September 12, 2017
Summary: An upper low jogged a bit further north overnight and is centered roughly 300 miles to the west/southwest of Monterey. The active portion of this storm continues to be over its far eastern and northern flanks. That has put showers over northern California and left central and southern California largely free of clouds. The chance of measurable rain at any given location is quite small through Wednesday. As the low begins to approach the coast tonight and Wednesday, thunderstorms will break out over the Sierra Nevada and possibly even over the Coast Range.
By early Thursday morning, the low will be absorbed by a significant trough of low pressure moving through the Pacific Northwest and California. This will result in a dramatic cool down as initially marine air will surge inland as a strong onshore flow develops. A considerable cooler air mass will then engulf California, moving temperatures into the mid to upper 80s as early as Thursday. Even tomorrow, temperatures will struggle to reach the 90 degree mark.
The trough could lower temperatures into the lower 80s by Friday then temperatures will slowly move upward again over the weekend as the trough moves to the east. Models show another trough moving into the Pacific Northwest and northern California by Monday for another cool down, although this early in the year no precipitation is expected.
Short term, the winds aloft continue to be out of the south, but will become southwesterly tonight and northwesterly by Wednesday night. All the key ingredients are there to bring a touch of fall to the region with largely below average temperatures Wednesday through Friday and again Monday through Wednesday of next week.
A tropical system is expected to develop south of Cabo San Lucas by Sunday and move perhaps half way up the peninsula. For now, I don’t anticipate any problems from this storm as the winds aloft during this time frame will be out of the west to southwest with all the moisture going into eastern Arizona and New Mexico.
Forecast: Mostly clear with occasional cloudiness through Wednesday night with a slight chance of isolated showers and thunderstorms, mainly near the foothills. Mostly clear and cooler Thursday through Friday. mostly clear Friday night through Tuesday.
Short Term:
Madera 96/66/89/65/85 | Reedley 97/67/89/63/87 | Dinuba 95/65/89/63/86 | |
Porterville 96/66/90/65/87 | Lindsay 96/65/89/64/86 | Delano 97/67/90/63/87 | |
Bakersfield 97/70/89/67/87 | Arvin 98/68/91/65/87 | Taft 96/74/90/67/85 | |
Lamont 98/70/91/66/88 | Pixley 96/66/91/63/87 | Tulare 95/65/89/63/86 | |
Woodlake 96/65/90/62/86 | Hanford 96/65/90/63/87 | Orosi 95/65/91/62/86 |
Seven Day Forecast:
Friday
Mostly clear 57/82` |
Saturday
Mostly clear 59/89 |
Sunday
Mostly clear 61/90 |
Monday
Mostly clear 57/84 |
Tuesday
Mostly clear 56/82 |
Two Week Outlook: September 18 through September 24: This model shows a pretty active pattern moving into the Pacific Northwest and clipping northern California. For now, it does not appear precipitation will affect central California, but this regime should keep temperatures near to slightly 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 today and tonight then will be out of the northwest at 5 to 15 MPH Wednesday and Thursday with locally stronger gusts. Gusts to around 25 MPH are possible below some of the gaps and passes along the I5 corridor. Expect light winds to return Friday.
Rain: The active portion of an upper low just off the central coast hash moved into northern California, so the chance of measurable rain at any given location is quite low. The low will begin to track across the region Wednesday, maintaining a chance of thunderstorms over the Sierra Nevada and a possible cell or two over the Coast Range, though that’s a minimal chance.
The best forecast seems to be a slight chance of isolated showers or thunderstorms near the foothills through Wednesday, although the vast majority of the territory will remain dry. A new trough of low pressure will move through Thursday with no active weather. But, it will be the first real taste of fall as temperatures plummet into the mid 80s.
Conditions for Thursday and beyond will be dry.
Afternoon Dew Points Today: Upper 50s to the lower 60s. Kern: Mid to upper 50s.
Relative Humidity Forecast: Hanford, 30%/75% Bakersfield, 30%/60%
Actual Humidity September 10, 2017: Delano, 83%/31%, Porterville, 84%/27%
Percentage of Sunshine Today/Tomorrow: Visalia: Today 80% tomorrow 80%, Bakersfield: Today 90% tomorrow 90%.
ET Rates Over the Past Seven Days September 10, 2017: Stratford 1.57, Parlier 1.29, Blackwell 1.59, Lindcove 1.32, Arvin 1.50, Orange Cove 1.50, Porterville 1.27, Delano 1.41, Madera Two 1.31 Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 78, Parlier 83, Blackwell 82, Lindcove 79, Arvin 1.89, Orange Cove 82, Porterville 86, Delano 82, Madera Two 84
Mean Temperatures for September Month So Far: 84.2 +8.5
Record Temperatures: 111/44. Average Temperatures: 92/62
Cooling Degree Days This Season: 2011, +574 Courtesy of the NWS
Precipitation: Seasonal total/average/above or below average:
Since September 10, 2017, Fresno: 17.20 season. or +5.85. Month to Date: T
Since September 10, 2017, Bakersfield: 7.89, or 1.43, 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: 6:39 am Sunset: 7:10 Hours of Daylight: 12:36
Yesterday’s Weather
MCE : Merced 153 : DH1700 / 96 / 68 / T /
MAE : Madera 253 : DH1700 / 96 / 71 / T /
FAT : Fresno Airport 333 : DH1700 / 95 / 73 / T /
HJO : Hanford Airport 242 : DH1700 / 98 / 67 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1700 / 98 / 72 / 0.00 /
BFL : Bakersfield Airport 496 : DH1700 / 100 / 77 / T /
VIS : Visalia Airport 292 : DH1700 / 97 / 68 / 0.00 /
ATEC1 : Avenal 787 : DH1656 / 94 / 76 / 0.00 /
PTV : Porterville Airport 442 : DH1700 / 97 / 68 / 0.00 /
TFTC1 : Taft 759 : DH1652 / 98 / 75 / M /
LOSC1 : Los Banos 120 : DH1600 / 96 / 74 / T /
Rainfall:
To date Last year Average Annual ave
STOCKTON T 21.79 158 16.69 121 13.82 14.06
MODESTO 0.00 16.93 131 15.61 121 12.89 13.11
MERCED T 16.03 131 14.66 119 12.28 12.50
MADERA T 14.18 120 12.96 110 11.83 12.02
FRESNO T 17.20 151 14.29 126 11.36 11.50
HANFORD 0.00 11.05 111 8.26 83 9.97 10.10
BAKERSFIELD T 7.83 122 5.43 85 6.41 6.47
BISHOP T 9.18 183 3.88 77 5.02 5.18
SALINAS 0.04 16.49 130 13.47 106 12.68 12.83
PASO ROBLES 0.01 16.17 129 8.06 64 12.58 12.78
SANTA MARIA T 18.91 137 9.00 65 13.84 13.95
Rainfall season from October 1st through September 30th
Next Report: Wednesday, September 13