000 AXPZ20 KNHC 170327 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...SPECIAL FEATURES... TROPICAL STORM LANE CENTERED NEAR 15.0N 125.8W AT 0300 UTC MOVING NW OR 320 DEG AT 8 KT. MAXIMUM SUSTAINED WINDS ARE 60 KT WITH GUSTS TO 75 KT AND A MINIMUM PRESSURE OF 957 MB. LITTLE OVERALL CHANGE WAS NOTED IN THE CLOUD PATTERN OF LANE SO FAR DURING THE DAY. A SMALL CENTRAL DENSE OVERCAST WITH AN OVERSHOOTING TOP IS SEEN ON THE LAST VISIBLE SATELLITE IMAGES. SCATTERED STRONG CONVECTION IS WITHIN 30 NM OF THE CENTER. SCATTERED MODERATE CONVECTION IS ELSEWHERE WITHIN 120 NM N SEMICIRCLE OF THE CENTER. ATMOSPHERIC CONDITIONS AND WARM SEA SURFACE TEMPERATURES WILL ALLOW FOR LANE TO STRENGTHEN INTO A HURRICANE IN 12 HRS NEAR 16.0N 126.6W AS IT TRACKS NW AND INTO MON NIGHT BEFORE IT WEAKENS BACK TO A TROPICAL STORM AS MOVES OVER COOLER SEA SURFACE TEMPERATURES. SEE THE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR ADDITIONAL DETAILS. DOWNGRADED TROPICAL DEPRESSION KRISTY WAS CENTERED NEAR 25.1N 119.0W AT 0300 UTC MOVING NW OR 300 DEG AT 8 KT WITH MAXIMUM SUSTAINED WINDS OF 30 KT WITH GUSTS TO 40 KT AND MINIMUM PRESSURE OF 1008 MB. LATEST SATELLITE SHOWS A GRADUAL DETERIORATING CLOUD PATTERN WITH THE DEPRESSION...HOWEVER THE CYCLONIC CIRCULATION IS SEEN ON THE E EDGE OF A LARGE AREA OF STRATOCUMULUS CLOUD DECK TO ITS W. CONVECTION IS RAPIDLY WEAKENING ...AND WIDELY SCATTERED SHOWERS AND TSTMS ARE WITHIN 120 NM OF THE CENTER IN THE NW QUADRANT. THE DEPRESSION IS FORECAST TO WEAKENED TO A REMNANT LOW IN ABOUT 12 HRS AS OT MOVES INTO A MORE STABLE ENVIRONMENT AND OVER COOLER SE SURFACE TEMPERATURES. 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 SOUTHERN COAST OF COSTA RICA TO 10N95W TO 08N108W TO 12N118W WHERE IT ENDS. IT THEN RESUMES AT LOW PRES 1010 MB NEAR 12N133W TO 08N140W. SCATTERED MODERATE TO STRONG CONVECTION IS S OF THE MONSOON TROUGH FROM 05N-09N E OF 86W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 75 NM OF A LINE FROM 06N91W TO 06N86W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF THE MONSOON TROUGH W OF 137W. ...DISCUSSION... A LONGWAVE UPPER RIDGE CONTINUES OVER MUCH OF THE EASTERN N PACIFIC STEMMING FROM AN UPPER ANTICYCLONE CENTERED AT 29N121W AND RIDGING NE TO WELL BEYOND 35N120W. AN UPPER RIDGE ALSO EXTENDS SW TO A SHARP CREST OVER THE DEEP TROPICS AT 12N139W. A MID/UPPER LAYER TROUGH PERSISTS OVER THE NW PORTION OF THE AREA WITH AN ASSOCIATED UPPER CYCLONE JUST NW OF THE AREA. 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 11N133W. SOME OF THE DEBRIS MOISTURE IS ADVECTED N ACROSS THE UPPER RIDGE AXIS BETWEEN 132W AND 144W WHILE IT EVAPORATES. VERY DRY AIR ALOFT DUE TO MODERATE TO STRONG SUBSIDENCE IS OBSERVED NW OF A LINE FROM SRN BAJA CALIFORNIA TO 12N136W. THE UPPER ANTICYCLONE IS EXPECTED TO TURN SE AND REACH THE CENTRAL BAJA PENINSULA ON MON. THE UPPER CYCLONE JUST NW OF THE AREA IS EXPECTED TO MOVE NE WITH THE MID/UPPER TROUGH EXTENDING S FROM THE CYCLONE SHIFTING TO W OF THE AREA ON MON THROUGH TUE. 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 NW MEXICO AND OVER SRN BAJA CALIFORNIA TO TROPICAL DEPRESSION KRISTY...WITH THE UPPER TROUGH STILL CONTINUING SW THROUGH 18N125W...AND TO NEAR TROPICAL STORM LANE. A BROAD INVERTED UPPER TROUGH IS NOTED OVER THE DEEP TROPICAL PACIFIC TO THE S OF 17N BETWEEN 100W-115W. AN UPPER ANTICYCLONE IS QUASI-STATIONARY OVER THE NW CARIBBEAN AT 17N86W...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 STREAMING WWD IS NOTED TO THE N OF 05N BETWEEN 80W AND 105W... AND ALSO TO THE S OF 15N BETWEEN 105W AND 130W. SOME OF THE DEBRIS MOISTURE FROM TROPICAL CYCLONE KRISTY CONCENTRATES IN A PLUME THAT TURNS NEWD ACROSS NORTHEASTERN ALONG THE SRN PERIPHERY OF THE UPPER TROUGH THERE...THEN FANS OUT AS IT MERGES WITH ADDITIONAL MOISTURE OVER W TEXAS. ELSEWHERE AT THE SURFACE...A BROAD RIDGE COVERS THE AREA N OF ABOUT 19N AND TO THE W OF 122W. THE TIGHT PRES GRADIENT OVER SOUTHEASTERN MEXICO HAS SLACKENED...ALLOWING FOR THE GULF OF TEHUANTEPEC NLY WINDS OF 20-25 KT TO DIMINISH TO AROUND 20 KT. THESE WINDS ARE EXPECTED TO DIMINISH FURTHER TO LESS THAN 20 KT DURING THE OVERNIGHT HRS. THE RIDGE WILL WEAKEN OVER THE CENTRAL PORTION OF THE AREA THROUGH THE NEXT 48 HRS AS LANE TRACKS TO THE NW. $$ AGUIRRE