Prognostic Meteorological Discussion
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000
FXUS10 KWNH 280450
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1250 AM EDT THU JUL 28 2016

VALID JUL 28/0000 UTC THRU JUL 31/1200 UTC

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

00Z 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: 00Z GFS AND 12Z ECMWF/CMC BLEND
CONFIDENCE: AVERAGE

COMPLEX EVOLUTION PATTERN FOR THE EASTERN US WILL CONTINUE IN THE
SHORT TERM LIKELY DRIVEN BY SMALL STORM SCALE CONVECTIVE
INTERACTIONS FEEDING INTO THE LARGER SCALE.  THE TUTT CELL
CURRENTLY THE CENTRAL MS VALLEY WILL CONTINUE TO SHIFT EASTWARD
WITH AN ELONGATED CONFLUENCE ZONE PRECEDING IT INTO THE
MID-ATLANTIC/NEW ENGLAND BY THE LATE WEEK/EARLY WEEKEND...WITH A
DEVELOPING SURFACE REFLECTION TRANSLATING UP THE COAST AS WELL.

THE 12Z NAM HAS TRENDED A BIT FASTER AND THOUGH THE MAIN TUTT
CENTER REMAINS STRONG/CONSOLIDATED IT DOES APPEAR TO BE QUITE FAST
PARTICULARLY TOWARD THE SURFACE BY THE LATTER PORTION OF THE
FORECAST PERIOD.   LIKEWISE THE 00Z GFS IS FAST BUT UNLIKE THE NAM
IS MORE STRUNG OUT/SHEARED THROUGH THE ENTIRE SHEAR AXIS INTO NEW
ENGLAND AND RESPONDING WITH THE WEAKEST SURFACE LOW (MINUS THE
UKMET).  THE GFS HAS TRENDED A BIT SLOWER TOWARD A BETTER MIDDLE
GROUND THOUGH AS IT IS APT TO DO WHEN CONSOLIDATING ON A SOLUTION
WITH THE OTHER DETERMINISTIC PARTNERS (PARTICULARLY THE
SLOWER/DEEPER ECMWF SOLUTIONS).  THIS IS THE CASE WITH THE 12Z
ECMWF...BEING A BIT STRONGER/SLOWER WITH THE WAVE...BUT ON TRACK
WITH THE 18Z GEFS/12Z ECENS MEAN.   THE 12Z UKMET APPEARS TO SHOW
SIMILARITIES TO THE ECMWF/GFS BUT LOOKS DISTINCTLY DIFFERENT AT
THE SURFACE WITH MULTIPLE WEAKER SURFACE REFLECTIONS ALONG THE
FRONTAL ZONE...AWAY FROM BETTER CONSENSUS OTHERWISE.   THE 12Z CMC
MAY BE THE BEST MIDDLE-GROUND SOLUTION OVERALL THOUGH IT HAS SOME
ISSUES IN EVOLUTION AS WELL.  AS A COMPROMISE A BLEND OF THE 00Z
GFS AND 12Z ECMWF/CMC MAY BE BEST MIDDLE GROUND AND MATCH THE
ENSEMBLE SUITE.  CONFIDENCE IN THIS BLEND IS AVERAGE IN THIS BLEND
GIVEN THE COMPLEXITY/MOVING PARTS AND INTER-SCALE INTERACTIONS
THAT WILL PLAY SUCH A KEY ROLE.


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 00Z GFS/12Z 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 ALONG THE
NORTHEAST QUADRANT OF THE ENTRENCHED SOUTHWEST RIDGE.  THIS
PATTERN SUPPORTS NUMEROUS CONVECTIVELY INDUCED UPSCALE GROWTH
SCENARIOS...SOME WITH ADDITIVE EFFECTS.  THIS IS SUGGESTED BY BOTH
THE 12Z UKMET/CMC WHICH HELP TO CONSOLIDATE A DEEPER VORT
CENTER/CLOSED LOW DEVELOPING ACROSS THE GREAT LAKES BY SUN.  THE
00Z NAM IS ALSO SUGGESTIVE OF A DEEPER SOLUTION AS IT IS APT TO
DO...BUT DOES NOT GO AS FAR AS THE UKMET/CMC WEAKENING CONFIDENCE
IN THEIR SOLUTIONS.  THE 12Z GFS IS WEAKEST OF THE DETERMINISTIC
SUITE AND GENERALLY FASTER IN SHIFTING THE TROF EASTWARD THROUGH
THE GREAT LAKES; ESPECIALLY COMPARED TO A SLIGHTLY DEEPER/SLOWER
ECMWF.  AS SUCH WILL FAVOR THIS BLEND OF THE 12Z ECMWF/00Z
GFS...GIVEN SOLID SUPPORT FROM THE ENSEMBLE MEANS AND TRENDS AS
WELL.  CONFIDENCE IN THIS BLEND IS AVERAGE GIVEN THE COMPLEXITY
AND CONVECTIVE INTERACTIONS THAT WILL PLAY SUCH A KEY ROLE.


SHORTWAVE TROF DIGGING ACROSS NORTHWEST US BY SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-ECMWF BLEND
CONFIDENCE: 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.  THE 12Z ECMWF HAS
BECOME DISTINCTLY DIFFERENT THAN THE REST OF THE GUIDANCE AND
THOUGH SUPPORTED BY OTHER 12Z ECENS MEMBERS...IT QUITE AGGRESSIVE
WITH A STRONG/DEEPER TROF DIGGING INTO WA/NORTHERN ROCKIES SAT
NIGHT TO SUNDAY.  THIS IS LIKELY IN RESPONSE TO A LARGER
SPREAD/SPACING WITH THE UPSTREAM SHORTWAVE...BEING WEAKER AND LESS
INFLUENTIAL ON THIS DIGGING TROF.

THE 12Z CMC IS OPPOSITE THE ECMWF...FAVORING THE WESTERN WAVE
ALLOWING FOR THE LEAD WAVE TO BE SHALLOWER AND MORE PROGRESSIVE
ACROSS W CANADA WITH LITTLE INFLUENCE INTO THE US.  THE 00Z
NAM/GFS ARE BOTH A BIT MORE CONSOLIDATED WITH BOTH FEATURES BUT
ALSO GENERALLY SLOWER THOUGH THE GFS IS A BIT FASTER/SOUTH WITH HE
LEAD WAVE THAN THE NAM... THEY ARE BOTH SUPPORTIVE OF THE CMC AND
UKMET EVEN THOUGH BOTH ARE A BIT FASTER.

GIVEN CONTINUITY AND DISPARITY WILL FAVOR A NON-ECMWF BLEND AT
THIS TIME. HOWEVER...CONFIDENCE IS REDUCED AS IT IS TYPICAL OF THE
ECMWF TO LEAD A TREND OUT OF THE PACIFIC NORTHWEST THAT EVENTUALLY
COMES TO FRUITION.  HOWEVER...IT IS USUALLY A BIT CONSISTENT RUN
TO RUN THAN CURRENTLY DENOTED WHEN PROPERLY TRENDING.  AS SUCH
CONFIDENCE IN A NON-ECMWF BLEND IS AVERAGE AT TIME.

GALLINA

...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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