000 AXNT20 KNHC 161739 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE OCT 16 2007 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 34W/35W S OF 20N MOVING W 10 KT OVER THE PAST 24 HOURS. THIS WAVE HAS BECOME MORE ACTIVE TODAY AS IT NOW LIES IN AN UNSTABLE ENVIRONMENT JUST E OF THE BASE OF A SHARP UPPER TROUGH. DESPITE THE INCREASE IN ACTIVITY...THE OVERALL ORGANIZATION HAS NOT IMPROVED MUCH AS IT REMAINS STRETCHED TO THE NE BY STRONG UPPER SWLY WINDS. SCATTERED SHOWERS AND TSTMS ARE WITHIN 240 NM E OF THE WAVE N OF 10N. A LARGE AREA OF SCATTERED MODERATE CONVECTION EXISTS NEAR THE INTERSECTION OF THE ITCZ FROM 4N-10N BETWEEN 24W-44W. LOW AMPLITUDE TROPICAL WAVE IS ALONG 55W/56W S OF 14N MOVING W 10-15 KT. THIS WEAK WAVE HAS CHANGED LITTLE OVER THE PAST 24 HOURS ONLY CONSISTING OF CYCLONIC TURNING IN THE LOW-LEVEL CLOUD FIELD. TROPICAL WAVE IS OVER PORTIONS OF CENTRAL AMERICA ALONG 87W S OF 20N MOVING W 10-15 KT. THE WEAK LOW THAT HAS BEEN ON THIS WAVE IS NO LONGER EVIDENT. IN FACT...THE WAVE ITSELF IS DIFFICULT TO LOCATE AS THE LOW-LEVEL FLOW IS BEING AFFECTED BY THE WELL-DEFINED TROUGHING IN THE GULF OF MEXICO. SHOWERS AND TSTMS ARE ISOLATED OVER CENTRAL AMERICA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N14W 9N31W 6N48W 6N58W. THERE IS NO SIGNIFICANT CONVECTION OUTSIDE OF THE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE ALONG 34W/35W. DISCUSSION... GULF OF MEXICO... AN AREA OF LOW PRES...ANALYZED 1007 MB...IS CENTERED IN THE SW GULF NEAR 23N94W. THIS LOW LIES AT THE BASE OF A TROUGH WHICH EXTENDS NORTHEASTWARD TO THE FLORIDA PANHANDLE ALONG 26N93W 31N86W. THE LOW ITSELF IS WELL DEFINED ON VISIBLE IMAGES AND IN THE BUOY DATA. HOWEVER...SHOWERS AND TSTMS ARE LIMITED NEAR THE SYSTEM. ACTIVITY IS MORE NUMEROUS TO THE NE OF THE LOW WITHIN 120 NM E OF THE TROUGH AXIS S OF 27N. TSTM ACTIVITY IS STRONGEST N OF 27N WITHIN 180 NM E OF THE TROUGH. DOPPLER RADAR SHOWS THIS MOISTURE MOVING OVER PARTS OF THE FLORIDA PANHANDLE AND EXTREME SE ALABAMA. LOW-LEVEL CONVERGENCE NEAR THE TROUGH COUPLED WITH DIFFLUENCE ALOFT...BETWEEN A SHORTWAVE TROUGH OVER THE NW GULF AND UPPER HIGH NEAR CUBA...ARE THE FORCING ELEMENTS. THERE IS POTENTIAL FOR SOME DEVELOPMENT TODAY OR TOMORROW BEFORE THE UPPER-LEVEL WINDS BECOME UNFAVORABLE IN THE AREA AS THIS SYSTEM MOVES NORTHWESTWARD TO NORTHWARD. THE REMAINDER OF THE GULF IS RELATIVELY QUIET. CARIBBEAN SEA... AN UPPER LOW CONTINUES TRACKING WNW CENTERED TO THE NNW OF COLOMBIA NEAR 15N77W. FAIRLY STRONG S TO SE WINDS ALOFT ON THE E SIDE OF THE LOW IS ADVECTING ABUNDANT TROPICAL MOISTURE INTO THE REGION BETWEEN 65W-72W. MUCH OF THIS MOISTURE IS IN THE FORM OF MID-HIGH LEVEL CLOUDINESS...THOUGH AN AREA OF SCATTERED SHOWERS AND TSTMS EXIST FROM 15N-18N BETWEEN 66W-71W. THE MIMIC TPW ANIMATION SUGGESTS THAT A WEAK TROPICAL WAVE MAY BE IN THIS AREA ENHANCING THIS SHOWER ACTIVITY. MUCH DRIER AIR IS BEING DRAWN IN FROM THE TROPICAL ATLC ACROSS THE LESSER ANTILLES PROVIDING TRANQUIL WEATHER. THE WRN HALF OF THE CARIBBEAN IS EXPERIENCING MAINLY FAIR WEATHER UNDER NELY UPPER FLOW BESIDES FOR THE FEW SHOWERS OVER CENTRAL AMERICA ASSOCIATED WITH THE WEAK TROPICAL WAVE AND ITCZ RELATED ACTIVITY S OF 12N. TRADE WINDS ARE MAINLY MODERATE AND ARE EXPECTED TO REMAIN THAT WAY OVER THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... A SERIES OF FRONTAL BOUNDARIES ARE MOVING ACROSS THE WESTERN ATLANTIC. ONE OF THESE FRONTS CROSSES INTO OUR DISCUSSION AREA ALONG 32N43W AND EXTENDS TO 28N52W. THIS BOUNDARY WAS NEARLY STATIONARY FROM THE BAHAMAS EASTWARD OVER THE PAST FEW DAYS. HOWEVER...BASED ON TODAY'S DATA THE FRONT HAS MOSTLY DISSIPATED IN THE AREA EXCEPT FOR A WEAK LOW-LEVEL TROUGH ALONG 73W WHICH APPEARED TO BREAK OFF FROM THE MAIN BOUNDARY AND IS MOVING W WITH THE LOW-LEVEL FLOW. ISOLATED SHOWERS AND TSTMS ARE LOCATED WITHIN 300 NM E OF THE TROUGH AXIS. HIGH LEVEL CLOUDS ARE SPREAD NE FROM THERE CONTAINED N OF 28N W OF 44W. WIDESPREAD STRONG SUBSIDENCE DOMINATES THE AREA W OF 80W...EXCEPT FOR THE W BAHAMAS WHERE THERE APPEARS TO BE A SMALL SCALE MID-LEVEL TROUGH DEVELOPING. SFC WINDS ARE NOT AS STRONG AS THE PAST COUPLE OF DAYS DUE TO THE WEAKENING PATTERN. CONDITIONS ARE FAIRLY TRANQUIL ACROSS MUCH OF THE REMAINDER OF THE CENTRAL AND E ATLC. THE SFC PATTERN IS MOSTLY CONTROLLED BY RIDGING EXTENDING S/SW FROM A 1019 MB HIGH SITUATED W OF THE CANARY ISLANDS NEAR 29N22W. THIS IS PRODUCING MAINLY LIGHT WINDS OVER THE SUBTROPICAL E AND CENTRAL ATLC...WHILE MODERATE TRADES PERSIST IN THE TROPICS ESPECIALLY NEAR THE LARGE TROPICAL WAVE. THE UPPER PATTERN OVER THE E ATLC CONSISTS OF A LARGE SCALE HIGHLY AMPLIFIED ELONGATED UPPER RIDGE/TROUGH PATTERN. A SWLY JET BRANCH ORIGINATES JUST AHEAD OF THE BASE OF THE TROUGH OVER THE TROPICAL ATLC AND EXTENDS NE TO AFRICA ALONG 12N38W 24N16W. THIS JET IS PROVIDING ENERGY BUT SHEARING THE TROPICAL WAVE ALONG 34W/35W AND SPREADING HIGH LEVEL CLOUDINESS ACROSS THE TROPICAL E ATLC. $$ CANGIALOSI