Updraft

Updraft: July 26, 2010 Archive

< July 24, 2010 | Main | July 27, 2010 >

Dog Days: Steamy & stormy

Posted at 8:30 AM on July 26, 2010 by Paul Huttner (1 Comments)
Filed under: Climate, Heat, Severe weather

Welcome to July in Minnesota.

We complain all year that it's too cold, too windy, too this, too that. Here it is. You want 80? Gotcha covered. You want humidity? Can do. Sweltering 90s and big boomers? On the way.

I remember when we were kids (a loooong time ago!) in Minnesota and in January somebody would always say; "Boy I wish it was hot like July for just one day!" Then in July....we'd wish it was like fall again.

It looks like many weather wishes and fantasies will come true this week. We'll see perfect summer days, stifling heat and humidity, big storms and a cool almost "fallish" breeze by mid-week.

Here's the outlook:

Monday: Summer's finest. Mostly sunny warm and increasingly humid. Dew points climbing through the 60s. Spotty thunderstorms far west. Highs near 88 metro, 80 far north. Wind S 5-15 mph.

1 a a a mn.png

Tuesday: Uncomfortably hot & humid! Highs 94 to 97 south, including the metro. Dew points near 70. Strong to severe T-Storms moving north (AM & daytime) to south (late PM & evening). Wind south 10-20 mph.

Wednesday & Thursday:

Really nice! Noticeable drop in humidity with dew points falling into the upper 50s. Highs near 80 south, 70s north. Wind NW 10-20mph Wednesday, 5-10mph Thursday.

Friday into the weekend: Muggy again with increasing chances for thunder. Highs in the 80s.

July 2010: Warm again

July temperatures are running 3.4 degrees above average as we enter the last week of the month. This is the 5th straight month of above average temps in Minnesota this year.

We've had 4 days at or above 90 degrees this month, with a total of 7 days this year of 90-plus. The average number of 90 degree days for the summer is about 13 days.

One day heat wave:

Day #8 of 90 degree weather will occur Tuesday as heat and humidity will surges north ahead of an advancing cold front. Some forecasting techniques yield a high temperature of between 95 and 97 degrees Tuesday from the metro south. Dew points will approach 70, so you'll feel like you're swimming in a free sauna. Heat indices should climb above 100 Tuesday.

Severe threat:

As the cold front pushes south Tuesday, severe storms will again rumble across the state. Unlike the last few outbreaks, these storms will come from the northwest and work south.

SPC has a slight risk for storms in Minnesota. It looks like storms will fire in northern Minnesota during the day, and rumble into the southern half of the state later in the afternoon and evening. The primary threats will be damaging wind and hail, but there could be a few tornadoes as the storms get going Tuesday PM.

1 a a a spc.jpg

1 a a a day 2.jpg

Enjoy the last week of July!

PH

(1 Comments)

Forecast: Tuesday heat and severe threat

Posted at 4:26 PM on July 26, 2010 by Paul Huttner
Filed under: Heat, Severe weather

Get ready for a wild weather Tuesday.

Tuesday will feature excessive heat in much of southern Minnesota, and the threat for strong to potentially severe thunderstorms statewide.

Let's start with the heat.

A hot, sticky air mass is surging north from Nebraska and Kansas. Temperatures reached the mid to upper 90s from Kansas into the Dakotas and eastern Montana Monday. The "thermal ridge" or heat core is likely to shift east and be in place right over southern Minnesota during the day Tuesday.

1 a a a tmp.jpg
(Click for bigger image)

One forecast technique yields high temperatures between 95 and 100 degrees in southern Minnesota, including the Twin Cities Tuesday!

I expect many locations will hit 94 to 96 Tuesday, and I wouldn't be shocked to see a 100 degree reading somewhere in the southern half of Minnesota Tuesday around 5pm.

It's the heat AND the humidity!

The one day heat wave will come with dangerous humidity levels. Dew points will surge toward 70 degrees.

1 a a a dewps.jpg

Some of the models hint at dewpoints approaching 75 degrees by Tuesday evening in the metro! That's Amazon Jungle humidity folks. We generally feel that level of moisture in Minnesota only once or twice a year.

1 a a dewps 70.jpg
Forecast modles push dew points into the oppressive 70s Tuesday. Note the delightful drop into the 50s by mid week!

We could see some areas hit what I call the 95/75 danger zone. That's a temperature of 95 degrees with dew point of 75. That yields an oppressive heat index of 107 degrees. Minnesotans (or anybody else for that matter) are generally not equipped to cope with that intense level of heat and humidity. 95/75 is a rare combination in Minnesota.

Take care tomorrow as temperatures and humidity rise to rain forest levels.

Severe threat:

A Canadian cold front will bring welcome relief with cooler temps and much lower humidity by Wednesday. It will also be the trigger for strong to severe storms as it slices through the steamy unstable air mass over Minnesota Tuesday.

1 a a a mn.png

Storms will favor the northern half of Minnesota during the day Tuesday, and then spread south into southern Minnesota Tuesday evening and overnight. I'll be scanning new forecast model runs overnight to update timing, but right now looks like the highest probability window for severe storms in the metro will be between 7pm Tuesday evening and 1am Wednesday morning.

The potential is there for large "bow echoes" to develop Tuesday in Minnesota. These lines of storms can cause widespread straight line wind damage. Also, several factors are coming together to spawn a few big rotating supercell thunderstorms at the onset of Tuesday's outbreak. The combination of heat, moisture and directional wind shear (winds verring from south to WNW with height) may cause storms to rotate. These storms have the potential to produce (hopefully only a few) tornadoes.

SPC has "risked" much of Minnesota Tuesday. Be alert for severe weather watches and warnings as the storms approach.

1 a a a outlook.jpg

1 a a a percent.jpg

Stay cool and keep an eye out for storms Tuesday!

PH

July 2010
S M T W T F S
        1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31


Master Archive

Recent Entries

MPR News
Radio

Listen Now

On Air

Weekend Edition Saturday®

Schedule

Shortcuts
Hourly Newscast
Hosts
Station Map

Other Radio Streams from MPR

Classical MPR
Radio Heartland

Services

Become a sponsor