000
FXUS64 KOHX 220746
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
246 AM CDT WED MAY 22 2013

.DISCUSSION...
CURRENT SETUP...UPPER TROUGH TAKING ON NEGATIVE TILT THROUGH THE MID-
LEVELS BASED ON LATEST RUC WITH THE COLDER AIR ALOFT REMAINING
BACK OVER CENTRAL PLAINS NOSING DOWN INTO ARKANSAS. A 35 TO 40
KNOT LOW LEVEL JET WAS CONTINUING TO FEED MOIST PLUME INTO MIDDLE
TENNESSEE. WIND FIELD LOOKS TO BE UNIDIRECTIONAL WITH SPEED SHEAR IN
THE LOWER TROPOSPHERE. UPPER LEVEL JET JUST RUNNING NORTH TO SOUTH
FROM ABOUT TEXARKANA NORTHWARD INTO IOWA WITH A 65 KNOT MID LEVEL
JET CUTTING ACROSS CENTRAL ARKANSAS. ON-GOING CONVECTION CURRENTLY
ACROSS FAR WESTERN KENTUCKY...WESTERN TENNESSEE AND DOWN THROUGH
MISSISSIPPI...BEEN SHOWING SIGNS OF WEAKENING LAST COUPLE OF HOURS
AS CLOUD TOPS CONTINUE TO WARM.

WITH THE CURRENT SETUP LOOKS LIKE SHOWERS AND STORMS WILL BE
LIKELY DURING THE DAY...WITH A FEW STRONG TO SEVERE STORMS
POSSIBLE...ESPECIALLY MID-DAY THROUGH THE AFTERNOON AND INTO THE
EARLY EVENING HOURS. THINK THE MAIN THREAT WILL BE DAMAGING WINDS AND
LARGE HAIL BUT ISOLATED TORNADOES ARE ALSO POSSIBLE. EVEN THOUGH
THE WIND FIELDS ARE UNIDIRECTIONAL THE SWEAT INDEX CLIMBS TO 362
AT 18Z AND 413 BY 00Z WITH MID-LEVEL DRYING IN PLACE DURING THE
MID-DAY THROUGH THE AFTERNOON/EARLY EVENING.

ON THURSDAY A SHORT WAVE ON THE BACK SIDE OF UPPER TROUGH WILL
DROP DOWN THROUGH THE OHIO VALLEY AND BRING A CHANCE FOR SHOWERS
AND ISOLATED THUNDERSTORMS MAINLY TO THE NORTHEAST HALF DURING THE
AFTERNOON WITH A SLIGHT CHANCE REMAINING ALONG THE PLATEAU
THURSDAY NIGHT. MUCH OF THE MEMORIAL DAY WEEKEND LOOKS DRY HOWEVER
MODELS HAVE BEEN DIFFERING. GFS HAS WARM FRONT DRAPED ACROSS THE
OHIO VALLEY THROUGH THE WEEKEND WHICH WOULD KEEP MID STATE
BASICALLY WARM AND DRY. THE EURO HAS WARM FRONT DRAPED THROUGH
WESTERN TENNESSEE INTO NORTHERN ALABAMA AND KEEPS SHOWERS AND
STORMS IN THE MID STATE JUST ABOUT EACH DAY THROUGH THE MEMORIAL
DAY WEEKEND. HAVE OPTED TO GO WITH GFS FOR THIS FORECAST PACKAGE.

HAVE BACKED OFF A TAD FROM MAV MOS ON HIGHS TODAY AND WENT CLOSER
TO THE MET DUE TO CLOUD COVER AND SHOWER/STORM CHANCES. STAYED
CLOSE TO MOS GUIDANCE THROUGH REMAINDER OF FORECAST.

BOYD

&&

.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE      79  61  78  52 /  60  30  20  10
CLARKSVILLE    76  58  76  49 /  60  20  20  10
CROSSVILLE     76  59  73  51 /  70  50  30  20
COLUMBIA       79  61  80  54 /  60  30  20  10
LAWRENCEBURG   78  60  80  55 /  60  30  20  10
WAVERLY        77  59  77  50 /  60  20  20  10

&&

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

$$
BOYD
01

000
FXUS64 KMRX 220740
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
340 AM EDT WED MAY 22 2013

.SHORT TERM (TODAY AND TONIGHT)...MORE CONVECTION EXPECTED TODAY
WITH PLENTY OF SHORT WAVE ENERGY ROTATING THROUGH THE MEAN UPPER
LEVEL TROUGH ACROSS MID AMERICA. WITH SOME HEATING AHEAD OF THE MAIN
FEATURE...CURRENTLY BUILDING NORTHEAST THROUGH WEST TENNESSEE AND
NORTHERN MISSISSIPPI...MODELS PROG RATHER DECENT INSTABILITY WITH
CAPES BUMPING UP TO AROUND 2000 J/KG OR HIGHER AND LIFTED INDICES AS
HIGH AS -8 BY EARLY AFTERNOON. BULK SHEAR NOT QUITE AS IMPRESSIVE
BUT STILL AROUND 30 TO 35 KTS MUCH OF THE FORECAST AREA WITH VALUES
APPROACHING 40 KTS ON THE PLATEAU DURING THE AFTERNOON.
THEREFORE...THERE IS A CHANCE FOR SEVERE CONVECTION MID DAY ON THE
PLATEAU AND POINTS EAST THROUGH THE AFTERNOON. HELICITY VALUES NOT
TERRIBLY IMPRESSIVE SO THREAT FOR TORNADOES WILL BE REDUCED. MODELS
SHOW WEAKENING FRONTAL BOUNDARY BUILDING INTO THE REGION TONIGHT
WITH ADDITIONAL SHORT WAVE ENERGY SWINGING ACROSS THE AREA SO WENT
WITH LIKELY PROBABILITIES FOR ADDITIONAL SHOWERS AND THUNDERSTORMS
MAINLY THROUGH LATE EVENING WITH PERCENTAGES DROPPING OFF AFTER
MIDNIGHT. TRIED TO STAY CLOSE A GUIDANCE BLEND FOR MAX TEMPS DURING
THE SHORT TERM WITH MAV MAXES A BIT TOO WARM MOST AREAS. STAYED
CLOSER TO THE MILDER MIN GUIDANCE TONIGHT.

.LONG TERM...(THURSDAY THROUGH TUESDAY)...UPPER TROUGH WILL MOVE
ACROSS THE OHIO AND TENNESSEE VALLEYS THURSDAY ALONG WITH A
SECONDARY COLD FRONT THAT WILL USHER IN UNSEASONABLY COOL AIR INTO
THE SOUTHERN APPALACHIANS. FORECAST SOUNDINGS SHOW AIR-MASS WILL
ONCE AGAIN BECOME MARGINALLY UNSTABLE WITH CAPES OF 1000-1500 J/KG
DURING THE AFTENOON. BEST INSTABILITY AND MOISTURE WILL BE ACROSS
THE NORTHERN HALF OF THE FORECAST AREA. HAVE INCLUDE LIKELY POPS
NORTH TO LOW-CHANCE SOUTH FOR THURSDAY AFTERNOON.

MODELS SHOW A GOOD DEAL OF COLD-AIR STRATU-CU AND SOME OROGRAPHIC
LIFT FOR THURSDAY NIGHT-ENDING FRIDAY MORNING. WILL MAINTAIN A GOOD
DEAL OF CLOUD-COVER AS WELL SCATTERED SHOWS. BEST CHANCES OVER THE
HIGHER TERRAIN WHERE NORTHWEST FLOW WILL PRODUCE OROGRAPHIC LIFT.

FOR FRIDAY THROUGH THE WEEKEND...UNSEASONABLY COOL AND DRY AIR-MASS
WILL BE RULE ACROSS THE SOUTHERN APPALACHIANS. WOULD NOT BE
SURPRISED TO SEE SOME FROST ACROSS THE NORTHEAST AND MOUNTAINS
FRIDAY NIGHT.

FOR EARLY NEXT WEEK..THE GFS AND ECMWF DIFFER GREATLY ON WHERE AND
EXTENT OF CONVECTION ALONG DEVELOPING WARM FRONTAL BOUNDARY ACROSS
THE OHIO AND TENNESSEE VALLEYS. THE ECMWF IS MUCH MORE AGGRESSIVE.
WILL TREND TOWARD THE GFS..BUT SOME ENSEMBLE MEMBERS DO AGREE WITH
SOME HIGHER POPS.

GENERALLY FOLLOWED THE GFS MOS THROUGH THE FORECAST PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             84  62  83  57  73 /  70  60  20  20   0
KNOXVILLE MCGHEE TYSON AIRPORT, TN  84  63  80  56  71 /  70  60  50  30  10
OAK RIDGE, TN                       84  62  80  55  72 /  70  60  50  30  10
TRI CITIES AIRPORT, TN              85  61  78  54  67 /  70  60  60  50  10

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

000
FXUS64 KMRX 220558
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
158 AM EDT WED MAY 22 2013

.AVIATION...LOOKS LIKE AVIATION WILL BE IMPACTED BY CONVECTION
TODAY IN THE GREAT VALLEY AS MODELS INDICATE TWO OR THREE SHORTER
WAVELENGTH FEATURES WILL BUILD ACROSS THE SOUTHERN APPALACHIAN
REGION IN VERY SLOW WEATHER PATTERN GOVERNED BY MID AMERICAN UPPER
LEVEL TROUGH. SOME ISOLATED CONVECTION ALIGNED ON THE WESTERN
PLATEAU DOESN`T APPEAR TO IMPACT THE TERMINALS THROUGH THE FIRST
SEVERAL HOURS OF THE FORECAST. AVIATION WILL MOST LIKELY BE
AFFECTED AROUND MID DAY THROUGH THE AFTERNOON AS LIFT WITH INITIAL
WAVE DRIVING CONVECTION ACROSS WEST TENNESSEE AND NORTHERN
MISSISSIPPI HEADS EAST. DECENT AMOUNT OF JUICE AVAILABLE IN
UNSTABLE ENVIRONMENT FOR STORMS SO JUST WENT AHEAD AND USED A
PREVAILING CONVECTIVE GROUP FOR THE MAIN EVENT AT THE TERMINALS.
APPLIED SOME POST EVENT VICINITY SHOWERS FOR THE LATER EVENING
PERIOD. LOOKS LIKE BEST BET FOR SOME MVFR/IFR FOG WILL BE AT TRI
WHERE DEBRIS CLOUDS FROM TUESDAY NIGHT STORMS MOVES AWAY TO THE
EAST ALLOWING FOR SOME RADIATION.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

000
FXUS64 KMEG 220437
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1137 PM CDT TUE MAY 21 2013

.DISCUSSION...

UPDATED FOR 06Z AVIATION DISCUSSION

&&

.PREV DISCUSSION... /ISSUED 807 PM CDT TUE MAY 21 2013/

UPDATE...

A LINE OF SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE EAST ACROSS
WEST TENNESSEE AND NORTH MISSISSIPPI. THE ATMOSPHERE ACROSS WEST
TENNESSEE HAS BEEN WORKED OVER AND THUS FAR THE STORMS HAVE NOT
APPROACHED SEVERE LIMITS. MEANWHILE FURTHER SOUTH...THE LINE IS
JUST GETTING INTO NORTHEAST MISSISSIPPI WHERE THE ATMOSPHERE IS
MUCH MORE UNSTABLE SINCE NO RAIN HAS FALLEN ACROSS THE AREA TODAY.
IN ADDITION...THE SECOND LINE OF SHOWERS AND THUNDERSTORMS
ASSOCIATED WITH THE UPPER SHORTWAVE IS BEGINNING TO TO STREAM
NORTHWARD ACROSS SOUTHEAST ARKANSAS. DON/T KNOW WHAT THE STORMS
WILL DO WHEN THEY MOVE INTO NORTHWEST MISSISSIPPI AS THE
ATMOSPHERE HAS BEEN WORKED OVER FROM FIRST LINE. HOWEVER...SEVERE
THUNDERSTORM WARNINGS CONTINUE TO BE ISSUED ALONG PORTIONS OF THE
LINE SO WILL HANG ON TO THE WATCH FOR NORTH MISSISSIPPI AFTER THE
FIRST LINE MOVES THROUGH UNTIL WE SEE WHAT THE STORMS DO ALONG THE
SECOND LINE. HOWEVER...WILL CONTINUE TO CLEAR THE WATCH BEHIND THE
FIRST LINE ACROSS WEST TENNESSEE.

KRM

DISCUSSION... /ISSUED 304 PM CDT TUE MAY 21 2013/

VERY ACTIVE RADAR THIS AFTERNOON. OVERNIGHT/EARLY MORNING
CONVECTION MAY HAVE US FROM A MUCH MORE SIGNIFICANT SEVERE WEATHER
OUTBREAK TODAY...ALTHOUGH SEVERE POTENTIAL STILL
EXISTS...ESPECIALLY ACROSS NORTH MISSISSIPPI. FARTHER NORTH THE
AIRMASS HAS BEEN WORKED OVER...AND ABUNDANT CLOUD COVER HAS KEPT
TEMPERATURES QUITE A BIT COOLER. INSTABILITY IS HIGHEST IN NORTH
MISSISSIPPI WHERE TEMPERATURES HAVE BEEN ABLE TO CLIMB INTO THE
MIDDLE AND UPPER 80S. DEW POINTS ARE IN THE UPPER 60S TO LOWER 70S
RESULTING IN CAPES IN EXCESS OF 2500 J/KG AND LI`S BELOW -6C. JUST
ACROSS THE STATE LINE IN MOST OF TN...THE MISSOURI BOOTHEEL AND
NORTHEAST ARKANSAS...CAPES ARE GENERALLY BELOW 1500 J/KG WITH LI`S
-4C OR GREATER. DEW POINTS ARE ALSO SLIGHTLY HIGHER. IN THE PAST
COUPLE OF HOURS STORMS HAVE DEVELOPED IN NORTH MISSISSIPPI AND
HAVE SHOWN SOME SIGNS OF ROTATION. 0-3KM HELICITY IS GENERALLY
50-90M^2/S^2 WHICH WOULD CERTAINLY SUPPORT ROTATING STORMS. UPPER
LEVEL SUPPORT IS NOT CURRENTLY AS FAVORABLE FOR SEVERE
THUNDERSTORMS...ALTHOUGH BETTER SUPPORT IS EXPECTED TO MOVE IN
TONIGHT.

ANOTHER ROUND OF STORMS CAN BE SEEN OVER NORTH TEXAS INTO
OKLAHOMA. THIS LINE WILL BRING ADDITIONAL SHOWERS AND
THUNDERSTORMS TO THE MIDSOUTH OVERNIGHT. NUMEROUS OUTFLOW
BOUNDARIES WILL ONLY HELP SUPPORT FOCUS UPDRAFTS AND MAINTAIN A
SEVERE THREAT.

A SHORTWAVE TROUGH CURRENTLY OVER THE TEXAS AND OKLAHOMA
PANHANDLES WILL SHIFT TO THE EAST THIS EVENING AND APPROACH THE
MISSISSIPPI RIVER BY SUNRISE. A SURFACE LOW HAS DEVELOPED OVER
NORTH TEXAS AND SHOULD TRACK NORTHEAST ACROSS CENTRAL ARKANSAS
DURING THE NIGHT. WE WILL SEE A 40-45KT LLJ DEVELOP BY MIDNIGHT
AND MUCH OF THE MIDSOUTH WILL BE IN THE RIGHT ENTRANCE REGION OF A
70-80KT UPPER LEVEL JET. THIS ADDITIONAL DYNAMIC SUPPORT WILL MOVE
IN JUST AS WE LOSE DAYTIME THERMODYNAMIC SUPPORT. THUS FEEL LIKE
THE THREAT FOR SEVERE WEATHER WILL REMAIN ABOUT THE SAME DURING
THE NIGHT...MARGINAL BUT CERTAINLY NOT ZERO.

RESEARCHERS AT MISSISSIPPI STATE UNIVERSITY LAUNCHED A WEATHER
BALLOON MIDDAY ABOUT 30 MILES SOUTHWEST OF GREENWOOD MISSISSIPPI.
IT SHOWS A BIT OF A CAP AT 10KFT...BUT CAPE IN EXCESS OF 3500
J/KG. FARTHER NORTH AT LITTLE ROCK A MIDDAY SOUNDING WAS
INDICATIVE OF A WORKED OVER ENVIRONMENT...FEATURING ONLY 343
JOULES OF CAPE. ANY THREATS FROM STORMS IN WEST TENNESSEE AND EAST
ARKANSAS WOULD BE PRIMARILY HAIL.

A COLD FRONT WILL SWEEP ACROSS THE MIDSOUTH TOMORROW BRINGING AN
END TO THE PRECIPITATION. THE FRONT SHOULD MOVE INTO EAST ARKANSAS
BY 10 AM...CROSS THE MISSISSIPPI RIVER MIDDAY AND EXIT INTO
CENTRAL TENNESSEE/NORTH ALABAMA DURING THE MID AFTERNOON HOURS.
RAIN WILL LIKELY LIMIT TEMPERATURES AGAIN TOMORROW BUT AS RAIN
ENDS...WE COULD SEE TEMPERATURES SURGE INTO THE LOW 80S DURING THE
AFTERNOON HOURS. THE DIURNAL TEMPERATURE PROFILE WILL LIKELY BE
TRICKY TOMORROW DUE THE RAINFALL AND FRONT.

THURSDAY THROUGH THE WEEKEND LOOK MOSTLY DRY. TEMPERATURES THURSDAY
WILL BE NEAR NORMAL...WITH COOLISH FRIDAY...THEN TRENDING
GRADUALLY WARMER THROUGH THE WEEKEND. FRIDAY THROUGH THE WEEKEND
OUR WEATHER SHOULD BE PRIMARILY INFLUENCED BY A WEAK RIDGE ALOFT
AND SURFACE HIGH PRESSURE RESULTING IN DRY CONDITIONS.

&&

.AVIATION...

06Z TAF CYCLE

A LINE OF STRONG TSRAS WILL MOVE THROUGH KTUP BETWEEN 22/06Z-22/08Z
FOLLOWED BY A LARGE AREA OF STRATIFORM RAIN. THIS RAIN WILL MOVE
OUT OF KJBR SHORTLY AND OUT OF KMEM AND KMKL OVER THE NEXT COUPLE
OF HOURS. AFTER THE TSRAS MOVE THROUGH KTUP EXPECT MAINLY VFR
CONDS FOR THE REST OF THE OVERNIGHT PERIOD. LATEST MODELS
INDICATE MORE SHRAS DEVELOPING OVER ARKANSAS AND MOVING ACROSS
THE MIDSOUTH BTWN 22/10Z AT KJBR AND 22/14Z AT KTUP. A PERIOD OF
MVFR CIGS IS LIKELY ACROSS THE AREA WED MORNING AS WELL. CONDS
WILL IMPROVE TO VFR BY WED AT AROUND NOON AND CONTINUE THROUGH THE
REMAINDER OF THE PERIOD.

GENERALLY LIGHT SOUTH WINDS OVERNIGHT BECOMING SW AT 10-12 KTS WED
MORNING.

SJM

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  66  83  61  82 / 100  60  10  10
MKL  64  81  58  81 / 100  60  10  10
JBR  63  82  57  80 / 100  40  10  10
TUP  64  83  60  86 / 100  70  10  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KOHX 220426
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1126 PM CDT TUE MAY 21 2013

.UPDATE...FOR 06Z AVIATION FORECASTS.

&&

.AVIATION...BKN LINE OF CONVECTION STILL ONGOING BETWEEN BNA AND
CSV, WITH A GUST FRONT DUE TO ARRIVE AT CSV AROUND 06Z, ALONG WITH
A BRIEF PERIOD OF GUSTY NORTH SFC WINDS TO NR 15KTS. EXPECT VCTS TO
EXIST IN CSV AREA UNTIL 07Z. OTHERWISE, EXPECT MVFR CONDITIONS TO
PREVAIL, DUE TO BR, AT ALL MID STATE TERMINALS THROUGH ABOUT 13Z.
BEST CHANCE FOR NEXT ROUND OF TSTMS WILL BE DURING THE LATE
MORNING AND AFTERNOON HOURS ON WEDNESDAY (IN SIMILAR FASHION TO
TUESDAY), WITH ANOTHER RECURRENCE OF MVFR CONDITIONS, DUE TO BR,
AFTER 03Z/23.

&&

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

$$

19

000
FXUS64 KOHX 220217
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
917 PM CDT TUE MAY 21 2013

.MESOSCALE UPDATE...THUNDERSTORMS CONTINUE TO MOVE ACROSS OUR
WESTERN COUNTIES...LIKELY PRODUCING 40 MPH WIND GUSTS...SMALL
HAIL AND HEAVY DOWNPOURS. THE AREA IS MOVING EAST 30-35 MPH. THE
STORMS STILL HAVE THE POTENTIAL TO FLARE UP BRIEFLY WITH WIND
GUSTS OVER THE NEXT HOUR OR 2...BUT THE TREND SHOULD BE FOR
WEAKENING AS THEY APPROACH MORE STABLE AIR ALONG AND EAST OF I 65.
WE ARE CONCERNED WITH LOCALIZED FLOODING FROM THE HEAVY DOWNPOURS
AND THE MODERATE RAIN AREAS TRAILING THE MAIN BAND OF STORMS.

LOTS OF STORMS ONGOING FROM THE MID SOUTH BACK TO TX. IT LOOKS
LIKE THESE SOUTHERN STORMS ARE GOING TO CUT OFF LATE NIGHT ACTIVITY
FARTHER NORTH. SO...ALTHOUGH WE MAY SEE SHOWERS AND STORMS LATE
INTO THE NIGHT...IT APPEARS THERE NOT BE ANY ADDITIONAL LINES OF
STRONG TO SEVERE AFTER THIS INITIAL ONE.

13

&&

.PREV DISCUSSION... /ISSUED 306 PM CDT TUE MAY 21 2013/

DISCUSSION...

..STRONG TO SEVERE STORMS POSSIBLE ON AND OFF THROUGH WEDNESDAY
AFTERNOON-EVENING...

CURRENTLY...AN AREA OF SHOWERS AND STORMS OVER EASTERN MIDDLE TN
CONTINUES TO PRODUCE TORRENTIAL RAINFALL AND MARGINALLY SEVERE
HAIL OR JUST UNDER SEVERE LIMITS...AS WELL AS ISOLATED DAMAGING
WIND GUSTS. THE STORM PREDICTION CENTER HAS ISSUED A SEVERE
T-STORM WATCH OVER OUR FIVE FAR EASTERN COUNTIES UNTIL 02Z...BUT
WE WILL BE ABLE TO CANCEL THAT WELL BEFORE THEN. STRONG TO
POSSIBLY SEVERE CELLS WILL CONTINUE THERE FOR THE NEXT 1-2 HOURS.

ANOTHER LINE OF STRONG STORMS IS CURRENTLY OVER ARKANSAS AND THIS
WILL PUSH EAST INTO MIDDLE TN MOSTLY LIKELY WELL AFTER 00Z. A FEW
ISOLATED STORMS STREAMING NORTH AHEAD OF THIS SECOND LINE THOUGH
COULD SQUEAK INTO SOUTHWEST MIDDLE TN AND BE CAPABLE OF PRODUCING
STRONG WINDS/HAIL THIS AFTERNOON-EVENING. SO FOR THE REST OF
TODAY...THE FOCUS ON SEVERE WEATHER WILL SHIFT FROM OUR FAR EAST
TO OUR SOUTHWEST THROUGH 7PM-ISH.

TONIGHT...THE LINE OF CONVECTION PUSHING OUT OF ARKANSAS WILL
LIKELY BE OVERTAKEN BY CONVECTION IN EASTERN OK. THE SOUTHERN
PORTION OF THE LINE WILL LIKELY TAKE OVER AS WE HAVE STABILIZED
FROM TODAY`S CONVECTION. THUS...WOULD NOT BE SURPRISED TO SEE THIS
LINE APPROACH MIDDLE TN LATE TONIGHT-EARLY WEDNESDAY MORNING AND
WEAKEN CONSIDERABLY IF NOT DISSIPATE COMPLETELY. EITHER OCCURRENCE
WILL YIELD ANOTHER CHANCE TO DESTABILIZE AHEAD OF THE UPPER LEVEL
LOW...WITH MORE STRONG TO SEVERE STORMS POSSIBLE WEDNESDAY LATE
MORNING BUT ESPECIALLY IN THE AFTERNOON. WE`LL HAVE BETTER SHEAR
IN PLACE AS WELL...WITH THE BEST CHANCE OF SEVERE ALONG AND EAST
OF I-65. SPC PLACED US IN A DAY TWO SLIGHT RISK...AGAIN WITH THE
MAIN THREATS BEING DAMAGING WINDS AND LARGE HAIL. ALTHOUGH THE SFC
BOUNDARY WILL PUSH EAST OF THE AREA WEDNESDAY NIGHT...MORE SHOWERS
AND STORMS (LIKELY NON-SEVERE) WILL ACCOMPANY THE TRAILING UPPER
LOW THROUGH THURSDAY AND WE WILL FINALLY DRY OUT THURSDAY NIGHT
WEST TO EAST.

THEREAFTER...LOTS OF QUESTION WHETHER OR NOT WE DRY OUT AND RIDGE
OUT VIA THE GFS...OR THE WARM FRONT FROM A PLAINS LOW EXTENDS
EASTWARD INTO MIDDLE TN...KEEPING CHANCES OF RAIN ACROSS THE AREA
OVER THE WEEKEND INTO EARLY NEXT WEEK. FOR NOW HAVE SLIGHT CHC
POPS OVER THE NE SUNDAY NIGHT-MONDAY. FOR TEMPS...WENT WITH LOWER-
THAN-MEX IN CASE EURO PANS OUT.

&&

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

&&

$$

000
FXUS64 KMRX 220214
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1014 PM EDT TUE MAY 21 2013

.DISCUSSION...MCS HAS WEAKENED AND MOVED NE OF THE AREA. PATCHY FOG
WILL LIKELY DEVELOP OVERNIGHT. CURRENT FORECAST MINS LOOK GOOD. LOW
CONFIDENCE IN CURRENT MODEL RUNS PERTAINING TO CONVECTION. EXPECT
SIMILAR CONDITIONS ON WEDNESDAY WITH A CHANCE OF STRONG TO SEVERE
STORMS. ONGOING CONVECTION OVER MID TN WILL CONTINUED TO BE
MONITORED.


&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             66  84  63  81  57 /  20  60  50  30  20
KNOXVILLE MCGHEE TYSON AIRPORT, TN  65  84  62  80  56 /  20  60  50  40  30
OAK RIDGE, TN                       65  84  62  81  56 /  20  60  50  40  30
TRI CITIES AIRPORT, TN              61  83  61  79  55 /  30  50  50  50  40

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

SON

000
FXUS64 KMEG 220107
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
807 PM CDT TUE MAY 21 2013

.UPDATE...

A LINE OF SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE EAST ACROSS
WEST TENNESSEE AND NORTH MISSISSIPPI. THE ATMOSPHERE ACROSS WEST
TENNESSEE HAS BEEN WORKED OVER AND THUS FAR THE STORMS HAVE NOT
APPROACHED SEVERE LIMITS. MEANWHILE FURTHER SOUTH...THE LINE IS
JUST GETTING INTO NORTHEAST MISSISSIPPI WHERE THE ATMOSPHERE IS
MUCH MORE UNSTABLE SINCE NO RAIN HAS FALLEN ACROSS THE AREA TODAY.
IN ADDITION...THE SECOND LINE OF SHOWERS AND THUNDERSTORMS
ASSOCIATED WITH THE UPPER SHORTWAVE IS BEGINNING TO TO STREAM
NORTHWARD ACROSS SOUTHEAST ARKANSAS. DON/T KNOW WHAT THE STORMS
WILL DO WHEN THEY MOVE INTO NORTHWEST MISSISSIPPI AS THE
ATMOSPHERE HAS BEEN WORKED OVER FROM FIRST LINE. HOWEVER...SEVERE
THUNDERSTORM WARNINGS CONTINUE TO BE ISSUED ALONG PORTIONS OF THE
LINE SO WILL HANG ON TO THE WATCH FOR NORTH MISSISSIPPI AFTER THE
FIRST LINE MOVES THROUGH UNTIL WE SEE WHAT THE STORMS DO ALONG THE
SECOND LINE. HOWEVER...WILL CONTINUE TO CLEAR THE WATCH BEHIND THE
FIRST LINE ACROSS WEST TENNESSEE.

KRM

&&

.DISCUSSION... /ISSUED 304 PM CDT TUE MAY 21 2013/

VERY ACTIVE RADAR THIS AFTERNOON. OVERNIGHT/EARLY MORNING
CONVECTION MAY HAVE US FROM A MUCH MORE SIGNIFICANT SEVERE WEATHER
OUTBREAK TODAY...ALTHOUGH SEVERE POTENTIAL STILL
EXISTS...ESPECIALLY ACROSS NORTH MISSISSIPPI. FARTHER NORTH THE
AIRMASS HAS BEEN WORKED OVER...AND ABUNDANT CLOUD COVER HAS KEPT
TEMPERATURES QUITE A BIT COOLER. INSTABILITY IS HIGHEST IN NORTH
MISSISSIPPI WHERE TEMPERATURES HAVE BEEN ABLE TO CLIMB INTO THE
MIDDLE AND UPPER 80S. DEW POINTS ARE IN THE UPPER 60S TO LOWER 70S
RESULTING IN CAPES IN EXCESS OF 2500 J/KG AND LI`S BELOW -6C. JUST
ACROSS THE STATE LINE IN MOST OF TN...THE MISSOURI BOOTHEEL AND
NORTHEAST ARKANSAS...CAPES ARE GENERALLY BELOW 1500 J/KG WITH LI`S
-4C OR GREATER. DEW POINTS ARE ALSO SLIGHTLY HIGHER. IN THE PAST
COUPLE OF HOURS STORMS HAVE DEVELOPED IN NORTH MISSISSIPPI AND
HAVE SHOWN SOME SIGNS OF ROTATION. 0-3KM HELICITY IS GENERALLY
50-90M^2/S^2 WHICH WOULD CERTAINLY SUPPORT ROTATING STORMS. UPPER
LEVEL SUPPORT IS NOT CURRENTLY AS FAVORABLE FOR SEVERE
THUNDERSTORMS...ALTHOUGH BETTER SUPPORT IS EXPECTED TO MOVE IN
TONIGHT.

ANOTHER ROUND OF STORMS CAN BE SEEN OVER NORTH TEXAS INTO
OKLAHOMA. THIS LINE WILL BRING ADDITIONAL SHOWERS AND
THUNDERSTORMS TO THE MIDSOUTH OVERNIGHT. NUMEROUS OUTFLOW
BOUNDARIES WILL ONLY HELP SUPPORT FOCUS UPDRAFTS AND MAINTAIN A
SEVERE THREAT.

A SHORTWAVE TROUGH CURRENTLY OVER THE TEXAS AND OKLAHOMA
PANHANDLES WILL SHIFT TO THE EAST THIS EVENING AND APPROACH THE
MISSISSIPPI RIVER BY SUNRISE. A SURFACE LOW HAS DEVELOPED OVER
NORTH TEXAS AND SHOULD TRACK NORTHEAST ACROSS CENTRAL ARKANSAS
DURING THE NIGHT. WE WILL SEE A 40-45KT LLJ DEVELOP BY MIDNIGHT
AND MUCH OF THE MIDSOUTH WILL BE IN THE RIGHT ENTRANCE REGION OF A
70-80KT UPPER LEVEL JET. THIS ADDITIONAL DYNAMIC SUPPORT WILL MOVE
IN JUST AS WE LOSE DAYTIME THERMODYNAMIC SUPPORT. THUS FEEL LIKE
THE THREAT FOR SEVERE WEATHER WILL REMAIN ABOUT THE SAME DURING
THE NIGHT...MARGINAL BUT CERTAINLY NOT ZERO.

RESEARCHERS AT MISSISSIPPI STATE UNIVERSITY LAUNCHED A WEATHER
BALLOON MIDDAY ABOUT 30 MILES SOUTHWEST OF GREENWOOD MISSISSIPPI.
IT SHOWS A BIT OF A CAP AT 10KFT...BUT CAPE IN EXCESS OF 3500
J/KG. FARTHER NORTH AT LITTLE ROCK A MIDDAY SOUNDING WAS
INDICATIVE OF A WORKED OVER ENVIRONMENT...FEATURING ONLY 343
JOULES OF CAPE. ANY THREATS FROM STORMS IN WEST TENNESSEE AND EAST
ARKANSAS WOULD BE PRIMARILY HAIL.

A COLD FRONT WILL SWEEP ACROSS THE MIDSOUTH TOMORROW BRINGING AN
END TO THE PRECIPITATION. THE FRONT SHOULD MOVE INTO EAST ARKANSAS
BY 10 AM...CROSS THE MISSISSIPPI RIVER MIDDAY AND EXIT INTO
CENTRAL TENNESSEE/NORTH ALABAMA DURING THE MID AFTERNOON HOURS.
RAIN WILL LIKELY LIMIT TEMPERATURES AGAIN TOMORROW BUT AS RAIN
ENDS...WE COULD SEE TEMPERATURES SURGE INTO THE LOW 80S DURING THE
AFTERNOON HOURS. THE DIURNAL TEMPERATURE PROFILE WILL LIKELY BE
TRICKY TOMORROW DUE THE RAINFALL AND FRONT.

THURSDAY THROUGH THE WEEKEND LOOK MOSTLY DRY. TEMPERATURES THURSDAY
WILL BE NEAR NORMAL...WITH COOLISH FRIDAY...THEN TRENDING
GRADUALLY WARMER THROUGH THE WEEKEND. FRIDAY THROUGH THE WEEKEND
OUR WEATHER SHOULD BE PRIMARILY INFLUENCED BY A WEAK RIDGE ALOFT
AND SURFACE HIGH PRESSURE RESULTING IN DRY CONDITIONS.

&&

.AVIATION...
00Z TAF CYCLE

ONGOING LINE OF THUNDERSTORMS WILL MOVE EAST OF THE MIDSOUTH..LEAVING
MAINLY STRATIFORM RAIN WITH SOME EMBEDDED THUNDERSTORMS MOVING
THROUGH THE REGION OVERNIGHT. CEILINGS SHOULD REMAIN ABOVE 2000FT
AT ALL SITES. EXPECT CONDITIONS TO SLOWLY IMPROVE THRU MIDMORNING
TOMORROW.

SAK

&&


&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  69  83  61  82 / 100  60  10  10
MKL  67  81  58  81 / 100  60  10  10
JBR  65  82  57  80 / 100  40  10  10
TUP  67  83  60  86 / 100  70  10  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMEG 220102
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
802 PM CDT TUE MAY 21 2013

.UPDATE...

A LINE OF SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE EAST OF
ACROSS WEST TENNESSEE AND NORTH MISSISSIPPI. THE ATMOSPHERE ACROSS
WEST TENNESSEE HAS BEEN WORKED OVER AND THUS FAR THE STORMS HAVE
NOT APPROACHED SEVERE LIMITS. MEANWHILE FURTHER SOUTH...THE LINE
IS JUST GETTING INTO NORTHEAST MISSISSIPPI WHERE THE ATMOSPHERE IS
MUCH MORE UNSTABLE SINCE NO RAIN HAS FALLEN ACROSS THE AREA TODAY.
IN ADDITION...THE SECOND LINE OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH
THE UPPER SHORTWAVE IS BEGINNING TO TO STREAM NORTHWARD ACROSS
SOUTHEAST ARKANSAS. DON/T KNOW WHAT THE STORMS WILL DO WHEN THEY
MOVE INTO NORTHWEST MISSISSIPPI AS THE ATMOSPHERE HAS BEEN WORKED
OVER FROM FIRST LINE. HOWEVER...SEVERE THUNDERSTORM WARNINGS
CONTINUE TO BE ISSUED ALONG PORTIONS OF THE LINE SO WILL HANG ON
TO THE WATCH FOR NORTH MISSISSIPPI AFTER THE FIRST LINE MOVES
THROUGH UNTIL WE SEE WHAT THE STORMS DO ALONG THE SECOND LINE.
HOWEVER...WILL CONTINUE TO CLEAR THE WATCH BEHIND THE FIRST LINE
ACROSS WEST TENNESSEE.

KRM

&&

.DISCUSSION... /ISSUED 304 PM CDT TUE MAY 21 2013/

VERY ACTIVE RADAR THIS AFTERNOON. OVERNIGHT/EARLY MORNING
CONVECTION MAY HAVE US FROM A MUCH MORE SIGNIFICANT SEVERE WEATHER
OUTBREAK TODAY...ALTHOUGH SEVERE POTENTIAL STILL
EXISTS...ESPECIALLY ACROSS NORTH MISSISSIPPI. FARTHER NORTH THE
AIRMASS HAS BEEN WORKED OVER...AND ABUNDANT CLOUD COVER HAS KEPT
TEMPERATURES QUITE A BIT COOLER. INSTABILITY IS HIGHEST IN NORTH
MISSISSIPPI WHERE TEMPERATURES HAVE BEEN ABLE TO CLIMB INTO THE
MIDDLE AND UPPER 80S. DEW POINTS ARE IN THE UPPER 60S TO LOWER 70S
RESULTING IN CAPES IN EXCESS OF 2500 J/KG AND LI`S BELOW -6C. JUST
ACROSS THE STATE LINE IN MOST OF TN...THE MISSOURI BOOTHEEL AND
NORTHEAST ARKANSAS...CAPES ARE GENERALLY BELOW 1500 J/KG WITH LI`S
-4C OR GREATER. DEW POINTS ARE ALSO SLIGHTLY HIGHER. IN THE PAST
COUPLE OF HOURS STORMS HAVE DEVELOPED IN NORTH MISSISSIPPI AND
HAVE SHOWN SOME SIGNS OF ROTATION. 0-3KM HELICITY IS GENERALLY
50-90M^2/S^2 WHICH WOULD CERTAINLY SUPPORT ROTATING STORMS. UPPER
LEVEL SUPPORT IS NOT CURRENTLY AS FAVORABLE FOR SEVERE
THUNDERSTORMS...ALTHOUGH BETTER SUPPORT IS EXPECTED TO MOVE IN
TONIGHT.

ANOTHER ROUND OF STORMS CAN BE SEEN OVER NORTH TEXAS INTO
OKLAHOMA. THIS LINE WILL BRING ADDITIONAL SHOWERS AND
THUNDERSTORMS TO THE MIDSOUTH OVERNIGHT. NUMEROUS OUTFLOW
BOUNDARIES WILL ONLY HELP SUPPORT FOCUS UPDRAFTS AND MAINTAIN A
SEVERE THREAT.

A SHORTWAVE TROUGH CURRENTLY OVER THE TEXAS AND OKLAHOMA
PANHANDLES WILL SHIFT TO THE EAST THIS EVENING AND APPROACH THE
MISSISSIPPI RIVER BY SUNRISE. A SURFACE LOW HAS DEVELOPED OVER
NORTH TEXAS AND SHOULD TRACK NORTHEAST ACROSS CENTRAL ARKANSAS
DURING THE NIGHT. WE WILL SEE A 40-45KT LLJ DEVELOP BY MIDNIGHT
AND MUCH OF THE MIDSOUTH WILL BE IN THE RIGHT ENTRANCE REGION OF A
70-80KT UPPER LEVEL JET. THIS ADDITIONAL DYNAMIC SUPPORT WILL MOVE
IN JUST AS WE LOSE DAYTIME THERMODYNAMIC SUPPORT. THUS FEEL LIKE
THE THREAT FOR SEVERE WEATHER WILL REMAIN ABOUT THE SAME DURING
THE NIGHT...MARGINAL BUT CERTAINLY NOT ZERO.

RESEARCHERS AT MISSISSIPPI STATE UNIVERSITY LAUNCHED A WEATHER
BALLOON MIDDAY ABOUT 30 MILES SOUTHWEST OF GREENWOOD MISSISSIPPI.
IT SHOWS A BIT OF A CAP AT 10KFT...BUT CAPE IN EXCESS OF 3500
J/KG. FARTHER NORTH AT LITTLE ROCK A MIDDAY SOUNDING WAS
INDICATIVE OF A WORKED OVER ENVIRONMENT...FEATURING ONLY 343
JOULES OF CAPE. ANY THREATS FROM STORMS IN WEST TENNESSEE AND EAST
ARKANSAS WOULD BE PRIMARILY HAIL.

A COLD FRONT WILL SWEEP ACROSS THE MIDSOUTH TOMORROW BRINGING AN
END TO THE PRECIPITATION. THE FRONT SHOULD MOVE INTO EAST ARKANSAS
BY 10 AM...CROSS THE MISSISSIPPI RIVER MIDDAY AND EXIT INTO
CENTRAL TENNESSEE/NORTH ALABAMA DURING THE MID AFTERNOON HOURS.
RAIN WILL LIKELY LIMIT TEMPERATURES AGAIN TOMORROW BUT AS RAIN
ENDS...WE COULD SEE TEMPERATURES SURGE INTO THE LOW 80S DURING THE
AFTERNOON HOURS. THE DIURNAL TEMPERATURE PROFILE WILL LIKELY BE
TRICKY TOMORROW DUE THE RAINFALL AND FRONT.

THURSDAY THROUGH THE WEEKEND LOOK MOSTLY DRY. TEMPERATURES THURSDAY
WILL BE NEAR NORMAL...WITH COOLISH FRIDAY...THEN TRENDING
GRADUALLY WARMER THROUGH THE WEEKEND. FRIDAY THROUGH THE WEEKEND
OUR WEATHER SHOULD BE PRIMARILY INFLUENCED BY A WEAK RIDGE ALOFT
AND SURFACE HIGH PRESSURE RESULTING IN DRY CONDITIONS.

&&

.AVIATION...
00Z TAF CYCLE

ONGOING LINE OF THUNDERSTORMS WILL MOVE EAST OF THE MIDSOUTH..LEAVING
MAINLY STRATIFORM RAIN WITH SOME EMBEDDED THUNDERSTORMS MOVING
THROUGH THE REGION OVERNIGHT. CEILINGS SHOULD REMAIN ABOVE 2000FT
AT ALL SITES. EXPECT CONDITIONS TO SLOWLY IMPROVE THRU MIDMORNING
TOMORROW.

SAK

&&



&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  69  83  61  82 /  70  60  10  10
MKL  67  81  58  81 /  70  60  10  10
JBR  65  82  57  80 /  70  40  10  10
TUP  67  83  60  86 /  70  70  10  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMEG 220004
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
704 PM CDT TUE MAY 21 2013

.UPDATE...

.UPDATED FOR 00Z TAF DISCUSSION..

&&

.PREV DISCUSSION... /ISSUED 304 PM CDT TUE MAY 21 2013/

DISCUSSION...
VERY ACTIVE RADAR THIS AFTERNOON. OVERNIGHT/EARLY MORNING
CONVECTION MAY HAVE US FROM A MUCH MORE SIGNIFICANT SEVERE
WEATHER OUTBREAK TODAY...ALTHOUGH SEVERE POTENTIAL STILL
EXISTS...ESPECIALLY ACROSS NORTH MISSISSIPPI. FARTHER NORTH THE
AIRMASS HAS BEEN WORKED OVER...AND ABUNDANT CLOUD COVER HAS KEPT
TEMPERATURES QUITE A BIT COOLER. INSTABILITY IS HIGHEST IN NORTH
MISSISSIPPI WHERE TEMPERATURES HAVE BEEN ABLE TO CLIMB INTO THE
MIDDLE AND UPPER 80S. DEW POINTS ARE IN THE UPPER 60S TO LOWER 70S
RESULTING IN CAPES IN EXCESS OF 2500 J/KG AND LI`S BELOW -6C. JUST
ACROSS THE STATE LINE IN MOST OF TN...THE MISSOURI BOOTHEEL AND
NORTHEAST ARKANSAS...CAPES ARE GENERALLY BELOW 1500 J/KG WITH LI`S
-4C OR GREATER. DEW POINTS ARE ALSO SLIGHTLY HIGHER. IN THE PAST
COUPLE OF HOURS STORMS HAVE DEVELOPED IN NORTH MISSISSIPPI AND
HAVE SHOWN SOME SIGNS OF ROTATION. 0-3KM HELICITY IS GENERALLY
50-90M^2/S^2 WHICH WOULD CERTAINLY SUPPORT ROTATING STORMS. UPPER
LEVEL SUPPORT IS NOT CURRENTLY AS FAVORABLE FOR SEVERE
THUNDERSTORMS...ALTHOUGH BETTER SUPPORT IS EXPECTED TO MOVE IN
TONIGHT.

ANOTHER ROUND OF STORMS CAN BE SEEN OVER NORTH TEXAS INTO
OKLAHOMA. THIS LINE WILL BRING ADDITIONAL SHOWERS AND
THUNDERSTORMS TO THE MIDSOUTH OVERNIGHT. NUMEROUS OUTFLOW
BOUNDARIES WILL ONLY HELP SUPPORT FOCUS UPDRAFTS AND MAINTAIN A
SEVERE THREAT.

A SHORTWAVE TROUGH CURRENTLY OVER THE TEXAS AND OKLAHOMA
PANHANDLES WILL SHIFT TO THE EAST THIS EVENING AND APPROACH THE
MISSISSIPPI RIVER BY SUNRISE. A SURFACE LOW HAS DEVELOPED OVER
NORTH TEXAS AND SHOULD TRACK NORTHEAST ACROSS CENTRAL ARKANSAS
DURING THE NIGHT. WE WILL SEE A 40-45KT LLJ DEVELOP BY MIDNIGHT
AND MUCH OF THE MIDSOUTH WILL BE IN THE RIGHT ENTRANCE REGION OF A
70-80KT UPPER LEVEL JET. THIS ADDITIONAL DYNAMIC SUPPORT WILL MOVE
IN JUST AS WE LOSE DAYTIME THERMODYNAMIC SUPPORT. THUS FEEL LIKE
THE THREAT FOR SEVERE WEATHER WILL REMAIN ABOUT THE SAME DURING
THE NIGHT...MARGINAL BUT CERTAINLY NOT ZERO.

RESEARCHERS AT MISSISSIPPI STATE UNIVERSITY LAUNCHED A WEATHER
BALLOON MIDDAY ABOUT 30 MILES SOUTHWEST OF GREENWOOD MISSISSIPPI.
IT SHOWS A BIT OF A CAP AT 10KFT...BUT CAPE IN EXCESS OF 3500
J/KG. FARTHER NORTH AT LITTLE ROCK A MIDDAY SOUNDING WAS
INDICATIVE OF A WORKED OVER ENVIRONMENT...FEATURING ONLY 343
JOULES OF CAPE. ANY THREATS FROM STORMS IN WEST TENNESSEE AND EAST
ARKANSAS WOULD BE PRIMARILY HAIL.

A COLD FRONT WILL SWEEP ACROSS THE MIDSOUTH TOMORROW BRINGING AN
END TO THE PRECIPITATION. THE FRONT SHOULD MOVE INTO EAST ARKANSAS
BY 10 AM...CROSS THE MISSISSIPPI RIVER MIDDAY AND EXIT INTO
CENTRAL TENNESSEE/NORTH ALABAMA DURING THE MID AFTERNOON HOURS.
RAIN WILL LIKELY LIMIT TEMPERATURES AGAIN TOMORROW BUT AS RAIN
ENDS...WE COULD SEE TEMPERATURES SURGE INTO THE LOW 80S DURING THE
AFTERNOON HOURS. THE DIURNAL TEMPERATURE PROFILE WILL LIKELY BE
TRICKY TOMORROW DUE THE RAINFALL AND FRONT.

THURSDAY THROUGH THE WEEKEND LOOK MOSTLY DRY. TEMPERATURES THURSDAY
WILL BE NEAR NORMAL...WITH COOLISH FRIDAY...THEN TRENDING
GRADUALLY WARMER THROUGH THE WEEKEND. FRIDAY THROUGH THE WEEKEND
OUR WEATHER SHOULD BE PRIMARILY INFLUENCED BY A WEAK RIDGE ALOFT
AND SURFACE HIGH PRESSURE RESULTING IN DRY CONDITIONS.

AVIATION...
00Z TAF CYCLE

ONGOING LINE OF THUNDERSTORMS WILL MOVE EAST OF THE MIDSOUTH..LEAVING
MAINLY STRATIFORM RAIN WITH SOME EMBEDDED THUNDERSTORMS MOVING
THROUGH THE REGION OVERNIGHT. CEILINGS SHOULD REMAIN ABOVE 2000FT
AT ALL SITES. EXPECT CONDITIONS TO SLOWLY IMPROVE THRU MIDMORNING
TOMORROW.

SAK

&&




&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  69  83  61  82 /  70  60  10  10
MKL  67  81  58  81 /  70  60  10  10
JBR  65  82  57  80 /  70  40  10  10
TUP  67  83  60  86 /  70  70  10  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMRX 212327
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
727 PM EDT TUE MAY 21 2013

.AVIATION...STRONG CONVECTION MOVING NE FROM TYS AND WILL AFFECT TRI
WITH STRONG WINDS EARLY IN THE PERIOD. WINDS WILL DECREASE
OVERNIGHT ANDE BE MAINLY SOUTHWEST. CLOUDS AND LIGHT WINDS SHOULD
KEEP FOG AT BAY WITH MVFR CONDITIONS POSSIBLE. WINDS WILL INCREASE
WEDNESDAY TO NEAR 10 KTS IN ADVANCE OF AN APPROACHING COLD FRONT.
CONVECTIVE COVERAGE WILL INCREASE TOMORROW AND BECOME WIDESPREAD BY
THE AFTERNOON.


&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

SON

000
FXUS64 KOHX 212006
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
306 PM CDT TUE MAY 21 2013

.DISCUSSION...

...STRONG TO SEVERE STORMS POSSIBLE ON AND OFF THROUGH WEDNESDAY
AFTERNOON-EVENING...

CURRENTLY...AN AREA OF SHOWERS AND STORMS OVER EASTERN MIDDLE TN
CONTINUES TO PRODUCE TORRENTIAL RAINFALL AND MARGINALLY SEVERE
HAIL OR JUST UNDER SEVERE LIMITS...AS WELL AS ISOLATED DAMAGING
WIND GUSTS. THE STORM PREDICTION CENTER HAS ISSUED A SEVERE
T-STORM WATCH OVER OUR FIVE FAR EASTERN COUNTIES UNTIL 02Z...BUT
WE WILL BE ABLE TO CANCEL THAT WELL BEFORE THEN. STRONG TO
POSSIBLY SEVERE CELLS WILL CONTINUE THERE FOR THE NEXT 1-2 HOURS.

ANOTHER LINE OF STRONG STORMS IS CURRENTLY OVER ARKANSAS AND THIS
WILL PUSH EAST INTO MIDDLE TN MOSTLY LIKELY WELL AFTER 00Z. A FEW
ISOLATED STORMS STREAMING NORTH AHEAD OF THIS SECOND LINE THOUGH
COULD SQUEAK INTO SOUTHWEST MIDDLE TN AND BE CAPABLE OF PRODUCING
STRONG WINDS/HAIL THIS AFTERNOON-EVENING. SO FOR THE REST OF
TODAY...THE FOCUS ON SEVERE WEATHER WILL SHIFT FROM OUR FAR EAST
TO OUR SOUTHWEST THROUGH 7PM-ISH.

TONIGHT...THE LINE OF CONVECTION PUSHING OUT OF ARKANSAS WILL
LIKELY BE OVERTAKEN BY CONVECTION IN EASTERN OK. THE SOUTHERN
PORTION OF THE LINE WILL LIKELY TAKE OVER AS WE HAVE STABILIZED
FROM TODAY`S CONVECTION. THUS...WOULD NOT BE SURPRISED TO SEE THIS
LINE APPROACH MIDDLE TN LATE TONIGHT-EARLY WEDNESDAY MORNING AND
WEAKEN CONSIDERABLY IF NOT DISSIPATE COMPLETELY. EITHER OCCURRENCE
WILL YIELD ANOTHER CHANCE TO DESTABILIZE AHEAD OF THE UPPER LEVEL
LOW...WITH MORE STRONG TO SEVERE STORMS POSSIBLE WEDNESDAY LATE
MORNING BUT ESPECIALLY IN THE AFTERNOON. WE`LL HAVE BETTER SHEAR
IN PLACE AS WELL...WITH THE BEST CHANCE OF SEVERE ALONG AND EAST
OF I-65. SPC PLACED US IN A DAY TWO SLIGHT RISK...AGAIN WITH THE
MAIN THREATS BEING DAMAGING WINDS AND LARGE HAIL. ALTHOUGH THE SFC
BOUNDARY WILL PUSH EAST OF THE AREA WEDNESDAY NIGHT...MORE SHOWERS
AND STORMS (LIKELY NON-SEVERE) WILL ACCOMPANY THE TRAILING UPPER
LOW THROUGH THURSDAY AND WE WILL FINALLY DRY OUT THURSDAY NIGHT
WEST TO EAST.

THEREAFTER...LOTS OF QUESTION WHETHER OR NOT WE DRY OUT AND RIDGE
OUT VIA THE GFS...OR THE WARM FRONT FROM A PLAINS LOW EXTENDS
EASTWARD INTO MIDDLE TN...KEEPING CHANCES OF RAIN ACROSS THE AREA
OVER THE WEEKEND INTO EARLY NEXT WEEK. FOR NOW HAVE SLIGHT CHC
POPS OVER THE NE SUNDAY NIGHT-MONDAY. FOR TEMPS...WENT WITH LOWER-
THAN-MEX IN CASE EURO PANS OUT.

&&

.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE      68  83  62  78 /  50  60  30  20
CLARKSVILLE    67  80  59  76 /  80  60  20  20
CROSSVILLE     64  82  60  75 /  50  70  50  30
COLUMBIA       68  83  62  81 /  50  60  30  20
LAWRENCEBURG   67  82  61  82 /  60  60  30  20
WAVERLY        68  81  60  78 /  80  60  20  20

&&

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

$$

AL

000
FXUS64 KMEG 212004
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
304 PM CDT TUE MAY 21 2013

.DISCUSSION...
VERY ACTIVE RADAR THIS AFTERNOON. OVERNIGHT/EARLY MORNING
CONVECTION MAY HAVE US FROM A MUCH MORE SIGNIFICANT SEVERE
WEATHER OUTBREAK TODAY...ALTHOUGH SEVERE POTENTIAL STILL
EXISTS...ESPECIALLY ACROSS NORTH MISSISSIPPI. FARTHER NORTH THE
AIRMASS HAS BEEN WORKED OVER...AND ABUNDANT CLOUD COVER HAS KEPT
TEMPERATURES QUITE A BIT COOLER. INSTABILITY IS HIGHEST IN NORTH
MISSISSIPPI WHERE TEMPERATURES HAVE BEEN ABLE TO CLIMB INTO THE
MIDDLE AND UPPER 80S. DEW POINTS ARE IN THE UPPER 60S TO LOWER 70S
RESULTING IN CAPES IN EXCESS OF 2500 J/KG AND LI`S BELOW -6C. JUST
ACROSS THE STATE LINE IN MOST OF TN...THE MISSOURI BOOTHEEL AND
NORTHEAST ARKANSAS...CAPES ARE GENERALLY BELOW 1500 J/KG WITH LI`S
-4C OR GREATER. DEW POINTS ARE ALSO SLIGHTLY HIGHER. IN THE PAST
COUPLE OF HOURS STORMS HAVE DEVELOPED IN NORTH MISSISSIPPI AND
HAVE SHOWN SOME SIGNS OF ROTATION. 0-3KM HELICITY IS GENERALLY
50-90M^2/S^2 WHICH WOULD CERTAINLY SUPPORT ROTATING STORMS. UPPER
LEVEL SUPPORT IS NOT CURRENTLY AS FAVORABLE FOR SEVERE
THUNDERSTORMS...ALTHOUGH BETTER SUPPORT IS EXPECTED TO MOVE IN
TONIGHT.

ANOTHER ROUND OF STORMS CAN BE SEEN OVER NORTH TEXAS INTO
OKLAHOMA. THIS LINE WILL BRING ADDITIONAL SHOWERS AND
THUNDERSTORMS TO THE MIDSOUTH OVERNIGHT. NUMEROUS OUTFLOW
BOUNDARIES WILL ONLY HELP SUPPORT FOCUS UPDRAFTS AND MAINTAIN A
SEVERE THREAT.

A SHORTWAVE TROUGH CURRENTLY OVER THE TEXAS AND OKLAHOMA
PANHANDLES WILL SHIFT TO THE EAST THIS EVENING AND APPROACH THE
MISSISSIPPI RIVER BY SUNRISE. A SURFACE LOW HAS DEVELOPED OVER
NORTH TEXAS AND SHOULD TRACK NORTHEAST ACROSS CENTRAL ARKANSAS
DURING THE NIGHT. WE WILL SEE A 40-45KT LLJ DEVELOP BY MIDNIGHT
AND MUCH OF THE MIDSOUTH WILL BE IN THE RIGHT ENTRANCE REGION OF A
70-80KT UPPER LEVEL JET. THIS ADDITIONAL DYNAMIC SUPPORT WILL MOVE
IN JUST AS WE LOSE DAYTIME THERMODYNAMIC SUPPORT. THUS FEEL LIKE
THE THREAT FOR SEVERE WEATHER WILL REMAIN ABOUT THE SAME DURING
THE NIGHT...MARGINAL BUT CERTAINLY NOT ZERO.

RESEARCHERS AT MISSISSIPPI STATE UNIVERSITY LAUNCHED A WEATHER
BALLOON MIDDAY ABOUT 30 MILES SOUTHWEST OF GREENWOOD MISSISSIPPI.
IT SHOWS A BIT OF A CAP AT 10KFT...BUT CAPE IN EXCESS OF 3500
J/KG. FARTHER NORTH AT LITTLE ROCK A MIDDAY SOUNDING WAS
INDICATIVE OF A WORKED OVER ENVIRONMENT...FEATURING ONLY 343
JOULES OF CAPE. ANY THREATS FROM STORMS IN WEST TENNESSEE AND EAST
ARKANSAS WOULD BE PRIMARILY HAIL.

A COLD FRONT WILL SWEEP ACROSS THE MIDSOUTH TOMORROW BRINGING AN
END TO THE PRECIPITATION. THE FRONT SHOULD MOVE INTO EAST ARKANSAS
BY 10 AM...CROSS THE MISSISSIPPI RIVER MIDDAY AND EXIT INTO
CENTRAL TENNESSEE/NORTH ALABAMA DURING THE MID AFTERNOON HOURS.
RAIN WILL LIKELY LIMIT TEMPERATURES AGAIN TOMORROW BUT AS RAIN
ENDS...WE COULD SEE TEMPERATURES SURGE INTO THE LOW 80S DURING THE
AFTERNOON HOURS. THE DIURNAL TEMPERATURE PROFILE WILL LIKELY BE
TRICKY TOMORROW DUE THE RAINFALL AND FRONT.

THURSDAY THROUGH THE WEEKEND LOOK MOSTLY DRY. TEMPERATURES THURSDAY
WILL BE NEAR NORMAL...WITH COOLISH FRIDAY...THEN TRENDING
GRADUALLY WARMER THROUGH THE WEEKEND. FRIDAY THROUGH THE WEEKEND
OUR WEATHER SHOULD BE PRIMARILY INFLUENCED BY A WEAK RIDGE ALOFT
AND SURFACE HIGH PRESSURE RESULTING IN DRY CONDITIONS.

&&

.AVIATION...
18Z TAF CYCLE

COMPLEX WEATHER PATTERN FOR THIS AFTERNOON AND EVENING. ONGOING
CONVECTION..MAINLY OVER NORTH MISSISSIPPI AT THIS TIME..WILL
CONTINUE TO DEVELOP AND BRIEFLY AFFECT TERMINALS THIS AFTERNOON.
WINDS OUT OF THE SOUTH AT AROUND 10KTS ARE EXPECTED AT ALL SITES
THIS AFTERNOON...WITH SOME BRIEF GUSTY WINDS GENERATED BY NEARBY
TS. OVERNIGHT..EXPECT THUNDERSTORMS TO INCREASE IN COVERAGE AND
MOVE FROM WEST TO EAST WITH STRONG WIND GUSTS TO 20KT POSSIBLE.
THUNDERSTORMS WILL MOVE EAST OF THE MIDSOUTH BETWEEN 10-12UTC
WITH ADDITIONAL SHOWERS EXPECTED THROUGH THE MORNING.

SAK

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  69  83  61  82 /  80  60  10  10
MKL  67  81  58  81 /  70  60  10  10
JBR  65  82  57  80 /  90  40  10  10
TUP  67  83  60  86 /  70  70  10  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMRX 211857
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
256 PM EDT TUE MAY 21 2013

.SHORT TERM (TONIGHT AND WEDNESDAY)...ONGOING CONVECTION ACROSS
MIDDLE TN WILL MOVE INTO THE MRX CWA LATE THIS AFTERNOON/EVENING.
BEHIND THIS LINE...A FEW SHOWERS/THUNDERSTORMS MAY LINGER ACROSS THE
AREA INTO THE OVERNIGHT HOURS...BUT MOST LOCATIONS SHOULD STAY DRY.
ANOTHER BAND OF CONVECTION WILL DEVELOP ALONG AN APPROACHING COLD
FRONT AND MOVE THROUGH ON WEDNESDAY.  THIS WILL SPREAD A LARGE BAND
OF THUNDERSTORMS INTO THE AREA AS EARLY AS LATE WEDNESDAY
AFTERNOON.  WITH THE WARM...MOIST AND WEAK TO MODERATELY UNSTABLE
AIR MASS IN PLACE...SOME OF THESE STORMS MAY BECOME
STRONG...POSSIBLY SEVERE.

.LONG TERM (WEDNESDAY NIGHT THROUGH TUESDAY)...BEST RAIN CHANCES
WILL BE WEDNESDAY NIGHT INTO THURSDAY AHEAD OF THE COLD FRONT. MOS
POPS TRENDING LIKELY NOW FOR WEDNESDAY NIGHT WITH PREVIOUS GRIDS
LOOKING ON TRACK. SHORTWAVE DROPPING SE ACROSS THE OHIO RIVER VALLEY
INTO THE CENTRAL APPALACHIANS ON FRIDAY PLUS DAYTIME HEATING...SO
WILL CONTINUE THE SLIGHT CHANCE POPS FOR MAINLY SW VA/NE TN AREAS
EARLY FRIDAY.

SURFACE AND UPPER RIDGE SHOULD PROVIDE DRY WEATHER FOR SATURDAY INTO
SUNDAY...ALTHOUGH WARM FRONT AND NW FLOW ALOFT DEVELOPING ON SUNDAY
WILL NEED TO BE WATCHED. KEPT SUNDAY DRY LEADING INTO SLIGHT CHANCE
POPS BY SUNDAY NIGHT INTO MONDAY. INTRODUCED TUESDAY WITH DIURNAL
CONVECTION OVER FAVORED AREAS OF SW VA AND NE TN...ALTHO JUST SLIGHT
CHANCE POPS AT THIS TIME.

FOR TEMPS...BOTH 21/00Z AND 21/12Z GFSX MOS TEMPS ARE TRENDING
COOLER BEHIND THE COLD FRONTAL PASSAGE LATE THURSDAY. NUDGED TEMPS
DOWN A BIT FROM PREVIOUS GRIDS...ESPECIALLY MINS UNTIL SOME
SOUTHERLY LOW LEVEL FLOW RETURNS BY MONDAY NIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN  66  84  63  81  57 /  20  60  50  30  20
KNOXVILLE AIRPORT, TN    65  84  62  80  56 /  30  60  50  40  30
OAK RIDGE, TN            65  84  62  81  56 /  30  60  50  40  30
TRI CITIES AIRPORT, TN   61  83  61  79  55 /  40  50  50  50  40

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

MJB/TG

000
FXUS64 KMEG 211807
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
107 PM CDT TUE MAY 21 2013

.UPDATE...

.UPDATED FOR 18Z TAF DISCUSSION..


&&

.PREV DISCUSSION... /ISSUED 1059 AM CDT TUE MAY 21 2013/

UPDATE...MORNING UPDATE.

ADJUSTED THE FORECAST BASED ON RADAR AND SATELLITE TRENDS. DOES
NOT LOOK LIKE WE WILL REALIZE THE EXPECTED AFTERNOON HIGH
TEMPERATURES DUE TO CLOUD COVER AND ONGOING PRECIPITATION. THE
EXCEPTION MAY BE IN NORTH MISSISSIPPI WHERE RAIN IS LESS
WIDESPREAD. HOWEVER CLOUD COVER IS STILL WIDESPREAD. NEW ZONES ARE
OUT. WILL LIKELY FOCUS ON SEVERE WEATHER THREAT THIS AFTERNOON. DO
NOT ANTICIPATE SIGNIFICANT CHANGES TO THE LONG TERM WITH THE
AFTERNOON PACKAGE.

PREV DISCUSSION... /ISSUED 735 AM CDT TUE MAY 21 2013/

UPDATE...

UPDATED FOR 12Z AVIATION DISCUSSION.

PREV DISCUSSION... /ISSUED 551 AM CDT TUE MAY 21 2013/

DISCUSSION...09Z SURFACE ANALYSIS PLACES A SURFACE LOW OVER
EASTERN SOUTH DAKOTA WITH A COLD FRONT EXTENDING SOUTH FROM THE
LOW ACROSS WESTERN MISSOURI...THEN BACK INTO CENTRAL OKLAHOMA AND
BACK INTO TEXAS. MEANWHILE...SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH LAST NIGHT/S CONVECTIVE ACTIVITY OVER THE PLAINS AND WESTERN
SECTIONS OF THE LOWER MISSISSIPPI VALLEY PRODUCED DAMAGING WINDS
ACROSS PORTIONS OF EAST AND NORTHEAST ARKANSAS AND WEAKENED AS IT
MOVED EAST OF THE MISSISSIPPI RIVER. TEMPERATURES AS OF 4 AM CDT
ARE PREDOMINANTLY IN THE 60S AT MOST LOCATIONS. SEVERE
THUNDERSTORM POTENTIAL MAINLY LATER THIS AFTERNOON INTO TONIGHT
REMAINS THE MAIN FORECAST CONCERN IN THIS MORNING/S FORECAST
ISSUANCE.

SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH LAST NIGHTS CONVECTION HAS MOVED TO
PORTIONS OF WEST TENNESSEE NEAR THE MISSISSIPPI RIVER. REGIONAL
WSR-88D RADAR TRENDS SHOW A COUPLE OF ADDITIONAL LINES ACROSS
ARKANSAS...THE FIRST LINE ACROSS EAST AND NORTHEAST ARKANSAS...AND
A SECOND LINE BEGINNING TO APPROACH CENTRAL ARKANSAS. LATEST RADAR
TRENDS INDICATE LESS SURFACE BASED INSTABILITY ACROSS THE AREA AND
THESE TWO ADDITIONAL LINES ARE EXPECTED TO BE REMAIN ELEVATED AT
THIS TIME.

A SURFACE LOW NEAR MIDLAND TEXAS EARLY THIS MORNING WILL MOVE
INTO EASTERN OKLAHOMA BY LATE AFTERNOON...INTO NORTHWEST ARKANSAS
TONIGHT AND UP INTO THE OHIO RIVER VALLEY BY WEDNESDAY.
MEANWHILE...AN UPPER LEVEL TROUGH WILL BECOME NEGATIVELY TILTED
AS IT MOVES INTO THE MIDDLE AND LOWER MISSISSIPPI VALLEYS TONIGHT.
THE ATMOSPHERE IS EXPECTED TO RECOVER AND DESTABILIZE ONCE AGAIN
BY THIS AFTERNOON INTO TONIGHT. MODERATELY STEEP TO STEEP 700-500
MB LAYER MID LEVEL LAPSE RATES...0-6 KM BULK SHEAR VALUES BETWEEN
40 TO 50 KTS...SURFACE BASED CAPE VALUES BETWEEN 1500-2500 J/KG
ESPECIALLY DURING THE LATE AFTERNOON INTO THE EARLY
EVENING...NEARLY UNIDIRECTIONAL WINDS ALOFT...AND FAVORABLE UPPER
LEVEL DIVERGENCE PRODUCED BY THE LEFT EXIT REGION OF AN UPPER
LEVEL JET STREAK SUGGEST THE CONVECTIVE ACTIVITY WILL BE MOSTLY IN
THE FORM OF A LINE AS IT MOVES ACROSS THE MID SOUTH TONIGHT. THE
PRIMARY SEVERE WEATHER THREATS WILL BE LARGE HAIL AND DAMAGING
WINDS WITH ANY THUNDERSTORMS THAT REACH SEVERE LIMITS. A POTENTIAL
WILL ALSO EXIST FOR PERHAPS A TORNADO OR TWO EMBEDDED WITHIN THE
LINE AS IT MOVES ACROSS THE AREA. LOCALIZED FLASH FLOODING FROM
HEAVY RAINFALL WILL BE POSSIBLE AS PRECIPITABLE WATER VALUES WILL
RANGE FROM 1.5 TO 2 INCHES. WILL CONTINUE TO MONITOR TRENDS AND
CONSIDER THE POTENTIAL FOR A FLASH FLOOD WATCH MAINLY WEST OF THE
MISSISSIPPI RIVER TODAY AND TONIGHT IF SHORT TERM TRENDS SHOW AN
INCREASING POTENTIAL. WILL HIGHLIGHT SEVERE WEATHER THREATS IN THE
HAZARDOUS WEATHER OUTLOOK.

CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO WEDNESDAY
AS THE COLD FRONT MOVES THROUGH THE MID SOUTH AND GRADUALLY TAPER
OFF INTO WEDNESDAY NIGHT.

LONG TERM...(THURSDAY THROUGH MEMORIAL DAY)...LATEST LONG TERM
MODEL TRENDS INDICATE ANOTHER FRONT WILL MOVE THROUGH THE LOWER
MISSISSIPPI VALLEY THURSDAY. A POTENTIAL WILL EXIST FOR ADDITIONAL
SHOWERS AND THUNDERSTORMS TO DEVELOP BUT OVERALL CONFIDENCE IN
COVERAGE REMAINS LOW. HIGH PRESSURE IS EXPECTED TO BUILD INTO THE
MID SOUTH FOR THURSDAY NIGHT INTO FRIDAY WITH SLIGHTLY COOLER AIR
TEMPORARILY RETURNING BACK TO THE FORECAST AREA. LONG TERM MODELS
REMAIN IN DISAGREEMENT WITH THE OVERALL SYNOPTIC PATTERN AS THE
COLD FRONT RETURNS NORTH AS A WARM FRONT THIS WEEKEND INTO EARLY
NEXT WEEK. THE GFS REMAINS THE DRIER OF THE SOLUTIONS WITH THE
ECMWF SUGGESTING SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS
ESPECIALLY ALONG AND NORTH OF I-40 FOR THIS WEEKEND INTO MEMORIAL
DAY. HAVE OPTED TO LEAVE POPS OUT OF THE FORECAST UNTIL MODELS
COME INTO BETTER CONSENSUS.

CJC

.AVIATION...
18Z TAF CYCLE

COMPLEX WEATHER PATTERN FOR THIS AFTERNOON AND EVENING. ONGOING
CONVECTION..MAINLY OVER NORTH MISSISSIPPI AT THIS TIME..WILL
CONTINUE TO DEVELOP AND BRIEFLY AFFECT TERMINALS THIS AFTERNOON.
WINDS OUT OF THE SOUTH AT AROUND 10KTS ARE EXPECTED AT ALL SITES
THIS AFTERNOON...WITH SOME BRIEF GUSTY WINDS GENERATED BY NEARBY
TS. OVERNIGHT..EXPECT THUNDERSTORMS TO INCREASE IN COVERAGE AND
MOVE FROM WEST TO EAST WITH STRONG WIND GUSTS TO 20KT POSSIBLE.
THUNDERSTORMS WILL MOVE EAST OF THE MIDSOUTH BETWEEN 10-12UTC
WITH ADDITIONAL SHOWERS EXPECTED THROUGH THE MORNING.

SAK

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  70  84  65  82 /  80  50  10  20
MKL  68  82  63  81 /  70  50  10  20
JBR  66  82  62  82 /  90  30  10  20
TUP  68  83  65  86 /  60  60  10  20

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KOHX 211806
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
106 PM CDT TUE MAY 21 2013

.MESOSCALE UPDATE...

STRONG GUST FRONT EJECTING OUT EAST OF A LINE OF SHOWERS AND
STORMS NEAR THE I-65 CORRIDOR HAS PRODUCED WINDS OVER 50 MPH AND
MULTIPLE TREES...POWERLINES AND BRANCHES DOWN...MANY IN AND AROUND
THE NASHVILLE METRO AREA. STRONG TO SEVERE WINDS WILL CONTINUE
ALONG THE GUST FRONT WHICH IS NEAR WESTMORELAND DOWN TO LEBANON
DOWN TO LEWISBURG. STORMS ON EITHER SIDE OF THIS BOUNDARY WILL BE
CAPABLE OF PRODUCING HAIL UP TO THE SIZE OF QUARTERS AND WINDS UP
TO 60 MPH.

WILL EXPECT THESE THREATS TO CONTINUE WELL EAST OF I-65 AS
UNSTABLE CONDITIONS REMAIN OVER ALL OF MIDDLE TN.

&&

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

$$

AL

000
FXUS64 KMRX 211725
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
125 PM EDT TUE MAY 21 2013

.AVIATION...SCT THUNDERSTORMS ARE EXPECTED ACROSS THE SOUTHERN
APPALACHIAN REGION THIS AFTERNOON/EVENING AS A LINE OF CONVECTION
AHEAD OF A COLD FRONT WELL TO OUR WEST WORKS ITS WAY EASTWARD INTO
THE MRX CWA.  WITH A MOIST AND MODERATELY UNSTABLE AIR MASS IN PLACE
...SOME OF THESE STORMS MAY BECOME STRONG TO SEVERE WITH THE MAIN
THREAT BEING DAMAGING WINDS AND HAIL.  OVERNIGHT...ANY LINGERING
STORMS WILL PULL AWAY FROM THE AREA AND PATCHY FOG SHOULD DEVELOP ONCE
AGAIN TONIGHT.  AREAS OF MVFR CONDITIONS AND LOCALLY IFR CONDITIONS
ARE POSSIBLE...ESPECIALLY NEAR TRI.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

MJB

000
FXUS64 KMRX 211600
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1200 PM EDT TUE MAY 21 2013

.DISCUSSION...FOG HAS LIFTED ACROSS THE AREA THIS MORNING.
SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THE SOUTHERN APPALACHIAN
REGION THIS AFTERNOON/EVENING AS A LINE OF CONVECTION AHEAD OF A
COLD FRONT WELL TO OUR WEST WORKS ITS WAY EASTWARD INTO THE MRX
CWA.  WITH A MOIST AND MODERATELY UNSTABLE AIR MASS IN PLACE...SOME
OF THESE STORMS MAY BECOME STRONG TO SEVERE WITH THE MAIN THREAT
BEING DAMAGING WINDS AND HAIL.  WILL UPDATE ZONE PACKAGE TO REMOVE
MORNING FOG.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN  88  65  85  63  84 /  30  30  60  50  30
KNOXVILLE AIRPORT, TN    87  65  84  63  81 /  30  30  50  50  40
OAK RIDGE, TN            87  65  84  62  80 /  30  20  50  50  40
TRI CITIES AIRPORT, TN   85  59  84  59  77 /  20  20  60  50  50

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

MJB

000
FXUS64 KMEG 211559
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1059 AM CDT TUE MAY 21 2013

.UPDATE...MORNING UPDATE.

ADJUSTED THE FORECAST BASED ON RADAR AND SATELLITE TRENDS. DOES
NOT LOOK LIKE WE WILL REALIZE THE EXPECTED AFTERNOON HIGH
TEMPERATURES DUE TO CLOUD COVER AND ONGOING PRECIPITATION. THE
EXCEPTION MAY BE IN NORTH MISSISSIPPI WHERE RAIN IS LESS
WIDESPREAD. HOWEVER CLOUD COVER IS STILL WIDESPREAD. NEW ZONES ARE
OUT. WILL LIKELY FOCUS ON SEVERE WEATHER THREAT THIS AFTERNOON. DO
NOT ANTICIPATE SIGNIFICANT CHANGES TO THE LONG TERM WITH THE
AFTERNOON PACKAGE.


&&

.PREV DISCUSSION... /ISSUED 735 AM CDT TUE MAY 21 2013/

UPDATE...

UPDATED FOR 12Z AVIATION DISCUSSION.

PREV DISCUSSION... /ISSUED 551 AM CDT TUE MAY 21 2013/

DISCUSSION...09Z SURFACE ANALYSIS PLACES A SURFACE LOW OVER
EASTERN SOUTH DAKOTA WITH A COLD FRONT EXTENDING SOUTH FROM THE
LOW ACROSS WESTERN MISSOURI...THEN BACK INTO CENTRAL OKLAHOMA AND
BACK INTO TEXAS. MEANWHILE...SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH LAST NIGHT/S CONVECTIVE ACTIVITY OVER THE PLAINS AND WESTERN
SECTIONS OF THE LOWER MISSISSIPPI VALLEY PRODUCED DAMAGING WINDS
ACROSS PORTIONS OF EAST AND NORTHEAST ARKANSAS AND WEAKENED AS IT
MOVED EAST OF THE MISSISSIPPI RIVER. TEMPERATURES AS OF 4 AM CDT
ARE PREDOMINANTLY IN THE 60S AT MOST LOCATIONS. SEVERE
THUNDERSTORM POTENTIAL MAINLY LATER THIS AFTERNOON INTO TONIGHT
REMAINS THE MAIN FORECAST CONCERN IN THIS MORNING/S FORECAST
ISSUANCE.

SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH LAST NIGHTS CONVECTION HAS MOVED TO
PORTIONS OF WEST TENNESSEE NEAR THE MISSISSIPPI RIVER. REGIONAL
WSR-88D RADAR TRENDS SHOW A COUPLE OF ADDITIONAL LINES ACROSS
ARKANSAS...THE FIRST LINE ACROSS EAST AND NORTHEAST ARKANSAS...AND
A SECOND LINE BEGINNING TO APPROACH CENTRAL ARKANSAS. LATEST RADAR
TRENDS INDICATE LESS SURFACE BASED INSTABILITY ACROSS THE AREA AND
THESE TWO ADDITIONAL LINES ARE EXPECTED TO BE REMAIN ELEVATED AT
THIS TIME.

A SURFACE LOW NEAR MIDLAND TEXAS EARLY THIS MORNING WILL MOVE
INTO EASTERN OKLAHOMA BY LATE AFTERNOON...INTO NORTHWEST ARKANSAS
TONIGHT AND UP INTO THE OHIO RIVER VALLEY BY WEDNESDAY.
MEANWHILE...AN UPPER LEVEL TROUGH WILL BECOME NEGATIVELY TILTED
AS IT MOVES INTO THE MIDDLE AND LOWER MISSISSIPPI VALLEYS TONIGHT.
THE ATMOSPHERE IS EXPECTED TO RECOVER AND DESTABILIZE ONCE AGAIN
BY THIS AFTERNOON INTO TONIGHT. MODERATELY STEEP TO STEEP 700-500
MB LAYER MID LEVEL LAPSE RATES...0-6 KM BULK SHEAR VALUES BETWEEN
40 TO 50 KTS...SURFACE BASED CAPE VALUES BETWEEN 1500-2500 J/KG
ESPECIALLY DURING THE LATE AFTERNOON INTO THE EARLY
EVENING...NEARLY UNIDIRECTIONAL WINDS ALOFT...AND FAVORABLE UPPER
LEVEL DIVERGENCE PRODUCED BY THE LEFT EXIT REGION OF AN UPPER
LEVEL JET STREAK SUGGEST THE CONVECTIVE ACTIVITY WILL BE MOSTLY IN
THE FORM OF A LINE AS IT MOVES ACROSS THE MID SOUTH TONIGHT. THE
PRIMARY SEVERE WEATHER THREATS WILL BE LARGE HAIL AND DAMAGING
WINDS WITH ANY THUNDERSTORMS THAT REACH SEVERE LIMITS. A POTENTIAL
WILL ALSO EXIST FOR PERHAPS A TORNADO OR TWO EMBEDDED WITHIN THE
LINE AS IT MOVES ACROSS THE AREA. LOCALIZED FLASH FLOODING FROM
HEAVY RAINFALL WILL BE POSSIBLE AS PRECIPITABLE WATER VALUES WILL
RANGE FROM 1.5 TO 2 INCHES. WILL CONTINUE TO MONITOR TRENDS AND
CONSIDER THE POTENTIAL FOR A FLASH FLOOD WATCH MAINLY WEST OF THE
MISSISSIPPI RIVER TODAY AND TONIGHT IF SHORT TERM TRENDS SHOW AN
INCREASING POTENTIAL. WILL HIGHLIGHT SEVERE WEATHER THREATS IN THE
HAZARDOUS WEATHER OUTLOOK.

CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO WEDNESDAY
AS THE COLD FRONT MOVES THROUGH THE MID SOUTH AND GRADUALLY TAPER
OFF INTO WEDNESDAY NIGHT.

LONG TERM...(THURSDAY THROUGH MEMORIAL DAY)...LATEST LONG TERM
MODEL TRENDS INDICATE ANOTHER FRONT WILL MOVE THROUGH THE LOWER
MISSISSIPPI VALLEY THURSDAY. A POTENTIAL WILL EXIST FOR ADDITIONAL
SHOWERS AND THUNDERSTORMS TO DEVELOP BUT OVERALL CONFIDENCE IN
COVERAGE REMAINS LOW. HIGH PRESSURE IS EXPECTED TO BUILD INTO THE
MID SOUTH FOR THURSDAY NIGHT INTO FRIDAY WITH SLIGHTLY COOLER AIR
TEMPORARILY RETURNING BACK TO THE FORECAST AREA. LONG TERM MODELS
REMAIN IN DISAGREEMENT WITH THE OVERALL SYNOPTIC PATTERN AS THE
COLD FRONT RETURNS NORTH AS A WARM FRONT THIS WEEKEND INTO EARLY
NEXT WEEK. THE GFS REMAINS THE DRIER OF THE SOLUTIONS WITH THE
ECMWF SUGGESTING SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS
ESPECIALLY ALONG AND NORTH OF I-40 FOR THIS WEEKEND INTO MEMORIAL
DAY. HAVE OPTED TO LEAVE POPS OUT OF THE FORECAST UNTIL MODELS
COME INTO BETTER CONSENSUS.

CJC

AVIATION...
12Z TAF CYCLE

A COUPLE LINES OF THUNDERSTORMS WILL MOVE THROUGH THE REGION THIS
MORNING. ALL TAF SITES WILL REMAIN VFR THROUGHOUT MOST OF THE DAY
WITH THE EXCEPTION OF SOME TEMPO MVFR CIGS AT SITES MEM AND MKL.
MORE STORMS WILL DEVELOP LATER THIS AFTERNOON...SOME OF WHICH MAY
BECOME SEVERE AND WILL MOST LIKELY BE IN THE FORM OF A LINE...WITH
HEAVY RAIN TEMPORARILY AFFECTING VISBYS. SOME LLWS COULD ALSO BE
POSSIBLE THIS EVENING AS THE LLJ INCREASES.

VARIABLE WINDS THIS MORNING...DUE TO TEMPORARY WINDSHIFTS
ASSOICATED WITH THESE LINES OF STORMS MOVING THROUGH. WINDS WILL
INCREASE AND BECOME MORE SOUTHERLY AROUND 12-14 KTS WITH HIGHER GUSTS
16-24 KTS BY MID AFTN.

AC3

&&

.AVIATION...


&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  77  70  84  65 /  60  80  50  10
MKL  76  68  82  63 /  60  70  50  10
JBR  74  66  82  62 /  80  90  30  10
TUP  86  68  83  65 /  30  60  60  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KOHX 211512
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1012 AM CDT TUE MAY 21 2013

.UPDATE...
UPPER LOW SPINNING OVER THE TX PANHANDLE WILL BE THE MAIN WEATHER
MAKER ACROSS THE SOUTHERN CONUS TODAY...INCLUDING MIDDLE TN.
DOWNSTREAM OF THIS UPPER LOW IS A BOUNDARY LIT UP WITH CONVECTION
FROM SRN OK TO WRN TN. THESE CONVECTIVE COMPLEXES WILL CONTINUE TO
PUSH EAST-NORTHEAST BUT THEY SHOULD WEAKEN DUE TO DECENT WARMING
ALOFT ACROSS MIDDLE TN. NOT EXPECTING ANY TYPE OF SEVERE WEATHER
CHANCES UNTIL AT LEAST THIS AFTERNOON.

SPEAKING OF THIS AFTERNOON...PROGGED SOUNDINGS ACROSS SOUTHERN
MIDDLE TN INDICATE QUITE A BIT OF INSTABILITY. HOWEVER...WINDS ARE
STILL VERY WEAK AND WITH A OVERLY-MOIST SOUNDING...ANY STORM THAT
DEVELOPS THIS AFTERNOON WOULD LIKELY BE OF THE PULSE NATURE WITH
TORRENTIAL RAINFALL AND POSSIBLY ISOLATED DAMAGING WINDS. THE
BIGGER SEVERE WEATHER THREAT WILL COME OVERNIGHT INTO WEDNESDAY
MORNING...WHERE STORMS WILL DEVELOP THIS AFTERNOON ACROSS THE SRN
PLAINS AND PUSH EAST QUICKLY OVERNIGHT. THE LOW-LEVEL JET WILL
KICK INTO GEAR BETWEEN 6-12Z...AND ANY STORMS NEARING THE TN RIVER
AT THAT TIME WILL PROVIDE THE BEST CHANCE FOR SEVERE STORMS...WITH
DAMAGING WINDS BEING THE MAIN THREAT. REALLY THINK THAT HEAVY
RAINFALL AND ISOLATED DAMAGING WINDS ARE OUR BIGGEST CONCERNS
THROUGH 18Z TOMORROW...AND STORMS TOWARDS THE DAWN HOUR COULD
PROVIDE AN ADDED ISOLATED HAIL THREAT AS WELL. AT THIS TIME...THE
TORNADO THREAT SEEMS MINIMAL BUT WE CANNOT RULE IT OUT TOWARDS
MORNING WITH THE STRONGEST SHEAR IN PLACE.

FOR THE SHORT TERM...LOWERED POPS OVER ERN MIDDLE TN AND INCREASED
TEMPS EVERYWHERE...JUST A COUPLE DEGREES OVER THE WEST WHERE
CONVECTION WILL OCCUR MIDDAY-EARLY AFTERNOON. UPDATE ALREADY SENT
TO WEB. ZONE UPDATE COMING SHORTLY.

&&

.PREV DISCUSSION... /ISSUED 321 AM CDT TUE MAY 21 2013/

SHORT TERM...

RADAR IMAGERY THIS MORNING SHOWS AN EXTENSIVE LINE OF SHOWERS AND
THUNDERSTORMS FROM THE GREAT LAKES SOUTHWARD INTO WESTERN
TENNESSEE...WITH ACTIVITY NOW APPROACHING OUR WESTERN CWA BORDER.
ALTHOUGH MCS HAS SHOWN AN OVERALL WEAKENING TREND...SATELLITE
IMAGERY SHOWS NEW UPDRAFTS DEVELOPING ALONG LEADING EDGE OF COLD
POOL WITH CLOUD TOPS COOLING. LATEST SHORT TERM MODEL GUIDANCE
SUCH AS THE 4 KM WRF...HRRR...AND NSSL WRF ALL BRING ACTIVITY INTO
OUR WESTERN ZONES IN A FEW HOURS BEFORE DIMINISHING LATER THIS
MORNING...AND THUS WILL RAISE POPS SUBSTANTIALLY OVER GUIDANCE FOR
THE PRE-FIRST AND FIRST PERIOD OF THE FORECAST. ALSO BUMPED UP
CLOUD COVER AND WENT SIGNIFICANTLY BELOW MOS GUIDANCE HIGHS FOR
TODAY DUE TO ANTICIPATED CLOUDS/PRECIP. NO SEVERE WEATHER IS
EXPECTED WITH THESE STORMS THIS MORNING ALTHOUGH SOME GUSTY WINDS
MAY OCCUR. CHANGES TO THE FORECAST ARE LIKELY DEPENDING ON HOW
CURRENT ACTIVITY EVOLVES.

MODELS INDICATE A SHARP SHORTWAVE TROUGH CURRENTLY SEEN ON WATER
VAPOR IMAGERY OVER NEW MEXICO WILL SWING THROUGH THE SOUTHERN
PLAINS TODAY...THEN ACROSS THE OHIO VALLEY AND NORTHWEST PART OF
OUR FORECAST AREA TUESDAY NIGHT. EXPECTING NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON...THEN SPREAD INTO WESTERN TENNESSEE AND THE NORTHWEST
MID STATE TUESDAY EVENING AND ESPECIALLY AFTER MIDNIGHT TUESDAY
NIGHT. SPC HAS THE NORTHWEST PART OF THE FORECAST AREA IN A SLIGHT
RISK FOR SEVERE STORMS TUESDAY NIGHT...GENERALLY ALONG AND WEST OF
A LINE FROM WAYNESBORO TO SPRINGFIELD. APPEARS BEST CHANCE FOR ANY
SEVERE WEATHER IN OUR CWA WILL BE IN THE 03Z-12Z TIMEFRAME AS
SHORTWAVE TROUGH AXIS MOVES ACROSS...BUT NOCTURNAL TIMING MAY
REDUCE THE SEVERE POTENTIAL. FORECAST SOUNDINGS DO SHOW
SUBSTANTIAL MLCAPE AND MODERATE DEEP LAYER SHEAR TUESDAY
NIGHT...WHICH SUGGESTS POTENTIAL FOR A LOWER END THREAT OF SOME
DAMAGING WINDS OR LARGE HAIL. HOWEVER...ANY TORNADO THREAT
APPEARS VERY LOW IN OUR FORECAST AREA. MUCH BETTER CHANCES FOR
SEVERE STORMS WILL EXIST TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON/EVENING. NOTE THAT MUCH OF THE CWA EAST OF I-65 WILL
REMAIN DRY DURING THIS TIME PERIOD.

AS SHORTWAVE EXITS THE REGION ON WEDNESDAY...A COLD FRONT WILL
PUSH EASTWARD ACROSS THE MID STATE WITH ADDITIONAL SHOWERS AND
STORMS ANTICIPATED THROUGH THE DAY. ACTIVITY WILL END FROM WEST TO
EAST WEDNESDAY NIGHT AS MUCH COOLER AND DRIER AIR FILTERS IN.
BELOW NORMAL TEMPERATURES ARE THEN ANTICIPATED OVER THE WEEKEND
AS NORTHWEST FLOW BUILDS IN ALOFT...WITH LOWS IN THE 40S/50S AND
HIGHS IN THE 70S. MID STATE LOOKS TO STAY IN A NORTHWEST FLOW
PATTERN THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH A
GRADUAL WARMING TREND...BUT MAJOR DIFFERENCES EXIST BETWEEN THE
GFS/ECMWF NEXT WEEK REGARDING PRECIP CHANCES WITH GFS COMPLETELY
DRY BUT ECMWF SHOWING DAILY POPS. HAVE TRENDED TOWARDS THE GFS
FOR NOW BUT NOTE THAT EXTENDED FORECAST IS LOW CONFIDENCE.

&&

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

$$

AL

000
FXUS64 KMEG 211235
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
735 AM CDT TUE MAY 21 2013

.UPDATE...

UPDATED FOR 12Z AVIATION DISCUSSION.

&&

.PREV DISCUSSION... /ISSUED 551 AM CDT TUE MAY 21 2013/

DISCUSSION...09Z SURFACE ANALYSIS PLACES A SURFACE LOW OVER
EASTERN SOUTH DAKOTA WITH A COLD FRONT EXTENDING SOUTH FROM THE
LOW ACROSS WESTERN MISSOURI...THEN BACK INTO CENTRAL OKLAHOMA AND
BACK INTO TEXAS. MEANWHILE...SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH LAST NIGHT/S CONVECTIVE ACTIVITY OVER THE PLAINS AND WESTERN
SECTIONS OF THE LOWER MISSISSIPPI VALLEY PRODUCED DAMAGING WINDS
ACROSS PORTIONS OF EAST AND NORTHEAST ARKANSAS AND WEAKENED AS IT
MOVED EAST OF THE MISSISSIPPI RIVER. TEMPERATURES AS OF 4 AM CDT
ARE PREDOMINANTLY IN THE 60S AT MOST LOCATIONS. SEVERE
THUNDERSTORM POTENTIAL MAINLY LATER THIS AFTERNOON INTO TONIGHT
REMAINS THE MAIN FORECAST CONCERN IN THIS MORNING/S FORECAST
ISSUANCE.

SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH LAST NIGHTS CONVECTION HAS MOVED TO
PORTIONS OF WEST TENNESSEE NEAR THE MISSISSIPPI RIVER. REGIONAL
WSR-88D RADAR TRENDS SHOW A COUPLE OF ADDITIONAL LINES ACROSS
ARKANSAS...THE FIRST LINE ACROSS EAST AND NORTHEAST ARKANSAS...AND
A SECOND LINE BEGINNING TO APPROACH CENTRAL ARKANSAS. LATEST RADAR
TRENDS INDICATE LESS SURFACE BASED INSTABILITY ACROSS THE AREA AND
THESE TWO ADDITIONAL LINES ARE EXPECTED TO BE REMAIN ELEVATED AT
THIS TIME.

A SURFACE LOW NEAR MIDLAND TEXAS EARLY THIS MORNING WILL MOVE
INTO EASTERN OKLAHOMA BY LATE AFTERNOON...INTO NORTHWEST ARKANSAS
TONIGHT AND UP INTO THE OHIO RIVER VALLEY BY WEDNESDAY.
MEANWHILE...AN UPPER LEVEL TROUGH WILL BECOME NEGATIVELY TILTED
AS IT MOVES INTO THE MIDDLE AND LOWER MISSISSIPPI VALLEYS TONIGHT.
THE ATMOSPHERE IS EXPECTED TO RECOVER AND DESTABILIZE ONCE AGAIN
BY THIS AFTERNOON INTO TONIGHT. MODERATELY STEEP TO STEEP 700-500
MB LAYER MID LEVEL LAPSE RATES...0-6 KM BULK SHEAR VALUES BETWEEN
40 TO 50 KTS...SURFACE BASED CAPE VALUES BETWEEN 1500-2500 J/KG
ESPECIALLY DURING THE LATE AFTERNOON INTO THE EARLY
EVENING...NEARLY UNIDIRECTIONAL WINDS ALOFT...AND FAVORABLE UPPER
LEVEL DIVERGENCE PRODUCED BY THE LEFT EXIT REGION OF AN UPPER
LEVEL JET STREAK SUGGEST THE CONVECTIVE ACTIVITY WILL BE MOSTLY IN
THE FORM OF A LINE AS IT MOVES ACROSS THE MID SOUTH TONIGHT. THE
PRIMARY SEVERE WEATHER THREATS WILL BE LARGE HAIL AND DAMAGING
WINDS WITH ANY THUNDERSTORMS THAT REACH SEVERE LIMITS. A POTENTIAL
WILL ALSO EXIST FOR PERHAPS A TORNADO OR TWO EMBEDDED WITHIN THE
LINE AS IT MOVES ACROSS THE AREA. LOCALIZED FLASH FLOODING FROM
HEAVY RAINFALL WILL BE POSSIBLE AS PRECIPITABLE WATER VALUES WILL
RANGE FROM 1.5 TO 2 INCHES. WILL CONTINUE TO MONITOR TRENDS AND
CONSIDER THE POTENTIAL FOR A FLASH FLOOD WATCH MAINLY WEST OF THE
MISSISSIPPI RIVER TODAY AND TONIGHT IF SHORT TERM TRENDS SHOW AN
INCREASING POTENTIAL. WILL HIGHLIGHT SEVERE WEATHER THREATS IN THE
HAZARDOUS WEATHER OUTLOOK.

CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO WEDNESDAY
AS THE COLD FRONT MOVES THROUGH THE MID SOUTH AND GRADUALLY TAPER
OFF INTO WEDNESDAY NIGHT.

LONG TERM...(THURSDAY THROUGH MEMORIAL DAY)...LATEST LONG TERM
MODEL TRENDS INDICATE ANOTHER FRONT WILL MOVE THROUGH THE LOWER
MISSISSIPPI VALLEY THURSDAY. A POTENTIAL WILL EXIST FOR ADDITIONAL
SHOWERS AND THUNDERSTORMS TO DEVELOP BUT OVERALL CONFIDENCE IN
COVERAGE REMAINS LOW. HIGH PRESSURE IS EXPECTED TO BUILD INTO THE
MID SOUTH FOR THURSDAY NIGHT INTO FRIDAY WITH SLIGHTLY COOLER AIR
TEMPORARILY RETURNING BACK TO THE FORECAST AREA. LONG TERM MODELS
REMAIN IN DISAGREEMENT WITH THE OVERALL SYNOPTIC PATTERN AS THE
COLD FRONT RETURNS NORTH AS A WARM FRONT THIS WEEKEND INTO EARLY
NEXT WEEK. THE GFS REMAINS THE DRIER OF THE SOLUTIONS WITH THE
ECMWF SUGGESTING SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS
ESPECIALLY ALONG AND NORTH OF I-40 FOR THIS WEEKEND INTO MEMORIAL
DAY. HAVE OPTED TO LEAVE POPS OUT OF THE FORECAST UNTIL MODELS
COME INTO BETTER CONSENSUS.

CJC

&&

.AVIATION...
12Z TAF CYCLE

A COUPLE LINES OF THUNDERSTORMS WILL MOVE THROUGH THE REGION THIS
MORNING. ALL TAF SITES WILL REMAIN VFR THROUGHOUT MOST OF THE DAY
WITH THE EXCEPTION OF SOME TEMPO MVFR CIGS AT SITES MEM AND MKL.
MORE STORMS WILL DEVELOP LATER THIS AFTERNOON...SOME OF WHICH MAY
BECOME SEVERE AND WILL MOST LIKELY BE IN THE FORM OF A LINE...WITH
HEAVY RAIN TEMPORARILY AFFECTING VISBYS. SOME LLWS COULD ALSO BE
POSSIBLE THIS EVENING AS THE LLJ INCREASES.

VARIABLE WINDS THIS MORNING...DUE TO TEMPORARY WINDSHIFTS
ASSOICATED WITH THESE LINES OF STORMS MOVING THROUGH. WINDS WILL
INCREASE AND BECOME MORE SOUTHERLY AROUND 12-14 KTS WITH HIGHER GUSTS
16-24 KTS BY MID AFTN.

AC3

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  86  70  84  65 /  60  80  50  10
MKL  85  68  82  63 /  60  70  50  10
JBR  83  66  82  62 /  70  90  30  10
TUP  88  68  83  65 /  30  60  60  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMEG 211229
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
729 AM CDT TUE MAY 21 2013

.UPDATE...

&&

.PREV DISCUSSION... /ISSUED 551 AM CDT TUE MAY 21 2013/

DISCUSSION...09Z SURFACE ANALYSIS PLACES A SURFACE LOW OVER
EASTERN SOUTH DAKOTA WITH A COLD FRONT EXTENDING SOUTH FROM THE
LOW ACROSS WESTERN MISSOURI...THEN BACK INTO CENTRAL OKLAHOMA AND
BACK INTO TEXAS. MEANWHILE...SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH LAST NIGHT/S CONVECTIVE ACTIVITY OVER THE PLAINS AND WESTERN
SECTIONS OF THE LOWER MISSISSIPPI VALLEY PRODUCED DAMAGING WINDS
ACROSS PORTIONS OF EAST AND NORTHEAST ARKANSAS AND WEAKENED AS IT
MOVED EAST OF THE MISSISSIPPI RIVER. TEMPERATURES AS OF 4 AM CDT
ARE PREDOMINANTLY IN THE 60S AT MOST LOCATIONS. SEVERE
THUNDERSTORM POTENTIAL MAINLY LATER THIS AFTERNOON INTO TONIGHT
REMAINS THE MAIN FORECAST CONCERN IN THIS MORNING/S FORECAST
ISSUANCE.

SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH LAST NIGHTS CONVECTION HAS MOVED TO
PORTIONS OF WEST TENNESSEE NEAR THE MISSISSIPPI RIVER. REGIONAL
WSR-88D RADAR TRENDS SHOW A COUPLE OF ADDITIONAL LINES ACROSS
ARKANSAS...THE FIRST LINE ACROSS EAST AND NORTHEAST ARKANSAS...AND
A SECOND LINE BEGINNING TO APPROACH CENTRAL ARKANSAS. LATEST RADAR
TRENDS INDICATE LESS SURFACE BASED INSTABILITY ACROSS THE AREA AND
THESE TWO ADDITIONAL LINES ARE EXPECTED TO BE REMAIN ELEVATED AT
THIS TIME.

A SURFACE LOW NEAR MIDLAND TEXAS EARLY THIS MORNING WILL MOVE
INTO EASTERN OKLAHOMA BY LATE AFTERNOON...INTO NORTHWEST ARKANSAS
TONIGHT AND UP INTO THE OHIO RIVER VALLEY BY WEDNESDAY.
MEANWHILE...AN UPPER LEVEL TROUGH WILL BECOME NEGATIVELY TILTED
AS IT MOVES INTO THE MIDDLE AND LOWER MISSISSIPPI VALLEYS TONIGHT.
THE ATMOSPHERE IS EXPECTED TO RECOVER AND DESTABILIZE ONCE AGAIN
BY THIS AFTERNOON INTO TONIGHT. MODERATELY STEEP TO STEEP 700-500
MB LAYER MID LEVEL LAPSE RATES...0-6 KM BULK SHEAR VALUES BETWEEN
40 TO 50 KTS...SURFACE BASED CAPE VALUES BETWEEN 1500-2500 J/KG
ESPECIALLY DURING THE LATE AFTERNOON INTO THE EARLY
EVENING...NEARLY UNIDIRECTIONAL WINDS ALOFT...AND FAVORABLE UPPER
LEVEL DIVERGENCE PRODUCED BY THE LEFT EXIT REGION OF AN UPPER
LEVEL JET STREAK SUGGEST THE CONVECTIVE ACTIVITY WILL BE MOSTLY IN
THE FORM OF A LINE AS IT MOVES ACROSS THE MID SOUTH TONIGHT. THE
PRIMARY SEVERE WEATHER THREATS WILL BE LARGE HAIL AND DAMAGING
WINDS WITH ANY THUNDERSTORMS THAT REACH SEVERE LIMITS. A POTENTIAL
WILL ALSO EXIST FOR PERHAPS A TORNADO OR TWO EMBEDDED WITHIN THE
LINE AS IT MOVES ACROSS THE AREA. LOCALIZED FLASH FLOODING FROM
HEAVY RAINFALL WILL BE POSSIBLE AS PRECIPITABLE WATER VALUES WILL
RANGE FROM 1.5 TO 2 INCHES. WILL CONTINUE TO MONITOR TRENDS AND
CONSIDER THE POTENTIAL FOR A FLASH FLOOD WATCH MAINLY WEST OF THE
MISSISSIPPI RIVER TODAY AND TONIGHT IF SHORT TERM TRENDS SHOW AN
INCREASING POTENTIAL. WILL HIGHLIGHT SEVERE WEATHER THREATS IN THE
HAZARDOUS WEATHER OUTLOOK.

CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO WEDNESDAY
AS THE COLD FRONT MOVES THROUGH THE MID SOUTH AND GRADUALLY TAPER
OFF INTO WEDNESDAY NIGHT.

LONG TERM...(THURSDAY THROUGH MEMORIAL DAY)...LATEST LONG TERM
MODEL TRENDS INDICATE ANOTHER FRONT WILL MOVE THROUGH THE LOWER
MISSISSIPPI VALLEY THURSDAY. A POTENTIAL WILL EXIST FOR ADDITIONAL
SHOWERS AND THUNDERSTORMS TO DEVELOP BUT OVERALL CONFIDENCE IN
COVERAGE REMAINS LOW. HIGH PRESSURE IS EXPECTED TO BUILD INTO THE
MID SOUTH FOR THURSDAY NIGHT INTO FRIDAY WITH SLIGHTLY COOLER AIR
TEMPORARILY RETURNING BACK TO THE FORECAST AREA. LONG TERM MODELS
REMAIN IN DISAGREEMENT WITH THE OVERALL SYNOPTIC PATTERN AS THE
COLD FRONT RETURNS NORTH AS A WARM FRONT THIS WEEKEND INTO EARLY
NEXT WEEK. THE GFS REMAINS THE DRIER OF THE SOLUTIONS WITH THE
ECMWF SUGGESTING SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS
ESPECIALLY ALONG AND NORTH OF I-40 FOR THIS WEEKEND INTO MEMORIAL
DAY. HAVE OPTED TO LEAVE POPS OUT OF THE FORECAST UNTIL MODELS
COME INTO BETTER CONSENSUS.

CJC

&&

.AVIATION...
12Z TAF CYCLE

A COUPLE LINES OF THUNDERSTORMS WILL MOVE THROUGH THE REGION THIS
MORNING. ALL TAF SITES WILL REMAIN VFR THROUGHOUT MOST OF THE DAY
WITH THE EXCEPTION OF SOME TEMPO MVFR CIGS AT SITES MEM AND MKL.
MORE STORMS WILL DEVELOP LATER THIS AFTERNOON...SOME OF WHICH MAY
BECOME SEVERE AND WILL MOST LIKELY BE IN THE FORM OF A LINE...WITH
HEAVY RAIN TEMPORARILY AFFECTING VISBYS. SOME LLWS COULD ALSO BE
POSSIBLE THIS EVENING AS THE LLJ INCREASES.

VARIABLE WINDS THIS MORNING...DUE TO TEMPORARY WINDSHIFTS
ASSOICATED WITH THESE LINES OF STORMS MOVING THROUGH. WINDS WILL
INCREASE AND BECOME MORE SOUTHERLY AROUND 12-14 KTS WITH HIGHER GUSTS
16-24 KTS BY MID AFTN.

AC3

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  86  70  84  65 /  50  80  50  10
MKL  85  68  82  63 /  30  70  50  10
JBR  83  66  82  62 /  70  90  30  10
TUP  88  68  83  65 /  20  60  60  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KOHX 211215
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
715 AM CDT TUE MAY 21 2013

.MESOSCALE UPDATE...

CURRENT RADAR IMAGERY SHOWS THAT THE HRRR APPEARS TO BE WINNING
WITH ITS DEPICTION OF MULTIPLE ROUNDS OF STORMS MOVING ACROSS THE
MID STATE. INITIAL LINE OF STORMS CONTINUES TO COLLAPSE AS IT
MOVES EAST OF THE I-65 CORRIDOR...BUT A SECOND LINE IS APPROACHING
THE WESTERN CWA BORDER. A THIRD AND MUCH MORE INTENSE LINE OF
STORMS IS MOVING ACROSS EASTERN ARKANSAS TOWARDS THE MID STATE.
THUS APPEARS SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGHOUT
THE DAY AND EVENTUALLY SPREAD ACROSS THE ENTIRE CWA...AND HAVE
BUMPED UP POPS AND LOWERED HIGH TEMPS ACCORDINGLY. 12Z OHX
SOUNDING PRIOR TO THE INITIAL LINE OF STORMS HAD CONSIDERABLE
POTENTIAL INSTABILITY WITH AN LI OF -10 AND VERY STEEP LAPSE
RATES. THUS CANNOT RULE OUT SOME STRONG TO SEVERE STORMS WITH
THESE NEXT TWO LINES OF STORMS LATER THIS MORNING AND
AFTERNOON...WITH THE MAIN THREAT BEING DAMAGING WINDS.

SHAMBURGER

&&

.PREV DISCUSSION... /ISSUED 601 AM CDT TUE MAY 21 2013/

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

AVIATION...LINE OF OVERNIGHT CONVECTION HAS STAYED TOGETHER AND
MOVED INTO MIDDLE TENNESSEE EARLY THIS MORNING, SO RAIN IS PART OF
THE INITIAL PERIOD OF THE TAF`S, ALONG WITH SOME FOG AT CSV. LOOK
FOR A REPRIEVE FROM THE WEATHER LATER THIS MORNING AND LASTING
THROUGH THE AFTERNOON, WITH A LONG STRETCH OF VFR WX. A COLD FRONT
APPROACHING FROM THE WEST WILL THEN BEGIN SPREADING ANOTHER ROUND
OF ACTIVE WEATHER ACROSS MIDDLE TENNESSEE THIS EVENING AND
OVERNIGHT, WITH THUNDERSTORMS POSSIBLE.

PREV DISCUSSION... /ISSUED 321 AM CDT TUE MAY 21 2013/

SHORT TERM...

RADAR IMAGERY THIS MORNING SHOWS AN EXTENSIVE LINE OF SHOWERS AND
THUNDERSTORMS FROM THE GREAT LAKES SOUTHWARD INTO WESTERN
TENNESSEE...WITH ACTIVITY NOW APPROACHING OUR WESTERN CWA BORDER.
ALTHOUGH MCS HAS SHOWN AN OVERALL WEAKENING TREND...SATELLITE
IMAGERY SHOWS NEW UPDRAFTS DEVELOPING ALONG LEADING EDGE OF COLD
POOL WITH CLOUD TOPS COOLING. LATEST SHORT TERM MODEL GUIDANCE
SUCH AS THE 4 KM WRF...HRRR...AND NSSL WRF ALL BRING ACTIVITY INTO
OUR WESTERN ZONES IN A FEW HOURS BEFORE DIMINISHING LATER THIS
MORNING...AND THUS WILL RAISE POPS SUBSTANTIALLY OVER GUIDANCE FOR
THE PRE-FIRST AND FIRST PERIOD OF THE FORECAST. ALSO BUMPED UP
CLOUD COVER AND WENT SIGNIFICANTLY BELOW MOS GUIDANCE HIGHS FOR
TODAY DUE TO ANTICIPATED CLOUDS/PRECIP. NO SEVERE WEATHER IS
EXPECTED WITH THESE STORMS THIS MORNING ALTHOUGH SOME GUSTY WINDS
MAY OCCUR. CHANGES TO THE FORECAST ARE LIKELY DEPENDING ON HOW
CURRENT ACTIVITY EVOLVES.

MODELS INDICATE A SHARP SHORTWAVE TROUGH CURRENTLY SEEN ON WATER
VAPOR IMAGERY OVER NEW MEXICO WILL SWING THROUGH THE SOUTHERN
PLAINS TODAY...THEN ACROSS THE OHIO VALLEY AND NORTHWEST PART OF
OUR FORECAST AREA TUESDAY NIGHT. EXPECTING NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON...THEN SPREAD INTO WESTERN TENNESSEE AND THE NORTHWEST
MID STATE TUESDAY EVENING AND ESPECIALLY AFTER MIDNIGHT TUESDAY
NIGHT. SPC HAS THE NORTHWEST PART OF THE FORECAST AREA IN A SLIGHT
RISK FOR SEVERE STORMS TUESDAY NIGHT...GENERALLY ALONG AND WEST OF
A LINE FROM WAYNESBORO TO SPRINGFIELD. APPEARS BEST CHANCE FOR ANY
SEVERE WEATHER IN OUR CWA WILL BE IN THE 03Z-12Z TIMEFRAME AS
SHORTWAVE TROUGH AXIS MOVES ACROSS...BUT NOCTURNAL TIMING MAY
REDUCE THE SEVERE POTENTIAL. FORECAST SOUNDINGS DO SHOW
SUBSTANTIAL MLCAPE AND MODERATE DEEP LAYER SHEAR TUESDAY
NIGHT...WHICH SUGGESTS POTENTIAL FOR A LOWER END THREAT OF SOME
DAMAGING WINDS OR LARGE HAIL. HOWEVER...ANY TORNADO THREAT
APPEARS VERY LOW IN OUR FORECAST AREA. MUCH BETTER CHANCES FOR
SEVERE STORMS WILL EXIST TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON/EVENING. NOTE THAT MUCH OF THE CWA EAST OF I-65 WILL
REMAIN DRY DURING THIS TIME PERIOD.

AS SHORTWAVE EXITS THE REGION ON WEDNESDAY...A COLD FRONT WILL
PUSH EASTWARD ACROSS THE MID STATE WITH ADDITIONAL SHOWERS AND
STORMS ANTICIPATED THROUGH THE DAY. ACTIVITY WILL END FROM WEST TO
EAST WEDNESDAY NIGHT AS MUCH COOLER AND DRIER AIR FILTERS IN.
BELOW NORMAL TEMPERATURES ARE THEN ANTICIPATED OVER THE WEEKEND
AS NORTHWEST FLOW BUILDS IN ALOFT...WITH LOWS IN THE 40S/50S AND
HIGHS IN THE 70S. MID STATE LOOKS TO STAY IN A NORTHWEST FLOW
PATTERN THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH A
GRADUAL WARMING TREND...BUT MAJOR DIFFERENCES EXIST BETWEEN THE
GFS/ECMWF NEXT WEEK REGARDING PRECIP CHANCES WITH GFS COMPLETELY
DRY BUT ECMWF SHOWING DAILY POPS. HAVE TRENDED TOWARDS THE GFS
FOR NOW BUT NOTE THAT EXTENDED FORECAST IS LOW CONFIDENCE.

&&

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

$$

000
FXUS64 KMRX 211125
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
725 AM EDT TUE MAY 21 2013

.AVIATION...
MAIN CONCERN WILL BE FOG..ESPECIALLY AT TRI..WHERE VLIFR/LIFR
CONDITIONS DUE TO VISIBILITY RESTRICTIONS. FOG WILL
DISSIPATE BY 14Z..THEN NEXT CONCERN WILL BE THE POTENTIAL OF
AFTERNOON/EARLY EVENING THUNDERSTORMS AT ALL TAF SITES. EVEN THOUGH
UPPER RIDGE WILL REMAIN...CONVECTION ACROSS MIDDLE TENNESSEE WILL
LIKELY RE-DEVELOP OVER THE PLATEAU..THEN MOVE INTO EAST TENNESSEE
DURING THE AFTERNOON. SOME STRONG-SEVERE THUNDERSTORMS ARE POSSIBLE
WITH THE MAIN CONCERN BEING DAMAGING DOWNBURST WINDS AND HAIL.

FOR TONIGHT...FOG RE-DEVELOPMENT IS EXPECTED..ESPECIALLY AT TRI..
WHERE FLIGHT CONDITIONS WILL DROP TO MVFR AND POSSIBLY IFR AT TRI.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

000
FXUS64 KOHX 211101
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
601 AM CDT TUE MAY 21 2013

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

&&

.AVIATION...LINE OF OVERNIGHT CONVECTION HAS STAYED TOGETHER AND
MOVED INTO MIDDLE TENNESSEE EARLY THIS MORNING, SO RAIN IS PART OF
THE INITIAL PERIOD OF THE TAF`S, ALONG WITH SOME FOG AT CSV. LOOK
FOR A REPRIEVE FROM THE WEATHER LATER THIS MORNING AND LASTING
THROUGH THE AFTERNOON, WITH A LONG STRETCH OF VFR WX. A COLD FRONT
APPROACHING FROM THE WEST WILL THEN BEGIN SPREADING ANOTHER ROUND
OF ACTIVE WEATHER ACROSS MIDDLE TENNESSEE THIS EVENING AND
OVERNIGHT, WITH THUNDERSTORMS POSSIBLE.

&&

.PREV DISCUSSION... /ISSUED 321 AM CDT TUE MAY 21 2013/

SHORT TERM...

RADAR IMAGERY THIS MORNING SHOWS AN EXTENSIVE LINE OF SHOWERS AND
THUNDERSTORMS FROM THE GREAT LAKES SOUTHWARD INTO WESTERN
TENNESSEE...WITH ACTIVITY NOW APPROACHING OUR WESTERN CWA BORDER.
ALTHOUGH MCS HAS SHOWN AN OVERALL WEAKENING TREND...SATELLITE
IMAGERY SHOWS NEW UPDRAFTS DEVELOPING ALONG LEADING EDGE OF COLD
POOL WITH CLOUD TOPS COOLING. LATEST SHORT TERM MODEL GUIDANCE
SUCH AS THE 4 KM WRF...HRRR...AND NSSL WRF ALL BRING ACTIVITY INTO
OUR WESTERN ZONES IN A FEW HOURS BEFORE DIMINISHING LATER THIS
MORNING...AND THUS WILL RAISE POPS SUBSTANTIALLY OVER GUIDANCE FOR
THE PRE-FIRST AND FIRST PERIOD OF THE FORECAST. ALSO BUMPED UP
CLOUD COVER AND WENT SIGNIFICANTLY BELOW MOS GUIDANCE HIGHS FOR
TODAY DUE TO ANTICIPATED CLOUDS/PRECIP. NO SEVERE WEATHER IS
EXPECTED WITH THESE STORMS THIS MORNING ALTHOUGH SOME GUSTY WINDS
MAY OCCUR. CHANGES TO THE FORECAST ARE LIKELY DEPENDING ON HOW
CURRENT ACTIVITY EVOLVES.

MODELS INDICATE A SHARP SHORTWAVE TROUGH CURRENTLY SEEN ON WATER
VAPOR IMAGERY OVER NEW MEXICO WILL SWING THROUGH THE SOUTHERN
PLAINS TODAY...THEN ACROSS THE OHIO VALLEY AND NORTHWEST PART OF
OUR FORECAST AREA TUESDAY NIGHT. EXPECTING NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON...THEN SPREAD INTO WESTERN TENNESSEE AND THE NORTHWEST
MID STATE TUESDAY EVENING AND ESPECIALLY AFTER MIDNIGHT TUESDAY
NIGHT. SPC HAS THE NORTHWEST PART OF THE FORECAST AREA IN A SLIGHT
RISK FOR SEVERE STORMS TUESDAY NIGHT...GENERALLY ALONG AND WEST OF
A LINE FROM WAYNESBORO TO SPRINGFIELD. APPEARS BEST CHANCE FOR ANY
SEVERE WEATHER IN OUR CWA WILL BE IN THE 03Z-12Z TIMEFRAME AS
SHORTWAVE TROUGH AXIS MOVES ACROSS...BUT NOCTURNAL TIMING MAY
REDUCE THE SEVERE POTENTIAL. FORECAST SOUNDINGS DO SHOW
SUBSTANTIAL MLCAPE AND MODERATE DEEP LAYER SHEAR TUESDAY
NIGHT...WHICH SUGGESTS POTENTIAL FOR A LOWER END THREAT OF SOME
DAMAGING WINDS OR LARGE HAIL. HOWEVER...ANY TORNADO THREAT
APPEARS VERY LOW IN OUR FORECAST AREA. MUCH BETTER CHANCES FOR
SEVERE STORMS WILL EXIST TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON/EVENING. NOTE THAT MUCH OF THE CWA EAST OF I-65 WILL
REMAIN DRY DURING THIS TIME PERIOD.

AS SHORTWAVE EXITS THE REGION ON WEDNESDAY...A COLD FRONT WILL
PUSH EASTWARD ACROSS THE MID STATE WITH ADDITIONAL SHOWERS AND
STORMS ANTICIPATED THROUGH THE DAY. ACTIVITY WILL END FROM WEST TO
EAST WEDNESDAY NIGHT AS MUCH COOLER AND DRIER AIR FILTERS IN.
BELOW NORMAL TEMPERATURES ARE THEN ANTICIPATED OVER THE WEEKEND
AS NORTHWEST FLOW BUILDS IN ALOFT...WITH LOWS IN THE 40S/50S AND
HIGHS IN THE 70S. MID STATE LOOKS TO STAY IN A NORTHWEST FLOW
PATTERN THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH A
GRADUAL WARMING TREND...BUT MAJOR DIFFERENCES EXIST BETWEEN THE
GFS/ECMWF NEXT WEEK REGARDING PRECIP CHANCES WITH GFS COMPLETELY
DRY BUT ECMWF SHOWING DAILY POPS. HAVE TRENDED TOWARDS THE GFS
FOR NOW BUT NOTE THAT EXTENDED FORECAST IS LOW CONFIDENCE.

&&

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

$$

ROSE

000
FXUS64 KMEG 211051
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
551 AM CDT TUE MAY 21 2013

.DISCUSSION...09Z SURFACE ANALYSIS PLACES A SURFACE LOW OVER
EASTERN SOUTH DAKOTA WITH A COLD FRONT EXTENDING SOUTH FROM THE
LOW ACROSS WESTERN MISSOURI...THEN BACK INTO CENTRAL OKLAHOMA AND
BACK INTO TEXAS. MEANWHILE...SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH LAST NIGHT/S CONVECTIVE ACTIVITY OVER THE PLAINS AND WESTERN
SECTIONS OF THE LOWER MISSISSIPPI VALLEY PRODUCED DAMAGING WINDS
ACROSS PORTIONS OF EAST AND NORTHEAST ARKANSAS AND WEAKENED AS IT
MOVED EAST OF THE MISSISSIPPI RIVER. TEMPERATURES AS OF 4 AM CDT
ARE PREDOMINANTLY IN THE 60S AT MOST LOCATIONS. SEVERE
THUNDERSTORM POTENTIAL MAINLY LATER THIS AFTERNOON INTO TONIGHT
REMAINS THE MAIN FORECAST CONCERN IN THIS MORNING/S FORECAST
ISSUANCE.

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH LAST NIGHTS CONVECTION HAS MOVED TO
PORTIONS OF WEST TENNESSEE NEAR THE MISSISSIPPI RIVER. REGIONAL
WSR-88D RADAR TRENDS SHOW A COUPLE OF ADDITIONAL LINES ACROSS
ARKANSAS...THE FIRST LINE ACROSS EAST AND NORTHEAST ARKANSAS...AND
A SECOND LINE BEGINNING TO APPROACH CENTRAL ARKANSAS. LATEST RADAR
TRENDS INDICATE LESS SURFACE BASED INSTABILITY ACROSS THE AREA AND
THESE TWO ADDITIONAL LINES ARE EXPECTED TO BE REMAIN ELEVATED AT
THIS TIME.

A SURFACE LOW NEAR MIDLAND TEXAS EARLY THIS MORNING WILL MOVE
INTO EASTERN OKLAHOMA BY LATE AFTERNOON...INTO NORTHWEST ARKANSAS
TONIGHT AND UP INTO THE OHIO RIVER VALLEY BY WEDNESDAY.
MEANWHILE...AN UPPER LEVEL TROUGH WILL BECOME NEGATIVELY TILTED
AS IT MOVES INTO THE MIDDLE AND LOWER MISSISSIPPI VALLEYS TONIGHT.
THE ATMOSPHERE IS EXPECTED TO RECOVER AND DESTABILIZE ONCE AGAIN
BY THIS AFTERNOON INTO TONIGHT. MODERATELY STEEP TO STEEP 700-500
MB LAYER MID LEVEL LAPSE RATES...0-6 KM BULK SHEAR VALUES BETWEEN
40 TO 50 KTS...SURFACE BASED CAPE VALUES BETWEEN 1500-2500 J/KG
ESPECIALLY DURING THE LATE AFTERNOON INTO THE EARLY
EVENING...NEARLY UNIDIRECTIONAL WINDS ALOFT...AND FAVORABLE UPPER
LEVEL DIVERGENCE PRODUCED BY THE LEFT EXIT REGION OF AN UPPER
LEVEL JET STREAK SUGGEST THE CONVECTIVE ACTIVITY WILL BE MOSTLY IN
THE FORM OF A LINE AS IT MOVES ACROSS THE MID SOUTH TONIGHT. THE
PRIMARY SEVERE WEATHER THREATS WILL BE LARGE HAIL AND DAMAGING
WINDS WITH ANY THUNDERSTORMS THAT REACH SEVERE LIMITS. A POTENTIAL
WILL ALSO EXIST FOR PERHAPS A TORNADO OR TWO EMBEDDED WITHIN THE
LINE AS IT MOVES ACROSS THE AREA. LOCALIZED FLASH FLOODING FROM
HEAVY RAINFALL WILL BE POSSIBLE AS PRECIPITABLE WATER VALUES WILL
RANGE FROM 1.5 TO 2 INCHES. WILL CONTINUE TO MONITOR TRENDS AND
CONSIDER THE POTENTIAL FOR A FLASH FLOOD WATCH MAINLY WEST OF THE
MISSISSIPPI RIVER TODAY AND TONIGHT IF SHORT TERM TRENDS SHOW AN
INCREASING POTENTIAL. WILL HIGHLIGHT SEVERE WEATHER THREATS IN THE
HAZARDOUS WEATHER OUTLOOK.

CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO WEDNESDAY
AS THE COLD FRONT MOVES THROUGH THE MID SOUTH AND GRADUALLY TAPER
OFF INTO WEDNESDAY NIGHT.

.LONG TERM...(THURSDAY THROUGH MEMORIAL DAY)...LATEST LONG TERM
MODEL TRENDS INDICATE ANOTHER FRONT WILL MOVE THROUGH THE LOWER
MISSISSIPPI VALLEY THURSDAY. A POTENTIAL WILL EXIST FOR ADDITIONAL
SHOWERS AND THUNDERSTORMS TO DEVELOP BUT OVERALL CONFIDENCE IN
COVERAGE REMAINS LOW. HIGH PRESSURE IS EXPECTED TO BUILD INTO THE
MID SOUTH FOR THURSDAY NIGHT INTO FRIDAY WITH SLIGHTLY COOLER AIR
TEMPORARILY RETURNING BACK TO THE FORECAST AREA. LONG TERM MODELS
REMAIN IN DISAGREEMENT WITH THE OVERALL SYNOPTIC PATTERN AS THE
COLD FRONT RETURNS NORTH AS A WARM FRONT THIS WEEKEND INTO EARLY
NEXT WEEK. THE GFS REMAINS THE DRIER OF THE SOLUTIONS WITH THE
ECMWF SUGGESTING SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS
ESPECIALLY ALONG AND NORTH OF I-40 FOR THIS WEEKEND INTO MEMORIAL
DAY. HAVE OPTED TO LEAVE POPS OUT OF THE FORECAST UNTIL MODELS
COME INTO BETTER CONSENSUS.

CJC

&&

.AVIATION...
06Z TAF CYCLE

A WEAKENING LINE OF SHRAS AND TSRAS WILL PUSH INTO WESTERN PARTS OF THE
MIDSOUTH OVERNIGHT. EXPECT THE LINE TO HOLD TOGETHER AND REACH
KJBR AFT 21/08Z AND GLANCE KMEM AFT 21/10Z. KMKL AND KTUP WILL
REMAIN VFR FOR THE REMAINDER OF THE NIGHT. EXPECT SOME LEFTOVER
SHRAS AND PATCHY MVFR CIGS TUESDAY MORNING. ANY LOWER CONDS WILL
IMPROVE TO VFR BY MIDDAY TUESDAY. EXPECT ANOTHER ROUND OF SHRAS AND
TSRA TO DEVELOP AND START TO IMPACT WESTERN AREAS OF THE MIDSOUTH
LATE TUESDAY AFTN INTO TUESDAY EVENING. ADDED TEMPOS FOR TSRAS AT
KJBR...KMEM AND KMKL FOR TUESDAY EVENING.

SOUTH WINDS AT 6-10 KTS TONIGHT...INCREASING TO 12-14 KTS WITH
HIGHER GUSTS BY TUESDAY AFTN.

SJM

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  86  70  84  65 /  50  80  50  10
MKL  85  68  82  63 /  30  70  50  10
JBR  83  66  82  62 /  70  90  30  10
TUP  88  68  83  65 /  20  60  60  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KOHX 211041
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
541 AM CDT TUE MAY 21 2013

.MESOSCALE UPDATE...

RADAR INDICATES LINE OF THUNDERSTORMS CURRENTLY STRETCHES FROM
SPRINGFIELD TO LINDEN AND CONTINUES TO WEAKEN AS IT OUTRUNS WHAT
LITTLE INSTABILITY REMAINS. HOWEVER...LINE SHOULD REACH THE I-65
CORRIDOR AND NASHVILLE METRO AREA SOON WITH LIGHT TO MODERATE RAIN
AND A FEW LIGHTNING STRIKES EXPECTED. THE LINE SHOULD COLLAPSE AS
IT CONTINUES FURTHER EAST AND RUNS INTO THE UPPER LEVEL RIDGE IN
PLACE. MEANWHILE...TWO ADDITIONAL LINES OF STORMS ARE CURRENTLY
ONGOING ACROSS ARKANSAS...AND LATEST HRRR RUNS INDICATE THESE
STORMS MAY ALSO REACH THE MID STATE LATER THIS MORNING. VERY
UNCERTAIN ON IF THIS WILL OCCUR...BUT IF IT DOES POPS WOULD NEED
TO BE RAISED AND HIGH TEMPS LOWERED SUBSTANTIALLY DUE TO THE
CLOUD COVER/PRECIP. FOR NOW HAVE BUMPED UP POPS FOR THE WESTERN
TWO- THIRDS OF THE CWA FOR THE MORNING PERIOD...AND WILL TAKE A
WAIT AND SEE APPROACH ON THE ACTIVITY TO OUR WEST BEFORE CHANGING
GRIDS/ZONES FURTHER. SHOULD CONVECTION CONTINUE TO AFFECT THE MID
STATE THROUGHOUT THE DAY AS THE HRRR SUGGESTS...THIS WOULD LIKELY
REDUCE THE SEVERE WEATHER THREAT TUESDAY NIGHT.

SHAMBURGER

&&

.PREV DISCUSSION... /ISSUED 425 AM CDT TUE MAY 21 2013/

MESOSCALE UPDATE...

LINE OF THUNDERSTORMS HAS ENTERED STEWART COUNTY WITH WIND GUSTS
ALONG LEADING EDGE UP TO 50 MPH POSSIBLE PER HPX BASE VELOCITY
RADAR DATA. ALSO CANNOT RULE OUT SOME SMALL HAIL AS UPDRAFTS
REGENERATE ALONG THE FRONT SIDE OF COLD POOL AS LINE RACES
EASTWARD AT UP TO 60 MPH. SPC MESOANALYSIS SHOWS INSTABILITY AXIS
OF UP TO 1000 J/KG ACROSS NORTHWEST ZONES...DECREASING TO 500 J/KG
NEAR I-65 AND TO NEAR ZERO ON THE PLATEAU. THUS EXPECT LINE OF
STORMS TO CONTINUE GRADUALLY WEAKENING AS IT MOVES FURTHER
EASTWARD...BUT WILL CONTINUE TO CLOSELY MONITOR.

SHAMBURGER

PREV DISCUSSION... /ISSUED 321 AM CDT TUE MAY 21 2013/

SHORT TERM...

RADAR IMAGERY THIS MORNING SHOWS AN EXTENSIVE LINE OF SHOWERS AND
THUNDERSTORMS FROM THE GREAT LAKES SOUTHWARD INTO WESTERN
TENNESSEE...WITH ACTIVITY NOW APPROACHING OUR WESTERN CWA BORDER.
ALTHOUGH MCS HAS SHOWN AN OVERALL WEAKENING TREND...SATELLITE
IMAGERY SHOWS NEW UPDRAFTS DEVELOPING ALONG LEADING EDGE OF COLD
POOL WITH CLOUD TOPS COOLING. LATEST SHORT TERM MODEL GUIDANCE
SUCH AS THE 4 KM WRF...HRRR...AND NSSL WRF ALL BRING ACTIVITY INTO
OUR WESTERN ZONES IN A FEW HOURS BEFORE DIMINISHING LATER THIS
MORNING...AND THUS WILL RAISE POPS SUBSTANTIALLY OVER GUIDANCE FOR
THE PRE-FIRST AND FIRST PERIOD OF THE FORECAST. ALSO BUMPED UP
CLOUD COVER AND WENT SIGNIFICANTLY BELOW MOS GUIDANCE HIGHS FOR
TODAY DUE TO ANTICIPATED CLOUDS/PRECIP. NO SEVERE WEATHER IS
EXPECTED WITH THESE STORMS THIS MORNING ALTHOUGH SOME GUSTY WINDS
MAY OCCUR. CHANGES TO THE FORECAST ARE LIKELY DEPENDING ON HOW
CURRENT ACTIVITY EVOLVES.

MODELS INDICATE A SHARP SHORTWAVE TROUGH CURRENTLY SEEN ON WATER
VAPOR IMAGERY OVER NEW MEXICO WILL SWING THROUGH THE SOUTHERN
PLAINS TODAY...THEN ACROSS THE OHIO VALLEY AND NORTHWEST PART OF
OUR FORECAST AREA TUESDAY NIGHT. EXPECTING NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON...THEN SPREAD INTO WESTERN TENNESSEE AND THE NORTHWEST
MID STATE TUESDAY EVENING AND ESPECIALLY AFTER MIDNIGHT TUESDAY
NIGHT. SPC HAS THE NORTHWEST PART OF THE FORECAST AREA IN A SLIGHT
RISK FOR SEVERE STORMS TUESDAY NIGHT...GENERALLY ALONG AND WEST OF
A LINE FROM WAYNESBORO TO SPRINGFIELD. APPEARS BEST CHANCE FOR ANY
SEVERE WEATHER IN OUR CWA WILL BE IN THE 03Z-12Z TIMEFRAME AS
SHORTWAVE TROUGH AXIS MOVES ACROSS...BUT NOCTURNAL TIMING MAY
REDUCE THE SEVERE POTENTIAL. FORECAST SOUNDINGS DO SHOW
SUBSTANTIAL MLCAPE AND MODERATE DEEP LAYER SHEAR TUESDAY
NIGHT...WHICH SUGGESTS POTENTIAL FOR A LOWER END THREAT OF SOME
DAMAGING WINDS OR LARGE HAIL. HOWEVER...ANY TORNADO THREAT
APPEARS VERY LOW IN OUR FORECAST AREA. MUCH BETTER CHANCES FOR
SEVERE STORMS WILL EXIST TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON/EVENING. NOTE THAT MUCH OF THE CWA EAST OF I-65 WILL
REMAIN DRY DURING THIS TIME PERIOD.

AS SHORTWAVE EXITS THE REGION ON WEDNESDAY...A COLD FRONT WILL
PUSH EASTWARD ACROSS THE MID STATE WITH ADDITIONAL SHOWERS AND
STORMS ANTICIPATED THROUGH THE DAY. ACTIVITY WILL END FROM WEST TO
EAST WEDNESDAY NIGHT AS MUCH COOLER AND DRIER AIR FILTERS IN.
BELOW NORMAL TEMPERATURES ARE THEN ANTICIPATED OVER THE WEEKEND
AS NORTHWEST FLOW BUILDS IN ALOFT...WITH LOWS IN THE 40S/50S AND
HIGHS IN THE 70S. MID STATE LOOKS TO STAY IN A NORTHWEST FLOW
PATTERN THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH A
GRADUAL WARMING TREND...BUT MAJOR DIFFERENCES EXIST BETWEEN THE
GFS/ECMWF NEXT WEEK REGARDING PRECIP CHANCES WITH GFS COMPLETELY
DRY BUT ECMWF SHOWING DAILY POPS. HAVE TRENDED TOWARDS THE GFS
FOR NOW BUT NOTE THAT EXTENDED FORECAST IS LOW CONFIDENCE.

&&

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

$$

000
FXUS64 KOHX 210925
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
425 AM CDT TUE MAY 21 2013

.MESOSCALE UPDATE...

LINE OF THUNDERSTORMS HAS ENTERED STEWART COUNTY WITH WIND GUSTS
ALONG LEADING EDGE UP TO 50 MPH POSSIBLE PER HPX BASE VELOCITY
RADAR DATA. ALSO CANNOT RULE OUT SOME SMALL HAIL AS UPDRAFTS
REGENERATE ALONG THE FRONT SIDE OF COLD POOL AS LINE RACES
EASTWARD AT UP TO 60 MPH. SPC MESOANALYSIS SHOWS INSTABILITY AXIS
OF UP TO 1000 J/KG ACROSS NORTHWEST ZONES...DECREASING TO 500 J/KG
NEAR I-65 AND TO NEAR ZERO ON THE PLATEAU. THUS EXPECT LINE OF
STORMS TO CONTINUE GRADUALLY WEAKENING AS IT MOVES FURTHER
EASTWARD...BUT WILL CONTINUE TO CLOSELY MONITOR.

SHAMBURGER

&&

.PREV DISCUSSION... /ISSUED 321 AM CDT TUE MAY 21 2013/

SHORT TERM...

RADAR IMAGERY THIS MORNING SHOWS AN EXTENSIVE LINE OF SHOWERS AND
THUNDERSTORMS FROM THE GREAT LAKES SOUTHWARD INTO WESTERN
TENNESSEE...WITH ACTIVITY NOW APPROACHING OUR WESTERN CWA BORDER.
ALTHOUGH MCS HAS SHOWN AN OVERALL WEAKENING TREND...SATELLITE
IMAGERY SHOWS NEW UPDRAFTS DEVELOPING ALONG LEADING EDGE OF COLD
POOL WITH CLOUD TOPS COOLING. LATEST SHORT TERM MODEL GUIDANCE
SUCH AS THE 4 KM WRF...HRRR...AND NSSL WRF ALL BRING ACTIVITY INTO
OUR WESTERN ZONES IN A FEW HOURS BEFORE DIMINISHING LATER THIS
MORNING...AND THUS WILL RAISE POPS SUBSTANTIALLY OVER GUIDANCE FOR
THE PRE-FIRST AND FIRST PERIOD OF THE FORECAST. ALSO BUMPED UP
CLOUD COVER AND WENT SIGNIFICANTLY BELOW MOS GUIDANCE HIGHS FOR
TODAY DUE TO ANTICIPATED CLOUDS/PRECIP. NO SEVERE WEATHER IS
EXPECTED WITH THESE STORMS THIS MORNING ALTHOUGH SOME GUSTY WINDS
MAY OCCUR. CHANGES TO THE FORECAST ARE LIKELY DEPENDING ON HOW
CURRENT ACTIVITY EVOLVES.

MODELS INDICATE A SHARP SHORTWAVE TROUGH CURRENTLY SEEN ON WATER
VAPOR IMAGERY OVER NEW MEXICO WILL SWING THROUGH THE SOUTHERN
PLAINS TODAY...THEN ACROSS THE OHIO VALLEY AND NORTHWEST PART OF
OUR FORECAST AREA TUESDAY NIGHT. EXPECTING NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON...THEN SPREAD INTO WESTERN TENNESSEE AND THE NORTHWEST
MID STATE TUESDAY EVENING AND ESPECIALLY AFTER MIDNIGHT TUESDAY
NIGHT. SPC HAS THE NORTHWEST PART OF THE FORECAST AREA IN A SLIGHT
RISK FOR SEVERE STORMS TUESDAY NIGHT...GENERALLY ALONG AND WEST OF
A LINE FROM WAYNESBORO TO SPRINGFIELD. APPEARS BEST CHANCE FOR ANY
SEVERE WEATHER IN OUR CWA WILL BE IN THE 03Z-12Z TIMEFRAME AS
SHORTWAVE TROUGH AXIS MOVES ACROSS...BUT NOCTURNAL TIMING MAY
REDUCE THE SEVERE POTENTIAL. FORECAST SOUNDINGS DO SHOW
SUBSTANTIAL MLCAPE AND MODERATE DEEP LAYER SHEAR TUESDAY
NIGHT...WHICH SUGGESTS POTENTIAL FOR A LOWER END THREAT OF SOME
DAMAGING WINDS OR LARGE HAIL. HOWEVER...ANY TORNADO THREAT
APPEARS VERY LOW IN OUR FORECAST AREA. MUCH BETTER CHANCES FOR
SEVERE STORMS WILL EXIST TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON/EVENING. NOTE THAT MUCH OF THE CWA EAST OF I-65 WILL
REMAIN DRY DURING THIS TIME PERIOD.

AS SHORTWAVE EXITS THE REGION ON WEDNESDAY...A COLD FRONT WILL
PUSH EASTWARD ACROSS THE MID STATE WITH ADDITIONAL SHOWERS AND
STORMS ANTICIPATED THROUGH THE DAY. ACTIVITY WILL END FROM WEST TO
EAST WEDNESDAY NIGHT AS MUCH COOLER AND DRIER AIR FILTERS IN.
BELOW NORMAL TEMPERATURES ARE THEN ANTICIPATED OVER THE WEEKEND
AS NORTHWEST FLOW BUILDS IN ALOFT...WITH LOWS IN THE 40S/50S AND
HIGHS IN THE 70S. MID STATE LOOKS TO STAY IN A NORTHWEST FLOW
PATTERN THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH A
GRADUAL WARMING TREND...BUT MAJOR DIFFERENCES EXIST BETWEEN THE
GFS/ECMWF NEXT WEEK REGARDING PRECIP CHANCES WITH GFS COMPLETELY
DRY BUT ECMWF SHOWING DAILY POPS. HAVE TRENDED TOWARDS THE GFS
FOR NOW BUT NOTE THAT EXTENDED FORECAST IS LOW CONFIDENCE.

&&

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

$$

000
FXUS64 KOHX 210821
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
321 AM CDT TUE MAY 21 2013

.SHORT TERM...

RADAR IMAGERY THIS MORNING SHOWS AN EXTENSIVE LINE OF SHOWERS AND
THUNDERSTORMS FROM THE GREAT LAKES SOUTHWARD INTO WESTERN
TENNESSEE...WITH ACTIVITY NOW APPROACHING OUR WESTERN CWA BORDER.
ALTHOUGH MCS HAS SHOWN AN OVERALL WEAKENING TREND...SATELLITE
IMAGERY SHOWS NEW UPDRAFTS DEVELOPING ALONG LEADING EDGE OF COLD
POOL WITH CLOUD TOPS COOLING. LATEST SHORT TERM MODEL GUIDANCE
SUCH AS THE 4 KM WRF...HRRR...AND NSSL WRF ALL BRING ACTIVITY INTO
OUR WESTERN ZONES IN A FEW HOURS BEFORE DIMINISHING LATER THIS
MORNING...AND THUS WILL RAISE POPS SUBSTANTIALLY OVER GUIDANCE FOR
THE PRE-FIRST AND FIRST PERIOD OF THE FORECAST. ALSO BUMPED UP
CLOUD COVER AND WENT SIGNIFICANTLY BELOW MOS GUIDANCE HIGHS FOR
TODAY DUE TO ANTICIPATED CLOUDS/PRECIP. NO SEVERE WEATHER IS
EXPECTED WITH THESE STORMS THIS MORNING ALTHOUGH SOME GUSTY WINDS
MAY OCCUR. CHANGES TO THE FORECAST ARE LIKELY DEPENDING ON HOW
CURRENT ACTIVITY EVOLVES.

MODELS INDICATE A SHARP SHORTWAVE TROUGH CURRENTLY SEEN ON WATER
VAPOR IMAGERY OVER NEW MEXICO WILL SWING THROUGH THE SOUTHERN
PLAINS TODAY...THEN ACROSS THE OHIO VALLEY AND NORTHWEST PART OF
OUR FORECAST AREA TUESDAY NIGHT. EXPECTING NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON...THEN SPREAD INTO WESTERN TENNESSEE AND THE NORTHWEST
MID STATE TUESDAY EVENING AND ESPECIALLY AFTER MIDNIGHT TUESDAY
NIGHT. SPC HAS THE NORTHWEST PART OF THE FORECAST AREA IN A SLIGHT
RISK FOR SEVERE STORMS TUESDAY NIGHT...GENERALLY ALONG AND WEST OF
A LINE FROM WAYNESBORO TO SPRINGFIELD. APPEARS BEST CHANCE FOR ANY
SEVERE WEATHER IN OUR CWA WILL BE IN THE 03Z-12Z TIMEFRAME AS
SHORTWAVE TROUGH AXIS MOVES ACROSS...BUT NOCTURNAL TIMING MAY
REDUCE THE SEVERE POTENTIAL. FORECAST SOUNDINGS DO SHOW
SUBSTANTIAL MLCAPE AND MODERATE DEEP LAYER SHEAR TUESDAY
NIGHT...WHICH SUGGESTS POTENTIAL FOR A LOWER END THREAT OF SOME
DAMAGING WINDS OR LARGE HAIL. HOWEVER...ANY TORNADO THREAT
APPEARS VERY LOW IN OUR FORECAST AREA. MUCH BETTER CHANCES FOR
SEVERE STORMS WILL EXIST TO OUR WEST ACROSS ARKANSAS TUESDAY
AFTERNOON/EVENING. NOTE THAT MUCH OF THE CWA EAST OF I-65 WILL
REMAIN DRY DURING THIS TIME PERIOD.

AS SHORTWAVE EXITS THE REGION ON WEDNESDAY...A COLD FRONT WILL
PUSH EASTWARD ACROSS THE MID STATE WITH ADDITIONAL SHOWERS AND
STORMS ANTICIPATED THROUGH THE DAY. ACTIVITY WILL END FROM WEST TO
EAST WEDNESDAY NIGHT AS MUCH COOLER AND DRIER AIR FILTERS IN.
BELOW NORMAL TEMPERATURES ARE THEN ANTICIPATED OVER THE WEEKEND
AS NORTHWEST FLOW BUILDS IN ALOFT...WITH LOWS IN THE 40S/50S AND
HIGHS IN THE 70S. MID STATE LOOKS TO STAY IN A NORTHWEST FLOW
PATTERN THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH A
GRADUAL WARMING TREND...BUT MAJOR DIFFERENCES EXIST BETWEEN THE
GFS/ECMWF NEXT WEEK REGARDING PRECIP CHANCES WITH GFS COMPLETELY
DRY BUT ECMWF SHOWING DAILY POPS. HAVE TRENDED TOWARDS THE GFS
FOR NOW BUT NOTE THAT EXTENDED FORECAST IS LOW CONFIDENCE.

&&

.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE      84  67  82  62 /  40  50  60  30
CLARKSVILLE    83  66  80  59 /  50  70  60  20
CROSSVILLE     80  63  80  61 /  30  40  60  50
COLUMBIA       84  67  82  62 /  40  50  60  30
LAWRENCEBURG   85  66  82  62 /  40  50  60  30
WAVERLY        84  67  80  60 /  50  70  60  20

&&

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

$$

SHAMBURGER

000
FXUS64 KMRX 210752
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
352 AM EDT TUE MAY 21 2013

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)...EARLY MORNING DENSE
FOG ACROSS MAINLY SOUTHWEST VIRGINIA AND NORTHEAST TENNESSEE.
CURRENTLY COVERAGE IS SCATTERED...PER SATELLITE/OBS...BUT WILL
MONITOR FOR POTENTIAL ADVISORY.

A LINE OF STORMS IS CURRENTLY ACROSS FAR WESTERN TENNESSEE. LATEST
NAM SUGGEST THE OUTFLOW BOUNDARY FROM THIS CONVECTION WILL MOVE
ACROSS TENNESSEE THIS MORNING/EARLY AFTERNOON AND BE LOCATED OVER
THE PLATEAU BY 16-18Z. AIRMASS WILL BE MODERATELY UNSTABLE WITH
CAPES OF 2000-2500 J/KG..SO SCATTERED TO BROKEN CONVECTION
ANTICIPATED ALONG THIS BOUNDARY AS WELL AS ALONG TERRAIN FEATURES.
A GOOD DEAL OF MID-LEVEL DRY AIR WILL PROMOTE DRY AIR ENTRAINMENT
INTO THE DOWNDRAFTS WITH DAMAGING WINDS A CONCERN. ALSO...WET BULB
ZERO HEIGHTS AND HAIL CAPE VALUES WILL BE FAVORABLE FOR MARGINAL
LARGE HAIL. HAVE INCLUDED WITHIN THE HWO.

CONVECTION WILL DIMINISH THIS EVENING DUE TO LOSS OF DAYTIME
HEATING.

FOR WEDNESDAY...AN APPROACHING FRONT AND LIKELY OUTFLOW BOUNDARIES
COMBINED WITH MARGINAL INSTABILITY WILL PRODUCE SCATTERED TO BROKEN
CONVECTION. MODELS CURRENTLY DO NOT FAVOR AN OUTBREAK OF SEVERE WEATHER..BUT
GIVEN THE INCREASING MID-LEVEL WINDS ASSOCIATED WITH UPPER TROUGH
OVER THE MID-WEST..WE WILL HAVE TO MONITOR FOR THE POSSIBILITY OF STRONG-
SEVERE STORMS.

.LONG TERM (THURSDAY THROUGH MONDAY)...UPPER TROUGH AMPLIFIES
THURSDAY INTO FRIDAY MAKING SLOW PROGRESS AS IT SHIFTS FROM THE
MISSISSIPPI VALLEY TO THE EASTERN SEABOARD BY 00Z SATURDAY. BUMPED
POPS UP SLIGHTLY ON THURSDAY WITH A COLD FRONT BUILDING THROUGH THE
SOUTHERN APPALACHIANS. MAINTAINED SOME CHANCE POPS THURSDAY NIGHT
TAPERING TO SLIGHT CHANCE ON FRIDAY AS MODELS INDICATE A FAIR AMOUNT
OF SHORT WAVE ENERGY AND DEEP MOISTURE ROTATING THROUGH THE EASTERN
U.S. LONG WAVE. STAYED WITH CONVECTION ON THURSDAY BUT WITH
INCREASING STABILITY THURSDAY NIGHT INTO FRIDAY USED SHOWER WORDING.
PREVAILING NORTHWEST FLOW WITH DRY ADVECTION AND A NICE EXPANSIVE
SURFACE RIDGE SHOULD ALLOW FOR A DRY PERIOD SATURDAY THROUGH SUNDAY.
GFS/CMC HINT AT THE PASSAGE OF A SHORT WAVE SUNDAY NIGHT INTO MONDAY
WITH LOW LEVEL WARM AND MOIST ADVECTION DEVELOPING ON THE BACK SIDE
OF THE DEPARTING RIDGE. THEREFORE KEPT A SLIGHT CHANCE FOR A SHOWER
SUNDAY NIGHT WITH THE POSSIBILITY OF A THUNDERSTORM ON
MONDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             88  65  85  63  84 /  30  30  60  50  30
KNOXVILLE MCGHEE TYSON AIRPORT, TN  87  65  84  63  81 /  30  30  50  50  40
OAK RIDGE, TN                       87  65  84  62  80 /  30  20  50  50  40
TRI CITIES AIRPORT, TN              85  59  84  59  77 /  20  20  60  50  50

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

000
FXUS64 KMRX 210521
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
121 AM EDT TUE MAY 21 2013

.AVIATION...
MAIN CONCERN WILL BE THE DEVELOPING FOG..ESPECIALLY AT TRI..WHERE
VLIFR/LIFR CONDITIONS DUE TO VISIBILITY RESTRICTIONS ARE ANTICIPATED.
FOG WILL DISSIPATE BY 14Z..THEN NEXT CONCERN WILL BE THE POTENTIAL OF
AFTERNOON/EARLY EVENING THUNDERSTORMS AT CHA AND TYS. EVEN THOUGH
UPPER RIDGE WILL REMAIN...SEVERE CONVECTION NEARING THE MISSISSIPPI RIVER
WILL SEND OUT AN OUTFLOW BOUNDARY ACROSS THE TENNESSEE VALLEY TODAY.

THIS BOUNDARY ALONG WITH LOCAL TERRAIN FEATURES WILL PRODUCE
THUNDERSTORMS NEAR THE CHA/TYS TERMINALS BETWEEN 19-23Z. WINDS WILL
BE SOUTH TO SOUTHWEST DURING THE DAY TODAY BETWEEN 8-14KTS..EXCEPT
IN/NEAR STORMS.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

000
FXUS64 KOHX 210502
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1202 AM CDT TUE MAY 21 2013

.UPDATE...

&&

.AVIATION...
06Z TAFS...SOME MVFR BR OR PERHAPS PATCHY STRATUS IS POSSIBLE
OVERNIGHT. STORMS OVER AR/MO WILL APPROACH FROM THE WEST...BUT
THINK THEY WILL MOSTLY DIMINISH BEFORE REACHING MID TN. S WINDS
WILL BECOME SOMEWHAT GUSTY ON TUESDAY...TO 20KT AT
TIMES...ESPECIALLY FOR CKV. THE CHANCE FOR TSRA WILL INCREASE LATE
IN THE TAF PERIOD WITH AN APPROACHING DISTURBANCE. SCT
COVERAGE...SO JUST INCLUDING A VCTS FOR CKV/BNA.

13

&&

.PREV DISCUSSION... /ISSUED 854 PM CDT MON MAY 20 2013/

UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT CLEAR SKIES
ACROSS THE MID STATE THRU THE EVENING HRS...WITH A GENERAL INCREASE
OF CLOUDINESS WEST TO EAST ACROSS THE MID STATE AFTER MIDNIGHT. HAVE
ALSO MENTIONED PATCHY FOG AFTER MIDNIGHT PLATEAU PER CONTINUED LOW
LEVEL MOISTURE POOLING POTENTIAL. WITH SOME UNCERTAINTIES CONCERNING
ACTUAL CLOUD COVERAGE LATE...WILL CONTINUE TO GO CLOSE TO CURRENT
FORECAST REASONING ON OVERNIGHT LOWS.


PREV DISCUSSION... /ISSUED 324 PM CDT MON MAY 20 2013/

AFTERNOON CU DEVELOPMENT IS WIDESPREAD ACROSS THE MID STATE THIS
AFTERNOON AS DEWPOINTS HAVE CONTINUED TO RISE. MID LEVEL CAP IS
RATHER STRONG ACCORDING TO THE 12Z SOUNDING FROM THIS MORNING. THE
HIGHER DEWPOINTS HAVE ACTED TO LOWER CONVECTIVE TEMPS BUT CURRENT
TEMPS ARE STRUGGLING TO RISE GIVEN THE EXTRA CLOUD COVER.

FOR TONIGHT`S FORECAST...WILL INCLUDE A 20 POP BUT ONLY FOR THE
NW. THIS IS IN LINE WITH THE HRRR REFLECTIVITY FCST WHICH SHOWS
LITTLE IF ANY DEVELOPMENT. OVERALL...IT JUST APPEARS THAT THERE IS
TOO MUCH VERTICAL DRYNESS IN PLACE.

A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL BE IN THE FCST AGAIN FOR
TUESDAY. MOISTURE LEVELS SHOULD BE HIGHER AND WE DO SEE MORE 18Z CAP
EROSION WITH THE GFS MODEL. THE INCREASE IN MOISTURE WILL BE AIDED
BY AN APPROACHING FRONTAL BOUNDARY WHICH WILL IMPACT THE AREA LATE
TUESDAY NIGHT AND INTO WEDNESDAY. AT THAT TIME...A SLIGHT RISK OF
SEVERE WEATHER IS IN THE FCST FOR OUR NW COUNTIES. BEST OMEGA
FORCING APPEARS TO BE AROUND 06Z WEDNESDAY ACROSS WESTERN TN.
BUT...THERE COULD BE A FEW STRONGER CELLS OVER THAT SAME AREA
EARLIER ON TUES AFTERNOON. STORM MOTION SHOULD RUN FROM SW TO NE.

SHOWERS AND TSTMS TO PERSIST INTO WEDNESDAY. ITS IMPORTANT TO NOTE
HOWEVER THAT OVERALL POPS WITH THIS SYSTEM ARE NOT DRASTICALLY HIGH.
IN FACT...MODELS NOT LEANING TOWARD DEEP MOISTURE WITH A WIDESPREAD
AREA OF RAIN OCCURRING. NEVERTHELESS...POPS IN THE 40-60 PERCENT
RANGE WILL BE INCLUDED FOR TUESDAY NT INTO WEDNESDAY. AFTER A FEW
LINGERING SHOWERS ON THURSDAY ACROSS THE PLATEAU...CLEARING WILL
OCCUR WITH DRIER AIR MOVING IN.

FOR THE NEAR TERM TEMPS...WILL AGAIN UNDERCUT THE HIGH TEMPS FOR
TUESDAY AND WEDNESDAY. OVERNIGHT LOWS FROM THE GUIDANCE APPEARS
REASONABLE.

IN THE EXT FCST...NICE LATE MAY CONDITIONS ARE ON TAP FOLLOWING THE
FROPA WHICH WAS MENTIONED IN THE SHORT TERM TIME FRAME.
THUS...SUNSHINE TO RETURN IN EARNEST FOR FRIDAY AND INTO THE
WEEKEND. THERMAL TROUGHING WILL BE SLOW TO GIVE WAY AND
THUS...MOSTLY SUNNY SKIES WITH BELOW NORMAL TEMPS AND LOWER
HUMIDITY LEVELS WILL PREVAIL THU THROUGH SAT. SUNDAY AND MONDAY...UPPER
RIDGING AND HEIGHT RISES WILL BE ON TAP. THIS WILL EQUATE TO HIGH
TEMPS BACK UP INTO THE 80S. BUT...STILL NOT SEEING ANY APPRECIABLE
PRECIP CHANCES THROUGH MONDAY.

21

&&

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

&&

$$

000
FXUS64 KMEG 210435
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1135 PM CDT MON MAY 20 2013

.DISCUSSION...

UPDATED FOR 06Z AVIATION DISCUSSION

&&

.PREV DISCUSSION... /ISSUED 836 PM CDT MON MAY 20 2013/

UPDATE...

LINE OF SEVERE THUNDERSTORMS CURRENTLY MOVING THROUGH SOUTHWEST
MISSOURI AND NORTHWEST ARKANSAS SHOULD PUSH INTO RANDOLPH AND
LAWRENCE COUNTIES BETWEEN 10-11 PM CDT. LINE SHOULD WEAKEN SOME BY
THE TIME IT REACHES NORTHEAST ARKANSAS DUE TO THE LOSS OF DAYTIME
HEATING. HOWEVER...THERE WILL STILL MAY BE A FEW STRONG TO SEVERE
THUNDERSTORMS THAT MAY OCCUR. WILL UPDATE TO BUMP UP POPS. UPDATE
WILL BE OUT SHORTLY.

KRM

DISCUSSION... /ISSUED 324 PM CDT MON MAY 20 2013/

TONIGHT THROUGH WEDNESDAY...

FAIRLY DECENT MODEL AGREEMENT THROUGH THE SHORT TERM...WITH JUST
SOME ISSUES RESOLVING THE CONVECTION THAT IS DEVELOPING OFF TO THE
WEST AND HOW IT WILL MOVE THIS WAY TONIGHT...AND AGAIN TOMORROW.
NOT ENOUGH DIFFERENCES TO LOWER FORECAST CONFIDENCE TOO
MUCH...REMAINS ABOVE AVERAGE. RIDGING LOOKS TO CONTINUE TO HOLD ON
THROUGH THE EVENING WITH THE SOUTHERLY FLOW CONTINUING TO PULL
MOIST GULF AIR INTO THE MIDSOUTH. CONVECTION OFF TO THE WEST MAY
ORGANIZE THIS EVENING AND MAKE A RUN AT THE REGION LATE
TONIGHT...PUSHING INTO THE NW HALF OF THE FORECAST AREA...THOUGH
WEAKENING DRAMATICALLY AS IT PUSHES INTO THE RIDGE. LITTLE IF ANY
SEVERE WEATHER THREAT. CLOUDS LEFT BEHIND WILL LIMIT HEATING SOME
AND LIKELY DAMPEN THE ENVIRONMENTS ABILITY TO DESTABILIZE
SUFFICIENTLY FOR SEVERE STORMS. SOME SCTD SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AND INCREASE IN COVERAGE FROM THE
WEST DURING THE LATE AFTERNOON INTO THE EVENING AND
OVERNIGHT...ESPECIALLY AFTER WED 00Z. SEVERE STORM CHANCES SEEM
SMALL DUE TO SOME LIMITING FACTORS SUCH AS THE TIME OF DAY THE
BULK OF THE STORMS WILL REACH THE REGION...MODEST
INSTABILITY...AND NOT TOO IMPRESSIVE LAPSE RATES ACCORDING TO THE
LATEST SOUNDINGS. GUSTY WINDS AND MODERATE TO HEAVY RAINFALL WILL
BE VERY LIKELY. FRONT WILL PUSH THROUGH THE REGION WEDNESDAY WITH
THE SHOWERS AND THUNDERSTORMS EXITING THE AREA BY LATE IN THE DAY
FOR MUCH...IF NOT ALL OF THE REGION. -ABS

THURSDAY THROUGH SUNDAY...

DRIER AND COOLER AIR WILL WORK INTO THE REGION BEHIND THE FRONT AS
SURFACE HIGH NUDGES INTO THE MIDSOUTH. EACH DAY SHOULD BE DRY
THROUGH SUNDAY...WITH SLIGHTLY BELOW NORMAL OR NORMAL TEMPS
THURSDAY THROUGH SATURDAY...AND WARMING SUNDAY WITH A SOUTHERLY
PUSH OF WARMER AND MORE MOIST AIR FROM THE GULF AS RIDGING EXPANDS
ACROSS THE REGION. POSSIBLE RETURN OF DIURNAL SHOWERS AND THUNDERSTORMS
EARLY NEXT WEEK. -ABS

&&

.AVIATION...

06Z TAF CYCLE

A WEAKENING LINE OF SHRAS AND TSRAS WILL PUSH INTO WESTERN PARTS OF THE
MIDSOUTH OVERNIGHT. EXPECT THE LINE TO HOLD TOGETHER AND REACH
KJBR AFT 21/08Z AND GLANCE KMEM AFT 21/10Z. KMKL AND KTUP WILL
REMAIN VFR FOR THE REMAINDER OF THE NIGHT. EXPECT SOME LEFTOVER
SHRAS AND PATCHY MVFR CIGS TUESDAY MORNING. ANY LOWER CONDS WILL
IMPROVE TO VFR BY MIDDAY TUESDAY. EXPECT ANOTHER ROUND OF SHRAS AND
TSRA TO DEVELOP AND START TO IMPACT WESTERN AREAS OF THE MIDSOUTH
LATE TUESDAY AFTN INTO TUESDAY EVENING. ADDED TEMPOS FOR TSRAS AT
KJBR...KMEM AND KMKL FOR TUESDAY EVENING.

SOUTH WINDS AT 6-10 KTS TONIGHT...INCREASING TO 12-14 KTS WITH
HIGHER GUSTS BY TUESDAY AFTN.

SJM

&&

.AVIATION...


&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  74  88  70  83 /  10  30  80  50
MKL  71  85  69  82 /  10  30  70  50
JBR  70  84  66  82 /  60  60  80  30
TUP  70  88  69  82 /  10  20  50  60

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KOHX 210154 AAA
AFDOHX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NASHVILLE TN
854 PM CDT MON MAY 20 2013

.UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT CLEAR SKIES
ACROSS THE MID STATE THRU THE EVENING HRS...WITH A GENERAL INCREASE
OF CLOUDINESS WEST TO EAST ACROSS THE MID STATE AFTER MIDNIGHT. HAVE
ALSO MENTIONED PATCHY FOG AFTER MIDNIGHT PLATEAU PER CONTINUED LOW
LEVEL MOISTURE POOLING POTENTIAL. WITH SOME UNCERTAINTIES CONCERNING
ACTUAL CLOUD COVERAGE LATE...WILL CONTINUE TO GO CLOSE TO CURRENT
FORECAST REASONING ON OVERNIGHT LOWS.
&&

.PREV DISCUSSION.../ISSUED 603 PM CDT MON MAY 20 2013/

UPDATE...FOR AVIATION.

AVIATION...
00Z TAFS...UPPER LEVEL RIDGE WILL CONTINUE TO BE THE MAIN
INFLUENCE WITH FAIR WX THROUGH THIS EVENING. SOME MVFR BR OR
PERHAPS PATCHY STRATUS IS POSSIBLE TOWARD DAYBREAK. S WINDS WILL
BECOME SOMEWHAT GUSTY ON TUESDAY...TO 20KT AT TIMES...ESPECIALLY
FOR CKV. THE RIDGE WILL BEGIN TO MOVE EAST WITH AN APPROACHING
DISTURBANCE BRINGING A CHANCE FOR TSRA BY THE END OF THE PERIOD.
COVERAGE WILL BE GENERALLY ISOLD...BUT COVERAGE WILL BE INCREASING
FROM THE WEST...SO INCLUDING A VCTS FOR CKV AFTER 21Z.

13

PREV DISCUSSION... /ISSUED 324 PM CDT MON MAY 20 2013/

AFTERNOON CU DEVELOPMENT IS WIDESPREAD ACROSS THE MID STATE THIS
AFTERNOON AS DEWPOINTS HAVE CONTINUED TO RISE. MID LEVEL CAP IS
RATHER STRONG ACCORDING TO THE 12Z SOUNDING FROM THIS MORNING. THE
HIGHER DEWPOINTS HAVE ACTED TO LOWER CONVECTIVE TEMPS BUT CURRENT
TEMPS ARE STRUGGLING TO RISE GIVEN THE EXTRA CLOUD COVER.

FOR TONIGHT`S FORECAST...WILL INCLUDE A 20 POP BUT ONLY FOR THE
NW. THIS IS IN LINE WITH THE HRRR REFLECTIVITY FCST WHICH SHOWS
LITTLE IF ANY DEVELOPMENT. OVERALL...IT JUST APPEARS THAT THERE IS
TOO MUCH VERTICAL DRYNESS IN PLACE.

A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL BE IN THE FCST AGAIN FOR
TUESDAY. MOISTURE LEVELS SHOULD BE HIGHER AND WE DO SEE MORE 18Z CAP
EROSION WITH THE GFS MODEL. THE INCREASE IN MOISTURE WILL BE AIDED
BY AN APPROACHING FRONTAL BOUNDARY WHICH WILL IMPACT THE AREA LATE
TUESDAY NIGHT AND INTO WEDNESDAY. AT THAT TIME...A SLIGHT RISK OF
SEVERE WEATHER IS IN THE FCST FOR OUR NW COUNTIES. BEST OMEGA
FORCING APPEARS TO BE AROUND 06Z WEDNESDAY ACROSS WESTERN TN.
BUT...THERE COULD BE A FEW STRONGER CELLS OVER THAT SAME AREA
EARLIER ON TUES AFTERNOON. STORM MOTION SHOULD RUN FROM SW TO NE.

SHOWERS AND TSTMS TO PERSIST INTO WEDNESDAY. ITS IMPORTANT TO NOTE
HOWEVER THAT OVERALL POPS WITH THIS SYSTEM ARE NOT DRASTICALLY HIGH.
IN FACT...MODELS NOT LEANING TOWARD DEEP MOISTURE WITH A WIDESPREAD
AREA OF RAIN OCCURRING. NEVERTHELESS...POPS IN THE 40-60 PERCENT
RANGE WILL BE INCLUDED FOR TUESDAY NT INTO WEDNESDAY. AFTER A FEW
LINGERING SHOWERS ON THURSDAY ACROSS THE PLATEAU...CLEARING WILL
OCCUR WITH DRIER AIR MOVING IN.

FOR THE NEAR TERM TEMPS...WILL AGAIN UNDERCUT THE HIGH TEMPS FOR
TUESDAY AND WEDNESDAY. OVERNIGHT LOWS FROM THE GUIDANCE APPEARS
REASONABLE.

IN THE EXT FCST...NICE LATE MAY CONDITIONS ARE ON TAP FOLLOWING THE
FROPA WHICH WAS MENTIONED IN THE SHORT TERM TIME FRAME.
THUS...SUNSHINE TO RETURN IN EARNEST FOR FRIDAY AND INTO THE
WEEKEND. THERMAL TROUGHING WILL BE SLOW TO GIVE WAY AND
THUS...MOSTLY SUNNY SKIES WITH BELOW NORMAL TEMPS AND LOWER
HUMIDITY LEVELS WILL PREVAIL THU THROUGH SAT. SUNDAY AND MONDAY...UPPER
RIDGING AND HEIGHT RISES WILL BE ON TAP. THIS WILL EQUATE TO HIGH
TEMPS BACK UP INTO THE 80S. BUT...STILL NOT SEEING ANY APPRECIABLE
PRECIP CHANCES THROUGH MONDAY.

21

&&

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

$$
31

000
FXUS64 KMEG 210136
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
836 PM CDT MON MAY 20 2013

.UPDATE...

LINE OF SEVERE THUNDERSTORMS CURRENTLY MOVING THROUGH SOUTHWEST
MISSOURI AND NORTHWEST ARKANSAS SHOULD PUSH INTO RANDOLPH AND
LAWRENCE COUNTIES BETWEEN 10-11 PM CDT. LINE SHOULD WEAKEN SOME BY
THE TIME IT REACHES NORTHEAST ARKANSAS DUE TO THE LOSS OF DAYTIME
HEATING. HOWEVER...THERE WILL STILL MAY BE A FEW STRONG TO SEVERE
THUNDERSTORMS THAT MAY OCCUR. WILL UPDATE TO BUMP UP POPS. UPDATE
WILL BE OUT SHORTLY.

KRM

&&

.DISCUSSION... /ISSUED 324 PM CDT MON MAY 20 2013/

.TONIGHT THROUGH WEDNESDAY...

FAIRLY DECENT MODEL AGREEMENT THROUGH THE SHORT TERM...WITH JUST
SOME ISSUES RESOLVING THE CONVECTION THAT IS DEVELOPING OFF TO THE
WEST AND HOW IT WILL MOVE THIS WAY TONIGHT...AND AGAIN TOMORROW.
NOT ENOUGH DIFFERENCES TO LOWER FORECAST CONFIDENCE TOO
MUCH...REMAINS ABOVE AVERAGE. RIDGING LOOKS TO CONTINUE TO HOLD ON
THROUGH THE EVENING WITH THE SOUTHERLY FLOW CONTINUING TO PULL
MOIST GULF AIR INTO THE MIDSOUTH. CONVECTION OFF TO THE WEST MAY
ORGANIZE THIS EVENING AND MAKE A RUN AT THE REGION LATE
TONIGHT...PUSHING INTO THE NW HALF OF THE FORECAST AREA...THOUGH
WEAKENING DRAMATICALLY AS IT PUSHES INTO THE RIDGE. LITTLE IF ANY
SEVERE WEATHER THREAT. CLOUDS LEFT BEHIND WILL LIMIT HEATING SOME
AND LIKELY DAMPEN THE ENVIRONMENTS ABILITY TO DESTABILIZE
SUFFICIENTLY FOR SEVERE STORMS. SOME SCTD SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AND INCREASE IN COVERAGE FROM THE
WEST DURING THE LATE AFTERNOON INTO THE EVENING AND
OVERNIGHT...ESPECIALLY AFTER WED 00Z. SEVERE STORM CHANCES SEEM
SMALL DUE TO SOME LIMITING FACTORS SUCH AS THE TIME OF DAY THE
BULK OF THE STORMS WILL REACH THE REGION...MODEST
INSTABILITY...AND NOT TOO IMPRESSIVE LAPSE RATES ACCORDING TO THE
LATEST SOUNDINGS. GUSTY WINDS AND MODERATE TO HEAVY RAINFALL WILL
BE VERY LIKELY. FRONT WILL PUSH THROUGH THE REGION WEDNESDAY WITH
THE SHOWERS AND THUNDERSTORMS EXITING THE AREA BY LATE IN THE DAY
FOR MUCH...IF NOT ALL OF THE REGION. -ABS

.THURSDAY THROUGH SUNDAY...

DRIER AND COOLER AIR WILL WORK INTO THE REGION BEHIND THE FRONT AS
SURFACE HIGH NUDGES INTO THE MIDSOUTH. EACH DAY SHOULD BE DRY
THROUGH SUNDAY...WITH SLIGHTLY BELOW NORMAL OR NORMAL TEMPS
THURSDAY THROUGH SATURDAY...AND WARMING SUNDAY WITH A SOUTHERLY
PUSH OF WARMER AND MORE MOIST AIR FROM THE GULF AS RIDGING EXPANDS
ACROSS THE REGION. POSSIBLE RETURN OF DIURNAL SHOWERS AND THUNDERSTORMS
EARLY NEXT WEEK. -ABS

&&

.AVIATION...

00Z TAF CYCLE

VFR CONDS WILL PREVAIL THROUGH MOST OF THE OVERNIGHT HOURS. AT
LEAST PATCHY STRATUS WILL RETURN EARLY TUESDAY MORNING WHICH WILL
GRADUALLY LIFT WITH CONDS BECOMING VFR AGAIN BY 21/16Z. SHRAS AND
TSRAS MAY APPROACH KJBR LATER TONIGHT AND EARLY TUESDAY SO CONTIUED
VCTS THERE. EXPECT ANOTHER ROUND OF SHRAS AND TSRA TO DEVELOP AND
START TO IMPACT WESTERN AREAS OF THE MIDSOUTH TUESDAY AFTN. FOR
NOW WENT WITH VCTS AT KJBR AND KMEM AFT 21/20Z.

SOUTH WINDS OF 8-12 KTS TONIGHT...INCREASING TO 12-14 KTS WITH
HIGHER GUSTS TUESDAY AFTN.

SJM

&&


&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  74  88  70  83 /  10  30  80  50
MKL  71  85  69  82 /  10  30  70  50
JBR  70  84  66  82 /  40  60  80  30
TUP  70  88  69  82 /  10  20  50  60

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMRX 210115 AAB
AFDMRX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
915 PM EDT MON MAY 20 2013

.DISCUSSION...
MINOR TWEAKS MADE TO THE FORECAST THIS EVENING AS MOST EVERYTHING
APPEARS TO BE ON TRACK. GIVEN THE LATEST OBS/TRENDS...OPTED TO
REMOVE THE LOW-END MENTIONABLE POPS FROM THE FAR NORTHEAST AND
MOUNTAIN ZONES AS ALL CONVECTION HAS REMAINED EAST OF THE MOUNTAINS
IN NC AND IS DISSIPATING WITH THE LOSS OF DAYTIME HEATING. GIVEN
THE MOIST BOUNDARY LAYER CONDITIONS AND CALM WINDS...THE POTENTIAL
FOR AREAS OF FOG TO FORM /ESPECIALLY IN THE USUAL FOG-PRONE AREAS/
SEEMS REASONABLE AS HAVE ADDED A MENTION OF THIS AFTER 08Z. ALSO
LOWERED TEMPERATURES A DEGREE OR SO GIVEN THE EXPECTED CLEARER
CONDITIONS WHICH SHOULD RESULT SOME SLIGHTLY BETTER RADIATIONAL
COOLING.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             66  90  67  83  63 /  10  20  20  70  40
KNOXVILLE MCGHEE TYSON AIRPORT, TN  64  88  67  83  64 /  10  20  20  60  40
OAK RIDGE, TN                       64  88  65  83  62 /  10  20  20  70  40
TRI CITIES AIRPORT, TN              59  86  60  82  60 /  10  30  20  60  40

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

AMP

000
FXUS64 KMEG 202326
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
626 PM CDT MON MAY 20 2013

.DISCUSSION...

UPDATED FOR 00Z AVIATION DISCUSSION

&&

.PREV DISCUSSION... /ISSUED 324 PM CDT MON MAY 20 2013/

DISCUSSION...

TONIGHT THROUGH WEDNESDAY...

FAIRLY DECENT MODEL AGREEMENT THROUGH THE SHORT TERM...WITH JUST
SOME ISSUES RESOLVING THE CONVECTION THAT IS DEVELOPING OFF TO THE
WEST AND HOW IT WILL MOVE THIS WAY TONIGHT...AND AGAIN TOMORROW.
NOT ENOUGH DIFFERENCES TO LOWER FORECAST CONFIDENCE TOO
MUCH...REMAINS ABOVE AVERAGE. RIDGING LOOKS TO CONTINUE TO HOLD ON
THROUGH THE EVENING WITH THE SOUTHERLY FLOW CONTINUING TO PULL
MOIST GULF AIR INTO THE MIDSOUTH. CONVECTION OFF TO THE WEST MAY
ORGANIZE THIS EVENING AND MAKE A RUN AT THE REGION LATE
TONIGHT...PUSHING INTO THE NW HALF OF THE FORECAST AREA...THOUGH
WEAKENING DRAMATICALLY AS IT PUSHES INTO THE RIDGE. LITTLE IF ANY
SEVERE WEATHER THREAT. CLOUDS LEFT BEHIND WILL LIMIT HEATING SOME
AND LIKELY DAMPEN THE ENVIRONMENTS ABILITY TO DESTABILIZE
SUFFICIENTLY FOR SEVERE STORMS. SOME SCTD SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AND INCREASE IN COVERAGE FROM THE
WEST DURING THE LATE AFTERNOON INTO THE EVENING AND
OVERNIGHT...ESPECIALLY AFTER WED 00Z. SEVERE STORM CHANCES SEEM
SMALL DUE TO SOME LIMITING FACTORS SUCH AS THE TIME OF DAY THE
BULK OF THE STORMS WILL REACH THE REGION...MODEST
INSTABILITY...AND NOT TOO IMPRESSIVE LAPSE RATES ACCORDING TO THE
LATEST SOUNDINGS. GUSTY WINDS AND MODERATE TO HEAVY RAINFALL WILL
BE VERY LIKELY. FRONT WILL PUSH THROUGH THE REGION WEDNESDAY WITH
THE SHOWERS AND THUNDERSTORMS EXITING THE AREA BY LATE IN THE DAY
FOR MUCH...IF NOT ALL OF THE REGION. -ABS

THURSDAY THROUGH SUNDAY...

DRIER AND COOLER AIR WILL WORK INTO THE REGION BEHIND THE FRONT AS
SURFACE HIGH NUDGES INTO THE MIDSOUTH. EACH DAY SHOULD BE DRY
THROUGH SUNDAY...WITH SLIGHTLY BELOW NORMAL OR NORMAL TEMPS
THURSDAY THROUGH SATURDAY...AND WARMING SUNDAY WITH A SOUTHERLY
PUSH OF WARMER AND MORE MOIST AIR FROM THE GULF AS RIDGING EXPANDS
ACROSS THE REGION. POSSIBLE RETURN OF DIURNAL SHOWERS AND THUNDERSTORMS
EARLY NEXT WEEK. -ABS

&&

.AVIATION...

00Z TAF CYCLE

VFR CONDS WILL PREVAIL THROUGH MOST OF THE OVERNIGHT HOURS. AT
LEAST PATCHY STRATUS WILL RETURN EARLY TUESDAY MORNING WHICH WILL
GRADUALLY LIFT WITH CONDS BECOMING VFR AGAIN BY 21/16Z. SHRAS AND
TSRAS MAY APPROACH KJBR LATER TONIGHT AND EARLY TUESDAY SO CONTIUED
VCTS THERE. EXPECT ANOTHER ROUND OF SHRAS AND TSRA TO DEVELOP AND
START TO IMPACT WESTERN AREAS OF THE MIDSOUTH TUESDAY AFTN. FOR
NOW WENT WITH VCTS AT KJBR AND KMEM AFT 21/20Z.

SOUTH WINDS OF 8-12 KTS TONIGHT...INCREASING TO 12-14 KTS WITH
HIGHER GUSTS TUESDAY AFTN.

SJM

&&


.PRELIMINARY POINT TEMPS/POPS...
MEM  74  88  70  83 /  10  30  80  50
MKL  71  85  69  82 /  10  30  70  50
JBR  70  84  66  82 /  40  60  80  30
TUP  70  88  69  82 /  10  20  50  60

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMRX 202315 AAA
AFDMRX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
715 PM EDT MON MAY 20 2013

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT EACH TERMINAL THROUGH THE REMAINDER
OF THE EVENING THROUGH LATE TONIGHT BEFORE VIS DROP TO MVFR LEVELS
FROM SOME LIGHT FOG. THE FOG WILL DISSIPATE AFTER SUNRISE...
RESULTING IN A RETURN TO VFR CONDITIONS THROUGH THE REMINDER OF THE
PERIOD.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

AMP

000
FXUS64 KOHX 202303
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
603 PM CDT MON MAY 20 2013

.UPDATE...FOR AVIATION.

&&

.AVIATION...
00Z TAFS...UPPER LEVEL RIDGE WILL CONTINUE TO BE THE MAIN
INFLUENCE WITH FAIR WX THROUGH THIS EVENING. SOME MVFR BR OR
PERHAPS PATCHY STRATUS IS POSSIBLE TOWARD DAYBREAK. S WINDS WILL
BECOME SOMEWHAT GUSTY ON TUESDAY...TO 20KT AT TIMES...ESPECIALLY
FOR CKV. THE RIDGE WILL BEGIN TO MOVE EAST WITH AN APPROACHING
DISTURBANCE BRINGING A CHANCE FOR TSRA BY THE END OF THE PERIOD.
COVERAGE WILL BE GENERALLY ISOLD...BUT COVERAGE WILL BE INCREASING
FROM THE WEST...SO INCLUDING A VCTS FOR CKV AFTER 21Z.

13

&&

.PREV DISCUSSION... /ISSUED 324 PM CDT MON MAY 20 2013/

AFTERNOON CU DEVELOPMENT IS WIDESPREAD ACROSS THE MID STATE THIS
AFTERNOON AS DEWPOINTS HAVE CONTINUED TO RISE. MID LEVEL CAP IS
RATHER STRONG ACCORDING TO THE 12Z SOUNDING FROM THIS MORNING. THE
HIGHER DEWPOINTS HAVE ACTED TO LOWER CONVECTIVE TEMPS BUT CURRENT
TEMPS ARE STRUGGLING TO RISE GIVEN THE EXTRA CLOUD COVER.

FOR TONIGHT`S FORECAST...WILL INCLUDE A 20 POP BUT ONLY FOR THE
NW. THIS IS IN LINE WITH THE HRRR REFLECTIVITY FCST WHICH SHOWS
LITTLE IF ANY DEVELOPMENT. OVERALL...IT JUST APPEARS THAT THERE IS
TOO MUCH VERTICAL DRYNESS IN PLACE.

A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL BE IN THE FCST AGAIN FOR
TUESDAY. MOISTURE LEVELS SHOULD BE HIGHER AND WE DO SEE MORE 18Z CAP
EROSION WITH THE GFS MODEL. THE INCREASE IN MOISTURE WILL BE AIDED
BY AN APPROACHING FRONTAL BOUNDARY WHICH WILL IMPACT THE AREA LATE
TUESDAY NIGHT AND INTO WEDNESDAY. AT THAT TIME...A SLIGHT RISK OF
SEVERE WEATHER IS IN THE FCST FOR OUR NW COUNTIES. BEST OMEGA
FORCING APPEARS TO BE AROUND 06Z WEDNESDAY ACROSS WESTERN TN.
BUT...THERE COULD BE A FEW STRONGER CELLS OVER THAT SAME AREA
EARLIER ON TUES AFTERNOON. STORM MOTION SHOULD RUN FROM SW TO NE.

SHOWERS AND TSTMS TO PERSIST INTO WEDNESDAY. ITS IMPORTANT TO NOTE
HOWEVER THAT OVERALL POPS WITH THIS SYSTEM ARE NOT DRASTICALLY HIGH.
IN FACT...MODELS NOT LEANING TOWARD DEEP MOISTURE WITH A WIDESPREAD
AREA OF RAIN OCCURRING. NEVERTHELESS...POPS IN THE 40-60 PERCENT
RANGE WILL BE INCLUDED FOR TUESDAY NT INTO WEDNESDAY. AFTER A FEW
LINGERING SHOWERS ON THURSDAY ACROSS THE PLATEAU...CLEARING WILL
OCCUR WITH DRIER AIR MOVING IN.

FOR THE NEAR TERM TEMPS...WILL AGAIN UNDERCUT THE HIGH TEMPS FOR
TUESDAY AND WEDNESDAY. OVERNIGHT LOWS FROM THE GUIDANCE APPEARS
REASONABLE.

IN THE EXT FCST...NICE LATE MAY CONDITIONS ARE ON TAP FOLLOWING THE
FROPA WHICH WAS MENTIONED IN THE SHORT TERM TIME FRAME.
THUS...SUNSHINE TO RETURN IN EARNEST FOR FRIDAY AND INTO THE
WEEKEND. THERMAL TROUGHING WILL BE SLOW TO GIVE WAY AND
THUS...MOSTLY SUNNY SKIES WITH BELOW NORMAL TEMPS AND LOWER
HUMIDITY LEVELS WILL PREVAIL THU THROUGH SAT. SUNDAY AND MONDAY...UPPER
RIDGING AND HEIGHT RISES WILL BE ON TAP. THIS WILL EQUATE TO HIGH
TEMPS BACK UP INTO THE 80S. BUT...STILL NOT SEEING ANY APPRECIABLE
PRECIP CHANCES THROUGH MONDAY.

21

&&

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

&&

$$

000
FXUS64 KOHX 202024
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
324 PM CDT MON MAY 20 2013

DISCUSSION...
AFTERNOON CU DEVELOPMENT IS WIDESPREAD ACROSS THE MID STATE THIS
AFTERNOON AS DEWPOINTS HAVE CONTINUED TO RISE. MID LEVEL CAP IS
RATHER STRONG ACCORDING TO THE 12Z SOUNDING FROM THIS MORNING. THE
HIGHER DEWPOINTS HAVE ACTED TO LOWER CONVECTIVE TEMPS BUT CURRENT
TEMPS ARE STRUGGLING TO RISE GIVEN THE EXTRA CLOUD COVER.

FOR TONIGHT`S FORECAST...WILL INCLUDE A 20 POP BUT ONLY FOR THE
NW. THIS IS IN LINE WITH THE HRRR REFLECTIVITY FCST WHICH SHOWS
LITTLE IF ANY DEVELOPMENT. OVERALL...IT JUST APPEARS THAT THERE IS
TOO MUCH VERTICAL DRYNESS IN PLACE.

A SLIGHT CHANCE OF SHOWERS AND TSTMS WILL BE IN THE FCST AGAIN FOR
TUESDAY. MOISTURE LEVELS SHOULD BE HIGHER AND WE DO SEE MORE 18Z CAP
EROSION WITH THE GFS MODEL. THE INCREASE IN MOISTURE WILL BE AIDED
BY AN APPROACHING FRONTAL BOUNDARY WHICH WILL IMPACT THE AREA LATE
TUESDAY NIGHT AND INTO WEDNESDAY. AT THAT TIME...A SLIGHT RISK OF
SEVERE WEATHER IS IN THE FCST FOR OUR NW COUNTIES. BEST OMEGA
FORCING APPEARS TO BE AROUND 06Z WEDNESDAY ACROSS WESTERN TN.
BUT...THERE COULD BE A FEW STRONGER CELLS OVER THAT SAME AREA
EARLIER ON TUES AFTERNOON. STORM MOTION SHOULD RUN FROM SW TO NE.

SHOWERS AND TSTMS TO PERSIST INTO WEDNESDAY. ITS IMPORTANT TO NOTE
HOWEVER THAT OVERALL POPS WITH THIS SYSTEM ARE NOT DRASTICALLY HIGH.
IN FACT...MODELS NOT LEANING TOWARD DEEP MOISTURE WITH A WIDESPREAD
AREA OF RAIN OCCURRING. NEVERTHELESS...POPS IN THE 40-60 PERCENT
RANGE WILL BE INCLUDED FOR TUESDAY NT INTO WEDNESDAY. AFTER A FEW
LINGERING SHOWERS ON THURSDAY ACROSS THE PLATEAU...CLEARING WILL
OCCUR WITH DRIER AIR MOVING IN.

FOR THE NEAR TERM TEMPS...WILL AGAIN UNDERCUT THE HIGH TEMPS FOR
TUESDAY AND WEDNESDAY. OVERNIGHT LOWS FROM THE GUIDANCE APPEARS
REASONABLE.

IN THE EXT FCST...NICE LATE MAY CONDITIONS ARE ON TAP FOLLOWING THE
FROPA WHICH WAS MENTIONED IN THE SHORT TERM TIME FRAME.
THUS...SUNSHINE TO RETURN IN EARNEST FOR FRIDAY AND INTO THE
WEEKEND. THERMAL TROUGHING WILL BE SLOW TO GIVE WAY AND
THUS...MOSTLY SUNNY SKIES WITH BELOW NORMAL TEMPS AND LOWER
HUMIDITY LEVELS WILL PREVAIL THU THROUGH SAT. SUNDAY AND MONDAY...UPPER
RIDGING AND HEIGHT RISES WILL BE ON TAP. THIS WILL EQUATE TO HIGH
TEMPS BACK UP INTO THE 80S. BUT...STILL NOT SEEING ANY APPRECIABLE
PRECIP CHANCES THROUGH MONDAY.

.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE      68  89  67  82 /  05  20  50  70
CLARKSVILLE    68  87  65  82 /  10  30  60  50
CROSSVILLE     64  85  65  77 /  10  30  40  70
COLUMBIA       68  89  67  82 /  05  20  40  60
LAWRENCEBURG   66  88  67  82 /  05  20  40  60
WAVERLY        68  87  66  82 /  10  30  60  50

&&

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

$$

21

000
FXUS64 KMEG 202024
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
324 PM CDT MON MAY 20 2013

.DISCUSSION...

TONIGHT THROUGH WEDNESDAY...

FAIRLY DECENT MODEL AGREEMENT THROUGH THE SHORT TERM...WITH JUST
SOME ISSUES RESOLVING THE CONVECTION THAT IS DEVELOPING OFF TO THE
WEST AND HOW IT WILL MOVE THIS WAY TONIGHT...AND AGAIN TOMORROW.
NOT ENOUGH DIFFERENCES TO LOWER FORECAST CONFIDENCE TOO
MUCH...REMAINS ABOVE AVERAGE. RIDGING LOOKS TO CONTINUE TO HOLD ON
THROUGH THE EVENING WITH THE SOUTHERLY FLOW CONTINUING TO PULL
MOIST GULF AIR INTO THE MIDSOUTH. CONVECTION OFF TO THE WEST MAY
ORGANIZE THIS EVENING AND MAKE A RUN AT THE REGION LATE
TONIGHT...PUSHING INTO THE NW HALF OF THE FORECAST AREA...THOUGH
WEAKENING DRAMATICALLY AS IT PUSHES INTO THE RIDGE. LITTLE IF ANY
SEVERE WEATHER THREAT. CLOUDS LEFT BEHIND WILL LIMIT HEATING SOME
AND LIKELY DAMPEN THE ENVIRONMENTS ABILITY TO DESTABILIZE
SUFFICIENTLY FOR SEVERE STORMS. SOME SCTD SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AND INCREASE IN COVERAGE FROM THE
WEST DURING THE LATE AFTERNOON INTO THE EVENING AND
OVERNIGHT...ESPECIALLY AFTER WED 00Z. SEVERE STORM CHANCES SEEM
SMALL DUE TO SOME LIMITING FACTORS SUCH AS THE TIME OF DAY THE
BULK OF THE STORMS WILL REACH THE REGION...MODEST
INSTABILITY...AND NOT TOO IMPRESSIVE LAPSE RATES ACCORDING TO THE
LATEST SOUNDINGS. GUSTY WINDS AND MODERATE TO HEAVY RAINFALL WILL
BE VERY LIKELY. FRONT WILL PUSH THROUGH THE REGION WEDNESDAY WITH
THE SHOWERS AND THUNDERSTORMS EXITING THE AREA BY LATE IN THE DAY
FOR MUCH...IF NOT ALL OF THE REGION. -ABS

THURSDAY THROUGH SUNDAY...

DRIER AND COOLER AIR WILL WORK INTO THE REGION BEHIND THE FRONT AS
SURFACE HIGH NUDGES INTO THE MIDSOUTH. EACH DAY SHOULD BE DRY
THROUGH SUNDAY...WITH SLIGHTLY BELOW NORMAL OR NORMAL TEMPS
THURSDAY THROUGH SATURDAY...AND WARMING SUNDAY WITH A SOUTHERLY
PUSH OF WARMER AND MORE MOIST AIR FROM THE GULF AS RIDGING EXPANDS
ACROSS THE REGION. POSSIBLE RETURN OF DIURNAL SHOWERS AND THUNDERSTORMS
EARLY NEXT WEEK. -ABS

&&

.AVIATION...

18Z TAF CYCLE

MID LEVEL CLOUDS WILL REMAIN ACROSS THE MIDSOUTH TODAY...GENERALLY
3000-4000 FT. WE WILL LIKELY SEE CIGS BECOME SCT AFTER
SUNSET...BUT ADDITIONAL LOW TO MID LEVEL CLOUDS WILL RETURN TOWARD
MORNING. SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE
TOMORROW...BUT NOT LIKELY MAKE IT TO MEM...MKL...OR TUP BEFORE
18Z. WILL CARRY VCTS AT JBR AFTER 11Z. MVFR CIGS ARE EXPECTED AT
ALL SITES TOMORROW. WINDS WILL REMAIN SOUTHERLY...GENERALLY AROUND
10 KNOTS WITH GUSTS IN EXCESS OF 20 KTS...STRONGEST AT JBR.

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  74  88  70  83 /  10  30  80  50
MKL  71  85  69  82 /  10  30  70  50
JBR  70  84  66  82 /  40  60  80  30
TUP  70  88  69  82 /  10  20  50  60

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMRX 201856
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
255 PM EDT MON MAY 20 2013

.SHORT TERM (TONIGHT AND TUESDAY)...THOUGH A FEW THUNDERSTORMS WILL
BE POSSIBLE TONIGHT OVER THE EAST TN MOUNTAINS...THE BULK OF THE
AREA WILL REMAIN DRY AS AN UPPER RIDGE CONTINUES TO BUILD IN.  ON
TUESDAY...WARM...MOIST AND WEAKLY UNSTABLE AIR OVER THE REGION WILL
WILL ALLOW FOR DIURNAL CONVECTION TO DEVELOP DURING THE AFTERNOON.
THIS ACTIVITY SHOULD INITIATE OVER HIGHER ELEVATIONS WITH ONLY A FEW
MOVING INTO THE VALLEY LATE IN THE DAY.

.LONG TERM (WEDNESDAY THROUGH MONDAY)...WETTEST PERIODS OF THE LONG
TERM STILL LOOK TO BE WEDNESDAY AND WEDNESDAY NIGHT AHEAD OF AN
APPROACHING COLD FRONT. NUDGED POPS UP TO LIKELY BY NOON WEDNESDAY
ACROSS ALL OF THE FORECAST AREA...AND CARRIED 40 TO 50 PERCENT POPS
FOR WEDNESDAY EVENING WITH SCATTERED WORDING.

FRONTAL PASSAGE NOT LIKELY TO OCCUR UNTIL THURSDAY AFTERNOON OR
EVENING WITH CHANCE POPS NEEDED THROUGH ABOUT 12Z FRIDAY. A SURFACE
RIDGE OF HIGH PRESSURE THEN BEGINS TO BUILD SE THROUGH THE WEEKEND
WHILE UPPER LEVEL HEIGHTS ALSO RISE. 12Z GFSX MOS POPS ARE TRENDING
A LITTLE DRIER THAN THE 00Z GUIDANCE...BUT FOR NOW I KEPT IN LOW
TOKEN POPS BOTH FRIDAY AND FRIDAY NIGHT FOR POSSIBLE SPOTTY DIURNAL
CONVECTION.

FOR EARLY NEXT WEEK...A WARM FRONT APPEARS TO BE A FOCUS FOR SOME
CONVECTIVE PRECIPITATION TO OUR NW BY MONDAY...WITH 12Z GFS MODEL
SHOWING A SHORTWAVE MOVING THROUGH THE UPPER RIDGE AND SPREADING
CONVECTION SE INTO THE OHIO VALLEY AND TO THE SRN APPALACHIANS BY
MONDAY NIGHT. SOME LOW LEVEL SOUTHERLY FLOW DOES RETURN BY MONDAY
WHICH SUPPORTS AT LEAST SLIGHT CHANCE POPS FOR SPOTTY DIURNAL
CONVECTION.

12Z GFSX MOS TEMPS HAVE TRENDED A FEW DEGREES COOLER ON BOTH MAX AND
MIN TEMPS FROM THURSDAY THRU MONDAY. I STAYED A BIT CLOSER TO THE
00Z GFSX MOS TEMPS AND ADJACENT NWS GRIDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN   66  90  67  83  63 /  10  20  20  70  40
KNOXVILLE AIRPORT, TN     64  88  67  83  64 /  10  20  20  60  40
OAK RIDGE, TN             64  88  65  83  62 /  10  20  20  70  40
TRI CITIES AIRPORT, TN    61  86  60  82  60 /  10  30  20  60  40

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

MJB/TG

000
FXUS64 KOHX 201816
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
116 PM CDT MON MAY 20 2013

.UPDATE...FOR 18Z TAFS.

&&

.AVIATION...
SHALLOW LL MOISTURE REMAINS IN PLACE ACROSS THE MID-STATE WHILE
ML/UL RIDGE STAYS PUT NEXT 24HRS. FAIRLY WARM TEMPS HELPING TO
KEEP SCT-BKN STRATA-CU AROUND THE REGION...LARGELY ABV 3KFT.
MVFR VSBYS AND POSSIBLY CEILINGS EXPECTED TO DEVELOP EARLY
MORNING BUT WILL GO VFR 14-15Z TUE. ISOLD PCPN WILL BEGIN TO
SLIDE INTO THE NW LATER TUE. WINDS EXPECTED TO BE GUSTY THIS
AFTERNOON CKV/BNA.

&&

.PREV DISCUSSION... /ISSUED 942 AM CDT MON MAY 20 2013/

UPDATE...
DEWPOINTS ON THE INCREASE OVER THE LAST FEW HOURS. SHOULD SEE THE
TREND WHEREBY AN INCREASE IN CAPES AND DEWPOINTS CONTINUE INTO THE
AFTERNOON. NO REAL DYNAMICS TO SPEAK OF THOUGH AS THE BEST
ORGANIZED CONVECTION REMAINS OUT WEST ALONG THE CENTRAL PLAINS.
THAT ASSOCIATED FRONTAL BOUNDARY WILL REMAIN TO OUR WEST THROUGH
AT LEAST TODAY AND TONIGHT.

FOR THE UPDATE...WILL INCREASE SKY COVER IN GRIDS AS WELL AS LOWER
TEMPS A DEGREE OR TWO. LATEST MAV GUIDANCE HAS BACKED OFF A FEW
DEGREES AS MORE IN THE WAY OF CLOUD COVER IS EXPECTED.

OTW...NO OTHER CHANGES...ISOLATED AFT SHOWERS AND TSTMS ARE IN THE
GRIDS AND THAT LOOKS SUFFICIENT.

PREV DISCUSSION... /ISSUED 626 AM CDT MON MAY 20 2013/

UPDATE...

12Z TAF DISCUSSION.

AVIATION...

IR SATELLITE IMAGERY SHOWS LOW CLOUDS HAVE VERY RAPIDLY ADVECTED
NORTHWARD INTO THE CENTRAL MID STATE PAST HOUR WITH MVFR CIGS NOW
AT BNA. COULD ALSO SEE MVFR CIGS AT CKV BRIEFLY THIS MORNING...BUT
BOTH BNA/CKV EXPECTED TO BECOME VFR BY LATE MORNING. PATCHY FOG
HAS RESULTED IN OCCASIONAL VIS RESTRICTIONS OVERNIGHT...BUT
EXPECTED TO IMPROVE TO VFR VIS AREAWIDE BY 14Z. OTHERWISE...EXPECT
SCATTERED CU THIS AFTERNOON WITH SOUTH TO SOUTHWEST WINDS 5 TO 11
KTS. AN ISOLATED -SHRA/-TSRA IS POSSIBLE THIS AFTERNOON
ESPECIALLY NEAR CSV...BUT POTENTIAL APPEARS TOO REMOTE TO MENTION
IN TAF ATTM.

PREV DISCUSSION... /ISSUED 205 AM CDT MON MAY 20 2013/

DISCUSSION...HIGH PRESSURE REMAINS SITUATED OFF TO THE EAST, WITH
SURFACE PRESSURE GRADIENT STARTING TO INCREASE ACROSS MIDDLE
TENNESSEE. MOSTLY CLEAR SKIES HAVE SETTLED IN ACROSS THE MID
STATE, WITH FOG EXPECTED TO DEVELOP TOWARD MORNING, ESPECIALLY IN
AREAS THAT RECEIVED RAINFALL ON SUNDAY. HAD ORIGINALLY GONE WITH A
DRY FORECAST TODAY, BUT THE NAM SOUNDING FOR BNA THIS AFTERNOON
SHOWS DEEP LEFTOVER INSTABILITY, WITH A CAPE EXCEEDING 3000 J/KG
DURING PEAK HEATING AND A LIFTED INDEX OF -7. THESE FIGURES APPEAR
TO BE REPRESENTATIVE ACROSS THE ENTIRE MID STATE. THE SOUNDING IS
A BIT DRY, WITH ONLY A SHALLOW MOIST LAYER IN THE LOW LEVELS, BUT
GIVEN THAT SEVERAL PLACES WILL HIT 90 DEGREES TODAY, CANNOT RULE
OUT ISOLATED CELLS POPPING UP DURING THE AFTERNOON. THE SPC`S
LATEST DAY 2 OUTLOOK PLACES ABOUT THE WESTERN 1/3 OF MIDDLE
TENNESSEE UNDER A SLIGHT RISK OF SEVERE STORMS TUESDAY AND TUESDAY
NIGHT. ACTIVITY WILL FURTHER INCREASE ON WEDNESDAY AS THE ACTUAL
COLD FRONT ARRIVES.

&&

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

$$

07

000
FXUS64 KMRX 201730
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
130 PM EDT MON MAY 20 2013

.AVIATION...WARM AND MOIST AIR WILL REMAIN IN PLACE THROUGH THE TAF
PERIOD.  STRONG DAYTIME HEATING WILL HELP DESTABILIZE THE ATMOSPHERE
AND EXPECTED TO SEE DIURNAL CONVECTION DEVELOP DURING THE
AFTERNOON.  THE BULK OF THIS ACTIVITY SHOULD STAY OVER HIGHER
TERRAIN AND NOT EXPECTED TO EFFECT AREA TAFS.  OVERNIGHT...FOG IS
EXPECTED TO DEVELOP ONCE AGAIN FOR MVFR AND POSSIBLY IFR CONDITIONS
BY SUNRISE.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

000
FXUS64 KMEG 201720
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1220 PM CDT MON MAY 20 2013

.UPDATE...AVIATION DISCUSSION.

&&

.PREV DISCUSSION... /ISSUED 1002 AM CDT MON MAY 20 2013/

UPDATE...

FORECAST IN GOOD SHAPE...WITH ONLY A MINOR TWEAK TO REMOVE THE
SHOWERS AND THUNDERSTORMS JUST A BIT EARLIER THAN PREVIOUS
THINKING ACROSS PORTIONS OF NE AR DUE TO CAPPING. WINDS ARE
STARTING TO BUILD FROM WEST TO EAST ACROSS THE REGION WITH GUSTS
CLOSE TO THE 20KT RANGE ALONG AND WEST OF THE RIVER. HIGHS SHOULD
STILL PUSH UPPER 80S OR CLOSE TO 90 ACROSS ENTIRE AREA. --ABS

.PREV DISCUSSION... /ISSUED 453 AM CDT MON MAY 20 2013/

DISCUSSION...

A POTENT UPPER LEVEL LOW PRESSURE SYSTEM REMAINS NEARLY STATIONARY
OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WITH A DOWNSTREAM
UPPER LEVEL RIDGE OF HIGH PRESSURE EXTENDING FROM THE DEEP SOUTH
ACROSS THE MID SOUTH INTO THE OHIO VALLEY. A LEAD SHORTWAVE
ROTATING THROUGH MISSOURI EARLY THIS MORNING CONTINUES TO LIFT
NORTHEAST WITH THUNDERSTORMS OVER MISSOURI CURRENTLY IN A
WEAKENING PHASE AS THE UPPER SUPPORT LIFTS NORTHEAST OF THE
REGION. THIS CONVECTIVE ACTIVITY WILL LIKELY LEAVE A CONVECTIVE
OUTFLOW BOUNDARY THAT WILL EXTEND ACROSS SOUTH CENTRAL MISSOURI
WESTWARD INTO NORTHEAST OKLAHOMA.

ACROSS THE MID SOUTH...THE UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
KEEP DRY AND VERY WARM WEATHER IN PLACE TODAY. HUMID CONDITIONS
WILL ALSO PERSIST AS DEWPOINTS REMAIN IN THE UPPER 60S THROUGH THE
DAY. HIGH TEMPERATURES SHOULD TOP OUT AROUND 90 DEGREES IN MOST
AREAS. SOME LOW LEVEL STRATUS WILL OVERSPREAD THE REGION EARLY
THIS MORNING FROM THE SOUTH...BUT SHOULD MIX OUT FAIRLY QUICKLY
WITH MOSTLY SUNNY SKIES DEVELOPING BY LATE MORNING.

THE AFOREMENTIONED CONVECTIVE OUTFLOW BOUNDARY TO THE NORTH OF THE
FORECAST AREA WILL LIKELY BECOME A FOCUS FOR RENEWED THUNDERSTORM
DEVELOPMENT LATE THIS AFTERNOON INTO THIS EVENING AS ANOTHER MID
LEVEL SHORTWAVE EJECTS FROM THE SOUTHERN PLAINS INTO THE MID
MISSISSIPPI VALLEY TONIGHT. NUMEROUS THUNDERSTORMS SHOULD DEVELOP
ACROSS THE OZARKS OF SOUTHERN MISSOURI SOUTHWESTWARD INTO CENTRAL
OKLAHOMA BY THIS EVENING. INITIAL THUNDERSTORM MODE SHOULD BEGIN
AS SUPERCELLS BUT GRADUALLY TRANSITION INTO A QUASI-LINEAR
CONVECTIVE SYSTEM (QLCS) AS IT ADVANCES EAST-NORTHEASTWARD
OVERNIGHT. THIS LINE OF STORMS MAY ADVANCE ACROSS PORTIONS OF
NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL AFTER MIDNIGHT. THE
AIRMASS AHEAD OF THIS CONVECTIVE COMPLEX SHOULD REMAIN
SUFFICIENTLY UNSTABLE WITH MLCAPES BETWEEN 1500-2500 J/KG...LI/S
AROUND -6C...AND MID LEVEL LAPSE RATES IN EXCESS OF 7.5 C/KM. IN
ADDITION...DEEP LAYER SHEAR BETWEEN 40-50 KTS WILL SPREAD ACROSS
NORTHWEST PORTIONS OF THE FORECAST AREA OVERNIGHT. THIS
COMBINATION OF SHEAR AND INSTABILITY MAY SUPPORT A CONTINUED
SEVERE THREAT AFTER MIDNIGHT INTO PORTIONS OF NORTHEAST ARKANSAS
AND THE MISSOURI BOOTHEEL. THE PRIMARY THREATS APPEAR TO BE
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO CANNOT BE RULED
OUT BUT SHOULD NOT BE THE PRIMARY SEVERE WEATHER HAZARD AS LOW
LEVEL WINDS VEER LATE TONIGHT. STORMS SHOULD EVENTUALLY WEAKEN
TOWARDS SUNRISE AS THEY APPROACH THE MISSISSIPPI RIVER AND
NORTHWEST TENNESSEE AS THE UPPER SUPPORT LIFTS TO THE NORTHEAST OF
THE CONVECTIVE ACTIVITY. THIS ACTIVITY SHOULD EVENTUALLY FIZZLE
LATER TUESDAY MORNING OVER NORTHWEST PORTIONS OF THE MID SOUTH.

THE UPPER RIDGE SHOULD TEMPORARILY REBUILD OVER THE MID SOUTH
DURING THE DAY TUESDAY BRINGING A LULL IN ANY CONVECTIVE ACTIVITY
AS THE CAPPING INVERSION STRENGTHENS AND INHIBITS CONVECTIVE
DEVELOPMENT. SKIES SHOULD SCATTER OUT WITH TEMPERATURES RISING
WELL INTO THE 80S BY TUESDAY AFTERNOON ALONG WITH CONTINUED HUMID
CONDITIONS AS DEWPOINTS REMAIN NEAR 70 DEGREES. A THIRD AND
STRONGER SHORTWAVE WILL EJECT FROM THE SOUTHERN PLAINS INTO THE
MID SOUTH BY TUESDAY EVENING. THIS SHORTWAVE SHOULD TAKE ON A
NEGATIVE TILT AS IT PROGRESSES ACROSS THE MID SOUTH TUESDAY NIGHT
INTO WEDNESDAY MORNING. AS THIS OCCURS...THE CAPPING INVERSION
WILL BEGIN TO ERODE ALLOWING FOR NUMEROUS THUNDERSTORMS TO DEVELOP
OVER WESTERN SECTIONS OF THE MID SOUTH LATE TUESDAY AFTERNOON.
THUNDERSTORMS SHOULD QUICKLY SPREAD NORTHEAST ACROSS THE REGION
TUESDAY NIGHT INTO WEDNESDAY MORNING. THE ATMOSPHERE SHOULD REMAIN
MODERATELY UNSTABLE THROUGH TUESDAY NIGHT WITH SBCAPE VALUES
RANGING FROM 1500-2500 J/KG...LI/S -6C TO -10C...AND MID LEVEL
LAPSE RATES GREATER THAN 7.0 C/KM. IN ADDITION...DEEP LAYER SHEAR
SHOULD STRENGTHEN AHEAD OF THE SHORTWAVE AS A 40-50 KT LOW LEVEL
JET OVERSPREADS THE AREA ALONG WITH AROUND 50 KTS OF MID LEVEL
FLOW. INITIAL THUNDERSTORM MODE SHOULD BE A MIX OF SUPERCELLS AND
BOWING LINE SEGMENTS EARLY IN THE CONVECTIVE EVOLUTION THROUGH
TUESDAY EVENING...EVENTUALLY TRANSITIONING TO AN EXPANSIVE QUASI-
LINEAR CONVECTIVE SYSTEM (QLCS). THE PRIMARY SEVERE THREATS WILL
BE DAMAGING WINDS AND LARGE HAIL. A TORNADO THREAT WILL EXIST
EARLY IN THE EVENT MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER
TUESDAY EVENING...ESPECIALLY WITH ANY DISCRETE SUPERCELLS THAT
DEVELOP. ANY TORNADO THREAT SHOULD DIMINISH LATER TUESDAY NIGHT AS
LOW LEVEL FLOW VEERS.

THE LINE OF THUNDERSTORMS SHOULD CONTINUE TO ADVANCE EAST OF THE
MISSISSIPPI RIVER LATER TUESDAY NIGHT INTO WEDNESDAY MORNING. THE
SEVERE WEATHER THREAT SHOULD GRADUALLY DIMINISH LATE TUESDAY NIGHT
INTO WEDNESDAY MORNING AS THE SHORTWAVE LIFTS NORTHEAST OF THE
REGION AND DEEP LAYER SHEAR WEAKENS. CHANCES FOR SHOWERS AND
THUNDERSTORMS SHOULD DIMINISH FROM WEST TO EAST DURING THE DAY ON
WEDNESDAY.

AS THE EARLY WEEK UPPER LEVEL LOW OVER THE CENTRAL HIGH PLAINS
MOVES EAST INTO THE GREAT LAKES BY THE END OF THE WEEK...ANOTHER
SHORTWAVE WILL EJECT SOUTHEAST FROM THE MIDDLE MISSISSIPPI VALLEY
THROUGH THE TENNESSEE VALLEY ON THURSDAY. THIS WILL HELP TO PUSH A
COLD FRONT ACROSS THE FORECAST AREA BY THURSDAY AFTERNOON.
ADDITIONAL SHOWERS AND THUNDERSTORMS MAY DEVELOP AHEAD OF THE
SOUTHWARD ADVANCING COLD FRONT. A FEW STORMS MAY BECOME STRONG AS
DEEP LAYER SHEAR RESTRENGTHENS ACROSS THE AREA. THE FRONT SHOULD PUSH
SOUTH OF THE REGION THURSDAY NIGHT WITH HIGH PRESSURE BUILDING IN.

HIGH PRESSURE SHOULD CONTROL THE MID SOUTH WEATHER FOR FRIDAY INTO
NEXT WEEKEND WITH A RETURN TO DRY AND LESS HUMID WEATHER.
TEMPERATURES WILL DROP BACK TO NEAR SEASONAL LEVELS FOR THE END OF
THE WEEK INTO NEXT WEEKEND.

JLH

.AVIATION...
18Z TAF CYCLE

MID LEVEL CLOUDS WILL REMAIN ACROSS THE MIDSOUTH TODAY...GENERALLY
3000-4000 FT. WE WILL LIKELY SEE CIGS BECOME SCT AFTER
SUNSET...BUT ADDITIONAL LOW TO MID LEVEL CLOUDS WILL RETURN TOWARD
MORNING. SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE
TOMORROW...BUT NOT LIKELY MAKE IT TO MEM...MKL...OR TUP BEFORE
18Z. WILL CARRY VCTS AT JBR AFTER 11Z. MVFR CIGS ARE EXPECTED AT
ALL SITES TOMORROW. WINDS WILL REMAIN SOUTHERLY...GENERALLY AROUND
10 KNOTS WITH GUSTS IN EXCESS OF 20 KTS...STRONGEST AT JBR.


&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  89  74  88  69 /  10  10  30  70
MKL  88  72  88  69 /  10  10  30  70
JBR  89  69  86  66 /  20  40  60  90
TUP  89  71  89  70 /   0  10  20  40

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMEG 201502
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1002 AM CDT MON MAY 20 2013

.UPDATE...

FORECAST IN GOOD SHAPE...WITH ONLY A MINOR TWEAK TO REMOVE THE
SHOWERS AND THUNDERSTORMS JUST A BIT EARLIER THAN PREVIOUS
THINKING ACROSS PORTIONS OF NE AR DUE TO CAPPING. WINDS ARE
STARTING TO BUILD FROM WEST TO EAST ACROSS THE REGION WITH GUSTS
CLOSE TO THE 20KT RANGE ALONG AND WEST OF THE RIVER. HIGHS SHOULD
STILL PUSH UPPER 80S OR CLOSE TO 90 ACROSS ENTIRE AREA. --ABS

&&

.PREV DISCUSSION... /ISSUED 620 AM CDT MON MAY 20 2013/

UPDATE...
UPDATED TO ADD 12Z AVIATION DISCUSSION.

PREV DISCUSSION... /ISSUED 453 AM CDT MON MAY 20 2013/

DISCUSSION...

A POTENT UPPER LEVEL LOW PRESSURE SYSTEM REMAINS NEARLY STATIONARY
OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WITH A DOWNSTREAM
UPPER LEVEL RIDGE OF HIGH PRESSURE EXTENDING FROM THE DEEP SOUTH
ACROSS THE MID SOUTH INTO THE OHIO VALLEY. A LEAD SHORTWAVE
ROTATING THROUGH MISSOURI EARLY THIS MORNING CONTINUES TO LIFT
NORTHEAST WITH THUNDERSTORMS OVER MISSOURI CURRENTLY IN A
WEAKENING PHASE AS THE UPPER SUPPORT LIFTS NORTHEAST OF THE
REGION. THIS CONVECTIVE ACTIVITY WILL LIKELY LEAVE A CONVECTIVE
OUTFLOW BOUNDARY THAT WILL EXTEND ACROSS SOUTH CENTRAL MISSOURI
WESTWARD INTO NORTHEAST OKLAHOMA.

ACROSS THE MID SOUTH...THE UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
KEEP DRY AND VERY WARM WEATHER IN PLACE TODAY. HUMID CONDITIONS
WILL ALSO PERSIST AS DEWPOINTS REMAIN IN THE UPPER 60S THROUGH THE
DAY. HIGH TEMPERATURES SHOULD TOP OUT AROUND 90 DEGREES IN MOST
AREAS. SOME LOW LEVEL STRATUS WILL OVERSPREAD THE REGION EARLY
THIS MORNING FROM THE SOUTH...BUT SHOULD MIX OUT FAIRLY QUICKLY
WITH MOSTLY SUNNY SKIES DEVELOPING BY LATE MORNING.

THE AFOREMENTIONED CONVECTIVE OUTFLOW BOUNDARY TO THE NORTH OF THE
FORECAST AREA WILL LIKELY BECOME A FOCUS FOR RENEWED THUNDERSTORM
DEVELOPMENT LATE THIS AFTERNOON INTO THIS EVENING AS ANOTHER MID
LEVEL SHORTWAVE EJECTS FROM THE SOUTHERN PLAINS INTO THE MID
MISSISSIPPI VALLEY TONIGHT. NUMEROUS THUNDERSTORMS SHOULD DEVELOP
ACROSS THE OZARKS OF SOUTHERN MISSOURI SOUTHWESTWARD INTO CENTRAL
OKLAHOMA BY THIS EVENING. INITIAL THUNDERSTORM MODE SHOULD BEGIN
AS SUPERCELLS BUT GRADUALLY TRANSITION INTO A QUASI-LINEAR
CONVECTIVE SYSTEM (QLCS) AS IT ADVANCES EAST-NORTHEASTWARD
OVERNIGHT. THIS LINE OF STORMS MAY ADVANCE ACROSS PORTIONS OF
NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL AFTER MIDNIGHT. THE
AIRMASS AHEAD OF THIS CONVECTIVE COMPLEX SHOULD REMAIN
SUFFICIENTLY UNSTABLE WITH MLCAPES BETWEEN 1500-2500 J/KG...LI/S
AROUND -6C...AND MID LEVEL LAPSE RATES IN EXCESS OF 7.5 C/KM. IN
ADDITION...DEEP LAYER SHEAR BETWEEN 40-50 KTS WILL SPREAD ACROSS
NORTHWEST PORTIONS OF THE FORECAST AREA OVERNIGHT. THIS
COMBINATION OF SHEAR AND INSTABILITY MAY SUPPORT A CONTINUED
SEVERE THREAT AFTER MIDNIGHT INTO PORTIONS OF NORTHEAST ARKANSAS
AND THE MISSOURI BOOTHEEL. THE PRIMARY THREATS APPEAR TO BE
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO CANNOT BE RULED
OUT BUT SHOULD NOT BE THE PRIMARY SEVERE WEATHER HAZARD AS LOW
LEVEL WINDS VEER LATE TONIGHT. STORMS SHOULD EVENTUALLY WEAKEN
TOWARDS SUNRISE AS THEY APPROACH THE MISSISSIPPI RIVER AND
NORTHWEST TENNESSEE AS THE UPPER SUPPORT LIFTS TO THE NORTHEAST OF
THE CONVECTIVE ACTIVITY. THIS ACTIVITY SHOULD EVENTUALLY FIZZLE
LATER TUESDAY MORNING OVER NORTHWEST PORTIONS OF THE MID SOUTH.

THE UPPER RIDGE SHOULD TEMPORARILY REBUILD OVER THE MID SOUTH
DURING THE DAY TUESDAY BRINGING A LULL IN ANY CONVECTIVE ACTIVITY
AS THE CAPPING INVERSION STRENGTHENS AND INHIBITS CONVECTIVE
DEVELOPMENT. SKIES SHOULD SCATTER OUT WITH TEMPERATURES RISING
WELL INTO THE 80S BY TUESDAY AFTERNOON ALONG WITH CONTINUED HUMID
CONDITIONS AS DEWPOINTS REMAIN NEAR 70 DEGREES. A THIRD AND
STRONGER SHORTWAVE WILL EJECT FROM THE SOUTHERN PLAINS INTO THE
MID SOUTH BY TUESDAY EVENING. THIS SHORTWAVE SHOULD TAKE ON A
NEGATIVE TILT AS IT PROGRESSES ACROSS THE MID SOUTH TUESDAY NIGHT
INTO WEDNESDAY MORNING. AS THIS OCCURS...THE CAPPING INVERSION
WILL BEGIN TO ERODE ALLOWING FOR NUMEROUS THUNDERSTORMS TO DEVELOP
OVER WESTERN SECTIONS OF THE MID SOUTH LATE TUESDAY AFTERNOON.
THUNDERSTORMS SHOULD QUICKLY SPREAD NORTHEAST ACROSS THE REGION
TUESDAY NIGHT INTO WEDNESDAY MORNING. THE ATMOSPHERE SHOULD REMAIN
MODERATELY UNSTABLE THROUGH TUESDAY NIGHT WITH SBCAPE VALUES
RANGING FROM 1500-2500 J/KG...LI/S -6C TO -10C...AND MID LEVEL
LAPSE RATES GREATER THAN 7.0 C/KM. IN ADDITION...DEEP LAYER SHEAR
SHOULD STRENGTHEN AHEAD OF THE SHORTWAVE AS A 40-50 KT LOW LEVEL
JET OVERSPREADS THE AREA ALONG WITH AROUND 50 KTS OF MID LEVEL
FLOW. INITIAL THUNDERSTORM MODE SHOULD BE A MIX OF SUPERCELLS AND
BOWING LINE SEGMENTS EARLY IN THE CONVECTIVE EVOLUTION THROUGH
TUESDAY EVENING...EVENTUALLY TRANSITIONING TO AN EXPANSIVE QUASI-
LINEAR CONVECTIVE SYSTEM (QLCS). THE PRIMARY SEVERE THREATS WILL
BE DAMAGING WINDS AND LARGE HAIL. A TORNADO THREAT WILL EXIST
EARLY IN THE EVENT MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER
TUESDAY EVENING...ESPECIALLY WITH ANY DISCRETE SUPERCELLS THAT
DEVELOP. ANY TORNADO THREAT SHOULD DIMINISH LATER TUESDAY NIGHT AS
LOW LEVEL FLOW VEERS.

THE LINE OF THUNDERSTORMS SHOULD CONTINUE TO ADVANCE EAST OF THE
MISSISSIPPI RIVER LATER TUESDAY NIGHT INTO WEDNESDAY MORNING. THE
SEVERE WEATHER THREAT SHOULD GRADUALLY DIMINISH LATE TUESDAY NIGHT
INTO WEDNESDAY MORNING AS THE SHORTWAVE LIFTS NORTHEAST OF THE
REGION AND DEEP LAYER SHEAR WEAKENS. CHANCES FOR SHOWERS AND
THUNDERSTORMS SHOULD DIMINISH FROM WEST TO EAST DURING THE DAY ON
WEDNESDAY.

AS THE EARLY WEEK UPPER LEVEL LOW OVER THE CENTRAL HIGH PLAINS
MOVES EAST INTO THE GREAT LAKES BY THE END OF THE WEEK...ANOTHER
SHORTWAVE WILL EJECT SOUTHEAST FROM THE MIDDLE MISSISSIPPI VALLEY
THROUGH THE TENNESSEE VALLEY ON THURSDAY. THIS WILL HELP TO PUSH A
COLD FRONT ACROSS THE FORECAST AREA BY THURSDAY AFTERNOON.
ADDITIONAL SHOWERS AND THUNDERSTORMS MAY DEVELOP AHEAD OF THE
SOUTHWARD ADVANCING COLD FRONT. A FEW STORMS MAY BECOME STRONG AS
DEEP LAYER SHEAR RESTRENGTHENS ACROSS THE AREA. THE FRONT SHOULD PUSH
SOUTH OF THE REGION THURSDAY NIGHT WITH HIGH PRESSURE BUILDING IN.

HIGH PRESSURE SHOULD CONTROL THE MID SOUTH WEATHER FOR FRIDAY INTO
NEXT WEEKEND WITH A RETURN TO DRY AND LESS HUMID WEATHER.
TEMPERATURES WILL DROP BACK TO NEAR SEASONAL LEVELS FOR THE END OF
THE WEEK INTO NEXT WEEKEND.

JLH

AVIATION...
12Z TAF CYCLE

LOW STRATUS HAS ALREADY DEVELOPED ACROSS THE LOWER MISSISSIPPI
VALLEY EARLY THIS MORNING AND WILL SPREAD INTO ALL TAF SITES
BETWEEN 20/12-16Z. OTHERWISE...VFR CONDITIONS EXPECTED TO PREVAIL
THROUGH MUCH OF THE PERIOD AS CLOUDS MIX OUT BY LATE THIS MORNING
MORNING. SOUTH WINDS WILL INCREASE TO 10-16 KTS SUSTAINED WITH
GUSTS BETWEEN 18-26 KTS...ESPECIALLY AT JBR AND MEM. VCTS POSSIBLE AT
JBR MAINLY AFTER 21/08Z AS A SHORTWAVE TROUGH MOVES ACROSS
PORTIONS OF THE MIDDLE AND LOWER MISSISSIPPI VALLEYS.

CJC

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  89  74  88  69 /  10  10  30  70
MKL  88  72  88  69 /  10  10  30  70
JBR  89  69  86  66 /  20  40  60  90
TUP  89  71  89  70 /   0  10  20  40

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KOHX 201442
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
942 AM CDT MON MAY 20 2013

.UPDATE...
DEWPOINTS ON THE INCREASE OVER THE LAST FEW HOURS. SHOULD SEE THE
TREND WHEREBY AN INCREASE IN CAPES AND DEWPOINTS CONTINUE INTO THE
AFTERNOON. NO REAL DYNAMICS TO SPEAK OF THOUGH AS THE BEST
ORGANIZED CONVECTION REMAINS OUT WEST ALONG THE CENTRAL PLAINS.
THAT ASSOCIATED FRONTAL BOUNDARY WILL REMAIN TO OUR WEST THROUGH
AT LEAST TODAY AND TONIGHT.

FOR THE UPDATE...WILL INCREASE SKY COVER IN GRIDS AS WELL AS LOWER
TEMPS A DEGREE OR TWO. LATEST MAV GUIDANCE HAS BACKED OFF A FEW
DEGREES AS MORE IN THE WAY OF CLOUD COVER IS EXPECTED.

OTW...NO OTHER CHANGES...ISOLATED AFT SHOWERS AND TSTMS ARE IN THE
GRIDS AND THAT LOOKS SUFFICIENT.

&&

.PREV DISCUSSION... /ISSUED 626 AM CDT MON MAY 20 2013/

UPDATE...

12Z TAF DISCUSSION.

AVIATION...

IR SATELLITE IMAGERY SHOWS LOW CLOUDS HAVE VERY RAPIDLY ADVECTED
NORTHWARD INTO THE CENTRAL MID STATE PAST HOUR WITH MVFR CIGS NOW
AT BNA. COULD ALSO SEE MVFR CIGS AT CKV BRIEFLY THIS MORNING...BUT
BOTH BNA/CKV EXPECTED TO BECOME VFR BY LATE MORNING. PATCHY FOG
HAS RESULTED IN OCCASIONAL VIS RESTRICTIONS OVERNIGHT...BUT
EXPECTED TO IMPROVE TO VFR VIS AREAWIDE BY 14Z. OTHERWISE...EXPECT
SCATTERED CU THIS AFTERNOON WITH SOUTH TO SOUTHWEST WINDS 5 TO 11
KTS. AN ISOLATED -SHRA/-TSRA IS POSSIBLE THIS AFTERNOON
ESPECIALLY NEAR CSV...BUT POTENTIAL APPEARS TOO REMOTE TO MENTION
IN TAF ATTM.

PREV DISCUSSION... /ISSUED 205 AM CDT MON MAY 20 2013/

DISCUSSION...HIGH PRESSURE REMAINS SITUATED OFF TO THE EAST, WITH
SURFACE PRESSURE GRADIENT STARTING TO INCREASE ACROSS MIDDLE
TENNESSEE. MOSTLY CLEAR SKIES HAVE SETTLED IN ACROSS THE MID
STATE, WITH FOG EXPECTED TO DEVELOP TOWARD MORNING, ESPECIALLY IN
AREAS THAT RECEIVED RAINFALL ON SUNDAY. HAD ORIGINALLY GONE WITH A
DRY FORECAST TODAY, BUT THE NAM SOUNDING FOR BNA THIS AFTERNOON
SHOWS DEEP LEFTOVER INSTABILITY, WITH A CAPE EXCEEDING 3000 J/KG
DURING PEAK HEATING AND A LIFTED INDEX OF -7. THESE FIGURES APPEAR
TO BE REPRESENTATIVE ACROSS THE ENTIRE MID STATE. THE SOUNDING IS
A BIT DRY, WITH ONLY A SHALLOW MOIST LAYER IN THE LOW LEVELS, BUT
GIVEN THAT SEVERAL PLACES WILL HIT 90 DEGREES TODAY, CANNOT RULE
OUT ISOLATED CELLS POPPING UP DURING THE AFTERNOON. THE SPC`S
LATEST DAY 2 OUTLOOK PLACES ABOUT THE WESTERN 1/3 OF MIDDLE
TENNESSEE UNDER A SLIGHT RISK OF SEVERE STORMS TUESDAY AND TUESDAY
NIGHT. ACTIVITY WILL FURTHER INCREASE ON WEDNESDAY AS THE ACTUAL
COLD FRONT ARRIVES.

&&

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

$$

21

000
FXUS64 KMRX 201432
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1030 AM EDT MON MAY 20 2013

.DISCUSSION...FOG HAS LIFT ACROSS MUCH OF THE AREA AND THE DENSE FOG
ADVISORY HAS BEEN ALLOWED TO EXPIRE.  OTHERWISE...WARM ...MOIST AIR
IN PLACE AND STRONG DAYTIME HEATING THIS AFTERNOON WILL HELP
DESTABILIZE THE ATMOSPHERE.  THE RESULT WILL BE DIURNAL CONVECTION
CENTERED OVER HIGHER TERRAIN.  A STRAY STORM MAY BECOME STRONG...
POSSIBLY SEVERE...ADDITIONALLY...LOCALIZED HEAVY RAINFALL IS
POSSIBLE WITH ANY OF THE STORMS.  ALL ON TRACK IN THE CURRENT
FORECAST...WILL UPDATE TO REMOVE FOG ADVISORY.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN  87  66  90  67  85 /  10  10  20  20  60
KNOXVILLE AIRPORT, TN    85  65  88  66  83 /  20  10  20  20  60
OAK RIDGE, TN            86  65  87  66  83 /  20  20  20  20  60
TRI CITIES AIRPORT, TN   82  57  85  60  82 /  40  20  30  20  50

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

MJB

000
FXUS64 KOHX 201126
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
626 AM CDT MON MAY 20 2013

.UPDATE...

12Z TAF DISCUSSION.

&&

.AVIATION...

IR SATELLITE IMAGERY SHOWS LOW CLOUDS HAVE VERY RAPIDLY ADVECTED
NORTHWARD INTO THE CENTRAL MID STATE PAST HOUR WITH MVFR CIGS NOW
AT BNA. COULD ALSO SEE MVFR CIGS AT CKV BRIEFLY THIS MORNING...BUT
BOTH BNA/CKV EXPECTED TO BECOME VFR BY LATE MORNING. PATCHY FOG
HAS RESULTED IN OCCASIONAL VIS RESTRICTIONS OVERNIGHT...BUT
EXPECTED TO IMPROVE TO VFR VIS AREAWIDE BY 14Z. OTHERWISE...EXPECT
SCATTERED CU THIS AFTERNOON WITH SOUTH TO SOUTHWEST WINDS 5 TO 11
KTS. AN ISOLATED -SHRA/-TSRA IS POSSIBLE THIS AFTERNOON
ESPECIALLY NEAR CSV...BUT POTENTIAL APPEARS TOO REMOTE TO MENTION
IN TAF ATTM.

&&

.PREV DISCUSSION... /ISSUED 205 AM CDT MON MAY 20 2013/

DISCUSSION...HIGH PRESSURE REMAINS SITUATED OFF TO THE EAST, WITH
SURFACE PRESSURE GRADIENT STARTING TO INCREASE ACROSS MIDDLE
TENNESSEE. MOSTLY CLEAR SKIES HAVE SETTLED IN ACROSS THE MID
STATE, WITH FOG EXPECTED TO DEVELOP TOWARD MORNING, ESPECIALLY IN
AREAS THAT RECEIVED RAINFALL ON SUNDAY. HAD ORIGINALLY GONE WITH A
DRY FORECAST TODAY, BUT THE NAM SOUNDING FOR BNA THIS AFTERNOON
SHOWS DEEP LEFTOVER INSTABILITY, WITH A CAPE EXCEEDING 3000 J/KG
DURING PEAK HEATING AND A LIFTED INDEX OF -7. THESE FIGURES APPEAR
TO BE REPRESENTATIVE ACROSS THE ENTIRE MID STATE. THE SOUNDING IS
A BIT DRY, WITH ONLY A SHALLOW MOIST LAYER IN THE LOW LEVELS, BUT
GIVEN THAT SEVERAL PLACES WILL HIT 90 DEGREES TODAY, CANNOT RULE
OUT ISOLATED CELLS POPPING UP DURING THE AFTERNOON. THE SPC`S
LATEST DAY 2 OUTLOOK PLACES ABOUT THE WESTERN 1/3 OF MIDDLE
TENNESSEE UNDER A SLIGHT RISK OF SEVERE STORMS TUESDAY AND TUESDAY
NIGHT. ACTIVITY WILL FURTHER INCREASE ON WEDNESDAY AS THE ACTUAL
COLD FRONT ARRIVES.

&&

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

$$

55

000
FXUS64 KMRX 201124
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
724 AM EDT MON MAY 20 2013

.AVIATION...MAIN CONCERN THROUGH 14Z IS THE VLIFR-LIFR CONDITIONS AT
TYS AND CHA DUE TO RADIATIONAL FOG DEVELOPMENT. AT TRI...LIFR CONDITIONS
DUE TO CEILINGS WILL CONTINUE THROUGH 14Z AS WELL.

FOG/LOW-CLOUDS WILL DISSIPATE/LIFT THIS MORNING WITH VFR CONDITIONS
RETURNING BY 16 UTC AT ALL TAF SITES. UPPER LOW THAT MOVED ACROSS
THE TENNESSEE VALLEY TODAY HAS MOVED EAST OF THE AREA WITH RIDING
ALOFT BUILDING OVER THE REGION TODAY AND TONIGHT. ISOLATED
STRONG-SEVERE STORMS ANTICIPATED OVER THE HIGHER TERRAIN THIS
AFTERNOON MOVING INTO THE VALLEY DURING THE EVENING.

FOR TONIGHT...CLEAR SKY AND CONTINUE MOIST GROUND WILL PRODUCE AREAS
OF FOG/LOW-CLOUDS. VLIFR/LIFR CONDITIONS ARE POSSIBLE AT TRI AND TYS AGAIN
EARLY TUESDAY MORNING.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

&&

$$

000
FXUS64 KMEG 201120
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
620 AM CDT MON MAY 20 2013

.UPDATE...
UPDATED TO ADD 12Z AVIATION DISCUSSION.

&&

.PREV DISCUSSION... /ISSUED 453 AM CDT MON MAY 20 2013/

DISCUSSION...

A POTENT UPPER LEVEL LOW PRESSURE SYSTEM REMAINS NEARLY STATIONARY
OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WITH A DOWNSTREAM
UPPER LEVEL RIDGE OF HIGH PRESSURE EXTENDING FROM THE DEEP SOUTH
ACROSS THE MID SOUTH INTO THE OHIO VALLEY. A LEAD SHORTWAVE
ROTATING THROUGH MISSOURI EARLY THIS MORNING CONTINUES TO LIFT
NORTHEAST WITH THUNDERSTORMS OVER MISSOURI CURRENTLY IN A
WEAKENING PHASE AS THE UPPER SUPPORT LIFTS NORTHEAST OF THE
REGION. THIS CONVECTIVE ACTIVITY WILL LIKELY LEAVE A CONVECTIVE
OUTFLOW BOUNDARY THAT WILL EXTEND ACROSS SOUTH CENTRAL MISSOURI
WESTWARD INTO NORTHEAST OKLAHOMA.

ACROSS THE MID SOUTH...THE UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
KEEP DRY AND VERY WARM WEATHER IN PLACE TODAY. HUMID CONDITIONS
WILL ALSO PERSIST AS DEWPOINTS REMAIN IN THE UPPER 60S THROUGH THE
DAY. HIGH TEMPERATURES SHOULD TOP OUT AROUND 90 DEGREES IN MOST
AREAS. SOME LOW LEVEL STRATUS WILL OVERSPREAD THE REGION EARLY
THIS MORNING FROM THE SOUTH...BUT SHOULD MIX OUT FAIRLY QUICKLY
WITH MOSTLY SUNNY SKIES DEVELOPING BY LATE MORNING.

THE AFOREMENTIONED CONVECTIVE OUTFLOW BOUNDARY TO THE NORTH OF THE
FORECAST AREA WILL LIKELY BECOME A FOCUS FOR RENEWED THUNDERSTORM
DEVELOPMENT LATE THIS AFTERNOON INTO THIS EVENING AS ANOTHER MID
LEVEL SHORTWAVE EJECTS FROM THE SOUTHERN PLAINS INTO THE MID
MISSISSIPPI VALLEY TONIGHT. NUMEROUS THUNDERSTORMS SHOULD DEVELOP
ACROSS THE OZARKS OF SOUTHERN MISSOURI SOUTHWESTWARD INTO CENTRAL
OKLAHOMA BY THIS EVENING. INITIAL THUNDERSTORM MODE SHOULD BEGIN
AS SUPERCELLS BUT GRADUALLY TRANSITION INTO A QUASI-LINEAR
CONVECTIVE SYSTEM (QLCS) AS IT ADVANCES EAST-NORTHEASTWARD
OVERNIGHT. THIS LINE OF STORMS MAY ADVANCE ACROSS PORTIONS OF
NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL AFTER MIDNIGHT. THE
AIRMASS AHEAD OF THIS CONVECTIVE COMPLEX SHOULD REMAIN
SUFFICIENTLY UNSTABLE WITH MLCAPES BETWEEN 1500-2500 J/KG...LI/S
AROUND -6C...AND MID LEVEL LAPSE RATES IN EXCESS OF 7.5 C/KM. IN
ADDITION...DEEP LAYER SHEAR BETWEEN 40-50 KTS WILL SPREAD ACROSS
NORTHWEST PORTIONS OF THE FORECAST AREA OVERNIGHT. THIS
COMBINATION OF SHEAR AND INSTABILITY MAY SUPPORT A CONTINUED
SEVERE THREAT AFTER MIDNIGHT INTO PORTIONS OF NORTHEAST ARKANSAS
AND THE MISSOURI BOOTHEEL. THE PRIMARY THREATS APPEAR TO BE
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO CANNOT BE RULED
OUT BUT SHOULD NOT BE THE PRIMARY SEVERE WEATHER HAZARD AS LOW
LEVEL WINDS VEER LATE TONIGHT. STORMS SHOULD EVENTUALLY WEAKEN
TOWARDS SUNRISE AS THEY APPROACH THE MISSISSIPPI RIVER AND
NORTHWEST TENNESSEE AS THE UPPER SUPPORT LIFTS TO THE NORTHEAST OF
THE CONVECTIVE ACTIVITY. THIS ACTIVITY SHOULD EVENTUALLY FIZZLE
LATER TUESDAY MORNING OVER NORTHWEST PORTIONS OF THE MID SOUTH.

THE UPPER RIDGE SHOULD TEMPORARILY REBUILD OVER THE MID SOUTH
DURING THE DAY TUESDAY BRINGING A LULL IN ANY CONVECTIVE ACTIVITY
AS THE CAPPING INVERSION STRENGTHENS AND INHIBITS CONVECTIVE
DEVELOPMENT. SKIES SHOULD SCATTER OUT WITH TEMPERATURES RISING
WELL INTO THE 80S BY TUESDAY AFTERNOON ALONG WITH CONTINUED HUMID
CONDITIONS AS DEWPOINTS REMAIN NEAR 70 DEGREES. A THIRD AND
STRONGER SHORTWAVE WILL EJECT FROM THE SOUTHERN PLAINS INTO THE
MID SOUTH BY TUESDAY EVENING. THIS SHORTWAVE SHOULD TAKE ON A
NEGATIVE TILT AS IT PROGRESSES ACROSS THE MID SOUTH TUESDAY NIGHT
INTO WEDNESDAY MORNING. AS THIS OCCURS...THE CAPPING INVERSION
WILL BEGIN TO ERODE ALLOWING FOR NUMEROUS THUNDERSTORMS TO DEVELOP
OVER WESTERN SECTIONS OF THE MID SOUTH LATE TUESDAY AFTERNOON.
THUNDERSTORMS SHOULD QUICKLY SPREAD NORTHEAST ACROSS THE REGION
TUESDAY NIGHT INTO WEDNESDAY MORNING. THE ATMOSPHERE SHOULD REMAIN
MODERATELY UNSTABLE THROUGH TUESDAY NIGHT WITH SBCAPE VALUES
RANGING FROM 1500-2500 J/KG...LI/S -6C TO -10C...AND MID LEVEL
LAPSE RATES GREATER THAN 7.0 C/KM. IN ADDITION...DEEP LAYER SHEAR
SHOULD STRENGTHEN AHEAD OF THE SHORTWAVE AS A 40-50 KT LOW LEVEL
JET OVERSPREADS THE AREA ALONG WITH AROUND 50 KTS OF MID LEVEL
FLOW. INITIAL THUNDERSTORM MODE SHOULD BE A MIX OF SUPERCELLS AND
BOWING LINE SEGMENTS EARLY IN THE CONVECTIVE EVOLUTION THROUGH
TUESDAY EVENING...EVENTUALLY TRANSITIONING TO AN EXPANSIVE QUASI-
LINEAR CONVECTIVE SYSTEM (QLCS). THE PRIMARY SEVERE THREATS WILL
BE DAMAGING WINDS AND LARGE HAIL. A TORNADO THREAT WILL EXIST
EARLY IN THE EVENT MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER
TUESDAY EVENING...ESPECIALLY WITH ANY DISCRETE SUPERCELLS THAT
DEVELOP. ANY TORNADO THREAT SHOULD DIMINISH LATER TUESDAY NIGHT AS
LOW LEVEL FLOW VEERS.

THE LINE OF THUNDERSTORMS SHOULD CONTINUE TO ADVANCE EAST OF THE
MISSISSIPPI RIVER LATER TUESDAY NIGHT INTO WEDNESDAY MORNING. THE
SEVERE WEATHER THREAT SHOULD GRADUALLY DIMINISH LATE TUESDAY NIGHT
INTO WEDNESDAY MORNING AS THE SHORTWAVE LIFTS NORTHEAST OF THE
REGION AND DEEP LAYER SHEAR WEAKENS. CHANCES FOR SHOWERS AND
THUNDERSTORMS SHOULD DIMINISH FROM WEST TO EAST DURING THE DAY ON
WEDNESDAY.

AS THE EARLY WEEK UPPER LEVEL LOW OVER THE CENTRAL HIGH PLAINS
MOVES EAST INTO THE GREAT LAKES BY THE END OF THE WEEK...ANOTHER
SHORTWAVE WILL EJECT SOUTHEAST FROM THE MIDDLE MISSISSIPPI VALLEY
THROUGH THE TENNESSEE VALLEY ON THURSDAY. THIS WILL HELP TO PUSH A
COLD FRONT ACROSS THE FORECAST AREA BY THURSDAY AFTERNOON.
ADDITIONAL SHOWERS AND THUNDERSTORMS MAY DEVELOP AHEAD OF THE
SOUTHWARD ADVANCING COLD FRONT. A FEW STORMS MAY BECOME STRONG AS
DEEP LAYER SHEAR RESTRENGTHENS ACROSS THE AREA. THE FRONT SHOULD PUSH
SOUTH OF THE REGION THURSDAY NIGHT WITH HIGH PRESSURE BUILDING IN.

HIGH PRESSURE SHOULD CONTROL THE MID SOUTH WEATHER FOR FRIDAY INTO
NEXT WEEKEND WITH A RETURN TO DRY AND LESS HUMID WEATHER.
TEMPERATURES WILL DROP BACK TO NEAR SEASONAL LEVELS FOR THE END OF
THE WEEK INTO NEXT WEEKEND.

JLH

&&

.AVIATION...
12Z TAF CYCLE

LOW STRATUS HAS ALREADY DEVELOPED ACROSS THE LOWER MISSISSIPPI
VALLEY EARLY THIS MORNING AND WILL SPREAD INTO ALL TAF SITES
BETWEEN 20/12-16Z. OTHERWISE...VFR CONDITIONS EXPECTED TO PREVAIL
THROUGH MUCH OF THE PERIOD AS CLOUDS MIX OUT BY LATE THIS MORNING
MORNING. SOUTH WINDS WILL INCREASE TO 10-16 KTS SUSTAINED WITH
GUSTS BETWEEN 18-26 KTS...ESPECIALLY AT JBR AND MEM. VCTS POSSIBLE AT
JBR MAINLY AFTER 21/08Z AS A SHORTWAVE TROUGH MOVES ACROSS
PORTIONS OF THE MIDDLE AND LOWER MISSISSIPPI VALLEYS.

CJC
&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  89  74  88  69 /  10  10  30  70
MKL  88  72  88  69 /  10  10  30  70
JBR  89  69  86  66 /  10  40  60  90
TUP  89  71  89  70 /   0  10  20  40

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMEG 200953
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
453 AM CDT MON MAY 20 2013

.DISCUSSION...

A POTENT UPPER LEVEL LOW PRESSURE SYSTEM REMAINS NEARLY STATIONARY
OVER THE CENTRAL HIGH PLAINS EARLY THIS MORNING WITH A DOWNSTREAM
UPPER LEVEL RIDGE OF HIGH PRESSURE EXTENDING FROM THE DEEP SOUTH
ACROSS THE MID SOUTH INTO THE OHIO VALLEY. A LEAD SHORTWAVE
ROTATING THROUGH MISSOURI EARLY THIS MORNING CONTINUES TO LIFT
NORTHEAST WITH THUNDERSTORMS OVER MISSOURI CURRENTLY IN A
WEAKENING PHASE AS THE UPPER SUPPORT LIFTS NORTHEAST OF THE
REGION. THIS CONVECTIVE ACTIVITY WILL LIKELY LEAVE A CONVECTIVE
OUTFLOW BOUNDARY THAT WILL EXTEND ACROSS SOUTH CENTRAL MISSOURI
WESTWARD INTO NORTHEAST OKLAHOMA.

ACROSS THE MID SOUTH...THE UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
KEEP DRY AND VERY WARM WEATHER IN PLACE TODAY. HUMID CONDITIONS
WILL ALSO PERSIST AS DEWPOINTS REMAIN IN THE UPPER 60S THROUGH THE
DAY. HIGH TEMPERATURES SHOULD TOP OUT AROUND 90 DEGREES IN MOST
AREAS. SOME LOW LEVEL STRATUS WILL OVERSPREAD THE REGION EARLY
THIS MORNING FROM THE SOUTH...BUT SHOULD MIX OUT FAIRLY QUICKLY
WITH MOSTLY SUNNY SKIES DEVELOPING BY LATE MORNING.

THE AFOREMENTIONED CONVECTIVE OUTFLOW BOUNDARY TO THE NORTH OF THE
FORECAST AREA WILL LIKELY BECOME A FOCUS FOR RENEWED THUNDERSTORM
DEVELOPMENT LATE THIS AFTERNOON INTO THIS EVENING AS ANOTHER MID
LEVEL SHORTWAVE EJECTS FROM THE SOUTHERN PLAINS INTO THE MID
MISSISSIPPI VALLEY TONIGHT. NUMEROUS THUNDERSTORMS SHOULD DEVELOP
ACROSS THE OZARKS OF SOUTHERN MISSOURI SOUTHWESTWARD INTO CENTRAL
OKLAHOMA BY THIS EVENING. INITIAL THUNDERSTORM MODE SHOULD BEGIN
AS SUPERCELLS BUT GRADUALLY TRANSITION INTO A QUASI-LINEAR
CONVECTIVE SYSTEM (QLCS) AS IT ADVANCES EAST-NORTHEASTWARD
OVERNIGHT. THIS LINE OF STORMS MAY ADVANCE ACROSS PORTIONS OF
NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL AFTER MIDNIGHT. THE
AIRMASS AHEAD OF THIS CONVECTIVE COMPLEX SHOULD REMAIN
SUFFICIENTLY UNSTABLE WITH MLCAPES BETWEEN 1500-2500 J/KG...LI/S
AROUND -6C...AND MID LEVEL LAPSE RATES IN EXCESS OF 7.5 C/KM. IN
ADDITION...DEEP LAYER SHEAR BETWEEN 40-50 KTS WILL SPREAD ACROSS
NORTHWEST PORTIONS OF THE FORECAST AREA OVERNIGHT. THIS
COMBINATION OF SHEAR AND INSTABILITY MAY SUPPORT A CONTINUED
SEVERE THREAT AFTER MIDNIGHT INTO PORTIONS OF NORTHEAST ARKANSAS
AND THE MISSOURI BOOTHEEL. THE PRIMARY THREATS APPEAR TO BE
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO CANNOT BE RULED
OUT BUT SHOULD NOT BE THE PRIMARY SEVERE WEATHER HAZARD AS LOW
LEVEL WINDS VEER LATE TONIGHT. STORMS SHOULD EVENTUALLY WEAKEN
TOWARDS SUNRISE AS THEY APPROACH THE MISSISSIPPI RIVER AND
NORTHWEST TENNESSEE AS THE UPPER SUPPORT LIFTS TO THE NORTHEAST OF
THE CONVECTIVE ACTIVITY. THIS ACTIVITY SHOULD EVENTUALLY FIZZLE
LATER TUESDAY MORNING OVER NORTHWEST PORTIONS OF THE MID SOUTH.

THE UPPER RIDGE SHOULD TEMPORARILY REBUILD OVER THE MID SOUTH
DURING THE DAY TUESDAY BRINGING A LULL IN ANY CONVECTIVE ACTIVITY
AS THE CAPPING INVERSION STRENGTHENS AND INHIBITS CONVECTIVE
DEVELOPMENT. SKIES SHOULD SCATTER OUT WITH TEMPERATURES RISING
WELL INTO THE 80S BY TUESDAY AFTERNOON ALONG WITH CONTINUED HUMID
CONDITIONS AS DEWPOINTS REMAIN NEAR 70 DEGREES. A THIRD AND
STRONGER SHORTWAVE WILL EJECT FROM THE SOUTHERN PLAINS INTO THE
MID SOUTH BY TUESDAY EVENING. THIS SHORTWAVE SHOULD TAKE ON A
NEGATIVE TILT AS IT PROGRESSES ACROSS THE MID SOUTH TUESDAY NIGHT
INTO WEDNESDAY MORNING. AS THIS OCCURS...THE CAPPING INVERSION
WILL BEGIN TO ERODE ALLOWING FOR NUMEROUS THUNDERSTORMS TO DEVELOP
OVER WESTERN SECTIONS OF THE MID SOUTH LATE TUESDAY AFTERNOON.
THUNDERSTORMS SHOULD QUICKLY SPREAD NORTHEAST ACROSS THE REGION
TUESDAY NIGHT INTO WEDNESDAY MORNING. THE ATMOSPHERE SHOULD REMAIN
MODERATELY UNSTABLE THROUGH TUESDAY NIGHT WITH SBCAPE VALUES
RANGING FROM 1500-2500 J/KG...LI/S -6C TO -10C...AND MID LEVEL
LAPSE RATES GREATER THAN 7.0 C/KM. IN ADDITION...DEEP LAYER SHEAR
SHOULD STRENGTHEN AHEAD OF THE SHORTWAVE AS A 40-50 KT LOW LEVEL
JET OVERSPREADS THE AREA ALONG WITH AROUND 50 KTS OF MID LEVEL
FLOW. INITIAL THUNDERSTORM MODE SHOULD BE A MIX OF SUPERCELLS AND
BOWING LINE SEGMENTS EARLY IN THE CONVECTIVE EVOLUTION THROUGH
TUESDAY EVENING...EVENTUALLY TRANSITIONING TO AN EXPANSIVE QUASI-
LINEAR CONVECTIVE SYSTEM (QLCS). THE PRIMARY SEVERE THREATS WILL
BE DAMAGING WINDS AND LARGE HAIL. A TORNADO THREAT WILL EXIST
EARLY IN THE EVENT MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER
TUESDAY EVENING...ESPECIALLY WITH ANY DISCRETE SUPERCELLS THAT
DEVELOP. ANY TORNADO THREAT SHOULD DIMINISH LATER TUESDAY NIGHT AS
LOW LEVEL FLOW VEERS.

THE LINE OF THUNDERSTORMS SHOULD CONTINUE TO ADVANCE EAST OF THE
MISSISSIPPI RIVER LATER TUESDAY NIGHT INTO WEDNESDAY MORNING. THE
SEVERE WEATHER THREAT SHOULD GRADUALLY DIMINISH LATE TUESDAY NIGHT
INTO WEDNESDAY MORNING AS THE SHORTWAVE LIFTS NORTHEAST OF THE
REGION AND DEEP LAYER SHEAR WEAKENS. CHANCES FOR SHOWERS AND
THUNDERSTORMS SHOULD DIMINISH FROM WEST TO EAST DURING THE DAY ON
WEDNESDAY.

AS THE EARLY WEEK UPPER LEVEL LOW OVER THE CENTRAL HIGH PLAINS
MOVES EAST INTO THE GREAT LAKES BY THE END OF THE WEEK...ANOTHER
SHORTWAVE WILL EJECT SOUTHEAST FROM THE MIDDLE MISSISSIPPI VALLEY
THROUGH THE TENNESSEE VALLEY ON THURSDAY. THIS WILL HELP TO PUSH A
COLD FRONT ACROSS THE FORECAST AREA BY THURSDAY AFTERNOON.
ADDITIONAL SHOWERS AND THUNDERSTORMS MAY DEVELOP AHEAD OF THE
SOUTHWARD ADVANCING COLD FRONT. A FEW STORMS MAY BE STRONG STORMS
MAY AGAIN BE POSSIBLE AS DEEP LAYER SHEAR RESTRENGTHENS. THE FRONT
SHOULD PUSH SOUTH OF THE REGION THURSDAY NIGHT WITH HIGH PRESSURE
BUILDING IN.

HIGH PRESSURE SHOULD CONTROL THE MID SOUTH WEATHER FOR FRIDAY INTO
NEXT WEEKEND WITH A RETURN TO DRY AND LESS HUMID WEATHER.
TEMPERATURES WILL DROP BACK TO NEAR SEASONAL LEVELS FOR THE END OF
THE WEEK INTO NEXT WEEKEND.

JLH

&&

.AVIATION...

06Z TAF CYCLE

VFR CONDS WILL PREVAIL OVERNIGHT. STRATUS IS DEVELOPING ACROSS THE
LOWER MS VALLEY AND WILL SPREAD NORTH INTO THE MIDSOUTH EARLY
MONDAY MORNING. STRATUS WILL GRADUALLY BREAK UP WITH CONDS
BECOMING VFR AFT 20/16Z. SOUTH WINDS AT 8-12 KTS TONIGHT WILL
INCREASE TO 10-16 KTS MONDAY MORNING WITH HIGHER GUSTS ESPECIALLY
AT KJBR AND KMEM.

SJM

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  89  74  88  69 /  10  10  30  70
MKL  88  72  88  69 /  10  10  30  70
JBR  89  69  86  66 /  10  40  60  90
TUP  89  71  89  70 /   0  10  20  40

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$

000
FXUS64 KMRX 200831 AAA
AFDMRX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
431 AM EDT MON MAY 20 2013

.DISCUSSION...THE SATURATED AIRMASS AND CLEARING SKIES HAVE ALLOWED
AREAS OF DENSE FOG TO DEVELOP EARLY THIS MORNING. AREA OBSERVATIONS
AND WEB-CAMS SHOW A GOOD DEAL OF DENSE FOG ACROSS THE AREA. DUE TO
MORE CLOUDS OVER SOUTHWEST VIRGINIA AND NORTHEAST TENNESSEE..ONLY
PATCHY DENSE FOG ANTICIPATED. HAVE ISSUED A DENSE FOG ADVISORY FOR
SOUTHWEST NORTH CAROLINA AND CENTRAL AND SOUTHERN SECTIONS OF EAST
TENNESSEE THROUGH MID-M0RNING.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             87  66  90  67  85 /  10  10  20  20  60
KNOXVILLE MCGHEE TYSON AIRPORT, TN  85  65  88  66  83 /  20  10  20  20  60
OAK RIDGE, TN                       86  65  87  66  83 /  20  20  20  20  60
TRI CITIES AIRPORT, TN              82  57  85  60  82 /  40  20  30  20  50

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR THE
     FOLLOWING ZONES: CHEROKEE...CLAY.

TN...DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR
     THE FOLLOWING ZONES: ANDERSON...BLEDSOE...BLOUNT SMOKY
     MOUNTAINS...BRADLEY...CAMPBELL...CLAIBORNE...COCKE SMOKY
     MOUNTAINS...EAST POLK...GRAINGER...HAMBLEN...HAMILTON...
     JEFFERSON...KNOX...LOUDON...MARION...MCMINN...MEIGS...
     MORGAN...NW BLOUNT...NORTH SEVIER...NORTHWEST COCKE...
     NORTHWEST MONROE...RHEA...ROANE...SCOTT TN...SEQUATCHIE...
     SEVIER SMOKY MOUNTAINS...SOUTHEAST MONROE...UNION...WEST
     POLK.

VA...NONE.

&&

$$