290
FXUS10 KWNH 151736
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1235 PM EST FRI NOV 15 2019
VALID NOV 15/1200 UTC THRU NOV 19/0000 UTC
A..SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..UPPER LOW OVER THE SOUTHEAST
..EAST COAST COASTAL LOW EVOLUTION
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z HREF (MINUS NMMB) AND 00Z CMC/ECMWF BLEND <36 HRS
00Z CMC/ECMWF BLEND >36 HRS
CONFIDENCE: AVERAGE...BECOMING BELOW AVERAGE AFTER 36 HOURS
AN UPPER LOW DEEPENING OVER THE SOUTHEAST WILL MOVE EAST AND
FOSTER MULTIPLE AREAS OF CYCLOGENESIS OFF THE SOUTHEAST COASTLINE
TONIGHT THROUGH EARLY SATURDAY. ALL OF THE MODELS STRONGLY SUPPORT
LOW PRESSURE BECOMING TUCKED IN RELATIVELY CLOSE SOUTHEAST NC
THROUGH THIS PERIOD, BUT THEREAFTER, THE 12Z NAM BECOMES AN
OUTLIER IN SUPPORTING LOW PRESSURE REMAINING FOCUSED IN CLOSER TO
SOUTHEAST NC. THE GLOBAL MODELS AND THE HIRES MODEL SUITE SUGGEST
THE INITIAL LOW CENTER DAMPENING OUT AND EVEN CYCLONICALLY LOOPING
AROUND A NEW AREA OF LOW PRESSURE DEVELOPING TO THE SOUTH ALONG
THE ATTENDANT FRONT OFF THE SOUTHEAST COASTLINE. OF THE GLOBAL
MODELS, THE 00Z UKMET FOCUSES ITS LOW PRESSURE EVOLUTION A BIT
FARTHER TO THE SOUTHWEST AND AWAY FROM THE MODEL CONSENSUS WHICH
EXTENDS OUT THROUGH 36 HOURS. MEANWHILE, THE 12Z GFS COLLECTIVELY
WITH ITS LOW CENTERS ENDS UP A BIT FARTHER EAST OF THIS CONSENSUS.
THE BETTER MODEL CLUSTERING THROUGH 36 HOURS IS WITH THE 00Z
CMC/ECMWF ALONG WITH THE 12Z ARW/ARW2 AND 12Z NAM-CONEST. THE 12Z
NMMB IS A NORTHERLY OUTLIER WITHIN THE HIRES MODEL SUITE.
AFTER 36 HOURS, AS LOW PRESSURE CONSOLIDATES OFF THE SOUTHERN
MID-ATLANTIC COASTLINE, THE 12Z GFS TAKES THE LOW CENTER NORTHWARD
AND TO THE EAST OF ALL OF THE AVAILABLE DETERMINISTIC GUIDANCE.
THE 12Z NAM AND 00Z UKMET END UP MUCH FARTHER WEST WITH A MORE
SIGNIFICANT IMPACT TO THE NORTHEAST AS THE LOW CENTER GETS PULLED
IN TOWARD THE COAST OR INLAND. THIS CLUSTER OF SOLUTIONS THAT
TRACKS FARTHER WEST IS HIGHLY TIED INTO THE UPSTREAM SHORTWAVE
TROUGHING THAT AMPLIFIES INTO THE OH/TN VALLEYS AND BECOMES
NEGATIVELY TILTED ACROSS THE CENTRAL/SOUTHERN APPALACHIANS LATER
SUNDAY AND INTO MONDAY. THIS RESULTS IN A BACKING OF THE LARGE
SCALE FLOW ACROSS THE NORTHEAST WHICH FORCES THE LOW TRACK FARTHER
WEST. THE 00Z CMC AND 00Z ECMWF SPLIT THE DIFFERENCE BETWEEN THE
TWO OUTLIER CAMPS. HOWEVER, THE ENSEMBLE SPREAD IS SIGNIFICANT,
AND IF ANYTHING FAVORS THE LOW CENTER TO STILL TRACK FARTHER
OFFSHORE. FOR NOW, GIVEN THE OVERALL TRENDS OF SEVERAL MODELS TO
TREND FARTHER WEST WITH THE LOW CENTER, A BLEND OF THE CMC AND
ECMWF WILL BE PREFERRED AFTER 36 HOURS WHICH WILL MINIMIZE SUPPORT
FOR THE NAM/UKMET AND GFS FOR THE TIME BEING.
..AMPLIFYING TROUGH ACROSS THE CENTRAL/EASTERN U.S
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 48 HOURS
00Z CMC/ECMWF BLEND...AFTER 48 HOURS
CONFIDENCE: AVERAGE...BECOMING BELOW AVERAGE AFTER 48 HOURS
A SHORTWAVE WILL DROP SOUTHEAST DOWN ACROSS THE INTERMOUNTAIN
REGION AND BEGIN TO AMPLIFY THROUGH SATURDAY. THIS ENERGY WILL
TRAVERSE THE PLAINS/MIDWEST THROUGH EARLY SUNDAY AND THEN BECOME
NEGATIVELY TILTED BY SUNDAY NIGHT AS IT CROSSES THE OH/TN VALLEYS.
SIGNIFICANT MODEL SPREAD EXISTS BY MONDAY AS THE ENERGY CROSSES
THE CENTRAL/SOUTHERN APPALACHIANS AND MID-ATLANTIC REGION, AS THE
00Z UKMET/CMC/ECMWF SOLUTIONS ARE SLOWER THAN THE 12Z NAM/GFS, AND
IN THE CASE OF THE UKMET, IT FAVORS A STRONGER CLOSED LOW
EVOLUTION ACROSS THE MID-ATLANTIC AT THE END OF THE PERIOD THAT
INTERACTS WITH THE LOW CENTER IMPACTING THE NORTHEAST. THERE IS
SOME SUPPORT FOR THE SLOWER CONSENSUS FROM THE 00Z ECENS MEAN AND
06Z GEFS MEAN, SO A BLEND TOWARD THE ECMWF AND CMC WILL BE
PREFERRED AFTER ABOUT 48 HOURS WITH THIS ENTIRE SYSTEM.
..CLOSED LOW DEVELOPMENT OFFSHORE SOUTHERN CALIFORNIA ON FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
THE MODELS MAINTAIN THE IDEA OF A CLOSED LOW DEVELOPING AND
EVOLVING OFFSHORE SOUTHERN CA WITH THE LOW DROPPING SOUTH TO THE
WEST OF THE BAJA PENINSULA THROUGH THE WEEKEND. THIS SYSTEM WILL
HAVE AN INTERACTION WITH T.S. RAYMOND OVER THE EASTERN TROPICAL
PACIFIC AS ITS ENERGY AND MOISTURE WILL BE PULLED NORTH TOWARD THE
BAJA PENINSULA THROUGH THE PERIOD. A GENERAL MODEL BLEND WILL BE
PREFERRED FOR NOW.
..UPPER TROUGH ARRIVING ACROSS THE PACIFIC NORTHWEST ON MON
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z UKMET/ECMWF
CONFIDENCE: AVERAGE
THE MODELS BRING A PROGRESSIVE SHORTWAVE TROUGH AND ASSOCIATED
SURFACE LOW IN TOWARD THE PACIFIC NORTHWEST ON MONDAY.. THE 12Z
NAM AND 12Z GFS ARE ON THE FASTER SIDE OF THE GUIDANCE, WITH THE
00Z CMC/ECMWF SOLUTIONS SLOWER. OVERALL, THE CMC IS A SLOW
OUTLIER. THE 00Z UKMET IS IN BETWEEN THE ECMWF AND THE NAM/GFS
SOLUTIONS. THE LATEST ENSEMBLE SUITES TEND TO FAVOR A SOLUTION A
LITTLE SLOWER THAN THE FASTER DETERMINISTIC CONSENSUS WHICH
SUGGESTS A SOLUTION TOWARD A BLEND OF THE ECMWF AND UKMET WOULD
SUFFICE FOR NOW.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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