[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 132326
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 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
2315 UTC.

...TROPICAL WAVES...

AN E ATLANTIC TROPICAL WAVE HAS AN AXIS THAT EXTENDS FROM 19N33W
TO 09N33W...MOVING W AT 10 KT OVER THE PAST 24 HOURS. A LARGE
MID-LEVEL GYRE CURRENTLY CENTERED NEAR 17N35W ACCOMPANIES THIS
WAVE. NO CONVECTION IS OBSERVED IN THE VICINITY OF THIS WAVE AS
IT CONTINUES IN AN AREA WHERE A BROAD DRY AIRMASS PREVAILS.

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLANTIC WITH AXIS
EXTENDING FROM 15N54W TO 07N56W...MOVING W AT 10 TO 15 KT OVER
THE PAST 24 HOURS. THIS WAVE IS NOT ONLY NOTICEABLE AT 700 MB
BUT ALSO AT THE SURFACE...AS SEEN IN SCATTEROMETER WINDS...
SURFACE OBSERVATIONS...AND VISIBLE SATELLITE IMAGERY. A SURGE OF
DEEP MOISTURE ACCOMPANIES THIS WAVE...SUPPORTING SCATTERED
MODERATE CONVECTION FROM 10N-15N BETWEEN 52W-57W.

A TROPICAL WAVE CONTINUES OVER THE W CARIBBEAN WITH AXIS
EXTENDING FROM 19N82W TO 08N82W...MOVING W AT 15 TO 20 KT OVER
THE PAST 24 HOURS. A SUBTLE 700 MB TROUGH IS OBSERVED 80W-90W
AND ABUNDANT MOISTURE SURROUNDS THIS WAVE AND PREVAILS ACROSS
THE WHOLE W CARIBBEAN. AN UPPER-LEVEL LOW IS CENTERED W OF
JAMAICA NEAR 19N79W SUPPORTING SCATTERED MODERATE CONVECTION
ACROSS THE W CARIBBEAN AND HENCE SURROUNDING THIS WAVE MAINLY W
OF 80W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL AFRICA NEAR 15N17W TO
09N31W. THE ITCZ BEGINS W OF A TROPICAL WAVE NEAR 09N34W AND
CONTINUES TO 09N52W. OTHER THAN CONVECTION ASSOCIATED WITH THE
TROPICAL WAVE ALONG 54W...ISOLATED MODERATE CONVECTION IS FROM
06N-08N BETWEEN 47W-50W.

...DISCUSSION...

...GULF OF MEXICO...

AN ANTICYCLONIC UPPER-LEVEL FLOW COVERS THE WESTERN GULF WHILE
AN UPPER-LEVEL TROUGH EXTENDS ALONG THE EASTERN US COAST TO N FL
REACHING THE EXTREME EASTERN GULF E OF 86W. THIS TROUGH SUPPORTS
A STATIONARY FRONT THAT EXTENDS FROM THE GULF COAST STATES
ACROSS THE FLORIDA PANHANDLE AND THEN INTO THE W ATLANTIC ALONG
30N. A PRE-FRONTAL SURFACE TROUGH PREVAILS ALONG AND IN THE
VICINITY OF THE SURFACE TROUGH MAINLY N OF 27N. AN AREA OF UPPER-
LEVEL DIFFLUENCE PREVAILS ACROSS THE E GULF REACHING THE FLORIDA
PENINSULA SUPPORTING SCATTERED MODERATE CONVECTION MAINLY E OF
84W. TO THE SW...A 1018 MB SURFACE HIGH IS CENTERED NEAR 23N93W
WHICH SUPPORTS A LIGHT TO GENTLE ANTICYCLONIC FLOW ACROSS THE
BASIN. OVER THE NEXT 24 HOURS...CONVECTION WILL CONTINUE
PRIMARILY ALONG AND S OF THE SURFACE TROUGH. THE STATIONARY
FRONT IS EXPECTED TO DISSIPATE TONIGHT.

CARIBBEAN SEA...

A BROAD UPPER-LEVEL LOW IS CENTERED NEAR 19N79W SUPPORTING
SCATTERED MODERATE CONVECTION ACROSS THE W CARIBBEAN MAINLY W OF
81W. A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN. PLEASE REFER
TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. A STRONG DEEP
LAYER WIND SHEAR PREVAILS ACROSS THE CENTRAL AND E CARIBBEAN
WITH NO SIGNIFICANT CONVECTION OBSERVED AT THIS TIME.
SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE TRADES PREVAILING
ACROSS THE BASIN WITH AN AREAS OF MODERATE TO FRESH WINDS S OF
14N BETWEEN 68W-76W. OVER THE NEXT 24 HOURS THE WESTERN
CARIBBEAN TROPICAL WAVE WILL MOVE INLAND OVER CENTRAL AMERICA.
THE NEXT TROPICAL WAVE WILL APPROACH THE LESSER ANTILLES ON
FRIDAY WITH CONVECTION.

...HISPANIOLA...

THE UPPER LEVEL-LOW CENTERED ACROSS THE W CARIBBEAN IS
SUPPORTING SCATTERED MODERATE CONVECTION ACROSS THE ISLAND. THIS
ACTIVITY WILL CONTINUE THROUGH THE EVENING HOURS. A SIMILAR
WEATHER REGIME WILL PREVAIL OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...

TWO TROPICAL WAVES ARE IN THE TROPICAL ATLANTIC. PLEASE REFER
TO THE SECTION ABOVE FOR MORE DETAILS. AN UPPER-LEVEL TROUGH
ALONG THE EASTERN US COAST SUPPORTS A FRONTAL SYSTEM...ANALYZED
AS A STATIONARY FRONT FROM THE GULF STATES COAST...NORTHERN
FLORIDA...AND THE W ATLANTIC NEAR 31N79W...THEN AS A COLD FRONT
FROM 31N79W TO 34N72W. SCATTERED MODERATE CONVECTION PREVAILS IN
THE VICINITY OF THESE BOUNDARIES W OF 68W. TO THE E...A SURFACE
TROUGH WAS ANALYZED FROM 29N55W TO 26N44W. ISOLATED CONVECTION
PREVAILS ALONG THIS BOUNDARY. THE REMAINDER OF THE BASIN IS
UNDER THE INFLUENCE OF A SURFACE HIGH THAT EXTENDS S FROM THE NE
ATLANTIC. A WEAK 1012 MB SURFACE LOW IS LOCATED NEAR 24N20W WITH
NO SIGNIFICANT CONVECTION. OVER THE NEXT 24 HOURS...CONVECTION
WILL CONTINUE ACROSS THE W ATLANTIC AS THE FRONTAL BOUNDARIES
TRANSITION INTO A SURFACE TROUGH AND PREVAILS IN THE AREA.

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

$$

ERA
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