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000
FXUS63 KJKL 151045
AFDJKL

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

.UPDATE...
ISSUED AT 645 AM EDT WED MAY 15 2013

FORECAST IS GENERALLY ON TRACK THIS MORNING. A LIGHT SOUTHWEST
GRADIENT SURFACE WIND HAS KEPT TEMPS UP IN MOST AREAS OVERNIGHT...
WITH THE EXCEPTION BEING OUR EASTERN VALLEY LOCATIONS WHICH HAVE
MANAGED TO DECOUPLE. ADJUSTED TEMPS TO REFLECT THIS. IN ADDITION
THERE IS SOME BACK BUILDING OF CLOUDS TO THE SOUTHWEST INTO OUR AREA
ASSOCIATED WITH THE WARM FRONTAL SYSTEM THAT CONTINUES TO PUSH OFF
TO OUR EAST...NORTHEAST. BUT DO NOT EXPECT THESE CLOUDS TO LINGER IN
OUR AREA MUCH LONGER. ADJUSTED THE GRIDS TO INCLUDE SOME ADDITIONAL
BUT TEMPORARY CLOUD COVER IN OUR FAR EAST. THIS DOES NOT AFFECT THE
ZONES HOWEVER. ADDITIONAL OTHER CHANGES TO THE FORECAST PACKAGE ATTM.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 440 AM EDT WED MAY 15 2013

08Z SFC ANALYSIS SHOWS DEEP LOW PRESSURE MOVING INTO THE GREAT LAKES
REGION A FAIRLY TIGHT PRESSURE GRADIENT SPREAD THROUGH KENTUCKY.
THIS IS SUPPORTING AT LEAST A LIGHT SOUTHWEST GRADIENT SURFACE WIND
AND IS KEEPING TEMPS UP IN MOST AREAS...EXCEPTION BEING OUR EASTERN
VALLEY LOCATIONS WHICH HAVE MANAGED TO DECOUPLE.

THE MODELS ARE IN VERY GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. FOR TODAY...SHORT WAVE RIDGE WILL BE
FLATTENING OUT IN RESPONSE TO A WEAKER SOUTHERN STREAM WAVE INBOUND
FROM THE SOUTHERN PLAINS. HEADING INTO THURSDAY MORNING...ATTENTION
TURNS TO A CLOSED LOW THAT QUICKLY OPENS UP INTO A WAVE ROLLING EAST
INTO THE MID MISSISSIPPI VALLEY. HOWEVER...THIS FEATURE QUICKLY
BECOMES LESS ORGANIZED AND MUDDLED. BUT TIMING IS SIMILAR IN ALL
MODELS AND THE NAM12 NOT FAR OFF FROM CONSENSUS. ACCORDINGLY...
LEANED STRONGLY TOWARDS THE HIGHER RESOLUTION NAM12 FOR FORECAST
DETAILS INTO THURSDAY.

SENSIBLE WEATHER WILL FEATURE ANOTHER WARM DAY...THOUGH SEVERAL
DEGREES WARMER THAN TUESDAY AS AFTERNOON TEMPERATURES CLIMB WELL INTO
THE 80S. FOR MOST...BEING ACCUSTOMED TO THE COOL SPRING THUS FAR IT
MAY ACTUALLY FEEL ON THE VERGE OF BEING UNCOMFORTABLY HOT. TONIGHT
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 CARRIED
OVER A CHANCE OF SHOWERS AND THUNDERSTORMS FOR THIS POTENTIAL OVER
OUR NORTHERN MOST COUNTIES TOWARDS DAWN THURSDAY...GENERALLY NORTH OF
THE I64 CORRIDOR. NAM12 WITH SUPPORT FROM THE SHREF HINTS AT SOME
MORE ORGANIZED CONVECTION DROPPING SOUTHEAST INTO OUR AREA DURING THE
DAY THURSDAY...BUT NEVER QUITE MAKING IT AS FAR SOUTH AS THE HAL
ROGERS PARKWAY. THIS EFFECTIVELY PUTS A FAIRLY TIGHT GRADIENT OF POPS
ACROSS OUR AREA THURSDAY...LIKELY IN THE NORTH...NORTHEAST TO ONLY
CHANCE IN OUR SOUTHERNMOST COUNTIES ALONG THE TN/KY STATE LINE. FOR
TEMPERATURES... JUST TWEAKED INHERITED TEMPS WHICH LOOK QUITE GOOD
TOWARDS A CONSENSUS BLEND OF MODEL GUIDANCE.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 440 AM EDT WED MAY 15 2013

THE MODELS START OUT IN EXCELLENT AGREEMENT. THE PATTERN IS TRYING
TO UNDERGO A TRANSITION. BY THURSDAY NIGHT AN UPPER TROUGH WILL DROP
IN ALONG THE WEST COAST WITH SOME WEAK RIDGING OVER THE NORTH
CENTRAL US INTO CANADA AND THE ANOTHER UPPER TROUGH OFF OF THE EAST
COAST. THERE IS ALSO A WEAK WEAK UPPER LOW OVER SOUTHERN MISSOURI
WHICH WILL BE DRIFTING TO THE EAST SOUTHEAST. AT THE SURFACE A WARM
FRONT WILL EXTEND FROM A LOW NEAR THE DAKOTAS BORDER AND THEN CURVE
ACROSS SOUTHERN OHIO. THE MODEL CONSENSUS HAS THE PRECIPITATION
MOVING TO THE NORTH FROM EARLIER IN THE DAY WITH JUST SOME RESIDUAL
ISOLATED SHOWERS LEFT OVER EASTERN KENTUCKY. BY SATURDAY MORNING THE
WARM FRONT IS FORECAST TO MOVE TO THE SOUTH AND IS EXPECTED TO BE
BISECTING EASTERN KENTUCKY. THE FRONT IS EXPECTED TO STAY INTO THE
AREA THROUGH SUNDAY AND THEN MOVE BACK TO THE NORTH AS THE LOW LEVEL
JET OUT AHEAD OF THE APPROACHING COLD FRONT SURGES THE FRONT TO THE
NORTH. THE COLD FRONT IS EXPECTED TO MOVE ACROSS THE AREA ON
TUESDAY. THIS SHOULD BE A STRONG FRONT WITH SOME PRETTY GOOD COLD
AIR ADVECTION BEHIND IT. THIS WILL BRING THE TEMPERATURES BACK DOWN
BELOW AVERAGE ON WEDNESDAY. WITH A WEAK WARM FRONTAL BOUNDARY BEING
THE MAIN WEATHER MAKER...CONFIDENCE IS PRETTY LOW AFTER SATURDAY DUE
TO THE FACT THAT THE MODELS REALLY DO NOT HANDLE WARM FRONTAL
BOUNDARIES VERY WELL. THE WEATHER PATTER IS WARM AND UNSETTLE...THE
ONLY QUESTION IS HOW UNSETTLED WILL IT BE. FOR TEMPERATURES NUDGED
THE MODEL CONSENSUS BLEND TOWARD THE NEW ECMWF. FOR TIMING...ALSO
WENT MORE WITH THE ECMWF TIMING.

OKLAHOMA WHICH WILL BE DRIFTING TO THE EAST IN A RATHER WEAK
SOUTHERN STREAM. BY FRIDAY MORNING THE UPPER LOW IS FORECAST TO BE
OVER NORTHERN GEORGIA AND AN UPPER TROUGH STARTS DIGGING IN ALONG
THE WEST COAST. THE TRICKY PART OF THE FORECAST IS THE POSITION OF A
WEAK WARM FRONT FROM THURSDAY THROUGH SATURDAY TIME PERIOD AND THE
POSITING OF THE SURFACE RIDGE AXIS. THE AREA WILL BE IN THE WARM
SECTOR WITH WARM AND FAIRLY MOIST AIR ACROSS THE AREA. DEPENDING OF
THE FRONT AND THE HIGH...THERE COULD BE ISOLATED AFTERNOON SHOWERS
OR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. TENDED TO GO
WITH THE DRIER ECMWF SOLUTION AND PUT IN AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS. THE NEXT GOOD COLD FRONT WILL NOT MOVE
THROUGH THE AREA UNTIL NEXT WEDNESDAY. WITH THE HEAT AND
SHOWERS...IT SHOULD BE A MAJOR TASK TO KEEP THE GRASS MOWED THIS
NEXT WEEK. TEMPS WILL REMAIN ABOVE NORMAL THROUGH THE PERIOD.
CONFIDENCE IN THE GENERAL WARM MOIST PATTERN IS HIGH...THE
CONFIDENCE IN THE TIMING AND EXTENT OF PRECIPITATION IS LOWER THAN
AVERAGE.

&&

.AVIATION...(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.


&&

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

&&

$$

UPDATE...RAY
SHORT TERM...GREIF/RAY
LONG TERM...JJ
AVIATION...RAY