000 AXPZ20 KNHC 290326 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT OCT 29 2011 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 0130 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 10N83W TO 07N95W TO 12N125W TO 10N133W. THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM 10N133W TO 09N140W. SCATTERED MODERATE CONVECTION WAS N OF 04N E OF 84W AND N OF 09N BETWEEN 84W AND 88W...WITHIN 120 NM N OF AXIS BETWEEN 117W AND 120W...AND N OF AXIS TO 21N BETWEEN 121W AND 130W. ...DISCUSSION... AN UPPER LOW IS OVER THE NW PORTION OF THE AREA NEAR 28N135W. THIS LOW IS PART OF A MEAN TROUGH THAT EXTENDS W TO THE HAWAIIAN ISLANDS. ENERGY OVER THAT WESTERN PORTION OF THE TROUGH WILL SINK SOUTHWARD OVER THE NEXT FEW DAYS AND EJECT THE UPPER LOW NORTHWARD AND OUT OF THE FORECAST AREA. UNTIL THEN...THE MAIN IMPACT ON THE SENSIBLE WEATHER OVER THE PACIFIC WILL BE CLOUDS AND SHOWERS OVER N CENTRAL WATERS. UPPER LEVEL DIFFLUENCE AND SHOWER ACTIVITY ARE CURRENTLY MOST PREVALENT IN THE REAR RIGHT QUADRANT OF THE 50-60 KT SOUTHERLY JET ON THE SE SIDE OF THE UPPER LOW...WITH SCATTERED MODERATE CONVECTION N OF THE MONSOON TROUGH TO 21N BETWEEN 121W AND 130W. WATER VAPOR IMAGERY SHOWS THE MOISTURE TRANSPORT ALOFT FROM THE TROPICS INTO THE LOW WITH DRY AIR WRAPPING AROUND THE WESTERN AND SOUTHERN SIDES OF THE LOW. CIRRUS ON THE E SIDE OF THE LOW IS MOVING ACROSS BAJA CALIFORNIA. THE 1024 MB SUBTROPICAL HIGH LIES NEAR 36N132W AND EXTENDS A RIDGE AXIS SE TO 20N117W. THE PRES GRADIENT BETWEEN THE SW SIDE OF THE RIDGE AND THE ITCZ/MONSOON TROUGH IS STRONG ENOUGH TO YIELD FRESH TRADE WINDS OVER WATERS W OF 125W BETWEEN 12N AND 20N. THESE TRADES WILL VARY LITTLE OVER THE NEXT FEW DAYS AS THE SUBTROPICAL HIGH POSITION AND STRENGTH REMAINS MOSTLY UNCHANGED. THE 1420 UTC ASCAT PASS SHOWED FRESH SW FLOW S OF THE MONSOON TROUGH OVER THE FAR SE PORTION OF THE AREA S OF PANAMA. THESE WINDS ARE EXPECTED TO CONTINUE FOR THE NEXT DAY OR TWO AS THE PRES GRADIENT REMAINS TIGHT BETWEEN TROUGHING OVER THE WESTERN CARIBBEAN AND RIDGING S OF THE EQUATOR IN THE EASTERN PACIFIC. THE STRENGTH OF THE WINDS HERE WILL LARGELY BE TIED TO THE STRENGTH OF THE TROUGHING IN THE CARIBBEAN. SCATTERED MODERATE CONVECTION IS NOTED NEAR THE COAST OF CENTRAL AMERICA AND COLOMBIA IN THE SECTION ABOVE. THIS CONVECTION EXTENDS INLAND OVER MUCH OF PANAMA...COSTA RICA...NICARAGUA AND INTO THE GULF OF FONSECA AREA. THIS AREA LIES UNDER UPPER LEVEL DIFFLUENCE ASSOCIATED WITH A RIDGE AXIS THAT EXTENDS TO AN ANTICYCLONE OVER EASTERN CUBA AND WITHIN THE REGION OF HIGHEST PRECIPITABLE WATER VALUES IN THE FORECAST AREA. PRECIPITATION SHOULD CONTINUE HERE FOR MUCH OF THE PERIOD. A COLD FRONT IS MAKING ITS WAY THROUGH EASTERN MEXICO AND THE WESTERN GULF OF MEXICO. HIGH PRES BEHIND THE FRONT WILL MIGRATE EASTWARD FROM THE U.S. FOUR CORNER STATES OVERNIGHT AS THE FRONT CONTINUES E. FRESH NW TO N WINDS ARE BLOWING ACROSS THE GULF OF CALIFORNIA ACCORDING TO THE EXPERIMENTAL 1737 UTC ASCAT 25 KM COASTAL WINDS. THESE WINDS ARE FORECAST TO DIMINISH BEFORE SUNRISE AS HIGH PRES OVER THE FOUR CORNERS STATES WEAKENS AND THE PRES GRADIENT RELAXES OVER THE REGION. GAP WINDS...THE AFOREMENTIONED COLD FRONT IS CURRENTLY MAKING ITS WAY INTO THE CHIVELA PASS. SUSTAINED NORTHERLY WINDS AT MINATITLAN AND TUXTLA GUTIERREZ HAVE INCREASED TO 20 KT DURING THE PAST FEW HOURS WITH GUSTS TO GALE FORCE. THESE WINDS ARE BELIEVED TO BE BLEEDING INTO THE GULF OF TEHUANTEPEC AND WILL RAPIDLY INCREASE TO GALE FORCE THERE TONIGHT AND CONTINUING THROUGH SUN MORNING. EXPECT WINDS TO INCREASE TO 40 KT BY SAT EVENING WITH SEAS BUILDING TO AROUND 14 FT. LOOKING AHEAD...GALE CONDITIONS ARE EXPECTED TO DIMINISH BRIEFLY ON SUN...WITH A RECURRENCE OF GALES ON MON AS ANOTHER SPOKE IN THE EASTERN NORTH AMERICAN MEAN TROUGH SWINGS THROUGH THE GULF OF MEXICO AND REINFORCES THE HIGH PRESSURE BEHIND THE FRONT OVER THE NORTHERN GULF OF MEXICO COASTAL PLAIN. $$ SCHAUER