553
FXUS02 KWBC 140718
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
318 AM EDT WED OCT 14 2026
VALID 12Z SAT OCT 17 2026 - 12Z WED OCT 21 2026
...BROAD FROST/FREEZE THREATS ACROSS THE NORTH-CENTRAL INTO THE
EAST THIS WEEKEND AND INTO EARLY NEXT WEEK...
..OVERVIEW
A DEEP TROUGH WILL MOVE THROUGH THE EAST ON SATURDAY WITH A STRONG
COLD FRONT AND CHILLY SURFACE HIGH PRESSURE BEHIND IT TO 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 ASSOCIATED WITH THIS SYSTEM ARE POSSIBLE BEHIND THE
DEEP LOW INTO SATURDAY FOR THE NORTHEAST. 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 TROUGH WILL PUSH A STRONG
SURFACE LOW THROUGH THE NORTHEAST BY SATURDAY, WITH A COLD FRONT
AND STRONG SURFACE HIGH PRESSURE FOLLOWING IN ITS WAKE. MINOR
TIMING AND AMPLITUDE DIFFERENCES REMAIN WITH THIS FEATURE.
MEANWHILE, MODELS CONTINUE TO ADVERTISE A LARGE AND DEEPENING
TROUGH MOVING INTO THE WEST EARLY TO MID NEXT WEEK. CONSIDERABLE
UNCERTAINTY REMAINS WITH THIS SYSTEM REGARDING SEPARATION AND
PLACEMENT OF AN UPPER LOW OVER OR NEAR THE SOUTHWEST NEXT WEDNESDAY
WITH PLENTY OF RUN TO RUN VARIABILITY IN THE LATEST GUIDANCE.
THE UPDATED WPC FORECAST USED A BLEND OF THE DETERMINISTIC
GUIDANCE THROUGH DAY 5, INCREASING THE WEIGHTING OF ENSEMBLE MEAN
INCLUSION TO 50 PERCENT OF THE BLEND FOR DAYS 6 AND 7 AMIDST
GREATER UNCERTAINTY OUT WEST. DESPITE THE GROWING UNCERTAINTY AND
LIKELIHOOD FOR ADDITIONAL CHANGES IN THE WEST, THIS GENERALLY
MAINTAINS GOOD CONTINUITY WITH THE PREVIOUS WPC FORECAST FOR NOW
AND WAS CONSISTENT WITH THE 01Z NATIONAL BLEND OF MODELS.
..WEATHER/HAZARDS HIGHLIGHTS
THE DEEP SURFACE LOW ASSOCIATED WITH THE EAST COAST TROUGH WILL BE
OFF INTO THE CANADIAN MARITIMES BY SATURDAY, BUT MAY CONTINUE TO
BRING GUSTY WINDS, ESPECIALLY FOR HIGHER ELEVATIONS, AS WELL AS
SOME LIGHT LAKE ENHANCED RAIN AND SNOW DOWNWIND OF THE LOWER GREAT
LAKES AND UPSLOPE IN THE CENTRAL AND NORTHERN APPALACHIANS. AS THE
COLD FRONT SWINGS THROUGH FLORIDA, SHOWERS AND STORMS ARE POSSIBLE,
WITH LOCALLY HEAVY TO EXCESSIVE RAINFALL POSSIBLE. MUCH OF THE
WEST SHOULD ALSO SEE INCREASING PRECIPITATION CHANCES LATE WEEKEND
INTO NEXT WEEK AS ANOTHER DEEPENING TROUGH MOVES 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.
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 IN
THE WEST WILL SPREAD INTO THE NORTH-CENTRAL U.S. OVER THE WEEKEND
AND THE CENTRAL U.S. NEXT WEEK. DEEP TROUGHING WILL BRING MUCH
BELOW NORMAL TEMPS FOR MUCH OF THE WEST EARLY TO MID NEXT WEEK.
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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