Prognostic Meteorological Discussion
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000
FXUS10 KWNH 050641
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
240 AM EDT WED AUG 05 2015

VALID AUG 05/0000 UTC THRU AUG 08/1200 UTC

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

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


CLOSED LOW MOVING INTO THE WEST FRIDAY
DEEP CYCLONE APPROACHING HAIDA GWAII LATE FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE GUIDANCE REMAINS IN GOOD AGREEMENT WITH THESE SYSTEMS.


POSSIBLE CLOSED LOW NEAR THE CENTRAL US/CAN BORDER FRI
PRECEDING SHORTWAVE MOVING INTO LAKE SUPERIOR FRI NIGHT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: CANADIAN/ECMWF/UKMET COMPROMISE
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE GFS AND NAM STRAY CONSIDERABLY FROM THE REMAINDER OF THE
GUIDANCE WITH THE LEADING SHORTWAVE AND ITS SURFACE LOW MOVING
ACROSS MN/WI.  ANY SYSTEMS MOVING OVER THE TOP OF THE SLOWLY
AMPLIFYING RIDGE IN THE SOUTHERN PLAINS SHOULD NOT BE OVERLY
STRONG MOVING OVER ITS APEX DUE TO SUPERGEOSTROPHIC/QUICK FLOW,
BUT THE 00Z GFS/00Z NAM MAY HAVE GONE TOO FAR.  A COMPROMISE OF
THE 00Z CANADIAN/00Z ECMWF/00Z UKMET LOOKS REASONABLE HERE, WHICH
IS PREFERRED WITH SLIGHTLY BELOW AVERAGE CONFIDENCE.


EASTERN TROUGH
SURFACE LOW NEAR THE EAST COAST SATURDAY MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/ECMWF/NAM COMPROMISE
CONFIDENCE: AVERAGE

BOTH THE 00Z CANADIAN/00Z UKMET APPEAR TO GENERATE CONVECTIVE
WAVES OF DIFFERENT TIMING WHICH DEEPENS AFTER REACHING THE
ATLANTIC -- THEIR USUAL BIAS.  WHILE THE 12Z GLOBAL ENSEMBLE
GUIDANCE IS SPREAD IS NORTH OF A 00Z GFS/00Z NAM/00Z ECMWF
COMPROMISE, IT IS UNKNOWN IF THE ECMWF ENSEMBLE MEMBERS WILL SHIFT
IN SUIT.  A COMPROMISE OF THE THREE APPEARS BEST WITH 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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