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Model Diagnostics Discussion
 
(Caution: Version displayed is not the latest version. - Issued 0650Z Jan 23, 2015)
 
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Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
150 AM EST FRI JAN 23 2015

VALID JAN 23/0000 UTC THRU JAN 26/1200 UTC

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

00Z MODEL EVALUATION WITH FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.


ENERGY DROPPING THROUGH THE WEST TODAY/TOMORROW
CLOSED LOW FORMING NEAR BAJA CALIFORNIA THIS WEEKEND
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

LAND IMPACTS WITH THIS SYSTEM ARE RELATIVELY MINOR...AND THE
MODELS ARE COMING INTO GOOD ENOUGH AGREEMENT TO RECOMMEND A
GENERAL MODEL COMPROMISE. THIS COMPROMISE IS IN AGREEMENT WITH THE
ENSEMBLE MEANS.


COLD FRONT DROPPING INTO THE GREAT LAKES AND NORTHEAST SAT/SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 00Z NAM/UKMET/CMC HAVE TRENDED TOWARD THE GOOD CONTINUITY OF
THE 00Z GFS AND 00Z ECMWF. A GENERAL MODEL COMPROMISE CAN BE USED
WHICH AGREES WITH THE ENSEMBLE MEANS.


ONSHORE FLOW INTO THE PACIFIC NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z ECMWF
CONFIDENCE: AVERAGE

MOST OF THE SHORTWAVE IMPACTS WILL BE NORTH OF WASHINGTON
STATE...BUT THE ONE SHORTWAVE WILL TAKE A SURFACE LOW AND
ASSOCIATED FRONT INTO THE PACIFIC NORTHWEST. THE 00Z ECMWF IS
CLOSEST TO THE ENSEMBLE MEANS IN POSITION...AND STRENGTH. THE
OTHER GUIDANCE IS EITHER OFF IN TIMING OR STRENGTH. THE 00Z ECMWF
MADE ONLY MINOR ADJUSTMENTS FROM ITS 12Z RUN FOR THE NORTHWEST
CONUS.


SHORTWAVE DROPPING TOWARDS THE UPPER MIDWEST SUN MORNING AND THE
ACCOMPANYING SURFACE LOW DIVING INTO THE MIDWEST/GREAT LAKES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 2/3 12Z ECWMF...1/3 00Z GFS BLEND
CONFIDENCE: AVERAGE

THE 00Z NAM IS THE MOST DIFFERENT WITH A SHORTWAVE DIVING THROUGH
THE UPPER MIDWEST ON SUN COMPARED TO THE REMAINING MODELS...BEING
MUCH FLATTER THAN THE REMAINING GUIDANCE. THE ENSEMBLE MEANS
CONTINUE TO SUPPORT A DEEPER UPPER TROUGH WITH MUCH OF THE
GUIDANCE COMING TOWARD THIS IDEA. BY LATE SUN NIGHT...THE GFS
APPEARS TOO FAST/STRONG ALONG THE EAST COAST...WITH THE 00Z
ECMWF/UKMET LIKELY TOO DEEP GIVEN ENSEMBLE SPREAD...BUT THE 00Z
CMC APPEARS REASONABLE AS A SECOND OPTION TO THE 2/3 12Z ECMWF /
1/3 00Z GFS BLEND. THE 12Z ECMWF IS ON THE WEAKER SIDE OF THE
GUIDANCE...BUT LOOKS OKAY ON TIMING...AND WHEN BLENDED SOME WITH
THE STRONGER 00Z GFS...A DECENT COMPROMISE IS REACHED.


DEEPENING SURFACE LOW TRACKING UP THE EAST COAST FRI-SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z NAM COMPROMISE
CONFIDENCE: AVERAGE

FROM 12Z SAT THROUGH 00Z SUN...THE ENSEMBLES HAVE TRENDED QUICKER
SINCE YESTERDAY REGARDING A SURFACE LOW JUST OFF OF THE EAST
COAST. MOST OF THE 00Z MODELS HAVE ALSO ADJUSTED FASTER...BUT THE
NAM APPEARS TO BE TOO QUICK WITH RESPECT TO THE ENSEMBLES. THE 12Z
ECMWF IS CLOSEST TO THE MIDDLE OF THE SPREAD WITH THE 00Z ECMWF
ADJUSTING A LITTLE FASTER/STRONGER WITH THE SURFACE LOW. SPREAD IS
SHRINKING AS THE EVENT DRAWS NEARER...BUT THE 00Z NAM STANDS OUT
FROM THE REMAINING...RELATIVELY WELL CLUSTERED...MODELS.


www.wpc.ncep.noaa.gov/html/model2.shtml...

www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

OTTO