Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 300135
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
934 PM EDT FRI APR 29 2016

.UPDATE...

THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 306 PM EDT SAT APR 30 2016

AN UPPER LOW...OVER SOUTHERN COLORADO AND NORTHERN NEW MEXICO...WILL
GRADUALLY HEAD NORTHEAST TOWARD THE OHIO VALLEY THIS WEEKEND AS A
WARM FRONT LIFTS NORTH INTO SOUTHERN INDIANA LATE SATURDAY. THESE
FEATURES WILL INTERACT WITH INCREASING MOISTURE AND RESULT IN
SHOWERS OVERSPREADING CENTRAL INDIANA BY EARLY SATURDAY. IT WILL DRY
OUT EARLY NEXT WEEK BEFORE A PAIR OF COLD FRONTS BRING MORE SHOWERS
TO THE AREA BY WEDNESDAY.

WITH WIDESPREAD CLOUD COVER AND SHOWERS...TEMPERATURES WILL BE BELOW
NORMAL THROUGH EARLY NEXT WEEK. AFTER THAT...LOOK FOR NORMAL TO
SLIGHTLY BELOW TEMPERATURES THROUGH LATE NEXT WEEK.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 934 PM EDT FRI APR 29 2016

SHORT TERM MODEL GUIDANCE AND THIS EVENING/S UPPER AIR SUGGEST
GENERALLY WEAK WARM ADVECTION/LIFT ACROSS THE LOCAL AREA THROUGH
MOST OF THE NIGHT...WITH MORE ORGANIZED LIFT MOVING INTO THE SOUTHWEST
ZONES TOWARDS DAYBREAK. BASED ON THIS...WILL BACK OFF ON THE TIMING AND
SPACIAL EXTEND OF THE LIKELY POPS TO ALIGN BETTER WITH THE ARRIVAL OF
THE BETTER LIFT.

PREVIOUS DISCUSSION FOLLOWS.

THE MAIN FOCUS TONIGHT WILL BE ON POPS AS MODELS HAVE DIFFERENCES ON
HOW FAR NORTHEASTWARD WIDESPREAD SHOWERS WILL GET.

MODELS AGREE THAT SOUTHWESTERN UPPER LOW WILL MOVE NORTHEAST TO
NORTHWESTERN KANSAS AND SOUTHWESTERN NEBRASKA BY 12Z SATURDAY. UPPER
WINDS WILL THEN BACK IN RESPONSE ACROSS THE MISSISSIPPI VALLEY AND
RESULT IN SOUTHERN STATES STATIONARY FRONT RETURNING NORTH TO NEAR A
SIKESTON MISSOURI TO CHATTANOOGA LINE BY 12Z. MODELS ALL SHOWING
ISENTROPIC LIFT AT THE 305K LEVEL NORTH OF THE FRONT ALONG WITH
UPPER IMPULSES EJECTING NORTHEAST AROUND THE BASE OF THE UPPER LOW
AND INTO THE OHIO VALLEY. CONDENSATION PRESSURE DEFICITS ALONG WITH
LATEST RADAR TRENDS AND RAPID REFRESH ALL FAVOR THE FASTER 12Z
DETERMINISTIC ECMWF...NAM AND GEM OVER THE SLOWER 12Z GFS. THIS
WOULD BRING WIDESPREAD SHOWERS TO ALL BUT THE FAR NORTHEASTERN PARTS
OF THE FORECAST BY DAYBREAK.

INSTABILITY PROGS FAVOR LEAVING THUNDER OUT TONIGHT.

WITH SHOWERS OVERSPREADING THE AREA...FAVOR TEMPERATURES AT OR
SLIGHTLY BELOW SIMILAR 12Z MOS.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 306 PM EDT FRI APR 29 2016

THE MAIN FOCUS FOR THE SHORT TERM WILL BE ON RAINFALL TOMORROW.
HOWEVER...THERE IS ALSO A POTENTIAL FOR THUNDERSTORMS TOMORROW
AFTERNOON AND EVENING...ESPECIALLY ACROSS THE SOUTHERN HALF WHERE
SOME COULD BE SEVERE.

MODELS ALL AGREE THAT A WARM FRONT WILL BE LIFTING INTO SOUTHWESTERN
INDIANA LATE SATURDAY. THE FRONT ALONG WITH SEVERAL SHORTWAVES
EJECTING NORTHEAST IN THE SOUTHWEST UPPER FLOW AROUND THE BASE OF
THE CENTRAL PLAINS UPPER LOW WILL INTERACT WITH DEEP MOISTURE AND
MODESTLY INCREASING AFTERNOON INSTABILITY. THIS WILL RESULT IN
SHOWERS OVERSPREADING ALL OF CENTRAL INDIANA FROM SOUTHWEST TO
NORTHEAST ON SATURDAY. THIS PERIOD SHOULD BE THE WETTEST PERIOD AS
INDICATED BY THE 12 HOUR QPF ENDING 00Z SUNDAY. MODEL BLEND HAS NEAR
THREE QUARTERS OF AN INCH ON SATURDAY WITH STORM TOTAL RAINFALL OVER
AN INCH FROM TONIGHT THROUGH SUNDAY.

THUNDERSTORMS ARE POSSIBLE...ESPECIALLY DURING THE AFTERNOON
TOMORROW AND SOUTH OF INTERSTATE 74. THE STORM PREDICTION CENTER HAS
PLACED MUCH OF THIS AREA IN A MARGINAL RISK OF SEVERE WEATHER FOR
DAY2. THERE IS EVEN A SLIVER OF A SLIGHT RISK ACROSS EXTREME
SOUTHWESTERN KNOX COUNTY. THIS SEEMS REASONABLE WITH MODEST
INSTABILITY BUT GOOD SHEAR AS A 40-50 KNOT LOW LEVEL JET WILL MOVE
ACROSS THE AREA DURING THE AFTERNOON AND EVENING AND AN 85 KNOT 250
MILLIBAR JET STREAK WILL MOVE TO THE WABASH VALLEY.

SHOULD SEE THE SHOWER COVERAGE DECREASE OVERNIGHT SATURDAY NIGHT AS
THE LOW LEVEL JET AND DEEPER MOISTURE SHIFT NORTHEAST INTO THE
EASTERN GREAT LAKES AND THE ALLEGHENY PLATEAU.

THE SHOWERS AND THUNDERSTORMS WILL BE PICKING UP ONCE AGAIN ON
SUNDAY AS THE SLOW MOVING UPPER LOW IS ABSORBED INTO AN EASTERN
CANADA TROUGH...THE FRONT CAMPS OUT OVER SOUTH CENTRAL INDIANA AND
INSTABILITY INCREASES DUE TO MID LEVEL DRYING AND STEEP MID LEVEL
LAPSE RATES. THE SHOWERS SHOULD BE ENDING OVERNIGHT SUNDAY NIGHT
FROM NORTHWEST TO SOUTHEAST AS THE FRONTAL SYSTEM AND UPPER TROUGH
MOVE EAST AND CANADIAN HIGH PRESSURE SETTLES SOUTHEAST.

STAYED CLOSE TO OR SLIGHTLY BELOW THE BELOW NORMAL MODEL BLEND
TEMPERATURES SATURDAY AND SUNDAY DUE TO EXTENSIVE CLOUD COVER AND
SHOWERS. AFTERNOON HIGHS SHOULD REMAIN BELOW NORMAL ON MONDAY
DESPITE SOME SUNSHINE AS THE AREA WILL BE IN NORTHEAST LOW LEVEL
FLOW AROUND THE HIGH. FINALLY...WILL GO WITH NEAR OR ABOVE BLEND FOR
OVERNIGHT LOWS DUE TO THICK CLOUD COVER.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 239 PM EDT FRI APR 29 2016

THE LONG TERM STARTS OUT DRY WITH AN UPPER WAVE SLIDING WEST AND
THEN SOUTH OF THE AREA. ON WEDNESDAY AN UPPER WAVE WILL MOVE
THROUGH INDIANA BRINGING CHANCES FOR SHOWERS WITH IT. AS IT MOVES
OUT WEDNESDAY NIGHT COULD SEE SOME LIGHT SHOWERS HANG AROUND IN
THE WRAPAROUND OF THE LOW. AT THIS TIME DOESN/T APPEAR TO BE
MUCH IF ANY INSTABILITY THROUGH THE LONG TERM SO WILL NOT INCLUDE
ANY THUNDER...AND ASIDE FROM WEDNESDAY ANY FORCING APPEARS MINIMAL
SO NOTHING GREATER THAN SLIGHT CHANCES INCLUDED. TEMPERATURES LOOK
NEAR NORMAL IN THE MID TO UPPER 60S FOR HIGHS AND 40S TO LOW 50S
FOR LOWS.

&&

.AVIATION /DISCUSSION FOR THE 30/00Z TAFS/...
ISSUED AT 714 PM EDT FRI APR 29 2016

VFR CONDITIONS HAVE RETURNED TO ALL BUT LAF EARLY THIS EVENING...AND
LAF WILL BECOME VFR IN THE NEXT FEW HOURS. EXPECT VFR CONDITIONS
MUCH OF THE NIGHT...WITH CONDITIONS DETERIORATING IN SHOWERS AND
THUNDERSTORMS SATURDAY MORNING.

LOW PRESSURE WILL ALLOW SHOWERS AND PERHAPS THUNDERSTORMS TO
OVERSPREAD THE AREA SATURDAY MORNING. EXPECT DETERIORATING
CONDITIONS AFTER AROUND DAYBREAK TIME FRAME SATURDAY...WITH IFR
CONDITIONS LIKELY FROM MIDDAY ONWARD. EMBEDDED THUNDERSTORMS WILL BE
A THREAT...AND WILL INCLUDE VCTS AT ALL SITES.

WINDS WILL BE A BIT VARIABLE AT FIRST...BECOMING MORE NORTHEASTERLY
AND THEN EAST/SOUTHEASTERLY WITH TIME. WINDS SATURDAY WILL LIKELY BE
SUSTAINED AROUND 10-13KT WITH GUSTS TO AROUND 20KT.

&&

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

&&

$$

SYNOPSIS...MK
NEAR TERM...MK/JAS
SHORT TERM...MK
LONG TERM...CP
AVIATION...NIELD



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