AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
426 PM EDT SAT MAY 25 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 233 PM EDT SAT MAY 25 2013
A WARM FRONT WILL LIFT NORTHEAST ACROSS CENTRAL INDIANA LATE SUNDAY
THROUGH MONDAY EVENING. THE FRONT AND UPPER LEVEL DISTURBANES WILL
HELP BRING SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA THIS
MEMORIAL DAY WEEKEND AND INTO EARLY NEXT WEEK. THE WARM FRONTAL
PASSAGE WILL ALSO BRING A RETURN TO NORMAL TEMPERATURES BY MONDAY
AND ABOVE NORMAL TEMPERATURES IN THE 80S BY TUESDAY. THUNDERSTORM
CHANCES WILL RETURN BY SATURDAY FOLLOWING A DRY MID TO LATE WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 233 PM EDT SAT MAY 25 2013
MAIN CHALLENGE TONIGHT WILL BE POPS AS WARM ADVECTION PATTERN SETS
UP ACROSS CENTRAL INDIANA.
16Z RAPID REFRESH REFLECTIVITY PROGS SEEM TO HAVE A GOOD HANDLE ON
RAIN SHIELD ASSOCIATED WITH UPPER WAVE AND ISENTROPIC LIFT ON THE
305-310 K LEVEL. A WARM FRONT WILL BE APPROACHING FROM THE SOUTHWEST
TOWARD MORNING...AND WAVES WILL CONTINUE TO DROP SOUTHEAST OVERTOP
PLAINS RIDGE. IN ADDITION...850 MILLIBAR FRONTOGENESIS TAKES SHAPE
ACROSS THE FORECAST AREA TONIGHT. EXPECT...CURRENT AREA OF SHOWERS
ACROSS ILLINOIS WILL BE MOVING ACROSS OUR EASTERN COUNTIES AT 00Z
THIS EVENING FOLLOWED BY ADDITIONAL SHOWERS THROUGH THE NIGHT.
CONSALL SUGGESTS BEST POPS WEST CENTRAL NEAR THE BORDER WHICH MAKES
SENSE AS ATMOSPHERE SATURATES DOWN.
MOS AND ALLBLEND TEMPERATURES CLOSE AND LOOK REASONABLE WITH
OVERNIGHT LOWS IN THE UPPER 40S TO MID 50S.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 233 PM EDT SAT MAY 25 2013
MAIN CHALLENGE FOR MEMORIAL DAY WEEKEND THROUGH TUESDAY WILL BE POPS
AS SHOWERS AND THUNDERSTORMS WILL PLACE OUTDOOR ACTIVITIES IN
JEOPARDY ACROSS CENTRAL INDIANA.
MODELS IN GOOD AGREEMENT ON BRINGING A SWATH OF QPF ACROSS CENTRAL
INDIANA ON SUNDAY AS WARM FRONT DRIFTS NORTHEAST TO THE MIDDLE
MISSISSIPPI VALLEY...AND FRONTOGENESIS AT 850 MILLIBARS AND WARM AIR
ADVECTION CONTINUE NORTHEAST OF THE FRONT ACROSS CENTRAL INDIANA.
ALSO...MORE UPPER WAVES WILL MOVE ACROSS AHEAD OF THE APROACHING AND
WEAKENING UPPER RIDGE. THUS...WILL RAISE POPS TO GOOD CHANCE OR
BETTER WITH LIKELY POPS ALONG AND NEAR A CORRIDOR FROM IND-LAF AFTER
18Z. LOOKING AT MOST UNSTABLE CAPE PROGS...WOULD NOT RULE OUT
THUNDER ESPECIALLY SOUTHWEST OF IND...BUT WILL GO AHEAD AND INCLUDE
ISOLATED THUNDER ACROSS ALL COUNTIES. SUNDAY NIGHT AND MONDAY LOOK
TO BE THE MOST ACTIVE PERIOD AS THE WARM FRONT MOVES THROUGH WITH
HIGHEST POPS FROM IND AND NORTH...WHERE CHANCES WILL BE IN THE
LIKELY CATEGORY. MORE USTABLE AIR ALSO ARRIVES WITH THE FRONT...SO
WENT WITH THUNDER ALL ZONES FROM SUNDAY NIGHT ON. POPS WILL BE
DECREASING FROM SOUTH TO NORTH BEHIND THE FRONT BY MONDAY NIGHT WITH
A DRY FORECAST FAR SOUTH ON TUESDAY AS THE UPPER RIDGE MOVES ACROSS
THE OHIO VALLEY.
TEMPERATURES WILL BE CLIMBING EACH DAY AS THE WARM FRONT APPROACHES
AND IN ITS WAKE. BELOW NORMAL TEMPERATURES PER MODEL BLEND AND
CONSALL LOOK GOOD FOR SUNDAY WITH HIGHS ONLY IN THE MID 60S NORTH TO
THE LOWER 70S SOUTH. BY MONDAY WITH THE FRONT MOVING
THROUGH...SHOULD BE A STRONGER TEMPERATURE GRADIENT. HIGHS EXPECTED
TO WARM TO NEAR NORMAL IN THE UPPER 60S NORTHEAST TO THE UPPER 70S
SOUTHWEST. FINALLY...HIGHS WILL BE ABOVE NORMAL BY TUESDAY WITH
CENTRAL INDIANA IN THE WARM SECTOR. AFTERNOON HIGHS IN THE LOWER 80S
PER BLEND LOOK GOOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 212 PM EDT SAT MAY 25 2013
MODELS ARE CLOSE ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE USED
FOR MOST ITEMS.
UPPER RIDGE WILL BE IN CONTROL THROUGH MOST OF THE PERIOD...AND THIS
SHOULD KEEP A CAP ON CONVECTION. MODELS CONTINUE TO FLIP-FLOP ON
WHETHER RIDGE WILL BREAK DOWN ENOUGH FOR SOME CONVECTION ON FRIDAY.
RATHER THAN FLIP-FLOP WITH THIS FORECAST...WILL KEEP IT CONSISTENT
AND GO DRY THROUGH FRIDAY NIGHT. RIDGE LOOKS TO BREAK DOWN ENOUGH ON
SATURDAY FOR CHANCE POPS.
UPPER RIDGE WILL ALLOW WARM TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION /DISCUSSION FOR THE 25/2100Z TAF UPDATE/...
ISSUED AT 424 PM EDT SAT MAY 25 2013
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
VFR EXPECTED THROUGH THE PERIOD...WITH THE OUTSIDE CHANCE OF MVFR
IN SHOWERS.
AREA OF SHOWERS ACROSS ILLINOIS WILL CONTINUE TO WEAKEN AND SLIDE
SOUTHEAST AS IT MOVES INTO INDIANA THIS AFTERNOON. HOWEVER IT LOOKS
LIKE MOST SITES WILL SEE RAIN OUT OF IT. FOR NOW BELIEVE THAT
CONDITIONS IN RAIN WILL REMAIN VFR...BUT CANNOT RULE OUT BRIEF
PERIODS OF MVFR IF A HEAVIER SHOWER MAKES IT HERE.
AFTER THE INITIAL AREA OF RAIN EXITS EARLY THIS EVENING...CHANCES
FOR ADDITIONAL RAIN WILL CONTINUE. CONFIDENCE IN TIMING/LOCATION OF
RAIN IS TOO LOW OTHER THAN TO MENTION VCSH. THIS SCENARIO WILL
CONTINUE THROUGH SUNDAY. AGAIN MVFR CONDITIONS WOULD BE POSSIBLE IN
A HEAVIER SHOWER.
WINDS WILL REMAIN LIGHT AND VARIABLE INTO THIS EVENING...THEN
GRADUALLY BECOME SOUTHEAST. SPEEDS SHOULD REMAIN LESS THAN 10KT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM....50
AVIATION...50/TDUD
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