000 AXPZ20 KNHC 202151 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED AUG 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...SPECIAL FEATURES... TROPICAL STORM KARINA IS CENTERED NEAR 15.7N 136.7W AT 20/2100 UTC AND IS NEARLY STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 994 MB. MAXIMUM SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER...AND ALSO WITHIN 150 NM SE OF A LINE FROM 15N137W TO 12N140W. LITTLE MOTION IS EXPECTED TODAY 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 19.4N 121.5W AT 20/2100 UTC MOVING NW OR 315 DEG AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 988 MB. MAXIMUM SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS WITHIN 150 NM IN THE N AND 240 NM IN THE S SEMICIRCLES. LOWELL REMAINS A VERY LARGE CIRCULATION WITH TROPICAL STORM WINDS EXTENDING OUT AS MUCH AS 180 NM FROM THE CENTER. LOWELL WILL CONTINUE TO MOVE TO THE NW TONIGHT...FOLLOWED BY AN INCREASE IN FORWARD SPEED ON THU THROUGH FRI. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. A TROPICAL WAVE EXTENDS FROM 1008 MB LOW PRES NEAR 09.5N94W 1008 MB TO 16N95W MOVING W AT 5-10 KT. UPPER LEVEL DIFFLUENCE ACROSS THE WATERS N OF 04N BETWEEN 90W AND 102W CONTINUES TO SUPPORT CONVECTION. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 180 NM IN THE SE SEMICIRCLE...N OF 09N E OF THE TROPICAL WAVE TO CENTRAL AMERICA...AND ALSO FROM 04N TO 14N W OF THE TROPICAL WAVE TO 100W. AN EARLIER ASCAT SCATTEROMETER PASS SHOWED AN AREA OF FRESH TO STRONG E-SE WINDS NE OF THE LOW AND E OF THE WAVE 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 MEDIUM CHANCE OF TROPICAL CYCLONE FORMATION DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... SEE SPECIAL FEATURES ABOVE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 07N77W TO LOW PRES NEAR 09.5N94W TO 06N103W TO 10N114W. NO ITCZ AXIS IS PRESENT E OF 140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 150 NM S OF THE AXIS E OF 81W AND BETWEEN 82W AND 86W...WITHIN 180 NM S OF THE AXIS BETWEEN 95W AND 103W...AND FROM 04N TO 09N BETWEEN 104W AND 107W. SCATTERED MODERATE CONVECTION IS FROM 12N TO 15N BETWEEN 111W AND 114W. ...DISCUSSION... A 1027 MB HIGH IS WELL NW OF THE DISCUSSION AREA NEAR 39N143W WITH A SURFACE RIDGE EXTENDING SE THROUGH 32N137W TO BAJA CALIFORNIA NEAR 30N115W. THE RIDGE HAS BEEN SHIFTING NORTHWARD IN ADVANCE OF LOWELL TO THE SE-S. 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 LATE THU THROUGH FRI AS LOWELL MOVES MOVE INTO THE RIDGE WITH FRESH TO STRONG NE WINDS DEVELOPING AND 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 S OF THE EQUATOR. $$ LEWITSKY