Tornado Outbreak Likely On Christmas Eve Into Christmas Day

[Derecho 50]

Unfortunately parameters are still in place for the potential for a major severe weather threat for the Deep South Tuesday into Tuesday night. If you are reading this, I am not worried about you and your family being aware of the threat, but be sure and pass this on to your friends, neighbors, and relatives. We have a much harder time reaching the masses at Christmas time, but this is something everybody needs know. This isn’t to alarm anyone, but simply to let you know you need to be close to a source of severe weather information.

THE SETUP: A deep surface low will run from near Shreveport to Nashville Christmas Day. This keeps Alabama in the warm sector of the storm system, and all models show sufficient instability and shear/helicity for severe weather… below is the projected instability at 6pm CST Tuesday. The green is where lifted index goes below zero, or where there is surface based instability.

Bulk shear values remain impressive southeast of the surface low…

Below is the SPC “Day Three†convective outlook…

The “hatched area†below is where significant severe weather is possible, roughly from Tuscaloosa southwest to near Lake Charles. SPC defines significant severe weather as F2 or greater tornadoes, damaging winds with speeds greater than 65 knots, or large hail 2″ or greater in diameter.

THREATS: We will have the dual threat of severe storms with damaging winds, and tornadoes with this system. If discrete cells can form ahead of the main squall line, some of them could rotate and produce a tornado. A strong tornado is possible considering the dynamics.

PLACEMENT: The greatest risk of severe weather in Alabama will be along and south of U.S. 278… Hamilton to Cullman to Gadsden… but the latest model data suggests a few strong to severe storms are possible up to the Tennessee border, but the limited instability there suggests the risk could be smaller. Bottom line is that all of the area will need to be ready for this.

TIMING: Keep in mind showers are possible as early as tonight as moisture begins to return and a warm front organizes to the south. We will have potential for showers tomorrow and tomorrow night as well, but as the warm front lifts north of here and we get into the unstable air, the primary risk of severe weather will come from 2:00 p.m. Tuesday through 2:00 a.m. Wednesday.

CALL TO ACTION: This is a very challenging event due to so many people traveling. Bottom line is this… everybody in the area needs to be sure they have a good way of hearing severe weather and tornado warnings, and that should NEVER be an outdoor siren. Those things are good only for reaching a handful of people outdoors. Have a good, working NOAA Weather Radio receiver in your home, properly programmed, with fresh batteries in case power goes out. On top of that, if you have a smart phone, have a good warning app installed and running, and of course, properly programmed.

For iPhone, a great choice is MyWarn. For Android phones, iMap WeatherRadio is fantastic; there is also an iPhone version. You can watch our live streaming coverage on both, and you receive the warnings only if you are in a tornado warning polygon (remember, warnings are polygon based, not county based).

And, be sure you review your plan of action. If you live in a mobile home and you are in a tornado warning polygon, you have to leave and go to shelter. In site built homes, be in a small room (hall, closet, bathroom) on the lowest floor (basement if you have one), away from windows, and near the center of the house. Be sure everybody in your home, including visitors, understands this plan.

Credit goes to James Spann for the lengthy article above, but I'm able to answer any questions or address any concerns regarding the potential outbreak.

[AndreC 48]

fml. I'm right up in there if it comes.

[Klaa 4,872]

Aim for the green lady riding a broomstick.

Just got out of a snowstorm that knocked out power for a day and the cable broadband was down till recently. Charter, Meh! Unfortunately they are the only game in town for any broadband.

Fortunately, Oregon's power supply is a long-running joke, so Im well prepped with decent UPS, candles, water, and all those other essentals for brownouts and blackouts.

[Derecho 50]

An update guys -

A day 2 moderate risk has been issued, these are issued fairly rarely and most of my buddies in meteorology are calling it about a 80% chance of a significant tornado outbreak.

If you live in this area, PLEASE pay attention to the weather and take any warnings seriously, the environment is very capable of putting down multiple long track, strong/violent tornadoes.

If this forecast pans out, the loss of life is inevitable, I just hope everyone takes this seriously.

And the wording from the NWS -

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF LA...SCNTRL MS

AND WCNTRL AL...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN

PLAINS...LOWER MS VALLEY...TN VALLEY...ERN GULF COAST STATES AND SRN

APPALACHIAN MTNS...

...SIGNIFICANT SEVERE WEATHER EVENT SETTING UP FOR CHRISTMAS DAY FOR

PARTS OF THE GULF COAST STATES...

...LOWER MS VALLEY/GULF COAST STATES...

AN IMPRESSIVE UPPER-LEVEL SYSTEM IS FORECAST TO MOVE ACROSS THE SRN

PLAINS INTO THE LOWER MS VALLEY ON TUESDAY. A POWERFUL MID-LEVEL JET

IN THE BASE OF THE UPPER-LEVEL SYSTEM WILL TRANSLATE QUICKLY EWD

OVER A MOISTENING WARM SECTOR RESULTING IN THE POTENTIAL FOR A

SIGNIFICANT SEVERE WEATHER EVENT ACROSS PARTS OF THE LOWER MS VALLEY

AND CNTRL GULF COAST STATES. AS THE UPPER-LEVEL TROUGH APPROACHES

THE REGION...MODEL FORECASTS MOVE A BAND OF STRONG LARGE-SCALE

ASCENT QUICKLY EWD ACROSS CNTRL TX EARLY TUESDAY MORNING WHICH

COINCIDES WITH A MOISTENING BOUNDARY LAYER ACROSS MUCH OF THE TX

COASTAL PLAINS. IN RESPONSE...THUNDERSTORM DEVELOPMENT SHOULD BE

UNDERWAY AT DAYBREAK ON TUESDAY WITH A CLUSTER OF STRONG TO

POTENTIALLY SEVERE STORMS MOVING ENEWD FROM SE TX INTO THE LOWER MS

VALLEY AROUND MIDDAY.

FORECAST SOUNDINGS AT VICKSBURG AND JACKSON MS ON TUESDAY GRADUALLY

DEVELOP MODERATE INSTABILITY WITH SFC DEWPOINTS REACHING THE LOWER

TO MID 60S F. THIS COMBINED WITH STRENGTHENING DEEP LAYER SHEAR AS

0-6 KM SHEAR APPROACHES 60 KT BY EARLY AFTERNOON SHOULD BE FAVORABLE

FOR SUPERCELLS AND TORNADOES. 0-3 KM STORM RELATIVE HELICITIES OF

350 TO 400 M2/S2 SHOULD BE SUPPORTIVE OF STRONG TORNADOES WITH THE

GREATEST THREAT ALONG A CORRIDOR FROM NEAR LAKE CHARLES LA TUESDAY

MORNING ACROSS SCNTRL MS INTO WCNTRL AL BY TUESDAY EVENING.

INSTABILITY...MOISTURE AND SHEAR PROFILES SUGGEST THAT ANY MCS THAT

BECOMES WELL-ORGANIZED COULD CONTAIN A TORNADO THREAT FOR AN

EXTENDED PERIOD. FOR THIS REASON...LONG TRACK TORNADOES COULD OCCUR

WITH SUPERCELLS THAT REMAIN DISCRETE AND MOVE ALONG THE NRN EDGE OF

MODERATE INSTABILITY. IN ADDITION...WIND DAMAGE WILL BE LIKELY WITH

LINE-SEGMENTS THAT ORGANIZE ON THE LEADING EDGE OF THE MCS. A THREAT

FOR WIDESPREAD WIND DAMAGE MAY DEVELOP ACROSS THE REGION TUESDAY

WITH WIND GUSTS OVER 70 KT POSSIBLE WITH BOWING SEGMENTS EMBEDDED IN

THE LINE. IF A WELL-DEVELOPED AND FAST MOVING SQUALL-LINE

ORGANIZES...THEN THE WIND DAMAGE THREAT COULD BECOME SUBSTANTIAL.

THE THREAT FOR SEVERE STORMS SHOULD CONTINUE THROUGH MUCH OF THE

OVERNIGHT PERIOD REACHING THE SRN APPALACHIAN MTNS AND ERN GULF

COAST STATES LATE TUESDAY NIGHT.

Edited December 24, 2012 by Derecho

[Theflash 54]

ouch im so happy i dont live there now, im thankful im in south africa where there is no tornados /o/