A robust surface low is projected to slide over the Great Lakes on Monday. A trailing cold front will move through the Arklatex region into the Mississippi River Valley by early afternoon. Ahead of the cold front, a strong southerly flow will help pump warm moist air into the region. A strong low level jet (around 50-60kts) is expected to take shape over much of the Mississippi and Tennessee River Valleys.
Right now, all SVR threats are possible given current parameters. Surface based CAPE will be roughly around 1000 to 1100 J/kg as mid level lapse rates steepen in response to a (modest) EML. This differential advection inversion will help cap us off early; however, storms should initiate near the Mississippi River around midday (due to surface heating and front frontal lifting) and progress steadily eastward through the afternoon hours. SRH is expected to be modest early on; however, as the frontal boundary nears, SRH will increase to 250-300 m2s2. Large hail and damaging winds will likely be the main threat with this squall line; however, given vertical shear profiles, isolated tornadoes will also be possible across the entire region. If surface winds back a bit more, the risk for tornadoes will increase dramatically. If discrete storms form ahead of the squall line, storms will have the potential for large hail, damaging winds, and tornadoes. With sharply curved hodographs out ahead of the cold front, some tornadoes may be strong and long tracked. However, at this time that potential is low and only exists well north of the Sequatchie Valley. There is a bit of uncertainty in the timing of the event and some SVR parameters will still need to be evaluated as the event nears.
General Forecast:
Monday:
Increasing Clouds and windy. Widespread showers and Thunderstorms (some will be severe) will move into the region by early evening. High temperatures will top out in the mid to upper 70’s. Southerly winds of 10-20 mph are expected with higher gusts. (Much higher gusts expected in thunderstorms)
Monday Night: Showers and thunderstorms early. Wind shifting from southerly to northwesterly with the passage of the cold front. Lows will bottom out in the lower to mid 40’s.
It is advised that all residents in the Sequatchie Valley stay aware of the weather situation Monday Afternoon. Be ready to act if severe weather watches/warnings are issued by the National Weather Service. Also, make sure your weather radio is in working order and in alert mode.
Meteorologist: Robert Frye
Updated: 4/3/11 at 12:45 AM
