741 
FXUS64 KMEG 210040 AAB
AFDMEG

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MEMPHIS TN
640 PM CST WED FEB 20 2013

.UPDATE...

UPDATED TO INCLUDE 00Z AVIATION DISCUSSION BELOW.

JCL

&&

.DISCUSSION... /ISSUED 325 PM CST WED FEB 20 2013/

A LOT OF WEATHER TO TALK ABOUT IN THE SHORT TERM AS LATE WINTER
STORM EJECTS OUT OF THE SOUTHERN ROCKIES TONIGHT AND TRACKS
THROUGH THE PLAINS TOMORROW. FIRST...MOISTURE LIFTING UP OVER THE
850MB WARM FRONT HAS BEN QUITE LIGHT THANKS TO DEWPOINTS IN THE
SINGLE DIGITS AND TEENS. THE PRECIPITATION THAT HAS REACHED THE
GROUND HAS BEEN A RAIN AND SLEET MIX DUE TO WET-BULBING EFFECTS
BEGINNING FROM NEAR 700MB AND ON DOWN. THE THREAT OF A RAIN AND/OR
WINTER MIX WILL CONTINUE THROUGH THE EVENING AND OVERNIGHT
HOURS...WITH THE GREATEST PROBABILITY OF MEASURABLE PRECIPITATION
OCCURRING WEST OF THE MS RIVER AND NORTH OF INTERSTATE FORTY. THIS
AREA HAS STRUGGLED TO REACH FREEZING AND WILL LIKELY DROP TO THE
UPPER 20S AS PRECIPITATION STARTS. A WINTER WEATHER ADVISORY IS IN
EFFECT STARTING AT 9 PM FOR NORTHEAST ARKANSAS AND THE BOOTHEEL OF
MISSOURI. NOTE THOUGH...IF THE PRECIPITATION CURRENTLY IN WESTERN
ARKANSAS CAN HOLD TOGETHER THIS ADVISORY MAY HAVE TO BE EXTENDED
FURTHER EAST INTO PORTIONS OF WEST TENNESSEE. THE EVENING SHIFT
WILL OF COURSE MONITOR THIS POSSIBILITY.

THE BRUNT OF PRECIPITATION WITH THE DEEPENING STORM IS NOT LIKELY
TO ARRIVE UNTIL AFTER SUNRISE THURSDAY. THE NAM AND GFS BOTH HIT ON A
TONGUE OF SUBFREEZING AIR REMAINING ACROSS NORTHEAST ARKANSAS AND
THE BOOTHEEL OF MISSOURI...WITH THE GFS A BIT MORE BULLISH ON QPF
AMOUNTS. IT'S ALSO INTERESTING TO SEE THE GFS HINTING AT COLD-AIR
DAMMING BETWEEN THE OZARKS AND CROWLEY'S RIDGE WITH SURFACE WINDS
BACKED MORE NORTHEASTERLY DURING THE DAY. FOR THIS REASON...HEAVIER
AMOUNTS AND LONGER PERIOD OF FREEZING RAIN ARE EXPECTED OVER
RANDOLPH...LAWRENCE...CLAY AND GREENE COUNTIES WITH ICE
ACCUMULATIONS EXCEEDING A QUARTER OF AN INCH...PROMPTING THE ICE
STORM WARNING. LOCALLY THERE MAY BE ICE AMOUNTS OF UP TO THREE
QUARTERS OF INCH. BY MID-AFTERNOON MODELS INDICATE THE TRAPPED
COLD AIR WILL ERODE OUT ENOUGH TO ALLOW SURFACE TEMPERATURES TO
CLIMB TO JUST ABOVE FREEZING WITH A CHANGE-OVER TO ALL RAIN. THIS
MAY HELP MITIGATE SOME OF THE STORM'S EXPECTED IMPACTS.

FURTHER SOUTH AND EAST A COLD RAIN IS ANTICIPATED WITH BREEZY
EAST TO SOUTHEAST WINDS. AS A WEAK TRIPLE LOW DEVELOPS OVER THE
LOWER MISSISSIPPI VALLEY HIGH TEMPERATURES IN THE MID 50S MAY
REACH INTO NORTHEAST MISSISSIPPI...OTHERWISE MOST LOCATIONS WILL
REMAIN IN THE 40S. FEEL THE THREAT FOR A STRONG TO SEVERE STORM IS
FURTHER SOUTH THEN THE CURRENT SPC OUTLOOK AS MODELS INDICATE
NEGATIVE LI'S REMAINING SOUTH OF INTERSTATE TWENTY. FOR NOW...HAVE
ONLY THE MENTION OF ISOLATED THUNDER ACROSS NORTH MISSISSIPPI FOR
THE LATE AFTERNOON AND EVENING HOURS. AS THE STORM LIFTS INTO THE
THE GREAT LAKES A COLD FRONT WILL PASS THROUGH THE AREA EARLY
FRIDAY MORNING. AND SINCE THIS STORM IS OF THE WARM OCCLUSION TYPE
THE AIRMASS BEHIND THE COLD FRONT WILL BE MILD. TEMPERATURES ON
FRIDAY WILL BE WARMER FOR MOST OF THE MIDSOUTH...WITH THE
EXCEPTION OF WHERE SIGNIFICANT ICE HAS FALLEN. HAVE GONE WELL
BELOW MODEL GUIDANCE OVER NORTHEAST ARKANSAS FOR THIS REASON WITH
HIGHS ONLY IN THE LOW 40S. ELSEWHERE HIGHS WILL BE IN THE 50S AND
60S. LOWS WILL FALL TO AT OR BELOW FREEZING WITH MOSTLY CLEAR SKIES
FRIDAY NIGHT.

LONG TERM...(SATURDAY THROUGH WEDNESDAY)...00Z/12Z GFS AND 00Z 
ECMWF LONG TERM MODELS INDICATE A WEAK UPPER LEVEL RIDGE BUILDING IN 
ACROSS THE MID SOUTH FOR SATURDAY INTO SUNDAY. HOWEVER...ANOTHER 
UPPER LEVEL LOW IS EXPECTED TO DEVELOP IN THE CENTRAL PLAINS AND 
MOVE EAST NORTHEAST ACROSS THE MIDDLE MISSISSIPPI BY MONDAY AND INTO 
THE GREAT LAKES REGION BY TUESDAY. MEANWHILE...AT THE SURFACE A COLD 
FRONT WILL GRADUALLY BEGIN TO OCCLUDE AS IT APPROACHES THE LOWER 
MISSISSIPPI VALLEY ON MONDAY. A FEW THUNDERSTORMS WILL BE POSSIBLE 
DURING THE DAY ON MONDAY...ESPECIALLY SOUTH OF I-40 AND NOT 
ANTICIPATING STRONG TO SEVERE THUNDERSTORMS AT THIS TIME. 
PRECIPITATION FREE WEATHER IS ANTICIPATED TO RETURN FOR THE 
REMAINDER OF THE LONG TERM FORECAST. TEMPERATURES THIS WEEKEND INTO 
NEXT WEEK WILL AVERAGE NEAR NORMAL TO SLIGHTLY BELOW NORMAL FOR 
FEBRUARY.

JAB/CJC

&&

.AVIATION...

00Z TAF CYCLE (21/00Z-21/02Z)

DIFFICULT FORECAST WITH PRECIP TYPE ISSUES. BAND OF LIGHT RAIN AND
LIGHT SLEET HAS SPREAD INTO EAST AR AND PORTIONS OF SOUTHWEST TN
AND NORTH MS. HAVE INCLUDED MENTION OF -PL AT KJBR...KMEM...AND
KMKL THIS EVENING. ALSO ISSUED AN AIRPORT WEATHER WARNING FOR THE
MEMPHIS INTERNATIONAL AIRPORT UNTIL 9 PM CST FOR THE LIGHT
SLEET...THE CRITERIA FOR ISSUANCE IS ANY ACCUMULATION OF SLEET.
HAVE KJBR GOING TO FREEZING RAIN LATE TONIGHT AS THE UPPER LEVELS
SLOWLY WARM. KJBR MAY RECEIVE BETWEEN 1/10 AND 2/10 OF ICE
ACCUMULATION BEFORE CHANGING TO RAIN LATE THURSDAY MORNING. MAY
INCLUDE FREEZING RAIN IN KMKL LATER TONIGHT BUT FOR NOW THIS IS
UNCERTAIN. KEPT THE PRECIP NORTH OF KTUP TONIGHT. WHERE THE PRECIP
OCCURS TONIGHT...IT IS EXPECTED TO BE ON THE LIGHT SIDE WITH VFR
CEILINGS AND VISIBILITIES PERSISTING AT THE TAF SITES.

HEAVIER RAIN IS FORECAST TO SPREAD ACROSS THE MIDSOUTH FROM THE
WEST AFTER 21/17Z. CONDITIONS LOWERING TO MVFR AND AFTERWARDS 
QUICKLY LOWERING TO IFR. ALSO INCLUDED VCTS AT KTUP AFTER 21/20Z AS 
ELEVATED INSTABILITY PUSHES INTO THIS REGION.

NE-E WINDS TONIGHT 10-12 KTS...E-SE WINDS THURSDAY 12-15 KTS.

JCL

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  32  46  39  56 /  50  90  70  10 
MKL  28  46  39  58 /  30  90  80  20 
JBR  28  36  32  47 /  60  90  50  20 
TUP  30  53  46  67 /  20  80  80  10 

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...ICE STORM WARNING FROM 6 AM TO 3 PM CST THURSDAY FOR CLAY-GREENE-
     LAWRENCE-RANDOLPH.

     WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR CLAY-GREENE-
     LAWRENCE-RANDOLPH.

     WINTER WEATHER ADVISORY UNTIL 9 AM CST THURSDAY FOR CRITTENDEN-
     LEE AR-PHILLIPS-ST. FRANCIS.

     WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR CRAIGHEAD-
     CROSS-MISSISSIPPI-POINSETT.

MO...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR DUNKLIN-
     PEMISCOT.

MS...WINTER WEATHER ADVISORY UNTIL 9 AM CST THURSDAY FOR ALCORN-
     BENTON MS-DESOTO-MARSHALL-PRENTISS-TATE-TIPPAH-TISHOMINGO-
     TUNICA.

TN...WINTER WEATHER ADVISORY UNTIL 9 AM CST THURSDAY FOR CHESTER-
     DECATUR-FAYETTE-HARDEMAN-HARDIN-HAYWOOD-HENDERSON-
     LAUDERDALE-MADISON-MCNAIRY-SHELBY-TIPTON.

&&

$$