Special Winter Weather Briefing 1/9/2010 slides: srh.noaa/shv/briefing

1. Special Winter Weather Briefing1/9/2010slides:www.srh.noaa.gov/shv/briefing Keith Stellman National Weather Service Shreveport, Louisiana

2. Overview Today(Sunday) East TX south of I-20: Rain mixing with sleet through early afternoon. Changing to all snow after noon. Accumulations of 2-4” possible NE TX north of I-20: Sleet early changing to snow. Accumulations 3-6” with higher amounts possible toward TXK SW AR and SE OK: Mostly snow. Accumulations highest in I-30 of 4-6” with some higher possible North LA I-20 corridor north: Freezing rain, sleet, snow mix. Freezing rain/sleet early through early Afternoon..becoming all snow. Accumulations highest along AR/LA line of 4-5” I-20 corridor 1-3”. Ice Accumulations of 0.5 – 1.00” (includes sleet) Lufkin->Many->Jena: Mostly rain. Some sleet mixing in. Brief changeover at the end. Maybe a dusting. Freezing rain/sleet in Grant/Winn/ Monday Freezing drizzle possible after midnight through early AM Light flurries early AM across I-30 corridor AM Temperatures ≤ 32 areawide, Upper 20’s along/north US 82 (Clarksville ->El Dorado) National Weather Service Shreveport, Louisiana

3. Radar/Observations (830AM) Freezing line National Weather Service Shreveport, Louisiana

4. Winter Storm Warnings • All included except southern row. • Snow threat greatest north. • Freezing rain/sleet/snow central (I-20)

5. Sleet/snow/Freezing rain changeTemperature profile at Noon Sunday - Shreveport • Warm nose 200-4000 feet a little cooler • Will likely see mixed bag through noon • Further north..all snow. West, rain/sleet as warm nose is bigger Freezing line Surface Tempeatures 28-31 Height

6. Sleet/snow/Freezing rain DilemmaTemperature profile at 3 PM Sunday - Shreveport • Warm Nose disappears • Precip would become all snow Noon • Snow would fall onto any ice/sleet accumulations • Northern LA Freezing line Surface Tempeatures 28-31 Height

7. Ice Accumulation Probabilities • Greatest risk along I-20..especially in North LA. Risk increases east. • Amounts generally 0.25-0.50” in green area…higher amounts possible eastern Parishes up to 1” • Through 4PM

8. Snow Probabilities > 4” • Greatest risk along I-30..especially in North LA. Risk increases north. • Amounts generally 4-6” Red • 2-4” Green • 1-2” Blue • North all snow • Middle change ~noon-3PM

9. Timing: Noon NAM Model • Rain East TX mixing in • Mix elsewhere except north

10. Timing: 3 PM • Becoming mostly snow as upper low moves in • Heavy snows near the upper low (blue banded areas NAM Model

11. Timing: 6PM NAM Model • Precip tapering off west and southwest. • Heaviest snows in I-30 • Mixed bag east

12. National Center Snow Forecast (issued 6 AM Sunday) • Higher amounts north where warm nose keeps precip mostly snow • Amounts lesser where sleet/freezing rain mixes in

13. Overall Forecast (issued 6 AM Sunday) • Higher amounts north where warm nose keeps precip mostly snow • Amounts lesser where sleet/freezing rain mixes in

14. Monday (with snowpack, highs/lows could be colder) Weather Highs Freezing Drizzle possible as temperatures aloft warm above freezing Arctic Air Moving In

15. Impacts • Heavy snows possible late Sunday AM through early Monday AM (I-20 north) • Lower visibilities • Slushy roads in heavier sleet/snows • Heavy wet snows can weigh on pine trees and come down on powerlines • Cold temperatures through mid-week keep snows around • Pipe freezing issues, if temperatures remain <35 through mid week • If Freezing I-20 corridor: 0.25-0.50” • Snow will fall onto FZRA Sunday • Mainly North LA, but could spill into NE TX and Southern AR • Obvious travel issues • Power outages • Freezing Drizzle overnight areawide possible

16. NEXT CONFERENCE CALL: Thursday 10 AM (regular briefing) Unless otherwise noted www.srh.noaa.gov/shv/briefing National Weather Service Shreveport, Louisiana