August-November Weather Summary

by
Gary Sanger
Climate Services Focal Point


August

August logoT he month of August was slightly warmer than normal. It was also dry in the central and southern San Joaquin Valley, except for one day when rain fell.

For the Southern Sierra Nevada, the Tehachapi Mountains, and the Kern county deserts, August began with monsoonal moisture and summer thunderstorms. A few of these storms brought heavy rain and some flooding in the Kern County Mountains.

The moisture continued to surge over the mountains on the 2nd with strong thunderstorms extending as far north as Lake Wishon in the Sierra Nevada. Some storms even approached severe levels near Grant Grove late in the afternoon. An upper-level disturbance moving through northern California pushed the monsoonal moisture east of the central California interior during the first full week of the month. This system also deepened the marine layer along the coast, with marine air spilling through the Sacramento delta and into the San Joaquin Valley. Due to the flow of cooler air, the high temperature in Fresno on August 5th was only 88 degrees. This was one of only two days on which the high was not at least in the 90s. For Bakersfield it was even cooler, with a high of 87 degrees. Pooling of marine air at the south end of the San Joaquin Valley also kept Bakersfield's high temperatures below 90 degrees for two more days.

High pressure began building over California and the desert southwest toward the middle of the month, with Fresno hitting 100 degrees on the 14th, for the first triple-digit day of August. Bakersfield would have to wait two more days before it saw the return of triple-digit heat.

Late August saw the return of subtropical moisture to the mountains and deserts of central California. Thunderstorms redeveloped over the high country of the Southern Sierra Nevada on August 20th, spreading down the range to the Piute and Caliente regions in Kern County where flooding was reported. A few of these thunderstorms drifted into the east side of the San Joaquin Valley, and one thunderstorm reached severe levels with outflow winds causing damage near Lindsay.

Afternoon and evening thunderstorms continued over the mountains on the 21st, before a southwest flow aloft pushed the storms mostly north of the region for a few days.

An upper- level disturbance moved over central California on the 25th triggering more thunderstorms, some of which continued through the night. Moisture from these thunderstorms drifted over the San Joaquin Valley on the 26th, where an unseasonably warm airmass triggered thunderstorms that brought the only rain of the month to Bakersfield and Fresno. Both cities recorded identical rainfalls of 0.04 inch; which also proved to be the first measurable rains either city had recorded on August 26th.



September

September logoS eptember continued the pattern of a mostly dry San Joaquin Valley floor, while episodes of convection continued over the mountains and deserts. No rain fell at Meadows Field through the month, while Fresno faired only slightly better as a few thunderstorms over the central San Joaquin Valley brought trace amounts of rain to the Fresno Yosemite Airport.

Several strong thunderstorms developed over the Southern Sierra Nevada on September 2nd, and a severe thunderstorm formed over the Mojave Desert near Edwards Air Force Base bringing wind damage to Rosamond. The next day was even more active, with heavy rains causing street flooding in the Kern County portion of the Sierra Nevada, and rock slides in the Tulare county mountains near the Kern/Tulare County line. Hail damage was also reported in the town of Lake Isabella.

Less organized mountain convection developed on the 4th, before drier air moved into central California and decreased the thunderstorm threat.

Marine air spilled into the San Joaquin Valley during the start of the second week of September, cooling afternoon highs into the mid 80s. High pressure returned to the region with a vengeance on the 11th, with high temperatures at both Bakersfield and Fresno rising 10 degrees from the day before.

A week later, another surge of marine air briefly cooled highs back into the 80s, but this was followed by a warming spell that brought the last 100-degree days of the year. The mercury climbed over 100 degrees on September 21st, for the start of three days of temperatures over the century mark. Bakersfield saw record heat on the 21st and 22nd, breaking the record high the first day and tying the record on the next day. The high temperature (and last 100-degree reading) at Bakersfield was 104 degrees on September 23rd, with Fresno reaching 101 degrees. The next day, marine air again pushed into the San Joaquin Valley, bringing 8-10 degrees of cooling.

Temperatures continued to cool slowly through the end of the month, with temperatures during the last two days of September in the mid 80s to around 90 at both Bakersfield and Fresno.



October

October logoF or the first four weeks of October, there was no significant weather across the central California interior. This changed abruptly during the last few days of the month as the first winter storm of the season ended the tranquil weather pattern.

Fresno and Bakersfield saw not only the last 90-degree days of the year in October, but also the last 80-degree days. In fact, Bakersfield actually had its last 90-degree day several days after its last 80-degree day.

The last 90-degree day in Fresno occurred on October 22nd, with the last 80-degree day coming on October 29th when the mercury climbed to 86 degrees. At Meadows Field, the thermometer last topped out in the 80s on October 25th when the high reached 88 degrees. This was followed by four days with temperatures in the lower 90s, which ended with a high of 90 degrees on October 29th.

Record highs were set at both Fresno and Bakersfield on the 27th and 28th, while Bakersfield's last 90-degree day tied the record high for the 29th. The winter storm that struck the central California interior at the end of the month brought a very cold airmass to the region. The high temperatures at Fresno and Bakersfield on October 30th were 65 degrees, with Meadows Field 25 degrees cooler than the day before.

Neither Fresno nor Bakersfield had any rain for the first 30 days of October, with Bakersfield undergoing a 65-day dry spell from its last measurable rain on August 26th. Fresno had trace amounts of rain on September 2nd and 3rd, but no measurable rain fell at Fresno Yosemite Airport from August 26th through the end of October.

The arrival of a winter storm was heralded by gusty winds that developed along the west side of the San Joaquin Valley during the afternoon of the 29th. Gusty winds also developed over the Kern County deserts, with several gusts between 40 and 50 mph. Rain and snow began spreading into the Southern Sierra Nevada on the 30th, then over the Tehachapi Mountains and the central and southern San Joaquin Valley on Halloween. Although Fresno did not see measurable rain on the 31st, Bakersfield registered a record 0.20 inch, which is 2/3 of the normal rainfall for the entire month at Meadows Field (0.30 inch).

Snow fell as low as 5000 feet in the Tehachapi Mountains, with Frazier Park seeing 2 inches of snow. Higher snowfall accumulations were seen in the Southern Sierra Nevada, with 4 inches of snow falling at Lodgepole, and up to 6 inches at Tuolumne Meadows in Yosemite National Park.



November

June logoT he storm that struck the central California interior at the end of October was the first in a series of Pacific storms that brought precipitation to the region during the first half of the month. A storm in the early morning hours of November 3rd brought heavy snow to the Yosemite area, with over 6 inches on the floor of Yosemite Valley, and 10 inches of new snow at Tuolumne Meadows.

Cold air with this storm filled the San Joaquin Valley bringing not only Fresno's first measurable rain in 68 days (0.07 inch), but also the first frost of the season for the central and southern San Joaquin Valley, which occurred on the morning of November 4th as the coldest Valley locations dropped into the lower 30s.

The next winter storm hit the central California interior on November 8th and 9th bringing 12-18 inches of new snow to higher elevations of the Southern Sierra Nevada. The storm also brought a quarter inch of rain to Fresno, with half that amount falling on Bakersfield. One very heavy shower dropped 2 inches of rain on the west side of Mendota in an hour, causing some local flooding.

The third storm of November hit the region on the 12th, bringing another 7 to 8 inches of new snow to the high country of the Southern Sierra Nevada. There was a brief respite in intensity before the fourth major storm of the month arrived on the 15th. This final storm brought the last precipitation to fall at either Fresno or Bakersfield during November, while adding another 5 to 7 inches of fresh snow to the Southern Sierra Nevada snow pack.

With the return of measurable rain to the central and southern San Joaquin Valley, there was an abundant supply of surface moisture to saturate the lower levels of the airmass over the region. As a result, the first widespread Valley fog event was observed on the morning of November 16th.

A dry storm system reached the central California interior on November 21st bringing strong winds to the Kern County deserts, and a very cold airmass to the San Joaquin Valley. Central and south Valley lows fell as low as 28 on the morning of the 22nd. The next day Fresno saw its first freezing temperature of the season (31 degrees), with the coldest Valley locations dropping to 25 degrees. The unseasonably cold temperatures continued through the morning of November 27th, before high clouds moved into California and inhibited the strong night-time cooling.






Selected August-November Spotter Reports

  NAME LOCATION REPORT
August 1st Frank Springer Tehachapi 0.84 inch in 30 minutes.
August 2nd Robert Keller Fish Camp Thunderstorm. 0.50 inch of rain in 30 minutes.
Richard Hudson Auberry 1.50 inch of rain.
August 20th Steve Johnson Highway 99 south of Tulare Blowing dust reducing visibility less than 1/4 mile.
August 22nd Terri Middlemiss Indian Wells Valley Funnel cloud over El Paso Mountains on 21st.
August 26th Jim Scofield Southwest Visalia Thunderstorm.
Sherry Buck Coalinga Thunderstorm.
September 2nd Cathy Moreno Rosamond Strong wind tore flagpole off house; blowing dust.
Eleanor Heiskell Glennville Thunderstorm. Gusts of 30 to 40 mph.
September 3rd Peter Stockton Granite Station Thunderstorm to east over Kern River.
Miles Muzio Lake Isabella 1.50 inch rain in 20 minutes; street flooding.
October 31st John Hibler Lush Meadow Snow pellets falling at 3300 feet.
Linda Curtis Frazier Park 1 inch of new snow.
November 1st Duane Johnson Hume Lake 1 inch of new snow.
Virginia Burrows Mountain Mesa 0.15 inch of rain.
November 4th Elizabeth Specht Lush Meadow 2.75 inches of new snow.
Bill Wootton Bear Valley Springs 0.5 inch of new snow.
November 9th Sarah Corum Visalia 0.27 inch of rain.
Rita Peterson Ponderosa Basin 1.22 inch of rain.
November 12th Jerry Brooks Ridgecrest 0.05 inch in one hour.



Climatological Records for
August through November 2003

Bakersfield
August 26th Record rainfall of 0.04 inch. The old record was a trace, set in 1999.
August 27th Record high minimum temperature of 75 degrees. The old record was 74 degrees, set in 1972.
September 3rd Tied the record high minimum temperature of 77 degrees, last set in 1976.
September 21st Record high temperature of 105 degrees. The old record was 104 degrees, set in 1928.
September 22nd Tied the record high temperature of 105 degrees, last set in 1928.
October 18th Record high temperature of 95 degrees. The old record was 94 degrees, set in 1988.
October 21st Tied the record high temperature of 94 degrees, last set in 1964.
October 27th Record high temperature of 91 degrees. The old record was 90 degrees, set in 1944.
October 28th Record high temperature of 92 degrees. The old record was 90 degrees, set in 1968.
October 29th Tied the record high temperature of 90 degrees, last set in 1930.
Tied the record high minimum temperature of 60 degrees, last set in 1992.
October 31st Record rainfall of 0.20 inch. The old record was 0.06 inch, set in 1933.
November 1st Record low maximum temperature of 58 degrees. The old record was 60 degrees, set in 1956.
November 12th Tied the record high minimum temperature of 54 degrees, last set in 1976.
Fresno
August 26th Record rainfall of 0.04 inch. The old record was a trace, last set in 1919.
September 3rd Tied the record high minimum temperature of 77 degrees, last set in 1998.
October 21st Record high temperature of 93 degrees. The old record was 91 degrees, set in 1991.
October 26th Tied the record high temperature of 89 degrees, last set in 1938.
October 27th Record high temperature of 89 degrees. The old record was 88 degrees, set in 1914.
October 28th Record high temperature of 89 degrees. The old record was 87 degrees, set in 1968.



Runnin' the Numbers

  FRESNO   BAKERSFIELD
Temperatures (oF) AUG SEP OCT NOV   AUG SEP OCT NOV
Average Maximum 96.3 94.5 84.6 62.5   95.3 95.1 85.6 64.4
Average Monthly 81.4 79.2 69.8 52.2   82.1 81.2 72.5 54.5
Departure From Normal +1.5 +4.6 +4.8 -0.5   +0.2 +4.5 +5.3 -0.3
Average Minimum 66.5 63.9 55.0 41.8   68.9 67.2 59.3 44.5
Maximum 102 105 93 73   102 105 95 75
Date(s) 25th, 26th 2nd 18th, 21st 7th   20th 2nd, 3rd, 21st, 22nd 18th 7th
Minimum 61 58 44 31   63 61 45 33
Date(s) 29th 18th 31st 25th   5th, 7th, 8th 9th, 17th 31st 23rd
Number of Days Max >90 29 24 5 0   27 23 8 0
Number of Days Min <32 0 0 0 2   0 0 0 0
Precipitation (in.) AUG SEP OCT NOV   AUG SEP OCT NOV
Total 0.04 Trace Trace 0.40   0.04 0.05 0.20 0.32
Departure From Normal +0.03 -0.26 -0.65 -0.70   -0.04 -0.10 -0.10 -0.27
Greatest in 24 Hours 0.04 Trace Trace 0.24   0.04 0.05 0.20 0.16
Dates 26th 2nd, 3rd 31st 8th   26th 2nd 31st 15th
Number of Days w/Precip. 1 2 1 9   1 2 1 7
Seasonal Total 0.04 0.04 0.04 0.44   0.04 0.09 0.29 0.61
Departure From Normal +0.02 -0.24 -0.89 -1.59   -0.04 -0.14 -0.24 -0.51
Compared to Normal 200% 14% 4% 22%   50% 39% 55% 55%
Wind (mph) AUG SEP OCT NOV   AUG SEP OCT NOV
Peak Speed 21 33 25 24   21 24 28 31
Direction NW S NW NW   NW SE NW SE
Date(s) 21st 2nd 29th 21st   20th, 21st 2nd 31st 27th
Pressure (in.Hg) AUG SEP OCT NOV   AUG SEP OCT NOV
Highest 30.05 30.05 30.24 30.37   30.05 30.03 30.23 30.35
Date 10th 11th 26th 27th   10th 11th 26th 27th
Lowest 29.71 29.69 29.59 29.93   29.73 29.66 29.59 29.92
Date 31st 22nd 29th 2nd   31st 22nd 29th 20th