[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131745
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

AN EASTERN ATLC TROPICAL WAVE HAS AN AXIS THAT EXTENDS FROM
19N31W TO 09N32W...MOVING W AT 10 TO 15 KT OVER THE PAST 24
HOURS. A LARGE MID LEVEL GYRE NEAR 10N31W ACCOMPANIES THIS WAVE.
MUCH OF THIS WAVE IS EMBEDDED IN DRY AIR N OF 09N. ISOLATED
MODERATE CONVECTION IS FROM 05N TO 08N BETWEEN 31W AND 35W.

A CENTRAL ATLC TROPICAL WAVE HAS AN AXIS THAT EXTENDS FROM
17N51W TO 06N54W...MOVING W AT 10 TO 15 KT OVER THE PAST 24
HOURS. A 700 MB INVERTED TROUGH IS EVIDENT BETWEEN 51W AND 59W.
A SURGE OF DEEP MOISTURE ACCOMPANIES THIS WAVE. SCATTERED
MODERATE CONVECTION IS WITHIN 200 NM E OF THE WAVE AXIS S OF
15N.

A WESTERN CARIBBEAN TROPICAL WAVE EXTENDS FROM 19N81W TO
08N81W...MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS. A BROAD
700 MB TROUGH IS INDICATED BETWEEN 78W AND 87W. THIS WAVE IS
EMBEDDED IN AN ENVIRONMENT OF MODERATE MOISTURE. ISOLATED
MODERATE CONVECTION IS FROM 09N TO 16N BETWEEN 78W AND 85W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL AFRICA NEAR 14N17W TO
09N30W. THE ITCZ BEGINS W OF A TROPICAL WAVE NEAR 08N33W AND
CONTINUES TO 07N52W. OTHER THAN CONVECTION ASSOCIATED WITH THE
EASTERN ATLC TROPICAL WAVE...ISOLATED MODERATE CONVECTION IS
FROM 06N TO 09N BETWEEN 37W AND 50W.

...DISCUSSION...

...THE GULF OF MEXICO...

ANTICYCLONIC UPPER LEVEL FLOW COVERS THE WESTERN GULF WHILE AN
UPPER TROUGH EXTENDS ALONG THE EASTERN US COAST TO N FL TO THE
EXTREME EASTERN GULF TO AROUND 16N. THIS TROUGH SUPPORTS A
STATIONARY FRONT THAT EXTENDS ACROSS CENTRAL FLORIDA NEAR
30N82W...ACROSS THE NE GULF...TO LOUISIANA NEAR 30N90W. A PRE-
FRONTAL SURFACE TROUGH EXTENDS FROM 29N82W TO 28N96W. ISOLATED
MODERATE CONVECTION IS FROM 27N TO 29N BETWEEN 93W AND 96W.
CLOSER TO THE BASE OF THE UPPER TROUGH AND UPPER LEVEL
DIFFLUENCE...SCATTERED THUNDERSTORMS ARE OVER THE NE GULF FROM
25N TO 29N BETWEEN 82W AND 91W. GENTLE TO MODERATE SURFACE WINDS
COVER THE GULF BASIN. OVER THE NEXT 24 HOURS CONVECTION WILL
CONTINUE PRIMARILY ALONG AND S OF THE SURFACE TROUGH. THE
STATIONARY FRONT WILL DISSIPATE THROUGH TONIGHT.

...THE CARIBBEAN SEA AND HISPANIOLA...

A BROAD UPPER LEVEL LOW IS CENTERED NEAR 19N78W OVER THE
NORTHERN CARIBBEAN. FLOW AROUND THIS UPPER LOW DOMINATES THE
CARIBBEAN BASIN. DYNAMIC LIFT AROUND THE CENTER OF THE UPPER LOW
SUPPORTS ISOLATED MODERATE CONVECTION FROM 17N TO 22N BETWEEN
73W AND 87W. A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN.
PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. THE
UPPER LOW SUPPORTS A SURFACE TROUGH THAT EXTENDS FROM 18N73W TO
13N72W. NO DEEP CONVECTION IS NOTED WITH THIS TROUGH. THE
PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE WESTERN ATLC
AND LOW PRESSURE OVER COLOMBIA SUPPORTS MODERATE TO FRESH TRADE
WINDS OVER THE CENTRAL CARIBBEAN...WITH A SMALL AREA OF STRONG
TRADE WINDS NEAR THE COAST OF COLOMBIA BETWEEN 74W TO 76W.
GENTLE TO MODERATE TRADE WINDS ARE OCCURRING ELSEWHERE OVER THE
CARIBBEAN. OVER THE NEXT 24 HOURS THE WESTERN CARIBBEAN TROPICAL
WAVE WILL MOVE INLAND OVER CENTRAL AMERICA. CONVECTION AHEAD OF
A TROPICAL WAVE OVER THE CENTRAL CARIBBEAN WILL BEGIN TO AFFECT
THE LEEWARD ISLANDS FRIDAY MORNING.

THE ATLANTIC OCEAN...

AN UPPER TROUGH ALONG THE EASTERN US COAST SUPPORTS A COLD FRONT
N OF OUR AREA THAT TRANSITIONS TO A STATIONARY FRONT FROM 31N80W
TO N FL. THE COMBINATION OF PRE-FRONTAL FORCING AND UPPER LEVEL
DIFFLUENCE SUPPORTS CLUSTERS OF MODERATE CONVECTION AND
SCATTERED THUNDERSTORMS FROM 24N TO 31N BETWEEN 75W AND THE FL
PENINSULA...AND ISOLATED MODERATE CONVECTION FROM 28N TO 31N
BETWEEN 69W AND 75W. FARTHER EAST...A BROAD UPPER LOW CENTERED
NEAR 27N57W HAS A SURFACE REFLECTION IN THE FORM OF A SURFACE
TROUGH THAT EXTENDS FROM 30N54W TO 24N40W. ISOLATED MODERATE
CONVECTION IS FROM 26N TO 31N BETWEEN 51W AND 58W. A NON
TROPICAL LOW VOID OF CONVECTION IS CENTERED OFF THE AFRICAN
COAST NEAR 25N20W WITH A SURFACE TROUGH EXTENDING FROM 28N18W TO
19N20W. TWO TROPICAL WAVES ARE OVER THE TROPICAL NORTHERN ATLC.
PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS.
OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE AS THE
STATIONARY FRONT TRANSITIONS TO A SURFACE TROUGH OFFSHORE OF N
FL.

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

$$
LATTO
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