FXUS61 KILN 240542
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
1242 AM EST THU DEC 24 2009
.SYNOPSIS...
UPPER LEVEL RIDGING WILL CONTINUE TO BUILD INTO THE OHIO VALLEY
TONIGHT AND MOVE EAST OF THE AREA TOMORROW. A STRONG UPPER LOW
WILL DIG INTO THE CENTRAL U.S. TOMORROW AND FRIDAY...BRINGING
WIDESPREAD RAIN INTO THE OHIO VALLEY BY TOMORROW NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AFTER CONVINCING MYSELF TO PULL SMALL CHANCES OF PRECIPITATION
OVERNIGHT IN WESTERN CWA...NEW 24.00Z RUC HAS BROUGHT BACK ENOUGH
UNCERTAINTY TO KEEP THE FORECAST AS-IS. DRYING NORTHEAST FLOW IN
THE BOUNDARY LAYER CURRENTLY WITH DEWPTS TUMBLING INTO THE
TEENS/LOWER 20S OVER CENTRAL OH AND EXPECT THIS TO CONTINUE AS IT
SPREADS SOUTH/WEST OVERNIGHT. EVEN A FEW HOLES IN THE EXPANSIVE
MID/HIGH CLOUDS AS THE SHORTWAVE RIDGING ALOFT IS TRYING TO TAKE
HOLD. DEEPER MOISTURE OFF TO THE SOUTHWEST WHERE CLOUD CEILINGS
AROUND 5KFT AND PATCHES OF WEAK RADAR ECHO STILL ENOUGH FOR AN
OCCASIONAL OBSERVATION OF PRECIP HITTING THE GROUND OVER INDIANA.
OVERNIGHT...RUC ISENTROPIC WORK /MAINLY 290-300K LAYER/ SHOWS A
RENEWED SURGE OF MOISTENING/ISENTROPIC LIFT...MAINLY CENTERED ON
300K SFC LIFTING NORTH INTO NRN KY/WRN IND. THIS CORRESPONDS TO
THOSE 5KFT CIGS UPSTREAM. WHILE LOWER LEVEL THETA SFCS TRENDING TO
A DRIER FETCH OUT OF THE SERN CONUS...THE MID LEVEL LIFT/MOISTURE
MAY BE ENOUGH FOR A BRIEF PERIOD OF FZRA/SLEET/SN OVER FAR WRN
SECTIONS LATER TONIGHT. BUT ADMITTEDLY THE CHANCES ARE VERY
SMALL...WHICH IS RIGHT WHERE THE FORECAST LIES...ABOUT 20 PERCENT.
OVERCOMING QUITE A DRY SUB-CLOUD LAYER WOULD BE TOUGH...AND RIGHT
NOW RADAR ECHO OFF CVG TDWR AND KILN WSR-88D NOWHERE CLOSE TO
BEING HIGH ENOUGH TO DO SO.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS AN UPPER LEVEL PATTERN AMPLIFIES AND A DEEP UPPER LOW DIGS
INTO THE CENTRAL PLAINS...THIS WILL RESULT IN A RAPIDLY DEEPENING
SURFACE LOW OVER THE OZARKS TOMORROW. THE LOW WILL OCCLUDE AS IT
DRIFTS NORTH INTO IOWA THROUGH FRIDAY. THERE WILL BE SOME WEAK
ISENTROPIC LIFT ACROSS AREAS NEAR AND WEST OF I-75 THROUGH EARLY
THURSDAY. WITH A RELATIVELY SATURATED COLUMN...THIS MAY BE ENOUGH
TO PRODUCE SOME LIGHT PRECIP ACROSS THE WESTERN CWA THROUGH
TOMORROW MORNING.
WARM AIR ADVECTION INCREASES FROM THE SOUTHWEST BY TOMORROW
AFTERNOON...WITH PRECIPITATION BECOMING LIKELY ACROSS THE SOUTHWESTERN
PART OF THE FORECAST AREA BY LATE TOMORROW. THERMAL PROFILES BY
THIS TIME WILL SUPPORT ALL RAIN. RAIN WILL OVERSPREAD THE REGION
FROM SOUTHWEST TO NORTHEAST THURSDAY NIGHT. 70-KT LOW LEVEL JET
WILL ENHANCE LOW LEVEL UPGLIDE AND CONVERGENCE...WHICH COMBINED
WITH PRECIPITABLE WATER VALUES NEAR ONE INCH...WILL LIKELY RESULT
IN HEALTHY RAIN AMOUNTS WHICH MAY APPROACH ONE INCH IN SPOTS.
A TIGHT PRESSURE GRADIENT WILL RESULT IN A STIFF EAST- SOUTHEAST
WIND THURSDAY NIGHT. HOWEVER A VERY STRONG LOW LEVEL INVERSION AND
LACK OF ANY INSTABILITY WILL PREVENT STRONG WINDS ALOFT FROM
MIXING DOWN...ALTHOUGH GUSTS TO 35 MPH ARE POSSIBLE.
PRECIPITATION WILL SHIFT TO THE NORTHEAST ON CHRISTMAS DAY AS THE UPPER
LOW MOVES IN FROM THE WEST. WILL LIKELY SEE SCATTERED SHOWERS
REDEVELOP DURING THE AFTERNOON DUE TO THE PROXIMITY OF THE UPPER
LOW. BULK OF COLD AIR ADVECTION DOES NOT MOVE IN UNTIL LATE
FRIDAY...WHEN BEST MOISTURE AND LIFT WILL BE PUSHING EAST OF THE
FORECAST AREA. WHILE THERE MAY BE A FEW LIGHT SHOWERS CHANGING TO
LIGHT SNOW SHOWERS OR FLURRIES FRIDAY NIGHT...THE CHANCE FOR ANY
MEASURABLE SNOW FRIDAY NIGHT CONTINUES TO LOOK SLIM. WINDS ARE
EXPECTED TO GUST TO 30 TO 35 MPH ON FRIDAY BEFORE DIMINISHING TO 10
TO 15 MPH FRIDAY NIGHT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AREA WILL BE UNDER A DRY SLOT SATURDAY BEHIND A COLD FRONT AND
AHEAD OF AN EXTENSIVE UPPER LOW. THERE WILL BE A CHANCE OF SNOW
SHOWERS SUNDAY AND MONDAY AS THE UPPER LOW TRAVELS THROUGH THE
WESTERN GREAT LAKES TO OHIO. IT APPEARS THAT THE FETCH OFF LAKE
MICHIGAN WILL BE FAVORABLE FOR ENHANCEMENT OF THE SNOW SHOWERS ON
MONDAY...ESPECIALLY OVER NORTHERN COUNTIES. HIGH PRESSURE WILL
PROVIDE DRY CONDITIONS AS IT MOVES ACROSS THE REGION ON TUESDAY
AND WEDNESDAY.
COLD WEATHER WILL PERSIST THROUGH THE PERIOD AND WE MAY NOT SEE
TEMPERATURES REACH NORMAL VALUES AT ALL. HIGHS ARE FORECAST TO BE IN
THE 20S AND 30S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
CLEAR SKIES CURRENTLY ACROSS EASTERN PORTIONS OF OUR FA BUT AN AC
DECK IS TRYING TO SPREAD BACK IN FROM THE SOUTHWEST. MODELS ARE
INDICATING THAT THESE MID CLOUDS MAY HAVE A TOUGH TIME MAKING IT
MUCH FARTHER EAST AS THEY ENCOUNTER A DRIER AIRMASS SO KCMH AND
KLCK MAY REMAIN ON THE EDGE OF THE CLEARING THROUGH MUCH OF THE
MORNING. 00Z NAM AND GFS HAVE TRENDED A LITTLE SLOWER WITH ONSET
OF PCPN FOR TONIGHT. HOWEVER...WHILE BETTER FORCING REMAINS OFF
TO OUR WEST THROUGH 06Z...SOME WEAKER ISENTROPIC LIFT WILL DEVELOP
ACROSS OUR AREA LATER THIS AFTERNOON INTO THIS EVENING. THIS COULD
SUPPORT A FEW SHOWERS BUT CHANCE APPEARS LOW ENOUGH TO LEAVE TAFS
DRY THROUGH THIS AFTERNOON. WILL THEN ALLOW FOR A VCSH TO WORK
ITS WAY IN FROM THE WEST THROUGH THE EVENING HOURS WITH STEADY
PCPN AND LOWERING CIGS/VSBYS MOVING INTO THE WEST TOWARD 06Z.
OUTLOOK...MVFR/IFR CIGS WILL LINGER THROUGH FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...PARKER
NEAR TERM...BINAU
SHORT TERM...PARKER
LONG TERM...CONIGLIO
AVIATION...JGL
