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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KJKL 150540
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
140 AM EDT WED MAY 15 2013

.UPDATE...
ISSUED AT 105 AM EDT WED MAY 15 2013

NO UPDATE TO THE ZONES THIS MORNING. FORECAST...GRIDS ARE IN
EXCELLENT SHAPE. ONLY MINOR TWEAKS WERE MADE TO HOURLY GRIDS.

UPDATE ISSUED AT 1045 PM EDT TUE MAY 14 2013

HOURLY TEMPS...DEW POINTS AND WINDS WERE FRESHENED UP BASED ON THE
MOST RECENT OBSERVATION DATA. A RIDGE/VALLEY SPLIT HAS ALREADY
DEVELOPED WITH SOME OF THE SOUTHEASTERN VALLEY LOCATIONS HAVING
ALREADY REACHED THE MID TO UPPER 50S PER KY MESONET...CWOP AND MADIS
DATA. THIS TREND SHOULD CONTINUE OVERNIGHT AND THE PREVIOUSLY
FORECAST MIN TEMPS STILL APPEAR REACHABLE. THE COLDEST SPOTS MIGHT
DROP AS LOW AS 49 OR 50 PENDING MIXING AS WINDS MIGHT PICK UP AT
TIMES WITH PRESS GRADIENT FORECAST TO INCREASE.

UPDATE ISSUED AT 802 PM EDT TUE MAY 14 2013

HOURLY GRIDS WERE FRESHENED UP BASED ON RECENT TRENDS. SOME AC IS
CURRENTLY WORKING OVERHEAD. WITH A WARM FRONT HAVING PASSED THROUGH
THE REGION TODAY...THE AREA IS CURRENTLY IN THE WARM SECTOR WITH
DEW POINTS IN SOME CASES AROUND 20 DEGREES HIGHER THAN AT THIS POINT
24 HOURS AGO. IN ADDITION...A RELATIVELY STRONG PRESSURE GRADIENT IS
IN PLACE BETWEEN HIGH PRESSURE ACROSS THE SOUTHEAST AND LOW PRESSURE
OVER NORTHWEST ONTARIO AND THE WESTERN GREAT LAKES. THE PRESSURE
GRADIENT IS FORECAST TO REMAIN NEARLY AS STRONG AS IT IS AT PRESENT
OVERNIGHT IF NOT INCREASE A BIT. SHELTERED VALLEY LOCATIONS SHOULD
STILL BE ABLE TO DECOUPLE...BUT MIN T NEAR CROSSOVER TEMPS IN THE MID
TO UPPER 40S OVER THE SOUTHEASTERN COUNTIES ARE LIKELY NOT REACHABLE.
A FEW NORMALLY COLDER LOCATIONS MIGHT DROP TO 48 OR 49...BUT MOST
VALLEYS SHOULD AVERAGE IN THE LOW TO MID 50S. MORE OPEN TERRAIN
LOCATIONS OFT HE FAR WESTERN...NORTHWESTERN AND SOUTHWESTERN CWA
AS WELL AS THE RIDGETOPS SHOULD NOT DROP MUCH BELOW 60S...IF THAT.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 340 PM EDT TUE MAY 14 2013

18Z SFC ANALYSIS SHOWS DEEP LOW PRESSURE MOVING INTO THE UPPER
MIDWEST WITH A FAIRLY TIGHT PRESSURE GRADIENT SPREAD THROUGH
KENTUCKY. THIS IS SUPPORTING BREEZY SOUTH TO SOUTHWEST WINDS THROUGH
THE AREA...HELPING TO BRING IN AN AIR MASS THAT IS WARMER AND
CONTAINS MORE MOISTURE THAN WHAT WE HAD THIS MORNING. THIS IS BORNE
OUT IN THE CURRENT TEMPERATURES AND DEW POINTS ACROSS EAST KENTUCKY.
MID TO UPPER 70S ARE FOUND THROUGH THE CUMBERLAND VALLEY WHILE LOWER
70S ARE REPORTED ELSEWHERE. MEANWHILE...DEW POINTS HAVE CLIMBED INTO
THE LOWER 50S IN THE WESTERN PARTS OF THE AREA TO THE MID 40S IN THE
FAR EAST. FINALLY...SKIES CLEARED EARLY THIS AFTERNOON ALLOWING FOR
PLENTY OF SUNSHINE THAT ALSO SPURRED OUR WARMTH.

THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE FIRST HALF OF THE
SHORT TERM PORTION OF THE FORECAST AND THEN THEY BECOME MORE MUDDLED
WEDNESDAY NIGHT AND THURSDAY. FOR TONIGHT...HEIGHTS WILL BE RISING IN
THE WAKE OF A DEPARTING DEEP TROUGH OFF TO THE EAST. BY MIDDAY
WEDNESDAY...THE RIDGING IN PLACE WILL BE FLATTENING OUT IN RESPONSE
TO A WEAKER SOUTHERN STREAM WAVE INBOUND FROM THE SOUTHERN PLAINS AND
FAST NORTHWEST FLOW PRESSING DOWN FROM THE NORTHERN OHIO VALLEY.
HEADING INTO THURSDAY MORNING...ATTENTION TURNS TO A NEARLY STEADY
STATE WAVE ROLLING EAST INTO THE MID MISSISSIPPI VALLEY. THIS FEATURE
IS STRONGEST IN THE GFS...BUT TIMING IS SIMILAR IN ALL MODELS AND THE
NAM12 NOT FAR OFF FROM CONSENSUS. ACCORDINGLY...USED THE HIGHER
RESOLUTION NAM12 FOR FORECAST DETAILS THROUGH THURSDAY MORNING.

SENSIBLE WEATHER WILL FEATURE A MILDER NIGHT UNDER MOSTLY CLEAR
SKIES...ALONG WITH A DECENT RIDGE TO VALLEY TEMPERATURE SPLIT
TONIGHT. PATCHY FOG WILL BE POSSIBLE TOWARD DAWN...MAINLY NEAR THE
RIVERS AND BODIES OF WATER. WEDNESDAY WILL BE ANOTHER WARM
DAY...THOUGH A FEW MORE CLOUDS CAN BE EXPECTED AND THE WINDS WILL NOT
BE QUITE AS BREEZY...BUT STILL FROM THE SOUTHWEST. WEDNESDAY WILL
CONTINUE AS A MILD TO WARM NIGHT WITH CONVECTION POTENTIALLY PRESSING
DOWN FROM THE NORTH AS A QUASI-STATIONARY BOUNDARY SLIPS SOUTH FROM
THE MIDDLE OF THE OHIO VALLEY TOWARD OUR CWA. HAVE ADDED A SMALL
CHANCE OF SHOWERS AND THUNDERSTORMS FOR THIS OVER OUR NORTHERN
COUNTIES TOWARDS DAWN THURSDAY.

FOR TEMPERATURES...USED PRIMARILY THE CONSSHORT THROUGH MIDDAY
WEDNESDAY AND THEN BLENDED THE CONSALL WITH THE INHERITED GRIDS.
ALSO...MADE SOME SIGNIFICANT CHANGES TO THE LOW TEMPERATURES TONIGHT
BASED ON TERRAIN DIFFERENCES AND ON WEDNESDAY NIGHT...MAINLY JUST IN
THE SOUTH. AS FOR POPS...ENDED UP MOST SIMILAR TO THE MET NUMBERS
THROUGH WEDNESDAY WITH A LEAN TOWARD THE WETTER MAV IN THE NORTH
WEDNESDAY NIGHT.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 359 PM EDT TUE MAY 14 2013

THE MODELS CONTINUE TO AGREE WITH A FLATTER LONG WAVE FLOW PATTERN
FOR THE END OF THE WORK WEEK AND THEN A TRANSITION TO A MORE
AMPLIFIED FLOW THEREAFTER. THE EVOLUTION OF THIS CONTINUES TO BE
HANDLED DIFFERENTLY BETWEEN THE GFS AND ECMWF...SO HAVE MAINTAINED
MUCH OF THE INHERITED POP REGIME WITH SLIGHT MODIFICATIONS BASED ON A
BLEND OF THE LATEST GUIDANCE.

A MORE SUMMER-LIKE PATTERN WILL BE IN PLACE ACROSS EASTERN KENTUCKY
THROUGH EARLY NEXT WEEK...WITH ABOVE NORMAL TEMPERATURES AND MAINLY
DIURNALLY INFLUENCED CONVECTION EACH DAY. THURSDAY WILL FEATURE
BETTER CHANCES OF SHOWERS AND STORMS WITH A NEARLY STATIONARY FRONTAL
BOUNDARY SETTING UP CLOSE TO THE OHIO RIVER.

IN GENERAL...THERE IS A BETTER CONSENSUS OF UPPER LEVEL RIDGING
BUILDING IN THROUGH THE WEEKEND...ALTHOUGH WILL CONTINUE TO MENTION
AT LEAST ISOLATED TO SCATTERED POPS AT TIMES...AS THERE STILL IS
SOME DOUBT IN HOW MUCH CAPPING WILL TAKE PLACE DURING PEAK HEATING.
BY EARLY NEXT WEEK...A DEEPER TROUGH TAKING SHAPE IN THE PLAINS WILL
BEGIN SLIDING EAST. THE TREND HAS BEEN TO SLOW THE EVOLUTION OF THIS
FEATURE DOWN A BIT...KEEPING THE BEST RAIN CHANCES ACROSS CENTRAL
KENTUCKY.

&&

.AVIATION...
-- Changed Discussion --
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 140 AM EDT WED MAY 15 2013

VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. MAIN
FORECAST CONCERN WILL BE LLWS THROUGH THE FIRST 6 TO 8 HOURS OF THE
FORECAST WINDOW. MODEL FORECAST SOUNDINGS INDICATE THIS POTENTIAL.
AND THE KENTUCKY MESONET STATION IN PIKE COUNTY...DORTON AT 2800 FT
ELEVATION IS REPORTING WEST...SOUTHWEST WINDS OF AROUND 20KTS WITH
HIGHER GUSTS TO AROUND 40KTS. WINDS ARE BEING ENHANCED JUST A BIT
DUE TO LAMINAR EFFECTS AT THE TOP OF THE NOCTURNAL INVERSION.
CONSEQUENTLY INCLUDED SOME LLWS AT EACH TAF STATION INTO WEDNESDAY
MORNING. SURFACE WINDS WILL BE RELATIVELY LIGHT...AROUND 4KTS UNTIL
INVERSION BREAKS AND MIXING BEGINS IN ERNST IN THE MORNING. THEN
GRADIENT WINDS WILL INCREASE TO AROUND 10-12KTS WITH HIGHER GUSTS.
-- End Changed Discussion --

&&

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

&&

$$

UPDATE...RAY
SHORT TERM...GREIF
LONG TERM...GEOGERIAN
AVIATION...RAY