(4/19) SIGNIFICANT SEVERE WEATHER EXPECTED FRIDAY 4/19
Updated: May 12, 2019
Potentially dangerous situation tomorrow for severe weather, as confidence continues to grow for significant severe weather Friday afternoon and evening. A vigorous spring severe weather system will bring the threat of severe weather to North Carolina Friday and Friday night. A warm and humid airmass and an approaching disturbance will combine to produce widespread storms, and many of these storms could be Severe. Primary threat are damaging winds 60-80MPH, hail, a few tornadoes, and Flash Flooding Now is the time to finalize emergency plans and ensure that you have a safe place to go if/when Severe Weather threatens. Note a long discussion, but will answer everything you need to know.
1) Widespread Severe Weather is possible tomorrow across NC, many to numerous storms will be Severe. Damaging Straight Line Winds are a good bet for everyone from i77 East, in fact, the Storm Prediction Center has placed a good portion of the state in a 30% chance range of seeing damaging winds to 60-70MPH within a 30 mile range. Damage from severe thunderstorm winds account for half of all severe reports in the lower 48 states and is more common than damage from tornadoes. Wind speeds can reach up to 100 mph and can produce a damage path extending for hundreds of miles.
2) There remains a risk for Tornadoes especially in areas that see more instability, read below for more information regarding TornadoesWe have saturated ground and rivers,
3) Flash Flooding is certainly possible where thunderstorms are training
4) People must have a way of hearing warnings, and that way should never, ever be a siren. Their purpose is only to reach a limited number of people outdoors. Every North Carolina home and business must have a NOAA Weather radio, properly programmed and with a fresh battery backup. Be sure WEA (Wireless Emergency Alerts) are enabled on your phone (check notification settings)... even with no good weather app installed you will receive a tornado warning with a loud audible alert.
WHAT: A warm and humid airmass and an approaching disturbance will combine to produce widespread storms, and many of these storms could be severe. The Storm Prediction Center has defined an "enhanced risk" (level 3/5) from the Triad and points east to the coast, while the rest of state (west) is under a "slight risk" (level 2/5). New model data continues to shows higher instability values (CAPE) than recent runs, supporting the severe potential. The best combination of instability and shear will be over Central and Eastern North Carolina, over the "enhanced risk" by SPC where I believe some sunshine will be present. But strong to severe storms are possible statewide Friday and Friday night... storms could produce large hail, strong gusty winds, Flash Flooding, and a few tornadoes. Everyone needs to be weather aware Friday and Friday night, and have a way of receiving warnings in case they are needed. There still remains some significant uncertainty is regarding CAPE (convective available potential energy) this important for the development of severe weather. However, another important "ingredient" is shear, the shear levels are going to be approaching record levels for the Carolina's. Thus Damaging winds and a few tornadoes are certainly likely. A QLCS, which is a fancy name for a squiggly line of storms, will have the greatest threat for damaging winds and embedded Tornadoes. The QLCS will then pose a risk of widespread 40-55 mph winds, locally up to 65-75 mph, and a few mesovortices/tornadoes (embedded tornadoes). Additionally, forecast environmental parameters suggest the potential for a significant tornado.
Environmental conditions ahead of the front look dangerous to say the least, with efficient enough instability (1000 - 1500 J/KG ML CAPE), dangerous model shear (Bulk: 45 to 55kts; SFC -> 1km: 20 - 30kts) and helicity values, and near record PWat values (1.5 inches +). Assuming at least some surface heating is allowed between the pre-frontal showers, the environment looks prime for a very active weather day across the Carolinas. A quick overview of each threat is below.
THREATS: Based on the current model analysis, all types of severe weather is expected. Damaging winds look to be the greatest threat, however, the threat for tornadoes also is possible. Models are showing discrete supercells out ahead of the main line over / Central/Eastern NC, this trend will be monitored for Tornadoes. As always with all storms, large hail is possible too. The timing of these storms will be from mid- late afternoon to the overnight hours in Central and Eastern NC, and mid-morning through early afternoon in the mountains/ Triad.
TORNADOES Models continue to spit out some alarming low and mid- level shear values which, if realized, would easily support the formation of a few tornadoes across Central and Eastern NC. Still some uncertainty on favored locations at this point, likely dependent in large part to surface heating ahead of the line and the eventual strength and placement of the meso-low and attendant triple point. For now, best Tornado values seem to be centered across the southern Sandhills and Coastal Plain counties. However, Tornadoes could be possible anywhere east of i77 but a better chance in areas above. I’ll have a Tornado Threat number map out tomorrow morning!
FLASH FLOODING: Saturated soils abundant across central NC, Flash Flooding will certainly be a concern again with this system, especially in and around urban centers Areas that see training storms will be of primary concern. Eventually, the 1 - 1.5 inch areal average equals 2-3” of rain with this system will transition into the already swollen rivers/lakes, likely causing additional or at least prolonging river flooding across central NC into the weekend. This is generally supported by both GEFS/NAEFS Ensemble River Forecasts, with additional flooding especially likely along the Neuse and Haw Rivers through the weekend, possibly lasting into next week
TIMING: Mountains to the Triad will be from 8AM-1PM the rest of the state will be 1PM-10PM, see a another post for more details on Facebook!
WHAT TO DO: Don't freak out I got you covered! Please stay tuned for updates as things and will change, 24/7 updates throughout the storms will occur on North Carolina's Weather Authority. I am closely monitoring the situation, make sure you have many ways to receive severe weather alerts on Friday. It is imperative that you keep checking for updates tomorrow. Questions please message on the Facebook page not on the website!
CALL TO ACTION: People must have a way of hearing warnings, and that way should never, ever be a siren. Their purpose is only to reach a limited number of people outdoors. Every North Carolina home and business must have a NOAA Weather radio, properly programmed and with a fresh battery backup. Be sure WEA (Wireless Emergency Alerts) are enabled on your phone (check notification settings)... even with no good weather app installed you will receive a tornado warning with a loud audible alert.
If you live in a manufactured home, you have to GET OUT if a tornado warning is issued. Have a shelter identified, or other place identified that is open when you are at risk. Know how to get there quickly.
SEVERE WEATHER TEXT ALERTS
I want to remind you with severe weather and hurricane seasons coming up, to sign up for our FREE text alert service! Texts reach you when you have little cell service and you don't have to download anything and take up storage. This is not automated - I am constantly monitoring warnings. That is our priority: your safety. You will only receive alerts for the counties in which you subscribe to. You are welcome to signup/subscribe to as many counties as you wish to and can unsubscribe at any time.
To sign up you will still need to make sure your text (in your cell phone text messages) the EXACT spelling of the capitalized word on the list BELOW to 84483 to sign up for that county.
I have added 100 NC counties out of 100 counties, As always all warnings and watches will be posted on FB for all 100 counties.
(this is exactly how you have to text your county in your cell phone text messages to 84483 to sign up). ALAMANCECOWX ALEXANDERCOWX ALLEGHANYCOWX ANSONCOWX ASHECOWX AVERYCOWX BEAUFORTCOWX BERTIECOWX BLADENCOWX BRUNSWICKCOWX BUNCOMBECOWX BURKECOWX CABARRUSCOWX CALDWELLCOWX CAMDENCOWX CARTERETCOWX CASWELLCOWX CATAWBACOWX CHATHAMCOWX CHEROKEECOWX CHOWANCOWX CLAYCOWX CLEVELANDCOWX COLUMBUSCOWX CRAVENCOWX CUMBERLANDCOWX CURRITUCKCOWX DARECOWX DAVIDSONCOWX DAVIECOWX DUPLINCOWX DURHAMCOWX EDGECOMBECOWX FORSYTHCOWX FRANKLINCOWX GASTONCOWX GATESCOWX GRAHAMCOWX GRANVILLECOWX GREENECOWX GUILFORDCOWX HALIFAXCOWX HARNETTCOWX HAYWOODCOWX HENDERSONCOWX HERTFORDCOWX HOKECOWX HYDECOWX IREDELLCOWX JACKSONCOWX JOHNSTONCOWX JONESCOWX LEECOWX LENOIRCOWX LINCOLNCOWX MACONCOWX MADISONCOWX MARTINCOWX MCDOWELLCOWX MECKLENBURGCOWX MITCHELLCOWX MONTGOMERYCOWX MOORECOWX NASHCOWX NEWHANOVERCOWX NORTHAMPTONCOWX ONSLOWCOWX ORANGECOWX PAMLICOCOWX PASQUOTANKCOWX PENDERCOWX PERQUIMANSCOWX PERSONCOWX PITTCOWX POLKCOWX RANDOLPHCOWX RICHMONDCOWX ROBESONCOWX ROCKINGHAMCOWX ROWANCOWX RUTHERFORDCOWX SAMPSONCOWX SCOTLANDCOWX STANLYCOWX STOKESCOWX SURRYCOWX SWAINCOWX TRANSYLVANIACOWX TYRRELLCOWX UNIONCOWX VANCECOWX WAKECOWX WARRENCOWX WASHINGTONCOWX WATAUGACOWX WAYNECOWX WILKESCOWX WILSONCOWX YADKINCOWX YANCEYCOWX