When will the brutal heat wave end? Here’s what to know about the forecast.
Even as the heat dome begins to wane, portions of 20 states from the Ohio Valley to the Deep South and the Carolinas to southern New England remained under heat alerts Wednesday. Temperatures in the 90s to around 100 blanket the region.
A combination of a cold front pressing south through the Great Lakes and New England and the waning intensity of the eastern heat dome will somewhat shrink the area of scorching conditions. But the population under heat alerts is still quite large: 125 million people from the Mississippi Valley to the East Coast.
Over the next several days, the number of areas facing the worst of this wave will diminish on both sides of the Appalachians, but typical summertime heat is expected to persist into next week until a stronger cold front arrives.
Heading into next week and beyond, the worst of the heat is expected more in states in the south-central and western contiguous United States.
Large sections of the eastern half of the country still face a Level 4 out of 4 extreme heat risk, including significant swaths of the Ohio Valley and the Mid-Atlantic.
High temperatures in these areas are expected to reach the mid-90s to around 100 in most locations Wednesday afternoon, which is about 10 to 15 degrees above average.
But by Thursday, the heat dome of high pressure that has been centered near the Mid-Atlantic will become less distinct, and its core will return closer to its typical home in the Southeast U.S.
Much of the Midwest and parts of the Mid-Atlantic will remain under major to extreme heat risk.
Then Friday, the most intense heat will be centered on the Ohio Valley before more typical – but still hot – summertime conditions take over.
There will be major relief for some spots that have recently broiled. For others, not so much. Here’s what six cities can expect in the days ahead.
• Boston: Around 90 degrees on Wednesday afternoon, down from a June record of 102, reached Tuesday. Turning much cooler Wednesday night and Thursday, with highs only around 70. On Friday, maybe only in the 60s, with a few showers. In the 70s again this weekend.
• New York: Ranging across the 90s on Wednesday, from the upper 90s in adjacent New Jersey to the low 90s northeast of the city. Shower and storm chances Wednesday night and Thursday as daytime temperatures dip into the 70s, remain there Friday. Back into 80s for the weekend.
• Washington: Upper 90s to around 100 on Wednesday, with mid-90s on Thursday and an increased chance of showers or storms. Heat index about 10 degrees hotter. In the 80s on Friday before near or above 90 returns for the weekend.
• Raleigh, North Carolina: Near-record highs of 100 or above on Wednesday and in the upper 90s on Thursday. Heat indexes are around 110 on both days, with perhaps a small reprieve Friday. Mid- and upper 90s are likely for the weekend. Any storms will tend to be isolated.
• Columbus, Ohio: Mid-90s on Wednesday, with the heat index near 105. Temperatures somewhat down Thursday and Friday, with increased storm chances, but still at least in the low 90s. Readings may rise again this weekend.
• Nashville, Tennessee: Mainly sunny Wednesday and Thursday, with highs around 100 on both afternoons and a heat index near 110. Mid-to upper 90s should persist through the weekend despite increased odds of scattered storms.
Numerous June records on Tuesday
As warned by forecasts, 100-degree temperature readings were widespread Tuesday.
In addition to the June top mark in Boston of 102, the high there was only 2 degrees off its record of 104.
The temperature in Newark, New Jersey, reached 103. In downtown Baltimore, a somewhat questionable reading of 105 was observed. The temperature at John F. Kennedy International Airport in New York hit 102. All of these are top marks for June.
Every state in New England hit record highs for the month, as did New York state and Maryland.
Locations unusually far north recorded extreme values. It was 102 in North Hartland, in central Vermont, a record for June in that state. Maine and New Hampshire also reached the century mark, with 100 in several locations for the former and 102 for the latter.
At least 600 records for high temperatures and 1,200 for warm lows were set over the past week ending Tuesday, according to NOAA data.
It appears the highest temperatures will migrate west heading through next week and perhaps beyond. An overall summery pattern – given that it is almost July, it’s not unexpected – looks likely for the Lower 48 in the foreseeable future.
The center of the heat dome may end up pushing toward the south-central U.S. and, ultimately, toward the Four Corners of the Southwest. This could mean somewhat less intense weather on the East Coast, bouts of extreme heat across the Western U.S. to the southern Plains and an increase in monsoonal moisture into the arid Southwest.