SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0153 PM CST Wed Jan 06 2021 Valid 062000Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF EASTERN TEXAS... ...SUMMARY... Thunderstorm capable of damaging winds, hail, and a couple tornadoes are possible this afternoon and evening from southeastern Texas into southern Louisiana. ...Discussion... The ongoing outlook areas/reasoning continue to represent current expectations, with storms now ongoing over eastern Texas, a few of which are severe at this time. The main changes at this point will be to adjust areas on the western fringe of the outlook, to represent convective progression which has occurred since the prior outlook. Expect severe risk to continue this afternoon, and then diminish into the evening as a combination of airmass stabilization, and given weaker instability to the east of ongoing storms. ..Goss.. 01/06/2021 .PREV DISCUSSION... /ISSUED 1018 AM CST Wed Jan 06 2021/ ...SE TX... Latest water vapor loop shows an intense shortwave trough digging into OK/TX. An 80+ knot mid level jet will rotate into the base of the trough this afternoon and nose eastward across southeast TX and the LA coast. This will result in increasing large scale forcing and destabilization over this region, and aid in the development of thunderstorms. Storms have already begun to form along/ahead of the advancing cold front over central TX. Southerly low level winds ahead of the front will help transport low/mid 60s dewpoints northward, leading to sufficient afternoon CAPE for a few strong/severe storms. Forecast soundings show MLCAPE values around 1000 J/kg and strong deep-layer shear. Cooling temperatures aloft will promote the risk of hail in the stronger cells. Near-ground shear is not expected to be particularly strong, and linear/bowing structures are shown in most 12z CAM solutions. Therefore, it appears damaging winds are the main threat but with some risk of a tornado or two. Storms should move off the TX coast after dark, but strong convection may occur along and just off the LA coast through the night and possibly spread inland again over southeast LA towards dawn.
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