000 AXPZ20 KNHC 280232 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Aug 28 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. ..TROPICAL WAVES AND TROPICAL LOWS... A tropical low pressure is analyzed at 07.5N86.5W and is estimated at 1009 mb. Although is a well-defined cyclonic circulation, convection has decreased significantly over the past 5 hours. A tropical wave is analyzed to the N of 06N along 102W and has moved W at 10 kt over the past 24 hours. Scattered moderate isolated strong convection is observed to the S of 15N within 150 nm E and within 420 nm W of the wave axis. A tropical wave is analyzed from 10N115W TO 21N114W, with scattered moderate isolated strong convection noted to the S of 19N within 150 nm E, and within 240 nm W of the wave axis. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W across the far SW Caribbean along 09.5N and continues W to the Pacific Coast of Costa Rica at 09N84W, then turns SW through an embedded 1009 mb surface low at 07.5N86.5W, then the monsoon trough turns abruptly NW through a tropical wave at 13N102W to 15N111W, then turns SW through another tropical wave at 14N115W, then wiggles WSW to beyond 10.5N140W. Scattered moderate isolated strong convection is observed S of the monsoon trough across the waters N of 05N E of 84W, within 150 nm of 08N92W, and elsewhere within 120 nm either side of a line from 12N123W to 09.5N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW to SE orientated ridge extends across EPAC waters well beyond 250 nm. The resultant pressure gradient will support a moderate NW breeze across the open waters W of the Baja California Peninsula this week, except increasing to a fresh NW breeze within about 90 nm of the Pacific Coast of Baja California on Mon evening in the wake of a weak cold front. The weak cold front is forecast to stall and wash out along 28N late Mon night through midday on Tue. Expect a brief moderate SW-W-NW wind shift near the front across the Gulf of California, otherwise light and variable flow is expected across the Gulf waters through Wed morning. The leading edge of a swath of fresh to locally strong southwesterly monsoon flow and 7 to 11 ft seas, has reached along 14N across the waters 250 nm seaward between 98W and 120W. A tropical low is forecast to develop near 16N108W on Mon, and track N between 107W and 112W early in the week, with favorable environmental conditions for tropical cyclone formation. A band of fresh to locally strong southerly flow with building seas and banding TSTMS is forecast to develop within about 300 nm E of the low, and these conditions will shift N and W across the Mexican offshore waters between about 103W and 115W this week, with winds increasing to at least near gale force. The current forecast is for strong SE flow, and 6 to 8 ft seas, and significant convection, to spread N across the southern Gulf of California beginning late Wed night, with near gale conditions across the southern Gulf waters on Fri morning as the low center then tracks NW across the offshore waters W of Baja. Plenty of uncertainty in this scenario, and changes to track and intensity are very likely. Gulf of Tehuantepec: light offshore nocturnal flow expected this week, with light to gentle onshore flow during the day. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate ENE flow forecast through midday Mon. Otherwise, light and variable flow is expected N of the monsoon trough through the middle of next week, while moderate to locally fresh southerly winds are expected S of the monsoon trough axis. Long period southerly cross-equatorial swell, in the form of 7 to 9 ft seas is currently along 03N, and will continue to propagate N reaching along 06N by early Mon, then subside Mon night with seas forecast to less than 8 ft on Tue. REMAINDER OF THE AREA... The remnant low of former tropical cyclone Kenneth continues to spin near 29N136W. The estimated minimum central pressure is 1017 mb. This low should finally weaken to an open trough late tonight. A ridge extends from 32N129W to near 19N111W, and is accompanied by moderate anticyclonic winds and 4 to 6 ft seas. Fresh to locally strong southerly monsoonal winds and seas of 7 to 10 ft are observed from 04N to 14N between 100W and 130W. These conditions will continue this week as a surface low previously described develops near 16N108W. $$ Nelson