-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 230559
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
159 AM EDT THU MAY 23 2013

.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE THROUGH THE REGION OVERNIGHT. A
SECONDARY FRONT WILL BRING A CHANCE OF RAIN AGAIN ON THURSDAY.
MUCH COOLER AIR WILL MOVE INTO THE REGION ON FRIDAY... AS HIGH
PRESSURE BUILDS INTO THE OHIO VALLEY THROUGH SATURDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MORE WIDESPREAD SHOWER AND ISOLATED THUNDERSTORM ACTIVITY IS
BEGINNING TO EXIT NORTHEASTERN PORTIONS OF THE FA. A THIN LINE OF
SHOWERS ACROSS THE NORTHERN PORTIONS OF THE FA IS ASSOCIATED WITH
A WEAK FRONTAL BOUNDARY. THERE IS NOT REALLY A PRONOUNCED
TEMPERATURE DIFFERENCE OF WIND SHIFT WITH THIS BOUNDARY.
ADDITIONAL SHOWER ACTIVITY IS WORKING INTO WESTERN PORTIONS OF THE
FA. EXPECT THIS ACTIVITY TO CONTINUE TO MOVE TO THE EAST AND THEN
GRADUALLY WEAKEN SOME THROUGH THE NIGHT.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
INITIAL FRONT KIND OF WASHES OUT EARLY THURSDAY...BUT A SECONDARY
FRONT DROPS IN BEHIND IT. IN ADDITION...A PRETTY SHARP H5 TROF
SWINGS UP THE OHIO VALLEY. THIS SHOULD PROVIDE THE BEST LIFT OF
THIS SYSTEM. INSTABILITY WILL BE VERY WEAK...BUT JUST
ENOUGH FOR SOME RISK OF THUNDER. THE AIR MASS ALOFT WILL BE
INCREASINGLY COLD...HELPING TO LEAD TO THE POSSIBILITY OF
CONVECTIVE SHOWERS. SO UPPED POPS ON THU. WENT CATEGORICAL IN THE
NW...LIKELY POPS FOR A MUCH OF THE REST OF THE FA.

CONVECTION WILL LINGER INTO THU EVENING AS THE S/W CONTINUES TO
SWING THROUGH. HIGH PRESSURE WILL BUILD IN FOR FRIDAY. COULD SEE
SOME FAIR WX CU AS COLD AIR ALOFT KICKS THE LAPSE RATES OVER.
SKIES SHOULD THEN CLEAR FOR FRIDAY NIGHT.

HIGHS ON THURSDAY WILL HAVE A WIDE RANGE. THIS IS DUE TO THE COLD
FRONT PUSHING THRU THE REGION. HIGHS IN THE NW WILL BE LIMITED TO
THE UPPER 60S...WHILE IN THE SE THEY WILL PUSH INTO THE MID 70S.
LOWS WILL FALL PACK INTO THE 40S THURSDAY NIGHT AND ONLY WILL
REBOUND INTO THE LOWER TO MID 60S.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
LARGE AREA OF HIGH PRESSURE WILL HOLD SWAY OVER THE OHIO VALLEY AND
GREAT LAKES REGION FOR THE WEEKEND. PREVIOUS MODELS WERE SHOWING A
NARROW TONGUE OF QPF/POPS PUSHING SOUTHEAST FROM THE IA/IL AREA BUT
WERE KEYING ON A H5 S/W CUTTING THROUGH THE ESTABLISHED RIDGE AND
DISSIPATING AS IT WENT DOWNSTREAM INTO THE OHIO VALLEY. THIS
SCENARIO IS STILL A POSSIBILITY BUT SEEN AS A DISTANT OUTLIER AT
THIS TIME.

GFS IS STILL SHOWING THESE H5 DISTURBANCES UNDERCUTTING THE RIDGE
AND NOSING INTO THE REGION MON/TUES WHERE EUROPEAN IS SOMEWHAT
SIMILAR WITH AN ELEVATED CONVERGENT LAYER BUT MUCH FURTHER SOUTHWEST
AND OUT OF CWA.

SURFACE HIGH MOVES OFFSHORE EARLY NEXT WEEK WITH DRYING SOUTHEAST
SURFACE WINDS OVER THE OHIO VALLEY. UPPER LEVEL FLOW IS SHOWING A
BROADENING OF THE H5 RIDGE AS IT MOVES OVER THE EASTERN THIRD OF THE
COUNTRY. HAVE INCREASED THE CHANCES FOR MID LEVEL DISTURBANCES TO
UNDERCUT THE RIDGE AT THIS TIME BUT KEEP THE THREAT FOR SHOWERS LOW
AT 20% TOWARDS THE MIDDLE OF NEXT WEEK.

EXPECT A GRADUAL WARMUP EACH DAY...STARTING IN THE UPPER 60S TO
AROUND 70 SATURDAY...WARMING TO NEAR 80/LOW 80S BY WED. PM LOWS WILL
BE COMFORTABLY COOL IN THE 40S THROUGH MON MORNING UNDER A DRY
AIRMASS AND THEN WARM TO THE CLIMATOLOGICAL NORMS IN THE MID 50S BY
MID WEEK.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
UPPER LEVEL LOW CENTERED OVER THE WESTERN GREAT LAKES THIS MORNING
WILL PIVOT SOUTHEAST ACROSS OUR REGION THROUGH THE DAY. THIS
FEATURE WILL BE FOLLOWED BY A MORE VIGOROUS DISTURBANCE IN THE
NORTHWEST FLOW ALOFT AND WILL BE ASSOCIATED WITH A STRONGER COLD
FRONT WHICH IS FORECAST TO PASS SOUTHEAST ACROSS THE TAF SITES
LATE THIS AFTERNOON INTO THIS EVENING.

FIRSTLY...A WEAK COLD FRONT IS POISED TO PASS ACROSS THE TAF SITES
BETWEEN 09Z AND 15Z THIS MORNING. SCATTERED SHOWERS ALONG AND
AHEAD OF THE FRONT WILL LIKELY AFFECT THE TAF SITES WITH SOME MVFR
VSBYS. INITIAL AVIATION PROBLEM EARLY THIS MORNING IS WHETHER
PREDOMINATE STRATUS WILL FORM AT THE TAF SITES...ESPECIALLY AT
KDAY...KILN...KCMH...AND KLCK. LOW STRATUS IS FLOATING AROUND IN
THIS REGION BUT WITH SHOWERS AND STILL SOME LOW LEVEL MIXING...IT
IS UNCLEAR IF THIS WILL FORM INTO A PERMANENT DECK. AS SUCH...HAVE
LEFT A SCATTERED LOW CLOUD AT THESE TAF SITES AND WILL MONITOR
TRENDS TO SEE IF THIS BECOMES PERMANENT. IF THEY DO...CEILINGS
WILL LIKELY BE IN THE 6-8 HUNDRED FOOT RANGE.

FROM LATE THIS MORNING INTO THIS AFTERNOON...LARGE SCALE ASCENT
ASSOCIATED WITH THE MAIN UPPER LOW WILL COMBINED WITH DAYTIME
HEATING/INSTABILITY TO PRODUCE WIDESPREAD SHOWERS. CAN NOT RULE
OUT SOME EMBEDDED THUNDER...BUT THIS WILL BE TOO SPORADIC TO
PINPOINT IN THE TAFS AT THIS TIME SO HAVE LEFT OUT. SHOWERS SHOULD
BECOME A LITTLE HEAVIER OUT AHEAD OF THE SECONDARY COLD FRONT THIS
AFTERNOON AND EVENING. AND WITH MOISTENING LOW LEVELS...HAVE GONE
WITH PREDOMINANT MVFR CONDITIONS.

FOR TONIGHT...COLD FRONT WILL SLIDE SOUTHEAST AND WILL RESULT IN
WINDS SWITCHING TO THE NORTH...WHICH WILL BECOME GUSTY AROUND 25
KNOTS. DILEMMA IMMEDIATELY BEHIND THE COLD FRONT IS HOW LOW
CEILINGS WILL DROP IN THE CAA PATTERN. SOME DETERMINISTIC AND
ENSEMBLES SUGGEST THAT CEILINGS COULD DROP INTO IFR FOR A
TIME...ESPECIALLY UP IN THE KCMH/KLCK AREA. HAVE KEPT CEILINGS IN
THE 1000-1500 RANGE AT THIS TIME AND WILL ADDRESS THIS AGAIN WITH
THE NEXT TAF PACKAGE AT 12Z. OTHERWISE...ONCE THE SECONDARY
DISTURBANCE PASSES SOUTHEAST...MUCH DRIER AIR WILL FILTER INTO THE
REGION UNDER STRONG SUBSIDENCE BETWEEN 09Z AND 12Z. AS SUCH...ANY
LOW LEVEL STRATUS SHOULD SCOUR OUT AND/OR PUSH SOUTHEAST AWAY FROM
THE REGION...LEAVING MOSTLY CLEAR SKIES BY 12Z FRIDAY.


OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...SITES
NEAR TERM...NOVAK
SHORT TERM...SITES
LONG TERM...FRANKS
AVIATION...HICKMAN