Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9
000
FXUS10 KWNH 031846
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
145 PM EST TUE MAR 03 2015

VALID MAR 03/1200 UTC THRU MAR 07/0000 UTC

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


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

...NORTHERN STREAM TROUGH DIGGING THROUGH THE MIDWEST/NORTHEAST...
...COLD FRONT SETTLING THROUGH THE EAST...
...SURFACE WAVE DEVELOPING ALONG THE FRONT AND IMPACTING THE
MID-ATLANTIC

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

ALL OF THE MODELS SHOW A COLD FRONT DRIVING SOUTHEASTWARD OVER THE
NEXT COUPLE OF DAYS THROUGH THE MIDWEST AND GRADUALLY ACROSS THE
MID-ATLANTIC AND SOUTHEAST AS ARCTIC HIGH PRESSURE NOSES SOUTH
DOWN THROUGH THE PLAINS. THE 12Z UKMET/12Z NAM AND 12Z GEM ARE THE
SLOWEST WITH THE FRONTAL TIMING...WITH THE 12Z GFS AND 12Z ECMWF
GENERALLY A BIT FASTER AND ESPECIALLY AS IT RELATES TO THE
MID-ATLANTIC AND SOUTHEAST LATE WED THROUGH THURS. THE UKMET/NAM
AND GEM THOUGH HAVE ALL TRENDED TOWARD THE SLIGHTLY
FASTER/SUPPRESSED GFS/ECMWF AS WELL. MEANWHILE...A SHORTWAVE
TROUGH IS FORECAST TO BE DIGGING SOUTHEAST ACROSS THE MIDWEST
THROUGH THE PERIOD AND SHOULD CROSS THE OH VALLEY BY LATE THURS
AND THEN THE NORTHEAST THURS NIGHT. THIS ENERGY IS EXPECTED TO
DEVELOP A WEAK AREA OF LOW PRESSURE ALONG THE AFOREMENTIONED FRONT
AND SHOULD TRACK FROM THE TN VALLEY THROUGH THE SOUTHERN
MID-ATLANTIC REGION ON THURS BEFORE EJECTING RAPIDLY OUT TO SEA.
THE 12Z GFS AND 12Z ECMWF OVERALL HAVE BETTER CONTINUITY AND
ENSEMBLE SUPPORT...INCLUDING THAT OF THE 12Z GEFS MEAN AND 00Z
ECENS MEAN. WILL PREFER A BLEND OF THE 12Z GFS AND 12Z ECMWF AT
THIS TIME.


...CLOSED LOW OFF SOUTHERN CALIFORNIA MOVING BACK INTO THE
SOUTHWEST...

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

THE MODELS SHOW REASONABLY CLOSE AGREEMENT WITH THE DETAILS OF THE
CLOSED LOW OFF SOUTHERN CA THAT SHOULD EJECT EAST AND THEN SHEAR
OUT TOWARD THE SOUTHERN PLAINS OVER THE NEXT COUPLE OF DAYS. WILL
CONTINUE TO LEAN TOWARD A BLEND OF THE GFS AND ECMWF IN KEEPING
WITH CONTINUITY.


...CLOSED LOW/TROUGH REDEVELOPING NEAR THE BAJA PENINSULA THURS
AND FRI...

PREFERENCE: BLEND OF THE 12Z NAM/12Z GEM AND 12Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS SHOW ENERGY DIGGING BACK INTO PARTS OF THE FAR
SOUTHWEST U.S. AND THE BAJA PENINSULA BY THURS AND FRI. THE 12Z
GFS IS MORE ELONGATED SW/NE WITH THE TROUGH AXIS BY THE END OF THE
PERIOD...WITH THE 12Z UKMET SUGGESTING A BETTER DEFINED UPPER LOW
WEST OF THE BAJA PENINSULA AS PART OF A REX BLOCK. THE 12Z NAM/12Z
GEM AND 12Z ECMWF ALL HAVE AN UPPER LOW A BIT FARTHER EAST
BASICALLY OVER THE NORTHERN BAJA PENINSULA OR THE NORTHERN GULF OF
CA. THE LATEST GEFS MEAN AND ECENS MEAN SUPPORT THIS CLUSTERING
AND SO A BLEND OF THESE SOLUTIONS WILL BE PREFERRED.


...SHORTWAVE MOVING DOWN THROUGH SOUTHWEST CANADA ON FRI...

PREFERENCE: 12Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS ARE FORECASTING SHORTWAVE ENERGY FROM THE GULF OF
ALASKA TO TRACK INTO WESTERN CANADA ON THURS...ATOP A STRONG
MID-LEVEL RIDGE CENTERED NEAR THE COAST OF CENTRAL CALIFORNIA. THE
12Z NAM BECOMES THE WEAKEST SOLUTION IN TIME WITH THIS
ENERGY...WITH THE 12Z GFS NOW THE STRONGEST SINCE THE 12Z
UKMET/12Z GEM AND 12Z ECMWF ALL AGREE IN SHEARING THE SYSTEM OUT
AND FLATTENING OUT THE NORTHWEST FLOW ALOFT. WILL LEAN TOWARD THE
12Z ECMWF.


...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

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.