Special Winter Weather Briefing 1/9/2010 slides: Keith Stellman National Weather Service Shreveport, Louisiana

Overview Today(Sunday) 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 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 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 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) 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/ Lufkin->Many->Jena: Mostly rain. Some sleet mixing in. Brief changeover at the end. Maybe a dusting. Freezing rain/sleet in Grant/Winn/ Monday Monday Freezing drizzle possible after midnight through early AM Freezing drizzle possible after midnight through early AM Light flurries early AM across I-30 corridor Light flurries early AM across I-30 corridor AM Temperatures ≤ 32 areawide, AM Temperatures ≤ 32 areawide, Upper 20’s along/north US 82 (Clarksville ->El Dorado) Upper 20’s along/north US 82 (Clarksville ->El Dorado) National Weather Service Shreveport, Louisiana

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

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

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

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

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

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

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

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

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

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

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

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

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

NEXT CONFERENCE CALL: Thursday 10 AM (regular briefing) Unless otherwise noted National Weather Service Shreveport, Louisiana