Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 010248
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1048 PM EDT SAT APR 30 2016

.UPDATE...
ISSUED AT 1048 PM EDT SAT APR 30 2016

MADE ONE LAST UPDATE TO MAKE SURE THE ONGOING PRECIP WAS WELL
DEPICTED IN THE FORECAST...AS WELL AS TO TWEAK WHAT IS EXPECTED
DURING THE REST OF THE NIGHT. AS WAS PREVIOUSLY DISCUSSED...EVEN
HI RES MODELS ARE STILL HAVING A HARD TIME HANDLING THE ONGOING
PRECIP AS THE WARM FRONT MOVES NORTHWARD. THE HRRR CONTINUES TO
HAVE THE BEST HANDLE OVERALL...SO WENT WITH A MIX OF
OFFICIAL...HRRR...AND HAND TWEEKS TO COME UP WITH EXPECTED
SCENARIO. WE ARE CONTINUING TO SEE A DIMINISHMENT OF RAIN RATES
ACROSS EASTERN KY...SO PROBABLY NOT SEEING MUCH IN CLOUD LIGHTNING
AT THE MOMENT. HOWEVER...RAIN RATES COULD INCREASE...AND A FEW
HEAVIER SHOWERS TO OUR SW MAY MAKE IT INTO THE CWA...SO KEPT
MENTION OF ISOLATED THUNDER THROUGHOUT THE NIGHT AS A PRECAUTION.
IN ADDITION TO THE PRECIP UPDATE...ALSO MADE SURE THE TEMPS...DEW
POINTS...AND WINDS WERE WELL IN LINE WITH THE CURRENT CONDITIONS.
ALL CHANGES HAVE BEEN PUBLISHED AND SENT TO NDFD/WEB...THOUGH
CHANGES SHOULD NOT BE SIGNIFICANT ENOUGH TO WARRANT ANY FURTHER
ZFP UPDATES.

UPDATE ISSUED AT 855 PM EDT SAT APR 30 2016

SHOWERS ARE BEGINNING TO FILL INTO EASTERN KY FROM THE WEST AND
SOUTH AS A WARM FRONT CONTINUES TO LIFT THROUGH THE STATE. MOST OF
THE THUNDERSTORMS THAT HAD DEVELOPED TO OUR SOUTH THIS EVENING
HAVE SINCE WEAKENED AND ARE NOW JUST HEAVY SHOWERS.
HOWEVER...WOULDN/T RULE OUT SOME STRAY THUNDERSTORMS FROM SOME OF
THE HEAVIEST SHOWERS AS THEY MAKE THEIR WAY ACROSS EASTERN KY
OVERNIGHT. GIVEN THE LACK OF MODEL AGREEMENT...TRIED TO BASE NEAR
TERM UPDATED GRIDS ON CURRENT RADAR TRENDS...THEN BLENDED BACK
INTO THE HIRES MODELS THAT SEEM TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION. THIS WILL RESULT IN THE FIRST ROUND OF RAIN
SHOWERS AND ISOLATED THUNDER THROUGH THE NEXT FEW HOURS...THEN
ANOTHER HEAVIER BAND DEVELOPING ACROSS EAST CENTRAL KY AND MOVING
THROUGH THE CWA LATE TONIGHT/EARLY SUN MORNING. GIVEN THE
UNCERTAINTY...WILL CONTINUE TO MONITOR THROUGHOUT THE EVENING IN
CASE ANY FURTHER UPDATES NEED TO BE MADE.

THE OTHER MAIN CHANGE CAME WITH TEMPERATURES. GIVEN THE CLOUDS AND
RAIN...WE HAVE ACTUALLY REMAINED COOLER THAN ORIGINALLY
FORECASTED. THIS RESULTED IN NOT ONLY SOME TWEAKS TO THE CURRENT
TEMPS...BUT ALSO FOR THE DIURNAL CURVE THIS EVENING AND THROUGH
THE OVERNIGHT. AS IT STANDS...WE WILL LIKELY NOT SEE MUCH OF A
DROP DURING THE OVERNIGHT...ESPECIALLY WITH THE EXPECTED
WIDESPREAD RAIN AND CLOUD COVER...SO ONLY EXPECTING A FEW DEGREES
OF VARIATION FROM THE CURRENT ONGOING TEMPS.

ALL CHANGES HAVE BEEN SAVED AND SENT TO NDFD/WEB. A NEW FORECAST
PACKAGE WAS ALSO SENT OUT TO REFLECT THESE CHANGES.

UPDATE ISSUED AT 735 PM EDT SAT APR 30 2016

UNFORTUNATELY MODELS...EVEN HI RES...DO NOT HAVE A GOOD HANDLE ON
THE ONGOING SHOWERS AND THUNDERSTORMS ACROSS KY...TN...AND POINTS
SURROUNDING. HOWEVER...GIVEN THE CURRENT RADAR TRENDS...AN UPDATE
TO POPS AND WEATHER WAS DEEMED NECESSARY. AND MAY BE AGAIN IN THE
NEAR FUTURE DUE TO SHOWERS AND THUNDERSTORMS THAT HAVE NOW
DEVELOPED TO OUR SOUTH. TRIED TO USE THE BEST HI RES MODEL BLEND
AS A STARTING POINT AND THEN HAND TWEAKED GRIDS TO GET DESIRED
POP TREND. ALSO...CHANGED PROBABILITY WORDING TO COVERAGE WORDING
THROUGH THE OVERNIGHT SINCE PRECIP IS ONGOING. ALL CHANGES HAVE
BEEN SAVED AND SENT TO NDFD/WEB...AND NEW FORECAST ZONES WERE SENT
OUT AS WELL TO ADDRESS THE CHANGES.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 400 PM EDT SAT APR 30 2016

CURRENT CONDITIONS ACROSS THE AREA FEATURE AN AREA OF SHOWERS AND
A FEW EMBEDDED THUNDERSTORMS MOVING NORTHEAST AHEAD OF A WARM
FRONT LIFTING NORTH THROUGH THE AREA. AS THIS AREA LIFTS THROUGH
TO THE NORTHEAST...A BREAK IN THE RAIN WILL OCCUR. AS SOUTHERLY
FLOW INCREASES AND THE FRONT SHIFTS NORTH INTO THE AREA...SOME
ADDITIONAL CONVECTION IS EXPECTED TO DEVELOP WITH SOME STORMS
PRODUCING HEAVY DOWNPOURS. WHILE SOME PONDING ON ROADS ARE
POSSIBLE...THE AREA IS FULLY GREENED UP AND WITH PWATS ONLY
REACHING JUST BELOW THE 2ND STANDARD DEVIATION...WILL NOT EXPECT
ANY FLOODING ISSUES TONIGHT. CONCERNING THE STRONG STORM
THREAT...AS THE FRONT APPROACHES TONIGHT...JUST ENOUGH FORCING AND
SHEAR WILL BE AVAILABLE FOR POSSIBLY A STRONG STORM OR TWO. IN
FACT TEMPS WILL REMAIN NEARLY STEADY THROUGH THIS EVENING AND
TONIGHT AS TEMPS ONLY DROP BACK INTO THE LOW 60S.

FOR SUNDAY...AS THE NEXT PIECE OF ENERGY MOVES THROUGH THE
MIDWEST AND INTO THE OH VALLEY...ANOTHER INSTANCE OF STRONG STORMS
WILL BE POSSIBLE. WITH EAST KENTUCKY BEING IN THE WARM
SECTOR...THE CAP OVER THE AREA WILL BE A BIT STOUT. HEADING INTO
THE DAY ON SUNDAY...IF INSTABILITY IS ENOUGH TO BREAK THE CAP AND
CAN OVERCOME THE LOW LEVEL DRY AREA...SOME STRONG STORMS ARE
POSSIBLE ON SUNDAY WITH HAIL AND DAMAGING WINDS THE THREAT. HAVE
MENTIONED THIS IN THE HWO.

HEADING INTO SUNDAY NIGHT...THE FRONT LOOKS TO STALL OUT OVER THE
EAST WITH SOME LINGERING SHOWERS INTO SUNDAY NIGHT.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 311 PM EDT SAT APR 30 2016

THE EXTENDED PERIOD WILL FEATURE PERIODS OF ISOLATED TO SCATTERED
RAIN SHOWERS AND COOLER WEATHER THAT WHAT WE HAVE BEEN
EXPERIENCING THE PAST COUPLE OF WEEKS. THE MODELS ALL HAVE A LARGE
TROUGH OF LOW PRESSURE ALOFT DIVING OUT OF CANADA AND BASICALLY
SPINNING IN PLACE OVER THE SOUTHEASTERN GREAT LAKES REGION AND
SOUTHWESTERN NEW ENGLAND THROUGH OUT THE UPCOMING WORK WEEK. THE
WEATHER SYSTEM THAT WILL BRING SHOWERS AND STORMS TO EASTERN
KENTUCKY TODAY AND TOMORROW...WILL BE DEPARTING THE AREA MONDAY
AND MONDAY NIGHT. ONCE THAT SYSTEM MOVES OFF TO OUR EAST...A MUCH
LARGER AND MORE WELL DEVELOPED TROUGH IS FORECAST TO INFLUENCE THE
WEATHER OF EASTERN KENTUCKY THROUGH THE END OF THE WEEK. MULTIPLE
SHORT WAVES WILL MIGRATE AROUND THE WESTERN PERIPHERY OF THE UPPER
TROUGH...WHICH WILL BRING US PERIODS OF RAIN SHOWERS DURING THE
WEEK. THE RAIN WILL BE LIGHT AND SHOULD NOT PRESENT ANY MAJOR
ISSUES. WE WILL JUST BE IN STORE FOR A DAMP AND CLOUDY WEEK WITH
PERIODS OF SCATTERED RAIN SHOWERS.

TEMPERATURES DURING THE PERIOD WILL GENERALLY RUN AT OR BELOW
NORMAL AS THE TROUGH PULLS COOL MOIST AIR INTO THE REGION. DAY
TIME HIGHS WILL VARY FROM THE LOW TO MID 60S DURING THE RAINIEST
PERIODS...TO AROUND 70 ON THE LESS RAINY LESS CLOUDY DAYS.
OVERNIGHT LOWS WILL MOSTLY BE IN THE 40S ACROSS THE AREA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 745 PM EDT SAT APR 30 2016

A WARM FRONT IS CURRENTLY MAKING ITS WAY NORTHWARD THROUGH KY.
WHILE THIS IS NOT RESULTING IN ANY DRASTIC CHANGES TO THE WINDS OR
DEW POINTS...IT IS GENERATING AN AREA OF SHRA AND TSRA ACROSS
EASTERN TN WHICH ARE PUSHING NORTHWARD TOWARD EASTERN KY. ANOTHER
BATCH OF RAIN IS LOCATED ACROSS CENTRAL KY AND IS NOW MAKING ITS
WAY EASTWARD TOWARD THE TAF SITES AS WELL. TRIED TO TIME OUT THE
ONSET OF THE SHOWERS AND ANY THUNDER POTENTIAL /BEST THUNDER
SHOULD BE WITH ARRIVAL OF SOUTHERN STORMS AFTER 5Z/. UNFORTUNATELY
MODELS DO NOT HAVE A GREAT HANDLE ON THE ONGOING PATTERN...SO
RELIED ON UPSTREAM OBSERVATIONS FOR EXPECTED VIS AND CIG IMPACTS.
HOWEVER...SINCE MOST OF THE WEATHER WILL BE IMPACTING US DURING
THE OVERNIGHT...THESE PARAMETERS MAY NEED TO BE TWEAKED SOMEWHAT
AS IT NEARS. GENERALLY EXPECTING MVFR CIGS WITH SOME VIS DROPPING
INTO THE IFR CATEGORY IN THE HEAVIEST RAINS. THE SAME IS TRUE FOR
THE THUNDER POTENTIAL...SO GIVEN LOW CONFIDENCE ON IF THE BEST
CONVECTION WILL MAKE IT INTO OUR AREA...ONLY INCLUDED VCTS AT THIS
TIME.

A BREAK IN THE ACTION WILL LIKELY TAKE PLACE AFTER 8Z AS THE WARM
FRONT CONTINUES TO SHIFT NORTH. CONDITIONS WILL DEGRADE DURING THE
DAY TOMORROW AS THE NEXT DISTURBANCE PRODUCES MORE CONVECTION
TOMORROW AFTERNOON. EXACT IMPACTS AND TIMING OF THESE STORMS IS
STILL UNKNOWN. WINDS WILL BE LIGHT OUT OF THE EAST OVERNIGHT BEFORE
SHIFTING AROUND TO THE SOUTHWEST TOMORROW MORNING AND INCREASING
UP TO 10 KNOTS.

&&

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

$$

UPDATE...JMW
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...JMW



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