000 AXPZ20 KNHC 170922 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU SEP 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0900 UTC. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS ALONG 108W FROM 12N TO 21N. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED NEAR THE SOUTHERN END OF THE WAVE AXIS FROM 12N TO 16N BETWEEN 105W AND 110W. THE WAVE IS LIKELY ENHANCING SCATTERED SHOWERS AND TSTMS ALONG THE COASTAL STATES OF MEXICO FROM JALISCO TO SOUTHERN SINALOA...INCLUDING LAS MARIAS ISLANDS. THE WAVE IS EVIDENT IN THE LATEST GFS 700 MB STREAMLINES AND 850 VORTICITY ANALYSIS AND COINCIDES WITH AN AREA OF DEEP TROPICAL MOISTURE AS NOTED ON TOTAL PRECIPITABLE WATER SATELLITE IMAGERY. A HIGH RESOLUTION ASCAT PASS SHOWED SE WINDS OF 20-25 KT BEHIND THE WAVE AXIS AND OVER THE FORECAST WATERS FROM 16N TO 19N BETWEEN 101W AND 105W. THESE WINDS ARE EXPECTED TO PERSIST DURING THE NEXT 6-12 HOURS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 09N85W TO 11N95W TO 16N108W TO 1010 MB LOW PRES NEAR 16N116W TO 10N124W TO 11N140W. NO ITCZ IS PRESENTLY IDENTIFIED. SCATTERED MODERATE ISOLATED STRONG CONVECTION CAN BE FOUND FROM 05N TO 08N BETWEEN 95W AND 98W AND FROM 09N TO 13N BETWEEN 119W AND 122W. ...DISCUSSION... A 1010 MB LOW PRES IS NEAR 16N116W WITH A TROUGH EXTENDING FROM THE LOW CENTER TO 21N116W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS SEEN MAINLY ON THE EAST SIDE OF THE TROUGH FROM 17N TO 20N BETWEEN 113W AND 116W. ISOLATED MODERATE CONVECTION IS NEAR THE LOW CENTER. THIS SYSTEM REMAINS EMBEDDED IN AN AREA OF DEEP TROPICAL MOISTURE AS NOTED IN TOTAL PRECIPITABLE WATER SATELLITE IMAGERY. AN ELONGATED CYCLONIC CIRCULATION IS BEGINNING TO DEVELOP AT THE LOW LEVELS AND SURFACE...AND IS COMBINING WITH THE TROPICAL WAVE TO THE E TO DRAW 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 MEANDER NEAR THE REVILLAGIDO ISLANDS DURING THE NEXT FEW DAYS AND EVOLVE INTO AN ELONGATED NE- SW ORIENTATED LOW LEVEL CIRCULATION. THIS SCENARIO IS EXPECTED TO CONTINUE TO TRANSPORT ABUNDANT TROPICAL MOISTURE INTO THE W COASTAL STATES OF MEXICO...WITH INCREASING MOISTURE SPREADING N ACROSS THE BAJA CALIFORNIA PENINSULA AND THE GULF OF CALIFORNIA OR SEA OF CORTEZ INTO THIS COMING WEEKEND. A 1011 MB SURFACE LOW IS ANALYZED NEAR 15N132W WITH A TROUGH EXTENDING N THEN NE FROM THE LOW CENTER TO NEAR 20N128W. THE LOW HAS BEEN MOVING SW NEAR 10 KT. NIGHT CHANNEL VISIBLE IMAGES SHOW A WELL DEFINED SWIRL OF LOW CLOUDS ASSOCIATED WITH THIS LOW WHILE ISOLATED MODERATE CONVECTION IS NEAR THE NORTHERN END OF THE TROUGH AXIS. PRES GRADIENT BETWEEN THE TROUGH AND A BUILDING RIDGE ACROSS THE N WATERS IS PRODUCING A BELT OF NE WINDS IN THE 20-25 KT RANGE WITHIN AROUND 90 NM NW OF THE TROUGH AXIS. SCATTEROMETER DATA CONFIRMED THE PRESENCE OF THESE WINDS. IN ADDITION...A PAIR OF ALTIMETER PASSES ALSO INDICATE SEAS TO AROUND 8 FT IN ASSOCIATION WITH THESE WINDS. THIS LOW PRES IS FORECAST TO WEAKEN TO AN OPEN TROUGH AND SHIFT WWD DURING THE NEXT FEW DAYS...AND MOVE OUT OF THE AREA ON FRIDAY. A 1026 MB SURFACE HIGH PRESSURE LOCATED WELL NW OF AREA NEAR 35N156W EXTENDS A RIDGE EASTWARD ACROSS THE N WATERS REACHING THE NORTHERN BAJA CALIFORNIA PENINSULA. THE HIGH IS FORECAST TO MOVE E TO A POSITION NEAR 35N150W IN ABOUT 24 HOURS. THIS WILL BRING AN INCREASE IN THE TRADE WIND FLOW ACROSS THE WEST-CENTRAL WATERS. BY TONIGHT INTO EARLY FRI...EXPECT NE WINDS OF 20-25 KT AND SEAS UP TO 8 FT FROM 20N TO 23N BETWEEN 130W AND 136W. SEAS WILL FURTHER BUILD UP TO 9 FT LATE ON FRI FROM 19N TO 24N W OF 135W. GULF OF CALIFORNIA...A N TO S ORIENTATED TROUGH CONTINUES OVER THE N HALF OF THE GULF OF CALIFORNIA AND BAJA PENINSULA. 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. WINDS WILL INCREASE TO 20 KT N OF 28N THIS EVENING BEFORE THE GRADIENT RELAXES ON FRI. $$ GR