Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
815 FXUS66 KSTO 291929 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1229 PM PDT Mon Apr 29 2024 .Synopsis... Mild and dry weather this week. Occasionally breezy. Light precipitation chances return this weekend. && Dry and mild weather will persist through the week as several short-wave troughs pass to the north over broad ridging covering the eastern Pacific and NorCal. Precipitation chances will remain well to the north of the region across the PacNW, though occasional bouts of north to east wind are expected as surface pressure gradient tightens in the wake of each of these waves. The strongest period of northerly winds are expected Tuesday night and Wednesday with gusts of 35-45 mph possible in the Sacramento Valley and surrounding terrain with the strongest winds forecast to occur to the northwest of Sacramento along the west side of the valley (NBM probabilities are around 60-80 percent for reaching that range for wind gusts). Difficult driving conditions can be expected and loose objects may blow around. Valley high temperatures will be in the mid 70s to lower 80s. && .EXTENDED DISCUSSION (Friday THROUGH Monday)... Some disagreement remains with respect to the exact evolution of a passing upper level trough, but ensembles are coming into agreement on a shift to cooler and wetter weather next weekend into the following week. Prior to this though, mild and dry weather looks to hold on through Friday as a leading shortwave ridge ahead of the trough briefly centers over interior NorCal. This will likely result in the warmest high temperatures of the week, with low to mid 80s in the Valley and 60s to 70s across the higher terrain. As the aforementioned trough moves through or in proximity to interior NorCal, a period of more active weather will be possible next weekend into the following week. Current cluster analysis indicates a 40% chance of a deeper trough on a further southward trajectory moving through NorCal and a 60% chance of a weaker trough on a more northerly trajectory through the Pacific Northwest. That being said, there has been a trend within latest ensemble guidance toward the former scenario in the trough evolution. The former scenario would provide more weather impacts of increasing precipitation chances, breezy to gusty winds, and possible high elevation mountain snow, with the latter scenario providing more limited impacts of showery activity primarily confined to the northern Sacramento Valley and adjacent terrain. As a result, there is a fairly broad range of appreciable weather impacts at this time. Regardless of the exact track though, a cooling trend toward near to slightly below normal temperatures is anticipated through the weekend into early next week. && .AVIATION... Clear skies and VFR conditions expected across interior NorCal over the next 24 hours. Northwest winds in the Valley with sustained surface winds 10-15 kts with gusts 20-25 kts through 00Z Tuesday. Over the mountains, wind gusts up to 30 kts through 02Z Tuesday. Surface winds decrease to below 12 kts (00Z to 12Z Tuesday) before northerly winds increase to 10-15 kts with gusts 20-25 kts after 14Z Tuesday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$