The featured map displays the number of days since the last Severe Thunderstorm Warning issued by a local NWS Forecast Office. For Iowa, it has been over six months since the last Severe Thunderstorm Warning. This stretch looks to end today with the approach of a strong storm system from our west bringing thunderstorms into Iowa early this evening.

The featured table displays the January thru March maximum dew point as computed over the hourly reported observations. The maximum values this year are some of the lowest on record for sites in Iowa. Des Moines maximum of only 45 degrees was just one degree higher than the lowest values of 44 back in 1956 and 2001. The moist air from the Gulf of Mexico has struggled to reach Iowa this year and that is a big reason for our paltry precipitation totals so far. A cold front is currently sweeping the state and some locations have picked up 0.5 to 1 inch of precipitation.

The featured map presents IEM computed precipitation total ranks for this March. Having a rank of 1 would be the wettest March on record and 123 would be the driest for that climate district. The north to south gradient is very sharp with the boot heel of Missouri having a top ten wettest and southeastern Iowa having a top ten driest March. This analysis indicates north central Nebraska had their driest March on record.

After a chilly Friday, temperatures warmed nicely this past weekend with high temperatures well above average. The featured chart presents the frequency of days for the year to date period that the high temperature was above average. The total this year is close to the long term average of 50%, meaning half of the days this year have had a high temperature above long term average. The year 2012 sticks out in this plot as approximately 80% of the days that year for this year to date period were above average!

Even using a modest threshold of a quarter inch of precipitation over seven days, the featured chart shows very few widespread events over Iowa so far this year. The snowfall of early February is about all there is to show for big precipitation events this year. There is hope that this is about to change this week as a large storm system brings the best rainfall chances we have seen this year. Severe weather also looks likely, but the worst weather will be to our south.

After an extremely quiet March, Iowa's severe weather season is getting ramped up this April with a number of NWS Offices servicing Iowa issuing their first severe thunderstorm warning this year. The featured chart displays the period between the first and last severe thunderstorm warning issued by NWS Des Moines each year. Waiting until April is not out of the ordinary for the first warning to be issued. More warnings are expected today and tomorrow as a large storm system crosses the central US.

The featured chart is an attempt to show a time series of cloud observations from the Des Moines Airport weather station this month. The observations include a base cloud level and the amount of clouds at that level. Once the sensor finds a level that is overcast, it can not sense any further levels above that level. The chart shows that clouds have been persistent for the past three days with the past two having very dreary low clouds. Thunderstorms are likely today, but the forecast has hope that the sun will be visible tomorrow!

It was a crazy day of weather in Iowa on Thursday. Tornadoes, highs near 80, highs near 40, large hail, fog, wind, and snow all happened somewhere in the state! The featured map is an attempted analysis of Local Storm Reports and COOP reports of snowfall. The snowfall reports are problematic as much of it already melted over night and so the reports this morning may have missed some of the totals that did fall.

The featured chart displays to date accumulated precipitation departures over three different windows of time for statewide precipitation estimates. There is currently a large difference between the 30 and 90 to 365 day departures. The wet summer period of last year has the 365 day departure near positive 10 inches while the near term windows are slightly negative. This is the complex nature of drought as departures and surpluses can simultaneously exist.

CoCoRaHS is a volunteer network of people making daily rain, snow, and hail reports. The project was recently in the news as the White House signed up to be an observation site. Iowa has participated in the project since 1 August 2007 and the featured map displays the number of observers per county that have made at least one report in the past year. Not all counties currently have an active observer, so please consider signing up if you are interested!

The featured chart displays the Iowa areal averaged precipitation totals for April. The vast majority of recent years has seen above long term average precipitation for the month. The total so far this year is on track to exceed three inches as well, but forecasted amounts do not look all that extreme for the next seven days. The featured chart a few days back noted that we are currently running a deficit for near term departures, so we certainly do need another wet April to get us ready for the growing season.

Cold weather has been difficult to come by this month with only a few days reaching temperatures below freezing for Ames. The features chart displays the number of days each April that the daily low temperature was below freezing. Of course, there are still plenty of days to go for this April and the forecast keeps temperatures above freezing until at least early next week.

For NWS Forecast Offices that serve Iowa, only Davenport has issued a tornado warning this year. The featured chart presents the period between the first and last tornado warning issued each year by the Des Moines Office. The year 2012 shows up as quite the outlier on this plot with no warnings after the first part of May for the rest of that year. Making it through the end of April with a warning is not uncommon as six years and the past two have done just that since 1986.

The featured map presents precipitation estimates from this past weekend. Much of the state is analyzed over an inch, but extreme northwest and southeastern Iowa missed out. This rainfall was certainly welcome as we have recently been on the dry side of average. Cooler temperatures are forecasted this week and not much for more precipitation is expected.

50 degrees is an important threshold for soil temperatures when it comes to planting corn in Iowa. The featured chart displays the daily four inch depth temperature range from the Ames Ag Farm site. The warm weather last week has given way to much cooler temperatures this week and soil temperatures have dipped back below 50 degrees. The forecast for this week keeps high air temperatures in the 50s with cool overnight lows, so soil temperatures will not warm in this environment.

The featured map displays the last date previous to today that an ASOS/AWOS observation site has reported a sub freezing temperature. For most of the state, we have gone 2-3 weeks without freezing temperatures. This streak has ended this morning for much of northern Iowa as chilly air settled in. It will be another chilly night today and cool temperatures will stick around into the weekend.

The past three days have been plenty windy as strong northwest flow has persisted. The featured chart presents the daily average wind speed and direction for Des Moines Airport this month. Winds during the daytime are much stronger than at night as the sun promotes lower atmosphere mixing during the day, which brings higher speed air down to the ground where we live! The climatology for April is around 10-11 MPH, so this year is not much windier than average.

The featured chart displays the climatology of year to date warmest temperature along with this years result for Ames. The low 80s we saw in mid March has yet to be topped since. It will likely take another week before we even get back to 70 as indicated by the current forecast. The corn planting season, which got off to a torrid pace has now slowed just as quickly with wet and cool conditions prevailing.

The featured map presents the number of consecutive days that the daily high temperature is either above or below average. Below average streaks are represented as negative numbers for this map. Our recent pattern has seen the warm air confined to the extreme southern portion of the US. Some locations in Florida have been above average nearly every day this month so far! Much of Iowa is currently working on a 7-8 day stretch of colder than average weather, but the forecast has hope for warmer weather this week with a return of the 70s to the state!

After a week of cold and wet conditions, this week is going to be just what farmers need with warm and dry conditions prevailing. The featured map presents forecasted precipitation totals thru Saturday evening from the Weather Prediction Center. Totals shown only approach a tenth of an inch over extreme western Iowa. This should allow for significant progress to be made with corn planting this week.

Cold soil temperatures and wet conditions have delayed corn planting in Iowa as shown by the recent USDA crop progress report. The featured map displays the estimated percentage of corn acres planted by state along with the departure from long term average. The weather this week will make a very large change to this map when the updated crop progress report is made next week.

The featured chart presents the daily high temperature departures from long term average for Ames. As like most every year, this year has seen its ups and downs. We are currently working on a few consecuative days of warmer than average weather. The chart shows the periodicity of having warmer than and then colder than stretches of weather. Our day to day weather is dominated by the passing of air masses, which take multiple days to move over Iowa.