308
FXUS21 KWNC 102011
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EST November 10 2025

SYNOPSIS: Dynamical models continue to favor an active pattern heading into
next week. Potentially strong mid-level low pressure is expected to bring an
increased risk of heavy precipitation, high elevation snow, and periods of high
winds across many parts of the Interior West. Surface low formation in the lee
of Rockies with ample moisture from the Gulf supports elevated chances for
heavy precipitation over the southcentral and southeastern contiguous U.S.
early in week-2. Mid-level low pressure centered over the Bering Strait and
associated surface low development may lead to locally heavy precipitation and
high winds over parts of the Alaska Mainland and the Southeast.

HAZARDS

Moderate risk of heavy precipitation for parts of the Southern Plains, Lower
Mississippi and Tennessee Valleys, and the Southeast, Wed-Thu, Nov 19-20.

Slight risk of heavy precipitation for much of the Great Plains, Mississippi,
Tennessee and Ohio Valleys, and Southeast, Tue-Sat, Nov 18-22.

Slight risk of heavy precipitation for much of the Southwest and southern
Rockies, Tue-Wed, Nov 18-19.

Slight risk of heavy snow over much of the Rockies and Great Basin, Tue-Thu,
Nov 18-20.

Slight risk of high winds for many parts of the western and central CONUS,
Tue-Thu, Nov 18-20.

Slight risk of high winds for parts of the Aleutians, Mainland, and Southeast
Alaska, Tue-Sat, Nov 18-22.

DETAILED SUMMARY

FOR THURSDAY NOVEMBER 13 - MONDAY NOVEMBER 17:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR TUESDAY NOVEMBER 18 - MONDAY NOVEMBER 24: Heading into early next week,
dynamical models remain in decent agreement, featuring an amplified mid-level
trough shifting eastward across the Interior West, with additional troughing
lifting out over the northeastern CONUS underneath a highly amplified 500-hPa
blocking ridge established near Greenland. As the period progresses, the 0z
GEFS and 0z ECMWF diverge in regards to the evolution of the mid-level pattern,
with the former model favoring a fairly muted pattern with weakly anomalous
mean troughing overspreading parts of the CONUS. In contrast, the ECMWF
ensemble shows much of the troughing remaining more amplified throughout the
West, including a full latitude of expansion of the mean negative height
departures to promote cooler temperatures along with the potential for renewed
onshore flow across western North America. Additionally, the ECMWF favors more
ridging to develop over the eastern half of the CONUS, where a classic
trough/ridge mean pattern looks to keep the threat of additional surface low
development in the lee of the Rockies and bring above normal, and possibly
heavy precipitation amounts over the Great Plains and Mississippi Valley during
the period.



Tied to the amplified troughing favored over the Interior West by the outset of
week-2, a slight risk of heavy snow remains posted over the higher elevations
of the Rockies, along with a slight risk of heavy precipitation over the lower
Four Corners region. Relative to yesterday, the snow hazard is expanded
southward to include Mogollon Rim of the Southwest and parts of the Southern
Rockies due to better support in the snow tools. A broad slight risk of high
winds also remains issued, with its coverage more oriented over the
south-central CONUS near the base and ahead of the amplified trough. Moderate
risks of heavy snow and high winds were considered for inclusion in the updated
outlook, however forecast confidence is tempered by the weaker mean troughing
solutions now being favored, as well as corresponding tools in the GEFS and
Canadian ensembles. However, models are in good agreement featuring surface low
development over the Southern Plains with ample return flow from the Gulf to
promote locally heavy precipitation amounts across the ArkLaTex region early in
the period. While the GEFS remains comparatively weaker with heavy
precipitation potential, both Probabilistic Extremes Tools (PETs) and raw tools
support the addition of a moderate risk of heavy precipitation over portions of
the Southern Plains, Lower Mississippi and Tennessee Valleys, and the
Southeast, valid for Nov 19-20. Within the highlighted area, raw tools indicate
40-60% chances for 3-day amounts exceeding an inch. A broader slight risk area
of heavy precipitation is posted and valid through Nov 22 where PETs maintain
at least 20% chances for 3-day amounts exceeding the 85th percentile. On the
backside of the mean surface low, it is worth noting that accumulating snowfall
is possible over the lower elevations of the Southern and Central High Plains.



With much of the anomalous troughing shifting eastward across the Interior
West, many areas of the West Coast look to take a break, at least temporarily,
from the enhanced onshore flow regime with lesser precipitation amounts in the
raw tools. This is reflected in the Integrated Vapor Transport (IVT) tools
early in week-2, which show little to no signal for values exceeding 250 kg/m/s
in both the GEFS and ECMWF ensembles following an increased risk of Atmospheric
River (AR) activity during week-1. The ECMWF IVT does show the return of
renewed AR signals by days 10 and 11 (Nov 20-21), however this is completely
absent in the GEFS likely due to more zonal flow being favored by the middle of
period. Therefore, no corresponding precipitation, snow or wind hazards are
posted, but this potential will continue to be monitored in upcoming outlooks.



Over Alaska, an amplifying 500-hPa trough centered over the Bering Strait is
expected to lead to one or more surface lows developing and potentially track
eastward into the Gulf of Alaska. Since yesterday, both the GEFS and ECMWF have
become stronger with these mean features, which are depicted in the PETs with
elevated wind and precipitation signals. While there is still some uncertainty
as to whether realized amounts exceed hazard thresholds, the mid-level and
surface pattern favored supports the addition of a slight risk of high winds.
Coverage extends from the Aleutians to the Southeast to capture the progression
of any surface low that develops.

FORECASTER: Nick Novella

$$