May 8, 2019
Summary: We will see a sneak attack through the back door beginning in another 18 to 20 hours or so. A weak low currently over the Great Basin will actually retrograde. Instead of moving from west to east as most storms do at this latitude, this one will move from east to west then will form a closed low just off the central coast Friday and Friday night. models this afternoon continue to be bullish not only on the likelihood of measurable rain, but quantities, as well. The outlier models on the valley floor indicate more than an inch of rain will fall in most locations while the more reasonable ones predict anywhere from .10 to as much as .50. Those models seem to be more plausible at this time. It will be a slow mover, chugging very slowly just off the central coast Friday night and off the southern California coast Saturday.
Thunderstorms, locally heavy, are likely over the mountain areas and I would not rule out a few cells over the valley floor, especially Friday afternoon and Friday night when the coldest, most unstable portion of this event will be overhead. The main threat from these storms will obviously be lightning and localized heavy rain as any storms that do develop will be slow movers.
The chance of showers will continue into Saturday morning then decrease Saturday afternoon as the storm moves further south. By early Sunday, the center of circulation will be crossing northern Baja, ending precipitation threats for the valley.
Medium range models which had suggested more unsettled weather by the middle of next week are backing off on that possibility to a degree. After the Thursday night through Saturday event, dry weather should return for a while. I must say, however, for this late in the season the two week model shows an unusually strong signature for rain for central California, especially about the 18 through the 20 with temperatures solidly below average.
Forecast: Other than occasional high clouds over the first half of the night, it will be mostly clear. Becoming partly cloudy after midnight. Increasing clouds Thursday morning leading to a chance of showers Thursday afternoon, especially towards sunset. Periods of clouds likely Thursday night through Friday night with a chance of locally heavy thunderstorms. A chance of showers Saturday, mainly during the morning. Mostly to partly cloudy Saturday night through Sunday morning. Mostly clear Sunday afternoon through Monday with lingering clouds over Kern and Tulare Counties. Mostly clear to occasionally partly cloudy Monday night through Wednesday.
Temperatures: Lows tonight will range in the mid 50s to the mid 60s. highs Thursday will warm into the lower 80s. lows Thursday night will cool into the upper 50s and lower 60s. Highs Friday will range in the upper 50s to the mid 60s.
Next Report: Thursday, May 9