textproduct: Eureka

SYNOPSIS

Warmer and drier conditions will build and persist through Tuesday with night and morning valley and coastal fog. Wet and unsettled weather conditions will impact the area mid to late next week, bringing heavy rainfall, mountain snow and multiple periods of strong south winds.

DISCUSSION

High pressure is building over the area today. This brought valley fog to most of the inland valleys and some patchy fog along the coastal areas. This has taken some time to clear, but as of noon it appears to have all cleared. Highs are expected to warm above normal each afternoon and into the 70s. The lingering inversion may slow the warming and therefor the afternoon high temperatures today. High pressure is expected to persist on Sunday and conditions are expected to be similar across the area. Expect there will be another foggy night in the inland valleys. Monday it looks like a weather system will move by to the north of the area. At this point it looks like this will only have very subtle affects on northern CA, slightly cooler temperatures and possibly some more coastal stratus. Tuesday this moves east, but a stronger trough starts to approach the area. Conditions will generally be similar on Tuesday, but there winds may start to turn southerly and high clouds might start to move in. Valley fog is expected each morning, although coverage might be slightly less each day as it dries out.

Wednesday frontal boundary ahead of the next upper level is expected to approach the area bringing rain and strong winds. Current models are showing the rain start on the south slopes as early as late morning with most areas hold off until mid to late afternoon. Moderate to heavy rain is expected across the area Wednesday night into Thursday morning. This looks like a strong system that will bring fairly heavy rain, but overall it doesn't look as strong as the system that we saw earlier this week. Integrated Vapor Transport (IVT) values are still expected to be fairly high with a 60 percent probability of them exceeding 500 j/kg/s. The models are generally showing 1 to 3 inches of rain with local amounts up to 5 inches in the mountains late Wednesday evening through Thursday morning. This may cause some flooding in small stream and urban areas, but is generally not expected to bring river flooding. Snow levels are expected to be high with the first round, likely over 7,000 feet. Thursday night and Friday additional rain and mountain snow are expected. Snow are expected to fall behind the front, but not too far. Current models are showing them fall to around 4000 to 5000 feet, lowest in the north. This is lower than previous model runs were showing. Strong winds are also expected with this storm. The 12Z GFS shows a low dropping to 997 mb and moving onshore just north of the area. This is bringing 925 MB winds just off the coast of over 70 KT. This is just one model solution, but there is some support in the ensembles as well. The full ensemble mean for 925mb winds shows 50 kt off the Del Norte coast. Although this is lower, it is the mean and still gives support to the GFS model solution showing it it is not much of an outlier. This scenario could reasonably bring gusts of 40 to 60 mph to coast and coastal ridges with the higher end of the range on the coastal ridges.

Thursday night into Friday the colder air starts to move into the area. This brings the potential for lower snow levels, however it is uncertain how quickly the precip will come to an end. There is the potential for snow as low as 4,000 feet, but this is highly uncertain at this point. The models have started to trend lower with the snow levels. MKK

AVIATION

Shallow fog and low stratus along the coast in the early morning has quickly burned off through the day, finally allowing for widespread and clear VFR conditions all across the area with only thin upper level clouds in the sky. There is a very slight chance (less than 20% chance) of patchy, IFR ground fog tonight along the coast and in valleys, but persistent VFR conditions are most likely through the weekend alongside mostly calm winds. /JHW

MARINE

The sea state continue to be controlled by a very slowly diminishing mid period westerly swell around 8 feet. Otherwise, calm northerly winds will be to week to generate any short period seas, helping to create an unusually calm sea state through early Monday morning. Moderate northerly winds will build int he southern waters Monday afternoon and slowly spread north by Tuesday, most likely building short period seas back above 6 feet alongside continuing, mild northwest swells. Much steeper seas will return late next week as another storm system most likely (65% chance) brings gale force southerly winds around Thursday. /JHW

COASTAL FLOODING

King tides have persisted for one more day today, though increasingly small tidal anomalies due to weaker winds have allowed for the peak tide to drop closer to only 8.8 feet today, translating to only very minor impacts in even flood prone areas. Tides will continue to decrease over the next few days with no notable coastal impacts expected. The next King Tide will return the first week of December. /JHW

EKA WATCHES/WARNINGS/ADVISORIES

CA... Coastal Flood Advisory until 2 PM PST this afternoon for CAZ103.

NORTHWEST CALIFORNIA COASTAL WATERS... Coastal Flood Advisory until 2 PM PST this afternoon for PZZ415.