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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 200524
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
124 AM EDT MON MAY 20 2013

.SYNOPSIS...
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.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPPER LEVEL TROF MOVING SLOWLY EAST THRU THE OHIO VALLEY WAS UNDER A
BROAD RIDGE WHICH EXTENDED NORTH THRU THE GREAT LAKES. THIS UPR LEVEL
DISTURBANCE INTERACTING WITH A WARM AND MOIST AIRMASS ACROSS THE REGION
LED TO THE DEVELOPMENT OF ISOLATED TO SCATTERED CONVECTION THIS
AFTN. THIS ACTIVITY WAS DIURNALLY DRIVEN AND ONLY AN ISOLD SHOWER
REMAINS ACRS THE FAR EAST. WILL END THIS ACTIVITY IN THE NEXT HOUR
OR TWO WITH THE LOSS OF DAYTIME HEATING. SOME OF THE HI RES MODELS
WERE SHOWING SOME SHOWER REDEVELOPMENT BUT WITH PROB RATHER LOW HAVE
KEPT THE REMAINDER OF THE NIGHT DRY.

CLOUD COVER IS GIVING WAY TO MOSTLY CLEAR SKY CONDITIONS. THE
AIRMASS OVER OUR AREA PRODUCED AREAS OF FOG LAST NIGHT. THEREFORE...HAVE
HAVE CONTINUED TO MENTION AREAS OF FOG IN THE GRIDS AND THE HWO PRODUCT
OVERNIGHT. DEPENDING ON THE WIND...THE POTENTIAL EXISTS FOR LOCALLY
DENSE FOG AS WELL.

MAINLY CLEAR SKIES SHOULD ALLOW FOR TEMPERATURES TO DROP OFF INTO
THE LOWER AND MIDDLE 60S FOR THE MOST PART ACROSS ALL ZONES.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
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.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
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.

&&

.AVIATION /05Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
DEWPOINTS IN THE 60S ARE AN INDICATION OF THE RELATIVELY HIGH
MOISTURE CONTENT IN THE LOWER-LEVEL AIR MASS. HOWEVER...VISIBILITY
OBSERVATIONS HAVE REMAINED VFR FOR ALMOST ALL LOCATIONS (TAF AND
NON-TAF) SO FAR...AND THE PRESSURE GRADIENT OVER THE REGION WILL
NOT ALLOW WINDS TO SLACK OFF ENTIRELY. SO...IFR FOG IS LOOKING
LESS LIKELY TONIGHT...WITH SOME MVFR VISIBILITY RESTRICTIONS
EXPECTED CLOSER TO MORNING. SHELTERED KLUK WILL STILL LIKELY
EXPERIENCE IFR CONDITIONS.

THERE WILL BE A VERY SMALL CHANCE OF A LIGHT SHOWER OVERNIGHT AND
INTO THE EARLY MORNING HOURS...BUT THE REST OF THE DAY APPEARS
VOID OF FORCING FOR CONVECTION. SO...A DRY SET OF TAFS WILL BE
ISSUED. SSW WINDS MAY GUST TO AROUND 20 KNOTS...AND VFR CUMULUS IS
EXPECTED TO DEVELOP BELOW THE CAP.

OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM TUESDAY THROUGH
THURSDAY.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...LATTO
NEAR TERM...AR
SHORT TERM...LATTO
LONG TERM...JGL
AVIATION...HATZOS