Prognostic Meteorological Discussion
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FXUS10 KWNH 161630
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1229 PM EDT WED APR 16 2014

VALID APR 16/1200 UTC THRU APR 20/0000 UTC

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


12Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.


SYSTEM APPROACHING THE PACIFIC NORTHWEST SAT
SYSTEM MOVING ACROSS SOUTHERN CANADA FRI/SAT
SYSTEM MOVING ACROSS THE SOUTHWEST FRI/SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  GENERAL MODEL COMPROMISE
CONFIDENCE:  ABOVE AVERAGE

THE GUIDANCE SHOWS MINIMAL ISSUES WITH THE PROGRESSION AND DEPTH
OF THESE SYSTEMS, AT THE SURFACE OR ALOFT.  A GENERAL MODEL
COMPROMISE IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE CONSIDERING
THE GOOD MODEL AGREEMENT.


CLOSED LOW DEVELOPING NEAR FL FRI NIGHT/SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  GFS/ECMWF COMPROMISE
CONFIDENCE:  AVERAGE

THE SYNOPTIC PATTERN FEATURES A NORTHERN STREAM SLOWLY SHIFTING
NORTHWARD IN ADVANCE OF A SYSTEM APPROACHING WESTERN NORTH AMERICA
SATURDAY.  THIS CHANGE IN THE NORTHERN STREAM ALLOWS THE
POSSIBILITY OF CLOSED SYSTEMS ALOFT IN THE SOUTHERN STREAM, AND
THE AVAILABLE GUIDANCE BEARS THIS OUT.  THIS SOUTHEASTERN SYSTEM
HAS A CHANCE TO DIG/AMPLIFY INTO FRIDAY NIGHT BEFORE THE UPSTREAM
SYSTEM IN THE SOUTHWEST WEAKENS.  BOTH THE 00Z ECMWF/06Z GEFS
MEANS IMPLY A MORE SOUTHERN SOLUTION IS ADVISED, SIMILAR TO THEIR
OPERATIONAL RUNS, WHICH FAVORS THE ABOVE IDEA.  THE 12Z NAM IS
MORE SOUTHERLY WHILE THE 00Z CANADIAN/00Z UKMET ARE MORE
NORTHERLY.  THE 12Z GFS IS BEING CONTAMINATED BY GRIDSCALE
FEEDBACK, AS A PARTICULARLY STRONG BULL`S EYE MOVES INTO FL`S BIG
BEND INTO THE WESTERN SUBTROPICAL ATLANTIC MIDDAY FRIDAY, WHICH
ACTS TO OPEN UP THE GFS SOLUTION AT THE 500 HPA AND 700 HPA LEVELS
FRIDAY AFTERNOON.  THIS IS LEADING TO A QUICKER SOLUTION AND MORE
DELAYED CLOSURE OF THE 500 HPA AND 700 HPA LOWS.  THE SYSTEM
SHOULD MAINTAIN SOME PROGRESSION DUE TO MOVEMENT UPSTREAM ACROSS
SOUTHWEST/SOUTHERN ROCKIES, BUT THE GFS IS LIKELY TOO QUICK.  TO
ACCOUNT FOR THIS, FAVOR A COMPROMISE OF THE 12Z GFS/00Z ECMWF WITH
CONFIDENCE NO BETTER THAN AVERAGE CONSIDERING THE EXISTING MODEL
SPREAD.


SYSTEM MOVING BY NEW ENGLAND FRI NIGHT/SAT MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  GENERAL MODEL COMPROMISE
CONFIDENCE:  AVERAGE

THERE ARE SLIGHT ISSUES ALOFT WITH THE SYSTEM`S PROGRESSION AND
SHARPNESS, BUT FOR THE MOST PART, THE MASS FIELD ISSUES ARE QUITE
SMALL.  A GENERAL MODEL COMPROMISE IS PREFERRED HERE WITH AVERAGE
CONFIDENCE CONSIDERING THE EXISTING MODEL SPREAD AND ITS
PROGRESSIVE NATURE.



...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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