A rare (for New England) wind chill watch has been issued for all of New England except for southern Connecticut. While New England sees a wind chill advisory or two a winter, a wind chill warning in this part of the country does not occur very often. While these are still watches, they will likely be upgraded to warnings tomorrow.
There are signals that wind chills could approach -60° in northern Maine. Much of New England will see wind chills approach or exceed -30° on Saturday morning. Wind chills in northern New England are said to be "life threatening" by the National Weather Service. The Gray, Maine office states:
"Potentially life threatening wind chills expected for parts of the forecast area. Timing and magnitude continue to vary slightly run to run...but the main point is that dangerously cold wind chills should cover most if not all of the forecast area at some point during this arctic blast. Also cannot rule out snow squalls along the front itself Thu night."
As stated by the National Weather Service, the exact magnitude of cold air remains uncertain. Yesterday, the National Weather Service stated that this arctic blast is unlikely to reach its full potential as not all of the ingredients were in place for temperatures to drop as far as they could. This is where the uncertainty in coming from. What is certain is that this arctic blast will be the worst in years, and will be dangerous.
The National Weather Service of Boston reiterates the uncertainty, and provides some context for the model discrepancies. They state: (NOTE: ECMWF, GFS and GEFS are weather models)
"There is some uncertainty regarding the magnitude of this arctic airmass as ECMWF more extreme than GFS and basically in historical territory. Interesting that the GEFS mean is 3-5C colder than the deterministic suggesting that GFS may be too warm. ECMWF probably too cold as it is forecasting 850 mb temps as low as -37C (-34F) which is unchartered territory. ...The answer likely lies somewhere in between GFS and ECMWF."
With that said, there has been little change in the forecasted temperatures since yesterday. Here is what is expected and when:
FRIDAY
In northern areas, the front will likely come through overnight Thursday to Friday morning. Stowe, Vermont's high will be a mere -1°. By the evening, the temperature will have fallen to near -10°. The sharp drop in temperatures will be felt region wide. Boston will see a morning high of 30° with temperatures falling to the single digits by the afternoon as the front sweeps through southern New England during the day on Friday. Northern Maine will likely drop below zero Thursday night and stay below zero until Sunday morning.
FRIDAY NIGHT
Temperatures will continue their plummet throughout the night. Lows will likely bottom out in the -10s in much of Massachusetts, except for the coast. Northern New England will see temperatures drop into the -10s to -20s. These are air temperatures. Winds will be very gusty during this time, with 20 to 30mph winds likely throughout the region. This will create wind chills in excess of -20 to -30 in much of the region.
SATURDAY
*LIFE THREATENING WIND CHILLS IN NORTHERN AREAS SATURDAY MORNING*
By early Saturday morning, New England will be firmly in the grips of the arctic air mass. Morning lows will range from the negative single digits south to the -20s north. Wind chills will be in the -20s to -30s in southern New England. In northern New England, the wind chills will truly be dangerous, with lows hitting the -30s to -40s. Mountainous areas and areas north of the mountains will likely see wind chills in the -50s with some models approaching the -60s.
Afternoon highs will not rebound too much. Highs on Saturday will range from the teens south and the single digits, on either side of zero, north. Wind chills will remain well below zero all day across the region.
SATURDAY NIGHT
Temperatures overnight Saturday will be similar to lows seen on Friday night. In some northern areas, the temperature may even get a notch colder than the previous night. The high pressure system will depart on Saturday, but radiational cooling will remain strong and the high pressure's influence will remain in place despite its departure. Winds will begin to back off.
SUNDAY
Despite the day starting off similar to Saturday morning temperature wise, the afternoon will be far different. The temperatures will rise almost as quickly as they fell on Friday. Sunday afternoon highs will be in the 30s for most of the region. In southern New England, highs could even reach the low 40s. This translates to the temperature rising 30 to 40 degrees during the day.
Stay with New England Storm Center for complete coverage of this arctic blast and everything weather in New England.