THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


MODEL DIAGNOSTIC DISCUSSION


[Abbreviations and acronyms used in this product]
Geographic boundaries:    Map 1- [Color] [B/W Print Version]      Map 2 - [Color] [B/W Print Version]



MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
238 AM EDT SAT NOV 01 2014

VALID NOV 01/0000 UTC THRU NOV 04/1200 UTC

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


00Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/GEM AND THE
ECMWF

...DEEP TROUGH/CLOSED LOW AFFECTING THE EASTERN U.S...

PREFERENCE: BLEND OF THE 00Z GFS AND 00Z UKMET
CONFIDENCE: AVERAGE

A DEEP UPPER TROUGH AND ASSOCIATED CLOSED LOW WILL BE IMPACTING
THE MID-ATLANTIC AND NORTHEAST OVER THE NEXT COUPLE OF DAYS AS
STRONG HEIGHT FALLS DIG THROUGH THE OH VALLEY AND THE CENTRAL AND
SOUTHERN APPALACHIANS. LOW PRESSURE INITIALLY OFFSHORE THE
MID-ATLANTIC STATES WILL LIFT NORTH-NORTHEAST TO EAST OF THE
BENCHMARK SATURDAY AFTERNOON. MEANWHILE...INTENSE HEIGHT FALLS
EJECTING OFFSHORE THE SC/NC COASTAL PLAIN BY LATE SATURDAY WILL
INVIGORATE A NEW AREA OF LOW PRESSURE OFFSHORE THE MID-ATLANTIC
STATES SATURDAY NIGHT WHICH WILL THEN LIFT NORTH-NORTHEAST AND
INTENSIFY INTO A POWERFUL STORM OFFSHORE NEW ENGLAND NEAR THE GULF
OF MAINE ON SUNDAY. THE 00Z NAM IS THE FARTHEST LEFT WITH THIS
MORE DOMINANT LOW CENTER...AND SUGGESTS THE LOW GOES IN BETWEEN
THE MAINE COASTLINE AND THE WESTERN TIP OF NOVA SCOTIA.
HOWEVER...THE 00Z GFS AND 00Z UKMET ARE VERY WELL CLUSTERED ON A
SOLUTION JUST A TAD EAST OF THE 00Z NAM. THE GFS/NAM AND UKMET ALL
SUPPORT A CLOSED 500 MB CENTER RIDING NORTH THROUGH THE GULF OF
MAINE BY 12Z SUNDAY. THE NAM THOUGH IS THE DEEPEST SOLUTION. THE
00Z ECMWF HAS TRENDED A TAD FARTHER LEFT AND IS VERY CLOSE TO THE
UKMET/GFS CLUSTER. THE 00Z GEM IS THE ABSOLUTE FARTHEST EAST AND
SLOWEST. WILL PREFER A BLEND OF THE GFS AND UKMET BASED ON THE
SUPPORT FROM THE LATEST ECMWF TREND...AND THE GEFS MEAN.


...TROUGH MIGRATING THROUGH THE WESTERN AND CENTRAL U.S...
...COLD FRONT SETTLING ACROSS THE MIDWEST AND DOWN TO THE SOUTHERN
PLAINS...

PREFERENCE: BLEND OF THE 00Z UKMET AND 00Z ECMWF...NORTHERN STREAM
ENERGY
            00Z ECMWF...SOUTHERN STREAM ENERGY
CONFIDENCE: AVERAGE 
 
THE MODELS CLUSTER FAIRLY WELL WITH THE UPPER TROUGH THAT
INITIALLY COMES INTO THE WEST THROUGH SATURDAY. A SPLIT IN THE
TROUGH OCCURS ON SUNDAY...WITH A NORTHERN STREAM PORTION OF THE
TROUGH PROGRESSING THROUGH THE NORTHERN ROCKIES/NORTHERN PLAINS
AND UPPER MIDWEST SUNDAY AND MONDAY. A SOUTHERN STREAM PORTION OF
THE TROUGH DIGS THROUGH THE SOUTHWEST U.S. AND THE FOUR CORNERS
REGION.

THE 00Z GFS GRADUALLY BECOMES A BIT MORE PROGRESSIVE THAN THE
MULTI-MODEL CONSENSUS WITH THE NORTHERN STREAM ENERGY AS IT EJECTS
ACROSS THE NORTHERN TIER OF THE NATION. THE 00Z NAM...00Z
UKMET...00Z ECMWF AND 00Z GEM ARE ALL A LITTLE SLOWER AND WELL
CLUSTERED ALOFT. AT THE SURFACE...A COLD FRONT ASSOCIATED WITH THE
HEIGHT FALLS WILL PROGRESS SOUTHEAST THROUGH THE UPPER MIDWEST AND
DRAPE DOWN TOWARD THE CENTRAL AND SOUTHERN PLAINS BY MONDAY AND
TUESDAY. THE 00Z NAM TENDS TO BE THE SLOWEST SOLUTION WITH
THIS...WITH THE 00Z UKMET AND 00Z ECMWF OVERALL A LITTLE FASTER
BUT ALSO SUPPORTED BY THE LATEST ECENS MEAN.

REGARDING THE SOUTHERN STREAM ENERGY...THERE IS GOOD AGREEMENT
WITH THIS PORTION OF THE TROUGH UNTIL MONDAY...WHEN THE 00Z NAM
SUGGESTS MORE TROUGH PROGRESSION OUT TOWARD THE SOUTHERN HIGH
PLAINS. THE 00Z GFS AND 00Z GEM ARE A LITTLE SLOWER THAN THE 00Z
NAM...BUT THE 00Z UKMET AND 00Z ECMWF ARE THE SLOWEST...AND THE
LATTER TWO SOLUTIONS ACTUALLY HOLD MORE ENERGY BACK OVER THE
SOUTHWEST AND EVEN DIG ENERGY INTO NORTHWEST MEXICO WITH
SUGGESTION OF A CLOSED LOW HERE BY TUESDAY. IT WOULD APPEAR THOUGH
THAT THE 00Z UKMET IS A BIT TOO AGGRESSIVE WITH ITS CLOSED LOW
OVER NORTHWEST MEXICO. THE RELATIVELY MORE PROGRESSIVE NATURE OF
THE GFS/NAM AND GEM WITH THIS SOUTHERN STREAM ENERGY ON THE LARGER
SCALE IS LIKELY A REASON FOR THESE SOLUTIONS BEING A LITTLE SLOWER
WITH THE FRONTAL PROGRESSION OVER THE CENTRAL/SOUTHERN PLAINS...AS
THERE WOULD BE A BIT MORE INTERACTION BETWEEN THE TWO FEATURES AS
COMPARED TO THE UKMET AND ECMWF BY LATE MONDAY AND TUESDAY.
OVERALL...WPC WILL PREFER A SOLUTION TOWARD THE 00Z ECMWF AND 00Z
UKMET WITH THE NORTHERN STREAM ENERGY....AND JUST THE 00Z ECMWF
FOR THE SOUTHERN STREAM ENERGY.


...SHORTWAVE TROUGH AND COLD FRONT IMPACTING THE PACIFIC NORTHWEST
BY TUESDAY...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

A FAST-MOVING SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT WILL BE
IMPACTING COASTAL WA/OR AND THE CASCADES LATE MONDAY AND TUESDAY
WITH A MARKED INCREASE IN DEEP LAYER ONSHORE FLOW. ALL OF THE
MODELS INDICATE A STRONG PACIFIC JET PARALLELING THE FRONT BY
EARLY TUESDAY ALONG WITH A DEEP MOISTURE FETCH. THERE IS LITTLE
DIFFERENCE WITH THE MODELS ON THE LARGER SCALE ALOFT OR AT THE
SURFACE...SO WILL PREFER A GENERAL MODEL COMPROMISE TO RESOLVE ANY
SMALLER SCALE DIFFERENCES AT THIS POINT.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

ORRISON





Last Updated: 238 AM EDT SAT NOV 01 2014