Prognostic Meteorological Discussion
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FXUS10 KWNH 260420
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1220 AM EDT MON SEP 26 2016

VALID SEP 26/0000 UTC THRU SEP 29/1200 UTC

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

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


DEEP CYCLONE DROPPING TOWARDS OH VALLEY
SECONDARY ENERGY IN SOUTHEAST CANADA
FRONTAL WAVE MOVING OFFSHORE EASTERN SEABOARD
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/CANADIAN/UKMET BLEND
CONFIDENCE: NO BETTER THAN AVERAGE

THERE HAS BEEN SOME SOUTHWEST ADJUSTMENT SEEN IN MOST OF THE
GUIDANCE WITH THE MAIN UPPER LOW SINCE THIS TIME YESTERDAY, IN THE
DIRECTION OF THE 12Z ECMWF/00Z NAM SOLUTIONS.  A BUILDING UPSTREAM
RIDGE IN THE PLAINS COULD ALLOW FOR A MORE SOUTHERN SOLUTION.  THE
12Z ECMWF ENSEMBLE MEAN SOLUTION IS SOUTH OF THE 18Z GEFS MEAN,
BUT NOT TO THE DEGREE OF THE 12Z ECMWF.  FOR THE MOMENT, PREFER A
SOLUTION BETWEEN THE MEANS, WHICH WOULD BE A COMBINATION OF THE
00Z GFS/12Z CANADIAN/12Z UKMET, WITH CONFIDENCE NO BETTER THAN
AVERAGE.  THIS PREFERENCE APPLIES TO THE ENERGY NEAR
QUEBEC/NORTHWEST OF MAINE, WHICH SHOULD BE WEAK AND
QUASI-STATIONARY.  SHOULD THERE BE ANY FURTHER SOUTHWARD TRENDS IN
THE 00Z GUIDANCE, WHICH IS POSSIBLE IN THIS FLOW PATTERN,
ADDITIONAL ADJUSTMENT IN THE DIRECTION OF THE ECMWF MAY BE
REQUIRED ACROSS THE OHIO VALLEY/MID-ATLANTIC STATES/SOUTHEAST.
STAY TUNED.


UPPER TROUGH AMPLIFYING OFFSHORE THE NORTHWEST WED
UPPER LOW SHEARING NORTHWARD INTO THE GREAT BASIN
SYSTEM CLIPPING THE PACIFIC NORTHWEST MON NIGHT
WEAKENING UPPER TROUGH NEAR FL MONDAY AND TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE SYSTEMS.  PREFER A
COMPROMISE OF THE AVAILABLE GUIDANCE TO DEAL WITH DETAIL ISSUES,
WITH ABOVE AVERAGE CONFIDENCE.


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

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

ROTH
$$





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