Rain, snow today no worry; Monday night nastier
Forecasters don't expect this evening's rain and snow showers to amount to anything. And Sunday looks sunny. But the forecast for the holiday on Monday looks much nastier, with a "wintry mix" promising to mess things up north and west of the urban centers.
"If this were to verify," said Eric the Red, "we'd be looking at a pretty significant winter storm for Monday night into Tues. ... with snow changing to sleet and likely followed by a prolonged period of freezing rain."
The National Weather Service says surface temperatures here on Monday will remain pretty cold as low pressure now organizing over Texas, approaches from the south. That will send warm air from the south rising up and over the colder, denser surface air. That surface layer will be cold enough and deep enough to produce snow at the beginning of the event.
But with time, the cold air will erode, and the snow will start changing to sleet, then freezing rain, especially west of the Blue Ridge and across Northern Maryland. The freezing rain could persist long enough to put a glaze of ice on everything. Please watch your step and be careful on the roads Monday night.
Finally, as the surface air warms, and the southern low moves up the coast, it will become all rain. Tuesday will be rainy, but as the low moves off, the wind will shift to the northwest, colder air will move in and whatever precipitation remains may change to snow before ending.
And then things will shift back to the below-average cold conditions that have prevailed for most of the time since early December, with highs - which average in the low 40s at this time of year in Baltimore - only in the low- to mid-30s.