[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED JUL 28 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS IN THE CENTRAL ATLC ALONG 17N34W 12N40W 5N44W
MOVING W 15-20 KT. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS
INDICATE BROAD CYCLONIC FLOW ABOUT THE WAVE AXIS. THE WAVE ALSO
LIES EMBEDDED IN A DEEP LAYER MOISTURE MAXIMUM EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 6N-9N BETWEEN 38W-43W. CLUSTERS OF
MODERATE/STRONG CONVECTION ARE ALSO FROM 14N-16N BETWEEN 41W-44W.

TROPICAL WAVE IS ACROSS THE LESSER ANTILLES ALONG 18N58W TO
8N63W MOVING W NEAR 12 KT. UPPER AIR SOUNDINGS FROM BARBADOS
INDICATE A SURGE OF MOISTURE AROUND 28/0000 UTC. THIS MOISTURE
SURGE BEHIND THE WAVE AXIS IS ALSO PRESENT IN TOTAL PRECIPITABLE
WATER IMAGERY. ISOLATED MODERATE/STRONG CONVECTION IS ALONG THE
WAVE AXIS FROM 12N-14N.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 12N25W 13N38W 8N50W
7N60W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS OFF THE
COAST OF AFRICA FROM 7N-11N BETWEEN 10W-16W. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 8N-11N BETWEEN 18W-25W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-9N
BETWEEN 31W-36W. SIMILAR ACTIVITY IS FROM 6N-10N BETWEEN 50W-56W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH PARALLELS THE SE MEXICAN COASTLINE ALONG 24N97W
TO 18N94W IN THE SW GULF OF MEXICO ENHANCING SCATTERED
SHOWERS/THUNDERSTORMS FROM 22N-25N BETWEEN 95W-97W. NUMEROUS
STRONG CONVECTION IS ALSO FROM 17N-20N BETWEEN 93W-96W. THESE
AREAS OF CONVECTION ARE FURTHER SUPPORTED BY DIFFLUENCE ALOFT
BETWEEN AN UPPER LEVEL TROUGH OVER THE SW GULF AND AN UPPER
LEVEL RIDGE OVER S CENTRAL MEXICO. AN UPPER LEVEL LOW OVER N
CENTRAL TEXAS IS ALSO SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS
OVER THE NW GULF INDICATED BY RADAR DATA. THE REMAINDER OF THE
BASIN IS DOMINATED BY SURFACE RIDGING ANCHORED BY A 1020 MB HIGH
S OF MOBILE ALABAMA NEAR 28N89W MAINTAINING FAIR CONDITIONS AND
CLEAR SKIES. ALOFT...ANOTHER BROAD UPPER LEVEL LOW IS SPINNING
ACROSS THE N CENTRAL GULF SUPPORTING A FEW HIGH CLOUDS. EXPECT
THE SURFACE RIDGE TO GRADUALLY SHIFT WWD SUPPORTING GENERALLY
FAIR WEATHER ACROSS THE BASIN.

CARIBBEAN SEA...
A TIGHT PRESSURE GRADIENT BETWEEN SURFACE RIDING ACROSS THE ATLC
AND LOWER PRESSURES ACROSS NRN SOUTH AMERICA IS MAINTAINING
STRONG TRADEWINDS ACROSS MUCH OF THE BASIN. DRY AIR ALOFT AROUND
AN UPPER LEVEL TROUGH CENTERED S OF JAMAICA IS PROVIDING CLEAR
SKIES OVER THE AREA. HOWEVER...DIFFLUENCE AROUND THE BASE OF THE
UPPER TROUGH IN COMBINATION WITH SURFACE CONVERGENCE NEAR AN
EXTENSION OF THE E PACIFIC ITCZ ACROSS COSTA RICA TO COLOMBIA IS
ENHANCING SCATTERED STRONG CONVECTION S OF 12N BETWEEN 73W-83W.
A TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES SUPPORTING
ISOLATED MODERATE CONVECTION FROM 12N-15N BETWEEN 60W-62W AS
WELL AS INLAND OVER VENEZUELA. ELSEWHERE ALOFT...UPPER LEVEL
RIDGING COVERS THE ERN CARIBBEAN CENTERED E OF THE LESSER
ANTILLES NEAR 14N57W. EXPECT MOSTLY DRY CONDITIONS ACROSS MUCH
OF THE BASIN WITH SHOWERS/THUNDERSTORMS IN THE E CARIBBEAN AS
THE TROPICAL WAVE PROGRESSES WWD.

ATLANTIC OCEAN...
SURFACE RIDGING ANCHORED BY A 1020 MB HIGH N OF THE BAHAMAS NEAR
27N75W IS MAINTAINING FAIR CONDITIONS ACROSS THE W ATLC
SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED OFF THE COAST OF
SOUTH CAROLINA NEAR 31N75W. AN UPPER LEVEL TROUGH TO THE N OF
THE UPPER RIDGE IS SUPPORTING A COLD FRONT PUSHING INTO THE
DISCUSSION AREA ALONG 32N60W 30N69W 32N78W. ISOLATED
SHOWERS/THUNDERSTORMS ARE WITHIN 60 NM EITHER SIDE OF THE FRONT.
THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING
AROUND A 1025 MB HIGH NEAR 30N39W PROVIDING FAIR WEATHER ACROSS
THE AREA. ALOFT...A NARROW UPPER LEVEL TROUGH EXTENDS FROM
31N52W TO N OF PUERTO RICO. AN UPPER LEVEL RIDGE IS CENTERED E
OF THE LESSER ANTILLES NEAR 14N57W WITH A BROAD UPPER LEVEL
TROUGH TO ITS E ALONG 19N47W TO EQ33W. UPPER LEVEL RIDGING
COVERS THE E ATLC CENTERED BETWEEN THE CAPE VERDE ISLANDS AND
THE CANARY ISLANDS.

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

$$
WALTON





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