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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 191917
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
317 PM EDT SUN MAY 19 2013

.SYNOPSIS...
-- Changed Discussion --
A WARM AND MOIST AIRMASS WILL BE IN PLACE TONIGHT AND INTO THE
FIRST HALF OF THE WEEK AS MID LEVEL RIDGING BUILDS ACROSS THE
REGION. SHOWERS AND THUNDERSTORMS WILL BECOME POSSIBLE MONDAY
NIGHT THROUGH MID WEEK AS THE RIDGE SHIFTS EAST OF OUR AREA AND
LOW PRESSURE SLOWLY SPINS EAST ACROSS THE UPPER MID WEST.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AN UPPER LEVEL DISTURBANCE OVER WEST VIRGINIA INTERACTING WITH A
WARM AND MOIST AIRMASS ACROSS OUR AREA IS PROVIDING FOCUS FOR
DIURNAL SHOWERS WITH ISOLATED THUNDERSTORMS THIS AFTERNOON. MID
LEVEL RIDGING BUILDING EAST ACROSS THE REGION THIS AFTERNOON AND
EVENING WILL BRING A QUICK END TO MOST ACTIVITY BY THE EARLY
EVENING. HIGHER RES MODELS ARE INDICATING SOME REDEVELOPMENT OF
SHOWERS LATE TONIGHT AS A WEAK LOW LEVEL JET DEVELOPS JUST EAST OF
THE MID LEVEL RIDGE AXIS. BASED ON THE MOIST AIRMASS IN
PLACE...AND THE FAIR NUMBER OF MODELS SHOWING THIS FEATURE...HAVE
ADDED SLIGHT CHANCE POPS OVERNIGHT MAINLY ACROSS THE SOUTH.

MAJORITY OF CLOUD COVER IS CURRENTLY DIURNALLY DRIVEN. AND ASIDE
FROM ISOLATED SHOWERS TONIGHT...SKIES WILL BE MOSTLY CLEAR. THE
INHERENT AIRMASS OVER OUR AREA TONIGHT WILL BE VERY SIMILAR TO
THAT SEEN ACROSS SOUTHERN ILLINOIS AND WESTERN KENTUCKY THIS
MORNING. THIS AIRMASS PRODUCED AREAS OF FOG AND WITH NO MAJOR
CHANGES FORESEEN IN THIS AIRMASS...AREAS OF FOG WILL BE LIKELY
ACROSS OUR AREA TONIGHT AS WELL. WILL MENTION IN THE HWO THE
POTENTIAL FOR LOCALLY DENSE FOG TO DEVELOP TONIGHT.

CLEAR SKIES SHOULD ALLOW FOR TEMPERATURES TO DROP OFF INTO THE
LOWER 60S FOR THE MOST PART ACROSS ALL ZONES.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
-- Changed Discussion --
THE MID LEVEL RIDGE WILL LIKELY KEEP ANY FORCING OUT OF OUR AREA
ON MONDAY AND INTO MONDAY EVENING. MODELS DO SHOW A VERY HIGH AMOUNT
OF CONDITIONAL INSTABILITY ACROSS THE AREA MONDAY AFTERNOON...SO
IF ANY BOUNDARIES WERE TO MOVE INTO OUR AREA FROM OVERNIGHT
CONVECTION TO OUR WEST...THIS COULD BE PROBLEMATIC FOR THE CURRENT
FORECAST OF NO POPS ON MONDAY. HOWEVER AM MORE CONFIDENT IN A DRY
FORECAST FOR MONDAY INTO MONDAY EVENING BASED ON PERSISTENCE OF
THE QUIET...YET UNSTABLE CONDITIONS OCCURRING THIS AFTERNOON UNDER
THE MID LEVEL RIDGE TO OUR WEST-SOUTHWEST. 850 HPA TEMPS RISING INTO
THE UPPER TEENS WILL ALLOW TEMPERATURES TO RISE INTO THE UPPER
80S ACROSS THE AREA MONDAY AFTERNOON. THE MAIN INHIBITING FACTOR
FOR TEMPERATURES NOT RISING INTO THE LOWER 90S WILL BE THE LACK OF
DEEP MIXING DURING THE DAY.

ON MONDAY NIGHT THE MID LEVEL RIDGE SHIFTS EAST AS LOW PRESSURE
SLOWLY MOVES EAST IN TANDEM ACROSS THE NORTHERN PLAINS. EMBEDDED
DISTURBANCES RIDING AROUND THE BASE OF THE TROUGH EXTENDING SOUTH
OF THE LOW IN THE PLAINS WILL HELP TO TRIGGER WAVES OF CONVECTION
TO OUR WEST MONDAY NIGHT THROUGH THE END OF THE SHORT TERM TIME
PERIOD. WENT AS FAR AS TRYING TO CAPTURE THE FIRST WAVE MONDAY
NIGHT INTO TUESDAY MORNING...AS THE NMM...ARW...CMC REG...AND NAM
ALL INDICATE A LINE OF CONVECTION HOLDING TOGETHER EARLY TUESDAY
MORNING AS IT APPROACHES OUR WESTERN ZONES. BASED ON THE NOCTURNAL
...AND LIKELY LOW LEVEL JET DRIVEN NATURE OF THIS
FEATURE...AM FORECASTING IT TO WEAKEN AS IT ENTERS OUR FORECAST
AREA FROM THE WEST AFTER DAYBREAK TUESDAY. THERE WILL LIKELY BE
INCREASING CLOUD COVER MONDAY NIGHT AS WELL AS WEAK RETURN FLOW.
THIS WILL KEEP TEMPERATURES WELL ABOVE NORMAL...IN THE MIDDLE TO
UPPER 60S FOR LOWS.

BEYOND TUESDAY MORNING INTO TUESDAY EVENING AM FORECASTING HIGHEST
PROBABILITIES FOR SHOWERS AND THUNDERSTORMS CLOSER TO THE BETTER
FORCING ACROSS OUR NORTHWESTERN ZONES. HIGHS TUESDAY WILL BE
DEPENDENT ON CLOUD COVER AND PRECIPITATION. 850 HPA TEMPS ARE STILL
EXPECTED TO BE QUITE WARM...IN THE UPPER TEENS STILL ON TUESDAY.
WITH DEEPER MIXING IN PLACE TUESDAY ANOTHER ROUND OF UPPER 80S
WITH SOME LOW 90S IS EXPECTED ACROSS THE CURRENTLY FORECASTED
SUNNIER AND DRIER SOUTHEAST...AND THE MIDDLE 80S ACROSS THE
CLOUDIER AND HIGHER POPS NORTHWEST.
-- End Changed Discussion --

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --
AN UPPER LEVEL TROUGH WILL DROP DOWN ACROSS THE GREAT LAKES ON
WEDNESDAY AND THEN PIVOT EAST OVER OUR AREA THURSDAY INTO THURSDAY
NIGHT. A WARM AND UNSTABLE AIRMASS WILL BE IN PLACE ACROSS THE
REGION ON WEDNESDAY AS TEMPERATURES PUSH INTO THE LOWER 80S THROUGH
THE AFTERNOON. THE COMBINATION OF THIS AND SOME EMBEDDED SHORT WAVE
ENERGY MOVING THROUGH THE TROUGH WILL RESULT IN AN INCREASING CHANCE
OF THUNDERSTORMS DURING THE DAY. EXPECT SOME DECREASE IN COVERAGE
HEADING INTO WEDNESDAY NIGHT AS WE LOSE SOME OF THE INSTABILITY. A
BETTER CHANCE OF SHOWERS AND THUNDERSTORMS WILL RETURN AGAIN FOR
THURSDAY AS A LOW LEVEL TROUGH AXIS AND AN ASSOCIATED COLD FRONT
DROPS DOWN THROUGH THE AREA. AS THE FRONT MOVES SOUTH...PCPN SHOULD
TAPER OFF TO A FEW SHOWERS THROUGH THURSDAY NIGHT.

HIGH PRESSURE AND A COOLER AIRMASS WILL BUILD DOWN FROM THE NORTH
THROUGH THE DAY ON FRIDAY. THIS WILL LEAD TO SLIGHTLY BELOW NORMAL
TEMPERATURES WITH HIGHS ON FRIDAY IN THE UPPER 60S TO LOWER 70S. THE
AIRMASS WILL THEN SLOWLY MODERATE THROUGH THE WEEKEND AS MID LEVEL
RIDGING BEGINS TO WORK IN FROM THE WEST. BY SUNDAY...TEMPERATURES
WILL BE BACK TO NEAR NORMAL WITH HIGHS PUSHING BACK TOWARD THE MID
70S. WILL MAINTAIN A DRY FORECAST THROUGH THE WEEKEND AT THIS POINT
BUT THE 12Z ECMWF AND TO A LESSER EXTENT THE 12Z GFS ARE HINTING AT
THE POSSIBILITY OF SOME SHORT WAVE ENERGY DROPPING DOWN IN NORTHWEST
FLOW LATE IN THE PERIOD.
-- End Changed Discussion --

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
SCATTERED SHOWERS HAVE DEVELOPED THIS AFTERNOON AS A WEAK
DISTURBANCE ENHANCES INSTABILITY ALONG AN OLD FRONTAL
BOUNDARY...MAINLY CLOSE TO EASTERN SITES ILN CMH AND LCK. SOME OF
THE SHOWERS MAY RESULT IN MVFR CONDITIONS. AN UPPER RIDGE WILL
BUILD IN TONIGHT WHICH WILL HELP TO BRING SHOWERS TO AN END. UNDER
CALM WINDS AND A HUMID AIRMASS...FG AND BR ARE EXPECTED TO REDUCE
VISIBILITIES TONIGHT. VFR CONDITIONS AND SOUTHERLY WINDS ARE
FORECAST AFTER 12Z MONDAY. MODELS PREDICT A MODERATE AMOUNT OF
INSTABILITY FOR MONDAY...BUT FORCING WILL BE WEAK SO KEPT SHOWERS
OUT OF THE FORECAST.

OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM TUESDAY THROUGH
THURSDAY.

&&

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

&&

$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...JGL
AVIATION...CONIGLIO