[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 082350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUL 08 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...
HURRICANE DENNIS IS NEAR 22.6N 81.1W OR ABOUT 95 MILES ... 150
KM... EAST-SOUTHEAST OF HAVANA CUBA AND ABOUT 145 MILES...235
KM...SOUTH-SOUTHEAST OF KEY WEST FLORIDA AT 2100 UTC ON THE
MOVING NW 15 KT.  MAXIMUM SUSTAINED WINDS ARE 115 KT GUSTING TO
140 KT AND THE MINIMUM CENTRAL PRESSURE IS 949MB.  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.  THE HURRICANE
HAS BEEN A RECORD-BREAKER SO FAR... BEING THE EARLIEST CATEGORY
4 IN THE CARIBBEAN SEA AND THE STRONGEST HURRICANE IN THE ATLC
BASIN SO EARLY IN THE YEAR.  THE EYE IS NOT AS DEFINED AS PRIOR
TO THIS SECOND LANDFALL OVER CUBA.  ANTICYCLONIC OUTFLOW
CONTINUES TO BE IMPRESSIVE.  INTERACTION WITH LAND HAS WEAKENED
THE SYSTEM SOME BUT EXPECT IT TO EMERGE INTO THE GULF OF MEXICO
OVERNIGHT WHERE UPPER LEVEL WINDS ARE FAVORABLE FOR
REINTENSIFICATION.  THERE IS A SLIGHT ASYMMETRY TO THE CLOUD
PATTERN WITH MOST OF THE SHOWERS/TSTMS ON THE SE SIDE OF THE
SYSTEM WITH A LITTLE BIT OF NW SHEAR FAVORING CONVECTIVE
DEVELOPMENT BEHIND THE HURRICANE.  A RAINBANDS ARE MOVING
THROUGH THE FLORIDA KEYS INTO S FLORIDA AND THE CENTRAL
BAHAMAS.  SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
FROM 17N-23N BETWEEN 77W-83W.

...TROPICAL WAVES...
TROPICAL WAVE IS NEAR THE CAPE VERDE ISLANDS ALONG 26W S OF 18N
MOVING W 10-15 KT.  THERE IS A 1013 MB LOW ALONG THE WAVE NEAR
12N.  THE E ATLC HAS A COMPLICATED STRUCTURE RIGHT NOW WITH
ANOTHER 1013 MB LOW FURTHER W NEAR 11N35W.  THESE SYSTEMS
APPEARS TO BE SLOWLY MOVING WESTWARD AND IT IS DIFFICULT TO
DETERMINE IF THEY ARE BOTH ASSOCIATED WITH TROPICAL WAVES.  A
FEW TSTMS ARE BEING GENERATED BY THE LOWS THOUGH THE WESTERN ONE
IS ABOUT TO ENTER MUCH DRIER AIR ALOFT.

CENTRAL ATLC TROPICAL WAVE IS ALONG 42W MOVING W 10-15 KT.
WAVE CAN BE SEEN IN THE STRATOCUMULUS FIELD THOUGH ITS CLOUD
SIGNATURE IS FADING.  NO SIGNIFICANT CONVECTION IS NOTED.

W-CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 59W S OF 16N MOVING
WEST 10-15 KT. ISOLATED MODERATE CONVECTION IS  OVER THE
WINDWARD ISLANDS FROM 11N-15N BETWEEN 55W-62W.  INCREASED LEVELS
OF MOISTURE ARE LIKELY FOR TOMORROW OVER THE WINDWARD ISLANDS
WITH SIGNIFICANT DRYING BY LATE SAT.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N16W 11N20W 12N30W 8N40W 5N53W.
SCATTERED MODERATE CONVECTION IS FROM 11N-14N BETWEEN 26W-31W.
ISOLATED MODERATE CONVECTION IS FROM 6N-8N BETWEEN 28W-38W.

...DISCUSSION...

GULF OF MEXICO...
DENNIS HAS STARTED TO EFFECT THE GULF OF MEXICO WITH CONVECTION
OVER CUBA AND FLORIDA.  SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS OVER FLORIDA FROM 24N-30N BETWEEN 81W-84W.  MOSTLY
FAIR WEATHER DOMINATES THE REMAINDER OF THE GULF OF MEXICO.  IN
THE UPPER LEVELS...AN ANTICYCLONIC CIRCULATION IS CENTERED NEAR
24N80W WITH SIGNIFICANT MOISTURE E OF 86W.  A CYCLONIC
CIRCULATION IS OVER THE BAY OF CAMPECHE NEAR 21N93W WITH STRONG
SUBSIDENCE W OF 86W.  EXPECT DENNIS TO CONTINUE N TO THE NE
GULF.

CARIBBEAN SEA...
HURRICANE DENNIS CONTINUES TO CHURN OVER CUBA WITH THE CENTER NOW
S OF MATANZAS CUBA.  VERY HEAVY RAIN SHOULD CONTINUE OVER THE
ISLAND INTO TOMORROW WITH LINGERING ACTIVITY IN W CUBA THROUGH
SUN.  KINGSTON JAMAICA RECEIVED ALMOST 12 INCHES OF RAIN AS THE
CYCLONE PASSED YESTERDAY.  OUTSIDE OF DENNIS.. THE WEATHER IS
RATHER QUIET WITH NE FLOW IN THE UPPER LEVELS CONTROLLING THE
REGION W OF 70W.  A MID/UPPER TROUGH EXTENDS THROUGH THE
LEEWARD/WINDWARD ISLANDS DOWN TO ABOUT TRINIDAD AND IS ENHANCING
A TROPICAL WAVE'S CONVECTION LOCATED NEAR BARBADOS.  A PUSH OF
DRIER AIR ALOFT IS PREVENTING SHOWER DEVELOPMENT IN THE LEEWARD
ISLANDS.  MOISTURE FROM THE TROPICAL WAVE COULD OVERSPREAD
PUERTO RICO ON SUN.

ATLANTIC OCEAN...
A WEAK 1023 MB HIGH IS OVER THE W ATLANTIC NEAR 29N67W.  A
SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC ALONG 32N53W
24N63W.  ISOLATED MODERATE CONVECTION IS FROM 24N-26N BETWEEN
60W-63W.  A 1028 MB HIGH N OF THE AZORES DOMINATES THE REMAINDER
OF THE ATLANTIC N OF 20N AND E OF 50W.  PRESSURES ARE HIGHER
THAN AVERAGE IN THE DEEP TROPICS THOUGH THEY ARE NEAR AVERAGE IN
THE SUBTROPICS... SUPPORTING A PRESSURE GRADIENT WEAKER THAN
AVERAGE AND CONSEQUENTLY LIGHTER TRADES THAN NORMAL.  IN THE
UPPER LEVELS...MID/UPPER RIDGING EXTENDS FROM NE FLORIDA THROUGH
BERMUDA WITH A WEAK CYCLONIC CIRCULATION TRAPPING BENEATH THE
RIDGE NEAR 26N70W.  OUTFLOW FROM DENNIS COVERS THE BAHAMAS AND
THE REST OF THE SW ATLC S OF 27N W OF 67W WITH VERY DRY AIR
ALOFT N OF THAT REGION.  A MID/UPPER CYCLONIC CIRCULATION NEAR
21N60W EXTENDS SSW INTO THE LESSER ANTILLES.  MODERATE TO STRONG
SUBSIDENCE COVERS THE CENTRAL ATLC W OF 35W TO THE TROUGH AXIS
BETWEEN 10N-30N.  A BROAD TROUGH IS AT THE NORTHERN FRINGE OF
THE CENTRAL ATLC N OF 27N E OF 40W.  THE TYPICAL AFRICAN
ANTICYCLONE IS OVER WESTERN SAHARAN NEAR 22N16W WITH RIDGE AXIS
WSW TO 16N46W.  INVERTED TROUGH IS ALONG 35W S OF 20N CREATING A
SMALL BREAK IN THE RIDGE.  ELY FLOW IS A BIT DIFFLUENT..
SUPPORTING TSTMS NEAR THE TWO CYCLONIC CIRCULATIONS.

$$
FORMOSA




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