423
FXUS21 KWNC 161923
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EST November 16 2025

SYNOPSIS: Strong mid-level high pressure over Alaska and deepening mid-level
low pressure over the western contiguous U.S. (CONUS) are predicted early in
the week-2 forecast period. Mid-level high pressure is also forecast across the
eastern CONUS. This mid-level pattern is expected to drive various hazards
across the Lower 48 states during week-2, including an inflow of Arctic air,
heavy mountain snow, and gusty winds for portions of the West. Over the Central
and especially Eastern CONUS, unseasonably warm temperatures are expected
during the first half of week-2, potentially followed by an Arctic air outbreak
across the north-central states during the second half of the period. With this
Arctic blast comes increased chances of heavy snow and gusty winds across
portions of the Plains, Upper Mississippi Valley, and Upper Great Lakes region,
while many areas to the south may be impacted by heavy precipitation and
flooding.

HAZARDS

Slight risk of heavy precipitation for eastern portions of the Southern Plains,
Middle and Lower Mississippi Valley, southern Ohio and Tennessee Valleys, and
adjacent parts of the Southeast, Mon-Fri, Nov 24-28.

Slight risk of heavy snow for much of the mountainous West, Mon-Sun, Nov 24-30.

Slight risk of heavy snow over much of the Plains, Upper Mississippi Valley,
and Upper Great Lakes region, Wed-Sun, Nov 26-30.

Slight risk of much below-normal temperatures across much of the western half
of the CONUS, Wed-Sun, Nov 26-30.

Slight risk of high winds over most of the CONUS, Mon-Sun, Nov 24-30.

Flooding possible in the general vicinity of the Arklatex.

DETAILED SUMMARY

FOR WEDNESDAY NOVEMBER 19 - SUNDAY NOVEMBER 23:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR MONDAY NOVEMBER 24 - SUNDAY NOVEMBER 30: Early in the week-2 period, a
strong mid-level ridge over Alaska is expected to contribute to the deepening
of a mid-level trough downstream over the western CONUS. This scenario is
predicted to bring anomalously warm air to Alaska and anomalously cold Arctic
air to the western Lower 48 states. Anomalously warm temperatures predicted in
southwestern Alaska favors precipitation in the form of rain rather than snow
for many areas, which could lead to a number of hazardous impacts including
coastal erosion, flooding, and a decrease in the stability of ice on rivers and
lakes. For the western CONUS, temperatures are expected to fall below +10 deg F
across much of the Interior, and a hard freeze (28 deg F) is a significant
concern for near-coastal areas of the Pacific Northwest, including Seattle and
Portland. These minimum temperatures could bring an end to the growing season
across Oregon`s Willamette Valley, and are supported by 0z runs of the ECENS
and GEFS. A hard freeze is also predicted for the remaining portions of New
Mexico and West Texas that have not yet experienced a killing frost. A slight
risk of much below-normal temperatures is therefore favored across much of the
western half of the CONUS, Nov 26-30.



As the mid-level trough deepens across the West and progresses slowly eastward,
a slight risk for heavy snow is posted for much of the mountainous West, Nov
24-30. This is consistent with raw (uncalibrated) snowfall guidance from the
ECENS and (to a lesser extent) the GEFS, with predicted snowfall totals in
excess of 6 inches, and locally a foot or more in the highest elevations. Broad
cyclonic curvature and cold air aloft is expected to maintain the necessary
instability to generate significant snowfall across the West, substantially
boosting mountain snow packs in the process. Today`s heavy snow hazard also
extends south of the Cascades into the Klamath/Siskiyou Ranges and
northern/central Sierras of California to about Lake Tahoe. In addition to the
predicted Arctic air and heavy snow hazards across the West, increased chances
for gusty winds of 20-30 mph or more are indicated by the ECENS and GEFS
Probabilistic Extremes Tools (PETs) wind guidance. This is further supported by
forecast 10-meter wind speeds from the 0z ECENS, and the expectation of tighter
surface pressure gradients. These tighter pressure gradients are expected to be
near the southern edges of advancing Arctic air masses surging southward across
the West. Accordingly, a slight risk of episodic high winds is favored across
most of the Western CONUS for the duration of week-2.



Over the Central and especially Eastern CONUS, unseasonably mild temperatures
are forecast during the first half of week-2. Multiple models depict the onset
of an Arctic outbreak towards the middle of the period across the north-central
CONUS. Daily uncalibrated ECENS/GEFS guidance predicts lee cyclogenesis over
the vicinity of eastern Colorado, with the developing cyclone then tracking
northeastward towards the Upper Great Lakes region. This is a very common storm
track for late November. A slight risk of heavy snow (>85th historical
percentile and 4-6+ inches) is posted for the northern and western flanks of
this cyclonic system, which may cause travel disruptions around the
Thanksgiving holiday. The area expected to be most affected by this storm
system includes the northern and central Great Plains, southern High Plains,
Upper Mississippi Valley, and the Upper Great Lakes region. Farther to the
southeast, an area of heavy precipitation is indicated over south-central and
southeastern portions of the CONUS as far north as the Ohio Valley, Nov 24-28.
This is attributed to expected low-level inflow of relatively mild, moist Gulf
air circulating around a surface high pressure center located off the Southeast
coast, interacting with a baroclinic zone. Precipitation amounts of at least
1-inch are forecast (3-day period), and 3-5 inches of precipitation are
predicted for much of this same area during the antecedent week-1 period. An
area of possible flooding continues to be posted across the vicinity of the
Arklatex.



For much of the CONUS east of the Rockies, dynamical models indicate several
low pressure systems are anticipated to move through these regions during the
week-2 period, accompanied by gusty northwesterly winds of 20-30 mph. Multiple
storm systems affecting the Central and Eastern CONUS at different times during
week-2 necessitates the designation of a very broad area of episodic high
winds. Climatological snow belt areas downwind of the Great Lakes may
experience a significant ramp-up in lake-effect snowfall, but most likely after
the end of this week-2 forecast period. By that time it is more likely for
Arctic air outbreaks to reach the East, and the Great Lakes should be mostly
free of ice.

FORECASTER: Anthony Artusa

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