[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 072348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT OCT 07 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.

...TROPICAL WAVES...
A HIGH AMPLITUDE TROPICAL WAVE IS ALONG 40W S OF 21N MOVING W
ABOUT 15 KT. THE WAVE AXIS IS EASILY IDENTIFIABLE ON SATELLITE
IMAGERY WITH A LARGE INVERTED-V SIGNATURE NOTED. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS EMBEDDED IN THE ITCZ
WITHIN SEVERAL HUNDRED NM OF THE WAVE AXIS. ISOLATED TO
SCATTERED SHOWERS ARE ALONG THE WAVE AXIS...WITH A SWIRL OF LOW
CLOUDS NEAR 13N.

A TROPICAL WAVE IS ALONG 58W S OF 16N MOVING W NEAR 15 KT. THIS
WAVE HAS LITTLE SIGNATURE ASSOCIATED WITH IT. SOME SLIGHT LOW TO
MID LEVEL CYCLONIC TURNING IS LOCATED E OF THE AXIS. SCATTERED
SHOWERS AND TSTMS ARE FROM 10N-13N BETWEEN 50W-60W.

A TROPICAL WAVE IS IN THE ERN CARIBBEAN ALONG 67 S OF 17N MOVING
W 10 TO 15 KT. A WEAK INVERTED V PATTERN IS NOTED ON VIS IMAGES.
WESTERLY UPPER LEVEL FLOW IS SHEARING SCATTERED SHOWERS AND
TSTMS TO THE WINDWARD ISLANDS.

A TROPICAL WAVE IS OVER THE YUCATAN PENINSULA AND GUATEMALA INTO
THE EPAC MOVING W 10 TO 15 KT. CLUSTERS OF SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION ARE OVER THE YUCATAN PENINSULA...
BELIZE...GUATEMALA AND EL SALVADOR. SIMILAR CONVECTION IS ALSO
FOUND OVER THE CARIBBEAN PLAINS OF NICARAGUA...NE HONDURAS AND
ADJACENT COASTAL WATERS FROM 12N-17N BETWEEN 80W-85W.
A DIFFLUENT PATTERN ALOFT BETWEEN A LARGE TROUGH IN THE E GULF
AND A RIDGE IN THE SRN CARIBBEAN IS ENHANCED THIS CONVECTIVE
ACTIVITY.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N15W 7N30W 9N38W 6N50W 7N57W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-10N
BETWEEN 27W-37W. SIMILAR CONVECTION IS SEEN FROM 6N-9N BETWEEN
43W-49W.

...DISCUSSION...
THE GULF OF MEXICO...
A LARGE CUT OFF LOW LOCATED OVER THE CAROLINAS COVERS THE SE
U.S....INCLUDING THE STATE OF FLORIDA AND THE EASTERN PORTION OF
THE GULF. STRONG SUBSIDENCE ACCOMPANIES THIS FEATURE WITH VERY
DRY AIR ALOFT NOTED ON WATER VAPOR IMAGES E OF 90W N OF 24N. A
NARROW RIDGE EXTENDS MAINLY NORTH FROM THE YUCATAN PENINSULA AND
THE BAY OF CAMPECHE TO EASTERN TEXAS. A FAIR AMOUNT OF MOISTURE
IS IN THE WRN GULF AHEAD OF AN UPPER TROUGH THAT LIES ALONG THE
MEXICAN GULF COAST. THIS MOISTURE IS BEING ADVECTED EASTWARD
ACROSS THE SRN GULF AND NRN CARIBBEAN BY A WESTERLY JET WITH
CORE WINDS OF 60-70 KT BASED ON UW-CIMSS DERIVED UPPER LEVEL
WINDS. AT THE SURFACE...A TROUGH PERSIST OVER THE WESTERN GULF
ALONG 26N94W 20N92W. SHOWERS AND THUNDERSTORMS OVER THIS AREA
HAVE DIMINISHED AND FURTHER DEVELOPMENT IS NOT EXPECTED. A WEAK
COLD FRONT IS IN THE NRN GULF STRETCHING FROM CENTRAL FLORIDA TO
28N84W...THEN CONTINUES MAINLY WWD AS A STATIONARY FRONT TO
27N94W. ONLY A NARROW BAND OF LOW CLOUDS REPRESENT THIS FRONTAL
BOUNDARY. THE FRONTAL SYSTEM AND THE SURFACE TROUGH WILL
DISSIPATE ON SUNDAY.

THE CARIBBEAN SEA...
THE MOST ACTIVE WEATHER IN THE CARIBBEAN SEA IS FOUND WEST OF
80W...WHERE SCATTERED MODERATE CONVECTION EXISTS FROM 11N-17N
BETWEEN 80W-85W. THIS ACTIVITY IS ENHANCED BY UPPER DIFFLUENCE.
CLUSTERS OF MODERATE CONVECTION ARE AFFECTING COSTA RICA AND
PARTS OF PANAMA ASSOCIATED WITH THE ITCZ.  A WEAK UPPER TROUGH
IS OVER THE EASTERN CARIBBEAN AND EXTENDS FROM THE LEEWARD
ISLANDS TO NORTH CENTRAL VENEZUELA. DRY AIR COVERS THE AREA EAST
OF 72W. MODERATE TO STRONG ELY TRADE WINDS ARE BLOWING ACROSS
THE BASIN WITH THE STRONGEST WINDS OF 20-25 KT OVER THE
SOUTH CENTRAL CARIBBEAN. LITTLE CHANGE IN THESE WINDS ARE
EXPECTED OVER THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE ATLANTIC OCEAN. A
DEEP LAYERED TROUGH COVERS MUCH OF THE EASTERN U.S. AND WRN ATLC
W OF 70W N OF 24N. DRY AIR RESULTING IN MODERATE TO STRONG
SUBSIDENCE IS ASSOCIATED WITH THE TROUGH. THE ATTENDANT COLD
FRONT ENTERS THE AREA NEAR 31N77W...THEN CONTINUES SW ACROSS
CENTRAL FLORIDA AND THE EASTERN GULF. A MID-UPPER LEVEL
ANTICYCLONE CENTER NEAR 30N54W LIES TO THE E OF THE TROUGH AND
COVERS THE REGION BETWEEN 42W AND 63W. DRY STABLE AIR IS ALSO IN
PLACE UNDERNEATH THE RIDGE LIMITING ANY SHOWER ACTIVITY. A SWLY
WIND FLOW EXISTS BETWEEN THESE FEATURES AND IS ADVECTING A SWATH
OF MOISTURE BETWEEN 63W AND 70W. A 1008 MB SFC LOW IS LOCATED
NORTH OF THE AREA NEAR 35N65W WITH A SFC TROUGH EXTENDING SWD
FROM THE LOW TO THE ERN BAHAMAS. THIS LOW HAS NOT SHOWN ANY
SIGNS OF ACQUIRING SUBTROPICAL CHARACTERISTICS...AND IS EXPECTED
TO MERGE WITH A NEARBY FRONTAL BOUNDARY DURING THE NEXT 24 HOURS
AS IT QUICKLY MOVES TO THE NE. IN THE EASTERN ATLC...AN
ELONGATED UPPER TROUGH RUNS FROM JUST E OF THE AZORES ALONG
29N31W 23N40W 20N50W WITH A COUPLE EMBEDDED UPPER LOW
CENTERS....ESPECIALLY IN THE WESTERN PORTION OF THE TROUGH AXIS.
AT THE SURFACE...A BROAD RIDGE DOMINATES THE ATLC EAST OF 65W
WITH A 1025 MB HIGH LOCATED NEAR 32N50W. ORGANIZED SHOWERS AND
TSTMS IN THE CNTRL AND ERN ATLC ARE CONFINED TO THE ITCZ AND
TROPICAL WAVES.

$$
GR





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