243
FXUS02 KWBC 131855
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
255 PM 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
A DEEP TROUGH WILL MOVE THROUGH THE GREAT LAKES/OHIO VALLEY AND
THE NORTHEAST FRIDAY AND SATURDAY. A STRONG COLD FRONT AND CHILLY
SURFACE HIGH PRESSURE BEHIND IT WILL BRING FROST AND 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. THE
NEXT TROUGH MOVES INTO THE WEST BY MONDAY BRINGING PERIODS OF RAIN
AND HIGH ELEVATION SNOW ACROSS MUCH OF THE WEST THROUGH MIDWEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODEL GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT WITH
THE LARGE SCALE PATTERN THROUGH MUCH OF THE MEDIUM RANGE PERIOD,
WITH ONLY LINGERING MINOR UNCERTAINTIES 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, WITH A COLD FRONT AND STRONG SURFACE HIGH
PRESSURE FOLLOWING IN ITS WAKE. MEANWHILE, MODELS CONTINUE TO
ADVERTISE A LARGE TROUGH DEVELOPING ALONG THE WEST COAST EARLY NEXT
WEEK. WHILE INDIVIDUAL SOLUTIONS SHOW DIFFERENCES IN TIMING AND
EVOLUTION, CONSENSUS FAVORS A STRENGTHENING SYSTEM WITH GREATER
IMPLICATIONS TO QPF, TEMPERATURES, AND PRECIPITATION TYPE.
THE UPDATED WPC FORECAST USED A BLEND OF THE DETERMINISTIC
GUIDANCE THROUGH DAY 5, INCREASING THE WEIGHTING OF ENSEMBLE MEAN
INCLUSION TO 40 PERCENT OF THE BLEND FOR DAYS 6 AND 7 AMIDST SOME
LINGERING 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 AND SATURDAY, ALONG WITH UPSLOPE
PRECIPITATION IN THE APPALACHIANS. GUSTY WINDS ARE LIKELY 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 RAINFALL
AMOUNTS POTENTIALLY INCREASING BY THE WEEKEND GIVEN PERSISTENT
ONSHORE FLOW IN THE WAKE OF THE FRONT. MUCH OF THE WEST SHOULD ALSO
SEE INCREASING PRECIPITATION CHANCES LATE WEEKEND INTO NEXT WEEK
AS ANOTHER DEEPENING TROUGH FORGES INLAND. FAIRLY WIDESPREAD
PRECIPITATION CONSISTING OF LOW ELEVATION RAIN AND HIGH ELEVATION
SNOW ARE BECOMING INCREASINGLY LIKELY. WITH THAT BEING SAID, AN
OVERALL DRIER PATTERN IS IN STORE BY THE WEEKEND INTO EARLY NEXT
WEEK FOR MUCH OF THE REMAINDER OF THE COUNTRY WITH HIGH PRESSURE
TAKING CONTROL.
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, ABOVE NORMAL TEMPERATURES
WILL RETURN FOR MUCH OF THE WEST BY LATE WEEK, INCLUDING SOME HIGHS
NEAR AND ABOVE 90 FOR PARTS OF COASTAL CALIFORNIA. ABOVE AVERAGE
TEMPERATURES ARE LIKELY TO SPREAD INTO THE NORTH-CENTRAL U.S. OVER
THE WEEKEND WITH THE WESTERN U.S. TROUGH COOLING TEMPS ALONG THE
COAST MONDAY INTO TUESDAY.
MILLER/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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