482
FXUS10 KWNH 061831
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
230 PM EDT MON JUL 06 2020
VALID JUL 06/1200 UTC THRU JUL 10/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH MODEL PREFERENCES/CONFIDENCE INTERVALS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.
NEW TROUGH MOVING INTO THE PACIFIC NORTHWEST THURSDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE GUIDANCE SHOWS GENERAL AGREEMENT WITH THE DEPTH AND
PROGRESSION OF THIS FEATURE INTO THURSDAY AFTERNOON, THOUGH THERE
HAS BEEN A SLIGHT QUICKENING TREND SEEN IN THE 12Z CANADIAN AND
12Z UKMET SOLUTION WHICH ADDS MERIT TO THE QUICKER 12Z NAM
FORECAST. A COMPROMISE OF THE 12Z GFS, 12Z ECMWF, 12Z UKMET, 12Z
NAM, AND 12Z CANADIAN IS PREFERRED (WHICH BEST FITS IN THE 12Z
GEFS/00Z ECMWF ENSEMBLE MEAN SOLUTIONS) WITH SLIGHTLY ABOVE
AVERAGE CONFIDENCE.
CLOSED LOW MOVING EAST ALONG THE WESTERN & CENTRAL US/CANADIAN
BORDER
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~
PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THIS FEATURE MOVING EAST
FROM THE PACIFIC NORTHWEST THROUGH TUESDAY NIGHT BEFORE THE 12Z
NAM BECOMES A SLOW/DEEP OUTLIER IN SOUTH-CENTRAL CANADA -- ITS
TRADITIONAL BIAS -- AND THE 12Z UKMET BECOMES THE QUICKEST. SINCE
THE FLOW PATTERN IN WHICH IT IS EMBEDDED IS FAIRLY ZONAL, WILL
PREFER A COMPROMISE OF THE 12Z GFS, 12Z ECMWF, 12Z UKMET, AND 12Z
CANADIAN (WHICH FITS IN WELL WITH THE 12Z GEFS/00Z ECMWF ENSEMBLE
MEAN SOLUTIONS) WITH SLIGHTLY ABOVE AVERAGE CONFIDENCE.
DEEP LAYER CYCLONE EDGING EAST-NORTHEAST NEAR THE VA/NC BORDER
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A DEEP LAYER CYCLONE IS EXPECTED TO MOVE SLOWLY EAST-NORTHEAST AS
A MID-LEVEL RIDGE BUILDS TO THE NORTH ACROSS THE NORTHERN
APPALACHIANS AND NEW ENGLAND. THE 12Z CANADIAN HAS TRENDED SOUTH
WHILE THE 12Z UKMET HAS SHIFTED WEST A LITTLE, LEADING TO
CONVERGING GUIDANCE. THE PROGRESSIVE RIDGE MOVING OVER THE TOP OF
THE SYSTEM ARGUES FOR A SLOWER PROGRESSION THAN THE UKMET. THE
APEX OF THE NORTHERN STREAM RIDGE (56-57N) ARGUES FOR THE LATITUDE
OF THE CLOSED CYCLONE UNDERNEATH FOR BE CENTERED IN THE 36-37N
RANGE, AGREEABLE WITH THE CURRENT GUIDANCE. WILL PREFER A
COMPROMISE OF THE 12Z GFS, 12Z NAM, 12Z UKMET, 12Z CANADIAN, AND
12Z ECMWF WITH ABOVE AVERAGE CONFIDENCE.
SHORTWAVE TROUGH MOVING BY NEW ENGLAND WEDNESDAY
WEAKENING 700 HPA TROUGH ACROSS NV/CA THROUGH THURSDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THE PROGRESSION AND DEPTH
OF THESE FEATURES, SO PREFER A COMPROMISE OF THE 12Z NAM, 12Z GFS,
00Z UKMET, 00Z CANADIAN, AND 00Z ECMWF WITH ABOVE AVERAGE
CONFIDENCE.
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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