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Atlantic Tropical Weather Discussion



000
AXNT20 KNHC 201215 CCA
TWDAT 

TROPICAL WEATHER DISCUSSION...
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED AUG 20 2014

CORRECTION TO THE SPECIAL FEATURES SECTION
INCLUDING A MEDIUM CHANCE FOR DEVELOPMENT

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 
1015 UTC.

...SPECIAL FEATURES...                                          
A 1009 MB LOW IS CENTERED NEAR 10N53W AND REMAINS EMBEDDED 
WITHIN LOW-LEVEL CYCLONIC MONSOONAL FLOW ACROSS THE TROPICAL 
ATLC. A TROPICAL WAVE TO THE EAST-NORTHEAST OF THE LOW IS 
EXPECTED TO INJECT ENERGY INTO THE LOW DURING THE NEXT 24 TO 48 
HOURS WITH MOST GLOBAL MODELS SUGGESTING DEVELOPMENT OF THE 
SURFACE LOW THAT TRACKS W-NW TOWARD THE LEEWARD ISLANDS AND NE 
CARIBBEAN BY FRIDAY. WIDELY SCATTERED MODERATE CONVECTION IS 
FROM 06N-12N BETWEEN 51W-57W. THE CHANCE OF THIS SYSTEM 
DEVELOPING INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS IS 
MEDIUM.

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS FROM 16N19W TO 24N19W MOVING W AT 10-15 
KT. THE WAVE HAS EMERGED OFF THE WEST AFRICAN COAST DURING THE 
PAST 12 HOURS AND COINCIDES WITH AN AMPLIFIED 700 MB TROUGH 
BETWEEN 16W-24W AND 850 MB RELATIVE VORTICITY FOCUSED IN THE 
VICINITY OF 14N21W WITHIN THE MONSOON TROUGH AXIS AND IN 
VICINITY OF A 1013 MB LOW ALONG THE WAVE AXIS NEAR 21N. NO 
SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 13N45W TO 23N51W MOVING W AT 20 KT. 
THE WAVE COINCIDES WITH 700 MB TROUGHING ALOFT AND A MAXIMUM IN 
850 MB RELATIVE VORTICITY NOTED ALONG THE MONSOON TROUGH AXIS 
BETWEEN 40W AND 50W. NO SIGNIFICANT CONVECTION IS OCCURRING WITH 
THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N59W TO 21N61W MOVING W AT 20 KT. 
700 MB TROUGHING ASSOCIATED WITH THE WAVE HAS LIKELY MERGED WITH 
MID-LATITUDE 700 MB TROUGHING OVER THE CENTRAL ATLC...HOWEVER 
RESIDUAL ENERGY CONTINUES TO MOVE WEST OF THE 1009 MB SPECIAL 
FEATURES LOW EMBEDDED WITHIN THE MONSOON TROUGH NEAR 10N53W. NO 
SIGNIFICANT CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 08N93W TO 19N95W MOVING W AT 20 KT. 
MOST OF THE ENERGY ASSOCIATED WITH THIS WAVE LIES IN THE EAST 
PACIFIC REGION...HOWEVER 850 MB RELATIVE VORTICITY FIELDS REMAIN 
MAXIMIZED ACROSS PORTIONS OF SOUTHERN MEXICO AND GUATEMALA THAT 
CONTINUE TO SUPPORT ISOLATED MODERATE TO STRONG CONVECTION FROM 
14N-19N BETWEEN 93W-98W.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N16W TO 
13N26W TO 15N39W TO A 1009 MB LOW PRES NEAR 10N53W TO 08N59W. 
ISOLATED MODERATE CONVECTION IS FROM 12N-15N BETWEEN 25W-28W... 
AND FROM 08N-13N BETWEEN 43W-51W.

...DISCUSSION... 

GULF OF MEXICO...                                               
AN UPPER LEVEL LOW IS CENTERED NEAR 23N97W THAT INFLUENCES MUCH 
OF THE WESTERN GULF W OF 90W WITH MOIST SOUTH-SOUTHWESTERLY FLOW 
ALOFT. WHILE SURFACE RIDGING EXTENDS ALONG 28N ACROSS THE 
BASIN...DYNAMICS ASSOCIATED WITH THE UPPER LEVEL LOW IS 
ADVECTING MOISTURE NORTHWARD AND GENERATING WIDELY SCATTERED 
SHOWERS AND ISOLATED TSTMS ACROSS THE NW GULF WATERS FROM 24N-
28N BETWEEN 91W-96W. ELSEWHERE...THE SURFACE RIDGE EXTENDING 
FROM THE SW NORTH ATLC IS PROVIDING FOR OVERALL FAIR CONDITIONS 
AND MOSTLY CLEAR SKIES ACROSS THE EASTERN GULF THIS MORNING. A 
FEW ISOLATED SHOWERS AND TSTMS ARE NOTED FROM 24N-26N BETWEEN 
82W-96W DUE TO WEAK LOW-LEVEL MOISTURE CONVERGENCE AND WEAK 
MIDDLE TO UPPER LEVEL SOUTHWESTERLY FLOW ALOFT ON THE WESTERN 
PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED OVER THE 
SOUTHERN FLORIDA PENINSULA NEAR 26N81W. THE SURFACE RIDGE IS 
EXPECTED TO REMAIN ANCHORED ALONG 28N/29N THROUGH SUNDAY WITH 
GENTLE TO MODERATE EAST WINDS.

CARIBBEAN SEA...                                                
A MAJORITY OF THE CARIBBEAN IS UNDER THE INFLUENCE OF DRY UPPER 
LEVEL CYCLONIC CIRCULATIONS ALOFT...ONE CENTERED OVER THE NW 
CARIBBEAN NEAR 19N82W AND THE OTHER CENTERED NEAR 22N64W THAT 
EXTENDS UPPER LEVEL TROUGHING OVER MUCH OF THE EASTERN CARIBBEAN 
E OF 72W. WATER VAPOR IMAGERY CONFIRMS THE DRY AIR ALOFT AND 
THIS IS PROVIDING FOR OVERALL STABLE CONDITIONS THIS MORNING... 
HOWEVER ISOLATED SHOWERS ARE OCCURRING ACROSS THE NE CARIBBEAN N 
OF 16N BETWEEN 63W-71W. THE AREA OF LOW-LEVEL MOISTURE ACROSS 
THE NE CARIBBEAN HAS CONTINUED TO MOVE WEST-SOUTHWESTWARD DURING 
THE PAST 24 HOURS AS A TROPICAL WAVE APPROACHES FROM THE EAST. 
OTHERWISE...SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE 
SW CARIBBEAN IN AN AREA OF MAXIMUM LOW-LEVEL MOISTURE 
CONVERGENCE AND WITHIN CLOSE PROXIMITY TO THE MONSOON TROUGH 
AXIS ALONG 09N/10N. MODERATE TO FRESH TRADES ARE EXPECTED TO 
PERSIST GENERALLY S OF 17N BETWEEN 68W-80W.

...HISPANIOLA...                                         
CURRENTLY...ISOLATED SHOWER ACTIVITY CONTINUES ACROSS FAR 
EASTERN PORTIONS OF THE ISLAND AND ADJACENT COASTAL WATERS IN 
THE MONA PASSAGE WITH LOW-LEVEL MOISTURE COVERING A LARGE AREA 
TO THE EAST ACROSS THE NE CARIBBEAN SEA FROM 16N-21N BETWEEN 63W-
71W. THE APPROACH OF A WEAK TROPICAL WAVE WILL ALSO IMPACT THE 
ISLAND DURING THE NEXT 24 TO 48 HOURS WITH THE USUAL POSSIBILITY 
OF AFTERNOON AND EVENING CONVECTION DUE TO PEAK DAYTIME HEATING 
AND INSTABILITY.

ATLANTIC OCEAN...                                               
A MIDDLE TO UPPER LEVEL RIDGE IS ANCHORED OVER THE SW NORTH ATLC 
NEAR 26N81W THAT EXTENDS AN AXIS NE TO 32N70W SUPPORTING SURFACE 
RIDGING ACROSS MUCH OF THE SW NORTH ATLC W OF 60W. TO THE NORTH 
OF THE SURFACE RIDGE AXIS ALONG 27N/28N...LOWER PRESSURE OFF THE 
COAST OF THE DELMARVA EXTENDS WEAK SURFACE TROUGHING ALONG THE 
EASTERN SEABOARD AS A SURFACE TROUGH ANALYZED FROM 27N81W TO 
BEYOND 32N78W WITH ISOLATED SHOWERS AND TSTMS OCCURRING WITHIN 
90 NM EITHER SIDE OF THE BOUNDARY N OF 28N. OTHERWISE...THE 
REMAINDER OF THE SW NORTH ATLC REMAINS UNDER MOSTLY FAIR SKIES 
AND CONDITIONS THIS MORNING. FARTHER EAST...THE REMAINDER OF THE 
CENTRAL AND EASTERN ATLC ARE ALSO UNDER THE INFLUENCE OF A 
SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED SW OF THE 
AZORES NEAR 34N35W.

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

$$
HUFFMAN



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Page last modified: Wednesday, 20-Aug-2014 12:15:45 UTC