Severe Thunderstorms, Excessive Rain and Heat Hazards

A Moderate Risk of severe thunderstorms (level 4 of 5) is in the outlook across portions of the Midwest today. Damaging winds, a few tornadoes and frequent lightning with heavy rainfall are in the forecast. Meanwhile, dangerous heat across the southern Plains into the Great Lakes, mid-Atlantic and Northeast will expand into Friday. Risk for wildfires for the central Rockies and Sacramento Valley. Read More >

Monthly Precipitation Anomalies
Figure 3
a)
b)
Fig. 3. Total precipitation deviation from the monthly historical average during (a) El Niño and (b) La Niña events. Composites are made from all the historical El Niño or La Niña events.
Figure 4
a)
b)
Fig. 4. Total precipitation deviation from the monthly historical average during (a) El Niño and (b) La Niña events. Composites are made from all the historical El Niño or La Niña events.
Both Fig. 3 and Fig.4 show the deviation from the monthly total precipitation relative to historical average given in Fig. 2. and Table 1. However, the information in Fig. 3 is in unit of inches, while that in Fig. 4 is presented by percentage.
The monthly total precipitations at all six stations are slightly more than historical average during the El Niño year. However, from January to June of the year after an El Niño event, there is deficient precipitation. The maximum difference could reach as much as 3 inches (around 80%) less than its historical average amount at one station. During a La Niña event, on the other hand, moderate deficient precipitation took place in the first half of the La Niña year. While from October to the end of the next year there is more precipitation. Usually, there is 1-2 inches, or 20-40%, more than the historical average.
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Severe Thunderstorms, Excessive Rain and Heat Hazards

Monthly Precipitation Anomalies

Monthly Precipitation Anomalies

Figure 3

a)

b)

Figure 4

a)

b)

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