**April 2006 NC Weather Review**

**Overview**

April rainfall totals generally returned to near normal values across
North Carolina. This happened after one of the driest March's on record.
Several significant rainfall events during the last 8 days of April
allowed several stations to record above average monthly rainfall
amounts. Raleigh-Durham's monthly rainfall total was 2.13 inches above
normal and Asheville was 1.08 inches above normal. The Raleigh-Durham
Airport location recorded their 5^th^ wettest April since records have
been kept in 1944. Other locations did not fair quite as well including
Fayetteville and Mount Airy. Both of these stations ended the month at
1.17 inches below normal.

The April 2006 average monthly temperatures averaged well above normal
(3 to 5 degrees) at most of the inland locations. Greensboro recorded
their 2^nd^ warmest April since 1928 and Raleigh-Durham had their 5^th^
warmest April since 1944. It was not quite as balmy along the immediate
coast and on the Outer Banks, where temperatures only averaged 0.5 to
2.4 degrees above normal from Elizabeth City to Wilmington.

Soil moisture and stream flow levels slipped to near all time record low
values over the Piedmont as dry weather persisted through mid April. The
rainfall during the latter half of the month increased top soil moisture
levels and temporarily increased some of the small stream flows. The
rain was even enough to put a small dent in the long term drought
conditions.

![](media/image1.png){width="5.134722222222222in"
height="2.6145833333333335in"}

**Figure 1. North Carolina Drought Monitor as of April 25, 2006. Note
that severe drought conditions across portions of central North
Carolina.**

Figure 1 is the North Carolina drought monitor as seen on April 25,
2006. The Severe drought classification still encompassed much of
central North Carolina but it had been trimmed back to moderate drought
conditions just to the southeast of Raleigh. Severe drought conditions
did expand southward to include the southern Piedmont around Charlotte.
Moderate drought conditions continued to be observed to the crest of the
Appalachian Mountains.

For the latest information concerning the drought, visit
<http://www.ncwater.org/drought/>

**Details**

**Temperatures**

The average monthly temperatures during April generally ranged between
60 and 65, except a little cooler in the 50s across the Mountains and
northern Foothills. Overall, monthly temperatures generally ranged
between 3 to 5 degrees above normal. The April 2006 average temperatures
are shown below in Figure 2 below.

Warm temperatures dominated nearly the entire month of April 2006.
Greensboro and Raleigh were warm enough to end the month as one of the
top 5 warmest April's on record. Daily high temperatures frequently
ventured into the 80s over the interior part of the state. The hottest
period of the month occurred at mid month (April 13-16), when highs
reached into the 90s at several locations. Fayetteville soared to 95
degrees on April 15^th^ while Greensboro reached 90 degrees, and Raleigh
reached 89 degrees.

There were only 2 distinct periods in which the temperatures were
significantly below normal. Those occurred behind cold frontal passages
during April 9-11 and April 26-30. The latter of the two strong cold
frontal passages was followed by a wave of low pressure that brought an
extended period of rain, low cloudiness, and chilly temperatures. Highs
remained in the 50s over much of the northern Piedmont on April 27^th^.
Raleigh reached only 54 degrees on the 27^th^ which was a record low
maximum for that date.

Although some interior stations recorded their last freezing
temperatures on the morning of April 10^th^; neither Raleigh, nor
Greensboro recorded a 32 degree temperature during April. The date of
the last 32 degree occurrence for the spring season of 2006 can be found
in figure 3 on the following page. The average date of the last 32
degree occurrence is depicted in Figure 4 on the following page as well.

![](media/image2.png){width="6.989583333333333in"
height="3.2291666666666665in"}

**Figure 2. Average monthly temperatures during April 2006 across North
Carolina.**

![](media/image3.png){width="6.989583333333333in" height="3.125in"}

**Figure 3. The last day with temperatures 32 degrees or colder during
the spring of 2006 across North Carolina.**

![](media/image4.png){width="6.997916666666667in"
height="3.1395833333333334in"}

**Figure 4. Average occurrence of the last freeze during spring across
North Carolina.**

Figures 5 and 6 on the following page depict the daily maximum and
minimum temperatures observed at both Raleigh-Durham (RDU) and
Greensboro (GSO) during April 2006. The dashed lines represent the
normal maximum temperature (red) and the normal minimum temperature
(blue). The rather large temperature swings noted at both sites are
typical in early spring.

![](media/image5.wmf){width="5.375in" height="3.1979166666666665in"}

**Figure 5. Daily maximum and minimum temperatures observed during April
2006**

**at Raleigh-Durham (RDU).**

![](media/image6.wmf){width="5.333333333333333in"
height="3.1979166666666665in"}

**Figure 6. Daily maximum and minimum temperatures observed during April
2006**

**at Greensboro (GSO).**

**April 2006 Precipitation**

Monthly precipitation totals generally averaged between 3 and 4 inches
across much of the state (80 to 90 percent of normal). The totals were a
bit higher across the Mountains where between 4 and 6 inches of rain
fell (100 to 125 percent of normal). Totals were lower across the
southern sections from Charlotte east to Fayetteville where the monthly
rainfall ranged between 2 and 3 inches (only 50 to 75 percent of
normal). These precipitation amounts were closer to normal than in
previous months. However, generally below normal amounts across the
state further enhanced the ongoing drought conditions. Figure 7 on the
following page depicts the estimated rainfall for April 2006 from
selected National Weather Service reporting sites.

The first half of the month was dominated by fast moving, moisture
starved weather systems. The overall dry pattern that prevailed during
March and the beginning of April began changed around mid April when
slower moving; moisture laden systems began affecting the state. There
were several significant rainfall events during the latter half of
April.

![](media/image7.png){width="6.989583333333333in"
height="3.3958333333333335in"}

**Figure 7. Estimated Rainfall for April 2006. Plotted data was recorded
by National Weather Service observation systems or cooperative
observers.**

![](media/image8.wmf){width="5.583333333333333in"
height="3.8020833333333335in"}

**Figure 8. Comparison of observed precipitation and normal
precipitation for April 2006 at selected locations across North
Carolina.**

**Current, Semi-Annual and Annual Temperature Trends**

April 2006 went down in the record books as another month with above
normal temperatures at both Greensboro and Raleigh. Above normal monthly
temperatures have been recorded in 11 of the past 13 months at both
Raleigh-Durham and Greensboro. Temperatures have averaged above normal
in 13 of the past 16 months at both sites dating back to January 2005.
Only March, May, and December 2005 averaged cooler than the 30 year
normal. Figure 9 illustrates the annual monthly temperature departures
from normal at Greensboro and Raleigh-Durham.

![](media/image9.wmf){width="5.59375in" height="3.59375in"}

**Figure 9. Monthly temperature departures from normal at Raleigh-Durham
and Greensboro from April 2005 through April 2006.**

**Current, Semi-Annual, and Annual Precipitation Trends**

The dry conditions observed across the state since the beginning of 2006
began to show signs of easing during late April. Very little rainfall
was recorded during the first half of April which continued a rapid
expansion of moderate to severe drought conditions throughout the state.
Widespread rain during the last week of April may have signaled a change
in the dry pattern.

Raleigh-Durham recorded above normal monthly rainfall for the first time
this year. Even with the April surplus of 2.13 inches, the 2006 deficit
was still at 4.42 inches. Below normal precipitation has been recorded
in 7 of the past 12, and 9 of the past 15 months. Figure 10 depicts the
precipitation trends at RDU during the past 12 months.

![](media/image10.wmf){width="5.416666666666667in" height="3.3125in"}

**Figure 10. Semi-annual and annual precipitation trends at
Raleigh-Durham (RDU).**

The rainfall during April at Greensboro totaled 0.72 inches below
normal. Greensboro has been even drier than Raleigh-Durham, as 9 of the
past 12 and 11 of the past 15 months have been drier than normal. Figure
11 depicts the monthly precipitation totals and the departure from
normal during the past 12 months at Greensboro.

![](media/image11.wmf){width="5.447916666666667in"
height="3.3645833333333335in"}

**Figure 11. Semi-annual and annual precipitation trends at Greensboro
(GSO).**

**North Carolina Water Resources Information and Outlook**

The reservoir levels remained nearly steady from February through mid
April even with the lack of rain. The same was not true of the stream
and river flows as they began a decline in mid January and continued to
decline through mid April. The inflow into local reservoirs in and
around the northern and central Piedmont had reduced to a trickle. The
widespread rain during the last week of April created brief rises on
area streams. Yet, the USGS continued to report that stream flows
remained historically into the lowest 10 percentile observed. Additional
widespread rain is needed before concerns that local reservoirs may
again begin a steady decline are relieved. Many local cities and towns
continued the already tightened water conservation and restriction
measures that were instated in late March.

**Climate Outlook for May, June, and July 2006**

The Climate Prediction Center released the latest 3 month climate
outlook recently. Details concerning this forecast can be found at:

<http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/page2.gif>

**90-120 Day Precipitation Outlook for North Carolina through August
2006**

On a much brighter note according to outlooks from the Climate
Prediction Center, the oceanic and atmospheric indicators in the
tropical pacific indicate a rapidly weakening La Niña conditions. This
allowed the CPC to reduce the probability of dry conditions over North
Carolina for the remainder of the 2006 spring season. There were now
equal chances of above, near normal, and below normal rainfall across
North Carolina for the remainder of the spring season.

![](media/image12.png){width="4.623611111111111in"
height="3.582638888888889in"}

**Figure 11 is the U.S. Seasonal Drought Outlook from NOAA. The drought
over central North Carolina and southern Virginia may expand to cover
most of North Carolina and the southeastern U.S. from March through
June.**

**Conclusion**

The rapid weakening of the La Nina conditions favors a return to near
normal rainfall over the southeastern United States including North
Carolina for the remainder of the spring season. The widespread rain
event the last week in April may have marked the beginning of the end of
the current severe drought. However, it will take a sustained period of
above normal rainfall to help the current moderate to severe drought
conditions.

**NC Weather Review Team**

Phillip Badgett

Michael Strickler