786 
FXUS02 KWBC 291855
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
255 PM EDT Wed Oct 29 2025

Valid 12Z Sat Nov 01 2025 - 12Z Wed Nov 05 2025


...Overview...

Guidance continues to advertise an amplified upcoming medium range
pattern aloft, at least through this weekend, which features mean 
troughing over the eastern U.S. and a building ridge out west. A 
potent shortwave drops southward from the Upper Midwest on 
Saturday to bring renewed amplified troughing over the East with 
still varied recent guidance overall still continuing to trend 
toward more stream separation with a possible cutoff closed low 
over or near the Gulf Coast region/vicinity by early next week. 
The tail end of an atmospheric river will keep the Northwest still 
wet into Saturday, but drier into early next week with upper 
ridging. Another deep trough will approach the West Coast by around
Wednesday of next week.

...Guidance/Predictability Assessment...

A main forecast concern continues to be with the shortwave trough 
dropping southward to the Midwest into Saturday, with possible 
cutoff closed low development over the Mississippi Valley to Gulf 
Coast by Sunday or Monday. Latest guidance trends continue to be 
for this scenario. Recent CMC runs advertised a more progressive 
amplified trough through the region, but the latest 12 UTC run has 
at least trended more amplified/less progressive. There is also 
uncertainty in whether any sort of closed low will linger near the 
Gulf Coast or lift off the Southeast coast. A few GFS and ECMWF 
runs have recently offered this latter possibility, but it is not 
shown in either's new 12 UTC run that are more in line with the 
GEFS/ECMWF ensemble means. The AIFS is more progressive than that 
solution now, but the AIFS ensemble mean is slower. Accordingly 
with uncertainty, the WPC forecast is close to the GEFS/ECMWF 
ensemble means that show stream separation and fairly slow 
progression that seems a good match to the larger scale flow. Out 
West, there is question on the timing of the next trough towards 
the coast late period and an ensemble mean blend seemed a good 
starting point with a gradual slower trend recently that seems 
consistent with amplifying flow.

...Weather/Hazards Highlights...

A departing strong surface low out of the Northeast/Canadian 
Maritimes will induce lake effect rains behind it. The shortwave 
dropping through the Midwest may bring some uncertain light rain 
showers with it, but additional rainfall may develop along the Gulf
Coast with weak surface low development along a trailing frontal 
boundary in the Gulf. Rain coverage may expand for the Southeast 
and East Coast early next week, but with much uncertainty and 
highly dependent on the pattern evolution into this region.

Locally moderate to heavy precipitation may linger into Saturday 
on the back end of a moderately strong atmospheric river into the 
Northwest late this week. But by Saturday, instability should be 
less and the better moisture anomalies will be quickly shifting 
eastward, so no marginal risk is planned at this time on the ERO 
since Friday should be the bigger day. Most precipitation is 
forecast to stay rain other than snow in the highest peaks of the 
Olympics and the Cascades. The region should trend drier Sunday 
with possibly another increase in precipitation early-mid next 
week again. Elsewhere, the Southwest to the Plains should stay 
mostly dry through the period under the warming ridge aloft. 

Much of the West can expect warmer than average temperatures 
underneath upper ridging through the period, expanding into the 
Central U.S. Sunday onward. Meanwhile, the East will be near to
just below normal temperatures underneath mean upper troughing.


Santorelli/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 (QPF), excessive rainfall 
outlook (ERO), winter weather outlook (WWO) probabilities, heat 
indices, and Key Messages can be accessed from:

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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