Severe Thunderstorm Warning 191, NWS Raleigh, NC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
215 PM EDT MON JUL 20 2009

.SYNOPSIS...
THE COMBINATION OF A STATIONARY FRONT SITTING OVER EASTERN NORTH
CAROLINA... AND UPPER LEVEL LOW PRESSURE SITTING JUST TO OUR WEST...
WILL KEEP HUMID AND UNSETTLED WEATHER OVER THE REGION INTO MIDWEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 215 PM MONDAY...

THE UPPER JET MAXIMA IS LOCATED OVER THE BLUE RIDGE THIS AFTERNOON
WITH STREAKY CONVECTION BEGINNING TO FIRE IN THE DESTABILIZED
AIRMASS IN THE WESTERN CWFA. MEANWHILE...ONGOING CONVECTION OVER THE
EASTERN CWFA IS BECOMING MORE WIDESPREAD. THE SLOW EASTWARD
TRANSLATION OF THE UPPER SUPPORT IS TENDING TO ANCHOR THE
CONVECTIONS INITIATION POINT...CREATING TRAINING ECHOES WHICH WILL
CREATE A THREAT FOR FLOODING IF ONE OF THE CONVECTIVE STREAKS LINES
UP OVER AN URBAN SETTING.

ONGOING LIKELY POPS THROUGH EVENING LOOK ON TRACK...WITH A
DIMINISHING TREND OVERNIGHT WITH LOSS OF INSOLATION. UPPER TROF
CONTINUES TO PROVIDE SOME DYNAMIC SUPPORT INTO THE NORTHEASTERN
CORNER OF THE CWFA THROUGH SUNRISE...SO WILL HANG ON TO CHANCE POPS
IN THAT AREA ALL NIGHT. ONGOING FORECAST MINS REMAIN IN LINE WITH
LATEST MOS NUMBERS... MID-UPPER 60S...SO SEE NO REASON TO MAKE
SIGNIFICANT CHANGES.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 215 PM MONDAY...

THE UPPER TROUGH WILL SWING THROUGH THE AREA FROM SOUTHWEST TO
NORTHEAST ON TUESDAY. CONVECTION WILL BE SCATTERED AHEAD OF THE TROF
IN THE NORTHEAST...DIMINISHING BACK TO THE WEST ACCORDINGLY. SKIES
SHOULD BE AT LEAST PARTLY SUNNY IN THE WEST DUE TO MIXING AND
SUBSIDENCE BEHIND THE TROF...WITH LINGERING CLOUDINESS IN THE EAST.
AN AFTERNOON CU FIELD WILL DEVELOP DURING IN THE EARLY AFTERNOON AS
TEMPS REACH THE MID AND UPPER 80S.

TUE NIGHT...THE UPPER TROF WILL BE NORTH OF THE AREA WITH LARGER
SCALE LIFT WANING. WILL HAVE ONLY LINGERING SLIGHT CHANCES FOR
PRECIP OVERNIGHT. WITH NO CHANGE TO AIRMASS...EXPECT LOWS TO FOLLOW
A SIMILAR TREND...IN THE MID TO UPPER 60S.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...

WEAK SOUTH FLOW AT THE SURFACE IN GENERAL DURING THE PERIOD. FLOW
BECOMES NEAR ZERO FRIDAY AS PRESSURE GRADIENT DROPS. SOUTH TO
SOUTHWEST WINDS BEGIN TO PICK UP SATURDAY AHEAD OF LOW PRESSURE IN
THE WESTERN GREAT LAKES...THOUGH THE GFS IS TOO FAR SOUTH AND DEEP
WITH THIS LOW. DECENT UPPER TROUGH WEST OF THE MISSISSIPPI BY
SATURDAY NIGHT WITH WITH THE ECMWF BRINGING PRECIPITATION IN DURING
THIS TIME AND EXTENDING IT INTO SUNDAY. SLOWER TIMING IS ALMOST
ALWAYS BEST (CANADIAN EVEN SLOWER) SO WILL DELAY ANY ENHANCEMENT OF
RAIN CHANCES TO SUNDAY. SURFACE FLOW CONTINUES SOUTH INTO MONDAY
WITH RAIN CHANCES NEAR TO A BIT BELOW CLIMATOLOGY THEN. UNTIL SUNDAY
RAIN CHANCES WILL BE BEST IN THE AFTERNOON AND IN THE EAST... WHERE
MOISTURE AND INSTABILITY BEST. FRIDAY COULD POTENTIALLY BE THE
DRIEST DAY AS A WHOLE OVER CENTRAL NORTH CAROLINA DUE TO THE WEAK
WIND FIELD LIMITING CONVERGENCE.

TEMPERATURES NOT FAR FROM CLIMATOLOGY WITH MORNING LOWS 66 TO 72 AND
HIGH TEMPERATURES 86 TO 92.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 130 PM MONDAY...

SURFACE FRONT STRETCHES ACROSS EASTERN NORTH CAROLINA FROM RDU
SOUTHWEST TO NEAR ROCKINGHAM EARLY THIS AFTERNOON. TSRA ARE
DEVELOPING IN THE WARM SECTOR EAST OF THE FRONT AND ARE EXPECTED TO
BECOME QUITE NUMEROUS DUE TO THE EASTWARD TRANSLATION OF AN UPPER
JET STREAK ON THE EAST SIDE OF THE DEEP UPPER TROF OVER THE OHIO
VALLEY. AS SUCH...WILL HAVE A PERIOD OF THUNDER IN THE EASTERN
TAFS...RDU/FAY/RWI...UNTIL LOSS OF INSOLATION AROUND 02Z. IN THE
WEST...THUNDER IS STILL A POSSIBILITY...BUT COVERAGE SHOULD BE A BIT
MORE SCATTERED...AND WILL HANDLE WITH VCTS IN THE TAFS. THE UPPER
TROF WILL GRADUALLY LIFT OUT OVERNIGHT...WITH CHANCES FOR CONVECTION
COVERAGE DIMINISHING EARLY TONIGHT...THEN ENDING IN THE EAST AROUND
MIDNIGHT.

THE MOISTER AIRMASS IN THE EAST WILL BE CONDUCIVE TO SOME MVFR...
PERHAPS IFR...FOG IN THE EAST IN THE USUAL 09-12Z TIME FRAME. IF
CLOUD COVERAGE DISSIPATES OVERNIGHT...COULD SEE BRIEF IFR CEILINGS
IN THE EAST DURING THE USUAL 09-12Z TIME FRAME AS WELL. SUBSIDENCE
AND MIXING SHOULD PRODUCE PARTLY CLOUDY SKIES TOMORROW MORNING...
WITH A VFR CU FIELD DEVELOPING AS TEMPS REACH THE MID 80S AROUND
NOONTIME.

LOOKING BEYOND TONIGHT: SCATTERED STORMS ARE POSSIBLE...MAINLY
EAST...TUESDAY AFTERNOON/EVENING ASSOCIATED WITH THE UPPER LOW
LIFTING NORTHEAST AND OUT OF NE CWA. THEN BEHIND THIS DISTURBANCE WE
SHOULD SEE CONVECTIVE COVERAGE REDUCED TO ISOLATED TO SCATTERED
THROUGH THE REST OF THE WORK WEEK. MVFR VSBYS IN FOG ARE POSSIBLE
EACH MORNING WEDNESDAY THROUGH SATURDAY.

&&

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

&&

SYNOPSIS...HARTFIELD
NEAR TERM...MLM
SHORT TERM...MLM
LONG TERM...BSD
AVIATION...MLM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RALEIGH NC
1000 AM EDT MON JUL 20 2009

NCZ007>011-021>028-038>043-073>078-083>086-088-089-210900-
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-
1000 AM EDT MON JUL 20 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP THIS AFTERNOON AND CONTINUE INTO THE EVENING. A FEW OF THESE
STORMS MAY BECOME SEVERE. DAMAGING WIND GUSTS EXCEEDING 50 MPH AND
HAIL LARGER THAN 3/4 INCH ARE POSSIBLE.

IN ADDITION...THERE IS A CHANCE THAT SEVERAL STORMS COULD PASS OVER
SOME LOCATIONS WITHIN A PERIOD OF 2 TO 3 HOURS...PRODUCING LOCALIZED
FLASH FLOODING...ESPECIALLY IN URBAN AREAS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
SKYWARN SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON INTO THE
EVENING HOURS. SPOTTERS SHOULD STAY TUNED AND REPORT ANY SEVERE
WEATHER.

13

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
249 PM EDT MON JUL 20 2009

NCZ075-201945-
MOORE-
249 PM EDT MON JUL 20 2009

...A STRONG THUNDERSTORM WILL MOVE ACROSS MOORE COUNTY THROUGH 345 PM
EDT...

AT 249 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 6 MILES
WEST OF ROBBINS...OR ABOUT 12 MILES EAST OF TROY...MOVING NORTHEAST
AT 10 MPH.

SOME LOCATIONS AFFECTED BY THIS STORM INCLUDE...ROBBINS...GLENDON...
AND...HIGHFALLS.

GUSTY WINDS OF 30 TO 40 MPH...SMALL HAIL AND DANGEROUS
CLOUD-TO-GROUND LIGHTNING CAN BE EXPECTED WITH THESE THUNDERSTORMS.

14

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
303 PM EDT MON JUL 20 2009

NCZ010-011-026-027-202000-
FRANKLIN-HALIFAX-NASH-WARREN-
303 PM EDT MON JUL 20 2009

...A STRONG THUNDERSTORM WILL MOVE ACROSS WARREN...HALIFAX...FRANKLIN
AND NASH COUNTIES THROUGH 400 PM EDT...

AT 258 PM EDT...DOPPLER RADAR INDICATED STRONG THUNDERSTORMS
STRETCHING ACROSS THE NORTHEAST COASTAL PLAIN FROM JUST NORTH OF
ROCKY MOUNT NORTH ACROSS CASTALIA...CENTERVILLE...ARCOLA AND
WARRENTON. THESE STORMS WERE MOVING SLOWLY NORTHEAST AROUND 10 MPH
AND WILL REACH LITTLETON AROUND 315 PM...AND ROANOKE RAPIDS AROUND
330 PM.

RADAR ESTIMATES THAT UP TO 2 INCHES OF RAIN HAS FALLEN DURING THE
PAST HOUR AND AN ADDITIONAL 1 TO 2 INCHES IS POSSIBLE THROUGH 400
PM. MINOR FLOODING WILL BE POSSIBLE ON SMALLER STREAMS AND IN POORLY
DRAINED AREAS.

GUSTY WINDS OF 30 TO 40 MPH...AND DANGEROUS CLOUD-TO-GROUND
LIGHTNING CAN BE EXPECTED WITH THESE STORMS. THE STORMS WILL REACH
LAKE GASTON AND ROANOKE RAPIDS LAKE BY 315 PM. BOATERS ON THESE
LAKES SHOULD SEEK HARBOR BEFORE THESE STORMS ARRIVE.

13

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
359 PM EDT MON JUL 20 2009

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

0345 PM     HAIL             1 SSW GLENDON           35.46N 79.54W
07/20/2009  E1.00 INCH       MOORE              NC   LAW ENFORCEMENT

            NICKLE TO QUARTER SIZE HAIL REPORTED AT THE HIGH FIELD
            FIRE DEPARTMENT

&&

PAGANO

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
400 PM EDT MON JUL 20 2009

NCZ024-025-040>042-076-202100-
CHATHAM-DURHAM-JOHNSTON-LEE-ORANGE-WAKE-
400 PM EDT MON JUL 20 2009

...THUNDERSTORMS WITH HEAVY RAIN...STRONG GUSTY WINDS AND HAIL WILL
CONTINUE TO DEVELOP ACROSS THE TRIANGLE THROUGH 500 PM EDT...

AT 355 PM EDT...DOPPLER RADAR INDICATED NUMEROUS THUNDERSTORMS WITH
VERY HEAVY RAIN OVER THE TRIANGLE...MOVING NORTHEAST AT 10 MPH.

THE STRONGEST THUNDERSTORMS WILL MOVE NEAR NEW HOPE...FALLS
LAKE...WAKE FOREST...DURHAM...FEARRINGTON AND PITTSBORO..
AND...ROLESVILLE...PURNELL. GUSTY WINDS OF 30 TO 45 MPH...VERY HEAVY
RAIN AND DANGEROUS CLOUD-TO-GROUND LIGHTNING CAN BE EXPECTED WITH
THESE STORMS.

THE HEAVY RAIN WILL LIKELY MAKE TRAVEL DIFFICULT DURING THE EVENING
RUSH HOUR.

BLAES