**July 2006 NC Weather Review**

**Overview**

July 2006 was fairly typical of the summer months across North Carolina
with respect to both temperature and rainfall. The rainfall during the
month was in part due to typical summertime, diurnal thunderstorm
activity, which often produces highly variable daily and monthly total
rainfall. However, there were two distinct periods in which the coverage
of the showers and thunderstorms became much more widespread and
organized. These periods of enhanced rainfall were associated with slow
moving cold fronts that advanced into the state during the periods of
July 4^th^ through 7^th^, and July 22^nd^ through 25^th^. It was during
these periods that many areas received a great portion of their monthly
total rainfall. The final monthly totals in July 2006 ranged from 1 to 8
inches across the state. The northern and eastern sections were the
wettest areas, where generally 4 to 8 inches were reported. The southern
Piedmont and Foothills were the driest areas, where only 1 to 3 inches
were reported. Rainfall totals from selected stations across North
Carolina for the month of July are plotted in Figure 1.

The aforementioned cold fronts not only brought significant rain, but
the associated enhanced clouds and precipitation brought cooling relief
to the state. Average temperatures generally ranged between 75 and 80
degrees, except 65 to 75 degrees over and near the Mountains. These
readings generally averaged within one degree of the 30 year normal. The
average monthly temperatures from selected stations across North
Carolina are plotted in figure 2.

![](media/image1.png){width="6.9375in" height="3.3541666666666665in"}

**Figure 1. Estimated Rainfall for July 2006. Plotted data was recorded
by National Weather Service observation systems or cooperative
observers.**

![](media/image2.png){width="6.996527777777778in"
height="3.1909722222222223in"}

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

**Details**

**July 2006** **Temperatures**

The monthly temperatures generally averaged slightly below normal across
the northern and eastern sections of the state, and slightly above
normal over the southern and western sections. This temperature pattern
corresponds well with the rainfall distribution pattern. The wetter and
cloudier areas were to the north and east, while the drier and sunnier
areas were to the south and west.

There were only a few excessively hot and humid days, with nothing more
than what is typically expected for the summer season. The very hot (100
degree) temperatures that were commonplace over the southern Plains and
Gulf Coast states were not felt in our state through July. However,
there were quite a few days in which the temperatures reached or
exceeded 90 degrees over the interior of North Carolina. This was
especially true during the middle of the month, when cold fronts did not
penetrate the state. Figure 3 depicts the number of 90 degree days this
year at selected reporting sites in North Carolina.

![](media/image3.wmf){width="5.15625in" height="3.2708333333333335in"}

**Figure 3. The number of days in which selected stations across North
Carolina have reached or exceeded 90 degrees this year (through July
31). As is typically the case, the mountainous areas and locations along
the immediate coast reported the least number of 90 degree days so far
this season.**

The temperatures over North Carolina in July were moderate when compared
to those of our neighbors just on the west side of the Appalachian
Mountains. A strong and persistent upper level ridge of high pressure,
depicted in Figure 4, was responsible for the extreme heat and drought
centered over Texas and Oklahoma.

![](media/image4.png){width="5.997222222222222in"
height="4.643055555555556in"}

**Figure 4. The average 500 MB pattern over the United States during the
latter half of July.**

Since the center of the ridge generally remained situated well to the
southwest of North Carolina during much of July, the mid Atlantic
states, including North Carolina, were occasionally the benefactors of a
cooling northwest flow aloft. This northwest flow aloft allowed several
surface cold fronts to push south into North Carolina, and kept the
blistering heat to our west.

Figures 5 and 6, shown below, depict the daily maximum and minimum
temperatures observed at both Raleigh-Durham (RDU) and Greensboro (GSO)
during July 2006. The dashed lines represent the normal maximum
temperature (red) and the normal minimum temperature (blue). The
significant cool downs associated with two cold frontal passages during
the first and latter half of the month helped temper the heat for
several days.

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

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

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

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

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

**at Greensboro (GSO).**

**July 2006** **Precipitation**

The monthly rainfall totals were graduated roughly from north to south.
There was a maximum of rainfall of 6 to 9 inches (150 to 250 percent of
normal) across several areas near the North Carolina and Virginia
border. On the other hand, there was a minimum of rainfall observed over
south central portions of the state, which encompassed portions of the
southern Piedmont and Sandhills. Rainfall in these areas averaged only
between 1 and 3 inches (30 to 50 percent of normal). King (Stokes
County) totaled 9.32 inches for the maximum amount in the state, while
Monroe (Union County) reported a state minimum of only one inch.

The July 2006 rainfall came largely from locally heavy thunderstorms,
which produced wide variability in the rainfall distribution across the
state. There were two distinct periods in July when thunderstorms became
widespread. These periods of enhanced convection were associated with
cold fronts that moved slowly from north to south across the state
during the periods of July 4^th^ and July 7^th^ and July 22^nd^ and July
25^th^. The majority of the July monthly rainfall occurred during these
periods at many reporting stations across the state. Raleigh-Durham
reported 3.31 inches of rain during July. Of that total, 1.06 inches
fell on July 6, and 1.61 inches was reported on July 25^th^. Roughly 80
percent of the July 2006 rainfall total at Raleigh-Durham occurred on
those two days alone. Similarly, Greensboro totaled 6.72 inches for the
month. Nearly 50 percent of that total (3.22 inches) fell on one day
(July 22).

Figure 7 is a comparison of observed versus normal rainfall for selected
NWS sites across the state. Of note were the relatively wet conditions
across the northern sections (Mount Airy, Greensboro, Elizabeth City),
and dry conditions over the southern sections (Fayetteville, Lumberton,
and Wilmington).

![](media/image7.wmf){width="5.583333333333333in"
height="3.8020833333333335in"}

**Figure 7. Comparison of observed precipitation and normal
precipitation for July 2006 at selected locations across North
Carolina.**

**Severe Weather during July** **2006**

July was an active severe weather month across the state. There were
several days in which pulse type severe thunderstorms produced large
hail and damaging winds. The most significant events occurred in central
North Carolina on July 4-5, July 15, July 19, and July 27.

Figure 8, shown below, is a picture taken at the reopening of
Fayetteville Street in downtown Raleigh. The view is from Fayetteville
Street looking north toward the Capitol Building, at around 800 PM in
the evening of July 27, 2006. There was a large cumulonimbus cloud in
the background, which was dumping heavy rain over portions of Vance and
Granville Counties at that time. Although the cloud looked ominous, it
remained dry over downtown Raleigh that evening. As was the case during
many evenings during July, isolated thunderstorms brought cooling heavy
downpours to a select few locations.

![](media/image8.jpeg){width="4.1875in" height="5.6in"}

**Figure 8. Photograph taken at the reopening of Fayetteville Street in
Raleigh during the early evening of July 27, 2006. The view is** **from
Fayetteville Street looking north toward** **the North Carolina State
Capitol Building. A large cumulonimbus cloud observed in the background
was dumping heavy rain well north of downtown Raleigh. Photo courtesy of
Jonathan Blaes.**

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

The temperatures during July generally averaged slightly above the 30
year normal for central North Carolina reporting stations. Greensboro
averaged 0.9 degree above normal, while Raleigh-Durham averaged 1 degree
above normal.

Figure 9 illustrates the annual monthly temperature departures from
normal at Greensboro and Raleigh-Durham. Ten of the past twelve months
have been warmer than normal at Greensboro and nine of the past twelve
have been warmer than normal at Raleigh-Durham. December 2005 and May
2006 have been the only months in the past year that averaged
significantly cooler than the 30 year normal.

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

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

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

Wet conditions in July continued the recent wetter than normal monthly
trends over portions of northwestern and eastern North Carolina. The
drier than normal rainfall totals over portions of southwestern North
Carolina continued the recent trend of dryness there.

The 3.31 inches of rain recorded at Raleigh-Durham in July was 0.98 of
an inch below normal. This was the 4^th^ time in the past 6 months that
RDU has recorded below normal rainfall. RDU had a yearly rainfall
deficit of 0.58 inches on July 31. Figure 10 depicts the precipitation
trends at RDU during the past 12 months. The spike in rainfall during
June was largely due to the remnants of Alberto passing over central
North Carolina.

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

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

The 6.72 inches of rain recorded at Greensboro was 2.28 inches above
normal for July. This surplus in rainfall allowed Greensboro to complete
a dramatic turn from a 7.50 inch 2006 rainfall deficit at the start of
June, into a 1.41 inch surplus by July 31. Figure 11 depicts the monthly
precipitation totals and the departure from normal during the past 12
months at Greensboro. Note the huge surplus in rainfall during June and
July after 5 consecutive very dry months.

![](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**

There were short-term agricultural water concerns across portions of the
southern Piedmont and Sandhills in July due to the lack of rainfall.
Otherwise, most crops elsewhere had adequate rainfall this month. Soil
moisture and stream flow levels generally remained unchanged throughout
the month, with the exception of several instances of minor flooding of
fields and small streams across the northern Piedmont and Coastal Plain.

Although drought was not a concern for most areas, the southwestern
third of North Carolina was classified in a moderate drought at months
end. The abnormally dry classification reached as far east as the
western and southern Piedmont and Sandhills by August 1. Figure 12 is
the US Drought Monitor of North Carolina as of August 1, 2006. Much of
northern and eastern North Carolina was generally drought free for the
second month in a row. Many of the reservoirs that supply water to major
metropolitan areas of the Triad and Triangle regions maintained nearly
full pool levels through July.

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

![](media/image12.png){width="5.072916666666667in"
height="2.9270833333333335in"}

**Figure 12. North Carolina Drought Monitor as of August 1, 2006. Note
that drought conditions were only observed in the southwestern portion
of the state.**

**Climate Outlook for the fall 2006**

The Climate Prediction Center released the most recent 3 month climate
outlook recently. Details concerning this forecast can be found at the
web address below\...

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

According to outlooks from the Climate Prediction Center, there were no
signals supporting either above normal or below normal rainfall over
North Carolina this fall. An active Atlantic basin tropical season is
still expected; and recent trends indicate an enhanced probability of
above normal rainfall for Florida. If remnant tropical systems or actual
tropical systems affect the state during the fall, flooding will become
a serious concern in that part of the country.

Figure 13 depicts the latest U.S. Seasonal Drought Outlook. Abnormally
dry areas of western and southern North Carolina are expected to show
improvement through the fall season. It is quite possible that most of
the state will be drought free before the end of 2006.

![](media/image13.png){width="5.625in" height="4.34375in"}

**Figure 13 is the U.S. Seasonal Drought Outlook from NOAA. Improvements
in the recent drought over North Carolina are expected to continue in
the next few months.**

**NC Weather Review Team**

Phillip Badgett

Michael Strickler