1:30 PM | **Not quite done with the cold shots in the Mid-Atlantic region and overnight lows in the 30's...they'll continue into at least early May**
Paul Dorian
Another cold air outbreak will reach the Mid-Atlantic/Northeast US by the middle of next week and it will stick around into the subsequent weekend. This loop of 850 mb temperature anomalies comes from the 12Z GFS model runs and extends from Tuesday evening, April 26th to Sunday evening, May 1st. Maps courtesy NOAA, tropicaltidbits.com
Overview
Temperatures could surge to 80 degrees this Sunday in parts of the Mid-Atlantic region, but as has been the case for much of the spring, this next warm up will not necessarily stick around for an extended period. In fact, signs point to another shot of cold air for the Mid-Atlantic region by the middle of next week and teleconnection indices suggest we may have to deal with unusually chilly air masses right into the first part of May with overnight lows in the 30’s.
The second half of this upcoming weekend will see a surge of temperatures to 80+ degrees in much of the Mid-Atlantic’s I-95 corridor, but this kind of warmth will not be sustained. Map courtesy NOAA, tropicaltidbits.com
Details
A warming trend began a couple of days ago in the Mid-Atlantic region and temperatures by tomorrow afternoon are likely to reach the lower 70’s in much of the DC-to-Philly-to-NYC corridor. In fact, after a slight downturn in temperatures on Saturday, there may be quite a surge on Sunday with the 80’s possible in DC and Philly and the upper 70’s in the NYC metro region. As has been the case for much of the spring, however, this late weekend warm up will not signal the end of the cold air outbreaks for the Mid-Atlantic region that have been rather frequent in recent days.
Teleconnection indices of NAO and AO will slide into “negative” territory over the next several days and this usually results in a favorable pattern for the transport of cold air masses from Canada into the central and eastern US. Plots courtesy NOAA
A couple of teleconnection indices that provide information on the North Atlantic and Arctic region are forecasted to move into “negative” territory during the next few days and this often is correlated with cold air outbreaks from Canada that make their way into the central and eastern US. Indeed, a “negative” North Atlantic Oscillation (NAO) and its closely-related cousin, the Arctic Oscillation (AO), will slide into “negative” territory as we head towards the end of April and will stay there into early May. With such a pattern, high-latitude blocking will develop across places like Greenland and northeastern Canada and this, in turn, leads to a more favorable wind flow pattern in the upper atmosphere that can lead to outbreaks of cold air from northern Canada into the eastern half of the nation.
The next shot of colder-than-normal air will likely arrive in the Mid-Atlantic region around Tuesday night of next week and the next couple of days will likely again feature temperatures well below normal for this time of year. After experiencing temperatures potentially at 80+ degrees on Sunday, the Mid-Atlantic region may feature highs confined to the 50’s by the time we get to the middle of next week. Unfortunately, those colder-than-normal conditions are likely to stick around for much of the second half of next week and could very well extend right into the first week of May. Bottom line…enjoy the next few days which will be quite decent and mild.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com