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Atlantic Tropical Weather Discussion



000
AXNT20 KNHC 012354
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT AUG 01 2015

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...SPECIAL FEATURES...

GALE-FORCE WINDS ARE FORECAST ALONG THE COAST OF COLOMBIA 
STARTING AT 0600 UTC TONIGHT...FROM 11N TO 13N BETWEEN 74W AND 
76W. THE GALE-FORCE WINDS ARE FORECAST TO LAST FOR ABOUT 12 
HOURS. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2/ FZNT02 
KNHC...AND THE OFFSHORE FORECAST...MIAOFFNT3/FZNT23 KNHC...FOR 
MORE DETAILS. 

...TROPICAL WAVES...

AN EASTERN ATLC TROPICAL WAVE HAS AN AXIS FROM 08N27W TO 
18N26W...MOVING W AT AROUND 10 TO 15 KT OVER THE PAST 24 HOURS. 
THIS WAVE COINCIDES WITH A SHARP INVERTED 700 MB TROUGH BETWEEN 
25W AND 29W. THE LEADING EDGE OF A MODERATE POLEWARD SURGE IS 
NOTED IN SSMI TPW IMAGERY ALONG THE WAVE. CLUSTERS OF MODERATE 
CONVECTION ARE FROM 08N TO 13N BETWEEN 23W AND 31W. 

A CENTRAL ATLC TROPICAL WAVE HAS AN AXIS FROM 10N56W TO 
22N58W...MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS. THIS 
WAVE COINCIDES WITH A BROAD 700 MB INVERTED TROUGH FROM 55W TO 
63W WITH SSMI TPW IMAGERY SHOWING A POLEWARD SURGE OF MODERATE 
MOISTURE ALONG THE WAVE. ISOLATED MODERATE CONVECTION IS FROM 
19N TO 23N BETWEEN 56W AND 60W. 

A WESTERN CARIBBEAN TROPICAL WAVE HAS AN AXIS FROM 08N84W TO 
17N84W...MOVING W AT 10 TO 15 KT OVER THE PAST 24 HOURS. HIGH 
DEEP LAYER MOISTURE IS NOTED WITH THIS WAVE. WIDELY SCATTERED 
MODERATE CONVECTION IS FROM 09N TO 18N BETWEEN 80W AND 87W. 

...THE ITCZ/THE MONSOON TROUGH...                                

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF AFRICA 
NEAR 17N16W AND CONTINUES TO 12N25W...THEN RESUMES W OF A 
TROPICAL WAVE NEAR 11N28W TO A 1011 MB LOW NEAR 12N39W TO 
08N52W. OTHER THAN CONVECTION ASSOCIATED WITH THE TROPICAL 
WAVE...SCATTERED MODERATE CONVECTION IS WITHIN 200 NM OF THE 
MONSOON TROUGH AXIS BETWEEN 38W AND 52W...WITH ISOLATED MODERATE 
CONVECTION ELSEWHERE WITHIN 200 NM OF THE MONSOON TROUGH AXIS. 

...DISCUSSION...

...THE GULF OF MEXICO...                                        
A BROAD UPPER LEVEL ANTICYCLONE CENTERED OVER TX HAS AN AXIS 
THAT EXTENDS E ACROSS THE NORTHERN GULF. UPPER LEVEL DIFFLUENCE 
IS OCCURRING WITH THIS AXIS. AN UPPER TROUGH OVER THE NE US 
SUPPORTS A FRONTAL SYSTEM WITH A 1011 MB LOW CENTERED NEAR 
30N85W AND STATIONARY FRONT FROM THIS LOW ACROSS THE NORTHERN 
GULF...TO A DISSIPATING 1013 MB LOW NEAR 28N94W. A COLD FRONT 
EXTENDS FROM THE 1013 MB LOW TO NEAR THE TX/MEXICO BORDER NEAR 
26N97W. THE COMBINATION OF FORCING FROM THE EASTERNMOST LOW AND 
THE FRONT...AND UPPER LEVEL DIFFLUENCE...SUPPORTS SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION FROM 26N TO 31N BETWEEN 
THE FL W COAST AND 91W. SCATTERED SHOWERS AND THUNDERSTORMS ARE 
ELSEWHERE WITHIN 50 NM OF THE FRONTAL BOUNDARIES. E TO NE WINDS 
OF 10 TO 15 KT ARE N OF THE FRONTS. SW WINDS OF 15 TO 20 KT ARE 
WITHIN 125 NM S OF THE FRONTS. SE TO SW WINDS OF 10 TO 15 KT ARE 
S OF 24 N ACROSS THE REMAINDER OF THE GULF. THE SURFACE LOWS 
WILL DISSIPATE OVER THE NEXT 24 HOURS. THE STATIONARY FRONT WILL 
REMAIN IN TACT WITH ONGOING CONVECTION EXPECTED ACROSS THE 
NORTHERN GULF THROUGH SUNDAY. 

...THE CARIBBEAN SEA...

DIFFLUENCE BETWEEN AN UPPER LOW OVER GUATEMALA AND ANOTHER 
UPPER LOW NEAR THE BAHAMAS SUPPORTS ISOLATED MODERATE CONVECTION 
OVER THE NW CARIBBEAN MAINLY NEAR THE GREATER ANTILLES. A 
TROPICAL WAVE IS PRODUCING CONVECTION OVER THE W CARIBBEAN. 
PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. A 
TIGHT PRESSURE GRADIENT BETWEEN W ATLC HIGH PRESSURE AND LOWER 
PRESSURES OVER S AMERICA IS PRODUCING STRONG TRADE WINDS OVER 
THE S CENTRAL CARIBBEAN THIS EVENING. THESE WINDS WILL 
STRENGTHEN FURTHER TONIGHT WHICH WILL RESULT IN GALE-FORCE WINDS 
STARTING AT 0600 UTC. PLEASE REFER TO THE SPECIAL FEATURES 
SECTION FOR MORE DETAILS. MODERATE TO FRESH TRADE WINDS COVER 
THE REMAINDER OF THE CARIBBEAN BASIN. EXPECT A GENERAL DECREASE 
IN CONVECTION OVER THE CENTRAL AND WESTERN CARIBBEAN OVER THE 
NEXT 24 HOURS. SHOWERS WILL INCREASE OVER THE EASTERN CARIBBEAN 
AS A TROPICAL WAVE CROSSES THE LESSER ANTILLES LATER TONIGHT. 

...HISPANIOLA...

DEEP MOISTURE OVER THE WESTERN PORTION OF THE ISLAND SUPPORTS 
SCATTERED THUNDERSTORMS OVER HAITI THIS EVENING. THESE STORMS 
SHOULD WEAKEN LATER THIS EVENING. ADDITIONAL SHOWERS AND 
THUNDERSTORMS WILL BE POSSIBLE SUNDAY AFTERNOON AND EVENING AS A 
TROPICAL WAVE APPROACHES THE ISLAND FROM THE EAST. 


THE ATLANTIC OCEAN...      

THE EASTERN FRINGE OF AN UPPER LEVEL RIDGE AXIS EXTENDS ACROSS N 
FL AND OVER THE W ATLC TO NEAR 78W. HIGH DEEP LAYER TROPICAL 
MOISTURE IS INTERACTING WITH THE DIFFLUENCE UNDER THE RIDGE AXIS 
TO SUPPORT SCATTERED MODERATE CONVECTION FROM 26N TO 31N W OF 
78W. AN UPPER LOW IS CENTERED OVER THE CENTRAL BAHAMAS NEAR 
24N75W...SUPPORTING CLUSTERS OF MODERATE CONVECTION FROM 21N TO 
24N BETWEEN 72W AND 76W...AND SCATTERED THUNDERSTORMS FROM 24N 
TO 28N BETWEEN 71W AND 77W. FARTHER EAST...A 1023 MB HIGH 
CENTERED NEAR 30N52W DOMINATES MUCH OF THE CENTRAL AND EASTERN 
SUBTROPICAL ATLC WITH FAIR WEATHER. TWO TROPICAL WAVES ARE OVER 
THE TROPICAL ATLC. PLEASE SEE THE TROPICAL WAVES SECTION FOR 
MORE DETAILS. A 1011 MB LOW IS ALSO OVER THE TROPICAL ATLC. 
PLEASE SEE THE ITCZ/MONSOON TROUGH SECTION FOR MORE DETAILS. 
CONVECTION WILL CONTINUE W OF 72W OVER THE NEXT 24 HOURS.  

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

$$
LATTO


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Page last modified: Saturday, 01-Aug-2015 23:54:56 UTC