Special Weather Statement, NWS Memphis, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
720 PM CST SAT DEC 8 2012

.UPDATE...
UPDATED WEATHER GRIDS FOR THIS EVENING AND OVERNIGHT

&&

.DISCUSSION...

SHOWERS AND FEW EMBEDDED THUNDERSTORMS THIS EVENING HAVE DEVELOPED
ALONG AND SOUTH OF THE I-40 CORRIDOR MAINLY IN RESPONSE TO A
SUBTROPICAL JET STREAK RUNNING FROM CENTRAL TEXAS TO THE MS/LA
BORDER. HAVE ADJUSTED THE EVENING WEATHER GRIDS TO REMOVE THE
MENTION OF THUNDER ACROSS THE NORTHERN COUNTIES DESPITE A
STATIONARY FRONT LYING IN THE AREA. HOWEVER...FEEL THAT THE
THUNDERSTORM FOCUS WILL SHIFT NORTH TO THIS REGION LATER TONIGHT AS
THE DIVERGENCE INCREASES FROM BOTH THE JET STREAK AND THE
APPROACHING DIGGING SHORTWAVE IN SOUTH DAKOTA.

HAVE ALSO ADDED PATCHY DRIZZLE ACROSS THE ENTIRE MIDSOUTH THIS EVENING.

JAB

&&

.PREV DISCUSSION... /ISSUED 548 PM CST SAT DEC 8 2012/

.UPDATE...
UPDATED FOR AVIATION.

PREV DISCUSSION... /ISSUED 325 PM CST SAT DEC 8 2012/

DISCUSSION...16Z SURFACE ANALYSIS PLACES A QUASI-STATIONARY
BOUNDARY FROM CINCINNATI BACK THROUGH WESTERN KENTUCKY...THE
MISSOURI BOOTHEEL...NORTHEAST ARKANSAS...THEN BACK THROUGH
SOUTHWEST ARKANSAS AND NORTHEAST TEXAS. SHOWERS AND THUNDERSTORMS
HAVE BEEN PREDOMINANTLY CONFINED TO PORTIONS OF WEST TENNESSEE AND
NORTHEAST MISSISSIPPI NEAR THE TENNESSEE RIVER AS BEST FORCING
HAS DEPARTED THE MID SOUTH TEMPORARILY. TEMPERATURES AS OF 2 PM
CST RANGE FROM AROUND 70 DEGREES NEAR TUPELO...LOWER 60S ALONG THE
I-40 CORRIDOR...AND UPPER 50S ACROSS NORTHEAST ARKANSAS. STRONG THUNDERSTORM
POTENTIAL TONIGHT AND STRONG TO SEVERE THUNDERSTORMS LATE SUNDAY
AFTERNOON INTO SUNDAY EVENING ARE THE PREDOMINANT FORECAST
CONCERNS IN THIS AFTERNOON/S FORECAST ISSUANCE.

SHORT TERM...(TONIGHT THROUGH TUESDAY)...A QUASI-STATIONARY FRONT
CURRENTLY BISECTING THE MID SOUTH THIS AFTERNOON WILL GRADUALLY
BEGIN TO MOVE NORTH AS A WARM FRONT TONIGHT. SUBTLE MID LEVEL
SHORTWAVE TROUGHS EMBEDDED WITHIN SOUTHWEST FLOW ALOFT WILL MOVE
ACROSS THE MIDDLE/LOWER MISSISSIPPI VALLEYS TONIGHT...RESULTING IN
A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE MID SOUTH...ESPECIALLY
ALONG AND NORTH OF I-40. ANY THUNDERSTORMS ARE EXPECTED TO BE
ELEVATED WITH PERHAPS A STRONG ELEVATED THUNDERSTORM OR TWO
POSSIBLE. SMALL HAIL WOULD BE THE THREAT WITH ANY STRONG
THUNDERSTORMS. IN ADDITION TO A POTENTIAL STRONG THUNDERSTORM
THREAT TONIGHT...TEMPERATURES HAVE NOT RECOVERED MUCH ALONG AND
NORTH OF I-40 TODAY AND WINDS REMAIN RELATIVELY LIGHT. THUS...A
POTENTIAL FOR PATCHY FOG WILL EXIST UNTIL WINDS INCREASE LATER
TONIGHT AS THE QUASI-STATIONARY FRONT BEGINS TO MOVE NORTH AS A
WARM FRONT.

THE ABOVE MENTIONED WARM FRONT WILL CONTINUE TO PUSH NORTH ACROSS
THE MIDDLE MISSISSIPPI VALLEY ON SUNDAY AS AN AREA OF LOW PRESSURE
IN THE SOUTHERN PLAINS MOVES ACROSS THE SOUTHERN HALF OF MISSOURI.
THIS WILL BRING A TRAILING COLD FRONT THROUGH A MAJORITY OF THE
MID SOUTH SUNDAY EVENING AND ACROSS THE REMAINDER OF NORTHEAST
MISSISSIPPI LATE SUNDAY NIGHT. DECENT 500 MB LEVEL HEIGHT
FALLS...SUFFICIENT UPPER LEVEL DIVERGENCE PRODUCED BY A 130 KT 300
MB UPPER LEVEL JET STREAK...FAVORABLE NEARLY UNIDIRECTIONAL UPPER
LEVEL WINDS ALOFT...MOST UNSTABLE CAPE VALUES BETWEEN 800-1000
J/KG...LI/S BETWEEN -3 TO -5...AND MODERATELY STEEP 700-500 MB
LAYER MID LEVEL LAPSE RATES SUGGEST SOME STRONG TO SEVERE
THUNDERSTORMS MAY BE POSSIBLE ACROSS THE MID SOUTH LATE SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE BEST CHANCE FOR STRONG TO
SEVERE THUNDERSTORMS WILL BE ACROSS AREAS ALONG AND SOUTH OF I-40
IN THE MISSISSIPPI RIVER DELTA LATE AFTERNOON INTO EARLY
EVENING...WITH A GRADUAL DIMINISHING THREAT BEING CONFINED
PREDOMINANTLY ACROSS NORTH MISSISSIPPI THROUGH THE REMAINDER OF
THE NIGHT. ANY THUNDERSTORMS WHICH REACH SEVERE LIMITS WILL
PRODUCE DAMAGING WINDS ALONG WITH A SECONDARY THREAT OF LARGE HAIL
AS MID LEVEL TEMPERATURES COOL TO -15 TO -18C.

MUCH COLDER ARCTIC AIR WILL BEGIN TO MOVE INTO THE LOWER
MISSISSIPPI VALLEY ON MONDAY AS PRECIPITATION GRADUALLY COMES TO AN
END ACROSS THE ENTIRE MID SOUTH LATE MONDAY AFTERNOON INTO EARLY
MONDAY EVENING. 12Z WRF MODEL SOUNDINGS INDICATE A POTENTIAL FOR A
RAIN/SLEET MIX TOWARDS 12Z MONDAY ACROSS PORTIONS OF NORTHEAST
ARKANSAS AROUND WALNUT RIDGE. AT THE SAME TIME...SHORT TERM MODELS
INDICATE ANOTHER SURFACE LOW WILL MOVE ACROSS THE LOWER MISSISSIPPI
VALLEY ALONG THE FRONT MONDAY...WHICH MAY BRIEFLY SLOW THE
PROGRESSION OF THE COLD AIR INTO THE MID SOUTH MONDAY. FOR THE
TIME BEING WILL MENTION A CHANCE OF RAIN AND SLIGHT CHANCE OF
SLEET FOR LAWRENCE AND RANDOLPH COUNTIES BETWEEN 09-12Z MONDAY AND
LET MIDNIGHT SHIFT FURTHER EVALUATE WINTER PRECIPITATION TYPE
POTENTIAL AFTER THIS EVENING/S 00Z MODEL RUN ARRIVES.
NONETHELESS...POST-FRONTAL RAIN IS EXPECTED ACROSS MUCH OF THE MID
SOUTH ON MONDAY.

VERY COLD ARCTIC HIGH PRESSURE IS EXPECTED TO BUILD INTO THE
LOWER MISSISSIPPI VALLEY MONDAY NIGHT...RESULTING IN CLEARING
SKIES AND TEMPERATURES FALLING BACK INTO THE 20S ACROSS MANY
LOCATIONS BOTH MONDAY NIGHT AND TUESDAY NIGHT.

LONG TERM...(WEDNESDAY THROUGH SATURDAY)...12Z GFS/ECMWF LONG
TERM MODELS INDICATE SURFACE AND UPPER LEVEL RIDGING WILL REMAIN
IN PLACE ACROSS THE MID SOUTH FOR WEDNESDAY WITH A GRADUAL
MODERATION OF TEMPERATURES TOWARDS NEXT WEEKEND AS HIGH PRESSURE
MOVES EAST. ANOTHER AREA OF LOW PRESSURE AND ASSOCIATED COLD FRONT
IS ANTICIPATED TO MOVE THROUGH THE MISSISSIPPI VALLEY NEXT FRIDAY
AND SATURDAY...BRINGING A RETURN OF SHOWERS AND PERHAPS
THUNDERSTORMS BACK TO THE REGION.

CJC

&&

.AVIATION...
00Z TAFS

MVFR/IFR TO PREVAIL THROUGH MUCH OF THE EVENING AND OVERNIGHT. AN
AREA OF LOWER IFR CIGS EXTENDED UP THE MS RIVER DELTA AT 00Z WILL
LIKELY KEEP MEM IFR INTO MIDEVENING. CONFIDENCE IS NOT HIGH THAT
THIS DECK WILL SCATTER OUT...BUT WILL KEEP A FEW HOURS OF LATE
EVENING MVFR IN... CARRIED OVER FROM THE PREVIOUS TAFS.

PWB

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  59  73  44  45 /  60  60 100  60
MKL  56  71  44  44 /  70  50 100  60
JBR  56  69  38  41 /  70  70  90  40
TUP  57  73  54  54 /  50  30 100  90

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MEMPHIS TN
737 PM CST SAT DEC 8 2012

ARZ008-009-017-018-026>028-035-036-048-049-058-MOZ113-115-
MSZ001>017-020>024-TNZ001>004-019>021-048>055-088>092-100345-
ALCORN-BENTON MS-CALHOUN-CARROLL-CHESTER-CHICKASAW-CLAY-COAHOMA-
CRAIGHEAD-CRITTENDEN-CROCKETT-CROSS-DESOTO-DECATUR-DUNKLIN-DYER-
FAYETTE-GIBSON-GREENE-HARDEMAN-HARDIN-HAYWOOD-HENDERSON-HENRY-
ITAWAMBA-LAFAYETTE-LAKE-LAUDERDALE-LAWRENCE-LEE AR-LEE MS-MADISON-
MARSHALL-MCNAIRY-MISSISSIPPI-MONROE-OBION-PANOLA-PEMISCOT-
PHILLIPS-POINSETT-PONTOTOC-PRENTISS-QUITMAN-RANDOLPH-SHELBY-
ST. FRANCIS-TALLAHATCHIE-TATE-TIPPAH-TIPTON-TISHOMINGO-TUNICA-
UNION-WEAKLEY-YALOBUSHA-
737 PM CST SAT DEC 8 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST ARKANSAS...
THE MISSOURI BOOTHEEL...NORTH MISSISSIPPI...AND WEST TENNESSEE.

.DAY ONE...TONIGHT

A STRONG THUNDERSTORM OR TWO CONTAINING SMALL HAIL IS POSSIBLE
TONIGHT ACROSS ALL OF THE MIDSOUTH.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE LATE SUNDAY AFTERNOON
INTO SUNDAY NIGHT AS A STRONG COLD FRONT MOVES THROUGH THE MID
SOUTH. THE GREATEST THREAT FOR SEVERE THUNDERSTORMS WILL BE ACROSS
EAST ARKANSAS...SOUTHWEST TENNESSEE...AND NORTH MISSISSIPPI. LARGE
HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS FOR ANY
THUNDERSTORMS THAT REACH SEVERE LIMITS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE SUNDAY AFTERNOON INTO SUNDAY
NIGHT.

JAB

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
800 PM CST SAT DEC 8 2012

MSZ020-090230-
TALLAHATCHIE MS-
800 PM CST SAT DEC 8 2012

...THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY UNTIL 830 PM CST FOR...

  EAST CENTRAL TALLAHATCHIE COUNTY IN NORTHWEST MISSISSIPPI...

A STRONG THUNDERSTORM PRODUCING PEA SIZE HAIL OR LARGER WAS LOCATED 6
MILES SOUTH OF CASCILLA AT 800 PM CST...MOVING NORTH AT 30 MPH.

VERY HEAVY RAIN ALONG WITH CONTINUOUS CLOUD TO GROUND LIGHTNING WILL
OCCUR WITH THIS  THUNDERSTORM.

PEOPLE IN TALLAHATCHIE COUNTY SHOULD MONITOR THIS STORM CLOSELY.

&&

LAT...LON 3382 9007 3394 9001 3394 8993 3384 8991
      3382 8993 3382 8997 3381 8998 3380 9005
TIME...MOT...LOC 0200Z 198DEG 26KT 3378 8998

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
815 PM CST SAT DEC 8 2012

MSZ020>022-090230-
YALOBUSHA MS-TALLAHATCHIE MS-CALHOUN MS-
815 PM CST SAT DEC 8 2012

...THE NATIONAL WEATHER SERVICE IN MEMPHIS HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY UNTIL 830 PM CST FOR...

  WEST CENTRAL CALHOUN COUNTY IN NORTHEAST MISSISSIPPI...
  EXTREME NORTHEASTERN TALLAHATCHIE COUNTY IN NORTHWEST
  MISSISSIPPI...
  YALOBUSHA COUNTY IN NORTHWEST MISSISSIPPI...

A STRONG THUNDERSTORM PRODUCING PENNY TO NICKEL SIZE HAIL WAS
LOCATED 7 MILES SOUTH OF SCOBEY AT 815 PM CST...MOVING NORTHEAST AT
35 MPH.

VERY HEAVY RAIN ALONG WITH CONTINUOUS CLOUD TO GROUND LIGHTNING WILL
OCCUR WITH THIS  THUNDERSTORM.

PEOPLE IN CALHOUN...TALLAHATCHIE AND YALOBUSHA COUNTIES SHOULD
MONITOR THIS STORM CLOSELY.

&&

LAT...LON 3414 8993 3414 8979 3386 8945 3384 8951
      3386 8952 3386 8969 3386 8977 3389 8978
      3389 8992 3383 8992 3382 8993 3383 8994
TIME...MOT...LOC 0215Z 234DEG 32KT 3384 8984