Potential for Severe Outbreak on Saturday

[ticka1]

Here is the SPC's 2 day outlook map - which shows us in Texas having the potential for some activity. Jeff - any comments?

[ticka1]

The text outlook from SPC on the 2 day outlook.

SPC AC 250641

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1241 AM CST FRI MAR 25 2005

VALID 261200Z - 271200Z

THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 SSW
LCH 50 S LFK 45 WNW LFK 25 NNE TYR 15 ENE TXK 40 NNE GLH 25 NE CBM
40 NW AUO 40 WNW ABY 30 E MAI PFN.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 E
GLS 15 S CLL 20 WNW TPL SEP 45 SW ADM 20 NW PGO 50 N LIT 10 SW DYR
25 W BNA 30 ESE CSV AND 15 ENE AGS 35 SSE SAV ...CONT... 15 N PBI 15
S SRQ.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 50 ENE PSX 50 N HDO
20 ESE INK 25 SSW ROW 10 NNE 4CR 15 N SAF 50 SSE ALS 35 ENE TAD 20
WSW EHA 45 WSW GAG 45 NE CSM 20 NNE MKO 15 ESE UNO PAH 35 ESE OWB 30
N LOZ 20 SW GSO 20 SSW FAY 20 S CRE.

...THERE IS A MDT RISK OF SVR TSTMS OVER PORTIONS OF EAST
TEXAS...SOUTH ARKANSAS...MUCH OF LOUISIANA...MISSISSIPPI...
ALABAMA...THE WESTERN FLORIDA PANHANDLE...AND A SMALL PART OF
SOUTHWEST GEORGIA...

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN TX ACROSS AR...PARTS
OF TN...NRN MS/AL...GA/FL...AND WRN SC...

WIDESPREAD SEVERE THUNDERSTORMS CAPABLE OF LARGE DAMAGING HAIL...
HIGH WINDS...AND POTENTIALLY LONG-TRACK TORNADOES ARE FORECAST TO
MOVE FROM WEST TO EAST ACROSS PARTS OF THE SOUTH-CENTRAL AND
SOUTHERN U.S. ON SATURDAY.

...SYNOPSIS...
A POWERFUL EARLY SPRING TROUGH IS FCST TO AMPLIFY AND MOVE RAPIDLY
FROM THE SRN ROCKIES TO THE SCNTRL U.S. ON SATURDAY. A BELT OF
STRENGTHENING MID AND UPPER LEVEL FLOW /70-80KT AT 500MB OVER TX BY
SATURDAY EVENING/ WILL BE ASSOCIATED WITH THE AMPLIFYING TROUGH AND
WILL SPREAD EWD ACROSS AN INCREASINGLY WARM AND MOIST AIR MASS FROM
ERN TX ACROSS THE LWR MS VLY DURING THE PERIOD. VERY STRONG FORCING
FOR ASCENT WITHIN THE NOSE OF DIFFLUENT MID LEVEL WIND MAX WILL
PROMOTE SURFACE CYCLOGENESIS ALONG A WARM FRONT SITUATED FROM SERN
TX NEWD INTO LA. AS THE SURFACE LOW DEEPENS AND TRACKS ENEWD ALONG
THE WARM FRONT...WARM SECTOR AIRMASS WILL SPREAD WELL INLAND ACROSS
THE LWR MS VLY AND FUEL WIDESPREAD ORGANIZED TSTMS ACROSS THESE
AREAS DURING SATURDAY AND SATURDAY NIGHT. THE TROUGH AND SURFACE LOW
WILL CONTINUE EAST SATURDAY NIGHT AND INTO EARLY SUNDAY WITH TSTM
ACTIVITY POSSIBLY SPREADING RAPIDLY EAST IN THE FORM OF ONE OR MORE
CONVECTIVE COMPLEXES. SEVERE WEATHER POTENTIAL MAY EXTEND AS FAR
EAST AS NRN FL AND SOUTHEAST U.S. COAST BY SUNDAY MORNING.

...ERN TX INTO AR/LA/MS/AL...
STRONG WARM AIR ADVECTION REGIME IS EXPECTED TO BE ONGOING EARLY
SATURDAY MORNING ACROSS ERN TX AS MID LEVEL HEIGHT FALLS BEGIN TO
SPREAD EAST FROM THE SRN HIGH PLAINS. TSTMS WILL BE MOST LIKELY ON
AND NORTH OF A DEVELOPING WARM FRONT AND SURFACE LOW OVER THE
ARKLATEX REGION. GIVEN STRONG FORCING SPREADING EAST INTO THIS
REGION...AND LIKELIHOOD OF AT LEAST MODEST INSTABILITY AND
PRONOUNCED SHEAR WITHIN THE FRONTAL ZONE...ELEVATED SUPERCELLS
PRODUCING LARGE HAIL ARE EXPECTED.

AIR MASS TO THE SOUTH OF THE MORNING ACTIVITY IS EXPECTED TO BECOME
STRONGLY UNSTABLE BY LATE MORNING. STORMS NEAR THE FRONT/LOW WILL
LIKELY BUILD INTO THIS AIR MASS AND BECOME SURFACE-BASED FROM ERN TX
INTO LA THROUGH THE AFTERNOON. STRENGTH OF LOW LEVEL FLOW...MODEST
CAPPING...AND HIGH BOUNDARY LAYER RH FAVOR THE DEVELOPMENT OF
DISCRETE SUPERCELLS...POSSIBLY BECOMING TORNADIC. ORIENTATION OF
WARM FRONT...AND TRACK OF THE SURFACE LOW WITHIN/NEAR THE FEED OF
ABUNDANT INSTABILITY FURTHER SUPPORTS THE SCENARIO FOR A COUPLE OF
LONG-TRACK TORNADOES OVER THE AREA...IN ADDITION TO VERY LARGE HAIL
AND STRONG/SEVERE WINDS. GIVEN BROAD WARM SECTOR FCST EWD ACROSS THE
LWR MS VLY...IT IS POSSIBLE THAT FAMILIES OF SUPERCELLS WITH CYCLIC
TORNADOES MAY CONTINUE TO DEVELOP EAST INTO MS AND PARTS OF AL
THROUGH THE EVENING.

...TN VLY TO SOUTHEAST...
MAGNITUDE OF LARGE SCALE FORCING FOR ASCENT IS EXPECTED TO MAINTAIN
WIDESPREAD TSTMS FROM LATE SATURDAY EVENING THROUGH SUNDAY MORNING
FROM THE TN VLY EWD TO GA/SC. WHILE THERE IS SOME UNCERTAINTY WITH
REGARD TO NRN AND ERN EXTENT OF SEVERE WEATHER THREAT THROUGH LATE
IN THE FCST PERIOD...MODELS ARE SUGGESTING THE UPSCALE DEVELOPMENT
OF CONVECTION INTO A FAST MOVING SEVERE SQUALL LINE FROM MS/AL EAST
TO GA/SC. ETA IS ALSO FCSTG AN INCREASE IN INSTABILITY AHEAD OF THIS
COMPLEX DURING THE NIGHT...FROM THE FL PNHDL NEWD ACROSS GA AND SRN
SC LATE SATURDAY NIGHT. THUS...FAST MOVING ORGANIZED STORMS MAY
CONTINUE TO PRODUCE TORNADOES... DAMAGING WINDS...AND LARGE HAIL
ACROSS THE NRN GULF COAST AND INTO THE SOUTHEAST INTO EARLY SUNDAY.

...WEST TX...
COLD FRONT WILL SPREAD ACROSS THE TX SOUTH PLAINS EARLY SATURDAY. IF
SUFFICIENT SURFACE HEATING OCCURS AHEAD OF THE BOUNDARY...A FEW
HIGH-BASED TSTMS WITH HAIL COULD DEVELOP BY AFTERNOON.

..CARBIN.. 03/25/2005

[sparky]

Looks active ticka and i will be honest read some severe wx parameters for alabama sunday am and i am quite concerned. What really caught my eye was the significant tornado paremeter which was 4.7 in northeast alabama. Now jeff i am still learning here that is pretty concerning isn't it? Do you think we really have a chance of long tracked tornadoes across the deep south with this system? Also, do you see a high risk from spc being issued?

[ticka1]

Sandy where is the tornado parameter? What does it say for SE texas?

[jeffl]

Significant outbreak of severe weather expected from E TX to GA over the weekend.

Today:

Severe thunderstorms will be possible by late afternoon along a surface front in C to NE TX. Parameters are favorable for supercells with main threats being large hail and damaging winds. Cap greatly increases southward so the seavere threat should be limited to C, N, and NE TX overnight.

Saturday:

Powerful trough begins to eject into TX with strong WAA over most of the Gulf coast. LLJ of 45-55kts will transport 60-65 degree dewpoints as far north as N MS. Impressive dynamics coupled with strong insolation will make for a very rough afternoon and evening from E TX to AL.

Clusters of dangerous supercells will develop within the warm sector. Shear profiles are favorable for all severe modes including long tracked tornadoes.

Air mass over E TX into LA will become very unstable by mid afternoon with high CAPE and high shear in place. Storms will develop along the advancing cold front from near Shreveport. LA to Conroe, TX and move eastward. These storms may form into a line producing widespread wind damage and hail damage. Supercells with a distinct tornado threat will continue to develop well ahead of this line over LA, MS, and AL.

This is a dangerous situation especially since it is a hoilday weekend and some may not be as aware as usual.

Over SE TX moisture is currently limited to below 925mb with a very strong cap in place. It will take a lot of heating and lift to break this cap. I think really only area NE and E of SE TX stand a chance of seeing the bad stuff.

However this may change by tomorrow as we try to moisten the air column.

[sparky]

http://www.spc.noaa.gov/exper/mesoanalysis/s2/index2.html lol still toying with it.

[ticka1]

Jeff if we do have anything break out here - will u be available for nowcasting if we decide to chase?

[jeffl]

I think the chances for SE TX are not that great. Maybe in deep E TX and on into C LA, or at least 100-150 miles NE of HOU. I strongly discourage any storm chasing over E TX due to very poor visibility and a poor road netwrok.

Things may change by the morning however.

As far as nowcasting goes, I will be fairly busy tomorrow, unless things get going within our CWA. I just competely re-landscaped the entire yard so I am finishing that task. So I probably will not be available unless it looks active here in SE TX.

[jeffl]

SPC has issued a Severe Thunderstorm Watch for a large part of SE TX until 200am.

Complex of severe thunderstorms over C TX is progressing much further S than expected. PM soundings from CRP and Del Rio showed a strong cap in place, however supercells over C TX appear to be riding the N edge of the cap. Extrapolation of current storm motion puts these cells into the NW parts of SE TX late this evening. Mean cell on south end of the line has been tornadic and a very efficient hailer so far this evening.

Still think there is capping in place over SE TX so we shall see how far S and E these storms get. If they make it through here, then we may be in serious trouble Saturday as shear profiles are very favorable for supercells and tornadoes. Only low to mid level capping could save us from another severe weather outbreak, and it currently appears the models may be overestimating the cap intensity.

[ticka1]

Jeff, I know you said you have a major project you are needing to complete on Saturday and won't be available much online.....can u keep us updated as much as possible on tomorrow's events....Got a full day of activity planned - don't want to get caught if any bad weather does occur.

[ticka1]

Suzi just called me - she's out chasing tonight - brave lady doing her chasing at night....I giving her information via my level 3 - told her to head between 290 and Interstate 10 for the best positioning if this storm continues on it current track.

[sparky]

http://www.spc.noaa.gov/products/outlook/day1otlk_1200_prt.html

...GULF STATES...

MARITIME TROPICAL AIR MASS HAS SPREAD NORTH ACROSS THE GULF OF
MEXICO AND IS POISED TO SURGE INLAND AHEAD OF DIGGING UPPER TROUGH.
THIS MOISTURE INCREASE WILL INITIALLY BE ASSOCIATED WITH RETREATING
WARM FRONT THAT SHOULD MOVE ONSHORE EARLY IN THE PERIOD AS A WEAK
BUT CLEARLY IDENTIFIABLE UPPER SHORTWAVE TROUGH RACES EWD ACROSS THE
LOWER MS VALLEY REGION. A SECOND MORE SIGNIFICANT UPPER SPEED
MAX...APPROACHING 100KT...WILL TRANSLATE THROUGH THE BASE OF THE
DIGGING UPPER TROUGH ACROSS SOUTH TX...THEN EJECT NEWD INTO LA LATE
IN THE PERIOD. THIS FEATURE WILL SERVE TO SHARPEN THE FRONTAL ZONE
OVER LA/MS AFTER 27/00Z AS SFC CYCLOGENESIS LIFTS NEWD ALONG
BOUNDARY IN RESPONSE TO THE STRONG EXIT REGION.

IT APPEARS WARM ADVECTION ALONG WARM FRONT WILL INCREASE
SUFFICIENTLY TO GENERATE DEEP CONVECTION EARLY IN THE PERIOD ACROSS
THE NERN GULF OF MEXICO. THIS ACTIVITY SHOULD LIFT NEWD WITHIN
STRONGLY SHEARED ENVIRONMENT...BUT RECOVERING BOUNDARY LAYER AIR
MASS. 00Z MODELS ARE IN GENERAL AGREEMENT THAT A BROADENING ZONE OF
INCREASINGLY FAVORABLE REAL ESTATE WILL BECOME SUFFICIENTLY UNSTABLE
FOR SUPERCELL DEVELOPMENT. GIVEN THE NATURE OF THIS EXPECTED
ASCENT...DETAILS AND TIMING OF INITIATION ARE MORE NEBULOUS.
REGARDLESS...ANY STORMS THAT FORM THROUGHOUT THE PERIOD MAY
POTENTIALLY PRODUCE TORNADOES...IN ADDITION TO LARGE HAIL OR
DAMAGING WINDS.
A SOMEWHAT STRONGER SIGNAL IN THIS EVENINGS DATA IS THE EXPECTED
TIGHTENING OF THE BAROCLINIC ZONE ACROSS THE LOWER MS VALLEY
SATURDAY EVENING. IN RESPONSE TO THE STRONG EJECTING UPPER SPEED
MAX...LLJ SHOULD INCREASE AND FOCUS CONVERGENCE ALONG THE ADVANCING
COLD FRONT. FORECAST SOUNDINGS AHEAD OF THE FRONT ARE STRONGLY
SUPPORTIVE OF SUPERCELL DEVELOPMENT AND TORNADOES. ALTHOUGH THERE
MAY BE A LULL IN SEVERE ACTIVITY FOR MUCH OF THE DAY ACROSS PORTIONS
OF THE CENTRAL GULF STATES...WHEN THE ASCENT REGION SPREADS ACROSS
TX INTO LA RAPID THUNDERSTORM DEVELOPMENT SHOULD OCCUR DURING THE
EVENING/OVERNIGHT HOURS. THE DEGREE OF MOISTURE RECOVERY AHEAD OF
SFC LOW WILL DICTATE THE NWD EXTENT OF SEVERE TSTMS...POSSIBLY INTO
THE MIDDLE TN VALLEY REGION. TORNADOES...DAMAGING WINDS AND LARGE
HAIL APPEAR LIKELY WITH THIS ACTIVITY WELL THROUGH THE OVERNIGHT
HOURS.

..DARROW/BANACOS.. 03/26/2005

[stormy]

so jeff how does it look for central Alabame???????????

[sparky]

To sum it up nicely stormy not good. Your name says it all for the next 24 hours or so. Watch already in south Alabama and both day1 and day 2 oulooks have u in moderate risk. Please stay safe.

[stormy]

ticka let us know how suzi is doing and if she spots one. Gosh I would love to be doing that
How come you were not with her chasing?????

[jeffl]

New weather watch expected E and S of WW 85 early this afternoon.

Surface heating is eroding the cap over SE TX and thunderstorms should fire along and ahead of surface low pressure E of I-35 within the next 3-4 hours.

All severe modes are possible.

This will be the begining of the large scale severe weather outbreak tonight.

[jeffl]

so jeff how does it look for central Alabame???????????

Alabama will be under the gun tonight, with the potential for long tracked violent tornadoes

[stormy]

Thank you jeff. Guess I really do need to watch this.

[sparky]

yes it does two PDS watches south an south west of u now storms r exploding gonna be a very dangerous eveining/night across the south. stay safe


http://www.srh.noaa.gov/bmx/data/wxplot/wxplot.html

http://www.spc.noaa.gov/products/watch/

http://www.spc.noaa.gov/products/outlook/day1otlk.html

[stormy]

Thank you sandy for the heads up. got alot todo tonight but will keep watch.

[sparky]

PDS tornado watch for ya kim til 4am stay safe ok

http://www.spc.noaa.gov/products/watch/ww0092.html

[jeffl]

This is a very dangerous situation.

Large violent tornadoes are possible over MS, AL, E LA, and NW Fl tonight.

Warm front currently extends from surface low pressure over C LA into C MS then ESE toward NC FL. Supercells containing tornadoes continue to develop along and south of this warm front including two very nasty tornadic supercells over EC MS right now heading for locations south of Meridan. These cells have produced numerous tornadoes and damage.

850mb LLJ of 30-40kts currently extends from SE LA into C MS and then NE into N AL. Low level winds are backing north of the surface warm front over C MS and C AL creating high helicity values (0-1km of 200-300). 700mb winds are SW at 50kts and 500mb winds are WSW at 60kts creating favorable updraft roatation. Strong nose of upper level jet is currently approaching SE TX with elevated convection. This jet will overspread the very moist and unstable warm sector along with large scale acesnt from main upper trough. This will continue the severe threat throughout the night over the risk area.

This area has had several deadly nocturnal tornado outbreaks and is strongly favored for such events. Heed warnings with fast action since cell motion is 35-50mph. Make sure NOAA weather radios are in the alert mode especially if going to bed.