Special Weather Statement, NWS Raleigh, NC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
345 AM EDT SUN MAR 25 2012

.SYNOPSIS...
UNSETTLED WEATHER WILL PERSIST TODAY AS A POTENT UPPER LEVEL LOW
PROGRESSES EAST OVER THE CAROLINAS. MUCH DRIER CONDITIONS WILL
RETURN FOR MONDAY AND TUESDAY AS UPPER LEVEL HIGH PRESSURE BUILDS IN
FROM THE WEST.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 345 AM SUNDAY...

OVERVIEW:
A POTENT UPPER LEVEL LOW CENTERED OVER FAR SOUTHWEST NC AT 06Z THIS
MORNING WILL TRACK EAST SOUTHEAST TO CAPE FEAR BY 00Z THIS
EVENING...PROGRESSING OFFSHORE BY 12Z MONDAY MORNING. IN THE LOWER
LEVELS...A WEAK/BAGGY SURFACE LOW CENTERED OVER THE CAROLINAS AT 06Z
WILL TRACK EAST OF THE I-95 CORRIDOR THIS AFTERNOON BEFORE
PROGRESSING OFFSHORE WITH THE UPPER LEVEL LOW LATE TONIGHT.

TEMPERATURES:
HIGH TEMPS TODAY WILL BE PRIMARILY BE A FUNCTION OF TWO FACTORS...
CLOUD COVER AND SCATTERED CONVECTION ASSOCIATED WITH THE UPPER LEVEL
LOW PROGRESSING THROUGH THE AREA. ALTHOUGH SOME UNCERTAINTY PERSISTS
W/REGARD TO THE EXACT TRACK OF THE UPPER LOW...THE BULK OF MODEL
GUIDANCE INDICATES THAT IT WILL GENERALLY TRACK EAST/SE FROM
ASHEVILLE TO CAPE FEAR THROUGH 00Z THIS EVENING. ON THAT TRACK...
THE N/NW PIEDMONT WOULD BE MOST LIKELY TO SEE BROKEN/OVERCAST
MID-LEVEL CLOUD COVER PERSIST THROUGH THE MAJORITY OF THE DAY...AND
THE SOUTHEAST COASTAL PLAIN WOULD BE MOST LIKELY TO SEE A PERIOD OF
PARTLY TO MOSTLY SUNNY SKIES IN ASSOC/W A RELATIVELY DRIER MID-LEVEL
AIRMASS ON THE SOUTHERN/EASTERN PERIPHERY OF THE UPPER LOW. AS A
RESULT...EXPECT THE COOLEST READINGS IN THE N/NW PIEDMONT AND THE
WARMEST IN THE SE COASTAL PLAIN. SCATTERED CONVECTION PROVIDES THE
LARGEST UNCERTAINTY WITH TEMPS TODAY. GIVEN DEWPOINTS IN THE MID
50S...EVAP COOLING ASSOC/W PRECIPITATION COULD EASILY PREVENT HIGHS
FROM EXCEEDING THE LOWER 60S IN AREAS WHERE CLOUD COVER/PRECIP ARE
MORE PERSISTENT...HOWEVER...UNCERTAINTY IN THE TIMING AND LOCATION
OF CONVECTION TODAY IS SUFFICIENT TO PRECLUDE TAKING THIS FACTOR
INTO ACCOUNT. WITH THE ABOVE IN MIND...AND WITH 1000-850 MB
THICKNESSES PROGGED IN THE 1355-1365 METER RANGE... EXPECT HIGHS TO
RANGE FROM THE UPPER 60S IN THE NW PIEDMONT TO THE LOWER/MID 70S IN
THE SE COASTAL PLAIN. WITH LINGERING MID-LEVEL CLOUD COVER ON THE
BACKSIDE OF THE DEPARTING UPPER LOW THROUGH AT LEAST 06Z...LOWS
TONIGHT WILL BE DRIVEN PRIMARILY BY THE ONSET OF LOW-LEVEL COLD
ADVECTION AND CLEARING IN THE 06-12Z TIME FRAME FROM NW-SE. EXPECT
LOWS TO RANGE FROM THE LOWER 50S NW TO MID 50S SE.

PRECIPITATION:
LIFT TODAY WILL BE PRESENT IN THE FORM OF DPVA ASSOCIATED WITH SMALL
AMPLITUDE SHORTWAVES ROTATING AROUND THE UPPER LEVEL LOW...MID-LEVEL
FRONTOGENESIS ON THE N/NW PERIPHERY OF THE H7 REFLECTION EXPECTED TO
TRACK ALONG THE NC/SC BORDER...AND SHALLOW LOW-LEVEL CONVERGENCE IN
VICINITY OF THE WEAK/BAGGY SURFACE LOW PROGRESSING EAST THROUGH THE
AREA. W/REGARD TO THERMODYNAMICS...500-1000 J/KG OF MLCAPE IS
EXPECTED THIS AFTERNOON OWING TO A RELATIVELY MOIST BOUNDARY LAYER
(DEWPOINTS MID 50S) AND STEEP MID-LEVEL LAPSE RATES UNDER THE COLD
POOL ALOFT (H5 TEMPS FALLING TO -21C). UNCERTAINTY PERSISTS W/REGARD
TO THE EXACT TIMING AND LOCATION OF PRECIPITATION TODAY...HOWEVER...
THE HIGH RESOLUTION WRF-NMM SIMULATED REF PRODUCT INDICATES THE BEST
CHANCE FOR PRECIP IN CENTRAL NC THROUGH 18Z THIS AFTERNOON WILL BE
IN THE FAR NORTHERN AND WESTERN PIEDMONT...CLOSER TO WHERE THE BEST
DPVA AND MID-LEVEL FRONTOGENESIS SHOULD BE. FURTHER SOUTH/EAST IN
THE SANDHILLS AND COASTAL PLAIN...ISOLD CONVECTION WILL BE POSSIBLE
AT THE LEAST. BETWEEN 18Z THIS AFTERNOON AND 06Z TONIGHT...THE BEST
CHANCE FOR PRECIP IS EXPECTED TO SHIFT FROM THE N/W PIEDMONT INTO
THE TRIANGLE AND COASTAL PLAIN AS THE THE BEST DPVA/MID-LEVEL
FRONTOGENESIS PROGRESSES EAST/ESE WITH THE UPPER LOW. WITH THE ABOVE
IN MIND...AFTER 20-40% PRECIP CHANCES EARLY THIS MORNING (HIGHEST
FAR WESTERN PIEDMONT) WILL INDICATE PRECIP CHANCES INCREASING TO
LIKELY (60%) IN THE FAR N/NW PIEDMONT FROM 15-21Z...WITH 20-50%
CHANCES ELSEWHERE (LOWEST EAST/SE COASTAL PLAIN) IN THAT TIME FRAME.
WILL SHOW PRECIP CHANCES INCREASING TO HIGH CHANCE OR LOW LIKELY
(50-60%) OVER THE TRIANGLE AND CENTRAL/NE COASTAL PLAIN BETWEEN 21Z
THIS AFTERNOON AND 06Z TONIGHT...WITH PRECIP CHANCES DECREASING AND
EVENTUALLY ENDING IN THE N/NW PIEDMONT IN THAT TIME FRAME. PRECIP
CHANCES SHOULD END IN THE SANDHILLS/COASTAL PLAIN BY 09-12Z AS THE
UPPER LOW PROGRESSES OFFSHORE AND HEIGHT RISES/SUBSIDENCE COMMENCE.

SEVERE THREAT:
DESPITE MUCAPE VALUES ANALYZED AT NO MORE THAN 100-250 J/KG PER 07Z
SPC MESOANALYSIS...AN IMPRESSIVE ISOLATED SEVERE STORM WAS PRESENT
WEST OF THE YADKIN RIVER OVER SOUTHERN IREDELL COUNTY AT 07Z THIS
MORNING...WITH 70 DBZ ECHOES UP TO 15 KFT...50 DBZ ECHOES UP TO 25
KFT...AND ECHO TOPS IN VICINITY OF 35 KFT. THIS ISOLD CELL IS
APPARENTLY BEING AIDED BY STRONG DPVA ASSOC/W A SHORTWAVE
PROGRESSING FROM UPSTATE SC TO CHARLOTTE AND THE FAR WESTERN
PIEDMONT ON THE EASTERN PERIPHERY OF THE UPPER LOW. INSTABILITY IN
THAT REGION IS LIKELY UNDER-REPRESENTED AND ENHANCED BY STRONG
LAYER-LIFTING (CONVECTIVE INSTABILITY) AND MID-LEVEL UPDRAFT
ROTATION OWING TO 35-40 KT OF 0-6 KM BULK SHEAR. WITH THIS IN
MIND...AN ISOLD THREAT OF SEVERE HAIL CANNOT BE RULED OUT BETWEEN
ROUGHLY 08-10Z IN FORSYTH/DAVIDSON COUNTIES...CLOSE TO THE TRACK OF
THE AFOREMENTIONED SHORTWAVE. BETWEEN 10-18Z...0-6KM BULK SHEAR
VALUES OVER CENTRAL NC WILL DECREASE TO ~20 KT OR LESS FROM
WEST-EAST AS THE HEIGHT GRADIENT WEAKENS IN VICINITY OF THE UPPER
LOW...AND THE THREAT FOR ORGANIZED CONVECTION WILL END FROM
WEST-EAST IN THAT TIME FRAME. ALTHOUGH BULK SHEAR VALUES WILL
INCREASE TO 35-45 KT AGAIN FROM WEST-EAST BETWEEN 18-06Z IN ASSOC/W
NNE/NE MID-LEVEL FLOW ON THE BACKSIDE OF THE UPPER LOW...THE BEST
DPVA/THERMODYNAMICS SHOULD REMAIN ON ITS EASTERN PERIPHERY...AND DO
NOT ANTICIPATE A THREAT FOR ORGANIZED CONVECTION LATER THIS AFT/EVE
AT THIS TIME. DESPITE WEAKENING DEEP LAYER SHEAR AS MENTIONED
ABOVE...GIVEN STEEP LOW/MID-LEVEL LAPSE RATES AND VERY COLD TEMPS
ALOFT...SMALL HAIL AND GUSTY WINDS WILL CERTAINLY BE POSSIBLE WITH
ANY STORMS TODAY...PARTICULARLY DURING THE AFTERNOON. -VINCENT

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 255 AM SUNDAY...

THE LATEST GFS/EUROPEAN MODELS ARE FAVORED WITH THE TIMING/STRENGTH
OF THE UPPER LOW THAT WILL BE MOVING AWAY FROM OUR REGION ON MONDAY.
STRONG SUBSIDENCE IN THE REAR OF THE UPPER LOW WILL COMBINE WITH A
DOWNSLOPE FLOW FROM THE NNW OF 10-15 MPH OFF THE BLUE RIDGE INTO THE
PIEDMONT TO BRING MOSTLY SUNNY SKIES TO CENTRAL NC MONDAY. MODELS
ARE IN GOOD AGREEMENT IN THE TIMING OF A SURFACE COLD FRONT THAT IS
FORECAST TO PUSH SOUTH THROUGH NC MONDAY AFTERNOON. WITH STRONG
DRYING EXPECTED ALONG AND BEHIND THE FRONT... DEW POINTS ARE
FORECAST TO DROP OFF INTO THE 30S BY MID TO LATE AFTERNOON. HIGHS
ARE EXPECTED TO REACH 75 TO 80 WITH THE WARMEST READINGS EXPECTED
ACROSS THE SANDHILLS.

WITH HIGH CONFIDENCE... THE FORECAST FOR MONDAY NIGHT AND TUESDAY IS
FOR BREEZY AND MUCH COOLER CONDITIONS WITH MOSTLY CLEAR SKIES MONDAY
EVENING... WITH WINDS EXPECTED TO DIE OFF BY LATE EVENING. A STRONG
HIGH PRESSURE WILL BUILD SOUTH FROM THE EASTERN GREAT LAKES DEEP
INTO GA BY TUESDAY. ANOTHER ISSUE MAY BE A POTENTIAL FROST ADVISORY
ACROSS THE NORTH MONDAY NIGHT AS TEMPERATURES CRASH AFTER THE WINDS
DIE OFF. LOWS OF 35-40 EXPECTED NORTH... WITH AROUND 40 IN THE SE.
THE MAIN THREAT WILL BE SCATTERED FROST IN LOW LYING AND NON-URBAN
AREAS OF THE PIEDMONT BETWEEN 400 AM AND SUNRISE. HIGHS TUESDAY WILL
BE MOSTLY IN THE 60S.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...

A SPRING TEMPERATURE SEE-SAW IS EXPECTED WEDNESDAY THROUGH LATE
WEEK.

A RAPID WARM-UP WEDNESDAY WILL BRING HIGHS BACK INTO THE MID 70S TO
AROUND 80. THIS WARMTH WILL PEAK THURSDAY WHEN THERE MAY BE A CHANCE
OF A SHOWER OR THUNDERSTORM DEPENDING ON THE TIMING OF THE NEXT COLD
FRONT. THIS WARMTH WILL BE FOLLOWED BY ANOTHER QUICK SHOT OF COOLER
AIR WITH HIGHS BACK INTO THE 65-72 RANGE EXPECTED BY FRIDAY. MOST
GUIDANCE SUGGESTS LOWS SHOULD STAY ABOVE THE FROST THRESHOLD DURING
THE NEXT COOL SNAP FRIDAY MORNING (MOSTLY 38+ DEGREES).

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 215 AM SUNDAY...

24-HR TAF PERIOD:
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL PERSIST THROUGH
THE TAF PERIOD AS A POTENT UPPER LEVEL LOW PROGRESSES EAST/SE
THROUGH THE CAROLINAS. TRANSIENT SUB-VFR CONDITIONS CAN BE EXPECTED
IN ASSOC/W ANY CONVECTION THROUGHOUT THE TAF PERIOD. ADDITIONALLY...
MVFR/IFR CEILINGS AND/OR MVFR VISBYS WILL BE POSSIBLE AT ANY TAF
SITE THROUGH 12Z THIS MORNING IN ASSOC/W A RESIDUAL MOIST BOUNDARY
LAYER AND NOCTURNAL COOLING. WINDS WILL BE LIGHT/VARIABLE THROUGH
18-21Z THIS AFTERNOON...EVENTUALLY BECOMING NORTHWEST AT 5-10 KT BY
THE END OF THE TAF PERIOD AS THE UPPER LEVEL LOW AND IT'S SURFACE
REFLECTION PROGRESS OFFSHORE THE CAROLINA COAST AND HIGH PRESSURE
BEGINS BUILDING INTO THE AREA FROM THE NORTHWEST.

LOOKING AHEAD:
CLEAR SKIES/VFR CONDITIONS ASSOCIATED WITH AN UPPER LEVEL RIDGE AND
SURFACE HIGH PRESSURE WILL PREVAIL OVER CENTRAL NC MONDAY/TUESDAY.
MVFR/IFR CEILINGS WILL BE POSSIBLE WEDNESDAY MORNING AS HIGH
PRESSURE SHIFTS OFFSHORE AND A MOIST SOUTHERLY RETURN FLOW DEVELOPS.
SUB-VFR CONDITIONS WILL ALSO BE POSSIBLE WEDNESDAY NIGHT AND
THURSDAY IN ASSOC/W A BACKDOOR COLD FRONT EXPECTED TO PROGRESS
SLOWLY SOUTHWARD THROUGH CENTRAL NC. -VINCENT

&&

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

&&

SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE RALEIGH NC
225 AM EDT SUN MAR 25 2012

NCZ007>011-021>028-038>043-073>078-083>086-088-089-260630-
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-
225 AM EDT SUN MAR 25 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...THROUGH TONIGHT.

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL PERSIST TODAY AS A
POTENT UPPER LEVEL LOW PROGRESSES EAST THROUGH THE CAROLINAS.
ALTHOUGH SEVERE WEATHER IS UNLIKELY...ANY STORMS THAT DEVELOP WILL
BE CAPABLE OF PRODUCING SMALL HAIL AND GUSTY WINDS...PRIMARILY
DURING THE AFTERNOON.

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

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

VINCENT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
1209 AM EDT SUN MAR 25 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0753 PM     HAIL             3 ESE BUSHY FORK        36.29N  79.04W
03/24/2012  M0.25 INCH       PERSON             NC   STORM CHASER

&&

EVENT NUMBER RAH1200140

BLAES

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
1217 AM EDT SUN MAR 25 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0744 PM     HAIL             4 SSE BUSHY FORK        36.26N  79.04W
03/24/2012  M0.75 INCH       PERSON             NC   TRAINED SPOTTER

            DIME SIZE HAIL FALLING ALONG ROUTE 157 AT
            HOLEMAN-ASHLEY ROAD.4

&&

EVENT NUMBER RAH1200141

BLAES

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
430 AM EDT SUN MAR 25 2012

NCZ021-038-250930-
FORSYTH-DAVIDSON-
INCLUDING THE CITIES OF...WINSTON-SALEM...LEXINGTON
430 AM EDT SUN MAR 25 2012

...AN ISOLATED SEVERE THUNDERSTORM OVER NORTHERN ROWAN COUNTY MAY
AFFECT FAR NORTHWEST DAVIDSON AND WESTERN FORSYTH COUNTIES
BY 515 AM...

AT 430 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN
ISOLATED SEVERE STORM WITH A HISTORY OF PRODUCING LARGE AMOUNTS OF
QUARTER TO GOLF BALL SIZE HAIL IN NORTHERN ROWAN COUNTY...MOVING
NORTHEAST AT 15 MPH. IF THE STORM MAINTAINS ITS CURRENT TRACK AND
INTENSITY...A SEVERE THUNDERSTORM WARNING WILL BE NEEDED FOR
LOCATIONS ALONG THE YADKIN RIVER IN FAR NORTHWEST DAVIDSON COUNTY
AND WESTERN FORSYTH COUNTY.

VINCENT

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
557 AM EDT SUN MAR 25 2012

NCZ022-251045-
GUILFORD-
557 AM EDT SUN MAR 25 2012

...A STRONG THUNDERSTORM WILL MOVE ACROSS GUILFORD COUNTY THROUGH 645
AM EDT...

AT 555 AM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER
PLEASANT GARDEN...OR ABOUT 8 MILES NORTH OF RANDLEMAN...MOVING NORTH
AT 15 MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...PLEASANT GARDEN...
FOREST OAKS...GREENSBORO...MCLEANSVILLE...AND LAKE TOWNSEND.

HAZARDS INCLUDE...
PEA SIZE HAIL.
DEADLY CLOUD TO GROUND LIGHTNING.
HEAVY RAINFALL AND MINOR FLOODING.

THIS STORM WILL PRODUCE LOCALLY HEAVY RAINFALL...WHICH WILL RESULT
IN MINOR FLOODING OF URBAN AND LOW LYING AREAS. MOTORISTS ARE URGED
TO SLOW DOWN AND USE EXTRA CAUTION TO AVOID HYDROPLANING...
ESPECIALLY ALONG THE INTERSTATE 40 AND INTERSTATE 85 CORRIDOR IN
GUILFORD COUNTY.

&&

LAT...LON 3625 7955 3590 7960 3592 7991 3625 7985
TIME...MOT...LOC 0955Z 189DEG 15KT 3595 7977

VINCENT