000 AXNT20 KNHC 182352 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUN 18 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 42W S OF 8N MOVING W NEAR 10 KT. THIS WAVE REMAINS RELATIVELY LOW AMPLITUDE AND EMBEDDED WITHIN THE ITCZ. A MAXIMUM IN DEEP LAYER MOISTURE IS EVIDENT ON TOTAL PRECIPITABLE WATER IMAGERY FROM CIMSS AS WELL. SCATTERED MODERATE CONVECTION IS FROM 4N-8N BETWEEN 37W-42W. A TROPICAL WAVE IS IN THE BAY OF CAMPECHE ALONG 95W S OF 20N INTO THE E PACIFIC MOVING W NEAR 10-15 KT. COINCIDING WITH A MAXIMUM IN DEEP LAYER MOISTURE THIS WAVE EXHIBITS SLIGHT LOW-LEVEL CYCLONIC CURVATURE ACROSS THE WRN BAY OF CAMPECHE AND SRN MEXICO. THIS LOW-LEVEL LIFT ALONG WITH AN UPPER DIFFLUENT PATTERN OVER THE REGION IS SUPPORTING SCATTERED MODERATE/ISOLATED STRONG CONVECTION S OF 22N W OF 95W OVER THE BAY OF CAMPECHE AND SIMILAR CONVECTION OVER PORTIONS OF SRN MEXICO BETWEEN 92W-100W. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N13W 6N24W 4N40W 2N44W AND INTO NE BRAZIL NEAR 1N50W. SCATTERED MODERATE CONVECTION/ISOLATED STRONG CONVECTION IS FROM 8N-14N BETWEEN 12W-20W. SCATTERED MODERATE CONVECTION IS FROM 6N-9N BETWEEN 20W-29W. SIMILAR CONVECTION IS ASSOCIATED WITH THE TROPICAL WAVE ALONG 42W FROM 4N-8N BETWEEN 37W-42W. ...DISCUSSION... GULF OF MEXICO... AN AMPLIFIED UPPER RIDGE EXTENDS ACROSS THE WRN GULF WITH AXIS ALONG 95W. ANTICYCLONIC FLOW DOMINATES THE REGION WITH THE ONLY EXCEPTION BEING THE FAR PORTIONS OF THE SE GULF...THE EXTREME SRN FLORIDA PENINSULA AND STRAITS OF FLORIDA...WHERE UPPER LEVEL TROUGHING EXTENDS FROM THE W ATLC TO ACROSS CUBA. THE UPPER LEVEL TROUGHING SUPPORTS A WEAK SURFACE TROUGH ACROSS SRN FLORIDA AND THE FLORIDA KEYS WITH SCATTERED SHOWERS AND TSTMS OVER THE FLORIDA PENINSULA AND NEARBY COASTAL WATERS N OF 26N E OF 84W. THE REMAINDER OF THE GULF REMAINS RATHER TRANQUIL UNDER THE UPPER LEVEL RIDGE WITH A 1017 MB SURFACE HIGH CENTERED NEAR 28N88W. ALSO OF NOTE...THE TROPICAL WAVE ALONG 95W S OF 20N IN THE BAY OF CAMPECHE ALONG WITH THE UPPER LEVEL RIDGE ACROSS THE WRN GULF IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS SW OF A LINE FROM 18N93W TO 24N98W. CARIBBEAN SEA... AN UPPER LEVEL DIFFLUENT ATMOSPHERE IS EVIDENT ON WATER VAPOR IMAGERY ACROSS CENTRAL AMERICA AND THE SW CARIBBEAN AS SCATTERED SHOWERS AND TSTMS ARE OCCURRING MAINLY W OF A LINE FROM NRN COLOMBIA NEAR 11N73W TO FAR ERN HONDURAS NEAR 15N83W CONTINUING TO THE NE TIP OF THE YUCATAN PENINSULA. UPPER LEVEL TROUGHING DOMINATES THE REMAINDER OF THE NW AND CENTRAL CARIBBEAN W OF 70W AS MODERATELY DRY AIR ON NWLY FLOW ALOFT IS IN PLACE. HOWEVER...LOW-LEVEL INSTABILITY AND MIDDLE TO UPPER LEVEL LIFT DUE TO THE UPPER TROUGH IS GENERATING SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF CUBA...JAMAICA...AND HISPANIOLA. E OF 70W...MOIST SWLY UPPER LEVEL FLOW IS GENERATING SCATTERED HIGH CLOUDS AND ISOLATED SHOWERS ACROSS THE ERN CARIBBEAN. ELY TRADE WINDS UP TO 25 KT ARE OBSERVED ACROSS THE BASIN AND ARE FORECAST TO PERSIST THROUGH THE WEEKEND. ATLANTIC OCEAN... A DEEP LAYER CENTRAL ATLC TROUGH IS SUPPORTING A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N52W AND EXTENDS W-SW TO 29N61W CONTINUING AS A STATIONARY FRONT TO 31N70W AND AS A WARM FRONT FROM THAT POINT INTO A 1013 MB LOW CENTERED NEAR 32N74W. A SURFACE TROUGH EXTENDS S-SW FROM THE SURFACE LOW ALONG 30N75W 27N78W 26N80W AND ACROSS EXTREME SRN FLORIDA INTO THE SE GULF OF MEXICO. ISOLATED SHOWERS ACCOMPANY THE SURFACE TROUGH N OF 27N W OF 70W. ELSEWHERE... SCATTERED SHOWERS ARE WITHIN 200 NM N OF THE STATIONARY FRONT BETWEEN 55W-70W AND WITHIN 150 NM EITHER SIDE OF THE COLD FRONT BETWEEN 45W-55W. ACROSS THE MAJORITY OF THE CENTRAL AND E ATLC A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1028 MB SURFACE HIGH N OF THE DISCUSSION AREA NEAR 41N26W. HOWEVER...A DEEP LAYER LOW OVER THE NE ATLC IS ASSOCIATED WITH A 1015 MB SURFACE LOW NW OF THE CANARY ISLANDS NEAR 30N19W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE LOW IS SUPPORTING ISOLATED SHOWERS N OF 30N BETWEEN 17W-24W. $$ HUFFMAN