[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 072359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 07 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC...

...SPECIAL FEATURES...

A 1007 MB LOW IS CENTERED IN THE WESTERN GULF OF MEXICO NEAR
24N94W AND EXTENDS A SURFACE TROUGH FROM THE LOW TO THE TEXAS
COAST NEAR FREEPORT...OR 29N95W. THIS EVENING THE SYSTEM
CONTINUES TO ORGANIZE WITH SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION LOCATED FROM 20N-27N BETWEEN 91W-97W. MAXIMUM
DAYTIME HEATING AND INSTABILITY HAVE ALSO GENERATED SCATTERED
STRONG CONVECTION FARTHER SE AWAY FROM THE LOW-LEVEL CIRCULATION
CENTER OVER THE WESTERN YUCATAN PENINSULA FROM 17N-22N BETWEEN
88W-92W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ELSEWHERE OVER
THE WESTERN GULF W OF 88W AND STRETCH INLAND OVER LOUISIANA AND
EASTERN TEXAS. WITH THE LOW FORECAST TO TRACK NW OVER THE NEXT
24-36 HOURS...UPPER LEVEL WIND SHEAR VALUES REMAIN LOW AND UPPER
LEVEL DIVERGENCE REMAINS HIGH OVER MUCH OF THE WESTERN GULF...
PROVIDING THE SYSTEM WITH A FAVORABLE ENVIRONMENT FOR
DEVELOPMENT.

...TROPICAL WAVES...

TROPICAL WAVE IS FROM 04N15N ALONG 16W MOVING W AT 10-15 KT.
UPPER AIR TIME-SECTION ANALYSES FROM DAKAR SENEGAL INDICATES A
DEEP LAYER WAVE THAT IS VERY CLOSE TO PASSING THE STATION IN
DAKAR. TOTAL PRECIPITABLE WATER IMAGERY AND GLOBAL MODEL
GUIDANCE ALSO INDICATES A NORTHERN LOW-LEVEL VORTICITY MAXIMUM
HAS EMERGED OFF THE W AFRICA COAST AND IS LOCATED WEST OF THE
AXIS NEAR 12N20W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 05N-10N BETWEEN 12W-20W.

TROPICAL WAVE EXTENDS FROM 18N42W TO 04N45W MOVING W AT 15-20
KT. BROAD LOW-LEVEL CYCLONIC FLOW IS NEAR THE WAVE AXIS EVIDENT
IN SATELLITE IMAGERY AND ALSO LIES WITHIN A DEEP LAYER MOISTURE
MAXIMUM INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY BETWEEN
35W-43W. CONVECTION REMAINS SOMEWHAT LIMITED WITH THE WAVE DUE
TO A SAHARAN AIR LAYER EAST OF THE WAVE AXIS TO THE W AFRICA
COAST...HOWEVER ISOLATED MODERATE CONVECTION IS FROM 09N-14N
BETWEEN 43W-50W...AND SCATTERED SHOWERS ARE WITHIN 120 NM EITHER
SIDE OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 12N55W TO 06N60W MOVING W AT 10-15
KT. CYCLONIC LOW-LEVEL FLOW IS ABOUT THE WAVE AXIS INDICATED BY
SATELLITE IMAGERY AND AN EARLIER WINDSAT SCATTEROMETER PASS. THE
WAVE ALSO LIES WITHIN AN AREA OF DEEP LAYER MOISTURE S OF 13N
BETWEEN 55W-63W. SCATTERED MODERATE CONVECTION IS FROM 08N-12N
BETWEEN 54W-64W.

TROPICAL WAVE EXTENDS FROM EASTERN CUBA NEAR 20N75W TO NORTHERN
COLOMBIA NEAR 10N75W MOVING W AT 15 KT. THE WAVE CONTINUES TO BE
ASSOCIATED WITH AN AREA OF MAXIMUM TOTAL PRECIPITABLE WATER
ADVECTING ACROSS THE CENTRAL CARIBBEAN SEA WITH SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION FROM 15N-22N BETWEEN
73W-78W. ISOLATED MODERATE TO STRONG CONVECTION IS ALSO FROM
10N-21N BETWEEN 73W-76W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 08N18W 05N30W 05N43W 08N57W.
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM
01N-06N BETWEEN 25W-30W...AND FROM THE EQUATOR TO 06N BETWEEN
35W-43W.

...DISCUSSION...

GULF OF MEXICO...
SIGNIFICANT DEEP LAYER MOISTURE CONTINUES TO IMPACT THE WESTERN
GULF DUE TO AN AREA OF LOW PRESSURE CENTERED NEAR 24N94W. A
SURFACE TROUGH EXTENDS NORTHWARD TO THE TEXAS COAST NEAR
FREEPORT WITH SCATTERED SHOWERS AND ISOLATED TSTMS COVERING MUCH
OF THE WESTERN GULF W OF 88W. EAST OF THE SURFACE TROUGH...A
STRONG PRESSURE GRADIENT EXISTS IN THE NE QUADRANT OF THE LOW N
OF 24N BETWEEN 87W-94W ENHANCING SE WINDS OVER THE BASIN.
ALOFT...AN UPPER LEVEL LOW IS CENTERED NEAR 25N97W AND CONTINUES
TO SUPPORT THE BROAD SURFACE LOW PRESSURE TO THE SE. WEAK UPPER
LEVEL RIDGING COVERS THE NORTH-CENTRAL GULF WITH A NARROW UPPER
LEVEL RIDGE AXIS EXTENDING FROM LOUISIANA TO 24N90W. ELSEWHERE
THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A SURFACE
RIDGE EXTENDING SOUTH TO 27N FROM THE SE CONUS. GENERALLY FAIR
WEATHER AND CLEAR SKIES ARE ASSOCIATED WITH THE SURFACE RIDGE...
HOWEVER...A FEW ISOLATED SHOWERS AND TSTMS ARE EMBEDDED WITHIN
EASTERLY FLOW OVER THE SE GULF AND SOUTHERN FLORIDA PENINSULA
THIS EVENING FROM 24N-27N E OF 84W.

CARIBBEAN SEA...
UPPER LEVEL TROUGHING RESIDES ACROSS MUCH OF THE WESTERN
CARIBBEAN AS AN EXTENSION OF AN UPPER LEVEL LOW LOCATED OVER THE
SW NORTH ATLC. THE UPPER LEVEL TROUGH AXIS EXTENDS ACROSS
EASTERN CUBA AND DIPS SOUTHWARD TO THE SW CARIBBEAN NEAR 12N79W.
EVEN THOUGH MOSTLY NORTHERLY FLOW IS NOTED ON WATER VAPOR
IMAGERY WEST OF THE TROUGH AXIS...LOW-LEVEL SOUTHEASTERLY FLOW
CONTINUES TO ADVECT MOISTURE NW INTO THE SURFACE CIRCULATION
LOCATED IN THE WESTERN GULF OF MEXICO WITH ISOLATED SHOWERS
POSSIBLE W OF 80W. A TROPICAL WAVE EXTENDS ACROSS THE CENTRAL
CARIBBEAN FROM EASTERN CUBA TO NORTHERN COLOMBIA AND CONTINUES
TO ENHANCE SCATTERED SHOWERS AND TSTMS FROM 15N-22N BETWEEN
73W-78W. MAXIMUM DAYTIME HEATING AND INSTABILITY IS ALSO
GENERATING SCATTERED SHOWERS AND TSTMS OVER CUBA AND HISPANIOLA
THIS EVENING. THE REMAINDER OF THE CARIBBEAN IS UNDER GENERALLY
CLEAR SKIES DUE TO AN UPPER LEVEL RIDGE COVERING THE EASTERN
CARIBBEAN. THE UPPER LEVEL RIDGE AXIS EXTENDS ALONG 12N TO 73W
FROM AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 12N61W.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS LOCATED N OF THE DISCUSSION AREA CENTERED
NEAR 33N70W WITH AN UPPER LEVEL TROUGH AXIS EXTENDING SOUTHWARD
TO THE CENTRAL BAHAMAS AND OVER CENTRAL CUBA. THIS UPPER LEVEL
TROUGHING SUPPORTS TWO AREAS OF LOW-LEVEL TROUGHING ACROSS THE W
ATLC. THE FIRST IS A SURFACE TROUGH ANALYZED FROM 23N-27N ALONG
78W THAT IS IMPACTING THE NW BAHAMAS WITH SCATTERED SHOWERS AND
ISOLATED TSTMS FROM 23N-28N BETWEEN 74W-80W. FARTHER EAST...
ANOTHER SURFACE TROUGH EXTENDS INTO THE DISCUSSION AREA NEAR
32N70W TRAILING SOUTHWARD INTO A WEAK 1014 MB LOW NEAR 27N71W
THEN CONTINUING SOUTH TO THE CAICOS ISLANDS NEAR 22N72W.
SCATTERED SHOWERS AND TSTMS ARE EAST OF THIS SURFACE TROUGH
COVERING THE AREA FROM 22N-30N BETWEEN 62W-70W. FARTHER EAST...
A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1028 MB HIGH
CENTERED NEAR 35N44W PROVIDING FOR GENERALLY FAIR CONDITIONS
THIS EVENING OVER THE CENTRAL AND EASTERN ATLC. HOWEVER...A
SURFACE TROUGH EXTENDS FROM 31N49W TO 24N52W. POSSIBLE ISOLATED
SHOWERS ARE WITHIN 200 NM EAST OF THE TROUGH AXIS. ALOFT...AN
UPPER LEVEL LOW IS CENTERED NEAR 25N49W THAT EXTENDS TROUGHING
TO 15N BETWEEN 45W-60W. EAST OF THE UPPER LEVEL LOW IS AN
ANTICYCLONIC CIRCULATION CENTERED NEAR 19N36W THAT ENCOMPASSES
THE EASTERN ATLC E OF 42W.

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

$$
HUFFMAN



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