Yesterday was mostly sunny and mild. In the evening, the skies clouded up and it even looked like there was some rain (or at least virga) to the east of Socorro.
I have been on the road since 10 pm yesterday evening. We’ve only deboarded the van once so far, in Flagstaff, AZ, around 3:35 this morning. It was cool, still and partly cloudy. We are en route to San Francisco, so that is my forecasting target for the next several days.
The National Weather Service (NWS) in San Francisco forecasts a partly sunny day today, with a high temperature of 68 F. The winds will be from the west-southwest at 6-10 mph. This evening will be mostly cloudy, with a low temperature of 56 F. Winds will be from the west-southwest at 5-8 mph.
The visible satellite imagery and the enhanced infrared satellite imagery show no clouds over the state this morning. These images have been excluded from today’s post.
The water vapor imagery shows deep moisture over much of the state today. There is a low pressure system over the open waters of the Pacific, but it not having a direct impact with California at this time.
The 12Z upper air sounding is unavailable at this time.
The surface observations (from the SPC Mesoscale Analysis Map) show cool temperatures, moderate humidity (as shown by moderate dewpoint depressions), light winds, and clear skies across the state so far this morning. There are no major frontal boundaries over the state, though there is potentially a very complicated dryline in place.
The surface pressure map shows that there are no strong pressure systems or gradients over the state so far this morning. The RAP shows that none are expected to develop over the next six hours.
Synoptically speaking, the 300 mb NAM chart (from Unisys) shows some weak southwesterly flow as a small, upper-level trough digs south just off the California coast.
The 500 mb NAM chart shows no strong vorticity advection over the state today. This chart has been excluded from today’s post.
The 700 mb NAM chart shows no rapidly rising air over the state today. This chart has been excluded from today’s post.
The 850 mb NAM chart shows the beginning of some Cold Air Advection (CAA) pushes in from the northwest. The CAA will mostly remain offshore, but could be a factor in the weather tomorrow and Sunday.
The Precipitation chart shows that there is little chance of precipitation today, statewide. This chart has been excluded from today’s post.
Overall, today will be a mild and still day over the Bay Area. The NWS has a forecast for clouds, and I think that, between the high moisture content shown on the water vapor imagery and the slight CAA, clouds are quite possible by ths evening.
Thank you for reading my forecast.
The upper air soundings and mesoscale analysis plots are from the Storm Prediction Center website.
The forecasted upper air soundings are from TwisterData.com.
The surface observation and upper level charts are from Unisys Weather.
The satellite data is from NASA – MSFC