Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 414 PM EDT Sat Apr 5 2025 Valid 00Z Sun Apr 06 2025 - 00Z Wed Apr 09 2025 ...Southern Plains... Day 1... A 700mb low over the TX Panhandle will slowly track ENE to southern MO through Monday. Ongoing snow over the southern TX Panhandle and just south will continue through this evening with 0.5"/hr rates continuing. A half inch accumulation is likely in southwest OK this evening. Though thermals become increasingly marginal to the ENE over OK and southwest MO, some snow should fall along that path, especially in and stronger bands where accumulation is possible. the day. WSSI remains moderate for a spot between Amarillo and Lubbock for the ongoing snow bands. ...Northern New England... Day 1... Warm air advection precip that develops into a wintry mix this afternoon will persist through tonight over northern New England. High pressure centered over the Gulf of St. Lawrence will keep enough cold air in place to allow pockets of freezing rain and 0.1 to 0.2" ice accretion in the White Mtns and western Maine. Day 1 probabilities for >0.1" ice accretion after 00Z is 20-60% in these areas with moderate impacts per the WSSI. ...Northern Michigan into northwest Wisconsin... Day 2... A vigorous mid-level trough axis shifts southeast over Lake Superior Sunday evening and the rest of MI through Monday morning with surface low pressure development over Lake Huron. A few narrow bands of moderate-to-locally heavy snow will shift over the U.P. and far northern WI Sunday evening before tracking over the northern L.P. late Sunday night into Monday. Post frontal flow will allow some transient LES bands to briefly develop off Lakes Superior and northern Michigan. Day 2 snow probs for >4" are 20-50% over the U.P. and far northern/northeastern WI, and 30-60% over the northern L.P. with 40% probs for >6" from Alpena to Gaylord. ...Interior Northeast into Northern Ohio Valley... Day 3... The low will continue to deepen as it tracks east over the St. Lawrence Monday night through Tuesday. A frontal band of rain that looks to change to snow should accompany the front over the eastern Great Lakes region up through northern NY/New England Monday evening. Too soon to declare this snow squalls, but that threat will need to be monitored, especially as the wind flow increases around the developing low. Lake and terrain enhanced snow follows the front with Day 3 snow probs for >4" 40-70% over the Tug Hill, northwestern Adirondacks, Greens, Whites, and western Maine with 30% probs for >8" on the higher points of that terrain. ...Cascades... Day 3... A pair of shortwave troughs shed from a Gulf of Alaska low approach the PacNW, bringing prolonged precip that starts tonight along the PacNW coast. Snow levels on the Cascades rise above 8000ft by precip onset and persist there through Sunday. The axis of the second shortwave trough crosses the PacNW Monday into Tuesday. Associated height falls allow snow levels to reach 5000ft on Monday, then drop further to 3500 to 4000 ft Monday night through Tuesday. Light to moderate precip during the lowest snow levels should allow some accumulation on the higher passes. Day 3 snow probabilities for >4" are 10-20% at Snoqualmie Pass and 50-80% in the higher WA/OR Cascades. Jackson