Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 201923
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
323 PM EDT WED MAY 20 2015

.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.

&&

.SYNOPSIS...
ISSUED AT 319 PM EDT WED MAY 20 2015

AN UPPER LEVEL DISTURBANCE WILL TRACK THROUGH THE REGION THIS
EVENING WITH LIGHT RAIN AND UNSEASONABLY COOL CONDITIONS. COOL AND
MAINLY CLOUDY WEATHER WILL PERSIST THURSDAY...WITH PROGRESSIVELY
WARMER WEATHER BEGINNING FRIDAY AND CONTINUING INTO THE HOLIDAY
WEEKEND. MORE UNSETTLED WEATHER WILL RETURN SUNDAY INTO EARLY NEXT
WEEK AS WELL WITH SCATTERED THUNDERSTORMS POSSIBLE.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 323 PM EDT WED MAY 20 2015

SEEMS THE CALENDAR WENT BACKWARDS SEVERAL WEEKS WITH THE WEATHER
BEING EXPERIENCED IN THE HOOSIER STATE TODAY. CLOUDS HAVE STEADILY
THICKENED AND NOW LIGHT RAIN SHOWERS HAVE DEVELOPED WITH MORE
WIDESPREAD PRECIP COMING FOR THE LATE AFTERNOON AND EVENING.

WITH RAW NORTHEAST WINDS...TEMPS HAVE STRUGGLED TO THE LOWER 50S AS
OF 19Z. 51 REMAINS THE HIGH AT INDY AS OF 19Z...WITH GROWING
CONFIDENCE THAT THE HIGH WILL NOT REACH 55. WOULD MAKE TODAY ONLY
THE 3RD TIME IN RECORDED HISTORY THAT THE HIGH HAS NOT REACHED 55 ON
MAY 20. IMPRESSIVE.

LOW PRESSURE CURRENTLY NEAR MEMPHIS TENNESSEE THIS AFTERNOON WITH AN
INVERTED SURFACE TROUGH EXTENDING N/NW INTO THE LOWER OHIO VALLEY.
THE LOW WILL TRACK EAST THROUGH THE TENNESSEE VALLEY THIS EVENING
WITH THE TROUGH SWINGING ACROSS THE REGION. A QUICK BURST OF
ISENTROPIC LIFT WILL MOVE ACROSS THE AREA OVER THE NEXT 6-8 HOURS
AND COMBINED WITH SOME MOISTENING OF THE BOUNDARY LAYER...WILL SEE
WIDESPREAD LIGHT SHOWERS CURRENTLY OVER ILLINOIS EXPAND INTO THE
FORECAST AREA INTO THE EVENING. PRESENCE OF DRY NORTHEAST FLOW AT
THE SURFACE WILL KEEP PRECIP AMOUNTS LIGHT...ON THE ORDER OF A TENTH
OF AN INCH OR LESS FOR MANY. DESPITE THAT...EXPECTED COVERAGE
WARRANTS LIKELY POPS FOR THE LATE AFTERNOON AND EVENING.

HI-RES GUIDANCE CONSISTENT IN SHIFTING MOST OF THE PRECIP EAST OF
THE FORECAST AREA AFTER MIDNIGHT AS THE INVERTED TROUGH DEPARTS AND
ISENTROPIC DOWNGLIDE DEVELOPS. MODEL SOUNDINGS AND RH PROGS MAINTAIN
AN ABUNDANCE OF MOISTURE BELOW 10KFT...WITH MAINLY CLOUDY SKIES
PERSISTING THROUGH DAYBREAK THURSDAY.

TEMPS...TRENDED CLOSER TO LAMP GUIDANCE FOR LOWS OVERNIGHT AS ITS
DONE REASONABLY WELL CAPTURING THE MUCH COOLER TEMPS TODAY. EXPECT
LOWS INTO THE LOW AND MID 40S FOR MOST OF THE REGION.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 323 PM EDT WED MAY 20 2015

FORECAST CHALLENGES FOCUS ON CLOUDS FOR THURSDAY AND TEMPS
THROUGHOUT THE PERIOD AS CONDITIONS GRADUALLY RECOVER TO A MORE
TYPICAL LATE MAY PATTERN.

SUBTLE IMPROVEMENTS FOR WEATHER THURSDAY BUT IT WILL STAY COOL AND
MAINLY CLOUDY AS THE REGION REMAINS UNDER THE INFLUENCE OF A BROAD
UPPER TROUGH. THE LOWER LEVELS WILL STEADILY DRY OUT AS HIGH
PRESSURE BEGINS TO WORK IN DURING THE COURSE OF THE DAY. HOWEVER...
MODEL SOUNDING AND RH PROGS MAINTAIN A MODEST AMOUNT OF MOISTURE IN
THE 5-10KFT WITH MORE SUBSTANTIAL CLEARING NOT OCCURRING UNTIL LATE
DAY AND POSSIBLY THURSDAY EVENING ONCE A MID LEVEL SHORT WAVE TRACKS
THROUGH THE AREA. PLENTY OF MID LEVEL CLOUDS AND STRATUS IN THE
VICINITY OF THIS FEATURE THIS AFTERNOON OVER SOUTHWEST MINNESOTA/
SOUTHEAST SOUTH DAKOTA.

SKIES WILL BECOME MOSTLY CLEAR THURSDAY NIGHT AS DEEPER SUBSIDENCE
ARRIVES WITH THE HIGH SETTLING OVER THE LOWER OHIO VALLEY. YET
ANOTHER WAVE ROTATING AROUND THE PARENT UPPER TROUGH WILL DIVE
THROUGH LOWER MICHIGAN AND INTO NORTHERN OHIO EARLY FRIDAY. THIS
FEATURE WILL HAVE LITTLE IMPACT ON THE FORECAST AREA...OTHER THAN
BRUSHING NORTHEAST COUNTIES WITH A SUBTLE INCREASE IN CLOUDS AND
CAUSING A RETURN TO NORTHERLY WINDS AND A BRIEF SHOT OF COLD
ADVECTION.

THE HIGH WILL THEN TAKE OVER FOR THE REMAINDER OF THE SHORT TERM
WITH SURFACE FLOW GRADUALLY VEER TO SOUTHEAST AS THE HIGH DRIFTS
INTO THE MID ATLANTIC REGION ON SATURDAY AND RIDGING ALOFT
ESTABLISHES. WHILE THERE WILL DEFINITELY BE MUCH MORE SUNSHINE FOR
FRIDAY AND SATURDAY...DO EXPECT SOME DIURNAL CU FRIDAY AFTERNOON
WITH CONVECTIVE TEMPS IN THE UPPER 60S. MID AND HIGH CLOUDS WILL
THEN BEGIN TO INCREASE IN RETURN FLOW SATURDAY.

TEMPS...UNDERCUT MOS FOR THURSDAY AS CLOUDS WILL KEEP TEMPS LOWER.
GENERALLY GOING LOWER 60S FOR THE ENTIRE FORECAST AREA...AND THIS
MAY EVEN BE GENEROUS CONSIDERING 850MB TEMPS ARE COOLER THAN TODAY.
THE ROAD TO RECOVERY WILL START FRIDAY WITH HIGHS RETURNING INTO THE
70S FOR BOTH FRIDAY AND SATURDAY. MAVMOS LOOKED REASONABLE FOR HIGHS
BOTH DAYS. LOWS WILL SLOWLY RETURN INTO THE UPPER 40S/LOWER 50S BY
SATURDAY MORNING.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 235 PM EDT WED MAY 20 2015

THE INITIALIZATION FROM THE REGIONAL MODEL WILL BE ACCEPTED.
CONFIDENCE IN THIS FORECAST IS MODERATE.

THERE IS GOOD MODEL AGREEMENT ON LARGE SCALE FEATURES...ESPECIALLY
THE THERMAL FIELDS...THROUGH THE PERIOD.

THERE ARE SOME DIFFERENCES ON SMALL SCALE FEATURES...WHICH WILL HAVE
A MAJOR IMPACT IN TIMING AND PLACEMENT OF CONVECTION...WHICH IN TURN
WILL HAVE A SIGNIFICANT EFFECT ON SENSIBLE WEATHER.

THESE ISSUES BECOME EVIDENT AS EARLY AS SATURDAY NIGHT AND SUNDAY.
BOTH THE GFS AND EUROPEAN MODELS BOTH GRADUALLY DEVELOP
PRECIPITATION FROM WEST TO EAST. HOWEVER THE TIMING IS JUST
DIFFERENT ENOUGH TO MAKE A MAJOR DIFFERENCE IN WHAT PEOPLE WILL
EXPERIENCE AT ANY ONE TIME.

&&

.AVIATION /DISCUSSION FOR 201818Z TAF ISSUANCE/...
ISSUED AT 1255 PM EDT WED MAY 20 2015

A WEAK TROUGH OF LOW PRESSURE WILL APPROACH THE AREA TODAY...CROSS
IT TONIGHT...AND THEN MOVE OFF TO THE EAST THURSDAY.

VFR CONDITIONS ARE EXPECTED INTO EVENING. DURING THE NIGHT THE
PASSAGE OF THE TROUGH SHOULD PRODUCE WIDESPREAD MVFR CEILINGS AND
AREAS OF IFR CEILINGS. CEILINGS WILL RECOVER TO LOW VFR LEVELS LATE
TONIGHT OR THURSDAY MORNING. VISIBILITY SHOULD STAY AT 6 MILES OR
MORE THROUGH THE FORECAST PERIOD.

THE EASTWARD PROGRESS OF THE TROUGH WILL CAUSE SCATTERED SHOWERS
UNTIL LATE TONIGHT.  RAIN IS LIKELY AT ONE TIME OR ANOTHER IN MOST
LOCATIONS. HOWEVER TIMING OF RAIN IS VERY UNCERTAIN AND DURATION AT
ANY ONE POINT WILL BE SHORT. VCSH IS MORE REPRESENTATIVE OF WHAT
WILL OCCUR RATHER THAN EXPLICIT RAIN FORECASTS.

WINDS SHOULD MAINTAIN SPEEDS OF NEAR 10 KNOTS AS THEY BACK FROM EAST
TO NORTHWEST DURING THE FORECAST PERIOD.

&&

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

&&

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JK
AVIATION...JK

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