784
FXUS02 KWBC 071907
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
207 PM EST THU NOV 7 2024
VALID 12Z SUN NOV 10 2024 - 12Z THU NOV 14 2024
..WATCHING HURRICANE RAFAEL AS IT TRACKS INTO THE GULF OF MEXICO
..OVERVIEW
THE NATIONAL HURRICANE CENTER CONTINUES TO ISSUE ADVISORIES FOR
HURRICANE RAFAEL AS IT TRACKS ACROSS THE GULF THIS WEEKEND INTO
EARLY NEXT WEEK WHILE WEAKENING AS IT INTERACTS WITH A MEAN UPPER
RIDGE STRETCHING FROM THE BAHAMAS. MODELS AND THE NHC FORECAST
REFLECT RECENT TRENDS TOWARD KEEPING THE SYSTEM WELL SOUTH OF THE
CENTRAL GULF COAST WHILE IT WEAKENS. HOWEVER THE COMBINATION OF
RAFAEL'S MOISTURE AND A FRONTAL SYSTEM SUPPORTED BY AN UPPER LOW
EJECTING NORTHEAST FROM THE PLAINS MAY PRODUCE SOME AREAS OF
LOCALLY HEAVY RAINFALL FROM THE GULF COAST NORTHWARD THROUGH SUNDAY
BEFORE THE FRONT CONTINUES EASTWARD WITH LIGHTER RAIN. FARTHER
WEST, A LARGE SCALE SYSTEM WILL BRING AN EPISODE OF RAIN AND HIGH
ELEVATION SNOW TO THE PACIFIC NORTHWEST THROUGH THE ROCKIES
SUNDAY-MONDAY WITH THIS SYSTEM CONTINUING INTO THE EASTERN HALF OF
THE COUNTRY BY MID-LATE WEEK. ANOTHER SYSTEM SHOULD FOCUS
ADDITIONAL PRECIPITATION OVER THE NORTHWEST BY MIDWEEK. EXPECT
ABOVE NORMAL TEMPERATURES OVER MOST OF THE EAST FOR A MAJORITY OF
THE PERIOD WHILE THE UPPER TROUGH CROSSING THE WEST EARLY NEXT WEEK
WILL BRING A COUPLE DAYS OF COOL TEMPERATURES TO THE REGION.
..GUIDANCE/PREDICTABILITY ASSESSMENT
CONTINUE TO MONITOR LATEST NHC PRODUCTS FOR ADDITIONAL INFORMATION
ON HURRICANE RAFAEL WHICH SHOULD WEAKEN AS IT TRACKS OVER THE GULF
OF MEXICO. THE MOST RECENT NHC FORECAST TRACK SHOWS A PREFERENCE
MORE LIKE THE ECMWF/UKMET WITH A SOUTHWESTERN DIVE TOWARD OR INTO
MEXICO (ALBEIT WITH ONLY A WEAK SURFACE LOW REMAINING). GFS RUNS
HAVE BEEN JUST LINGERING AND WEAKENING THE REMAINING LOW OVER THE
CENTRAL GULF. CMC RUNS THAT BRING RAFAEL ONSHORE INTO THE CENTRAL
GULF COAST ARE CONSIDERED OUTLIERS, BUT HAVE BEEN SOMEWHAT
CONSISTENT FROM RUN TO RUN. MEANWHILE THERE IS A CONTINGENT OF SOME
AI/ML MODELS FROM 00Z THAT TAKE A WEAK RAFAEL NEAR THE
CENTRAL/EASTERN GULF COAST AND ACROSS THE NORTHERN FLORIDA
PENINSULA. DESPITE THE SPREAD, AT LEAST IT IS PRETTY CLEAR THAT THE
CENTER OF RAFAEL ITSELF SHOULD NOT IMPACT THE U.S., ASIDE FROM ITS
TROPICAL MOISTURE SPREADING NORTHWARD.
FARTHER NORTH, GUIDANCE REMAINS FAIRLY AGREEABLE FOR THE CLOSED
UPPER LOW FORECAST TO DEPART FROM THE UPPER MIDWEST EARLY SUNDAY
ONWARD. THERE IS STILL A FAIR AMOUNT OF SPREAD FOR TRAILING
SHORTWAVE ENERGY REACHING THE WEST ON SUNDAY AND CONTINUING
EASTWARD THEREAFTER. OTHER GUIDANCE SUGGESTS THAT THE 12Z CMC
CLOSING OFF AN UPPER LOW IN THE SOUTHEASTERN U.S. ON TUESDAY OR SO
IS PARTICULARLY SUSPECT, THOUGH THE OLDER 00Z CMC THAT SEEMED LIKE
AN OUTLIER IN FORMING A CLOSED UPPER LOW OFF THE EAST COAST BY
MIDWEEK ENDED UP BEING SOMEWHAT SUPPORTED BY THE NEWER 12Z EC/GFS.
REGARDLESS, A PATTERN CLOSE TO THE ENSEMBLE MEANS SEEMS BEST.
THERE ARE SOME TIMING AND AMPLITUDE DIFFERENCES FOR THE LARGE
SCALE UPPER TROUGH NEARING THE WEST COAST BY EARLY MONDAY AND
CONTINUING INTO THE EAST AFTER MIDWEEK, AS WELL AS FOR THE
RESULTING SURFACE EVOLUTION. A BLEND/COMPROMISE APPROACH AMONG
RECENT GFS/ECMWF RUNS AND THEIR MEANS APPEARS MOST REASONABLE FOR
RESOLVING THESE. THE 00Z CMC WAS NOTABLY FASTER BUT THE 12Z CMC WAS
IN SOMEWHAT BETTER AGREEMENT. DETERMINISTIC AND AI/ML MODELS
GENERALLY AGREE WITH SHOWING A SURFACE LOW STRENGTHENING NEAR THE
GREAT LAKES REGION BY THE END OF THE PERIOD. THE NEXT ROUND OF
TROUGHING COMING INTO THE EASTERN PACIFIC BY THURSDAY SHOWS SOME
MINOR DIFFERENCES AS WELL, WITH THE NEW 12Z GFS PERHAPS BEING A
SLOW OUTLIER.
THE WPC FORECAST BLEND FAVORED THE 06Z GFS/00Z ECMWF WITH LESSER
PROPORTIONS OF OTHER MODELS AND ENSEMBLE MEANS EARLY ON. AS THE
FORECAST PROGRESSED, INCREASED THE PROPORTION OF ENSEMBLE MEANS TO
HALF DAY 6 AND MORE DAY 7 AS SPREAD INCREASED.
..WEATHER/HAZARDS HIGHLIGHTS
WHILE CONFIDENCE IS GRADUALLY INCREASING THAT HURRICANE RAFAEL
SHOULD REMAIN WELL SOUTH OF THE GULF COAST AS IT WEAKENS FROM THE
WEEKEND INTO EARLY NEXT WEEK, GUIDANCE CONTINUES TO SHOW AN AXIS OF
ANOMALOUS MOISTURE EXTENDING NORTHWARD FROM THE GULF AND
INTERACTING WITH A FRONT PROGRESSING ACROSS THE EAST-CENTRAL U.S.
(SLOWER AND MORE WAVY OVER THE SOUTH) ALONG WITH SOME LIMITED
INSTABILITY. MODEL/ENSEMBLE SOLUTIONS STILL VARY IN THE DETAILS BUT
CONSISTENCY WITH THE OVERALL PATTERN FAVORS HOLDING VERY CLOSE TO
CONTINUITY FOR THE EXISTING MARGINAL RISK AREA EXTENDING FROM THE
CENTRAL GULF COAST INTO THE OHIO VALLEY/CENTRAL APPALACHIANS IN THE
DAY 4 (SUNDAY-SUNDAY NIGHT) EXCESSIVE RAINFALL OUTLOOK. RAINFALL
LOOKS LIGHTER BY MONDAY THOUGH THERE MAY BE A FEW EMBEDDED HEAVY
SHOWERS ACROSS PARTS OF THE SOUTHEAST. ADDITIONALLY, PARTS OF
FLORIDA MAY SEE SOME INCREASE IN RAINFALL AROUND SUNDAY-MONDAY WITH
A WEAK WAVE BRUSHING THE SOUTHERN PART OF THE STATE.
AN UPPER TROUGH WITH LEADING SURFACE FRONT FOCUSING AN ATMOSPHERIC
RIVER WILL APPROACH THE PACIFIC NORTHWEST AND THEN MOVE INLAND
SUNDAY-MONDAY, BRINGING AN EPISODE OF FOCUSED PRECIPITATION TO THE
REGION. FOR THE DAY 4/SUNDAY ERO THERE IS STILL SOME VARIANCE FOR
RAINFALL AMOUNTS BUT FIRST-GUESS GUIDANCE AND NEUTRAL TO DAMP SOIL
CONDITIONS FAVOR MAINTAINING THE MARGINAL RISK AREA OVER WESTERN
WASHINGTON INTO NORTHWESTERN OREGON. BY DAY 5/MONDAY THE MOISTURE
AXIS SHOULD SINK A LITTLE SOUTH BEFORE PROGRESSING INLAND, WHILE
THE GFS IN PARTICULAR OFFERS POTENTIAL FOR MODEST INSTABILITY.
MONDAY'S ERO THUS COVERS AREAS INTO NORTHERN CALIFORNIA. HOWEVER,
ANOTHER ROUND OF PRECIPITATION MAY IMPACT THE PACIFIC NORTHWEST BY
LATE IN THE DAY 5 ERO PERIOD, SO THIS ISSUANCE OF THE ERO EXTENDS
FARTHER NORTH FROM THE PREVIOUS ISSUANCE TO ADD THE BULK OF THE
PACIFIC NORTHWEST. HIGH ELEVATION SNOW IS LIKELY FROM THE
CASCADES INTO THE SIERRA NEVADA, WHILE EASTWARD PROGRESS OF
MOISTURE AND DYNAMICS WILL ALSO SPREAD SNOW INTO THE NORTHERN-
CENTRAL ROCKIES DURING THE FIRST HALF OF NEXT WEEK. THERE MAY OR
MAY NOT BE A BREAK IN PRECIPITATION AROUND TUESDAY, BUT ADDITIONAL
MEANINGFUL PRECIPITATION IS LIKELY OVER THE PACIFIC NORTHWEST BY
WEDNESDAY-THURSDAY AS ANOTHER SYSTEM APPROACHES.
THE SYSTEM AFFECTING THE WEST EARLY IN THE WEEK WILL PROGRESS
EASTWARD AND BRING SOME AREAS OF PRECIPITATION TO THE EASTERN HALF
OF THE COUNTRY DURING AT LEAST PARTS OF THE TUESDAY-THURSDAY
PERIOD. IMPORTANT LOWER-PREDICTABILITY DETAILS STILL HAVE TO BE
RESOLVED BEFORE CONFIDENCE CAN INCREASE REGARDING SPECIFICS OF
WHERE/WHEN THE GREATEST TOTALS WILL OCCUR. BUT THE LOW TRACK NEAR
THE GREAT LAKES COULD SPREAD TO MODERATE TO HIGH WINDS ESPECIALLY
OVER THE WATERS BUT POSSIBLY FOR SOME LAND AREAS LIKE MICHIGAN'S
UPPER PENINSULA.
WHILE SYSTEM PROGRESSION WILL PROVIDE SOME DAY-TO-DAY VARIABILITY,
MUCH OF THE EASTERN HALF OF THE COUNTRY SHOULD SEE WELL ABOVE
NORMAL TEMPERATURES FROM SUNDAY INTO EARLY NEXT THURSDAY. EXPECT
THE WARMEST ANOMALIES TO BE FOR MORNING LOWS, INCLUDING SOME
READINGS AT LEAST 20F ABOVE NORMAL OVER THE SOUTH EARLY SUNDAY.
BROADEST COVERAGE OF PLUS 10F OR GREATER HIGHS SHOULD BE DURING
MONDAY-WEDNESDAY. THE NORTHERN AND SOUTHERN THIRDS OF THE PLAINS
WILL ALSO SEE A PERIOD OF WARMTH SUNDAY-TUESDAY (AND STILL SOUTHERN
TEXAS ON WEDNESDAY). CORRESPONDING TO THESE RELATIVE ANOMALIES,
THERE WILL BE BETTER POTENTIAL FOR SOME RECORD WARM LOWS VERSUS
MORE ISOLATED RECORDS FOR DAYTIME HIGHS. PARTS OF THE NORTHEAST MAY
BE NEAR NORMAL AT TIMES THOUGH. THE SOUTHERN ROCKIES/HIGH PLAINS
WILL REMAIN CHILLY TO THE EXTENT THAT SNOW COVER LINGERS, WHILE THE
UPPER TROUGH CROSSING THE WEST EARLY NEXT WEEK WILL BRING A BRIEF
PERIOD OF MODERATELY BELOW NORMAL TEMPERATURES.
TATE/RAUSCH
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.PHPSCHICHTEL/HAMRICK
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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