[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 142345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI OCT 14 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

A 1005 MB LOW IS LOCATED OVER THE ISLAND OF JAMAICA NEAR
18N77W...ATTACHED TO A SURFACE TROUGH WHICH EXTENDS FROM
NICARAGUA TO THE WINDWARD PASSAGE. THE LOW AND TROUGH HAVE BEGUN
TO SEPARATE THEMSELVES FROM THE TROUGH LOCATED OVER THE W ATLC
WATERS AND DEEP CONVECTION HAS BEEN INCREASING NEAR THE LOW
CENTER THROUGHOUT THE DAY. VERY HEAVY RAINFALL IS CURRENTLY
LOCATED OVER JAMAICA EXTENDING EWD ALONG THE S COAST OF
HISPANIOLA...WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION
FROM 14N-19N BETWEEN 73W-79W. WIDELY SCATTERED MODERATE IS OVER
HISPANIOLA FROM 17N-20N BETWEEN 68W-73W. AN AMSU-B PASS AT 1931
UTC INDICATED THAT RAIN RATES JUST OFFSHORE FROM KINGSTON
JAMAICA WERE NEAR 0.8"/HOUR SO IT IS POSSIBLE THAT SEVERAL
INCHES OF RAIN HAVE ALREADY FALLEN OVER PARTS OF JAMAICA WITH A
THREAT FOR FLASH FLOODING. THE LOW HAS THE POSSIBILITY OF
DEVELOPING INTO A TROPICAL CYCLONE WITHIN THE NEXT 36 HRS
ESPECIALLY IF THE CENTER MOVES AND REMAINS OVER WATER...AND THE
DEEP CONVECTION IS ABLE TO PERSIST.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 34W S OF 21N MOVING W 15 KT.
THE WAVE HAS A BROAD LOW-LEVEL CIRCULATION WITH SEVERAL SWIRLS
NOTED IN SATELLITE IMAGERY. THE WAVE IS CONVECTIVELY ACTIVE BUT
IS UNDER THE INFLUENCE OF STRONG WESTERLY SHEAR DUE TO AN UPPER
LEVEL TROUGH ALONG 20N28W 15N40W...SO WIDELY SCATTERED MODERATE
CONVECTION IS DISPLACED E OF THE AXIS FROM 8N-18N BETWEEN
26W-33W.

CENTRAL ATLANTIC TROPICAL WAVE NEAR 45W HAS BEEN DROPPED FROM
THE ANALYSIS. THE WAVE HAS BEEN LOCATED ALONG THE LEADING EDGE
OF AN EASTERLY WIND SURGE...AND HAS BECOME INCREASINGLY LESS
DEFINED AS IT BECOMES INCORPORATED INTO THE CIRCULATION OF THE
TROPICAL WAVE TO THE E.

TROPICAL WAVE LOCATED JUST E OF BARBADOS ALONG 58W/59W S OF 20N
MOVING W 10-15 KT. AN UPPER LEVEL LOW NEAR 18N57W CONTINUES TO
PLACE WESTERLY SHEAR OVER THE WAVE BUT A WEAK CONVERGENCE LINE
IS NOTED MOVING TOWARDS THE LESSER ANTILLES. WIDELY SCATTERED
SHOWERS/TSTMS FROM 10N-15N BETWEEN 53W-60W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N10W 7N15W 15N32W...THEN ALONG
11N35W 10N47W...THEN FROM 11N80W WWD ACROSS SRN NICARAGUA.
SCATTERED MODERATE CONVECTION MOVING OFF THE COAST FROM 7N-11N
BETWEEN 10W-16W. SCATTERED SHOWERS/TSTMS FROM 5N-10N BETWEEN
33W-40W. ISOLATED SHOWERS/TSTMS FROM 6N-10N BETWEEN 43W-49W.
SCATTERED MODERATE/ISOLATED STRONG OVER NICARAGUA.

...DISCUSSION...

GULF OF MEXICO...
HIGH PRES CENTERED OVER W TEXAS HAS BUILT IN ACROSS ERN MEXICO
AND THE GULF OF MEXICO WITH NORTHERLY FLOW USHERING IN DRIER AIR
OFF THE N GULF COAST. THE N/NE WINDS COMING FROM TEXAS ARE
PRODUCING OROGRAPHIC LOW CLOUDS AND DRIZZLE OVER FAR NE MEXICO
EXTENDING FROM THE COAST NWWD THROUGH MONTERREY TO EL PASO
TEXAS. PATCHY CLOUDS AND ISOLATED SHOWERS ARE ALSO LOCATED OVER
THE GULF WATERS S OF 26N BUT DRIER AIR...DEWPOINTS IN THE UPPER
50S F...HAS CLEARED THE SKIES WITHIN 150 NM OF THE COAST. THE
MID/UPPER LEVELS ARE ALSO DRY DUE TO AN UPPER HIGH NEAR 24N87W
PRODUCING MODERATE TO STRONG SUBSIDENCE...STRONGEST NEAR CUBA
AND DECREASING TO THE NW. CONTINUED DRYING IS EXPECTED TO SPREAD
SWD OVER THE NEXT 48 HRS AND LAST AT LEAST THROUGH MID-WEEK WITH
THE DEEPEST MOISTURE AND GREATEST CHANCE FOR SHOWERS/TSTMS
LIMITED TO THE AREA FROM SE MEXICO TO W CUBA.

CARIBBEAN...
OF GREATEST CONCERN AT THE MOMENT IS THE 1005 MB LOW NEAR
JAMAICA WHICH IS PRODUCING LOCALLY HEAVY RAINS AND POSSIBLE
FLASH FLOODING...AND THE CHANCE FOR TROPICAL CYCLONE
DEVELOPMENT. SEE SPECIAL FEATURES FOR FURTHER DISCUSSION. THE
UPPER FLOW OVER THE CARIBBEAN IS DOMINATED BY E/NE WINDS AT
200-300 MB WITH AN UPPER RIDGE STRUNG THROUGH THE STRAITS OF
FLORIDA AND AN UPPER LOW APPROACHING THE NRN LEEWARD ISLANDS
FROM THE E. THE UPPER HIGH IS PRODUCING STRONG SUBSIDENCE OVER
THE NW CARIBBEAN FROM THE CAYMAN ISLANDS TO THE YUCATAN CHANNEL
WHILE MOISTURE REMAINS TRAPPED PRIMARILY OVER THE CENTRAL PART
OF THE BASIN. THE MOISTURE PLUME WHICH HAS BEEN AFFECTING THE
AREA OVER THE PAST FEW DAYS HAS SHRUNK A BIT AND NOW EXTENDS
FROM NICARAGUA/COSTA RICA TO HISPANIOLA WITH THE HEAVIEST
CONVECTION OCCURRING FROM JAMAICA TO HISPANIOLA. THE AREA E OF
68W IS RELATIVELY DRY WITH ONLY ISOLATED SHOWERS FROM MARTINIQUE
SWD TO NE VENEZUELA.

WEST ATLANTIC...
A WEAK COLD FRONT CONTINUES TO PUSH S OVER THE W ATLC WATERS
ALONG 32N63W 27N70W TO A 1010 MB LOW NEAR FT. PIERCE
FLORIDA...THEN CONTINUING ACROSS THE SE COAST OF FLORIDA TO THE
FLORIDA KEYS. THE FRONT IS BRINGING IN SLIGHTLY DRIER AIR WITH
PATCHY LOW CLOUDS N OF 27N...BUT IS EXPECTED TO DISSIPATE AS IT
SLOWLY PUSHES TO THE S. A SURFACE TROUGH IS LOCATED AHEAD OF THE
FRONT ALONG 31N59W 20N71W WITH A 1006 MB LOW NEAR 29N61W
SHOOTING TO THE NE. A SHARP UPPER TROUGH LOCATED ALONG 69W IS
PROVIDING A DIFFLUENT ENVIRONMENT FOR SCATTERED MODERATE
CONVECTION AHEAD OF THE LOW FROM 27N-32N BETWEEN 54W-60W.
SCATTERED MODERATE IS ALSO FROM 22N-26N BETWEEN 62W-67W.

EAST/CENTRAL ATLANTIC...
A LARGE UPPER LOW IS CENTERED ABOUT 250 NM E OF THE NRN LEEWARD
ISLANDS MOVING W 10-15 KT AND IS SPREADING DRIER AIR ACROSS THE
LESSER ANTILLES. MOIST AIR IS BEING PULLED UP THE E SIDE OF THE
LOW WITH ISOLATED SHOWERS/TSTMS DEVELOPING FROM BARBADOS 350 NM
TO THE E. FARTHER E...A LARGE UPPER TROUGH IS SURGING SWD PAST
THE AZORES TO 30N WITH AN 80-90 KT JET LOCATED ALONG 32N40W
30N27W. A COLD/STATIONARY FRONT HAS SAGGED INTO THE AREA ALONG
32N26W 28N37W 32N54W AND MOISTURE EXTENDING UP TO 500 NM S OF
THE JET AXIS IS FOSTERING ISOLATED SHOWERS/TSTMS WITHIN 200 NM
OF THE FRONT. A WEAK SURFACE TROUGH LIES S OF THE FRONT ALONG
25N36W 21N50W WITH A 1015 MB LOW NEAR 24N41W. AN UPPER TROUGH
LIES OVER THE TROPICS ALONG 20N30W 14N40W AND IS PRODUCING
WESTERLY SHEAR OVER THE TROPICAL WAVE ALONG 34W...WHILE ALSO
PROVIDING A FAVORABLE ENVIRONMENT FOR SCATTERED MODERATE
CONVECTION UP TO 450 NM W OF THE CAPE VERDE ISLANDS.

$$
BERG


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