[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 101801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN JUL 10 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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...
AT 1 PM CDT...1800Z...THE CENTER OF HURRICANE DENNIS WAS LOCATED
NEAR LATITUDE 29.9 NORTH...LONGITUDE 86.9 WEST.  THIS IS ABOUT
40 MILES SOUTHEAST OF PENSACOLA FLORIDA. DENNIS IS MOVING NNW 16
KT AND THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 940 MB. THE
MAXIMUM SUSTAINED WIND SPEED IS 115 KT WITH GUSTS TO 140 KT. SEE
THE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT4/WTNT34 KNHC AND THE FORECAST/ ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.  VISIBLE
SATELLITE PICTURES INDICATE A SMALL CLOUD-FILLED EYE NEAR THE
CENTER OF THE CENTRAL DENSE OVERCAST (CDO) CLOUDS.  THE EYE IS
BECOMING A BIT LESS DISTINCT WITH TIME AS SLY SHEAR COMBINED
WITH SLIGHTLY COOLER SHELF WATERS ARE LIKELY TAKING A TOLL ON
THE HURRICANE.  THE EYE SHOULD BE MAKING LANDFALL IN THE NEXT
FEW HOURS.  SCATTERED MODERATE CONVECTION IS FROM 28N-32N
BETWEEN 82W AND MOBILE.

CENTRAL ATLC TROPICAL WAVE ALONG 40W/41W S OF 17N MOVING W 10-15
KT WITH A 1013 MB LOW ALONG THE WAVE NEAR 10N.  BANDS OF TSTMS
AROUND THE LOW ARE MORE DISTINCT AND STRONGER THAN YESTERDAY
WITH TROPICAL CYCLONE FORMATION POSSIBLE WITHIN 36 HOURS.
VERTICAL WIND SHEAR IS VERY LOW AND THE SYSTEM WILL BE MOVING
OVER PROGRESSIVELY WARM WATER TEMPERATURES.  COMPUTER MODELS
SUGGEST THE LOW WILL MOVE W TO WNW AT ABOUT 10 KT AND REGARDLESS
OF DEVELOPMENT... BRING A GOOD CHANCE OF RAIN TO THE LESSER
ANTILLES BY LATE WED.

...TROPICAL WAVES...

TROPICAL WAVE PREVIOUSLY ALONG 40W/41W NOW A SPECIAL FEATURE.

TROPICAL WAVE ALONG 69W SOUTH OF 17N MOVING WEST 10 TO 15 KT.
THE CURACAO SOUNDING THIS MORNING INDICATES THAT THE WAVE HAD
PASSED WITH SE WINDS IN THE LOW/MID LEVELS.  SATELLITE IS NOT AS
SUGGESTIVE OF THE EXACT POSITION WITH A LARGE AREA OF
SHOWERS/TSTMS IN THE SE CARIBBEAN DUE TO THE INTERACTION OF THE
WAVE WITH A MID/UPPER TROUGH.

...ITCZ...

ITCZ AXIS IS ALONG 10N14W 9N25W 10N35W 6N47W 8N59W.  ISOLATED
MODERATE CONVECTION WITHIN 60 NM OF AXIS BETWEEN 30W-60W.
WIDELY SCATTERED MODERATE CONVECTION FROM 7N-10N BETWEEN 18W-30W.

...DISCUSSION...

GULF OF MEXICO...
DENNIS CONTROLS THE WEATHER IN THE ERN GULF OF MEXICO THOUGH ITS
INFLUENCE SHOULD BE FADING AS IT MOVES FARTHER N.  A FEW
RAINBANDS ARE AS FAR S AS MIAMI TODAY WITH A LONG INFLOW TAIL ON
THE SE SIDE.  MID/UPPER LOW NEAR 27N94W HAS A FEW COLD-AIR
INSTABILITY TSTMS WITHIN 60 NM OF THE CENTER... OTHERWISE THE
ATMOSPHERE IS TOO STABLE AND DRY TO SUPPORT ANY SIGNIFICANT
CONVECTION W OF 90W.  MID/UPPER RIDGING IS FROM CUBA TO CENTRAL
FLORIDA... IMPARTING A SLY SHEAR ON DENNIS AND CAUSING A HUGE
EXPANSION OF THE OUTFLOW ON THE N SIDE OF THE CYCLONE.  NE
FLORIDA IS LIKELY TO STAY RELATIVELY WET AS THE TAIL OF DENNIS
MOVES THRU THE REGION TOMORROW INTO MON.  VERY DRY CONDITIONS
REMAINS FOR TEXAS.

CARIBBEAN SEA...
ANTICYCLONIC OUTFLOW FROM DENNIS COVERS THE AREA W OF 80W WITH
THIN CIRRUS THRU THE REGION.  A MID/UPPER LOW IS NEAR 15N71W
MOVING W 10-15 KT AND IS RESPONSIBLE FOR ENHANCING A TROPICAL
WAVE'S CONVECTION WITH WIDELY SCATTERED MODERATE CONVECTION FROM
12.5N-15.5N BETWEEN THE LESSER ANTILLES AND 70W.  FARTHER SE...
MID/UPPER RIDGING EXTENDS FROM NEAR TRINIDAD TO 12N66W AND IS
BRINGING DRIER AIR IN THE MID/UPPER LEVELS THRU THE WINDWARD
ISLANDS.  DRY WEATHER IS EXPECTED IN THE LEEWARD/WINDWARD
ISLANDS FOR THE NEXT COUPLE OF DAYS UNTIL THE WAVE/LOW AROUND
40W APPROACHES THE AREA ON WED.  THE LATEST GFS SUGGESTS THAT
THE LOW COULD BE A THREAT TO THE AREA IF IT DEVELOPS.

ATLANTIC OCEAN...
NARROW RIDGING EXTENDS FROM NE TO NEAR BERMUDA EASTWARD TO
32N50W IN THE CENTRAL ATLC.  BENEATH THE RIDGE THERE IS A
MID/UPPER LOW NEAR 23N64W MOVING W 10 KT ALONG WITH VERY DRY AIR
IN THE MID/UPPER LEVELS N OF 20N W OF 50W.  A FEW INSTABILITY
TSTMS ARE POSSIBLE NEAR THE LOW CENTER... OTHERWISE THE AREA IS
QUIET.  FARTHER E... MID/UPPER TROUGH EXTENDS FROM 20N43W TO
31N33W WITH LITTLE SENSIBLE WEATHER DUE TO VERY DRY AIR ALOFT.
A WEAK MID/UPPER TROUGH IS MOVING ACROSS THE CANARY
ISLANDS...OTHERWISE THE E ATLC IS DOMINATED BY UPPER RIDGING
EXTENDS FROM W MAURITANIA THRU THE NW CAPE VERDES TO 15N43W WITH
A WEAK INVERTED TROUGH S OF 20N ALONG 48W.  VERTICAL WIND SHEAR
REMAINS MUCH LOWER THAN AVERAGE IN THE DEEP TROPICS... ALONG
WITH WEAKER TRADES THAN NORMAL.

$$
BLAKE

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