000 AXPZ20 KNHC 161002 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN SEP 16 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... TROPICAL STORM LANE CENTERED NEAR 13.3N 124.5W AT 0900 UTC MOVING W OR 280 DEG AT 6 KT. MAXIMUM SUSTAINED WINDS ARE 50 KT WITH GUSTS TO 60 KT AND A MINIMUM PRESSURE OF 1001 MB. LANE CONTINUES TO BECOME BETTER ORGANIZED WITH SCATTERED MODERATE TO STRONG CONVECTION OBSERVED WITHIN 150 NM S AND 60 NM N OF CENTER...WITH SCATTERED MODERATE CONVECTION ALSO NOTED OUT TO 180 NM OVER THE NW QUADRANT IN A FEEDER BAND. BOTH THE ATMOSPHERIC AND OCEANIC ENVIRONMENTS ARE FAVORABLE AND LANE IS FORECAST TO SLOWLY INTENSIFY REACHING MINIMAL HURRICANE STRENGTH AS IT TRACKS NW OVER THE NEXT 48 HRS. AFTER ABOUT 2 DAYS LANE WILL BEGIN TO TRACK OVER COOLER OCEAN WATERS AND IS THEN EXPECTED TO BEGIN TO WEAKEN. SEE THE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR ADDITIONAL DETAILS. TROPICAL STORM KRISTY CENTERED NEAR 24.1N 117.1W AT 0900 UTC MOVING NW OR 315 DEG AT 8 KT. MAXIMUM SUSTAINED WINDS ARE 35 KT WITH GUSTS TO 45 KT AND MINIMUM PRESSURE OF 1004 MB. KRISTY IS WEAKENING WITH SCATTERED MODERATE CONVECTION OBSERVED WITHIN 45 NM OVER THE SE QUADRANT AND ALSO WITHIN A BAND OVER ITS SW SEMICIRCLE...ROUGHLY WITHIN 30 NM EITHER SIDE OF A LINE FROM 23N118W TO 23N119W TO 24N120W TO 25N118W. KRISTY IS FORECAST TO TRACK OVER COOL SEA SURFACE WATERS AND IS EXPECTED TO WEAKEN TO A REMNANT LOW PRESSURE LATER TODAY. SOUTHERLY SWELL FROM KRISTY IS PRODUCING COMBINED SEAS OF 4 TO 7 FT ALONG THE PACIFIC COAST THE BAJA CALIFORNIA PENINSULA TO THE S OF 28N...WITH THESE CONDITIONS EXPECTED TO SUBSIDE TO 3 TO 5 FT EARLY TONIGHT. 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 FROM THE NW COAST OF COLOMBIA AT 08N77W DISSECTING PANAMA AND COSTA RICA TO THE E PACIFIC AT 11N88W...THEN TURNS SW TO 08N97W...THEN TURNS NW AGAIN TO 11N107W WHERE IT LOSES IDENTITY. SURFACE WINDS INDICATE THE MONSOON TROUGH RESUMES TO THE SW OF TROPICAL CYCLONE LANE NEAR 12N127W...AND CONTINUES SW THROUGH A PERSISTENT EMBEDDED LOW PRES AT 12N133W...AND CONTINUES SW TO BEYOND 10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION...WITH FREQUENT LIGHTNING...IS OBSERVED WITHIN 75 NM OF COLOMBIAN COAST FROM 03N TO 08N. SIMILAR CONVECTION IS NOTED WITHIN 240 NM EITHER SIDE OF A LINE FROM 08N91W TO 08N98W TO 12N100W...CURRENTLY DISSIPATING WITHIN 150 NM OF 09.5N113W...WITHIN 60 NM EITHER SIDE A LINE FROM 10N131W TO 13N134W IN ASSOCIATION WITH THE EMBEDDED LOW AT 12N133W...AND PERSISTING ALONG THE WESTERN SEGMENT OF THE MONSOON TROUGH WITHIN 30 NM EITHER SIDE OF A LINE FROM 10N133W TO 09N137W TO 09N140W. ...DISCUSSION... A LONGWAVE UPPER RIDGE DOMINATES THE EASTERN N PACIFIC STEMMING FROM AN UPPER ANTICYCLONE CENTERED AT 29N123W AND RIDGING NE TO WELL BEYOND 35N120W. AN UPPER RIDGE ALSO EXTENDS SW TO A SHARP CREST OVER THE DEEP TROPICS AT 12N140W. AN EMBEDDED UPPER SHORTWAVE TROUGH IS NOTED WITHIN THE LARGER RIDGE FROM THE NW CORNER OF THE CONUS TO 40N140W AND INTO AN UPPER CYCLONE AT 33N138W...WITH THE UPPER TROUGH CONTINUING S ALONG 140W TO BEYOND 20N141W. A SOUTHERLY JET CONTINUES...BUT HAS WEAKENED TO ABOUT 60 KT...OVER THE NW PORTION OF THE DISCUSSION AREA WITHIN 180 NM OF LINE FROM 20N140W TO 30N133W. BOTH OF THE TROPICAL CYCLONES ARE MOVING W INTO AND ERODING THE EASTERN PORTION OF THE UPPER ANTICYCLONIC FLOW. WEAK UPPER DIFFLUENCE IS NOTICED S OF THE TROPICAL UPPER RIDGE OVER THE DEEP TROPICS...AND IS ENHANCING CONVECTION ALONG THE WESTERN SEGMENT OF THE MONSOON TROUGH AND ITS EMBEDDED SURFACE LOW AT 12N133W. SOME OF THE DEBRIS MOISTURE IS ADVECTED N ACROSS THE UPPER RIDGE AXIS BETWEEN 132W AND 144W...BUT IT EVAPORATES IN THE SOUTHERN PORTION OF THE UPPER JET PREVIOUSLY DESCRIBED. VERY DRY AIR ALOFT IS INDICATED OVER THE DISCUSSION AREA N OF 17N BETWEEN 119W AND 142W. THE UPPER ANTICYCLONE IS EXPECTED TO SHIFT A LITTLE FURTHER N TODAY...THEN TURN SE REACHING OVER THE CENTRAL BAJA PENINSULA ON MON. THE 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 ON MON...AS THE UPPER JET OVER THE NW PORTION BROADENS TO ABOUT 660 NM WIDE. IMMEDIATELY TO THE E OF THE LARGE UPPER RIDGE IS A DEEP LAYERED CYCLONE OVER NEW MEXICO/TEXAS BORDER...WITH AN UPPER TROUGH EXTENDING SW ACROSS THE CENTRAL BAJA PENINSULA...INTO AN UPPER CYCLONE NEAR TROPICAL CYCLONE KRISTY...WITH THE UPPER TROUGH STILL CONTINUING SW THROUGH 18N125W...AND THEN WRAPPING AROUND THE WESTERN PERIPHERY OF TROPICAL CYCLONE LANE. AN UPPER ANTICYCLONE IS AT 21N107W AND RIDGING SW TO A CREST OVER TROPICAL CYCLONE LANE. A BROAD INVERTED UPPER TROUGH IS NOTED OVER THE DEEP TROPICAL PACIFIC TO THE S OF 17N BETWEEN 95W AND 110W. AN UPPER ANTICYCLONE IS QUASI STATIONARY OVER THE NW CARIBBEAN AT 16N85W...WITH ITS ENVELOPE OF UPPER ANTICYCLONIC FLOW COVERING THE DISCUSSION AREA N OF 06N BETWEEN 82W AND 95W. THESE FEATURES COMBINE TO SET UP AN AREA OF UPPER DIFFLUENCE OVER CENTRAL AMERICA AND THE TROPICAL PACIFIC BETWEEN 100W AND 120W ENHANCING THE TROPICAL PACIFIC CONVECTION PREVIOUSLY MENTIONED. UPPER DEBRIS MOISTURE IS NOTED TO THE N OF 07N BETWEEN 82W AND 100W...AND S OF 15N BETWEEN 100W AND 130W...WITH VERY DRY UPPER AIR INDICATED TO THE S OF 07N BETWEEN 78W AND 100W EXTENDING N FROM A LARGE UPPER ANTICYCLONE OVER THE NE SOUTH PACIFIC. SOME OF THE DEBRIS MOISTURE FROM TROPICAL CYCLONE KRISTY CONCENTRATES IN A PLUME THAT TURNS NE ACROSS NORTHEASTERN OLD MEXICO...THEN FANS OUT AS IT MERGES WITH ADDITIONAL MOISTURE OVER W TEXAS...ALL SPREADING E ACROSS EASTERN TEXAS AND ACROSS THE SE CONUS AND NOW MOVING OVER THE ATLANTIC OFFSHORE THE CAROLINAS. ELSEWHERE AT THE SURFACE...A BROAD RIDGE COVERS THE AREA N OF 20N W OF 122W. A SURFACE RIDGE ORIENTATED FROM NNW TO SSE OVER THE EASTERN PORTION OF OLD MEXICO CONTINUES TO PRODUCE THE NORTHERLY SURGES AT 20 TO 25 KT INTO...AND JUST DOWNSTREAM...OF THE GULF OF TEHUANTEPEC. THESE DRAINAGE WINDS WILL QUICKLY DIMINISH AFTER SUNRISE TODAY. $$ NELSON