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Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 311043
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 31 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 
1015 UTC.

...SPECIAL FEATURES...                                          
A 1010 MB LOW IS CENTERED NEAR 11N49W MOVING W-NW AT 15 KT. THE 
LOW CONTINUES TO SHOW A MARGINALLY IMPRESSIVE SATELLITE 
PRESENTATION. DURING THE PAST FEW HOURS HOWEVER...THE LOW-LEVEL 
CIRCULATION CENTER HAS BECOME PARTIALLY EXPOSED TO THE WEST OF 
THE STRONGEST CONVECTION. SCATTERED MODERATE CONVECTION IS 
OCCURRING WITHIN 120 NM OF THE CENTER IN THE SE SEMICIRCLE. IN 
ADDITION...EARLIER EVENING ASCAT PASSES AROUND 31/0022 UTC AND 
31/0110 UTC INDICATED A 20 TO 30 KT WIND FIELD SURROUNDING THE 
LOW WITHIN 90 NM OF CENTER. PLEASE SEE THE LATEST NHC TROPICAL 
WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20 KNHC FOR 
MORE DETAILS.

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS FROM 09N30W TO 16N31W MOVING W AT 5-10 KT. 
A BROAD LOW-LEVEL...850 MB-700 MB...CYCLONIC CIRCULATION IS 
NOTED IN THE VICINITY OF THE WAVE AND ACROSS AN AREA FOCUSED 
NEAR A 1012 MB SURFACE LOW CENTERED AT THE SOUTHERN EXTENT OF 
THE WAVE AXIS NEAR 09N30N. THE BROAD AREA OF 850 MB RELATIVE 
VORTICITY IS NOTED FROM 08N-11N BETWEEN 28W-33W. CONVECTION 
REMAINS LIMITED DUE TO THE SAHARAN AIR LAYER COVERING MUCH OF 
THE TROPICAL ATLC...HOWEVER WIDELY SCATTERED MODERATE CONVECTION 
IS FROM 08N-13N BETWEEN 30W-34W.

TROPICAL WAVE EXTENDS FROM 10N56W TO 20N58W MOVING W AT 15-20 
KT. THE WAVE REMAINS TO THE W-NW OF THE SPECIAL FEATURES 1010 MB 
SURFACE LOW CENTERED NEAR 11N49W. A PORTION OF ENERGY ASSOCIATED 
WITH THE WAVE HAS FRACTURED TO THE NORTH...LARGELY STRETCHING OF 
THE 700 MB TROUGHING...AND IS ANALYZED AS A SURFACE TROUGH FROM 
21N58W TO 25N56W. SATELLITE IMAGERY AND GLOBAL MODEL DATA 
INDICATE THE REMAINDER OF THE WAVE ENERGY IS EMBEDDED WITHIN A 
700 MB TROUGH THAT COINCIDES WITH THE WAVE AXIS. NO SIGNIFICANT 
DEEP CONVECTION IS NOTED WITH THE WAVE AT THIS TIME.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 19N17W TO 
13N20W TO A 1012 MB LOW PRES NEAR 09N31W TO 05N40W. WIDELY 
SCATTERED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 12W-
20W...AND FROM 04N-08N BETWEEN 31W-40W.

...DISCUSSION...

GULF OF MEXICO...                                              
BROAD LONGWAVE UPPER LEVEL TROUGHING IS OVER THE EASTERN CONUS 
THAT SUPPORTS A 1014 MB LOW CENTERED NEAR JACKSONVILLE FLORIDA 
WITH A STATIONARY FRONT ANALYZED SOUTHWARD ACROSS THE SPINE OF 
THE FLORIDA PENINSULA AND INTO THE GULF WATERS NEAR FORT MYERS. 
THE FRONT CONTINUES SW TO 24N86W THEN NW TO 25N90W WHERE IT 
BEGINS DISSIPATING TO THE TEXAS COAST NEAR 29N95W. ISOLATED 
SHOWERS AND TSTMS ARE OCCURRING WITHIN 45 NM EITHER SIDE OF THE 
FRONT AND N OF 24N BETWEEN 81W-83W. OTHERWISE...A SURFACE RIDGE 
IS ANCHORED ON EITHER SIDE OF THE FRONTAL BOUNDARY WITH A RIDGE 
AXIS EXTENDING ALONG 22N ACROSS CUBA TO THE EAST MEXICO COAST. 
TO THE NORTH OF THE FRONT...THE OTHER SURFACE RIDGE IS ANCHORED 
BY A 1017 MB HIGH CENTERED OVER SOUTHERN MISSISSIPPI NEAR 
31N90W. LOOKING AHEAD...THE FRONTAL BOUNDARY IS FORECAST TO 
BECOME DIFFUSE THROUGH FRIDAY. MEANWHILE...WEAK RIDGING IS 
EXPECTED TO REMAIN ACROSS THE WESTERN AND CENTRAL GULF THROUGH 
FRIDAY.

CARIBBEAN SEA...                                       
RELATIVELY DRY AND STABLE CONDITIONS ALOFT ARE NOTED OVER MUCH 
OF THE CARIBBEAN THIS MORNING FOCUSED ON AN ELONGATED UPPER 
LEVEL LOW CENTERED NEAR 17N81W AND AN UPPER LEVEL ANTICYCLONIC 
CIRCULATION CENTERED NEAR 11N66W. GIVEN MARGINAL LIFTING 
DYNAMICS IN ASSOCIATION WITH THE UPPER LEVEL LOW...ISOLATED 
SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM OF THE SOUTHERN 
COAST OF CUBA. OTHERWISE...CONDITIONS ACROSS THE NW CARIBBEAN 
REMAIN FAIR WITH MOSTLY CLEAR SKIES THIS MORNING. FARTHER 
EAST...MOSTLY CLEAR SKIES PREVAIL WITH THE UPPER LEVEL RIDGING 
PROVIDING AN OVERALL SUBSIDENT ENVIRONMENT...HOWEVER LOW-LEVEL 
MOISTURE INCREASES E OF 66W WITH THE APPROACH OF A TROPICAL WAVE 
CURRENTLY ALONG 58W. OTHERWISE...THE ONLY OTHER CONVECTION 
OCCURRING IS SCATTERED SHOWERS AND TSTMS ALONG THE COASTS OF 
PANAMA AND COSTA RICA S OF 11N BETWEEN 77W-83W DUE TO THE CLOSE 
PROXIMITY OF THE MONSOON TROUGH ALONG 08N/09N. FINALLY... 
MODERATE TO FRESH TRADES PERSIST WITH THE STRONGEST AREA OF 
WINDS EXPECTED S OF 14N BETWEEN 68W-77W.

...HISPANIOLA...                                        
CURRENTLY...THE ISLAND REMAINS NEAR THE BASE OF AN UPPER LEVEL 
LOW CENTERED IN THE SW NORTH ATLC NEAR 25N65W. WITH THE UPPER 
LEVEL TROUGHING EXPECTED TO MOVE LITTLE DURING THE NEXT 24 
HOURS...AN OVERALL DIFFLUENT ENVIRONMENT WILL REMAIN IN PLACE 
ACROSS HISPANIOLA WITH SCATTERED SHOWERS AND TSTMS FORECAST 
THURSDAY AFTERNOON INTO THE EVENING WITH PEAK DAYTIME HEATING 
AND INSTABILITY.

ATLANTIC OCEAN...                                              
AN UPPER LEVEL TROUGH IS OVER THE EASTERN CONUS REMAINING 
LARGELY N OF 31N THAT SUPPORTS A 1014 MB LOW CENTERED NEAR 
JACKSONVILLE FLORIDA WITH A STATIONARY FRONT EXTENDING EAST FROM 
THE LOW CENTER TO 30N77W THEN NE TO BEYOND 32N74W. ISOLATED 
SHOWERS ARE OCCURRING NW OF A LINE FROM 24N79W TO 32N72W TO THE 
FRONTAL BOUNDARY. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED 
NEAR 25N65W WITH MID-LEVEL ENERGY FOCUSED NEARLY IN THE SAME 
LOCATION THAT SUPPORTS AN AREA OF WIDELY SCATTERED SHOWERS AND 
ISOLATED TSTMS FROM 18N-28N BETWEEN 61W-70W. OTHERWISE...THE 
REMAINDER OF THE CENTRAL ATLC IS UNDER THE INFLUENCE OF A 
SURFACE RIDGE ANCHORED BY A 1027 MB HIGH CENTERED NEAR 38N57W. 
ON THE EASTERN PERIPHERY OF THIS RIDGE HOWEVER...A MIDDLE TO 
UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY WITH 
SHORTWAVE ENERGY LOCATED IN THE VICINITY OF 29N43W. AS THE 
SHORTWAVE MOVES E-SE...IT CONTINUES TO PRODUCE A BROAD AREA OF  
SCATTERED SHOWERS AND TSTMS FROM 28N-32N BETWEEN 44W-51W. THIS 
ACTIVITY REMAINS FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM A 
1016 MB LOW NEAR 34N32W SW TO ANOTHER 1016 MB LOW NEAR 30N42W 
WESTWARD TO 29N53W. OTHERWISE...THIS BROADER AREA OF LOWER 
PRESSURE IS ANALYZED E OF 50W WITH SKIES REMAINING MOSTLY FAIR.

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

$$
HUFFMAN