[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN JUL 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 22W S OF 15N MOVING W 15-20 KT. THE
WAVE COINCIDES WITH AN 850 MB RELATIVE VORTICITY MAXIMUM SEEN ON
THE CIMSS WAVETRAK PRODUCT AS WELL AS A DEEP LAYER MOISTURE
MAXIMUM OBSERVED ON TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED
MODERATE CONVECTION IS FROM 8N-13N BETWEEN 19W-26W.

A TROPICAL WAVE EXTENDS FROM 18N47W TO 3N43W MOVING W 15-20 KT.
SATELLITE IMAGERY INDICATES BROAD CYCLONIC FLOW AROUND THE
VICINITY OF THE WAVE. THIS WAVE ALSO COINCIDES WITH A DEEP LAYER
MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY.
DEEP CONVECTION IS LIMITED DUE TO THE VICINITY OF A MID-LEVEL
LAYER OF SAHARAN DRY AIR. ISOLATED MODERATE CONVECTION IS FROM
6N-8N BETWEEN 42W-44W.

A TROPICAL WAVE IS OVER THE W CARIBBEAN AND CENTRAL AMERICA
ALONG 83W/84W S OF 20N MOVING W 20-25 KT. A MOISTURE MAXIMUM IN
TOTAL PRECIPITABLE WATER IMAGERY IS APPARENT ON SATELLITE
IMAGERY. CONVECTION IS PRIMARILY W OF THE WAVE AXIS AND IS BEING
ENHANCED BY UPPER LEVEL DIFFLUENCE. SCATTERED MODERATE
CONVECTION IS FROM 11N-19N BETWEEN 82W-87W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N16W 11N23W 6N30W 8N45W AND
INTO S AMERICA NEAR 6N54W. BESIDES THE CONVECTION MENTIONED IN
THE TROPICAL WAVE SECTION...NUMEROUS STRONG CONVECTION IS ALONG
THE COAST OF W AFRICA FROM 11N-16N BETWEEN 14W-18W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 4N-8N BETWEEN 25W-33W.

...DISCUSSION...

GULF OF MEXICO...
A 1022 MB HIGH IS OVER THE NE GULF OF MEXICO NEAR 28N87W. A
RIDGE AXIS CONTINUES W TO THE TEXAS COAST NEAR 29N95W. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER THE N GULF
STATES FROM 30N-32N BETWEEN 87W-92W. ISOLATED MODERATE
CONVECTION IS ALSO OVER THE SOUTHERN BAY OF CAMPECHE S OF 20N.
MOST OF THE REMAINDER OF THE GULF HAS PARTLY CLOUDY SKIES WITH
5-10 KT ANTICYCLONIC WINDS. IN THE UPPER LEVELS...A LARGE HIGH
IS CENTERED OVER CENTRAL TEXAS PRODUCING PREDOMINATELY NE
UPPER LEVEL FLOW OVER THE GULF N OF 23N. AN UPPER LEVEL LOW IS
ALSO CENTERED OVER S MEXICO NEAR 19N100W MOVING W. STRONG
SUBSIDENCE IS NOTED OVER TEXAS AND THE CENTRAL GULF FROM
23N-27N. UPPER LEVEL MOISTURE IS OVER THE NE GULF...THE YUCATAN
PENINSULA... AND THE BAY OF CAMPECHE. EXPECT...CONTINUED
CONVECTION OVER THE NE GULF AND THE BAY OF CAMPECHE OVER THE
NEXT 24 HOURS.

CARIBBEAN SEA...
A TROPICAL WAVE OVER THE WESTERN CARIBBEAN IS THE MAIN WEATHER
FEATURE IN THE CARIBBEAN. SEE ABOVE. ISOLATED MODERATE
CONVECTION IS OVER THE YUCATAN PENINSULA FROM 18N-21N BETWEEN
87W-92W. FURTHER E...STRONG TRADEWINDS TOGETHER WITH UPPER LEVEL
DIFFLUENCE FROM AN UPPER LEVEL LOW CENTERED OVER THE SOUTHERN
BAHAMAS IS PRODUCING SCATTERED MODERATE CONVECTION OVER THE
HIGHER ELEVATIONS OF HISPANIOLA AND CUBA. IN THE UPPER LEVELS...
AN UPPER LEVEL HIGH IS CENTERED OVER THE W CARIBBEAN NEAR
13N80W. ANOTHER UPPER LEVEL HIGH IS CENTERED OVER THE E
CARIBBEAN NEAR 13N62W. EXPECT...THE TROPICAL WAVE TO PRODUCE
CONTINUED CONVECTION OVER CENTRAL AMERICA OVER THE NEXT 24
HOURS. ALSO EXPECT MORE CONVECTION OVER CUBA.

ATLANTIC OCEAN...
A SURFACE TROUGH IS OVER THE W ATLANTIC ALONG 28N64W 23N67W.
SCATTERED SHOWERS ARE WITHIN 30 NM OF THE TROUGH AXIS. FURTHER
E...ANOTHER SURFACE TROUGH IS ALONG 25N58W 19N60W WITH SCATTERED
SHOWERS. THE TAIL END OF A COLD FRONT IS OVER THE CENTRAL
ATLANTIC ALONG 32N34W 29N38W 29N42W. SCATTERED SHOWERS ARE ALSO
WITHIN 60 NM E OF FRONT. IN THE UPPER LEVELS...AN UPPER LEVEL
LOW IS CENTERED OVER THE S BAHAMAS NEAR 22N72W. ANOTHER UPPER
LEVEL LOW IS OVER THE CENTRAL ATLANTIC NEAR 28N54W. AN UPPER
LEVEL HIGH IS OVER THE E ATLANTIC NEAR 22N33W. AN UPPER LEVEL
LOW IS ALSO N OF THE CANARY ISLANDS NEAR 32N18W.
EXPECT...CONVECTION OVER THE NEXT 24 HOURS WITH THE ATLANTIC
TROPICAL WAVES...SURFACE TROUGHS...AND FRONTAL SYSTEM.

$$
FORMOSA




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