[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301152
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN SEP 30 2012

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
XXXX UTC.

...SPECIAL FEATURES...

HURRICANE NADINE IS LOCATED NEAR 36.6N 37.8W AT 30/0900 UTC OR
ABOUT 521 NM WSW OF THE AZORES MOVING NNW NEAR 10 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 979 MB. MAXIMUM SUSTAINED WIND SPEED
IS 80 KT WITH GUSTS TO 100 KT. PLEASE SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE
DETAILS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM
35N-39N BETWEEN 36W-41W.

...TROPICAL WAVES...

TROPICAL WAVE CONTINUES EXTENDS FROM 15N21W TO A 1012 MB LOW
NEAR 9N25W EMBEDDED WITHIN A MONSOONAL GYRE AND DEEP MOISTURE
NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. WIDELY SCATTERED
MODERATE CONVECTION IS FROM FROM 7N-15N BETWEEN 20W-32W.

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC EXTENDING
FROM 19N37W TO 10N40W MOVING W AT ABOUT 10 KT. WAVE IS ALONG THE
LEADING EDGE OF A BROAD AREA OF DEEP MOISTURE AS DEPICTED BY THE
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION
IS FROM FROM 13N-20N BETWEEN 35W-41W.

TROPICAL WAVE IS NEARLY STATIONARY OVER THE NW CARIBBEAN
EXTENDING FROM 24N79W TO 17N83W. AN UPPER LEVEL LOW SPINS OVER
THE WAVE DISPLACING THE CONVECTION TO THE E OF THE WAVE AXIS N
OF 16N BETWEEN 78W-81W...INCLUDING PORTIONS OF CUBA. THE UPPER
LOW SEEMS TO BE TAKING A MORE SIGNIFICANT ROLE IN CONTROLLING
THE TILT AND PATH OF THE WAVE. GLOBAL MODELS SUGGEST THIS WAVE
WILL BECOME ABSORBED BY THE UPPER LOW/TROUGH DURING THE NEXT
24-36 HOURS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO THE COASTAL
WATERS OF MAURITANIA NEAR 17N17W...THEN IT REDEVELOPS FROM A
BROAD GYRE CENTERED FROM A 1012 MB LOW AND ASSOCIATED TROPICAL
WAVE NEAR 9N25W ALONG 8N33W TO 9N44W...WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 7N50W TO THE COAST OF GUYANA NEAR 8N58W. A
SURFACE TROUGH IS ANALYZED FROM 15N54W TO 10N56W...JUST N OF THE
WESTERN EXTENT OF THE ITCZ AXIS. THIS TROUGH IS ENHANCED BY AN
UPPER LEVEL TROUGH NOTED ALONG 49W OVER THE TROPICAL ATLC.
SCATTERED MODERATE CONVECTION IS FROM 7N-15N BETWEEN 20W-32W.
SIMILAR CONVECTION IS ELSEWHERE WITHIN 70-140 NM ON EITHER SIDE
OF THE ITCZ AND MONSOON TROUGH.

...DISCUSSION...

GULF OF MEXICO...
MOSAIC DOPPLER RADAR IMAGERY CONTINUES TO SHOW CLUSTERS OF
SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE
NW AND N-CENTRAL WATERS W OF A LINE FROM THE FLORIDA BIG BEND TO
THE COAST OF TAMPICO MEXICO. THE ACTIVITY IS ASSOCIATED TO A
VIGOROUS UPPER LEVEL SHORTWAVE/TROUGH MOVING EASTWARD ACROSS SRN
TEXAS WITH STRONG DIFFLUENCE AHEAD OF IT...SUPPORTING A LOW
PRESSURE SYSTEM CENTERED OVER ERN TEXAS AND ASSOCIATED FRONT
EXTENDING SSW ALONG GALVESTON TO TAMPICO. EXPECT THE COLD FRONT
TO EXPAND ACROSS THE NW WATERS TODAY WITH GUSTY NW WINDS UP TO
25 KT BEHIND IT. RETURN FLOW AHEAD OF IT MAY INCREASE TO 25 KT
AS WELL. THE FRONT IS EXPECTED TO EXTEND FROM SE LOUISIANA TO
VERACRUZ MEXICO LATE SUN AND FROM FLORIDA PANHANDLE TO YUCATAN
LATE MON...BECOMING STATIONARY FROM TAMPA BAY TO YUCATAN
PENINSULA TUE THEN DISSIPATE WED. OTHERWISE...A BROAD/STRONG
UPPER RIDGE IS CENTERED OVER ERN MEXICO SPREADING MIDDLE TO
UPPER MOISTURE AND CIRRUS FROM THE CONVECTION MENTIONED ABOVE
ACROSS THE NRN HALF OF THE GULF BASIN.

CARIBBEAN SEA...
A NEARLY STNRY UPPER LOW SPINS OVER THE WRN CARIBBEAN CENTERED
NEAR 18N84W. THIS FEATURE SITS ON TOP OF A TROPICAL WAVE WHICH
SEEMS TO BE AFFECTING ITS WESTWARD TRACK. MODERATE DIFFLUENCE
ALOFT E OF THE UPPER LOW COMBINED WITH LOW LEVEL MOISTURE
CONVERGENCE RELATED TO THE TROPICAL WAVE IS GENERATING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE N OF 15N BETWEEN
72W-81W...INCLUDING THE WINDWARD PASSAGE AND INLAND PORTIONS OF
HAITI AND ERN CUBA. TO THE S OF THIS AREA OF ACTIVE WEATHER...
THE ERN PACIFIC MONSOON TROUGH CROSSES CENTRAL AMERICA ALONG
INLAND PORTIONS OF COSTA RICA AND PANAMA TO NRN COLOMBIA
GENERATING SIMILAR CONVECTION S OF 12N W OF 72W. THE REMAINDER
OF THE CARIBBEAN SEA E OF 72W IS UNDER FAIR SKIES WITH 10-20 KT
TRADE WINDS THIS MORNING. HIGH PRESSURE OVER THE CENTRAL ATLC
WILL BUILD SW ACROSS THE CARIBBEAN...INCREASING TRADE WIND FLOW
THROUGH WEDNESDAY.

ATLANTIC OCEAN...
BROAD UPPER LEVEL DIFFLUENCE COVERS A GREAT PORTION OF THE
WESTERN NORTH ATLC W OF 60W SUPPORTING A COLD FRONT N OF THE
DISCUSSION AREA...EXPECTED TO GENERATE GUSTY SOUTHERLY WINDS W
OF 75W THROUGH MONDAY NIGHT AND TUESDAY. THEN...THE WEAKENED
FRONT WILL ENTER THE FAR NW PORTION OF AREA WEDNESDAY WITH LIGHT
WINDS. THE BROAD UPPER DIFFLUENCE LIES BETWEEN AN ELONGATED
UPPER LEVEL RIDGE EXTENDING ALONG 32N62W TO 19N71W AND AN UPPER
LEVEL TROUGH MOVING OFF THE ERN CONUS SEABOARD. THE OVERALL
ACTIVITY SUPPORTS A SURFACE TROUGH ANALYZED FROM 25N69W TO
2171W. DESPITE THE LOCATION OF THE SURFACE FEATURE...NUMEROUS
SCATTERED MODERATE CONVECTION COVER AN AREA FROM 21N-28N BETWEEN
63W-70W...AS WELL AS S OF 25N BETWEEN 70W-80W INCLUDING MOST OF
THE BAHAMAS. THE REMINDER OF THE ATLC BASIN IS INFLUENCED BY
SURFACE RIDGING AROUND A 1028 MB HIGH LOCATED A FEW MILES N OF
THE AZORES.

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

$$

GARCIA




This weather bulletin was brought to you by:
www.nashvilleweather.net