Special Weather Statement, NWS Nashville, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1218 PM CDT THU MAR 15 2012

.UPDATE...

18Z TAF DISCUSSION.

&&

.AVIATION...

LATEST RADAR IMAGERY SHOWING SCATTERED SHRA/TSRA DEVELOPING ATTM
WITH COVERAGE EXPECTED TO INCREASE THROUGH THE AFTERNOON AS
SHORTWAVE OVER THE SOUTHERN PLAINS APPROACHES. HAVE ADDED VCTS TO
ALL AIRPORTS THROUGH 01Z WITH TEMPO TSRA DUE TO SCATTERED NATURE
OF CONVECTION. ACTIVITY TO DIMINISH THIS EVENING ALTHOUGH ALL
MODELS INDICATE REDEVELOPMENT OVERNIGHT AS SHORTWAVE PASSES OVER.
DESPITE PRECIP...CONDITIONS TO REMAIN VFR ALTHOUGH BRIEF MVFR IS
POSSIBLE IN THE HEAVIEST SHRA/TSRA.

&&

.PREV DISCUSSION... /ISSUED 1202 PM CDT THU MAR 15 2012/

UPDATE...
MO BOOTHEEL TSTM COMPLEX MOVG NE BUT BUILDING SOUTH INTO MORE
UNSTABLE AIR. OUTFLOW COULD PRODUCE ORGANIZED AREA OF STORMS IN
NW MID TN LATER THIS AFTN...W/LKLY POPS. ELSEWHERE HEATING WL
SUPPORT A SCATTERED PATTERN FURTHER SOUTH AND EAST. SOME SEVERE
TSTMS EXPECTED WITH LARGE HAIL.

PREV DISCUSSION... /ISSUED 626 AM CDT THU MAR 15 2012/

UPDATE...ADDED AVIATION SECTION FOR 12Z TAF'S.

AVIATION...CKV/BNA/CSV...EXPECT WARM, UNSTABLE AIR TO REMAIN IN
PLACE ACROSS MIDDLE TENNESSEE TODAY, WITH THUNDERSTORMS POSSIBLE.
MOST LIKELY TIME FOR CONVECTION IS DURING PEAK HEATING HOURS, AS
AN ALMOST SUMMER-LIKE PATTERN HAS SET UP ACROSS THE MID STATE.
OTHER THAN SOME BRIEF, LOW STRATUS AT CSV THIS MORNING, EXPECT
VFR WX THE NEXT 24 HRS OUTSIDE OF RAIN AREAS.

PREV DISCUSSION... /ISSUED 255 AM CDT THU MAR 15 2012/

SHORT TERM...LOOKING AT RADAR TRENDS OVER THE LAST 24 HOURS IT IS
EASY TO SEE THAT THE ATMOSPHERE ACROSS THE MID STATE HAS BECOME
INCREASINGLY MOIST AND UNSTABLE. EVEN EARLY THIS MORNING...A CLUSTER
OF THUNDERSTORMS WAS OBSERVED ALONG THE CUMBERLAND PLATEAU, ONE OF
WHICH DROPPED QUARTER-SIZE HAIL AT MONTEREY. ISOLATED SHOWERS
WERE OBSERVED BETWEEN NASHVILLE...MURFREESBORO AND WAYNESBORO.

CONVECTIVE PARAMETERS WILL BE ELEVATED TODAY THROUGH FRIDAY AND A
TREND TOWARD MORE WIDESPREAD THUNDERSTORM DEVELOPMENT IS EXPECTED.
MOS POPS CERTAINLY REFLECT THIS AND AVERAGE BETWEEN 50% AND 80% OVER
OUR FORECAST AREA. LOCAL ENHANCEMENT OF CONVECTION WILL LIKELY OCCUR
IN RESPONSE TO UPPER LEVEL SHORTWAVES RIPPLING NORTHEASTWARD OUT
OF NORTHEAST TEXAS AND THE LOWER MISSISSIPPI VALLEY.

THE STRONGEST SHORTWAVE THAT IS EXPECTED TO TRIGGER THE MOST
WIDESPREAD CONVECTION TODAY SHOWED UP NICELY ON SATELLITE WATER
VAPOR IMAGERY OVER NORTH-CENTRAL TEXAS AT 06Z. PATCH OF CLOUDS OVER
ARK-LA-TX AREA IS ALSO ASSOCIATED WITH THIS FEATURE. IF IT
CONTINUES MOVING AT ITS CURRENT SPEED IT SHOULD REACH MEMPHIS
AROUND NOON, AND CROSS MIDDLE TENNESSEE DURING THE HEAT OF THE
DAY. SINCE IT WILL BE CROSSING OUR AREA DURING THE AFTERNOON WE
SHOULD REAP MAXIMUM BENEFIT IN REGARD TO THUNDERSTORM COVERAGE.
WILL PROBABLY GO WITH LIKELY POPS OVER THE NORTHWESTERN TWO-THIRDS
OF OUR FORECAST AREA TODAY, WHERE 1000-500MB MEAN RH IS EXPECTED
TO INCREASE TO OVER 70%. THIS IS ALSO WHERE THE LOW LEVEL JET WILL
BE STRONGEST. THERE WILL CONTINUE TO BE A POSSIBILITY FOR ISOLATED
SEVERE STORMS TODAY, ESPECIALLY OVER NORTHWESTERN AREAS INVOF
STRONGEST LOW LEVEL JET.

BELIEVE SCATTERED THUNDERSTORMS WILL CONTINUE THURSDAY NIGHT, AND
BOTH GFS AND NAM SHOW EVEN DEEPER ATMOSPHERIC MOISTURE ACROSS OUR
AREA ON FRIDAY. 1000-500MB MEAN RH IS FORECAST TO BE 70% OR
GREATER OVER EASTERN MIDDLE TENNESSEE. THEREFORE, WILL GO WITH AN
AREA OF LIKELY POPS ON FRIDAY OVER THOSE AREAS.

BY FRIDAY NIGHT AND SATURDAY, DEEPEST ATMOSPHERIC MOISTURE PULLS
EAST AND CHANCE FOR RAIN DIMINISHES SOMEWHAT. GFS SUGGESTS THAT WE
WILL STILL BE VULNERABLE TO UPPER LEVEL SHORTWAVES MIGRATING IN FROM
THE SOUTHWEST (ESPECIALLY OVER OUR NORTHERN COUNTIES). CURRENTLY PLAN
TO GO WITH A 30% POP NORTH AND 20% SOUTH ON SATURDAY. FOLLOWING
SEVERAL DAYS WITH INCREASED CLOUDS, BELIEVE SATURDAY WILL BRING AN
INCREASE IN SUNSHINE AS THINGS DRY OUT A BIT. THUS, CONSIDERING THE
PACE OF WARMING WE'VE SEEN OVER THE LAST FEW DAYS, AM HESITANT TO
CUT TOO MUCH FROM MAV MOS NUMBERS.

STILL LOOKS LIKE UPPER TROUGH WILL DIG OVER THE WESTERN UNITED STATES
OVER THE WEEKEND AND EARLY NEXT WEEK, WITH RIDGE BUCKLING UP ACROSS
THE TENNESSEE VALLEY. MIGHT EVEN SEE SOME HIGH TEMPS IN THE MID 80S
SOMETIME DURING THE SUNDAY THROUGH TUESDAY PERIOD.

REACHING THE END OF ASTRONOMICAL WINTER NEXT TUESDAY, AT 1214 AM CDT,
WILL PROBABLY COME AND GO WITH HARDLY ANY NOTICE. MAX TEMPERATURES
WILL STILL BE AVERAGING SOME 20 DEGREES ABOVE NORMAL, AND SINCE THE
PREVIOUS 3 MONTHS WERE SO MILD ONE COULD JUSTIFIABLY ARGUE THAT IT
FELT LIKE WE NEVER REALLY HAD ANY "REAL WINTER" AT ALL. UNLIKE THE
UNUSUALLY COLD WEATHER ASSOCIATED WITH LA NINA DURING THE 2010-1011
WINTER, THE 2011-2012 LA NINA WINTER WILL END UP BEING MUCH MORE
TYPICAL, AND MUCH WARMER.

LONG TERM...GFS AND ECMWF SHOW 500MB CUT-OFF LOW DROPPING INTO
TEXAS BY THE MIDDLE OF NEXT WEEK AND MIGHT BE NEAR ENOUGH TO SWING
OUT A BAND OF DEEP MEAN RH, AND A BAND OF THUNDERSTORMS, INTO THE
MID STATE BY NEXT THURSDAY. MEANWHILE, WE WILL CONTINUE
UNSEASONABLY WARM AS WE REMAIN IN SOUTHERLY FLOW.

&&

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

SHAMBURGER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
514 AM CDT THU MAR 15 2012

TNZ005>011-022>034-056>066-075-077>080-093>095-161030-
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-
514 AM CDT THU MAR 15 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR NORTHWEST
MIDDLE TENNESSEE, INCLUDING THE NASHVILLE METROPOLITAN AREA.
SCATTERED THUNDERSTORMS ARE ONCE AGAIN EXPECTED TODAY AND TONIGHT,
AND A FEW OF THESE MAY BECOME SEVERE, WITH LARGE HAIL AND DAMAGING
STRAIGHT LINE WINDS THE PRIMARY THREATS. AREAS TO THE EAST AND
SOUTH OF NASHVILLE CAN STILL EXPECT A FEW STRONG STORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER CALL TO ACTION STATEMENT...

REPORTS FROM TRAINED WEATHER SPOTTERS MAY BE NEEDED.

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

ROSE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NASHVILLE TN
928 AM CDT THU MAR 15 2012

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

0428 PM     HAIL             10 S MCEWEN             35.96N 87.64W
03/14/2012  E1.25 INCH       HUMPHREYS          TN   POST OFFICE

&&

TJ

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
1216 PM CDT THU MAR 15 2012

TNZ025>027-057-059-151815-
CHEATHAM-DAVIDSON-DICKSON-HICKMAN-WILLIAMSON-
1216 PM CDT THU MAR 15 2012

...SIGNIFICANT WEATHER ADVISORY FOR CHEATHAM...DAVIDSON...DICKSON...
HICKMAN AND WILLIAMSON COUNTIES...

AT 1212 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 9 MILES SOUTH OF BURNS...OR 12 MILES SOUTHEAST
OF DICKSON...MOVING NORTHEAST AT 15 MPH.

THIS STORM WILL BE NEAR...
  FAIRVIEW BY 1245 PM CDT.
  PEGRAM BY 100 PM CDT.

PENNY SIZE HAIL...AND WINDS 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM.

LAT...LON 3597 8676 3584 8720 3585 8721 3583 8722
      3581 8731 3597 8741 3622 8691

SHAMBURGER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
1239 PM CDT THU MAR 15 2012

TNZ005-006-151845-
MONTGOMERY-STEWART-
1239 PM CDT THU MAR 15 2012

...SIGNIFICANT WEATHER ADVISORY FOR MONTGOMERY AND STEWART
COUNTIES...

AT 1236 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 8 MILES SOUTHWEST OF DOVER...MOVING NORTHEAST
AT 25 MPH.

THIS STORM WILL BE NEAR...
  DOVER BY 1255 PM CDT.

HALF INCH SIZE HAIL...AND WINDS 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM.

LAT...LON 3647 8731 3633 8786 3635 8794 3636 8800
      3645 8807 3646 8806 3664 8774 3665 8740

SHAMBURGER