With flurries and clouds moving out into early evening and high pressure nearby tomorrow, our main forecast concern in the week ahead is with a late week system. A potpourri of precipitation types (snow, rain, sleet, and freezing rain) are forecast in the Ohio Valley Thursday night.<\/p>\n

This will be a tricky forecast, especially with a lack of consensus among models. With a lack of consensus, it is not worthwhile to make a specific county-by-county ice accumulation forecast. We are also more than 48 hours out on this event, supporting the idea that now is not the time to go into specifics.<\/p>\n

My focus for this blog post will be on output from the SPC Short Range Ensemble Forecast (SREF) model. The word “ensemble” in meteorology refers to a series of models that are run with different initial conditions; if models with different initial conditions are in good consensus on a particular forecast, confidence is higher than average that particular forecast will verify. Looking at the mean of the SREF models helps to weed out extreme model forecasts.<\/p>\n

This morning’s SPC SREF run gives the Tri-State between a 30% and 90% chance (depending on where you live) of measurable ice accumulation between 10pm Thursday and 1am Friday:<\/p>\n

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This morning’s SPC SREF gives the Tri-State a roughly 40% chance that we get at least 0.05″ of freezing rain accumulation (at least a light glaze) between 10pm Thursday and 1am Friday:<\/p>\n

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NOAA’s Hydrometeorological Prediction Center gives most of the Tri-State a 10% chance of 1\/4″ of ice accumulation or more Thursday night and early Friday:<\/p>\n

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1\/4″ of ice accumulation serves as a rough milestone for where power lines start to sag or may fall completely to the ground. 1\/8″ of ice will lead to some slick roads and sidewalks<\/p>\n

This morning’s GFS model gives Cincinnati about 0.2″ and Wilmington about 0.15″ of ice accumulation Thursday night; likewise, this morning’s NAM model gives Cincinnati about 0.15″ and Wilmington about 0.1″ of ice accumulation Thursday night. Again, these are what two models are projecting and is NOT <\/strong>a forecast. I share these totals with you to show that this is not going to be a major ice event but may be more than a nuisance.<\/p>\n

What To Expect Thursday Night<\/strong><\/p>\n

<\/strong>Confidence is high that sleet, rain, snow, and freezing rain will overspread the Ohio Valley Thursday evening. Precipitation will likely start as a mix of rain, snow, and freezing rain in Cincinnati with temperatures around freezing. Nearing 12am Friday, the mix of snow, rain, and freezing rain will transition to a rain and freezing rain mix…with a small chance for sleet also. By sunrise on Friday, most – if not all – of the Tri-State will see rain with some freezing rain and sleet mixing in north of Cincinnati.<\/p>\n

Right now, I’m thinking some in the Tri-State see a light glaze of ice, especially north of the Ohio River. Temperatures will be in the lower 30s nearing all of Thursday evening; the temperature is forecast rise 1-3\u00b0 between 10pm Thursday and 7am Friday, which works against the idea of ice accumulation.<\/p>\n

A 1-2\u00b0 change in temperatures Thursday night may have a significant impact on what type of precipitation you see and how much ice you see. <\/strong>It is better to start conservative on an ice forecast and ramp up if needed than to go the other way.<\/p>\n

Stay tuned for an update tomorrow!<\/p>\n","protected":false},"excerpt":{"rendered":"

With flurries and clouds moving out into early evening and high pressure nearby tomorrow, our main forecast concern in the week ahead is with a late week system. A potpourri of precipitation types (snow, rain, sleet, and freezing rain) are … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","om_disable_all_campaigns":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[3],"tags":[],"yoast_head":"\n