000 AXPZ20 KNHC 041531 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED MAY 04 2011 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 1500 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS CENTERED ALONG 07N77W TO 03N90W TO 06N105W TO 07N125W TO 04N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 02N TO 11N BETWEEN 106W AND 118W. CLUSTER OF MODERATE TO STRONG CONVECTION IS WITHIN 70 NM OF 06N79W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM EITHER SIDE OF AXIS BETWEEN 82W AND 85W...AND WITHIN 90 NM S OF AXIS BETWEEN 86W AND 90W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS ALSO SEEN NEAR 11N95W AND NEAR 14N102W. ...DISCUSSION... AN UPPER LEVEL TROUGH IS IVER THE N WATERS AN EXTENDS FROM A CYCLONE NEAR 30N135W TO 27N120W THEN CONTINUES SE TO NEAR 12N100W. TO ITS E BROAD MID/UPPER LEVEL RIDGING IS PRESENT TO EASTWARD OVER MEXICO...WITH THE ASSOCIATED ANTICYCLONE ANCHORED OVER SE MEXICO AND GUATEMALA NEAR 16N91W. SWLY FLOW BETWEEN THE ANTICYCLONE AND TROUGH IS FUNNELING EXTENSIVE MID/UPPER LEVEL MOISTURE TO ACROSS NORTHERN AND WESTERN MEXICO N OF 19N. BOTH THE TROUGH AND ANTICYCLONE WILL GRADUALLY SHIFT EASTWARD. A SHORT-WAVE TROUGH IS ALONG 119W/120W S OF 15N. A DIFFLUENT PATTERN ALOFT AHEAD OF THE TROUGH AXIS IS HELPING TO MAINTAIN THE AREA OF MODERATE TO ISOLATED STRONG CONVECTION NOTED FROM 02N TO 11N BETWEEN 106W AND 118W. OVERALL THE UPPER LEVELS ARE MOSTLY MOIST AS SEEN ON WATER VAPOR IMAGERY...WHILE OVER THE EASTERN PORTION OF THE AREA THE ATMOSPHERE IS RATHER DRY AND STABLE UNDER MODERATE SUBSIDENCE SEEN TO THE E OF ABOUT 95W. IN THE FAR EASTERN PORTION...THE TAIL END OF A CENTRAL CARIBBEAN SEA UPPER LEVEL TROUGH STRETCHES SW TO OVER COSTA RICA AND WESTERN PANAMA TO NEAR 4N90W. THE TROUGH IS KEEPING ITCZ-RELATED CONVECTION TO ITS E QUITE ACTIVE. THIS TROUGH IS FORECAST TO CONTINUE TO MOVE EAST DURING THE NEXT 24-36 HOURS. AT THE LOW LEVELS...FLOW IS DOMINATED BY A 1033 MB SURFACE HIGH WELL N OF THE DISCUSSION AREA NEAR 41N132W THAT EXTENDS A RIDGE THROUGH THE FORECAST WATERS TO NEAR 20N115W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES TO ITS S NEAR THE ITCZ IS ENOUGH TO INDUCE NE 20 KT TRADE WINDS N OF 07N W OF 130W. SEAS THERE ARE UP TO 9 FT. THIS AREA OF TRADES IS FORECAST TO GRADUALLY DIMINISH OVER THE NEXT 24 TO 48 HOURS AS THE HIGH MOVES SW AND WEAKENS. A WEAK TROUGH IS WITHIN THE ITCZ AND EXTENDS FROM 11N106W TO 06N114W MOVING SLOWLY W. THIS TROUGH IS AIDING ITCZ CONVECTION IN ITS VICINITY. GAP WINDS... GULF OF TEHUANTEPEC...GALE FORCE CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE GULF OF TEHUANTEPEC BEFORE DIMINISHING TO BELOW 35 KT THU MORNING. VISIBLE SATELLITE IMAGERY REVEALS AN ARC CLOUD LINE LOCATED ABOUT 300 NM SSW OF THE GULF PROPAGATING AWAY FROM IT. THIS IS A SIGN THAT A GAP WIND EVENT IS TAKING PLACE SINCE THIS FEATURE MARKS THE LEADING EDGE OF THE NLY WIND SURGE. UNFORTUNATELY...THE LATEST ASCAT PASS MISSED THE AREA. SHIP A8JS7 LOCATED NEAR 12N98W AND DOWNSTREAM OF THIS GULF REPORTED SUSTAINED WINDS OF 25 KT AND SEAS UP TO 14 FT THIS MORNING. CURRENTLY...IXTEPEC IN OAXACA MEXICO IS REPORTING SUSTAINED WINDS OF 25 KT WITH GUSTS OF 35 KT. THIS GAP WIND EVENT IS EXPECTED TO PEAK THIS AFTERNOON WITH POSSIBLE MAXIMUM WINDS REACHING 40 KT. MODEL GUIDANCE INDICATES THAT THE EVENT WILL THEN WIND DOWN TONIGHT THROUGH EARLY THU MORNING. WINDS ARE FORECAST TO BE LESS THAN GALE FORCE BY 05/1200 UTC. IF THIS EVENT VERIFIES...THIS WILL BE THE FIFTH GALE FORCE WIND EVENT DURING THE MONTH OF MAY SINCE RECORDS BEGAN IN 1999. NE SWELLS IN ASSOCIATION WITH THIS GALE EVENT WILL SPREAD S AND SW...RAISING SEAS TO A RANGE OF 8-11 FT FROM 06N TO 14N BETWEEN 92W AND 107W IN 24 HOURS...AND S OF 12N BETWEEN 05W AND 110W IN 48 HOURS. GULF OF PAPAGAYO...NE TO E WINDS OF 20 TO 25 KT WILL CONTINUE TO PULSE THROUGH FRI MORNING IN THE AREA MARKED FROM 09N TO 12N AND E OF ABOUT 90W. THESE WINDS ARE GREATEST LATE AT NIGHT AND INTO THE EARLY MORNING HOURS. $$ GR