Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 190910
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
410 AM EST WED NOV 19 2014

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 345 AM EST WED NOV 19 2014

07Z SFC ANALYSIS SHOWS HIGH PRESSURE OVER EASTERN KENTUCKY. THE
CLEAR SKIES IN PLACE...LIGHT WINDS...AND LOW DEWPOINTS ARE MAKING A
RECORD SETTING COLD NIGHT EVEN COLDER FOR THE VALLEYS THROUGH THE
AREA DUE TO AN INVERSION AND RADIATIONAL COOLING. CURRENTLY READINGS
ARE VARYING FROM NEAR 10 DEGREES IN THE DEEPER VALLEYS TO THE MID
AND UPPER TEENS ON THE RIDGES. DEWPOINTS...MEANWHILE...ARE RUNNING
IN THE SINGLE DIGITS.

THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A DEEP TROUGH GENERALLY ON
THE WANE OVER THE OHIO VALLEY BUT WITH A SLIGHT RESURGENCE TAKING
PLACE INTO THURSDAY MORNING DUE TO A SHARP SHORTWAVE CROSSING THE
GREAT LAKES. THIS PROCESS LURES A WEAK ENERGY STREAM NORTH INTO
KENTUCKY DURING THE DAY THURSDAY AS THE LARGER TROUGH STARTS TO MOVE
OFF TO THE NORTHEAST. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED THE
HIGHER RESOLUTION NAM12 AND HRRR MODELS FOR THE WX DETAILS.

SENSIBLE WEATHER WILL FEATURE A VERY COLD START TO THE DAY WITH
READINGS SOME 5 DEGREES OR SO BELOW RECORD LEVELS IN MANY PLACES
ACROSS EAST KENTUCKY. WITH AMPLE SUNSHINE IN THE MORNING...
TEMPERATURES WILL CLIMB SMARTLY SO THAT HIGHS WILL BE AT LEAST 10
DEGREES WARMER THAN YESTERDAY THROUGHOUT THE AREA. HOWEVER...HIGH...
AND LATER LOWER CLOUDS...WILL BE ON THE INCREASE DURING THE
AFTERNOON FROM THE NORTHWEST AHEAD OF AN APPROACHING CLIPPER SYSTEM
AND ITS TRAILING COLD FRONT. THIS FRONT WILL PRESS INTO THE AREA
WITH A POCKET OF LOW LEVEL MOISTURE CAPABLE OF GENERATING LIGHT PCPN
WHEN COMBINED WITH THE SMALL LIFT ACCOMPANYING THE FRONT. THE
QUESTION BECOMES P-TYPE GIVEN THE COLD TEMPERATURES ALOFT AND DEPTH
OF...OR LACK THEREOF...MOISTURE. IT DOES LOOK LIKE THERE WILL BE
JUST ENOUGH MOISTURE AT THE COLDER TEMPERATURES TO GENERATE ICE
CRYSTALS FOR SNOW AND SO THAT WAS THE MAIN WX FORECAST FOR TONIGHT.
HOWEVER...SHOULD THIS NOT OCCUR...POCKETS OF FREEZING DRIZZLE WILL
BE POSSIBLE. NEVERTHELESS...ONLY A HUNDREDTH OR TWO OF LIQUID
EQUIVALENT IS EXPECTED FROM THIS FRONT SO IT IS A MARGINAL
CONCERN...BUT ONE WORTH NOTING. LOW CLOUDS WILL THEN LINGER OVER THE
AREA THROUGH THE REST OF THE DAY THURSDAY WITH LITTLE PUSH TO CLEAR
THEM OUT...HINDERING OUR TEMPERATURE RECOVERY.

USED THE BCCONSSHORT GUIDANCE FOR THE STARTING POINT OF THE T/TD AND
WIND GRIDS THROUGH THE FIRST PART OF TONIGHT AND THE SUPERBLEND
THEREAFTER. DID MAKE SOME MINOR ADJUSTMENTS FOR THE TERRAIN
DIFFERENCES THROUGHOUT THE PERIOD. AS FOR POPS...ENDED UP HIGHER
THAN ALL THE GUIDANCE TONIGHT...IN THE SCATTERED RANGE OF THE WX
COVERAGE TERM.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 409 AM EST WED NOV 19 2014

A STRONG UPPER LEVEL TROUGH ACROSS MUCH OF THE NE CONUS WILL
CONTINUE TO SHIFT EASTWARD AS WE HEAD INTO THURSDAY NIGHT. AS A
RESULT...MUCH OF THE OHIO RIVER VALLEY REGION CAN EXPECT INCREASING
HEIGHTS AND SURFACE HIGH PRESSURE TO BE MOVING IN. WITH BOTH DRY AIR
IN THE MID AND UPPER LEVELS...THIS WILL PRODUCE STRONG RADIATIONAL
COOLING AND ALLOW TEMPERATURES TO DROP BACK DOWN INTO THE UPPER
TEENS AND LOW 20S ONCE MORE. LUCKILY...WINDS NEAR THE SURFACE WILL
BE FAIRLY LIGHT...SO DON/T EXPECT THE WIND CHILL FACTOR TO BE MORE
THAN A FEW DEGREES COOLER. WHAT IS OF CONCERN...HOWEVER...IS THE LOW
LEVEL MOISTURE THAT COULD BE LINGERING FROM THE PREVIOUS DAY.
ACCORDING TO THE LATEST FORECAST SOUNDINGS...A STRONG SUBSIDENCE
INVERSION SETS UP THURSDAY NIGHT...TRAPPING A LAYER OF LOW LEVEL
MOISTURE NEAR THE SURFACE. GIVEN THE EXPECTED TEMPERATURES...IF ANY
FOG DEVELOPS FROM THIS...COULD BE LOOKING AT A FREEZING FOG EVENT.

HIGH PRESSURE SHOULD HOLD ON THROUGH FRIDAY NIGHT...WITH HEIGHTS
ALOFT CONTINUING TO INCREASE. THIS WILL ALLOW TEMPS TO RISE INTO THE
UPPER 30S AND LOW 40S ON FRIDAY AFTERNOON...AND THEN INTO THE 50S AS
WE HIT SATURDAY AFTERNOON. THERE WILL BE A DISTURBANCE WHICH IS
POSED TO MOVE INTO THE AREA DURING THE WEEKEND. AS A RESULT...EXPECT
CLOUD COVER TO SPREAD ACROSS EASTERN KY AHEAD OF THE SYSTEM
THROUGHOUT FRIDAY NIGHT. THE LOW LEVELS LOOK TO BE QUITE DRY...WITH
A WARM NOSE ABOVE FREEZING JUST ABOVE THE SURFACE. AS A RESULT...DO
NOT EXPECT ANY FURTHER CONCERNS FOR FOG OR FREEZING PRECIP DURING
THIS TIME PERIOD...BUT IF ANY PRECIP DOES MAKE IT INTO OUR WESTERN
FRINGE COUNTIES BY 12Z SATURDAY...COULD SEE SOME SLIGHT CHANCES FOR
FREEZING RAIN.

DAYS 4 THROUGH 7...

MODELS ARE IN FAIRLY GOOD AGREEMENT WITH UL PATTERN THROUGH THIS
PERIOD. UL RIDGING GRADUALLY SHIFTS EWRD OVER THE ATLANTIC AS A
BROAD UL TROF MOVES OVER THE EASTERN CONUS ON MONDAY. THE UL TROF
WILL BE THE DOMINATE WX PATTERN FROM MONDAY THROUGH THE END OF THE
PERIOD.

AT LOWER LEVELS... LL MOISTURE INCREASES SATURDAY AHEAD OF THE NEXT
SYSTEM THAT WILL EJECT OUT OF THE SOUTHERN PLAINS. THIS SYSTEM IS
FORECASTED TO QUICKLY MOVE NEWD ACROSS THE CWA SUNDAY AFTERNOON.
SINCE IT IS QUICK MOVING...THE MAIN BATCH OF PRECIP IS FORECASTED TO
AFFECT THE AREA SUNDAY AFTERNOON AND EVENING. IN TERMS OF THE
GRIDS...HAVE SLOWED DOWN THE ONSET OF THE PRECIP FROM PREVIOUS
FORECAST SINCE THE GFS/ECMWF KEPT PRECIP OUT OF THE CWA UNTIL 12Z
SUNDAY.

AS THE SYSTEM LIFTS NEWD...THERE MAY BE SOME ADDITIONAL PRECIP
ASSOCIATED WITH THE SFC LOW...AND ADDITIONAL S/WV ENERGY MOVING
THROUGH THE BASE OF THE TROF. DEPENDING ON THE LOWS TRACK AND HOW IT
PHASES WITH THE NORTHERN STREAM ENERGY...CLOUDS AND A CHANCE FOR
PRECIP COULD LINGER THROUGH TUESDAY MORNING. BOTH THE GFS AND ECMWF
DIFFER IN REGARDS TO THE PHASING OF THE NORTHERN AND SOUTHERN STREAM
ENERGY...SO HAVE KEPT CHANCES FOR RAIN IN THE GRIDS THROUGH MONDAY
EVENING. TUESDAY AND WEDNESDAY APPEAR TO BE MOSTLY QUIET AS THE SFC
TROF SLOWLY MOVES OUT AND HIGH PRESSURE BUILDS INTO THE REGION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 130 AM EST WED NOV 19 2014

THE TAF SITES WILL EXPERIENCE VFR CONDITIONS FOR THE BULK OF THE TAF
PERIOD. HOWEVER CLOUD COVER WILL DEVELOP AND THICKEN BY WEDNESDAY
EVENING FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA AS A CLIPPER
SYSTEM EJECTS OUT OF THE NORTHERN PLAINS AND ACROSS THE LOWER GREAT
LAKES REGION. AFTER 00Z A FEW SNOW SHOWERS WILL BE POSSIBLE FROM THIS
SYSTEM AND A VCSH WAS ADDED TO THE TAFS. WINDS WILL BE LIGHT AND
VARIABLE THROUGH THE REST OF THE NIGHT. THEY ARE THEN EXPECTED TO BE
GUSTY TOMORROW FROM THE SOUTH TO SOUTHWEST WITH INCREASING INTENSITY
AFTER 15Z TO AROUND 10 KTS SUSTAINED...GUSTING TO AROUND 20 KTS.


&&

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

$$

SHORT TERM...GREIF
LONG TERM...JMW/JVM
AVIATION...GREIF





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