textproduct: Eureka

SYNOPSIS

Temperatures are expected to warm to the upper 90s to around 100 in interior valley locations by Thursday and into the weekend. Breezy winds are expected along the coast during the afternoon and evening through the weekend. High temperatures in the upper 60s to around 70 degrees can be expected along the coast, warmest possibly this weekend.

KEY MESSAGES

- Temperatures will warm quickly with moderate to major HeatRisk expected Thursday through the weekend and into early next week.

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

- Breezy winds are expected along the coast again Thursday afternoon.

DISCUSSION

The offshore wind component will keep skies mostly clear overnight. The drier air mass from the interior will keep temperatures warmer overnight and keep low level moisture from taking advantage of longwave radiative cooling due to the lack of cloud cover. A few clouds are possible around the Eel River Delta and other areas near the coast and in the river valleys.

Thursday afternoon high temperatures in many areas are expected to be nearly 10 degrees warmer than today. Some of the warmer valleys will be approaching 100. This may be the hottest day for some of the near coastal valleys such as Gasquet, Garberville, and Boonville. At the immediate coast temperatures may reach the mid to upper 60s, but the breezy northerly winds off the water in the afternoon will likely keep them from getting much warmer. Thursday night into Friday morning temperatures are generally expected to be in the 50s in the valleys with temperatures remaining near 70 on some of the ridges. The heat advisory remains on track in southern Mendocino and Lake counties. Friday afternoon the marine layer may start to influence western portions of Mendocino county keeping temperatures slightly cooler.

Saturday a weak shortwave moves down from the north and this may slow the warming or keep some areas slightly cooler. This could potentially spark off some thunderstorms, but at this point it looks like it will be too dry aloft and the threat will be well to the east of us. Monday and Tuesday the heat continues to build and more heat advisories or even a warning may be needed for this area. This currently looks like they will be the hottest days. Wednesday now looks like it might be the start of the cooling trend. MKK /EYS

AVIATION

The coastal terminals may get a few obscurations, bringing prevailing VFR conditions down to MVFR for a few hours overnight. The persistent high pressure dome will steepen the pressure gradient near the coast, returning gusty offshore winds for the next several TAF periods and particularly during daytime hours and easing in the twilight hours. Weakening of the High pressure contours will bring a contortion of sorts, altering the northerlies by the end of the weekend, likely to be a continuation of offshore flow. VFR mostly expected for the area terminals. /EYS

MARINE

Northerly winds are increasing to near gale and gale through the next few days. The waves will become dominated by the steep short period waves, but currently there is still an 18 second southerly wave and a northwest swell 5 feet at 10 seconds. Winds will increase again on Thursday near the coast.

Friday the strongest winds are expected to start pushing farther off the coast south of Cape Mendocino. So we have extended the gale warnings, but only through Thursday night for the southern outer waters. The stronger winds are expected to linger in the northern outer waters through Friday night and possibly longer. Currently it looks like the gales will continue beyond 10 to 20 nm north of Cape Mendocino on Saturday, then start to diminish on Sunday and this allows a southerly surge to move northward. Winds are generally expected to remain lighter into early next week. MKK

FIRE WEATHER

Temperatures are expected to continue to warm Thursday by 10 degrees or so. Along with the warming temperatures, very dry air is expected to move in and this will lower RH each day. The ridges are expected to see poor RH recoveries by Thursday morning. This will combine with some northerly winds over many of the higher ridges. The strongest winds are expected to be in the Yolla Bolla's and down into the higher terrain of eastern and southern Lake County. The red flag warning remains on track for tonight. Fuels are likely still marginal, but winds of 15 to 30 mph and RH expected to increase only to 20 to 40 percent is concerning enough to highlight the threat with a red flag product. Thursday afternoon RH is expected to drop into the low teens in much of the interior valleys. The winds are expected to diminish by the afternoon, however they may remain strong in eastern Lake county so have extended the red flag warning into the afternoon for zone 419. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... Heat Advisory from noon Thursday to 10 PM PDT Friday for CAZ113-114-118>120.

Red Flag Warning until 9 AM PDT Thursday for CAZ420.

Red Flag Warning until 5 PM PDT Thursday for CAZ419.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 10 PM PDT Thursday for PZZ450.

Gale Warning until 3 AM PDT Thursday for PZZ455.

Small Craft Advisory until 9 AM PDT Thursday for PZZ470.

Gale Warning from 9 AM Thursday to 3 AM PDT Saturday for PZZ470.

Gale Warning until 3 AM PDT Friday for PZZ475.