Record warmth is expected this week in Philly. But don’t get used to it.
Philly may have its first four-day run of 70-plus temperatures since October.
Those stray islands of snow are growing ever smaller. The shrinking hills of plowed snow and ice are looking more and more like so much burnt toast.
And almost in sync with the switch to daylight saving time, the atmosphere is about to calendar-jump to May, with a record high in the mid-70s expected Wednesday.
“It’s about time,” said Mike Silva, meteorologist with the National Weather Service in Mount Holly.
“I think people are still recovering from the last heating bills,” he said.
The weather service and AccuWeather Inc. are calling for a high of 76 degrees on Wednesday, which would crest past the record of 74 that was set five years ago. If the forecasts hold, that would mark the first time Philadelphia has reached at least 70 degrees officially on four consecutive days since October.
Is winter over in Philly?
Along with those post-7 p.m. sunsets, the trees are swollen with buds, and the birds are coming back as summer-like high pressure system over the North Atlantic is pumping warm air over the region.
Is winter finally over in Philly? “Ah, no,” said Silva, stopping short of saying cue the laugh track.
A significant cooldown is coming later in the week, and the region could even see some wet snowflakes Thursday afternoon as a potent front crashes through, he said. Thunderstorms are even possible late Wednesday night and early Thursday.
While no significant winter storms are on the horizon, even in computer fantasyland, more winter intrusions are expected before the month ends, said AccuWeather senior meteorologist Chad Merrill.
A few days ago, a dramatic warming in the upper atmosphere over the Arctic — a so-called sudden stratospheric warming event — occurred, Merrill said. That allows cold air to spill southward by weakening the polar vortex, which normally acts like an invisible fencing to keep cold air trapped in the Arctic.
Those effects may not be evident around here until around the spring equinox, which occurs March 20.
NOAA’s Climate Prediction Center two-week outlook issued Monday had chances favoring below-normal temperatures from Sunday through March 23 in Philly and the rest of the Northeast.
The forecast for the week ahead
On the first clear day since March 1, the temperature soared into the mid-70s Monday afternoon, and is expected to head back to the same territory Tuesday and Wednesday.
Philly has its best shot of hitting a record high Wednesday, since the daily records on other days this week are in the 80s. That’s a quirk of the period of record, which dates to 1872. Maybe in 500 years, it will smooth out.
Thursday’s high in the 60s is forecast to occur in the early morning and then fall during the day. Readings won’t get out of the 50s through the weekend.
It should be a robust period for residual melting. As ugly as it may be, the dirt and grime on the snow promote melting.
When the snow gets dirty, said Silva, “It absorbs more sun.”