textproduct: Eureka

KEY MESSAGES

* Breezy afternoon winds will elevate fire weather concerns for Trinity county Monday afternoon.

* Warm temperatures to continue Monday before much cooler temperatures arrive in the area.

* Isolated thunderstorms are possible Tuesday afternoon and evening.

* An early season reason may bring widespread rain to the area Wednesday night and Thursday.

SYNOPSIS

An approaching upper low will deepen the marine layer Monday. A few showers are possible Tuesday and Tuesday night as this low moves overheard. An early season storm is expected to bring a widespread wetting rain Wednesday afternoon through Thursday, although uncertainty remains on how far south it will make it.

DISCUSSION

Ridging over the area is bringing warm temperatures to the area today and this will likely be the warmest day for a while in most areas. Tonight and Monday an approaching trough is expected to deepen the marine layer and bring some cooler temperatures to much of the area. This is also expected to bring some increased winds in the afternoon. These will be west to southwest and this will help to increase afternoon RH. For more details see fire weather section.

Tuesday is expected to see moisture aloft increasing as the trough cuts off and moves towards the coast. A shortwave rotating around the low may provide enough lift with some instability aloft to produce a thunderstorm or two. These may be fairly dry initially with PWATS around 0.6 or 0.7 inches. Currently the models are showing some convective precip Tuesday evening , but the profiles don't look very favorable for thunderstorms. So this will need to be monitored. At this coast this may bring some light rain or drizzle. Later Tuesday night some light rain is possible in the interior areas as well.

Wednesday it generally looks like there may be a break between this trough and the next on. Wednesday evening and overnight into Thursday the system is expected to bring a wetting rain to much of the area. The models are still struggling with how far south this rain will make it. The NBM is showing over a 60 percent chance of a wetting rain for most areas north of Willits by Thursday afternoon. Most of Humboldt county is showing a 60 percent chance of over a half inch of rain. Farther north in Del Norte county there is a 70 percent chance of over an inch of rain. Some of the models are still showing drier solutions so this will need to be monitored as it gets closer. Late in the week and over the weekend another system moves by to the north, but at this point it looks like any significant precip will remain north of the area. MKK

AVIATION

Stratus is expected to return this evening or tonight and become fairly widespread towards morning. With the approaching trough we are not expected a lot of low fog, but more just IFR or LIFR CIGs. Monday the stratus may linger at the coast through much of the day, although the CIGS will likely lift to IFR or MVFR. Areas farther inland, including UKI, are expected to remain clear through Monday. MKK

MARINE

Strong to near gale force winds continue across the waters this afternoon. These are expected to start diminishing tonight near the coast and more broadly on Monday. These are expected to become southerly near the coast. Wind driven waves are around 7 to 10 feet and are expected to diminish tonight and Monday along with the winds. A southerly swell of 2 to 3 feet at 17 seconds continues as well. This will slowly diminish over the next several days.

Tuesday an early season weather system starts to approach the area switching winds across the area to southerly. These southerly winds are expected to slowly increase through Wednesday afternoon. Current models showing them peaking around 20 to 25 kt in the northern waters. Some models are showing these southerly winds reach 30 kt Wednesday afternoon. These southerly winds are expected to continue through the week, although for now it looks like they will remain under 15 kt or so. Next weekend northerly winds may return. MKK

FIRE WEATHER

Hot weather and low RH continue today. Monday an approaching upper level low will enhance and deepen the marine layer. This will cool temperatures slightly across the area with more cooling in the near coastal areas. Tuesday additional cooling is expected. Low level RH is expected to be much higher, only dropping to around 35 to 50 percent in the afternoon. Late Tuesday afternoon and Tuesday night the upper low moves overhead bringing the potential thunderstorms. There is not much instability so this may end up just being a few light showers or even just some virga. There are some dynamics with the low which could help make use of the instability at higher levels. Still the threat for thunderstorms looks fairly minimal.

Wednesday afternoon or evening there is the potential for some widespread wetting rain. At this point there is still quite a bit of uncertainty on how far south it will make it. Probabilities drop off quickly in southern and eastern Lake county. Rainfall amounts over an inch are possible in Del Norte county. Some of the models are are still showing a drier solution with precip only making it into northern Humboldt and northern Trinity counties. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 PM PDT this evening for PZZ450.

Small Craft Advisory until 9 AM PDT Monday for PZZ455-470.

Small Craft Advisory until 3 PM PDT Monday for PZZ475.