044
FXUS02 KWBC 081958
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 PM EST MON DEC 8 2025
VALID 12Z THU DEC 11 2025 - 12Z MON DEC 15 2025
...POTENTIALLY HAZARDOUS COLD IS POSSIBLE FOR PORTIONS OF THE
NORTHERN PLAINS AND UPPER MIDWEST THIS WEEKEND...
..OVERVIEW
A BROAD UPPER LEVEL TROUGH WITH REINFORCING SHORTWAVES WILL
CONTINUE TO DOMINATE AREAS EAST OF THE ROCKIES WITH BROAD RIDGING
PERSISTING ALONG THE WEST COAST THROUGH THIS WEEKEND, THOUGH THE
AMPLITUDE OF BOTH MAY WEAKEN SOME BY NEXT WEEK. WHILE THE HEAVY
PRECIPITATION AND HIGH WIND THREAT FADES IN THE NORTHWEST,
GENERALLY PROGRESSIVE CLIPPER SYSTEMS WILL BE FAVORED IN THIS
PATTERN EAST OF THE ROCKIES WITH ENHANCED NORTHERN TIER WIND/SNOW
CHANCES AND LAKE EFFECT SNOW IN THE LEE OF THE GREAT LAKES. AN
ARCTIC AIRMASS WILL MOVE IN TO PORTIONS OF THE NORTH-CENTRAL U.S.
BRINGING MUCH BELOW NORMAL TEMPERATURES AND POTENTIALLY HAZARDOUS
COLD.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT ON THE OVERALL LARGE
SCALE PATTERN, BUT DIFFERENCES IN THE DETAILS WHICH IMPACTS
SENSIBLE WEATHER. FOR THE FIRST HALF OF THE PERIOD, A GENERAL
DETERMINISTIC MODEL BLEND WORKED WELL AS A STARTING POINT FOR THE
WPC SURFACE FRONTS/PRESSURES/500 HPA HEIGHTS. FOR SUNDAY INTO
MONDAY, THERE ARE SOME DIFFERENCES IN THE AMPLITUDE OF THE
REINFORCED EASTERN TROUGH AND WESTERN RIDGE, WITH THE GFS GENERALLY
MORE AMPLIFIED THAN THE ECMWF OR CMC. LEANED A BIT HEAVIER ON THE
ENSEMBLE MEANS LATE PERIOD TO ACCOUNT FOR THESE DIFFERENCES. FOR
SENSIBLE WEATHER GRIDS, THE 13Z NBM REMAINS A GOOD STARTING POINT,
BUT DID HAVE TO INCREASE COVERAGE OF PRECIPITATION ACROSS THE
NORTHERN PLAINS/UPPER MIDWEST AND INTO THE GREAT LAKES (AS WELL AS
THE SOUTH) FOR SOME PERIODS.
..WEATHER/HAZARDS HIGHLIGHTS
THE HEAVY PRECIPITATION AND WIND THREAT ACROSS THE NORTHWEST IS
MOSTLY IN THE SHORT RANGE PERIOD NOW, BUT PRECIPITATION SHOULD
CONTINUE INTO THURSDAY. A MARGINAL RISK REMAINS ON THE DAY
4/THURSDAY ERO TO ACCOUNT FOR SATURATED SOILS FROM PRIOR DAYS HEAVY
RAIN. SNOW IS POSSIBLE IN THE HIGHEST TERRAIN OF THE WASHINGTON
CASCADES.
A CLIPPER SYSTEM/DISTURBANCE INTO THE NORTHERN HIGH PLAINS WILL
INTERACT WITH A STATIONARY FRONTAL BOUNDARY AND THE NORTHERN
ROCKIES TO BRING HEAVY SNOW THREATS TO PORTIONS OF CENTRAL TO
EASTERN MONTANA THURSDAY- FRIDAY, WITH SEVERAL INCHES OF SNOW
POSSIBLE. ADDITIONAL ENERGY ROUNDING THE BASE OF THE TROUGH
CENTERED OVER THE EASTERN THIRD OF THE COUNTRY WILL BRING ROUNDS OF
GENERALLY LIGHT PRECIPITATION, MAINLY SNOW, INTO THE MIDWEST/GREAT
LAKES AND EASTWARD TOWARDS THE APPALACHIANS AND NORTHEAST THROUGH
THE WEEKEND. TO THE SOUTH, REINFORCING FRONTS SLOWING AS THEY
APPROACH FLORIDA WILL BRING DAILY RAIN THREATS NEAR THE GULF
COAST/FLORIDA AND POSSIBLY NORTHWARD INTO PARTS OF THE MID-SOUTH
ALONG FRONTAL BOUNDARIES.
A STRONG TEMPERATURE GRADIENT IS FORECAST ACROSS THE HIGH PLAINS
THURSDAY INTO EARLY NEXT WEEK WITH 15-25F ABOVE AVERAGE
TEMPERATURES ACROSS THE WEST AND 20-30F BELOW AVERAGE TEMPERATURES
FRIDAY THROUGH THIS WEEKEND FROM THE NORTHERN PLAINS ACROSS THE
GREAT LAKES, MIDWEST, AND OHIO VALLEY. THIS MAY RESULT IN HAZARDOUS
COLD AS MORNING TEMPERATURES DIP BELOW ZERO WITH WIND CHILLS NEAR
-20 DEGREES. THIS AIRMASS WILL MODERATE SOMEWHAT AS IT MOVES INTO
THE OHIO VALLEY AND EAST NEXT WEEK. MUCH OF THE SOUTH, GULF COAST,
AND FLORIDA WILL BE NEAR NORMAL THROUGH THE PERIOD.
SANTORELLI
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
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