Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 150625 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
225 AM EDT MON SEP 15 2014

.UPDATE...
ISSUED AT 225 AM EDT MON SEP 15 2014

BASED ON THE LATEST OBSERVATIONS...WENT AHEAD AND TWEAKED DOWN THE
LOW TEMPERATURES A BIT MORE...ESPECIALLY IN THE NORTHWEST PORTION OF
THE FORECAST AREA...WHERE SOME MID 40S LOOK LIKELY BY DAWN. DENSE FOG
ALSO CONTINUES TO EXPAND...AND THIS IS CURRENTLY HANDLED WELL WITH AN
SPS. WILL ONLY CONTINUE TO MONITOR TRENDS TO SEE IF WE NEED TO
INCLUDE A FEW MORE COUNTIES. UPDATES HAVE BEEN SENT.

UPDATE ISSUED AT 1138 PM EDT SUN SEP 14 2014

CLEARING SKIES...LIGHT WINDS AND DRY AIR AT THE SURFACE IS ALLOWING
NEAR IDEAL RADIATIVE COOLING CONDITIONS TONIGHT. TEMPERATURES HAVE
DROPPED TO...OR NEAR CROSSOVER THRESHOLDS AT SOME LOCATIONS AND TEMPS
HAVE SEVERAL HOURS OF COOLING REMAINING THROUGH THE OVERNIGHT. 11-3.9
CHANNEL SHOWING FOG HAS ALREADY BEGUN TO FORM AND KY MESONET STATIONS
ACROSS THE AREA ARE CONFIRMING THE FORMATION OF FOG. EXPECT THESE
TRENDS TO CONTINUE THROUGH THE REMAINDER OF THE NIGHT. AS A RESULT AS
BASED ON HOURLY TRENDS LOWERED OVERNIGHT LOWS FOR MUCH OF THE AREA
WHILE BEEFING UP FOG WORDING IN THE GRIDS AND ZONES. ALSO ISSUED A
SPECIAL WEATHER STATEMENT FOR LOCALLY DENSE FOG AND REFLECTED
CONCERNS IN THE HWO AS WELL. AREAS AT GREATEST RISK APPEAR TO BE
GENERALLY WITHIN THE DANIEL BOONE NATIONAL FORREST AND EASTWARD...
AND PARTICULARLY AREAS WHERE CLOUDS PREVENTED A FULL MIX OUT OF
BOUNDARY LAYER MOISTURE THROUGH THE DAY.

UPDATE ISSUED AT 755 PM EDT SUN SEP 14 2014

WITH THE EXCEPTION OF THE EXTREME SOUTHEASTERN FRINGE OF OUR CWA...
SKIES ARE CLEARING OUT. ADDING LOWER SFC DEW POINTS...SOLIDLY IN THE
50S AND SURFACE TEMPERATURES HAVE RESPONDED IN KIND IN MANY OF OUR
EASTERN LOCATIONS. GRIDS WERE RUNNING WELL BEHIND THE RAPID EVENING
COOL OFF IN PROGRESS IN THESE AREAS. ADJUSTED THE GRIDS TO MATCH UP
BETTER WITH THE DROP OFF. OTHERWISE NO MAJOR CHANGES TO THE FORECAST
PACKAGE...AT LEAST FOR NOW. OVERNIGHT LOWS LOOK QUITE CHILLY. WILL
REVISIT LOWS WITH NEXT UPDATE...ONCE MORE SOLID TRENDS HAVE BEEN
ESTABLISHED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 326 PM EDT SUN SEP 14 2014

CONDITIONS WILL REMAIN RATHER BENIGN THROUGH THE REST OF THE
AFTERNOON/EVENING TODAY UNDER HIGH PRESSURE. SOME LINGERING LOW
LEVEL MOISTURE ALONG THE S/SE BORDER WILL LEAD TO CONTINUED CLOUD
COVER AS A WEAK 850 DISTURBANCE PARKS OVER THE APPALACHIANS...AND
INTERACTS WITH A SURFACE FRONT ALONG THE ATLANTIC COAST. WHILE THESE
CLOUDS WILL PERSIST OVERNIGHT AND INTO THE DAY TOMORROW...THE REST
OF THE AREA SHOULD CLEAR OUT TONIGHT...AND ALLOW FOR STRONG
RADIATIONAL COOLING. WINDS WILL ALSO BE FAIRLY LIGHT...SO EXPECT
OVERNIGHT LOW TEMPS TO RETURN TO THE UPPER 40S AND LOW 50S...COOLEST
IN THE NORTH AND WARMEST IN THE SOUTH WHERE THE BEST CLOUD COVER
WILL BE SEEN.

A TRANSITION WILL BE IN STORE TOMORROW...AS WE AWAIT THE PASSAGE OF
A BOUNDARY THAT WILL MOVE IN FROM OUR NW DURING THE LATE
AFTERNOON/EVENING...AND INTO THE OVERNIGHT HOURS. NEAR SURFACE WINDS
WILL BECOME SOUTHERLY TOMORROW...AS CLOUDS INCREASE BY LATE MONDAY.
THIS PUSH OF WARMER AIR WILL ALLOW TEMPS TO MAKE IT A BIT HIGHER
THAN PREVIOUS DAYS...IN THE MID AND UPPER 70S. MODELS ARE COMING
INTO A BIT BETTER AGREEMENT AS THE PRECIP ASSOCIATED WITH THIS
BOUNDARY APPROACHES THE REGION. HOWEVER...THIS AGREEMENT BEGINS TO
DIMINISH ONCE THE PRECIP REACHES THE EASTERN KY REGION. THE GFS AND
GEM SHOW PRECIP MOVING INTO THE REGION DURING THE NIGHT MONDAY
NIGHT AND AFFECTING MUCH OF THE CWA...WHILE THE ECMWF SHOWS PRECIP
MOVING IN THROUGH 6Z BUT THEN DISSIPATING AFTER 6Z AS THE SYSTEM
LOSES STRENGTH. THE NAM SHOWS THE PRECIP AND BOUNDARY MOVING THROUGH
A BIT FASTER...BUT SEEMS TO TRY TO BREAK UP SOME OF THE BEST
COVERAGE...SO THAT IT IS A GOOD CROSS BETWEEN THE ECMWF AND GFS.
GIVEN THE LACK OF AGREEMENT...AS WELL AS THE LACK OF STRONG FORCING
AND DEEP MOISTURE...STUCK WITH GENERALLY SLIGHT POPS ACROSS THE
REGION AS IT MOVES THROUGH...WITH THE BEST CHANCES ACROSS THE
NORTHERN CWA AND ALONG THE HIGHER TERRAIN IN THE FAR EASTERN CWA.
WITH VERY LITTLE CAPE OR LAPSE RATES...THINK IT IS QUITE SAFE TO
CONTINUE WITH ONLY RAIN SHOWERS AT THIS POINT. ALSO...THE SYSTEM IS
MOVING SO FAST GIVEN THE 300MB JET STREAM MOTION OVER THE OHIO RIVER
VALLEY...THERE WILL BE LITTLE CONCERN OF SLOW MOVING OR TRAINING
CELLS PRODUCING ANY FLASH FLOOD THREATS.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM EDT SUN SEP 14 2014

THE MODELS ARE AGAIN IN GOOD AGREEMENT ALOFT FOR THE BULK OF THE
EXTENDED FEATURING A LARGE AND FILLING TROUGH OVER THE EASTERN HALF
OF THE NATION THROUGH FRIDAY MORNING. HOWEVER...THE SIMILARITIES
BREAK DOWN LATER FRIDAY AND INTO THE START OF THE WEEKEND AS ANOTHER
LARGE TROUGH DEVELOPS OVER THE NORTHERN PLAINS AND DIPS DEEPER INTO
THE HEART OF THE COUNTRY. THE 00Z ECMWF IS MORE AGGRESSIVE WITH THIS
THAN THE GFS AND STILL SEEMS A BIT SUSPECT...THOUGH TRENDING TOWARD
A MORE REASONABLE SOLUTION WHEN COMPARED TO ITS OUTLIER SOLUTION OF
24 HOURS AGO. THE DISCREPANCY BETWEEN THE GFS AND ECMWF BUILDS INTO
SUNDAY WHEN THE 00Z ECMWF HAS A DEEP TROUGH DIGGING INTO THE MIDWEST
WHILE THE GFS KEEPS ITS ENERGY MORE TO THE NORTHEAST AND INSTEAD
SHOWS RIDGING THROUGH THE GULF COAST STATES WITH MUCH HIGHER HEIGHTS
THROUGH KENTUCKY. THE 12Z ECMWF JUST COMING IN HAS TRENDED SHARPLY
TOWARD THE GFS SOLUTION WITH ITS CORE TROUGH CROSSING THE GREAT
LAKES RATHER THAN FURTHER TO THE SOUTHWEST. GIVEN THE TREND AND
BETTER SUPPORT WILL LEAN SLIGHTLY TOWARD THE 12Z ECMWF SOLUTION FOR
THE WEEKEND AFTER STICKING CLOSE TO A MODEL BLEND FOR THE FIRST PART
OF THE EXTENDED.

SENSIBLE WEATHER WILL FEATURE A PERIOD OF NEAR OR SLIGHTLY BELOW
NORMAL TEMPERATURES THROUGH THE EXTENDED AS A SERIES OF HIGH
PRESSURE AREAS BRUSH BY TO THE NORTH OF KENTUCKY. THESE HIGHS WILL
BE WELL NORTH OF A STALLED BOUNDARY TO THE SOUTH OF THE STATE
THROUGH THE REST OF THE WORK WEEK. RETURN FLOW ON THE BACKSIDE OF
THE ONE THAT MOVES OFF TO THE NORTHEAST FRIDAY WILL BRING MILDER
TEMPERATURES AND INCREASING MOISTURE TO EAST KENTUCKY JUST IN TIME
FOR THE WEEKEND. AN APPROACHING COLD FRONT FROM THE NORTHWEST WILL
THEN ATTEMPT TO TAKE ADVANTAGE OF THIS MORE HUMID AIR MASS TO
GENERATE SHOWERS...AND PERHAPS THUNDERSTORMS...AS IT SETTLES INTO
THE BLUEGRASS SUNDAY.

THE CR GRID LOAD AGAIN PROVED TO BE A GOOD START TO THE  EXTENDED
GRIDS...THOUGH AGAIN DID ADJUST THE POPS A TAD TOWARD MORE OF A
DIURNAL TREND EACH DAY AND ALSO TO GO A BIT DRIER THROUGH SATURDAY.
DID ALSO TWEAK THE LOW TEMPERATURE GRIDS A BIT EACH NIGHT TO REFLECT
AT LEAST SOME MINOR RIDGE AND VALLEY DIFFERENCES THAT WILL PROBABLY
BE LARGEST ON THURSDAY AND FRIDAY NIGHTS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 225 AM EDT MON SEP 15 2014

IFR OR WORSE FOG WILL EXPAND ACROSS MOST LOCATIONS THROUGH DAWN. THIS
INCLUDES MOST OF THE TAF SITES...WITH THE EXCEPTION OF KSYM...WHERE
SOME LIGHT WINDS WILL LIKELY HOLD THE FOG AT BAY. THE FOG WILL BURN
OFF BETWEEN 12 AND 14Z. CLOUDS WILL BE ON THE INCREASE DURING THE DAY
ON MONDAY AND INTO MONDAY EVENING OUT AHEAD OF AN APPROACHING COLD
FRONT...ALTHOUGH EXPECT THAT ANY CEILINGS WILL REMAIN VFR. WSW WINDS
OF 5 TO 10 KTS WILL ALSO ENGAGE DURING THE DAY.

&&

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

$$

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





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