495
FXUS02 KWBC 040711
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
211 AM EST TUE NOV 4 2025
VALID 12Z FRI NOV 07 2025 - 12Z TUE NOV 11 2025
..OVERVIEW
THE UPPER LEVEL PATTERN WILL FEATURE RELATIVELY ZONAL FLOW THROUGH
THE END OF THE WEEK, WITH TWO BACK-TO-BACK EMBEDDED DISTURBANCES
SWEEPING ACROSS THE NATION. THESE DISTURBANCES WILL DRIVE TWO
PROGRESSIVE FRONTAL SYSTEMS THAT WILL BRING PRECIPITATION CHANCES
TO THE NORTHWEST, NORTH-CENTRAL, AND EASTERN U.S., WITH CHANCES
FOR WINTRY PRECIPITATION ACROSS THE NORTHERN TIER. THE PATTERN IS
EXPECTED TO AMPLIFY THIS WEEKEND INTO EARLY NEXT WEEK AS A DEEP
UPPER LOW/TROUGH APPROACHES THE WEST COAST WHILE STRONG RIDGING
DEVELOPS OVER THE INTERMOUNTAIN WEST AND STRONG TROUGHING DEVELOPS
OVER THE EAST. AS THE PATTERN AMPLIFIES, A STRONG ARCTIC COLD FRONT
WILL SINK SOUTH ACROSS THE CENTRAL AND EASTERN U.S., USHERING IN
COLDER TEMPERATURES. MEANWHILE, ANOTHER FRONTAL SYSTEM WILL
GRADUALLY PUSH ONSHORE IN THE NORTHWEST, WHILE A CUTOFF LOW
DEVELOPS OVER THE PACIFIC OFF THE CALIFORNIA COAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT ON THE OVERALL
LARGE SCALE PATTERN THROUGH THE ENTIRE PERIOD, WITH AN EXPECTED
AMOUNT OF UNCERTAINTY IN THE DETAILS AND TIMING OF INDIVIDUAL
SYSTEMS. THE GFS AND ECMWF ARE WELL CLUSTERED WITH ABOVE AVERAGE
AGREEMENT ON THE TIMING AND LOCATION OF EACH SYSTEM. THE CMC SEEMED
TO BE AN OUTLIER AGAIN THIS CYCLE, TRENDING SLIGHTLY DEEPER AND
FASTER AS THE PATTERN AMPLIFIES OVER THE WEEKEND. SPREAD INCREASES
AMONG MODEL SOLUTIONS MONDAY INTO TUESDAY AS A CLOSED UPPER LOW
AND TROUGH SLOWLY APPROACH THE WEST COAST, WHICH RESULTED IN SOME
DIFFERENCES IN PRECIPITATION OVER THE NORTHWEST BASED ON TIMING.
WPC'S FORECAST FAVORED A SLOWER SOLUTION WITH LOWER QPF, WHICH IS
IN LINE WITH MOST DETERMINISTIC GUIDANCE.
WPC'S FORECAST WAS BASED ON A BLEND OF THE DETERMINISTIC GFS,
ECMWF, AND CMC THROUGH THE FIRST HALF OF THE PERIOD, WITH LESS
WEIGHT ON THE CMC GIVEN SOME DIFFERENCES FROM THE CONSENSUS.
ENSEMBLE MEANS FROM THE GEFS AND ECENS WERE ADDED IN INCREASING
AMOUNTS THROUGH THE END OF THE PERIOD TO SMOOTH OUT MODEL
DIFFERENCES. THIS MAINTAINED GOOD AGREEMENT WITH THE PREVIOUS WPC
FORECAST.
..WEATHER/HAZARDS HIGHLIGHTS
A FRONTAL SYSTEM WILL SWEEP QUICKLY ACROSS THE EASTERN U.S. FRIDAY
INTO SATURDAY WITH WIDESPREAD PRECIPITATION CHANCES FROM THE GREAT
LAKES AND NORTHEAST TO THE INTERIOR SOUTHEAST. LOCALLY HEAVY
RAINFALL MAY BE POSSIBLE IN THE WARM SECTOR OF THE SYSTEM OVER THE
OHIO AND TENNESSEE VALLEYS, BUT THE FRONTAL SYSTEM SHOULD BE
PROGRESSIVE ENOUGH TO LIMIT ANY FLASH FLOOD THREAT. ON THE NORTHERN
SIDE OF THE SYSTEM, COLDER AIR WILL ALLOW FOR WINTRY WEATHER
ACROSS THE GREAT LAKES AND NORTHERN NEW ENGLAND.
THE NEXT FRONTAL SYSTEM WILL FOLLOW QUICKLY BEHIND THE FIRST,
ENTERING THE WEST COAST ON FRIDAY AND REACHING THE EAST COAST ON
SUNDAY. PRECIPITATION CHANCES WILL FOCUS OVER THE NORTHERN TIER
WITH THIS SYSTEM, AND MORE WINTRY WEATHER WILL BE POSSIBLE AS
PACIFIC MOISTURE INTERACTS WITH COLD, ARCTIC AIR SURGING SOUTH OUT
OF CANADA ON THE BACKSIDE OF THE SYSTEM. WINTRY WEATHER WILL BE
LIKELY ON FRIDAY IN THE HIGH ELEVATIONS OF THE NORTHWEST AND WILL
BE POSSIBLE SATURDAY AND SUNDAY FROM THE NORTHERN PLAINS TO THE
GREAT LAKES AND NEW ENGLAND. WINTRY WEATHER CHANCES WILL LIKELY
LINGER ACROSS THE GREAT LAKES AND NEW ENGLAND THROUGH EARLY NEXT
WEEK UNDERNEATH A DEEP UPPER LEVEL LOW/TROUGH.
THE COLD AND DRY ARCTIC AIR MOVING SOUTH OUT OF CANADA WILL DRIVE
A COLD FRONT ACROSS THE CENTRAL AND EASTERN U.S. EARLY NEXT WEEK,
WHICH WILL CAUSE TEMPERATURES TO DROP TO 10-15 DEGREES BELOW
AVERAGE. HIGH TEMPERATURES ARE FORECAST TO ONLY REACH THE 30S
ACROSS THE UPPER MIDWEST, GREAT LAKES, AND NORTHERN NEW ENGLAND,
AND SUB-FREEZING LOWS WILL BE POSSIBLE AS FAR SOUTH AS THE CENTRAL
PLAINS AND TENNESSEE VALLEY. MEANWHILE, STRONG RIDGING DEVELOPING
OVER THE INTERMOUNTAIN WEST WILL ALLOW TEMPERATURES TO RISE TO
10-15 DEGREES ABOVE AVERAGE.
THE NEXT SYSTEM WILL SLOWLY APPROACH THE WEST COAST EARLY NEXT
WEEK, CREATING COASTAL PRECIPITATION CHANCES FROM WASHINGTON TO
CENTRAL CALIFORNIA SUNDAY THROUGH TUESDAY. PRECIPITATION MAY SPREAD
TOWARDS THE INTERIOR NORTHWEST MONDAY OR TUESDAY, BUT THE TIMING
AND PROGRESSION OF THIS SYSTEM IS STILL UNCERTAIN.
DOLAN
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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