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000
FXUS64 KOHX 171146
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
646 AM CDT FRI MAY 17 2013

.UPDATE...

12Z TAF DISCUSSION.

&&

.AVIATION...

RADAR IMAGERY INDICATES -SHRA HAVE BEGUN SPREADING OVER
CKV/BNA AND SOME -SHRA WILL APPROACH CSV IN A COUPLE HOURS. OFF
AND ON -SHRA CAN BE EXPECTED AT CKV/BNA THROUGH AROUND
18/06Z...WITH A FEW -TSRA ENTERING THE MIX LATER TODAY AND
ESPECIALLY BY EVENING AS UPPER LOW/TROUGH MOVES ACROSS. CIGS/VIS
WILL GRADUALLY LOWER FROM VFR TO MVFR THROUGH THE DAY AS LOW LEVEL
MOISTURE CONTINUES TO INCREASE...AND MAY FALL INTO IFR RANGE IN
HEAVIER -SHRA/-TSRA. LIGHT SOUTHEAST WINDS EXPECTED TODAY VEERING
TO SOUTHERLY/SOUTHWESTERLY OVERNIGHT AS UPPER LOW/TROUGH PASSES.

SHAMBURGER

&&

.PREV DISCUSSION... /ISSUED 323 AM CDT FRI MAY 17 2013/

DISCUSSION...

..SEVERAL CHANCES OF THUNDERSTORMS OVER THE NEXT WEEK WITH ISOLATED
SEVERE STORMS POSSIBLE AT TIMES...

UPPER LEVEL LOW SPINNING OVER NE ARKANSAS WILL BE OUR WEATHER MAKER
TODAY AND THROUGH THE WEEKEND BEFORE THE WORK WEEK IS GREETED WITH
UPPER-LEVEL RIDGING AND A SUMMER-LIKE WARM UP. FOR TODAY...THE UPPER
LOW WILL SLOWLY APPROACH AND PLACE MIDDLE TN UNDER GOOD UPPER-LEVEL
DIVERGENCE. WITH AMPLE MOISTURE STREAMING IN FROM THE SOUTH AHEAD OF
THIS...INSTABILITY SHOULD INCREASE PRETTY WELL TODAY DESPITE THE
AMPLE CLOUD COVER. DEEP LAYER WINDS ARE FAIRLY WEAK THOUGH AND WITH
MODERATELY HIGH PWATS...THINKING THAT WET MICROBURSTS COULD OCCUR
LATE THIS AFTERNOON AND EVENING ESPECIALLY SOUTH OF I-40 AND WEST OF
I-65. NEARING 00Z TONIGHT...SOUNDINGS OVER THE SWRN CWA HINT AT
INCREASED DIRECTIONAL AND SPEED SHEAR SO WILL HAVE TO WATCH THE
"SPIN-UP" POTENTIAL WITH ANY STORM. BUT FOR NOW...THINK ISOLATED
MARGINALLY SEVERE MICROBURSTS COULD OCCUR AND WILL MENTION THIS
SLIGHT THREAT IN THE HWO. HAVE INCREASING POPS THROUGHOUT THE DAY
AND LATER TONIGHT AS THE CONVECTIVE FOCUS SHIFTS FROM WEST TO EAST
THROUGH SATURDAY.

MID-UPPER LEVEL WARMING WILL INCREASE SATURDAY-SUNDAY AS RIDGING
STARTS TO PUSH INTO THE REGION...BUT PROGGED SOUNDINGS ARE STILL
QUITE UNSTABLE. EVEN THE WEAKER NAM SOUNDINGS SHOW UP TO 2200 J/KG
OF CAPE BY SUNDAY AFTERNOON. WITH THE UPPER LOW EXITING WEST TO
EAST...WILL SLOWLY TAPER POPS THRU SUNDAY...BUT MAY MENTION A SLIGHT
SEVERE STORMS RISK IN THE HWO BOTH AFTERNOON-EVENINGS THIS WEEKEND.

BY SUNDAY NIGHT AND INTO MONDAY...RIDGING SHOULD DRY US OUT FOR A
COUPLE DAYS BEFORE A STRONG UPPER LOW OVER THE NW CONUS DROPS SE
INTO THE PLAINS AND DEVELOPS A SFC LOW AND ASSOCIATED COLD FRONT.
WITH A STRONG SFC HIGH OVER THE SERN US...GOOD SOUTHERLY FLOW WILL
INCREASE TEMPS/DEWPOINTS EARLY NEXT WEEK AND LIKELY DELAY THE
APPROACH OF THE SFC LOW AND COLD FRONT OVER THE PLAINS. FOR
NOW...SLOWLY INCREASE POPS FROM THE NW BEGINNING TUES AND LASTING
INTO WEDNESDAY...WITH WED HAVING LOW LIKELY POPS AS THE COLD FRONT
APPROACHES. BEHIND THE FRONT...NOT MUCH CONFIDENCE IN THE FORECAST
THEREAFTER AS THE GFS PUSHES RIDGING IN FAST KEEPING THE LAGGING
UPPER LOW OFF TO OUR NORTH AND PRECIP CHANCES NIL. THE EURO ON THE
OTHER HAND STRENGTHENS THE UPPER LOW OVER THE MIDWEST...KEEPING THE
UPPER RIDGING AT BAY TO OUR WEST. FOR NOW HAVE SLIGHT CHC POPS AND
MODERATING TEMPS FOR THRS AND FRI UNTIL ENSEMBLE DATA CAN SHED SOME
LIGHT ON A PARTICULAR SOLUTION.

&&

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

$$