[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011737
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU SEP 01 2011

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURE...
HURRICANE KATIA IS CENTERED NEAR 15.3N 47.5W AS OF 01/1500 UTC
OR ABOUT 915 NM KM E OF THE NORTHERN LEEWARD ISLANDS MOVING W AT
16 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB. MAXIMUM
SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. PLEASE SEE
THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER
MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADER MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE AREA
FROM 14N-18N BETWEEN 45W-49W WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 11N-20N BETWEEN 41W-53W.

TROPICAL WAVE OVER THE GULF OF MEXICO AT 01/1500 UTC EXTENDS
FROM 28N90W TO INLAND OVER S MEXICO NEAR CIUDAD DEL CAMPECHE TO
17N92W. SCATTERED/HEAVY SHOWERS WITH EMBEDDED CLUSTERS OF
THUNDERSTORMS COVERS THE E GULF E OF 90W. UPPER LEVEL WINDS ARE
FORECAST TO BECOME MORE CONDUCIVE FOR DEVELOPMENT AND THIS
SYSTEM COULD BECOME A TROPICAL DEPRESSION DURING THE NEXT DAY OR
SO. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AS IT MOVES SLOWLY NORTHWESTWARD.
INTERESTS ALONG THE ENTIRE NORTHERN GULF OF MEXICO COAST SHOULD
MONITOR THE PROGRESS OF THIS DISTURBANCE.

THE LOW PRESSURE SYSTEM LOCATED ABOUT 315 NM N OF BERMUDA NEAR
37N64W APPEARS TO BE ACQUIRING SOME TROPICAL CHARACTERISTICS BUT
HAS CHANGED LITTLE OVER THE PAST FEW HOURS. THIS SYSTEM IS
PRODUCING WINDS OF TROPICAL STORM FORCE AND ONLY A SLIGHT
INCREASE IN ORGANIZATION COULD RESULT IN THE FORMATION OF A
TROPICAL STORM. THE LOW IS MOVING LITTLE AT THIS TIME BUT SHOULD
BEGIN TO MOVE NORTHEASTWARD TONIGHT. THIS SYSTEM HAS A MEDIUM
CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
PLEASE SEE THE HIGH SEAS FORECAST UNDER AWIPS/WMO HEADER
NFDHSFAT1/FZNT01 KWBC FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE WAS INTRODUCED IN THE E TROPICAL ATLC EXTENDING
FROM THE CAPE VERDE ISLANDS NEAR 16N23W THROUGH A PREVIOUSLY
ANALYZED SURFACE LOW NEAR 11N23W...NOW A 1012 MB LOW NEAR
10N25W...TO 7N26W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE WITHIN 120/150 NM OF LINE FROM 15N24W TO
8N29W.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA AND DOES NOT ENTER
THE E TROPICAL ATLC REGION. CLUSTERS OF SCATTERED MODERATE TO
SCATTERED STRONG CONVECTION DOT THE TROPICS WITHIN 150 NM OF
LINE FROM THE COAST OF SW AFRICA NEAR 8N13W TO 5N31W.

...DISCUSSION...

GULF OF MEXICO...
A TROPICAL WAVE IS OF INTEREST IN THE GULF THIS AFTERNOON...SEE
SPECIAL FEATURES SECTION ABOVE. AN ABUNDANCE OF DEEP LAYER
MOISTURE COVERS THE GULF. A SHORTWAVE UPPER TROUGH EXTENDS FROM
MOBILE ALABAMA THROUGH AN UPPER LOW NEAR 30N91W TO THE COAST OF
TEXAS NEAR HOUSTON GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS N OF 28N E OF 90W. AN UPPER RIDGE DOMINATES MOST
OF THE GULF ANCHORED INLAND OVER S/CENTRAL TEXAS EXTENDING AN
AXIS ROUGHLY E ALONG 25N TO ACROSS S FLORIDA. CLUSTERS OF
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE OVER
THE W GULF S OF 26N W OF 90W. THE TROPICAL WAVE WILL MOVE SLOWLY
W THROUGH SAT. A LOW PRESSURE WILL LIKELY FORM ALONG THE N
PORTION OF THE WAVE LATER THIS AFTERNOON THEN WILL SLOWLY MOVE
NW TOWARDS THE NW GULF THROUGH FRI...POSSIBLY AS A TROPICAL
CYCLONE.

CARIBBEAN SEA...
AN ABUNDANCE OF DEEP LAYER MOISTURE COVERS THE NW CARIBBEAN
WHERE AN UPPER RIDGE EXTENDING ACROSS THE GULF OF MEXICO IS
GIVING THE NW CARIBBEAN NE FLOW ALOFT. AN INVERTED UPPER TROUGH
EXTENDS ACROSS THE CENTRAL CARIBBEAN FROM COSTA RICA TO E CUBA
NEAR 20N76W ENHANCING THE NE FLOW OVER THE NW CARIBBEAN AND THE
SCATTERED SHOWERS/THUNDERSTORMS N OF 19N W OF 84W. THE MONSOON
TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 11N74W
TO ACROSS NICARAGUA INTO THE E PACIFIC REGION NEAR 12N84W AND
GENERATING SCATTERED/HEAVY SHOWERS WITH EMBEDDED THUNDERSTORMS S
OF 14N W OF 80W TO INLAND OVER CENTRAL AMERICA. THE REMAINDER OF
THE CARIBBEAN IS UNDER MOSTLY CLEAR SKIES THIS AFTERNOON. HIGH
PRESSURE OVER THE CAROLINAS WILL WEAKEN AS HURRICANE KATIA MOVES
THROUGH THE ATLC ALLOWING TRADE WINDS TO DIMINISH OVER THE
CARIBBEAN THIS WEEKEND.

ATLANTIC OCEAN...
TROPICAL STORM KATIA REMAINS IN THE CENTRAL TROPICAL ATLC...SEE
SPECIAL FEATURES SECTION ABOVE. AN UPPER TROUGH EXTENDS OVER THE
W ATLC N OF 26N W OF 65W SUPPORTING SURFACE FEATURES N OF THE
DISCUSSION AREA AND A SURFACE TROUGH THAT EXTENDS FROM 31N67W TO
25N72W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 180 NM E OF THE SURFACE TROUGH AND ISOLATED SHOWERS/
THUNDERSTORMS WITHIN 90/120 NM OF 27N W OF 69W TO INLAND OVER
THE FLORIDA PENINSULA. A BROAD UPPER TROUGH COVERS THE CENTRAL
ATLC WITH THE AXIS EXTENDING FROM BEYOND 32N55W THROUGH AN UPPER
LOW NEAR 27N55W TO THE TROPICS NEAR 18N59W GENERATING CLUSTERS
OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM OF LINE
FROM 23N53W TO 30N49W AND N OF 30N BETWEEN 45W-55W. A SURFACE
RIDGE COVERS THE CENTRAL INTO THE E ATLC ANCHORED BY A 1025 MB
HIGH N OF THE DISCUSSION ABOUT 700 NM WSW OF THE AZORES. AN
UPPER TROUGH IS OVER THE E ATLC EXTENDING FROM BEYOND 32N14W
THROUGH AN UPPER LOW NEAR 25N26W TO NE OF HURRICANE KATIA NEAR
21N33W SUPPORTING A COLD FRONT THAT EXTENDS THROUGH 32N10W
ACROSS THE CANARY ISLANDS TO NEAR 28N17W WHERE IT DISSIPATES TO
27N21W. ISOLATED SHOWERS ARE WITHIN 45 NM SE OF THE COLD FRONT.
HURRICANE KATIA WILL GRADUALLY INTENSIFY AS IT MOVES INTO THE W
TROPICAL ATLC THROUGH THE WEEKEND THEN TO THE NE OF THE LEEWARD
ISLANDS. HIGH PRESSURE OVER THE CAROLINAS TO BERMUDA WILL WEAKEN
AS KATIA MOVES THROUGH THE ATLC.

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

$$
PAW





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