000
AGXX40 KNHC 270751
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
351 AM EDT FRI SEP 27 2013

MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN
SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND
64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS.

...GULF OF MEXICO...

MODEL PREFERENCE: GFS/ECMWF BLEND

E COAST MID-UPPER TROUGH SHIFTING SLOWLY ESE ATTM AND FORCING WEAK
FRONTAL TROUGH ASSOCIATED WITH SECONDARY SFC LOW OFF OF FL COAST
SOUTHWARD THROUGH S FL EXTENDING WWD ALONG ABOUT 25N. NELY FLOW
BEGINNING TO SPILL INTO NE GULF WITH BUOY OBS GENERALLY 3 FT.
ANTICYCLONIC FLOW N OF WEAK BOUNDARY PRODUCING SE WINDS 15 KT
ALONG TEXAS COASTAL WATERS ATTM WITH SEAS THERE ALSO 3 FT. FRONTAL
TROUGH WILL SINK SWD INTO STRAITS OF FL BY AFTERNOON WITH NELY
FLOW AROUND 15 KT PREVAILING ACROSS BIG BEND REGION AND NE
PORTIONS THROUGH SUN AFTERNOON BEFORE DIMINISHING SLIGHTLY.
CURRENT PATTERN TO PREVAIL THROUGH MON WITH SLIGHTLY COOLER DRY
AIR TO SPREAD SW ACROSS THE NE HALF OF THE GULF BY SAT NIGHT.

...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 65W...

MODEL PREFERENCE: GFS/ECMWF BLEND

LIGHT TO MODERATE WINDS PREVAIL ACROSS ENTIRE BASIN THIS MORNING
WITH RECENT SCAT PASSES INDICATING MAX WINDS 15-20 KT 68-70W S OF
14N WHERE SEAS LIKELY 6-7 FT. STRONG OF LOWS MOVING ACROSS SW N
ATLC AND SUPPORTING UPPER TROUGH HAS DISPLACED ATLC RIDGE TO THE
E ANCHORED ON A 1019 MB HIGH. VERY WEAK GRADIENT THUS PREVAILS
ACROSS BASIN ATTM...WITH WEAK TROPICAL WAVE ACROSS TROPICAL N ATLC
WATERS APPROACHING 60W ATTM AND SIGNIFICANT WAVE NEAR 50W
INTERACTING WITH CUT OFF UPPER LOW AT 21N53W. GLOBAL MODELS
SUGGEST OCT MONSOONAL LOW TO BEGIN TO EMERGE ACROSS SW CARIB NEXT
FEW DAYS AND WILL BACK MILD FLOW ACROSS NW PORTIONS TO NE. ATLC
RIDGE WILL ALSO ATTEMPT TO BUILD WEAKLY WWD TO AROUND 60W AND
INDUCE SUFFICIENT GRADIENT TO THE E OF CARIB LOW FOR PERSISTENT
15-20 TRADES ACROSS CENTRAL CARIB THROUGH SAT NIGHT BEFORE RIDGE
BUILDS A LITTLE FURTHER W AND THIS AREA OF TRADES SHIFTS WNW
TOWARDS JAMAICA...WITH MAX SEAS 6-7 FT SHIFTING WNW IN TANDEM.
TROPICAL WAVE TO WEAKEN CONSIDERABLY NEXT 48 HOURS AS THEY
ENCOUNTER WEAK STEERING FLOW AND BEGIN TO ROUND WRN PERIPHERY OF
ATLC RIDGE AND MOVE MORE NW ACROSS NE CARIB...STRETCHING AND
SHEARING MOISTURE TO THE NE. DEEP LAYERED TROUGHING ACROSS W ATLC
WILL COME SOMEWHAT INTO PHASE WITH MONSOONAL LOW IN SW CARIB SUN
THROUGH MON TO BEGIN TO PRODUCE MOISTURE CONVERGENCE ACROSS
LIFTING NW OUT OF S CENTRAL CARIB AND ACROSS JAMAICA...HAITI AND
WINDWARD PASSAGE...TO YIELD ACTIVE WEATHER.


...SW N ATLANTIC INCLUDING THE BAHAMAS...

MODEL PREFERENCE: GEFS/ECMWF BLEND 

MODELS STILL NOT IN GREAT AGREEMENT WITH EVOLUTION OF LOWS
SWEEPING ACROSS N PORTIONS OF AREA...WITH FIRST LOW LIFTING OUT TO
THE TONIGHT...AND MINIMAL GALES INDICATED BY SCAT PASSES THIS
AFTERNOON IN SE SEMICIRCLE...WITH SECONDARY LOW NOW NEAR 29N75.5W
AND MOVING E-SE. THIS PUSHING FRONTAL TROUGH MENTIONED ABOVE SWD
THROUGH NW BAHAMAS AND INTO S FL...AND EXPECTED TO SINK INTO
STRAITS BY AFTERNOON THEN INTO NW CUBA BY 24 HOURS THEN MEANDER
NEXT FEW DAYS. GLOBAL MODELS SHOW VARIOUS VERSIONS OF ELONGATE
LLVL VORTICITY WITH THIS FEATURE...WITH GFS LIFTING OUT MORE
QUICKLY THAN OTHER MODELS...AND HAVE USED A CONSENSUS OF GEFS MEAN
AND ECMWF...WHICH WAS NOT TOO DISSIMILAR TO UKMET. MODELS SUGGEST
AN OCCLUDED LOW WITH NE WINDS 20-25 KT ACROSS NW QUAD AND REMOVED
FROM CENTRAL CIRCULATION OF LOW AS IT SHIFT E NEXT 24 HOURS THEN
LIFTS OUT NE QUICKLY AFTER 48 HOURS. NELY FLOW ACROSS ATLC TO NW
OF OCCLUSION TO SPREAD ACROSS FL WATERS THROUGH EARLY SUN AND WILL
BUILD SEAS 6-9 FT...WITH ENOUGH NLY COMPONENT TO ALLOW SOME WAVE
ENERGY TO GET IN BEHIND BAHAMAS AND INTO SE FL COASTAL WATERS
TONIGHT THROUGH SUN. OTHERWISE...SWLY FLOW 20-30 KT OCCURRING TO
SE OF FIRST LOW LIFTING OUT CURRENTLY TO PREVAIL ACROSS NE
PORTIONS THROUGH THIS MORNING BEFORE EXITING AREA...WITH FRONT
CONNECTING THE TWO LOWS MEANDERING ACROSS NE PORTIONS THROUGH 48
HOURS. 

$$

.WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE
COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE:

.GULF OF MEXICO...
GMZ011...NONE.
GMZ013...NONE.
GMZ015...NONE.
GMZ017...NONE.
GMZ019...NONE.
GMZ021...NONE.
GMZ023...NONE.
GMZ025...NONE.

.CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 64W...
AMZ011...NONE.
AMZ013...NONE.
AMZ015...NONE.
AMZ017...NONE.
AMZ019...NONE.
AMZ021...NONE.
AMZ023...NONE.
AMZ025...NONE.
AMZ027...NONE.
AMZ029...NONE.
AMZ031...NONE.
AMZ033...NONE.
AMZ035...NONE.
AMZ037...NONE.
AMZ039...NONE.

.SW N ATLANTIC INCLUDING THE BAHAMAS...
AMZ111...NONE.
AMZ113...NONE.
AMZ115...NONE.
AMZ117...NONE.
AMZ119...NONE.
AMZ121...NONE.
AMZ123...NONE.
AMZ125...NONE.
AMZ127...NONE.

*FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT:
HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF

NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE
NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT:
HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP

FOR ADDITIONAL INFORMATION PLEASE VISIT:
HTTP://WWW.HURRICANES.GOV/MARINE

$$
.FORECASTER STRIPLING. NATIONAL HURRICANE CENTER.