Iowa Environmental Mesonet Daily Feature

Lack of cold

akrherz@iastate.edu (Daryl Herzmann)

The featured map displays the percentile values for fall minimum temperature this year compared with all other years for a period up until 24 November. Des Moines has only seen a minimum low of 30 degrees so far this fall, which is easily the warmest minimum for the site. Rewording, every year prior to this one, Des Moines had seen a temperature below 30 during the fall before 24 November. Cold air will arrive in time for Thanksgiving, but lows will only be in the 20s.

7 days around Thanksgiving

akrherz@iastate.edu (Daryl Herzmann)

The featured chart shows the observed frequencies of precipitation for the 7 days around Thanksgiving for Ames. The chart does not indicate any increased observance of precipitation on or near Thanksgiving. The actual forecast for this week has precip chances every day until Friday, with a chance of some snow on Wednesday into Thursday.

Sunny at noon?

akrherz@iastate.edu (Daryl Herzmann)

It seems like we have been stuck with cloudy days for a while now. The featured image attempts to illustrate this by taking a sample of the Ames webcamera imagery at noon each day since the first of August. Clear skies stick out nicely as compared with dreary gray images. The forecast has some hope for seeing some sun this weekend with mild temperataures in the 50s.

Ingesting dry air

akrherz@iastate.edu (Daryl Herzmann)

The featured map is water vapor channel satellite imagery from Wednesday evening showing the impressive size of the slow moving storm system that has brought pesky showers to the southeast half of Iowa. Areas in orange and red indicate dry air aloft and you can see the storm system is now ingesting these pockets of dry air from both the east and west. This dry air has cut down on the amount of rainfall being produced and our system will finally pull away from the state today.

Warmer High Temperature

akrherz@iastate.edu (Daryl Herzmann)

Thanks to a slow moving storm system to our south, places like Lamoni (in Southern Iowa) experienced a cloudy and rainy day while locations farther north like Mason City saw the sun and warmer temperatures. The high temperature in Mason City was 9 degrees warmer than Lamoni. The featured chart looks at the frequency of Mason City having a warmer high temperature than Lamoni (north/south comparison) and also Dubuque having a warmer high than Sioux City (east/west comparison). In November, Mason City is warmer than Lamoni about 10% of the time (think of it as 3 days for the month). The chart shows an interesting annual signal and a probable change in the dominate spatial temperature structure between the summer and wintertime.

Fighting the dry air

akrherz@iastate.edu (Daryl Herzmann)

The storm system to our south continues to slowly churn away and push moisture north into Iowa. The northward advancement of the precipitation has been impeded by a large amount of dry air being pushed into the state on northeasterly winds. The featured map is a combination of wind barbs, relative humidity, and NEXRAD from Monday evening. Notice the blotchy nature of the precipitation shield over unsaturated air and how the NEXRAD presentation changes as the relative humidity approaches 100%.

Near none to four inches

akrherz@iastate.edu (Daryl Herzmann)

The featured map is the five day precipitation forecast from the Hydrometeorological Prediction Center. The forecast has Iowa in a range of near nothing in Northwest Iowa to around four inches in far Southeast. This is all thanks to a very slow moving storm system that will stay just to our south and east. Some snowfall is expected out of this storm system as temperatures will hover very close to freezing.

Higher Percentiles

akrherz@iastate.edu (Daryl Herzmann)

The featured chart displays the daily temperature percentiles for Ames since October 1. Most of November (green highlight) has seen climatologically warmer high temperatures than most all of October. The forecast has us cooling off a bit with highs back in the 40s next week.

Fall Precipitation

akrherz@iastate.edu (Daryl Herzmann)

The featured graphic displays an estimate of statewide averaged rainfall per day since the first of September. The image shows how there was not much of any break in the rainfall during October, while September and November experienced considerable stretches of dry weather. The dry stretch in November looks to be interrupted this weekend with the approach of a couple of storm systems.

Only a little bit of rain

akrherz@iastate.edu (Daryl Herzmann)

Rainfall totals this month look nothing like the October so far with only a few tenths of an inch estimated over parts of the state. The dry weather looks to continue until this weekend with another stretch of dry weather expected next week. This all is great news to farmers still working to get the fall crops harvested.

Good start to November

akrherz@iastate.edu (Daryl Herzmann)

Temperatures so far this month have been on the mild side of averages with this past weekend around 30 degrees above average for high temperatures. The forecast has the mild weather continuing with mostly dry conditions. The path and speed of Tropical Storm Ida is already impacting our weather and will continue to for the rest of the week.

We'll take the 70s

akrherz@iastate.edu (Daryl Herzmann)

Temperatures soared this past weekend into the 70s, which is well above average for this time of year. The weather is exactly what Iowa farmers needed to help get the harvest in. Another week of dry weather appears to be in store this week with high temperatures slightly cooler in the 50s.

Woefully short

akrherz@iastate.edu (Daryl Herzmann)

Outside of a warm week or two this growing season, there was not much heat to speak of and our growing degree total was some 400 units short of average. The record cold in July really hurt as it should be the month where we accumulate the most GDDs. A very wet October did not help the still standing crops any as mold is now a major problem with the corn and soybean crops.

Warnings per month

akrherz@iastate.edu (Daryl Herzmann)

The featured chart displays the monthly number of severe thunderstorm and tornado warnings issued by the National Weather Service for this year and last. In general, the number of warnings is down this year compared with 2008. The most significant difference is the number of tornado warnings in May being half of the total for 2008.

Avoiding Flooding

akrherz@iastate.edu (Daryl Herzmann)

The featured chart is a time series from the Squaw Creek river gauge in Ames for this year. Unlike 2008, Ames has avoiding any major flooding with only a few events of at bank full. The recent heavy rain last week caused the river to rise, but nothing significant for Ames.

Staying above the trend line

akrherz@iastate.edu (Daryl Herzmann)

The featured chart is a comparison of the accumulated rainfall for this year and last along with the climatological accumulation. In general, the running total for this year has remained above the climatology with the heavy rainfall in October pushing us well north of average again. We are still a ways from repeating 2008, which is a good thing.

Record October

akrherz@iastate.edu (Daryl Herzmann)

The big story for October was the record breaking amount of rainfall observed for the month. The featured image is an IEM estimated rainfall percentile showing most of Northern Iowa at 100, which means the highest amount on record. Thankfully, November is starting off mostly dry with only a few light showers expected this week.

Rainy Thursdays

akrherz@iastate.edu (Daryl Herzmann)

The featured chart is the reported daily rainfall from the Ames Airport for October. The month has been extremely wet with now the third day this month with over an inch of rain. This has previously only happened twice before in Ames for October back in 1931 and 1934. There is some hope in the forecast with mostly dry weather expected for the next week.

Too muddy to harvest

akrherz@iastate.edu (Daryl Herzmann)

The feature map is a model's estimate of near surface soil moisture content. Our recent stretch of wet weather has left the top soil saturated with water, which prevents harvest machinery from entering the fields. Rain showers are lingering this morning in Iowa with a better chance of rain expected mid-week.

Rain all day

akrherz@iastate.edu (Daryl Herzmann)

Thursday was pretty much a wash out with it raining nearly the entire day for some locations in Iowa. The featured map is an estimate based on NEXRAD data of the number of hours it rained on Thursday. Rain continues this Friday morning and is expected to clear out by later this evening. The next chances of rain arrive Saturday night and again next Tuesday.