Flash Flood Warning 85, NWS Raleigh, NC

000 
WGUS72 KRAH 101245
FFSRAH

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
845 AM EDT WED SEP 10 2008

NCC007-153-101445-
/O.CON.KRAH.FF.W.0085.000000T0000Z-080910T1445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ANSON NC-RICHMOND NC-
845 AM EDT WED SEP 10 2008

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 AM EDT FOR
RICHMOND AND EASTERN ANSON COUNTIES...

AT 840 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A THUNDERSTORM PRODUCING  OVER THE WARNED AREA.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO ROCKINGHAM 
AND CORDOVA.

RADAR AND GROUND REPORTS INDICATE RAINFALL IN EXCESS OF SIX INCHES 
NEAR AND SOUTHWEST OF ROCKINGHAM. A LARGER AREA OF FOUR TO SIX INCH 
RAINS OVER THREE HOURS EXTENDS WEST INTO ANSON COUNTY ALONG HIGHWAY 
74 AND OVER A LARGE PORTION OF SOUTHWEST RICHMOND COUNTY. HEAVY 
RAINS ARE EXPECTED TO CONTINUE AT LEAST THROUGH 930 AM AND PERHAPS 
BEYOND. 

AT 840 AM...RAINFALL RATE OF ONE TO TWO INCHES PER HOUR WERE STILL 
OCCURRING IN SOUTHEAST ANSON COUNTY SOUTH OF HIGHWAY 74...WITH ONE 
INCH PER HOUR RATES OR MORE OVER MUCH OF SOUTHWEST RICHMOND COUNTY.

THIS IS A DANGEROUS SITUATION. THERE ARE MULTIPLE RURAL ROAD 
CLOSURES AND WATER HAS ENTERED SOME HOMES. AVOID TRAVEL IN THE 
WARNED AREA THIS MORNING TO ALLOW EMERGENCY PERSONNEL TO DO THEIR 
JOBS. 

EXCESSIVE RUNOFF FROM HEAVY RAINFALL IS CAUSING FLOODING OF 
SMALL CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. 
ADDITIONALLY...COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF 
CREEKS...STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO FLOODING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

LAT...LON 3482 7994 3509 7998 3517 7985 3517 7967
      3515 7964 3516 7960 3507 7957 3506 7950
      3504 7946 3499 7957 3497 7958 3490 7957
      3485 7966 3482 7979 3481 7992

$$

14

000 
WGUS72 KRAH 101349
FFSRAH

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
949 AM EDT WED SEP 10 2008

NCC007-153-101445-
/O.CON.KRAH.FF.W.0085.000000T0000Z-080910T1445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ANSON NC-RICHMOND NC-
949 AM EDT WED SEP 10 2008

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 AM EDT FOR
RICHMOND AND EASTERN ANSON COUNTIES...

AT 940 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A THUNDERSTORM PRODUCING  OVER THE WARNED AREA.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO ROCKINGHAM 
AND CORDOVA

AT 940 AM NATIONAL WEATHER SERVICE RADAR INDICATED HEAVY RAINS 
ADVANCING NORTH FROM SOUTH CAROLINA TOWARD ANSON COUNTY AND 
ROCKINGHAM. THESE SHOWERS WILL COLLIDE WITH THE SLOWER MOVING CELLS 
OVER ANSON AND RICHMOND COUNTY THIS MORNING. RAINFALL RATES MAY 
EXCEED TWO INCHES PER HOUR FOR A TIME THIS MORNING SOUTH OF HIGHWAY 
74. TO THE NORTH OF 74...HEAVY RAINS WILL BE MORE ISOLATED...WITH 
MOST LOCATIONS RECEIVING ADDITIONAL RAINFALL OF TWO THIRDS INCH OR 
LESS. 

EXCESSIVE RUNOFF FROM HEAVY RAINFALL IS CAUSING FLOODING OF SMALL 
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES IN THE WARNED AREA. 
ADDITIONALLY...COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF 
CREEKS...STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO FLOODING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

LAT...LON 3482 7994 3509 7998 3517 7985 3517 7967
      3515 7964 3516 7960 3507 7957 3506 7950
      3504 7946 3499 7957 3497 7958 3490 7957
      3485 7966 3482 7979 3481 7992

$$

14

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
400 AM EDT WED SEP 10 2008

.SYNOPSIS...A BACKDOOR COLD FRONT WILL DROP SOUTHWARD THROUGH THE
AREA TODAY... REACHING SOUTHERN NORTH CAROLINA BY THIS EVENING. A
COOL AND DAMP HIGH PRESSURE AREA WILL PUSH IN FROM THE NORTH TONIGHT
THROUGH THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 220 AM WEDNESDAY...

IT STILL APPEARS THAT A BRIEF COLD AIR DAMMING EVENT IS IMMINENT...
BUT ITS SETUP WILL LIKELY BE DELAYED ACCORDING TO RECENT
OBSERVATIONAL AND MODEL TRENDS. THE LATEST SURFACE ANALYSIS SHOWS
THE BACKDOOR FRONT STILL ACROSS NRN VA BACK THROUGH SW VA. WITH THE
SURFACE HIGHS CENTER STILL BACK OVER MI... THE SOUTHWARD PUSH OF
THE COOLER AND MORE DENSE AIR EAST OF THE MOUNTAINS HAS NOT YET
BEGUN. ONCE THE SURFACE HIGH MOVES TO LAKE ERIE BY AFTERNOON... THE
SURGE OF MORE STABLE AIR SHOULD BEGIN IN EARNEST. THE AIR MASS
REMAINS UNSTABLE ACROSS NC WITH LIFTED INDICES HOLDING AT -2 TO
-4... AND HEAVY SHOWERS AND ISOLATED STORMS CONTINUE TO DEVELOP OVER
THE NORTHERN CWA... WITH LIFT LIKELY BOLSTERED BY THE PASSAGE OF THE
RIGHT ENTRANCE REGION OF AN 80-90 KT UPPER JET. OBSERVED
PRECIPITABLE WATER FROM CIRA SHOWS A STEADY STREAM OF GREATER THAN
150% OF NORMAL INTO NC FROM THE WSW... AND WATER VAPOR IMAGERY
CONFIRMS THIS RIVER OF HIGH ATMOSPHERIC MOISTURE... SO THE
AVAILABILITY OF MOISTURE THROUGH TODAY SHOULD NOT BE AN ISSUE. THE
WIND FIELD THROUGH AT LEAST THE LOWEST 3 KM IS QUITE WEAK... SO THE
CONTRIBUTION TO LIFT BY ISENTROPIC UPGLIDE IS LIKELY TO BE SMALL.
BUT WITH THE UPPER JET STREAK HOLDING TO OUR NNE KEEPING FAVORABLE
DYNAMIC LIFT POTENTIAL OVER NC AS WEAK/ SHEARING/ DIFFICULT-TO-TRACK
MID LEVEL PERTURBATIONS PASS THROUGH... THIS FORCING SHOULD BE
ENOUGH TO KEEP HIGH LIKELY TO CATEGORICAL POPS OVER THE CWA THROUGH
TODAY. GIVEN THE ANTECEDENT WET GROUND AND RECENT RAINS... WILL NEED
TO WATCH ANY HEAVY AND/OR TRAINING RAIN BANDS VERY CLOSELY... AND
THIS RISK OF ISOLATED URBAN FLOODING WILL BE MENTIONED IN THE
HAZARDOUS WEATHER OUTLOOK. MODEL GUIDANCE IS IN GOOD AGREEMENT
BRINGING THE FRONT DOWN TO THE NC/VA BORDER REGION BY MID MORNING...
BUT DURING THE AFTERNOON THE GFS PUSHES IT DOWN TO OUR SOUTHERN
COUNTIES WHEREAS THE NAM HOLDS IT ACROSS THE CENTRAL SECTIONS.
LOOKING BACK AT LOCAL DAMMING RESEARCH INCLUDING COMPOSITE MAPS OF
PAST CASES... GIVEN THE MARGINAL STRENGTH OF THIS SURFACE HIGH (LESS
THAN 1030 MB THROUGH TODAY) AND OF THE 850 MB FLOW... THE HIGHS
CENTER NEEDS TO PUSH OVER NEW YORK STATE IN ORDER TO INITIATE
DAMMING IN NC. SINCE THIS IS NOT EXPECTED TO HAPPEN UNTIL THIS
EVENING... HAVE GONE WITH A DELAY IN THE DAMMING SETUP. PRIMARILY
THIS WILL MEAN LINGERING INSTABILITY THROUGH THIS AFTERNOON OVER THE
SOUTHERN HALF OF THE CWA AT LEAST... AND WE WILL ALSO NEED TO RAISE
HIGHS ROUGHLY A CATEGORY... TO AROUND 74-84 ORIENTED NORTH TO SOUTH.
THIS IS STILL A MARGINAL RISE IN TEMPS FOR AREAS NORTH OF HIGHWAY
64.

AS THE HIGH CENTER SHIFTS EASTWARD INTO NEW ENGLAND AND STRENGTHENS
A BIT TO AROUND 1030 MB UNDER THE INFLUENCE OF CONFLUENT FLOW
ALOFT... THE FRONT SHOULD SLOWLY PUSH INTO THE SOUTHERN CWA TONIGHT.
MORE STABLE AIR SHOULD PUSH IN FROM THE NORTH AND WITH THE UPPER
JETLET SHIFTING NE AND AWAY FROM NC WHILE ISENTROPIC UPGLIDE WEAKENS
FURTHER... WILL SHOW A DECREASING TREND OF POPS TO CHANCE NORTH AND
LOW LIKELY POPS SOUTH FOR LIGHT RAIN OR DRIZZLE. LOWS 63-70. -GIH

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 315 AM WEDNESDAY...

THURSDAY/THURSDAY NIGHT: CONFIDENCE IN THE FORECAST DETAILS HERE IS
BELOW NORMAL. WITH THE DEPARTURE OF THE MEAN MID LEVEL TROUGH OFF
THE NOVA SCOTIA COAST... THE FLOW ALOFT OVER EASTERN CANADA AND THE
NORTHEAST STATES FLATTENS... AND SLOW BUT STEADY MID LEVEL HEIGHT
RISES COMMENCE OVER NC. THE DAMMING SURFACE HIGH SHOULD MAX OUT IN
STRENGTH NEAR 1030 MB LATE TONIGHT BEFORE SHIFTING OFF THE COAST AND
WEAKENING LATE THURSDAY/THURSDAY NIGHT IN THE FACE OF THE QUICKLY
WANING UPPER SUPPORT. BUT AS IS OFTEN THE CASE WITH THESE DAMMING
EVENTS...THE COOL STABLE SURFACE-BASED POOL WILL BE DIFFICULT TO
DISLODGE IMMEDIATELY. WITH MOISTURE REMAINING HIGH THROUGH THE
COLUMN WITH ABUNDANT CLOUD COVER TO LIMIT INSOLATION...EXPECT THE
WEDGE REGIME TO HOLD FIRM OVER MOST OF THE PIEDMONT THROUGH THURSDAY
NIGHT. WITH THE GFS SHOWING WEAK ISENTROPIC UPGLIDE PERSISTING AND
WILL POSSIBLE ADDITIONAL LIFT SUPPORT FROM THE LEFT EXIT REGION OF
AN UPPER JET NOSING IN FROM THE NE... HAVE HELD ONTO LOW CHANCE
POPS...A BIT HIGHER SOUTH WHERE MODELS DEPICT WEAK DESTABILIZATION.
HAVE HIGHS THURSDAY OF 72-80... FOLLOWED BY LOWS OF 64-70.

FOR FRIDAY/FRIDAY NIGHT: ANALYSIS OF SIMILAR DAMMING CASES WITH THIS
SURFACE HIGH STRENGTH AND MOVEMENT AND MID LEVEL PATTERN SUGGESTS
EROSION WILL LIKELY OCCUR EARLY FRIDAY... WHEN THERE SHOULD BE
ENOUGH VERTICAL MIXING AND HORIZONTAL COOL POOL DRAINAGE TO FINALLY
DISSIPATE THE RESIDUAL WEDGE AIR MASS. BUT MOISTURE IS EXPECTED TO
REMAIN HIGH WITH THE GFS AND NAM SHOWING PRECIPITABLE WATER STILL
WELL ABOVE 2 INCHES. WILL GO WITH 40-50% CHANCES WITH CONTINUED HIGH
CLOUD COVER. WITH STEADILY RISING LOW LEVEL THICKNESSES...
TEMPERATURES SHOULD START TO APPROACH NORMALS ONCE AGAIN... AND HAVE
GONE WITH HIGHS OF 80-86. WEAK SURFACE TROUGHING IS EXPECTED THROUGH
CENTRAL NC FRIDAY NIGHT BUT WITH RISING HEIGHTS AND NO FORCING
EVIDENT... WILL TREND BOTH POPS AND SKY COVER DOWNWARD. LOWS 67-71.
-GIH

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...

THROUGH EARLY NEXT WEEK THE LATEST MODEL GUIDANCE CONTINUES TO
SUPPORT THE CURRENT FORECAST OF ABOVE NORMAL TEMPERATURES WITH
THUNDERSTORM CHANCES GENERALLY BELOW CLIMATOLOGY... 20-30%... MAINLY
IN THE AFTERNOON/EVENING. MID LEVEL RIDGING PERSISTS OVER THE
SOUTHEAST STATES WHILE A LARGE TROUGH SHIFTS SLOWLY EASTWARD THROUGH
NORTH CENTRAL NORTH AMERICA. THE LATEST GFS AMPLIFIES THIS TROUGH
SUFFICIENTLY AS MOVES INTO EASTERN CANADA SUCH THAT IT PUSHES A COLD
FRONT SOUTH THROUGH NC SUNDAY NIGHT... HOWEVER THE PREVIOUS GFS AND
THE RECENT ECMWF SUPPORT A LESS AMPLIFIED SOLUTION WITH MORE RIDGING
HOLDING OVER THE SOUTHEAST. WILL STAY WITH THIS COURSE AND COOL
TEMPS DOWN ONLY MARGINALLY FOR TUESDAY... WITH CHANCE POPS. -GIH

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 400 AM WEDNESDAY...

A BOUNDARY MOVING THROUGH THE AREA COMBINED WITH ABUNDANT SURFACE
MOISTURE AND MID/UPPER LEVEL DISTURBANCES WILL LEAD TO PERSISTENT
CHANCE FOR RAIN THROUGH TONIGHT. MVFR CONDITIONS WILL GRADUALLY
LOWER TO IFR...OCCASIONAL LIFR IN RAIN...DRIZZLE AND FOG THROUGH THE
MORNING INTO THE EARLY AFTERNOON.

CONDITIONS WILL IMPROVE TO MVFR THURSDAY AND CONTINUE INTO FRIDAY
DUE TO PREVAILING MOIST EASTERLY FLOW.

A TROUGH MOVING THROUGH THE AREA FRIDAY INTO SATURDAY COMBINED WITH
MOISTURE AND UPPER LEVEL DISTURBANCES WILL RESULT IN DIURNAL SHOWERS
AND THUNDERSTORMS. STRATUS AND FOG POSSIBILE EACH MORNING.
CONDITIONS WILL GRADUALLY IMPROVE SUNDAY AS WEAK HIGH PRESSURE
BUILDS INTO THE AREA FROM THE WEST.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...RHJ

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RALEIGH NC
418 AM EDT WED SEP 10 2008

NCZ007>011-021>028-038>043-073>078-083>086-088-089-110900-
PERSON-GRANVILLE-VANCE-WARREN-HALIFAX-FORSYTH-GUILFORD-ALAMANCE-
ORANGE-DURHAM-FRANKLIN-NASH-EDGECOMBE-DAVIDSON-RANDOLPH-CHATHAM-WAKE-
JOHNSTON-WILSON-STANLY-MONTGOMERY-MOORE-LEE-HARNETT-WAYNE-ANSON-
RICHMOND-SCOTLAND-HOKE-CUMBERLAND-SAMPSON-
418 AM EDT WED SEP 10 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

AREAS OF RAIN AND THUNDERSTORMS ARE EXPECTED OVER CENTRAL NORTH
CAROLINA TODAY INTO THIS EVENING... AS A COLD FRONT APPROACHES
FROM THE NORTH. DUE TO THE HEAVY RAIN BROUGHT BY TROPICAL STORM
HANNA... THE GROUND REMAINS MOIST... AND STREAMS CONTINUE TO RUN
HIGH ACROSS CENTRAL NORTH CAROLINA. THIS ADDITIONAL RAINFALL MAY
PRODUCE LOCALIZED FLOODING IN URBAN AREAS AND IN LOCATIONS WITH
POOR DRAINAGE SUCH AS CONTRUCTION ZONES. TOTAL RAINFALL OF ONE
HALF TO AROUND ONE INCH... WITH LOCALLY HIGHER AMOUNTS... IS
EXPECTED THROUGH TONIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

GIH