Prognostic Meteorological Discussion
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000
FXUS10 KWNH 161606
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1106 AM EST MON JAN 16 2017

VALID JAN 16/1200 UTC THRU JAN 20/0000 UTC

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

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

CLOSED LOW REACHING THE SOUTHERN PLAINS MON MORNING
SURFACE LOW TRACKING FROM THE SOUTHERN PLAINS TO THE UPPER MIDWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM AND 00Z ECMWF/UKMET BLEND
CONFIDENCE: AVERAGE

GOES-MOSAIC WV LOOP DENOTES LARGE COMMA HEAD WITH DRY PUNCH IN THE
INNER CORE MOVING THROUGH THE LOWER MO VALLEY ATTM.  THE INNER
CORE OF THE UPPER LOW BEGINS TO FILL WITH TIME BUT TRACK INTO THE
GREAT LAKES UNDER FAIRLY GOOD MODEL AGREEMENT.  THE 12Z GFS LIKES
ITS PRIOR RUN IS A BIT FASTER TO LIFT OUT AND WEAKEN INTO NEW
ENGLAND.  THE 00Z CMC CONTINUES TO LAG THE CONSENSUS.  THE
ECMWF/ECENS MEAN ARE STARK WITH ITS TIMING/STRENGTH AND PLACEMENT
THROUGH THE LAST FEW DAYS AND GIVEN THIS WAS THE PREFERENCE...SEE
NO REASON TO BREAK FROM IT AT THIS POINT.  THE 00Z UKMET AND 12Z
NAM REMAIN QUITE CLOSE TO THE ECMWF/CONSENSUS.   THE 12Z NAM HAS
SOME ISSUES CROSSING INTO NEW ENGLAND LATER IN THE PERIOD MAINLY
DUE TO UPSTREAM DIFFERENCES THIS DOES NOT IMPACT THIS PORTION OF
THE WAVE.  PLEASE SEE SECTION BELOW DESCRIBING THE NEXT WAVE AND
THE TRANSFER TO THE COASTAL SURFACE LOW.  AS SUCH A 12Z NAM AND
00Z UKMET/ECMWF BLEND IS PREFERRED AT AVERAGE CONFIDENCE.


SHORTWAVE CROSSING THE NRN ROCKIES/NRN PLAINS SUN NIGHT/MON
INTERACTION WITH THE SHORT WAVE TRACKING FROM THE SRN PLAINS INTO
THE MIDWEST MON/TUE
SECONDARY SURFACE LOW DEVELOPMENT OFF SOUTHEAST NEW ENGLAND WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z UKMET/ECMWF BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE 12Z NAM SHOWS SOME KNOWN BIAS WITH THIS SHORTWAVE...SUPPORTING
A STRONG CONCENTRIC CENTER THAT DEEPENS SOUTH A BIT TOO MUCH
BECOMING NOTICEABLY SLOWER TRACKING ACROSS SOUTHERN GREAT
LAKES/OHIO RIVER VALLEY LEADING TO A MORE ELONGATED WEAKER AND
FURTHER NORTH SURFACE LOW DEVELOPMENT JUST OFF THE SOUTHEAST NEW
ENGLAND COAST.   THE 12Z GFS WHILE LOOKING MORE PRESENTABLE WITH
THE 00Z/06Z RUNS REDUCING THE HIGHLY AMPLIFIED WAVE CLOSER TO
CONSENSUS KEEPS THE WEAKER WAVE BUT SHOWS SOME TYPICAL GFS FAST
BIAS THROUGH NEW ENGLAND WED.   THE ECMWF/ECENS MEAN CONTINUE
STRONG CONSISTENCY WITH LITTLE INDICATION OF A CHANGE IN
OBSERVATION TO NOT KEEP PREFERRING IT.  THE 00Z UKMET WHILE NOT
IDEALLY LOCKED TO THE ECMWF SOLUTION IS QUITE CLOSE IN
TIMING/STRENGTH AND PLACEMENT OF THE WAVE AND ASSOCIATED SURFACE
LOW TO ADD IT TO THE WPC PREFERENCE OF THE 00Z ECMWF/UKMET.
CONFIDENCE REMAINS SLIGHTLY BELOW AVERAGE.


SOUTHWEST US AND NORTHERN MEXICO UPPER TROUGH MOVING INTO THE
SOUTHERN PLAINS WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z UKMET/ECMWF BLEND
CONFIDENCE: AVERAGE

LINGERING POSITIVE TILT TROF ENERGY ACROSS THE SOUTHWEST/NW MEXICO
BEGINS TO CONSOLIDATE AS IT SLOWLY LUMBERS EAST INTO THE SOUTHERN
HIGH PLAINS WITH A MUCH TIGHTER OVERALL AGREEMENT IN STRENGTH AND
LOCATION NOTED IN THE 00Z CYCLE WITH RESPECT TO THE PRIOR 3/4
DAYS.  THE CONSENSUS HAS GRAVITATED TOWARD THE ECMWF/ECENS
SOLUTION WHICH CONTINUES TO BE A BIT MORE PROGRESSIVE OVERALL THAN
THE REST OF THE DETERMINISTIC GUIDANCE WITH ENOUGH REMAINING
ELONGATION OF THE TROF TO START TAKING A MORE NEGATIVE TILT
APPEARS ACROSS THE RED RIVER/LOWER MS RIVER VALLEY REGION BY THE
END OF DAY 3 AS IT LIFTS NORTHEAST OVERALL.  THE 00Z UKMET IS MOST
IN LINE WITH THE OVERALL SHAPE AND TIMING.  THE 12Z NAM TRENDED
FASTER...EVEN OUTPACING THE ECMWF A BIT BUT TYPICAL OF THE NAM BY
DAY 3 IS MORE CONCENTRIC NOT SHOWING THE SLIGHT ELONGATION TO THE
TROF THAT BECOMES THE MORE PRONOUNCE NEGATIVE TILT OF THE
ECMWF/UKMET.   THE 12Z GFS  CONTINUES TO LAG THE OVERALL PATTERN
ABOUT 3-6 HOURS AND THEREFORE REMAINS WELL WEST OF THE
ECMWF/ENSEMBLE SOLUTIONS.   AS SUCH WILL SUPPORT A 00Z UKMET/ECMWF
BLEND AS PREFERENCE AT THIS TIME AT AVERAGE CONFIDENCE.


SHORTWAVES IN FAST FLOW ACROSS THE PACIFIC NORTHWEST MON/TUE
AMPLIFYING TROUGH REACHING THE WEST COAST WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/00Z ECMWF BLEND
CONFIDENCE: AVERAGE

STRONG/FAST FLOW INTO THE PACIFIC NORTHWEST CONTINUES WITH A FEW
EMBEDDED SHORTWAVE FEATURES BEFORE THE PATTERN BEGINS TO AMPLIFY
WED INTO THURSDAY.   OVERALL TIMING OF THE EMBEDDED SHORTWAVES
SEEMS TO BE COMING INTO BETTER AGREEMENT OVERALL CENTERED AROUND
THE 12Z GFS/00Z ECMWF AND THEIR RESPECTIVE MEANS.  BOTH THE 12Z
NAM AND 00Z UKMET ARE WELL TIMED TO THE GFS/00Z ECMWF BUT ARE BOTH
A BIT MORE AMPLIFIED RESPECTFULLY.   AS THE TROF AMPLIFIES
THURSDAY THE GFS/ECMWF REMAIN IN GOOD AGREEMENT AS THE BULK OF
SHORTWAVE ENERGY DROPS INTO SOUTHERN CALIFORNIA AND LOWER CO RIVER
BASIN BY THE END OF THE FORECAST.   THE 00Z CMC BECOMES MOST OUT
OF PHASE IN GENERAL WITH VERY LITTLE SHAPE TO THE PATTERN.

EVEN THOUGH THERE IS GOOD LARGER SCALE DETAIL TO A GFS/ECMWF BLEND
FOR SOME OVERALL CONFIDENCE THE NUMEROUS SMALL SCALE AND VERY
IMPORTANT EMBEDDED WAVES LEAD TO IMPACTING WX DIFFERENCES FOR ONLY
AVERAGE CONFIDENCE OVERALL IN THIS BLEND.

www.wpc.ncep.noaa.gov/html/model2.shtml...

www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

GALLINA

$$





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