000 AXNT20 KNHC 160003 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUL 15 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 26W S OF 15N MOVING W NEAR 15 KT. SATELLITE IMAGERY SHOWS SOME MID-LEVEL CYCLONIC FLOW IN THE VICINITY OF THIS WAVE. THIS WAVE ALSO COINCIDES WITH A LOW AMPLITUDE DEEP LAYER MOISTURE MAXIMUM OBSERVED ON TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE CONVECTION IS FROM 6N-12N BETWEEN 24W-29W. A TROPICAL WAVE IS ALONG 42W/43W S OF 16N MOVING W NEAR 15 KT. THIS WAVE COINCIDES WITH A LOW AMPLITUDE DEEP LAYER MOISTURE MAXIMUM OBSERVED ON TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THIS WAVE. A HIGHLY-AMPLIFIED TROPICAL WAVE IS OVER THE SW NORTH ATLC AND E CARIBBEAN EXTENDING FROM 24N69W TO 16N71W TO 8N70W MOVING W NEAR 20 KT. SATELLITE IMAGERY SHOWS A WELL-DEFINED AND HIGHLY AMPLIFIED INVERTED-V PATTERN IN THE LOW-LEVEL CLOUDS NEAR THE WAVE. THE WAVE ALSO COINCIDES WITH A HIGH AMPLITUDE MOISTURE MAXIMUM IN TOTAL PRECIPITABLE WATER. THE WAVE IS AT THE LEADING EDGE OF AN ABUNDANT DRY LOW/MID-LEVEL SAHARAN AIR LAYER. THE DRY AIR...ALONG WITH STABLE ATMOSPHERIC CONDITIONS BENEATH AN UPPER LEVEL HIGH OVER THE E CARIBBEAN...ARE LIMITING DEEP CONVECTION NEAR THE WAVE. HOWEVER...SCATTERED SHOWERS ARE WITHIN 100 NM OF THE WAVE AXIS FROM 18N-21N. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 11N26W 9N35W 11N43W 9N50W 9N61W. BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE ABOVE...SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF WEST AFRICA FROM 8N-12N E OF 16W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH IS OVER THE NORTH CENTRAL GULF OF MEXICO ALONG 30N89W 27N92W 26N95W. WIDELY SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF LOUISIANA FROM 27N-32N BETWEEN 90W-94W. HIGH PRESSURE RIDGING EXTENDS FROM THE ATLANTIC TO THE E GULF OF MEXICO. PATCHES OF WIDELY SCATTERED MODERATE CONVECTION IS OVER FLORIDA. SIMILAR CONVECTION IS OVER THE YUCATAN PENINSULA FROM 16N-21N BETWEEN 88W-91W. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER ALABAMA PRODUCING MOSTLY NE UPPER LEVEL FLOW OVER THE GULF OF MEXICO. AREAS OF UPPER LEVEL MOISTURE ARE NOTED OVER THE E GULF E OF 93W. STRONG SUBSIDENCE IS OVER THE W GULF AND TEXAS. EXPECT MORE CONVECTION OVER THE N GULF N OF 25N ...AND OVER THE BAY OF CAMPECHE OVER THE NEXT 24 HOURS. CARIBBEAN SEA... FRESH TO STRONG TRADEWINDS ARE OVER THE CARIBBEAN SEA WITH THE STRONGEST FLOW NEAR THE COAST OF COLOMBIA WHERE GALE CONDITIONS ARE FORECAST TO BEGIN TONIGHT. A TROPICAL WAVE IS ALSO TRAVERSING THE CARIBBEAN. DRY AIR AND SAHARAN DUST IS E OF THE TROPICAL WAVE SUPPRESSING THUNDERSTORMS AND SHOWERS. SEE ABOVE. NE SURFACE AND UPPER LEVEL WINDS ARE PRODUCING SCATTERED MODERATE CONVECTION OVER W CUBA W OF 80W. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER THE SW CARIBBEAN NEAR 12N80W. THE SOUTHERN EXTENT OF AN UPPER LEVEL TROUGH IS OVER THE LEEWARD ISLANDS. UPPER LEVEL MOISTURE IS OVER CENTRAL AMERICA AND THE W CARIBBEAN W OF 80W. STRONG SUBSIDENCE IS OVER THE REMAINDER OF THE CARIBBEAN. EXPECT...THE DRY AIR BEHIND THE TROPICAL WAVE TO CONTINUE TO SUPPRESS CONVECTION OVER THE NEXT 24 HOURS. THE SW CARIBBEAN MAY HAVE SOME CONVECTION HOWEVER. ATLANTIC OCEAN... SCATTERED MODERATE CONVECTION IS OVER THE THE N BAHAMAS FROM 23N-26N BETWEEN 78W-79W. FURTHER E...A SURFACE TROUGH IS OVER THE W ATLANTIC ALONG 27N67W 24N72W. SCATTERED SHOWERS ARE WITHIN 30 NM OH THE TROUGH. SURFACE RIDGING COVERS THE W ATLANTIC WITH AXIS ALONG 28N W OF 55W. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED NEAR 30N50W PRODUCING SCATTERED MODERATE CONVECTION FROM 28N-31N BETWEEN 60W-62W. AN UPPER LEVEL TROUGH IS OVER THE E ATLANTIC N OF 20N AND E OF 35W. OVER THE TROPICS A RIDGE AN UPPER LEVEL RIDGE EXTENDS FROM W AFRICA TO THE LEEWARD ISLAND ALONG 15N. $$ FORMOSA