Area Forecast Discussion
Issued by NWS Jackson, KY

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037
FXUS63 KJKL 051730
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
130 PM EDT THU MAY 5 2016

.UPDATE...
ISSUED AT 108 PM EDT THU MAY 5 2016

BIGGEST ISSUE THIS AFTERNOON HAS BEEN SOME REDEVELOPMENT OF
SHOWERS IN THE CENTER PART OF THE CWA THIS AFTERNOON. THE HRRR
DOES HAVE SOME HINT AT THIS OTHERWISE SEEMS LIKE CAMS HAVE BEEN A
BIT BEHIND ON THIS THOUGHT. THESE SHOWERS ARE LIKELY DO TO SOME
BREAKS IN SKY COVER SEEN ON VIS SAT AND VISUALLY HERE AT
JKL...THIS HAS LEAD TO STEEPING LOW LEVEL LAPSE RATES THAT WILL
TEAM UP WITH ALREADY STEEP MID LEVEL LAPSE RATES. MOST OF THIS
WILL REMAIN LIGHT AND STILL NOT EXPECTING ANY LIGHTNING WITH THIS
ACTIVITY AT THIS TIME. THEREFORE GIVEN TREND DID HAVE TO
REEVALUATE AND UPDATE THE HOURLY POP GRIDS TO DEAL WITH LATEST
OBS...REMOTE SENSING DATA...AND CAM TRENDS. OTHERWISE JUST MORE
MINOR UPDATES TO TEMPS...DEWS...AND WINDS.

UPDATE ISSUED AT 1052 AM EDT THU MAY 5 2016

UPPER LEVEL COLD CORE LOW CENTERED ACROSS EASTERN KY THIS MORNING
BASED ON HRRR AND WATER VAPOR IMAGERY. WHILE IT WRAPS UP ACROSS
THE REGION DECENT COVERAGE OF SHOWERS RESIDES GENERALLY ALONG AND
SOUTH OF THE HAL ROGERS PARKWAY BASED OFF COMPOSITE WSR-88D RADAR
DATA. THAT SAID THESE SHOWERS WILL SLIDE SOUTHEAST INTO EASTERN TN
THROUGH THE AFTERNOON...AS THESE SHOWERS SLIDE OUT MORE SHOWERS
WILL SLIDE IN FROM WEST VA. THESE LOOK TO MAINLY AFFECT THE FAR
EAST AND NORTHEAST IN TERMS OF COVERAGE. THIS THINKING SEEMS TO
BE REASONABLE BASED ON THE CAMS...SPC SSEO...AND RADAR TRENDS.
GIVEN THE CURRENT SETUP LOW CONFIDENCE IN SEEING ANY THUNDER TODAY
AND THEREFORE WILL CONTINUE TO KEEP OUT OF THE FORECAST. OVERALL
TEMPS ARE ON TRACK AND COULD BE LOOKING AT MINIMUM HIGH
TEMPERATURE RECORD TODAY WHICH IS 52 DEGREES AT JKL BACK IN 2013.
UPDATED POPS/TEMPS/DEWS/WINDS WITH LATEST OBS AND TRENDS.

UPDATE ISSUED AT 656 AM EDT THU MAY 5 2016

RAIN SHOWERS CONTINUE TO EXPAND AS THEY WORK INTO EASTERN KENTUCKY
THIS MORNING. IT LOOKS LIKE SHOWERS SHOULD AFFECT MOST OF EASTERN
KENTUCKY THIS MORNING...WITH THE EXCEPTION OF FAR NORTHEAST
KENTUCKY. FOR THIS REASON...HAVE INCREASED POPS AREAWIDE THROUGH
THE MORNING HOURS AS THIS VORT MAX DROPS SOUTH WITH THE ASSOCIATED
SHOWER ACTIVITY. STILL LOOKS LIKE WE SHOULD SEE A LULL IN SHOWERS
FROM LATE MORNING THROUGH EARLY AFTERNOON...BEFORE MORE SHOWERS
PUSH IN FROM THE EAST. BLACK MOUNTAIN HAS DROPPED OFF TO 32
DEGREES...SO IT LOOKS LIKE A FEW SNOW SHOWERS COULD BE SEEN THERE.
OTHERWISE...SHOULD BE ALL RAIN.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 259 AM EDT THU MAY 5 2016

DEEP UPPER LEVEL LOW IS PRESENTLY MOVING ACROSS SOUTHEAST OHIO.
EASTERN KENTUCKY REMAINS DRY AS ALL THE SHOWER ACTIVITY HAS
SHIFTED SOUTH AND EAST OF THE AREA. HOWEVER...A VORT MAX IS
DROPPING SOUTH ON THE BACK SIDE OF THE UPPER LOW WITH SCATTERED TO
NUMEROUS SHOWERS DROPPING SOUTHEAST ACROSS SOUTHERN INDIANA...INTO
NORTH CENTRAL KENTUCKY. THESE SHOWERS SHOULD CONTINUE TO WORK
SOUTHWARD THIS MORNING...AND LIKELY CLIP THE COUNTIES IN THE
CUMBERLAND VALLEY...OR AREAS ALONG AND WEST OF I-75. WILL MAINTAIN
LIKELY POPS AS THIS ACTIVITY DROPS SOUTH...BUT MAY DECIDE TO GO UP
TO CATEGORICAL IF SHOWERS HOLD TOGETHER OVER THE NEXT FEW HOURS.
EITHER WAY...LOOKS LIKE A DAMP MORNING FOR THE CUMBERLAND VALLEY.
AS THE VORT MAX EXITS SOUTH THIS MORNING...SURFACE WINDS SHOULD
BACK TO THE NORTHWEST AND WE MAY SEE SOME UPSLOPE SHOWERS DEVELOP
ON THE NORTHEAST FLANK OF THE DEPARTING VORT MAX. WITH 850MB TEMPS
GETTING CLOSE TO -1C THIS MORNING...IT WOULD BE POSSIBLE FOR A FEW
SNOW FLAKES ON BLACK MOUNTAIN. THIS SHOWER ACTIVITY WOULD MAINLY
IMPACT SOUTHEAST KENTUCKY. THIS ACTIVITY WILL THEN SHIFT SOUTH BY
MIDDAY.

OUR ATTENTION THEN TURNS BACK TO THE NORTH AND EAST AS ANOTHER
SHORTWAVE DROPS SOUTH FROM OHIO. THIS TIME AROUND...IT LOOKS LIKE
THE EASTERN HALF OF THE FORECAST AREA IS SET TO BE IMPACTED WITH
WIDESPREAD SHOWERS DEVELOPING FROM MID TO LATE AFTERNOON. HAVE
GONE MUCH HIGHER WITH POPS AS MOISTURE AND LIFT SHOULD BE
ABUNDANT. WE ALSO HAVE UPSLOPE FLOW WHICH WILL HELP TO ENHANCE ANY
SHOWER ACTIVITY. WHILE MODELS HAD INDICATED SOME WEAK INSTABILITY
YESTERDAY...TODAYS RUNS HAVE LOOKED MUCH LESS FAVORABLE...SO
DESPITE THE LOW FREEZING LEVELS...WILL MAINTAIN NO THUNDER. IF WE
WERE TO GET SOME STORMS...HAIL WOULD BE A DEFINITE POSSIBILITY WITH
THE LOW FREEZING LEVELS. BY TONIGHT...THE WAVE WILL EXIT
SOUTH...BUT UPSLOPE FLOW WILL CONTINUE. THUS...WILL MAINTAIN SOME
LOW POPS FOR SOUTHEAST KENTUCKY OVERNIGHT TO ACCOUNT FOR SOME
LINGERING SHOWERS IN THE UPSLOPE FLOW REGIME. FINALLY...ON
FRIDAY...ONE LAST WAVE LOOKS TO DROP SOUTH WITH A POSSIBLE UPTICK
IN SHOWER ACTIVITY ACROSS EASTERN KENTUCKY.

TEMPERATURES WILL BE VERY COOL OVER THE NEXT 24 TO 36 HOURS. WITH
TEMPERATURES STARTING OFF AROUND 40 THIS MORNING...HAVE CUT BACK
HIGHS FOR TODAY BASICALLY BACK INTO THE LOW 50S...BUT WOULD NOT BE
SURPRISED TO SEE A FEW LOCATIONS FAILING TO CRACK 50...ESPECIALLY
ON THE RIDGES. LOWS TONIGHT WILL DIP BACK INTO THE 40S...BUT CLOUD
COVER SHOULD PREVENT THEM FROM GOING TOO MUCH LOWER THAN HIGHS
TODAY. ON FRIDAY...BOUNDARY LAYER SHOULD WARM SLIGHTLY ALLOWING
FOR A SLIGHTLY MILDER DAY WITH TEMPERATURES BACK INTO THE 60S.
STAYED BELOW GUIDANCE HOWEVER...GIVEN THE UNCERTAINTY WITH CLOUD
COVER AND SHOWER ACTIVITY POSSIBLY KEEPING TEMPERATURES A BIT
LOWER.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 425 AM EDT THU MAY 5 2016

THE MODELS ARE IN FAIR AGREEMENT ALOFT THROUGH THE EXTENDED
PORTION OF THE FORECAST. THEY ALL DEPICT A DEAMPLIFYING OF THE
INITIAL BLOCKY PATTERN AS A PAIR OF UPPER LOWS OVER THE CONUS
WEAKEN AND SHIFT EAST NORTHEAST. THE MID ATLANTIC ONE WILL LOSE
ITS INFLUENCE OVER EASTERN KENTUCKY EARLY IN THE WEEKEND AS IT
STARTS TO MOVE OFF SHORE. THIS WILL ALLOW HEIGHT RISES AND RIDGING
TO SPREAD INTO THE BLUEGRASS STATE FROM THE SOUTHWEST. THIS RIDGE
WILL BE LIMITED FOR OUR PART OF THE REGION BY ADDITIONAL
TROUGHINESS OVER THE GREAT LAKES AND EXTENDING SOUTH INTO THE OHIO
VALLEY FOR SATURDAY NIGHT AND SUNDAY. THIS WILL ALSO KEEP THE AREA
PRIMED FOR WEAK SHORT WAVES TO PASS OVERHEAD IN FAIRLY FAST
NORTHWEST FLOW. IN GENERAL...THE GFS IS STRONGER WITH THE GREAT
LAKES TROUGH THAN THE OTHER MODELS AND WILL BE DAMPENED OUT VIA
THE BLEND FOR GRIDDED FORECAST PURPOSES. MEANWHILE...FOR THE
LATTER PART OF THE WEEKEND AND INTO THE NEW WORK WEEK THE WESTERN
TROUGH WILL MOVE INTO THE HIGH PLAINS AND OPEN UP ALLOWING BITS OF
ITS ENERGY TO SLIP EAST THROUGH THE OHIO VALLEY AND ACROSS THE
NORTHERN PORTION OF THE NOW WEAKENING SOUTHEAST RIDGE. THIS ACTION
IS PROGRESSIVE ENOUGH THAT IT EVENTUALLY RESULTS IN THE MID LEVEL
RIDGE AXIS MOVING OFF TO THE EAST OF KENTUCKY AND MORE BOUTS OF
ENERGY MOVING OVER OUR CWA IN SOUTHWEST FLOW. THE PATTERN THEN
CONTINUES ITS EVOLUTION THROUGH THE MIDDLE OF NEXT WEEK ENDING UP
WITH TROUGHING NORTH OF THE AREA AND FLATTER...MORE ZONAL...
HEIGHTS TO THE SOUTH ALONG WITH LIMITED PACKETS OF ENERGY PASSING
THROUGH THE REGION. GIVEN THE COMPLICATIONS OF THIS EVOLVING
PATTERN WILL STICK FAIRLY CLOSE TO THE BLENDED MODEL SOLUTION
THROUGH THE EXTENDED PORTION OF THE FORECAST.

SENSIBLE WEATHER WILL FEATURE A RETURN TO MORE SEASONABLE
TEMPERATURES FOR SATURDAY AS THE STACKED LOW TO OUR EAST LOSES
ITS INFLUENCE. AS PART OF THIS PROCESS...A DEVELOPING WARM FRONT
PASSES THROUGH KENTUCKY FRIDAY NIGHT INTO EARLY SATURDAY WITH A
CHANCE FOR SHOWERS INITIALLY AND THEN THUNDERSTORM POSSIBILITIES
THAT AFTERNOON. IN FACT...ANY STORMS THAT MANAGE TO DEVELOP
SATURDAY AFTERNOON COULD BECOME STRONG GIVEN MODERATE CAPE...LOW
LIS...AND VEERING WINDS WITH HEIGHT. A COLD FRONT WILL THEN SLIP
SOUTH INTO THE AREA SATURDAY NIGHT INTO SUNDAY. THIS FRONT WILL
HANG UP OVER EAST KENTUCKY INTO THE START THE NEW WEEK. WITH
THIS...SHOWERS AND THUNDERSTORMS CAN BE ANTICIPATED. ON SUNDAY
THE FRONT AND PCPN WILL LIKELY KEEP TEMPS IN THE 60S FOR HIGHS
OVER ALL BUT THE FAR SOUTHWEST. TEMPERATURES WILL DO BETTER FOR
THE REST OF THE WEEK AS THE FRONT LIFTS BACK NORTH WITH MID AND
UPPER 70S ANTICIPATED. THIS SHOULD BE ENOUGH TO FUEL THE
INSTABILITY ALLOWING FOR CHANCES OF THUNDERSTORMS ALONG WITH ANY
SHOWERS DURING THE BULK OF THE EXTENDED FORECAST.

AS FOR THE CR INIT...MADE ONLY MINOR ADJUSTMENT TO TEMPERATURES
EACH NIGHT ANTICIPATING MINIMAL RIDGE TO VALLEY DIFFERENCES ASIDE
FROM SATURDAY AND TUESDAY MORNINGS. ALSO TWEAKED THE POPS FOR THE
LATTER PART OF THE FORECAST MORE ALONG THE LINES OF THE LATEST
ECMWF.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 130 PM EDT THU MAY 5 2016

CIGS ARE IN THE VFR TO MVFR RANGE TO BEGIN THE PERIOD...THE MVFR
SITES HAVE BEEN IN FLUX. THAT SAID OVERALL SYNOPTICALLY WE ARE
SEEING A UPPER LEVEL LOW TRACK RIGHT ACROSS THE AREA AND NOW IT
HAS SHIFT SE INTO EASTERN TN THIS AFTERNOON. THE BREAKS IN THE
CLOUD COVER HAVE LEAD TO A FEW SHOWERS ACROSS THE REGION MAINLY AT
JKL...LOZ...AND SME. HOWEVER MORE SHOWERS ARE EXPECTED TO DEVELOP
AND TRACK INTO THE FAR EAST AND NORTHEAST. OVERALL EXPECTING LOW VFR
TO BE PRODOMINATE CIGS...BUT OCCATIONAL MVFR NOT OUT OF THE
QUESTION WITH HEAVIER SHOWERS. THE CLOUDS TONIGHT WILL BE TRICKY
AND UPSLOPE MAY HELP KEEP STRATO CU GOING...HOWEVER IF WE SEE
GREATER REDUCTIONS FOG CONCERNS WOULD NEED TO BE EVALUATED
PARTICULARLY IN THE VALLEY TAF SITES. OVERALL WINDS WILL REMAIN
LIGHT...BUT SOME GUSTS WOULD BE POSSIBLE FRIDAY AFTERNOON MORE
PAST THE TAF PERIOD.

&&

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

$$

UPDATE...DJ
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...DJ



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