The Outlook………Your Storm Pics……& Re-Cap

August 20th, 2014 at 10:04 am by under Chad's WLFI Weather Blog

Isolated t’storms are possible today with partly cloudy skies & highs of 85-90 with dew points in the upper 60s to lower 70s.

Showers & t’storms are likely late tonight-tomorrow morning as potential MCS develops along front & moves right over the viewing area.  An isolated severe storm or two is possible (wind/hail).  Locally-heavy rainfall is possible with it.

Looks like it will exit by afternoon, followed by some sun & rapidly-warming temperatures into the 85-90 range with dew points in the lower to middle 70s.

Some scattered re-development of t’storms cannot totally be ruled out in the late afternoon-evening with the intense heating expected.  If these develop, an isolated severe storm or two is possible (wind/hail).

Dangerous heat is expected Friday-Sunday (with a few storms Friday & isolated storms Saturday [couple of storms could break through cap] with a strongly-capped & dry Sunday).

Highs will run 90-95 with dew points as high as the middle 70s.  This could send heat indices to 106.

Heat Advisories are already in effect for southwest Indiana & Central Illinois NWS office may put out Heat Advisory soon for central & eastern Illinois.  Excessive Heat Warning is in effect for the St. Louis area & part of southwest Illinois where heat indices may reach 112 in places by the weekend.

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Thank you everyone for your valuable reports from yesterday & last night’s t’storms!

I also appreciate the great shots of the t’storms that you captured!  Thank you for sharing!

-Chad

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Although there were only two isolated reports of severe weather (tree over Old 25 near Americus & estimated gust to 60 mph at Tipton), the storms did produce three reports of pea to penny hail & two reports of 50 mph gusts (one measured at the White County Airport AWOS & the other northeast of Battle Ground).  Purdue Airport ASOS gusted to 44 mph & Frankfort measured gust of 45 mph.

Here is a re-cap of all of the updates:

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10:42 p.m.

We are in the clear, the entire viewing area is rain-free & calm.  No watch for areas of dense fog area-wide as skies clear.  Lows will drop into the 60s.

RAINFALL TOTALS FOR TODAY-TONIGHT:

DMA Map IIV

STORM REPORTS:

(Gusts Measured or Estimated at or Above 40 mph)

E60 mph  Tipton

M50 mph  White County Airport AWOS

E50 mph 3 Miles Northeast of Battle Ground

M45 mph  Frankfort

M44 mph  Purdue University Airport ASOS

Americus:  Tree Down, Partially Blocking Old Route 25

0.75″  Hail:  10 Miles East of Crawfordsville:

0.25″ Hail:  East of Frankfort

0.25″ Hail:  Tipton

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10:34 p.m.

Tipton County storm has gusted out.  Second microburst signature evident on radar in the eastern part of the county.

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10.22 p.m.

Last storm is an intense one over Tipton County at the moment.  Microburst possible with gust to 60 mph.  Pea hail also possible with +2″ per hour rainfall rates.

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10 p.m.

Chuck northeast of Frankfort measured 1.43″ of rainfall in 90 minutes.  Randy Rogers on the east side of Frankfort reported pea hail.

The Boone & Clinton County storm masses have completely congealed & now they will likely fall apart over the next hour.

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9:46 p.m.

A tree is blocking part of Old 25 near Americus, north of Buck Creek, in northeastern Tippecanoe County.  Law enforcement is on scene & highway department is en route, per dispatch.  This was the wind core we were tracking from Battle Ground to Buck Creek.

Storm mass in Clinton County is showing signs of collapsing rapidly, but not before belching out a gust of 50-55 mph southeast of Frankfort.  This is visible on radar.  Pea hail is also possible with it.

Flood Advisory in effect for Clinton, southern half of Carroll, northeastern Tippecanoe & western Howard County until 12:30 p.m.  Doppler radar estimates 2.30″ of rainfall in the past hour in north-central Clinton County.

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9:32 p.m.

The storms have morphed/congealed into cluster over Clinton County & they are in the process of morphing/congealing with the storms moving north out of Boone County.  Torrential rains are likely at the two gell & dump their load before collapsing.  The storms are being accompanied by nearly continuous lightning.

Wind may gust 40-50 mph south of Frankfort.  Pea hail is also possible.

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9:15 p.m.

Boy, as quick as the storms blew up on ouflow of White County storm, they have largely collapsed.  Now, the new storms are occurring from Owasco to Mulberry to Concord, Monroe & Frankfort.  These are likely peaking now & weill gell into a mass, then collapse to just some rain & thunder/lightning before completely dissipating.

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A mass of storms has formed in Montgomery/Boone & may actually haphazard move north & gell with the Clinton County storms to form a mass of storms with torrential rainfall.  Flash flooding may develop quickly over the next hour in Clinton County.

With no strong dynamics, the storms are CAPE & outflow-driven, moving about haphazardly…………….collapsing here, pulsing there, then gelling here & there & then raining themselves out.

For example, 40 minutes ago, White County was getting hammered & they are nearly completely rain-free now!

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8:47 p.m.

White County part of storm has collapsed, but new storm on outflow in Tippecanoe County is sagging through Battle Ground & Buck Creek toward Laf/West Laf.  Also, new t’storms are pulsing up from Cutler to Mulberry to Frankfort, Dayton & Concord.

White County Airport AWOS measured a gust of 50 mph.

Brief gust of 47-55 mph possible southeast of Battle Ground around Buck Creek & northwest of Heath.

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8:41 p.m.

Looks like NWS has brief Severe T’Storm Warning for southeastern White County, but storm is rapidly collapsing & building more on its southern flank (outflow boundary).  Look like as it re-evolves & becomes outflow-driven, it is sagging more toward Battle Ground & Buck Creek to perhaps West Lafayette/Lafayette.

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8:25 p.m.

Gust 55-60 mph possible southeastern White County/northwestern Carroll County with torrential rainfall.

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8:21 p.m.

Torrential t’storm working through the southern half of White County & far northwest Tippecanoe County.  Rainfall rates of up to 3.5″ hour are likely.  Gust to 55 mph possible near Chalmers with the storm visible on radar velocity.  Some pea hail is possible.

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RAINFALL TOTALS:

2.10″  Kentland

0.62″  Remington

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7:50 p.m.

Torrential t’storm is moving through eastern Benton County between U.S. 52 & I-65.  Rainfall rates of +2″ per hour, brief gust to 50 mph & pea hail are possible.  The worst core of it will pass from northeast of Benton Central High School to over the U.S. 231/I-65 interchange, eastward to Chalmers & perhaps Brookston.

Clinton County storm is just beginning to collapse.

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7:38 p.m.

Some +2″ per hour rainfall rates are occurring in southern Newton & Jasper County to central Benton County.  Flood Advisory is in effect for southern Newton, Jasper & northern Benton until 9:30 p.m.

The strongest pulsey storm (could belch out a gust to 50 mph) is in central Benton County.  Some pea to marble hail is possible there, too.

All of these storms are moving due east toward White & northwestern Tippecanoe County.

Heavy t’storm is also approaching Forest in Clinton County.

0.75″ diameter hail was reported east of Crawfordsville, near the Boone County line.

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6:28 p.m.

New scattered pulsey storms are popping again.  Like this afternoon, these storms quickly pop & intensify, then collapse, while a few new ones form nearby.  These storms & processes will be with us during the evening, then they will fade away.

Isolated severe wind gusts/hail still cannot be ruled out.

This is a result of re-charge as the sun comes out with the front in vicinity & up to 4500 residing in southeastern Illinois that is advecting some northward.  Dynamics are not good enough or organized, widespread, longer-lasting storms.

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5:25 p.m.

STORM REPORTS:

M44 mph  Purdue Airport ASOS

M32 mph  WLFI-TV

T’storms are in weakening mode in our eastern counties with new storms pulsing up southeast & east of the viewing area.  New spotty t’storms are popping in southern Montgomery County where temperatures are around 88 degrees with dew points around 72.

Will still maintain some scattered storms for the evening forecast & that isolated severe wind/hail threat.

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4:45 p.m.

Pulsey storms are tending to collapse in Carroll/Clinton counties.

Will keep a few scattered t’storms in the forecast for the evening as skies clear from west to east.  Some heating/re-charge will bring the potential of a few more popping up.

The night looks dry with that patchy dense fog developing.

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4:07 p.m.

The core of the rainfall is Tippecanoe County as of 4:10 p.m.  Some sporadic gusts of 40-50 mph are possible with the t’storms.  Measured a very brief, sudden gust to 32 mph at WLFI.

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3:40 p.m.

The same areas are getting the heavy rainfall AGAIN!

The south & southeast sides of Lafayette are largely dry AGAIN, but West Lafayette is getting a torrential downpour.

More is coming in from the west, too.

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It is very spotty in areas that need the rain.  The storms are very sporadic & pulsey there.

We will see if the t’storms can hold together over Tippecanoe/Fountain & more pop  to bring some rainfall to our east & northeast.

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3:32 p.m.

Storm north of Covington has weakend some, but is still putting out tremendous lightning & heavy rainfall.

Other storms are dotting the area.

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3:05 p.m.

There is a 90% chance of pea to marble (perhaps to penny) hail in southern Warren County to north of Covington in Fountain County.

Gust of 30-40 mph is also possible with the storm.

Scattered multi-cells of 40% will continue to pop.  Some of you will get a nice downpour, some of you absolutely nothing.

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3 p.m.

Scattered t’storms are found across the area.  SPC has Severe T’Storm Watch for Fulton County, but feel like severe threat is isolated for wind/hail.  The strongest storm right now is well southwest of that watch, west of Covington.

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1 p.m.

Surface CAPE is pushing 3000 J/kg in the viewing area right now with area of slowly-decaying showers in central Illinois & storm development in northeastern Illinois.

Some new multi-cell storms will likely form on outflow boundary moving out from the rain in Illinois.  This may briefly semi-organize into a broken line, but lack of great dynamics will preclude an organize, widespread squall line.

Pulsey, multi-cellular storms/clusters/broken line mode seems good in high-CAPE, low wind field environments along a surface front.

Isolated severe wind/hail still cannot be ruled out with that CAPE & also a low- & mid-level lapse rate at 7-8 C/km (rate of cooling as you move up in the lower atmosphere).

The strong low-level tropical flow of 70s dew points supports High Precipitable Water Values of +2″ support +2″/hour rainfall if you get under a t’storm.  I still prefer 40% coverage of t’storms.

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11 a.m.

Hot, humid weather with nice southwest winds will occur ahead of multi-cellular storms develop on front today.

Again, dynamics/wind fields aren’t great (bulk shear up to 25 kts), but very unstable environment will support storms of pulsey nature where they pulse up in intensity, but collapse quickly.  However, other storms tend to form nearby.

Isolated severe gusts/hail are possible in the pulse up/collapse processes.

40% coverage still seems reasonable in the afternoon & evening periods.

Storms will fade this evening, followed by patchy dense fog tonight-Wednesday morning.

Isolated storms are possible tomorrow (20% coverage) but it looks as if the “scattered storm” wording with isolated severe potential may return Thursday with similar pulsey storms with wind/hail threat.  40% coverage Thursday seems better than former 35%.

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Monday, 10:15 p.m.

Tomorrow looks very juicy with highs of 85-90 with dew points to the lower 70s.  It looks actually more & more unstable in the afternoon.  As a matter of fact, surface CAPE of up to 4000 is possible by afternoon with scattered t’storms firing on a surface front slowly sagging into the area.  With such high CAPE, what goes up, must come down.  I wouldn’t be surprised to see an isolated severe gust or two, or a bit of hail.  The t’storms look pulsey & multi-cellular in nature in where they pulse up, belch out their downpour (Precipitable Water to 2″ tomorrow means 2″ per hour rainfall rates in a downpour) or their isolated severe gust/hail & collapse.  Then new scattered t’storms form nearby on their outflows.

If there was more mid & upper support, these would be organized, widespread severe storms with bows & supercells structures, but wind fields don’t support that at the moment.  I went for overall t’storm coverage at around 40% for the afternoon & evening periods.

These will diminish in the evening, followed by patchy, locally-dense fog tomorrow night-Wednesday morning.

4 Responses to “The Outlook………Your Storm Pics……& Re-Cap”

  1. Matthew says:

    Where did that large blob of rain come from in Illinois? Will it impact us today? Thanks!

  2. Chad Evans says:

    Hey Matthew!

    That MCS is largely on nose of overnight nocturnal low-level jet in combo with surface front & outflow boundary from our storms. Though LLJ is weakening & veering there, heating ahead of it should keep the front end re-developing through afternoon. That part will stay away from us. It is the outflow boundary surging out from the MCS northeastward that may pop a few storms for us today. Also, our northeast will get skimmed by a shortwave pivoting through the Great Lakes, which could pop a few storms. I like “isolated” & “25% coverage” for wording as of 11:45 a.m.

  3. Matthew says:

    Hello Chad! MCS is a better word choice than blob of rain! I appreciate your detailed response again, especially as I am a pilot trying to plan a flight later today with a rather undetailed federal forecast. One other question if you have time- you mentioned that it was riding a surface front. Is this another front moving around the low separate from the cold front last night? Thank you again! Matthew

  4. Chad Evans says:

    Thank you Matthew! It is the same front, but has largely been forced southwest by outflow boundary from our storms lastnight. Now, front is just southwest of area, but outflow boundary is lining up with cumulus in our southwestern counties.

    There are really two areas of agitated Cu at the moment, that is in our NE & our SW areas. Those will be the two zone of some storm development/occurrence over the next couple of hours.

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