Severe Threat Potential Looms on Friday

Good afternoon, the latest update from the Storm Prediction Center is in and instead of doing the afternoon update, I’m going to combine it all in one large blog post, this may be a bit on the long side, so bear with me.  We are going to break down some of the larger cities that’s under each of the categorical risk.  The entire state is under the gun for severe storms on Friday, so everyone need to be weather aware tomorrow.  The following cities/locales are under the enhanced risk…Evansville, Jasper, Bedford, Madison.  The following cites are under the slight risk, Indianapolis, Anderson, Muncie, Bloomington, Terre Haute, Richmond.  Finally, these cities are under a marginal risk, South Bend, Fort Wayne, Kokomo, Lafayette, Gary.  Now overall for the state, an enhanced risk of severe storms is possible for southwest and south-central Indiana, with a marginal risk for central Indiana, and a marginal risk for northern Indiana.  Slide15

***Potentially a significant severe weather event is possible, especially in the enhanced risk area***  Showers and thunderstorms will be ongoing Friday morning and we won’t how the morning storms will play in the afternoon/evening severe weather, but right now, conditions are in place for a rather active afternoon/evening.  A new round of showers and thunderstorms look to develop during the afternoon hours and move southeast.  Initial storms may be supercellular in nature and could produce very large hail (up to and possibly slightly over 2 inches in diameter), damaging winds, and isolated tornadoes, before storms congeal into line and bowing segments, when damaging winds will become the primary threat, but large hail, and isolated tornadoes will also be possible.  The severe threat may wind down by the early to mid evening hours, but chances of showers and thunderstorms will remain in the overnight hours.  Following graphics is what the FutureCast radar predicts from 1 am to 8  pm Friday.  Errors in timing between 1 and 2 hours either way…

We are going to end this blog with potential hazards, beginning with the enhanced risk area.  All modes are in play, including the risk of isolated tornadoes, but damaging winds, and large hail, some possibly over 2 inches in diameter will be possible.  Within the slight risk area, I also think that all modes of severe weather are possible, with damaging winds and large hail being the primary threat, but isolated tornadoes may also be possible.  Finally for the marginal risk area, damaging winds and large hail will be the primary threats, but can not totally rule out a tornado or two.

To end this blog, I will say what I normally would say, there’s a lot of uncertainties in regards to the overall severe weather potential, we have seen where conditions dynamically looked favorable, little or no severe weather occurred.  This could very well happen again tomorrow.  The keys is again how the morning convection, how fast it can move out of the area, and whether we see strong surface heating, if the sun can remain in check and we are dominated with cloud cover, then the severe threat will be limited, however, areas that end up seeing prolonged sunshine and strong surface heating, then those will be the areas that will most likely see the severe weather.  The best you can do is remain weather aware, follow the safety tips below, have a plan of action in the event of warnings, and we will get through tomorrow together, whether severe weather occurs or not.  As far as coverage, we will likely begin coverage as the morning storms move into the state, likely during the overnight hours around 1 or 2 am and we will continue until the severe potential is over.  Tomorrow will be declared a “Weather Alert Day”.  Updates will be available on our Facebook page.  Slide51

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Isolated Strong to Severe Storms Possible This Afternoon

Good morning, the Storm Prediction Center has placed east-central and southeast Indiana under a marginal risk of severe storms this afternoon.  So what I wanted to do is produce a quick blog on what we could see today and overall, the risk is not that great.  While we will have plenty of instability, shear is really lacking and will only be 20 kts or less and you need at least 30 kts or more of shear for ideal severe storm development.  A cold front will provide the focus for storm development this afternoon and motion with the storms will generally be southeast today.  The graphic below shows the areas under the marginal risk (there will be an update from the Storm Prediction Center around 9 am)Slide15

So taking a look at what FutureCast shows, showers and thunderstorms will begin to develop sometime after noon, and this could very depending on when the cap erodes.  We expect a broken line of storms to move southeast through the afternoon hours, it will not be widespread showers and thunderstorms, in fact some areas may not see any rainfall today, but areas that do see storms, especially in the east-central and southeast counties, could see heavy rainfall, and again that potential for isolated severe storms.  We expect by 4 pm the line to be along a Lafayette-Kokomo-Marion line, moving along a Crawfordsville-Anderson-Muncie line by 6 pm, and a Terre Haute-Indy-Richmond line by 7 pm.  After 8 pm, as daytime heating is decreasing, the storms should begin to weaken and by 10 pm, most of the storms should have dissipated, with only isolated storms possible for southern counties.  This timeframe is not etched in stone and there could be variations of this timeline, so error plus or minus an hour.

 

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Finally, the Severe Threat Index, we are not expecting widespread severe weather, most of the area under the marginal risk will likely not see any severe storms, but for those who are under the marginal risk, just keep an eye on the radar throughout the day, we will have updates on the Facebook page throughout the day.  If any storms do become severe, damaging winds will be the primary threat, some of the most intense storms could produce hail, but that potential is very low.  Heavy rainfall will be possible with any thunderstorm, but widespread flooding is also not likely, could see some ponding on roadways and minor flash flooding in poor drainage and low-lying areas.  Overall, again, just keep an eye on the radar throughout the day, this will not be a widespread threat, most of the day should remain dry, and in fact, some areas may not even see any rainfall today.  Stay weather aware and have a great Tuesday!Slide16

Alberto to Bring Heavy Rain, Severe Weather to Indiana

Good afternoon, before getting to the impacts that the remnants of Alberto will bring, let’s take a look at where Alberto is currently.  As of this typing, Alberto is located about 25 miles northwest of Birmingham or about 417 miles south-southwest of Indianapolis.  Alberto is moving to the north at 12 mph and maximum sustained winds are near 30 mph.  Alberto is currently producing heavy rainfall across northwest and central Alabama.Slide4

Alberto will continue to move north to north-northwest through the rest of today into tonight and will move through the Tennessee Valley through the day and move into the Ohio Valley during the day on Wednesday as Alberto will begin to turn to the northeast.  Some of the most outer rainbands will move through southern Indiana this afternoon and evening and the core of Alberto’s remnants will move across the state during the day on Wednesday.  The area that have the potential of seeing the heaviest rainfall will be on the north side of the storm.  The core of Alberto will be affecting the southwest counties Wednesday morning and spread into the Indy area by lunchtime and northern counties by the early evening hours.  Futurecast radar will show the evolution and movement of Alberto and will run from 2 pm this afternoon through midnight Thursday.

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In addition to the heavy rainfall potential on Wednesday, there is the potential for severe weather as well.  There is a marginal risk of severe storm for the northeast half of Indiana, where isolated tornadoes and damaging winds will be the primary threat.  As the core of Alberto moves across the state, areas that will be in the northeast quadrant will be under the highest potential of seeing severe storms.Slide12Slide15

Finally, how much rain will fall, here is a couple of models that show what will fall, the first model is an in-house model that I think is under doing the total rainfall as this model is showing less than an inch of rainfall through midnight Thursday.  Again, I think that this model is under doing the amount of rainfall that could fall.Slide5

Next is the NAM 3km model rainfall potential through 2 am Thursday.  This models is a bit closer to my thinking with widespread areas in excess of an inch across the state, with pockets of 2 to 3 inch rainfall totals.  NAM 3km

Finally a look at the GFS, rainfall totals again looking a bit lower than my thinking of rainfall will eventually end up being.  GFS for much of the state is showing an inch or less through 2 am Thursday. GFS rainfall

So my thoughts for rainfall.  I think that western Indiana will see the highest rainfall totals between 1 and 2 inches, with isolated totals of 3 to 3 1/2 inches possible.  Eastern Indiana will likely see closer to 1/2 to an inch of rainfall, with isolated totals of up to 2 inches.  Flash flooding will be possible as this final graphic shows, that there is a marginal to slight risk of excessive rainfall for southern Indiana this evening and tonight.  A slight risk for excessive rainfall for the entire state on Wednesday, flash flooding will be possible and flash flood watches are already posted for far southern Indiana counties and we will see if watches will be expanded north.  Stay weather aware on Wednesday.  wpc day 1wpc day 1

 

Isolated Severe Storm Potential Saturday

Good afternoon, taking a look at current conditions across the Ohio Valley, clouds are beginning to increase across the area from Indiana eastward to Ohio, lots of clear skies in West Virginia.  Temperatures are generally in the 40s and 50s across the Ohio Valley.

Taking a look at FutureCast from 4 pm this afternoon through 7 am Saturday morning will showers and embedded thunderstorms begin to increase in coverage and in some cases intensity.  Showers will begin to move into Indiana in the early evening hours and thunderstorms may enter into the picture between 7 and 9 pm.  Showers and embedded thunderstorms will continue to spread eastward and move into western Kentucky and Ohio by the late evening hours into the very early morning hours of Saturday morning.  Showers at times may be heavy and some of the stronger storms may produce gusty winds and small hail.  Heavy rainfall will move into the Cleveland area by 2 am and around the same time, some lighter rain will begin to move into western West Virginia.  Showers and storms will begin to become more scattered about for Indiana.  By 5 am, heavier rain will move into the Charleston area and by the end of the period will move into eastern West Virginia, while more scattered showers and embedded storms will continue for much of Indiana, central Kentucky, and western Ohio.

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Heading into Saturday, there is a marginal risk of severe storms for much of central and southern Indiana, much of Kentucky, and southwest Ohio as a cold front approaches the area.  While there will be lack of instability with this cold front, dewpoints will increase in the upper 50s and a strong low level flow will be sufficient enough for thunderstorm development, in which a few storms could produce damaging winds.  This will not be a widespread potential by any means, and most areas will not see severe weather, but anyone within the marginal risk area could see isolated damaging winds.

We will continue to monitor the situation even we are not anticipating a widespread event.  For further updates, please like the Equinox Weather Facebook page.

Severe Weather Potential for Sunday

Good afternoon, before we go into details with the severe weather potential for Sunday, we will take a brief look at the current conditions as of this write up.  Warm front as of 11 am is now in southwest Indiana and this front will continue to push northward.  Showers on radar across northern Indiana, with heavy rainfall from near South Bend to Walkerton.  Temperatures are ranging from a cool 43 in South Bend and Elkhart, to a mild 64 in Evansville, Washington, and Jasper.

Looking ahead to Sunday, a strong cold front will continue to march east and southeastward across the Central Plains and will be in a position from central Wisconsin to eastern Iowa to northwest Missouri by Sunday morning.  Showers and thunderstorms could be ongoing as FutureCast will show below.  As of the 1:30 pm Convective Outlook from the Storm Prediction Center, an enhanced risk of severe weather is for all of central Indiana and a small portion of northern and southern Indiana.  A marginal risk of severe weather for extreme northern extreme southern Indiana, with a slight risk in between these area.  It is of a quick note that the threats have been pushed southward a bit, and the southward push could continue depending largely on which areas will be in the warm sector.

Now what is causing the severe weather potential is a strong cold front that will sweep through the area on Sunday afternoon through early Monday morning.  Bulk shear by Sunday evening will range from 35 kts in southwest Indiana to an incredible 80 kts in northwest Indiana, that is plenty of shear to maintain thunderstorms.  Winds at 5,000 feet will range from 20 kts in northwest Indiana to around 45 kts in southern Indiana.  Lapse rates in excess of 7.5 also suggest the potential for very large hail.  However, the exact location of the warm front, and extensive cloud cover and the possibility of a cap being in place can also limit the overall severe weather potential.  Supercell thunderstorms, some semi-discrete could develop during the afternoon hours, and some of those storms will produce all severe weather modes, including a few tornadoes, especially near the location of the warm front, then the storms will congeal into one or more lines of strong to severe storms, where damaging winds, and a brief spin up tornado or two will be possible.  The main threat for those in the enhanced risk area will be large hail and damaging winds, but again a few tornadoes will be possible and the hail may exceed 2″ in diameter.  For the slight risk area, large hail and damaging winds will be the main threats, but can not rule out an isolated tornado.  In the marginal area, large hail and damaging winds are the main threats, but there is also a non-zero risk of an isolated tornado.

Finally looking at FutureCast radar from 4 am Sunday through 4 am Monday morning, showers and thunderstorms may be ongoing near the vicinity of the warm front, some small hail and brief heavy rain may be possible with these storms.  Some of these storms may also play a role in the overall severe weather potential as well.  Stronger rounds of thunderstorms will begin during the early to mid afternoon hours, first starting in Illinois, then moving into Indiana.  It will be some of these storms that will have the potential to become severe.  As we head into the evening hours, showers and thunderstorms, some still could be severe will continue to move ahead of the cold front and with the loss of any daytime heating, these storms will eventually begin to wane slowly after sunset, moving into southern Indiana after midnight.

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Even if the severe weather do not play out as we are expecting it to and that is still entirely possible, heavy rainfall will still be possible with any thunderstorm, and to prove that point, here’s two model solutions of possible rainfall through 7 am Monday.  The GFS is a bit conservative, but still suggesting 1 to 2″ across much of the state.  The NAM 3km model I think might be a little too aggressive at least in the rainfall totals, but as FutureCast showed, most of the heaviest rain will focus on central Indiana, where the model suggests anywhere from 1.5 to 5.25″ of rainfall.  Even the conventional NAM is suggesting over 4″ in east-central Indiana.  Localized flooding will be possible in any of these scenarios.

So to conclude, we are still looking at the potential for severe weather on Sunday, there still remain a few uncertainties that will be answered over the next 12 to 18 hours.  Right now, the area that could see the greatest impacts will be central Illinois and central Indiana, as things have trended a bit more southward.  Heavy rainfall will be possible, even if severe weather do not occur and localized flooding will be possible.  Finally, even though I haven’t mentioned it above, even outside of thunderstorms, winds could gust up to 30 mph ahead of the front that could knock down some branches.  Stay weather aware for Sunday and be sure to keep tuned to the latest information on the Equinox Weather Facebook page.