Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 280353
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1053 PM EST THU NOV 27 2014

.UPDATE...
ISSUED AT 1041 PM EST THU NOV 27 2014

CLOUD COVER CONTINUES TO PLAGUE EASTERN KY AND POINTS TO OUR N AND E.
LATEST SATELLITE IMAGERY IS STARTING TO SHOW SIGNS OF EROSION ALONG
THE WESTERN EDGE OF THESE CLOUDS...CURRENTLY COVER WEST CENTRAL KY.
HOWEVER...IT WILL STILL TAKE SEVERAL HOURS BEFORE OUR CWA BEGINS
CLEARING OUT...IN WHICH CASE CONTINUING THE CLOUD COVER SEVERAL HOURS
LONGER IN THE GRIDS WAS WARRANTED. GIVEN THE NW WINDS...FALLING TEMPS
30 AND BELOW...AND ABUNDANT CLOUD COVER...FLURRIES AND A FEW LIGHT
SNOW SHOWERS ARE CONTINUING TO SHOW UP ACROSS EASTERN KY AND IN
NEIGHBORING CWAS AS WELL. THE UPDATE MADE EARLIER THIS EVENING
INTRODUCED ISOLATED FLURRIES ACROSS MUCH OF THE CWA INTO THE
OVERNIGHT. HOWEVER...LOOKING BACK...THESE FLURRIES WOULD PROBABLY
HAVE WARRANTED EITHER A SCATTERED OR WIDESPREAD WORDING. WITH THIS
UPDATE...WENT AHEAD AND INCREASED COVERAGE TO SCATTERED...SINCE IT IS
LIKELY THAT MANY LOCATIONS ARE SEEING SOME STOPPING AND ENDING TO THE
FLURRIES...INSTEAD OF CONTINUOUS WIDESPREAD COVERAGE. EXPECT THESE
FLURRIES TO CONTINUE UNTIL LATE TONIGHT...WHEN DRIER AIR FINALLY
MOVES ACROSS EASTERN KY AND CLOUDS BEGIN TO CLEAR OUT. IN ADDITION TO
THESE CHANGES...ALSO LOADED IN THE LATEST OBSERVATIONAL GUIDANCE FOR
TEMPS...DEW POINTS...AND WINDS...TO MAKE SURE THESE NEAR TERM GRIDS
WERE ON TRACK WITH THE CURRENT CONDITIONS.

UPDATE ISSUED AT 708 PM EST THU NOV 27 2014

LATE THIS AFTERNOON...RADAR AND OBS CONTINUED TO SHOW REPORTS OF ISL
TO SCT FLURRIES ACROSS MUCH OF EASTERN KY. AS SUCH...WENT AHEAD AND
INCREASED THE COVERAGE OF FLURRIES FOR MUCH OF EASTERN KY THROUGH THE
REMAINDER OF THE EVENING...TAPERING OFF AS CLOUDS ARE EXPECTED TO
CLEAR AFTER MIDNIGHT. UNFORTUNATELY...BOTH THE LATEST FORECAST
SOUNDINGS...AND THE CURRENT SATELLITE TRENDS...SUPPORT CLOUDS
POSSIBLY STICKING AROUND LONGER THAN WAS ORIGINALLY PREDICTED. WILL
CONTINUE TO MONITOR OVER THE NEXT SEVERAL HOURS...AND WILL UPDATE IF
NECESSARY. IF CLOUDS DO STICK AROUND LONGER...SO TOO COULD THE
FLURRIES. OTHERWISE...LOADING IN THE LATEST OBSERVATIONS FOR
TEMPS...DEW POINTS...AND WINDS...THE REMAINDER OF THE FORECAST SEEMS
TO BE WELL ON TRACK WITH CURRENT CONDITIONS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 305 PM EST THU NOV 27 2014

CURRENT CONDITIONS ACROSS THE REGION FEATURE EXTENSIVE LOW LEVEL
CLOUD COVER WITH A COLD FRONT THAT MOVED THROUGH THE AREA LAST NIGHT
NOW PUSHING SOUTHEAST INTO THE MID APPALACHIAN RANGE. THIS FRONT HAS
BROUGHT SOME COLDER AIR THROUGH THE AREA ALONG WITH SOME ISOLATED
SNOW SHOWERS. UPSTREAM...ANOTHER COLD FRONT AIMS TO PUSH THROUGH THE
AREA. A MUCH DRIER FRONT LOOKS TO BE ON TAP WITH THIS ONE.
THOUGH...ANOTHER SHOT OF COLDER AIR AND EXTENSIVE CLOUD COVER WILL BE
WITH THIS FRONT. A FEW FLURRIES WILL BE POSSIBLE THIS EVENING BUT
WILL BE FAR FROM ACCUMULATING SNOWFALL. IN ADDITION TO THIS...THE
COLDER AIR FILTERING IN HAS RESULTED IN FALL TEMPS THROUGH THE DAY
TODAY AND HAVE TWEAKED DOWN THE HOURLY TEMPS. IN FACT...THE MAX TEMPS
FOR TODAY IN MANY LOCATIONS OCCURRED AROUND 11AM THIS MORNING AND AS
OF NOON...HOURLY TEMPS HAVE STEADILY DROPPED THROUGH THE AFTERNOON.
TONIGHT DRIER AIR FILTERING IN AND A VERY SHALLOW MOIST LAYER WILL
BRING AN END TO THE FLURRY ACTIVITY. THOUGH CLOUD COVER WILL STILL BE
AROUND AND SLOW TO DISSIPATE...BANKED UP AGAINST THE APPALACHIAN
RANGE IN NORTHWEST FLOW BECAUSE OF THIS...LOW TEMPS TONIGHT WILL DROP
INTO THE LOWER 20S. IF THERE HAPPENS TO BE ANY BREAKS IN THE CLOUD
COVER TONIGHT...AND THIS MAY BE IN THE NORTHWEST OR WEST...LOW TEMPS
WILL RAPIDLY PLUMMET INTO THE TEENS...POSSIBLY MIDDLE TEENS
ESPECIALLY WITH DEW POINTS TONIGHT AT MANY PLACES FORECASTED TO BE IN
THE TEENS.

THIS AIR MASS WILL MODIFY AS THE LOW LEVEL FLOW SWINGS AROUND TO THE
SOUTHWEST FOR FRIDAY AHEAD OF THE NEXT WAVE TO IMPACT THE AREA. WITH
THIS...HIGH TEMPERATURES WILL REBOUND BACK INTO THE UPPER 30S AND
LOWER 40S...THOUGH THIS IS STILL WELL BELOW NORMAL VALUES FOR THIS
TIME OF YEAR. WITH THIS...CLOUD COVER WILL BE ON THE INCREASE AS WILL
LOW LEVEL MOISTURE. THE CLOUD COVER APPEARS TO BE ENOUGH TO LESSEN
THE RIDGE VALLEY SPLIT THAT WOULD HAVE BEEN PRETTY SIGNIFICANT FRIDAY
NIGHT. THE LOW TEMPS ON FRIDAY NIGHT THOUGH WILL BE MUCH WARMER THAN
THURSDAY NIGHT. THE REST OF THE SHORT TERM LOOKS TO BE A DRY ONE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 305 PM EST THU NOV 27 2014

FORECAST CONFIDENCE REMAINS FAIRLY GOOD THROUGH THE WEEKEND...BUT
THERE IS LOW CONFIDENCE IN THE FORECAST AS WE MOVE INTO THE FIRST
WEEK OF DECEMBER. AT THE BEGINNING OF THE PERIOD THERE IS GOOD MODEL
AGREEMENT ON RISING 500 MB HEIGHTS WITH MID LEVEL ZONAL FLOW ACROSS
THE REGION...AND LOW LEVEL SOUTHERLY FLOW. AS A RESULT WE WILL SEE
WARMING TEMPERATURES THROUGH THE WEEKEND. ISENTROPIC LIFT WILL
GENERATE CLOUDS...AND MOST MODELS REMAIN INSISTENT AT GENERATING
LIGHT QPF ACROSS AT LEAST THE NORTH PART OF THE FORECAST AREA THIS
WEEKEND. HOWEVER...THERE IS ALSO GOOD MODEL AGREEMENT IN CONTINUING
TO SHOW THE MOISTURE REMAINING SHALLOW. SOME VERY LOW PROBABILITIES
WILL BE NEEDED FOR VERY LIGHT RAIN CHANCES FROM SATURDAY NIGHT INTO
SUNDAY IN THE NORTH AND WEST PART OF THE AREA...BUT NON MEASURABLE
SPRINKLES MAY BE THE MOST ANYONE SEES.

AS WE MOVE INTO NEXT WEEK THE MODELS BEGIN TO DIVERGE...AND BY LATE
IN THE WEEK THE GFS AND ECMWF OFFER COMPLETELY DIFFERENT SOLUTIONS.
FLOW REMAINS NEARLY ZONAL AT THE BEGINNING OF THE WORK WEEK. AT THE
SURFACE THERE IS GOOD MODEL AGREEMENT THAT A COLD FRONT WILL WORK
ITS WAY ACROSS THE AREA ON MONDAY. LATEST GUIDANCE FROM WPC SUPPORTS
THIS IDEA AS WELL. AS A RESULT RAIN CHANCES WILL INCREASE ACROSS THE
AREA SUNDAY NIGHT WITH A GOOD CHANCE OF RAIN ON MONDAY...BUT WITH
BASICALLY ZONAL FLOW CONTINUING IN THE WAKE OF THE FRONT THERE WILL
NOT BE A SIGNIFICANT COOL DOWN. THE EVOLUTION OF THE MEAN FLOW AT
MID WEEK AND BEYOND IS IN DOUBT AS GFS PERSISTS WITH A PRIMARILY
ZONAL FLOW PATTERN WITH CONTINUED WARM TEMPERATURES...WHILE THE
ECMWF HAS AN EASTERN NORTH AMERICAN TROUGH AND A WESTERN RIDGE BY
THURSDAY. CORRESPONDING 850 MB TEMPERATURES AND MOS GUIDANCE ARE IN
STARK CONTRAST WITH THE GFS WARMER AND THE ECMWF COOLER. THE
SUPERBLEND ACCOUNTS FOR SOME OF THE UNCERTAINTY...BUT IT SHOULD BE
NOTED THAT THE FORECAST FOR DAY 6 AND 7 HAVE VERY LOW CONFIDENCE AND
ACTUAL TEMPERATURES MAY BE QUITE A BIT WARMER OR QUITE A BIT COOLER.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1052 PM EST THU NOV 27 2014

A WEAK COLD FRONTAL BOUNDARY CONTINUES TO SLOWLY MAKE IT/S WAY ACROSS
KY. AS IT DOES...EXPECT CLOUD COVER TO CONTINUE ALONG AND JUST AHEAD
OF THE BOUNDARY. THESE CLOUDS ARE ACTUALLY PERSISTING LONGER THAN
WHAT WAS ORIGINALLY ANTICIPATED. IN ADDITION...LATEST FORECAST
SOUNDINGS WERE ON THE RIGHT TRACK WHEN THEY SHOWED CIGS LOWERING
LATE THIS EVENING. AS SUCH...KEPT MENTION OF BKN CLOUDS IN TAFS
THROUGH TOMORROW MORNING. IN ADDITION...LOWERED THE CIGS TO
PREDOMINATE MVFR CONDITIONS THROUGH THE REST OF THE NIGHT. IT IS
POSSIBLE THAT SOME VFR CONDITIONS WILL BREAK IN OCCASIONALLY...BUT
MVFR WILL CONTINUE TO BE THE PREVAILING CONDITION UNTIL THE DRY AIR
FINALLY STARTS WORKING IN. GIVEN THE LOW LEVEL CLOUDS...NW WINDS...AND
COLD CONDITIONS...SCATTERED AREAS OF FLURRIES CONTINUE TO FALL ACROSS
MUCH OF EASTERN KY...INCLUDING AT KSJS AND KJKL. THESE FLURRIES/SNOW
SHOWERS SHOULD POSE LITTLE AVIATIONAL IMPACTS...AND SHOULD NOT BE
CONTINUOUS. AS SUCH...KEPT MENTION OF SNOW OUT OF TAFS FOR THE
REMAINDER OF THE NIGHT. ONCE THE BOUNDARY MOVES THROUGH...AND THE
CLOUDS BEGIN ERODING...EXPECT VFR CONDITIONS TO TAKE HOLD THROUGH THE
DAY TOMORROW.

&&

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

$$

UPDATE...JMW
SHORT TERM...SHALLENBERGER
LONG TERM...SBH
AVIATION...JMW





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