[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 310626
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN JUL 31 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 0000 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 0545 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 43W/44W SOUTH OF 19N MOVING WEST 15-20 KT.
ISOLATED MODERATE SHOWERS FROM 11N TO 16N BETWEEN 43W AND 51W.

TROPICAL WAVE ALONG 56W/57W SOUTH OF 20N MOVING WEST 20 KT.
ANY LOW PRESSURE CENTER WITH THIS WAVE AT 30/1800 UTC WAS NOT
APPARENT AT 31/0000 UTC. SCATTERED STRONG SHOWERS AND
THUNDERSTORMS FROM 12N TO 14N BETWEEN 57W AND 59W...AND FROM
18N TO 20N BETWEEN 59W AND 60W. SCATTERED MODERATE TO ISOLATED
STRONG SHOWERS AND THUNDERSTORMS ELSEWHERE FROM 10N TO 14N
BETWEEN 55W AND 57W. CONVECTIVE DEBRIS CLOUDS FROM ACTIVITY
WHICH HAS WEAKENED IS FROM 15N TO 17N BETWEEN 57W AND 60W.
CONDITIONS MAY BECOME SOMEWHAT MORE FAVORABLE FOR DEVELOPMENT
DURING THE NEXT 24-36 HOURS AS THE WAVE MOVES AROUND THE SW
PERIPHERY OF THE MID/UPPER LEVEL HIGH OVER THE CENTRAL ATLC.
ON ITS CURRENT MOTION...SHOWERS AND THUNDERSTORMS WILL BEGIN
TO AFFECT THE WINDWARD ISLANDS ON SUNDAY WITH GUSTY WINDS AND
LOCALLY HEAVY RAINS.

A WELL-DEFINED CENTRAL CARIBBEAN SEA AND SOUTHWESTERN ATLANTIC
OCEAN TROPICAL WAVE EXTENDS FROM 24N70W TO 16N72W TO NORTHERN
COLOMBIA NEAR 8N73W. ISOLATED TO WIDELY SCATTERED MODERATE/
LOCALLY STRONG SHOWERS AND THUNDERSTORMS FROM JUST SOUTH OF
PUERTO RICO NEAR 17N INTO THE ATLANTIC WATERS TO 25N BETWEEN
58W AND 70W. THIS WAVE STILL IS UNDER AN UPPER LEVEL RIDGE.
THIS RIDGE HAS BECOME EVEN MORE AMPLIFIED THAN IT WAS 24 HOURS
AGO. HEAVY RAINS ...FLOODING...AND POSSIBLE MUDSLIDES WILL
CONTINUE TO AFFECT HISPANIOLA THIS EVENING AND TONIGHT. THIS
ACTIVITY ALSO WILL BEGIN AFFECTING THE SOUTHERN BAHAMAS AND
EASTERN CUBA LATER TONIGHT THEN SPREAD ACROSS THE REMAINDER
OF THE BAHAMAS AND WESTERN CUBA ON SUNDAY.

...THE ITCZ...

ITCZ 12N16W 8N30W 11N42W...12N47W 10N57W. ISOLATED TO WIDELY
SCATTERED MODERATE SHOWERS AND THUNDERSTORMS FROM 10N TO 13N
BETWEEN 15W AND 18W...AND FROM 3N TO 10N BETWEEN 30W AND 53W.
SCATTERED STRONG SHOWERS AND THUNDERSTORMS FROM 8N TO 10N
BETWEEN 21W AND 24W.

...DISCUSSION...

THE GULF OF MEXICO...
MID/UPPER LEVEL LONGWAVE TROUGH EXTENDS OVER THE LOWER
MISSISSIPPI VALLEY TO THE EXTREME NW GULF ALONG THE TEXAS COAST.
WATER VAPOR IMAGERY INDICATES DRY AIR AND SUBSIDENCE RIGHT ALONG
THE IMMEDIATE COASTAL WATERS OF W LOUISIANA AND TEXAS...LIMITING
CONVECTION IN THESE AREAS. E OF THE UPPER TROUGH...BROAD
DIFFLUENCE COUPLED WITH A WEAK SURFACE LOW...1015...OVER SE
LOUISIANA CONTINUES TO TRIGGER CLOUDINESS AND WIDELY SCATTERED
SHOWERS/TSTMS OVER THE N GULF N OF ABOUT 24N. THE MOST NUMEROUS
AND STRONGEST OF THIS ACTIVITY CURRENTLY RESIDES OVER THE NE
GULF FROM THE WITHIN 100-200 NM EITHER SIDE OF A LINE FROM THE
FLORIDA BIG BEND AREA SW TO 24N90W.  FARTHER S...STORMINESS
CONTINUES OVER MUCH OF FLORIDA COURTESY OF A MID/UPPER LOW OVER
THE SE GULF AND A SURFACE TROUGH FROM W CUBA TO CENTRAL
FLORIDA.  BOTH FEATURES WILL TRANSITION SLOWLY WESTWARD DURING
THE NEXT 24 HOURS ALLOWING UNSETTLED/STORMY CONDITIONS TO
CONTINUE OVER THE E GULF AND FLORIDA THROUGH SUNDAY.
FINALLY...AN UPPER LEVEL LOW OVER THE SW GULF CENTERED 21N94W IS
DRIFTING W TOWARDS THE MEXICO COAST...WITH LITTLE CONVECTION
MAINLY DUE TO DRY AIR ALOFT.

THE CARIBBEAN SEA...
SHOWERS AND THUNDERSTORMS ARE IN THE ATLANTIC WATERS...JUST EAST
OF THE CARIBBEAN ISLANDS BETWEEN 55W AND 60W FROM 10N TO 20N
WITH THE 56W/57W TROPICAL WAVE. IT IS EASILY POSSIBLE THAT THIS
PRECIPITATION SHOULD REACH THE ISLANDS DURING THE NEXT 24 HOURS
AS THE WAVE MOVES WEST. SHOWERS AND THUNDERSTORMS ARE SEEN NEAR
PUERTO RICO AND NORTH OF IT...AND THE COLDEST CLOUD TOP
TEMPERATURES HAVE WARMED OVER HISPANIOLA...NEAR THE 24N70W 8N73W
TROPICAL WAVE. THE RIDGE WHICH WAS ALONG 90W FOR THE PAST DAY OR
SO HAS MOVED WESTWARD...NOW CLOSER TO THE ISTHMUS OF
TEHUANTEPEC. BROAD MIDDLE TO UPPER LEVEL CYCLONIC FLOW FROM A
RESULTANT TROUGH WHICH STRETCHES FROM EASTERN CUBA TO JAMAICA
TOWARD THE SOUTHWESTERN CORNER OF THE AREA.

THE ATLANTIC OCEAN...
SUBTROPICAL RIDGE IS CONFINED TO NW CORNER OF AREA AS THE
MID-OCEANIC TROUGH...COMPRISED OF A STRONG UPPER LOW NEAR
31N40W...CONTINUES ITS DOMINANCE OF THE E HALF OF THE ATLC.
SCATTERED SHOWERS/TSTMS HAVE BECOME MORE NUMEROUS NEAR THE COLD
CORE LOW WITH SCATTERED TO LOCALLY NUMEROUS ACTIVITY FROM
24N-32N BETWEEN 35W-47W.  OVER THE W ATLC...THE W EXTENT OF THE
MID-OCEANIC TROUGH HAS FRACTURED FORMING TWO RETROGRADING UPPER
LOWS...THE STRONGEST NEAR 26N68W...AND THE SECOND MOVING INTO
THE SE GLFMEX.  THESE TWO UPPER LOWS COMBINED WITH AMPLE
TROPICAL MOISTURE ASSOCIATED WITH TROPICAL WAVES HAVE PRODUCED
VERY STORMY CONDITIONS OVER MUCH OF THE W ATLC WATERS AND THE
BAHAMAS.  THE STRONGEST AND MOST NUMEROUS ACTIVITY IS CURRENTLY
LOCATED FROM PUERTO RICO AND HISPANIOLA NWD TO 25N BETWEEN 58W
AND THE TURKS/CAICOS.  THIS ACTIVITY WILL CONTINUE TO SPREAD
WEST-NORTHWESTWARD AROUND THE SW PERIPHERY OF THE W ATLC
SUBTROPICAL RIDGE SPREADING LOCALLY HEAVY RAINFALL AND GUSTY
WINDS OVER THE S BAHAMAS TONIGHT AND THE REMAINDER OF THE
BAHAMAS ON SUNDAY.

$$
MT


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