[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 151752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT AUG 15 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
17N22W TO 06N22W...MOVING W AT 15 TO 20 KT OVER THE PAST 24
HOURS. A 1012 MB LOW IS CENTERED NEAR 10N22W ALONG THE WAVE IN
THE VICINITY OF THE MONSOON TROUGH. SSMI TPW IMAGERY INDICATES
HIGH MOISTURE IS IN THE WAVE ENVIRONMENT. AN INVERTED 700 MB
TROUGH IS INDICATED IN MODEL FIELDS BETWEEN 17W AND 27W.
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION ARE FROM 08N
TO 14N BETWEEN 19W AND 27W.

A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AN AXIS THAT
EXTENDS FROM 20N44W TO 10N45W...MOVING W AT 15 TO 20 KT OVER THE
PAST 24 HOURS. MODELS INDICATE A N-S ELONGATED INVERTED 700 MB
TROUGH BETWEEN 40W AND 50W. SSMI TPW INDICATES THIS WAVE IS IN A
DRY ENVIRONMENT. NO DEEP CONVECTION CURRENTLY NOTED WITH THIS
WAVE.

A TROPICAL WAVE OVER THE WESTERN ATLC TO EASTERN CARIBBEAN HAS
AN AXIS THAT EXTENDS FROM 21N64W TO 10N66W...MOVING W AT 10 TO
15 KT OVER THE PAST 24 HOURS. MODERATE TO HIGH MOISTURE
ACCOMPANIES THIS WAVE. THIS WAVE ALSO COINCIDES WITH A SUBTLE
700 MB INVERTED TROUGH BETWEEN 64W AND 72W. SCATTERED MODERATE
CONVECTION IS FROM 17N TO 21N BETWEEN 59W AND 65W...WITH DEEP
LAYER SW SHEAR BEGINNING TO IMPACT THE WAVE. SCATTERED SHOWERS
ARE WITHIN 100 NM OF THE WAVE AXIS ELSEWHERE.

A TROPICAL WAVE EXTENDS FROM THE SW GULF...ACROSS MEXICO...AND
OVER THE E PACIFIC WITH AN AXIS EXTENDING FROM 20N92W TO 09N93W.
NO CONVECTION IS NOTED WITH THIS WAVE OVER THE GULF OF MEXICO.
ADDITIONAL INFORMATION REGARDING THIS WAVE CAN BE FOUND UNDER
THE PACIFIC TROPICAL WEATHER DISCUSSION UNDER AWIPS HEADER
MIATWDEP.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
A 1012 MB LOW NEAR 10N22W TO 09N30W WHERE THE ITCZ BEGINS AND
CONTINUES TO 09N40W TO 07N50W TO THE COAST OF S AMERICA NEAR
07N59W. OTHER THAN THE CONVECTION ASSOCIATED WITH THE EASTERN
ATLC TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS FROM 05N
TO 10N BETWEEN 39W AND 50W.

...DISCUSSION...

...GULF OF MEXICO...

A MID TO UPPER TROUGH OVER THE EASTERN US EXTENDS TO THE N GULF
COAST E FROM LOUISIANA TO THE FL PANHANDLE...THEN E OVER THE
EXTREME W ATLC. THIS SUPPORTS A PAIR OF SURFACE TROUGHS OVER THE
NORTHERN GULF. THE NORTHERNMOST TROUGH WAS FORMERLY A STATIONARY
FRONT THAT NOW EXTENDS FROM 30N95W TO 30N88W TO 31N80W. THE
SOUTHERNMOST TROUGH EXTENDS FROM 29N95W TO 28N89W. SCATTERED
THUNDERSTORMS ARE WITHIN 125 NM S OF THE NORTHERN MOST TROUGH.
THE COMBINATION OF UPPER LEVEL DIFFLUENCE AND DEEP MOISTURE
SUPPORTS ISOLATED MODERATE CONVECTION WITH SCATTERED SHOWERS AND
THUNDERSTORMS FROM 22N TO 28N BETWEEN 80W AND 90W. GENERALLY WEAK
LOW LEVEL FLOW COVERS THE GULF BASIN WITH MAINLY GENTLE SURFACE
WINDS PRESENT...EXCEPT GUSTY NEAR CONVECTION. OVER THE NEXT 24
HOURS EXPECT ONGOING CONVECTION MAINLY N OF 24N WITH THE
PRESENCE OF SURFACE TROUGHING AND DEEP MOISTURE.

CARIBBEAN SEA...

AN UPPER LEVEL ANTICYCLONE CENTERED OVER THE CENTRAL CARIBBEAN
DOMINATES MUCH OF THE BASIN ALOFT. UPPER LEVEL DIFFLUENCE AROUND
THE PERIPHERY OF THE RIDGE OVER THE SW CARIBBEAN COMBINED WITH
DEEP MOISTURE AND THE NEARBY E PAC MONSOON TROUGH SUPPORTS
ISOLATED MODERATE CONVECTION S OF 12N W OF 76W. A TROPICAL WAVE
IS OVER THE EASTERN CARIBBEAN. PLEASE REFER TO THE TROPICAL
WAVES SECTION FOR MORE DETAILS. MODERATE TO FRESH TRADE WINDS
ARE OVER THE S CENTRAL CARIBBEAN S OF 15N. GENTLE TO MODERATE
TRADE WINDS COVER THE REMAINDER OF THE CARIBBEAN. OVER THE NEXT
24 HOURS EXPECT CONVECTION TO BE POSSIBLE NEAR THE TROPICAL WAVE
CURRENTLY OVER THE E CARIBBEAN AS IT CONTINUES W ACROSS THE
CENTRAL CARIBBEAN. CONVECTION WILL ALSO CONTINUE OVER THE SW
CARIBBEAN.

...HISPANIOLA...

MOISTURE WILL INCREASE OVER THE ISLAND LATE TODAY AS A TROPICAL
WAVE APPROACHES FROM THE EAST. EXPECT SHOWERS AND THUNDERSTORMS
ACROSS SPREADING E TO W ACROSS THE ISLAND TONIGHT. THE PRESENCE
OF MOISTURE ASSOCIATED WITH THE WAVE WILL SUPPORT SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY AFTERNOON.

ATLANTIC OCEAN...

AN UPPER TROUGH OVER THE E US SUPPORTS A SURFACE TROUGH FROM
31N80W TO N FL. A WEAK UPPER LOW IS CENTERED OVER THE NORTHERN
BAHAMAS. THE COMBINATION OF THESE TWO FEATURES WITH DEEP
MOISTURE SUPPORTS SCATTERED THUNDERSTORMS FROM 23N TO 31N
BETWEEN 76W AND 82W. FARTHER EAST...A PAIR OF SURFACE TROUGHS
ARE OVER THE CENTRAL ATLC. ONE EXTENDS FROM 30N57W TO
28N63W...AND THE OTHER FROM 28N51W TO 24N50W. SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS ARE WITHIN 125NM OF EITHER SIDE OF
THE WESTERNMOST TROUGH. ONE TROPICAL WAVE EXTENDS FROM THE
EASTERN CARIBBEAN TO W ATLC. TWO OTHER TROPICAL WAVES ARE OVER
THE CENTRAL AND EASTERN ATLC RESPECTIVELY. PLEASE REFER TO THE
TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS
EXPECT CONVECTION TO CONTINUE TO BE POSSIBLE FROM THE N BAHAMAS
N TO 31N.

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

$$
LATTO
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