Special Weather Statement, NWS Nashville, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1126 PM CDT FRI AUG 16 2013

.UPDATE...FOR 06Z AVIATION FORECAST

&&

.AVIATION...
ISOLATED PIN-HEAD SHOWERS HAVE BEEN WORKING SLOWLY TOWARD THE
NORTHWEST ACROSS MIDDLE TENNESSEE. WATER VAPOR SHOWING A TWIST IN
THE CLOUDS AT LATE EVENING OVER THE BOOTHEEL OF MISSOURI NEAR LOW
CENTER WITH INVERTED SURFACE TROUGH AXIS RUNNING UP ALONG THE
TENNESSEE RIVER INTO FAR WESTERN KENTUCKY. AIR MASS HAS
DESTABLIZED THROUGH THE MID-LEVELS THIS EVENING HELPING TO
MAINTAIN SHOWER ACTIVITY AFTER SUNDOWN. EXPECT THIS WILL BE THE
CASE THROUGH THE OVERNIGHT WITH WESTERN AREAS BEING AFFECTED THE
MOST. WITH DIURNAL HEATING ON SATURDAY EXPECT TO SEE SHOWERS AND
ISOLATED THUNDERSTORM COVERAGE INCREASE DURING THE DAY.

WILL KEEP VICINITY SHOWERS GOING THROUGH THE OVERNIGHT HOURS AND
DURING THE DAY ON SATURDAY. COULD SEE LATE NIGHT MVFR FOG DEVELOP
AT TERMINALS.

BOYD
&&

.PREV DISCUSSION... /ISSUED 827 PM CDT FRI AUG 16 2013/

UPDATE...

RADAR THIS EVENING SHOWS ISOLATED SHOWERS CONTINUE ALONG AND NORTH
OF A LINE FROM CAMDEN TO MCMINNVILLE. GUIDANCE INDICATES AS UPPER
LEVEL LOW TROUGH CONTINUES TO STRENGTHEN OVERNIGHT...ISOLATED TO
WIDELY SCATTERED SHOWERS WILL REMAIN POSSIBLE. WILL MAINTAIN
INHERITED LOW POPS THROUGH THE NIGHT WITH HIGHEST POPS IN WESTERN
ZONES CLOSER TO UPPER LOW CENTER. OTHERWISE...00Z OHX SOUNDING
SHOWS A CONTINUED MOISTENING TREND WITH A PWAT NOW UP TO 1.35
INCHES. SURFACE DEWPOINTS ALSO MUCH HIGHER THAN THIS TIME
YESTERDAY IN THE MID TO UPPER 60S...AND MADE ADJUSTMENTS TO GRIDS
BASED ON CURRENT OBS. WITH WIDESPREAD CLOUD COVER AND PLENTIFUL
LOW LEVEL MOISTURE...LOW TEMPS TONIGHT LOOK A TAD ON THE COOL SIDE
AND NUDGED THEM UP SLIGHTLY. CLOUD COVER SHOULD ALSO KEEP FOG
SPARSE DESPITE THE LOW DEWPOINT DEPRESSIONS. OTHER THAN
THAT...MADE SOME MINOR TWEAKS TO DEWPOINTS BUT NO OTHER CHANGES.

SHAMBURGER

PREV DISCUSSION... /ISSUED 651 PM CDT FRI AUG 16 2013/

UPDATE...FOR 00Z AVIATION FORECAST

AVIATION...
UPPER TROUGH DEPICTED QUITE WELL BY THERMAL FIELD EXTENDING DOWN
THROUGH THE OZARKS WITH 65 KNOT UPPER JET RUNNING FROM LOWER MISSISSIPPI
VALLEY UP ALONG THE OHIO RIVER. GOOD TWIST IN WATER VAPOR OVER CENTRAL
ARKANSAS. AT THE SURFACE AN INVERTED TROUGH EXTENDS FROM LOWER MISSISSIPPI
VALLEY ACROSS THE TENNESSEE VALLEY. ALL IN ALL LOOKING FOR UNSETTLED
WEATHER HERE IN THE MID STATE NEXT 24 HOURS AND BEYOND AS PATTERN
WILL CHANGE LITTLE. SOME LATE NIGHT MVFR CONDITIONS DUE TO FOG CAN
BE EXPECTED. LOOK FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
AS WE GO THROUGH THE WEEKEND.

BOYD

PREV DISCUSSION... /ISSUED 343 PM CDT FRI AUG 16 2013/

DISCUSSION...
RADAR SHOWING LIGHT SHOWER DEVELOPMENT ACROSS MAINLY WESTERN
PORTIONS OF THE MID STATE. THIS IS IN RESPONSE TO A DEVELOPING UPPER
TROUGH. THE TROUGH AXIS IS JUST WEST OF THE MS RIVER WITH DESCENT
PVA LOCATED JUST EAST OF THAT AXIS. FURTHERMORE...A WEAK SFC
BOUNDARY STRETCHES FROM NRN MS THROUGH THE MID STATE.

FOGWISE...IT DOES LOOK AS THOUGH REDUCED VSBYS ARE POSSIBLE THE NEXT
2 OVERNIGHTS. HOWEVER...I EXPECT VALUES OF LESS THAN 1SM FOR ISOL
AREAS ONLY. THUS...WILL KEEP FOG OUT OF THE FORECAST FOR NOW.

OTHERWISE...FOR THE UPCOMING FORECAST...THE AFOREMENTIONED UPPER
TROUGH WILL CONTINUE TO AMPLIFY AND WILL ACTUALLY CUT OFF ON
SATURDAY. THUS...MOISTURE WILL CONTINUE TO INCREASE BUT OVERALL
DYNAMICS WITH THE FEATURE ARE GENERALLY WEAK. SO...THIS ALL EQUATES
TO A CONTINUING CHANCE OF SHOWERS AND PERHAPS A TSTM OR TWO. CAPE
VALUES REALLY DO NOT RECOVER UNTIL SUNDAY. RAIN AMOUNTS WILL BE ON
THE LIGHT SIDE. THE FORECAST FOR THE NEAR TERM WILL INCLUDE
GENERALLY 20-40 PERCENT CHANCES OF SHOWERS.

FOR THE NEAR TERM TEMPS...VALUES WILL REMAIN BELOW NORMAL. MIN TEMPS
WILL INCREASE GRADUALLY EACH DAY AS MORE IN THE WAY OF HUMIDITY
RETURNS.

IN THE EXT FCST...THE CLOSED UPPER LOW WILL LIFT OFF TO THE
NORTHEAST BY MONDAY. UPPER RIDGING WILL BUILD ACROSS THE
SOUTHWESTERN U.S. AND WE WILL ALSO SEE THE REEMERGENCE OF THE
BERMUDA HIGH. THIS WILL LEAVE TN IS A SOMEWHAT WEAKER AREA OF HIGH
PRESSURE ALOFT. THIS EQUATES TO A MORE TYPICAL AUGUST PATTERN. WILL
THEREFORE INCLUDE 20-30 PERCENT CHANCES OF AFT AD EVE SHOWERS AND
TSTMS EACH DAY.

FOR THE EXT TEMPS...EARLY IN THE EXT WE WILL SEE NEAR NORMAL TEMPS.
BUT...BY THE END OF THE EXTENDED(THU AND FRI) TEMPS WILL CLIMB TO A
FEW DEGREES ABOVE NORMAL...LOWS NEAR 70 HIGHS LOWER 90S. VERSUS THE
MEX...NO MAJOR DEVIATIONS INCLUDED.

&&

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

01

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
536 AM CDT FRI AUG 16 2013

TNZ005>011-022>034-056>066-075-077>080-093>095-171045-
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-
536 AM CDT FRI AUG 16 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

19

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
119 AM CDT SAT AUG 17 2013

TNZ006>008-025>027-170700-
CHEATHAM-DAVIDSON-DICKSON-MONTGOMERY-ROBERTSON-SUMNER-
119 AM CDT SAT AUG 17 2013

...SIGNIFICANT WEATHER ADVISORY FOR CHEATHAM...DAVIDSON...DICKSON...
MONTGOMERY...ROBERTSON AND SUMNER COUNTIES...

AT 113 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A LINE OF SCATTERED THUNDERSTORMS...WITH HEAVY DOWNPOURS AND GUSTY
WINDS...ALONG A LINE EXTENDING FROM GOODLETTSVILLE TO ASHLAND CITY
TO 7 MILES NORTHWEST OF WHITE BLUFF TO DICKSON...MOVING NORTHEAST AT
15 MPH.

SOME LOCATIONS IN THE PATH INCLUDE JOELTON...RIDGETOP...SPRINGFIELD
MILLERSVILLE...CHARLOTTE...ASHLAND CITY...GOODLETTSVILLE...BEAMAN
PARK AND WHITES CREEK.

WIND GUSTS TO AROUND 30 MPH ARE EXPECTED WITH SOME OF THESE
STORMS...AND HEAVY DOWNPOURS WILL LIKELY CAUSE PONDING OF WATER IN LOW
LYING AREAS.

LAT...LON 3630 8665 3619 8705 3608 8742 3637 8753
      3657 8681

19

SPECIAL WEATHER STATEMENT...CORRECTED STORM MOTION
NATIONAL WEATHER SERVICE NASHVILLE TN
121 AM CDT SAT AUG 17 2013

TNZ006>008-025>027-170700-
CHEATHAM-DAVIDSON-DICKSON-MONTGOMERY-ROBERTSON-SUMNER-
121 AM CDT SAT AUG 17 2013

...SIGNIFICANT WEATHER ADVISORY FOR CHEATHAM...DAVIDSON...DICKSON...
MONTGOMERY...ROBERTSON AND SUMNER COUNTIES...

AT 113 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A LINE OF SCATTERED THUNDERSTORMS...WITH HEAVY DOWNPOURS AND GUSTY
WINDS...ALONG A LINE EXTENDING FROM GOODLETTSVILLE TO ASHLAND CITY
TO 7 MILES NORTHWEST OF WHITE BLUFF TO DICKSON...MOVING NORTHWEST AT
15 MPH.

SOME LOCATIONS IN THE PATH INCLUDE JOELTON...RIDGETOP...SPRINGFIELD
MILLERSVILLE...CHARLOTTE...ASHLAND CITY...GOODLETTSVILLE...BEAMAN
PARK AND WHITES CREEK.

WIND GUSTS TO AROUND 30 MPH ARE EXPECTED WITH SOME OF THESE
STORMS...AND HEAVY DOWNPOURS WILL LIKELY CAUSE PONDING OF WATER IN
LOW LYING AREAS.

LAT...LON 3630 8665 3619 8705 3608 8742 3637 8753
      3657 8681

19