Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
340 PM EDT Thu Mar 12 2026

Valid 12Z Sun Mar 15 2026 - 12Z Thu Mar 19 2026


...Record warmth across California and the Southwest this weekend
into next week...

...Strong storm to bring heavy snow and high winds for the Upper
Midwest/Great Lakes...


...Overview...

The medium range period will trend quite amplified into next week.
A shortwave digging into the north-central U.S. on Sunday will
spin up a reasonably strong surface low in the central U.S.,
tracking into the Great Lakes on Monday. Heavy snow and strong
winds remain likely Sunday-Monday for the Upper Midwest into the
Upper Great Lakes. Gusty winds and modest rainfall will accompany
the cold front through the East as well. Meanwhile, an extremely
strong upper-level ridge centered over the Southwest and Great
Basin will promote unseasonably warm to record-breaking
temperatures across California to the Southwest and eventually into
parts of the Intermountain West.


...Guidance/Predictability Assessment...

Model guidance continues to show good agreement on the large scale
pattern evolution featuring an amplified trough over the East and
strong ridging over the West. The low deepening as it tracks across
the Mid-Mississippi Valley Sunday into the Great Lakes early
Monday has reasonable consensus, with mainly minor spread. Among
the 12Z guidance, the ECMWF and AIFS seem to show the best middle
ground between the farther east AIFS and slightly slower/southwest
GFS/CMC with the low position 12Z Monday. The 12Z CMC appears on
the slow side to move the cold front across the East Monday-
Tuesday. After that, the stagnant pattern should remain across the
CONUS with good agreement, though there is some minor spread for
the late period with the trough in the East
lifting/weakening/slowly moving east. Regardless, the reasonable
model agreement allowed for the WPC forecast to favor a
deterministic model/AIFS forecast through the period, with some
minority ensemble mean inclusion by late in the forecast to account
for smaller scale variances in the deterministic guidance.


...Weather/Hazards Highlights...

A storm system moving into the Central U.S. on Sunday will spin up
into a reasonably strong surface low over the Great Lakes by
Monday. This will bring a heavy snow and high wind threat in the
Upper Midwest and Upper Great Lakes Sunday into Monday, with
increasing confidence in blizzard or near-blizzard conditions in
some locations. Over a foot of snow is likely across portions of
Wisconsin and Michigan, and over two feet of snow is possible. A
corridor of freezing rain is also possible just south of the snow.
Rain with this system ahead of the cold front should stay fairly
modest across the southeastern quadrant of the U.S. Sunday, but
severe weather is possible centered over the Lower Mississippi
Valley per the Storm Prediction Center. Rain and thunderstorms are
forecast to move into the Eastern Seaboard Monday. Severe weather
is most likely in the Southeast, but the heaviest rainfall amounts
may occur over the Northeast as multiple rounds of rainstorms move
in ahead of and with the cold front. Climatological percentiles of
integrated vapor transport are near the max for March in the
Northeast, so WPC continues to highlight a Marginal Risk Day
5/Monday in the Excessive Rainfall Outlook over much of the
Northeast. Gusty winds may accompany this system as it tracks
through the East. Some lake effect snow is possible downwind of the
Great Lakes behind the low as well.

Meanwhile, a couple of shortwaves could keep the Pacific Northwest
fairly wet through the period. A plume of moisture will be
persistent into British Columbia next week, but with less
confidence on how far south precipitation will occur. The Olympics
and northern Cascades can expect at least modest totals, but will
continue to hold off on any ERO areas due to uncertainties in the
rain's southward extent, snow levels, and rainfall rates. Moderate
to heavy snow is possible in the higher elevations of the Northwest
inland into the Rockies. Elsewhere, some light rain and snow may
spread across the north- central U.S. by Monday-Wednesday with a
shortwave impulse and surface front.

Heat from California/the Southwest to the central Great Basin will
build through the period. Moderate to localized Major HeatRisk is
forecast across parts of Southern California into the Desert
Southwest as temperatures approach or exceed 100 degrees in some
places. Widespread record-breaking warm daily maximum and minimum
temperatures are likely, and even some March records could be
tied/broken as these temperatures are more typical of the summer
months. Pre-frontal warm temperatures are forecast across the South
into the Ohio Valley Sunday and the Northeast on Monday, but these
will be replaced by colder temperatures behind the amplifying
upper trough and strong cold front. Daytime highs are forecast to
be 10 to 20 degrees below average over the north-central U.S. by
Monday and reaching the east-central U.S. Tuesday, and chilly
morning lows may lead to frost/freeze concerns in the Southeast.
However, temperatures are forecast to rebound to well above average
across the Plains for mid and late week as the western upper ridge
expands.


Tate/Santorelli


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