Projected rainfall totals for Mariposa: 1.00" to 1.50"
Projected rainfall totals for Oakhurst: 1.00" to 1.50"
Projected rainfall totals for Yosemite Valley: 1.50" to 2.00"
May 17, 2020 - The National Weather Service Hanford Office reports a storm system will impact Central California this evening through Tuesday afternoon.
Snow levels will start at around 9,000 feet Sunday evening.
Snow levels will gradually lower, reaching 6,500 feet by Tuesday.
The majority of this precipitation will fall Monday.
Area Forecast Discussion
National Weather Service Hanford CA
411 AM PDT Sun May 17 2020
.SYNOPSIS... Dry weather will continue through this afternoon, then a Pacific storm system will spread precipitation across the area from this evening through Tuesday. Periods of breezy to windy conditions are expected over the next several days, especially in the wind prone areas. Thunderstorms will be possible Monday and Tuesday. Near normal temperatures today will fall to well below normal Monday and Tuesday, but then trend warmer later in the week. && .DISCUSSION... The upper ridge that brought us warm and dry conditions yesterday has now shifted east with the axis over the Four Corners region. This puts us on the warm side of the ridge under a southwest flow aloft. So despite some cloud cover today, we should see similar temperatures to Saturday, with highs at to slightly above normal. But a Pacific storms system will begin to impact the district by this evening with much cooler and unsettled conditions continuing through Tuesday. A ~540 DM upper low is spinning off the Pacific Northwest coast this morning and there is a 1.3" PWAT moisture plume extending offshore from the SF Bay area. The upper low will slowly shift southeast today, driving a cold front down through California. Precipitation may begin as early as this afternoon around Yosemite NP, but will really ramp up tonight as the front moves in. The combination of the rich moisture plume and enhanced orographic lift in the southwest flow aloft, should result in some healthy precipitation amounts across the Sierra. The low is progged to be over the northern California coast on Monday afternoon. This will create a more unstable air mass and there could be some isolated afternoon thunderstorms north of Fresno County. By Tuesday, the low shifts over northwest Nevada which will extend the unstable conditions farther south. Thunderstorm chances look to mainly be over the Sierra on Tuesday. Precipitation amounts will be quite variable. Rain shadowing will limit rainfall on the west side of the Valley with some areas likely seeing only a few hundredths of an inch. The east side of the Valley could see a quarter to one half of an inch. The Sierra Nevada could see some significant totals; from around 1.5" in Yosemite NP to 1" in Kings Canyon NP. Lesser amounts are expected as you go south with only a tenth to one quarter of an inch in the Kern County Mountains. The Desert in Kern County may not see much rain at all due to shadowing effects. The snow level will start out around 10,000 feet tonight the lower to 7,000 feet on Monday. A Winter Storm Warning is in effect for the Sierra above 7,000 feet from Yosemite to Kings Canyon NP from 6 PM this evening until 4 PM Tuesday. Total accumulations of 6-12 inches are expected with isolated amounts up to 15 inches possible. A Winter Weather Advisory is in effect for the Sierra above 7,000 feet from Sequoia NP to the Tulare/Kern County line. Total snow accumulations up to 4 inches will be possible. A few showers may develop around Yosemite on Wednesday, but little impact expected. Periods of gusty winds will occur the next few days as well. Temperatures will go from near normal today to well below normal Monday and Tuesday. Forecast highs on those days are generally around 12-18 degrees below climatological normals. Temperatures rebound quickly this time of the year and we expect highs to be back near normal by Thursday. Another upper trough may brush the region on Friday and nudge temps back down a bit. An upper ridge is progged to build in next weekend for seasonable temperatures and dry weather.Source: NWS