552
FXUS02 KWBC 240700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT THU OCT 24 2024
VALID 12Z SUN OCT 27 2024 - 12Z THU OCT 31 2024
..GENERAL OVERVIEW
A DIGGING TROUGH IN THE WEST WILL PROMOTE RAIN, HIGH ELEVATION
SNOW, HIGH WINDS AND COOLER TEMPERATURES ACROSS MUCH OF THAT
REGION NEXT WEEK. THIS TROUGH MAY GENERATE HEAVY RAINFALL,
THUNDERSTORMS AND HIGH WINDS OVER PARTS OF THE GREAT PLAINS AND
MISSISSIPPI VALLEY MID-TO-LATE NEXT WEEK AS WELL. A DOWNSTREAM
RIDGE, CENTERED OVER THE BAJA PENINSULA, WILL SUPPORT ABOVE AVERAGE
TEMPERATURES FROM THE PLAINS TO EVENTUALLY THE EAST COAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS WERE FAIRLY WELL CLUSTERED REGARDING THE OVERALL SYNOPTIC
EVOLUTION ACROSS THE LOWER 48 NEXT WEEK. THERE'S SOME UNCERTAINTY
AROUND WHETHER THE UPPER PATTERN WILL SPLIT WITH A SOUTHERN STREAM
TROUGH PROPAGATING THROUGH FOUR CORNERS AND INTO THE PLAINS, WHILE
A NORTHERN STREAM TROUGH GLIDES ACROSS SOUTHERN CANADA. THE
DETERMINISTIC 12Z CANADIAN BECOMES A NOTABLE OUTLIER DUE TO ITS
ATTEMPT TO CREATE A SPLIT FLOW PATTERN WITH AN ANOMALOUS CLOSED
LOW OVER THE FRONT RANGE NEXT WEDNESDAY. THUS, IT WASN'T INCLUDED
IN THE BLEND BEYOND DAY 5. IT'S WORTH NOTING THAT THE AIFS, FUXI
AND PANGU ML MODELS ALSO SIGNAL A SPLIT FLOW PATTERN OVER THE WEST
BEGINNING ON TUESDAY.
A COMBINATION OF THE DETERMINISTIC 12Z ECMWF/CMC/UKMET AND 18Z GFS
WERE UTILIZED IN THE DAYS 3 AND 4 BLENDS WITH THE EC AND GFS
FAVORED. BY DAY 5 THE CANADIAN AND UK ARE REMOVED AND THE 12Z
ECE/CMCE AND 18Z GEFS ARE INTRODUCED TO THE BLEND TO MITIGATE SOME
OF THE MOST ANOMALOUS SPLIT FLOW SIGNALS SEEN IN SOME OF THE
DETERMINISTIC GUIDANCE. A MORE ENSEMBLE MEAN WEIGHTED BLEND IS
CONTINUED THROUGH DAY 7 DUE TO RELATIVELY GOOD RUN-TO-RUN
CONSISTENCY AND NOT MUCH MODEL SPREAD AROUND THE MID-LEVEL TROUGH
OVER THE CENTRAL CONUS..
..WEATHER/HAZARDS HIGHLIGHTS
A LOW PRESSURE SYSTEM WILL ARRIVE OVER THE PACIFIC NORTHWEST ON
SATURDAY, BRINGING WITH IT RAIN, HIGH ELEVATION SNOW TO THE REGION
THROUGH SUNDAY. HIGH WINDS WILL IMPACT THE LEE SIDE OF THE NORTHERN
ROCKIES THIS WEEKEND AS WELL. RAIN, SNOW AND HIGH WINDS EXPAND
INTO THE ROCKIES ON MONDAY AND TUESDAY.
CYCLOGENESIS OVER THE LEE OF THE ROCKIES WILL SUPPORT HIGH WIND
CONCERNS ACROSS PORTIONS OF THE GREAT PLAINS AND MISSISSIPPI
VALLEY EARLY NEXT WEEK. DEPENDING ON HOW DEEP THE UPPER TROUGH GETS
OVER THE PLAINS NEXT WEEK, THERE COULD BE SOME POTENTIAL FOR GULF
OF MEXICO MOISTURE TO INTERACT WITH THE ATTENDANT COLD FRONT OVER
THE PLAINS/MISSISSIPPI VALLEY AND GENERATE HEAVY RAINFALL AND
THUNDERSTORMS.
THE DIGGING TROUGH IN THE WEST WILL BE MIRRORED BY A STAUNCH
DOWNSTREAM RIDGE OVER THE SOUTHERN AND CENTRAL U.S. NEXT WEEK.
KEBEDE
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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