728
FXUS02 KWBC 251923
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
323 PM EDT FRI OCT 25 2024
VALID 12Z MON OCT 28 2024 - 12Z FRI NOV 01 2024
...MODERATE TO HEAVY SNOW THREAT INCREASING FOR THE NORTHERN TO CENTRAL
ROCKIES AND NEARBY HIGH PLAINS TUESDAY-WEDNESDAY...
...MODERATE TO HEAVY RAIN THREAT INCREASING FROM THE PLAINS TO THE
MIDWEST DURING THE LATTER HALF OF NEXT WEEK...
..GENERAL OVERVIEW
AN AMPLIFIED UPPER-LEVEL TROUGH SET TO DIG INTO THE WEST THIS
WEEKEND WILL SPREAD HIGHLY UNSETTLED WEATHER ACROSS MUCH OF THE
WESTERN U.S. EARLY NEXT WEEK TO INCLUDE HIGH-ELEVATION SNOW, GUSTY
WINDS AND COLDER TEMPERATURES. THIS TROUGH WILL THEN PUSH EASTWARD
AGAINST A WARM AND EXPANDING UPPER RIDGING OVER THE CENTRAL TO
EASTERN U.S., RESULTING IN A WAVY SHARP FRONT ACROSS THE MID-
SECTION OF THE COUNTRY WHERE A MODERATELY HEAVY RAIN EVENT APPEARS
TO EMERGE FROM THE PLAINS THROUGH THE MISSISSIPPI VALLEY AND
MIDWEST FOR THE LATTER HALF OF NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
LATEST GFS/ECMWF/UKMET/CANADIAN MODEL GUIDANCE SEEMS WELL CLUSTERED
THROUGH EARLY TO MIDDLE OF NEXT WEEK AND ENJOYS GOOD ENSEMBLE AND
NATIONAL BLEND OF MODEL (NBM) SUPPORT, BOLSTERING FORECAST
CONFIDENCE. A COMPOSITE SOLUTION SEEMS TO WELL MITIGATE LINGERING
SYSTEM TIMING DIFFERENCES NEXT WEEK, ALBEIT WITH FAVORED SLOW
TRANSITION FROM THE MODELS TO A BLEND OF THE NBM AND COMPATIBLE
GEFS/ECMWF ENSEMBLE MEANS. THIS HOLDS GOOD WPC PRODUCT CONTINUITY.
TIMING ISSUES BECOME MORE NOTICEABLE TOWARD THE END OF NEXT WEEK
REGARDING THE NEXT UPPER TROUGH MOVING THROUGH THE NORTHWEST BUT
AGREEMENT REMAINS RATHER GOOD REGARDING A LOW PRESSURE WAVE
FORECAST TO TRACK ACROSS THE GREAT LAKES TOWARD NEW ENGLAND
THURSDAY INTO FRIDAY.
IN ADDITION, IT SHOULD BE NOTED THAT FOR THE POTENTIAL MODERATE/HEAVY
RAINFALL ACROSS THE MID-SECTION OF THE COUNTRY MIDWEEK, THE
ECMWF/CMC CLUSTER HAS BEEN TRENDING TOWARD A MORE SOUTHERN FOCUS
OF THE HEAVIEST RAINS OVER THE SOUTHERN PLAINS WHILE THE GFS/GEFS
CLUSTER APPEARS TO BEGIN TRENDING IN THAT DIRECTION AS WELL.
..WEATHER/HAZARDS HIGHLIGHTS
A COLD FRONT ASSOCIATED WITH A DIGGING UPPER-LEVEL TROUGH FROM
THE PACIFIC WILL BE STEADILY MOVING THROUGH THE WESTERN U.S.
EARLY NEXT WEEK. PERIODS OF RAIN, HIGH-ELEVATION SNOW, WINDY AND
COLDER CONDITIONS ARE EXPECTED TO OVERSPREAD MUCH OF THE REGION
ALONG/BEHIND THE FRONT. LOCALLY HIGH WINDS COULD IMPACT PORTIONS OF
THE SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS AS THE COLDER
AIRMASS DIGS INTO THE REGION. THIS MAY ALSO LEAD TO THE ONSET OF
FROST/FREEZE FOR SOME OF THESE AREAS FOR THE FIRST TIME THIS
SEASON.
MODEST CYCLOGENESIS ACROSS THE CANADIAN PRAIRIES WILL ADVANCE A
FRONT ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST THROUGH EARLY
NEXT WEEK. THIS FRONT IS FORECAST TO SHARPEN WITH TIME AS IT
CONTINUES TO PUSH AGAINST AN EXPANSIVE HIGH PRESSURE SYSTEM
FORECAST TO ANCHOR ACROSS THE EASTERN AND SOUTHERN U.S. SNOW WILL
APPEAR TO LINGER OVER THE NORTHERN TO CENTRAL ROCKIES AND INTO THE
NORTHERN HIGH PLAINS BEHIND A LOW PRESSURE WAVE WHERE ACCUMULATING
SNOWFALL APPEARS LIKELY, ESPECIALLY FOR THE HIGHER ELEVATIONS OF
WYOMING TUESDAY INTO WEDNESDAY. SOME OF THE ACCUMULATING SNOW COULD
SPILL INTO THE NEARBY HIGH PLAINS AND BLACK HILLS AS WELL. AHEAD
OF THE SHARPENING FRONT, A LONG FETCH OF RETURN FLOW FROM THE GULF
OF MEXICO APPEARS TO INITIATE AND SUPPORT A MODERATE TO HEAVY RAIN
EVENT FROM THE CENTRAL/SOUTHERN PLAINS THROUGH THE MID-MISSISSIPPI
VALLEY AND INTO THE MIDWEST WITH EMBEDDED THUNDERSTORMS BY MIDWEEK
NEXT WEEK ESPECIALLY IF A LOW PRESSURE WAVE IS ABLE TO CONSOLIDATE
ALONG THE FRONT. THE FRONT IS THEN FORECAST TO STALL ACROSS THE
SOUTHERN PLAINS WHERE MODERATE TO HEAVY RAINFALL COULD LINGER INTO
LATE NEXT WEEK. IN THE MEANTIME, PRECIPITATION ASSOCIATED WITH THE
NEXT PACIFIC SYSTEM IS FORECAST TO MOVE INTO THE PACIFIC NORTHWEST
THROUGH THE LATTER HALF OF NEXT WEEK WITH HIGH-ELEVATION SNOW
REACHING INTO THE NORTHERN ROCKIES.
THE DIGGING TROUGH IN THE WEST WILL USHER IN AND SUSTAIN COLDER
THAN NORMAL TEMPERATURES FOR PRETTY MUCH THE ENTIRE WESTERN U.S.
THROUGH LATE NEXT WEEK. IN CONTRAST, HIGH TEMPERATURES REACHING
INTO THE UPPER 80S TO LOWER 90S WILL CHALLENGE SOME DAILY RECORDS
ACROSS THE SOUTHERN PLAINS TO THE MID-SOUTH EARLY NEXT WEEK. THE
EXPANDING UPPER RIDGE TOGETHER WITH A LONG FETCH OF STRONG AND
GUSTY SOUTHERLY WINDS AT THE SURFACE WILL SEND THE WARMTH WELL TO
THE NORTH AND EAST, REACHING INTO THE GREAT LAKES AND EVENTUALLY
NEW ENGLAND THROUGH THE MIDDLE AND LATE NEXT WEEK. HIGH
TEMPERATURES REACHING WELL UP INTO THE 70S TO NEAR 80 DEGREES
WILL BE ENOUGH TO SET SOME NEW DAILY RECORD HIGH TEMPERATURES FROM
THE GREAT LAKES TO NEW ENGLAND WEDNESDAY AND THURSDAY.
KONG/SCHICHTEL
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab HPC Page Main Text Page