Area Forecast Discussion

SYNOPSIS

Dry weather is expected today and Friday with chilly overnight temperatures and sunny afternoons. A few rain showers and interior thunderstorms are possible starting Friday through early next week.

DISCUSSION

High pressure continues to build over the area, with skies slowly starting to clear. Abundant moisture from recent rains and high dew points may bring fog to many interior valleys this morning. Valleys that remain cloud-free could drop into the low to mid 30s, bringing the possibility for frost this morning. High temperatures will rebound today as skies clear, with 70s likely for much of the interior. Breezy north winds in the afternoon at the coast will likely keep temperatures in the mid to high 50s. Low temperatures tonight will broadly be in the mid 30s to low 40s. Frost may be possible in the coldest interior valleys again, and additional Frost Advisories may be needed.

Friday into the weekend, an upper-level low approaches the Central California Coast while a trough digs into the northern Rockies. Moisture from the upper low may reach just far enough north to bring a few showers or an isolated thunderstorm to the interior Friday, though much of this activity may end up south and east of the area. Chances are better Saturday when there is additional moisture and higher instability. The troughing pattern continues Sunday into early next week. Afternoon showers and isolated thunderstorms, if all the ingredients line up, are possible each afternoon into early next week. Total rain amounts are meager, with only around a 20-40% chance for wetting rain (0.1" or more) over a 72-hour period from Saturday morning to Tuesday morning. The highest chances are in Trinity County. Chances for over an inch of rain are only around 10- 20% in interior Del Norte and Humboldt and over portions of Trinity County. Ensemble clusters are showing high confidence in a ridging pattern and drier weather returning by mid next week. JB

AVIATION

Clouds have gradually cleared over the past 24 hours, but instability and winds have generally prevented any marine layer formation. There is a remoter chance (10%) of isolated IFR ceilings around sunrise, but otherwise VFR will persist through the day Thursday. There is a slight chance (25%) of a MVFR to IFR marine layer forming up Thursday night into Friday. /JHW

MARINE

Currently moderate northerly winds will begin to increase through the day Thursday, especially in the southern waters with gusts over 25 kts in the lee of Cape Mendocino by later this evening. Short period seas will quickly build over 8 feet in response to the winds. Stronger breezes will briefly push closer to shore in the southern waters Thursday evening. Similar winds will most likely continue into the end of the week but are more likely to gradually shunt back out into the outer waters. A very minor southerly swell around 2 feet will slightly modify the sea state through the weekend. /JHW

EKA WATCHES / WARNINGS / ADVISORIES

CA... Frost Advisory until 8 AM PDT this morning for CAZ102>106- 109-110-112-113-118>120.

Freeze Warning until 8 AM PDT this morning for CAZ108-111- 114-117.

Freeze Warning until 9 AM PDT this morning for CAZ116.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 11 AM this morning to 9 PM PDT this evening for PZZ455.

Small Craft Advisory from 6 PM this evening to 9 AM PDT Friday for PZZ470.

Small Craft Advisory from 8 AM this morning to 3 PM PDT Friday for PZZ475.