Why Halloween week will be scarily warm

With Halloween days away, a spooky-warm air mass is wafting east, delivering record high temperatures daily through at least the end of the month. Much of the Midwest, southern Plains and areas to the east will face a late-fall wave of warmth as high temperatures range from the 70s near the border with Canada to the 90s in parts of the South.

Hundreds of records for warm mornings are also poised to be set.

The widespread unseasonable warmth is coming on the front end of a highly amplified pattern developing over the Lower 48. With a big dip in the jet stream over the west, and strong high pressure in the east, a big range of conditions is common coast-to-coast.

“Ahead of the front, temperatures will be 20 to 30 degrees above average over parts of the Plains and Mississippi Valley,” the Weather Prediction Center wrote early Monday.

That front will push the core of the warmth somewhat farther east each day before November ushers in a temporary respite.

It will be toasty in the central United States

In the southern and south-central United States, record warmth is a continuation of a well-told tale. The region, as well as the rest of the Lower 48, and areas worldwide, have dealt with a tremendous amount of unusual heat the past two years in particular, a combination of effects from El Niño and climate change.

The temperature reached 100 degrees in Phoenix on Saturday, a record for the date. It was the 143rd triple-digit day of the year; the most the city has had was 145 in 2020.

The ongoing round of records pushed toward Texas on Sunday, with many places from El Paso in the west to Waco in the east setting records.

Monday will be another summerlike day as temperatures rise to the 80s and 90s across Texas, Oklahoma and Kansas. Temperatures could threaten the 90 mark as far north as Salina, Kansas, which is about 25 degrees above normal.

Temperatures over the next few days that could set records include:

• A forecast of 92 in Amarillo, Texas, on Monday; the record is 87.

• A forecast of 80 in Green Bay, Wisconsin, on Tuesday; the record is 77.

• A forecast of 79 in Detroit on Wednesday; the record is 76.

In addition to the summerlike warmth in the southern Plains, a red flag warning is up for a portion of the region. In the event of a wildfire, high winds and dry conditions could lead to rapid growth over coming days.

A flip from chilly to warm in the east

Monday began with much-cooler-than-normal weather in much of the Northeast and mid-Atlantic — the coldest of the season so far. Away from the immediate coast, readings deep into the 30s were common. Higher elevations and farther inland witnessed temperatures into the 20s or even the teens.

The cold air’s time is short.

Through Halloween, there will be a serious surge of warmth. Some moderation begins Monday for highs, then temperatures up to 15 or 20 degrees above normal sweep the Great Lakes and Northeast over the next several days.

In addition to all the daytime warmth, overnight temperatures more common of daytime highs in late October will be felt across portions of the Midwest into New England.

Weirdly warm Halloween in the east

Trick-or-treaters may need to ditch the polar bear costumes to go as a pool lifeguard in parts of the east.

Spots including Philadelphia, D.C. and places southward along the Interstate 95 corridor should see highs around or above 80. From New York City to Boston and inland locations of southern New England, 70s will be most common, though temperatures could also make a run at 80. Even into northern Maine, highs could reach for 70.

Records are forecast for:

• Hartford, Connecticut, with a high of 80.

• Albany, New York, with a high of 79.

• Buffalo, with a high of 75.

• Caribou, Maine, with a high of 70.

It also appears the cold front and chance of showers should hold off until Friday.

What to know about Halloween conditions elsewhere

Warmer-than-normal conditions will be nearly universal east of the Mississippi River into southern Texas. It should be within a few degrees of normal for much of the Plains, trending toward much chillier than normal in the Western United States and intermountain region.

Low pressure moving through the Upper Midwest and Great Lakes will have a trailing cold front moving east of the Mississippi River late in the day and a chance of passing showers or a storm in the Midwest to the South.

Another area of potential precipitation could focus on the Pacific Northwest, where the heaviest rain is likely near the coast and snow is a risk in the mountains.

How long will it last?

While a cold front late in the week is slated to bring temporary relief to the atypical autumn weather in the East, it’s possible the respite will be minor and short-lived. There are strong signs that a similar pattern will quickly reestablish itself and hang on for at least the first week of November.

The best long-range weather modeling suggests this as a likely outcome and so does the Weather Service in its latest outlooks for that time range.