Significant Severe Weather Possible (Including Tornadoes) For Dallas-Fort Worth Metro & Central U.S.

Significant severe weather is possible this afternoon from Texas northeastward into southern Illinois. The Storm Prediction Center (SPC) has an enhanced risk for severe thunderstorms in this region (see Fig. 1). The greatest tornado threat appears to be from western Arkansas southwestward through Texoma down into the Dallas-Fort Worth Metro (see Fig. 2).

Fig. 1: Thunderstorm outlook map from SPC
Fig. 2: Tornado probability map from SPC

This afternoon into the evening is when the severe threat for northern Texas, southern Oklahoma and western Arkansas really gets going. Shear is adequate for the region and guidance indicates a few breaks in the cloud-cover after the lunch hour, which will help make the environment more unstable (any prolonged period of sunshine will help aid in more significant severe weather).

Currently (this morning), convection is ongoing across west Texas. This convection will slowly push eastward towards southern Oklahoma/northern Texas late this morning into the early afternoon hours. Through the late morning hours, the main severe threats with this area of convection are damaging winds and large hail. At noon, the area of thunderstorms will be west of I-35 (this is where the more widespread severe threat will be at that hour–see Fig. 3). The area of convection will continue to push east (towards the I-35 corridor) by the early afternoon hours (see Fig. 4). At this time, it appears an isolated tornado threat will increase within the line of storms. Also, ahead of the line of storms, guidance indicates isolated supercells will develop across northern Texas/southern Oklahoma. These storms will likely produce very large hail and tornadoes in northern Texas, southern Oklahoma and western Arkansas.

Fig. 3: Future radar around lunchtime
Fig. 4: Future radar early afternoon

The flash-flood threat is appreciable, too. The Southern Plains have been very wet over the past few weeks so any storm this afternoon will exacerbate flooding.

Rare High Risk Day For Oklahoma and Texas. Tornadoes Likely!

Strong, violent, long-track tornadoes are likely this afternoon and evening for parts of Oklahoma and Texas. A dryline will advance east this afternoon from southern Kansas, south through western Oklahoma into western Texas/the Texas Panhandle. This dryline will act as an initiation focus for new afternoon convection. Any storm that develops off of the dryline will quickly become severe, as it moves eastward, posing a threat for strong tornadoes, very large hail and damaging winds. Of even more concern is a warm front. The warm front is currently near the Red River lifting northward this morning. The warm front will lie somewhere across central Oklahoma (possibly just north of I-40). This boundary will act to significantly increase low-level shear, which will enhance the tornado threat in the vicinity of the front. The best chance for tornadoes will be across western and central Oklahoma, the eastern Texas Panhandle and northwestern Texas. A lesser tornado threat exists elsewhere.

Currently (this morning), there is ongoing convection across parts of the Texas/Oklahoma Panhandles as well as in western Oklahoma. This convection will continue over the next few hours. These storms are not the high-impact tornadic producing storms mentioned. The morning storms will mainly pose a heavy rain and hail threat. The high-impact severe storms should develop early this afternoon (around Noon) in western Texas/the eastern Texas Panhandle and move east. Significant severe storms will also develop along the warm front in central Oklahoma around this time. The severe threat (including tornadoes) will continue into the nighttime hours due to a strong low-level jet.

The Storm Prediction Center (SPC) has a high risk of severe storms for parts of Texas and Oklahoma (see Fig. 1). The high risk includes the OKC Metro, Stillwater, Ada as well as Lawton (see Fig. 2). A moderate risk includes Tulsa, Ardmore, Atoka and Wichita Falls. Strong tornadoes are likely in the high and moderate risk areas. High risk days are extremely rare! Please note, severe weather is also possible in the slight and marginal risk areas.

Fig. 1: SPC’s thunderstorm outlook map (Today)
Fig. 1: SPC’s thunderstorm outlook map (Oklahoma focus)

As the storms move east of I-35 overnight, a large complex is likely, which will produce damaging winds, small hail and isolated tornadoes. Isolated flash flooding is also possible. Please make sure you have a plan in place if you live in this region in case a watch and/or warning is issued for your area. Do not be afraid, just be prepared!

Strong, violent, long-track tornadoes possible tomorrow

Strong, violent, long-track tornadoes appear possible tomorrow (Monday) afternoon and evening for parts of the Southern Plains. A dryline will advance east tomorrow afternoon from southern Kansas, south through western Oklahoma into western Texas/the Texas Panhandle. This dryline will act as an initiation focus for afternoon convection. Any storm that develops off of the dryline will quickly become severe posing a threat for tornadoes, large hail and damaging winds. Of even more concern is a warm front that will lie somewhere across central Oklahoma (possibly just north of I-40). This boundary will act to increase low-level shear, which will enhance the tornado threat in the vicinity of the front.

The best chance for tornadoes will be across western and central Oklahoma, the eastern Texas Panhandle and northwestern Texas. There will be morning convection across the Texas/Oklahoma Panhandles as well as in southern/central/northern Oklahoma. These storms will mainly pose a heavy rain and hail threat. The severe storms should develop after 2:00PM in western Kansas, western Oklahoma and northwestern Texas/the eastern Texas Panhandle. These storms will advance east through the afternoon evening hours. Unfortunately, it appears the severe threat will continue into the nighttime hours, so tornadoes are possible until around midnight.

Due to the elevated severe threat tomorrow, the Storm Prediction Center (SPC) has a moderate risk of severe storms for parts of Texas and Oklahoma, and an enhanced risk for arts of Kansas, Oklahoma and Texas (see Fig. 1). The moderate risk includes the OKC Metro as well as Enid, Lawton, Childress and Wichita Falls. The enhanced risk includes Tulsa, Ardmore, Amarillo and Abilene. Strong tornadoes are likely in the moderate and enhanced risk areas. Please note, severe weather is also possible in the slight and marginal risk areas.

Fig. 1: SPC’s thunderstorm outlook map (Monday)

As the storms move east of I-35 overnight, a large complex is likely, which will produce damaging winds, small hail and isolated tornadoes. Isolated flash flooding is also possible. Please make sure you have a plan in place if you live in this region in case a watch and/or warning is issued for your area. Do not be afraid, just be prepared!

First Tropical Storm (Andrea) Of The Season To Develop East Of Florida?

Firsthand Weather is keeping a close eye on an area of convection east of the Bahamas this morning for tropical development over the next few days (see Fig. 1). This area of convection is expected to continue to expand and organize as it moves towards an area of lower environmental shear (see Fig. 2), and a low should develop by Monday.

Fig. 1: Current satellite imagery of convection
Fig. 2: Wind shear analysis (University of Wisconsin)

Once the low develops, it is possible further organization and intensification may occur, leading to this season’s first tropical depression or tropical storm. The National Hurricane Center (NHC) has given this area of convection a 30% chance of tropical development over the next 48 hours and a 40% chance of tropical development over the next 5 days (see Fig. 3).

Fig. 3: NHC’s discussion and development chances

Luckily, a ridge to the west/northwest will protect the East Coast from an impact (if development occurs), thus, allowing this system to move towards the northeast (see Fig. 4). If this area of convection obtains tropical characteristics, it would receive the first name of the 2019 Atlantic hurricane season: Andrea. It appears environmental shear will increase by mid-week, which will prevent “Andrea” from getting too strong.

Fig. 4: Ridge in place protecting the U.S. from impacts

Severe Weather Likely Late Week Into Weekend

An active severe weather period will return to the Southern Plains, Plains and Mid-South late this upcoming week into the weekend (Friday through Sunday).

By Friday, a trough will approach the Plains from the west (see Fig. 1). This will spread decent shear into the Southern Plains and allow a ‘sharp’ dryline to take shape. Good moisture will advect ahead of this dryline with dewpoints in the 60s & 70s by Friday afternoon (see Fig. 2). The states that look to be under fire Friday afternoon are: Texas, Oklahoma and Kansas as thunderstorms develop along the dryline.

Fig. 1: Trough Approaching Plains Friday Afternoon
Fig. 2: Future Forecast Dewpoints Friday Afternoon

Due to the favorable setup for severe thunderstorms, the Storm Prediction Center (SPC) has already highlighted a slight risk area for western Kansas, western Oklahoma and western Texas for Friday afternoon/evening (see Fig. 3).

Fig. 3: Friday’s Thunderstorm Outlook From The SPC

By Saturday afternoon, the dryline will move east (closer to the I-35 corridor) allowing the severe weather threat to shift east into northern & central Texas, central and eastern Oklahoma and eastern Kansas (see Fig. 4).

Fig. 4: Future Forecast Dewpoints Saturday Afternoon (Dryline Just West Of I-35 Corridor)

Heading into Sunday, the severe threat will shift east into Arkansas, Louisiana and Mississippi. At this time, it appears widespread severe thunderstorms are possible each day (Friday through Sunday). While this event is still severe days out, there is enough confidence to introduce the possibility of tornadoes, damaging winds, large hail and flash flooding each afternoon during this time period. As the event nears, and certain details become more clear, we can pinpoint which areas will have the greatest chance to see tornadoes.

Cool and Dry Pattern Will Briefly Replace Muggy Airmass Early Next Week

As I alluded to in yesterday’s article, a cooler and considerably less humid airmass will replace the stormy and humid one this weekend. Deep, southwesterly flow currently extends from Texas to the Mid-Atlantic. With low-level southerly and southeasterly flow south of a stationary front draped from southeast Texas to Virginia, the atmosphere has remained moisture-laden. Any embedded disturbance within the deep-layer southwesterly flow has continued to favor the development of storms capable of producing heavy rainfall rates for quite a few.

Deep, southwesterly flow currently exists from the Southern Plains to the Mid-Atlantic

A strong shortwave trough currently moving into the Northern Plains will trek eastward and usher in a pattern change. By early next week, the stationary front will push out, and a longwave trough will temporarily be placed over the eastern U.S. This type of pattern favors cooler and less humid conditions. Temperatures will still reach the 70s and 80s during the day across the South, but nighttime temperatures will actually be a bit chilly. The Northeastern U.S. will eventually have the coolest conditions once the upper-level low passes across the region around mid-week.

Projected departure from average temperatures on Monday morning, May 13
Projected departure from average temperatures on Tuesday morning, May 14
Projected departure from average temperatures on Wednesday morning, May 15

Enjoy it while you can. Expect a warming trend from west to east late week into early next weekend.

Flash Flooding Risk Will Expand Into Southeast and Mid-Atlantic This Weekend

Over the last several days, a longwave trough has remained in place across the western U.S., while a ridge has dominated the pattern across the eastern third of the U.S. Between these two larger-scale features, smaller shortwave impulses have generated favorable conditions for excessive rainfall amounts across parts of the Southern Plains and mid-south.

Rainfall amounts over the last 3 days

Over the weekend, a northern stream shortwave trough will dig into the Northern Plains and move into the Great Lakes by late weekend. This feature will usher in a pattern change and begin breaking down the ridge that has been placed across the Southeast and Mid-Atlantic. Before the cold front associated with the northern system pushes through the Gulf Coast and East Coast states early next week, a period of widespread moderate to heavy rain will fall across a large region of the southern U.S. and extend into parts of the Mid-Atlantic.

Projected 3-day rainfall amounts

Since the northern stream system will begin flattening and weakening the ridge, there will be an eastward expansion of the rainfall and potential flooding risk. Deep, tropical moisture will advect northward and northeastward throughout the weekend; thus, any rain that falls could be heavy and tropical in nature. The next three graphics outline the flash flooding risk for today (Friday), Saturday, and Sunday. Notice how the flash flooding risk will begin shifting eastward with time.

Flash flooding risk for Friday, May 10, 2019
Flash flooding risk for Saturday, May 11, 2019
Flash flooding risk for Sunday, May 12, 2019

Any additional rainfall that occurs across southeast Texas and southern Louisiana today will become problematic given recent heavy rain over the last 24 hours. This includes the Houston and Baton Rouge areas. States east and north of Alabama have remained relatively dry compared to the region just west. Even though soils are quite a bit drier east of the mid-south, high rainfall rates will still result in localized flash flooding farther east. By Sunday, lower rainfall rates will be necessary to cause flash flooding concerns, due to prior rainfall today and Saturday.

Even though I didn’t explicitly mention all regions under a flash flooding risk, please refer to any maps included in this article and future maps we post on social media. The purpose of this article is mainly to give you a heads up on this wet and stormy pattern, especially with Mother’s Day being this Sunday.