000 AXPZ20 KNHC 142227 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...NORTHERLY WIND FLOW BETWEEN A STALLED FRONTAL BOUNDARY THAT RUNS NORTH TO SOUTH ACROSS THE BAY OF CAMPECHE...AND RIDGING EXTENDING NORTH TO SOUTH ALONG THE NORTHEASTERN MEXICAN COAST IS FUNNELING THROUGH THE ISTHMUS OF TEHUANTEPEC. THIS PATTERN IS MAINTAINING STRONG NORTHERLY WINDS W OF THE FRONT IN THE GULF OF MEXICO THAT CONTINUE TO SPILL THROUGH THE CHIVELA PASS AND ACCELERATE TO 25-35 KT ACROSS THE GULF OF TEHUANTEPEC AND EXTENDING SOME 100-150 NM DOWNSTREAM. THIS RIDGE WILL WEAKEN SLIGHTLY OVER THE NEXT 24 HOURS...AND GALE FORCE WINDS ARE EXPECTED TO DIMINISH TO 20-30 KT BY THU MORNING. HOWEVER...GLOBAL MODELS SHOW THE RIDGE STRENGTHENING AGAIN ACROSS W TEXAS AND SOUTHWARD ACROSS EASTERN MEXICO...WHICH SHOULD INCREASE WINDS ACROSS TEHUANTEPEC TO GALE FORCE AGAIN THU EVENING...THEN INCREASE FURTHER TO 30-40 KT OVERNIGHT THU THROUGH FRI NIGHT. SEAS WILL FLUCTUATE AT 8 TO 11 FT ACROSS THE GULF OF TEHUANTEPEC THROUGH THU THEN INCREASE TO 9-14 FT THU NIGHT THROUGH FRI. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 07N78W TO 08N83W TO 06N90W...THEN ITCZ FROM 06N90W TO 04N96W...TO 1010 MB LOW CENTER NEAR 09N114W...TO 08N130W TO 10N135W. SCATTERED STRONG CONVECTION NOTED FROM 04N TO 05N BETWEEN 85W AND 87W. NUMEROUS STRONG CONVECTION NOTED FROM 07N TO 14N BETWEEN 110W AND 115W. ...DISCUSSION... A SHARP MIDDLE TO UPPER LEVEL TROUGH EXTENDS NEARLY NORTH TO SOUTH ACROSS THE AREA N OF 06N BETWEEN 120W AND 130W...WITH A 55- 65 KT JETSTREAM PASSING THROUGH THE BASE. BROAD UPPER RIDGES OCCURRING ON BOTH SIDES OF THIS TROUGH ARE ALLOWING FOR ONLY A SLOW EASTWARD SHIFT OF THE TROUGH. SHARP TURNING WITHIN THE BASE OF THE TROUGH S OF 20N CONTINUES TO WORK DOWNWARD THROUGH THE ATMOSPHERE AND NEARLY TO THE SURFACE...WHERE A SHORT SURFACE TROUGH WAS ALONG 125W S OF 13N...AND A 1010 MB SURFACE LOW CENTER WAS SUGGESTED BY SATELLITE IMAGERY NEAR 09N114W. NUMEROUS STRONG CONVECTION WAS OCCURRING E OF THE LOW...FROM 07N TO 14N BETWEEN 110W AND 115W. THE MIDDLE TO UPPER TROUGH IS FORECAST TO SHIFT SLOWLY EASTWARD THROUGH FRI NIGHT...AND REORGANIZE...WITH A CUT OFF LOW DEVELOPING NEAR 13N117W BY SUN MORNING. AMPLE MIDDLE TO UPPER LEVEL ENERGY IS EXPECTED TO PERSIST ABOUT THE BASE OF THIS TROUGH...AND INTERACT WITH ABUNDANT LOW LEVEL MOISTURE TO MAINTAIN VERY ACTIVE CONVECTION EAST THROUGH SOUTHEAST OF THE UPPER TROUGH DURING THE NEXT FEW DAYS. THE SUBTROPICAL RIDGE EXTENDS FROM 1025 MB HIGH PRESSURE NEAR 33N124W THROUGH 25N120W TO 17N108W. THE PRESSURE GRADIENT HAS WEAKENED A BIT BETWEEN THE SUBTROPICAL RIDGE AND THE AFOREMENTIONED THE 1010 MB LOW PRESSURE CENTER. MIDDAY SCATTEROMETER DATA SHOW FRESH TO STRONG TRADE WINDS FROM 09N TO 17N BETWEEN 113W AND 122W. THE RIDGE WILL CONTINUE TO WEAKEN DURING THE NEXT TWO DAYS...RELAXING THE PRESSURE GRADIENT. TRADE WINDS ARE EXPECTED TO DIMINISH BELOW THE LEVEL OF A FRESH TO STRONG BREEZE ON THURSDAY AS A RESULT. THE ACCOMPANYING AREA OF SEAS 8 FEET OR GREATER WILL SHRINK SIGNIFICANTLY AS THE WINDS DROP OFF. A WEAKENING COLD FRONT PASSES THROUGH 30N132.5W TO 26.5N140W... ACROSS THE NORTHWESTERN PORTION OF THE FORECAST AREA. THE LATEST SCATTEROMETER DATA SHOW A FRESH SOUTHERLY BREEZE JUST AHEAD OF THE FRONT. SEAS HIGHER THAN 8 FEET IN NW SWELL CONTINUE OUT AHEAD OF THE FRONT...BUT THE HIGHEST SEAS...11-13 FT...LOCATED BEHIND THE FRONT. THE NW SWELL WILL CONTINUE TO SEND SEAS OF 8 FT OR GREATER SOUTHEASTWARD INTO THE FORECAST AREA. GAP WINDS... GULF OF PAPAGAYO...FRESH TO STRONG TRADEWINDS ACROSS THE WEST AND SOUTHWESTERN CARIBBEAN SEA CONTINUE TO FUNNEL THROUGH NORTHERN COSTA RICA AND ACROSS THE GULF OF PAPAGAYO. FRESH TO STRONG EAST-TO-NORTHEAST WINDS OCCURRING THIS MORNING ARE EXPECTED TO DIMINISH TO 15-20 KT EARLY THIS EVENING...THEN INCREASE AGAIN OVERNIGHT THROUGH THU MORNING TO 15-25 KT DURING THE PERIOD OF MAXIMUM NOCTURNAL DRAINAGE FLOW. WINDS AND SEAS WILL BRIEFLY DIMINISH AGAIN THU DURING THE AFTERNOON AND EARLY EVENING HOURS. GULF OF CALIFORNIA...AN UPPER LOW OVER ARIZONA MOVING SLOWLY SE TODAY WILL BECOME SHEARED AND FORCED EASTWARD INTO TEXAS ON THURSDAY. 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 TODAY AND THU. SCATTEROMETER DATA EARLY THIS AFTERNOON SHOWED NW TO N WINDS 15-20 KT OCCURRING ACROSS THE NORTHERN GULF OF CALIFORNIA...AND OCCASIONAL INCREASES IN WINDS N OF 28N MAY OCCUR DURING THE NEXT DAY OR SO. $$ STRIPLING