Severe Thunderstorm Warning 224, NWS Nashville, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1253 PM CDT SAT JUN 26 2010

.UPDATE...26/18Z AVIATION FORECAST

&&

.AVIATION...
LOOK FOR SCATTERED TSTMS THIS AFTERNOON ACROSS THE MID STATE AS
DIURNAL HEATING CRANKS UP. STORMS WILL BE MOVING EAST AT ABOUT 10
15 MPH AND PRODUCE WET MICROBURSTS CONDITIONS WITH BRIEF HEAVY
RAINFALL AND REDUCED VSBYS FOR A SHORT PERIOD OF TIME. OUTSIDE OF
STORMS GENERALLY VFR CONDITIONS BUT MVFR LATE TONIGHT DUE TO FOG.

BOYD

&&

.PREV DISCUSSION... /ISSUED 925 AM CDT SAT JUN 26 2010/

UPDATE...GRIDS AND ZONES HAVE ALREADY BEEN UPDATED TO MENTION
THUNDER POPS THROUGHOUT THE DAY. SCATTERED CONVECTION ALREADY FIRED
UP OVER OUR NORTHWEST COUNTIES...AND A CELL HAS DEVELOPED OVER
NASHVILLE. DIFFUSE FRONTAL ZONE AND LEFTOVER BOUNDARIES WILL
CONTRIBUTE TO CONTINUED CONVECTIVE DEVELOPMENT AS THE ATMOSPHERE
DESTABILIZES TODAY. POPS WILL RANGE FROM AROUND 10 NORTHEAST TO 40
SOUTHWEST. ALSO ADJUSTED TEMPS UP A DEGREE OR SO...MORNING
SOUNDING AND UPSTREAM COMPARISONS INDICATE MANY AREAS WILL TOUCH
95 TODAY...BUT THAT WILL DEPEND ON EXACTLY WHERE THUNDERSTORMS
OCCUR.

WE ARE NOT UNDER AN SPC SLIGHT RISK FOR SEVERE WX. HOWEVER...GOOD
INSTABILITY WITH WEAK SHEAR WILL PROMOTE ISOLATED DOWBURST WIND
EVENTS. A FEW SEVERE WARNINGS WILL PROBABLY BE ISSUED.

PREV DISCUSSION... /ISSUED 545 AM CDT SAT JUN 26 2010/

AVIATION...BNA/CSV...AFTER TWO DAYS OF SCATTERED CONVECTION,
WE'RE LOOKING AT A DRIER AIR MASS TODAY. AT MOST, WE'LL SEE
ISOLATED AFTERNOON STORMS ACROSS MIDDLE TENNESSEE, SO WILL HANDLE
THIS WITH CB REMARKS IN THE TAF'S. OTHERWISE, LOOK FOR VFR WX W/
GENERALLY LIGHT SW WINDS. PERHAPS SOME LIGHT FOG LATE TONIGHT AT
CSV.

PREV DISCUSSION... /ISSUED 306 AM CDT SAT JUN 26 2010/

ISOLATED TO SCATTERED CONVECTION TODAY UNDER LIGHT SLY FLOW AT
THE SFC WITH A FRONTAL SYSTEM WELL TO THE NORTH OVER THE GREAT
LAKES AND NRN PLAINS. DIRUNALLY MODULATED CONVECTION WILL CONTINUE
THROUGH THE WEEKEND AS THE FRONT WORKS IT WAY SWD INTO THE OH/TN
VALLEYS.

FRONT PUSHES SWD THROUGH THE AREA LATE MON. BUT NOT A LOT OF COOL
AIR BEHIND IT...MAINLY DRIER AIR. THE INITIAL H5 SHORTWAVE MERELY
PUSHES THE FRONT FURTHER SWD. HOWEVER...HIGHS WILL STILL BE IN THE
90S IN THE MON-WED PERIOD. HAVE TO WAIT A DAY OR TWO UNTIL WED NGT
WHEN THE UPPER TROUGH DEEPENS SGFNTLY OVER ERN CANADA AND TURNS
UPPER FLOW MORE NLY. THIS WILL BRING COOLER AIR AND DROP DAYTIME
HIGHS INTO THE MID 80S.

MAIN EFFECT OF THIS SCENARIO IS 3 FOLD: A) REDUCE THE DAYS OF
ABOVE NORMAL TEMPS B) REDUCE THE HUMIDITY AND C) SGFNTLY DIMINISH
THE PROBABILITY OF RAINFALL.

CPC PROGS CONTINUE TO INDICATE ABOVE NORMAL TEMPS IN THE 6-10 AND
8-14 DAY PERIODS. BUT THEN...WE'VE BEEN ABOVE 90 DEGREES FOR 14
OUT OF THE LAST 15 DAYS. SO I GUESS BEING 1-2 DEGREES ABOVE NORMAL
IS BETTER THAN BEING 7-8 DEGREES ABOVE NORMAL.

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

01

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
934 AM CDT SAT JUN 26 2010

TNZ005>011-022>034-056>066-075-077>080-093>095-271445-
STEWART-MONTGOMERY-ROBERTSON-SUMNER-MACON-CLAY-PICKETT-BENTON-
HOUSTON-HUMPHREYS-DICKSON-CHEATHAM-DAVIDSON-WILSON-TROUSDALE-
SMITH-JACKSON-PUTNAM-OVERTON-FENTRESS-PERRY-HICKMAN-LEWIS-
WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-CANNON-DE KALB-WHITE-
CUMBERLAND-BEDFORD-COFFEE-WARREN-GRUNDY-VAN BUREN-WAYNE-LAWRENCE-
GILES-
934 AM CDT SAT JUN 26 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT

HOT AND HUMID WEATHER...ALONG WITH WEAK SURFACE BOUNDARIES...WILL
HELP PRODUCE SCATTERED THUNDERSTORMS. A FEW OF THE STORMS COULD BE
STRONG TO BRIEFLY SEVERE THIS AFTERNOON AND EVENING. THE MAIN SEVERE
HAZARD WILL BE LOCALIZED DAMAGING WIND GUSTS. OTHERWISE...THE
SLOW MOVING STORMS WILL CONTAIN HEAVY RAINFALL AND FREQUENT
LIGHTNING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

STRONG AND ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE AGAIN
SUNDAY AND MONDAY. WARM AND HUMID AIR WILL BE OVER THE
REGION...AND A COLD WILL BE APPROACHING.

.SPOTTER INFORMATION STATEMENT...

EVEN THOUGH ANY SEVERE THUNDERSTORMS ARE EXPECTED TO BE BRIEF AND
ISOLATED, SPOTTERS ARE ENCOURAGED TO CLOSELY MONITOR WEATHER
CONDITIONS AND BE PREPARED TO CALL IN ANYTHING REACHING REPORTING
CRITERIA.

SPOTTER THUNDERSTORM REPORTING CRITERIA...
TORNADO
FUNNEL CLOUD
FLOODING
HAIL >= 1/2 INCH
WINDS > 50 MPH (MEASURED)
STRUCTURAL DAMAGE
TREES OR POWER LINES DOWN

13

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
1245 PM CDT SAT JUN 26 2010

TNZ027-059-261830-
DAVIDSON-WILLIAMSON-
1245 PM CDT SAT JUN 26 2010

...SIGNIFICANT WEATHER ADVISORY FOR DAVIDSON AND WILLIAMSON
COUNTIES...

AT 1238 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM NEAR BELLE MEADE...OR 8 MILES SOUTHWEST OF
DOWNTOWN NASHVILLE...MOVING EAST AT 10 MPH.

WINDS AROUND 40 MPH ARE EXPECTED WITH THIS STORM.

BOYD