[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 290602
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE SEP 29 2015

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION ELEVEN INTENSIFIED INTO TROPICAL STORM
JOAQUIN. AT 0300 UTC ITS CENTER IS LOCATED NEAR 26.7N 70.4W OR
ABOUT 348 NM NE OF THE CENTRAL BAHAMAS. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 35
KT WITH GUSTS TO 45 KT. NUMEROUS MODERATE/ISOLATED STRONG
CONVECTION IS FROM 22N-26N BETWEEN 68W-71W...SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS ARE FROM 20N-27N BETWEEN 66W-73W.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

SOUTHERLY INFLOW ASSOCIATED WITH A 1009 MB LOW CENTERED NEAR
26N83W IS GENERATING A SWATH OF NEAR GALE TO GALE FORCE WINDS
ACROSS THE E-SE GULF OF MEXICO. THE STRONG WIND FIELD GENERALLY
COINCIDES WITH A REGION OF DIFFLUENCE ALOFT AND SCATTERED
MODERATE CONVECTION E OF 85W. GALE FORCE WINDS AND ASSOCIATED
SEAS WILL DIMINISH BY 0600 UTC TODAY.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLC E OF THE CAPE VERDE ISLANDS
WITH TILTED AXIS EXTENDING FROM 16N17W SW TO A 1010 MB LOW
EMBEDDED IN THE MONSOON TROUGH NEAR 10N21W. SSMI TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED MAINLY IN A
MODERATE MOIST ENVIRONMENT THAT ALONG WITH MIDDLE LEVEL
DIFFLUENCE AHEAD OF THE SURFACE LOW SUPPORT SCATTERED TO
ISOLATED MODERATE CONVECTION AND TSTMS FROM 13N TO 16N BETWEEN
17W AND 22W AND FROM 07N TO 12N BETWEEN 22W AND 26W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
A 1010 MB LOW NEAR 10N21W TO 11N30W TO 09N41W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 09N41W TO 05N53W. ASIDE FROM
THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE...SCATTERED
MODERATE CONVECTION IS FROM 05N-11W BETWEEN 28W-42W.

...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE CONTINUES TO DOMINATE ACROSS THE
GULF...EXCEPT FOR THE W-SW BASIN WHERE A WEAK HIGH PRESSURE
CENTER IS ANALYZED. ALOFT...A MIDDLE TO UPPER LEVEL LOW AND
ASSOCIATED TROUGH EXTEND FROM ARKANSAS SW TO CENTRAL MEXICO AND
INFLUENCE A 1007 MB LOW PRESSURE CENTER LOCATED IN THE NW GULF
NEAR 28N94W. WITH NO SUPPORT ALOFT...A FORMER STATIONARY FRONT
STARTS TO DISSIPATE ALONG NORTHERN FLORIDA SW TO A 1007 MB LOW
OVER THE NE BASIN NEAR 29N86W. SOUTHEAST OF THIS LOW CENTER...A
1009 MB LOW CENTER AND ASSOCIATED TROUGH SUPPORT NEAR GALE TO
GALE FORCE WINDS. SEE THE SPECIAL FEATURES SECTION FOR DETAILS.
ASIDE THE CONVECTION OVER THE E GULF DISCUSSED IN THE SPECIAL
FEATURES...MOISTURE INFLOW FROM THE EPAC ASSOCIATED WITH
TROPICAL STORM MARTY ENHANCES SCATTERED TO ISOLATED SHOWERS OVER
THE SW BASIN. EXCEPT FOR THE E GULF E OF 85W...WINDS ARE 15 KT
OR LESS AND VARIABLE. THE UPPER LEVEL LOW AND ASSOCIATED NEARLY
COLLOCATED SURFACE LOW IS EXPECTED TO BE SLOW TO MOVE THE NEXT
FEW DAYS WHILE THE EASTERN GULF LOW ACCELERATES NORTHWARD TO THE
FLORIDA BIG BEND REGION WITHIN THE NEXT 24 HOURS. ASIDE FROM
POTENTIAL TROPICAL CYCLONE DEVELOPMENT...THE MAIN IMPACT WILL
CONTINUE TO BE CONVECTIVE PRECIPITATION...HEAVY AT TIMES...AND
POTENTIAL FLOODING ACROSS FLORIDA.

CARIBBEAN SEA...

A SURFACE TROUGH CURRENTLY EXTENDING FROM THE NORTHERN YUCATAN
PENINSULA TO GUATEMALA ALONG WITH ABUNDANT MOISTURE OVER THE FAR
NW CARIBBEAN SUPPORT SCATTERED SHOWERS AND TSTMS W OF 84W.
MODERATE SHALLOW MOISTURE OVER THE SW BASIN AND THE MONSOON
TROUGH EXTENDING FROM COSTA RICA TO NORTHERN COLOMBIA SUPPORT
ISOLATED SHOWERS AND TSTMS S OF 10N. SIMILAR CONVECTION IS
OBSERVED OVER HISPANIOLA BEING INFLUENCED BY TROPICAL STORM
JOAQUIN LOCATED IN THE SW N ATLC. SEE SPECIAL FEATURES FOR MORE
INFORMATION. WATER VAPOR IMAGERY INDICATE RELATIVELY STRONG DRY
AIR ALOFT IN ASSOCIATION WITH A BROAD AND ELONGATED UPPER LEVEL
LOW CENTERED NEAR 17N62W. OTHERWISE...MAINLY FRESH TO OCCASIONAL
STRONG TRADES PERSIST WITH THE STRONGEST WINDS NOTED ACROSS
SOUTH-CENTRAL PORTIONS.

...HISPANIOLA...

MOISTURE ASSOCIATED WITH THE RECENTLY UPGRADED TROPICAL STORM
JOAQUIN IN THE SW N ATLC IS BEING ADVECTED BY CYCLONIC FLOW
ACROSS THE ISLAND...THUS SUPPORTING ISOLATED SHOWERS AND TSTMS.
PRECIPITATION ACTIVITY IS EXPECTED TO CEASE LATE TUESDAY AS THE
STORM MOVES W-NW OVER ATLC WATERS.

ATLANTIC OCEAN...

THE MAIN FEATURE OVER THE ATLC IS RECENTLY UPGRADED TROPICAL
STORM JOAQUIN DISCUSSED IN SPECIAL FEATURES. THE REMAINDER OF
THE SW NORTH ATLC IS UNDER THE INFLUENCE OF MOSTLY NORTH-
NORTHEASTERLY FLOW ALOFT ON THE EASTERN PERIPHERY OF AN UPPER
LEVEL RIDGE ANCHORED OVER THE OFFSHORE WATERS OF THE FLORIDA
PENINSULA NEAR 29N77W. TO THE ESE OF JOAQUIN...A LARGE AREA OF
DISTURBED WEATHER IS IN THE CENTRAL ATLC ASSOCIATED WITH A
FRONTAL TROUGH AND THE REMNANTS OF IDA. THE CENTER OF THIS
DISTURBANCE IS A 1008 MB LOW NEAR 23N53W FROM WHICH A TROUGH
EXTENDS SW TO 18N55W. SCATTERED MODERATE CONVECTION AND TSTMS
ARE FROM 19N TO 24N BETWEEN 48W AND 55W. SIMILAR CONVECTION IS
FROM 24N TO 28N BETWEEN 55W AND 60W. AN UPPER TROUGH CONTINUES
TO SUPPORT A STATIONARY FRONT ALONG 29N33W TO 27N50W TO 27N60W
WHERE IT STARTS TO DISSIPATE.

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

$$
NR
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