[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 061802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 06 2005

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

...SPECIAL FEATURES...

TROPICAL STORM DENNIS CENTERED NEAR 15.7N 72.0W OR ABOUT 350
MILES ESE OF KINGSTON JAMAICA AT 06/1800 UTC MOVING WNW 12 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE 991 MB. MAXIMUM SUSTAINED
WIND SPEED 60 KT GUSTS TO 75 KT. SEE LATEST NHC PUBLIC ADVISORY
UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AND FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE
DETAILS. THE SATELLITE REPRESENTATION OF DENNIS SHOWS TWO
WELL-DEFINED CONVECTIVE BANDS...ONE OVER THE E SEMICIRCLE WITHIN
150 NM OF THE CENTER AND THE OTHER WITHIN 90 NM S SEMICIRCLE.
NUMEROUS MODERATE/STRONG CONVECTION IS FROM 12N-19N BETWEEN
67W-77W. MOST OF THE HEAVY RAINS ARE CURRENTLY OVER THE OPEN
WATERS OF THE CARIBBEAN...BUT SOME OF THE SPIRAL BANDS ARE
BEGINNING TO SPREAD ALONG THE SRN COAST OF HISPANIOLA. THE
STRONGEST CONVECTIVE BURST IS CURRENTLY NE OF THE CENTER DUE TO
AN OUTFLOW JET EMANATING FROM THE NE QUADRANT TO THE SE...AND IF
THIS CLUSTER MOVES TO THE N/NW IT COULD PRODUCE VERY HEAVY RAINS
AND FLOODING OVER THE MOUNTAINS OF HAITI AND THE DOMINICAN
REPUBLIC. DENNIS IS EXPECTED TO INTENSIFY TO HURRICANE STRENGTH
LATER TODAY OR TONIGHT AND WILL BE APPROACHING JAMAICA TOMORROW
MORNING. THE HEAVY RAINS WILL SPREAD OVER JAMAICA AND ERN CUBA
LATER THIS EVENING AND THEN ACROSS THE REST OF CUBA AND THE
CAYMAN ISLANDS ON THU.

TROPICAL DEPRESSION CINDY CENTERED NEAR 31.4N 88.4W OR ABOUT 50
MILES NNW OF MOBILE ALABAMA AT 06/1500 UTC MOVING NE 12 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB. MAXIMUM SUSTAINED
WIND SPEED 30 KT GUSTS TO 40 KT. SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE
DETAILS. THIS IS THE FINAL ADVISORY ISSUED BY THE NATIONAL
HURRICANE CENTER...AND ALL FUTURE ADVISORIES ON CINDY WILL BE
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER IN
WASHINGTON DC. RADAR IMAGERY INDICATES THAT THE RAIN SHIELD
ASSOCIATED WITH CINDY IS N OF THE CENTER WITH NUMEROUS
SHOWERS/TSTMS ACROSS CNTRL ALABAMA FROM 32N-35N BETWEEN
86W-89W...WITH A TAIL OF SCATTERED TSTMS EXTENDING SW OF THE
FLORIDA PANHANDLE INTO THE CNTRL GULF. THE WINDS NEAR THE CENTER
WILL CONTINUE TO WEAKEN BUT HEAVY RAINS ARE EXPECTED TO SPREAD
NEWD ACROSS THE SOUTHERN APPALACHIANS...MID-ATLC...AND NEW
ENGLAND THROUGH SAT.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE IS LOCATED IN THE VICINITY OF 30W S
OF 23N. UPPER AIR SOUNDINGS FROM DAKAR AND SAL SHOW WAVE PASSAGE
NEAR 18Z JUL 3 AND 18Z JUL 4...RESPECTIVELY...WHICH SUPPORTS A
SLOW WWD TRANSLATION OF 5-10 KT. THE WAVE PRESENTS A COMPLEX
STRUCTURE AT THE MOMENT. MET-7 VISIBLE IMAGERY SHOWS A STRONG
LOW-LEVEL CIRCULATION ABOUT 200 NM SW OF THE CAPE VERDES...WHICH
IS SUPPORTED BY QUIKSCAT IMAGERY...BUT THE MID-LEVEL SIGNATURE
(WHICH WE HAVE BEEN TRACKING) IS NOTED IN INFRARED IMAGERY ABOUT
300 NM TO THE E NEAR 32W. THE SURFACE ANALYSIS AT 1800 UTC WILL
SHOW A COMPROMISE OF THESE POSITIONS BUT MOST LIKELY THE
MID-LEVEL FEATURE WILL BECOME THE DOMINANT AXIS. CONVECTION IS
ALIGNED ALONG THE ITCZ.

WEAK TROPICAL WAVE REPOSITIONED FARTHER E ALONG 55W S OF 11N
MOVING W 15 KT. THE LOW-LEVEL WINDS BELOW 800 MB SWITCHED FROM
NELY TO LIGHT SELY OVERNIGHT WHICH INDICATES WAVE PASSAGE.
QUIKSCAT IMAGERY ALSO INDICATED WEAK CURVATURE TO THE SFC FLOW
JUST N OF THE GUIANAS. IN ADDITION...THE PREVIOUS WAVE POSITION
WAS LOCATED W OF BARBADOS...AND THE UPPER AIR SOUNDING FROM THIS
MORNING SHOWED BACKING (NOT VEERING) WINDS WHICH PROBABLY
INDICATES THAT THE WAVE IS APPROACHING. CONVECTION IS E OF THE
WAVE NEAR THE ITCZ.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N10W 11N17W 6N35W 8N45W 8N53W...
THEN OVER S AMERICA. NUMEROUS MODERATE/STRONG CONVECTION
ASSOCIATED WITH A WEST AFRICAN DISTURBANCE LINE THAT MOVED OFF
THE AFRICAN COAST FROM 7N-12N BETWEEN 14W-24W. SCATTERED
MODERATE WITHIN 90 NM OF THE AXIS BETWEEN 26W-38W. SCATTERED
MODERATE FROM 6N-10N BETWEEN 46W-56W.

...DISCUSSION...

GULF OF MEXICO...
TROPICAL STORM CINDY MADE LANDFALL JUST BEFORE 11 PM LOCAL TIME
NEAR GRAND ISLE LOUISIANA AND HAS SINCE WEAKENED TO TROPICAL
DEPRESSION STATUS AS IT CROSSES FROM MISSISSIPPI INTO ALABAMA.
THE WEATHER OVER THE GULF OF MEXICO AREA IS QUICKLY CLEARING
BEHIND CINDY AS DRY AIR IN THE MID/UPPER LEVELS PUNCHES IN FROM
THE W/NW...AND A FAIRLY DRY AIR MASS MOVES IN FROM THE E. AN
UPPER LEVEL HIGH CENTERED JUST W OF FLORIDA NEAR 27N85W WITH
RIDGE EXTENDING FROM CNTRL FLORIDA TO THE BAY OF CAMPECHE IS
REINFORCING THIS CLEARING WEATHER. HOWEVER...A ZONE OF LOW-LEVEL
CONVERGENCE OVER THE CNTRL GULF HAS CREATED A TAIL OF
SHOWERS/TSTMS S OF CINDY WITH SCATTERED MODERATE CONVECTION
WITHIN 30 NM OF A LINE FROM 23N92W TO 30N86W OVER THE FL
PANHANDLE. ANOTHER SMALL PATCH OF SHOWERS IS LOCATED ALONG THE
MEXICAN COAST JUST S OF VERACRUZ. DRY AIR WILL CONTINUE TO
FILTER INTO THE AREA OVER THE NEXT 24-36 HRS WHICH WILL DECREASE
THE TSTM THREAT. THE NEXT CONCERN WILL BE TROPICAL STORM DENNIS
WHICH IS FORECAST TO MOVE INTO THE SE GULF FRI AND SAT WITH
INCREASING SHOWERS/TSTMS IN SQUALLS.

CARIBBEAN...
OF COURSE THE MAIN CONCERN OVER THE CARIBBEAN AT THE MOMENT IS
THE FUTURE OF TROPICAL STORM DENNIS. THE SYSTEM CONTINUES TO
ORGANIZE AND IS EXPECTED TO REACH HURRICANE STRENGTH LATER TODAY
OR TONIGHT AS IT APPROACHES JAMAICA...HAITI...E CUBA...AND THE
CAYMAN ISLANDS. SEE SPECIAL FEATURES FOR FURTHER DISCUSSION.
ELSEWHERE THE WEATHER IS FAIRLY NICE. DRY AIR ALOFT IS LOCKED IN
AHEAD OF DENNIS' PATH OVER THE NW CARIBBEAN AND IS PRODUCING
MOSTLY CLEAR SKIES W OF 78W. ONLY A FEW ISOLATED TSTMS ARE NOTED
OFF THE COAST OF NICARAGUA AND E PANAMA. THE E CARIBBEAN/LESSER
ANTILLES ARE CLEARING UP BEHIND DENNIS WITH MOSTLY HIGH CLOUDS
NOTED OVER THE NRN LEEWARD ISLANDS...AND A FEW OUTER EDGES OF
THE SPIRAL BANDS NEAR PUERTO RICO AND THE VIRGIN ISLANDS.

ATLANTIC...
UPPER LEVEL RIDGE EXTENDS ACROSS CNTRL FLORIDA NEWD TO NEAR
31N73W AS A SHORTWAVE TROF DIGS DOWN FARTHER E JUST S OF
BERMUDA. A COLD FRONT IS BEING PUSHED SWD BY THE SHORTWAVE TO
ALONG 32N58W 30N63W 30N67W WITH SCATTERED MODERATE CONVECTION N
OF 28N BETWEEN 57W-63W. AN UPPER LOW IS LOCATED S OF
SHORTWAVE...AND JUST NE OF THE NRN LEEWARD ISLANDS...NEAR 21N55W
BUT THE ADJACENT AREA IS COVERED BY SO MUCH DRY AIR THAT THERE
IS LITTLE ACTIVE WEATHER. THE UPPER LOW IS CONNECTED TO A SECOND
UPPER LOW NEAR THE AZORES BY A WEAK TROF/SHEAR AXIS WHICH MARKS
THE NRN EDGE OF AN AREA OF STRONG SUBSIDENCE OVER THE E ATLC
WATERS. DRY AIR EXTENDS INTO THE LOW-LEVELS AND REACHES ACROSS
THE ENTIRE ATLC TO THE LESSER ANTILLES...CHARACTERIZED BY STABLE
CONDITIONS WITH FLAT STRATOCU. THE SUBTROPICAL RIDGE LIES
ROUGHLY ALONG 27N60W 32N43W WITH LIGHT EASTERLY TRADES TO THE
S.

$$
BERG


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