Author: John Hibler

May 16, 2018 Summary:  Water vapor satellite imagery clearly depicts a closed low centered right over the San Francisco Bay Area this morning.  This system will inch its way across central California today into early Thursday then will move into the Great Basin by Thursday afternoon.  An absolute wall of marine air surged over the…

May 15, 2018 Summary:  Looking at visible satellite imagery at this hour we find the usual fog and low cloud deck along the coast, extending inland with only the last range of mountains separating the valley from that coastal air.  Satellite imagery also clearly depicts a finger of low clouds moving through the Delta then…

May 14, 2018 Summary:  Low pressure currently straddles the Nevada/Utah border.  Northern and central California remain under the circulation pattern of the counterclockwise flow around the low.  A mid level cloud deck based at 8,000 feet covers portions of the eastern and southern San Joaquin Valley, but poses no threat of precipitation.  The low has…

May 12, 2018 Summary:  Low pressure both at the surface and aloft is centered over the Great Basin this morning and will remain there through Monday, although by Monday it will be a weaker version.  The counterclockwise circulation around the low has winds aloft out of the northeast over northern and central California.  This is…

May 11, 2018 Summary:  Upper level low pressure is sliding southward from Idaho and will park over the Great Basin later this afternoon.  A new surface low is also developing over southern Utah.  This low is projected to pretty much remain in place through Monday but by Sunday and Monday it will slowly be weakening. …

May 10, 2018 Summary:  Temperatures are running 3 to 6 degrees below what they were 24 hours ago.  A trough of low pressure now moving into the Pacific Northwest has created a westerly flow over central California, both at the surface and aloft.  Marine air is moving inland.  I noted the winds at Pacheco Pass…

  May 9, 2018 Summary:  The main forecast challenge all the way through early next week will be temperature considerations.  There is a weak trough moving into the Pacific Northwest and western Canada this morning with the trailing portion of this system down into northern California.  This will add some synoptic cooling today, although I…

May 8, 2018 Summary:  Today will be the warmest we will see for a while.  Upper level high pressure is reaching its pinnacle.  Low to mid 90s are likely throughout the valley this afternoon.  There is a low pressure system approaching the coast of the Pacific Northwest.  This system will take an interesting path as…

May 7, 2018 Summary:  The weather system that moved through the Pacific Northwest and northern California has now moved eastward out of the region.  It did manage to lower temperatures a bit, which will carry over into today.  Strong upper level  high pressure over the eastern Pacific is upwelling ahead of a new low.  This…

May 5, 2018 Summary:  The only real difference today over yesterday will be a veil of high, thin clouds from a weather system currently approaching the coast of the Pacific Northwest.  The high clouds will probably not be thick enough to have an impact on temperatures this afternoon.  Readings will once again pass the 90…