Underachieving Hot Spell

September 15, 2008

Moon The moon SEEMS really big tonight, so I figure it's worth a large picture.

Many of our viewers have been writing, wondering about the freakishly red full Harvest Moon.  It's due to smoke from the Rattle Fire, near Diamond Lake in S.W. Oregon.  The flow in the upper atmosphere has turned southeasterly, sending a surge of smoke north.  The flow stays generally the same way through Wednesday, so I think we have a smoky/hazy day on the way again for tomorrow.

Now…for the "cool" heat wave.  850 mb temp was 24.4 degrees at SLE this afternoon!  That is the highest on my September chart for the years 1997-2003…this is the warmest airmass you can get this time of year.  So why only 89 degrees?  Not enough easterly flow.  Anemic east wind only made it to Troutdale…just barely.  I looked at the maps from the 1981 heat…On September 15th that year we hit 96 at PDX.  I'm assuming the east wind made it to PDX that day.  This warm of an airmass would have produced a 100-103 in August.

No reason to think there will be any change tomorrow.  Easterly flow won't be any stronger, so that's why I left the high at 90.  Cooler starting Wednesday, then models are in disagreement from Thursday onward.  Mark Nelsen