Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 261828
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
228 PM EDT TUE APR 26 2016

.UPDATE...
ISSUED AT 228 PM EDT TUE APR 26 2016

STORM COVERAGE IS INCREASING NORTH OF THE OHIO RIVER...WITH AREAS
RADARS RECENTLY SHOWING A FEW SHOWERS STARTING TO POP UP ACROSS
NORTHERN KENTUCKY. THERE IS SLIGHTLY BETTER SURFACE MOISTURE
ACROSS THE BLUEGRASS REGION...AND LIKELY WILL PROMOTE SOME
ISOLATED SHOWERS/STORMS THROUGH THE REST OF THE AFTERNOON AND
EVENING. WILL UPDATE TO PUSH IN SHOWERS A BIT FASTER FOR AREAS
ALONG AND JUST NORTH OF I-64. OTHERWISE...REST OF THE AREA REMAINS
DRY. CONTINUING TO WATCH A BOWING MCS PUSHING INTO WESTERN
MISSOURI. SPC HAS ALREADY ISSUED WATCHES OUT AHEAD OF THIS COMPLEX
INTO WESTERN KENTUCKY. SOME EASTWARD EXTENSION MAY BE POSSIBLE AS
THIS SYSTEM CONTINUES TO PUSH EAST THIS AFTERNOON. SPC ALSO
EXPANDED THE SLIGHT RISK TO JUST TOUCH OUR FAR WESTERN
COUNTIES...SO WILL HAVE TO WATCH THIS COMPLEX AS IT APPROACHES. IT
SHOULD ARRIVE AFTER 9 PM...SO BIG QUESTION IS CAN IT SUSTAIN
ITSELF INTO THE OVERNIGHT HOURS. LATEST HI-RES GUIDANCE SHOWS IT
WEAKENING SUBSTANTIALLY AS IT CROSSES EASTERN KENTUCKY...SO WILL
CONTINUE TO WATCH THE SHORT TERM MODEL GUIDANCE TO SEE IF THIS
TREND CONTINUES. REGARDLESS...SHOULD SEE SOME MEASURABLE RAIN FOR
MUCH OF THE AREA LATER THIS EVENING.

UPDATE ISSUED AT 1238 PM EDT TUE APR 26 2016

DEWPOINTS HAVE CONTINUED TO CLIMB...BUT CU FIELD STILL LOOKS VERY
WEAK ON VISIBLE SATELLITE AND LOOKING OUT THE WINDOW PRESENTLY.
TEMPERATURES MEANWHILE ARE NEARING 80...PRODUCING SOME WEAK
INSTABILITY ACROSS THE AREA THIS AFTERNOON. THIS SHOULD CONTINUE
TO ENHANCE THE CU ACROSS THE AREA. HOWEVER...MAIN BOUNDARY REMAINS
JUST NORTH OF OHIO RIVER VALLEY...AND BASED ON LATEST
HRRR/ARW/NMM/RAP...LOOKS LIKE ACTIVITY WILL FIRE UP ALONG THAT
BOUNDARY STARTING AROUND 21Z...THEN SLOWLY DRIFT SOUTH...BUT STORM
MOVEMENT SHOULD GENERALLY BE EASTWARD...SO IT MAY TAKE UNTIL AT
LEAST 00Z BEFORE WE SEE ANY ACTIVITY SNEAKING INTO FLEMING COUNTY
IN THE NORTH. THIS SHOULD ALLOW FOR MOST OUTDOOR ACTIVITIES TO
COMMENCE BEFORE RAIN ARRIVES. MCS OVER MISSOURI WILL CONTINUE
SLIDING SOUTH AND EAST INTO THIS EVENING AND HELP BRING THE
BOUNDARY SOUTHWARD AS THIS COMPLEX CROSSES KENTUCKY THROUGH THE
EVENING HOURS. THIS WILL BRING WIDESPREAD SHOWERS AND SCATTERED
THUNDERSTORMS ACROSS MUCH OF EASTERN KENTUCKY BETWEEN 9 PM AND 1
AM TONIGHT. COMPLEX SHOULD GENERALLY BE WEAKENING AS IT DROPS
SOUTHEAST AS INSTABILITY DECREASES...BUT A STRONG WIND GUST OR
HAIL MAY STILL BE POSSIBLE. HAVE INCREASED POPS TO CATEGORICAL FOR
MUCH OF THE AREA TONIGHT. SHOULD SEE RAIN CHANCES TRAIL OFF LATE
TONIGHT AS THE SYSTEM EXITS TO OUR SOUTHEAST...BUT THE FRONTAL
ZONE IN OUR PROXIMITY WILL KEEP AN ISOLATED SHOWER IN THE
FORECAST.

UPDATE ISSUED AT 932 AM EDT TUE APR 26 2016

DEWPOINTS CONTINUE TO RUN WELL UNDER GUIDANCE AND THAT HOLDS INTO
THIS MORNING AND EVEN WITH THE SLIGHT BUMP UP THIS
MORNING...REMAIN UNDER FORECAST VALUES. THUS...HAVE TRIMMED BACK
DEWPOINTS THROUGH THE AFTERNOON/EVENING. THIS WILL ALSO YIELD MUCH
LESS INSTABILITY. MEANWHILE..FRONTAL BOUNDARY REMAINS NORTH OF
THE OHIO RIVER THIS MORNING WITH ONLY A FEW SHOWERS POPPING UP
ALONG THIS BOUNDARY. SHORTWAVE THAT HAD TRIGGERED MORE WIDESPREAD
SHOWERS/STORMS TO OUR NORTH OVERNIGHT IS EXITING EAST. THIS WILL
LEAVE MAINLY DRY CONDITIONS IN TACT FOR MUCH OF TUESDAY. IN
FACT...UNTIL ACTIVITY FIRES ALONG THE FRONT LATER TODAY...WE MAY
NOT SEE MUCH. SOME QUESTION AS TO HOW FAST SHOWERS/STORMS MOVE IN
THIS EVENING. IF THE FRONTAL BOUNDARY STAYS NORTH...WE MAY NOT SEE
MUCH UNTIL A VORT MAX MOVING IN FROM THE WEST CROSSES THE AREA
LATER THIS EVENING (AFTER 9 OR 10 PM). THUS...EXPECT ANOTHER MILD
DAY WITH GENERALLY PARTLY CLOUDY SKIES.

UPDATE ISSUED AT 632 AM EDT TUE APR 26 2016

MID DECK OF CLOUDS CONTINUES TO DEVELOP AND MOVE EAST THIS MORNING
AS SEEN ON FOG CHANNEL...SO UPDATED SKY GRIDS TO BETTER HANDLE
THIS TREND. OVERALL CONVECTION UPSTREAM NEARER THE FRONT HAS BEEN
LIMITED AND WILL HAVE TO SEE HOW THIS TRANSLATES THROUGH THE
MORNING. LATEST CAMS WOULD SUGGEST NOTHING DEVELOPING ACROSS
NORTHERN KY TILL BETWEEN 18Z AND 20Z TIMEFRAME. THEREFORE RIGHT
NOW WILL KEEP POP GRIDS WHERE THEY ARE. OTHERWISE UPDATED
TEMPS/DEWS/WINDS WITH LATEST OBS AND TRENDS.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 339 AM EDT TUE APR 26 2016

SURFACE ANALYSIS SHOWS FRONT AND SURFACE LOW WELL TO OUR NORTH
NEARER THE GREAT LAKES THIS MORNING. CLOSEST CONVECTION RESIDES
ACROSS NORTHERN OH THIS MORNING BASED ON RADAR COMPOSITE. OVERALL
BIGGEST WEATHER CONCERN THIS MORNING WOULD BE THE TEMP SPLITS WITH
VALLEYS RESIDING IN THE LOWER 50S AND RIDGES IN THE MID TO UPPER
60S. THIS BEING AIDED BY CLEAR SKIES AND DECOUPLING IN THE
VALLEYS SPOTS...WHILE IT REMAINS MORE MIXED ON THE RIDGES.

NOW THE AFOREMENTIONED FRONT WILL BE THE FOCUS FOR CONVECTIVE
ACTIVITY THROUGH THE DAY. THINKING THE BOUNDARY REMAINS SLOW TO
WORK SOUTH TODAY AND CAMS WOULD SUGGEST WE SEE LITTLE IF ANY
ACTIVITY BEFORE 20Z. DO THINK CU FIELD WILL BUILD IN AS WE MOVE
INTO THE AFTERNOON...STILL CONCERNED ABOUT OVERALL MOISTURE
RETURN SINCE MODELS HAVE HAD SUCH A PROBLEM AS OF LATE. THAT SAID
KEEP AREAS SOUTH OF I64 CORRIDOR DRY THROUGH MUCH OF THE
DAY...ALSO THE FRONT/LIFTING STAYS NORTH OF THESE AREAS MUCH OF
THE DAY. THIS THOUGHT ALIGNS WELL WITH THE SSEO GREATER THAN 40
DBZ ZONE. THOUGH AS WE MOVE INTO THE LATE AFTERNOON AND EVENING
THIS CONVECTION WILL SINK SOUTH AND WE MAY SEE ADDITIONAL OUTFLOW
BOUNDARIES THAT CAN KICK OFF CONVECTION. ALL THIS SAID SEVERE
POTENTIAL FOR TODAY STILL LOOKS MARGINAL AND AGREE WITH SPC ON
THIS ASSESSMENT. RIGHT NOW BIG LIMITING FACTORS ARE SHEAR AND HOW
MUCH MOISTURE DO WE ACTUALLY REALIZE. IF WE CAN REALIZE THE
INSTABILITY WE CERTAINLY COULD SEE A FEW STRONG/SEVERE
STORMS...WITH DCAPE APPROACHING 1000 J/KG...0-3 KM LAPSE RATES IN
THE 8 C/KM RANGE...AND DECENT CAPE RESIDING IN THE HAIL GROWTH
ZONE. MAIN THREAT WOULD BE SMALL HAIL AND GUSTY WINDS AND BEST
CHANCES WOULD BE ALONG AND NORTH OF THE MOUNTAIN PARKWAY AT THIS
POINT.

THE EVENING AND TONIGHT ADDITIONAL UPPER LEVEL SUPPORT AND FRONT
NEAR BY SHOULD BE ENOUGH TO KEEP REASONABLE CHANCES FOR POPS NORTH
OF THE HAL ROGERS PARKWAY. DO DROP OFF POPS EARLY IN THE DAY ON
WEDNESDAY BEFORE INCREASING POPS THROUGH THE AFTERNOON ON
WEDNESDAY. THIS AS MORE UPPER LEVEL WAVE RIDES ALONG THE MEAN
FLOW INTO THE SOUTHERN OHIO VALLEY. RIGHT NOW WENT WITH CHANCE
STORMS GIVEN THE WEAKER SIGNALS FROM THE FORECAST SOUNDINGS...AND
ALSO THINK BETTER CHANCES FOR MORE ROBUST STORMS WILL BE ACROSS
WESTERN KY.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 415 AM EDT TUE APR 26 2016

A MORE ACTIVE PATTERN THAN WHAT HAS BEEN EXPERIENCED FOR MOST OF
THIS SPRING IS IN STORE. AN UPPER LEVEL LOW WILL LIFT NORTHEAST
FROM THE CENTRAL PLAINS TOWARD THE GREAT LAKES AND EVENTUALLY GET
ABSORBED INTO THE CYCLONIC FLOW ASSOCIATED WITH A DEEP EASTERN
CANADIAN SYSTEM BY LATE FRIDAY. A COUPLE OF SHORTWAVE TROUGHS
MOVING THROUGH THE OH VALLEY...ALONG WITH A SFC LOW MOVING THROUGH
THE OH VALLEY REGION...WITH THE TRAILING COLD FRONT MOVING ACROSS
EAST KY ON THU NIGHT. THESE FEATURES WILL BRING BOUTS OF
UNSETTLED WEATHER TO THE OHIO AND TENNESSEE VALLEYS THROUGH
THURSDAY NIGHT. RIDGING WILL THEN MOVE IN ACROSS THE MISSISSIPPI
VALLEY AND INTO THE OH VALLEY AND APPALACHIANS ON
FRIDAY...PROVIDING A BRIEF PERIOD OF DRY WEATHER THROUGH FRIDAY
NIGHT. MEANWHILE...A SERIES OF SHORTWAVES AND AN UPPER LOW WILL
WORK FROM THE FOUR CORNERS REGION INTO THE CENTRAL PLAINS BY LATE
FRIDAY. THESE LEAD SHORTWAVES SHOULD WORK INTO THE MS VALLEY AND
EVENTUALLY THE OHIO VALLEY BY LATE SATURDAY INTO SUNDAY. THE
UPPER LOW SHOULD MEANDER TO THE MS VALLEY BY THE END OF THE
PERIOD...BUT TIMING AND TRACK UNCERTAINTIES ABOUND. HOWEVER...IT
STILL APPEARS UNSETTLED WEATHER TO THE REGION SATURDAY THROUGH
MONDAY.

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT WILL FEATURE SCATTERED TO
NUMEROUS SHOWERS AND ISOLATED TO POSSIBLY NUMEROUS STORMS ACROSS
EASTERN KENTUCKY. CONVECTION MAY IN FACT BE MOST WIDESPREAD EARLY
IN THE PERIOD...ALTHOUGH DAYTIME HEATING MAY LEAD TO A SECONDARY
PEAK IN COVERAGE ON THU AFTERNOON OR EVENING. THIS SECONDARY PEAK
WOULD BE CONDITIONAL ON DEBRIS CLOUDS AND CONVECTION MOVING OUT
FOR A FEW HOURS OF GOOD HEATING. INSTABILITY AND SHEAR APPEAR TO
BE ON THE MARGINAL SIDE EVEN WITH THE MID LEVEL FORCING AND SFC
LOW MOVING THROUGH THE AREA ON THURSDAY. HOWEVER...A STRONGER
STORM OR TWO WITH GUSTY WINDS AND SMALL HAIL CANNOT BE RULED OUT
THU AFTERNOON TO THU EVENING. OTHER THAN POSSIBLY EARLY ON FRIDAY
NEAR THE VA BORDER...ALL LOCATIONS SHOULD BE DRY ON FRI WITH
CLEARING SKIES AS SHORT WAVE RIDGING MOVES IN.

DISAGREEMENT CONTINUES ON ON HOW QUICKLY FORCING AND MOISTURE
RETURN FROM THE WEST ON SATURDAY. HAVE UNDERCUT THE MODEL BLEND
POPS A TAD AS WAS THE REGIONAL CONSENSUS...BUT HAVE STILL ALLOWED
FOR A CHANCE OF SHOWERS IN THE AFTERNOON. THE RECENT GFS RUNS ARE
QUICKER BRINGING THIS INTO THE REGION COMPARED TO THE ECMWF.
OFTENTIMES WITH SYSTEMS EJECTING FORM THE SW CONUS...THE SLOWER
SOLUTION IS BETTER. AT THIS POINT...IT STILL APPEARS THAT THE
OVERALL BEST CHANCE FOR CONVECTION OVER THE WEEKEND WILL COME
SUNDAY INTO SUNDAY EVENING. HOWEVER...SCATTERED CONVECTION WILL
REMAIN POSSIBLE INTO MONDAY WITH THE TROUGH AXIS WEST OF THE OHIO
VALLEY.

TEMPERATURES WILL AVERAGE ABOVE NORMAL THROUGH THE PERIOD...WITH
HIGHS AVERAGING IN THE UPPER 70S TO AROUND 80 AND LOWS IN THE 50S
TO START THE PERIOD. HIGHS SHOULD BE CLOSER TO NORMAL FOR EARLY
MAY TO END THE PERIOD...THOUGH LOWS SHOULD BE ABOVE NORMAL AS
CLOUD COVER AND PRECIPITATION CHANGES LIMIT DIURNAL RANGES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 228 PM EDT TUE APR 26 2016

VFR CONDITIONS WILL CONTINUE INTO TONIGHT. HOWEVER...A DYING MCS
WILL LIKELY TRAVERSE THE AREA LATE THIS EVENING...BRINGING A ROUND
OF SHOWERS/STORMS TO THE AREA. THIS MAY BRING A BRIEF PERIOD OF
MVFR VISIBILITIES/CIGS AS IT PASSES ACROSS THE AREA. HOWEVER...A
FRONTAL ZONE TO OUR NORTH WILL SHIFT SOUTHWARD OVERNIGHT AND STALL
OVER EASTERN KENTUCKY. TO THE NORTH OF THE BOUNDARY...LOW MVFR/IFR
CIGS WILL DEVELOP. STILL LOTS OF QUESTIONS HOW FAR SOUTH THIS
BOUNDARY REACHES...AND WILL GO AS FAR SOUTH AS JACKSON FOR NOW.
HOWEVER...ITS POSSIBLE MORE OF THE AREA GETS UNDER MVFR/IFR CIGS
BY DAYBREAK WEDNESDAY. DEPENDING ON HOW FAR SOUTH FRONT MAKES
IT...WE MAY BE STUCK IN LOW CLOUDS THROUGH MUCH OF
WEDNESDAY...BUT STILL LOTS OF UNCERTAINTY IN THIS FORECAST.

&&

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

$$

UPDATE...KAS
SHORT TERM...DJ
LONG TERM...JP/PG
AVIATION...KAS



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