Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Mar 03 2023 04:36:54 AWUS01 KWNH 030436 FFGMPD TNZ000-KYZ000-INZ000-ILZ000-MSZ000-MOZ000-ARZ000-031035- Mesoscale Precipitation Discussion 0085 NWS Weather Prediction Center College Park MD 1135 PM EST Thu Mar 02 2023 Areas affected...Portions of the Lower MS Valley and Lower OH Valley Concerning...Heavy rainfall...Flash flooding likely Valid 030435Z - 031035Z SUMMARY...Widespread and locally significant flash flooding is expected overnight across portions of the Lower MS Valley and potentially reaching into parts of the Lower OH Valley toward dawn as persistent areas of heavy showers and thunderstorms yield excessive rainfall totals. DISCUSSION...The latest GOES-16 Airmass RGB satellite imagery shows a powerful upper-level trough and associated closed low continuing to cross the southern Plains while producing widespread strong to severe thunderstorms and locally very heavy rainfall. Radar imagery shows the more concentrated heavy rainfall aligning itself across much of central to northeast AR while steadily expanding off to the northeast with time. This particular corridor is experiencing ongoing rainfall rates of as much as 1 to 3 inches/hour as proximity of a robust upper-level jet couplet with enhanced divergence aloft interacts with a moderately unstable airmass pooling northward across the Lower MS Valley and into a warm front gradually lifting north ahead of surface low pressure moving into the Arklatex. Very strong forcing is noted along this warm front with enhanced surface convergence and very strong moisture transport working in tandem with the instability to drive convection with enhanced rainfall rates. MLCAPE values of 1000 to 1500+ J/kg will advance northeast overnight with PWs as high as 1.5 to 1.7 inches given the strength and persistence of the low-level jet, and the upper-level jet support overnight is forecast to only strengthen as the aforementioned upper-level trough/closed low takes on a negative tilt as it pivots into the Lower MS Valley. The result will be widespread and sustainable convection with persistently high rainfall rates. The latest 00Z HREF guidance favors areas of training convection as the activity along the warm front becomes increasingly aligned with the deeper layer steering flow. Rainfall totals of as much as 3 to 6 inches will be possible across central/northeast AR into the MO Bootheel and possibly extreme northwest TN and western KY by dawn as the axis of most organized convection and heaviest rainfall rates arrives. Widespread and locally significant flash flooding is expected for these areas given the high hourly rainfall rates and storm total potential. In fact, there are some low-end probabilities showing up on the HREF of seeing rainfall amounts exceed the 100-year ARI for a 6-hour period. This suggests locally significant impacts. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5IlHPaVUp2BvU0JGnxZJkOyPGDpB3XHNmCMveXydGKDx12NvcBTx_QiWYWXMR13mjrFE= aYJDhWpZ_Vcp8qHZoU_YAPc$ for graphic product... ATTN...WFO...JAN...LSX...LZK...MEG...PAH...SGF...SHV...TSA... ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...OHRFC...NWC... LAT...LON 38318893 38088811 37198794 36168841 35508885=20 34508984 34089056 33769147 33769257 34019361=20 34629417 35399420 36049377 36929277 37599160=20 38059044=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .