FXUS61 KILN 091753
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
153 PM EDT FRI MAY 9 2008

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL QUICKLY TRACK ACROSS THE REGION
THIS AFTERNOON AND EVENING. HIGH PRESSURE WILL BRIEFLY BUILD IN
LATE TONIGHT AND WILL REMAIN OVER THE REGION ON SATURDAY. A
STRONG STORM SYSTEM WILL MOVE INTO THE OHIO VALLEY ON SUNDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPR LVL S/WV OVER IOWA/MISSOURI WILL RAPIDLY MOVE EAST TO THE WRN
GREAT LAKES/LOWER OHIO VALLEY REGION BY LATE THIS AFTERNOON...THEN
ACROSS THE FCST AREA THIS EVENING. OPERATIONAL MODELS AND ENSEMBLE
FORECASTS CONTINUE TO INDICATE A QUICK HITTING EVENT THAT WILL
NEED HIGHER CHC/S FOR RAIN. THE COMBINATION OF LARGE SCALE ASCENT
WITH THE S/WV AND DEVELOPMENTAL 925 MB-850 MB CONVERGENCE OVER THE
REGION THIS EVENING HAVE PROMPTED THE NEED TO RAISE POPS INTO THE
LIKELY/CATEGORICAL RANGE. IN REGARDS TO CHC/S FOR
THUNDER...ELEVATED INSTABILITY IS LOOKING MEAGER AND SURFACE BASED
INSTABILITY LATE THIS AFTERNOON WILL BE LOWER DUE TO COOLER THAN
EXPECTED TEMPERATURES. HAVE DROPPED CHC OF THUNDERSTORMS TO A
SLIGHT CHC. THE THREAT FOR THUNDER MAY HAVE TO BE REMOVED WITH
AFTERNOON PACKAGE IF INSTABILITY CONTINUES TO BE LOW.  

HAVE DROPPED HIGH TEMPERATURES 3 TO 4 DEGREES DUE TO PERSISTENT
LOW CLOUD COVER. HAVE KEPT TONIGHTS LOWS INTACT.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE WILL QUICKLY SLIDE EAST ON SATURDAY RESULTING IN A
DRY DAY. THEN A VIGOROUS STORM SYSTEM WILL PUSH INTO THE OHIO
VALLEY FOR THE LATTER PART OF THE WEEKEND. BROUGHT CHANCE POPS IN
FOR LATE SATURDAY NIGHT IN THE WEST WHILE THE EAST MAY REMAIN DRY
WITH EAST SOUTHEAST LOW LEVEL FLOW. BUT AS THE STORM MOVES IN IT
APPEARS THAT THERE WILL BE AN AREA OF SHOWERS LIFTING ACROSS THE
ENTIRE FORECAST AREA ON SUNDAY. THERE IS SOME ELEVATED INSTABILITY
DURING THE MORNING SO INCLUDED A CHANCE OF THUNDERSTORMS. AFTER
THIS INITIAL AREA MOVES THROUGH THERE IS THE POSSIBILITY OF
GETTING SOME BREAKS IN THE CLOUDS AND THUS HEATING BEFORE TRAILING
SURFACE TROUGH MOVES IN LATE IN THE DAY. HOWEVER THERE IS
CONSIDERABLE UNCERTAINTY IN THIS REGARD. NEVERTHELESS SHOWERS AND
SOME STORMS WILL REDEVELOP SUNDAY AFTERNOON AND EVENING WITH
SHOWERS CONTINUING BUT BECOMING LESS NUMEROUS WITH TIME LATE
SUNDAY NIGHT AND MONDAY.

MOS GUIDANCE LOOKED REASONABLE ON SATURDAY AND SATURDAY NIGHT.
HOWEVER HEDGED SLIGHTLY WARMER ON SUNDAY AND SUNDAY NIGHT. USED A
MULTI-MODEL BLEND FOR HIGHS MONDAY.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
UPPER LEVEL RIDGING WILL WORK ACROSS THE OHIO VALLEY EARLY IN THE
PERIOD PROVIDING A RESPITE FROM AN ACTIVE PATTERN. HOWEVER ANOTHER
CLOSED LOW WILL MOVE INTO THE REGION ON WEDNESDAY AND THURSDAY
RESULTING IN MORE UNSETTLED WEATHER. THUNDERSTORM POTENTIAL WILL
BE GREATEST ON WEDNESDAY AFTERNOON AND EVENING. TEMPERATURES...
ESPECIALLY HIGHS...WILL CONTINUE TO BE BELOW NORMAL DURING THIS
TIME FRAME.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE LOWER GREAT
LAKES/OHIO VALLEY REGION THIS EVENING INTO EARLY MORNING. THE
LARGE SCALE LIFT WITH THIS SYSTEM...COMBINED WITH INCREASING LOW
LEVEL CONVERGENCE...WILL PRODUCE SHOWERS AT THE TAF SITES BETWEEN
22Z AND 06Z. ONCE THIS FEATURE PASSES BY TO THE EAST...SHOWERS WILL
COME TO AN END. PLENTY OF MOISTURE REMAINS ACROSS THE REGION IN
THE FORM OF MVFR TO LOCALLY IFR CIGS. CIGS SHOULD STAY IN THE MVFR
CATEGORY WITH THE SHOWERS AS THE AIR WILL MIX SOME. VSBYS WILL
LOWER TO MVFR WITH PERHAPS LOCAL IFR VSBYS POSSIBLE WITHIN
SHOWERS. AVIATION FORECAST BECOMES SOMEWHAT MUDDLED BETWEEN 06Z
AND 12Z. MODELS CONTINUE TO SHOW DRIER AIR ADVECTING INTO THE
REGION DURING THIS PERIOD AS A RIDGE OF HIGH PRESSURE BUILDS INTO
THE REGION. WITH A WET GROUND FROM RECENT RAIN...AND THE
POSSIBILITY OF CLEARING SKIES...FOG MAY FORM. THE SURFACE PRESSURE
GRADIENT SHOULD BE STRONG ENOUGH TO PREVENT THE FOG FROM GETTING
TOO FAR OUT OF HAND. THE EXCEPTION WILL BE KLUK WHERE LIGHTER
WINDS IN THE RIVER VALLEY MAY ALLOW FOR FOG AND VERY LOW STRATUS.

ANY FOG WILL BURN OFF QUICKLY SATURDAY MORNING AS HIGH PRESSURE
MOVES ACROSS THE REGION. SCT-BKN CUMULUS CLOUDS WILL FORM IN THE
HEAT OF THE DAY.
 
OUTLOOK...POTENTIAL FOR MVFR CIGS/VSBYS WITH SHOWERS AND
THUNDERSTORMS SATURDAY NIGHT THROUGH SUNDAY. MVFR CIGS TO LINGER
INTO MONDAY. 

&&

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

&&

$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...
LONG TERM...
AVIATION...HICKMAN