Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
235 AM EST Sun Jan 18 2026

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


...Rounds of troughing will bring much below average temperatures
to the north-central U.S. especially by late week/next weekend...

...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, 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. Model guidance is currently
indicating that most instability in the vicinity will remain
offshore, limiting higher rain rates. If instability does reach the
immediate coast, heavy rain would fall over areas of sandy soils
that are not sensitive, plus the whole region has dry antecedent
conditions. Thus continue to hold off on any excessive rain areas
for the Day 4/Wednesday ERO, though the flooding threat could be
nonzero especially if higher rain rates reach urbanized areas like
Houston. 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


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