000 AXPZ20 KNHC 162216 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED SEP 16 2015 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 2130 UTC. ...TROPICAL WAVES AND TROPICAL LOWS... A TROPICAL WAVE EXTENDS FROM THE SW GULF OF HONDURAS AND ADJACENT LAND AREAS N-NE TO E CENTRAL GULF OF MEXICO. ASSOCIATED MOISTURE IS CONTRIBUTING TO PACIFIC CONVECTION OFFSHORE OF THE COASTS OF SAN SALVADOR AND GUATEMALA. A TROPICAL WAVE IS INVOF 105W-107W AND HAS BEEN MOVING W 10-15 KT. A LARGE AREA OF AREA OF CONVECTION CONTINUES TO ACCOMPANY THIS WAVE...WITH SCATTERED MODERATE TO STRONG FROM 11N TO 17.5N BETWEEN 101W AND 110W. ASSOCIATED ABUNDANT MOISTURE EXTENDS NE TO THE COASTAL STATES OF MEXICO. A TROPICAL WAVE IS INVOF 113W-115W WITH LOW PRES 1010 MB NEAR 16.5N115W. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED IN MAINLY TWO LARGE CLUSTERS FROM 13.5N TO 18.5N BETWEEN 110.5W AND 117W. A BROAD AND ELONGATED CYCLONIC CIRCULATION IS BEGINNING TO DEVELOP AT THE LOW LEVELS AND SURFACE...AND IS DRAWING TROPICAL MOISTURE FROM THE TROPICS INTO THE ENTRANCE AND S HALF OF THE GULF OF CALIFORNIA AND ADJACENT LAND AREAS. GLOBAL MODELS SUGGEST THAT THIS SYSTEM WILL MOVE SLOWLY W DURING THE NEXT FEW DAYS AND EVOLVE INTO AN ELONGATED LOW LEVEL NE-SW ORIENTATED CIRCULATION. A 1011 MB SURFACE LOW IS ANALYZED NEAR 16N131W WITH A TROUGH EXTENDING N THEN NE TO 21.5N126.5W. THE LOW HAS BEEN MOVING W-SW NEAR 10 KT TODAY. A NARROW ZONE OF SCATTERED TO NUMEROUS WEAK CONVECTION IS OCCURRING WITHIN 90 NM NW OF TROUGH AND LOW...WITH A FEW MODERATE EMBEDDED TSTMS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 10N75W TO 08N80W TO 09.5N93W TO 14.5N103W TO LOW PRES 1010 MB NEAR 16.5N115W TO 10N126W TO BEYOND 11N140W. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED FROM 03.5N TO BEYOND 10N E OF 86W. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED WITHIN 240 NM N AND 270 NM S OF TROUGH BETWEEN 91W AND 101W. ISOLATED TO SCATTERED MODERATE TO STRONG CONVECTION IS NOTED WITHIN 330 NM S OF TROUGH BETWEEN 117W AND 134W. ...DISCUSSION... SURFACE HIGH PRESSURE RIDGE EXTENDS FROM A 1027 MB HIGH NEAR 37N157W SE ACROSS N CENTRAL AND NE PORTIONS OF THE AREA TO NEAR 24N115W. THE GRADIENT S OF THE RIDGE IS SUPPORTING NE 20 KT TRADES ACROSS THE TROPICS FROM 14-20N W OF THE LOW AND TROUGH ALONG 131W. AFTERNOON SCATTEROMETER DATA INDICATES A SOLID AREA OF 20 KT NE WINDS WITHIN 90 NM W AND NW OF THE TROUGH...WHERE COMBINED SEAS ARE 7-8 FT. THE LOW OR ITS REMNANTS WILL SHIFT W OVER THE NEXT FEW DAYS WHILE THE TROUGH MOVES MORE WNW...AND WILL MAINTAIN A MODEST GRADIENT WITH 20 KT WINDS NW OF THE TROUGH...INCREASING TO 20-25 KT THU. GULF OF CALIFORNIA...A N TO S ORIENTATED TROUGH CONTINUES OVER THE N HALF OF THE GULF OF CALIFORNIA AND BAJA PENINSULA THIS AFTERNOON. THE PRESSURE GRADIENT BETWEEN THE RIDGE AND THIS TROUGH CONTINUES TO SUPPORT NORTHERLY WINDS NEAR 15 KT ALONG THE W COASTAL WATERS OF THE PENINSULA...EXCEPT FOR 15-20 KT SURROUNDING PUNTA EUGENIA. THE HIGH ACROSS THE CENTRAL PACIFIC WILL SHIFT VERY SLIGHTLY EASTWARD DURING THE NEXT 24 HOURS AND PRODUCE A MODEST INCREASE IN THESE WINDS TONIGHT THROUGH THU...WITH WINDS INCREASING TO 20 KT N OF 28N THU EVENING BEFORE THE GRADIENT RELAXES FRI. $$ STRIPLING