Ridging will bring warmer temperatures and drier weather. This causes regions to be drier, wetter, cooler or warmer than normal.
Air pressure comparisons between distant regions is often used to assess the long range weather pattern. Latitude, elevation, distance from moisture source(s), ocean currents, and topography all contribute to the expected weather.
A climate control(s) can be so dominating that the same weather will repeat for weeks on end. Students guessed what months they thought were the hottest and the coldest and started completing the table I created for this lesson, Weather Temperature Data Over Years.
Then once they had the data for two previous years, they made predictions and documented all of their findings on AVERAGE TEMPERATURE IN NJ TABLE. Because the students had to find the hottest and coldest months, I felt that they took a closer look at the table than if it was just a fill in the blank and go situation, this is not your typical worksheet.
The discussion at the end was essential if I wanted my students to make even more meaningful connections to the content, for this reason, I created Evaluate our weather findings and predictions. Not only did it make them think of what the different temperatures represented, but I brought it back to the original question of helping a tourist decide when it would be best to visit New Jersey based on the activity they wanted to do.
For example, the weather could be cold and rainy for several days in a row. Another example is a month of repeating hot and dry weather.
Troughs and ridges can become locked in position for many days or weeks in a row. The region in transition from the trough to the ridge with winds from the south tends to have the best rain changes especially if the southerly flow is also bringing up moisture.
The region in the transition from the ridge to the trough with the northerly winds tends to have drier weather since the cooler air does not have as much moisture. Also, if the northerly winds are from the continent they tend to have lower dew points.
The previous posting was on the 25th of November (you can read that one here) and I waited to update with a purpose. In that previous post, I ended with: “Looking ahead I suspect that mid-December ought to get fascinating based on a hunch, thinking the wavelength is around 55 days give or take.
“I now believe the wavelength (cycle) is on a shorter timescale; perhaps as short as 48 days, but that would have still led to an active mid-December for at least southwest Kansas and into western Oklahoma. The geographical region targeted by these storms has been relatively small in areal extent.
Not all locations of the drought area has benefited which continues to be a concern. For December, there has been what would now be considered a near record amount of snow at some locations.
The 3 storms have targeted basically the same area but with a tight gradient (especially to the north) of very little to a bunch! The drought map shows improvement where it snowed significantly.
After this last storm on the 15th, the snow field was pretty impressive viewing from satellite.... And here is the snowfall map from the storm on the 12th/13th and notice the target area is basically the same....
One key element through the end of December will be the Arctic Oscillation. It has gone strongly negative (very cold air building up in the high northern hemispheric latitude region).
Essentially this cold air buildup which is reflected in the negative index will help to energize the polar jet stream even more than it has been. The next two systems impacting the central U.S. will be fast moving with little or no moisture to work with, so I don't believe we'll see much precipitation, if any, and only a glancing blow of cold air.
So with a pretty good idea of the cycle length, if I'm right about the time period, then here is what I expect... Those areas of the high plains without snow cover will see a few days next week that should be pretty mild!.
Timing of particular fronts will always be a challenge across the high plains, regardless of weather patterns in place. However, if that storm does occur, it is impossible to predict if it will be the southern, central, or northern high plains.
Based on what has been going on this month and with the projected phase of the Arctic Oscillation, I would favor the odds to be closer to southwest Kansas. This current weather pattern cycle began around Oct 7.
Of the top 20 wettest periods (10/7 through 12/16), here is what occurred the following spring and summer... Later this winter I'll jump forward with an outlook for the spring and summer.
I would like to see another cycle of this weather pattern and nail down the actual periodicity. Meteorologists have over time found it quite common to find specific weather conditions within a given location to be locked within a repeating pattern on a daily basis.
Surface areas forecasted which have the tendency to be located within a trough will tend to exhibit cooler climates than normal. This observation has allowed the conclusion to be formed that areas located within ridges and troughs can experience weather conditions in locked patterns occurring from a few days to several weeks at a time.
Similarly, regions mostly affected by winds approaching from a northerly direction will tend to have a much cooler than normal weather condition. Specific regions within designated areas between the trough to the ridge and impacted by winds approaching from a southerly direction are most likely to be affected by instances of rainfall.
The possibility of rain within such areas is also increased in the event that a high concentration of moisture is brought by those southerly winds. Today, we have powerful supercomputers that simulate the atmosphere using sophisticated mathematical formulas, and they are increasingly enabling us to forecast the weather accurately many days in advance.
A forecast of upper-atmospheric weather patterns valid Nov. 14, 2013, made by the American GFS model nine days earlier on Nov. 5, 2013. By Nov. 5, all major computer models agreed that an unusually strong zone of high pressure would be near Alaska nine days later.
Earlier this month, on Nov. 5, I noticed all the major computer models were forecasting a massive ridge of high pressure in the upper atmosphere over the Aleutian Islands of Alaska on about Nov. 14 (see inset map). It so happens that the Climate Prediction Center (CPC), an arm of NOAA, publishes analog dates for upper-atmospheric patterns expected one to two weeks in advance.
These analog dates correspond to times when similar atmospheric patterns were observed in the past. As it turns out, three days after that unusually strong high-pressure pattern showed up over Alaska this year, a major tornado outbreak raked states as far north as northern Michigan on Nov. 17.
After all, some CPC analog dates showed tornadoes on the Gulf Coast and one or two had little or no severe weather at all. Except for a strong low pressure system near Canada's Hudson Bay on the 2013 map and a weak frontal system in the southern U.S. on the 1963 map, most of the high and low pressure centers and fronts are very similar in strength and position.
That coincidence piqued my curiosity even further, so I looked up NOAA's daily weather map for that date. Given some talk of a Thanksgiving storm along the East Coast, I thought I'd take a look ahead and find out what came of the 1963 pattern.
That low then intensified significantly as it moved into Georgia on Nov. 29, 1963, and became a powerful 975-millibar storm centered over New Jersey by early Nov. 30. It was accompanied by strong winds and rain across much of the Northeast; the snow was confined to places well inland such as Syracuse and Pittsburgh, and it wasn't particularly heavy.
Boston surged into the 60s for a few hours overnight Nov. 29-30 as the storm pulled warm air north on a southerly wind. Well, computer models are in broad agreement on forecasting some sort of significant low pressure to come up the East Coast during Thanksgiving week, albeit a little earlier than the 1963 storm did.
(Credit: Maria Lemming)When we talk about climate change today, we have to look at what the climate was previously like in order to recognize the natural variations and to be able to distinguish them from the human-induced changes. Researchers from the Niels Bohr Institute have analyzed the natural climate variations over the last 12,000 years, during which we have had a warm interglacial period, and they have looked back 5 million years to see the major features of the Earth’s climate.
The Earth’s climate system is characterized by complex interactions between the atmosphere, oceans, ice sheets, landmasses and the biosphere (parts of the world with plant and animal life). Astronomical factors also play a role in relation to the great changes like the shift between ice ages, which typically lasts about 100,000 years and interglacial periods, which typically last about 10-12,000 years.
The researchers studied: Temperature measurements over the last 150 years. But if we can determine the relationship between the variations in a given period, then we can make an estimate.
These kinds of estimates are of great importance for safety assessments for structures and buildings that need to hold up well for a very long time, or for structures where severe weather could pose a security risk, such as drilling platforms or nuclear power plants. We have now studied this by analyzing both direct and indirect measurements back in time,” explains Peter Ditlevsen.
There has been speculation that the reason could be astronomical variations, but we can now rule this out as the large fluctuation during the ice age behave in the same ‘fractal’ way as the other natural fluctuations across the globe,” Peter Ditlevsen. The abrupt climate changes during the ice age could be triggered by several mechanisms that have affected the powerful ocean current, the Gulf Stream, which transports warm water from the equator north to the Atlantic, where it is cooled and sinks down into the cold ocean water under the ice to the bottom and is pushed back to the south.
This water pump can be put out of action or weakened by changes in the freshwater pressure, the ice sheet breaking up or shifting sea ice and this results in the increasing climatic variability. We have to go very far back into the geological history of the Earth to find a climate that is as warm as what we are heading towards.