[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 220007
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON AUG 21 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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.

...SPECIAL FEATURE...
TROPICAL DEPRESSION FOUR IS CENTERED NEAR 12.0N 22.6W 0R ABOUT
210 MILES SOUTH SOUTHEAST OF THE SOUTHERN MOST CAPE VERDE
ISLANDS AT 22/0000 UTC MOVING WEST AT 13 KT.  ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1007 MB.  MAXIMUM SUSTAINED WIND SPEED IS 30
KT WITH GUSTS TO 40 KT.  SEE LATEST NHC FORECAST/ADVISORY UNDER
HEADERS MIATCMAT4/WTNT24 NHC AND THE PUBLIC ADVISORY UNDER
HEADERS MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS.  SATELLITE
IMAGERY SHOWS WIDELY SCATTERED MODERATE CONVECTION NEAR THE
CENTER FROM 10N-14N BETWEEN 21W-25W.  A BAND OF SCATTERED
MODERATE TO STRONG CONVECTION IS S OF THE CENTER FROM 7N-10N
BETWEEN 21W-26W.  A LARGE AREA OF DUST IS N AND W OF THE T.D...
THAT USUALLY HAMPERS DEVELOPMENT.  IT IS DIFFICULT TO DETERMINE
HOW MUCH OF A FACTOR IT WILL BE.

...TROPICAL WAVES...

TROPICAL WAVE IN THE E ATLC IS ALONG 43W S OF 19N MOVING W NEAR
20 KT. A 1011 MB LOW IS PLACED ON THE WAVE AXIS NEAR 10N.  THIS
SFC LOW IS VERY BROAD...BUT SFC OBS AND A QUIKSCAT PASS HAS
HELPED LOCATE THE LOW CENTER. THE WAVE ITSELF IS ALSO
BROAD...BUT IS HIGH AMPLITUDE WITH CYCLONIC TURNING COVERING A
LARGE AREA ABOUT THE AXIS.  AGAIN SAHARAN DUST SURROUNDS THE NRN
EXTENSION OF THE WAVE.  WIDELY SCATTERED MODERATE CONVECTION IS
E OF THE WAVE AXIS FROM 10N-13N BETWEEN 38W-40W.  SIMILAR
CONVECTION IS W OF THE WAVE AXIS FROM 6N-10N BETWEEN 43W-46W.

TROPICAL WAVE IS ABOUT 230 NM E OF BARBADOS ALONG 56W S OF 19N
MOVING W 15-20 KT.  WELL DEFINED WAVE STRUCTURE WITH AN INVERTED
V-SHAPE IS EVIDENT ON SATELLITE IMAGERY. THIS WAVE ALSO APPEARS
TO BE THE LEADING EDGE OF THE SAHARAN DUST.  CONVECTION IS
MOSTLY CONFINED TO THE ITCZ.  SCATTERED MODERATE CONVECTION IS
FROM 8N-11N BETWEEN 52W-56W.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ALONG 72W/73W S OF 18N
MOVING W NEAR 15 KT.  SCATTERED MODERATE CONVECTION IS OVER
INLAND HISPANIOLA FROM 18N-20N BETWEEN 69W-73W.  SIMILAR
CONVECTION IS INLAND OVER NW VENEZUELA AND N COLOMBIA FROM
8N-11N BETWEEN 72W-75W.

TROPICAL WAVE OVER CENTRAL AMERICA IS ALONG 88W S OF 18N MOVING
W 10-15 KT.  SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
INLAND OVER THE YUCATAN PENINSULA FROM 16N-21N BETWEEN 87W-92W.
SIMILAR CONVECTION IS OVER NICARAGUA AND HONDURAS FROM 12N-16N
BETWEEN 82W-87W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N17W 10N27W 11N35W 9N45W 10N56W
9N60W.  BESIDES CONVECTION MENTIONED IN THE SPECIAL FEATURE AND
THE TROPICAL WAVES SECTIONS... SCATTERED MODERATE CONVECTION IS
FROM 7N-10N BETWEEN 46W-50W.

...DISCUSSION...
GULF OF MEXICO...
A SURFACE TROUGH IS OVER THE W GULF OF MEXICO ALONG 24N93W
19N94W.  SCATTERED SHOWERS ARE FROM 20N-26N BETWEEN 90W-97W.
SCATTERED MODERATE CONVECTION IS INLAND OVER CENTRAL FLORIDA
FROM 26N-29N BETWEEN 80W-83W.  SIMILAR CONVECTION IS INLAND FROM
S LOUISIANA TO THE FLORIDA PANHANDLE FROM 30N-32N BETWEEN
84W-92W.  IN THE UPPER LEVELS... AN UPPER LOW IS SPINNING IN THE
SW GULF NEAR 22N95W.  ANOTHER SMALL UPPER LOW IS OVER N FLORIDA
NEAR 29N83W. CONSIDERABLE CLOUDINESS COVERS THE GULF OF MEXICO.
LITTLE CHANGE IN THE WEATHER PATTERN IS EXPECTED OVER THE NEXT
24 HOURS.

CARIBBEAN SEA...
TWO TROPICAL WAVES ARE OVER THE CARIBBEAN AREA WITH ANOTHER
APPROACHING.  REFER TO THE TROPICAL WAVE SECTION ABOVE.  IN
ADDITION... SCATTERED MODERATE CONVECTION IS OVER CUBA AND THE
NW CARIBBEAN FROM 18N-22N BETWEEN 74W-85W.  FURTHER S...AN
ACTIVE ITCZ WITH WIDELY SCATTERED MODERATE CONVECTION IS INLAND
OVER SOUTH AMERICA ALONG 8N.  IN THE UPPER LEVELS... AN UPPER
LEVEL HIGH IS CENTERED NEAR JAMAICA AT 19N79W INFLUENCING THE
CONVECTION OVER CUBA.  ELY UPPER LEVEL FLOW IS OVER THE E
CARIBBEAN E OF 70W.  EXPECT THE TROPICAL WAVES TO MOVE W WITH
CONVECTION DURING THE NEXT 24 HOURS.  ALSO EXPECT THE ITCZ TO
REMAIN ACTIVE.

ATLANTIC OCEAN...
A 1028 MB HIGH DOMINATES THE ATLANTIC NEAR 37N44W.  A SMALL
SURFACE TROUGH IS NE OF THE BAHAMAS HOWEVER...ALONG 28N65W
24N70W.  SCATTERED MODERATE CONVECTION IS FROM 26N-28N BETWEEN
64W-67W.  IN THE UPPER LEVELS... SEVERAL UPPER LEVEL LOWS ARE
SEEN SPINNING IN WATER VAPOR IMAGERY ACROSS THE WRN AND CNTRL
ATLC. THE WRN-MOST IS OVER N FLORIDA NEAR 29N83W.  UPPER
DIFFLUENCE ON THE S SIDE OF THE LOW IS PRODUCING SCATTERED
SHOWERS AND TSTMS ACROSS THE BAHAMAS AND CENTRAL FLORIDA.
ANOTHER UPPER LOW IS SE OF BERMUDA NEAR 30N61W.  DIFFLUENT FLOW
ON THE S AND E SIDE OF THE CIRCULATION IS PRODUCING PATCHES OF
SHOWERS AND TSTMS.  ANOTHER UPPER LOW IS NEAR 22N43W. THIS
FEATURE IS EMBEDDED IN DRY AIR PRODUCING LITTLE WEATHER.  THE E
ATLC IS DOMINATED BY AN UPPER RIDGE WITH A HIGH CENTER NEAR
16N39W...THE RIDGE AXIS STRETCHES NE TO BEYOND 32N17W. DRY
STABLE UPPER LEVEL AIR COVERS THE AREA UNDER THIS RIDGE. IN
ADDITION TO THE DRY UPPER LEVEL AIR...WIDESPREAD SAHARAN DUST IN
THE MID-LEVELS HAS SURGED OUT TO NEAR 60W BETWEEN 11N-25N.

$$
FORMOSA





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