906
FXUS10 KWNH 131847
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
245 PM EDT WED MAY 13 2020
VALID MAY 13/1200 UTC THRU MAY 17/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING FINAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...CLOSED LOW OVER ALBERTA TRACKING TO THE UPPER GREAT LAKES
THU...THEN ACROSS NORTHERN NEW ENGLAND FRI...
...SURFACE LOW MOVING FROM THE NORTH CENTRAL US TONIGHT INTO
NORTHERN NEW ENGLAND FRI...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM/12Z ECMWF BLEND
CONFIDENCE: AVERAGE
THE 12Z NAM/GFS ARE CLOSE TO THE CONSENSUS WITH THE SHORT WAVE
ENERGY SWINGING OUT OF SOUTHERN ALBERTA ACROSS THE UPPER GREAT
LAKES BY 15/12Z. AFTER THAT TIME, THE 12Z GFS BECOMING SLOWER THAN
THE CONSENSUS (AS IT HAS BEEN FOR THE PAST THREE MODEL CYCLES)
WITH THE SHORT WAVE CROSSING NORTHERN NEW ENGLAND AFTER 16/12Z. BY
CONTRAST, THE 12Z NAM MAINTAINS CONTINUITY WITH ITSELF AND THE
CONSENSUS WITH THE TIMING OF THE SHORT WAVE. THE 12Z CMC REMAIN
CLOSE TO THE CONSENSUS TIMING, BUT REMAINS FLAT WITH THE SHORT
WAVE AS IT CROSSES NORTHERN NEW ENGLAND. THE BIGGEST CHANGE WAS
WITH THE 12Z UKMET, WHICH SPED UP ITS SHORT WAVE TIMING, BECOMING
THE EASTERNMOST MEMBER OF THE ENSEMBLE GUIDANCE.
THE 12Z GFS ALSO REMAINS SLOWER WITH THE SURFACE WAVE AS IT EXITS
THE ME COAST AFTER 16/12Z, WITH THE REMAINDER OF THE GUIDANCE
FORMING A FAIRLY TIGHT CLUSTER WITH THE SURFACE LOW AS IT PASSES
SOUTH OF NOVA SCOTIA. GIVEN THE SLOWNESS OF THE GFS, AND THE
WEAKNESS OF THE 12Z CMC SHORT WAVE AND CHANGE IN THE 12Z UKMET,
FORECAST CONFIDENCE REMAINS AVERAGE THROUGH THIS PERIOD.
....CLOSED MID LEVEL LOW OFF THE PACIFIC NORTHWEST COAST
THU...MOVING TO THE NORTHERN PLAINS SAT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
BOTH THE 12Z NAM/GFS ARE CLOSE TO THE CONSENSUS TAKING THE CLOSED
MID LEVEL LOW OFF THE PACIFIC NORTHWEST COAST THU AND TRACKING IT
ACROSS THE NORTHERN ROCKIES BEFORE REACHING THE NORTHERN PLAINS BY
17/00Z. IN FACT, THERE IS GENERALLY GOOD CLUSTERING WITH THIS
FEATURE, SO A GENERAL MODEL BLEND IS PREFERRED WITH SLIGHTLY ABOVE
AVERAGE FORECAST CONFIDENCE.
..MID LEVEL TROUGH OVER NORTHERN MEXICO THU
MOVING INTO CENTRAL
TX SAT...
..SURFACE LOW OVER EASTERN NM/WEST TX FRI
CROSSING INTO CENTRAL
TX SAT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-12Z ECMWF MODEL BLEND
CONFIDENCE: AVERAGE
THE 12Z NAM/GFS ARE CLOSE TO THE MODEL CONSENSUS DEVELOPING A LONG
WAVE TROUGH OVER NORTHERN MEXICO THU...THEN TRACKING IT EASTWARD
ACROSS NM INTO CENTRAL TX SAT. WHILE THERE ARE SOME MINOR
DIFFERENCES IN THE PLACEMENT/STRENGTH OF THE MID LEVEL SYSTEM IN
CENTRAL TX, THERE IS A GOOD CLUSTERING HERE, AS IT THE SURFACE
SYSTEM. THE 12Z ECMWF NOW SEEMS TO BE TOO FAR NORTH WITH THE MID
LEVEL SYSTEM OVER THE RED RIVER VALLEY, WITH ENOUGH CHANGE TO
REMOVE IT FROM THE PREFERENCE. GIVEN THE CHANGE WITH THE 12Z
ECMWF, FORECAST AVERAGE HAS DROPPED TO AVERAGE.
..LOW PRESSURE DEVELOPING NEAR THE BAHAMAS FRI NIGHT INTO SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/12Z ECMWF/12Z GEFS MEAN/00Z ECMWF MEAN BLEND
CONFIDENCE: AVERAGE
THE 12Z GFS HAS BACKED OFF ON ITS WESTWARD DEPICTION OF THE
SURFACE WAVE CLOSER TO THE FL EAST COAST LATE FRI NIGHT, BEFORE
MOVING THE WAVE NORTH OF THE BAHAMAS SAT. THE EASTWARD MOVEMENT
BRINGS IT CLOSER TO THE 12Z GEFS MEAN/00Z ECMWF MEAN WITH THE
PLACEMENT OF THE SURFACE WAVE BY 17/00Z. THE 12Z ECMWF BROUGHT THE
SURFACE WAVE BACK TOWARD THE 12Z GFS, ENOUGH SO THAT IT WAS
INTRODUCED TO THE PREFERRED BLEND.
IN CONTRAST, THE 12Z NAM/12Z UKMET LOOK TOO FAR EAST WITH THE
SYSTEM FROM FRI NIGHT INTO SAT, WHILE THE 12Z CMC HAS RETURNED TO
A MORE WESTERN SOLUTION, AS ITS MID LEVEL SYSTEM TRIES TO TAKE OF
A NEGATIVE TILT. SINCE THE 12Z ECMWF HAS COME BACK CLOSER TO THE
THE 12Z GFS/ENSEMBLE CLUSTER, FORECAST CONFIDENCE HAS INCREASED,
BUT STILL REMAINS AVERAGE WITH THIS SYSTEM.
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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