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Model Diagnostics Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1851Z Jul 26, 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
251 PM EDT SAT JUL 26 2014

VALID JUL 26/1200 UTC THRU JUL 30/0000 UTC

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

...AN EVALUATION OF THE 12Z CMC/UKMET/ECMWF ALONG WITH FINAL
PREFERENCES/FORECAST CONFIDENCE...

THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


...DYNAMIC UPPER LOW MIGRATING FROM THE UPPER MIDWEST TOWARD THE
UPPER MID-ATLANTIC...
...STRONG SURFACE CYCLONE...

FINAL PREFERENCE: 12Z GFS
FORECAST CONFIDENCE: AVERAGE

A POWERFUL CLOSED LOW CURRENTLY CROSSING THE SOUTHERN
SASKATCHEWAN/MANITOBA BORDER WILL DIVE SOUTHEASTWARD TOWARD THE
UPPER MIDWEST DURING THE NEXT 24 HOURS. THE MODEL AGREEMENT
THROUGH 28/
1200Z IS REASONABLE WHICH IS IMPROVED OVER THE SPREAD SEEN IN THE
GUIDANCE YESTERDAY. HOWEVER...WITH ALL OF THE 12Z GUIDANCE
IN...THE SPREAD HAS INCREASED COMPARED TO THE PREVIOUS ISSUANCE.
THIS PRIMARILY HAS TO DO WITH THE SURFACE LOW TRACK AS THE 12Z
CMC/UKMET/GEFS MEAN RACE AHEAD OF THE OTHER MODELS. THE 12Z GFS
SEEMS TO FOLLOW THE 00Z ECMWF ENSEMBLE/09Z SREF MEANS MOST CLOSELY
AS OTHER GUIDANCE DIVERGE FROM THIS IDEA. WILL MAINTAIN THE 12Z
GFS FROM THE PRELIMINARY PREFERENCE BUT LOWER THE CONFIDENCE AS
THE UNCERTAINTY APPEARS TO HAVE GROWN SINCE EARLIER THIS MORNING.


...MEAN TROF ANCHORING NORTHEASTERN NORTH AMERICA...

FINAL PREFERENCE: BLEND OF THE 12Z GEFS/00Z ECMWF ENSEMBLE MEANS
FORECAST CONFIDENCE: ABOVE AVERAGE

AS MENTIONED IN THE PREVIOUS SECTION...MODELS ARE ADVERTISING AN
ANOMALOUS FULL-LATITUDE TROF TO AFFECT NORTHEASTERN NORTH AMERICA
TO CONCLUDE THE MONTH OF JULY. OVER THE COURSE OF THE EVOLUTION OF
THIS TROF...MODELS SHOW 500-MB HEIGHT ANOMALIES RANGING FROM 2 TO
4 STANDARD DEVIATIONS BELOW NORMAL. WILL LEAN ON THE 12Z GEFS/00Z
ECMWF ENSEMBLE MEANS TO WASH OUT SMALLER-SCALE SHORTWAVE
DIFFERENCES.


...MID-LEVEL ENERGY GENERALLY ACROSS THE CENTRAL GREAT BASIN...

FINAL PREFERENCE: BLEND OF THE 12Z GEFS/00Z ECMWF ENSEMBLE MEANS
FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE

A NUMBER OF IMPULSES LIFTING NORTHWARD AROUND THE ANTICYCLONIC
FLOW OF THE HIGH ACROSS THE FOUR CORNERS REGION WILL KEY PLAYERS
IN THE MONSOONAL THUNDERSTORM DEVELOPMENT. THE MOST IMPRESSIVE OF
THESE SHORTWAVES IS FORECAST TO REACH THE CENTRAL GREAT BASIN BY
EARLY TUESDAY IN THE VICINITY OF NORTHERN NV. BY 30/0000Z...THE
MODELS VARY WITH PLACEMENT OF THIS SYSTEM WITH THE 12Z NAM/GFS
AROUND THE OR/ID BORDER WHILE OTHER GUIDANCE ARE OFF TOWARD THE
EAST. THIS IS DEFINITELY A LOWER CONFIDENCE FORECAST GIVEN THE
EVOLUTION OF THIS DISTURBANCE IS RATHER COMPLEX INVOLVING MERGERS
OF OTHER MID-LEVEL VORT MAXIMA. WILL UTILIZE ENSEMBLE MEANS HERE
GIVEN THE UNCERTAINTY IN THIS CASE.


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

RUBIN-OSTER