Possible Thunderstorms Today for Mariposa, Oakhurst and Yosemite National Park
May 19, 2020 - The National Weather Service reports a few strong thunderstorms are possible across Central California this Tuesday afternoon and evening.
Small hail, brief heavy rain and wind gusts near 45 miles per hour are some of the hazards associated with strong thunderstorms.
In addition to dangerous cloud to ground lightning strikes, any thunderstorm can produce localized flooding and possibly generate a funnel cloud.
Area Forecast Discussion National Weather Service Hanford CA 402 AM PDT Tue May 19 2020 .SYNOPSIS... A storm system will exit into the Great Basin today but continue to bring showers over the mountains into early this evening. There is a slight chance of mainly afternoon thunderstorms over much of the district today as well. Dry weather is expected tonight and during the next several days. Temperatures will remain much cooler than normal through Wednesday, then recover to seasonable levels Thursday and Friday. A major warming trend will begin this weekend and continue into early next week. High temperatures will be in the 90s in the San Joaquin Valley and desert by Sunday. && .DISCUSSION...Judging by water vapor imagery, the cold core low appears to currently be centered over the San Francisco Bay area. Radar shows numerous showers continuing over the mountains from Fresno County to Kern County. Mesonet data suggests that snow levels are generally above 7,000 feet but could be as lows as 6,000 feet in heavier showers. A few showers are still being detected on radar over the southernmost San Joaquin Valley at this time. Otherwise, the remainder of the central California interior is absent of showers and northwesterly winds have diminished considerably since Monday afternoon. The bulk of accumulating snow over the high Sierra is just about over, so will let the Winter Weather products expire at 5 am. Additional snow showers in the mountains today will bring at most a couple of inches in some locations above 7,000 feet. During the next several hours, the upper level low will drift eastward and should exit east of our CWA this afternoon. Although the upper atmosphere will begin to warm a bit by then, it will still be very cold aloft (-20C or colder at 500 mb), so as the mid May sun heats up the lower levels of the atmosphere, we`re likely to see isolated thunderstorms popping up again this afternoon. Otherwise, cloudy skies and showery weather will continue over the mountains into this evening. A prevailing northwesterly flow in the wake of this storm system will keep clouds banked up along the west slopes of the Sierra and the north facing slopes of the Tehachapi mountains tonight into Wednesday morning. The presence of a 100-knot jet over the CWA will support brisk northwest winds over the western half of the San Joaquin Valley Wednesday afternoon with gusts of up to 30 mph possible in a few locations along the I-5 corridor. Isolated afternoon showers could develop near the Sierra crest as well. Otherwise, dry weather should be the rule Wednesday with high temperatures remaining several degrees below normal. The models build an upper level ridge of high pressure into central California Wednesday night and Thursday. A weak upper level trough will flatten this ridge over central California Friday as the trough tracks eastward through the Pacific Northwest. Moisture and dynamics associated with this trough will be too far north to bring any more than some mid and high clouds to the central California interior later this week. However, the trough will stave our warming trend for a couple of days once high temperatures finally recover to seasonable levels Thursday. Sunday will mark the beginning of a major warm up over the CWA as a strong upper level ridge of high pressure builds over the Golden State. High temperatures of 90 degrees or higher can be expected in the San Joaquin Valley, lower foothills and the Kern County desert Sunday. Afternoon temperatures will be well into the 90s in these areas by Memorial Day. In the hottest locations, thermometer readings could top the century mark, especially one week from today. So enjoy this cool change in the weather. We may not see it again until late Autumn.Source: NWS
