[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181040
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 18 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
1015 UTC.

...SPECIAL FEATURES...

TROPICAL STROM IRENE IS CENTERED NEAR 41.3N 51.0W AT 18/0900 UTC
MOVING NE AT 30 KT. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH
GUSTS TO 75 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 990 MB.
SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. IRENE HAS REALLY
ACCELERATED OFF TO THE NE AS IT IS BEING SWEPT UP BY THE
APPROACHING FRONTAL BOUNDARY AND IS BECOMING EXTRATROPICAL.
CONVECTION IS WELL TO THE NE OF THE LOW LEVEL CENTER. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 41N-44N BETWEEN
47W-51W.

A 1012 MB LOW...REMNANT OF TROPICAL DEPRESSION TEN...IS CENTERED
NEAR 17.5N59W MOVING NW 5-10 KT. CONVECTION HAS REGENERATED
AGAIN TONIGHT BUT HAS NOT REDEVELOPED INTO A TROPICAL SYSTEM.
CONDITIONS ARE BECOMING MORE FAVORABLE FOR REDEVELOPMENT AND A
RECONNAISSANCE FLIGHT IS SCHEDULED FOR LATER THIS AFTERNOON.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM WITHIN 120
NM RADIUS OF 18.5N58W.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS APPROACHING THE CAPE VERDE ISLANDS ALONG
22W S OF 23N WITH A 1011 MB LOW ALONG THE WAVE NEAR 16N MOVING W
5-10 KT. THERE IS NO ASSOCIATED DEEP CONVECTION BUT WITH THE
ABUNDANT OF TROPICAL MOISTURE OVER THE AREA THE CAPE VERDE
ISLANDS COULD RECEIVE SCATTERED SHOWERS FROM THE SYSTEM OVER THE
NEXT DAY OR TWO.

CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 51W/52W S OF 19N MOVING
W 10-15 KT. THE WAVE CONTINUES TO MARK THE LEADING EDGE OF AN
AFRICAN DUST SURGE. AS SUCH...THERE IS NO ASSOCIATED DEEP
CONVECTION WITH THIS WAVE.

S GULF OF MEXICO TROPICAL WAVE IS ALONG ALONG 93W S OF 22N
MOVING W 10-15 KT. WAVE IS BENEATH N FLOW RESULTING FROM AN
UPPER HIGH MOVING ACROSS MEXICO. THEREFORE... ASSOCIATED DEEP
CONVECTION IS IN THE E PACIFIC REGION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 19N16W 10N27W 8N39W 11N63W. CLUSTERS
OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 120
NM OF THE AXIS FROM 28W-37W AND FROM 6N-10N BETWEEN 22W-26W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE AREA S OF 12N
TO THE COAST OF SOUTH AMERICA BETWEEN 54W-60W.

...DISCUSSION...

GULF OF MEXICO...
THE UPPER HIGH IS MOVING ACROSS MEXICO NEAR 20N100W PRODUCING NW
TO N UPPER FLOW OVER THE BAY OF CAMPECHE. AN UPPER LOW MOVING
INTO THE NW GULF IS CENTERED NEAR 28N92W WITH CYCLONIC FLOW N OF
23N W OF 87W. AN UPPER HIGH OVER S GEORGIA WITH A RIDGE AXIS
EXTENDING INTO THE W ATLC IS PRODUCING DIFFLUENT FLOW OVER THE E
GULF GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS OVER THE STRAITS OF FLORIDA. ALTHOUGH UPPER LEVEL
MOISTURE IS ABUNDANT...ONLY SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS DOT THE W GULF W OF 88W. OVERALL THE N GULF COAST
REMAINS RELATIVITY UNDER CLEAR SKIES. DEEP LAYERED MOISTURE WILL
CONTINUE TO POOL OVER THE S GULF THROUGH THE WEEKEND AS TROPICAL
MOISTURE FROM THE CARIBBEAN CONTINUES TO MOVE ACROSS THE AREA.

CARIBBEAN...
A LARGE MID/UPPER LOW IS CENTERED OVER THE W CARIBBEAN OFF THE
COAST OF CENTRAL AMERICA NEAR 14N82W WITH AN UPPER TROUGH
EXTENDING ENE TO OVER HISPANIOLA. THE UPPER LOW IS PULLING NE
FLOW OVER THE W CARIBBEAN WITH SOMEWHAT DRIER UPPER AIR AS WELL.
UPPER LEVEL TROPICAL MOISTURE IS POOLING OVER THE S CARIBBEAN SE
OF THE UPPER TROUGH AXIS GENERATING WIDESPREAD CLOUDINESS WITH
TWO AREAS OF DEEP CONVECTION. SCATTERED MODERATE/STRONG
CONVECTION IS IN THE SW CARIBBEAN WITHIN A 90 NM RADIUS OF
13N80W AND WITHIN 75/90 NM OF LINE FROM 16N71W TO THE COAST OF
COLOMBIA NEAR 12.5N71.5W THEN W TO 12N76W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS DOT THE CARIBBEAN  W OF 69W WITH
THE HIGHEST CONCENTRATION S OF 12N W OF 80W AND OVER PANAMA. THE
E CARIBBEAN TO OVER THE LEEWARD ISLANDS ARE UNDER W UPPER FLOW
FROM AN UPPER LOW N OF PUERTO RICO NEAR 23N66W. DEEP LAYERED
MOISTURE WILL REMAIN ACROSS MOST OF THE CARIBBEAN THROUGH THE
WEEKEND WITH THE LOW LEVEL EASTERLY TRADES INCREASING FRI INTO
SAT.

ATLANTIC...
THE UPPER LEVEL HIGH IS CENTERED OVER S GEORGIA WITH A RIDGE
AXIS EXTENDING INTO THE W ATLC TO NEAR 28N73W. THE RIDGE IS
RESPONSIBLE FOR MOSTLY SUBSIDENCE CONDITIONS SO THERE ARE NO
SHOWERS/THUNDERSTORMS BETWEEN 24N-30N W OF 74W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS MOVING S INTO THE REGION
ASSOCIATED WITH A FRONTAL BOUNDARY N OF 32N. THE NEAR STATIONARY
UPPER LOW IS CENTERED NEAR 33N43W WITH AN UPPER TROUGH EXTENDING
SW TO 23N51W. A SECOND UPPER LOW IS CENTERED N OF PUERTO RICO
NEAR 23N66W AND HAS BECOME CUT OFF FROM THE LONG WAVE TROUGH. TO
THE W OF THE UPPER LOW NEAR 33N A SURFACE TROUGH EXTENDS THROUGH
32N52W SW ALONG 26N61W TO THE WINDWARD PASSAGE. BROAD SWATH OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS EXTENDS WITHIN 120/150
NM OF THE SURFACE TROUGH TO OVER THE GREATER ANTILLES FROM
HISPANIOLA TO ACROSS CUBA. SIMILAR ACTIVITY IS SE OF THE UPPER
LOW NEAR 33N FROM 26N-30N BETWEEN 41W-47W. S OF THE UPPER TROUGH
IN THE CENTRAL ATLC IS AN UPPER HIGH THAN HAS BEEN NARROWED
SIGNIFICANTLY 20N42W. THE E ATLC IS DOMINATED BY A LARGE UPPER
HIGH MOVING OFF THE COAST OF WESTERN SAHARA NEAR 21N16W WITH A
RIDGE EXTENDING FROM W TO 20N35W. THE SURGE OF AFRICAN DUST IS
BEING WEDGED BETWEEN THESE HIGHS FROM 20N-25N BETWEEN 40W-51W.
TROPICAL MOISTURE REMAINS ALONG THE AFRICAN COAST AND COULD
BRING SCATTERED SHOWERS TO THE CAPE VERDE ISLANDS AS THE
LOW/TROPICAL WAVE PASSES.

$$
WALLACE



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