Tag Archives: East Texas

Severe Weather Expected Tomorrow

A strong upper level storm system along with a southward advancing cold front will slam into a strongly unstable, humid air mass on Thursday across North, Central, and East Texas. A severe weather event is anticipated tomorrow as a line of thunderstorms should develop along an advancing cold front by the mid-afternoon hours. Ingredients will be in place to support the risk of severe thunderstorms capable of producing damaging wind gusts and large hail. The Storm Prediction Center has placed portions of Northeast and East Texas in an enhanced risk of severe weather tomorrow running along and east of US-75 from Sherman to Dallas and north of Interstate 20 from Mesquite to Marshall. A larger area of severe weather risk includes much of North and Central Texas into the Hill Country along with the Brazos Valley and East Texas. Ingredients are coming together for the possibility of a severe weather outbreak with a line of severe thunderstorms.

2014-09-30_23-33-25

An upper level jet will dip south into Texas by the late morning and early afternoon hours tomorrow. By the mid-afternoon this upper level jet should be favorably positioned in conjunction with an advancing cold front. Winds at 500 millibars or about 18,500 feet above sea level will be exceeding 45-55 knots. The minimum wind speed I like to see for more organized thunderstorms is 35-40 knots at 500 millibars so the upper level winds will support an organized convective mode. The reason we look for stronger winds in the upper atmosphere is that the winds will help blow precipitation away from a thunderstorm’s updraft thus allowing warm, unstable air to continue feeding into it. When upper level winds are weak precipitation has a tendency to fall straight down or into the updraft. When precipitation falls back into the updraft the warm/unstable air is cut off and the thunderstorm weakens. During the summer months we refer to those storms as popcorn storms since they go up quickly, produce a light of lightning and heavy rain, but quickly weaken and usually dissipate within 30-45 minutes often resulting in a localized microburst. Since winds tomorrow in the upper levels of the atmosphere should blow rain out of the updrafts we expected a more organized convective mode and longer lived storms.

2014-10-01_17-13-55

If you’ve been outside today you know temperatures are quite hot and muggy. Temperatures are well above average across North Texas today and will be again tomorrow as surface temperatures climb into the lower 90s. One way to measure moisture in the atmosphere is the dewpoint temperature. The dew points this afternoon across the eastern half of Texas are in the 50s, 60s, and even 70s. Honestly today feels like an April or May afternoon which is usually not a good thing when you’re talking about a upcoming storm system in early October. With a very moist atmosphere in place ahead of the cold front tomorrow the atmosphere is going to become strongly unstable. Surface based convective available potential energy (CAPE) values will exceed 2,000 to 3,000 J/Kg by the afternoon hours Thursday. Those are fairly impressive values for October and in combination with the strong upper level dynamics and cold front could support an appreciable severe weather threat.

 

2014-10-01_17-12-29

One unknown factor that is still causing some uncertainty is the actual placement of the cold front when thunderstorms begin developing Thursday afternoon. Some model solutions have thunderstorms developing east of I-35 and keeping the D/FW Metroplex and everyone west of I-35 will remain dry. Other models suggest thunderstorms will begin developing along a Nocona-Mineral Wells-LaLampasasine. The first storms will begin developing across Oklahoma and gradually build south along the cold front. Thus the first storms will develop near the Red River and build south into Texas as the cold front moves east. Hence where the cold front ends up when storms fire will determine exactly where the rain chances begin. Based on current data and the National Weather Service Fort Worth’s thinking the current forecast shows thunderstorms developing just west of the D/FW Metroplex and I-35/I-35W by the mid afternoon hours. Thunderstorm cocoverageill increase as the cold front/squall line moves into D/FW with a nearly solid line of storms by the time they end up east of D/FW and US-75/I-45 in the enhanced risk zone. This could chance and storms could fire further west or east and radically chance the overall storm chances for the D/FW Metroplex.

Due to the combination of favorable ingredients for severe weather once storms get going they will likely become strong to severe quickly with a threat for damaging straight line winds exceeding 60 MPH and hail up to the size of golfballs. Not everyone will be hit by thunderstorms tomorrow. Not everyone who gets a storm tomorrow will receive large hail or damaging winds. The overall setup favors a linear event (squall line) with low level wind shear unidirectional and marginal. The tornado threat will be low but not zero. Any individual thunderstorms that manage to stay by themselves for a while or interact with an outflow boundary could produce hail up to the size of hen eggs and exhibit some rotation. While weak low level winds will keep any tornado threat localized and marginal any supercell storms will have to be watched.

Driest September On Record for D/FW

While significant rains were observed across West and South Texas this month the same cannot be said for North and East Texas. On average D/FW International Airport receives 2.55 inches of rain during the month of September. The current driest September on record was set in 1984 with only 0.09 inches of rain in September. So far we’ve seen just 0.06″ of rain this month. With no precipitation expected through Wednesday this month is expected to set a new record low for rain during the month of September.

2014-09-29_19-52-55

10687062_740169709352978_8360106317375640416_n

The National Weather Service in Fort Worth has put together an excellent resource page regarding the ongoing drought and expectations for this fall. Be sure to check it out at http://www.srh.noaa.gov/fwd/?n=drought
We also have the 2014-2015 Winter Outlook for Texas published on our blog here.

Midday Notes on Today’s Severe Weather

Let me start out this noon update by saying we currently have no severe weather in the state this morning. We did have a potent severe thunderstorm set up over Van Zandt county between 9 and 10 AM with gusty winds and brief rotation. As of 12 PM we have a large area of light to moderate precipitation across East Texas. The strongest cores in this precipitation shield are producing cloud to ground lightning and heavier rain. Isolated heavy shows continue across parts of the D/FW Metroplex where temperatures have remained in the low to mid 70s after precipitation earlier this morning.

I’ll also say today is NOT expected to be a big tornado day. Low level winds are simply too weak to support a high-end tornado threat. The two primary severe weather hazards will be large hail and damaging wind gusts. While a few tornadoes are certainly possible I want to emphasis there is no reason to be worried or scared.

So how does the rain earlier this morning impact the severe weather setup later this afternoon? Well there have been a couple changes that we’ll talk about. The primary implication from this morning’s storms is an outflow boundary that has pushed south of the D/FW Metroplex to between Hillsboro and Waco. On the north side of this boundary surface temperatures are about five to ten degrees cooler than to the south of the boundary where temperatures have climbed into the 80s. Overall this results in the most significant severe weather threat shifting a bit south. As such the severe weather outlooks have been adjusted accordingly from the Storm Prediction Center.

Speaking of severe weather outlooks let’s take a look at the brand new one just issued! I’m doing something different now in that I’ve created graphics for each specific severe weather hazard including the potential for tornadoes, large hail, and damaging wind gusts. The result is three different graphics depicting each severe weather hazard versus just the overall risk today. This means you may have an enhanced risk for damaging wind gusts this evening but a low tornado threat for example.

2014-06-12_11-37-58

2014-06-12_11-38-20

2014-06-12_11-39-25

Overall there is an enhanced risk of severe weather across Central Texas, parts of North Texas, and East Texas later today. As rain continues to move out early this afternoon the atmosphere should begin to quickly destabilize. South of the outflow boundary where temperatures have warmed into the 80s the atmosphere is already priming itself. The most significant severe weather threat today could evolve in Central Texas along and south of this outflow boundary where the atmosphere will be extremely unstable. Initial thunderstorms may develop as soon as 3 PM (or in the 4-5 PM timeframe). These discrete storms will likely be supercellular with a threat of very large hail, damaging wind gusts and even the possibility of a tornado or two.

As thunderstorms congeal later this evening into one or more complexes or clusters the threat for damaging wind gusts will increase while the threat for very large hail will decrease. Storms will likely move in an eastward fashion with dominant storms turning to the east/southeast. We’re continuing to monitor trends early this afternoon for signs of mesoscale factors such as small outflow boundaries or other atmospheric phenomena that could locally enhance any severe weather threat. For now I’ll leave you with the meteorological discussion from the Storm Prediction Center regarding the latest severe weather threat for today. I’ll have another update out around 2 PM which will be more specific regarding short-term trends. For now we’re in a waiting game.

…SUMMARY…
SEVERE THUNDERSTORMS ARE EXPECTED ACROSS PORTIONS OF TEXAS EASTWARD
INTO THE LOWER MISSISSIPPI VALLEY. VERY LARGE HAIL AND DAMAGING
WINDS WILL BE THE MAIN THREATS…BUT A FEW TORNADOES ARE POSSIBLE.
ADDITIONAL…BUT MORE ISOLATED…STRONG TO SEVERE STORMS WILL BE
POSSIBLE IN THE NORTHERN AND CENTRAL ROCKIES…THE HIGH PLAINS…AND
ACROSS PARTS OF MID-ATLANTIC STATES TO LOWER GREAT LAKES REGION.

…SOUTHERN PLAINS TO LOWER MS RIVER VALLEY…
THE DECAYING REMNANTS OF AN MCS/TRAILING COLD POOL CONTINUE TO
SPREAD SOUTHEASTWARD ACROSS PARTS OF NORTH TX/FAR SOUTHERN OK LATE
THIS MORNING. INITIAL SEVERE THREAT THIS AFTERNOON WILL BE IN
ASSOCIATION WITH WHAT MAY BE AN UPSCALE DEVELOPING QUASI-LINEAR
COMPLEX AND/OR AN MCV ACROSS PARTS OF EAST TX INTO LA AND PERHAPS
OTHER PARTS OF THE MID-SOUTH/LOWER MS RIVER VALLEY. THE PRECEDING
AIR MASS ACROSS THE CORRIDOR WILL CONTINUE TO STEADILY
WARM/DESTABILIZE COINCIDENT WITH AMPLE HEATING AND LOWER TO MIDDLE
70S F SURFACE DEWPOINTS. DAMAGING WINDS/BOUTS OF SEVERE HAIL WILL BE
POSSIBLE.

FARTHER WEST…ADDITIONAL INTENSE STORM DEVELOPMENT IS ANTICIPATED
ESPECIALLY ACROSS PARTS OF CENTRAL/WEST-CENTRAL TX INTO LATE
AFTERNOON/EARLY EVENING. THIS WILL BE VICINITY OF THE SYNOPTIC FRONT
IN CONJUNCTION WITH RESIDUAL INFLUENCES OF EARLY DAY
OUTFLOW/DIFFERENTIAL HEATING. THIS SCENARIO WILL LIKELY BE AIDED BY
THE APPROACH OF A SHORTWAVE TROUGH/SPEED MAX…WITH ATTENDANT
STRONGER MID/HIGH-LEVEL WESTERLIES…NOTED TO BE MOVING EASTWARD
OVER NM AT MID-MORNING. SUPERCELLS CAPABLE OF LARGE HAIL AND
POSSIBLY A COUPLE OF TORNADOES WILL INITIALLY BE POSSIBLE…WITH
STORMS LIKELY GROWING UPSCALE AND ADDITIONALLY POSING A DAMAGING
WIND RISK AS THEY SPREAD GENERALLY SOUTHEASTWARD TONIGHT. PENDING
EARLY AFTERNOON TRENDS AND GREATER CONFIDENCE IN A PEAK RISK
CORRIDOR…AREAS SUCH AS WEST-CENTRAL/CENTRAL TX COULD WARRANT AN
UPGRADE TO MODERATE RISK /MAINLY FOR VERY LARGE HAIL/ WITH THE 20Z
DAY 1 UPDATE.

Significant Severe Weather Possible on Thursday

Let me start out by saying the severe weather setup for Thursday will depend on how the atmosphere recovers from storms and clouds tonight. The severe weather outlook for tomorrow will likely be adjusted early on Thursday as it becomes more clear how the setup will evolve. The current outlook is a combination of the latest weather model data along with instinct on how the event will set up based on past events.

The Storm Prediction Center has highlighted an area of enhanced severe weather potential for Thursday afternoon and evening across portions of North, Central, and East Texas. This risk zone includes the D/FW Metroplex, Waco, Hamilton, Killeen, Bryan/College Station, Lufkin, Longview, and Jasper. This zone is where confidence is highest in the development of significant severe weather in the form of hail up to the size of baseballs, damaging wind gusts up to 70 MPH, and possibly one or two tornadoes. Surrounding the enhanced risk zone is an area where a few severe thunderstorms are possible during the afternoon and evening hours on Thursday. Large hail and damaging wind gusts are possible with the strongest storms. Depending on how things evolve tonight there is the possibility that a portion of the enhanced risk zone could be upgraded to a significant risk in addition to the possibility of spatial changes to the overall outlook.

2014-06-11_16-32-17

Just because this is not April or May does not mean we cannot have significant severe weather. On June 13, 2012 the D/FW Metroplex experienced one of the costliest hail storms in history. I personally chased that day and ended up getting chased as the western supercell dropped golf ball to baseball size hail on my house! That setup is actually a bit similar to tomorrow’s setup as an outflow boundary should set up somewhere tomorrow. Wherever that outflow boundary sets up on Thursday will be a focal point for thunderstorm development by the afternoon hours and possibly where a tornado threat may develop as low level wind shear will be enhanced.

Since tonight’s thunderstorm complex could cause changes to tomorrow’s setup I don’t want to go sharing a bunch of simulated radar images that could very well not be remotely close to correct. I’ll say that tomorrow will feature adequate, but not strong winds aloft. As is often the case in June the strongest jet stream winds are well north of Texas. However just because we don’t have very strong winds aloft does not mean we have a lower severe weather risk. The lack of much stronger winds aloft will keep the tornado threat more isolated and likely cause high-precipitation storm modes on Thursday. All that means is that any sort of low level rotation or area of interest to spotters will likely be wrapped up in rain and thus difficult to see.

2014-06-11_17-28-10

One big time reason for the severe weather threat on Thursday will be very high to extreme instability values. Instability in the atmosphere is measured by Convective Available Potential Energy or CAPE. I won’t go into some nerdy explanation on how values are determined. Positive CAPE values indicate that the atmosphere is unstable to a degree and can support rising parcels of air if other ingredients come into place. A CAPE value of 500 indicates the atmosphere is weakly unstable and could support weak thunderstorms. A CAPE value over 1,500 is indicative of moderate instability while anything over 3,000 is considered strong instability. CAPE values on Thursday could exceed 4,000 to 5,000 in some locations which is considered extremely unstable and supportive of explosive thunderstorm develop. Combined with adequate wind shear aloft this extreme instability will most definitely support an organized storm mode with the threat for very large hail. Tomorrow is the kind of day where the strongest supercells can throw out softball size hail. With extreme instability values you can still have issues with a couple of tornadoes even with weak wind shear. If we end up with an outflow boundary enhancing low level wind shear in the vicinity of a storm which is in the extreme instability axis then that storm will have to be watched for low level rotation very carefully.

We’re going to have to monitor trends tonight to see how everything sets up tomorrow. If cloud cover remains in place tomorrow and keeps instability values down then the severe weather threat will be lower. On the opposite side of the spectrum if we have a stronger piece of energy in the atmosphere or slightly higher winds aloft tomorrow the threat for tornadoes could become a bigger problem. Still the main severe weather threat will likely be destructive hail tomorrow.

4 PM Temperature Roundup

Several locations are very near or have hit record high temperatures this afternoon as an early-season heat takes over parts of Texas. Those east of Interstate 35 across East Texas are only dealing with temperatures in the 80s to around 90 degrees. While warm that is cool compared to what’s going on in Northwest Texas.

2014-05-04_16-05-07

As of 4 PM Vernon has hit 100 degrees with surrounding areas not far behind. Wichita Falls has already set a new record high and are sitting at 98°F with Amarillo at 94°F and Lubbock at 95°F. Childress is at 99°F with D/FW International Airport at 94°F. Pecos is at 95°F, San Antonio at 92°F, Houston at 86°F, and Longview at 88°F.

With several hours of daylight left temperatures will likely climb a few more degrees so I expect more triple digit readings by 5 PM. We’ll have a complete list of new or tied record high temperatures later this evening once we’ve set the high temperatures for the day. This should be the warmest day but temperatures will remain hot for the early work week.

@TxStormChasers

/TxStormChasers

Sign Up for Daily Emails!

amb_logo_lrg