Special Special Winter Weather Winter Weather
BriefingBriefing2/3/20112/3/2011slides:slides:
www.srh.noaa.gov/shv/briefingwww.srh.noaa.gov/shv/briefingKeith 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
HH
Current Radar/Temps Current Radar/Temps – 8 AM– 8 AM
Snow/Sleet
•1” in Mansfield LA
• Some melt/refreeze occurring
Reason for the earlier Reason for the earlier onsetonset
Models Models underestimatinunderestimating winds at g winds at 700mb700mb
Palestine and Palestine and Winnfield wind Winnfield wind profiler show profiler show 30-35 kts of 30-35 kts of wind at 10000ftwind at 10000ft
Models show Models show 20-25 kts20-25 kts
Sleet/snow/Freezing rain Sleet/snow/Freezing rain DilemmaDilemma
Temperature profile at Midnight- Lufkin Temperature profile at Midnight- Lufkin
Free
zing
line
High Res High Res models models suggest all suggest all snow East snow East Texas - Texas - LufkinLufkin
Very Very SaturatedSaturated… … moderate moderate to heavy to heavy snowsnow
Height
Surface Tempeatures 25-28
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 Jena (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
Model Forecast Noon Model Forecast Noon TodayToday
Snow to Sleet/Freezing Rain Line
• Models Models waver on waver on the mix the mix line. line.
• Blue Blue barbs barbs indicate indicate south south winds winds transporttransporting ing moisture moisture northnorth
Model Forecast 6 PM Model Forecast 6 PM TodayToday
Snow to Sleet/Freezing Rain Line
• Models Models waver on waver on the mix the mix line. line.
• Blue Blue barbs barbs indicate indicate south south winds winds transporttransporting ing moisture moisture northnorth
Total Liquid Equivalent (precip Total Liquid Equivalent (precip amounts) amounts)
High Res ModelHigh Res Model This model This model
has has consistently consistently shown a shown a swath of swath of precip precip across the across the northwestnorthwest
Generally > Generally > 0.25” of 0.25” of precip in precip in Deep East Deep East TX, all of TX, all of LA.LA.
Total Liquid Equivalent (precip Total Liquid Equivalent (precip amounts) amounts)
Model Concensus (SREF)Model Concensus (SREF) This blend This blend
shows the shows the highest swath highest swath in the in the Southeast and Southeast and south (0.50-south (0.50-1.00”) 1.00”)
Sabine, Sabine, Natchitoches, Natchitoches, Grant, Winn, Grant, Winn, La Salle, La Salle, CaldwellCaldwell
The 2” lineThe 2” line
Rouge Rouge estimate of the estimate of the mix linemix 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
Winter Storm Winter Storm Warning/Advisory (6 pm Warning/Advisory (6 pm this evening through 6 this evening through 6
pm Fridaypm Friday Winter Winter Precipitation Precipitation expected expected across the across the entire Four entire Four State Region. State Region.
Warning areas Warning areas in blue. in blue.
Advisory areas Advisory areas in purple.in purple.
Temperatures Temperatures Thursday Night - FridayThursday Night - Friday
Lows Highs
ImpactsImpacts 1-3 inches snow/minor 1-3 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>ShrevepTyler>Longview>Shreveport>Magnolia>El Dorado ort>Magnolia>El Dorado and points south.and points south. Will re-evaluate Will re-evaluate
amounts/warnings this amounts/warnings this afternoonafternoon
Lower visibilitiesLower visibilities
Ground temps ~40/35 in Ground temps ~40/35 in AR…precip will stick to AR…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>Natchi>Nacogdoches>Natchitoches-toches->Winnfield>Monroe>C>Winnfield>Monroe>Columbia>Colfax>Jenaolumbia>Colfax>Jena
Over 0.50” would Over 0.50” would cause widespread cause widespread Power outagesPower outages
Instant freeze on all Instant freeze on all surfaces with temps in surfaces with temps in the 20sthe 20s
NEXT CONFERENCE CALL:
Thursday (today) 4 PM Thursday (today) 4 PM www.srh.noaa.gov/shv/briewww.srh.noaa.gov/shv/brie
fingfing
National Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana
