Mesoscale Discussion 55

Issued

Jan 23, 2012, 1:25 AM CST (07:25 UTC)

Expired

Jan 23, 2012, 3:30 AM CST

In force

2 hr

Issued by

the Storm Prediction Center

The Columbus AFB radar (KGWX), 106 km from the middle of the area, began a volume at 07:25 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

• Severe Thunderstorm Watch 10Jan 23, 1:50 AM CST
• Tornado Watch 11Jan 23, 2:45 AM CST

481 
ACUS11 KWNS 230726
SWOMCD
SPC MCD 230725
TNZ000-KYZ000-GAZ000-ALZ000-MSZ000-LAZ000-230930-

MESOSCALE DISCUSSION 0055
NWS STORM PREDICTION CENTER NORMAN OK
0125 AM CST MON JAN 23 2012

AREAS AFFECTED...PORTIONS MIDDLE-ERN TN...MS EXCEPT COASTAL AND NWRN
PORTIONS...WRN/CENTRAL/NRN AL...SMALL PART OF NERN LA...EXTREME NWRN
GA.

CONCERNING...TORNADO WATCH 7...

VALID 230725Z - 230930Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 7 CONTINUES.

WW MAY BE CLEARED FROM W-E BEHIND PRIMARY SQUALL/CONFLUENCE LINE
OUTLINED BELOW.  OTHERWISE CONTINUE WW.  FARTHER E...ADDITIONAL WW
MAY BE REQUIRED DURING NEXT 1-2 HOURS OVER PORTIONS MID-ERN TN AND
AL.

VERY FAVORABLE SUPERIMPOSITION OF BUOYANCY AND VERTICAL SHEAR WILL
CONTINUE NEAR AND SW OF WARM FRONT...ANALYZED AT 07Z NEAR LINE FROM
TOI...BHM...50 SW BNA WHERE IT WAS BEING OVERTAKEN BY MAIN
CONVECTIVE BAND.  LATTER CONVECTION SHOULD CONTINUE MOVING ENEWD
ABOUT 45 KT ACROSS MID TN...AND ABOUT 35 KT FROM NERN LA INTO WRN
MS...POSING THREAT FOR DAMAGING GUSTS AND OCNL/BRIEF QLCS TORNADOES.
 VWP AND FCST SOUNDINGS SUGGEST EFFECTIVE SRH 300-600 J/KG AND
EFFECTIVE SHEAR MAGNITUDES 50-60 KT OVER MOST OF MS AND WRN/NRN
AL...AMIDST MLCAPE VALUES 500-1200 J/KG.  GIVEN SUCH
CONDITIONS...POTENTIAL FOR SIGNIFICANT TORNADOES STILL EXISTS AS
WELL...PRIMARILY WITH SUPERCELLS IN WARM SECTOR...AND THOSE
INTERACTING WITH WARM FRONTAL ZONE RICHLY LADEN WITH LOW-LEVEL
VORTICITY.  SUPERCELLS MAY BE EITHER SEMI-DISCRETE...OR EMBEDDED IN
SHORT LINE SEGMENTS OF CONVECTION ASSOCIATED WITH SFC-900 MB
CONFLUENCE LINES THAT ARE EVIDENT IN OBSERVED LOW-LEVEL WIND DATA
OVER CENTRAL/ERN MS AND NERN MS.

OVER NRN PORTIONS WW...MAIN TSTM BAND WILL OVERTAKE MORE
SLOWLY-MOVING SFC WARM FRONT FROM NW-SE...EFFECTIVELY SHUNTING NRN
BOUND OF OPTIMAL BOUNDARY-LAYER AIR MASS SWD OUT OF ERN TN WITH
TIME.  NONETHELESS...WARM FRONT IS SHALLOW...AND HIGH-MOMENTUM AIR
MAY PENETRATE TO SFC WELL TO ITS NE...ESPECIALLY OVER HIGHER
ELEVATIONS.  THEREFORE...PRIND DAMAGING-WIND POTENTIAL MAY EXTEND
ACROSS MOST OF ERN TN AND NERN AL.  INVOF SRN PORTIONS WW...SVR TSTM
POTENTIAL WILL DIMINISH WITH SWD EXTENT TOWARD GULF COAST...AS
STRONGEST ISALLOBARIC FORCING SHIFTS POLEWARD AWAY FROM AREA AND
CONVERGENCE REMAINS WEAK.

..EDWARDS.. 01/23/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MRX...JKL...FFC...LMK...OHX...BMX...HUN...MOB...
MEG...JAN...

LAT...LON   36638619 36588331 34878496 33578579 32268672 32138751
            31598891 31369104 32179161 34468873 35478742 36128708
            36598670 36638619

Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Alabama, 2012Every mesoscale discussion in 2012

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.