Special Weather Statement, NWS Raleigh, NC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
935 PM EDT SUN JUL 7 2013

.SYNOPSIS...
A WEAKENING UPPER LEVEL LOW WILL PROGRESS EAST ACROSS THE MID-
ATLANTIC THROUGH EARLY MONDAY. BROAD CYCLONIC FLOW ALOFT WILL
PREVAIL OVER THE EASTERN UNITED STATES THROUGH MID WEEK...WITH
ANOTHER UNSEASONABLY DEEP UPPER LEVEL TROUGH DIGGING SOUTHEAST INTO
THE EASTERN UNITED STATES BY LATE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM SUNDAY...

AN AREA OF SHOWERS AND THUNDERSTORMS IS CURRENTLY AFFECTING THE
WESTERN HALF OF THE FORECAST AREA AND IS EXPECTED TO SLOWLY
PROPAGATE TO THE EAST OVER THE NEXT SEVERAL HOURS. SEVERAL OF THE
STORMS BECAME BETTER ORGANIZED OVER THE LAST COUPLE OF HOURS AS THEY
MOVED INTO A REGION OF BETTER INSTABILITY AND ALSO ACCORDING TO THE
SPC MESO ANALYSIS PAGE...DEEP LAYER SHEAR INCREASED TO 30-35 KNOTS
OVER THE NORTHWESTERN PORTION OF THE FORECAST AREA (WHICH IS DUE TO
THE INCREASING FLOW AHEAD OF THE UPPER TROUGH/LOW THAT IS FINALLY
LIFTING OUT OF THE MIDWEST). IN ADDITION...MODELS SHOW AN UPPER
LEVEL PERTURBATION LIFTING NORTH AND EAST ACROSS THE WESTERN
PORTION OF NC IN THE INCREASED SOUTHWESTERLY FLOW ALOFT. ALL OF THIS
SHOULD SUPPORT PRECIP THROUGH MUCH OF THE OVERNIGHT HOURS...ALTHOUGH
THE COVERAGE AND INTENSITY SHOULD GRADUALLY DECREASE AS NOCTURNAL
STABILIZATION INCREASES. OVERNIGHT LOWS WILL ONCE AGAIN BE NEAR 70
DEGREES...GIVE OR TAKE A DEGREE OR TWO.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 240 PM SUNDAY...

AS THE UPPER LEVEL LOW MAKES ITS WAY ACROSS PA AND INTO NEW ENGLAND
MONDAY AND MONDAY NIGHT...THE ASSOCIATED TROUGH WILL MOVE INTO
CENTRAL NC...THUS DAMPENING THE HIGH AND PUSHING THE RIDGE AXIS
SOUTH AND EAST. THE MAIN SHOWER ACTIVITY WILL SHIFT SLOWLY EASTWARD
THROUGH THE DAY AND INTO THE EVENING MONDAY AS ADDITIONAL SHORTWAVE
DISTURBANCES MOVE OVER THE AREA. HIGHEST PRECIP CHANCES COINCIDE
WITH PEAK HEATING...AND WILL DECREASE SUBSTANTIALLY AFTER SUNSET.
HIGH TEMPS WILL BE SIMILAR TO TODAY...MID 80S NW INCREASING TO NEAR
90 IN THE EAST. OVERNIGHT LOWS WILL AGAIN BE SIMILAR TO PREVIOUS
NIGHTS...MAINLY IN THE LOW 70S.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 230 PM SUNDAY...

FOR TUESDAY/TUESDAY NIGHT: VERY WEAK MID LEVEL TROUGH AXIS HOLDS
OVER THE EAST COAST WHILE A SUBTLE SURFACE TROUGH HOLDS OVER THE NC
PIEDMONT. ABOVE-NORMAL DEEP MOISTURE PERSISTS ESPECIALLY SOUTH AND
EAST OF THE TROUGH WITH PW VALUES RANGING FROM 1.7-2.0 INCHES FROM
NW TO SE OVER CENTRAL NC. THE WEAK WIND FIELD (PROJECTED WINDS NO
GREATER THAN 15 KTS BELOW 400 MB) THROUGHOUT THE MOIST COLUMN
COMBINED WITH DAYTIME DESTABILIZATION (MLCAPE PEAKING AT 1200-2000
J/KG) SUGGEST SCATTERED STORMS DEVELOPING IN THE AFTERNOON WITH SLOW
MOVEMENT AND THE POTENTIAL TO DUMP SOME HEAVY RAIN... GIVEN THE
LCL-TO-0C LAYER DEPTH APPROACHING 3.8-4 KM. THE GFS/NAM/ECMWF
GENERALLY FAVOR BETTER COVERAGE OVER THE SOUTHEAST CWA IN
CONJUNCTION WITH THE GREATEST MOISTURE AND INSTABILITY... SO WILL
EDGE POPS HIGHER THERE THAN IN THE REST OF THE CWA. SHOWERS/STORMS
SHOULD FOLLOW A TYPICAL DIURNAL PATTERN OF TAPERING DOWN AFTER
NIGHTFALL... ALTHOUGH WITH ANOMALOUSLY HIGH MOISTURE CONTINUING TO
POOL OVER CENTRAL NC... A FEW MEANDERING SHOWERS AND ISOLATED STORMS
MAY PERSIST OVERNIGHT. HIGHS 86-90. LOWS 70-73.

FOR WEDNESDAY/WEDNESDAY NIGHT: THIS LOOKS TO BE THE TIME FRAME WITH
A RELATIVE MINIMUM IN RAIN CHANCES... BUT CERTAINLY NOT ZERO
CONSIDERING THE STILL-HIGH PW VALUES NEAR 2.0 INCHES. THE WESTERLIES
TAKE A DIP INTO THE GREAT LAKES AS THE TROUGH BEGINS TO DIG TO OUR
NORTHWEST... RESULTING A SLIGHT DOWNSTREAM REBOUNDING IN HEIGHTS
OVER NC. GFS FORECAST SOUNDINGS SHOW A PERIOD OF MID LEVEL DRYING
BETWEEN 800 AND 500 MB MAINLY IN THE EASTERN CWA... WHERE BOTH THE
GFS AND ECMWF SHOW FAIRLY LOW QPF. WILL LEAVE IN CHANCE POPS...
SKEWED HIGHER IN THE TRIAD AND LOWER IN THE SOUTHEAST... FOCUSED ON
THE AFTERNOON/EVENING. HIGHS 87-91 AS THICKNESSES STAY NEAR
CLIMATOLOGY. THE DEEPENING MID LEVEL TROUGH TO OUR WEST RESULTS IN
AN UPTICK IN MID LEVEL WINDS OVER NW NC WEDNESDAY NIGHT... AND WITH
MOISTURE REMAINING HIGH OR EVEN INCREASING A BIT OVER OUR NW CWA
OVERNIGHT... WILL HOLD ONTO CHANCE POPS HERE WITH JUST A SLIGHT
CHANCE ELSEWHERE. LOWS 70-74.

FOR THURSDAY THROUGH SUNDAY: CONFIDENCE IS IMPROVING THAT THIS WILL
BE A FAIRLY WET PERIOD. THE LONGWAVE TROUGH DIGS FURTHER THROUGH THE
EASTERN GREAT LAKES AND OH VALLEY ON THURSDAY AS THE SURFACE COLD
FRONT MOVES IN FROM THE NW... AND THE INCREASING DYNAMICS AND DEEP
MOISTURE FLUX OVER NC WILL BRING INCREASING SHOWER/STORM COVERAGE
FROM NW TO SE AS WE HEAD THROUGH THURSDAY AFTERNOON/NIGHT. THE
MODELS CLOSE OFF A LOW TO OUR NORTHWEST... OVER WV/ERN KY/ERN TN...
ON FRIDAY BEFORE DROPPING IT DOWN TO NRN GA/AL/MS OVER THE WEEKEND.
SUCH A CLOSED LOW THAT FAR SOUTH IS HIGHLY UNUSUAL FOR THIS TIME OF
YEAR (GEFS FORECAST 500 MB HEIGHTS OVER 2 STANDARD DEVIATIONS BELOW
NORMAL OVER THE SOUTHEAST STATES)... SO IT IS SURPRISING HOW GOOD
THE AGREEMENT IS BETWEEN THE OP GFS (12Z/07) AND ECMWF (00Z/07).
WITH THE LOSS OF EASTWARD PUSH... THE SURFACE FRONT IS LIKELY TO
STALL OUT OVER CENTRAL NC... AND WITH A STRENGTHENING AND DEEPENING
SOUTHERLY FLOW ALLOWING 2.0+ INCH PW VALUES TO STREAK OVER CENTRAL
NC FROM THURSDAY NIGHT THROUGH AT LEAST SATURDAY... WITH SOME DRYING
POSSIBLE SUNDAY AS A LARGE AND STRONG MID LEVEL CYCLONE BUILDS FROM
OFF THE CANADIAN MARITIMES SOUTHWESTWARD INTO NC. WILL KEEP HIGH
RAIN CHANCES FOR THURSDAY NIGHT THROUGH SATURDAY... A BIT HIGHER IN
THE AFTERNOON/EVENING BUT NOT YIELDING MUCH AT NIGHT... DROPPING
BACK TOWARD CLIMATOLOGICAL POPS ON SUNDAY. EXPECT QUITE A BIT OF
CLOUDINESS THROUGH THIS PERIOD WITH HUMID CONDITIONS REDUCING THE
DIURNAL TEMP RANGE. LOWS AROUND 70-75 AND HIGHS IN THE LOW-MID 80S.
-GIH

&&

.AVIATION /00Z MONDAY THROUGH THURSDAY/...
AS OF 750 PM SUNDAY...

SCATTERED SHOWERS AND A FEW STORMS OVER THE WESTERN PIEDMONT WILL
SLOWLY TRANSLATE EAST THIS EVENING AS A TROUGH OF LOW PRESSURE MOVES
INTO THE AREA.  THIS WILL BRING A CHANCE OF A BRIEF DOWNPOUR AND
STRONG WIND GUSTS TO KGSO/KINT THROUGH 06Z...AND POSSIBLY AS FAR
EAST AS KRDU THROUGH 09Z.  MEANWHILE...MOISTURE POOLING ALONG THIS
TROUGH WILL LIKELY CAUSE SOME AREAS OF STRATUS TO DEVELOP BY
09Z...THOUGH CONFIDENCE IN WIDESPREAD MVFR/IFR CEILINGS IS LOW.
MOSTLY VFR CONDITIONS SHOULD REDEVELOP BY MID MORNING...AROUND
14Z...AND PERSIST INTO THE AFTERNOON HOURS.  SHOWERS AND STORMS ARE
LIKELY AGAIN MONDAY AFTERNOON...WITH GREATER COVERAGE NEAR
KRDU/KRWI/KFAY.

OUTLOOK...
THE WEATHER PATTERN WILL BE FAIRLY PERSISTENT THROUGH MUCH OF THE
UPCOMING WEEK...WITH A PERIOD OF STRATUS/FOG POSSIBLE EACH MORNING
AND SCATTERED SHOWERS AND STORMS DURING THE AFTERNOON.

&&

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

&&

SYNOPSIS...KRR/VINCENT
NEAR TERM...KRR
SHORT TERM...KC
LONG TERM...HARTFIELD
AVIATION...BLS

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE RALEIGH NC
947 PM EDT SUN JUL 7 2013

NCZ007>011-021>028-038>043-073>078-083>086-088-089-090200-
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-
947 PM EDT SUN JUL 7 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...THROUGH TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

AN UNSETTLED WEATHER PATTERN IS EXPECTED THIS WEEK... ESPECIALLY
FOR THURSDAY THROUGH SATURDAY. GIVEN THE RECENT PERIOD OF WET
WEATHER AND ELEVATED RIVER LEVELS... FLOODING WILL BE POSSIBLE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
746 PM EDT SUN JUL 7 2013

NCZ023-024-080045-
ALAMANCE-ORANGE-
746 PM EDT SUN JUL 7 2013

...A STRONG THUNDERSTORM WILL MOVE ACROSS ORANGE AND ALAMANCE
COUNTIES THROUGH 845 PM EDT...

AT 746 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 6 MILES
SOUTH OF ALAMANCE...OR ABOUT 9 MILES SOUTHWEST OF GRAHAM...MOVING
NORTHEAST AT 20 MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...ALAMANCE...
SAXAPAHAW...AND...BURLINGTON...SWEPSONVILLE...AND...GRAHAM...HAW
RIVER...MEBANE...EFLAND.

HAZARDS INCLUDE...
GUSTY WINDS OF 30 TO 40 MPH.
HEAVY RAINFALL AND MINOR FLOODING.

SEEK SHELTER IN A NEARBY BUILDING OR VEHICLE. WIND GUSTS AS HIGH AS
40 MPH ARE CAPABLE OF KNOCKING DOWN TREE LIMBS AND BLOWING AROUND
TRASH CANS...POTTED PLANTS...LAWN FURNITURE AND OTHER LIGHT OUTDOOR
OBJECTS. LOCALLY HEAVY RAIN WILL QUICKLY REDUCE VISIBILITY AND RESULT
IN PONDING OF WATER ON ROADWAYS. DRIVERS ARE URGED TO SLOW DOWN AND
USE EXTRA CAUTION TO AVOID HYDROPLANING.

&&

LAT...LON 3625 7922 3614 7899 3584 7948 3590 7955
      3592 7954 3608 7954 3625 7950
TIME...MOT...LOC 2346Z 234DEG 16KT 3596 7947

KRR

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
826 PM EDT SUN JUL 7 2013

NCZ039-074-075-080130-
MONTGOMERY-MOORE-RANDOLPH-
826 PM EDT SUN JUL 7 2013

...A STRONG THUNDERSTORM WILL MOVE ACROSS RANDOLPH...MOORE AND
MONTGOMERY COUNTIES THROUGH 930 PM EDT...

AT 826 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 6 MILES
WEST OF TROY...MOVING NORTHEAST AT 20 MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...TROY...STAR...AND...
BISCOE...STEEDS.

HAZARDS INCLUDE...
GUSTY WINDS OF 40 TO 50 MPH.
HEAVY RAINFALL AND MINOR FLOODING.

SEEK SHELTER IN A NEARBY BUILDING OR VEHICLE. WIND GUSTS AS HIGH AS
50 MPH ARE CAPABLE OF KNOCKING DOWN SMALL OR WEAKENED TREES AND
BLOWING AROUND TRASH CANS...POTTED PLANTS...LAWN FURNITURE AND OTHER
LIGHT OUTDOOR OBJECTS. LOCALLY HEAVY RAIN WILL QUICKLY REDUCE
VISIBILITY AND RESULT IN PONDING OF WATER ON ROADWAYS. DRIVERS ARE
URGED TO SLOW DOWN AND USE EXTRA CAUTION TO AVOID HYDROPLANING.

&&

LAT...LON 3540 8009 3563 7977 3530 7949 3523 8003
      3531 8008 3536 8007 3537 8005
TIME...MOT...LOC 0026Z 239DEG 16KT 3534 7997

22

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
841 PM EDT SUN JUL 7 2013

NCZ024-025-080145-
DURHAM-ORANGE-
841 PM EDT SUN JUL 7 2013

...A STRONG THUNDERSTORM WILL MOVE ACROSS ORANGE AND DURHAM COUNTIES
THROUGH 945 PM EDT...

AT 840 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER
CANE CREEK RESERVOIR...OR ABOUT 8 MILES WEST OF CHAPEL HILL...MOVING
NORTHEAST AT 30 MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...EFLAND...
HILLSBOROUGH...SCHLEY...DURHAM...GORMAN AND BAHAMA.

HAZARDS INCLUDE...
GUSTY WINDS OF 40 TO 50 MPH.
HEAVY RAINFALL AND MINOR FLOODING.

SEEK SHELTER IN A NEARBY BUILDING OR VEHICLE. WIND GUSTS AS HIGH AS
50 MPH ARE CAPABLE OF KNOCKING DOWN SMALL OR WEAKENED TREES AND
BLOWING AROUND TRASH CANS...POTTED PLANTS...LAWN FURNITURE AND OTHER
LIGHT OUTDOOR OBJECTS. LOCALLY HEAVY RAIN WILL QUICKLY REDUCE
VISIBILITY AND RESULT IN PONDING OF WATER ON ROADWAYS. DRIVERS ARE
URGED TO SLOW DOWN AND USE EXTRA CAUTION TO AVOID HYDROPLANING.

&&

LAT...LON 3616 7881 3612 7880 3609 7881 3607 7877
      3596 7872 3588 7923 3595 7927 3602 7926
      3624 7910 3624 7897
TIME...MOT...LOC 0040Z 234DEG 27KT 3598 7915

KRR

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
1002 PM EDT SUN JUL 7 2013

NCZ008-009-080245-
GRANVILLE-VANCE-
1002 PM EDT SUN JUL 7 2013

...A STRONG THUNDERSTORM WILL MOVE ACROSS VANCE AND GRANVILLE
COUNTIES THROUGH 1045 PM EDT...

AT 1002 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER
OAK HILL...OR ABOUT 7 MILES SOUTHEAST OF VIRGILINA...MOVING EAST AT
20 MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...STOVALL...KERR
LAKE...TUNGSTEN.

HAZARDS INCLUDE...
GUSTY WINDS OF 30 TO 40 MPH.

SEEK SHELTER IN A NEARBY BUILDING OR VEHICLE. WIND GUSTS AS HIGH AS
40 MPH ARE CAPABLE OF KNOCKING DOWN TREE LIMBS AND BLOWING AROUND
TRASH CANS...POTTED PLANTS...LAWN FURNITURE AND OTHER LIGHT OUTDOOR
OBJECTS. LOCALLY HEAVY RAIN WILL QUICKLY REDUCE VISIBILITY AND RESULT
IN PONDING OF WATER ON ROADWAYS. DRIVERS ARE URGED TO SLOW DOWN AND
USE EXTRA CAUTION TO AVOID HYDROPLANING.

&&

LAT...LON 3648 7838 3643 7843 3636 7880 3639 7880
      3641 7880 3654 7879 3655 7877 3655 7837
TIME...MOT...LOC 0202Z 250DEG 19KT 3647 7869

22!

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
1044 PM EDT SUN JUL 7 2013

NCZ007-023-024-080345-
ALAMANCE-ORANGE-PERSON-
1044 PM EDT SUN JUL 7 2013

...A STRONG THUNDERSTORM WILL MOVE ACROSS PERSON...ORANGE AND
ALAMANCE COUNTIES THROUGH 1145 PM EDT...

AT 1044 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER
MEBANE...OR ABOUT 7 MILES EAST OF GRAHAM...MOVING NORTHEAST AT 30
MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...CARR...BUSHY FORK...
ROXBORO.

HAZARDS INCLUDE...
GUSTY WINDS OF 30 TO 40 MPH.
DEADLY CLOUD TO GROUND LIGHTNING.
HEAVY RAINFALL AND MINOR FLOODING.

SEEK SHELTER IN A NEARBY BUILDING OR VEHICLE. WIND GUSTS AS HIGH AS
40 MPH ARE CAPABLE OF KNOCKING DOWN TREE LIMBS AND BLOWING AROUND
TRASH CANS...POTTED PLANTS...LAWN FURNITURE AND OTHER LIGHT OUTDOOR
OBJECTS. LOCALLY HEAVY RAIN WILL QUICKLY REDUCE VISIBILITY AND RESULT
IN PONDING OF WATER ON ROADWAYS. DRIVERS ARE URGED TO SLOW DOWN AND
USE EXTRA CAUTION TO AVOID HYDROPLANING.

&&

LAT...LON 3636 7880 3633 7880 3624 7891 3624 7895
      3621 7895 3599 7924 3610 7942 3625 7932
      3625 7916 3654 7914 3655 7913 3655 7907
TIME...MOT...LOC 0244Z 218DEG 26KT 3611 7926

22

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
1121 PM EDT SUN JUL 7 2013

NCZ007-008-080415-
GRANVILLE-PERSON-
1121 PM EDT SUN JUL 7 2013

...A STRONG THUNDERSTORM WILL MOVE ACROSS PERSON AND GRANVILLE
COUNTIES THROUGH 1215 AM EDT...

AT 1121 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER
BUSHY FORK...OR ABOUT 9 MILES EAST OF PROSPECT HILL...MOVING
NORTHEAST AT 35 MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...ROXBORO...SURL...OAK
HILL...AND KERR LAKE.

HAZARDS INCLUDE...
GUSTY WINDS UP TO 35 MPH.
DEADLY CLOUD TO GROUND LIGHTNING.
HEAVY RAINFALL AND MINOR FLOODING.

HEAVY RAIN WILL RESULT IN PONDING OF WATER ON ROADWAYS...STANDING
WATER IN LOW LYING AREAS AND MINOR FLOODING OF CREEKS...STREAMS AND
AREAS OF POOR DRAINAGE. DRIVERS ARE URGED TO SLOW DOWN AND USE EXTRA
CAUTION TO AVOID HYDROPLANING...ESPECIALLY IN URBAN AREAS WHERE
PROLONGED HEAVY RAIN CAN QUICKLY LEAD TO FLASH FLOODING.

&&

LAT...LON 3655 7845 3654 7845 3652 7847 3652 7849
      3642 7852 3636 7865 3624 7887 3624 7910
      3633 7916 3655 7885
TIME...MOT...LOC 0321Z 232DEG 29KT 3630 7902

VINCENT