September 8, 2017
Summary: We have a definite rain threat on our hands for late Saturday night through Monday. Forecast models did a good job in showing the formation of a cut off low just off the coast of Monterey. Currently, there’s no active weather associated with this low, however that will change, especially during the second half of the weekend and early next week as models continue to pick up on a significant burst of monsoonal moisture moving northward. The winds aloft are now out of the south/southwest, but the winds aloft will likely become south to southeast, moving moisture into southern California and eventually central California. With the low in fairly close proximity to the valley, and plenty of moisture moving northward, there may be enough convection for scattered showers and thunderstorms over the valley floor with the greatest risk being in Kern and Tulare Counties.
Models show this mess moving southward by Tuesday and then northward along the coast then inland late Wednesday night and Thursday. Models differ on the situation somewhat. Some show it moving inland as a low pressure system while others forecast that it will be picked up by a significant trough of low pressure moving inland Thursday and Friday. in any case, we’ll watch this closely and update as necessary, but at the very least there will be a nice cool down with temperatures after Wednesday likely being in the mid to upper 80s.
Forecast: Mostly clear through Saturday with occasional cloudiness. Increasing cloudiness Saturday night with a reasonable chance of scattered showers and isolated thunderstorms, mainly Sunday and Monday. A slight chance of showers Monday night. Becoming partly cloudy Tuesday and Wednesday. Variable cloudiness at times Wednesday night through Thursday. Mostly clear Friday.
Short Term:
| Madera 91/61/92/62/95 | Reedley 92/63/92/65/94 | Dinuba 92/62/92/65/93 | |
| Porterville 93/63/93/67/91 | Lindsay 93/61/93/64/92 | Delano 93/65/93/68/92 | |
| Bakersfield 93/68/93/71/90 | Arvin 94/67/93/70/90 | Taft 92/73/92/75/91 | |
| Lamont 94/68/93/72/92 | Pixley 93/64/93/69/91 | Tulare 92/62/92/69/90 | |
| Woodlake 92/63/93/68/90 | Hanford 92/64/92/69/91 | Orosi 91/62/92/68/91 | |
Seven Day Forecast:
| Monday
Chance of showers 72/91 |
Tuesday
Partly cloudy 66/92 |
Wednesday
Partly cloudy 61/89 |
Thursday
Partly cloudy 61/89 |
Friday
Mostly clear 59/87 |
Two Week Outlook: September 15 through September 21: For a change, a trough of low pressure shows up on this model along the Pacific coast. It’s very doubtful any precipitation will occur with this trough, but it will lower temperatures to near to possibly somewhat below average.
September: This model shows upper level high pressure more dominant over the western U.S. There’s no clear indicator of above or below average rainfall as we move into the fall season. With that in mind, we’ll call for near average precipitation for the month.
September, October, November: It appears temperatures overall will rise to above average values for the bulk of this time frame. Upper level high pressure is also more dominant with precipitation, believe it or not, predicted to be somewhat near average.
Winds: Winds will be generally less than 15 MPH through Monday and mainly out of the northwest afternoons and evenings.
Rain: We have a fairly significant possibility of rain, especially for late Saturday night through Monday. A cut off low has now developed off the central coast. Currently, it’s not visible until looking at water vapor satellite imagery. In the meantime, a big batch of monsoon moisture is moving northward through northern Mexico and is already affecting extreme southern California. If models are correct, this moisture will become entrained in the circulation of the off shore low. My main concern is that this low could add convection to the atmosphere which very well could sustain scattered showers and thunderstorms, especially in the south valley.
The time of greatest risk will be Sunday through Monday evening. Dry weather will return Tuesday as the low shifts southward, but the low will track northward again Wednesday and Thursday before being absorbed into a trough of low pressure tracking through the Pacific Northwest and northern California.
For now, I want to keep the forecast dry for Wednesday through Thursday night, but that is subject to change as it will depend on the exact track of the system. By Friday, a trough of low pressure will move through for dry weather which should last through at least the middle of the following week.
Afternoon Dew Points Today: Mid to upper 50s. Kern: Mid to upper 50s
Relative Humidity Forecast: Hanford, 30%/80% Bakersfield, 30%/65%
Actual Humidity September 6, 2017: Delano, 77%/29%, Porterville, 75%/26%
Percentage of Sunshine Today/Tomorrow: Visalia: Today 100% tomorrow 70%, Bakersfield: Today 100% tomorrow 60%.
ET Rates Over the Past Seven Days September 6, 2017: Stratford 1.75, Parlier 1.39, Blackwell 1.90, Lindcove 1.42, Arvin 1.61, Orange Cove 1.62, Porterville 1.46, Delano 1.54, Madera Two 1.41 Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 78, Parlier 85, Blackwell 83, Lindcove 80, Arvin 1.89, Orange Cove 83, Porterville 87, Delano 84, Madera Two 84
Mean Temperatures for September Month So Far: 87.0+11.0
Record Temperatures: 108/50. Average Temperatures: 93/62
Cooling Degree Days This Season: 1950, +553 Courtesy of the NWS
Precipitation: Seasonal total/average/above or below average:
Since September 6, 2017 Fresno: 17.20 season. / +5.86 or +5.86 Month to Date: T
Since September 6, 2017 Bakersfield: 7.89, or 1.45, Month to Date: .01, Water year season is from October 1st through September.
Chilling Hours November 1st Through February 28: Orange Cove, Parlier, Arvin, Shafter, , Stratford, Madera two, Alpaugh, Delano, Lindcove, Porterville, Hours at 45 or below 45.
Sunrise: 6:36 am Sunset: 7:16 Hours of Daylight: 12:43
Yesterday’s Weather
MCE : Merced 153 : DH1700 / 86 / 65 / 0.00 /
MAE : Madera 253 : DH1700 / 90 / 66 / 0.00 /
FAT : Fresno Airport 333 : DH1700 / 92 / 68 / 0.00 /
HJO : Hanford Airport 242 : DH1700 / 92 / 67 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1700 / 94 / 69 / 0.00 /
VIS : Visalia Airport 292 : DH1700 / 91 / 65 / 0.00 /
ATEC1 : Avenal 787 : DH1605 / 90 / 66 / 0.00 /
PTV : Porterville Airport 442 : DH1700 / 93 / 65 / 0.00 /
TFTC1 : Taft 759 : DH1619 / 91 / 70 / 0.00 /
LOSC1 : Los Banos 120 : DH1600 / 87 / 66 / 0.00 /
Rainfall:
To date Last year Average Annual ave
STOCKTON 0.00 21.79 158 16.69 121 13.79 14.06
MODESTO 0.00 16.93 132 15.61 121 12.87 13.11
MERCED 0.00 16.03 131 14.66 120 12.24 12.50
MADERA 0.00 14.18 120 12.96 110 11.79 12.02
FRESNO 0.00 17.20 152 14.29 126 11.34 11.50
HANFORD 0.00 11.05 111 8.26 83 9.94 10.10
BAKERSFIELD 0.00 7.83 122 5.43 85 6.40 6.47
BISHOP 0.00 9.18 183 3.88 77 5.01 5.18
SALINAS 0.00 16.45 130 13.47 106 12.67 12.83
PASO ROBLES 0.00 16.16 129 8.06 64 12.57 12.78
SANTA MARIA 0.00 18.69 135 9.00 65 13.83 13.95
Rainfall season from October 1st through September 30th
Next Report: Saturday, September 9