Tuesday, May 1, 2012

Severe weather situation unfolding for Tuesday

The focal point for thunderstorms, some of which could be severe will be found in the warm sector of a lifting warm front during the day on Tuesday.

aniwarmfront_050112

This warm front will allow temperatures to soar to near 80 degrees across southern Minnesota during the afternoon with dew points into the 60s behind the front.

Eurotemps_05012012

wrfGL_2_dewp_24

This will create enough instability for severe thunderstorms during the latter half of the day.  The darker colors below are where conditions will come together for the best chance of severe weather.

NAM_221_2012050100_F21_EHI_3000_M

Where the jet stream intersects with the warm front will be the most favorable area for a few tornado threat if convection can become rooted in the boundary layer.  This includes the Interstate 35 corridor north of the Twin Cities from near Hinckley to just south of Duluth.  Shear is not terribly impressive, so I don’t think we’ll see any kind of tornado outbreak today.

wrfGL_250_spd_24

NAM_221_2012050100_F24_EHI_1000_M

The low-level jet, which typically strengthens at night, increases to 40 knots by 7 PM and enhancing the thunderstorm risk for the Twin Cities metro and areas along Interstate 35.  It is around this time where I feel conditions are most favorable for severe thunderstorms.  I don’t think tornadoes are as favorable in the Twin Cities.  The primary threats for MSP will be large hail and damaging winds.

wrfGL_850_spd_24

“The big if”  Cloud cover will play a big role in whether we see severe weather Tuesday as this will limit instability.  With marginal wind shear, instability will absolutely be necessary for storms to form and survive.  If clearing does not occur until the afternoon, then expect regular thunderstorms throughout the day.

Current satellite shows clouds from showers and thunderstorms across north central Minnesota.  Timing will be everything.

clouds_sfcplots_05012012

The NAM, GFS, and Euro model all depict some degree of cloudiness by midday:

USA_TCDC_clm_017

USA_TCDC_clm_012

Euroclouds_05012012

If clearing happens before noon, then I expect storms to initiate across southwestern Minnesota during the early afternoon by 2 PM near the warm front with more storms firing to the northeast across the state along the boundary layer. As convection moves eastward, it should approach the eastern half of the state by 5 PM and into the Twin Cities by 6 PM. Between 6 and 9 PM is the time table for any rough weather to roll through the metro.

1ref_t2sfc_f15

1kmsimradar_120501_00z

As always, more updates will be posted as they become warranted!

RS

1 comment:

  1. Great post Ryan! Good luck if you chase Today.

    ReplyDelete