Prognostic Meteorological Discussion
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000
FXUS10 KWNH 200436
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1136 PM EST WED NOV 19 2014

VALID NOV 20/0000 UTC THRU NOV 23/1200 UTC

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

==============================================
00Z MODEL EVALUATION AND PREFERENCES
==============================================
NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO
SIGNIFICANTLY AFFECT THEIR LARGE SCALE OUTPUT.
==============================================

...NORTHWEST U.S. AND NORTHERN ROCKIES...

PREFERENCE: BLEND OF 20/00Z GFS AND 19/12Z ECMWF
CONFIDENCE: AVERAGE

A PRONOUNCED SHORTWAVE TROUGH AND STRONG WESTERLY FLOW WILL BREAK
THROUGH THE RIDGE OVER THE PACIFIC NORTHWEST AND SPREAD DOWNSTREAM
INTO THE NORTHERN ROCKIES BY SATURDAY. MODELS ARE FAIRLY
SIMILAR...ALTHOUGH THE UKMET STANDS OUT AS BEING FAST. THE 12Z
GFS...ECMWF...AND ESPECIALLY THE NAM WERE SLOWER.  THE GFS RUN TO
RUN CONTINUITY WAS GOOD WHILE THE 00Z NAM WAS SLOWER THAN THE 12Z
RUN.

...SOUTHWEST U.S. AND SOUTHERN PLAINS...

PREFERENCE: BLEND OF 20/00Z GFS AND 19/12Z ECMWF
CONFIDENCE: AVERAGE

A LOW AMPLITUDE LEAD WAVE WILL MOVE INTO THE SOUTHERN PLAINS BY
FRIDAY. THIS WILL BE FOLLOWED BY A MUCH STRONGER TROUGH DIVING
FROM CALIFORNIA INTO THE RIO GRANDE BASIN AND CROSSING TEXAS ON
DAY 3. WITH SHORT WAVELENGTH AND STRONG GRADIENTS...THIS IS A
DYNAMIC SYSTEM. SO THE VERY DEEP SOLUTIONS FROM RECENT UKMET AND
LATEST NAM RUNS CANNOT BE DISCOUNTED...BUT THE ENSEMBLES SIMPLY DO
NOT OFFER ANY SUPPORT. THE FULL GFS/ECMWF/CANADIAN ENSEMBLES FROM
THE DAY SHIFT STILL SUPPORT THE GFS AND ECMWF AS THE MOST LIKELY
SCENARIO.

...EASTERN / NORTHEASTERN U.S...

PREFERENCE: NON NAM BEYOND F72.
CONFIDENCE: ABOVE AVERAGE

THE NCEP MODELS HAD GOOD CONTINUITY WITH RESPECT TO THE A
SHORTWAVE SWINGING THROUGH THE LARGE SCALE FLOW PATTERN...

A SHORTWAVE TROUGH ROTATING THROUGH THE GREAT LAKES WILL BEGIN TO
SWING THE LARGER SCALE TROUGH EASTWARD...YIELDING MORE WARM
ADVECTION AND RIDGING INTO THE EASTERN U.S. BY FRIDAY AND
SATURDAY. ABOUT THE ONLY MODEL THAT GETS OUT OF STEP WITH THE
OTHER MODELS IS THE NAM AT ABOUT 23/00Z.  BY THAT TIME...THE
BIGGEST DIFFERENCES ARE WELL OFFSHORE.  SO GIVEN VERY GOOD
AGREEMENT IN THE MASS FIELDS OVER THIS REGION...THINK ANY OF THE
OPERATIONAL MODELS OR A CONSENSUS WORKS FINE.

...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

BURKE

$$




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