Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
198 FXUS66 KSTO 051938 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1238 PM PDT Sun May 5 2024 .SYNOPSIS... Cool, dry conditions will prevail this afternoon in the wake of Saturday`s late-season storm. Drier, warmer conditions return this week with gusty north to east winds mid-week. Valley highs will approach and possibly exceed the 90 deg F mark as early as Friday. && .DISCUSSION... Yesterday`s late-season storm has pushed inland over the last 12 hours, leaving in its wake dry conditions, plentiful sunshine, and a cool airmass for interior northern California. While GOES-West visible satellite imagery does reveal a patchwork of cumulus clouds bubbling up across much of the Golden State, think the chances of precipitation materializing from these clouds are slim (less than 5% chance). High temperatures this afternoon will peak in the low/mid-60s throughout the Sacramento and northern San Joaquin Valleys, equating to roughly 10 to 15 deg F below early May climatology. The synoptic pattern depicts the anomalously cold-core upper-level low over the Great Basin this afternoon, and is progged to dig south and east over the coming days. In this low`s wake, dry northwest flow will prevail over northern California as an upper- level ridge gradually amplifies through much of the week. By mid- week, a shortwave will drop from the Pacific Northwest and into the Great Basin, resulting in a period of offshore/northerly surface winds for the region. National Blend of Models advertises a 55 to 85 percent probability of gusts exceeding 40 mph across the north wind-prone areas of the western Sacramento Valley and northern Sierra foothills around Butte County. While the northerly flow will occur during the Tuesday-Thursday timeframe, current thinking is that the strongest winds will occur on Wednesday. In addition to the gusty winds, day-to-day warming will commence with Valley highs returning the upper-70s/low-80s by Wednesday. Even further warming is expected in the extended (see below). // Rowe && .EXTENDED DISCUSSION (Thursday THROUGH Sunday)... Upper-level ridge over the eastern Pacific will be northern California`s primary weather driver for the second half of the week. Cluster analysis of the ensembles depict solid agreement in the development of a broad, high-amplitude ridge over western North America. As a result, the early week warming trend will continue into the end of the week with Valley highs potentially eclipsing the 90-degree threshold as early as Friday. Communities such as Redding, Chico, Yuba City, and Sacramento all have a 50-60% chance of hitting 90 deg F on Friday, with similar probabilities for Saturday. // Rowe && .AVIATION... Northern Sierra, areas of MVFR in the vicinity of lingering showers thru 00Z Monday. Otherwise, VFR conditions will dominate, including all the Central Valley TAF sites. Local south to west surface wind gusts 15-20 kts this afternoon-early evening, otherwise winds will be generally less than 12 kts. Lighter south to west winds Monday before winds become more northerly Monday night. Gusty north to east winds Tuesday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$