May 2018 was warm and dry
If you blinked, you may have missed spring this year. After winter-like weather lingered deep into April, we saw the weather machine shift gears quickly into a summer-like weather pattern as May began.
Those that are native to the region have seen this before. Chilly air can hang on well into the spring, with the help of the still-cold Gulf of Maine, then when the building warmth to the west and southwest finally gets enough of a push, we see temperatures skyrocket overnight.
After seeing temperatures struggle to reach 70 during the last week of April, we were quickly dealing with readings close to 90 degrees right after we turned the calendar to May.
The first hot weather of any year is always tough to get used to, especially when we see high readings rise almost 40 degrees in three days. The high recorded on May 1 was 52, and by May 3, the recorded high was 89.
May saw the typical roller-coaster type temperature pattern common to our area this time of year, and it was all dependent on the wind direction. When the wind is west or southwest, temperatures bubble up to summer levels, but when any easterly direction develops, we see readings struggle to rise.
It is not at all unusual during May to see temperatures plummet by 30 or more degrees a day after readings are in the 80s. This often happens when a back-door cold front switches the wind to the east off the 50-degree Gulf of Maine. The reverse also occurs on occasion.
During May 2018, we saw prevalence of warmer westerly winds. May’s average temperature measured at the Pennichuck Water Works was the fifth-warmest May out of 125 years of temperature record.
The average reading of 61.5 degrees was 4.8 degrees above normal and was welcomed by outdoor enthusiasts and farmers that had suffered through lingering cold and cloudy weather during April. The gardening season started late, but the May warmth brought the season back in line by the end of the month.
No frost or freezing conditions were noted around the region this year during May. During some May’s, we see frosts well into the month, which keeps most gardeners apprehensive about planting tender plants before Memorial Day.
At the start of May, trees had yet to leave out, but the warmth of the month brought trees to full bloom by month’s end. The process of foliage development uses a great deal of soil moisture, and another aspect of May was the development of dryness.
Rainfall was lacking during May with only some sporadic, mostly light showers a few times during the month. The greatest daily rainfall was 0.80 inches recorded on the morning of May 16. A thunderstorm the previous afternoon provided the rainfall and was the only day with thunder during May, three less than normal.
Lawns remained green for most of the month, but by Memorial Day weekend, we started to see some browning in spots as the high, strong sun depleted soil moisture. The developing dryness showed through the Crop Moisture Index, which was favorably moist to start the month but fell to a slightly negative, dry level by the end of the month.
The drought monitoring index called the Palmer Drought Index also dropped but takes much longer to react to dryness. Dry weather would have to last well into the summer before we would begin to talk about drought, but top soil moisture conditions could become very dry long before a drought even begins.
Rainfall totaled 1.92 inches at Nashua for May, a deficit of 2.15 inches. May was in a tie for 29th driest out of 135 years with rainfall records for Nashua. For the year, the total of 17.28 inches is 2.23 inches behind normal. Nine days saw measurable precipitation during May, three less than normal.
Official spring is defined as the months of March, April and May, when we talk about weather and climate. Spring 2018 was mild, dry and snowy. March and April saw temperatures below normal, but May’s warmth tilted the season to the warm side of normal.
Spring’s average temperature of 46.3 degrees was 0.5 degrees above normal and ranked in a tie as the 39th mildest spring since temperature records began in 1885.
Spring rainfall totaled 10.22 inches, 2.51 inches below normal. March was slightly drier than normal, while April was slightly wetter than normal, offsetting each other. May’s dryness brought the season into the dry category.
Spring 2018 was the 60th driest spring on record for the Gate City out of 135 years with rainfall records. 1983 was the wettest with 20.83 inches.
Snowfall for spring totaled 34.8 inches, 23.3 inches above normal. Spring 2018 was the eighth-snowiest spring on record out of 108 years with snowfall records. The majority of the snow fell during March, which was the fifth-snowiest March on record. April provided a little more to the total with no snow recorded during May.
June brings us the longest days of the year. By months’ end, the days will already be getting shorter. By meteorological definition, official summer began on June 1 with June 21 being the beginning of astronomical summer which has nothing at all to do with weather.
Typical for June around southern New Hampshire are a few hot, humid days mixed with days displaying brilliant blue skies and refreshing temperatures and humidity. Much like June 2017, we have seen some cool, wet weather to begin the month, rain that is beneficial for our vegetation.
Weather & Climate is written by Doug Webster, a Hudson resident and senior meteorologist at
Hometown Forecast Services in Nashua.