Prognostic Meteorological Discussion
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444
FXUS10 KWNH 280633
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
232 AM EDT WED JUN 28 2017

VALID JUN 28/0000 UTC THRU JUL 01/1200 UTC

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

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


DEEP-LAYERED LOW MOVING BY THE NORTHERN PLAINS/GREAT LAKES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECMWF/GFS COMPROMISE; CONFIDENCE AVERAGE

THE GUIDANCE CONTINUES TO DIVERGE WITH THE POSITION OF THIS
SYSTEM`S SURFACE LOW FROM LATE FRIDAY ONWARD.  THE 00Z UKMET
SHIFTED HUNDREDS OF MILES EAST AND 15 HPA WEAKER WITH THE SYSTEM
AS ITS UPPER SHORTWAVE IS BROADER -- SO BROAD THAT IT KNOCKS OFF
THE TOP OF THE DOWNSTREAM RIDGE, WHICH IS A PROBLEM ALL THE
GUIDANCE SHOWS FROM TIME TO TIME.  THE 00Z NAM SUFFERS FROM
SIGNIFICANT GRIDSCALE FEEDBACK AND SHOWS WHAT APPEARS TO BE A
SMALL CONVECTIVE LOW DEEPENING ACROSS MI, WHICH IS UNLIKELY.  THE
00Z CANADIAN IS NOW WELL SOUTH OF THE OTHER DETERMINISTIC AND 12Z
ENSEMBLE GUIDANCE.  A COMPROMISE OF THE 00Z GFS/00Z ECMWF ACCOUNTS
FROM THE BROADER THAN USUAL SPREAD SEEN IN THE 12Z ENSEMBLE
GUIDANCE, AND IS PREFERRED WITH CONFIDENCE NO BETTER THAN AVERAGE


SHORTWAVE MOVING INTO THE PACIFIC NORTHWEST FRIDAY NIGHT
WEAK SHORTWAVE CROSSING UPPER MIDWEST/WESTERN GREAT LAKES
BY WED/THURS AND INTO N NEW ENGLAND FRIDAY/SAT
TROUGH LIFTING THROUGH NEW ENGLAND TODAY/WED
WEAKENING MID-LEVEL WEAKNESS ACROSS THE WESTERN GULF
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE FEATURES.  A
COMPROMISE OF THE 00Z NAM, 00Z GFS, 00Z UKMET, 00Z ECMWF, AND 00Z
CANADIAN IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE.


WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML... /ALL LOWER CASE/
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML... /ALL LOWER CASE/

ROTH
$$





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