A Crazy Afternoon & Evening Ahead

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

17 Responses to A Crazy Afternoon & Evening Ahead

  1. Lee Wilson says:

    The following is a personal observation starting around 8 15 lower clouds have reversed direction from South now coming in from the north and upper clouds going from South to North.

    Which either a )Shred the storm or B) create an unpleasant bit of business… Where ever the Apex joins up.

  2. Paul D says:

    Of course when I finally decide to leave the house the sky opens up and dumps big time!

  3. Boydo3 N. Albany says:

    Just happened to be drifting the Siletz today when a pretty good cell popped up. Kinda spooky being in a drift boat half way to the take out when all hell breaks out. But we decided that if our time had come, so be it and gradually worked our way down the river..

  4. Hal in Aims says:

    beautiful evening here….so far no action…closest was the big one that rolled just east of us and created havoc in Dodson and on to the north….

  5. Lee Wilson says:

    Well , that was a pleasant storm.
    We had winds that picked up to 25 to 30mph..had some lightning to.
    Glad to be any from that mini heat wave though. .

    But’ we did get free Air conditioning.
    We’re taking our system to 1, 500 watts.

    Or higher.

  6. Dave in SW PDX (235') says:

    Recorded a high temp of 86° around 3:30 this afternoon, much warmer than I expected. Down to 78° now with a 63° dew point. Sure feels like thunderstorm weather, but it looks like most of the action might have shifted to the north and east of the metro area. Langley Hill radar starting to show some echoes to the south of Portland, though, so we might see something in the next hour or so.

  7. Roland Derksen says:

    Quite a lot of cirrus overhead now, but I see mid-level (altocumulus type ) clouds on the southern horizon. I’d say by 6pm things should change quite a bit here. Present temperature: 79F

  8. W7ENK says:

    SEVERE THUNDERSTORM WATCH
    NATIONAL WEATHER SERVICE PORTLAND OR
    409 PM PDT THU MAY 4 2017

    https://inws.ncep.noaa.gov/a/a.php?i=11989755

    • Timmy_Supercell (Klamath Falls, OR) says:

      It just conveniently skips past Klamath/Lake Counties. 😉

  9. W7ENK says:

    Well, it’s a rare day our corner of the world ever gets this much weather scrutiny…

    http://www.spc.noaa.gov/products/md/md0648.html

  10. Jake-(Gresham near Nadaka Nature Park) says:

    Thanks Mark for the update! Always solid man. Appreciated.

  11. W7ENK says:

    Rock ‘n roll, folks!!

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