[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212329
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED AUG 21 2013

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...
TROPICAL WAVE IN THE TROPICAL ATLC EXTENDS FROM 19N37W TO 7N38W
MOVING W-SW 15-20 KT. WAVE IS ALONG THE LEADING EDGE OF A SURGE
OF DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY. A MID LEVEL CYCLONIC CIRCULATION IS THE E OF THE WAVE
AXIS. NO ASSOCIATED SHOWERS/CONVECTION.

TROPICAL WAVE IN THE CARIBBEAN EXTENDS FROM 21N78W TO 11N78W
MOVING W 15-20 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP
MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY.
WAVE IS LOCATED BETWEEN AN UPPER HIGH TO THE E AND AN UPPER LOW
TO THE W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 14N-
20N BETWEEN 71W-80W.

TROPICAL WAVE IN THE GULF OF MEXICO IS NO LONGER DISCERNIBLE AND
WAS DROPPED FROM THE ANALYSIS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 15N17W AND CONTINUES ALONG 14N29W TO 7N50W WHERE THE
ITCZ BEGINS AND CONTINUES INTO SOUTH AMERICA NEAR 6N58W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-10N
BETWEEN 42W-46W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE IS ANCHORED IN THE E PACIFIC REGION EXTENDING A
RIDGE AXIS N ACROSS S MEXICO TO OVER THE W GULF FROM VERACRUZ
MEXICO TO CENTRAL LOUISIANA. AN UPPER LOW IS CENTERED NEAR
HAVANA CUBA AND EXTENDS A TROUGH AXIS TO APALACHEE BAY FLORIDA.
A SURFACE TROUGH EXTENDS FROM FLORIDA BAY NEAR 25N81W TO OVER NE
FLORIDA NEAR CEDAR KEY GENERATING SCATTERED SHOWERS/
THUNDERSTORMS WITHIN 45 NM EITHER SIDE OF THE TROUGH. CLUSTERS
OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE GULF THIS
EVENING MAINLY N OF 23N E OF 94W AND S OF 24N W OF 92W. A WEAK
SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS S GEORGIA INTO THE
GULF TO NEAR 26N93W. SURFACE RIDGE WILL PERSIST THROUGH MON.

CARIBBEAN SEA...
AN UPPER LOW IS CENTERED NEAR HAVANA CUBA COVERING THE NW
CARIBBEAN N OF 17N W OF 80W. AN UPPER RIDGE IS ANCHORED IN THE
CENTRAL CARIBBEAN NEAR 17N77W COVERING THE AREA BETWEEN 70W-80W
AND EXTENDING A RIDGE AXIS S OF THE UPPER LOW OVER THE NW
CARIBBEAN TO OVER CENTRAL AMERICA. THIS UPPER RIDGE IS PROVIDING
DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 11N-15N W OF 80W TO INLAND OVER CENTRAL
AMERICA. THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 11N74W TO
10N84W IN COSTA RICA GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 11N BETWEEN COLOMBIA AND COSTA RICA. A WEAK
SURFACE TROUGH IS OVER THE SE CARIBBEAN EXTENDING FROM 14N61W TO
TO TRINIDAD GENERATING ISOLATED SHOWERS FROM 11N-14N W OF THE
WAVE TO 65W. AFTERNOON THUNDERSTORMS HAVE DEVELOPED INLAND OVER
HISPANIOLA...CUBA...AND JAMAICA. TROPICAL WAVE WILL MOVE W
ACROSS THE W CARIBBEAN TONIGHT AND THU THE ACROSS THE YUCATAN
PENINSULA LATE THU THROUGH FRI.

HISPANIOLA...
AFTERNOON HEATING HAS GENERATE THUNDERSTORMS ACROSS THE ISLAND
THIS EVENING THAT ARE BEGINNING TO MOVE W WITH THE EASTERLY TRADE
WINDS INTO THE WINDWARD PASSAGE. THE UPPER RIDGE OVER THE
CARIBBEAN COVERS THE W END OF THE ISLAND WHILE AN UPPER TROUGH
OVER THE ATLC EXTENDS OVER THE E END GIVING THE ISLAND WESTERLY
FLOW ALOFT. DAILY AFTERNOON SHOWERS/THUNDERSTORMS ARE EXPECTED
TO DEVELOP DUE TO PEAK DAYTIME HEATING AND INSTABILITY.

ATLANTIC OCEAN...
A BROAD UPPER RIDGE COVERS THE W ATLC ANCHORED NEAR 29N70W AND
PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 30N W OF 78W TO INLAND OVER FLORIDA AND CUBA.
A SURFACE RIDGE COVERS THE REMAINDER OF THE W ATLC ANCHORED BY A
1023 MB HIGH NEAR 33N74W. A NARROW UPPER TROUGH EXTENDS INTO THE
W/CENTRAL ATLC NEAR 32N53W AND CONTINUES ALONG 24N58W TO 20N70W
COVERING A PORTION OF HISPANIOLA. THE REMAINDER OF THE ATLC IS
UNDER BENIGN UPPER LEVEL FEATURES WITH A SURFACE RIDGE EXTENDING
FROM A 1022 MB HIGH NEAR THE AZORES COVERING THE REMAINDER OF
THE ATLC BASIN N OF 20N. A WEAK SURFACE TROUGH IS E OF THE
LEEWARD ISLANDS EXTENDING FROM 19N56W TO 14N54W WITH ISOLATED
SHOWERS POSSIBLE WITHIN 90 NM EITHER SIDE OF THE TROUGH. THE N
PORTION OF CARIBBEAN TROPICAL WAVE WILL MOVE ACROSS THE
REMAINDER OF THE FAR SW ATLC AND THEN ACROSS THE STRAITS OF
FLORIDA TONIGHT AND THU. SURFACE RIDGE WILL DRIFT S AND WEAKEN
THU THROUGH SUN AS A WEAK COLD FRONT APPROACHES THE FAR NW
ATLC.

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

$$
PAW


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