textproduct: Eureka

KEY MESSAGES

* Thick smoke remains stuck around the Hoopa Valley stretching from as far north as to Orleans as far south as Burnt Ranch. Weak transport winds will keep smoke here through the week.

* Interior areas will remain warm Thursday, although some of the near coastal areas will start to see some cooling as the marine layer expands.

* Another trough is expected to bring below normal temperatures and very slight potential for a isolated thunderstorms Friday.

SYNOPSIS

An approaching trough will start to deepen the marine layer Thursday. Friday this will bring a slight chance for thunderstorms and cooler temperatures. The coolest day is expected to be Saturday highs mainly in the 80s across the interior. High pressure starts to build back into the area warming temperatures again Sunday and Monday.

DISCUSSION

The upper level ridge is starting to get pushed out of the area as an upper level low approaches the area. This is expected to deepen the marine layer and start cooling off some of the near coastal areas. Typical afternoon west to southwest breezes are expected.

Thunderstorms are possible as early as Thursday night into Friday the upper level is expected to move closer to the coast. The models are showing some of the ingredients for storms. The ensembles show fairly high confidence that there will be some increase moisture aloft. There is some vorticity from the low and there is an upper level jet moving overhead. For now it looks like instability will be the limiting factor. The NAM is showing 100 to 300 j/KG of MU CAPE at times Thursday night and Friday. However this does seem to be an outlier with the other hi-res models not showing it. Went ahead and added a slight chance of thunderstorms to northern Trinity county Friday afternoon and evening. If the instability does materialize, the forecast may change quickly. This low will also continue to deepen the marine layer and bring cooler temperatures to the inland areas. Highs may be in the upper 80s to low 90s.

Saturday the upper level low starts to move out of the area. Temperatures are expected to remain slightly below seasonal normals in the mid to upper 80s to around 90. Sunday and Monday temperatures are expected to warm back into the 90s in most areas. This may briefly help to bring some offshore that would help clear out the coast. Mid to late next week cooler temperatures are expected as zonal flow takes over the ridge gets squashed down. MKK

AVIATION

The stratus is bringing LIFR conditions to the coastal areas this morning. Conditions are expected to lift this afternoon as clouds push back towards the coast, however it is not looking like there will be any significant clearing in the afternoon. Clouds may lift to IFR conditions. Tonight the stratus is expected to persist, although CIGS may not be quite as low as this morning. The approaching trough may help to lift them slightly. MKK

MARINE

Winds and seas are expected continue to diminish Thursday and be exceptionally low on Friday. These are expected to continue to be low Friday night. The waves are also slowly diminishing, but are taking their time in the northern waters. Saturday it looks like the northerly winds will start to increase again. This will start in the southern waters and spread north Saturday night into Sunday.

There are currently two swells moving through the waters. One is around 2 or 3 feet at 11 seconds out of the northwest and the other is around 2 or 3 feet as well, but out of the south at around 14 seconds. These generally expected to persist for the next several days. MKK

FIRE WEATHER

Hot and dry weather held on for one more day longer than initially forecast with the hottest valleys reaching near 100 F and some RH values in the upper teens. Thermal belts, however, are expected to begin weakening tonight, slightly improving poor mid and upper slope recoveries. Winds remain weak and terrain driven. Conditions will generally ease through the end of the week with increasing marine influence. Weak transport wind will continue to allow smoke accumulation around the MP18 fire in Hoop and up the Trinity River Valley, creating some extra, localized moderation of conditions. There is also a small chance for thunderstorms on Friday, for details see the main discussion. MKK/JHW

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 5 AM PDT Thursday for PZZ455.

Small Craft Advisory until noon PDT Thursday for PZZ475.