[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 262317
SWOMCD
SPC MCD 262317
TNZ000-KYZ000-ILZ000-MSZ000-MOZ000-ARZ000-TXZ000-OKZ000-KSZ000-270115-

MESOSCALE DISCUSSION 0601
NWS STORM PREDICTION CENTER NORMAN OK
0617 PM CDT TUE APR 26 2011

AREAS AFFECTED...AR...PORTIONS ERN OK...SERN KS...SRN MO...EXTREME
SRN IL...WRN KY...NWRN MS...WRN TN.

CONCERNING...TORNADO WATCH 215...217...221...

VALID 262317Z - 270115Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH
215...217...221...CONTINUES.

SVR CONVECTION...INCLUDING SEVERAL POTENTIALLY TORNADIC
SUPERCELLS...CONTINUES TO INCREASE IN COVERAGE ACROSS DISCUSSION
AREA FROM ERN OK TO MS RIVER NEAR MEM.

WARM-SECTOR ENVIRONMENT WILL REMAIN FAVORABLE FOR TORNADIC
SUPERCELLS.  IN FACT...PRE-STORM LOW-LEVEL SHEAR PROFILES ARE
EXPECTED TO BECOME VERY FAVORABLE FOR BOTH SIGNIFICANT/DESTRUCTIVE
TORNADOES AND WIND DAMAGE DURING NEXT 3-4 HOURS AS LLJ STRENGTHENS
JUST ABOVE SFC...SUBSTANTIALLY BOOSTING LOW-LEVEL SHEAR AND SRH.
LARGE/DESTRUCTIVE HAIL ALSO IS LIKELY FROM INDIVIDUAL SUPERCELLS.

SFC MESOANALYSIS SHOWS LOW OVER ERN OK JUST W FSM...COLD FRONT SWWD
ACROSS LAMAR COUNTY TX...QUASISTATIONARY FRONTAL ZONE CURVING NEWD
OVER NWRN AND EXTREME N-CENTRAL AR.  FRONT BECOMES COLD FRONT AGAIN
FROM NERN AR NEWD ACROSS SERN MO.  THOSE FRONTAL ZONES WILL ACT AS
NRN/WRN BOUNDS FOR SFC-BASED EFFECTIVE INFLOW PARCELS...ALTHOUGH
TSTMS TO THEIR N AND W ACROSS SERN KS/NERN OK/SWRN MO REGION WILL BE
IN FAVORABLE ELEVATED SHEAR AND BUOYANCY FOR LARGE HAIL.  IN REGIME
OF STG LOW-LEVEL WAA AND SHEAR SE OF FRONTAL ZONE...OUTFLOW
BOUNDARIES PRODUCED BY ONGOING CONVECTION OVER AR MAY MIX/ADVECT
AWAY RATHER QUICKLY...BUT ALSO CAN SUPPLY ADDITIONAL LOW-LEVEL
VORTICITY/SHEAR ABOVE ALREADY STRONG ENVIRONMENTAL VALUES.  MODIFIED
RAOBS AND RUC SOUNDINGS INDICATE MLCAPE RANGING FROM 3000 J/KG OVER
CONVECTIVELY UNPERTURBED AIR MASS OF CENTRAL/SRN AR...NARROWING TO
CORRIDOR OF 1500-2500 J/KG MLCAPE NEWD TOWARD LOWEST OH VALLEY.
EFFECTIVE SHEAR MAGNITUDES 50-60 KT AND 0-1 KM SRH 150-300 J/KG ARE
COMMON...WITH SRH FCST TO INCREASE SUBSTANTIALLY AFTER 00Z BENEATH
LLJ.

..EDWARDS.. 04/26/2011

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

ATTN...WFO...LMK...OHX...PAH...MEG...JAN...LZK...SGF...SHV...
TSA...ICT...

LAT...LON   37898694 36488706 34408942 33139239 33659476 34139540
            35219500 35869529 36289594 36389649 37189557 37519446
            37409369 36819322 36689204 37029054 37698896 37728701
            37898694


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