Prognostic Meteorological Discussion
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FXUS10 KWNH 061723
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1222 PM EST SAT FEB 06 2016

VALID FEB 06/1200 UTC THRU FEB 10/0000 UTC

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

...AN EVALUATION OF THE 12Z NAM/GFS ALONG WITH PRELIMINARY
PREFERENCES/FORECAST CONFIDENCE...

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


...UPPER TROUGH DIGGING THROUGH THE NORTHEASTERN GULF OF MX LATE
TONIGHT...
...RAPIDLY DEEPENING SURFACE LOW LIFTING UP THE WESTERN ATLANTIC...

PRELIMINARY PREFERENCE: BLEND OF THE 00Z ECMWF/UKMET
FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE

SPLIT FLOW REMAINS OVER THE CONUS WITH A PRONOUNCED SOUTHERN
STREAM SHORTWAVE CURRENTLY MOVING THROUGH THE LOWER MS VALLEY.
PRECIPITABLE WATER VALUES ARE RATHER LOW ACROSS THE GULF COAST AS
A PREVIOUS FRONTAL PASSAGE SCOURED OUT MUCH OF THE TROPOSPHERIC
MOISTURE. THIS SYSTEM IS FORECAST TO INTENSIFY ACROSS THE
NORTHEASTERN GULF OF MX WHERE A CLOSED LOW DEVELOPS BY SUNDAY
MORNING. ULTIMATELY THIS FORMS A SURFACE LOW OFF THE SOUTHEASTERN
U.S. COAST WHICH IS EXPECTED TO RAPIDLY STRENGTHEN. THE 12Z NAM
BEGINS ON THE FAR WESTERN SIDE OF THE SPREAD PER COMPARISONS WITH
ENSEMBLE LOW PLOTS. THESE LATTER SCATTER DIAGRAMS SHOW DIFFERENT
CAMPS SETTING UP WITH THE 00Z CMC MEMBERS BEING ON THE QUICKER
SIDE WITH A BIT MORE CLUSTERING AMONG THE 00Z GEFS/ECMWF ENSEMBLE
MEMBERS. AS THE SYSTEM ACCELERATES TOWARD THE
NORTH-NORTHEAST...THE 12Z NAM/00Z CMC ARE ON THE WESTERN SIDE OF
THE MODEL SPREAD WITH THE ONLY SUPPORT FROM THE 09Z SREF MEAN.
THROUGHOUT THE PERIOD...THE 00Z ECMWF/UKMET SHOW THE MOST
AGREEMENT TOWARD THE 06Z GEFS/00Z ECMWF ENSEMBLE MEANS. WILL LEAN
IN THE DIRECTION OF THESE SOLUTIONS HERE.


...NORTHERN STREAM FEATURE CLIPPING UPPER NEW ENGLAND EARLY
SUNDAY...

PRELIMINARY PREFERENCE: GENERAL MODEL COMPROMISE
FORECAST CONFIDENCE: ABOVE AVERAGE

AMPLIFICATION TAKES PLACE OVER ONTARIO/QUEBEC WHICH DRAGS WEAK
HEIGHT FALLS THROUGH UPPER SECTIONS OF NEW ENGLAND ON SUNDAY
MORNING. THERE ARE SMALL-SCALE DIFFERENCES WITH THIS EVOLUTION BUT
THESE DO NOT APPEAR TO BE DETRIMENTAL TO THE FORECAST. A GENERAL
MODEL COMPROMISE APPEARS REASONABLE WITH THIS SYSTEM.


...PROGRESSIVE SHORTWAVE TRACKING FROM THE UPPER INTERMOUNTAIN
WEST TO THE GREAT LAKES...
...EVENTUAL DEEP UPPER TROUGH ANCHORING THE EASTERN U.S. ON
MONDAY/TUESDAY...
...ASSOCIATED SURFACE CYCLONES...

PRELIMINARY PREFERENCE: BLEND OF THE 06Z GEFS/00Z ECMWF ENSEMBLE
MEANS
FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE

PROGRESSIVE HEIGHT FALLS MOVING THROUGH THE UPPER INTERMOUNTAIN
WEST WILL EVENTUALLY REACH THE UPPER MIDWEST BY 07/1200Z WITH A
CLOSED LOW EVOLVING DURING THIS PROCESS. THE PATTERN APPEARS TO BE
REASONABLY RESOLVED THROUGH THE WEEKEND WITH ENSEMBLE LOW PLOTS
INDICATING MINIMAL SURFACE CYCLONE SPREAD. THIS SOLUTION IS
CENTERED OVER NORTHERN WI WITH SPREAD GRADUALLY INCREASING AS TIME
MOVES ON. LIKE PRECEDING SYSTEMS...THE TROUGH WILL QUICKLY GAIN
AMPLITUDE OVER THE MIDDLE MS VALLEY WITH THIS SHORTWAVE ENERGY
ADVANCING TOWARD THE OH VALLEY/MID-ATLANTIC REGION. MODEL
UNCERTAINTY CONTINUES TO INCREASE...PARTICULARLY WITH TIMING WITH
THE 00Z GEFS/CMC ENSEMBLE MEMBERS ON THE QUICKER SIDE. MULTI-DAY
TRENDS SHOW THE NOW SLOWER 00Z ECMWF SUITE HAS BEEN TRENDING IN
THE SLOWER DIRECTION IN THE PAST 24 TO 48 HOURS. WHILE THE INITIAL
SURFACE LOW MIGRATES TOWARD THE LOWER GREAT LAKES EARLY NEXT
WEEK...A SECONDARY AXIS OF LOW PRESSURE FORMS OVER THE LOWER
MID-ATLANTIC. THE PAST FEW ENSEMBLE LOW PLOTS SHOW THE ECMWF
ENSEMBLES HAVE SUPPORTED A LOW MOVING ALONG THE VA/NC BORDER ON
MONDAY EVENING. MEANWHILE...OTHER GUIDANCE HAVE RECENTLY TRENDED
NORTHWARD...PARTICULARLY THE 12Z GFS. NOT COMPLETELY SOLD ON ANY
DETERMINISTIC SOLUTION GIVEN THE UNCERTAINTY IN THE PATTERN. WILL
FAVOR A COMBINATION OF THE 06Z GEFS/00Z ECMWF ENSEMBLE MEANS UNTIL
FURTHER 12Z GUIDANCE ARRIVES.


...BROAD MID-LEVEL WEAKNESS EXTENDING OVER THE EASTERN SUBTROPICAL
PACIFIC...

PRELIMINARY PREFERENCE: BLEND OF THE 12Z GFS WITH THE 00Z
ECMWF/UKMET
FORECAST CONFIDENCE: AVERAGE

HEIGHTS WILL QUICKLY BUILD OVER THE WESTERN U.S. SETTING UP AN
IMPRESSIVE 588-DM RIDGE. TO THE SOUTH...MODELS SHOW A BROAD
CYCLONIC CIRCULATION STRETCHING BETWEEN 20N AND 30N ACROSS THE
SUBTROPICAL EASTERN PACIFIC. THIS EXTENSIVE AXIS OF VORTICITY IS
FORECAST TO DRIFT EASTWARD TOWARD THE SOUTHERN GULF OF CA/SEA OF
CORTEZ. THE 12Z NAM/00Z CMC ARE A BIT WEST OF THE CONSENSUS FORMED
BY THE ENSEMBLE MEANS. THE BEST SUPPORT COMES FROM THE 12Z GFS AND
00Z ECMWF/UKMET ALTHOUGH THE 00Z ECMWF SOLUTION MAY BE A TAD TOO
ROBUST. WILL COMBINE THE SOLUTIONS FROM THESE THREE WHICH SHOULD
TEMPER THE STRONGER 00Z ECMWF SOME.


...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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