Prognostic Meteorological Discussion
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000
FXUS10 KWNH 191615
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1214 PM EDT SUN OCT 19 2014

VALID OCT 19/1200 UTC THRU OCT 23/0000 UTC

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

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


...SHORTWAVE TROUGH AMPLIFYING ACROSS THE GREAT LAKES/OH VALLEY
MON AND TUES...
...DEEP CLOSED LOW DEVELOPING OVER THE MID-ATLANTIC IMPACTING THE
NORTHEAST...

PREFERENCE: BLEND OF THE 12Z GFS/00Z ECMWF/00Z ECENS MEAN
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE MODELS SHOW STRONG AGREEMENT IN AMPLIFYING A SHORTWAVE TROUGH
ACROSS THE GRT LAKES AND INTO THE OH VLY MON AND TUES. A DEEP
CLOSED LOW IS EXPECTED TO EVOLVE OVER THE MID-ATLANTIC BY WED AS
ADDITIONAL AMPLIFICATION OCCURS. SFC LOW PRESSURE DEVELOPING ALONG
THE MID-ATLANTIC COAST LATE TUES IS PROGGED TO LIFT NEWD UP TO
JUST OFFSHORE SRN NEW ENGLAND ON WED. THE MODELS SHOW GOOD
AGREEMENT WITH THE POSITION AND DEPTH OF THE CLOSED LOW ON
WED...BUT THE 00Z UKMET IS THE STRONGEST SOLN WITH THE SFC LOW AND
TUCKS IT CLOSER INTO THE NEW ENGLAND COAST. THE 12Z GFS ACTUALLY
AGREES VERY WELL WITH THE UKMET SCENARIO...BUT ITS NOT AS STRONG
AT THE SFC. THE 00Z GEM IS A NRLY OUTLIER WITH ITS SFC LOW
PLACEMENT. THIS LEAVES THE 00Z ECMWF AND 12Z NAM WHICH ARE
REASONABLY WELL CLUSTERED FOR POSITION...BUT NOTING THAT THE NAM
IS THE WEAKEST SOLN. THE 06Z GEFS MEAN IS WEST OF THE
DETERMINISTIC GFS AND HAS THE LOW INLAND OVER SERN NY...MEANWHILE
THE 00Z ECENS MEAN IS VERY CLOSE TO THE DETERMINISTIC GFS.
ACCOUNTING FOR THE SPREAD...CONFIDENCE IS LIMITED WITH WHERE THE
SFC LOW WILL BE POSITIONED ON WED. WILL FAVOR A BLEND OF THE 12Z
GFS/00Z ECMWF AND 00Z ECENS MEAN ATTM AS AN ATTEMPT TO COMPROMISE.


...SOUTHERN STREAM CLOSED LOW OVER THE SOUTHWEST SHEARING
DOWNSTREAM...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

A SRN STREAM CLOSED LOW OVER THE SOUTHWEST IS EXPECTED TO MOVE
EAST AND WEAKEN AS IT APPROACHES THE SRN HIGH PLAINS TUES AND WED.
THE MODELS SHOW GOOD AGREEMENT ON THIS SYS DAMPENING OUT THROUGH
THE PERIOD AS ADDITIONAL HEIGHT FALLS APPROACH FROM UPSTREAM. A
GENERAL MODEL COMPROMISE WILL BE FAVORED WITH THIS SYS.


...SPLIT FLOW TROUGH MOVING THROUGH THE WEST AND OUT INTO THE HIGH
PLAINS TUES AND WED...

PREFERENCE: BLEND OF THE 00Z ECMWF/00Z GEM AND 00Z
UKMET...NORTHERN STREAM TROUGH
            BLEND OF THE 12Z NAM/12Z GFS AND 00Z ECMWF...SOUTHERN
STREAM TROUGH
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE MODELS SET UP A SPLIT FLOW REGIME OVER THE WEST AND OUT INTO
THE HIGH PLAINS BY TUES AND WED...WITH NRN STREAM TROUGHING
CROSSING THE NRN ROCKIES AND NRN PLAINS...AND SRN STREAM ENERGY
DROPPING SEWD THROUGH THE FOUR CORNERS REGION. THE 00Z UKMET/00Z
GEM AND THE 00Z ECMWF ARE MORE PROGRESSIVE WITH THE NRN STREAM
ENERGY VS THE 12Z NAM AND 12Z GFS. THE 00Z ECENS MEAN FAVORS THE
MORE PROGRESSIVE NON-NCEP CONSENSUS. REGARDING THE SRN STREAM
ENERGY...THE 00Z UKMET AND 00Z GEM ARE THE SLOWEST AND DEEPEST
SOLNS. THE 12Z NAM/12Z GFS AND 00Z ECMWF ARE A BIT FLATTER AND
MORE PROGRESSIVE. THE 06Z GEFS MEAN AND 00Z ECENS MEAN TEND TO
FAVOR A SOMEWHAT FLATTER SRN STREAM TROUGH. SO...BASED ON THE
AFOREMENTIONED MODEL DETAILS...WILL FAVOR A ECMWF/GEM/UKMET BLEND
FOR THE NRN STREAM ENERGY...AND A NAM/GFS/ECMWF BLEND WITH THE SRN
STREAM ENERGY.


...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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