

158 

AGNT40 KWNM 071930

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

330 PM EDT SUN AUG 7 2016



.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT

.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.



THE LTST GOES VIS IMGRY INDC A FRONTL BNDRY ACRS THE NRN AND

CENTRAL NT2 WTRS. THE LGTNG DENSITY PROD INDC A FEW SCATTERED

SHOWERS AND TSTMS ALONG THE FRONT...MAINLY IN THE UNSTABLE

ENVIRONMENT OVER THE GULF STREAM. THE PREV FCST GRIDS INDC

SHOWERS AND TSTMS IN NT2 ASSOC WITH THE FRONT AS IT MOVES SLOWLY

S...SO ATTM PLANNING ON MAINTAINING MENTION IN THE NEXT FCST PKG.



OTRW...15Z ASCAT WIND RETRIEVALS INDC UP TO 25 KT IN THE SW FLOW

AHD OF THE FRONTAL BNDRY IN THE UNSTABLE ENVIRONMENT OVER THE

GULF STREAM. THE 12Z GFS WINDS ARE INIT OK WHEN COMPARED WITH THE

DATA...AND INDC 20 KT OVR NT2...WITH 25 KT JUST E OF THE OFSHR

WTRS. THE 12Z MDLS AGREE FAIRLY WELL ON THE TMG AND INTNSTY OF THE

FRONT...AND INDC IT WL SLOWLY WKN WHILE MOVG TO THE SRN NT2 WTRS

AND STALLING NR CAPE HTRS TNGT. THE PREV FCST STAYED NR THE GFS

WITH THIS SYS...AND WITH THE GFS NOT CHANGING MUCH...PLANNING ON

STAYING NR IT FOR THE NEXT FCST WITH THIS SYS. ALSO...THE AREA OF

TSTMS IN THE GULFMEX HAVE STAYED OVER WATERS...AND DECOUPLED FROM

A LOW CTR THAT HAS MOVED INLND OVER NRN FLORIDA. THE 12Z MDLS ALL

INDC THAT THE LOW WL MOVE SLOWLY TO THE W...UNDER AN UPR RDG THAT

IS NOT PROVIDING MUCH IN THE WAY OF STEERING. AS A RESULT...ATTM

NOT XPCTG THIS SYSTEM TO IMPACT THE NT2 WTRS.



THE GFS HAD BEEN A FAST OUTLIER WITH THE NEXT FRONT TO MOVE OFF

THE NEW ENGLAND COAST WED NIGHT INTO THU...AND THE 12Z RUN HAS NOT

SLOWED DOWN MUCH. IN FACT...THE 06Z GFS HAD SLOWED SLIGHTLY...AND

WAS A LITTLE CLOSER TO THE SPEED OF THE 00Z ECMWF/UKMET/GEM SOLNS.

HOWEVER...THE 12Z GFS REVERSED COURSE...AND IS NOW TAKING THE

FRONT OFF THE NEW ENGLAND COAST AT THE SAME SPEED AS THE 00Z

GFS...SO GFS IS AGAIN THE OUTLIER SOLN WITH THIS FRONT...SO CONFDC

IS LOW WITH IT. IN ADDITION...THE 12Z ECWMF/UKMET/GEM ALL DVLP A

WK LOW TO THE E OF THE BAHAMAS...FROM THE AREA OF TSTMS CRNTLY S

OF THE AREA. THE 12Z MDLS ALL KEEP THE LOW FAIRLY WK...BUT THE GFS

IS AGAIN AN OUTLIER SOLN AS IT DOES NOT DVLP THE LOW AT ALL. IN

ADDITION...THE WPC MED RANGE GUID INDC THE LOW ON THE LTST FCST

PROG CHARTS...AND FAVORS THE 12Z ECMWF SOLN...SO ATTM PREFERRING

TO SWITCH TO THE 00Z ECMWF SOLN FOR THE FCST FM ABT 00Z WED

ONWARD.



.SEAS...THE 12Z MULTIGRID WAVEWATCH-III AND ECMWF WAM MDLS ARE

INIT WITHIN A FT OR TWO OF THE CRNT DATA...AND SEEM RSNBL AND

AGREE WELL THRU THE FIRST 48 HOURS OF THE FCST PD. MINOR DIFFS

START APPEARING AFTER THAT PT...MAINLY AS THE RESULT OF THE DIFFS

BTWN THE ASSOC WX MDLS. ATTM PLANNING ON USING THE 12Z INTO 00Z

WED...THEN USING TO THE 12Z ECMWF WAM THEREAFTER TO REFLECT

PREFERRED WX MDL TRENDS.



.EXTRATROPICAL STORM SURGE GUIDANCE...N/A. 



.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER KELLS. OCEAN PREDICTION CENTER.

