[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071157
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 07 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURE...

HURRICANE DENNIS CENTERED NEAR 17.5N 74.9W OR ABOUT 130 MILES
ESE OF KINGSTON JAMAICA...AND ABOUT 165 MILES S OF GUANTANAMO
CUBA AT 07/1200 UTC MOVING NW 7 KT. MAXIMUM SUSTAINED WIND SPEED
HAS INCREASED TO 90 KT WITH GUSTS TO 110 KT...MAKING DENNIS A
CATEGORY 2 HURRICANE ON THE SAFFIR-SIMPSON SCALE. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 968 MB. SEE 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. THE WHOLE ENVIRONMENT SURROUNDING DENNIS
CONTINUES TO BECOME MORE ORGANIZED...WITH A GOOD CLOUD PATTERN
AND A WELL-ESTABLISHED UPPER LEVEL OUTFLOW. THE FORECAST SHOWS
THAT DENNIS WILL MOVE OVER WATERS WITH A HIGH HEAT CONTENT AND A
PREVAILING LOW WIND SHEAR. IT IS POSSIBLE THAT DENNIS MAY BECOME
A MAJOR HURRICANE. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS
EXTEND FROM 14N TO 19N BETWEEN 71W AND 78W. THIS AREA OF RAIN IS
SOUTH AND SOUTHEAST OF JAMAICA. IMMEDIATELY AROUND THE CENTER
FROM 15N TO 18N BETWEEN 72W AND 75W. STRONG SHOWERS AND
THUNDERSTORMS COVER PRACTICALLY ALL OF THE DOMINICAN
REPUBLIC...ABOUT 60 NM SOUTH OF JAMAICA...AND MOVING AWAY FROM
THE EASTERN END OF CUBA IN THE CARIBBEAN SEA FROM 19N TO 20N
BETWEEN 79W AND 81W. WARMING CLOUD TOP TEMPERATURES AND
DISSIPATING PRECIPITATION ABOUT 450 NM NORTHEAST OF THIS CENTER.
THE PRECIPITATION OVER WESTERN DOMINICAN REPUBLIC HAS DISSIPATED
FOR THE MOMENT. THE HEAVY RAINS ARE REACHING SOUTHERN AND
SOUTHWESTERN HAITI...AND THREATENING JAMAICA FIRST...AND SET TO
THREATEN CUBA AFTER THAT.

...TROPICAL WAVES...

1014 MB LOW PRESSURE CENTER NEAR 11N18W...IN THE MIDDLE OF THE
ITCZ PRECIPITATION...MOVING WEST 10 TO 15 KT. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS WITHIN 30 NM RADIUS OF 12.5N 20.5W.
WIDELY SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND
THUNDERSTORMS ELSEWHERE FROM 10N TO 13N BETWEEN 19W AND 21W.

ATLANTIC OCEAN TROPICAL WAVE ALONG 34W/35W SOUTH OF 20N MOVING
WEST 10 TO 15 KT. NO RAIN IS DIRECTLY ATTRIBUTABLE TO THIS WAVE.
ITCZ SHOWERS AND THUNDERSTORMS ARE FOUND FROM 6N TO 10N BETWEEN
26W AND 30W...AND FROM 5N TO 8N BETWEEN 36W AND 44W.

TROPICAL WAVE ALONG 53W/54W SOUTH OF 16N MOVING WEST 15 KT. THIS
WAVE WAS RETURNED TO ITS 07/0600 UTC SPOT BASED ON SATELLITE
IMAGERY AND INFORMATION FROM THE CAYENNE RAWINSONDE. STRONG
SHOWERS AND THUNDERSTORMS FROM 9N TO 11N BETWEEN 54W AND 57W.
SHOWERS AND THUNDERSTORMS ARE ELSEWHERE FROM 7N TO 14N BETWEEN
50W AND 60W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N17W 10N21W 8N33W 7N54W TO 10N60W.
WIDELY SCATTERED IN GENERAL...WIDELY SCATTERED MODERATE TO
ISOLATED STRONG SHOWERS AND THUNDERSTORMS FROM 5N TO 13N BETWEEN
18W AND 45W.

...DISCUSSION...

THE GULF OF MEXICO...
TROPICAL DEPRESSION CINDY IS INLAND OVER CENTRAL ALABAMA MOVING
NORTHEAST. A SURFACE TROUGH TRAILS FROM THIS FEATURE INTO THE
CENTRAL GULF. ISOLATED SHOWERS AND THUNDERSTORMS ARE WITHIN 15
TO 30 NM ON EITHER SIDE OF THE TROUGH. SOME CONVECTIVE CELLS ARE
MOVING THROUGH THE UPPER TEXAS COAST INTO SOUTHWESTERN
LOUISIANA. A MIDDLE TO UPPER LEVEL TROUGH IS MOVING THROUGH
NORTHEASTERN TEXAS. CYCLONIC FLOW FROM A MIDDLE TO UPPER LEVEL
TROUGH COVERS THE NORTHWESTERN GULF. MIDDLE TO UPPER LEVEL
ANTICYCLONIC FLOW FROM A RIDGE APPROACHES FROM THE ATLANTIC
WATERS ACROSS FLORIDA INTO THE SOUTHEASTERN GULF AND EVENTUALLY
TOWARD THE SOUTHWESTERN GULF.

THE CARIBBEAN SEA...
THE MAIN CONCERN OVER THE CARIBBEAN AT THE MOMENT IS HURRICANE
DENNIS. THE SYSTEM HAS GOOD UPPER LEVEL SUPPORT AND CONTINUES TO
STRENGTHEN.  SEE SPECIAL FEATURES FOR FURTHER DISCUSSION.
ELSEWHERE THE WEATHER IS FAIRLY NICE. DRY AIR ALOFT IS LOCKED IN
AHEAD OF DENNIS' PATH OVER THE NW CARIBBEAN AND IT HAS BEEN
PRODUCING FAIR SKIES WEST OF 78W.

THE ATLANTIC OCEAN...
A WEAK 1019 MB HIGH IS OVER THE W ATLANTIC NEAR 28N75W WHICH
WILL DISSIPATE WITHIN THE NEXT 12 HOURS.  THE TAIL END OF A COLD
FRONT IS FURTHER E ALONG 32N57W 30N60W 29N68W. A STRONG 1035 MB
HIGH NEAR 43N29W DOMINATES THE REMAINDER OF THE ATLANTIC N OF
20N AND E OF 50W.  IN THE UPPER LEVELS...A SHORTWAVE TROF DIGS
DOWN JUST S OF BERMUDA.  AN UPPER LOW IS LOCATED JUST NE OF THE
NRN LEEWARD ISLANDS...NEAR 21N55W BUT THE ADJACENT AREA IS
COVERED BY SO MUCH DRY AIR THAT THERE IS LITTLE ACTIVE WEATHER.
THE UPPER LOW IS CONNECTED TO A SECOND UPPER LOW NEAR THE AZORES
BY A WEAK TROF/SHEAR AXIS WHICH MARKS THE NRN EDGE OF AN AREA OF
STRONG SUBSIDENCE OVER THE E ATLC WATERS. DRY AIR EXTENDS INTO
THE LOW-LEVELS AND REACHES ACROSS THE ENTIRE ATLC TO THE LESSER
ANTILLES...CHARACTERIZED BY STABLE CONDITIONS WITH FLAT
STRATOCUMULUS CLOUDS. THE SUBTROPICAL RIDGE LIES ROUGHLY ALONG
27N60W 32N43W WITH LIGHT EASTERLY TRADES TO THE S.

$$
MT



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