textproduct: Eureka

SYNOPSIS

Monsoon moisture is bringing widespread high clouds this afternoon and this is expected to continue through Wednesday. Slightly above normal temperatures continue Tuesday. There is a slight chance for afternoon thunderstorms in the interior Tuesday and Wednesday. Drier weather is expected late in the week with temperatures near or slightly below seasonal normals.

DISCUSSION

Warmer temperatures are expected again Tuesday with highs in the warmer valleys in the mid to upper 90s. Tuesday late in the afternoon and evening some of the models are showing a small amount of instability, but there really isn't any forcing to set off a thunderstorm. Still one or two are possible in northern Trinity county in the evening.

Wednesday the area of low pressure starts to move past the area and this is expected to bring a little bit of forcing and some instability in the afternoon and evening. This looks like the most likely time for thunderstorms to develop this week. However, if any storms do form they will be moving north and may move into Siskiyou county fairly quickly.

Thursday the upper level trough is expected to get closer to the area and this is expected to start bringing cooler temperatures, back to near or slightly below normal with highs in the upper 80s. This is expected to bring some stronger wind west to southwest winds in the afternoon. Similar temperatures and winds are expected to continue on Friday. For details see the fire weather section. High pressure is expected to bring warmer temperatures to the area for the weekend with dry weather.

AVIATION

Larger scale synoptic pattern of ridging is likely influencing the lack of cloud cover forecasted by model guidance. Timing could be the culprit as lower ceilings and overcast cloud cover have a higher probability of occurrence into the 12z-15z range for KACV and KCEC. Despite having plenty of available monsoonal moisture approaching from the south, subsidence does seem to be sinking the air and clearing things out late into Monday night/Tuesday early morning. The deepening of the marine layer could also factor into ceilings not dropping as well. That said, profiling radar has a sub 2000 ft moisture height near Bodega Bay which does not translate to advecting cloud cover for KUKI. Remote sensing will be crucial in observing and staying on top of TAFs overnight. /EYS

MARINE

Light northerly winds continue on the offshore waters, but closer to the coast winds are light and south to southwest. The steeper wave groups have diminished as well. A 3 to 4 foot southerly swell at 12 seconds is moving through the waters along with a 2 foot northwest swell.

These conditions are generally expected to continue through much of the week. The swells will fluctuate slightly, but generally remain small. Winds are expected to increase slightly to 10 to 15 kt Tuesday night and early Wednesday before diminishing again to less than 10 kt. Thursday afternoon northwest winds start to pick up once again in the southern waters to around 10 to 15 kt. Winds continue to increase over the weekend. MKK

FIRE WEATHER

Monsoonal moisture has brought widespread high clouds to the area this afternoon. There is still the potential for a few dry thunderstorms this evening, but the chances are diminishing due to very limited instability. Tuesday There is another chance for thunderstorms, but this looks like a low probability. Some weak ridging pushes over the area keeping the strong inversion at higher levels. Did add a slight chance for northern Trinity county late in the afternoon and evening. Wednesday the upper level low related to the departing tropical system moves closer to the area and increase the potential for some thunder in the afternoon. Confidence remains low on this, but have added thunderstorms to the forecast Wednesday afternoon and evening.

Thursday and Friday the threat for thunderstorms diminishes, however some stronger west to southwest winds are expected. At this point it looks like the RH will be too high to warrant a fire weather watch. Will likely add a headline to the forecast once it gets within range of the higher resolution models if the winds remain in the forecast. MKK

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... None.