####018003503#### AWUS01 KWNH 150722 FFGMPD TNZ000-KYZ000-ILZ000-MOZ000-ARZ000-151315- Mesoscale Precipitation Discussion 0037 NWS Weather Prediction Center College Park MD 220 AM EST Sat Feb 15 2025 Areas affected...northeastern AR across MS Valley into KY and TN Concerning...Heavy rainfall...Flash flooding possible Valid 150717Z - 151315Z SUMMARY...The threat for flash flooding will steadily increase over the next 3-6 hours from northeastern AR, across the MS Valley and into KY and TN. Training and repeating rounds of rain will produce peak hourly rainfall of 0.5 to 1.5 inches and 6 hour totals of 1 to 2 inches, locally as high as 3 inches. DISCUSSION...Scattered showers and elevated thunderstorms were observed to be increasing in coverage over portions of the lower and middle MS Valleys in association with strong low level warm air advection. 850 mb winds were from the S to SW, peaking around 70 kt in southern MO (per VAD wind data). Layered PW imagery showed the rapid northward return of moisture from the eastern half of TX into the lower MS Valley (surface to 700 mb layers), allowing for the swift development of MUCAPE from west to east as dewpoints in the lower layers of the troposphere increase, allowing parcels to make use of relatively steep 700-500 mb lapse rates (6-7 C/km). Regional radar imagery at 07Z showed a persistent region of elevated convection from northeastern AR into northwestern TN, co-located with an axis of moisture flux convergence located at the leading edge of low level moisture return. Alignment of this axis and the mean steering flow from the WSW has caused training and repeating rounds of heavy rain to affect portions of northeastern AR into far northwestern TN. Local Wunderground rainfall network observations have shown 0.3 to 0.6 inches of rain within 30 minutes and one report as high as 0.7 inches in 30 minutes, just south of the MO Bootheel from ~06Z. Expectations are for continued low level warm air advection to maintain the trend of increasing MUCAPE values toward the east, supporting elevated thunderstorms into central KY/TN later this morning. RAP forecasts indicate little latitudinal movement of the elevated zone of low level convergence over the next several hours and additional upstream development is anticipated over AR in the 12-15Z window as forcing for ascent increases ahead of an approaching shortwave trough axis which extended from the central High Plains into the Desert Southwest at 07Z. Repeating rounds of showers and thunderstorms will continue through the morning with periodic episodes of training which will translate into locally high rainfall rates. Soil moisture across a large portion of the region is above average due to recent rainfall and/or snow melt. As a result, FFG values are low, with less than 2 inches in 3 hours along the KY/TN border and less than 2.5 inches in 3 hours closer to the MS River. While this MPD is tagged with flash flooding "possible", the threat is only expected to increase over the region during the daytime hours. Otto ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...JKL...LMK...LZK...MEG...MRX...OHX...PAH...SGF... ATTN...RFC...ABRFC...LMRFC...OHRFC...NWC... LAT...LON 37398765 37278539 36858434 36188435 35808534 35518752 35158996 34769206 35459269 36329152 37068991 ####018000753#### PENA01 KWNH 151200 @UHPISF000CN MPDSUM@V2.0@0101700060@12150225@@0NMCGPHMPDp@!' `' ` @ & B7)p&PNAM02@@Iׁ~|zz||||}~}~}}}}~}~}}~}}~}}|}}~~@@׀@@׀@@!0037 @@d&MESOSCALE DISCUSSION SUMMARY GRAPHIC @@d& OF ALL VALID MESOSCALE DISCUSSIONS AT @@d& TIME OF PRODUCT CREATION:@@d& ISSUED 02/15/2025 0722Z @@ dNOAA/NWS/NCEP@@d WEATHER PREDICTION CENTER @@d FOR COLOR VERSION SEE: @@d WWW.WPC.NCEP.NOAA.GOV @