Prognostic Meteorological Discussion
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FXUS10 KWNH 171640
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1239 PM EDT WED SEP 17 2014

VALID SEP 17/1200 UTC THRU SEP 21/0000 UTC

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

12Z MODEL EVALUATION...INCLUDING THE NAM AND GFS


...TROPICAL STORM ODILE...

PREFERENCE: THE LATEST NHC TRACK FORECAST

T.S. ODILE CONTINUES TO LIFT NORTHEAST ACROSS THE NORTHERN GULF OF
CALIFORNIA AND IS EXPECTED TO MOVE INLAND OVER THE NEXT 6 TO 12
HOURS OVER NWRN MAINLAND MEXICO. MEANWHILE...THE SYSTEM SHOULD
WEAKEN RAPIDLY AND BEGIN TO SHEAR APART WITH A MID LEVEL CENTER
RACING AND SHEARING EAST-NORTHEAST ACROSS THE SOUTHERN ROCKIES AND
OUT INTO THE SOUTHERN HIGH PLAINS OVER THE NEXT COUPLE OF DAYS.
THE LATEST NHC TRACK FORECAST IS CLOSEST TO A BLEND OF THE 00Z
UKMET AND 00Z ECMWF. THE ENERGY ALOFT SHEARING DOWNSTREAM SHOULD
TEND TO BE MORE PROGRESSIVE...AND RIGHT NOW A BLEND OF THE 12Z
NAM/12Z GFS AND 00Z ECMWF SEEM REASONABLE WHICH CLUSTER VERY WELL
WITH TIMING AND DEPTH...AND ALSO MAINTAINING A COHESIVE VORT
CENTER AT LEAST UNTIL THE ENERGY GETS OUT INTO THE SOUTHERN HIGH
PLAINS.


...DEEP UPPER TROUGH AFFECTING THE WESTERN STATES THROUGH SAT...

PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF
CONFIDENCE: ABOVE AVERAGE

THE LARGER SCALE RIDGE POSITIONED OVER THE WESTERN U.S. WILL SHIFT
EASTWARD AHEAD OF A BROAD UPPER TROUGH OFFSHORE THE WEST COAST
THAT WILL BE DIGGING INTO THE SOUTHWEST U.S. BY FRI. THE 00Z UKMET
IS A LITTLE STRONGER THAN THE GLOBAL MODEL CONSENSUS...BUT IN
GENERAL ALL OF THE MODELS SHOW VERY GOOD MASS FIELD AGREEMENT WITH
THE EVOLUTION OF THIS SYS THROUGH SAT. THE OVERALL BEST MODEL
CLUSTERING WOULD SUPPORT A BLEND OF THE 12Z GFS AND 00Z
ECMWF...AND THAT WILL BE THE PREFERENCE.


...UPPER TROUGH OVER THE NORTHEAST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

AN UPPER TROUGH WILL BE SWINGING THROUGH THE NORTHEAST OVER THE
NEXT 36 HOURS...AND THE LATEST GLOBAL MODELS SHOW EXCELLENT MASS
FIELD AGREEMENT THROUGH THAT TIME PERIOD AS THE ENERGY THEN LIFTS
ACROSS EASTERN CANADA. A GENERAL MODEL COMPROMISE WILL BE
PREFERRED.


...UPPER TROUGH DIGGING INTO THE NORTHERN PLAINS ON FRI...

PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE

ALL OF THE MODELS INDICATE A TROUGH DIGGING INTO THE NORTHERN
PLAINS ON FRI ALONG WITH A COLD FRONT. THE 00Z UKMET AND 00Z GEM
ARE MUCH MORE PROGRESSIVE AND SHEARED WITH THEIR SHORTWAVE ENERGY
DIGGING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST. THE 12Z
GFS/00Z ECMWF AND ESP THE 12Z NAM ARE SLOWER. THE 12Z NAM APPEARS
AS IF IT MAY BE A LITTLE TOO AMPLIFIED. WILL PREFER A BLEND OF THE
12Z GFS AND 00Z ECMWF BASED ON STRONGER MODEL CLUSTERING.


...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

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