June 24, 2019 – Daytime temperatures cooling through mid week with daytime highs Thursday well below normal. A warming trend begins at the end of the week with daytime highs climbing to above normal by next Sunday. No precipitation expected. Breezy winds through the delta, otherwise fairly light winds.
Discussion
Just a few high clouds over the CWA this morning under flat high pressure ridging. A moderate delta breeze may bring some coastal stratus into the delta this morning but Fort Org profiler shows the marine layer below about 1000 feet so a significant coastal intrusion is not expected.
Upper level high pressure ridge weakens and shifts eastward today as an unseasonably strong low pressure system drops out of the Gulf of Alaska and moves in off the Pacific Northwest coast. Daytime highs will drop a few to several degrees from Sunday highs but still come in a little above normal.
Still more cooling is expected on Tuesday as this upper low continues to dig southward off the Oregon and NorCal coast. Daytime highs Tuesday should come in a little below normal most areas. The cooling trend continues in to mid week as the upper low slowly pushes into the Pacific Northwest.
Daytime highs Wednesday and Thursday will fall to 10 or more degrees below normal as cooling airmass and onshore flow combine.
At this time, models keep any precipitation associated with the low to the north of the forecast area so for now, forecast through the short term period remains dry.
Extended Discussion (Friday through Monday)
A warming trend is likely through the forecast period as an upper level trough gradually weakens late this week and into the weekend. Highs are anticipated to be 5-15 degrees below normal through Saturday, followed by seasonal temperatures early next week. By early next week, look for Valley highs in the 90s, and 60s to low 80s over the mountains.