509
FXUS02 KWBC 012000
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Sun Mar 1 2026

Valid 12Z Wed Mar 04 2026 - 12Z Sun Mar 08 2026

...Emerging East-Central U.S. Heavy Rainfall Pattern this week...


...Guidance/Predictability Assessment...

Guidance uncertainty in the upcoming medium-range period begins
primarily focused across the Plains and vicinity mid-later week.
Recent GFS/GEFS continues to advertise a frontal wave to track
northeastward across the Midwest. This solution remains more
amplified than the rest of the dynamical solutions that dig energy
more sharply through the West. The AI models favor a delayed
amplification relative to the GFS/GEFS but they have come into
better agreement today. The ECMWF remains the least amplified
guidance regarding this wave. Thereafter, another upper-level
trough/wave is now more uniformly forecast in guidance to dig more
through the West to the Southwest/Baja next weekend, but also
allow for renewed Gulf return flow downstream in channeled flow on
the western to northern periphery of a building/warming Southwest
U.S./Atlantic upper trough. This will set another stage for the
next bout of high QPF into next weekend from the south-central
Plains to the Midwest in a region having just experienced
widespread rainfall/convection.


...Weather/Hazards Highlights...

A pronounced split upper flow pattern will dominate the nation this
week. A leading southern stream upper trough and surface system
will eject from the south-central U.S. through the Midwest then
Northeast mid-late week and return inflow will fuel an emerging
area of moderate to heavy rains/convection under a favorable upper
jet. The Day 4 & 5 (Wednesday/Thursday) WPC Excessive Rainfall
Marginal threat areas were reduced given the focus of highest QPFs
is now across the southern Plains to the Mid-Mississippi Valley
based on the latest from guidance. 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 a swath of snow from northern portions of the Upper
Midwest/Great Lakes to the Interior Northeast where conditions may
also support an icy transition zone to monitor.

Meanwhile upstream, an amplified upper trough will dig sharply
southeastward into the West from the Pacific Northwest to the
Southwest/Rockies Wednesday-Friday and bring unsettled and cooling
flow along with a widespread moderate precipitation focus from the
Pacific Northwest through the north-central Intermountain/Rockies
to include terrain enhanced snows. While recent guidance trends dig
an increasing southern stream detached upper low/trough through
the Southwest into Baja next weekend, downstream energy translation
should also act to renew the wet/convective flow pattern next
weekend again over the south-central U.S. to Midwest to monitor for
runoff issues given ample earlier rainfall to moisten soils.
Additional flow from the northeast Pacific may also work back into
the Northwest to renew moderate precipitation next weekend and
continued northern stream energy translation into cyclonic upper
flow downstream into the northern tier could also allow for some
cooler airmass intrusions to interact with the northern fringe of
the aforementioned expanding southern stream precipitation area.

In this pattern, amplified Southeast/Atlantic upper ridging and
significant springtime warming will build and linger up the East
Coast through later next week/weekend as lead cold damned high
pressure moderates and loses southward influence.


Kong/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

















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