Special Winter Weather Briefing 2/3/2011 – 4 PM slides: Keith Stellman National Weather Service Shreveport, Louisiana

Overview Tonight/Friday Tonight/Friday Arctic air in place across the region Arctic air in place across the region Upper level system moves in and draws moisture in from the gulf over the cold air. Upper level system moves in and draws moisture in from the gulf over the cold air. Accumulations of 1-3 inches snow/minor sleet accumulations possible I-20 Corridor and south (Winter Weather Advisory area) Tyler>Longview>Shreveport>Magnolia>El Dorado and points south. Accumulations of 1-3 inches snow/minor sleet accumulations possible I-20 Corridor and south (Winter Weather Advisory area) Tyler>Longview>Shreveport>Magnolia>El Dorado and points south. Ice accumulations of inches possible…(Winter Storm Warning area) Lufkin->Nacogdoches>Natchitoches- >Winnfield>Monroe>Columbia>Colfax>Jena Ice accumulations of inches possible…(Winter Storm Warning area) Lufkin->Nacogdoches>Natchitoches- >Winnfield>Monroe>Columbia>Colfax>Jena Beginning this evening 6 pm ending by 6 pm Friday. (Winter precipitation north of the Winter Storm Warning area may begin a little later than 6 pm this evening.) Beginning this evening 6 pm ending by 6 pm Friday. (Winter precipitation north of the Winter Storm Warning area may begin a little later than 6 pm this evening.) National Weather Service Shreveport, Louisiana

Big Picture National Weather Service Shreveport, Louisiana Today Tngt Friday Strong Upper Level Low Pressure Area H Arctic Surface High

Current Radar/Temps – 3:15 PM Initial precip band moving north Temps still at or below Freezing

Sleet/snow/Freezing rain Dilemma Temperature profile at Midnight- Jena Freezing line High Res models suggest Freezing Rain in Jena with warm nose at ft (Southeast) High Res models suggest Freezing Rain in Jena with warm nose at ft (Southeast) Cold nose helps rain freeze quickly Cold nose helps rain freeze quickly Height Surface Tempeatures 28-32

Sleet/snow/Freezing rain Dilemma Temperature profile at Midnight- Monroe Freezing line High Res models suggest Mix with more Freezing Rain High Res models suggest Mix with more Freezing Rain Warm nose not as prevalent but deep enough to melt the snow into sleet/FZRA Warm nose not as prevalent but deep enough to melt the snow into sleet/FZRA Height Surface Tempeatures 27-30

Sleet/snow/Freezing rain Dilemma Temperature profile at Midnight- Natchitoches Freezing line Warm Nose appears and looks deep enough to melt the snow Warm Nose appears and looks deep enough to melt the snow Could either be sleet or freezing rain Could either be sleet or freezing rain Toledo Bend- >Natchitoche s->Jonesboro Toledo Bend- >Natchitoche s->Jonesboro Height Surface Tempeatures 28-31

Total Liquid Equivalent (precip amounts) 18Z High Res Model Run Model has backed off a bit on total amounts Model has backed off a bit on total amounts Generally > 0.25” of precip in Deep East TX, all of LA except NW. Generally > 0.25” of precip in Deep East TX, all of LA except NW.

Total Liquid Equivalent (precip amounts) Model Concensus (SREF) Model has reduced amounts slightly as well (0.50 is a max across the Southeast) Model has reduced amounts slightly as well (0.50 is a max across the Southeast) The 2” line The 2” line Rouge estimate of the mix line Rouge estimate of the mix line

Timing 3PM-6PM 6PM-9PM Midnight - 3 AM Heaviest starts occurring After 9 PM -> 6AM 3 AM – 6 AM 6 AM – 9 AM Light snow late morning tapering Off by ~noon

Temperatures Thursday Night - Friday LowsHighs

Impacts 1-2 inches snow/minor sleet accumulations possible I-20 Corridor and south (Winter Weather Advisory area) Tyler>Longview>Shreveport>M agnolia>El Dorado and points south. 1-2 inches snow/minor sleet accumulations possible I-20 Corridor and south (Winter Weather Advisory area) Tyler>Longview>Shreveport>M agnolia>El Dorado and points south. Isolated 3” amounts possible further south and east. Isolated 3” amounts possible further south and east. Lower visibilities after Midnight Lower visibilities after Midnight Ground temps ~40/35 in AR… Precip will stick to bridges/overpasses and main roadways Ground temps ~40/35 in AR… Precip will stick to bridges/overpasses and main roadways Cold temperatures through Saturday AM to keep it around Cold temperatures through Saturday AM to keep it around Ice accumulations of inches possible) Lufkin- >Nacogdoches>Natchitoc hes- >Winnfield>Monroe>Colu mbia>Colfax>Jena Ice accumulations of inches possible) Lufkin- >Nacogdoches>Natchitoc hes- >Winnfield>Monroe>Colu mbia>Colfax>Jena Over 0.50” would cause widespread Power outages Over 0.50” would cause widespread Power outages Only isolated areas in extreme Southeast Only isolated areas in extreme Southeast Instant freeze on all surfaces with temps in the 20s Instant freeze on all surfaces with temps in the 20s

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