Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Dec 09 2022 06:27:43 AWUS01 KWNH 090627 FFGMPD MSZ000-ARZ000-TXZ000-OKZ000-091130- Mesoscale Precipitation Discussion 1146 NWS Weather Prediction Center College Park MD 127 AM EST Fri Dec 09 2022 Areas affected...Southern AR...Northwest MS...Ext Northeast TX... Concerning...Heavy rainfall...Flash flooding possible Valid 090625Z - 091130Z SUMMARY...Training shallow thunderstorms with short-term bursts of up to .5"/15min and narrow stripe of 2-2.5" local maxima on threshold to result in possible widely scattered low-end flooding risk through early morning. DISCUSSION...An enhanced area of modest but unseasonably high theta-E air indicated by mid 60s Tds resides along an old ill defined surface front across northern Texas out of the DFW metro across S AR before intersecting with the sharpening stationary front across N MS. GOES-E WV suite depicts a well defined closed low across the northern Plains with a dry punch associated with mid to upper level jet core across KS progressing the occluded front across IA/MO before angling south. A weak low across the OK/AR border is leading the cold front south-southeast. These weak shortwave height-falls continue to support strong confluent low level flow with best 850mb convergence across far Northeast TX across S AR. The higher moisture and modest lapse rates allows for pooled moisture to 1.5", while also supporting weak 500 J/kg MUCAPE isentropically ascending across the older frontal zone.=20 This instability and encroaching DPVA is allowing for increasing convective activity across NE TX to S AR, with scattered cooling tops just below -50C. Given deep moisture/flux convergence of 15-25kts and higher than normal deep layer RH values (700mb 90%+), rainfall efficiency is going to support short-term bursts of .5" in about 15 minutes. Deep layer flow is strong, but is highly unidirectional to the confluent low level flow/forcing supporting a training profile. Given weak instability, cores are not likely to be too broad, but likely sufficient for repeating/training nature at least over the next few hours across TX/SW AR before the cold front undercuts the ascent pattern; and the focus shifts eastward toward SE AR into NW MS. Given repeating, there is a hint for some narrow streaks of 2"+ totals. While AHPS precip anomalies are slightly below average for the last week or two, NASA LIS relative soil moisture values are in the 50-65% range, slowly increasing across to N MS. While the first cells are likely to saturate the top layer of soils, the secondary/repeating cells may support increased runoff and a very low chance resulting in highly localized flooding concern through 12z. Not only limited in areal coverage for any flooding, but also likely to only result in the low-end flooding risk...but still a non-zero threat through 12z, enough to be considered possible across this narrow area of concern. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-qRgYtMFrQ7Kh-VvnSa1rXzIOVLM3y3n7yg3SwhvW9uh1h4ikyWWWGIGZvoz0PbMUcPl= n04FBxFa1LD0dRMYDhYxCX4$ for graphic product... ATTN...WFO...JAN...LZK...MEG...SHV... ATTN...RFC...ABRFC...LMRFC...NWC... LAT...LON 34618995 34478922 33828932 33459131 33289256=20 33099398 33069453 33109512 33499521 33789481=20 34419196=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) .