Skies
cleared out and winds calmed down last night, allowing it to cool down
to 38F. There weren’t as many low-mid level clouds as many models
expected, and bright sunshine allowed a warmup to 55F before the sea
breeze got going in the early afternoon, with a maximum wind of 17 kt so
far. As the surface high moves eastward to just north of KCEC,
lower-tropospheric winds will shift to easterly downslope winds. This
will limit radiational cooling somewhat tonight despite clear skies,
though given the complex terrain, there is always the chance that winds
calm down right at the surface with the nocturnal inversion just enough
for brief cooldowns, making for a tricky low temperature forecast.
The downslope winds and sunny skies will lead to a rapid warmup
initially tomorrow, before the sea breeze gets going. The downslope
winds and strong ridging aloft means that the air just above the surface
will be very warm, with any mixing of it down to the surface making for
a very warm high. However, this will battle with the sea breeze and
marine layer, which due to the ridging and downslope winds, will be
extremely shallow and difficult to model. This is especially important
at KCEC since KCEC is almost right on the coast, where the marine
influence is the strongest (out of land areas), and there will be a
strong temperature gradient there. The U.S. West Coast is one of the few
places where even on a sunny afternoon with high sun angle, the
boundary layer (portion that is well-mixed) can be extremely shallow,
due to the relatively cold ocean. I suspect temperatures will spike
quickly before quickly dropping as the surface winds shift from
northeasterly (downsloping) to northwesterly (onshore), and this spike
might be underdone on models. However, in any case, only the
high-resolution models will properly capture the gradient and exactness
of location required for forecasting at KCEC. Really tricky high
temperature forecast and I don't really have a good feel for it. The
surface northwesterly winds will be rather light due to the overwhelming
offshore and downsloping easterlies just above the surface (though
partially blocked by the terrain).
 |
| Source: PivotalWeather |
 |
| Source: weather.us |
No comments:
Post a Comment