413
FXUS21 KWNC 011800
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT November 01 2025

SYNOPSIS: Mid-level low pressure forecast over the northeastern Pacific favors
an increased risk of heavy precipitation, high elevation snowfall, and high
winds over portions of the northwestern contiguous U.S. (CONUS) and
southeastern Alaska during week-2. Additional shortwave energy is predicted to
traverse the Northern Tier of the CONUS during the period favoring enhanced
chances for high winds and heavy precipitation over the Northeast and high
winds in the Great Plains. Increasing model spread reduces forecast confidence
during the second half of week-2.

HAZARDS

Slight risk of heavy precipitation across portions of the Pacific Northwest and
northern California, Sun-Wed, Nov 9-12.

Slight risk of heavy precipitation across New England, Sun, Nov 9.

Slight risk of heavy snow across portions of the Cascades, Sun-Wed, Nov 9-12.

Slight risk of heavy snow across portions of the Northern Rockies, Sun-Wed, Nov
9-12.

Slight risk of high winds across portions of the Pacific Northwest and northern
California, Sun-Wed, Nov 9-12.

Slight risk of high winds across portions of the Great Lakes, Appalachians,
Mid-Atlantic, and Northeast, Sun-Mon, Nov 9-10.

Slight risk of high winds across portions of the Plains and the Upper and
Middle Mississippi Valley, Sun-Tue, Nov 9-11.



DETAILED SUMMARY

FOR TUESDAY NOVEMBER 04 - SATURDAY NOVEMBER 08:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR SUNDAY NOVEMBER 09 - SATURDAY NOVEMBER 15: The 0z GEFS, ECENS, and CMCE
models remain in fair agreement regarding troughing across the northeastern
Pacific persisting into week-2. The models have differences in the timing and
intensity of various shortwave troughs and ridges along the West Coast. This
increases the uncertainty of the strength and timing of any enhanced onshore
flow. Nevertheless, tools are consistent for periods of enhanced precipitation
and coastal high winds through the first half of week-2. Both the GEFS and
ECENS Probabilistic Extremes Tools (PETs) indicate at a 20-30 percent chance
3-day precipitation totals exceed the 85th climatological percentile and 1.5
inches early in week-2, with chances decreasing later in the period. The ECENS
Integrated Vapor Transport (IVT) tool continues to indicate enhanced
probabilities of IVT values exceeding 250 kg/m/s through about day-11 (Nov 12),
while the GEFS IVT has a weaker signal early in the period before a resurgence
towards the middle of week-2. This is consistent with the ECENS, and also the
CMCE, showing a stronger ridge across the interior West persisting through the
middle of the period with a more progressive GEFS with a shortwave trough axis
over the interior West early in week-2. Based on the above guidance, there is
enough support to maintain the slight risk for heavy precipitation across the
Pacific Northwest and northern California through Nov 12. Any heavy
precipitation is likely to lead to increased streamflows and possibly isolated
urban flooding within the highlighted precipitation area.



A slight risk for high winds is also posted over coastal areas of the Pacific
Northwest and northwestern California, where the GEFS and ECENS PETs depict at
least a 20 percent chance wind speeds exceed 25-mph, along with an enhanced
signal for wind speeds exceeding 40-mph just offshore. Lastly, slight risks for
heavy snow are posted across the Cascades and Northern Rockies. Signals in the
models are marginal, but 24-hour amounts exceeding 4-inches are possible, with
higher totals favored over the northern Cascades. The aforementioned wind and
snow hazards are valid through Nov 12.



There is more uncertainty further east. The timing and placement of multiple
shortwave troughs over the central and eastern CONUS is different between the
GEFS, ECENS, and CMCE and difficult to place. Initially, an area of low
pressure is forecast to be over or near the Northeast. The ECENS is a bit
slower with this feature maintaining high winds and a heavy precipitation
chances over the Great Lakes and Northeast until day 8. Meanwhile, most of the
GEFS signal has already moved offshore by the start of week-2. In deference to
continuity, have maintained a slight risk of heavy precipitation over New
England for Nov 9. A broader slight risk of high winds is forecast for the
Great Lakes and Northeast for Nov 9-10 as winds may remain elevated following a
frontal passage.



Meanwhile, the GEFS favors bringing another shortwave trough into the Rockies
and spinning up an area of low pressure in the lee of the Rockies. The GEFS PET
and raw ensemble guidance support a relatively broad slight risk of high winds
across much of the Plains. The ECENS and the ECENS AI raw guidance is not as on
board with this solution as the mean ensemble guidance does not support a
shortwave trough early in the period. However, there is some support from the
ECENS PET for wind speeds exceeding the 85th percentile. Therefore, a slight
risk of high winds is posted for Nov 9-11.



Across Alaska, periods of high winds and locally heavy precipitation are
possible over the Southeast associated with anomalous mid-level troughing over
the northeastern Pacific and Bering Sea. However PETs show precipitation
amounts and wind speeds likely remaining below hazard thresholds.

FORECASTER: Ryan Bolt

$$