Past Features

This page lists out the IEM Daily Features for a month at a time. Features have been posted on most days since February 2002. List all feature titles.

Features for Nov 2018

Thu Nov 01, 2018
Mild Halloween
01 Nov 2018 05:35 AM
Temperatures for Halloween were mild with highs above the long term average for the date. The featured chart displays the daily high temperatures reported for Des Moines on 31 October. The long term average is shown with the high on Wednesday above five degrees above that level. We look to have another pleasant fall day in store on Thursday before rain moves in for the weekend.
Voting: Good - 7 Bad - 1

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Fri Nov 02, 2018
Two Months in a Row
02 Nov 2018 05:34 AM
Based on unofficial IEM calculations, the northeastern Iowa climate district had its second wettest month on record in a row. The featured chart depicts the highest monthly precipitation totals. Both September and now October rank number one for the area. Thankfully the last portion of October was mostly dry, which helped to allow crop harvest progress and prevent any further flooding. Sadly, this area of the state looks to again be the wettest portion of Iowa over the next week or so. Hopefully rainfall totals do not get out of hand, like they did for the previous months.
Voting: Good - 9 Bad - 2

Tags:   2018  
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Mon Nov 05, 2018
Fall Inch Precip Days
05 Nov 2018 05:35 AM
Many locations in Iowa, like Dubuque, have seen more than its fair share of heavy rainfall events this fall season. The featured chart displays the number of days with at least one inch of precipitation reported for the fall season encompassing September thru November. Dubuque reported an inch on Sunday bringing its season total to six days this season. The long term average is shown and at just two days. The heaviest rainfall this week is forecasted to stay to our south and east.
Voting: Good - 9 Bad - 0

Tags:   fall  
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Tue Nov 06, 2018
Period between High Temps
06 Nov 2018 07:46 AM
The coldest air of the season is being transported into the state and will stick around for a few days with highs in the 30s for most and even colder over northern Iowa. The featured chart looks at the average last fall and first spring days for a given high temperature. For this time of year, we are typically saying goodbye to the upper 60s only to expect to see them again during late March. Charts like these are sort of depressing to realize that the long and cold winter season is just getting started and this week will certainly feel like it.
Voting: Good - 6 Bad - 1

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Wed Nov 07, 2018

View larger image
These are not official Tornado totals, but unfiltered local storm reports.
2018 Tornado Local Storm Reports
07 Nov 2018 05:38 AM
With all of the current election maps showing states in various colors, now is a good time to show one with Iowa in the lead. This map presents an unofficial totaling of unfiltered NWS Local Storm Reports of tornadoes by state. The major caveat here is that these are not official totals of tornadoes. The official tornado totals take a number of months to curate and it may turn out that Iowa has not seen the most tornadoes of any state so far this year. Putting that aside, Iowa has likely seen more tornadoes this year than classic tornado alley states of Kansas, Oklahoma, and Texas.
Voting: Good - 11 Bad - 0

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Thu Nov 08, 2018
Daily Snowfall Frequencies
08 Nov 2018 05:34 AM
Air temperatures have turned rather cold for early November and snow is even in the forecast for today into Friday. The featured chart looks at the observed frequencies of measurable snowfall for Des Moines by day of the year. Having snow during early November is certainly not that exceptional, but not common either with values around one in twenty years (5%). There isn't too much variation during the highest frequency months of December, January, and February with values in the 1 in 4 to 5 years range.
Voting: Good - 6 Bad - 0

Tags:   snow  
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Fri Nov 09, 2018
With and Without Snow Cover
09 Nov 2018 05:34 AM
The presence of snow cover makes a tremendous difference in observed temperatures. The featured chart looks at the average high and low temperature by month partitioned by the presence of snow cover. For November, the difference is a whopping sixteen degrees for high temperature. The snow that is falling today will likely not stick around long, but temperatures will still be quite cold for the coming days. Highs will struggle to reach above freezing even without much snow covering the ground.
Voting: Good - 7 Bad - 0

Tags:   snowcover  
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Sat Nov 10, 2018
'18-'19 Winter Storm #2
10 Nov 2018 11:03 AM
While not much of a winter storm, the light snow was able to accumulate over some portions of the state and bring upwards of two inches to isolated locations. For the purposes of the IEM winter storm accounting, any events like these that get a few reports of at least two inches are counted in the season total. The big story with this event was the bitter cold that settled in afterwards leading to record low temperatures over some locations in the state. We'll have a few more cold days prior to a warm up later in the week.
Voting: Good - 9 Bad - 0

Tags:   winter1819  
Mon Nov 12, 2018
Down to Four Degrees
12 Nov 2018 08:04 AM
Very cold air arrived last week and has mostly stuck around through the weekend. The featured chart highlights the accumulated min low temperature for Primghar (far northwestern Iowa) since 1 July. After having very little cold weather up through most of September, the low temperature reached just four degrees this past weekend. The chart shows the long term average, selected percentiles and range over the period of record. Hitting four degrees this early in November is a bit out of the ordinary for the location, but temperatures has certainly been much colder by now over year's past.
Voting: Good - 2 Bad - 1

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Tue Nov 13, 2018
November Ranges
13 Nov 2018 05:33 AM
The featured chart displays the maximum high, minimum low, and range between those two values for each November back to 1893 for Ames. The long term average is about 60 degrees and this year's range currently stands at 50. So one wonders if we are to expand that range with the days remaining this month, will it be by having a warmer high than 58 or a colder low than 8 degrees? The current forecast is not convincing either way, but there is optimism that the later part of November will be warm.
Voting: Good - 6 Bad - 2

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Wed Nov 14, 2018
Developing El Nino
14 Nov 2018 05:34 AM
The featured chart depicts the combination El Nino 3.4 Index and monthly average temperature departures for Ames. The current forecast by NOAA indicates a 80% chance that an El Nino will form this winter and persist into the spring season. What does that mean for Iowa's upcoming season? Unfortunately, there is no simple relationship whereby you can take the El Nino index and derive the weather for Iowa. The featured chart shows that for the metric of average monthly temperature, it is a mixed bag when the index is not strongly in one direction or another. The most recent "Godzilla El Nino" from 2015 certainly was a driver for a number of consecutive months in a row with above average temperatures, but the current forecasted index is no were near those levels.
Voting: Good - 6 Bad - 1

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Thu Nov 15, 2018
In Memoriam: Dr Ray Arritt
15 Nov 2018 05:34 AM
For over the past ten years, Dr Ray Arritt has administered the Iowa Environmental Mesonet project. I am sorry to share that he suffered a stroke earlier this week and will not survive. He was a wonderful friend, excellent scientist and strong supporter of this project. He was an avid reader of my "Daily Features" posted on this website and would often engage me with questions and ideas. So it seems only fitting to eulogize him with a feature. He did a tremendous amount of work to provide me funding and resources to keep the IEM project going these many years. His guidance will be greatly missed. May he rest in peace.
/s/ daryl herzmann
Voting: Good - 0 Bad - 0
Sun Nov 18, 2018
'18-'19 Winter Storm #3
18 Nov 2018 11:22 AM
The featured map is of snowfall totals from the first snow producing event this weekend between Friday and Saturday morning. The heaviest totals were confined to northeastern Iowa with a few reports over four inches. This map is likely underdone over far southeastern Iowa as it will be difficult to make an analysis there with the snow falling after the morning reporting time and much more snow falling in the location overnight on Saturday. Irregardless, the snow was combined with very cold temperatures and record lows set on Sunday morning.
Voting: Good - 3 Bad - 2

Tags:   winter1819  
Mon Nov 19, 2018
'18-'19 Winter Storm #4
19 Nov 2018 05:34 AM
The snow producing winter storm systems came in rapid succession this past weekend with the first round dropping upwards of four inches over mainly northeastern Iowa and the second round impacting southern Iowa with slightly higher totals. The featured map analysis of available NWS and CoCoRaHS reports is for the second storm. Some of the totals shown in far southeastern Iowa may been a combination of snow from the first storm. All of this snow will likely not survive for Thanksgiving as temperatures are expected to warm.
Voting: Good - 10 Bad - 1

Tags:   winter1819  
Tue Nov 20, 2018
Monthly HDDs
20 Nov 2018 05:34 AM
Chilly weather has been in abundant supply for most of this November. The featured chart presents a heat map of monthly heating degree day (HDD) totals for Ames since 1999. HDDs are a lot like growing degree days and express the departure from a threshold temperature. For this plot, the threshold is 60 degrees Fahrenheit. If one compares the monthly totals between November and December, it becomes obvious that it gets much colder than what we have already experienced. A long winter is yet ahead of us!
Voting: Good - 12 Bad - 3

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Wed Nov 21, 2018
Daily Heating Degree Days
21 Nov 2018 05:27 AM
Yesterday's daily feature looked at monthly accumulations of heating degree days. Today's feature looks at the daily accumulation with the values for this year indicated by dots, the long term mean in red and the range between the 5th and 95th percentile in tan. Our recent cold November weather is shown at the top end of the range, which for heating degree days makes sense. These same values (around 40) are about what is typical for the middle of the winter season. Thankfully and just in time for Thanksgiving, we are expected to have a bit warmer weather before winter cold arrives next week again.
Voting: Good - 5 Bad - 1

Tags:   hdd  
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Thu Nov 22, 2018
Thanksgiving Thanks
22 Nov 2018 06:24 AM
It seems appropriate for the day and with the recent events of the IEM to take a moment to offer thanks. Thanks to our data partners who actively support our data curation efforts and generously share their data with us. Thanks to the ISU Agronomy Department who continues to support the development of this project. Thanks to ISU who provides very stable power, cooling, and plenty of Internet bandwidth to make this project possible. And thanks to you for using our website, sending in bug reports / suggestions, and sharing links to our website with others. Please take a moment today to offer thanks to others and to more appreciate your family and friends.
Voting: Good - 11 Bad - 0
Fri Nov 23, 2018
November Min Wind Chill
23 Nov 2018 06:04 AM
The weather thankfully turned a bit warmer for Thanksgiving and now Black Friday, but a major winter storm is expected for Sunday. After the storm, the temperatures will again be very cold for November next week and we will likely see some bitter wind chills again. The featured chart presents the minimum November wind chill temperature based on hourly reports from Des Moines. This year's value so far of just below zero is about average based on period of record data.
Voting: Good - 14 Bad - 1

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Mon Nov 26, 2018
'18-'19 Winter Storm #5
26 Nov 2018 08:10 AM
The winter storms have been coming quickly this November and the most recent storm was one of the more significant storms for November on record. The snow combined with wind created blizzard conditions over southern Iowa on Sunday, which was very poor timing for folks traveling home after Thanksgiving break. The featured map attempts to depict the extreme cut off between areas that received a foot of snow and those that got none. This border is as tight as 5 miles in some locations.
Voting: Good - 14 Bad - 0

Tags:   winter1819  
Tue Nov 27, 2018
Meeting Blizzard Criteria
27 Nov 2018 05:28 AM
The NWS issues a Blizzard Warning when falling and/or blowing snow combines with strong winds to create dangerously low visibility over at least a three hour period. The threshold for wind is frequent gusts over 30 knots and visibility is frequently less than a quarter mile. The featured chart looks at meeting that criteria based on automated airport weather stations that were under the Blizzard Warning. The three panels uses different methodologies to summarize the best (closest to meeting criteria) values based on wind speed and visibility. The first panel uses a strict requirement on all reported winds and visibility, the second panel takes the three hour average and the third panel uses the median value over the three hour period. Verifying blizzards with automated weather station data is difficult, but so is it for a human as we tend to not want to stay outside for three hour stretches in very bad winter weather.
Voting: Good - 17 Bad - 1

Tags:   blizzard  
Wed Nov 28, 2018
Tough Soybean Harvest
28 Nov 2018 05:35 AM
Getting the agricultural crops harvested this fall has been tough. Snow, cold, and heavy rainfall have made for a limited number of days this season with good harvest conditions. The featured chart depicts USDA NASS soybean crop harvest estimates for Iowa. The white X for each year denotes the location of 98% completion, which is where 2018 currently stands. Only a few years since 1981 show up with a progress slower than this year. The most recent comparable year is 2009.
Voting: Good - 14 Bad - 0

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Thu Nov 29, 2018
Plenty of Early Snowfall
29 Nov 2018 05:31 AM
This past weekend's snow storm was rather exceptional for November. The storm dumped over a foot of snow over parts of southern Iowa and for places like Osceola (south of Des Moines), it pushed the early season snowfall total to the largest on record for the site. The featured chart presents the seasonal snowfall total split on November 28th. Having a large early season total is not necessarily a harbinger of having large amounts of snow for the rest of the season. If anything, the trend is slightly negative. Related: see @climatologist49' s tweet showing before and after November snowfall total correlations.
Voting: Good - 9 Bad - 0

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Fri Nov 30, 2018
Cold November Highs
30 Nov 2018 05:35 AM
A cold and snowy November comes mercifully to an end today, but another winter storm system is arriving today and will bring accumulating snowfall to northern portions of the state. The featured chart looks at the average daily high temperatures for Des Moines for each November on record. This year is shown below 40 degrees and joins only a handful of previous years with such as cold a value. There is some hope for some warmer weather by the second week of December, but the near term cold weather is more definite.
Voting: Good - 14 Bad - 2

Tags:   nov18  
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Features for Nov 2018