679
FXUS21 KWNC 261848
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT September 26 2026

SYNOPSIS: A cold front is forecast to shift southward across the East and Gulf
Coasts early in week-2, with an elevated risk of heavy precipitation. Behind
this cold front, at least a brief period of cooler-than-normal temperatures are
expected to overspread much of the central and eastern Contiguous U.S. (CONUS).
There is an increasing chance of the first widespread frost or freeze of the
season for the Great Lakes region and interior Northeast. A series of low
pressure systems with enhanced onshore flow results in a slight risk of heavy
precipitation and high winds for southcentral and southeastern Alaska.

HAZARDS

Slight risk of heavy precipitation for much of the East and Gulf Coasts,
Sun-Tue, Oct 4-6.

Slight risk of heavy precipitation for the Florida Peninsula, Sun-Sat, Oct 4-10.

Slight risk of much below normal temperatures for most of the Great Lakes
region and interior Northeast, Sun-Wed, Oct 4-7.

Slight risk of heavy precipitation for parts of southcentral and southeastern
Alaska, Sun-Sat, Oct 4-10.

Slight risk of high winds for coastal parts of southcentral and southeastern
Alaska, Sun-Sat, Oct 4-10.

DETAILED SUMMARY

FOR TUESDAY SEPTEMBER 29 - SATURDAY OCTOBER 03:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR SUNDAY OCTOBER 04 - SATURDAY OCTOBER 10: The GEFS and ECENS are in good
agreement today on an amplifying 500-hPa ridge over interior western North
America during early October, which helps drive a cold front southward across
the Central and Eastern CONUS early in week-2.  Ahead of, and along the cold
front, there is a slight risk of heavy precipitation (3-day total of at least
one inch) for parts of the East and Gulf Coasts, Oct 4-6. The ECENS
precipitation PET favors a maximum of 30-40% chance for this hazard, while the
GEFS remains a bit more subdued with its probabilities. This is also supported
by 24-hour precipitation amounts from the GEFS and ECENS along with good model
continuity. The slight risk of heavy precipitation continues over the Florida
Peninsula at least into the latter portion of week-2, as the front stalls
across the area. This stationary front is expected to serve as a focus for
enhanced rainfall across the region. The Bay of Campeche will have to be
closely monitored for tropical cyclone (TC) development through early to
mid-October.



Following Hurricane Polo in the East Pacific, the National Hurricane Center
(NHC) states that there is a 90% chance of another tropical cyclone (TC)
forming offshore of southwestern Mexico within the next week. By week-2, there
is a large spread among the GEFS and ECENS ensemble members on the eventual
track of this likely TC. Therefore, uncertainty is high on how much if any
rainfall shifts north into the Desert Southwest from Oct 4-10.



In the wake of a strong cold front for early October, multi-model ensemble mean
solutions are in good agreement indicating a surface high shifting south from
Canada into the northcentral CONUS. A slight risk of much below normal
temperatures, valid Oct 4-7, is posted for the Great Lakes region and interior
Northeast where the ECENS Probabilistic Extremes Tool (PET) depicts >20% chance
of minimum temperatures falling below freezing and the 15th percentile
climatologically. This would be the first widespread frost and freeze of the
season for these areas. Typically, the first 32 deg F freeze of the fall occurs
either in late September (western Great Lakes and Maine) or early October (for
most of the remaining temperature hazard region shown on map).



A highly amplified 500-hPa trough over the northeast Pacific is likely to
promote a series of low pressure systems that track from the Alaska Peninsula
eastward to the Gulf of Alaska. Based on the enhanced onshore flow associated
with these low pressure systems, and support from the ECENS and GEFS PETs (20%
chance of 3-day precipitation amounts > 85th percentile and 2-3 inches), a
slight risk of heavy precipitation is designated from the Kenai Peninsula to
southeastern Alaska. Since the GEFS, ECENS, and CMCE persist the deep 500-hPa
trough over the North Pacific through early October, the heavy precipitation
hazard is maintained for the entirety of week-2. Although most of the model
ensemble members only depict surface lows of moderate strength, a slight risk
of high winds is maintained based on pattern recognition and support from the
ECENS PET wind tool. The high wind hazard is also valid from Oct 4-10.



An area of low pressure about 1000 miles east-southeast of the Hawaiian Islands
has a 70 percent (high) chance of tropical development within the next week,
according to the National Hurricane Center. Although environmental conditions
appear to be conducive for development of a tropical depression, the system is
predicted to move northeastward away from Hawaii. This is good news for the
residents of Hawaii that have already experienced a memorable hurricane season
this year.

FORECASTER: Anthony Artusa

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