More on the Monday System…Latest Thoughts and Forecast Difficulty

February 16th, 2014 at 10:35 am by under Weather

OVERVIEW: Here is a rundown of what we see so far…I caution that this storm is tougher to forecast than Friday’s storm because there will be multiple types of precipitation across different parts of our area.  Trying to exact locations of who will get what will be extremely difficult.  We will carefully examine all new data sets that come in the next 24 hours and make adjustments as needed.  It is safe for all to plan on the possibility of all types of winter precipitation.

AMOUNTS:  This will be the toughest part of the forecast.  Areas along and north of I-70 could see 1″-3″ of snowfall.  Areas closer to I-70 could also see freezing rain and sleet that could add around .1″ of ice accumulation.  Areas to the south of Indianapolis will see lighter snow totals, and more of the rain / freezing rain accumulation.

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TIMING: 

AM COMMUTE: As a leading edge of warmer air arrives, the could be a line of a wintry mix of sleet, freezing rain and snow around the morning commute.  This would be brief, and not cause much accumulation of anything, but may glaze the roads.

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AFTERNOON / EVENING:  The bulk of the precipitation should arrive anytime after noon.  A wintry mix of snow, sleet and freezing rain will hit central Indiana and last through the evening commute, then it should move out of the state by late evening.  The back side of the system may produce some snow for many locations as colder air collapses back into central Indiana.

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IMPACTS:  Roads, especially untreated ones will be slick from either snow cover, ice, or both.  The afternoon and evening commute could be extremely long depending on road conditions.  If the ice accumulation stays low, power outages may be limited.  If for some reason we see close to a .25″ of ice or more, we could have power problems.

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WHY THE FORECAST IS TOUGH:  There will be a warm layer of air that enters into central Indiana.  It will cut-off at some location, and where that cut-off takes place is tough to forecast and is the key to what type of precipitation we will see.  In addition, the air near the ground in most locations is very cold due to significant snow pack.  That influences the temperatures near the ground and keeps it much colder than some models are forecasting because some are not able to factor in snow pack in their models.  There is a high chance that any area that sees rain, could have it freeze on contact, causing a sheet of ice.  Here is a chart that explains how depth of warm air impacts precipitation type.

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Stay with Forecast 8 as we track the difficult winter weather system, as the forecast could change drastically.

 

 

 

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