Prognostic Meteorological Discussion
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000
FXUS10 KWNH 281858
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 PM EDT SUN AUG 28 2016

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

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

12Z MODEL EVALUATION...INCLUDING FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


UPPER TROUGH CROSSING NEW ENGLAND ON MON
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS SHOW SIMILARLY WITH THIS SYSTEM.


UPPER TROUGH TRACKING ACROSS SOUTHERN CANADA THROUGH MID-WEEK
COLD FRONT CROSSING THE NORTHERN PLAINS/GREAT LAKES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z NAM...12Z GFS AND 12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

WHILE THE CMC HAS TRENDED TOWARD THE PREFERENCE ABOVE REGARDING
THE UPPER TROUGH OVER ONTARIO...THE 12Z CMC REMAINS A BIT FASTER
THAN THE DETERMINISTIC CONSENSUS STARTING ON TUE. BY WED...THE 12Z
UKMET ENDS UP A BIT SLOWER...WITH THE 12Z NAM/GFS/ECMWF FORMING A
GOOD CLUSTER IN THE MIDDLE...CLOSEST TO THE LATEST ENSEMBLE MEANS.


UPPER TROUGH DIGGING SOUTH OFFSHORE BRITISH COLUMBIA BY MON
ENERGY PIVOTING INTO THE WEST COAST BY LATE TUES/WED
LEAD SHORTWAVE CROSSING NORTHERN CA ON TUES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM/GFS/ECMWF BLEND
CONFIDENCE: AVERAGE

MINOR TIMING/STRENGTH DIFFERENCES EXIST WITH THE LATEST SUITE OF
MODELS REGARDING BOTH THE LARGE UPPER LOW SINKING SOUTH OFF OF THE
BRITISH COLUMBIA COASTLINE AND A COMPACT VORTICITY MAX ADVANCING
INTO THE COAST OF NRN CA ON TUE. WHILE THE 12Z GFS HAS BEEN A BIT
SLOWER...THE 12Z UKMET/CMC HAVE SPED UP ENOUGH AGAINST THE
REMAINING MODEL CONSENSUS REGARDING THE COMPACT VORT MAX. THE CORE
OF THE UPPER TROUGH FROM THE ENSEMBLE MEANS IS A BETTER FIT TO THE
12Z NAM/GFS/ECMWF COMPARED TO SOME MINOR DIFFERENCES WITH THE
UKMET AND CMC.


MID-UPPER LEVEL TROUGH OVER THE SOUTHWEST TODAY...WEAKENING TOWARD
  THE PLAINS THROUGH WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/ECMWF/UKMET BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

WHILE THERE IS BROAD AGREEMENT WITH THE EVOLUTION OF THIS
FEATURE...THE 12Z NAM/CMC END UP ON THE STRONGER SIDE OF THE
LATEST GUIDANCE.


LOW PRESSURE APPROACHING THE FL KEYS/STRAITS
MOVING INTO THE GULF OF MEXICO MON/TUES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 12Z NAM CONSENSUS
CONFIDENCE: AVERAGE

THERE IS GENERALLY GOOD AGREEMENT OUTSIDE OF THE 12Z NAM...WHICH
ENDS UP PRODUCING MULTIPLE VORTICITY MAXIMA IN THE VICINITY OF THE
FLORIDA PENINSULA...AND TAKES THE TRACK OF A SURFACE LOW MUCH
FARTHER EAST THAN THE 12Z GFS/ECMWF/UKMET/CMC. THE ENSEMBLE
SCATTER LOW PLOTS SHOW MUCH BETTER AGREEMENT WITH THEIR 00Z/28
CYCLE COMPARED TO PREVIOUS RUNS AND CLUSTER RELATIVELY WELL WITH
THE RATHER TIGHT NON-NAM CONSENSUS. THERE IS A SMALLER CLUSTER OF
LOW PLOTS DEPICTED ON THE ENSEMBLES BETWEEN THE
GFS/ECMWF/UKMET/CMC CONSENSUS AND THE WRN FLORIDA COASTLINE WED
EVENING...BUT THESE ARE NOT IN THE MAJORITY. THERE HAVE BEEN SOME
WAFFLES IN STRENGTH NOTED FROM RUN TO RUN IN THE
ECMWF/UKMET/CMC...WITH THE CMC BEING STRONGEST AT THE MOMENT. IT
IS RECOMMENDED TO KEEP THE STRENGTH TOWARD THE MIDDLE OF THE
NON-12Z NAM CONSENSUS.


WEAK MID LEVEL LOW OVER THE WESTERN GULF INTO EARLY NEXT WEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS...12Z ECMWF...12Z UKMET BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 12Z GFS/ECMWF/UKMET SHOW THE BEST AGREEMENT WITH ONE ANOTHER
DESPITE SOME MINOR DIFFERENCES WITH PLACEMENT OF THE MID-LEVEL
CENTER. RUN TO RUN CONSISTENCY IS ALSO RATHER GOOD IN THESE
MODELS. THE 12Z CMC REMAINS WEAKEST AND THE MOST SOUTH...WHILE THE
12Z NAM DEVELOPS MULTIPLE SMALLER SCALE VORTICITY MAXIMA NOT
DEPICTED IN THE OTHER GUIDANCE OF COMPARABLE STRENGTH TO THE
SYSTEM NEAR THE TEXAS COAST.


MID LEVEL LOW APPROACHING THE SOUTHEAST
TROPICAL DEPRESSION EIGHT TRACKING TOWARD THE MID-ATLANTIC COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/00Z ECMWF ARE CLOSEST TO 15Z NHC ADVISORY

THE 12Z GFS AND 00Z ECMWF SHOW THE BEST AGREEMENT TO THE 15Z NHC
ADVISORY TRACK FOR T.D. EIGHT. THE 12Z ECMWF ADJUSTED WEST A BIT
OF ITS PREVIOUS RUN...AWAY FROM THE NHC TRACK. THE 12Z UKMET/CMC
BOTH REMAIN STRONGER AND CLOSE TO THE COAST WITH THE LOW TRACK.
NHC BRINGS T.D. EIGHT TO WEAK TROPICAL STORM STATUS BY SUN
EVENING. REFER TO THE NHC FOR THE MOST UP TO DATE INFORMATION ON
THIS SYSTEM.

OTTO

...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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