Prognostic Meteorological Discussion
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FXUS10 KWNH 281911
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
310 PM EDT THU JUL 28 2016

VALID JUL 28/1200 UTC THRU AUG 01/0000 UTC

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

12Z FINAL MODEL EVALUATION INCLUDING PREFERENCE AND FORECAST
CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

TUTT ENERGY LIFTING NORTH ACROSS MS VALLEY INTO MID-ATLANTIC/NEW
ENGLAND FRI INTO SAT WITH SURFACE LOW DEVELOPING IN VA/NC PIEDMONT
THUR
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE

SYNOPTICALLY THE MODELS REMAIN IN GOOD AGREEMENT. THE 0Z GEM
REMAINS THE ONLY BIG OUTLIER. UNCERTAINTY STILL EXISTS WITH THE
AXIS OF HIGHEST QPF...DRIVEN IN PART BY CONVECTIVE AND MESOSCALE
PROCESSES. SEE THE QPFPFD FOR MORE DETAILS ON THE QPF ASPECT OF
THIS SYSTEM.

19Z UPDATE: THE 12Z GEM HAS TRENDED MORE IN LINE WITH THE
REMAINDER OF THE GUIDANCE WITH REGARDS THE SHORTWAVE AND LOW TRACK.


MULTIPLE WEAK SHORTWAVES OVERTOPPING SW RIDGE TO CARVE OUT A
BROAD/WEAK TROF ACROSS LOWER MISSOURI RIVER VALLEY FRI AND INTO
THE SOUTHERN GREAT LAKES/OH RIVER VALLEY BY SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 12Z GFS/NAM/ECMWF
CONFIDENCE: AVERAGE

BROAD TROUGHING EXISTS AND WILL CONTINUE TO DEVELOP ACROSS THE
NORTHERN PLAINS INTO THE MS RIVER VALLEY IN THE WAKE OF THE
EXITING CLOSED LOW IN CANADA/TUTT CELL LIFTING NORTHEAST THROUGH
NEW ENGLAND.  THIS PATTERN SUPPORTS NUMEROUS CONVECTIVELY INDUCED
UPSCALE GROWTH SCENARIOS...SOME WITH ADDITIVE EFFECTS...AS WAVES
DROP SOUTHEAST AROUND THE PERIPHERY OF THE SOUTHWESTERN U.S.
RIDGE. THE 0Z GEM/UKMET ARE STRONGER/NORTH WITH A DEVELOPING
SURFACE LOW ACROSS THE GREAT LAKES...OHIO VALLEY AND MID ATLANTIC
REGIONS BY THE WEEKEND. AT THIS TIME THERE IS NOT MUCH SUPPORT FOR
THIS STRONGER SOLUTION. A CONSENSUS OF THE 12Z GFS/NAM AND THE 0Z
ECMWF APPEARS TO REPRESENT THE MOST PROBABLE OUTCOME AT THIS TIME.

19Z UPDATE: THE 12Z GEM/UKMET REMAIN A BIT DEEPER THAN THE ECMWF
AND NCEP GUIDANCE...AND ARE THUS STILL NOT PREFERRED AT THIS TIME.
WHILE MINOR DIFFERENCES EXIST BETWEEN THE ECMWF/GFS/NAM...THE
SOLUTIONS ARE SIMILAR ENOUGH THAT ARE ALL REASONABLE. THUS A BLEND
OF THE THREE SHOULD WORK WITH THIS SYSTEM.


SHORTWAVE TROF DIGGING ACROSS NORTHWEST US BY SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GEM BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A DEVOLVING CLOSED LOW IN THE GULF OF ALASKA IS ELONGATING WITH
NUMEROUS INTERNAL SHORTWAVES NOTED.  AS THE OVERALL PATTERN
SUPPORTS SOUTHEASTWARD TRACKING OF THE ENERGY...THE MODELS ARE IN
GENERAL AGREEMENT WITH THE EVENTUAL INTERACTION OF SHORTER WAVE
FEATURES CONSOLIDATING INTO TWO MORE CONCENTRIC CLOSED LOW(S)
ACROSS WESTERN CANADA AND THE GULF OF ALASKA. MODELS HAVE TRENDED
INTO PRETTY GOOD AGREEMENT WITH THE HANDLING OF THESE UPPER LOWS.
WHILE MINOR DIFFERENCES STILL EXIST WITH THE TIMING AND DEPTH OF
THE WAVES...ONLY THE 0Z GEM REALLY STANDS OUT AS AN OUTLIER AT
THIS TIME. THUS A NON GEM BLEND SHOULD SUFFICE FOR THIS REGION FOR
THE TIME BEING.

CHENARD

...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...

...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

$$




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