000 AXPZ20 KNHC 210248 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU AUG 21 2014 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0215 UTC. ...SPECIAL FEATURES... TROPICAL STORM KARINA IS CENTERED NEAR 15.9N 136.4W AT 21/0300 UTC AND IS NEARLY STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT. NUMEROUS MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 60 NM IN THE E AND 120 NM IN THE W SEMICIRCLES. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM SE OF A LINE FROM 14N137W TO 11N140W. LITTLE MOTION IS EXPECTED OVERNIGHT AND AN EASTWARD DRIFT SHOULD BEGIN ON THU. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 48 HOURS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. TROPICAL STORM LOWELL IS CENTERED NEAR 19.6N 121.6W AT 21/0300 UTC MOVING NW OR 320 DEG AT 3 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 988 MB. MAXIMUM SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT. NUMEROUS MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 180 NM IN THE N SEMICIRCLE...240 NM IN THE SE AND 300 NM IN THE SW QUADRANTS. LOWELL REMAINS A VERY LARGE CIRCULATION WITH TROPICAL STORM FORCE WINDS EXTENDING UP TO 180 NM FROM THE CENTER. LOWELL WILL CONTINUE TO MOVE TO THE NW TONIGHT FOLLOWED BY A GRADUAL INCREASE IN FORWARD SPEED ON THU THROUGH FRI. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. LOW PRES IS NEAR 09.5N94.5W AT 1007 MB MOVING W AT AROUND 5-10 KT WITH A TROUGH AXIS...FORMERLY A TROPICAL WAVE...EXTENDING NORTHWARD TO THE GULF OF TEHUANTEPEC. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER. AN EARLIER ASCAT SCATTEROMETER PASS SHOWED AN AREA OF FRESH TO STRONG E-SE WINDS NE OF THE LOW AND E OF THE TROUGH AXIS. THIS ENERGY WILL FEED INTO THE CIRCULATION OF THE LOW WITH FRESH TO STRONG WINDS AND ASSOCIATED SEAS EXPANDING IN COVERAGE AROUND THE LOW THROUGH THE NEXT 48 HOURS AS IT CONTINUES TO MOVE IN A WESTWARD DIRECTION. THE LOW HAS A HIGH CHANCE OF TROPICAL CYCLONE FORMATION DURING THE NEXT 48 HOURS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 08N78W TO LOW PRES NEAR 09.5N94.5W TO 06N103W TO 10N115W. NO ITCZ AXIS IS PRESENT E OF 140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 05N TO 09N BETWEEN 82W AND 86W...WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 86W AND 93W...WITHIN 180 NM SE OF THE AXIS BETWEEN 96W AND 99W...AND WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 99W AND 107W. ...DISCUSSION... A 1027 MB HIGH IS WELL NW OF THE DISCUSSION AREA NEAR 40N143W WITH A SURFACE RIDGE EXTENDING SE THROUGH 32N128W TO NEAR THE MEXICO/CALIFORNIA BORDER NEAR 32N117W. THE RIDGE HAS BEEN SHIFTING NORTHWARD IN ADVANCE OF LOWELL. THE RIDGE CONTINUES TO MAINTAIN MODERATE WINDS ACROSS THE FORECAST WATERS W OF 110W OUTSIDE OF THE INFLUENCES OF KARINA AND LOWELL. THE PRES GRADIENT WILL TIGHTEN OVER THE NW CORNER OF THE AREA THU NIGHT THROUGH FRI AS LOWELL MOVES INTO THE RIDGE WITH FRESH TO STRONG NE WINDS DEVELOPING WITH BUILDING SEAS TO 8-9 FT IN THE NW PORTION. AN AREA OF MIXED SE AND SW SWELL WILL APPROACH THE EQUATOR SW OF THE GALAPAGOS ISLANDS...ALTHOUGH SEAS OF 8 FT OR GREATER SHOULD REMAIN SUPPRESSED JUST S OF THE EQUATOR. $$ LEWITSKY