Prognostic Meteorological Discussion
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000
FXUS10 KWNH 011644
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1243 PM EDT WED JUL 01 2015

VALID JUL 01/1200 UTC THRU JUL 05/0000 UTC

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

12Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.


UPPER TROUGH MOVING THROUGH WESTERN CANADA FRI/SAT
FRONT DROPPING INTO MONTANA SAT MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z CMC COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 00Z CMC IS FLATTER THAN THE REMAINING DETERMINISTIC/ENSEMBLE
CONSENSUS BY 00Z/05 WITH THE UPPER WAVE AND IS THEREFORE SLOWER TO
BRING A COLD FRONT INTO MONTANA. THE REMAINING GUIDANCE SHOWS GOOD
AGREEMENT WITH THIS SYSTEM.


SURFACE WAVE MOVING EWD FROM KS TO THE MID-ATLANTIC THROUGH SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS / 00Z ECMWF BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE

A LOW-MID LEVEL SHORTWAVE CURRNETLY OVER THE CNTRL PLAINS IS
EXPECTED TO REACH THE LOWER OHIO VALLEY THU NIGHT AND CNTRL
APPALACHIANS FRI NIGHT. ON FRI...THE 12Z NAM IS TOWARD THE
STRONGER/SOUTHERN SIDE OF THE GUIDANCE WITH THE LOW LEVEL WAVE
APPROACHING THE SRN-CNTRL APPALACHIANS WHILE THE 12Z GFS IS
FARTHER NORTH AND A BIT WEAKER. THE 00Z ECMWF IS FLATTER AND SHOWS
MORE EMPATHIS ON LOW PRESSURE NEARER TO THE MID-MISS VALLEY. THE
LATEST SREF/GEFS MEAN SUPPORT THE NAM/GFS WHILE THE 00Z ECMWF IS
SUPPORTED BY ITS 00Z ECMWF MEAN. THE 00Z UKMET/CMC REPRESENT TWO
EXTREMES OF THE ENVELOPE OF SOLUTIONS...WITH SOMEWHERE BETWEEN THE
STRONGER GFS AND FLATTER ECMWF BEING SUPPORTED IN THE LATEST
ENSEMBLE SCATTER LOW PLOTS.

CONFIDENCE IS REDUCED GIVEN TRENDS DO NOT SUPPORT ONE DIRECTION OR
ANOTHER IN ANY OF THE GUIDANCE.


SHORTWAVE CLIPPING THE NRN GREAT LAKES FRI/SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 12Z NAM COMPROMISE
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 12Z NAM IS THE SLOWEST/STRONGEST WITH THIS FEATURE...WITH THE
REMAINING AVAILABLE MODELS SHOWING AN AGREEABLE CONSENSUS AWAY
FROM THE NAM.


...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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