MD 0437 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR CNTRL KS INTO NWRN OK
MESOSCALE DISCUSSION 0437
NWS STORM PREDICTION CENTER NORMAN OK
0150 PM CDT SUN APR 24 2016
AREAS AFFECTED...CNTRL KS INTO NWRN OK
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 241850Z - 242115Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...WIDELY SCATTERED CONVECTIVE INITIATION IS LIKELY DURING
THE 20-22Z PERIOD OVER KS AND ISOLATED CONVECTIVE INITIATION IS
PROBABLE DURING THE 22-01Z PERIOD FROM THE KS-OK BORDER REGION SWD
INTO OK. LARGE TO VERY LARGE HAIL WILL BE POSSIBLE WITH STRONGER
UPDRAFTS THAT DEVELOP INTO SUPERCELLS. A MODEST WEAK-TORNADO RISK
WILL BE CONFINED TO THE EARLY EVENING /23-02Z/ WHEN LOW-LEVEL SHEAR
STRENGTHENS AND TEMP/DEWPOINT SPREADS LOWER.
DISCUSSION...18Z SURFACE ANALYSIS PLACES A SHARPENING
DRYLINE/CONFLUENT LOW-LEVEL FLOW FROM 25 MI W RSL SWD ALONG THE
TX-OK BORDER. DEWPOINTS HAVE RISEN INTO THE 59-62 DEG F RANGE
DURING THE PAST FEW HOURS IN W-CNTRL OK PER OK MESONET OBSERVATIONS.
STRONG HEATING COUPLED WITH GRADUAL MOISTENING ARE CONTRIBUTING TO
MODERATE BUOYANCY. WATER VAPOR IMAGERY SHOWS A WELL-DEFINED
MID-LEVEL VORTICITY MAXIMUM ROTATING THROUGH THE BASE OF
LARGER-SCALE TROUGH ACROSS W-CNTRL KS EARLY THIS AFTERNOON. THIS
FEATURE WILL MOVE INTO CNTRL AND ERN PORTIONS OF KS/S-CNTRL NEB BY
LATE AFTERNOON. THE TRAILING PORTION OF THIS FEATURE AND IMPLIED
WEAK ASCENT WILL SPREAD ACROSS NWRN OK DURING THE LATE
AFTERNOON/EARLY EVENING.
SURFACE OBSERVATIONS DURING THE PAST FEW HOURS IMPLY THE SPC
RAP-BASED OBJECTIVE ANALYSES ARE SUFFERING FROM THE RAP OVER-MIXING
DRY BIAS YIELDING AN UNDER-REPRESENTATION OF LOW-LEVEL MOISTURE.
WRF-BASED GUIDANCE /PARTICULARLY THE NAM/ APPEARS TO EXHIBIT A MORE
REASONABLE SOLUTION REGARDING MOISTURE/MIXING AND SUBSEQUENT CAP
EROSION AND CONVECTIVE INITIATION PROCESSES.
CONVECTIVE INITIATION WILL LIKELY OCCUR FIRST ACROSS CNTRL KS ALONG
THE DRYLINE AND GRADUALLY INCLUDE AREAS FARTHER S ALONG THE KS/OK
BORDER BY LATE THIS AFTERNOON AND INTO NWRN OK DURING THE EARLY
EVENING HOURS. DEEP SHEAR VECTORS ORIENTED ORTHOGONAL TO THE
SURFACE BOUNDARIES COUPLED WITH EFFECTIVE SHEAR MAGNITUDES OF 40-50
KT WILL FAVOR DISCRETE SUPERCELL MODE WITH THE STRONGER/SUSTAINED
UPDRAFTS. LOW-LEVEL SHEAR /I.E. SRH/ RISES INTO THE 100-250 M2/S2
RANGE DURING THE 23-02Z PERIOD AND WILL GENERALLY COINCIDE WITH SOME
WEAK TORNADO POTENTIAL WITH ANY STRONGER/SUSTAINED SUPERCELL.
STRENGTHENING CONVECTIVE INHIBITION AFTER 01-02Z WILL TEND TO
RESTRICT STORM INTENSITY/COVERAGE THIS EVENING AS MOST OF THE
ACTIVITY DIMINISHES.
..SMITH/CORFIDI.. 04/24/2016
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...TOP...ICT...OUN...GID...DDC...
LAT...LON 36219954 39369873 39799813 39829708 39409668 35889771
35739814 35739923 36219954
from SPC Mesoscale Discussions http://1.usa.gov/1Gqfm5r
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