Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 270228
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1028 PM EDT SUN OCT 26 2014

.UPDATE...
ISSUED AT 1028 PM EDT SUN OCT 26 2014

UPDATED THE FORECAST TO BETTER REFLECT THE CURRENT CONDITIONS AND
MODEL TRENDS. AS PREDICTED EARLIER...TEMPERATURES WERE GOING TO BE
DIFFICULT TONIGHT. MADE SOME ADJUSTMENTS BASED MAINLY ON
EXTRAPOLATION AND THE NORMAL NOCTURNAL TEMPERATURE CURVE. IF ANY
OF THE LOCATIONS MIX OUT...THE TEMPERATURE COULD JUMP OVER 10 DEGREES.
SINCE THE WIND HAS BEEN SO LIGHT...CURRENT THINKING IS THAT THEY WILL
NOT MIX OUT AND A NORMAL NOCTURNAL DROP WILL BE EXPECTED.

UPDATE ISSUED AT 741 PM EDT SUN OCT 26 2014

UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. TEMPERATURES ARE GOING TO BE A BIT TRICKY TONIGHT AS SOME OF
THE VALLEYS WILL DECOUPLE BEFORE MOISTURE IS ABLE TO ADVECT INTO
THEM. THIS WILL ALLOW THE TEMPS TO DROP FURTHER IN THOSE VALLEYS THAT
DECOUPLE FIRST.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 335 PM EDT SUN OCT 26 2014

MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM. TRANSITING MID
AND UPPER LEVEL SHORT WAVE RIDGING WILL KEEP OUR WEATHER DRY THROUGH
THE PERIOD. BUT UPPER LEVEL WINDS BECOME MORE SOUTHWESTERLY DURING
THE LAST 12 TO 18 HOURS AS OUR NEXT WEATHER MAKER APPROACHES. AT THE
SFC HIGH PRESSURE MOVES OFF TO THE EAST THIS EVENING ALLOWING RETURN
SOUTHERLY FLOW TO KICK IN. A WEAK SFC BOUNDARY APPEARS TO MOVE
THROUGH THE AREA FROM SOUTHWEST TO NORTHEAST DURING THE OVERNIGHT
WHICH WILL USHER IN A WARMER AND MORE MOIST AIR MASS. THIS FEATURE
WILL MAKE OVERNIGHT LOW TEMPERATURES AND FOG POTENTIAL A CHALLENGE.
FOR NOW HAVE DECIDED TO FOLLOW MODEL GUIDANCE CLOSELY DUE TO GOOD
AGREEMENT. BUT AFTER SEEING GUIDANCE PERFORMANCE SO FAR THIS
AFTERNOON...THOUGHTS ARE THAT MODELS ARE NOT HANDLING THINGS WELL
AND MAY NOT BE HANDLING THE TRANSITION OF WARMER AIR BACK INTO THE
AREA PROPERLY...ESPECIALLY ONCE THE NOCTURNAL INVERSION SETS UP.
BOTTOM LINE IS THAT OVERNIGHT LOWS MAY NOT BE LOW ENOUGH IN THE
EASTERN VALLEYS AND FOG MAY BE MORE PREVALENT ACROSS THE FORECAST
AREA TONIGHT THAN MODELS WOULD SUGGEST. WILL PASS ON CONCERNS TO
EVENING SHIFT TO MONITOR. OTHERWISE WE WARM UP QUITE NICELY TOMORROW
FOR ONE OF THE WARMEST DAYS WE HAVE HAD IN AWHILE. ENJOY IT WHILE
YOU CAN BECAUSE BIG CHANGES ARE SHOWING UP OVER THE HORIZON.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 456 PM EDT SUN OCT 26 2014

TWO SYSTEMS TO CONTEND WITH DURING THIS PERIOD. MODELS ARE IN
REASONABLE AGREEMENT FOR THE FIRST ONE...A COLD FRONT APPROACHING AND
MOVING THROUGH TUESDAY AND TUESDAY NIGHT. WARM AIR ADVECTION WILL BE
ONGOING TUESDAY AHEAD OF THE FRONT. WITH SOME SUNSHINE BEFORE THE
FRONT NEARS...EXCEPTIONALLY WARM TEMPS BY LATE OCTOBER STANDARDS WILL
OCCUR AGAIN. MODELS ARE COMING INTO BETTER AGREEMENT ON TIMING...BUT
STILL SHOW THE LEADING AND TRAILING EDGES OF THE PRECIP IN THE JKL
FORECAST AREA AT 00Z TUESDAY EVENING. THIS MAKES THE 12HR POP FOR DAY
VERSUS NIGHT TRICKY. THINK THAT MOST PLACES WILL SEE PRECIP FROM THE
SYSTEM...JUST A MATTER OF WHETHER IT OCCURS DURING THE DAY OR NIGHT.
WEAK INSTABILITY IS STILL INDICATED IN MODELS...AND A SLIGHT CHANCE
OF THUNDER IS AGAIN INCLUDED. PRECIP SHOULD EXIT SE OUT OF THE AREA
TUESDAY NIGHT OR EARLY WEDNESDAY...AND SURFACE HIGH PRESSURE WILL
BUILD IN FROM THE WEST TO PROVIDE FAIR WX AND TEMPS FALLING BACK TO
NEAR NORMAL AT MIDWEEK.

THE NEXT SYSTEM WILL AFFECT THE REGION AT THE END OF THE WEEK...WITH
A DEEP MID/UPPER LEVEL TROUGH EXPECTED TO DEVELOP OVER THE EASTERN
CONUS. MODELS ARE STILL TRYING TO HONE IN ON HOW THE SYSTEM PLAYS
OUT...AND ARE STILL SHOWING A CONSIDERABLE AMOUNT OF VARIABILITY RUN
TO RUN AND MODEL TO MODEL. THERE DOES SEEM TO BE AGREEMENT ON A VERY
CHILLY AIR MASS ARRIVING AT THE END OF THE WEEK...PROBABLY ON FRIDAY
AND FRIDAY NIGHT. THIS WILL LIKELY BRING AND END TO THE GROWING
SEASON BY SUNDAY MORNING IN MOST IF NOT ALL PLACES WHERE IT HAS NOT
ENDED YET. IN TERMS OF MODEL DIFFERENCES...THE VARIATIONS IN
EVOLUTION OF THE STORM SYSTEM HAVE RAMIFICATIONS FOR PRECIP IN OUR
AREA. SOME MODEL RUNS SHOW A POTENTIAL FOR SNOW SHOWERS LATE FRIDAY
NIGHT...ESPECIALLY FOR OUR HIGHER ELEVATIONS...AND LOW POPS FOR THIS
ARE IN THE FORECAST.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 741 PM EDT SUN OCT 26 2014

VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD.  RETURN FLOW
WILL BE DEVELOPING OVERNIGHT TO USHER IN A WARMER...MORE MOIST AIR
MASS FROM THE SOUTH. AS A RESULT WINDS WILL BECOME MORE SOUTHERLY
WITH TIME AND INCREASE TO AROUND 5-8 KTS BY MONDAY AS ANOTHER STORM
SYSTEM DEVELOPS TO OUR WEST. THE FOG IS GOING TO BE A BIT TRICKY
TONIGHT AS SOME OF THE VALLEYS WILL DECOUPLE BEFORE MOISTURE IS ABLE
TO ADVECT INTO THEM. THIS WILL ALLOW THE TEMPS TO DROP FURTHER IN
THOSE VALLEYS THAT DECOUPLE FIRST. WITH THE DRIER AIR IN THOSE
VALLEYS...THE FOG WILL ALSO BE MORE DIFFICULT TO FORM. SO EXPECT A
MIXTURE OF SOME VALLEYS WITH VLIFR AND SOME MVFR. THE TAF STATIONS
SHOULD STAY VFR.


&&

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

$$

UPDATE...JJ
SHORT TERM...RAY
LONG TERM...HAL
AVIATION...JJ






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