[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 200457
SWOMCD
SPC MCD 200456
OHZ000-WVZ000-KYZ000-TNZ000-INZ000-ALZ000-MSZ000-200630-

MESOSCALE DISCUSSION 0485
NWS STORM PREDICTION CENTER NORMAN OK
1156 PM CDT TUE APR 19 2011

AREAS AFFECTED...SWRN/CNTRL OH...SERN IND...WRN KY...WRN TN...NRN MS

CONCERNING...TORNADO WATCH 159...160...

VALID 200456Z - 200630Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 159...160...CONTINUES.

A NEW WW MAY BE NEEDED EAST OF THE ONGOING CONVECTION ACROSS
PORTIONS OF SRN OH...WRN WV...ERN KY...CNTRL/ERN TN...AND NRN AL.

AN EXTENSIVE QLCS STRETCHING FROM WRN OH AND SERN IND SWD INTO NRN
MS CONTINUES PROGRESSING EWD. WELL-DEFINED BOWING LINE SEGMENTS OVER
WRN KY AND FAR WRN TN WILL CONTINUE TO RAPIDLY MOVE EWD AT 50 KT.
CONTINUED FORWARD PROPAGATION IS ANTICIPATED...BRING THE SEVERE
THREAT INTO PORTIONS OF CNTRL KY AND ACROSS WRN TN/NRN MS DURING THE
NEXT FEW HOURS...AS DEEP-LAYER SHEAR VECTORS CONTINUE TO MAINTAIN A
COMPONENT ORTHOGONAL TO THE LEADING CONVECTIVE LINE. WIDESPREAD DMGG
WINDS WILL REMAIN A CONCERN...ESPECIALLY WITH THE BETTER-DEFINED
BOWING LINE SEGMENTS. FARTHER NORTH INTO SWRN AND CNTRL
OH...CONVECTIVE OUTFLOW IS BEGINNING TO ACCELERATE AHEAD OF THE
DEEPER CONVECTION...SUGGESTING THAT ASCENT WILL BECOME INCREASINGLY
SLOPED /AS OPPOSED TO UPRIGHT/ WITH TIME AS THE LINE APPROACHES
CNTRL AND S-CNTRL OH. HOWEVER...IN THESE AREAS...MODERATE
INSTABILITY WITHIN THE WARM SECTOR SHOULD COMPENSATE...YIELDING A
CONTINUED DMGG WIND POTENTIAL /ALBEIT NOT AS HIGH AS FARTHER SOUTH/.
GIVEN THE OVERALL CONVECTIVE MODE BEING LINEAR...THE PRIMARY SEVERE
THREAT WILL CONTINUE TO EVOLVE TOWARD DMGG WINDS. HOWEVER...A THREAT
FOR ISOLATED TORNADOES PERSISTS GIVEN EFFECTIVE SRH VALUES AOA 300
M2/S2 DUE TO A STRONG LOW-LEVEL JET. THIS IS ESPECIALLY THE CASE
INTO NRN MS...WHERE CONVECTION REMAINS SOMEWHAT MORE DISCRETE.

WHILE INSTABILITY EAST OF WW159 AND WW160 IS SOMEWHAT LESS THAN
UPSTREAM...THE WELL-DEFINED COLD POOL CIRCULATIONS AND STRONG
DEEP-LAYER WIND SHEAR COULD CONTINUE TO MAINTAIN A THREAT FOR DMGG
WINDS. THUS...A NEW WATCH MAY BE NEEDED DOWNSTREAM OF THE ONGOING
CONVECTION NEAR OR JUST AFTER 06Z.

..COHEN.. 04/20/2011

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

ATTN...WFO...RLX...MRX...JKL...ILN...LMK...OHX...IND...BMX...
HUN...PAH...MEG...JAN...

LAT...LON   33979094 35068969 36558863 37128728 37758621 39388520
            40228354 39908239 38188239 36048451 34438651 33578822
            33429025 33979094


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