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.
&&
$$
MJB/TG
000
FXUS64 KMRX 201730
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
130 PM EDT MON MAY 20 2013
.AVIATION...WARM AND MOIST AIR WILL REMAIN IN PLACE THROUGH THE TAF
PERIOD. STRONG DAYTIME HEATING WILL HELP DESTABILIZE THE ATMOSPHERE
AND EXPECTED TO SEE DIURNAL CONVECTION DEVELOP DURING THE
AFTERNOON. THE BULK OF THIS ACTIVITY SHOULD STAY OVER HIGHER
TERRAIN AND NOT EXPECTED TO EFFECT AREA TAFS. OVERNIGHT...FOG IS
EXPECTED TO DEVELOP ONCE AGAIN FOR MVFR AND POSSIBLY IFR CONDITIONS
BY SUNRISE.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
000
FXUS64 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.
&&
$$
MJB
000
FXUS64 KMRX 201124
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
724 AM EDT MON MAY 20 2013
.AVIATION...MAIN CONCERN THROUGH 14Z IS THE VLIFR-LIFR CONDITIONS AT
TYS AND CHA DUE TO RADIATIONAL FOG DEVELOPMENT. AT TRI...LIFR CONDITIONS
DUE TO CEILINGS WILL CONTINUE THROUGH 14Z AS WELL.
FOG/LOW-CLOUDS WILL DISSIPATE/LIFT THIS MORNING WITH VFR CONDITIONS
RETURNING BY 16 UTC AT ALL TAF SITES. UPPER LOW THAT MOVED ACROSS
THE TENNESSEE VALLEY TODAY HAS MOVED EAST OF THE AREA WITH RIDING
ALOFT BUILDING OVER THE REGION TODAY AND TONIGHT. ISOLATED
STRONG-SEVERE STORMS ANTICIPATED OVER THE HIGHER TERRAIN THIS
AFTERNOON MOVING INTO THE VALLEY DURING THE EVENING.
FOR TONIGHT...CLEAR SKY AND CONTINUE MOIST GROUND WILL PRODUCE AREAS
OF FOG/LOW-CLOUDS. VLIFR/LIFR CONDITIONS ARE POSSIBLE AT TRI AND TYS AGAIN
EARLY TUESDAY MORNING.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
000
FXUS64 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.
&&
$$
000
FXUS64 KMRX 200739
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
339 AM EDT MON MAY 20 2013
.SHORT TERM...(TODAY AND TONIGHT)...PLENTY OF LOW-LEVEL MOISTURE
AND ENOUGH BREAKS IN THE CLOUDS..ESPECIALLY SOUTHERN HALF OF THE
FORECAST AREA TO PRODUCE AREAS OF FOG..SOME LOCALLY DENSE.
UPPER LOW IS LOCATED ACROSS THE CENTRAL APPALACHIANS THIS MORNING.
WEAK WAVES ROTATING AROUND THE LOW IS FOCUSING THE MODERATE
INSTABILITY TO PRODUCE SCATTERED CONVECTION OVER EAST KENTUCKY INTO
SOUTHWEST VIRGINIA/NORTHEAST TENNESSEE THIS MORNING. DUE TO
CONTINUED HIGH PWS...LOCALLY HEAVY RAINFALL WILL BE THE MAIN
CONCERN TODAY WITH THE GREATEST COVERAGE OVER THE NORTHEAST
SECTIONS OF THE FORECAST AREA. BESIDES THE HEAVY RAIN..ISOLATED
SEVERE STORMS POSSIBLE WITH HAIL UP TO 1 INCH.
ELSEWHERE TODAY...AIRMASS WILL REMAIN MODERATELY UNSTABLE WITH
CAPES OF 2000-2500 J/KG. UPPER RIDGING WILL BE BUILDING INTO THE
TENNESSEE VALLEY BUT NOT ENOUGH CIN TO SUPPRESS CONVECTION. WILL
CALL FOR ISOLATED-WIDELY SCATTERED DIURNAL CONVECTION FOCUSING ON
THE LOCAL TERRAIN. PLENTY OF MID-LEVEL DRY AIR TO BE CONCERN OF
DAMAGING DOWNBURST WINDS FOR THE STRONGEST STORMS..AS WELL AS
MARGINAL HAIL AND LOCALIZED HEAVY RAINFALL.
FOR TONIGHT...LOSS OF DAYTIME HEATING WILL ALLOW CONVECTION TO
DIMINISH THIS EVENING. RADIATIONAL COOLING AND PLENTY OF LOW-LEVEL
MOISTURE WILL PRODUCE PATCHY/AREAS OF FOG. SOME LOCALLY DENSE.
.LONG TERM (TUESDAY THROUGH SUNDAY)...WARM AND MUGGY CONDITIONS CAN
BE EXPECTED THROUGH AT LEAST MID-WEEK AS SOUTHERLY FLOW PERSISTS
AHEAD OF THE LARGE UPPER TROUGH TO THE WEST. THE UPPER TROUGH AND
ASSOCIATED SURFACE LOW PRESSURE WILL MEANDER SLOWLY EASTWARD BY
WEDNESDAY INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE
FORECAST AREA. WILL CONTINUE WITH BEST THUNDERSTORM CHANCES ON WED
AFTERNOON AND THU NIGHT/MORNING. ANOTHER SHOT OF STORMS WILL BE
POSSIBLE THROUGH THE REMAINDER OF THE WEEK UNTIL THE MAIN TROUGH
AXIS PASSES EAST OF THE AREA. THE COLD FRONT THAT WILL MOVE THROUGH
THE REGION ON FRIDAY WILL PROVIDE THE REGION WITH COOLER THAN NORMAL
TEMPERATURES AND A FEW DAYS OF SUNSHINE AND DRY WEATHER.
&&
.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...NONE.
TN...NONE.
VA...NONE.
&&
$$
000
FXUS64 KMRX 200536
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
136 AM EDT MON MAY 20 2013
.AVIATION...MAIN CONCERN THROUGH 12Z IS THE POTENTIAL OF VLIFR-LIFR
CONDITIONS AT TYS AND CHA DUE TO RADIATIONAL FOG DEVELOPMENT. HAVE
INCLUDE IFR CONDITIONS BETWEEN 09-13Z. MORE CLOUD COVER WILL KEEP
FLIGHT CONDITIONS GENERALLY NO LOWER THAN MVFR CONDITIONS.
FOR TODAY..FOG/LOW-CLOUDS DISSIPATE WITH VFR CONDITIONS RETURNING BY
15 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.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AMP
000
FXUS64 KMRX 200135 AAB
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
935 PM EDT SUN MAY 19 2013
.DISCUSSION...
THE HEAVY SHOWERS AND THUNDERSTORMS THAT MOVED ACROSS PORTIONS OF
SOUTHEAST TN...AND FAR NORTHEAST TN/SOUTHWEST VA EARLIER TODAY
HAVE FINALLY WEAKENED WITH THE SETTING SUN AND HAVE MOVED OUT OF
THE FORECAST AREA. THERE STILL REMAINS A REASONABLE CHANCE FOR SOME
LIGHT SHOWERS ALONG THE SPINE OF THE MOUNTAINS AND SOME STRAY
SHOWERS ACROSS THE REST OF THE AREA THROUGH THE REMAINDER OF THE
NIGHT. TEMPERATURES WILL BE ON THE MILD SIDE ONCE AGAIN GIVEN THE
WARM/MOIST AIRMASS IN PLACE AND THE CLOUD COVER...BOTTOMING OUT IN
THE LOW TO MID 60S AGAIN. LATE TONIGHT...AREAS OF FOG DEVELOPMENT
SEEM LIKELY GIVEN THE MOIST BOUNDARY LAYER CONDITIONS...ESPECIALLY
IN SHELTERED AREAS/LOCATIONS NEAR BODIES OF WATER...SO HAVE ADDED A
MENTION OF THIS IN THE GRIDS AFTER 08Z THROUGH 12Z /DAYBREAK/.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 65 88 66 90 67 / 60 20 10 20 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 64 86 64 87 65 / 60 20 10 20 20
OAK RIDGE, TN 64 86 64 87 65 / 30 20 10 20 20
TRI CITIES AIRPORT, TN 61 82 61 85 62 / 60 30 10 20 20
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AMP
000
FXUS64 KMRX 200000 AAA
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
800 PM EDT SUN MAY 19 2013
.AVIATION...
SOME LIGHT SHOWERS WILL LINGER NEAR KCHA FOR THE NEXT FEW HOURS
BEFORE DISSIPATING AFTER SUNSET. VFR CONDITIONS WILL PERSIST
THROUGH MIDNIGHT...BEFORE VIS/CIGS DROP TO MVFR/VFR LEVELS AS MOIST
BOUNDARY LAYER CONDITIONS WILL SUPPORT LIGHT FOG/LOW STRATUS
DEVELOPMENT FROM 07Z THROUGH SUNRISE. THEREAFTER...VFR CONDITIONS
WILL PREVAIL THROUGH THE REMAINDER OF THE PERIOD.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AMP
000
FXUS64 KMRX 191937
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
330 PM EDT SUN MAY 19 2013
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...AN UPPER LEVEL LOW WILL
CONTINUE TO SLOWLY MOVE ACROSS THE SOUTHERN APPALACHIAN REGION
TONIGHT. THIS HAS PRODUCED WIDESPREAD SHOWERS AND THUNDERSTORM INTO
THE OVERNIGHT HOURS. SOME OF THESE STORMS MAY BECOME STRONG TO
SEVERE. THE LOW WILL CONTINUE TO PULL AWAY FROM THE AREA ON
MONDAY...BUT THE AIR MASS WILL REMAIN WARM...MOIST AND AT LEAST
WEAKLY UNSTABLE FOR SCATTERED MAINLY DIURNAL TYPE CONVECTION.
.LONG TERM (TUESDAY THROUGH SUNDAY)...LITTLE CHANGE IN THE WEATHER
PATTERN ON TUESDAY AND EXPECTED ANOTHER DAY OF DIURNAL CONVECTION.
A WEAK FRONTAL BOUNDARY WILL MOVE THROUGH WEDNESDAY FOR OUR BEST
CHANCE OF SHOWERS AND THUNDERSTORMS FOR THE EXTENDED. A TROUGH AXIS
IS PROGGED TO SLIDE THROUGH AROUND THE THURSDAY/FRIDAY TIME FRAME
CONTINUING A CHANCE OF CONVECTION. DRY NORTHWEST FLOW SHOULD SET UP
FOR THE WEEKEND FOR OUR BEST SHOT AT DRY CONDITIONS FOR THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 65 88 66 90 67 / 30 20 10 20 20
KNOXVILLE AIRPORT, TN 64 86 64 87 65 / 50 20 10 20 20
OAK RIDGE, TN 64 86 64 87 65 / 40 20 10 20 20
TRI CITIES AIRPORT, TN 61 82 61 85 62 / 60 30 10 20 20
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
MJB
000
FXUS64 KMRX 191805
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
200 PM EDT SUN MAY 19 2013
.AVIATION...AN UPPER LOW CONTINUES TO SLOWLY TRACK ACROSS THE
SOUTHERN APPALACHIAN REGION TODAY. A WEAK BOUNDARY IN PLACE OVER
MIDDLE TN TO THE CUMBERLAND PLATEAU AS WELL AS INCREASING
INSTABILITY...WILL ALLOW WIDER COVERAGE OF CONVECTION AND ALSO ALLOW
FOR A GREATER CHANCE OF STRONG TO SEVERE THUNDERSTORMS THIS
AFTERNOON. THE UPPER LOW SHOULD BEGIN TO EXIT THE REGION
OVERNIGHT...LEAVING ONLY ISOLATED SHOWERS A POSSIBLY A FEW
THUNDERSTORMS MOVING ACROSS THE TAF SITES DURING THE LATER HALF OF
THE PERIOD. OVERALL...LOW CLOUDS WILL REMAIN BKN TO OVC AND
PREVAILING CONDITIONS WILL BE VFR...BUT EXPECT OCCASIONAL LOWERING
OF CIGS AND VSBYS FOR MVFR CONDITIONS.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
MJB
000
FXUS64 KMRX 191336
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
935 AM EDT SUN MAY 19 2013
.DISCUSSION...
CURRENT SURFACE ANALYSIS SHOWS A NORTH-TO-SOUTH ORIENTED MOISTURE
CONVERGENCE BOUNDARY STRETCHING GENERALLY ALONG THE CUMBERLAND
PLATEAU...WITH DEWPOINTS IN THE LOWER 70S WEST OF IT (OVER MIDDLE TN
AND NORTHERN AL) AND IN THE MID TO UPPER 60S OVER THE FORECAST AREA.
AREA RADARS REVEAL SCATTERED CONVECTION OCCURRING ALONG THIS
CONVERGENCE BOUNDARY...WITH SOME TRAINING CELLS OVER MARION COUNTY
PRODUCING LOCALLY HEAVY RAINFALL. THIS VERY HUMID SUMMER-LIKE AIR
MASS OVER THE FORECAST AREA WILL CONTINUE TO GENERATE SCATTERED
CONVECTION TODAY...AS AN UPPER-LEVEL TROUGH LINGERS OVER THE
SOUTHERN APPALACHIAN REGION. IN FACT...BOTH THE GFS AND NAM MODELS
REVEAL A MODERATELY TO HIGHLY UNSTABLE AIR MASS DEVELOPING TODAY
OVER THE FORECAST AREA...WITH THE BEST INSTABILITY EXPECTED NEAR THE
BOUNDARY OVER THE CUMBERLAND PLATEAU. THIS INSTABILITY SHOULD LEAD
TO THE DEVELOPMENT OF SOME STRONG TO SEVERE TSTORMS THIS AFTERNOON
AND EVENING...ALTHOUGH A FAIRLY WARM MID LEVEL LAYER MAY KEEP THIS
ACTIVITY FROM BECOMING TOO WIDESPREAD. FAIRLY HIGH PRECIPITABLE
WATER VALUES AROUND 1.5 INCHES SHOULD CONTINUE TO PRODUCE SOME
LOCALIZED FLOODING WITH ANY SLOW-MOVING OR TRAINING CONVECTION.
HAVE ALREADY UPDATED THE HAZARDOUS WEATHER OUTLOOK TO BEEF UP THE
WORDING FOR TODAY SOME MORE...AND WILL PLAN TO UPDATE THE ZONE
FORECASTS THIS MORNING TO REMOVE ANY MORNING PRECIP WORDING AND TO
TWEAK TEMPS A LITTLE ACCORDING TO THE LATEST TRENDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 82 65 88 66 89 / 70 30 20 10 20
KNOXVILLE AIRPORT, TN 80 64 87 65 88 / 70 50 20 10 30
OAK RIDGE, TN 80 64 87 65 88 / 60 40 20 10 20
TRI CITIES AIRPORT, TN 78 61 85 60 86 / 70 60 30 10 30
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DMG
000
FXUS64 KMRX 191126
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
726 AM EDT SUN MAY 19 2013
.AVIATION...AN UPPER LOW WILL MOVE ACROSS EAST TENNESSEE
TODAY-TONIGHT. A LOW-LEVEL CONVERGENCE BOUNDARY IS LOCATED ACROSS
THE PLATEAU WHICH IS PRODUCING SCATTERED STRONG TO SEVERE STORMS.
ABUNDANT MOISTURE AND UPPER LOW WILL PRODUCE ANOTHER DAY OF
WIDESPREAD SHOWERS. ALSO...GREATER INSTABILITY WILL PRODUCE STRONGER
STORMS TODAY. MORNING FLIGHT CONDITIONS BETWEEN IFR/MVFR WILL BECOME
VFR THIS AFTERNOON..EXCEPT IN/NEAR STORMS.
FOR TONIGHT..ABUNDANT LOW-LEVEL MOISTURE AND UPPER-LOW MOVING EAST
ALLOWING FOR LESS MID AND HIGH LEVEL CLOUDS WILL PRODUCE BETTER
RADIATIONAL FOG DEVELOPMENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 81 64 88 66 89 / 60 30 10 10 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 79 64 87 65 88 / 60 60 20 10 30
OAK RIDGE, TN 79 65 87 65 88 / 60 50 10 10 20
TRI CITIES AIRPORT, TN 76 59 85 60 86 / 70 70 40 10 30
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
000
FXUS64 KMRX 190747
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
347 AM EDT SUN MAY 19 2013
.SHORT TERM...(TODAY AND TONIGHT)...WEAKENING UPPER TROUGH WILL
CONTINUE TO MOVE SLOWLY EAST ACROSS THE FORECAST AREA TODAY AND
TONIGHT WITH THE AXIS BEING EAST OF THE AREA MONDAY MORNING. PLENTY
OF MOISTURE AND MODERATE INSTABILITY WILL PRODUCE SHOWERS AND
THUNDERSTORMS THROUGH THE SHORT-TERM. MODELS SHOW CAPE OF 1500-2000
J/KG FOR THE PLATEAU WITH LESSER AMOUNTS EAST FOR THIS AFTERNOON-
EVENING. SOUNDINGS SHOW THAT HEAVY RAINFALL WILL ONCE AGAIN BE THE
MAIN THREAT TODAY-TONIGHT WITH MARGINAL HAIL UP TO 1 INCH POSSIBLE
WITH THE STRONGER STORMS.
FOR TONIGHT...ABUNDANT LOW-LEVEL MOISTURE AND CLOUD COVER FROM
UPPER LOW MOVING EAST WILL ALLOW FOR A GOOD AMOUNT OF RADIATIONAL
FOG DEVELOPMENT AREA-WIDE. HAVE INCLUDED AREAS OF FOG FOR
TONIGHT..SOME OF THE FOG WILL LIKELY BE DENSE.
.LONG TERM (MONDAY THROUGH SATURDAY)...BY MONDAY...THE UPPER TROUGH
WILL STILL BE OVER THE CENTRAL PLAINS. THE ASSOCIATED SURFACE LOW
WILL BE CO-LOCATED NEAR NORTHERN NEBRASKA AND BY MONDAY EVENING
EXPECT ANOTHER LOW TO FORM FARTHER SOUTH OVER NE TEXAS. ALL THIS
OCCURRING TO THE WEST WILL HELP DRIVE TEMPERATURES UPWARDS OVER THE
BEGINNING HALF OF THE WEEK AND MAKE CONDITIONS RATHER MUGGY AND
HUMID.
A SHORTWAVE RIDGE OVER OUR AREA ON MONDAY AND TUESDAY WILL
HELP INHIBIT WIDESPREAD THUNDERSTORMS BUT A FEW ISOLATED
SHOWERS/STORMS WILL STILL BE POSSIBLE. IT WILL NOT BE UNTIL THE
AFOREMENTIONED TROUGH TRANSLATES EAST THAT WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL OCCUR...WHICH SHOULD BE BY WEDNESDAY AFTERNOON
AND EVENING. COMPARING THE LONGER RANGE MODELS THIS MORNING ARE
NEARLY OPPOSITE FROM LAST 00Z RUNS. THE GFS IS SLOWER WITH FROPA
LATE THIS WEEK INTO THE WEEKEND...WHILE THE ECMWF IS QUICKER AND
DRIER BY SATURDAY AND SUNDAY. ALTHOUGH BOTH MODELS KEEP RELATIVELY
DRY CONDITIONS INTO THE HOLIDAY WEEKEND AND TEMPERATURES WILL RETURN
TO NEAR NORMAL BY THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 81 64 88 66 89 / 60 30 10 10 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 79 64 87 65 88 / 60 60 20 10 30
OAK RIDGE, TN 79 65 87 65 88 / 60 50 10 10 20
TRI CITIES AIRPORT, TN 76 59 85 60 86 / 70 70 40 10 30
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
000
FXUS64 KMRX 190123 AAB
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
923 PM EDT SAT MAY 18 2013
.DISCUSSION...
VERY MINOR TWEAKS MADE TO THE FORECAST TONIGHT AS EVERYTHING
APPEARS TO BE ON TRACK. A WEAKENING AREA OF LOW PRESSURE WILL
CONTINUE TO TRACK ACROSS THE FORECAST AREA TONIGHT...BRINGING GOOD
OPPORTUNITIES FOR SCATTERED SHOWERS AND PERHAPS AN ISOLATED RUMBLE OF
THUNDER THROUGH LATE EVENING. GIVEN THE HIGH LOW-LEVEL MOISTURE
CONTENT...A LOCALLY HEAVY BURST OF RAINFALL WILL BE POSSIBLE UNDER
THE STRONGEST SHOWERS. SOME LOW-CLOUD DEVELOPMENT IS ALSO EXPECTED
LATER TONIGHT...ALONG WITH SOME LOCALIZED POCKETS OF FOG IN THE
USUAL FOG-PRONE SHELTERED AREAS. OVERNIGHT LOWS WILL GENERALLY
REMAIN IN THE 60S IN MOST VALLEY LOCATIONS OVERNIGHT GIVEN THE
DENSE CLOUD COVER/PRECIPITATION.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 65 83 65 88 67 / 60 60 30 20 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 64 82 64 87 66 / 60 60 40 20 10
OAK RIDGE, TN 65 82 65 87 67 / 60 60 30 20 10
TRI CITIES AIRPORT, TN 59 80 59 85 61 / 70 70 40 30 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AMP
000
FXUS64 KMRX 182343
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
743 PM EDT SAT MAY 18 2013
.AVIATION...
A LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE EAST ACROSS
TN...BRINGING SHOWERS AND ISOLATED THUNDERTORMS THROUGH THE TAF
PERIOD. TIMING AND LOCATION OF ANY THUNDER UNCERTAIN...SO INCLUDED
VCSH AT ALL SITES THROUGH THE PERIOD. WITH THE HIGH MOISTURE
CONTENT...HAVE INCLUDED BR FOR ALL THREE SITES BEGINNING AROUND
06Z. DONT THINK TYS WILL DROP IN WIND SPEED FOR LONG FOG
DEVELOPMENT...SO INCLUDED TEMPO FOR BR BEGINNING AT 08Z.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
JLW
000
FXUS64 KMRX 181911
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
310 PM EDT SAT MAY 18 2013
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...CURRENT SURFACE
ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE OVER THE WESTERN TN RIVER
VALLEY...WITH A WARM AND VERY HUMID AIR MASS OVER THE FORECAST AREA.
AREA RADARS REVEAL SCATTERED CONVECTION DEVELOPING OVER THE FORECAST
AREA THIS AFTERNOON...WHICH SHOULD CONTINUE TO INCREASE IN AREAL
COVERAGE AND INTENSITY AS DAYTIME HEATING COMBINES WITH AN UPPER-
LEVEL TROUGH TO PRODUCE A POTENTIALLY MODERATELY UNSTABLE AIR MASS
OVER THE FORECAST AREA. THE NAM MODEL ONLY REVEALS SOME MARGINAL
INSTABILITY OVER THE FORECAST AREA FOR LATER TODAY AND AGAIN ON
SUNDAY AFTERNOON...BUT THE GFS MODEL INDICATES MODERATE INSTABILITY
DEVELOPING (DUE TO ITS WARMER SURFACE TEMPS) WITH THE POTENTIAL FOR
A HIGHLY UNSTABLE AIR MASS AROUND THE CUMBERLAND PLATEAU ON SUNDAY
AFTERNOON AND AREAWIDE ON MONDAY AFTERNOON. IF THE GFS MODEL
VERIFIES...THINK THAT SOME ISOLATED SEVERE STORMS WILL BE POSSIBLE
ON SUNDAY AFTERNOON AND MONDAY AFTERNOON...WITH THE POSSIBILITY OF
DAMAGING WINDS...LARGE HAIL...AND LOCALLY HEAVY RAINFALL (DUE TO
SLOW-MOVING CONVECTION IN AN ENVIRONMENT WITH PRECIPITABLE WATER
VALUES RANGING BETWEEN 1.5 AND 1.75 INCHES). THIS SLOW-MOVING UPPER-
LEVEL TROUGH WILL FINALLY DRIFT EAST OF THE FORECAST AREA BY
MONDAY...BUT COOLER NORTHWEST FLOW ALOFT BEHIND THE TROUGH WILL HELP
TO DESTABILIZE THE LOCAL AIR MASS ALLOWING FOR ADDITIONAL SCATTERED
CONVECTION TO DEVELOP. AS FOR TEMPS...GFS AND NAM GUIDANCE NUMBERS
ARE IN GENERAL AGREEMENT THROUGH MONDAY NIGHT...BUT WILL COMPROMISE
BETWEEN THE TWO WHERE SOME SLIGHT DIFFERENCES ARE NOTED.
.LONG TERM (TUESDAY THROUGH SATURDAY)...A WARM...MOIST AIRMASS IN
PLACE EARLY IN THE EXTENDED WITH SOUTHWEST FLOW ALOFT. THE RESULT
WILL BE DIURNAL CONVECTION TUESDAY AND WEDNESDAY. BROAD...WEAK
FRONTAL BOUNDARY SLIDES THROUGH AROUND THURSDAY...AND WILL PROVIDE
OUR BEST CHANCE OF CONVECTION. TROUGH AXIS WILL MOVE THOUGH THURSDAY
NIGHT INTO FRIDAY...KEEPING UNSETTLED WEATHER OVER THE AREA.
SATURDAY CURRENTLY LOOKS TO BE OUR BEST SHOT AT A DRY DAY...AS THE
FRONTAL BOUNDARY PULLS AWAY FROM THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 65 83 65 88 67 / 60 60 30 20 10
KNOXVILLE AIRPORT, TN 64 82 64 87 66 / 60 60 40 20 10
OAK RIDGE, TN 65 82 65 87 67 / 60 60 30 20 10
TRI CITIES AIRPORT, TN 59 80 59 85 61 / 70 70 40 30 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DMG/MJB
000
FXUS64 KMRX 181802
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
200 PM EDT SAT MAY 18 2013
.AVIATION...LITTLE CHANGE IN THE WEATHER PATTEN THROUGH THE TAF
PERIOD. A LOW PRESSURE WILL VERY SLOWLY MOVE ACROSS THE SOUTHERN
APPALACHIAN REGION DURING THE NEXT 24 HOURS. THIS LOW WILL CONTINUE
TO GENERATE SCT SHOWERS AND THUNDERSTORMS...PROVIDING OCCASIONAL LOW
CLOUDS AND REDUCED VSBYS FOR MVFR CONDITIONS.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
MJB
000
FXUS64 KMRX 181415
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1015 AM EDT SAT MAY 18 2013
.DISCUSSION...
CURRENT SURFACE ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE CENTERED
OVER WESTERN KY...WITH A WARM AND HUMID SUMMER-LIKE AIR MASS OVER
THE FORECAST AREA. AREA RADARS REVEAL SCATTERED SHOWERS OVER
NORTHEAST TN AND SOUTHWEST VA THIS MORNING...WHICH WERE OCCURRING IN
ASSOCIATION WITH AN UPPER-LEVEL TROUGH OVER THE OHIO AND TN RIVER
VALLEYS. THIS UPPER TROUGH IS PROGGED TO LINGER OVER THE SOUTHERN
APPALACHIANS TODAY...WITH AN UNSTABLE AIR MASS EXPECTED TO DEVELOP
THIS AFTERNOON. NAM MODEL ONLY REVEALS SOME MARGINAL INSTABILITY
DEVELOPING OVER THE FORECAST AREA...BUT THE GFS MODEL INDICATES SOME
MODERATE INSTABILITY DEVELOPING DUE TO ITS WARMER SURFACE TEMPS. IF
THE GFS MODEL VERIFIES...THINK THAT SOME ISOLATED SEVERE STORMS WILL
BE POSSIBLE. THUS...WILL PLAN TO UPDATE THE HAZARDOUS WEATHER
OUTLOOK TO MENTION THE POSSIBILITY OF DAMAGING WIND AND LARGE
HAIL...ALONG WITH THE POSSIBILITY OF LOCALIZED FLOODING DUE TO THE
SLOW-MOVING CONVECTION.
OVERALL...CURRENT FORECAST APPEARS TO BE ON TRACK...BUT WILL UPDATE
THIS MORNING TO REMOVE ANY MORNING PRECIP WORDING AND TO TWEAK TEMPS
A LITTLE ACCORDING TO THE LATEST TRENDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 80 64 82 64 89 / 80 60 60 30 10
KNOXVILLE AIRPORT, TN 78 63 81 63 87 / 90 60 60 30 10
OAK RIDGE, TN 78 64 80 63 87 / 90 60 60 30 10
TRI CITIES AIRPORT, TN 75 58 77 58 85 / 90 70 70 40 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DMG
000
FXUS64 KMRX 181128
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
728 AM EDT SAT MAY 18 2013
.AVIATION...UPPER LOW OVER THE TENNESSEE VALLEY WILL MOVE SLOWLY EAST
THROUGH THE FORECAST PERIOD PRODUCING PERIODS OF SHOWERS AND
AFTERNOON/EVENING THUNDERSTORMS. PLENTY OF MOISTURE WILL PRODUCE
MVFR CONDITIONS AT BOTH CHA AND TYS THIS MORNING DUE TO CEILING AND
VISIBILITY ASSOCIATED WITH RAIN/FOG. VFR CONDITIONS THIS AFTERNOON
WILL BE INTERUPTED BY SCATTERED SHOWERS AND THUNDERSTORMS.
FOR TONIGHT...FLIGHT CONDITIONS WILL DETEORATE WITH LOW-CLOUDS AND
FOG DEVELOPING PRODUCING IFR/MVFR CONDITIONS AT ALL TAF SITES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 79 64 83 64 89 / 80 60 50 20 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 77 62 83 63 87 / 90 60 60 30 10
OAK RIDGE, TN 76 63 82 63 87 / 90 60 60 30 10
TRI CITIES AIRPORT, TN 75 58 80 58 85 / 90 70 70 40 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
000
FXUS64 KMRX 180737
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
337 AM EDT SAT MAY 18 2013
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)...THE MAIN WEATHER
FEATURE WILL BE WEAKENING UPPER TROUGH OVER THE TENNESSEE VALLEY
AND SOUTHERN APPALACHIANS. PERIODS OF SHOWERS AND AFTERNOON AND
EVENING THUNDERSTORMS WILL CONTINUE TODAY THROUGH SUNDAY.
INSTABILITY BECOMES A LITTLE BETTER SUNDAY AS A LITTLE MORE
INSOLATION ANTICIPATED. WILL CONTINUE WITH LIKELY POPS THROUGH MOST
OF THE PERIOD. AREA RAINS AND CLOUDS SLOWLY DIMINISHING THROUGH THE
PERIOD WILL ALLOW FOR RADIATIONAL FOG DEVELOPMENT FOR SATURDAY AND
SUNDAY NIGHTS. WOULD NOT BE SUPRISED TO SEE LOCALLY DENSE FOG.
AS FOR TEMPERATURES FOLLOWED A BLEND OF MET AND GFS MOS..WHICH HAS
WORKED BEST THE PAST COUPLE DAYS.
.LONG TERM (MONDAY THROUGH FRIDAY)...UPPER LEVEL SHORTWAVE RIDGING
WILL OCCUR ON MONDAY WITH CHANCES OF THUNDERSTORMS FOCUSED ON THE
HIGHER TERRAIN OF THE MOUNTAINS OF NE TN AND SW VA. SOUTHERLY LOW
LEVEL FLOW WILL PROVIDE ABUNDANT LOW LEVEL MOISTURE BY TUESDAY. THE
UPPER TROUGH OVER THE NORTHERN PLAINS REMAINS NEARLY STATIONARY
THROUGH WEDNESDAY. THE ASSOCIATED FRONT WILL BE ACROSS WEST
TENNESSEE WEDNESDAY BUT SEEMS TO LOSE ITS IDENTITY BY THURSDAY. THE
MORE DEFINED FRONTAL BOUNDARY WILL BE ACROSS THE NORTHERN OHIO
VALLEY. THE GFS SLOWLY BRINGS THE COOLER AIR INTO THE REGION
SOMETIME FRIDAY WHILE THE ECMWF IS ABOUT 24 TO 36 HOURS SLOWER.
ADDITIONALLY THE ECMWF IS MUCH LESS AMPLIFIED WITH ITS HANDLING OF
THE MID-WEEK UPPER TROUGH AS IT TRACKS IT INTO THE GREAT LAKES
REGION RATHER THAN OVER THE SOUTHERN OHIO VALLEY. WEDNESDAY THROUGH
THURSDAY LOOK LIKE THE BEST CHANCES OF SHOWERS AND THUNDERSTORMS FOR
THIS TIME PERIOD. TEMPERATURES EARLY IN THE WEEK WILL BE WELL ABOVE
NORMAL AND SLOWLY TREND TOWARDS NORMAL BY THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 79 64 83 64 89 / 80 60 50 20 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 77 62 83 63 87 / 90 60 60 30 10
OAK RIDGE, TN 76 63 82 63 87 / 90 60 60 30 10
TRI CITIES AIRPORT, TN 75 58 80 58 85 / 90 70 70 40 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
000
FXUS64 KMRX 180544
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
144 AM EDT SAT MAY 18 2013
.AVIATION...
UPPER LOW MOVING ACROSS THE TENNESSEE VALLEY DURING THE FORECAST
PERIOD. WILL PRODUCE PERIODS OF MVFR/IFR CONDITIONS DUE TO LOWERED
VISIBILITY AND LOW-CLOUDS DUE TO AREAS OF SHOWERS AND THUNDERSTORMS.
THIS IS ESPECIALLY TRUE ACROSS CHA BETWEEN NOW AND 14 UTC. WINDS
WILL BE MAINLY WEST TO SOUTHWEST AROUND 10KTS OR LESS..EXCEPT
IN/NEAR STORMS. SOME OF THE STORMS THIS AFTERNOON/EVENING COULD BE
STRONG/ISOLATED SEVERE. MAIN CONCERN FOR TAF SITES WILL BE STRONG
AND GUSTS WINDS ASSOCIATED WITH THUNDERSTORMS.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
000
FXUS64 KMRX 180152 AAB
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
952 PM EDT FRI MAY 17 2013
.DISCUSSION...
THE LATEST OBS INDICATE SOME ELEVATED INSTABILITY ACROSS THE
REGION...WHICH HAS ALLOWED A FEW CLUSTERS OF THUNDERSTORMS TO
LINGER PAST SUNSET INTO THE MID/LATE EVENING HOURS. HOWEVER...AS
NIGHT SETTLES IN...THINK THAT MOST OF THE THUNDERSTORM ACTIVITY
WILL WANE WITH THE LOSS OF HEATING. HOWEVER...A BROAD AREA OF LIGHT
TO LOCALLY HEAVIER SHOWERS WILL CONTINUE TO WORK ITS WAY INTO THE
FORECAST AREA OVERNIGHT AS AN UPPER-TROUGH MOVES ACROSS THE
SOUTHERN APPALACHIANS. THE BEST CHANCES FOR PRECIPITATION WILL BE
ACROSS THE CUMBERLAND PLATEAU AND SOUTHEAST TENNESSEE AND
EVENTUALLY SPREAD INTO THE CENTRAL/NORTHERN VALLEY AND SOUTHWEST
VIRGINIA LATER TONIGHT. HAVE WENT AHEAD AND GONE DEFINITE POPS ACROSS
THE WESTERN/SOUTHERN THIRD OF THE REGION...BUT HAVE KEPT LIKELY TO
HIGH END CHANCE POPS ELSEWHERE...GIVEN THAT THE HEAVIER
PRECIPITATION GENERALLY SHOULD IMPACT THE WESTERN/SOUTHERN ZONES
BEFORE DAYBREAK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 80 62 78 63 81 / 50 90 80 60 50
KNOXVILLE MCGHEE TYSON AIRPORT, TN 80 61 78 62 80 / 50 70 80 60 60
OAK RIDGE, TN 80 62 78 63 80 / 50 80 80 60 60
TRI CITIES AIRPORT, TN 79 58 76 59 77 / 50 50 80 60 60
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AMP
000
FXUS64 KMRX 180001 AAA
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
801 PM EDT FRI MAY 17 2013
.AVIATION...
WIDELY SCATTERED THUNDERSTORMS THIS EVENING WILL GIVE WAY TO SOME
LIGHT TO PERHAPS MODERATE SHOWERS THIS EVENING AND OVERNIGHT MOVING
IN FROM THE WEST. THIS ACTIVITY SHOULD ARRIVE AT KCHA THIS EVENING
AND EVENTUALLY KTYS/KTRI LATER TONIGHT. LOW VFR TO MVFR CONDITIONS
ARE EXPECTED OVERNIGHT...BEFORE LIFTING AFTER SUNRISE. HOWEVER...
SCATTERED -SHRA WILL BE POSSIBLE FOR THE REMAINDER OF THE
PERIOD AS AN UPPER-TROUGH SWINGS THROUGH. HOWEVER...BASED ON
UNCERTAINTIES IN TIMING...HAVE OPTED TO GO WITH VCSH ATTM.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AMP
000
FXUS64 KMRX 171915
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
315 PM EDT FRI MAY 17 2013
.SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)...CURRENT SURFACE
ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE CENTERED AROUND
MEMPHIS...WITH A WARM AND HUMID AIR MASS OVER THE FORECAST AREA.
AREA RADARS REVEAL ISOLATED CONVECTION DEVELOPING OVER THE FORECAST
AREA THIS AFTERNOON...WHICH SHOULD CONTINUE TO INCREASE IN AREAL
COVERAGE TONIGHT AS AN UPPER-LEVEL TROUGH OVER THE MS RIVER VALLEY
DRIFTS EASTWARD ACROSS THE TN RIVER VALLEY. THIS UPPER TROUGH IS
PROGGED TO MOVE OVER THE FORECAST AREA ON SATURDAY...BRINGING AN
EXTENSIVE AREA OF SHOWERS WITH SOME TSTORMS. THIS UPPER TROUGH WILL
THEN WEAKEN BY SUNDAY...BUT A MARGINALLY TO POTENTIALLY MODERATELY
UNSTABLE AIR MASS IS PROGGED TO DEVELOP OVER THE FORECAST AREA ON
SUNDAY. THUS...WILL MAINTAIN HIGH POPS ON SUNDAY. IT APPEARS THAT
THE SLOW-MOVING CONVECTION EXPECTED THIS WEEKEND MAY LEAD TO SOME
LOCALIZED FLOODING CONCERNS...SINCE PRECIPITABLE WATER VALUES WILL
BE AROUND 1.5 INCHES. AS FOR TEMPS...GFS AND NAM GUIDANCE NUMBERS
ARE IN GOOD AGREEMENT THROUGH SUNDAY NIGHT...AND LOOK REASONABLE.
.LONG TERM (MONDAY THROUGH FRIDAY)...LOW PRESSURE CONTINUE TO PULL
AWAY FROM THE AREA ON MONDAY AND TUESDAY...AS A RIDGE OF HIGH
PRESSURE BUILDS IN. AIDED BY DAYTIME HEATING...CONVECTION SHOULD
REMAIN CONFINED TO FAR NORTHERN/EASTERN LOCATIONS. A WEAK COLD FRONT
WILL MOVE INTO THE REGION AROUND THE WEDNESDAY/THURSDAY TIME FRAME.
MODELS SLOWING THIS FEATURE. WILL LEAVE HIGHEST POPS ON WEDNESDAY...
BUT THIS MAY NEED TO BE PUSHED A BIT LATER IN THE PERIOD IF THE
SLOWING TREND CONTINUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 62 78 63 81 64 / 70 80 60 50 20
KNOXVILLE AIRPORT, TN 61 78 62 80 63 / 60 80 60 60 30
OAK RIDGE, TN 62 78 63 80 64 / 60 80 60 60 30
TRI CITIES AIRPORT, TN 58 76 59 77 60 / 50 80 60 60 40
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DMG/MJB
| 
