March 2, 2019
Summary: Moderate to heavy rain is falling from the Monterey/San Luis Obispo line southward to Santa Barbara County, as of the time of this writing. This feed continues inland through much of Kings County and western Tulare County and northwest Kern County while points north and south of that zone have lighter showers occurring. This is the zone with the atmospheric river of air we’ve been discussing. Models still indicate that from tonight through Wednesday night, places like Porterville could exceed two inch totals, though these are simply models and Mother Nature is going to do what she’s going to do. Embedded with this flow are isolated thunderstorms which will result in brief periods of very heavy rain.
This so-called atmospheric river will continue across the southern half of the San Joaquin Valley tonight and for a time Wednesday morning. The cold frontal portion of this powerful storm will move slowly down the valley, nudging the AR south, as well. By Wednesday afternoon, the main feed of tropical juice will be roughly from the Kern County mountains southward. That will not, however, by any means end the precipitation as showers and a chance of thunderstorms will continue. Any thunderstorms will be accompanied by locally heavy rain and small hail.
The showers will taper off later Wednesday night and there may actually be a few hours of dry weather Thursday. However, the chance of much lighter showers will increase Thursday afternoon through Friday evening as a low moves across central and southern California. This system will be considerably colder with snow levels in the mountains dropping to between 3,000 to 4,000 feet.
Friday night through at least Sunday morning will be dry then a new low will drop southward out of the Gulf of Alaska. Whether or not we receive precipitation from this event will be determined by how far off shore the low tracks on its journey southward off the California coast. For now, it looks like there’s roughly a 30% chance of showers Sunday night and Monday with the greatest risk along the west side of the valley. This system will ultimately move inland through northern Baja Monday evening then it will finally allow upper level high pressure to begin to build in from the west by Tuesday.
From Tuesday through next weekend, it would appear upper level high pressure will govern our weather in one way, shape, or form. Overall, a northwest flow will prevail, maintaining near to somewhat below average temperatures. Medium range models for the following week are also indicating there’s an excellent chance of dry weather.
Forecast: Rain tonight, possibly heavy at times, with a chance of thunderstorms. Rain possibly heavy at times for a time Wednesday morning. Rain turning to showers after nine or ten AM. Showers and a chance of thunderstorms Wednesday afternoon and evening. Showers tapering off after midnight Wednesday night with a brief lull in the showers Thursday morning but with an increasing chance of lighter showers Thursday afternoon. Showers Thursday night through Friday evening then becoming partly to mostly cloudy. Partly cloudy Saturday morning. Becoming mostly clear to occasionally partly cloudy Saturday afternoon through Sunday morning. Variable cloudiness late Sunday afternoon through Monday evening with a small chance of showers. Partly to mostly cloudy Monday night through early Tuesday. Becoming mostly clear Tuesday afternoon.
Short Term:
Madera 55/65/51/63 | Reedley 56/65/50/64 | Dinuba 55/64/50/63 | |
Porterville 56/66/51/64 | Lindsay 56/66/52/63 | Delano 57/67/53/63 | |
Bakersfield 58/69/53/63 | Taft 57/68/53/63 | Arvin 56/68/53/62 | |
Lamont 57/67/52/63 | Pixley 56/67/52/62 | Tulare 55/65/51/62 | |
Woodlake 55/65/51/62 | Hanford 56/66/52/63 | Orosi 54/65/51/62 |
Winds: Winds in the south valley over the next two to three hours will be mainly out of the northwest at 15 to 25 MPH with stronger gusts. Later this evening through Wednesday morning, winds will be mainly out of the southeast at 15 to 30 MPH with gusts to 40 MPH possible along the west side. In Kern County, gusts in excess of 50 MPH will be possible near the base of the Kern County mountains. Winds Wednesday afternoon through Wednesday night will be mainly out of the west to southwest at 10 to 20 MPH with stronger gusts in the vicinity of showers and especially thunderstorms. Winds Thursday through Friday will generally be in the 10 to 15 MPH range with stronger gusts, especially in the vicinity of showers.
Rain: the pace of the rain is now increasing, especially from Fresno County southward which is now finally under the atmospheric river of air which has been so widely advertised. Visible on radar are red patches which indicates areas of moderate to heavy rain. No doubt a few lightning strikes are accompanying these areas. The AR is forecast by models to pretty much be in place through early Wednesday, so theoretically we should observe a train of rain, moderate to heavy at times, through the night and into Wednesday morning. Don’t be surprised if you hear a roll of thunder or two at any given time.
The rain will break off into showers later Wednesday morning through late Wednesday evening. The risk of isolated to scattered thunderstorms will be relatively high Wednesday afternoon and evening. If these storms do occur, localized very heavy rain and small hail can be expected.
Showers will taper off later Wednesday night and for a time Thursday morning. Lighter showers will then overspread the valley from another system, this time with no pineapple connection. Dry weather will return Friday night and will last through at least Sunday morning with only a minimal chance of showers late Sunday afternoon through early Monday.
Latest short term high resolution models still indicate between one and two inches of rain are possible over the southern half of the San Joaquin Valley tonight through Wednesday night. Much lighter amounts of precipitation are expected Thursday and Friday.
Beyond Monday of next week, models continue to trend towards dry weather and possibly well into the following week.
Frost Discussion: All locations will be above freezing for the foreseeable future.
Next report: Wednesday morning/March 6