513
FXUS02 KWBC 010758
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
358 AM EDT Thu Oct 1 2026

Valid 12Z Sun Oct 04 2026 - 12Z Thu Oct 08 2026


...Lingering Gulf Coast/Southeast U.S. Excessive Rainfall/Flooding
threat Sunday into Monday...


...Guidance/Predictability Assessment...

Guidance forecast spread is above average through medium-range
time scales, bolstering confidence. A favored composite of overall
compatible model, ensemble mean and machine learning guidance
seems to offer a solid forecast base for consistent threat
messaging and products mainly in line with the National Blend of
Models. Greater uncertainty remains with smaller scale convective
interaction and local focus. The composite will tend to mitigate
variance as consistent with individual feature predictability.

...Pattern Overview and Weather/Hazards Highlights...

A main southern stream upper trough and wavy/wet frontal system
will shift slowly eastward from the South-central U.S. this
weekend. Leading excessive rainfall/flooding threats will work
slowly across the South/Southeast as fueled by deepened Gulf
inflow. A WPC Excessive Rainfall Outlook Marginal Risk area from
coastal Texas through the Gulf Coast states and the Southeast for
Day4/Sunday also has an embedded Central Gulf Coast Slight Risk
area is in place lingering onshore into Monday. Meanwhile, systems
within a more progressive northern stream flow will support passage
of a series of wavy frontal systems down from the U.S. northern
tier. These fronts with stream phasing over time with northern
stream amplification will broadly deliver fall temperatures and a
drier airmass southward along with high pressure onset. This will
further act to shift southward and confine the lead focus for heavy
rainfall/flooding threats with slow/wavy frontal sag through the
Gulf Coast/Southeast and more offshore into the Gulf next week.

Elsewhere, upper-ridging will lead to a period of above-average
temperatures over the western U.S. including highs into the 90s and
low 100s for central/southern California and the Desert Southwest.
The heat will reach hazardous levels in southern California into
the weekend and at least through early next week.

Schichtel


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast, excessive rainfall outlook,
winter weather outlook probabilities, heat indices and Key Messages
are at:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw


































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