Area Forecast Discussion
Issued by NWS Wilmington, OH

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000
FXUS61 KILN 200224
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
924 PM EST WED NOV 19 2014

.SYNOPSIS...
A COLD FRONT WILL PUSH EAST ACROSS THE AREA TONIGHT...BRINGING A
FEW SNOW SHOWERS AND A REINFORCING SHOT OF COLD AIR. HIGHS
THURSDAY AND FRIDAY WILL BE WELL BELOW NORMAL. INCREASING
SOUTHERLY WINDS WILL ALLOW FOR A WARMING TREND THROUGH THE
WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A MID LEVEL SHORT WAVE ROTATING THROUGH THE SOUTHERN GREAT LAKES
WILL HELP PUSH A COLD FRONT EAST ACROSS THE AREA TONIGHT. AN AXIS
OF BETTER LOW LEVEL CONVERGENCE WILL WORK EAST WITH THE FRONT THIS
EVENING INTO THE OVERNIGHT HOURS. MOISTURE IS FAIRLY SHALLOW BUT
THERE MAY BE ENOUGH FORCING TO PRODUCE SOME ISOLATED TO POSSIBLY
SCATTERED SNOW SHOWERS. WE COULD THEN SEE A FEW FLURRIES LINGER
THROUGH MUCH OF THE REST OF THE NIGHT AS WE GET INTO SOME DECENT
CAA AND CYCLONIC FLOW BEHIND THE FRONT. SOUTHWEST FLOW AHEAD OF
THE FRONT WILL LEAD TO SOME NON DIURNAL TEMPERATURES INTO THIS
EVENING...ESPECIALLY ACROSS THE EAST. OVERNIGHT LOWS WILL RANGE
FROM THE TEENS IN THE NORTHWEST TO THE LOWER 20S IN THE SOUTHEAST.
WEST WINDS CONTINUE TO GUST WELL OVER 20 KNOTS SO INCREASED SPEEDS
THROUGH TONIGHT.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
CYCLONIC LOW LEVEL FLOW AND CONTINUED WEAK CAA SHOULD ALLOW FOR
SOME LINGERING STRATOCUMULUS INTO THE DAY ON THURSDAY. TOUGH TO RULE
OUT A FEW FLURRIES TOO...ESPECIALLY ACROSS OUR NORTHEAST.
OTHERWISE...SURFACE HIGH PRESSURE WILL BUILD EAST ACROSS THE
REGION THURSDAY AFTERNOON INTO FRIDAY. THIS WILL ALLOW FOR
DECREASING CLOUDS BY THURSDAY NIGHT AND MOSTLY SUNNY SKIES ON
FRIDAY.

THE SURFACE HIGH SHOULD BE CENTERED OVER US BY 12Z FRIDAY MORNING.
ASSUMING WE CLEAR OUT THURSDAY NIGHT...EXPECT GOOD RADIATIONAL
COOLING...ESPECIALLY IN AREAS WITH LINGERING SNOW COVER. WILL GO
AHEAD AND UNDERCUT GUIDANCE A FEW DEGREES...RANGING LOWS FROM THE
SINGLE DIGITS NORTHWEST TO THE MID TEENS SOUTHEAST. HIGHS ON
THURSDAY WILL BE WELL BELOW NORMAL...RANGING FROM THE LOW/MID 20S
NORTH TO NEAR 30 SOUTH. A FAIR AMOUNT OF SUN ON FRIDAY WILL ALLOW
FOR SLIGHTLY WARMER TEMPERATURES BUT READINGS WILL STILL BE WELL
BELOW NORMAL.

INCREASING SOUTHWESTERLY FLOW WILL LEAD TO DEVELOPING
WAA/ISENTROPIC LIFT FRIDAY NIGHT. THIS WILL RESULT IN INCREASING
CLOUDS AND PERHAPS A FEW SHOWERS MOVING IN FROM THE SOUTHWEST
LATE. ASSUMING THE CLOUDS HOLD OFF LONG ENOUGH...TEMPERATURES WILL
LIKELY FALL OFF EARLY FRIDAY EVENING AND THEN SLOWLY RISE THROUGH
THE OVERNIGHT HOURS. HOWEVER...SURFACE TEMPS WILL STILL BE BELOW FREEZING
SO ANY PCPN WOULD LIKELY FALL AS AT LEAST A MIX OF FREEZING RAIN
GIVEN THE WARMER AIR MOVING IN ALOFT.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
FOCUS IN THIS PERIOD WILL BE THE VERY DEEP LOW PRESSURE SYSTEM TO
DEVELOP VIA PHASING MID/UPPER LEVEL SHORTWAVE TROUGHS LATE IN THE
WEEKEND IN THE MISSISSIPPI VALLEY AND WESTERN GREAT LAKES.
CHANGEABLE TEMPERATURES...GUSTY WINDS...AND HIGH PROBABILITY OF
SHOWERS IS EXPECTED AROUND THIS SYSTEM.

AT 12Z SATURDAY MORNING....STRONG ARCTIC HIGH PRESSURE /1032 MB/
WILL HAVE PUSHED SOUTHEAST INTO THE CAROLINAS WITH RETURN FLOW/WARM
ADVECTION REGIME WELL ESTABLISHED OVER THE OHIO VALLEY ALOFT.
DECOUPLED BOUNDARY LAYER/WEAK SURFACE FLOW MEANS THAT SURFACE TEMPS
LIKELY BE NEAR OR BELOW FREEZING AS WARM/MOIST ADVECTION IS RAMPING
UP. ALOFT...A POTENT SOUTHERN STREAM SHORTWAVE TROUGH WILL BE ACROSS
WRN TEXAS AND A SLIGHTLY WEAKER SHORTWAVE IN BRITISH COLUMBIA IN THE
NRN STREAM.

ON SATURDAY MORNING...THE WARM/MOIST ADVECTION ALOFT /ISENTROPIC
ASCENT/ WILL LEAD TO GRADUAL MOISTENING ESPECIALLY ALONG/WEST OF
I-71 WHERE FCST SOUNDINGS /19.12Z NAM...GFS...GFSP...ECMWF/ ALL
SUGGEST ENOUGH LOW/MID LEVEL MOISTURE FOR LIGHT/SCATTERED PRECIP
DVLPMENT. ELEVATED WARM LAYER > 5C SUGGESTS COMPLETE HYDROMETEOR
MELTING THUS ANYTHING REACHING THE GROUND /VERY LIGHT/ WOULD BE
FREEZING RAIN OR RAIN...THERE IS SOME UNCERTAINTY ON HOW QUICKLY THE
BOUNDARY LAYER WILL WARM FRIDAY NIGHT/SATURDAY MORNING. RIGHT NOW AM
NOT SEEING ENOUGH DEPTH/BREADTH OF THE VERTICAL MOTION TO SUGGEST A
WIDESPREAD TRAVEL ISSUE...BUT SOMETHING THAT WILL NEED TO BE WATCHED
IN THE EARLY MORNING HOURS BEFORE THE WARM ADVECTION DEEPENS AND ALL
RISE ABOVE FREEZING LATER SAT MORNING.

ON SATURDAY NIGHT/SUNDAY...DEEPENING SHORTWAVE IN THE NRN STREAM AS
IT CROSSES ALBERTA/SASK BEGINS TO STEER DEEPENING SRN STREAM WAVE IN
THE ARKLATEX MORE NNEWD WITH RAPID PHASING OF THE STREAMS TO OCCUR
BY SUNDAY NIGHT. BY MONDAY MORNING...ANOMALOUS/DEEP CLOSED LOW WILL
BE OVER MN AS A RESULT OF THIS PROCESS. AT THE SURFACE...AMALGAM OF
DETERMINISTIC RUNS /GFS...GFSP...ECMWF...CMC...AS WELL SOME
EXPERIMENTAL DATA/ ALL INDICATE A DRAMATIC PRESSURE FALL AND
DEEPENING OF THE SFC LOW ATTENDANT TO THE SRN STREAM
SHORTWAVE...WITH A SUB 980MB CYCLONE NEAR CHICAGO/MADISON BY LATER
SUNDAY NIGHT. THIS OPENS UP THE GULF BY SUNDAY AS STRONG SHORTWAVE
DYNAMICS CROSS THE AREA. CONTINUED HIGH RAIN CHANCES AND MAY NEED TO
CONSIDER ADDING THUNDER IN THE SOUTH ABOVE THE RELATIVELY STABLE
NEAR-SURFACE LAYER GIVEN DYNAMICS/NON-ZERO ELEVATED INSTBY.

OCCLUSION TO RAPIDLY TAKE PLACE INTO MONDAY WITH COLD FRONT CROSSING
THE AREA MONDAY MORNING. CONTINUED HIGHER RAIN CHANCES WITH
DIMINISHING TREND THEREAFTER...THEN DRY MIDWEEK.

TEMPS WILL BE A SOURCE OF POTENTIAL SIGNIFICANT ERROR IN THE FCST
GIVEN SEVERAL INSTANCES OF NON-DIURNAL/ADVECTION DRIVEN TEMP
RISES/FALLS. KEPT TEMPS COOL SATURDAY WITH MAINLY A SSELY FLOW AND
WEAKER VERTICAL MIXING...THIS IS NOT A GOOD WARMING WIND DIRECTION
FOR OUR AREA ESP WITH PLENTY OF CLOUDS. ALLOWED FOR CONTINUED RISE
IN TEMPS SAT NIGHT THROUGH SUNDAY....TIGHTENED THE DIURNAL RANGE
QUITE A BIT THESE DAYS. ALLOWED FOR STEADY/FALLING TEMPS ON MONDAY
IN WAKE OF COLD FRONTAL PASSAGE.  BY TUES/WED...TEMPS BACK WELL
BELOW NORMAL /30S AND LOWER 40S/ AMIDST STRONG COLD ADVECTION.

ALSO INCREASED WINDS OVER BLENDED GUIDANCE GIVEN SUB 980MB CYCLONE
TO OUR WEST. MAY NEED TO GO HIGHER STILL ESPECIALLY SUNDAY/SUNDAY
NIGHT/MON MORNING.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
CONDITIONS ARE VFR TO START. THAT IS EXPECTED TO CHANGE WITHIN THE
NEXT FEW HOURS AS A COLD FRONT WORKS IN FROM THE WEST...BRINGING
MVFR CEILINGS. A FEW SNOW SHOWERS MAY DEVELOP IN THE VICINITY OF
TAF SITES BUT WIDESPREAD PRECIP IS NOT ANTICIPATED. CEILINGS MAY
LIFT TO VFR AROUND 14Z...THOUGH MODEL DIFFERENCES LEND UNCERTAINTY
TO THIS PREDICTION. WINDS WILL BE OUT OF THE WEST TO
SOUTHWEST...WITH GUSTS OVER 20 KNOTS AT TIMES IN A RATHER TIGHT
PRESSURE GRADIENT.

OUTLOOK...MVFR CIGS POSSIBLE SUNDAY AND MONDAY.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.

&&

$$
SYNOPSIS...JGL
NEAR TERM...CONIGLIO/JGL
SHORT TERM...JGL
LONG TERM...BINAU
AVIATION...CONIGLIO






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