[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 262339
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN AUG 26 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 32W S OF 16W MOVING W NEAR 10-15 KT.
ACCORDING TO THE UW-CIMSS TPW PRODUCT...MUCH OF THE CYCLONIC
TURNING AND HIGHEST MOISTURE CONTENT WITH THIS WAVE HAVE HAD A
SW MOTION OVER THE LAST DAY OR SO. SCATTERED MODERATE CONVECTION
IS SEEN FROM 9N-13N BETWEEN 30W-36W.

LOW AMPLITUDE TROPICAL WAVE IS ALONG 54/55W S OF 15N MOVING W 10
KT. A SWIRL OF LOW CLOUDS REMAINS ASSOCIATED WITH THE WAVE NEAR
12N55W. SHOWER AND TSTM ACTIVITY IS MINIMAL.

A NEW TROPICAL WAVE IS INTRODUCED ALONG 71W ON THE 1800 UTC
SURFACE MAP BASED ON SATELLITE IMAGERY...SFC OBSERVATIONS AND
THE CURACAO VERTICAL SOUNDING THAT SHOWED THE PASSAGE OF THE
WAVE THIS MORNING. A LARGE AREA OF DISORGANIZED SHOWERS AND
THUNDERSTORMS OVER THE CENTRAL CARIBBEAN IS ASSOCIATED WITH THIS
FEATURE. THERE ARE NO SIGNS OF A CLOSED SURFACE CIRCULATION AND
DEVELOPMENT..IF ANY...IS EXPECTED TO BE SLOW TO OCCUR AS THE
SYSTEM MOVES WESTWARD AROUND 15 TO 20 MPH. COMPUTER MODELS HAVE
MOISTURE FROM THIS WAVE REACHING THE CARIBBEAN PLAINS OF
NICARAGUA LATE MONDAY OR EARLY TUESDAY.

TROPICAL WAVE IS IN THE W CARIBBEAN AND OVER CENTRAL AMERICA
ALONG 85W S OF 23N MOVING W 10-15 KT. THIS WAVE IS ENHANCING
SOME OF THE SHOWER/TSTM ACTIVITY IN THE SE GULF...OVER WESTERN
CUBA AND ACROSS NICARAGUA AND NE HONDURAS. AN EARLIER QUIKSCAT
PASS SHOWED VERY CLEAR THE WIND SHIFT ASSOCIATED WITH THIS WAVE.
SCATTERED SHOWERS ARE OVER THE NW CARIBBEAN.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N16W 9N30W 8N40W 10N52W 9N61W.
BESIDES FOR THE CONVECTION DISCUSSED IN THE TROPICAL WAVES
SECTION...A 70 NM WIDE BAND OF SCATTERED MODERATE CONVECTION IS
S OF THE AXIS ALONG 5N-6N BETWEEN 21W-38W. CLUSTERS OF MODERATE
TO ISOLATED STRONG CONVECTION ARE OVER SENEGAL IN WESTERN
AFRICA.

DISCUSSION...

GULF OF MEXICO...
MAIN FEATURE IN THE AREA THIS EVENING IS A WEAK AREA OF LOW
PRESSURE LOCATED JUST EAST OF TAMPICO MEXICO. AS OF 21Z...THE
LOW IS LOCATED NEAR 22N97W WITH 1008 MB. THIS SYSTEM HAVE BECOME
A LITTLE BETTER ORGANIZED. HOWEVER...THIS FEATURE IS EXPECTED TO
MOVE INLAND LATER TONIGHT OR EARLY MONDAY...AND SIGNIFICANT
DEVELOPMENT IS UNLIKELY. LOCALLY HEAVY RAINFALL IS POSSIBLE OVER
CENTRAL MEXICO DURING THE NEXT DAY OR SO AS THE SYSTEM MOVES
SLOWLY WESTWARD. TAMPICO REPORTED NLY WINDS OF 22 KT AND TSRA
DURING THE LAST FEW HOURS. THE ASSOCIATED SCATTERED MODERATE
CONVECTION IS FROM 20N-26N WEST OF 90W...INCLUDING ALSO THE
EASTERN SLOPES OF THE SIERRA MADRE MOUNTAINS. A SFC TROUGH OVER
THE EASTERN GULF ALONG 85W CONTINUES TO PRODUCE SCATTERED
MODERATE CONVECTION OVER THE GULF MAINLY N OF 24N AND E OF 88W.
THIS CONVECTION IS BEING SUPPORTED BY A DIFFLUENT PATTERN ALOFT
BETWEEN AN UPPER LOW LOCATED JUST S OF LOUISIANA...RIDGING OVER
THE NE CORNER OF THE GULF AND AN INVERTED UPPER TROUGH OVER THE
FAR SE PORTION. WEAK RIDGING WILL MEANDER AROUND 30N OVER THE
NEXT COUPLE OF DAYS.

CARIBBEAN SEA...
THE MOST SIGNIFICANT AREA OF CONVECTION IS OFF THE COAST OF
COLOMBIA AND VENEZUELA ASSOCIATED WITH A TROPICAL WAVE. SEE
ABOVE. CLUSTERS OF MODERATE CONVECTION ARE ALSO OVER NORTHERN
VENEZUELA ASSOCIATED WITH A NORTHWARD MODULATION OF THE ITCZ.
AFTERNOON HEAT INDUCED SHOWERS ARE OVER PARTS OF THE GREATER
ANTILLES. ALL OF THE ACTIVITY IS ALSO BEING SUPPORTED BY
DIFFLUENCE ALOFT BETWEEN THE UPPER TROUGHING BETWEEN PANAMA AND
JAMAICA...AND ATLC RIDGING EXTENDING INTO THE ERN CARIBBEAN.
UPPER NLY WINDS ARE FOUND OVER THE WESTERN CARIBBEAN. ABUNDANT
UPPER LEVEL MOISTURE IS ACROSS THE BASIN. THE TRADE WIND FLOW IS
ON THE LIGHT TO MODERATE SIDE...AND IS ONLY EXPECTED TO INCREASE
SLIGHTLY OVER THE NEXT COUPLE OF DAYS.

ATLANTIC OCEAN...
THE SFC PATTERN ACROSS THE ATLC DISCUSSION AREA REMAINS FAIRLY
WEAK THIS EVENING. THIS WEAK PATTERN IS MAINLY DUE TO AN UNUSUAL
FRONTAL BOUNDARY DEEP INTO THE SUBTROPICS ENTERING THE AREA NEAR
32N38W TO 26N55W THEN CONTINUING WSW THEN NW AS A TROUGH THROUGH
23N63W 28N69W. ISOLATED SHOWERS AND TSTMS ARE ASSOCIATED WITH
FRONT. A WEAK 1018 MB HIGH IS OVER THE WRN ATLC NEAR 29N72W. A
SFC TROUGH IS JUST E OF THE LEEWARD ISLANDS ALONG 21N58W 15N60W
GENERATING JUST A FEW SHOWERS WITHIN 60 NM EITHER SIDE OF THE
AXIS. A WEAK RIDGE AXIS DOMINATES THE REMAINDER OF THE CENTRAL
AND E ATLC. LOOK FOR THE FRONT TO CONTINUE BECOMING DIFFUSE OVER
THE NEXT DAY OR SO. ELSEWHERE ALOFT...AN UPPER HIGH IS JUST
OFFSHORE N FLORIDA NEAR 30N80W. A TUTT LOW REMAINS NE OF PUERTO
RICO NEAR 26N57W. AN UPPER TROUGH EXTENDS SW FROM THIS LOW TO
HISPANIOLA. DIFFLUENCE AHEAD OF THIS TROUGH WAS SUPPORTING THE
DEVELOPMENT OF SHOWERS AND TSTMS OVER PUERTO RICO AND HISPANIOLA
DURING THE AFTERNOON HOURS AND EARLY THIS EVENING. ANOTHER UPPER
HIGH IS OVER THE CENTRAL ATLC NEAR 22N42W THAT IS SURROUNDED BY
DRY/STABLE AIR. THIS UPPER HIGH IS EMBEDDED IN THE LARGER SCALE
RIDGING EXTENDING E FROM WESTERN AFRICA.

$$
GR






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