SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0244 PM CDT Fri Sep 15 2023 Valid 152000Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN NEW MEXICO INTO WEST TEXAS... ...SUMMARY... Scattered large hail, isolated severe wind gusts, and a brief tornado or two are most likely across the southern High Plains into tonight. ...20z Update... The main change with the 20z update is the removal of the Marginal (level 1 of 5) risk across portions of MN/WI. Weak heating due to persistent cloud cover, coupled with modest boundary-layer moisture and weak midlevel lapse rates are resulting in MLCAPE around 500 J/kg or less. Additionally, vertical shear will remain somewhat low. Latest HRRR and RRFS guidance indicates very low storm coverage through this evening. Any stronger cells that do develop may produce small hail, but overall severe potential appears lower than previous expected. The previous outlook remains on track across the southern High Plains vicinity, and severe storms are expected into this evening and tonight. For more details, see previous discussion below. ..Leitman.. 09/15/2023 .PREV DISCUSSION... /ISSUED 1056 AM CDT Fri Sep 15 2023/ ...Eastern NM/West TX.. Visible satellite imagery shows mostly clear skies over eastern NM and west TX this morning, with weak east/northeasterly surface winds across the region. Surface dewpoints in the low/mid 60s are common, which combined with moderately steep mid-level lapse rates should yield MLCAPE values of 1500-2000 J/kg by late afternoon. Present indications are that scattered storms will form off the higher terrain of eastern NM after 21z as large scale forcing for ascent strengthens ahead of a shortwave trough now over the Four Corners region. These storms will track slowly eastward and intensify as they move into west TX this evening. Westerly mid/upper level winds will be sufficiently strong for a few supercells capable of large hail and locally gusty winds.
