Sunday, July 19, 2015

Heightened Alert Status for Northeastern Kentucky

Although no widespread damaging thunderstorms on a regional level is expected, far northeastern Kentucky is part of a region which includes southern Ohio that has a bullish signal for severe weather Sunday.

Yesterday there was a handful of wind damage reports generally from Rowan and Fleming counties.

However, at this point, the SPC has not elevated any 'major' risk for the northeastern part of the state. But, analogs for that region do show an average ranking of 5.6. Anything ranked below a 7 means severe weather likelihood increases.

Again, just a heads up. There is a heat ridge that these storm complexes love to ride along. In addition, a front will be getting closer to the region and any leftover boundaries from early morning convection may set the stage for primarily afternoon development.

MS

Tuesday, July 14, 2015

Water Logged and Storm Weary

Another round of heavy rain is possible today, affecting communities that have seen too much rain already.

Frankfort has already recorded its 7th wettest July on record...a sloshing 7.88"  and we are only at the halfway point of the month (almost).

Louisville and Lexington are closing in on their top ten wettest July's.

In Louisville, MSD automated rain gauges show some locations receiving 8-10" for this month. St Matthews has seen 8.94" while the Billtown Pumping Station in southeast Jefferson County has 9.94". Amazing!

Storm ravaged areas coupled with too much rainfall may be causing residents to display the white handkerchief fairly soon.

One Mesonet site in Harrodsburg recorded a 74 mph gust this morning while 50-65 mph winds were common elsewhere with these severe episodes.

Though not expecting a widespread issue today, I would expect a decent amount of storm reports today. Stay safe everyone.

MS


Monday, July 13, 2015

SQUALCON Watch Today and Tuesday

UPDATE 4:35 pm
Well, other than some heavy rain, not much else to report on from here in SW Jefferson County. Been surrounded by several warnings but nothing significant from this first round.
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UPDATE 3:30 pm
Went to a different spotting location this time, still did not find anything worth reporting. However, new cell poised to move into the area. Don't yet know if rain-cooled air will choke the wind threat. Will just report from my house this time.
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UPDATE 1:05 pm
High-end Severe Thunderstorm Watch issued for much of our region. Widespread wind damage and power outages possible. Moderate (60%) chance for at least one wind report of near hurricane force. Upgrading SQUALCON Index to 4.6.

UPDATE 12:30 pm
60-65 mph winds common along this line.
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UPDATE 12:20 pm
Wind damage reports coming in from Indianapolis...NEW watch to be issued for Louisville and surrounding locations in a few minutes.
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UPDATE 11:45 a.m.
Storms reaching Indianapolis...Looking at camera shots
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UPDATE 11:10am
SPC shifts severe threat farther west. Current radar shows possible beginning of a bowing line northwest of Indianapolis. If this line holds together, could the center of the bowing line track just west of Louisville between 2 and 3 p.m.?
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The threat for severe weather with widespread, yes, region wide, damage is expected today and into tonight for some of us. Tuesday's severe threat may include a higher tornado risk, especially across eastern Kentucky.

I am assigning a SQUALCON of 4.4 for our region of Kentucky today with several areas reaching wind speeds that will exceed 55 mph. In fact a possible derecho may occur if it meets specific criteria.

Think of a derecho as a wind avalanche. A typical avalanche feeds on a rapidly accelerating collection of snowfall that covers a great distance down a mountain side producing enormous momentum. Similarly, a derecho feeds on a collection of recycled atmospheric processes accelerating wind speeds over a great distance and creating enormous momentum thus widespread damage along its path.

Looking at the progression of a derecho on radar is helpful. The typical bowing out line segment (outflow) with a rain shield wrapping around and into the center of the bowing line (inflow on back side) shows where the strongest or most damaging part of the storm exists.

The last derecho that affected the region was exactly 11 years ago. That one had winds exceeding hurricane force along the leading line and produced tremendous damage.

Therefore, I may increase the SQUALCON value to a rare 5.0 if it appears that the 'avalanche' of wind will likely occur.

Timing these storms can be problematic. Once the cluster forms far to the northwest today, the line will gain momentum or forward speed. So, we'll have to wait and see if a cluster forms first and try to time the main line's arrival.

Otherwise, it is possible that storms may fire up ahead of the main line thus dirtying the line's forward momentum some. But it still looks likely that damage will occur anywhere along that line.

Flooding appears to be a threat as well. Many Kentucky and Southern Indiana residents have seen too much rainfall this month and last month as well. This will only make matters worse.

Tuesday looks to be a violent day for many in Kentucky. Perhaps the greatest threat resides along and east of Interstate 65. Let's get through today first.

MS

Sunday, July 12, 2015

SQUALCON Watch for Monday

UPDATE 1:00pm edt
Preliminary look at Tuesday's severe threat may be higher than Monday's. Huh??
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First, this morning's light show is very impressive as I look to my north in the waning night sky. This complex of storms does indeed pack a punch of pure power with plentiful pops of lightning. Heavy rain and dangerous lightning look to be the primary threat.

As far as severe threats go, there could be isolated reports today but am not concerned about widespread issues except for flooding.

My focus is for tomorrow, Monday, July 13. An increasing probability for widespread severe weather has bombarded me from all directions.

Therefore, I am issuing a SQUALCON Watch for Kentucky tomorrow. Any value above 3 on a scale of 1 to 5 indicates an increasing likelihood for severe weather, especially on a regional level, as a cluster or squall line of storms is expected to impact the region.

I have good reasons to elevate this threat. Current value is already approaching a 4.0, which represents widespread damaging wind threats. Supporting evidence includes:

Analogs - The top 5 ranked analogs out of 15 that affect us on a regional level average out to 7, and this is still outside of my normal timeframe for consideration. Any average ranking of 7 or lower represents a bullish stance for widespread severe thunderstorms.

SPC has placed much of the region in a Moderate Risk shading for Monday.

Also, I forgot to mention that one of the analogs is from a storm complex dated July 13, 2004. Anyone in the weather circle will recall that date of the Derecho of 2004.

Local NWS office in Louisville is raising awareness of the impending possibility of a widespread event.

Stay tuned to local media and have those programmed weather radios ready.

MS