Showing posts with label flooding. Show all posts
Showing posts with label flooding. Show all posts

Wednesday, December 14, 2022

Perspective on the 35th anniversary of the West Memphis tornado

[ This blog post was originally posted on the 25th anniversary of the West Memphis tornado of 1987. I am resurfacing it ten years later, on the 35th anniversary, for multiple reasons. 1) It was a significant and deadly event, which could have MUCH worse had the tornado hit the dog track packed with spectators. 2) And as the first in a triplicate of major weather events in a roughly two-week span, it also sparked the flame in me that continues to burn to this day, resulting in a career in aviation weather that has been fruitful and rewarding, as well as a side business that provides another outlet to exercise my passions for weather, making a difference by keeping people safe and informed, and giving back by mentoring the next generation of successful meteorologists. Thanks for reading! /EP ]

ORIGINALLY POSTED DECEMBER 14, 2012:

A quarter-century ago, I had been living in the Memphis area for just over a year and was in middle school when an event occurred that I now believe was the first spark that started the fire, igniting a passion that lives in me to this day and likely determined my future career path.

The West Memphis Tornado of 1987

On Monday, December 14, 1987, at 9:40pm, a major twister touched down just southwest of West Memphis, AR and moved rapidly northeast at 60 mph, tearing a path through the city across the Mississippi River from it's namesake, then blew across the Mighty Mississippi (thus disproving the myth that the river and bluffs protect Memphis and Shelby County) and into Meeman-Shelby Forest State Park in northwest Shelby County before lifting just west of Millington, TN.

Track of the F-3 tornado that passed through West Memphis, AR and crossed the river into Shelby County, TN

By the time it was done, F-3 damage was recorded in both Arkansas and Tennessee along a 25-mile path, six people were dead, and 121 others were injured.  Damage estimates were approximately $35 million [1987 dollars], including 235 homes, 35 businesses (many along Broadway street in downtown), and a school in West Memphis and 88 homes in the Northaven development west of Millington that were destroyed or heavily damaged.  In all, 1,500 people, or roughly 5% of the population of West Memphis, were left homeless.

According to Associated Press archives, Arkansas Governor Bill Clinton sent in the National Guard and additional state troopers to put a halt to looting in the central business district following the tornado.

The tornado also struck several high voltage power lines, including two 500,000 volt lines and three 161,000 volt lines, leaving much of Crittenden County, AR without electric power. Those killed included a woman in her mobile home, an elderly man in a boarding house, a teenager in a grocery store parking lot, a one-year-old child in an apartment building, a person in a vehicle that was thrown on I-40, and a person in a truck stop parking lot.

As bad as it was, the destruction could have been much worse.  At the time of the tornado, 7000 spectators were at Southland Greyhound Park dog-racing track in West Memphis, which the twister missed by just one-quarter mile. Video below is courtesy KATV meteorologist Todd Yakoubian (@KATV_Weather on Twitter).


Meteorological setup

From a meteorological perspective, the tornado appeared to form just behind a warm front that lifted through the area.  From observations taken at Memphis International Airport (the closest recording station to the tornado), it was 50 degrees at 7pm with wind from the east at 6 mph and dense fog being reported. An hour later, the temperature had climbed to 66 degrees (after dark) and wind shifted to the southeast at 21 mph with fog lifting. Between 9:00-10:15pm, the temperature was 70 degrees and wind gusted from the southwest at up to 40 mph as pressure bottomed out at 29.38".

Surface map valid at 9pm with the surface low moving by just west of West Memphis.  The map indicates that it was 70 at Memphis Int'l and 40 in Jonesboro, AR with heavy snow falling in the Ozarks.

By 7am the next morning, the temperature had fallen back to 32 degrees following a night of westerly wind that gusted between 35-48 mph.  Weather maps show a potent upper-level disturbance moving by just west of the area and a rapidly-strengthening surface low moving through AR that evening.

Daily weather map for the morning of December 14, 1987. Low pressure over south TX lifted rapidly north and strengthened, reaching Chicago the next morning. The track of  the low through AR put the Mid-South in prime position for wintertime severe weather.

Upper level weather maps from December 14, 1987 at 6pm. Upper left: a strong jet stream over the Mid-South. Upper-right: an upper-level disturbance moving by to the west. Lower-left: low pressure at 5,000' over southern MO. Lower-right: surface low pressure over AR moving rapidly north, placing the Mid-South in the storm's "warm sector."

A triple case of bad luck

Unfortunately, the tornado was just the first event in a series of cases of bad luck dealt by Mother Nature. The town had not recovered from the tornado when parts of it flooded from 12" of rain eleven days later, on Christmas Eve night, leaving 1000 homes flooded and another person dead. Then, 7-10" of snow fell on January 6, another 11 days after the flooding rains. As snow melted, it added to the already existing misery caused by the flood and the destruction caused by the tornado.  Oddly enough,  West Memphis became the first U.S. city to be declared a federal disaster area twice in a two-week period due to this string of events.

A personal note

Many times, when a meteorologist is asked what triggered their interest in weather, it is a singular event that had an impact on their life. For many years, I was unsure of what that event in my life was.  However, I knew that my passion began in the middle school years, shortly after I relocated with my family to the Memphis area. There is no doubt now though, as I now vividly recall the destruction of the city upon driving through it with my parents within a few days of the tornado, that the West Memphis tornado of 1987 was THAT event in my life. I find it hard to believe that it was 25 years ago!  Perhaps that is also why I am so passionate about making sure people are informed and taking precautions when severe weather strikes, which has resulted in the services offered by MemphisWeather.net and our mobile app-based weather alert system - StormWatch+.

Do you have more than a passing interest in weather, even if you're not in the profession?  What event triggered your  interest?  If you've lived in the Mid-South for a quarter century, what do you recall about this event? I'd love to see your comments below!

Erik Proseus
MWN Meteorologist

--- 
Follow MWN on Facebook and Twitter for routine updates and the latest info! 
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app 
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder



Friday, February 22, 2019

Overnight storms, then severe storms -- but the end is in sight!

The drumbeat of raindrops falling is incessant... and we're not quite done. In fact, the next 24 hours or so pose more risk than we've seen in a few months, both in terms of the flash flooding potential and the severe weather risk. Let's start with the water, then move onto the storms.

Rest of today and tonight

Continuous rain today, though perhaps not as heavy as what we've seen recently, is keeping things saturated. Metro areas in west TN and east AR have seen 1/3 - 1/2" of rain since sunrise this morning (as of 2pm) while northwest MS is likely pushing an inch. The heaviest rain since yesterday has been southeast of the metro where Flash Flood Warnings are in effect. Today's rain is on top of 5-7" the metro has seen in the past 2 weeks, as shown below.

14-day precipitation totals (since Feb. 8) show 5-7" of rain has fallen through early this morning. (NOAA via WeatherBell)

Steady rain is likely to continue this afternoon and perhaps into the evening, though high-res models disagree a bit on a potential break in the rain for the early evening hours. However, once we get into the nighttime, after about 10pm, a warm front to our south will lift north and cross the metro overnight, pushed by an increasingly strong southerly low-level jet stream a couple thousand feet up. That will result in periods of thunderstorms overnight, perhaps lasting much of the night.

The high-res HRRR model future radar product through 7am Saturday shows the overnight storms lifting north through the metro ahead of a warm front. (WeatherModels.com)

Rainfall will be heavy enough in these storms to be classified as "frog-stranglers" and "gully-washers," dropping up to 2-3" overnight, perhaps higher in spots. Flash flooding becomes a much more concerning trend as the night goes on, so if you will be out overnight, be extremely cautious! Creeks and streams could overflow, rivers are already high, and low-lying or poor drainage areas in the urban jungle could see accumulating water. If you live near a creek or stream or other area that floods in very heavy rain, be aware that could happen overnight. The NWS Weather Prediction Center has the metro straddling the line between a moderate and high risk of rainfall that exceeds levels required for flooding, or about a 50% chance within 25 miles of you. North MS has already seen some water rescues in the past 24 hours - flooding is a threat to be taken seriously, particularly south of the state line!

The Memphis metro is in a Moderate (level 3/4) threat area for flooding through tonight, while north MS is in a High risk (level 4/4). This means there is about a 50/50 chance of having  rainfall exceed flash flood criteria within 25 miles of you. (NOAA/WPC) 

As far as storm threats, we're not necessarily expecting them to be severe. The Storm Prediction Center has our area on the edge of a Marginal Risk (level 1/5) for severe weather, with the possibility that a few storms could have some hail. Damaging wind and tornadoes are not currently expected overnight, but that doesn't mean the storms won't make a racket! If you had issues with storm noise Tuesday night, expect it again tonight (and it may last longer). Also know that due to the frequent lightning, power outages will also be possible.

SPC has the metro outlooked in a Marginal Risk (level 1/5) for severe storms overnight. The main threat is a few hail storms, but even that threat is very low. Storms will produce plenty of lightning and thunder though! (NOAA/SPC)

Saturday

Once the warm front moves to our north, we should catch a bit of a break for a while Saturday morning. By about sunrise, the storms will be to our north and a humid, very warm, and increasingly unstable airmass will overtake the area. Temperatures in the morning will rise to near 70° with gusty south wind and hit and miss showers or a thunderstorm. The stage will be set for the potential for severe weather in the afternoon as a potent cold front cuts through an airmass characterized by strong, turning winds aloft (bulk shear over 50 kts and SRH near 200 for you weather nerds), sufficient instability (CAPE of 1000-1500), and plenty of available moisture at all levels (PWAT near 1.6").

Storms will likely form ahead of and along the front by late morning in AR and move our way by early afternoon. We are expecting a line of storms, with perhaps additional storms ahead of the line, during the afternoon hours Saturday, or roughly between 1-5pm. These storms will tap into the springtime atmosphere and have the potential to produce damaging wind gusts and a low threat for a couple tornadoes embedded within the line.

The HRRR model forecast radar simulation from noon to 6pm Saturday shows a broken line of storms moving through the metro, intensifying as they near the Mississippi River about 4pm. A few storms are also possible ahead of the line. (WeatherModels.com)

A second possible solution for Saturday, from the high-res NAM model looping from 10am-8pm Saturday, shows an earlier arrival of the storms, and perhaps a couple of lines between 1pm-4pm. It also depicts more organization of the storms as they move towards the metro. (WeatherModels.com)

Severe weather threats

While the threat of damaging wind will be much higher (right now pegged at about 30% within 25 miles of any point), a Tornado Watch is likely during the afternoon as tornado probabilities are currently forecast at about 10% within 25 miles of you. Consider now what your plans are for Saturday afternoon and be prepared to take shelter wherever you are, if necessary. In addition, with the excessively wet ground, storms that produce sub-severe wind gusts (40-50 mph) may be sufficient to uproot trees and cause power outages. A Wind Advisory has also been issued for non-convective wind gusts to 30-40 mph Saturday would could pose an additional threat to trees with shallow roots in saturated soil.


After the storms

By 6pm Saturday evening, the storms will likely be gone and evening plans should continue with little concern. Moving into Sunday and early next week, I am pleased to report that it will be DRY with plentiful sunshine and seasonal temperatures. A few mid to late week showers are possible, but there is currently no threat of heavy rain that would cause additional flooding concerns as high temperatures remain in the mid 50s to near 60.

Stay tuned to our social media channels for the latest updates and be sure you have the MWN app downloaded with StormWatch+ Alerts activated for your locations of interest. Links are presented below.

Erik Proseus
MWN Meteorologist

----
Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Sunday, February 17, 2019

[MWN VIDEO BLOG] Where are those ark plans? Flooding rain possible over the next week

I know we're tired of the rain, but another very wet week is ahead. The potential for flooding and flash flooding exists with heavy rainfall Tuesday into Wednesday and again Saturday into Sunday (next weekend), though rain chances occur nearly every day this week, except Monday. Watch the video forecast discussion below for all of the details or check out the graphics below for a high-level overview.



Unable to view the video? Try clicking here: https://youtu.be/jjTosUgi9-Y

Rainfall over the past week, laying the groundwork for possible flooding this week by saturating the ground across the region. (NOAA/NCEP via Pivotal Wx)

The GFS model shows repeated surges of atmospheric moisture (shown as precipitable water) over the southeastern U.S. over the coming week. (PivotalWx)

Total precipitation forecast through next Sunday from NOAA's Weather Prediction Center. 4-7" of rainfall is projected in the Memphis area with 10"+ in the TN Valley. (NOAA/WPC via PivotalWx)


Stay with us all week for the latest on the heavy rain and potential for flooding, as well as forecast updates as we tweak the timing and amounts of rainfall with each system as it approaches. Links to where to get all this information can be found below, and certainly be sure to download the MemphisWeather.net app for all of it in one neat little package, including StormWatch+ Alerts for flood and flash flood alerts for your location.  Stay dry (as best you can!) and stay safe!

Erik Proseus
MWN Meteorologist

----
Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Tuesday, March 27, 2018

Here Comes the Rain! Here it comes again…

As allergy season has moved into full effect across the Mid-South, many have been looking to Mother Nature for some relief from the pollen-filled air. Well, the relief arrives late Tuesday night with lots of rain to come, perhaps too much for our ground to handle right now. Let’s break down the coming wet weather for the Memphis area.


The Timeline

So when does the rain begin? The HRRR model shows the rain arriving in the metro shortly after midnight tonight, and hanging on throughout much of your coming Tuesday. Some periods of rain could be heavy at times, especially overnight and into early Wednesday morning. A few thunderstorms will also be possible in this batch of rain. While there may be a brief break in the rain intensity Wednesday, there is a high likelihood of more rain and a few thunderstorms overnight Wednesday into Thursday.

The HRRR model shows rain arriving in Memphis after midnight on Tuesday night, and sticking around for much of Wednesday. (WxBell)
The key takeaway – be prepared for a wet 36 to 48 hours. Flood Watches have been issued through Thursday morning over the entire metro area ahead of this slow-moving system. The rain should finally abate once the cold front makes its final push through Thursday night.

The Threats

Perhaps the biggest threat with this wet pattern for the next two days is the amount of rainfall coming. The Memphis area will likely be measuring the rain in inches over the next 48 hours, with 2 to 4 inches of rain not out of the question. The Weather Prediction Center (WPC) puts the metro in a slight (10-20%) chance of excessive rainfall for Wednesday morning through Thursday morning.

The Weather Prediction Center (WPC) shows a 10-20% chance of excessive rainfall for all of the Mid-South region Wednesday into early Thursday.
There will also be a low-end severe threat to contend with on Wednesday. The Storm Prediction Center (SPC) puts Memphis and the surrounding area in a marginal (1/5) risk for severe thunderstorms, which could include heavy downpours, lightning, strong wind, and perhaps small hail. We do not anticipate a strong tornado threat with this system.

The Storm Prediction Center (SPC) puts Memphis and the surrounding area in a marginal (1/5) risk for severe weather on Wednesday. 

The Break in the Action

After the cold front pushes the rain out of the picture on Thursday night, expect much clearer conditions to begin your holiday weekend. Good Friday looks good for the weather too, with mostly sunny skies and high temperatures near normal in the mid 60s. Saturday looks quite similar as well, with highs in the upper 60s. Lows both nights drop to the mid 40s. The next chance of rain is more scattered, but could but a slight damper on those Easter Egg Hunt plans on Sunday.



Already looking ahead to your Easter Sunday plans? Stay tuned to MemphisWeather.Net on Facebook and Twitter for all the latest on the forecast. You can also check our human-verified forecasts online and on your phone with the MWN app. Team MWN will keep you covered throughout the rest of your week and over the holiday with all the weather for the Mid-South region.

Meteorologist Alex Herbst
MWN Social Media Intern

----
Follow MWN on Facebook, Twitter, and Google+
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Monday, February 26, 2018

Recap of Saturday's severe weather, and more rain??

Given the first Enhanced Risk outlook for Memphis since May 27 (you recall the Memorial Day weekend Tom Lee Storm right?), we fared pretty well. Some of our neighbors not far to the north were not so lucky.

Sequence of events

A Tornado Watch was issued at 3:20pm - our first since August 31, 2017 - as a line of storms moved across Arkansas towards the metro. The most potent airmass would end up being just north of our area where Tornado Warnings were issued from northeast AR across northwest TN. Locally, Severe Thunderstorm Warnings were issued as far south as the I-40 corridor with straight-line wind generally peaking in the 40-50 mph range as the line moved through between 7-8pm, resulting in some scattered power outages but no major damage. By 8:30pm, the majority of the metro was receiving just rain, as the line continued pushing east.

Unfortunately, severe storms dropped at least a couple of tornadoes in northeast AR, the Missouri Bootheel, and northwest TN, including an EF-1 that affected Keiser and Osceola, AR and an EF-2 that struck Malden, MO.


Judging the forecast

Below you can see the severe weather outlook issued at 8am Saturday morning by the Storm Prediction Center, overlaid by the preliminary severe weather reports for the day. Overall, this was an excellent forecast with nearly all of the reports within the Slight (yellow) or Enhanced (orange) Risk areas. You can make out a southwest-to-northeast "path" of the damaging storms across AR to areas just north of the I-40 corridor into central KY.

Our Friday morning forecast indicated the timing of the storms would be between 8pm-1am Saturday night. That was adjusted Saturday morning to between 6-10pm, indicating the primary threat would be damaging wind and flooding, followed by a low risk of tornadoes. Overall, I feel that worked out quite well.

Map showing the Saturday 8am severe weather outlook (color fill) overlaid by the severe weather reports received by Monday evening. (NOAA/SPC)


Looking ahead - more flooding?

While severe weather drew the most attention Saturday, precipitation that totaled 4-5" in the metro and nearly a foot in portions of central AR resulted in high rivers and tributaries and some instances of urban and flash flooding. River flood warnings continue across the region with the Mississippi River itself forecast to cross flood stage by this weekend and remain there for a couple of weeks, cresting about 2.5' above flood stage at Memphis.

Analysis of precipitation that occurred over the past week, ending Monday morning, February 26. Roughly 4-5" of rain fell in the metro in the past week. (NWS / WxBell)
The next system arrives Tuesday night and continues through Thursday morning and promises to be another soaker. There appear to be two periods of potentially heavy rainfall - one Tuesday overnight and another Wednesday evening into the overnight hours. During the day Wednesday, rain chances remain high but amounts should be more manageable. By mid-day Thursday, I'm expecting another 2-4" of rain, locally higher, to have fallen across the area, which should push us over the all-time February rainfall record of 11.14". We're currently about 1.5" shy of that record. Flood Watches are again posted for this time period and rivers will only continue to climb as water simply can't soak in anymore and will run off into drainage areas and then local creeks and streams that feed the rivers.


Once the system departs Thursday, sunny skies are on tap once again heading into the weekend. Could this be the first Saturday in nearly 2 months to be dry and sunny??


Severe Weather Awareness Week

This week is also Tennessee Severe Weather Awareness Week (SWAW), so be sure to check out our SWAW webpage with new weather topics being added daily, as well as our social media feeds where we are giving away free MWN apps and NOAA weather radios this week! In fact, find our pinned post on Facebook and enter to win one of those Midland radios on Tuesday night! We're also running a sale on StormWatch+ in the MWN mobile app - only $5.99! That's a ONE-TIME fee for peace of mind in the form of personalized notifications when hazardous weather threatens. Learn more by clicking here.

Erik Proseus
MWN Meteorologist

----
Follow MWN on Facebook, Twitter, and Google+
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Severe Weather Awareness 2018: Flooding and Flash Floods

Floods and flash floods occur every year in the Mid South. River flooding occurs seasonally when winter or spring rains or torrential rains associated with tropical storms fill river basins with too much water too quickly. Flash floods occur suddenly, usually occurring within hours of excessive localized rainfall. These flash floods can become raging torrents which rip through river beds, urban streets, or valleys sweeping everything before them.

When a Flash Flood Warning is issued for your area, or the moment you first realize that a flash flood is imminent, act quickly to save yourself. You may only have seconds.

A Flood Watch means it is possible that heavy rains will cause flooding in the specified area. Stay alert to the weather, and think about what you would do if water begins to rise or if you receive a warning. Watch for development.

Sometimes, an Urban and Small Stream Flood Advisory (or Flood Advisory) is issued for urban areas when excessive rain from thunderstorms begins flooding low-lying areas, small streams, and areas prone to excessive runoff on roadways.


Be especially cautious when driving heavy rain and avoid areas where water is known to pool or flood during heavy rain. It only takes two feet of moving water to sweep your vehicle away, including pickups and SUVs and six inches of moving water to sweep a person off their feet.  Nearly half of all flood fatalities involve vehicles.


Flash Flood Safety rules

  • Get out of areas subject to flooding. This included dips, low spots, valleys, stream banks, and flood plains.
  • Avoid already flooded and high velocity flow areas. Do not attempt to cross a flowing stream on foot where water is above your ankles.
  • If driving, know the depth of water in a dip before crossing. The road bed may not be intact under the water. Don't drive into a pool of water or where water is flowing. Water up to the bumper will likely stall a car.
  • If the vehicle stalls, abandon it immediately and seek higher ground. Rapidly rising water may engulf the vehicle and its occupants and sweep them away.
  • Be especially cautious at night when it is harder to recognize flood dangers. Heavy rain events frequently occur at night!
  • Do not camp or park your vehicle along streams or drainage areas particularly during threatening conditions.
  • Turn around, Don't Drown!

MemphisWeather.net has the information you need during potential and ongoing floods and flash floods via the MWN Flood Center, which includes current radar and estimated precipitation totals, precipitation forecasts (amounts and timing), and river levels and forecasts. In addition, StormWatch+, available via the MemphisWeather.net mobile apps for Android and iPhone, will alert you if you are in, or drive into, an area that is under a Flash Flood Warning.

----
Follow MWN on Facebook, Twitter, and Google+
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Friday, February 23, 2018

Severe storms may put a bow on this week's rainy pattern

The end of this week's rainy spell is in sight, but we have to get through the potential for a couple more rounds of showers and thunderstorms, as well as one distinct threat of severe weather. The past week (in fact, this month) has seemed to be one rain event leading into the next. Precipitation for the past 7 days looks like this:

Precipitation analysis since last Friday morning (2/16) shows about 4" of rain in the metro and much heavier amounts across central AR. (WxBell) 
So far this month, Memphis International Airport is nearing 9" of rain, which is just over 2" short of the all-time February record of 11.14". We'll definitely make a run at that record.

For today, a nagging frontal system remains generally right over the metro. We'll see continued chances of pop-up showers during the day, though it looks like the next potential "round" of showers and a few thunderstorms could be this evening. Highs today are tricky, depending on cloud cover (a few peeks of sun will be seen) and pop-up showers, but should end up nearing 70° for most areas. The rain chance this evening ends overnight as the region gets firmly entrenched in the "warm sector" of tomorrow's low pressure system that will eventually bring an end to the unsettled pattern we've dealt with this week. Warm sector means southerly wind, muggy air, and warm temperatures - so look for lows tonight to remain in the 60s.

Animation showing simulated radar from noon Friday through sunrise Sunday morning. A few rounds of showers and storms are possible with the "main event" on Saturday evening, likely before midnight. (PivotalWx)
Saturday will feature a chance of showers or a thunderstorm, mainly in the afternoon, but also some brief breaks in the clouds and gusty south wind that help push temperatures into the mid 70s. It'll be a good idea to use that time to secure any loose objects and clean out any leaves or debris that are blocking gutters or drainage areas. 


By evening, as the low pressure center moves by to our north, we'll see a round of strong to severe storms push through the metro ahead of a cold front. Timing of the strongest storms appears to be between about 8pm-1am, with the main threat lasting no more than an hour or so at any one location. Due to the strong wind fields at all levels of the atmosphere and very warm and muggy air preceding it, storms will be capable of damaging wind gusts, perhaps some hail, and a couple of tornadoes. The metro is contained within an Enhanced Risk (level 3/5) of severe weather. Yes, we are on the leading edge of spring severe weather season!


In addition to the severe weather risk, Saturday evening's system will likely produce an inch or more of rain in a short time period, enhancing the ongoing flash flood risk. Flood Watches remain in effect for the region and River Flood Warnings are in effect for some of the Mississippi River tributaries, as well as the main river itself. Always be cautious, especially after dark, when encountering water on roadways. Don't drive across water-covered roads! You don't necessarily know whether the road bed is intact under the water. In addition, due to saturated soil, it won't take as much wind as usual from thunderstorms to bring down trees (perhaps into power lines). I expect we could see some tree damage across the area Sunday morning, even perhaps from sub-severe level wind (say 40-50 mph).

Prepare now

Be prepared for the potential for severe weather after dark Saturday night. It's been quite a while since we have had a substantial threat from severe storms, so take the opportunity to review the safety tips above. We also highly recommend you download the MemphisWeather.net mobile app and activate StormWatch+ within the app for severe weather alerts delivered to you for the locations you are interested in. We'll bring you updated information on our social media feeds throughout the next couple of days, so you can always find us on Facebook or Twitter if you have questions or need the latest info! Links to our feeds are below.

Erik Proseus
MWN Meteorologist

----
Follow MWN on Facebook, Twitter, Instagram and Google+
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Tuesday, February 20, 2018

If it quacks like a duck... (heavy rain expected)

Seems spring has sprung the past couple of days as we've reach temperatures in the mid to upper 70s both Monday and Tuesday. Monday's high tied a record set just last year at 77°. Today's record of 80° (also set last year) may be safe, but not my much. [Side note: the 80° reading last year on this date was the first time we had reached 80° in February in 32 years. We almost did it again today!]

A cold front approaches

The warm, moist air that brings 70s to the region will be the same water-loaded air that is responsible for periods of heavy rain in the coming 4-5 days. It all starts with a cold front that is literally separating winter from spring in the U.S. While the western U.S. shivers, the eastern U.S. is setting dozens of warm weather records. Near the boundary, rain, thunderstorms, and ice are falling as the front slides slowly southeast. (OKC dropped from 68° to 32° and freezing precipitation in just 3 hours!)

Early afternoon temperatures across the CONUS show clearly where the cold front is located. (WxBell)


Wet Wednesday

By Wednesday early morning, that front will move through the metro and the wet pattern commences. Tomorrow will be very similar to last Friday when a high temperature in the mid 60s occurred around morning rush hour and the mercury fell from there in rainfall. We will see temperatures above 60° around dawn, then fall through the 50s into the upper 40s by Wednesday evening with rainfall much of the day.

Though severe weather will not occur, we will likely hear some thunder around the time the front passes early in the day. The heaviest rain will likely occur Wednesday night as the "river of atmospheric moisture" above us is tapped by a passing upper level disturbance, effectively opening the spigot just a little bit further. Rainfall totals through Thursday morning will likely be in the 2-3" range or so for the metro.

NOAA's Weather Prediction Center forecasts approximately 2.5" of rain by Thursday morning. (WPC/WxBell)

A Moderate Risk (category 3 of 4) of excessive rainfall - enough to cause flooding - is forecast with our first round of precipitation Wednesday in to Wednesday night. Flash Flood Warnings are very possible as the event unfolds. (NOAA/WPC)


Thursday-Friday - a small reprieve?

Continued scattered showers are expected Thursday and Thursday night as the front lingers just to our south before pulling back to the north overnight as a warm front. Models have some disagreement on the rain chances Friday, with one camp showing rainfall remaining mainly to our northwest, while the European model is a little more aggressive with scattered storms on Friday. We'll call it TBD and tell you to be prepared for scattered precipitation! Temperatures will still warm up nicely into the lower 70s.

Saturday-Saturday Night - Wet Again

By Saturday and Saturday night though, we'll be moving into round 2 of heavy precipitation. As low pressure moves by to our north and that warm, moist airmass has re-established itself over the Mid-South, showers and thunderstorms will break out. A few storms have the capability of becoming strong with some hail or strong wind gusts possible, mainly during the afternoon and evening hours. With heavy rain also expected though, it's possible that the air may not be unstable enough to generate severe storms. Stay tuned.

The severe weather outlook for Saturday is equivalent to a "Slight Risk" of severe storms, or category 2 of 5 risk. This could change as we draw closer in time though. Follow MWN for the latest. (SPC)
Either way, the Mid-South could easily pick up another couple of inches of rain before it moves out with a frontal passage late Saturday night, yielding a 5-day total of 3-6", or an amount only a duck could be happy about...


Flood Watches are in effect for the entire area (including Memphis and Shelby County) through early Sunday morning . If you live in, or travel through, areas subject to flooding during heavy rain events, that will likely have again this week. As as reminder: "turn around, don't drown." The only way to ensure your safety is to stay out of the water.

Sunday brings a return of dry weather that should last through early next week. Hopefully, some good drying will take place with mild conditions. By then, the all-time February rainfall record (11.14") could be broken however.

River flooding

We'll also be watching the river levels in the area. With the expansive reach and overall amount of water that will fall over the coming week, rivers will be high and could also flood some areas. The spring flood season is starting, including watching the Mississippi River rise as we head into early March. It will also likely eclipse the low end of flood stage and could have ramifications for low-lying areas, including along its tributaries (the Wolf, Loosahatchie, and Nonconnah rivers).

Stay with MWN for the latest on the heavy rain threat(s) via our social media feeds and mobile app with the human-powered MWN Forecast (links below). We'll keep you updated throughout!

Erik Proseus
MWN Meteorologist

----
Follow MWN on Facebook, Twitter, and Google+
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder