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Special Special Winter Weather Winter Weather
BriefingBriefing2/3/2011 – 4 PM2/3/2011 – 4 PM
slides:slides:www.srh.noaa.gov/shv/briefingwww.srh.noaa.gov/shv/briefing
Keith StellmanKeith Stellman
National Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana
Overview Tonight/FridayTonight/Friday
Arctic air in place across the regionArctic air in place across the region Upper level system moves in and draws moisture in Upper level system moves in and draws moisture in
from the gulf over the cold air.from the gulf over the cold air. Accumulations of 1-3 inches snow/minor sleet Accumulations of 1-3 inches snow/minor sleet
accumulations possible I-20 Corridor and south accumulations possible I-20 Corridor and south (Winter Weather Advisory area) (Winter Weather Advisory area) Tyler>Longview>Shreveport>Magnolia>El Dorado Tyler>Longview>Shreveport>Magnolia>El Dorado and points south. and points south.
Ice accumulations of 0.25-0.50 inches possible…Ice accumulations of 0.25-0.50 inches possible…(Winter Storm Warning area) Lufkin-(Winter Storm Warning area) Lufkin->Nacogdoches>Natchitoches->Nacogdoches>Natchitoches->Winnfield>Monroe>Columbia>Colfax>Jena>Winnfield>Monroe>Columbia>Colfax>Jena
Beginning this evening 6 pm ending by 6 pm Friday. Beginning this evening 6 pm ending by 6 pm Friday. (Winter precipitation north of the Winter Storm (Winter precipitation north of the Winter Storm Warning area may begin a little later than 6 pm this Warning area may begin a little later than 6 pm this evening.) evening.)
National Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana
Big PictureBig Picture
National Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana
TodaTodayy
TngtTngt
FridFridayay
Strong Upper Level
Low Pressure Area
HHArctic Surface
High
Current Radar/Temps – 3:15 Current Radar/Temps – 3:15 PMPM
Initial precip band
moving north
Temps still at or below Freezing
Sleet/snow/Freezing rain Sleet/snow/Freezing rain DilemmaDilemma
Temperature profile at Midnight- Jena Temperature profile at Midnight- Jena
Free
zing
line
High Res High Res models models suggest suggest Freezing Freezing Rain in Rain in Jena with Jena with warm nose warm nose at 1000-at 1000-5000 ft 5000 ft (Southeast(Southeast))
Cold nose Cold nose helps rain helps rain freeze freeze quicklyquickly
Height
Surface Tempeatures 28-32
Sleet/snow/Freezing rain Sleet/snow/Freezing rain DilemmaDilemma
Temperature profile at Midnight- MonroeTemperature profile at Midnight- Monroe
Free
zing
line
High Res High Res models models suggest suggest Mix with Mix with more more Freezing Freezing Rain Rain
Warm Warm nose not nose not as as prevalent prevalent but deep but deep enough to enough to melt the melt the snow into snow into sleet/FZRAsleet/FZRA
Height
Surface Tempeatures 27-30
Sleet/snow/Freezing rain Sleet/snow/Freezing rain DilemmaDilemma
Temperature profile at Midnight- Temperature profile at Midnight- NatchitochesNatchitoches
Free
zing
line
Warm Warm Nose Nose appears appears and looks and looks deep deep enough to enough to melt the melt the snowsnow
Could Could either be either be sleet or sleet or freezing freezing rainrain
Toledo Toledo Bend-Bend->Natchito>Natchitoches-ches->Jonesbor>Jonesboroo
Height
Surface Tempeatures 28-31
Total Liquid Equivalent (precip Total Liquid Equivalent (precip amounts) amounts)
18Z High Res Model Run18Z High Res Model Run
Model has Model has backed off a backed off a bit on total bit on total amountsamounts
Generally > Generally > 0.25” of 0.25” of precip in precip in Deep East Deep East TX, all of TX, all of LA except LA except NW.NW.
Total Liquid Equivalent (precip Total Liquid Equivalent (precip amounts) amounts)
Model Concensus (SREF)Model Concensus (SREF)
Model has Model has reduced reduced amounts amounts slightly as slightly as well (0.50 is well (0.50 is a max across a max across the the Southeast)Southeast)
The 2” lineThe 2” line
Rouge Rouge estimate of estimate of the mix linethe mix line
TimingTiming3PM-6PM 6PM-9PM Midnight - 3 AM
Heaviest starts occurringAfter 9 PM -> 6AM
3 AM – 6 AM 6 AM – 9 AM
Light snow late morning taperingOff by ~noon
ImpactsImpacts 1-2 inches snow/minor 1-2 inches snow/minor sleet accumulations sleet accumulations possible I-20 Corridor and possible I-20 Corridor and south (Winter Weather south (Winter Weather Advisory area) Advisory area) Tyler>Longview>ShrevepoTyler>Longview>Shreveport>Magnolia>El Dorado rt>Magnolia>El Dorado and points south.and points south.
Isolated 3” amounts Isolated 3” amounts possible further south and possible further south and east.east.
Lower visibilities after Lower visibilities after MidnightMidnight
Ground temps ~40/35 in Ground temps ~40/35 in AR… AR… Precip will stick to Precip will stick to bridges/overpasses and bridges/overpasses and main roadwaysmain roadways
Cold temperatures Cold temperatures through Saturday AM through Saturday AM to keep it aroundto keep it around
Ice accumulations of Ice accumulations of 0.25-0.50 inches 0.25-0.50 inches possible) Lufkin-possible) Lufkin->Nacogdoches>Natch>Nacogdoches>Natchitoches-itoches->Winnfield>Monroe>>Winnfield>Monroe>Columbia>Colfax>JenColumbia>Colfax>Jenaa
Over 0.50” would Over 0.50” would cause widespread cause widespread Power outagesPower outages Only isolated areas in Only isolated areas in
extreme Southeastextreme Southeast Instant freeze on all Instant freeze on all
surfaces with temps surfaces with temps in the 20sin the 20s