716
FXUS21 KWNC 301736
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT August 30 2025

SYNOPSIS: Late in week-1 into the outset of week-2, dynamical models are in
good agreement regarding a robust area of mid-level low pressure developing
across the Great Lakes and Northeast. This feature is likely to bring weather
more typical of early Fall. As surface high pressure builds over the Northeast,
enhanced easterly flow is favored across the Southeast, with a wavering frontal
system contributing to periods of unsettled weather across the Gulf and
Southeast Coasts including Florida. Over the Southwest, potential tropical
cyclone development west of Mexico could enhance tropical moisture, increasing
the potential for episodes of locally heavy precipitation for the region early
in the period.

HAZARDS

Slight risk of heavy precipitation across Florida, the Gulf Coast, and coastal
portions of the Carolinas and Southeast, Mon-Sat, Sep 8-13.

Slight risk of heavy precipitation across parts of the Desert Southwest,
Sun-Mon, Sep 7-8.

Slight risk of high winds across portions of the coastal Southeast, Florida,
and the Gulf Coast, Tue-Sat, Sep 9-13.

Slight risk of much below normal temperatures across portions of the Upper
Mississippi Valley and Great Lakes, Sun, Sep 7.

DETAILED SUMMARY

FOR TUESDAY SEPTEMBER 02 - SATURDAY SEPTEMBER 06:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR SUNDAY SEPTEMBER 07 - SATURDAY SEPTEMBER 13: Late in week-1, a highly
amplified 500-hPa height pattern is predicted across North America, with strong
ridging across the Gulf of Alaska and western Canada, and troughing downstream
over the eastern U.S. These features are forecast to persist into the beginning
of week-2 before slowly weakening. The ridging over western North America
favors anomalous warmth across the Northwest, with extreme heat concerns prior
to the start of week-2. While above-normal temperatures are still likely during
week-2, the signals for extreme heat diminish compared to the late week-1
timeframe. Nonetheless, anticipated hot and dry conditions may lead to enhanced
wildfire risk across interior portions of the Northwest and northern California.



Downstream over the north-central and northeastern CONUS, the amplified trough
moving across the region will bring a noticeable cool-down after frontal
passage and associated precipitation which is likely to move through prior to
week-2. Behind this front unseasonably cold air temperatures are depicted by
model ensembles. In particular, the ECENS PET depicts probabilities exceeding
20 percent for minimum temperatures in the lowest 15th climatological
percentile and below 40 deg F over much of the Upper Mississippi Valley, Great
Lakes, and into parts of the Interior Northeast. The GEFS PET is not quite as
bullish as the ECENS but still indicates at least a 20% chance of minimum
temperatures below 40F at the outset of week-2. Todays forecast maintains the
slight risk of much below normal temperatures over portions of the Upper
Mississippi Valley and Great Lakes, Sep 7, where the coldest temperatures are
predicted. While it is uncertain the extent of areas that will drop below 40
deg F, any isolated areas that dip into the 30s deg F could be at risk for
frost over susceptible vegetation. Nighttime temperatures are also favored to
be unseasonably cool for much of New England. Isolated areas of frost and even
freezing conditions in higher elevations are possible early in week-2, however
confidence in this outcome is low and affected areas are generally sparsely
populated therefore no associated hazard is posted at this time.



The aforementioned front is forecast to become quasi-stationary across the Gulf
Coast and Southeast during week-2, with surface high pressure over the
Northeast leading to enhanced easterly flow across the Southeast. As a result,
unsettled weather is likely over these areas throughout the period, in the form
of episodic heavy precipitation and potentially elevated wind speeds.
Uncalibrated guidance from the 0z ECENS and GEFS generally depicts the heaviest
precipitation amounts just offshore, but it would not take much of a shift to
bring these higher totals to the coast. The GEFS and ECENS PETs depict at least
a 20 percent chance of 3-day precipitation totals exceeding the 85th percentile
and 1-inch along the Gulf and Southeast coasts for much of week-2. Initially
the strongest signals are depicted across southern Texas before spreading
eastward across to the entire Gulf Coast and up the southern Atlantic coast by
the middle of the period. Todays model solutions are a little slower with the
development of the heaviest rain and enhanced winds but then favors a quick
eastward spread, therefore a slight risk of heavy precipitation is posted over
all of these areas for Sep 8-13. Additionally, the ECENS and GEFS 10m wind
speed forecasts indicate enhanced winds to develop over the  eastern Gulf and
up the Southeast coast, shortly after the onset of heavy precipitation, with
episodic enhanced winds of 20mph or more along the coast supporting a slight
risk of high winds for the Gulf coast east of New Orleans, across Florida and
up the Atlantic coast to the Outer Banks for Sep 9-13.



Tropical cyclone development is likely across the East Pacific during the next
week, with the potential of at least one system to track northwestward, with
the ECENS tracking closer to Baja California and the GEFS farther offshore. A
more northerly component of the track is likely to enhance moisture over parts
of the Southwest leading to elevated chances of heavy precipitation. Despite
high uncertainty of the timing and possible impact of enhanced moisture from
possible tropical cyclones, a slight risk of locally heavy precipitation is
highlighted for parts of Arizona and southwestern New Mexico, Sep 7-8,
primarily based on guidance from the PETs.

FORECASTER: Danny Barandiaran

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