Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 251355
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
955 AM EDT WED 25 MAY 2016

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.

LATEST MODELS ARE IN GOOD AGREEMENT OVER THE NEAR TERM THAT THE
UPPER LEVEL LOW NEAR GEORGES BANK WILL CONTINUE TO WEAKEN AND
MOVE E TODAY. LIGHTNING DENSITY SUGGESTING THAT THE FEW DISCRETE
STRONG TSTM CELLS ACROSS NE NT2 WATERS NEAR 38.5N 67W ARE
WEAKENING SOMEWHAT AND SHOULD MOVE E OF THE WATERS BY 18Z. LAST
NIGHTS MODELS SEEM TO BE COMING INTO A BETTER CONSENSUS WITH A
POSSIBLE EARLY SEASON TROPICAL DEVELOPMENT OFF THE SE COAST
LATER IN THE WEEK AND THIS WEEKEND. NHC INCREASED THE TROPICAL
FORMATION CHANCE THIS MORNING...AND MARINERS SHOULD CLOSELY
MONITOR SUBSEQUENT FORECASTS AND NHC TROPICAL OUTLOOKS OVER NEXT
COUPLE DAYS.

BOTH THE 00Z/06Z WAVEWATCH III AND THE 00Z ECMWF WAM ARE WELL
INITIALIZED WITH W ATLC WAVE HEIGHTS THIS MORNING AND ARE
GENERALLY IN GOOD AGREEMENT OVER THE OFFSHORE WATERS FOR THE
NEXT SEVERAL DAYS. THERE ARE SOME DIFFERENCES OVER THE SOUTHERN
MID ATLC WATERS AS 00Z ECMWF WAM IS 3 TO 4 FT HIGHER THAN 06Z
WW3 FRI AS ECMWF IS STRONGER THAN GFS WITH WINDS ASSOCIATED WITH
DEVELOPING LOW. WAVE HEIGHTS OVER THESE SOUTHERN WATERS WILL
OBVIOUSLY HINGE ON ANY POSSIBLE TROPICAL OR SUBTROPICAL CYCLONE
DEVELOPMENT.

----------------------------------------------------------------
...PREVIOUS DISCUSSION...

SUMMARY...00Z NCEP SFC ANALYSIS SHOWS A LOW PRES CENTER NEAR
MARTHAS VINEYARD...WITH A DISSIPATING OCCLUDED FRONT EXTNDG NE
FROM THE LOW ACROSS THE GULF OF MAINE. A NE TO SW ORIENTED COLD
FRONT WAS ANALYZED E OF THE OFSHR WTRS BUT W OF BERMUDA...WHILE
A HI PRES RIDGE IS SHOWN OVER THE SRN NT2 WTRS. LATEST AVAIL
ASCAT HI-RES AND RAPIDSCAT PASSES FROM EARLIER TONITE SHOW MAX
WINDS IN THE 15 TO 20 KT RANGE ASSOCD WITH THE LOW OVER THE
CENTRAL AND NRN NT2 WTRS. LIGHTNING DENSITY PRODUCT DATA AT
0630Z SHOWS A FEW SMALL AREAS OF SCATTERED SHOWERS AND TSTMS
OVER THE NRN NT2 WTRS S AND E OF 1000 FM...WITH AN AREA OF
SCATTERED SHOWERS IN ZONE 800 OVER THE NRN GULF OF MAINE

MAIN WEATHER FEATURES...THE LOW WILL MOVE NE ACROSS THE GULF OF
MAINE EARLY TODAY WHILE WEAKENING. A COLD FRONT WILL PASS E OVER
THE NT1 AREA LATER TODAY INTO THU. A WARM FRONT WILL LIFT NE
ACROSS THE NT1 WTRS LATE FRI INTO SAT. ANOTHER COLD FRONT WILL
MOVE SE ACROSS THE NT1 AND NE NT2 WTRS SAT INTO SUN. ANOTHER LOW
IS EXPECTED TO FORM OVER THE BLAKE RIDGE AREA FRI NITE OR EARLY
SAT...THEN DRIFT NW TOWARDS THE FAR SW NT2 WTRS SAT NITE THRU
SUN NITE.

MODELS...00Z ECMWF/GFS/UKMET TRACKS THE LOW NW OVER THE SW NT2
WTRS SAT NITE THRU SUN NITE...WHILE THE 00Z GEM IS SIGNIF FASTER
AND TAKES THE LOW INTO THE NT2 WTRS FRI NITE. OTHERWISE THE 00Z
MED RNG MDLS ARE IN GUD AGREEMNT ACROSS THE OFSHR WTRS...WITH
THE 00Z ECMWF/GFS 10M IN BEST AGREEMNT. WILL USE A 50/50 BLEND
OF THE 00Z ECMWF/GFS 10M TO POPULATE THE WIND GRIDS FOR THE
ENTIRE FCST PRD.

SEAS...WNA VERSION OF THE 00Z WAVEWATCH III MDL AND 00Z ECMWF
WAM BOTH INITIALIZED REASONABLY WELL OVER THE OFSHR WTRS. THE
MDLS ARE IN GUD OVERALL AGREEMNT THRU THE FCST PRD...EXCEPT
THERE ARE SOME RELATIVELY MINOR DIFFERENCES OVER THE SRN NT2
WTRS FOR THE FRI THRU SUN NITE TIMEFRAME. IN ORDER TO BE
CONSISTENT WITH PREFERRED ATMOS MDLS AND ALSO TO SMOOTH OUT THE
DIFFERNCES BETWEEN THE WNA WW3 AND ECMWF WAM...A 50/50 BLEND OF
THE 00Z WNA WW3/ECMWF WAM WILL BE USED FOR THE WAVE HT GRIDS FOR
THE ENTIRE FCST PRD.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER CLARK/SCOVIL. OCEAN PREDICTION CENTER.



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