textproduct: Eureka

KEY MESSAGES

- Rain will be coming to an end early this morning with dry and slightly below normal temperatures Tuesday.

- Temperatures will warm quickly with minor to moderate HeatRisk expected Thursday through the weekend

- Elevated fire weather conditions in Lake County with low afternoon relative humidity and gusty winds Wednesday through Thursday.

SYNOPSIS

Clearing skies and temperatures below seasonal normals are expected Tuesday. Temperatures are expected to warm to the upper 90s to around 100 late week into the weekend with a moderate heat risk.

DISCUSSION

Rain will come and end early this morning as a storm system moves out of the area. High pressure and northerly winds start to build back into the area on Tuesday. The low clouds in the valleys may take some time to clear out, although most areas are expected to see clear skies by midday. Highs are expected to warm into the 70s in most of the inland areas although Lake county may be close to 80. Tuesday night into Wednesday morning is expected to be a chilly night with most areas falling into the 40s. Frost is possible in the coldest spots in Trinity and eastern Humboldt counties, such as Ruth, Hayfork and Valley.

High pressure builds in on Wednesday with inland highs warming around 10 degrees over the previous day yielding highs in the upper 80s to low 90s. Thursday the temperatures are expected to increase by another 10 degrees or so with highs climbing into the upper 90s to around 100 in many of the inland valleys. At the coast offshore flow each night is generally expected to keep coastal areas clear with the ridge axis to the west of the coast. Breezy north winds are expected each afternoon and this will likely keep coastal temperatures in the low 60s through Thursday. Friday may start to be a transition day with some marine influence returning to the Mendocino coast. Friday will be a tricky forecast day for the Humboldt and Del Norte coast. Winds will start to weaken and this may either allow temperatures to warm up into the 70s or stratus will form and keep temperatures in the lower 60s. Farther inland the warming continues with highs over 100 in many valleys Friday and Saturday. Moderate to locally major heat risk is expected to start on Thursday in most inland areas and continue through Saturday. One of the big factors will be the overnight lows. In the valleys the temperatures may end up dropping slightly more than currently expected and this could diminish the overnight heat risk. The details remain uncertain, especially in the coastal counties, but this is starting to look like it will be some of the hottest weather so far this summer. Heat advisories may be needed for some portion of the late week/weekend time period.

AVIATION

A storm system continues to move through the area early this morning bringing drizzle and LIFR conditions to primarily Del Norte and Humboldt counties. This system will move east Tuesday morning and high pressure will begin to build into the region. This will allow northerly winds to increase, especially along the coast, mixing out the low level clouds and resulting in VFR conditions for all of Northwest California by the afternoon. Stratus may redeveloped where moisture becomes pooled on the North side of the King Range Tuesday night with IFR or MVFR ceilings possible again at ACV.

MARINE

Southerly winds are generally subsiding over the coastal waters and beginning to turn out of the north behind a departing storm system. By Tuesday afternoon high pressure builds over the eastern Pacific allowing wind to increase, ranging from 15 kt in the north to 25 kt in the south. Winds will continue to build Tuesday night and Wednesday with gales expected at some point on Wednesday. Gale watches have been raised for all of the coastal zones except for the immediate Humboldt and Del Norte coastline. The winds are expected to remain near gale or gales into Thursday and possibly into Thursday night. Thursday afternoon the gales start to push farther off the coast and this will diminish the winds in the southern waters. Friday and into the weekend the gales are expected to push even farther offshore, although confidence is low on how far off the coast they will go. The gale watch in the northern outer waters zone currently ends Friday morning but gale conditions could continue through Friday night depending on the orientation of the pressure gradient.

FIRE WEATHER

Dry conditions will return Tuesday into Wednesday with temperatures warming considerably across the interior. By Thursday, high temperatures could be exceeding 100 degrees in some interior valley locations. This is expected to drop afternoon RH into the mid to upper teens Wednesday and low to mid teens Thursday across Lake county, eastern Mendocino and Trinity counties. Wednesday night into Thursday morning RH recoveries are only expected to be around 20 to 40 percent in eastern and southern Lake County as well as far eastern Mendocino County. Wednesday night northerly winds are expected to pick up over the higher terrain of southern and eastern Lake County as well up into the Yolla Bolla mountains of NE Mendocino and SE Trinity counties. Sustained winds of 15 to 30 mph with gusts to 40 mph in are expected in some areas. The strongest winds are expected to begin very early Thursday morning and start to taper off by mid to late morning. In general this looks on the low end of the red flag criteria and there is still some uncertainty on the fuel moisture so will continue to hold off on any fire weather watch.

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT this morning for PZZ450- 470.

Small Craft Advisory from 3 PM this afternoon to 2 PM PDT Wednesday for PZZ455-475.

Gale Watch from Wednesday afternoon through late Wednesday night for PZZ455.

Gale Watch from Wednesday evening through Friday morning for PZZ470.

Gale Watch from Wednesday afternoon through late Thursday night for PZZ475.