000 AXNT20 KNHC 221724 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU MAY 22 2008 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 23W S OF 12N MOVING W 10 KT. THIS WAVE REMAINS FAIRLY WELL DEFINED WITH VISIBLE IMAGES SHOWING LOW-LEVEL CYCLONIC TURNING ALONG THE AXIS AND A CLEAR PERTURBATION IN THE ITCZ. HOWEVER...MUCH OF THIS TURNING IS LOW LATITUDE CENTERED NEAR 6N. SCATTERED SHOWERS AND TSTMS ARE WITHIN 150 NM EITHER SIDE OF THE AXIS S OF 9N. TROPICAL WAVE IS ALONG 56W/57W S OF 11N MOVING W 10-15 KT. THIS WAVE IS EASY TO LOCATE TODAY AS AN INVERTED-V SHAPE IS EVIDENT IN THE LOW-LEVEL CLOUD PATTERN. HOWEVER...CONVECTION IS MINIMAL...LIKELY SUPPRESSED BY DRY MID-UPPER FLOW TO THE W OF A HIGH AMPLITUDE TROUGH. TROPICAL WAVE IS OVER PANAMA ALONG 80W S OF 12N MOVING W 10 KT. THIS WAVE HAS BECOME VERY DIFFICULT TO TRACK AS THE S PORTION IS NOW EMBEDDED IN STRONG SW/W LOW-LEVEL FLOW WHICH IS LEADING TO A LARGE AREA OF CONVECTION OVER THE TROPICAL EPAC S OF PANAMA AND COSTA RICA. SHOWERS AND TSTMS ARE LOCATED OVER THE W CARIB...BUT THIS SEEMS MORE ASSOCIATED WITH THE UPPER PATTERN. SEE CARIBBEAN SECTION BELOW FOR DETAILS. ..THE ITCZ... ITCZ AXIS IS CENTERED ALONG 5N10W 7N21W 2N30W 1N40W 1N50W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS E OF 13W AND WITHIN 150 NM N OF THE AXIS BETWEEN 36W-46W. ...DISCUSSION... GULF OF MEXICO... STRONG SW UPPER FLOW IS STILL SET UP OVER THE REGION BETWEEN A DEEP LAYER COMPLEX LOW OVER THE ROCKIES AND MID TO UPPER RIDGING OVER THE CARIBBEAN. DRY AIR ALOFT IS ESTABLISHED OVER THE SW GULF...WHERE THE FLOW IS CONFLUENT...BUT IT IS STILL FAIRLY MOIST OVER THE E HALF DUE TO A DIFFLUENT UPPER PATTERN. IN FACT...DOPPLER RADAR AND LIGHTNING DATA ARE DEPICTING A FAIRLY ACTIVE AREA OF SCATTERED SHOWERS AND TSTMS OVER THE N CENTRAL AND NE WATERS N OF 27N E OF 89W. ISOLATED ACTIVITY IS OCCURRING FARTHER WEST N OF 28N BETWEEN 89W-95W AND OVER THE SE WATERS NEAR THE COAST OF FLORIDA. AT THE SFC...SLY 15-20 KT WINDS ARE FAIRLY UNIFORM ACROSS THE AREA BUILDING SEAS TO 8 FT OVER THE NW WATERS. THESE OVERALL MOIST CONDITIONS SHOULD CONTINUE TO HOLD UNTIL A BACK DOOR TYPE COLD FRONT DRIES OUT FLORIDA AND THE NE WATERS LATE THIS WEEKEND AND EARLY NEXT WEEK. CARIBBEAN SEA... AN UPPER LOW IS SPINNING OVER THE E CARIB CENTERED NEAR 15N68W. THIS FEATURE IS ENHANCING DRY AIR ON ITS W SIDE AND IS BARELY MOISTENING THE UPPER LEVELS TO ITS E...AS IT IS EMBEDDED IN A SUBSIDENT ENVIRONMENT ASSOCIATED WITH LARGE SCALE RIDGING. SCATTERED SHOWERS AND TSTMS ARE OVER THE SW/W PORTION OF THE BASIN FROM 12N-18N BETWEEN 78W-84W. THIS ACTIVITY IS ASSOCIATED WITH UPPER DIFFLUENCE AND SOME INTERACTION WITH A NEARBY TROPICAL WAVE. MORE NUMEROUS MODERATE CONVECTION LIES S OF THE AREA OVER THE TROPICAL EPAC. QSCAT DATA FROM THIS MORNING REVEALED SE 20 KT WINDS OVER THE NW CARIB...WHICH CONTINUE IN THE GULF OF MEX. FAIRLY RELAXED E/SE TRADES ARE OCCURRING ELSEWHERE. ATLANTIC OCEAN... A BROAD FLAT MID TO UPPER RIDGE LIES OVER THE W ATLC PROVIDING STABLE CONDITIONS S OF 25N. HIGH LEVEL CLOUDS LIE OVER THE REGION N OF 25N W OF 50W ASSOCIATED WITH STRONG ZONAL FLOW ON THE N PERIPHERY OF THE RIDGE. MUCH OF THE DEEPER MOISTURE LIES JUST N OF THE REGION ASSOCIATED WITH A FRONTAL BOUNDARY. FARTHER E...A LARGE SCALE HIGH AMPLITUDE TROUGH HAS MOVED LITTLE OVER THE PAST DAY OR TWO ANCHORED BY AN UPPER LOW NEAR 30N39W AND EXTENDS SSW TO 2N45W. UPPER LEVEL DIFFLUENCE AND STRONG SW FLOW ALOFT...BETWEEN THE UPPER TROUGH AND AN UPPER HIGH OVER W AFRICA...IS SPREADING HIGH LEVEL CLOUDINESS ACROSS THE E ATLC. SCATTERED SHOWERS ARE POSSIBLE ALONG AND JUST W OF THE TROUGH AXIS FROM 16N-22N BETWEEN 40W-46W. AT THE SFC...A QUASI-STATIONARY 1025 MB HIGH CENTERED NEAR 33N39W IS PROVIDING MODERATE NE/E TRADES ACROSS THE TROPICS AND MAINLY LIGHT WINDS ACROSS THE SUBTROPICS. HOWEVER...THE EXCEPTION TO THIS IS ON ITS NW PERIPHERY N OF 28N BETWEEN 55W AND 75W WHERE STRONG SW WINDS EXIST IN RESPONSE TO A LOW PRES SYSTEM OVER THE N ATLC. $$ CANGIALOSI/BELL