June 14, 2019 - The National Weather Service Hanford Office reports isolated thunderstorms are possible along the Sierra Nevada crest today through Sunday.
Small hail and wind gusts near 40 miles per hour are a couple of hazards associated with strong thunderstorms.
In addition to dangerous cloud to ground lightning strikes, any thunderstorm can produce intense rainfall rates, leading to localized flooding.
Area Forecast Discussion National Weather Service Hanford CA 349 AM PDT Fri Jun 14 2019 .SYNOPSIS...Slightly cooler temperatures can be expected over the district through the weekend. Isolated afternoon thunderstorms are possible over the higher elevations of the Sierra each day through Monday. Otherwise dry weather will prevail through the period. Gusty winds will continue below the passes into tonight. && .DISCUSSION...High temperatures yesterday were a few degrees lower over much of the central California interior. In the San Joaquin Valley, it was the first day since Sunday that thermometer readings stayed below the century mark. Based on current 24-hour trends, high temperatures today should be even a few degrees lower than yesterday. The comfortable change in the weather should last through the weekend as a couple of weak short wave troughs move across the Golden State. The first of these upper level troughs will exit into the Great Basin this afternoon and be followed by weak ridging aloft tonight into Saturday. Another weak, upper level trough will move into the central California interior later this weekend. Although these systems are limited on moisture, they`ll pick up enough moisture from melting snow over the highest elevations of the Sierra to generate isolated afternoon thunderstorms near the crest each day through Father`s Day. Elsewhere over the CWA, skies will remain mostly clear through the weekend. The passage of each of these upper level troughs will maintain an onshore flow across central California, which in turn will keep diurnal temperatures in check over the CWA during the next few days. Daily highs will average near to slightly above normal for the middle of June while nightly low temperatures stay relatively cool. The onshore flow has strengthened a bit since yesterday morning, and it will continue to support gusty west winds through and below the mountain passes today into tonight. Winds have been gusting to about 30 mph through Pacheco Pass and Cottonwood Pass and have gusted as high as 55 mph below Tehachapi Pass and Walker Pass. Although winds abate somewhat in these areas this morning, they`ll likely ramp up again this afternoon and remain gusty into this evening. Another wind advisory seems warranted for the Kern county desert right below the passes during this time period so watch for a new one to be issued after the current one expires at 5 am this morning. Another benefit of these upper level troughs is that they keep a marine layer established along the coast. The marine layer off the central California coast is currently about 2,000 feet deep. Its depth has changed little during the past 24 hours but all it has to do is deepen by another 500 feet or so to make it through the coastal mountain passes and bring further cooling into the northern San Joaquin Valley. If so, high temperatures could remain below 90 degrees in parts of Merced county the next couple of days. The onshore flow will dwindle after the weekend and become offshore by Monday afternoon as the second upper level trough exits into the Great Basin. Northeasterly winds aloft could carry a few Sierra thunderstorms into the foothills by early Monday evening and even bring some debris clouds into the eastern part of the San Joaquin Valley. After Monday, hot weather is going to make its inevitable return to the lower elevations of the CWA as a strong Eastern Pacific ridge of high pressure builds into California. Triple digit heat will return to the San Joaquin Valley, lower foothills and the Kern county desert Tuesday and persist through next Friday, which, by the way, is the first day of Summer. Despite slightly cooler weather in the short term, there`s still plenty of snow to melt over the high Sierra. Although that melting process has slowed some, rivers will continue to run deep, swift and cold and will remain dangerous for anyone venturing into them. In fact, high flows will likely continue on the rivers well into July or at least until all of the snow has melted over the Sierra.Source: NWS
