Record Temps Today; More Heat Tomorrow

June 26, 2015

11pm Friday…

Portland hit 95 today, but that was one of the “cooler” metro area temps:

PLOT_Highs_Metro

Salem hit 100 and you can check out the triple-digit heat east of the Cascades and in Southern Oregon!

MarkRain_WaterYearPDX

It’s been a crazy June, the warmest we’ve seen since PDX became the official Portland observation site around 1940.  It’s also likely the warmest we’ve seen since record-keeping began downtown just 10 years after the Civil War!

Some more records…today was the 6th day at/above 90 degrees here, which ties the June record.  We’ll break it tomorrow.

MarkHeatWave_HottestDaysSoFar

Due to the very hot and extremely dry conditions, Multnomah County has taken the unprecedented step of banning all open flames…INCLUDING FIREWORKS until further notice.  Luckily that’ll save me some money and it’ll be

Thunderstorms did develop as expected in the central/southern Cascades and they lasted long enough for one strike up around Detroit.  They are done now but expect another round tomorrow afternoon/evening farther north.  We MIGHT see some lightning to our east this time Saturday evening.

Still a chance for a thunderstorm through the day Sunday, then increasing onshore flow plus best dynamics shifting the action north and east mean we’re done with that threat.

Once we get past a scorcher tomorrow (slightly warmer with light wind), a good marine push plus lots of high/mid clouds Sunday means at least a 10 degree drop in high temps.

Temps stay reasonable Monday-Tuesday…in the mid-upper 80s, then a 2nd heat wave arrives Wednesday through the 4th of July.

How hot is “Round 2” going to be later next week?  Morning models were real scorchers with easterly wind likely pushing temperatures to around 100 again over Independence Day weekend.  00z GFS not quite as crazy, but it’s pretty clear we have a 2nd heatwave as we head into the the 4th of July holiday weekend.

Stay cool this weekend!

Chief Meteorologist Mark Nelsen


A Scorcher Today; Turning Humid With Some Smoke Too

June 26, 2015

9am Friday…

Temperatures will approach 100 degrees this afternoon in the metro area as everything appears to be in place for a 4-7 degree warm up from Thursday’s temperatures.  We were 91-94 in the metro area Thursday, so that puts us in the 95-100 degree range by 4-6pm.

Weather Geek talk follows…

1. 850mb temperature was 21 deg (C) on the morning sounding over Salem, headed for around +24 this afternoon.  If we had easterly wind all the way down to sea level (through the Gorge), this atmosphere would allow a high temperature 100-104 in P-Town.

2. Onshore flow is weaker through the Gorge and winds have turned offshore above the surface.  Yesterday it was 1-2 millibars, right now only 0.7 between PDX-DLS.  West wind has pretty much shut down at the surface now east of the Coast Range.  Up above, sounding shows northeasterly wind all the way up to around 6,000′.  Onshore flow is SLIGHTLY stronger up the Columbia River this morning; that accounts for the high dewpoints (near 60) and humid feel to the air.  I have a feeling some of that will “mix out” this afternoon since it’s such a shallow layer.  Still, dewpoints will likely remain in the 55-60 degree range all day, slightly humid for our area.  We’ll see if they jump this evening.

3. Skies are totally sunny, except for some smoke approaching from the south.  Fires in Southern California and near Lake Tahoe have put a layer of smoke into the atmosphere (way up) and it has made its way into the southern half of Oregon.  The southerly wind higher up around 8,000′ and above will push that farther north.  Might be a nice reddish sunset tonight.  My guess is that we’ll need to get used to fire smoke much of the rest of the summer with big fires already burning in Alaska, Western Canada, & here in the USA West.

4.  Temps are running warmer in the hills already at 9am.  Wanderer’s Peak SE of Estacada (at 4,400′) is already 80 at 9am!  It was 68 at the same time yesterday.

Looking ahead, we’re still on for a good marine push Sunday night and Monday, with an upper-level disturbance depressing the ridge significantly the atmosphere cools quite a bit.  Thus the 80s for Monday and (we’ll see) Tuesday.  Then the ridge pops back the 2nd half of next week.  You can see it in the ECMWF ensemble chart; follow the red line:

tseries_850t_000-360_Portland

You see the dip Monday/Tuesday, then the rise through the 4th of July weekend, then FINALLY a drop to just a bit above normal the week after the 4th.

There is disagreement among models with respect to details for the big holiday weekend.  It will definitely be very warm, that’s not an issue, but at times models have been showing a shot of cool air into Montana and its associated high pressure allowing a thermal trough to develop west of the Cascades.  That is a classic extreme heat situation.  A bunch of our 100+ days have occurred in a scenario like this in the past.  So part of the 3 day period (Friday-Sunday the 3rd-5th) could be scorching hot OR it may just be 85-90 degrees with weak onshore flow.   The 12z GFS and last night’s ECMWF show the first scenario.

Main message here is that unusually warm weather continues for at least another 10 days.

Chief Meteorologist Mark Nelsen