FXUS61 KILN 241802
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
102 PM EST THU DEC 24 2009
.SYNOPSIS...
A DEEP SURFACE LOW WILL OCCLUDE OVER THE OZARKS TODAY...AS A
STRONG UPPER TROUGH DIGS INTO THE SOUTHERN AND CENTRAL PLAINS. THE
SURFACE LOW WILL MEANDER NORTHWARD INTO IOWA THROUGH FRIDAY
NIGHT...SENDING AN OCCLUDED FRONT INTO THE OHIO VALLEY BY EARLY
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ISENTROPIC LIFT IN THE MID LVLS MAY BRING SOME SHOWERS...MAINLY
TO THE WRN CWFA...THIS AFTN. BELIEVE COVERAGE WILL BE LESS THAN
PREVIOUSLY FORECASTED...SO HAVE CUT BACK POPS. SKIES WILL REMAIN
MOSTLY CLOUDY...EXCEPT ACRS THE ERN ZONES WHERE SOME PEAKS OF SUN
WILL BE POSSIBLE. SHALLOW COLD AIR WILL BE SLOW TO ERODE...BUT ALL
LOCATIONS ARE EXPECTED TO NUDGE ABOVE FREEZING BY LATE IN THE DAY.
HIGHS WILL RANGE FROM THE MID 30S NORTH TO THE UPPER 40S FAR
SOUTHWEST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
SURFACE LOW TRACKS NORTH TO NEAR ST LOUIS OVERNIGHT...WITH STRONG
LOW LEVEL FIELD SPREADING NORTHWARD TO THE EAST OF THE LOW. STRONG
CONVERGENCE AND ISENTROPIC LIFT WILL ALLOW FOR A WIDESPREAD AREA
OF RAIN WHICH WILL OVERSPREAD THE ENTIRE CWA FROM SOUTHWEST TO
NORTHEAST OVERNIGHT THURSDAY AND EARLY FRIDAY. 850 HPA-WINDS WILL
BE VERY STRONG...POTENTIALLY IN EXCESS OF 75-KT...BUT LOW LEVEL
INVERSION WILL BE MUCH TOO STRONG TO ALLOW ANY SIGNIFICANT
MOMENTUM TRANSFER TO THE GROUND. STILL...WITH VERY TIGHT GRADIENT
IN PLACE AND WINDS UP TO 60-KT AT 925 HPA...EXPECT A STIFF EAST-
SOUTHEAST WIND THURSDAY NIGHT AND FRIDAY MORNING WITH GUSTS UP TO
40 MPH POSSIBLE AT TIMES.
OCCLUDED FRONT WILL LIFT NORTHEAST ACROSS THE CWA FRIDAY
MORNING...BRINGING AN END TO THE WIDESPREAD RAIN ACROSS THE
SOUTHWEST BY MID FRIDAY MORNING...AND ACROSS CENTRAL OHIO BY EARLY
AFTERNOON. WILL STILL BE PLENTY OF LOW LEVEL MOISTURE BEHIND THE
FRONT...AND WITH WEAK LOW LEVEL CONVERGENCE IN PLACE...EXPECT
SCATTERED RAIN SHOWERS TO PERSIST THROUGH FRIDAY AFTERNOON. COLD
AIR ADVECTION DOES NOT GET GOING UNTIL EARLY FRIDAY EVENING...SO
ANY CHANGE OVER TO SNOW WILL NOT OCCUR UNTIL AFTER DARK FRIDAY.
LITTLE IF ANY SNOW ACCUMULATION WILL OCCUR WITH THIS ACTIVITY.
LINGERING LOW LEVEL MOISTURE AND UPPER LOW MOVING IN FROM THE WEST
WILL MAINTAIN A CHANCE FOR SCATTERED SNOW SHOWERS SATURDAY AND
SATURDAY NIGHT...WITH ANY ACCUMULATION LIMITED TO A HALF INCH OR
LESS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
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 /18Z THURSDAY THROUGH TUESDAY/...
LOW PRESSURE OVER SRN ARKANSAS THIS AFTN WILL DEEPEN AS IT MOVES
NORTH TO SE IOWA BY FRIDAY MORNING. THEREAFTER...THE LOW WILL
ROTATE OVER OVER THE UPPER MS RIVER VLY IN TANDEM WITH ITS PARENT
UPR LEVEL CLOSED LOW THROUGH SATURDAY. THIS LOW WILL PUSH AN
OCCLUDED FRONT ACRS THE FORECAST AREA BETWEEN 18Z FRIDAY AND 00Z
SATURDAY.
IN THE MEANTIME...WAA TO OUR WEST WILL CAUSE SOME SCATTERED
SHOWERS TO SKIM THE WRN TAF SITES THROUGH 06Z. THEREAFTER...A VERY
STRONG...MOIST LOW LEVEL 850 MB JET IN CONJUNCTION WITH UPPER LEVEL
SUPPORT WILL BRING WIDESPREAD LIGHT TO MODERATE RAIN TO THE TAF
SITES OVERNIGHT INTO FRIDAY MORNING. CIGS WILL LOWER INTO THE MVFR
CATEGORY WITH POCKETS OF IFR CIGS POSSIBLE. VSBYS SHOULD STAY IN
THE MVFR CATEGORY WITH THE RAIN. OF GREATER SIGNIFICANCE OVERNIGHT
INTO FRIDAY MORNING WILL BE THE POTENTIAL FOR LOW LEVEL WIND SHEAR
AS 850 MB JET APPROACHES 80 KNOTS. THE DIFFERENCE IN WIND
DIRECTION BETWEEN THE SFC AND 2000 FEET WILL BE NEAR 60 DEGREES
ALONG WITH AN INCREASE IN SPEED OF ABOUT 40 KNOTS. HAVE PLACED LOW
LEVEL WIND SHEAR AT THE TAF SITES...KNOWING THAT IT MAY START A
LITTLE SOONER AND LAST A LITTLE LATER THAN CURRENTLY FORECAST. AS
STATED PREVIOUSLY...AFOREMENTIONED OCCLUDED FRONT WILL MOVE ACROSS
THE TAF SITES BETWEEN 18Z AND 00Z. SHOWERS WILL ACCOMPANY THE
FRONT FOLLOWED BY A RAPID DECREASE IN PCPN COVERAGE BEHIND THE
FRONT. WINDS WILL REMAIN GUSTY OVERNIGHT INTO FRIDAY WITH WIND
GUSTS OF 25 TO 35 KNOTS LIKELY.
OUTLOOK...MVFR CIGS POSSIBLE FRIDAY NIGHT INTO MONDAY. MVFR/IFR
VSBYS POSSIBLE SUNDAY INTO SUNDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HAWBLITZEL/HICKMAN
NEAR TERM...HAWBLITZEL/HICKMAN
SHORT TERM...HAWBLITZEL
LONG TERM...CONIGLIO
AVIATION...HICKMAN
