Prognostic Meteorological Discussion
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000
FXUS10 KWNH 200642
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
142 AM EST MON NOV 20 2017

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

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

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


STRENGTHENING UPPER TROUGH OVER THE GULF OF MEXICO
BAROCLINIC LOW IN THE SOUTHEAST GULF WED/THU
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-ECMWF BLEND; CONFIDENCE SLIGHTLY ABOVE AVE

DESPITE GOOD AGREEMENT UPSTREAM ACROSS THE PLAINS AND WEST, ISSUES
ALOFT REMAIN IN THIS REGION WHICH LEAD TO A BIT OF SPREAD AT THE
SURFACE.  THE 00Z ECMWF WAS THE SHARPEST (THOUGH WEAKEST WITH THE
500 HPA HEIGHT FIELD) ALOFT, WHICH LED TO THE MOST SOUTHWESTERLY
SURFACE LOW.  THE 00Z GFS HAD THE STRONGEST BUNDLE OF ENERGY ALOFT
THE FARTHEST NORTH.  THE AMPLIFYING FLOW PATTERN SUGGESTS LOWER
MID-LEVEL HEIGHTS THAN THE ECMWF ADVERTISES AND A FARTHER SOUTH
MID-LEVEL BUNDLE OF ENERGY THAN SEEN IN THE 00Z GFS.  A COMPROMISE
OF THE 00Z GFS, 00Z NAM, 00Z UKMET, AND 00Z CANADIAN APPEARS BEST
HERE, WHICH IS PREFERRED WITH SLIGHTLY ABOVE AVERAGE CONFIDENCE.


NORTHEAST WEDNESDAY INTO THURSDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: MODEL BLEND; SLIGHTLY ABOVE AVE CONFIDENCE

WHILE THE 12Z ECMWF AND 00Z GFS SHOW UNUSUAL CONVECTIVE FEEDBACK
WITH A SURFACE LOW THEY TAKE INTO ATLANTIC CANADA, THEIR SOLUTIONS
DO NOT APPEAR TO CONTORT THE RAINFALL PATTERNS TOO STRONGLY ACROSS
THE NORTHEAST.  A COMPROMISE OF THE 00Z NAM, 00Z GFS, 00Z
CANADIAN, 00Z UKMET, AND 00Z ECMWF IS PREFERRED WITH SLIGHTLY
ABOVE AVERAGE CONFIDENCE.


WARM FRONT LIFTING NORTH NEAR THE NORTHWEST TUESDAY
DEEP LAYER CYCLONE OFFSHORE SOUTHWEST CANADA/THE NORTHWEST
LOW MOVING INTO THE NORTHERN PLAINS/MIDWEST WED/THU
SURFACE LOW MOVING BY THE CENTRAL US/CAN BORDER MON & TUE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE SYSTEMS.  A
COMPROMISE OF THE 00Z NAM, 00Z GFS, 00Z CANADIAN, 00Z UKMET, AND
00Z ECMWF IS ADVISED WITH ABOVE AVERAGE CONFIDENCE.


Www.wpc.ncep.noaa.gov/html/model2.shtml
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml

Roth
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