Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 180124 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
824 PM EST WED DEC 17 2014

.UPDATE...
ISSUED AT 815 PM EST WED DEC 17 2014

HOURLY GRIDS HAVE BEEN ADJUSTED TO ACCOUNT FOR THE CLEARING SOUTH OF
THE INTERSTATE 64 CORRIDOR AND HOURLY TEMPERATURE TRENDS. SOME
LOCATIONS SUCH AS JKL AND SME AS WELL AS VALLEY LOCATIONS ARE RUNNING
BELOW THE PREVIOUS FORECAST SO THE FIRST FEW HOURS WERE TRENDED
ACCORDINGLY ALTHOUGH MIN T FOR THE REST OF THE NIGHT WAS UNCHANGED FOR
MOST LOCATIONS. LIGHT PRECIP OR VIRGA WILL APPROACH THE SW PART OF THE
CWA TOWARD DAWN...BUT WILL BE STRUGGLING TO OVERCOME SIGNIFICANT LOW
LEVEL DRY AIR.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 310 PM EST WED DEC 17 2014

19Z SFC ANALYSIS SHOWS HIGH PRESSURE STARTING TO MORE EFFECTIVELY
MOVE INTO THE AREA. THIS IS BEGINNING TO BREAK UP THE LOW LEVEL CLOUD
COVER ACROSS AT LEAST THE SOUTHERN HALF OF THE CWA. THESE CLOUDS HAVE
KEPT TEMPERATURES IN CHECK SO FAR TODAY WITH READINGS GENERALLY IN
THE MID TO UPPER 30S NORTH AND IN THE LOWER 40S IN THE SOUTHEAST
WHERE SOME EARLY SUNSHINE IS MAKING ITS PRESENCE FELT. DEWPOINTS HAVE
DRIED OUT THROUGH THE DAY AND ARE NOW IN THE UPPER 20S TO LOWER 30S.
WINDS HAVE BEEN RELATIVELY LIGHT GENERALLY FROM THE WEST AT 5 TO 10
KTS TODAY.

THE MODELS ARE NOW IN PRETTY GOOD AGREEMENT ALOFT THROUGH THE SHORT
TERM PORTION OF THE FORECAST. THEY ALL DEPICT THE CLOSED...BUT
PROGRESSIVE...UPPER LOW THAT WILL SKIRT EAST THROUGH THE LOWER GREAT
LAKES THIS EVENING AND OVERNIGHT. A BRIEF PERIOD OF RIDGING WILL
FOLLOW INTO THURSDAY MORNING FOR EASTERN KENTUCKY BEFORE A RATHER
DAMPENED WAVE MOVES THROUGH LATER IN THE DAY AND THAT NIGHT WITH
SOME WEAK MID-LEVEL ENERGY FLOWING INTO THE CONFLUENCE ZONE EAST OF
THE AREA. WITH THE GENERAL MODEL AGREEMENT HAVE FOLLOWED THE HIGH
RESOLUTION NAM12 AND HRRR MOST CLOSELY FOR WEATHER DETAILS.

SENSIBLE WEATHER WILL FEATURE A BRIEF TIME OF CLEARING THIS EVENING
AND INTO TONIGHT THAT SHOULD ALLOW FOR SOME DECENT RADIATIONAL
COOLING AND RIDGE TO VALLEY TEMPERATURE DIFFERENCES THROUGH MIDNIGHT.
THEREAFTER...HIGH AND MID LEVEL CLOUDS WILL RETURN TO THE AREA FROM
WEST TO EAST AND PUT A CAP ON THE COOLING...LIMITING FURTHER TERRAIN
DIFFERENCES FOR THE REST OF THE NIGHT. THESE CLOUDS WILL ATTEMPT TO
BRING SNOW TO THE SOUTHWESTERN PARTS OF THE AREA BEFORE DAWN...BUT IT
WILL HAVE TO OVERCOME THE DRYING TAKING PLACE ATTM. ACCORDINGLY...
HAVE UNDERCUT QPF AND POPS FROM THE NAM/MET FOR LATE TONIGHT INTO
THURSDAY MORNING. THE AREA OF LOW PRESSURE RESPONSIBLE FOR THE PCPN
THREAT WILL DAMPEN THROUGH THE MORNING AND FADE OUT BY AFTERNOON. FOR
THIS...HAVE LIMITED THE PCPN THREAT TO JUST FLURRIES AND SPRINKLES
FOR THE SECOND HALF OF THE DAY. ADDITIONAL MOISTURE WILL PASS BY TO
THE NORTH LATER THAT EVENING AND A FEW FLURRIES WILL BE POSSIBLE FROM
THIS ALONG WITH ANOTHER COOL NIGHT.

AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR THE T/TD/WIND
GRIDS FOR THE FIRST 20 HOURS OR SO BEFORE POPULATING WITH THE
SUPERBLEND THEREAFTER. MINOR ADJUSTMENTS WERE MADE FOR TERRAIN
EFFECTS BOTH TONIGHT AND THURSDAY NIGHT. AS FOR POPS...ENDED UP A BIT
UNDER THE MET NUMBERS AND CLOSER TO THE DRIER MAV ONES FOR TONIGHT
AND THURSDAY GIVEN THE DRY AIR THAT WILL BE IN PLACE.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 PM EST WED DEC 17 2014

FORECAST MODELS ARE IN GOOD AGREEMENT ON AN ACTIVE WEATHER PATTERN
WITH AT LEAST TWO SYSTEMS TO AFFECT US THROUGH THE PERIOD.

THE FIRST STORM OVER THE WEEKEND CONTINUES TO LOOK RATHER WEAK. A
LIGHT RAIN/SNOW MIX WILL MOVE INTO THE AREA OVERNIGHT FRIDAY NIGHT.
THIS WILL CHANGE TO ALL RAIN DURING THE DAY ON SATURDAY...FOLLOWED
BY PERHAPS BY A LITTLE MORE SNOW AS THE PRECIPITATION ENDS SATURDAY
NIGHT. THERE IS JUST NOT A LOT OF COLD AIR IN PLACE AND
PRECIPITATION LOOKS LIGHT SO ANY SNOW ACCUMULATIONS WILL BE VERY
LIGHT WITH THIS SYSTEM...IF ANY OCCUR AT ALL.

A MUCH MORE IMPRESSIVE STORM SYSTEM IS SHOWING UP IN THE COMPUTER
MODELS FOR THE MIDDLE OF NEXT WEEK...WITH DECENT AGREEMENT ON AN
IMPACTFUL SYSTEM JUST IN TIME FOR PEAK HOLIDAY TRAVEL. AN UPPER
LEVEL TROUGH WILL DIG IN OVER THE PLAINS EARLY IN THE WEEK AND
BECOME NEGATIVELY TILTED OVER THE OHIO VALLEY MID WEEK. THIS CAUSES
EXPLOSIVE DEEPENING OF A SURFACE LOW PRESSURE WHICH IS PROGGED TO
DEVELOP AND TRACK OVER US OR VERY CLOSE TO US ON ITS WAY NORTH TO
THE GREAT LAKES. THIS SYSTEM IS STILL WAY TOO FAR OUT IN THE FUTURE
TO PINPOINT EXACTLY WHAT TYPE OF WEATHER WE WILL BE DEALING
WITH...BUT RAIN...WIND AND SNOW ARE ALL ON THE TABLE FROM TUESDAY
THROUGH WEDNESDAY...AND POTENTIALLY BEYOND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 735 PM EST WED DEC 17 2014

THE LOW CLOUDS IN THE MVFR RANGE HAVE BROKEN UP AS DRIER AIR HAS
MOVED INTO THE AREA ALTHOUGH...ALTHOUGH THESE CONTINUE TO LINGER
ALONG THE INTERSTATE 64 CORRIDOR FROM LEX TO HTS INCLUDING SYM AND
IOB AND MAY LINGER AT SYM FOR THE FIRST FEW HOURS OF THE PERIOD...AND
CONFIDENCE IN TIMING OF CLEARING THERE IS LOW. ALSO...HIGH AND SOME
MID CLOUDS WILL START BUILDING IN OVER THE AREA FROM THE WEST AND
SOUTHWEST OVER THE FIRST 3 TO 8 HOURS OF THE PERIOD BUT THESE WILL
REMAIN IN THE VFR RANGE. THIS NEXT SYSTEM DOES BRING THE POTENTIAL
FOR SOME LIGHT SNOW TO THE SOUTHWEST PART OF THE AREA AFTER THE 10Z
TO 12Z PERIOD. DUE TO DRY LOW LEVEL AIR THIS WILL BRING A GRADUAL
LOWERING OF CIGS DOWN INTO THE MVFR RANGE BY THE LAST 12 HOURS OF THE
PERIOD...BUT VIS WILL LIKELY REMAIN MOSTLY IN THE VFR RANGE. LIGHT
WINS ARE ANTICIPATED THROUGH THE PERIOD.

&&

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

$$

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





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