Prognostic Meteorological Discussion
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000
FXUS10 KWNH 170701
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT WED SEP 17 2014

VALID SEP 17/0000 UTC THRU SEP 20/1200 UTC

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

...AN EVALUATION OF ALL 00Z GUIDANCE ALONG WITH FINAL
PREFERENCES/FORECAST CONFIDENCE...

THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 00Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


...TROPICAL STORM ODILE...

FINAL PREFERENCE: BLEND OF THE 00Z NAM/ECMWF/UKMET
FORECAST CONFIDENCE: -------

TROPICAL STORM ODILE CURRENTLY CHURNING THE WATERS OF THE GULF OF
BAJA CA/SEA OF CORTEZ HAS A PRESSURE OF 994 MB WITH A MOTION
TOWARD THE NORTH AT 6 KNOTS. IT IS EXPECTED TO MAINTAIN ITS
STRENGTH BEFORE MAKING ANOTHER LANDFALL OVER FAR NORTHWESTERN
MEXICO WHERE IT SHOULD WEAKEN TO A TROPICAL DEPRESSION. ABUNDANT
TROPICAL MOISTURE MOVING INTO THE DESERT SOUTHWEST AND FOUR
CORNERS REGION WILL LEAD TO VERY HEAVY RAINFALL THROUGHOUT THE
PERIOD. FOR THE LATEST QPF DISCUSSION...PLEASE READ THE QPFPFD.
WITH REGARD TO THE NHC TRACK...THE 00Z NAM/21Z SREF MEAN ARE THE
ONLY SOLUTIONS WHICH ACCURATELY PORTRAY ITS CURRENTLY POSITION. BY
24 HOURS/WEDNESDAY EVENING ONWARD...THE 00Z NAM/ECMWF/UKMET
AFFORDABLE A REASONABLE SOLUTION TO THEIR TRACK. BY THURSDAY
MORNING THE SYSTEM IS FORECAST TO BECOME A POST-TROPICAL CYCLONE
WHILE EVENTUALLY DISSIPATING. THE RECOMMENDATION TO BEST MATCH
THEIR TRACK IS A BLEND OF THE 00Z NAM/ECMWF/UKMET.


...FULL LATITUDE TROF ACROSS THE NORTHEASTERN SECTOR OF NORTH
AMERICA...
...STRONG COLD FRONT/WAVE OF LOW PRESSURE CROSSING NEW ENGLAND ON
THURSDAY...

FINAL PREFERENCE: BLEND OF THE 00Z NAM/ECMWF/UKMET
FORECAST CONFIDENCE: AVERAGE

A WELL-DEFINED UPPER TROF WILL BE FEATURED ACROSS EASTERN CANADA
WITH AN AREA OF 500-MB HEIGHT FALLS CROSSING UPPER NEW ENGLAND BY
THURSDAY EVENING. RELATIVE TO ALL DETERMINISTIC/ENSEMBLE
GUIDANCE...THE 00Z GFS MAY BE TOO FLAT WITH THE SHORTWAVE.
MEANWHILE...OTHER MODELS SHOW MORE AMPLITUDE WITH THIS
SYSTEM...PARTICULARLY THE 00Z CMC WHICH IS A TREND IN THE MORE
AMPLIFIED DIRECTION. THE 00Z NAM/ECMWF/UKMET DEPICT A SIMILAR
TRACK ALBEIT WITH SOME DIFFERENCES IN TIMING. IN SPITE OF THESE
DIFFERENCES ALOFT...THE SURFACE APPEARS RELATIVELY TAME. WILL BASE
THE RECOMMENDATION ON THE MID-LEVEL PATTERN WHICH FAVORS A
COMBINATION OF THE REASONABLY CLUSTERED 00Z NAM/ECMWF/UKMET.


...MID-LEVEL ENERGY AHEAD OF ODILE MOVING FROM THE FOUR CORNERS
REGION TOWARD THE SOUTHERN PLAINS...

FINAL PREFERENCE: A NON-00Z CMC MODEL COMPROMISE
FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE

NORTH OF THE TROPICAL CIRCULATION WILL BE A BAND OF ENERGY
MIGRATING EASTWARD FROM THE FOUR CORNERS REGION TOWARD THE
SOUTHERN PLAINS/LOWER MS VALLEY THROUGH THURSDAY. WITH THE
EXCEPTION OF THE 00Z CMC WHICH IS A SLOW AND TOWARD THE
NORTH...THE MODELS SHOW REASONABLE AGREEMENT THROUGH 18/1200Z. BY
THURSDAY EVENING...THERE IS SLIGHT DIVERGENCE AMONG THE MODELS
WITH THE POSITION OF THESE SHORTWAVES. OF COURSE THE 00Z CMC
CONTINUES TO BE A LITTLE SLOWER BUT THE REMAINING MODELS AFFORD A
REASONABLE COMPROMISE TO THIS AREA. A NON-00Z CMC MODEL COMPROMISE
WILL BE THE RECOMMENDATION.


...LINGERING FRONTAL ZONE ALONG THE SOUTHEASTERN U.S...

FINAL PREFERENCE: GENERAL MODEL COMPROMISE
FORECAST CONFIDENCE: AVERAGE

THE 03Z WPC SURFACE ANALYSIS SHOWED A FRONTAL BOUNDARY STALLED
FROM THE LOWER MS VALLEY EASTWARD INTO THE SOUTHEASTERN U.S. THE
SOLUTIONS SOMEWHAT VARY AS TIME PROCEEDS FORWARD...PARTICULARLY
WITH THE TRACK OF A WEAK AREA OF LOW PRESSURE CROSSING THE WEST
COAST OF FL MIDDAY THURSDAY. A GENERAL MODEL COMPROMISE APPEARS
SUITABLE TO WASH AWAY THE SMALLER SCALE DIFFERENCES IN THE
GUIDANCE.


...STRONG UPPER TROF REACHING THE WESTERN CONUS BY LATE
WEDNESDAY/EARLY THURSDAY...

FINAL PREFERENCE: BLEND OF THE 00Z GFS/ECMWF
FORECAST CONFIDENCE: ABOVE AVERAGE

THE MID-LEVEL FLOW WILL REMAIN QUITE AMPLIFIED AS A RIDGE
INITIALLY ACROSS THE WESTERN THIRD OF THE COUNTRY ADVANCES
EASTWARD AHEAD OF SHARP HEIGHT FALLS. BY THURSDAY MORNING...THE
00Z CMC IS A TAD FASTER THAN THE WELL CLUSTERED 00Z GEFS/21Z
SREF/12Z ECMWF ENSEMBLE MEANS WHICH IS ACTUALLY A SHIFT IN THE
QUICKER DIRECTION FOR THE CMC. BY EARLY FRIDAY...THE SYSTEM SHOULD
SPLIT WITH SOME ENERGY JOINING THE PROGRESSIVE NORTHERN STREAM
WHILE A BULK OF THE TROF STRENGTHENS AND CLOSES OFF ACROSS CA. THE
ENSEMBLE MEANS AS IN PREVIOUS DAYS CONTINUE TO PROVIDE A STEADY
AND CONSISTENT SOLUTION TO FOLLOW. THE 00Z CMC/UKMET END UP WEST
OF THIS IDEA WHILE THE 00Z NAM IS DISPLACED SLIGHTLY TO THE NORTH.
WILL RECOMMEND THE 00Z GFS/ECMWF GIVEN THEIR STRONG RESEMBLANCE TO
THESE MEANS. THE CONFIDENCE WILL BE ABOVE AVERAGE GIVEN THE
STABILITY OF THE ENSEMBLES.



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

RUBIN-OSTER

$$




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