Prognostic Meteorological Discussion
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FXUS10 KWNH 271848
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
248 PM EDT WED AUG 27 2014

VALID AUG 27/1200 UTC THRU AUG 31/0000 UTC

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


FINAL 12Z MODEL EVALUATION

...UPPER TROUGH AND ASSOCIATED COLD FRONT CROSSING THE NORTHEAST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

OVERALL...THE 12Z GUIDANCE IS IN GOOD AGREEMENT WITH RESPECT TO
THE TIMING/AMPLITUDE OF THE 500 MB TROUGH AND ASSOCIATED SURFACE
FRONT.

...UPPER-LEVEL TROUGH/LOW MOVING FROM THE ROCKIES IN THE PLAINS...
...SURFACE COLD FRONT DEVELOPING LATE WED IN THE LEE OF THE
CENTRAL ROCKIES...
...SURFACE LOW LIFTING INTO THE MIDWEST...

PREFERENCE: NON-UKMET COMPROMISE
CONFIDENCE: AVERAGE

OVERALL THE 12Z GUIDANCE IS IN GOOD AGREEMENT WITH THE
AFOREMENTIONED FEATURES UNTIL SAT MORNING WHEN THE UKMET BECOMES
AN AMPLIFIED OUTLIER BOTH WITH RESPECT TO THE UPPER SHORTWAVE/LOW
AND SURFACE LOW MOVING ACROSS THE UPPER MS VALLEY INTO THE GREAT
LAKES REGION.

...SHORTWAVE IMPULSE MOVING FROM THE PAC NW FRI MORNING TO THE
UPPER MIDWEST BY SAT EVENING...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: BELOW AVERAGE

MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THIS FEATURE WITH SOME
MINOR TIMING/AMPLITUDE DIFFERENCES NEAR THE END OF THE PERIOD.

...EASTERLY WAVE ADVANCING WEST ALONG THE GULF COAST...

PREFERENCE: NON-NAM/UKMET COMPROMISE
CONFIDENCE: AVERAGE

AS NOTED IN PREVIOUS RUNS...THE NAM IS MORE AMPLIFIED THAN THE
MAJORITY OF THE MODELS AS THIS SYSTEM MOVES INTO SOUTH TX/NORTHERN
MEX.  THE UKMET IS MORE AMPLIFIED AS WELL...MAINTAINING A
MORE-DEFINED UPPER FEATURE ALONG THE LOWER TX COAST INTO THE
WEEKEND.

...WAVE LIFTING FROM THE CENTRAL GULF INTO THE LOWER MS VALLEY...

PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: AVERAGE

WHILE THERE ARE SOME RELATIVELY SMALL DIFFERENCES WITH RESPECT TO
TIMING/AMPLITUDE...MOST OF THE 12Z MODELS CARRY A WAVE NORTHWARD
FROM THE CENTRAL GULF INTO THE CENTRAL GULF COAST/LOWER MS VALLEY
REGIONS LATE IN THE PERIOD.  THE NAM...WHICH IS MUCH WEAKER THAN
MOST OF THE GUIDANCE MIGHT BE CONSIDERED THE LONE OUTLIER.

...DEEP TROUGH DIGGING INTO THE NORTHWEST BY FRI AND SAT...
...COLD FRONT PUSHING THROUGH THE NORTHWEST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

THERE ARE NO SIGNIFICANT OUTLIERS AMONGST THE 12Z GUIDANCE WITH
THESE FEATURES.

...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

PEREIRA



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