Warm & Humid Weather, and maybe a Thunderstorm

A quick check-in this afternoon. 

Today is the 5th day with above average temperatures here in Portland; it’s the first time we’ve had 5 consecutive warmer than average days since early March!  It shows how unusually cool spring and the first half of summer was.  The payoff has been the last 10 days as we’ve made quite a turnaround into typical summer conditions.    In fact this morning’s and yesterday morning’s lows (64 & 65 degrees)  were the warmest of the summer, due to quite a bit of moisture in the air.  It sure hasn’t been extremely humid even for us, but the air definitely has a “heavier” feel to it.

I see thunderstorms firing up over the Cascades and even some lightning strikes well offshore late this morning and into the afternoon.  We sure have the warm and humid conditions that make it “feel thundery”.   There is a very obvious upper level disturbance near Brookings at this hour, and it’s headed right up through Northern Oregon and into Washington overnight.  With nice lifting, lots of moisture to work with, and a warm airmass (no cool marine air to stabilize things), this CAN be a great setup for an overnight thunderstorms.  The curious thing is…none of the mesoscale models show anything to “write home about” the next 24 hours.  Generally they do quite well with this pattern, although a similar setup on Monday, July 25th gave us the surprise morning thunderstorms.  I would prefer to see a more southerly to southeasterly flow to give us nocturnal thunderstorms as opposed to the current south-southwest direction, but those late July storms came out of the southwest as the disturbance moved overhead.

So it boils down to “we MIGHT see a thunderstorm during the next 14 hours, but don’t get your hopes too high”.  That’s for west of the Cascades.  In the Cascades and eastside it’s a far more impressive pattern.  The latest mesoscale discussion from the Storm Prediction Center says “FAST MOVING MULTICELLS…AND PERHAPS A FEW SUPERCELLS…ARE EXPECTED ACROSS ERN/CNTRL ORE AND FAR SRN WA THROUGH THE REMAINDER OF THE AFTERNOON INTO EARLY NIGHT. ISOLATED DAMAGING WIND GUSTS AND LARGE HAIL WILL BE POSSIBLE WITH THE STRONGER STORMS. GIVEN THE LOW POTENTIAL FOR WIDESPREAD SVR…A WW WILL PROBABLY NOT BE NEEDED…BUT CONDITIONS WILL CONTINUE TO BE MONITORED.”

Hopefully we will see some excitement west side tonight since I’m not working this week and I can relax/enjoy from home like everyone else!  Otherwise enjoy the “sultry summer weather” since we’ll be back to the usual programming (clouds and cool) in no time at all I’m sure…September is only 1 week away.

Chief Meteorologist Mark Nelsen

312 Responses to Warm & Humid Weather, and maybe a Thunderstorm

  1. chiefWright says:

    http://tinypic.com/r/2lnixhs/7

    Sunrise this morning. Can’t really see it, but one of those cloud wisps is moving S and one is moving N

  2. Here is a radar loop showing the area of circulation

    Base Velocites confirms this

  3. chiefWright says:

    OK, probably should have tarped the hay, but decided to get some sleep instead. But now woken up by wind– getting very gusty out there, and flukey. There’s some low-level wispy clouds just to the SE with DEFINETE rotation, and the cloud bottoms look mammutus!

  4. Hmmm, not sure how long these will last, but 3 new tiny storms have fired just to the immediate south and also east of Salem.. C’mon lil guys!

    Odds are against them that they will weaken as they are fighting cooler air at low levels, stabilizing air mass with instability axis shifting east, and lift is weakening too.

  5. There could be a pretty big marine push in behind the ULL/storms, so don’t be surprised if we are nowhere close to the forecast 85-90 today.

  6. I’ve been outside the past… hour? .. seems like it.. Saw some amazing bolts, and tons of flashes… Sadly radar is showing an overall weakening trend with the two strongest storms over the Cascades east of Sandy, and the other near Mill City. Storms now moving NNE-NE as the ULL pulls inland further.

    • pappoose in scappoose says:

      Wake up Karl! Stray Albino Donkeys on the way. The palm trees may turn into PROJECTILES!

  7. chris s says:

    the cell just to the east down here in salem is putting on a pretty good light show right now.

  8. chiefWright says:

    Steady, light to moderate rain. Maybe will have more in the bucket tomorrow than I thought. And still the desultory spark to the S & SE.

  9. chiefWright says:

    Rain tempo now picking up; still just moderate, and the strobes on the Abiqua radio tower 5 mi S are clear. Generally if it’s going to be a gusher, they’ll be obscured.

  10. Kyle From Silverton says:

    As soon as I said something the rain started to decrease. Go figure. 🙂 0.80 of rain in half an hour!

    Good night. This is Triforce over and out.

    • chiefWright says:

      Almost an inch in Silverton? Thinking I’ll be lucky if there’s 0.1 tomorrow in the bucket here in Marquam.

  11. Austin(Cornelius) says:

    Expansion in size!

  12. EmzinTigard says:

    The lightning & thunder is picking up out this way..

  13. THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A

    * SEVERE THUNDERSTORM WARNING FOR…
    CENTRAL CLACKAMAS COUNTY IN NORTHWEST OREGON…

    * UNTIL 445 AM PDT.

    * AT 411 AM PDT…NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
    SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL…AND
    DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 6 MILES
    SOUTH OF THREE LYNX…OR 22 MILES SOUTHWEST OF GOVERNMENT CAMP…
    AND MOVING NORTH AT 20 MPH.

    * OTHER LOCATIONS THE SEVERE THUNDERSTORM WILL BE NEAR INCLUDE…
    RURAL EASTERN CLACKAMAS COUNTY…

  14. Sandi (Wilsonville) says:

    Lightning & thunder has settled down and it’s still dry out. Another flash just now so it’s not over. Pretty continuous lightning for a while there. It looks on radar that some heavy rain may still be coming our way.

  15. chiefWright says:

    Looks like NWS has expired the warning over N Willamette valley

    • chiefWright says:

      Lightning is now quite infrequent; mostly to NW, but occasionally S. Still waiting for that juice over Stayton to arrive; now that the temp has dropped may see more significant precip

  16. chiefWright says:

    It’s cooled down a lot, probably at least 10 deg in the last hour. I see a big wad of incoming juice over Aumsville/Stayton/Scio. Maybe I should get out there & tarp the hay…

  17. Annoyed says:

    Just got woken up by really loud thunder here in Canby.

  18. I would cancel the current Warning… Storm has weakened… Need to watch the other 3 closely, especially the 2 south of PDX metro.

    • chiefWright says:

      Yeah, if what’s passing over was the last NWS warning, it’s not even close to the winds & precip suggested. I haven’t bothered to run out and tarp my outside hay piles. Good light show, though.

  19. Sandi (Wilsonville) says:

    Woken up by lots of lightning!!

  20. chiefWright says:

    Just saw a beeeeg CG towards Woodburn

  21. 3 new big storms. May need a warning for Clackamas County or Marion/Western Linn.

  22. chiefWright says:

    Winds & rain still light. Still sparking out there, but frequency continuing to decrease… Yikes, never say never; another big burst N of Mt. Angel

  23. 12z Mesonalysis 500Mb chart shows temps aloft down to -13c, Mid-Level Lapse Rates 7.2C/km and Compact, dynamic lift has moved inland. Additional Severe Storms/warnings are possible.
    http://www.spc.noaa.gov/exper/mesoanalysis/s11/padv/padv_sf.gif?1314356941734

  24. Lonnie says:

    Awesome thunderstorm that just passed Albany, heading north! Lightning strikes were all around me and quite a few really close!

  25. THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A

    * SEVERE THUNDERSTORM WARNING FOR…
    EAST CENTRAL YAMHILL COUNTY IN NORTHWEST OREGON…
    EXTREME WEST CENTRAL CLACKAMAS COUNTY IN NORTHWEST OREGON…
    NORTHWESTERN MARION COUNTY IN NORTHWEST OREGON…
    SOUTHEASTERN WASHINGTON COUNTY IN NORTHWEST OREGON…

    * UNTIL 445 AM PDT.

    * AT 349 AM PDT…NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
    SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL…AND
    DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 11
    MILES SOUTH OF AURORA…OR 15 MILES NORTHEAST OF SALEM…AND MOVING
    NORTH AT 25 MPH.

    * OTHER LOCATIONS THE SEVERE THUNDERSTORM WILL BE NEAR INCLUDE…
    AURORA…
    NEWBERG…

  26. chiefWright says:

    Wind is still relatively light. That cell over Mt. Angel just sparked a HUGE one; not sure if it was CG or CC

  27. umpire says:

    In NE Salem at my sister’s house – lightning and thunder since at least 3:30, when the dog woke up, heavy rain for the past ten minutes. Storm seems to be moving off, at least for the t & l. Was non-stop lightning for a while!

  28. chiefWright says:

    And I’m just starting to see moonrise to the NE! Lightning frequency is diminishing.

  29. chiefWright says:

    This is bizzare- I’m seeing lightning all around now, NE-S-NW, and overhead. It’s black to the S towards Silverton. Just now light rain has started. I can see the strobe lights on the Abiqua radio tower reflecting off the cloud bottoms

  30. chiefWright says:

    radar suggests Silverton is getting pummled, and we’re going to be in a deluge any second now.

  31. chris s says:

    pretty loud thunder down here west salem as well as lightning off to the east and south. Getting some light rain as well. Once again a really bad forecast by the mets, although kudos to rod hill for talking about it. The rest kinda get a flunking grade. :-).

  32. chiefWright says:

    There’s some light wind (5 mph?) right now.

  33. Kyle From Silverton says:

    Which one of you started up this wild lightning and heavy rain?

  34. chiefWright says:

    This bad boy is lighting up all around me! Most of the discharge appears to be cloud-to-cloud, and it’s BIG!!!!

  35. Okay…. this storm is beginning to show some bow characteristic with it and I see indication of mid-level rotation…. Wind damage threat is probably increasing.

  36. THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A

    * SEVERE THUNDERSTORM WARNING FOR…
    EXTREME WEST CENTRAL CLACKAMAS COUNTY IN NORTHWEST OREGON…
    WEST CENTRAL MARION COUNTY IN NORTHWEST OREGON…

    * UNTIL 400 AM PDT.

    * AT 321 AM PDT…NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
    SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL…AND
    DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 6 MILES
    SOUTH OF SILVERTON…OR 11 MILES EAST OF SALEM…AND MOVING NORTH
    AT 30 MPH.

    * OTHER LOCATIONS THE SEVERE THUNDERSTORM WILL BE NEAR INCLUDE…
    SILVERTON…
    AURORA…

  37. Radar update: 70.0dbz. Hail core 1.44″, VIL 83.3. This is now a LEGIT Severe Thunderstorm.

  38. New info on the storm…. Hail mark now 1.25″ with a 76% chance of severe hail, and a VIL core has developed. There may actually be some dime to quarter sized hail now.

    My lights are flickering…. storm related?

  39. BULLETIN – EAS ACTIVATION REQUESTED
    SEVERE THUNDERSTORM WARNING
    NATIONAL WEATHER SERVICE PORTLAND OR
    307 AM PDT FRI AUG 26 2011

    THE NATIONAL WEATHER SERVICE IN PORTLAND HAS ISSUED A

    * SEVERE THUNDERSTORM WARNING FOR…
    CENTRAL MARION COUNTY IN NORTHWEST OREGON…
    NORTH CENTRAL LINN COUNTY IN WESTERN OREGON…

    * UNTIL 330 AM PDT.

    * AT 255 AM PDT…NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
    SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL…AND
    DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 7 MILES
    SOUTH OF STAYTON…OR 17 MILES EAST OF ALBANY…AND MOVING NORTH AT
    20 MPH.

    * OTHER LOCATIONS THE SEVERE THUNDERSTORM WILL BE NEAR INCLUDE…
    STAYTON…

  40. I have had quite a lightning show since about 2am. Nice surprise.

  41. BIG storm southeast of Salem just near Mill City. Up to 68dbz! It’s darn near trying to turn Severe.
    ZOOMED RADAR

    It’s really neat on the WV Loop if you zoom in further you can see the two distinct bands of storms and also what looks like an area of diffluence possibly. Also 500Mb chart indicates the flow should either remain southerly or possibly back slightly to SSE. http://www.spc.noaa.gov/exper/mesoanalysis/s11/500mb/500mb_sf.gif?1314352543343 See the wind barbs? Also temps aloft are SLOWLY cooling further…..

  42. It’s really need on the WV Loop if you zoom in further you can see the two distinct bands of storms and also what looks like an area of diffluence possibly. Also 500Mb chart indicates the flow should either remain southerly or possibly back slightly to SSE. http://www.spc.noaa.gov/exper/mesoanalysis/s11/500mb/500mb_sf.gif?1314352543343 See the wind barbs? Also temps aloft are SLOWLY cooling further…..

    GR2AE suggest tops are up to 36,400′ … Not bad guys.

  43. That weak ULL I discussed earlier with my analysis held together and is lifting northeast. Storms should move into PDX metro.

    WV Loop – 2KM (Zoomed)
    http://sat.wrh.noaa.gov/satellite/loopsat.php?wfo=pqr&area=west&type=wv&size=2
    There is a chance these continue to expand and maybe get a hair stronger.

    Looking at Mesoanalysis it appears that mid-level lapse rates steepened to around 7C/km, there is some instability above 700Mb, but lift is the main thing triggering these.
    http://www.spc.noaa.gov/exper/mesoanalysis/s11/vadv/vadv_sf.gif?1314352106606
    http://www.spc.noaa.gov/exper/mesoanalysis/s11/padv/padv_sf.gif?1314352141381
    Strong, compact lift and its heading right for the northern Willamette Valley.

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