Arctic Blast Expected Next Week

This winter has been a mild one for much of the eastern half of the country.  In fact it has been well above normal in areas traditionally cold.  The mean temperature in South Carolina has been generally from 4 to 5 degrees F above normal for December.

The mean temperature and anomalies for December through the 26th.  Image credit: NOAA/CPC.

The outlook for this winter was for warmer than normal temperatures in South Carolina and drier than normal conditions.  This was primarily because of the La Nina that formed in the Pacific tropical region.  We had a La Nina last year and it was colder than normal.  The difference has been the Arctic Oscillation.  Last year it was in a negative phase which allowed much of the cold Arctic air to move south.  This year it has been in a positive phase which has kept the bitter cold air bottled up in the polar regions.

Now there is about the be a sharp change in the weather pattern albeit brief.  The upper-level jet stream will dip far to the south early next week.  This will allow an arctic air mass to plunge south into the nation's mid-section over the weekend.  The weather will be fine for South Carolina through New Years Day.  However, a strong cold front will pass through the state Sunday night.

It is expected to be a dry frontal passage.  However, windy conditions are expected for Monday and Tuesday as the cold air rushes into the Midlands.  High temperatures will be in the low to mid 40s on Tuesday and low temperatures will be in the low to mid 20s by Wednesday morning.  Some of the low-lying areas may see temperatures in the upper teens.

Forecast of surface temperatures valid 7 a.m. Tuesday, January, 3,2012.  Image credit: WSI.

This will be the coldest outbreak for South Carolina so far this season.  Now is the time to prepare for its arrival.  Pets and plants will need protection from the cold weather.  Pets have not had enough time to acclimate to such conditions.  In addition there is likely to be a considerable wind chill Monday night.  Wind chill temperatures could be in the teens Tuesday morning.

The European Centre for Medium-Range Weather Forecasts computer model began suggesting this two days ago.  Today all of the computer models are essentially in agreement with a few minor differences.  Thus, confidence is moderate to high in the forecast.  There will likely be refinements in the forecast at this time range, but the overall forecast seems clear.

 

This cold snap will be brief.  A warming trend will begin on Wednesday, January 4, 2012, and will continue through the next weekend.  The unseasonably mild winter weather will be back for the weekend.

Max Storm Doppler Radar

The day after Christmas saw the unveiling of our new Doppler Radar display.  What is this and why is it important?

It may be hard for some of you to get excited over new technology.  When a kid gets a new video game as a present, he can't wait to get to it.  Parents are left scratching their head wondering what is the big deal.  At least he is happy with the new game.  Meanwhile, the kid is conquering the world with the new game.  He gets it.

This new version is a significant upgrade to the current technology.  We decided to call it Max Storm Doppler Radar since the entire graphics suite is Trueview Max.  In reality almost all weather radars are Doppler radars now.  The transformation began in the late 1980s and was almost completely changed by 2005.  What is different is how the data is handled from the Doppler radar.

Thus, this is a software upgrade to our weather computers.  The presentation has a higher resolution, can display up to five live radars, offers greater analytical capabilities, the user interface is better, and is encompassed in one computer system.

Mother Nature was kind enough to provide us with a realtime test of the system this morning as a band of storms raced across parts of South Carolina.  Yes, there were some system failures and minor bugs to correct, but rarely has a new system come under fire so quickly after going operational.  The system is now performing better in less than 24 hours and I think it is surpassing our expectations.

Can I list all of the advantages of the new system? No. Like any new toy there is a learning curve, which is why this mornings' storms were important to us.  There is nothing like "trial by fire".

There are differences in the display which are obvious when comparing with the older Doppler display.  You can still see the older display on our digital channel 19-2.  This channel will continue to feed the radar using the older display, but it will be uninterrupted.

One of the dramatic differences is with the 3D display.  The older version could display multiple live radars in three dimensions, but in low resolution.  Max Storm Doppler Radar allows 3D displays, but only from one radar at a time.  However, that display is at a much higher resolution which provides us with a more detailed picture of the storm vertically.

Fig. 1 An example of the 3D display from the Max Storm Doppler Radar taken Tuesday morning, December 27, 2011.

The Doppler radars that are used to provide the information are the National Weather Service network of Doppler radars.  This is the most advanced network of Doppler radars in the world.  The network will be undergoing upgrades over the next couple of years to become Dual-Polarization Doppler radars.  Then in the about 5 to 7 years the network will be upgraded again to Phase-Arrayed Doppler radars.  More on these developments at a later date.

On Christmas Past

The light rain that fell across the Midlands yesterday made it the seventh Christmas in a row where measurable precipitation was recorded in Columbia.  If you include the trace amount recorded in 2004 late Christmas evening it is the eighth consecutive Christmas with any precipitation.  Eleven out of the last 15 years has seen some precipitation dating back to 1998.

Thus, the trend has been one of a wet Christmas rather than a white Christmas.

It is like a cruel joke from Mother Nature.  The rain was eliminated by all of the computer models on Friday and it looked like a nice weekend.  Then the models reintroduced rain on the Saturday morning run, but only briefly.  There was not a strong case for rain until the evening run.  By that time most newscasts were over for the day due to the Christmas Eve schedules.

By Christmas morning it was obvious that it was going to rain much of the afternoon.  The rain ended by early evening and skies began to clear.  Both observation stations in Columbia received 0.17 inches of rain.

This is not the first time for a Christmas surprise.  In 2004, it looked like the weather would be fine for Christmas and the day after.  No precipitation was in the forecast.  However, by Christmas morning a winter storm warning had been issued for the Midlands.  A storm system had developed in the western Gulf of Mexico and snow had fallen in Houston, TX on Christmas Eve.  The storm system was pushing east and would bring a mixture of freezing rain, sleet, and snow to the Midlands beginning Christmas night and into the next morning (still not a white Christmas).

The table below is a history of Christmas Day weather for Columbia, SC, dating back to 1887 and was put together by the National Weather Service Forecast Office.  The office is responsible for weather forecasts, watches, and warnings for the Midlands and Augusta areas.

Table 1

Year	High Temperature	Low Temperature	Rain	Comments
1887	45	37	0.02
1888	66	34	0.00
1889	72	51	0.00
1890	51	40	Trace
1891	68	46	0.00
1892	53	28	0.00	2.0 " snow Dec 27
1893	70	48	0.00
1894	67	41	0.00	1.3 "snow Dec 28, 0.3" Dec 30, 5.0" Dec 31
1895	72	46	0.00
1896	40	23	0.00
1897	34	28	0.00
1898	43	41	0.00
1899	50	41	Trace	Trace snow Dec 28, 0.4" snow Dec 31, 0.6" snow New Years Day Jan 1, 1900
1900	56	34	0.00
1901	69	48	0.01	1.5" snow Dec 19, Rained each day Dec 23 through Dec 30 (total rainfall 3.41", 1.95" on Dec 28)
1902	51	32	0.00
1903	61	51	0.79
1904	68	54	0.00
1905	53	29	0.00
1906	37	17	0.00
1907	56	33	0.00
1908	63	46	0.00
1909	49	34	0.40	Trace snow Dec 20
1910	46	27	0.00
1911	50	45	0.02	Rained each day Dec 20 through Dec 27
1912	52	27	0.00
1913	56	41	0.52	Trace snow Dec 31, trace snow New Years Day Jan 1 1914
1914	47	36	0.75
1915	70	38	Trace	Trace snow Dec 20
1916	63	47	0.00
1917	64	40	0.23	0.7" snow Dec 29, 1.2" snow Dec 31
1918	58	38	0.00
1919	48	28	0.00
1920	45	28	0.00
1921	64	44	0.02
1922	67	44	0.00
1923	54	33	0.00
1924	56	35	0.02	Trace snow Christmas Day, Rained 2.69" Dec 24, rained 1.83" Dec 30
1925	52	38	0.00
1926	76	44	0.01	Trace snow Dec 30
1927	45	32	0.00
1928	55	35	0.00
1929	50	24	0.00	Trace snow Dec 22
1930	43	28	0.00
1931	65	47	0.00
1932	74	65	0.26	Rained each day Dec 25 through Dec 31 (total rainfall 1.13") Warmest average temperature (69.5 degrees
1933	72	51	0.18
1934	69	44	0.00
1935	41	25	0.00	4.0" snow Dec 22, Trace snow Dec 28, 0.4" snow Dec 29
1936	68	35	0.00
1937	59	40	0.00
1938	57	35	0.00
1939	54	28	0.00	Trace snow New Years Day Jan 1, 1940
1940	59	50	0.28
1941	59	37	0.86
1942	53	37	0.15	Rained each day Dec 25 through Dec 30
1943	38	28	0.00
1944	69	40	0.00
1945	55	33	1.64	Rained each day Dec 27 through Dec 31
1946	59	40	0.00
1947	38	34	0.81
1948	39	32	0.34
1949	48	35	Trace
1950	58	37	0.00	0.2" Sleet Dec 28, rained each day Dec 26 through Dec 31
1951	61	33	0.00	High temperature New Years Day Jan 1 1952 - 79 degrees
1952	56	44	0.27
1953	40	27	0.50
1954	53	29	0.00
1955	79	52	0.00	Record high temperature for Christmas Day
1956	52	31	0.00
1957	59	42	0.19
1958	46	26	0.00
1959	57	36	0.01	Trace snow Dec 21, trace snow New Years Day Jan 1 1960
1960	58	23	0.00
1961	48	24	0.00
1962	37	32	0.26
1963	56	25	0.00
1964	71	59	0.35	Rained 2.86" Dec 26 - heaviest daily rainfall over holidays
1965	64	40	0.16
1966	47	20	0.00	Trace snow Dec 30
1967	54	26	0.00
1968	47	24	0.00
1969	42	27	0.75	Trace snow Dec 26
1970	51	30	0.02	Trace snow Dec 31
1971	66	36	0.00
1972	55	39	0.56	Rained each day Dec 20 through Dec 25 (total rainfall 2.16")
1973	64	47	0.09	Rained 2.04" on New Years Day Jan 1 1974
1974	76	53	0.07	New Years Day Jan 1 1975 high temperature 75 degrees
1975	59	38	0.23
1976	55	24	0.82
1977	63	38	0.85	End record 6 rainy Christmas Days in a row
1978	59	33	0.00	New Years day Jan 1 1979 high temperature 74 degrees
1979	51	40	0.00
1980	49	22	0.00	Trace snow Dec 26, 0.3" snow Dec 27
1981	49	40	1.17	Trace snow Dec 21, Rained total 5.36" between Dec 21 and Dec 31
1982	77	45	0.00
1983	25	7	0.00	Record low temperature, coldest average temperature (16 degrees)
1984	74	54	0.00	New Years day Jan 1 1985 high temperature 80 degrees
1985	48	21	0.00
1986	59	45	0.00
1987	70	62	0.04
1988	67	36	0.00	Christmas Eve high temperature 75 degrees
1989	44	20	0.00
1990	45	27	0.00	Rain from Dec 18th-31st except on the 25th,26th.
1991	58	30	0.00	Rain each day except Christmas from Dec 22nd-29th
1992	50	27	0.00	Rain each day except Christmas from Dec 20th-31st. Total rain 2.3 inches. New Years Day Jan 1st 1993...high temperature 74 degrees.
1993	49	29	0.01	Trace of Snow and Sleet on Dec 22nd and 2.3 inches of Snow on Dec 23rd.
1994	55	36	0.00	Rain each day from Dec 21st-23rd. 2.6 inches of rain fell on the 23rd...total of 5.02 inches fell through the period.
1995	47	19	0.00
1996	53	28	0.00	Christmas Eve high temperature 75 degrees along with 0.70 inches of rain. Dec 31st, New Year's Eve...high temperature 79 degrees.
1997	65	47	0.00	Rain from Dec 21st-30th except for Christmas Day. 1.65 inches fell on Christmas Eve...rain total 3.39 inches through the period. A trace of Snow fell on the 30th.
1998	40	35	0.30	Rain from Dec 22nd-26th. A trace of Snow fell Christmas Eve and light freezing rain fell on the 26th.
1999	39	23	0.00
2000	41	22	0.00	Sleet reported Dec 28th
2001	46	28	0.00
2002	48	33	0.02	Christmas Eve thunderstorm produced 38 mph winds and a total of 1.54 inches of rain.
2003	48	27	0.00
2004	39	33	T	Trace of sleet fell late Christmas evening. On Dec 26th, a mixture of snow, sleet and freezing rain fell.
2005	64	48	0.49
2006	56	48	0.89
2007	56	33	0.10
2008	69	59	0.08
2009	65	36	3.06	Wettest Christmas Day. Low Pressure dumped between 2-5 inches of rain across the region. This produced flooding across many portions of the Midlands.
2010	51	26	0.07

 Table 1: The information is for the Columbia Metropolitan Airport and provided by the National Weather Service Forecast Office in Columbia, SC.

More rain is expected on Tuesday.  It will likely be the last rainfall for the year and we may not see much if any precipitation for the next two weeks.  Thus, for 2011 precipitation will be below normal and 2012 will start on a dry note.  This is not good for an area already in drought.