000 AXNT20 KNHC 240004 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN MAY 23 2010 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 2355 UTC... ...SPECIAL FEATURES... A BROAD DEEP LAYER TROUGH IS OVER THE WESTERN ATLANTIC. AN UPPER LEVEL LOW IS EMBEDDED IN THIS TROUGH...NOTED ON WATER VAPOR IMAGERY...AND SUPPORTS A 1007 MB SURFACE LOW CENTER NEAR 24N70W. A SURFACE TROUGH CROSSES THE LOW CENTER ALONG 29N68W 24N70W 21N70W. MARINE OBSERVATIONS NEAR THE LOW CENTER INDICATE 8 FT TO 12 FT SEAS. GALE FORCE WINDS ARE DEVELOPING NORTHEAST OF THE LOW CENTER FROM 25N TO 32N BETWEEN 65W AND 70W. THIS SYSTEM IS BEEN FURTHER ENHANCED BY THE FORMATION OF A UPPER LEVEL LONGWAVE SOUTHWEST OF THE SYSTEM. WHILE THE CURRENT LOW SHIFTS SOUTHWARD...SATELLITE IMAGERY SUGGESTS THAT A SECOND LOW IS DEVELOPING TO THE NORTH OF THE CURRENT LOW AND IT IS EXPECTED TO BE ADDED TO THE SURFACE UNIFIED MAP BETWEEN 24/0000 UTC AND 24/0600. COMPUTER MODELS SUGGEST THE SECOND LOW WILL STRENGTHEN AND MOVE NORTHWEST TO NEAR 30N71W OVER THE NEXT 24 HOURS. MOST OF THE CONVECTION IS FOUND EAST OF THE SYSTEM FROM 19N TO 32N BETWEEN 55W AND 71W. MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE NORTH EAST OF THE LEEWARD ISLANDS FROM 17N TO 24N BETWEEN 57W AND 62W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 23W FROM 3.5N TO 9N MOVING WEST AT 10 KT. THIS WAVE IS MOVING ALONG WITH THE ITCZ EMBEDDED IN AN AREA OF MAXIMUM DEEP LAYER MOISTURE. SCATTERED MODERATE CONVECTION IS FROM 5N TO 9N BETWEEN 20W AND 25W. TROPICAL WAVE IS ALONG 42W FROM 3N TO 9N MOVING WEST AT 12 KT. THIS WAVE IS EMBEDDED IN AN AREA OF MAXIMUM DEEP LAYER MOISTURE IN TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE TO STRONG CONVECTION IS WEST OF THE WAVE FROM 5N TO 9N BETWEEN 42W AND 47W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 7N20W 5N30W 6N40W 5N50W. ASIDE OF AREAS OF CONVECTION ASSOCIATED WITH TROPICAL WAVES...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 60 NM ON EITHER SIDE OF THE ITCZ. STRONG CONVECTION IS OVER THE WESTERN AFRICA COAST INCLUDING NORTHERN LIBERIA...SIERRA LEONE...AND GUINEA. ...DISCUSSION... GULF OF MEXICO... FAIR WEATHER IS NOTED ACROSS MOST OF THE AREA AS UPPER LEVEL RIDGE OF HIGH PRESSURE COVERS THE GULF OF MEXICO MOVING DRY STABLE AIR ALOFT ACROSS THE BASIN. A SURFACE 1017 MB HIGH PRESSURE SYSTEM IS FOUND OVER THE NORTHERN GULF NEAR 29N88W. ANTI-CYCLONIC FLOW AROUND THIS FEATURE IS MOVING SOME LOW LEVEL MOISTURE FROM THE FAR WESTERN ATLANTIC INTO THE NORTHEAST GULF. THIS AREA OF MOISTURE IS ADVECTING ACROSS THE NORTHERN FLORIDA PENINSULA...INCLUDING THE PANHANDLE. THE COMBINATION OF LOW LEVEL MOISTURE...DIURNAL HEATING...AND INSTABILITY OVER THIS REGION IS PRODUCING A FEW ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS OVER THE NORTHERN FLORIDA PENINSULA AND PANHANDLE NORTH OF 29N. COMPUTER MODELS INDICATE THE CONVECTION IN THIS REGION MAY LINGER OVER THE NEXT 24 HOURS. ELSEWHERE ACROSS THE BASIN...NO SIGNIFICANT CHANGES ARE EXPECTED OVER THE NEXT 24 HRS. CARIBBEAN SEA... WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LONGWAVE ENTERING THE NORTH-NORTHWEST CARIBBEAN PROVIDING STRONG SUBSIDENCE NORTH OF 17N WEST OF 73W. THE EDGE LINE OF THIS UPPER LEVEL LONGWAVE IS FROM 19N69W TO 14N80W GENERATING SCATTERED SHOWERS WITHIN 70 NM ON EITHER SIDE OF THE LINE CROSSING THE NORTH AND CENTRAL CARIBBEAN...ALSO INCLUDING HISPANIOLA...JAMAICA AND PUERTO RICO. AS THE LONGWAVE CONTINUES TO ENTER THE NORTHERN CARIBBEAN...LOOK FOR DRY STABLE AIR TAKING OVER THE REGION NORTH OF 16N WEST OF 71W OVER THE NEXT 24 TO 36 HOURS. A SURFACE TROUGH OS OVER THE FAR SOUTHWEST BASIN WEST OF 78W SOUTH OF 15N GENERATING SCATTERED MODERATE TO HEAVY SHOWERS AND POSSIBLE THUNDERSTORMS IN THIS REGION. THE REMAINDER OF THE BASIN IS EXPERIENCING GENERALLY FAIR WEATHER. ATLANTIC OCEAN... A 1007 MB SURFACE LOW IS OVER THE WESTERN ATLANTIC NEAR 24N70W. A SURFACE TROUGH CROSSES THE LOW CENTER ALONG 29N68W 24N70W 21N70W. THIS SYSTEM COMBINED WITH SIGNIFICANT DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY IS PRODUCING MODERATE TO STRONG CONVECTION FROM 19N TO 32N BETWEEN 55W AND 71W. FOR FURTHER DETAILS REGARDING THE LOW PRESSURE SYSTEM SEE SPECIAL FEATURES DISCUSSION ABOVE. THE FAR WESTERN ATLANTIC WEST OF THE SURFACE LOW/TROUGH IS EXPERIENCING FAIR WEATHER CONDITIONS. THE REMAINDER OF THE CENTRAL AND EASTERN ATLANTIC IS DOMINATED BY AN UPPER LEVEL RIDGE SUPPORTING A SURFACE 1028 MB HIGH NEAR 34N37W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA