March 1, 2018
Summary: Periods of showers continue to move across the San Joaquin Valley, mainly from northern Kings and Tulare Counties northward. As expected, precipitation in the foothills and mountains is constant as a strong west to east flow aloft is lifted by the Sierra Nevada, thus condensing into clouds and eventually heavy precipitation. So far, on day one the south valley is fairly rain free while the west side of the valley is dealing with a rain shadow. All in all, on the valley floor just light amounts have fallen.
The low which is centered just west of the Oregon coastline will continue to pinwheel bands of precipitation through central California from time to time through Saturday. This is a cold system as snow is falling down to 3,500 to 4,000 feet.
As we move into Saturday, the coldest sector of the storm will arrive with snow levels even lower. A pool of cold, unstable air will be above the valley floor so a few thunderstorms cannot be ruled out Saturday afternoon. By Sunday morning, the low will be moving into the Great Basin, ending the precipitation event. The cold air mass following this system may present another challenge with frost coming up Sunday and Monday mornings. Next week, though, will be generally mild. By Tuesday afternoon, temperatures may be moving into the lower 70s and even mid 70s cannot be ruled out in Kern County.
Models are not too bullish on a storm system that may arrive Wednesday into Thursday. They give just a chance of mainly light showers, however one model shows an atmospheric river of air similar to what we saw last winter moving into central and southern California about Thursday. So far, though, this is the odd model out. The new two week model out this afternoon still indicates a pattern overall of below average temperatures with a higher than normal chance of precipitation.
Forecast: Periods of rain tonight through Friday night. Showers and a chance of a few thunderstorms Saturday afternoon. A chance of showers Saturday night, mainly during the evening. Partly cloudy Sunday. Mostly clear Sunday night through Tuesday night. Increasing cloudiness Wednesday leading to a chance of showers Wednesday afternoon through Thursday.
Short Term:
Madera 46/58/41/57
Reedley 45/58/41/58
Dinuba 44/57/40/57
Porterville 44/61/41/58
Lindsay 44/61/41/57
Delano 44/61/42/58
Bakersfield 47/63/43/57
Arvin 46/63/42/58
Taft 46/62/43/59
Lamont 45/62/41/58
Pixley 45/59/40/57
Tulare 44/57/40/57
Woodlake 45/58/41/57
Hanford 45/60/42/58
Orosi 44/57/39/57
Winds: Winds will continue out of the southeast at 10 to 20 MPH at times through Friday night. Stronger gusts are possible along the west side and locally in Kern County. Winds Saturday will be out of the northwest at 10 to 15 MPH with stronger gusts, continuing Saturday night with light winds returning Sunday.
Rain: There will be periods of rain through Friday night as the counterclockwise circulation around a huge low located just off the Oregon coast pinwheels precipitation inland from time to time. So far, we have observed rain shadows on the west side of the valley and in Kern County. On the east side, the potential for rainfall is there for decent totals. I still believe some locations from Porterville northward could pick up between a half inch and an inch of rain before this storm winds down Saturday night. Along the west side, a quarter to a third of an inch seems likely and we’ll use those same numbers for Kern County, though it would be a good idea to keep your fingers crossed on that one. Dry weather will return Saturday night and will last through at least Wednesday morning. Models are not truly optimistic about rain Wednesday afternoon and Thursday. There are variances on timing and intensity. One model actually shows an atmospheric river of air moving into central and southern California, similar to what we experienced last season, but that’s the odd model out. Medium range outlooks going out through the middle of the month are still pointing towards above average rainfall.
Frost Discussion: All locations will be above freezing through Saturday. This is a cold storm we’re now dealing with and an even colder air mass will move down the pipeline from the Gulf of Alaska by Sunday morning. For now, it appears upper 20s to lower 30s are possible Sunday and Monday mornings, but it’s also possible cloud cover may linger behind the exiting storm which would hold temperatures generally in the low to mid 30s. coldest locations could be around 30 degrees or so Tuesday morning then significant moderation will occur at mid week as a mild westerly flow begins. Daytime highs by Tuesday could eclipse the 70 degree mark. Assuming we receive significant amounts of precipitation, which means wet ground, it would also have a tendency to keep temperatures a couple of degrees milder than they would be during a dry spell. Medium range models do not indicate an especially cold period of time coming up, so it looks like Sunday and Monday mornings will be the only troublesome period.
Lows Tonight:
All locations will be above 32 tonight.
Next Report: Friday, March 2