This weekend has been hot, as we continue this very impressive stretch of 90+ temperatures. Today will feature more heat, as we build toward what may be a record breaking day on Monday and/or Tuesday.
Just as we're watching the heat here, we're watching the tropics, as Hurricane Hanna made landfall in southern Texas yesterday, Hurricane Douglas has the potential to make a rare landfall in Hawaii tomorrow, and we have a 90% chance of development for Invest 92L, which is poised to become Isaias in the open Atlantic.
This seems like a good time to finally talk tropics, so this is a special two part discussion. Part I is on the week ahead. Part II is on tropical tracking and hurricane preparedness. Let's dive in.
Sunday
Today is going to be another hot one. We expect mostly sunny skies and temperatures rising quickly. Highs should top out in the low to mid 90s, just a preview of the next two days. We normally don't talk about low temperatures, but the low temperatures tonight are expected to be warm, so it might be an AC night for most.
Monday
Tomorrow is looking very hot. Again, we are expecting a mostly sunny day, and temperatures will skyrocket on a favorable wind direction for heat. Highs inland, especially in the Connecticut River Valley, will reach the upper 90s and 100 cannot be ruled out. It will also be modestly humid, with dew points in the 60s. That combination will create heat indices over 100 for many.
An Excessive Heat Watch has been issued for Hartford County for Monday. Heat related illness will definitely be possible so watch for the signs. Tomorrow night is looking to be warm as well, with lows in the mid to upper 70s. That doesn't happen here often, which could make Monday a record breaker.
Tuesday and Wednesday look hot as well. Tuesday should be hot and humid, but there will be an advancing cold front. That will bring us the chance of showers and thunderstorms during the afternoon and evening, but right now, those chances do not look particularly high. Some of those storms may be strong to severe, but there's not much of a widespread severe signal. Wednesday will be a move toward less hot conditions, but we're still expecting inland temperatures to reach the low 90s.
Thursday-Sunday
Not much to be said here actually in terms of our weather. Temperatures will be on the gradual decline, but still very warm. The period looks quiet, with no real rain chances, as we possibly turn our attention to the tropics.
The Dailies
Monday: Hazy, Hot, and Humid. Highs in the low to mid 90s at the shore. Highs in the upper 90s to 100 inland.
Tuesday: Partly sunny and hot, with a chance of showers and thunderstorms. Highs in the low to mid 90s at the shore. Highs in the mid to upper 90s inland. Chance of rain 30%.
Wednesday: Mostly sunny and hot. Highs in the upper 80s to low 90s.
Thursday: Mostly sunny. Highs in the mid to upper 80s.
Friday: Mostly sunny. Highs in the mid to upper 80s.
Saturday: Mostly sunny. Highs in the mid 80s.
Sunday: Mostly sunny. Highs in the mid 80s.
Recap of the 2020 Atlantic Hurricane Season So Far
In classic 2020 fashion, this season has been historically active so far. There have been eight named storms. While we have only seen one Hurricane (Hanna), we have seen 4 of the 8 named storms make landfall in the US. Fay, which was a bit of a bust here, brought some relatively light rain and wind to Connecticut after making a landfall in southern New Jersey.
Although we have had a record fast hurricane season so far, some past hurricane seasons, like the benchmark bad season of 2005, had major hurricanes by now. Early season activity doesn't necessarily mean an active season overall, but I expect a very active season for a variety of factors. Although we're approaching August, there is approximately 90% of the season remaining.
Irene was an August storm. Gloria was a September storm. Sandy (which actually doesn't technically count as tropical) was an October storm. The peak of the hurricane season is our peak as well. Below is a NOAA image of the prevailing tracks during each month of the peak.
There is a lot that goes into tracking tropical, but I want to provide a basic overview of real-time tropical tracking. Essentially, you want to watch the development environment and steering environment.
Development environment
The development environment consists of the current factors that will determine how favorable the conditions are for a tropical system to develop and intensify. There are three critical factors: wind shear, moisture, and sea surface temperatures. Wind shear must be low in order for thunderstorms to grow and rotate around the center of low pressure. The less shear, the more organization a tropical system can have. Moisture is critical for thunderstorm formation. With a dry and stable environment, long lasting thunderstorms cannot develop, which aids in developing a tropical system. Sea surface temperatures are critical as well. Temperatures must generally be above 26 degrees C for tropical formation. The higher the temperatures, the greater potential there is for a stronger storm. One thing particularly concerning about this season is the fact that the Atlantic basin is nearly the warmest on record. Even our sea surface temperatures, although below the 26C threshold, are well above normal. That helped Fay in early July. Below are some examples of current conditions.
Steering environment
The steering environment determines where a tropical system is headed. Most storms remain harmlessly out to sea, but sometimes the steering environment is such that the US is threatened. Here, things get a little more complicated than the development environment, but generally, you are looking at the presence of ridges--large scale areas of high pressure that generally keep tropical systems suppressed or on a US coast heading, and troughs--areas of disturbed weather/lower heights that usually push a storm out to sea or in some instances, capture a storm and pull it toward the coast.
In New England, it is difficult to get a tropical system up this way. There is too often troughing that would force a system out to sea well before it reaches our shores. However, New England is not immune to hurricanes. In 1954, New England was hit by two hurricanes. In 1938, New England was hit by our benchmark storm--a major hurricane. In recent memory we have extremely damaging storms like Irene and Sandy, which only brought tropical storm conditions to the state but caused widespread damage.
The fact of the matter is that Connecticut must be prepared for tropical systems each year, even though most years we will see nothing.
We're overdue for a bona fide hurricane strike, but it remains to be seen if such a hit happens this year. A hit is always unlikely, but given the active season and a summer that has strongly favored ridging in areas that historically create a window for northward moving systems, we should be taking additional efforts to be prepared this season.
Tropical Storm Fay brought an early warning. What may become Isaias could be a long track system that gets close to the US coast. We're not even at the peak of the season yet. Should the dominant development and steering pattern continue, I expect additional close calls, more than any year in at least the last few years.
SCW will be here every step of the way, but the message should be clear now: this season we need to be prepared.
Tropical Storm Irene, the last tropical system to most directly impact Connecticut, left more than half the state without power and caused extensive damage along the coast. It was a weakening tropical storm.
Below is an image of the damage in East Haven in the wake of Irene, courtesy of UConn's Center for Land Use Education and Research (CLEAR).
Thank you for reading and trusting SCW.
-DB