Mother Nature Adds an Extraordinarily Gorgeous Northern Light Show To This Autumn's Color Season!

A spectacular northern lights show extended far south across the sky over the U.S. Monday evening, October 24th 2011. After Mom Nature did her usual beautiful leaf painting this autumn, she added a big bonus by painting the sky with vivid brilliant reds and greens with a teal shade. Just take a look at this picture (compliment of Lake Superior Photo) of the heavens on Monday night October 24th, 2011!

This shows the sun is active with solar activity and the number of solar flares is on the increase the past few years as we climb up the new solar cycle. I talk more about the controversy of solar cycles affecting the weather on the planet in the Winter Outlook.

In the meantime, see Northern Lights from the AP for more information on this event.

Record Low Pressure in Detroit for October Likely Established and Breaks a 118 Year Old Record !

On my blog yesterday I mentioned this current storm was projected to come close to the record low pressures for Detroit in October: At 3AM EDT this morning (10/20/11), Detroit's sea level pressure fell to 29.08" /985 MB/ which according to my records is the lowest pressure ever recorded for the month of October at Detroit! Just last October, a more powerful storm and very intense low pressure moved through the upper Midwest and set numerous record low pressures for that region. While the pressure was also low at Detroit, it did not eclipse the record low pressures for October when it fell to 29.24" on October 26th, 2010.

From yesterday's blog

"She's a beaut' of a storm and note its placement late Wed evening on the12z 10/19/11GFS with a projected central pressure of 988MB /29.22"/ in or near SE Mich. The record low pressure for Detroit in October was way back on 10/14/1893 in an intense low pressure of 985MB /29.09"/.  In more modern times, back in La Nina Fall (which ran from JJA 1970 – DJF 1971/72 & ONI of -1.3) on 10/16/1972, the pressure crated to 985MB /29.12"/ for the second lowest pressure at Detroit. Of course, remember these readings don't have to necessarily denote the central pressure of that particular storm since the center of the low pressure didn't have to pass right over Detroit. We will have to see how low the pressure actually gets at DTW.  Mother nature does seem to have a preference toward spinning up the deepest storms for October in Southeast Lower Michigan during mid month.;-)"

Peak Fall Color Nears in Southeast Lower Michigan Will Mother Nature Spoil the Show? Yes (and Update on the Latest Storm To Do It)

               Written by: William R. Deedler, Weather Historian SEMI - 10/12/2011       

/*Latest Update - 10/19/2011/

Fall leaf color is basically caused by lack of sunlight and to a lesser extent is influenced by the September and October weather. Drier than normal weather late in the summer into early fall will tend to accelerate the leaf changing process, causing the leaves to fall prematurely. Likewise, a wet September and October will tend to produce fewer vivid colors and the leaves may also fall earlier due to the rain, wind and storms. The prime weather conditions which are conducive to brilliant fall colors are warm, sun dominant days and cool, crisp nights but without frosts or freezes; such as high temperatures in the 60s and 70s with lows in the mid 30s to around 50 or similar to the our Indian Summer or Indian Summer-like weather (depending on location) experienced recently. 

 

These sharp, daily temperature swings and more importantly, the decrease in sunlight, play vital roles in the development of the leaf color. This combination of weather and lack of sunlight, creates a blocking effect on the sugars which are manufactured in the leaves and keeps them from reaching the root system. Eventually, these sugars convert to pigments that produce the vivid and brilliant colors seen on many trees in the fall. Evidently, the green chlorophyll in the leaves begins to fade during the shorter fall days with subsequently, less sunlight. Thus, the other color pigments already in the tree leaves are exposed come out and produce the fall color splendor. The yellow color seen in some leaves is created by the xanthophyll pigment, while the orange-red color is caused by the carotene pigment and the red-purple color can be attributed to the anthocyanin pigment. 

 

While color peak may vary season to season across Southeast Lower Michigan, generally the maximum leaf color occurs during the second and third week in October.  This appears to be close to schedule with the trees changing quickly now and most likely will peak about the third week of the month (or approx the 18-26th).  Unfortunately, it looks as though the beautiful gorgeous weather of the past ten days or so is on the wane, because of rain and waves of colder weather. For the next week or so, periods of wet weather along with progressively colder temperatures will spoil our peak autumn color season at least, somewhat. This next weekend will be nothing like last weekend with damper, breezy and colder weather to hold sway over Southeast Michigan. Best chance for rain will be late this week. Parts of the weekend may be salvageable for color viewing but the wind may screw that up too. 

After, early indications are that the models intimating another more powerful cold air mass to blow into Southeast Lower Michigan by mid-late week /18-21^st/ and this would follow the trends written in the Outlook. Preliminary indications a cold rain should move across the region sometime Tuesday into Wednesday with brisk wind conditions and unfortunately, this lousy weather will accelerate leaf drop. At their coldest, highs should be in the 40s to around 50 with lows in the 30s (some 20s are even possible if we clear out one night and winds decouple by the weekend). Normal highs at this time are in the upper 50s to lower 60s while lows fall into the lower to mid 40s.
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*Update 10/19 on predicted storm:

Deep storm with heavy rain and strong winds is on track to affect the entire region through Thursday (for current forecast, see: NWS Southeast Lower Michigan ).

She's a beaut' of a storm and note its placement late Wed evening on the12z 10/19/11GFS with a projected central pressure of 988MB /29.22"/ in or near SE Mich. The record low pressure for Detroit in October was way back on 10/14/1893 in an intense low pressure of 985MB /29.09"/.  In more modern times, back in La Nina Fall (which ran from JJA 1970 – DJF 1971/72 & ONI of -1.3) on 10/16/1972, the pressure crated to 985MB /29.12"/ for the second lowest pressure at Detroit. Of course, remember these readings don't have to necessarily denote the central pressure of that particular storm since the center of the low pressure didn't have to pass right over Detroit. We will have to see how low the pressure actually gets at DTW.  Mother nature does seem to have a preference toward spinning up the deepest storms for October in Southeast Lower Michigan during mid month.;-) 

Also just in Wed Aftn 10/19:
Latest GFS model guidance intimates we a not done with these cold October blasts nor storms. Another powerful cold jet core is being suggested on the GFS model diving out of northern Canada and into the Midwest/East next week (and this is not the first model run this has shown up for mid next week). If this happens,  it would open the door for more storminess and subsequent cold air. HOWEVER, the European model is much weaker and further west with this cold air plunge and trough. If this is right, warmer weather will push out ahead of the system with a ridge developing over the East.  So, the fun has just begun! Check back to see how this one plays out too, if this continues to be forecasted. --------------------------------------------------------------------------------------------------------------
After the gorgeous stretch of weather thru October (basically thru the 11th with temperatures averaging some 6-7 degrees above normal and virtually no rain) mid October offers quite a change and things will go downhill fast (at least for awhile). 

From the Autumn Outlook issued early September:
The thing that is worth noting were the sharp contrasting cold snaps that periodically erased the longer warm spells.  However, in spite of those sharp cold snaps throughout the fall, it also should be noted that October and in some years, early November had the best chance to contain some of the nicest weather. However, on the flipside, these sharp cold air masses tended to bring the risk of snow and the start of winter as a whole, earlier than on average. 

So, the moral of this fall’s story remains the same:

Enjoy the periodic nice weather & Indian Summers while you get the chance!

La Nina Continues to Strengthen...A Weak to Moderate La Nina for the Winter

La Nina conditions continue to build in the Pacific this Autumn 2011 along with an encompassing negative Pacific Decadal Oscillation. La Nina conditions of course refer to cooler than average sea surface temperatures /SST/ extending in a band from the coast of South America, westward across the central Pacific. A negative PDO /-PDO/ refers to cooler than average general Pacfiic weather temperatures west of the U.S. across the central and northern Pacific west of which, will only aid the La Nina. In April 2008, scientists at NASA’s Jet Propulsion Laboratory announced that while the La Niña was weakening, the Pacific Decadal Oscillation—a larger-scale, slower-cycling ocean pattern—had shifted to its cool phase (negative).

The ultimate maximum strength of this La Nina should be interesting as I've noticed a subtle shift in model projections toward a consensus to the lower end of the plot scale (with the mean or average in weak La Nina territory rather than Neutral). Where it finally lands, in part, will affect our weather patterns this winter in Southeast Lower Michigan and the Great Lakes. Of course, the important wild card, as always, will be the dominant phase of the North Atlantic Oscillation.


  
CPC gave an interesting narration recently on the current La Nina and some of the the individual model projections:

During September 2011, La Niña conditions strengthened as indicated by increasingly negative sea surface temperature (SST) anomalies across the eastern half of the equatorial Pacific Ocean.

Currently, La Niña is not as strong as it was in September 2010. Roughly one- half of the models predict La Niña to strengthen during the Northern Hemisphere fall and winter (Fig. 6). Of these models, the majority predict a weak La Niña (3-month average in the Nino-3.4 region less than -0.9°C). In addition, a weaker second La Niña winter has occurred in three of the five multi-year La Niñas in the historical SST record since 1950. However, the NCEP Climate Forecast System (CFS.v1) predicts a moderate-strength La Niña this winter (between –1.0°C to –1.4°C) and CFS.v2 predicts a strong La Niña (less than –1.5°C), which rivals last year’s peak strength. For CFS forecasts made at this time of year, the average error for December-February is roughly ±0.5°C, so there is uncertainty as to whether this amplitude will be achieved. Thus, at this time, a weak or moderate strength La Niña is most likely during the Northern Hemisphere winter. 

In any event, our new La Nina seems to be chugging along nicely so another moderate La Nina I think is as likely as a weak one (a "borderline" La Nina?;-) 

It will be very important to analyze the latest SST temperature plot and computer projections before I issue the Winter 20011-12 Outlook early November.

Model Trends Agreeing on Great Stretch of Nice Weather Coming Up;-)

Many places across Lower Michigan will see some frost or freeze over this weekend into Monday. Areas that may escape the frost and or freeze will again be around Metro Detroit's heat island, the Lake Shores and where patchy areas of clouds hold on. The brisk fall winds, which are also a hindrance to frost/freezes should gradually abate as we get into the new work week. The weather early to mid week looks like it will improve nicely with time with gradually warmer temperatures along with considerable sunshine and pretty much dry. With a little luck, we may even make it through next weekend (I won't let it rain on my birthday - lol, famous last words). The improvement will largely depend on how fast the upper closed low pressure over the east moves out. Past experience and recent trends suggest it will take its good ole time but still, the weather should improve (warmer) as the week evolves. Above normal temperatures (normal highs in SE Mich for this week are generally lower to mid 60s) will creep back into the picture and fulfill our Indian Summer (or Indian Summer-like) weather criteria by mid week into the weekend.

With time, an impressively strong summer-like ridge of high pressure aloft (heights flirting with 596-600 on European for wx buffs) will translate down to the surface and dominant the region. Both models agree with bringing this mammoth upper level and surface ridge over the region late in the week. The European is slower to give our eastern upper low the boot and that looks like the more likely scenario. We'll see how this forecast unfolds this week and hopefully, the models have a good handle on the general overall pattern evolvement and nothing goofs it up! However, if continues as progged, temperatures pushing up into 80s are not out of the question at its warmest. Records next weekend into early the following week, however, are quite warm (and generally the peak for October) running from the mid 80s to lower 90s. Ironically, just a few years ago in 2007 we topped out at 90 on the 8th at Detroit, 91 /7th/ at Saginaw and 88 /7-8th/ at Flint. The highest records for October are 91 /6th/ and 92 /7th/, back in 1963 at Detroit.

Ideal Indian Summer weather occurs when there has been a killing frost or freeze on vegetation and then a nice, long term warm-up with several days of above normal temperatures, generally gradually hazier weather with mainly dry conditions. Of course every year this does not happen over   Lower Michigan at the same time. Generally, the frosts/freezes gradually make their way south and southeast with time. Areas near the warmer Great Lakes may take a little longer with the lake's moderating affect. In Southeast Michigan, I observed over the decades I worked with the NWS there were usually waves of frosts/freezes that overspread the region from northwest to southeast. The metro Detroit area extending east out around Lake St.Clair and along with the downriver communities south to the Lake Erie shoreline were usually the last to give way to the killing cold. When the balmy warmer winds do return, some areas still haven't had that killing frost/freeze, therefore I think the term "Indian Summer-like" weather suffices here. 

Broadly speaking, most areas in Southeast Lower Michigan have seen some type of killing frost/freeze by the third or fourth week of October but not always. I can recall one or two years where some of the hardier vegetation was still creeping along at Thanksgiving and even early December but that was rare. I recall my roses (protected and along the house) still holding on to a bud or two at that time. Alas, only the plants that are the hardiest of lot continue a little longer as the frost/freeze sensitive plants are almost always wiped out by early-mid November.

Try to get out and enjoy one of the most beautiful times in Michigan!