August, 2012

Some Changes to Saturday………..Isolated Tornado Risk for Part of Viewing Area

August 31st, 2012 at 10:13 pm by under Chad's WLFI Weather Blog

I will need to put isolated tornado risk northeastward to Lafayette, Pine Village, Frankfort, Crawfordsville & Attica to Covington to Perrysville.

Why?  It appears main wave of rain & a few t’storms will pass Saturday morning-midday.  This wave will pivot northwestward & actually put us in a bit of a break for a little bit in the afternoon.

With some peeks of sun possible, new scattered showers/storms will pop just east of Isaacs center in a warm, tropical, rather sheared environment.  This spoke around Isaac will pivot our way & an isolated, brief, EF0 spin-up or two cannot be ruled out.

Waves of scattered showers & a few t’storms (average of 50% coverage) will pivot around Isaac as he pivots up near I-70 Sunday.  Even Monday, some scattered showers & a few t’storms will pass with around 40% coverage.


Thank You Isaac! 112 In South Dakota, 108 Nebraska!

August 31st, 2012 at 4:34 pm by under Chad's WLFI Weather Blog

Historic heat wave continues to grip areas from Montana to Iowa to Nebraska, the Dakotas & Colorado.  It will bring 100 to the Northeast this weekend.

If not for Isaac 100 would be here & if we had dry soils, 105.  The heat has been absolutely incredibly to our northwest with 112 at Winner, South Dakota.  Even Denver set an all-time late-season record of 97, as did Valentine, Nebraska at 108!

Isaac clouds & showers/t’storms & circulation will keep the heat wave at bay & a cold front will cut the heat wave in the Plains, Great Lakes & Northeast by early- to mid-next week.


Now-Monday………….Weather & Rainfall Totals by Monday…..Any Isolated Tornadoes?

August 31st, 2012 at 2:40 pm by under Chad's WLFI Weather Blog

1-3″ with isolated 4″ amounts…………..south to southeast winds to 25 mph & bands of showers & some t’storms.

Isolated tornado threat will exist south & southwest of us, the way it looks right now.  This has been the trend, but we will watch this.


Now-Monday Forecast

August 31st, 2012 at 12:09 pm by under Chad's WLFI Weather Blog

On-going forecast looks good.  Narrow wave of isolated showers/t’showers along I-74 still looks good today with an increase in cloud from south to north with the coolest readings in our southern counties.  I may tweak the temp down a couple degrees, given this Isaac cloud cover looking thicker than anticipated.  So, upper 80s south, 90 middle & lower 90s north will do.

Isaac remnants will NOT bring a solid, steady rain for 3 days, but waves/bands of showers & a few t’storms.  It appears the heaviest, most widespread band may still be Saturday afternoon-evening.

Like 60% coverage of rainfall Saturday, 50% Sunday & upped Monday unfortunately to 40%, given trend for more in the way of some scattered showers/t’showers on Labor Day itself.

1-3″ of rainfall Saturday-Monday still looks good.  A couple isolated 4″ amounts are possible in our far northwest counties.


Isaac Update

August 30th, 2012 at 10:06 pm by under Chad's WLFI Weather Blog

Former hurricane/tropical storm tracks through/near our area since 1885 plotted on map below:

Only change to the forecast is for isolated t’showers/showers along I-74 tomorrow as the outermost bands of Isaac may pop some of these on that I-74 corridor.  Any one of these will tend to die off in the evening.  A couple more may move in that I-74 corridor Saturday morning, followed by a wave of showers/storms in the afternoon-evening where most/entire viewing area will be affected.

Overall, clouds will tend to increase from south to north through the day.

I went cooler at 90 in the far south to 96 in the northwest & 93 in Lafayette.

1-3″ rain still looks good for the viewing area for Saturday-Monday totals.  Still looks like best potential of an isolated 4″ amount would be Newton/Jasper.

With the wettest August since 1987 in parts of the viewing area, drought conditions have continued to improve.  Extreme to Exceptional Drought is no longer found in the viewing area.  Although Moderate to Severe Drought conditions are still found, we have seen nice downgrades to the drought over the past 3 weeks.

The remnants of Isaac will help even more.


100 Not Far Away Tomorrow

August 30th, 2012 at 4:15 pm by under Chad's WLFI Weather Blog

Record Labor Day weekend heat wave will hit areas to our northwest, north & northeast.  If not for Isaac, this would be here, too.  Readings as high as 107 will continue to occur in Nebraska with the potential of 100 in parts of the Northeast, even.

Regardless a 92- to 96-degree day will occur tomorrow in our viewing area.


Rainfall Projections & Timing with Isaac

August 30th, 2012 at 2:01 pm by under Chad's WLFI Weather Blog

Looks like showers/few storms would tend to move in Saturday midday & onward & pass in a periodic fashion through Sunday.  Right now, looks like that first initial wave would be the heaviest & most-widespread.

A few showers/t’storms may pivot in on Isaac’s backside Monday, but I would not cancel outdoor plans per sey.  Just be prepared to go inside for perhaps 30 minutes a time or two.

Winds will run 15-25 mph from Isaac Saturday & be pretty calm as he passes directly overhead Sunday.


Rainfall Projections for Saturday-Sunday…..Flash Flood Guidance

August 30th, 2012 at 10:28 am by under Chad's WLFI Weather Blog

1-3″ looks like a good forecast for the area with a couple isolated 4″ amounts total from Isaac Saturday-Sunday-Monday.  Right now, it does not look like flooding will be a big issue.  It appears showers/some storms will arrive Saturday (up to 70% coverage late) with some Saturday night & additional showers & few storms Sunday (50%).  A few showers/storms may pivot in Monday, but coverage then will run at 30%.  A passing cold front will bring 30% coverage of showers/storms Tuesday, followed by dry, cooler, pleasant weather Wednesday-Friday of next week.

Why am I not talking up the flooding?

Below in the first graphic is a flash flood guidance graphic showing how much rain we could take on in a 6-hour period before we see flooding.  You can see most of the area can handle 4″ in 6 hours, but anything above that in 6 hours would result in flooding.

In the second graphic, you can see that NOAA flash flood guidance shows that we could handle 3″ in 3 hours, but anything above that would bring flooding.

With largely 1-3″ over a 3-day period (isolated 4″ amount or two), such rainfall does not exceed the threshold for flooding in the area with current deficits & soil moisture (even with recent heavy rainfall).


Smokey; Record-Breaking Heat Wave Plains to Great Lakes (Temperatures to 108!)…….Tropical Depression Moving Right Overhead This Weekend

August 29th, 2012 at 6:53 pm by under Chad's WLFI Weather Blog

LATE AUGUST EXTREME PLAINS-GREAT LAKES HEAT WAVE WILL GET VERY CLOSE…….

Smoke from western & Plains fires has given our clear sky a pale, hazy appearance today.  The sunset will be golden, bronzy & smokey this evening.

An extreme, record-breaking heat wave from Montana to Minnesota & North Dakota to Iowa to Nebraska & Kansas to even Wisconsin & northern Illinois to the Northeast U.S. will bring widespread 100s & 90s to end this week & head into the weekend.  Temperatures today were as high as 108 in Nebraska & will be as high as 102 in Iowa & Wisconsin to end the week & up into the upper 90s to 100 in the northeast by the weekend.  Boston may see 98 & even Cleveland, Ohio may see 97.  Today, 100 occurred in Wyoming to Utah.  High to Extreme Fire Danger covers 10 states.

If not for Isaac, record heat would likely move into our area & 98-100 would be attainable.  105 would be likely if the soils were much drier & vegetation less lush from the ample August rainfall.  Mid 90s will be the highest we will do as clouds from the Isaac circulation move northward to end the week.  90s will still be very hot, but this significant heat wave to end August will set up with 97-108 just to our north, west & northwest.

TROPICAL DEPRESSION ISAAC WILL MOVE OVER OUR AREA……..

After 90s, highs around 78 are likely for the weekend with the main wave of rainfall on the right side of Isaac’s center with stiff winds at 20-25 mph.  This would tend to pass Saturday.  Low temperatures will only be around 71, as a tropical, water-logged atmosphere will exist.

As the actual center of Isaac passes overhead, it will tend to be more showery with diminishing winds.  This would tend to occur Sunday.

1-3″ of rainfall looks likely area-wide.  Isolated 4″ amounts are possible.


Isaac & His Impacts (As a Tropical Depression Here)……….Direct & Indirect

August 29th, 2012 at 10:23 am by under Chad's WLFI Weather Blog

Isaac is a heck of a Category 1 hurricane.  As we have learned from Katrina, Ike & now Isaac……….each Cat. 1, 2, 3, etc. is different.  Isaac is like a major hurricane in size, a Cat. 2 or 3 in surge with occasional Cat. 2 gusts, but is a Cat. 1 with sustained winds at 80 mph.  Ike was a Cat. 2 with a Cat. 4 surge at Galveston, Texas a few years back.  According to Army Corps of Engineers, 13′ surge over-topped an 8.5′ levee south of New Orleans.

Wind has gusted to 93 mph in downtown New Orleans from Isaac.  Gust of 106 mph occurred southeast of New Orleans.  Grand Isle gusted to 83 mph.  Flooding is widespread from surge & heavy rainfall from New Orleans to Biloxi.

Rainfall of 1-3″ is likely from Isaac here with 3-5″ in Illinois and up to 7″ in Missouri.  Rainfall is likely Saturday-Sunday with winds of 20-25 mph.  It is questionable whether any or how many showers will linger into Monday.

One good thing, Isaac will keep a major, record-breaking heat wave north & northwest of here.  We will see 90s Thursday & Friday, but the 100-102 temperatures will stay from near Kansas City to Omaha to Minneapolis to La Crosse.