A band of strong to severe storms developed along a lee side trough and in advance of an amplifying long wave trough moving east over the Great Lakes. The line of storms produced scattered wind damage with one report of hail the size of quarters.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS RAH wrote it up.
A band of strong to severe storms developed along a lee side trough and in advance of an amplifying long wave trough moving east over the Great Lakes. The line of storms produced scattered wind damage with one report of hail the size of quarters.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Raleigh, NC wrote its last area forecast discussion before the first event at Jul 27, 12:15 PM EST, 44 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 115 PM EDT FRI JUL 27 2012 .SYNOPSIS... HOT CONDITIONS WILL CONTINUE OUT AHEAD OF A COLD FRONT ACROSS OUR REGION TODAY. THE COLD FRONT WILL APPROACH FROM THE NORTH... PUSHING INTO CENTRAL AND EASTERN NORTH CAROLINA SATURDAY NIGHT. && .NEAR TERM /THROUGH SATURDAY NIGHT/... AS OF 1045 AM... A LOW PRESSURE SYSTEM CONTINUES TO ROTATE OUT OF VIRGINIA THIS MORNING AND OFF TO THE NORTHEAST. AN ASSOCIATED SURFACE TROUGH CURRENTLY OVER THE MOUNTAINS WILL SHIFT EASTWARD AND BE THE FOCUS FOR ANY CONVECTION THIS AFTERNOON. MOST OF THE ATTENTION SHOULD BE IN THE NORTHWEST TODAY WITH MORE ISOLATED CONVECTION IN THE SOUTHEAST POSSIBLY FIRING OFF OF ANY ADVANCING SEA BREEZE THIS AFTERNOON. MOST OF THE ACTIVITY SHOULD HOLD OFF UNTIL AFTER 18Z. PREVIOUS DISCUSSION FOLLOWS. -ELLIS HEAT ADVISORY CONTINUES AS POSTED FOR TODAY BUT IS IN DANGER FROM SEVERAL DIRECTIONS. SOME CIRRUS DROPPING SOUTH ACROSS THE VIRGINIA BORDER AT THIS TIME AND IF THICK ENOUGH CAN EASILY KNOCK A FEW DEGREES OFF FULL SUN HIGH TEMPERATURES. THE RISK OF CONVECTION IS HIGHER THAN THURSDAY... WITH A WEAK 850 MILLIBAR TROUGH OVER THE MOUNTAINS... AND CONVECTIVE TRIGGER TEMPERATURES IN THE 92 TO 95 RANGE. THE AIR MASS IS MOST UNSTABLE OVER THE SOUTHEAST... BUT LOW LEVEL SPEED DIVERGENCE MAY DAMPEN INITIATION OF CONVECTION THERE. HOWEVER THE AIR MASS WOULD BE RIPE TO SUSTAIN CONVECTION ADVECTING INTO THE AREA OR INITIATED FROM BOUNDARIES GENERATED BY CONVECTION OUTSIDE THE SOUTHEAST. MODEL 1000 TO 850 MILLIBAR THICKNESS FORECASTS VERIFIED TOO HIGH FOR THURSDAY... AND MODEL FORECASTS ARE FOR NO MORE THAN ACTUALLY OCCURRED ON THURSDAY. PERSISTENCE OR A TOUCH LOWER FORECAST FOR HIGH TEMPERATURES TODAY... 94 TO 99 DEGREES. WEAK LOW LEVEL CONVERGENCE IN A MODERATELY UNSTABLE AIR MASS WITH CAPE NEAR 1000 JOULES WILL FAVOR THE NORTHWEST PIEDMONT AS THE INITIAL AREA FOR CONVECTION TODAY... AROUND 1 TO 3 PM. MOST MODELS SHIFT THIS WEAK CONVERGENCE EAST TO AT LEAST HIGHWAY ONE BY SUNSET. SOME CONVECTIVE ALLOWING MODELS AND THE NAM SUGGEST SOUTH CAROLINA CONVECTION POTENTIALLY ADVECTING NORTHEAST LATE IN THE DAY... WHICH IS MORE THAN REASONABLE. BY THE TIME ALL IS SAID AND DONE... ABOUT A 40 PERCENT RAIN CHANCE AREA WIDE TODAY... WITH DIFFERENCES IN TIMING. THE AIR MASS OVER THE SOUTHEAST IS THE MOST FAVORABLE FOR CONVECTION TODAY... BUT MAY BE LATEST TO SEE CONVECTION... LESSENING THE IMPACT. WHILE NOT AS UNSTABLE ELSEWHERE...THE AIR MASS WILL CERTAINLY SUPPORT CONVECTION. A STORM OR TWO COULD BECOME SEVERE... WITH THE PRIMARY THREAT BEING DOWNBURST WINDS. WITH A BROAD UPPER TROUGH OVER THE AREA... AND A SURFACE TROUGH BISECTING CENTRAL NORTH CAROLINA... NORTHEAST TO SOUTHWEST... EXPECT AT LEAST SOME CONVECTION TO PERSIST UNTIL ALMOST DAWN... MAINLY NEAR AND EAST OF HIGHWAY ONE. LOW TEMPERATURES IN THE MID 70S. A REINFORCING SHORT WAVE WILL DROP INTO THE MEAN TROUGH POSITION OVER THE EAST COAST SATURDAY AFTERNOON. THE TIMING OF THIS WAVE AND THE POSITION OF THE SURFACE TROUGH WILL FAVOR THE SOUTHEAST HALF OF CENTRAL NORTH CAROLINA FOR CONVECTION SATURDAY. SLIGHT RAIN CHANCES NORTHWEST TO NEAR 50 PERCENT SOUTHEAST. WINDS ALOFT SLIGHTLY WEAKER... AND SURFACE TEMPERATURES A TOUCH LOWER THAN FRIDAY. THE AIR MASS ALOFT WILL ALSO BE DRYING OUT WITH TIME DURING THE DAY. SEVERE WEATHER THREAT IS FURTHER REDUCED FROM FRIDAY... AND MAINLY SOUTHEAST... BUT NOT ZERO. THUNDERSTORMS DOWNBURST WINDS WILL CONTINUE TO BE THE POSSIBLE THREAT. AFTERNOON HIGH TEMPERATURES IN THE LOW TO MID 90S. CONSENSUS IS THE NAM IS A SLOW OUTLIER WITH ITS MORE WEST UPPER LEVEL TROUGH. EXPECT CONVECTION TO HAVE ADVECTED EAST OUT OF CENTRAL NORTH CAROLINA BY MIDNIGHT SATURDAY NIGHT... WITH THE POSSIBLE EXCEPTION OF THE SOUTHEAST. SLIGHTLY COOLER AIR ADVECTING INTO THE AREA BEHIND THE TROUGH. LOW TEMPERATURES NEAR 70 NEAR VIRGINIA AND NORTHWEST... LOW TO MID 70S ELSEWHERE. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 255 AM FRIDAY... SUNDAY:THE SIGNIFICANT SHORT WAVE TROUGH THAT WILL AMPLIFY ACROSS THE MIDDLE ATLANTIC STATES DURING THE LATTER NEAR TERM (DAY TWO) IS EXPECTED TO MOVE OFFSHORE AND LEAVE CENTRAL NORTH CAROLINA IN GENERALLY SUBSIDENT TO NEUTRAL DEEP LAYER VERTICAL MOTION ON SUNDAY. HOWEVER...THE LOW LEVEL FRONTAL ZONE FROM THE LOWER GREAT LAKES TO THE CENTRAL PLAINS THIS MORNING WILL BE VERY SLOW TO MOVE SOUTHEASTWARD AND WILL LIKELY STALL -- WITH ONE FRONTAL SEGMENT ORIENTED FROM SOUTHWEST TO NORTHEAST IN THE IMMEDIATE LEE OF THE SOUTHERN APPALACHIANS TO A WEAK WAVE OVER THE SOUTH CAROLINA UPSTATE... AND A MORE EAST WEST BACK DOOR FRONTAL ORIENTATION ACROSS CENTRAL AND EASTERN NORTH CAROLINA -- BY DAYBREAK. LOW LEVEL CONVERGENCE INVOF THIS DIFFUSING (OWING TO BEING LEFT BEHIND BY THE PARENT SHORT WAVE TROUGH) FRONTAL ZONE AND THE SEA BREEZE...AMIDST RESIDUALLY RICH BOUNDARY LAYER MOISTURE AT OR ABOVE 70 DEGREES...MAY SUPPORT ISOLATED TO WIDELY SCATTERED AFTERNOON STORMS OVER SOUTHERN AND EASTERN NORTH CAROLINA. SOME OF THIS CONVECTION WILL LIKELY PROPAGATE FROM THE SANDHILLS AND SOUTHERN-CENTRAL COASTAL PLAIN NORTHWARD INTO PORTIONS OF THE PIEDMONT BEFORE DISSIPATING WITH NOCTURNAL COOLING DURING THE EVENING. HIGHS IN THE LOWER TO MIDDLE 90S. SUNDAY NIGHT: SOME OF THIS CONVECTION MAY CONTINUE TO PULSE ALONG OUTFLOW AND IN RESPONSE TO THE LATE NIGHT ARRIVAL OF DEEPER LAYER FORCING COURTESY OF THE NEXT SHORT WAVE TROUGH ALOFT...PARTICULARLY OVER PORTIONS OF THE WESTERN AND SOUTHERN PIEDMONT. LOWS GENERALLY 70 TO 75. MONDAY AND MONDAY NIGHT: NWP GUIDANCE INDICATES THE APPROACH OF THE AFOREMENTIONED SHORT WAVE TROUGH ALOFT WILL HELP FURTHER ORGANIZE AND DEEPEN THE LOW INITIALLY OVER THE SOUTH CAROLINA UPSTATE...WHICH MAY THEN DRIFT SLOWLY NORTHEASTWARD TOWARD CENTRAL NORTH CAROLINA EARLY MONDAY. THIS FEATURE WILL FOCUS LOW LEVEL CONVERGENCE AND ISENTROPIC UPGLIDE IN SOUTH TO SOUTHEAST 850 MILLIBAR FLOW ATOP THE DIFFUSING FRONTAL ZONE/REMNANT OUTFLOW...AND LEAD TO SCATTERED TO NUMEROUS STORMS AS THE BOUNDARY LAYER DESTABILIZES AND WARMS INTO THE MIDDLE 80S TO AROUND 90 DEGREES. HAVE ACCORDINGLY RAISED POPS INTO THE 40 TO 50 PERCENT CHANCE RANGE. THIS CONVECTION WILL LIKELY NOCTURNALLY WANE FROM WEST TO EAST AS THE PARENT WAVE ALOFT DRIFTS TOWARD THE COAST OVERNIGHT. A LACK OF ANY SIGNIFICANT WIND THROUGH THE COLUMN SUGGESTS THE STORMS THROUGHOUT THE PERIOD WILL BE DISORGANIZED/PULSE IN NATURE...CAPABLE OF PRODUCING PRECIPITATION LOADED DOWNBURST WINDS. && .LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 310 AM FRIDAY... A LONG WAVE TROUGH ALOFT WILL PERSIST OVER THE EAST COAST THROUGHOUT THE WEEK. NUMEROUS SHORT WAVELENGTH EMBEDDED SHORT WAVE TROUGHS OR IMPULSES... AND A PERSISTENT LOW LEVEL TROUGH/CONVERGENCE AXIS BENEATH THE CYCLONIC FLOW ALOFT...WILL FAVOR ABOVE AVERAGE AND DIURNALLY MAXIMIZED CHANCES OF WEAKLY SHEARED PULSE CONVECTION IN THE 30 TO 40 PERCENT RANGE...AMIDST A VERY MOIST ENVIRONMENT CHARACTERIZED BY PRECIPITABLE WATER VALUES AROUND TWO INCHES... THROUGHOUT THE PERIOD. LOWER HEIGHTS WITHIN THE TROUGH ALOFT... AND AFOREMENTIONED CONVECTION AND ASSOCIATED CLOUD COVER...SHOULD HOLD TEMPERATURES CLOSER TO AVERAGE - WITHIN A FEW DEGREES OF 90 FOR HIGHS...AND GENERALLY IN THE LOWER TO MIDDLE 70S FOR LOWS. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AS OF 115 PM... 24 HOUR TAF PERIOD: CURRENTLY VFR CONDITIONS ARE PREVAILING AT ALL LOCATIONS. AS A LOW MOVES OUT OF VIRGINIA TO THE NORTHEAST...AN ASSOCIATED TROUGH OR WEAK FRONTAL BOUNDARY WILL BE DRAGGED ACROSS THE AREA THIS AFTERNOON/EVENING. THE BEST CHANCE FOR CONVECTION WILL BE IN THE TRIAD AT KINT AND KGSO. WITH A CUMULUS FIELD ALREADY DEVELOPING...THE FOCUS FOR STORMS WILL FIRST BE IN THE NORTHWEST WITH CONVECTION DEVELOPING IN THE FOOTHILLS OR ROLLING OFF THE MOUNTAINS LATER THIS AFTERNOON. WHILE A SEVERE WEATHER OUTBREAK IS NOT ANTICIPATED...A FEW OF THESE CELLS COULD BECOME SEVERE WITH DAMAGING WINDS BEING THE PRIMARY THREAT. HAVE INCLUDED STORMS AS A TEMPO GROUP IN THE TRIAD FROM 21Z FRIDAY THROUGH 00Z SATURDAY. AS THE EVENING PROGRESSES...THE CHANCE FOR SHOWERS AND THUNDERSTORMS WILL MOVE TO THE EAST AFFECTING KRDU SOMETIME BETWEEN 22Z FRIDAY AND 02Z SATURDAY. THE THREAT WILL CONTINUE IN THE EAST LATER ON BUT HAVE LEFT MENTION OF THUNDER OUT FOR THE EASTERN SITES AT THIS TIME AS IT WILL NOT MOVE INTO THE AREA UNTIL AFTER THE CRITICAL TAF PERIOD. MORE DETAILS FOR THE EAST WILL FOLLOW WITH THE NEXT ISSUANCE AT 00Z AND WILL AMEND AS NEEDED IN THE SHORT TERM. WINDS SHOULD REMAIN FAIRLY LIGHT BUT WILL BE SWITCHING TO NORTHWESTERLY AFTER THE PASSAGE OF THE TROUGH. EASTERN SITES MAY NOT REALIZE THIS WIND SHIFT HOWEVER AND COULD STAY SOUTHWESTERLY THROUGH THE TAF PERIOD. REGARDLESS...WINDS WILL BE LIGHT 5-10 KNOTS. THE ONLY VISIBILITY RESTRICTIONS THROUGH THE TAF PERIOD SHOULD BE WITHIN THUNDERSTORMS...OTHERWISE NO FOG OR LOW STRATUS IS EXPECTED. LONG TERM: DIURNAL SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE THROUGH THE BULK OF NEXT WEEK WITH MONDAY AFTERNOON BEING THE LARGEST THREAT FOR SHOWERS AND THUNDERSTORMS AS A LOW DEVELOPS OVER CENTRAL NORTH CAROLINA. THIS MAY YIELD PERIODS OF ADVERSE AVIATION CONDITIONS. && .RAH WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS EVENING FOR NCZ010-011-026>028-041>043-073>078-083>086-088-089. && NEAR TERM...ELLIS/ SHORT TERM...MWS LONG TERM...MWS AVIATION...ELLIS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RALEIGH NC 436 AM EDT FRI JUL 27 2012 NCZ010-011-026>028-041>043-073>078-083>086-088-089-280845- WARREN-HALIFAX-FRANKLIN-NASH-EDGECOMBE-WAKE-JOHNSTON-WILSON-STANLY- MONTGOMERY-MOORE-LEE-HARNETT-WAYNE-ANSON-RICHMOND-SCOTLAND-HOKE- CUMBERLAND-SAMPSON- 436 AM EDT FRI JUL 27 2012 ...HEAT ADVISORY IN EFFECT FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA. .DAY ONE...TODAY AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. HEAT ADVISORY. THERE IS A SLIGHT RISK OF SEVERE STORMS THIS AFTERNOON AND EVENING. THE MAIN THREAT WILL BE FROM DAMAGING WIND GUSTS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. STRONG TO SEVERE STORMS WILL BE POSSIBLE AGAIN ON SATURDAY OVER PORTIONS OF THE EASTERN PIEDMONT AND COASTAL PLAIN...WITH A MAIN THREAT OF DAMAGING WIND GUSTS. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTERS SHOULD STAY ALERT AND REPORT ANY SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE. NCZ007>009-021>025-038>040-280845- PERSON-GRANVILLE-VANCE-FORSYTH-GUILFORD-ALAMANCE-ORANGE-DURHAM- DAVIDSON-RANDOLPH-CHATHAM- 436 AM EDT FRI JUL 27 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA. .DAY ONE...TODAY AND TONIGHT. THERE IS A SLIGHT RISK OF SEVERE STORMS ON THIS AFTERNOON AND EVENING. THE MAIN THREAT WILL BE FROM DAMAGING WIND GUSTS. TEMPERATURES IN THE MID AND UPPER 90S...WITH HEAT INDEX VALUES BETWEEN 100 AND 105 DEGREES...ARE EXPECTED TODAY. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTERS SHOULD STAY ALERT AND REPORT ANY SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RALEIGH NC 143 PM EDT FRI JUL 27 2012 NCZ022-023-039-040-271845- ALAMANCE-CHATHAM-GUILFORD-RANDOLPH- 143 PM EDT FRI JUL 27 2012 ...A STRONG THUNDERSTORM WILL MOVE ACROSS RANDOLPH...GUILFORD... CHATHAM AND ALAMANCE COUNTIES THROUGH 245 PM EDT... AT 143 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER RANDLEMAN...MOVING NORTHEAST AT 35 MPH. SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...CLIMAX...FOREST OAKS. HAZARDS INCLUDE... HALF INCH DIAMETER SIZE HAIL. GUSTY WINDS OF 40 MPH. DEADLY CLOUD TO GROUND LIGHTNING. SEEK SHELTER IN A NEARBY BUILDING OR VEHICLE. STRONG WINDS ARE CAPABLE OF KNOCKING DOWN SMALL TREES AND BLOWING AROUND TRASH CANS... POTTED PLANTS...LAWN FURNITURE AND OTHER LIGHT OUTDOOR OBJECTS. && LAT...LON 3611 7967 3588 7932 3564 7977 3576 7996 TIME...MOT...LOC 1743Z 219DEG 31KT 3579 7979 NP
The Raleigh/Durham radar (KRAX), 105 km away, was scanning. The volume nearest the first event began at 18:00 UTC.
10 thunderstorm wind, 2 hail. Local standard time, as filed.
A tree was blown down onto a house. The monetary damage was unknown.
Quarter to nickel size hail was reported in Rosemary.
Trees and power lines were blown down near Pfafftown.
Numerous trees and power lines were blown down in and around the Pfafftown area. One tree, which was approximately 250 years old, fell on a house in Pfafftown. Monetary damage was unknown. Due all the downed trees and power lines, 5,000 power outages were reported.
A tree and several large limbs were blown down along a swath from near Roxboro to near Surl.
Numerous trees and power lines were blown down along a swath from near Elon College to Mebane. Mebane was especially hard hit, with damage to 15 structures and 9 vehicles.
Several trees were blown down near Schley near the intersection of Breeze Road and Guess Road.
Numerous trees were blown down in Siler City.
Several trees were blown down in the Louisburg area.
A couple of trees were blown down along a swath from near Oakboro to near Badin, with one tree falling on a home near Badin. Monetary damages were unknown.
Several trees were blown down just west of Siler City near the Randolph County line.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in North Carolina in 2012Every state in 2012This day in weather historyWarnings in North Carolina, July 2012
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 398117, 398118, 398119, 398127, 398129, 398137, 398141, 398142, 398144, 398146, 398147, 398148.