Prognostic Meteorological Discussion
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FXUS10 KWNH 311844
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
244 PM EDT MON AUG 31 2015

VALID AUG 31/1200 UTC THRU SEP 04/0000 UTC

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

12Z MODEL EVALUATION INCLUDING FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

UPPER TROUGH FORMING OVER THE PACIFIC NORTHWEST TUE-WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM / 12Z ECMWF BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THERE ARE THE USUAL DIFFERENCES WITH THE INTENSITY AND SPEED OF
SHORTWAVE TROUGHS EMBEDDED WITHIN THE LONGER WAVE TROUGH WHICH
CREATE SUFFICIENT UNCERTAINTY WITH ITS STRUCTURE TOWARD THE END OF
THE WEEK. AT THIS TIME...THE SHAPE OF THE UPPER TROUGH IN BOTH THE
ENSEMBLE MEANS AND DETERMINISTIC CONSENSUS SUPPORT A BLEND OF THE
NAM/ECMWF WITH THE 12Z ECMWF SLOWING DOWN AN EMBEDDED SHORTWAVE
TROUGH MOVING THROUGH WRN MONTANA ON THU.


MID-UPPER LEVEL LOW OVER EAST TEXAS BY TUE MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 12Z ECMWF/UKMET MODEL CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 12Z ECMWF AND 12Z UKMET DO NOT FIT IN WITH TRENDS AND THE
REMAINING DETERMINISTIC CONSENSUS REGARDING THE TRACK OF THE
MID-UPPER LEVEL LOW OVER EAST TEXAS WHICH ORGANIZED OVER EAST
TEXAS ON TUE. THE ECMWF/UKMET TAKE THE LOW EAST...WHILE THE NON
12Z ECMWF/UKMET MODEL CONSENSUS HOLDS THE UPPER LOW CLOSER TO THE
WEST GULF OF MEXICO.


MID-UPPER LEVEL LOW OVER THE OHIO VALLEY BY TUE MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z NAM...12Z GFS...12Z ECMWF
CONFIDENCE: AVERAGE

SMALL TIMING DIFFERENCES EXIST WITH THE TRACK OF THIS UPPER
LOW...WITH THE NAM/GFS/ECMWF BEST FITTING THE MULTI-MODEL
CONSENSUS.


LOW LEVEL CIRCULATION WEST OF THE FLORIDA PENINSULA...REMNANTS OF
  TROPICAL STORM ERIKA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

A WEAK SURFACE LOW ANALYZED AT 15Z ROUGHLY 170 MILES WEST OF
NAPLES FLORIDA...APPEARS TO BE TIED TO THE REMNANTS OF TROPICAL
STORM ERIKA. OUTSIDE OF MINOR PLACEMENT/STRENGTH DIFFERENCES...THE
MODELS AGREE WITH TAKING THIS FEATURE SLOWLY NORTH AND WEST WHILE
EITHER DISSIPATING THE LOW COMPLETELY OR ELONGATING THE LOW INTO A
TROUGH AXIS IN THE VICINITY OF THE NORTHEASTERN GULF COAST. GIVEN
ONLY MINOR DETAIL DIFFERENCES...A GENERAL MODEL CONSENSUS IS
PREFERRED.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...

...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

OTTO

$$




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