textproduct: Eureka

SYNOPSIS

Above normal interior temperatures continue today. Monsoonal and tropical moisture has arrived, bringing chances of showers and thunderstorms early to mid next week.

DISCUSSION

High pressure continues to build over the area, bringing warm interior temperatures into the 90s to just over 100 to most interior valleys. Minor to locally moderate HeatRisk is expected with this heat. Hazy skies are possible from fires in southern Oregon and northern California, but impacts are expected to be minor.

Monsoonal moisture has returned. While moisture aloft will be plentiful with PW of over 1 inch, instability is still meager. Some high resolution models do show a little instability (around 100-300 J/kg of CAPE) tonight into early Monday, and again Monday afternoon. Thunderstorm chances remain low at around 10-15% and one of the biggest uncertainties is the timing and location of these storms, should they form. Dry low levels will evaporate most precipitation and any thunderstorms are likely to be dry thunderstorms. A Red Flag Warning has been issued for this dry thunderstorm potential.

Moisture from Tropical Storm Elida continues to stream in Monday which will continue the threat for a few showers and thunderstorms. This trend will continue through Wednesday with shower and thunderstorm chances generally increasing each afternoon with Wednesday having the highest chances. Still, chances are low at around 15% mainly in Trinity County. Uncertainty remains high as the path of the remnants of Elida will strongly influence what areas see impacts. Some ensemble members show the center of the low very close to the shore of the North Coast.

Increased cloud cover and weaker high pressure will nudge interior temperatures closer to average, though most interior valleys will still see 90s. Most coastal areas will see highs in the 60s with overnight and morning stratus. /JB

AVIATION

Strands of moisture from the monsoonal origin are keeping cloud cover and visibility low as the high pressure sinks the layers towards the deck, stratifying clouds into low ceilings well into Monday. LIFR for the coastal terminals began during daylight hours Sunday early evening, showing the magnitude of the cloud layer and moisture advection. With the Tropical Storm Elida to the south we can expect several days of socked in/low vis flight conditions. Tempo groups are in place for the TAFs for 1/4mile fog but there have been periods of M1/4 and less for visibility at KACV and possible at KCEC as well. The southerly flow usually brings this type of cloud regime if moisture is available. /EYS

MARINE

Northerly winds continue to gradually ease and move farther off the coast. Still, the outer waters remain hazardous to small crafts through Monday afternoon and so the SC.Y has been hoisted. Winds continue to ease Monday with peak gusts of 15 kts or below likely for all waters. Nearshore winds will be relatively light, and could be southerly along the coast as eddies form. Winds will generally be mild for much of the week.

Seas remain characterized mainly by decaying northerly wind waves and small mid to long period northwesterly and southerly swells. Steep seas will slowly ease in the outer waters today and be relatively mild by Monday. A larger southerly swell, peaking at 4-5 ft from Tropical Storm Elida arrives Monday and continues for much of the week. With relatively light winds, seas could be dominated by this swell. This could create some larger breakers than usual on the southern facing beaches, especially south of Cape Mendocino.

EKA WATCHES/WARNINGS/ADVISORIES

CA... Red Flag Warning until 6 PM PDT this evening for CAZ403-406- 409>412.

NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 8 AM PDT this morning for PZZ450.

Small Craft Advisory until 3 PM PDT this afternoon for PZZ470-475.