FXUS66 KMFR 180944 AFDMFR

Area Forecast Discussion National Weather Service Medford OR 244 AM PDT Wed Sep 18 2024

DISCUSSION
A low is moving south along the northern California coast and will continue to shift southward today. Scattered showers are continuing overnight, with the best chances (40-60%)
of showers along and near the Cascades and into northern California as well as along the coast and into the Umpqua. Shower activity with diminish in the morning hours as the low shifts south. Models remain on track showing scattered showers across northern California this morning, becoming isolated in the afternoon. There is a slight chances (15%) for thunderstorms as well this afternoon in southern Modoc County and a low (10%)
chance for thunderstorms in southwest Siskiyou County. Otherwise, expect mild temperatures. Lingering moisture will result in areas of low clouds and valley fog tonight and Thursday morning, mainly along the coast from Cape Blanco north and into the Umpqua basin.

High pressure will build into the area tonight and Thursday then remain in place through late in the week. This will result in a warming trend with mild morning lows and warm (slightly above normal) afternoon highs. Breezy to gusty (north to northwest)
afternoon winds are expected Thursday and Friday. Tonight through Friday night, a thermal trough along the coast will also result in breezy northeast winds in the overnight hours for the coastal mountains and for the mountains in western Siskiyou. With this pattern, humidities will gradually trend drier but we are currently not expecting critical fire weather conditions.

On the weekend, expect high pressure to remain in place. A couple weak upper level disturbances will move over the ridge and into the area late Saturday and Sunday. Models favor continued dry weather with temperatures remaining above normal through the weekend. Then high pressure is forecast to strengthen and temperatures trend higher early next week. Mid week, ensembles are indicating an upper level trough and weak front may move into the region (around Tuesday night into Wednesday). This is expected to bring a slight chance (10-20%) for showers to far northwest portions of the area and allow for temperatures to trend less warm.
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