349
FXUS21 KWNC 031755
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT April 03 2025

SYNOPSIS: Mid-level low pressure is forecast across the eastern contiguous U.S.
(CONUS) early in week-2, with dynamical models continuing to indicate an area
of surface low pressure forming along the Eastern Seaboard bringing enhanced
chances of heavy precipitation to portions of the Mid-Atlantic and Northeast.
While below-normal temperatures continue to be likely across much of the East
during the first half of the period, relatively warmer temperatures are likely
compared to the late week-1 period, and it is less likely minimum temperatures
will cause any additional impacts to vegetation. Mid-level high pressure is
forecast to shift across the central CONUS, with models trending stronger with
mid-level low pressure upstream across the Northwest. This favors increasing
pressure gradients and elevated wind speeds across much of the Great Plains and
Upper and Middle Mississippi Valley, which in combination with above-normal
temperatures and dry soils, may increase the wildfire risk over some of these
areas.

HAZARDS

Slight risk of heavy precipitation across coastal portions of the Northeast and
Mid-Atlantic, Fri-Sun, Apr 11-13.

Slight risk of high winds across portions of California, Fri-Mon, Apr 11-14.

Slight risk of high winds across much of the Great Plains and Upper and Middle
Mississippi Valley, Sat-Mon, Apr 12-14.

DETAILED SUMMARY

FOR SUNDAY APRIL 06 - THURSDAY APRIL 10:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR FRIDAY APRIL 11 - THURSDAY APRIL 17: Troughing is forecast to reload across
the eastern CONUS early in week-2. As a result, below-normal temperatures are
likely to persist through the first half of the period. However, minimum
temperatures are forecast to be warmer compared to late in week-1, with the
uncalibrated 0z GEFS and ECENS depicting areas with susceptible vegetation
remaining above 40 deg F. Therefore, the much below-normal temperatures hazard
is discontinued across the East.



Models continue to depict a wave of surface low pressure developing along the
East Coast ahead of the trough at the start of week-2. The ECENS and GEFS
Probabilistic Extremes Tools (PETs) depict at least a 20 percent chance 3-day
precipitation totals exceed the 85th climatological percentile along the
Eastern Seaboard north of the Carolinas, with probabilities for precipitation
totals exceeding 1-inch only exceeding 20 percent over parts of coastal New
England. However, the uncalibrated 0z ECENS depicts these enhanced
probabilities extending further inland across New England and the coastal
Mid-Atlantic. While the potential is marginal, a slight risk of heavy
precipitation is posted for coastal portions of the Northeast and Mid-Atlantic,
Apr 11-13. The 0z and 6z deterministic GFS solutions depict a more robust
surface low compared to the ensemble means. These stronger solutions would
favor heavier precipitation extending further inland along with some risk for a
period of dynamically driven snow depending on the track of the low. Given the
increased uncertainty and lack of ensemble support, no related snow hazard is
posted at this time.



Compared to yesterday, the 0z GEFS, ECENS, and CMCE have all trended stronger
with shortwave troughing moving into the northwestern CONUS early in week-2,
with anomalous ridging shifting further downstream over the central CONUS.
Despite some increased onshore flow, the PETs remain unimpressive with
probabilities for hazardous precipitation. An increased risk of high winds is
more of a concern, with the PETs depicting broad areas of the western and
central CONUS having probabilities above 20 percent for wind speeds exceeding
the 85th climatological percentile and 20-mph. Synoptically, the strongest
pressure gradients are forecast to set up across the Great Plains and Upper and
Middle Mississippi Valley beginning on day-9 (Apr 12) due to surface high
pressure forecast across the Gulf Coast and surface low pressure moving into
the West. As a result, a slight risk of high winds is posted across these
areas, Apr 12-14. There is additional concern for increased wildfire potential
due to drier than normal conditions along with forecast temperatures at least
10 deg F above-normal. Additionally, an offshore flow pattern is forecast to
develop across California, with the uncalibrated 0z ECENS and GEFS depicting
high probabilities for wind speeds exceeding 20-mph just offshore. Based on
this, and the likely extension for higher winds across low elevation inland
areas, a slight risk of high winds is posted across portions of California, Apr
11-14, with wildfires again being a primary concern, especially across drier
areas of southern California.



No hazards are indicated across Alaska underneath weak troughing and a variable
temperature pattern. Slightly elevated chances for above normal precipitation
are forecast across Southeast Alaska, with near- to below normal precipitation
chances increased across the rest of the state.

FORECASTER: Thomas Collow

$$