Unusually Humid Heat Wave On The Way; Thunder Too

Our longest/hottest period of weather in 5 years begins this weekend and continues through at least the middle of next week.  The weather maps and models all scream “get an air conditioner if you don’t have one!” .

DETAILS

  • Temperatures warm today up to around 90 or so in the western valleys
  • Hotter temps are likely (somewhere between 90-100) for Saturday through Wednesday.  We haven’t seen a period like this since late July and early August 2009.
  • At this point it appears unlikely we’ll get above 100 degrees, but we might hit that century mark either Sunday or Monday.  I suppose the point of this statement is that as of now I don’t see one of those heatwaves with several days around 101-105.  But it’ll feel that hot because of the next point…
  • Very high relative humidity/dewpoint levels mean unusually warm nights and sticky weather.  And I wouldn’t be surprised if we have at least one 70+ degree lows in Portland; a first since the 2009 heat wave.
  • Thunderstorms are quite possible west of the Cascades during the period Sunday afternoon through early Monday morning.  They will add moisture to the air at the same time a very hot atmosphere is over us.

 

I’m still on vacation this week but figured I should chime in on the approaching hot weather.  In one word…yuck for those without air conditioning.  For meteorologists and weather geeks we have a good possibility of thunderstorm action (real summer storms, not the boring spring/fall ones), and some extreme temperatures.  So I’m a bit torn since I feel bad for those that are going to be real cranky, tired, and overheated by midweek.

Why so warm?  An upper-level ridge retrogresses from the Rockies to right over Nevada tomorrow and Sunday, then just offshore by the middle of next week.  500mb maps for Sunday ecm_sun_11am and again Wednesday ecm_wedVery high upper-level heights, but not a sharp ridge.  More of a smothering of warm/hot air.  Without sharp ridging we don’t get easterly flow/thermal trough over us for the extreme heat (103-107) and dry air.  But we also see the cooling effects of the Pacific Ocean reduced to almost nothing with very little onshore flow.  At some point later next week the ridging is centered far enough to the west that the airmass cools some and we get more onshore flow.

Why so humid?  Two reasons, first is that sea surface temperatures are running above average offshore along the north Oregon and Washington coastline, so dewpoints/humidity tends to be a few degrees/percent higher than normal this season anyway.  The 2nd is thunderstorm moisture coming up from the south.  You can already see it on satellite pictures this morning in southern Oregon;  it’ll work its way northward for the next 3 days.  Notice the midday Sunday map above shows an upper-level disturbance stuck on the west side of the ridge.  It’ll move over us later in the day and early Monday.  We’ll see how many thunderstorms it sets off.  Could be a nice outbreak of storms during that period or just a few.  But they will add moisture to the air.  Cloud cover off/on the next 3 days will keep nights toasty too.

Which day will be the hottest?  Tough call due to cloud cover at times.  I’m guessing it’ll be Sunday, Monday, or Tuesday.  ECMWF KPDX_2014071100_dx_240 has all of those days about the same but warmest Tuesday.  WRF-GFS says Monday after a very warm night Sunday night with cloud cover and a few thunderstorms keeping temps up.  Then skies clear out; perfect setup for a scorcher.  Our 00z RPM last night showed low-mid 100s Sunday with very weak offshore flow that day ahead of the approaching upper-level disturbance.  web_RPM_Text_00z_PDX But sometimes it is all out by itself (and wrong), so I don’t put too much faith into it.  Plus the new 12z only says 97 now with a lot more cloud cover.

July is looking to be a scorcher!  Stay cool…

Chief Meteorologist Mark Nelsen

 

 

 

91 Responses to Unusually Humid Heat Wave On The Way; Thunder Too

  1. chiefWright (Marquam) says:

    Pretty strong t-storm just passed thru. A couple of solid CG strikes within a mile. One strong shower, only about a minute, now light precip. Sky wasn’t terribly heavy, a the lightning seemed to come out of nowhere.

  2. cgavic says:

    Heavy rain, big drops have just now hit Sandy and its park.

  3. cgavic says:

    Thunderstorms have hit Sandy and its mountain festival. Huge gathering of home made unique gifts under the trees. Let’s pray for no lightning there. Tons of people there with over 100 vendors under 10 by 10 foot white canopies.

  4. Roman~Snow-Zone-Monmouth, Elv. 223' says:

    Lots of rain, lightning and thunder this morning down in these parts.

  5. alohabb says:

    Do we even hit 80 today?

  6. chiefWright (Marquam) says:

    Finally, the AFD is out. Someone needs to work on their spelling.

    AREA FORECAST DISCUSSION
    NATIONAL WEATHER SERVICE PORTLAND OR
    1027 AM PDT SUN JUL 13 2014

    CLOSELY ON THE HEALS THIS AFTERNOON WILL BE MORE OF THE SURFACE
    BASED CONVECTION AND THE GREATER CONCERN FOR STRONG STORMS.

  7. chiefWright (Marquam) says:

    Looks like a shower in the Hillsdale area? Bertha roadcam has wet pavement.

  8. chiefWright (Marquam) says:

    Well, NWS isn’t asleep this morning; they just issued a t-storm/hail alert. For Tillamoook. And no morning report yet. Maybe they’re on vacation like Mark. Guess the rest of us just need to GOLU. Which isn’t bad, on an interesting weather day like today.

    Still rumbling out there, but not as frequent. And getting a few sunbreaks.

  9. Taylor says:

    Mammatus clouds in Clackamas, OR sign of an unstable airmass. Getting exciting!

  10. alohabb says:

    LOTS OF LIGHTNING in Aloha! wow…

  11. chiefWright (Marquam) says:

    Incoming Albinos! Getting plenty of rumbles, and the lightning map is filling in. Plenty of nascent cells out there heading North. NWS bumped tstorm chance up to in the last hour, but I’m suprised they haven’t issued a special weather statement.

    • chiefWright (Marquam) says:

      Some precep associated with this. There’s been wet roadcams this morning at Santiam Pass, Detroit Lake, Enchanted Way, and I5 N of Eugene.

      Boomers are really picking up! Less than 1 per minute.

  12. alohabb says:

    BLACK skies moving into western washington county.

  13. runrain says:

    Wow. Here they come!

  14. schmit44 says:

    7/12/2014 Oregon (All) Temperature Summary

    Warmest:
    High:106 at DW0462 Umatilla( 390 ft)
    Low: 75 at BLALOK(277 ft) & EW4492 Holdman(1401 ft)

    Coldest:
    High:56 at YACHTS Yachats(82 ft)
    Low: 39 at Horse Ridge (US (4160 ft )

    Largest Diurnal Change: 54 degrees
    PRINEVILLE 4NW (101/47 ) (2839 ft )

    Heaviest Rainfall:
    0.12″ at MCDERMITT 26N(4464ft)
    0.12″ at RIDDLE MTN.(6352ft)

  15. Hal in Aims says:

    NWS must be flummoxed…….9:30 pm and no new discussion, etc…guess tonight and tomorrow will be GOLU……

  16. Lurkyloo says:

    I am officially tired, cranky, and overheated! 😦
    Hope your donkeys show up, Poose.
    Welcome home, Erik.
    Hi Rob!
    Happy camping Mark?
    Everyone else — stay cool!

  17. Looking for some convection up this way in W WA tomorrow. Looking like box from HIO-SHN-SEA-TTD will contain most active cells per 18z.

  18. paulbeugene says:

    18z high res NAM shows lack of convection tonight over western OR. Radar returns light up by noon over N OR cascades and N Coast range tomorrow with best convection in lowlands being PDX north

  19. pappoose in scappoose says:

    URGENT – WEATHER MESSAGE
    Heat Advisory:

    SCHEDULING FREQUENT REST BREAKS
    IN SHADED OR AIR CONDITIONED ENVIRONMENTS.

    • pappoose in scappoose says:

      Comment is awaiting moderation, can’t make a comment about the pres without a double check! (my only chance of creating a problem for the pres is consuming the beer before he can get a handle on it!)

  20. W7ENK says:

    Howdy! I’m back Stateside, returning to Portland tonight… right after the M’s A’s game, and just in time for the weather to get exciting?!? Or maybe a big ol’ bust?? I’m really hoping for the first option. 🙂

    Supercells sound like fun!

  21. Garron near Washington Square says:

    NEW CONVECTIVE OUTLOOK THIS MORNING…Looks like thunderstorm threat has shifted for tonight and early tomorrow, though there may be some more action if there is enough clearing tomorrow after the first batch tonight. Might also be cooler and muggier tomorrow.

    http://www.wrh.noaa.gov/forecasts/display_special_product_versions.php?sid=pqr&pil=afd

  22. Tyler Mode says:

    NW wind blowing this morning. Maybe today won’t be as hot as earlier expected. 57 for a low.

  23. Rob - Southeast Portland says:

    Latest SPC Convective Outlook for Sunday just got REAL interesting. A 5% Severe Risk for the Willamette Valley and Cascades continues, but they just added this in their 1 AM Discussion.

    DAY 2 CONVECTIVE OUTLOOK
    NWS STORM PREDICTION CENTER NORMAN OK
    0100 AM CDT SAT JUL 12 2014

    VALID 131200Z – 141200Z

    …OREGON…
    A COMPACT SHORTWAVE TROUGH AND ASSOCIATED 40-50KT MID-LEVEL WIND MAX WILL SPREAD NORTHEAST ACROSS OREGON DURING THE DAY. LIFT AND SHEAR WITH THIS IMPULSE MAY BE SUFFICIENT FOR A FEW HIGH-BASED STORMS AND PERHAPS A SUPERCELL WITH HAIL AND STRONG TO ISOLATED DAMAGING WINDS POSSIBLE.

    Supercells? Why not.

  24. schmit44 says:

    7/11/2014 Oregon (All) Temperature Summary

    Warmest:
    High:102 at JOHN DAY RIVER A( 400 ft) & ALKALI FLAT(2495 ft) & LAKE OWHEE AND O(2400 ft) & ONTARIO(2260 ft)
    Low: 72 at ALKALI FLAT(2495 ft) & Ontario Municipa(2188 ft)

    Coldest:
    High:54 at Newport(30 ft)
    Low: 37 at CLACKAMAS LAKE (3400 ft )

    Largest Diurnal Change: 52 degrees
    EW2055 Prairie C (95/43 ) (3547 ft )

    Heaviest Rainfall:
    0.45″ at DW6983 Winston(600ft)
    0.19″ at HYATT DAM AND RE(5013ft)

  25. Boydo3 N. Albany says:

    Amazing evening out tonight. The longest, most colorful sunset for this area in a long time. Just went on and on! Then the moon busts through the departing clouds…stunning!!! Now just a great big moon and stars!

  26. flurball says:

    Look at the NWS posting a Sweat index number. Is that calibrated to the OJ trial? If the sweat drips you must predict?

  27. Rob - Southeast Portland says:

    Model: 21z SREF
    Valid: 7/13 – 7/14
    Timing: Sunday 3 – 9 PM(Elevated storms, some strong are also likely overnight into Monday AM)

    SBCAPE 2500-3000J/kg, MLCAPE 2500-2750J/kg, MUCAPE 2500-3000J/kg, LI -9 to -10, Supercell Composite 6, Effective Shear 40kts, 0-6 KM Shear 40kts, 0-1KM Helicity 50-100m2/s2, 0-3KM Helicity 150-200m2/s2, Dewpoint 66-70, PWAT 1.25″ to 1.45″, 24HR T-Storm Probability 30%(Increasing to 35% overnight Sunday into Monday AM), Severe T-Storm Probability 5-10%(Increasing to 10-15% overnight Sunday into Monday AM)

    *Most noticeably on this run would be the increase in Shear, Supercell composite, and MLCAPE values a bit higher. IF everything works out right and if 40kts shear verifies on Mesoanalysis on Sunday afternoon that could support Severe thunderstorms perhaps some organized too. I hope future runs continue this theme. There could be some exciting times ahead.

  28. High Desert Mat says:

    Not too sure about your new weather graphics Mark. I feel like I’m in 2nd grade again. Lol.

    • High Desert Mat says:

      And why are some of the suns more orange or yellow than the others when the temp is practically the same?

  29. JohnD says:

    Thanks, Mark, for your detailed summary!
    Fun stuff!
    As always, you rock!
    John D.

  30. Sifton says:

    Happy Heatwave everyone!!!

  31. alohabb says:

    Ok,,burn PILES went out of control starting a major brush fire in rural Hillsboro….who would think this is a good time for a burn pile!!!!

  32. james says:

    God I’m dreading this heat wave… I live near dt and my apartments won’t allow air condtioners… time to sit dripping wet in my birthday suit in front of the fan! If this is any indication, than this is found to be a miserable summer

  33. umpire says:

    In any case, hot, hot, hot, and I have softball games to umpire both Saturday and Sunday during the day – better order up that five-gallon drum of sunscreen;) And, those cold adult beverages will taste mai-tai-fine in the evening!

    FYI, if anyone is still looking for a fan or a/c unit, Parkrose Hardware had quite a few earlier this afternoon.

  34. alohabb says:

    I love the heat! Great for business!!!! A/C business booked out for weeks!!!! Service as well!!! Power outages helped as well

  35. Rob - Southeast Portland says:

    Mark, excellent post, thanks.

    I am loving the SREF output. Consecutive runs spitting out CAPE values 2500-3500J/kg and Lifted Indices of -7 to -9(unheard of for us) Sunday afternoon through Monday 9 AM is looking possibly very exciting. Theta-E environment looks excellent. Possibility for even some Severe warnings even west of the Cascades as shear increases to 30-35kts.

  36. pappoose in scappoose says:

    If you don’t like this view, you don’t like interesting weather!

    http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?vis1km_west_full+6

    • Rob - Southeast Portland says:

      WHAT DOES IT MEAN!

    • pappoose in scappoose says:

      It means we’re gonna have some FUN!

    • pappoose in scappoose says:

      Hot off the press:

      SUNDAY LOOKS TO BE QUITE INTERESTING. ANOTHER ROUND OF MOIST SOUTH
      FLOW ALOFT BEGINS TO SPREAD INTO SWRN OREGON AS EARLY AS SAT EVENING.
      GFS AND ECMWF SIMILAR WITH THE OVERALL DETAILS…BUT THE 12Z NAM
      APPEARS TO BE AN OUTLIER. THE 12Z ECMWF AND 12Z GFS BRING THE NEXT
      LOW CENTER TO NEAR 41N 129W BY 12Z SUN. THE NAM IS A LITTLE MORE SW
      WITH THE FEATURE AND MUCH SLOWER MOVING IT THROUGH THE FORECAST AREA.
      UNLIKE TODAYS SYSTEM…THIS NEXT ONE IS EXPECTED TO
      HAVE JET SUPPORT. GFS AND ECMWF SHOW A 60-80 KT 300 MB JET SEGMENT
      MOVING INTO SWRN OREGON SUN MORNING. FORECAST AREA WILL BE IN THE
      FAVORED QUADRANT OF THE JET SEGMENT FOR ADDITIONAL CONVECTIVE
      SUPPORT. GFS MODEL SOUNDINGS FOR KPDX AND FOR A POINT IN THE N OREGON
      CASCADES VALID SUN AFTERNOON ARE QUITE IMPRESSIVE. THE KPDX SOUNDING
      VALID 00Z MON HAS A SURFACE-BASED CAPE OF NEARLY 600 J/KG…LIFTED INDEX OF -2…TOTAL TOTALS OF 51 AND PRECIPITABLE WATER OF 1.37
      INCHES. THE CASCADE SOUNDING IS EVEN MORE IMPRESSIVE WITH A CAPE OF
      OVER 900 J/KG…LI OF -4…TOTAL TOTALS OF 54…0-6KM BULK SHEAR OF NEARLY 40 KT…PRECIPITABLE WATER 1.66 INCHES…AND A SWEAT INDEX OF
      311 (WE USE 250 AS THE BENCHMARK FOR POSSIBLE SEVERE). THE SREF CALIBRATED PROBABILITY OF THUNDERSTORMS VALID 00Z-03Z MON SHOWS A 50
      PERCENT BULLS-EYE OVER THE CASCADES AND THE 30 PERCENT CONTOUR TO THE
      COAST. ALL IN ALL…MODELS ARE SHOWING SEVERAL INGREDIENTS COMING TOGETHER FOR A CLASSIC PAC NW THUNDERSTORM EVENT. THUNDERSTORM
      ACTIVITY SHOULD CONTINUE THROUGH SUN NIGHT…ESPECIALLY IN THE NERN ZONES.

  37. vinnybob says:

    At noon only 70 in Medford with light rain.

  38. EY (Oak Grove) says:

    I decided to do a bit of catching up and saw this post from July 2nd that caught my eye…

    paulbeugene says:
    July 2, 2014 at 10:39 pm
    It is a ways away…July 12 (9-10 days away)…but the models have it looking like a decent convective outbreak for Oregon, especially SW Oregon and the Cascades and points eastward, as is usually the case. Some convection over Willamette Valley also possible. Both the GFS and Euro runs are showing this, with 500mb height falls setting up offshore of northern California, great basin 500mb ridge inland.

    I know it was a shot-in-the-dark prediction, but man did the models actually do decent at that point!

  39. Jeff says:

    The idea that a person will endure unbearable suffering without an air conditioner is ludicrous. We are becoming a society of pampered crybabies.

  40. Joshua says:

    Thunderstorms are the only thing that can salvage this horrific and abominable forecast. There can’t be too many places on Earth with worse upcoming weather.

    • pedro771 says:

      Uhhh, there are plenty of places on earth that will have worse weather then this.

      Stop being so dramatic.

    • Aloha Rainshadow says:

      This is nothing…go live in the south with oppressive heat and humidity for 6 months…

    • EY (Oak Grove) says:

      I will say that he has one point, sorta… It’s that we don’t often see temps and humidity like this and yes, unless we hit 100 (which could bring near record Heat Index) and/or we get thunderstorms, it’ll just be a miserable week… And no, I don’t consider record overnight temps as a good accomplishment.

      But there are PLENTY of other places on Earth with worse weather, far worse; places getting hit by massive thunderstorms, straight heat, incredible humidity, any place getting hit by a tropical system and even for cold lovers, Antarctica has GOT to be a bit too chilly.

    • pappoose in scappoose says:

      I’d really like a salvage of that type!

  41. pappoose in scappoose says:

    Thunderstorms are quite possible! YES!
    I really like it when the weather gets INTERESTING!!

    SUNDAY CONTINUES TO LOOK MORE AND MORE INTERESTING. ANOTHER ROUND OF MOIST SOUTH FLOW ALOFT BEGINS TO SPREAD INTO SWRN OREGON AS EARLY AS
    SAT EVENING. MODELS STARTING TO CONVERGE ON A GENERAL SOLUTION. THE 12Z NAM…00Z ECMWF AND 06Z GFS BRING THE NEXT LOW CENTER TO NEAR 41N
    129W BY 12Z SUN. UNLIKE TODAYS SYSTEM…THIS NEXT ONE IS EXPECTED TO HAVE JET SUPPORT. NAM AND ECMWF SHOW A 60-80 KT 300 MB JET SEGMENT
    MOVING INTO SWRN OREGON SUN MORNING. FORECAST AREA WILL BE IN THE FAVORED QUADRANT OF THE JET SEGMENT FOR ADDITIONAL CONVECTIVE SUPPORT. NAM MODEL SOUNDINGS FOR KPDX VALID SUN AFTERNOON ARE QUITE
    IMPRESSIVE. BY 23Z THE MODEL SOUNDING SHOWS OVER 1500 J/KG CAPE…LI OF -3 AND AN EQUILIBRIUM LEVEL IN EXCESS OF 37000 FEET. STORM PREDICTION CENTER (SPC) EVEN MENTIONS THE POSSIBILITY OF A FEW STORMS
    APPROACHING SEVERE LIMITS. NAM MODEL SOUNDINGS FOR THE CASCADES ARE EVEN MORE IMPRESSIVE…WITH TOTAL TOTALS IN EXCESS OF 50…SWEAT
    INDEX OVER 250 (THE NORMAL BENCHMARK WE USE FOR POSSIBLE SEVERE WEATHER) AND 0-6KM BULK SHEAR VALUES OF 30-35 KTS. THUNDERSTORM
    ACTIVITY SHOULD CONTINUE THROUGH SUN NIGHT…ESPECIALLY IN THE NERN ZONES.

    • pappoose in scappoose says:

      DAY 3 CONVECTIVE OUTLOOK
      NWS STORM PREDICTION CENTER

      …NORTHWEST…
      STRONG HEATING OF THE NORTHERN PERIPHERY OF MONSOON MOISTURE PLUME
      AND ASCENT ASSOCIATED WITH A PACIFIC SHORTWAVE TROUGH MOVING INLAND
      COULD RESULT IN SCATTERED STRONG TO A FEW SEVERE STORMS ACROSS PARTS
      OF OREGON DURING THE DAY/EVENING.

  42. Garron near Washington Square says:

    I’ll be in Las Vegas thru Thursday, so I can “Garron-tee” there will be epic thunderstorms on Sunday, followed by the highest overnight lows ever recorded, and maybe a record high or two….Enjoy for me! I’m still hoping the desert sw will yield a few juicy thunderstorms while I’m down there like a few years ago when I was visiting in August. Thanks for the update Mark, and stay safe if you’re out camping in this stuff!

  43. schmit44 says:

    I am pumped for the heat event. Been 5 years and its time.

  44. paulbeugene says:

    Sunday PM on the NAM is a CLASSIC thunderstorm pattern. T storms develop over SW OR-Bend-Kfalls triangle and then arc outward to the NW and N. Salem and PDX would be in for potentially memorable lightning display in the evening (could be late evening in PDX for dramatic late evening/nocturnal lightning photo ops).

    thunderstorms would then progress N to Olympia/Tacoma etc

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