Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 050743
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
342 AM EDT TUE MAY 5 2015

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

&&

.SYNOPSIS...
ISSUED AT 228 PM EDT MON MAY 4 2015

A FRONTAL SYSTEM IS EXPECTED TO STALL OVER THE AREA TUESDAY...BEFORE
DISSIPATING BY WEDNESDAY. ANOTHER FRONTAL SYSTEM MAY AFFECT THE AREA
BY NEXT WEEKEND.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 957 PM EDT MON MAY 4 2015

CONVECTION CONTINUES ALONG TAIL OF UPPER VORTICITY CENTER ACROSS THE
NORTHEASTERN FORECAST AREA AND ALONG AN OUTFLOW BOUNDARY NOT TOO FAR
SOUTH OF I-70. ADDITIONAL CONVECTION IS DEVELOPING ACROSS ILLINOIS
ALONG AN OLD FRONT.

FOCUS FOR CONVECTION WILL LIKELY FOCUS ON THE NORTHERN FORECAST AREA
AS THE OLD FRONT LIFTS BACK NORTH TONIGHT. BASED ON LATEST TRENDS
REMOVED POPS FROM THE EXTREME SOUTH TONIGHT AND LOWERED THEM ACROSS
THE REST OF THE SOUTH THIRD.

ACROSS THE NORTH WENT SCATTERED CONVECTION WITH 30-50 POPS THIS
EVENING AS THE OLD FRONT/OUTFLOW BOUNDARY RETURNS NORTH. AS LARGER
AREA OF CONVECTION BRUSHES THE FAR NORTH OVERNIGHT CONTINUED WITH
ONGOING FORECAST OF LIKELY POPS THERE.

SINCE NORTHERN FORECAST AREA HAS BEEN WORKED OVER FEEL THAT ODDS OF
SEVERE STORMS ARE LOW. ELEVATED INSTABILITY COULD BRING SOME
ADDITIONAL SMALL HAIL THOUGH...SO WILL MENTION STRONG STORMS WITH
HAIL POSSIBLE IN HAZARDOUS WEATHER OUTLOOK.

ONLY MADE MINOR TWEAKS TO LOW TEMPERATURES BUT ADJUSTED HOURLY GRIDS
AS NEEDED BASED ON WHERE RAIN HAS FALLEN.

PORTION OF PREVIOUS FORECAST DISCUSSION FOLLOWS...
THINK THE BETTER CHANCES FOR MORE ORGANIZED SHOWER/THUNDERSTORM
ACTIVITY WILL BE LATE TONIGHT OVER THE NORTHERN ZONES AS THE LOW
LEVEL JET INCREASES. MODELS SUGGEST THE JET WON/T BE TOO
IMPRESSIVE...BUT IT APPEARS IT WILL BE IN THE RIGHT SPOT FOR GOOD
POTENTIAL FOR PRECIPITATION DEVELOPMENT. WILL GO WITH LIKELY POPS
OVER THE NORTH FOR MAINLY LATE TONIGHT...TAPERING TO CHANCE POPS
FARTHER SOUTH.

THE GFS MOS LOWS TONIGHT LOOK REASONABLE BASED ON LOW LEVEL
THICKNESSES...SO ONLY MINOR ADJUSTMENTS PLANNED.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 228 PM EDT MON MAY 4 2015

MODEL DATA SUGGEST FRONTAL ZONE OFF TO THE NORTH MAY SAG INTO THE
NORTHERN OR CENTRAL ZONES BY TUESDAY EVENING BEFORE WASHING OUT BY
WEDNESDAY UNDER BUILDING UPPER RIDGE. CONVECTIVE POTENTIAL NEAR THE
FRONT SHOULD DIMINISH WITH TIME AS HEIGHTS RISE. WILL KEEP SOME
CHANCE POPS GOING FOR TUESDAY AND TUESDAY EVENING...MAINLY OVER THE
CENTRAL AND NORTHERN ZONES.

SOME OF THE MODEL DATA CONTINUE TO SUGGEST A POTENTIAL FOR WIDELY
SCATTERED DIURNAL TYPE CONVECTION BOTH WEDNESDAY AND THURSDAY.
APPEARS CONVECTIVE TEMPERATURES SHOULD EASILY BE REACHED BOTH
DAYS...BUT LAPSE RATES TAIL OFF BY THEN AS MID LEVELS WARM. WILL
CONTINUE WITH A DRY FORECAST AFTER TUESDAY NIGHT FOR NOW.

DON/T HAVE TOO MUCH OF A PROBLEM WITH THE GFS TEMPERATURES GUIDANCE
IN THE LATER PERIODS BASED ON PROGGED LOW LEVEL THICKNESSES.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 342 AM EDT TUE MAY 5 2015

WARM AND STORMY EXTENDED IS IN THE CARDS AS UPPER RIDGE...CURRENTLY
OVER THE SOUTHERN STATES AND OHIO VALLEY SHIFTS TO THE EASTERN COAST
AND ATLANTIC...AND A STRONG UPPER SOUTHERN CALIFORNIA LOW LIFTS
NORTHEAST LEAVING CENTRAL INDIANA IN SOUTHWEST FLOW ALOFT. THE UPPER
LOW WILL SPIN UP A SURFACE LOW. THE 00Z ECMWF AND GEM AND THE ECMWF
ENSEMBLE MEANS ARE FURTHER NORTHEAST WITH THIS FEATURE BY 00Z MONDAY
AS THEY TAKE IT TO WESTERN IOWA. THE GFS AND ITS ENSEMBLE MEANS HAD
IT WELL SOUTHWEST AND STRONGER OVER NORTHWESTERN KANSAS AT THAT
TIME. FAVOR A ECMWF...ECEM AND GEM BLEND WHICH KICKY SLIDES THE LOW
EAST ACROSS THE GREAT LAKES AND AN ASSOCIATED COLD FRONT SOUTHEAST
ACROSS CENTRAL INDIANA MONDAY NIGHT.

AT ANY RATE...ALL MODELS BRING SOUTHERLY FLOW OFF THE GULF TO THE
OHIO VALLEY THROUGHOUT THE EXTENDED AHEAD OF THE PREVIOUSLY
MENTIONED LOW PRESSURE SYSTEM. THIS WILL CONTINUE TO BRING
WARM...MOIST AND UNSTABLE AIR TO CENTRAL INDIANA. VARIOUS UPPER
WAVES IN THE SOUTHWEST FLOW AND LATER THE APPROACHING FRONTAL
SYSTEM...SUGGEST REGIONAL BLEND LOOKS GOOD WITH THUNDERSTORM CHANCES
EACH PERIOD.

REGIONAL BLEND TEMPERATURES LOOK GOOD WITH AFTERNOON HIGHS IN THE
UPPER 70S TO MID 80S. OVERNIGHT LOWS SHOULD ONLY DROP TO THE
60S.

&&

.AVIATION /DISCUSSION FOR 050600Z TAF ISSUANCE/...
ISSUED AT 1230 AM EDT MON MAY 4 2015

FOG MAY PRODUCE LIFR CONDITIONS AT KLAF NEXT FEW HOURS AND SHOWERS
AND THUNDERSTORMS COULD AFFECT KLAF LATE TONIGHT. OTHERWISE...MOSTLY
VFR EXCEPT NEAR THUNDERSHOWERS NORTHERN AREAS LATE TONIGHT AND
TUESDAY.

A STATIONARY WILL REMAIN NORTHERN INDIANA THROUGH TUESDAY AS A UPPER
RIDGE BUILDS ACROSS THE OHIO VALLEY AND MIDDLE MISSISSIPPI VALLEYS.
AN AREA OF THUNDERSTORMS OVER ILLINOIS MAY AFFECT KLAF IN A FEW
HOURS AND THIS SHOULD CLEAR OUT LIFR FOG THERE. AFTER MID MORNING
TUESDAY MODELS INDICATE SCATTERED THUNDERSTORMS OVER NORTHERN
INDIANA...WHILE CENTRAL AND SOUTHERN SECTIONS SHOULD REMAIN VFR AND
DRY.  EXPECT MOSTLY SCATTERED CLOUDS AROUND 5 THOUSAND WITH BROKEN
HIGH CLOUDS ONCE THUNDERSTORMS MOVE OUT OF THE AREA.

WINDS WILL BE LIGHT OVERNIGHT AND SOUTHWEST UP TO 12 KNOTS TUESDAY
AND LIGHT SOUTHERLY TUESDAY NIGHT.

&&

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

&&

$$

SYNOPSIS...JAS
NEAR TERM...JAS/50
SHORT TERM...JAS
LONG TERM....MK
AVIATION...JH

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