Northeast US weather
Good News and Some Words to the Wise
By Elliot Abrams, AccuWeather chief meteorologist
8/01/2006, 11:22:02 AM
Thursday, June 29, 2006 2:00PM
Here is some good news for the water-weary:
That's the GFS 180-hour rainfall total prediction. It shows no excessive rain in the areas still dealing with the massive flooding from the "no-name hybrid tropical rainstorm of 2006." For those who didn't get a chance to see some of the preceding reports, including a thought-provoking essay from subscriber Caleb Shaw, these are included below.
Wednesday, June 28, 2006 10:30 PM
Even though some more showers and thunderstorms will cross parts of the hardest hit areas from the recent flooding rains, the most persistent part of the storm has left the scene. In its wake, here's a sampling of rainfall totals:
I have gotten some very insightful emails during the last few days, and I wanted to share the questions and responses:
1Q. Elliot, why is there a general proclivity for storms to ride up the Eastern Seaboard instead of veering out to the Atlantic? Also, the general weather pattern has been for a ridge in the western U.S. and a trough in the East. Is this a general rule of weather lore or a recent anomaly?
1R.When there is a trough in the east, storms will come up the coast. If the trough position is offshore, there will be more of a west to east motion, and that’s how we get our droughts. The trough in the East is not a given. If you remember, last summer was hot because there was a ridge in the east. Elliot
2Q. In your “The End is Near” blog you comment about not seeing this much rain around Pennsylvania since Tropical Storm Agnes in 1972. I live in Harrisburg, and remember Agnes in ’72. This struck me as being a very similar event, just without an official storm name as you noted. I also remember how my mother used to tell me about the biggest flood she had ever seen (before Agnes, that is). That flood was in 1936. Agnes, of course, was in 1972. A 36-year difference. That thought was spinning around in my head one day about two weeks ago when I was walking along the Susquehanna. Thirty-six years out from 1972 is 2008. Could it be that the Susquehanna experiences floods of this magnitude roughly once every 35 to 40 years? What are your thoughts on this?
2R. I think that is about right. As I recall, there was a major flood around 1896, and the Susquehanna was affected by the same rains that caused the Johnstown Flood in 1889. In a way, it’s like a slot machine. You have all these potential winners (like a 7, for example) on the wheel, but very infrequently do you hit a jackpot where all the winners appear simultaneously (like a row of five 7s). Similarly, we have certain ingredients present on every weather map. However, it is rare to have a straight shot of moisture feeding into an unseasonably strong upper air storm like we had with Agnes and again this time...with the heaviest band of rain focused right on the Susquehanna Basin. Unfortunately, even if extreme events usually come every 30-40 years on average, there is no way to say if the next one is coming soon (next week, next month, next year, next decade...next..you get the picture) or may skip a “cycle.” And in forecasting, there are many situations that look like they may become extreme, but then it turns out some factor is missing.
3Q. What is your reaction to the Larry King interview this evening where Joe Bastardi was on plus there was a PhD from Harvard Medical School? The Harvard person said this storm, and (apparently) many other recently are all part of a global warming pattern...case closed. Joe Bastardi said "Welcome to the United States." What he meant was these kinds of things have happened before... such as from the 1930s to the 1950s.
3R. I don't know the right answer to this. The preponderance of scientists believe we are undergoing global warming and human activities are at least partly to blame. My impression of the Dr. from Harvard is similar to what I encountered when I questioned someone who thought everything that occurs is exactly predetermined. When I started to argue, the person simply said: "It was predetermined that you would say that and be skeptical." As you can imagine, there is no way to "win" such an argument. If every extreme event is alleged to be caused by global warming, it is obvious that this view can only be strengthened in time because there will be more extreme events (regardless of whether global warming is the reason, is a contributor, or has little to do with such occurrences)
In line with the history angle that Joe Bastardi offered, one of our subscribers wrote an essay concerning storm threats in New England. I asked the author if he would agree to have me "publish" his story here, and he agreed. Here it is. The author is Caleb Shaw.
NEW ENGLANDÃ¢â‚¬â„¢S AMNESIA
CHANGES IN THE WIND
History does repeat itself. Meteorological research suggests that a sixty year cycle, (involving the Pacific warming as the Atlantic cools, followed by the Pacific cooling as the Atlantic warms,) results in periods where New England is relatively free of hurricanes, followed by periods where New England is hit by an above-average number of storms. These periods vary, but are roughly thirty years long.
During any given year of a thirty-year-stormy-cycle hurricanes tend to repetitively strike one general area. Last year it was the Gulf Coast, as New England was spared. However History reminds us that in the past New England has been repetitively hit. For example, during the 1875-1905 stormy-cycle, 1893 saw nearly every hurricane scour up the east coast. The storms significantly altered our shorelines, which were fortunately far less developed back then.
During stormy-cycles East-coast hurricanes are more likely to deviate from the ordinary track which slices them out to sea, and more likely to strike sections of coast which are rarely blasted. In 1903 a hurricane actually hooked left, and New Jersey took a rare direct-hit, as New England got only a breezy drizzle.
After a thirty-year quiet, another thirty-year-stormy-cycle began with near-misses in 1933 and 1936, before 1938 flooded Providence with tides seventeen feet above normal topped with forty-foot-tall waves. Afterwards the Connecticut River rose 35 feet above flood stage. Lumberjacks from Minnesota were imported to help clear fallen trees in Peterborough, New Hampshire. Then in 1944 a storm reshaped Cape Cod. It is rarely mentioned by elders, for in 1944 they were impressionable youth fighting Hitler, without Cape Cod vacations. In 1954, towards the end of this cycle, Carol, Edna and Hazel tore at our shores and toppled our trees. In 1955 Connie and Diane drenched New England with two feet of rain in a week, put 40% of Worchester under water, widened the Blackstone River from seventy feet to a mile-and-a-half, and raised the Connecticut River to 30 feet above flood stage. Then the cycle ended, with a weakening Donna in 1960 and the bizarre, Boston-sparing loop of Esther in 1961.
During the 1965-1995 quiet-cycle an unprecedented amount of building took place in New England. At first some of the building was done with a clear memory of the past, and included flood-control-reservoirs, levees, and sea-walls. However even in 1968 I recall overhearing an older Cape-Codder protesting that a development called Ã¢â‚¬Å“Bass RiverÃ¢â‚¬Â� was madness, because, Ã¢â‚¬Å“That sand tÃ¢â‚¬â„¢werenÃ¢â‚¬â„¢t even there, before 1944.Ã¢â‚¬Â� The old alarmist woke me up, but he was dismissed by both the developer and the buyers. He was called a cantankerous, old Puritan who stood in the way of profit, progress, and parties.
Opposing such reckless development required an awareness that hurricanes would return, just as high tide will return. It simply doesnÃ¢â‚¬â„¢t make sense to build below the high tide line, unless one doesnÃ¢â‚¬â„¢t mind seeing their castles crumble. This common-sense was indeed stated in the 1950Ã¢â‚¬â„¢s and 1960Ã¢â‚¬â„¢s, however people built anyway, for people deeply desired happy holidays at the beach.
At first the new cottages were simple, un-insulated, sometimes without electricity or plumbing, and usually on unpaved roads with unpaved driveways. Such cottages would have been easy to replace after a storm. However it is in human nature to improve a piece of property. Also some improvements are demanded by insurance companies, which is ironic, as it means they have to pay out more, should hurricanes come.
As decades past hundreds of thousands of people had wonderful times, and the value of improved property soared, even though some perched on sand dunes that were temporary. People invested their lifeÃ¢â‚¬â„¢s savings in castles that could crumble.
Opposition to reckless development did appear, but its altruism often was watered down by selfishness. Often the opposition themselves built in beautiful, high-risk spots, and then sought to prevent others from building, (as building would spoil their views.) They used somewhat dubious science to justify their double standards. For example, the smoke from power-plants spoiled views, so they deemed windmills Ã¢â‚¬Å“scientificallyÃ¢â‚¬Â� wiser, because windmills Ã¢â‚¬Å“provided clean energy.Ã¢â‚¬Â� However if a proposed windmill threatened to spoil their view, then abruptly their Ã¢â‚¬Å“scienceÃ¢â‚¬Â� deemed windmills unwise, because windmills Ã¢â‚¬Å“killed migrating birds.Ã¢â‚¬Â� This sort of transparent hypocrisy made it harder to take real science, (such as the likely return of hurricanes,) seriously.
Sometimes this opposition focused on hurricanes, to prove reckless developments were wrong, but again used dubious science. Rather than pointing to the clear evidence of the past to discourage development, they suggested hurricanes indicated a climate change, caused by ungoverned growth. They wanted to grasp the power to govern growth in their own hands, however the implied suggestion, (namely, that they could stop hurricanes,) seems astounding. The social reforms they then proposed, (as a sort of hurricane-prevention,) had an uncanny resemblance to the social changes they would have proposed even if there wasnÃ¢â‚¬â„¢t any climate change. For example, the explanation some gave in the 1950Ã¢â‚¬â„¢s as a cause for the upsurge of hurricanes was Ã¢â‚¬Å“above-ground-nuclear-testing,Ã¢â‚¬Â� (ignoring the huge pre-atomic-age hurricanes of 1938 and 1944.) This explanation just happened to further their Ã¢â‚¬Å“ban-the-bombÃ¢â‚¬Â� political agenda.
Such people might be likely to blame the next upsurge of hurricanes on Ã¢â‚¬Å“global warming,Ã¢â‚¬Â� and the solutions they proposed might again just happen to further certain political agendas. However politics should not intrude into scientific objectivity. A psychologist would likely dismiss such intrusions as Ã¢â‚¬Å“subconscious projection.Ã¢â‚¬Â�
The scientific truth is that hurricanes have no observable physical brain; it is therefore assumed hurricanes donÃ¢â‚¬â„¢t think, and consequently donÃ¢â‚¬â„¢t care if you promote or oppose building. Hurricanes simply do what they have always done, as history repeats itself.
One reason it is difficult to impress people with historic hurricanes is because the evidence of destruction has been tidied up. Stretches of sand on Cape Cod have been turfed and treed by excellent landscapers to an amazing degree. Fertilizer is wonderful stuff. One would never dream the land didnÃ¢â‚¬â„¢t even exist before 1944 or 1893.
As a boy I was walked through a forest of young trees strewn with big, parallel logs. The logs were entire stands of trees which had fallen in 1938 or 1954, but those logs have now rotted down to flat stripes of green moss on the needled forest floor, among tall trees over a half century old. ItÃ¢â‚¬â„¢s difficult to believe, amidst such shady, sheltered majesty, that a forest can be flattened in an hour. However the Ã¢â‚¬Å“Great September GaleÃ¢â‚¬Â� of 1815, (described in a poem by Olivier Wendell Holmes Sr.,) did exactly that, over large parts of New England.
Another problem with a sixty-year-cycle is that one can be fifty-years-old and say, with all honesty and sincerity, Ã¢â‚¬Å“The weather isnÃ¢â‚¬â„¢t like it used to be.Ã¢â‚¬Â� One has to live twenty years longer to look back and say, Ã¢â‚¬Å“The weather is as I remember it being in my childhood.Ã¢â‚¬Â� It is a case where it is wise to respect elders, and unwise to trust our personal experience. An old alarmist can sound like Chicken Little for fifty years, before abruptly becoming a Paul Revere.
The current thirty-year-stormy-cycle began around 1995. The Pacific is cooling right on schedule, and the Atlantic is warming. We are now able to watch it happen with satellites which did not exist the last time the Atlantic warmed, and in some senses we are seeing things for the first time. For a meteorologist, this is as exiting as exploring a new frontier.
Some of the things that are occurring are raising eyebrows. Unexpectedly large areas of atmospheric-uplift are occurring over the Atlantic, and some meteorologists suggest this uplift may result in larger-than-usual hurricanes. Records of such unusually large hurricanes exist in our pre-space-age records, but, because they occurred before satellites could photograph and measure them, and even before the Weather Bureau existed to record them, there have been doubts whether the old records are scientifically valid. Skeptics have scoffed at old reports of larger-than-usual hurricanes as being mere exaggerations, and have dismissed them as being the result of old Yankees sitting by a fire and spinning yarns. Now it is starting to seem such tales might not have been as tall as they first appeared.
Therefore it might be wise to consult the old data, and see if the structures we have built can withstand what happened in the past. After all, it has been a half century since Carol deforested our hills and Dianne dropped twenty inches of rain. Are our levees and sea-walls in good repair? Will our aging flood-control reservoirs be able to withstand a true test of their design?
In order to become properly alarmed it helps if one takes the attitude of an insurance company. Their agents are always seeing potential dangers, raising our rates if we have a little danger like a barking dog. A major hurricane, however, is not a little danger. The forces involved are difficult to comprehend, and in some cases defy common sense.
For example, common sense might conclude a wind of 110 mph is 10% stronger than a wind of 100 mph, however in fact it is roughly twice as strong, (100%,) and a 120 mph wind is roughly twice as strong as a 110 mph wind. Few in New England have any idea of the damage a storm such as the 1938 storm is capable of. In many ways New England is no more prepared for a repeat of the 1938 hurricane than New Orleans was for Katrina.
Next time you drive down our shady streets, look up at the electrical wires, and imagine 10% of our beautiful trees blown onto those wires. (On some hills, imagine 100%.) Also understand there are far more trees in New England now than in 1938, (and far fewer roadside elms, which withstood wind better.) We tend to gripe when the electricity is off for six hours. Can you handle six days? How about sixteen? Or even six weeks?
Our builders have displayed amnesia for fifty years, and have built on riversides that were under twenty feet of water, and on dunes that were below raging storm tides, and atop hills that were scoured by winds over a hundred miles an hour. Add some shade trees crashing onto roofs, and we are likely to have some homeless neighbors, if we are not homeless ourselves.
We have also become far more dependant on computers and cell phones. Look carefully at the flat receivers up in cell-phone towers, and imagine them stressed as winds rise past a hundred. (In 1954 the WBZ radio tower was blown over by Carol, resulting in new building codes for such towers.) Will we be able to telephone anyone, after a storm?
Cell phone companies go through great efforts to keep their receivers firmly anchored atop sturdy towers. Receivers must be able to withstand stresses such as thick, heavy, winter ice, for the receivers must be very carefully aimed to transmit correctly. The companies are aware of the power of wind, and competition forces them to try to be better than each other at repairing receivers bent ever-so-slightly out-of-line by hurricane-force winds. After storms their crews race each other to be back-on-line first, transporting mobile generators, and even mobile receivers, however repairs can be slowed if fallen trees and flooding make roads impassable. After a major hurricane one should therefore expect to have no phones for a while, besides having no electricity.
This sort of alarmist talk worries some, if only because they figure insurance companies may raise rates, if they hear about risks. However insurance companies should perhaps worry less about our barking dogs, and instead focus more on the integrity of their own high-rises. Both the Prudential Building and John Hancock Tower in Boston were built after the last major hurricane and before building codes became as strict as they now are. Both structures had design flaws that were exposed during construction, and old-timers can remember the windows popping out of the John Hancock Tower at such an alarming rate that the sky-scraper was more or less sheathed in plywood. Lastly, due to the experience of Ã¢â‚¬Å“The Big Dig,Ã¢â‚¬Â� Bostonians are not entirely confident builders obey codes, even when codes exist. Alarmists can therefore gloat about the situation insurance companies now find themselves in; after all, a falling skyscraper does a lot more damage than a barking dog.
Anyone who has been up in high-rises during a gale knows they do sway in a most alarming manner. One then hopes the engineers knew what they were doing, and also wonders what fatigue occurs to the metal and concrete which form a high-riseÃ¢â‚¬â„¢s trunk and roots, especially as decades of winter gales blast it, and the swaying building ages. (The 1978 blizzardÃ¢â‚¬â„¢s peak winds gusted to 125 mph.) Lastly, one knows the codes have become more strict, and one then wonders if this means the older buildings are suspect; after all, codes are made more stringent for definite reasons.
In actual fact no engineer wants his name attached to a building which comes crashing down, and the engineering that goes into such massive structures is amazing and, to some degree, reassuring. A building like the John Hancock Tower sticks up like a huge, flat sail, and therefore must have a huge keel, and it turns out high-rises are imbedded into astounding amounts of reinforced concrete. Such buildings are designed to withstand winds 25% higher than the worst ever recorded, in the area they are built.
However, if you are a true alarmist, you hesitate at those words: Ã¢â‚¬Å“The worst ever recorded.Ã¢â‚¬Â� The worst winds recorded in Boston are recorded at Logan Airport, down at sea level. The tops of high-rises thrust up into winds which are far higher. Considering the force exerted by wind increases roughly 100% with every ten mph, construction costs also increase greatly if one builds a structure to withstand a wind only ten mph higher. Besides the pressure of wind, engineers also face the pressure of budgets, and therefore must decide Ã¢â‚¬Å“what they can get away with.Ã¢â‚¬Â� Their decisions have been excellent so far, for wind has never toppled a high-rise, however a true alarmist notes no high-rise has yet been truly tested, especially in the north, where codes are not as demanding. No high-rise has yet faced a direct hit from a F-5 tornado, and BostonÃ¢â‚¬â„¢s have never been tested by a major hurricane.
Recalling the words, Ã¢â‚¬Å“the worst ever recorded,Ã¢â‚¬Â� one hurries back to the data, and discovers there is no data involving a worst-case-scenario. A worst-case-scenario would take a major hurricane through BostonÃ¢â‚¬â„¢s western suburbs; when Donna took that route in 1960 it had been downgraded to tropical-storm status. The next closest pass was the Great Atlantic Hurricane of 1944, however it passed to the east, with its most devastating east-side winds away from Boston, over Cape Cod. The worst hurricanes of the last 30-year-stormy-cycle, the 1938 storm and Carol in 1954, both passed west of Worchester; however the 1938 storm, even with its center over the Connecticut River, was still able to sustain winds of 73 miles per hour, with gusts to 87, at BostonÃ¢â‚¬â„¢s Logan Airport. One wonders what itÃ¢â‚¬â„¢s winds were like at the altitude of BostonÃ¢â‚¬â„¢s high-rises, and a true alarmist glances south to the summit of the Blue Hills, just south of Boston. At an altitude of 681 feet, on September 21, 1938, the Blue Hills anemometer registered steady winds of 121 mph, with gusts to 186.
If one transposes the tracks of Carol or the 1938 hurricane east, so they pass through the western suburbs of Boston, the cityÃ¢â‚¬â„¢s high-rises would be exposed to tremendous stresses. When I asked an engineer whether such buildings were designed to withstand winds of 186 miles per hour, his reply was, flatly, Ã¢â‚¬Å“No.Ã¢â‚¬Â� He did add that it was likely a high-riseÃ¢â‚¬â„¢s windows would give out before the steel beams, and stress would be greatly reduced once the wind could pass through the structure, rather than around it. I found this reassuring. It is much better to have glass, copiers, office desks, computers and filing cabinets raining down onto the streets of Boston, than to have it be entire buildings.
In other words, after a major hurricane you might not be able to get in touch with your insurance company right away. This is no reason to panic. It might not happen. The odds of it happening are less than the odds were of Katrina hitting New Orleans. Anyway, even if people do panic, I doubt insurance companies will hurry to take down their towers.
An old saying states, Ã¢â‚¬Å“Hope for the best, but plan for the worst.Ã¢â‚¬Â� A calm and wise response, as hurricane season approaches, is to consider storing some extra food and water, and purchasing a camping stove and generator, rather than buying the latest four-wheeler or jet-ski. Be pragmatic. At times pragmatism is the only insurance that canÃ¢â‚¬â„¢t be cancelled. It faces the fact mails may be delayed, and rescue helicopters may be busy elsewhere, so it simply plans to be self-reliant for a while. After all, hurricanes have happened before, and left us with data we can study and expect to see repeated.
To instead prefer amnesia about our past is a willful act of foolishness. It is to deny data and go cruising for a bruising. It is to prefer to be ignorant, and such ignorance is currently all too common in New England, even as proof history does repeat itself promises us another 1938 hurricane, another 1944 Great Atlantic Hurricane, another 1954 Carol, Edna, and Hazel, another 1955 Connie and Diane, another 1960 Donna and even another 1961 looping Esther. It is only logical to assume we will face a period of time when we will be tested.
It is useless to blame anyone for the testing we face. The same rain falls on Republicans and Democrats alike. It helps no one to sit about whining about the unfairness of having to reap what grandparents sowed; rather, when the tide comes up, itÃ¢â‚¬â„¢s time to shift the towels.
The tide we now face is a tide which takes thirty years to withdraw and thirty years to return, and, while it is a matter of debate whether prayer and fasting can shift the tracks of individual storms, prayer is not usually used to stop tides, nor to stop time. Such changes are a given, whether you are a Conservative Christian or Secularist or Islamic Terrorist. They are simply in the wind.
If you have any thoughts for me or for Caleb, send me an email. I am on vacation through next week so I cannot respond to all my emails. However, I read and appreciate every one.
Wednesday, June 28, 2006 7:45 AM Yes, the end of the siege of steady heavy rain, with historic flooding, is now in sight for the Middle Atlantic region. Things are proceeding pretty much as outlined here early yesterday (Tuesday): the storm from the Florida-Georgia coastal area would roll up the coast, first enhancing rain ahead of it, then pulling in drier air behind it. Unfortunately, the main stems of a number of rivers, such as the Susquehanna, often do not crest until well after the worst rains are over. In this case, many crests from this major flooding event will not come until tomorrow (or even later downstream). This storm is being compared with Agnes, the Tropical Rainstorm that battered the Susquehanna and other basins in June of 1972. Kristina Baker's story, as well as one by Bob Tarr in the accuweather.com news section, go into this in further depth. This enhanced IR satellite picture showed the setup over the Northeast early this morning:
Now even though the largest batch of rain is leaving Pennsylvania today, there will still be more rain. It appears that convection associated with the cool trough now inching through the East will initiate new showers and thunderstorms from the middle of Pennsylvania into Maryland late this afternoon or tonight, and that rain will then head into New England. The previously hard-hit areas of New England have been generally spared the worst from the current storm but are not out of the woods. Rain from the existing batch of precipitation (the part exiting Pennsylvania) still has to cross New England, and the new rain from Pennsylvania will move across New England tomorrow. Pro site subscribers can see the NAM series of surface map/precipitation forecasts here:
NAM0628066Z The time period leading up to 8 a.m. tomorrow (Thursday) shows a substantial area of heavy rain focused on southern and central New England:
However, my impression is that while this batch of rain will cause local flooding in poor drainage areas, we are not looking at a long-term siege of heavy rain that stays over the same places for hour after hour after agonizing hour. Remember to check the latest information on accuweather.com for up to date information that cannot be contained in this once-in-a-while vacation period posting (I am on vacation until next Friday.) Before signing off, I wanted to show you two maps showing radar-estimated rainfall. The first is from the radar at State College, Pa., and shows how much of the main stem of the Susquehanna River basin has received 4-12 inches of rain. I don't recall this much rain in that area during late June any time since Tropical Storm Agnes devastated the area around this time in 1972. The current storm, which never got a name, has caused widespread disruption, partly because of its access to tropical moisture. This, plus the storminess that battered the Houston area last week, shows one weakness of naming storms solely on the basis of wind.
Finally, here is the same kind of map, except from the "Philadelphia" radar located near Mount Holly NJ:
You probably notice that the Philadelphia total rain radar does not show as much rain as the State College radar. The reason is that the State College radar includes all amounts since the 23rd (last Friday) whereas the Philadelphia radar only includes what has fallen since the 26th (2 days ago). A number of us have commented on the strengths and shortcomings of some of the models we deal with every day, but this is the second time in two months when the GFS 180-hour rainfall prediction signaled major flooding. The first time was during the week before the eastern New England flood in May, and the second time was last week's prediction for this event. On our free site (accuweather.com) you can find an archive of each blogger's articles. Here's what I said about this situation last Thursday (June 22): I'll have more to say later, but the GFS 180-hour rainfall forecast is nothing short of stunning. We have to remember, however, that it is just one of several progs, and many weather events are conditional: a certain set of events needs to occur in order to set the stage for what comes next. If any of the linkages break down, other scenarios become more likely. But, in the worst case, this model may be on to something... and that something is the possibility of historic flooding in some parts of the East within the next week. Here's the map:
Now, since I have only shown you a few extreme predictions (this one had a large area getting 10+ inches of rain), you may think this model does the same thing all the time. It doesn't. Here's the 180 hour estimate from last night's 6Z run. It does show a fair amount of rain, much of it probably from the last phases of the storm that has besieged the East this week.
Tuesday June 27, 2006 1AM The extremely wet weather pattern for the East has certainly materialized, with the Washington, D.C., area getting inundated Sunday and east-central and central Pennsylvania getting drenched on this Monday night. Looking at the patterns of heaviest rainfall, we see a steady northward progression since Saturday, and there is little reason for this to change. South of where the heaviest steady rain is falling, it is far from dry. In fact, most of the radars lining the area from Virginia to Georgia show patches, pockets and bands of rain and thunderstorms that can easily flood streets and raise streams over small areas. Looking at the broad-scale flow pattern, it appears the key to ending the deluge is the northward movement of a relatively weak (wind-wise) but very potent (rain-wise) low pressure area off the Florida and southern Georgia coasts. I would call this the caboose of the series of waves or pulses of energy that have been embedded in the deep southerly flow that is washing over the East now. But what is a caboose, other than a relic found in model train sets? Cabooses are no longer generally used by railroads. So maybe we can call the low pressure area the last car on the train. Whatever we call it, it appears that the feature will suppress rainfall well ahead of it, enhance rainfall as it approaches new places on its trek north, but then pull in drier air from the west as it departs. What this all suggests is that the lull in the steadiest rain from eastern Virginia to extreme eastern Pennsylvania and New Jersey into central and eastern New England will last through today (Tuesday), but then these areas will get successively immersed in the final area of rain as it rolls up the coast. It remains to be seen how much this last load of rain will affect already swollen and flooded streams and rivers, so it is very important for you to heed local warnings and directions from Emergency Management Agencies in your home locations. I would add that if you are not getting the information you need, you should let your local elected officials know. The following set of eastern radars from late Monday night illustrate the patterns I have talked about so far. First, we'll look at the extended-range pictures from the State College, PA, Sterling, VA, and Charleston, SC, radar sites. You can see that the largest areas of steady rain are in the north now, but that heavy showers and thunderstorms are common well southward.
So is there any way out of this setup? It appears there will be a change later in the week. The ECMWF shows it well in its series of 500mb progs for this Thursday through Saturday. Watch the way the major trough is still well inland Thursday, then moves bodily eastward and out of the way by Saturday. This will bring dramatic drying to the the waterlogged East.
In short, there is more rain, and more flooding, to go with this siege, but at least we see the light at the end of the tunnel. Again, I want to stress the need for you to get the most detailed local information you can through your local outlets or from EMAs in your area. They will have the latest exact river crest forecasts and action plans and advisories for you.
The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com
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