440
FXUS02 KWBC 021928
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
228 PM EST Mon Mar 2 2026

Valid 12Z Thu Mar 05 2026 - 12Z Mon Mar 09 2026

...Heavy rain/flooding and severe weather expected in the south-
central U.S. late week into the weekend...


...Overview...

Shortwave energy will move through the Northeast Thursday-Friday
and promote precipitation including wintry weather there. Behind
this feature, broader troughing is forecast to dive through the
interior West late week and split off a southern stream upper low
near northern Mexico by the weekend. This pattern will advect ample
moisture and instability into the central U.S. and produce
widespread thunderstorms with severe and flooding potential.
Additionally, expect unseasonably warm temperatures in the eastern
half of the U.S. under downstream upper ridging.


...Guidance/Predictability Assessment...

Model guidance, especially the incoming 12Z model suite, is in
rather good agreement with the overall pattern described above. The
most uncertain aspect of the pattern has been where the southern
stream closed upper low will set up. During the 00/06Z model cycle,
the CMC and the 00Z GFS were on the faster/more phased side with
the upper low, while the 00Z ECMWF was quite slow. The 06Z GFS as
well as the AIFS/AI-GFS provided a good middle ground. Now at 12Z,
the CMC has slowed and the EC has sped up, providing better timing
confidence. Shortwaves in the northern stream show some typical
differences that could affect frontal positions, but without
notable outliers. Thus could maintain a majority of
deterministic/AIFS guidance for the forecast period, with some
inclusion of the ensemble means by the late period. The 13Z NBM
worked well for most fields.


...Weather/Hazards Highlights...

A lead shortwave trough and frontal system will eject through the
Midwest then Northeast Thursday/Friday and pooling moisture may
fuel areas of moderate rains. Overrunning moisture into cold
Canadian high pressure sliding into the U.S. northern tier as
driven by more progressive northern stream energies should also
support some snow from northern portions of the Upper Midwest/Great
Lakes to the Interior Northeast where conditions also support an
ice/freezing rain transition zone to monitor.

Upstream, an amplified upper trough will dig sharply southeastward
through the West into Thursday/Friday and bring unsettled and
cooling flow along with a widespread moderate precipitation focus
out from the Pacific Northwest through the north-central
Intermountain/Rockies to include terrain enhanced snows. A split
upper flow pattern should become dominant as this energy separates
into the southern stream and stalls near Baja California into the
weekend. With the western trough and upper low pattern, Pacific and
Gulf moisture will flow into the central U.S. along with
instability, while a wavy front is in place. Runoff threats may
build with each round of rain given a repeating pattern with some
cell training potential. A Marginal Risk of excessive rainfall for
flooding/runoff threats remains in place for portions of the south-
central Plains into the Mid-Mississippi Valley Day 5/Friday with a
protracted wet period at least through this weekend to monitor. SPC
is also highlighting similar areas for severe potential. More
modest precipitation should spread into the Northeast, mostly in
the form of rain, though the northern fringe may see wintry
weather.

In this pattern, amplified Southeast/Atlantic upper ridging
significant springtime warming will build over the central and
eastern U.S. late week, lasting in the East into early next week.
Temperatures will be 20-30 degrees above average, with 80s reaching
as far north as parts of the Ohio Valley and Mid-Atlantic. Daily
records could become widespread.


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




$$