Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 PM EST Wed Jan 14 2026

Valid 12Z Sat Jan 17 2026 - 12Z Wed Jan 21 2026

...The high wind event late this week in the Northern & Central
Plains and nearby Colorado and Wyoming Rockies could last into
Sunday...

20Z Update: The 12Z model guidance suite is in excellent synoptic
scale agreement with the amplified upper level flow pattern that
will be in place, particularly through Monday before some
differences start becoming more evident. The main thing to watch
going into the upcoming weekend will be the evolution of a
potential coastal low pressure system that could bring impactful
winter weather to parts of the East Coast. There has been a more
westward trend in the latest guidance with the low off the coast of
the Carolinas on Sunday and the inland extent of the precipitation
shield, with the GFS indicating a more pronounced trend towards a
winter storm from the eastern Carolinas to southern New England,
whereas the non-NCEP guidance features a solution with
precipitation confined closer to the coast. Interests across the
East Coast should continue to closely monitor future forecasts
since changes are likely going forward. In addition to the coastal
low, lake effect snow will continue to make weather headlines for
most of this forecast period, and QPF was raised and blended with
GFS/ECMWF/CMC guidance to better depict mesoscale banding features
that is not well accounted for in the NBM. The previous forecast
discussion is appended below for reference. /Hamrick
-----------------------

...Guidance/Predictability Assessment...
The 00z model guidance remains generally agreeable on the broader
pattern through the medium range period, with a slow
broadening/breakdown of the ridge/trough couplet across the Lower
48. The greatest differences are related to embedded short- wave
timing within the upper-trough and associated system development at
the surface. The largest difference in the guidance compared to
this time yesterday is a stronger shortwave rounding the base of
the Eastern Trough, which leads to cyclogenesis at some distance
offshore the Southeast/Carolinas on Sunday. The 00z GFS/00z UKMET
are the sharpest, which don't befit the breadth of the upper level
trough.

The blend for the pressures, fronts, and 500 hPa heights is one
composed of even amounts of the deterministic guidance early
before inclusion of the 12z ECMWF/00z NAEFS means was used for the
detail issues later on. The 01z NBM QPF appeared too limited due to
its low bias with the light/moderate precipitation expected, so
included some of the 13/12z ECMWF and 13/18z GFS QPF to help deal
with the issue, both broadly around the Great Lakes and eventually
for the Pacific Northwest next Wednesday. It's possible later NBM
cycles and future WPC forecasts get wetter across portions of the
Mid- Atlantic and New England states around the Sunday time frame.


...Weather/Hazards Highlights...
This remains a relatively dry pattern with generally offshore flow
from the continent and downslope winds from the Rockies, so no
excessive rainfall outlook areas were necessary for Saturday and
Sunday. Lake effect/enhanced snowfall will remain a fixture near
and downwind of the Great Lakes as a series of shortwaves
aloft/clipper systems move within and through the broad troughing
over the Plains, Great Lakes, and East. Snow will also be possible
for the Northern Plains, Midwest, and Appalachians/Northeast.
Portions of the Southwest and Gulf coast late should see sufficient
moisture intrusion for rain, at times.

The new fly in the ointment is a new-to-the-forecast cyclone that
forms at some distance offshore the Carolinas/Southeast, which then
moves northeast from Sunday onward. The 00z GFS/00z UKMET are much
closer to the coast with the surface low/sharper aloft than the
00z Canadian/00z ECMWF. Used a compromise of the available
guidance here as a starting point, which will likely need
adjustments in future cycles, along with QPF near the East Coast.
There is some chance for accumulating snow from the Southern
Appalachians through the southern/central Mid- Atlantic States into
southern New England from late Saturday into early Monday; bears
watching to see if the guidance can converge further with this
feature and possible snow and near and offshore wind impacts.

Below average temperatures are expected for the eastern portion of
the Lower 48, while much of the West and High Plains will have
above average temperatures. There is significant potential for high
winds for portions of the Northern/Central Plains, portions of the
Front Range of CO, and some of the mountains bordering central WY
from Friday into Sunday, with gusts up to 70 mph possible Saturday
and Sunday. Additionally, is also some indication for enhanced
offshore wind potential for central and northern California Sunday
onward due to enhanced high pressure across the Great Basin.


Roth/Putnam


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
258 PM EST Thu Jan 15 2026

Valid 12Z Sun Jan 18 2026 - 12Z Thu Jan 22 2026

***Heavy lake effect snows are likely for the first half of next
week from Michigan to Upstate New York***

20Z Update: The 12Z model guidance suite remains in very good
agreement overall for Sunday into early next week, with a
deterministic model blend used as a starting point for fronts and
pressures. In terms of QPF, the NBM had a reasonable depiction of
QPF for most areas, but probably too light with lake effect snow
bands, so QPF was raised a little from Michigan to Upstate New York
to better account for this, with areas downwind of Lake Ontario
potentially getting 1-2+ feet of accumulation. For the coastal low
on Sunday, the models have for the most part stabilized with the
QPF mainly confined to the coastal plain of the Carolinas and
southeast Virginia, and the GFS has trended closer to the ECMWF
over the past few model cycles. The shortwave that approaches from
the west does not acquire negative tilt until after it exits the
East Coast, and this limits the potential for a more impactful
winter storm. Towards the end of the forecast period Thursday, the
overall flow pattern becomes a little more zonal compared to
earlier in the week, and model differences become more apparent, so
the ensemble means were increased to about 40% by that time. The
previous forecast discussion is appended below for reference.
/Hamrick
-----------------


...Guidance/Predictability Assessment...

The very amplified pattern of a ridge up the West Coast into
Southeast Alaska with a deep low over Hudson Bay and associated
troughing east of the Rockies persists into next week. Through the
middle of next week indications are that the ridge will shift off
the West Coast (and into mainland Alaska) as the sprawling low
further expands. The series of shortwave troughs rounding the
Hudson Bay low will remain key for forecast agreement. The WPC Days
3-7 surface pressures and fronts forecast was based on a blend
that most resembled the 18Z EC-AIFS which by Day 4 was mainly the
EC and the ECENS mean.

Low QPF bias in the 01Z NBM v4.3 QPF was mitigated using the 18Z
EC-
AIFS, 12Z ECMWF, and the NBM v5.0 with some 18Z GFS to enhance lake
effect precip and 12Z CMC for lower TX Gulf coast rainfall starting
on Tuesday.


...Weather/Hazards Highlights...

Heavy rainfall remains limited over the CONUS until western Gulf
low pressure/frontal pattern allows southern/coastal Texas to see
some heavier rain starting on Tuesday. The Days 4/5 EROs remain
nil.

A baroclinic leaf developing over the southeast early Sunday
intensifies through the day with low pressure developing off the
Eastern Seaboard. Backside precip looks to be snow over interior
locations of the Southeast and along the Mid-Atlantic/Northeast
coasts. Meanwhile a potent northern stream reinforcing trough
swings across the northern Plains and Great Lakes Sunday through
Monday. Powerful winds will accompany this over the northern Plains
with lake effect/enhanced snowfall. The next wave over the northern
Plains/Great Lakes looks to be Tuesday afternoon through Wednesday
night with additional LES. West Gulf troughing allows convergence
over the lower TX coast starting on Tuesday, perhaps peaking on
Thursday.

Well below average temperatures are expected for the eastern
portion of the Lower 48 Sunday behind the trough causing the
offshore low pressure development. Rather below normal
temperatures then cross the Upper Midwest Monday and Ohio
Valley/eastern U.S. Tuesday. The ridging over the West Coast
maintains above normal temperatures Rockies and west through the
middle of next week with the focus of the anomaly shifting from
the West Coast to the Intermountain West early next week.


Jackson


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 PM EST Fri Jan 16 2026

Valid 12Z Mon Jan 19 2026 - 12Z Fri Jan 23 2026


...Deep troughing will cause chilly below average temperatures in
the East and lake effect snow early next week...

...Overview...

A very amplified pattern aloft will be in place into early next
week, with ridging over the West Coast and deep troughing over the
central and eastern U.S., with the latter causing below average
temperatures. This pattern will also be favorable for lake effect
snow that could become heavy. The trough may broaden westward mid-
and late week. Gulf moisture may return to the south-central U.S.
to Mid-South Wednesday-Thursday, with the potential for some wintry
precipitation into the Ohio Valley vicinity by Friday.


...Guidance/Predictability Assessment...

The latest 00/06Z model guidance remains in fairly decent
agreement on the overall pattern through most of next week. A
highly amplified pattern will be in place with broad upper-
troughing over the eastern to central U.S. and an upper-ridge along
the West Coast. The details of embedded short-wave energies and
associated surface systems not surprisingly get a bit more murky,
though with good clustering at least for a pair of systems
departing the East Coast early next week and around another
clipper-like system mid- week. The GFS/ECMWF as well as ECMWF AIFS
generally tended to be better clustered compared to the CMC into
mid-week, so the updated WPC forecast focused on a GFS/ECMWF/ECMWF
AIFS/CMC blend that slowly trended down the contribution from the
CMC. The ECens mean was added as a replacement given its similarity
to the deterministic guidance.

Uncertainty increases to larger-scales by the end of next week,
with disagreement on the potential for upper-wave(s) to impinge on
the upper-ridge along the West Coast, and how amplified the upper-
trough will remain over the eastern to central U.S. The 06Z GFS was
more aggressive in bringing an upper-wave over the eastern Pacific
southward over the West Coast and to the southwestern U.S. while
the 00Z ECMWF/CMC were slower and weaker as the energy splits with
a potential cutoff low developing off the West Coast. The means
tended to favor the phasing of the ECMWF/CMC, and the 12Z GFS came
in more similar to the other guidance. Further east, the GFS has
been alternating between the upper-trough remaining more amplified
with stronger high pressure over the eastern U.S., or retreating a
bit north and allowing warmer air/moisture further north. The ECMWF
has alternated a bit as well, but remains more amplified with
stronger high pressure in place. The ensemble means not
surprisingly land somewhere in the middle, with the latest GEFS
mean actually more similar to the ECMWF than the ECens, though they
both maintain a similarly more amplified trough and higher
pressure further south, particularly closer to the East Coast. The
AI guidance (AIGFS/ECMWF AIFS) were also similar in this fashion,
with the combo of the means and AI guidance supportive of any QPF
more focused over the Ohio/Tennessee Valleys. The NBM QPF was a bit
higher than other guidance, though maintained a similar footprint,
with the GFS much wetter and ECMWF drier. For this part of the
period, the updated WPC forecast used the GEFS/ECens means (up to
65% of the blend), with the removal of the GFS and favoring the
ECMWF AIFS over the ECMWF.


...Weather/Hazards Highlights...

Several days of lake effect and upslope flow snow are in store
with the mean westerly wind pattern across the northeastern
quadrant of the lower 48. The heaviest snow is generally likely
Monday-Tuesday, though with more possible Wednesday-Thursday.
Several inches of snow could eventually pile up to 1-2 feet in
western New York downwind of Lake Ontario. Additionally, a clipper
system could spread snow across portions of the Dakotas into the
Upper Midwest particularly on Tuesday.

Dry weather persists elsewhere on Monday, but by Tuesday Gulf
moisture may make it into southern Texas in particular and pool
along a front. There is some model spread with when any notable
rain may form, so there remains no excessive rainfall area there
for Day 5/Tuesday. There continues to be a much greater signal for
heavy rainfall (amounts locally as much as 2-4") into Wednesday
focused along the Western Gulf Coast, though with less certainty on
potential impacts given the lack of recent rainfall and dry
antecedent conditions. Some rain could spread east or northeast
into Thursday, across the Mid- South or Southeast. Then, into
Friday, a focus of precipitation across the Ohio Valley and
potentially into the Mid-Atlantic could bring winter-weather
concerns (snow and/or ice), though much uncertainty remains on both
amounts and where the transition zone to wintry precipitation
would set up. Additionally, the Pacific Northwest to Intermountain
West could see increasing precipitation for Wednesday into Thursday
depending on the uncertain pattern aloft.

Well below average temperatures are expected across the Midwest
Monday, with lows in the negatives and highs in the single digits
and possibly even staying below 0 in some locations, which is 15 to
25 degrees below normal. Meanwhile below average temperatures by
10 to 15 degrees are forecast across the Southeast Monday and
Tuesday, which could meet hazardous thresholds for cold weather.
Colder than normal temperatures should slowly march east on Tuesday
and Wednesday, across the Southeast to Ohio Valley and then the
Eastern Seaboard. Chilly temperatures are forecast to persist for
the northern tier into late week, but the central to southern tier
may moderate as warmer than average temperatures from the West
spread eastward.


Putnam/Tate


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
230 PM EST Sat Jan 17 2026

Valid 12Z Tue Jan 20 2026 - 12Z Sat Jan 24 2026


...Deep troughing will cause chilly below average temperatures in
the eastern and northern U.S. and lake effect snow...

...Overview...

It remains the case that a very amplified pattern aloft will be in
place as the period begins Tuesday, with ridging over the West
Coast and deep troughing over the central and eastern U.S., with
the latter causing below to much below average temperatures. This
pattern will also be favorable for lake effect snow that could
become heavy. The trough may broaden westward later next week
while becoming shallower to the east. Gulf moisture is forecast to
return to the south-central U.S. and toward the Mid-South
Wednesday-Thursday, and then there is uncertain potential for some
organized wintry precipitation in the Middle Mississippi to Ohio
Valley into Friday-Saturday to monitor given cold Canadian frontal
surge and lead return flow.


...Guidance/Predictability Assessment...

The 06 UTC GFS and 00 UTC ECMWF/UKMET/Canadian model solutions seem
reasonably well clustered valid for Tuesday into Thursday and a
composite blend seems to provide a solid forecast starting point
generally in with WPC product continuity in a pattern with above
normal predictability. Added GEFS/ECMWF/Canadian ensemble means to
the model mix into next Friday/Saturday to better mitigate embedded
system variances consistent with individual predictability.
Uncertainty does also grow during these longer time frames given
the AIFS ensemble mean and Graphcast/Aurora machine learning models
show a recent trend to shift the longer wave pattern more
progressively eastward with time than the standard models and
ensembles. However, the Pango and FourCast machine learning models
are more in line with the aforementioned WPC favored blend. Will
hold there for now as the pattern seems slow to progress upstream
to me and the latest 12 UTC model suite has also held course.

...Weather/Hazards Highlights...

Several days of lake effect and upslope flow snow are in store
with the mean westerly wind pattern across the northeastern
quadrant of the lower 48. A clipper system could spread light snow
to the Dakotas and Upper Midwest on Tuesday and enhance Great Lakes
snow into Wednesday/Thursday, and then potentially spread into the
Interior Northeast on Thursday. Snow is forecast to be heaviest in
western New York downwind of Lake Ontario from the lake
effect/enhanced snow, as several inches of snow per day could
eventually pile up to 1-2 feet.

Late Tuesday and especially by Wednesday, Gulf moisture is
forecast to make it into southern Texas in particular and pool
along a front. It is uncertain how much instability could reach
inland, and some model guidance shows the instability and thus
heaviest rain rates remaining offshore. So while the Texas to
western Louisiana coast should see some rain, continue to hold off
from issuing an excessive rainfall area on the Day 5/Wednesday ERO
because of the uncertainty and because flooding impacts may not be
likely due to the dry antecedent conditions. Will continue to
monitor. Moderate rain is forecast to spread into the Ark-La-Tex to
Lower Mississippi Valley Wednesday and possibly some to the Mid-
South and/or Southeast into Thursday. Then into Friday-Saturday,
precipitation could spread across the Mid-Mississippi and Ohio
Valleys, including potential for winter weather with snow and/or
ice. There is ample uncertainty with precipitation coverage, types,
and amounts at this point though, so stay tuned for forecast
updates. Meanwhile, areas of the Northwest could see increasing
precipitation into later next week with energy aloft passage.

Well below average temperatures are expected across the east-
central U.S. Tuesday, with lows in the single digits likely
reaching as far south as Kentucky and east to Pennsylvania, and
lows below -10F in the Upper Midwest. Chilly temperatures should
track into the Eastern Seaboard on Wednesday while moderating. Then
repeated rounds of reinforcing troughing are forecast across the
northern tier, leading to below average temperatures in the
northern Plains to Upper Midwest by Friday and especially Saturday,
when even highs may stay under 0F. Meanwhile, near to above
average temperatures are forecast across the West into midweek, but
with uncertainty after that dependent on the pattern aloft.

Tate/Schichtel


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
129 PM EST Sun Jan 18 2026

Valid 12Z Wed Jan 21 2026 - 12Z Sun Jan 25 2026


...Persistent upper level troughing will keep frigid temperatures
in place for the north-central U.S. through next weekend...

19Z Update: The 12Z model guidance suite features good overall
synoptic scale agreement through Thursday across the Continental
U.S., with a general model blend used for fronts and pressures
through that time. The 12Z GFS starts diverging from the consensus
by Friday and into the weekend with the upper low farther east
near southern California, in contrast to the more offshore 6Z GFS
and non-NCEP guidance. There are also differences with frontal
boundary latitudinal placement across the southern Plains by
Saturday, with the 12Z GFS coming into better alignment compared to
the more northern 6Z placement. Model confidence and run-to-run
continuity suffers more by Sunday with the extent of upper level
troughing across the Midwest/Great Lakes/Northeast, with an
ensemble mean approach a suggested starting point. In terms of the
NBM, the majority of the deterministic guidance was a little lower
with temperatures across the central and eastern U.S. for the
second half of the forecast period, so the NBM was blended with
about half of the slightly colder auto blend, with most readings
about 1-3 degrees lower than NBM as a result. There was a slight
increase in QPF for lake effect snows, and a modest decrease from
the widespread heavier QPF from the NBM extending from the ArkLaTex
to the Mid-Atlantic to be more in line with the deterministic
consensus. The previous forecast discussion is appended below.

Hamrick
------------------------

...Overview...

An amplified pattern aloft will be in place midweek, with ridging
over the West Coast and deep troughing over the central and eastern
U.S., with the latter causing below average temperatures. This
pattern will also be favorable for lake effect snow that could
become heavy. The trough may broaden westward mid- and late week
while becoming shallower to the east. Gulf moisture is forecast to
return to the southeastern quadrant of the U.S. Wednesday-Thursday.
Then precipitation could overspread much of the eastern half of
the U.S. Friday and into next weekend, including uncertain
potential for organized wintry precipitation across the Middle
Mississippi to Ohio Valleys and possibly the Northeast. Also Friday
into the weekend, another round of upper troughing and Arctic
surface high pressure will expand into the north-central U.S. and
bring bitterly cold temperatures well below 0F to the northern
Plains and Upper Midwest.


...Guidance/Predictability Assessment...

Model guidance is in good agreement for the large amplified trough
for areas east of the Rockies into Wednesday, with ridging atop
the West Coast. Model consensus is increasing with the energy
moving through the base of the trough across the northern Plains
early Wednesday and the Ohio Valley early Thursday, for better
agreement in frontal timing and precipitation distribution compared
to a day ago (though possibly multiple waves of fronts make it
tricky). As this energy lifts out late week, the trough should
flatten and lead to more zonal flow across the south. By Saturday
there is some model spread with the primary upper low embedded
within the northern stream--the 00Z ECMWF seems alone for the
deterministic models in bringing it east into southeast
Canada/northeastern U.S. while other models keep it near James Bay
--but the EC-AIFS is similar to the ECMWF. This would have
implications on precipitation distribution including winter weather
in the Ohio Valley to Northeast late week into the weekend for
example.

Meanwhile there remains a fair amount of model spread by later
week with northern stream energy digging into the Northwest, plus
the possibility of interaction with a southern stream eastern
Pacific upper low. The primary outlier was the 12Z GFS, which
showed a faster southern stream low track combined with stronger
northern stream energy for phasing a deep trough in the West over
the weekend, unlike other guidance and the 18Z and now 00Z GFS.
Other than that, it becomes difficult to pick out any outliers as
multiple shortwaves may develop troughing in the West, but with
uncertainties in depth and timing of the trough. Over the weekend
the new 00Z GFS moves troughing farther east quickly. It jives
relatively well with the EC-AIFS, while the AIGFS on the other hand
shows troughing across the Interior West and looks more like the
deterministic ECMWF, demonstrating the spread.

Overall, the WPC forecast was based on a multi-model blend early
in the period, with increasing proportions of ensemble means as the
period progressed and spread increased.


...Weather/Hazards Highlights...

Several days of lake effect and upslope flow snow are in store
with the mean westerly wind pattern across the northeastern
quadrant of the lower 48. A clipper system could enhance Great
Lakes snow into Wednesday-Thursday and spread lighter snow to the
Northeast Thursday. Snow is forecast to be heaviest in western New
York downwind of Lake Ontario from the lake effect/enhanced snow;
after likely heavy snow amounts Tuesday (now in the short range
period), several more inches of snow on Wednesday and Thursday are
possible, potentially piling up to 1-3 feet.

Gulf moisture is forecast to reach southern Texas into the Lower
Mississippi Valley on Wednesday and pool along a front, producing
moderate to possibly heavy rain. A Marginal Risk of excessive
rainfall has been introduced for portions of southeast Texas into
southwestern Louisiana on Day 4/Wednesday, where recent model
guidance is depicting the potential for some 1-2+ inch rainfall
totals, which could be enough to cause mainly nuisance level urban
flooding if this happens in a shorter period of time. The
mitigating factor will be the limited inland extent of higher
instability, with most of it remaining over the coastal waters.
Moderate rain is forecast to spread into the Ark- La- Tex to Lower
Mississippi Valley Wednesday and across the Gulf Coast into Florida
on Thursday, but with rain amounts well below any excessive
rainfall threat. Then for Friday, another round of precipitation is
forecast to spread across the Lower/Middle Mississippi Valley into
the Tennessee and Ohio Valleys and move east into next weekend.
Northern areas of this precipitation shield like the Mid-
Mississippi and Ohio Valleys into the Northeast could see winter
weather as moisture overruns incoming cold air. Snow and/or ice are
both possible, but there is ample uncertainty with precipitation
coverage, types, and amounts at this point, so stay tuned for
forecast updates. Meanwhile, the Pacific Northwest into the
northern Rockies can expect increasing precipitation Thursday and
persisting into Friday-Saturday due to energy aloft.

Below average temperatures are expected across the eastern U.S.
Wednesday, particularly with chilly morning lows. Elsewhere
temperatures should be generally near to slightly above average for
midweek. Then repeated rounds of reinforcing troughing are
forecast across the northern tier into late week, while a cold
surface high sinks in from Canada and pushes a strong cold front
south across the Plains and vicinity. By Friday, the northern
Plains to Upper Midwest should see well below average temperatures,
where even highs may stay under 0F. Over the weekend, the cold is
forecast to remain across the northern tier and spread south across
much of the central U.S. and east into the Great Lakes/Northeast.
There is uncertainty in how far south the cold front reaches after
a warmer than average spell in the southern Plains Friday and the
Southeast Saturday.


Tate/Hamrick


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw