-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 131717
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
117 PM EDT MON MAY 13 2013

.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST THROUGH THE OHIO VALLEY TODAY.
SOUTHERLY FLOW WILL THEN RETURN TO THE REGION THROUGH THE REST OF
THE WEEK. THIS FLOW WILL BRING WARMER AND MORE MOIST AIR TO THE
REGION WHICH WILL GET WRUNG OUT AS A COLD FRONT PASSES TO THE
SOUTH ON THURSDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LIGHT RETURNS ON RADAR HAVE BEEN OBSERVED FOR SEVERAL HOURS THIS
MORNING ACROSS THE NORTHERN AND NORTHEASTERN PARTS OF THE CWA. SO
FAR...NO PRECIPITATION REPORTS HAVE BEEN RECEIVED IN THE ILN
CWA...AND SURFACE DEWPOINTS IN THE UPPER 20S SUGGEST THAT THESE
ECHOES ARE HAVING A HARD TIME MAKING IT TO THE GROUND.

THOUGH MOST OF THE CWA IS RELATIVELY CLEAR...THE AXIS OF CLOUDS
AND RADAR ECHOES IS IN AN AREA THAT SOME MODELS HAVE SHOWN AS
FAVORABLE FOR LIGHT RAIN SHOWER DEVELOPMENT THIS AFTERNOON.
TEMPS ARE WARMING UP ON THE WARMER END OF THE MODEL CURVE...SO MAX
TEMPS WILL BE INCREASED SLIGHTLY WITH THIS UPDATE. WITH THE AXIS
OF COLDER AIR ALOFT STILL IN CENTRAL OHIO THROUGH
PENNSYLVANIA...SOME WEAK INSTABILITY WILL EXIST. SO...A VERY
LIMITED AREA OF 20-POP HAS BEEN INTRODUCED TO THE
FORECAST...GENERALLY IN THE 18Z-21Z TIME FRAME IN THE FAR EASTERN
CWA.

PREVIOUS DISCUSSION >
CLOUD COVER WILL DRIFT EASTWARD THIS MORNING. A WEAK SURFACE LOW
IS PROGGED TO MOVE SOUTHEAST AND THE GFS AND EUROPEAN ARE SHOWING
SOME SPRINKLES POSSIBLE IN SOUTHEAST OHIO THIS AFTERNOON. AM NOT
SEEING ANY OTHER SUPPORT FOR THIS SCENARIO OTHER THAN THE MOVEMENT
OF THE LOW. AN APPROACHING THERMAL TROUGH COULD HELP GIVE SOME
INSTABILITY TO SUPPORT A BRIEF SHOWER...BUT THE OVERALL AIRMASS
WILL BE WARMING THIS AFTERNOON. LEFT MENTION OF SPRINKLES AND/OR
LOW CHANCE SHOWERS FOR THE SCIOTO VALLEY OUT OF THE FORECAST
TODAY.

CLOUDS AND EXPECTED CU TODAY WITH THE THERMAL TROUGH WILL HELP
LIMIT HIGHS TO THE UPPER 50S AND LOW 60S FOR ANOTHER RELATIVELY
COOL DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE WILL MOVE EAST TONIGHT. AN AREA OF LIFT WILL OCCUR
ON THE BACK SIDE OF THE DEPARTING HIGH AND RESULT IN INCREASED
CLOUD COVER TONIGHT...WHICH WILL HELP SLOW DOWN THE TYPICAL DROP-
OFF OF TEMPERATURES OVERNIGHT. SOUTHERLY FLOW WILL REMAIN OVER THE
OHIO VALLEY THROUGH THE PERIOD AND HELP BRING A NICE WARMUP AND
MORE MOISTURE TO THE REGION.

A FRONTAL BOUNDARY WILL LAY OUT ON A WSW-ENE ORIENTATION THROUGH
NORTHERN OHIO WEDNESDAY AFTERNOON AND EVENING. SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG THIS BOUNDARY AND CONTINUE AS IT
SLOWLY MOVES SOUTH TOWARDS THE OHIO RIVER OVERNIGHT WEDNESDAY.
DID NOT GO HIGHER THAN CHANCE WITH THIS FEATURE GIVEN THAT THE
COVERAGE FROM ONE MODEL TO THE NEXT IS SOMEWHAT SPOTTY. THINK THAT
HIGH TEMPERATURES ON WEDNESDAY MAY BE OPTIMISTICALLY TOO WARM OVER
NORTHERN CWA GIVEN THE INCREASED THREAT FOR PRECIPITATION.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
MID LEVEL WESTERLY FLOW TO DEVELOPING ACRS THE GREAT LAKES WITH
E-W ORIENTED FRONTAL BOUNDARY TO LAY OUT ALONG THE SRN PERIPHERY
OF THE WESTERLIES. NUMERICAL MODEL SOLNS DIFFER ON EXACTLY HOW FAR
SOUTH THIS FRONT WILL MAKE IT. GENERAL CONSENSUS WUD SUGGEST THE
FRONT STALLS NEAR CENTRAL OHIO. EXPECT THUNDERSTORMS TO DEVELOP
SOUTH WED EVENING ACRS ILNS FA. WILL GRADE POPS FROM HIGH CHANCE
NORTH TO LOW CHANCE FAR SOUTH OVERNIGHT WEDNESDAY. WITH THE FRONT
LAYING OUT ACRS THE AREA AND MID LEVEL S/W MOVING THRU THE OHIO
VALLEY... UNSETTLED WEATHER TO CONTINUE ACRS THE REGION
THURSDAY/THURSDAY NIGHT. HAVE ABOVE NORMAL TEMPS CONTINUING
THURSDAY WITH HIGHS FROM THE UPPER 70S NW TO THE LOWER 80S SE.

SOME EVIDENCE SHOWING FRONTAL BOUNDARY LIFTING NORTH FRIDAY
NIGHT/SATURDAY. SOME UNCERTAINTY EXISTS IN THIS TIME FRAME ON HOW
QUICK THE FRONT LIFTS. WILL CARRY CHANCE POPS FRIDAY AND THEN
DIMINISH POPS TO SLIGHT CHC FRIDAY NIGHT/SAT. WILL SHOW THE HIGHEST
POPS ACRS THE NORTH CLOSER TO THE FRONTAL BOUNDARY. FCST HIGHS ON
FRIDAY FROM THE MID/UPR 70S NORTHWEST TO NEAR 80 SE.

WILL DRY THE REGION OUT FOR A BRIEF PERIOD LATER SATURDAY
NIGHT/EARLY SUNDAY WITH MID LEVEL RIDGING BUILDING EAST INTO THE
OHIO VALLEY. WILL THEN ALLOW CHC POPS FOR CONVECTION TO SPREAD BACK
IN FROM THE WEST LATER SUNDAY INTO MONDAY WITH THE APPROACH OF A
FRONTAL SYSTEM.

TEMP WISE...HAVE ABOVE NORMAL TEMPS EXPECTED TO CONTINUE NEXT WEEKEND
WITH HIGHS IN THE UPPER 70S NW TO LOWER 80S SE. THESE TEMPS COULD
END BEING UP A LTL COOLER IF THE FRONTAL RETREAT NORTH DOES NOT
OCCUR AND A MORE STEADY RAIN AND EXTENSIVE CLOUD COVER IS OBSERVED
SAT/SUN.

&&

.AVIATION /17Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
RIDGING WILL GRADUALLY BEGIN BUILDING INTO THE REGION OVER THE
NEXT 24 HOURS. TODAY...DIURNAL CUMULUS DEVELOPMENT AND SLIGHTLY
GUSTY WESTERLY WINDS WILL BE THE MAIN WEATHER IMPACTS. ALTHOUGH
THERE IS A VERY SLIGHT CHANCE OF A SHOWER IMPACTING THE COLUMBUS
TAF SITES OVER THE NEXT FEW HOURS...THIS APPEARS TOO INSIGNIFICANT
TO MENTION IN THE TAFS.

DIURNAL CLOUDS SHOULD MOSTLY DISSIPATE TONIGHT...BUT HIGH CLOUDS
WILL BEGIN TO MOVE IN AND LOWER THROUGH THE OVERNIGHT HOURS.
ADDITIONAL CUMULUS / STRATOCUMULUS DEVELOPMENT IS EXPCTED ON
TUESDAY MORNING...WITH WIND GUSTS OF VALUES UP TO 20 KNOTS.

GIVEN THE CLOUD COVER MOVING IN OVERNIGHT...FOG DID NOT APPEAR
PARTICULARLY FAVORABLE.

OUTLOOK...THUNDERSTORMS ARE POSSIBLE FROM WEDNESDAY NIGHT THROUGH
FRIDAY.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...FRANKS
NEAR TERM...FRANKS/HATZOS
SHORT TERM...FRANKS
LONG TERM...AR
AVIATION...HATZOS