373
FXUS02 KWNH 110759
PREEPD

Preliminary Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EST Tue Nov 11 2025

Valid 12Z Fri Nov 14 2025 - 12Z Tue Nov 18 2025


...Overview...

A southern stream upper low will be traversing the Southwest and
northern Mexico late this week into the weekend, bringing
widespread precipitation to those areas. Rain and possible
thunderstorms are forecast to move into the south-central U.S. by
around Sunday and possibly the east-central U.S. into Monday as
this feature lifts. Upper ridging ahead of this system will lead to
much warmer than average temperatures across the central and then
eastern U.S. into the weekend. Meanwhile in the northern stream, an
upper trough will direct a surface low/frontal system across the
Great Lakes and Northeast over the weekend, leading to rain and
snow. Yet another trough moving across the northeastern Pacific
into the West should bring precipitation chances to the Pacific
Northwest and farther east into the Intermountain West early next
week.


...Guidance/Predictability Assessment...

Model agreement is much better than it has been in recent days on
the complex overall pattern described above, but models still show
differences that could be impactful to sensible weather. Models
have converged on a solution favoring a southern stream upper low
in the Southwest that should be closed and cut off from the
northern stream. Not much recent guidance indicates a phased trough
anymore, though there are a handful of ensemble members that still
do. Within the broader agreement for a southern stream closed low,
there are still some timing differences. Most AI based guidance
(with the exception of the FourCastNet initialized by both the EC
and GFS) have a slower track of the closed low compared to the
dynamical models. So as a nod to the AI models, generally preferred
the slower deterministic models for forecast creation today,
favoring the 12Z ECMWF, 18Z GFS, 12Z CMC, and 18Z GEFS into the
weekend period. The 12Z UKMET was a little faster and thus not
preferred, as was the 12Z EC ensemble mean with members still
eastward. The new 00Z models have generally slowed just a tad but
are mostly similar to the previous cycle as the upper low starts to
weaken and lift through the south-central Plains and northeastward
early next week.

In the northern stream, 12/18Z guidance showed some differences in
the timing of the Great Lakes to Northeast trough, impacting its
surface low positions (and QPF) Sunday-Monday. The 18Z GFS seemed
particularly fast/farther east with the trough. Fortunately the
incoming 00Z model suite seems to be converging on better
agreement. South of this trough and east of the southern stream
low, upper ridging is agreeable.

Then for the West, troughing moving east over the northeast
Pacific over the weekend shows good consistency, but there is some
spread on whether this trough will split into northern and southern
stream components into early next week. The 18Z GFS showed the
possibility of an upper low pinching off in the southern stream
near California, and the 00Z GFS and now the 00Z CMC are indicating
this type of pattern as well. Will continue to monitor as the
trough structure would affect sensible weather like precipitation
in the West.

As stated, the early part of the medium range period was based on
a blend of the 18Z GFS/GEFS and 12Z ECMWF/CMC. Increased the
proportion of ensemble means as the period progressed, reaching
over half Day 7.


...Weather/Hazards Highlights...

The tail end of an atmospheric river may impact southern
California Friday, while the upper low developing provides
dynamical support for ample precipitation, mostly rain, across the
Southwest. Moisture (precipitable water) will likely be over the
95th percentile for this time of year, and some modest instability
exists ahead of and underneath the deep upper low. Precipitation
should initially be mostly rain even into parts of the Mogollon Rim
until the upper low passes over. Marginal Risks of excessive
rainfall have been delineated for parts of southern California into
Arizona on Day 4/Friday into Day 5/Saturday for isolated flooding
concerns with this system. Rain is likely to spread east into the
Southern and Central Plains into the Lower and Middle Mississippi
Valley by Sunday. Thunderstorms are also a good possibility given
instability and Gulf moisture ahead of the upper low. There is more
model spread by Monday, but rain generally could continue shifting
east into the Ohio Valley stretching to the central Gulf Coast.

Some lake effect precipitation could continue across the Northeast
on Friday, but broader precipitation chances are likely to come
into the northeastern quadrant of the CONUS over the weekend as a
low pressure system moves through. Some snow is likely in the
Interior Northeast, especially in higher elevations.

Periodic precipitation is likely across the Pacific Northwest and
Intermountain West into late week, with higher elevation snow. By
Sunday, precipitation chances should ramp up into northern
California and farther inland as well, as broad upper troughing
approaches. Troughing looks to move through the West early next
week and could spread precipitation across the Intermountain West
once again, though the details remain uncertain.

Temperatures are forecast to be warmer than average for mid-
November across the central U.S. on Friday. The Northern Plains
should see the most anomalous temperatures, as highs soar into the
60s and 70s, around 20-25 degrees above normal. 80s will be
widespread across Texas with 70s in the rest of the Plains and into
the Mid/Lower Mississippi Valley and Southeast. Temperatures
should cool in the north-central U.S. over the weekend, but remain
warm farther south and spreading eastward (though with lesser
anomalies). By the workweek the upper low/trough will generally
cool temperatures, though the Gulf Coast states could stay a few
degrees above average. 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


$$