[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI AUG 14 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 W AFRICAN TROPICAL WAVE EMERGED OFF THE COAST WITH AXIS FROM
15N18W TO 09N15W. OBSERVATIONS SHOW A 4 MB DROP IN SURFACE
PRESSURE AS THE WAVE HAS PASSED LOCATIONS OVER W
AFRICA...INDICATING A WELL DEFINED WAVE REACHING THE SURFACE. A
CLUSTER OF MODERATE TO STRONG CONVECTION IS FROM 09N-14N AND E
OF 23W.

A CENTRAL ATLC TROPICAL WAVE HAS AN AXIS THAT EXTENDS FROM
20N39W TO 08N41W...MOVING W AT 15 TO 20 KT OVER THE PAST 24
HOURS. THIS WAVE IS EMBEDDED IN DRY AIR N OF 09N. A 700 MB GYRE
IS EVIDENT ALONG THE WAVE AXIS NEAR 16N41W. ISOLATED MODERATE
CONVECTION IS S OF 09N BETWEEN 40W AND 42W.

A CENTRAL ATLC TROPICAL WAVE IS APPROACHING THE E CARIBBEAN WITH
AN AXIS THAT EXTENDS FROM 20N60W TO 10N61W...MOVING W AT 15 TO
20 KT OVER THE PAST 24 HOURS. THIS WAVE HAS BEEN EVIDENT ON
RADAR THIS MORNING AND A RECENT WIND SHIFT FROM ENE TO SE WAS
NOTED AT BARBADOS. ISOLATED MODERATE CONVECTION IS FROM 15N-
19N BETWEEN 57W-62W.

A TROPICAL WAVE EXTENDS FROM THE WESTERN CARIBBEAN NEAR
18N86W...ACROSS CENTRAL AMERICA...TO THE EASTERN PACIFIC NEAR
08N87W...MOVING W AT 10 TO 15 KT OVER THE PAST 24 HOURS. AN
INVERTED 700 MB TROUGH IS INDICATED BETWEEN 80W AND 90W . THE
NORTHERN PORTION OF THIS WAVE IS INTERACTING WITH AN UPPER-LEVEL
LOW CENTERED NEAR THE CAYMAN ISLANDS...WHILE THE SOUTHERN
PORTION OF THE WAVE INTERACTING WITH DEEP TROPICAL MOISTURE.
ISOLATED MODERATE CONVECTION IS N OF 16N W OF 80W. CLUSTERS OF
MODERATE TO STRONG CONVECTION ARE S OF 16N W OF 83W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH BEGINS W OF A TROPICAL WAVE NEAR 12N19W TO
10N27W. THE ITCZ BEGINS FROM THIS POINT TO 07N44W TO 09N60W.
ASIDE FROM HE CONVECTION RELATED TO THE TROPICAL
WAVES...ISOLATED CONVECTION IS FROM 05N-09N BETWEEN 43W-55W.

...DISCUSSION...

...GULF OF MEXICO...

A MID TO UPPER-LEVEL TROUGH ALONG THE EASTERN US COAST TO W
CENTRAL FL SUPPORTS A STATIONARY FRONT THAT EXTENDS ACROSS N FL
TO 30N86W TO 30N90W. THE UPPER TROUGH ALSO SUPPORTS A WEAK 1012
MB LOW CENTERED NEAR 28N85W WITH A SURFACE TROUGH THAT EXTENDS
FROM THE LOW TO 26N89W. TO THE SW...A 1018 MB SURFACE HIGH IS
CENTERED NEAR 22N93W. UPPER-LEVEL DIFFLUENCE AND ABUNDANT
MOISTURE ARE SUPPORTING SCATTERED MODERATE CONVECTION ACROSS THE
BASIN. SCATTEROMETER DATA DEPICTS A LIGHT TO GENTLE NORTHERLY
FLOW PREVAILING ACROSS THE NORTHERN HALF OF THE GULF WHILE A
LIGHT ANTICYCLONIC FLOW PREVAILS ACROSS THE SOUTHERN PORTION.
OVER THE NEXT 24 HOURS...EXPECT CONVECTION TO CONTINUE OVER THE
NORTHERN GULF WHILE THE SURFACE HIGH/LOW WILL DISSIPATE.

CARIBBEAN SEA...

AN UPPER-LEVEL LOW IS CENTERED OVER THE CAYMAN ISLANDS NEAR
19N81W. THIS LOW IS INTERACTING WITH A TROPICAL WAVE OVER THE
WESTERN CARIBBEAN SUPPORTING CONVECTION OVER THE W CARIBBEAN
MAINLY W OF 80W. ADDITIONAL CONVECTION PREVAILS OVER THE S
CARIBBEAN S OF 13 BETWEEN 79W-84W AFFECTING COSTA RICA AND
NICARAGUA. GENERALLY FAIR WEATHER COVERS THE REMAINDER OF THE
CARIBBEAN TODAY WITH GENTLE TO MODERATE TRADE WINDS EXCEPT
MODERATE TO FRESH WINDS S OF 14N BETWEEN 67W-75W. OVER THE NEXT
24 HOURS...CONVECTION WILL CONTINUE OVER THE W CARIBBEAN. THE
NEXT TROPICAL WAVE WILL ENTER THE E CARIBBEAN INCREASING THE
MOISTURE AND SUPPORTING CONVECTION ACROSS THE LESSER ANTILLES
AND PUERTO RICO.

...HISPANIOLA...

MODERATE MOISTURE PREVAILS ACROSS THE ISLAND WITH AN UPPER-LEVEL
LOW CENTERED TO THE W SUPPORTING ISOLATED CONVECTION THIS
AFTERNOON INTO THE EVENING. GENERALLY FAIR WEATHER IS EXPECTED
OVERNIGHT. A TROPICAL WAVE WILL APPROACH THE ISLAND INCREASING
THE MOISTURE AND THE CHANCES FOR SHOWERS AND THUNDERSTORMS
ACROSS THE AREA.

ATLANTIC OCEAN...

THE MID TO UPPER-LEVEL TROUGH ALONG THE EASTERN US SUPPORTS A
STATIONARY FRONT THAT ENTERS OUR AREA OF DISCUSSION FROM 31N74W
TO 30N81W. A PRE-FRONTAL TROUGH EXTENDS FROM 27N79W TO 30N77W.
ISOLATED MODERATE CONVECTION PREVAILS W OF 70W. FARTHER EAST...A
SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC EXTENDING FROM
29N52W TO 22N45W. NO DEEP CONVECTION IS NOTED WITH THIS TROUGH.
ANOTHER DRY SURFACE TROUGH IS FROM 26N41W TO 23N39W. THREE
TROPICAL WAVES ARE OVER THE TROPICAL N ATLANTIC. PLEASE SEE THE
TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24
HOURS...CONVECTION WILL CONTINUE NEAR THE NORTHERN
BAHAMAS WHILE THE STATIONARY FRONT WILL BEGIN TO WEAKEN.

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

$$

ERA
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