Prognostic Meteorological Discussion
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FXUS10 KWNH 251843
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 PM EDT THU MAY 25 2017

VALID MAY 25/1200 UTC THRU MAY 29/0000 UTC

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

12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


...CLOSED UPPER LOW MOVING FROM THE OHIO VALLEY TO THE MIDDLE
ATLANTIC TODAY AND EXITING NEW ENGLAND FRI...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE

THE LATEST DETERMINISTIC MODELS REMAIN IN GOOD AGREEMENT WITH THE
LARGER SCALE FEATURES OF THIS SYSTEM AS IT MOVES FROM THE OH
VALLEY TODAY TO THE NORTHERN NEW ENGLAND COAST BY LATE FRI.


...UPPER TROUGH TRAILING SOUTHWEST FROM THE CLOSED LOW OVER
SASKATCHEWAN ACROSS THE NORTHERN ROCKIES AND PACIFIC
NORTHWEST...MOVING ACROSS THE CENTRAL GREAT BASIN FRI AND THE
CENTRAL ROCKIES SAT...
...WEAK SURFACE LOW AND FRONTAL BOUNDARY ACROSS THE LOWER/MIDDLE
MS VALLEY SAT NIGHT/SUN...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE

OVER THE LAST COUPLE MODEL CYCLES WE HAVE SEEN A GENERAL TREND
TOWARD BETTER MODEL AGREEMENT...WHICH HAS CONTINUED WITH THE 12Z
MODEL RUNS. IN FACT THE 12Z NAM...12Z GFS...AND THE 12Z NON-NCEP
MODELS HAVE CONVERGED TOWARD A COMMON SOLUTION THROUGH SAT AND NOW
FORM A RATHER TIGHT CLUSTER. THE SHORTWAVE WILL BE SOMEWHAT WEAKER
SAT NIGHT/SUN AS IT MOVES INTO THE CENTRAL/SOUTHERN PLAINS...BUT
IT WILL PLAY A ROLE IN THE FORMATION OF A SURFACE FRONTAL BOUNDARY
THAT WILL LIKELY EXTEND FROM THE SOUTHERN PLAINS ACROSS THE
LOWER/MIDDLE MS VALLEY. EVEN THROUGH SUN THE MID/UPPER LEVEL MODEL
MASS FIELDS ARE FAIRLY SIMILAR...BUT THERE ARE BIGGER DIFFERENCES
WITH THE SURFACE PRESSURE PATTERN AND ESPECIALLY WITH THE QPF
FIELDS. THE 12Z GFS AND 12Z ECMWF SHOW THE PRECIPITATION BAND THE
FURTHEST SOUTH...EXTENDING FROM AROUND THE TX/OK BORDER
EAST-NORTHEAST ACROSS THE LOWER/MIDDLE MS VALLEY AND ALONG THE
BORDER OF THE TN VALLEY/OH VALLEY. THAT FURTHER SOUTH SOLUTION
LOOKS LIKE THE MOST LIKELY SCENARIO AT THIS TIME. THE 12Z UKMET
HAS MOVED TOWARD THIS POSITION...BUT IT STILL A BIT TOO FAR NORTH
AND CONTINUES TO HAVE THE HIGHEST QPF AMOUNTS. THE 12Z NAM AND 12Z
CMC PLACE THE PRECIPITATION A BIT FURTHER NORTH WHICH DOES NOT
LOOK CORRECT. EVEN ACCOUNTING FOR THE QPF DIFFERENCES...A GENERAL
MODEL BLEND SHOULD STILL YIELD A REPRESENTATIVE FORECAST.


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

MCDONNAL

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