Showers and thunderstorms remain in the forecast into early Thursday

Skies over the SLO Airport 5-2-23
Posted at 3:39 PM, May 02, 2023

Our storm system is progressing as expected. Activity did pick up today in an on-and-off fashion with mostly lighter showers, but some brief downpours did take place. This is all taking place as the surface low of this storm is still dropping into the area. Currently, the region is under a larger trough of low pressure which has been enough to produce the rainfall we’ve seen so far, but the dynamics for rain and thunderstorms increase dramatically Wednesday as the system begins to intersect the Central Coast.

Not only will showers increase but thunderstorm potential also increases. Today there was an interesting new twist to that as high temps Wednesday should be in the mid-60s and some low 70s just before the system drops in. This is important as the warmer surface temps actually increase the instability of the system.

The storm already had plenty of cold air aloft and this will increase the lapse rate, in other words, the contrast between the surface temps and the upper air temps. This can increase the vertical velocity of air parcels, increasing the thunderstorm potential.

Thunderstorms introduce the possibility of brief heavy downpours and winds, hail, waterspouts, and even small tornadoes.

This potential exists into early Thursday morning when the surface low starts to slide out of the area. A few widely scattered showers could pop up into the evening but the activity will significantly wane.

Our forecast for rain accumulation remains unchanged, up to 1” of rain. There will likely be the greatest potential for the Southcoast and for any S-SW facing slope. The interior still looks to see the lowest rain totals.

Snow levels for the system are above 4500ft. This could put snow on the Tejon Pass in the region and the highest elevations of the Santa Barbara and Ventura County Mountains.

After this system departs there will still be a trough over The West, so temps will recover but slowly.

The deeper extended forecast looks dry locally but regionally the PacNW Should see a series of fast-moving fronts and occasional showers, this will be enough to stop high pressure from setting up so the 8-14 day expectation on temps is below average.