454 FXUS64 KHUN 260218 AAB AFDHUN AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE HUNTSVILLE AL 918 PM CDT THU APR 25 2013 .UPDATE... EVENING UPDATE. && .DISCUSSION... TEMPERATURES ACROSS THE TENNESSEE VALLEY THIS EVENING RANGE FROM THE UPPER 40S TO THE LOWER 50S, WITH HUNTSVILLE INTERNATIONAL AIRPORT REPORTING 58F AT THIS HOUR. SFC HIGH PRESSURE REMAINS ANCHORED JUST NORTH OF THE CWA, WITH LIGHT WINDS IN PLACE ACROSS THE REGION. ALTHOUGH A FEW HIGH CLOUDS WILL TRY TO SNEAK INTO THE AREA FROM THE WEST BY MORNING, GIVEN THE IDEAL RADIATIONAL COOLING SETUP FOR TONIGHT, WILL LEAVE THE MENTION FOR PATCHY FROST IN THE SHELTERED VALLEY LOCATIONS OF NERN AL AND SRN MIDDLE TN. MORNING LOWS IN THESE LOCATIONS WILL BOTTOM OUT IN THE MIDDLE TO UPPER 30S (WITH LOWER 40S EXPECTED ELSEWHERE). AS FAR AS CHANGES FOR TONIGHT, HAVE ONLY MADE MINOR ADJUSTMENTS TO HOURLY TEMPS TO ACCOUNT FOR THE LATEST OBS. OTHERWISE, THE FORECAST IS IN GREAT SHAPE AND NO OTHER CHANGES ARE NECESSARY. WILL FRESHEN WORDING IN THE ZONES AND RESEND THEM SHORTLY. 12 && .AVIATION... /ISSUED 629 PM CDT THU APR 25 2013/ FOR 00Z TAFS... VFR CONDS ARE EXPECTED THRU THE TAF PERIOD AS HIGH CLOUDS ~25KFT GRADUALLY INCREASE THRU 27/00Z. 12 && .PREV DISCUSSION... /ISSUED 335 PM CDT THU APR 25 2013/ QUIET AND TRANQUIL WX CONDITIONS PREVAIL ACROSS THE CNTRL TN VALLEY THIS THU AFTERNOON...WITH A STRONG AREA OF HIGH PRESSURE LAYERED ACROSS THE MID TN AREA. AFTERNOON TEMPS HAVE TRENDED PREDOM IN THE SEASONAL MID 60S RANGE UNDER MOSTLY SUNNY SKIES. UNFORTUNATELY THE QUIET WX IS NOT XPCTED TO LAST HEADING INTO THE WEEKEND PERIOD. IN THE SHORT TERM THOUGH...ANOTHER QUIET AND UNSEASONABLY COOL NIGHT IS XPCTED ACROSS THE AREA AS THE SFC HIGH GRADUALLY SHIFTS NEWD INTO THE OH VALLEY REGION. IN FACT...LIGHT WINDS COUPLED WITH OVERNIGHT LOWS FALLING INTO THE UPPER 30S MAY YIELD SOME PATCHY FROST IN THE SHELTERED AREAS OF NE AL/SRN MID TN EARLY FRI MORNING. CONDITIONS SHOULD THEN BEGIN TO QUICKLY REBOUND/WARM AS SELY FLOW DEVELOPS ACROSS THE REGION WITH THE DEPARTING HIGH PRESSURE TO THE NE. THE FOCUS THEN SHIFTS TOWARD THE FIRST HALF OF THE WEEKEND PERIOD AS A DEVELOPING STORM SYSTEM OUT OF THE MID PLAINS BEGINS TO TRANSLATE EWD. THE ASSOCIATED SFC LOW AND ATTENDANT COLD FRONT LOOK TO MOVE INTO THE LOWER MS/MID SOUTH REGION DURING THE DAY SAT...WITH PRECIP GRADUALLY INCREASING ALONG/WELL AHEAD OF THE SYSTEM. PRECIP LOOKS TO START OFF AS LIGHT SHOWERS FRI EVENING...WITH RAINFALL GRADUALLY OVERSPREADING THE AREA FROM W TO E DURING THE OVERNIGHT HRS. ISO/SCT EMBEDDED TSTMS SHOULD THEN BEGIN TO DEVELOP HEADING INTO THE MORNING HRS SAT...AS UPPER WAVES START TO TRAVERSE EWD AHEAD OF THE ONCOMING STORM SYSTEM. IT IS SOMEWHAT DIFFICULT AT THIS POINT TO DETERMINE THE EXACT PLACEMENT/TIMING OF ANY HEAVIER RAINFALL/STRONGER TSTMS. MUCH OF THIS MAY DEPEND ON THE EXTENT OF WAA NWD AHEAD OF THE SFC LOW SAT...WHICH UNFORTUNATELY VARIES BETWEEN THE LATEST MODEL RUNS. IN ANY CASE...WIDESPREAD SHOWERS COUPLED WITH EMBEDDED TSTMS LOOK TO DOMINATE THE LOCAL WX PATTERN SAT/SAT NIGHT...AS THE WX SYSTEM MAKES ITS WAY EWD. RAINFALL HOPEFULLY WILL BEGIN TO TAPER OFF FROM THE W DURING THE DAY SUN AS THE SFC LOW/ASSOCIATED FRONTAL BOUNDARIES CLR THE FORECAST AREA TO THE E. QUIET AND NEAR SEASONAL LIKE WX IS THEN XPCTED FOR THE START OF THE NEW WORK WEEK...AS WEAK HIGH PRESSURE QUICKLY MOVES EWD ACROSS THE SE REGION. GENERALLY UNSETTLED WX LOOKS TO THEN DEVELOP AROUND MID WEEK...AS THE MOISTURE FLOW INCREASES ACROSS THE AREA COUPLED WITH PERHAPS WEAK PASSING UPPER DISTURBANCES. 09 && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WEATHER.GOV/HUNTSVILLE.