[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112335
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI SEP 11 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
2330 UTC.

...SPECIAL FEATURES...

THE REMNANTS OF HENRI ARE CENTERED NEAR 40.0N 58.5W AT 11/2100
UTC OR ABOUT 465 NMI SSW OF CAPE RACE NEWFOUNDLAND MOVING NNE AT
21 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM
SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 40 KT. SCATTERED
MODERATE CONVECTION IS FROM 40N-44N BETWEEN 54W-57W. FOR MORE
INFORMATION SEE LAST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT3/WTNT23 KNHC.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLANTIC WITH AXIS EXTENDING FROM
16N22W TO 08N24W...MOVING W AT 15 KT. THE WAVE COINCIDES WITH
LOW AMPLITUDE 700 MB TROUGHING S OF 13N AND E OF 23W. SSMI TPW
IMAGERY INDICATES THE WAVE IS EMBEDDED IN A ENVIRONMENT OF
MODERATE TO HIGH MOISTURE. NO SIGNIFICANT CONVECTION IS OBSERVED
WITH THIS FEATURE AT THIS TIME.

A TROPICAL WAVE IS ACROSS THE CENTRAL ATLANTIC WITH AXIS
EXTENDING FROM 18N39W TO 10N41W...MOVING W AT 15 KT. THE WAVE
COINCIDES WITH A BROAD 700 MB TROUGH BETWEEN 33W-50W. THIS WAVE
IS ALSO EMBEDDED IN AN ENVIRONMENT OF MODERATE TO HIGH
MOISTURE...WITH HIGHER CONCENTRATIONS S OF 16N. SCATTERED
MODERATE CONVECTION IS FROM 08N-14N BETWEEN 39W-43W.

A TROPICAL WAVE...INCLUDING THE REMNANTS OF GRACE... IS OVER THE
E CARIBBEAN WITH AXIS EXTENDING FROM 20N64W TO 12N64W...MOVING W
AT 15 TO 20 KT. THE WAVE COINCIDES WITH A 700 MB TROUGH BETWEEN
60W AND 65W...AND A 850 MB RELATIVE VORTICITY MAXIMUM NEAR
17N63W. SCATTERED TO NUMEROUS MODERATE CONVECTION PREVAILS E OF
THE WAVE AXIS AFFECTION THE LESSER ANTILLES FROM 13N-23N BETWEEN
58W-64W.

A TROPICAL WAVE EXTENDS ACROSS THE W CARIBBEAN WITH AXIS FROM
17N75W TO 08N77W...MOVING W AT 15 TO 20 KT. THE WAVE COINCIDES
WITH SUBTLE 700 MB TROUGHING BETWEEN 70W AND 76W. SCATTERED
MODERATE CONVECTION IS FROM 08N TO 16N BETWEEN 73W AND 84W. SOME
OF THIS CONVECTION IS ALSO ASSOCIATED WITH THE EASTERN PACIFIC
MONSOON TROUGH.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N15W TO
08N24W TO 10N40W. THE ITCZ BEGINS W OF A TROPICAL WAVE NEAR
10N43W AND CONTINUES TO 06N56W. OTHER THAN CONVECTION ASSOCIATED
WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM
06N-14N BETWEEN 43W-54W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD UPPER-LEVEL TROUGH EXTENDS FROM THE CENTRAL AND EASTERN
US TO THE N GULF COAST. SHORTWAVE ENERGY ALOFT MOVING AROUND THE
BASE OF THIS TROUGH IS SUPPORTING CLUSTERS OF MODERATE TO STRONG
CONVECTION OVER THE NORTHERN GULF N OF 25N. A 1016 MB SURFACE
HIGH IS CENTERED NEAR 28N86W SUPPORTING MAINLY GENTLE TO
MODERATE ANTICYCLONIC WINDS ACROSS THE BASIN...WITH THE
EXCEPTION OF VARIABLE AND GUSTY WINDS IN THE VICINITY OF
CONVECTION OVER THE N GULF. OVER THE NEXT 24 HOURS...EXPECT FOR
THE UPPER-LEVEL TROUGH TO DIG S AND E SUPPORTING CONVECTION
ACROSS THE NORTHERN GULF WATERS.

CARIBBEAN SEA...

TWO TROPICAL WAVES ARE MOVING ACROSS THE CARIBBEAN. PLEASE REFER
TO THE TROPICAL WAVES SECTION FOR DETAILS. AN ELONGATED UPPER-
LEVEL ANTICYCLONE IS CENTERED OVER THE YUCATAN PENINSULA AND
EXTENDS E ACROSS THE W CARIBBEAN MAINLY W OF 76W. ANOTHER AREA
OF UPPER-LEVEL DIFFLUENCE PREVAILS OVER CUBA AND THE NW
CARIBBEAN SUPPORTING SCATTERED MODERATE CONVECTION ACROSS THE
ISLAND AND ADJACENT WATERS. TO THE E...AN UPPER-LEVEL CYCLONE IS
CENTERED NEAR 16N70W AND EXTENDS ACROSS THE REMAINDER OF THE
BASIN. THESE FEATURES ARE GENERATING UPPER-LEVEL DIFFLUENCE THAT
SUPPORTS SCATTERED MODERATE CONVECTION S OF 13N BETWEEN 73W-83W.
GENTLE TO MODERATE TRADES COVER THE MAJORITY OF THE CARIBBEAN
BASIN EXCEPT A SMALL AREA OF MODERATE TO FRESH ALONG THE
NORTHERN PORTION OF THE WAVE CURRENTLY OVER THE EASTERN
CARIBBEAN. OVER THE NEXT 24 HOURS...EXPECT FOR THE WAVES TO
CONTINUE MOVING W SUPPORTING CONVECTION. CONVECTION IS EXPECTED
TO PREVAIL ACROSS THE SOUTHERN CARIBBEAN DUE TO THE PROXIMITY OF
THE MONSOON TROUGH.

...HISPANIOLA...

ISOLATED CONVECTION IS OBSERVED ACROSS THE CENTRAL PORTION OF
THE ISLAND. THIS ACTIVITY WILL DISSIPATE LATER THIS EVENING. A
TROPICAL WAVE WILL APPROACH THE ISLAND SUPPORTING SCATTERED
MODERATE CONVECTION OVER THE NEXT 24-48 HOURS. LOCALLY HEAVY
RAINFALL IS POSSIBLE.

ATLANTIC OCEAN...

TWO TROPICAL WAVES ARE MOVING ACROSS THE TROPICAL ATLANTIC.
PLEASE REFER TO THE SECTION ABOVE FOR DETAILS. A SURFACE RIDGE
EXTENDS ACROSS THE WHOLE BASIN ANCHORED BY A 1020 MB HIGH
CENTERED NEAR 28N28W. UPPER-LEVEL DIFFLUENCE IS SUPPORTING
ISOLATED CONVECTION ACROSS THE ATLANTIC WATERS W OF 50W. A
WEAKNESS IN THE RIDGE WAS ANALYZED AS A 1016 MB SURFACE LOW
CENTERED NEAR 27N38W. THIS LOW HAS A SURFACE TROUGH THAT EXTENDS
FROM 30N36W TO THE LOW CENTER TO 26N40W. ISOLATED CONVECTION IS
OBSERVED FROM 27N-30N BETWEEN 37W-40W. THE REMNANTS OF HENRI ARE
OVER THE WEST CENTRAL ATLANTIC. PLEASE REFER TO THE SPECIAL
FEATURES SECTION FOR MORE DETAILS. SCATTEROMETER DATA DEPICTS A
GENTLE TO MODERATE ANTICYCLONIC FLOW PREVAILING ACROSS THE
BASIN. EXPECT A SIMILAR WEATHER PATTERN TO PREVAIL OVER THE NEXT
24 HOURS.

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

$$

ERA
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