3,000 Low Temp Records Set This July!

[briann]

http://www.accuweather.com/mt-news-blogs.asp?blog=weathermatrix&partner=&pgUrl=/mtweb/content/weathermatrix/archives/2009/07/1000_low_temp_records_set_this_july.asp



ORIGINAL ENTRY: Here are some stats and maps regarding the unusually cold July that is happening over a large portion of the U.S., especially the Northeast quadrant (yes, it's been unusually hot in the SW, see below). Note: Since I am on vacation at the end of the month, I will not be able to update these but AccuWeather.com will be running news articles about how cool July was in these areas, come the first week in August.

First, some stats. 1,044 daily record low temperatures have been broken this month nationwide according to NCDC -- count record "low highs" and the number increases to 2,925, surely to pass 3,000 before the end of the month. Some thoughts on the 'low highs" below.*

graph of low lows and low highs for July

The period of July 17-20 was the worst, with over 1,600 stations breaking records. It's worth noting that these stats include all records across the nation. Of the record lows, through July 20th (thanks to William Schmitz @ SERCC, check out their Twitter Feed), this was the regional breakdown:

Nationwide: 966
Southeast (AL/GA/FL/NC/SC/VA): 248
Northeast (MD/DE/PA/NJ/NY/CT/RI/MA/NH/VT/ME): 193

Next, a map of the Departure from Average temperatures so far in July (yes, we have one week left). Yes, that's a "-10.0" in Pennsylvania - double digit deficits over a month are rare indeed. Note that there are no positive numbers.

Even if you zoom out to the U.S. you'll see the majority of stations are reporting departures below normal thus far -- only Arizona, New Mexico and Texas have all stations reporting above normal.

The lowest temperatures of the month are also impressive, with 50s in every state and 40s in most, some 30s. Normally temperatures are peaking in July.

And finally I'll repeat this map which shows the lack of 85-degree days in the Northeast through July 20th. Note that the Northern Plains are not immune from the chilly weather either; Mark Vogan says that Minneapolis hasn't failed to hit 90 in the last 15 years. (Mark has some other good stats too).

*I was especially impressed by the latter stat and I think it speaks more to the cool summer people have been experiencing - more people are out and about during the peak of the day then they are early in the morning, so they see that the temperatures in the middle of the afternoon are much lower than they should be this time of year. For perception, this may be even more important than morning lows.


UPDATE: It's not just the surface land temps -- Blog reader Tim points out "Water temps at Frying Pan Shoals (off Cape Fear) fell to 78 degrees a few days ago; NDBC historical data shows this occurs only 0.3% of the time in July!" Here's a look at the weekly departure from normal sea-surface temperatures:

This is not the case away from the Carolina coast; most of the Atlantic that we would be concerned with for Hurricane season is normal or slightly above normal - there are other factors keeping that activity down.