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000
FXUS63 KJKL 181739
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
139 PM EDT SAT MAY 18 2013

.UPDATE...
ISSUED AT 1111 AM EDT SAT MAY 18 2013

FOG HAS DISSIPATED AND PCPN IS SPARCE WITH THE EXTENSIVE CLOUD COVER.
TEMPS IN LINE SO LITTLE INSTABILITY AND CHANCE FOR ANY THUNDER WILL
BE SLIGHT AND LIMITED TO LATE AFTERNOON. EXPECT PCPN COVERAGE TO
EXPAND WITH WARMER TEMPS IN THE AFTERNOON SO LIKELY POPS STILL A GOOD
CALL. UPDATED GRIDS WITH LATEST OBS AND ZONES TO REMOVE FOG AND
REDUCE POPS...ESPECIALLY THIS MORNING.

UPDATE ISSUED AT 746 AM EDT SAT MAY 18 2013

DIALED DOWN ON THE THUNDER THROUGH THIS MORNING BASED ON THE LATEST
TRENDS IN RADAR. ALSO FRESHENED UP THE HOURLY TEMPERATURES AND DEW
POINTS ACCORDING TO THE CURRENT OBSERVATIONS.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 355 AM EDT SAT MAY 18 2013

THE UPPER LEVEL LOW IS CURRENTLY SPINNING ITS WHEELS NEAR THE TN/KY
LINE IN THE WEST. THE MODELS ARE IN GOOD AGREEMENT THROUGH THE NEXT
36 HOURS...SLOWLY NUDGING THIS FEATURE EASTWARD AND PROVIDING A
CONTINUED FOCUS FOR CONVECTION. POPS HAVE COME IN LIKELY TO
CATEGORICAL FOR TODAY AND SEE NO REASON TO ARGUE. PWATS WILL BE
AROUND 1.5 INCHES AND STORM MOTIONS WILL BE BELOW 10 KTS UNLESS SOME
STORMS BECOME MORE ORGANIZED AND DEVELOP A COLD POOL. WILL CONTINUE
TO MENTION LOCALLY HEAVY RAINFALL AND THE POTENTIAL OF MINOR FLOODING
OF LOW LYING AREAS.

AS THE UPPER LEVEL FEATURE DAMPENS TONIGHT...CONVECTION SHOULD
DIMINISH AT A QUICKER PACE AFTER SUNDOWN. ON SUNDAY...THE BETTER POPS
WILL BE IN THE FAR EAST WITH LESS IN THE WEST. DESPITE THE WEAKER
FORCING...INSTABILITY LOOKS TO BE AMPLE...SO STORM INTERACTION MAY
WIND UP ALLOWING FOR DECENT AREAL COVERAGE BY THE END OF THE DAY.
AGAIN...LOCALLY HEAVY RAIN WILL BE A CONCERN.

FOR TEMPERATURES...STUCK WITH A BLEND OF THE GUIDANCE...WITH HIGHS
RECOVERING TO THE MID 70S TODAY...AND UPPER 70S TO AROUND 80 FOR
SUNDAY.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 425 AM EDT SAT MAY 18 2013

THE PERIOD IS EXPECTED TO BEGIN WITH A WEAKENING UPPER LEVEL
LOW/SHORTWAVE TROUGH DEPARTING TO THE EAST OF THE REGION AND
SHORTWAVE UPPER LEVEL RIDGING WORKING INTO THE LOWER OH VALLEY
REGION. FURTHER WEST...A TROUGH AND CLOSED LOW IS EXPECTED FROM THE
ROCKIES INTO THE PLAINS STATES. THE AXIS OF THE RIDGING IS EXPECTED
TO WORK EAST ACROSS THE REGION ON MON INTO MON EVENING...FOLLOWED BY
SW FLOW ALOFT AHEAD OF THE TROUGH AND CLOSED LOW. A FEW SHORTWAVES
IN THIS SOUTHWEST FLOW ROTATING AROUND THE CLOSED WILL PASS
GENERALLY TO THE WEST OF SOUTH CENTRAL AND EASTERN KY THROUGH
MIDWEEK. EVENTUALLY THIS SYSTEM WILL BEGIN TO OPEN UP A BIT AND
WEAKEN BUT THERE IS CONSIDERABLE UNCERTAINTY AS TO WHETHER OR NOT IS
BECOMES ABSORBED BY AN UPPER LEVEL LOW DROPPING SOUTH INTO ONTARIO
AND QUEBEC LATE IN THE PERIOD PER LATEST ECMWF RUN OR MEANDERS
ACROSS THE OH VALLEY TOWARD THE APPALACHIANS OR MID ATLANTIC STATES
ABOUT A WEEK FROM NOW. AT THE SFC...THE COLD FRONT ASSOCIATED WITH
THE SHORTWAVE TROUGH SHOULD WORK INTO THE REGION LATE IN THE
PERIOD...BUT POSSIBLY NOT EXIT THE CWA BEFORE THE END OF THE PERIOD.

AT THIS POINT...THE FORECAST LEANS A BIT TOWARD THE 0Z ECMWF AND 0Z
GFS FOR TRENDS LATE IN THE PERIOD...BUT THE MODEL CONSENSUS GRID LOAD
WAS GENERALLY FOLLOWED. POPS FROM LATE MON INTO MON NIGHT WERE
LOWERED 10 OR SO PERCENT ON AVERAGE FROM THE GRID LOAD THE RIDGE
SHOULD BRING SOME CAPPING. HOWEVER...EVEN LATE IN THE PERIOD...IF
THE ECMWF VERIFIES THE SFC BOUNDARY WILL BE IN THE VICINITY...AND
THUS CHANCES FOR PRECIP REALLY CANNOT BE RULED OUT COMPLETELY IN ANY
PERIOD. AT THIS POINT THE LOWEST CHANCES APPEAR TO BE FROM LATE
AFTERNOON MONDAY INTO MONDAY NIGHT...AND PERHAPS INTO TUESDAY.

DIURNAL RANGES WILL BE A BIT SUPPRESSED BY ANTICIPATED PERIODIC
CLOUD CLOUD COVER...RELATIVELY WARM AND MOIST AIR MASS IN THE WARM
SECTOR...AND SCATTERED CONVECTION FROM TIME TO TIME. HIGHS WILL
GENERALLY BE IN THE LOW TO MID 80S THROUGH MIDWEEK WITH LOWS IN THE
LOW TO MID 60S. AS THE BOUNDARY AND UPPER SYSTEM WORK ACROSS THE
AREA LATER IN THE PERIOD...HIGHS SHOULD GENERALLY BE IN THE 70S WITH
LOWS IN THE 60S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 140 PM EDT SAT MAY 18 2013

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL PASS ACROSS EASTERN KENTUCKY
THROUGH TODAY...PROVIDING A FOCUS FOR BOUTS OF SHOWERS AND SCATTERED
THUNDERSTORMS. THE COVERAGE WILL BE GREATEST DURING THE AFTERNOON AND
EARLY EVENING HOURS. TEMPORARY IFR OR WORSE CONDITIONS WILL BE
POSSIBLE WITHIN ANY THUNDERSTORMS. THE ADDED MOISTURE WILL PRODUCE
SOME PATCHY IFR FOG IN THE MORNING.

&&

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

$$

UPDATE...DUSTY
SHORT TERM...GEOGERIAN
LONG TERM...JP
AVIATION...DUSTY