[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 13 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURE...
A TROPICAL WAVE IS GENERATING SHOWERS AND A FEW THUNDERSTORMS
OVER THE WINDWARD ISLANDS. THIS WAVE IS ACCOMPANIED BY A 1012MB
SURFACE LOW NEAR 13N58W. THIS SYSTEM HAS BECOME A LITTLE BETTER
ORGANIZED TODAY AND SOME ADDITIONAL DEVELOPMENT IS POSSIBLE
DURING THE NEXT COUPLE OF DAYS AS IT MOVES WEST-NORTHWESTWARD AT
10 TO 15 KT.  AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS
SCHEDULED TO INVESTIGATE THE SYSTEM THIS AFTERNOON. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION LIES FROM 11N TO 18N BETWEEN
55W AND 64W.

...TROPICAL WAVES...
TROPICAL WAVE OFF THE W COAST OF AFRICA IS ALONG 23W S OF 18N
MOVING W 10-15 KT. THE CLASSIC INVERTED V PATTERN ASSOCIATED
WITH THIS WAVE IS MUCH MORE EVIDENT IN TODAYS LOW CLOUD MOTIONS
THAN 24 HOURS AGO. CONVECTION ASSOCIATED WITH THIS WAVE REMAINS
LIMITED ASIDE FROM THE SCATTERED SHOWERS AND TSTMS IN THE
VICINITY OF THE ITCZ. ONLY ISOLATED SHOWERS/TSTMS LIE ELSEWHERE
WITHIN 200NM OF EITHER SIDE OF THE AXIS.

TROPICAL WAVE IN THE WRN CARIBBEAN IS ALONG 83W/84W S OF 20N
MOVING W NEAR 15-20 KT. PATCHES OF SCATTERED MODERATE CONVECTION
LIE FROM THE SW CARIBBEAN THROUGH ERN CENTRAL AMERICA AND INTO
THE GULF OF HONDURAS. THIS MAY ALSO BE ASSOCIATED WITH
INSTABILITY AROUND THE BASE OF THE UPPER TROUGH IN THE
REGION...ALONG WITH UPSLOPE FLOW OVER THE CENTRAL AMERICAN
TERRAIN.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N17W 11N22W 10N26W 11N55W 11N55W
TO NEAR THE NE VENEZUELAN COAST NEAR 10N65W. SCATTERED MODERATE
CONVECTION LIES FROM 6N TO 11N BETWEEN 24W AND 34W. ANOTHER AREA
OF SCATTERED MODERATE CONVECTION IS OFF THE NE SOUTH AMERICAN
COAST...MAINLY SOUTH OF THE AXIS...FROM 4N TO 10N BETWEEN 44W
AND 55W. ONLY ISOLATED SHOWERS AND TSTMS ARE NOTED ELSEWHERE IN
THE VICINITY OF THE AXIS.

...DISCUSSION...
GULF OF MEXICO...
WEATHER ACROSS THE GULF FOR THE MOST PART CONTINUES TO BE FAIRLY
QUIET WITH ONLY A COUPLE OF EXCEPTIONS IN THE EXTREME SW AND NE
PORTIONS. A CLUSTER OF MODERATE CONVECTION LIES IN THE FAR SW
BAY OF CAMPECHE AND INTO COASTAL MEXICO. THIS SEEMS TO BE
ASSOCIATED WITH LOW LEVEL UPSLOPE FLOW ALONG WITH UPPER
DIFFLUENT AIR BETWEEN AN UPPER HIGH OVER SE MEXICO AND THE UPPER
LOW SEEN SPINNING ABOUT 180NM W OF BROWNSVILLE TEXAS...WHICH
EXTENDS INTO THE WRN GULF. THE OTHER INTERESTING FEATURE IN THE
GULF IS A WEAK STATIONARY FRONT EXTENDING THROUGH THE NE
GULF...BUT ONLY ISOLATED SHOWERS ARE NOTED NEAR THIS
BOUNDARY...AT LEAST NEAR THE GULF PORTION WITH THE ATLC PORTION
A DIFFERENT STORY AS DISCUSSED BELOW. AN UPPER HIGH IS LOCATED
OVER SOUTH CENTRAL FLORIDA...WITH DRY AIR SEEN HOVERING OVER
MUCH OF THE REMAINDER OF THE ERN AND CENTRAL GULF. A 1017MB
SURFACE HIGH IS ANALYZED ABOUT 200NM SOUTH OF PENSACOLA WHICH IS
PRODUCING FAIRLY LIGHT WINDS ACROSS THE GULF. SLIGHTLY STRONGER
15KT SE FLOW OBSERVED IN THE WRN GULF AS THIS HIGH INTERACTS
WITH LOWER PRESSURE OVER MEXICO.

CARIBBEAN SEA...
TWO TROPICAL WAVES ARE AFFECTING THE CARIBBEAN...ONE ALONG 84W
AND THE OTHER MOVING INTO THE WINDWARD ISLANDS. CONVECTION
ASSOCIATED WITH THE LATTER IS PRODUCING SHOWERS AND TSTMS OVER
PORTIONS OF THE WINDWARD ISLANDS AND ADJACENT ERN CARIBBEAN
WATERS AS NOTED IN THE SPECIAL FEATURE. AN UPPER TROUGH
DOMINATES THE WRN GULF...WITH AN UPPER HIGH NEAR THE LEEWARD
ISLANDS EXTENDING WEST OVER THE CENTRAL AND ERN GULF. ASIDE FROM
THE FAR WRN AND FAR ERN CARIBBEAN NEAR THE TROPICAL WAVES...FAIR
WEATHER DOMINATES MUCH OF THE REMAINDER OF THE CARIBBEAN. 15 TO
25 KT TRADE FLOW DOMINATES WITH THE STRONGEST WINDS LIKELY JUST
NORTH OF THE COLOMBIAN COAST...AS THE S PORTION OF THE ATLC HIGH
INTERACTS WITH LOWER PRESSURE OVER COLOMBIA. SHOWERS AND TSTMS
ASSOCIATED WITH THE TROPICAL WAVE WILL MOVE THROUGH THE ERN
CARIBBEAN THROUGH MONDAY.

ATLANTIC OCEAN...
STRONG MID TO UPPER LEVEL TROUGH HAS PUSHED OFF THE EAST COAST
WITH ITS SOUTHERN MOST PORTION EXTENDING SOUTH TO NEAR 30N OFF
THE GEORGIA/NE FLORIDA COAST.  SURFACE HIGH PRESSURE HAS BUILT
INTO THE MID ATLANTIC STATES BRINGING VERY PLEASANT WEATHER. IN
THE REGION OF CONFLUENCE BETWEEN THIS HIGH AND THE ATLC HIGH TO
ITS SOUTH LIES A FRONTAL BOUNDARY THAT HAS NOW SAGGED TO NEAR
CAPE CANAVERAL AND EXTENDS ENE INTO THE ADJACENT ATLC WATERS. A
1012MB SURFACE LOW IS ALONG THIS FRONT NEAR 29N77W. THIS
NON-TROPICAL LOW PRESSURE SYSTEM IS PRODUCING A SMALL AREA OF
SHOWERS AND THUNDERSTORMS. SOME SLOW DEVELOPMENT OF THIS SYSTEM
IS POSSIBLE OVER THE NEXT COUPLE OF DAYS AS IT MOVES SLOWLY TO
THE SOUTHEAST OR SOUTH. AN UPPER RIDGE AXIS EXTENDS EAST FROM
CENTRAL FLORIDA TO NEAR 72W. AN UPPER TROUGH IS EXTENDING NE
THROUGH CUBA AND THE BAHAMAS INTO THE ADJACENT WATERS...BUT IS
NOT GENERATING MUCH SHOWER ACTIVITY. UPPER RIDGING DOMINATES THE
AREA FROM 10N TO 32N BETWEEN 52W AND 68W. A FEW SMALL/BENIGN
UPPER LOWS LIE E OF THIS AREA...NEAR 26N46W...25N36W AND THE
LAST NEAR 15N33W. AN UPPER HIGH OVER THE COAST OF W AFRICA
EXTENDS OUT TO NEAR 35W WITH THE AXIS ALONG 19N. OVERALL FAIR
WEATHER DOMINATES MUCH OF THE AREA OUTSIDE OF THE TROPICAL WAVES
AND FRONTAL BOUNDARY...WITH A 1021MB SURFACE HIGH ANALYZED NEAR
25N33W...AND THE RIDGE AXIS EXTENDING W THROUGH THE SRN BAHAMAS
AND INTO CUBA.

$$
WILLIS


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