SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Thu Apr 27 2023 Valid 281200Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF NORTHERN INTO CENTRAL TEXAS... ...SUMMARY... Scattered storms are forecast to produce damaging hail from late afternoon through evening from north-central Texas to the middle and lower Rio Grande Valley. Isolated strong to severe storms may also occur over parts of the Southeast. ...Synopsis... A potent shortwave trough will drop south across CO, NM, and into the TX Panhandle through 00Z, with cooling aloft increasing late in the day over central to northern TX. Winds aloft will increase from 35 kt at 500 mb Friday morning to 55 kt by 00Z, enhancing shear. Low pressure will shift south toward the middle Rio Grande Valley, ahead of a plunging cold front into west TX. Low 60s F dewpoints will be in place over central TX Friday morning, increasing into the mid 60s F within a narrow plume as southerly 850 mb flow increases to 35 kt. The combination of strengthening shear and increasing moisture and instability will again result in supercells capable of damaging hail over parts of TX Friday afternoon and evening. To the east, a low-amplitude shortwave trough will pivot from the Carolinas into the Mid Atlantic, with moderate southwest flow aloft persisting. A decelerating cold front will stretch roughly from the Piedmont southwestward toward the northern Gulf Coast, with widespread 60s F dewpoints ahead of it. In addition, an effective boundary is forecast to make little northward progress over far northeast NC/southeast VA due to precipitation. Weak low pressure combined with surface heating may result in isolated strong storms over parts of the area. Elsewhere, a moist air mass will remain over FL, beneath a westerly flow regime. Temperatures aloft will be much warmer than the previous few days, but isolated strong storms may still occur over northern FL and the eastern Peninsula. ...North TX southward to the lower Rio Grande valley... Well in advance of the cold front, strong heating will lead to a plume of steep low-level lapse rates from southwest into central TX, west of I-35 by late afternoon. Meanwhile, returning moisture beneath very steep lapse rates aloft will lead to strong instability over much of the state. While initially capped, lift along the cold front will lead to rapid severe-storm development around 21Z over parts of northern/northwestern TX, developing southwestward into central TX. This northeast-to-southwest-oriented corridor of maximum threat potential may remain relatively concentrated due to the narrow moist plume and fast-moving cold front. However, the degree of instability coupled with rightward-propagating cells off the front support a 30% severe hail probability. In addition, a tornado or two may occur, especially over northern TX where SRH will be a bit stronger at 200+ m2/s2, but this will depend on storms not getting undercut. A substantial instability and CIN gradient will exist over eastern TX after 00Z, which will limit eastward extent of severe threat. Increasing CIN from the TX Coast westward may also limit storm coverage during the evening. Still, isolated cells and/or bows may persist over far southern TX overnight, as instability will be strong. ...Northern FL into the Carolinas... Storms may be ongoing early Friday across the FL Panhandle, with favorable instability and deep-layer shear favoring isolated strong storms. Activity across the Southeast overall is expected to be isolated, the exception being the warm-advection plume into eastern NC and VA. However, surface heating will result in a large area of MUCAPE over 1000 J/kg from GA into NC, beneath modest westerlies aloft. As such, any storms that develop along the deteriorating cold front may result in localized marginally severe hail or wind. During the late afternoon, additional storms may develop from central into eastern NC, coincident with the weak surface low and peak heating. Soundings show substantial dry air aloft, but also long, straight hodographs which may favor isolated hail. ..Jewell.. 04/27/2023
