TX Severe/Heavy Rainfall Threat

[jeff]

Increasing moisture as ridging pushes to the SE US will help to set up the infamous dry line Sunday afternoon and evening over NC TX.

Moisture return is well underway this morning with low 60 degree dewpoints moving into the coastal counties and spreading northward. Pressure falls in the lee of the Rockies will help surge this moisture northward today and tonight on an increasing low level jet. Surface dry line will sharpen over W TX early Sunday and move eastward during the day as a short wave passes in the SW flow aloft. Lots of cirrus will keep a lid on any heating and mid level capping may be hard to break, however shear values are supportive of severe thunderstorms should any develop during the late afternoon across N TX.

Extended:

Highly active pattern will continue through the week as a large upper low remains anchored over the SW US with the sub-tropical jet positioned over TX. Various short waves will ride across the state producing periods of showers and thunderstorms. Next cold front enters the pictures around Wed or Thurs. of next week. Upper level SW flow will make it a very slow mover and jet dynamics show good position for a favorable heavy rain event. We could see severe and flooding issues from late Tues through Thurs. over a good part of the state. Low level cold air mass finally slides off the coast by late Thurs., but SW upper level flow overruns this cold air resulting in more rain into next weekend.

Another wet period shaping up for an already soggy area.

[Brett Adair]

NAM/ETA is overdoing instability. Some isolated severe is almost a given with this type of shear environment, but I would go with the WRF when it comes to the instability. Nice UVV fields will help to lift any unstably air that is in place. Some nice damage wind gusts and descent hail can be expected with the stronger storms.

[TexasStooge]

Code: Select all

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FORT WORTH TX
453 AM CST SAT FEB 19 2005

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-192200-
ANDERSON-BELL-BOSQUE-COLLIN-COMANCHE-COOKE-CORYELL-DALLAS-DELTA-
DENTON-EASTLAND-ELLIS-ERATH-FALLS-FANNIN-FREESTONE-GRAYSON-HAMILTON-
HENDERSON-HILL-HOOD-HOPKINS-HUNT-JACK-JOHNSON-KAUFMAN-LAMAR-LAMPASAS-
LEON-LIMESTONE-MCLENNAN-MILAM-MILLS-MONTAGUE-NAVARRO-PALO PINTO-
PARKER-RAINS-ROBERTSON-ROCKWALL-SOMERVELL-STEPHENS-TARRANT-VAN ZANDT-
WISE-YOUNG-
453 AM CST SAT FEB 19 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...
THERE IS A CHANCE OF THUNDERSTORMS ACROSS NORTH TEXAS TODAY AND
TONIGHT. THUNDERSTORMS ARE NOT EXPECTED TO BECOME SEVERE...BUT
LIGHTNING WILL PRESENT A HAZARD.

.DAYS TWO THROUGH SEVEN...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SUNDAY AFTERNOON AND
EVENING...GENERALLY EAST OF THE I-35 CORRIDOR. THE PRIMARY THREAT
APPEARS TO BE FROM DAMAGING STRAIGHT LINE WINDS...LARGE HAIL...AND
CLOUD TO GROUND LIGHTNING.

THERE WILL BE YET ANOTHER CHANCE OF THUNDERSTORMS TUESDAY AND
WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED THROUGH TONIGHT.

[Brett Adair]

LOL....looks like Fort Worth agrees with my thinking 100 percent. Heavy rainfall of 1-2"+ could be a problem as well across the region.

[jeff]

Agreed, that instablity will be lacking, however return of mid 60 degree dewpoints already to the coastal bend is a little quick on the moistening.

Moistening alone will not be enough and Feb sun angle is still fairly low along with thick cloud cover. There may be just strong to minimal severe thunderstorms Sunday afternoon.

However, if there is any clearing behind the S/W over W TX currently then we may be able to get 500 J/kg by late afternoon over N TX. There was a similar setup last Sunday that produced a cluster of severe storms from E of CLL to Liberty (driven by 3-4 hours of clearing).

We will have to see how quickly the warm front moves northward tonight (it should also be noted the returning warm air is highly modified and has origins in the SE US and not the Car.)

[TexasStooge]

Well, won't be seeing any severe weather tomorrow.

http://www.spc.noaa.gov/products/outlook/day2otlk.html

[Brett Adair]

I still think there will be some storms along the forcing axis where instability will be the greatest. Looks like the best vertical motion will be further north on the nose of the LLJ axis which will keep the best dynamics away. Still, expect to see some action which will probably come in the form of linear activity. I still expect some storms to go severe down that way in an isolated fashion.