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Atlantic Tropical Discussion

Active Tropical Systems Basin Outlooks Satellite
Atlantic Basin Tropical Discussion
 
300 
AXNT20 KNHC 121035
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUL 12 2014

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL  
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF 
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE 
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE 
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL 
ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...                                            
TROPICAL WAVE CAME OFF THE WEST AFRICAN COAST ENGULFED BY THE 
SAHARAN AIR LAYER EARLIER THIS MORNING. THE SOUTHERN PORTION OF 
THE WAVE IS EMBEDDED IN THE MONSOON TROUGH WHICH IS SUPPORTING A 
CLUSTER OF MODERATE/STRONG CONVECTION AND TSTMS SE OF THE AXIS 
FROM 8N-12N E OF 19W.

TROPICAL WAVE IS OVER THE CENTRAL ATLC JUST N OF THE ITCZ WITH 
AXIS EXTENDING FROM 19N43W TO 9N44W MOVING W AT 20-25 KT. THE 
WAVE IS COMPLETELY EMBEDDED IN THE DRY SAHARAN AIR LAYER WHICH 
IS HINDERING DEVELOPMENT OF DEEP CONVECTION AT THE TIME. 

TROPICAL WAVE IS LOCATED OVER THE CENTRAL CARIBBEAN WITH AXIS 
EXTENDING FROM 20N74W TO 10N76W MOVING W AT 20 KT. DEEP LAYER 
MOISTURE IS ASSOCIATED WITH THE WAVE. HOWEVER...STRONG DEEP 
LAYER ENVIRONMENTAL SHEAR IS INHIBITING THE DEVELOPMENT OF 
CONVECTION OVER CARIBBEAN WATERS. SCATTERED MODERATE CONVECTION 
AND TSTMS ARE OVER THE WINDWARD PASSAGE COINCIDING WITH AN AREA 
OF UPPER-LEVEL DIFFLUENCE.

TROPICAL WAVE HAS MOVED ACROSS THE YUCATAN PENINSULA...NORTHERN 
CENTRAL AMERICA AND THE E PAC WATERS. ITS AXIS EXTENDS FROM 
20N87W TO 9N90W MOVING W AT 20-25 KT. TOTAL PRECIPITABLE WATER 
IMAGERY SHOWS LIMITED MOISTURE ACROSS THIS REGION...THUS 
RESULTING IN A LACK OF ANY SIGNIFICANT DEEP CONVECTION OVER 
WATER AT THIS TIME.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 9N13W TO 
7N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 
7N18W TO 8N38W TO 6N57W. BESIDES THE CONVECTION ASSOCIATED WITH 
THE WAVES...SCATTERED MODERATE CONVECTION IS FROM 4N-10N BETWEEN 
19W-32W.

...DISCUSSION...

GULF OF MEXICO...                                               
SURFACE HIGH PRESSURE AND RIDGING CONTINUE TO DOMINATE THE GULF 
WATERS. IN THE MID-UPPER LEVELS...AN ANTICYCLONIC CIRCULATION 
CENTERED OVER MISSOURI EXTENDS A RIDGE AXIS TO THE NORTHERN AND 
WESTERN GULF TO SUPPORT A PAIR OF HIGHS...A 1020 MB HIGH NEAR 
29N93W AND A 1019 MB HIGH NEAR 28N87W. A MODERATE MOIST AIRMASS 
HAS BEEN MOVING ACROSS THE GULF FROM THE SW N ATLC AND THE NW 
CARIBBEAN. A MID-LEVEL INVERTED TROUGH IS OVER THE EASTERN GULF 
AND SUPPORTS A SURFACE TROUGH ALONG WESTERN FLORIDA COASTAL 
WATERS FROM 30N84W TO 24N83W. MOISTURE AT THE LOW-MID LEVELS 
ALONG WITH TROUGHINESS ALOFT SUPPORT SCATTERED HEAVY SHOWERS AND 
TSTMS E OF 86W. SCATTERED SHOWERS EXTENDS INTO THE STRAITS OF 
FLORIDA. ISOLATED SHOWERS/TSTMS ARE WITHIN 90 NM OFF THE 
NORTHERN GULF COAST E OF 91W. OTHERWISE...THE SURFACE RIDGE IS 
FORECAST TO REMAIN ANCHORED ACROSS THE NORTHERN GULF WATERS 
THROUGH SATURDAY WITH LIGHT WINDS EXPECTED DURING THE WEEKEND. 
TWO TROPICAL WAVES WILL MOVE INTO THE BAY OF CAMPECHE IN THE 
NEXT TWO DAYS ENHANCING SHOWERS IN THE REGION.

CARIBBEAN SEA...                                               
AN UPPER LEVEL LOW IS CENTERED OVER CENTRAL CUBA WHERE ALONG 
WITH DEEP LAYER MODERATE MOIST AIR ACROSS PORTIONS OF THE NW 
CARIBBEAN SUPPORT ISOLATED HEAVY SHOWERS AND TSTMS N OF 18N 
BETWEEN 78W-85W. TWO TROPICAL WAVES ARE MOVING ACROSS THE BASIN. 
REFER TO THE TROPICAL WAVES SECTION FOR DETAILS. DIFFLUENT FLOW 
ALOFT AND A TROPICAL WAVE STARTING TO MOVE ACROSS EASTERN CUBA 
SUPPORT SCATTERED SHOWERS AND TSTMS OVER THE WINDWARD PASSAGE 
AND ISOLATED SHOWERS ACROSS HISPANIOLA. IN THE SW 
CARIBBEAN...THIS SHOWER ACTIVITY IS BEING ENHANCED IN PART BY 
THE MONSOON TROUGH AXIS MOVING ACROSS COSTA RICA AND PANAMA. 
FRESH TO STRONG TRADES ARE FORECAST TO PERSIST THROUGH THE 
WEEKEND INTO EARLY NEXT WEEK.

...HISPANIOLA...                                        
CURRENTLY SCATTERED/ISOLATED SHOWERS ARE OCCURRING ACROSS THE 
ISLAND AS A TROPICAL WAVE MOVED ACROSS THE CENTRAL CARIBBEAN 
SEA. AN UPPER LEVEL LOW IS ALSO CENTERED TO THE W-NW OF THE 
ISLAND OVER CENTRAL CUBA AND IS PLACING HISPANIOLA WITHIN AN 
AREA OF UPPER LEVEL DIFFLUENCE THAT SUPPORTS THIS CONVECTION. AS 
THE WAVE PASSES TO THE WEST DURING THE NEXT 24 HOURS...THE UPPER 
LEVEL LOW IS ALSO EXPECTED TO DRIFT WESTWARD AND GRADUALLY 
WEAKEN IMPROVING CONDITIONS SLOWLY BY MONDAY.

ATLANTIC OCEAN...                                               
A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY 
ALONG THE EASTERN U.S. SEABOARD THAT SUPPORTS A FRONTAL BOUNDARY 
N OF THE AREA OF DISCUSSION. AN ANTICYCLONIC CIRCULATION 
CENTERED OVER MISSOURI EXTENDS A RIDGE AXIS ACROSS FLORIDA AND 
PORTIONS OF THE SW N ATLC. THIS ENVIRONMENTAL PATTERN ALOFT IS 
FAVORING UPPER LEVEL DIFFLUENCE WHICH ALONG MOIST AIR ON THE 
REGION SUPPORT SCATTERED SHOWERS AND TSTMS N OF 22N W OF 77W AS 
WELL AS FROM 19N-23N BETWEEN 70W-75W. FARTHER EAST...A MID-UPPER 
LOW SUPPORT HEAVY SHOWERS AND TSTMS FROM 23N-31N BETWEEN 55W-
62W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE 
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1030 MB HIGH CENTERED 
NEAR 38N47W.

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

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NR