098
FXUS10 KWNH 251718
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
118 PM EDT THU JUN 25 2020
VALID JUN 25/1200 UTC THRU JUN 29/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CLOSED LOW OVER ONTARIO/QUEBEC
TROUGH CROSSING THE EASTERN U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/00Z CMC/00Z ECMWF BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE 12Z GFS/00Z CANADIAN/00Z ECMWF ARE CLOSE TO THE CONSENSUS WITH
THE SURFACE CLOSED LOW AS IT TRACKS ACROSS ONTARIO AND QUEBEC.
THE 00Z UKMET AND 12Z NAM SPIN UP A LOW CROSSING THE GREAT LAKES
AND NORTHEAST THAT IS STRONGER THAN SHOWN IN THE
CANADIAN/ECMWF/GFS. WITH SUPPORT FROM THE ECMWF ENSEMBLE MEAN AND
GEFS/SREF MEANS, PREFER THE CLUSTER OF THE GFS/ECMWF/CANADIAN
GLOBAL. THE FORECAST CONFIDENCE REMAINS SLIGHTLY ABOVE AVERAGE.
STRONG SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST SAT NIGHT/EARLY
SUN-NORTHERN ROCKIES/GREAT BASIN/NORTHERN HIGH PLAINS SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 00Z ECMWF/06Z GEFS MEAN.
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE MODELS CLUSTER WELL IN DEVELOPING A 700 MB CLOSED LOW IN
WASHINGTON STATE 12Z SUN, MOVING IT SOUTHEAST TO NEAR SOUTHERN ID
OR ADJACENT BORDERING STATES 00Z MON. THE SPREAD GROWS ON SUNDAY,
WITH NORTHER SOUTH DIFFERENCES AND TYPICAL TIMING DIFFERENCES.
THE 12Z NAM LOWERS HEIGHT FURTHER NORTH THAN THE MAJORITY, AND THE
12Z GFS/00Z UKMET FURTHER SOUTH.
THE 06Z GEFS MEAN/06Z GFS AND 00Z ECMWF FORM THE MIDDLE OF THE
SUITE OF GUIDANCE SOLUTIONS 00Z MON.
THE SURFACE FRONT SAGS SOUTHEAST ACROSS THE GREAT BASIN AND
NORTHERN PLAINS SUNDAY WITH WAVES OF LOW PRESSURE ALONG THE FRONT.
MODEST TIMING DIFFERENCES EXIST, AS WELL AS STRENGTH OF LOW
PRESSURE CENTERS AS WELL.
A GENERAL MODEL BLEND WOULD WORK TO RESOLVE DIFFERENCES, WITH MORE
WEIGHT ON ON THE 00Z ECMWF/06Z GEFS MEAN.
TEXAS TO THE ARKLATEX
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/00Z CMC/00Z ECMWF BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
AS HIGH PRESSURE SFC/ALOFT BUILDS WEST ACROSS THE GULF COAST
STATES, THE 700 MB WAVE IN TEXAS DRIFTS WEST. THE 00-12Z UKMET
HAS A STRONGER ANTICYCLONE IN FL/GULF, SO IT CREATES STRONGER
HEIGHT RISES IN TX/ARKLATEX. FRI AFTERNOON. OVERALL, THERE IS
FAIRLY GOOD CLUSTERING IN THE MID LEVEL FLOW. BASED ON THIS, A
GENERAL MODEL BLEND IS PREFERRED, WITH SLIGHTLY ABOVE AVERAGE
CONFIDENCE.
...LOW FORMING NORTH OF MT 12Z SAT AND MOVING INTO SASKATCHEWAN
AND MANITOBA...
PREFERENCE: BLEND OF 12Z NAM/00Z ECMWF
CONFIDENCE: AVERAGE
THE 12Z NAM/00Z ECMWF/12Z GFS/00Z UKMET/00Z ECMWF ENSEMBLE MEAN
CLUSTER WELL WITH LOW PRESSURE NORTH OF THE MT BORDER 12Z ST.
SOLUTIONS START TO SPREAD AS THE LOW MOVES NORTHEAST TOWARDS THE
MANITOBA BORDER. THE 12Z GFS HAS SLOWER TIMING AT 00Z SUN TO 12Z
SUN. THE 12Z UKMET AND 00Z CANADIAN GLOBAL AXIS OF LOW PRESSURE IS
FURTHER SOUTH. WITH BETTER CLUSTERING AMONG THE 00Z ECMWF/ECMWF
ENSEMBLE MEAN AND NAM, A BLEND OF THESE SOLUTIONS IS PREFERRED.
CONFIDENCE IS LOWER IN THE UKMET SINCE IT CHANGED SOLUTIONS FROM
THE 00Z-12Z RUN.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
PETERSEN
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