textproduct: Eureka

SYNOPSIS

A slight chance for interior thunderstorms Tuesday afternoon with probabilities diminishing before sunset. High pressure continues to build. Drier weather returns at the end of the week.

DISCUSSION

As an additional low pressure ejects southward of the CWA, we can expect another round of daytime convection Tuesday for the interior. The top sector of the low will be pulling moisture with an easterly flow at the mid to lower levels. This perturbation will be slightly enhanced by bulk shear which could give a bit of slant, enabling some thunderstorm development. CAPE values are modest and most of the areas of risk are Trinity county as well as eastern Mendocino and Lake counties near the mountainous eastern flanks and boarders.

A shallow marine layer along the coast is expected mostly each night/early morning through the end of the week. Otherwise, a mostly dry set up for the weekend although there are decent signals for CAPE (~500j/kg), Saturday and Sunday. High pressure will continue to fill in for the next few days bringing warmer temperatures and likely driving up the CAPE values due to the buoyancy of the air parcels. A lack of moisture and CIN will keep a lid on things. Model soundings do show inverted V's but without supercooled droplets or higher dewpoints there will not be enough moisture to pose any sustained or high confidence threats. /EYS

AVIATION

Mostly MVFR/VFR expected as the low ejects south. Terminals will have short periods of MVFR ceilings overnight into Tuesday morning. Expect a winds to shift to an easterly bearing overnight as the northernmost edge of the low pulls a CCW flow back into the area terminals, primarily on the coast. Model guidance indicates moisture will once again increase overnight into Tuesday morning, allowing potentially MVFR ceilings to redevelop, particularly north of Cape Mendocino along the Humboldt and Del Norte coasts. Surface condensation pressure deficits are not very low, likely indicating a stratus deck rather than surface fog.

MARINE

The coastal environment will be dominated by lowering pressure across the interior west and high pressure building over the eastern Pacific. This will allow the pressure gradient to tighten over the next several days and north winds to ramp-up to near gale or gale on Friday into Saturday. Steep seas will build in response to the winds with seas exceeding 10 feet at around 8 to 9 seconds in the outer water zones. Local model guidance has been trying to push for larger waves approaching 15 feet in the outer waters on Friday. Either way, the seas will be steep and either hazardous seas warnings or gale warnings will likely be needed late in the week into the first part of the weekend for at least the outer water zones. /RPA

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 1 PM this afternoon to 11 PM PDT Wednesday for PZZ470.

Small Craft Advisory until 11 PM PDT Wednesday for PZZ475.