Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jul 10 2024 17:31:34 AWUS01 KWNH 101731 FFGMPD TXZ000-NMZ000-102330- Mesoscale Precipitation Discussion 0602 NWS Weather Prediction Center College Park MD 130 PM EDT Wed Jul 10 2024 Areas affected...Southern New Mexico, including the Sacramento Mountains Concerning...Heavy rainfall...Flash flooding possible Valid 101730Z - 102330Z Summary...Scattered showers and thunderstorms will develop and move slowly across New Mexico this afternoon. Rainfall rates at times will likely exceed 1"/hr, which could produce locally as much as 3 inches of rain. This will result in rapid runoff, with instances of flash flooding possible across sensitive terrain and burn scars. Discussion...The GOES-E visible imagery this afternoon indicates rapid Cu and TCu development over the Sacramento Mountains of NM, coincident with a rapid increase of instability noted by 3-hr SBCAPE change from the SPC RAP of 600-1000 J/kg. This surging instability is primarily due to warming beneath full sunshine on the periphery of an upper ridge centered across the Desert Southwest, with subtly lowered heights and a weak embedded impulse aiding in ascent over NM. At the same time, low-level flow is lifting out of the Gulf of Mexico and up the Rio Grande Valley, driving PWs to as high as 1.1 inches, which is above the 75th percentile according to the SPC sounding climatology. The 12Z U/A sounding out of KEPZ indicated freezing levels above 12,000 ft and mid-level lapse rates near moist-adiabatic levels, indicating the potential for efficient warm rain processes as storms rapidly blossom through the afternoon. During the next few hours, it is likely that convection will expand across southern New Mexico within these favorable thermodynamics, with intensification occurring as SBCAPE climbs above 1000 J/kg. This suggests storms will fire initially along higher terrain features, and then drift slowly southward due to 0-6km mean winds that are just around 5 kts. Limited bulk shear suggests storms will generally be of the pulse variety, but storm collisions and brief terrain-tying could enhance and increase heavy rainfall residence times in some areas. Both the HREF and REFS indicate a high (above 60%) probability for 1"/hr rain rates, while the sub-hourly HRRR suggests locally 0.25-0.5" of rain in 15 minutes. Any location that receives multiple rounds of these heavy rain rates, or where any storm/terrain interaction can result in longer residence times, locally as much as 3" of rain is possible as reflected by HREF 3"/6hr probabilities as high as 10%. Both the HREF and REFS probabilities favor the greatest risk for heavy rainfall to be across the Sacramento Mountains where FFG is only around 1.5"/3hrs, and likely even lower across the multiple vulnerable burn scars in that region. Instances of flash flooding this afternoon should be isolated due to the scattered nature of the convection, but if any storm lingers in the sensitive terrain, especially atop recent burn scars, flash flooding would be likely. Weiss ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-cudrv_zfpJS1Xik7OW6paan2jgfZshRLYQ94pcN9GWfcifXrjSB2hnbjxZY91tJbYQl= ZmF4fB-CKA0-Y1X4dUmWCiU$ for graphic product... ATTN...WFO...ABQ...EPZ...MAF... ATTN...RFC...WGRFC...NWC... LAT...LON 34920548 34770508 34090492 33370497 33070495=20 32750461 32310447 31800462 31750534 31860597=20 32470649 33460659 34400637 34810607=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .