26 Sept KPNS forecast
Post date: Sep 26, 2012 11:13:50 PM
running short on time this afternoon...no major changes compared with yesterday's forecast, flat ridge at the surface continues to slide east leaving little/no pressure gradient. higher theta-e air has moved back into the region. it appears that several showers either hit the airport or came very close, the clouds and outflow likely held their max temps a few degrees below what I was expecting yesterday. Clouds have basically cleared, so expecting radiative cooling tonight down to near their current dewpoint of 71 for a min temp. Forecast very similar to yesterday's, low level moisture certainly in place along with instability building up during the day. Expecting some cu to develop, but dry air aloft and lack of forcing for rising motion will limit the probability of precip to the 10-20% range indicated by MOS and NWS. Those areas that do get an airmass thunderstorm will likely have a lower max temp than areas that do not, little change is predicted in 850 temps by NAM, so mid-upper 80's seem reasonable again for tomorrow. I have been too high with my max for two days in a row, going to resist the temptation to "overcorrect" with a lower forecast today. Winds again should remain relatively light with a weakening pressure gradient, sea breeze and/or thunderstorm outflow will likely dominate the max wind ob tomorrow. Given today's clouds and precip and the cooler-than-guidance temps, I expect today's forecast numbers to have a bit more spread than in the past two days. My numbers are going to be very similar to yesterday's, except with a warmer min temp thanks to the high dewpoints currently in place.