Prognostic Meteorological Discussion
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000
FXUS10 KWNH 020716
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
315 AM EDT TUE JUN 02 2015

VALID JUN 02/0000 UTC THRU JUN 05/1200 UTC

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

00Z MODEL EVALUATION...INCLUDING FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

WELL DEVELOPED NORTHERN STREAM UPPER LOW ROLLING ACROSS NEW ENGLAND
WEAK SURFACE LOW AFFECTING MID-ATLANTIC THRU COASTAL NEW ENGLAND
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF OPERATIONAL MODELS
CONFIDENCE: ABOVE AVERAGE

A WELL DEVELOPED AND CONSOLIDATED UPPER LOW ALONG THE
ONTARIO/QUEBEC BORDER SHIFTS SHIFTS EASTWARD CLIPPING NORTHERN NEW
ENGLAND TUESDAY INTO WEDNESDAY EVENTUALLY PULLING A WEAK SURFACE
REFLECTION OUT THE MID-ATLANTIC AND DEEPENING IT OFF NOVA SCOTIA.
THE MODELS CONTINUE TO SHOW VERY GOOD AGREEMENT WITH PLACE AND
INTENSITY FOR THE LARGER SCALE FEATURE UNTIL THE SYSTEM IS OUT OF
CONUS ON WEDNESDAY NIGHT.  A BLEND OF THE OPERATIONAL MODEL RUNS
IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE.


SLOW MOVING CLOSED LOW OVER TENNESSEE RIVER VALLEY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 00Z NAM/GFS/ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A WELL DEFINED UPPER LOW CURRENTLY CENTERED ON THE CENTRAL
KENTUCKY/TENNESSEE BORDER SLOWLY SHIFTS EASTWARD ACROSS THE
SOUTHERN APPALACHIANS INTO THE CAROLINAS. THERE IS FAIRLY GOOD
AGREEMENT WITH THE TRACK AND DEPTH OF THE CLOSED LOW UNTIL ABOUT
12Z WEDNESDAY.  THE 00Z NAM/GFS MAY BE STARTING A TREND OF
BROADENING THE TROF TO THE EAST AS IT SHOWS PULSES OF SHORTWAVE
ENERGY EJECTING OUT OF BROAD SOUTHWESTERLY FLOW FROM THE WESTERN
CARIBBEAN.  CURRENT CONVECTIVE TRENDS IN THE VICINITY GIVE SOME
CREDENCE TO THIS SOLUTION OF CARIBBEAN INFLUENCE. ADDITIONAL
CONFIDENCE IS ADDED WITH A HANDFUL OF 12Z ECMWF ENSEMBLE MEMBERS
HINTING THIS DIRECTION AS WELL.  THE 00Z ECMWF ALSO HAS TRENDED
TOWARD A BROADER UPPER LEVEL TROF AND WEAK INVERTED SURFACE TROF
ALONG THE SOUTHEAST U.S. COAST AS THE WEAK IMPULSE MOVES THROUGH
THE SOUTHWESTERLY FLOW.  THE 00Z UKMET AND CMC ALSO ARE IN BETTER
LOCATION ALIGNMENT WITH THE SOLUTION BUT APPEAR A BIT WEAKER WITH
THE MAIN UPPER TROF...AND THOUGH ARE NOT ADDED TO PREFERRED
BLEND...THEY DO INCREASE OVERALL CONFIDENCE IN THIS TREND.


SHORTWAVE SHEARING OUT ALONG U.S./CANADIAN BOARDER
NORTHERN HIGH PLAINS CYCLOGENESIS
SOUTHERN STREAM SHORTWAVE EJECTING INTO CENTRAL PLAINS THURSDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE BEFORE THURSDAY...SLIGHTLY
BELOW AVERAGE ON THURSDAY INTO FRIDAY

ENERGY AT THE BASE OF NEGATIVE TILT PACIFIC TROF AT THE BEGINNING
OF THE PERIOD IS EJECTING ACROSS THE NORTHERN U.S. ROCKIES
EVENTUALLY SHEARING OUT ALONG THE U.S. CANADIAN BOARDER BY DAY 2.
A SURFACE LOW OVER EASTERN MONTANA MOVES EASTWARD AND BEGINS TO
WEAKEN INTO AN SOUTHWEST TO NORTHEAST ORIENTED SURFACE TROF NEAR
WESTERN LAKE SUPERIOR BY WEDNESDAY AFTERNOON.  THIS SURFACE TROF
CONNECTS TO A PERSISTENT CYCLONE ALONG THE COLORADO HIGH PLAINS.
THE EVOLUTION OF THIS COLORADO AND EAST-NORTHEAST ORIENTED TROF IS
HIGHLY INFLUENCED BY THE EJECTION OF A SUBTLE SHORTWAVE SOME TIME
ON THURSDAY. THE 00Z CMC CONTINUES TO BE THE MOST OUT OF PHASE
WITH THE OTHER OPERATIONAL GUIDANCE AS IT OVER AMPLIFIES AN UPPER
LEVEL TROF ACROSS MINNESOTA BY DAY 3. THE 00Z GFS ALONG WITH
STRONG CLUSTERING OF GEFS MEMBERS AND 00Z NAM RETAIN A MODERATELY
DEEP SURFACE LOW BACK IN SOUTHEAST COLORADO WITH A BROAD TROF AXIS
NORTHEAST INTO WESTERN IOWA...THIS IS ALSO SUPPORTED BY 00Z UKMET.
 THE 00Z ECMWF IS A LITTLE STRONGER AND FASTER IN THE UPPER LEVELS
AND SO LEADS TO EARLIER CONVECTION PRESSING A WEAK LOW OUT INTO
IOWA BY DAY 3 EVENTUALLY WEAKENING AND ORIENTING THE SURFACE TROF
FURTHER SOUTH THAN THE OTHER SOLUTIONS.  ANY NON-CMC SOLUTION IS
VIABLE...THOUGH THERE IS HIGHER PREFERENCE FOR 00Z GFS/GEFS
SOLUTION DUE TO HIGH CLUSTERING AS WELL AS BETTER TIMING FOR
CONVECTIVE/QPF RESPONSE TO THE EJECTION OF THE SHORTWAVE IN
COMPARISON TO 00Z ECMWF. WITH SUCH A DIFFERENCE IN THE MAIN MODEL
SOLUTIONS ON THE HANDLING OF THE THURSDAY SHORTWAVE
EJECTION...SLIGHTLY BELOW CONFIDENCE IS WARRANTED.


UPPER TROUGH RELOADING OVER THE WEST BY WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 00Z NAM/GFS/ECMWF
CONFIDENCE: ABOVE AVERAGE

STRONG PACIFIC WESTERLY JET ENTERS THE PACIFIC COASTAL ZONE BY
WEDNESDAY DROPPING A BULK OF ENERGY INTO THE DEEPENING OF UPPER
LEVEL LOW ALONG THE CALIFORNIA COAST BY THE END OF THE FORECAST
PERIOD.  REMARKABLE ECMWF AND NAEFS ENSEMBLE AGREEMENT IN THE
EVOLUTION OF THIS SYSTEM.  THE GEFS MEMBERS ALONG WITH THE GFS
HAVE BEEN THE WESTERN MEMBERS WHILE THE CMC MEMBERS THE FURTHEST
EAST.  THE 00Z ECMWF BLENDS VERY WELL WITH THE 00Z GFS/NAM AND
EVEN BEGIN TO SOLIDIFY ON A SOLUTION ON HOW TO HANDLE THE MID TO
UPPER LEVEL ENERGY ASSOCIATED WITH HURRICANE ANDRES IN THE EASTERN
PACIFIC BY FRIDAY MORNING...AND SO ARE THE PREFERRED BLEND AND
WITH GOOD RUN TO RUN CONSISTENCY TRENDS INCREASE CONFIDENCE TO
ABOVE AVERAGE.  THE 00Z CMC AND UKMET ARE NOT SIGNIFICANTLY
DIFFERENT THAN THE PREFERRED BLEND BUT SUBTLE DIFFERENCES AT THE
END OF DAY 3 AS BOTH DIG A LITTLE FASTER AND FURTHER SOUTH AND
EAST IS ENOUGH TO NOT USE A BLEND OF ALL OPERATIONAL MODELS AT
THIS TIME.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...

...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

GALLINA

$$




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