999
FXUS10 KWNH 151640
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1240 PM EDT SUN MAR 15 2020
VALID MAR 15/1200 UTC THRU MAR 19/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP UPPER TROUGH/CLOSED LOW IMPACTING THE WEST COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS, 00Z ECMWF, 00Z UKMET
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
AS A DEEP UPPER TROUGH AND EMBEDDED CLOSED LOW ALONG THE WEST
COAST SETTLES SOUTH OVER THE NEXT FEW DAYS, GOOD MODEL AGREEMENT
EXISTS UNTIL ABOUT TUESDAY EVENING. A TREND IN THE ENSEMBLES HAS
BEEN NOTED TO SHIFT THE UPPER TROUGH/CLOSED LOW FASTER TO THE EAST
INTO THE SOUTHWESTERN U.S. OVER THE PAST 3 12/00Z CYCLES VALID ON
TUESDAY. HOWEVER, THE 12Z NAM IS THE FASTEST TO PROGRESS THE LOW
EASTWARD, AND DESPITE THE TREND, APPEARS TO BE AN OUTLIER AT THE
MOMENT. THE 00Z CMC IS ALSO FASTER TO TAKE THE LOW INLAND AND DOES
NOT EXHIBIT THE DOUBLE BARREL APPEARANCE SEEN IN THE REMAINING
DETERMINISTIC GUIDANCE WEDNESDAY MORNING. THE RESULT IN THE 00Z
CMC IS A FASTER PROGRESSION WITH THE BASE OF THE MID-LEVEL TROUGH
INTO ARIZONA/NEW MEXICO BY WEDNESDAY EVENING.
THE ENSEMBLE MEANS SUPPORT A MIDDLE GROUND BETWEEN THE SOMEWHAT
FASTER 12Z GFS/00Z UKMET AND SLOWER 00Z ECMWF. THE PREFERENCE WILL
LEAN TOWARD THIS MIDDLE GROUND BUT WILL BE SUBJECT TO CHANGE
PENDING THE 12Z ECMWF/UKMET/CMC.
..TROUGH CROSSING THE UPPER MIDWEST/GREAT LAKES BY TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE 00Z UKMET AND 12Z GFS WERE NOTED TO BE SLIGHTLY FASTER WITH
THE UPPER TROUGH PROGRESSION AS IT CROSSES THE GREAT LAKES INTO
SOUTHERN ONTARIO. THE 12Z NAM WAS SLIGHTLY SLOWER WITH THE
ENSEMBLE MEANS IN THE MIDDLE OF THE SPREAD. OVERALL, TIMING
DIFFERENCES ARE MINOR WITH POTENTIAL FOR FUTURE CYCLES TO ADJUST A
LITTLE FASTER OR SLOWER. THE PREFERENCE IS TO BE IN THE MIDDLE
WHICH IS BEST REPRESENTED BY A GENERAL MODEL BLEND AT THS TIME.
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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