[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 110603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON SEP 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0530 UTC.

...SPECIAL FEATURES...
THE CENTER OF HURRICANE FLORENCE WAS LOCATED NEAR 31.2N 66.1W OR
ABOUT 110 MILES SOUTHWEST OF BERMUDA AT 11/0600 UTC. FLORENCE IS
MOVING TOWARD THE NORTH NEAR 11 KT AND THIS GENERAL MOTION IS
EXPECTED TO CONTINUE OVERNIGHT WITH A TURN TOWARD THE
NORTH-NORTHEAST ON MONDAY. THE CENTER OF FLORENCE IS EXPECTED TO
PASS NEAR OR JUST WEST OF BERMUDA LATER THIS MORNING. TROPICAL
STORM FORCE WINDS CONTINUE TO AFFECT BERMUDA. MINIMUM CENTRAL
PRESSURE IS 975 MB. MAXIMUM SUSTAINED WINDS REMAIN NEAR 80 KT
WITH GUSTS TO 100 KT. FLORENCE IS A LARGE TROPICAL CYCLONE.
HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 60 MILES...95
KM...FROM THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND
OUTWARD UP TO 260 MILES...415 KM. SOME STRENGTHENING IS STILL
POSSIBLE BEFORE FLORENCE BYPASSES BERMUDA. 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. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION LIES FROM 28N-33N BETWEEN
64W-67W WITH A LARGE SHIELD OF SCATTERED MODERATE CONVECTION
STRETCHED OUT TO THE N BY THE UPPER TROUGH. FLORENCE IS EXPECTED
TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 5 TO 8 INCHES OVER
BERMUDA...WITH POSSIBLE MAXIMUM AMOUNTS OF 10 INCHES.

TROPICAL DEPRESSION SEVEN HAS FORMED EAST-NORTHEAST OF THE
LEEWARD ISLANDS. AT 11/0300 UTC THE CENTER OF TROPICAL
DEPRESSION SEVEN WAS LOCATED NEAR 20.2N 54.5W OR ABOUT 525
MILES...845 KM...EAST-NORTHEAST OF THE LEEWARD ISLANDS. THE
DEPRESSION IS MOVING SLOWLY TO THE WEST NEAR 5 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1012 MB. MAXIMUM SUSTAINED WINDS ARE
NEAR 25 KT WITH GUSTS TO 35 KT. FOR MORE DETAILS PLEASE READ THE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC OR THE PUBLIC ADVISORY UNDER
MIATCPAT2/WTNT32 KNHC. THIS TROPICAL CYCLONE...VERY MUCH UNLIKE
FLORENCE...IS COMPACT. OVER THE PAST COUPLE OF DAYS THIS SYSTEM
WAS FEELING THE EFFECTS OF NORTHERLY WIND SHEAR EXPOSING THE LOW
LEVEL CENTER TO THE NORTH. HOWEVER...IT ESCAPED THE SHEAR ON
SUNDAY HELPING THE CONVECTION TO WRAP AROUND THE CENTER.
SCATTERED MODERATE CONVECTION EXISTS FROM 18N-21N BETWEEN
53W-57W...STRONGEST TO THE SOUTH OF THE CENTER. SOME
STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS...AND THE
DEPRESSION COULD BECOME A TROPICAL STORM ON MONDAY.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE E ATLC ALONG 29W S OF 18N MOVING W
NEAR 10 KT. THE OVERALL STRUCTURE OF THIS WAVE HAS BECOME MORE
DISORGANIZED THAN IT WAS OVER THE PAST COUPLE OF DAYS.
LOW TO MID CLOUD MOTIONS DO SHOW SOME CYCLONIC TURNING FROM
8N-14N ABOUT THE AXIS. SCATTERED SHOWERS AND TSTMS EXIST WITHIN
300 NM EITHER SIDE OF THE AXIS S OF 10N. SOME INTERACTION WITH A
LARGE UPPER LOW TO THE NNW IS TRIGGERING A LINE OF SIMILAR
ACTIVITY FROM 18N-23N BETWEEN 28W-30W.

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 42W SOUTH OF 15N MOVING
WEST 10 TO 15 KT. THIS WAVE IS SLIGHTLY MORE DISCERNIBLE
COMPARED TO YESTERDAY BASED ON SATELLITE IMAGES. SHOWER/TSTM
ACTIVITY IS DISORGANIZED BUT HAS BECOME SLIGHTLY STRONGER AND
EXPANDED IN COVERAGE FROM 10N-12N BETWEEN 41W-48W.

A TROPICAL WAVE IS ALONG 55W S OF 17N MOVING W NEAR 10 KT. THIS
WAVE AT LEAST IN PART SPAWNED THE DEVELOPMENT OF TROPICAL
DEPRESSION SEVEN. THE WAVE APPEARED TO HAVE SPLIT...THE SOUTHERN
PORTION IS PROPAGATING W WITH SLIGHT VEERING IN THE LOW LEVEL
CLOUDS ABOUT THE AXIS. THIS IS THE LOW AMPLITUDE FEATURE THAT
WILL BE TRACKED. SHOWER ACTIVITY IS MAINLY BEHIND THE WAVE AXIS
AND ENHANCED BY THE ITCZ AND THE WAVE TO ITS EAST.

TROPICAL WAVE ALONG 94W HAS MOVED INTO THE EPAC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N13W 8N21W 10N39W 9N61W. BESIDES
FOR THE CONVECTION DISCUSSED IN THE TROPICAL WAVES
SECTION...SCATTERED MODERATE IS MOVING OFF THE W COAST OF AFRICA
E OF 20W FROM 6N-15N ASSOCIATED WITH A WELL DEFINED TROPICAL
WAVE AND LOW PRES SYSTEM THAT WILL LIKELY MOVE OFF THE COAST IN
THE NEXT DAY OR SO.

...DISCUSSION...

THE GULF OF MEXICO...
A CONSIDERABLE AMOUNT OF UPPER LEVEL MOISTURE LIES OVER MUCH OF
THE GULF N OF 24N. THIS SEEMS MOSTLY ASSOCIATED WITH UPPER
DIFFLUENCE BETWEEN AN UPPER HIGH OVER CENTRAL MEXICO NEAR
23N103W WITH RIDGING EXTENDING ACROSS THE GULF ALONG 27N AND
BROAD WESTERLY FLOW OVER THE SOUTHERN U.S. HOWEVER...MOST OF THE
DEEP MOISTURE OR SHOWER ACTIVITY HAS DISSIPATED OVER THE PAST
FEW HOURS LEAVING ONLY ISOLATED SHOWERS EMBEDDED IN THE MOISTURE
PLUME. A SFC TROUGH WAS ANALYZED IN REGION EARLIER...HOWEVER SFC
OBS AND QUIKSCAT DATA SUGGEST THAT THE TROUGH IS FAIRLY WEAK IF
THERE AT ALL. S OF 24N....MOISTURE IS MORE SCATTERED WITH A
PATCH OF SHOWERS AND TSTMS IN THE E BAY OF CAMPECHE FROM 18N-21N
BETWEEN 90W-93W AND A FEW SHOWERS N OF CUBA MOVING TOWARDS THE
KEYS. SFC EAST TO SOUTHEASTERLY WINDS ARE FAIRLY LIGHT DUE TO
THE WEAK PRES GRAD. LITTLE PATTERN CHANGE IS EXPECTED OVER THE
NEXT DAY OR TWO. GFS SUGGESTS THAT A COLD FRONT MAY ENTER THE NW
GULF ON WED.

THE CARIBBEAN SEA...
THE WEATHER IN THE CENTRAL CARIBBEAN IS VERY QUIET...THANKS TO
DRY STABLE AIR ALOFT TO THE SOUTH OF AN UPPER ANTICYCLONE
CENTERED JUST N OF HISPANIOLA. MODERATE SUBSIDENCE LIES BETWEEN
68W AND 80W. THERE IS A LITTLE MORE MOISTURE IN THE E CARIBBEAN
WITH MAINLY MID-HIGH LEVEL CLOUDINESS AND ISOLATED SHOWERS E OF
68W ACROSS THE LESSER ANTILLES. THIS IS MAINLY ASSOCIATED WITH
DEBRIS MOISTURE FROM NEWLY FORMED TROPICAL DEPRESSION SEVEN.
SIMILAR WEATHER EXISTS IN THE W CARIBBEAN WHERE A FAIR AMOUNT OF
MOISTURE WITH EMBEDDED SCATTERED SHOWERS ARE FOUND W OF 80W.
THIS ACTIVITY IS ASSOCIATED WITH AN UPPER LEVEL LOW WHICH IS
SEEN SPINNING ON WATER VAPOR IMAGES JUST E OF THE YUCATAN
PENINSULA. MUCH MORE ORGANIZED SHOWERS AND TSTMS ARE OVER
CENTRAL AMERICA AND S MEXICO WHERE UPPER DIFFLUENCE IS STRONGER
AND THERE IS ENHANCEMENT IN THE LOW LEVELS FROM TROPICAL WAVES
IN THE EPAC AND THE ITCZ. AT THE SURFACE...TRADES ARE FAIRLY
LIGHT 10 TO 15 KT WITH A WEAK PRESSURE GRADIENT LEFT S OF
FLORENCE.

THE ATLANTIC OCEAN...
HURRICANE FLORENCE AND TROPICAL DEPRESSION SEVEN ARE THE
HIGHLIGHTS. FLORENCE IS ROUNDING THE SUBTROPICAL RIDGE...WHICH
COVERS THE REGION FROM 40W-66W...AND HAS LIKELY BEGAN ITS
RECURVATURE. AN UPPER TROUGH LIES TO THE W OF THIS RIDGE OFF THE
E COAST OF THE U.S. WHICH HAS CAUSED THE SIGNIFICANT BREAK IN
THE RIDGE SUPPORTED THIS STEERING REGIME FOR FLORENCE. SCATTERED
MODERATE CONVECTION EXISTS FROM 29N-33N BETWEEN 64W-67W. ANOTHER
MORE WIDESPREAD BATCH OF CONVECTION LIES TO THE N STRETCHED OUT
BY THE UPPER TROUGH. LONG PERIOD SWELL ASSOCIATED WITH FLORENCE
HAS ALREADY BEGUN REGISTERING ON MOST EAST COAST BUOYS...THUS
DANGEROUS SURF IS EXPECTED FROM FLORIDA THROUGH NEW ENGLAND AND
WILL PERSIST OVER THE NEXT COUPLE OF DAYS. SEE STATEMENTS FROM
LOCAL WEATHER SERVICE OFFICES FOR DETAILS ON COASTAL CONDITIONS.
ABOUT 900 NM TO THE SE OF FLORENCE LIES NEWLY FORMED T.D. 7.
UNLIKE FLORENCE THIS IS A SMALL SYSTEM WITH SCATTERED MODERATE
CONVECTION FOUND FROM 17N-21N BETWEEN 53W-57W. FOR MORE DETAILS
REFER TO THE SPECIAL FEATURE SECTION. FARTHER EAST...A MID TO
UPPER LOW IS CENTERED NEAR 26N34W. ISOLATED TO SCATTERED
SHOWERS/TSTMS ARE SPINNING CYCLONICALLY AROUND THE UPPER LOW
FROM 20N-30N BETWEEN 30W-37W. A LARGE MID-UPPER RIDGE IS
CENTERED JUST S OF THE CANARY ISLANDS WITH THE RIDGE AXIS
EXTENDING SWWARD TO NEAR 12N40W. A WELL-DEFINED TROPICAL WAVE
AND LOW-MID LEVEL LOW PRES SYSTEM IS MOVING OFF THE COAST OF
AFRICA GENERATING SCATTERED SHOWERS AND TSTMS E OF 20W FROM
6N-15N.

$$
CANGIALOSI






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