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Model Diagnostics Discussion
 
(Caution: Version displayed is not the latest version. - Issued 0644Z Sep 29, 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
244 AM EDT MON SEP 29 2014

VALID SEP 29/0000 UTC THRU OCT 02/1200 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


...WEAK CLOSED LOW/TROUGH MOVING FROM THE MIDWEST TO THE
MID-ATLANTIC BY MON...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

ONLY MINOR MODEL DIFFERENCES REMAIN WITH THIS FEATURE SO A GENERAL
MODEL COMPROMISE IS RECOMMENDED TO SMOOTH OUT ANY OF THE SHORT
TERM DIFFERENCES.


...SHORTWAVE TROUGH DIGGING INTO THE MID-ATLANTIC/SOUTHERN NEW
ENGLAND BY WED...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

A SIGNIFICANT TREND HAS BEEN SEEN IN THE GUIDANCE TO BE MORE
AMPLIFIED WITH THIS WAVE...MORE LIKE THE ECMWF AS THE UPPER WAVE
CROSSES THE GREAT LAKES AND DIGS SEWD BY WED INTO THE NRN
MID-ATLANTIC AND SRN NEW ENGLAND. THERE ARE NOT REALLY ANY
SUBSTANTIAL MASS FIELD DIFFERENCES. THE 00Z MODELS HAVE COME INTO
SUFFICIENTLY GOOD ENOUGH AGREEMENT NOW THAT A GENERAL MODEL
COMPROMISE WILL BE PREFERRED TO RESOLVE ANY SMALLER SCALE DIFFS.


...WEAK TROUGH OVER THE GULF COAST STATES EXITING OFFSHORE THE
SOUTHEAST COAST...
...WEAK SURFACE LOW OVER THE NORTHEAST GULF OF MEXICO...

PREFERENCE: NON-GEM CONSENSUS
CONFIDENCE: AVERAGE

ALL OF THE MODELS REMAIN MORE SUPPRESSED WITH A WEAK SURFACE LOW
THAT WILL DEVELOP BY EARLY MON OVER THE NERN GULF OF MEXICO AND
THEN MOVE NEWD OFFSHORE THE SOUTHEAST COAST MON NIGHT AND TUES.
THE 00Z GEM IS NOW THE STRONGEST COMPARED TO THE GLOBAL MODEL
CONSENSUS. THE 00Z NAM/00Z GFS/00Z ECMWF AND 00Z UKMET ARE
CLUSTERING MUCH BETTER NOW WITH THE SFC LOW EVOLUTION. A NON-GEM
CONSENSUS WILL BE PREFERRED ATTM AS A RESULT FOR MASS FIELDS.
HOWEVER...PLS NOTE THAT THE 00Z GFS IN PARTICULAR CONTINUES TO
SUFFER SOMEWHAT FROM CONVECTIVE FEEDBACK WHICH IS DISRUPTING ITS
QPF. PLS CONSULT THE LATEST QPFPFD FOR MORE DETAILS ON THE MODEL
PREFERENCES FOR QPF.


...DEEP TROUGH/CLOSED LOW OVER THE WEST EJECTING OUT INTO THE
NORTHERN PLAINS...

PREFERENCE: BLEND OF THE 00Z UKMET/00Z GEM AND THE 00Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE MODELS ARE IN VERY GOOD AGREEMENT IN TAKING THE CURRENT CLOSED
LOW OVER THE WEST EASTWARD ACROSS THE CNTRL ROCKIES WHERE THEN THE
BROADER UPR TROUGH IS EXPECTED TO PIVOT NEWD AND GO NEG TILT OVER
THE NRN PLAINS BY TUES. THE MODELS ALL SHOW AN AREA OF LOW
PRESSURE ASSOCD WITH THE HEIGHT FALLS THAT WILL STRENGTHEN IN THE
LEE OF THE ROCKIES AND LIFT NWD INTO SRN CANADA BY WED. THE 00Z
NAM IS THE FASTEST TO LIFT THE ENERGY NWD. THE 00Z GFS IS THE
SLOWEST BUT IS SUPPORTED BY THE LATEST GEFS MEAN. THE ECENS MEAN
FAVORS A CONSENSUS OF THE 00Z ECMWF/00Z GEM AND 00Z UKMET WHICH
CLUSTER WELL AND SPLIT THE DIFF BETWEEN SLOWER GFS AND FASTER NAM.
A BLEND OF THE NON-NCEP MODELS WILL BE PREFERRED.


...UPPER TROUGH CROSSING THE PACIFIC NORTHWEST AND DIGGING ACROSS
THE ROCKIES/HIGH PLAINS BY WED...

PREFERENCE: BLEND OF THE 00Z NAM/00Z GFS AND 00Z UKMET
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE 00Z GEM AND TO SOME EXTENT THE 00Z NAM ARE MORE AMPLIFIED WITH
THE UPPER TROUGH AS IT CROSSES THE CNTRL ROCKIES ON TUES...WITH
THE 00Z ECMWF THE WEAKEST AND MOST PROGRESSIVE. THERE HAS BEEN A
GENERAL TREND IN THE 00Z GUIDANCE TO SHOW A BIT MORE AMPLIFICATION
OF SHORTWAVE ENERGY OVER THE FOUR CORNERS REGION BY THURS...WITH
SOME HINT AT STREAM SEPARATION. THE SREF MEAN...GEFS MEAN AND
ECENS MEAN DO NOT QUITE YET SUPPORT A WELL-DEFINED SHORTWAVE
SEPARATING OUT AND AMPLIFYING OVER THE CNTRL ROCKIES AND SRN HIGH
PLAINS...BUT WITH THE STRONGER TRENDS NOTED AND WITH THE FACT THAT
ENERGY OVER THE NRN PLAINS WILL BE LIFTING NEWD ALONG THE BORDER
AND INTO CANADA...THERE IS ROOM FOR SOME STREAM SEPARATION TWD THE
SRN HIGH PLAINS. WILL PREFER A BLEND OF THE 00Z NAM/00Z GFS AND
00Z UKMET AS A RESULT.


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

ORRISON