Issued at 319 AM PDT Fri Oct 4 2024
Very warm and dry weather continues through the weekend. All heat-related hazards have been extended through Saturday evening. Temps drop a few degrees today before spiking again tomorrow. Light at the end of the tunnel starting to show early next week.
, (Today and Saturday) Issued at 319 AM PDT Fri Oct 4 2024
Although it's a relatively quiet night, quite a bit to look at meteorologically. First and foremost are the thermal belts and the impressive nocturnal drying that occurred this morning. As of writing, there are several sites above 1200' reporting temps in the low- to-mid 80s and RH as low as 1-5%. Some of these sites are reporting dewpoints that are rarely seen outside of a continental polar airmass. Thankfully there is very little wind, if any, across most of these sites. The exceptions being some of the highest peaks in the North Bay, such as Atlas Peak and Mt. St. Helena, which are seeing winds up to 20 mph. Given the winds are isolated to just a few sites, have held off from issuing a Red Flag Warning this morning. This nocturnal drying event has mainly taken place in the North Bay, and to some extent in the high terrain around the Bay Area. Dewpoints have started to recover and continue to trend upwards. This trend will be monitored throughout the morning to assess the need to escalate fire weather messaging (more in the FIRE WEATHER section below). If you were watching radar this morning, you also may have noticed some weak returns off the Central Coast moving to the NE. These are actually some elevated showers associated with some leftover tropical moisture at about 10,000'. The sad news is that there is an near zero chance of any liquid making it to the ground, since any rain that is falling would have to fall through a very deep layer of 4-10% RH and would certainly evaporate. The good news is that we are not expecting any lightning activity.
In terms of the ongoing heat wave, the above normal temperatures continue today, but we'll shave a few degrees off of what we saw yesterday. Temps will spike again Saturday as we see another weak push of offshore winds during the morning hours. As such, the Excessive Heat Warning and Heat Advisories that are currently in effect have been extended to Saturday night.
..(Sunday through Thursday) Issued at 319 AM PDT Fri Oct 4 2024
Going into the end of the weekend we should start to see some gradual relief as the ridge axis migrates eastward. The relief will be rather slow, however, and some areas may hold on to impactful heat into Monday, especially inland and southward along the Central Coast. There does appear some reasonable confidence in the pattern finally breaking down with a longwave trough moving in from the northwest by Tuesday. Ensemble guidance has also consistently advertised something we would all welcome this time of year as this trough digs into the West Coast by the end of the week. The signal is rather weak as of this issuance, but it has been there through the last few days of model guidance with consistent timing, so I'm inclined to take it at least a little bit seriously. I don't want to jinx us, so I'll just say the word starts with "R" and rhymes with "brain".
(12z TAFS) Issued at 1117 PM PDT Thu Oct 3 2024
VFR through the TAF period for all of the TAF sites. Dry conditions will limit cloud cover for all but the most immediate coast. Expect light and variable winds through the morning with more moderate winds expected into the afternoon, but becoming light again into the mid evening and early night.
Vicinity of SFO, VFR through the TAF period. Winds stay light through the morning before increasing to around 12 kts in the mid afternoon before becoming light again Friday night.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR through the TAF period. Expect light and variable winds through the early morning but winds become moderate in the late morning. Winds become light again Friday night.
(today through Wednesday) Issued at 544 AM PDT Fri Oct 4 2024
Dry thunderstorm activity is being observed in the southern waters with lighting possible into the mid morning. Light winds are expected through the weekend. More moderate winds arrive into the next work week with seas beginning to become more elevated.
Ca, Heat Advisory until 11 PM PDT Saturday for CAZ006-506-509- 528>530.
Excessive Heat Warning until 11 PM PDT Saturday for CAZ502>504- 508-510-512>518.
PZ, None.
