308
FXUS02 KWBC 050657
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
257 AM EDT SAT NOV 05 2022
VALID 12Z TUE NOV 08 2022 - 12Z SAT NOV 12 2022
...POSSIBLY SIGNIFICANT RAIN/MOUNTAIN SNOWS ACROSS PARTS OF
CALIFORNIA AND THE GREAT BASIN INTO TUESDAY, WITH AN OVERALL
CHILLY PATTERN OVER THE WEST THE REST OF THE WEEK...
..OVERVIEW
UPPER TROUGH AMPLIFICATION WILL BE UNDERWAY ALONG THE WEST COAST
AS THE PERIOD BEGINS TUESDAY EVENTUALLY SHIFTING INLAND TOWARDS
THE NORTHERN ROCKIES/HIGH PLAINS MID TO LATER NEXT WEEK. HEAVY
RAIN/MOUNTAIN SNOWS ARE LIKELY ACROSS PARTS OF CALIFORNIA AND THE
GREAT BASIN THROUGH TUESDAY, AS MUCH BELOW NORMAL TEMPERATURES
SPREAD ACROSS THE WEST. MEANWHILE, UPPER LEVEL RIDGING WILL
PREVAIL ACROSS THE EASTERN U.S. THROUGH ABOUT THURSDAY BEFORE SOME
SORT OF HYBRID/SUBTROPICAL FEATURE OVER THE BAHAMAS/FLORIDA MAY
GET WRAPPED UP INTO THE APPROACHING TROUGH FROM THE WEST. THIS
COULD SPREAD MODEST RAINFALL INTO SOME AREAS NEAR THE EAST COAST
LATER NEXT WEEK.
..GUIDANCE AND PREDICTABILITY ASSESSMENT
LATEST GUIDANCE SEEMED AGREEABLE ENOUGH ON THE UPPER PATTERN
THROUGH DAY 4 FOR A PURELY DETERMINISTIC MODEL BLEND. AFTER THIS
TIME, MODELS REALLY BEGIN TO DIVERGE ON THE EVOLUTION OF THE
WESTERN U.S. TROUGH INTO THE CENTRAL U.S. AND THE EAST LATER NEXT
WEEK. THE GUIDANCE DOES SUGGEST THE PATTERN SHOULD REMAIN RATHER
AMPLIFIED THROUGH THE MEDIUM RANGE, BUT POOR RUN TO RUN CONTINUITY
IN ALL OF THE GUIDANCE LENDS TO A VERY LOW CONFIDENCE FORECAST.
THE ECMWF IS THE MOST AMPLIFIED WITH THE LATE WEEK PATTERN SHOWING
CLOSED LOWS OVER BOTH THE MIDWEST AND THE NORTHWEST BY NEXT
SATURDAY/DAY 7. THE GFS IS A LITTLE WEAKER AND FASTER, AND MAYBE
MORE IN LINE WITH THE ENSEMBLE MEANS, AT LEAST FOR NOW. THE CMC
LOOKS REASONABLE IN THE EAST BUT GETS TOTALLY OUT OF PHASE OUT
WEST SHOWING STRONG RIDGING OVER THE WEST COAST WHILE THE BETTER
CONSENSUS SHOWS AT LEAST SOME KIND OF SHORTWAVE INTO THE REGION.
GIVEN THE SPREAD, THE WPC FORECAST TRENDED FAIRLY QUICKLY TOWARDS
THE ENSEMBLE MEANS FOR THE LATTER HALF OF THE PERIOD.
THE EVOLUTION OF A DISTURBANCE IN THE WESTERN ATLANTIC/NEAR THE
BAHAMAS IS UNCERTAIN AS WELL WITH A NUMBER OF DETERMINISTIC AND
ENSEMBLE GUIDANCE CARRYING A CLOSED UPPER LOW ACROSS THE FLORIDA
PENINSULA BEFORE LIKELY GETTING WRAPPED INTO THE EASTERN U.S.
TROUGH. THIS FEATURE WILL NEED TO BE MONITORED IN THE COMING DAYS,
AND THE NATIONAL HURRICANE CENTER IS WATCHING IT FOR ANY POTENTIAL
TROPICAL CHARACTERISTICS.
..WEATHER/HAZARD HIGHLIGHTS
MODEST RAINFALL AND POSSIBLY SIGNIFICANT MOUNTAIN SNOWS WILL BE
ONGOING ACROSS PARTS OF THE WEST AS THE PERIOD BEGINS. THE
HEAVIEST SNOW TOTALS ON TUESDAY ARE LIKELY TO BE IN THE SIERRA
NEVADA IN CALIFORNIA THROUGH THE GREAT BASIN AND CENTRAL ROCKIES
WHERE TOTAL SNOW ACCUMULATIONS IN SOME PLACES COULD MEASURE
SEVERAL FEET. LOCALLY HEAVY RAINS ARE POSSIBLE IN LOWER ELEVATIONS
AND ALONG FAVORABLE UPSLOPE TERRAIN, PARTICULARLY ACROSS PARTS OF
SOUTHERN/COASTAL CALIFORNIA. ANOMALOUS MOISTURE AHEAD OF THIS
TROUGH AS IT MOVES INTO THE CENTRAL U.S. WILL LIKELY SPREAD
MODERATE TO LOCALLY HEAVY RAINFALL INTO PARTS OF THE NORTHERN TIER
WITH SOME SNOW ALSO POSSIBLE ON THE BACKSIDE OF THE LOW IN THE
NORTHERN PLAINS. DESPITE PLENTY OF UNCERTAINTY IN THE DETAILS
STILL, THE DISTURBANCE MOVING TOWARDS FLORIDA MID NEXT WEEK
CONTINUES TO SHOW AN INCREASING THREAT FOR COASTAL AND MARITIME
IMPACTS, INCLUDING HEAVY RAIN, COASTAL FLOODING, HIGH WAVES, AND
RIP CURRENTS. MOISTURE FROM THIS SYSTEM SHOULD MOVE UP THE EAST
COAST LATER IN THE WEEK, ALTHOUGH AMOUNTS AND COVERAGE REMAIN
HIGHLY UNCERTAIN STILL.
MUCH BELOW NORMAL TEMPERATURES ARE EXPECTED TO EXPAND ACROSS THE
WEST THROUGH MUCH OF NEXT WEEK ASSOCIATED WITH THE DEEPENING UPPER
TROUGH. THE COLDEST AIR WILL LIKELY EXTEND FROM WESTERN CANADA
INTO MONTANA WITH RECENT FORECASTS CONSISTENTLY SHOWING HIGHS IN
THAT AREA UP TO 20-40F BELOW NORMAL TUESDAY-THURSDAY, EQUATING TO
DAYTIME HIGHS IN SOME PLACES IN THE TEENS AND SINGLE DIGITS (AND
BELOW ZERO OVERNIGHT LOWS). MANY LOCATIONS OVER THE WEST COULD SEE
DAILY RECORDS FOR COLD HIGHS THROUGH WEDNESDAY. IN CONTRAST, WELL
ABOVE NORMAL TEMPERATURES WILL PROGRESS FROM THE CENTRAL PLAINS TO
THE EAST COAST WITH WIDESPREAD DAILY RECORDS FOR WARM LOWS
POSSIBLE. TUESDAY-WEDNESDAY SHOULD BE THE WARMEST DAYS FOR THE
PLAINS TO THE UPPER MIDWEST WITH READINGS 10-20F OR SO ABOVE
NORMAL. A STRONG COLD FRONT THROUGH THIS REGION BY THURSDAY WILL
USHER IN A MUCH COLDER AIRMASS, WITH HIGH TEMPERATURES BY FRIDAY
AND SATURDAY IN THE PLAINS AS MUCH AS 10 TO 20 DEGREES BELOW
NORMAL.
SANTORELLI
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, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES ARE
AT:
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
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