Wednesday, January 26, 2011

Central Va is getting a little teaser snow

As a child I hated storms which threatened to dump snow and ice only to leave a litte tease at the end.  Areas north of Richmond are experiencing a couple rounds of 32-34 degree snow showers that may be enough to coat the ground in some areas/
Nation Weather Service Radar
The storm is rapidly moving north.  Snow will end in the Richmond area over the next couple of hours.  I do not see a threat for the type of Nor'easter that hits Richmond hard until after Valentine's Day.

Cold to hit hard before mid-Feb warmup

Stratospheric temperatures in the Arctic strongly indicate that a warm period is coming to warm hearts on Valentines Day.  I fear that the warm spell is a weather pattern reload and not an end to this awful winter.  Between now and then leftover cold air needs to go somewhere!

This European (ECMWF) map depicts what I believe will be a blast of windy cold air late next week.  Take note of the locations of the cold upper level heights predicted for 6AM Saturday Feb 5.
Source: Pennsylvania State Univ E-Wall
Unfortunately for snow lovers the storm track has shifted north meaning that we get the cold and are not well positioned for snow.  It would not surprise me if there was a late February or early March attempt at a Nor'easter but that depends on whether the pattern goes into a reloading mode.

Saturday, January 22, 2011

Why February will be more Moderate

Unfortunately we will need to survive a serious Arctic outbreak to reach a warmer and more gentle period of temperatures.  During the past couple of days the Stratospheric warmth over the North Pole has broken down.  This is usually a precursor to a +AO (Positive Arctic Oscillation) and a retreat of the coldest of the cold air back to polar regions.  The lag time in my experience from this breakdown to the effects here in Central NC and VA is 10-14 days. 
Source: NOAA Climate Prediction Center
Do not break out the tanning lotion and shorts just yet.  This time of year the rising sun angle is one of many variables which warm the heights of the Rockies relatively faster than eastern lowlands. This favors a High Pressure system called the +PNA (Positive Pacific North America) which sets up in the Northern Rockies and tends to funnel continental Canadian air towards the south. 

Therefore the Outlook through mid February is expected to be near average (which should FEEL warm) and feature quite a bit of back and forth as fronts come and go.

Tuesday, January 18, 2011

Will it Snow on Friday? - NO BUT...

It appears that the Global AAM pattern is the key to accepting the forecast solution which takes the low pressure out to sea before any moisture can interact with cold air over Central VA and NC.  Next week I believe we will not be so fortunate as the weather pattern will be very supportive of a mixed precipitation event that could be very serious.

Cold High Pressure is expected to position itself over New England.  Arctic air in this situation builds a wedge east of the Appalachians while moisture from a Low approaching west of those mountains overruns the cold air.  At the surface snow quickly changes to sleet and freezing rain.  A secondary low tends to form near the east coast and take over as a primary storm as it moves northward.

Therefore a scenario that is believable and common in NC and VA classic ice storms appears to be very likely between the 26-28th.

Miller-B storm approaches west of the Appalachians setting off a classic Cold Air Damming
Scenario.  Diagram by Dean Grubbs.

Monday, January 17, 2011

Will it Snow on Friday?

There is some buzz about the potential for a late week snowstorm.  My title has a question mark on purpose because the method of storm delivery is not one that is frequently successful in dropping real snow.  While this winter is certainly not a stereotypical La Nina it does feature the phantom snowstorms and systems which explode in one area but skip another in its path which drive all of us NUTS!!!

IF some model output has merit then an area of low pressure will form along a cold front and move up the coast spreading snow to inland NC and potentially VA.  Here is GFS output from Plymouth State Weather Center.
A pretty decent 5-7" of Snow!
So how does this stack up with reality?  I have big concerns about either the quality of US Models and/or the data being entered into them.  How are we to know if the idea of a storm has merit?

Relative Atmospheric Angular Momentum in the Northern Hemisphere continues to favor high latitude blocking (green and blue) and a southern jet stream in the mid-latitudes (yellow).  Recently momentum has been on the rise particularly in our region's latitude.  This suggests that fronts and storm systems progress more rapidly west-to-east compared to points further north.
Source NOAA Earth Science Research Laboratory
The chart looks ominously like 2009-10!

   AAM is a reanalysis from 3 days ago.  Therefore we have no guarantee that momentum will still be rising late this week which would sweep the storm out to sea.  The European model (ECMWF) seems to believe the system will be much further east.
The low over Florida would move quickly east in this Scenario.
My conclusion is that the question of whether it is going to snow later this week will not be answered with much confidence tonight.

Wednesday, January 12, 2011

What a Dog Treat and the Bible have in Common.

Would you believe that I was inspired by ingredients in Bella's Dog Treats?  Would you believe that someone thinks that a compound called Polyethylene Glycol is great for frequent consumption by a dog?  The chemical has such diverse uses as a laxative and an ingredient in ANTIFREEZE!  The next time you need a laxative compare the labeling between between Polyethylene Glycol and Psyllium Husk based products and see which one has more warnings.

This led me toward a familiar Bible passage.
1 Tim 9-10: But those who want to get rich fall into temptation and a snare and many foolish and harmful desires which plunge men into ruin and destruction. 10 For the love of money is a root of all sorts of evil, and some by longing for it have wandered away from the faith and pierced themselves with many griefs. (NASB)  The links provided by Crosswalk Bible Study Tools will lead you to references to the original Greek.

I had always been taught that "love of money" meant simply on a personal basis coveting money or being too greedy.  A look at the original Greek reveals a deeper meaning and potential life application.

Love is expressed by the original Greek as the transliterated word, Philarguria.  A more literal translation would be "Friend to Shiny Things".  Arguria is based on the word Arguros which is used by the Apostle Paul in the context of the money of that time period; Gold, Silver, and Copper coins.

What happens when the passage is understood in the context of being a consequence of prevalent group behavior?  This is where my dog shines some light on the depravity of valuing money above all things

Once I realized the harmful effects of valuing money above the consumer it was clear how all sorts of evil is causing serious consequences:
  1. My cute dog eating a chemical that is an ingredient in Antifreeze each time she earns a treat.   Who can take pride in producing such a product?  Read the warning labels of laxatives containing this substance to really get mad!
  2. The domination of corn and corn derivatives to produce high carbohydrate, low nutrition, and low cost/high gross margin food.  Is America healthier after decades of processed food?  Can someone be found who will be praised for improving society and revolutionizing culinary excellence in such products?
  3. Pots and pans which scorch, warp or break easy, and some are great sources of dietary teflon.  How many are in landfills?  Ceramic, Stainless Steel, and Cast Iron cookware can be passed along through generations.  What is real wealth? Is there anything which the producers can be proud except their profits?
  4. Cadmium used in toys for ChildrenThe good news is at least one expert thought there was not enough of the toxic metal to lead to Brain Damage.
The forementioned Dog Treats are in the trash can!   We want Bella to live many healthy years.  She will have healthy treats tomorrow.

Is the Siberian Express Coming?

Would you believe that there was fresh snow in 49 states today?  Only Florida lacks snow.  Another sign of interesting times?  Raleigh, NC is also on a trajectory that could place this winter in the coldest top 5!

I find it very interesting that some computer model runs are trying to forecast a positive Arctic Oscillation yet have consistently not been negative enough!  For nearly enough the actual results (black line) has been at or below the range of forecasts.
Source: NOAA Climate Prediction Center
The -AO occurs when Upper Level High Pressure dominates the North Pole thereby reversing the Polar Easterlies and displacing the coldest air to the south.  This feature does not guarantee that we on the Eastern Seaboard will get targeted by the cold because a number of other features like this winter's -NAO to route the air southeast.

Similar to 2009-10 warming in the Stratosphere is maintaining Arctic High Pressure and now that feature has gone to further extremes. The 2 small blue areas consistently preceded warming trends by near 2 weeks.  Notice how the warming now has gone all the way to the top:
Source: NOAA Climate Prediction Center
It has been near the top for several days which means that we should be aware that the coldest air so far this winter is coming south.  Projections of NW US High Pressure (called the +PNA) suggest that we in the East are the primary targets!  Mercifully the NAO is slated to be neutral or even slightly positive for the first time since mid November.  Those projections have been accurate throughout this season.  This means that the cold, while serious is likely to lack a mechanism to hold it in place for extended periods.

This Northern Hemisphere projection based on the European Model (ECMWF) depicts a scary scenario which a mountain of High Pressure in Siberia pushes a strong Arctic Vortex into North America.  Off the West Coast that High is slated to build and move inland giving the cold only one direction to go ... Southeast!   On a hopeful note: this kind of pattern is not stable and will not be long lasting.

Sunday, January 9, 2011

Winter Storm heading East, A Summer Hint?

It appears that much of NC faces a combination of snow and ice.  Local Meteorologist and Weather Examiner, Allan Huffman, forecasts 1-4" of snow followed by .25-.33" of ice.  Therefore we can expect hazardous driving and some down trees and power line.

Keep in mind that the storm is expected to be weakening as it approaches.  In fact Central VA does not appear to be in line for very much snow or ice, less than 4" which is Winter Storm Criteria.  The below Water Vapor image from the University of Wisconsin SSEC shows that the incoming system is very mature with an attachment to the subtropical jet, a dry slot, and a trailing upper level low.

Feeling Cold?  Let's Talk Summer!

As one who is stressed by weather extremes I am not pleased at all to see a similar temperature arrangement as the one which preceded last summer. A cool swath carved by the winter subtropical jet and  heat buildup in equatorial regions.  Keep in mind that 4-5 degrees C above average in that location is a monstrous amount of heat content (kinetic energy) compared to the much colder North Atlantic where the same anomaly is relatively tiny amount.

Therefore, is the Atlantic telling us that we are going to burn again this summer?  I hope not!  Here is the current Sea Surface Temperature Anomaly chart from the Plymouth State Weather Center.

Thursday, January 6, 2011

Of Models and Snow

Yes, there is an opportunity for a Winter Storm (4"+) category snow on Monday and Tuesday.  I will also tell you that the idea of getting buried much deeper than that is also on the table.  Before addressing the storm it is important to gain perspective about computer models.

Models are tools designed to provide possible outcomes from the interaction of known weather and climate variables.  They do not create weather.  As tools computer models actually do not forecast weather, real people do that.  The computer models are also using different algorithms with some performing better in certain situations that others.  Oddly enough the European model, the ECMWF, very accurately forecast the Boxing Day Knockout 3-7 days ahead but lost accuracy once the real system was over land and more data was available.  Other models depend on input of good data to get details about precipitation amounts, system structure, temperatures, and more correct.  The crazy model output leading up to Dec 26 was in my opinion a symptom of poor quality data than model performance.

Therefore let us not cheer model output that looks agreeable.  It is more fulfilling to praise the One who created the great mysterious systems of Weather and Climate which even the world's most powerful supercomputers seem to fall far short in processing.
Job 37:5-6 (ESV)
God thunders wondrously with his voice;
he does great things that we cannot comprehend.
For to the snow he says, ‘Fall on the earth,’
likewise to the downpour, his mighty downpour.
The Snowstorm

The Jan 10-11 system is not one that conforms to my system of watching tropical patterns to identify systems that will out-perform or a dramatic change in weather.  Oddly enough that particular date follows a period of high amplitude!  While I am not accustomed to winter storms following Fall and Spring rules (tropical peaks and valleys, not just valleys) you need to know that I do not see a big Winter Storm as being guaranteed.

I also expect the weekend to become agonizing as the storm comes onshore and its data gets fed to the tools called Computer Models.  My suspicion is that the same quality problems that plagued days leading up to the Dec 26 storm have not gone away.

On Satellite the storm has some interesting features:
  • A large upper level circulation.
  • Connection to a powerful subtropical jet stream which is extremely UNCOMMON in La Nina seasons.
  • Access to an abundance of moisture.
Below is a water vapor image from the University of Wisconsin SSEC. 
Upper Low attached to Subtropical Jet
The idea is that this system will cross the Northern Gulf of Mexico and join forces with the monster Arctic air mass and associated energy to spawn a storm that exits the US near the NC/SC coast.  If this scenario succeeds then there will be plenty of moisture for lots of snowmaking.  Unlike Dec 26 this storm cooperates with the Northern jet stream but does not phase.  IF this occurs then deep snows will affect a broad area of N GA, SC, and NC.  VA could get some in the south but escape a winter storm criteria.

This ECMWF illustrates the scenario very well.  Sometimes that model has trouble with timing systems emerging from the SW US.  If the system is late then the Arctic cold could push the track further south and leave even Central NC out of the running for a big snowfall.  Here is the possible outcome as depicted by the ECMWF.
A Scenario that would lead to deeper snow totals.
Expect more updates this weekend as the situation develops or fizzles out...

Wednesday, January 5, 2011

Last Winter's Supervillain has returned for an Icy Encore!

Stratospheric Warming over the North Pole is really a diabolical mechanism which adds miniscule amounts of heat content to the Polar Regions in exchange for huge 25-50% heat content deficits in the mid-latitudes.   Winter 2009-2010's supervillain, the Negative Arctic Oscillation (-AO), has returned for a solid 2010-11 encore.  Take a look at what is going on over the Pole.  Cool areas offer support for warm periods in our latitude with a lag time of 10-14 days.  Note the one approximately 2 weeks before the warm end to December.  There is a second which should be indicating another brief thaw near Jan 20.
The Arctic Oscillation dives to deep negative in response to stratospheric warming
Source: NOAA Earth Science Research Laboratory
The question of how long the incoming arctic cold will last is up for debate.  For insight I look to Hawaii to check EPO (East Pacific Oscillation) projections and Siberia for WPO (West Pacific Oscillation).  Negative phases strongly correlate to cold, positive brings warmer weather.   A negative WPO (-WPO) is a mechanism which funnels Siberian air over the Pole into North America.

Both ensembles forecast a +EPO beginning near Jan 17 which would lead to a warm southeast ridge about 3 days later.  NCEP is more aggressive with next week's cold and following warmth BUT leaves a -WPO.   ESRL is not as aggressive with either projection and does not promise a powerful warm-up either.  
Source: NOAA Earth Science Research Laboratory
My next post will address the likelihood of double-trouble next week in the form of a snowstorm followed by late week ice.  Personally I hope that the ice does not pan out but it fits the weather pattern.

Saturday, January 1, 2011

Revised Winter Outlook: Have we yet begun to shiver?

Job 37:10 From the breath of God ice is made, And the expanse of the waters is frozen. (NASB)

My previous outlook (part I and II ) seems to have been on the right track in terms of concerns for a nasty cold outbreak and a season remembered for its misbehavior.  Unfortunately the well known warm signals seemed to obscure the fact that the "cold outbreak" has no encompassed nearly all of December and is poised to return in January.  Perhaps my experimental idea regarding hurricane paths and potential winter implications could have some merit?

I have been concerned that there may be no current means to accurately predict winters like 1935-36 (Raleigh's snowiest on Record) and the legendary cold 1976-77 (coldest on Record).  The 1976-77 season is known to have occurred despite what would statistically correlate to a mild winter based on Low AAM, La Nina, and a Cold PDO. It is known that High Latitude blocking patterns like the Negative North Atlantic Oscillation (-NAO) were the dominant climate players.  Below is how a -NAO correlates with winter temperature anomalies.  Keep in mind that the orange areas (positive correlation) will be cold when the NAO is negative.
The negative NAO and AO (Arctic Oscillation) patterns are reloading for January.  By mid-month we will be under siege once again by Arctic air that will be colder than what we experienced in December and more extreme compared to averages.

One seemingly unlikely clue that extreme cold is coming is the relationship between Australia and our weather.  Last year the northern portion of the country was  nearly drowned by a their rainy season (despite El Nino).  This year's deluge has affected over 200,000 people and is described as a flood of Biblical Proportions

Larry Cosgrove, WEATHERAmerica,  has demonstrated the synergy produced when convection in the W Pacific interacts with the Jet Stream.  A chilly result of the partnership is the propulsion of Siberian air over the pole into N America and associated extreme weather.  The relationship is clearly seen below.
Pineapple Express usually associated with El Nino races across Pacific.
Source: Univ of Wisconsin SSEC

Therefore my previous Winter Outlook that did not take good ideas far enough is now null and void.  January is now expected to follow the pattern seen in 35-36 and 76-77 and be worse relative to average.  The good news is that in both cases February was near average and spring came quickly in March and was WARM. Here is an average of Jan 36 and 77.
As one who hates the cold I am not real happy about forecasting it.  Could it be that we are reaping the effect of the prolonged solar minimum and uptick in volcanic activity?  Next week I will be addressing some of the historic global extremes of 2010-11 and more important!  the stormy weather pattern reaching the eastern seaboard near Jan 7.