433 FXUS61 KRLX 050537 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 137 AM EDT SUN AUG 5 2012 .SYNOPSIS... MUGGY AUGUST AIR THROUGH WEEKEND. WITH A LOCAL DOWNPOUR POSSIBLE. MORE WIDESPREAD AND ORGANIZED CONVECTION LIKELY SUNDAY...WELL AHEAD OF COLD FRONT. DRIER AIR TRIES TO CREEP SOUTH MONDAY. && .NEAR TERM /THROUGH TODAY/... 130 AM UPDATE...NO SIGNIFICANT CHANGES MADE TO ONGOING FORECAST. PREVIOUS DISCUSSION... CONVECTION CURRENTLY DEVELOPING IN ASSOCIATION WITH WEAK VORT MAX SHOWING UP ON RAP MOVING INTO CWA FROM THE WEST. DOWNPOURS WILL BE POSSIBLE WITH THESE STORMS...AND ISOLATED FLASH FLOODING MAY OCCUR. NOT EXPECTING FLASH FLOOD THREAT TO BE WIDESPREAD ENOUGH TO WARRANT A SHORT FLASH FLOOD WATCH THOUGH THIS EVENING. TOMORROW IS ANOTHER STORY...MOISTURE CONTINUES TO INCREASE OVERNIGHT...WITH PWAT VALUES CLIMBING TO OVER 2.25 INCHES BY 18Z SUNDAY ON THE NAM AND GFS. EXPECT WIDESPREAD PRECIPITATION...WITH VERY HEAVY RAINFALL SUNDAY AFTERNOON INTO SUNDAY NIGHT...AND OPTED TO ISSUE A FLASH FLOOD WATCH FOR LINE ROUGHLY HTS TO CKB AND SOUTH. ONE THING TO WATCH WILL BE STORM SPEEDS...WITH 20-30KTS MID LEVEL FLOW...STORMS WILL BE PROGRESSIVE...BUT WITH FLASH FLOOD GUIDANCE BETWEEN 1.5 AND 2 INCHES ACROSS A LOT OF THE WATCH AREA...EVEN STORMS THAT ARE MOVING COULD EASILY REACH THIS THRESHOLD. PLUS...IF ANY TRAINING CELLS OCCUR THREAT WILL INCREASE GREATLY. AS FOR SEVERE THREAT...MODELS HAVE BEEN BACKING OFF ON INSTABILITY A BIT. THINK THIS IS A GOOD TREND...DUE TO MORE CLOUDS LEADING TO LESS HEATING. STILL...1500-2000 J/KG CAPE SHOULD BE ENOUGH TO TAP INTO GOOD MID-LEVEL FLOW AND PRODUCE STRONG TO SEVERE WIND GUSTS IN THE TALLER STORMS. BLENDED IN MET GUIDANCE FOR TEMPS OVERNIGHT...AS IT HAS BEEN PERFORMING QUITE WELL LATELY...WHICH RESULTED IN MINIMAL CHANGES. WITH MORE CLOUDS AROUND...BLENDED IN THE MAV FOR HIGHS TOMORROW LIKING ITS DEPICTION OF COOLER TEMPS IN SE OHIO WHERE PRECIP WILL REACH FIRST. THIS RESULTED OVERALL IN A BIT COOLER DAY THAN PREVIOUS FORECAST. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... WE ARE HOPING THE PREFRONTAL CONVECTION DOES NOT ORIENT MORE EAST TO WEST...BUT THE FLASH FLOOD WATCH WAS POSTED EARLY...FOR THAT POSSIBILITY. AS WE HEAD INTO SUNDAY EVENING...OUR SOUTHERN COUNTIES SEEM TO BE MORE VULNERABLE TO SOME TRAINING...DESPITE THE 25 TO 30 KNOT CELL MOVEMENT THAT WE ARE EXPECTED. WILL BASE FORECAST ON SURFACE FRONT FROM NEAR EKN TO CRW TO SOUTH OF HTS AT 12Z MONDAY. SO HAD TO LEAVE SOME CHANCE POPS ALONG THAT FEATURE. PICTURING LOW CLOUDS ALONG THAT FRONT TOO. PROBABLY MOSTLY JUST LINGERING RAIN SHOWERS RATHER THAN THUNDER. PROBLEM THEN BECOMES...HOW LONG TO LINGER SOME 20/30 POPS IN OUR EXTREME SOUTH INTO TUESDAY. WE ARE TYPICALLY LEARY OF THE DRIER AIR IN THE LOW LEVELS MAKING IT THROUGH THE SOUTHERN MOUNTAINS. SO EVEN THOUGH THE MID LEVELS SHOULD DRY OUT...WILL NOW HOLD ONTO SOME 20/30 POPS IN SW VIRGINIA TO NEAR BECKLEY FOR TUESDAY. THERE COULD BE WIDESPREAD FOG MONDAY NIGHT FROM EKN TO CRW INTO THE COAL FIELDS. YET...BEING THE THIRD NIGHT INTO THE FUTURE...WILL HOLD OFF INCLUDING THOSE SPECIFICS FOR NOW. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... 12Z GFS AND 12Z ECMWF SOLUTIONS CONTINUE TO AGREE THAT THE MID LEVEL RIDGE...BAKING THE PLAINS THIS SUMMER...WILL SLIDE BACK WEST INTO THE GREAT BASIN...WITH A STRONG TROF SWINGING THROUGH OUR VICINITY ON DAY 7...WITH THE SURFACE FRONT LIKELY AHEAD OF IT...ON DAY 6/FRIDAY. PROBLEM FOR WEDNESDAY AND THURSDAY IS THE DEEP MOISTURE LINGERING TO OUR SOUTHEAST. WILL TRY TO HOLD WEDNESDAY DRY MAINLY FOR COUNTIES NORTH OF A HTS-CRW-EKN LINE...WITH SOME 20/30 POPS ALONG OUR SOUTHEASTERN COUNTIES WEDNESDAY. WENT ALONG WITH HPC MEDIUM RANGE CHANCE POPS FOR THURSDAY AND FRIDAY...WITH A COOL DOWN FOR SATURDAY. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... 06Z SUNDAY THRU 06Z MONDAY...GENERALLY VFR CEILINGS 5000-8000 FEET DEVELOPING OVERNIGHT MINIMAL FOG IF ANY DUE TO SOUTHERLY BREEZES BEING MAINTAINED. AFTER 12Z...COLD FRONT APPROACHES FROM THE WEST WITH INCREASING SHOWERS AND THUNDERSTORMS FROM WEST TO EAST ON SUNDAY. SOME STORMS MAY BE SEVERE. INTERMITTENT MVFR/IFR CONDITIONS WILL LIKELY RESULT IN STRONGER STORMS. OUTSIDE OF STORMS GENERALLY VFR CEILINGS 3500-4500 FEET BEFORE LOWERING AROUND 21Z. EXPECT GUSTY SOUTHWEST WINDS AHEAD OF THE FRONT ON SUNDAY. IFR CIGS WILL BE POSSIBLE MAINLY AT NORTHERN STIES AFTER 00Z MONDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND INTENSITY OF SHOWERS AND THUNDERSTORMS SUNDAY MAY VARY...AND WILL DEPEND OF AMOUNT OF CLOUDS AND HEATING. FLIGHT CONDITIONS MAY VARY MAINLY AFTER 18Z. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SUN 08/05/12 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY M M M H H H M H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 06Z MONDAY... IFR POSSIBLE IN LOW STRATUS NEAR SURFACE FRONT MONDAY MORNING...MAINLY AT SOUTHERN AND EASTERN SITES. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR WVZ005-006-013>020-024>040-046-047. OH...FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR OHZ087. KY...FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...KTB/MZ NEAR TERM...MZ/50 SHORT TERM...KTB/ARJ LONG TERM...KTB AVIATION...50