359
FXUS10 KWNH 240710
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
309 AM EDT SUN MAY 24 2020
VALID MAY 24/0000 UTC THRU MAY 27/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SHORTWAVE TROUGH CROSSING THE GREAT LAKES THROUGH SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A RATHER COMPACT MID TO UPPER-LEVEL LOW CENTER CROSSING THE
MIDWEST THIS EVENING WILL BE ADVANCING ACROSS THE GREAT LAKES
REGION ON SUNDAY AND WEAKENING WITH TIME AS IT TRACKS OVER THE
TOP OF A STRENGTHENING DEEP LAYER RIDGE OVER THE SOUTHEAST U.S. ON
MONDAY, A WEAK REMNANT OF THIS ENERGY WILL CROSS THROUGH NORTHERN
NEW ENGLAND. THE MODELS ARE IN GOOD AGREEMENT WITH THIS SYSTEM,
AND SO A GENERAL MODEL BLEND WILL BE PREFERRED.
DEEP UPPER TROUGH CROSSING THE INTERMOUNTAIN WEST TO THE PLAINS
LEAD SHORTWAVES CROSSING THE SOUTHERN PLAINS SUNDAY/MONDAY
CLOSED LOW FORMATION OVER THE SOUTHERN PLAINS BY TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...UPPER TROUGH EVOLUTION
00Z NAM/UKMET/ECMWF BLEND...SURFACE LOW EVOLUTION
CONFIDENCE: AVERAGE
THE LATEST GUIDANCE SHOWS VERY GOOD AGREEMENT IN BRINGING A NEW
LARGE SCALE UPPER TROUGH AND ASSOCIATED CLOSED LOW IN ACROSS THE
INTERMOUNTAIN WEST THROUGH THE WEEKEND. BY MONDAY, THE MODELS
SUPPORT THIS DEEP TROUGH EDGING TOWARD THE PLAINS WITH ONE CLOSED
LOW CENTER EXITING THE NORTHERN ROCKIES AND CROSSING THE NORTHERN
HIGH PLAINS. MEANWHILE, A SECOND CLOSED LOW WILL BE ATTEMPTING TO
FOCUS OVER THE CENTRAL ROCKIES, AND BY TUESDAY THE GUIDANCE IS IN
REASONABLY GOOD AGREEMENT ON THE IDEA OF A NEW CLOSED LOW BECOMING
WELL-DEFINED OVER THE SOUTHERN PLAINS.
LEADING UP TO THIS CLOSED LOW EVOLUTION OVER THE SOUTHERN PLAINS,
THERE WILL BE A PAIR OF SHORTWAVE TROUGHS, ONE ON SUNDAY AND ONE
ON MONDAY, THAT WILL ROUND THE BASE OF THE LARGER SCALE TROUGH AND
LIFT NORTHEAST ACROSS THE SOUTHERN PLAINS. THE FIRST SHORTWAVE IS
EXPECTED TO EVOLVE OUT OF THE MCS ACTIVITY CURRENTLY IMPACTING
AREAS SOUTH-CENTRAL TX AND THE MIDDLE RIO GRANDE VALLEY. THE
SECOND AND MORE DOMINANT SHORTWAVE IS CURRENTLY SHOWING UP VERY
DISTINCTLY ACROSS THE SOUTHWEST U.S. AND NORTHWEST MEXICO IN
GOES-WV SATELLITE IMAGERY, AND IS MOVING STEADILY OFF TO THE EAST.
THE 00Z NAM AND 00Z GFS ARE JUST SLIGHTLY STRONGER THAN THE 00Z
NON-NCEP MODELS WITH THE FIRST SHORTWAVE, BUT THE MASS FIELDS ARE
REALLY QUITE MODEST. THIS ENERGY WILL LIFT NORTHEAST THROUGH
SUNDAY NIGHT TOWARD THE LOWER MS VALLEY AS THE SECOND UPSTREAM
SHORTWAVE TROUGH ARRIVES AND ULTIMATELY FOSTERS THE UPPER LOW
DEVELOPMENT OVER THE SOUTHERN PLAINS BY TUESDAY.
WITH THE SECOND SHORTWAVE, THE NAM AND GFS ARE ALSO A TAD STRONGER
THAN THE NON-NCEP MODELS, WITH THE GFS ALSO BEING A TAD ON THE
FASTER SIDE OF THE GUIDANCE. HOWEVER, BY THE END OF THE PERIOD,
THE GUIDANCE DOES CLUSTER BETTER NOW WITH THE PLACEMENT OF THE
UPPER LOW OVER CENTRAL TX, WITH ONLY THE NAM APPEARING TO BE
PERHAPS A LITTLE TOO SLOW WITH ITS EASTWARD EJECTION OF IT. THE
00Z GEFS MEAN ALSO SUPPORTS THIS PLACEMENT, WITH THE FORMER 12Z
ECENS MEAN JUST A TAD OFF TO THE EAST. THERE IS BETTER AGREEMENT
TOO WITH THE SURFACE LOW CENTER EVOLUTION, WHICH NOW IS CONVERGING
ON THE IDEA OF A STRONGER LOW OVER SOUTHEAST KS EARLY TUESDAY, AND
THEN A MORE MODEST WAVE OVER EAST TX BY EARLY WEDNESDAY. THE GFS
LOOKS TOO WEAK NOW WITH ITS SOLUTION OVER KS, WITH THE CMC
PROBABLY TOO FAR TO THE WEST, BUT THE NAM/ECMWF/UKMET SOLUTIONS
ARE BETTER CLUSTERED OVER SOUTHEAST KS, AND THESE SOLUTIONS ALSO
ALL FAVOR THE MODEST WAVE OVER EAST TEXAS. BY THE END OF THE
PERIOD, THE GFS STILL LOOKS LIKE IT IS TOO WRAPPED UP AND TOO FAR
WEST WITH ITS TX LOW CENTER, AND THE CMC TOO FAR NORTH WITH A WAVE
OVER EASTERN OK. BASED ON THE LATEST MODEL TRENDS AND CLUSTERING,
A GENERAL MODEL BLEND WILL BE PREFERRED WITH THE BROADER UPPER
TROUGH, SHORTWAVES AND CLOSED LOW EVOLUTION. HOWEVER, WITH THE
SURFACE WAVES, A BLEND OF THE NAM, UKMET AND ECMWF WILL BE
PREFERRED.
MID-LEVEL TROUGH IMPACTING FLORIDA EARLY IN THE WEEK
WEAK SURFACE LOW OVER EAST-CENTRAL GULF OF MEXICO
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z NAM/GFS/ECMWF BLEND...FOR THE MID-LEVEL TROUGH
00Z NAM AND 12Z/00Z ECMWF BLEND...FOR THE GULF LOW
CONFIDENCE: AVERAGE
AS A STRONG SUBTROPICAL RIDGE BUILDS OVER THE SOUTHEAST AND THE
MID-ATLANTIC REGION GOING INTO THE BEGINNING OF THE WEEK, THERE
WILL BE A MID-LEVEL TROUGH AXIS LIFTING NORTH FROM THE YUCATAN
PENINSULA AND WESTERN CARIBBEAN SEA TO THE SOUTHERN GULF OF
MEXICO. THIS ENERGY IS EXPECTED TO ELONGATE AND CROSS AREAS OF
SOUTHERN FLORIDA BY LATE MONDAY AND INTO TUESDAY. THERE IS ALSO
GROWING SUPPORT FOR A WEAK AREA OF LOW PRESSURE TO FORM ALONG AN
INVERTED SURFACE TROUGH AS WELL, WITH THE 00Z NAM, 12Z ECMWF AND A
LARGE NUMBER OF EUROPEAN AND CANADIAN ENSEMBLE MEMBERS SUGGESTING
SURFACE LOW DEVELOPMENT. THE 00Z HREF MODEL SUITE ALSO SUPPORTS
THIS AS WELL. WITH RESPECT TO THE MID-LEVEL TROUGH, THE 00Z UKMET
AGAIN REMAINS MORE SUPPRESSED WITH IT AND THIS IS A RESULT OF THE
UKMET BEING STRONGER WITH ITS SUBTROPICAL RIDGE TO THE NORTH OVER
THE SOUTHEAST U.S. THE 00Z CMC IS ALSO SOMEWHAT SUPPRESSED TOO,
BUT NOT TO THE SAME EXTENT. THE 00Z ECMWF CAME IN STILL FARTHER
NORTH WITH ITS MID-LEVEL TROUGH EVOLUTION, BUT IT DID TREND A TAD
FARTHER SOUTH WITH ITS GULF LOW CENTER, AND ALSO IT HAS A MUCH
SHARPER EASTWARD EXTENDING TROUGH ACROSS THE FL PENINSULA ALONG
WITH EVIDENCE OF A SECOND LOW CENTER (POSSIBLY FROM CONVECTIVE
FEEDBACK) NEAR THE EAST COAST OF FL FROM 48 TO 72 HOURS. THE UKMET
ALSO EVENTUALLY SUGGESTS A LOW CENTER OFF THE EAST COAST OF FL,
EXCEPT IT IS FARTHER SOUTH. THE MASS FIELD PREFERENCES ARE A
LITTLE COMPLICATED, BUT A BLEND OF THE NAM, GFS AND ECMWF WILL BE
PREFERRED FOR THE MID-LEVEL TROUGH EVOLUTION, BUT FOR THE WEAK
SURFACE LOW FEATURE OVER THE GULF OF MEXICO, A BLEND OF THE 00Z
NAM AND THE LAST TWO RUNS OF THE ECMWF (00Z/12Z) WILL BE PREFERRED
WHICH WOULD HELP TO MITIGATE THE NEW ECMWF POSSIBLY BEING A BIT
TOO AGGRESSIVE WITH ITS SURFACE TROUGH OVER FL ALONG WITH ITS LOW
CENTER NEAR THE EAST COAST OF FL.
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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