653
FXUS02 KWBC 040700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST SUN FEB 04 2024
VALID 12Z WED FEB 07 2024 - 12Z SUN FEB 11 2024
..OVERVIEW
BROAD AND RENEWED TROUGHING OVER THE WEST INTO NEXT WEEKEND WILL
KEEP THIS REGION QUITE ACTIVE WITH LOWER ELEVATION RAINS AND
MOUNTAIN SNOW, INCLUDING POSSIBLY A COUPLE OF WEAK ATMOSPHERIC
RIVERS INTO CALIFORNIA. MEANWHILE, A STRONG UPPER RIDGE ACROSS THE
CENTRAL U.S. WILL CONTINUE TO SUPPORT WELL ABOVE NORMAL
TEMPERATURES THAT COULD BE RECORD-SETTING ACROSS THE
CENTRAL/NORTHERN PLAINS AND MIDWEST. SHORTWAVES/ENERGY FROM THE
MEAN UPPER TROUGH OVER THE WEST WILL PERIODICALLY EJECT INTO THE
CENTRAL U.S., PUSHING THE RIDGE AND WARM TEMPERATURES SLOWLY
EASTWARD WITH TIME.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE CONTINUES TO BE REASONABLY AGREEABLE ON THE OVERALL
LARGE-SCALE PATTERN DURING THE MEDIUM RANGE PERIOD, BUT THERE ARE
SOME NOTABLE KEY DIFFERENCES WITH SENSIBLE WEATHER IMPACTS. THESE
DIFFERENCES MAINLY FOCUS OUT WEST AS MULTIPLE PIECES OF ENERGY DIG
DOWN THE WESTERN SIDE AND MERGE WITH THE MAIN TROUGH. THERE
REMAINS SOME DETAIL UNCERTAINTIES IN INITIAL ENERGY INTO THE
NORTHWEST WEDNESDAY-THURSDAY, BUT THERE IS BETTER CONSENSUS ON THE
STRENGTH OF THIS SYSTEM THAN PREVIOUS RUNS AT LEAST. THERE IS ALSO
BETTER AGREEMENT ON LEADING ENERGY EJECTING INTO THE UPPER MIDWEST
MID-LATE WEEK.
BIGGER DIFFERENCES ARISE WITH A SECOND SHORTWAVE INTO THE
NORTHWEST ON FRIDAY, WITH THE GFS CONTINUING TO BE MORE ROBUST ON
DIGGING THIS ENERGY SOUTHWARD ALONG THE CA COAST RESULTING IN A
CLOSED LOW OVER THE SOUTHWEST BY NEXT WEEKEND. THE ECMWF AND CMC
ARE WEAKER WITH JUST AN AMPLIFIED TROUGH AND AS A RESULT QUICKER
AS THIS SYSTEM (AND THE ASSOCIATED SURFACE LOW) TRACKS EAST INTO
THE SOUTH-CENTRAL U.S. NEXT SUNDAY. ALSO SOME UNCERTAINTY WITH
TIMING OF A THIRD SHORTWAVE INTO THE NORTHWEST NEXT WEEKEND, WITH
THE CMC ALSO NOTICEABLY FLATTER WITH THIS WAVE.
THE WPC FORECAST FOR TONIGHT WAS ABLE TO UTILIZE A DETERMINISTIC
MODEL BLEND FOR THE FIRST HALF OF THE PERIOD, WITH MORE EMPHASIS
ON THE ECMWF GIVEN BETTER CONSISTENCY WITH THE ENSEMBLE MEANS.
AFTER FRIDAY, REMOVED THE GFS FROM THE BLEND GIVEN ITS OUTLIER
SOLUTION ACROSS THE WEST LATE PERIOD. USED INCREASING AMOUNTS OF
THE ENSEMBLE MEANS LATE PERIOD TO HELP SMOOTH OUT THE DETAIL
DIFFERENCES WHICH ARE IMPOSSIBLE TO RESOLVE AT THESE LONGER TIME
SCALES. OVERALL, THIS APPROACH MAINTAINED GOOD CONTINUITY WITH THE
PREVIOUS WPC FORECAST AS WELL.
..WEATHER/HAZARDS HIGHLIGHTS
GENERAL BROAD TROUGHING OVER THE SOUTHWEST SHOULD KEEP THE WESTERN
U.S. PERIODICALLY ACTIVE WITH WIDESPREAD LOWER ELEVATION
RAIN/MOUNTAIN SNOWS THROUGH MUCH OF THE PERIOD. ON DAY
4/WEDNESDAY, CONTINUED TO HIGHLIGHT A MARGINAL RISK ON THE
EXCESSIVE RAINFALL OUTLOOK ACROSS PARTS OF SOUTHERN ARIZONA WHERE
THE BETTER MOISTURE AND INSTABILITY SHOULD BE LOCATED. THE NEXT
SYSTEM SHOULD BRING ANOTHER ROUND OF RAIN/MOUNTAIN SNOWS TO
CALIFORNIA BY THURSDAY, AND GIVEN HOW SENSITIVE THESE AREAS ARE
AFTER THE STRONG AR CURRENTLY, DID OPT TO INCLUDE A MARGINAL RISK
ACROSS THE NORTHERN/CENTRAL CALIFORNIA COAST ON THE DAY 5 ERO. AS
LEADING ENERGY EJECTS OUT OF THE WESTERN TROUGH INTO THE CENTRAL
U.S. BY THURSDAY, MOISTURE AND INSTABILITY SHOULD HELP FUEL RAIN
AHEAD OF THE COLD FRONT ACROSS THE MID-SOUTH. THOUGH MUCH OF THIS
AREA HAS BEEN FAIRLY WET AS OF LATE, THE SYSTEM SHOULD BE
PROGRESSIVE ENOUGH TO LIMIT THE OVERALL FLASH FLOOD POTENTIAL.
SOME SNOWFALL POTENTIAL ON THE NORTH SIDE OF THE SURFACE CYCLONE
ACROSS THE NORTH-CENTRAL U.S., BUT SOME UNCERTAINTY STILL ON EXACT
AMOUNTS. SHOWERS AND THUNDERSTORMS SHOULD THEN SETTLE ACROSS THE
GULF COAST/SOUTHEAST NEXT WEEKEND, AS THE NEXT SYSTEM MOVES INTO
THE PLAINS WITH YET ANOTHER SLUG OF MOISTURE MOVING INTO THE
PACIFIC NORTHWEST.
THE UPPER RIDGE FROM THE SOUTHERN PLAINS THROUGH GREAT LAKES WILL
SUPPORT A BROAD AREA OF UNSEASONABLY WARM TEMPERATURES OVER THE
CENTRAL U.S. AND MIDWEST THROUGH MUCH OF THE WEEK. CONTINUE TO
EXPECT THE GREATEST ANOMALIES TO BE OVER/NEAR THE UPPER
MIDWEST/GREAT LAKES WHERE MORNING LOWS AND DAYTIME HIGHS MAY BE AS
WARM AS 25-35F ABOVE NORMAL THROUGH AT LEAST FRIDAY WITH
INCREASING POTENTIAL FOR WIDESPREAD DAILY TEMPERATURE RECORDS. IN
CONTRAST, THE SOUTHWEST U.S./CALIFORNIA SHOULD SEE COOL DAYTIME
HIGHS THROUGH THE PERIOD WITH SOME AREAS AROUND 10-15F BELOW
NORMAL ON MULTIPLE DAYS. CLOUDS/PRECIPITATION OVER THE WEST SHOULD
KEEP MORNING LOWS NEAR TO ABOVE NORMAL UNTIL LATER NEXT WEEK.
TEMPERATURES ACROSS THE EAST SHOULD TREND WARMER WITH THE UPPER
RIDGE BUILDING IN, AND DAYTIME HIGHS BY FRIDAY-SATURDAY COULD BE
APPROACHING 10-20 DEGREES ABOVE NORMAL FOR SOME LOCATIONS, WHILE
MODERATING A BIT CLOSER TO NORMAL IN THE MIDWEST.
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 FORECAST, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY
MESSAGES 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
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page