000 AXPZ20 KNHC 172205 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...SPECIAL FEATURES... HURRICANE LANE WAS CENTERED AT 17.6N 127.1W AT 2100 UTC MOVING NNW OR 330 DEG AT 8 KT. MAXIMUM SUSTAINED WINDS ARE 70 KT WITH GUSTS TO 85 KT AND A MINIMUM PRESSURE OF 989 MB. LANE HAS ACQUIRED VERY PRONOUNCED BANDING FEATURES SINCE YESTERDAY AS SEEN ON VISIBLE SATELLITE IMAGERY. A EYE FEATURE WAS BRIEFLY APPARENT DURING THE DAY...BUT HAS RECENTLY BECOME CLOUDED OVER. IT SATELLITE IMAGERY REVEALS SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 90 NM E AND 60 NM W SEMICIRCLES OF THE CENTER. LANE IS FORECAST TO MOVE N NW AROUND THE WESTERN PERIPHERY OF A DEEP LAYER RIDGE DURING THE NEXT 72 HRS...BUT BE OVER COOLER SEA SURFACE TEMPERATURES CAUSING IT TO WEAKEN TO A TROPICAL STORM NEAR 20.2N 128.9W IN 24 HRS...AND TO A TROPICAL DEPRESSION NEAR 21.6N 131.2W BY 48 HRS. SEE THE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR ADDITIONAL DETAILS. POST-TROPICAL CYCLONE KRISTY IS CENTERED AT 26.2N 119.5W AT 1500 UTC MOVING N-NW OR 340 DEG AT 5 KT. MAXIMUM SUSTAINED WINDS ARE 30 KT WITH GUSTS TO 40 KT AND MINIMUM PRESSURE OF 1009 MB. KRISTY HAS WEAKENED TO A REMNANT LOW AND THERE IS NO SIGNIFICANT DEEP CONVECTION NEAR ITS CENTER. THE REMNANTS OF KRISTY ARE FORECAST TO TURN NORTHEASTWARD AND DISSIPATE OVER THE NEXT 36 HOURS. SEE THE LAST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM NORTHERN COSTA RICA NW TO 14N92W TO 10N103W TO 10N115W WHERE IT ENDS. IT RESUMES AT 15N130W TO 11N138W WHERE IT TRANSITIONS TO THE ITCZ TO 10N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 240 NM S OF THE TROUGH BETWEEN 91W-95W. ...DISCUSSION... ALOFT...BROAD SCALE MID/UPPER RIDGING COVERS THE MAJORITY OF THE AREA EXCEPT THE FAR WESTERN PORTION WHERE BROAD TROUGHING IS PRESENT. AN ANTICYCLONE MOVING E IS ASSOCIATED WITH THE RIDGING...AND IS CENTERED NEAR 28N114W. CONVERGENCE BETWEEN THE TROUGH AND RIDGE AXIS WAS PROVIDING A SOUTHERLY STREAM OF MID TO UPPER LEVEL MOISTURE EVIDENT IN WATER VAPOR IMAGERY. FARTHER E...AN ANTICYCLONE LIES ALONG THE W COAST OF BAJA CALIFORNIA NEAR 29N116W AND EXTENDS A RIDGE AXIS SOUTHWARD THROUGH 20N115W TO JUST S OF HURRICANE LANE NEAR 10N127W. UPPER DIFFLUENCE IS SITUATED TO THE SE OF THE RIDGE. A DEEP LAYER TROUGH AXIS EXTENDS FROM TEXAS ACROSS NORTHERN MEXICO FROM NEAR BROWNSVILLE...TEXAS TO PUERTO VALLARTA...MEXICO. A DRY MID TO UPPER LEVEL AIR MASS AND IMPLIED SUBSIDENCE LIES BEHIND THIS TROUGH. LOW LEVEL MOSITURE IS POOLED AHEAD OF THIS TROUGH ALONG THE W COAST OF MEXICO S OF CABO CORRIENTES...WITH MUCH OF THE CONVECTIVE ACTIVITY FOUND E OF 100W. BROAD UPPER LEVEL DIFFLUENCE CAN BE FOUND OVER MUCH OF THIS AREA BETWEEN AN ANTICYCLONE OVER CENTRAL AMERICA NEAR 15N87W AND A VAST UPPER CYCLONE OFF THE COAST OF PERU NEAR 13S84W. THIS CONVECTION IS DESCRIBED IN THE SECTION ABOVE. A WEAK SURFAC TROUGH IS ALONG 117W FROM 12N T0 16N WITH ISOLATED SHOWERS WITHIN 30 NM ALONG IT. A TIGHT PRES GRADEINT IS FORECAST TO SET UP OVER SRN MEXICO IN ABOUT 48 HRS. THIS SHOULD INDUCE N-NE WINDS OF 20-25 KT THROUGH THE CHIVELA PASS AND THROUGH THE GULF OF TEHUANTEPEC AT THAT TIME WITH SEAS BUILDING TO 8 OR 9 FT. $$ AGUIRRE