[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 13 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.

...SPECIAL FEATURE...

AN AREA OF DISTURBED WEATHER IS ASSOCIATED WITH A BROAD LOW
PRESSURE SYSTEM LOCATED NEAR 11N36W WITH AN EMBEDDED TROPICAL
WAVE EXTENDING FROM THE LOW CENTER TO 16N34W. THIS AREA IS
SHOWING SIGNS OF ORGANIZATION AT THIS TIME...AND A TROPICAL
DEPRESSION COULD DEVELOP OVER THE NEXT 24 TO 48 HOURS WHILE THE
SYSTEM MOVES WNW ACROSS THE TROPICAL ATLANTIC. SCATTERED
MODERATE CONVECTION IS FROM 07N-13N BETWEEN 32W-40W. THIS SYSTEM
HAS A HIGH CHANCE OF DEVELOPMENT OVER THE NEXT 48 HOURS.

...TROPICAL WAVES...

A TROPICAL WAVE IS ACROSS THE CENTRAL ATLANTIC WITH AXIS
EXTENDING FROM 16N34W TO A 1010 MB LOW CENTERED NEAR
11N35W...MOVING W AT ABOUT 15-20 KT. THESE FEATURES ARE
DISCUSSED IN THE SPECIAL FEATURES SECTION...PLEASE REFER TO THIS
SECTION ABOVE FOR MORE DETAILS.

A TROPICAL WAVE IS MOVING ACROSS THE W-CENTRAL ATLANTIC WITH
AXIS EXTENDING FROM 19N54W TO 11N55W...MOVING W AT 15 KT. THE
WAVE COINCIDES WITH A BROAD 700 MB TROUGHING BETWEEN 50W-60W AND
TPW IMAGERY DEPICTS AN AREA OF HIGH MOISTURE E OF THE WAVE AXIS
MAINLY E OF 55W. ISOLATED MODERATE CONVECTION IS OBSERVED IN THE
ENVIRONMENT OF THIS WAVE S OF 14N.

A TROPICAL WAVE IS MOVING ACROSS THE W-CENTRAL CARIBBEAN WITH
AXIS EXTENDING FROM 18N75W TO 11N74W...MOVING W AT 15-20 KT. THE
WAVE COINCIDES WITH A BROAD 700 MB TROUGHING BETWEEN 70W-80W AND
TPW IMAGERY DEPICTS AN AREA OF MODERATE MOISTURE IN THE
ENVIRONMENT OF THE WAVE. THE NORTHERN PORTION OF THE WAVE IS
INTERACTING WITH AN UPPER-LEVEL LOW CENTERED JUST N OF
HISPANIOLA GENERATING ISOLATED MODERATE CONVECTION MAINLY N OF
17N.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS THE COAST OF AFRICA INTO THE
TROPICAL ATLANTIC NEAR 11N15W TO 09N18W TO A 1010 MB LOW NEAR
11N36W TO ANOTHER 1010 MB LOW CENTERED NEAR 10N47W. ASIDE FROM
THE CONVECTION RELATED TO THE TROPICAL WAVES AND SPECIAL FEATURE
LOW...SCATTERED MODERATE CONVECTION IS FROM 05N-16N AND E OF
32W...AND FROM 06N-14N BETWEEN 42W-47W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER-LEVEL TROUGH EXTENDS ACROSS EASTERN US SUPPORTING A
FRONTAL SYSTEM ACROSS THE GULF OF MEXICO ANALYZED AS A
STATIONARY FRONT FROM 25N94W TO 26N89W AND AS A COLD FRONT FROM
26N89W TO 27N83W. SCATTERED MODERATE CONVECTION IS OBSERVED
WITHIN 120 NM AHEAD AND BEHIND THESE BOUNDARIES. TO THE SW...A
1010 MB LOW IS CENTERED NEAR 22N97W WITH A SURFACE TROUGH
EXTENDING FROM 25N97W TO 19N95W. UPPER-LEVEL DIFFLUENCE IS
OBSERVED ACROSS THIS AREA WHICH SUPPORTS SCATTERED MODERATE
CONVECTION FROM 20N-24N AND W OF 96W. SCATTEROMETER DATA DEPICTS
A GENTLE TO MODERATE NORTHERLY FLOW ACROSS THE NORTHERN HALF OF
THE BASIN WHILE A LIGHT TO GENTLE SOUTHERLY FLOW PREVAILS ACROSS
THE SOUTHERN GULF S OF 26N. OVER THE NEXT 24 HOURS...THE FRONT
IS EXPECTED TO STALL ACROSS THE CENTRAL GULF  BEFORE LIFTING N
AND BECOMING DIFFUSE AS SHOWERS AND THUNDERSTORMS WILL PULSE
ALONG THE DYING FRONTAL BOUNDARY.

CARIBBEAN SEA...

THE MAIN FEATURE CURRENTLY CAUSING CONVECTION ACROSS THE
NORTHERN CARIBBEAN IS AN UPPER-LEVEL LOW CENTERED OVER N OF
HISPANIOLA NEAR 21N72W. ISOLATED MODERATE CONVECTION PREVAILS N
OF 17N BETWEEN 68W-81W AFFECTING PORTIONS OF
HISPANIOLA...CUBA...JAMAICA AS WELL AS THEIR ADJACENT WATERS.
ISOLATED CONVECTION IS ALSO OBSERVED ACROSS THE LESSER ANTILLES
AND THE E CARIBBEAN WATERS MAINLY E OF 64W. TO THE S...THE
PROXIMITY OF THE MONSOON TROUGH CURRENTLY OVER PANAMA IS
ENHANCING CONVECTION ACROSS THE WATERS S OF 10N BETWEEN 77W-83W.
SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE TRADES ACROSS THE
BASIN. OVER THE NEXT 24 HOURS...EXPECT A SIMILAR WEATHER PATTERN
ACROSS THE BASIN.

...HISPANIOLA...

A TROPICAL WAVE IS MOVING ACROSS THE WINDWARD PASSAGE. AN UPPER-
LEVEL LOW IS CENTERED N OF THE ISLAND SUPPORTING ISOLATED
MODERATE CONVECTION ACROSS THE AREA AND ADJACENT WATERS. THIS
ACTIVITY IS EXPECTED TO CONTINUE OVER THE NEXT 24 HOURS AS THE
UPPER-LEVEL LOW WILL CONTINUE OVER THE AREA.

ATLANTIC OCEAN...

MIDDLE TO UPPER LEVEL ENERGY ASSOCIATED WITH LONGWAVE TROUGHING
OVER THE EASTERN CONUS IS SUPPORTING A COLD FRONT THAT EXTENDS
FROM 29N81W TO 33N77W. AS OF 2100 UTC...A PRE-FRONTAL TROUGH WAS
ANALYZED FROM THE FLORIDA STRAITS NEAR 24N82W TO 30N76W.
SCATTERED MODERATE CONVECTION IS OBSERVED ALONG THESE BOUNDARIES
AFFECTING THE AREA W OF 73W. TO THE SE...A SURFACE TROUGH WAS
ANALYZED N OF HISPANIOLA FROM 24N66W TO 19N69W. ANOTHER SURFACE
TROUGH WAS ANALYZED FROM 29N44W TO 24N49W. ISOLATED SHOWERS IS
EXPECTED ALONG THESE BOUNDARIES. THE REMAINDER OF THE BASIN IS
UNDER THE INFLUENCE OF A 1027 MB SURFACE HIGH CENTERED NEAR
38N35W AND EXTENDING S ACROSS THE CENTRAL AND EASTERN TROPICAL
ATLANTIC.

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

$$

ERA
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