657
FXUS10 KWNH 250642
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 AM EDT MON MAY 25 2020
VALID MAY 25/0000 UTC THRU MAY 28/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
WEAKENING SHORTWAVE CROSSING NORTHERN NEW ENGLAND ON MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A MID-LEVEL TROUGH CURRENTLY WEAKENING OVER THE GREAT LAKES REGION
WILL DAMPEN FURTHER ON MONDAY WHILE SHEARING ACROSS NORTHERN NEW
ENGLAND. THE MODELS ARE IN GOOD AGREEMENT WITH THE DETAILS OF
THIS, SO A GENERAL MODEL BLEND WILL BE PREFERRED.
SHORTWAVE OVER THE NORTHERN PLAINS THROUGH MONDAY
RELOADING NORTHERN STREAM TROUGH OVER NORTHERN PLAINS BY WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
A CLOSED LOW INITIALLY OVER WYOMING AND EASTERN MONTANA IS
FORECAST TO EVOLVE INTO AN OPEN WAVE AS IT REACHES THE WESTERN
DAKOTAS BY MONDAY AFTERNOON. BY TUESDAY THIS DISTURBANCE SHOULD
BECOME ABSORBED BY THE WESTERLIES ACROSS SOUTHERN CANADA. THE
GUIDANCE IS IN GOOD AGREEMENT WITH THE DETAILS OF THIS EXITING
SYSTEM. HOWEVER, BY LATER TUESDAY AND INTO WEDNESDAY, THE MODELS
SUPPORT AMPLIFICATION OF A NEW NORTHERN STREAM TROUGH OVER
SOUTHERN CANADA AND THE NORTHERN PLAINS. THIS WILL DRIVE SURFACE
LOW PRESSURE ACROSS SOUTHERN CANADA WITH A TRAILING COLD FRONT
THAT WILL BE CROSSING THE NORTHERN PLAINS. THE MODELS OVERALL ARE
FAIRLY WELL CLUSTERED WITH THE HEIGHT FALL EVOLUTION OF THIS NEXT
TROUGH, ALTHOUGH THE 00Z CMC LATE IN THE PERIOD EDGES TOWARD THE
SLOWER AND DEEPER SIDE OF THE GUIDANCE WITH THE TROUGH. WILL
PREFER A NON-CMC BLEND AT THIS POINT, AND THIS WILL ALSO ACT AS A
COMPROMISE WITH THE SURFACE LOW EVOLUTION TO RESOLVE SOME SPATIAL
SPREAD SEEN WITH THE WAVE ACTIVITY AT THE END OF THE PERIOD OVER
SOUTH-CENTRAL CANADA.
SYNOPTIC SCALE TROUGH OVER THE WEST EVOLVING INTO CLOSED LOW OVER
SOUTHERN PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS/ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
A SYNOPTIC SCALE UPPER TROUGH INITIALLY OVER THE INTERMOUNTAIN
WEST WILL DROP EAST-SOUTHEAST OVER THE CENTRAL AND SOUTHERN PLAINS
OVER THE NEXT COUPLE OF DAYS, WITH A CUT-OFF UPPER LOW EXPECTED TO
SET UP OVER FAR NORTHERN TX BY LATE TUESDAY. THIS UPPER LOW SHOULD
THEN DRIFT VERY SLOWLY EASTWARD THROUGH NORTHEAST TEXAS BY EARLY
THURSDAY. MODEL MASS FIELD SPREAD IS MINIMAL THROUGH EARLY
TUESDAY, BUT BY LATE TUESDAY THROUGH THE END OF THE PERIOD, THE
00Z UKMET ENDS UP ON THE SOUTH SIDE OF THE GUIDANCE WITH THE
POSITION OF THE UPPER LOW. THE 00Z CMC IS ACTUALLY A TAD TO THE
NORTH, WITH THE 00Z NAM/GFS/ECMWF SOLUTIONS CLUSTERED IN BETWEEN
BUT WELL SUPPORTED BY THE 00Z GEFS MEAN AND YESTERDAY'S 12Z ECENS
MEAN. AT THE SURFACE, MULTIPLE WAVES OF LOW PRESSURE WILL BE
LIFTING NORTH ALONG A FRONT ADVANCING EAST ACROSS THE PLAINS.
GENERALLY THE BETTER MODEL CLUSTERING AND ENSEMBLE SUPPORT RESIDES
WITH THE GFS AND ECMWF. SO, BASED ON THE LATEST TRENDS AND
CLUSTERING OF SOLUTIONS, A BLEND OF THESE SOLUTIONS WILL BE
PREFERRED AT THE SURFACE AND ALOFT WITH THE MASS FIELDS.
MID-LEVEL TROUGH AND WEAK SURFACE LOWS IMPACTING FLORIDA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z NAM/GFS/ECMWF
CONFIDENCE: AVERAGE
AN UPPER LEVEL RIDGE WILL BE BUILDING ACROSS THE SOUTHEAST U.S.
EARLY THIS WEEK AND GRADUALLY OUT ACROSS THE WESTERN ATLANTIC BY
MIDWEEK. SOUTH OF THE UPPER RIDGE WILL BE A LOW TO MID-LEVEL
TROUGH AXIS WHICH IS EXPECTED TO LIFT NORTHWARD THROUGH THE
EASTERN GULF OF MEXICO AND THE FL PENINSULA GOING THROUGH TUESDAY.
BY WEDNESDAY, THIS ENERGY WILL BE ADVANCING NORTH INTO THE
SOUTHEAST U.S. WITHIN DEEP LAYER SOUTHERLY FLOW SITUATED BETWEEN
THE DEEP UPPER LOW OVER NORTHEAST TX AND THE BUILDING RIDGE OVER
THE WESTERN ATLANTIC. MULTIPLE WAVES OF LOW PRESSURE, POSSIBLY
CONVECTIVELY INDUCED, ARE EXPECTED TO EVOLVE WITH THIS SYSTEM WITH
ONE LOW LIFTING NORTH ACROSS THE EASTERN GULF OF MEXICO, AND
ANOTHER FORMING NEAR THE EAST COAST OF FL.
GENERALLY THE GUIDANCE IS MORE SUBTLE WITH THE WAVE OVER THE
EASTERN GULF OF MEXICO VERSUS THE WAVE ALONG THE FL EAST COAST, AS
THE 00Z NAM/GFS/ECMWF SOLUTIONS ALL SUGGESTING A RELATIVELY
WELL-DEFINED LOW IN THE VICINITY OF MELBOURNE, FL BY 12Z TUESDAY.
THE 00Z CMC AND 00Z UKMET SUGGEST THE WAVE OVER THE EASTERN GULF
OF MEXICO WILL BE MORE DEFINED BY COMPARISON. THE 00Z UKMET STILL
MAY BE A TAD TOO SUPPRESSED WITH ITS MID-LEVEL TROUGH AND
ASSOCIATED WAVE ACTIVITY, BUT THE UKMET DID TREND FARTHER NORTH
THIS CYCLE AND TOWARD THE MAJORITY CONSENSUS. WILL CONTINUE TO
FAVOR A BLEND OF THE NAM, GFS AND ECMWF FOR THE TIME BEING GIVEN
OVERALL BETTER 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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page