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FXUS10 KWNH 151853
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 PM EDT TUE APR 15 2014

VALID APR 15/1200 UTC THRU APR 19/0000 UTC

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

12Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/GEM AND ECMWF


...CANADIAN TROUGH ADVANCING SOUTHEAST INTO THE NORTHERN
PLAINS/UPPER MIDWEST/GREAT LAKES...

PREFERENCE: 12Z UKMET/12Z GEM/12Z ECMWF COMPROMISE
CONFIDENCE: AVERAGE

MODEL SPREAD IS GRADUALLY DIMINISHING WITH REGARD TO THE W/E
ORIENTED NRN STREAM TROUGH THAT DIGS SOUTH FROM CNTRL CANADA ON
WED AND PIVOTS ACROSS SRN CANADA AND ADJACENT AREAS OF THE NRN
PLAINS/UPR MIDWEST AND ESP THE GRT LAKES REGION THURS AND FRI. THE
12Z NAM AND 12Z GFS DIG THEIR HEIGHT FALLS A LITTLE MORE
AGGRESSIVELY TO THE SOUTHEAST INTO THE UPR MIDWEST AND UPR GRT
LAKES REGION BY FRI...WITH THE 12Z UKMET/12Z GEM AND 12Z ECMWF A
LITTLE SLOWER TO DO SO AND FOCUSING THE BULK OF THEIR ENERGY STILL
UP ACROSS SRN CANADA. BASED ON THE LATEST GEFS MEAN AND ECENS MEAN
FAVORING THE NON-NCEP MODELS AND SUGGESTING THAT THE NAM/GFS CAMP
DIGS ENERGY A LITTLE TOO FAR SOUTH BY FRI OVER THE GRT LAKES
REGION...WILL FAVOR A NON-NCEP CONSENSUS.


...PACIFIC TROUGH DIGGING TOWARD THE CENTRAL ROCKIES/PLAINS/UPPER
MIDWEST/GREAT LAKES...
...SURFACE LOW PRESSURE EVOLUTION THROUGH THE UPPER MIDWEST/UPPER
GREAT LAKES...

PREFERENCE: 12Z ECMWF
CONFIDENCE: AVERAGE

A PORTION OF THE SHORTWAVE TROUGH CURRENTLY CROSSING THE NORTHWEST
WILL ADVANCE SEWD AND DIG TOWARD THE CNTRL ROCKIES BY WED...BEFORE
THEN PROGRESSIVELY EJECTING EAST ACROSS THE PLAINS AND LIFTING
NEWD TWD THE UPR MIDWEST BY EARLY THURS. ALL THE WHILE...LOW
PRESSURE WILL BE REDEVELOPING IN THE LEE OF THE NRN ROCKIES AND
MOVING INITIALLY SEWD AND THEN NEWD UP ACROSS THE PLAINS AND TWD
THE UPR MIDWEST/UPR GRT LAKES REGION BY THURS. ON FRI...THIS LOW
CENTER WILL BE DAMPENING OUT NEAR THE UPR GRT LAKES REGION AND SRN
ONTARIO. THE 12Z NAM IS THE FASTEST SOLN SFC AND ALOFT WITH THE
ENERGY AND IS GENERALLY THE STRONGEST. THE 12Z UKMET AND 12Z GEM
ARE THE SLOWEST SOLNS...WITH THE 12Z GFS AND 12Z ECMWF SPLITTING
THE DIFF BETWEEN THE FASTER AND SLOWER CAMPS. THE LATEST ECENS
MEAN SUPPORTS THE 12Z ECMWF VERY STRONGLY...WITH THE LATEST GEFS
MEAN JUST A TAD SLOWER THAN THE GFS. BASED ON THE LATEST TRENDS
AND MODEL SPREAD...A SOLN TWD THE 12Z ECMWF WILL BE PREFERRED FOR
MASS FIELDS. HOWEVER...DESPITE THAT...THE ECMWF IS NOTABLY DRY AND
LIKELY TOO DRY ACROSS PORTIONS OF THE UPR MIDWEST/UPR GRT LAKES AS
COMPARED TO THE REMAINING MODELS. PLS CONSULT THE LATEST QPFHSD
AND QPFPFD FOR DETAILS CONCERNING RAINFALL AND SNOWFALL POTENTIAL.


...NORTHERN TROUGH IMPACTING THE NORTHWEST THURS AND FRI...

PREFERENCE: 12Z UKMET/12Z GEM/12Z ECMWF COMPROMISE
CONFIDENCE: AVERAGE

THE MODELS SHOW RELATIVELY SIMILAR STRENGTH INITIALLY WITH THE
NEXT PACIFIC SHORTWAVE EXPECTED TO ARRIVE THURS ACROSS THE
NORTHWEST...BEFORE THEN MOVING DOWNSTREAM INTO THE NRN ROCKIES AND
NRN HIGH PLAINS BY FRI. HOWEVER...THE 12Z NAM EVENTUALLY BECOMES A
SLOW OUTLIER. THE 12Z ECMWF/12Z UKMET AND 12Z GEM ALL CLUSTER
RATHER WELL WITH THE ENERGY ATTEMPTING TO AMPLIFY A BIT OVER THE
NRN ROCKIES/NRN HIGH PLAINS BY FRI AND ARE A BIT FASTER THAN THE
12Z NAM. THE 12Z GFS THOUGH IS THE FASTEST MODEL AND APPEARS A
LITTLE TOO QUICK. THE LATEST GEFS MEAN WAS A TAD SLOWER THAN THE
GFS...AND THE LATEST ECENS MEAN SUPPORTS A SLOWER SOLN AWAY FROM
THE GFS. WILL PREFER A NON-NCEP CONSENSUS ATTM BASED ON STRONGER
MODEL CLUSTERING.


...SOUTHERN STREAM UPPER TROUGH/POSSIBLE CLOSED LOW IMPACTING THE
SOUTHWEST THURS/FRI...

PREFERENCE: 12Z GFS/12Z ECMWF COMPROMISE
CONFIDENCE: AVERAGE

A SRN STREAM TROUGH OFFSHORE WILL BE DRAGGED EASTWARD BY AN
INCREASINGLY ENERGETIC NRN STREAM FLOW IMPACTING THE NORTHWEST BY
THURS AND FRI. THE SRN STREAM ENERGY WHICH MAY INCLUDE A WEAK
CLOSED MID LVL LOW CENTER SHOULD ADVANCE INTO THE SOUTHWEST BY THE
END OF THE PERIOD. MOST OF THE MODELS WITH THE 12Z CYCLE HAVE
TRENDED A BIT STRONGER. THE 12Z GEM IS THE STRONGEST SOLN...WITH
THE 12Z UKMET NOW THE WEAKEST. THE 12Z NAM IS THE FASTEST.
MEANWHILE...THE 12Z GFS AND 12Z ECMWF ACTUALLY CLUSTER VERY WELL
ALOFT AND ARE COMPARABLE TO THE 12Z GEM FOR TIMING OF THE HEIGHT
FALLS. THE LATEST GEFS MEAN AND ECENS MEAN BOTH STRONGLY SUPPORT
THE GFS/ECMWF CAMP...AND SO THESE SOLNS WILL BE PREFERRED.


...SOUTHERN STREAM TROUGH/SUBTROPICAL CONNECTION OVER FLORIDA BY
FRI...

PREFERENCE: 12Z UKMET/12Z GEM/12Z ECMWF COMPROMISE
CONFIDENCE: BELOW AVERAGE

THE MODELS ARE INDICATING A DISTINCT SRN STREAM TROUGH DIGGING
INTO PORTIONS OF THE SOUTHEAST AND THE FL PENINSULA BY FRI...WITH
A DISTINCT SUBTROPICAL MOISTURE CONNECTION. THE 12Z UKMET/12Z GEM
AND 12Z ECMWF HAVE ALL TRENDED TWD EACH OTHER ON A SOLN THAT IS
FAIRLY AMPLIFIED AND CERTAINLY WETTER FOR THE ERN GULF COAST
REGION AND FL FOR THURS NIGHT/FRI. THE 12Z NAM AND ESP THE 12Z GFS
ARE MORE PROGRESSIVE AND SOMEWHAT WEAKER/BROADER WITH THE
TROUGHING. THE LATEST GEFS MEAN AND ECENS MEAN SUPPORT A SOMEWHAT
WEAKER SOLN...BUT BASED ON THE CLUSTERING AND TRENDS OF THE
NON-NCEP MODELS...WILL PREFER A UKMET/GEM/ECMWF COMPROMISE.
CONFIDENCE IS LIMITED...BUT IN ANY CASE...ALL OF THE MODELS
SUPPORT A WELL-ESTABLISHED SUBTROPICAL MOISTURE/JET CONNECTION.
PLS CONSULT THE LATEST QPFPFD FOR MORE DETAILS ON THE RAINFALL
POTENTIAL.

...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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