While September marks the start of meteorological autumn, the month featured a few summer – like warm spells at the start of the month and it was not until the second half that Mother Nature showed signs of transitioning to a cooler season. In the precipitation department, September followed suit with the dry trend seen over the summer and the month finished at recording breaking low levels. Parts of New England and the Hudson Valley even entered into a moderate drought. Let’s review September 2014.
For the first 7 days of the month, hot and humid temperatures (more fitting for a week in July) covered the Northeast. Temperatures soared 10 – 15 degrees above average topping out in the 80s and low 90s up and down the I – 95 corridor. On September 2nd, 5th and 6th many reached or surpassed the 90 degree mark. For those in Boston, MA, Hartford, CT, Allentown, PA and Atlantic City, NJ, this warm stretch produced more 90 degrees days than there were in the entire month of August! Precipitation wise, two thunderstorm events occurred during this week. The first was on September 2nd where severe storms brought numerous reports of damaging winds to Maryland and parts of New England. See the video below for a view of a shelf cloud seen in Frederick, MD from these storms.
Later, a strong cold front marched through the region on the 6th. Here, a 58 mph wind gust occurred at Baltimore/Washington International Airport with several additional wind damage reports in central New Jersey, the Hudson Valley and northern Massachusetts.
High pressure then took control briefly on the 7th and 8th before a coastal system moved into the Mid-Atlantic on the 9th. Unfortunately, this system did not bring much needed rainfall into New England. Strong easterly winds, however, cooled the Northeast down 15 – 20 degrees into the 70 – 75 degree range. By the 10th, the coastal system moved offshore with high pressure and 80 degree temperatures returning. Although a cold front approached on the 11th, it came through rather dry, which exasperated the increasing precipitation deficit. The front pushed offshore and stalled on the 12th leaving a gorgeous day for the Northeast; however, a coastal disturbance rode along the boundary on the 13th ushering in widespread showers which produced a few tenths of an inch of rain. Pleasant and fall-like days followed on the 14th and 15th as high temperatures only topped out near 70 degrees. A weak disturbance passed on the 16th and while most only received paltry showers, more substantial rain hit the New York City area where up to 0.50" inches of rain fell.
A very pleasant, yet dry stretch of weather followed for the third week of the month, with seasonable temperatures. This further amplified the growing drought, particularly in New England, where month to date rainfall amounts were below half an inch. By the 21st and 22nd skies became cloudy as a coastal system influenced the region. Although most places just saw minor showers, stronger storms impacted parts of interior New England that dumped over an inch of rain in Hartford, CT and Worcester, MA. After a cold front passed on the 22nd, high pressure took control leaving a seasonable and dry first day of autumn on the 23rd. In addition, the long term deficit in place over New England since early summer finally reached the point where the U.S drought Monitor placed southeast Massachusetts, Rhode Island and eastern Connecticut in a moderate drought. For more information on this drought and how its affecting the fall foliage, see our article.
A strong coastal system arrived late on the 24th into the 25th but again high pressure stayed in place over New England preventing most of the rain from traveling north of New York City. The Mid-Atlantic received the heaviest rain with Atlantic City, NJ, Philadelphia, PA and Baltimore, MD topping out at nearly 1 – 2 inches. Totals decreased heading north due to the high pressure in place. Besides the rain, strong easterly winds brought some minor coastal flooding to the Jersey and Delmarva shores. To illustrate the drastic rainfall total spread between the Mid-Atlantic and New England, see the chart below.
Once the coastal system departed, a gorgeous and summer-like pattern took shape for the final weekend of September. Temperatures soared into the mid 80s breaking record high temperatures in Providence, RI and Newark, NJ at 86 and 87 degrees, respectively, which had stood for over 60 years! By the 29th, yet another coastal system moved up the shore, but substantial dry air prevented much rainfall in the Mid-Atlantic and kept rainfall below a tenth of an inch. The system moved northeast into New England on the 30th where it significantly amplified. In addition, temperatures here turned chilly with highs only reaching the upper 50s to near 60. The disturbance actually stalled over New England and brought consecutive days of rain into the first few days of October. Additional details on this storm will be discussed in next month’s newsletter. Further south and west, temperatures stayed in the mid – upper 70s for the last day of the month.
Overall, the highlight of September 2014 was the significant rainfall deficits. As shown in the graph below, the month finished 2 to 4 inches below normal for nearly everyone north and west of the I - 95 corridor. Places like Groton, CT and Providence, RI which only recorded 0.30 inches and 0.74 inches of rain, respectively, for the entire month rank this as their driest September on record. In addition, both Plymouth and Boston, MA rank it 4th driest in over 50 years of record keeping.
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