505
FXUS02 KWNH 050607
PREEPD

Preliminary Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
106 AM EST Thu Nov 5 2026

Valid 12Z Sun Nov 08 2026 - 12Z Thu Nov 12 2026


...Overview...

Persistent troughing over northeastern Pacific will support
multiple opportunities for precipitation and gusty winds across
the Pacific Northwest and West Coast. A potentially significant
moisture plume may approach the West Coast early next week,
bringing chances for coastal and low elevation rain and mountain
snow further inland. Farther east, periodic shortwave disturbances
rotating through the mean trough will support additional
opportunities for showers across the Great Lakes and Northeast.
Across the southern tier, a southern-stream trough is expected to
bring chances for showers and thunderstorms across the southern
Plains/Texas and Gulf Coast/Southeast through early next week.


...Guidance/Predictability Assessment...

Most of the latest model guidance exhibit reasonably good
agreement regarding deep troughing over the northeastern Pacific,
with downstream ridging across much of western and central U.S.,
and troughing across eastern U.S. for the first portion of the
period. The GFS seems to remain a outlier regarding the amplitude
and timing with shortwave features, particularly across the
southern tier. These differences will influence the placement and
magnitude for precipitation. Another forecast uncertainty remains
with the Pacific moisture plume approaching the West Coast next
week. Some models place the greatest moisture plume farther north
into British Columbia, while other solutions direct the moisture
towards western Washington. Therefore, the forecast favored a
multi-model blend of ECMWF/CMC and machine learning guidance
towards the first portion of the period, while blending in the
ensemble means towards the latter portion.



...Weather/Hazards Highlights...

The Pacific Northwest is expected to remain under the influence of
persistent troughing and periodic shortwave troughs approaching
from the northeastern Pacific. Several rounds of rain along the
coastal ranges and lower elevations, as well as coastal gusty
winds are possible as successive frontal systems move inland.
Locally heavier rainfall will be possible along favored coastal
terrain and windward slopes of the Cascades and northern portions
of the Intermountain West. Additionally, there is potential for a
more organized atmospheric river event approaching the West Coast
by early next week. This will support southwesterly flow and
enhance moisture transport into the Pacific Northwest and
potentially expand showers into California, with the potential for
mountain snowfall.

Meanwhile, a southern-stream trough is expected to progress
eastward across the southern tier and interact with Gulf and
Atlantic moisture. This will bring chances for showers and
thunderstorms across parts of Texas into the Gulf Coast/Southeast
through early next week. Increasing moisture return from the Gulf
ahead of the system and increasing instability will bring possible
localized flash flooding. WPC Excessive Rainfall Outlook (ERO)
continues the Marginal Risk for Sunday across portions of southern
Texas.

Across the Northeast and Great Lakes, lingering cyclonic flow
behind the frontal system will maintain periods of scattered
showers. Additional shortwave energy dropping southeastward from
Canada may reinforce the upper trough, while cold-air advection
support continued lake-effect showers downwind of the Great Lakes
through early next week.



Oudit


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, excessive rainfall outlook,
winter weather outlook probabilities, heat indices and Key Messages
are at:

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





































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