Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 282053 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 353 PM EST SAT FEB 28 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 350 PM EST SAT FEB 28 2015 WINDS WILL SHIFT TO A MORE SRLY DIRECTION ON THE BACKSIDE OF EXITING HIGH PRESSURE THIS EVENING...CREATING A PSEUDO WARM FRONTAL BOUNDARY ALONG A DEVELOPING LLVL JET. OVERRUNNING PRECIP WILL THEN DEVELOP BY THIS EVENING IN NORTHERN PORTIONS OF CENTRAL KENTUCKY...INTO INDIANA AS WELL AS OHIO. THIS WILL BRING PRECIP INTO EASTERN KENTUCKY BY OR SHORTLY AFTER 06Z TONIGHT. THERE CONTINUES TO BE A FEW CONCERNS WITH THIS SYSTEM...NAMELY A LIGHT ICE AND SNOW POTENTIAL. LATEST FORECAST SOUNDINGS ARE CONTINUING TO SUPPORT A STEADY OR GRADUAL WARMING OF TEMPS THROUGHOUT THE NIGHT AS SOUTHERLY WINDS... CLOUD COVER...AND PRECIP TAKE CONTROL. HOWEVER...GIVEN THE ANTECEDENT COLD CONDITIONS...IT IS LIKELY THAT EVEN AS SURFACE TEMPS SLOWLY RISE...THE PAVEMENT AND GROUND TEMPS WILL TAKE AN HOUR TO 3 HOURS LONGER. TEMPERATURES IN THE LLVLS WILL RISE ABOVE FREEZING BETWEEN 0 AND 6Z...HOWEVER...SURFACE TEMPS WILL LIKELY LAG BEHIND BY A FEW HOURS. THIS WILL CREATE THE SET UP FOR SOME SNOW/IP POTENTIAL JUST AT ONSET /AND CONTINUING IN THE NORTH FOR A BIT LONGER/...THEN A FREEZING RAIN POTENTIAL GIVEN THE LATEST NAM12 AND GFS40 FORECAST SOUNDINGS THROUGH AROUND 12Z...BEFORE SURFACE TEMPS FINALLY WARM ENOUGH ACROSS THE REGION THAT ALL PRECIP FALLS AS RAIN AFTER 12Z TO 15Z. GIVEN THE WARMER SRLY FLOW TOMORROW...TEMPS WILL FINALLY INCREASE TO CLOSER TO SEASONABLE NORMAL VALUES DURING THE AFTERNOON...GENERALLY IN THE 40S. FROM HERE...FORECAST SOUNDINGS SHOW A DEEP LAYER OF MOISTURE CONTINUING THROUGHOUT THE DAY AND INTO THE OVERNIGHT HOURS SUNDAY NIGHT WITH SOME CONTINUOUS/WIDESPREAD RAINFALL POSSIBLE. RAIN WILL THEN CHANGE BACK OVER TO SNOW AS TEMPS DROP BELOW FREEZING AFTER DARK...BEFORE FINALLY LOSING INTENSITY AND TAPERING OFF MONDAY MORNING AS HIGH PRESSURE MOVES IN OVERHEAD. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 400 AM EST SAT FEB 28 2015 VERY ACTIVE AND MESSY WEATHER ON TAP IN THE EXTENDED. THE GFS AND ECMWF MODELS WERE NOT IN THE BEST OF AGREEMENT REGARDING PRECIP ONSET AND EVOLUTION DURING THE PERIOD...WITH THE ECMWF BEING SLOWER AND NOT QUITE AS WET AS THE GFS TO BEGIN THE PERIOD. THE INITIAL PRECIP EVENT LOOKS TO BE IN FULL SWING SUNDAY NIGHT AND MONDAY...AS A COLD FRONT PUSHES ACROSS THE AREA. MOST OF THE PRECIP WITH THIS FIRST BOUNDARY SHOULD BE IN THE FORM OF RAIN. SOME SNOW IS EXPECTED TO DEVELOP IN THE MOIST UPSLOPE FLOW BEHIND THE DEPARTED FRONT ON MONDAY. ANY ACCUMULATIONS WITH THIS SNOW SHOULD BE MINIMAL AT BEST. A RIDGE OF HIGH PRESSURE IS THEN EXPECTED TO SETTLE OVER THE AREA FOR A SHORT PERIOD OF TIME MONDAY AFTERNOON AND EVENING. THEN...A SECOND MORE DYNAMIC WEATHER SYSTEM IS PROGGED TO TAKE SHAPE OVER THE SOUTHERN PLAINS. THIS SYSTEM IS EXPECTED TO MOVE NORTHWARD...PUSHING ITS WARM FRONT ACROSS THE TENNESSEE AND OHIO VALLEY REGIONS MONDAY NIGHT THROUGH MONDAY MORNING. MOIST AIR OVERRUNNING THE FRONT MAY ALLOW FOR A MESSY MIX OF RAIN...FREEZING RAIN...AND PERHAPS SOME SNOW DURING THIS PERIOD. LIGHT ICE ACCUMULATIONS WILL BE POSSIBLE...ESPECIALLY NORTH OF THE MOUNTAIN PARKWAY...WHERE A COUPLE OF HUNDREDTHS OF AN INCH OF ICE MAY ACCUMULATE ON EXPOSED AND ELEVATED SURFACES. THE AIR AT THE SURFACE SHOULD BE WARM ENOUGH MY MIDMORNING ON TUESDAY FOR THE PRECIP TO FALL AS ALL RAIN. ONCE THE WARM FRONT HAS PAST US BY...A STRONG COLD FRONT IS THEN ON TAP TO PUSH ACROSS THE AREA FROM THE NORTHWEST. THIS BOUNDARY WILL LINGER ACROSS THE AREA FOR A COUPLE OF DAYS. WIDESPREAD RAIN SHOWERS...CAPABLE OF PRODUCING MODERATE TO LOCALLY HEAVY RAIN AT TIMES...WILL OVERSPREAD THE AREA TUESDAY THROUGH WEDNESDAY. THIS RAIN IN AND OF ITSELF MAY LEAD TO FLOODING ISSUES. COMBINE THIS RAIN WITH RUNOFF FROM MELTING SNOW...AND THINGS MAY GET INTERESTING. THE PRIMARY CONCERN WITH THIS EVENT WILL BE WARMING TEMPERATURES AND THE MELTING OF THE SNOW PACK THAT IS CURRENTLY IN PLACE IN THE HEADWATERS OF THE KENTUCKY...CUMBERLAND...AND BIG SANDY RIVERS. WITH THE MODELS STILL PRODUCING A GOOD DEAL OF PRECIP TO BEGIN THE WEEK...WE WILL CONTINUE TO HIGHLIGHT THE POTENTIAL FOR FLOODING NEXT WEEK. THE PRECIPITATION IS EXPECTED TO LINGER THROUGH THE END OF THE DAY ON THURSDAY BEFORE FINALLY MOVING OF TO OUR EAST. THE RAIN WILL CHANGE TO SNOW WEDNESDAY EVENING...AS COLD AIR BEGINS FILTERING INTO THE REGION BEHIND THE COLD FRONT. AS WINDS SHIFT TO THE NORTH...AND UPSLOPE FLOW BEGINS TO OCCUR...THE SNOW WILL BECOME MORE WIDESPREAD. LIGHT ACCUMULATIONS WILL BE POSSIBLE AS SNOW MOVES OVERSPREADS THE ENTIRE AREA BY LATE WEDNESDAY NIGHT. THE SNOW WILL TAPER OFF THURSDAY MORNING AS THE FRONT MOVES FURTHER EAST...AND THE FRONTS PARENT TROUGH ALOFT TAKES ITS ENERGY EAST AS WELL. LIGHT RAIN AND SNOW SHOWERS WILL LINGER THROUGH THURSDAY AFTERNOON BEFORE FINALLY COMING TO AND END JUST BEFORE 0Z FRIDAY. TEMPERATURES THROUGHOUT THE PERIOD WILL FLUCTUATE QUITE A BIT. TEMPS SUNDAY NIGHT AND MONDAY LOOK TO BE A BIT BELOW NORMAL...WITH LOWS IN THE 30S AND HIGHS IN THE 40S. AFTER ANOTHER COLD NIGHT MONDAY NIGHT...WITH LOWS RANGING FROM THE MID 20S IN OUR NORTH AND THE LOWER 30S IN OUR SOUTH...THE MERCURY IS EXPECTED TO SURGE INTO THE MID TO UPPER 50S BY TUESDAY AFTERNOON. WEDNESDAY LOOKS TO ALMOST AS WARM WITH MOST OF THE AREA LIKELY TO SEE HIGHS IN THE LOW TO MID 50S. AFTER THE COLD FRONT MOVES THROUGH THE AREA WEDNESDAY NIGHT...ANOTHER SURGE OF VERY COLD AIR IS FORECAST TO SETTLE OVER THE AREA. THURSDAY MORNINGS LOWS ARE EXPECTED TO DROP INTO THE LOW TO MID 20S ACROSS MOST OF THE AREA...WITH A FEW LOCATIONS NORTH OF I64 PERHAPS FALLING INTO THE UPPER TEENS. THIS AIR MASS WILL MAKE ITS PRIMARY PUSH INTO THE AREA THURSDAY AND THURSDAY NIGHT...WITH HIGHS ON THURSDAY TOPPING OUT MOSTLY IN THE LOW TO MID 30S. FRIDAY MORNINGS LOWS WILL MARK THE COLDEST TEMPERATURES OF THE UPCOMING WEEK...WITH MINIMUM VALUES RANGING BETWEEN 10 AND 15 DEGREES ACROSS THE AREA. TEMPERATURES WILL ONLY BE SLIGHTLY WARMER FRIDAY AND FRIDAY NIGHT AS WINDS GRADUALLY SHIFT TO WEST AND THEN SOUTHWEST. WE WILL SEE ONLY A SLIGHT IMPROVEMENT IN TEMPERATURES TO END THE WEEK...WITH FORECAST HIGHS ON FRIDAY IN THE MID TO UPPER 30S FOR MOST LOCATIONS...AND OVERNIGHT LOWS AROUND 20. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1253 PM EST SAT FEB 28 2015 MID/HIGH SCT TO BKN CLOUDS ARE BEGINNING TO INTRUDE INTO THE CWA FROM THE WEST AHEAD OF AN APPROACHING BOUNDARY. AS THE AREA OF MOISTURE ASSOCIATED WITH THIS SYSTEM CONTINUES TO NEAR FROM THE WEST...EXPECT CIGS TO GRADUALLY LOWER TO MVFR BY LATE TONIGHT AS LIGHT PRECIP SPREADS ACROSS THE CWA...THEN TO IFR AS PRECIP TAKES HOLD OF THE REGION AND CONTINUES THROUGH THE REMAINDER OF THE TAF PERIOD. THERE IS STILL SOME QUESTION ABOUT THE FREEZING PRECIP POTENTIAL...WITH A WARM LAYER ALOFT...AND SURFACE TEMPS NEAR FREEZING. CONFIDENCE IS HIGH ENOUGH AT THIS TIME THAT IT WAS INCLUDED IN THE TAFS...BUT EXACT TIMING AND IMPACTS ARE STILL YET TO BE PINNED DOWN. LIGHT AND MAINLY VARIABLE WINDS ARE EXPECTED THROUGH MUCH OF TONIGHT AHEAD OF THIS BOUNDARY...INCREASING SLIGHTLY OUT OF THE SOUTH DURING THE DAY TOMORROW. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JMW LONG TERM...AR AVIATION...JMW

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