BLOG: SEVERE WEATHER THREAT FRIDAY
Good morning...We'll get a break from the storms today....for the most part. Only a small chance for a pop up storm this afternoon and early this evening. 15 hour futurecast:
On to Friday.A cold front will approach from the west and the air mass ahead of it will be very warm and humid once again. While the setup for severe weather (large hail, damaging winds) is not super impressive, things may still get pretty active.The Storm Prediction Center has placed us in the "Slight Risk" area (yellow):
THREATS
The #1 threat from the strongest storms would be damaging wind gusts. Hail will be possible in the strongest storms but unlikely in any "run-of-the-mill" action. The threat for a tornado is quite minimal. Street and highway flooding and flooding in areas of poor drainage can't be ruled out but should not be a major issue.
TIMING
This is tricky. Most of our models show a couple of opportunities for showers and storms, even as early as mid-morning. The "outflow" from the rain can cause little pockets of cool air around that can act as a trigger for additional action. While it may rain at almost any point, the highest risk for SEVERE weather is probably after 2pm.9am simulated radar (NAM model):
5pm:
Remember that lightning is ALWAYS dangerous, severe thunderstorm or not. Make sure you have downloaded the Storm Tracker 21 app!
A complex of thunderstorms will miss us well to the west today and we can expect a partly to mostly sunny sky.
I can't rule out a passing shower or thunderstorm tonight.
Friday's thunderstorm risk is higher and there is also a threat for severe weather. This cold front is strong enough, will be plowing into plentiful moisture, and will be approaching at the "right" time of day that this will be a day to be "weather aware".The Storm Prediction Center has most of the region in the "Slight" risk for severe weather.
Of course we will have lost of updates over the next 48 hours.
Sunday looks gorgeous and dry. Highs in the upper 70s to near 80.
Temperature trends on the computer models show the weekend cool down but the classic mid July heat returns next week.
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LOADS of moist air east of the Rockies this morning. This map of the dewpoints screams "MID SUMMER!"
Highs today will be in the lower and middle 80s.
Heating up again next week.
Rain totals will average 0.05-0.15". Not a lot.
Here's what I am thinking as far as an hour-by-hour breakdown of the rain chances Monday:8am-2pm: 0%2pm-5pm: 10%5pm-7pm 20%7pm-8pm: 30%8pm-11pm 40%Remember, keep checking the forecast as this is not set in stone by any means.You can get a complete list of fireworks displays, parades, etc here:
I can't rule out a sprinkle or shower this afternoon as the atmosphere becomes slightly unstable. 15 hour simulated radar:
Highs today in the mid 70s. Enjoy!
Drier air will make inroads over the next 48 hours. Even as early as this afternoon and evening you will notice the air mass feeling less "sticky".
Highs today will be similar to yesterday. Will we hit 90 for the first time this season (officially)? It will be close.
The second of two cold fronts will cross the region tomorrow afternoon. This is the front that has the truly cooler air behind it. Not much moisture to squeeze out tomorrow but there could be a stray shower or thunderstorm in the afternoon.
Temperatures will stay in the 70s Tuesday and with dewpoints continuing to drop, it will be much more comfortable.
Rain totals over the next 10 are likely to be paltry. We are going to continue to see things browning out.
Beneficial rain did fall in the area, mainly from Youngstown south. Those with browning lawns in Trumbull and Mercer counties were not so lucky.
This morning it is pretty cloudy and muggy. Showers were to our south as of this writing (9:11am).
We expect there to be hit-or-miss showers through midday or early afternoon today. A thunderstorm can't be ruled out. Hi-res simulated radar:
A nice evening on the way with decreasing clouds. The lower dewpoint air that is to our northeast will mix in and it will feel less muggy late today and tonight.
Look for a hot and dry weekend. Dewpoints will come up enough on Sunday that it may be noticeable. Highs Sunday near 90. Hit the pool!
Violent supercell thunderstorms will likely develop this evening over parts of the Midwest and start tracking southeast. The storms will likely evolve into more of a "squall line" or, if you really want to get fancy, a "mesoscale convective system". You may hear "derecho" thrown around and that's fine.....call it what you want but the name does not matter. What matters are the impacts.Those impacts will be significant for our neighbors to the west.Simulated model radar taking us through early tomorrow morning:
Here's where the Storm Prediction Center has the risks today and tonight:
A reminder of (generally) what these categories mean.
Notice that Columbiana County is in the "Enhanced" category. I think this is reasonable as the odds of getting hit by the main line of storms increase as you head south and west away from Youngstown. I suspect that you will see SPC "tighten up" the gradient between the categories this afternoon, with areas north and east of Youngstown moved into the "Marginal" instead of "Slight" risk.I say that because I suspect the line of damaging storms will move something like this:
Odds of different types of severe weather (SPC forecast):
The window for severe weather in our viewing area (again, it's most likely south/west of Youngstown) will be roughly 2-5am.Hopefully we just get a good soaking rain, which we need. Models showing around an inch but keep in mind amounts can be locally much higher if soaking downpours persist.
This is one of those situations where things CAN change. Keep checking the forecast. These thoughts seem reasonable to me at 9:30am but as new information becomes available there can be updates to the ideas. Be sure you are following me on social media. 
A nice Summer day today with highs in the lower 80s.
Wednesday night? Potentially a different story. That warm front on the weather map will activate with severe thunderstorms Wednesday afternoon and evening in the Upper Midwest (Milwaukee, Chicago, etc). A complex of severe thunderstorms will roll east as we get past sunset.The question is: where does this complex go? It MIGHT bend right and be more of a problem for Columbus and Cincinnati. But if it DOES take more of a north and eastward track, severe weather would be likely to occur in our area Wednesday night.Storm Prediction Center outlook:
As you can see, the highest confidence resides in places such as Chicago, Fort Wayne, etc. There will likely be isolated tornadoes and lots of wind damage in that corridor. Large hail as well.A "low-level jet", or a ribbon of strong winds not far above our heads (3,000-6,000 feet) will be fueling these storms. Storms can pull down those winds (of 80+ mph) easily.
Here's just ONE model's depiction of the radar at 2am Thursday. This will be WRONG by some degree, it's just a matter of how much. Tens of miles or hundreds??
At this point, the weekend looks dry and steamy. Long-range temperature trends on the GFS and European models show plenty of warmth:
Along the leading edge of that tropical air mass, we have thunderstorms this morning in western Ohio.
These storms will weaken as they encounter the drier air over northeast and northeast Ohio. Still, we may get a residual shower this afternoon. Our hi-res model shows an increasing threat for thunderstorms as we head toward evening.
A "Slight Risk" of severe weather exists today in the western 1/2 of the Buckeye State. Storms could produce hail and damaging winds this afternoon. I am not concerned about severe weather locally although a "strong" storm cannot be ruled out this evening.
A more active day is on tap for tomorrow. A humid air mass will be in place and a cold front will approach. Not a washout but...especially in the afternoon, we expect a few rounds of wet weather.
Notice the cluster of heavier-looking storms on the NAM model over SE Ohio. That's where the highest risk of severe weather is Thursday afternoon and evening. We can't rule it out across the Valley but the odds of hail and damaging winds are lower here.
Behind it, a brief cool down for midweek.
Notice by Wednesday evening there will likely be some thunderstorms over parts of the Buckeye State. A couple of these can roam toward the Valley Wednesday night. Not impressed with the severe weather risk locally but central and western Ohio will be at risk. The Storm Prediction Center actually has an 'enhanced" risk area from Chicago to Detroit:
We have a higher risk of thunderstorms Thursday as an upper-level low pivots southward. This feature can bring showers and storms at any point Thursday and severe weather is something that is possible....especially south of Rt. 224.
Look at this stretch of weather in Phoenix. Yikes.
Here at home...here's a general guideline on what to expect. Mid/upper 80s for a few days Sunday-Tuesday.
Temperatures will return to the mid 80s Wednesday if we get enough sunshine. Dewpoints will be on the rise as well.
BACK TO BEAUTIFUL
VERY juicy air is off to our west and that moisture is set to head our way tonight and Saturday.
There could be a shower or thunderstorm along that warm front late tonight and early Saturday. The NAM model does not show much but it may be a bit underdone:
Most models show mainly dry weather Saturday afternoon with jist isolated pop-up storms.
Our cold front will approach Saturday night and that should actually be when the highest risk of thunderstorms is.We remain in the SPC "Slight Risk" zone.
Weighing the risks:
Meanwhile, a cold front will approach from the north and west.
Good setup for severe weather, right? Yes....but will storms actually fire? That's the million dollar question. As you can see in the image above, the model we showed on TV tonight has almost no activity firing ahead of the front. Some other models show a similar lack of activity. Some of the modeling is more "robust".A model profile of the atmosphere Saturday afternoon shows plenty of instability and some decent wind shear. This graphic is very complicated but I have circled (in white) the part that shows the wind direction changing from west-southwest to northwest as you go UP in the atmosphere. This is what we call "wind shear" and is one of the more important ingredients for severe weather.
This much simpler graphic shows the "energy helicity index" which basically combines instability (ability for air parcels to rise) and wind shear. There is a bullseye near or just east of the Valley.
Remember that, severe storm or not, lightning is ALWAYS dangerous. If you hear thunder, you are close enough to a storm to be struck by lightning. Head inside.
By the way, that early Saturday activity may be the key to what happens later in the day. If debris clouds stick around for a while after the rain ends (or the rain simply lasts longer), the atmosphere may struggle to "recover" to the point that it can produce tall, heavy storms. That's one of the big forecast challenges.
If you have not yet, please download the StormTracker 21 app in your app store of choice.More updates Friday.-Eric
"Slight" can be a deceiving word in these outlooks. When we are in a "Slight Risk" area, chances of severe weather are usually quite a bit higher than a typical day and you should be weather aware.What we may have is some damp weather to start and then a period of dry and hot weather. As we get deeper into the afternoon, storms may fire to our northwest and try to head southeast. The HIGHEST risk overall MIGHT be east of I-79 in PA but again...details we will work out in the coming hours.Weather For Weather Geeks will have more on this threat this evening and I will probably do a separate blog post as well.
Thankfully, today will be a calmer day. We are still under the influence of a deep trough of low pressure over southeastern Canada and that means the atmosphere can become a little unstable again this afternoon. A pop-up shower or thundershower is possible but it's only about a 20-30% chance kind of a thing. 15 hour futurecast:
It will be a cool, comfortable day today with highs only in the upper 60s to near 70.
Lows tonight will be in the 40s...keep those windows cracked! Great summer sleeping weather.
The Storm Prediction Center already has the area outlined for potential severe weather, which is somewhat rare this far out (day 5).
So this is obviously something we will be keeping a close eye on in the coming days.
What about the rest of the day? I don't think it rains MUCH. Pop-up shower and storm activity remains a possibility but I suspect there are many locations that do not see a drop for the rest of the day. 15 hour futurecast:
Hourly odds of rain in any one location:
Meanwhile, a cold front is approaching from the northwest. Notice the lower-dewpoint air behind that front. That's the refreshing air mass that we will enjoy tomorrow.
Friday will be a winner with highs near 80 and lots of afternoon sunshine.
Sunday will be an unsettled day but not a total washout. Plan on spotty showers all day with the chance for thunder as well.
Today looks TOASTY...a few degrees warmer than yesterday. Highs generally 87-88 with sunshine.
The weather map shows a front to our south...this marks the border between dry air (which we have) and moisture-laden air to the south.
That front will lift northward as a warm front tonight into tomorrow. Ironically tomorrow will not be as warm as today but it WILL be more humid.Speaking of tomorrow....a weakening cold front is on the way and this thing will struggle to produce MUCH wet weather. The threat is there at any time Thursday (with higher odds in the morning/midday) but the day will be FAR from a washout.Simulated NAM model radar:
Keep those outdoor plans but check the interactive radar on your StormTracker 21 app.
Sunday is a different story. While I do not think it will be a "rainy" day, I do think there will be showers and thunderstorms around on occasion. More humid as well.
This will make for a cool start to the work week with highs 66-70 Monday and Tuesday. Probably some "instability" showers around as well with all that cold air aloft.
