Tag Archives: forecast

Correlation

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One of the most common questions that come into the weather center deals with correlation.  We are often asked if because this season is – insert hot, cold, dry or wet – does that mean the next season will be – insert hot, cold, dry or wet—and usually the reference is that the next season will be the opposite of what is currently occurring. 

In other words, is there a correlation between what is occurring now and what we can expect in the future?  Our cold spring have many people inquiring if a hot summer is coming as that would then “balance” the weather.  There can be some correlation between seasons, especially when dealing with El Nino or La Nina events, yet even in those instances the relationship is no where near 100% accurate. Therefore, as a general rule a pattern from one season, does not correlate very well with future seasons. 

Meaning, this summer will not necessarily continue to be cold, or end up extremely warm based on what has been occurring these past few months.

Banks Thermometers Hint to the Future

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Bank thermometers will often show erroneous temperatures.  It is not so much that the sensor being used is inaccurate, but instead, the sensor is often placed in a poor position.  To accurately measure the air temperature, official thermometers have historically been placed in a white shelter box referred to as a Stevenson screen and more recently in a white enclosed ventilated plastic cover.

Often a thermometer used by a business is directly in the Sun part of the day, plus the thermometers are often placed over parking lots that are black and absorb much of the incoming solar radiation and make the surrounding air much warmer.  That dark surface influence has been particularly noticeable in recent days as the strong early Spring sunshine has a lot of potential to warm, but our snow pack has been limiting the area from reaching our temperature potential.

So if you see a bank thermometer flashing 50 degrees on a sunny day, the reality is, it would likely really be 50 degrees if it was not for our deep snow cover.

Tragic End

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Back on June 24, 2012 a tornado, associated with Tropical Storm Debby, moved through Highland County, Florida.  Very tragically, a young mother was killed protecting her baby from the violent wind that struck her house.  The baby still wrapped in her mother’s arms suffered broken ribs, cuts and bruises, but did make a full recovery.

That tornado death was the last one reported in the United States until last Wednesday’s severe weather that hit northern Georgia particularly hard.  An EF-3 rated tornado moved through Adairsville, Georgia killing a man when a tree fell on a shed he happened to be seeking shelter in.  That stretch of 220 days was the longest stretch between tornado deaths in the country since such records have been kept in 1950.

The previous record was 197 days which occurred from late 1986 through early 1987.  That period many of you will recall was also a period of drought and the corresponding lack of thunderstorms in the United States.

White

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Last year Fargo Moorhead recorded a brown Christmas.  Other recent brown Christmas’ included 2006, 1999 and 1994.  Our historic average for having a white Christmas is 84%, meaning that approximately once every decade we have no snow on the ground on this morning.   This year we are experiencing a white Christmas.

You may remember that a year ago today, I forecasted a white Christmas in 2012.  It was based on the fact that the odds favored me being right and that locally there has never been two brown December 25ths in a row since such records have been kept.  Although we do not have a lot of snow on the ground, it is close to the historic average of 4 inches for this date.

The extremely snowy Decembers from 2007 to 2010 tended to skew our perception of how white the ground usually is this time of year.  Yet, both the amount of snow on the ground and our total for the season are pretty close to the average.

Evan

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In the Atlantic Ocean they are called hurricanes.   In the western Pacific they are referred to as typhoons.  In the southern Pacific and in the Indian Ocean they are referenced as tropical cyclones.  The tropical cyclone season is just beginning and already one has brought devastation.

Somoa and neighboring American Somoa were hit last week by Tropical Cyclone Evan.   Evan was a Category 2 Tropical Cyclone when it made a direct hit on Upolu, the eastern of the two principle islands of Somoa.  It then moved northeast with the eye wall just missing American Somoa and then it stalled and moved back toward Somoa with the eye wall barely missing them again.  That track kept high wind and torrential rainfall over the area for a few days. Tragically at least three deaths were attributed to Evan with two of those deaths being young children.

The storm then intensified into a Category 4 storm and headed southwest and had major impacts on Fiji on Monday.

Atmospheric Rivers

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Rivers flood.  We know that all too well here in the Red River Valley.  But there is another kind of river that has been causing flooding in California that you may not have heard about, an atmospheric river.  Atmospheric rivers are narrow regions in the atmosphere, often one to three hundred miles in width that contain high concentrations of water vapor.

Like real rivers, they come in all shapes and sizes and often contain meanders.  Using specialized satellite data (water vapor imagery) these rivers of concentrated water vapor are often easily detected.  One type of atmospheric river is the so called “Pineapple Express”.   This references times when tropical moisture near Hawaii is transported into the west coast, but these narrow flows of moisture can also come from non tropical sources and that has been the case with the heavy rain that has been impacting northern California in recent days.

Although these atmospheric rivers can cause flooding, more often they just bring beneficial moisture to the west coast.

No Weather Guarantees

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Certain terms gradually build into the common vernacular.  Each year the new words that are added to the Oxford Dictionary usually make big headlines on local and national news.  In weather, although many terms have been around for decades within the weather community, in recent years, certain terms have become common place in society.

The term Doppler would be a great example of this.  Another term that garners wide use is El Nino (the warming of equatorial waters in the Pacific Ocean).  The National Oceanic and Atmospheric Administration (NOAA) this past summer issued a forecast that an El Nino was likely to develop for this upcoming winter which prompted many individuals to email and talk to me about our upcoming mild winter.  Yet, there are serious doubts if an El Nino will develop (so far it has not), plus as we learned during the 2009-2010 winter, an El Nino is no guarantee of a “soft” winter.

The weather is far more complicated than a fancy term.

That Warm Spring

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The National Climatic Data Center released their climate statistics for both May and the spring season last week.  Although Fargo Moorhead recorded the warmest spring on record, as a whole, both North Dakota and Minnesota ended up with the 2nd warmest spring since 1893.  The lower 48 states overall recorded the warmest spring on record as did a vast majority of the states east of the Rocky Mountains.

The previous year with the warmest spring was back in 1910 and that year still ranks as the warmest on record for North Dakota and Minnesota.  The main difference between these two very warm springs was that in 1910 the warmth was center just slightly north of where it was this year.  That slight difference was enough to keep the local states near, yet short of that record of 102 years ago, but did allow states to our south and east to edge out 1910 as the warmest.

Of note, both 1910 and 2012 were both very unique in the record books for the extreme warmth observed.

 

Spring Outlook

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Once again I was asked by the State Climatologist in North Dakota to write a summary to what I expect for the upcoming season.  What I wrote can be found below.  It can also be found in the State Climate Bulletin to be published soon.

 

Spring and autumns are always the most difficult to forecast because of large swings that can and do occur on both daily and weekly time scales.  Plus, with so much cold elsewhere on the planet, this spring in particular has the potential for giant swings from warm to cold.  These temperature swings can also lead to prolong periods of dry weather intermixed with brief periods of significant precipitation.

Using that as a backdrop, after a mild March that may end up as one of the warmest on record for the region, April looks to be transitioning to colder weather, followed by a near average May.  That would mean, overall, an above average temperature for the season, but we always need to remember, that does not mean consistently above average and a poorly timed cold front can easily hamper the planting season.

Although historically when a La Nina is present is the Pacific, this area has a higher than normal likelihood of recording above average precipitation in the spring, the current La Nina is fading quickly and therefore, the odds favor this season to finish nearer to the long-term average for rain and late season snowfall.  If that forecast holds, it would be a welcome change from the excessive spring moisture many areas have recorded in recent years.

The latest spring outlook from the Climate Prediction Center (CPC) for the next three months can be seen below.The CPC is forecasting a slightly higher than normal probability of above average temperatures and equal changes of above, below or normal precipitation. You can find the current and future outlooks, when new ones become available, athttp://www.cpc.ncep.noaa.gov/products/predictions/90day.

 

Also, the North Dakota State Climate Office has links to the National Weather Service’s local 3-month temperature outlooks for the upcoming year. Those forecasts can be found at:http://www.ndsu.edu/ndsco/outlook/L3MTO.html.

Christmas 2012 Forecast

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This time of year we get many inquiries about travel conditions and the forecast for different spots around the nation.  In the summer it is requests as to what the weather may be for an upcoming vacation or wedding.

Sometimes people get very anxious for these forecasts as we occasionally get asked several months in advance for a wedding forecast from nervous brides wondering if they need to rent a tent or if the sun will be shining on their wedding day.  Of course our ability to forecast accurately beyond a week is very limited.

Yet, knowing that, the lack of snow for Christmas this year has apparently been hard on many people as I have already been asked about Christmas 2012.  So here I go out on a limb; we have a white Christmas 84% of the time, plus, we have never had two brown Christmas’ in a row since records have been kept, therefore, I am forecasting a white Christmas in 2012.  Remember, you heard it here first.

Have a Merry Christmas.