656 
FXUS01 KWBC 031735
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
134 PM EDT Sat May 03 2025

Valid 00Z Sun May 04 2025 - 00Z Tue May 06 2025

...A convoluted pattern with embedded slow-moving systems is
expected across the Lower 48, leading to prolonged periods of
unsettled weather into early next week...

...Heavy precipitation is expected across the Northern
Mid-Atlantic States and from the Southern Rockies into the Great
Basin...

Deep layer lows develop over the Ohio Valley and West Coast which
will be slow to move over the next few days. In the East, the
first of the systems is developing over the Ohio Valley.  Its cold
front makes slow progress through the Central Gulf Coast and
Southeast before stalling on Monday.  Showers and thunderstorms
with heavy rainfall, with a few thunderstorms being severe, are
expected over portions of the Southeast and Mid-Atlantic States
with this system from Saturday evening through Monday.  Rainfall
totals of 2 to 4 inches in and near portions of southeast New York
of Pennsylvania will foster a Marginal Risk of excessive
rainfall/flash flooding Saturday evening through Monday.  Because
of the persistent humidity, record warm low temperatures are
anticipated for portions of the Mid-Atlantic States on Sunday.

A separate deep layer cyclone moves through the Southwest,
bringing showers and thunderstorms Saturday evening into Monday
and higher elevation snows in the Rockies/Intermountain West.  A
moist, upslope flow along the southern Rockies should persist as a
frontal boundary lingers south of the region while unstable
showers and thunderstorms form closer to the cyclone during
daytime heating.  Isolated to scattered instances of flash
flooding will be possible across portions of eastern New Mexico,
particularly for terrain sensitive regions and area burn scars
from Saturday evening through Sunday.  On Monday as the system
moves towards the Southern Plains, a scattered instances of flash
flooding are expected across portions of northwestern Texas. 
Accumulating snow is expected for some of the higher elevations of
regional mountain ranges, most notably the Sierra Nevada Saturday
evening and then portions of the northern Rockies in Montana and
the San Juans in Colorado on Sunday and Monday. Dry antecedent
conditions, gusty winds, and comparatively low relative humidity
over southwestern New Mexico, south of the unsettled weather
covering most of the West, has prompted a Critical Risk of fire
weather conditions from the Storm Prediction Center for Sunday.

Forecast highs under the eastern deep layer cyclone will be well
below average, particularly across portions of the Midwest/Ohio
Valley, as temperatures only reach into the 50s and 60s. Forecast
highs under the western deep layer cyclone will also be well below
average,across the Great Basin Sunday, with highs in the 50s and
60s, and into the Southwest, with highs only into the 70s. In
contrast, temperatures under a building upper-level ridge between
the lows will be well above average as highs soar into the 70s and
80s across much of the northern/central Rockies and into the
northern Plains/Upper Great Lakes. Some locations along the
northern High Plains may reach the upper 80s on Sunday, upwards of
25-30 degrees above average.

Roth


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php


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