Prognostic Meteorological Discussion
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FXUS10 KWNH 230539
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
139 AM EDT TUE MAY 23 2017

VALID MAY 23/0000 UTC THRU MAY 26/1200 UTC

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

00Z MODEL EVALUATION WITH PRELIMINARY PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...SHORTWAVE ENERGY MOVING INTO THE PLAINS AND MS VALLEY TODAY...
...DEEPENING TROUGH AND CLOSED LOW MOVING TOWARDS THE EAST COAST
WED INTO THU...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON NAM BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

OVERALL MODELS HAVE COME INTO ABOVE AVERAGE AGREEMENT WITH THE
EVOLUTION OF THIS TROUGH AND CLOSED LOW AS IT PROGRESSES EAST. THE
0Z NAM STILL STANDS OUT A BIT AS A DEEP OUTLIER WITH THE CLOSED
LOW BY 12Z THURSDAY. MINOR DIFFERENCES EXIST WITHIN THE OTHER
DETERMINISTIC GUIDANCE...BUT NOTHING ELSE STANDS OUT AS A LOWER
PROBABILITY OUTCOME. THUS A NON NAM BLEND SHOULD SUFFICE.


...SUBTLE SHORTWAVE FEATURES AND SOUTHERN BRANCH JET MOVING ACROSS
THE SOUTHEAST TODAY...
...SURFACE LOWS TRAVERSING THE GULF COAST INTO THE SOUTHEAST...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE

WHILE SOME MINOR DIFFERENCES STILL EXIST...MODELS HAVE GENERALLY
CONVERGED ON SIMILAR SOLUTIONS WITH THIS ACTIVITY MOVING ACROSS
THE SOUTHEAST AND MID ATLANTIC. THUS A GENERAL MODEL BLEND SHOULD
WORK FINE.


...UPPER TROUGH MOVING ACROSS THE NORTHWEST THROUGH MID WEEK...
...DEVELOPING LONGWAVE TROUGH OVER THE WEST...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 0Z GFS AND 12Z ECMWF BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A RATHER STRONG UPPER TROUGH IS EXPECTED TO DIG SOUTHEAST ACROSS
THE PACIFIC NORTHWEST TUE/TUE NIGHT FROM THE GULF OF AK. THIS
ENERGY WILL ADVANCE INLAND SLOWLY...CROSS THE NORTHERN ROCKIES WED
AND MOVE INTO THE WESTERN PORTION OF THE NORTHERN PLAINS THU.
ADDITIONAL SHORTWAVE ENERGY IS EXPECTED TO DIVE SOUTH AROUND THE
BASE OF THIS TROUGH INTO THE INTERMOUNTAIN WEST BY LATE THURSDAY.
MODELS ARE INITIALLY IN VERY GOOD AGREEMENT WITH THIS SYSTEM.
HOWEVER THE NAM/UKMET/GEM ALL APPEAR A BIT TOO STRONG AND DEEP
WITH THE ADDITIONAL SHORTWAVE ENERGY THAT MOVES AROUND THE BASE OF
THE TROUGH THURSDAY NIGHT INTO FRIDAY. THE 0Z GFS AND 12Z ECMWF
SEEM TO REPRESENT A MORE LIKELY SOLUTION AT THIS TIME.


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

CHENARD

$$





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