FXUS61 KILN 092348
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
648 PM EST WED DEC 9 2009

.SYNOPSIS...
MID AFTERNOON SURFACE ANALYSIS PLACES 975MB SURFACE LOW OVER
NORTHERN LOWER MICHIGAN. EFFECTS OF THIS SYSTEM ARE SIGNIFICANT
AND FAR REACHING FROM WESTERN GREAT LAKES/MIDWEST BLIZZARD...TO
STRONG DAMAGING WINDS IN THE OHIO VALLEY...TO TORNADO WARNINGS IN
PENNSYLVANIA. ARCTIC AIR IN THE WAKE OF THE SYSTEM SET TO MOVE IN
TONIGHT ON STRONG WEST WINDS...AS POLAR VORTEX /470DM 500MB
HEIGHTS/ HAS SAGGED INTO NORTHERN CANADA. TEMPERATURES IN THE
DAKOTAS TODAY REMAINING BELOW ZERO...WITH DANGEROUS WIND CHILLS.
MAIN STORY LOCALLY IS HIGH WINDS...WITH NUMEROUS 45 TO 55 MPH WIND
GUSTS...SOME SCATTERED TREE AND STRUCTURAL DAMAGE...AND SOME POWER
OUTAGES. HIGH WIND WARNING REMAINS IN EFFECT INTO THE EVENING HOURS.

&&

.NEAR TERM /THROUGH THURSDAY/...
ALL THE FOCUS IS ON TONIGHT...AND CURRENT STRONG WINDS. KILN WSR-
88D VWP...AS WELL AS RUC SOUNDINGS...CONTINUE TO SHOW SWLY WINDS
CRANKING INTO THE EARLY EVENING HOURS...ALBEIT WITH A SLOW TAPER
FROM ABOUT 5 PM ONWARD. WINDS FROM 3-8KFT OFF KILN RADAR HAVE BEEN
STEADY IN THE 50-55KT RANGE...AND STEEP LOW LEVEL LAPSE RATES ON
STRONG COLD ADVECTION WILL CONTINUE TO ALLOW THESE WINDS TO MIX TO
THE SURFACE. SAVING GRACE FROM A HIGHER END EVENT TODAY HAS BEEN
AMPLE LOW CLOUDS AND RATHER STRONG LIFT IN THE LOWEST 1-2KM AS
TROUGH AXIS SWINGS THROUGH. A GREAT DEAL OF SUNSHINE...AND A
STRONGER SUBSIDENCE SIGNAL WOULD HAVE SPELLED MORE WIDESPREAD
DAMAGING WINDS. HOWEVER...THUS FAR EVENT IS MARGINAL HIGH WIND
WARNING CRITERIA OR A VERY HIGH END ADVISORY...WITH POWER
OUTAGES/TREES/SIGN DAMAGE PRETTY SCATTERED ABOUT THUS FAR...AND
ONLY A HANDFUL OF ACTUAL MEASUREMENTS ABOVE WARNING CRITERIA. FEEL
IT MOST PRUDENT GIVEN THE BEST MIXING POTENTIAL NOW THROUGH 5
PM...AND WIND GUSTS SEEMINGLY INCREASING RIGHT NOW...TO JUST
CONTINUE THE HIGH WIND WARNING INTO THE EVENING HOURS INSTEAD OF
TRYING TO BE CUTE AND TIME A DOWNGRADE OUT OF WARNING POTENTIAL.
ACTUALLY FEEL THE TRANSITION FROM WARNING POTENTIAL TO SUB-
ADVISORY TYPE WINDS WILL BE QUICK THIS EVENING...AND IT MAY ALLOW
FOR JUST A COMPLETE CANCELLATION OF ALL WIND HEADLINES BY EARLY TO
MID EVENING. 

METEOROLOGY CERTAINLY SUPPORTS THIS AS MIXING DEPTH BEGINS TO
LOWER THIS EVENING...AND MAIN ISALLOBARIC COUPLET BEGINS TO PULL
NORTH/EAST OF THE LOCAL AREA. RUC FORECAST SOUNDINGS AND MEAN
LAYER 925-850MB WINDS SHOW A GOOD DECREASE BOTH IN SUSTAINED AND
GUST POTENTIAL THROUGH THE EARLY EVENING HOURS. SO WILL WORD TEXT
PRODUCTS IN THIS MANNER WHICH REALLY EMPHASIZES THE LATE
AFTERNOON/EARLY EVENING TIMEFRAME FOR MORE GUSTS TOWARD 55-60MPH
AND TREE/MINOR STRUCTURAL DAMAGE.

OTHER ISSUE IS THE SNOW/SNOW SHOWERS COVERING MUCH OF WRN
OH/INDIANA IMMEDIATELY AHEAD OF THE LOW LEVEL TROUGH AXIS. MUCH OF
THE STRONGER FORCING /QG/ AND STEEP LAPSE RATE-DRIVEN SNOW SHOWERS
WILL PULL NORTHEAST AND TAPER QUICKLY THIS EVENING...SO WILL RUN
WITH LOW PROBABILITIES OF MEASURING...AND COVERAGE WORDING. MOST
SHOULD SEE AT LEAST A PERIOD OF FLURRIES OR LIGHT SNOW...BUT
ACCUMULATIONS /IF ANY/ WILL BE MINOR. TEMPERATURES/WIND CHILLS
CONTINUE TO PLUMMET OVERNIGHT...MAKING FOR A RATHER COLD NIGHT.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
IN COMPARISON TO TODAY...THIS TIME PERIOD IS ACTUALLY QUITE
BENIGN AS STRONG MODEL AGREEMENT OF THE WRN CONUS SPLIT FLOW
CONTINUING...WITH MASSIVE OMEGA BLOCK STRUCTURE OVER
ALASKA/WESTERN CANADA WHICH ALLOWS FOR PHASING OF THE JET
UNDERCUTTING THE BLOCK...AND THE ARCTIC JET DIGGING DOWN INTO THE
LONGWAVE TROUGH OVER THE ERN CONUS. THIS GUARANTEES A STEADY
SUPPLY OF COLD AIR....AND DRY CONDITIONS THROUGH SATURDAY. AT THE
SURFACE...HIGH PRESSURE MOVES ACROSS THE ERN CONUS TOWARD THE
ATLANTIC SEABOARD BY SATURDAY EVENING. 

THURSDAY...THE COLDEST DAY AS 925MB TEMPS HOVER IN THE TEENS BELOW
ZERO /C/. STRONG WINDS TO CONTINUE OUT OF THE WEST EVEN QUITE A
WAYS FROM THE ANOMALOUSLY DEEP LOW PRESSURE. GOOD MIXING AGAIN
PROMISES WIND GUSTS TOWARD 30 MPH IN MOST AREAS...AND COMBINED
WITH TEMPERATURES IN THE TEENS/20S...WILL MAKE FOR WIND CHILLS IN
THE SINGLE DIGITS ABOVE ZERO...MAYBE EVEN BELOW. STILL QUITE A BIT
OF CLOUDS AS ONE LAST SHORTWAVE /SEEN IN WV IMAGERY OVER THE
INTERMOUNTAIN WEST NOW/ RUNS QUICKLY THROUGH THE BASE OF THE
LONGWAVE TROUGH WITH WEAK FORCING AND A VERY WEAK VERTICAL MOTION
RESPONSE. THUS WILL ONLY SERVE TO HOLD CLOUDS IN A LITTLE
LONGER...ESPECIALLY ACROSS CNTL OH...WITH MORE POTENTIAL FOR SOME
AFTERNOON SUNSHINE ACROSS NORTHERN KENTUCKY. CLEARS OUT THURS
NIGHT WITH TEMPS FALLING INTO THE TEENS AND POSSIBLY SINGLE
DIGITS...BUT WINDS WILL STAY UP SO RADIATIVE COMPONENT WILL BE DIMINISHED.

FRIDAY/SATURDAY...OUTSIDE OF SOME WAVES OF MID AND HIGH LEVEL
CLOUDS...THE MASSIVE SURFACE HIGH AND CANADIAN-ORIGIN AIRMASS WILL
CONTINUE THE DRY WEATHER WITH LOW DEWPOINTS. RETURN FLOW /SWLY/
AROUND THE BACK SIDE OF THE HIGH ON FRIDAY NIGHT/SATURDAY WILL
BRING SOME MODERATION IN THE TEMPERATURES...BUT STILL BELOW NORMAL.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
HIGH PRESSURE SETTLED OVER THE MID ATLANTIC WILL HAVE A RIDGE AXIS 
EXTENDING NORTHWEST THROUGH THE OHIO VALLEY TO START THE FORECAST ON 
SATURDAY. THE AXIS WILL MOVE NORTH AS FLOW KICKS AROUND TO THE SOUTH 
AND MODELS ARE TRYING TO DEVELOP A LOW PRESSURE SYSTEM PROGRESSING 
FROM THE GULF TO THE SOUTHEAST COAST ON SUNDAY. THE OHIO VALLEY MAY 
SEE A CHANCE FOR THE NORTHERN EDGE OF THIS SYSTEM TO BRING A SHOT OF 
RAIN BEGINNING LATE SATURDAY NIGHT. HOWEVER...THIS IS IN THE WARM 
SECTOR WITH LITTLE FORCING NOTED IN THE REGION. I HAVE SHAVED BACK 
GUIDANCE NUMBERS FOR POPS EARLY IN THE EXTENDED FORECAST WITH THIS 
SYSTEM. SUNDAY IS A PERIOD BETWEEN SYSTEMS WHERE TEMPERATURES 
MODERATE AND THE ATMOSPHERE DRIES OUT. FORECAST HIGHS ON SUNDAY AND 
MONDAY MAY BE A LITTLE HIGH WITH THE EXPECTED CLOUD COVER...EVEN 
WITH SOUTHERLY FLOW.

AFTER THE WEEKEND...A COLD FRONT CROSSES THE OHIO VALLEY MONDAY 
NIGHT AND INCREASES THE CHANCE FOR PRECIPITATION. THIS WILL PULL 
COLD AND DRY AIR INTO THE OHIO VALLEY ON STRONG NORTHERLY FLOW 
BEHIND IT...CUTTING OFF ANY CHANCES FOR PRECIPITATION FOR MID WEEK. 
MODEL GUIDANCE FOR THIS PERIOD IS IN A BIT OF FLUX. I TRENDED 
TOWARDS HPC GUIDANCE BUT LOWERED THE CHANCE FOR PRECIP WHILE KEEPING 
THE TEMPERATURES ON THE COOL SIDE...A BIT CLOSER TO THE PREVIOUS 
FORECAST.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
ALTHOUGH WIND GUSTS WILL NOT BE AS HIGH AS SEEN EARLIER
TODAY...WIND GUSTS TO SOME DEGREE WILL CONTINUE THROUGH THE TAF
PERIOD. WIND GUSTS WILL DECREASE OVERNIGHT TO AROUND 22 KTS
HOWEVER DURING THE DAY ON THURSDAY EXPECT WIND GUSTS TO INCREASE
TO AROUND 28 KTS IN SOME LOCATIONS. SNOW SHOWERS OR FLURRIES THAT
IMPACT TAF SITES DURING THE OVERNIGHT HOURS WILL BE LIGHT. KEPT
PRECIPITATION AROUND LONGER ACROSS THE NORTHERN TAF SITES. LOOKING
AT CURRENT OBS...VISBYS IN SNOW SHOWERS ARE MAINLY VFR WITH ONLY A
FEW POCKETS OF MVFR...THEREFORE KEPT VISBYS VFR. MVFR CIGS WILL
ALSO BE PRESENT DURING THE OVERNIGHT HOURS BEFORE LOW PRESSURE
SYSTEM MOVES OFF TO THE NE. EXPECT A LONGER DURATION OF THESE MVFR
CIGS ACROSS THE NORTH. SOUTHERN TAF SITES SUCH AS KLUK AND KCVG
WILL ONLY INTERMITTENTLY SEE MVFR CIGS AS THEY ARE ON THE BORDER
BETWEEN VFR AND MVFR CIGS. CONDITIONS WILL SLOWLY BEGIN TO IMPROVE
ON THURSDAY WITH CIGS IMPROVING TO VFR AT TAF SITES AND CLOUDS
BEGINNING TO SCATTER OUT.

OUTLOOK...MVFR CEILINGS POSSIBLE ON SUNDAY.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HIGH WIND WARNING UNTIL 1 AM EST THURSDAY FOR OHZ026-034-035-
     042>046-051>056-060>065-070>074-077>082-088.
KY...HIGH WIND WARNING UNTIL 1 AM EST THURSDAY FOR KYZ089>100.
IN...HIGH WIND WARNING UNTIL 1 AM EST THURSDAY FOR INZ050-058-059-
     066-073>075-080.

&&

$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU/HICKMAN
LONG TERM...FRANKS
AVIATION...NOVAK