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July 1, 2012 Derecho


Event Overview –

Violent severe thunderstorms swept through Eastern North Carolina during the afternoon and evening of Sunday July 1, 2012,  killing three people – one in a collapsed building, and two due to a falling tree. The deadly thunderstorms were fueled by the extreme heat affecting the Southeast, coupled with unusually high levels of moisture. The extraordinary heat and moisture caused high levels of atmospheric instability rarely seen. The Convective Available Potential Energy (CAPE) in Eastern North Carolina and South Carolina at 2 pm EDT Sunday was 5000 – 6000 J/kg, with a lifted index of -14. The Morehead City NWS office analyzed CAPE levels in excess of 7000 J/kg (Figure 1) in the region, which is a truly rare occurrence.

Figure 1. Convective Available Potential Energy (CAPE) at 3 pm Sunday July 1, 2012

This derecho came on the heels of a stronger derecho event that affecting much of the mid-Atlantic states, and Washington DC in particular, just two days earlier on June 29. A derecho is defined as a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. Although a derecho can produce destruction similar to that of tornadoes, the damage typically is directed in one direction along a relatively straight swath.  They often form along the northerly boundary of a hot air mass, right along or just south of the jet stream - where upper level winds zip along at high speeds. The Derecho Composite Parameter (DCP) (Figure 2), developed by the Storm Prediction Center, showed a high likelihood for this type of system to affect eastern North Carolina on July 1. The DCP was developed to identify environments considered favorable for derechos through four primary mechanisms: 1) Cold air aloft,  2) Ability to sustain strong storms along the leading edge of a gust front, 3) Organization potential for any ensuing convection, and 4) Sufficient flow within the ambient environment to favor development along downstream portion of the gust front. 

Figure 2. The Derecho Composite Parameter (DCP) for eastern North Carolina at 3 pm Sunday July 1, 2012

There were over 70 reports of severe weather across eastern North Carolina during the afternoon and evening of July 1. A Severe Thunderstorm Watch was issued by the Storm Prediction Center well before the storms reached the region. Numerous Severe Thunderstorms Warnings were issued by the Newport/Morehead City National Weather Service office with an average lead time of around 25 minutes. There was at least one possible gustnado that occurred in Beaufort County. Gustnadoes form due the interaction of the downdraft with the warm unstable air it is moving into. This interaction can lead to brief enhanced low level rotation that can cause considerable damage. Since these gustnadoes form on the gust front of the storm the damage they produce is considered straight line wind damage.

 






Synoptic Overview –

The environment over eastern North Carolina on the afternoon of July 1, 2012 was extremely unstable as an unusually strong heat wave had been underway for several days in advance of the event with widespread temperatures at or above 100 degrees over inland eastern North Carolina.  Lifted index values were well below -10 (Figure 3) with Precipitable Water values near 2 inches (Figure 4).

Figure 3. Lifted Index values below -10 over eastern North Carolina at 3 pm July 1, 2012

Figure 4. Precipitable Water Values of nearly 2 inches, 3 pm, July 1, 2012.

A weak heat-induced surface trough (Figure 5) was located along the North Carolina piedmont in advance of the developing line of thunderstorms (Figure 6) at mid-afternoon July 1.  As the line progressed east into the very unstable airmass, the line of thunderstorms strengthened and began to produce widespread wind damage (Figures 7,8,9).

Figure 5. SPC Surface Analysis showing weak heat-induced trough over the North Carolina Piedmont

  

Figure 6. SPC Radar Image at 3 pm July 1, 2012              Figure 7. SPC Radar Image at 4 pm July 1, 2012

 

Figure 8. SPC Radar Image at 5 pm July 1, 2012            Figure 9. SPC Radar Image at 6 pm July 1, 2012

This line of severe thunderstorms caused 1 death in Pitt County and 2 deaths in Beaufort County. The Warren Field Airport just outside Washington received extensive damage. Trees were downed and power outages were widespread throughout eastern North Carolina.

 

PRELIMINARY LOCAL STORM REPORT...SUMMARY

NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC

829 PM EDT SUN JUL 01 2012

 

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...

..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....

            ..REMARKS..

 

0910 AM     HAIL             5 SE ROPER              35.83N  76.55W

07/01/2012  E0.75 INCH       WASHINGTON         NC   BROADCAST MEDIA

 

0315 PM     HAIL             1 SE THURMAN            35.03N  76.99W

07/01/2012  M1.00 INCH       CRAVEN             NC   911 CALL CENTER

 

            RELAYED BY 911 CALL CENTER FROM CRAVEN COUNTY SHERIFFS

            DEPUTY

 

0315 PM     HAIL             2 S JAMES CITY          35.04N  77.02W

07/01/2012  E0.50 INCH       CRAVEN             NC   COCORAHS       

 

0320 PM     HAIL             2 SE JAMES CITY         35.05N  76.99W

07/01/2012  E1.00 INCH       CRAVEN             NC   PUBLIC         

 

0345 PM     MARINE TSTM WIND 2 NW PAMLICO SHORES     35.14N  76.01W

07/01/2012  M47 MPH          AMZ135             NC   WEATHER FLOW   

 

            MEASURED BY WEATHERFLOW STATION AT OCRACOKE

 

0359 PM     HAIL             CEDAR ISLAND            35.00N  76.33W

07/01/2012  E1.00 INCH       CARTERET           NC   PUBLIC         

 

            REPORTED BY CEDAR ISLAND FERRY TERMINAL

 

0405 PM     TSTM WND GST     FARMVILLE               35.59N  77.59W

07/01/2012  E65 MPH          PITT               NC   SPOTTER         

 

            SPOTTER ESTIMATED 60-65 MPH WINDS

 

0420 PM     TSTM WND DMG     WINTERVILLE             35.53N  77.40W

07/01/2012                   PITT               NC   AMATEUR RADIO  

 

            SEVERAL TREES DOWN

 

0423 PM     TSTM WND GST     GREENVILLE              35.60N  77.37W

07/01/2012  M74 MPH          PITT               NC   SPOTTER        

 

            TRAINED SPOTTER REPORTED 74 MPH WIND GUST ON HOME

            WEATHER STATION

 

0423 PM     TSTM WND DMG     GREENVILLE              35.60N  77.37W

07/01/2012                   PITT               NC   PUBLIC         

 

            10 X 20 BARN DESTROYED

 

0423 PM     HAIL             3 E CALYPSO             35.15N  78.05W

07/01/2012  E1.00 INCH       DUPLIN             NC   PUBLIC          

 

0425 PM     TSTM WND DMG     GREENVILLE              35.60N  77.37W

07/01/2012                   PITT               NC   PUBLIC         

 

            NUMEROUS TREES DOWN IN AN APARTMENT COMPLEX OFF 10TH

            STREET

 

0430 PM     TSTM WND GST     GREENVILLE              35.60N  77.37W

07/01/2012  M75 MPH          PITT               NC   LAW ENFORCEMENT

 

            MEASURED BY HIGHWAY PATROL ANEMOMETER

 

0430 PM     TSTM WND DMG     SIMPSON                 35.58N  77.28W

07/01/2012                   PITT               NC   PUBLIC         

 

            SEVERAL TREES DOWN THROUGHOUT SIMPSON

 

0430 PM     TSTM WND GST     GREENVILLE              35.60N  77.37W

07/01/2012  E65 MPH          PITT               NC   SPOTTER        

 

            WIND SPEED ESTIMATED. LARGE TREE DOWN ON 5TH ST IN

            FRONT OF ECU ART BUILDING

 

0433 PM     HAIL             FORT BARNWELL           35.27N  77.33W

07/01/2012  E1.00 INCH       CRAVEN             NC   PUBLIC         

 

0433 PM     TSTM WND DMG     2 S WILLIAMSTON         35.82N  77.06W

07/01/2012                   MARTIN             NC   PUBLIC         

 

            ROOF OFF BARN AND NUMEROUS TREES DOWN

 

0433 PM     TSTM WND DMG     1 NW CALICO             35.43N  77.26W

07/01/2012                   PITT               NC   EMERGENCY MNGR 

 

            *** 1 FATAL *** SHED FELL ON A MAN WHILE HE WAS TRYING

            TO PUT HIS GOLF CART IN STORAGE

 

0435 PM     HAIL             KINSTON                 35.28N  77.59W

07/01/2012  E1.00 INCH       LENOIR             NC   PUBLIC         

 

0437 PM     TSTM WND DMG     WASHINGTON              35.56N  77.05W

07/01/2012                   BEAUFORT           NC   PUBLIC         

 

            NUMEROUS TREES DOWN

 

0440 PM     TSTM WND DMG     WARSAW                  35.00N  78.09W

07/01/2012                   DUPLIN             NC   911 CALL CENTER

 

            911 CALL CENTER REPORTS NUMEROUS POWER LINES DOWN

 

0440 PM     TSTM WND DMG     GILEAD                  35.45N  76.99W

07/01/2012                   BEAUFORT           NC   EMERGENCY MNGR 

 

            *** 2 FATAL *** TREE FELL ON A COUPLE IN A GOLF CART

 

0445 PM     TSTM WND DMG     WASHINGTON              35.56N  77.05W

07/01/2012                   BEAUFORT           NC   EMERGENCY MNGR 

 

            *** 40 INJ *** OVER 40 TREATED THROUGHOUT THE COUNTY

            FOR STORM RELATED INJURIES

 

0453 PM     TSTM WND DMG     3 NW WENONA             35.76N  76.67W

07/01/2012                   WASHINGTON         NC   911 CALL CENTER

 

            TREES DOWN NEAR HIGHWAY 99 NORTHWEST OF WENONA.

 

0507 PM     TSTM WND GST     NEW BERN                35.12N  77.08W

07/01/2012  M65 MPH          CRAVEN             NC   ASOS           

 

0510 PM     MARINE TSTM WIND 2 W EAST LAKE LANDING   35.90N  76.01W

07/01/2012  M54 MPH          AMZ130             NC   PUBLIC         

 

            REPORTED BY ALLIGATOR RIVER BRIDGE TENDER

 

0515 PM     TSTM WND DMG     2 NW KILKENNY           35.67N  76.26W

07/01/2012                   TYRRELL            NC   911 CALL CENTER

 

            TRRES DOWN ALONG HIGHWAY 94 NORTHWEST OF KILKENNY.

 

0515 PM     TSTM WND DMG     NEW BERN                35.12N  77.08W

07/01/2012                   CRAVEN             NC   PUBLIC         

 

            SEVERAL TREES DOWN IN THE AREA

 

0518 PM     TSTM WND GST     CHERRY POINT            34.92N  76.88W

07/01/2012  M84 MPH          CRAVEN             NC   ASOS           

 

0530 PM     TSTM WND GST     NEW RIVER               34.76N  77.41W

07/01/2012  M62 MPH          ONSLOW             NC   ASOS           

 

0530 PM     TSTM WND DMG     5 NW HAVELOCK           34.94N  76.99W

07/01/2012                   CRAVEN             NC   PUBLIC         

 

            NUMEROUS TREES DOWN ALONG HWY 70 IN BETWEEN HAVELOCK

            AND NEW BERN

 

0545 PM     MARINE TSTM WIND 1 W WAVES LANDING       35.57N  75.49W

07/01/2012  M68 MPH          AMZ135             NC   WEATHER FLOW   

 

0545 PM     TSTM WND GST     OCRACOKE                35.10N  75.98W

07/01/2012  M67 MPH          HYDE               NC   WEATHER FLOW   

 

            MEASURED BY WEATHERFLOW STATION AT OCRACOKE

 

0547 PM     TSTM WND DMG     EMERALD ISLE            34.67N  77.03W

07/01/2012                   CARTERET           NC   PUBLIC         

 

            SEVERAL TREES DOWN ALONG EMERALD ISLE

 

0547 PM     TSTM WND DMG     CEDAR POINT             34.68N  77.08W

07/01/2012                   CARTERET           NC   SPOTTER        

 

            SPOTTER REPORTED A LARGE 20 X 20 TENT BLOWN OVER IN

            FRONT OF LOCAL FURNITURE STORE

 

0550 PM     TSTM WND DMG     NEWPORT                 34.79N  76.86W

07/01/2012                   CARTERET           NC   NWS EMPLOYEE   

 

            TREES DOWN JUST WEST OF NWS OFFICE

 

0555 PM     MARINE TSTM WIND FRISCO                  35.23N  75.61W

07/01/2012  M56 MPH          DARE               NC   WEATHER FLOW   

 

            WEATHERFLOW STATION AT FRISCO WOODS

 

0556 PM     TSTM WND GST     BEAUFORT                34.72N  76.65W

07/01/2012  M61 MPH          CARTERET           NC   PUBLIC         

 

            MEASURED ON HOME WEATHER STATION

 

0600 PM     TSTM WND DMG     NEWPORT                 34.79N  76.86W

07/01/2012                   CARTERET           NC   AMATEUR RADIO  

 

            TREES DOWN ON POWERLINES NEAR NEWPORT FIRE STATION 43.

            REPORTED BY SKYWARN

 

 

&&

 

EVENT NUMBER MHX1200192 MHX1200193 MHX1200194 MHX1200195 MHX1200196

MHX1200198 MHX1200197 MHX1200222 MHX1200199 MHX1200205 MHX1200219

MHX1200200 MHX1200212 MHX1200221 MHX1200229 MHX1200202 MHX1200215

MHX1200225 MHX1200201 MHX1200204 MHX1200203 MHX1200216 MHX1200217

MHX1200214 MHX1200206 MHX1200226 MHX1200213 MHX1200224 MHX1200207

MHX1200208 MHX1200223 MHX1200210 MHX1200211 MHX1200220 MHX1200227

MHX1200209 MHX1200230 MHX1200228 MHX1200218 

 

$$

 

Damage Pictures from Beaufort and Pitt Counties
Photos courtesy of: NWS Newport/Morehead City Damage Assessment Team 

Damage at Warren Field Airport in Washington, NC followed July 1, 2012 Derecho

Airplane flipped over near Washington, NC Airport

Case Study Team:
Bob Frederick

Chris Collins