000 AXPZ20 KNHC 030842 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT NOV 03 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 0830 UTC. ...SPECIAL FEATURE... TROPICAL STORM ROSA CENTERED NEAR 12.6N 119.7W AT 0900 UTC MOVING WEST AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WINDS 40 KT GUSTS TO 50 KT. PERSISTENT WESTERLY SHEAR CONTINUES TO DISPLACE THE CONVECTION E OF THE LOW-LEVEL CENTER. NUMEROUS MODERATE TO STRONG CONVECTION LOCATED WITHIN 120 NM E SEMICIRCLE. THE STORM IS EXPECTED TO DRIFT SLOWLY W-NW AND WEAKEN THROUGH MON...BECOMING A POST-TROPICAL REMNANT LOW LATE SAT TO EARLY SUN MORNING. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/ WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 09N85W TO 08N95W TO 11N110W... THEN RESUMES W OF T.S. ROSA FROM 12N120W TO 10N127W. THE ITCZ EXTENDS FROM 10N127W TO 09N133W TO 11N140W. SCATTERED MODERATE CONVECTION WITHIN 60 NM S OF TROUGH BETWEEN 89W AND 102W. SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 14N TO 16N BETWEEN 104W AND 111W. SCATTERED MODERATE CONVECTION WITHIN 90 S OF BOUNDARY BETWEEN 121W AND 131W. ...DISCUSSION... UPPER PATTERN IS BECOMING MORE AMPLIFIED N OF 20N AS A SHORT WAVE TROUGH PUSHES SE THROUGH 125W...EVENTUALLY SWINGING EASTWARD THROUGH BAJA...AHEAD OF A MID TO UPPER LEVEL RIDGE SET UP ALONG 140W. AN ASSOCIATED 1019 MB SURFACE HIGH IS CENTERED NEAR 28N131W. ALTHOUGH GLOBAL MODEL CONSENSUS SHOWS THE SURFACE HIGH SHIFTING A LITTLE FARTHER NORTH TO 30N136W THROUGH 24 HOURS...THE SURFACE HIGH IS EXPECTED TO STRENGTHEN AS THE UPPER RIDGE BUILDS. THIS WILL ENHANCE FRESH TO STRONG TRADE WIND FLOW S OF THE AREA MAINLY FROM 12N TO 20N W OF 125W...WITH SEAS BUILDING TO 9 FT THROUGH 48 HOURS. MEANWHILE STRONG WESTERLY SHEAR ALOFT SUPPLIED BY THE DEEPENING TROUGH ALONG 125W N OF 20N CONTINUES TO WEAKEN TROPICAL STORM ROSA. THE STORM WILL DIMINISH TO A DEPRESSION THROUGH 24 HOURS BEFORE BECOMING A REMNANT LOW BY 48 HOURS...AND DISSIPATING ALTOGETHER ALONG THE MONSOON TROUGH THROUGH 96 HOURS. ANOTHER LOW PRES TO THE EAST OF ROSA LOOKS A LITTLE BETTER ORGANIZED THIS MORNING NEAR 14N110W. THE LOW IS EXPECTED TO DRIFT A LITTLE MORE TO THE NE DRIVEN BY MODEST WSW STEERING FLOW AND SHEAR ALOFT. THE PRES GRADIENT WILL TIGHTEN ALONG THE NE QUADRANT OF THIS LOW OVER THE NEXT COUPLE OF DAYS AS IT MOVES TOWARD HIGHER PRES FARTHER TO THE EAST. SE WINDS TO 20 KT WITH FULLY DEVELOPED SEAS TO 8 FT CAN BE EXPECTED WITHIN 120 NM NE OF LOW WITHIN 24 HOURS...WITH SEAS BUILDING TO 9 FT IN SE SWELL BY 48 HOURS. THE COMBINATION OF CONVERGENT SW FLOW INTO THE MONSOON TROUGH ALONG WITH WSW EXHAUST FLOW ALOFT ARE AIDING SCATTERED CONVECTION WITHIN 90 NM OF THE LOW AND IN A LARGE AREA N OF 13N BETWEEN 95W AND 110W. AN ASCAT PASS FROM 1630 UTC YESTERDAY INDICATED FRESH GAP FLOW HAS SET UP THROUGH THE GULF OF TEHUANTEPEC...DUE TO DENSER AIR ASSOCIATED WITH HIGH PRES OVER THE GULF OF MEXICO SEEPING THROUGH THE ISTHMUS. THIS WILL REMAIN 20 KT OR LESS THROUGH SUN AND FAVOR EARLY MORNING HOURS. A SOMEWHAT STRONGER PUSH OF GAP WINDS WILL BEGIN LATE MON AS THE HIGH PRES IS PUSHED SOUTHWARD AHEAD OF A COLD FRONT MOVING INTO THE GULF. THE LATEST GFS SOLUTION SHOWS 30M WINDS TO 25 KT...COMING INTO BETTER AGREEMENT WITH THE EARLIER ECMWF. LOOKING AHEAD...TUE MAY SEE A BETTER CHANCE OF STRONG GAP FLOW IN TEHUANTEPEC AS THE COOLER AND DRIER AIR PUSHES S THROUGH THE WESTERN GULF OF MEXICO. $$ CHRISTENSEN