Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
313 AM EDT Thu Apr 2 2026
Valid 12Z Sun Apr 05 2026 - 12Z Thu Apr 09 2026
...Overview...
At the start of the medium range period Sunday, a low pressure
system will be pulling away from the Great Lakes into Canada, but
its associated cold front will sweep across the Eastern Seaboard to
Gulf Coast for widespread rain and thunderstorms. Cooler
temperatures and some areas of rain/snow are likely behind this
system in the Midwest to Great Lakes region early next week as
energy feeds into an upper trough. Meanwhile an upper ridge is
forecast to set up over the West and cause above average
temperatures, migrating eastward as the week progresses. Behind it,
another trough/low will reach the West around midweek, leading to
increased precipitation chances there.
...Guidance/Predictability Assessment...
Model guidance has been persistent and agreeable with the upper
and surface low exiting the U.S. into southeastern Canada by
Sunday, though with troughing maintaining itself in the Great Lakes
to Northeast and southward into early next week as a steady stream
of vorticity feeds southeastward on its western side. Ridging
upstream across the western U.S. Sunday seems rather predictable
and is forecast to gradually shift east into the workweek.
Behind the ridge, models continue to show a fair amount of
variability with two upper troughs/lows: one moving from the Gulf
of Alaska southeast into Canada, and one farther south moving
through the open Pacific around 35-40N latitude toward the West
Coast. Regarding the latter, GFS runs have been faster/farther east
compared to the EC/CMC, but was skeptical of how slow the 12Z
EC/CMC were, given the EC-based AI models were faster. The 00Z
models have converged a bit toward a preferred middle ground of
reaching the West Coast around Wednesday, but still exhibit this
pattern of a fast GFS/slow EC especially. With the northern upper
low, individual models vary considerably with its position and
strength with no clear consensus. These lows may have some level of
interaction with each other depending on their positions. It will
likely take additional time to resolve these model differences
given their origins from relatively data-sparse regions.
The WPC forecast used a multi-model blend for the early part of
the forecast period. Given the increasing spread out West later
period, increased the proportion of ensemble means in the blend to
near half Day 7. Also used a healthy portion of the AIFS as a good
middle ground for the western low positions.
...Weather/Hazards Highlights...
A cold front will stretch through the Eastern Seaboard and back
west across the Gulf Coast on Sunday, with moisture pooling ahead
of it. Rain and thunderstorms are forecast to push through the East
pretty quickly, with the fast frontal movement likely precluding
too many flooding concerns. The exception could be on the western
side of the front back into southern Texas, where there is a chance
for multiple rounds of convection in an unstable airmass along the
front. Will raise a Marginal Risk for Day 4/Sunday in the ERO for
possible isolated flooding in South Texas. By Monday, the front is
forecast to push offshore of most land areas into the Atlantic and
Gulf, though it will still be passing over Florida and provide a
focus for above average moisture there. Will hold off on any
excessive rainfall areas there for Day 5/Monday though, due to
concerns about the heaviest convection possibly staying offshore,
but Florida is worth monitoring for potential flash flooding
concerns. A wet pattern should persist across Florida Tuesday and
Wednesday as southern stream energy comes across.
Farther north, the mean westerly flow in the eastern trough into
early next week will allow for some lake effect precipitation. Then
at least one round of rain and snow should move through the Upper
Midwest across the Great Lakes region Sunday-Monday and possibly
lasting in the northern Mid-Atlantic/Northeast on Tuesday. Another
swath of precipitation is possible in the north-central Plains to
Mid-Mississippi Valley. Meanwhile, convection is possible in the
Four Corners region Sunday-Tuesday with some southern stream waves
aloft and above average moisture. Then as an upper low/trough moves
toward and into the West, it will provide lift for precipitation
in the Pacific Northwest/northern California to northern Rockies by
Tuesday and more of the Intermountain West Wednesday, including
higher elevation snow. Some precipitation could stretch into the
Plains and Midwest midweek as well, but with more uncertainty.
A warm Sunday morning is in store for the Eastern Seaboard before
the cold front comes through. This front will yield chillier
temperatures that are generally slightly below average across parts
of the central to eastern U.S. through the first half of next
week. On the other hand, the West can expect above average
temperatures by 10 to 20 degrees underneath upper ridging for the
early part of the week. Above normal temperatures should spread
into the High Plains by Tuesday and gradually farther east
Wednesday and Thursday as the ridge pushes east, while the West
Coast can expect temperatures to cool once again.
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
