000 AXPZ20 KNHC 201455 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1415 UTC. ...SPECIAL FEATURES... TROPICAL STORM KARINA IS CENTERED NEAR 15.8N 136.6W AT 20/1500 UTC AND IS NEAR STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WINDS 50 KT WITH GUSTS TO 65 KT. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 150 NM OF CENTER OVER ALL BUT THE NW QUADRANT. KARINA IS EXPECTED TO REMAIN NEARLY STATIONARY TODAY WITH SOME FLUCTUATIONS IN INTENSITY. KARINA IS EXPECTED TO BEGIN DRIFTING EASTWARD THU. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. TROPICAL STORM LOWELL IS CENTERED NEAR 19.1N 121.2W AT 20/1500 UTC MOVING NW OR 310 DEG AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB. MAXIMUM SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM OF THE CENTER OVER THE S SEMICIRCLE. SCATTERED MODERATE CONVECTION COVERS THE AREA ELSEWHERE FROM 15N-22N BETWEEN 118W- 124W. LOWELL REMAINS A VERY LARGE CIRCULATION WITH TROPICAL STORM WINDS EXTENDING OUT FROM THE CENTER TO 170 NM. ALTIMETER PASSES AROUND 0400 UTC PROVIDED EXCELLENT SEA HEIGHT DATA FOR THE TROPICAL CYCLONE...INCLUDING HIGH CONFIDENCE IN THE RADIUS OF 12 FT SEAS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. TROPICAL WAVE EXTENDS FROM THE COAST OF OF MEXICO IN THE GULF OF TEHUANTEPEC NEAR 16N95W TO 1008 MB LOW NEAR 08N94W MOVING W 10 TO 15 KT OVER PAST 24 HOURS. SCATTERED MODERATE TO STRONG CONVECTION COVERS A BROAD AREA N OF 9N TO THE COAST OF CENTRAL AMERICA/MEXICO BETWEEN 88W-102W. MODEL GUIDANCE INDICATES PERIPHERAL WINDS WILL INCREASE DOWNSTREAM FROM GULF OF PAPAGAYO TONIGHT WHICH WILL ALLOW THE LOW TO BECOME BETTER ORGANIZED AS IT CONTINUES WESTWARD. THIS LOW HAS A MEDIUM CHANCE FOR TROPICAL CYCLONE DEVELOPMENT DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... SEE SPECIAL FEATURES ABOVE. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A MONSOON TROUGH EXTENDS FROM 8N78W TO 1008 MB LOW NEAR 8N94W ALONG 8N104W TO 9N111W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE MONSOON TROUGH BETWEEN 77W- 82W AND WITHIN 180 NM S OF THE MONSOON TROUGH BETWEEN 94W-107W. ...DISCUSSION... A 1026 MB HIGH IS WELL NW OF THE DISCUSSION AREA WITH A SURFACE RIDGE EXTENDING SE THROUGH 32N133W TO BAJA CALIFORNIA NEAR 30N116W. THE RIDGE CONTINUES TO MAINTAIN MODERATE WINDS ACROSS THE FORECAST WATERS W OF 110W OUTSIDE OF THE CIRCULATION INFLUENCE OF KARINA AND LOWELL. THIS RIDGE WILL SHIFT N AS LOWELL MOVES POLEWARD OVER THE NEXT 2-3 DAYS . THIS WILL TIGHTENING THE PRESSURE GRADIENT OVER THE NW PORTION OF THE DISCUSSION AREA INCREASING WINDS TO STRONG BY FRI MORNING. STRONG GAP WINDS ARE IN GULF OF PAPAGAYO THIS MORNING AND WILL SHIFT W TODAY BUILDING SEAS TO 8 FT THIS EVENING. THESE WINDS AND SEAS WILL CONTRIBUTE TO THE DEVELOPING SYSTEM IN THE SPECIAL FEATURES ABOVE. AN UPPER RIDGE OVER MEXICO EXTENDS INTO THE REGION THROUGH 23N126W TO E OF T.S. LOWELL NEAR 17N110W. THIS IS ENHANCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 11N-17N BETWEEN 104W-112W AND FROM 19N-25N E OF 110W TO COAST OF MEXICO INCLUDING S GULF OF CALIFORNIA. $$ PAW