Prognostic Meteorological Discussion
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000
FXUS10 KWNH 020659
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EDT TUE SEP 02 2014

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

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

==============================================
00Z MODEL EVALUATION AND PREFERENCES
==============================================
NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO
SIGNIFICANTLY AFFECT THEIR LARGE SCALE OUTPUT.
==============================================

...PACIFIC TROUGH MOVING QUICKLY AND SPURRING CYCLOGENESIS NEAR
MINNESOTA THURSDAY...

PREFERENCE: BLEND OF 00Z NAM/GFS/ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

SOME NOTEWORTHY TRENDS ARE OBSERVED WITH THIS SYSTEM. THE GEFS HAD
SIGNALED A QUICKER SOLUTION DURING EARLIER CYCLES...AND THE 12Z
ECMWF ENSEMBLE TRENDED TOWARD THE GEFS. THIS MAY BE RELATED TO A
SHARPENING SHORTWAVE KICKER SYSTEM THAT DEVELOPS OVER ALBERTA AT
THE SAME TIME THAT CYCLOGENESIS IS TAKING PLACE WITH THE LEAD WAVE
OVER ND/MN AND SOUTHWEST ONTARIO. THE 00Z NAM/GFS SHARPENED THE
ALBERTA KICKER SYSTEM EVEN FURTHER. THE ECMWF SEEMS TO STILL BE
CATCHING UP IN THAT RESPECT...BUT IT IS CLOSE ENOUGH TO THE
NAM/GFS IN RESOLVING THE LEAD WAVE...TO BE INCLUDED IN A BLEND.
NOTE THAT THE NAM MAY NOT BE IDEAL OVER SOUTHERN CANADA WHERE IT
OUTPACES THE GFS/ECMWF...BUT THE THREE MODELS SHOW BETTER
AGREEMENT ALONG THE TRAILING PORTION OF THE FRONT OVER THE U.S.
THE UKMET HAS BEEN INCONSISTENT...AND OFFERED A SLOW SOLUTION IN
THE 00Z RUN. THE CANADIAN WAS ON THE FAST SIDE.


...TROUGH SLIDING FROM THE MIDWEST TO THE NORTHEAST THROUGH
WEDNESDAY...

PREFERENCE: ANY OF THE OPERATIONAL MODELS
CONFIDENCE: ABOVE AVERAGE

WITH THE CANADIAN JOINING CONSENSUS...THERE ARE NO MEANINGFUL
LARGE SCALE DIFFERENCES AMONG THE OPERATIONAL MODELS OVER THE
EASTERN U.S ON DAYS 1 AND 2.


...TROPICAL STORM DOLLY...

PREFERENCE: NATIONAL HURRICANE CENTER FORECAST...CLOSELY MATCHED
BY THE NAM/GFS/ECMWF/CANADIAN

TROPICAL STORM DOLLY IS FORECAST TO MAKE LANDFALL EARLY WEDNESDAY
IN SOUTHERN TAMAULIP STATE IN MEXICO...ABOUT 200 MILES SOUTH OF
BROWNSVILLE TEXAS. A REMNANT CIRCULATION MAY TRACK UP THE SOUTHERN
PORTION OF THE RIO GRANDE VALLEY...REMAINING IN MEXICO...BUT A
GENERALLY MOIST ONSHORE FLOW WILL LIKELY BRING SOME RAIN TO SOUTH
TEXAS. THE MODEL SPREAD REMAINS RATHER MINIMAL REGARDING THE
TRACK. THE UKMET IS STILL THE ONLY MODEL TO MAINTAINS A MORE
ROBUST CIRCULATION AND INTENSE RAINFALL WELL AFTER LANDFALL. GIVEN
THAT THE TRACK WILL TAKE THIS SYSTEM TOWARD AT LEAST 4000 TO 6000
FOOT MOUNTAINS...A LASTING LOW LEVEL CIRCULATION ON DAYS 2 AND 3
IS LESS LIKELY. THE GFS...HOWEVER...MAY BE TOO DRY ON DAY 3 IN
NORTHERN MEXICO / SOUTHERN PORTION OF WEST GULF RFC AREA. THE
ECMWF/NAM/CANADIAN OFFER A GOOD COMPROMISE.


...EASTERLY WAVE APPROACHING FLORIDA...

PREFERENCE: ANY OF THE OPERATIONAL MODELS
CONFIDENCE: ABOVE AVERAGE

THE MODELS ARE FAIRLY SIMILAR IN HANDLING THIS LENGTHY...WESTWARD
MOVING...INVERTED TROUGH. THE UKMET AND CANADIAN SLOWED THEIR
FORWARD PROGRESSION AND STRENGTHENED THE MULTI-CYCLE CONSENSUS.
MODELS ARE ALSO SIMILAR IN THEIR PRECIPITATION OUTPUT.

...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

BURKE
$$





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