Should Local TV Stations Be More Consistent With Severe Weather Forecasts?

It’s been a couple of years since I’ve posted here on my blog. Just wanted to put in my 2 cents about the severe weather event that occurred on April 26, 2016 and the OKC media’s role in preparing their viewers in the upcoming days prior to it. This post is more about the media and less about what went wrong with the severe weather event.

For almost a week before April 26, weather forecast models were hinting at a very robust, negatively tilted trough sweeping through the Southwest U.S., then lifting north through the Plains. Even I was impressed on how consistent both the Global Forecast System(GFS) and the European Centre for Medium-Range Weather Forecasts (ECMWF) forecast models were about Tuesday, April 26. Most, if not all, forecast models showed ample moisture(both surface and lower levels), energy (CAPE), and good shear.

Minus a couple of factors inhibiting discrete supercell development, it seemed most of the Central and Southern Plains were going to see a severe weather outbreak. Even short-range, high resolution models were predicting an explosive development of discrete supercells, especially in western/southwestern Oklahoma the morning of the event. However, it didn’t pan out the way most meteorologists thought it was going to.

If you look at the storm reports from the Storm Prediction Center (and these are all preliminary reports, with reports still pending), you can be the judge of whether SPC’s Moderate Risk and PDS Tornado Watch were verified. In my opinion, I think the Moderate outlook verified, but not sure about how the outlook categories were drawn.

Tuesday, April 26, 2016 preliminary severe weather reports via SPC. Updates still pending.

The main thing I really want to talk about is the media’s, local especially, role in preparing and informing the public on upcoming severe weather. Here in the Oklahoma City TV market, it seems each station has their own language, scales, and “warnings” in preparation for a severe weather event, whether the severe risk is small or large.  If you’re like me, you don’t just watch one news station. You’ll watch several stations to get an idea of who is saying what. If it were just news, inconsistencies would be somewhat tolerable, depending on their sources. However, for the weather, I feel it should be different! This has been a major problem for as long as I have been living in Oklahoma (and most likely before), but especially since 2013, after the Moore, OK tornado.

Take a look at the differences each TV station (minus KOKH) in Oklahoma City had leading up to April 26:

KFOR (Channel 4):

Via KFOR

Via KFOR

Via KFOR

KWTV (News 9):

Via KWTV

Via KWTV

Via KWTV

KOCO (Channel 5):

Via KOCO

Via KOCO

Via KOCO

Let’s forget about the accuracy of how each station did. Let’s also look past the critical mistakes (and there are a few for each station) that some of these graphics entail. You can easily see where the problem lies. Each station has its own “rating system” and tornado probabilities, none of which are consistent.  To be fair, KOCO and KOKH (Fox 25) do a great job using SPC’s convective outlooks (Marginal, Slight, Enhanced, Moderate, High risks).

Here’s my solution(s) to this, and maybe you might disagree: each station be much more consistent with each other.  This would likely mean a conference call each morning and/or afternoon and/or evening to discuss what each station should say and use as a graphic.  I believe they should also be somewhat consistent with what the National Weather Service says, too. And I get it, these are competitive stations that will likely not easily agree to things, but shouldn’t the viewer’s safety be more important than ratings?

Also, I’m not so sure a rating system is a good idea. People love numbers. People also love percentages. If you say there’s a 6/10 chance of a tornado in a certain area, many people are going to think there’s a 60% chance of getting hit by a tornado. This is not what you should be telling people. Therefore, I think using numbers in scales is a bad idea, though I don’t really have another solution other than using colors instead of numbers. Maybe something similar to the terror threat scale? But even then, it has its flaws. I’m really not trying to criticize any station, but these things have been a problem for many, many years.

Questions? Concerns? Comments? Let me know what you think.

Arctic Cold Start to December

Wind Chill values across the nation at 10AM CST, December 7, 2013

*Blog written on Sunday, December 8, 2013*

It’s not even winter yet, but for 90-95% of the country, you would think differently if you walked outside. Record and near record breaking low & high temperatures were set across most of the nation this week, including Saturday.  Montana got the coldest temps and wind chills this week, with wind chills in the -50sF. In addition to the low temperatures, ice, sleet, and snow made things extremely difficult for the central and northeast CONUS.  The Dallas/Fort Worth area, southeast Oklahoma, and northwest Arkansas were hardest hit Thursday and Friday. Some areas received more than half an inch of ice and more than 4″ of sleet. This has led to traffic problems, especially in the DFW and Little Rock areas.

So when will things warm up? For North Texas, temperatures should rise above freezing later this afternoon for the first time since Thursday morning. For places like Oklahoma and the rest of the Southern Plains, probably not until Tuesday afternoon. Roads will continue to be slick until then.  The rest of December looks to be warmer for most of the nation, either near normal or slightly above normal. CPC is predicting above normal temperatures the week before Christmas for the western, southwestern and southern US, while the north/northeast temps stay near or slightly below normal:

CPC’s 8-14 day temperature probability between December 17 and 21.

Messy & Cold Setup for Texas (11/24/13)

*Blog written at 12:10 pm CST 11/24/13*

It will be a messy next couple of days for western, northern and even central Texas. Currently snow is falling in the Texas Panhandle, and a mix of rain, freezing rain and sleet in western Texas.  The precipitation will continue moving eastward, ahead of a upper-level low that is currently over the southwest CONUS.

Sunday, 11/17/13 Tornado Outbreak

*Blog Written at 11:30pm CST 11/17/13*

I will be the first one to admit that I was not totally convinced of a tornado outbreak on Sunday, November 17th, 2013 until the morning of. Though I was aware that there was going to be a severe weather outbreak, with possibly multiple tornadoes, I didn’t expect this many tornadoes and multiple strong (EF-3+) tornadoes. Because this event just recently occurred in the time of writing this blog, it may take up to a week or so before all tornadoes are accounted for. However, you can get a glimpse of the filtered tornado reports, along with other severe weather reports, below.

The set-up was quite remarkable for mid-November, especially for the Midwest, Great Lakes, and Ohio Valley. At the upper-levels, a significant synoptic trough was found over the central CONUS at 12z, 11/17.  A powerful 100+ knot jetstreak at 300 hPa was located southwest to northeast from OK to central MO.  This put the Midwest/Great Lakes area on the nose of the jetstreak with heavy difluence aloft as well.  In the mid-levels, 12z soundings showed several shortwave troughs embedded in the synoptic trough in the central CONUS. These shortwaves would eventually round the base of the larger trough and influence the severe weather later in the day.  At 850 hPa, a strong 40-50 knot low level jet (LLJ) was observed and advecting copious amounts of moisture from the Gulf of Mexico into the Tennessee and Ohio Valleys.  And finally, at the surface, dewpoint temperatures reached upper 50s and even lower 60s across the Midwest to start the morning. By 16z a surface low pressure was located in southern WI, with a warm front that extended from the low to extreme northeast IN and a cold front that was located from the low, through central MO and points southwestward.  IN and IL were both completely in the warm sector of the surface low at this time.

The setup above, alone, screams severe weather likely.  However, the previous night I was looking at forecast soundings from GFS and NAM and I wasn’t really impressed by the thermodynamic setup.  Obviously in hindsight, there was enough instability to cause a major tornado outbreak.  While it’s true that you don’t need 2000+ J/kg CAPE for severe weather, it was my belief that much more instability was needed for a major tornado outbreak than what 00z 11/17 NAM & GFS models were outputting. Both models had 750-1000 J/kg for the majority of the severe weather risk area, with pockets of 1000-1500 J/kg.  Again, this is more than enough for tornadoes, but I wasn’t really liking lapse rates and CAPE values being output by both models.  Looking at the 12z 11/17 and additional soundings in the area, it’s obvious that the lapse rates were steep enough. Lesson learned for next time.

So here are all of the severe weather warnings issued on 11/17 from 12z to 0530z (6AM – 11:30PM CST). Image from corymottice.com :

Severe weather warnings from 12z to 0530z  (6AM – 11:30PM 11/17/13)
Red polygons are tornado warnings, yellow polygons are severe thunderstorm warnings.

Cory Mottice’s website also has the official preliminary tornado count and NWS surveyed tornado ratings.

As stated in the first paragraph of this blog, here are the preliminary, filtered tornado and severe thunderstorm REPORTS from the Storm Prediction Center as of 0625z (12:25am 11/18):

Filtered severe storm reports from SPC from 11/17/13 as of 0625z 11/18

First Arctic Cold Front of the 2013-2014 Season

*Blog written at 11:00pm CST 11/8/13*

The first arctic cold front is expected to pass through much of the central and eastern U.S. by early next week.  Most forecast models have a 1045hPa, or strong, surface high sweeping down the Plains, from Canada.  There won’t be much moisture to work with, but  a few locations in the northern Plains, Great Lakes region/Ohio Valley, and Appalachian Mountains could receive a few inches of snow behind the front. This is also where the coldest temperatures will be, with some locations dipping into the single digits for nighttime lows. The cold front will pass through Oklahoma City sometime on Monday(11/11) evening, though details are still sketchy with exact timing. In Oklahoma, temperatures will be in the lower to middle 20s as lows on Wednesday(11/13) morning. 

 

 

*MSLP and 10m winds (shaded), valid Tuesday morning at midnight.*

Invest 93L (Updated 9/11/13)

Invest 93L and 3 possible tracks it could take.
Image Courtesy: UW-CIMMS

(Blog written at 12:30am CDT 9/11/13)

The National Hurricane Center is monitoring a disorganized complex of thunderstorms, invest 93L, in the western Caribbean Sea, circled in yellow above. As of 12:30am CDT 9/11/13, NHC had a 20% chance of development into a tropical cyclone within 48 hours and 70% of development into a tropical cyclone in the next 5 days. Most of the forecast models do develop a tropical cyclone, once this system enters the Bay of Campeche (Gulf of Mexico). However, each model differs on the exact location and intensity of the storm once it does enter the Gulf of Mexico.  The GFS model seems to be the most aggressive model so far, blowing the storm up to at least tropical storm status and making landfall somewhere between Brownsville, Texas and Tampico, Mexico.  Regardless of what this storm does, it will bring lots of rainfall for northern Mexico, the Rio Grande Valley, and south Texas over the next 5-7 days.

Some hazards will include flooding, obviously.  The brunt of the rainfall will be in the north, northeast and east side of this storm, according to the forecast models.  Damaging winds will be another concern, but mostly in and around the center of circulation of the disturbance, unless it does strengthen.  If the storm gets strong enough, storm surge will be a threat to the coast. Finally, waterspouts and tornadoes are always a possibility with tropical systems. Hard to tell, right now, where the most dangerous conditions will be, since landfall is still 4-6 days away.

The above image shows 3 possible tracks that invest 93L could take. Of course, it will be monitored over the next few days. There is still a slight possibility that a cyclone may not develop at all. Heavy rain is still possible for south Texas, even if one doesn’t develop. I will be sure to keep my blog updated if there are any important updates.

A Wet Ending In Late August/Early September for South Texas

*Blog written on August 25, 2013 at 5:00am CDT*

Much of south Texas is dry and in some sort of drought (below image). The month of September is usually the “wettest” month of the year for much of the area, according to climatological data. However, deep south Texas will be seeing the potential for some good rain the last week and a half in August, and even through the beginning of September.

Drought Monitor as of August 20, 2013. The US Drought Monitor is updated weekly, every Tuesday and released every Thursday.

So just how much rain will deep south Texas be receiving over the next couple of weeks? That’s very hard to say. Rain and thunderstorms will occur on a daily basis over the next few days, but it will likely be hit and miss events. Here’s why:

0000z August 25, 2013 700mb analysis. Image courtesy: College of Dupage

An inverted trough is located over the western Gulf of Mexico and is slowly moving westward. This will provide tropical and subtropical moisture to form and move inland from the Gulf. Mid-level flow will be providing ample opportunity for showers and thunderstorms to form, especially during the heating of the day, and will help kick-start sea breezes along the Texas coast. As long as this pattern sticks around, subtropical and tropical moisture will continue to be fed into Texas coast.

Something else that might be contributing to rain and thunderstorms in south Texas will be a tropical wave (AL95) in the Bay of Campeche (shown below).  As of early morning, August 25, this tropical wave is not affecting south Texas much. However, there is a chance that some of its tropical moisture it produces may slide north and affect south Texas. This tropical wave is not forecast to strengthen much over the next 48 hours, but may develop into a weak tropical depression before making landfall around Veracruz, Mexico on Monday.  The less organized this storm is at landfall, the more rainfall south Texas will receive. I know that may sounds contrary to what you’re thinking, but the more organized this storm becomes, storms will be concentrated around the center and less likely to reach the Rio Grande Valley. Since mid-level flow won’t be changing much over the next 3-4 days, I expect showers and thunderstorms to flare up, whether directly or indirectly influenced from this tropical system.  And of course, there’s always the chance it may shift more north or south than what forecast models say.

IR satellite showing  Invest AL95 as of 0945UTC August 25, 2013.

 

As far as how much rain, here’s one model’s thinking of how much rain will be falling between now and 7 am Saturday, August 31.  As you can see, much of south Texas is expected anywhere from half an inch of rain, to just over an inch in some places, and locally heavier amounts possible. Again, this is one forecast model (one possible solution) of many.

00z August 25 ECMWF model showing total rainfall between late PM, Sunday, August 24 through early AM, Saturday, August 31, 2013. Image Courtesy: AccuWeather Pro. 

 

No matter how much rain is received over the next few weeks, south Texas will still likely be in a drought, since much of the area is about half a foot below normal.

Summer Severe Weather in the United States

*Blog written at 1:00pm CDT 6/26/13*

Summer is here and that means hot for most in the United States.  But along with summer heat, severe weather also poses a threat for many, especially those living in the northern Plains and northern Midwest. Obviously, severe storms can occur any day of the year, but I wanted to focus on where and in what form severe storms occur during the summer months.

You may or may not know that criteria for severe storms, as defined by the National Weather Service, are: tornadoes, and/or at least one (1) inch size hail, and/or wind gusts of at least 58 miles per hour.  As stated above, any of these three criteria can occur on any day of the the year.  During the summer months, tornado outbreaks (as defined by my definition of >10 different tornadoes in a 200 mile radius in one day) don’t usually occur that often. There are a couple of reasons why this is.  Temperatures climb into the 90s or even the lower 100s during peak heating hours of the day in most locations in June, July, and August.  While daytime heating is good for thunderstorm initiation, this usually creates a huge dewpoint depression, or the difference between air temperature and dewpoint temperature. Typically, for tornado development, dewpoint depression is often less than 20 degrees, with best opportunity at 10 degrees or less. Of course, this does not mean it is impossible for a tornado to develop with a dewpoint depression of >20 degrees.  The main threats when there is such a gap between temperature & dewpoint are wind and hail.  I will give a brief explanation why in a bit.

Now, I know what you’re thinking, what about the areas that don’t make it into the 90s and/or 100s, especially during the early summer days?  It all has to do with mid-and-upper level patterns. The best areas for tornadoes during the summer months are the central/northern Plains and northern Midwest.  Temperatures are relatively cooler in these areas during the early summer days, along with the favorable jet stream location in this area.  Typically, sometime during June, a pretty strong mid-level ridge builds into the southern/central CONUS. This not only forces the jet stream north, it acts as a “blocking pattern” in the mid-levels, which meteorologists call the “Omega Pattern”. Find more blocking patterns here.  Mid-level troughs/cutoff lows (lower isoheights) are either forced to crest the ridge or retrograde westward.  Often, during the summer, an elevated mixed layer (EML) will be present in the lower troposphere, mainly due to the upper level ridge. In simple terms, a warm layer of air is embedded just a few kilometers above ground level, which prevents surface-based storms from forming.  Tornadoes are often formed from “surface-based storms”. Storms that form above the EML are called “elevated storms” and pose a major hail and wind threat, with a very slight tornado threat.  Elevated storms that form along a boundary layer (cold front, warm front, dryline, outflow boundary, etc.) either clump together and/or form a line of storms.  This is how a Mesoscale Convective System (MCS) forms.  There are a couple of forms of MCS’s (product of severe storms) that can be recognized on Doppler Radar: bow echoes & squall lines. Bow echoes are usually formed from squall lines.

The reason why wind and hail are the main threats with any MCS is because downbursts are associated with MCS’s.  Because cold air is more dense than warm air, rain cooled air a few kilometers above the much warmer ground will crash down, at fast speeds, and spread out once it hits the surface.  This creates damaging straight-line winds, sometimes exceeding 100 mph.  Updrafts in these storms are very strong, capable of producing very large hail, as well. The stronger the updraft, the stronger the downdraft (wind & hail). Because mesoscale convective systems are usually clustered and elevated  thunderstorms, tornadoes are less likely to be produced, but not impossible to form.  In fact, tornadoes are more favorable to form at either end of bow echoes, in a area called the bookend vortex.  Rotating supercells may also be embedded in the MCS.  These systems usually last anywhere from 3-6 hours, on average and can travel hundreds of miles at times.

Derechos are also a form of MCS, but certain criteria are also needed to define a derecho:
1.) Wind damage swath has to extend more than 240 miles (400 km).
2.) Wind gusts of 58 mph (93 km/h) must be along most of its length.

Find more about derechos here.

Severe Weather 6/11/13 & 6/12/13

*Blog written at 2:15pm CDT, 6/11/13*

An enhanced severe risk of severe weather is expected to take place today, 6/11/13, and tomorrow 6/12/13.  The primary threat will be damaging straight-line winds, each day, but very large hail, flash flooding, and a few tornadoes are also possible.  A shortwave trough will be rounding the crest of a developing mid-level ridge. By this evening, the trough axis will be located from southeastern MT to northeastern CO. A surface lee low will be advancing eastward tonight, across the central High Plains.  Rich low level moisture, daytime heating and shortwave trough influence will destabilize the boundary layer, creating severe weather from south-central & southeast MT, northeast WY, much of SD and northern NE. The severe threat will continue into IA, southern MN, southern WI and northern IL into the evening hours.  Again, the main threat will be straight-line winds, but very large hail and even tornadoes will be likely with any stronger, discreet supercells that form.  The tornado threat will likely diminish into the evening hours, once an MCS (Mesoscale Convective System)/linear line/bow echo of storms develop. SPC has issued out a “MODERATE” risk of severe storms for both days. SPC’s Day 1 (6/11/13) severe wind outlook:

SPC’s severe wind probabilities for today. There will also be a significant hail threat for much of this same areas.

Thunderstorms will persist into the morning hours tomorrow, 6/12, for much of the High Plains and Midwest regions.  Surface low will deepen before reaching the Ohio Valley, tomorrow afternoon.  Few supercells will be likely by afternoon, but storms will quickly cluster together and from an MCS that will produce damaging straight-line winds and large hail. This MCS will likely trek eastward through northern/central IL, southern MI, northern/central IN, northern/central OH and much of the northeast states by Thursday morning. There is a strong possibility that a derecho, or a very large and destructive bow echo, may form.  In addition to the wind/hail threat, heavy rainfall is expected. Flash flooding will also be a huge problem!  SPC’s Day 2 (6/12/13) Severe Probability Outlook:

SPC’s Day 2 severe probability outlook. Significant wind and hail threat will be likely tomorrow, 6/12/13.

The severe threat will continue into Thursday afternoon and evening for a good portion of the east coast.

Summer Is Approaching

Blog written at 5:00am CDT, 6/10/13

A mid-level ridge will build in this week, 6/10 – 6/14, for much of the central CONUS. This will keep things mostly dry and very warm.  Some places, such as Wichita, KS and Oklahoma City, OK will hit >=90 degrees for the first time this year on Monday, June 10. This is a summer-like pattern setting in for much of the United States.

 

Mid-level ridge will strengthen over the middle CONUS this week. Temperatures will spike up for most areas in the Great Plains. upper 90s and 100s will be likely for  areas Texas, Oklahoma, Colorado, Nebraska and Kansas.