September 25, 2018
Summary: A sharp high at the upper levels of the atmosphere extends from the Pacific coast northward into the Gulf of Alaska while a developing low is roughly a thousand miles off the central coast. The high will begin to slowly shift inland through Thursday for yet another warming trend. The marine layer remains at 1,500 feet at Monterey, but the difference in pressure between the coast and the interior is almost flat. In fact, winds in the Delta at last report were dead calm.
The warm up will peak Thursday as warmest locations push the century mark. that low I alluded to well off shore will begin to approach the coast Friday and slowly move inland through northern California Saturday and Sunday. No precipitation is expected from this system, however a major cooling trend will occur as pressures fall and a strong on shore flow pushes a good surge of that marine air inland. By Sunday night, this system will have moved into the interior west, however a new low is projected to develop off the central coast Monday. On paper, this appears to be a fairly significant feature which, in itself, could present a small chance of showers and thunderstorms, especially over the mountains.
Models have been pretty consistent in showing a weakening hurricane moving up the Baja coast and possibly inland through extreme northern Baja, or even extreme southern California, about Tuesday. If this feature does develop heavy precipitation would be likely over southern California, especially over the mountains and the lower desert regions.
Where the forecast gets really tricky is in the position of that low off the central coast. The counterclockwise circulation around the low could possibly pick up moisture from the south and pull it along the eastern side of this feature. That would pose an increasing chance of showers and possibly even some thunderstorms about Monday night or Tuesday. Since there is a trend on some models, I feel it necessary to introduce at least a slight chance of measurable rain to the forecast beginning late Monday afternoon and lasting through at least Tuesday. A lot could change between now and then but for now I feel it’s warranted to add that small chance of precipitation to the forecast.
Forecast: Mostly clear skies through Friday night. Mostly clear to possibly occasionally partly cloudy Saturday through Sunday night. Variable cloudiness Monday through Tuesday with a slight chance of showers and thunderstorms late Monday afternoon through Tuesday.
Short Term:
| Madera 93/56/96/56/97 | Reedley 93/55/97/57/98 | Dinuba 92/54/95/56/97 | |
| Porterville 94/55/97/57/98 | Lindsay 94/55/97/56/98 | Delano 93/59/96/60/99 | |
| Bakersfield 93/65/96/67/99 | Arvin 94/61/97/63/100 | Taft 94/66/96/68/99 | |
| Lamont 94/62/97/64/99 | Pixley 93/56/96/57/97 | Tulare 92/54/96/57/97 | |
| Woodlake 92/55/96/57/97 | Hanford 94/56/97/58/98 | Orosi 92/55/95/56/97 | |
Seven Day Forecast:
| Friday
Mostly clear 61/96 |
Saturday
Partly cloudy 56/85 |
Sunday
Partly cloudy 52/84 |
Monday
PM showers possible 54/84 |
Tuesday
Chance of showers 54/80 |
Two Week Outlook: October 1 through October 7: Models are actually quite interesting for this time period. A significant area of low pressure will be off the west coast. Some models are suggesting a chance of showers. About a week from Wednesday, some models are showing a tropical system becoming involved, in which case rain would be likely. For now, that’s in the very low chance category. Temperatures should be near to marginally below average.
September: This model indicates there will be a higher than active monsoon over the Desert Southwest and possibly central and southern California. This typically does not affect the valley floor other than cloud cover but could result in a larger number of days of thunderstorms over the Sierra Nevada and possibly even the Kern County mountains. With generally high pressure over the southwest, temperatures will likely be somewhat above seasonal average.
September, October, November: The first part of this time frame will see a more active than usual monsoon in place for above average rain over the Sierra Nevada and possibly the mountains and deserts of southern California. October and November’s conditions aren’t as easy to determine. At this time we’ll call for generally average values for both rain and temperatures.
Winds: Winds will be mainly less than 12 MPH through Thursday. Winds Friday will be mainly out of the west or northwest at 10 to 15 MPH with local gusts to near 30 MPH along the west side during the later afternoon or evening hours.
Rain: Expect dry weather through at least Monday morning. Beginning late Monday afternoon through at least Tuesday, I cannot completely rule out a chance of showers and/or thunderstorms. We have quite an interesting weather scenario possibly setting up. Some models indicate a significant area of low pressure will be just off the central coast Monday night and Tuesday. In the meantime, there are a couple of models showing a hurricane rapidly weakening and possibly moving on shore over extreme northern Baja or even extreme southern California. This model solution would result in significant precipitation for southern California.
Where our forecast becomes dicey is whether or not the low off the central coast dig far enough to the south to begin rotating tropical moisture northward into the valley. The best chance, although still low, would be in Kern County, however the remainder of the growing area would entertain a small risk, as well. There have been certain trends on some models showing this solution as viable. Since there are shaky trends on models, I want to add a small chance of showers or thunderstorms to the forecast for late Monday afternoon through at least Tuesday. It’s also possible the majority of this moisture will move inland south of the Kern County mountains. However, with that low off shore, at least a small chance of showers is possible.
Afternoon Dew Points Today: Mid to upper 40s. Kern: Low to mid 40s.
Humidity: Visalia: 20%/70% Bakersfield: 15%/50%
Actual Humidity September 24, 2018: Delano, 86%/19%, Porterville, 73%/18%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 100% tomorrow 100% Bakersfield: Today: 100% Tomorrow: 100%
ET Rates Over the Past Seven Days: Stratford 1.47, Parlier 1.31, Blackwell 1.47, Lindcove 1.29, Arvin 1.51, Orange Cove 1.45, Porterville 1.20, Delano 1.33, Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 70, Parlier 72, Blackwell 81, Lindcove, 73, Arvin, 72, Orange Cove 73, Porterville 78, Delano 71
Record Temperatures: 100/43. Average Temperatures: 88/56
Cooling Degree Days this Season: 2001 +448
Courtesy of the NWS
Average temperature for September so far: 75.6 +1.4
Precipitation: Seasonal total/average/above or below average:
Since Oct 1, 2017 Fresno: 6.73 season. or -4.71. Month to Date: .00
Since Oct 1, 2017, Bakersfield: 3.93, or -2.50. Month to Date: .00
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove, Parlier, Arvin, Shafter, Stratford, Madera two, Lindcove, Porterville, Hours at 45 or below 45.
Sunrise: 6:50 am Sunset: 6:50 pm. Hours of Daylight: 12:00
Yesterday’s Weather:
MAE : Madera 253 : DH1700 / 95 / 53 / 0.00 /
FAT : Fresno Airport 333 : DH1700 / 92 / 62 / 0.00 /
HJO : Hanford Airport 242 : DH1700 / 94 / 53 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1700 / 93 / 54 / 0.00 /
BFL : Bakersfield Airport 496 : DH1700 / 94 / 64 / 0.00 /
VIS : Visalia Airport 292 : DH1700 / 91 / 52 / 0.00 /
ATEC1 : Avenal 787 : DH1651 / 91 / 61 / 0.00 /
PTV : Porterville Airport 442 : DH1700 / 91 / 55 / 0.00 /
TFTC1 : Taft 759 : DH1649 / 91 / 67 / 0.00 /
LOSC1 : Los Banos 120 : DH1600 / 94 / 58 / 0.00 /
Rainfall: Water year Oct 1st through September 30th
Year % Last Y. % Ave. Annual ave.
STOCKTON 0.00 9.22 66 21.79 156 13.97 14.06
MODESTO 0.00 8.17 63 16.93 130 13.02 13.11
MERCED 0.00 7.06 57 16.05 129 12.43 12.50
MADERA 0.00 7.22 60 14.26 119 11.96 12.02
FRESNO 0.00 6.73 59 17.36 152 11.44 11.50
HANFORD 0.00 4.70 47 11.21 112 10.05 10.10
BAKERSFIELD 0.00 3.95 61 8.34 129 6.45 6.47
BISHOP 0.00 3.08 60 9.18 179 5.12 5.18
SALINAS 0.00 7.16 56 16.49 129 12.77 12.83
PASO ROBLES 0.00 9.62 76 16.17 127 12.70 12.78
SANTA MARIA 0.00 6.01 43 18.91 136 13.91 13.95
Next report: Wednesday, September 26