While many are just thawing out from this past weekend's snow and frigid temperatures, local emergency managements officials said Monday to enjoy the next couple of days as thing will change later this week with an ice storm.
Based on the National Weather Service briefing Monday, Shawnee Emergency Management Director Don Lynch on Monday this area should prepare for an ice storm this Friday and into Saturday.
He said winter storm forecasting is much more tricky than severe thunderstorm forecasting because of the specific variability factors including, timing, temperature at various heights in the atmosphere and the amount of available moisture. Forecasters said 30 miles one way or another can mean a big difference in the type and amount of precipitation received on the ground.
Friday morning is when the forecast becomes tricky, he said, as the two big question marks for precipitation type are the strength of the warm air and the depth and strength of the boundary layer airmass.
Currently, NWS computer models predict strong warm air advection, resulting in liquid precipitation aloft. Forecasting the near surface temperatures remains a big challenge. The 32 degree line nearly bisects Oklahoma from the northeast to the southwest through the course of Friday and Saturday, wavering at times as far south as the Red River into north Texas and lifting northward into southeastern Kansas.
Once again, given this variability and the advanced timeframe being several days out, he said, areas of a rain/freezing rain mix should be expected on Friday and Saturday. Sleet production will be difficult with the initial precipitation Friday through early Saturday as the cold air aloft remains shallow enough to be insufficient for refreezing/flash freezing. As colder air begins to slowly spread in from the north Saturday afternoon into Sunday, the chances for sleet and snow increase on the tail end of the system as it lifts out Sunday.
Another concern, is the liquid precipitation amounts expected with this system. Precipitation amounts (liquid) are forecast to range anywhere from a half inch in the west and northwest to 4 inches in south central and southeastern Oklahoma. This is concerning considering freezing rain is expected as a dominant precipitation type at times during this event.
Overall, Lynch said while some specific questions remain unanswered, freezing rain is more than likely and it could cause significant ice accumulations for some locations in Oklahoma. Where this occurs all depends on where the freezing line sets up, he said, which is very difficult to lock down at this time.
Residents should stay aware, check local weather reports at the National Weather Service homepage frequently.