000 AXPZ20 KNHC 182153 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC MON FEB 18 2013 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH NOT DISCERNIBLE FOR 1800 UTC ANALYSIS. ITCZ EXTENDS FROM 06N87W TO 02N101W TO 05.5N120W TO 07N140W. ISOLATED TO SCATTERED CONVECTION NOTED WITHIN 90 NM EITHER SIDE OF AXIS BETWEEN 87W AND 94W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 270 NM N OF AXIS W OF 135W. ...DISCUSSION... UPPER LEVEL TROUGHING CONTINUES TO DOMINATE N AND NW PORTIONS OF THE AREA THIS AFTERNOON...AS A STRONG SHORTWAVE WAS MOVING SE INTO THE REGION...THROUGH 36N130W TO 29N134W...AND WILL SOON COME INTO PHASE WITH NE PORTIONS OF AN ELONGATED MIDDLE TO UPPER TROPOSPHERIC TROUGH EXTENDING FROM SOUTHERN CALIFORNIA TO 27N128W TO 26N147W THEN DIVING SW AND S ACROSS THE HAWAIIAN ISLANDS. A BROAD AND WEAKENED UPPER JET OF 80-100 KT RESIDES S OF THE ELONGATED UPPER TROUGH AND CONTINUES TO TRANSPORT HIGH CLOUDS AND UPPER LEVEL MOISTURE FROM THE TROPICAL E CENTRAL PACIFIC NE ACROSS BAJA CALIFORNIA AND N MEXICO. UPPER LEVEL RIDGING S AND SE OF THE JET HAS FLATTENED THE PAST 24 HOURS...YIELDING ZONAL UPPER LEVEL FLOW GENERALLY N OF 17N AND E OF 110W... ACROSS MEXICO AND THE GULF OF MEXICO. THIS BROAD FLAT RIDGE IS CURRENTLY ANCHORED ON TWO ANTICYCLONES...ONE OVER THE S CENTRAL CARIBBEAN...AND A SECOND NEAR 08N122W...WITH A BROAD TROPICAL UPPER TROUGH IN BETWEEN...CENTERED ALONG 103W S OF 16N...EXTENDING JUST ACROSS THE EQUATOR. AT THE SURFACE...THE CENTRAL PACIFIC RIDGE DOMINATES NW PORTIONS...CENTERED ON A 1036 MB HIGH NEAR 39N155W AND EXTENDING SE TO 25N114W. A BROAD ZONE OF FRESH TO STRONG NE TRADES RESIDE N OF THE ITCZ FROM 09N TO 22N W OF 134W AND FROM 10N TO 15N BETWEEN 128W AND 134W...WHERE SEAS ARE RUNNING 8 TO 12 FT IN MIXED NE AND NW SWELL. A COLD FRONT WILL ENTER NE PORTIONS BETWEEN 24 AND 48 HOURS...RIDING OVER THE RIDGE AND DROPPING SE ACROSS THE FAR NE PACIFIC...AND INTO BAJA CALIFORNIA. STRONG NWLY WINDS BEHIND THE FRONT WILL RAISE SEAS 10-15 FT IN NW SWELL N OF 26N BY WED AFTERNOON. THE CENTRAL PACIFIC HIGH WILL SHIFT SLIGHTLY SE BEHIND THE FRONT...AND STRENGTHEN THE PRES GRADIENT TO ITS S...AND ACT TO EXPAND THE AREA OF STRONG NE TRADES ON WED. NLY WINDS THROUGH THE GULF OF TEHUANTEPEC HAVE DECREASED TO BELOW 20 KT ACROSS RETURN SOUTHERLY WIND FLOW HAS DEVELOPED ACROSS MUCH OF THE GULF OF MEXICO. HOWEVER...STRONG NE WINDS CONTINUE THROUGH AND WELL DOWNWIND OF THE GULF OF PAPAGAYO THIS AFTERNOON...TO NEAR 101W...WHERE SEAS 9-12 FT PREVAIL. A 1550 UTC ASCAT PASS ACROSS THIS AREA DEPICTED THE PLUME OF FRESH TO STRONG NE WINDS THERE...WITH A SMALL AREA AROUND 30 KT CONTINUING CENTERED NEAR 09N88W. WINDS THROUGH THIS ZONE HAVE SINCE DIMINISHED TO 20-25 KT AND WILL GRADUALLY WEAKEN THROUGH WED...BUT SHOULD PULSE AGAIN TO 25-30 KT NEAR 10N87.5W TONIGHT DURING THE TYPICAL NOCTURNAL MAXIMUM. FRESH TO LOCALLY STRONG NORTHERLY FLOW IS ALSO SPILLING ACROSS PANAMA AND INTO THE ADJACENT FAR EASTERN PACIFIC...EXTENDING S-SW TO NEAR 03N82W...WHERE SEAS HAVE BUILT 6-8 FT. THIS NORTHERLY FLOW IS EXPECTED TO DIMINISH BELOW 20 KT BY TUE AFTERNOON AS THE WIND FLOW ACROSS THE W AND NW CARIBBEAN RETURNS TO A MORE TYPICAL EASTERLY DIRECTION. $$ STRIPLING