Area Forecast Discussion

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National Weather Service - San Joaquin Valley / Hanford, CA
Issued: Wednesday, November 20 2024 - 4:22 PM PST

UPDATE...Updated air quality issues.

KEY MESSAGES...

1. Temperatures will warm to around 5 to 10 degrees above climatological averages on Thursday and Friday.

2. A strong winter storm system is forecast to impact Central California Friday night through this weekend. Portions of the San Joaquin Valley and the Sierra Nevada Foothills may see moderate to heavy rainfall rates at times with moderate to heavy snowfall rates in the Sierra Nevada.

3. The probability of receiving one-half (0.5) inches of rain by 4 PM Saturday is 90% in Merced decreasing towards the south to 80% in Fresno, 50% in Visalia, and 20% in Bakersfield.

4. The snow level will be around 8,000 feet on Friday lowering near 7,000 feet around Yosemite NP by Saturday afternoon. The probability of receiving 12 inches of snow by 4 PM Saturday is 85% for Tuolumne Meadows and 90% for Tioga Pass.

DISCUSSION... Satellite loops show a solid overcast over northern California this afternoon with the southern edge of the cloud shield down to Madera County and sunny skies to the south. The abundant sunshine today compared to the extensive cloud cover yesterday along with a building ridge aloft has allowed temperatures to climb much higher than yesterday. The latest 24 hr trends show the San Joaquin Valley is 13 to 16 degrees warmer. The upper ridge will continue to build over the Rockies on Thursday and temperatures may nudge a little warmer. Expect little changes on Friday. Climatological average highs this time of the year are in the lower to middle 60s. Highs today through Friday are forecast to be around 5 to 10 degrees above average with lower 70s generally.

A strong winter storm system will begin to impact the central California interior on Friday evening. A deep upper low off the Pacific Northwest coast is steering an atmospheric river into northern California at this time. The AR is forecast to shift south on Friday night into central CA. Portions of the San Joaquin Valley and Sierra Nevada Foothills may see moderate to heavy rainfall at times with moderate to heavy snowfall in the Sierra Nevada. The probabilities for receiving one-half (0.5) inches of rain by 4 PM Saturday are 90 percent in Merced, 80 percent in Fresno, 50 percent in Visalia, and 20 percent in Bakersfield. The snow level will begin around 8000 feet Friday evening lowering to near 7000 feet around Yosemite NP Saturday afternoon. The probability for receiving 12 inches of snowfall by 4 PM Saturday is 85% for Tuolumne Meadows and 90% for Tioga Pass. Ensemble clusters continue to show uncertainty regarding the evolution of the upper low through the weekend into early next week. Given the unsettled pattern, precipitation chances remain 40 to 70 percent each day Sunday through Tuesday, with chances generally decreasing from north to south.

AVIATION... VFR conditions will prevail through the period at all terminals.

AIR QUALITY ISSUES... On Thursday November 21 2024, Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Fresno, Kern, Kings, Madera, and Tulare Counties. Burning Discouraged in Merced County, and Kern (Greater Frazier Park Area) and Sequoia National Park and Forest.

CERTAINTY...

The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium.

Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback.

HNX WATCHES/WARNINGS/ADVISORIES... None.