Posted January 17, 2010, 4:54 PM.

This is the first in a series of storms coming this week that has led the National Weather Service and others to issue remarkable forecasts.

The consistent prediction has been for four to eight inches in the coastal regions for the week, with up to twenty inches of rainfall on the wetter slopes and accumulations of several feet of snow at higher elevations.

Inland valley totals tend to run higher than the coastal predictions, so figure between six and eight inches for the wetter inland communities, which tend to be in the west (Temecula, Murrieta, Wildomar, Lake Elsinore, De Luz and Fallbrook). Areas further to east (Menifee, Perris, Moreno Valley, Riverside, Hemet and San Jacinto) should be more to the lower end of the prediction if the storms track classically from the southwest.

Several factors have led to the extremely wet predictions. The first is a lot of tropical moisture being fed north into the storms in the middle of the Pacific Ocean, enhancing their rain potential. The El Nino condition in the equatorial region could be helping to drive this.

The second factor is the jet stream, which has dropped south over Southern California. It looks like that element will stay in place for at least a week, perhaps more.

Some showers were possible Sunday night, although nothing heavy was expected. Heavy rain was likely by afternoon or evening on Monday, with scattered showers lingering through Tuesday.

Snow levels from the first storm were expected to be near 8,000 feet initially, then drop to about 6,000 feet.

Showers were predicted to increase Tuesday night as the second, weaker storm arrives.

The final two storms of the week have been advertised as the strongest. Storm #3 was anticipated to bring heavy rain Wednesday night, and storm #4, the strongest, has heavy rain predicted for Thursday and perhaps into Friday.

If the predictions come to pass, creek flooding will be a near certainty this week, especially later in the week.

It's possible there will be a break Saturday, followed by storms currently timed for Sunday and yet another deeper into the following week.