Friday, January 25, 2013

January 27 Severe Ice Storm

A severe ice storm appears to be attempting to set up across the Midwest, Great Lakes and Ohio Valley.

As a storm system begins to approach the region shown above, temperatures will warm to near freezing levels, a perfect scenario for an ice storm. Now, freezing rain is a very tricky precipitation type that commonly comes down to a 'nowcasting' (forecasting as it happens) event, because the environment that supports freezing rain (called ZR in the weather world) is so hard to achieve.

However, recent model forecasts have been in general agreement that an ice storm will hit come Sunday afternoon into evening for the areas in dark purple. These areas could see a severe ice storm with significant travel impacts, as shown below in the Exclusive Impact Scale. I am seeing one forecast for nearly half an inch, one forecast around a quarter of an inch, and another forecast around .15'' in the dark purple areas, so I decided to go to the medium and forecast a fifth of an inch to 4/10th's of an inch, with that plus sign added in the event that half inch forecast verifies. Considering it's an outlier, I'm not that optimistic on amounts really exceeding 0.4''.

Areas in light purple will experience lighter ice accumulations, but still with substantial travel impacts. I expect the Midwest to get the higher end of this 0'' - 0.2'' forecast, with the Ohio Valley getting around the median. But again, it will likely be a nowcasting event.

Here's the Impact Scale forecast:


1 comment:

mike C. said...

Hey Andrew is their a possibility for around the 31st for the east for some snow? I'm seeing the GFS and Euro hinting for something to ride up along the cold front so if it does catch your attention could you let us in on it? Would love that