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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 250255
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
955 PM EST SAT JAN 24 2015

.SYNOPSIS...
A CLIPPER SYSTEM WILL TRACK ACROSS THE REGION SUNDAY INTO SUNDAY
NIGHT...BRINGING ACCUMULATING SNOW ALONG AND NORTH OF INTERSTATE 70.
COLDER WEATHER WILL MOVE IN BEHIND THIS SYSTEM FOR THE BEGINNING
OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPDATE FOCUSED MAINLY IN THE CLOUD COVER THIS EVENING, AREAS IN
THE S AND W HAVE BROKEN OUT OF THE LOW CLOUDS FOR A FEW
HOURS...BUT LATEST SATELLITE LOOP SHOWS MID CLOUDS WORKING E
TOWARDS THE AREA...SO SKY SHOULD GO MOSTLY CLOUDY BY MIDNIGHT OR
SHORTLY AFTERWARDS. HAVE CLOUDY SKIES FOR THE NORTH AND
INCREASING CLOUDS IN THE SOUTH.

00Z NAM HAS TRICKLED IN ALONG WITH SOME RAP AND HRRR AND THEY HAVE
TRENDED A LITTLE SLOWER WITH THE ONSET OF THE PCPN TOMORROW. SO
BACKED OFF ON THE PCPN AT THE END OF THE TONIGHT PERIOD.

PREVIOUS LOWS IN THE LOWER 30S STILL LOOK GOOD.


&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
TRICKY SNOW FORECAST WITH SOME DIGGING OF THE CLIPPER SYSTEM AS IT
ENTERS THE REGION ON SUNDAY...WITH THE ONLY LOCATION TO REMAIN
PREDOMINATELY SNOW BEING THE FAR NW. THE S/WV STILL SHOWING SIGNS
OF AMPLIFICATION AS IT DIGS SOUTH INTO FCST AREA. PRECIP IN MOST
LOCATIONS WILL BEGIN AS RAIN ON SUNDAY MORNING.

HAVE SLOWED ONSET SLIGHTLY...AND DUE TO THE WARM AIR ADVECTION
AND LINGERING PERIOD OF RAIN OR RAIN/SNOW IN ESPECIALLY CENTRAL
OHIO...BEGAN SNOW ADVISORY AT 15Z/10AM. MOST LOCATIONS IN ADVISORY
WILL SEE 3-5 INCHES WITH SOME 6 INCH AMOUNTS...BUT THE TRICK IS IN
THE SURFACE/LOW LEVEL TEMPERATURES.

MODELS ARE SLOWLY PICKING UP ON THE STRENGTH OF THE SYSTEM...AS
WELL AS GFS/ECMWF CONVERGING ON TRACK...WITH NAM WARMER AND SLOWER
WITH A MORE NORTHERLY TRACK. LOOKING AT MODEL SOUNDINGS FOR
KDAY/KILN...CHANGEOVER TO ALL SNOW LIKELY NOT TO OCCUR UNTIL AFTER
7PM SUNDAY...WHICH IS BEHIND THE HEAVIEST PRECIPITATION POTENTIAL.
GREATEST UNCERTAINTY WILL BE IN THE AREA JUST SOUTH OF THE
ADVISORY...WHERE LOW LEVEL THERMAL PROFILES ARE VERY CLOSE TO
FREEZING. EARLIER COLD AIR INTRUSION WILL RESULT IN MORE SNOW
HERE...ALONG WITH HIGHER SNOW TO LIQUID RATIOS. HAVE GENERALLY
GONE WITH SNOW AT ONSET TO BE A 10:1 RATIO...THEN AS THE COLD AIR
DIGS INTO ESPECIALLY THE UPPER GREAT MIAMI VALLEY AND ST. MARYS
BASIN...RATIOS MORE IN THE 14:1 WITH THE COLDER AIR.

HAVE CONTINUED HOURLY TEMPERATURE TACTIC OF A BLEND OF MODEL 2M
TEMPERATURES DURING THE EVENT...AND THEN BELOW MODEL GUIDANCE FOR
SUNDAY NIGHT.

MONDAY HAS THE SYSTEM RETREATING WITH JUST LINGERING SNOW SHOWERS
IN THE EASTERN FCST AREA YIELDING LESS THAN AN INCH OF SNOW TOTAL.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A WEAK S/WV WILL DROP SOUTHEAST INTO THE REGION MONDAY NIGHT INTO
TUESDAY. MODELS DIFFER WITH ITS PLACEMENT. THE ECMWF IS FARTHER WEST
WHILE THE NAM/GFS ARE FARTHER EAST. HAVE GONE WITH THE LATTER WHICH
KEEPS CONTINUITY. THIS CALLS FOR A CHANCE OF LIGHT SNOW.

HIGH PRESSURE WILL BRIEFLY BUILD INTO THE AREA TUESDAY NIGHT INTO
WEDNESDAY. COLD TEMPERATURES ON TUESDAY WILL MODIFY SOME BY
WEDNESDAY.

FOR THE PERIOD WEDNESDAY NIGHT INTO THURSDAY NIGHT...MODELS ARE IN
FAIRLY DECENT AGREEMENT WITH THE TIMING OF UPCOMING WEATHER SYSTEMS.
A LEAD S/WV FOLLOWED BY A STRONG S/WV WILL MOVE THROUGH THE REGION
DURING THIS TIME FRAME. THIS WILL BE REFLECTED AT THE SURFACE BY LOW
PRESSURE AND A COLD FRONT. PCPN SHOULD ENCROACH THE WEST LATE
WEDNESDAY NIGHT AND SPREAD EAST ON THURSDAY. HOW FAST TEMPERATURES
WARM AHEAD OF THE FRONT BY PCPN ONSET WILL DETERMINE PCPN TYPE.
ALTHOUGH IT IS LOOKING LIKE A GOOD PART OF THE AREA WILL SEE SOME
SLEET/FREEZING RAIN AT THE ONSET...HAVE GONE WITH RAIN/SNOW MIX ATTM
GIVEN HOW FAR OUT IN THE EXTENDED THIS SYSTEM IS (GIVEN THAT IT IS
DIFFICULT TO PINPOINT MIXED PCPN TYPE THIS FAR OUT). THE ENTIRE
REGION WILL LIKELY GO OVER TO ALL RAIN FOR A TIME THURSDAY AFTN
AHEAD OF THE FRONT. IN THE WAKE OF THE SYSTEM THURSDAY NIGHT...WE
SHOULD SEE PCPN MIX WITH THEN CHANGE OVER TO A BRIEF PERIOD OF SNOW
BEFORE ENDING.

FOR FRIDAY INTO FRIDAY NIGHT...HIGH PRESSURE WILL ONCE AGAIN BUILD
INTO THE REGION. TEMPERATURES WILL COOL BACK DOWN TO BELOW SEASONAL
NORMALS.

LONG RANGE MODELS DISAGREE ON HOW FAST A MAJOR WEATHER PATTERN
CHANGE WILL OCCUR OVER THE WEEKEND INTO NEXT WEEK AS MUCH COLDER
ARCTIC AIR PLUNGES SOUTHEAST INTO THE GREAT LAKES AND THE OHIO
VALLEY. HAVE SIDED WITH THE ECMWF ATTM WHICH IS FASTER AND PUSHES AN
ARCTIC FRONT INTO THE REGION DURING THE SATURDAY/SUNDAY TIME FRAME.
WILL FORECAST A CHANCE OF SNOW WITH THIS SYSTEM.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
SERIES OF MVFR DECK CONTINUE TO DROP SE ACROSS THE REGION.
CVG/LUK/ILN HAVE CURRENTLY SCATTERED OUT...BUT CLOUDS IN CENTRAL
INDIANA AREA HEADING BACK IN. IT WILL BE CLOSE IF CVG/LUK SEE MVFR
CIGS LATER THIS EVENING. SATELLITE LOOP LOOKS LIKE THEY WILL WORK
IN FOR A COUPLE OF HOURS BEFORE SCATTERING BACK OUT. FOR THE NRN
TAFS MVFR CIGS SHOULD LINGER ALL NIGHT LONG.

AFT 12Z SUNDAY...THE SRN TAFS WILL SEE LOWERING CIGS AHEAD OF
APPROACHING STORM SYSTEM...REACHING MVFR CONDITIONS BETWEEN
16-18Z. NRN TAFS WHICH WILL HAVE LINGERING MVFR CIGS WILL SEE THEM
FALL TOWARD IFR AS PCPN WORKS IN AROUND 15Z. ANY PCPN SHOULD FALL
AS RAIN AT ALL THE TAFS THRU 21Z.

RAIN WILL CHANGE TO SNOW AT DAY/CMH-LCK AROUND 21Z...DROPPING CIGS
AND VSBYS. THE SRN TAFS PROBABLY WONT SEE THE CHANGE OVER TO SNOW
UNTIL AFT 00Z.

OUTLOOK...MVFR/IFR CIGS AND VSBYS LIKELY SUNDAY NIGHT. MVFR
CIGS WILL LIKELY PERSIST INTO MONDAY. MVFR CIGS AND VSBYS POSSIBLE
AGAIN TUESDAY THEN THURSDAY.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY FROM 10 AM SUNDAY TO 7 AM EST MONDAY
     FOR OHZ026-034-035-042>046-051>056.
KY...NONE.
IN...WINTER WEATHER ADVISORY FROM 10 AM SUNDAY TO 7 AM EST MONDAY
     FOR INZ050.

&&

$$
SYNOPSIS...JDR
NEAR TERM...SITES
SHORT TERM...JDR
LONG TERM...HICKMAN
AVIATION...SITES