434
ACUS11 KWNS 180816
SWOMCD
SPC MCD 180815
ARZ000-OKZ000-180915-
MESOSCALE DISCUSSION 0851
NWS STORM PREDICTION CENTER NORMAN OK
0315 AM CDT SUN MAY 18 2025
AREAS AFFECTED...CENTRAL/EASTERN OKLAHOMA INTO WESTERN ARKANSAS
CONCERNING...SEVERE THUNDERSTORM WATCH 283...
VALID 180815Z - 180915Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 283
CONTINUES.
SUMMARY...ORGANIZED CLUSTER OF THUNDERSTORMS WILL CONTINUE TO POSE A
THREAT OF LARGE HAIL AND DAMAGING WINDS. AN EXTENSION IN TIME FOR
SEVERE THUNDERSTORM WATCH #283 WILL BE NEEDED.
DISCUSSION...A LINEAR MCS HAS ORGANIZED ACROSS CENTRAL OKLAHOMA THIS
MORNING AND WILL CONTINUE TO MOVE EAST/EAST-SOUTHEAST ALONG AN
INSTABILITY AXIS STRETCHING FROM NORTHWEST OKLAHOMA INTO SOUTHEAST
ARKANSAS. TO THE SOUTH OF THIS AXIS, RICH LOW-LEVEL MOISTURE COUPLES
WITH STEEP MID-LEVEL LAPSE RATES TO YIELD MUCAPE IN EXCESS OF 3500
J/KG. EFFECTIVE-LAYER SHEAR IS GENERALLY GREATER THAN 45-50 KNOTS,
WHICH IS MORE THAN SUFFICIENT TO MAINTAIN UPDRAFT ORGANIZATION. IN
FACT, RECENTLY THE OKLAHOMA MESONET STATION IN OKMULGEE, OK,
MEASURED A 60 MPH WIND GUST.
THIS MCS IS CURRENTLY CONTAINED WITHIN SEVERE THUNDERSTORM WATCH
#283, WHICH IS SET TO EXPIRE AT THE TOP OF THE HOUR (0900 UTC / 0400
AM CT). GIVEN THAT THE OVERALL ENVIRONMENT REMAINS SUPPORTIVE OF
ORGANIZED SEVERE WEATHER, AND THE EXISTING ORGANIZED MCS, WITHIN
THIS ENVIRONMENT, THE THREAT FOR LARGE HAIL AND DAMAGING WINDS WILL
LIKELY CONTINUE PAST THE ORIGINAL EXPIRATION TIME OF 0900 UTC (4 AM
CT). AS SUCH, A LOCAL EXTENSION IN SPACE AND TIME (TO 1200 UTC / 7
AM CT) HAS BEEN COORDINATED WITH WFO TSA.
..MARSH.. 05/18/2025
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...TSA...OUN...
LAT...LON 35179666 36179574 36109350 34649473 35179666
MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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