499
FXUS10 KWNH 131639
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1138 AM EST WED NOV 13 2019
VALID NOV 13/1200 UTC THRU NOV 17/0000 UTC
..SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..SHORTWAVE CROSSING THE PLAINS/MIDWEST
..CLOSED LOW DEVELOPMENT OVER THE SOUTHEAST
..CYCLOGENESIS OFF THE SOUTHEAST COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 36 HOURS
12Z GFS...AFTER 36 HOURS
CONFIDENCE: ABOVE AVERAGE...BECOMING BELOW AVERAGE AFTER 36 HOURS
A SHORTWAVE WHICH IS CURRENTLY CROSSING PORTIONS OF THE PLAINS AND
MIDWEST WILL BEGIN TO SEPARATE OUT FROM THE WESTERLIES AND DIG
DOWN ACROSS THE LOWER MS AND TN VALLEYS ON THURSDAY. AS THIS
ENERGY DROPS SOUTHEAST ACROSS THE GULF COAST STATES, IT SHOULD
INTERACT WITH AND CAPTURE ENERGY ASSOCIATED WITH AN EJECTING
SOUTHERN STREAM CLOSED LOW CROSSING FROM MEXICO THROUGH SOUTH
TEXAS AND THE WESTERN GULF OF MEXICO. THE RESULT OF THIS
INTERACTION WILL ULTIMATELY BE A CLOSED LOW OVER THE SOUTHEAST BY
FRIDAY, WITH COASTAL CYCLOGENESIS TAKING PLACE JUST SOUTHEAST OF
THE CAROLINAS.
THE 12Z NAM AGAIN BECOMES STRONGER THAN THE GLOBAL MODELS WITH THE
CLOSED LOW EVOLUTION ACROSS THE SOUTHEAST AND THEN OFFSHORE GOING
THROUGH FRIDAY AND SATURDAY. THE NAM IS AN OUTLIER SOLUTION WITH A
LEAD SURFACE LOW THAT DEVELOPS NEAR THE NC OUTER BANKS BY EARLY
FRIDAY WHICH THEN LIFTS NORTHEAST UP ALONG A FRONTAL ZONE. THE
ENTIRE GLOBAL MODEL SUITE FOCUSES THE MAIN AREA OF CYCLOGENESIS
FARTHER SOUTH AND OFFSHORE OF SC BY LATE FRIDAY, ALTHOUGH
EVENTUALLY THE NAM DOES DEVELOP A NEW AREA OF LOW PRESSURE IN THE
AREA FRIDAY NIGHT THROUGH SATURDAY, WITH ALL OF THE MODELS AT
LEAST AGREEING ON THERE BEING A RATHER STRONG AREA OF LOW PRESSURE
SOUTHEAST OF THE CAROLINAS ON SATURDAY. REGARDING THE GLOBAL
MODELS, THE 00Z ECMWF APPEARS TO BE TOO SLOW WITH ITS HEIGHT FALL
PROGRESSION, AND THE 00Z CMC APPEARS TO BE TOO WEAK. THE 12Z GFS
IS VERY CLOSE TO THE MULTI-MODEL CONSENSUS, WITH THE 00Z UKMET
JUST A LITTLE EAST OF THE GFS WITH THE SURFACE LOW EVOLUTION. THE
ENSEMBLE MEANS ARE SPLIT WITH TIMING AS THE ECENS MEAN IS ON THE
SLOW SIDE OF THE GUIDANCE AND THE GEFS MEAN FASTER, ALTHOUGH THE
LATEST GFS IS NOT AS PROGRESSIVE AS THE GEFS MEAN. BASED ON THE
LATEST MODEL CLUSTERING AND ENSEMBLE SPREAD, A GENERAL MODEL BLEND
WILL BE PREFERRED THROUGH 36 HOURS, FOLLOWED BY A SOLUTION TOWARD
THE GFS THEREAFTER, ALTHOUGH CONFIDENCE IS LIMITED IN TIME GIVEN
THE RATHER BROAD SPREAD SEEN WITH THE SURFACE LOW EVOLUTION LATE
IN THE PERIOD.
..STRONG NORTHERN STREAM TROUGH BRUSHING THE NORTHEAST BY FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 60 HOURS
NON-NAM BLEND...AFTER 60 HOURS
CONFIDENCE: ABOVE AVERAGE
THE MODELS PLACE A STRONG NORTHERN STREAM CLOSED LOW DOWN OVER
PORTIONS OF QUEBEC BY FRIDAY, WITH HEIGHT FALLS BRUSHING PORTIONS
OF THE NORTHEAST. THE MODELS SHOW GOOD OVERALL AGREEMENT WITH THIS
SYSTEM THROUGH 60 HOURS, WITH THE 12Z NAM THEN BECOMING A LITTLE
SLOWER/DEEPER THAN THE GLOBAL MODELS AS THE ENERGY BEGINS TO PULL
AWAY ON SATURDAY THROUGH THE CANADIAN MARITIMES. WILL PREFER A
GENERAL MODEL BLEND THROUGH 60 HOURS, AND A NON-NAM BLEND
THEREAFTER.
..MID-LEVEL SHORTWAVES APPROACHING THE WEST COAST ON THURS
..ENERGY DIGGING ACROSS THE INTERMOUNTAIN WEST FRI/SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z NAM/00Z CMC AND 00Z ECMWF
CONFIDENCE: AVERAGE
A RELATIVELY WEAK MID-LEVEL SHORTWAVE IS EXPECTED TO APPROACH THE
WEST COAST EARLY ON THURSDAY WHILE A SECOND SHORTWAVE FARTHER
NORTH AIMS TOWARD VANCOUVER ISLAND AND SOUTHERN BRITISH COLUMBIA
BY EARLY FRIDAY. THE INITIAL SHORTWAVE SHOULD DAMPEN OUT, BUT THE
SECOND SHORTWAVE FARTHER NORTH IS EXPECTED TO DROP SOUTHEAST DOWN
ACROSS THE INTERMOUNTAIN WEST AND BEGIN TO AMPLIFY THROUGH
SATURDAY. THE 00Z UKMET BECOMES THE FASTEST SOLUTION WITH THE
AMPLIFYING TROUGH, WITH THE 12Z GFS THE SLOWEST. THE 12Z NAM, 00Z
ECMWF AND 00Z CMC SPLIT THE DIFFERENCE BETWEEN CAMPS AND ACTUALLY
CLUSTER TOGETHER RATHER WELL, SO A BLEND OF THESE SOLUTIONS WILL
BE PREFERRED.
..CLOSED LOW DEVELOPMENT OFFSHORE SOUTHERN CALIFORNIA ON FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: ABOVE AVERAGE
ADDITIONAL SHORTWAVE ENERGY APPROACHING CALIFORNIA LATE THURSDAY
WILL BREAK AWAY AND DIG SOUTHEAST TO OFFSHORE SOUTHERN CALIFORNIA
ON FRIDAY, WITH THE GUIDANCE SUPPORTING A WEAK CLOSED LOW
EVOLUTION THAT DROPS DOWN TO WEST OF THE BAJA PENINSULA BY
SATURDAY. THE 12Z NAM ENDS UP ON THE SOUTH SIDE OF THE MODEL SUITE
BY THE END OF THE PERIOD. THE ENSEMBLE MEANS FAVOR THE NON-NAM
GUIDANCE, SO A NON-NAM BLEND WILL BE PREFERRED.
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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