Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 210449
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1249 AM EDT THU AUG 21 2014

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 245 PM EDT WED AUG 20 2014

A RIDGE OF HIGH PRESSURE WILL STRENGTHEN OVER THE EASTERN THIRD OF
THE NATION THROUGH THE COURSE OF THE FORECAST PERIOD...BRINGING
THE HOTTEST WEATHER OF THE SUMMER. HIGHS WILL SOAR INTO THE LOW
90S BY THE END OF THE WEEK.  HOWEVER..WEAK WAVES WILL ROTATE
AROUND THAT RIDGE...KEEPING CHANCES FOR SHOWERS AND THUNDERSTORMS
OVER CENTRAL INDIANA THROUGH THE SHORT TERM PERIOD. A SURFACE WARM
FRONT WILL ALSO PROVIDE ADDITIONAL LIFT FOR CONVECTIVE DEVELOPMENT
THROUGH SATURDAY AS IT STALLS OVER NORTHERN INDIANA.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1007 PM EDT WED AUG 20 2014

CHANCES FOR STORMS WILL INCREASE ACROSS THE AREA AFTER 06Z AS A WARM
FRONT SLOWLY MOVES NORTH INTO THE AREA AND A LOW LEVEL JET RAMPS UP
TO THE WEST. SHORT RANGE MODELS CONTINUE TO INDICATE SOME POTENTIAL
FOR CONVECTIVE DEVELOPMENT ALONG THE FRONT AS WELL AS POTENTIAL FOR
SOME DEVELOPMENT IN SOUTHERN MINNESOTA/NORTHERN IOWA THAT COULD MOVE
INTO THE NORTHERN COUNTIES VERY LATE IN THE TONIGHT PERIOD INTO
THURSDAY MORNING. MADE ONLY SMALL ADJUSTMENTS TO GOING POPS TO KEEP
THE FORECAST DRY FOR ANOTHER HOUR OR TWO BEFORE HAVING A SLIGHT
CHANCE AND THEN INCREASING CHANCES AFTER 6Z. STILL A RELATIVELY
LARGE SPREAD IN POTENTIAL SOLUTIONS FOR THE OVERNIGHT AND THUS LOWER
THAN AVERAGE CONFIDENCE FOR THE OVERNIGHT.

TEMPS...CLOUD COVER DUE TO FRONTAL BOUNDARY OVER THE AREA WILL
KEEP TEMPS IN THE UPPER 60S/LOW 70S TONIGHT. THE NAM SEEMED TO BE
OVER DOING CLOUD COVER FOR MOST OF THE NEAR AND SHORT TERM
PERIODS. SO...LEANED TOWARD THE SLIGHTLY LOWER TEMPS OF THE GFS.

&&

.SHORT TERM /TOMORROW THROUGH SATURDAY/...
ISSUED AT 245 PM EDT WED AUG 20 2014

THE MAIN FOCUS OF THE SHORT TERM IS HOT TEMPERATURES AND SCATTERED
SHOWERS AND THUNDERSTORMS.

ENVIRONMENT WILL DESTABILIZE TOMORROW AS WARM ADVECTION SPREADS
OVER CENTRAL INDIANA BEHIND FRONT...TRIGGERING SHOWERS AND
THUNDERSTORMS. THE HIGHEST CHANCES WILL BE OVER THE NORTHERN
COUNTIES WHERE ADDITIONAL FORCING FROM THE FRONT WILL AID IN
CONVECTIVE DEVELOPMENT. AS A RESULT...CARRIED LIKELY POPS OVER
THAT AREA TOMORROW.

HIGH PRESSURE WILL CONTINUE TO STRENGTHEN OVER THE AREA FOR THE
REMAINDER OF SHORT TERM PERIOD...BUT WEAK WAVES IN THE FLOW WILL
DRIFT ALONG THE RIDGE...KEEPING CHANCES FOR SHOWERS AND
THUNDERSTORMS IN THE FORECAST THROUGH SATURDAY.

TEMPS...THE HIGHEST TEMPS OF THE SEASON WILL COMMENCE DURING THIS
FORECAST PERIOD WITH HIGHS REACHING INTO THE LOW TO MID 90S ON
FRIDAY AND SATURDAY. TRENDED ON THE WARMER SIDE OF GUIDANCE DUE TO
PERSISTENT SOUTHWEST FLOW.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 245 PM EDT WED AUG 20 2014

MODELS CONTINUE TO INDICATE SOME OF THE WARMEST WEATHER THIS SEASON
AS A STRONG UPPER RIDGE BUILDS OVER THE MIDDLE MISSISSIPPI VALLEY BY
THIS WEEKEND AND THEN SHIFTS TO THE OHIO VALLEY BY MONDAY AND THEN
WEAKENING SOME BY THE MIDDLE OF NEXT WEEK WHICH WILL ALLOW A COLD
FRONT TO MOVE SOUTH INTO OUR AREA.  MODELS INDICATE 850 MB
TEMPERATES OF +20 TO +22 CELSIUS AND 700 MB TEMPERATURES NEAR +10 MB
WHICH MAY LEAVE US PRETTY WELL CAPPED SUNDAY AND MONDAY.

GUIDANCE TEMPERATURES INDICATE HIGHS IN THE LOWER TO MIDDLE 90S. BUT
DUE TO THE WET GROUND CONDITIONS INITIALLY...WILL SHAVE 1-2 DEGREES
OFF HIGH TEMPERATURES. TEMPERATURES WILL BEGIN TO MODERATE A LITTLE
TUESDAY AND EVEN WEDNESDAY AS THE UPPER RIDGE BREAKS DOWN SOME.
THERE ARE SOME DIFFERENCES BETWEEN MODELS ON HOW MUCH OF THIS OCCURS.
HOWEVER WILL LEAN TOWARDS MODEL CONSENSUS FOR NOW.

&&

.AVIATION /DISCUSSION FOR THE 21/06Z TAFS/...
ISSUED AT 1249 AM EDT THU AUG 21 2014

MVFR VISIBILITIES POSSIBLE OVERNIGHT WITH FOG. RESTRICTIONS POSSIBLE
IN ANY CONVECTION THROUGH MIDDAY.

WEAK SURFACE RIDGING ACROSS CENTRAL INDIANA WITH JUST MID/HIGH LEVEL
CLOUDS DRIFTING THROUGH. COMPLEX OF STORMS OVER SOUTHERN ILLINOIS
NEAR THE FRONTAL BOUNDARY RIDING ALONG A THETA E RIDGE AND SHOULD
REMAIN SOUTH OF THE TERMINALS OVER THE NEXT FEW HOURS. DO ANTICIPATE
AN INCREASE IN SCATTERED CONVECTION AFTER 08Z AS THE BOUNDARY LIFTS
NORTH INTO THE FORECAST AREA AND THE NEXT UPPER LEVEL WAVE OVER THE
MISSOURI VALLEY SHIFTS EAST TOWARDS THE REGION. THE COMBINATION OF
THESE FEATURES ALONG WITH A LOW LEVEL JET NOSING INTO CENTRAL
INDIANA SHOULD SUPPORT EXPANDING CONVECTIVE DEVELOPMENT TO THE
NORTHWEST TOWARDS DAYBREAK...WITH STORMS MIGRATING INTO THE REGION
DURING THE MORNING. WITH SOME UNCERTAINTY IN EXTENT TO CONVECTIVE
COVERAGE AND SPECIFIC IMPACTS TO TERMINALS...WILL CARRY A BROAD
PERIOD OF PREVAILING SHOWERS WITH VCTS THROUGH MIDDAY.

UPPER RIDGING WILL ATTEMPT TO EXPAND ACROSS THE FORECAST AREA
THURSDAY AFTERNOON AS THE UPPER WAVE DEPARTS. POTENTIAL EXISTS FOR
RENEWED CONVECTIVE DEVELOPMENT LATE THURSDAY AFTERNOON AND EVENING
AS ANOTHER UPPER WAVE RIDES OVER THE RIDGE AND INTO THE LOWER GREAT
LAKES. WITH HIGH UNCERTAINTY...WILL KEEP CONDITIONS DRY AT THIS
TIME. SOUTHWEST WINDS TO AROUND 10KTS POSSIBLE TODAY.

&&

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

&&

$$

SYNOPSIS...TDUD
NEAR TERM...TDUD/CP
SHORT TERM...TDUD
LONG TERM...JH
AVIATION...RYAN

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