Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 010603
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
103 AM EST SUN FEB 1 2015

.UPDATE...
ISSUED AT 103 AM EST SUN FEB 1 2015

FOR NOW...THE FORECAST ONLY NEEDED AN UPDATE TO THE TEMPERATURES AND
DEW POINTS. STILL SEEING SOME VERY DRY AIR IN SOME AREAS AND SLOW TO
RESPOND TO THE INCOMING MOISTURE. TRIED TO HIGHLIGHT THIS IN THE
UPDATE. BECAUSE OF THIS...NOT TOO CONCERNED ABOUT THE FORMATION OF
SLEET IN THE NORTH AT THIS POINT. STILL EXPECTING THE BEST CHANCE OF
MEASURABLE PRECIP TO ARRIVE LATER IN THE DAY SO THE FORECAST LOOKS
GOOD TO GO AND WILL LET THE CURRENT ZFP GO UNTIL THE MORNING PACKAGE
IS ISSUED.

UPDATE ISSUED AT 952 PM EST SAT JAN 31 2015

UPDATED TEMPERATURES A BIT TO REFLECT THE COLDER EASTERN VALLEYS. NOT
MANY OTHER CHANGES MADE AT THIS TIME. SOME QUESTION AS TO WHETHER THE
SLEET WILL MATERIALIZE AS MOST OF THE PRECIPITATION REPORTS REMAIN TO
THE NORTH...WITH THE FARTHEST SOUTH STATION REPORTING ANYTHING BEING
CINCINNATI. WILL MAINTAIN THE SLIGHT CHANCE OF SLEET ACROSS THE
NORTH...BUT CONFIDENCE REMAINS LOW THAT THIS WILL MATERIALIZE. LATEST
HRRR STILL SUPPORTS A MAINLY DRY PERIOD FOR SUNDAY MORNING WITH RAIN
APPROACHING THE WEST BY EARLY AFTERNOON.

UPDATE ISSUED AT 704 PM EST SAT JAN 31 2015

BASED UPON MODEL SOUNDINGS...THREAT FOR MEASURABLE PRECIPITATION
TONIGHT IS VERY LOW. IF ANYTHING DOES MANAGE TO MAKE IT TO THE
SURFACE...BEST CHANCES WOULD BE AROUND OR SHORTLY AFTER MIDNIGHT AS
THE WARM FRONT SLIDES ACROSS THE AREA. BEST CHANCES OF ANYTHING
HITTING THE GROUND WILL BE NORTH OF THE MOUNTAIN PARKWAY...AND WILL
BE WHERE A SLIGHT CHANCE WILL RESIDE. PRECIPITATION TYPE LOOKS TO BE
PRIMARILY SLEET...ALTHOUGH IF WE CAN WET BULB ENOUGH...SOME SNOW MAY
MIX IN. REGARDLESS...NOT MUCH OF A CONCERN OVERALL AS WE WILL REMAIN
SO DRY BELOW 10KFT. FREEZING RAIN WAS REMOVED AS THE BEST PERIOD OF
POPS WILL COINCIDE DURING THE TIME THAT TEMPERATURES ARE STILL ABOVE
FREEZING. ALSO SLOWED DOWN THE ONSET OF PRECIPITATION TOMORROW AS
MOST OF THE MORNING WILL REMAIN DRY WITH RAIN NOT MOVING INTO THE
AREA UNTIL THE AFTERNOON...AND LIKELY NOT UNTIL THE EVENING IN THE
EAST.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 414 PM EST SAT JAN 31 2015

A SHORTWAVE WILL INTENSIFY AS IT SHIFTS INTO THE NORTHERN PLAINS
OVERNIGHT...AND THEN STRENGTHENS AS IT EJECTS QUICKLY SE
INTENSIFYING FURTHER AS IT MOVES ACROSS THE OHIO VALLEY LATE SUNDAY
NIGHT AND THROUGH THE DAY MONDAY. AT THE SURFACE...A STRONG LOW
PRESSURE SYSTEM WILL DEVELOP AND QUICKLY MOVE ACROSS AND JUST NORTH
OF THE OHIO RIVER VALLEY DURING THE NIGHT SUNDAY. THE LATEST 12Z GFS
IS CONTINUING TO INTENSIFY THE LOW AND CARRY IT SLIGHTLY FARTHER
NORTHWARD. THIS WILL PULL THE DRY SLOT INTO OUR SE MORE...AND
PREVENT MOISTURE FROM MOVING IN QUITE AS FAST INTO THESE AREAS
DURING THE DAY SUNDAY.

THE LATEST RUNS OF THE MODELS SINCE OVERNIGHT ARE CONTINUING TO
BRING THE WARM NOSE FURTHER NORTH AS WELL /ASSOCIATED WITH THE
LOCATION OF THE WARM FRONT/...WHICH COULD LEAD TO SOME INCREASED
CHANCES OF FREEZING RAIN AND/OR SLEET...ASSUMING ANY PRECIP IS ABLE
TO MAKE IT PAST THE LOW LEVEL DRY LAYER. THAT BEING SAID...WENT
AHEAD AND INCLUDED MENTION OF SLEET AND FREEZING RAIN AS NEEDED BASED
ON TEMPS FOR SLIGHT CHANCE POPS. TEMPERATURES QUICKLY RISE WELL ABOVE
FREEZING BETWEEN 12 AND 15Z...SO EXPECT ANY PRECIP THAT FALLS AFTER
THIS POINT TO BE IN THE FORM OF RAIN. MODELS ARE ALL IN GOOD
AGREEMENT OF THE LINE OF PRECIP AND QPF AMOUNTS MOVING ACROSS EASTERN
KY SUNDAY AFTERNOON AND SUNDAY NIGHT...SO CONFIDENCE CONTINUES TO
GROW IN THIS AREA. THE COLD FRONT LOOKS TO PASS THROUGH THE CWA
BETWEEN 3 AND 10Z. BEHIND THE FRONT...DRY AIR WILL QUICKLY WORK IN
THE UPPER LEVELS...CUTTING OFF THE BEST QPF POTENTIAL. IT WILL ALSO
QUICKLY TURN THE RAIN OVER TO SNOW LATE IN THE NIGHT...WHICH WILL
TRANSITION US TO THE SNOW POTENTIAL IN THE BEGINNING OF THE EXTENDED
PERIOD.

SOME SLICK SPOTS WILL BE POSSIBLE ON THE ROADS TOMORROW
MORNING...ESPECIALLY BEFORE THE PRE-DAWN HOURS...AND IN LOCATIONS
WHERE SLEET AND FREEZING RAIN OCCURS. GIVEN THAT THERE ARE ONLY
SLIGHT CHANCE POPS IN AT THIS POINT...AND THERE IS STILL SOME
UNCERTAINTY WHETHER ANY PRECIP WILL ABLE TO MAKE IT PAST THE LOW
LEVEL DRY AIR...AS WELL AS WHEN AND WHERE EXACTLY THIS WILL
HAPPEN...WILL HOLD OFF ON ISSUING AN SPS AT THIS TIME. WILL CONTINUE
TO HIGHLIGHT IN THE HWO HOWEVER.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 425 PM EST SAT JAN 31 2015

THE MODELS ARE IN FAIRLY GOOD AGREEMENT ALOFT THROUGH THE START OF
THE EXTENDED FORECAST. THEY ALL TAKE A SHARP TROUGH THROUGH THE
SOUTHERN APPALACHIANS EARLY MONDAY AND OFF THE EAST COAST BY THAT
EVENING. IN ITS WAKE...ANOTHER WEAKER WAVE QUICKLY PASSES OVER THE
REGION INTO TUESDAY MORNING. ADDITIONAL ENERGY SLIPS THROUGH THE
AREA BY WEDNESDAY MORNING. AT THIS POINT...THE MODELS START TO
DIVERGE WITH THE ECMWF PUSHING A DEEPER TROUGH THROUGH THE GREAT
LAKES THAN THE GFS...SINKING ITS INFLUENCE TOWARD KENTUCKY INTO
THURSDAY MORNING. THIS WAVE ALSO MOVES QUICKLY TO THE COAST BY THAT
EVENING LEAVING WEAKER ENERGY BEHIND OVER THE MIDWEST THAT TAKES THE
FORM OF ANOTHER TROUGH IN RESPONSE TO A BUILDING SOUTHWESTERN RIDGE.
WITH THIS TROUGH THE GFS IS SIGNIFICANTLY STRONGER THAN THE ECMWF AS
IT PASSES THROUGH THE DEEP SOUTH. FAST NORTHWEST FLOW FOLLOWS FOR
EASTERN KENTUCKY INTO THE DAY SATURDAY WITH EXTRA POCKETS OF ENERGY
DRIFTING BY THROUGH THE EVENING. GIVEN THE GOOD MODEL AGREEMENT
EARLY...HAVE FAVORED A MODEL BLEND THROUGH THURSDAY WITH THE ECMWF
LOOKING MORE REASONABLE THEREAFTER.

SENSIBLE WEATHER WILL FEATURE AN ARCTIC BOUNDARY PASSING THROUGH
EASTERN KENTUCKY EARLY MONDAY MORNING WITH WRAP AROUND MOISTURE AND
UPSLOPE FLOW AFFECTING OUR HIGHER TERRAIN THROUGH THE MORNING AND
INTO THE AFTERNOON...DRYING OUT FROM WEST TO EAST. THE TIMING OF THE
ARCTIC AIR ARRIVAL WILL BE KEY TO OUR HIGHS ON MONDAY WITH FALLING
TEMPERATURES THROUGH THE DAY. FOLLOWING A BLEND HAVE BROUGHT
FREEZING TEMPS TO THE WESTERN PARTS OF THE AREA BY DAWN WITH THE
REST OF THE EASTERN KENTUCKY FALLING BELOW 32 DEGREES WITHIN A
COUPLE OF HOURS. LINGERING MOISTURE AND UPSLOPE FLOW WILL RESULT IN
ACCUMULATING SNOW FOR MUCH OF THE AREA MAXIMIZED OVER THE FAR EAST
WHERE A COUPLE OF INCHES WILL BE POSSIBLE ON THE HIGHEST RIDGES NEAR
VIRGINIA. THE REST OF THE AREA CAN EXPECT AN INCH OR LESS WITH
HIGHEST AMOUNTS FOUND ON THE RIDGES. HIGH PRESSURE MOVES IN AND COLD
TEMPERATURES FOLLOW WITH LOWS BACK IN THE TEENS THAT NIGHT. AFTER
THE HIGH MOVES OUT THE NEXT ITERATION OF THE ARCTIC BOUNDARY SLIDES
THROUGH WEDNESDAY INTO THURSDAY WITH ADDITIONAL LIGHT SNOW EXPECTED.
THE PREFERRED ECMWF IS MUCH DRIER WITH THIS THAN THE GFS KEEPING ITS
SNOW TOTALS TO A MINIMUM. ANOTHER HIGH FOLLOWS CLEARING OUT THE SNOW
AND DRYING OUT THE AREA. THE ARCTIC FRONT THEN LIFTS BACK NORTH AND
HOLDS THERE...OVER THE MIDDLE AND NORTHERN PARTS OF THE OHIO
VALLEY...THROUGH SATURDAY.

THE CR GRID LOAD PROVIDED A DECENT START FOR THE EXTENDED FORECAST
WITH CHANGES MAINLY MADE EARLY ON FOR UPSLOPE AND TERRAIN DRIVEN
SNOW AND ALSO SOME CHANGES TO BETTER REFLECT THE LATEST ECMWF
SOLUTION IN THE LATTER PARTS OF THE FORECAST. ALSO...MADE SOME
TYPICAL RIDGE AND VALLEY TEMPERATURE ADJUSTMENTS FOR LOWS EACH
NIGHT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 103 AM EST SUN FEB 1 2015

EXPECT MID AND UPPER LEVEL CLOUD COVER TO CONTINUE TO MOVE INTO THE
AREA TONIGHT AND INTO THE DAY ON MONDAY. VFR CONDITIONS WILL PERSIST
THROUGH THIS TIME AS WELL. BY MONDAY AFTERNOON 18Z TO 22Z...CIGS WILL
DROP AS HEAVIER RAINFALL BEGINS TO MOVE INTO THE AREA ALONG WITH
VISIBILITY. IFR AND BELOW CONDITIONS WILL BE AT ALL THE TAF SITES
AFTER 00Z WITH MODERATE TO HEAVY RAINFALL MOVING THROUGH. WINDS WILL
BE LIGHT DURING THE FIRST HALF OF THE TAF PERIOD BEFORE SHIFTING
AROUND TO THE SOUTH AND SOUTHWEST AND GUSTING UP TO 20 KNOTS AT
TIMES.

&&

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

$$

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





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