Prognostic Meteorological Discussion
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000
FXUS10 KWNH 060648
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
147 AM EST FRI MAR 06 2015

VALID MAR 06/0000 UTC THRU MAR 09/1200 UTC

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

...AN EVALUATION OF THE 00Z MODEL GUIDANCE 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.


...STRONG HEIGHT FALLS EXITING NEW ENGLAND EARLY FRIDAY MORNING...
...FRONTAL ZONE CROSSING THE SOUTHEASTERN U.S...

FINAL PREFERENCE: A NON-00Z CMC SOLUTION
FORECAST CONFIDENCE: ABOVE AVERAGE

A STRONG BAND OF HEIGHT FALLS ARE SEEN ON WATER VAPOR IMAGERY
MOVING EAST OF THE I-95 CORRIDOR. THE ENHANCED MOISTURE PLUME
ADVANCING AHEAD OF THIS UPPER TROF ARE CURRENTLY CROSSING THE
COASTAL CAROLINAS WHICH HAS GENERALLY BROUGHT AN END TO WIDESPREAD
PRECIPITATION ACROSS THE REGION. AS WAS THE CASE YESTERDAY...THE
00Z CMC WAS A LITTLE MORE AGGRESSIVE WITH THE EXTENT OF SURFACE
LOW PRESSURE OFFSHORE OF THE SOUTHEASTERN STATES. OTHERWISE...NO
MAJOR ISSUES ARE NOTED. WITH THAT SAID...WILL FAVOR A NON-00Z CMC
SOLUTION.


...SECONDARY SHORTWAVE MOVING THROUGH THE MID-ATLANTIC ON FRIDAY
NIGHT...

FINAL PREFERENCE: GENERAL MODEL COMPROMISE
FORECAST CONFIDENCE: ABOVE AVERAGE

ON THE WINGS OF THE DEEP UPPER TROF EXITING THE NORTHEASTERN U.S.
WILL BE A LOW AMPLITUDE SYSTEM CURRENTLY MOVING THROUGH THE MIDDLE
MS VALLEY. WITH THE 00Z UKMET TRENDING A TAD SLOWER ACROSS THE
MID-ATLANTIC REGION...THIS BRINGS THE SOLUTION WELL WITHIN THE
MODEL CONSENSUS. THUS...CAN LEAN ON A GENERAL MODEL COMPROMISE
HERE.


...SERIES OF SHORTWAVES RACING THROUGH THE GREAT
LAKES/NORTHEASTERN U.S...
...SURFACE CYCLONE REACHING THE UPPER GREAT LAKES BY SATURDAY
MORNING...

FINAL PREFERENCE: A NON-00Z CMC MODEL COMPROMISE
FORECAST CONFIDENCE: AVERAGE

BROAD CYCLONIC FLOW WILL CONTINUE TO ANCHOR MUCH OF THE
NORTHEASTERN SECTOR OF THE CONTINENT. THIS IS FORECAST TO SPREAD A
SERIES OF SHORTWAVES FROM CENTRAL CANADA DOWN THROUGH THE GREAT
LAKES AND INTO THE NORTHEASTERN U.S. FROM SATURDAY INTO EARLY NEXT
WEEK. THE UPPER FLOW DOES BEGIN TO RELAX AS THE PERIOD PROGRESSES
WHICH SUGGESTS MODERATION IN THE TEMPERATURE PATTERN. AS A
WHOLE...MOST OF THESE SYSTEMS WILL BE RATHER BENIGN IN NATURE
EXCEPT FOR THE INITIAL IMPULSE WHICH CARRIES A MODEST SURFACE LOW
ACROSS THE UPPER GREAT LAKES EARLY SATURDAY. RELATIVE TO THE
GUIDANCE YESTERDAY...THE MODELS ARE CLUSTERING MORE WITH THE
TIMING AND STRENGTH OF THIS CYCLONE. IT APPEARS THE TREND HAS BEEN
IN THE STRONGER DIRECTION AS THE ECMWF SUITE WAS THE ONLY SOLUTION
FAVORING A MORE DEFINED SYSTEM. MORE OF THE UNCERTAINTY LIES WITH
THE PATTERN UPSTREAM AS ADDITIONAL SHORTWAVES MOVE THROUGH THE
NORTHERN TIER. THE 00Z CMC IS SLIGHTLY MORE DEVELOPED WITH A
POTENTIAL SURFACE LOW OVER THE MIDDLE MS VALLEY ON SUNDAY MORNING
WHICH AIDS IN HIGHER QPF AMOUNTS ON DAY 2. ITS SOLUTION CONTINUES
TO REMAIN MORE AGGRESSIVE INTO THE FOLLOWING DAY. OVERALL...WHILE
GENERAL TIMING DIFFERENCES ARE NOTED IN THE PROGRESSIVE NORTHERN
STREAM FLOW...THESE ARE SMALL ENOUGH TO FAVOR A NON-00Z CMC MODEL
COMPROMISE.


...UPPER LOW SPINNING OVER THE NORTHERN GULF OF BAJA CA/SEA OF
CORTEZ...

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

A REX BLOCK WILL BE IN PLACE TO COMMENCE THE PERIOD ACROSS THE
WEST COAST AS A COMPACT UPPER LOW MOVES TOWARD BAJA CA. THE RIDGE
TO THE NORTH SHOULD REMAIN IN ITS POSITION ANCHORING THE CENTRAL
GREAT BASIN WHILE THE CLOSED LOW SLOWLY MOVES TOWARD THE NORTHERN
GULF OF BAJA CA/SEA OF CORTEZ BY LATE FRIDAY. MODELS VARY WITH HOW
QUICKLY THIS FEATURE EVOLVES INTO AN OPEN WAVE MOVING TOWARD FAR
WEST TX. AT THIS TIME...THE 00Z NAM/GEFS MEAN ARE THE QUICKEST
SOLUTIONS WHILE THE 00Z UKMET/21Z SREF MEAN CONTINUE TO BE THE
SLOWEST PLAYERS. IT IS WORTH NOTING THE 00Z ECMWF/CMC TRENDED A
BIT SLOWER. AS THE MODELS CONTINUE TO BE SORTING OUT THE TIMING OF
THIS SYSTEM...THIS TREND APPEARS REASONABLE SO WILL CONTINUE TO
INCORPORATE THE ECMWF/CMC SOLUTIONS INTO THE MIX.


...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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