Updates to Hurricane Sandy

During the overnight hours Hurricane Sandy actually strengthened.  For the better part of the past few days Hurricane Sandy remained steady with maximum sustained winds of about 75 mph with gusts in the 85-90 mph range.  As Hurricane Sandy continued to move in a NE direction she went over the warm waters of the Gulf Stream and with this she strengthened.  Hurricane Aircraft hunters have found that maximum sustained winds have increased to 85 mph with wind gusts as high as 105-110 mph and a central pressure of 946mb which ties the record for lowest pressure recorded north of Cape Hatteras, NC and when all said and done Sandy will be the Queen in this regards.  With this let's get right into the specifics...

Coastal Flooding/Beach Erosion  

It's now becoming more likely that the coastline of central/northern NJ northward into the lowest suburbs of NYC to the south facing shore of Long Island to western coastal CT will experience catastrophic storm surge of record levels and extremely damaging coastal flooding.  This will be a life threatening situation to anyone who was told to evacuate who chose not to.  Any buildings right along the water are likely to experience extreme damage or complete destruction.  Elsewhere across coastal CT/RI/E MA/NH/ME significant coastal flooding/storm surge is expected and will also pose a threat to property on the water front.  If you know anyone in an area which was told to evacuate and chose not to get the word to them to evacuate before it's too late and time is basically running out for them to do so safely.

Damaging Winds  

We are looking at widespread damaging winds all the way from NJ up to the US/Canadian Border.  We will be looking at widespread damaging winds lasting as long as 24-36 hours which will lead to widespread tree/power line damage and widespread power outages, potentially lasting for several days in the hardest hit spots.  The strongest wind gusts are expected to occur across the CT coast/RI coast/SE MA where winds could gust as high as 75-85 mph.  Here, during the peak sustained winds could be in the 45-55 mph range.

Rain/Flood Threat

We aren't looking at much in the way of rainfall as the bulk of the rain will be off to our west and southwest.  With that said we could see some spots pick up 1-2'' of rainfall with some isolated amounts of 3-4''.  With this the flooding threat will be real low, however, areas along rivers/streams/brooks may experience some flooding and especially the typical flood prone areas.

Thunderstorm/Tornado Threat

Typically with landfalling tropical system you induce the threat for isolated tornadoes.  While that potential did look extremely low leading up to the event, there have been some changes which have lead to a slight increase in the potential.  Later on this afternoon we will be experiencing some cold air advection in the mid-levels of the atmosphere along with increasing temps/dewpoints in the lower levels of the atmosphere...this will lead to a slight increase in instability and with that we can't rule out the potential for low topped t'storms and given the very strong wind shear there is a low threat for an isolated tornado.  If we are to get t'storms they will have the potential to mix down much stronger winds locally as well.  This potential will have to be CLOSELY watched.

Breaks/Peaks of Sun

There will be a dry slot moving into the region later on...with this dry slot comes the potential for some breaks or peak of sunshine.  If you happen to witness any sunshine today DO NOT let that get your guard down.  Any sunshine will only INCREASE the damaging wind potential and the winds we experience.  The sun would warm the atmosphere enhancing mixing allowing for much stronger winds to mix down.  If this occurs we could locally increase the gusts by as much as 10 to even 20 mph.

Below are graphics of all the mentioned threats:

Coastal Flooding/Storm Surge

Damaging Winds

T'storm/tornado threat

Update on Hurricane Sandy impacts

Latest computer model data continues to indicate the much of NJ/NYC/LI/CT/RI/SE MA will see the most extreme impacts from Hurricane Sandy when taking into account coastal flooding and damaging wind potential.  When looking at rainfall/flash flooding associated with the rainfall that threat will exist more to our southwest/west, however, we will still deal with some isolated flash flooding here.  Given latest guidance here are the hazards at hand:

Coastal Flooding/Beach Erosion

We are looking at major to perhaps catastrophic coastal flooding/beach erosion.  While significant coastal flooding will occur from the Jersey shore following the coastline up through southern ME the potential for catastrophic flooding looks to exist from the lower suburbs of NYC extending into western areas of Long Island South along coastal CT as well as the south shore of Long Island sound.  For these mentioned areas the difference between significant coastal flooding/beach erosion occurring and catastrophic coastal flooding/beach erosion occurring will all depend on exactly when Sandy makes landfall.  The National Hurricane Center is forecasting Sandy to make landfall around 2:00 AM in central NJ, however, some latest models are actually speeding up the timing of Sandy meaning she could make landfall several hours earlier than that.  Forecasted high tides tomorrow night are around midnight, meaning if we see a landfall closer to the high tides that will be the worst case scenario in terms of coastal flooding/beach erosion as we'd be looking about storm surge as high as 10-12'...which would be record and historic levels.  A landfall hours several hours earlier would likely result in storm surge being a few feet less which would probably negate catastrophic type of damage.  Either way you slice it, the coast is in for bad times.  Looking at substantial damage and/or complete destruction to any buildings along the shore along with significant flooding damage.  For anyone who has decided to disobey evacuations in areas ordered to do so this will be a life threatening situation.  

Damaging Winds

Pretty much all of New England is forecasted to experience widespread damaging winds from Sandy as well will be located in the portion of the storm with the strongest winds. As of now it appears the strongest sustained winds will be across southern CT/RI/SE MA where sustained winds during the height of the storm will be as strong as 45-55 mph with wind gusts as high as 65-75 mph.  Even coastal NH/ME could experience similar conditions.  Elsewhere across CT/MA up through MA and into central VT/NH during the height of the storm winds will be sustained between 35-45 mph with wind gusts as high as 55-65 mph.  Across central/northern VT/NH extending into southern ME during the height of the storm wind will be sustained between 25-35 mph with wind gusts as high as 50-60 mph.  It should be noted that if Sandy ends up making landfall further north than forecasted (which is still certainly possible) we could increase these winds by as much as 10-20 mph, especially across CT/RI/SE MA.  Not only will we be dealing with winds of this magnitude but the duration of the damaging winds will be very, very long.  In fact, we could be dealing with damaging winds for as long as 24-36 hours.  In the end this will lead to widespread wind damage with downed trees/power poles/power lines and widespread power outages.  For the areas that get hit hard power outages of at least 3-4 days could be expected.

Rainfall/Flood threat

While the heaviest and most extreme rainfall totals and flooding will occur well to our west/southwest where as much as 5-10'' of rainfall could occur rainfall/flooding is not expected to be a major issues here, in fact, rainfall totals aren't expected to exceed 4'' and totals this high should be more if an isolated occurrence.  Given this flooding will not be a widespread issue, however, can't rule out some isolated flooding, especially areas near rivers/streams/brooks or the typical flood prone areas.

We are already beginning to see impacts from the storm with increased waves/surf and winds have been slowly increasing as well.  As we work through the evening/overnight conditions will deteriorate very rapidly as winds will begin to vastly increase.  We will be impacted through Tuesday, however, by then the winds will have subsided as Sandy will be weakening over land but we can't rule out on and off showers.  This is a very dangerous storm with impacts to life and property and everyone should have taken the appropriate measures.

Below is a graphic:

Historic Storm in Sandy to impact the Northeast

Before we get into the gist of things I would like to begin by saying while we have expectations for Sandy and expecting extreme impacts in the end we just really don't know what will happen.  What is going on right now is in uncharted territory.  Sandy, being a tropical system is defined as a warm-core system, this means that as you move closer to the center of the storm the temperatures increase.  Typically, as tropical systems gain latitude and approach our neck of the woods they begin to transition form being a warm-core system to more of a cold-core system.  This just means that as you draw closer to the center of the system temperatures no longer increase but begin to decrease.  Some tropical computer models have actually been suggesting that Sandy may actually remain a warm-core system much further north than usual and the transition process will be slower than what we typically see.  This alone actually isn't really uncharted, however, when you take into account the developing trough to our west and it's interaction with Sandy this is where we get into the uncharted territory.

We see troughs phase with systems moving up the coast several times throughout the year, however, we have never really seen such a deep trough associated with the Polar Jet phase with a warm-core system...once this phasing takes place Sandy will actually begin moving either due west towards the US coast or moving towards the US Coast in a more northwesterly direction...this is uncharted.  This phasing will rapidly intensify Sandy to become a MONSTER storm and lead to the build up of incredibly high waves, possibly as high as 25-35' crashing into the coast line from southern NJ up through eastern southern New England.

With this said, with what computer models are showing and with what we understand about meteorology and how the atmosphere we would expected to see some extremely damaging impacts from Sandy for much of the region.  Because we really have nothing to compare this too this does make it difficult to really have a true understanding of how this will unfold.  Now that this was said let's get down and dirty.

As mentioned above, Sandy which is a very large in size will eventually be tugged in west towards the coast by a deepening trough associated with the Polar Jet and phase.  Once this phasing occurs Sandy will undergo what is called rapid bombogenesis...this is just a fancy word for saying she will rapidly intensify.  As Sandy continues to grow in size and phase with the trough/Polar Jet the wind fields just above the surface will expand, this will mean winds just above the surface will be very strong and for a quite a distance away from the storm's center.  In fact, computer models are generating wind speeds of anywhere from 60 knots to as much as 100 knots as close as 2000-3000ft above the surface!  This is absolutely remarkable to see winds of that caliber so close to the surface.  With Sandy increasing in size and very strong winds over the ocean wave heights will rapidly build.  As Sandy continues to close in on land very high waves will begin crashing into much of the eastern sea board from the Carolina's to the outer Cape.  This system will also be loaded with moisture so there will be some extremely heavy rainfall as well.

The one question we are still faced with is where Sandy will make landfall.  We are still uncertain as to exactly where Sandy will make landfall.  Some computer guidance suggests she will make landfall around southern NJ/DE area while other computer models suggest she will make landfall further northward...around northern NJ or perhaps even near NYC.  While the first mentioned scenario would still probably bring major impacts to the entire region the second scenario would bring extreme issues to the region.  While the computer models are giving us uncertainties within the track based on the pattern setup along with other factors I would think we see a landfall closer to the northern NJ/NYC solution meaning we would see the worst case scenario across our region.  With this said we will now break down all the hazards and what we should expect from each:

Coastal Flooding:

It's appearing extremely likely we will see at least major coastal flooding from NJ up to Long Island Sound, coastal MA and coastal MA.  In fact, we may be looking at the potential for catastrophic coastal flooding/beach erosion across the areas as wave heights could potentially exceed 25-35'.  When taking into account a full moon and high tides, if the highest wave heights occur during high tide we would be looking at catastrophic coastal flooding across many coastline areas causing substantial damage and destruction to any buildings that are located right along the coast.

Damaging Winds:

Damaging winds can be expected even a far distance from the Sandy's center.  In fact, the threat for damaging winds should extend as far north as portions of VT/NH.  Depending on exact landfall, areas across NJ/SE NY/coastal CT/RI/SE MA could see sustained winds as strong as 40-50 mph with wind gusts exceeding 60-70 mph with gusts as high as 80 mph possible.  A bit further inland we could see sustained winds of 30-40 mph with gusts as high as 50-60 mph and perhaps even as high as 70 mph...this would include all of CT up through central MA.  Further north from here sustained winds of 25-35 mph is possible with gusts as high as 45-50 mph possible.  For the higher elevations of northern New England above 1000' and especially 2000' winds could gusts as high as 65-75 mph.  Not only will we be looking at the potential for such strong sustained winds and extremely strong wind gusts but the duration of these winds could last for up to 24-hours, although the higher end range of the gusts should be closer to 8-12 hours.  Winds of this magnitude for such a long duration would lead to widespread tree damage/power line damage resulting in widespread power outages and leaving some people in the dark for days.

Torrential Rains/Inland Flooding:

The heaviest rainfall totals are expected to be to our southwest and west where as much as 5-8'' of rainfall can be expected, however, across New England some areas will receive as much as 4-6'' of rainfall.  What we have to watch for are areas just to the east of the Berkshire Mountains, Worcester Hill, Green Mountains, and White Mountains as SE/E winds would lead to upsloping, making for areas of very intense rainfall rates leading to higher totals.  While the inland flooding threat doesn't appear to be too extreme we certainly will see areas of flooding, especially along rivers/streams/brooks.

Impacts from Sandy may begin as early as tomorrow evening (however, waves/surf will begin increasing as early as tonight) as winds begin to slightly pick up and bands of heavy showers move into the region.  The worst of Sandy is expected to occur between late overnight Sunday, lasting through all of Monday and into the first part of Tuesday.  This is expected to be a very dangerous storm causing numerous issues across a very large area.  Below is a graphic showing where the main hazards exist:

Hurricane Sandy to bring major impacts to much of the Northeast

As we continue to draw closer to the end of the weekend and beginning of next week confidence continues to rapidly increase that much of the East coast, from the Carolina's up through New England will be experiencing extreme issues.  While technically Sandy may be classified as a strong Tropical Storm or weak Hurricane by the time she gets up this way DO NOT and I stress DO NOT take that as this being any less extreme.  Strong blocking in the northern Atlantic will help prevent Sandy from escaping out to sea and keep her closer to the East Coast.  At the same time the Polar Jet working through the central US will rapidly amplify developing a very deep trough.  Computer models indicate Sandy will phase "combine" with this Polar Jet/Trough and once this occurs Sandy will undergo rapid intensification.

Sandy will create extreme issues up and down the East Coast with extremely damaging coastal flooding/beach erosion, very strong/damaging winds, widespread power outages, and numerous tree/power line damage.

For us here in southern New England there remain two possible scenarios;

1) Over the past few days there has been a set of computer models which have Sandy making landfall around the Delmarva or even as far south as MD.  In this scenario the worst conditions across southern New England would be across the coast where serious coastal flooding would occur along with very strong wind gusts leading to tree/power line damage across the coastal Plain.  Further inland, the effects would be much more minimal, besides heavy rain and isolated flash flooding winds would be a non-issue with the exception of a few strong gusts potentially leading to isolated power outages.

2) There is another camp of computer models which have Sandy making landfall further north, possibly as far north as NYC/western LI area or northeastern NJ.  This would be the worse case scenario for southern New England.  In this scenario we would be looking at extreme coastal flooding/beach erosion posing a threat to building close to the water.  There would be widespread damaging winds; both sustained and gusts, leading to widespread power outages and tree/power line damage.  We'd be looking at a several hour or more period of very intense winds.

Of these two scenarios which should we expect?  Unfortunately computer models seem to be converging on solution number two.  It's becoming quite apparent that a landfall further north will end up being the outcome and this would pose a significant risk to much of southern New England.  While it's still very possible a further south landfall occurs everyone should begin (if not already) preparing for a very damaging storm.  Anyone living close to the coast should evacuate as the risk for coastal flooding could pose a threat to lives.  With the potential for a prolonged period of damaging winds everyone should stock up on extra non-perishable food items, water, batteries, flashlights, and radios.  While the less extreme solution could certainly verify it's much better to be fully prepared now rather than being caught off guard.

By tomorrow evening more specifics will be given, especially with regards to how strong we can expect the winds to be.

What's up with Sandy? Potential for major impacts along the East Coast

If you haven't heard about Hurricane Sandy by now you will very, very shortly.  sandy developed in the southern Caribbean south of Cuba/Jamaica and actually rapidly intensified over the island to a very strong Category 2 Hurricane.  Below is the forecasted track of Sandy by the National Hurricane Center:

The National Hurricane Center is forecasting Sandy to remain a Hurricane to just east of the Carolina's while weakening and eventually weakening to a Tropical Storm just off the Jersey coast.  Now you may think that b/c it's expected to weaken to a Tropical Storm it won't be that bad here...that assumption would be 100% false.  In this case there will be a trough associated with the Polar Jet Stream working eastward through the United States.  Below is a graphic from one of the computer forecast models (the GFS) for 7:00 AM Sunday showing the trough:

You will also notice an area circled in red.  These two highlighted features will prove to be EXTREMELY important with what Sandy does as she travels northward.  First we will take a look into the area highlighted in red:

This area circled in red is showing another area of low pressure.  b/c of the position and location of this low pressure this is referred to as a "blocking" low.  When low pressures are situated in this location they are referred to as blocking lows b/c they virtually can inhibit storm systems from drifting out into the open Atlantic and keep them closer to the US Coast.  In the end it's all going to come down to the strength and even location of the blocking.  If the blocking is on the stronger side that will vastly increase the chances that Sandy will have to track closer to the East coast.  If this block is on the weaker side this would give Sandy the chance to actually work out more towards the Atlantic.  At this time, however, it appears that this block will remain strong enough to prevent Sandy from escaping to the east and into the open Atlantic.

As far as the trough goes, this trough is important b/c eventually the trough is expected to phase with or "combine" with Sandy, it's just a matter of where this occurs.  Computer models are starting to come together in agreeing that this phasing will occur much earlier rather than later...possibly somewhere just off the Carolina coastline.  Once Sandy phases with this trough along with the Polar Jet Sandy will under go rapid and severe intensification.  

What to take off this as of now?

It's still a bit too early to panic and worry, however, if computer models at this time tomorrow continue to hint at this potential hard it will be time to start preparing for major impacts form this system.  These impacts would include:

• Severe coastal flooding/beach erosion.  Coastal flooding could be extremely serious, and could be a major hazard to any structures located close to the waters.  
• Damaging Winds.  A rapidly deepening system along with an area of high pressure to our north and blocking low to our northeast would create a very strong pressure gradient over the region enhancing the potential for very strong/damaging winds.  Potential for widespread tree damage/power outages would be likely, especially with many trees still having leaves on them and the ground being very saturated leading to weakened tree roots.
• Torrential Rains/inland flooding.  The potential would exist for over several inches of rainfall across the entire region leading to rapidly rising streams/rivers/brooks.  Heavy rainfall rates over a prolonged period of time would eventually lead to areas of inland flooding, especially along rivers/streams/brooks.  

Again, at this point it's still a bit too early to really get into the specifics but the potential and confidence is increasing that there will be serious impacts along the East coast but it's unclear as to what areas will receive the most severe impacts.  All of these details will continued to be narrowed down and answered over the coming days.

If you're looking to prepare the best thing you can do is just stock up on some extra food (especially canned foods and such in case you lose power), bottled water, batteries, flashlights, candles, blankets, and radios.  

impacts could begin as early as Sunday evening, however, it appears it would be more overnight Sunday through early Tuesday but these details will also be ironed out as we get closer.  

End of October storm?

We are now entering the third week of October and the transition from summer to autumn is already well underway as the leaves have gone through the color changing process and trees are beginning to lose their leaves.  While the weather during this third week of the month will be quite tranquil with temperatures running above-average for the most part unsettled weather looms on the doorstep.

In the southern Caribbean, Tropical Storm Sandy has developed south of Jamaica is is expected to slowly track northward over the next several days.  

(National Hurricane Center graphic of Tropical Storm Sandy and it's expected movement through Saturday)

Medium/long range computer models all indicate that Sandy will continue slowly tracking to the north through the remainder of the week and next weekend into the western Atlantic just east of the United States.  While some computer guidance does suggest slight strengthening of Sandy over the course of this period it doesn't appear all that likely she will reach hurricane strength as atmospheric conditions don't appear to be very favorable.  Eventually she will be working into an area of enhanced wind shear and some drier air streaming off the United States and both will eventually inhibit her from going through rapid/intense strengthening.  

While Sandy is slowly making her journey northward some interesting developments will be ongoing across the United States, the central/northern Atlantic Ocean, as well as in and around the Aleutians near Alaska and how these developments unfold across the aforementioned areas will impact what happens with Sandy and where she heads once she gets into the Atlantic.  First, we will take a look at the United States and how the computer models evolve the developing upper air pattern over the United States.

As we move towards the weekend computer models show a developing trough associated with the Polar Jet Stream working into the northwestern portion of the United States sliding an Arctic cold front eastward.  There is agreement within the computer models that as this trough works through the country the trough will begin to amplify and strengthen causing it to dig further south.  In response to the digging trough across the central United States a ridge would be developing across the eastern United States extending northward into eastern Canada.  How this trough develops and how strong (or how far south it digs) will play a major role in what happens with Sandy as it moves into the western Atlantic.  We'll get more into why a bit further down.

Now onto the central/northern Atlantic and the potential developments there.  Computer models are showing the continued weakening area of high pressure located over the Azores as the area of low pressure that is situated between Greenland and Iceland.  When this occurs this leads to what is known as a "blocking pattern".  This is termed blocking b/c the weaker area of low pressure located between Greenland/Iceland leads to ridging in the northern Atlantic, this can prevent storm systems from escaping out to sea and keep them closer to the east coast.  The strength of this northern Atlantic ridging will also play a major role in what happens with Sandy.  

When looking across the northern Pacific Ocean up around the Gulf of Alaska computer models are also struggling with the handling and placement of the Aleutian Ridge.  This will have major impacts upstream as the strength/placement of the Aleutian ridge will vastly impact the strength of the troughing across the central United States which would affect the strength of the riding across the eastern United States and western Atlantic. Now to tie these three paragraphs together!

Below is an ensemble mean showing the 500mb height anomalies across North America Saturday evening.  The image is displaying a fairly deep trough across the central United States with a massive ridge along the east coast and western Atlantic:

  

Below is an ensemble mean showing the 500mb height anomalies across the entire northern Hemisphere Saturday evening...for this graphic we will just focus on the highlighted area showing the ridging in and around the Aleutian Islands near Alaska: 

Below is an ensemble mean showing the 500mb height anomalies across the entire northern Hemisphere Saturday evening...for this graphic we will pay attention to the highlighted area across the northern Atlantic near eastern Canada and south of Greenland:

In the end the strength/placement of the Aleutian ridge will play a major role in how the upper air pattern across the United States develops.  The stronger the Aleutian ridge and the more the center of the ridge is placed over the Aleutians the stronger the ridging just west of the western United States will be and the deeper the trough across the central United States will become which will result in a much stronger ridge across the east coast and western Atlantic.  The weaker the Aleutian ridge and if it becomes further displaced from being centered over the Aleutian Islands this would flatted the ridging west of the United States and prevent the trough along the central United States from deepening too far south leading to a more flat ridge along the east coast of the United States and western Atlantic which would affect the strength of the blocking in the northern Atlantic.  The strength of the northern Atlantic blocking will be highly crucial as well as the stronger the blocking the less chance there is of Sandy escaping and moving into the Atlantic and a much higher chance of Sandy staying closer to the east coast and working northward.  

Over the past few days several medium and long-range forecast models have been showing that the riding in and around the Aleutians may be strong enough allowing for deeper troughing in the central United States and stronger ridging across the eastern United States and western Atlantic creating stronger blocking allowing for Sandy to work very close to the east coast.  By early next week, some of the models have Sandy actually interacting and phasing "combining" with the trough and the associated Polar Jet.  in this scenario we would see a rapidly intensifying storm system.  

What should we make of all this...

The first thing to keep in mind here is this is all 7+ days out there and the accuracy of computer models in that range is very, very low.  In this range, often times computer models will tend to dig those troughs too deep as they get to crazy with the strength of factors like blocking and ridging (or troughing) around the Aleutians.  Computer models also LOVE to go phase happy with systems in the Atlantic and troughs along the East coast.  So until we get closer (inside of 4-days) we shouldn't take much out of these extreme solutions.

With this said the pattern does appear that it will become at least favorable for a period of unsettled weather, somewhere in the Monday-Wednesday timeframe with at the least potential for some periods of rain across the Northeast.  As we move further through the week and closer to next week details will become much more clear as to how the pattern will evolve and what potential impacts we may see.  

 

Anniversary of the October 3rd, 1979 Windsor Locks Tornado.

CT is no stranger to tornadoes, in fact since official records have been kept since 1950 CT has had 91 confirmed tornadoes (as of 2011) for an average of 1.49 per year.  Typically our tornadoes are on the weaker side and usually don't produce much damage outside of downed trees/power poles.  Very rarely do they produce much in the way of significant structural damage, except of course when a tree happens to fall on a building.  Of the 91 confirmed tornadoes only 4 of them have been rated as an F3 and 2 have been rated as an F4.  (Note: Since the implication of the Enhanced-Fujita scale (EF) in February of 2007 CT has not had a tornado rated higher than an EF2).  Most of the tornadoes that occur in CT occur during the months of June-July-August, this is when the combination of heat/humidity can lead to large amounts of instability which is a main ingredient in the development of tornadoes.  Typically when one thinks of October in CT you don't think about thunderstorms, severe weather or tornadoes, you think fall; changing leaves, cooler temperatures and a transition from summer to winter.  However, on Wednesday, October 3rd, 1979 arguably the strongest and most damaging tornado in modern history occurred across portions of Windsor, Windsor Locks, and Suffield, CT.  Not only was the timing incredibly rare for this area but to get such a damaging event from the storm system was even more impressive.

Leading up to October 3rd, 1979 a trough was developing and deepening across southern Canada and the northern Plains of the United States.  With each progressing day the trough continued to sharpen and deepen  dragging a cold front through the heart of the country.  Out ahead of this trough, however, there was another developing system.  On Monday the 1st a diffuse occluded front was draped from northern TX all the way northeastward through the Ohio Valley and just west of PA/NY into Canada.  By Tuesday this boundary had shifted eastward and an area of surface low pressure began developing across the Ohio Valley and slide eastward across the boundary into the Northeast prompting a warm front to shit northward towards southern New England.  Early Wednesday morning (as the graphic shows below) the low pressure had continued to deepen as it northeastward.  At 7:00 AM EST the warm front was located just south of Long Island.  As the morning and early afternoon hours went on and the surface low continued to deepen and move northeast the warm front would eventually end up over northern CT.  This would pump in warmer and more humid air into CT.

During the morning hours a secondary area of low pressure which had developed across North Carolina began working it's way northward and was soon riding up along where the warm front and cold front intersected.  By mid afternoon this feature had finally reached CT and the warm front was lifting through the state.  As the warm front moved through temperatures jumped well into the 70's with the dewpoints not too far behind.  The graphic below shows the 500mb level at 4 PM (an hour after the tornado touchdown); the secondary low was situated just west of CT with the warm front draped across northern CT with the cold front also just to the west of CT.  This placed the entire state in the "triple point" or where the warm front  cold front meet to create an occluded front.  Air associated with the triple point rises very quickly and vigorously and wind shear is quite strong as well.  Associated with this system was a vigorous piece of energy located at 500mb which was associated with very strong mid level wind fields.

With the warm front located across northern CT winds at the surface and just above the ground had switched over to a more southeasterly wind direction (helping to usher in warmer temps and higher dewpoints) while winds from 2000ft on up where more southwesterly with speeds increasing with height.  This yielded to large amounts of 0-1km helicity which meant there was a good deal of atmospheric spin.

According to some reports there were a few breaks of sunshine which occurred across portions of northern CT early on in the afternoon.  This short duration of sun helped to locally spike temperatures upward a bit.  With the combination of a very warm and moist low-level airmass in place along with cold temps in the mid-levels of the atmosphere this lead to some steep mid-level lapse rates which helped to boost up instability values.

During the mid to late morning hours a thunderstorm (which then developed into a supercell) which had developed just south of Long Island Sound was moving due northward and by early afternoon it had made it's way northward into CT.  As the supercell taped into the enhanced shear and pocket of higher instability it quickly strengthened.  Finally around 3:00 PM EST a very large and rain wrapped tornado touched down in the the Poquonock section of Windsor, CT.  Several buildings, including the elementary school were heavily damaged.  The tornado then continued to move through Windsor into Windsor Locks where it heavily damaged the Bradley Air Museum as well as causing major destruction to dozens aircraft and then into Suffield and then finally into the Feeding Hills section of Agawam, MA.  Between Windsor, Windsor Locks, and Suffield dozens of buildings were severely destroyed with several completely wiped off their foundation. When the tornado was all said and done 3 people were killed with hundreds more injured.  The 3 causalities made this the first killer tornado in the state of CT since the killer Wallingford tornado of 1878.  It is also believed the Windsor Locks tornado is the strongest tornado to hit the state in modern history and may only be rivaled by the 1878 Wallingford tornado.  The tornado caused more than $200 million in damage in 1979 USD (that works out to be about $640 million in today's money!).  To this day the Windsor Locks tornado which received a rating of a strong F4 still ranks as the 9th most costliest tornado in recorded history.  This was also the first tornado to be ranked this high on the Fujita scale since records had been kept beginning in 1950.

All in all you would never expect to get such a damaging tornado from this system.  Normally you'd see weak tornadoes (which there were a few in PA/NJ earlier on in the morning) but to expect such a strong tornado would be nuts.  While wind shear was certainly impressive along with helicity it is believed that just a little bit of heating just prior to the storm helping to boost up instability along with terrain enhancement (the storm was moving due south to north through the CT Valley and low-level winds usually are enhanced in valleys) helped to create an environment that was perfect enough for the developed of a violent tornado.  The supercell thunderstorm which was moving left to the mean wind flow "left mover" also helped for the storm to further utilize the strong wind shear in place yielding to even locally higher amounts of helicity.  Besides this F4 tornado there has been one other tornado ranked as an F4, that occurred on July 10th, 1989 and moved through Hamden, CT and diminishing just prior to hitting downtown New Haven.  Although this was rated as an F4 it is believed that this tornado was actually weaker than this.  To this day, the Windsor Locks tornado remains king for deadliest/strongest tornado in modern history to hit CT but going back in history it still sits below the great Wallingford tornado of 1878.