Prognostic Meteorological Discussion
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FXUS10 KWNH 090701
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 AM EDT WED JUL 09 2014

VALID JUL 09/0000 UTC THRU JUL 12/1200 UTC

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

...AN EVALUATION OF THE 00Z CMC/UKMET/ECMWF ALONG WITH FINAL
PREFERENCES/FORECAST CONFIDENCE...

THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 00Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


...UPPER TROF ANCHORING NORTHEASTERN NORTH AMERICA...
...SURFACE BOUNDARY EXITING THE NORTHEASTERN U.S...

FINAL PREFERENCE: GENERAL MODEL COMPROMISE
FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A DEEP AND ANOMALOUS TROF WILL BE FEATURED ACROSS NORTHEASTERN
NORTH AMERICA FOR MUCH OF THE WEEK. A SERIES OF SHORTWAVES ARE
FORECAST TO TRAVERSE ABOUT THE BASE OF TROF WITH THE MEAN NEGATIVE
ANOMALY SHIFTING EASTWARD IN TIME. THROUGH 48
HOURS...11/0000Z...THE MODELS ARE IN REASONABLE AGREEMENT WITH THE
FORECAST EVOLUTION. FORTUNATELY THE 00Z CMC HAS SHIFTED TOWARD THE
COAST WITH THE SURFACE FRONTAL PLACEMENT WHICH BRINGS IT MORE IN
LINE WITH THE OTHER GUIDANCE. THE OVERALL 500-MB HEIGHT PATTERN
OVER THE NORTHEASTERN U.S. IS NOT TERRIBLY DIFFERENT ACROSS THE
BOARD WITH MORE OF THE UNCERTAINTY WITH THE CORE OF LOWER HEIGHTS
UP IN QUEBEC. WITH THE 00Z CMC MAKING THE APPROPRIATE CHANGES
OFFSHORE OF NEW ENGLAND...WILL FAVOR A GENERAL MODEL COMPROMISE
HERE.


...BROAD UPPER TROF MOVING ACROSS WESTERN/CENTRAL CANADA...
...SHORTWAVE SLIDING THROUGH THE NORTHERN PLAINS/UPPER MIDWEST ON
THURSDAY...

FINAL PREFERENCE: BLEND OF THE 00Z GFS/ECMWF
FORECAST CONFIDENCE: AVERAGE

MODELS DEPICT A SYSTEM EVOLVING OUT OF THE GULF OF AK WITH HEIGHT
FALLS SPREADING INLAND ACROSS WESTERN U.S. BY MID-WEEK. THE
CORRIDOR OF STRONGEST HEIGHT FALLS APPEAR TO BE CONFINED TO CANADA
WITH QUASI-ZONAL FLOW PREVAILING FROM THE PACIFIC NORTHWEST INTO
THE NORTHERN PLAINS. MORE OF THE CONUS FOCUS WILL BE ON A
SHORTWAVE SWINGING THROUGH THE NORTH-CENTRAL U.S. ON THURSDAY
BEFORE MIGRATING INTO THE UPPER GREAT LAKES BY THE FOLLOWING DAY.
AFTER REVIEWING THE 00Z GUIDANCE...THE FLATTER SOLUTIONS OF THE
12Z CMC/UKMET HAVE TRENDED TOWARD MORE AMPLIFICATION IN THE 00Z
CYCLE. THIS HELPS BRING MOST OF THE DETERMINISTIC GUIDANCE MORE IN
LINE WITH THE ENSEMBLE MEANS. THE PREFERENCE FROM EARLIER WILL BE
MAINTAINED HOWEVER AS THEY STILL HANDLE THE NORTHERN STREAM
BETTER.


...WEAK TROF OFFSHORE OF THE WEST COAST LATE IN THE PERIOD...

FINAL PREFERENCE: BLEND OF THE 00Z GEFS/12Z ECMWF ENSEMBLE MEANS
FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE

TOWARD THE END OF THE WORK WEEK AND INTO THE EARLY PORTION OF THE
UPCOMING WEEKEND...THE GUIDANCE SHOWS AN ELONGATED UPPER TROF
SITTING JUST OFFSHORE OF THE WESTERN U.S. ALL OF THE 00Z GUIDANCE
NOW SHOW TWO DISTINCT SHORTWAVE FEATURES ALTHOUGH EACH MODEL
VARIES WITH THE PLACEMENT. THE 00Z NAM/GFS ARE FARTHER TOWARD THE
EAST WHICH AGREES CLOSELY WITH THE 00Z GEFS/21Z SREF MEANS.
MEANWHILE...ANOTHER CAMP SETS UP TOWARD THE WEST WHICH IS MORE IN
LINE WITH THE 12Z ECMWF ENSEMBLE MEAN. AS THE MODELS CONTINUE TO
WAVER WITH THEIR SOLUTIONS...WILL IT WOULD BE BEST TO BLEND THE
ENSEMBLE MEANS UNTIL THE FINER DETAILS IRON THEMSELVES OUT.


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

RUBIN-OSTER

$$





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