000 AXPZ20 KNHC 121020 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT DEC 12 2015 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 0900 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A WEAK TROUGH EXTENDS FROM 09.5N83.5W TO 06.5N93W TO LOW PRES NEAR 08N97.5W 1010 MB TO 09N109W. SECOND WEAK TROUGH EXTENDS FROM LOW PRES NEAR 12N114W 1008 MB TO 06N122W TO 03.5N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 150 NM N AND 180 NM S OF TROUGH BETWEEN 96W AND 109W. WIDELY SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 150 NM N AND 210 NM S OF TROUGH W OF 114W. SCATTERED MODERATE ELEVATED CONVECTION FROM 15N TO 24N E OF 108W TOMEXICAN COAST. TO MEXICAN COAST. ...DISCUSSION... A MIDDLE TO UPPER LEVEL LOW REMAINS CUT OFF FROM THE MEAN UPPER FLOW THIS MORNING...LOCATED NEAR 16N118W AND HAS BEGUN TO SHIFT E...AHEAD OF A SHARP UPPER TROUGH SWEEPING SE ACROSS NE PORTIONS OF THE DISCUSSION AREA. THIS DEEP LAYERED CYCLONIC CIRCULATION HAS AIDED IN DRAWING TROPICAL MOISTURE FROM THE DEEP TROPICS NORTH AND NORTHEASTWARD TO PACIFIC COASTAL SECTIONS OF MEXICO FROM GUERRERO TO SOUTHERN PORTIONS OF SINALOA. A 1008 MB SURFACE LOW PRESSURE CENTER ACROSS THIS REGION WAS LOCATED NEAR 12N114W AND WAS INITIATING SCATTERED MODERATE TO STRONG CONVECTION WITHIN 300 NM NE AND 120 NM SE QUADRANTS. ADDITIONAL SMALL CLUSTERS OF ELEVATED CONVECTION WERE OCCURRING ACROSS THE COASTAL WATERS OF MEXICO FROM 15N TO 24N E OF 108W AND MOVING ASHORE ALONG THE MEXICAN COAST. ACTIVE CONVECTION IS EXPECTED TO CONTINUE ACROSS THIS AREA THROUGH TONIGHT AS THE UPPER LOW SHIFTS E TO ALONG 110W AND THE SURFACE LOW MOVES NE AND DISSIPATES. A COLD FRONT CONTINUES TO MOVE SOUTHEASTWARD ACROSS THE AREA THIS MORNING...ANALYZED FROM MAINLAND MEXICO NEAR 27.5N111W ACROSS THE GULF OF CALIFORNIA AND BAJA PENINSULA TO 22N120W TO 21.5N140W. A 1030 MB SURFACE HIGH BEHIND THE FRONT IS CENTERED NEAR 33N141W AND WILL CONTINUE TO DRIVE THE FRONT SE THROUGH THE WEEKEND...REACHING THE SOUTHERN GULF OF CALIFORNIA AND CABO SAN LUCAS TO 15.5N127W TO 17N140W THIS EVENING...THEN REACHING LAS ISLAS TRES MARIAS TO 19.5N106W TO 12N127W SUNDAY EVENING BEFORE IT BECOMES ILL DEFINED. FRESH TO STRONG N TO NE WINDS ARE BEHIND THE FRONT AND ARE COMBINING WITH VERY LARGE NW SWELL TO PRODUCE SEAS OF 10 TO 19 FT...WITH HIGHEST SEAS RECENTLY DEPICTED BY ALTIMETER DATA N OF 28N AND E OF 128W. SEAS HAVE BUILT TO 8 FT AS FAR SOUTHEAST AS 10N113W ASSOCIATED WITH THIS LARGE NW SWELL...AND WILL CONTINUE TO PROPAGATE SOUTHEASTWARD THROUGH THE WEEKEND AND IMPACT COASTAL ZONES OF CENTRAL AND SOUTH AMERICA. MARINE INTERESTS ACROSS THE REGION...ESPECIALLY ALONG THE BAJA CALIFORNIA COAST AND NEARBY ISLANDS SHOULD EXERCISE CAUTION. THE LEADING EDGE OF THIS SWELL...WITH PERIODS IN THE 18-20 SECONDS RANGE...WILL REACH THE SOUTHERN TIP OF THE BAJA CALIFORNIA PENINSULA EARLY SAT AND CABO CORRIENTES MEXICO BY SAT EVENING. FRESH TO STRONG NE WINDS WERE NOTED BY RECENT SCATTEROMETER PASSES SOUTH OF THE FRONT TO 07N W OF 124W. THESE WINDS ARE EXPECTED TO EXPAND OVER MUCH OF THE AREA FROM 11N-21N W OF 122W THROUGH SAT AS HIGH PRESSURE CONTINUES TO BUILD. THE HIGH PRESSURE CENTER N OF THE AREA IS FORECAST TO WEAKEN SUN AS A NEW COLD FRONT MOVES INTO N PORTIONS OF THE AREA...WITH THE AREA OF TRADE WINDS SHRINKING TO W OF 130W AS A RESULT. GAP WINDS... GULF OF PAPAGAYO...A SURFACE RIDGE OVER THE GULF OF MEXICO WILL STRENGTHEN OVERNIGHT. THIS WILL INCREASE THE PRESSURE GRADIENT BETWEEN THE RIDGE AND THE MONSOON TROUGH TO THE S OF THE GULF OF PAPAGAYO. THE INCREASED PRESSURE GRADIENT COUPLED WITH NOCTURNAL DRAINAGE FLOW SHOULD ALLOW FOR A FRESH TO STRONG E-NE BREEZE THROUGH THE GULF OF PAPAGAYO TO 88W DURING THE EARLY MORNING HOURS SAT. THESE WINDS ARE FORECAST TO DIMINISH AFTER SUNRISE SAT AS THE DRIVING HIGH PRES SHIFTS NE INTO THE ATLC. GULF OF CALIFORNIA...WINDS BEHIND THE COLD FRONT MENTIONED ABOVE ARE PRODUCING STRONG WINDS INSIDE THE GULF OF CALIFORNIA N OF THE FRONT...WHERE RECENT ASCAT DATA SHOWED W TO NW WINDS 20-30 KT. THESE WINDS SHOULD QUICKLY SPREAD S BEHIND THE FRONT THROUGH NOON TODAY BEFORE BRIEFLY WEAKENING THIS AFTERNOON TO 15-20 KT...THEN INCREASE ACROSS SOUTHERN PORTIONS OF THE GULF BEHINDTHE FRONT TONIGHT AND SUNDAY....WHERE SEAS WILL BUILD TO6- 8 FT. $$ STRIPLING