Prognostic Meteorological Discussion
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000
FXUS10 KWNH 241615
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1215 PM EDT SAT JUN 24 2017

VALID JUN 24/1200 UTC THRU JUN 28/0000 UTC

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

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


...LONGWAVE TROUGH DIGGING ACROSS THE CENTRAL/EASTERN U.S....
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

MULTIPLE SHORTWAVE IMPULSES MOVING ACROSS THE MIDWEST AND DOWN
ACROSS THE GREAT LAKES AND NORTHEAST WILL ALLOW A LONGER WAVE
TROUGH TO EVOLVE OVER THE CENTRAL/EASTERN U.S. THIS WEEKEND AND
THEN GRADUALLY FOCUSING MORE TOWARD THE EAST COAST BY MON/TUES AS
THE LAST IN A SERIES OF SHORTWAVE TROUGHS PIVOTS DOWN ACROSS THE
LOWER GREAT LAKES/OH VALLEY REGION. THE MODELS ARE IN VERY GOOD
MASS FIELD AGREEMENT THROUGH SUN...BUT BY MON AND TUES THE 00Z
UKMET BECOMES THE FASTEST SOLUTION TO ADVANCE THE LONGWAVE TROUGH
TOWARD THE EAST COAST. THE 00Z CMC BECOMES THE SLOWEST AND DEEPEST
SOLUTION. THE 12Z NAM/12Z GFS AND 00Z ECMWF ARE ALL IN BETWEEN
WITH THEIR TIMING...WITH THE NAM AND GFS THE FASTER SOLUTIONS OUT
OF THIS GROUP. THE NAM THOUGH IS SEEN AS BEING PERHAPS A LITTLE
TOO SHARP WITH ENERGY IT HAS DIGGING DOWN ACROSS THE OH VALLEY AND
CENTRAL APPALACHIANS...AND SO AT THIS POINT...WILL COMPROMISE
BETWEEN THE GFS AND ECMWF.


...UPPER LOW MOVING INTO BRITISH COLUMBIA BY MON...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: ABOVE AVERAGE

ALL OF THE MODELS INDICATE AN UPPER LOW EXITING THE GULF OF AK AND
MOVING INTO BRITISH COLUMBIA BY MON WITH A SOUTHWARD EXTENSION OF
A TROUGH AXIS IMPACTING THE PACIFIC NORTHWEST. BY TUES...THIS
ENERGY WILL MOVE EAST ACROSS ALBERTA AND OVER THE NORTHERN HIGH
PLAINS. THE 12Z NAM IS A STRONGER OUTLIER SOLUTION WITH THIS
SYSTEM. WILL PREFER THE WELL CLUSTERED GLOBAL MODELS...WHICH
EQUATES TO A NON-NAM CONSENSUS.


...DAMPENING UPPER LOW APPROACHING NORTHERN CA/OR BY MON...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PREFERENCE: NON-CMC CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE GUIDANCE BRINGS AN UPPER LOW NORTH OUT OF THE SUBTROPICS THIS
WEEKEND OFFSHORE THE WEST COAST AND THEN ADVANCES IT NORTHEAST IN
A RAPIDLY WEAKENING FASHION TOWARD NORTHERN CA/OR BY MON. THE
SYSTEM SHOULD ARRIVE AS AN OPEN WAVE AND SHEAR INLAND THROUGH TUES
ACROSS THE GREAT BASIN. THE 00Z CMC BECOMES PERHAPS A LITTLE TOO
WEAK WITH THE ENERGY AS INITIALLY ARRIVES ALONG THE WEST COAST AND
MOVES INLAND. WILL PREFER A NON-CMC CONSENSUS GIVEN THE GOOD
CLUSTERING SEEN WITH THE REMAINING GUIDANCE.


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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