Graphic courtesy of NWS Buffalo.

ITHACA, N.Y. — There’s no denying it at this point. The days are getting cooler, the nights are getting crisper, and the leaves are just starting to turn if you cast your eyes on the hills. Fall is here. However, the start to October will be a rather warm one, although it also comes with a good chance of rain for most of the week ahead.

Weather Recap

For those of you out and about this past weekend, perhaps at the Apple Harvest Festival downtown or one of the 5K races that frequent the county this time of year, it certainly felt fall-like as temperatures struggled to make it out of the 50s for highs. It was a cool if dry end to what had been a rather wet and stormy week, brought to you by a complex and multi-pronged storm system that ushered in a batch of milder air along with a widespread steady rain, and which was followed by a cold front that set off another round of rain and thunderstorms as well as some flash flood warnings in the already-drenched Southern Tier.

We’ll recap the September weather statistics next week after the Northeast Regional Climate Center finalizes the numbers tomorrow, but suffice it to say, September was a warm and very wet month overall. Initial indications are that October will start off with a very similar pattern, so keep that umbrella handy.

Quantified Precipitation Forecast (QPF) accumulations for October 1-6 2018. Near-stationary fronts will create widespread rains throughout much of the week. Graphic courtesy of the NOAA Weather Prediction Center.

Your Weekly Weather

At the moment, a rather strong area of high pressure has been drawing down cool, dry air from Canada into our region, but things are looking to be quite changeable over the next couple of days. A low pressure area passing through the Great Lakes will bring with it an east-west oriented frontal boundary with warm air behind (south of) it, the edge of a jet stream ridge over the Southeastern United States. The high pressure, now over Eastern Canada, will attempt to push the front back southward, while the low pressure system attempts to drag it northward. What that tug-of-war means is a sizable temperature gradient from Central New York down through Pennsylvania, and some fairly unstable atmospheric conditions, great for the formation of more rain that we don’t need.

Monday’s looking rather dreary as a result. A widespread layer of lower-level clouds will keep skies grey near the front, and it’s likely some rain showers will pass through at times, though they should be fairly light. Temperatures may hit 60 °F in Ithaca city, but the outlying towns can expect to stay in the upper 50s, with slightly cooler temperatures to the north and in the higher elevations. Monday night shouldn’t cool down much as the frontal boundary passes and Tompkins County enters the warm sector around sunset. A few lingering showers will persist under mostly cloudy skies, with lows in the mid to upper 50s; in fact, given our entry into the warm sector, the air temperature will most likely warm slightly after midnight.

Tuesday will be wet and mild. Once the warm air mass enters our region, a south breeze will pick up and raise temperatures into the low to mid 70s by afternoon. But the low pressure area will continue its eastward jaunt from the Great Lakes and the front will be shifted back southward as a cold front, which will fire off widespread rain showers and even a few thunderstorms ahead of its passage. Expect periods of rain by mid-morning, and lasting through the afternoon and evening hours. The warm air mass will be carrying abundant moisture and likely lead to widespread heavy rains 1-1.5″ total, enough that the NOAA Weather Prediction Center, which specializes in hydrology and flooding risk analysis, has indicated a marginal risk for excessive rain and flooding on Tuesday, and with the wind shear and instability in the atmosphere, some strong thunderstorms with gusty winds are possible. Keep an eye out for any flood or severe thunderstorm warnings. The cold front will pass early Tuesday night, and the rain should steadily taper off behind the front, leaving mostly cloudy skies and lows in the upper 50s.

Wednesday should be fairly quiet, there really won’t be much cold air behind Tuesday’s frontal boundary, which will be far enough south to give us a break from the rain. It will be partly cloudy with calm winds and highs in the low 70s. Wednesday night will see a growing southerly breeze and warming temperatures ahead of the next storm system. Yeah, sorry, dig the umbrella back out. Lows will be around 60 °F around midnight, and likely climbing into the low to mid 60s by morning.

Thursday’s storm system bears similarities to the earlier one in that it will also stall out. A Canadian storm system will approach the region from the north, and its associated cold front will swing in from the northwest, run into the ridge of warm air over the Southeast, and slow to a crawl over Pennsylvania. The cold front won’t pass until the early evening, so temperatures should warm up into the mid to upper 70s, but partly cloudy skies will gave way to mostly cloudy conditions and scattered showers during the afternoon. After the front passes, conditions should calm down, with a few showers, partly cloudy skies and lows in the low to mid 50s.

Friday’s looking quiet with dry, partly cloudy skies and highs around 70 °F, and lows Friday night in the mid to upper 50s. However, the models are suggesting the cold front may push back north as warm front, once again continuing the tug-of-war between air masses over our region. It’s like the houseguest that doesn’t know when to leave. The early indications are for an unsettled weekend, bu with temperatures in the mid 70s for highs and upper 50s for lows, so at least it’ll feel comfortable.

Graphic courtesy of the NOAA Climate Prediction Center.

Extended Outlook

For those planning on short and local vacations for the three-day weekend coming up, leave the heavy coats up home, but keep the umbrella on you. Weather models are strongly hinting at a persistent ridge of warm air centered over the Southeastern United States, which will extend over the Northeast for much of the first half of the month. However, areas of low pressure and rain will follow along the edge of the ridge, creating abnormally stormy and wet conditions over the Mississippi River Valley and Western Great Lakes, and depending on the day-to-day movements of the ridge, we may see some enhanced rains as well. Meanwhile, a deep trough out west may bring some of the first snowstorms of the season to parts of the Mountain West – and the staff of the Voice wish former Ithaca Times editor Nick Reynolds the very best with his new job in Casper, Wyoming. Enjoy those <20 °F temps in October, Nick.

Brian Crandall

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