lakeville weather journal

The grass is getting green and long...the question is whether or not I will find any "dry time" to cut it anytime soon. Lakeville has now seen just over 1.3" of rain since the current system moved in on Friday. Everything the models have predicted has happened. The "closed low" is now moving north toward MN from just west of Des Moines, IA. The following surface map depiction illustrates the classic "cylconic" image of the low in true form:

Notice the "wind barbs" - those lines drawn out from each city that have little barbs on them indictating wind direction and speed. If you look at the "big picture" the image should be the obvious shape of a cyclone. The wind spirals around the center, which is in west-central IA right now.

In any case, all indications are that this low will slowly drift towards Lakeville over the next 12-24 hours. As the center moves towards us, winds will subside and shift to the south again, then from west, then the northwest as the low heads upstate. With the shift, and depending on any easterly drift to the system, we will have yet another pronounced, and prolonged period of rain tonight into Monday. I am more optomistic in thinking that the system will match up with the NAM model and move to Northern MN by Monday night, and we can expect to get a reprive from the rain until sometime Tuesday evening...this is when the models paint a sudden burst of warm air surging through the mid levels to fuel the possibility of thunderstorms late in the day Tuesday.

For the remainder of today - rain rain rain. And tomorrow rain rain rain. Your best chances for any "breaks" in the steady nature of the showers will be between noon and 1600 local Sunday.

Posted by pierre at 9:55 AM | Permalink

75 didn't happen yesterday...oh well. What gets me is that we missed it by ONE DEGREE. Yesterday was nice, all things considered. Today...as predicted...not so nice. The rain was desparately needed, but it isn't going to leave anytime soon.

As I discussed last night, the trough did get to that line from Devils Lake to Huron, but not until about 7AM. So, I was a little too eager...the bad news is that my prediction of the stall out did occur. The trough is parked about Watertown, SD now, with the lowest central pressure somewhere between Huron and Watertown. This is also where the jet noses in per earlier models, and convection is greatest here as a result. Sure enough, at the time there are some severe thunderstorm echos on the ABR WSR-88D radar:

I drew in the center of the low and the associated trough (brown dashed line), and an arrow pointing at the area of storms. These cells may be carrying small hail, and have some strong winds associated with them. But as you can see, the rest of the precip is really tame on the convective side. But the atmosphere is plumb with moisture. The system will continue to tap moisture from two sources: Pacific moisture carried from a southern low that moved from the desert SW into the Texas panhandle. This system will start to tap Gulf moisture, and ride up a strong southerly flow in the mid-level winds. The Texan low will basically "merge" with the Dakotan low and park over Iowa for the weekend.

The parking of the system is typical of a "cutoff low" - and this was a feature predicted to visit earlier in the week, but it never transpired. Cutoff lows or "closed" lows do not get carried along with the upper winds, and here again, the models have predicted the jet stream to "split" around our rainmaker, leaving it parked over the IA cornfields. The main "polar jet" is going to hang out in nothern Manitoba, and a southern branch or "sub tropic" jet will continue to stream along the southern US. (This is the same jet that has been the "conveyor belt" for southern storms this spring - and it should continue through early next week.)

Longer range models show the low will spin out of IA by late Tuesday (ugh)...this means we are expecting rain showers, and maybe a few rumbles of thunder here and there through Monday for sure. Weekend rain totals could push two inches, with some forecasters thinking Sunday will see the most rain. I have not studied the precip "amount" potentials, but I can confidently say that we have a 100% chance of rain thru the weekend.

Posted by pierre at 6:41 PM | Permalink

I have been waiting patiently for the temps this week to get above 70, and push 75. Today might be the day...high pressure continues to dominate. Winds are finally shifting to the south, and the air is still extremely dry. So dry in fact that Red Flag Warnings continue for parts of east-central MN. Fire weather for Lakeville is in a lower "danger" rank, but fine-fuel moisture is at its lowest since the thaw (pushing a 90 rating now - very dry). Temp-wise, I am sticking to my guns, and I think 75 is a good possibility.

Moisture is in the cards, however, and the biggest question in the short term is timing. Right now, a low pressure trough has swung out of Alberta and is now digging deeper across the Dakotas. By the time the new models this afternoon come out, the timing and placement of any convective activity (t-storms) and continued shower events should become more evident.

For now, my guess is that the frontogenesis will be well defined along a Devils Lake-Jamestown-Aberdeen-Huron line in the Dakotas by late this evening (lets say 2100 CDT). This puts my guess a little ahead of the NWS prognositcators. My reasoning is this: in looking at 800MB winds (wind at around 6000 feet), the southerly flow is going to pick up dramatically over the next 24 hours. Then an accompanying jet up at 18000 feet digs in behind the surface front in the Friday AM hours. My take is that the southerly advection will fuel moisture adequately, but lift and instability will depend on the timing. IF the front slows up a little after midnight tonight, I can see some AM thunder here. After that, showers and a prolonged rain event will depend on upper winds post-noon Friday.

Enjoy today: 0730 temp was 50, its 70 now at 1230...let's see, 20 degree increase over 5 hrs, so that's 4 degrees per hour...let's say 2-3 more heating hours to go...at this rate, we will hit 78??? :)

Posted by pierre at 12:30 PM | Permalink

Looks like we will not (*knock on wood*) hit the freezing point tonight as threatened by many AM forecasters today. CFP (cold front passage) was on the mark, just after noontime, and temps modified in kind along with dedication of wind field to a northerly direction (shifting from west). After sundown, however, not much rate of change for temps. I will say we hit 35 tops as the low...time will tell. Precip is staying south of metro, and I am not confident we will see much here...maybe a sprinkle thru midnight.

Longer term shows that Canuck high camping out in the Great Plains for the balance of the week. Things will dry out everywhere (in fact, most moisture here today is being pulled south by low pressure in the Ozarks.) We saw a similar high pressure dominance a couple weeks ago when we had tems in mid-80's. If winds settle down, we could see a repeat in my opinion. Most forecasts and models are holding to 70 as daily highs with pure unabated sunshine for the duration. I am willing to bet 77 by Thursday. By Friday and Saturday, predicted troughing of the jet will give us chances of precip, but too far out to tell if thunder threat will be present.

Posted by pierre at 9:07 PM | Permalink

Well, we didn't quite get the 72 I was hoping for today....well with rounding we get 72 (71.5 was the official high here at lakevilleweather.com). However, the weekend was excellent weather-wise. Dry and mild...perfect springtime!

The early week charts and models have a pool of colder-than-usual Canadian air arriving in the central plains and sipping along the northern branch of our split jet stream which is pushing across the great lakes this week. This means a cool down of sorts, an increase in cloudiness, and depending on humidity levels, a chance of diurnal shower activity. This will be a relatively short-lived event, it seems, with CFP by noon tomorrow, and any chance of precip drying up by tuesday AM.

Later in the week (thurs-fri?) looks like a trough might build in from pac-nw, depending on what jet decides to do. Aleution low is progged to trip a strong downslope impulse east of the front range of the Rockies, vis-a-vis the northern branch of the polar jet, or maybe a coupled jet might evolve. Either feature will provide some potential for precip. We will see.

Posted by pierre at 10:26 PM | Permalink

Weather Display (the software that "powers" lakevilleweather.com) can utilize text-to-voice technology to produce an audio file of whatever weather data you want. I have added the feature to the website now, and it updates every 10 minutes. It's pretty cool! Look for your plugin's player to show up below the current conditions area on the home page. Right now file size is running about 1.0-1.5 MB depending on the length of the forecast text. That is causing some up load probs, as I think WD's FTP protocol likes to "rush" the upload batch along (the audio file is about one of 50 or so files that gets created and uploaded by the server every 5 minutes). So unfortunately, there are some times when the broadcast gets "cut off" before it is done.

Next step is to "stream" the file rather than just embed it. From my research, embeding plugin media is old-school, and never was very stable to begin with in many browser environments. In the meantime, enjoy the new "voice" of lakevilleweather.com!!

Posted by pierre at 10:03 PM | Permalink

Well, this weekend should prove to be another nice spring for Lakeville and the Twin Cities Metro. Forecasters have highs predicted in the 60's. I am hoping to see 72 before another upper-level low drags in cooler air that is tanked up over British Columbia this weekend. Shouldn't be rain until monday am at the earliest, and it all depends on how much the atmosphere dries up this weekend. Right now RH values are in the 90's at the surface (currently 92% here at KMNLAKEV2). Computer models are trying to handle another "split flow" setup in the jetstream early next week, which would support another "lingering" event of showers and sun. Still no real severe or heavy convective activity progged for the area, and that will not change until we get a unified "normal" spring jet. The polar jet seems to keep getting pointed out in soundings and plots well north of Winnipeg, and we would have to see it drop down to the lattitude of Bemidji, with troughs pumping Gulf of Mexico for moisture before we will see some good typical springtime thunder.

This isn't too far off normal, however. I am just hoping that May 2006 surpasses May 2005 for weather quality. We got stuck under a split jet last year that kept skies gray, damp, and cool. Yuck! So for now, enjoy the weekend, and keep your fingers crossed!

Posted by pierre at 11:56 PM | Permalink

A new blog is born! Each day I intend to give commentary on weather, show status of the lakevilleweather.com site and station, and use this as a platform for new weather-blog tech and ideas. Thanks for checking in!

Posted by pierre at 2:31 PM | Permalink