

939 

AGNT40 KWNM 150112

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

912 PM EDT SUN AUG 14 2016



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

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



THE PRELIM 00Z OPC-NCEP SFC ANALYSIS SHOWS WEAK 1010 MB LOW PRES

NEAR THE MAINE COAST. THIS LOW WILL MOVE E TONITE INTO MON. AN

ASSOC COLD FRONT EXTENDS SW FROM THE LOW OVR COASTAL NEW ENGLAND.

THE FRONT WILL PUSH SE OVR THE NT1 WTRS TONITE INTO MON...AND

THEN STALL LTR MON AND MON NITE OVR THE FAR SRN NT1 WTRS. THE

LATEST SATELLITE IMAGERY AND LIGHTNING DATA INDICATES SCTD TSTMS

NR AND AHEAD OF THE COLD FRONT EXTENDING FROM COASTAL NEW ENGLAND

SW TO THE NRN MID ATLC STATES. SCTD TSTMS MAY IMPACT NT1 AND NW

NT2 WTRS IN ASSOC WITH THE FRONT TONITE...AND POTENTIALLY INTO

MON AS WELL. ADTL SCTD TSTMS ARE NOTED OVR THE SW NT2 WTRS...OFF

THE GEORGIA AND SRN S CAROLINA COASTS. THIS ACTIVITY IS MOVG NW.

LOCAL WIND GUSTS EXCEEDING 35 KT AND VERY ROUGH SEAS CAN BE FOUND

IN OR NR ANY OF THE HEAVIER TSTMS TONITE INTO MON. OVERALL...WE

WILL NOT MAKE SIGNIFICANT CHANGES TO THE PREV OPC FCST FOR THE

EVE UPDATE...WITH MINOR TWEAKS TO FIT THE ONGOING FCST WITH

CURRENT WX AND WINDS OCCURRING OVR THE REGION EARLY TONITE.



SEAS...SEAS HEIGHTS RANGE FROM 2 TO 5 FT OVR THE OFF WTRS PER THE

LATEST OBS AND 00Z RA1 SEA STATE ANALYSIS GRAPHIC. LITTLE CHANGE

APPEARS NEEDED TO THE PREV FCST FOR THE EVE UPDATE.



-----------------------------------------------------------------

PREVIOUS DISCUSSION...



SUMMARY...12Z NCEP SFC ANALYSIS SHOWS A WARM FRONT EXTNDG ROUGHLY

W TO E ACROSS THE GULF OF MAINE...WITH A LOW PRES TROF JUST INLAND

OF THE MID ATLC COAST...AND A HIGH PRES RIDGE OVER THE SRN AND

CENTRAL NT2 WTRS. LATEST AVAILABLE ASCAT HI-RES AND ASCAT PASSES

FROM LAST NITE SHOW A COUPLE OF AREAS OF WINDS TO 20 KT IN SW FLOW

OVER THE NRN AND NE PARTS OF THE NT2 WTRS...WITH LIGHT WINDS OF

15 KT OR LESS OVER THE REMAINING OFSHR WTRS. LIGHTNING DENSITY

PRODUCT DATA AT 1830Z DID NOT SHOW ANY SHOWER OR TSTM ACTIVITY

OVER THE OFSHR WTRS.



MAIN WEATHER FEATURES...A WEAK LOW WILL MOVE SE TODAY...PASS JUST

N OF THE NT1 AREA THIS EVENING...THEN ACCELERATE OFF TO THE E

TONITE AND MON. THE LOW WILL PULL A COLD FRONT SE OVER THE NT1 AND

NRN NT2 WTRS TONITE AND MON. A HI PRES RIDGE WILL BUILD OVER THE

NT1 WTRS LATE MON AND MON NITE...THEN MOVE E ACROSS THE NT1 AREA

TUE. ANOTHER LOW WILL PASS E OVER THE NRN NT1 WTRS TUE NITE INTO

WED...THEN ACCELERATE OFF TO THE E LATE WED AND WED NITE. A LOW

PRES TROF WILL APPROACH THE COAST WED NITE...THEN MOVE OFSHR INTO

THE NT1 AND NRN NT2 WTRS THU. ANOTHER COLD FRONT IS EXPECTED TO

MOVE SE OVER THE NT1 AND NRN NT2 WTRS THU NITE AND FRI. 



MODELS...THE 12Z MED RNG MDLS ARE IN VERY GOOD OVERALL AGREEMNT

ACROSS THE OFSHR WTRS DURING THE FCST PERIOD...EXCEPT THE 12Z GFS

IS STILL SIGNIFICANTLY SLOWER THAN THE OTHER MDLS WITH THE SECOND

LOW FOR TUE NITE INTO THU. THE 12Z ECMWF/UKMET MDLS ARE STILL IN

THE BEST AGREEMNT OF ALL THE MED RNG MDLS. THE ECMWF STILL LOOKS

LIKE THE MOST REPRESENTATIVE AND CONSISTENT OF THE MDLS...SO THE

12Z ECMWF SOLN WILL BE USED FOR THE WIND GRIDS OVER THE ENTIRE

FCST PERIOD. 



SEAS...THE 12Z RA1 SEA STATE ANALYSIS INDICATES OBSERVED SEA HTS

CONTINUE TO MATCH UP WELL WITH THE 12Z WNA WAVEWATCH III AND 12Z

ECMWF WAM. IN ORDER TO STAY CONSISTENT WITH THE PREFERRED 12Z ECMWF

SOLN...AM GOING TO USE THE 12Z ECMWF WAM FOR THE WAVE HT GRIDS FOR

THE ENTIRE FCST PERIOD.



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





.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER MILLS/SCOVIL. OCEAN PREDICTION CENTER.

