[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 132356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 13 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
2345 UTC.

...SPECIAL FEATURE...
TROPICAL STORM EMILY IS APPROACHING THE WINDWARD ISLANDS. EMILY
WAS NEAR 11.4N 59.8W AT 13/2100 UTC...MOVING WEST OR 275 DEG AT
16 KT WITH AN ESTIMATED CENTRAL PRESSURE OF 1003 MB. THE MAXIMUM
SUSTAINED WIND SPEED WAS 50 KT WITH GUSTS TO 60 KT. PLEASE REFER
TO THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS.

TROPICAL STORM AND HURRICANE WATCHES AND WARNINGS HAVE BEEN
ISSUED BY SEVERAL GOVERNMENTS. A TROPICAL STORM WARNING IS IN
EFFECT FOR BARBADOS...TRINIDAD...TOBAGO...GRENADA...THE
GRENADINES...ST. VINCENT...ST. LUCIA...AND THE NORTHERN COAST OF
VENEZUELA FROM PEDERNALES WESTWARD TO CUMANA...INCLUDING ISLA
MARGARITA. A TROPICAL STORM WATCH IS IN EFFECT FOR BONAIRE...
CURACAO...AND ARUBA...AND FOR THE NORTHERN COAST OF VENEZUELA
FROM CUMANA TO CARACAS...INCLUDING THE OFFSHORE ISLANDS NORTH OF
THE WATCH AREA.

INTERESTS ELSEWHERE IN THE CENTRAL CARIBBEAN SHOULD MONITOR THE
PROGRESS OF EMILY.

THE OUTERMOST BAND OF CONVECTION...ABOUT 30 NM WIDE...HAS RACED
WELL OUT TO THE NW AND CURRENTLY EXTENDS FROM THE BRITISH AND US
VIRGIN ISLANDS S ALONG 14N66W TO VENEZUELA AT 10.5N63.5W.
CONVECTION CONTINUES TO FLARE N OF 13N ALONG THE BAND BUT IS
DISSIPATING TO THE S OF 13N AND MARGARITA MAY ONLY EXPERIENCE
RAIN DURING THE NEXT FEW HOURS. IN CLOSER TO THE CENTER...
NUMEROUS STRONG CONVECTION IS CURRENTLY OBSERVED WITHIN A VERY
SYMMETRICAL 90 NM OF 10.9N59.3W. NORTHERN TRINIDAD AND TOBAGO
AND THE GRENADINES SHOULD BE PREPARED FOR SEVERAL HOURS OF
TROPICAL DOWNPOURS TONIGHT.

LOOKING ALOFT...THE ENVELOPE OF EMILYS OUTFLOW COVERS THE
DISCUSSION AREA WITHIN 300 NM EITHER SIDE OF LINE FROM 8N55W TO
18N65W.

...TROPICAL WAVES...
A TROPICAL WAVE ALONG 35W FROM 6N TO 18N HAS MOVED W 20 KT THE
PAST 24 HOURS. SEVERAL CYCLONIC SWIRLS ARE NOTED ALONG THE WAVE
AXIS...BUT NONE HAVE BEEN PERSISTENT ENOUGH TO BE CARRIED ON THE
SURFACE ANALYSIS AT 18 UTC. ADDITIONALLY...THE LATEST QUIKSCAT
PASS CONFIRMED AN OPEN WAVE. WIDELY SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION CONTINUES TO FLARE WITHIN THE AREA
BOUNDED BY 7N TO 18N BETWEEN 32W AND 41W. WE ARE WATCHING THIS
WAVE CLOSELY FOR SIGNS OF ORGANIZATION.

AN ILL-DEFINED TROPICAL WAVE...OR PERHAPS THE WESTERN PERIPHERY
OF AN EASTERLY LOW LEVEL SURGE...EXTENDS ALONG 5N42W 17N42W.
THIS WAVE HAS MOVED W AT 15 KT THE PAST 24 HOURS. IF THE WAVE TO
ITS E CONTINUES W AT 20 KT IT WILL OVERRUN THIS WAVE DURING THE
NEXT DAY OR SO. WIDELY SCATTERED MODERATE CONVECTION HAS BEEN
ENHANCED ALONG THE ITCZ ALONG 10N...ROUGHLY WITHIN 120 NM EITHER
SIDE OF THE WAVE AXIS...BUT IS UNDERGOING A WEAKENING CYCLE AT
SUNSET TONIGHT.

A TROPICAL WAVE IS MOVING THROUGH THE YUCATAN ALONG 88W TO THE S
OF 20N. MOTION WAS BEEN W AT 12 KT THE PAST 24 HOURS. AN UPPER
LEVEL ANTICYCLONE IS OVER THE GULF OF MEXICO TO THE N AND THE
SOUTHERN EXTENSION OF AN ATLC TUTT IS LOCATED JUST E OF THE
WAVE. THESE FEATURES COMBINED WITH LOCAL SEABREEZE EVENTS IN THE
CARIBBEAN...BAY OF CAMPECHE AND ALONG THE PACIFIC COAST OF
CENTRAL AMERICA...IS CONFUSING THE ACCURATE POSITIONING OF THIS
WAVE. A CLUSTER OF STRONG CONVECTION IS RACING W THROUGH THE E
BAY OF CAMPECHE...BUT THIS IS FAIRLY COMMON AT SUNSET.
CONVECTION IS ALSO LINED UP ALONG THE COAST OF EL SALVADOR AND
GUATEMALA. BUT THE MOST NOTICEABLE CONVECTION IS OVER THE SW
CARIBBEAN INCLUDING THE GULF OF HONDURAS...FROM 5N TO 18N
BETWEEN 80W AND 87W WITH SCATTERED STRONG TSTMS AT SUNSET.

...THE ITCZ...
THE ITCZ EXTENDS OFF THE AFRICAN COAST AT 10N13W TO THE TROPICAL
WAVE AT 13N35W...TO WAVE AT 10N42W...THEN CONTINUES W ALONG 8N
TO NEAR 55W...THEN IS PULLED NW INTO TROPICAL STORM EMILY. A
LARGE CYCLONIC SWIRL IS NOTED NEAR 13N19W...POSSIBLY ANOTHER
TROPICAL WAVE WHICH CAPE VERDE RADIOSIONDE DATA SHOULD DETECT ON
THU...WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION
OBSERVED WITHIN 30 NM EITHER SIDE OF LINE 9N21W 13N18W. OTHER
THAN THE CONVECTION DESCRIBED ALONG THE CENTRAL ATLC WAVES AND
ASSOCIATED WITH EMILY...WIDELY SCATTERED MODERATE CONVECTION IS
OBSERVED FROM 5N TO 11N BETWEEN 42W AND 54W.

...DISCUSSION...
THE GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC IS CENTERED NEAR 25N89W WITH A RIDGE
EXTENDING W OVER OLD MEXICO TO NEAR 24N99W. A RIDGE EXTENDS E
ACROSS N FLORIDA. UPPER DRY AIR IS NOTED OVER THE CENTRAL
GULF...BUT SHOWERS AND TSTMS ARE ENHANCED ALONG THE GULF COAST
FROM S TEXAS TO SW FLORIDA...AND EVERYWHERE S OF 23N. AT THE
SURFACE HIGH PRES IS CENTERED OVER THE NE GULF WITH A RIDGE W
ALONG 27N

THE CARIBBEAN SEA...
ANTICYCLONIC FLOW ALOFT EXTENDS OVER THE WATERS N OF 16N W OF
78W FROM AN ANTICYCLONE CENTERED OVER THE CENTRAL GULF OF
MEXICO. A TUTT EXTENDS SW ACROSS THE CENTRAL CARIBBEAN ALONG
21N73W 11N83W. A SMALL UPPER CYCLONE IS NOTED NEAR 14N68W BUT IS
FILLING RAPIDLY AS THE ANTICYCLONE FROM EMILY BUILDS W ACROSS
THE UPPER LEVELS OF THE E CARIBBEAN. CONVECTION IS ENHANCED
UNDER UPPER DIFFLUENCE TO THE W OF 77W AND TO THE E OF 66W...
WITH DRY UPPER AIR INDICATED BETWEEN 66W AND 73W.

THE ATLANTIC OCEAN...
AN UPPER RIDGE EXTENDS E OFF THE N FLORIDA COAST TO A SHARP
CREST AT 30N70W. IMMEDIATELY TO THE E...A TUTT EXTENDS SW INTO
THE DISCUSSION AREA FROM 32N63W TO SMALL UPPER CYCLONE AT
20N73W. DRY UPPER AIR IS NOTED WITHIN 90 NM EITHER SIDE OF THE
TUTT.
UPPER DIFFLUENCE ENHANCED SHOWERS OVER MAINLAND FLORIDA AND OVER
THE NW BAHAMAS THIS AFTERNOON...WITH RESULTANT DEBRIS MOISTURE
NOW ADVECTED SW ACROSS CUBA INTO THE UPPER LEVELS OF THE NW
CARIBBEAN. WITHIN 420 NM SE OF THE TUTT...ISOLATED MODERATE
CONVECTION IS FLARING WITH DEBRIS MOISTURE OBSERVED WITHIN 120
NM EITHER SIDE OF LINE 32N59W TO 19N72W.

AN UPPER CYCLONE IS OBSERVED NEAR 31N45W WITH ITS FLOW
DOMINATING THE WATERS N OF 26N BETWEEN 51W AND 38W. AN UPPER
RIDGE EXTENDS ALONG 15N10W 15N35W TO 12N48W. DRY UPPER AIR IS
INDICATED WITHIN A 600 NM WIDE BAND CENTERED ALONG 32N19W 27N35W
15N53W. AT THE SURFACE A RIDGE EXTENDS ALONG 32N48W TO 28N80W.

$$
NELSON





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