Severe Thunderstorm Warning 116, NWS Raleigh, NC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
155 PM EDT WED OCT 13 2004

.SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)...
ISOLATED SEVERE THREAT CONTINUES IN WARM SECTOR AHEAD OF A COLD
FRONT EARLY THIS EVENING. A NEAR STATIONARY FRONTAL BOUNDARY ACROSS
THE NORTHERN HALF WILL MAINTAIN LOW LEVEL SHEAR. SPC MESOANALYSES
SHOW INCREASING SFC BASED INSTABILITY IN THE SOUTHERN HALF.  LOW
LFC/LCLS SUPPORT DEEP CONVECTION AND POTENTIAL FOR SUPERCELLS MAINLY
SE QUADRANT. MODEST INSTABILITY AT MID LEVELS AND DRYING ALOFT WILL
BE LIMITING FACTORS WITH POPS OF 50-60 PERCENT THIS EVENING
DECREASING TO LESS THAN 30 PERCENT OVERNIGHT. THE COLD FRONT AND
UPPER TROUGH SHOULD EXIT THE CWA BY 06Z WITH MODERATE DRYING OF THE
AIRMASS ALOFT OVERNIGHT.  SUFFICIENT SATURATION CONTINUES FOR BROKEN
STRATO CU BEHIND THE FRONT GIVEN TURBULENT MIXING OF THE WEST TO
NORTHWEST LOW LEVEL FLOW. CONSENSUS GUIDANCE LOWS NEAR 55 W TO NEAR
61 E ARE FAVORED.

THU...EXPECT RIDGING ALOFT WITH LIGHT SW SURFACE FLOW AND RELATIVELY
DRY STABLE AIR ABOVE 800 MB.  MOISTURE AND DIURNAL INSTABILITY
SHOULD YIELD PARTLY OR VARIABLY CLOUDY STRATO CU.  GUIDANCE SUPPORTS
LOWER TO MID 70S MAX TEMPERATURES.

THU NIGHT AND FRI...A DEEP UPPER TROUGH APPROACHES THEN PASSES BY
18Z FRI.  THIS PUSHES A SIGNIFICANT COLD FRONT ACROSS THE SOUTHERN
APPALACHIANS BY 12Z FRI AND RAPIDLY ACROSS THE CWA BY NOON.  A 50-60
KNOT JET AT 850 MB AND MAX DIVERGENCE ALOFT SHOULD SUPPLY AMPLE
DYNAMICAL LIFT FOR WIDESPREAD RAIN AND EMBEDDED THUNDERSTORMS
POSSIBLY FOCUSED IN A SQUALL LINE WITH PRIME TIME FOR CROSSING THE
RAH CWA BETWEEN 6 AM AND NOON. POPS IN THE HIGH CHANCE CATEGORY THU
NIGHT AND LIKELY CATEGORY FRI MORNING ARE FAVORED WITH MINS IN THE
MID 50S WITH MAXS HOLDING TO MID 60S.

FRI NIGHT AND SAT...COOL AND DRY WITH MODERATELY FAST WESTERLY FLOW
AND SUBSIDENCE ALOFT.  EXPECT MOSTLY CLEAR SKIES AND MINS DIPPING TO
MID 40S FOLLOWED BY HIGHS MID 60S TO NEAR 70.
&&

.LONG TERM (SUNDAY THROUGH WEDNESDAY)...
ZONAL FLOW ALOFT COMBINED WITH WEAK HIGH PRESSURE AT THE SURFACE WILL
KEEP SUNDAY AND MONDAY DRY AND SEASONABLY COOL. FLAT FLOW WILL
ADVECT MID AND HIGH LEVEL CLOUDINESS KEEPING SKIES VARIABLY CLOUDY.
SHORTWAVE TROUGH THAT SWINGS THROUGH THE PLAINS MONDAY AND TUESDAY
DAMPENS OUT AS IT LIFTS NORTH OF THE AREA. UPPER LEVEL SUPPORT AND
SURFACE WARM FRONT REMAIN NORTH AND WEST OF AREA. BUT SHOULD SEE
INCREASING CLOUD COVERAGE...ESPECIALLY OVER WESTERN AND NORTHWEST
CWA. IN THE MEANTIME...RISING HEIGHTS IN RESPONSE TO WESTERN US
TROUGHINESS AND SURFACE RETURN FLOW WILL BRING MODERATING
TEMPERATURES WITH TEMPERATURES 2-3 DEGREES ABOVE NORMAL BY MID
WEEK.
&&

.AVIATION...
TSTMS SHOULD DEVELOP ACROSS THE AREA THIS AFTERNOON...AND WILL
LINGER INTO THE EVENING AT EASTERN SITES...BRINGING CIGS AND VSBYS
WELL INTO THE MVFR RANGE AND PERHAPS INTO IFR. CIGS SHOULD REMAIN IN
PLACE THROUGH THE NIGHT...BUT WITH WESTERLY WINDS AND A DOWNSLOPE
COMPONENT...CIGS SHOULD LIFT INITIALLY OVERNIGHT AT THE WESTERNMOST
TAF SITES. HOWEVER...WITH RESIDUAL BL MOISTURE...IFR STRATUS SHOULD
DEVELOP. WITH SUFFICIENT MOISTURE IN PLACE...EXPECT SCATTERED FOG
DEVELOPMENT...BUT WINDS SHOULD STAY STRONG ENOUGH FOR VSBYS TO
REMAIN MVFR. A STRATOCU DECK DEVELOPS THURSDAY MORNING AS THE
STRATUS AND FOG BOTH LIFT...AND WILL LINGER INTO THE EARLY
AFTERNOON.
&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
&&

SHORT TERM...RFG
LONG TERM...LOCKLEAR
AVIATION...TP

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RALEIGH NC
445 AM EDT WED OCT 13 2004

NCZ007>011-021>028-038>043-073>078-083>086-088-089-140825-
ALAMANCE NC-ANSON NC-CHATHAM NC-CUMBERLAND NC-DAVIDSON NC-DURHAM NC-
EDGECOMBE NC-FORSYTH NC-FRANKLIN NC-GRANVILLE NC-GUILFORD NC-
HALIFAX NC-HARNETT NC-HOKE NC-JOHNSTON NC-LEE NC-MONTGOMERY NC-
MOORE NC-NASH NC-ORANGE NC-PERSON NC-RANDOLPH NC-RICHMOND NC-
SAMPSON NC-SCOTLAND NC-STANLY NC-VANCE NC-WAKE NC-WARREN NC-WAYNE NC-
WILSON NC-
INCLUDING THE CITIES OF...ALBEMARLE...ASHEBORO...BURLINGTON...
CHAPEL HILL...CLINTON...DURHAM...FAYETTEVILLE...GOLDSBORO...
GREENSBORO...HENDERSON...LAURINBURG...LEXINGTON...LILLINGTON...
LOUISBURG...MOUNT OLIVE...NASHVILLE...OXFORD...PITTSBORO...RAEFORD...
RALEIGH...ROANOKE RAPIDS...ROCKINGHAM...ROCKY MOUNT...ROXBORO...
SANFORD...SMITHFIELD...SOUTHERN PINES...TARBORO...TROY...WADESBORO...
WARRENTON...WILSON AND WINSTON-SALEM
445 AM EDT WED OCT 13 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT...

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER CENTRAL NORTH
CAROLINA...MAINLY THIS AFTERNOON INTO THE EARLY EVENING. A LOW
PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE PIEDMONT THIS
AFTERNOON AND LIFT NORTHEAST INTO SOUTHEASTERN VIRGINIA. THIS...IN
COMBINATION WITH MOIST...UNSTABLE AIR OVER THE REGION AND STRONG
UPPER LEVEL WINDS WILL PRODUCE THE POTENTIAL FOR A FEW SEVERE
THUNDERSTORMS...MAINLY THIS AFTERNOON INTO THE EARLY EVENING. THE
PRIMARY THREAT WILL BE DAMAGING WINDS. AN ISOLATED TORNADO IS
POSSIBLE.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...
THURSDAY...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

THURSDAY NIGHT AND FRIDAY...
ANOTHER ROUND OF SHOWERS AND SCATTERED THUNDERSTORMS WILL DEVELOP
OVER THE AREA THURSDAY NIGHT THROUGH FRIDAY IN RESPONSE TO A STRONG
UPPER LEVEL LOW PRESSURE THAT WILL CROSS THE AREA FRIDAY. THERE IS THE
POTENTIAL THAT A FEW STORMS COULD COULD APPROACH SEVERE DURING
FRIDAY.

SATURDAY THROUGH TUESDAY...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER NETWORK ACTIVATION MAY BE REQUIRED THIS AFTERNOON INTO THE
EARLY EVENING...2PM TIL ABOUT 8 PM.

EMERGENCY MANAGEMENT OFFICIALS AND LOCAL STORM SPOTTER GROUPS
SHOULD CLOSELY MONITOR THE LATEST FORECASTS AND STATEMENTS FROM
THE NATIONAL WEATHER SERVICE.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

RA

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
557 PM EDT WED OCT 13 2004

NCZ041-132300-

WAKE NC-
557 PM EDT WED OCT 13 2004

...THUNDERSTORMS WITH HEAVY RAIN WILL MOVE ACROSS WAKE COUNTY
THROUGH 700 PM EDT...

AT 557 PM EDT...DOPPLER RADAR INDICATED THUNDERSTORMS WITH HEAVY
RAIN EXTENDING FROM DOWNTOWN RALEIGH SOUTHWEST TO HOLLY SPRINGS. THE
STORMS WERE MOVING NORTHEAST AT 10 MPH.

SOME LOCATIONS AFFECTED BY THESE STORMS
INCLUDE...RALEIGH...KNIGHTDALE...AND...FALLS LAKE...ROLESVILLE.

VERY HEAVY RAIN WITH RAINFALL AMOUNTS EXCEEDING ONE INCH DURING THE
NEXT HOUR CAN BE EXPECTED IN THESE AREAS. MOTORISTS SHOULD DRIVE WITH
CAUTION TO AVOID HYDROPLANING. MINOR FLOODING OF LOW LYING AREAS...
CREEKS...STEAMS AND SOME ROADS CAN BE EXPECTED.

WSS