**October Number range CHAPTER2005 NC Weather Review**

**Overview**

Significant rain fell across North Carolina during the first week of
October, which brought relief to some areas that had experienced drought
conditions. Unfortunately, the heaviest rain fell along the coast and in
the foothills of the Blue Ridge Mountains, in areas that were not
classified in a drought. This resulted in localized flooding problems in
those areas, but provided no relief for the severe drought conditions
over the Piedmont.

The early month's rain was a fleeting memory by month's end. The dry
pattern that had plagued much of the region since mid summer reared its
ugly head again by the second week of October, and lasted the rest of
the month. Raleigh-Durham, which recorded nearly 2 inches of rainfall
between October 5 and October 8, recorded only 0.14 of an inch between
October 9 and October 31. The lack of rain during the last three weeks
of the month sent local municipalities scurrying to re-implement
mandatory water restrictions (ones that had been relaxed just after the
brief rainy period) due to dropping reservoir levels from Raleigh-Durham
to Greensboro. Figure 1 is the North Carolina drought monitor as seen on
November 1, 2005. Of note are the severe drought conditions over
portions of the northern and central Piedmont of North Carolina, and the
contrasting wet conditions near the coast. For the latest information
concerning the drought visit <http://www.ncwater.org/drought/>

![](media/image1.png){width="5.279861111111111in"
height="2.7083333333333335in"}

**Figure 1. North Carolina Drought Monitor as of November 1, 2005. Note
that first level to severe drought conditions are shown over central
North Carolina.**

Along with the dry weather, the trend of above average monthly
temperatures continued in October 2005. The monthly temperatures
generally averaged 2 to 4 degrees above normal across the state. This
was the sixth straight month of above normal monthly temperatures at
Greensboro and Raleigh-Durham.

**Details**

**Precipitation**

The rainfall totals during the first week of October 2005 were quite
impressive. The heaviest rain, ranging from 5 to locally 13 inches, fell
along the Blue Ridge Mountains, and throughout the coastal area. The
heavy rain produced localized flooding problems. Much lighter rainfall
totals of 1 to 3 inches were common throughout the drought stricken
Piedmont. The rainfall rates and amounts did not create enough runoff
over this region to begin to replenish reservoir levels depleted by the
drought. The rainfall was beneficial; however, as it brought the regions
first general soaking rain since July. Top soil moisture improved
greatly, which led to less water usage for irrigation purposes. Figure 2
depicts the rainfall totals during the first week of the month. Note the
large gradient in rainfall from the coast into the Piedmont, and from
the eastern slopes of the Blue Ridge to the southwestern Smoky
Mountains.

![](media/image2.png){width="7.052083333333333in"
height="3.5590277777777777in"}

**Figure 2. Storm Total Rainfall Amounts from the October 5-8, 2005
Heavy Rain Event.**

The rain was produced by the development of a mid and upper level trough
that extended from the Ohio Valley to the East Coast during the first
week of October. Unfortunately, this pattern that brought the widespread
rain lasted only a few days, and this ended up being the only
significant widespread rain event across North Carolina for the balance
of the month. Hurricane Wilma, after hitting south Florida, was pulled
up the eastern United States seaboard by the large trough. Luckily, the
hurricane remained far enough offshore in the western Atlantic, and
spared the North Carolina coast from another landfall from a hurricane.

The pattern turned dry again across North Carolina after the passage of
the troughs in early October. Very little rainfall was recorded during
the last 3 weeks of October, as most locations had around 0.25 of an
inch of rain or less during the last half of the month. High pressure
ridging along the Gulf Coast States was responsible for the extended dry
weather pattern.

With the return of the dry ridge of high pressure, it was not surprising
that monthly rainfall tallies ended up very close to the tallies that
were recorded just after the first week of the month. Figures 3 and 4
are final October 2005 rainfall totals as observed by the official
National Weather Service observation sites and NWS cooperative
observers. Note that 80 to 95 percent of the rainfall fell during the
October 5-8 rain event.

![](media/image3.png){width="7.15625in" height="3.5625in"}

**Figure 3. October 2005 Estimated monthly precipitation totals.**

![](media/image4.wmf){width="5.177777777777778in"
height="3.2395833333333335in"}

**Figure 4. Comparison of observed precipitation and normal
precipitation for October 2005 at selected locations across North
Carolina.**

**Temperatures**

The month began very warm with average daily temperatures generally 5 to
15 degrees above normal between October 1 and 15. High temperatures
reached the 80s over many inland locations outside of the Mountains and
the immediate Atlantic Coast during the first week. After a brief two
day cool down on October 16 and 17, temperatures returned to the 80s
between October 18 and 20. Finally, a long awaited pattern change
allowed a shift from warm toward much cooler conditions began October
23. This cool pattern lasted through the end of the month, waxing
between October 27 and 30, when the first freeze of the fall season was
recorded at many Piedmont locations. Due to the warmth during the first
half of the month, the first freeze came 1 to 2 weeks later than average
for much of North Carolina. Figure 5 depicts the 30 year average first
32 degree occurrences, or "first freeze" in fall for North Carolina.

![](media/image5.png){width="6.800694444444445in" height="3.14375in"}

**Figure 5. The 30 year average occurrence of the first 32 degrees
"first freeze" in fall.**

October 2005 continued the recent trend of above normal monthly
temperatures across North Carolina. Average monthly temperatures
generally ranged between 60 and 66 degrees, except across the Mountains
where temperatures averaged about 5 to 10 degrees cooler. The average
monthly temperatures across North Carolina are shown below in Figure 6.
These temperatures were generally 2 to 4 degrees above the 30 year
normal.

The warmest readings were reported along the Coastal Area and on the
Outer Banks, including: Ocracoke (66.9 degrees), Wilmington (66.5), Cape
Hatteras (66.2), Jacksonville (65.3), Gum Neck (66.1), and Longwood
(64.9). The coolest readings were found over the higher elevations of
the Mountains, where Mount Mitchell, Mount Pisgah, and Grandfather
Mountain (all at elevations above 5000 feet) averaged 50 degrees or
lower. The coolest average temperature was found atop Mount Mitchell (a
refreshing 47.4 degrees). Populated locations in the Mountains had
temperatures that averaged in the 50's, including Boone (53.8 degrees),
Jefferson (54.7), Asheville (58.5), and Bryson City (59.3). These
temperatures were still generally 1 to 3 degrees above the 30 year
normal.

![](media/image6.png){width="6.923611111111111in"
height="3.173611111111111in"}

**Figure 6. October 2005 Average monthly temperatures across North
Carolina.**

Figures 7 and 8 depict the daily maximum and minimum temperatures
observed at both Raleigh-Durham (RDU) and Greensboro (GSO) during
October 2005. The dashed lines represent the normal maximum temperature
(red) and the normal minimum temperature (blue). The very warm
temperatures during the first and third week of the month are noteworthy
at both RDU and GSO.

![](media/image7.wmf){width="5.000694444444444in"
height="2.942361111111111in"}

**Figure 7. Daily maximum and minimum temperatures observed during
October 2005 at**

**Raleigh-Durham (RDU).**

![](media/image8.wmf){width="5.081944444444445in"
height="3.0506944444444444in"}

**Figure 8. Daily maximum and minimum temperatures observed during
October 2005 at Greensboro (GSO).**

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

October marked the 6^th^ straight month of above normal average monthly
temperatures at both Greensboro and Raleigh-Durham. Temperatures have
averaged above normal in 8 of the 10 months at both sites during 2005.
Only March and May averaged slightly cooler than the 30 year normal.
Dating back to 2004, both Greensboro and Raleigh-Durham have recorded
warmer than normal monthly temperatures in 12 of the past 14 months.
Figure 9 illustrates the annual monthly temperature departures from
normal as observed at Greensboro and Raleigh-Durham.

![](media/image9.wmf){width="5.000694444444444in"
height="3.0506944444444444in"}

**Figure 9. Annual monthly temperature departures from normal at
Raleigh-Durham and Greensboro.**

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

The months of August, September, and October brought very little
rainfall to central North Carolina. Had it not been for the widespread
soaking of 1 to 3 inches that fell during the October 5-8 period,
rainfall during this three month period would have been nearly
non-existent over the interior of North Carolina.

August was characterized by isolated thunderstorms with wide gaps
between rainfalls. Hurricane Ophelia brought heavy rain to the coast in
the middle of September, but little else fell during the month over the
rest of the state. October turned decidedly dry again after the brief
rainy spell, as Hurricane Wilma brought a scare to the North Carolina
coast.

During the quarterly period that included the months of August,
September, and October, Raleigh-Durham (RDU) only recorded 6.78 inches
of rain. The normal during this period is 11.22 inches, which is only 60
percent of normal. The nearby cooperative observer at Raleigh (NC State
campus) received only 5.14 inches during this three month period (only
40 percent of normal). Quarterly rainfall deficits elsewhere in central
North Carolina generally ranged between 5 and 8 inches.

The total precipitation for the calendar year 2005 at RDU (January 1
through October 31) was 29.59 inches. This total was 7.54 inches below
normal. Drier than normal conditions have been the rule at RDU in 9 of
the past 12 months.

![](media/image10.wmf){width="5.46875in" height="3.332638888888889in"}

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

Even more parched during this past 3 month period were areas just to the
west and north of Raleigh, including Greensboro (GSO). This area was at
the center of the ongoing severe drought that had taken stranglehold
over central North Carolina. The August-October rainfall at GSO totaled
a mere 4.99 inches, which was 6.29 inches below normal, or 44 percent of
normal.

The yearly total for 2005 at GSO indicated a net precipitation deficit
of 11.24 inches. Ten of the past twelve months have been drier than
normal. Figure 11 depicts the monthly precipitation totals and the
departure from normal during this period at Greensboro.

![](media/image11.wmf){width="5.447916666666667in"
height="3.365972222222222in"}

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

**North Carolina Water Resources Information**

Severe drought conditions continued to grip the central and northern
Piedmont of North Carolina at the end of October. The rainfall during
the first week of the month only provided very short term relief which
mainly helped in dampening the top soils and with greening up the
backyard grasses. The lack of rain over interior sections during the
last three weeks in October greatly offset the benefits of the
widespread rain early in the month.

Stream flow conditions and local water reservoirs actually became more
depleted as October progressed. The rainfall 2005 rainfall deficits over
the interior of North Carolina reached between 7 and 14 inches by
October 31. The driest conditions and severe drought classification was
centered on the Greensboro to Roxboro to Raleigh-Durham regions of the
Piedmont.

The agricultural concerns from mid summer quickly became hydrological
concerns as summer became fall. The streams, lakes, and reservoirs saw
significant falls. Many locations, including the Raleigh-Durham and
Greensboro regions, implemented water usage restrictions to protect the
diminishing reservoir supplies in mid September. Those restrictions were
loosened after the rain in early October but tightened again as the
conditions turned dry.

2005 rainfall surpluses were confined to areas of the Mountains and
along the Coast of North Carolina. The rainfall surpluses kept the
southeast Coastal Plain, Coastal Area, and Outer Banks out of any water
resource concerns.

![](media/image12.png){width="5.666666666666667in"
height="3.5277777777777777in"}

**Figure 12. The U.S. Drought Monitor as of November 1, 2005.**

**Climate Outlook for November, December, and January 2005**

The Climate Prediction Center released its latest 3 month 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>.

Significant relief from the severe drought conditions should be slow to
come as fall becomes winter. Current indications are that there is an
equal chance of above normal, normal, or below normal temperatures and
precipitation during this three month period across North Carolina. This
means that there are no signals that clearly support a forecast of above
normal or below normal precipitation over central North Carolina as we
move into the winter season.

**NC Weather Review Team**

Phillip Badgett

Michael Strickler