This rainfall is not nearly enough to offset the extended dry period we've been seeing over the last few weeks, but it hopefully will be enough to keep the dust down a bit better and reduce some of the fire weather conditions to the point where the Fourth of July will be a relatively safe holiday. No statewide fireworks bans are anticipated at this time. As always, check with your local county sheriff as to which days it is safe and lawful to set off fireworks.
The other part of the good news may be what's to come; our ridiculously dry June may give way to a more normal first few weeks of July. I warn you straight away - for this prediction, I'm turning to the models, and we know how those have been over the past month. However, I do believe that there's only so many times you can roll snake eyes before you HAVE to get something else, and more than a few model runs have been suggesting some decent thunderstorm potential over the coming week to two weeks.
There's a bit of back-and-forth regarding the mid-to-upper level winds and the east/west position of an upper-level trough in the last couple of GFS runs. This could have a big impact on where storms first fire up and what their upper level support will be, but it looks like low level and surface conditions will begin to become ripe for thunderstorm development in the Great Lakes region starting next Thursday. Temperatures should soar into the upper 80s and low 90s. Thursday has nothing on Friday, though; upper 90s to even 100°F are being forecast for Friday, July 8th. Dewpoints are forecast to be nothing short of oppressive to the tune of 75° - even if we come out on the low end of this forecast, we're going to have low-to-mid 90s with 70° dewpoints. This should send heat indexes into dangerous territories which we haven't seen in a few years. A real risk of heat-related injuries may be present throughout Michigan on Friday. To give you some idea of what we could be looking at, the calculated heat index of the worst case scenario being put forth by this model (temperature of 100°, dewpoint of 76°) equates to 115°. Stay close to areas with air conditioning next week.
All of this heat should produce a ridiculous amount of instability in the atmosphere. The question now is going to be what kind of capping and forcing for ascent will come along with it. The latest GFS has the cap eroding by Friday over Wisconsin. This could lead to widespread thunderstorm development and a potential MCS (widespread linear/semi-linear storm system) moving into Michigan overnight Friday into Saturday, if the position of a cold front cooperates. The GFS has a warm front moving into the area Friday and a cold front not far behind it, so this could easily happen. Storms could also develop along the warm front, though again, this is going to depend heavily on how much capping is in place at the low levels of the atmosphere. This model is also hinting that low level wind speed should be quite strong - 40-50kts. Mid level winds are a bit more tame, so bulk shear values are coming in around the same, but with mid-level winds that strong any storms should have a chance to be more organized.
From what I can see, the latest ECMWF is mostly in agreement with the GFS, although its range is somewhat limited at this point. More will be shown in subsequent runs. Rumblings from NWS Detroit seem to also indicate better chances for thunderstorms in the coming week. The latest forecast discussion expressly mentions a better chance for scattered convection. The SPC also specifically mentions a severe risk in the upper Great Lakes during the day 5-7 period, though predictability concerns preclude any highlighted areas.
The forecast definitely looks better than it did a week ago, and hopefully this morning's rain will reduce some of the allergy misery. THAT, at least, can't get any worse!
No comments:
Post a Comment