Heavy Snow in Kentucky, December 18 to 19, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1237 PM EST FRI DEC 18 2009

.SHORT TERM.../THE REST OF TODAY/

NOT MANY CHANGES TO THE CURRENT FORECAST AS THE STORM LOOKS ON TRACK
AT THIS POINT. CURRENT OBS SHOW THAT RAIN HAS COMMENCED ALONG THE
TENNESSEE AND KENTUCKY BORDERS WITH A FEW REPORTS OF SOME FLAKES
MIXED IN. HIGHER RIDGES ARE STAYING COOLER AND FEEL THIS COULD HAVE
AN IMPACT ON HOW MUCH VALLEYS SEE VERSUS THE RIDGE TOPS. EXPECT
PRECIPITATION TO GRADUALLY SPREAD NORTHWARD THROUGH THE REST OF THE
LATE MORNING AND EARLY AFTERNOON AND SLOWLY OVERCOMING THE DRY LOWER
LEVELS. MOST PRECIPITATION SHOULD START OUT AS RAIN OR A RAIN SNOW
MIX AND CHANGE TO ALL SNOW BETWEEN 4 AND 7 PM. AREAS IN THE EXTREME
SOUTHEAST SHOULD SEE THE CHANGEOVER BY MID AFTERNOON. AT THIS POINT
FEEL THE BIGGEST IMPACTS WILL NOT BE SEEN UNTIL AFTER 5 PM. MODELS
HAVE BEEN FAIRLY CONSISTENT WITH OVERALL TRACK OF THE SYSTEM...
HOWEVER THERE ARE STILL WIDE RANGES OF DIFFERENCE BETWEEN QPF
AMOUNTS. WILL CONTINUE TO GO BELOW THE WETTEST NAM...HOWEVER IT HAS
GAINED SOME SUPPORT FROM CANADIAN/UKMET. THIS HAS RAISED SOME CONCERN
ABOUT MEETING WARNING CRITERIA IN OUR NORTHWEST COUNTIES. WILL
CONTINUE TO MONITOR LATEST TRENDS AND RE- CONSIDER A POSSIBLE UPGRADE
TO WINTER STORM WARNING FROM JACKSON TO FLEMING COUNTY WITH THE
AFTERNOON PACKAGE. AT THIS POINT THE HIGH END OF THE 2 TO 4 INCH
RANGE SEEMS A GOOD POSSIBILITY. THE TIME FRAME COULD BE A BIT LATER
WITH THE HEAVIEST SNOW FALLING BETWEEN MIDNIGHT AND MID MORNING ON
SATURDAY.

ELSEWHERE IN THE WINTER STORM WARNING...WIDESPREAD 4 TO 6 INCHES
STILL SEEMS REASONABLE WITH THE HIGHER AMOUNTS ON RIDGE TOPS AND THE
LOWER AMOUNTS IN THE VALLEYS. STILL EXPECT THE HIGHEST ACCUMULATION
TOTALS OF 5 TO 10 INCHES IN THE EXTREME SOUTHEAST AND EAST KENTUCKY
WITH UP TO A FOOT ON THE HIGHEST PEAKS.

THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...

/TODAY THROUGH SUNDAY/

...WINTER WEATHER WARNINGS AND ADVISORIES TO BE ISSUED FOR THE AREA
STARTING LATE THIS AFTERNOON...

07Z SFC ANALYSIS SHOWS HIGH PRESSURE TO OUR NORTHEAST QUICKLY
RETREATING FURTHER THAT WAY IN THE FACE OF A DEVELOPING LOW PRESSURE
CENTER INBOUND FROM THE SOUTHWEST. HIGH CLOUDS FROM THIS HAVE
OVERSPREAD EAST KENTUCKY AND SERVED TO LIMIT THE RIDGE TO VALLEY
TEMPERATURE SPLIT OVERNIGHT TO JUST A 5 TO 10 DEGREES SPREAD. IN THE
FAR SOUTH HIGHER DEWPOINTS HAVE KEPT TEMPS UP THERE...AS WELL.
DEWPOINTS VARIED FROM THE MID 30S AT MIDDLESBORO ALONG THE TENNESSEE
BORDER TO THE TEENS IN THE NORTHWEST PORTIONS OF THE CWA. IT IS ALSO
INTERESTING TO NOTE THAT BLACK MOUNTAIN IS RUNNING AT 35 DEGREES WITH
A RELATIVELY MOIST DEWPOINT OF 22 DEGREES.

THE MODELS HAVE GELLED ON A SOLUTION IN THE UPPER PATTERN THAT
FEATURES A PHASING OF THE NORTHERN STREAM AND SOUTHERN STREAMS OVER
THE LOWER MISSISSIPPI VALLEY AMPLIFYING A TROUGH CROSSING FROM THE
PLAINS INTO THE OHIO VALLEY TONIGHT. THE NAM IS A LITTLE STRONGER
WITH THIS UPPER TROUGH BY 18Z SATURDAY THAN THE GFS AND ALSO FURTHER
AMPLIFIES IT MORE AS IT MAKES IT TO THE DELMARVA AREA EARLY SUNDAY.
BELIEVE THAT MUCH OF THESE DISCREPANCIES STEM FROM THE DIFFERENCE IN
RESOLUTION AND ACCORDINGLY HAVE CHOSEN TO FOLLOW THE SOLUTION FROM
THE NAM12 FOR WEATHER SPECIFICS RATHER THAN THE ONES FROM THE COARSER
GFS AND ECMWF. IN ADDITION...THE NAM SPECIFICS ARE MORE
CLIMATOLOGICALLY FAVORED WITH RESPECT TO THE TRACK AND AMPLIFICATION
OF THE SFC LOW. FOR SUNDAY...EAST KENTUCKY WILL REMAIN UNDER THE
INFLUENCE OF A BROAD AND EXTENSIVE TROUGH THROUGH THE NORTHEAST THIRD
OF THE NATION.

SENSIBLE WEATHER WILL FEATURE A POTENT NORTHERN GULF LOW CROSSING
THROUGH THE SOUTHEAST AND AMPLIFYING AS IT MOVES TO THE CAROLINA
COAST LATER TONIGHT. FROM THERE IT WILL RIDE UP THE SOUTHEAST COAST
BOMBING FURTHER...OFF OF THE JERSEY SHORE...BY THAT EVENING. WITH
THIS...COPIOUS AMOUNTS OF MOISTURE WILL BE PUSHED INTO FAR EAST
KENTUCKY LATER TODAY WITH DYNAMIC COOLING LIKELY LEADING TO AN EARLY
CHANGEOVER FROM RAIN TO SNOW LATE THIS AFTERNOON. THE MOISTURE WILL
EXPAND AND BUILD NORTHWEST AS THE SFC LOW PASSES AND DEEPENS. AIDED
BY THE LOSS OF SOLAR INSOLATION THE MODERATE TO HEAVY PCPN WILL
CHANGE TO ALL SNOW OVER THE BULK OF THE AREA DURING THE EARLY EVENING
HOURS. DESPITE THE RELATIVELY WARM GROUND TEMPERATURES THE HEAVINESS
OF THE SNOW WILL OVERCOME THE MELTING DURING THE EVENING HOURS AND
START TO PILE UP...PARTICULARLY SOUTHEAST OF AN INEZ TO JACKSON TO
LONDON LINE. EXPECT THE VALLEYS TO STAY AS RAIN THE LONGEST INTO THE
EVENING BUT ONLY FOR AN ADDITIONAL COUPLE OF HOURS AT MOST...BUT IT
WILL BE ENOUGH TO CUT INTO THEIR SNOW TOTALS.

THE SNOW FROM THIS EVENT WILL BE MOST INTENSE AND HEAVY DURING THE
EVENING AND INTO THE OVERNIGHT. IN ADDITION...WITH TEMPERATURES NOT
FAR FROM FREEZING THE SNOW WILL BE A HEAVY AND WET VARIETY THAT WILL
CERTAINLY WEIGH ON THE TREES AND POWER LINES...SO THIS IS A DANGEROUS
SITUATION THAT WILL BE HIGHLIGHTED IN THE WSW TO BE ISSUED LATER THIS
MORNING. THE INTENSITY OF THE SNOWFALL WILL BE ENHANCED BY A SERIES
OF JET STREAKS CROSSING THE REGION TONIGHT. DURING THE LATE AFTERNOON
A COUPLE STRUCTURE FROM A DEPARTING ONE OVER THE OHIO VALLEY AND
ANOTHER ACCOMPANYING THE LOW AS IT TRACKS EAST NORTHEAST TO OUR
SOUTH. IN ADDITION...A TRAILING STREAK WILL DIVE INTO THE TENNESSEE
VALLEY LATER IN THE EVENING ADDING ITS DIVERGENCE AND LIFT TO THE
EQUATION INTO EARLY SATURDAY MORNING. WHILE CERTAINLY THE WORST OF
THE SNOWFALL WILL BE PUSHING EAST BY SATURDAY MORNING...PLENTY OF
MOISTURE WILL REMAIN OVER THE OHIO VALLEY AND COMBINED WITH UPSLOPE
FLOW AND ADDITIONAL UPPER LEVEL SUPPORT FROM THE PASSING TROUGH SNOW
WILL CONTINUE TO FALL...JUST AT A LIGHTER INTENSITY. THIS WILL
CONTINUE THROUGH THE DAY AND INTO SATURDAY NIGHT BEFORE TAPERING FOR
GOOD FROM WEST TO EAST EARLY SUNDAY.

WHEN ALL IS SAID AND DONE...EXPECT TO SEE A GOOD 2 TO 4 INCH
COVERING OF SNOW OVER OUR WESTERN COUNTIES WHERE A WINTER WEATHER
ADVISORY WILL BE HOISTED...4 TO 6 INCHES FURTHER EAST WHERE A WARNING
WILL BE ISSUED WHILE IN THE COUNTIES ALONG THE VIRGINA BORDER 6 TO 10
INCHES WILL OCCUR. THE ADVISORIES AND WARNINGS WILL ALL START AT 4 PM
EST TODAY AND CONTINUE UNTIL 6 AM EST SUNDAY...HOWEVER...THE WORST OF
THE SNOW WILL DEFINITELY OCCUR THIS EVENING AND INTO THE OVERNIGHT
AND THIS WILL FACT BE PROMINENT IN THE DISCUSSION PORTION OF THESE
PRODUCTS.

FOLLOWED THE RAW NUMBERS FROM THE NAM12 FOR TEMPERATURES THROUGH
SATURDAY MORNING WITH SOME FURTHER ADJUSTMENTS FOR ELEVATION AND
EXPECTED SNOW COVER. THEREAFTER...THE MAV MOS SEEMED MOST REASONABLE
AND WAS FOLLOWED AGAIN WITH MINOR ADJUSTMENTS FOR SNOW COVER AND
ELEVATION. AS FOR POPS...ALL GUIDANCE WAS PRETTY HIGH AND MATCHED UP
WELL WITH OUR POPS THROUGH THE NEXT FOUR PERIODS AND THEN THE MORE
MOIST MET WAS FOLLOWED ON SUNDAY AS ITS NUMBERS BETTER REFLECTED THE
LINGERING UPSLOPE SNOW SHOWERS IN OUR EAST.

.LONG TERM.../SUNDAY NIGHT THROUGH THURSDAY/

BROAD TROUGHING ACROSS THE THE EASTERN CONUS WILL TRANSITION TO
ZONAL FLOW...BEFORE ANOTHER DEEPENING TROUGH TAKES SHAPE ACROSS THE
WESTERN CONUS TOWARDS THE MIDDLE OF THE WEEK.

FOR EASTERN KENTUCKY...COLD AND ADDITIONAL SNOW SHOWERS WILL
CONTINUE SUNDAY NIGHT INTO MONDAY AS A SHORT WAVE TROUGH AND
ACCOMPANIED WEAKER SURFACE LOW PRESSURE TRACK NORTH OF THE AREA.
RIDGING WILL THEN BRING DRY WEATHER TO THE AREA FROM MONDAY NIGHT
THROUGH EARLY WEDNESDAY MORNING.

ANOTHER SIGNIFICANT SYSTEM WILL THEN THREATEN THE AREA LATER IN THE
DAY ON WEDNESDAY AND INTO THURSDAY. THE LATEST SUITE OF MODEL
GUIDANCE SHOWS A LITTLE LESS SPREAD IN THE UPPER LEVEL AND SURFACE
PATTERNS...ALTHOUGH DETAILS CONTINUE TO BE VERY UNCERTAIN AT THIS
TIME. BOTH THE LATEST 00Z RUNS OF THE CANADIAN AND ECMWF HAVE
TRENDED MORE TOWARD SHARPER DIGGING OVER THE WESTERN CONUS...CLOSER
TO THE LATEST GFS IDEA. WHILE THE GFS REMAINS ON THE EXTREME SIDE
WITH THE DIGGING AND THE INTENSITY OF THE ASSOCIATED SURFACE
REFLECTION...ALL GUIDANCE APPEARS TO SHOW MORE MODIFYING
TEMPERATURES AND MORE OF A RAIN DOMINATED PRECIPITATION TYPE HERE.
ACCORDINGLY...HAVE ADJUSTED TEMPERATURES UP...ALTHOUGH NOT AS
EXTREME AS THE GFS. LEFT THE CURRENT GOOD CHANCE POPS FOR WEDNESDAY
NIGHT INTO THURSDAY INTACT.

&&

.AVIATION.../18Z TO 18Z/...UPDATED

VERY FEW CHANGES NECESSARY TO TAFS OR GRIDS ATTM. CEILINGS ARE
GRADUALLY LOWERING AS RAIN JUST BEGAN AT SME/LOZ IN LAST COUPLE OF
HOURS AND IS JUST ALOFT AT JKL AT 1730Z. PRECIPITATION IS WIDESPREAD
ON RADAR WHICH WILL SATURATE LOWER LEVELS AND CLOUDS/VISIBILITY WILL
CONTINUE GOING DOWN THIS AFTERNOON AND THROUGH TONIGHT. SNOW LEVELS
WILL GRADUALLY DECREASE IN ELEVATION AS WELL WHILE SPREADING FROM
SOUTHWEST TO NORTHEAST.

IFR CONDITIONS UNDER LOW CEILINGS WILL PERSIST THROUGH AT LEAST SAT
NIGHT IN HIGH MOISTURE AND UPSLOPE FLOW. A BREAK ON SUNDAY IS EXPECTED
AS LOW LEVEL (BELOW 5 KFT) FLOW TURNS MORE WESTERLY AND DRIER AIR
ARRIVES.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR KYZ044-050>052-058>060-068-069-079-083-104-106-108-
111.

WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY
FOR KYZ080-084>088-107-109-110-112>120.

&&

SHORT TERM...GREIF/SCHOETTMER
LONG TERM....GEOGERIAN
AVIATION...GV

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
108 PM EST FRI DEC 18 2009

KYZ080-084>086-107-109-110-112>117-119-192115-
LAUREL-MCCREARY-WHITLEY-KNOX-JOHNSON-MAGOFFIN-FLOYD-BREATHITT-KNOTT-
OWSLEY-PERRY-CLAY-LESLIE-MARTIN-
INCLUDING THE CITIES OF...LONDON...WHITLEY CITY...CORBIN...
WILLIAMSBURG...BARBOURVILLE...PAINTSVILLE...SALYERSVILLE...
PRESTONSBURG...JACKSON...HINDMAN...BOONEVILLE...HAZARD...
MANCHESTER...HYDEN...INEZ
108 PM EST FRI DEC 18 2009

...WINTER STORM WARNING IN EFFECT FROM 4 PM THIS AFTERNOON TO 6 AM
EST SUNDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN KENTUCKY.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

A DEVELOPING WINTER STORM WILL BRING SNOW TO EAST KENTUCKY BEGINNING
AS EARLY AS LATE THIS AFTERNOON. THE HEAVIEST SNOW WILL FALL THIS
EVENING AND OVERNIGHT. ACCUMULATIONS OF 2 TO 5 INCHES OF SNOW ARE
EXPECTED DURING THIS PERIOD.

THE HEAVY AND WET NATURE OF THIS SNOW WILL MAKE FOR TREACHEROUS
TRAVEL TONIGHT AND ALSO COULD BRING DOWN TREES MAKING POWER OUTAGES A
POSSIBILITY.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

SNOW WILL CONTINUE TO FALL SATURDAY AND SATURDAY NIGHT WITH AN
ADDITIONAL 1 TO 2 INCHES OF SNOW ACCUMULATION POSSIBLE.

SNOW WILL ALSO BE POSSIBLE SUNDAY THROUGH MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS TO THE NATIONAL
WEATHER SERVICE OFFICE IN JACKSON.

KYZ044-050>052-058>060-068-069-079-083-104-106-108-111-192115-
FLEMING-MONTGOMERY-BATH-ROWAN-ESTILL-POWELL-MENIFEE-ROCKCASTLE-
JACKSON-PULASKI-WAYNE-ELLIOTT-MORGAN-WOLFE-LEE-
INCLUDING THE CITIES OF...FLEMINGSBURG...MOUNT STERLING...
OWINGSVILLE...MOREHEAD...IRVINE...STANTON...FRENCHBURG...
MOUNT VERNON...MCKEE...SOMERSET...MONTICELLO...SANDY HOOK...
WEST LIBERTY...CAMPTON...BEATTYVILLE
108 PM EST FRI DEC 18 2009

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 PM THIS AFTERNOON TO
6 AM EST SUNDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN KENTUCKY.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

A DEVELOPING WINTER STORM WILL BRING SNOW TO EAST KENTUCKY BEGINNING
AS EARLY AS LATE THIS AFTERNOON. THE HEAVIEST SNOW WILL FALL THIS
EVENING AND OVERNIGHT. ACCUMULATIONS OF 1 TO 3 INCHES OF SNOW ARE
EXPECTED DURING THIS PERIOD.

TRAVEL WILL LIKELY BE IMPACTED ACROSS THE ADVISORY AREA THIS EVENING
AND OVERNIGHT WITH SNOW AND SLUSH COVERED ROADS POSSIBLE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

SNOW WILL CONTINUE TO FALL SATURDAY AND SATURDAY NIGHT WITH AN
ADDITIONAL INCH OF SNOW ACCUMULATION POSSIBLE.

SNOW WILL ALSO BE POSSIBLE SUNDAY THROUGH MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS TO THE NATIONAL
WEATHER SERVICE OFFICE IN JACKSON.

KYZ087-088-118-120-192115-
BELL-HARLAN-LETCHER-PIKE-
INCLUDING THE CITIES OF...MIDDLESBORO...PINEVILLE...HARLAN...
WHITESBURG...PIKEVILLE
108 PM EST FRI DEC 18 2009

...WINTER STORM WARNING IN EFFECT FROM 4 PM THIS AFTERNOON TO 6 AM
EST SUNDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN KENTUCKY.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

A DEVELOPING WINTER STORM WILL BRING SNOW TO EAST KENTUCKY. THE
HEAVIEST SNOW WILL FALL THIS EVENING AND OVERNIGHT. ACCUMULATIONS OF
4 TO 8 INCHES OF SNOW ARE EXPECTED DURING THIS PERIOD. UP TO A FOOT
OF SNOW WILL BE POSSIBLE ON THE HIGHEST PEAKS ALONG THE VIRGINIA
BORDER.

TRAVEL WILL LIKELY BECOME HAZARDOUS ACROSS THE OUTLOOK AREA THIS
EVENING AND OVERNIGHT WITH SNOW AND SLUSH COVERED ROADS POSSIBLE AS
EARLY AS LATE THIS AFTERNOON ON HIGHER ELEVATION ROADWAYS SUCH AS
U.S. 421...119 AND KENTUCKY HIGHWAY 160. THE HEAVY WET SNOW WILL ALSO
LIKELY BRING DOWN TREES MAKING POWER OUTAGES A POSSIBILITY.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

SNOW WILL CONTINUE TO FALL SATURDAY AND SATURDAY NIGHT WITH AN
ADDITIONAL 1 TO 2 INCHES OF SNOW ACCUMULATION POSSIBLE.

SNOW WILL ALSO BE POSSIBLE SUNDAY THROUGH MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS TO THE NATIONAL
WEATHER SERVICE OFFICE IN JACKSON.

SCHOETTMER