Wed., 9th of April 08 till Friday 11th outbreak-thread

[CrazyC83]

These cells look to be rapidly getting organized, and I wouldn't be surprised to see them go tornadic by 3 pm...

[Ed Mahmoud]

Bunkertor

2 things, one, a shallow cold layer at the surface, and above it, the dreaded capping inversion.

The cold layer should be gone, as the warm front is about to pass, and then heating of the ground, and cooling of the warm layer, possibly due to increased lift from the upper trough, should allow storms to 'break' the cap eventually.

[RL3AO]

Verne Carlson and Tony Laubach are chasing and Verne has a live stream from his car.

http://streaming.severestudios.com/verne.carlson

Links to their blogs which they keep updated

http://stormchaserco.blogspot.com/
http://www.tornadoeskick.com/blog.html

[6SpeedTA95]

The CAPE and helicity are somewhat offset with the former maximized in the southern portion of the watch box and the latter maximized in the northern part of the watch box. They have be to better collocated in order to get strong, long-lived supercells. Otherwise whatever convection that does form in the high CAPE area will quickly become elevated minimizing any threat of tornadic activity.

On a side note, I'm not really a fan of issuing PDS watches if there isn't ongoing activity because of the high bust potential associated with any mesoscale severe weather events. I understand they do have to err on the side of caution but they do not want to overuse their most serious wording for borderline or highly uncertain events.

I agree, it was also the same forcaster that issued the last PDS.

[CrazyC83]

The CAPE and helicity are somewhat offset with the former maximized in the southern portion of the watch box and the latter maximized in the northern part of the watch box. They have be to better collocated in order to get strong, long-lived supercells. Otherwise whatever convection that does form in the high CAPE area will quickly become elevated minimizing any threat of tornadic activity.

On a side note, I'm not really a fan of issuing PDS watches if there isn't ongoing activity because of the high bust potential associated with any mesoscale severe weather events. I understand they do have to err on the side of caution but they do not want to overuse their most serious wording for borderline or highly uncertain events.

I agree, it was also the same forcaster that issued the last PDS.

He's known to be their most agressive forecaster when it comes to PDS issuances.

[srainhoutx]

FYI Updated aviation AFD out...


AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
1239 AM CDT WED APR 9 2008

.AVIATION...
1239 PM
18Z FWD SOUNDING SHOWS CAP IN PLACE LIMITING CONVECTION. BEST
LIFT/PVA IS TO OUR NORTHWEST THIS AFTN SO IT WILL TAKE A WHILE TO
ERODE THAT CAP. BKN CLOUDS LIMITING HEATING AS WELL SO NEW BEST
GUESS FOR TSTMS AT METROPLEX TAF SITES IS 23Z-03Z...BACK A COUPLE OF
HOURS FROM PREVIOUS TAFS. 84

http://www.weather.gov/view/prodsByStat ... discussion

[Bunkertor]

Bunkertor

2 things, one, a shallow cold layer at the surface, and above it, the dreaded capping inversion.

The cold layer should be gone, as the warm front is about to pass, and then heating of the ground, and cooling of the warm layer, possibly due to increased lift from the upper trough, should allow storms to 'break' the cap eventually.

He, fine. so i got it ! Thanks !

[RL3AO]

Heres the 18z FWD with the cap.

[CrazyC83]

SEVERE THUNDERSTORM WARNING
TXC353-441-092030-
/O.NEW.KSJT.SV.W.0091.080409T1958Z-080409T2030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SAN ANGELO TX
258 PM CDT WED APR 9 2008

THE NATIONAL WEATHER SERVICE IN SAN ANGELO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTHEASTERN NOLAN COUNTY IN WEST CENTRAL TEXAS...
NORTHWESTERN TAYLOR COUNTY IN WEST CENTRAL TEXAS...

* UNTIL 330 PM CDT

* AT 253 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 7 MILES
SOUTH OF TRENT...OR ABOUT 16 MILES EAST OF SWEETWATER...AND MOVING
NORTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
TRENT BY 305 PM CDT...
MERKEL BY 310 PM CDT...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED... ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.


LAT...LON 3252 10017 3252 9984 3228 10008 3235 10028
TIME...MOT...LOC 1958Z 216DEG 26KT 3242 10012

$$

[CrazyC83]

2000Z is a bit delayed - upgrade maybe?

[RL3AO]

2000Z is a bit delayed - upgrade maybe?

I noticed that too. But I would be surprised if they upgraded.

*off to jam F5 over and over*

[Ed Mahmoud]

Heres the 18z FWD with the cap.

I didn't know 18Z soundings could be found at SPC's web page.

[RL3AO]

They update any new soundings each hour.

http://www.spc.noaa.gov/exper/soundings/

[CrazyC83]

Looks like no significant change...

[RL3AO]

Its out. Still MDT.

[CrazyC83]

MESOSCALE DISCUSSION 0600
NWS STORM PREDICTION CENTER NORMAN OK
0307 PM CDT WED APR 09 2008

AREAS AFFECTED...MUCH OF SWRN/SRN THROUGH NRN OK

CONCERNING...SEVERE THUNDERSTORM WATCH 177...

VALID 092007Z - 092100Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 177
CONTINUES.

ISOLATED HAIL WILL REMAIN POSSIBLE WITHIN WW 177...WITH LOCALIZED
HEAVY RAINFALL RATES BEING THE MAIN THREAT.

REGIONAL RADARS INDICATED AN EXPANSIVE AREA OF ELEVATED TSTMS
EXTENDING FROM SWRN/SRN THROUGH NRN OK SPREADING NNE TOWARD SRN KS.
THIS ACTIVITY REMAINS N OF THE RETREATING SYNOPTIC WARM FRONT WHICH
AT 19Z EXTENDED NEWD FROM THE VICINITY OF MAF TO DUA IN SOUTH
CENTRAL OK TO SWRN AND SRN AR. BROAD 35-40 KT SLY LLJ EXTENDING
INTO OK WILL CONTINUE TO PROVIDE MOISTURE RETURN WITH WAA REGIME
MAINTAINING ONGOING TSTM ACTIVITY ACROSS OK INTO SRN KS THROUGH THE
LATE AFTERNOON. GRADUAL WARMING CLOUD TOP TEMPERATURES PER IR
SATELLITE IMAGERY SUGGEST THE UPDRAFTS ARE TENDING TO WEAKEN. THIS
TREND COMBINED WITH WEAK INSTABILITY WILL LIKELY RESULT IN A FURTHER
DECREASE IN THE SEVERE WEATHER THREAT WITHIN WW 177. MOISTURE
TRANSPORT INTO OK WITH PRECIPITABLE WATER VALUES IN EXCESS OF 1 INCH
WILL SUPPORT LOCALLY HEAVY RAINFALL RATES.

..PETERS.. 04/09/2008


ATTN...WFO...TSA...OUN...

34899617 34049776 34189880 34839952 35699951 36329846
36459701 36209624

[CrazyC83]

SPC AC 092004

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0304 PM CDT WED APR 09 2008

VALID 092000Z - 101200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF SRN OK...NRN
TX...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PART OF THE
CNTRL/SRN PLAINS...

...SRN PLAINS...
WARM FRONT CONTINUES TO QUICKLY DEVELOP NWD INTO THE LOW ROLLING TX
PLAINS...WRN N TX AND EXTREME SRN OK. THIS FRONT COULD CONTINUE NWD
INTO PORTIONS OF CNTRL/ECNTRL OK TONIGHT. MEANWHILE...OUTFLOW
BOUNDARY ARCING FROM BIG SPRINGS NWWD INTO SERN NM WILL LIKELY
DISSOLVE ALLOWING WARM HUMID AIR TO ADVECT NWWD INTO PARTS OF THE TX
S PLAINS AHEAD OF THE DRYLINE THROUGH LATE AFTN. THE DRYLINE WILL
MIX EWD ACROSS THE EDWARDS PLATEAU THROUGH THE AFTN.

LARGE BATCH OF PRIMARILY ELEVATED TSTMS CONTINUES TO TRANSLATE NEWD
ACROSS NWRN TX AND OK AT MID-AFTN...TIED TO A WEAK LEAD MID-LEVEL
IMPULSE. THESE STORMS WILL CONTINUE NEWD INTO KS...AR AND MO
TONIGHT. SOME OF THESE STORMS MAY CONTAIN HAIL N OF THE RETREATING
WARM FRONT.

MEANWHILE...ATTENTION TURNS TO CONVECTIVE INITIATION ONGOING ACROSS
THE ERN PERMIAN BASIN INTO THE BIG COUNTRY ALONG/AHEAD OF THE
DRYLINE WHERE TEMPERATURES HAVE RISEN INTO THE 80S. COMBINED WITH
INFLUX OF 60S SFC DEW POINTS...CINH HAS ERODED WITH MLCAPES
INCREASING TO 2000 J/KG. THUS...EXPECT A GRADUAL INCREASE AND
ORGANIZATION OF THE TSTMS THROUGH LATE AFTN. SFC-BASED TSTMS COULD
ALSO INITIATE LATER THIS AFTN NWWD INTO THE SRN PARTS OF THE TX S
PLAINS...THOUGH THIS IS MORE UNCERTAIN.

DEEP LAYER SHEAR WAS ALREADY QUITE STRONG AND THE STORMS FORMING
WILL GRADUALLY BECOME SUPERCELLS WITH VERY LARGE HAIL IN CNTRL/NRN
TX. PRIMARY TORNADO CONCERN WILL BE IN A CORRIDOR ALONG/S OF THE
WARM FRONT WHERE RAPID DESTABILIZATION WAS OCCURRING COUPLED WITH
LOW LCLS AND STRONG LOW-LEVEL TURNING OF THE WINDS. A COUPLE OF
STRONG TORNADOES COULD ACCOMPANY LONGER-LIVED SUPERCELLS IN THE MDT
RISK. STORM CELLS SHOULD MOVE NEWD AT 30-35 KTS THROUGH THE BIG
COUNTRY AND TOWARD WRN N TX...NCNTRL TX AND SRN OK THIS EVENING.
18Z FWD SOUNDING WAS QUITE CAPPED...BUT WITH CONTINUED WARMING AND
APPROACH OF THE SRN ROCKIES IMPULSE...THERMODYNAMIC SET-UP SHOULD
BECOME MORE FAVORABLE AT SUSTAINING ORGANIZED STORMS AS THEY
APPROACH AREAS N OR JUST NW OF THE METROPLEX LATER THIS AFTN/EVE.

AFOREMENTIONED UPR IMPULSE WILL SWING NEWD INTO THE SRN PLAINS
OVERNIGHT. TSTMS WILL LIKELY EXPAND IN AREAS ALONG/N OF THE WARM
FRONT FROM THE TX PNHDL/NERN NM INTO KS/NRN OK. THESE STORMS WILL
LIKELY GIVE LARGE HAIL/GUSTY WINDS. BUT...PRIMARY SVR THREAT SHOULD
REMAIN OVER WRN-NRN TX INTO SRN OK. DEEP LAYER WIND FIELDS
GRADUALLY BACK WITH TIME...SUGGESTING THAT A MIX OF DISCRETE CELLS
AND LEWPS/BOWS WILL EVOLVE LATER TONIGHT IN THE WARM SECTOR...WITH
ACTIVITY BACKBUILDING SWD ALONG THE DRYLINE PSBLY INTO SCNTRL
TX/HILL COUNTRY. TORNADOES WILL REMAIN PSBL...ALONG WITH LARGE HAIL
AND DMGG WINDS ACROSS THESE AREAS.

..RACY.. 04/09/2008

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
CURRENT UTC TIME: 2007Z (4:07PM), RELOAD THIS PAGE TO UPDATE THE TIME

[Ed Mahmoud]

First warnings in the warm sector in Taylor County and whatever that county West of it is.

[CrazyC83]

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN ANGELO TX
312 PM CDT WED APR 9 2008

TXC353-441-092030-
/O.CON.KSJT.SV.W.0091.000000T0000Z-080409T2030Z/
NOLAN TX-TAYLOR TX-
312 PM CDT WED APR 9 2008

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM CDT
FOR NORTHWESTERN TAYLOR AND NORTHEASTERN NOLAN COUNTIES...

AT 311 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING GOLF BALL SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS
LOCATED NEAR TRENT...OR 19 MILES EAST OF SWEETWATER...MOVING
NORTHEAST AT 26 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
MERKEL BY 315 PM CDT...

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM CDT WEDNESDAY EVENING
FOR WEST CENTRAL TEXAS.

LAT...LON 3252 10017 3252 9984 3228 10008 3235 10028
TIME...MOT...LOC 2012Z 217DEG 22KT 3247 10007

$$

[srainhoutx]

First warnings in the warm sector in Taylor County and whatever that county West of it is.

Nolan