000 AXNT20 KNHC 301716 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST MON OCT 30 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1700 UTC. ...TROPICAL WAVES... A LOW AMPLITUDE TROPICAL WAVE IS ALONG 59W S OF 13N MOVING W NEAR 10-15 KT OVER THE PAST 24 HOURS. THIS WAVE IS NOT RECOGNIZABLE IN SATELLITE IMAGES OR IN ANY OF THE AVAILABLE DATA. THE WAVE MAY BE PUSHED FURTHER W IN THE 18Z MAP TO ACCOUNT FOR THE SWIFT STEERING FLOW ON THE S PERIPHERY OF A LOW/MID-LEVEL RIDGE. A TROPICAL WAVE IS ALONG 77W/78W S OF 21N MOVING W NEAR 15 KT. THIS WAVE HAS BECOME MUCH LESS DISTINCT THAN IT WAS YESTERDAY AS IT IS INTERACTING WITH A FRONTAL SYSTEM TO ITS N. THIS TROPICAL WAVE HAS LIKELY SPLIT OR WILL SOON DO SO WITH THE NRN PORTION GETTING PULLED NW WHILE THE SRN PORTION CONTINUES W. A FEW MID LEVEL SWIRLS ARE EVIDENT ABOUT THE WAVE AXIS. THE INTERACTING WITH THE FRONT AND UPPER LEVEL JET IS PRODUCING LOTS OF MOISTURE IN THE CARIBBEAN...BUT SHOWERS AND TSTMS LIKELY CONTRIBUTED MORE DIRECTLY WITH THE WAVE IS WITHIN 180 NM E OF THE AXIS. A TROPICAL WAVE IS IN THE WRN CARIBBEAN ALONG 84W S OF 21N MOVING W 10 TO 15 KT. A BROAD AREA OF MAINLY MID-LEVEL TURNING IS SEEN ON VIS AND IR IMAGERY ABOUT THE WAVE AXIS. SCATTERED SHOWERS AND TSTMS HAVE INCREASED IN INTENSITY OVER THE PAST FEW HOURS BUT REMAIN DISORGANIZED WITHIN 180 NM EITHER SIDE OF THE WAVE AXIS. THIS ACTIVITY IS BEING ENHANCED BY THE UPPER LEVEL JET TO ITS W. FOR MORE INFO ON THE TROPICAL WAVES REFER TO THE CARIBBEAN IN THE DISCUSSION SECTION BELOW. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 8N30W 7N41W 6N58W. SCATTERED MODERATE CONVECTION IS FROM 4N-14N BETWEEN 18W-26W. SCATTERED MODERATE IS ALSO WITHIN 150 NM TO THE N OF THE AXIS BETWEEN 37W-49W. ...DISCUSSION... THE GULF OF MEXICO... A VERY DRY STABLE MID/UPPER LEVEL ENVIRONMENT IS IN PLACE ACROSS THE GULF WITH COOL AIR STRATOCUMULUS CLOUDS STILL VISIBLE. A SHARP MOISTURE GRAD EXISTS JUST SE OF THE AREA WHERE WIDESPREAD MOISTURE LIES IN THE CARIBBEAN. THE DOMINATING SFC HIGH PRES SYSTEM CONTINUES TO SLIDE EASTWARD...NOW CENTERED IN THE SE U.S. THIS HAS ALLOWED LIGHT WINDS TO TURN E AND SELY EXCEPT FOR THE FAR WRN GULF WHERE WINDS ARE A STRONGER 15-20 KT FROM THE S. LOOKING AHEAD OVER THE NEXT FEW DAYS...SOME MOISTURE IN THE CARIBBEAN MAY BACK INTO THE SE GULF PUSHED BY ELY FLOW. A WEAK COLD FRONT MAY MOVE ACROSS THE NRN PORTION OF THE AREA BEFORE BEING REPLACED BY ANOTHER SFC RIDGE WHICH WILL BUILD N OF THE AREA BY MID-LATE WEEK. THE CARIBBEAN SEA... WIDESPREAD MOISTURE EXISTS IN THE CENTRAL AND WRN CARIBBEAN W OF 72W. THERE IS A SHARP MOISTURE GRAD...ASSOCIATED WITH A SWLY UPPER LEVEL JET...BETWEEN THE WRN CARIBBEAN AND THE VERY DRY AIR ALOFT IN THE GULF. DISORGANIZED SCATTERED SHOWERS AND TSTMS ARE EMBEDDED IN THE LARGE MOISTURE PLUME AND ARE BEING ENHANCED BY SEVERAL SFC FEATURES...A TROPICAL WAVE ALONG 77W AND ALONG 84W AS WELL AS THE TAIL END OF A FRONTAL BOUNDARY JUST N OF THE AREA. UPPER DIFFLUENCE AND LOW-LEVEL LIFT IS PRODUCED SCATTERED SHOWERS AND TSTMS ACROSS THE CARIBBEAN W OF 72W. THE STRONGEST ACTIVITY IS NEAR THE TROPICAL WAVES...REFER TO THAT SECTION FOR MORE DETAILS. THE UPPER LEVEL JET...WHICH IS LOCATED BETWEEN A STRONG TROUGH IN THE ERN GULF AND OFF THE U.S. E COAST AND A SPRAWLING UPPER HIGH CENTERED OVER HISPANIOLA...IS DRIVING SOME OF THIS MOISTURE NEWARD INTO THE ATLC. THE ERN AND PART OF THE CENTRAL CARIBBEAN IS QUIET WITH PLENTY OF DRY AIR ALOFT BEING ADVECTED INTO THE AREA. THE ONLY AREA OF ANY SIGNIFICANT SHOWER ACTIVITY IS IN THE EXTREME SE PORTION WHERE SCATTERED SHOWERS AND TSTMS ARE SINKING SWD IN A UPPER DIFFLUENT ZONE ABOVE THE ITCZ S OF 12N E OF 65W. TYPICAL SHALLOW TRADE WINDS SHOWERS ARE STREAMING ACROSS THE ERN CARIB AS WELL AS SEEN ON SAN JUAN 88D. OVER THE NEXT FEW DAYS...MODELS SUGGEST THAT THE LARGE AREA OF MOISTURE WILL GET PUSHED W AND SHRINK IN SIZE AS DRY AIR ALOFT CONTINUES TO BEING ADVECTED INTO THE ERN AND CNTRL CARIB. THE ATLANTIC OCEAN... AN 80-100 KT SWLY JET WHICH LIES BETWEEN A LARGE RIDGE IN THE ATLC AND A STRONG TROUGH OFF THE U.S. E COAST IS ENHANCING AND ADVECTING TROPICAL MOISTURE FROM THE WRN CARIB ACROSS THE BAHAMAS INTO THE WRN ATLC WITHIN 500 NM E OF A LINE FROM THE FLORIDA STRAITS TO 32N69W. AN ASSOCIATED FRONTAL BOUNDARY LIES ALONG 32N56W 26N66W THEN STATIONARY TO THE CENTRAL BAHAMAS. THE MOST ACTIVE WEATHER IS WITHIN 180 NM EITHER SIDE OF THE FRONT FROM 23N-27N WHERE A SFC LOW MAY BE TRYING TO FORM AS IS SUGGESTED BY GFS. A ELONGATED HIGH AMPLITUDE LARGE RIDGE LIES TO THE E OF THE JET COVERING THE AREA W OF 40W N OF 20N. PLENTY OF DRY AIR ALOFT IS ASSOCIATED WITH THIS RIDGE. A LARGE LOW PRES SYSTEM COVERS MUCH OF THE NE PORTION OF THE DISCUSSION AREA...WITH THE SFC LOW ANALYZED AT 1000 MB NEAR 32N28W. THIS LOW IS COLD-CORE AT THE MOMENT WITH A COLD FRONT EXTENDING ALONG 32N25W 23N31W 21N46W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 180 NM E OF THE FRONT N OF 25N AND WITHIN 240 NM OF THE SFC LOW. IN THE DEEP TROPICS...A LARGE ELONGATED UPPER LOW IS CENTERED NEAR 14N44W WITH AN UPPER JET ORIGINATING AT THE BASE OF THE LOW ALONG 10N45W 18N31W 23N16W. THIS STRONG SWLY FLOW IS SHEARING MUCH OF THE CONVECTION IN THE ITCZ TO THE NE. ITCZ CONVECTION IS BEING ENHANCED BY UPPER DIFFLUENT AIR BETWEEN 18W-26W. PLENTY OF DRY AIR ALOFT LIES TO THE W OF THE TROPICAL JET. $$ CANGIALOSI