Prognostic Meteorological Discussion
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570
FXUS10 KWNH 291824
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
223 PM EDT MON MAY 29 2017

VALID MAY 29/1200 UTC THRU JUN 02/0000 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE

UPPER TROUGH MOVING INTO THE WEST COAST TUESDAY AND PERSISTING
THROUGH THU

PREFERENCE: MODEL CONSENSUS
CONFIDENCE: ABOVE AVERAGE

THE MODELS ARE IN BETTER THAN AVERAGE AGREEMENT IN SHOWING THE
UPPER TROUGH MOVING ONSHORE IN THE PACIFIC NORTHWEST AND CA
TUESDAY WITH AN INITIAL LEAD WAVE DAMPENING ACROSS WA/OR TUE NIGHT
AND THE MAIN TROUGH DRIFTING EAST THROUGH WED. MINOR
TIMING/PHASING/AMPLITUDE DIFFERENCES DEVELOP WITH A CONSENSUS
APPROACH RECOMMENDED TO MITIGATE THOSE DIFFERENCES.


SHORTWAVE TRACKING ACROSS THE SOUTHERN APPALACHIANS MON TO MID
ATLANTIC TUE TO OFFSHORE NEW ENGLAND WED

PREFERENCE: BLEND OF THE ECMWF AND GFS
CONFIDENCE: AVERAGE

THE LATEST GUIDANCE INDICATES A WAY FRONT WITH POSSIBLE MULTIPLE
LOW PRESSURE CENTERS ALONG THE BOUNDARY TO TRACK NORTHEAST ACROSS
THE SOUTHERN APPALACHIANS TONIGHT TO THE MID ATLANTIC TUE WITH LOW
PRESSURE POSSIBLY FORMING IN THE MID ATLANTIC COASTAL WATERS.  THE
MODELS CLUSTER WITH THE TIMING AND INTENSITY WITH MINOR TRACK
DIFFERENCES. A MODEL BLEND OR CONSENSUS APPROACH IS RECOMMENDED TO
HANDLE THE DIFFERENCES.


DEEP LAYERED CYCLONE DRIFTING NORTH ACROSS ONTARIO AND WAVES
PROGRESSING ACROSS THE GREAT LAKES

PREFERENCE: MODEL CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

MID LEVEL WAVES AND ASSOCIATED SFC FRONTS ROTATE AROUND THE PARENT
CIRCULATION...WITH A COLD FRONT PROGRESSING ACROSS THE GREAT LAKES
TUESDAY AND THE NORTHEAST ON WED AND OFF THE NEW ENGLAND COAST
AFTERWARD.
BOTH WITH RESPECT TO THE UPPER TROUGH AND THE TIMING OF THE
SURFACE FRONT PUSHING FROM THE GREAT LAKES INTO THE NORTHEAST
WED-THU...CLUSTERING OF SOLUTIONS IS GOOD WITH MINOR TIMING
DIFFERENCES THAT CAN BE ADJUDICATED WITH A MODEL CONSENSUS. THE
12Z ECMWF SHOWED GOOD RUN TO RUN CONTINUITY.

SOUTHERN STREAM TROUGH EJECTING NORTHEAST FROM MEXICO INTO NM AND
TEXAS

PREFERENCE: MODEL CONSENSUS
CONFIDENCE: AVERAGE

THE MODELS SHOW A 700-500 MB WAVE EJECTING NORTHEAST FROM CA AND
MEXICO INTO NM AND TEXAS TUE THROUGH WED.
WHILE THE MODELS ALL HAVE THE FEATURE...AMPLITUDE DIFFERENCES
DEVELOP WITH THE 06Z GEFS MEAN THE LEAST AMPLIFIED AND 00Z-12Z
UKMET MOST AMPLIFIED.  UNTIL BETTER AGREEMENT DEVELOPS...AN
INTERMEDIATE SOLUTION BETWEEN THE NAM AND ECMWF IS RECOMMENDED
WITH LESS WEIGHTING ON THE GEFS AND UKMET. THE 12Z ECMWF SHOWED
GOOD RUN TO RUN CONTINUITY.


WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML... /ALL LOWER CASE/
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML... /ALL LOWER CASE/

PETERSEN

$$





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