000 AXPZ20 KNHC 140354 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED JAN 14 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0230 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...THE PRESSURE GRADIENT REMAINS STRONG BETWEEN RIDGING EXTENDING FROM THE GREAT LAKES REGION SOUTHWESTWARD THROUGH NE MEXICO TOWARD THE ISTHMUS OF TEHUANTEPEC...AND A STALLED FRONTAL ZONE EXTENDING NORTH TO SOUTH THROUGH THE CENTRAL BAY OF CAMPECHE. WINDS TO MINIMAL GALE FORCE WERE DEPICTED LATE THIS MORNING ACROSS THE GULF OF TEHUANTEPEC N OF 15.5N IN ASCAT DATA...AND ARE EXPECTED TO CONTINUE THROUGH THE END OF THE WEEK AND INTO THE UPCOMING WEEKEND. NOCTURNAL DRAINAGE FLOW OFF THE MOUNTAINS DURING THE LATE NIGHT AND EARLY MORNING HOURS IS EXPECTED TO ENHANCE THIS FLOW TO 35 TO 4O KT TONIGHT...WITH MAXIMUM SEAS BUILDING TO 14 FT. GAP WINDS ACROSS THE GULF AREA ARE THEN EXPECTED TO REMAIN AT MINIMAL GALE FORCE THROUGH THE REST OF THE WEEK...WITH DOWNSTREAM SEAS IN THE 8-12 FT RANGE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH 07N74W TO 09.5N85W TO 04.5N93W...WHERE IT TRANSITIONS TO ITCZ...CONTINUING ON TO 03.5N96W TO 08.5N115W... WHERE IT IS BROKEN...THEN RESUMES FROM 07N123W TO 09N135W TO 07.5N140W. ISOLATED TO SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 240 NM SE OF TROUGH BETWEEN 84W AND 89W. ...DISCUSSION... A SHARP UPPER LEVEL TROUGH CONTINUES ACROSS THE AREA THIS EVENING...NOW ALONG 126W/127W...WITH BASE ALONG 06N...SHIFTING SLOWLY EASTWARD. A SURFACE TROUGH EXTENDS ALONG 121W/122W FROM FROM 06.5N117W TO 12N122W...WHERE SCATTERED TO NUMEROUS STRONG CONVECTION IS OCCURRING WITHIN 360 NM NE OF THE TROUGH. PRECIPITABLE WATER IMAGERY SHOWS ABUNDANT TROPICAL MOISTURE MAXIMUMS CONVERGING ALONG THE ITCZ BETWEEN THE SURFACE TROUGH AND 105W. MOISTURE SHOULD REMAIN PLENTIFUL ACROSS THIS AREA FOR THE NEXT FEW DAYS. THIS REGION SHOULD REMAIN CONVECTIVELY ACTIVE THROUGH THE FORECAST PERIOD AS THE UPPER TROUGH SHIFTS SLOWLY EASTWARD TO 120W...AIDED BY STRONG DYNAMICS ASSOCIATED WITH AN ACTIVE JETSTREAM MOVING THROUGH THE BASE OF THE TROUGH. A NARROW SUBTROPICAL RIDGE EXTENDS FROM WEAKENING 1023 MB HIGH PRESSURE NEAR 37N126W THROUGH 22N122W TO 20N107W. THE PRESSURE GRADIENT REMAINS SUFFICIENT BETWEEN THE RIDGE AND THE SURFACE TROUGH MENTIONED ABOVE TO PRODUCE AND AREA OF STRONG NE TO E TRADEWINDS FROM 10N TO 15N BETWEEN 117W AND 124W. THE RIDGE IS EXPECTED TO WEAKEN DURING THE NEXT TWO DAYS...SLOWLY DIMINISHING THE PRESSURE GRADIENT. HOWEVER FRESH TO STRONG TRADEWINDS FROM 11N TO 15N ARE EXPECTED TO SHIFT SLOWLY EASTWARD IN TANDEM WITH THE UPPER TROUGH...FUELING THE ACTIVE EXPECTED CONVECTION MENTIONED ABOVE. SEAS ACROSS THIS AREA WILL REMAIN IN THE 8-9 FEET RANGE...WITH MIXED NW SWELL. A WEAK COLD FRONT HAS BEGUN TO ENTER THE FAR NW CORNER OF THE AREA THIS EVENING...FROM 30N139.5W TO 29.5N140W...AND IS EXPECTED TO MOVE SE ACROSS NW WATERS AND DISSIPATE FROM 30N135W TO 28N136W WEDNESDAY MORNING. SOUTHERLY WINDS 20-25 KT ARE OCCURRING AHEAD OF THE FRONT N OF 29N E OF FRONT TO 133W...WHERE SEAS ARE 8 TO 11 FT WITH NW SWELL. SCATTERED MODERATE CONVECTION ALOFT WAS OCCURRING E OF THE FRONT...N OF 24.5N BETWEEN 132W AND 136W. SEAS WILL QUICKLY BUILDING TO 12-14 FT IN NW SWELL BEHIND THE FRONT OVERNIGHT ACROSS THE FAR NW WATERS. THIS NW SWELL WILL CONTINUE TO SEND SEAS OF 8 FT OR GREATER SOUTHEASTWARD INTO THE FORECAST AREA...SPANNING THE AREA W OF 126W N OF A LINE FROM 15N126W TO 9N140W BY EARLY THURSDAY MORNING. GAP WINDS... GULF OF PAPAGAYO...TRADE WINDS IN THE SW CARIBBEAN CONTINUE TO FUNNEL THROUGH NORTHERN COSTA RICA AND ACROSS THE GULF OF PAPAGAYO. FRESH E-NE WINDS IN PLACE THIS EVENING WILL INCREASE TO 20-25 KT OVERNIGHT AND AGAIN WED NIGHT...THROUGH THE MORNING HOURS...PEAKING DURING THE MAXIMUM NOCTURNAL DRAINAGE FLOW. GULF OF CALIFORNIA...AN UPPER LOW OVER THE U.S. GREAT BASIN WILL MAKE ITS WAY S TO THE ARIZONA/MEXICO BORDER WED BEFORE SHEARING EASTWARD THU. AT THE SURFACE...THE PRESSURE GRADIENT WILL BUILD BETWEEN LEE SIDE TROUGHING ALONG THE W SLOPES OF THE SIERRA MADRE OCCIDENTAL AND INCREASED RIDGING OVER THE GREAT BASIN IN THE WAKE OF THE SYSTEM WED AND THU. A FRESH N BREEZE IS EXPECTED OVER THE NORTHERN GULF OF CALIFORNIA WED...WITH AN OCCASIONAL STRONG BREEZE THROUGH FRI MORNING. $$ STRIPLING