834
FXUS02 KWNH 130753
PREEPD

Preliminary Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
252 AM EST Thu Nov 13 2025

Valid 12Z Sun Nov 16 2025 - 12Z Thu Nov 20 2025


...Overview...

Multiple rounds of troughing are forecast to move through the
western U.S. next week, bringing periodic rain and higher elevation
snow. A surface low moving through and exiting the Northeast
Sunday could bring some wintry precipitation behind it. Then a low
pressure/frontal system will spread some precipitation (mostly
rain) to the Mississippi and Ohio Valley Monday and stretching
across the south-central U.S. into the Appalachians Tuesday as the
front starts to stall. Increasing lift aloft could yield heavy
rainfall for the southern Plains/Lower Mississippi Valley into
midweek. Temperatures should be warmer than average for the central
U.S. Sunday, but become more limited to the southeastern quadrant
of the lower 48 during the workweek, to the south of the stalling
west-east oriented front.


...Guidance/Predictability Assessment...

Model guidance begins the period Sunday in good overall agreement
with the primary features, namely shallow but broad troughing
centered over the Great Lakes and a deepening Northeast surface
low, warm upper ridging over the High Plains, and a southern stream
closed low in the central Great Basin/Southwest. The southern
stream low exhibits some model spread as it lifts into the central
High Plains or vicinity Monday and opens into a shortwave, and
spread continues to increase as it moves eastward. GFS runs have
been quicker to track the upper low and its surface low reflection
eastward and weaken it compared to other dynamical and AI guidance.
ECMWF and CMC were more favorable with this system.

Upstream, troughing moving through the eastern Pacific into the
West early next week shows model spread in terms of timing and
potential for splitting northern and southern streams. The 12Z CMC
was most aggressive in showing a fast northern stream trough by
Monday and southern stream upper low development well west into the
eastern Pacific compared to other guidance. The 00Z CMC still
favors a low splitting into the southern stream, but not as far
west as the 12Z run. Recent GFS/ECMWF runs are generally at least
agreeable enough to blend with their ensemble means for a phased
trough (with some chance of an upper low to form within it). Yet
another trough could progress toward the Pacific Northwest by
Wednesday-Thursday.

The WPC forecast used a multi-model blend favoring the ECMWF early
in the forecast period. As the period progressed, eliminated the
GFS (not favored in the central/eastern U.S.) and CMC (not favored
in the western U.S.) in favor of the ensemble means. The means
comprised half the blend Day 6 and a bit more Day 7 amid increasing
spread.


...Weather/Hazards Highlights...

As the period begins Sunday, the initial southern stream closed
low will lift across the interior West. As it does so, it should
gradually lose the deeper moisture connection, but widespread
precipitation is likely across the West. Modest precipitation
(mostly rain even into parts of the Mogollon Rim) is forecast to
march across Arizona with the associated cold front, but the quick
movement and less significant moisture anomalies should keep
flooding potential lower than Marginal ERO levels. Farther north
into the Intermountain West, snow is likely in the higher
elevations, with some heavy amounts possible in the San Juans and
central Rockies. Another round of troughing should reach the West
Coast later Sunday into Monday and promote additional
precipitation. Any atmospheric river accompanying the frontal
system moving into the West should be much weaker than the system
during the short range period. However, plan to have a Marginal
Risk in the ERO for Day 5/Monday for the Transverse Ranges of
southern California, as this area tends to be sensitive due to
terrain enhancement of precipitation and burn scars, and heavy rain
is expected there just a day or two before. Continue to monitor
for changes to the forecast. Rain and higher elevation snow will
continue tracking east into Tuesday, and yet another possible upper
trough may bring additional precipitation to the West Coast by
Wednesday. Precipitation could be moderate or heavy at times.

Precipitation chances are likely across the Northeast Sunday into
Monday with and behind a relatively deep surface low pressure
system pulling away. Light precipitation is also forecast with
westerly flow over the Appalachians. Gusty winds are possible in
these areas as well.

A frontal system emerging into the central U.S. on Monday should
start to spread rain into the north-central Plains, Middle
Mississippi Valley, and Ohio Valley, with perhaps some snow/mix on
the northern edge of the precipitation shield. The front is
currently forecast to stretch across the southern Plains to
Mississippi Valley and Ohio/Tennessee Valley on Tuesday, bringing
rain chances there and into the southern/central Appalachians and
Mid-Atlantic. Initial forecasts show that as another front
approaches the High Plains midweek along with troughing aloft,
deeper moisture may reach the stalling front and produce heavy
rainfall across the south-central U.S. along with potential
thunderstorms. Continue to monitor for changes to the forecasts as
the details remain uncertain.

Temperatures are forecast to be warmer than average for much of
the central to southern U.S. on Sunday. Highs in the 60s should
reach the central High Plains, around 10-15 degrees above average,
while highs in the 80s will be common across Texas, Louisiana, and
Florida with 70s across the rest of the Southeast. The southern
Plains to Southeast can expect temperatures to remain warmer than
average through much of next week to the south of the west-east
oriented front. There are some model differences in frontal
position that will be the dividing line between near normal to
above normal conditions, so the temperature forecasts will continue
to be refined. Meanwhile the rounds of troughing in California to
the Southwest will lead to below average highs there most days.


Tate


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


$$