Prognostic Meteorological Discussion
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000
FXUS10 KWNH 020501
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
100 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 NAM/GFS EVALUATION AND PRELIMINARY PREFERENCES
==================================================
NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO
SIGNIFICANTLY AFFECT THEIR LARGE SCALE OUTPUT.
==================================================

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

PREFERENCE: ANY OF THE OPERATIONAL MODELS...EXCLUDING THE CANADIAN

THE 12Z CANADIAN PRODUCED A SLOWER AND DEEPER FRONTAL WAVE MOVING
ALONG THE SAINT LAWRENCE RIVER VALLEY TUESDAY EVENING. ASIDE FROM
THIS...THERE ARE NO MEANINGFUL LARGE SCALE DIFFERENCES AMONG THE
OPERATIONAL MODELS OVER THE EASTERN U.S ON DAYS 1 AND 2.


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

PREFERENCE: BLEND OF 00Z NAM/GFS WITH 12Z ECMWF

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 SOMEWHAT
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 12Z ECMWF
WAS NOT VERY PRONOUNCED THERE...BUT IS CLOSE ENOUGH TO THE NAM/GFS
IN RESOLVING THE LEAD WAVE...TO BE INCLUDED IN A BLEND. THE
OPERATIONAL GFS HAD BEEN OUT OF SYNC WITH THE GEFS...BUT THE 00Z
RUN BROUGHT THE TWO INTO PHASE...AND THE OPERATIONAL GFS CAN NOW
BE RECOMMENDED. THE 12Z UKMET AND CANADIAN WERE EITHER TOO FAST OR
OUT OF SYNC WITH THE CONSENSUS TIMELINE FOR INTENSITY OF THE
DEVELOPING CYCLONE.


...TROPICAL DEPRESSION NUMBER 5...

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

T.D. 5 IS FORECAST TO MAKE LANDFALL AS A TROPICAL STORM 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 12Z UKMET WAS THE ONLY OUTLIER...IN
MAINTAINING 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.


...EASTERLY WAVE APPROACHING FLORIDA...

PREFERENCE: BLEND OF 00Z NAM/GFS WITH 12Z ECMWF

THE MODELS ARE FAIRLY SIMILAR IN HANDLING THIS LENGTHY...WESTWARD
MOVING...INVERTED TROUGH. THE 12Z UKMET AND CANADIAN WERE SLIGHTLY
FAST.

...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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