-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KJKL 051217 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
717 AM EST THU DEC 5 2013

.UPDATE...
-- Changed Discussion --
ISSUED AT 717 AM EST THU DEC 5 2013

THE COLD FRONT CONTINUES TO MARCH EAST...NOW ALIGNED FROM WESTERN
OHIO DOWN THROUGH WESTERN KENTUCKY. PRECIPITATION HAS BLOSSOMED ALONG
AND OUT AHEAD OF THE SURFACE BOUNDARY...WITH LOCATIONS NORTH OF THE
I-64 CORRIDOR ALREADY SEEING SOME SCATTERED TO NUMEROUS SHOWER
ACTIVITY. THERE HAVE ALSO BEEN SOME EMBEDDED THUNDERSTORMS WITHIN THE
BAND. HAVE FRESHENED UP THE POP GRIDS TO ALIGN BETTER WITH CURRENT
RADAR TRENDS. HAVE ALSO UPDATED THE HOURLY TEMPERATURES AND DEW
POINTS...AS THERE ARE STILL A FEW STRAGGLING VALLEYS...STILL
REPORTING AROUND THE 50 DEGREE MARK...THAT REFUSE TO MIX OUT.
-- End Changed Discussion --

&&

.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 359 AM EST THU DEC 5 2013

VERY DYNAMIC WEATHER IS ON THE WAY AS MULTIPLE IMPACTS WILL AFFECT
THE COMMONWEALTH THROUGH THE SHORT TERM AND BEYOND.

A DEEP AREA OF SURFACE LOW PRESSURE IS CURRENTLY SITUATED ACROSS
LAKE SUPERIOR. THE ASSOCIATED COLD FRONT IS ALIGNED SOUTH ACROSS THE
OH/IN BORDER AND THEN ARCS BACK TO THE SOUTHWEST ACROSS THE OHIO
RIVER AND THEN ALONG THE MISSISSIPPI RIVER. A BAND OF CONVECTION HAS
FIRED UP ALONG THE OHIO RIVER FROM NORTH CENTRAL KENTUCKY DOWN
THROUGH WESTERN KENTUCKY IN THE PAST COUPLE OF HOURS OUT AHEAD OF THE
BOUNDARY AS IT MAKES ITS EASTWARD PUSH. MEANWHILE...EASTERN KENTUCKY
REMAINS IN THE WARM SECTOR...WITH TEMPERATURES MORE SUMMER-LIKE FOR
THE OVERNIGHT HOURS COMPARED TO NORMAL VALUES FOR EARLY DECEMBER.

THE MODELS ARE IN GOOD AGREEMENT WITH THE PROGRESSION OF THE FRONTAL
BOUNDARY THROUGH LATE THIS EVENING...CLEARING EASTERN KENTUCKY BY
DUSK AND THEN SETTLING ACROSS THE SOUTHERN APPALACHIANS WHERE IT WILL
STALL THROUGH FRIDAY BEFORE MAKING A MORE DECISIVE PUSH SOUTHEAST
INTO THE CAROLINAS BY LATE FRIDAY NIGHT.

SHOWERS WILL GRADUALLY MOVE IN FROM THE WEST THROUGH THE DAY TODAY.
POPS HAVE GENERALLY BEEN TRENDING A BIT SLOWER FOR THIS EVENT...SO
WILL ONLY CARRY ISOLATED TO SCATTERED POPS IN THE EAST THROUGH THE
MORNING...UNTIL THE FRONT DRAWS CLOSER. THERE WILL BE SOME
INSTABILITY AVAILABLE TODAY AND GIVEN THAT THERE HAS ALREADY BEEN AT
LEAST SOME IN CLOUD LIGHTNING ACTIVITY OUT WEST ALREADY...WILL
INCLUDE SOME SLIGHT CHANCES FOR THUNDER. GIVEN THE STRONGER WIND
PROFILE IN THE LOW LEVELS...IT IS NOT TOTALLY OUT OF THE QUESTION
THAT SOME GUSTY WINDS IN THE 30 TO 40 MILE PER HOUR RANGE COULD MIX
DOWN.

HIGHS TODAY WILL LIKELY BE ESTABLISHED IN THE EARLY PART OF THE DAY
ACROSS THE NORTHWEST PORTION OF THE AREA...BEFORE THE COLD FRONT
COMES THROUGH AND BRINGS MUCH COOLER AIR BEHIND IT. EXPECT STEADY
RAINS TO PICK UP TONIGHT...POSSIBLY FALLING HEAVY AT TIMES...AS WAVES
OF LOW PRESSURE RIDE UP ALONG THE SURFACE BOUNDARY.

ON FRIDAY...BOTH THE NAM AND GFS ARE INDICATING THE OVERALL BEST LIFT
TO PASS THROUGH FRIDAY AFTERNOON AS SOME 850-700 MB FRONTOGENETIC
FORCING RAMPS UP ACROSS THE AREA AS A BETTER EMBEDDED SHORT WAVE
PASSES BY OVERHEAD. THIS WILL BRING ANOTHER THREAT OF THUNDER
POTENTIALLY AND WILL MAINTAIN SLIGHT CHANCES THERE. THE BEST 12 HOUR
QPF WILL ALSO LIKELY OCCUR ON FRIDAY...WITH 1 TO 1.5 INCHES
POSSIBLE...SO ISOLATED FLOODING OF LOW LYING AREAS AND SIGNIFICANT
RISES ON RIVERS STILL LOOKS ON TARGET. TOTAL RAINFALL FOR THIS BATCH
OF RAINFALL REMAINS IN THE 2 TO 3 INCH RANGE...WITH A BIT OF A
LIGHTER TREND OVERALL IN THE PAST COUPLE OF DAYS.

FINALLY...AS DEEPER MOISTURE BEGINS TO PULL AWAY LATE FRIDAY
AFTERNOON INTO FRIDAY EVENING...ENOUGH COLDER AIR WILL GRADUALLY
UNDERCUT THE WARM NOSE ALOFT AND ALLOW FOR A SNOW...SLEET...AND
PERHAPS FREEZING RAIN/ DRIZZLE THREAT. IMPACTS FROM THIS LOOK TO BE
ADVISORY CRITERIA AT WORST AS THE GROUND WILL BE VERY WARM AND DEEPER
MOISTURE CUTS OFF QUICKLY. THERE WILL LIKELY BE A SHARP CUTOFF WHERE
THE WINTRY MIX FALLS AND CREATES SOME TEMPORARY SLICK
CONDITIONS...MOST LIKELY NORTHWEST OF A LINE FROM SANDY HOOK TO
STANTON. ANOTHER POTENTIAL ISSUE WILL BE SOME REFREEZING THAT TAKES
PLACE OVERNIGHT FRIDAY NIGHT AS ARCTIC AIR INVADES FROM THE
NORTHWEST. OVERNIGHT LOWS WILL RANGE FROM THE LOW TO MID 20S
NORTHWEST...TO AROUND 30 IN THE SOUTHEAST.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 452 AM EST THU DEC 5 2013

VERY COMPLICATED WEATHER PATTERN THROUGH THE FIRST SEVERAL DAYS OF
THE EXTENDED FORECAST. FAIRLY GOOD AGREEMENT EXISTED BETWEEN THE GFS
AND ECMWF MODELS FOR THIS TIME FRAME...BELIEVE IT OR NOT. THE
OVERALL WEATHER PATTERN TO START THE EXTENDED IS PROGGED TO FEATURE
COLD AND MOIST NORTH TO NORTHWEST FLOW BEHIND A DEPARTING FRONTAL
BOUNDARY. BASED ON THE LATEST FORECAST SOUNDINGS AND TIME HEIGHT
CROSS SECTIONS...THERE WILL EXIST THE POSSIBILITY OF FREEZING
DRIZZLE THROUGH LATE SATURDAY MORNING. THIS PRECIPITATION WILL TAPER
OFF QUICKLY TO DRIZZLE BY EARLY AFTERNOON...WITH THE REST OF THE
AFTERNOON AND EARLY EVENING FREE OF PRECIPITATION. THIS WILL CHANGE
QUICKLY...HOWEVER...AS ANOTHER STORM SYSTEM MOVES IN FROM THE SOUTH.
THIS SECOND WEATHER SYSTEM IS FORECAST TO MATERIALIZE OVER THE
WESTERN GULF OF MEXICO SATURDAY AND SATURDAY NIGHT. AN AREA OF LOW
PRESSURE IS EXPECTED TO FORM OVER SOUTHERN TEXAS...ALONG THE WESTERN
OF EDGE OF THE PREVIOUSLY STALLED FRONTAL BOUNDARY. ONCE THIS AREA
OF LOW PRESSURE BECOMES BETTER DEFINED SATURDAY NIGHT...IT WILL GET
CAUGHT UP IN THE SOUTHERN BRANCH OF THE JET STREAM...AND CARRIED
NORTHEASTWARD ACROSS THE TENNESSEE AND OHIO VALLEY REGIONS. WITH
COLD AIR ALREADY IN PLACE AT THE SURFACE...A WINTRY MIX OF
PRECIPITATION WILL QUICKLY FORM NORTH OF THE APPROACHING LOW LATE
SATURDAY NIGHT THROUGH THE MORNING IN ON SUNDAY. THE PRECIPITATION
WILL LIKELY BEGIN AS ALL SNOW FOR A BRIEF PERIOD...BEFORE
TRANSITIONING TO A MIX OF FREEZING RAIN...SLEET...AND SNOW AS MOIST
AIR OVERRUNS THE COLD SURFACE AIR MASS. SOME LIGHT ICE ACCUMULATIONS
WILL BE POSSIBLE EARLY IN THE DAY...BUT WARMING TEMPERATURES AND
RAIN SHOULD MELT MOST OR ALL OF THIS OF LATER IN THE DAY. THE
SURFACE TEMPERATURES WILL GRADUALLY WARM UP DURING THE DAY ON
SUNDAY...WITH PRECIPITATION GRADUALLY CHANGING BACK OVER TO RAIN FROM
SOUTH TO NORTH BY SUNDAY AFTERNOON.

TEMPERATURES SHOULD REMAIN WARM ENOUGH FOR PRECIPITATION TO REMAIN
IN LIQUID FORM SUNDAY NIGHT AND MONDAY. ANOTHER SHOT OF COLD AIR IS
THEN EXPECTED TO FILTER SOUTH MONDAY AND TUESDAY...AS WINDS SHIFT TO
THE WEST AND NORTHWEST BEHIND THE DEPARTING WEATHER SYSTEM. SOME
LIGHT SNOW ACCUMULATIONS WILL BE POSSIBLE AS THIS SYSTEM MOVES OFF
TO THE NORTHEAST. WITH SIGNIFICANT DIFFERENCES BETWEEN THE LATEST
MEXMOS AND ECEMOS NUMBERS...DECIDED TO GO WITH A BLEND BETWEEN THE
TWO FOR FORECAST HIGHS AND LOWS ACROSS THE BOARD. PRECIPITATION
COULD BECOME MODERATE AT TIMES SATURDAY NIGHT AND SUNDAY...AS AMPLE
GULF MOISTURE WILL BE FEEDING INTO THE AREA FROM THE SOUTH.

A LARGE AREA OF HIGH PRESSURE WILL THEN SETTLE OVER THE REGION FROM
TUESDAY ONWARD...BRINGING VERY COLD TEMPERATURES TO THE AREA FOR
SEVERAL DAYS. HIGHS TUESDAY ONWARD WILL BE HARD PRESSED TO REACH THE
UPPER 30S FOR MOST LOCATIONS...WITH OVERNIGHT LOWS DROPPING INTO THE
TEENS AND LOWER 20S TUESDAY NIGHT AND WEDNESDAY NIGHT. HIGHS OVER
THE WEEKEND WILL TOP OUT MOSTLY IN THE 30S ON SATURDAY...AND IN THE
40S FOR ALL BUT THE NORTHWESTERN COUNTIES OF THE FORECAST
AREA...WHERE HIGHS WILL ONLY MAKE IT TO THE MID 30S.

&&

.AVIATION...
-- Changed Discussion --
(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 717 AM EST THU DEC 5 2013

CONDITIONS WILL GRADUALLY DETERIORATE THROUGH THE PERIOD AS A COLD
FRONT MOVES SOUTHEAST ACROSS THE COMMONWEALTH AND THEN STALLS JUST
SOUTHEAST OF THE AREA. THIS WILL BRING A PROLONGED PERIOD OF RAIN
WITH IFR CEILINGS/VISIBILITIES AT TIMES. AN AMPLE LOW LEVEL JET
WILL PROVIDE THE THREAT OF LOW LEVEL WIND SHEAR EAST OF I-75 THROUGH
15Z. SOUTH WINDS AT AROUND 10 KTS WILL GRADUALLY VEER TO THE SOUTHWEST
DURING THE DAY...AND THEN SHIFT TO THE NORTHWEST BEHIND THE COLD
FRONT LATER THIS AFTERNOON.
-- End Changed Discussion --

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH SATURDAY MORNING
FOR KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120.
-- End Changed Discussion --

&&

$$

UPDATE...GEOGERIAN
SHORT TERM...GEOGERIAN
LONG TERM...AR
AVIATION...GEOGERIAN