Wednesday, January 4, 2017

Atmospheric river ahead?

This forecast hasn't changed much in the last 36 hours.

It's still 72 hours away, but check this out:

By Friday night, another abrupt change in the forecast pattern is expected as deeper moisture begins to advect inland from the eastern Pacific. Light rain remains on track to spread inland late in the night into Saturday morning. During the day Saturday, PWAT values are forecast to increase as an atmospheric river (AR) sets aim at the central California coast. By Saturday night into Sunday, PWAT values are forecast to approach 1.50" and will likely result in widespread moderate to locally heavy rainfall. The AR is forecast to move very little from Saturday night through Sunday and will likely lead to 24 to 36 hours of steady rainfall across the region. At this time, it appears the focus for the heaviest precipitation will be south of San Francisco along the coastal ranges which have the potential to pick up more than 12.00" of rainfall through the weekend. Given the impressive amounts of precipitation recorded in the Santa Cruz and Santa Lucia Mountains from this past system (Tuesday into Wednesday morning) cannot rule out even greater rainfall totals exceeding 15.00" as the upcoming AR event has the potential to be much stronger. Meanwhile, many urban locations can expect anywhere from 2.00" to 5.00" of precipitation through the weekend. In addition, breezy to gusty winds are forecast from Saturday night into Sunday as surface low pressure approaches the coast and pushes inland to the north. This south/southeast flow will also help to enhance precipitation rates along the coastal ranges. Be sure to stay up to date with the latest information regarding this upcoming weekend`s storm system as we will continue to refine our forecast in the coming days.

5 inches of rainfall in urban areas in 3 days?

15 inches of rainfall in the mountains in 3 days?

Remember, Oakland CA averages only 24 inches of rainfall for the entire YEAR, so getting 20 percent of the yearly total in just 3 days is, what, astounding?

Check back here in a week for the outcome, unless I'm paddling around in a boat somewhere...

No comments:

Post a Comment