FXUS63 KJKL 041551
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1051 AM EST FRI DEC 4 2009

.SHORT TERM.../THE REST OF TODAY/...UPDATED

EVEN AS THE LOWER CLOUDS RAISE SLIGHTLY AND EVEN CLEAR PARTLY IN OUR
MOST WRN COUNTIES... A THICK SHIELD OF HIGH CLOUDS STREAM IN FROM THE
SW. SKIES WILL REMAIN MOSTLY CLOUDY FOR ALL BUT OUR BLUEGRASS
COUNTIES AND UPDATED FORECAST WILL SO NOTE. TEMPS BEGAN THE DAY
SLIGHTLY BELOW FORECAST LOWS BUT HAVE OUT PACED THE FORECAST RISE SO
THEY ARE NOW RUNNING A DEG OR TWO ABOVE EXPECTED VALUES. THICK CI AND
LOW SUN ANGLES WILL LIMIT THE SOLAR INSOLATION... BUT STILL EXPECT
HIGHS A DEG OR TWO ABOVE FCST MAX TEMPS. FORECAST UPDATE WILL FOCUS
ON CLOUD COVER AND MAX TEMPS. REST OF FCST OK.

THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...

/TODAY THROUGH SUNDAY/

THE MODELS ARE IN GOOD AGREEMENT WITH THE GENERAL PATTERN BUT THERE
ARE A FEW DIFFERENCES IN THE TIMING. THE WRAP AROUND MOISTURE FROM
THE LOW THAT MOVE ACROSS THE AREA EARLIER IS MOVING OUT OF THE AREA.
DURING THE DAY TODAY...THE LOW CLOUDS SHOULD BE BURNING OFF AS THE
MIDDLE CLOUDS FROM THE NEXT SYSTEM MOVE INTO THE AREA. THIS NEXT
SYSTEM IS A STRONG UPPER TROUGH THAT IS MOVING IN FROM THE WEST AND
WILL SORT OF ACT LIKE A WINTER CLIPPER SYSTEM. THIS SYSTEM SHOULD
BRING SOME SNOW TO EASTERN KENTUCKY AFTER LATE FRIDAY NIGHT THROUGH
SATURDAY MORNING. THERE IS A BIG DIFFERENCE ON HOW THE NAM AND THE
GFS ARE HANDLING THIS SYSTEM. WITH THE CONTINUED NW SURFACE FLOW...THERE
WILL BE NO WAY TO ADVECT IN ANY LOW LEVEL MOISTURE. SO FOR THIS
SYSTEM TO PRODUCE PRECIPITATION IT WILL HAVE TO START WILL HAVE TO
BUILD IN DOWN FROM THE MID LAYERS. LOOKING AT THE TIME HEIGHT OF THE
GFS AND THE NAM...THE NAM IS SHOWING WAY TOO MUCH MOISTURE IN THE
LOWER LEVELS AND THE NAM IS ABOUT 6 HOURS SLOWER THAN THE GFS. I HAVE
CHOSEN TO GO MORE WITH THE GFS TIMING...WHICH IS FROM 4AM TO 7AM WITH
THE SNOW...BUT HAVE EXTENDED THE SNOW INTO THE MORNING HOURS AS A
COMPROMISE. CONSIDERING THE GROUND TEMPERATURES...THE SNOW WILL BE
MOSTLY ON GRASSY SURFACES AND AT UPPER ELEVATIONS...BUT MUCH OF
EASTERN KENTUCKY WILL SEE A SKIFF OF SNOW WITH UP TO ONE INCH ON
PLACES LIKE BLACK MOUNTAIN. THIS SYSTEM SHOULD MOVE RAPIDLY THROUGH
THE AREA AND WE SHOULD SEE SOME QUICK CLEARING BEHIND THE SYSTEM AND
THEN WILL HAVE A DRY PERIOD AS HIGH PRESSURE BUILDS INTO THE AREA. FOR
TEMPS...FOR FRIDAY...WENT BELOW THE COOLEST MOS BECAUSE THE MODELS
DID NOT HAVE ENOUGH CLOUD COVER. FOR THE REST OF THE PERIOD WENT WITH
THE COOLEST MOS.

.LONG TERM.../SUNDAY NIGHT THROUGH THURSDAY/

PROGRESSIVE PATTERN WILL CONTINUE THROUGH THE LONG TERM PERIOD WITH 
TWO SYSTEMS TO DEAL WITH. OVERALL...PROGS REMAIN IN RELATIVELY GOOD 
AGREEMENT SO CONFIDENCE CONTINUES TO BUILD...ESPECIALLY REGARDING A 
RATHER HEALTHY SYSTEM LIKELY TO AFFECT THE EASTERN U.S. DURING THE 
MIDDLE OF NEXT WEEK. WHILE THERE WILL NO DOUBT BE CHILLY 
SPELLS...THERE SEEMS TO BE NO MAJOR ARCTIC OUTBREAK ON THE HORIZON 
FOR OUR AREA AS FAST ZONAL FLOW PATTERN FLOODS THE CONUS WITH 
PACIFIC AIR WHILE KEEPING THE ARCTIC AIR MASS LOCKED WELL TO OUR 
NORTH.

A DRY AIR MASS WILL BE A HINDRANCE TO A WEAK FRONTAL BOUNDARY WHICH 
IS PROGGED TO PASS THROUGH THE AREA ON MONDAY AND WE WILL ONLY OFFER 
A SLIGHT CHANCE OF A SHOWER WITH THIS SYSTEM. WILL HAVE TO WATCH THE 
TIMING OF THE SYSTEM THOUGH AS IT COULD BRING A BIT OF FREEZING RAIN 
EARLY MONDAY MORNING IF THE FRONT IS A FEW HOURS QUICKER AND ANY 
PRECIP ACTUALLY FALLS FROM IT.

WEAK HIGH PRESSURE WILL BUILD INTO THE REGION LATE MONDAY NIGHT INTO 
EARLY TUESDAY...BUT THE NEXT STORM SYSTEM ORGANIZING TO OUR 
SOUTHWEST WILL THEN BRING INCREASING RAIN CHANCES LATE ON TUESDAY 
INTO WEDNESDAY. WHILE CONFIDENCE IS INCREASING WITH THIS 
SYSTEM...THERE WILL NO DOUBT BE SOME CHANGES WITH THE TIMING AS THE 
EVENT NEARS SO ONLY INCREASED POPS TO AROUND 50 PERCENT TUESDAY 
NIGHT AND WEDNESDAY FOR NOW. COLDER AIR WILL THEN WRAP AROUND THE 
SYSTEM WEDNESDAY NIGHT SO A CHANGEOVER TO A FEW SNOW SHOWERS IS 
POSSIBLE BEFORE THE PRECIP ENDS. DRIER AND COOLER THEN FOR THURSDAY.

&&

.AVIATION.../12Z TO 12Z/

VFR CIGS NOW PREDOMINATE ACROSS EASTERN KENTUCKY. THE IR SATELLITE IS
SHOWING A MID DECK STARTING TO MOVE INTO THE AREA. EXPECT IT TO STAY
CLOUDY TODAY...BUT THE CIGS SHOULD STAY ABOVE 3000 FEET. AN UPPER
TROUGH MOVES THROUGH THE AREA DURING THE EARLY MORNING HOURS AND WILL
BRING WIDESPREAD SNOW ACROSS MOST OF EASTERN KENTUCKY. EXPECT ALL BUT
THE BLUEGRASS TO GET A SKIFF OF SNOW...WITH ELEVATIONS ABOVE 2500
FEET SEEING UP TO ONE INCH. THE PAVEMENT TEMPERATURES SHOULD BE
PRETTY WARM...SO DO NOT EXPECT THE RUNWAYS TO BE EFFECTED. EXPECT
MOSTLY MVFR CONDITIONS WITH TEMPO IFR DURING THE HEAVIEST SNOWFALL.

&&

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

&&

$$

SHORT TERM...JJ/DUSTY
LONG TERM....SCHOETTMER
AVIATION...JJ