This is a multi-part message in MIME format...

------------=_1641157590-74861-3434
Content-Type: text/plain

FOUS11 KWBC 022106
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
405 PM EST Sun Jan 02 2022

Valid 00Z Mon Jan 03 2022 - 00Z Thu Jan 06 2022

...Pacific Northwest to the Central Rockies...
Days 1-3...

Widespread snowfall across the Pacific Northwest through the
Central Rockies is likely the next three days as a closed low
southeast of Alaska slowly opens and pivots onshore WA Tuesday,
shedding sheared vorticity eastward into the Rockies by D3. This
will be accompanied by modest Pacific jet energy and mid-level
confluent flow to drive moisture into the region, with IVT
approaching 750 kg/m/s by D3. Snow levels through the period will
remain low, generally 1500-2500 ft D1 and D2, before climbing,
especially in OR and points east, D3 to 4000 ft as the more
significant moisture plume pivots onshore. With nearly continuous
moisture and forcing, snowfall is likely in the terrain each day
of the forecast period, and there exists a high risk for 12+
inches of snow both D1 and D2 in the WA/OR Cascades, the Olympics,
the northern CA ranges and into the Sawtooth of ID. 2-day snowfall
could exceed 5 feet in the Cascades, with several feet also likely
at the important Cascade mountain passes. Low probabilities for 4
inches extend into most of the Northwest valleys except the
Columbia Basin and lowlands around Seattle and Portland. By D3,
the best moisture begins to spill eastward as far as the High
Plains of WY, but forcing is a little less robust by this time.
This will produce moderate snowfall as far east as the Nebraska
Panhandle, and WPC probabilities for 4 inches are high in the
terrain from the WA Cascades through the Sawtooth, the NW WY
ranges, and into the Park Range of CO. Locally more than 12 inches
is possible in any of this higher terrain on Wednesday.


...Northern Plains and Great Lakes...
Days 2-3...

A shortwave dropping out of Alberta will interact with sheared
vorticity coming across the Pacific Northwest to produce a closed
low over the Upper Midwest on D3. This feature will be accompanied
by an increasingly coupled jet structure, and the overlap of this
ascent will produce a fast moving wave of low pressure moving
through the region on Wednesday. While this low will be fast
moving and in a region of modest moisture, a cold column
supporting above-climo SLRs will lead to moderate to heavy
snowfall accumulations D3. The primary band of synoptically forced
snowfall will move from ND Tuesday evening through Michigan by the
end of D3, and WPC probabilities are 10-30% for 4 inches in this
region. However, as the low ejects eastward through MI, robust LES
is likely to develop as flow pinches and CAA sets up over Lake
Superior from the north, and then curving off of Lake Michigan
into the L.P. This LES could be prolonged, and although inversion
heights are only progged to reach 6000-7000 ft, this will likely
overlap into the DGZ, and significant LES is likely, especially
across the U.P. and the Keweenaw Peninsula. WPC probabilities D3
are high for 6 inches here, with locally more than 1 foot possible.


...Southern Appalachians through Coastal New England...
Days 1-2...

...Increasing confidence in a significant winter storm impacting
the Mid-Atlantic...

Intensifying southern stream shortwave will continue to move
across the Southeast while amplifying into a closed low and then
lifting across the Mid-Atlantic Monday morning before ejecting to
off New England late Monday. This shortwave will be accompanied by
an impressive poleward arcing jet streak over southern ME, with
wind speeds progged to exceed the 90th percentile at 250mb over
Maine according to the SPC sounding climatology. The interaction
of these features with an impressive surface cold front and
associated baroclinic gradient will drive rapid surface low
pressure development. This low will move quickly across the region
spreading heavy precipitation northward, and a swath of heavy snow
has become much more likely tonight through Monday night.

The guidance this aftn have continued to trend stronger, a little
slower, and more NW with this system. The exception is the NAM,
but this model seems to be initializing a bit too far south
compared to reality and is not preferred. This trend suggests
another uptick in snowfall potential which is reflected in both
WSE mean/NBM 50th percentile, as well as the high end potential of
the 90th percentiles of these same ensemble clusters. While
antecedent conditions are quite warm, and many places may start as
rain before changing over, rapid CAA behind the cold front will
quickly transition rain to snow in many areas. This CAA will be
aided via impressive ascent within a pivoting deformation axis to
drive intense dynamic cooling of the column. Although SLRs will
vary greatly, starting very low and then increasing with time as
the column cools, notable overlap of -EPV* and ThetaE lapse rates
near or below 0 suggest CSI or even upright convection (thunder
snow) within the best deformation. This could produce snowfall
rates of 2+"/hr, which is reflected both by HREF snow
probabilities and the WPC snowband prototype tool, with the
highest chances across VA, MD, DE, into southern NJ. It is these
rates that will help overcome the low-level warmth and hostile
antecedent conditions to produce heavy snowfall.

Tonight, precipitation will occur as snow within the deformation
axis as far SW as northern AL and central TN where heavy snow
rates could produce a few inches of snowfall. However, the heavier precipitation will likely overspread the region from the mountains
of NC eastward through southern NJ where WAA and a blossoming
TROWAL will expand the precipitation shield, with a changeover
from rain to snow occurring from NW to SE, and all snow likely
well NW of the 850mb low center. This, again, will have an impact
on SLR, and the NBM SLR values were decreased closer to Cobb
numbers during transition, but then increased above NBM during the
period of heaviest snowfall to account for dynamics. While
confidence is lower than usual due to still tremendous model
spread in thermal structure, WPC probabilities have increased, and
now show a high chance for 4+ inches from the NC/TN mountains
northeast through central VA and across southern NJ on D1. Within
this axis, there are likely to be pockets of heavier snow, and WPC probabilities for more than 8 inches are above 60% in the NC/TN
mountains, with a secondary axis of greater than 50% just SE of
the I-95 corridor from central VA through southern NJ where
convective rates are most likely. It is possible a few locations
could receive double-digit snowfall before snow winds down from
west to east Monday evening.

Further NE, jet streak enhanced precipitation NW of the low could
produce moderate to heavy snow across far SE Long Island and
across the Cape and Islands into D2, where WPC probabilities for
more than 4 inches are as high as 40%.


Weiss


$$




------------=_1641157590-74861-3434
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. ------------=_1641157590-74861-3434--

--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

This is a multi-part message in MIME format...

------------=_1641160618-74861-3467
Content-Type: text/plain

FOUS11 KWBC 022156
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
456 PM EST Sun Jan 02 2022

Valid 00Z Mon Jan 03 2022 - 00Z Thu Jan 06 2022

...Pacific Northwest to the Central Rockies...
Days 1-3...

Widespread snowfall across the Pacific Northwest through the
Central Rockies is likely the next three days as a closed low
southeast of Alaska slowly opens and pivots onshore WA Tuesday,
shedding sheared vorticity eastward into the Rockies by D3. This
will be accompanied by modest Pacific jet energy and mid-level
confluent flow to drive moisture into the region, with IVT
approaching 750 kg/m/s by D3. Snow levels through the period will
remain low, generally 1500-2500 ft D1 and D2, before climbing,
especially in OR and points east, D3 to 4000 ft as the more
significant moisture plume pivots onshore. With nearly continuous
moisture and forcing, snowfall is likely in the terrain each day
of the forecast period, and there exists a high risk for 12+
inches of snow both D1 and D2 in the WA/OR Cascades, the Olympics,
the northern CA ranges and into the Sawtooth of ID. 2-day snowfall
could exceed 5 feet in the Cascades, with several feet also likely
at the important Cascade mountain passes. Low probabilities for 4
inches extend into most of the Northwest valleys except the
Columbia Basin and lowlands around Seattle and Portland. By D3,
the best moisture begins to spill eastward as far as the High
Plains of WY, but forcing is a little less robust by this time.
This will produce moderate snowfall as far east as the Nebraska
Panhandle, and WPC probabilities for 4 inches are high in the
terrain from the WA Cascades through the Sawtooth, the NW WY
ranges, and into the Park Range of CO. Locally more than 12 inches
is possible in any of this higher terrain on Wednesday.


...Northern Plains and Great Lakes...
Days 2-3...

A shortwave dropping out of Alberta will interact with sheared
vorticity coming across the Pacific Northwest to produce a closed
low over the Upper Midwest on D3. This feature will be accompanied
by an increasingly coupled jet structure, and the overlap of this
ascent will produce a fast moving wave of low pressure moving
through the region on Wednesday. While this low will be fast
moving and in a region of modest moisture, a cold column
supporting above-climo SLRs will lead to moderate to heavy
snowfall accumulations D3. The primary band of synoptically forced
snowfall will move from ND Tuesday evening through Michigan by the
end of D3, and WPC probabilities are 10-30% for 4 inches in this
region. However, as the low ejects eastward through MI, robust LES
is likely to develop as flow pinches and CAA sets up over Lake
Superior from the north, and then curving off of Lake Michigan
into the L.P. This LES could be prolonged, and although inversion
heights are only progged to reach 6000-7000 ft, this will likely
overlap into the DGZ, and significant LES is likely, especially
across the U.P. and the Keweenaw Peninsula. WPC probabilities D3
are high for 6 inches here, with locally more than 1 foot possible.


...Southern Appalachians through Coastal New England...
Days 1-2...

...Increasing confidence in a significant winter storm impacting
the Mid-Atlantic...

Intensifying southern stream shortwave will continue to move
across the Southeast while amplifying into a closed low and then
lifting across the Mid-Atlantic Monday morning before ejecting to
off New England late Monday. This shortwave will be accompanied by
an impressive poleward arcing jet streak over southern ME, with
wind speeds progged to exceed the 90th percentile at 250mb over
Maine according to the SPC sounding climatology. The interaction
of these features with an impressive surface cold front and
associated baroclinic gradient will drive rapid surface low
pressure development. This low will move quickly across the region
spreading heavy precipitation northward, and a swath of heavy snow
has become much more likely tonight through Monday night.

The guidance this aftn have continued to trend stronger, a little
slower, and more NW with this system. The exception is the NAM,
but this model seems to be initializing a bit too far south
compared to reality and is not preferred. This trend suggests
another uptick in snowfall potential which is reflected in both
WSE mean/NBM 50th percentile, as well as the high end potential of
the 90th percentiles of these same ensemble clusters. While
antecedent conditions are quite warm, and many places may start as
rain before changing over, rapid CAA behind the cold front will
quickly transition rain to snow in many areas. This CAA will be
aided via impressive ascent within a pivoting deformation axis to
drive intense dynamic cooling of the column. Although SLRs will
vary greatly, starting very low and then increasing with time as
the column cools, notable overlap of -EPV* and ThetaE lapse rates
near or below 0 suggest CSI or even upright convection (thunder
snow) within the best deformation. This could produce snowfall
rates of 2+"/hr, which is reflected both by HREF snow
probabilities and the WPC snowband prototype tool, with the
highest chances across VA, MD, DE, into southern NJ. It is these
rates that will help overcome the low-level warmth and hostile
antecedent conditions to produce heavy snowfall.

Tonight, precipitation will occur as snow within the deformation
axis as far SW as northern AL and central TN where heavy snow
rates could produce a few inches of snowfall. However, the heavier precipitation will likely overspread the region from the mountains
of NC eastward through southern NJ where WAA and a blossoming
TROWAL will expand the precipitation shield, with a changeover
from rain to snow occurring from NW to SE, and all snow likely
well NW of the 850mb low center. This, again, will have an impact
on SLR, and the NBM SLR values were decreased closer to Cobb
numbers during transition, but then increased above NBM during the
period of heaviest snowfall to account for dynamics. While
confidence is lower than usual due to still tremendous model
spread in thermal structure, WPC probabilities have increased, and
now show a high chance for 4+ inches from the NC/TN mountains
northeast through central VA and across southern NJ on D1. Within
this axis, there are likely to be pockets of heavier snow, and WPC probabilities for more than 8 inches are above 60% in the NC/TN
mountains, with a secondary axis of greater than 50% just SE of
the I-95 corridor from central VA through southern NJ where
convective rates are most likely. It is possible a few locations
could receive double-digit snowfall before snow winds down from
west to east Monday evening.

Further NE, jet streak enhanced precipitation NW of the low could
produce moderate to heavy snow across far SE Long Island and
across the Cape and Islands into D2, where WPC probabilities for
more than 4 inches are as high as 40%.


Weiss


~~~ Key Messages for the Southern Appalachians through Coastal New
England Winter Storm ~~~

Rain will likely change over to moderate snow across northern
Alabama, central Tennessee, and northern Georgia tonight. A few
inches of snowfall will likely produce hazardous travel.

Heavy wet snow is likely beginning early Monday from the Southern
Appalachians through much of the Mid-Atlantic. Snowfall is
expected to exceed 4" in many locations, with local amounts
approaching 10" possible.

Snowfall rates may reach 2"/hr at times, and thunder-snow is
possible. These rates combined with gusty winds will produce
dangerous travel conditions. Heavy wet snow accumulating on power
lines and tree limbs could create scattered power outages.

Very cold temperatures Monday night may allow roads to re-freeze,
producing additional dangerous travel even after the snow has
ended.


$$




------------=_1641160618-74861-3467
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. ------------=_1641160618-74861-3467--

--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

This is a multi-part message in MIME format...

------------=_1641197421-74861-3755
Content-Type: text/plain

FOUS11 KWBC 030810
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
309 AM EST Mon Jan 03 2022

Valid 12Z Mon Jan 03 2022 - 12Z Thu Jan 06 2022

...Pacific Northwest to the Central Rockies...
Days 1-3...

Widespread snowfall across the Pacific Northwest through the
Central Rockies is likely the next three days as a closed low
southeast of Alaska slowly opens and pivots onshore WA Tuesday,
shedding sheared vorticity eastward into the Rockies later on
Tuesday. This will be accompanied by modest Pacific jet energy and
mid-level confluent flow to drive moisture into the region, with
IVT approaching 750 kg/m/s. Snow levels through the period will
remain low, generally 1500-2500 ft initially, before climbing,
especially in OR and points east, D3 to 4000 ft as the more
significant moisture plume pivots onshore. A prolonged fetch of
moisture coincident with the favorable lift will drive impressive
snow totals for the Olympics, OR/WA Cascades, the northern CA
ranges as well as eastward into the Sawtooth of ID. Several feet
of accumulations are likely for the important Cascade mountain
passes with some isolated 4-5 feet totals possible for the OR
Cascades. Late on D2 into D3, the better moisture spills eastward
across the northern to central Rockies. Tightening baroclinic zone
and upslope component will support snowfall across the High Plains
of WY into portions of the Plains. High probabilities for 4 inches
extend across southeast WY into western/central NE with even a
moderate signal for at least 6 inches.


...Northern Plains and Great Lakes...
Days 2-3...

Shortwave trough coming from Alberta and sheared vorticity from
the Pacific Northwest will work together to close off a 500 mb low
over the western Great Lakes by Wednesday. Surface cyclogenesis
over the Plains will deepen as it tracks through the Upper
Mississippi River Valley. This favorable forcing for ascent,
modest moisture in place within the very cold thermal profile will
support a period of fluffy snow late Tuesday through Wednesday
followed by increasing lake effect snows as the system departs.
Plummeting 850 mb temperatures and a prolonged fetch of favorable
wind flow off Lake Superior and Lake Michigan should lead to some
hefty totals through the 3 day period. The latest WPC
probabilities show slight to moderate probabilities for 4 inches
across the northern Plains with the main low pressure system then
high probabilities off Lake Superior. In fact, probabilities for 8
inches are high and a significant LES event is likely, especially
across the U.P. and the Keweenaw Peninsula.


...Southern Appalachians through Coastal New England...
Day 1...

...Significant Winter Storm Today for the Mid-Atlantic...

Low pressure deepening this morning over the Southeast is forecast
to track northeast off the Mid-Atlantic coast later today while
aloft, an anomalously deep, compact closed low pivots through the
Southern Appalachians. This is also accompanied by an impressive
poleward arcing jet streak over southern Maine. Altogether, this
forcing for ascent will continue to drive widespread banded
precipitation today. A surface front has dropped southward through
the Mid-Atlantic and this will set the stage for a changeover from
rain to wet snow this morning. A narrow zone of intense
frontogenetical forcing will drive intense snow rates this
morning, most likely from central VA northeast toward the DC metro
and southern MD, DE, and southern NJ where the HREF probabilities
show near certain 1"/hr snow rates with even moderate to high
probabilities of 2"/hr rates at times. It is these rates that will
help overcome the low-level warmth and hostile antecedent
conditions to produce heavy snowfall. Overall for this forecast
iteration, there wasn't much change to the footprint of the
heaviest snow axis as the 00Z guidance has locked in on the
general track and strength of the system. This gives a bit more
confidence in some of the higher QPF values seen and as a result,
a focused area of higher totals was incorporated for portions of
central VA and southern DelMarVa. The signal for localized 8-12"
totals has increased there. The latest WPC probabilities are high
for at least 6 inches for the 24-hour period ending 12Z Tuesday
with now a moderate signal for 8 inches from southern DC metro
toward central NJ. The system will brush portions of eastern Long
Island and across the Cape and Islands as well with a few inches
of snow. WPC probabilities for 4 inches have increased to near 70
percent during the day 1 period.

Taylor


~~~ Key Messages for the Southern Appalachians through
Mid-Atlantic Winter Storm ~~~

-Winter storm will lead to significant travel disruptions and
dangerous driving conditions today across the Southern
Appalachians through the Mid-Atlantic.

-6-8" totals are expected across the Southern Appalachians and
portions of the Mid-Atlantic. Localized higher amounts up to 8-12"
likely.

-Very intense snowfall rates near 2"/hr will occur this morning
and thunder-snow is likely. Rapidly deteriorating road conditions
and severely reduced visibility should be expected.

-The heavy wet snow will accumulate on trees and power lines and
this could lead to power outages.

-Very cold temperatures tonight may allow untreated roads to
re-freeze, producing additional dangerous travel even after the
snow has ended.


$$




------------=_1641197421-74861-3755
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. ------------=_1641197421-74861-3755--

--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

This is a multi-part message in MIME format...

------------=_1641242396-74861-4908
Content-Type: text/plain

FOUS11 KWBC 032039
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
339 PM EST Mon Jan 03 2022

Valid 00Z Tue Jan 04 2022 - 00Z Fri Jan 07 2022

...Pacific Northwest to the Central Rockies...
Days 1-3...
Widespread snowfall across the Pacific Northwest into the northern
and central Rockies is likely through midweek as a closed low
southeast of Alaska opens, with sheared energy spreading across
the region. This will be accompanied by modest Pacific jet energy
and mid-level confluent flow to drive moisture into the region,
with PWs increasing to 1.5 to 2 standard deviations above normal
across Oregon and Northern California by late tomorrow, followed
by moisture deepening farther north and east as the period
progresses. Snow levels are expected to remain low across the
Pacific Northwest through Tuesday, before building across Oregon
as an upper ridge axis begins to move onshore -- driving a frontal
boundary northeast by late Wednesday. The front will continue to
push farther north, with additional snow level increases across
Oregon into Washington ahead of an approaching shortwave. This
shortwave will accompanied by another shot of deeper moisture --
raising the threat for heavy precipitation. As the cold air aloft
retreats, lingering cold air at the surface may set the stage for
mixed precipitation, including accumulating ice across the valleys
of Washington and northern Oregon.

Heaviest snow accumulations through late Tuesday are expected to
center along the Oregon Cascades, where WPC probabilities indicate
that accumulations of 1-2 feet are likely. Locally heavy
accumulations are likely farther north in the Olympics and
northern Cascades, as well as south into the Klamath Mountains and
northern Sierra. The eastern Oregon mountains as well as portions
of the northern Rockies, including the Sawtooth, are expected to
see locally heavy accumulations as well.

Unsettled weather, including locally heavy snow is expected to
continue across the Cascades into the northern Rockies on
Wednesday. As energy and moisture continue to spread southeast,
the threat for heavy snow is expected to increase across the
western Wyoming, northern Utah, and north-central Colorado ranges
-- with WPC probabilities indicating significant potential for
accumulations of a foot or more by late Wednesday.

Beginning late Wednesday and continuing into Thursday, an
approaching shortwave will focus the threat for heavy snow farther
north, with heavy snows likely for the Washington Cascades.
Locally heavy snows are also likely for the Blue Mountains and
portions of the northern Rockies, especially the northern to
central Idaho ranges.

...Northern Plains and Great Lakes...
Days 2-3...
Shortwave trough coming from Alberta and sheared vorticity from
the Pacific Northwest will work together to close off a 500 mb low
over the western Great Lakes by Wednesday. Surface cyclogenesis
over the Plains will deepen as it tracks through the Upper
Mississippi River Valley. This favorable forcing for ascent,
modest moisture in place within the very cold thermal profile will
support a period of fluffy snow late Tuesday through Wednesday
followed by increasing lake effect snows as the system departs.
Plummeting 850 mb temperatures and a prolonged fetch of favorable
wind flow off Lake Superior and Lake Michigan should lead to some
hefty totals through the period. The latest WPC probabilities show
high probabilities for 6 inches of snow or more by late Wednesday
across the western U.P. of Michigan, including the Keweenaw
Peninsula.

The upper low is forecast to quickly open and lift northeast along
the St. Lawrence Valley Wednesday night into Thursday. As
northerly to northwesterly winds continue to support lake effect
activity off of lakes Superior and Michigan, westerly flow and low
level cold air will support the development of lake effect snows
east of lakes Erie and Ontario into western New York and the Tug
Hill region.

...Central High Plains to the Ohio Valley...
Days 2-3...
Increasing divergence along the left-exit region of an upper jet
extending southeast from the northern Rockies, overlapping strong
low-to-mid level frontogenesis, is expected to support the
increasing potential for heavy snow development from southeastern
Wyoming into the Nebraska Panhandle on Wednesday. WPC
probabilities indicate at least a moderate threat for snow
accumulations of 4-inches or more across this region. The threat
for heavy snow is less certain farther east, but a stripe of at
least light accumulations is expected across Kansas and Nebraska
into Missouri late Wednesday into Thursday. By late Thursday, the probabilities for heavier amounts begins to increase from southern
Missouri into the Ohio Valley as amplifying flow over the Plains
into the Mississippi valley begins to tap some deeper moisture
from the Gulf.

Pereira/Taylor


~~~ Key Messages for the Southeast through Mid-Atlantic Winter
Storm ~~~

-Winter storm will lead to significant travel disruptions and
dangerous driving conditions today across the Southern
Appalachians through the Mid-Atlantic.

-6-8" totals are expected across the Southern Appalachians and
portions of the Mid-Atlantic. Localized higher amounts up to 8-12"
likely.

-Very intense snowfall rates near 2"/hr will occur this morning
and thunder-snow is likely. Rapidly deteriorating road conditions
and severely reduced visibility should be expected.

-The heavy wet snow will accumulate on trees and power lines and
this could lead to power outages.

-Very cold temperatures tonight may allow untreated roads to
re-freeze, producing additional dangerous travel even after the
snow has ended.


$$




------------=_1641242396-74861-4908
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. ------------=_1641242396-74861-4908--

--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

This is a multi-part message in MIME format...

------------=_1641283836-74861-5259
Content-Type: text/plain

FOUS11 KWBC 040810
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
309 AM EST Tue Jan 04 2022

Valid 12Z Tue Jan 04 2022 - 12Z Fri Jan 07 2022

...Pacific Northwest to the Central Rockies...
Days 1-3...

Unsettled, active weather will continue through the forecast
period across the Pacific Northwest. A closed low well southeast
of Alaska will open up with pieces of sheared energy spreading
into the region through the day 1 period. Modest Pacific jet
energy and confluent flow in the mid-levels will drive an
impressive moisture plume into the region where PWs up to +2 sigma
are expected across OR/WA. Northward morning frontal boundary will
help lift snow levels that are initially low this morning as the
upper ridge builds/pushes north. Another shortwave trough then
approaches northwest Washington late tonight into Wednesday. As
the cold air aloft retreats, lingering cold air at the surface may
set the stage for mixed precipitation, including accumulating ice
across the valleys of Washington and northern Oregon.

Beginning late Wednesday and continuing into Thursday, an
approaching shortwave will focus the threat for heavy snow farther
north, with heavy snows likely for the Washington Cascades.
Locally heavy snows are also likely for the Blue Mountains and
portions of the northern Rockies, especially the northern to
central Idaho ranges.

...Northern Plains and Great Lakes...
Days 1-3...
Shortwave trough energy originating from Alberta and a piece of
sheared vorticity from the Pacific Northwest works together to
eventually carve out a closed 500 mb low over the western Great
Lakes Wednesday. A strengthening area of low pressure is then
forecast to track from eastern Montana toward MSP then the
northern Great Lakes. A corridor of frontogenetical forcing within
the very cold air will support moderate to locally heavy snowfall
across the northern Plains to Upper Midwest late tonight into
early Wednesday and then as the system passes east of the Lakes,
the very favorable wind direction and cold air will bring a
prolonged, potentially significant, lake effect snow event to the
Great Lakes. SLRs approaching 20:1 will help drive higher snow
totals in excess of a foot locally for the favored areas of Lake
Superior, Michigan, and perhaps Erie/Ontario snow belt areas. The
latest WPC probabilities for 6 inches are moderate to locally high
for Superior/Michigan snow belt areas.


...Central High Plains...
Day 2...
Increasing divergence along the left-exit region of an upper jet
extending southeast from the northern Rockies, overlapping strong
low-to-mid level frontogenesis, is expected to support the
increasing potential for heavy snow development from southeastern
Wyoming into the Nebraska Panhandle on Wednesday. WPC
probabilities indicate at least a moderate threat for snow
accumulations of 4-inches or more across this region. The threat
for heavy snow is less certain farther east, but a stripe of at
least light accumulations is expected across Kansas and Nebraska
into Missouri late Wednesday into Thursday.


...Ohio Valley into Mid-Atlantic/Northeast...
Day 3...
Shortwave energy crossing the central U.S. in the quasi-zonal flow
begins to sharpen and dig as it approaches the lower Ohio Valley
Thursday. An area of low pressure over the Deep South is then
expected to strengthen as it lifts northeast through the southern
Appalachians then off the Mid-Atlantic coast. Modest moisture
being tapped from the Gulf will help drive widespread
precipitation across the lower Ohio Valley through much of the
central/southern Appalachians into the Mid-Atlantic and Northeast.
With the current forecast track, a transition zone of rain/snow
would potentially bisect the urban corridor with the current
favored area for accumulating snow to the west/interior areas but
there remains some considerable uncertainty in the eventual low
pressure track and therefore the amount/depth of cold air in
place. But there is an increasing signal for several inches of
snow for portions of eastern Kentucky into West Virginia through
the end of Day 3 and the latest probabilistic guidance has
increased subsequently. The latest WPC probabilities for 4 inches
are now high across eastern Kentucky through much of West Virginia
with a broad area of moderate probabilities around it from central
Kentucky into the Mid-Atlantic.


Taylor/Pereira



$$




------------=_1641283836-74861-5259
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. ------------=_1641283836-74861-5259--

--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

This is a multi-part message in MIME format...

------------=_1641330915-74861-5555
Content-Type: text/plain

FOUS11 KWBC 042115
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
414 PM EST Tue Jan 04 2022

Valid 00Z Wed Jan 05 2022 - 00Z Sat Jan 08 2022

...Pacific Northwest to the Central Rockies...
Days 1-3...

Strong upper high northwest of Alaska will favor troughing to its
south out of the Gulf of Alaska into western British Columbia and
the Pacific Northwest as a series of jet streaks pass through. By
the end of the week, troughing from the Gulf of Alaska as well as
the northern Pacific in the mid-latitudes will increase broader
troughing into much of the Northwest with two attendant surface
systems moving into the region. Working in tandem, these systems
will promote a surge in moisture into western Washington by late
Wed/early Thu with precipitable water values over 1 inch on the
coast which is +2 to +3 sigma. This will shift inland across Idaho
on Thursday and into Wyoming/Utah as well where snowfall will be
significant in higher elevations. Temperatures will moderate as
milder air draws northeastward, but initially cold surface
temperatures in lowland/valley locations east of the Cascades will
support some freezing rain (also perhaps west of the Cascades
before the column warms completely). Heavy snow is forecast for
the Cascades with significant accumulating snow across the passes
Thursday. Snow levels will rise late Thu into Fri over western WA
and OR over 5000ft before trending down as the upper trough moves
in. WPC probabilities of at least 12 inches of snow are moderate
to high each day over the Washington Cascades and mountainous
Idaho/western Montana.

...Northern Plains and Great Lakes...
Days 1-2...
Shortwave trough energy originating from Alberta and a piece of
sheared vorticity from the Pacific Northwest works together to
eventually carve out a closed 500 mb low over the western Great
Lakes Wednesday. At the surface, low pressure amplifying over the
northern Plains is forecast to track northeast across southern
Minnesota into Wisconsin overnight. A corridor of frontogenetical
forcing within the very cold air will support moderate to locally
heavy snowfall across the northern Plains to Upper Midwest late
tonight into early Wednesday and then as the system passes east of
the Lakes, the very favorable wind direction and cold air will
bring a prolonged, potentially significant, lake effect snow event
to the Great Lakes. SLRs approaching 20:1 will help drive higher
snow totals in excess of a foot locally for the favored areas of
Lake Superior, Michigan, and perhaps Erie/Ontario snow belt areas.
The latest WPC probabilities for 6 inches are moderate to locally
high for the Superior/Michigan/Erie/Ontario snow belt areas.


...Central High Plains...
Day 2...
Increasing divergence along the left-exit region of an upper jet
extending southeast from the northern Rockies, overlapping strong
low-to-mid level frontogenesis, is expected to support the
increasing potential for heavy snow development from southeastern
Wyoming into the Nebraska Panhandle on Wednesday. WPC
probabilities continue to increase, indicating a high threat for
accumulations of 4-inches or more centered across this region.
The threat for heavy snow is less certain farther east, but a
stripe of at least light accumulations is expected across Kansas
and Nebraska into Missouri late Wednesday into Thursday.


...Tennessee and Ohio Valleys into Mid-Atlantic/Northeast...
Day 2-3...
Shortwave energy crossing the central U.S. in the quasi-zonal flow
begins to sharpen and dig as it approaches the Tennessee and lower
Ohio valleys Thursday. An area of low pressure over the Deep South
is then expected to strengthen as it lifts northeast through the
southern Appalachians then off the Mid-Atlantic coast Friday
morning. Then on Friday, as the associated shortwave begins to
assume a negative tilt and lift northeast, the surface low is
expected to rapidly intensify and track along the Northeast coast.
Modest moisture being tapped from the Gulf will help drive
widespread precipitation across the lower Ohio Valley through much
of the central/southern Appalachians into the Mid-Atlantic and
Northeast. As noted in previous discussions, there remains
considerable uncertainty in the eventual low pressure track and
therefore the amount/depth of cold air in place and its potential
impacts. However, there remains a significant signal for several
inches of snow for portions of eastern Kentucky into West Virginia
through by early Friday. The latest WPC probabilities for 4 inches
remain high across eastern Kentucky through much of West Virginia
with a broad area of moderate probabilities around it from central
Kentucky into the Mid-Atlantic. As the system intensifies, the
potential for significant snows is expected to increase from the
northern Mid-Atlantic to New England, including the I-95 corridor.
Latest WPC probabilities show moderate probabilities for snowfall accumulations of 4 inches or more from the Baltimore metro through
eastern Maine.

Fracasso/Pereira/Taylor

~~~ Key Messages for the Tennessee and Ohio Valleys to the
Northeast Winter Storm ~~~

-There is potential for another storm to impact portions of the
Tennessee and lower Ohio valleys, central Appalachians,
Mid-Atlantic, and Northeast Thursday through Friday.

-Potential exists for several inches of snow and widespread
hazardous travel conditions.

-Mixed precipitation, including freezing rain, is possible south
of the heavier snow in the Tennessee Valley.

-There remains a lot of uncertainty in the track of the storm and
potential snow/ice amounts, but an impactful event is becoming
increasingly likely.




$$




------------=_1641330915-74861-5555
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. ------------=_1641330915-74861-5555--

--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

This is a multi-part message in MIME format...

------------=_1641371781-74861-5726
Content-Type: text/plain

FOUS11 KWBC 050836
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
335 AM EST Wed Jan 05 2022

Valid 12Z Wed Jan 05 2022 - 12Z Sat Jan 08 2022

...Pacific Northwest to the Central Rockies...
Days 1-3...

Strong upper high northwest of Alaska will favor troughing to its
south out of the Gulf of Alaska into western British Columbia and
the Pacific Northwest as a series of jet streaks pass through. By
the end of the week, troughing from the Gulf of Alaska as well as
the northern Pacific in the mid-latitudes will increase broader
troughing into much of the Northwest with two attendant surface
systems moving into the region. Working in tandem, these systems
will promote a surge in moisture into western Washington by late
Wed/early Thu with precipitable water values over 1 inch on the
coast which is +2 to +3 sigma. This will shift inland across Idaho
on Thursday and into Wyoming/Utah as well where snowfall will be
significant in higher elevations. Temperatures will moderate as
milder air draws northeastward, but initially cold surface
temperatures in lowland/valley locations east of the Cascades will
support some freezing rain (also perhaps west of the Cascades
before the column warms completely). Heavy snow is forecast for
the Cascades with significant accumulating snow across the passes
Thursday. Snow levels will rise late Thu into Fri over western WA
and OR over 5000ft before trending down as the upper trough moves
in. WPC probabilities of at least 12 inches of snow are moderate
to high each day over the Washington Cascades and mountainous
Idaho/western Montana.

...Northern Plains and Great Lakes...
Days 1-2...

Closed low forming over the Great Lakes and low pressure centered
over Wisconsin will track east/northeast through today/tonight.
Strong frontogenetical forcing and wrap around moisture on the
backside of the deepening low will produce several inches of
light, fluffy snow early this morning. Combined with very strong
winds, blizzard conditions are expected to persist through
portions of the day 1 period. As the low lifts north/northeast of
the Great Lakes, northerly to northwesterly winds will increase
setting up a favorable long duration potentially significant lake
effect regime. The much colder air and maximum lift well within
the DGZ supports SLRs 20:1 or even a bit higher in the more
intense snow bands. As a result, total accumulations in excess of
8 inches are expected off the Lakes, particularly for the favored
snow belt areas where isolated totals between 12-18 inches will be
possible.


...Central High Plains...
Day 2...
Sheared vorticity moving through the developing longwave trough
within a zone of increasing upper level diffluence and overlapping
low to mid level frontogenesis will bring a period of locally
heavy snowfall to portions of southeastern Wyoming into the
Nebraska Panhandle today/tonight. The latest WPC probabilities are
high for at least 4 inches across southeast WY with even a narrow
high probability for 8 inches. Probabilities for heavy snow drop
off considerably moving into central Nebraska, Kansas and Missouri
where light accumulations are expected.


...Tennessee and Ohio Valleys into Mid-Atlantic/Northeast...
Day 2-3...

Shortwave energy crossing the central U.S. in the quasi-zonal flow
begins to sharpen and dig as it approaches the TN/OH Valley
Thursday as an area of low pressure develops off the southeastward
moving frontal boundary. This low is expected to track through the
southern Appalachians before exiting off the Mid-Atlantic coast
early Friday morning. Then on Friday, as the associated shortwave
begins to assume a negative tilt and lift northeast, the surface
low is expected to rapidly intensify and track northeast,
potentially affecting the Northeast/New England region. This
forecast cycle showed an eastern trend, keeping the low track far
enough offshore such that the QPF/snow forecast trended downward,
especially inland/interior areas. With the signal for the system
to be 1) more offshore and 2) very fast moving - probabilities of
heavy snow have decreased this cycle, however there continues to
be some ensemble support for a stronger/closer system so over the
next several days the details will ironed out. The latest WPC
probabilities show the greatest chances for at least 4 inches
across eastern KY through WY, especially for the favored
terrain/upslope areas while those probabilities drop off to the
slight/moderate range for the Mid-Atlantic. Given the continued
uncertainty for southern New England and coastal Maine, the
highest probabilities remain right along the coast.

Taylor/Fracasso/Pereira

~~~ Key Messages for the Tennessee and Ohio Valleys to the
Northeast Winter Storm ~~~

-A winter storm is increasingly likely to impact portions of the
Ohio and Tennessee Valleys into the southern/central Appalachians
Thursday into Thursday night.

-Several inches of snow and a zone of mixed precipitation
including freezing rain is likely to cause travel disruptions and
hazardous travel conditions.

-As the system moves through the Mid-Atlantic and Northeast,
accumulating snow is likely Thursday night into Friday where a few
inches of snow will be possible. However, there remains a lot of
uncertainty in the track and potential amounts, especially for the
Northeast and New England.





$$




------------=_1641371781-74861-5726
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. ------------=_1641371781-74861-5726--

--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

This is a multi-part message in MIME format...

------------=_1641417597-74861-6115
Content-Type: text/plain

FOUS11 KWBC 052119
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
419 PM EST Wed Jan 05 2022

Valid 00Z Thu Jan 06 2022 - 00Z Sun Jan 09 2022

...Pacific Northwest to the Central Rockies...
Days 1-3...

Strong upper high northwest of Alaska will favor troughing to its
south out of the Gulf of Alaska into western British Columbia and
the Pacific Northwest as a series of jet streaks pass through. By
the end of the week, troughing from the Gulf of Alaska as well as
the northern Pacific in the mid-latitudes will increase broader
troughing into much of the Northwest with two attendant surface
systems moving into the region. Working in tandem, these systems
will promote a surge in moisture into western Washington by late
today/early Thu with precipitable water values over 1 inch on the
coast which is +2 to +3 sigma. This will shift inland across Idaho
on Thursday and into Wyoming/Utah as well where snowfall will be
significant in higher elevations. Temperatures will moderate as
milder air draws northeastward, but initially cold surface
temperatures in lowland/valley locations east of the Cascades will
support some freezing rain (also perhaps west of the Cascades
before the column warms completely). Heavy snow is forecast for
the Cascades with significant accumulating snow across the passes
Thursday. Snow levels will rise late Thu into Fri over western WA
and OR over 5000ft before trending down as the upper trough moves
in. For Days 1 and 2, WPC probabilities of at least 12 inches of
snow are moderate to high across the Washington Cascades and
mountainous Idaho/western Montana. By late Friday and continuing
through Saturday, the potential for heavy snow is expected to
diminish as the upper trough shifts east and an upper ridge begins
to move onshore.

...Northern Plains and Great Lakes...
Days 1-2...

As an upper low transitions to an open wave and lifts
north/northeast of the Great Lakes, northerly to northwesterly
winds will increase setting up a favorable long duration
potentially significant lake effect regime. The much colder air
and maximum lift well within the DGZ supports SLRs 20:1 or even a
bit higher in the more intense snow bands. As a result, total
accumulations in excess of 8 inches are expected off the Lakes,
particularly for the favored snow belt areas where isolated totals
of a foot or more are possible. Snows are expected to diminish on
Friday as a shortwave ridge moves east across the region.


...Tennessee and Ohio Valleys into Mid-Atlantic/Northeast...
Days 1-2...

Shortwave energy crossing the central U.S. in the quasi-zonal flow
begins to sharpen and dig as it approaches the TN/OH Valley
Thursday as an area of low pressure develops off the southeastward
moving frontal boundary. This low is expected to track through the
southern Appalachians before exiting off the Mid-Atlantic coast
early Friday morning. Then on Friday, as the associated shortwave
begins to assume a negative tilt and lift northeast, the surface
low is expected to rapidly intensify and track northeast,
potentially affecting the Northeast/New England region. While
uncertainty remains, the consensus of the 12Z deterministic model
cycle continued to show a progressive system with an offshore
track that would limit the potential for heavy snow well inland
across the Northeast. However, there continues to be some
ensemble support for a stronger/closer system so over the next
several days the details will ironed out.

For the Mid-South to the central Appalachians, the latest WPC
probabilities show the greatest chances for at least 4 inches from
central Kentucky and Middle Tennessee through West Virginia,
especially for the favored terrain/upslope areas, while those
probabilities drop off to the slight/moderate range for the
Mid-Atlantic. In addition to the orographic ascent, models are
indicating a period of strong forcing supported by low-to-mid
level frontogenesis overlapped by a coupled upper jet that may
support banded heavy snow (1+ inch/hr rates) developing and
translating east across Kentucky and Tennessee into the
Appalachians on Thursday. South of the heavier snow, models
continue to present a significant signal for mixed precipitation
and the potential for accumulating freezing rain across portions
of the Tennessee Valley. Across the Northeast, given the
continued uncertainty, for southern New England and coastal Maine,
the highest probabilities remain centered near the coast.

Pereira/Taylor

~~~ Key Messages for the Tennessee and Ohio Valleys to the
Northeast Winter Storm ~~~

- A winter storm is likely to impact areas from the Mid-South to
the Northeast Thursday and Friday.

- Several inches of heavy snow and a zone of mixed precipitation,
including freezing rain, is likely to cause travel disruptions and
hazardous to potentially dangerous road conditions from the
Mid-South to the southern and central Appalachians Thursday and
Thursday night.

- Accumulating snow, heavy in places, is likely as the system
moves through the Mid-Atlantic and Northeast Thursday night into
Friday.

- There remains uncertainty in the track and potential snow
amounts, particularly for the Northeast and New England.






$$




------------=_1641417597-74861-6115
Content-Type: text/plain; charset="US-ASCII"
Content-Disposition: inline
Content-Transfer-Encoding: 7BIT

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. ------------=_1641417597-74861-6115--

--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)