Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
005 FXUS66 KHNX 012210 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 310 PM PDT Wed May 1 2024 .KEY MESSAGES... 1. Warming conditions are forecast through the end of the work week with highs around 3 to 7 degrees above normal on Friday. Probabilities of exceedance for 84 degrees in the San Joaquin Valley are around 50% to 70%. 2. Ensemble guidance is trending towards a weekend storm system bringing snowfall to the Sierra Nevada and periods of rainfall to the San Joaquin Valley. 3. High temperatures are forecast to cool to around 10 to 15 degrees below normal by Sunday. 4. Dry with a gradual warmup Monday through Wednesday && .DISCUSSION... We are experiencing another sunny, breezy and seasonably mild day across our area, beneath a broad trough residing over the western United States. High temperatures are on track to top out just a degree or so above normal this afternoon. Look for similar conditions through the end of the work week, with a slight warmup in advance of an approaching low pressure system dropping out of the northeast Pacific. High temperatures Friday afternoon will be around 3 to 7 degrees above climatological normal values. Probabilities for high temperatures of at least 84 degrees on Friday are around 40 percent in Merced County, and around 50 to 70 percent in the remainder of the San Joaquin Valley. The incoming low pressure system will impact central California by Saturday, bringing cooler temperatures and gusty winds, along with areas of rain and mountain snow. There are timing and trajectory differences amongst the model ensemble solutions, but the closed upper low is generally agreed to move into the Oregon coast Saturday and swing inland near the Great Basin Region by Sunday. High temperatures Saturday will be around 10 to 15 degrees cooler than on Friday in areas from Fresno County north, with just a few degrees of cooling down in the south end of the San Joaquin Valley. By Sunday, cooler temperatures will spread across our entire area, and probabilities that high temperatures will be no higher than 70 degrees in the San Joaquin Valley on Sunday afternoon are around 50 to 70 percent. Precipitation is forecast to begin spreading southward into central California by early Saturday morning and continue over the area into Saturday evening, with lingering Sierra showers through Sunday morning. QPF shows pretty good rain shadowing, with a few tenths of an inch of rain along the east side of the San Joaquin Valley and lower foothills, but just a few hundredths to around a tenth of an inch toward the west side and south end. About 3/4 inch of rain is progged in the higher terrain below the snow line, which starts above 8000 feet and lowers to around six to seven thousand feet by later Saturday and as low as four to five thousand feet Sunday morning. There is a good bit of uncertainty with Snowfall amounts we may receive from this system. The low end forecast(90% chance for at least this amount) shows no more than around 1 to 2 inches in the higher elevations of the Sierra north of Kings Canyon, while the high end forecast(10% chance for this amount or more) shows as much as 15 to 20 inches over much of the high Sierra north of Kern County. Stronger wind gusts will also accompany the passing system on Saturday, especially over the mountain ridges and in the typically wind prone areas of Kern County. Probabilities are around 40 to 60 percent for wind gusts of at least 50 mph in areas around the Mojave Desert Slopes on Saturday. Dry and gradually warming conditions return to our area for the first half of next week in a dry northwesterly flow. && .AVIATION... VFR conditions will prevail across central CA for at least the next 24 hours. && .AIR QUALITY ISSUES... None. && .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. && $$ public/aviation...JEB IDSS..............MM weather.gov/hanford