BETHLEHEM, Pa. — The meteorological winter of 2022-23 is now in the books as the seventh-warmest on record in the Lehigh Valley.
Based on preliminary numbers from the National Weather Service, the average temperature in Allentown was 35.8 degrees. That was 3.2 degrees above average, but below the warmest winter season on record, which was 36.8 degrees in 2019-2020.
- Meteorological winter has ended and meteorological spring has begun
- The Lehigh Valley's meteorological winter was 3.2 degrees above average
- But winter isn't over yet, with a storm system set to approach the region Friday
Meteorologists use the calendar and annual temperature cycles to break down seasons into three-month periods. In the Northern Hemisphere, meteorological winter begins on the first of December and ends on the last day of February.
But as we move into “spring,” winter isn’t quite over and attention has turned to a significant storm system that will approach from the south and west on Friday.
Guidance early in the week suggested the possibility of wintry precipitation from the storm, but some changes were apparent from the latest overnight guidance.
Here’s how things appear to be shaping up:
Arrival: Models have delayed the onset of precipitation for the Lehigh Valley area, bringing the storm into the region on Friday morning.
The key details: The weather service said we can expect precipitation to begin overspreading the area southwest to north late Friday morning into the afternoon. However, the stronger push of warm air could be more aloft as opposed to at the surface. Thus, we could be a battleground of air masses — setting the stage for a wintry mix of snow and sleet at the onset before a change over to rain.
As details continue to be ironed out, meteorologists say there’s a better chance of a more significant wintry event over the northern part of the region near the I-80 corridor.
“As the primary low [pressure system] moves toward Ohio, a secondary low will eventually take shape near the Delmarva peninsula late day Friday or Friday evening,” the weather service said in its latest forecast discussion.
“Depending on exactly where this sets up, this could help keep cold air in the lowest levels locked in longer over the Poconos and northwest New Jersey.”
Precipitation: Forecasters say the heaviest precipitation with the storm now looks to end up moving through Friday night. As a result, Friday’s high temperature will be reached in the evening.
Most places will see all rain out of this event, especially south of the Lehigh Valley. But in the I-78/I-80 corridor, wintry precipitation likely will continue into Friday night.
In terms of possible snowfall accumulations, the weather service said current thinking is that areas from the I-80 corridor north could see 1 to 2 inches of snow, with areas south seeing less than an inch or no accumulation at all.
“Confidence remains low overall with this, though,” the NWS forecast discussion said.
The bigger threat is the icing potential, as model soundings continue to show what could be a prolonged period of freezing rain, with some spots in the southern Poconos showing significant ice accretion.
In addition to the wintry threat, rain with this system could be an inch to an inch and a half in some spots, resulting in nuisance-type flooding.
