000 AXPZ20 KNHC 181616 CCA TWDEP TROPICAL WEATHER DISCUSSION...CORRECTED NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI MAR 18 2011 CORRECTED DISCUSSION SECTION TO INCLUDE CONVECTION WITH SURFACE TROUGH TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE IS CENTERED ALONG 4N98W 4N111W 7N121W 3N134W 3N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N OF THE AXIS BETWEEN 131W-139W. ...DISCUSSION... A BROAD UPPER TROUGH ENTERS THE FORECAST AREA NEAR 32N128W AND EXTENDS TO 22N130W TO 16N138W. A JET STREAM BRANCH ROUNDS THE BASE OF THE TROUGH WITH CORE WINDS OF 60-85 KT FOUND IN RIGHT ENTRANCE REGION. THESE WINDS ARE EJECTING UPPER LEVEL MOISTURE IN THE FORM OF SCATTERED TO BROKEN CIRRUS CLOUDS NORTHEASTWARD TO WELL INLAND THE INTERMOUNTAIN REGION OF THE U.S. TO THE SE OF THE TROUGH MODERATE TO STRONG SUBSIDENCE AS NOTED IN WATER VAPOR IMAGERY COVERS THE AREA FROM 12N TO 16N W OF 130W...AND ELSEWHERE SE OF THE TROUGH TO A LINE FROM 22.5N106W TO 12N130W. THIS IS MAINTAINING RATHER DRY AND STABLE CONDITIONS AT THE SURFACE WHERE BROKEN STRATOCUMULUS CLOUDS MOVING SW TO W ARE SEEN. A WEAK UPPER RIDGE AXIS EXTENDS FROM AN ANTICYCLONE LOCATED NEAR 12N102W TO 12N120W TO 10N140. ACTIVE ITCZ CONVECTION DESCRIBED ABOVE CONTINUES UNDER THE RIDGE AXIS KEEPING RIDGE IN A RATHER PERMANENT STAGE. IN ADDITION...A SURFACE TROUGH MOVING W CLOSE TO 15 KT EXTENDS FROM 13N121W TO 5N126W. THIS TROUGH HAS A VERY GOOD TRACK HISTORY ON SATELLITE IMAGERY AS NOTED OVER THE PAST FEW DAYS. THE ASSOCIATED CLOUD PATTERN IS OBSERVED TO EXHIBIT AN INVERTED-V SHAPE TYPICAL OF ATLANTIC OCEAN TROPICAL WAVES. AN AREA OF LOW-LEVEL CONVERGENCE LEFT IN ITS WAKE TO THE N OF THE ITCZ IS RESULTING SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 10N-14N BETWEEN 111W-123W. THE BROAD UPPER TROUGH DOMINATING THE NORTHERN PORTION OF THE FORECAST AREA WILL BE RELOADED WITH NORTHERN STREAM ENERGY OVER THE NEXT FEW DAYS AS A VIGOROUS UPPER LOW WITHIN THE BROAD TROUGH...AND CURRENTLY WELL N OF THE AREA ENERGIZES THE TROUGH. AS A RESULT...THIS WILL ALLOW FOR THE ASSOCIATED SURFACE COLS FRONT TO QUICKLY SWEEP SE AS DEPICTED BY THE GLOBAL MODELS AND MOVE INTO THE THE NW PORTION LATE SAT NIGHT ALONG A POSITION FROM 30N134W TO 29N140W WITH INCREASING SW-W WINDS AHEAD OF IT. THESE WINDS SHOULD BE IN THE RANGE OF 20-30 KT N OF 29N WITHIN 240 NM E OF FRONT...THEN INCREASE TO MINIMAL GALE FORCE STRENGTH BY EARLY SUN MORNING AS THE FRONT REACHES FROM 30N130W TO 27N140W WITH SEAS BUILDING...POSSIBLY UP TO 14 FT. WINDS BEHIND THE FRONT ARE FORECAST TO BE W-NW AT 20 TO 25 KT WITH SEAS TO 16 FT DUE TO A LARGE SET OF EXPECTED LONG PERIOD NW SWELLS. A 1031 MB HIGH CENTER ANALYZED WELL NW OF THE REGION NEAR 32N150W EXTENDS A RIDGE SE INTO THE FORECAST DISCUSSION AREA NEAR 29N140W ...AND TO 27N130W TO NEAR 21N110W. HIGH PRES GENERALLY COVERS THE AREA N OF 15N AND W OF 110W. FRESH TO STRONG TRADE WINDS LIE S OF THE RIDGE AXIS FROM 05N TO 25N W OF 120W. IN RESPONSE TO THE APPROACHING COLD FRONT...THE RIDGE WILL SHIFT SOUTHWARD SAT AND WEAKEN CONSIDERABLY BY SUN. THIS ACTION WILL ALLOW FOR THE AREA OF TRADES TO SHIFT S AND DIMINISH A LITTLE THROUGH EARLY SUN...AT WHICH TIME THEY ARE FORECAST TO BE CONFINED FROM 6N-16N AND W OF 131W WITH SEAS TO 9 FT. BEFORE THE RIDGE BEGINS TO SHIFT SOUTHWARD...IT WILL EXPAND SOME TO THE E OVER THE NORTHERN WATERS TODAY INTO TONIGHT. THIS WILL TIGHTEN UP THE PRES GRADIENT IN THE FAR NE PORTION ALLOWING FOR NW WINDS OF 20 KT TO DEVELOP N OF ABOUT 28N AND E OF 118W TO THE BAJA CALIFORNIA COAST...BUT THEN DIMINISH TO LESS THAN 20 KT IN 48 HOURS AS THE HIGH WEAKENS WHILE SHIFTING SOUTHWARD. A WEAK SURFACE TROUGH IS ALONG THE COAST OF COLOMBIA WITH WIDELY SCATTERED SHOWERS AND TSTMS FROM 3N-6N BETWEEN 77W-79W. THIS TROUGH IS EXPECTED TO MOVE LITTLE OVER THE NEXT 48 HOURS. GAP WINDS... GULF OF TEHUANTEPEC...AN ASCAT PASS FROM 0400 UTC LAST NIGHT CAPTURED THE PRESENTLY ON GOING EVENT OF NLY WINDS OF 20-25 KT THROUGH THE ISTHMUS OF TEHUANTEPEC WITHIN 30 NM EITHER SIDE OF LINE FROM 16N95W TO 13N96W. THESE WINDS WILL BRIEFLY PEAK TO 30 KT SAT MORNING...THEN PERHAPS WEAKEN SLIGHTLY AND PEAK AGAIN TO 30 KT EARLY SUN WHEN MORNING DRAINAGE FLOW THROUGH THE PASS IS AT ITS DIURNAL MAXIMUM. GULF OF PAPAGAYO...THE PRES GRADIENT WILL ALSO REMAIN STRONG THROUGH THE GULF OF PAPAGAYO...AND OVER THE AREA FROM 8N-11W AND W TO 92W WHERE LITTLE CHANGE IS EXPECTED IN THE STRONG NE TO E WINDS CURRENTLY FOUND IN THE GULF THROUGH THE REST OF THE PERIOD. GULF OF PANAMA...THE PRES GRADIENT CONTINUES TO STRENGTHEN BETWEEN THE COLOMBIAN LOW AND HIGH PRES OVER CENTRAL AMERICA WITH N-NE WINDS OF 20-25 KT THROUGH THE GULF AND AS FAR S AS 5N BETWEEN 78W-81W AS SEEN IN AN ASCAT PASS FROM LAST NIGHT. THESE WINDS ARE EXPECTED TO PUNCH S TO NEAR 3N AND BETWEEN 78W-81W IN 24 HOURS...THEN DIMINISH BOTH IN AREAL COVERAGE AND INTENSITY BY 48 HOURS AS THE PRES GRADIENT WEAKENS SOME. $$ AGUIRRE