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Model Diagnostics Discussion
 
(Caution: Version displayed is not the latest version. - Issued 0404Z Jul 21, 2014)
 
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Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1204 AM EDT MON JUL 21 2014

VALID JUL 21/0000 UTC THRU JUL 24/1200 UTC

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

00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS


...SHORTWAVE TROUGH LIFTING THROUGH THE NORTHEAST...
...BROAD WEAK TROUGH LEFT BEHIND OVER THE SOUTHEAST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE GUIDANCE IS IN VERY GOOD AGREEMENT WITH THE DETAILS OF THE
EXITING SHORTWAVE TROUGH MOVING THROUGH THE NORTHEAST AND ALSO
WITH THE DETAILS OF WHAT SHOULD BE A BROAD UPR TROUGH AND WEAK
CLOSED LOW OVER THE TN VLY AND GULF COAST STATES THROUGH THE
MIDDLE OF THE WEAK. A GENERAL MODEL COMPROMISE WILL BE FAVORED AS
A RESULT.


...DEEP UPPER TROUGH/CLOSED LOW OVER THE GULF OF AK DROPPING INTO
THE NORTHWEST...
...SURFACE LOW PRESSURE DEVELOPING IN THE LEE OF THE NORTHERN
ROCKIES...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS ARE IN EXCELLENT AGREEMENT ON DROPPING A CLOSED LOW AND
ASSOCD UPR TROUGH DOWN FROM THE GULF OF AK THE NEXT COUPLE OF DAYS
AND SWINGING IT INTO THE PAC NORTHWEST BY LATE WED. THE HEIGHT
FALLS ARE EXPECTED TO INDUCE LEESIDE CYCLOGENESIS OVER THE HIGH
PLAINS OF ALBERTA AND ALSO ERN MT BY EARLY THURS. THERE ARE SOME
SUBTLE DIFFS REGARDING DEPTH OF THE TROUGH AMONG THE MODELS...BUT
TIMING AGREEMENT IS EXCELLENT. WILL PREFER A GENERAL MODEL
COMPROMISE AS A RESULT.
 

...WEAK MID/UPPER LEVEL LOW SHEARING NORTH AND NORTHEAST OUT OF
CA...
...SURFACE LOW DEVELOPING IMPACTING THE NORTHERN PLAINS/UPPER
MIDWEST MON AND TUE...

PREFERENCE: 12Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS INDICATE THAT THE WEAK UPR LOW CURRENTLY SHEARING NWD
ACROSS CA WILL WEAKEN FURTHER AND WITH A PORTION OF THE ENERGY
THEN ADVANCING NEWD AND EWD AND THE N SIDE OF WHAT WILL BE A
STRENGTHENING SUBTROPICAL RIDGE OVER THE FOUR CORNERS REGION AND
SRN PLAINS MON AND TUES. THE ENERGY WILL REACH THE NRN PLAINS AND
UPR MS VLY BY LATER TUES AND WILL FOSTER A DEVELOPING SFC LOW THAT

WILL ADVANCE EAST AND MOVE INTO THE GRT LAKES REGION ALONG WITH A
COLD FRONT BY EARLY WED. THE COLD FRONT WILL ARRIVE ALONG THE
EASTERN SEABOARD ON THURS. THE 12Z UKMET IS THE FASTEST AND
FARTHEST NORTH MODEL WITH RESPECT TO THE SFC LOW. THE 00Z GFS IS
SLOWEST AND FARTHEST SOUTH...ALTHOUGH IT DOES REDEVELOP LOW
PRESSURE CLOSER INTO THE GLOBAL MODEL CONSENSUS OVER ONTARIO AND
QUEBEC BY 48 HRS AND ONWARD. THE GFS IS ALSO NOTED TO BE SUFFERING
FROM SOME CONVECTIVE FEEDBACK. THE 00Z NAM/12Z GEM AND 12Z ECMWF
CLUSTERED PRETTY WELL IN BETWEEN. GIVEN RATHER STRONG RUN TO RUN
CONTINUITY ON THE ECMWF...WILL PREFER THE 12Z ECMWF.


www.wpc.ncep.noaa.gov/html/model2.shtml... 
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... 

ORRISON