000 AXPZ20 KNHC 170929 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN APR 17 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS FROM 08N78W TO LOW PRES 1008 MB NEAR 06N93W TO 01N110W TO 01N120W TO 04N132W. SCATTERED MODERATE CONVECTION WAS FROM 05N TO 09N BETWEEN 90W AND 94W. SCATTERED MODERATE TO STRONG CONVECTION WAS FROM 03N TO 07N BETWEEN 129W AND 135W. ...DISCUSSION... ALOFT...AN UPPER TROUGH IS ENTERING THE NW WATERS EXTENDING FROM THE SAN FRANCISCO BAY AREA SW THROUGH 32N130W TO 25N140W. A 30-50 KT JET IS ADVECTING MAINLY MID TO UPPER LEVEL MOISTURE FROM THE DEEP TROPICS TO S CALIFORNIA WITHIN 300 NM E OF THE TROUGH AXIS. BROAD UPPER RIDGING IS TO THE E FROM THE GULF OF SANTA CATALINA THROUGH 24N130W TO 10N130W. VERY DRY AIR UNDER MODERATE TO STRONG SUBSIDENCE COVERS THE AREA FROM 10N-20N BETWEEN 120W-130W. ANOTHER UPPER TROUGH EXTENDS FROM THE N BAJA CALIFORNIA PENINSULA SW TO 10N123W. MID TO UPPER LEVEL MOISTURE IS BEING ADVECTED FROM THE ITCZ NE TO ACROSS CENTRAL MEXICO AHEAD OF THIS TROUGH. ELSEWHERE ALOFT...UPPER RIDGING DOMINATES THE SE PORTION FROM NW COLOMBIA NEAR 08N78W TO 14N115W. CONVECTION IS BEING ENHANCED ALONG THE ITCZ UNDER UPPER LEVEL DIFFLUENT FLOW S OF THE RIDGE AXIS. ANOTHER UPPER LEVEL RIDGE STRETCHES FROM 05N123W TO 13N140W WITH ADDITIONAL CLUSTERS OF CONVECTION BEING ENHANCED ALONG THE ITCZ S OF THIS RIDGE AXIS AS DESCRIBED IN THE ITCZ SECTION ABOVE. AT THE SURFACE...1008 MB LOW PRES IS EMBEDDED IN THE ITCZ CENTERED NEAR 06N93W. ASSOCIATED CONVECTION CONTINUES TO BECOME LESS ORGANIZED WITH CLOUD TOPS WARMING. THIS ACTIVITY IS DESCRIBED IN THE ITCZ SECTION ABOVE. GFS MODEL GUIDANCE CONTINUES TO COME MORE IN LINE WITH THE PREVIOUSLY MORE CONSERVATIVE ECMWF SOLUTION DRIFTING THE LOW NW DURING THE NEXT FEW DAYS WITH ONLY 5-10 KT WINDS AROUND THE CIRCULATION. SURFACE RIDGING EXTENDS FROM 1024 MB HIGH PRES NEAR 30N135W SE TO AROUND 18N116W. NW-N 20 KT WINDS EXIST W OF THE N BAJA CALIFORNIA PENINSULA WHERE THE PRES GRADIENT IS THE TIGHTEST. THESE WINDS WILL PERSIST WHILE SHRINKING SLIGHTLY IN COVERAGE DURING THE NEXT 48 HOURS. NW SWELL OF 8-10 FT COVERS THIS SAME AREA AND WILL GRADUALLY DECAY TO 8 FT BY 48 HOURS. OTHERWISE... MIXED NE AND NW SWELL TO 9 FT COVERS THE MAJORITY OF THE WATERS W OF 118W EXCEPT THE FAR NW PORTION. THIS SWELL WILL DECAY TO LESS THAN 8 FT THROUGH EARLY TUE. LONG PERIOD 19-21 SECOND CROSS-EQUATORIAL SW SWELL WILL SWEEP ACROSS THE NE PACIFIC BEGINNING EARLY IN THE WEEK. THIS SWELL WILL REACH FROM THE S CALIFORNIA AND MEXICAN COASTS AND SE ACROSS ALL OF THE CENTRAL AMERICAN COASTLINES AND NW SOUTH AMERICA LATE WED THROUGH THE END OF THE WEEK. GAP WINDS... A COLD FRONT HAS PUSHED E OF THE NORTHERN END OF THE CHIVELA PASS IN THE GULF OF MEXICO ALLOWING FOR A BRIEF 20 KT NORTHERLY SURGE IN THE NORTHERN GULF OF TEHUANTEPEC. EXPECT WINDS TO QUICKLY DIMINISH TO LESS THAN 20 KT BY THIS AFTERNOON. $$ LEWITSKY