[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU OCT 04 2012

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN 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
VALID THROUGH 2315 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM OSCAR AT 04/2100 UTC IS NEAR 21.3N
41.0W ABOUT 1015 NM WNW OF THE CAPE VERDE ISLANDS MOVING NE AT
11 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. THE
MAXIMUM SUSTAINED WIND SPEEDS ARE 40 KNOTS WITH GUSTS TO 50
KNOTS. PUBLIC ADVISORIES ON TROPICAL STORM OSCAR ARE ISSUED
UNDER WMO HEADER WTNT35 KNHC AND UNDER AWIPS HEADER MIATCPAT5.
FORECAST/ADVISORIES ARE ISSUED UNDER WMO HEADER WTNT25 KNHC AND
UNDER AWIPS HEADER MIATCMAT5. OSCAR IS EXPERIENCING STRONG
WESTERLY SHEAR...WHICH IS MAINTAINING DEEP CONVECTION WELL E OF
THE CENTER. NUMEROUS STRONG CONVECTION IS FROM 19N-22N BETWEEN
35W-39W.  SCATTERED MODERATE CONVECTION 17N-23N BETWEEN 34W-40W
OUTSIDE OF THE NUMEROUS STRONG CONVECTION.

...TROPICAL WAVES...

AN EASTERN CARIBBEAN TROPICAL WAVE EXTENDS FROM 18N65W TO 10N67W
MOVING WNW AT 15 KT. AN ENHANCED AREA OF MOISTURE IS NOTED ON
SSMI TOTAL PRECIPITABLE WATER IMAGERY ON THE EASTERN SIDE OF THE
WAVE AXIS. LITTLE TO NO DEEP CONVECTION IS PRESENT WITH THIS
WAVE...HOWEVER...SCATTERED SHOWERS ARE WITHIN 120 NM OF THE WAVE
AXIS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL AT 14N17W
TO 12N22W. THE ITCZ CONTINUES FROM 12N22W TO 6N38W TO 12N55W TO
THE COAST OF VENEZUELA AT 10N63W. SCATTERED MODERATE CONVECTION
IS OFF THE COAST OF WEST AFRICA SOUTH OF THE MONSOON TROUGH AND
ITCZ FROM 5N-10N BETWEEN 20W-30W. SCATTERED MODERATE CONVECTION
IS WITHIN 180 NM OF THE ITCZ BETWEEN 32W-42W.  SCATTERED
MODERATE CONVECTION IS WITHIN 120 NM N OF THE ITCZ BETWEEN
53W-57W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 2100 UTC...A SMALL 1013 MB LOW HAD DEVELOPED NEAR 19N93W
AT THE SOUTHERN END OF A SURFACE TROUGH.  THE LOW WAS IDENTIFIED
BY A COMBINATION OF AN ASCAT PASS AT 1622 UTC...SURFACE
OBSERVATIONS FROM MEXICO...AND VISIBLE SATELLITE IMAGERY.  THE
TROUGH EXTENDS FROM THE LOW NORTH-NORTHEASTWARD TO THE BIG BEND
AREA OF FLORIDA NEAR 30N84W.  THE TROUGH IS HELPING TO INDUCE
THE DEEP CONVECTION SEEN OVER THE WESTERN CARIBBEAN...CENTRAL
AMERICA...CUBA...AND THE FLORIDA PENINSULA.  A SHARP UPPER LEVEL
TROUGH IN THE WESTERN GULF OF MEXICO IS ALSO PROVIDING SOME
DYNAMICAL SUPPORT FOR THE SURFACE TROUGH AND THE DEEP
CONVECTION.  ON FRIDAY...TROUGHING MAY BECOME RESTRICTED TO THE
SOUTHERN HALF OF THE GULF AND MOVE WESTWARD.  EXPECT SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION IN THE SOUTHWESTERN GULF
OF MEXICO AND NORTHERN CENTRAL AMERICA IN THE NEXT DAY OR SO.
SURFACE WINDS ARE GENERALLY WEAK THROUGHOUT MOST OF THE
GULF...LESS THAN 20 KT.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS IN THE E CARIBBEAN AS NOTED ABOVE.  SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS OCCURRING IN THE W
CARIBBEAN N OF 12N W OF 82.  THIS IS IN ASSOCIATION WITH THE
AFOREMENTIONED TROUGH OVER THE GULF OF MEXICO AND AN UPPER LOW
IN THE CARIBBEAN NEAR 19N80W.  SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS ALSO SEEN WITHIN 180 NM OF THE PANAMA AND
COSTA RICA COASTS.  THIS CONVECTION IS RELATED TO THE MONSOON
TROUGH EXTENDING E FROM THE NORTHEASTERN PACIFIC.  THE
CONVECTION WILL GRADUALLY SHIFT WESTWARD AND CONTINUE TO IMPACT
WESTERNMOST CARIBBEAN AND CENTRAL AMERICA ON FRIDAY.  SURFACE
E-NE TRADEWINDS REMAIN LIGHT...PRIMARILY BELOW 20 KT.

THE ATLANTIC OCEAN...
A 1023 MB HIGH IS OVER THE W ATLANTIC AT 32N74W WHICH IS
INDUCING RELATIVELY FAIR WEATHER AND WINDS LESS THAN 20 KT W OF
60W.  A SECOND HIGH OF 1016 MB IS IN THE E ATLANTIC NEAR 26N21W
AND WINDS ARE LESS THAN 20 KT E OF TROPICAL STORM OSCAR.  AN
UPPER LOW CENTERED NEAR 22N58W IS KICKING OFF SCATTERED SHOWERS
WITHIN 180 NM OF THE CENTER.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
LANDSEA







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