Preliminary Iceout Prediction
Conditions are beginning to look favorable for iceout in the Sunday to Tuesday time frame. The ice is now breaking up daily and is about 2 inches thick. It is composed of the late season "candle" crystals that are weakly joined. Within a few hundred feet of its edges, the ice is rolling in the waves rather than holding flat.
A strong late winter blizzard on the great plains is pushing a cold front into the Mississippi River states tonight, a process that is generating severe thunderstorms along the cold front and a change to cold weather behind it. This storm system will track to our west this weekend, initially causing our local wind to increase from the southeast -- a major wave-generating direction for the open lake. The cold front now pushing severe weather through the nation's mid-section will overtake this area on Sunday. It will bring rain, possible thunderstorms, and strong wind gusts to the lake, along with a wind shift into the northwest -- the other major wave-generating direction here.
Along with the cold front there will be rain and possible thunderstorms. The combination of weather conditions will significantly reduce the amount of ice in the lake -- perhaps bringing official iceout. The only factor that will not be present are warm temperatures, or this prediction would express greater confidence. Temperatures may dip into the 20s for the next two nights, and we may see a few more snowflakes this weekend also.
Despite lack of warm temps this year, the ice has weakened thanks to recent rain and dense fog. The weaker ice will clear out very quickly if we get strong enough wind. It is beginning to look like a windy weekend, with wind coming from the lake's two biggest wave-generating directions. If the wind is able to clear the main lake of ice, some patches may remain in the protected bays.
Warmer weather -- near 60 F -- is in the forecast for after Monday. That may be enough to melt any remaining ice.
Official iceout is declared by Emerson Aviation of Laconia Airport, when the M/S Mount Washington can reach all of her ports without hitting any ice. I am forecasting a 75% chance of iceout during or within 48 hours after after this weekend's expected stormy weather, and a 90% chance of iceout within the next 7 days.
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