248
FXUS10 KWNH 091842
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
141 PM EST SUN FEB 09 2020
VALID FEB 09/1200 UTC THRU FEB 13/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH FINAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*** NOTE THAT THE 12Z UKMET WAS NOT AVAILABLE FOR THE FINAL UPDATE
***
...DIGGING TROUGH OVER THE GREAT BASIN/SOUTHWEST TODAY AND
EJECTING EAST TOWARD THE SOUTHERN PLAINS BY TUESDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z GFS/12Z ECMWF/12Z CMC
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE ENSEMBLE GUIDANCE HAS BEEN FAIRLY CONSISTENT OVER THEIR PAST 3
12/00Z CYCLES, WITH PERHAPS A SUBTLE NUDGE TO BE FASTER WITH THE
CLOSED LOW PROGRESSING ACROSS THE SOUTHWEST. THE PREFERENCE IS TO
BE SOMEWHERE CLOSE TO THE LATEST GEFS/ECMWF MEANS WHICH ARE BEST
REPRESENTED BY A 12Z GFS/12Z ECMWF/12Z CMC BLEND.
WHILE THE GFS HAS TRENDED SLOWER FROM ITS PREVIOUSLY FASTER
SOLUTIONS, THE 12Z NAM HAS DONE THE OPPOSITE AND TRENDED FASTER
FROM ITS PREVIOUSLY SLOWER SOLUTIONS AND AWAY FROM THE BETTER
MODEL CLUSTERING. THE 00Z UKMET/CMC APPEAR TO BE SLOW ENOUGH,
RELATIVE TO THE LATEST ENSEMBLE MEANS, TO EXCLUDE THEM FROM THE
PREFERENCE. HOWEVER, A QUICKER TREND IN THE 12Z CMC PLACES IT NEAR
THE TIMING OF THE 12Z ECMWF. OF THE PREFERRED 12Z GFS/ECMWF/CMC,
THE 12Z GFS IS A LITTLE FASTER THAN THE 12Z ECMWF/CMC WITH A
BLENDED APPROACH LOOKING BEST AT THIS TIME.
..NORTHERN STREAM TROUGH CROSSING THE GREAT LAKES TODAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
ONLY MINOR DIFFERENCES REMAIN WITH THIS SYSTEM SUCH THAT A GENERAL
MODEL BLEND CAN BE USED.
..NORTHERN STREAM TROUGH/FRONT OVER THE MIDWEST BY TUESDAY
...ENERGY CROSSING THE GREAT LAKES/NORTHEAST BY WEDNESDAY
MORNING...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THERE ARE ONLY MINOR DIFFERENCES WITH THIS SYSTEM CONCERNING
TIMING AND AMPLITUDE OF THE MID-LEVEL WAVE AND SURFACE REFLECTION.
A GENERAL MODEL BLEND SHOULD BE SUITABLE REGARDING THIS SYSTEM.
..QUASI-STATIONARY FRONT OVER THE GULF COAST STATES BY TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NEAREST TO THE 12Z ECMWF
12Z CMC AS A SECONDARY PREFERENCE
CONFIDENCE: AVERAGE
THERE ARE SOME LATITUDINAL DIFFERENCES THAT DEVELOP ON TUESDAY
WITH THE FRONTAL PLACEMENT ACROSS THE GULF COAST STATES. THE 12Z
GFS LOOKS REASONABLE UPSTREAM WITH A CLOSED LOW BUT HAS A WEAKER
RIDGE SITUATED OFF OF THE SOUTHEASTERN U.S. WHICH CAUSES THE FRONT
IN THE GFS TO HAVE THE FRONT FARTHER SOUTH. OVERALL, CONSIDERING
THE RIDGE TO THE SOUTH, THE UPSTREAM CLOSED LOW OVER THE SOUTHWEST
AND A SHORTWAVE/SURFACE LOW TO THE NORTH, THE PREFERENCE IS TO BE
NEAR THE 12Z ECMWF GIVEN IT IS CONSIDERED REASONABLE WITH ALL
SURROUNDING SYNOPTIC SCALE FEATURES. THE 12Z CMC CAN BE CONSIDERED
A SECOND OPTION FOR THIS SYSTEM.
..SHORTWAVE CROSSING BRITISH COLUMBIA MONDAY NIGHT
..ENERGY DROPPING SOUTHEAST ACROSS THE NORTHERN ROCKIES TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z ECMWF/NAM/CMC BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE
UNCERTAINTY HAS DECREASED COMPARED TO SATURDAY REGARDING A
SHORTWAVE THAT WILL ADVANCE EAST ACROSS BRITISH COLUMBIA MONDAY
NIGHT AND TOWARD THE NORTHERN ROCKIES ON TUESDAY. MODELS HAVE
CONVERGED COMPARED TO YESTERDAY BUT THE 12Z GFS HAS A NOTABLE
SLOWER TIMING OF THE SHORTWAVE COMPARED TO THE REMAINING
DETERMINISTIC GUIDANCE. GIVEN THE ENSEMBLE MEANS DO NOT SUPPORT
THE 12Z GFS AND MATCH BETTER TO A BLEND OF THE 12Z ECMWF, 12Z CMC
AND 12Z NAM, A NAM/ECMWF/CMC BLEND IS RECOMMENDED. LARGE
DIFFERENCES REMAIN IN THE ENSEMBLE GUIDANCE REGARDING A DOWNSTREAM
SURFACE LOW ON WEDNESDAY IN THE UPPER MIDWEST, BUT A 12Z NAM/12Z
ECMWF/12Z CMC BLEND IS NEAREST TO BE BEST CLUSTERING OBSERVED IN
THE ENSEMBLE GUIDANCE AT THIS TIME.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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