Chad Evans

4 P.M. Update

September 1st, 2014 at 4:09 pm by under Uncategorized

A few scattered showers/t’showers are passing through the viewing area now.

The actual surface cold front is just northwest & west of the viewing area.  Here, a band of towering, agitated cumulus is noted, so we will still watch for potential narrow squall line to form.  Isolated severe threat still seems reasonable.

With it paralelling the flow aloft, it may train some.

Also, a lot of t’storms will likely develop in Missouri to Illinois.  That mass of t’storms will tend to move east & northeastward tonight bringing showers & t’storms to the area.

Locally-heavy rainfall still seems to be a good call south of U.S. 24.

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2:15 P.M. Update

September 1st, 2014 at 2:27 pm by under Chad's WLFI Weather Blog

Squall line continues to develop & sweep through Michigan with watch & warnings.

Here, agitated cumulus are noted in bands just ahead of the cold front as skies clear some in our western counties with erosion of surface cap (CINH).

Still expected line of storms, but only “isolated severe”  seems reasonable rather than “scattered severe” owing to extended period low clouds have resided in our area.  This has kept temperatures & instability down.

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12 P.M. Update

September 1st, 2014 at 11:51 am by under Chad's WLFI Weather Blog

SURFACE COLD FRONT………

Surface cold front runs from Chicago to St. Louis at the moment with lots of low stratus across the area underneath low-level capping (inversion).  Outflow boundary is also progressing through area from the severe weather well west of here last night.  A few showers/t’showers are possible at any point this afternoon as boundary slowly progresses through area.

CINH & LOW STRATUS CLOUDS………

Thinking this capping will wear off & the sun will appear this afternoon.  With already 1000 J/kg of surface CAPE (given current dew points as high as 76!), once the sun appears, this may soar to 2500 J/kg, but it doesn’t look as unstable as it did yesterday (4000 J/kg).

“ISOLATED SEVERE” RATHER THAN “SCATTERED SEVERE”……….

Stronger wind fields aloft will support more organized storms, but I prefer to keep the wording “isolated severe” rather than “scattered severe” due to less instability expected & just so much low cloudiness lingering on into the afternoon.

This said, short, high-resolution models support storm development along cold front.

SOME LOCALLY-HEAVY RAINFALL POSSIBLE (BEST POTENTIAL SOUTH OF U.S. 24)………….

This would tend to occur this evening, followed by considerable t’storm activity north of the front overnight.  This could dump locally-heavy rainfall.  Given wet soils, some localized flash flooding is possible.

It looks like the best potential of this is south of U.S. 24 where some +2″ rainfall amounts are possible.

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A Wet August! Hot & Humid with More T’Storms In the Forecast

August 31st, 2014 at 11:05 pm by under Chad's WLFI Weather Blog

LABOR DAY WEATHER HISTORY:

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It was one wet August over much of the viewing area.  There were a few local exceptions, but by & large totals were above to much-above normal for the month.

Parts of Newton, Jasper, White, Pulaski & Tippecanoe had one of, if not, the wettest August since 1895.

At West Lafayette, August 2014 will go down as the 4th wettest since 1887 in the Purdue/Purdue Ag Farm data set (in process of archiving the records back to 1879):

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The heaviest totals, per Doppler radar, ran across northeastern Jasper to Pulaski County & then in a couple of bands from southeastern Jasper, across White County.  Yet two other areas of very heavy rainfall appear to have occurred in north-central Benton & northeastern Tippecanoe counties.  These areas appear to have picked up over 10″ of rainfall for the month.

Below are measured rainfall totals for the month per NWS COOP, AWOS/ASOS, Mesonet, CoCoRaHs & WLFI stations.

DMA Map IIII

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A few showers/storms may pop at any point during Monday as outflow boundary from tonight severe event to our west passes, but coverage will tend to run 20-30%.

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However, a squall line may affect us in the evening.  It may train some & with some lingering rain/thunder behind it into the overnight-early Tuesday morning, it is possible that a few locations may see +2″ of rainfall.  As usual, rainfall amounts will vary in the area, however, from 0.60″ to +2″.

Friday-Sunday morning 4.40″ of rainfall fell in Kentland & 5.00″ fell in parts of Benton County.

This said, given the wet August anyway & the t’storms on the way, the potential exists for some flash flooding Monday evening-night.

Scattered severe wind gusts are also possible with it & perhaps a bit of large hail.

With better wind fields aloft, these storms look more organized & longer-lived than the pulsey storms with isolated severe weather as of late.

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Perfect Summer Day!

August 31st, 2014 at 5:09 pm by under Chad's WLFI Weather Blog

It is a perfect summer day with cumulus, sun, nice breeze & dry weather.

It is humid, but typical of an Indiana summers day.

DMA Map III

 


1:43 P.M. Update

August 31st, 2014 at 1:31 pm by under Chad's WLFI Weather Blog

2-day rainfall totals:

DMA Map II

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Only 0.30″ of rainfall fell last night at the Purdue Airport, but the Ag Farm received over 1″.

Kentland was the highest total reported from any spotter with

After highs yesterday of 81 to 88, today will will rise to 82-87 with skies becoming partly cloudy.

It will still be humid, despite passage of weak cold front.

Front will move back northward tonight with clouds (kept it dry) with lows near 70.

Tomorrow will heat up with highs of 85-90 with high humidity.

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Storms are likely Labor Day with the best potential in the evening.  There will be a lot of dry hours & it will be hot & humid & rather breezy, but data favors a squall line late in the day.

So, thinking squall line will blow up Minnesota to Kansas this evening with severe weather there, then weaken.  The outflow boundary may pop a few storms at any point tomorrow in our area with 20-30% coverage as it passes.

However, the squall line would tend to pop in Illinois in the mid to late afternoon & move eastward, tending to affect us in the evening.

This situation is different compared to recent rounds of storms.

The stronger mid & upper flow will actual move farther southward & overspread 4000 J/kg of surface CAPE Monday afternoon-evening.  The past several rounds have had the wind fields north of our area with generally pulse-type storms with isolated severe wind/hail threat.

The instability in tandem with the better wind fields points to an organized line of storms with scattered severe wind & hail along the line, not just pulsey, isolated threat.

Locally-heavy rainfall is possible given the high dew points.  Local flash flooding is possible, given recent heavy rainfall & the inability for soils absorb high rainfall rates (due to all of the rainfall fall over the past few days to couple of weeks).

For afternoon lower atmospheric profile, I selected the Lafayette grid point, but it is a good representation of the entire viewing area.

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It still looks hot September 5 to around the 9 with the potential of 90 or more.

After the hot, humid weather, a more early-fall regime will set up after September 10 with some low temperatures in the 40s with a few days of highs only near 72.


11:18 P.M. Update

August 30th, 2014 at 11:20 pm by under Chad's WLFI Weather Blog

Southern low has made it to Tennessee, but it continues to create juggerknot in not allowing our front to make rapid progress to the southeast.

In fact, even as of 11:18 p.m., front is just now coming into Benton & White counties!

With the slow movement of t’storms & training, up to 2″ of rainfall has occurred in some spots in these counties.

T’storms will continue to move southward with front, but it will take time.

Figured we could drop coverage to 25% overnight with the storms by 11 p.m., but they are holding together nicely with good convergence on the front in unstable airmass, so 40% seems to be needed for the viewing area as a whole for tonight.


8:07 P.M. Update

August 30th, 2014 at 8:12 pm by under Chad's WLFI Weather Blog

Surface cold front runs from Denham to Rensselaer to near Earl Park with broken line of storms along.

These are slowly moving into Benton County & eventually White.

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5:30 P.M. Update

August 30th, 2014 at 5:31 pm by under Chad's WLFI Weather Blog

Actual surface cold front remains active with at least broken line of storms, but it hasn’t moved since midday.  This is likely in response to developing surface low in the southern U.S. backing the flow to prevent a more southeasterly movement of the front.

It is currently over northern Newton & Jasper counties with t’storms & isn’t moving.

It will get the boot southward tonight, but t’storms will gradually fade with southward progression, it appears.

Nonetheless, will keep 35% pops for this evening & 25% pops in for tonight.

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11:55 A.M. Update

August 30th, 2014 at 12:02 pm by under Chad's WLFI Weather Blog

After morning scattered showers & t’storms (it poured over West Lafayette, but only sprinkled in downtown Lafayette), we are now in a lull with some sunshine & soaring temperatures.  It is 81 as of 11:55 a.m. with a dew point of 71, but the south wind at 10-15 mph makes it feel better.

Actual surface cold front is approaching I-57 in Illinois.  A few new showers & t’storms are just starting to develop ahead of the front.

Thinking more scattered t’storms will form along & ahead of the front over the next 1-2 hours.

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