107
FXUS10 KWNH 031723
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
123 PM EDT WED JUN 03 2020
VALID JUN 03/1200 UTC THRU JUN 07/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING FINAL PREFERENCES AND CONFIDENCE
...FRONTAL WAVE MOVING FROM THE MID MS VALLEY FRI ACROSS THE
MIDWEST AND GREAT LAKES TO ONTARIO FRIDAY AND NORTHERN NEW ENGLAND
SAT...
PREFERENCE: BLEND OF 00Z ECMWF/12Z GFS
CONFIDENCE: NORMAL
THE MODELS INDICATE A FRONT BOUNDARY MOVING SLOWLY EAST FROM THE
CENTRAL PLAINS AND UPPER MS VALLEY WITH LOW PRESSURE DEVELOPING
ALONG THE FRONT IN THE MIDWEST AND THEN MOVING ACROSS THE GREAT
LAKES INTO ONTARIO. THE 00-12Z UKMET HAVE BOTH DEVELOPED STRONGER
LOW PRESSURE BUT THE 12Z FRI POSITIONS WERE OFF BY ABOUT 180 NM
(12Z RUN FURTHER EAST IN IL WITH LOW PRESSURE LOCATION). WITH THE
DEEPER LOW AND LACK OF RUN TO RUN CONTINUITY, CONFIDENCE IS LOW IN
EITHER THE 00-12Z RUNS OF THE UKMET. GIVEN BETTER AGREEMENT AMONG
THE GFS/00Z ECMWF/ECMWF ENSEMBLE MEAN, I RECOMMEND BLENDING THE
BETTER CLUSTERED SOLUTIONS.
CUT-OFF LOW MOVING FROM OFFSHORE SOUTHERN CALIFORNIA MOVING
ONSHORE FRIDAY AND INTO GREAT BASIN SATURDAY
PREFERENCE: BLEND OF THE 00Z ECMWF/12Z UKMET/12Z GFS
CONFIDENCE: SLIGHTLY ABOVE NORMAL
A CUT OFF UPPER LOW WILL MOVE SLOWLY NORTHEAST FRIDAY AND MOVE
ONSHORE INTO SOUTHERN CALIFORNIA FRIDAY.
THE SYSTEM OPENS UP AS IT MOVES INLAND IN CONFLUENT FLOW, WITH
SLIGHT TIMING DIFFERENCES. GIVEN THE 12Z UKMET TIMING WAS CLOSE
TO THE 00Z ECMWF AND THE EC MEAN, SO GOOD CLUSTERING OF SOLUTIONS
LENDS ITSELF TO A CONSENSUS-BASED APPROACH.
...CLOSED LOW DRIFTING SOUTH OFF BRITISH COLUMBIA THROUGH FRIDAY
NIGHT AND THEN OFF WASHINGTON/OREGON SATURDAY, WAVE MOVING INTO
NORTHERN HIGH PLAINS SATURDAY...
PREFERENCE: BLEND OF 12Z UKMET/00Z ECMWF/12Z GFS
CONFIDENCE: SLIGHTLY ABOVE NORMAL
AN UPPER LEVEL LOW IS EXPECTED TO DROP SOUTH, WEST OF THE BRITISH
COLUMBIA COAST, AND BE SITUATED WEST OF THE WASHINGTON COAST BY
SATURDAY MORNING.
THE LOW MAY APPROACH THE PACIFIC NORTHWEST COAST SAT NIGHT. THE
12Z NAM WAS A BIT DEEPER THAN THE OTHER MODELS, WITH GOOD
AGREEMENT AMONG THE 12Z UKMET/12Z GFS/00Z ECMWF. AT 700 MB, THE
MODELS SHOW A WAVY WARM FRONT CROSSING THE NORTHERN ROCKIES
SATURDAY AND THEN ONTO THE NORTHERN PLAINS. THE 12Z NAM HAD
STRONGER LOW PRESSURE NEAR THE SD/NE BORDER THAN OTHER MODELS, AND
THE CMC GLOBAL HAD DIFFERENT TIMING/PHASING AT 500 MB.
THE GOOD AGREEMENT AMONG THE 00Z ECMWF/12Z UKMET/12Z GFS SUPPORTS
A CONSENSUS OF THOSE 3 MODELS.
...UPPER TROUGH DRIFTING EAST ACROSS THE LOWER MS VALLEY AND
SOUTHEAST...
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE NORMAL
A BROAD UPPER TROUGH WILL TRACK EASTWARD ACROSS THE LOWER MS
VALLEY THURSDAY, AND INTO THE SOUTHEAST FRIDAY AND SATURDAY, WITH
AN UPPER RIDGE BUILDING EAST FROM THE CENTRAL PLAINS TO THE MID MS
VALLEY SAT. THE 500 MB TROUGH AXIS WILL EXTEND SOUTHWARD OVER THE
NORTHERN GULF OF MEXICO, AND THIS WILL BE IMPORTANT SINCE UPPER
LEVEL FLOW AHEAD OF IT WILL PLAY A ROLE IN THE FUTURE TRACK OF
TROPICAL STORM CRISTOBAL. THE 00Z ECMWF AND 12Z GFS ARE IN CLOSE
ENOUGH AGREEMENT ON THE MAIN FEATURES TO MERIT THE USE OF A BLEND.
..TROPICAL CYCLONE CRISTOBAL
SEE THE LATEST NHC ADVISORY FOR THE FORECAST TRACK OF CRISTOBAL
AND PREFERRED MODEL SUITE. THE CURRENT OFFICIAL TRACK IS CLOSE TO
THE 00Z ECMWF AND JUST A SHADE WEST OF THE 12Z GFS THROUGH 00Z
SUN. THE 12Z NAM/UKMET/00Z CANADIAN GLOBAL ARE FURTHER REMOVED
FROM THE OFFICIAL FORECAST LOW POSITIONS AT EACH FORECAST TIME.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
PETERSEN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page