000
AGXX40 KNHC 181749
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
149 PM EDT THU JUL 18 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 WITH GOOD CONFIDENCE.

AN INVERTED LOW LEVEL TROUGH WILL SHIFT W ACROSS BAY OF CAMPECHE 
TONIGHT AND FRI ACCOMPANIED BY NE-E-SE 5-10 KT WIND SHIFT AND 
SEAS OF 1-3 FT. AN UPPER CYCLONE NEAR 27N87W IS SHIFTING SLOWLY 
W WITH TIME WITH AN ASSOCIATED SURFACE TROUGH EXTENDING NE-SW 
FROM THE FL BIG BEND TO THE S-CENTRAL GULF WATERS AND  
ACCOMPANIED BY A E-SE 10-15 KT WIND SHIFT. THE LOW LEVEL TROUGH 
WILL DRIFT NW TONIGHT...THEN ACCELERATE NW ON FRI DISSIPATING OVER 
THE N-CENTRAL GULF WATERS ON SAT. IN THE MEAN TIME...THE UPPER 
LOW WILL CONTINUE TO PULL TROPICAL MOISTURE N ACROSS FL AND ITS 
ADJACENT WATERS THROUGH THE WEEKEND SUPPORTING SIGNIFICANT 
CONVECTION. A NE-SW RIDGE WILL BECOME ESTABLISHED FROM N FL TO 
NE MEXICO SAT NIGHT THROUGH EARLY MON WITH E-SE WINDS AT 15-20 
KT/SEAS 3-5 FT...OVER THE WESTERN WATERS AND NE-E 20-25 KT/SEAS 
4-6 FT...OVER THE BAY OF CAMPECHE. A SURFACE HIGH WILL DEVELOP 
NEAR 27N85W ON MON WITH THE RIDGE THEN EXTENDING W TO THE TX 
COASTAL BEND WITH THE GRADIENT RELAXING OVER THE S AND W WATERS 
THEN SUPPORTING MOSTLY E-SE 10-15 KT...EXCEPT INCREASING TO 
NE-E 15-20 KT ALONG THE NW YUCATAN PENINSULA EACH EVENING. 
GUIDANCE IS IN GENERAL AGREEMENT SO CONTINUED PREVIOUS PRACTICE
OF BLENDING GFS WITH ECMWF INTO PREVIOUS OFFICIAL GRIDS.  

...CARIBBEAN SEA AND TROPICAL N ATLANTIC...                    
MODEL PREFERENCE: GFS/ECMWF BLEND WITH GOOD CONFIDENCE.

QUASI-STATIONARY ATLC HIGH PRES WILL MAINTAIN FRESH TO STRONG
TRADES ACROSS THE CENTRAL WATERS WITH PULSES TO 30 KT WITHIN
120 NM OF NW COAST OF COLOMBIA EACH EVENING INTO LATE NIGHT.
SEAS EXPECTED TO MAX AT 13 FT NEAR 13N76W. A TROPICAL WAVE ALONG 
80W HAS BEEN PROGRESSING W AT 20 KT AND WILL MOVE THROUGH THE  
GULF OF HONDURAS TONIGHT AND EARLY FRI...BUT BE ACCOMPANIED BY 
ONLY A ENE-ESE 15-20 KT WIND SHIFT WITH ENHANCED CONVECTION 
PRIMARILY TO THE S OF 12N. A SECOND TROPICAL WAVE IS MOVING W AT 
20-25 KT THROUGH THE MONA PASSAGE ATTM...AND IS ACCOMPANIED BY E-
SE 20 KT WINDS. THIS WAVE IS ACCOMPANIED BY SIGNIFICANT 
CONVECTION TO THE N OF 15N THAT WILL LIKELY INCREASE WINDS/SEAS 
LOCALLY. PRECIP GUIDANCE INDICATES POTENTIAL FOR CONTINUED 
ENHANCEMENT OF CONVECTION THROUGH FRI...THEN BACKS OFF AS THE 
UPPER LEVELS BECOME LESS FAVORABLE AS THE WAVE REACHES ALONG 78W 
ON FRI NIGHT-SAT. GUIDANCE IS IN GENERAL AGREEMENT EXCEPT GFS 
ABOUT 5 KT HIGHER ALONG COAST OF COLOMBIA...SO CONTINUED 
PREVIOUS PRACTICE OF BLENDING GFS WITH ECMWF INTO PREVIOUS 
OFFICIAL GRIDS.  

...SW N ATLANTIC W OF 55W INCLUDING THE BAHAMAS...               
MODEL PREFERENCE: GFS/ECMWF/OFFICIAL BLEND WITH GOOD CONFIDENCE.

A SURFACE TROUGH EXTENDS E ACROSS FL INTO THE W ATLC NEAR 29N78W
ACCOMPANIED BY TSTMS. THE TROUGH SHOULD MOVE W OF MARINE AREA
TONIGHT. SURFACE HIGH PRES AT 28N57W IS RIDGING WNW TO BEYOND
31N77W. AS THE TROUGH SHIFTS W OF AREA THE RIDGE WILL SHIFT S
AND EXTEND E-W ALONG 28N ON FRI...THEN MEANDER ALONG THIS POSITION
THROUGH TUE. SLY FLOW N OF THE RIDGE WILL INCREASE TO 10-15 KT
ON SAT NIGHT WITH BRIEF PERIODS OF 15-20 KT ALONG 31N DURING THE
AFTERNOONS. E WINDS AT 15-20 KT/SEAS 3-6 FT EXPECTED S OF 23N...
EXCEPT INCREASE TO E AT 20-25 KT/SEAS 4-7 FT NEAR ATLC APPROACH 
TO WINDWARD PASSAGE EACH EVENING. GUIDANCE IS IN GENERAL 
AGREEMENT EXCEPT GFS 5 KT HIGHER NEAR WINDWARD PASSAGE.    

$$

.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 NELSON. NATIONAL HURRICANE CENTER.