ITHACA, N.Y. — The peak conditions for bringing out fall foliage colors call for a relatively dry period with warm days and cool nights. You’ll have one of the three this week, which probably doesn’t bode well for spectacular autumn displays later this month as we approach the local peak. On the bright side, you can keep the summer clothes out for a little while longer.

Graphic courtesy of the Northeast Regional Climate Center.

Weather Recap

September 2021 will go down in the meteorological record books as a warm and wet month in Tompkins County. According to the Northeast Regional Climate Center, The average temperature clocked in at 62.3°F, 2.1°F above normal for the month. The lows overnight tended to be more anomalously warm (+2.8°F) than the daytime highs (+1.4°F), which is in indication of enhanced cloud cover and humidity, because high humidity doesn’t allow air to cool off as much or as quickly. 62.3°F was good enough for 39th warmest in Ithaca’s 129 years of valid September records.

Regionally, many areas were more anomalously warm. Of the 35 first-order weather stations in the Northeast and Mid-Atlantic, 34 had warmer-than-normal Septembers (the outlier being Beckley, West Virginia). Thirteen of those had a “Top 10” warmest September, with Boston recording its second-warmest September on record, and Newark its fourth-warmest.

Graphic courtesy of the Northeast Regional Climate Center.

On the precipitation side, the Dryden Game Farm Road station recorded 5.23″, well above the normal of 3.83″ and 16th wettest in the 129 years of local records. However, that pales in comparison to certain parts of the Northeast ad Mid-Atlantic that were walloped by the remnants of Hurricane Ida. Newark reported its wettest September on record, with 10.50″ of rain, and Scranton and Bridgeport recorded their second-wettest Septembers on record. Most of that rain fell on the 1st and 2nd, with catastrophic results. However, for much of Upstate New York and Vermont, away from Ida’s remnants, the month was actually drier than normal.

We’ll be continuing September warm and wet trend for the next several days as a storm system falls apart over the region and warm air from the south and southwest is ushered into the Southern Tier. It’ll make for a rather mild and humid week for this late in the year, though it’s better than an early onset of the frozen alternative.

Your Weekly Weather

Several waves of light to moderate rain showers are traversing across Upstate New York this afternoon, part of a slow-moving warm front associated with an area of low pressure centered over the Western Great Lakes. The cells over Tompkins County have been on the heavier side, with about a half inch of rain recorded so far today.

With the continued unstable atmosphere, rounds of rain are expected throughout the remainder of Sunday and through the overnight hours, with light southerly winds, overcast skies and periods of light to moderate rain. Highs in the upper 60s will slowly fall back into the low 60s by Monday morning, New rainfall amounts between now and tomorrow morning will be between one-quarter and one-half of an inch. Training, where storm cells follow in the same path like cars of a train, is possible during the overnight hours, so keep an eye out for flood advisories.

Conditions remain unsettled Monday as the front stalls our along the Thruway corridor and the parent low degenerates into a shortwave of moisture and instability. The atmosphere will have enough energy for some thunderstorms to develop, though nothing severe is anticipated. Some fog is possible in the usual valley locations during the morning, but otherwise it will be an overcast day with periods of light to moderate rain and highs in the low 70s. New rainfall amounts will be between one-tenth and one-quarter of an inch. Monday night will see the showers wind down as the bulk of moisture shifts eastward. Lows will be in the low 60s with overcast skies.

A high pressure system will begin to build in from the north Tuesday, and the air it will channel in its clockwise circulation will largely come from the east, in effect the same warm, moist plume responsible for Sunday and Monday’s rain. The airmass will be more stable, and any rain will be of the late-day pop-up variety. It will be a touch on the humid side with mostly cloudy skies and highs in the lower 70s. The high will remain in place overnight Tuesday, and skies will be mostly cloudy if dry with lows in the low 60s.

Wednesday offers some improvement as the high slides southeastward. That will add a more southerly component to this side of its clockwise circulation, and temperatures will climb into the mid 70s with mostly cloudy skies. Wednesday night will be mostly cloudy with lows in the low 60s, those warm overnights a product of the moist airmass and inability of the air to cool off with so much moisture in the atmospheric column.

Thursday will be another quiet day as the high lingers to the east while precipitation begins to build northward on its western flank and closer to the Southern Tier, part of a cutoff low pressure system (cutoff meaning it’s not flowing with the westerly current of the jet stream) over the Lower Mississippi River Valley. However, it should remain dry during the daytime hours, with mostly cloudy skies and highs in the mid 70s. Skies remain mostly cloudy overnight Thursday into Friday, with some rain showers possible after midnight. Lows will be around 60°F.

Friday will see that cutoff low from the southwest inch closer, and that will bring the threat of rain throughout the day, though it will not be constant, nor will it be heavy. Skies will be mostly cloudy with highs in the mid 70s. Friday night will be mostly cloudy with a chance for showers and lows around 60°F.

Next weekend is looking mild. Saturday will see a chance for showers, but Sunday is looking dry, with partly cloudy skies. Temperatures are expected to top out in the mid 70s both days, about 15°F above normal, with lows in the upper 50s.

Images courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking into mid-October, temperatures are expected to remain above normal as a ridge in the jet stream pumps warmer air into the Great Lakes and Northeast at the expense of a trough upstream bringing colder-than-normal conditions to the Pacific Northwest (on the bright side, the enhanced cold and stormy condition will help quash some of the remaining wildfires). Locally, precipitation is expected to be near-normal to a little drier-than-normal mid-month.

Brian Crandall

Brian Crandall reports on housing and development for the Ithaca Voice. He can be reached at bcrandall@ithacavoice.com.