[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE AUG 17 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
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS APPROACHING THE CAPE VERDE ISLANDS ALONG 22W S
OF 24N MOVING W ABOUT 10-15 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. A SMALL SURGE OF AFRICAN DUST IS BEHIND THE WAVE
AXIS NEAR 23N. DUE TO THIS AREA OF DRIER AIR...NO DEEP
CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE.

TROPICAL WAVE IS IN THE CENTRAL ATLC EXTENDING FROM 24N32W TO
9N40W MOVING W 15-20 KT. VISIBLE SATELLITE IMAGERY INDICATES
BROAD LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE. A
LARGE SURGE OF DEEP LAYER MOISTURE IS E OF THE WAVE AXIS...WHILE
SIGNIFICANT DRY AIR IS WRAPPING AROUND THE WRN SIDE SUPPRESSING
CONVECTION NEAR THE WAVE. THE ONLY CONVECTION NOTED IS EMBEDDED
WITHIN THE ITCZ.

TROPICAL WAVE IS MOVING ACROSS THE ERN CARIBBEAN FROM 22N66W
ACROSS THE MONA PASSAGE TO NRN VENEZUELA NEAR 9N69W. 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 ERN CARIBBEAN EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY. NUMEROUS MODERATE/SCATTERED STRONG
CONVECTION IS IMPACTING MUCH OF THE AREA FROM 13N-18N BETWEEN
64W-68W...AND FROM 15N-23N BETWEEN 66W-70W IMPACTING AREAS OF
PUERTO RICO AND HISPANIOLA. SCATTERED MODERATE CONVECTION IS
ALSO FROM 13N-18N BETWEEN 71W-74W. THIS LARGE AREA ACTIVITY IS
ALSO ENHANCED BY DIFFLUENCE ALOFT AROUND THE ERN SIDE OF AN
UPPER LEVEL TROUGH EXTENDING FROM HAITI TO NRN COLOMBIA.

TROPICAL WAVE IS APPROACHING THE YUCATAN PENINSULA EXTENDING
FROM S OF WRN CUBA NEAR 21N85W ACROSS HONDURAS INTO THE E
PACIFIC NEAR 8N89W MOVING W 10-15 KT. THE WAVE LIES EMBEDDED
WITH AN AREA OF MODERATE DEEP LAYER MOISTURE COVERING THE W ATLC
WITH A STRONGER MAXIMUM IN THE E PACIFIC INDICATED BY TOTAL
PRECIPITABLE WATER IMAGERY. THE WAVE IS ALSO COLLOCATED WITH AN
UPPER LEVEL TROUGH PROVIDING DIFFLUENCE E OF THE WAVE AXIS WHERE
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-18N
BETWEEN 82W-85W. SIMILAR ACTIVITY IS ALSO NEAR THE NRN EXTENT OF
THE WAVE ACROSS WRN CUBA FROM 21N-23N BETWEEN 82W-85W...AS WELL
AS ACROSS THE YUCATAN PENINSULA FROM 16N-19N BETWEEN 87W-90W.

...THE ITCZ...

ITCZ AXIS IS CENTERED FROM SIERRA LEONE NEAR 9N12W ALONG 12N24W
10N37W 6N51W 9N61W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 6N-13N BETWEEN 12W-22W. SIMILAR ACTIVITY IS
WITHIN 150 NM S OF THE AXIS...AND 120 NM N OF THE AXIS BETWEEN
26W-45W...AND ALONG THE AXIS BETWEEN 54W-61W.

...DISCUSSION...

THE GULF OF MEXICO...
A 1009 MB LOW...REMNANT OF TROPICAL DEPRESSION FIVE...HAS NOW
MOVED INLAND...AND IS CENTERED OVER SE LOUISIANA NEAR 31N90W. A
SURFACE TROUGH EXTENDS FROM THE LOW CENTER TOWARDS THE WSW ALONG
29N90W 28N93W TO SRN TEXAS NEAR 27N98W. ISOLATED
SHOWERS/THUNDERSTORMS ARE WITHIN 150 NM OF THE LOW CENTER IN THE
NE AND SE QUADRANTS...AND WITHIN 100 NM OF THE CENTER IN THE SW
AND NW QUADRANTS. NUMEROUS SHOWERS/SCATTERED THUNDERSTORMS ARE
NEAR THE TROUGH AXIS S OF WRN LOUISIANA FROM 28N-30N BETWEEN
91W-94W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75
NM ELSEWHERE ALONG THE TROUGH. A WEAK SURFACE TROUGH IN THE SW
GULF LINES THE ERN COAST OF MEXICO ALONG 24N97W TO 19N95W
SUPPORTING ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ACROSS THE
WRN BAY OF CAMPECHE. THE REMAINDER OF THE BASIN IS EXPERIENCING
GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF AN UPPER LEVEL
RIDGE COVERING THE AREA CENTERED OVER CENTRAL TEXAS. EXPECT
CONTINUED SHOWER ACTIVITY ACROSS THE NRN GULF DURING THE NEXT 24
HRS.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS IMPACTING THE WRN CARIBBEAN EXTENDING FROM
WRN CUBA ACROSS HONDURAS INTO THE E PACIFIC. SCATTERED
SHOWERS/THUNDERSTORMS ARE ACROSS WRN CUBA AND THE ERN YUCATAN
PENINSULA ASSOCIATED WITH THE WAVE. SCATTERED
SHOWERS/THUNDERSTORMS ARE ALSO ACROSS NICARAGUA/ERN HONDURAS TO
THE E SIDE OF THE WAVE AXIS INFLUENCED BY DIFFLUENCE ALOFT
AROUND AN UPPER LEVEL TROUGH SITTING DIRECTLY ABOVE THE WAVE
AXIS. SHOWERS/THUNDERSTORMS ARE ALSO W OF NRN COLOMBIA DUE TO
SURFACE CONVERGENCE NEAR A PORTION OF THE ITCZ EXTENDING ACROSS
COSTA RICA ALONG 10N. A SECOND TROPICAL WAVE IS AFFECTING THE
ERN CARIBBEAN EXTENDING ACROSS THE MONA PASSAGE TO NRN
VENEZUELA. NUMEROUS SHOWERS/THUNDERSTORMS ARE NEAR THE WAVE AXIS
ALREADY IMPACTING PUERTO RICO AND HISPANIOLA. AN UPPER LEVEL
TROUGH W OF THE WAVE AXIS IS FURTHER SUPPORTING THE SHOWER
ACTIVITY NEAR THE WAVE. THE REMAINDER OF THE BASIN BETWEEN THE
TWO TROPICAL WAVES...AND ACROSS THE LESSER ANTILLES IS UNDER
MOSTLY FAIR CONDITIONS WITH MODERATELY DRY AIR ALOFT. EXPECT
CONTINUED SHOWER ACTIVITY NEAR THE TROPICAL WAVES AS THEY
PROGRESS WWD.

THE ATLANTIC OCEAN...
A WEAK SURFACE TROUGH...REMNANTS OF A FRONTAL BOUNDARY...REMAINS
IN THE W ATLC ALONG 32N65W 29N69W 30N75W 28N78W. ISOLATED
SHOWERS/THUNDERSTORMS ARE WITHIN 60 NM EITHER SIDE OF THE TROUGH
AXIS. ALOFT...AN UPPER LEVEL RIDGE BUILDS ACROSS THE AREA FROM
THE W ACCOMPANIED BY DRY AIR ALOFT KEEPING CONDITIONS FAIR
ACROSS THE REMAINDER OF THE W ATLC. HOWEVER...A TROPICAL WAVE
MOVING ACROSS THE ERN CARIBBEAN IS SUPPORTING
SHOWERS/THUNDERSTORMS N OF HISPANIOLA FROM 19N-23N BETWEEN
66W-71W. THIS ACTIVITY MAY BEGIN AFFECTING THE SE BAHAMAS OVER
THE NEXT SEVERAL HOURS. FARTHER E...SURFACE RIDING DOMINATES
ANCHORED BY A 1031 MB AZORES HIGH NEAR 41N27W MAINTAINING FAIR
WEATHER. SATELLITE IMAGERY ALSO INDICATES AN AREA OF AFRICAN
DUST ACROSS THE CENTRAL ATLC BETWEEN 50W-65W PROVIDING STABLE
CONDITIONS. ALOFT...AN UPPER LEVEL CYCLONE IS CENTERED E OF
LESSER ANTILLES NEAR 19N52W. AN UPPER LEVEL RIDGE IS COVERING
THE FAR E ATLC CENTERED NEAR 26N28W.

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

$$
WALTON/HOLLEY





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