October 2014 was the warmest October we’ve ever seen here in Portland. The records at PDX go back to 1940, so that’s quite a long time. The average temperature was 60.1 degrees, which totally blew away the 2nd warmest back in 1952.
Of course we also had our warmest August & September too, so this late summer/early fall period has been the warmest on record too. You can see the temperatures well above normal almost the entire month. Notice the low temperatures were only at/below normal the first couple days of the month. We’ve had night after night of temperatures in the 50s when it would normally be in the 40s or even some 30s. That ended this morning! Looks the low temperature finally made it down into the lower 40s this morning…for a few brief days we’ll be around normal.
But what’s ahead? More of the same…above average temperatures, especially in the higher elevations. Over the next two weeks models are in agreement that ridging and/or weak split flow will be the rule. That does not mean it’ll be dry, but upper-level heights are going to be above normal. That’ll weaken weather systems and the ones that make it through will be a little warmer than normal for this time of year. Not a big block in the atmosphere either, just warmer than average up above. I sure don’t see a great snowpack building in the Cascades the first part of the month if these maps are correct. Here is the 500mb anomaly chart from the GFS and ECMWF for 8 days from now:
and 15 days out…similar pattern
If this is the case, then much of what falls out of the sky will be rain at pass elevations for the next week or two, with some snow at times making it down to 5,000 to 6,000. But even at those elevations there would be rain at times too. Wednesday night’s 30 day run of the ECMWF implied this pattern would continue through about the 3rd week of the month,
then cooler for the 4th week.
Chief Meteorologist Mark Nelsen