2008 Severe Weather Thread

[Ed Mahmoud]

Fairly small SLIGHT RISK area centered near and just East of DFW

...SRN PLNS/ARKLATEX...
50 TO 60 KT SSWLY LLJ WILL ALLOW PARTIALLY MODIFIED GULF AIR TO
SPREAD RAPIDLY NNE INTO CNTRL/ERN PORTIONS OF TX AND OK LATER
TODAY/TONIGHT. MOISTURE LIKELY WILL REMAIN SOMEWHAT LIMITED WITH
THIS SYSTEM. BUT PWS IN SLIGHT RISK AREA SHOULD INCREASE TO AROUND
.75 TO 1.OO INCH...WITH SFC DEWPOINTS RISING INTO THE MID/UPR 50S F
OVER SRN OK/N TX...AND INTO THE LWR 60S F IN E CNTRL TX BY TONIGHT.

BAND OF STRONG UVV ASSOCIATED WITH EJECTING VORT WILL ENTER THE SRN
HI PLNS THIS AFTN...POSSIBLY ACCOMPANIED BY HIGH-BASED TSTMS GIVEN
FAVORABLE TIME OF DAY AND EXISTING STEEP LOW TO MID LVL LAPSE RATES.
THIS ACTIVITY SHOULD SPREAD RAPIDLY ENE AHEAD OF THE VORT...AND MAY
BE JOINED BY ADDITIONAL DEVELOPMENT ALONG LEE TROUGH/DRY LINE OVER
PARTS OF CNTRL OK AND NRN/CNTRL TX. THE STRONGEST STORMS MAY FOCUS
INVOF I-35 IN N TX AS THE FORCING GLANCES NW FRINGE OF RETURNING
MOISTURE PLUME.

EXPECTED NARROW AXIS OF INSTABILITY ACROSS N CNTRL TX INTO ADJACENT
PARTS OF OK SHOULD BE SUFFICIENT FOR SUSTAINED UPDRAFTS...WITH WIND
PROFILES SUGGESTING GOOD LIKELIHOOD FOR ORGANIZATION INTO BROKEN
LINES. WITH 70 KT MID LVL JET...A FEW SEMI-DISCRETE OR EMBEDDED
SUPERCELLS APPEAR LIKELY...ESPECIALLY BETWEEN ABOUT 00Z AND 06Z.
THESE STORMS COULD YIELD HIGH WIND...HAIL AND PERHAPS A COUPLE
TORNADOES...AND SHOULD SPREAD GENERALLY E/NE INTO NE TX/SRN OK LATER
TONIGHT/EARLY TUESDAY.

FARTHER N...SVR THREAT APPEARS MORE CONDITIONAL ON THE NWD TRANSPORT
OF MOISTURE INTO ERN AND NERN OK. NEVERTHELESS... STRENGTH OF
FORCING AND LIKELIHOOD FOR AT LEAST NEARLY SFC-BASED STORMS SUGGEST
AT LEAST A LIMITED THREAT IN THAT REGION...ESPECIALLY LATER
TONIGHT/EARLY TUESDAY.

..CORFIDI.. 12/08/2008

[somethingfunny]

Slight risk??? Well here in Pottsboro I'm about to get into my bathtub with my dog and a mattress. Wish me luck and I will return in about 30 minutes if my electricity and roof remain on.......

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
1036 PM CST MON DEC 8 2008

TXC181-090500-
/O.CON.KFWD.TO.W.0061.000000T0000Z-081209T0500Z/
GRAYSON TX-
1036 PM CST MON DEC 8 2008

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1100 PM CST FOR CENTRAL
GRAYSON COUNTY...

AT 1036 PM CST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
DEVELOPING TORNADO. THIS TORNADO WAS LOCATED 5 MILES NORTH OF
SOUTHMAYD...MOVING NORTHEAST AT 40 MPH.

THE TORNADO WILL BE NEAR...
POTTSBORO BY 1045 PM CST...
DENISON AND EISENHOWER STATE PARK BY 1050 PM CST...
TAKE COVER IN A BASEMENT...OR ON THE LOWEST FLOOR OF YOUR HOME IN AN
INTERIOR CLOSET OR BATHROOM. USE BLANKETS OR PILLOWS FOR COVER.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 300 AM CST
TUESDAY MORNING FOR NORTHEASTERN TEXAS.

[JonathanBelles]

Yikes! good luck!

[somethingfunny]

The rain's tapering off. That was close. I wasn't even paying attention to the weather....a friend of mine from DFW texted me to be careful and I had no idea what he was talking about until I checked the NWS site. Thank God for him.

Need to get an NWS radio. The "slight risk" news reports left me with my guard down, more worried about icy roads tomorrow morning.

[iorange55]

The rain's tapering off. That was close. I wasn't even paying attention to the weather....a friend of mine from DFW texted me to be careful and I had no idea what he was talking about until I checked the NWS site. Thank God for him.

Need to get an NWS radio. The "slight risk" news reports left me with my guard down, more worried about icy roads tomorrow morning.

Tornado warning for Collin county now. Pretty nasty storms. All we got in Dallas was some rain, seems to be more intense to the north.

[Bunkertor]

Uahm, morning guys !

[somethingfunny]

The rain's tapering off. That was close. I wasn't even paying attention to the weather....a friend of mine from DFW texted me to be careful and I had no idea what he was talking about until I checked the NWS site. Thank God for him.

Need to get an NWS radio. The "slight risk" news reports left me with my guard down, more worried about icy roads tomorrow morning.

Tornado warning for Collin county now. Pretty nasty storms. All we got in Dallas was some rain, seems to be more intense to the north.

Yep. The storm is in the less densely populated areas of eastern Collin County...still prompted me to make a few warning calls to friends out that way. Hopefully no real damage or injuries result from this surprise mini-outbreak.

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
1130 PM CST MON DEC 8 2008

TXC085-090600-
/O.CON.KFWD.TO.W.0062.000000T0000Z-081209T0600Z/
COLLIN TX-
1126 PM CST MON DEC 8 2008

...A TORNADO WARNING REMAINS IN EFFECT UNTIL MIDNIGHT CST FOR
NORTHEASTERN COLLIN COUNTY...

AT 1126 PM CST...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
DEVELOPING TORNADO. THIS TORNADO WAS LOCATED NEAR PRINCETON...MOVING
NORTHEAST AT 40 MPH. SPOTTERS REPORT A WELL DEFINED WALL CLOUD WITH
THIS STORM. EARLIER...SMALL LIMBS WERE REPORTED DOWNED NEAR JUPITER
AND BETHANY ROADS BY WINDS IN EXCESS OF 50 MPH.

THE TORNADO WILL BE NEAR...
FARMERSVILLE BY 1130 PM CST...
BLUE RIDGE AND WESTMINSTER BY 1140 PM CST...

TAKE COVER IN A BASEMENT...OR ON THE LOWEST FLOOR OF YOUR HOME IN AN
INTERIOR CLOSET OR BATHROOM. USE BLANKETS OR PILLOWS FOR COVER.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 300 AM CST
TUESDAY MORNING FOR NORTHEASTERN TEXAS.

LAT...LON 3337 9637 3334 9637 3335 9632 3334 9630
3314 9629 3315 9652 3319 9656 3324 9656
3340 9643
TIME...MOT...LOC 0526Z 228DEG 34KT 3321 9651

[Ed Mahmoud]

Bienville and DeSoto Parishes under a tornado warning...

[TexasStooge]

The National Weather Service will survey the damage in Collin and Grayson Counties to determine if in fact a tornado has touched down.

[Bunkertor]

Crazy, they just upgraded

[Dave]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0656 AM CST TUE DEC 09 2008

VALID 091300Z - 101200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF NRN LA AND SRN AND
CENTRAL MS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS
VALLEY...

...SYNOPSIS...
MAJOR TROUGH CONTINUES TO EVOLVE OVER CENTRAL U.S. LEAD S/WV HAS
RACED RAPIDLY NEWD FROM SRN PLAINS TO LOWER MO VALLEY OVERNIGHT WITH
STRONG WIND MAX/TROUGH CONTINUING TO DIG SEWD FROM AZ/NM INTO S TX
TONIGHT. THIS WILL MAINTAIN A STRONG SWLY FLOW FROM S TX TO LOWER
MS VALLEY INTO TONIGHT. COLD FRONT WRN MO SWWD TO SWRN TX WILL
CONTINUE SEWD MOVING OFFSHORE TX COAST LATER THIS EVENING.

LOW LEVEL MOISTURE FROM WRN GULF CONTINUES TO INCREASE NWD THRU ERN
TX INTO LOWER MS VALLEY TODAY IN ADVANCE OF THE COLD FRONT. ACTIVE
THUNDERSTORMS INCLUDING SUPERCELLS CONTINUE TO DEVELOP WELL IN
ADVANCE OF THE COLD FRONT IN THE ZONE OF FAVORABLE SHEAR AND
INSTABILITY.

...LOWER MS VALLEY...

BASED ON GREATER INSTABILITY THAN EARLIER EXPECTED A SMALL AREA OF
LA AND MS HAS BEEN UPGRADED TO A MDT RISK.

VERY STRONG SHEAR PROFILES EXPECTED TO REMAIN IN PLACE MUCH OF LOWER
MS VALLEY THRU THE DAY...SUPPORTIVE OF ORGANIZED THUNDERSTORMS
INCLUDING POTENTIAL TORNADIC SUPERCELLS. WARM SECTOR AIR MASS WILL
SPREAD NWD THRU ERN AR/MS AS 50-60KT SLY LLJ SHIFTS SLOWLY EWD FROM
LA/AR INTO MS/WRN TN BY THIS EVENING. DEWPOINTS RISING INTO LOW/MID
60S THRU LA INTO SRN HALF OF MS...WILL LEAD TO MLCAPES FROM
1000-1500 J/KG. THIS IS SUPPORTED BY THE 12Z LCH SOUNDING
CHARACTERIZED BY STEEP MID LEVEL LAPSE RATES AND MLCAPE IN EXCESS OF
1500 J/KG. LESSER INSTABILITY FURTHER N IN WARM SECTOR SUCH THAT
MUCH OF SEVERE THREAT WILL BE MAINLY S OF A CENTRAL AR/NRN MS LINE.

ONGOING STRONG/SEVERE THUNDERSTORMS FROM AR SWWD INTO ERN TX/NWRN LA
WILL SPREAD EWD WITH INCREASING THREAT OF TORNADIC SUPERCELLS...
PARTICULARLY NRN LA/FAR SRN AR INTO W CENTRAL MS WHERE STRONG
TORNADOES ARE POSSIBLE BY THIS AFTERNOON. THUNDERSTORMS WILL TEND
TO DEVELOP INTO MORE OF A LINE LATER THIS AFTERNOON AS THEY MOVE EWD
ACROSS LOWER MS VALLEY. PRIMARY THREAT WITH A LINEAR MODE WILL BE
DAMAGING WINDS AND HAIL. INTENSITY SHOULD GRADUALLY DIMINISH AS
STORMS BEGIN TO OUTRUN FAVORABLE LOW LEVEL INSTABILITY TN VALLEY SWD
THIS EVENING. HOWEVER SEVERE THREAT WILL LIKELY CONTINUE AFTER DARK
ACROSS PARTS OF MS.

..HALES.. 12/09/2008

[somethingfunny]

The National Weather Service will survey the damage in Collin and Grayson Counties to determine if in fact a tornado has touched down.

I can almost guarantee you the one here in Grayson County was a tornado.

The worst ended up skipping through Southmayd and went northeast into southern Denison and across the southeast side of the city. Damage is quite severe out that way....

http://www.kxii.com/home/headlines/35787304.html#

[Ed Mahmoud]

Monday severe near Louisiana?

Not sure the quality of moisture return...

40 knot low level jet off the Gulf and turning with height between 850 mb and 500 mb, with some suggestion of diffluent flow approaching Louisiana from Texas.




Looks like 850 mb and 700 mb RH are high enough that the cap probably isn't overwhelming

GFS is a less amplified, and a bit slower, Canadian seems to be between the two.

SPC not impressed.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0348 AM CST THU DEC 04 2008

VALID 071200Z - 121200Z

...DISCUSSION...
GFS AND ECMWF IN DECENT AGREEMENT THROUGH DAY 5 /MON. 12-8/...BUT
DIFFERENCES INCREASE SUBSTANTIALLY FROM THE START OF DAY 6 ONWARD
SUCH THAT PREDICTABILITY IS TOO LOW TO WARRANT ANY DEPICTION OF
POTENTIAL SEVERE THREATS.

IN THE MEAN TIME...BOTH MODELS FORECAST A SLOW EWD PROGRESSION OF
THE ERN U.S. UPPER TROUGH...WITH THIS FEATURE EXPECTED TO MOVE OFF
THE ATLANTIC DAY 5. MEANWHILE...A SECOND TROUGH IS PROGGED TO DIG
SEWD ACROSS THE ROCKIES...MAINTAINING LONG-WAVE TROUGHING OVER THE
CONUS. AS THE WRN TROUGH DIGS RAPIDLY SEWD TOWARD THE SRN
PLAINS...CYCLOGENESIS IS FORECAST OVER THE S CENTRAL CONUS.
RESULTING NWD RETURN OF MOISTURE COULD ALLOW AMPLE DESTABILIZATION
TO SUPPORT CONVECTIVE DEVELOPMENT DURING THE SECOND HALF OF DAY
5...BUT ATTM EXPECT THAT DESTABILIZATION WOULD BE INSUFFICIENT FOR A
SIGNIFICANT SEVERE EVENT.

Timing a day too fast, but again it seems using the Euro to spot a strong 850 mb jet being crossed at an angle by strong 500 mb flow ahead of a trough is a pretty easy way to detect potential severe weather events like the one of last night in Texas and today in Louisiana, Mississippi and Alabama.

[Bunkertor]

WFUS56 KLOX 150920
TORLOX
CAC079-083-151015-
/O.NEW.KLOX.TO.W.0004.081215T0920Z-081215T1015Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE OXNARD CA
120 AM PST MON DEC 15 2008

THE NATIONAL WEATHER SERVICE IN OXNARD HAS ISSUED A

* TORNADO WARNING FOR...
EXTREME SOUTH CENTRAL SAN LUIS OBISPO COUNTY IN SOUTHWEST
CALIFORNIA...
NORTHWESTERN SANTA BARBARA COUNTY IN SOUTHWEST CALIFORNIA...
THIS INCLUDES THE CITY OF SANTA MARIA...

* UNTIL 215 AM PST

* AT 112 AM PST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM 10 MILES WEST SOUTHWEST OF SANTA MARIA...MOVING
TO THE EAST NORTHEAST AT 30 MPH. THE THUNDERSTORM WAS JUST OFF THE
COAST AND RADAR SHOWED SIGNIFICANT ROTATION WITH THIS STORM.
WATERSPOUTS ARE LIKELY WITH THIS COULD COME ASHORE AS WEAK
TORNADOES.

* THE SEVERE STORM AND TORNADO WILL BE NEAR...
SANTA MARIA AND NIPOMO BY 140 AM PST...

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING
DIME SIZE HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.


SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
149 AM PST MON DEC 15 2008

CAC079-083-151015-
/O.CON.KLOX.TO.W.0004.000000T0000Z-081215T1015Z/
SANTA BARBARA CA-SAN LUIS OBISPO CA-
150 AM PST MON DEC 15 2008

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 215 AM PST FOR EXTREME
SOUTH CENTRAL SAN LUIS OBISPO AND NORTHWESTERN SANTA BARBARA
COUNTIES...

AT 141 AM PST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF VERY STRONG STORMS ACROSS NORTHWESTERN SANTA BARBARA
COUNTY NEAR SANTA MARIA. WHILE ROTATION ASSOCIATED WITH THE STRONGEST
STORM HAS WEAKENED...THE POTENTIAL REMAINS FOR DAMAGING WINDS AND WEAK
TORNADOES. DIME SIZED HAIL IS ALSO POSSIBLE. THESE STORMS WERE MOVING
EAST AT 25 MPH.