Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Feb 08 2023 03:51:27 AWUS01 KWNH 080351 FFGMPD ARZ000-TXZ000-OKZ000-080900- Mesoscale Precipitation Discussion 0055 NWS Weather Prediction Center College Park MD 1050 PM EST Tue Feb 07 2023 Areas affected...Northeast TX...Southeast OK...Ext Southwest AR... Concerning...Heavy rainfall...Flash flooding possible Valid 080350Z - 080900Z SUMMARY...Persistent over-running with embedded isolated to scattered stronger updrafts capable of repeating/training may induce isolated incidents of low-end flash flooding into the early morning hours across northeast TX into far southeast OK and perhaps adjacent AR. DISCUSSION...03z surface analysis depicts a weak wave near CRS with well defined cold front in RADAR/convergence fields extending south-southwest toward AUS before angling more westward south of UVA. A warm front extend ENE to JXI to ELD and into the TN Valley. While the convergence is strong with nearly opposing directional flow across Central TX, the front is slow to progress eastward as upper level trof over NM remains more positive tilt with subtle shortwave ridging across E TX into OK at this time.=20 Still, ample diffluence and proximity to right entrance to upper level jet and FGEN support over OK/AR, the low level jet is strengthening with 30kts expected to increase to 35-40kts through the evening due to increased confluence of the flow (pinched from the west and east as the prior wave exits).=20 Overall, this provides a prolonged isentropic WAA ascent pattern maintained by strong surface based moisture convergence along the cold front near the surface wave. Solid moisture is available and increasing given arrival of low to mid-level moisture off the Pacific as well as sfc to low level moisture from the Western Gulf. Total PWATs will increase to 1.5" and while this is not helping to increase lapse rates, the theta-E advection will increase through the morning slowly rising instability from 500 J/kg toward 1000 J/kg. As such, convection will not be highly focused but scattered in nature and may allow for localized areas of maximized convergence near the surface low allowing for back-building development along the flanking lines as more mature cells track northward toward/across the Red River slowly weakening with time. Rates of 1.5"/hr are possible with 15-min totals of ..5-.6" per recent HRRR runs. Given the potential for repeating/training streets in the broader isentropic ascent region, isolated totals of 2-3" are probable in 3-6hr period.=20 NASA SPoRT relative soil moisture values and 0-40cm percentile values supported by 14 day AHPS precipitation anomaly values are normal to slightly above normal from College Station to Tyler to near Texarkana and eastward. Yet, FFG values are back to normal and much more elevated (above 2-2.5"/hr and greater than 3"/3hrs) which seem unlikely to be eclipsed, though the opposite is true around I-35 into portions of Northeast TX/SE OK... where FFG values are more in the range of potential exceedance by the expected 2-3" totals, yet are generally at or below average for soil moisture ratios. This adds some uncertainty to hydrological response to the aforementioned rates and 3-6hr localized totals...still, given dormant ground conditions, a few incidents of flash flooding are possible through the early morning hours, with greatest concerns along and just north of the surface low. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5YJkgRF0nP3tHbfRpAl88W2_KcCC43lRHDMFCbLxkdEZnq5Q4fFMmpG_A8zmTZu8JQfQ= CoF_txBcc2x_kOA5XD_UVKE$ for graphic product... ATTN...WFO...FWD...LZK...OUN...SHV...TSA... ATTN...RFC...ABRFC...LMRFC...WGRFC...NWC... LAT...LON 34589498 34459427 33879415 33049469 32459538=20 31539646 32029709 33609655 34289599=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) .