[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 061748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU OCT 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 DEPRESSION TAMMY IS CENTERED NEAR 31.7N 85.5W...OR
ABOUT 20 NM N OF DOTHAN ALABAMA...AT 06/1500 UTC MOVING W 10 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED
WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE
DETAILS. TAMMY HAS A VERY ASYMMETRICAL PRECIPITATION STRUCTURE
WITH THE HEAVIEST AND MOST CONTINUOUS RAIN BANDS LOCATED OVER
THE CAROLINAS ABOUT 220 NM NE OF THE CENTER. THE DEEPEST
CONVECTION IS LOCATED FROM THE ERN CAROLINAS SEWD OVER THE
WATERS E OF GEORGIA AND FLORIDA...WITH SCATTERED MODERATE FROM
22N-34N BETWEEN 72W-80W. WIDESPREAD LIGHT TO MODERATE RAIN IS
FALLING FROM COASTAL NORTH AND SOUTH CAROLINA WWD INTO ERN
TENNESSEE WHILE ONLY MORE SCATTERED SHOWERS/TSTMS EXTEND OVER
FLORIDA...GEORGIA...AND ALABAMA. THIS IS THE LAST ADVISORY
ISSUED BY THE NATIONAL HURRICANE CENTER...AND FUTURE ADVISORIES
WILL BE ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER.

AN AREA OF LOW PRES...1010 MB...IS CENTERED OVER THE CENTRAL
ATLANTIC ABOUT 1150 NM ESE OF THE LESSER ANTILLES NEAR 9N42W AND
IS ASSOCIATED WITH A TROPICAL WAVE ALONG 42W S OF 15N WHICH IS
MOVING W 10-15 KT. THE SURFACE CIRCULATION AROUND THE LOW IS NOT
VERY WELL-DEFINED AT THE MOMENT ALTHOUGH THERE IS A MID-LEVEL
CIRCULATION NOTED NEAR 8N43W. THE WAVE HAS A SHARP SIGNATURE AND
MOST OF THE LOW-LEVEL CONVERGENCE IS LOCATED N OF THE LOW ALONG
THIS AXIS. SCATTERED MODERATE CONVECTION IS FROM 10N-16N BETWEEN
38W-45W. WIDELY SCATTERED SHOWERS/TSTMS ELSEWHERE FROM 4N-10N
BETWEEN 36W-46W. TROPICAL CYCLONE DEVELOPMENT IS POSSIBLE WITHIN
THE NEXT 24 HRS WITH THIS SYSTEM...ESPECIALLY IF CONVECTION
CONSOLIDATES CLOSER TO THE LOW CENTER OR A NEW LOW DEVELOPS
WITHIN THE STRONGEST CONVECTION.

...TROPICAL WAVES...

SEE SPECIAL FEATURES FOR TROPICAL WAVE/LOW ALONG 42W.

EAST CARIBBEAN TROPICAL WAVE ALONG 66W S OF 18N MOVING W 10-15
KT. THE WAVE HAS SLIGHT CURVATURE TO THE LOW-LEVEL FLOW AND IS
LOCATED NEAR A CLUSTER OF TSTMS EXTENDING S OF PUERTO RICO AND
HISPANIOLA. WIDELY SCATTERED MODERATE CONVECTION FROM 14N-20N
BETWEEN 65W-72W.

...ITCZ...

ITCZ IS CENTERED ALONG 13N12W 7N28W 11N40W...THEN EXTENDING FROM
COLOMBIA NWWD ACROSS CENTRAL AMERICA. WIDELY SCATTERED MODERATE
CONVECTION WITHIN 120 NM OF THE AXIS BETWEEN 15W-21W. WIDELY
SCATTERED SHOWERS/TSTMS FROM 2N-7N BETWEEN 22W-37W.

...DISCUSSION...

NORTHERN MEXICO...
A STRONG COLD FRONT MOVED ACROSS THE U.S.-MEXICO BORDER EARLIER
THIS MORNING AND NOW EXTENDS FROM DEL RIO TEXAS TO S OF
CHIHUAHUA MEXICO THEN TO TUCSON ARIZONA. WIDESPREAD STRATUS AND
ISOLATED SHOWERS/TSTMS EXTEND N OF THE FRONTAL BOUNDARY INTO W
TEXAS AND ERN NEW MEXICO.

GULF OF MEXICO...
A COMPLEX PATTERN HAS EVOLVED OVER THE GULF WATERS AND IS
CAUSING WET WEATHER EXTENDING FROM SRN MEXICO TO W CUBA THEN NWD
ACROSS MOST OF FLORIDA. A NEARLY STATIONARY UPPER LEVEL TROUGH
IS LOCATED ALONG 88W...WITH AN EMBEDDED UPPER LOW NEAR
27N88W...AND IS DRAWING EXTENSIVE TROPICAL MOISTURE FROM CENTRAL
AMERICA NWD INTO THE SOUTHEAST UNITED STATES. T.D. TAMMY HAS
ROTATED NWWD INTO SE ALABAMA AND A SURFACE TROUGH HAS DEVELOPED
WHICH EXTENDS FROM TAMMY SW TO A 1005 MB LOW N OF THE YUCATAN
COAST NEAR 23N89W...THEN W TO NEAR VERACRUZ MEXICO. SCATTERED
SHOWERS/TSTMS HAVE DEVELOPED ALONG THE TROUGH OVER THE NE GULF
FROM 26N-31N BETWEEN 83W-87W...AND SCATTERED MODERATE CONVECTION
IS ALSO EXTENDS FROM VERACRUZ INTO THE BAY OF CAMPECHE FROM
18N-21N BETWEEN 92W-97W. MUCH DRIER AIR HAS FILTERED IN BEHIND
THE TROUGH LEAVING MOSTLY FAIR SKIES OVER THE CENTRAL/W GULF.
ANOTHER AREA OF CONCERN IS A 1004 MB LOW CENTERED NEAR THE W TIP
OF CUBA NEAR 22N85W. ALTHOUGH THIS FEATURE IS PRODUCING STRONG
CONVECTION OVER THE NW CARIBBEAN AND WILL LIKELY DRAG THIS
MOISTURE NWD TOWARDS FLORIDA OVER THE NEXT 24 HRS...CONDITIONS
NO LONGER LOOK AS FAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT.
SOME OF THE MOISTURE AHEAD OF THE LOW IS ALREADY PRODUCING
SCATTERED SHOWERS/TSTMS OVER FLORIDA AND THE STRAITS OF FLORIDA.

CARIBBEAN...
THE 1004 MB LOW NEAR THE W TIP OF CUBA AND THE SHARP UPPER
TROUGH OVER THE GULF OF MEXICO IS INDUCING A LARGE AREA OF
NUMEROUS STRONG CONVECTION JUST W OF THE CAYMAN ISLANDS FROM
17.5N-22N BETWEEN 82W-86W...SOMEWHAT IN THE STRUCTURE OF A
SQUALL LINE. SCATTERED MODERATE/STRONG CONVECTION ALSO EXTENDS E
OF THIS AREA OVER E CUBA AND JAMAICA FROM 16N-20N BETWEEN
75W-82W. ALL THIS ACTIVITY IS BEING FED BY A DEEP POOL OF
TROPICAL MOISTURE OVER THE NW CARIBBEAN WHICH IS EXPECTED TO
REMAIN IN PLACE FOR AT LEAST THE NEXT 3-4 DAYS. ADDITIONAL
SHOWERS/TSTMS EXTEND FARTHER E OVER HISPANIOLA AND PUERTO RICO
IN ASSOCIATED WITH A TROPICAL WAVE...BUT MOST OF THE AREA S OF
15N/16N IS UNDER MAINLY FAIR SKIES AND DRIER LOW-LEVEL AIR. AN
UPPER TROUGH AND AREA OF LOW-LEVEL CONVERGENCE OVER THE CENTRAL
ATLC IS PRODUCING CONVECTION MAINLY E OF THE LESSER
ANTILLES...BUT BUT SOME OF THIS ACTIVITY HAS BEEN SPREADING W
ACROSS DOMINICA...MARTINIQUE...AND ST. LUCIA.

ATLANTIC...
A SHARP UPPER LEVEL RIDGE EXTENDS OVER THE W ATLC WATERS FROM
THE WINDWARD PASSAGE TO THE SOUTH CAROLINA COAST AND IS
SPREADING HIGH LEVEL CIRRUS ACROSS MOST OF THE AREA W OF 60W.
LONG BANDS OF SCATTERED MODERATE CONVECTION...INDIRECTLY
ASSOCIATED WITH T.D. TAMMY...STRETCH BENEATH THE RIDGE FROM THE
CAROLINA COAST TO THE SRN BAHAMAS...JUST E OF THE MAIN BAHAMA
ISLAND CHAIN. FARTHER E...A CUT-OFF UPPER LOW IS CENTERED NEAR
22N52W AND APPEARS TO HAVE BUILT DOWN TO THE SURFACE WITH A 1014
MB LOW FORMING NEAR 23N54W. THESE FEATURES ARE BOTH PRODUCED
SCATTERED MODERATE CONVECTION FROM 23N-28N BETWEEN 48W-56W. THE
UPPER TROUGH IS ALSO INTERACTING WITH A SURFACE TROUGH ALONG
22N51W 13N56W TO PRODUCE ADDITIONAL SCATTERED MODERATE
CONVECTION WITHIN 120 NM OF A LINE FROM 15N61W 14N56W 25N38W. A
70 KT WESTERLY UPPER LEVEL JET EXTENDS E OF THE CUT-OFF LOW
TOWARDS THE CANARY AND MADEIRA ISLANDS. A DISSIPATING FRONTAL
BOUNDARY HAS BECOME NEARLY STATIONARY BENEATH THE JET WITH ALL
UPPER LEVEL SUPPORT N OF THE AREA AND ONLY ISOLATED AREAS OF
SHOWERS ARE LOCATED NEAR THE BOUNDARY...ESPECIALLY E OF 30W. AN
UPPER LEVEL HIGH IS LOCATED IN THE TROPICS NEAR 12N34W AND IS
HELPING TO IMPROVE THE OUTFLOW OF THE TROPICAL WAVE ALONG 42W.

$$
BERG


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