FXUS61 KILN 081426
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
926 AM EST TUE DEC 8 2009
.SYNOPSIS...
A DEEPENING LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS WILL
MOVE TO THE WESTERN GREAT LAKES BY WEDNESDAY MORNING. THE LOW
WILL CONTINUE TO DEEPEN AS IT MOVES OFF TO THE NORTHEAST ON
WEDNESDAY...SENDING A STRONG COLD FRONT EAST ACROSS THE AREA.
COLD HIGH PRESSURE WILL GRADUALLY BUILD INTO THE OHIO VALLEY
THURSDAY INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE IS OVERSPREADING OHIO VALLEY THIS MORNING...COMING IN
AROUND 10KFT AND SLOWLY SATURATING THE COLUMN FROM THE TOP DOWN.
IT WILL TAKE A WHILE TO OVERCOME THE DRY LEVEL AROUND 3KFT AND I
LIKED THE LATER TIMING NOTED ON THE 12Z NAM...COMBINED WITH LAST
NIGHTS ECMWF RUN. THIS HELPED SLOW THE ONSET OF RAIN/SLEET/SNOW IN
THE NORTHERN CWA AND ESPECIALLY IN THE NORTHEAST...BUT DID NOT
APPRECIABLY CHANGE THE CHANCE OF PRECIP FOR THE ENTIRE TODAY
PERIOD...MERELY OFFSET IT.
LEADING EDGE OF THE RAIN COMING IN LATER THIS AFTERNOON WILL
PROBABLY CONTIAIN A WINTERY MIX AS THE COLUMN MOISTENS UP RIGHT
ALONG THE ZERO DEGREE ISOTHERM FOR SEVERAL THOUSAND FEET. ANY MIX
SHOULD BE SHORT-LIVED AND NOT POSE MUCH OF AN INITIAL THREAT TO
THE REGION AS TEMPS WARM UP AND PTYPE COMES OVER TO ALL RAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
HAVE TAKEN A BLEND OF THE GFS/ECMWF FOR THE SHORT TERM FORECAST.
DEEPENING LOW PRESSURE WILL BE NEAR SRN LAKE MICHIGAN WEDNESDAY
MORNING. THE LOW IS FORECAST TO TRACK NE TO A POSITION NEAR SRN
QUEBEC BY THURSDAY MORNING. AS THE LOW MOVES NORTHEAST...A STRONG
COLD FRONT WILL SWEEP FROM WEST TO EAST ACRS THE FCST AREA
WEDNESDAY MORNING. A TIGHTENING SFC PRESSURE GRADIENT...STRONG
CAA...AND WINDS BETWEEN 50 AND 60 KNOTS BETWEEN 925 MB AND 850 MB
WILL BRING THE THREAT FOR HIGH WINDS. WIND GUSTS OF 42 TO 48 KNOTS
LOOK LIKE A SURE BET ON WEDNESDAY. WHETHER LOCATIONS CAN GUST TO
50 KNOTS OR SLIGHTLY HIGHER IS STILL SOMEWHAT IN QUESTION GIVEN
EXPECTED LOW LEVEL MOIST...CLOUDY ENVIRONMENT. HOWEVER...WITH MID
LVL DPVA MOVING INTO THE REGION WHICH WILL GENERATE RAIN AND SNOW
SHOWERS...THE INSTABILITY FACTOR ASSOCIATED WITH THE SHOWERY PCPN
MAY ACT AS A CONDUIT FOR HIGHER WIND GUSTS IN THE FORM OF
DOWNDRAFTS. AS A RESULT... WILL CONTINUE WITH THE HIGH WIND WATCH
WHICH IS IN EFFECT FROM WEDNESDAY MORNING INTO WEDNESDAY NIGHT.
THIS WILL ALLOW THE DAY SHIFT ONE LAST LOOK AT THE LATEST MODEL
DATA TO DECIDE ON A HIGH WIND WARNING...WIND ADVISORY OR A
COMBINATION OF BOTH. EVEN SO...WIND GUSTS IN THE 42 TO 48 KNOT
RANGE WILL CAUSE TREE LIMBS TO COME DOWN...POSSIBLY RESULTING IN
SOME POWER OUTAGES. TEMPERATURES ON WEDNESDAY WILL TUMBLE THROUGH
THE DAY AS COLD ARCTIC AIR PUSHES SE INTO THE REGION. SNOW SHOWERS
WILL GRADUALLY TAPER OFF FROM SW TO NE WEDNESDAY NIGHT AS
AFOREMENTIONED LOW PRESSURE CONTINUES TO PULL AWAY.
ON THURSDAY...FORECAST AREA WILL BE BETWEEN DEPARTING LOW PRESSURE
TO THE NORTHEAST AND COLD HIGH PRESSURE BUILDING IN FROM THE
SOUTHWEST. BRISK WINDS WILL CONTINUE WITH WIND GUSTS IN THE 30 TO
35 MPH RANGE. SKIES WILL BECOME PARTLY SUNNY. TEMPERATURES WILL
STRUGGLE TO WARM FROM MORNING LOWS IN THE MID TEENS TO LOWER 20S.
WILL CONTINUE TO UNDERCUT MOS GUIDANCE WITH HIGHS RANGING FROM
NEAR 20 NW TO THE UPPER 20S FAR SOUTHEAST.
SFC HIGH PRESSURE WILL GRADUALLY BUILD INTO THE OHIO VALLEY
THURSDAY NIGHT INTO FRIDAY...BRINGING DRY BUT CONTINUED COLD
WEATHER. WINDS WILL DIMINISH.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH THE REST OF THE
LONG TERM PERIOD AS A BROAD UPPER LEVEL TROUGH REMAINS OVER THE
NORTHEASTERN UNITED STATES THROUGH EARLY NEXT WEEK. MODELS ARE
CONTINUING TO HINT AT SOME OVERRUNNING PCPN SPREADING UP INTO OUR
AREA THIS WEEKEND. TIMING AND PLACEMENT IN THESE TYPES OF
SITUATIONS ARE USUALLY DIFFICULT. HOWEVER...BOTH THE GFS AND ECMWF
ARE IN PRETTY GOOD AGREEMENT BRINGING SOME LIGHT PCPN UP FROM THE
SOUTH SATURDAY INTO SUNDAY. WILL THEREFORE GO AHEAD AND ALLOW FOR
SOME 20-30 POPS DURING THAT PERIOD. AT THIS POINT...IT LOOKS LIKE
TEMPS SHOULD BE COLD ENOUGH FOR THE BULK OF ANY PCPN TO REMAIN IN
THE FORM OF SNOW.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
MVFR/VFR CIGS STILL LOCKED IN MUCH OF THE AREA THIS MORNING...AS
HI-RES/SHORT TERM MODELS /NAM AND RUC/ STRUGGLE WITH THIS MOISTURE
AROUND 3KFT. THE TREND IN THESE DATASETS YET THIS MORNING IS TO
ERODE THE REMAINING STRATUS...BUT THIS HAS BEEN VERY SLOW IN
HAPPENING. RECENT TRENDS AT CVG TO SCATTER OUT...AND SOME KENTUCKY
SITES...AS WELL AS NORTH OF I-70 MAKE ME BELIEVE THE PROCESS WILL
CONTINUE...BUT WINDOW BECOMES MORE NARROW WITH TIME AS LARGE SCALE
WARM/MOIST ADVECTION WILL CONTINUE TO INCREASE INTO THE AFTERNOON
DOWNSTREAM OF MAJOR CENTRAL CONUS STORM SYSTEM. SO SHORT TERM
TRENDS IN ALL TAFS IS TO CONTINUE TO TRY AND SHOW CIGS TO
ERODE...AND MINOR IMPROVEMENTS TO MARGINAL MVFR VIS.
STRONG MOISTURE TRANSPORT/LIFT INTO THE AREA THIS AFTERNOON FROM
SOUTHWEST TO NORTHEAST SHOULD YIELD A HEALTHY RAIN SHIELD
ADVANCING NORTH INTO THE AREA...FIRST AT CVG THEN INTO DAY/ILN AND
EVENTUALLY CMH/LCK BY MID TO LATE AFTERNOON. LATEST RUC/NAM-WRF
TRENDS ARE FOR MARGINALLY WARMER TEMPERATURES IN THE BOUNDARY
LAYER AND ALOFT...THUS PULLED MENTION OF BRIEF MIX OUT OF ILN.
KEPT IT IN HOWEVER FOR CMH/DAY/LCK WHERE CRITICAL WET BULB/WARM
NOSE TEMPERATURES RIGHT ON THE THRESHOLD TO SUPPORT A BURST OF
WINTERY MIX BEFORE LOWER TROPOSPHERIC WARMING OVERWHELMS THE AREA
ON STRONG SOUTHEAST WINDS...CHANGING ALL PCPN TO RAIN. THE RAIN
COULD BE QUITE STEADY/HEAVY FOR THE SRN TAF SITES...AND MAY EVEN
INCLUDE A RUMBLE OF THUNDER BUT KEPT THIS OUT OF TAFS FOR NOW.
MUCH OF LATE AFTERNOON/NIGHT SHOULD SEE WIDESPREAD IFR
CIGS/VSBYS...ESPECIALLY THE SRN SITES.
LASTLY...ANOMALOUSLY DEEP LOW PRESSURE NEAR CHICAGO TO SEND STRONG
COLD FRONT SURGING THROUGH THE TAF SITES LATE TONIGHT/WED MORNING
WITH WIND SHIFT FROM SOUTHEAST TO SOUTHWEST...AND BIG BUMP IN
WINDSPEED. INCLUDED THIS TREND IN CVG /30HR/ TAF WITH THE OTHER
TAFS TO FOLLOW SUIT ON NEXT ISSUANCE. WIND GUSTS IN EXCES OF 50
MPH POSSIBLE ON WEDNESDAY WITH PLENTY OF STRATOCUMULUS AND
RAIN/SNOW SHOWERS.
OUTLOOK...WIDESPREAD MVFR/IFR CIGS AND STRONG WINDS ARE LIKELY
WEDNESDAY NIGHT. MORE IFR/MVFR CIGS AND PRECIPITATION POSSIBLE
SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HIGH WIND WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY
NIGHT FOR OHZ026-034-035-042>046-051>056-060>065-070>074-
077>082-088.
KY...HIGH WIND WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY
NIGHT FOR KYZ089>100.
IN...HIGH WIND WATCH FROM WEDNESDAY MORNING THROUGH LATE WEDNESDAY
NIGHT FOR INZ050-058-059-066-073>075-080.
&&
$$
SYNOPSIS...HAWBLITZEL
NEAR TERM...FRANKS
SHORT TERM...HICKMAN/JGL
LONG TERM...JGL
AVIATION...BINAU
