[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071742
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON AUG 07 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
1700 UTC.

...SPECIAL FEATURE...
A 1009 MB ATLANTIC OCEAN LOW PRESSURE CENTER IS NEAR 12N40W...OR
ABOUT 1100 NM EAST OF THE SOUTHERN WINDWARD ISLANDS...MOVING
WEST NEAR 15 KT. ALTHOUGH THUNDERSTORM ACTIVITY IS CURRENTLY
LIMITED...ENVIRONMENTAL CONDITIONS APPEAR SOMEWHAT FAVORABLE FOR
FURTHER DEVELOPMENT AND A TROPICAL DEPRESSION COULD FORM LATER
TODAY OR TOMORROW.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 23W SOUTH OF 19N MOVING
WEST 10 TO 15 KT. THE EXACT POSITION OF THIS WAVE IS BECOMING
DIFFICULT TO LOCATE AS IT BECOMES SUPERIMPOSED UPON THE MONSOON
TROUGH...THOUGH BROAD CYCLONIC CURVATURE IS STILL OBSERVED ABOUT
THE AXIS. THE SURFACE LOW THAT WAS PREVIOUSLY ANALYZED ALONG THE
WAVE IS NO LONGER EVIDENT FROM THIS MORNINGS SATELLITE
ANIMATIONS. HOWEVER...A SMALL SWIRL OF LOW CLOUDS WAS NOTED ON
VISIBLE IMAGERY ABOUT 230NM W OF THE AXIS NEAR 14N19W. THIS
SMALL VORTICITY MAXIMUM SEEMS TO BE WEAKENING SINCE 12Z THOUGH.
SHOWER AND TSTM ACTIVITY IS MOSTLY ISOLATED WITHIN 250NM OF
EITHER SIDE OF THE AXIS...WITH A SMALL PATCH OF MODERATE
CONVECTION NOTED FROM 7N TO 10N BETWEEN 23W AND 27W. THIS MAY BE
MORE ASSOCIATED WITH THE ITCZ THOUGH.

AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 67W/68W SOUTH OF
23N MOVING WEST 15 TO 20 KT. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS EXTENDING NORTH FROM PUERTO RICO...THE MONA
PASSAGE...AND ERN HISPANIOLA FROM 16N TO 24N BETWEEN 66W AND
72W. MUCH OF THE WESTERN PORTION OF THIS WAVE THAT LIES IN THE
CARIBBEAN IS SHOWER/TSTM FREE DUE TO EXTENSIVE DRY AIR AND DENSE
SAHARAN DUST IN THE VICINITY.

 ...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 14N17W 12N21W 12N26W 11N36W 11N46W
TO THE SOUTH AMERICAN COAST NEAR 9N61W. SCATTERED SHOWER AND
TSTMS WITH EMBEDDED ISOLATED MODERATE CONVECTION LIES MAINLY
SOUTH OF THE AXIS FROM 3N TO 12N BETWEEN THE AFRICAN COAST AND
35W. ONLY ISOLATED SHOWERS AND TSTMS ARE NOTED W OF 35W THROUGH
THE S AMERICAN COAST. A SMALL PATCH OF MODERATE CONVECTION IS
MOVING INTO THE SOUTHERN CARIBBEAN SEA OFF THE N COAST OF
PANAMA...NORTH OF THE PORTION OF THE AXIS THAT EXTENDS INTO THE
E PACIFIC.

...DISCUSSION...
THE GULF OF MEXICO...
A SURFACE TROUGH...THE REMNANTS OF T.D. CHRIS...IS OVER THE
CENTRAL GULF OF MEXICO ALONG 28N89W 22N89W. ISOLATED SHOWERS AND
TSTMS ARE SPOTTING THE AREA FROM 22N TO THE GULF COAST BETWEEN
87W AND 93W. THE OTHER AREA OF UNSETTLED WEATHER IN THE GULF IS
LOCATED IN THE WESTERN BAY OF CAMPECHE WHERE SCATTERED
SHOWERS/TSTMS WITH ISOLATED MODERATE CONVECTION LIES FROM 18N TO
24N BETWEEN 93W AND 98W. AN OUTFLOW BOUNDARY IS SEEN ON VISIBLE
IMAGERY MOVING RADIALLY OUTWARD FROM THE N/NE PORTION OF THIS
CONVECTION. THIS ACTIVITY SEEMS TO BE ASSOCIATED WITH UPPER
DIFFLUENT AIR BETWEEN UPPER ANTICYCLONIC MOTION IN THE
VICINITY...ALONG WITH SOME WEAK SURFACE TROUGHING AS ANALYZED IN
THE 15Z MAP. WV IMAGERY SHOWS BROAD EASTERLY FLOW BLANKETING
MUCH OF THE GULF THIS AFTERNOON...ON THE SOUTH SIDE OF THE UPPER
HIGH CENTERED NEAR HUNTSVILLE ALABAMA. SOME WEAK SURFACE
TROUGHING MAY PERSIST IN THE FAR SW GULF OVER THE NEXT 24 TO
48HRS WHILE THE SHOWERS/TSTMS ASSOCIATED WITH THE
TROUGH/REMNANTS OF CHRIS MOVE W TOWARDS S TEXAS.
OTHERWISE...5-15KT E/SE WINDS WILL DOMINATE ON THE W/SW PORTION
OF THE ATLANTIC HIGH.

THE CARIBBEAN SEA...
AN UPPER LEVEL HIGH IS CENTERED OVER THE NORTHERN LEEWARD
ISLANDS THIS AFTERNOON. UPPER DIFFLUENT AIR BETWEEN THIS FEATURE
AND UPPER TROUGHING TO ITS EAST...NAMELY FROM S OF JAMAICA
EXTENDING NE OF THE BAHAMAS...IS INTERACTING WITH THE TROPICAL
WAVE IN THE AREA TO GENERATE THE MODERATE CONVECTION THAT IS
EXTENDING N THROUGH THE CARIBBEAN WATERS JUST S OF PUERTO RICO
AND HISPANIOLA. ISOLATED SHOWERS AND THUNDERSTORMS LIE E OF THE
TROPICAL WAVE AXIS ALONG 68W...FROM 11N TO 17N BETWEEN 61W AND
68W. MUCH OF THE CENTRAL CARIBBEAN WATERS W OF THIS AREA IS
UNDER THE INFLUENCE OF VERY DRY AIR...FAIR WEATHER...AND DENSE
AFRICAN DUST AS ANALYZED ON THE 12Z UW-CIMSS SAHARAN LAYER
ANALYSIS. THE EXCEPTION IS THE NW CARIBBEAN ESPECIALLY BETWEEN
JAMAICA AND WRN CUBA WHERE SCATTERED MODERATE CONVECTION
LIES...ANOTHER UPPER DIFFLUENT AREA BETWEEN THE UPPER LOW NEAR
THE BAHAMAS AND THE EASTERLY FLOW ON THE S PORTION OF THE UPPER
HIGH OVER THE SE US. AT THE SURFACE...15 TO 25 KT TRADE FLOW
DOMINATES ON THE S/SW PORTION OF THE ATLANTIC HIGH. THIS
MORNINGS QUIKSCAT PASS DID SHOW SLIGHTLY STRONGER 30 KT WINDS
JUST OFF THE COLOMBIAN COAST AS THE HIGH INTERACTS WITH THE
COLOMBIAN LOW. THIS IS EXPECTED TO PERSIST OVER THE NEXT COUPLE
OF DAYS...THOUGH THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVE WILL MOVE W BRINGING SHOWERS/TSTMS...LOCALLY HEAVY AT
TIMES...TO HISPANIOLA...JAMAICA...CUBA...AND THE BAHAMAS.

THE ATLANTIC OCEAN...
UPPER LEVEL NE/ENE FLOW IS HOVERING OVER FLORIDA AND THE
ADJACENT ATLC WATERS THIS AFTERNOON BETWEEN THE UPPER HIGH OVER
NRN ALABAMA AND THE UPPER LOW JUST E OF THE BAHAMAS. THE NRN
PORTION OF THE TROPICAL WAVE EXTENDING THROUGH THE MONA PASSAGE
IS COMBINING WITH UPPER DIFFLUENT AIR TO GENERATE A CLUSTER OF
MODERATE CONVECTION IN THE SW ATLC JUST E OF THE TURKS AND
CAICOS. SEE TROPICAL WAVE SECTION ABOVE FOR MORE INFO. AN UPPER
HIGH IS LOCATED OVER THE NRN LEEWARD ISLANDS. JUST TO THE ENE
LIES AN UPPER LOW CENTERED NEAR 22N54W. THIS LOW IS STRUGGLING
TO FIND MOISTURE WITH A BROAD AREA OF DRY AIR AND SAHARAN DUST
IN THE VICINITY. UPPER CYCLONIC MOTION IS ALSO SEEN FROM 23N TO
30N BETWEEN 36W AND 50W...AND EXTENDING FURTHER N OUT OF THE TPC
TAFB AREA OF RESPONSIBILITY. BROAD ANTICYCLONIC FLOW IS SEEN IN
THE FAR ERN ATLC WITH AN UPPER HIGH EXTENDING OFF THE W AFRICAN
COAST TO NEAR 35W. AT THE SFC ASIDE FROM THE SPECIAL FEATURES
AND TROPICAL WAVE...5-15KT E FLOW DOMINATES MUCH OF THE AREA ON
THE S/SW SIDE OF A 1029MB HIGH ANALYZED NEAR 43N26W. ANOTHER
1024MB SFC HIGH IS LOCATED NEAR 28N64W. A NON-TROPICAL LOW IS
LOCATED ABOUT 700 MILES WEST-SOUTHWEST OF THE AZORES.  SHOWER
ACTIVITY WITH THIS SYSTEM IS DISORGANIZED AND DEVELOPMENT...IF
ANY...IS EXPECTED TO BE SLOW TO OCCUR.

$$
WILLIS


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