Lots of Thunderstorms, But Big Storms Avoid Portland

May 4, 2017

10pm…

Thunderstorms popped up all over the place this afternoon and evening, with numerous severe thunderstorm warnings issued by Portland/Seattle/Medford NWS offices.  In our area Vernonia saw 1″ hail, 1.3″ hail fell near Carson, and two tornado warnings were issued around Crater Lake.  No tornado was actually seen, just indicated as a possibility on radar.

The far westside of the metro area saw hundreds of lightning strikes around 6pm as a cluster of storms moved north there.  In the central Gorge a severe storm moved through and sure looked dramatic in a pic from Julie Vance:

That led to some flash flooding and mudslide in the Dodson area…as if the 2″ of damaging ice wasn’t enough in January…

Yet we seemed to have a “dome” over the metro area.  Check out the lightning strikes today (cloud to ground only):

Apparently Yamhill and Carlton were the places to be if you wanted to see a light show?  I suppose Government Camp would have worked as well.

There is a new batch of weaker thunderstorms moving up the Cascades right now and we’re seeing lots of flashing from the metro area…enjoy the light show!

Check out the hot temps in parts of Oregon today:

Things will gradually die down overnight and we’re back to typical cool showers tomorrow.  It should be a refreshing day compared to today.

Chief Meteorologist Mark Nelsen


A Crazy Afternoon & Evening Ahead

May 4, 2017

3:20pm Thursday

I hope you’re enjoying our summer day…on this May 4th.  We’ve reached our 83 degree forecast high here in Portland, making it the warmest day of the spring so far.

Thunderstorms have arrived earlier than expected and farther west too!  Several severe thunderstorm warnings have already been issued by the Portland NWS the past 2 hours, mainly for large hail around Elsie, Mt. Hebo, and north to the Columbia River.  Most of the big storms have been over the Coast Range and just inland from the Coast…SO FAR.   Here in the valleys we’ve seen sprinkles and a lightning strike or two but as of this hour its real quiet.

I think that will change as we head into the commute and early overnight hours.  The atmosphere is primed for thunderstorms to pop up just about anywhere during these next 8-10 hours.  Plenty of moisture, “heat”, and cooling coming in high above our heads leads to a very unstable atmosphere.  These storms are moving quickly from south to north, so even though you may get a torrential downpour in this subtropical airmass, it shouldn’t last too long.

Take a look at the GOES-16 visible loop and you can see plenty of clearing through the Willamette Valley right now which will keep temps up and help initiate more thunderstorm action.

CODNEXLAB-GOES16-Visible-21-57Z-20170504_415-469-10-100

Radar at 3:10pm also shows that window to our south

KPTV 2017 Default Earth

To summarize:

  • ANYONE in our viewing area could see a thunderstorm between now and midnight.
  • ANY thunderstorm could turn severe, which means it would contain strong wind gusts (over 58 mph) or large/damaging hail (1″ or quarter size).  When the NWS sees a storm which could contain either of these, it issues a Severe Thunderstorm Warning
  • Local flooding is possible if a thunderstorm passes over your neighborhood…expect Florida-style raindrops this evening!
  • AFTER midnight the cool air surging in from the Pacific Ocean down here near sea-level will stabilize things and thunder chances end west of the Cascades

Remember that we are on Facebook and Twitter as FOX12WEATHER.  Make sure you like/follow us there (seen to the right as well) since we tend to update those sites more frequently.  I’ll be on-air 5-7pm and again 8-10 pm on KPDX and 10-11:30pm on KPTV.

Chief Meteorologist Mark Nelsen