571
FXUS02 KWBC 142037
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
433 PM EDT MON MAR 14 2022
VALID 12Z THU MAR 17 2022 - 12Z MON MAR 21 2022
1830 UTC UPDATE...
NO MAJOR CHANGES TO THE FORECAST THINKING FROM THE OVERNIGHT SHIFT
FOLLOWING THE 00Z/06Z MODEL RUNS. THE LAST FEW RUNS OF THE GFS
(INCLUDING THE MOST RECENT 12Z RUN FROM TODAY) CONTINUES TO BE
STRONGER WITH SOUTHERN STREAM ENERGY THROUGH THE PLAINS/MIDWEST
LATE THIS WEEK, RESULTING IN A MORE WRAPPED, DEEPER, AND FARTHER
NORTH SURFACE LOW PLACEMENT. AGAIN, TODAYS UPDATE TO THE WPC
FORECAST LEANED MORE TOWARDS THE BETTER CLUSTERED ECMWF, CMC, AND
UKMET SOLUTIONS FOR THIS SYSTEM. ELSEWHERE, AN ECMWF/GFS BLEND
WITH THE ENSEMBLE MEANS SEEMS TO CONTINUE TO SERVE WELL WITH THE
NEXT TROUGH/CLOSED LOW IN THE SOUTHWEST EARLY NEXT WEEK AMIDST
GOOD LARGE SCALE AGREEMENT BUT PLENTY OF DETAIL UNCERTAINTIES
STILL TO BE WORKED OUT. SEE PREVIOUS DISCUSSION BELOW FOR
ADDITIONAL INFORMATION CONCERNING THE MEDIUM RANGE PERIOD FORECAST
AND ASSOCIATED WEATHER/HAZARD THREATS.
SANTORELLI
..PREVIOUS DISCUSSION ISSUED AT 0628 UTC
..OVERVIEW
A FAST, PROGRESSIVE FLOW PATTERN WITH INCREASING AMPLITUDE IS
EXPECTED TO EVOLVE OVER THE CONUS THROUGHOUT THE FORECAST PERIOD.
THE INITIAL SYSTEM OVER THE SOUTHEAST THURSDAY WILL QUICKLY DEPART
TO THE NORTHEAST OFFSHORE WHILE ANOTHER STORM SYSTEM BREWS OVER
THE SOUTHERN PLAINS THURSDAY/FRIDAY BEFORE LIFTING INTO THE GREAT
LAKES BY NEXT WEEKEND. BY LATE IN THE WEEKEND TO EARLY NEXT WEEK,
A MUCH STRONGER AND AMPLIFIED TROUGH WILL PROGRESS THROUGH THE
WESTERN U.S., REACHING THE PLAINS BY EARLY NEXT WEEK. THIS COULD
BRING WIDESPREAD, BENEFICIAL RAINS TO THE WESTERN U.S. AND EVOLVE
INTO A STRONG STORM SYSTEM JUST BEYOND THE FORECAST PERIOD. NO
SIGNIFICANT COLD AIR OUTBREAKS ARE ANTICIPATED AND TEMPERATURES
WILL GENERALLY OSCILLATE BETWEEN NEAR NORMAL AND MUCH ABOVE NORMAL
AHEAD OF THE VARIOUS WAVES OF LOW PRESSURE.
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
WHILE LARGE SCALE FEATURES IN THE LATEST DETERMINISTIC AND
ENSEMBLE GUIDANCE SHOW AVERAGE TO ABOVE AVERAGE PREDICTABILITY AND
AGREEMENT, THERE ARE SOME NOTABLE SURFACE DIFFERENCES THAT HAVE
IMPACTS ON TIMING AND SENSIBLE WEATHER. INITIALLY, THE FIRST AREA
OF MODEL DIFFERENCES LIES WITH THE NEUTRALLY TITLED SHORTWAVE
TROUGH COMING THROUGH THE PLAINS LATE IN THE WEEK. THE ASSOCIATED
SURFACE LOW HAS SIGNIFICANT LATITUDINAL DIFFERENCES WITH THE GFS
BEING A FAST, PROGRESSIVE AND NORTHERN OUTLIER COMPARED TO THE
SLOWER ECMWF/UKMET/CMC. THIS IS LARGELY DRIVEN BY ITS DEEPER,
STRONGER 500 MB TROUGH THAT TAKES ON A SLIGHT NEGATIVE TILT AS IT
SWINGS THROUGH THE MIDWEST. FOR NOW, THE WPC BLEND FAVORED THE
SLOWER, NON-GFS SOLUTION BUT DID INCLUDE SOME OF IT TO MAINTAIN
CONTINUITY. BEYOND THAT SYSTEM, THE FLOW PATTERN TAKES ON MORE
AMPLITUDE WITH THE WESTERN U.S. LIKELY TO SEE A DIGGING TROUGH
THAT EVENTUALLY CLOSES OFF AROUND THE FOUR CORNERS REGION BY THE
END OF THE PERIOD. WHILE THERE ARE SOME TIMING DIFFERENCE, BOTH
THE ECMWF/GFS AND ECENS/GEFS MEANS SHOW FAIRLY GOOD AGREEMENT IN
THIS SETUP. AS THE ENERGY REACHES THE PLAINS, STRONG CYCLOGENESIS
IS POSSIBLE. OVERALL, THE WPC BLEND INCORPORATED THE 12Z ECMWF/CMC
AND 18Z GFS FOR DAYS 3-5 THEN INCLUDED MORE OF THE ECENS/GEFS FOR
DAYS 6-7 GIVEN THE TYPICAL MODEL SPREAD.
..WEATHER HIGHLIGHTS/THREATS
THE SLOW-MOVING GULF TO SOUTHEAST COASTAL SYSTEM WILL BRING
WIDESPREAD LIGHT TO MODERATE RAINFALL TO THE COASTAL REGIONS
THURSDAY BEFORE THE SYSTEM MOVES WELL OFFSHORE INTO FRIDAY. THE
NEXT SYSTEM MOVING THROUGH THE PLAINS COULD BRING SOME MODERATE TO
LOCALLY HEAVY RAINFALL AS WELL AS POTENTIAL WINTER WEATHER ON THE
NORTHWEST/COLD SIDE, THOUGH THE AFOREMENTIONED MODEL DIFFERENCES
AND MARGINALLY SUPPORTIVE THERMAL PROFILES FOR WINTER WEATHER WILL
KEEP THE LATEST WINTER WEATHER OUTLOOK FOR DAY 5 GENERALLY VERY
LOW. FINALLY, THE ACTIVE/UNSETTLED WEATHER GREETING THE WESTERN
U.S. TOWARD THE END OF THE PERIOD WILL BE MOSTLY BENEFICIAL AND
WELCOMED PRECIPITATION. TEMPERATURES LOOK TO BE MOSTLY NEAR TO
ABOVE NORMAL, AHEAD OF THE VARIOUS WAVES OF LOW PRESSURE. SOME
DIPS TO BELOW NORMAL READINGS ARE POSSIBLE ACROSS THE WEST AND
INTERIOR WEST AS THE NEXT LARGE SCALE WEATHER SYSTEM MOVES THROUGH
THANKS TO CLOUDS AND PRECIPITATION.
TAYLOR
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
HAZARDS:
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE CENTRAL GREAT BASIN,
THE GREAT LAKES, THE NORTHEAST,
CALIFORNIA, AND THE SOUTHWEST, SAT, MAR 19.
- HEAVY RAIN ACROSS PORTIONS OF THE CENTRAL PLAINS, THE MIDDLE
MISSISSIPPI VALLEY, THE LOWER
MISSISSIPPI VALLEY, AND THE SOUTHERN PLAINS, MON, MAR 21.
- FLOODING LIKELY ACROSS PORTIONS OF THE NORTHERN ROCKIES AND THE
NORTHERN GREAT BASIN.
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/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
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