LONG RANGE FORECAST THROUGH THE END OF SEPTEMBER - 9/19/2018
September is another bridge month. It takes us from summer to fall. It can also see the first cool temperatures arrive. Typically in September, temps are in the 80s and 90s at the beginning of the month for the valleys west of the Cascades, but drop sharply to the 60s and 70s by the end of the month. East of the Cascades 70s and 80s give way to plentiful 60s with some 50s on the coldest days east of the Cascades. The all time record for September in Medford is 110 which happened in 1943. Average rainfall for Medford in September is just over a half an inch, mostly due to thunderstorm activity at the beginning of the month. In many years September can be dry. Wet storms more typical of late fall into winter can arrive at the end of September bringing rain and snow for the mountains. That is not too frequent a happening however. Meteorological fall began on September 1st. And we have sure been seeing very fall like conditions. Seasonal fall arrives on the 23rd.
All it took to crush the hopes the graphics below represented was three days. When I posted what you see below on the 16th, we were looking at a scenario that seemed too good to be true. Take a look at it one more time.
Long range forecasting is a capricious business anywhere. But nowhere more so than here in Southern Oregon and Northern California. So those graphics you see above are now nothing but pipe dreams. The new data that has emerged shows up being above average for temps, and below average for precipitation. Exactly opposite of what is shown above. We are going to remain in a persistent ridge situation through at least the first week of October as it now appears. We will be warmer than average as well, and we might even see some days that could be considered hot. 90s in early October have happened in Medford. I am not expecting them right now.....but 80s look almost certain to happen. You can expect to see 80s west of the Cascades. Coos and Douglas Counties will see fewer days with 80 or higher. But, it looks like they will be seeing them. East of the Cascades we do expect that there could be some days reaching 80 as well. But, look for a lot of 70s. All of this does not sound all that bad really, until you remember that in late September and early October we really should be seeing 60s and 70s west of the Cascades and 60s to even upper 50s east of them. It is the longer nights and lower sun angles that are helping to keep temps down now.