571
FXUS10 KWNH 140448
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1148 PM EST FRI DEC 13 2019
VALID DEC 14/0000 UTC THRU DEC 17/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES AND FORECAST
CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEPENING SURFACE LOW OVER THE NORTHEAST TODAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
ONLY MINOR TIMING AND STRENGTH DIFFERENCES WERE SEEN WITH THIS
SYSTEM, THEREFORE A GENERAL MODEL BLEND IS PREFERRED.
...MID-LEVEL TROUGH AMPLIFYING INTO THE WESTERN U.S. THIS WEEKEND
AND REACHING THE CENTRAL PLAINS MONDAY...
...SURFACE LOW ORGANIZING EAST OF THE MISSISSIPPI RIVER MONDAY
INTO TUESDAY MORNING...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS, 12Z ECMWF, 12Z UKMET BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE
TIMING DIFFERENCES AT 500 MB SHOW UP IN THE DETERMINISTIC GUIDANCE
BY MONDAY AFTERNOON WITH THE 00Z NAM OUTRACING THE REMAINING
GUIDANCE ACROSS THE ROCKIES. LOOKING AT THE ENSEMBLE SPAGHETTI
PLOTS AT 500 MB, THE NAM DOES NOT SHOW UP AS AN OUTLIER BUT DOES
LIE TOWARD THE FASTER END OF THE LATEST ENSEMBLE GUIDANCE
(INITIALIZED 12Z/13). TRENDS IN THE ENSEMBLES OVER THEIR PAST 4
12/00Z CYCLES SHOW OPPOSING TRENDS WITH THE GEFS FASTER AND ECENS
SLOWER. THEREFORE, THE PREFERENCE IS TO BE IN THE MIDDLE OF THE
LATEST ENSEMBLE SPREAD, WHICH IS NEAR A BLEND OF THE SLIGHTLY
FASTER 00Z GFS/12Z UKMET AND SLOWER 12Z ECMWF. POOR RUN TO RUN
CONSISTENCY LOWERS CONFIDENCE BELOW AVERAGE.
...MID-LEVEL SHORTWAVE NEARING THE UPPER MISSISSIPPI VALLEY
TUESDAY MORNING...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 12Z CMC BLEND
CONFIDENCE: AVERAGE
THE MODELS ARE IN DECENT AGREEMENT WITH THIS SYSTEM OUTSIDE OF THE
FASTER 12Z CMC. HOWEVER, ENSEMBLE SPREAD IS SOMEWHAT GREATER THAN
THE NON 12Z CMC AGREEMENT WOULD SUGGEST. THEREFORE, A NON 12Z CMC
BLEND IS PREFERRED GIVEN STRONGER SUPPORT FOR A SOLUTION SLOWER
THAN THE FASTER 12Z CMC, BUT WITH ONLY AVERAGE CONFIDENCE.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
OTTO
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