Posted at 9:17 AM on July 18, 2012
by Paul Huttner
69 degrees sticky, almost tropical dew points in the metro today
55 degrees comfy dew points today in International Falls & along the North Shore
Rain & Thunder - Scattered "hit or miss" T-Storms roaming Minnesota today
Latest Twin Cities radar loop
60s & 70s - Temps may not climb out of the 70s today in much of Minnesota!
2-day respite from brutal heat & humidity levels today & most of Thursday
Heat returns by Friday into this weekend
97 degrees NAM model forecast high temp Friday at MSP
70s dew points - tropical, even oppressive dew points this weekend
Cooling rain & thunder possible at times this weekend
Heat wave breaks: GFS & Euro models favor much cooler air late next week
High in the 70s for the metro by next Thursday & Friday?
Scattered rain & thunder today:
A weak low pressure system in the upper atmosphere sliding slowly east over Minnesota today is sparking scattered "cooling" showers & T-Storms.
Most of the storms should stay below severe limits today, but a few isolated severe storms may pack local downpours, small hail and some gusty winds.
SPC has placed a "slight risk" for southern MN today.
Thursday will feature more sun and highs should stay in the mid 80s, but sticky dew points in the upper 60s will make it feel a little "close."
Weekend Forecast: "Free Sauna" returns
It's still July, and even though our weak cool front is bringing some relief through tomorrow...hot steamy air is never far away this time of year.
The "return flow" from the south Friday and this weekend will bring more heat to Minnesota, and this time dew points in the 70s...to possibly an Amazon Jungle-like 80 degrees... will make it feel like an unbearable sauna out there at times.
The NAM model is doing a pretty good job of tracking the heat these days. Today's NAM is putting out 97 degrees for a forecast high temp on Friday with a sticky dew point of 65 degrees.
The GFS has been woefully underestimating temps this summer, but has been overestimating dew points. The GFS is putting out some downright scary dew point numbers of around 78 degrees by Friday and near 80 degrees this weekend. That's probably too high...but not out of the question.
Any way you look at it, with temps back into the mid-90s and dew points a few degrees either side of 70, this is going to be one hot, steamy weekend for Minnesota. This could be the "most humid" weekend of summer.
Wild Card: Scattered thunder & "convective debris?"
One wild card to the weekend heat wave could be the presence of scattered T-Storms. It's starting to look like we'll have a few rounds of scattered storms, and that may mean a cooling T-Storm and some convective "debris clouds" at times to limit sunshine and keep things a bit cooler.
Right now the best chance for a cooling T-Storm in southern Minnesota appears to be Sunday.
Relief late next week: Heat wave breaks?
There are still strong signs that a major change in the upper air pattern to a "northwest flow" will bring a significant break to the brutally persistent heat wave in Minnesota and most of the eastern USA late next week.
The GFS and Euro are hitting this trend, and the GFS is bringing down a much cooler & drier Canadian air mass late next week.
The eventual magnitude of the cooling is still a little in the air, but the numbers coming out of the last 3 days of GFS runs indicate highs in the (possibly lower) 70s and lows in the 50s (even upper 40s??) in the metro by next Thursday into the weekend of July 28th!
That's a good 20 degrees cooler than where we've been, and it may mean an extended break from the chorus of AC units Minnesota.
Stay tuned...it looks like the heat wave may be about to break late next week.
Now if I can just find an ice arena to hang out in this weekend.