This is the third storm in the past week for our region and poses freezing rain issues rather than snow. Showers are likely to enter the region around sunrise and the main system of rain will arrive around noon and continue for a few hours. There will be cold air in place for many areas and any rain will freeze on contact until temperatures rise above 32 degrees by late morning/early afternoon. This has the potential to be a high impact event during the morning hours if showers do develop into the area before the main event.
General Outlook and Set-up
The same mountains that created the dry slot on Thursday night is shielding the area from rising temperatures, however, overrunning warm air will be circulating around a strong upper-level low today and tomorrow and will be gradually taking over the atmosphere at all heights. Freezing rain accumulations will depend on how stubborn the surface temperatures are at holding their ground. Snow cover along with cold temperatures the past few days will aid in their effort.
Surface temperatures from 5 AM to 1 PM
Below freezing temperatures are plotted to exit the area around noon
Forecast Maps and Timeline
Again, the impact of this event not only depends on how long the temperatures stay below freezing, but more importantly, if showers move in before the main event. This would glaze the area and create treacherous conditions all morning long, not only for a brief period during late morning. The HRRR (High Resolution Rapid Response) model expects there to be a period of rain during the early morning prior to the main event while the NAM (North American Model) misses this intricacy. Both models do plot out the main event similarly with steady rain freezing on contact for northern areas beginning late morning and changing over to pure rain from south to north by noonish.
You can see how the models compare here
Future Radar
Comparing HRRR and NAM future radar at 6 AM and 11 AM
HRRR 6 AM
Freezing rain moving in as early as 6 AM with main event beyond the mountains
NAM 6 AM
No early showers and main event is still beyond the mountains
HRRR 11 AM
Main event moves in, cold air moving out, limited freezing rain
NAM 11 AM
Main event moving in with freezing rain line north of Baltimore and retreating into Pennsylvania
Forecasting freezing rain is always tricky but so important because even a glaze of ice can ruin someone's day. Because this is tricky to forecast, often times I can only get a clear image of how it will play out a few hours ahead of the event after monitoring the radar and temperatures.
As of now, I can say two things
If rain does develop early like the HRRR suggests, there will be widespread icing.
If there is no early morning freezing rain, I expect there to a brief period of freezing rain with small ice accumulations north of Baltimore until temperatures break.
Forecast
It is a safe bet to assume that Frederick and Carroll and Northern Baltimore County will see some freezing rain either from early showers or the main event. I do think there will be light showers before the main event, but I believe most of these will be to the north and west just as the last storm held its initial precipitation north and west. I cannot rule out areas as far south and east as Baltimore to get trace ice accumulations from these early morning showers, but I think temperatures will rise above freezing to eliminate any chance for freezing rain during the main event.
Comments