Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 181635
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1235 PM EDT MON AUG 18 2014

.UPDATE...
ISSUED AT 1235 PM EDT MON AUG 18 2014

LOW PRESSURE CENTER HAS MOVED EAST INTO WV...AND DEEP MOISTURE AND
BETTER LIFT HAS SHIFTED EAST. QUASI STATIONARY EAST WEST ORIENTED FRONT
REMAINS ACROSS KY AND WILL SERVE AS FOCUS FOR ADDITIONAL SHOWERS. SCATTERED
TO NUMEROUS SHOWERS WILL CONTINUE ACROSS THE FORECAST AREA INTO THE
AFTERNOON...WITH SOME ISOLATED THUNDERSTORMS POSSIBLE BY LATE
AFTERNOON. HAVE UPDATED NDFD TO REMOVE THUNDER FOR THE NEXT SEVERAL
HOURS AND TO ADJUST PROBABILITIES OF RAIN FOR THE REMAINDER OF THE
DAY.

UPDATE ISSUED AT 1010 AM EDT MON AUG 18 2014

ISSUED AN UPDATE TO INPUT THE LATEST OBSERVATIONS. AS WELL...THE BULK
OF THE DEEP MOISTURE HAS ALSO MOVED OFF TO THE EAST. WHILE SOME
SCATTERED SHOWERS THIS AFTERNOON MAY PRODUCE A DECENT SHOWER...THE
OVERALL HEAVY RAINFALL AND FLOODING THREAT HAS DIMINISHED. AS SUCH
HAVE PULLED THE HEAVY RAIN THREAT FROM THE HWO AND SENT UPDATED GRIDS
TO NDFD.

UPDATE ISSUED AT 805 AM EDT MON AUG 18 2014

CURRENT CONDITIONS ACROSS THE AREA FEATURE A SURFACE LOW PRESSURE
SYSTEM CURRENTLY IN CENTRAL KENTUCKY SLOWLY MOVING EAST INTO THE
AREA THIS MORNING. SHOWERS AND A FEW THUNDERSTORMS HAVE BEEN
PRODUCING MODERATE TO HEAVY RAINFALL AT TIMES WITH THE AVAILABLE DEEP
MOISTURE. ACTIVITY THROUGH THE DAY...THOUGH WITH DIMINISHED
INSTABILITY...WILL CONTINUE TO DEVELOP INTO THE AFTERNOON...KEEPING
A MINIMAL BUT STILL PRESENT FLASH FLOOD THREAT. ONE CONCERN IN THE
RECENT RUN OF THE MODELS LIES WITH THE APPROACHING WAVE BEHIND TODAYS
TO IMPACT THE AREA TOMORROW AFTERNOON. WITH DECENT SURFACE BASED
INSTABILITY AND FORCING FROM A COLD FRONT DIVING SOUTHEAST WILL
PROVIDE THE CHANCE FOR A FEW STRONG STORMS ON TUESDAY AFTERNOON AND
INTO THE EVENING...THOUGH MAINLY IN THE NORTHERN COUNTIES.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 315 AM EDT MON AUG 18 2014

FEATURES ACROSS EASTERN KENTUCKY CENTER AROUND A SURFACE LOW PRESSURE
SYSTEM MOVING EAST INTO THE AREA THIS MORNING. SHOWERS AND
THUNDERSTORMS CONTINUE TO DEVELOP AHEAD OF THIS FEATURE IN A WELL
MOIST AND UNSTABLE ENVIRONMENT WITH INSTANCES OF HEAVY RAINFALL
MAINLY OVER THE SOUTHERN PORTIONS OF EASTERN KENTUCKY HEADING INTO
THE MORNING HOURS. THIS BEING WHERE THE BETTER LIFT AND FORCING ALONG
AN APPROACHING SURFACE BOUNDARY. RAINFALL RATES HERE AS WELL AS WHAT
IS ADVERTISED LATER IN THE MORNING AND INTO TODAY WILL FEATURE THE
FLASH FLOODING THREAT MAINLY OVER THESE AREAS SOUTH OF THE MOUNTAIN
PARKWAY. WILL CONTINUE TO MENTION THIS THREAT IN THE HWO AS
THANKFULLY...STORM MOTION IS QUITE QUICK AND RESIDENCE TIME OVER A
CERTAIN LOCATION WILL NOT BE AN ISSUE. HOWEVER...A FEW INSTANCES OF
CELLS MOVING OVER THE SAME LOCATION MAY BE ENOUGH FOR A FLASH FLOOD
THREAT INTO THE PREDAWN HOURS.

LATER ON INTO THIS AFTERNOON...A DRY LAYER BEGINS TO DEVELOP IN THE
MID LEVELS. WITH THE SURFACE INSTABILITY ON THE INCREASE AND STILL
SOME MOISTURE IN THE LOWER LEVELS PRESENT...SOME MORE THUNDERSTORM
DEVELOPMENT WILL BE POSSIBLE WITH LESS MOISTURE DEPTH A CHANCE OF A
STORM THUNDERSTORM OR TWO. WILL CONTINUE WITH AREAL COVERAGE INTO
THIS TONIGHT. WITH THE INCREASE IN STORM MOTION AND LACK OF ABUNDANT
MOISTURE FROM THE PAST DAY...THE FLOODING THREAT WILL BEGIN TO
DIMINISH BY TONIGHT. WILL EXPECT A MORE DIURNALLY DRIVEN THUNDERSTORM
DEVELOPMENT BY TUESDAY AS A WEAK DISTURBANCE FOLLOWS THE PREVIOUS
WAVE ON MONDAY. WILL CONTINUE WITH SCATTERED POPS INTO THIS PERIOD AS
WELL. OVERALL...THE CONCERN LIES WITH THE MESOSCALE FEATURES WITH THE
REMNANT MCV TRACKING THROUGH CENTRAL KENTUCKY AND INTO EASTERN
PORTIONS TODAY WITH A LOCALIZED FLOOD THREAT.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 500 AM EDT MON AUG 18 2014

THE MODELS ARE IN GOOD AGREEMENT ABOUT THE GENERAL PATTERN ALOFT
CONSISTING OF A GREAT LAKES CLOSED LOW EARLY ON BEING SHUNTED
EAST BY A BURGEONING RIDGE OVER THE LOWER MISSISSIPPI VALLEY INTO
THE DAY THURSDAY. THE CMC IS THE FIRST TO DROP OUT AS IT SHOWS A
WEAKER RIDGE THROUGH THE MID SECTION OF THE NATION WHILE THE GFS AND
ECMWF MAINTAIN HIGHER AMPLITUDES ACROSS THE MISSOURI VALLEY AND INTO
THE WESTERN PORTION OF THE OHIO VALLEY TO CLOSE OUT THE WORK WEEK.
THE SIMILARITIES OF THESE LATTER MODELS CONTINUED INTO THE WEEKEND
WITH STRONG RIDGING CENTERED OVER ARKANSAS WHILE BROAD TROUGHING
HOLDS TOUGH THROUGH THE NEW ENGLAND STATES. BETWEEN THESE TWO
FEATURES...A STREAM OF SEASONABLY FAST FLOW WILL CARRY A STEADY
BATCH OF SHORTWAVES FROM THE UPPER MIDWEST THROUGH THE OHIO VALLEY
AND INTO THE SOUTHERN APPALACHIANS. THIS PATTERN REMAINS IN PLACE
THROUGHOUT THE WEEKEND...THOUGH THE CRUCIAL STREAM OF SHORTWAVE
ENERGY WILL LIKELY WAVE BACK AND FORTH THROUGH THE WESTERN FOOTHILLS
OF THE APPALACHIANS. GIVEN THE MODEL AGREEMENT AMONG THE GFS AND
ECMWF HAVE FAVORED THEIR SOLUTION FOR THE EXTENDED PORTION OF THE
FORECAST.

SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR MOIST
ENVIRONMENT AND POTENTIAL FOR SHOWERS AND THUNDERSTORMS. THE RIDGING
TO OUR SOUTHWEST WILL BE ENOUGH TO SEND TEMPERATURES INTO AND ABOVE
SEASONABLE NORMS DESPITE THE INCREASED HUMIDITY. THIS WILL ALSO HELP
TO ENHANCE THE DIURNALLY DRIVEN INSTABILITY THROUGH THE AREA
RESULTING IN THE BEST CHANCES OF STORMS EACH AFTERNOON AND EVENING.
HOWEVER...WITH THE ACTIVITY ALOFT AND THE NEARBY SFC BOUNDARIES THE
THREAT OF CONVECTION WILL CONTINUE THROUGH THE NIGHTS AS WELL. THIS
WILL MEAN A WARM...WET...AND STORMY PERIOD FOR EAST KENTUCKY THROUGH
THE UPCOMING WEEKEND. THE CAVEAT WILL BE SHOULD THE RIDGE TO THE
SOUTHWEST TAKE OVER AND SHIFT JUST A BIT NORTHEAST WE MAY BE IN FOR
A HOT AND HUMID TIME INSTEAD. THIS WILL HAVE TO BE MONITORED...BUT
AS OF NOW THE BEST BET IS FOR A CONTINUATION OF OUR MODERATE CHANCES
FOR SHOWERS AND THUNDERSTORMS THROUGH MOST PERIODS IN THE EXTENDED.
THE HIGH MOISTURE CONTENT WILL HOLD THE TEMPERATURES UP AT NIGHT AND
LIMIT RADIATIONAL COOLING. LIKEWISE...DAYTIME HIGHS COULD BE
IMPACTED BY THE TIMING AND DURATION OF AFTERNOON CONVECTION...BUT
THE POTENTIAL IS THERE FOR READINGS IN THE UPPER 80S EACH DAY.

THE CR GRID LOAD PROVIDED A GOOD START TO THE FORECAST FOR THE
EXTENDED...THOUGH DID GIVE THE POPS MORE OF A DIURNAL TREND.
ALSO...ADJUSTED THE LOW TEMPERATURE GRIDS SLIGHTLY EACH NIGHT TO
REFLECT MINOR RIDGE AND VALLEY DIFFERENCES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 805 AM EDT MON AUG 18 2014

THE BULK OF THE SHOWER AND THUNDERSTORM ACTIVITY HAS MOVED OFF TO THE
EAST BUT A FEW SHOWERS WILL STILL LINGER THROUGH THE MORNING HOURS
BEFORE SOME FURTHER DEVELOPMENT THIS AFTERNOON. OVERALL...SOME LOW
CEILINGS AND VISIBILITY WILL LINGER OVER THE TAF SITES THIS MORNING
BEFORE THEY LIFT AND THE AREA BEGINS TO CLEAR OUT A BIT. WEST WINDS
WILL ALSO ENSURE AN INCREASE IN VISIBILITY AT MOST SITES AS WELL. A
BRIEF PERIOD OF CLEARING TONIGHT WILL ALLOW FOR FOG AND LOW CEILING
DEVELOPMENT BETWEEN WAVES BETWEEN 06Z TONIGHT AND 12Z TOMORROW
MORNING.


&&

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

$$

UPDATE...SBH
SHORT TERM...SHALLENBERGER
LONG TERM...GREIF
AVIATION...SHALLENBERGER






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