Isaac On the Move

The title that I've chosen for this post sounds like an oxymoron, doesn't it? Nevertheless, Isaac is still moving albeit slowly. In time, the remnants will make greater forward progress as the closed low opens up and gets caught up in the westerlies.

Until then, plenty of time to fine tune potential rain amounts for our region. I still believe the HPC is being quite aggressive as far as predicted rainfall totals.

This Thursday morning, I've noticed the axis of forecast heavier rain amounts shifting east. In fact, Louisville is included in a swath of 5-6" potential totals while parts of southern Indiana are in a zone of 6-8".

Remember, though, the QPF map shows the potential for these shaded areas to receive the forecast amounts. Not everyone will realize such totals. In fact, I think for most of Kentucky, the rainfall will be more scattered, not an all-day, all-weekend thing. However, the potential for 'training' bands will enhance rainfall totals in a hurry.

These amounts could prove beneficial as far as drought relief goes but a bummer concerning the holiday weekend plans and some potential flooding issues.

Keep abreast of the latest forecasts below:

Isaac QPF 

MS  

Isaac's Impacts For Kentuckiana

Have you seen the latest QPF map for the next few days? I downloaded a map at 8pm edt on Wednesday evening August 29, showing potential impacts for the region....

Hopefully, these numbers will not materialize for everyone. While the map showed widespread amounts of 7-10", don't expect ALL of these locations to receive these amounts.

I think the potential for heavy rains exist along the track; however, I also believe that Isaac will continue to be deprived of some of its moisture feed. Yes, the air will be tropical-like and any rains will be quite heavy at times. Based on past tropical systems, however, the main area of concentrated rains will be right around the center of the system. Scattered downpours will exist away from the center that may provide copious amounts of rain during 'training' episodes.

In other words, I think the map may be a bit aggressive in rainfall totals. However, some locations could realize some of these totals.

Also, look for a eastward shift in the heavy rain shield. I think Kentucky's amounts of 1-3" look good. 4-5" looks possible from Evansville IN to just north of Louisville KY, though. I think 6" is possible, but should be rare in Kentucky and southern Indiana.

More fine-tuning of Isaac's track will help determine who is going to get the brunt of the rainfall. Stay tuned.

MS

Taking A Trip...Along Interstate 5 (8/14/12)

When I'm not engrossed in weather, I enjoy taking a 'virtual' tour of areas that I find interesting. During my 'downtime', if that's what it should be called, I've been studying numerous towns and cities along our country's intricate web of interstates.

I chose to begin this adventure along the west coast of the United States, along the Interstate 5 at the northern terminus in Blaine, WA.

Blaine is located in Whatcom county and nicknamed 'The Peace Arch City'. Its motto is "Blaine is Where America Begins".

There are a number of interesting items and tidbits about Blaine. Here are just a few that I found noteworthy.

First, I found this fascinating historical tidbit. The town of Blaine was named after a U.S. senator from the state of Maine, James G. Blaine. Historically, he served twice as Secretary of State, was the 31st Speaker of the U.S. House of Representatives, and nominated President in 1884.

Interestingly, it was another Blaine that benefited the town more. During the period shortly after WWI, the National Prohibition Act (18th Amendment) was ratified, banning all sale and importation of intoxicating liquors. Therefore, smuggling of alcohol was rampant along the U.S/Canadian border. However, a Wisconsin senator (R) named John J Blaine wrote the 21st Amendment, which would later repeal Prohibition.

Next, I was intrigued by the Peace Arch nickname and what that was all about. From what I understand, reference is made to the International Peace Arch that was dedicated to the centennial of the signing of the Treaty of Ghent in 1814 (see Treaty of Ghent). It was dedicated in 1921.

Today, the Peace Arch represents the tri-lateral friendship between Britain, the United States, and Canada. Standing some 67 feet tall, it represents the longest, undefended boundary in the world, nearly 3000 miles long. One foot in American soil and one foot in Canadian soil, the Peace Arch is a must-see for any tourist/visitor. For more historical information, please click here.

Finally, a geographical point of interest that I have yet to come across. Have you ever heard of a spit? Well,, Blaine has one of those called the Semiahmoo Spit. I provided a Google Satellite map of the area here. Hotels and a park can be found along this attraction

According to a popular reference, a spit is a type of deposition landform also called a sandspit. It is caused by a process called longshore drift that transports sediments along a coast at an angle to the shoreline, dependent on additional factors such as backwash and wind direction.

Other spits include the Provincetown Spit on Cape Cod, Massachusetts and the Dungeness Spit that we'll cover in a future series, as it is located in Washington state.

Access more info below....
Spit caused by longshore drift
What is a spit?

Please continue to follow my journey along the I-5 in a soon-to-be-released segment....

MS

More Severe Weather Chances

4:55pm edt Update
Bloomington IN - some trees down, including blocking roadways. Also power lines down in some areas as well.

K-index vals a bit higher toward the Ohio river just north of Louisville. If line of storms can make it this far, the strongest storms look to stay just north of Louisville. That's a big 'if'. Instability looks to be waning across the region with LI's around -4 to -5, up from -7 to -9. CAPE vals also are becoming more stable. If storms don't make it to the river by 7pm, we'll probably stay dry for the rest of the night.
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A severe thunderstorm watch is currently in effect for just a few counties of north-central KY while most of southern IN is included in the box.

Keep up with the warnings below...

Damaging wind is the primary threat and large hail a secondary threat.

MS

Severe Weather Under Way....w/Updates

In Jefferson county Pennsylvania near Dubois, hard hit by severe weather. "...total disaster, trees and poles down everywhere."

This is just a sample of what several locations may be dealing with this afternoon and evening. We are in Nowcast mode. Reports of severe weather will be coming...

Jefferson county PA radio here.

Widespread Severe Weather Potential(UPDATE)

3:15pm UPDATE
Watch box is extension to first watch. The newer box goes all the way back into Missouri. Scattered cells are developing in a very warm and moist environment. Currently no warnings. However, these cells are rapidly developing. DCAPES are increasing. The newer watch holds out moderate risks for high winds and hail whereas the first watch has high risks for these. At this time, convective debris in the form of cirrus clouds and cumulus may try and inhibit rapid intensification of storms near Louisville initially. However, am expecting a line to form and push through the area between 7 and 9 pm edt. These could become severe.
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2:55pm UPDATE
In addition to Watches for Ohio and northern KY, a new Watch has just been posted that includes the Louisville area till 10pm edt. So far, no warnings with this new Watch yet. I'll post probabilities from the SPC watch box shortly....
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The most recent update from the SPC is as follows:

* Heating already in place
* Moisture readily available
* Boundaries from prior convection will aid in future development
* Winds aloft will enhance storm initiation and subsequent bowing segments

The main areas that could see widespread wind damage remain the same as previous forecast, from Cincinnati to the New England states. These areas are under a MODERATE risk for severe weather.

High-end slight risk still resides close to Louisville area and the northern quarter of Kentucky east of I-65.

Things to look out for:
)Severe Thunderstorm Watches will be forthcoming soon for several locations from northwest to southeast. Look for Watches to come out for the New England states and areas of Indiana and Ohio. Later, expect Watches for parts of Kentucky.

)Strength of winds aloft

)Where leftover boundaries interact, in order to determine possible storm development and progression

)Hard to imagine, but convective debris and miscellaneous precipitation could diminish severe potential. Right now, that looks like a small chance

)Winds in excess of 55 mph possible near Louisville while winds in excess of 70 mph near Cincinnati and northeastward.

I'm sure more updates will be forthcoming throughout the day.
Stay tuned....

MS

A Major Wind Damage Event Increasingly Likely(UPDATE)

2:00pm edt UPDATE
As expected, a MODERATE risk for severe thunderstorms now exists across parts of the Ohio Valley to parts of the northeast for Thursday. Also, a high end slight risk now exists for areas along the Ohio river. Main threat will be a possible derecho with widespread wind damage and power outages.
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A large swath of US real estate could be in line for severe thunderstorms on Thursday. The most recent SPC update shows the greatest concern from southern Ohio to western/northern PA into central NY. In fact, the widespread severe potential may lead to a moderate risk assessment for these areas.

The next update will be between 12:30 and 1:30 pm edt (1630z and 1730z).

I'm also looking at a SWd extension of high end slight risk for areas along the Ohio river, including the Louisville Metro.

Follow the latest SPC updates here.

MS