587
FXUS10 KWNH 151726
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
126 PM EDT MON JUN 15 2020
VALID JUN 15/1200 UTC THRU JUN 19/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z PRELIMINARY MODEL EVALUATION INCLUDING PREFERENCES AND
FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..CLOSED LOW LINGERING ACROSS THE SOUTHEAST THROUGH WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 48HRS
ECMWF/ECENS/GFS/GEFS BLEND AFTER
CONFIDENCE: ABOVE AVERAGE
GUIDANCE IS VERY WELL CLUSTERED IN THE EVOLUTION OF THE CLOSED LOW
AS IT DIGS TOWARDS GA/SC AND THEN SPINS NEARLY IN PLACE INTO
WEDNESDAY. THEREAFTER, THE CMC BECOMES A NORTHEAST OUTLIER AS ITS
VORT IMPULSE IS MUCH STRONGER WHICH TUGS THE CENTER OF THE CLOSED
LOW FURTHER NE TOWARDS MD, WHILE THE GFS AND THE NAM FILL OUT THE
LEFT/WEST SIDE OF THE ENVELOPE BY THE END OF THE FORECAST PERIOD.
INTERESTING THAT THE GEFS MEAN IS ACTUALLY CLOSE TO THE CMC ON D3,
SUGGESTING THAT THE GFS OPERATIONAL IS LIKELY TOO FAR WEST. THIS
LEAVES THE ECMWF/ECENS AS THE CENTER OF THE GUIDANCE CONSENSUS,
WHICH HAS SOME SUPPORT FROM THE UKMET, BUT ONCE AGAIN THE UKMET
ERODES THE RIDGE TO THE NORTH A BIT TOO QUICKLY LETTING IT EJECT
OUT LATE AS WELL. A HEAVY WEIGHT OF THE ECMWF/ECENS IS SUGGESTED
FOR D3, WITH SOME LIGHT WEIGHT ON THE GEFS/GFS WHICH WILL SMOOTH
OUT SOME OF THOSE DIFFERENCES.
..SECONDARY CLOSED LOW MOVING INTO THE NORTHWEST TUESDAY
..NORTHERN PLAINS SURFACE LOWS/N-S FRONTAL ZONE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS BLEND UNTIL 17.18Z THEN
00Z ECMWF/CMC/UKMET BLEND THEREAFTER
CONFIDENCE: ABOVE AVERAGE THROUGH 17.00Z, AVERAGE THEREAFTER
THE WESTERN PREFERENCES ARE DEPENDENT ON THE INTERACTION OF A
CLOSED LOW MOVING ONSHORE AND A TROUGH ACROSS WESTERN CANADA WHICH
WILL FORM A LARGE CLOSED GYRE THROUGH THE MIDDLE OF THE WEEK.
THROUGH 48 HOURS A GENERAL CONSENSUS IS ACCEPTABLE AS THE SPREAD
AMONGST THE VARIOUS MEMBERS IS MINIMAL. HOWEVER, BY WEDNESDAY
DIFFERENCES BEGIN TO ARISE IN RESPONSE TO VARYING INTENSITIES OF A
JET STREAK AND SHORTWAVE IMPULSES. THE NAM LAGS A ROBUST SHORTWAVE
ON THE SW SIDE OF THE GYRE CAUSING THE TROUGH TO SHARPEN WELL SW
OF THE OTHER GUIDANCE, WHILE THE GFS REACHES A SIMILAR EVOLUTION
BY D3 BEING MORE ELONGATED AND POSITIVELY TILTED SW TO NE, BUT DUE
TO A FASTER PROGRESSION OF THIS SHORTWAVE ROTATING CYCLONICALLY
AROUND THE MAIN GYRE. THIS LEAVES THE NON-NCEP GUIDANCE, WHICH IS
WELL CLUSTERED WITH THE EVOLUTION OF THIS GYRE AND RE-CLOSING OF
THE UPPER LOW ACROSS THE NORTHERN ROCKIES LATE IN THE FORECAST
PERIOD.
WEISS
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page