951
FXUS10 KWNH 040455
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1255 AM EDT THU JUN 04 2020
VALID JUN 04/0000 UTC THRU JUN 07/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z NAM/GFS EVALUATION INCLUDING PRELIMINARY PREFERENCES AND
CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...MID-LEVEL SHORTWAVE MOVING THROUGH ONTARIO/QUEBEC AND THE
NORTHEAST THROUGH THE WEEKEND...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
THE MODELS SHOW SIMILARLY TO ONE ANOTHER CONCERNING THE TIMING AND
STRENGTH OF A MID-LEVEL TROUGH ADVANCING EAST THROUGH SOUTHERN
CANADA AND THE NORTHEAST ALONG WITH THE RELATED SURFACE LOW. THERE
ARE SOME MINOR DIFFERENCES, BUT OVERALL, A GENERAL MODEL BLEND
WORKS HERE GIVEN THE DIFFERENCES ALL FALL WITHIN THE FAIRLY
TIGHTLY CLUSTERED ENSEMBLE GUIDANCE.
...INITIAL CUT-OFF LOW OFFSHORE SOUTHERN CALIFORNIA, MOVING
ONSHORE FRIDAY AND INTO GREAT BASIN SATURDAY WITH WEAKENING
AMPLITUDE...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 50/50 BLEND OF THE 12Z ECMWF/00Z GFS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
A CUT OFF UPPER LOW WILL MOVE SLOWLY NORTHEAST FRIDAY AND MOVE
ONSHORE INTO SOUTHERN CALIFORNIA. THE LOW OPENS UP AS IT MOVES
INLAND WITHIN CONFLUENT FLOW AND THIS IS WHERE TIMING DIFFERENCES
SHOW UP IN THE MODEL GUIDANCE. THE GFS HAS TRENDED SLOWER WHICH
LEAVES THE 00Z NAM AS THE FASTEST/FARTHEST EAST WITH THE SHORTWAVE
AS IT CROSSES THE ROCKEY MOUNTAINS. THE 12Z ECMWF/UKMET/CMC ARE
FAIRLY SIMILAR AND SLOWER THAN THE 00Z NAM/GFS. THE ENSEMBLE MEANS
SEEM TO SPLIT THE DIFFERENCE BETWEEN THE SLOWER NON-NCEP CAMP AND
THE 00Z GFS, SO A 00Z GFS/12Z ECMWF BLEND WILL BE PREFERRED FOR
THIS SYSTEM.
THE 12Z UKMET AND 12Z CMC ARE SIMILAR TO THE 12Z ECMWF WITH THEIR
TIMING AND MAY ALSO BE USED AS WELL ALONG WITH THE 12Z ECMWF.
...CLOSED LOW OFF BRITISH COLUMBIA DRIFTING SOUTH THROUGH FRIDAY
NIGHT AND THEN OFF WASHINGTON/OREGON SATURDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS, 12Z ECMWF, 12Z UKMET BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
ONLY THE 00Z NAM, WHICH IS FASTER TO TAKE MID-LEVEL HEIGHT FALLS
EASTWARD ACROSS THE NORTHWESTERN U.S. SATURDAY NIGHT INTO SUNDAY,
DIFFERS SIGNIFICANTLY FROM THE REMAINING GOOD MODEL CLUSTERING.
HOWEVER, THE 12Z CMC IS DISPLACED A BIT NORTH WITH THE CLOSED LOW
AND DOES NOT HAVE A RATHER POWERFUL 110-130 KT UPPER LEVEL JET
AXIS AS FAR SOUTH AS THE WELL CLUSTERED 12Z ECMWF, 00Z GFS AND 12Z
UKMET ON SUNDAY. THEREFORE, THE PREFERENCE IS TOWARD A BLEND OF
THE 00Z GFS, 12Z ECMWF AND 12Z UKMET.
..TROPICAL CYCLONE CRISTOBAL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z NAM, 12Z ECMWF CLOSEST TO 03Z NHC ADVISORY
CONFIDENCE: REFER TO NHC PRODUCTS
THE 00Z NAM AND 12Z ECMWF AIR FAIRLY SIMILAR WITH THE TRACK FOR
T.S. CRISTOBAL WHILE ALSO SHOWING FAIRLY SIMILAR STRENGTH TO ONE
ANOTHER. THE 12Z CMC DIFFERS THE GREATEST COMPARED TO THE 03Z NHC
ADVISORY FOR THE TRACK OF CRISTOBAL, WITH A FASTER TIMING. THE 00Z
GFS IS ALSO FASTER THAN NHC AND A BIT TO THE EAST OF THE NHC
TRACK, BUT NOT AS SIGNIFICANT AS THE 12Z UKMET WHICH FALLS ON THE
VERY EASTERN EDGE OF THE LATEST ENSEMBLE SCATTER LOW PLOTS.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
OTTO
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