[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 092353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI OCT 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS AT ABOUT 170 NM W OF THE CAPE VERDE ISLANDS
WITH AXIS EXTENDING FROM 20N26W TO 10N28W...MOVING W AT 10-15
KT. VISIBLE SATELLITE IMAGERY DEPICTS AN INVERTED-V PATTERN IN
THE CLOUD FIELD AND LATEST GFS 700 MB STREAMLINES ALSO SHOW AN
INVERTED TROUGH NEAR 24W-30W. TPW IMAGERY SHOWS THAT THE WAVE IS
EMBEDDED IN A SURGE OF MOISTURE SUPPORTING SCATTERED MODERATE
CONVECTION W OF THE WAVE AXIS FROM 11N-16N AND W OF 29W WHERE IT
COMBINES WITH THE ITCZ CONVECTION.

A LOW AMPLITUDE TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH
AXIS EXTENDING FROM 16N46W TO 10N46W. AFRICAN DUST SURROUNDS THE
WAVE AS NOTED ON THE SAHARAN AIR LAYER FROM UW-CIMSS. ISOLATED
MODERATE CONVECTION IS NEAR THE SOUTHERN END OF THE WAVE AXIS
S OF 12N BETWEEN 42W-47W.

A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS
EXTENDING FROM 19N69W TO 12N69W...MOVING OVER DOMINICAN REPUBLIC
AT ABOUT 10-15 KT. THE TPW IMAGERY INDICATES A BULGE OF MOISTURE
IN ASSOCIATION WITH THIS WAVE. THIS SYSTEM IS WELL DEPICTED IN
THE LATEST GFS 700 MB STREAMLINES AND 850 MB VORTICITY ANALYSIS.
THE WAVE COMBINED WITH AN UPPER-LEVEL LOW CENTERED S OF
HISPANIOLA ARE ENHANCING SCATTERED MODERATE CONVECTION BETWEEN
65W-73W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
11N15W TO NEAR 13N23W. THE ITCZ AXIS BEGINS W OF A TROPICAL WAVE
NEAR 11N32W TO 09N46W TO 09N61W.  ASIDE OF THE CONVECTION
RELATED TO THE TROPICAL WAVES DISCUSSED IN THE SECTION ABOVE...
SCATTERED MODERATE CONVECTION IS FROM 08N-12N BETWEEN 32W-58W.

...DISCUSSION...

GULF OF MEXICO...

A SURFACE TROUGH PERSISTS OVER THE EASTERN GULF AND STRETCHES
FROM 29N84W TO 23N90W. ISOLATED CONVECTION IS OBSERVED ALONG THE
NORTHERN PORTION OF THIS BOUNDARY. A SURFACE RIDGE PREVAILS
ACROSS THE WESTERN CONUS AND EXTENDS ACROSS MEXICO REACHING THE
GULF. ISOLATED CONVECTION IS MOVING FROM THE NE COAST OF MEXICO
OVER THE GULF WATERS MAINLY N OF 24N AND W OF 96W.  LOOKING
AHEAD...A WEAK COLD FRONT IS FORECAST TO REACH THE NORTHERN GULF
BY SATURDAY EXTENDING ACROSS THE SE AND SOUTH-CENTRAL GULF BY
SUNDAY WHERE IT WILL GRADUALLY DISSIPATE. WEAK HIGH PRESSURE
WILL FOLLOW THE FRONT. ALOFT...AN ANTICYCLONE CENTERED OVER THE
SW GULF EXTENDS A RIDGE ACROSS THE ENTIRE REGION AND THE STATE
OF FLORIDA.

CARIBBEAN SEA...

THE TROPICAL WAVE CURRENTLY LOCATED OVER EASTERN HISPANIOLA
ALONG 69W AND WILL MOVE ACROSS THE CENTRAL CARIBBEAN TONIGHT
THROUGH LATE SATURDAY NIGHT AND ACROSS THE WESTERN CARIBBEAN ON
SUNDAY. FOR MORE INFORMATION...PLEASE REFER TO THE SECTION
ABOVE. LATEST SCATTEROMETER PASSES DEPICT FRESH TRADE WINDS
ACROSS THE SOUTH-CENTRAL CARIBBEAN S OF 15N BETWEEN 67W-72W
WHILE GENTLE TO MODERATE TRADES PREVAIL ELSEWHERE. THIS PATTERN
IS FORECAST TO PERSIST OVER THE NEXT SEVERAL DAYS WITH FRESH TO
LOCALLY STRONG TRADE WINDS NEAR THE COAST OF WESTERN VENEZUELA
AND NORTHERN COLOMBIA AT NIGHT. THE TRADES WILL CARRY ISOLATED
TO SCATTERED SHOWERS ACROSS THE BASIN. A SIMILAR WEATHER PATTERN
IS EXPECTED OVER THE NEXT 24 HOURS.

...HISPANIOLA...

THE UPPER-LEVEL LOW LOCATED S OF THE ISLAND COMBINED WITH THE
PASSAGE OF A TROPICAL WAVE AND THE LOCAL EFFECTS AS DAYTIME
HEATING...LOCAL SEA BREEZES AND MOUNTAIN SLOPES...TO INCREASE
THE CONVECTION ACTIVITY ACROSS THE AREA. LOCALLY HEAVY RAINFALL
COULD BE POSSIBLE AND GUSTY WINDS DUE TO THE PRESENCE OF THE
TSTMS. BY SUNDAY...THE UPPER-LEVEL LOW IS EXPECTED TO DISSIPATE
AND A STRONG UPPER-LEVEL TROUGH IS FORECAST TO APPROACH FROM THE
W.

ATLANTIC OCEAN...

A WEAK 1015 MB SURFACE LOW IS ALONG THE E COAST OF FLORIDA NEAR
28N80W. VISIBLE SATELLITE IMAGERY AND DOPPLER RADAR FROM
MELBOURNE SHOWED THE CYCLONIC CIRCULATION ASSOCIATED WITH THIS
LOW. THIS SYSTEM IS LIKELY ASSOCIATED WITH AN OLD FRONTAL
BOUNDARY THAT WAS ANALYZED AS A WEAK STATIONARY FRONT FROM
28N80W TO 31N67W THEN AS A COLD FRONT FROM THAT POINT TO A 1012
MB LOW CENTERED NEAR 33N64W. TO THE E...A SURFACE
TROUGH...LIKELY PART OF THE ENERGY ASSOCIATED WITH THE TROPICAL
WAVE LOCATED OVER THE E CARIBBEAN...RUNS FROM 26N65W TO 20N67W.
SCATTERED MODERATE CONVECTION IS NOTED ON THE E SIDE OF THE
TROUGH SUPPORTED BY UPPER-LEVEL DIFFLUENCE. A 1020 MB SURFACE
HIGH IS LOCATED NEAR 28N49W. A WEAKENING COLD FRONT WAS ANALYZED
FROM 23N43W TO 31N19W WITH ISOLATED CONVECTION. EXPECT FOR THE
FRONTS TO WEAKEN WITHIN THE NEXT 24 HOURS.

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

$$

ERA
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