000 AXNT20 KNHC 201801 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON JUN 20 2011 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE IN THE ATLC FROM NEAR 12N40W TO 03N42W MOVING W AROUND 20 KT. SCATTERED SHOWERS AND TSTMS ARE OCCURRING WITHIN 120-180 NM OF THE WAVE AXIS. THIS WAVE COINCIDES WITH A MOISTURE MAXIMUM AS INDICATED BY TOTAL PRECIPITABLE WATER SATELLITE IMAGERY. TROPICAL WAVE IN THE E CARIBBEAN SEA FROM NEAR THE EASTERN TIP OF HISPANIOLA S TO THE COAST OF VENEZUELA NEAR 12N69W MOVING W AROUND 15 KT. THE MAJORITY OF THE ASSOCIATED MOISTURE IS LAGGING BEHIND THE WAVE AXIS WITH SCATTERED SHOWERS AND TSTMS OCCURRING WITHIN 180-240 NM E OF THE WAVE. TROPICAL WAVE IN THE SW GULF OF MEXICO EXTENDING FROM NEAR 23N94W S TO THE COAST OF MEXICO NEAR THE NORTHERN END OF THE CHIVELA PASS NEAR 18N95W MOVING W-NW AROUND 15-20 KT. ASSOCIATED MOISTURE IS LIMITED WITH THIS WAVE WITH ISOLATED TO SCATTERED SHOWERS OCCURRING WITHIN 90-120 NM OF THE WAVE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TOP 09N18W TO 07N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N21W TO 06N26W TO 08N39W TO 07N50W TO THE COAST OF SOUTH AMERICA NEAR 07N59W. SCATTERED MODERATE CONVECTION IS WITHIN 60-90 NM OF THE MONSOON TROUGH. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90-120 NM EITHER SIDE OF THE ITCZ BETWEEN 24W AND 30W AND WITHIN 120-180 NM N OF THE ITCZ W OF 43W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER LEVEL RIDGING COVERS THE MAJORITY OF THE GULF REACHING FROM THE FLORIDA BIG BEND SW TO MEXICO NEAR 21N97W. VERY DRY AIR UNDER SUBSIDENCE IS NOTED IN WATER VAPOR SATELLITE IMAGERY. THE EXCEPTION IS IN THE FAR SE GULF WHERE A MID TO UPPER LEVEL TROUGH IS EXITING THE REGION EXTENDING FROM THE STRAITS OF FLORIDA TO THE YUCATAN CHANNEL. THIS FEATURE IS SUPPORTING SCATTERED SHOWERS AND TSTMS OVER THE SE AND S CENTRAL GULF. A SURGE OF 20 KT SE-S WINDS ARE OCCURRING E OF THE TROPICAL WAVE...AS DESCRIBED ABOVE...AND W OF 90W. THE WAVE WILL MOVE INLAND INTO MEXICO LATER TODAY AND TONIGHT SPREADING THE STRONGER WINDS AND SEAS ACROSS THE W GULF WHILE 10-15 KT WINDS WILL PERSIST IN THE E GULF. CARIBBEAN SEA... UPPER LEVEL RIDGING REACHES FROM BELIZE E-SE TO THE CENTRAL CARIBBEAN NEAR 14N70W. A MID TO UPPER LEVEL TROUGH IS JUST N OF THIS RIDGING EXTENDING FROM THE STRAITS OF FLORIDA AND W CUBA TO THE YUCATAN PENINSULA NEAR CANCUN. SCATTERED SHOWERS AND TSTMS ARE OCCURRING AHEAD OF THE TROUGH AND N OF THE RIDGING. ADDITIONAL CONVECTION IS OCCURRING IN THE FAR SW CARIBBEAN WHERE A WEAK MID LEVEL TROUGH IS MOVING W FROM COLOMBIA. ANOTHER MID TO UPPER LEVEL TROUGH IS IN THE E CARIBBEAN REACHING FROM THE VIRGIN ISLANDS SW TO NEAR ARUBA. A TROPICAL WAVE IS AT THE SURFACE AS DESCRIBED IN THE SECTION ABOVE. THE MID TO UPPER LEVEL TROUGH IS ENHANCING ASSOCIATED WAVE CONVECTION WHILE CONTAINING THAT CONVECTION E OF THE WAVE AXIS WITH STRONG UPPER LEVEL SOUTHWESTERLY FLOW. THE WAVE WILL MOVE THROUGH THE CENTRAL CARIBBEAN TONIGHT AND TUE THEN THE W CARIBBEAN WED THROUGH FRI. THIS WAVE WILL SPREAD INCREASING WINDS AND SEAS WESTWARD WITH 20-25 KT EASTERLY WINDS ENCOMPASSING THE MAJORITY OF THE BASIN BY THE END OF THE WEEK. ATLANTIC OCEAN... DRIER AIR ALOFT IS MOVING INTO THE FAR NW PORTION OF THE DISCUSSION AREA AS UPPER LEVEL RIDGING BUILDS IN FROM THE NE GULF OF MEXICO. A MID TO UPPER LEVEL TROUGH IS AHEAD OF THIS RIDGING EXTENDING FROM 32N72W TO THE CENTRAL BAHAMAS. THIS TROUGH IS ADVECTING MOISTURE FROM THE TROPICAL E PACIFIC TO THE NE WITHIN 300-390 NM AHEAD OF THE TROUGH...WITH NUMEROUS SHOWERS AND SCATTERED TSTMS DEVELOPING OVER THE GULF STREAM DURING THE PAST SEVERAL HOURS. RIDGING PRECEDES THIS TROUGH FROM 32N63W TO THE N CENTRAL COAST OF HISPANIOLA WITH A THIN 90-120 NM STRIP OF DRY AIR COINCIDING WITH THE UPPER RIDGE AXIS. ANOTHER MID TO UPPER LEVEL TROUGH EXTENDS FROM 32N44W TO THE VIRGIN ISLANDS. THIS TROUGH HAS BEEN SUPPORTING A FRONT AT THE SURFACE WHICH HAS BEEN DISSIPATING DURING THE PAST SEVERAL HOURS. ELSEWHERE AT THE SURFACE...A RIDGE AXIS REACHES FROM 1021 MB HIGH PRES NEAR 28N44W TO 27N55W CONTINUING DUE WESTWARD ALONG 26N/27N TO THE E COAST OF FLORIDA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LEWITSKY