The
Climate Prediction Center (CPC) issues outlooks for the next month in the
middle of the current month. They will
often issue an updated outlook near the last day of the current month. Usually these projections do not vary much,
but this month saw a substantial revision.
Computer
models designed to forecast daily weather are run out to 15 days, four times
each day. Most are familiar with the
7-day forecast. The CPC also issues 8-14
day outlooks for the second week of the forecast in additions to the monthly
and seasonal outlooks that they make each month.
Beginning
with the 8-14 day temperature outlook on February 21 and the one issued on
February 28, it seems that the first half of March would be colder than normal
for South Carolina as seen in the outlooks below.
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| The 8-14 day temperature outlooks. The first one made February 21 and the second one (right) made February 28. Click on the image for a larger view. Image Credit: NOAA/CPC. |
The
reason for this projection is that the Arctic Oscillation (AO) has been in a
negative phase with the forecast for it to become strongly negative next
week. This usually produces a cold
outbreak for parts of the U.S. Last year
the AO was strongly positive and the U.S. saw the warmest March on record.
The
initial outlook for March 2013 made in mid-February was for warmer than normal
conditions over much of the eastern half of the country. The persistence of the negative phase AO has
changed the outlook to one where it could go either way. However, the areas forecast to be below
normal were not changed much.
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| The temperature outlook for March 2013. The left one was made on February 21 while the right one was made on February 28. Click on the image for a larger view. Image Credit: NOAA/CPC. |
Thus,
South Carolina is likely to see colder than normal temperatures for the first
half of March. The month is a transition
month from winter to summer, thus you expect a significant warming during
March. However, this year the warming in
the latter half of the month may not completely overcome the cold conditions of
the first half. It is prudent to expect
that the latter half of the month will be warmer than normal, but the month as
a whole will be near normal or slightly warmer than normal.
February
proved to be a very wet month for South Carolina. What does the outlook say about precipitation? Originally the outlook was for it to be drier
than normal, but the new outlook projects equal chances of dry or wet. More than likely it will be near normal.
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| The precipitation outlook for March 2013 made February 28. Click on the image for a larger view. Image Credit: NOAA/CPC. |
This
would be good news for gardeners and farmers.
Near normal rainfall will help keep the moist conditions from February
and make it better for planting in the spring.
We are still in a drought, but it has eased. It is the ground water that will benefit from
additional rains.
