068
FXUS10 KWNH 230420
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1219 AM EDT SAT MAY 23 2020
VALID MAY 23/0000 UTC THRU MAY 26/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..CUT-OFF LOW IMPACTING THE OH VALLEY AND NORTHERN MID-ATLANTIC
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE DETAILS OF THE
CUT-OFF UPPER LOW CURRENTLY OVER THE UPPER OH VALLEY WHICH WILL
ADVANCE EAST ACROSS THE NORTHERN MID-ATLANTIC REGION ON SATURDAY
AND THEN MOVE OFFSHORE. A GENERAL MODEL BLEND WILL BE PREFERRED
WITH THIS SYSTEM.
..DEEP UPPER TROUGH/CLOSED LOW RELOADING OVER THE WESTERN U.S
..EJECTING OUT OVER THE PLAINS BY TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 48 HOURS
18Z GEFS MEAN/12Z ECENS MEAN BLEND...AFTER 48 HOURS
CONFIDENCE: AVERAGE...BECOMING BELOW AVERAGE AFTER 48 HOURS
THE LATEST GUIDANCE SHOWS VERY GOOD AGREEMENT IN BRINGING A NEW
LARGE SCALE UPPER TROUGH AND ASSOCIATED CLOSED LOW IN ACROSS THE
INTERMOUNTAIN WEST THIS WEEKEND. BY EARLY NEXT MONDAY, THE
CONSENSUS OF GUIDANCE SUPPORTS A DEEP TROUGH EDGING TOWARD THE
PLAINS WITH ONE CLOSED LOW CENTER EXITING THE NORTHERN ROCKIES AND
CROSSING THE NORTHERN HIGH PLAINS BY THEN. MEANWHILE, A SECOND
CLOSED LOW WILL BE ATTEMPTING TO FOCUS OVER THE CENTRAL ROCKIES BY
THEN, AND BY TUESDAY, THE GUIDANCE IS IN REASONABLY GOOD AGREEMENT
ON THE IDEA OF THIS CLOSED LOW BECOMING BETTER DEFINED OUT ACROSS
THE SOUTHERN HIGH PLAINS. THE MODELS GENERALLY SHOW GOOD AGREEMENT
WITH THEIR MASS FIELDS THROUGH 48 HOURS, BUT THEREAFTER THE 12Z
UKMET IS SEEN AS FOCUSING MORE OF ITS CLOSED LOW ENERGY FARTHER
NORTH OVER THE CENTRAL PLAINS VERSUS THE SOUTHERN PLAINS. THE 00Z
NAM/GFS AND REMAINING 12Z NON-NCEP MODELS ALL HAVE AN UPPER LOW
THAT IS OVER IN VICINITY OF THE TX PANHANDLE BY TUESDAY. THIS WILL
ALSO RESULT IN A CORRESPONDING SURFACE LOW, AND WITH THIS FEATURE
THERE IS GREATER SPREAD. THE 12Z CMC HAS A WEAKER AND NORTHERLY
TRACKING LOW CENTER UP OVER NORTHERN MO AT THE END OF THE PERIOD
VERSUS THE 00Z NAM WHICH IS STRONGER AND HAS THE LOW DOWN OVER
CENTRAL OK. THE 00Z GFS AND 12Z UKMET HAVE THE LOW NEAR THE
SOUTHEAST KS/NORTHEAST OK BORDER, AND THE 12Z ECMWF HAS NO SURFACE
LOW AT ALL. THE 18Z GEFS MEAN AND 12Z ECENS MEAN BOTH HAVE A
WELL-DEFINED FRONT ACROSS THE PLAINS AND STRETCHING UP TOWARD THE
UPPER MIDWEST BY THE END OF THE PERIOD, BUT DO NOT NECESSARILY
SUGGEST A WELL-DEFINED LOW AT THIS POINT, AND UPON INSPECTION OF
INDIVIDUAL MEMBERS, THERE IS SIGNIFICANT SPREAD WITH THE DETAILS
OF SURFACE WAVE ACTIVITY ALONG THE FRONT OVER THE CENTRAL AND
SOUTHERN PLAINS REGION FROM MONDAY INTO TUESDAY. A GENERAL MODEL
BLEND SHOULD GENERALLY SUFFICE WITH THIS ENTIRE MASS FIELD
EVOLUTION THROUGH 48 HOURS, BUT THEREAFTER AS THE DEEP
TROUGH/CLOSED LOW EJECTS OUT ACROSS THE PLAINS, A BLEND OF THE
LATEST GEFS MEAN AND ECENS MEAN WILL BE PREFERRED GIVEN THE LARGE
SPREAD IN THE DETAILS OF SURFACE LOW PRESSURE. FORTUNATELY, THERE
IS REASONABLY GOOD AGREEMENT WITH THE DETAILS OF THE ENERGY ALOFT,
OUTSIDE THE AFOREMENTIONED UKMET SOLUTION.
..SHORTWAVE/CLOSED LOW CROSSING THE MIDWEST THROUGH SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-UKMET BLEND
CONFIDENCE: ABOVE AVERAGE
THE LATEST GOES-WV SATELLITE IMAGERY SHOWS A VERY WELL-DEFINED
CLOSED LOW OVER FAR SOUTHEAST NE WHICH WILL BE ADVANCING NORTHEAST
ACROSS THE UPPER MIDWEST THROUGH SATURDAY AND THEN GRADUALLY
WEAKENING OVER THE GREAT LAKES REGION ON SUNDAY AS IT ATTEMPTS TO
CREST THE DEEP LAYER RIDGE FORMING AND NOSING NORTHWARD BY THEN
OVER THE OH/TN VALLEYS AND SOUTHEAST. OVERALL, THE GUIDANCE IS IN
GOOD AGREEMENT WITH THIS SYSTEM, BUT THE 12Z UKMET AFTER ABOUT 36
HOURS HANGS ONTO A STRONGER TROUGH THAT EXITS THE GREAT LAKES AND
MOVES INTO PORTIONS OF NORTHERN NEW ENGLAND BY EARLY MONDAY. GIVEN
GOOD CLUSTERING IN THE GUIDANCE OTHERWISE, A NON-UKMET BLEND WILL
BE PREFERRED.
...SHORTWAVE LIFTING NORTHEAST ACROSS THE SOUTHERN PLAINS
SUNDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 18Z GEFS MEAN/12Z ECENS MEAN BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE
AS THE DEEP TROUGH AND ASSOCIATED CLOSED LOW EVOLVES ACROSS THE
WEST THIS WEEKEND AND SLOWLY ENCROACHES ON THE HIGH PLAINS, THERE
WILL BE A SHORTWAVE TROUGH ROUNDING THE BASE OF IT AND LIFTING
NORTHEAST ACROSS THE SOUTHERN PLAINS ON SUNDAY. THE 00Z NAM/GFS
SOLUTIONS ARE BIT STRONGER WITH THE ENERGY LIFTING NORTHEAST AND
EVEN SUGGEST THE POTENTIAL FOR A MORE DISCREET MID-LEVEL LOW
CENTER DEVELOPING OVER CENTRAL TX BY SUNDAY NIGHT. THE NON-NCEP
SOLUTIONS BY COMPARISON ARE ALL A TAD WEAKER. A BLEND OF THE
ENSEMBLE MEANS WILL BE PREFERRED FOR THE TIME BEING AS A
COMPROMISE, BUT WHICH ALSO DO HAVE REASONABLY GOOD AGREEMENT WITH
EACH OTHER IN BEING NOT QUITE AS STRONG AS THE NAM/GFS CAMP.
CONFIDENCE IS A TAD LIMITED.
..MID-LEVEL TROUGH IMPACTING SOUTHERN FL MONDAY AND TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z NAM/GFS AND 12Z ECMWF
CONFIDENCE: BELOW AVERAGE
AS A STRONG SUBTROPICAL RIDGE BUILDS OVER THE SOUTHEAST AND THE
MID-ATLANTIC REGION SUNDAY AND MONDAY, THERE WILL BE A MID-LEVEL
TROUGH AXIS LIFTING NORTH FROM NEAR THE YUCATAN PENINSULA AND
WESTERN CARIBBEAN SEA INTO THE SOUTHERN GULF OF MEXICO. THIS
ENERGY IS EXPECTED TO ELONGATE AND CROSS AREAS OF SOUTHERN FL BY
LATE MONDAY AND THROUGH TUESDAY. THE 00Z NAM/GFS AND 12Z ECMWF ARE
ALL FARTHER NORTH WITH THE TROUGH AXIS VERSUS THE 12Z CMC AND 12Z
UKMET. THERE HAS BEEN A MULTI-MODEL TREND TO FOCUS A STRONGER
MID-LEVEL TROUGH A BIT FARTHER NORTH OVER THE SOUTHEAST GULF OF
MEXICO AND SOUTHERN FL FOR MONDAY AND TUESDAY, WITH THE NAM/GFS
AND ECMWF ALL TRENDING IN THAT DIRECTION, SO WILL FAVOR A BLEND OF
THOSE SOLUTIONS AT THIS TIME WITH THE MASS FIELD DETAILS.
CONFIDENCE IS LIMITED THOUGH FOR THE TIME BEING IN THE DETAILS OF
THIS EVOLUTION SINCE THERE IS STILL MEANINGFUL DETERMINISTIC MODEL
SPREAD.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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