El Nino: Impact on Virginia?

In case you missed Zach's El Nino explainer Thursday night, here's the scoop. Impacts on North American weather patterns are mild to non-existent during our Summer and early Fall. However, there have been some indications over the years that during an El Nino event, tropical cyclone activity is suppressed in the Atlantic and Caribbean basins. This is as a result of increased wind shear as you go upward in the atmosphere in the tropics. This shear essentially tears the circulation of a developing cyclone apart, preventing it from "getting its act together."

Once the Northern Hemisphere moves into the Winter months, though, El Nino can have significant impacts on our weather patterns. At this time, it does appear that this newly developed El Nino will last through the end of the year. So what does this mean for Virginia?

Historic El Nino events have meant drier than average precipitation in the Fall in Virginia, and in early Winter, slightly warmer than average temperatures. (Click to enlarge images)


As you go deeper into Winter, there have been cooler temperatures and more snow from December through March in Central Virginia, based on 12 previous moderate El Nino events. So as you can see, El Nino's impacts do depend significantly on the Northern Hemisphere season in which the El Nino occurs.

You can read the entire discussion of the current ENSO analysis here.

El Nino Is Back

It's been roughly three years since we've seen El Nino (a warm ocean current off the western coast of South America). Here are the current water conditions:



Zach will talk about the potential impacts of El Nino for central Virginia during the 6 and 11 PM newscasts this evening. Check it out!

Weather Extremes From Alaska to Texas

Weather in the Commonwealth may be within reason of what is considered average for July (morning lows in the upper 60's, afternoon highs in the mid- to upper-80's), but other parts of the U.S. are experiencing weather extremes, some of which haven't been seen in years. In fact, it's been hotter in Alaska than Virginia this week!

Take a look at the upper level map from Wednesday evening.

Upper-level ridges of high pressure over Alaska and Texas have been leading to record high temperatures this week in both states. In fact on Wednesday, Fairbanks, Alaska set a new record for July 8 of 91 degrees at the Fairbanks International Airport, which was the first time in nearly 15 years that the temperature was 90+! The last time Fairbanks was this hot was August 5, 1994, when the temperature reached 90 degrees. Here are a few other record highs set in Alaska on Wednesday:

Galena 90

Kake 79

Juneau 78

In South Texas, record highs are being set in many cities in the 100's. However, Summer highs like this do occur often in this region, especially in the drier, more desert-like regions of the state. Here's a sample of the new records from yesterday in Texas:

Lubbock 106 (old record from 1998)

Austin 105 (not this hot on July 8 since 1939!)

McAllen 104 (not that impressive, considering they were that hot in 2005 on this date)

Midland 103 (old record from 1998)

Corpus Christi 99 (broke a record from 1947!)

One other weather extreme of note occurred Wednesday in Charleston, SC, where 4.15" fell, breaking the old record for July 8 of 2.84" in 1950. Very heavy thunderstorms moved through the city last night, dumping rain at a rate of nearly 2" per hour. Yowza!

--Carrie