1. Special Winter Weather Briefing 2/11/2012 www.srh.noaa.gov/shv/briefing Keith Stellman Warning Coordination Meteorologist National Weather Service Shreveport, Louisiana

2. Overview Sunday Night/Monday AM Sunday Night/Monday AM Arctic Air in place at the surface Arctic Air in place at the surface Upper level disturbance moving over top of the cold air Upper level disturbance moving over top of the cold air Prime time…3 AM – 9 AM with the heaviest occurring in the 6 – 9 AM timeframe Prime time…3 AM – 9 AM with the heaviest occurring in the 6 – 9 AM timeframe Snow/Sleet/Freezing Rain mixing with rain along and north of US 82. Snow/Sleet/Freezing Rain mixing with rain along and north of US 82. Possible Accumulations in McCurtain, Sevier, Howard, Little River, Hempstead, Nevada Counties Possible Accumulations in McCurtain, Sevier, Howard, Little River, Hempstead, Nevada Counties National Weather Service Shreveport, Louisiana

3. Big Picture National Weather Service Shreveport, Louisiana Monday Strong Upper Level Low Pressure Area H Arctic Surface High

4. 12:48 PM Radar Snow/Sleet Freezing Rain

5. Sleet/snow/Freezing rain Dilemma Temperature profile at Midnight Sun PM- DeQeen Freezing line High Res models suggest no precip at midnight..but temps cold enough for snow High Res models suggest no precip at midnight..but temps cold enough for snow Dry air at surface will help “wet bulb” effect Dry air at surface will help “wet bulb” effect Height Surface Tempeatures ~33

6. Sleet/snow/Freezing rain Dilemma Temperature profile at 3 AM Mon- Dequeen Freezing line High Res models suggest atmosphere is saturating… but differ on warm nose @ 5000’ sleet/snow to freezing rain High Res models suggest atmosphere is saturating… but differ on warm nose @ 5000’ sleet/snow to freezing rain Dry air at surface will help “wet bulb” effect Dry air at surface will help “wet bulb” effect Height Surface Tempeatures ~32

7. Sleet/snow/Freezing rain Dilemma Temperature profile at 6 AM Mon- Texarkana Freezing line Temp in mid levels ~32… suggests a snow/sleet mix Temp in mid levels ~32… suggests a snow/sleet mix Cold Nose in lowest 2000’ Cold Nose in lowest 2000’ Height Surface Tempeatures ~30-31

8. Sleet/snow/Freezing rain Dilemma Temperature profile at 9 AM Mon- Texarkana Freezing line Temp in mid levels >32… suggests a change to sleet/rain Temp in mid levels >32… suggests a change to sleet/rain Cold Nose in lowest 2000’ warming Cold Nose in lowest 2000’ warming Height Surface Tempeatures ~35

9. Timing.. Hi Res model radar forecast 3 AM 6 AM Precip on leading Edge may start as sleet/snow Freezing line

10. Timing.. Hi Res model radar forecast 9 AM Noon Freezing line

11. Temperatures Monday 3 AM6 AM

12. Temperatures Monday 9 AMNoon

13. 0.01” – 0.10” Ice/Sleet/Snow possible 0.10”-0.25” National Weather Service Shreveport, Louisiana ~Midnight~3AM ~6AM

14. Impacts Amounts of up to 0.10” of Ice/Sleet possible in the US 82 corridor of NE TX, South Arkansas Amounts of up to 0.10” of Ice/Sleet possible in the US 82 corridor of NE TX, South Arkansas Amounts of 0.10” – 0.25” in McCurtain, Amounts of 0.10” – 0.25” in McCurtain, Timing: After Midnight Sunday night...into Monday AM. Timing: After Midnight Sunday night...into Monday AM. Changing to more rain through Monday AM Changing to more rain through Monday AM Ground temps ~39 … in South Arkansas. Ground temps ~39 … in South Arkansas. Little or no issues in the I- 20 corridor expected Little or no issues in the I- 20 corridor expected Travel impacts mainly in rural areas along and north of US 82 through mid morning Monday AM Travel impacts mainly in rural areas along and north of US 82 through mid morning Monday AM

15. NEXT CONFERENCE CALL: Weekly Briefing on Thu Weekly Briefing on Thuwww.srh.noaa.gov/shv/briefing National Weather Service Shreveport, Louisiana