Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 09 2023 03:03:32 AWUS01 KWNH 090303 FFGMPD TXZ000-OKZ000-KSZ000-COZ000-NMZ000-090900- Mesoscale Precipitation Discussion 0669 NWS Weather Prediction Center College Park MD 1102 PM EDT Sat Jul 08 2023 Areas affected...Southeast CO, southwest KS, western OK, TX Panhandle Concerning...Heavy rainfall...Flash flooding likely Valid 090301Z - 090900Z Summary...Convection organizing into an MCS over the High Plains of CO and KS will strengthen and drop southward tonight. Rainfall rates of 2-3"/hr are likely within the more intense convection, which through training could produce 2-4" of rain with locally higher amounts. Flash flooding is likely. Discussion...The regional radar mosaic this evening indicates expanding thunderstorms moving across southeast CO and western KS. These thunderstorms are beginning to cluster within SPC RAP analyzed effective bulk shear of 50-70 kts, and it is likely this will become an intense MCS tonight. Fueling this convection is an intensifying LLJ which is ejecting out of the TX panhandle and reaching 20-30 kts out of the S/SE on regional VWPs. This LLJ is helping to transport PWs of 1.4-1.5 inches in the pre-convective environment, and advect MUCAPE of 2000-3000 J/kg northward. This is fueling the already impressive rain rates estimated via KPUX and KDDC radars at 2-2.5"/hr. With the environment becoming even more favorable during the next few hours in response to the surging LLJ, there is high confidence this cluster will organize into an potent MCS. The high-res models are in good agreement with this evolution, and although some spatial differences exist, the HREF EAS probabilities for 1"/6hrs peak above 50% in northwest OK, adding to the confidence in a heavy rain event. The persistent LLJ will keep the downstream environment ripe for intense convection, with ascent likely increasing the next few hours as the LLJ locally backs downstream of the MCS to isentropically ascend more orthogonally to the wavering stationary front. The intense ascent into the extreme thermodynamics will support rain rates in excess of 2"/hr according to the HREF probabilities, with the HRRR indicating 15-min rainfall exceeding 1" in some areas (short-term 4+"/hr rates). The flash flood risk may be somewhat inhibited by progressive storm motions noted via Corfidi vectors of 40 kts, but these rain rates will likely still overwhelm soils. Additionally, where any training can occur near developing MCVs, 2-4" of rain with locally higher amounts is likely. Soils across this area are quite saturated already from widespread 7-day rainfall that is 300-600% of normal, resulting in USGS streamflow anomalies that are almost uniformly above the 90th percentile. FFG is compromised due to this recent rainfall, falling to just 1-1.5"/3hrs. These intense rain rates falling atop these saturated soils will likely yield scattered instances of flash flooding through the night. Weiss ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-1MW1UvDSgf097hr4O2WriLCls9AwwIpHTzihAs7EOp9R7yYnZTh9fAttYj4pTl5pT9U= LOQP1jQ0iKH9WB6CdFfPuHc$ for graphic product... ATTN...WFO...ABQ...AMA...BOU...DDC...GLD...ICT...LUB...OUN... PUB... ATTN...RFC...ABRFC...MBRFC...NWC... LAT...LON 38560248 38510098 38119917 37579834 36829788=20 35739784 34949808 34609853 34389980 34390049=20 34600108 35190167 35930211 36730279 37070315=20 37370385 37510438 37690479 37980488 38320435=20 38550322=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) .