Today was a strange day weatherwise in the northern San Joaquin Valley. Not only did the area experience unseasonably warm temperatures and high humidity, but instability coupled with strong southwest winds aloft made for quite an interesting afternoon in the Modesto area.
Overcast skies overnight only allowed the temperature to drop to 57F in Turlock (10 mi ESE of Modesto), which is believed to be the warmest a minimum temperature has been so early in the year. The overcast began breaking up after sunrise, but temperatures did not rise all that much due to abundant moisture in the low levels of the atmosphere.
Fast forwarding ahead to the early afternoon hours, the ingredients for interesting weather became obvious around 2 pm. At this time, the air temperature varied between 68F and 70F while the dewpoint ranged from 60F to 62F. Towering cumulus were building up in all directions. Some of the cumulus towers to the west were showing signs of tilting in a northeasterly direction, which led me to believe there were strong southwest winds aloft.
While most cumulus clouds dissipated, the towers to the west maintained their shape and grew to cumulonimbus. The cell remained over the Diablo Range in western Stanislaus County for quite some time, but around 4 pm it began slowly moving northeast towards Modesto. Between 4 pm and 6 pm, reports of funnel clouds were fielded by TV stations and the National Weather Service as the cell moved through northern neighborhoods of Modesto and into the town of Oakdale. Following is a special weather statement issued by the National Weather Service in Sacramento.
WWUS35 KSAC 060035 SPSSAC CAZ005-060130- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SACRAMENTO CA 435 PM PST MON FEB 5 1996 ...FUNNEL CLOUDS REPORTED IN STANISLAUS COUNTY... AT 430 PM, A FUNNEL CLOUD WAS REPORTED BY SPOTTERS NORTH OF THE TOWN OF PATTERSON. RADAR INDICATED LITTLE MOVEMENT OF THESE STORMS. PEOPLE NEAR THE AREA SHOULD BE PREPARED TO TAKE COVER IF THREATENING WEATHER APPROACHES. ROWE
The thunderstorm moved parallel to Turlock, never coming much closer than 15 miles. There were a lot of low clouds SE of the cell which obscured the view of the cloud bases. None of the observers at area airports saw anything more interesting than the cumulonimbus clouds as well. Following are surface reports from airports in the area.
MOD SA 0147 16 SCT E200 BKN 10 65/59/1204/028 MOD SA 0047 16 SCT E200 BKN 20 66/59/1605/028 MOD SA 2352 E20 BKN 200 BKN 20 67/59/1405/026
Stockton Airport (20 mi NW of Modesto)
SCK SA 0147 40 SCT E200 BKN 10 65/59/0000/027 SCK SA 0057 200 -SCT 15 68/58/2807/026 CB NE-SE SCK SA 2350 25 SCT E50 BKN 15 68/58/2407/027
Merced Airport (40 mi SE of Modesto)
MCE SP 0131 18 SCT E30 BKN 150 BKN 20 63/60/0000/026 MCE SA 2354 18 SCT E30 BKN 150 BKN 20 65/59/1604/026
The cell moved into Calaveras County after sunset, where it dissipated. Additional cumulus clouds moved into the area during the evening, but by mid-evening virtually all precipitation had ended.
Later that evening....
Local news stations have been showing very interesting pictures of today's storm in Stanislaus County. KCRA-TV in Sacramento sent a reporter to north Modesto to cover the heavy flooding which occurred as a result of this afternoon's heavy rain. Even six hours after the downpour, many intersections on the north side of the city are still flooded.
In Patterson, a resident captured spectacular video of a large funnel cloud which appeared to come very close to touching the ground. There appeared to be a wall cloud above the funnel, which meant that this storm may have been a supercell. Most funnel clouds in the Central Valley are of the non-supercell, cold air funnel variety. Either way, it would have been something had the funnel cloud touched down. It has been eight years since the last tornado touchdown in Stanislaus County.
My stats for the day go as follows: Max temp 70F, Min temp 57F, Precip .03". My season precipitation total now stands at 8.35", well above the average of 6.60".