National Weather Service United States Department of Commerce

Snow Will Persist in the Northeast and Great Lake States

Heavy Lake Effect snow will continue to the lee of the Great Lakes for the next couple of days. Snow will also return to the Northeast by Tuesday as another front moves in. Bitter cold wind chills can be expected in the Upper Mississippi Valley. Freezing temperatures will even impact central Florida. Meanwhile, elevated fire weather conditions will persist in southern California. Read More >

With an elevated fire weather threat today, here are some tips to help prevent wildfires!
It's quite chilly this morning with temperatures in the teens and 20s across most of the region, with a few spots in the lower 30s.
Did you know that the shortest day of the year is just a few days away? On that day, we (North & Central TX) will have approximately 10 hours of daylight. This is around 4 hours less daylight than on June Solstice. The Winter Solstice (when we start the astronomical winter) will be on Thursday December 21st, 2017.

 
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Automatically generated image showing areas of storm relative helicity.

 

Thumbnail of an automatically generated image showing areas of storm relative helicity. Thumbnail of an automatically generated image showing areas of storm relative helicity. Thumbnail of an automatically generated image showing areas of storm relative helicity.
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Helicity (0-1 Km) 

This is the 0-1 km (approximately 0-3,000 Ft. AGL) storm relative helicity which is a measure of the amount of low level wind shear available for tornadogenesis. This is not a good indicator of supercell potential which is related more strongly to 0-6 KM vertical shear. Values greater than 100 m**2/s**2, do suggest an increased threat of tornadoes provided a supercell is present.  Larger values are generally better, but there are no clear "boundaries" between non-tornadic and significant tornadic supercells.

The arrows indicate the approximate right supercell storm motion using the Bunkers technique.

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