BLOG: Has it REALLY Been a Cool, Wet Summer?

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So, the Summer of 2014 has been unusually cool and wet, right?? Part of that statement is true, depending on where you live. In some parts of the Valley, it HAS been wetter than average since June 1. But temperatures? When we look at the average since June 1...it's really not much of a story at all.Let's take a closer look at the numbers. At the Youngstown-Warren Airport (the OFFICIAL reporting station for our area), the stats since June 1 look like this: junjulNotice that at the airport, rainfall has been almost EXACTLY average since the 1st of June. Also notice, temperatures have been slightly ABOVE average for the 52 days as a whole.On the subject of precipitation, amounts have been quite variable in the WFMJ viewing area...which is typical of Summer. Some places get a couple of soaking storms that drive up rain totals locally. In some communities is HAS been a wet Summer. A sampling of rain totals: raintotalsYou can also see what areas have been wettest since early June on this map, which shows satellite-estimated totals:   preipmapNotice the wet spots in Mercer and Columbiana counties.Temperature wise, the perception is certainly out there that this has been a "cool" Summer. I think this is mostly due to the lack of sustained hot periods and the lack of 90+ temperatures. AND, July has been a below average month: julyFor the Summer (June 1-now) this has been the 41st coolest Summer since 1930. Not a stat that jumps out!summerranksAnother cool shot on the way next week. Thanks for reading!Eric

BLOG: What Do Those Percentages on the Forecast Graphic Mean??

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One of the commonly misunderstood parts of a weather forecast is the "probability of precipitation", or PoP. It is so frequently misunderstood that some television meteorologists do not use them.At WFMJ, we DO use them and part of the purpose of this post is to show you WHY.First of all, what does a 40% chance of rain ACTUALLY mean? Let's start with what it does NOT mean:1) 40% of the area will get rain2) It will rain 40% of the timeWhat it actually means is that there is a 40% chance of measurable precipitation occurring at any point in the day at any location in the viewing area. The main reason we use PoPs at WFMJ is because it is a way to communicate graphically what a day will be like. Let's use this coming weekend as an example. Here is our current 7-day forecast WITHOUT PoPs included: nopopsOK, POP QUIZ. Based on that graphic, which weekend day is likely to be the wetter of the two???? Another way of putting it: which day are more backyards likely to get wet at some point in the day?Unless you are listening intently to what the forecaster is saying while this graphic is on the screen, there is virtually no way of knowing the answer. The icon looks pretty much identical both days. Some sun with a cloud over it and a lightning bolt coming out the bottom. Some television meteorologists include descriptive words to help describe the "flavor" of the day on the graphic. Common words used: scattered, widespread, isolated. Quick: what do those words mean? Which is the "wettest" sounding to you?? In my opinion, these words are too easy to misunderstand. So, we use PoPs. Here's the 7-day forecast WITH PoPs: 7day(Note: the icons are the same as the graphic above....my screen capture program just snapped this picture while the animated lightning bolts were not visible)So, you are busy and only half-listening (like my wife! heyooooo) and just have time to glance at this graphic. Very quickly, you should be able to determine that Saturday is likely to be the "wetter" of the two weekend days.This is not an exact science. There are situations when one part of the area is much more likely to get precipitation than another area. For example, a storm is just scooting by to our south. It will surely rain in Columbiana County for awhile, but northern Mercer County won't have a drop. What to do?? Of course we will explain the situation verbally but what about graphically? Often we just have to take an average. The PoP is 100% in Columbiana County but 10% in Mercer County. On the graphic we may just put 60%. Again, not an exact science.Some PoP guidelines, pulled straight from the PoP Gospel According to Eric:0%: The day will be dry throughout the viewing area.10%: We can't "completely rule out" a totally random rain/snow shower.20%: Anything that occurs will be very isolated. Often used on hot Summer days when some random thunderstorm might pop up.30%-40%: Used for hit-or-miss activity (think: thunderstorms or snow showers) in the short term (days 1-3) and as a "generic' chance in the long range (days 4-7). Rarely is a PoP higher than 40% used on days 6-7, since the confidence in any forecast is naturally lower that far out.50%: NEVER USED! There enough jokes out there about weather people just flipping a coin! We don't need to give other people a fat pitch down the middle to hit. (I use a dartboard instead of a coln anyway.)60%-80%: Measurable precipitation is likely (but not guaranteed) to occur at some point in the day.90%: Look, it's gonna rain/snow, but we have commitment issues. 100% is sooooo certain. We like wiggle room.100%:rainAnother misconception:A high PoP (say, 70% and up) means precipitation will be heavy and/or the day will be a washout. NOPE! Say a line of thunderstorms seems pretty likely to cross most of the viewing area from 10am-2pm. We go with a PoP of 80%. Most of the day will be dry though! This is the type of forecast that you would only likely see 1-2 days in advance since predicting a 4-hour window when it's likely to rain would be difficult 5 days out.I hope you found this post useful. I always welcome your feedback. Post questions or comments here or on my Facebook/Twitter pages.Eric 

BLOG: Why No Warning? Plus: a Look at Tornado History in Valley and a Look Ahead

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This evening I wanted to take some time to discuss the tornadoes in our viewing area and what made this situation challenging for meteorologists at the National Weather Service and on television.As you probably know by now, the tornado in Mahoning County was not preceded by a Tornado Warning from the National Weather Service. Many have been upset by this and that in understandable. Particularly if your property was damaged. While ideally every tornado is warned for ahead of time, the science is just not there yet. In fact, in the United States, about 70% of all confirmed tornadoes occur in an active tornado-warned area. That means that 3 out of every 10 occur where there is no official warning. This success rate is about DOUBLE what it was 30 years ago, but of course, still not good enough.Many tornadoes that are not warned are ones like we had near Canfield. They drop quickly and then lift quickly...leaving behind little evidence on Doppler Radar that a tornado is occurring. We rely heavily on Doppler Radar to detect tornadoes. It DOES have limitations through.Canfield is roughly 66 miles as the crow flies from the National Weather Service radar, which is located southwest of Cleveland. distancebeamBecause of the curvature of the Earth, the height of the radar beam increases with distance away from the radar site. 563px-Radar-hauteur-en.svgBy the time the beam is over Canfield, it is about 5,000 feet in the air. This can make rotation in the lowest levels of the atmosphere hard to detect. Here is the wind velocity image from right about the time the tornado touched down (2:12pm): canfieldvelocNotice, there is a "spike" in the wind velocity data being detected at exactly the spot the tornado touched down. BUT, no rotation is detected. We would have seen some greenish colors near that location had rotation been detected. Compare that image to the tornado in Mercer County: tvsA NICE "couplet" of green (wind blowing toward the radar) and red/yellow (wind blowing away from the radar). Clear rotation and an easy Tornado Warning for the NWS (in Pittsburgh) to issue.Despite the lack of a rotation "signature" on the Canfield tornado, at 2:12pm, there was an interesting signature on the "regular" radar. A hook shape was evident for only ONE scan: hookThis caught my attention during our online streaming coverage, but with no clear rotation in the velocity data I did not immediately declare that this was likely a tornado and people should seek shelter. In hindsight I probably should have played it up more, but this was a tough call to make on the fly.I thought it may be interesting to take a look at the recent history of tornadoes in Mahoning and Mercer counties. I showed these graphics on the air this evening showing the most recent twisters in the counties: MahoningTorMercerTorA more thorough list of tornadoes, going back to 1950. These tables include the location, the damage caused, the rating on the Fujita scale, among other things.Mahoning: mah1Mercer: mercerInteresting to note how many more tornadoes there have been in Mercer County. I am not sure why this is, other than it being a larger county.There have been ZERO F4/F5 tornadoes in Mahoning County since 1950. The strongest on record was an F3 twister shown here: 1956The longest-lived tornado I could find was this one (F2) from 1963 that was on the ground for 15 miles and paralleled Rt 224: 1963 How about a quick look at the FUTURE weather? After a warm weekend, next week is looking quite cool for July, especially during the middle of the week. Check out the upper-air pattern: 500Looks like it did in the Winter! Deep trough over the Great Lakes. That's actually part of the Polar Vortex! Remember, the Polar Vortex exists year-round (despite the hysteria in the media during the Winter, much of implying this was some sort of new thing). This will result in a big area of below-average temperatures: departSince it is July and not January, that means temperatures will not be "cold" but we will see at least a few days with highs closer to 70 than 80. 90 is certainly out of the question. We have not had a 90 degree reading yet this year. How unusual is that? Not all that unusual. Here's a list of years with ZERO 90 degree days for the entire year. no90sannualHere's the list of Julys with no 90+ days; no90sjulyThanks for reading!Eric 

BLOG: Heavy Storms, Possible Severe Weather

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The holiday weekend is over and so is the tranquil weather! We have a busy couple of days coming up so let's get right to it.As you head out today, you will notice it's more humid than it has been over the last couple of days. Here's this morning's weather map: nowA warm front moved through last night and dewpoints have come up significantly. Check out how high the dewpoints are in parts of the region, especially to our west: dewThat soupy air mass is pushing into the region ahead of a weak cool front. As that cool front pushes east, it will help lift this moist, unstable air mass and some thunderstorms are likely to get going this afternoon. Here is the 2pm simulated radar off of the HRRR model: 2pmThe threat for thunderstorms will be with us through the end of the afternoon/early evening. It is important to note that MOST of these storms will NOT be severe. Sure, they will have plenty of lightning and some tropical downpours. But most will not produce hail 1" or larger or damaging winds. BUT, the potential is there for a COUPLE of them to reach that threshold.The Storm Prediction Center has the entire region in the enhanced risk zone today: DAY1The odds of a damaging wind gust within 25 miles of any location are about 15% today: WINDSame with large hail: HAILThe tornado threat, while not ZERO, is very low. SPC has us in the 2% area. TORUnfortunately this is not the only day we have a severe weather threat this week. Tomorrow could be quite busy as well! Taking a look at the mid levels of the atmosphere (about 500 millibars or 18,000 feet), notice today we have our (fairly weak) disturbance moving through the Midwest and Great Lakes....and a stronger system getting set to exit the northern Rockies: 500todayBy tomorrow, that system will be pushing through the Great Lakes and causing more showers and thunderstorms: 500tueOnce again we are in the SPC enhanced risk zone, and for good reason. Any storms tomorrow afternoon could pack quite a punch. day2More details on tomorrow's weather once we get through today!Thanks for reading.Eric