ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
Issued by the NWS Weather Prediction Center College Park MD
650 AM PDT Wed Sep 19 2018

Updated first system to raise probabilities

For the eastern North Pacific...east of 140 degrees west longitude:

1. Updated: Satellite imagery and surface observations indicate that a
low pressure area over the southern Gulf of California has become
better defined this morning.  This system could become a tropical
depression later today before moving into northwestern mainland
Mexico tonight.  This disturbance is expected to produce total rain
accumulations of 5 to 10 inches, with isolated maximum amounts of 15
inches across portions of Baja California Sur, Sinaloa, and Sonora
through Thursday. This rainfall may cause life-threatening flash
floods and mudslides.  Moisture from this disturbance will also lead
to areas of heavy rainfall and a risk of flash flooding in the
southwestern United States beginning today.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...50 percent.

2. Another elongated area of low pressure is located about 900 miles
southwest of the southern tip of the Baja California peninsula.
Environmental conditions are expected to be conducive for some
gradual development of this system during the next few days while
it moves slowly west-northwestward or northwestward.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...40 percent.
Forecaster Roth/Blake