Prognostic Meteorological Discussion
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FXUS10 KWNH 051633
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1232 PM EDT SUN JUL 05 2015

VALID JUL 05/1200 UTC THRU JUL 09/0000 UTC

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

12Z NAM/GFS EVALUATION...INCLUDING PRELIMINARY PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


UPPER TROUGH MOVING THROUGH CNTRL/ERN CANADA MON/TUE
COLD FRONT CROSSING THE NORTHERN PLAINS/GREAT LAKES/NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM...12Z GFS...00Z ECMWF BLEND
CONFIDENCE: AVERAGE

OUTSIDE OF THE 00Z UKMET/CMC...WHICH ARE DISPLACED NORTH/SLOWER
WITH THE PORTION OF THE FRONT ACROSS THE PLAINS AND MIDWEST ON
WED...THERE ARE NO SIGNIFICANT MASS FIELD DIFFERENCES TO SPEAK OF
WITH THIS SYSTEM WHICH IMPACT THE LOWER 48.


UPPER TROUGH CROSSING THE UPPER OHIO VALLEY AND CNTRL APPALACHIANS
  THROUGH TUE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z UKMET CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

ENSEMBLE SPAGHETTI 500 MB HEIGHTS AT 588 DM HAVE SHOWED A GENERAL
QUICKENING TREND VALID 00Z/07 WITH THE UPPER TROUGH DEPARTING FROM
THE CNTRL APPALACHIANS. MOST OF THE MODELS SHOW REASONABLE
AGREEMENT HERE...BUT THE 00Z UKMET IS WEAKER AND SLIGHTLY FASTER
THAN THE AGREEABLE DETERMINISTIC/ENSEMBLE CONSENSUS.


SHORTWAVE CROSSING THE SOUTHWEST AND SOUTHERN PLAINS MON AND TUE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z ECMWF / 00Z ECMWF MEAN
CONFIDENCE: AVERAGE

A LOW-MID LEVEL SHORTWAVE...WHICH BECOMES BETTER DEFINED ACROSS
THE SRN/CNTRL PLAINS ON TUE AND WED...SHOWS SOME NOTABLE
DIFFERENCES IN THE LATEST GUIDANCE. THE 12Z GFS IS LESS DEFINED
WITH THIS FEATURE AND SHOWS WEAKER LOW PRESSURE IN THE 850-700 MB
LAYER COMPARED TO THE REMAINING MODEL CONSENSUS. THE 00Z UKMET/CMC
ARE A BIT NORTH OF THE ENSEMBLE MEANS WITH THIS FEATURE. THE 00Z
ECMWF HAS THE BEST AGREEMENT TO THE ENSEMBLES HERE..AND FITS THE
MIDDLE OF THE LATEST SPREAD AND TRENDS. THE 12Z NAM IS THE SECOND
BEST CHOICE HERE BUT IS NOT INCLUDED IN THE PREFERENCE AS ITS
SLIGHTLY STRONG WHICH TENDS TO BE A NAM BIAS.


EASTERN PACIFIC UPPER LOW HOVERING WEST OF CALIFORNIA THROUGH WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z UKMET CONSENSUS
CONFERENCE: ABOVE AVERAGE

ALL MODELS TAKE AN UPPER LOW OVER THE EASTERN PACIFIC CURRENTLY
CENTERED NEAR 35N 130W SLOWLY EASTWARD INTO THE MIDDLE OF THE
WEEK. THE 00Z UKMET IS A TAD SOUTH OF THE MULTI-MODEL CONSENSUS BY
THE END OF THE PERIOD. GIVEN THAT THE REMAINING MODELS ARE SO WELL
CLUSTERED...INCLUDING ENSEMBLE SPAGHETTI PLOTS...A NON-UKMET
CONSENSUS WILL BE 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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