000 AXPZ20 KNHC 191810 AAA TWDEP TROPICAL WEATHER DISCUSSION...AMD NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED SEP 19 2007 AMENDED IN ORDER TO INCLUDE INFORMATION ABOUT TROPICAL DEPRESSION 13-E NEAR 17.1N 127.9W AT 19/1700 UTC... 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. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM IVO IS NEAR 15.3N 111.1W AT 19/1500 UTC MOVING WEST-NORTHWEST 10 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 994 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 55 KT WITH GUSTS TO 65 KT. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS WITHIN A 30 NM RADIUS OF 15.5N 111.5W. SOME OF THE CLOUD TOP TEMPERATURES HAVE BEEN WARMING DURING THE LAST 4 TO 5 HOURS FROM 13N TO 15N BETWEEN 111W AND 113W...BUT STILL EXPECT SHOWERS AND THUNDERSTORMS IN THIS AREA. THE CLOUD TOP TEMPERATURES DEFINITELY HAVE BEEN WARMING...GOING FROM AS COLD AS -80C TO -68C. SHOWERS AND THUNDERSTORMS ARE POSSIBLE STILL IN THIS AREA. OTHER ISOLATED SHOWERS COVER THE REST OF THE AREA FROM 10N TO 19N BETWEEN 104W AND 114W. CONTINUED STRENGTHENING OF IVO IS FORECAST DURING THE NEXT 72 HOURS...TO A CATEGORY ONE HURRICANE. TROPICAL DEPRESSION 13-E DEVELOPED AT 19/1700 UTC...AND THE CENTER OF TROPICAL DEPRESSION 13-E IS NEAR 17.1N 127.9W... MOVING WEST 6 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 30 KT WITH GUSTS TO 40 KT. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ123 KNHC FOR MORE DETAILS. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 14N TO 16N BETWEEN 111W AND 112.5W. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE ELSEWHERE FROM 10N TO 20N BETWEEN 105W AND 114W. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 86W SOUTH OF 21N MOVING WEST 10 TO 15 KT. STRONG SHOWERS AND THUNDERSTORMS ARE WITHIN 30 NM OF THE COAST OF COSTA RICA. THIS PRECIPITATION MAY OR MAY NOT BE RELATED TO THE WAVE. ...THE ITCZ... 11N88W 10N95W 12N100W 16N107W...12N113W 14N119W 16N124W... 15N131W 11N140W. ISOLATED MODERATE SHOWERS AND SOME THUNDERSTORMS...SOME CELLS DISSIPATE AND ALTERNATELY OTHER CELLS DEVELOP...FROM 8N TO 11N BETWEEN 90W AND 100W...AND FROM 11N TO 15N BETWEEN 91W AND 99W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 8.5N TO 11N BETWEEN 114W AND 118W... AND FROM 10N TO 13N BETWEEN 130W AND 140W. SCATTERED STRONG SHOWERS AND THUNDERSTORMS FROM 12N TO 14N BETWEEN 119W AND 122W...FROM 14N TO 15N BETWEEN 131W AND 132W...FROM 13N TO 14N BETWEEN 136W AND 137W. ...DISCUSSION... TROPICAL STORM IVO AND TROPICAL DEPRESSION 13-E ARE ANCHORING AN ACTIVE LOW PRESSURE TROUGH THAT STRETCHES FROM 105W TO 135W. WATER VAPOR IMAGERY SHOWS DIFFLUENT FLOW ALOFT WHICH IS ENHANCING TROPICAL CYCLONE DEVELOPMENT IN THE REGION. THE LARGER SCALE SURFACE PRESSURE PATTERN ACROSS THE SUBTROPICS IS DOMINATED BY HIGH PRESSURE CENTERED NW OF THE AREA. THE TIGHTENED GRADIENT BETWEEN THIS HIGH CENTER AND THE TROUGH ALONG THE ITCZ IS MAINTAINING STRONG NORTHEASTERLY TRADEWINDS WEST OF 125W. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS FROM 5N TO PANAMA EAST OF 80W IN AN AREA OF MIDDLE LEVEL DIFFLUENT FLOW. NORTH-NORTHEASTERLY WINDS FROM 20 TO 25 KT ARE FUNNELING THROUGH THE GULF OF TEHUANTEPEC WITH SEAS TO 8 FT EXTENDING ABOUT 60 NM OUT TO SEA. THESE WINDS ARE FORECAST TO CONTINUE DURING THE NEXT 36 HOURS. MIDDLE TO UPPER LEVEL CYCLONIC FLOW IS NORTH OF 35N EAST OF 131W IS ASSOCIATED WITH A TROUGH THAT IS DROPPING SOUTHWARD IN CALIFORNIA. UPPER LEVEL ANTICYCLONIC FLOW IS NORTH OF 33N WEST OF 131W. UPPER LEVEL SOUTHWESTERLY WIND FLOW IS WITHIN 200 TO 250 NM ON EITHER SIDE OF 26N140W BEYOND 33N118W IN DRY AIR/ SUBSIDENCE. AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTER IS NEAR 21N124W. THIS CENTER IS PROVIDING EASTERLY SHEAR OVER THE DEEP TROPICS SOUTH OF 15N WEST OF 115W. $$ MT