May 17, 2020
Summary: Showers have already spread over much of northern California. Doppler radar is indicating showers as far south as just north of Monterey along the coast and Stockton inland. The parent low is located roughly 250 miles west of the California/Oregon border. This low and its pool of cold, unstable air will move southeastward to a position just to the northwest of the Golden Gate by Monday morning.
A cold front will move down the valley late tonight and Monday morning. behind the front, the air aloft will become progressively colder and more unstable. Thunderstorm development will be possible later Monday afternoon and evening due to the strong daytime heating effect and that cold pool of unstable air aloft. Models track this system right across central California Monday night, meaning the coldest and most unstable portion will be above us during the overnight hours. Models show the center of circulation moving into western Nevada Tuesday morning. it now appears the thunderstorm threat for Tuesday isn’t as great as first though as that cold pool of air may be just far enough to the east to keep most of the action over the Sierra Nevada and possibly the east side of the San Joaquin Valley Tuesday afternoon and evening.
As you might expect, temperatures will dip dramatically beginning Monday as readings fall into the mid 70s and further Tuesday as low 70s can be expected. Temperatures later this week will begin to recover, however model information shows a broad area of low pressure covering much of the western U.S., so even though no inclement weather will occur after Tuesday evening, temperatures will only return to near average to even possibly below.
Forecast: Variable cloudiness today. A chance of showers tonight, mainly from Fresno County north and mainly after midnight. Showers likely Monday and Monday night with a chance of isolated thunderstorms Monday afternoon and evening, generally north of Kern County. A chance of showers Tuesday with a small chance of isolated thunderstorms Tuesday afternoon and evening. Mostly to partly cloudy Tuesday night and Wednesday morning. Mostly clear to occasionally partly cloudy Wednesday night through Sunday.
Short Term:
Madera 86/59/74/52/72 | Reedley 87/58/75/52/73 | Dinuba 85/58/74/53/73 | |
Porterville 87/59/75/53/72 | Lindsay 86/57/75/53/73 | Delano 87/60/76/53/72 | |
Bakersfield 88/62/77/54/72 | Taft 87/64/75/55/71 | Arvin 88/60/75/55/71 | |
Lamont 87/61/76/54/72 | Pixley 86/59/75/53/73 | Tulare 86/59/75/52/72 | |
Woodlake 85/58/75/51/72 | Hanford 87/59/75/52/73 | Orosi 84/57/74/51/72 |
Seven Day Forecast:
Wednesday
Partly cloudy 48/80 |
Thursday
Partly cloudy 51/83 |
Friday
Partly cloudy 50/81 |
Saturday
Partly cloudy 49/80 |
Sunday
Partly cloudy 49/82 |
Two Week Outlook: May 23 through May 29: This model is reverting back to more of a high pressure regime over our region with generally above average temperatures during this period. The chance of rain appears very low.
May: The first month of the dry season will be typically dry, in other words this model is portraying near average precipitation for the month of May. It also appears the trend of above average temperatures will continue for the month.
May, June, July: Obviously, over the next 90 days precipitation will be largely nonexistent with the usual few exceptions, mainly during the month of May. Models show the western half of the U.S. having generally above average temperatures.
Winds Discussion: Winds today will be out of the west at 10 to 20 MPH with stronger gusts. Winds tonight and Monday will be mainly out of the northwest at 10 to 20 MPH with stronger gusts. Winds Monday night through Tuesday will be variable to 15 MPH with stronger gusts near showers or thunderstorms. Winds Wednesday will be generally out of the northwest during the afternoon at 8 to 15 MPH and variable to 8 MPH during the night and morning.
Rain Discussion: The old saying “Timing is everything” certainly applies here. For now, it appears the coldest pool of unstable air will be above the valley floor during the overnight hours Monday, which certainly reduces the chance of thunderstorms. Initially, showers will begin to show up as far south as Fresno County mainly after midnight tonight with scattered showers spreading southward Monday. Even though that pool of cold, unstable air will be just to our northwest Monday afternoon, I still believe there’s a chance of isolated thunderstorms, generally north of Kern County. Most models place that cold unstable air over western Nevada Tuesday morning, reducing the chance of precipitation. Even so, I believe I should keep a chance of showers in the forecast for Tuesday, especially along the west side of the valley, with a minimal risk of thunderstorms.
Rainfall amounts will be quite spotty with most locations along the west side and in Kern County recording less than .10. Generally east of Highway 99 fro m Tulare County north, upwards of .25 cannot be ruled out. If thunderstorms occur, more than .50 will be possible in those isolated locations.
Dry weather will return Tuesday night and continue for the remainder of the week.
Afternoon Dew Points Today: Low to mid 50s. Kern: Low to mid 50s. Humidity values ranging from 30%/90% at Hanford. Bakersfield 30%/80%
Actual Humidity range May 16, 2020: Delano, 82%/29%, Porterville, 85%/28%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 50%, tomorrow 20%. Bakersfield: Today: 70% Tomorrow: 20%
ET Rates Over the Past Seven Days: Stratford NA, Parlier 1.76, Blackwell Corner 1.94, Arvin 1.83, Orange Cove NA, Porterville 1.74, Delano 1.81. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford NA, Parlier 72, Blackwell 76, Arvin, 72, Orange Cove NA, Porterville 78, Delano 76
Record Temperatures: 106/44. Average Temperatures: 85/54
Cooling Degree Days this Season: 157 +61
Courtesy of the NWS
Average temperature for May so far: 70.0 +3.0
Precipitation: Seasonal total for Fresno/average + or 7.51 or -3.42. Month to Date: .00 -.26
Since Oct 1, 2019, Bakersfield: 7.03, or +.82. Month to Date: .01 -.11
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove, Parlier, Arvin, Shafter, Stratford, Delano, Lindcove, Porterville
Hours at 45 or below 45.
Sunrise: 5:49, Sunset: 8:02 pm. Hours of Daylight: 14:12
Yesterday’s Weather:
MCE : Merced 153 : DH1700 / 87 / 54 / 0.00 /
MAE : Madera 253 : DH1700 / 86 / 50 / 0.00 /
FAT : Fresno Airport 333 : DH1700 / 87 / 60 / 0.00 /
HJO : Hanford Airport 242 : DH1700 / 87 / 54 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1700 / 88 / 50 / 0.00 /
BFL : Bakersfield Airport 496 : DH1700 / 84 / 59 / 0.00 /
VIS : Visalia Airport 292 : DH1700 / 86 / 54 / 0.00 /
ATEC1 : Avenal 787 : DH1648 / 85 / 54 / 0.00 /
PTV : Porterville Airport 442 : DH1700 / 85 / 53 / 0.00 /
TFTC1 : Taft 759 : DH1651 / 83 / 60 / 0.00 /
Rainfall: 24hr W.Y. % Last Y. % Ave. Year ave.
STOCKTON 0.00 7.99 59 16.75 124 13.47 14.06
MODESTO 0.00 6.86 55 12.76 102 12.46 13.11
MERCED 0.00 9.34 78 12.43 104 11.90 12.50
MADERA 0.00 5.81 51 10.45 92 11.42 12.02
FRESNO 0.00 7.51 69 10.31 94 10.93 11.50
HANFORD 0.00 6.51 68 8.02 84 9.58 10.10
BAKERSFIELD 0.00 7.03 113 6.56 106 6.21 6.47
BISHOP 0.00 2.25 51 8.37 190 4.40 5.18
SALINAS 0.00 9.06 73 12.86 104 12.41 12.83
PASO ROBLES 0.00 11.34 92 14.32 116 12.35 12.78
SANTA MARIA 0.00 10.42 76 15.05 110 13.63 13.95
Next report: May 18/morning