Prognostic Meteorological Discussion
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000
FXUS10 KWNH 151635
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1234 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 AND GFS


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

PREFERENCE: NON-GEM CONSENSUS
CONFIDENCE: AVERAGE

MODEL SPREAD IS GRADUALLY DIMINISHING WITH REGARD TO THE NRN
STREAM TROUGH THAT DIGS SOUTH FROM CNTRL CANADA AND TWD THE NRN
PLAINS WED AND THURS. THE 00Z GEM APPEARS TO GRADUALLY BECOME A
BIT OF A STRONGER OUTLIER WITH THE HEIGHT FALLS THAT PIVOT SEWD
THROUGH THE PERIOD. HOWEVER...ALL OF THE MODELS LIKE THE IDEA OF
AN ELONGATED W/E ORIENTED TROUGH THAT DIGS SEWD AND PIVOT ACROSS
SRN CANADA WHILE CROSSING THROUGH THE NRN PLAINS/UPR MIDWEST AND
ESP THE UPR GRT LAKES REGION WED THROUGH FRI. BASED ON THE LATEST
GEFS MEAN AND ECENS MEAN FAVORING THE GLOBAL MODEL
CONSENSUS...EXCEPT THE GEM...WILL PREFER A NON-GEM 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: 00Z 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 00Z ECMWF/00Z UKMET AND
00Z GEM ARE THE SLOWEST...AND IT WAS NOTICED THAT THE 12Z GFS
TRENDED A BIT SLOWER TWD THE 00Z ECMWF SOLN IN PARTICULAR. THE
LATEST ECENS MEAN SUPPORTS THE NON-NCEP SOLNS...AND ALIGNS ITSELF
WELL WITH THE ECMWF. THE LATEST GEFS MEAN SUPPORTS THE NAM IN
PARTICULAR AND IS FASTER THAN THE CURRENT GFS. THE NAM SOLN SEEMS
TO HANG ON TO THE SFC LOW LONGER OVER THE UPR GRT LAKES REGION/SRN
ONTARIO INTO FRI...VS THE NON-NCEP CAMP. WILL PREFER THE 00Z ECMWF
SOLN WHICH HAS EXCELLENT SUPPORT FROM THE LATEST ECENS MEAN AND
OVERALL BETTER SUPPORT FROM THE GEM/UKMET SOLNS. DESPITE THE
PREFERENCE FOR THE 00Z ECMWF FOR MASS FIELDS...THE ECMWF IS
NOTABLY DRY AND LIKELY TOO DRY ACROSS PORTIONS OF THE UPR
MIDWEST/UPR GRT LAKES. PLS CONSULT THE LATEST QPFHSD AND QPFPFD
FOR DETAILS CONCERNING RAINFALL AND SNOWFALL POTENTIAL.


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

PREFERENCE: 00Z ECMWF/00Z UKMET 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
SLOWER/DEEPER OUTLIER. THE 00Z ECMWF EVENTUALLY LAGS THE GLOBAL
MODEL CONSENSUS. THE 12Z GFS IS THE FASTEST SOLN AND FOCUSES MORE
ENERGY OVER SWRN CANADA BY LATE FRI. THE 00Z GEM AND 00Z UKMET ARE
A LITTLE SLOWER THAN THE GFS. THE LATEST GEFS MEAN SUGGESTS THE
GFS IS TOO PROGRESSIVE AND TENDS TO FAVOR THE GEM/UKMET CAMP. THE
LATEST ECENS MEAN IS VERY CLOSE TO THE ECMWF. BASED ON STRONGER
MODEL CLUSTERING...AND ACCOUNTING FOR THE BROADER MODEL
SPREAD...WILL FAVOR A BLEND OF THE ECMWF AND UKMET SOLNS.


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

PREFERENCE: 12Z GFS/00Z 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. THE 12Z NAM IS OVERALL THE STRONGEST SOLN WITH
THIS SYS...WITH THE 00Z GEM THE WEAKEST. THE 00Z ECMWF/00Z UKMET
AND THE 12Z GFS ALL SUPPORT THE IDEA OF A SRN STREAM TROUGH AND
WEAK CLOSED LOW CENTER CROSSING SRN CA BY LATE THURS AND MOVING
INTO THE DESERT SOUTHWEST BY FRI. THE LATEST GEFS MEAN AND ECENS
MEAN BOTH STRONGLY SUPPORT THIS CLUSTER. WILL PREFER A GFS/ECMWF
COMPROMISE ATTM.


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

PREFERENCE: 06Z GEFS MEAN/00Z ECENS MEAN 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 00Z UKMET IS A
STRONGER/SLOWER OUTLIER AND SUGGESTS A MUCH WETTER SOLN FOR THE FL
PANHANDLE. THE 12Z NAM AND 12Z GFS FOCUS ENERGY FARTHER SOUTH INTO
THE FL PENINSULA. THE 12Z GFS IS THE FASTEST SOLN. THE 00Z GEM AND
00Z ECMWF ARE SLOWER THAN THE GFS...BUT FASTER THAN THE UKMET. THE
LATEST GEFS MEAN AND ECENS MEAN ARE NOT NEARLY AS STRONG AS THE
SLOWER UKMET OR EVEN THE ECMWF FOR THAT MATTER...BUT ARE NOT AS
PROGRESSIVE AS THE GFS. GIVEN THE OVERALL SPREAD OF THE
GUIDANCE...WILL LEAN TWD THE ENSEMBLE MEANS ATTM. CONFIDENCE IS
LIMITED.

...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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