textproduct: Eureka

KEY MESSAGES

* Mainly dry and unseasonably warm weather is expected through midday on Thursday.

* Moderate to heavy rain and gusty south winds across much of the area Friday and Friday night.

* Additional rain and wind possible over the weekend.

SYNOPSIS

Dry weather is generally expected through Thursday along with above normal temperatures. Friday and Friday night a strong storm is expected to bring moderate to heavy rain across the area and strong southerly winds. Additional rounds of wind and rain are possible over the weekend.

DISCUSSION

The front that brought rain to Humboldt, Del Norte and Trinity counties today has moved out of the area and widespread low cloud have settled in across the area. These clouds are expected to clear out today, but this may take until midday in some of the deeper northern valleys. Highs are expected to be in the mid 60s in the north to upper 70s in the south. The valleys that are slow to clear out may not reach their expected temperatures and RH may be higher than expected. Wednesday conditions are expected to be fairly similar, although there may be less valley clouds around in the morning. Thursday the first chance for rain shows up in the afternoon, however it looks like it will just be a few light showers or sprinkles along the coast. High clouds are expected to increase through the day, but still it looks like another warm day across the area. South winds are also expected to increase across the area.

The probabilities for rain have increased across the area for rain on Friday and Friday night. In the past 24 hours forecasted rainfall totals have increased notably. Now the NBM is showing over an inch in eastern Lake county to over 3 inches in Del Norte county for the 24 hours ending at 4AM Saturday. There is still quite a bit of variability in the models on these amounts and this is a middle of the road amount. Plenty of ensemble members show the potential for higher amounts, although the 12Z ensembles are not showing particularly high Integrated Vapor Transit values. The plumes are showing around 500 kg/m/s, but this may increase with the next run. The ECMWF EFI is highlighting this rainfall and this is the first time it has highlighted precip this month. One unusual thing is how much instability there is with this system on Friday and the NBM is showing a 15 percent chance of thunderstorms. This is not something typically expected from a pattern like this, but there is some instability so it will need to be watched. The impacts of this rain may be more limited than they would be later in the season. Creeks and streams are very low and the soil is very dry limiting the potential for flooding, at least with this first system.

In addition to the rain, winds will likely be a factor, especially in Humboldt and Del Norte counties. The 850 MB winds on the GFS are over 60 kt Friday morning along the Humboldt coast. This is backed up by the NBM with a widespread area of 40 to 50 mph gusts expected. This will likely produce more impacts as it will be the first strong southerly winds of the season.

Right on the heels of this system another one is expected. Currently it looks like this one will be weaker than the one on Friday, but this will need to be watched as it gets closer. Currently the NBM is showing 0.75 to 2 inches of additional rain, heaviest in the north. This one looks wind as well. MKK

AVIATION

With the rain today there is a lot of moisture around, but it is changing a lot. Expect towards morning it will settle into IFR. This is expected to scatter out by mid to late morning as the south to southeast winds start to pick up to around 10 to 15 kt in KCEC and lighter to the south. The inland valleys are seeing a lot of fog this morning and it may make it into UKI early in the morning, but confidence is low on this. This evening it looks like stratus will return along the coast, but this could be delayed and/or limited by some weak offshore flow. MKK

MARINE

Southerly winds of 10 to 15 kt persist in the northern waters with lighter winds to the south. The current swell around 7 to 8 feet at 14 seconds will be reinforced by a new swell this afternoon and tonight. This will build the swell to around 10 to 12 feet at 14 seconds. Tuesday night and Wednesday southerly winds are expected to be pick up in the northern waters to around 20 to 25 kt. A small craft advisory has been issued to highlight this and the swell over 10 feet. Wednesday and Thursday the southerly winds of 20 to 25 kt continue to expand into the southern waters. Thursday night into Friday the models are now showing more confidence in gales moving into at least the northern waters.

The first round of southerly gales diminishes Friday afternoon and then the post frontal swell is expected to move into the waters. The current model shows this build to over 25 feet. This is still a ways out and there is still lots of time for it to change. Additional gales are possible Saturday afternoon and overnight. MKK

COASTAL FLOODING

Water levels inside Humboldt Bay continue to run 1.2 to 1.5 feet over the astronomical tides. Winds will continue to be southerly which tends to increase water levels slightly. High tides drop each day through the weekend. The water levels are expected to be slightly below 8.8 feet the next couple of days around high tide (11/10 @11:45am, 11/11 @12:06pm, 11/12 @12:55pm). The high tides will continue to diminish into the weekend. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 PM PST this evening for PZZ450- 455-470-475.