000 AXPZ20 KNHC 270249 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 248 UTC Thu Apr 27 2017 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 0230 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough axis extends from 07N80W TO 07N89W to 05N95W to 07N101W where scatterometer winds from this evening indicate that the northern ITCZ forms and continues to 06N112W to 05N122W to 05N131W to 03N140W. A southern hemispheric ITCZ axis extends from 03.4S107W to 03.4S120W. Scattered moderate to strong convection is noted within 120 nm south of the axis between 112W and 115W. Scattered strong convection is within 60 nm north of the axis between 107W and 110W, and and within 60 nm of the axis between 117W and 119W. Scattered moderate isolated strong convection is within 120 nm south of the axis between 85W and 90W, within 180 nm north of the axis between 126W and 131W, within 60 nm south of the axis between 90W and 97W and within 60 nm of the axis between 138W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A tight pressure gradient over the northeast portion of the area between high pressure ridging that extends southeastward over the area and the thermal trough across the Gulf of California is bringing strong to near gale force northwest winds just north of the discussion waters east of 125W. Seas generated by these winds are in the range of 9 to 12 ft. The northwest swell associated with these seas has propagated into the northeast part of the discussion waters just to the west of the Baja California Peninsula to near 122W, where 10 to 11 ft combined seas are observed. Peak seas to 10 ft have reached southward to near 20N and west to near 125W. The tight pressure gradient will weaken some early this evening, but tighten again late tonight into Thursday morning, with northwest winds increasing to the strong category north of about 28N between 117W and 124W, with generated combined seas of 9 to 12 ft. These winds will continue through Friday allowing for combined seas to build some more to around 13 ft north of 29N between 119W and 121W. Seas to 10 ft will continue to press southward elsewhere north of 20N between 115W and 129W. The gradient should begin to relax late on Friday night, with the area of strong northwest to north winds gradually shifting westward as high pressure just north of the area moves to the northeast. Gulf of California: Light and variable winds are occurring throughout the Gulf, except in the southern sector where the flow is mainly gentle from the south and southwest in direction. The flow will become generally moderate to locally fresh from the southwest and west during Friday across just about the entire Gulf as the thermal trough becomes more pronounced. Gulf of Tehuantepec: Gentle to moderate south to southwest flow will continue through Friday as suggested in the latest scatterometer data. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Mostly a gentle onshore breeze is expected during the day becoming offshore along the coasts at night. Combined seas of 4 to 5 ft in mixed SW and NW swell are forecast during the next several days. REMAINDER OF THE AREA... A 1029 mb high pressure system is analyzed at 32N139W, with a ridge extending southeastward to near 18N117W. The 1029 mb high center will weaken slightly as it moves north-northeast through Thursday allowing the present tight gradient over the northeast portion to slacken some this evening, but then tighten again late tonight through Thursday. This will support strong northwest to north winds and seas of 8 to 11 ft over the northeast portion outside the waters within 250 nm of Mexico. These conditions will change little through Friday. Fresh northeast trades are expected to the south of the ridge axis to zone of the ITCZ, and will maintain seas of 6 to 8 ft to the west of 121W through Thursday, and from 07N to 21N west of 136W on Friday. Southern hemispheric cross-equatorial swell will produce seas in the range of 7 to 9 ft to reach the equator between 106W and 120W on Fri. $$ Aguirre