376 FXUS64 KMEG 080531 AFDMEG AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 1131 PM CST MON JAN 7 2013 .DISCUSSION... UPDATED FOR THE 06Z AVIATION DISCUSSION && .PREV DISCUSSION... /ISSUED 838 PM CST MON JAN 7 2013/ UPDATE... TEMPERATURES DROPPED OFF QUICKLY AFTER SUNSET AND HAVE ALREADY DROPPED TO NEAR FORECAST MINIMUMS IN SOME LOCATIONS. HIGH LEVEL CLOUDS WILL CONTINUE TO SPREAD ACROSS THE MIDSOUTH FROM THE SOUTHWEST BUT WILL DO LITTLE TO KEEPING TEMPERATURES FROM DROPPING FURTHER WITH LIGHT WINDS. HAVE ALREADY UPDATED THE GRIDS AND ZONE FORECASTS TO DECREASE FORECAST LOW TEMPERATURES SOME IN MOST LOCATIONS...ALSO INCREASED SKY COVER FOR THE REMAINDER OF TONIGHT. JCL DISCUSSION... /ISSUED 347 PM CST MON JAN 7 2013/ HIGH PRESSURE OVER THE TENNESSEE VALLEY WILL SLOWLY MOVE EAST OVER THE NEXT COUPLE OF DAYS AS UPPER LEVEL RIDGING BREAKS DOWN BY MID WEEK. DRY WEATHER WILL CONTINUE TONIGHT INTO TUESDAY WITH TEMPERATURES SEVERAL DEGREES WARMER BY TOMORROW AFTERNOON. A DEEP UPPER LEVEL LOW PRESSURE SYSTEM POSITIONED OVER THE NORTHERN BAJA OF MEXICO THIS AFTERNOON WILL MOVE NORTHEAST OVER THE NEXT SEVERAL DAYS AND WILL BE OUR NEXT WEATHER MAKER FOR MID TO LATE WEEK. AS THE UPPER LOW MOVES INTO TEXAS ON WEDNESDAY EXPECT SURFACE LOW PRESSURE TO ORGANIZE ALONG THE UPPER TEXAS COAST BY WEDNESDAY AFTERNOON. STRENGTHENING LOW LEVEL SOUTHERLY FLOW WILL OVERSPREAD THE MID SOUTH BY WEDNESDAY AFTERNOON...INCREASING MOISTURE AND THERMAL ADVECTIONS. INCREASING LIFT ON THE NOSE OF A 50 KT LOW LEVEL JET PUNCHING INTO THE AREA ALONG WITH MOISTURE OVERRUNNING THE LINGERING CONTINENTAL AIR MASS OVER THE REGION WILL RESULT IN THE DEVELOPMENT OF SCATTERED TO EVENTUALLY NUMEROUS SHOWERS AND ELEVATED THUNDERSTORMS BY WEDNESDAY AFTERNOON AND EVENING. WIDESPREAD RAIN AND THUNDERSTORMS SHOULD CONTINUE WEDNESDAY NIGHT AS SURFACE LOW PRESSURE LIFTS NORTH THROUGH THE ARKLATEX AND LIFTS A SURFACE WARM FRONT ACROSS THE MID SOUTH. AS THE WARM FRONT LIFTS NORTH OF THE REGION ON THURSDAY...MUCH OF THE AREA SHOULD BECOME ENTRENCHED WITHIN A WARM AND MOIST WARM SECTOR CHARACTERIZED BY DEWPOINTS RISING INTO THE LOWER 60S AND TEMPERATURES INTO THE UPPER 60S TO AROUND 70 DEGREES. THIS SHOULD RESULT IN AT LEAST MODEST WARM SECTOR DESTABILIZATION...ALTHOUGH THERE IS STILL SOME QUESTION REGARDING THE OVERALL QUALITY OF THE WARM SECTOR INSTABILITY. ABUNDANT CLOUD COVER AND POTENTIAL RAINFALL COULD SERVE TO LIMIT A MORE WIDESPREAD SEVERE WEATHER EVENT. DEEP LAYER SHEAR SHOULD BECOME QUITE STRONG AHEAD OF THE APPROACHING UPPER LOW AS AN 80 KT MID LEVEL JET ROTATES THROUGH THE REGION. IN ADDITION...STRENGTHENING HELICITY TO THE EAST OF THE SURFACE LOW ACROSS MUCH OF THE WARM SECTOR COMBINED WITH THE POTENTIAL FOR AT LEAST MODEST INSTABILITY WILL AT LEAST SET THE STAGE FOR SOME SEVERE WEATHER ACROSS THE REGION ON THURSDAY. ENVIRONMENTAL CONDITIONS APPEAR TO SUPPORT THE POTENTIAL FOR A MIXED MODE OF SUPERCELLS AND SHORT LINE SEGMENTS THAT WILL POSE A THREAT FOR DAMAGING WINDS AND POSSIBLY A FEW TORNADOES. THE SEVERE WEATHER THREAT SHOULD BE DEPENDENT UPON THE OVERALL AMOUNT OF INSTABILITY THAT WILL BE AVAILABLE. PLAN TO CONTINUE TO MENTION THE POTENTIAL FOR SEVERE THUNDERSTORMS ON THURSDAY AND WILL TREND TOWARDS DEFINING SEVERE WEATHER TYPES AND SPECIFICS OVER THE NEXT DAY OR SO AS MODEL GUIDANCE LOCKS IN ON EXPECTED INSTABILITY LEVELS. AS THE UPPER LOW LIFTS FURTHER NORTHEAST INTO THE MIDWEST THURSDAY NIGHT AND THE SURFACE LOW BECOMES VERTICALLY STACKED...A WEAK COLD FRONT/SURFACE TROUGH WILL MOVE THROUGH THE AREA HELPING TO BRING AN END TO THE RAIN AND THUNDERSTORM CHANCES. THE SURFACE TROUGH WILL WASH OUT EARLY FRIDAY WITH THE SOUTHEAST U.S. RIDGE AND SOUTHERLY FLOW BUILDING BACK OVER THE MID SOUTH ON FRIDAY. THIS WILL PROVIDE A RETURN TO DRY WEATHER BUT UNSEASONABLY WARM TEMPERATURES NEAR 70 DEGREES IN MOST AREAS. A STRONGER COLD FRONT SHOULD MOVE ACROSS THE MID SOUTH BY NEXT SATURDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE REGION. MUCH COLDER AIR SHOULD MOVE INTO THE REGION BEHIND THE FRONT FOR NEXT SUNDAY AS THE FLOW REMAINS SOUTHWESTERLY ALOFT. THIS COULD ALLOW FOR A FAVORABLE WINTER STORM PATTERN TO DEVELOP OVER THE REGION FOR THE END OF THE EXTENDED FORECAST PERIOD AND BEYOND. JLH && .AVIATION... 06Z TAF CYCLE VFR CONDITIONS WILL CONTINUE FOR THE ENTIRE FORECAST PERIOD. WINDS WILL BE LIGHT AND MAINLY FROM THE SOUTHEAST THROUGH THE ENTIRE FORECAST PERIOD. ARS && .PRELIMINARY POINT TEMPS/POPS... MEM 32 59 47 60 / 0 0 40 80 MKL 23 57 42 58 / 0 0 30 70 JBR 25 54 41 56 / 0 0 30 70 TUP 30 60 48 61 / 0 0 40 80 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$