Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 010604
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
204 AM EDT WED OCT 1 2014

.UPDATE...
ISSUED AT 204 AM EDT WED OCT 1 2014

BACK DOOR COLD FRONT IS DROPPING FARTHER SOUTHWEST THAN EXPECTED WITH
LIGHT NORTHEAST WINDS DEVELOPING. THE STRATUS TO OUR NORTH HAS BEGUN
TO EXPAND JUST BEHIND THE FRONT AND IS WORKING SOUTH INTO NORTHEAST
KENTUCKY. GIVEN THE NORTHEAST WINDS...THIS PROGRESSION SHOULD
CONTINUE. WITH THIS IN MIND...TEMPERATURES MAY STAY A BIT HIGHER
TONIGHT THAN PREVIOUS FORECAST. IN ADDITION...FOG IS LOOKING LIKE A
LESSER THREAT WITH CONDITIONS FAVORING MORE STRATUS. THUS...WILL
UPDATE TO DOWNPLAY FOG INCLUDING REMOVING IT FROM THE HWO. ALL
FORECAST CHANGES HAVE BEEN SAVED AND SENT.

UPDATE ISSUED AT 1002 PM EDT TUE SEP 30 2014

BASED ON THE LATEST TEMPERATURE AND DEW POINT TRENDS...THE LATEST
GUIDANCE...AND COMPARISONS IN TEMPERATURES...DEW POINTS...AND
FOG/CLOUDS TO THAT OF LAST NIGHT...DECIDED TO ADJUST THE OVERNIGHT
LOWS FOR TONIGHT/TOMORROW MORNING SOMEWHAT ACROSS THE CWA.
OVERALL...TRENDED DOWN SEVERAL DEGREES FROM PREVIOUS FORECAST...WITH
LOWER DEW POINTS EARLIER IN THE AFTERNOON AND SLIGHTLY LESS FOG
POTENTIAL OVERNIGHT EXPECTED TO PLAY A FACTOR IN ALLOWING TEMPS TO
DROP SEVERAL DEGREES LOWER THAN THAT OF LAST NIGHT.

UPDATE ISSUED AT 804 PM EDT TUE SEP 30 2014

FORECAST SEEMS TO BE FAIRLY WELL IN SHAPE SO FAR THIS EVENING.
UPDATED THE NEAR TERM GRIDS WITH THE LATEST OBSERVATIONAL DATA FOR
TEMPS...DEW POINTS AND WINDS. WILL CONTINUE TO MONITOR THESE
PARAMETERS AS WE HEAD LATER INTO THE EVENING/OVERNIGHT TO BETTER
ASSESS THE FOG POTENTIAL.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 255 PM EDT TUE SEP 30 2014

THE FORECAST MODELS WERE ALL IN VERY GOOD AGREEMENT REGARDING THE
WEATHER PATTERN FOR THE NEXT FEW DAYS. A WELL DEVELOPED RIDGE OF HIGH
PRESSURE ALOFT WILL REMAIN IN PLACE OVER THE GREAT LAKES...OHIO
VALLEY AND TENNESSEE VALLEY REGIONS OVER THE NEXT 36 HOURS. THE
RESULT WILL BE LIGHT AND VARIABLE WINDS...MOSTLY CLEAR SKIES...AND
DRY WEATHER. TEMPERATURES DURING THIS TIME WILL BE ABOVE NORMAL FOR
THE TIME OF YEAR DUE TO THE INFLUENCE OF THE HIGH PRESSURE AND THE
ABUNDANT SUNSHINE THAT WILL BATH THE REGION. HIGHS ON WEDNESDAY WILL
BE TOPPING OUT IN THE UPPER 70S AND LOWER 80S...WITH OVERNIGHT LOWS
TONIGHT AND TOMORROW NIGHT DROPPING INTO THE LOW TO MID 50S FOR MOST
LOCATIONS. THE WEATHER ISSUE OF NOTE THE NEXT COUPLE OF NIGHTS WILL
FOG. CONDITIONS REMAIN PRIMED FOR ANOTHER NIGHT OR TWO OF WIDESPREAD
FOG. BASED ON THE LATEST TIME HEIGHT CROSS SECTIONS AND MODEL
SOUNDINGS...AND PREVAILING CONDITIONS...THE FOG WILL LIKELY BECOME
DENSE AGAIN FOR A LARGE PORTION OF THE AREA. UPCOMING SHIFTS WILL
NEED TO MONITOR THE SITUATION TO DETERMINE IF ANY PRODUCTS NEED TO BE
ISSUED TO DEAL WITH THE FOG.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 255 PM EDT TUE SEP 30 2014

AT THE MID AND UPPER LEVELS MODELS ARE IN REASONABLE AGREEMENT WITH
LARGE SCALE FEATURES. SHORT WAVE RIDGING IN PLACE OVER THE OHIO
VALLEY AT THE START OF THE EXTENDED WILL RAPIDLY YIELD TO A LARGE
TROUGH AND LOW PRESSURE SYSTEM THAT IS EXPECTED TO BULL DOZE ITS WAY
INTO THE EASTERN CONUS BY LATE FRIDAY...SATURDAY. THIS SYSTEM WILL
PROVIDE OUR AREA WITH A SOLID SHOT OF COLDER AUTUMN LIKE AIR AND
DOMINATE OUR WEATHER PATTERN THROUGH THE REMAINDER OF THE EXTENDED.
CHALLENGE WILL CENTER AROUND SHORT WAVE ACTIVITY THAT ROUNDS THE
BOTTOM OF THE LARGER EASTERN CONUS TROUGH THROUGH THE REMAINDER OF
THE EXTENDED...OR MORE SPECIFICALLY THE TIMING OF THESE IMPULSES
THROUGH OUR AREA.

SENSIBLE WEATHER WILL FOCUS MAINLY AROUND STRONG COLD FRONTAL SYSTEM
THAT WILL SWEEP ACROSS MUCH OF THE EASTERN CONUS...AND THROUGH THE
OHIO VALLEY FRIDAY. A FEW IMPULSES BEHIND THIS FIRST SYSTEM WILL
SERVE MAINLY TO REINFORCE THE MUCH COOLER AIR THAT WILL SETTLE OVER
THE FORECAST AREA THROUGH THE BULK OF THE EXTENDED. A FAST MOVING
COLD FRONT WILL PRODUCE SHOWERS AND A CHANCE OF THUNDERSTORMS
FRIDAY. SHOULD FORECAST SOUNDINGS BE REALIZED AND IN PARTICULAR
SOMETHING SIMILAR TO THE 12Z GFS SOLUTION...THERE COULD BE A
POTENTIAL FOR A FEW STRONGER THUNDERSTORMS AS THE COLD FRONT PUSHES
ITS WAY ACROSS OUR FORECAST AREA. WITH H850 LLJ APPROACHING 50 KTS
COMBINED WITH SFC BASED INSTABILITY DIRECTLY AHEAD OF THE FRONT...
LIS OF -3/CAPES ABOUT 1000 J/KG...THOUGHTS ARE THAT SOME STRONGER
WINDS MAY MIX DOWN TO THE SFC IN AND NEAR ANY THUNDERSTORMS. WITH
SHEAR PROFILES SHOWING THE MAJORITY OF THE BULK SHEAR EXISTING IN
THE LOWER 3 KM OF THE SOUNDING...THE POTENTIAL FOR SOME BOWING
CELLS/LINE SEGMENTS CAN NOT BE RULED OUT. HOWEVER...GREATER SFC
BASED INSTABILITY WOULD BE REQUIRED FOR ANY SIGNIFICANT SEVERE
THREAT. WINDS WILL BECOME GUSTY BEHIND THE FRONT AS WELL...AS COLDER
AIR COMES RUSHING IN LATE FRIDAY. WITH STRONG MIXING THESE GUSTY
WINDS APPEAR TO LINGER INTO FRIDAY NIGHT....EARLY SATURDAY MORNING
BEFORE SUBSIDING. TEMPERATURES WILL COOL CONSIDERABLY. HIGHS WILL
LIKELY ONLY CLIMB INTO THE 50S SATURDAY AND ONLY GRADUALLY MODERATE
FROM THERE AS REINFORCING SHOTS OF COOLER AIR WORK THERE WAY INTO
THE REGION FROM TIME TO TIME...THE NEXT MOST IMMEDIATE BEING A FRONT
THAT MOVES ACROSS THE CWA MONDAY.

GIVEN THAT THE MODELS CONTINUE TO ADVERTISE A THEME OF THE GFS BEING
WARMER AND THE ECMWF MUCH COLDER FROM SAT THROUGH THE END OF THE
PERIOD...THE BLEND OF GUIDANCE SEEMED TO BE THE BEST COURSE OF
ACTION AT THIS TIME. HOWEVER...THE WARMER GFS IS TRENDING TOWARDS
THE COOLER ECMWF OVERALL. THE BOTTOM LINE IS THE PERIOD BEGINS MILD
AND THEN ENDS WITH BELOW NORMAL TEMPERATURES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 204 AM EDT WED OCT 1 2014

A BACK DOOR COLD FRONT IS PUSHING SOUTHWEST INTO EASTERN KENTUCKY
WITH A SHALLOW STRATUS DECK BUILDING SOUTH BEHIND IT. THIS
PROGRESSION SOUTHWARD SHOULD CONTINUE THROUGH THE REMAINDER OF THE
NIGHT WITH AREAS CLOUDING OVER WITH AN IFR/MVFR LAYER OF CLOUDS. THIS
SHOULD LIMIT THE OVERALL FOG THREAT...WHILE...STILL POSING AVIATION
CONCERNS. GIVEN MODELS POOR HANDLING OF THE STRATUS...CONFIDENCE
REMAINS LOW ON HOW LONG IT WILL PERSIST INTO THE MORNING. SAFE TO
SAY...IT MAY TAKE UNTIL MID MORNING BEFORE WE SEE CONDITIONS GO BACK
TO VFR. SHOULD STILL SEE AT LEAST SOME PATCHY RIVER VALLEY FOG...BUT
SHOULD BE MORE LIMITED THAN LAST NIGHT GIVEN THE INCREASING CLOUDS.
AFTER THE STRATUS BURNS OFF TOMORROW...REMAINDER OF THE PERIOD SHOULD
FEATURE VFR CONDITIONS.

&&

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

$$

UPDATE...KAS
SHORT TERM...AR
LONG TERM...RAY
AVIATION...KAS





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