July 2018 Weather: 4 Things to Watch

July is typically when the hottest temperatures of the year occur for most of the United States, and July 2018 will start off steamy for much of the nation's midsection and East. The focus of the heat, however, is expected to shift westward as the month progresses.

Another thing to watch in the month ahead is an increase in moisture in the Southwest due to the monsoon. Other areas of the country may see drier-than-average conditions, which could lead to drought expansion.

1. Heat Will Be Widespread to Start July

An upper-level ridge of high pressure, or northward bulge of the jet stream, will bring hot and humid conditions from the Plains to the East with temperatures 10 to 20 degrees above average from the Great Lakes into the Northeast.

(MORE: Late June-Early July Heat Wave)

Highs in the 90s will be common here, with some 100s possible, especially in the southern Plains. Highs in the 80s will be found at times across the northern tier, as well as in the South and Northeast coast.

In addition, low temperatures will not provide much relief from the heat. Lows will be mostly in the 70s, with 60s toward the Canadian border.

2. Temperature Shift Ahead

Relief from the heat is expected in the East heading toward the second week of July as the upper-level ridge of high pressure over the East will shift toward the West. This will allow an upper-level trough, or southward dip in the jet stream, to develop over the Northeast.

This will translate into hotter temperatures in the West, but will bring temperatures closer to average for July in parts of the East.

The latest outlook from The Weather Company, an IBM Business, indicates that most of the contiguous U.S. can expect near or warmer-than-average temperatures overall for July, with much-above-average temperatures toward the West Coast.

"We expect a very warm start to July and then a retrogression/pattern flip sometime around mid-month as the atmosphere responds to a combination of emerging El Niño forcing, favorable MJO evolution and very wet recent conditions across the northern U.S.," according to Dr. Todd Crawford, chief meteorologist with The Weather Company.

However, even with the pattern shift expected in mid-July Crawford notes that "we still expect the full-month anomalies to be solidly positive across the northern/eastern U.S., but with clearly dampened magnitudes."

3. Moisture Increases in Southwest

Monsoon season typically kicks into gear in July, and moisture is expected to slowly move into the Southwest later in the first week of July.

The monsoon is caused by the intense heating in the region, which results in a wind shift that brings moisture northward into the Southwest, from southeastern California to eastern Colorado. The monsoon can also bring dust storms, strong winds, floods and dry lightning.

NOAA's precipitation outlook for July indicates a chance for above-average rainfall from Southern California into central New Mexico northward into southern Wyoming in July. An area near the Four Corners has a 50-percent chance of above-average rainfall.

One of the reasons the Southwest could see an active monsoon season over the next few months is that the eastern Pacific has seen above-average activity so far this hurricane season, which can result in more moisture surging into the region. As of June 28, there have already been five named storms in the eastern Pacific Basin.

4. Drier-Than-Average Conditions May Worsen Drought

Three areas of the U.S. might see drier-than-average conditions in July, according to NOAA, due in part to recent trends and guidance from computer models.

One area includes portions of the Northeast, where abnormally dry conditions have recently been observed. An area of moderate drought developed from southern Vermont into southern Maine in late June, according to the latest U.S. Drought Monitor. If July is drier than average, drought concerns will likely grow in the region.

Another area where drier conditions are anticipated is the Northwest, including where moderate drought conditions are present in western Washington and western Oregon.

Portions of southern and eastern Texas into the lower Mississippi Valley may also see a drier-than-average July. Recent rainfall here has improved conditions along the coast, but a dry July would likely bring a return to drought conditions.