000 AXNT20 KNHC 270623 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED JUN 27 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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... A TROPICAL WAVE IS ALONG 35/36W S OF 17N MOVING W 10-15 KT. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED S OF 10N WITHIN 150 NM W AND WITHIN 180 NM E OF THE WAVE AXIS. A TROPICAL WAVE IS ALONG 71W S OF 24N MOVING W AT 10-15 KT. UPPER DIFFLUENCE BETWEEN AN UPPER TROUGH NEAR THE BAHAMAS AND AN UPPER RIDGE OVER THE NE CARIBBEAN IS ENHANCING CONVECTION OVER EASTERN CUBA AND HISPANIOLA. SUBSIDENCE OVER THE CENTRAL CARIBBEAN IS SUPPRESSING CONCENTRATED CONVECTION AND ONLY TRADE WIND CUMULUS IS NOTED. AN ELY SURGE IN THE LOW LEVEL FLOW ACCOMPANIES THIS WAVE AS WELL AS A LARGE AREA OF SAHARAN DUST...WHICH HAS ITS WESTERN EDGE ALONG 73W AND EXTENDS E ACROSS THE WINDWARDS. MANY ISLANDS ARE REPORTING REDUCED VISIBILITY FROM DUST OR HAZE. A TROPICAL WAVE EXTENDS FROM COSTA RICA TO WESTERN CUBA ALONG 84W MOVING W AT 10-15 KT. A CLUSTER OF STRONG CONVECTION IS NOTED JUST EAST OF COSTA RICA NEAR 11N82W. SCATTERED CONVECTION IS OVER THE CARIBBEAN NEAR THE WESTERN TIP OF CUBA. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N15W 5N27W 8N37W 5N52W AND MAINLY LOCATED SLIGHTLY N OF ASSOCIATED CLOUDS AND SHOWERS. OTHER THAN CONVECTION ASSOCIATED WITH THE WAVE NEAR 36W...ONLY ISOLATED CONVECTION IS NOTED WITHIN 180 NM OF THE ITCZ AXIS. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER ANTICYCLONE IS CENTERED NEAR 19N105W. NORTHERLY ANTICYCLONIC FLOW EXTENDS ACROSS CENTRAL MEXICO AND THE WESTERN GULF OF MEXICO. AN UPPER TROUGH EXTENDS S ACROSS THE CENTRAL GULF FROM 30N85W THROUGH A WEAK UPPER CYCLONE NEAR 22N88W TO 17N89W. THE UPPER TROUGH HAS INDUCED A LOW LEVEL TROUGH FROM 27N86W TO 21N87W WHICH IS MOVING SLOWLY W. SCATTERED MODERATE CONVECTION ACCOMPANIES THE TROUGH. THE NORTHERN EXTENSION OF A TROPICAL WAVE MOVING THROUGH W CUBA MAY TRIGGER ADDITIONAL CONVECTION NEAR THE YUCATAN PENINSULA. THE CARIBBEAN SEA... AN UPPER TROUGH EXTENDS S FROM THE NW BAHAMAS TO AN UPPER CYCLONE NEAR THE YUCATAN PENINSULA AND S TO BELIZE. AN UPPER ANTICYCLONE OVER NW VENEZUELA IS PRODUCING SOUTHWESTERLY UPPER LEVEL FLOW OVER MOST OF THE CARIBBEAN. DEBRIS MOISTURE IS ADVECTED ENE INTO THE SUBTROPICAL SW ATLC. A BAND OF DRY UPPER AIR IS INDICATED ACROSS THE CENTRAL CARIBBEAN AND IS SUPPRESSING CONVECTION. THE LOW LEVEL FLOW IS ELY AND QUITE BRISK...WITH STREAMING BANDS OF TRADE WIND CUMULUS AND BRIEF LIGHT SHOWERS ACROSS THE AREA S AND E OF JAMAICA. SAHARAN DUST IS ALSO SPREADING W ACROSS THE AREA. VISIBILITY CONDITIONS SHOULD IMPROVE IN THE WINDWARDS TODAY. THE ATLANTIC OCEAN... AN UPPER CYCLONE HAS NEARLY CUT OFF FROM ITS PARENT MID ATLC UPPER TROUGH NEAR 26N78W. AN ASSOCIATED SURFACE TROUGH IS STILL EVIDENT OVER THE NW BAHAMAS. BOTH SYSTEMS ARE SLOWLY SHIFTING WESTWARD. INITIALLY...DRY UPPER AIR SUBSIDENCE WILL SUPPRESS CONVECTION OVER FLORIDA...BUT AS THE UPPER DIFFLUENCE LOCATED E OF THE UPPER LOW MOVES OVER THE NW BAHAMAS AND FLORIDA CONDITIONS WILL BECOME FAVORABLE FOR AN INCREASE IN AFTERNOON CONVECTION. A THE NORTHERN EXTENSION OF THE TROPICAL WAVE ALONG 71W WILL MOVE THROUGH THE BAHAMAS AND THE STRAITS OF FLORIDA THROUGH THE REST OF THE WEEK...AND INCREASE THE CHANCE FOR RAIN E OF ITS AXIS. AN UPPER RIDGE EXTENDING N FROM THE E CARIBBEAN INTO THE SW ATLC BETWEEN 73W AND 58W IS ADVECTING UPPER DEBRIS CIRRIFORM CLOUDS NE OVER THE SUBTROPICAL ATLC UNDER THE RIDGE. ANOTHER UPPER TROUGH EXTENDS ACROSS THE CENTRAL ATLC INTO THE AREA FROM 31N47W TO AN UPPER CYCLONE NEAR 19N51W WITH THE TROUGH CONTINUING TO 10N57W. DRY UPPER AIR ACCOMPANIES THIS TROUGH WITHIN 150 NM EITHER SIDE OF LINE 31N47W 23N51W AND ELSEWHERE FROM 23N TO 7N BETWEEN 54W AND 63W. ANOTHER UPPER TROUGH IS NOTED OVER THE FAR E ATLC ALONG 31N14W TO 23N30W. AN UPPER RIDGE EXTENDS W OFF THE AFRICAN COAST ALONG 17N10W TO 17N20W. SCATTERED TO LOCALLY BROKEN LOW CLOUDS ARE NOTED N OF THE ITCZ E OF 50W. $$ MUNDELL