Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 345 PM EST Sun Feb 09 2020 Valid 00Z Mon Feb 10 2020 - 00Z Thu Feb 13 2020 Days 1-3... ...Southern California to the southern High Plains... A well-defined shortwave digging south across California and the Great Basin will continue to amplify, with a closed low developing over Southern California Sunday evening. Models are in good agreement, showing this system continuing to drop to the south into northern Baja California by late Monday. This will support locally heavy totals across the higher elevations of the San Gabriel, San Bernadino and San Jacinto mountains. As it begins to interact with a northern stream shortwave digging south through the central Rockies, the upper low over the southwest will begin to turn east into northwestern Mexico Monday night. Southwesterly flow ahead of the low will support precipitation spreading across southern and central Arizona, with high elevation snows expected along the Mogollon Rim and White Mountains. Meanwhile, enhanced low level convergence/frontogenesis associated with the northern stream wave will support locally heavy snows moving south through the southern Colorado to the northern New Mexico ranges Monday night into early Tuesday. Areas impacted by the heaviest accumulations are expected to include the San Juan and Sangre de Cristo mountains. By early Tuesday, deepening moisture east of the Rockies will begin to interact with the low-to-mid level baroclinic zone dropping into the Texas Panhandle -- supporting snows spreading east, with the potential for significant amounts developing across the region on Tuesday. Models show the streams continuing to phase and move east, with an open wave trough moving from the southern Rockies to the High Plains on Wednesday. Could see some additional snows developing on the northwest side of a weakening low level wave lifting northeast from West Texas on Wednesday, however thermal profiles appear marginal at this point. ...Northeast... Warm advection precipitation will spread quickly east ahead of fast-moving, weakening low moving across Michigan into eastern Canada Sunday night. Snow, changing to rain is expected across much of Pennsylvania and southern New England by Monday morning, with widespread heavy accumulations not expected. However, enough cold air may remain in place long enough to support at least a few inches of snow - especially across the higher elevations of the Catskills. Low level easterly flow may support some lake-enhanced snowfall totals east of Lake Ontario into the Tug Hill Region. By Monday evening, precipitation is expected to diminish as the low races off to the northeast into the Canadian Maritimes. For Days 1-3, the probability of significant icing (0.25-inch or greater) is less than 10 percent. Pereira