Prognostic Meteorological Discussion
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FXUS10 KWNH 170455
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1254 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 THE 00Z NAM/GFS ALONG WITH PRELIMINARY
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...

PRELIMINARY PREFERENCE: BLEND OF THE 00Z NAM WITH THE 12Z
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 AND 12Z
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 WITH THE 12Z
ECMWF/UKMET.


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

PRELIMINARY PREFERENCE: BLEND OF THE 12Z 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 12Z UKMET. THE 00Z NAM AND 12Z ECMWF/CMC
DEPICT A SIMILAR TRACK ALBEIT WITH SOME DIFFERENCES IN TIMING. IN
SPITE OF THESE DIFFERENCES ALOFT...THE SURFACE APPEARS RELATIVELY
TAME. OVERALL...THE 12Z UKMET DOES SEEM TO RECOVER AND BECOME MORE
LIKE THE ENSEMBLE MEANS. WILL FAVOR A BLEND OF THE 12Z ECMWF/UKMET
AS THEY SEEM TO BRIDGE THE GROWING DIFFERENCES ALOFT.


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

PRELIMINARY PREFERENCE: BLEND OF THE 00Z NAM/GFS WITH THE 12Z ECMWF
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 12Z CMC WHICH IS SLOWER...THE MODELS SHOW
REASONABLE AGREEMENT THROUGH 18/1200Z. THIS IS PERHAPS DUE TO THE
CMC HANDLING THE TROPICAL CYCLONE DIFFERENTLY. BY THURSDAY
EVENING...THE 00Z NAM/GFS AND 12Z ECMWF END UP NORTH OF THE 12Z
UKMET SOLUTION ALONG THE CENTRAL GULF COAST. WPC WILL FAVOR THE
STRONGER CONSENSUS FORMED BY THE 00Z NAM/GFS AND 12Z ECMWF.


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

PRELIMINARY 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...

PRELIMINARY PREFERENCE: BLEND OF THE 00Z GFS/12Z 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
12Z CMC IS SLOWER THAN THE 18Z GEFS/21Z SREF/12Z ECMWF ENSEMBLE
MEANS WHICH HAS BEEN THE CASE THE PAST COUPLE OF DAYS. BY EARLY
FRIDAY...THE SYSTEM SHOULD SPLIT WITH SOME ENERGY JOINING THE
PROGRESSIVE NORTHERN STREAM WHILE A BULK OF THE TROF STRENGTHENING
AND CLOSING OFF ACROSS CA. THE ENSEMBLE MEANS AS IN PREVIOUS DAYS
CONTINUE TO PROVIDE A STEADY AND CONSISTENT SOLUTION TO FOLLOW.
THE 12Z CMC/UKMET END UP WEST OF THIS IDEA WHILE THE 00Z NAM IS
DISPLACED SLIGHTLY TO THE NORTH. WILL RECOMMEND THE 00Z GFS/12Z
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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