[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 010550
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED JUL 01 2009

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 29W/30W S OF 14N MOVING W 15-20 KT.
THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED
ON TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY ALSO
INDICATES CYCLONIC TURNING IN THE LOW-LEVEL CLOUD STRUCTURE S OF
9N. SCATTERED MODERATE CONVECTION IS W OF THE WAVE AXIS FROM
3N-7N BETWEEN 31W-33W. ALSO AN AREA OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS SLIGHTLY FARTHER WEST
ALONG THE ITCZ AXIS. WHILE NOT DIRECTLY ASSOCIATED WITH THE WAVE
THIS ACTIVITY IS MOST LIKELY BEING ENHANCED BY THE WAVE.

A TROPICAL WAVE IS ALONG 56W S OF 16N MOVING W NEAR 15 KT. THIS
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED ON
TOTAL PRECIPITABLE WATER IMAGERY AND CONTINUES ON THE LEADING
EDGE OF DUST AND A MIDDLE LAYER SAHARAN AIR LAYER TO THE W.
ISOLATED MODERATE CONVECTION IS OVER S AMERICA FROM 1N-5N
BETWEEN 56W-59W. THIS ACTIVITY IS BEING ENHANCED BY AN UPPER
LEVEL RIDGE CENTERED OVER THE FAR SE CARIBBEAN.

A TROPICAL WAVE IS ALONG 93W/94W S OF 17N MOVING W NEAR 18 KT.
THE WAVE REMAINS MORE PROMINENT IN THE E PACIFIC REGION...REFER
TO THE TWDEP FOR MORE DETAILS.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 15N11W 9N18W 7N28W 5N41W AND
INTO NE S AMERICA NEAR 5N53W. NUMEROUS MODERATE/ SCATTERED
STRONG CONVECTION IS JUST OFF THE COAST OF AFRICA FROM 8N-12N
BETWEEN 14W-18W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 4N-7N BETWEEN 34W-38W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT IS ACROSS THE NRN GULF EXTENDING FROM THE W
ATLC ACROSS N FLORIDA ENTERING THE GULF WATERS NEAR 30N84W
EXTENDING TO NEAR NEW ORLEANS LOUISIANA NEAR 29N92W. THE FRONT
IS LOCATED UNDER THE BASE OF AN UPPER LEVEL TROUGH OVER THE ERN
UNITED STATES. UPPER LEVEL SUPPORT FROM THE TROUGH ALONG WITH
SURFACE CONVERGENCE NEAR THE FRONT ARE SUPPORTING ISOLATED
SHOWERS/POSSIBLE THUNDERSTORMS ACROSS THE E GULF FROM 24N-29N E
OF 86W TO OVER THE FLORIDA PENINSULA AND INTO THE W ATLC. A
SURFACE TROUGH ACROSS THE YUCATAN PENINSULA INTO THE CENTRAL
GULF EXTENDS FROM 18N91W TO 26N87W. SURFACE CONVERGENCE NEAR THE
TROUGH ALONG WITH UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL
HIGH OVER SRN MEXICO NEAR 18N100W AND AN UPPER LEVEL LOW OVER
THE CENTRAL CARIBBEAN NEAR 17N77W ARE SUPPORTING NUMEROUS
SHOWERS AND THUNDERSTORMS OVER THE YUCATAN PENINSULA AND THE
ADJACENT COASTAL WATERS S OF 22N BETWEEN 87W-91W. THESE FEATURES
ARE ALSO SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS OVER S
FLORIDA AND THE STRAITS OF FLORIDA S OF 26N E OF 82W. THE
REMAINDER OF THE GULF OF MEXICO REMAINS UNDER A WEAK RIDGE
PROVIDING FAIR WEATHER AND LIGHT WINDS UP TO 15 KT.

CARIBBEAN SEA...
A BROAD UPPER LEVEL LOW CENTERED NEAR 17N77W DOMINATES THE
CENTRAL AND WRN CARIBBEAN WHILE AN UPPER LEVEL HIGH IS OVER THE
FAR SE CARIBBEAN NEAR 12N63W DOMINATING THE ERN CARIBBEAN AND
THE LESSER ANTILLES. MOIST SWLY FLOW ALOFT BETWEEN THESE UPPER
LEVEL FEATURES IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS
OVER THE S CENTRAL CARIBBEAN S OF 14N BETWEEN 67W-75W. SURFACE
CONVERGENCE NEAR A SURFACE LOW OVER COLUMBIA NEAR 9N74W IS ALSO
SUPPORTING THE SHOWER ACTIVITY OVER THE S CENTRAL CARIBBEAN.
UPPER LEVEL DIFFLUENCE AT THE BASE OF THE UPPER LEVEL TROUGH
OVER THE WRN AND CENTRAL CARIBBEAN IS ALSO SUPPORTING A LINE OF
SHOWERS/THUNDERSTORMS FROM 11N79W TO 14N83W. THE UPPER LEVEL
HIGH OVER THE ERN CARIBBEAN IS ALSO SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS OVER THE FAR SE CARIBBEAN FROM 11N-14N E
OF 63W AND INTO THE ATLC. THIS ACTIVITY IS PROBABLY BEING
ENHANCED BY THE TROPICAL WAVE E OF THE LESSER ANTILLES. ELY
TRADE WINDS OF UP TO 20 KT COVER THE MAJORITY OF THE CARIBBEAN
BRINING ISOLATED SHOWERS MAINLY OVER THE NE CARIBBEAN.

ATLANTIC OCEAN...
A SMALL PIECE OF A DISSIPATING STATIONARY FRONT ENTERS THE W
ATLC DISCUSSION AREA NEAR 30N81W AND CONTINUES TO 31N80W. MOIST
WLY FLOW ALOFT AROUND A BROAD UPPER LEVEL HIGH OVER THE W ATLC
NEAR 27N72W AND UPPER LEVEL DIFFLUENCE AT THE BASE OF AN UPPER
LEVEL TROUGH OVER THE ERN UNITED STATES ARE SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE FLORIDA PENINSULA...THE NW
BAHAMAS AND THE WRN ATLC N OF 24N BETWEEN 64W-81W. UPPER LEVEL
DIFFLUENCE BETWEEN THE BROAD UPPER LEVEL RIDGE OVER THE W ATLC
AND AN UPPER LEVEL TROUGH COVERING THE E ATLC IS SUPPORTING A
SMALL AREA OF SCATTERED SHOWERS IN THE CENTRAL ATLC FROM 26N-29N
BETWEEN 35W-38W. THE REMAINDER OF THE ATLC IS UNDER A BROAD
SURFACE RIDGE ANCHORED BY A PAIR OF SURFACE HIGHS...A 1021 MB
HIGH CENTERED NEAR 26N52W AND A 1023 MB HIGH NEAR 28N38W. A
BROAD AREA OF AFRICAN DUST COVERS THE ERN TROPICAL ATLC S OF 26N
TO THE ITCZ E OF 50W.

$$
WALTON




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