703 
FXUS63 KJKL 190820 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
420 AM EDT TUE MAR 19 2013

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 334 AM EDT TUE MAR 19 2013

CONDITIONS ACROSS EASTERN KENTUCKY FEATURE LEFTOVER CLOUD COVER 
FINALLY EXITING EASTERN KENTUCKY. A FEW AREAS OF SPOTTY DRIZZLE MAY 
BE PRESENT IN THE EAST BUT THAT WILL EVENTUALLY DRY OUT. BEHIND THE 
FRONT...NORTHWEST WINDS WILL GUST UP TO 20 KNOTS IN SOME LOCATIONS 
BEFORE THE INVERSION SETS UP BRIEFLY. INVERSION BREAK WILL OCCUR 
TODAY BY 15Z WITH WINDS CONTINUING TO GUST TO 20 KNOTS TODAY. A 
COOLER AIR MASS IN PLACE TODAY WILL TEMPER HIGHS INTO THE UPPER 40S 
TO AROUND 50. 

MEANWHILE...A PROGRESSIVE PATTERN WILL BE IN PLACE IN NORTHWEST FLOW 
OVER THE OHIO VALLEY. A FAST MOVING WEAK WAVE WILL BEGIN TO 
TRACK INTO THE OHIO VALLEY AS SOME CIRRUS WILL OVERSPREAD THE AREA 
BY THIS EVENING. THIS CLOUD COVER WILL HINDER THE RIDGE VALLEY SPLIT 
TONIGHT WITH VALLEYS DROPPING INTO THE MID 20S AND RIDGES HOVERING 
AROUND 30 FOR LOWS TONIGHT KEEPING THE SPLIT AT ABOUT 5 DEGREES. 
HEADING INTO WEDNESDAY...MODEL PROFILES INDICATE A DRY AIR MASS IN 
PLACE BUT...THERE WILL BE SOME INSTABILITY IN PLACE BY THE 
AFTERNOON. THIS IN ADDITION WITH WEAK FORCING AND ASSISTANCE FROM 
OROGRAPHICS WILL BE ENOUGH FOR THE DEVELOPMENT OF SOME AFTERNOON 
SHOWERS OVER THE AREA. GIVEN THE DRY AIR MASS...HAVE DECIDED TO KEEP 
SLIGHT CHANCE POPS FOR WEDNESDAY AFTERNOON. GIVEN THE CONVECTIVE 
PROFILE...HAVE LOWER TEMPS FOR SNOWFALL BUT EVEN THEN...SURFACE 
TEMPS LOOK TO BE A BIT TOO WARM. TEMPS ON BLACK MOUNTAIN LOOK TO BE 
JUST COLD ENOUGH FOR SOME SNOWFALL BUT WITH NO ACCUMULATION 
EXPECTED. WITH THE PROGRESSIVE PATTERN...THE FRONT WILL EXIT THE AREA 
BY WEDNESDAY EVENING...ALSO SPEAKING OF SOME HIGHER WIND 
SPEEDS...WINDS WILL BE GUSTY AGAIN FOR WEDNESDAY WITH 20 KNOT WINDS 
MIXING TO THE SURFACE BY WEDNESDAY AFTERNOON. 

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 420 AM EDT TUE MAR 19 2013

THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE FIRST PART OF THE
EXTENDED BEFORE DIVERGING OVER THE WEEKEND AND INTO THE START OF NEXT
WEEK. THEY AGREE THAT A DEEP TROUGH WILL PIVOT OUT OF THE OHIO VALLEY
TO END THE WORK WEEK...BUT NOT BEFORE ONE LAST BATCH OF ENERGY
SHOOTS THROUGH EAST KENTUCKY WEDNESDAY NIGHT INTO THURSDAY. IN THE
WAKE OF THIS...HEIGHTS WILL GRADUALLY RISE THROUGH SATURDAY BEFORE
ATTENTION TURNS TO A VEXING TROUGH MOVES OUT OF THE ROCKIES AND INTO
THE PLAINS. THIS SYSTEM HAS SHOWN WIDE VARIABILITY WITH ITS PROGRESS
EAST IN THE VARIOUS MODELS AND RUNS. ACCORDINGLY...CONFIDENCE REMAINS
LOW IN ANY SPECIFIC SOLUTION...THOUGH THE MOST RECENT SET OF
MODELS...INCLUDING THE 00Z ECMWF...IS SHOWING A DISTINCT SHIFT
TOWARD A CONSENSUS. THIS CONSENSUS IS IN LINE WITH THE LATEST
THOUGHTS FROM WPC AND THE ENSEMBLES OF BOTH THE GFS AND ECMWF. THE
TROUGH APPEARS TO BE DESTINED TO WRAP UP INTO A LOW THAT WILL CROSS
THE TENNESSEE AND OHIO VALLEYS LATER IN THE WEEKEND AND THROUGH THE
APPALACHIANS ON MONDAY. THE LATEST ECMWF IS STILL A NOTCH FASTER THAN
THE GFS HERE...BUT MUCH CLOSER THAN THE 12Z RUNS. WHILE THIS LEADS TO
A BETTER BLEND RESULT...ENOUGH DIFFERENCES REMAIN IN THE DETAILS OF
EACH MODEL TO MAKE FOR A LOW CONFIDENCE FORECAST WHEN IT COMES TO ANY
WX SPECIFICS...PARTICULARLY FOR DAYS 6 AND 7.

AN UNSEASONABLY COLD AIR MASS WILL REMAIN OVER EAST KENTUCKY UNTIL AT
LEAST FRIDAY MORNING AS ARCTIC HIGH PRESSURE MOVES THROUGH THE AREA.
EARLY IN THE PERIOD...UPPER LEVEL SUPPORT AND LINGERING LOW LEVEL
MOISTURE MAY BE ENOUGH TO KICK OFF NORTHWEST FLOW/UPSLOPE SNOW
SHOWERS OVER THE HIGHER TERRAIN OF EAST KENTUCKY WEDNESDAY NIGHT INTO
THE FIRST PART OF THURSDAY. DRIER WEATHER FOLLOWS INTO FRIDAY BEFORE
THE DEVELOPING SFC REFLECTION TO THE WEST STARTS TO SEND MOISTURE
INTO OUR SOUTHWEST COUNTIES....SPREADING NORTHEAST WITH TIME. EXPECT
THE CLOUDS TO MOVE OVER EAST KENTUCKY FAIRLY EASY...BUT THE PCPN MAY
BE MOSTLY SUPPRESSED TO THE SOUTH THROUGH SATURDAY. ANYTHING THAT
DOES MANAGE TO SEEP NORTH WILL LIKELY BE MIX OF RAIN AND SNOW AS
WARMER AIR WORKS IN AHEAD OF THE LOW...BUT THE COLD AIR LINGERS...
PARTICULARLY OVER OUR NORTHEAST COUNTIES. FOR SUNDAY...ALL DEPENDS ON
HOW THE SFC LOW AND ITS UPPER SUPPORT COME EAST. A NORTH TRACK...AS
DEPICTED IN THE ECMWF...WOULD MEAN MORE OF A RAIN THREAT THAN
SNOW... BUT A FURTHER SOUTH ONE...AS IMPLIED BY THE ENSEMBLES...WOULD
MORE LIKELY BE A SNOW MAKER...IF ANYTHING. THE FORECAST FOR THE
LATTER PART OF THE EXTENDED REPRESENTS A SPLITTING OF THESE
DIFFERENCES...BUT NOT NECESSARILY THE MOST LIKELY OUTCOME. MONDAY
WILL PROBABLY BE COLDER THAN SUNDAY AS THE LOW HEADS EAST IN THE
CONSENSUS SCENARIO...ALLOWING FOR A CONTINUED CHANCE OF SNOW...ALONG
WITH THE POTENTIAL FOR A DEEPER AND LARGER STORM THAN INDICATED BY
ANY MODEL BLEND. STAY TUNED.

THE CR MODEL BLEND CAME IN REASONABLE GIVEN THE MODELS IT USED...BUT
WITH THE NEW ECMWF COMING IN JUST AFTER 3 AM...AND WITH A BETTER JOG
TOWARD CONSENSUS...DID MAKE SOME MINOR ADJUSTMENT TO POPS FOR THE
LATTER PART OF THE FORECAST WITH THAT LATEST RUN IN MIND. ALSO MADE
SOME TWEAKS TO OVERNIGHT LOWS FOR TERRAIN EFFECTS FROM WEDNESDAY
NIGHT THROUGH FRIDAY NIGHT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 123 AM EDT TUE MAR 19 2013

ONLY ISSUE IN THE NEAR TERM FOR THE TAFS IS SOME LOW LEVEL DECKS
BEHIND THE FRONT. CURRENT TRENDS HOWEVER HAVE THE LOWER LAYERS
FINALLY EXITING THE AREA AFTER 09Z. THE ONLY OTHER ISSUE FOR THE TAFS
WILL BE STRONG NORTHWEST WINDS MIXING TO THE SURFACE AND GUSTING TO
20 KNOTS IN SOME LOCATIONS. WINDS SHOULD DIMINISH BY 23Z THIS
EVENING. 

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...SHALLENBERGER
LONG TERM...GREIF
AVIATION...SHALLENBERGER