Area Forecast Discussion Issued by NWS Jackson, KY
000
FXUS63 KJKL 251425
AFDJKL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1025 AM EDT SAT MAY 25 2013
.UPDATE...
ISSUED AT 1025 AM EDT SAT MAY 25 2013
UPDATED TO REMOVE MORNING FOG AND ALSO BRING IN SOME BETTER CLOUD
COVER THIS AFTERNOON AS THE MID LEVELS MOISTEN UP ALONG THE
DEVELOPING WARM FRONT. OTHERWISE...FEW CHANGES MADE AT THIS TIME.
UPDATE ISSUED AT 800 AM EDT SAT MAY 25 2013
UPDATED TO BETTER DELINEATE FOG IN THE GRIDS THIS MORNING AS IT
DISSIPATES.
UPDATE ISSUED AT 541 AM EDT SAT MAY 25 2013
UPDATED TO INCORPORATE OBSERVED TEMPS INTO TEMP CURVE THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 133 AM EDT SAT MAY 25 2013
A SURFACE RIDGE OF HIGH PRESSURE STRETCHING FROM ONTARIO TO THE
CAROLINAS WILL REMAIN NEARLY STATIONARY DURING THE PERIOD...BRINGING
US A DRY SURFACE AIR MASS. WE WILL HAVE NEARLY NEUTRAL OR SLIGHT
COLD AIR ADVECTION. WITH AN UNUSUALLY COLD AIR MASS INITIALLY IN
PLACE...THE LACK OF SIGNIFICANT COLD AIR ADVECTION WILL ALLOW STRONG
LATE SPRING SUN TO BEGIN TO WARM AND MODIFY THE AIR MASS.
FLOW BETWEEN THE EASTERN CONUS RIDGE AND LOW PRESSURE OVER THE HIGH
PLAINS WILL RESULT IN WARM AIR ADVECTION OVER THE PLAINS AND MIDWEST.
THIS WAS ALREADY CAUSING THUNDERSTORMS OVER IA ON FRIDAY NIGHT.
ADDITIONAL ROUNDS OF CONVECTION ARE EXPECTED OVER THE UPPER MIDWEST
THROUGH SUNDAY. MOISTURE/DEBRIS CLOUDS FROM THAT AREA WILL BE CARRIED
SOUTHEAST BY THE FLOW ALOFT. THIS WILL BRING AN INCREASE IN CLOUDS
LOCALLY. CAN NOT RULE OUT PRECIP LATE TONIGHT OR SUNDAY...BUT VIRGA
IS THE MORE LIKELY SCENARIO WITH OUR DRY SURFACE AIR MASS IN PLACE.
WILL CARRY JUST A CHANCE OF SPRINKLES TONIGHT AND SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 AM EDT SAT MAY 25 2013
THE MODELS WERE IN BETTER AGREEMENT THIS GO ROUND. OVERALL THE
WEATHER IN THE EXTENDED WILL BE DOMINATED BY A LARGE RIDGE OF HIGH
PRESSURE. THIS WEATHER SYSTEM WILL BRING WARM AND DRY WEATHER TO
EASTERN KENTUCKY FOR MOST OF THE WEEK. THE EXCEPTION COULD BE THE
SUNDAY NIGHT THROUGH MONDAY NIGHT TIME FRAME. THE GFS...ECMWF...AND
SREF MODELS ALL HAVE ISOLATED SHOWERS AND STORMS FORMING OVER THE
NORTHERN HALF OF EASTERN KENTUCKY SUNDAY NIGHT INTO MONDAY NIGHT...AS A
WEAK AND ILL DEFINED FRONTAL BOUNDARY DRIFTS SLOWLY NORTHWARD ACROSS
THE AREA AND INTO THE OHIO VALLEY. THAT HAS BEEN THE CASE FOR SEVERAL
MODEL RUNS NOW...SO DECIDED TO LEAVE IN A SLIGHT CHANCE OF RAIN FOR
THE FIRST FEW PERIODS OF THE EXTENDED. THE MODEL SOUNDINGS DID INDICATE
THAT ENOUGH INSTABILITY WOULD BE PRESENT FOR A STORM OR TWO TO
FORM...PARTICULARLY DURING THE AFTERNOON AND EVENING HOURS ON MONDAY.
AFTER MONDAY NIGHT...A VERY LARGE AND STRONG RIDGE OF HIGH PRESSURE
IS PROGGED TO SETTLE OVER THE AREA. THE SINKING AIR...AND SUBSEQUENT
DRYING IN LOW AND MIDDLE LEVELS...WILL LEAD TO STRENGTHENING HIGH
PRESSURE AT THE SURFACE AND ALOFT AND STEADY WARMING FROM TUESDAY
ONWARD. TEMPERATURES FROM TUESDAY THROUGH THE END OF THE WEEK WILL
LIKELY WARM TO ABOVE THE MEXMOS GUIDANCE VALUES...AS HIGH PRESSURE
STRENGTHENS AND CLOUD COVER IS AT A MINIMUM AND SOUTHERLY WINDS
BECOME ESTABLISHED. ADJUSTMENTS WERE MADE TO THE TEMPERATURE FORECAST
BASED ON THE AFOREMENTIONED REASONING. THE WARMEST DAYS OF THE WEEK
WILL BE WEDNESDAY THROUGH FRIDAY...AS HIGH PRESSURE WILL BE AT ITS
PEAK INTENSITY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 626 AM EDT SAT MAY 25 2013
LOCALLY DENSE VALLEY FOG WILL AFFECT SOME LOCATIONS EARLY THIS
MORNING...INCLUDING KSME. IT WILL QUICKLY DISSIPATE IN MOST PLACES BY
AROUND 13Z. OTHERWISE...VFR AND LIGHT WINDS ARE EXPECTED THROUGH
THE PERIOD. SOME LIGHT RAIN CAN NOT BE RULED OUT LATE TONIGHT...BUT
IF IT OCCURS IT WOULD PROBABLY NOT AMOUNT TO MUCH MORE THAN
SPRINKLES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...HAL
LONG TERM...AR
AVIATION...HAL