Prognostic Meteorological Discussion
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000
FXUS10 KWNH 010500
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1259 AM EDT MON MAY 01 2017

VALID MAY 01/0000 UTC THRU MAY 04/1200 UTC

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

00Z MODEL EVALUATION...PRELIMINARY MODEL PREFERENCES/CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...DEEP CLOSED LOW LIFTING FROM THE CENTRAL PLAINS ACROSS THE
GREAT LAKES THROUGH TUES WITH TRAILING COLD FRONT CROSSING THE
EASTERN SEABOARD...

PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE

THE LATEST MODEL GUIDANCE IS IN VERY GOOD AGREEMENT WITH THE MASS
FIELD DETAILS OF THIS SYSTEM OVER THE NEXT COUPLE OF DAYS...SO A
GENERAL MODEL BLEND WILL BE PREFERRED.


...PACIFIC FRONTAL SYSTEM CROSSING THE SOUTHERN CANADIAN
ROCKIES...WITH 700 MB TROUGH/SURFACE REFLECTION THAT MOVES OUT OF
ALBERTA/SASKATCHEWAN ACROSS NORTHERN PLAINS/UPPER MISSISSIPPI
VALLEY MON/TUES...

PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE MODELS REMAIN VERY GOOD AGREEMENT WITH THIS FEATURE...SO A
GENERAL MODEL BLEND WILL AGAIN BE PREFERRED.


...WEAK PACIFIC WAVE ENTERING PACIFIC NORTHWEST LATE MON...
...ENERGY CROSSING THE NORTHERN ROCKIES TUES...
...DIGGING INTO THE CENTRAL/SOUTHERN PLAINS TUE NIGHT/WED...

PREFERENCE: BLEND OF THE 00Z GFS/12Z ECMWF
CONFIDENCE: AVERAGE

A WEAK SHORTWAVE TOPS THE MEAN RIDGE IN THE EASTERN PACIFIC AND
MOVES SOUTHEAST ACROSS THE PACIFIC NORTHWEST AND NORTHERN ROCKIES
MON THROUGH TUES...THEN PROGRESSES INTO THE CENTRAL AND SOUTHERN
PLAINS TUES NIGHT/WED. THERE IS STILL A DECENT AMOUNT OF SPREAD IN
THE 00Z SUITE OF MODELS BY TUES NIGHT AND WED AS THE PATTERN
AMPLIFIES AND THE SYSTEM DEVELOPS. THE GUIDANCE THOUGH IS STRONGLY
SUPPORTING THE IDEA OF A CLOSED LOW DEVELOPING OVER THE GULF COAST
STATES BY WED/THURS ALONG WITH A WELL-DEFINED AREA OF LOW PRESSURE
THAT WILL BE GRADUALLY CROSSING THE LOWER MS/TN VALLEY REGION. THE
00Z NAM BECOMES GRADUALLY THE SLOWEST AND OVERALL THE DEEPEST
SOLUTION. THE 12Z CMC IS BECOMES THE WEAKEST WITH ITS SURFACE
LOW...WHILE THE 12Z UKMET BECOME THE STRONGEST. THE 00Z GFS AND
12Z ECMWF CLUSTER TOGETHER THE BEST AND HAVE A BETTER
REPRESENTATION OF THE MODEL CONSENSUS. THE LATEST GEFS MEAN AND
ECENS MEAN ARE JUST A LITTLE SOUTH OF THE GFS/ECMWF CLUSTER...BUT
BASED ON THE LATEST DETERMINISTIC TRENDS...A BLEND OF THE
GFS/ECMWF WILL SUFFICE FOR NOW.


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

ORRISON

$$




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