Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 250608 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
208 AM EDT WED MAR 25 2015

.UPDATE...
ISSUED AT 208 AM EDT WED MAR 25 2015

CLOUDS HAVE THINNED ENOUGH SOUTH OF I-64 TO ALLOW FOR SOME VALLEY
DECOUPLING...AS TEMPERATURES HAVE DROPPED INTO THE LOWER 40S IN
PLACES. SHOWERS HAVE LIFTED NORTH OF THE AREA AS SCHEDULED...WITH
MORE SCATTERED ACTIVITY LIKELY ENTERING FROM THE WEST CLOSER
TOWARDS DAWN. HAVE FRESHENED UP THE GRIDS ACCORDING TO THE LATEST
RADAR TRENDS AS WELL AS UPDATED THE HOURLY TEMPERATURES AND DEW
POINTS TO ACCOUNT FOR THE COOLER DROP OFF FOR THE NEXT FEW
HOURS...BEFORE LEVELING OFF CLOSER TO DAWN...AS CLOUDS INCREASE
ONCE AGAIN. UPDATES HAVE BEEN SENT.

UPDATE ISSUED AT 937 PM EDT TUE MAR 24
2015

AN AREA OF SHOWERS EXTENDED FROM LESLIE COUNTY NW INTO SOUTHERN
INDIANA AT MID EVENING AND WAS MOVING EAST. THE SHOWERS WERE
HEAVIEST AND MOST EXTENSIVE IN THE NW PART OF THE PRECIP
AREA...AND LIGHTEST AND SPOTTIEST IN THE SOUTHEAST IN THE JKL
FORECAST AREA. HAVE MODIFIED THE FORECAST TO ACCOUNT FOR THE
TRENDS OF THIS AREA OF SHOWERS. ASIDE FROM THIS...LITTLE OR NO
PRECIP IS EXPECTED UNTIL THE REMNANTS OF THE SHOWERS/THUNDERSTORMS
OVER SOUTHERN ILLINOIS AND SOUTHEAST MISSOURI POTENTIALLY REACH
OUR NW COUNTIES TOWARD DAWN.

UPDATE ISSUED AT 652 PM EDT TUE MAR 24 2015

SKIES WERE CLOUDY OVER MUCH OF THE AREA EARLY THIS EVENING...AND
HAVE UPDATED THE FORECAST TO ACCOUNT FOR THE GREATER AMOUNT OF SKY
COVER. WILL STILL LOOK FOR SOME BREAKS IN THE CLOUDS DURING THE
NIGHT...BUT SKIES SHOULD REMAIN PARTLY TO MOSTLY CLOUDY AS A
WHOLE OVERNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 400 PM EDT TUE MAR 24 2015

19Z SFC ANALYSIS SHOWS A WELL DEFINED AREA OF LOW PRESSURE LIFTING
NORTHEAST INTO THE MIDWEST WHILE A DEVELOPING WARM FRONT STRETCHES
EAST FROM ITS CORE THROUGH CENTRAL KENTUCKY. THIS BOUNDARY HAS
BEEN RESPONSIBLE FOR A DICHOTOMY OF CONDITIONS ACROSS EAST
KENTUCKY THIS AFTERNOON. READINGS AT 3 PM RANGED FROM THE UPPER
40S NORTH OF IT...WHERE IT HAS RAINED AND BEEN MOST CLOUDY...TO
THE LOWER 70S IN THE SOUTH...DESPITE INCREASING CLOUDS. DEW POINTS
WERE STARTING TO MOISTEN THROUGH NORTHERN PARTS OF THE CWA AS
SHOWERS AND SPRINKLES ARE STARTING TO BUILD ALONG THE BOUNDARY...
BUT STILL ARE 10 TO 15 DEGREES LOWER THAN THE VALUES IN THE FAR
SOUTH. WINDS REMAIN LIGHT AND VARIABLE.

THE MODELS ARE IN GOOD AGREEMENT ALOFT AS ONE WAVE MOVES OFF TO
THE NORTHEAST OF KENTUCKY AND ANOTHER STRONGER ONE APPROACHES FROM
THE MID MISSISSIPPI VALLEY TONIGHT. THIS WESTERN WAVE MOVES INTO
THE OHIO VALLEY BY WEDNESDAY MORNING AS THE TROUGH IT ACCOMPANIES
PIVOTS INTO THE GREAT LAKES. MORE ENERGY WILL THEN POUR INTO THE
CENTRAL PLAINS DURING THE DAY WEDNESDAY AS A FULL LATITUDE TROUGH
BEGINS TO TAKE SHAPE TO OUR WEST AND STARTS TO MOVE THIS WAY BY
THURSDAY MORNING. THE MODEL SIMILARITIES WARRANT A GENERAL BLEND
ALONG WITH A LEAN TOWARD THE HIGHER RESOLUTION NAM12 AND HRRR...AT
LEAST INITIALLY.

SENSIBLE WEATHER WILL FEATURE A DECENT CHANCE OF RAIN OVER THE
NORTHERN HALF OF THE CWA THIS EVENING AS THE WARM FRONT MOVES
NORTHEAST WHILE BECOMING MORE ACTIVE IN RESPONSE TO THE PARENT
SFC LOW RACING INTO THE GREAT LAKES. THIS WILL PLACE EASTERN
KENTUCKY IN THIS DYNAMIC SYSTEM/S WARM SECTOR WITH ITS COLD FRONT
APPROACHING BY MORNING. WHILE THE BEST ENERGY WILL PASS JUST
NORTHWEST OF THE AREA...AN ACTIVE COLD FRONT AND BETTER INFLOW OF
HIGHER DEW POINT AIR TO THE SOUTH WILL MEAN A POTENTIAL FOR
THUNDERSTORMS AS THE FRONT MOVES INTO THE CWA ON WEDNESDAY. CAPES
CLIMB UP TOWARD 1000 J/KG AND LIS FALL INTO THE LOW SINGLE DIGITS
BELOW ZERO FROM MIDDAY WEDNESDAY AND INTO THE EVENING. THE FRONT
WILL THEN STALL OUT IN THE AREA AS ANOTHER WAVE DEVELOPS ALONG IT
AND STARTS TO HEAD THIS WAY FROM THE SOUTHERN PLAINS WEDNESDAY
NIGHT. WILL CONTINUE THE RISK OF ISOLATED THUNDERSTORMS THROUGH
WEDNESDAY NIGHT...CONCENTRATED OVER OUR NORTHERN COUNTIES AT
DAYBREAK.

AGAIN STARTED WITH THE SHORTBLEND FOR THE T/TD/WIND GRIDS INTO
WEDNESDAY MORNING AND THE SUPERBLEND FOR THE REST OF THE SHORT
TERM. DID MAKE MINOR POINT AND TERRAIN BASED ADJUSTMENTS TO TEMPS
TONIGHT. AS FOR POPS...ENDED UP CLOSEST TO THE MET GUIDANCE...
OVERALL...BUT ALSO SIMILAR TO THE MAV FOR THE SOUTHERN PARTS OF
THE CWA THROUGH THURSDAY MORNING.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 330 PM EDT TUE MAR 24 2015

PATTERN APPEARS QUITE ACTIVE FOR THE EXTENDED PORTION OF THE
FORECAST. OVERALL....UPPER LEVEL FLOW IS PROGRESSIVE...TYPICAL FOR
SPRING AND UNTIL THE LAST 24-36 HOURS OF THE PERIOD MODEL SOLUTIONS
ARE IN BETTER AGREEMENT THAN NORMAL...INCREASING CONFIDENCE IN THE
FORECAST.

ENERGY DROPPING OUT OF CANADA WILL CARVE OUT A DEEP TOUGH ACROSS THE
ENTIRE EASTERN CONUS. ADDITIONAL WAVES OF ENERGY WILL FOLLOW TENDING
TO KEEP A MEAN TROUGH OVER OUR REGION. THE MAIN OR MOST SIGNIFICANT
TROUGH TO INFLUENCE OUR WEATHER LATE IN THE WEEK WILL INTRODUCE
CONSIDERABLY COLDER AIR ACROSS THE EASTERN HALF OF THE NATION...WITH
SUB ZERO H850 TEMPERATURES REACHING THE AS FAR SOUTH AS THE GULF OF
MEXICO.

A WEAK FRONTAL BOUNDARY WILL DROP INTO THE AREA WEDNESDAY BUT WILL
WASH OUT AS ITS UPPER LEVEL SUPPORT ALOFT OUT RUNS THE SFC BOUNDARY.
BY THEN THE MORE SUBSTANTIAL...DEEPER TROUGH DIGGING SOUTHWARD OUT
OF CANADA WILL INDUCE A SFC LOW THAT WILL MOVE THROUGH THE MID
MISSISSIPPI AND LOWER OHIO VALLEY. THIS FEATURE WILL PROVIDE OUR
BEST CHANCE OF PRECIPITATION THROUGH THE WEEK...LATE WEDNESDAY NIGHT
INTO THURSDAY AS IT DRAGS ANOTHER FRONTAL BOUNDARY THROUGH THE
COMMONWEALTH. IN GENERAL MODELS HAVE BEEN TRENDING A BIT SLOWER WITH
THE PASSAGE OF THIS MAIN COLD FRONTAL SYSTEM. CONSEQUENTLY...
EXPECTATION ARE THAT THE THREAT OF THUNDERSTORMS WILL LINGER INTO
THURSDAY...ALONG AND AHEAD OF THE SECOND FRONTAL BOUNDARY THAT IS
EXPECTED TO HAVE MADE THE CIRCUIT THROUGH EASTERN KENTUCKY NO LATER
THAN SOMETIME THURSDAY AFTERNOON. THE 12Z GFS IS SLIGHTLY FASTER
WITH THE TIMING OF THIS SECOND FRONTAL BOUNDARY THAN THE 0Z ECMWF. A
THIRD FRONTAL BOUNDARY...MORE ARCTIC IN NATURE...WILL FOLLOW ON THE
HEELS OF THE SECOND...PASSING THROUGH OUR AREA ON FRIDAY AND
FUNCTIONING AS THE TRUE OPERATIVE FOR BRINING IN THE UPCOMING SHOT
OF COLD AIR THAT WILL INVADE THE COAL FIELDS FOR THE FIRST HALF OF
THE WEEKEND. AT PRESENT THERE DOES APPEAR TO BE SOME SCT SHOWER
ACTIVITY ASSOCIATED WITH THE FRONT ON FRIDAY. TEMPERATURE PROFILES
WILL BECOME COLD ENOUGH THAT WE SHOULD SEE A CHANGE OVER TO SNOW
THROUGH THE DAY FRIDAY INTO FRIDAY EVENING. A WIDESPREAD FREEZE
APPEARS INCREASINGLY LIKELY FOR SATURDAY MORNING. FROST AND OR A
FREEZE WILL BE POSSIBLE AGAIN SUNDAY MORNING WE WELL...ESPECIALLY IN
OUR COLDER EASTERN VALLEY LOCATIONS SUNDAY. HOWEVER...THE EXTENT OF
THE COLD TEMPERATURES WILL DEPEND GREATLY ON RESIDUAL CLOUD COVER
AND THE ALIGNMENT OF THE SFC HIGH PRESSURE SYSTEM OVER OUR AREA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 208 AM EDT WED MAR 25 2015

VFR CONDITIONS ARE EXPECTED TO CONTINUE TO HOLD ON ACROSS THE AREA
THROUGH THE PERIOD. A STRENGTHENING LOW LEVEL JET WILL ALLOW FOR
SOME LOW LEVEL WIND SHEAR OVERNIGHT AND INTO THE MID-MORNING
HOURS. SOME SHOWERS WILL THREATEN MAINLY THE I-64 CORRIDOR TOWARDS
DAWN...BEFORE DRYING UP AFTER 15Z OR SO. ONCE THE INVERSION MIXES
OUT BY THE MID-MORNING...SSW WINDS OF 5 TO 10 KTS...WITH SOME
GUSTS OF AROUND 15 KTS WILL ENGAGE...BEFORE DIMINISHING CLOSER TO
00Z. EXPECT OCCASIONAL CEILINGS AT 5K FEET AGL FROM EARLY THIS
MORNING THROUGH THE EVENING.

&&

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

$$

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



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