[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111840
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU SEP 11 2014

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

AS OF 1500 UTC...TROPICAL DEPRESSION SIX HAS DEVELOPED IN THE
ATLANTIC WITH CENTER NEAR 16N37W MOVING NW AT 10 KT. A MOTION
TOWARD THE NW OR WNW IS EXPECTED DURING THE NEXT COUPLE OF DAYS.
MAXIMUM SUSTAINED WINDS ARE NEAR 30 KT...WITH HIGHER GUSTS.
STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS...AND THE
DEPRESSION COULD BECOME A TROPICAL STORM STORM LATER TODAY OR
TONIGHT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB.
SCATTERED TO NUMEROUS MODERATE CONVECTION IS WITHIN 150 NM OF
THE CENTER OF THE DEPRESSION FROM 16N-19N BETWEEN 36W-40W. OUTER
BANDS WITH ISOLATED MODERATE CONVECTION IS OCCURRING BETWEEN
150NM AND 300NM OF THE CENTER OF THE DEPRESSION. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 FOR
MORE DETAILS.

A 1015 MB SURFACE LOW IS LOCATED NEAR 27N78W DRIFTING WESTWARD.
A SURFACE TROUGH EXTENDS FROM 30N75W TO 24N78W THROUGH THE
CENTER OF THE SURFACE LOW. CONVECTION HAS BECOME A LITTLE MORE
CONCENTRATED AROUND THE LOW TODAY AND SLOW DEVELOPMENT IS
POSSIBLE BEFORE UPPER LEVEL WINDS BECOME LESS CONDUCIVE FOR
DEVELOPMENT LATER TONIGHT. SCATTERED MODERATE CONVECTION IS FROM
25N-28N BETWEEN 74W AND THE FL E COAST NEAR 80W. THIS LOW IS
EXPECTED TO CONTINUE SLOWLY WESTWARD ACROSS SOUTHERN FL OVER THE
NEXT 48 HOURS. THE CHANCE OF THIS FEATURE BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS IS MEDIUM.

...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING FROM THE ATLANTIC INTO THE E
CARIBBEAN. IT EXTENDS FROM 9N62W TO 21N61W MOVING W AT 15 KT.
SEVERAL SURFACE OBS...INCLUDING THOSE AT ST. LUCIA AND
GUADELOUPE THIS MORNING HAVE SHOWN A WIND SHIFT TO THE
SOUTHEAST...INDICATING PASSAGE OF THE TROPICAL WAVE. AN AREA OF
ENHANCED MOISTURE IS SEEN IN SSMI TPW FROM 10N-14N FROM 58W-65W.
ISOLATED MODERATE CONVECTION IS 12N-14N FROM 60W-65W.

A TROPICAL WAVE EXTENDS FROM SW GULF NEAR 24N93W...ACROSS MEXICO
AND INTO TO THE E PACIFIC NEAR 13N94W MOVING W AT 10-15 KT.
SCATTERED THUNDERSTORMS ARE FROM 18N-24N BETWEEN 90W-94W. THE
REMAINING CONVECTION IS LOCATED IN THE E PACIFIC AND IS
DISCUSSED IN THE TWDEP.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 14N17W TO 15N36W TO 08N45W. THE
ITCZ AXIS EXTENDS FROM 08N45W TO 06N57W. OTHER THAN CONVECTION
MENTIONED IN THE TROPICAL WAVES SECTION ABOVE...SCATTERED
MODERATE CONVECTION IS FROM 6N-14N BETWEEN 17W-33W.

...DISCUSSION...

GULF OF MEXICO...

SHOWERS AND THUNDERSTORMS IN THE SW GULF IS ASSOCIATED WITH A
TROPICAL WAVE DISCUSSED IN THE TROPICAL WAVES SECTION. AN UPPER
LEVEL LOW IS OVER THE W GULF AND UPPER LEVEL HIGH PRESSURE IS
LOCATED OVER THE SE CONUS AND EXTENDS IN THE NE GULF. WEAK UPPER
LEVEL DIFFLUENCE BETWEEN THESE TWO FEATURES IS SUPPORTING
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE E GULF. OVER
THE NEXT 24 HOURS THE UPPER LEVEL ANTICYCLONE WILL BECOME
CENTERED ACROSS THE NORTHERN GULF COAST WITH A LARGE AREA OF MID
TO UPPER LEVEL DRY AIR EXPECTED TO LIMIT CONVECTION ACROSS THE
NORTHERN HALF OF THE GULF ON FRIDAY. UPPER LEVEL DIFFLUENCE TO
THE SOUTH OF THE UPPER LEVEL ANTICYCLONE COMBINED WITH DEEP LAYER
MOISTURE WILL HELP SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS THE S GULF THROUGH FRIDAY. A SURFACE LOW OVER THE BAHAMAS
WILL SHIFT E ACROSS FLORIDA FRIDAY AND MAY BRING ADDITIONAL
SHOWERS AND THUNDERSTORMS TO THE SE GULF OVER THE WEEKEND.

CARIBBEAN SEA...

UPPER LEVEL WESTERLIES COVER MUCH OF THE CARIBBEAN ON THE SOUTH
SIDE OF A BROAD AREA OF UPPER LEVEL LOW PRESSURE CENTERED NEAR
22N64W. OTHER THAN CONVECTION NOTED IN THE TROPICAL WAVES
SECTION...A WEAK AREA OF UPPER LEVEL DIFFLUENCE OVER THE YUCATAN
COMBINED WITH DEEP MOISTURE IS SUPPORTING SCATTERED MODERATE
CONVECTION FROM THE E YUCATAN INTO THE NORTHWESTERN CARIBBEAN
FROM 18N-24N BETWEEN 85W-89W. OVER THE NEXT 24 HOURS THE AREA OF
DIFFLUENCE OVER THE YUCATAN AND NORTHWEST CARIBBEAN WILL WEAKEN
AND SHIFT WESTWARD. THIS SHOULD CAUSE ANY CONVECTION ACROSS THE
NORTHWESTERN CARIBBEAN TO LESSEN IN COVERAGE AND INTENSITY
THROUGH FRIDAY. THE WESTWARD MOVING TROPICAL WAVE THAT IS
ENTERING THE E CARIBBEAN MAY BRING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS MAINLY ACROSS THE LESSER ANTILLES S OF 15
N THROUGH FRIDAY.

...HISPANIOLA...
CYCLONIC UPPER LEVEL FLOW DOMINATES THE AREA FROM AN UPPER LOW
CENTERED NORTHEAST OF THE AREA NEAR 22N64W. THIS UPPER LOW IS
SUPPORTING MAINLY DIURNAL ISOLATED THUNDERSTORMS ACROSS
HISPANIOLA TODAY. A TROPICAL WAVE APPROACHING FROM THE EAST AND
ONGOING INFLUENCE FROM THE UPPER LOW WILL SUPPORT SCATTERED
THUNDERSTORMS ACROSS THE AREA THROUGH FRIDAY.


ATLANTIC OCEAN...
A LARGE UPPER LOW IS CENTERED NEAR 26N64W DRIFTING
SOUTHWESTWARD. A NEARLY STATIONARY SURFACE TROUGH TO THE NORTH
OF THIS UPPER LOW FROM 26N63W TO 30N61W IS SUPPORTING SCATTERED
MODERATE CONVECTION FROM 25N-31N BETWEEN 60W-65W.  FOR
INFORMATION REGARDING TROPICAL DEPRESSION SIX IN THE CENTRAL
ATLANTIC AND THE SURFACE LOW OVER THE BAHAMAS...PLEASE SEE THE
SPECIAL FEATURES SECTION OF THE DISCUSSION.

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

$$
LATTO


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