• UTC: 2019-02-17 20:35

tornado/severe thunderstorm watches

  • SPC - No MDs are in effect as of Sun Feb 17 13:23:01 UTC 2019
    on February 17, 2019 at 1:22 pm

    No Mesoscale Discussions are in effect as of Sun Feb 17 13:23:01 UTC 2019. […]

  • SPC - No watches are valid as of Sun Feb 17 13:23:01 UTC 2019
    on February 17, 2019 at 1:22 pm

    No watches are valid as of Sun Feb 17 13:23:01 UTC 2019. […]

  • SPC Feb 17, 2019 1300 UTC Day 1 Convective Outlook
    on February 17, 2019 at 12:34 pm

    SPC 1300Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0628 AM CST Sun Feb 17 2019 Valid 171300Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are expected over portions of the Southeast today. ...Synopsis... Broad upper troughing will persist across the CONUS during the period, with strong mid/upper-level (i.e. over 100 kt at 500 mb and over 170 kt at 250 mb) flow extending throughout the southern periphery of the trough. Recent water vapor imagery reveals several shortwaves embedded within this fast flow aloft. The lead shortwave is currently moving through northern MO with a continued east-northeastward motion taking this system into the Great Lakes region by 00Z. Another shortwave is currently moving southeastward along the southern CA coast. Progression of this shortwave will gradually become more eastward as it moves quickly across the Southwest and into the southern High Plains. Lastly, shortwave currently off the coast of British Columbia will continue quickly southward, likely reaching coastal central CA by the end of the period. At the surface, primary feature is the developing low currently near the AR/TN/AL border intersection. This low is expected to deepen as it moves just ahead and to the south of its parent shortwave trough. By 00Z, this low will likely be centered near the KY/WV border with its attendant cold front extending southwestward through middle TN, northern AL, east-central MS, and south-central LA. ...Southeast into the southern Appalachians... Showers and occasional thunderstorms are anticipated along and behind the cold front sweeping through the region. Relatively warm temperatures aloft (resulting from the prevailing southwesterly flow throughout much of the troposphere) and displacement of the stronger lift farther north will result in poor lapse rates and minimal instability. Consequently (and in spite of strong vertical shear), updraft strength/persistence will be tempered and the severe threat minimal. ...Northern/Central CA Coast... A few lightning strikes were observed near the coast earlier this morning where forcing for ascent within the exit region of a mid-level jet streak was able briefly overcome convective inhibition across the region. Expectation is for the environment to become increasingly hostile to deep convection amidst relatively cool and dry low levels. Some shallow convection is likely but updrafts reaching temperatures needed for lightning production will be sparse. As such, lightning coverage is expected to be less than 10% and the general thunder line was removed. ..Mosier.. 02/17/2019 Read mor […]

  • SPC Feb 17, 2019 Day 4-8 Severe Weather Outlook
    on February 17, 2019 at 9:55 am

    Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0348 AM CST Sun Feb 17 2019 Valid 201200Z - 251200Z ...DISCUSSION... Blocking appears likely to remain prominent within the mid-latitude westerlies across the northeastern Pacific through this period. Downstream, models currently suggest that flow may transition to a broadly confluent regime across the Pacific coast, Rockies and Plains, and less amplified across the southern tier of the U.S. by late next weekend. As this takes place, it appears that one more vigorous short wave impulse will accelerate east-northeastward out of the Four Corners states. Models suggest that there may be sufficient preceding modification of the low-level environment to the lee of the southern Rockies to allow for significant cyclogenesis to ensue, from the central/southern Plains through the lower Great Lakes region, during the course of next weekend. Current model depictions are suggestive that this could be accompanied by at least some organized severe weather potential. However the spread among the various models, and within their respective ensemble output, concerning this evolving system becomes substantial due to the extended time range, among other potential factors. This contributes to sizable lingering uncertainties that result in the maintenance of severe probabilities at less than 15 percent. Read mor […]