934
FXUS02 KWBC 130552
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
152 AM EDT TUE OCT 13 2026
VALID 12Z FRI OCT 16 2026 - 12Z TUE OCT 20 2026
...BROAD FROST/FREEZE THREATS ACROSS THE NORTHERN/CENTRAL U.S.
LATE WEEK INTO EARLY NEXT WEEK...
..OVERVIEW
THE PERIOD BEGINS FRIDAY WITH A DEEP TROUGH MOVING THROUGH THE
GREAT LAKES/OHIO VALLEY AND INTO THE NORTHEAST FRIDAY AND SATURDAY.
A STRONG COLD FRONT AND CHILLY SURFACE HIGH PRESSURE BEHIND IT
WILL BRING FROST/FREEZE CONCERNS TO A BROAD AREA ADVANCING FROM THE
PLAINS INTO THE MIDWEST AND THE EAST THIS WEEKEND AND EARLY NEXT
WEEK. GUSTY WINDS WILL ALSO ACCOMPANY THE SURFACE LOW AS IT MOVES
FROM THE GREAT LAKES INTO THE NORTHEAST FRIDAY AND SATURDAY.
MEANWHILE, AN UPPER LOW WILL MEANDER OVER THE SOUTHWEST THIS
WEEKEND BEFORE WEAKENING AND ITS ENERGY GETTING PULLED EASTWARD BY
ANOTHER WEAK SHORTWAVE THROUGH THE NORTHERN U.S.. THE NEXT TROUGH
MOVES INTO THE WEST BY MONDAY BRINGING PERIODS OF RAIN AND HIGH
ELEVATION SNOW ACROSS MUCH OF THE NORTHWEST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT THROUGH MUCH OF
THE PERIOD, WITH SOME UNCERTAINTY IN THE TIMING AND DETAILS OF
INDIVIDUAL SYSTEMS. AN AMPLIFIED SHORTWAVE WILL PUSH A STRONG
SURFACE LOW AHEAD OF IT FROM THE GREAT LAKES ON FRIDAY TO ATLANTIC
CANADA BY SATURDAY. LATEST GUIDANCE SHOWS ONLY MINOR TIMING
DIFFERENCES NOW WITH THIS. THERE IS SOME UNCERTAINTY AS WELL WITH
THE WEAKENING UPPER LOW OVER THE SOUTHWEST AS ITS ENERGY GETS
PULLED THROUGH THE CENTRAL PLAINS AND MID-SOUTH BY A NORTHERN
STREAM SHORTWAVE EARLY NEXT WEEK, BUT THIS SHOULD NOT BE
ACCOMPANIED BY IMPACTFUL WEATHER. OUT WEST, GUIDANCE CONTINUES TO
SHOW SOME TIMING DIFFERENCES WITH THE TROUGH AS IT APPROACHES THE
COAST AND THEN ALSO THE DETAILS AS IT DEEPENS OVER THE WEST EARLY
NEXT WEEK.
THE WPC FORECAST TONIGHT USED A BLEND OF THE DETERMINISTIC
GUIDANCE DAYS 3-5, INCREASING THE ENSEMBLE MEAN INCLUSION TO 50
PERCENT OF THE BLEND DAYS 6 AND 7 AMIDST SOME LARGER UNCERTAINTY.
THIS GENERALLY MAINTAINED GOOD CONTINUITY WITH THE PREVIOUS WPC
FORECAST AND WAS CONSISTENT WITH THE NATIONAL BLEND OF MODELS.
..WEATHER/HAZARDS HIGHLIGHTS
RETURN FLOW AROUND A HIGH OVER THE GULF AND MOISTURE FROM WHAT IS
CURRENTLY HURRICANE SIMON MAY CONTINUE TO BRING SOME LOCALLY HEAVY
RAINFALL TO PARTS OF THE SOUTHERN HIGH PLAINS THROUGH FRIDAY, WITH
A WPC MARGINAL RISK IN PLACE. FARTHER NORTH, AREAS OF RAIN ARE
FORECAST INTO THE GREAT LAKES AND NORTHEAST WITH A SURFACE LOW
LATER THIS WEEK. THE PATTERN WILL BE FAVORABLE FOR LAKE
EFFECT/ENHANCED RAIN AND EVEN SNOW ACROSS THE GREAT LAKES REGION TO
INTERIOR NORTHEAST THROUGH FRIDAY- SATURDAY, ALONG WITH UPSLOPE
PRECIPITATION IN THE APPALACHIANS. HIGH WINDS ARE POSSIBLE BEHIND
THE SURFACE LOW/COLD FRONT TRACK ACROSS THE GREAT LAKES FRIDAY,
INTO THE HIGHER ELEVATIONS OF THE NORTHEAST SATURDAY, AND ALSO
BEHIND THE TAIL END OF THE FRONT IN THE SOUTHWEST TO SOUTHERN HIGH
PLAINS. SHOWERS AND STORMS ARE POSSIBLE IN FLORIDA, WITH AMOUNTS
POTENTIALLY INCREASING BY THE WEEKEND WITH THE FRONT PASSING
THROUGH. ELSEWHERE, THE PACIFIC NORTHWEST INTO THE NORTHERN
INTERMOUNTAIN WEST AND ROCKIES SHOULD SEE INCREASING PRECIPITATION
CHANCES INTO SUNDAY AND MONDAY AHEAD OF THE NEXT UPPER TROUGH. BUT
OVERALL A DRIER PATTERN IS IN STORE BY THE WEEKEND INTO EARLY NEXT
WEEK FOR MUCH OF THE REMAINDER OF THE COUNTRY.
ABOVE NORMAL TEMPERATURES ACROSS THE SOUTHEAST AT THE END OF THE
SHORT RANGE PERIOD MAY MODERATE AND LINGER INTO FRIDAY. THEN,
CANADIAN HIGH PRESSURE IS FORECAST TO GRADUALLY TRACK ACROSS THE
COUNTRY BEHIND THE COLD FRONT INTO THE WEEKEND, COOLING
TEMPERATURES FOR THE CENTRAL AND EASTERN U.S. AND PROVIDING FAIRLY
BROAD FROST/FREEZE THREATS. MEANWHILE, THE WEST COAST COULD SEE
ABOVE NORMAL TEMPERATURES, INCLUDING SOME HIGHS NEAR AND ABOVE 90
FOR PARTS OF COASTAL CALIFORNIA AGAIN BY LATE WEEK. ABOVE AVERAGE
TEMPERATURES ARE LIKELY TO SPREAD INTO THE NORTH-CENTRAL U.S. OVER
THE WEEKEND WITH THE WESTERN TROUGH COOLING TEMPS ALONG THE COAST
BY NEXT MONDAY.
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, 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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