Marine Interpretation Message
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AGNT40 KWNM 231403
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
1003 AM EDT SAT JUL 23 2016

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

AT 12Z A LOW PRES TROUGH WAS EXITING THE NEW ENGLAND/MID-ATLANTIC
COAST...W/THE SRN END OF THE TROUGH STILL INLAND OVER THE SE US. A
0959Z RAPIDSCAT PASS INDICATED 10-25 KT WINDS OVER THE NT1 WATERS
AND NRN HALF OF THE NT2 WATERS. LOOKING AT SATELLITE/LIGHTENING
DATA APPEARS RAPIDSCAT PICKED UP AREAS OF INCREASED WINDS
ASSOCIATED W/THUNDERSTORMS...HENCE PRIOR MENTION OF LOCAL WINDS
ABOVE GALE FORCE FROM CONVECTION AS STATED IN THE PREVIOUS MIM
SEEMED TO VERIFY NICELY. MAIN CONCERN IN THE NEAR TERM WILL
CONTINUE TO BE CONVECTIVE ACTIVITY OVER THE ERN NT1
WATERS...MOVING INTO PARTS OF THE NRN NT2 WATERS PER LATEST
SATELLITE/LIGHTENING DATA. AGAIN BASED ON THE RAPIDSCAT DATA LOCAL
WIND GUSTS EXCEEDING GALE FORCE WILL REMAIN POSSIBLE IN AND NEAR
THUNDERSTORM ACTIVITY. PER SREF THUNDERSTORM PROBS AND SIM REF
FROM 06Z NAM4KM AND LATEST HRRR CONTINUE TO ANTICIPATE
THUNDERSTORM ACTIVITY THROUGH TODAY IN PARTS OF THE NT1/NRN NT2
WATERS AS THE LOW PRES TROUGH MOVES E ACROSS THE WAREA. WILL
ADJUST WEATHER GRIDS AS NEEDED. CONCERNING WINDS WILL ADJUST
INITIAL GRIDS SOME BASED ON INFO FROM 0959Z RAPIDSCAT HIRES PASS
AND AVAILABLE 12Z OBS...OTHERWISE WILL NOT MAKE SIGNIFICANT
CHANGES TO THE REST OF THE GRIDS IN THIS INTERMEDIATE UPDATE GIVEN
06Z GFS/NAM WERE IN GOOD AGREEMENT W/PRIOR 00Z MODEL GUIDANCE.

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

SHORT TERM...THE MAIN CONCERN OVR THE SHORT TERM PORTION OF THE
FCST WILL BE THE LOCALLY VERY GUSTY WINDS AND VERY ROUGH SEAS IN
OR NEAR HEAVY TSTMS CURRENTLY SHOWN BY THE LATEST RADAR...
SATELLITE...AND LIGHTNING DATA IMAGERY...MOVG E AND SE OFF THE
NEW ENGLAND COAST. LOCAL WIND GUSTS EXCEEDING GALE FORCE ARE LKLY
IN AND NR TSTMS. THE STRONGER STORMS ARE CURRENTLY LOCATED NEAR
AND E AND SE OF CAPE COD TOWARD GEORGES BANK...WITH ADTL STRONG
STORMS NEAR THE MAINE COAST. THE LATEST SREF TSTMS GUIDANCE
INDICATES THAT THE BEST CHANCE FOR TSTMS WILL BE OVER MAINLY ERN
AND NRN SECTIONS OF NT1 WTRS INTO MID MORNING...WITH THE TSTMS
THEN POTENTIALLY REACHING NRN AND NE NT2 WTRS BY LATER THIS
MORNING AND AFTN. OTW...A SLOW MOVG COLD FRONT EXTENDS FROM MAINE
W-SW TO THE GRT LKS...WITH A PRE-FRONTAL TROF NOTED FROM NR LONG
ISLAND SW TOWARD SOUTH CAROLINA PER THE PRELIM 06Z NCEP-OPC SFC
ANALYSIS. THE 00Z GLBL MDLS ARE IN VRY GOOD AGREEMENT OVR THE
REGION FOR THE NEXT FEW DAYS. FOR THE EARLY AM PACKAGE WE WILL USE
A 50-50 BLEND OF THE PREV FCST AND THE 00Z GFS 10M WINDS FOR TODAY
THRU MON. THIS WILL HELP TO MAINTAIN FCST CONTINUITY OVR THE WTRS
FOR THE NEXT FEW DAYS. A WEAK COLD FRONT IS STILL FCST TO CROSS
NT1 WTRS TODAY INTO TONITE...AND THEN BECOME STNRY OVR NRN NT2
WTRS EARLY SUN. THE FRONT WILL THEN LKLY DSIPT SUN EVE AND NITE.
WEAK HIGH PRES WILL CROSS NT1 WTRS BEHIND THE FRONT LTR SUN...
AND SLIDE E OF THE WTRS MON AHEAD OF THE NEXT FRONT. ANOTHER WEAK
HIGH PRES RIDGE WILL PERSIST OVR SRN NT2 WTRS INTO TONITE BEFORE
SHIFTING E OF THE AREA SUN THRU MON.

LONG TERM...THE 00Z MDLS REMAIN IN VERY GOOD AGREEMENT OVR THE OFF
WTRS MON NITE THRU WED NITE. WE WILL ONCE AGAIN USE A 50-50 BLEND
OF THE PREV OPC FCST AND 00Z GFS 10M WINDS FOR THE LONG TERM PART
OF THE FCST. THIS WILL RESULT IN LITTLE SIG CHANGE FROM THE PAST
FEW FCSTS FOR THE EARLY AM PACKAGE. THE NEXT COLD FRONT WILL
APPROACH THE NT1 WTRS FROM THE NW MON NITE...THEN PUSH E AND SE
OVR THE WTRS TUE INTO TUE NITE...STALL AND WEAKEN OVR THE SRN WTRS
WED AND THEN LKLY DSIPT WED NITE. THERE WILL BE AN INCREASED
THREAT FOR TSTMS NR AND AHEAD OF THE NEXT COLD FRONT MON NITE INTO
WED MAINLY OVR NT1 AND PERHAPS NRN NT2 WTRS.

SEAS...THE LATEST OBS INDICATE THAT THE 00Z WNA WW3 AND ECMWF WAM
MDLS ARE RUNNING 1-2 FT TOO HIGH OVR MAINLY NT1 OFF WTRS. MAX SEA
HEIGHTS NR 7FT ARE NOTED S AND SE OF LONG ISLAND WITH SEAS TO 8 FT
OVR ERN NT1 WTRS PER THE LATEST OBS AND 06Z RA1 OPC SEA STATE
ANALYSIS. OTW...THE WV MDLS ARE IN VRY GOOD AGREEMENT OVR THE OFF
WTRS THRU WED NITE...AND ARE VRY SIMILAR TO THE 12Z GUIDANCE FROM
YESTERDAY THAT WAS USED IN THE PREV FCST. WE WILL MAKE MINOR
ADJUSTMENTS TO THE MDL GUID INITIALLY TO FIT CURRENT CONDITIONS.
OTW...WE WILL REMAIN CLOSE TO THE 00Z WNA WW3 MDL OUTPUT THRU WED
NITE.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A


.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER HOLLEY/MILLS. OCEAN PREDICTION CENTER.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.