SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Tue Nov 02 2021 Valid 021300Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears minimal through tonight. ...Synopsis... The large-scale mid/upper pattern this period will be characterized by mean eastern troughing and western ridging, with amplification of the mean ridge through the period. For now, a belt of westerlies across the Great Basin and Intermountain West is located south of the strongest part of the ridge over Canada. An embedded shortwave trough -- evident in moisture-channel imagery from southern UT to northern Baja -- is forecast to move east-southeastward through the period. This trough should reach the TX Panhandle, southeastern NM and the ELP/LRU area by 00Z, then weaken as it crosses the southern Plains in advance of a trailing perturbation now near the ID/UT/NV border confluence. Preceding that feature, elevated low-level warm advection, moisture transport, and marginally favorable lapse rates will enable buoyancy in icing/lightning-production layers over much of central/southern OK and west-central to north TX through the period. This will support episodic and mostly isolated thunderstorms, mainly poleward of a surface frontal zone now located from the Arklatex to west- central TX and southeastern NM. Isolated thunder also may occur from convection moving eastward to southeastward over a corridor from south-central WY to central CO, in a zone of large-scale lift ahead of the current ID/UT/NV perturbation. A few lightning strikes also may be noted with convection that will be relatively shallow, but still potentially accessing steep low/middle-level lapse rates and suitable lightning-generation layers in the lee of parts of the Great Lakes. ...TX Davis Mountains/Big Bend region... A conditional and isolated convective/severe threat may develop this afternoon just downshear from the Davis/Chisos Mountains corridor this afternoon. Strong veering of wind with height near the front contributes to effective-shear magnitudes of 40-50 kt in forecast soundings, which also show a brief period of minimal MLCINH during mid/late afternoon's warmest period. Any convection that can develop off the higher terrain and sustain itself east-northeastward over or near the Big Bend area may evolve into a supercell. However, given that the mid/upper perturbation times slowly with respect to this area, with related large-scale lift lagging to the north/northwest, and the very localized, uncertain potential for convection to mature into stronger capping to the east, the potential appears too conditional for a categorical outlook area at this time. Mesoscale diagnostic and prognostic trends will be monitored for a more-confident storm genesis/maintenance scenario. ..Edwards.. 11/02/2021 Read more LIVE: spc.noaa.gov
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