Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
016 FXUS66 KHNX 160759 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1259 AM PDT Tue Jul 16 2024 .KEY MESSAGES... 1. The risk of grass fires across the San Joaquin Valley continues due to dry fuels, even with light winds. 2. Periodic afternoon thunderstorm activity over the Sierra Nevada is forecast to continue this week, with potential increasing this weekend. 3. High pressure builds back over the area in earnest early next week. There is a 60-80% chance of afternoon highs reaching or exceeding 105 degrees in the San Joaquin Valley next Monday. && .DISCUSSION... Afternoon highs continue to moderate across Central California as the ridge of high pressure that brought such extreme heat last week nudges eastward. Currently, its axis is over the Four Corners region. Therefore, afternoon highs are forecast to be just a degree or two above season norms for the next few days. Bouts of afternoon convection cannot be ruled out in the Sierra Nevada this afternoon due to marginal instability. Models are not as bullish on T`Storm activity on Wednesday, but do show a chance for convection Thursday afternoon. By Friday, NBM guidance gets a bit more bullish on afternoon highs trending back up. The aforementioned warming trend is due to the ridge axis shifting back to the west ever so slightly each day through early next week. This will lead to a warming trend over the weekend. Additionally, afternoon thunderstorms over the Sierra Nevada cannot be ruled out Saturday and Sunday afternoon, with chances extending into Monday afternoon as well. Afternoon highs and overnight lows will trend towards uncomfortable levels through late weekend, with the unfortunate return of Major Heat Risk by next Monday and Extreme Heat Risk by Tuesday. The ridge axis is projected to settle roughly over the Great Basin by next Monday, with its influence being strongly felt across Central California at the same time. NBM probabilities of afternoon highs reaching or exceeding 105*F by next Monday range from around 60% on the low end to 80% on the high end in the San Joaquin Valley. By Tuesday, these numbers jump to the 75-95% range, with some signals of 110*F afternoon highs occuring - a 30-40% chance as of this writing. If this forecast is to verify, the likelihood of a heat related headline for late weekend/early next week is quite high. && .AVIATION...Areas of MVFR and local mountain obscuring IFR in showers and thunderstorms over the Sierra Nevada 20z Mon through 01z Tue. Areas of MVFR and local IFR visibility will continue in and around wildfires. Otherwise, VFR conditions will prevail across the central CA interior until further notice. && .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. && $$ ab weather.gov/hanford