lakeville weather journal

Tame late June, post-solstice pattern in place currently...and I don't think anyone is really complaining!! This spring has not been very wet, however...and I think this is our only complaint here in Lakeville. Now that summer is here, maybe some July variety storms can help us out. We may get the chance Friday night into Saturday.

Currently, upper jet will flatten its amplitude before assuming a more zonal flow to begin July with. As mentioned last time, models still link this transition with a trough that will become more long-wave, and enter frontogenesis on the lee side of the Rockies tomorrow night. Low pressure will evolve over the NE plains and (depending on jet positon) may generate enough isentropic upglide to its east to give genesis to a warm front. Should Gulf air get tapped, system could intensify quickly before cold front passes area mid-Saturday AM. ETA model progs the system to take a more southwest-northeast path, with MN staying clear of a warm-sector MCS. GFS plots the low further north near FAR, hinting at the "run-home-to-mama" scenario it loves...you guessed it...triple point over the Couteau des Praries. We will have to see later runs to get a grip on ensemble differences.

Saturday into Independence Day, both models trend the pattern to zonality, giving creedence to more of what we saw early this week: short wave parade. Again, without a long-wave system in the output statistics, and with general solstice cT airmass in place, these ripples will be hard to predict. Fair weather should prevail for the most part, however, and any precip will be dirunal, "splash and dash" activity.

THURS... Hazy, but clear. (Haze will remain from Saskatchewan fires) High 84, SW wind 5 mph. Low 62

FRI... Clear in AM , then increasing clouds, high 86. Wind SSE 5-10. 50% chc thunder after 6pm, Low 65

SAT... Cloudy in AM, then clearing after 10 am, high 82. SW wind turning N, low 60

SUN thru INDEPENDENCE DAY... Seasonal. Highs 82-86.

Posted by pierre at 11:18 PM | Permalink

Short hiatus here on the journal...but weather has been generally typical for late June-early July...and we should just enjoy it. Last system I went into depth on focused on the upper jet pegging itself over the ND-MN area, with a strong northwest flow sending shortwave ripples across the Gopher state. As a resut, June precip caught up over much of the state, and a few convective spurts generated some strong storms on Saturday. The last of these ripples should graze MN today before the jet cuts into an upper low which will take the backside of the jet off the NW flow by late Friday. Right now there is some evidence to suggest this return to zonal flow by the upper jet will trigger a frontal event for the beginning of the holiday weekend, however, at 84 hours out the certainty still isn't there.

TUESDAY...Clear til about 1100, then turning Partly Cloudy, maybe passing shower. High 80

WEDNESDAY...Clear, High 80.

Posted by pierre at 7:50 AM | Permalink

Mainly zonal flow occuring in the current forecast period. Nice, dry air and milder summer weather is emitting from a high pressure ridge centered on the Gopher State today. Upper jet is pegged straight abover as well, and corresponding NW flow below it is damening temps only slightly amidst max heating of summer solstice. Some ripples of low pressure are riding along the jet, however, and they pose forecast challanges as model outputs don't handle these weaker impulses very well...nonetheless, we can hint at a general chance of precip and cloud cover under the "garden variety" forecaster schema.

First shortwave comes racing through mainly northern MN and WI later today, as depicted by 300MB heights in both ETA and GFS. Second wave breezes in on its heels tomorrow night, and then a stronger trough/surface front approaches for later in the weekend. Humiditiy and precipitable water values all on the rise as weekend progresses. However, models do not predict a major flow shift...with the polar jet still dominating the upper MN atmosphere through Saturday. Slight troughing hinted by longer term models by late weekend, but not in time - or enough - to allow Gulf or Tex-Mex flows into the upper midwest. Will look at later model runs to verify, but for now, generally nice summer weekend in store...

THURSDAY... Partly Cloudy, High 78. Low 55, NW wind 5-10.

FRIDAY...Partly Cloudy, High 82, 30% chc of showers in late afternoon, low 57, NW wind 5-10

SATURDAY...Partly Cloudy, High 80. 50% chc showers/thunder after 6pm., Low 60.

Posted by pierre at 1:04 PM | Permalink

After over a month of "beta" testing and fighting with different browser quirks and wrestling out code problems, we have renovated our website. We hope you like the new look and feel of the site, and enjoy the new content as well. Here is a rundown of the "features" we included in what we refer to as Lakeville Weather 2.0 :

More June rain is expected today across the southern and central parts of MN, including Lakeville. Currently (0900 CDT) a dissipating MCS is dropping some very light precip as is slides off towards the SE after trekking across Dakota overnight. Current SFC low in Central NE per NOAA-MESONET analysis should slide northeast into the Sioux Empire by later this afternoon. A very pronounced mid-level trough associated with the low will move to a position near the I-29 corridoor in Dakota by mid-day before flattening a bit as frontogenisis occurs downline with a triple-point setup. The warm front for the triple-point is progged to evolve throughout the day, extending from the low ESE-ward, and pushing north. However, common thought among the WFO's early this AM is that the cooling effects of the dissipating MCS will halt northward propogation of the warm front. Current satellite imagry does show extensive MCS cloud cover over southern 1/2 of MN and northern 1/2 of IA, so this may indeed occur. However, I cannot rule out the chance that cloud dissipation will occur more rapidly, and warmer air surges father north than expected. Given a relatively strong LLJ core progged to nose into southern MN by 00Z on the most recent ETA model run, there could be a good possibility of southern MN getting exposed to the warm sector, and the triple-point stitting somewhere between SUX and OTG by the time convection re-fires around 21Z-00Z this afternoon/evening. Will have to keep close eye on it throughout the day...Other severe weather factors to watch as well: 1) position of LLJ per soundings (specifically the left front of the jet max) 2) evolution of instabilities per soundings, as models paint strongest CAPE and theta-E energies over SE Sodak...if they align more with the triple point, elevated convection potential increases.

TUESDAY... Mostly Cloudy AM skies and sprinkles clearing by mid-day. Thunderstorms redevelop by late afternoon, 60% chc of precip after 6PM for Lakeville. High 82, S winds 5-10. Low 62.

WEDNESDAY... Mostly Clear, partly cloudy in evening, high 85. 30% chc of showers or thunder after sundown. Low 58. SW wind 5-15.

THURSDAY...Partly Cloudy, High 83. Low 62.

Posted by pierre at 8:47 AM | Permalink

FYI to you avid readers and users of lakevilleweather.com: our rain gauge has been operating incorrectly over the last couple weeks or so. Last weekend's convective activity had produced the most significant rainfall, and our fear of a blockage in the self-tipping bucket's funnel was confirmed when it was pouring outside, neighboring stations were recording rainfall rates of .50"/hour or more, and we were showing zilch. The blockage has been cleared now, and recent light precip activity has been registering on the system. In addition, we are in the process of using neighboring station data as well as rule-of-thumb estimates from physical observation and NEXRAD rain total records to reconstruct precip data for the record archive.

Posted by pierre at 8:41 AM | Permalink

I have been caught up with studies for recurrent training this week, so I have not dedicated much time to the ol' forecasting, however...I am relatively pleased with the longer-term shot at a forecast in my last post. The most significant deviation from my forecast was the temps, and some different precip chances here and there. Otherwise, we are on track.

Nice weekend setup for convection potential (once again) for the area. Deep-trough system from the Pac-NW came off the Rockies yesterday with some hardcore supercells in parts of Eastern MT. These "elevated" storms rolled off the Bighorn Mtn range and gulped up warm advection fuel from the LLJ as they propogated NE across the eastern MT high plains. Baseball and larger-sized hail, along with 85 mph winds were reported in Miles City, MT from the storms.

The same system has now moved east and has settled in overnight on the shores of Lake Oahe (MO River Valley) through the Dakotas. Sfc low centered near Mitchell, SD per mesonet readings at this time, with warm front a little more pronounced per the 00Z radiosonde plots...700MB analysis of the data shows the warm sector has surged a little further north, with current warm front extending thru a steep arc roughly ATY-FAR-FFM-AXN-HCD-FBL-LSE. From the sfc low, front has technically occluded along the trough boundary, running retro up through ABR-DVL- just west of Lake Winnepeg, and then stretching back to Medicine Hat, AB, where closed low spins the top end.

Not much movement of the front is expected overnight from model outputs, and to boot the strong S-SW flow of warm tex-mex air has now started to sip Gulf Moisture. Strong capping in place overnight per soundings, which show a decent mid-level inversion between 9000-13000 feet. ETA has a vorticity max progged near the ABR-ATY area for 18Z, and this should begin the breaking of the cap. The GFS painted the v-max same local, but later (00Z), and this is where the two models begin to stray from each other.

GFS pushed precip maxes out of the Sioux Empire overnight Fri into mid-AM Sat. The Sioux Empire is a favorite genesis location for the GFS this season, and I don't know why it has such a strong bias for it... for it has never held too true (yet). ETA has precip maxes painted off of its happy hunting ground this season - The Couteau des Praries and moving swiftly SSE, with higher chcs of soaking for southern MN. ETA has had better luck with this type of a setup, but with the strong LLJ from the SW ahead of the front, I don't see the overpronounced SE propogation as realistic.

Splitting the difference on timing and locality is my bet for now. I forsee storm genesis between the Couteau and the MN River Valley sometime between 21Z and 00Z. Propogation will be more easterly, and I think the MCS will form along the vort max line, which the GFS did a nice job painting SW-NE from the FSD area up through BRD around this time. This is a "classic" central MN setup for severe weather, and I will be shocked if we don't see WW's issued by by late afternoon, all things considered. I personally liked the MPX-WFO early PM discussion, outlining a similar outlook, but holding off on definitive severe threats. Their weekend outlook focused on the shortwaves emitting from the closed AB/SK low...but I think the 00Z model runs actually link up our weekend weather with the upper jet, now troughing in the intermountain west, soon to go zonal and bring a Tex-Mex low up to the mid-plains late Saturday. I call for precip chances rekindled on Fathers Day, with convection potential evident as well. More updates late tomorrow, hopefully, and thru the weekend!!

FRIDAY... Mostly Cloudy in AM, turning partly cloudy, hot, steamy by afternoon. High 87. 60% chc of strong thunderstorms after 6PM, low 70. S-SW winds 10-15 mph,

SATURDAY...Wake up to 30% chc of lingering thunder, then clearing through afternoon, high 82. Low 60. West winds 6-10 mph, calming and turning NW after midnight.

FATHERS DAY...Partly Cloudy, High 86. 40% chc of thunder approaching sundown thru overnight hours. Low 70.

Posted by pierre at 12:02 AM | Permalink

This weekend...ugh. My forecast was close...the real precip stayed well north and south of Lakeville, however. We did see some passing showers...but they were just passing. Not even enough to measure in the bucket. Only about 20 minutes south of here, however, it was a deluge overnight Friday into Saturday. Folks up north at their cabins were much more soggy as well. Temps fell right out of the bottom to boot, making it seem much more like April again...taking everyone for a shock as we have seem above-norm temps for the majority of May and June so far. It cleared up this afternoon after the progged shortwave breezed by faster than expected before the return of warmer, drier air made its entrance.

That push of warmer and drier air will fill in from the desert SW, as a mid-to-upper level ridge balloons northward from New Mexico through the first half of the week. The jet is digging a nice trough along the Pac-NW seaboard from BC on down to the OR coast. Lobes of energy will break off and ride the upper periphery of the ridge over the Northern Rockies and along the "Hi-Line" through MT and ND. These weak shortwaves will bring better chances of showers and t-storms to these locals as well as our friends in northwest MN over the next couple days.

Meanwhile, we will remain dry. Right now the models have no hints of precip, instability, or otherwise until closer to week-end. With the upper flow zonal, the mid level northwesterly, and the lower level filling in with the sinking, drier air, it is hard to imagine anything other than bluebird skies and warmer temps. MOS from the short range GFS and ETA concurs scoring "CL" and "SC" cloud cover codes (clear and scattered) through the next 36 hours at least for the KLVN data point. There is some disagreement bewteen models as to whether or not some cloud cover from the northern MN shortwave Tues to Wed may slip south enough to give us BK to OV (broken to overcast) codings for those days.

Next challenge will be timing of the main Pacific system, which should finally push over the Rockies in entirety by Thursday, assuming the Tex-Mex ridge has moved well enough east by then (may get some blocking from the arrival of the hobbling T.S. Alberto in FL). This would give rise to precip chances by Friday. Until then, all the models agree on the veritable lack of precip chcs and increasing temps. Here is your result...enjoy!!

MONDAY...Clear Skies...High of 77. Light and Variable to calm winds. Low 55

TUESDAY...Scattered Clouds, mostly sunny however, and high of 82. Light and Variable wind. Low 57

WEDNESDAY...Clear Skies, High 84. NW wind 5 mph. Low 60

THURS thru SAT... Increasing Clouds thurs PM and Fri. Chance of precip increases Fri into Sat. Highs mid 80's.

Posted by pierre at 10:36 PM | Permalink

A new synopsis seems to have taken over the next three-day period for the weather setup here in Lakeville. The week or so has been downright spectacular, as noted in many previous posts with "July in June" weather dominating. My predictions for fair weather and higher temps than expected by the other WFO's were on the mark. That pattern will return, but not until a slight regression occurs this weekend.

High pressure in the mid-to-upper levels of the atmosphere is dominating the central US. Yesterday we saw a nearly perfect day as a result. High above us, the upper jet stream is coursing way up north, and digging sharply southward east of Lake Superior, placing the ridge axis directly over the Gopher State. Meanwhile the low-level jet, which is primarilly responsible for conveying moisture to the atmosphere, has nosed in from the SW overnight. Inherently warmer and moister than the dominating dryer cooler air aloft, the LLJ has set off some showers around the area this AM.

Going forward, this LLJ entrance will become more meridianal and tap gulf moisture, so models point to a surface low in NE that will extend a warm frontal boundary along the LLJ's postion and running across northern IA. If the warm front advances northward any, we will see much more in the way of precip over the next 48 hrs. Unfortunately, the models do not prog the warm front to move north of here, so we will remain cooler - and as the low moves out of NE into IA, winds will increase for us from the E and NE over the period. It will remain unsettled and showery as well, but no thunder to speak of as the upper ridge contains too much cool and dry air from Manitoba to spark large storms. Some elevated convection from dirunal heating cannot be ruled out...however no severe wx is chanced. Today (Fri) is only day really lacking sun in my optomistic opinion...and the weekend will remain relatively nice, albeit cooler -- much more like June!!

FRIDAY... Mostly Cloudy, High 66, Scatterd showers increasing in potential as day wears on. E wind 5-10 mph, Low of 55, rain chc 30% daytime, 60% after supper.

SATURDAY... Mostly Cloudy in AM then partial Clearing in the day. High 70. Breezy ENE wind 10-15 mph turning NNW. Low 50

SUNDAY...Partly Cloudy, warmer, high 77. Slight chance of a late afternoon thunderstorm (30%) Low, 55.

Posted by pierre at 8:38 AM | Permalink

This was the MPX WSR-88D NEXRAD image from last night when the predicted line of TSRA finally made it into the TC Metro. This particular screen capture is right when the loudest clap of thunder woke me up! The line was just getting into Lakeville, and as you can see...it left us pretty quickly as well. It was quite the lightshow, however we only received 0.03" of rain from the whole deal. That is still not enough!!

In any case, we continue to experience July this June...drier air filled in quickly and noticably today as the front leisurely passed through midday. Models are now pointing to a very fixated westerly upper air pattern for the week, with a short wave passing through Thursday and Friday, and a much more significant wave progged to arrive later in the weekend. Between now and then, high pressure will dominate once again...winds will be north-northwesterly, and dirunal heating will maximize in the dryness. Summer is here...albeit early!

WEDNESDAY...Mostly sunny, high of 87. Northwest wind between 5 and 10 mph. Low 59.

THURSDAY...Sunny in AM with increasing clouds after lunch. High 82, light and variable wind. Low 55.

FRIDAY...20% chc showers in AM, then partly cloudy, high of 80. Better chc of showers or a thunderstorm after dinner. Low of 57.

Posted by pierre at 11:45 PM | Permalink

(update at 1945 CDT)

Things are getting more interesting for the metro area as more storms are beginning to form more west and southwest of here. Most of todays activity (as you can see by the radar clip) has remain well north of the TC metro. Now that a strong CAP is finally being eroded by the oncoming low and surface front (it got well over 90 today out west...and the atmosphere was warm all the way up)...things are popping in the right places for a Lakeville TSRA event.

I have circled the main area of genesis in red, and drawn arrows of probable storm motion. Looking at satellite returns, the main storms in this red circle have definitavely "broken" the CAP...their tops are distinctive among the overall surrounding stratus and stratocu layer. I expect other cells to follow suit, building behind these cells you see south of Willmar.

In the blue circle, I have pointed another line showing more characteristics of the CAP break and subsequent "backbuilding"... STC and parts west were well within that 90+ degree CAP today, and once the earlier round of TSRA pushed through just about 5pm, the atmosphere destabilized in earnest...allowing for this secondary line, which continues to lengthen and intensify as I write.

Posted by pierre at 7:38 PM | Permalink

Things came together over the last 24-36 hours in model runs, and now that the infamously expected trough has slid over the lee side of the Northern Rockies, it has intensified this AM on the Highline in MT. Satellite water vapor showed a definitive cyclonic swirl associated with the system, and surface front kicked off t-storms across the western Dakotas overnight. As for us, slight vort-max pushed by overnight as well, triggering TSRA over eastern counties of MN, mainly north of Lakeville, and east of the TC Metro.

Later today we will need some second looks at the upper air soundings, ABR INL and MSP all key in determining where best instability is occuring in late afternoon. All models point to theta-E ridge extending up into Sioux Empire, with instabilitiy building east rapidly with dirunal heating. MT/ND frontal system will dig SE and trigger strong convection from Dakotas, through NE and KS...where SPC is most worried for moderately severe weather. Any activity will have no problem tracking easterly towards TC metro. I had 50% chc going into this entry, MPX has now gone 60% with mention of severe, and I will concur. Updates to follow....

TODAY...MONDAY... Partly Cloudy, high 84, S wind 5-10, 60% chc Thunderstorms by dinnertime? Low 63

TUESDAY... Partly Cloudy, high 82, 40% chc showers and thunderstorms. SW wind turning W by midday.

Posted by pierre at 8:03 AM | Permalink

I was looking around the neighborhood today, and one thing is certain...we need rain! We went through May with only 1.02" of rain...whereas our normal (for the Minneapolis area) is 3.24". The deficit is showing in the browning hues of lawns across suburbia.

Yet another "chance" for Mother Nature to assist us in watering comes through tomorrow and Monday, as a low pressure system that has given some nice soakings to our Dakotan friends out west makes its way into MN. Currently, the associated surface boundary is occluded and on the verge of diffusing. Culprit is a lazy upper jet and a strong ridge of high pressure that is anchored just to our east. Along the front, which is pretty much parked right along the MO river through the Dakotas, late day storms fired in the afternoon heat...they moved little, and are now dissapating rapidly. The outflow boundary gusted out to near Mankato, MN, and just south and east of there with help of the left-front exit region of the mid-upper jet streak, some more convection fired just about sundown. It also is dissapating and sliding SSE.

The Dakota MCS tonight will dissapate and I don't expect much debris moving east towards us for the AM. The front will dissapate as well. The remaining short wave will propogate through the Dakotas tomorrow, giving rise to precip chances for our region. The 00Z GFS model run paints it well on 700MB heights moving across the Red River Valley between 1pm and 7pm Sunday. Simultaneously, both the ETA and GFS plots show a strong theta-E ridge across the Couteu des Praries, and high values throught west-central MN. Precip H20 values and vorticities line up here ask well. It is fair to say convective activity will start here...the question is where will it go? Most data points to NE propogation, which may leave us on the drier side of chances, as I foresee t-storm development along a FFM-ATY line, moving NE.

Another problem with my assesment of the models tonight...NWS-MPXWFO is not exactly jiving. They wrote up reasoning from the 18Z model runs...I am currently ahead of them and not sure what the overnighters are seeing in the cards. Previous thinking by the WFO's was to see the current Dakota frontal/wave dissapate, and stronger shortwave to race in for a more-likely Monday t-storm event. Evidence of such a system remains...but without the congruity, I am going to leave things open until a better look tomorrow. I am more confident about a W-MN event tomorrow than I am about everyone (including early yesterday SPC assesments) think Monday will rock.

SUNDAY... Mostly Sunny, increasing cloudiness, high 85, S wind 5-15, low 62, 40% chc showers late

MONDAY... Partly Cloudy, high 82, SW wind 5-10, 50% chc Thunderstorms by dinnertime? Low 60

TUESDAY... Partly Cloudy, high 83

Posted by pierre at 12:12 AM | Permalink

Here it is, beggining of June and it feels like July. Early July, at least...with the sunny skies, moderate humidity, and warm temps. Diurnal showers and thunderstorms have visited the last couple days as well. Overall high pressure is dominating, but small "ripples" in the atmosphere - short wave troughs of low pressure - are slipping though the relatively steady jetstream. These ripples, coupled with daytime heating and a bit of latent moisture and energy, are creating the shower activity.

Wednesday and thursday's activity was pretty textbook. This weekend we will continue that trend, along with a possible "longer" wave coming through Sunday or Monday. Models have not concured on the extent, intensity, or positioning of this wave, but the certainty is that a more pronounced precip and convection event will evolve sometime between late Sunday and late Monday. GFS is pointing more towards Monday night, and given the omega block in place in the eastern US by the end of the weekend, this seems like the more reasonable guess.

SPC has looked at the models in this light as well, noting that the genesis of the wave will be the Pac-NW, intensifying as it downslopes the Front Range thru MT and WY Sunday into Monday. If the jet allows digging to occur over the Rockies, and we get enough southerly flow in advance of the wave, things may light up Monday.

For the weekend, though, hit the lakes! Head out of town! It is going to be Minnesota nice...

FRIDAY... Mostly Sunny, increasing clouds through midday, then clearing again at night. 20% chc passing dirunal showers...High 83, Low 57, wind light from the NNW

SATURDAY ... Carbon Copy of Friday, temps slightly warmer 85/60

SUNDAY ... Partly Cloudy, more humid, High 85, SE wind 5-10, low 62, 20% chc showers after midnight

MONDAY ... AM showers, then clearing, High 87, S wind 5-10, 30% chc thunderstorms in PM

Posted by pierre at 12:03 AM | Permalink