Tropical Weather Discussion

axpz20 knhc 191607

Tropical weather discussion  
NWS National Hurricane Center Miami FL
1605 UTC Fri Oct 19 2018  

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 1200 UTC surface analysis and satellite imagery through 
1545 UTC.      

...Special features... 

Former easternmost surface low developed into Tropical 
Depression Twenty-Three-E. As of 1500 UTC, the center of twenty-
three-E was located near 13.3n 91.9w. Maximum sustained winds 
are 30 kt with gusts to 40 kt. Estimated minimum central 
pressure is 1006 mb. Twenty-three-E is moving WNW at 2 kt. A 
west-northwestward or westward motion with an increase in 
forward speed is expected during the next few days.
On the forecast track, the center of the depression is expected 
to remain south of the coasts of Guatemala and southern Mexico 
through early next week. Strengthening is forecast during the 
next few days, and the depression is forecast to become a 
tropical storm later today. Numerous moderate convection is 
within 90 nm of the depression center. 5 to 10 inches of rain 
with local amounts to 15 inches are expected today across 
portions of El Salvador and southern Guatemala, with 3 to 6 
inches and local amounts to 10 inches near the Pacific coast of 
southeastern Mexico. This rainfall could produce life-
threatening flash flooding and landslides within mountainous 
terrain. Refer to the latest National Hurricane Center public 
advisory under AWIPS/WMO header miatcpep3/wtpz33 knhc for 
additional details.

A low pressure is located about 180 nm south of Guerrero, Mexico 
near 15n102w with an estimated surface pressure of 1007 mb. 
Scattered moderate convection is within 90 nm of the low center, 
however a cluster of moderate to isolated strong convection is 
in the SW quadrant of the low from 11n to 15n between 102w and 
105w. Environmental conditions are expected to become 
increasingly favorable for further development, and a tropical 
depression is likely to form during the next day or two while 
the low moves westward or west-northwestward offshore of the 
coast of southwestern Mexico. This surface low has a high chance 
of developing into a tropical cyclone over the next 2 days. 
Refer to the latest east Pacific tropical weather outlook under 
AWIPS/WMO header miatwoep/abpz20 knhc for additional details.  

...Intertropical convergence zone/monsoon trough... 

The monsoon trough extends from 10n84w to T.D. 23-E near 
13.3n91.9w to low pressure at 15n102w to low pressure near 
11n118w to 10n140w. Aside from the convection associated with 
T.D. And the low near 102.5w, scattered moderate convection is 
from 15n to 21n between 104w and 109w, and from 06n to 10n 
between 134w and 140w. 


Offshore waters within 250 nm of Mexico... 

See the special features paragraph above for a discussion on 
several synoptic features affecting the central and southern 
Mexico offshore waters today and through early next week.  

Strong northerly gap drainage winds are expected to continue 
through and downstream of the Gulf of Tehuantepec through this 
morning feeding into the westernmost surface low. 

A surface ridge will meander across the offshore waters from 
23n117w to 17n109w for the next few days. Gentle northwest to 
north flow is expected north of 20n west of 110w through early 
Mon. The pressure gradient is then forecast to tighten 
supporting moderate northerly flow west of the Baja California 
peninsula through the middle of next week.

Gulf of california: high pressure north of the area will support 
fresh to strong northerly winds across the Gulf waters north of 
29n through this morning. Gentle to moderate northerly winds are 
forecast across the remainder Gulf waters through the upcoming 

Offshore waters within 250 nm of Central America, Colombia, and 
within 750 nm of Ecuador...

Gentle to moderate southwesterly to westerly monsoonal flow will 
dominate the offshore waters through Sat night. Fresh southwest 
winds are expected to develop south of 05n east of 90w on Sat 
night with seas to 9 ft.  These conditions will reach the coast 
of Panama early next week.  

Otherwise, showers and thunderstorms associated with the 
features in the special features paragraph above will continue 
to affect portions of Central America and adjacent Pacific 
coastal waters today. 

Remainder of the area...   

Elsewhere, a surface ridge will meander from 12n131w to 23n117w 
through the upcoming weekend. A 1008 surface low is analyzed 
near 10n118w, and is expected to drift west for a day or so 
accompanied by fresh to locally strong winds and seas to 8 ft. 
An area of strong northeast trades is observed from 12n to 15n 
west of 132w, surrounded by seas to 10 ft in mixed swell across 
the discussion waters north of 11n west of 128w. These seas will 
gradually subside through the middle of next week. 

Long period southerly swell, in form of 8 ft seas, will enter 
the southern waters on Sat and propagate northeast to along 10n 
east of 120w through sun.   



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