[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010545
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT SEP 1 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION SIX IS CENTERED NEAR 12.0N 59.9W AT 01/0300
UTC OR ABOUT 85 MILES SOUTH-SOUTHWEST OF BARBADOS AND ABOUT 120
MILES EAST OF GRENADA MOVING WESTWARD AT 13 KT. MEASURED
MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND
SPEED IS 30 KT WITH GUSTS OF 40 KT. SEE LATEST NHC INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC
AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. DATA FROM THE AIRCRAFT
ALONG WITH QUIKSCAT DATA AND SUBSEQUENT SATELLITE INTENSITY
ESTIMATES SHOW THAT THE DEPRESSION IS JUST BELOW TROPICAL STORM
STRENGTH...AND IT COULD BECOME A TROPICAL STORM AT ANY TIME AS
IT MOVES THROUGH THE WINDWARD ISLANDS. MODERATE TO STRONG
CONVECTION CONVECTION IS WIDESPREAD ASSOCIATED WITH TD SIX FROM
10-14N BETWEEN 59-62W...MAINLY WEST OF THE CYCLONE.

...TROPICAL WAVES...
TROPICAL WAVE IS TILTED ALONG 20N31W 9N36W MOVING W AT ABOUT
12 KT WITH A 1010 MB LOW ALONG THE WAVE NEAR 14N.  THE WAVE AND
LOW ARE EMBEDDED WITHIN A WELL ESTABLISHED MONSOON TROUGH THAT
IS PRESENT WITH WEST TO SOUTHWEST WINDS AT THE SURFACE AND 850
MB FROM WEST AFRICA OUT TO 40W BETWEEN 5 AND 15N. A CLUSTER OF
MODERATE CONVECTION IS WITHIN 150 NM WEST OF THE LOW CENTER.

A TROPICAL WAVE IS INTRODUCED ALONG 72W ON THE 00Z SURFACE MAP
BASED ON SATELLITE IMAGERY...SFC OBSERVATIONS AND THE SSMI/AMSRE
DERIVED TOTAL PRECIPITABLE WATER. THE CIMSS VORTICITY PRODUCT
AND THE GFS ALSO INDICATE THE PRESENCE OF THIS FEATURE.
THE WAVE COUPLED WITH THE ITCZ IS GENERATING SCATTERED MODERATE
CONVECTION OVER WESTERN VENEZUELA AND NORTHERN COLOMBIA...AND IS
ALSO HELPING TO INDUCE ISOLATED TO SCATTERED SHOWERS OVER
HISPANIOLA.

TROPICAL WAVE IS ALONG 81W/82W S OF 21N MOVING W NEAR 10 KT. THE
WAVE IS DIFFICULT TO DISCERN FROM SATELLITE IMAGERY THOUGH THERE
MAY STILL EXIST A WEAK SURFACE LOW NEAR 12N81W. THE ONLY
SIGNIFICANT CONVECTION OCCURRING IN THE VICINITY OF THE WAVE IS
OVER LAND IN PANAMA...COSTA RICA AND CUBA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N16W 14N28W 14N32W 9N40W 10N50W
11N58W. IN ADDITION TO SHOWERS/CONVECTION ASSOCIATED WITH THE
TROPICAL WAVE...CLUSTERS OF SCATTERED MODERATE CONVECTION ARE
ALONG THE COAST OF SW AFRICA FROM 8-15N WEST OF 19W. WIDELY
SCATTERED SHOWERS ARE FROM 5N-10N BETWEEN 41W-55W.

DISCUSSION...
GULF OF MEXICO...
WEAK PRESSURE GRADIENT DOMINATES THE AREA WITH MAINLY LIGHT AND
VARIABLE WINDS. A WEAK SURFACE TROUGH CONTINUES OVER THE SW GULF
VERY CLOSE THE MEXICAN COAST ALONG 24N97W 20N96W AND 18N94W.
WIDELY SCATTERED MODERATE CONVECTION IS OCCURRING FROM 20-23N
WEST OF 94W. A WEAK 1011 MB LOW IS CENTERED OVER N FLORIDA NEAR
30N84W. A SURFACE TROUGH EXTENDS MAINLY SOUTH TO 26N85W.
ISOLATED SHOWERS ARE ASSOCIATED WITH THE TROUGH OVER THE NE
CORNER OF THE GULF. A WEAK HIGH PRESSURE CENTER OF 1014 MB IS AT
27N92W. ALOFT...A RIDGE IS OVER MEXICO AND THE W GULF W OF 93W.
A TROUGH IS OVER THE CENTRAL GULF 88W-93W.  AN UPPER LEVEL RIDGE
DOMINATES FLORIDA AND THE EASTERN GULF TO 88W. EXPECT CONVECTION
OVER MOST OF THE GULF ESPECIALLY OVER THE SW PORTION INCLUDING
THE BAY OF CAMPECHE...AND OVER THE NE GULF AND FLORIDA...DURING
THE NEXT 24 HOURS.

CARIBBEAN SEA...
ATTENTION REMAINS FOCUSED ON TROPICAL DEPRESSION SIX APPROACHING
THE WINDWARD ISLANDS JUST BELOW TROPICAL STORM STRENGTH. WATCHES
AND WARNINGS HAVE BEEN ISSUED. IT IS EXPECTED TO PRODUCE TOTAL
RAIN ACCUMULATIONS OF 2 TO 5 INCHES ACROSS THE WINDWARD
ISLANDS...WITH MAXIMUM AMOUNTS TO 7 INCHES. 1 TO 3 INCHES OF
RAIN ARE EXPECTED ACROSS TRINIDAD AND TOBAGO...COASTAL VENEZUELA
AND THE OFFSHORE ISLANDS...AND THE NETHERLAND ANTILLES OF
ARUBA...BONAIRE...AND CURACAO. A PAIR OF TROPICAL WAVES ARE
MOVING WWD ACROSS THE BASIN. SEE ABOVE. TRADEWINDS ARE MOSTLY
10-15 KT. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER
CENTRAL AMERICA W OF 85W.  AN UPPER LEVEL LOW IS OVER THE SW
CARIBBEAN NEAR 12N81W...THOUGH IT MAY BE RESPONSIBLE FOR THE
CENTRAL CARIBBEAN CONVECTION. A WEAK RIDGE ANCHORED ON A HIGH
OVER THE NE CARIBBEAN COVERS THE REMAINDER OF THE AREA. EXPECT
THE HIGHEST POTENTIAL FOR CONVECTION TO BE NEAR THE TROPICAL
WAVE AND CURRENTLY TROPICAL DEPRESSION SIX DURING THE NEXT 24
HOURS.

ATLANTIC OCEAN...
AS OF 03Z...A SURFACE TROUGH ENTERS THE AREA NEAR 31N72W THEN
CONTINUES WSW TO 29N78W. SCATTERED MODERATE CONVECTION IS E OF
THE TROUGH AXIS FROM 26N-31N BETWEEN 65W-73W. A DISSIPATING
STATIONARY FRONT CLIPS THE CENTRAL ATLANTIC ALONG 31N42W TO
30N50W WITH A NARROW LINE OF SHOWERS. A SURFACE RIDGE DOMINATES
MOST OF THE FORECAST AREA WEST OF 70W WITH MODERATE TRADE WINDS.
ALOFT...AN UPPER LEVEL HIGH IS CENTERED OVER THE WESTERN
ATLANTIC NEAR 27N67W. AN UPPER TROUGH OVER THE CENTRAL ATLC N OF
AREA SUPPORTS THE ABOVE MENTIONED STATIONARY FRONT. AN UPPER
LEVEL RIDGE COVERS THE CENTRAL-EASTERN ATLANTIC E OF 45W
ANCHORED ON A HIGH NEAR 22N30W.

$$
GR




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