Area Forecast Discussion
Issued by NWS Jackson, KY

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674
FXUS63 KJKL 100129 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
829 PM EST TUE FEB 9 2016

.UPDATE...
ISSUED AT 822 PM EST TUE FEB 9 2016

HOURLY GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT OBSERVATIONS
AND RADAR TRENDS. YET ANOTHER IN A SERIES OF DISTURBANCES IN NW
FLOW IS MOVING THROUGH THE OHIO VALLEY REGION. CONTINUED COLD AIR
ADVECTION SHOULD SERVE TO STEEPEN LAPSE RATES A BIT MORE OVER THE
NEXT FEW HOURS DESPITE LOSS OF DAYTIME HEATING. THIS SHOULD LEAD
TO AN INCREASE IN COVERAGE AND INTENSITY OF SNOW SHOWERS IN
SEVERAL AREAS AND EVIDENCE OF THIS APPEARS TO BE ON RADAR WITH
HIGHER RETURNS NOW SHOWING UP ALONG AND WEST OF THE ESCARPMENT IN
PORTIONS OF THE NW COUNTIES. WINDS THROUGH THE LOWER LEVELS SHOULD
AVERAGE A BIT MORE WEST TO NORTHWEST OVER THE NEXT 5 TO 8
HOURS...AND SHOULD ALSO SUPPORT CONTINUE SNOW SHOWERS AND FLURRIES
AND THE SLIGHT INCREASE IN INTENSITY AND COVERAGE NOTED ABOVE AS
WELL. POPS WERE ADJUSTED A BIT TO INDICATE THIS FOR THE OVERNIGHT
AND THE PREVIOUSLY FORECAST MIN TEMPERATURES LOOK ON TARGET.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 330 PM EST TUE FEB 9 2016

WATER VAPOR AND MESOANALYSIS STILL DEPICTING A DEEP AND BROAD
AREA OF CYCLONIC FLOW ACROSS MUCH OF THE EASTERN CONUS. THIS IS
LEADING TO SNOW SHOWERS AND MAYBE EVEN SNOW SQUALLS AT TIMES.
GIVEN THIS GENERAL FLOW AND THE OPEN GREAT LAKE WATERS SOME OF OUR
MOISTURE IS COMING OFF THE LAKES. MOST OF THE SNOW SHOWERS WILL
REMAIN LIGHT...BUT OF FEW OF THESE SHOWERS COULD BE MODERATE TO
EVEN HEAVY AT TIMES. THIS WILL STILL LEAD TO ADDITIONAL LIGHT
ACCUMULATIONS AND REDUCTIONS IN VISIBILITY. OVERALL GIVEN THIS
WILL OPT TO LEAVE OUR CURRENT ADVISORY AS IS.

THE OTHER STORY WILL BE THE CONTINUAL COLD AIR ADVECTION
OVERTIME...WE WILL SEE TEMPERATURES DROPPING INTO THE MID TEENS
OVERNIGHT. BASED ON THE SOUNDINGS WE COULD SEE OCCASIONAL GUSTS
AT TIMES WITH DECENT MIXING...SO DID KEEP SOME GUSTY WINDS AT
TIMES TONIGHT. NOW FOR WEDNESDAY THIS BROAD LOW WILL BEGIN TO EXIT
EAST AND THIS WILL AID IN WAINING THE SNOW SHOWERS THROUGH THE DAY
FROM SW TO NE. THE CLOUDS SHOULD ALSO BEGIN EXITING THE REGION IN
THE SAME FASHION...TEMPS WILL REMAIN WELL BELOW NORMAL WITH HIGHS
TOPPING OUT IN THE LOW 20S AND EVEN TEENS IN SOME OF THE HIGHER
TERRAIN. THE POTENTIAL FOR CLEARING SKIES COULD LEAD TO A VERY
COLD NIGHT THURSDAY NIGHT...HOWEVER THERE IS SOME UNCERTAINTY ON
CLEARING IN THE SW DUE TO ANOTHER WAVE. THERE REMAINS A FAIR
AMOUNT OF UNCERTAINTY ON THE TRACK AND IF WE GET ANY CHANCE OF
PRECIP IN THAT AREA...RIGHT NOW KEEPING IT DRY. EITHER WAY RIGHT
NOW TEMPS LOOK TO DROP INTO THE SINGLE DIGITS.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 455 PM EST TUE FEB 9 2016

THE MODELS ARE IN GOOD AGREEMENT ALOFT AT LEAST THROUGH THE START
OF THE UPCOMING WEEKEND AS THEY ALL DEPICT ONE DEEP NORTHEASTERN
TROUGH REPLACED BY ANOTHER. THE AGREEMENT DOES BREAK DOWN INTO
SATURDAY EVENING WITH THE GFS SLIGHTLY DEEPER WITH THE DEPARTING
EASTERN TROUGH WHILE THE ECMWF IS SLOWER...BUT ALSO WEAKER. FOR
KENTUCKY...BENIGN NORTHWEST FLOW FOLLOWS FOR SUNDAY WITH EVEN
SOME RIDGING AT MID LEVELS LATE IN THE DAY. THE LATEST ECMWF HAS
BACKED OFF ITS EARLIER IDEA OF A MODERATELY STRONG TROUGH PLOWING
INTO THE OHIO VALLEY SUNDAY NIGHT IN FAVOR OF A SLOWER VERSION
BUILDING THROUGH THE DAY MONDAY...MORE IN LINE WITH...BUT SLOWER
AND STRONGER...THE GFS. THE 12Z ECMWF CONTINUES TO BE MORE
AGGRESSIVE WITH THIS PATTERN INTO TUESDAY AS IT DIGS ITS WAVE DOWN
INTO THE TENNESSEE VALLEY IN TANDEM WITH A STRONG ONE ALONG THE
GULF COAST. THE LAST TWO RUNS OF THE ECMWF IS SUGGESTING A MORE
DYNAMIC SITUATION THAN THE GFS AND ITS FLATTER TROUGH. IN
GENERAL...WILL FAVOR A MODEL BLEND THROUGH THE FIRST PART OF THE
WEEKEND WITH A LEAN TOWARD THE MORE AMPLIFIED ECMWF FOR THE START
OF THE NEW WEEK.

SENSIBLE WEATHER WILL FEATURE A MODERATING AREA OF HIGH PRESSURE
PASSING OVER EASTERN KENTUCKY ON THURSDAY WITH A WEAK SFC WAVE
MOVING THROUGH FRIDAY MAKING ANOTHER SHOT OF SNOW SHOWERS
POSSIBLE FOR OUR AREA FROM FRIDAY INTO SATURDAY MORNING. ANOTHER
COLDER AREA OF HIGH PRESSURE FOLLOWS THIS SETTING THE STAGE FOR A
VERY CHILLY NIGHT INTO SUNDAY MORNING. THE NEXT WEATHER MAKER WILL
MOVE INTO THE MID MISSISSIPPI VALLEY LATER THAT DAY WITH SNOW
SHOWERS A POSSIBILITY FOR KENTUCKY THAT NIGHT AND INTO MONDAY.
GOING MORE ALONG WITH THE ECMWF SOLUTION...A MORE ROBUST SFC WAVE
WILL PASS THROUGH THE TENNESSEE VALLEY...PERHAPS STRENGTHENING
ALONG THE GULF COAST...ON MONDAY. IN THIS SCENARIO...ACCUMULATING
SNOW...POSSIBLY RATHER WET...WILL BE A CONCERN. THE GFS...BY
CONTRAST...MOVES THE SFC REFLECTION OF ITS WEAK MID LEVEL TROUGH
THROUGH KENTUCKY SUNDAY NIGHT INTO MONDAY WITH A LESSER CHANCE OF
ACCUMULATING SNOW. GIVEN THE LARGE MODEL DIFFERENCES AT THESE
LATTER TIME STEPS CONFIDENCE IS MUCH LOWER THAN AVERAGE...BUT ONE
THING IS CERTAIN -- THE GROUND HOG WAS WRONG.

ADJUSTED THE GRIDS FROM THE CR INIT TO ACCOUNT FOR SMALL RIDGE TO
VALLEY TEMPERATURE DIFFERENCES EACH NIGHT. ALSO TWEAKED THE POP
GRIDS LATER IN THE PERIOD TO REFLECT A FORECAST CLOSER TO THE
LATEST AND MORE EXTREME ECMWF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 739 PM EST TUE FEB 9 2016

SCATTERED TO NUMEROUS SNOW SHOWERS ARE STILL OCCURRING THIS
EVENING AND SHOULD PERSIST THROUGH THE NEXT 12 TO 15
HOURS...ALTHOUGH THE HEAVIEST OF THESE ARE ANTICIPATED THROUGH
9Z. MOST SITES WILL AVERAGE THE LOWER END OF THE VFR RANGE TO MVFR
WITH IFR CONDITIONS FROM TIME TO TIME IN ANY HEAVIER SNOW SHOWERS.
DURING THE FINAL 12 HOURS OF THE PERIOD...SNOW SHOWERS AND
FLURRIES SHOULD BEGIN TO DIMINISH AND EXIT FROM WEST TO EAST.
WINDS WILL AVERAGE OUT OF THE WEST AT 10KT OR LESS...ALTHOUGH
GUSTS IN THE 15 TO 20 KT RANGE ARE POSSIBLE IN HEAVIER SNOW
SHOWERS.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.

&&

$$

UPDATE...JP
SHORT TERM...DJ
LONG TERM...GREIF
AVIATION...JP



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