920 FXUS64 KHUN 140859 AFDHUN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HUNTSVILLE AL 359 AM CDT THU MAR 14 2013 .DISCUSSION... ANOTHER CHILLY NIGHT FOR MID MARCH CONTINUED ACROSS THE REGION. MUSCLE SHOALS WAS THE ONLY LOCATION IN OUR LOCAL WEATHER ROUNDUP ABOVE FREEZING AT 35F AS OF 3 AM. OTHER SPOTS WERE COLDER...WITH READINGS IN THE UPPER 20S TO MID 30S...WITH LIGHT WINDS AND CLEAR SKIES. DEWPOINT VALUES WERE GENERALLY A GOOD 5-10 DEGREES COOLER THAN THE ACTUAL AIR TEMPERATURES...WHICH SHOULD KEEP FOG DEVELOPMENT UNLIKELY. COLD HIGH PRESSURE CENTERED OVER THE MID SOUTH AND TENNESSEE VALLEY WAS THE MAIN FACTOR CONTROLLING THE LOCAL WEATHER. IT WAS UNDER A BROAD TROUGH EXTENDING SOUTHWARD FROM A SEEMINGLY PERMANENT AREA OF LOW PRESSURE OVER NORTHERN CANADA...WITH A MAJOR LOW PRESSURE LOBE SWEEPING WEST-EAST ACROSS QUEBEC. A FURTHER OUT VIEW REVEALED SORT OF A SPLIT FLOW PATTERN...WITH A STREAM OF SUBTROPICAL MOISTURE ENTERING THE PICTURE FROM SOUTH OF THE BAJA TO SOUTHERN FLORIDA. HIGH TEMPERATURES YESTERDAY IN THE LOWER 50S ACROSS THE REGION WERE A GOOD 10 DEGREES OR SO BELOW SEASONABLE NORMS. THE ABOVE MENTIONED SURFACE HIGH SHOULD BUILD FURTHER TO THE SOUTH TODAY...BRINGING A WEAK SOUTHERLY FLOW AND SOME MODERATION WITH HIGH TEMPS. THEY SHOULD RISE INTO THE MID/UPPER 50S...STILL ON THE COOL SUDE BUT WARMER THAN YESTERDAY. CLOUDS WILL ALSO INCREASE AS A WEAK UPPER LEVEL DISTURBANCE NEARS FROM THE NW. THIS IMPULSE WILL BRING A SLIGHT CHANCE OF RAIN TO SOUTHERN MIDDLE TENNESSEE AND ADJACENT NE ALABAMA THIS AFTERNOON AND EVENING. THE ECMWF...THE ONLY MODEL BEFOREHAND THAT WAS PAINTING LIGHT RAINS OVER THE REGION WAS JOINED BY THE SREF THIS MORNING. THE GFS WAS SHOWING PRECIP TOO...BUT IT WAS DISPLACED JUST TO THE NE OF OUR FORECAST AREA. HAVE KEPT A MENTION OF SHOWERS IN...BUT DISPLACED RAIN CHANCES FURTHER TO THE NE. THOSE SHOWERS SHOULD BE EAST OF THE REGION BY THE LATE EVENING...WITH CLOUDS DECREASING OVERNIGHT. A RETURN OF ABOVE SEASONAL WARMTH IS IN THE CARDS FRIDAY...AS A STRONGER SW FLOW AND MORE SUN HELP PUSH HIGHS INTO THE MID 60S TO AROUND 70. SOMEWHAT WARMER TEMPERATURES FROM THE UPPER 60S AND LOWER 70S ARE EXPECTED SATURDAY. ALONG WITH THE WARMTH...RELATIVE HUMIDITY VALUES WILL INCREASE AS THE SOUTHERLY FLOW BRINGS SOME MOISTURE FURTHER INLAND FROM A WORKED OVER GULF. THIS MOISTURE AND THE APPROACH OF A COLD FRONT WILL BRING A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS BEGINNING SATURDAY AFTERNOON ACROSS OUR SOUTHERN MIDDLE TENNESSEE COUNTIES. BOTH THE GFS AND ECMWF KEEP THE FRONTAL BOUNDARY STALLED IN A WEST TO EAST FASHION ACROSS SOUTH/CENTRAL TENNESSEE. THE GFS WAS SLIGHTLY MORE AGGRESSIVE BRINGING THE FRONT NEAR THE TN/AL BORDER FROM LATE SATURDAY THROUGH SUNDAY...WITH THE ECMWF FURTHER NORTHWARD WITH THE FRONT. GIVEN THOSE DIFFERENCES...HAVE KEPT ONLY LOWER END RAIN CHANCES FOR SUNDAY. SOMEWHAT BETTER RAIN CHANCES ARE EXPECTED LATE SUNDAY INTO MONDAY. GFS DERIVED BUFR SOUNDINGS WERE SHOWING THE BEST INSTABILITY/SHEAR DURING MONDAY AND BETTER CHANCES FOR CONVECTION...AS A COLD FRONT SWEEPS ACROSS THE REGION FROM NW-SE. THE FRONTAL PASSAGE WILL END THE RAIN CHANCES LATE MONDAY AND TUESDAY...BUT BRING COLDER AIR BACK ACROSS THE REGION. EVEN THOUGH ASTRONOMICAL SPRING BEGINS AROUND 602 AM CDT NEXT WEDNESDAY MORNING...LOW TEMPERATURES NEAR FREEZING CANNOT BE RULED OUT. A SLIGHT WARMUP WITH HIGHS AROUND 60...STILL BELOW SEASONABLE NORMS... IS FORECAST NEXT WEDNESDAY. RSB && .AVIATION... /ISSUED 1214 AM CDT THU MAR 14 2013/ FOR 06Z TAFS...VFR CONDITIONS ARE EXPECTED TO CONTINUE ACROSS N AL/S MIDDLE TN FOR THE NEXT 24 HOURS. SL.77 && .PRELIMINARY POINT TEMPS/POPS... HUNTSVILLE 56 40 72 51 / 10 10 0 0 SHOALS 58 40 73 51 / 10 10 0 0 VINEMONT 54 39 71 49 / 10 0 0 0 FAYETTEVILLE 53 39 71 50 / 20 10 0 0 ALBERTVILLE 50 36 66 46 / 10 10 0 0 FORT PAYNE 53 34 70 45 / 10 10 0 0 && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WEATHER.GOV/HUNTSVILLE.