Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 270230
SWOMCD
SPC MCD 270229
TXZ000-270400-

MESOSCALE DISCUSSION 0475
NWS STORM PREDICTION CENTER NORMAN OK
0929 PM CDT SUN APR 26 2015

AREAS AFFECTED...N CNTRL TEXAS

CONCERNING...TORNADO WATCH 121...

VALID 270229Z - 270400Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 121 CONTINUES.

SUMMARY...THE RISK FOR STRONG...DAMAGING WIND GUSTS IS EXPECTED TO
INCREASE WITH AN EVOLVING CLUSTER OF STORMS AS IT SPREADS ACROSS THE
DALLAS/FORT WORTH METROPLEX BETWEEN 03-05Z.  A DISCRETE SUPERCELL
MAY ALSO PERSIST WITH A CONTINUING RISK FOR TORNADOES...MAINLY
SOUTHWEST TO JUST SOUTH OF THE METROPLEX.

DISCUSSION...INTENSE CONVECTIVE DEVELOPMENT...INCLUDING AN ISOLATED
DISCRETE SUPERCELL OR TWO...PERSISTS TO THE WEST AND SOUTHWEST OF
THE DALLAS/FORT WORTH METROPLEX...AIDED BY FAVORABLE LARGE-SCALE
FORCING FOR ASCENT DOWNSTREAM OF A CLOSE MID-LEVEL LOW SLOWLY
SHIFTING EAST OF THE SOUTHERN ROCKIES.  LOW-LEVEL CONVERGENCE
APPEARS TO BE STRONG WITHIN A ZONE EXTENDING FROM THE ONGOING
CONVECTION EASTWARD ACROSS MUCH OF THE METROPLEX.  THIS MAY PROVIDE
SUPPORT FOR FURTHER UPSCALE CONVECTIVE GROWTH...AND THE FOCUS FOR
EASTWARD ACCELERATION AS THIS OCCURS.

GIVEN THE SIZABLE LOWER/MID TROPOSPHERIC TEMPERATURE DEW POINT
SPREADS EVIDENT IN THE 27/00Z FTW RAOB...HEAVY PRECIPITATION LOADING
AND EVAPORATIVE COOLING PROBABLY WILL CONTRIBUTE TO INCREASING
POTENTIAL FOR STRONG...DAMAGING WIND GUSTS.  THIS WILL BE ENHANCED
FURTHER BY THE STRONG VERTICAL SHEAR PRESENT....ASSOCIATED WITH NEAR
SURFACE EASTERLIES VEERING TO STRONG WESTERLIES AT MID/UPPER LEVELS.


IT IS UNCLEAR HOW MUCH LONGER THE DISCRETE SUPERCELL...NOW EAST OF
STEPHENVILLE...WILL PERSIST.  BUT IT CURRENTLY SEEMS LIKELY TO
GENERALLY PASS JUST TO THE SOUTH OF THE BULK OF THE
METROPLEX...ALONG THE LEADING EDGE OF THE DEEPER BOUNDARY LAYER
MOISTURE.

..KERR.. 04/27/2015

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

ATTN...WFO...FWD...

LAT...LON   33059769 33209714 33189613 32739574 32299589 32119652
            32059728 32339787 32719792 33059769



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