692
FXUS21 KWNC 021749
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT April 02 2025

SYNOPSIS: Mid-level low pressure across the eastern contiguous U.S. (CONUS) is
forecast to peak in magnitude late in week-1 and weaken at the outset of
week-2. This feature favors an increased risk for much below normal
temperatures coinciding with emerging springtime vegetation lingering into
day-8 (Apr 10). Following a brief moderation, mid-level low pressure is
forecast to reload across the East, potentially ushering in another round of
relatively cooler temperatures, in addition to cyclogenesis across the
northeastern U.S, although confidence remains low regarding these outcomes.
Upstream, mean mid-level high pressure is forecast to keep much of the western
CONUS free of weather related hazards.

HAZARDS

Slight risk of much below normal temperatures for portions of the eastern
CONUS, Thu, Apr 10.

DETAILED SUMMARY

FOR SATURDAY APRIL 05 - WEDNESDAY APRIL 09:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR THURSDAY APRIL 10 - WEDNESDAY APRIL 16: Amplified troughing is forecast
across the eastern CONUS late in week-1, along with an associated area of
surface high pressure across the Tennessee Valley and Southeast. While this
favors a welcome drying trend, a period of anomalously colder temperatures is
forecast, with some areas experiencing frosts or freezes coinciding with
susceptible emerging springtime vegetation. The coldest temperatures are
favored prior to the start of week-2, with moderation likely as the period
begins. However, the ECENS Probabilistic Extremes Tool (PET) continues to
depict probabilities of at least 20 percent for minimum temperatures falling
below the 15th climatological percentile across portions of the eastern CONUS
on day-8 (Apr 10), with higher probabilities (above 40 percent) across the
Southeast. Minimum temperatures potentially falling below 40 deg F support a
continuation of the slight risk for much below normal temperatures on day-8
(Apr 10) due to an enhanced risk of frost. An increase in vegetation coverage
across portions of the Ohio Valley, Mid-Atlantic, and lower Northeast is
possible due to above-normal temperatures forecast early in week-1, justifying
the northward extent of the slight risk. As the trough reloads across the East,
there are some signals for another round of potentially hazardous temperatures
across parts of the Southeast around the middle of the period. However, the
PETs are more sporadic and weaker with below-normal temperature probabilities
compared to the preceding event, with the uncertainty precluding a related
addition of the hazard at this time.



Both the 0z GEFS and ECENS depict an area of surface low pressure developing
off the northeast coast on days 9 and 10 (Apr 11-12) ahead of the reloading
trough. The GEFS is more pronounced with this feature compared to yesterday,
and both the GEFS and ECENS PETs depict at least a 20 percent chance 3-day
precipitation totals exceed the 85th climatological percentile along the
Eastern Seaboard early in week-2. However, probabilities for precipitation
totals exceeding 1-inch only exceed 20 percent over parts of coastal New
England, indicating the system may remain too far off the coast or too weak for
widespread impacts. This potential will continue to be monitored, and
associated precipitation hazards may be needed in tomorrows outlook for parts
of the Northeast depending on model trends.



Strong mid-level ridging forecast across the western CONUS during week-2 favors
unseasonably warmer and drier conditions compared to week-1, resulting in no
weather related hazards for the western CONUS for week-2. However, as the ridge
shifts slightly eastward with time, heights are forecast to trend closer to
normal near the West Coast, with a greater tendency for shortwave troughs to
move into the Northwest. The models are generally weak with these features,
with the PETs unimpressive with hazardous precipitation probabilities. While
the ECENS PET depicts elevated chances for wind speeds exceeding the 85th
climatological percentile and 20-mph across portions of the Great Basin and
Northern Plains, the synoptic set-up is not indicative of a widespread high
wind event. Therefore no related wind hazard is posted, although occasional
episodes of high winds cannot be ruled out, especially if shortwave troughing
moves closer to the area.



No hazards are indicated across Alaska underneath a variable temperature
pattern along with near- to below-normal precipitation forecast during week-2.

FORECASTER: Thomas Collow

$$