Saturday, April 21, 2007

MESO: Mesoscale Discussion 0527

ACUS11 KWNS 212257
SWOMCD
SPC MCD 212257
SDZ000-NEZ000-COZ000-220100-

MESOSCALE DISCUSSION 0527
NWS STORM PREDICTION CENTER NORMAN OK
0557 PM CDT SAT APR 21 2007

AREAS AFFECTED...EXTREME NERN CO...SWRN AND CENTRAL NEB

CONCERNING...TORNADO WATCH 154...

VALID 212257Z - 220100Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 154 CONTINUES.

A FEW STRONG SUPERCELLS HAVE BEEN MOVING THRU CHERRY COUNTY...AND
ACROSS NERN CO OVER THE PAST FEW HOURS. THE ACTIVITY OVER ERN
CHERRY COUNTY IS BEING ENHANCED BY A CONVECTIVE OUTFLOW BOUNDARY AS
WELL AS VERY STRONG SFC/LOW LEVEL FLOW. THE ACTIVITY IS MOVING NEWD
INTO INCREASING 0-1 KM HELICITY WHERE VALUES ARE 150-200 M2/S2 WHICH
WILL ENHANCE STORM RELATIVE FLOW INTO THE SUPERCELL MOVING NEWD OVER
ERN CHERRY COUNTY.

OVERALL...THE ENVIRONMENT REMAINS VERY FAVORABLE FOR SUSTAINING
UPDRAFTS/SUPERCELLS ESPECIALLY NEAR THE BOUNDARIES AS MLCAPE IS VERY
UNSTABLE WITH VALUES BETWEEN 1500-2500 J/KG AND DEEP LAYER SHEAR OF
45-55 KT. GIVEN THE CURRENT RADAR...MAIN THREAT AREAS WILL BE FROM
ERN CHERRY COUNTY NEWD INTO BROWN AND KEYA PAHA NEB...THEN TRIPP AND
GREGORY COUNTIES IN SD IN WW 155. ALSO..THE LARGE SUPERCELL OVER
SEDGWICK AND PHILLIPS COUNTIES IN CO SHOULD MOVE INTO KEITH AND
PERKINS COUNTIES IN NEB DURING THE NEXT SEVERAL HOURS.

.MCCARTHY.. 04/21/2007

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

ATTN...WFO...FSD...GID...LBF...UNR...GLD...BOU...CYS...

40430265 40900265 41080260 41560263 42000265 42040200
42670205 42990195 42940015 42999932 42979843 42709832
42089830 41739832 41709879 41329878 41099880 41019922
40699947 40419965 40380003 40420045 40390129 40300204
40400211 40430261

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