Prognostic Meteorological Discussion
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FXUS10 KWNH 281618
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1117 AM EST WED JAN 28 2015

VALID JAN 28/1200 UTC THRU FEB 01/0000 UTC

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

12Z MODEL EVALUATION...INCLUDING THE NAM AND GFS


...SHORTWAVE TROUGHING/ENERGY CROSSING THE CENTRAL
PLAINS/MIDWEST...
...NEGATIVELY TILTING UPPER TROUGH REACHING THE NORTHEAST BY FRI...
...REDEVELOPING COASTAL NEW ENGLAND SURFACE LOW...

PREFERENCE: BLEND OF THE 12Z GFS/00Z ECMWF
CONFIDENCE: AVERAGE

SHORTWAVE ENERGY CURRENTLY SHEARING OUT OF THE GREAT BASIN IS
EXPECTED TO ADVANCE EAST AND CROSS OUT THROUGH THE CENTRAL PLAINS
AND MIDWEST THROUGH THURS. THE MODELS SHOW GOOD AGREEMENT IN
DEPICTING ADDITIONAL NORTHERN STREAM ENERGY DIGGING IN BEHIND THE
LEAD SHORTWAVE...WITH A COMBINATION OF THE TWO LEADING THE WAY FOR
WHAT SHOULD BE A LARGER SCALE AND NEGATIVELY TILTING TROUGH ACROSS
THE GREAT LAKES/OHIO VALLEY AND NORTHEAST THROUGH FRIDAY. THERE IS
GOOD AGREEMENT IN ENOUGH AMPLIFICATION FOR A MID LEVEL LOW TO
CLOSE OFF OVER SOUTHERN NEW ENGLAND BY FRI NIGHT WHICH WILL MOVE
ACROSS THE GULF OF MAINE ON SAT. THE STRONG HEIGHT FALLS WILL
ALLOW SURFACE LOW PRESSURE TRAVERSING THE MIDWEST AND LOWER GREAT
LAKES REGION TO REDEVELOP JUST OFF SOUTHERN NEW ENGLAND BY MIDDAY
FRI AND THEN INTENSIFY OVER THE GULF MAINE.

THERE IS GOOD AGREEMENT AMONG THE MODELS WITH THE LARGER SCALE
EVOLUTION OF THIS NEXT SYSTEM...BUT THERE ARE SOME TIMING
DIFFERENCES TO NOTE. THE 00Z ECMWF AND 00Z GEM ARE A TAD SLOWER
THAN THE 12Z GFS AND 00Z UKMET WITH THE TROUGH EVOLUTION BY FRI
AND SAT OVER THE NORTHEAST. AT THE SURFACE...THE ECMWF AND GEM
ALONG WITH A NUMBER OF THEIR RESPECTIVE ENSEMBLES FOCUS
REDEVELOPING LOW PRESSURE A BIT FARTHER SOUTH THAN THE
DETERMINISTIC GFS AND THE GEFS MEMBERS. THE NAM APPEARS TO SWING
ITS LOW CENTER FARTHER OFFSHORE THAN ANY OTHER DETERMINISTIC
MODEL...AND WHILE THERE ARE SOME ENSEMBLE MEMBERS THAT DO
THIS...THE STRONGER CLUSTERING OF ENSEMBLE MEMBERS WOULD SUGGEST
NOT FAVORING THE NAM. SO...WILL FAVOR A NON-NAM CONSENSUS...LED BY
A BLEND OF THE 12Z GFS AND 00Z ECMWF.


...CLOSED LOW ACROSS THE SOUTHWEST BY THE END OF THE WEEK...

PREFERENCE: BLEND OF THE 12Z GFS/00Z ECMWF
CONFIDENCE: AVERAGE

THERE IS STILL RELATIVELY MINOR SPREAD IN A SOMEWHAT BROAD UPPER
TROUGH MAKING ITS WAY TOWARD THE WEST COAST. BY FRIDAY...THE
MODELS DEPICT A LARGE UPPER LOW WITH A BIT OF A N/S ELONGATION
STRETCHING FROM THE GREAT BASIN SOUTH INTO THE NORTHERN BAJA
PENINSULA. STRONGER MODEL CLUSTERING OVERALL TENDS TO FAVOR A
BLEND OF THE 12Z GFS AND 00Z ECMWF...WHICH IS SUPPORTED BY THE
LATEST GEFS MEAN AND ECENS MEAN.


...SHORTWAVE TROUGH/COLD FRONT DROPPING DOWN ACROSS THE NORTHERN
PLAINS SAT...

PREFERENCE: BLEND OF THE 12Z GFS/00Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS DROP NORTHERN STREAM ENERGY ALONG WITH A COLD FRONT
DOWN INTO THE NORTHERN PLAINS REGION BY SAT. THE 00Z GEM IS A BIT
MORE AMPLIFIED WITH THE TROUGH THAN THE MULTI-MODEL CONSENSUS. THE
STRONGER MODEL CLUSTERING AT THIS POINT WOULD FAVOR A BLEND OF THE
12Z GFS AND 00Z ECMWF.


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

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

ORRISON
$$





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