[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 151753
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 15 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 10N18W TO 16N20W TO 22N19W MOVING W
AT 15-20 KT. THE WAVE LIES ON THE LEADING EDGE OF MAXIMUM TOTAL
PRECIPITABLE WATER VALUES BEGINNING TO EMERGE OFF OF THE W
AFRICA COAST AND ALSO IS EMBEDDED WITHIN A BROAD LOW-LEVEL
CYCLONIC GYRE S OF 22N BETWEEN 15W-35W. A 1011 MB LOW IS LOCATED
WEST OF THE WAVE CENTERED NEAR 17N22W THAT IS FORECAST TO DRIFT
SW OVER THE NEXT 24 HOURS. WHILE THE WAVE COINCIDES WITH A
600-700 MB TROUGH AXIS...IT REMAINS SHROUDED IN THE SAHARAN AIR
LAYER AND THEREFORE CONVECTION IS CONFINED TO THE AREA NEAR THE
ITCZ AXIS. SCATTERED MODERATE CONVECTION IS FROM 07N-14N BETWEEN
14W-22W.

TROPICAL WAVE EXTENDS FROM 08N51W TO 13N56W TO 19N58W MOVING W
AT 15-20 KT. THE WAVE REMAINS EMBEDDED WITHIN A WEAK CYCLONIC
LOW-LEVEL PERTURBATION THAT ALSO FOLLOWS ON THE LEADING EDGE OF
AN EXTENSIVE SAHARAN AIR LAYER THAT STRETCHES EASTWARD FROM THE
WAVE AXIS TO 30W. SCATTERED MODERATE CONVECTION IS APPROACHING
THE LESSER ANTILLES AND IS LOCATED FROM 11N-18N BETWEEN 58W-60W.
AN AREA OF ISOLATED MODERATE CONVECTION IS LOCATED EAST OF THE
WAVE FROM 13N-17N BETWEEN 51W-56W.

TROPICAL WAVE IS ALONG 76W S OF 18N MOVING W AT 15-20 KT. GLOBAL
MODEL GUIDANCE INDICATES WEAK LOW-LEVEL CYCLONIC CURVATURE IN
THE VICINITY OF THE WAVE AXIS AND IS OBSERVED ON LATEST VISIBLE
SATELLITE IMAGERY. DEEP TROPICAL MOISTURE IS NOTED ON TOTAL
PRECIPITABLE WATER IMAGERY WEST OF THE WAVE AXIS THAT CONTINUES
TO AID IN GENERATING SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION FROM 14N-18N BETWEEN 70W-84W.

TROPICAL WAVE IS ALONG 95W S OF 21N MOVING W AT 10-15 KT. THE
WAVE EXTENDS INTO THE E PACIFIC REGION THROUGH THE ISTHMUS OF
TEHUANTEPEC GENERATING SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION S OF 17N OVER SOUTHERN MEXICO.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 11N19W 08N32W 09N48W 07N53W 10N74W.
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM
05N-11N BETWEEN 20W-40W. SIMILAR CONVECTION IS FROM 07N-10N
BETWEEN 55W-59W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONE COVERS MUCH OF THE GULF E OF 96W THAT
REMAINS CENTERED OVER LOUISIANA. OVERALL...THIS UPPER LEVEL
RIDGE IS SUPPORTING A SURFACE RIDGE ORIENTED SE TO NW FROM CUBA
TO THE TEXAS/LOUISIANA BORDER NEAR 30N94W AND IS ANCHORED BY A
1016 MB HIGH CENTERED IN THE E GULF NEAR 26N86W. LIGHT E-SE
WINDS ARE LOCATED SW OF THE RIDGE AXIS WITH GENERALLY FAIR SKIES
NOTED ON VISIBLE SATELLITE IMAGERY THIS AFTERNOON S OF 27N AND W
OF 93W. HOWEVER...OVER THE NE GULF...A SURFACE TROUGH EXTENDS
FROM A 1013 MB LOW CENTERED OVER SE ALABAMA TO PANAMA CITY
FLORIDA AND INTO THE NORTH-CENTRAL GULF NEAR 29N90W. MOSAIC
DOPPLER RADAR AND LIGHTNING DATA INDICATE NUMEROUS SHOWERS AND
SCATTERED TSTMS N OF 27N BETWEEN 84W-92W. THE SURFACE LOW IS
FORECAST TO MOVE SW AND EMERGE OUT INTO THE FAR NORTH-CENTRAL
GULF WATERS OVER THE NEXT 12-24 HOURS ON THE NORTHEASTERLY UPPER
LEVEL STEERING FLOW ASSOCIATED WITH THE UPPER LEVEL ANTICYCLONE
CENTERED OVER LOUISIANA. SW TO W WINDS INCREASING TO 20 KT BY
MONDAY AFTERNOON OVER THE MIDDLE GULF.

CARIBBEAN SEA...
THE CARIBBEAN NW OF A LINE FROM HISPANIOLA TO PANAMA IS UNDER
THE INFLUENCE OF UPPER LEVEL NE FLOW ON THE SOUTHERN PERIPHERY
OF A LARGE ANTICYCLONIC CENTERED OVER THE SE CONUS. UPPER LEVEL
MOISTURE AND CLOUDINESS CONTINUES TO ADVECT SW FROM THE
BAHAMAS...ACROSS CUBA...AND THE NW CARIBBEAN. LOW-LEVEL
CONVERGENCE OF THE EASTERLY TRADES AND ATMOSPHERIC INSTABILITY
ARE GENERATING SCATTERED SHOWERS AND TSTMS OVER THE CARIBBEAN N
OF 13N W OF 74W. A TROPICAL WAVE ALONG 76W IS ALSO PROVIDING
LOW-LEVEL FOCUS FOR THIS CONVECTIVE ACTIVITY AS IT MOVES
WESTWARD. ELSEWHERE...AN UPPER LEVEL TROUGH EXTENDS FROM THE SW
NORTH ATLC NEAR 21N67W TO AN UPPER LEVEL LOW CENTERED NEAR
14N73W THAT IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS N
OF 14N BETWEEN 65W-74W. THIS INCLUDES PUERTO RICO...THE MONA
PASSAGE...AND HISPANIOLA. WITH THE APPROACH OF THE TROPICAL WAVE
ALONG 57W...THE LESSER ANTILLES ARE FORECAST TO SEE AN INCREASE
IN LOW-LEVEL MOISTURE...SCATTERED SHOWERS...AND ISOLATED TSTMS
OVER THE NEXT 24-36 HOURS.

ATLANTIC OCEAN...
THE UPPER LEVEL ANTICYCLONE LOCATED OVER THE SE CONUS EXTENDS
EASTWARD TO 70W PROVIDING MUCH OF THE W ATLC WITH NE UPPER LEVEL
FLOW. TO THE EAST...AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG
32N63W TO 27N68W AND SUPPORTS A STATIONARY FRONT ANALYZED ALONG
32N59W 27N70W 30N78W TO THE GEORGIA COAST NEAR 31N81W. SCATTERED
SHOWERS AND ISOLATED TSTMS ARE WITHIN 150 NM SE OF THE FRONT E
OF 70W...FROM 19N-27N BETWEEN 70W-77W. SCATTERED SHOWERS AND
TSTMS ARE OCCURRING SOUTH OF THE FRONT WHERE HIGHER INSTABILITY
IS LOCATED FROM 22N-32N BETWEEN 77W-81W. FARTHER EAST...THE
REMAINDER OF THE ATLC IS UNDER GENERALLY FAIR CONDITIONS DUE TO
A SURFACE RIDGE ANCHORED BY A 1029 MB HIGH CENTERED OVER THE
AZORES NEAR 39N28W. THE SURFACE RIDGE AXIS EXTENDS FROM THE HIGH
SW ALONG 32N40W TO ANGUILLA NEAR 19N63W. VISIBLE SATELLITE
IMAGERY ALSO INDICATES A LARGE AREA OF SAHARAN DUST THAT COVERS
THE EASTERN ATLC FROM 12N-33N BETWEEN 35W-52W...AND FROM 10N-25N
E OF 35W TO THE W AFRICA COAST.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN




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