Beth Hall

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On July 16th, the national Climate Prediction Center released the climate outlooks for August (Figure 1) and the August-September-October (Figure 2) period.  Both outlooks are indicating significant probability for above-normal temperatures.  Precipitation is likely to be above normal for the southern two-thirds of Indiana in August, but there is little-to-no guidance for the 3-month, August-September-October period. Abnormally dry conditions are starting to ease across the state, due to recent rainfall.  However, evapotranspiration has still be relatively high due to the warm temperatures, so dry conditions remain spotty across the state.  Fortunately, temperatures are likely to be below normal through August 7th (Figure 3), which may help lower evapotranspiration rates.  Modified growing degree-day accumulations are very comparable to recent years in the northern part of the state, but are still lagging in the southern half (Figures 4 and 5).

Figure 2. Modified growing degree day accumulations since April 1, 2020.

The roller coaster ride of Indiana weather continues.  Things were drying out across the state with signs of browning lawns, rolling vegetation leaves, and lowering pond and stream levels.  Then the rains came.  Most of the state received between 2 and 3 inches of precipitation from June 20 through 29th – with wetter areas to the south and drier areas to the northeast.  While this may seem good enough to relieve any concerns about drought developing, the temperatures have been high to encourage the evaporation of those wet surfaces.  As a result, the US Drought Monitor has kept most of the state at “Abnormally Dry”.  The climate outlook for July 8-14 shows increased confidence of below-normal precipitation with the possibility of this dryness continuing into mid-July.  Additionally, probabilities are significant that temperatures will be above normal – further exacerbating any dryness due to lack of rainfall.  The climate outlook for[Read More…]

Figure 2. The Evaporative Drought Demand Index (EDDI) representing the level of modeled dryness based on recent precipitation, temperature, humidity, and other evapotranspiration factors. Period covers May 28 through June 11, 2020.

Indiana has been very dry the last several weeks (Figure 1) and conditions are starting to show in lawns and fields.  This dryness has been exacerbated by low humidity and warmer temperatures (Figure 2).  After a nice respite this past weekend, temperatures will start rising again into the weekend, but may not seem too uncomfortable with humidity remaining low at the front end of that warming period.  The short-term forecast is calling for a slight chance of precipitation over the next seven days, but expect it to be light and spotty.  The good news is the climate outlooks for the rest of June is showing increased probabilities of above normal precipitation (Figure 3), … but will it be enough to compensate for the deficit we have been facing these past few weeks?  It is too early to know for sure, but there are no major storm systems on the horizon,[Read More…]

Figure 2. Comparison of accumulated modified growing degree days since April 1 over the past several years.

June Outlook Calling for Above-Normal Temperatures Beth Hall Indiana State Climate Office The month of May was sprinkled with a record-breaking freeze over Mother’s Day weekend, followed by heavy rainfall the following weekend, with a roller coaster of cool periods and extremely warm periods.  We often think of spring as being that transition between winter and summer with lots of ups and downs, but those extremes from one week to the next made it difficult to know what to expect more than a few days out.  By the time the month ended, precipitation was slightly below normal in the southwestern and west-central parts of Indiana with the rest of the state slightly above normal.  May’s temperatures averaged only 1°F to 2°F below normal.  This is a great example of how averaging data can mask the extremes that made up reality! What will June be like?  The latest national Climate Prediction[Read More…]

Figure 2. Seven day precipitation forecast from that National Weather Service representing May 19-26, 2020.

Two weekends ago, Indiana was facing freezing temperatures that broke numerous records across the state.  This past weekend into early this week, the story has been lot of rain.  As of the morning of Tuesday, May 19th, the northwest counties have received over 4 inches with a northwest to southeast gradient of decreasing amounts down to less than an inch along the Ohio boarder (Figure 1).    Will these rains continue?  The current forecasts and outlooks are predicting much less rain across the state over the next seven days (Figure 1) and only weak probabilities of above-normal precipitation into early June (Figure 2). Regarding temperatures, the forecasts suggest normal and above-normal temperatures over the next week with high confidence of above normal temperatures continuing into early June (Figure 2).  This should hopefully help growing degree-day (GDD) accumulations catch up to normal.  To track how GDDs have been accumulating since April 1,[Read More…]

Figure 1. Forecasted minimum temperatures for early morning Saturday, May 9, 2020.

The earth’s position and movement around the sun welcomed the spring equinox on March 19th, and meteorologists in the northern hemisphere welcomed spring on March 1st.  Unfortunately, the atmosphere – particularly over the midwestern and Great Lakes states – refused to acknowledge those dates to offer us a more traditional spring.  Sure, Indiana’s spring 2020 has been drier than 2019.  The compromise to that gift, however, came with periods of below normal temperatures, and potentially below freezing, damaging conditions this Friday across much of state (Figure 1).  This may not even be a one-and-done phenomenon as the National Weather Service is predicting a risk of much below-normal temperatures for the far northern counties in Indiana for May 13-15.  Is Mother Nature aspiring to break low temperature records?  The record latest dates for 32°F or lower minimum temperatures are mostly after May 15th, so we will just have to watch and[Read More…]

1 in 10 years last 28 F is after

The Climate Prediction Center’s outlook for May is dominated by uncertainty regarding both temperature and precipitation (Figure 1).  The computer models could not settle on a consistent pattern for either above- or below-normal temperatures for the month and precipitation outlooks are only slightly confident that there will be above-normal precipitation in southern Indiana.  Shorter-term outlooks through mid-May are predicting increasing confidence for continued below-normal temperatures but very little guidance regarding precipitation. Climatologically speaking, there is less than a 10-percent chance that a hard freeze (at or below 28°F) is still likely to occur aside from the northeastern counties in Indiana (Figure 2).  However, forecasts are predicting above-freezing overnight lows for this region, so the threat of any expansive, hard freeze is minimal. With the recent cold temperatures, modified growing degree-day ( accumulations have slowed.  As of April 20, 2020, GDDs are running 20 to 45 units below normal (Figure 3).[Read More…]

Indiana precipitation

Staying true to global climate trends these days, March 2020 finished warmer and wetter than the 1981-2010 climate normal period.  Snowfall across the state was below normal and localized flooding was a common feature.  There were 3-to-5 more days than average in March where rainfall was observed (Figure 1).  This has led to saturated soils throughout the state and a desperate need for some drying out. Will that happen?  The national Climate Prediction Center is currently sending mixed messages.  The April outlook suggests increased confidence in temperatures being warmer than average and slight confidence that precipitation will be above normal.  However, shorter-range outlooks are suggesting even greater confidence for cooler temperatures throughout the rest of the month with uncertainty about rainfall amounts relative to normal.  A significant cold wave is expected to pass through the state over the next several days into next week.  Overnight lows will be at or[Read More…]

Figure 3. Average date of the last frost with temperatures at or below 28°F.

Over the past 30 days, southern Indiana has received above-average precipitation which has caused some flooding and well-saturated fields.  Northern Indiana has received near-normal precipitation, yet there are localized areas of pooled water.  Snowfall across the state has been below normal throughout the entire season, mostly due to temperatures staying above freezing.  As the dormant season is wrapping up, accumulated chilling hours (35°F-45°F) are well ahead of normal (Figure 1), which is hopefully a good sign for perennials!  Growing degree days (base 50°F) have started to accumulate (Figure 2), which will also encourage plants to start emerging and leafing out.  Unfortunately, Indiana is statistically likely to still experience at least one more hard frost.  The average date of the last frost with temperatures 28°F or lower is between April 3-10 across most of the state (Figure 3). Climate outlooks over the next few weeks are showing increased confidence of above-normal[Read More…]

Map of U.S. indicating 8-14 day temperature outlook

The initial cool wave of September is likely over as we welcome warmer temperatures for the next several weeks. The Climate Prediction Center is showing strong confidence for above-normal temperatures through September 24rd, which should help accumulate growing degree days and move agricultural production further along. Outlooks are showing significant probabilities for above-normal precipitation over the next few weeks, but it is uncertain how much and when that precipitation will occur. The 3-month (September-November) climate outlook is indicating significant probabilities for above-normal temperatures. This will hopefully discourage any cold waves passing through from causing an earlier-than-desired hard freeze event. However, keep in mind that predictions are still too far in the future to provide any certainty and climate outlooks are unable to account for a brief (1-to-3-day) event from passing through with temperatures low enough to cause a frost. Primary message: still too soon to predict when the first fall[Read More…]