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November 15, 2018 – Dry with above normal temperatures through early next week except in areas of heavy smoke due to Camp Wildfire. Breezy northeast winds over the Sierra Nevada Saturday night into Sunday elevating fire danger. Cooler temperatures next week with a chance of precipitation interior NorCal mid week.

Discussion

Strong high pressure over the eastern Pacific and west coat will bring dry conditions with above normal temperatures through the short term period. Exception to above normal temperatures will be in areas of heavy smoke from the camp fire roughly from Chico to Sacramento. Insolation from smoke in these valley locations will keep daytime highs over the next couple of days close to normal for this time if year. Other impact of this wildfire smoke will be decreased visibilities throughout the central valley impacting aviation. Worst area of visibility currently is Oroville region where visibility is reported at 1/2 mile. Smokey valley conditions are likely to continue Friday and possibiy even Saturday as atmosphere remains stable and winds remain relatively light.

Models in fairly good agreement in dropping a shortwave trough southeastward through the Pacific Northwest on Saturday with high pressure rebounding over the west coast by Saturday night. Combination of light northeast to east flow aloft and a moderately tight northeast surface gradient across the Sierra will bring breezy northeast winds Saturday night especially to the higher elevations and favorably oriented Sierra and foothill canyons. These breezy winds which could bring elevated fire danger will be short lived with winds decreasing by Sunday afternoon. The brief wind event may be sufficient enough to mix some of the smoke out of the valley on Sunday so this region may see a little more sun during the second half of the weekend.

Extended Discussion (Monday through Thursday)

Upper high forecast to progress into the Great Basin Monday as trapped closed low to the south approaches CA. Progs weaken low as it moves inland across SoCal Tuesday. Medium models diverge significantly beyond Tuesday. EC brings stronger short wave trough into NorCal Wednesday with ridging returning Thursday, while GFS maintains upper ridging through Thursday. GEFS and NAEFSs showing upper troughing similar to EC, but slower progression with wave moving inland Thursday. Consensus points to some precip possible towards the latter part of next week, but low confidence in timing and amounts at the moment.