February 22, 2007 Fire Weather Event
Updated 2007/08/15
Event Headlines
...On February 22, 2007, the combination of strong westerly winds, temperatures soaring
into the 70s, very low relative humidity's, and increasingly dry fuel moistures lead
to a critical fire weather situation with adverse fire behavior over central North Carolina...
Event Overview
On February 22, 2007, the combination of strong westerly winds, temperatures soaring
into the 70s, very low relative humidity's, and increasingly dry fuel moistures lead
to a critical fire weather situation with adverse fire behavior over central North Carolina.
There were dozens of fires reported across North Carolina on February 22, 2007 with at least
two fires in central North Carolina that spread out of control and burned several residential structures.
A wildfire in Hoke County spread from a rural area into a
residential neighborhood in Raeford and destroyed
several homes. Another fire occurred in north Raleigh, in the middle of a sprawling
urbanized area, and its initiation was attributed to “improperly disposed smoking materials” in some shrubbery.
The fire quickly spread from the bushes into the town homes. It was so windy, warm, and dry that the
fire jumped from one townhouse row to another.
The image below from the krax WSR-88D Doppler radar shows the smoke plumes from the
larger fires across central North Carolina including the north Raleigh, Raeford
and Harnett County fires.
Synoptic Overview
On Wednesday evening, February 21, 2007 an intense shortwave
trough was located over the far northern Plains. Aided by a
130 kt jet at 250 MB, the
shortwave had moved southeast and was located over the
Great Lakes region at 12Z on Thursday, February 22. Winds behind the trough at 500 MB were in excess of
100 kts while a large area of winds in excess of 50 kts was noted behind
the trough at 850 MB. The associated cold front reached the Ohio and Tennessee Valley
by 12Z Thursday. The bulk of the
clouds associated with the
cold front were confined to the southern Great Lakes and Appalachians.
A dry surface cold front pushed from the Ohio Valley region
into the Appalachian Mountains during the morning hours,
then surged off the Mountains through central North
Carolina during the early afternoon.
The westerly surface winds increased during the late morning hours and became strong and
gusty by early afternoon. The increase in winds was due to the
strong surface gradient
and the deep mixing of the lower portions of the atmosphere up to 750-800 MB
which allowed higher momentum air to reach the surface.
The strong westerly winds,
aided by down slope subsidence drying and warming off the Appalachians, helped spread
very warm and dry air eastward across central North Carolina during the afternoon.
The time section plot at Raleigh-Durham shows the temperatures soared into
the 70s, winds gusted in excess of 30 MPH, and relative humidity values crashed into
the 8 to 15 percent range. A time section plot at
the Fort Bragg RAWS station shows a similar pattern with a tremendous
drop in relative humidity, warm temperatures, and wind gusts around 40 MPH.
At the time of the event, central North Carolina was experiencing abnormally dry conditions.
During the 6 week period prior to the event, rainfall totals were averaging less than 50 percent
of normal rainfall and no rain had been recorded in over a week (rainfall estimates from
January 1-15, 2007 |
January 16-31, 2007 |
February 1-15, 2007).
The 6 week period had also been significantly colder than normal with many subfreezing
nights. This led to a
significant drying of the fuel moisture levels.
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