000 AXPZ20 KNHC 160915 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI DEC 16 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0715 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 09N78W TO 09N87W TO 07N98W. THE ITCZ AXIS EXTENDS FROM 07N98W TO 08N105W TO 06N118W TO 07N129W TO 06N135W TO 07N140W. SCATTERED MODERATE CONVECTION LIES WITHIN 150 NM N AND 180 NM S OF AXIS E OF 87W...WITHIN 150 NM N AND 45 NM S OF AXIS BETWEEN 97W AND 104W AND WITHIN 120 NM N OF AXIS BETWEEN 128W AND 133W. ...DISCUSSION... AN UPPER CYCLONE DEEPENING OVER THE SW U.S. AND NW MEXICO WILL BE SLOW TO MOVE DURING THE NEXT FEW DAYS. AN ASSOCIATED FRONTAL TROUGH CURRENTLY LIES FROM 31N119W TO 29N124W. THIS TROUGH WILL CONTINUE SOUTHEASTWARD TODAY. SHOWERS AND NW WINDS TO 20 KT ASSOCIATED WITH THE CYCLONE WILL PRIMARILY IMPACT THE NORTHERN GULF OF CALIFORNIA AND BAJA CALIFORNIA NORTE...WITH WINDS EXPECTED TO DIMINISH BY SAT MORNING AFTER THE FRONTAL TROUGH AT THE SURFACE DISSIPATES. A WEAK UPPER LOW LIES NEAR 28N140W. THIS LOW IS EXPECTED TO UNRAVEL WITH ITS REMAINS MOVING EASTWARD AS A WEAK DEEP LAYER TROUGH APPROACHES IT FROM THE W TONIGHT. WHAT REMAINS OF THE LOW WILL BECOME CAPTURED IN THE FLOW AROUND THE SOUTHERN EDGE OF THE DEEP UPPER LOW OVER THE SW U.S./NW MEXICO ON SAT. A DISSIPATING COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED WEAKENING DEEP LAYER TROUGH WILL APPROACH NW WATERS SAT AND USHER IN A NEW ROUND OF NW SWELL...WITH SEAS REACHING 10-12 FEET OVERNIGHT SAT NIGHT GENERALLY IN THE AREA N OF 20N W OF 130W. THE FRONT WILL WEAKEN THE SUBTROPICAL HIGH PRES OVER NW WATERS AND CAUSE TRADE WINDS TO SHRINK WESTWARD OVER THE NEXT 24-48 HOURS. MOISTURE IS POOLED ALONG THE ITCZ/MONSOON TROUGH AXIS WITH PRECIPITABLE WATER VALUES HIGHEST ALONG THE EASTERN EDGE OF THE AXIS. UPPER LEVEL DIFFLUENCE BETWEEN 35-50 KT WESTERLY WINDS ALOFT S OF 02N AND THE REAR RIGHT QUADRANT OF A SOUTHWESTERLY UPPER JET TO THE N IS ENHANCING CONVECTION OVER PANAMA...COSTA RICA AND THE GULF OF PANAMA. THESE CONDITIONS ARE NOT EXPECTED TO CHANGE MUCH OVER THE NEXT FEW DAYS. GAP WINDS... GULF OF TEHUANTEPEC...THE FORECAST GUIDANCE AGREES ON BRINGING N TO NE WINDS TO GALE FORCE IN THE GULF OF TEHUANTEPEC BY SAT NIGHT. WHILE THERE IS NO STRONG...PROGRESSIVE COLD FRONT EXPECTED TO SWEEP THROUGH THE GULF OF MEXICO TO INCREASE WINDS THROUGH THE ISTHMUS OF TEHUANTEPEC...THE BUILDING PRES GRADIENT BETWEEN HIGH PRES PASSING SE OVER THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY AND LOWER PRES ALONG THE MONSOON TROUGH TO THE S WILL BE ENOUGH TO INITIATE GALE FORCE WINDS. LOOK FOR FRESH TO STRONG N WINDS BEGINNING TONIGHT TO PRECEDE THE GALE. GULF OF PAPAGAYO...THE BUILDING PRES GRADIENT OVER SOUTHERN MEXICO WILL EXTEND S TO THE GULF OF PAPAGAYO BY EARLY SAT MORNING WITH FRESH NE WINDS EXPECTED THERE. THESE WINDS WILL INCREASE TO STRONG AS HIGH PRES TO THE N SETTLES SOUTHEASTWARD OVER THE LOWER MISSISSIPPI VALLEY SAT INTO SUN. $$ SCHAUER