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August outlook: We dodge prolonged heat but it’s soggy again

Like July, August is expected to avoid severe, sustained heat and feature abundant rainfall.

Beautiful clouds on Sunday. (Emma K Alexandra)
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Washington had the fortune of avoiding prolonged or record-setting heat in July for a second straight month. That luck looks to hold for August, too, as we project near normal temperatures.

While the heat was somewhat held in check in July, it rained a lot. But the rain tended to come up in bursts and a lot of it fell late in the day or at night, without spoiling too many plans. We expect rainfall patterns may be similar in August.

Our average August rainfall is 3.25 inches, and we are forecasting 3.25 to 6.25 in the month ahead.

For temperatures, the most recent 30-year average is 79.4 degrees (averaged between day and night) and we project an August average temperature between 79 and 80 this year.

The latest simulations from the various weather models (American, European, and Canadian, shown from left to right) support our outlook predicting close to normal temperatures and above normal rainfall for the first half of August:

We’ve managed to avoid sustained heat this summer as the dominating zone of high pressure, colloquially known as heat dome, has resided mostly in the central third of the U.S., from Texas into the Central Plains. We’ve seen it flex eastward at times, but it hasn’t stuck around for long.

Some longer range forecasts suggest that this heat dome could nudge even farther west in the coming weeks, promoting some cooler intervals in the East and increasing the potential for above-normal rainfall.

Here is the outlook for the second half of the month from the National Oceanic and Atmospheric Administration CFS model, which projects near normal temperatures and above-normal precipitation:

July recap: Average temperatures but very wet

August may end up looking very much like July, when temperatures were nearly exactly normal, or 0.1 degrees above the 30-year average of 81.0 degrees.

But what’s normal today was quite hot many decades ago. Dating back to 1872, July 2022 ranks as the 20th warmest on record, tying 1986 and 1872.

We observed our hottest weather on July 23 with a high of 96 degrees. Our lowest temperature was 66 degrees on July 11. We had just one heat wave, which lasted eight days from July 18 to 25.

Rainfall of 7.61 inches was 3.28 inches wetter than normal, the third wettest of the 2000s, and the 13th wettest on record.

Our wettest weather occurred on July 9, when 4.05 inches deluged the District, its 5th wettest July day on record.

How was our forecast for July?

On July 1, we very accurately projected near-normal temperatures. We also correctly predicted above-normal rainfall, but our estimate of 4.5 to 6.5 inches fell short of the actual 7.61. Overall, we grade our outlook for the month an A-.

Year-to-date temperature and precipitation

So far this year, temperatures are running slightly ahead of the 30-year normal and in lockstep with last year. The precipitation total is ahead of both last year and the 30-year norm, but not near record levels.

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