Don Paul

A Muggy Period, and then Back to Seasonably Cool

August 6th, 2013 at 11:36 am by under 4 Warn Weather

As temperatures and dewpoints begin climbing for a few days, we’ll be reminded it’s still summer. However, we’re not going back to the oppressive heat and humidity of mid July…just routine mugginess. Scattered showers & tstorms will become more likely on Wednesday and Wednesday night (and we’ll have to monitor those tstorms for intensity, although the Severe threat appears rather low). After a weak cold front goes by, any showers will be winding down early on Thursday on the Niagara Frontier, but they may linger longer closer to PA. In any case, this weak cold frontal passage will not usher in noticeably drier air. It will remain on the muggy side into Friday evening. A wave of low pressure riding that front will send more showers & tshowers into at least the southern half of our viewing area into Friday evening, with maybe some activity reaching up to the Niagara Frontier…the farther north, the lower the chances of showers. During Saturday, cooler & drier air will return with skies becoming partly to mostly sunny.

Overall, the northern branch of the jetstream will again dip over the Great Lakes, while the warm ridge of high pressure will remain planted over the interior of the western US. This pattern will prevent any return of truly oppressive heat & humidity over the next 16 days or so. At times, temperatures will run below average, and at other times closer to average. But true “heat wave” conditions are out of the picture well into the month.


Summer…”REAL” Summer…has Taken a Summer Holiday

July 29th, 2013 at 10:34 pm by under 4 Warn Weather

A persistent pattern of a ridge over the interior of the west (Warm) and a trough over the Great Lakes and the east (Cool) has developed, and appears likely to stay in place for at least a few weeks to come. There will be minor variations within the persistent pattern. However, without a strong eastern or midwestern ridge, or a Bermuda high to pump up warm, humid air, an extended period of hot & humid weather will be near impossible in the Great Lakes into mid-August. In fact, the scope of this pattern will keep temperatures running average to below average from north of Wichita to central Canada, across the midwest, Ohio Valley, Great Lakes, mid-south, and much of the NE and middle Atlantic states. The coolest part of this vast region will tend to be over the Great Lakes and the interior of the NE. This does not mean a ridge won’t rebuild after the 13th or 14th of August. It just means we won’t see such a ridge until that time at the earliest. This is a high confidence outlook, in that there is good agreement in all the ensemble means.

Of course, this is a vastly different pattern than that of 2 weeks ago, when we endured a week of heat and high humidity. At that time, there was an unusually strong and hot ridge of high pressure near us, blocking any advance of Canadian airmasses. Now we’re in a pattern during which one cold front after another will be crossing the region every few days. It may get cool enough again by Friday night for some lake effect showers to reappear, with chilly air aloft over the warm lakes. Speaking of the lakes, Lake Erie had reached 78 degrees 2 weeks ago, 6 degrees above average for that date. It has since slipped to 73, which is normal for July 29th, and is the normal highest temperature reached during the summer months over a period going back to 1927.


No Temperature Extremes for A While

July 22nd, 2013 at 9:52 pm by under 4 Warn Weather

After the drip, drip, drip of perspiration last week (which became a legitimate public health threat for elderly, asthmatics, and infants in non-airconditioned housing), the minor league mugginess at the start of this week will be very easy to take. Even that mugginess will not stick around long. Another fairly strong cold front will cross the region Tuesday night, followed by much cooler and less humid conditions on Wednesday, and only modest warming by the weekend. Another cold front will likely cross our region by Sunday, with cooler than average temps returning as early as Sunday into early next week.

In the overall scheme of patterns, all the major ensemble means (500mb) show no rebuilding of a strong ridge near the Great Lakes or the NE. This will allow occasional brief warmups, but only to “seasonable” warmth, a little above average. These will be followed by cooler periods, but not so cool (or wet) as to cause many disruptions in outdoor activities. We’ll probably see some scattered showers & tshowers or tstorms on Saturday in advance of that next cold front, in addition to those which occur on Tuesday (this week) in advance of the closer cold front.

None of this is to suggest “we’ve peaked”, since there have been hot spells (some of our hottest) in late summer quite a number of times. The recent extraordinary, brutal 600 DM ridge built itself up, after all, following a period of troughiness/coolness in the Great Lakes, NE & Ohio Valley. It IS to suggest, though, that my confidence is high we’ll see no “heat waves” in the next 16 days (date of this post is July 22).


After a Cold Front, some Temporary Relief from the Humidity…and some Dry Weather

July 9th, 2013 at 2:06 pm by under 4 Warn Weather

A few spotty showers during this humid afternoon may become a bit more numerous later today, especially if some sunny breaks develop–at which point some rumbles of thunder may develop. Humidity has actually crept up a bit higher today, making for some discomfort even with ordinary temperatures in the 70s. A few shwrs/tshwrs with sparse coverage may still be around occasionally overnight, with continued uncomfortable humidity. The metro area morning low will be around 72.

On Wednesday, the approach of the 1st of 2 cold fronts will help trigger a couple of rounds of SCT Shwrs & TStorms. SPC continues to have our viewing area at Slight Risk for Severe Tstorms, where the primary threat (if any become severe) would be damaging straight line winds. If we keep overcast skies, the reduced heating would make the Severe risk strictly marginal. With some sunshine, the threat would increase somewhat, especially to the S & E of a developing brisk Lake Erie breeze. That breeze may “shadow” the metro area and a large part of the Niagara Frontier with less chance for tstorms due to the cooling stability from the Lake. The Shwrs & Tstorms will gradually diminish from NW to SE Wednesday evening. Thursday will be somewhat less humid, but a secondary cold front may trigger a few minor showers in the afternoon. Behind that front will be still less humid air, which will stay with us into Saturday. During the weekend, temperatures will begin warming. Saturday will be the more comfortable day to stroll The Taste, with moderate (not high) humidity beginning to build on Sunday, along with a high of 84 or 85. The mugginess will be more noticeable by Monday. However, excepting those few possible lighter showers Thursday afternoon, we should be rainfree into next Tuesday once we get by these cold fronts and their temporary relief from the humidity.

As a warm ridge of high pressure rebuilds during the weekend, temperatures will run above average beginning Sunday for most days through next week. There are no signs of  a “heat wave” or anything extreme, but the temporary cooling troughiness over the Great Lakes will not be sticking around for long as 500 mb heights go back above average over much of the country, including our part of it. Initially, this next stretch of mugginess next week looks more stable and less likely to deliver large convective outbreaks into WNY. However, there is some suggestion the flow aloft may again veer from SW to WNW later next week, which would allow short waves to return some rounds of showers & tshowers to the Great Lakes. As you’d guess, there is the usual uncertainty with guesstimating precipitation  8-10 days out. But at least I’m not seeing signs of a return to that trough-to-the-west and Bermuda High to the east, pumping up huge amounts of Gulf water vapor.


Climate Change; “Nonlinear” but ultimately Global Warming Will Continue to Grow

June 28th, 2013 at 10:48 am by under 4 Warn Weather

At my recent American Meteorological Society conference in Nashville, I was privileged to attend a day long short course on climate change (I’ve completed several such courses), led by several of the nation’s most accomplished climate scientists. This intense and amazingly inclusive day included basic and more advanced materials on what we know–and what we don’t know–about climate change and global warming. (The scholars lecturing included Deke Arndt, Chief of the Climate Monitoring Branch of NOAA’s National Climatic Data Center; Dr. Tony Broccolli, atmospheric scientist and Director of the Rutgers Climate and Environmental Change Initiative, and Chief Editor of the Journal of Climate; Harold Brooks, reseach meteorologist and Senior Scientist in the Forecast Research and Development Division at NSSL, the National Severe Storms Laboratory; Dr. Keith Dixon, research meteorologist and climate modeler at the NOAA Geophysical Fluid Dynamics Laboratory/GFDL in Princeton; Dr. Ben Santer, physicist and atmospheric scientist at the Lawrence Livermore National Laboratory, University of California; and Marshall Shepherd, AMS President and Department Chair of the University of Georgia’s Atmospheric Sciences Program.)

A few basics: CO2 is indisputably a greenhouse gas, which traps heat which would otherwise radiate back into space. Without water vapor and CO2, the earth would be a frozen ball. The basic physics are known, and not in dispute. CO2 has been increasing since the dawn of the industrial revolution. The burning of fossil fuels produces CO2. The increase has now taken us to 400 parts per million in the atmosphere, the highest level in at least 800,000 years and probably more than 1 million years.

http://www2.ucar.edu/atmosnews/opinion/9574/five-things-know-about-carbon-dioxide

Other greenhouse gases such as methane, also increasing, are much stronger as greenhouse gases. But the sheer volume of CO2 has far outstripped the capacity of methane in warming capacity. In addition, CO2 has a long, stable shelf life in the atmosphere once it’s released. Methane, which may increase more rapidly due to the melting of the Arctic permafrost and the possible release from slowly warming seabeds, has a life of just 14 years in the atmosphere.

The worst news is that a large portion of the past and future warming will be largely irreversible for at least a couple of centuries, due to that CO2 shelf life, and projected increases in CO2 from economic growth in nations such as China and India. (The US CO2 output has decreased significantly in recent years, due to the recession and even more so due to the lower cost of natural gas vs. coal and oil. Natural gas emits only 40% of the CO2 produced from burning coal.) But there is still good evidence that the size and effects of the warming can be mitigated to some extent by some element of reduction in the burning of fossil fuels. The mitigation involves social and political issues which I will not get into, since I have no more expertise on those topics than any of you…I’ll try to stick to the science.

The warming is “nonlinear” in that it will occur at an uneven pace. There can be embedded within the long term warming cooler periods, and some periods in which warming accelerates. Such a chart looks “spikey” with ups and downs, while the median continues to inexorably climb. We have, in fact, seen a slowing of the warming between 2000-2010. The best theoretical evidence on what caused that slowdown involves the oceans acting as a carbon and heat sink. That is, the ocean has been taking up a good deal of the extra carbon in the atmosphere (leading to acidification of sea water, having increased about 30% in recent decades) and the extra heat in the atmosphere. As seas have warmed, sea levels continue to rise even while atmospheric warming has temporarily slowed. Water expands as it warms, and there have been huge depositions of freshwater from the melting of the Greenland glaciers and most glaciers around the world. The reduction in arctic sea ice (the greatest) and antarctic sea ice secondarily has increased the ability of the high latitude seas to absorb more solar energy and warm, as well. Ice reflects solar energy. Dark sea water absorbs it. Global warming has been greatest in the Arctic region, just as climate models have predicted. At some point, the ocean’s capacity to absorb heat and carbon will begin to level off, and atmospheric warming will begin to accelerate again. The “spikey” appearance of global average temperatures can be easily observed in this graph: http://www.ncdc.noaa.gov/sotc/service/global/global-land-ocean-mntp-anom/201201-201212.png

One more basic: the evidence that human activity is responsible for the majority of global warming is overwhelming. There are more than 20 climate models, each of which can be run with different initial conditions. Every one of them when run with CO2 levels as they were known to be around 1900 show the world would have been cooling since that time. Even when natural warming forcing agents (solar input, for example) are maxed out during this time span up to the present, it is now known the globe would have been cooling on average without the human induced increase in greenhouse gases. In other words, the earth’s natural cycle at this time in its history would have been to enter a cooling period, were it not for us. Those who say “man is too puny to affect the climate” simply don’t grasp the basic, proven physics. Of course, the ultimate runaway greenhouse gas planet–with no help from civilization–is Venus. Its atmosphere is more than 90% CO2, and its surface temperature is over 900 degrees F–hot enough to melt lead. While there is zero chance than can happen here, it should at least demonstrate to those that CO2 is quite a greenhouse gas. Even strong denialists who have the mistaken idea we cannot really impact climate should at least notice the urban heat island effect. Urban areas have significantly higher temperatures day and night because of the absorbing and retaining of solar heat in concrete and pavement. On a clear night, my car themometer often drops 10-13 degrees by the time I get to my suburban home in a more rural section of my town compared to the temperature of north Buffalo. Because man’s urban heat island effect is so strong, these urban temperatures are NOT included in global temperature averages, so as not to skew the data.

Thanks for reading this far. I wanted to write this while the material is still fresh in my head. If this topic doesn’t hold much interest for you, feel free to comment on the weather. “Climate is what you expect. Weather is what you get.”


Summer Makes an Appearance Just About on Schedule

June 16th, 2013 at 9:06 pm by under 4 Warn Weather

After unsettled conditions at the start of the week, we will get into a drier stretch of weather which (at the time of this Sunday night posting) should extend from at least Tuesday afternoon into Saturday. Following passage of a cold front, temperatures will be on the Seasonably Cool side into Wednesday evening. A large ridge of dry high pressure will bring us abundant sunshine Wed-Saturday (excluding nights! :) ). Readings will begin to move back up on Thursday, and go above average on Friday into Sunday. During the weekend, humidity will increase, and a few Shwrs & Tshwrs will begin to come back into the picture, possibly Saturday night and more likely on Sunday.

Following this peak warmth, temperatures will become more moderate again, as the warm ridge of high pressure begins to drop away from us. Most ensemble means show the peak ridging and warmth returning to the western US, but these means only allow modest cooling in the Great Lakes which would bring temperatures back to near normal, rather than below normal/average. It’s difficult to discern whether or not our precipitation will go back to above average during that transition. But it does appear our Tue afternoon-Saturday dry “spell” will help get some meaningful evaporation going in the muddy fields.


June Continues to be a Downer, Following a Very Warm May

June 11th, 2013 at 10:49 pm by under 4 Warn Weather

In the mean, the pattern will continue to favor below average temperatures and above average precipitation for the Great Lakes and nearby regions. We will  have a ridge of high pressure over the west central US, with a trough in the west and a trough over the NE. That favors a NW flow at mid levels of the atmosphere which will deliver disturbances and relatively cool temperatures.

However, it should be remembered that this is a Mean pattern to which I refer. It doesn’t mean we won’t get some warmups and some drier periods in the 2nd half of the month. But when a Mean is so well established, it’s hard for a fundamental pattern shift to gain traction with higher soil moisture and the resulting cooler boundary layer/near surface temperatures.

At the time of this posting–Tuesday night–it still appears a strong (for mid June) area of low pressure will do its worst in the Ohio Valley & PA, rather than in our viewing area during late Wed night into Thursday morning. This storm system will probably spawn a complex of long-lasting violent tstorms Wednesday night. The modeled most likely position of this low would steer such a complex (which may become a powerful derecho (http://www.spc.noaa.gov/misc/AbtDerechos/derechofacts.htm) from Illinois into PA and possibly parts of VA. We will be monitoring this storm system, in the event there is a northward shift in its projected path.

We will be drying out during a Cool Friday into a lovely Saturday. Sunday holds some question. One NWS global model (known as the GFS/Global Forecast System) brings showers into WNY during Sunday, giving us only one nice weekend day. However, the usually (not always) superior European global model keeps us dry through Sunday. Owing to its superior performance, I will go with the European on this Tuesday evening for next Sunday. Either way, even if we get 2 great weekend days there are still no signs of an extended dry period or true summerlike heat returning anytime soon.


It Usually Follows that June will be Milder than May, but….

June 3rd, 2013 at 1:59 pm by under 4 Warn Weather

Obviously, the heat is gone this week. But there are signs that June may end up being cooler more often than the very warm May we just finished. Certainly, there will be warm periods, but the overall pattern and another oscillating pattern favor more frequent troughing over the midwest and the NE, with the strongest/warmest ridging staying over the SW. That is a mean, and will be interrupted to be sure by variations in the pattern. But if this mean were to verify, it also would favor a wetter than average month. Having said all this, it’s only June 3rd as I post this…so much of it is subject to change.

Later this week, tropical moisture is likely to sweep up from the Gulf and SW Atlantic into the east & NE, with some of it arriving in bits and pieces before Thursday morning, and increasing into Thursday-Friday. There will be occasional rounds of showers & tshowers. Currently, the heaviest rain is likely to fall just east of us, but that’s cutting it a little close. Abundant cloud cover should keep instability limited, which makes severe tstorms unlikely. Some of this wet period may linger into a portion of Saturday, with Sunday being the nicest of the 2 weekend days. Another area of low pressure will begin to increase the likelihood of scattered showers by Monday afternoon. Some overall moderation in temperatures should be setting up by mid month. But as of this posting, there are no signs of a return to mid 80s-type heat in the ensemble means.


After a Stretch of Warm, Humid, and Unsettled Days, the Holiday Weekend Looks Cool.

May 20th, 2013 at 12:27 pm by under 4 Warn Weather

As our airmass draws higher dewpoints into the region, the trigger mechanism for any tshowers on Monday afternoon will be the edge of a weak Lk Erie breeze over the hilly terrain well inland to the S & SE. There will be several rounds of convection Tue-Wednesday night, with the atmosphere ripening for somewhat more widespread coverage, especially later Tue and Wed. Winds aloft will be fairly weak, meaning tshowers & more vigorous tstorms will tend to be slower-moving. A few spots could receive gullywashers and experience poor drainage flooding. In addition, this will be our first stretch of Sticky Days and Nights, lasting into Wednesday evening. SPC has WNY at Slight Risk for Severe on Wednesday. Some of that risk will depend on how much destabilization we do or don’t get from solar heating. Modeled profiles suggest some low level directional shear on Wednesday, with winds veering from SSW to SW with increased height. Still, the models as of Monday morning don’t suggest a particularly potent setup…we’d need some less than likely widespread sunshine and a little more shear than what’s expected as of this Monday AM to make things really pop.

By Thursday, we’ll be on the cooler side of this wavy front, with scattered showers. Cool & Dry air will move in for Friday, with daytime highs only in the low 60s and not much warmer on a bright & sunny Saturday. We should be back to the mid and upper 60s by Sunday, and getting closer to 70 for Memorial Day. I can’t rule out some patchy valley frost Friday and/or Saturday night.


This Warmup Won’t Have Sailing Quite as Smooth as the Last

May 13th, 2013 at 10:41 pm by under 4 Warn Weather

After the frosty start to this week, a warm front will arrive in WNY by Wednesday AM, ushering in some Sct Showers & Tstorms. This will be elevated convection, so it will not be impacted by the cooler lake waters. The models for wind directional change with increased altitude show quite a bit of low level veering/wind shear, so some thunderstorms with rotation can’t be ruled out. After one or 2 rounds of Sct convective cells into early Wednesday afternoon, things should settle down for a few days, with daytime highs averaging in the low 70s. The chance for Sct convection will probably return by Sunday into Monday and Tuesday. The airmass at that time will be warm and instability will be on the increase. An upper level trough may take on an orientation (negative tilt showing in some ensemble means) which would increase advection of warm & humid air and help create better dynamics for strong tstorms by Tuesday. A cold upper level low well to the NW of the surface low will feed cold air aloft and create more impressive lapse rates.

It’s VERY early in the game, but this kind of pattern can be recognized as one which can increase the chance for severe tstorms over parts of the Great Lakes.