Saturday, July 26, 2008

August Outlooks



Note: These are my first attempt at long range forecasting. They are highly experimental, and I am trying these to see if I have any skill in long range forecasting, and if I will be making these maps monthly.
Discussion:
During the month of August, it appears that there will be a large ridge over the western US, and an occasional trough trying to dip down over the GLs/NE. It appears that from time to time, the ridge in the west may try to build east for a couple days, but nothing persistent. In the west, there will be a dry SW flow on the west side of the ridge. I have put the coast in slightly lower temps than the rest of the west due to the cooling effects of the Pacific. However, in the rest of the west, under the ridge and with a SW flow, it looks like it will be warm and fairly dry. So, I put much of the inter mountain west in above normal and fairly dry conditions. In the extreme NW, a trough may be trying to build down, so I added normal precip and near normal temps. In parts of the SW, I did not go crazy with temps and added in normal (may end up busting a little above) precip, due to the monsoonal flow. Now, you may be wondering why there is a large area of below normal on the edge of the heat ridge and well above normal precip. Well, it looks like it will be quite stormy on the northern edge of the ridge, as it usually is. Which is why I put in below normal temps and above normal precip in that area. The above normal precip I have fairly high confidence in. However, I am a little concerned that the temps may end up being closer to average instead of below average in that area, due to warmer night time minimums, even if day time maximums are below normal. In the south central states, I put in above normal temps and below normal precip. The flow around the high the majority of the time will be out of the NW, which is a fairly dry flow, so I expect fairly dry conditions in that area with above normal temps. In the NE, I added above normal precip and put in above normal temps for most of the NE, but with a small area of cooler weather noted closer to the Canadian border. This is because a trough will be effecting the area from time to time, which easily agrees with the above normal precip. However, why did I put in above normal temps? A few reasons...one of the big reasons is despite the troughiness for the majority of the summer, temps have been normal to above normal in the NE, mainly due to nighttime lows being warm. Although I really have no reason to explain it, this reason made me lean against below normal temps. Another reason is, the heat ridge may try to build east from time to time, causing above normal temps as that happens. The third reason...which may just by me going out on a limb...the models are hinting that the trough axis may try to setup a little farther west...over Ontario/the northern GLs...opposed to Quebec...this would put the NE US in a warm, moist SE flow ahead of the trough. So, on a perhaps slightly shaky decision, I went with above normal in much of the NE/Mid Atlantic for these reasons. NOTE: I CAN SEE HOW THIS CAN LEAD TO A BOUT OF MAJOR HEAT IN THE EAST. And in the SE I went with above normal temps and normal precip because the ridge will extend east into the SE.

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