Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
524 FXUS66 KSTO 112044 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 144 PM PDT Tue Jun 11 2024 .SYNOPSIS... Hot temperatures through Wednesday with Moderate to Major HeatRisk. Temperatures will trend cooler late in the week and over the weekend. Isolated shower/thunderstorms over the Sierra Crest south of Highway 50 this afternoon and Thursday afternoon. Elevated fire weather conditions late weekend/early next week. && .DISCUSSION... Key Points - An Excessive Heat Warning for areas north of I-80 remains in effect through Wednesday evening with Major HeatRisk and widespread triple digit highs. - A Heat Advisory for areas south of I-80 remains in effect through Wednesday with widespread Moderate HeatRisk and areas of Major HeatRisk. - A cooling trend begins Thursday, with close to normal temperatures by the weekend - Gusty north winds and low relative humidities expected to cause elevated fire weather concerns in the Valley on Sunday & Monday - Local waterways are still running cold and fast from snowmelt Short-Term Discussion (Today THROUGH Friday)... Clear skies continue through the region this afternoon, though some limited areas of popcorn cumulus can be seen south of HWY 50 over the mountains. There is a 10-20% probability of isolated thunderstorms in these areas this afternoon and evening. Otherwise, hot and dry weather continues across interior NorCal today and Wednesday. Temperatures in areas of the Valley adjacent to the Delta Region look to be marginally cooler on Wednesday though, with onshore flow bringing more of an impact a little earlier than expected. Day time temperatures will still be quite hot though, especially further away from the Delta region. In the Sacramento metropolitan area, temperatures will generally fall somewhere in the 90s. Elsewhere, temperatures will range from the upper 90s to the mid 100s. Due to these temperatures, a Heat Advisory remains in effect until Wednesday evening for areas generally south of Yuba City, and an Excessive Heat Warning until Wednesday evening for areas generally north of Yuba City. A cooling trend begins Thursday however, bringing high and low temperatures back to more seasonable norms. Valley highs will range from the upper 80s to the high 90s as we head into the weekend. There are additional chances (10-20%) for isolated thunderstorms on Thursday afternoon and evening in the mountains south of HWY 50. Otherwise, dry and relatively calm weather continues as the area begins to cool. Though while the air is warm, local waterways are cold and fast due to snowmelt. Exercise caution around the water, and practice cold water safety! To view the latest HeatRisk, please visit www.wpc.ncep.noaa.gov/heatrisk/ To view current water temperatures, please visit www.cnrfc.noaa.gov && .EXTENDED DISCUSSION (Saturday THROUGH Tuesday)... Temperatures will remain near seasonable levels over the weekend and into early next week, with Valley highs reaching around the low 90s, and higher elevations seeing day time temperatures in the 70s and 80s. However, with the cooler weather, comes elevated fire weather concerns on Sunday and Monday. A low pressure system dropping down from the north and into the Great Basin will bring gusty north winds and relative humidities in the teens to the Valley, causing widespread elevated fire weather concerns in the Valley. There is still some uncertainty with this event, specifically with regards to how strong gusts will be and how low RH will get; however, there is currently a 25 to 60% probability of wind gusts over 40 mph between Redding and Woodland in the Valley, with highest chances along the I- 5 corridor. We will be continually monitoring these conditions as we get closer to the event, stay tuned for updates! //SP && .AVIATION... Generally VFR conditions over interior NorCal next 24 hrs except possible isolated MVFR in thunderstorms over higher terrain of Alpine and Tuolumne counties until 03z Wednesday. Surface wind mainly below 12 kts except vicinity of Delta after 00z Wed southwesterly wind gusts up to 20 kts possible. && .STO WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM PDT Wednesday for Central Sacramento Valley-Mountains Southwestern Shasta County to Western Colusa County-Northeast Foothills/Sacramento Valley- Northern Sacramento Valley-Shasta Lake Area / Northern Shasta County. Heat Advisory until 8 PM PDT Wednesday for Carquinez Strait and Delta-Motherlode-Northern San Joaquin Valley-Southern Sacramento Valley. && $$