A Few Thunderstorms

July 9, 2009

A brief "pop-up" thunderstorm near Mt. Hood
A brief “pop-up” thunderstorm near Mt. Hood

A nice little burst of convection early this afternoon to the east of Mt. Hood spit out a dozen or so strikes on the Mt. Hood National Forest.  One hour later though it’s gone.  I think that will be the story the rest of today and maybe tomorrow afternoon as well.  Lots of brief thunderstorms over the Cascades and east of the mountains.  I have a feeling we need to wait until Saturday for a better chance westside.  I do think Saturday is going to be a surprisingly hot day…maybe well into the 90s.  I’ll post more thoughts later. 

And…apparently those thoughts will be brief since it’s 11pm:

Upper level low is going to be slightly farther offshore the next 48 hours than what was forecast 24 hours ago, so heights are higher over us which means warmer temps.  Offshore flow looks real nice tomorrow and Saturday as well.  According to the “magic chart”, an 850 temp of 18-20 with offshore flow CAN get us to 95 degrees in perfect conditions.  90-93 is a better bet so obviously I’m shooting a bit high.  The 00z WRF-GFS has a strange shallow surge of marine air Saturday morning.  The NAM doesn’t show that and neither does the GFS.  As for thunderstorms, maybe something comes in Saturday night as the upper flow turns more southeasterly, especially if a major marine push holds off until sometime Sunday.  Lots of details to be resolved for Saturday night and Sunday…seems to be a low-confidence forecast for the 2nd half of the weekend.  Chief Meteorologist – Mark Nelsen