000 AXPZ20 KNHC 170951 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC MON SEP 17 2012 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...SPECIAL FEATURES... HURRICANE LANE IS CENTERED AT 15.9N 126.1W AT 0900 UTC MOVING NNW OR 335 DEG AT 8 KT. MAXIMUM SUSTAINED WINDS ARE 65 KT WITH GUSTS TO 80 KT AND A MINIMUM PRESSURE OF 993 MB. CURRENTLY SCATTERED STRONG CONVECTION IS OBSERVED SE AND NW OF THE CENTER WITHIN 30 NM EITHER SIDE OF A LINE FROM 15.5N125W TO 16.5N127W. SCATTERED MODERATE CONVECTION IN OBSERVED IN BANDS ELSEWHERE WITHIN 180 NM OF CENTER. BOTH THE ATMOSPHERIC AND OCEANIC ENVIRONMENTS ARE FAVORABLE FOR ABOUT THE NEXT 24 HOURS BUT THEREAFTER LANE WILL TRACK OVER COOLER OCEAN WATERS AND WILL BEGIN TO EXPERIENCE WIND SHEAR AND THUS IS FORECAST TO WEAKEN TO A TROPICAL STORM AGAIN ON TUE. SEE THE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR ADDITIONAL DETAILS. TROPICAL DEPRESSION KRISTY IS CENTERED AT 25.9N 119.4W AT 0900 UTC MOVING NNW OR 330 DEG AT 6 KT. MAXIMUM SUSTAINED WINDS ARE 30 KT WITH GUSTS TO 40 KT AND MINIMUM PRESSURE OF 1009 MB. ALTHOUGH A SMALL AREA OF CONVECTION HAS BEEN BURSTING INTERMITTENTLY W OF THE EXPOSED CENTER...THERE IS NO SIGNIFICANT CONVECTION NOTED AT THE MOMENT. KRISTY IS EXPECTED TO FURTHER WEAKEN TO A REMNANT LOW PRES LATER TODAY AS THE CENTER MOVES OVER COLDER SURFACE WATERS. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS WESTWARD ACROSS THE SW CARIBBEAN ALONG 10N FROM THE NW COAST OF COLOMBIA TO ACROSS CENTRAL COSTA RICA THEN TURNING SLIGHTLY NW TO THE E PACIFIC AT 11N92W...THEN TURNS SW TO 08N101W...WIGGLES ALONG 08N TO NEAR 110W WHERE IT TURNS NW AGAIN TO 11N115W WHERE IT LOSES IDENTITY. SURFACE WINDS INDICATE THE MONSOON TROUGH RESUMES TO THE SW OF TROPICAL CYCLONE LANE NEAR 14N120W...AND CONTINUES SW THROUGH A PERSISTENT EMBEDDED LOW PRES AT 12N133W...AND CONTINUES SW TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION ACCOMPANIED BY FREQUENT LIGHTNING IS INDICATED FROM 03N TO 10N BETWEEN 82W AND 92W AND ALSO WITHIN 60 NM OF 08N95W. ISOLATED MODERATE TO STRONG CONVECTION IS OBSERVED WITHIN 120 NM EITHER SIDE OF A LINE FROM 16N114W TO 11N120W AND LINE FROM 11N127W TO 15N130W. CURRENTLY SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 30 NM OF 11N133W ASSOCIATED WITH THE EMBEDDED LOW PRES AT 12N133W. SCATTERED MODERATE ISOLATED STRONG CONVECTION...WITH FREQUENT LIGHTNING DETECTED...IS OBSERVED WITHIN 30 NM OF COLOMBIAN COAST AT 03N78W AND ALSO WITHIN 60 NM OF CENTRAL AMERICAN COAST AT 13N88W AND ALONG THE COAST FROM 93W TO 100W. ...DISCUSSION... A LONGWAVE UPPER RIDGE DOMINATES THE EASTERN N PACIFIC STEMMING FROM AN UPPER ANTICYCLONE CENTERED AT 27N116W...AND RIDGING NE BEYOND 32N118W TO ACROSS THE NORTHERN COAST OF CALIFORNIA. AN UPPER RIDGE ALSO EXTENDS SW FROM THE ANTICYCLONE TO A CREST AT 17N131W. AN EMBEDDED UPPER CYCLONE HAS CUT OFF NEAR 36N135W WITH AN UPPER TROUGH EXTENDING SW FROM 32N135W TO BEYOND 18N140W. A SOUTHERLY 60 KT JET IS INDUCED E OF THE TROUGH ALONG THE W PERIPHERY OF THE UPPER RIDGE WITHIN 120 NM OF LINE FROM 22N133W TO 32N128W. TROPICAL CYCLONE LANE IS MOVING NW INTO AND ERODING THE SOUTHERN RIDGE SEGMENT. THE UPPER ANTICYCLONE IS EXPECTED TO SHIFT SE REACHING OVER THE SOUTHERN TIP OF THE BAJA PENINSULA ON TUE. THE CUTOFF UPPER CYCLONE JUST NW OF THE AREA IS EXPECTED TO CONTINUE LIFTING NE WITH THE UPPER TROUGH EXTENDING S FROM THE CYCLONE SHIFTING SLIGHTLY NW OF THE AREA TONIGHT. THE UPPER JET OVER THE NW PORTION WILL BROADEN TO ABOUT 600 NM WIDE BY EARLY TUE. IMMEDIATELY TO THE E OF THE LARGE UPPER RIDGE IS A DEEP LAYERED CYCLONE OVER S CENTRAL TEXAS...WITH AN UPPER TROUGH EXTENDING SW ACROSS NORTHERN MEXICO TO THE MEXICAN COAST AT 23N106W...THEN THE TROUGH NARROWS INTO A FINE LINE...OR CYCLONIC SHEAR AXIS... AS IT CONTINUES W ALONG 23N TO JUST S OF THE DISSIPATING TROPICAL CYCLONE KRISTY...THEN TURNS SW AROUND THE W PERIPHERY OF THE ANTICYCLONE ASSOCIATED WITH TROPICAL CYCLONE LANE...TO A TROUGH BASE OVER THE EQUATOR AT 127W. THE PORTION OF THIS UPPER TROUGH TO THE N OF 15N DEFINES THE BOUNDARY OF VERY DRY AIR ALOFT FROM A MOIST UPPER ATMOSPHERE OVER THE TROPICS E OF 128W. THERE IS HOWEVER A LITTLE DEBRIS MOISTURE FROM KRISTY EVAPORATING WITHIN 75 NM OF 25.5N122W. SOME OF THE MOISTURE FROM LANE IS ADVECTED SW TO NEAR 05N132W. AN UPPER ANTICYCLONE IS OVER CENTRAL AMERICA NEAR 16N92W WITH ITS ANTICYCLONIC ENVELOPE COVERING THE UPPER LEVELS N OF 05N BETWEEN 82W AND 107W. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING CONVECTION ALONG THE E PACIFIC MONSOON TROUGH...AND ALONG THE COAST OF COLOMBIA AND CENTRAL AMERICA AS PREVIOUSLY DESCRIBED. THE RESULTANT UPPER DEBRIS MOISTURE IS MOVING AROUND THIS UPPER RIDGE...WITH SOME CONCENTRATING INTO A PLUME THAT CONTINUES NE ACROSS THE WESTERN GULF OF MEXICO MERGING WITH ADDITIONAL DEBRIS MOISTURE FROM CONVECTION OVER THE NW GULF OF MEXICO...BEFORE FANNING OUT OVER THE ENTIRE SE CONUS AND CONTINUING E OFF THE CAROLINAS ACROSS THE SUBTROPICAL W ATLANTIC. VERY DRY UPPER AIR INDICATED TO THE S OF 03N BETWEEN 80W AND 105W EXTENDING N FROM A LARGE UPPER ANTICYCLONE OVER THE NE SOUTH PACIFIC. $$ NELSON