Browse Month

July 2011

MD/DC/VA bake in record heat as severe storms form up north

DCA has already gotten to 102 twice today… shattering the daily record of 99 set back in 1993. One more degree would make it DCA’s hottest day of 2011, with three 102 highs already on the board.

IAD is up to 101, breaking its daily record of 97 (also set in 1993) and BWI is at 100, beating the old record high of 99 that was set back in 1954.


Further north, severe weather is the main concern of the day. A Severe Thunderstorm Watch is up for the eastern two-thirds of PA, most of NJ and southern NY. Wind damage will be the main threat, with an isolated tornado or two also possible.


DC region official highs: DCA 104, IAD 103, BWI 101.

Also, multiple tornado warnings have been issued with two cells… one in NE PA near the PA/NY border and one in SE NY heading towards NYC and Long Island.

New Twitter Feed!

After some playing around with Twitter’s widget options, I got something that I’m reasonably satisfied with on the top of the sidebar where the old What To Watch Fore(cast) highlights went. Since I update that more often, I figured it would be good to 1) finally put the feed on the page, and 2) get some fresh content onto the site.

Don’t forget to follow me! @MADUSWX

Highs in the 90s start tomorrow, with storm chances Tue-Wed

Today might get to 90, but the real story lies in the next seven days, where highs are expected to reach from the lower 90s to lower 100s Monday through next Sunday (and beyond?). Thursday through Saturday has been fairly consistent in being the hottest days, with highs in the 97-103 range. The forecast hasn’t been changing all that much, so confidence is high that we’ll see some very hot temperatures at the end of the week. Lows will typically be in the mid 70s during this period.

A weak cold front will provide the region with a chance of showers and thunderstorms Tuesday and Wednesday before the big ridge builds in. There will still be a slight chance of showers and storms through the end of the week, but the next “good chance” for rain will be around Monday of next week.

The First Annual American Weather Conference is being held in Baltimore, MD this weekend… it’s going to be a bit uncomfortable with all that heat! I’ll be in attendance for most of Friday (after noon) and all of Saturday.

Enjoy the cooler temps… they’re only temporary

DCA is sitting at +4.0 through the first 12 days of July, with all but two of those days with highs of 91-97. Today was another warm day as temperatures climbed to about 93 before the storms hit.

Tomorrow through Sunday looks to be more seasonal to even slightly below normal, with highs in the mid to upper 80s. While not necessarily cool, it’s certainly a nice period of relief, especially considering what lies ahead.

Another warm up is on the way during the second half of next week, when highs could climb into the 95-105 range (according to the latest model runs and trends). Whether these hot temperatures will verify or not remains speculative since it is still in the medium range, but all of the medium-range signals point to hot, hot, hot weather next week.

More heat, with normal temps later this week?

I ask the question because, as we have seen in the medium range over the last 45 days or so, we just keep getting the heat due to the impressive sub-tropical ridge. I wouldn’t be surprised if we trend warmer as the end of the week gets closer. On top of highs in the lower 90s both yesterday and today (yeah, we’re at 89 as of this post, but you can’t tell me we aren’t going to get to at least 91), we’ll be looking at 90s Monday through Wednesday.

We should see some of the more impressive heat of the summer early this week, with highs in the mid 90s tomorrow and highs in the mid/upper 90s Tuesday (barring no crazy amounts of clouds/rain). Wednesday may also hit the 90s before cooling back into the seasonal mid to upper 80s for the rest of the week. Again, we’ll see if that forecast holds, but it could be warmer than that.

Right now DCA is sitting at +3.3 for the month (using the old 30-year average… not the new normals that got released at the start of the month), and it looks like we shouldn’t see anything less than a +2 anomaly by the end of the month. It’s another hot summer… stay cool.

Strong storms roll through MD, DC, VA

Strong to severe storms pushed NW to SE across the region this afternoon and early evening, which are now mostly south of the DC area. Didn’t get hit by too much in Germantown, but the lightning was great. Plenty of CGs all around, despite my bad luck of getting good screen captures off of the video I took (I don’t have any filters for taking pictures, so I had to result to video).

I did manage to get one CG shot this afternoon as I sat in light rain behind the main rain cores:

Finally, a storm that I was awake for! Some storms rolled through early this morning, but I was way too gone to get up for them. The last two storms before this morning also had unfortunate timing, so it was a treat to actually get out and catch this storm.

So what’s on tap for July?

Waaaaaaay back in February, I made this little number for July:

EDIT: And here’s the updated look for this month:

It looks to be a decent forecast going ahead, with warm adjustments likely needed in the South, Southeast, southern Midwest and southern Mid-Atlantic. The combination of a lingering upper-level ridge and extreme drought conditions in the South/Southeast are the two main attributors to the need for warm changes.

Looking back at the controversial 2010 analog, it did well in capturing some of the extreme heat areas of 2011. However, much cooler temperatures were found in the West and Northeast in 2011 compared to 2010, and obviously the above-normal extremes were not as high as 2010 in most areas. Most of these differences can be accounted for by the strong -AO/-NAO combination we had in 2011, whereas 2010’s AO/NAO values were close to normal overall. When 2010 is coupled with some of the ENSO analogs (strong NiƱa in the winter that weakened to neutral conditions in the early summer) and drought is accounted for, the June 2011 map appears.

For the Mid-Atlantic, July should be another warm month as the teleconnections seem to indicate a similar pattern to June in the eastern U.S., yielding temperatures of around 2.5-3.5 degrees above normal. So long as we see a continued -AO/-NAO/-PNA pattern to go along with the more long term -PDO/+AMO signals, we should see similar anomalies appear in July.

As for the rest of the country, one of the bigger risks is going to be where the upper-level ridge settles once we head into the middle of the month. We’re already seeing hints of the ridge wanting to move either into the mid-country or into the West going into this weekend. Should the ridge linger out west, it would cause the Northern Plains to be warmer than my July forecast and/or could make the mountain West warmer than expected.