613
FXUS10 KWNH 031627
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1127 AM EST MON FEB 03 2020
VALID FEB 03/1200 UTC THRU FEB 07/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z NAM/GFS EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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..EVOLVING FULL LATITUDE TROUGH OVER THE CENTRAL US THROUGH THU
..SURFACE WAVE DEVELOPING OVER THE LOWER MS VALLEY
MOVING INTO
THE INTERIOR MID ATLANTIC LATE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~
PREFERENCE: 12Z NAM/00Z ECMWF/00Z ECWMF ENSEMBLE MEAN BLEND
CONFIDENCE: AVERAGE
THE 12Z NAM/GFS ARE CLOSE TO THE CONSENSUS WITH THE EVOLVING
POSITIVELY TILTED LONG WAVE TROUGH OVER THE INTERMOUNTAIN WEST
THROUGH THIS EVENING. AFTER THAT TIME, THE 12Z GFS BECOMES FASTER
THAN THE CONSENSUS, AS IT IS NOT QUITE AS DEEP WITH THE EVOLVING
LONG WAVE TROUGH OVER THE ROCKIES INTO CENTRAL AND SOUTHERN
PLAINS. THIS TREND CONTINUES AS THE FULL LATITUDE TROUGH DEVELOPS
OVER THE CENTRAL US BY 07/00Z. THE GFS HAS BEEN CONSISTENTLY
FASTER WITH THIS FEATURE OVER THE PAST SEVERAL MODEL CYCLES.
BY CONTRAST, THE 12Z NAM REMAINS CLOSER TO THE CONSENSUS THROUGH
MUCH OF THE PERIOD AS THE TROUGH EVOLVES, MIRRORING THE CONSISTENT
00Z ECMWF/00Z ECMWF ENSEMBLE MEAN WITH THIS FEATURE. THE 00Z
CMC/UKMET ARE SLOWER/FASTER WITH THE LONG WAVE TROUGH
RESPECTIVELY. THE SURFACE WAVE DEVELOPING WITH THE LONG WAVE
TROUGH TRACKS FROM SOUTH TX AT 05/12Z TO THE INTERIOR MID ATLANTIC
BY THE END OF THE PERIOD. LIKE THE MID LEVEL FEATURES, THE 12Z
GFS/00Z UKMET ARE TOO QUICK WITH THE SURFACE WAVE. THE 00Z CMC
REMAINS THE SLOWER MEMBER OF THE GUIDANCE ENVELOPE.
BASED ON THE ABOVE, A BLEND OF THE 12Z NAM/00Z ECMWF/00Z ECMWF
ENSEMBLE MEAN ARE PREFERRED. BECAUSE THERE ARE SOME DIFFERENCES
WITH THE HANDLING OF THE SURFACE LOW ACROSS THE INTERIOR MID
ATLANTIC BEFORE 07/00Z, FORECAST CONFIDENCE IS AVERAGE.
...NORTHERN STREAM ENERGY TRACKING FROM BRITISH COLUMBIA TUE INTO
THE NORTHERN PLAINS/GREAT LAKES THU...
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PREFERENCE: NON-12Z GFS BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
SHORT WAVE ENERGY IN THE FAST MID LEVEL FLOW TRACKS FROM THE
CENTRAL BRITISH COLUMBIA COAST 0AT 4/12Z INTO THE NORTHERN PLAINS
BY 05/12Z. DURING THIS TIME FRAME, BOTH THE 12Z NAM/GFS ARE CLOSE
TO THE MODEL CONSENSUS. AFTER 05/12Z, THE 12Z GFS BECOMES MUCH
MORE AMPLIFIED WITH THE TROUGH OVER THE NORTHERN PLAINS/ UPPER MS
VALLEY, CLOSING OFF OVER MN/IA BY 06/12Z. BY CONTRAST, THE 12Z NAM
REMAINS CLOSE TO THE TIGHTLY CLUSTERED CONSENSUS, TAKING THE BULK
OF THE SHORT WAVE ENERGY ACROSS THE NORTHERN PLAINS INTO THE UPPER
GREAT LAKES BY THE END OF THE PERIOD.
SINCE THE 12Z GFS IS MUCH FASTER AND DEEPER WITH THE SYSTEM (EVEN
WHEN COMPARED TO THE 00Z GEFS MEAN), IT WAS EXCLUDED FROM THE
PREFERENCE. THUS, A NON-12Z GFS BLEND WAS PREFERRED WITH THIS
FEATURE, WITH SLIGHTLY ABOVE 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
HAYES
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