329
FXUS10 KWNH 091626
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1225 PM EDT THU APR 09 2020
VALID APR 09/1200 UTC THRU APR 13/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION...WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP CYCLONE IMPACTING THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS BLEND
CONFIDENCE: ABOVE AVERAGE
AN ANOMALOUSLY DEEP CLOSED LOW CROSSING THE GREAT LAKES WILL
DEEPEN AND TAKE ON A NEGATIVE TILT AS IT APPROACHES THE NORTHEAST
THIS AFTERNOON/EVENING. MEANWHILE, LOW PRESSURE CROSSING THE
INTERIOR OF NY STATE AND NEW ENGLAND WILL CONSOLIDATE OVER COASTAL
AREAS OF MAINE THIS EVENING AND DEEPEN INTO AN INTENSE LOW CENTER.
THE 12Z GFS IS OVERALL A TAD DEEPER THAN THE 12Z NAM AND THE 00Z
NON-NCEP SOLUTIONS. THE GFS ALSO TRACKS ITS SURFACE LOW A TAD
FARTHER INLAND OVER MAINE VERSUS THE MORE CONCENTRATED LOW CENTER
EVOLUTION ALONG THE MAINE COAST THAT THE REMAINING GUIDANCE
FAVORS. THIS RESULTS IN THE GFS HAVING A SOMEWHAT STRONGER WARM
NOSE WRAPPING FARTHER INLAND. THE PREFERENCE WILL BE TOWARD A
NON-GFS BLEND AT THIS TIME.
..SLOW-MOVING CLOSED LOW ACROSS THE SOUTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE MODELS GRADUALLY EJECT THE LARGE, SLOW-MOVING CUT-OFF SOUTHERN
STREAM LOW OVER SOUTHERN CALIFORNIA OFF TO THE EAST OVER THE NEXT
COUPLE OF DAYS. THE ENERGY IS EXPECTED TO OPEN UP INTO A
PROGRESSIVE SHORTWAVE TROUGH OVER THE SOUTHERN PLAINS BY SATURDAY
WHICH WILL THEN LIFT NORTHEAST AND GO NEGATIVE TILT OVER LOWER MS
VALLEY AND MID-SOUTH BY SUNDAY AS IT COMES UNDER THE INFLUENCE OF
STRONGER NORTHERN STREAM HEIGHT FALLS DROPPING DOWN OVER THE
MIDWEST. THE 12Z GFS, JUST LIKE ITS PREVIOUS RUNS, CONTINUES TO BE
THE FASTEST SOLUTION AS THE ENERGY EJECTS OUT ACROSS THE SOUTH.
WITH ITS FASTER HEIGHT FALL PROGRESSION, THE GFS IS ALSO FASTER
WITH ITS SURFACE FRONTAL PROGRESSION AND WAVE ACTIVITY, AND
ACTUALLY ENDS UP WITH A SOMEWHAT STRONGER SURFACE LOW COMPARED TO
THE OTHER MODELS BY SUNDAY. THE 12Z NAM IS GENERALLY IN AGREEMENT
WITH THE 00Z NON-NCEP MODELS WITH A MODESTLY SLOWER TIMING AND
MODESTLY WEAKER SURFACE REFLECTION. THE LATEST ENSEMBLES MEANS
SUGGEST A SOLUTION GENERALLY A LITTLE SLOWER THAN THE GFS FOR THE
TIME BEING, SO THE LATEST PREFERENCE WILL BE FOR A NON-GFS BLEND
WITH THIS ENERGY.
..UPPER LEVEL TROUGH/COLD FRONT REACHING THE NORTHWEST
..DROPPING THROUGH THE NORTHERN PLAINS/MIDWEST ON SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z CMC/UKMET AND ECMWF
CONFIDENCE: AVERAGE
SHORTWAVE ENERGY ALONG THE SOUTHERN COAST OF ALASKA WILL PROGRESS
EASTWARD TO THE YUKON TERRITORY, AND WITH THE ACCELERATING/EXITING
JET, THE UPSTREAM RIDGE WILL BREAK DOWN AND ALLOW FOR GREATER
PROPAGATION EAST AND THEN SOUTHWARD ACROSS SOUTHWESTERN CANADA.
THE HEIGHT FALLS WILL OVERSPREAD THE LEE OF THE CANADIAN ROCKIES
AND THEN THE NORTHERN HIGH PLAINS, AND SUPPORT A SURFACE COLD
FRONT DROPPING SOUTHEASTWARD ACROSS THE NORTHERN PLAINS AND
MIDWEST BY SUNDAY. THE 12Z NAM TENDS TO BE A LITTLE MORE
AGGRESSIVE WITH ITS HEIGHT FALLS OVER THE MIDWEST BY SUNDAY, AND
THE 12Z GFS MAY BE A LITTLE TOO FAST WITH ITS SURFACE FRONTAL
PROGRESSION, SO THE PREFERENCE WITH THIS ENERGY WILL BE TO
GENERALLY MINIMIZE THE NAM/GFS CAMPS, AND FAVOR MORE WEIGHTING
TOWARD THE 00Z NON-NCEP SOLUTIONS FOR NOW GIVEN BETTER
CLUSTERING/ENSEMBLE SUPPORT.
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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