[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 082348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE OCT 08 2013

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 THROUGH
2315 UTC.

...SPECIAL FEATURES...
TROPICAL WAVE EXTENDS FROM 10N26W TO 17N25W MOVING W-NW AT 10-15
KT. A 1010 MB LOW IS CENTERED AT THE SOUTHERN EXTENT OF THE WAVE
AXIS AND REMAINS EMBEDDED WITHIN A BROAD MONSOONAL GYRE FROM 08N-
15N BETWEEN 20W-32W. THE ENTIRE SYSTEM IS LOCATED BENEATH THE
WESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED OVER THE EASTERN TROPICAL ATLC NEAR 16N24W THAT IS
PROVIDING AN OVERALL FAVORABLE UPPER LEVEL DIFFLUENT
ENVIRONMENT. SCATTERED MODERATE CONVECTION IS FROM 10N-14N
BETWEEN 26W-30W...WITH ISOLATED MODERATE CONVECTION ELSEWHERE
FROM 06N-14N BETWEEN 20W-30W.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 13N41W TO 21N42W MOVING W AT 10-15
KT. TO THE WEST OF THE WAVE AXIS AN UPPER LEVEL LOW IS CENTERED
NEAR 21N44W THAT IS PROVIDING INCREASED SOUTHWESTERLY UPPER
LEVEL SHEAR TO THE WAVE. EXAMINING TOTAL PRECIPITABLE WATER
IMAGERY...THE MOISTURE FIELD ASSOCIATED WITH THE WAVE CONTINUES
TO STRETCH POLEWARD WITH ENERGY LIKELY FRACTURING NORTHWARD.
WITH THE SHEAR IN PLACE...ISOLATED MODERATE CONVECTION IS
OCCURRING WELL TO THE EAST OF THE WAVE AXIS FROM 12N-24N BETWEEN
33W-39W.

TROPICAL WAVE EXTENDS FROM 11N71W TO 18N69W MOVING W AT 10 KT.
PLENTY OF MOISTURE IS NOTED ON WATER VAPOR IMAGERY ACROSS THE
EASTERN CARIBBEAN SEA AS THE WAVE REMAINS BENEATH MOIST
SOUTHWESTERLY FLOW EAST OF AN UPPER LEVEL TROUGH AXIS EXTENDING
FROM 22N69W SW TO 13N77W. LOW-LEVEL MOISTURE CONVERGENCE IS
MAXIMIZED EAST OF THE TROPICAL WAVE WITH SCATTERED MODERATE
CONVECTION FROM 12N-22N BETWEEN 59W-71W. THIS CONVECTION IS
LIKELY ENHANCED DUE TO THE UPPER LEVEL DIFFLUENCE GENERATED FROM
THE UPPER LEVEL TROUGHING.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
13N17W TO 10N26W TO 11N32W. THE INTERTROPICAL CONVERGENCE ZONE
AXIS EXTENDS FROM 11N32W TO 12N42W TO 11N52W. BESIDES THE
CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...WIDELY SCATTERED
MODERATE CONVECTION IS FROM 04N-12N BETWEEN 10W-20W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM OVER THE CAROLINAS
NEAR 34N79W SW TO A BASE OVER THE WESTERN GULF NEAR 23N93W THAT
SUPPORTS A 1009 MB LOW CENTERED OFFSHORE OF JACKSONVILLE FLORIDA
NEAR 30N81W. A COLD FRONT EXTENDS SW FROM THE LOW CENTER ACROSS
THE SOUTHERN FLORIDA PENINSULA TO 26N82W TO THE YUCATAN
PENINSULA COAST NEAR 21N89W THEN TO 18N94W IN THE SW GULF
WATERS. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE
OCCURRING WITHIN 120 NM EITHER SIDE OF THE COLD FRONT AND AN
AREA S OF 21N W OF 94W. A SECONDARY SURFACE TROUGH IS ANALYZED
FROM THE LOW CENTER ACROSS THE NORTHERN FLORIDA PENINSULA TO
28N85W DENOTING A MORE SIGNIFICANT DEWPOINT DEPRESSION AND THUS
A DRIER AIRMASS MOVING IN BEHIND THE FRONT. OTHERWISE...THE
REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED OVER THE MIDDLE AND LOWER MISSISSIPPI RIVER VALLEY TO
THE NORTH AND A 1021 MB HIGH CENTERED OVER EASTERN MEXICO NEAR
22N99W. CLEAR SKIES AND FAIR CONDITIONS PREVAIL ON LIGHT
NORTHERLY WINDS IN THE RANGE OF 10 TO 15 KT GENERALLY NW OF A
LINE FROM 30N85W TO 21N97W.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH AXIS SPLITS THE CARIBBEAN BASIN IN HALF
WITH THE TROUGH AXIS EXTENDING FROM OVER THE SW NORTH ATLC NEAR
24N69W SW TO A BASE OVER THE SW CARIBBEAN NEAR 12N78W. TO THE
WEST OF THE AXIS...WATER VAPOR IMAGERY INDICATES DRY AND STABLE
NORTH-NORTHEASTERLY WINDS ALOFT. WITH THE APPROACH OF A COLD
FRONT MOVING SE ACROSS THE SE GULF OF MEXICO...THE ATMOSPHERE
MOISTENS CLOSER TO THE YUCATAN PENINSULA AND AREAS IN THE
VICINITY OF THE YUCATAN CHANNEL WITH WIDELY SCATTERED SHOWERS
AND ISOLATED TSTMS OCCURRING WEST OF A LINE FROM 22N85W TO
10N78W. THIS AREA INCLUDES THE GULF OF HONDURAS...AND INLAND
PORTIONS OF CENTRAL AMERICA THIS EVENING. LIKELY AIDING THE
CONVECTION IN THE SW CARIBBEAN IS THE CLOSE PROXIMITY OF THE
MONSOON TROUGH AXIS ANALYZED ALONG 09N/10N BETWEEN NORTHERN
COLOMBIA AND COSTA RICA. TO THE EAST OF THE UPPER LEVEL TROUGH
AXIS...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER
THE EASTERN CARIBBEAN NEAR 13N66W. THE OVERALL DIFFLUENT
ENVIRONMENT EAST OF THE TROUGH AXIS ALONG WITH LOW-LEVEL
MOISTURE CONVERGENCE AIDED BY THE PRESENCE OF A TROPICAL WAVE
ALONG 70W IS GENERATING SCATTERED SHOWERS AND WIDELY SCATTERED
TSTMS FROM 12N-23N BETWEEN 59W-71W.

HISPANIOLA...
CURRENTLY SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS
PORTIONS OF THE DOMINICAN REPUBLIC AND THIS CONVECTION IS LIKELY
ENHANCED DUE TO A TROPICAL WAVE PASSING TO THE SOUTH ALONG 70W
AND AN UPPER LEVEL TROUGH AXIS THAT EXTENDS FROM OVER THE SW
NORTH ATLC TO OVER THE WESTERN PORTION OF THE ISLAND THIS
EVENING. ATMOSPHERIC MOISTURE AND CONVECTION INCREASE TO THE
EAST AND AS THE UPPER LEVEL TROUGH IS FORECAST TO REMAIN FAIRLY
STATIONARY OVER THE NEXT 24 HOURS...ISOLATED SHOWERS AND TSTMS
ARE EXPECTED TO PERSIST THROUGH THE OVERNIGHT HOURS WITH AN
INCREASE IN AREAL COVERAGE WEDNESDAY AFTERNOON AND EVENING AS
PEAK HEATING AND INSTABILITY MAX OUT DURING THOSE HOURS.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE CAROLINAS NEAR
34N79W THAT SUPPORTS A 1009 MB LOW CENTERED OFFSHORE OF
JACKSONVILLE FLORIDA NEAR 30N80W. A STATIONARY FRONT EXTENDS NE
FROM THE LOW TO BEYOND 32N78W AND A COLD FRONT EXTENDS SOUTH-
SOUTHWEST FROM THE LOW TO 26N82W AND INTO THE SE GULF OF MEXICO.
ISOLATED SHOWERS AND TSTMS ARE OCCURRING N OF 25N W OF 72W
ACROSS MOST OF THE SW NORTH ATLC. FARTHER EAST...AN UPPER LEVEL
LOW IS NOTED ON WATER VAPOR IMAGERY CENTERED NEAR 25N68W THAT
SUPPORTS A WEAK 1013 MB LOW CENTERED NEAR 30N68W AND A SURFACE
TROUGH EXTENDING E-SE FROM THE LOW TO 26N62W. WHILE NO NOTABLE
SURFACE FEATURE IS ASSOCIATED WITH THE UPPER LEVEL LOW...PLENTY
OF MIDDLE TO UPPER LEVEL DIFFLUENCE BETWEEN 55W-68W IS
GENERATING A LARGE AREA OF SCATTERED SHOWERS AND TSTMS FROM 18N-
31N BETWEEN 59W-66W. FINALLY...A DEEP LAYERED UPPER LEVEL LOW IS
NOTED ON WATER VAPOR IMAGERY CENTERED NEAR 43N39W THAT SUPPORTS
A COLD FRONT THAT SKIRTS THE CENTRAL ATLC DISCUSSION WATERS FROM
32N34W TO29N40W TO 28N47W. ISOLATED SHOWERS ARE OCCURRING WITHIN
120 NM EITHER SIDE OF THE BOUNDARY.

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

$$
HUFFMAN


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