INDOT Winter Weather Forecasts

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FORECAST UPDATED: 12:00 pm Friday, Jan 30, 2015 by Mike Baldwin (baldwin@purdue.edu)


Summary: Widespread precipitation associated with next winter storm expected to arrive Saturday night. Winter storm system should affect most of state Sunday with significant snowfall accumulations possible. Exact position of rain-snow line continues to be highly uncertain. Windy conditions are expected late Sunday, resulting in blowing snow mostly across the northern portion of the state. Colder air will lock in for the rest of next week.


Conditions on Friday night into Saturday morning are expected to be favorable for minor frost formation, with light winds and partially clear skies through most of the night. The remainder of the daytime hours on Saturday are expected to be dry, with clouds increasing as the moisture associated with the next storm system approaches the state. Our attention turns to the next winter storm. Precipitation with this storm is predicted to enter the state from the southwest during the late afternoon hours, and should spread across most of the state on Saturday night. Temperatures are predicted to remain relatively warm on Saturday night as this precipitation begins, with a rain/snow line predicted to be located somewhere near/north of U.S. 50 during this time. Some of the numerical models have shifted the storm slightly northward in the current forecasts, which would also shift this rain-snow line northward as well. Our forecast map (below) indicates a 30% chance for winter weather mainly across the northern portions of Seymour and Vincennes districts, and the southern counties in Greenfield and Crawfordsville districts, mainly due to the uncertainty associated with the exact position of the rain-snow line. It is quite likely that we will see a transition from rain in the south to a mix of rain and snow in the central areas (southern part of 60% area on our map), to all snow in the northern third of the state (northern 60% into the 90% area). Even in the northern portion of the state, relatively warm low-level temperatures are predicted, which would result in a wet snow condition. By midnight Sunday morning, widespread precipitation is expected to fall across most of the state.

This precipitation is predicted to remain quite steady as we move into Sunday morning and through the daytime hours of Sunday. As the recent numerical forecasts have shifted this storm northward, warmer conditions are predicted as a result. The position of the rain-snow line could also shift northward during the day on Sunday, with some of the model guidance indicating its position moving up to the I-70 corridor during the early afternoon on Sunday. The northward extent of the low-level warm air will have a big influence on the snowfall totals across the central and southern portions of the state. The northern half of the state is currently predicted to remain all snow throughout this event. Relatively warm temperatures will tend to produce wet snow conditions, with some melting on contact during the daytime hours of Sunday in many locations. Given the long duration of snowfall and total precipitation currently predicted, a large area of snowfall accumulations of 8-10” is expected, with maximum accumulations near 12” possible, the maximum snowfall is expected in a region near and north of U.S. 24, mainly north of a Lafayette-Kokomo line. Snowfall totals should drop off fairly rapidly as you move south, due to the relatively warm conditions, obviously depending on the where the rain-snow line ends up. We will update the forecast as newer information arrives and provide a more detailed snowfall map with our updated forecast. Precipitation associated with this storm is predicted to weaken as we get into Sunday evening, with some light wrap-around snowfall possible across the northern half of the state, finally ending at around midnight Monday morning. As the storm intensifies later in the day on Sunday, winds are expected to increase, which should produce blowing snow conditions, especially across the northern ⅓ of the state. These strong winds are predicted to continue into the nighttime hours of Sunday and into Monday morning, which will prolong the impact of this event.

An area of cold high pressure is predicted to move in for Monday, with some light snow possible across the north on Tuesday. A strong cold front is predicted to push through the state on Wednesday, possibly bringing a brief shot of light snowfall across the state. A large area of cold high pressure is predicted to settle into the area for Thursday and Friday, bringing dry conditions and favorable conditions for morning frost accumulation.


Forecast map: (midnight - midnight Saturday Jan 31)

Forecast map: (midnight - midnight Friday Jan 30)



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