[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 120005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MON 11 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
2345 UTC.

...SPECIAL FEATURES...

THE CENTER OF HURRICANE FLORENCE AT 12/0000 UTC WAS LOCATED
NEAR LATITUDE 35.2 NORTH...LONGITUDE 64.4 WEST OR ABOUT 195
MILES...315 KM...NORTH OF BERMUDA. FLORENCE IS MOVING TOWARD THE
NORTH-NORTHEAST NEAR 16 MPH...26 KM/HR. THIS GENERAL MOTION WITH
SOME INCREASE IN FORWARD SPEED IS EXPECTED DURING THE NEXT 24
HOURS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 974 MB. MAXIMUM
SUSTAINED WINDS HAVE DECREASED TO NEAR 85 MPH...140 KM/HR...WITH
HIGHER GUSTS. FLORENCE IS A CATEGORY ONE HURRICANE ON THE
SAFFIR-SIMPSON SCALE. FURTHER WEAKENING IS LIKELY OVERNIGHT.
PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC OR THE PUBLIC ADVISORY UNDER
MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. FLORENCE IS A LARGE
HURRICANE. HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 70
MILES...110 KM...FROM THE CENTER...AND TROPICAL STORM FORCE
WINDS EXTEND OUTWARD UP TO 290 MILES...465 KM. WINDS AT BERMUDA
WILL CONTINUE TO DECREASE THIS EVENING.

THE CENTER OF RECENTLY UPGRADED TROPICAL STORM GORDON AT 11/2100
UTC IS NEAR 21.6N 57.3W. THIS POSITION ALSO IS ABOUT 425
MILES/690 KM NORTHEAST OF THE LEEWARD ISLANDS. GORDON IS MOVING
TOWARD THE NORTHWEST NEAR 9 MPH...15 KM/HR...AND
THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS.THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED
WINDS ARE NEAR 45 MPH...75 KM/HR...WITH HIGHER GUSTS.
ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT 24
HOURS. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY
MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS.

A 1008 MB LOW PRESSURE CENTER NEAR 12N17W IS EMERGING OFF THE
COAST OF AFRICA. DEVELOPMENT OF THIS SYSTEM IS POSSIBLE DURING
THE NEXT DAY OR TWO AS IT MOVES WESTWARD OVER THE FAR EASTERN
TROPICAL ATLANTIC. A CLUSTER OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS SEEN FROM 7N-10N BETWEEN 16W-24W.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 31W/32W SOUTH OF 18N
MOVING WEST NEAR 10 KT. PRECIPITATION AND CLOUDINESS ASSOCIATED
WITH THIS WAVE IS MOSTLY CONFINED TO THE ITCZ...THOUGH SOME LOW
TO MID CLOUD CYCLONIC TURNING IS STILL NOTED N OF 12N. THE
PLACEMENT OF THIS WAVE (ALONG WITH THE SPECIAL FEATURE MOVING
OFF AFRICA) IS OBVIOUS AFTER VIEWING A METEOSAT8 HOVMOLLER
DIAGRAM.

A LOW AMPLITUDE ATLANTIC OCEAN TROPICAL WAVE IS ALONG 43W/44W
SOUTH OF 16N MOVING WEST NEAR 10 KT. THE PLACEMENT OF THIS WAVE
REMAINS DIFFICULT WITH CONVECTION FROM THE ITCZ...ALONG WITH MID
TO UPPER LEVEL SW FLOW...OBSCURING THE SIGNAL. SCATTERED SHOWERS
AND TSTMS FROM 7N-16N BETWEEN 40W-50W BETWEEN 1800-1900 UTC ARE
NOW BECOMING MORE ISOLATED IN NATURE.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 60W SOUTH OF 16N MOVING
WEST NEAR 15 KT. THIS WAVE SPLIT LAST EVENING WITH THE NRN
EXTENSION NOW T.S. GORDON. ISOLATED SHOWERS/TSTMS EXIST FROM
10N-14N BETWEEN 56W-63W. A FEW STRONGER CLUSTERS OF MODERATE
CONVECTION ARE MOVING W THROUGH NE VENEZUELA.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N19W 10N31W 9N34W 9N43W 10N46W
10N58W. ASIDE FROM THE WEATHER ASSOCIATED WITH THE TROPICAL
WAVES AND SPECIAL FEATURE OFF AFRICA...SCATTERED MODERATE
CONVECTION IS FROM 4N-7N BETWEEN 37W-42W. SCATTERED
SHOWERS/TSTMS ARE FROM 10N-14N BETWEEN 52W-58W.

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL HIGH IS OVER CENTRAL MEXICO NEAR 24N102W THAT HAS
RIDGING EXTENDING E TO NEAR 26N85W. UPPER DIFFLUENT AIR BETWEEN
THE FLOW AROUND THIS HIGH AND THE WESTERLIES OVER THE DEEP SOUTH
AND SE US IS HELPING TO SUPPORT THE SCATTERED SHOWERS AND TSTMS
SEEN MAINLY IN THE NRN HALF OF THE GULF FROM 25N-30N BETWEEN
83W-97W. GUIDANCE SUGGESTS THE UPPER DIFFLUENCE WILL PERSIST
OVER THIS REGION OVER THE NEXT 24HRS...SO THIS SHOULD BE ENOUGH
TO KEEP ISOLATED TO SCATTERED SHOWER/TSTMS ACTIVITY CONTINUING.
GOES HIGH DENSITY WINDS FROM 250-350MB...ALONG WITH WV
IMAGERY...REVEAL AN UPPER ANTICYCLONE OVER THE FLORIDA STRAITS
NEAR 24N81W...ALONG WITH AN UPPER TROUGH MOVING W FROM THE
YUCATAN. CLUSTERS OF SCATTERED MODERATE CONVECTION ASSOCIATED
WITH DIURNAL INFLUENCES OVER CUBA AND THE YUCATAN ARE BEGINNING
TO MOVE INTO THE FAR SE GULF AND FAR ERN BAY OF
CAMPECHE...RESPECTIVELY. AT THE SURFACE...5-15KT E/SE FLOW IS
DOMINATING AROUND THE BASE OF THE SFC HIGH BUILDING S FROM ERN
CANADA.

THE CARIBBEAN SEA...
OVERALL THE CARIBBEAN REMAINS FAIRLY QUIET THIS EVENING...WITH
ABUNDANT DRY MID TO UPPER LEVEL AIR ROTATING AROUND THE UPPER
HIGH NEAR THE FLORIDA STRAITS. DEBRIS MOISTURE FROM OUR ATLC
TROPICAL CYCLONES IS AFFECTING THE NE CARIBBEAN FROM 13N-19N
BETWEEN 62W-75W...THOUGH ONLY A FEW ISOLATED SHOWERS/TSTMS ARE
SUSPECTED IN THIS REGION. THIS MOISTURE IS GENERALLY MOVING TO
THE SW BETWEEN AND UPPER TROUGH NE OF THE LEEWARD ISLANDS AND
THE UPPER HIGH OVER THE FL STRAITS. THERE ARE A COUPLE OF SMALL
CLUSTERS OF MODERATE CONVECTION AFFECTING THE SW CARIBBEAN FROM
9N-12N BETWEEN 77W-81W...WITH MORE PRONOUNCED ACTIVITY SEEN OVER
PANAMA AND NRN COLOMBIA. TRADE WINDS APPEAR TO BE MOSTLY IN THE
10 TO 20 KT RANGE THIS EVENING...EXCEPT LIGHTER FAR NW PORTION.

THE ATLANTIC OCEAN..
FLORENCE HAS MOVED OUT OF OUR AREA BUT HAS HELPED TO PUSH A
SURGE OF N/NE WINDS AND COOLER/DRIER AIR SOUTHWARD OFF THE EAST
COAST...AS THE STORM INTERACTS WITH A STRONG 1033MB HIGH OVER
ERN CANADA. SATELLITE IMAGERY AND SFC OBS SUGGESTS A WEAK COLD
FRONT MAY BE FORMING IN ASSOCIATION WITH THIS SURGE OF AIR FROM
THE NORTH...AND THUS WAS ADDED TO THE 2100 UTC MAP EXTENDING E
FROM OFF CNTRL FLORIDA. THIS LARGE FETCH OF NE WINDS WILL
CONTINUE TO GENERATE A MODERATE TO STRONG NE SWELL FOR THE SW
NORTH ATLANTIC THROUGH MIDWEEK...AND DANGEROUS SURF CONDITIONS
FOR BEACHES EXPOSED TO NE SWELL. THIS WILL SLOWLY SUBSIDE
THROUGH THE SECOND PART OF THE WEEK...SEE STATEMENTS FROM LOCAL
WEATHER SERVICE OFFICES FOR MORE INFO. MOST OF THIS REGION IN
THE SW TROPICAL ATLC IS DOMINATED BY DRY MID TO UPPER LEVEL AIR
BETWEEN 65W AND THE EAST COAST. AN UPPER TROUGH IS SEEN SPINNING
NE OF THE LEEWARD ISLANDS. THIS ALONG WITH DEBRIS MOISTURE FROM
FLORENCE IS HELPING TO SUPPORT THE ISOLATED SHOWERS/TSTMS FROM
20N-30N BETWEEN 62W-66W. T.S. GORDON IS JUST E OF THIS AREA AS
DESCRIBED ABOVE. A PERSISTENT UPPER LOW IS SEEN SPINNING NEAR
29N38W THAT ONLY HAS A FEW ISOLATED SHOWERS/TSTMS ASSOCIATED
WITH IT. AN UPPER HIGH REMAINS OFF THE COAST OF AFRICA AND
EXTENDS W TO NEAR 32W. THIS AREA OF THE ERN ATLC OUTSIDE OF THE
TROPICAL WAVES AND LOW MOVING OFF AFRICA IS ALSO DOMINATED BY
SURFACE HIGH PRESSURE EXTENDING S OF THE AZORES.


$$
WILLIS




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