Drought Update

The National Drought Mitigation Center released a new update to its drought monitor, and things do not look so good for lots of New England.

(National Drought Mitigation Center)

Parts of Massachusetts, Maine, Rhode Island, and Connecticut all now have an "Extreme Drought", and drought conditions only seem to be accelerating. All of New England is now "Abnormally Dry" with increasingly sever conditions present as you head east. This drought can be attributed to how dry it has been, and to get a sense of the dryness, take a look at these maps:

Total precipitation percentiles for past 3 months (Southeast Regional Climate Centers)

The above map shows percentiles for total precipitation from June 25th to September 25 this summer. Anywhere you see a "1", it has been the driest Jun 25 - Sep 25 on record. It is very apparent that the furthest east parts of New England have been the most dry.

We can take a look at a similar map for the past mont (Aug 25 - Sep 25) and see that it has been exceptionally dry during the late summer to early fall period.

Total precipitation percentiles for past month (Southeast Regional Climate Centers)

We need rain badly, and it looks like drought conditions are set to subside slightly here in the northeast. Here is a look at the Climate Prediction Center's seasonal drought outlook for the period through December 31st.

Seasonal Drought Outlook (NOAA)

In New England, it looks like most areas will either see drought removal or a persisting, but improving, drought. This is on contrast to much of the southwest, where drought conditions will persist or even worsen in some spots.

Warm stretch, some moisture next week, and another cool down to start October

After a few days of below normal temperatures throughout New England, we transition back to warmer weather for the start of astronomical fall. This map shows the mean temperature departure from normal for the past week - notice how almost everywhere in the Northeast had mean temperatures greater than 5 °F below average for the last week.

Mean temperature departure from normal (Southeast Regional Climate Perspectives)

Those cool temperatures and early season freezes will abate over the next few days, as seasonable weather looks to close out the week, and warmer than average temperatures make their return for the weekend. Here is a GIF of the GFS 2-m temperature output, showing temperatures climbing to the upper 70s and low 80s over the weekend. 

GFS 2-m temperatures through Sunday (Tropical Tidbits)

As models have trended warmer over the past few days, it definitely would not shock me if some areas saw temperatures in the mid 80s this weekend. As high pressure builds in the region, the dry spell will continue through the end of the weekend at least. During the Monday to Tuesday timeframe, the combination of some tropical moisture and a dipping jet stream may bring some much needed rain to our region.

After that, I see a big cooling trend for the start of October. Here is the GFS temperature departure from normal at 850 mb in the atmosphere, showing much below normal temperatures for much of the east around the October 3rd timeframe.

(Tropical Tidbits)

The Climate Prediction Center (CPC) agrees, sharing a high probability of below normal temperatures for most of the east except Maine in its 8-14 day outlook. 

8-14 day temperature outlook (NOAA/CPC)

Enjoy this weekend's warm weather while it lasts, as we'll return to cooler weather by the start of the next month!

Autumnal equinox musings

This post will be a short one, covering the autumnal equinox, which officially happens tomorrow at 9:30 a.m.

(National Weather Service)

The autumnal equinox, which occurs between September 22 and 23 each year, marks the day when neither the northern hemisphere nor the southern hemisphere is tilted towards the sun. On this day, both hemispheres receive equal amounts of sunlight - 12 hours (this is not totally accurate, as there are some technicalities here). 

Here in Middlebury, VT, the sun will rise at 6:40 a.m. tomorrow and set at 6:49 p.m. Here's where the technicality comes in - the sun officially rises when the first part of the circle is visible over the horizon, and it sets when the last part can no longer be seen, thus causing us to have 12 hours and 9 minutes of sunlight tomorrow. The center of the sun will be visible for exactly 12 hours tomorrow.

For many, the autumnal equinox is the official end of summer, and the days really start to get shorter over the next few months. Just one month from now, the sun will rise at 7:15 a.m. and set at 5:58 p.m.

I enjoyed my last morning of astronomical summer today by catching the sunrise atop the Middlebury College Snow Bowl - a great way to start my week!

Cold weekend

Happy Saturday! It's a chilly start this morning with temperatures around 30 °F throughout the North Country. For September 19th, we typically see a low temperature of 50 °F, so we're starting the day about 20 °F below normal. We saw the first frost of the season here in Middlebury, VT this morning.

For today, expect temperatures in the mid to upper 50s, with calm winds and sunny skies. High pressure remains draped over our region, providing us with the nice fall-like weather.

HRRR 2-m temperatures for this afternoon (Tropical Tidbits)

I'd imagine that areas will see freeze warnings and frost advisories overnight as temperatures again dip into the upper 20s in some areas. This temperature anomaly map shows just how cool temperatures are for this time of year.

NAM 850 hPa Temperature anomaly (Tropical Tidbits)

The area of high pressure is located where you see all the purple on the above map, giving us our cool temperatures this weekend. It'll simply be a fantastic, but cool, fall weekend, so enjoy it!

Why your phone weather app is no good

In much of New England, we saw hazy skies today as a result of smoke that has moved eastward from the western wildfires. Today would have been a completely sunny day, but sunshine did not really present itself. In fact, some could describe today as cloudy.

At mid-day, my phone weather app looked like this, indicating abundant sunshine.

However, when I went outside and took a photo of the sky, it looked like this:

While the sun is there, the haze and smoke that enveloped us today is very apparent. Why is there the disconnect between the weather app and what the sky actually looked like? The answer lies in the algorithms that the weather app uses. The app essentially uses an algorithm that is based on operational weather models in order to spit out its forecasts. However. the operational models don't account for smoke. Thus, the weather app does not know that their is smoke in the air, and it thinks that it is sunny. That is why we need real human being meteorologists.

One thing that was quite beautiful tonight was the sunset over the Adirondack mountains:

Frost advisories for tonight

Good morning! Get ready for our coldest night since mid-May, as temperatures will dip into the 20s in some mountainous areas.

NWS Advisories as of 9/14 (NWS)

A freeze warning is in effect for the Northeast Kingdom, while many northern parts in the state are under a frost advisory.

Tonight's temperatures also show a good lesson in model variations - particularly in resolutions of various models. First, the NAM that resolves at 12 km shows the area of blue (temperatures in the 20s) in western New York.

NAM 12 km 2-m temperatures (Tropical Tidbits)

However, when we look at the 3 km resolution NAM that operates at a much higher resolution, we can see that the model truly highlights areas that will see the coldest temperatures tonight, showing smaller patches of blue in western New York and some of Vermont, New Hampshire, and Maine.

NAM 3 km 2-m temperatures (Tropical Tidbits)

If you want to take a look at more mesoscale or localized weather processes, it is best to look at models with higher resolutions. However, if you want longer-term forecasting, lower resolution models will be better to use.

Weekend Forecast

Good morning!

Temperatures currently sit in the 30s and 40s throughout the region, making it the coldest morning since early June! This weekend will be a tale of two different weather stories, so I'll walk you through it.

Saturday

Today will simply be a spectacular fall day in the North Country! Temperatures will approach 70 °F, and there will be abundant sunshine.

NAM 2-m temperatures for 4 p.m. (Tropical Tidbits)

If you're planning outdoor activities this weekend, today is the day for them!

Sunday

For tomorrow we'll see a cold front approaching from our west with high pressure exiting to the east, bringing with gusty winds and rain.

(NWS)

Models have been backing off slightly with the rain and trending towards a later onset (as the GFS shows), but I'd still expect some showers in the afternoon with gustier winds.

Sunday p.m. GFS (Tropical Tidbits)

This will be the first true fall-like weekend in the North Country. Today will feature a crisp morning that warms up and brings us plenty of sunshine, while tomorrow will be cloudy, windy, and bring some rain. Enjoy your weekend!