797
FXUS10 KWNH 231637
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1237 PM EDT TUE JUN 23 2020
VALID JUN 23/1200 UTC THRU JUN 27/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CLOSED LOW OVER ONTARIO/QUEBEC
TROUGH CROSSING THE EASTERN U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE LARGE CLOSED UPPER LOW OVER ONTARIO IS EXPECTED TO SLOWLY
ADVANCE EASTWARD THROUGH WESTERN QUEBEC OVER THE NEXT FEW DAYS AS
THE SOUTHWARD EXTENSION OF A BROADER TROUGH CROSSES THROUGH THE
EASTERN U.S. THIS WILL DRIVE A COLD FRONT TOWARD THE MID-ATLANTIC
AND NEW ENGLAND WEDNESDAY BEFORE THEN SLOWING DOWN AND ONLY VERY
SLOWLY DRIFTING OFFSHORE BY FRIDAY WHILE THE SOUTHWEST TAIL OF THE
FRONT HANGS UP OVER THE SOUTHEAST. MODEL SPREAD AT LEAST
SYNOPTICALLY IS RATHER MINIMAL, BUT THE 00Z CMC WAS SEEN AS BEING
A LITTLE MORE OUT OF TOLERANCE WITH THE CLOSED LOW EVOLUTION
(GENERALLY WEAKER) COMPARED TO THE MODEL CONSENSUS. WILL SUGGEST A
NON-CMC BLEND FOR THE TIME BEING WITH THE MASS FIELD EVOLUTION.
SHORTWAVE CROSSING THE PACIFIC NORTHWEST AND PLAINS
ENERGY DIGGING INTO THE SOUTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z NAM/GFS
CONFIDENCE: AVERAGE
THE LATEST GUIDANCE CONTINUES TO ADVERTISE A SHORTWAVE TROUGH
CROSSING THE PACIFIC NORTHWEST ON WEDNESDAY AND THEN AMPLIFYING
THROUGH THE CENTRAL/NORTHERN ROCKIES GOING THROUGH THURSDAY. AS
THIS IS OCCURRING, SOME OF THE ENERGY WILL BE SEPARATING OUT AND
DIGGING FARTHER SOUTH INTO THE SOUTHWEST. ON FRIDAY, THE NORTHERN
PORTION OF THE ORIGINAL TROUGH WILL EJECT OUT ACROSS THE CENTRAL
AND NORTHERN PLAINS, WITH THE GUIDANCE FAVORING A SOUTHERN STREAM
TROUGH LINGERING NEAR THE FOUR CORNERS REGION. WITH THE INITIAL
SURGE OF THE NORTHERN STREAM PORTION OF THE TROUGH, THE 00Z ECMWF
IS SEEN AS BEING A TAD MORE PROGRESSIVE/WEAKER WITH THE ENERGY.
WITH THE SOUTHERN STREAM ENERGY, THE 00Z ECMWF AND 00Z CMC BOTH
TEND TO HOLD ENERGY BACK FARTHER TO THE WEST OVER THE SOUTHWEST
COMPARED TO THE 12Z NAM/GFS SOLUTIONS. THE 00Z UKMET WITH THIS
ENERGY THOUGH IS THE MOST PROGRESSIVE. OVERALL, THE NAM/GFS CAMP
HAS BETTER ENSEMBLE SUPPORT FOR THE TIME BEING, AND SO A BLEND OF
THESE SOLUTIONS WILL BE PREFERRED WITH BOTH ENERGY STREAMS.
MID-LEVEL ENERGY LINGERING OVER THE LOWER MS VALLEY/TEXAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z NAM/GFS
CONFIDENCE: AVERAGE
A BROAD MID TO UPPER-LEVEL TROUGH IS EXPECTED TO BECOME REMOVED
FROM THE WESTERLIES AND SLOWLY MEANDER OVER THE LOWER MS RIVER
VALLEY AND TX OVER THE NEXT COUPLE OF DAYS. IN THE MEANTIME, A
STRONG MCV OVER NORTH-CENTRAL TX THIS MORNING IS EXPECTED TO
GRADUALLY SETTLE SOUTHEASTWARD TOWARD THE SOUTHEAST TX COASTAL
PLAIN TONIGHT AND BECOME AN ACTIVE FOCUS FOR RENEWED CONVECTION
AND POTENTIALLY SOME VERY HEAVY RAINFALL GOING THROUGH EARLY
WEDNESDAY. THIS ENERGY SHOULD THEN DRIFT EAST THROUGH THURSDAY AND
GENERALLY SHEAR ACROSS THE GULF COAST STATES. HOWEVER, OUT AHEAD
OF THIS ENERGY IS AN MCV WHICH IS CURRENTLY OVER THE WESTERN GULF
OF MEXICO, AND THE MODELS AGREE IN TAKING THAT ENERGY
NORTHEASTWARD AND INLAND ACROSS SOUTHEAST LA AND SOUTHERN MS GOING
THROUGH EARLY WEDNESDAY. THE 12Z NAM IS THE STRONGEST SOLUTIONS
WITH BOTH OF THESE MCVS, WITH THE 12Z GFS AND 00Z CMC A TAD
WEAKER. THE 00Z UKMET/ECMWF SOLUTIONS ARE THE WEAKEST AND APPEAR
TOO WEAK WHEN COMPARED TO THE CURRENT GOES SATELLITE IMAGERY. BY
LATE WEDNESDAY AND EARLY THURSDAY, THE GUIDANCE FAVORS ADDITIONAL
SHORTWAVE/MCV ENERGY DROPPING SOUTHEAST THROUGH TX WHICH WILL HELP
TO REINFORCE THE BROADER MID TO UPPER-LEVEL TROUGH OVER THE
REGION. THE 00Z CMC APPEARS TOO STRONG THOUGH WITH THIS ENERGY AND
CONSEQUENTLY ENDS UP WITH A CLOSED LOW CENTER MOVING INTO THE
LOWER MS VALLEY FRIDAY WHEREAS THE MODEL CONSENSUS FAVORS A
BROADER WEAKNESS STILL BACK OVER CENTRAL/EASTERN TX. THE
PREFERENCE WILL BE TOWARD A BLEND OF THE NAM AND GFS WITH THE MCVS
THROUGH THE PERIOD, AND WITH THE BROADER TROUGH GIVEN THE BETTER
NAM/GFS REPRESENTATION/INITIALIZATION OF THE CURRENT MCV ENERGY
OVER TX AND THE WESTERN GULF OF MEXICO.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
ORRISON
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