038
FXUS02 KWBC 060658
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
158 AM EST WED NOV 6 2024
VALID 12Z SAT NOV 09 2024 - 12Z WED NOV 13 2024
...WATCHING HURRICANE RAFAEL AS IT TRACKS INTO THE GULF OF MEXICO
TOWARD THE CENTRAL GULF COAST...
..OVERVIEW
AN UPPER HIGH WILL REMAIN ANCHORED OVER OR JUST NORTH OF THE
BAHAMAS THROUGH THE PERIOD, WITH RIDGES EXTENDING OUT FROM THIS
HIGH INTO THE GULF OF MEXICO AND EASTERN U.S. AT TIMES. THE
NATIONAL HURRICANE CENTER CONTINUES TO ISSUE ADVISORIES FOR
HURRICANE RAFAEL WHICH SHOULD WEAKEN IN A FEW DAYS AS IT TRACKS
CLOSER TO THE CENTRAL GULF COAST. 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. MEANWHILE, A SERIES OF
PACIFIC SYSTEMS WILL INCREASE COVERAGE OF RAIN AND HIGHER ELEVATION
SNOW OVER THE WEST FROM THE WEEKEND INTO EARLY NEXT WEEK. MUCH OF
THE EAST SHOULD SEE ABOVE NORMAL TEMPERATURES THROUGH THE PERIOD
WHILE THE SOUTHERN ROCKIES WILL START THE WEEKEND ON THE CHILLY
SIDE AND COOLER TEMPERATURES WILL SPREAD ACROSS THE WEST NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
FOR HURRICANE RAFAEL, THERE IS STILL CONSIDERABLE GUIDANCE SPREAD
(AS THE 00Z UKMET SWITCHED TO A WESTERN/SOUTHWESTERN GULF TRACK
VERSUS BRINGING IT TO THE CENTRAL GULF COAST) BUT OVERALL THE
MAJORITY OF DYNAMICAL/MACHINE LEARNING (ML) GUIDANCE IS GRADUALLY
NARROWING THE SOLUTION SPREAD WITH A TRACK APPROACHING THE CENTRAL
GULF COAST. THE SYSTEM SHOULD ALSO WEAKEN AS IT REACHES THE
NORTHERN GULF, WITH LATEST GUIDANCE UNSURE OF WHETHER IT WILL GET
LIFTED NORTHWARD/NORTHEASTWARD OR CONTINUE MEANDERING OVER THE
GULF. CONTINUE TO MONITOR LATEST NHC PRODUCTS FOR ADDITIONAL
INFORMATION ON RAFAEL.
A MODEL AVERAGE HAS PROVIDED A FAIRLY CONSISTENT FORECAST OF THE
UPPER LOW EJECTING FROM THE PLAINS, BUT GUIDANCE HAS BEEN MORE
ERRATIC WITH DETAILS OF A SHORTWAVE THAT ENTERS WESTERN NORTH
AMERICA DURING THE WEEKEND AND MAY HAVE SOME INFLUENCE ON THE
REMAINING UPPER LOW ENERGY BY THE START OF NEXT WEEK (WITH SOME
DEBATE OVER WHICH ENERGY MAY BE MORE PRONOUNCED AT THAT TIME).
THIS LEADS TO UNCERTAINTY FOR SOME DETAILS OF THE FRONTAL SYSTEM
REACHING THE NORTHEAST.
THERE ARE CONTINUED TIMING AND AMPLITUDE DIFFERENCES FOR THE LARGER
SCALE TROUGH MOVING INTO/THROUGH THE WEST EARLY NEXT WEEK, WITH GFS
RUNS LEANING SLOWER AND ECMWF FASTER. LATEST ML MODELS SHOW A
SIMILAR SPREAD, ARGUING FOR A BLEND/COMPROMISE APPROACH. THIS ALSO
MITIGATES ISSUES FOR HOW ENERGY MAY BE DISTRIBUTED WITHIN THE UPPER
TROUGH BY THE MIDDLE OF NEXT WEEK, WITH INDIVIDUAL SOLUTIONS
RANGING BETWEEN GREATER DYNAMICS IN THE NORTHERN PART OF THE
TROUGH, OR FARTHER SOUTH, TO AN EVENLY PHASED TROUGH. A COMPROMISE
ALSO LOOKS BEST FOR THE NEXT SYSTEM THAT MAY COME INTO THE PICTURE
OVER THE NORTHEASTERN PACIFIC BY NEXT WEDNESDAY.
OVERALL A BLEND OF THE 12Z/18Z GFS, 12Z ECMWF, AND THE 18Z GEFS/12Z
ECENS MEANS PROVIDED THE MOST AGREEABLE STARTING POINT FOR THE
FORECAST OVERALL, WITH MORE OPERATIONAL MODEL WEIGHT EARLY NEARLY
EVEN MODEL/MEAN WEIGHT BY NEXT TUESDAY-WEDNESDAY.
..WEATHER/HAZARDS HIGHLIGHTS
THE COMBINATION OF THE PLAINS SYSTEM PUSHING INTO THE MISSISSIPPI
VALLEY AND MOISTURE FROM RAFAEL, WHICH IS FORECAST TO BE SOUTH OF
THE CENTRAL GULF COAST BY THE WEEKEND, WILL LEAD TO THE POTENTIAL
FOR SOME AREAS OF HEAVY RAINFALL BETWEEN THE CENTRAL GULF COAST AND
LOWER OHIO VALLEY. WHILE THERE IS STILL SPREAD IN THE GUIDANCE FOR
WHERE THE MOISTURE AXIS WILL BE, CLUSTERING IS SIGNIFICANTLY
IMPROVED FROM JUST 24 HOURS AGO. THE DAY 4 EXCESSIVE RAINFALL
OUTLOOK VALID SATURDAY-SATURDAY NIGHT MAINTAINS A MARGINAL RISK
AREA ACROSS THIS REGION. IT WILL TAKE ADDITIONAL TIME TO SEE IF
GUIDANCE RESOLVES DETAILS SHARPLY ENOUGH TO MERIT AN EMBEDDED
SLIGHT RISK. BY SUNDAY, GUIDANCE SIGNALS BECOME MORE DIFFUSE ALONG
THE FRONT IN THE EAST-CENTRAL U.S., LEAVING JUST THE CENTRAL GULF
COAST REGION WITH SOMEWHAT ELEVATED POTENTIAL FOR HEAVY RAINFALL
DUE TO THE CONTINUED PROXIMITY OF RAFAEL AND MERITING A MARGINAL
RISK AREA IN THE DAY 5 ERO. SOME RAINFALL MAY LINGER BEYOND SUNDAY
BUT MOST OF THE EAST SHOULD TREND DRIER BY MONDAY-TUESDAY. ALSO OF
NOTE, A WAVE TRACKING FROM THE SOUTHERN BAHAMAS INTO THE EASTERN
GULF MAY INCREASE RAINFALL OVER FLORIDA AROUND SUNDAY-MONDAY.
THE WEST WILL SEE A WETTER REGIME WITH HIGH ELEVATION SNOW,
STARTING IN THE PACIFIC NORTHWEST AND THEN SPREADING FARTHER
SOUTH INTO PARTS OF CALIFORNIA AND EAST INTO THE ROCKIES. HIGHEST
TOTALS SHOULD BE IN THE SUNDAY-MONDAY TIME FRAME WITH A VIGOROUS
UPPER TROUGH AND FRONTAL SYSTEM APPROACHING/REACHING THE AREA.
WHILE THERE IS STILL A FAIR AMOUNT OF SPREAD FOR QPF MAGNITUDES,
FIRST-GUESS GUIDANCE IS SHOWING ENOUGH OF A SIGNAL TO INTRODUCE A
MARGINAL RISK AREA IN THE DAY 5 ERO OVER PARTS OF THE PACIFIC
NORTHWEST WHERE INITIAL SOIL CONDITIONS ARE NEUTRAL TO DAMP.
ANOTHER SYSTEM MAY BRING ADDITIONAL FOCUSED PRECIPITATION TO THE
PACIFIC NORTHWEST NEXT WEDNESDAY. DEPENDING ON WESTERN UPPER TROUGH
PROGRESSION, SOME RAINFALL MAY DEVELOP OVER THE CENTRAL U.S. BY THE
MIDDLE OF NEXT WEEK.
EXCEPT FOR THE GREAT LAKES INTO NEW ENGLAND DURING THE WEEKEND,
THE EASTERN HALF OF THE COUNTRY WILL LIKELY SEE ABOVE NORMAL
TEMPERATURES THROUGH THE PERIOD. WARMEST ANOMALIES SHOULD BE FOR
MORNING LOWS, REACHING 20-25F ABOVE NORMAL ON ONE OR MORE DAYS OVER
THE SOUTH AND EXTENDING A LITTLE FARTHER NORTHEASTWARD AT TIMES.
COVERAGE OF PLUS 10-15F ANOMALIES FOR HIGHS SHOULD INCREASE GOING
FROM THE WEEKEND INTO THE FIRST HALF OF NEXT WEEK. CORRESPONDING TO
THESE RELATIVE ANOMALIES, THERE WILL BE BETTER POTENTIAL FOR SOME
RECORD WARM LOWS VERSUS MORE ISOLATED RECORDS FOR DAYTIME HIGHS.
THE NORTHERN PLAINS WILL ALSO BE WELL ABOVE NORMAL UNTIL A COOLING
TREND TUESDAY-WEDNESDAY, WHILE THE SOUTHERN PLAINS WILL BE WARMEST
EARLY NEXT WEEK. CHILLY TEMPERATURES OVER THE SOUTHERN ROCKIES/HIGH
PLAINS WILL GRADUALLY MODERATE MUCH OF THE WEST WILL BE NEAR
NORMAL DURING THE WEEKEND. THE UPPER TROUGH PUSHING INTO THE WEST
NEXT WEEK WILL EXPAND THE COVERAGE OF BELOW NORMAL TEMPERATURES
FROM WEST TO EAST.
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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