Past IEM Features tagged: temps
Monday turned up the heat a bit more from Sunday with highs into the 90s for most of the state. For Des Moines, the temperature was already 80 degrees at 7 AM. The featured chart displays the hourly frequency of having a 80+ degree temperature for July. The period around sunrise has the lowest frequencies as this tends to be the coolest part of the day and the frequencies peak in the mid afternoon.
Tags: 80 temps
Temperatures soared on Monday with highs exceeding 80 degrees for much of the state. Sioux City was able to reach 90! Strong winds were also present with the very warm temperatures, which as shown by the featured chart is very common when temperatures get this warm in March. The chart shows the frequency of having a 10+ knot wind speed present at a given temperature in March. As temperatures increase, the chance that strong winds are present increases as well. Restating, strong winds are necessary to help produce very warm conditions in March. On the cold end of temperatures, the opposite is true. Brisk winds at night time help to keep the lower atmosphere mixed and near surface air temperatures are not able to cool to very cold levels.
Tags: wind temps
The warm up this weekend was replaced by very cold air on Sunday. After setting a record high temperature on Saturday for Sioux City at 62 degrees, it was -2 less than 24 hours later! The featured chart presents the largest downward temperature swings for the site as recorded by the hourly observations. The only event with a larger change was back in 1982 as the temperature went from 83 down to 18 between 2 and 3 April. Our weather pattern looks to be active this week with numerous chances of snow.
Tags: coldfront temps
Winter made an appearance on Monday in Iowa with rapidly dropping temperatures and a brief dusting of snow causing some travel difficulties. The air temperature for Des Moines at 6 AM was 46 degrees Fahrenheit and by 2 PM was only 28, which makes for an eighteen degree drop. The featured chart presents the weekly frequency of temperature change between 6 AM and 2 PM for Des Moines. For most days, the temperature warms for this period and the most frequent warming occurring during the strong heating of the summer season. Large negative drops, like that on Monday, are relegated to the cold season when fronts are stronger (larger temperature contrasts). Temperatures today will warm from their 6 AM value, but barely warm to just above freezing for some in the state!
On average, the third week of July is the warmest week of the year as shown by the featured chart. The bottom panel shows the number of years since 1879 that the given week was actually the warmest for that year. The warmest week has happened any time during the summer and even into September. The warmest week so far this year was June 18- 25th at just over 78 degrees. The forecast for this week has some warm temperatures included, but does not appear to be warmer than the current warmest for this year.
On Thursday, the temperature at 6 AM was a balmy 31 degrees for Des Moines but then dropped to 18 at noon. The featured chart looks at how common it is for the noon temperature to be colder than the 6 AM temperature for each day of the year. This situation is certainly the most common during the winter months when air masses dominate our temperatures and the sun is the least effective at warming during the daytime. The bottom chart presents the largest difference in temperature between these two hours and for some days in the summer, this situation has yet to happen for Des Moines. Friday will be a different situation with warmer air and sunshine both conspiring to push us to just above freezing!
The record high temperatures on Saturday have given way to much colder temperatures and even some snow on Sunday. The past day and a half has seen a temperature swing of 45-50 degrees. The featured chart presents the maximum computed 12, 24 and 36 hour temperature change based on hourly observations from the Des Moines weather sensor. The temperature swing experienced this past weekend is about typical for an extreme temperature swing this time of year. The largest values on this chart are in the springtime when the contrast in air masses are the strongest. The summertime has the longest values as humidity helps to temper potential temperature swings and artic air masses do not survive the trip south.
Tags: temps swings
Tuesday was yet another spectacular day in Iowa with a warm breeze pushing high temperatures into the 80s for some. It also made the third day in a row that high temperatures were 40+ degrees warmer than the morning low temperature. The featured chart looks at the longest streak of having daily warmups over 40 degrees by month for Ames. Getting a streak of these days looks rare in deed, the October record of 4 looks hard to break today as low temperatures this morning are around 50 instead of in the 30s.
The featured chart shows the frequency of a certain 10 day period of a month being the warmest of that month. Rewording, which 10 day period of a month is usually the warmest. This is based on observations from Ames since 1893. For example, for October the first 10 days are the warmest for roughly 70% of the years. This will appear to be the case for us this year. This chart also shows interesting asymmetry during the spring and fall months.
Tags: climate temps