000 AXNT20 KNHC 121756 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON JUL 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC... ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 10N25W TO 19N24W MOVING W AT 15-20 KT. THE WAVE AXIS IS POSITIONED BETWEEN A WEAKENING NORTHERN VORTEX NW OF THE CAPE VERDE ISLANDS NEAR 18N27W AND A MAXIMUM IN DEEP LAYER MOISTURE TO THE EAST BETWEEN 18W-24W. BROAD CYCLONIC TURNING OF THE LOW-LEVEL CLOUD FIELD IS ALSO NOTED ON SATELLITE BETWEEN 21W-30W IN THE VICINITY OF THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS FROM 06N-15N BETWEEN 17W-26W. TROPICAL WAVE EXTENDS FROM 07N-18N ALONG 45W MOVING W AT 20 KT. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY BETWEEN 40W-50W. HOWEVER...DUE TO A DRY SAHARAN AIR LAYER AND ASSOCIATED DUST IN PLACE N OF 11N ACROSS MUCH OF THE ATLC...CONVECTION IS LIMITED NEAR THE WAVE AND MOSTLY CONFINED TO THE ITCZ. SCATTERED MODERATE CONVECTION IS FROM 06N-11N BETWEEN 43W-48W. TROPICAL WAVE EXTENDS FROM 21N81W TO 07N83W MOVING W AT 15-20 KT. THE WAVE REMAINS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE THAT COVERS MUCH OF THE NW CARIBBEAN W OF 80W AS INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE ALSO LIES WEST OF A DRY SAHARAN AIR LAYER LOCATED OVER MUCH OF THE CENTRAL AND EASTERN CARIBBEAN. COMPARING YESTERDAYS KINGSTON JAMAICA SOUNDING FROM TODAY...BELOW 600 MB...KINGSTON IS WITHIN A FAR DRIER AIR LAYER DENOTING THE PASSAGE OF THE WAVE. DUE TO THIS LAYER...SCATTERED MODERATE TO STRONG CONVECTION IS MAINLY CONFINED S OF 15N BETWEEN 76W-85W...OVER THE SW CARIBBEAN AND INLAND PORTIONS OF COSTA RICA AND NICARAGUA. TROPICAL WAVE EXTENDS FROM 18N89W ACROSS GUATEMALA AND INTO THE E PACIFIC NEAR 08N90W MOVING W AT 10-15 KT. MOST CONVECTION IS CONFINED TO THE E PACIFIC REGION...HOWEVER...SCATTERED SHOWERS ARE OVER PORTIONS OF CENTERED AMERICA AND SOUTHERN MEXICO S OF 19N BETWEEN 87W-92W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 15N17W 12N24W 09N43W 09N64W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 03N-07N BETWEEN 28W-40W. SIMILAR CONVECTION IS FROM 03N-07N BETWEEN 48W-53W AND FROM 07N-11N BETWEEN 50W-60W. ...DISCUSSION... GULF OF MEXICO... A DRY AND STABLE AIRMASS LIES ACROSS MUCH OF THE GULF OF MEXICO AROUND AN UPPER LEVEL RIDGE CENTERED OVER SOUTHERN TEXAS NEAR 29N99W MAINTAINING FAIR CONDITIONS ACROSS MUCH OF THE BASIN. HOWEVER...A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING OVER THE NE GULF AND PORTIONS OF FLORIDA NE OF A LINE FROM 30N87W TO 27N83W. AT THE SURFACE...RIDGING DOMINATES ANCHORED BY A 1016 MB HIGH CENTERED WEST OF KEY WEST FLORIDA NEAR 25N84W. LIGHT ANTICYCLONIC FLOW IS AROUND THE SURFACE RIDGE E OF 95W WITH STRONGER SOUTHERLY WINDS REACHING UP TO 20 KT ALONG THE TEXAS GULF COAST. THE SURFACE RIDGE AXIS IS FORECAST TO GRADUALLY SLIDE NORTHWARD BY MID-WEEK WITH CONTINUED FAIR WEATHER. CARIBBEAN SEA... A PAIR OF TROPICAL WAVES ARE LOCATED ACROSS THE WESTERN CARIBBEAN AND CENTRAL AMERICA BRINGING ENHANCED MOISTURE AND PRECIPITATION MAINLY SW OF A LINE FROM THE YUCATAN PENINSULA TO NORTHERN COLOMBIA NEAR 12N72W. THE TROPICAL WAVES AND AN UPPER LEVEL DIFFLUENT ENVIRONMENT ARE SUPPORTING SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF THE SW CARIBBEAN AND CENTRAL AMERICA S OF 18N. THE DIFFLUENCE ALOFT IS LARGELY DRIVEN BETWEEN AN UPPER LEVEL RIDGE COVERING THE NW CARIBBEAN AND YUCATAN PENINSULA AND AN UPPER LEVEL TROUGH COVERING THE EASTERN CARIBBEAN EXTENDING FROM THE LESSER ANTILLES TO NEAR 12N72W. THIS UPPER LEVEL TROUGH IS ACCOMPANIED BY DRY AIR EXTENDING FROM THE TROPICAL ATLC. SEVERAL STATIONS ARE ALSO INDICATING THE PRESENCE OF DUST AND/OR HAZE...AND WITH THE SAHARAN AIR LAYER IN PLACE...MUCH OF THE CARIBBEAN E OF 80W IS EXPERIENCING GENERALLY FAIR WEATHER. ATLANTIC OCEAN... AN UPPER LEVEL SHORTWAVE TROUGH IS LOCATED OFF THE EASTERN U.S. SEABOARD AND EXTENDS AN UPPER LEVEL TROUGH AXIS TO NEAR 30N74W. THIS UPPER LEVEL TROUGHING ALONG WITH A WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE W ATLC AND GULF OF MEXICO IS PROVIDING FOR AN AREA OF INCREASED MOISTURE AND INSTABILITY GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 20N BETWEEN 65W-80W. THE MOST INTENSE AREA OF ACTIVITY CURRENTLY IS LOCATED OVER THE SE BAHAMAS AND TURKS AND CAICOS ISLANDS FROM 21N-24N BETWEEN 68W-74W. ELSEWHERE AT THE SURFACE...RIDGING DOMINATES THE REMAINDER OF THE BASIN E OF 65W ANCHORED BY A 1031 MB HIGH CENTERED NEAR 40N46W. A DRY SAHARAN AIR LAYER ACCOMPANIED BY DUST COVERS MUCH OF THE EASTERN AND CENTRAL ATLC PROVIDING FOR GENERALLY FAIR CONDITIONS. ALOFT...MOSTLY MODERATE TO STRONG DRY AIR IS NOTED ON WATER VAPOR IMAGERY BETWEEN 25W-60W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN