Prognostic Meteorological Discussion
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000
FXUS10 KWNH 060703
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
302 AM EDT WED MAY 06 2015

VALID MAY 06/0000 UTC THRU MAY 09/1200 UTC

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

00Z MODEL EVALUATION...INCLUDING THE UKMET/CANADIAN/ECMWF AND
FINAL PREFERENCES

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SHORTWAVE OVER THE PACIFIC NORTHWEST DROPPING INTO THE SOUTHWEST
WED/THU
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS/ECMWF
CONFIDENCE: AVERAGE

THE 00Z NAM CONTINUED ITS TREND OF A SLOWER AND DEEPER SOLUTION AS
THE SHORT WAVE DROPS INTO THE SOUTHWEST STATES AND CLOSES
OFF...ESPECIALLY LATE ON DAY 1 AND PERSISTING INTO DAY 2.  THE 00Z
GFS AND THE ECMWF...WHILE SHOWING SOME MINOR RUN TO RUN
DIFFERENCES...REMAINED FAIRLY STEADY WITH ITS PROGRESSION.  SEE NO
REASON TO STRAY FAR FROM A GFS/ECMWF COMPROMISE SOLN.  THE UKMET
AND CANADIAN WERE A BIT SLOWER THAN MODEL CONSENSUS BUT NOT TO THE
DEGREE OF THE NAM.


SHORTWAVE TRACKING FROM THE SOUTHWEST TOWARDS THE CENTRAL PLAINS
WED/THU
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~
PREFERENCE: 00Z GFS/ECMWF
CONFIDENCE: AVERAGE

GIVEN THE RUN TO RUN CONSISTENCY OF THE GFS AND THE ECMWF...AND
THE FACT THAT THE 06/00Z NAM REMAINED ON SLOWER SIDE OF THE
GUIDANCE...NO REASON TO CHANGE THE PREVIOUS PREFERENCE OF THE
LATEST GFS WITH THE PREVIOUS ECMWF.


LOW PRESSURE NEAR THE SOUTHEAST COAST BY FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 06/00Z ECMWF/CANADIAN
CONFIDENCE: BELOW AVERAGE

THE 06/00Z NAM AND GFS CLUSTERED TOGETHER INTO EARLY DAY 3 WITH
RESPECT TO THE TRACK OF THE SURFACE LOW...WHICH FOR THE GFS
REPRESENTED A SLIGHT EASTWARD SHIFT COMPARED WITH THE 05/12Z RUN.
THE 06/00Z ECMWF CONTINUITY WAS PRETTY GOOD IN TAKING THE LOW ON A
TRACK TO THE EAST OF THE NAM/GFS.  DAY 2 INTO DAY 3 IS WHERE THE
NCEP MODELS TENDED TO BRING THE THEIR SURFACE LOW INLAND OR AT
LEAST VERY NEAR THE COAST LINE...WHILE THE CANADIAN/EC/UKMET ALL
TEND TO SLOW THE FORWARD SPEED OF THE LOW TO A CRAWL OFF SHORE.
FOR THE TIME BEING...THE CANADIAN AND ECMWF REPRESENT A MID RANGE
COMPROMISE AND IS ONLY MARGINALLY FAVORED OVER OTHER SOLNS AT THIS
POINT.

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

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

BANN

$$





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