AXPZ20 KNHC 172109
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1948 UTC Thu Aug 17 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
Based on 1800 UTC surface analysis and satellite imagery through
A surface low is analyzed near 13.5N112.5W, with estimated mean
sea level pressure of 1008 mb. Strong winds, with seas in the 7
to 9 ft range are noted within 120 NM east semicircle of the low.
Scattered moderate isolated strong convection is currently
observed within 180 nm southwest semicircle of the low.
Environmental conditions are favorable for tropical cyclone
formation as this low moves northwestward the next couple of
days. Refer to High Seas Forecast under WMO/AWIPS headers FZPN03
KNHC/MIAHSFEP2 for additional information.
..TROPICAL WAVES AND TROPICAL LOWS...
The axis of a tropical wave is near 92W north of 06N, moving west
at about 20 kt. Isolated strong convection was noted from 06N to
11N between 91W and 96W.
The axis of a tropical wave is near 107W from 07N to 21N, moving
west at 15 kt. Scattered moderate isolated strong convection is
noted from 16N to 20N between 105W and 111W.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 09N84W to 07.5N95W to 13N106W
through low pres near 13.5N112.5W to 12N120W to 13N128W to
12N140W. Scattered moderate isolated strong convection was noted
within 60 NM north of the monsoon trough east of 90W. Scattered
moderate isolated strong convection was noted within 60 NM south
of the monsoon trough between 115W and 119W. Scattered moderate
isolated strong convection was noted 90 NM north of the monsoon
trough between 122W and 127W. Scattered moderate isolated strong
convection was noted within 90 NM south of the monsoon trough
between 136W and 139W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
A ridge will dominate the forecast waters west of Baja California
producing mainly gentle to moderate northerly winds and seas in
the 4-6 ft range the remainder of the week into the upcoming
weekend. A surface trough will meander across the Baja California
Peninsula and Gulf of California through Sat night, with a
surface low developing intermittently over the northern Gulf of
Gulf of California...gentle southerly flow will persist across
the Gulf of California through the upcoming weekend.
Gulf of Tehuantepec: winds will pulse to fresh to strong during
the overnight and early morning hours through Monday, with seas
are building to 6-8 ft with these winds. On Monday, winds are
forecast to reach near gale force, with seas building to 9-10 ft.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Gulf of Papagayo: fresh to strong offshore winds are expected
during the overnight and early morning hours through Friday
morning, with moderate to fresh winds thereafter.
Otherwise, gentle NE to E winds are expected N of the monsoon
trough, while moderate southerly winds are expected S of the
monsoon trough axis through the upcoming weekend with 3 to 6 ft
REMAINDER OF THE AREA...
High pressure of 1028 mb extends a ridge southeast to near
23N116W. Except as previously mentioned in the special features
section, moderate to locally fresh anticyclonic flow is forecast
N of the monsoon trough and W of 120W.
Long period southerly swell, with seas in the 6 to 8 ft range,
is observed S of 06N between 110W and 120W. These seas will
subside to less than 8 ft tonight.