Prognostic Meteorological Discussion
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FXUS10 KWNH 071833
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
133 PM EST SUN FEB 07 2016

VALID FEB 07/1200 UTC THRU FEB 11/0000 UTC

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

...AN EVALUATION OF THE 12Z MODEL GUIDANCE ALONG WITH FINAL
PREFERENCES/FORECAST CONFIDENCE...

THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


...CLOSED LOW STRENGTHENING OFF THE SOUTHEASTERN U.S. COAST...
...SURFACE CYCLONE DEEPENING ALONG THE GULF STREAM...

FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF/UKMET
FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE

WATER VAPOR IMAGERY THIS AFTERNOON DEPICTED A PRONOUNCED SHORTWAVE
MOVING OFF THE GA/SC COAST WITH LIGHT TO MODERATE RAINFALL WITH
PATCHES OF WINTRY PRECIPITATION AFFECTING THE EASTERN HALVES OF
NC/SC. AT THE SURFACE...A CYCLONE SHOULD CONTINUE TO DEEPEN IN THE
PRESENCE OF A STRENGTHENING UPPER LOW WHILE TRACKING OVER THE GULF
STREAM. THE ENTIRE SYSTEM IS FORECAST TO QUICKLY LIFT TOWARD THE
NORTH-NORTHEAST WITH POTENTIAL IMPACTS OVER SECTIONS OF NEW
ENGLAND BASED ON A RECENT WESTWARD TREND IN MANY OF THE 12Z
MODELS. THIS SHIFT GENERALLY ALIGNS WITH THE LOW TRACKS OF OTHER
MODELS. THE CONSENSUS FORMED SEEMS REASONABLE TO FOLLOW HERE BUT
WILL ADHERE AWAY FROM THE MORE WESTERN SOLUTIONS LATE IN THE
PERIOD WHICH INCLUDE THE 12Z NAM/09Z SREF MEAN. THE WPC PREFERENCE
WILL BE BASED ON THE 12Z GFS/ECMWF/UKMET WITH SUPPORT FROM THE 00Z
ECMWF ENSEMBLE MEAN.


...UPPER TROUGH CURRENTLY CLIPPING NORTHERN ME...

FINAL PREFERENCE: GENERAL MODEL COMPROMISE
FORECAST CONFIDENCE: HIGH

AN ACTIVE NORTHERN STREAM HAS BROUGHT A SHORTWAVE WHICH HAS
SHARPENED OVER EXTREME NORTHERN ME. THIS SYSTEM IS CURRENTLY
EXITING THE CONUS WITH NO DISCERNIBLE DIFFERENCES NOTED. A GENERAL
MODEL COMPROMISE IS WARRANTED HERE.


...BROAD SHORTWAVE DIGGING THROUGH THE UPPER MIDWEST THIS
MORNING...
...EVENTUAL CLOSED LOW MIGRATING FROM THE UPPER GREAT LAKES TO THE
OH VALLEY...
...PAIR OF SURFACE CYCLONES AFFECTING THE GREAT LAKES AND VA
CAPES...RESPECTIVELY...

FINAL PREFERENCE: BLEND OF THE 12Z GFS/GEFS MEAN
FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE

A BROAD UPPER TROUGH MOVING THROUGH THE NORTHERN PLAINS/UPPER
MIDWEST HAS SPREAD LIGHT SNOW TO THE REGION WITH GUSTY WINDS IN
ITS WAKE. ALL OF THIS SHORTWAVE ENERGY WILL TRANSLATE EASTWARD
WITH HEIGHT FALLS SPREADING THROUGH THE OH/TN VALLEYS DOWN INTO
THE SOUTHERN TIER OF THE U.S. COMPARING RECENT GUIDANCE...THE 09Z
SREF MEAN IS A LOT SLOWER IN EJECTING THE TROUGH EASTWARD FROM THE
OH VALLEY TOWARD THE CENTRAL APPALACHIANS ON MONDAY. THIS HAS
IMPACTS ON THE EVENTUAL SURFACE DEVELOPMENT WHICH UNFOLDS IN THE
SOUTHERN MID-ATLANTIC BY 09/0000Z. RECENT ENSEMBLE LOW PLOT
COMPARISONS SHOW THE ECMWF HAS TRENDED SLOWER WITH ONLY A FEW
MEMBERS INDICATING LOW FORMATION BY MONDAY EVENING.
ADDITIONALLY...ITS SOLUTIONS REMAIN SOUTH OF THE CONSENSUS WITH
THE 12Z ECMWF/00Z ECMWF ENSEMBLE MEAN REMAINING A POSSIBLE
SOUTHERN OUTLIER. IT LOOKS LIKE THE GFS SUITE HAS BEEN THE MOST
CONSISTENT AND ALSO RESIDES AT THE CENTER OF THE FORECAST SPREAD.
GIVEN THERE IS STILL SOME UNCERTAINTY IN THE FORECAST...WILL
UTILIZE THE MIDDLE OF THE ROAD SOLUTION WITH A BLEND OF THE 12Z
GFS/GEFS MEAN CONTINUING TO BE FAVORED.


...ELONGATED MID-LEVEL WEAKNESS ACROSS THE SUBTROPICAL EASTERN
PACIFIC INTO MX...

FINAL PREFERENCE: THROUGH 10/0000Z: GENERAL MODEL
COMPROMISE...THEREAFTER: BLEND OF THE 12Z GEFS/00Z ECMWF ENSEMBLE
MEANS
FORECAST CONFIDENCE: HIGH...THEN BECOMING AVERAGE

SOUTH OF THE BUILDING UPPER RIDGE ACROSS THE WESTERN U.S...AN
ELONGATED AXIS OF VORTICITY WILL NOSE EASTWARD ACROSS THE
SUBTROPICAL PACIFIC. GRADUAL ORGANIZATION IS FORECAST AS A WEAK
UPPER LOW FORMS IN THE VICINITY OF THE SOUTHERN EDGE OF THE GULF
OF CA/SEA OF CORTEZ BY 09/1200Z. SOME DIFFERENCES EMERGE BY DAY 3
AS THE SYSTEM DIPS DOWN TOWARD SOUTHERN MX. THE 12Z NAM MOVES TO
THE FASTER SIDE OF THE SPREAD WHILE THE DEEPER 12Z/00Z ECMWF
BECOME A BIT TOO SLOW. HOWEVER...THOUGH DAY 2...ALL SOLUTIONS
CLUSTER WELL WHICH WARRANTS A GENERAL MODEL COMPROMISE.
THEREAFTER...WILL UTILIZE ENSEMBLE MEANS GIVEN THE SPREAD ACROSS
THE SUBTROPICAL LATITUDES OF MX.


...SYSTEMS TRACKING THROUGH THE WESTERN PACIFIC TOWARD BRITISH
COLUMBIA...

FINAL PREFERENCE: GENERAL MODEL COMPROMISE
FORECAST CONFIDENCE: AVERAGE

A STOUT RIDGE REMAINS A MAINSTAY FEATURE FOR MUCH OF THE EARLY TO
MIDDLE PART OF NEXT WEEK. MULTIPLE FEATURES DENT THE WESTERN SIDE
OF THE RIDGE WITH THE SHORTWAVE ENERGY RACING UP TOWARD BRITISH
COLUMBIA. THERE ARE GENERAL TIMING/AMPLITUDE DIFFERENCES BUT THESE
APPEAR TO BE RESTRICTED TO THE OFFSHORE PACIFIC WATERS AND INTO
WESTERN CANADA. WITH THAT BEING SAID...A GENERAL MODEL COMPROMISE
WILL BE RECOMMENDED.


...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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