Projected rainfall totals for Mariposa: 1.00" to 1.50"
Projected rainfall totals for Oakhurst: 0.50" to 1.00"
Projected rainfall totals for Yosemite Valley: 1.00" to 1.50"
December 2, 2019 - The National Weather Service Hanford Office reports a plume of enhanced atmospheric moisture will sit over the northern portion of the forecast area today and tonight.
A Winter Storm Warning is in effect for the Southern Sierra Nevada above 7,000 feet, where up to an additional two feet of snow is possible.
The majority of this precipitation will fall today.
Area Forecast Discussion National Weather Service Hanford CA 315 AM PST Mon Dec 2 2019 .SYNOPSIS... A plume of enhanced atmospheric moisture will sit over the northern portion of the forecast area today, resulting in periods of heavy rainfall below 7000 feet and abundant snowfall above 7000 feet. Precipitation amounts will gradually decrease through the end of today. Another storm system will begin to affect areas further south, such as Kern County areas, on Tuesday night through Wednesday night. && .DISCUSSION... Light to moderate rain continued throughout today across the Southern San Joaquin Valley as the advertised atmospheric river decided to setup shop from Fresno County northward into Northern California. 24 hour rainfall amounts ranged from less than 1/3 of an inch in Kings, Kern, and Tulare Counties. Amounts then increased to around 2/3 of an inch in Fresno County, up to one and a half inches in Merced County. As usual, orographical effects increased precipitation amounts in the Central Sierra foothills and Mountains, where many several locations received between 2 to 4 inches. In addition, very strong winds occurred in the Grapevine, with wind gusts up to 80 mph. As for our current synoptic setup, not much has changed over the last 24 hours. GOES 17 water vapor imagery continues to show deep, long fetch of subtropical moisture streaming into the Central California interior. This setup will continue through today, before ended later this evening. With the moist onshore flow and subsequent orographical precipitation enhancement, heavy rain and mountain snow will continue to impact the area. An additional 1-2 inches of rain is possible in the foothills, especially from Fresno County northward, as well as one to two feet of additional snow through early Tuesday Morning. As such, the Winter Storm Warning is continued through Tuesday Morning. Light Precipitation will continue across the northern CWA, where additional rainfall amounts of up 2/3 of an inch is possible through Tuesday Morning. The current upper level low now at 40N/130W will slowly start to move southward over the course of today into Tuesday. This low will move quickly through the area late Tuesday, and is out by Wednesday evening. At this time, model guidance gives precipitation totals from late Tuesday into Wednesday afternoon ranging from 1/4 to 1/2 of an inch in the valley, and up to one to 1.5 inches in the Sierra and Kern County mountains. Also, 1/3 to 2/3 of an inch possible in the Kern County desert. Heavy snowfall is expected into the Sierra, where winter weather products will have to be considered, or be likely. The biggest uncertainty with the precipitation totals is if this next upper level low moves faster through the area, reducing precipitation totals. After this shortwave trough exits the region, well have ridge transit the area on Thursday. For locations in the valley, with abundant surface moisture, calm winds, and high pressure aloft, fog will start to be an issue on Thursday morning. On Friday to the end of next weekend, a deep 530dm low pressure drop south from the Gulf of Alaska, before moving slowly eastward toward Oregon on Saturday. At this time, long-term models are showing precipitation beginning on late friday and extending into Sunday afternoon. Models then start to show a ridge setting up by the beginning next week with a return of dry weather.Source: NWS
