693
FXUS21 KWNC 291912
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT July 29 2025

SYNOPSIS: Mid-level high pressure is favored to be a dominant feature over the
Contiguous U.S. (CONUS) for much of the week-2 forecast period, resulting in
generally quiet weather from a hazards perspective. Temperatures for much of
the Lower 48 are likely to be above-normal, potentially reaching hazardous
thresholds for portions of the Desert Southwest. Mid-level low pressure along
the West Coast at the outset of week-2 is favored to bring enhanced winds to
much of the Great Basin, Southern Rockies, as well as portions of the Great
Plains. A weak disturbance over the U.S.-Canada border at the outset of week-2
has the potential to bring periods of heavy precipitation to portions of the
Great Lakes, and the Ohio and Mississippi Valleys early in the forecast period.

HAZARDS

Slight risk of extreme heat for portions of the Southern Plains, Desert
Southwest, and the San Joaquin Valley, Thu-Sun, Aug 7-10.

Slight risk of heavy precipitation for portions of the Great Lakes, and the
Ohio and Middle and Upper Mississippi Valleys, Wed-Thu, Aug 6-7.

Slight risk of episodic high winds for much of the Great Basin as well as
portions of the Desert Southwest, Central and Northern Rockies, and Northern
Plains, Wed-Thu, Aug 6-7.

Slight risk of episodic high winds for portions of the Southern and Central
Plains, Wed-Thu, Aug 6-7.

Slight risk of episodic high winds for much of the Texas-Mexico border and
southeastern New Mexico, Wed-Tue, Aug 6-12.

Slight risk of high winds for coastal California from Point Conception to Cape
Mendocino, Wed-Tue, Aug 6-12.

DETAILED SUMMARY

FOR FRIDAY AUGUST 01 - TUESDAY AUGUST 05:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR WEDNESDAY AUGUST 06 - TUESDAY AUGUST 12: Ensemble solutions for 500-hPa
height anomalies from the GEFS, ECMWF, and CMCE all indicate widespread ridging
over the Lower 48 for most of the forecast period, ushering in a period of
relatively quiet, if warmer than average, weather. At the outset of week-2 a
weakening trough over the West Coast is favored to enhance daytime winds for
much of the higher elevations in the western CONUS. A slight risk of high winds
is posted for much of the Great Basin, Central and Southern Rockies, as well as
western portions of the Central and Southern Plains for Aug 6-7, where the
ECMWF Probabilistic Extremes Tool (PET) indicates at least a 20% chance of
3-day maximum winds to exceed the 85th percentile. The GEFS PET is less
bullish, confining enhanced winds primarily to the northern Great Basin, but
raw probabilistic guidance from both model ensembles indicate very high
likelihood of daytime winds exceeding 10 kts for the same period of time, after
which this threshold becomes less likely. The region is also favored for
below-normal precipitation and above-normal temperatures, the combination of
which creates a very favorable environment for initiation and rapid growth of
wildfires.



The summer subtropical surface high over the North Pacific has been quite
strong recently, which has had the potential of enhancing coastal winds typical
for this time of year. Model guidance for week-2 indicates that this
enhancement is likely throughout the forecast period. The GEFS and ECMWF PETs
both indicate very high probabilities (>60%) of winds near the California coast
exceeding 25 mph throughout week-2, therefore a slight risk of high winds is
posted for coastal portions of California from Point Conception to Cape
Mendocino for all of week-2, Aug 6-12.



Models also depict enhanced easterly winds over the western Gulf and extending
into southern Texas throughout the forecast period, associated with tropical
flow and enhanced by surface low pressure over the Great Plains. This
enhancement is greatest at the outset of week-2 where ensemble mean wind speeds
approach 20mph and extend northward away from the Rio Grande Valley and into
the Central Plains. Troughing weakens quickly so enhanced surface winds over
the Plains diminish after Aug 7, but ensemble mean daily maximum winds along
the Texas-Mexico border remain elevated throughout the week. Therefore, a
slight risk of episodic high winds is posted for much of the Texas-Mexico
border and southeastern New Mexico for all of week-2, along with a northern
extension into the Southern and Central Plains for Aug 6-7.



Weak surface low pressure is favored along the U.S.-Canada border for much of
week-2, and models are depicting enhanced precipitation for the region
surrounding the Great Lakes. The GEFS and ECMWF PETs both indicate at least a
20% probability of 3-day precipitation totals to exceed the 85th percentile and
at least 0.75 inches for Aug 6-7, therefore a slight risk of heavy
precipitation is posted for portions of the Middle and Upper Mississippi
Valley, Great Lakes, and Ohio Valley for these days.



Widespread upper-level ridging over the CONUS favors above-normal temperatures
for most of the Lower 48. The GEFS and ECMWF PETs both indicate at least a 20%
chance of maximum temperature exceeding the 85th percentile for many portions
of the CONUS, and the Northeast U.S., Southern Plains, Desert Southwest and
Great Basin are all highlighted as areas of interest. While  temperatures are
not expected to reach hazardous thresholds over the northeastern U.S., todays
model solutions indicate a stronger ridge over the Desert Southwest in the
middle of week-2 with the potential for 500hPa heights reaching as high as
600dm, as well as higher ensemble mean maximum temperatures relative to
yesterday. Therefore,a slight risk of extreme temperatures has been added to
todays outlook for portions of the Southern Plains, Desert Southwest, and the
San Joaquin Valley for Aug 7-10.

FORECASTER: Danny Barandiaran

$$