Marine Interpretation Message
Issued by NWS

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000
AGXX40 KNHC 310810
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
410 AM EDT THU JUL 31 2014

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

WEAK FRONTAL BOUNDARY HAS SHIFTED SLOWLY S ACROSS E PORTIONS OF
GULF PAST 6-8 HOURS...NOW EXTENDING FROM JUST N OF NAPLES...SW TO
NEAR 24.5N86W THEN NW TO UPPER TEXAS COASTAL WATERS...WITH BROAD
AND WEAK CYCLONIC FLOW ABOUT THE BOUNDARY E OF 90W...AND YIELDING
W-SW WINDS ACROSS THE W STRAITS AND INTO THE KEYS ATTM. BOUNDARY
TO DRIFT SSE TODAY ACROSS SE PORTIONS...THEN BEGIN TO DRIFT BACK
TOWARDS THE NW FRI AND SAT AND GRADUALLY DISSIPATE. NW ATLC RIDGE
TO SHIFT NW AND BUILD MODESTLY ACROSS NW PORTIONS OF SW N ATLC AND
TO E COAST OF FLORIDA THU NIGHT AND FRI...AIDING FRONTAL
MOVEMENT...WITH WEAK HIGH PREVAILING BETWEEN MOUTH OF MS AND BIG
BEND REGION...YIELDING LIGHT TO MODERATE ANTICYCLONIC FLOW ACROSS
THE BASIN. MODERATE S TO SE WINDS ACROSS UPPER MEXICAN AND TEXAS
COASTAL WATERS LIKELY TO BECOME ENHANCED BY DIURNAL HEATING EACH
AFTERNOON AND REACH 15-20 KT FOR A FEW HOURS...INCREASING SEAS
LOCALLY TO 4 FT...AND VERY ISOLATED SPOTS TO 5 FT. LIKEWISE...
LATE AFTERNOON/EVENING THERMAL TROUGH ALSO EXPECTED TO YIELD NEAR
20 KT WINDS OFF NW AND W COASTS OF YUCATAN EACH DAY...YIELDING
SEAS PEAKING BRIEFLY AT 3-5 FT EACH DAY. OTHERWISE...TRANQUIL
CONDITIONS EXPECTED THROUGH THE WEEKEND.

...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 64W...

MODEL PREFERENCE: GFS-ECMWF CONSENSUS

GFS AND ECMWF HAVE COME IN VERY GOOD AGREEMENT IN ASSOCIATION
WITH TROPICAL LOW NEAR 50W ATTM...AND ASSOCIATED CONDITIONS AS THE
LOW MOVES ACROSS THE LEEWARDS...THE VIRGIN ISLANDS...AND PORTIONS
OF PUERTO RICO 36-72 HRS. FRESH TRADE PRESENTLY PREVAIL IN NORMAL
POSITION OF CARIB JET...OFF COAST OF COLOMBIA...AND EXPECTED TO
PEAK AROUND 25 KT THIS MORNING...WITH SEAS 8-10 FT.
OTHERWISE...BROAD AND WEAKLY CYCLONIC TURNING OCCURRING IN WIND
FIELD ACROSS THE BASIN ATTM...WITH MODERATE TO FRESH TRADES AND
SEAS LESS THAN 8 FT...EXCEPT OFFSHORE WATERS N OF PANAMA. NO
SIGNIFICANT CHANGES EXPECTED WITH THESE CONDITIONS THROUGH FRI...
EVEN AS TROPICAL LOW APPROACHES LEEWARDS AND MOVES ACROSS PORTIONS
OF NE CARIB FRI NIGHT THROUGH SAT NIGHT. RIDGING BEHIND EXITING
LOW TO THE NW LATE SAT AND SUN WILL EXPAND FRESH TRADES
SIGNIFICANTLY ACROSS THE BASIN E OF 80W...IN ASSOCIATION WITH NEXT
TROPICAL WAVE APPROACHING LESSER ANTILLES SUN NIGHT.

TROPICAL LOW ALONG 50W THIS MORNING STILL STRUGGLING AGAINST DRY
AIR INTRUSION ACROSS MOST OF N SEMICIRCLE...WHICH IS FINALLY MORE
OBVIOUS BASED ON GOES-R PROVING GROUND IMAGERY AND CIMSS SAL
PRODUCTS. GLOBAL MODELS SUGGEST THERE IS AN OPPORTUNITY FOR
BEST MOISTURE CURRENTLY ACROSS SE SEMICIRCLE OF SYSTEM TO WRAP UP
AROUND LOW FRI AND FRI NIGHT AS LOW APPROACHES AND THEN REACHES
LEEWARDS...AND THIS MAY BE THE WINDOW OF OPPORTUNITY FOR TROPICAL
CYCLONE FORMATION. MODELS ALSO SUGGEST CONVECTIVE PATTERN TO SHIFT
FROM ACROSS E AND NE PORTIONS AS SYSTEM MOVES ACROSS
LEEWARDS...VIRGIN ISLANDS...AND PUERTO RICO FRI NIGHT THROUGH SUN
AND COULD REDUCE RAINFALL POTENTIAL FOR VIRGIN ISLANDS AND P.R.
WHERE RAIN IS NEEDED. GFS AND ECMWF CURRENTLY IN EXCELLENT
AGREEMENT THROUGH 72 HOURS AND CONFIDENCE IN FORECAST HAS
INCREASED SIGNIFICANTLY. GALE WARNING MAY BE NEEDED ACROSS NE
SEMICIRCLE 36-72 HRS IF CONVECTION DOES NOT INCREASE ABOUT
SYSTEM...WITH ASSOCIATED SEAS OF 12-15 FT MOVING THROUGH NEAR AND
OFFSHORE COASTAL WATERS OF LEEWARDS AND NE CARIB ISLANDS DURING
THIS TIME FRAME. NEW 06Z RUN OF NWPS SHOULD REFLECT THESE VALUES.

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

MODEL PREFERENCE: ECMWF-GFS CONSENSUS

WEAK FRONTAL BOUNDARY ACROSS FAR NW PORTIONS HAS ALREADY STALLED
AND WILL DRIFT BACK TOWARD THE NW LATER TODAY AND TONIGHT AND
INLAND ACROSS SE U.S. AND FLORIDA BY 36 HOURS. RIDGING CONTINUES
FROM NW ATLC...SW TO CENTRAL BAHAMAS AND STRAITS OF FL ALONG
80W...AND WILL SHIFT SLIGHTLY NW NEXT FEW DAYS AS DEEP LAYERED LOW
ACROSS CENTRAL ATLC DIGS SW AND FORCES WEAK RIDGE SLIGHTLY NW
ACROSS THE W AND SW N ATLC. MODERATE SE TRADES CURRENTLY FROM SE
WATERS INTO TURKS AND CAICOS WILL SPREAD SLIGHTLY NW THROUGH FRI
AND INTO CENTRAL BAHAMAS AND ATLC WATERS TO THE E...INCREASING
SEAS TO 4-5 FT. TROPICAL LOW... EXPECTED TO EXIT ATLC COASTAL
WATERS OF PUERTO RICO SAT EVENING-SAT NIGHT AND CONTINUE ALONG A
NW COARSE THROUGH SE WATERS. WHILE GLOBAL MODELS SUGGEST SLOW
WEAKENING SUN THROUGH MON...DYNAMIC FETCH OF NE SEMICIRCLE OF LOW
WILL MAINTAIN SEAS 10-12 FT LIKELY THROUGH MON AFTERNOON IN THIS
SEMICIRCLE BEFORE GRADUALLY DIMINISHING INTO TUE. RIDGING BEHIND
THE LOW WILL COMBINE WITH NEXT TROPICAL WAVE TO REACH THE LESSER
ANTILLES MON-TUE FOR FRESH TO STRONG TRADES ACROSS SE WATERS AND
SPREADING NW IN WAKE OF TROPICAL LOW PASSING JUST E OF CENTRAL AND NW
BAHAMAS. AGAIN...CONFIDENCE IN FORECAST HAS INCREASED WITH GLOBAL
MODELS IN GOOD AGREEMENT THROUGH DAY 5...AND CONTINUE TO FORECAST
RECURVATURE TOWARD THE NNW DAY 4 AND 5.

$$

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

.GULF OF MEXICO...
     NONE.

.CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 64W...
     NONE.

.SW N ATLANTIC INCLUDING THE BAHAMAS...
     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.HURRICANE WARNINGS.GOV/MARINE

$$

.FORECASTER STRIPLING. NATIONAL HURRICANE CENTER.



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