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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KJKL 112326
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
726 PM EDT FRI JUL 11 2014

.UPDATE...
ISSUED AT 724 PM EDT FRI JUL 11 2014

MADE A SLIGHT UPDATE TO THE SKY GRIDS FOR TONIGHT AND INTO THE DAY
TOMORROW TO ACCOUNT FOR THE MASS OF HIGH CLOUDS SLOWLY MOVING IN FROM
OUR NE. THIS SHOULD HAVE LITTLE IMPACT TO THE OVERALL FORECAST.
OTHERWISE...JUST LOADED IN THE LATEST OBSERVATIONS FOR TEMPS...DEW
POINTS...AND WINDS. ONGOING FORECAST SEEMS TO BE IN GOOD SHAPE FOR
THE EVENING AND INTO THE OVERNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 255 PM EDT FRI JUL 11 2014

EXPECT ANOTHER MOSTLY CLEAR NIGHT WITH FOG MAINLY CONFINED TO RIVER
AND STREAM VALLEYS. AS HIGH PRESSURE SHIFTS EAST AND LOW LEVEL FLOW
BECOMES MORE SSW ON SATURDAY WE WILL SEE A SLIGHT INCREASE IN
DEWPOINTS AND TEMPERATURES FOR SATURDAY AFTERNOON WHEN COMPARED TO
TODAY. HOWEVER WITH DEWPOINTS ONLY EXPECTED TO BE AROUND 60 SATURDAY
AFTERNOON IT WILL STILL NOT BE AS HUMID AS IT COULD BE THIS TIME OF
YEAR. IT WILL ALSO BE WARMER SATURDAY NIGHT WITH LOWS AROUND 5 DEGREES
WARMER THAN TONIGHT. DRY WEATHER IS EXPECTED TO CONTINUE THROUGH
SATURDAY NIGHT WITH ANY PRECIPITATION CHANCES REMAINING NORTHWEST AND
SOUTHEAST OF THE FORECAST AREA.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 255 PM EDT FRI JUL 11 2014

AFTER A PERIOD OF GOOD AGREEMENT IN EXTENDED SOLUTIONS...THE 12Z GFS
HAS TAKEN A SUDDEN TURN FROM PREVIOUS RUNS AND THE GENERAL CONSENSUS
OF MODEL SOLUTIONS AS EARLY AS 24 HOURS INTO THE EXTENDED. THIS
CLOUDS UP MUCH OF THE DETAILS SURROUNDING THE MAJOR STORM SYSTEM
POISED TO AFFECT A LARGE PORTION OF THE CENTRAL CONUS NEXT WEEK.
INITIAL THOUGHTS ARE THAT IT SEEMS LIKE THE GFS IS HAVING TROUBLE
RESOLVING THE TIMING OR PASSAGE OF A COLD FRONT THAT SHOULD DROP
SOUTHWARD INTO THE REGION LATE SUNDAY INTO MONDAY FROM A SECONDARY
SURFACE TROUGH OR FRONT THAT DROPS THROUGH THE AREA BY LATE TUESDAY.
OVERALL TRENDS ARE THAT MODELS APPEAR TO HAVE TRENDED SLIGHTLY
SLOWER WITH THE BOUNDARY ON TUESDAY OVER THE LAST COUPLE OF RUNS...
WITH PASSAGE THROUGH EASTERN KENTUCKY FALLING BACK FROM MOVING FROM
EARLY TUESDAY TO LATER IN THE DAY TUESDAY.

THIS MAY PLAY A ROLE IN THE POTENTIAL OF SEVERE WEATHER BY EARLY
NEXT WEEK AS WELL. AT PRESENT BULK SHEAR APPEARS MARGINAL FOR SEVERE
WEATHER. BUT DYNAMICS COMBINED WITH THE SPEED OF THE LARGE SCALE
FEATURES DRIVING THESE SYSTEMS AND CONTRASTING AIR MASSES MAY BE
ENOUGH TO OVERCOME THE MARGINAL LEVELS OF BULK SHEAR REQUIRED FOR A
ROUND OF SEVERE WEATHER. CONSEQUENTLY SPC HAS PLACE OUR AREA IN A
DY4 RISK FOR SEVERE WEATHER...MONDAY INTO TUESDAY.

TO START THE EXTENDED...PARENT UPPER LEVEL LOW JUST SOUTHWEST OF
HUDSON BAY WILL BE RESPONSIBLE FOR A LARGE BROAD TROUGH ACROSS
CENTRAL CANADA EXTENDING SOUTHEASTWARD INTO THE UPPER MIDWEST...
GREAT LAKES AND OHIO VALLEY REGIONS. FAST MOVING SHORT WAVE RIPPLE
WILL TRANSIT THE SOUTHERN END OF THE TROUGH...ALLOWING A SFC COLD
FRONTAL BOUNDARY TO DROP SOUTHWARD TOWARDS THE OHIO RIVER SUNDAY.
THEREAFTER...THE UPSTREAM UPPER LEVEL LOW SPLITS OVER CANADA AND A
SIGNIFICANT PORTION OF THE ENERGY DIVES QUICKLY SOUTHWARD INTO INTO
THE UPPER MIDWEST AND GREAT LAKES...RESULTING IN A LARGE DEEP TROUGH
ACROSS THE ENTIRE EASTERN CONUS BY TUE/WED. THIS WOULD ENSURE THE
INVASION OF UNSEASONABLY COLD WEATHER INTO THE HEART OF THE CONUS
DURING THE PEAK OF SUMMER HEATING. FROM ALL APPEARANCES...THIS
SYSTEM WILL ADVANCE ALL THE WAY TO THE GULF COAST TOWARDS THE END OF
THE WEEK. TRENDS ARE THAT TEMPERATURES WILL MODERATE ONLY SLOWLY
THROUGH THE REMAINDER OF THE WEEK. IN ADDITION...THIS MAY ESTABLISH
A BAROCLINIC ZONE JUST TO OUR SOUTH SETTING THE STAGE FOR THE
POTENTIAL OF ADDITIONAL UNSETTLED WEATHER AT THE END OF THE EXTENDED
WINDOW AND JUST BEYOND AS A COUPLE OF WEAK SOUTHERLY TRACKING
SYSTEMS MOVE WEST TO EAST ACROSS THE TN VALLEY AND DEEP SOUTH.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 726 PM EDT FRI JUL 11 2014

OVERNIGHT DEVELOPMENT OF FOG SHOULD BE SIMILAR IN EXTENT...DURATION AND
ASSOCIATED VISIBILITIES TO LAST NIGHT. MOST FOG WILL BE CONFINED TO
RIVER VALLEYS AND SHOULD ONLY RESULT IN A COUPLE OF HOURS OF MVFR
VISIBILITY AT LOZ...SME AND SJS EARLY TOMORROW MORNING. OTHERWISE
VFR CONDITIONS AND LIGHT WINDS WILL PERSIST ACROSS THE AREA.

.JKL WATCHES/WARNINGS/ADVISORIES...

&&

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

$$

UPDATE...JMW
SHORT TERM...SBH
LONG TERM...RAY
AVIATION...JMW