Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 240750 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
350 AM EDT THU JUL 24 2014

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EDT THU JUL 24 2014

06Z SFC ANALYSIS SHOWS A WEAK AREA OF LOW PRESSURE OVER EAST KENTUCKY
ALONG A COLD FRONT THAT IS GRADUALLY SETTLING THROUGH THE CWA. THIS
BOUNDARY AND LOW IS RESPONSIBLE FOR THE SHOWERS AND STORMS WE SAW
EARLIER IN THE EVENING AND THE ONES THAT STILL LINGER OVER NORTH
CENTRAL KENTUCKY. NORTHWEST OF THIS FRONT...A COOL AND DRY AREA OF
HIGH PRESSURE IS IN PLACE OVER THE MIDWEST ON FINAL APPROACH TO EAST
KENTUCKY...SCHEDULED TO ARRIVE BY THURSDAY EVENING. MEANWHILE...
SCATTERED SHOWERS AND STORMS WILL REMAIN A THREAT THROUGH THE REST OF
THE MORNING AND INTO THE START OF THURSDAY. PATCHY FOG AND PLENTY OF
LOW CLOUDS ARE FOUND THROUGH EAST KENTUCKY AT THE MOMENT...AS WELL.
THIS ALL IS EXPECTED TO LINGER THROUGH SUNRISE AS TEMPERATURES AND
DEWPOINTS STAY ABOUT WHERE THEY ARE CURRENTLY...IN THE UPPER 60S AND
LOWER 70S. SIMILARLY...THE WINDS WILL REMAIN LIGHT AND VARIABLE WELL
INTO THE DAY THURSDAY.

THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THEY
ALL SHIFT THE EASTERN TROUGH SLIGHTLY NORTHEAST IN RESPONSE TO A
FLATTENING OF THE STRONG WESTERN RIDGE. LEADING OFF THIS TRANSITION
ARE A COUPLE OF SHORTWAVES THAT WILL CROSS THE SOUTHERN OHIO VALLEY
AND KENTUCKY INTO THE AFTERNOON THURSDAY. RISING HEIGHTS WILL FOLLOW
LATER TONIGHT  AND THROUGH THE DAY FRIDAY HELPING TO KEEP ANY ENERGY
PACKETS IN THE NORTHWEST FLOW FROM AMOUNTING TO MUCH OVER OUR AREA.
WITH THE MODEL AGREEMENT HAVE FAVORED THE HRRR AND NAM12 SOLUTIONS
FOR THE FORECAST TODAY AND THEN A GENERAL MODEL BLEND INTO FRIDAY. OF
NOTE...BOTH THE NAM12 AND THE ECMWF DO MAKE MORE OUT OF A BAND OF
PCPN THAT THEY FORECAST TO ACCOMPANY THE COLD FRONT AS IT EXITS LATER
TODAY...IN COMPARISON TO THAN THE GFS AND GEM.

SENSIBLE WEATHER WILL FEATURE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS SLOWLY EXITING EAST KENTUCKY AS A SFC WAVE AND COLD
FRONT DEPARTS TO THE SOUTHEAST BY LATE AFTERNOON. COOLER AIR WITH
THIS BOUNDARY...LOW CLOUDS...AND THE PCPN WILL KEEP TEMPERATURES ONLY
IN THE 70S TODAY. HIGH PRESSURE THEN SETTLES INTO THE AREA TONIGHT
WITH DRIER AIR AND EVEN COOLER TEMPERATURES. THE MAIN QUESTION FOR
TONIGHT WILL BE HOW MUCH CLOUD COVER WILL REMAIN OVER EAST KENTUCKY
IN THE WAKE OF THE FRONT. THE TIME SECTIONS FROM THE NAM12 SUGGEST
THAT LOW CLOUDS WILL BE TOUGH TO CLEAR THROUGH DAWN SO HAVE GONE
CLOUDIER WITH THE GRIDS...WITH LIMITED RADIATIONAL COOLING AND FOG
ANTICIPATED FOR THIS REASON. THESE CLOUDS SHOULD START TO BREAK UP
MORE EFFECTIVELY ON FRIDAY ALLOWING FOR A WARMUP BACK INTO THE LOW
80S...ALONG WITH PLEASANT HUMIDITY LEVELS.

HAVE USED THE CONSSHORT AS A STARTING POINT FOR TEMPERATURES...
DEWPOINTS...AND WINDS THROUGH THE FIRST 24 HOURS AND THEN THE CONSALL
THEREAFTER. AS FOR POPS...HAVE ENDED UP ON THE HIGH SIDE OF THE MOS
NUMBERS...CLOSER TO THE MET...TODAY WITH LOW POPS TONIGHT AND
FRIDAY...IN LINE WITH THE GUIDANCE.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM EDT THU JUL 24 2014

THE EXTENDED PORTION OF THE FORECAST BEGINS ON FRIDAY NIGHT WITH A
CONTINUED AND PRONOUNCED RIDGE OVER THE WEST AND DEEPENING TROUGH
OVER THE EASTERN CONUS. BOTH THE GFS AND EURO HINT AT A POSSIBLE
WEAKENING MCS TRAVERSING OVER THE RIDGE AND THROUGH THE UPPER MS
RIVER VALLEY AND INTO THE OH VALLEY ON FRIDAY NIGHT. FOLLOWING THIS
WILL BE A STRONG SHORT WAVE MOVING SOUTHEAST FROM MN AND INTO THE OH
VALLEY BY SUNDAY AND SUNDAY NIGHT. AS THIS WAVE SWINGS THROUGH THE
BASE OF THE TROUGH...A 90 KNOT JET MAX WILL PUSH THROUGH DEEPENING
THE LONG WAVE TROUGH OVER THE EASTERN CONUS AND KEEPING THE QUITE
AMPLIFIED TROUGH IN PLACE THROUGH THE REST OF THE EXTENDED. IN
RESPONSE...THE WESTERN RIDGE INCREASES IN STRENGTH KEEPING A RARE
MERIDIONAL PATTERN IN PLACE FOR THIS TIME OF YEAR. WITH THE MODELS
SHOWING SOME AGREEMENT IN THIS TREND IT CAN BE SAFE TO SHOW A HIGH
LEVEL OF CONFIDENCE WITH THE ALL MODEL BLEND SOLUTION.

FOR SOME MORE DETAILS IN THE LOWER LEVELS...THE MODELS SEEM TO BE IN
AGREEMENT WITH THE DECAYING MCS MAKING IT INTO THE AREA FRIDAY
NIGHT. THIS SHOULD ERODE THE ADVERTISED CAP THROUGH FRIDAY NIGHT AND
ALLOW SOME ADDITIONAL DEVELOPMENT INTO THE DAY ON SATURDAY WITH
DECENT INSTABILITY AVAILABLE AND SOME UPPER LEVEL SUPPORT ARRIVING
AHEAD OF A POTENT SHORTWAVE. THE BEST CHANCE FOR SHOWER AND
THUNDERSTORM DEVELOPMENT WILL COME ON SUNDAY AND INTO MONDAY WITH A
STRONG COLD FRONT MOVING THROUGH. WENT WITH THE LIKELY POPS
INHERITED FROM THE ALL MODEL BLEND. AT AN EARLY LOOK TO THIS
SCENARIO...QUITE A BIT OF DYNAMICS ARE WITH THIS FEATURE WITH THE
STRONG JET STREAK MOVING THROUGH THE OH VALLEY AND AFTERNOON CAPE
VALUES REACHING 2500 J/KG...A SEVERE WEATHER THREAT IS CERTAINLY NOT
OUT OF THE QUESTION IF THE STRENGTH OF THE WAVE HOLDS TRUE THROUGH
THE DAYS LEADING UP TO THE EVENT. THIS WILL BE THE REAL FORECAST
CHALLENGE AS THE POTENTIAL IS THERE...BUT WILL HAVE TO SEE HOW THE
MODELS TREND UP TO THE EVENT. A COUPLE WEAK DISTURBANCES WILL FOLLOW
BEHIND THIS WAVE AND WILL PROVIDE A LOW CHANCE FOR PRECIP INTO
TUESDAY BEFORE HIGH PRESSURE SETTLES IN FOR THE REST OF THE
EXTENDED. THE AIR MASS MOVING IN BEHIND THIS FRONT IS QUITE COOL
WITH HIGH TEMPERATURES FOR MONDAY THROUGH WEDNESDAY IN THE MID
70S...AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. MODEL
TRENDS WOULD SUGGEST THAT AN OVERALL COOLER PATTERN FOR THE LAST
WEEK OF JULY WILL BE THE CASE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 155 AM EDT THU JUL 24 2014

SCATTERED SHOWERS AND THE ODD THUNDERSTORM WILL CONTINUE TO DIMINISH
FOR THE BULK OF THE FORECAST AREA THROUGH THE NIGHT. HOWEVER...A
COUPLE OF CELLS WILL STILL BE POSSIBLE INTO DAWN...BUT PROBABLY KEEP
FROM HITTING ANY OF THE ACTUAL TAF SITES. FOR THE MOST PART...
CONDITIONS WILL BE MVFR AT ALL THE AIRPORTS TONIGHT WITH TIMES OF VFR
BUT ALSO LOW VIS/CIG INDUCED IFR WX...OR LOWER. HAVE KEPT THUNDER AND
EVEN VCTS OUT OF THE TAFS AS THE INSTABILITY WILL BE MINIMAL
THROUGH THE REST OF THE NIGHT INTO THURSDAY. HOWEVER...THE LATEST
HRRR AND NAM12 SUGGEST THAT A FEW SHOWERS WILL STILL BE POSSIBLE INTO
THE AFTERNOON AS THE FRONT MAKES ITS FINAL PUSH ACROSS THE AREA.
HAVE CONTINUED A VCSH FOR THIS IN ALL SITES WITH CIGS GENERALLY AROUND
2K FEET. IN THE WAKE OF THE FRONT LATER THURSDAY EVENING...DRIER AIR
IS EXPECTED TO LIFT THE CIGS AND REMOVE THE THREAT OF SHOWERS. WINDS
THROUGH THE PERIOD WILL BE MAINLY LIGHT AND VARIABLE...THOUGH
FAVORING THE NORTHERLY DIRECTION LATER THURSDAY.

&&

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

$$

SHORT TERM...GREIF
LONG TERM...SHALLENBERGER
AVIATION...GREIF



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