000
AXNT20 KNHC 300004
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
805 PM EDT WED JUL 28 2010

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS MOVING OFF THE WEST COAST OF AFRICA EXTENDING
FROM 17N19W TO 8N15W MOVING W NEAR 10 KT. THE DAKAR SENEGAL 
UPPER AIR SOUNDING INDICATED THE WAVE PASSED THROUGH AT THE 
LOWER LEVELS ABOUT 18 HOURS AGO. WIDELY SCATTERED  MODERATE 
ISOLATED STRONG CONVECTION ARE WITHIN 120 NM EITHER SIDE OF THE 
WAVE AXIS FROM 10N-15N.

TROPICAL WAVE IS FROM 16N54W TO 8N60W MOVING W NEAR 20 KT. WAVE 
REMAINS TILTED N-NE/S-SW. S TO SW FLOW E OF THE WAVE AXIS HAS 
LIFTED THE ITCZ NORTHWARD TO NEAR 14N. DUE TO THE PRESENCE OF 
MID AND UPPER LEVEL CONVECTIVE DEBRIS CLOUDINESS PRESENT...
THE LOW LEVEL WAVE AXIS IS NOT EASILY RECOGNIZABLE ON SATELLITE 
IMAGERY. THE MOST RECENT UPPER AIR TIMESECTION FROM BARBADOS 
SUGGESTS THE WAVE AXIS REMAINS E OF THE STATION. 

TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN EXTENDS FROM 19N76W TO 
THE COAST OF COLOMBIA NEAR 10N76W MOVING W 15-20 KT. WAVE 
APPEARS TOP BE EMBEDDED WITHIN AN AREA OF INCREASINGLY DIFFLUENT
ANTICYCLONIC FLOW ALOFT WHICH HAS RESULTED IN AN AREA OF 
SCATTERED MODERATE TO STRONG CONVECTION ALONG AND TO THE W OF 
THE WAVE AXIS. 

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 11N18W 9N25W 8N29W 8N33W 13N53W 
11N64W. A SURFACE TROUGH AND ASSOCIATED 1010 MB LOW PRES 
IS CURRENTLY EMBEDDED WITHIN THE ITCZ NEAR 9N31W IS GENERATING 
SCATTERED MODERATE ISOLATED STRONG OF CONVECTION WITHIN 120 NM S 
OF THE AXIS BETWEEN 31W AND 41W. HOVMOELLER DIAGRAMS...LONG
TERM SATELLITE IMAGERY AND SPECTRAL ANALYSIS SUGGEST THAT THIS 
TROUGH IS ACTUALLY A TROPICAL WAVE AND WILL THEREFORE BE 
INTRODUCED ON THE 00 UTC SURFACE ANALYSIS. SCATTERED MODERATE TO 
STRONG CONVECTION IS NOTED WITHIN 120-180 NM N OF THE AXIS 
BETWEEN 45W AND 57W. 

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LOW AND INVERTED TROUGH EXTENDS FROM E TEXAS 
SOUTHWARD OVER THE W GULF ALONG 95W AND CONNECTS TO A FAIRLY 
LARGE UPPER LEVEL LOW ALONG THE MEXICAN-GUATEMALAN BORDER. THE 
TROUGH AND UPPER LEVEL LOW WERE MOVING W AT 15-20 KT. AN UPPER 
LEVEL ANTICYCLONE WAS CENTERED ALONG THE FLORIDA BIG BEND AND 
COVERED THE E GULF N OF 23N AND E OF 91W. DIFFLUENT UPPER LEVEL 
EASTERLY FLOW WAS AIDING IN THE MAINTENANCE OF STRONG 
THUNDERSTORMS OVER THE FLORIDA PENINSULA AND ALONG THE SW COAST 
OF FLORIDA. A SURFACE TROUGH EXTENDS ACROSS THE FLORIDA 
PENINSULA FROM JACKSONVILLE THROUGH MELBOURNE INTO THE GULF NEAR 
NAPLES. A SURFACE RIDGE DOMINATES MOST OF THE GULF WITH A 1023 
MB HIGH INLAND OVER SW LOUISIANA...AND ANOTHER 1022 MB HIGH NEAR 
28N91W.  

CARIBBEAN SEA...
A BROAD UPPER LOW W OF THE CARIBBEAN CENTERED ALONG THE 
MEXICAN-GUATEMALAN BORDER NEAR 18N91W WAS MOVING W 15-20 KT.
UPPER LEVEL DIFFLUENT FLOW E OF THE UPPER LOW AND WITHIN A 
WESTWARD EXPANDING UPPER LEVEL RIDGE/ANTICYCLONE NEAR 16N73W
WAS ENHANCING AREA OF SCATTERED MODERATE TO STRONG CONVECTION 
WITHIN 120 NM E AND W OF A TROPICAL WAVE ALONG 76W FROM 13N TO 
17N. ADDITIONAL SCATTERED SHOWERS/ISOLATED THUNDERSTORMS EXTEND 
FURTHER W OVER HONDURAS...GUATEMALA AND THE YUCATAN PENINSULA.
FURTHER E...NORTHWESTERLY UPPER LEVEL FLOW ON THE E SIDE OF 
THE ANTICYCLONE NOTED ABOVE IS SWEEPING ACROSS THE NE CARIBBEAN
TO THE N OF A NARROW RIDGE AXIS ALONG 14N AND ALSO ACROSS THE 
NORTHERN EXTENT OF THE TROPICAL WAVE APPROACHING FROM THE EAST.  

ATLANTIC OCEAN...
A STATIONARY FRONT IS ALONG THE N PERIPHERY OF THE W ATLC 
EXTENDING FROM A 1016 MB LOW NEAR 36N61W ACROSS BERMUDA TO 
32N71W WITH AREAS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
FROM 27N-33N BETWEEN 60W-78W. OTHERWISE...NO SIGNIFICANT WEATHER 
IS OCCURRING ACROSS THE REMAINDER OF THE ATLC BASIN. A SURFACE 
RIDGE DOMINATES THE ATLC ANCHORED BY A 1024 MB HIGH NEAR 32N48W 
ALONG 27N65W TO THE N BAHAMA ISLANDS NEAR 27N78W. LAST LOW LIGHT 
VISIBLE SATELLITE IMAGERY AND CIMSS SAHARAN AIR ANALYSES SHOWS 
YET ANOTHER SAHARAN AIR MASS SURGING INTO THE ATLC EAST OF 45W 
AND REMAINING ACROSS PORTIONS OF THE REMAINDER OF THE TROPICAL 
ATLC. 

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

$$
COBB