[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUL 31 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
2345 UTC.

...SPECIAL FEATURE...
A TROPICAL WAVE IS SW OF THE CAPE VERDE ISLANDS ALONG 27W
SOUTH OF 15N. THIS WAVE IS EMBEDDED WITHIN AN AREA OF A HIGH
AMPLITUDE MOISTURE MAXIMUM. A WELL DEFINED LOW TO MID LEVEL
CYCLONIC FLOW SURROUNDS THE WAVE AXIS EVIDENT ON INFRA RED
SATELLITE DATA. WHILE AMPLE MOISTURE IS NOTED IN THE LOW
LEVELS...A SAHARAN AIR LAYER IS PREVENTING ANY SIGNIFICANT
CONVECTION IN ASSOCIATION WITH THE WAVE. THEREFORE...MOST OF THE
CONVECTION NEAR BY THIS SYSTEM IS DUE TO INTERACTION WITH AN
ELONGATED AREA OF LOW PRESSURE EMBEDDED IN THE ITCZ. ALTHOUGH
THIS ENTIRE AREA OF DISTURBED WEATHER REMAINS
DISORGANIZED...SHOWER AND THUNDERSTORM ACTIVITY HAS INCREASED
DURING THE DAY.  CONDITIONS APPEAR FAVORABLE FOR SOME SLOW
DEVELOPMENT AS THE DISTURBANCE MOVES SLOWLY WESTWARD...AND THERE
IS A MEDIUM CHANCE OF TROPICAL CYCLONE FORMATION DURING THE NEXT
48 HOURS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS ALONG 53W S OF 18N MOVING W AT 10-15 KT.
WEAK CYCLONIC FLOW IS IN THE VICINITY OF THE WAVE NOTED ON
SATELLITE DERIVED WINDS. THE WAVE AXIS COINCIDES WITH A
MID-LEVEL TROUGH AXIS THAT CONTINUES TO GENERATE SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION FROM 8N TO 13N BETWEEN
50W AND 58W.

TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN SEA EXTENDING ALONG
17N72W TO 10N76W MOVING W 5-10 KT. THE WAVE REMAINS EMBEDDED
WITHIN AN AREA OF MAXIMUM TOTAL PRECIPITABLE WATER. VERY WEAK
LOW-LEVEL CYCLONIC TURNING IS NOTED ON VISIBLE SATELLITE
IMAGERY. HOWEVER...BROAD AREA OF UPPER LEVEL CYCLONIC
CIRCULATION NOTED ON WATER VAPOR IMAGERY IS GIVING SUPPORT TO
THE TROPICAL WAVE PRODUCING SCATTERED MODERATE TO ISOLATED
STRING CONVECTION BETWEEN 66W AND 80W.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 13N16W 10N28W 8N40W 7N50W. A SURFACE
LOW/TROUGH IS EMBEDDED IN THE ITCZ FROM 06N TO 12N ALONG 36W
WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION COVERING
A LARGE AREA FROM 4N TO 12N BETWEEN 25W AND 50W. MODERATE TO
STRONG CONVECTION IS WITHIN 60 NM OFF THE COAST OF SENEGAL...THE
GAMBIA AND GUINEA-BISSAU.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE 1007 MB LOW IS OVER THE NORTHERN FLORIDA PENINSULA
NEAR 30N82W. ALTHOUGH THE CONVECTION GENERATED BY THIS SYSTEM IS
MOSTLY INLAND...A FEW SHOWERS AND ISOLATED THUNDERSTORMS ARE
REACHING THE FLORIDIAN COAST FROM CEDAR KEY TO MIRAMAR BEACH.
ALSO...A SURFACE TROUGH ASSOCIATED WITH THE SURFACE LOW EXTENDS
FROM THE FLORIDA BIG BEND INTO THE GULF ALONG 30N84W TO 23N90W.
ISOLATED SHOWERS AND TSTMS ARE OCCURRING WEST OF THE SURFACE
TROUGH FROM 24N-28N BETWEEN THE SURFACE TROUGH AND 91W.
ELSEWHERE ACROSS THE REMAINDER OF GULF...DRY/STABLE AIR ALOFT IS
NOTED ON WATER VAPOR IMAGERY. A 1015 MB HIGH IS CENTERED OVER
THE WESTERN GULF NEAR 24N95W KEEPING FAIR WEATHER CONDITIONS
OVER THIS REGION WEST OF 91W.

CARIBBEAN SEA...
SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND THUNDERSTORMS OVER
MOST OF THE CENTRAL CARIBBEAN SEA BETWEEN 66W AND 80W. THE
ACTIVITY IS ASSOCIATED WITH A BROAD AREA OF UPPER LEVEL CYCLONIC
CIRCULATION NOTED ON WATER VAPOR IMAGERY...GIVING SUPPORT TO A
TROPICAL WAVE WITH AXIS FROM 17N72W TO 10N76W. SCATTERED SHOWERS
AND TSTMS ARE OCCURRING OVER THE SW CARIBBEAN S OF 12N W OF
75W...INCLUDING PORTIONS OF PANAMA AND COSTA RICA...DUE TO CLOSE
PROXIMITY OF THE ITCZ AXIS ALONG 10N. THE PRESENCE OF A SAHARAN
AIR LAYER ROUGHLY LOCATED FROM 850 MB TO 600 MB OVER THE FAR
EAST CARIBBEAN...IS PROVIDING STABLE AIR AND GENERALLY CLEAR
SKIES OVER PUERTO RICO...AND THE LEEWARD ISLANDS THIS EVENING.

ATLANTIC OCEAN...
A BROAD UPPER LEVEL LONGWAVE/TROUGH IS OVER THE NORTHWEST ATLC
AREA OF DISCUSSION. THIS UPPER LEVEL FEATURE SUPPORTS A NEARLY
STATIONARY FRONT THAT ENTERS OUR REGION THROUGH 32N70W AND
CONTINUES WEST ALONG 29N76W 30N81W. AN AREA OF CONVERGENT
LOW-LEVEL WINDS IS ALSO LOCATED 100 NM SOUTHEAST OF THE FRONT
DEPICTED AS A SURFACE TROUGH FROM FROM THE NORTHERN BAHAMAS NEAR
25N TO 29N. THE COMBINATION OF THESE SURFACE FEATURES ARE
GENERATING SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WEST
OF 64W NORTH OF 25N. THE LEADING EDGE OF THE UPPER LEVEL FEATURE
IS GENERATING STRONG UPPER LEVEL DIFFLUENCE FLOW...FURTHER
SUPPORTING THE CONVECTIVE WEATHER IN THIS REGION. THE REMAINDER
OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF
SURFACE RIDGING ANCHORED BY A 1032 MB HIGH CENTERED WELL NORTH
OF THE DISCUSSION AREA NEAR 45N31W. ALSO...DRY SAHARAN AIR
EMBEDDED IN THE BROAD UPPER LEVEL RIDGE OF HIGH PRESSURE IS
FURTHER KEEPING CONDITIONS FAIR ACROSS THIS REGION.

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

$$

GARCIA



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