Flash Flooding and Flooding in Kentucky, April 14 to 16, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
936 PM EDT FRI APR 13 2007

.SHORT TERM.../THE REST OF TODAY/...UPDATED
SOME LIGHT RAIN HAS DEVELOPED OVER EASTERN KENTUCKY IN AN AREA OF
ISENTROPIC LIFT THAT IS OUT AHEAD OF THE WARM FRONT. THE WARM FRONT WILL
BE MOVING INTO THE AREA AFTER MIDNIGHT. THIS ISENTROPIC LIFT WILL BE
CAUSING SOME INTERMITTENT LIGHT RAIN AS IT MOVES ACROSS THE AREA THIS EVENING.
AS THE WARM FRONT GETS NEARER...THE RAIN WILL BECOME MORE WIDESPREAD
AND INTENSE. AN AREA OF THUNDERSTORMS WHICH IS CURRENTLY OVER
NORTHERN ALABAMA AND CENTRAL TENNESSEE WILL BE MOVING TOWARD THE
AREA. DID NOT FORECAST ANY THUNDERSTORMS IN THE OVERNIGHT
PERIOD...HOWEVER SOME MAY SNEAK INTO THE I 75 CORRIDOR BY THE WEE HOURS
OF THE MORNING. THE REST OF THE FORECAST IS ON TRACK AND NO FURTHER
UPDATES ARE EXPECTED.

THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...

/TONIGHT THROUGH SUNDAY NIGHT/

MAJOR STORM SYSTEM TO AFFECT EASTERN KENTUCKY DURING THE
PERIOD...ALONG WITH ABOUT HALF OF THE CONUS. THE MOST SIGNIFICANT
DIFFERENCES IN THE MODELS INVOLVE HOW MUCH COLD AIR MAKES IT IN HOW
QUICKLY BEHIND THE DEPARTING LOW. THERE ARE ALSO SOME DIFFERENCES IN
TIMING OF THE MOST DEFINITE TIMES FOR RAIN...BUT IN TERMS OF 12 HOUR
POPS...IT MAKES LITTLE DIFFERENCE IN THE OUTCOME. HAVE GENERALLY
SIDED WITH THE WRF FOR THE FIRST COUPLE OF PERIODS...FAVORING ITS
DETAIL. TRANSITIONED TO A FAVOR FOR THE GFS IN THE LAST COUPLE OF
PERIODS...FAVORING ITS HANDLING OF THE SYNOPTIC SCALE AT LONGER
FORECAST TIMES.

IN TERMS OF WEATHER...RAIN IS EXPECTED TO DEVELOP OVER THE AREA
TONIGHT DUE TO ISENTROPIC LIFT AND AID FROM RIGHT SIDE OF
ANTICYCLONIC UPPER JET...WITH MORE RAIN ON SATURDAY AND SATURDAY
NIGHT. ELEVATED INSTABILITY COULD ALSO PRODUCE A FEW RUMBLES OF
THUNDER ON SATURDAY. MODELS SUGGEST HEAVIEST RAINFALL WILL BE
SATURDAY INTO SATURDAY NIGHT IN OUR SOUTHEAST COUNTIES...WITH
POTENTIAL FOR TOTALS AROUND 2 INCHES ON AVERAGE. WITH RECENT LACK OF
SIGNIFICANT RAIN...FLOOD GUIDANCE IS RUNNING FAIRLY HIGH. RAINFALL IN
THE EVENT IS MOST LIKELY TO COME OVER A PROLONGED PERIOD...WHICH
WOULD LIMIT FLOOD THREAT. HOWEVER...SITUATION WILL NEED TO CONTINUE
TO BE MONITORED...TO SEE IF LOCALIZED EXCESSIVE RAINFALL DEVELOPS.

AS THE INTENSE AND STILL DEEPENING LOW PRESSURE CENTER MOVES BY TO
OUR SE SATURDAY NIGHT AND SUNDAY...COLD AIR WILL OVERSPREAD THE
REGION ON THE BACK SIDE OF THE STORM. SOUNDINGS INDICATE A POTENTIAL
FOR A CHANGE TO SNOW ON SUNDAY AND SUNDAY NIGHT...ESPECIALLY AT
ELEVATIONS ABOVE ABOUT 2500-3000 FEET. HAVE MENTIONED SOME LIGHT
ACCUMULATIONS POSSIBLE IN THOSE AREAS.

IN TERMS OF TEMPERATURES...HAVE STRAYED A BIT FROM MOS FOR HIGHS ON
SATURDAY IN OUR NORTHERN COUNTIES. MODEL DATA SUGGESTS THERE WILL BE
A TIGHT TEMPERATURE GRADIENT ACROSS THE AREA...WITH A POTENTIAL FOR
READINGS BELOW MOS IN THE NORTH. THE TEMP FORECAST IN THE SOUTHEAST
ON SATURDAY HAS A BIT MORE CONFIDENCE...WITH READINGS EXPECTED IN THE
NEIGHBORHOOD OF MOS GUIDANCE.

.LONG TERM.../MONDAY THROUGH FRIDAY/

MODELS CONTINUE TO BE IN DECENT AGREEMENT THROUGH THE PERIOD AND THE
GFS HAS HAD GOOD RUN TO RUN CONTINUITY...AT LEAST THROUGH DAY 5.
MOST SIGNIFICANT DIFFERENCES CONTINUE TO SHOW UP TOWARDS THE END OF
THE PERIOD AND CENTERS AROUND HOW MODELS HANDLE SHORT WAVE ENERGY
DROPPING DOWN THROUGH THE GREAT LAKES REGION ON THURSDAY.

EXITING WEEKEND STORM SYSTEM WILL KEEP THE THREAT OF PRECIPITATION
IN THE FORECAST EARLY IN THE PERIOD...MAINLY DUE TO UPSLOPE FLOW.
PRECIPITATION MAY MIX WITH SOME SNOW EARLY MONDAY MORNING...
ESPECIALLY IN THE HIGHER ELEVATIONS. THEREAFTER...SHORT WAVE RIDGING
WILL ALLOW FOR A BRIEF WARM UP INTO THE MID WEEK TIME FRAME. A WEAK
STORM SYSTEM WILL TAKE SHAPE OVER THE PLAINS AND MOVE INTO THE TN
VALLEY ON WEDNESDAY. THIS SYSTEM LOOKS SOMEWHAT DISORGANIZED AND
STRUGGLES TO GENERATE MUCH MORE THAN CLOUDS. MODELS HAVE TRENDED
FURTHER SOUTH WITH THIS SYSTEM AS WELL. THEREFORE...CONTINUED TO ONLY
CARRY A SLIGHT POP WEDNESDAY. EXTENDED THE SLIGHT POP OUT INTO
THURSDAY WITH QUESTIONABLE TIMING OF SHORT WAVE ENERGY WHICH BRUSHES
BY JUST TO OUR NORTHEAST LATE WEDNESDAY INTO THURSDAY MORNING. GFS
CONTINUES TO FLIP FLOP WITH MOVEMENT OF THIS DISTURBANCE...SO
CONFIDENCE IS LOW. WILL WAIT AND SEE HOW CONSISTENT THE GFS BECOMES
WITH LATEST 12Z GFS RUN WHICH SWINGS THIS DISTURBANCE OVER EASTERN
KENTUCKY LATE WED NIGHT.

TEMPERATURES THROUGH THE PERIOD HAVE TRENDED A BIT WARMER...MAINLY
DUE TO LESS CLOUD COVER AND MORE SUN WITH THE MORE SOUTHERLY TRACK
OF MID WEEK SYSTEM.
&&

.AVIATION.../00Z TO 24Z/
DECK OF MIDDLE CLOUDS WITH VFR CEILINGS OF 5-8K HAVE BEGUN STREAMING
INTO THE FORECAST AREA AT BOTH SME AND LOZ. BROKEN 10K CLOUD DECK
IN PLACE AT JKL. SOME DRIZZLE AND LIGHT RAIN ALSO FALLING AT SME AT THIS
TIME. EXPECT THIS TREND TO CONTINUE THROUGH 5 OR 6Z...WHEN RAINFALL
SHOULD OVERSPREAD ALL THREE TAF SITES. CEILINGS SHOULD FIRST FALL
INTO MVFR CATEGORY AT JKL AT AROUND 12Z AS WARM FRONT MOVES NORTH
ACROSS THE FORECAST AREA. LOZ AND SME SHOULD REMAIN IN VFR
CONDITIONS IN WARM SECTOR AS A WARM FRONT APPROACHES FROM THE WEST.
ANTICIPATE DROP IN CEILINGS TO THE LOWER END OF THE IFR CATEGORY AT
JKL AFTER 14Z...AFTER 15Z AT SME...AND AFTER 17Z AT LOZ. AN ISOLATED
THUNDERSTORM CAN NOT BE RULED OUT THIS TIME AT ALL TAF SITES...ESPECIALLY
AFTER 18Z.

&&

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

&&

SHORT TERM...HAL/JJ
LONG TERM....RAY
AVIATION...AR

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON KY
534 PM EDT FRI APR 13 2007

KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120-150045-
FLEMING-MONTGOMERY-BATH-ROWAN-ESTILL-POWELL-MENIFEE-ROCKCASTLE-
JACKSON-PULASKI-LAUREL-WAYNE-MCCREARY-WHITLEY-KNOX-BELL-HARLAN-
ELLIOTT-MORGAN-JOHNSON-WOLFE-MAGOFFIN-FLOYD-LEE-BREATHITT-KNOTT-
OWSLEY-PERRY-CLAY-LESLIE-LETCHER-MARTIN-PIKE-
534 PM EDT FRI APR 13 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN KENTUCKY.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.
THUNDERSTORMS ARE POSSIBLE ON SATURDAY. PERIODS OF HEAVY RAIN ARE
POSSIBLE ON SATURDAY THROUGH SATURDAY NIGHT. ACCUMULATIONS OF 1 TO 2
INCHES IS EXPECTED THOROUGH SATURDAY NIGHT. THE HEAVIEST RAINFALL
AMOUNTS SHOULD BE SOUTH OF THE HAL ROGERS PARKWAY AND ALONG VIRGINIA
BORDER. FOR ELEVATIONS BELOW 2500 FEET...A MIX OF RAIN AND SNOW
SHOWERS ARE EXPECTED ON SUNDAY NIGHT. FOR ELEVATIONS ABOVE 2500
FEET...SNOW IS LIKELY ON SUNDAY AND SUNDAY NIGHT. THE BEST CHANCE
FOR SOME LIGHT ACCUMULATIONS IS FOR ELEVATIONS ABOVE 2500 FEET.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

JJ