Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 300649
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
248 AM EDT SAT AUG 30 2014

.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 351 PM EDT FRI AUG 29 2014

THE PRESENCE OF A FRONTAL BOUNDARY INTERACTING WITH A WARM HUMID
AIRMASS AND SEVERAL UPPER LEVEL WAVES WILL BRING MULTIPLE
OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS OVER THE HOLIDAY WEEKEND
AND CONTINUING THROUGH MUCH OF NEXT WEEK.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 1006 PM EDT FRI AUG 29 2014

UPDATED POPS BASED ON RADAR TRENDS AND MADE SOME MINOR TWEAKS TO
MIN TEMPS. IN GENERAL...FORECAST IN OK SHAPE. PREVIOUS DISCUSSION
FOLLOWS.

ISSUED AT 351 PM EDT FRI AUG 29 2014

AFTER ABOUT A 36 HOUR BREAK FROM THE MUGGY CONDITIONS...THE HUMIDITY
IS RETURNING IN EARNEST AS A WARM FRONT SHIFTS NORTH ACROSS THE
FORECAST AREA. AS OF 19Z...APPEARS THE BOUNDARY EXTENDING SOUTHEAST
FROM NORTHEAST ILLINOIS ACROSS THE NORTHERN PART OF THE FORECAST
AREA. DESPITE THE CLOUDS EARLIER TODAY...TEMPS HAVE RECOVERED INTO
THE 80S ACROSS MUCH OF THE FORECAST AREA.

ISOLATED CONVECTION HAS DEVELOPED ALONG THE STRONGER INSTABILITY
AXIS ACROSS WESTERN INDIANA. AS CONVECTIVE TEMPS ARE REACHED IN PEAK
HEATING OVER THE NEXT FEW HOURS...EXPECT SOME INCREASE IN
COVERAGE...ESPECIALLY ACROSS THE WESTERN HALF OF THE FORECAST AREA.
WILL CONTINUE WITH CHANCE POPS INTO THE EVENING HOURS...WITH HIGHEST
POPS NORTHWEST OF THE INDY METRO. WITH LITTLE FORCING ALOFT OR BL
SHEAR AVAILABLE...STORMS SHOULD LARGELY REMAIN DISORGANIZED AND
MULTICELLULAR WITH TORRENTIAL RAINFALL AND LIGHTNING BEING THE
PRIMARY IMPACTS. A FEW STRONGER STORMS WILL HAVE THE POTENTIAL TO
PRODUCE LOCALLY GUSTY WINDS AS WELL.

SLIGHTLY DRIER AIR EXPECTED TO ADVECT INTO THE REGION TONIGHT AS THE
WARM FRONT LIFTS INTO THE NORTHERN GREAT LAKES. CANNOT ENTIRELY RULE
OUT AN ISOLATED STORM OVERNIGHT...BUT MOST AREAS SHOULD REMAIN DRY
UNTIL CLOSER TO DAYBREAK AS CONVECTION ASSOCIATED WITH AN UPPER WAVE
APPROACHES FROM THE WEST.

TEMPS...LEANED CLOSER TO THE WARMER METMOS GUIDANCE WITH THE RETURN
OF THE MOIST HUMID AIRMASS. SHOULD SEE LOWS RANGE FROM THE MID 60S
TO LOWER 70S ACROSS THE REGION.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 351 PM EDT FRI AUG 29 2014

FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AS AN UNSETTLED PATTERN
CONTINUES THROUGH THE HOLIDAY WEEKEND.

TWO SEPARATE SYSTEMS WILL IMPACT WEEKEND WEATHER ACROSS CENTRAL
INDIANA...BRINGING PERIODIC THREATS FOR THUNDERSTORMS. WHILE THE
WEEKEND WILL NOT BE A WASHOUT...THE PRESENCE OF A BOUNDARY LAID OUT
ACROSS THE REGION...A RICH FEED OF TROPICAL MOISTURE FROM THE GULF
OF MEXICO FUELING A MOIST UNSTABLE AIRMASS AND THE AFOREMENTIONED
TWO SYSTEMS WARRANTS A PERSISTENT CONVECTIVE THREAT INTO EARLY NEXT
WEEK.

AN UPPER WAVE LOCATED OVER THE UPPER MISSISSIPPI VALLEY SATURDAY
MORNING WILL BE THE FIRST SYSTEM TO IMPACT THE AREA AS IT DRIFTS
INTO THE GREAT LAKES BY EARLY SUNDAY WITH LOW PRESSURE AT THE
SURFACE ACCOMPANYING. WHILE STORMS ARE LIKELY TO BE AROUND AS EARLY
AS SATURDAY MORNING...EXPECT CONVECTIVE COVERAGE TO MAXIMIZE DURING
THE AFTERNOON WITH THE ADDITION OF DIURNAL HEATING AND LOW LEVEL
MOISTURE FUELING AVAILABLE INSTABILITY. THESE STORMS WILL CONTINUE
SATURDAY NIGHT AS THE WAVE PASSES TO THE NORTH THROUGH THE GREAT
LAKES. BESIDES MODEST BOUNDARY LAYER FLOW...REGION WILL RESIDE IN
THE RIGHT REAR OF AN UPPER JETLET PASSING THROUGH LOWER MICHIGAN
WHICH MAY ENHANCE CONVECTIVE COVERAGE INTO THE NIGHT. WILL MAINTAIN
LIKELY POPS FROM THE AFTERNOON THROUGH SATURDAY NIGHT. HEAVY
RAINFALL AND DANGEROUS LIGHTNING WILL AGAIN BE MAIN CONCERNS WITH
STORMS REMAINING LARGELY SUBSEVERE.

WITH THE LOW MOVING EAST INTO QUEBEC...THE BETTER THREATS FOR RAIN
AND THUNDERSTORMS WILL SHIFT INTO THE SOUTHERN FORECAST AREA ON
SUNDAY AS THE DEEPER PLUME OF TROPICAL MOISTURE PLUME SLIPS SOUTH
INTO THE OHIO RIVER VALLEY. FURTHER NORTH...SUBTLE RIDGING ALOFT AND
WEAK SURFACE HIGH PRESSURE IN THE WAKE OF THE LOW SHOULD LEAD TO
LESS CONVECTIVE COVERAGE AS THE DAY PROGRESSES. EXPECT MAINLY DRY
CONDITIONS FROM LATE AFTERNOON INTO THE OVERNIGHT SUNDAY AS THE WEAK
HIGH OVERSPREADS THE ENTIRE AREA SUNDAY NIGHT.

SECOND SYSTEM TO IMPACT THE REGION MAKES ITS ARRIVAL MONDAY AS A
SHARP UPPER WAVE AND ASSOCIATED FRONTAL BOUNDARY TRACK INTO THE
GREAT LAKES. SOUTHERLY FLOW AHEAD OF THE FRONT ALONG WITH A 30KT LOW
LEVEL JET WILL BRING A RENEWED SURGE OF LOW LEVEL MOISTURE INTO THE
REGION BY AFTERNOON. POTENTIAL FOR MORE ORGANIZED STORMS AND
POSSIBLY A BETTER THREAT FOR SEVERE STORMS AS FORCING ALOFT...SHEAR
AND STORM RELATIVE HELICITIES ARE MORE PLENTIFUL WITH THE UPPER
LEVEL FEATURE. WILL ONCE AGAIN BRING IN HIGHER POPS FOR MONDAY.

TEMPS...HIGHS SATURDAY AND SUNDAY WILL BE HIGHLY DEPENDENT ON CLOUD
COVER AND PRECIP. PREFER THE WARMER MAV FOR SATURDAY WITH DEEPER
MOISTURE HOLDING OFF UNTIL THE AFTERNOON AND THE COOLER MET ON
SUNDAY. CONSALL WORKED WELL FOR LOWS THROUGHOUT THE PERIOD RANGING
FROM THE MID 60S TO LOWER 70S.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 248 AM EDT SAT AUG 30 2014

THUNDERSTORM CHANCES ALONG WITH TEMPERATURES WILL BE FOCUS FOR THE
LONG TERM. ENSEMBLE BLEND CONTINUES TO LOOK BETTER THAN THE
DETERMINISTIC MODELS WHICH ARE TENDING TO CHANGE A BIT RUN TO RUN
REGARDING THE SPECIFICS OF THE UPCOMING SYNOPTIC PATTERN. TRENDS
CONTINUE THAT AN UPPER TROUGH WILL MOVE ACROSS THE LOWER GREAT LAKES
ON TUESDAY IN THE FAST FLOW ALOFT AS A COLD FRONT DROPS SOUTHEAST
ACROSS CENTRAL INDIANA. THIS SHOULD BE ENOUGH TO PRODUCE SCATTERED
TO WIDESPREAD THUNDERSTORMS ON TUESDAY AND LINGERING INTO TUESDAY
NIGHT. AFTER THAT...UPPER RIDGE WILL BUILD ACROSS THE AREA FROM THE
SOUTH. AS A RESULT REGIONAL BLEND SUGGESTS ONLY SMALL POPS THROUGH
THURSDAY NIGHT. MEANWHILE...AFTER A BRIEF BREAK IN TEMPERATURES IN
THE WAKE OF THE COLD FRONT ON WEDNESDAY...LATE WEEK TEMPERATURES
WILL BE ABOVE NORMAL WITH AFTERNOON HIGHS IN THE LOWER 90S POSSIBLE
ACROSS SOUTH CENTRAL INDIANA ON FRIDAY PER THE REGIONAL BLEND.
FINALLY...ANOTHER FRONT WILL BE IN THE AREA NEXT WEEKEND WHICH
SHOULD BRING BETTER CHANCES OF THUNDERSTORMS IN ONCE AGAIN.

&&

.AVIATION /DISCUSSION FOR THE 30/0600Z TAF ISSUANCE/...
ISSUED AT 1200 AM EDT SAT AUG 30 2014

MOSTLY VFR UNTIL LATE SATURDAY NIGHT. HOWEVER SCATTERED SHOWERS AND
THUNDERSTORMS MAY BRIEFLY LOWER FLIGHT CONDITIONS ON SATURDAY.

HIGH PRESSURE OVER THE WESTERN ATLANTIC AND LOW PRESSURE MOVING INTO
THE GREAT LAKES WILL KEEP US UNDER A LIGHT TO MODERATE SOUTHERLY
FLOW. AN UPPER DISTURBANCE WILL BRING A FEW SHOWERS INTO WESTERN
SECTIONS TOWARDS DAYBREAK AND SCATTERED SHOWERS AND THUNDERSTORMS
ALL AREAS ON SATURDAY. THESE SHOWERS AND THUNDERSTORMS WILL BE MOST
NUMEROUS BY EARLY AFTERNOON WITH DAYTIME HEATING.

THE SHOWERS AND THUNDERSTORMS WILL DIMINISH SATURDAY NIGHT WITH LOSS
OF DAYTIME HEATING AND SLIGHT RIDGING ALOFT.  MODEL SOUNDINGS
INDICATE MVFR CEILINGS MAY DEVELOP LATE SATURDAY NIGHT.

WINDS WILL BE SOUTH LESS THAN 8 KNOTS OVERNIGHT AND SOUTH UP TO 15
KNOTS SATURDAY AND SOUTHWEST 8 KNOTS OR LESS SATURDAY NIGHT.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN/NIELD
SHORT TERM...RYAN
LONG TERM...MK
AVIATION...JH

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