Joe’s Weather Blog: Drought easing rain chances next week (FRI-8/10)

A rain opportunity is going to open up next week. Right now the best chances look to be on Tuesday and Wednesday with perhaps some lingering activity in the region on Thursday. It’s possible that some areas may see over 2″ of rain from this set-up…perhaps even more than that. It’s possible that this system will bring more widespread rains to the region in that TUE>THU time frame. It won’t erase the drought…some need more than 12″ for that to happen (and not all at once)…but this may help things out.



Forecast:

Tonight: Any late afternoon/early evening activity drifts and or falls apart overnight. Fair skies and seasonable with lows in the  60s

This weekend: Mostly sunny and seasonably hot with highs around 90°. The dew points won’t be too terrible so not much of a heat index to speak of. Pretty light winds from the NE on Saturday and SE on Sunday…a bit breezier then.



Discussion:

Summer continues to move along in the Plains…temperatures today are seasonable this afternoon…mostly around 90° or so…and storms are starting to fire up near and north of the I-70 corridor as I expected yesterday. These will gradually drift southwards this evening and fade away.

The 1PM surface map shows a weak front in the region…really it’s not much of a front…more of a wind shift line.

Very subtle at that too…not the west winds at Harrisonville (95°) and the north winds across areas from I-70 northwards.

Above the surface though there is a bit more of an elevated wind shift. The instability has built up sufficiently and with temperatures near or above 90° there is a lot of instability out there. Plus we’re really not capped so there is nothing to keep storms from trying to form. The winds though in the atmosphere overall are rather light…so not a lot of shear to allow the storms to organize. As a result, for those lucky to get some rain…some locally heavy rain will fall…along with the potential for 40-60 MPH wind gusts in some localized areas.

Meanwhile…after a seasonable weekend…my attention shifts towards the potential rain maker next week.

The area of concern is down towards Texas today. It’s a broad cluster of rain and thunderstorms. This area will in time gradually consolidate into a weak upper level low. This low in the mid levels of the atmosphere will gradually migrate northwards.

This soon to be upper level feature will create a “colder” pocket of air in the mid levels of the atmosphere over the weekend…and then drift northwards. Where exactly it goes…considering it won’t exist for another 24 hours or so…will help create our rain opportunities next week.

Now for some perspective…I want you to think about this soon-to-be upper level feature as a bicycle wheel. The wheel is sort of horizontal in the atmosphere and is spinning around counter clockwise. Obviously with a bicycle there are lots of spokes attached to the wheel. Now think about each spoke as a weak little atmospheric disturbance…in the weather business we call these vorticity maxs. Each max is spinning around “mama” storm…and depending on where “mama” storm sets up…it will go a long ways in where these little weak maxes go.

These “maxes” or areas of vorticity represent lift. As the lift interacts with the atmosphere it will set of areas of rain and some thunderstorm activity. These areas will rotate around the mama storm and move NE or NNE and then N and then NNW again in a counter clockwise way.

Now the question is where exactly this “mama” storm sets up because it will determine where these spokes end up moving and where the best rains will move towards and through.

This is the part the our model data won’t do well with. There are strong suggestions that this will happen…and I’m strongly thinking this will happen…but IF mama storm sets up more towards western KS…and not central KS…then the spokes will migrate more south to north BUT west of the KC area. This brings the better rains towards the west of the Metro (mostly).

NOW IF this “mama” storm sets up farther east…more towards central and east-central KS…this would place more of the I-35 corridor in the higher rain potential and again there would be some decent potential to decent rain totals.

The model data today is coming to agreement (again this is model data…not necessarily reality). 1st the GFS which wasn’t so aggressive BUT now is.

and the EURO is perhaps even better looking for rain.

When looking at the EURO above…if you use some imagination…you can almost see how the rain moves from the SW>NE south of KC (where the darker red shading is located) and also more towards central KS…from the south to north to northwest to west around the “mama” storm.

The way this DOES NOT play out nicely for us…and I do have some concerns for parts of N MO…is IF the best rains do what the EURO above is showing and sort of split to the south and towards the west and NW of KC…leaving the I-35 corridor with something, but perhaps not as much as what we have the potential for.

The good news IF IF this plays out nicely…some areas may easily see over 2″ of rain.

Will Phillips emailed me this picture from one of the many vivid rain shafts yesterday. It was taken in DeSoto and was showing the view back towards the SW around the Lawrence area.

Joe

 

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