[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181743
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED AUG 18 2010

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS W OF THE CAPE VERDE ISLANDS EXTENDING ALONG
26N26W 18N27W 10N26W MOVING W NEAR 10 KT. LOW-LEVEL CYCLONIC
FLOW IS ABOUT THE WAVE AXIS EVIDENT IN VISIBLE SATELLITE IMAGERY
AND CONFIRMED BY AN ASCAT SCATTEROMETER PASS. THIS WAVE ALSO
COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE INDICATED BY
TOTAL PRECIPITABLE WATER IMAGERY. CONVECTION IS EMBEDDED WITHIN
THE ITCZ WHERE SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
W OF THE WAVE AXIS FROM 11N-13N BETWEEN 28W-33W.

TROPICAL WAVE IS IN THE CENTRAL ATLC EXTENDING FROM 29N38W TO
11N37W MOVING W NEAR 15 KT. A LARGE SURGE OF DEEP LAYER MOISTURE
IS E OF THE WAVE AXIS...WHILE SIGNIFICANT DRY AIR IS WRAPPING
AROUND THE WRN SIDE SUPPRESSING ANY CONVECTION NEAR THE WAVE.

TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN FROM THE
CENTRAL BAHAMAS NEAR 23N76W ACROSS ERN CUBA AND JAMAICA TO NRN
COLOMBIA NEAR 10N74W MOVING W 15-20 KT. VISIBLE SATELLITE
IMAGERY INDICATES BROAD CYCLONIC FLOW IN THE VICINITY OF THE
WAVE AXIS. THE WAVE ALSO COINCIDES WITH AN AREA OF ENHANCED
MOISTURE ACROSS THE CENTRAL CARIBBEAN EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY. CLUSTERS OF NUMEROUS STRONG
CONVECTION ARE FROM 15N-17N BETWEEN 71W-74W...AND FROM 16N-18N
BETWEEN 74W-77W BEGINNING TO IMPACT JAMAICA. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-16N BETWEEN
74W-78W...AND S OF CUBA FROM 19N-21N BETWEEN 77W-84W. ISOLATED
MODERATE CONVECTION IS ALSO FROM 9N-18N BETWEEN 78-83W...AND N
OF CUBA FROM 22N-25N BETWEEN 77W-81W. MUCH OF THE ACTIVITY IS
FURTHER ENHANCED BY AN UPPER LEVEL TROUGH EXTENDING FROM THE
YUCATAN CHANNEL TO THE NRN COAST OF COLOMBIA.

...THE ITCZ...

ITCZ AXIS IS CENTERED FROM LIBERIA 7N11W ALONG 9N19W 12N31W
12N44W 6N58W. AN AREA OF NUMEROUS MODERATE/SCATTERED STRONG
CONVECTION HAS MOVED OFF THE W AFRICAN COAST FROM 9N-18N BETWEEN
16W-20W ASSOCIATED WITH THE NEXT TROPICAL WAVE THAT SHOULD MOVE
OFF THE COAST DURING THE NEXT DAY OR SO. SCATTERED MODERATE
CONVECTION IS MAINLY S OF THE ITCZ AXIS FROM 3N-6N BETWEEN
11W-20W...FROM 4N-9N BETWEEN 23N-29N...FROM 6N-10N BETWEEN
31N-38W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
7N-10N BETWEEN 38W-48W.

...DISCUSSION...

THE GULF OF MEXICO...
SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE NRN GULF N OF 28N
W OF 84W MAINLY CONCENTRATED S OF SW LOUISIANA. THIS ACTIVITY IS
ASSOCIATED WITH AN AREA OF LOW PRESSURE OVER WRN MISSISSIPPI.
TOTAL PRECIPITABLE WATER IMAGERY INDICATES ENHANCED MOISTURE
ACROSS MUCH OF THE WRN GULF WITH MAXIMUM VALUES NEAR THE
HEAVIEST SHOWERS S OF LOUISIANA. ISOLATED SHOWERS/THUNDERSTORMS
ARE ALSO FROM 25N-28N BETWEEN 88W-96W. A SURFACE TROUGH EXTENDS
FROM THE BAY OF CAMPECHE ACROSS SRN MEXICO INTO THE E PACIFIC
ALONG 22N93W TO 11N92W. ISOLATED SHOWERS/THUNDERSTORMS ARE W OF
THE AXIS S OF 23N W OF 94W. THE REMAINDER OF THE BASIN IS
EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF AN
UPPER LEVEL RIDGE COVERING THE AREA CENTERED OVER WRN TEXAS.
EXPECT CONTINUED SHOWER ACTIVITY ACROSS THE NRN GULF DURING THE
NEXT 24 HRS WHILE SURFACE RIDGING BEGINS TO BUILD ACROSS THE
BASIN FROM THE W ATLC.

THE CARIBBEAN SEA...
A TROPICAL WAVE EXTENDING FROM THE CENTRAL BAHAMAS TO NRN
COLOMBIA IS IMPACTING MUCH OF THE WRN CARIBBEAN. THE STRONGEST
ACTIVITY IS S OF HAITI/ERN CUBA APPROACHING JAMAICA WHILE
SCATTERED TO ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS THE
REMAINDER OF THE W CARIBBEAN. SEE TROPICAL WAVE SECTION ABOVE
FOR MORE DETAILS. THIS LARGE AREA OF SHOWER ACTIVITY IS FURTHER
SUPPORTED BY A NARROW UPPER LEVEL TROUGH EXTENDING FROM THE
YUCATAN CHANNEL TO NRN COLOMBIA. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE ALSO ACROSS THE SW CARIBBEAN DUE TO SURFACE
CONVERGENCE NEAR A PORTION OF THE ITCZ EXTENDING ACROSS COSTA
RICA ALONG 10N TO NEAR NRN COLOMBIA. A SECOND UPPER LEVEL TROUGH
IS ACROSS THE ERN CARIBBEAN CENTERED E OF THE LEEWARD ISLANDS
NEAR 19N57W. HOWEVER...THIS UPPER TROUGH IS EMBEDDED WITH
SIGNIFICANT DRY AIR MAINTAINING FAIR WEATHER AT THE SURFACE.
VISIBLE SATELLITE IMAGERY ALONG WITH SURFACE DATA FROM THE
LESSER ANTILLES INDICATES AN AREA OF DUST MOVING ACROSS THE ERN
CARIBBEAN E OF 70W WHICH IS FURTHER PROVIDING STABLE CONDITIONS.
EXPECT CONTINUED SHOWER ACTIVITY ACROSS THE WRN CARIBBEAN AS THE
TROPICAL WAVE MOVES WWD.

THE ATLANTIC OCEAN...
SURFACE RIDGING COVERS THE W ATLC AROUND A 1021 MB HIGH NEAR
28N64W PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE AREA
SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED NEAR 35N69. A WEAK
SURFACE TROUGH EXTENDS OFF THE NE COAST OF FLORIDA ALONG 32N76W
TO 29N79W SUPPORTING ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE
OF THE AXIS. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO N OF
CUBA FROM 22N-25N BETWEEN 76W-81W ASSOCIATED WITH A TROPICAL
WAVE ACROSS THE CENTRAL CARIBBEAN. A COLD FRONT LINES THE BORDER
OF THE DISCUSSION AREA ALONG 32N BETWEEN 50W-64W ENHANCING A FEW
ISOLATED SHOWERS/THUNDERSTORMS FROM 29N-31N BETWEEN 60W-66W. A
SURFACE TROUGH IS S OF THE FRONT ALONG 30N53W TO 26N57W
SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS WITHIN 100 NM OF THE
AXIS. AN UPPER LEVEL TROUGH CENTERED E OF THE LEEWARD ISLANDS
NEAR 19N57W SUPPORTS THE SURFACE TROUGH. FARTHER E...SURFACE
RIDING DOMINATES ANCHORED BY A 1025 MB AZORES HIGH NEAR 36N29W
MAINTAINING FAIR WEATHER. SATELLITE IMAGERY ALSO INDICATES AN
AREA OF AFRICAN DUST ACROSS THE S CENTRAL ATLC AND INTO THE E
CARIBBEAN BETWEEN 55W-70W PROVIDING STABLE CONDITIONS.
ALOFT...AN UPPER LEVEL RIDGE IS COVERING THE E ATLC CENTERED
NEAR 25N36W.

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

$$
WALTON/HOLLEY





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