000 AXNT20 KNHC 101729 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT MAY 10 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 42W/43W S OF 10N MOVING W 15 KT. VISIBLE IMAGERY REVEALS A FAIR AMOUNT OF LOW-LEVEL CYCLONIC TURNING ...HOWEVER BASED ON A RECENT QSCAT PASS IT IS ABOVE THE SFC. THE MIMIC TPW ANIMATION SHOWS GOOD CONTINUITY OF THIS WAVE WITH ITS OVERALL MOISTURE FIELD THINNING SLIGHTLY AND BECOMING MORE ABSORBED IN THE ITCZ. SCATTERED SHOWERS AND TSTMS ARE WITHIN 180 NM E OF THE AXIS FROM 3N-6N. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N12W 5N23W 2N34W 3N41W 0N50W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 150 NM N AND 180 NM S OF THE AXIS BETWEEN 22W-33W...WITHIN 120 NM N OF THE AXIS BETWEEN 32W-40W...AND WITHIN 120 NM N OF THE AXIS W OF 45W. ...DISCUSSION... THE GULF OF MEXICO... A SPRAWLING MID TO UPPER HIGH IS SITUATED OVER THE BAY OF CAMPECHE PROVIDING ANTICYCLONIC FLOW ALOFT GULF-WIDE. A SUBTROPICAL JET OVER THE EPAC IS ADVECTING HIGH LEVEL CLOUDS ACROSS THE N HALF OF THE GULF...BUT THIS FAINT MOISTURE PLUME DRIES OUT QUICKLY ON THE DOWNWARD BRANCH OF THE RIDGE. AT THE SFC...LIGHT TO MODERATE S TO SW FLOW DOMINATES MUCH OF THE AREA ON THE WRN PERIPHERY OF CENTRAL ATLC SFC HIGH PRES. DESPITE THE MOIST LOW-LEVEL FLOW...SIGNIFICANT CLOUD COVER IS VERY LIMITED AND MAINLY FAIR...VERY WARM AND HUMID CONDITIONS ARE ON TAP FOR THE REGION TODAY. HOWEVER...A CHANGE IS ON THE WAY AS AN UPPER TROUGH OVER THE ROCKIES SHIFTS E SUPPORTING A COLD FRONT WHICH WILL LIKELY ENTER THE NW WATERS TOMORROW MORNING. THE CARIBBEAN SEA... ELONGATED MID TO UPPER TROUGHING STRETCHES FROM PUERTO RICO TO S NICARAGUA WITH A RIDGE BUILDING TO ITS W. A 50-70 KT UPPER JET LIES ON THE E SIDE OF THE TROUGH PRODUCING A PLUME OF MAINLY HIGH LEVEL CLOUDS WITHIN 300 NM E OF THE TROUGH AXIS. THE DENSEST CLOUD COVER IS OVER THE NRN LEEWARD ISLANDS CLOSER TO THE JET CORE. MORE SIGNIFICANT DEEP CLOUDINESS AND EMBEDDED SCATTERED TSTMS IS OVER THE EXTREME SW CARIB S OF 11N W OF 79W TRIGGERED BY LOW-LEVEL CONVERGENCE. OTHERWISE...THE TYPICAL SCATTERED STREAMS OF LOW-LEVEL CLOUDS...WHICH LIKELY CONTAIN ISOLATED SHOWERS...ARE BEING STEERED ACROSS THE SEA BY MODERATE TO STRONG TRADES. THE E TRADES ARE QUITE STRONG...25-30 KT...NEAR THE COLOMBIAN COAST TODAY AND THIS IS EXPECTED TO CONTINUE THROUGH TOMORROW. THE ATLANTIC OCEAN... LARGE SCALE UPPER TROUGHING LIES OVER MUCH OF THE W ATLC. THE MAIN TROUGH IS OVER THE NE CONUS EXTENDING SW TO NEAR 28N65W. ANOTHER AXIS EXTENDS FROM 23N60W THRU PUERTO RICO AND A COUPLE OF OTHER SHORTWAVES ARE MAINTAINING THIS OVERALL BROAD TROUGHING PATTERN. DIFFLUENCE ALOFT AND INSTABILITY NEAR THE SHORTWAVES IS PRODUCING A FEW AREAS OF SIGNIFICANT SHOWER/TSTM ACTIVITY. THE MAIN TWO AREAS...BASED ON IR IMAGERY AND LIGHTNING DATA...IS N OF 31N BETWEEN 65W-69W AND FROM 26N-31N BETWEEN 59W-66W. LIGHTNING ACTIVITY HAS BEEN INCREASING IN BOTH OF THESE CLUSTERS OVER THE PAST COUPLE OF HOURS. A SMALLER WEAKENING PATCH IS FROM 23N-26N BETWEEN 52W-54W. AT THE SFC...A 1021 MB HIGH PRES NEAR 28N51W IS PROVIDING RIDGING ACROSS THE ENTIRE SUBTROPICAL W ATLC. IN THE E ATLC...AN UPPER TROUGH IS SWEEPING E ACROSS THE N WATERS ALONG 22W PROVIDING SOME SUPPORT FOR A FRONTAL BOUNDARY ALONG 32N32W TO A WEAK 1018 MB LOW NEAR 27N37W THEN DISSIPATING TO 23N51W. ONLY A NARROW BAND OF LOW CLOUDS AND ISOLATED SHOWERS ARE EVIDENT WITHIN 90 NM E OF THE LOW/FRONT N OF 26N. MID TO UPPER RIDGING LIES ABOVE THE TROPICS WITH A MEAN AXIS ALONG 8N. UPPER DIFFLUENCE ON THE S SIDE OF THE RIDGE IS ENHANCING CONVECTION IN THE ITCZ W OF 25W. ELSEWHERE...ZONAL FLOW ALOFT IS KEEPING CONDITIONS RATHER TRANQUIL. AT THE SFC...A 1024 MB HIGH SE OF THE AZORES NEAR 35N20W IS PROVIDING LIGHT WINDS IN THE SUBTROPICS AND MAINLY 15-20 KT NE/E WINDS ACROSS THE TROPICS. $$ CANGIALOSI