Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 192022
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
422 PM EDT FRI SEP 19 2014

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

&&

.SYNOPSIS...
ISSUED AT 218 PM EDT FRI SEP 19 2014

HIGH PRESSURE OVER THE NORTHEAST WILL SLOWLY DEPART TONIGHT AND
SATURDAY...PROVIDING A BIT MORE DRY WEATHER FOR CENTRAL INDIANA
ALONG WITH PLEASANT TEMPERATURES.

A QUICK MOVING COLD FRONT IS THEN EXPECTED TO SWEEP THROUGH THE
REGION LATE SATURDAY BEFORE DEPARTING ON SUNDAY MORNING. THIS WILL
BRING CHANCES FOR LIGHT RAIN SHOWERS OR PERHAPS A THUNDERSTORM TO
CENTRAL INDIANA.

COOL NORTH WINDS ARE THEN EXPECTED TO RETURN ON SUNDAY AFTERNOON
AS THE FRONT DEPARTS AND ANOTHER AREA OF CANADIAN HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES AND OHIO VALLEY...RESULTING IN DRY
WEATHER THROUGH THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /TONIGHT/...

ISSUED AT 218 PM EDT FRI SEP 19 2014

SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS LARGE HIGH PRESSURE
CENTERED OVER NEW ENGLAND...EXTENDING IT/S INFLUENCE FAR WEST TO
MIDDLE MISSISSIPPI VALLEY AND THE SOUTHERN PLAINS. LOW PRESSURE WAS
FOUND OVER THE DAKOTAS WITH A COLD FRONT STRETCHING SOUTHWEST TOWARD
CENTRAL COLORADO. LIGHT EAST WINDS WERE IN PLACE ACROSS CENTRAL
INDIANA AND DEW POINTS REMAINED IN THE PLEASANT MID AND UPPER 40S.
SATELLITE IMAGES SHOW CLEAR SKIES ACROSS THE STATE AND RADAR WAS
QUIET. WATER VAPOR IMAGERY SHOWS RIDGING IN PLACE...SLOWLY
FLATTENING ACROSS THE CENTRAL UNITED STATES ALONG WITH A LARGE
AREA OF SUBSIDENCE ACROSS MISSISSIPPI/OHIO AND TENNESSEE RIVER
VALLEYS.

MAIN FORECAST CHALLENGE TONIGHT WILL BE TEMPS.

UPPER RIDGING ACROSS THE CENTRAL PLAINS IS EXPECTED TO CONTINUE TO
FLATTEN OUT OVERNIGHT...AND THIS WILL BRING A STOP TO THE
SUBSIDENCE ONGOING ACROSS THE REGION. THIS ALSO SHOULD RESULT IN
THE STREAMING OF SOME HIGH AND MID CLOUD ACROSS THE UPPER MIDWEST
TO BEGIN TO REACH THE OHIO VALLEY LATE TONIGHT.
NONETHELESS...SKIES SHOULD REMAIN MOSTLY CLEAR THROUGH THE NIGHT
AND LIGHT SOUTH WINDS WILL ONCE AGAIN LEAD TO A GOOD RADIATIONAL
COOLING SET-UP. GIVEN OUR WEAK WARM AIR ADVECTION THAT IS EXPECTED
CONTINUE THROUGH THE NIGHT ALONG WITH RISING THICKNESSES...WILL
CONTINUE TO TREND HIGHS WARMER THAN PERSISTENCE...AND MODEL
GUIDANCE HAS A GOOD HANDLE ON THAT.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...

ISSUED AT 218 PM EDT FRI SEP 19 2014

MODELS REMAIN IN PRETTY GOOD AGREEMENT DURING THIS PERIOD AND
ALSO REMAIN RATHER CONSISTENT FROM RUN TO RUN...BOOSTING
CONFIDENCE IN THE FORECAST.

DRY WEATHER IS EXPECTED TO CONTINUE ON SATURDAY AS THE SURFACE HIGH
TO THE EAST CONTINUES TO DEPART AND THE RIDGE TO THE WEST ALSO
BEGINS TO BREAK DOWN. FORECAST SOUNDINGS CONTINUE TO SUGGEST
UNATTAINABLE CONVECTIVE TEMPERATURES AMID A DRY COLUMN ON
SATURDAY. HOWEVER SOME HIGH CLOUD CANNOT RULED OUT AS SUBSIDENCE
WANES ACROSS THE AREA. THUS WILL AIM FOR PARTLY CLOUDY ON SATURDAY
AS FOR TEMPS THE WARM AIR ADVECTION CONTINUES ON SOUTHERLY WINDS.
THUS WILL ONCE AGAIN AIM FOR HIGHS WARMER THAN
PERSISTENCE. A BLEND OF MAV MOS MET SHOULD WORK NICELY.

GFS AND NAM CONTINUE TO SUGGEST A THINK BAND OF SHOWERS AND
MOISTURE WORKING ACROSS THE STATE ON SATURDAY NIGHT AND EARLY
SUNDAY. A SHARP SURFACE TROUGH IS SEEN IN THE LOWER
LEVELS...PROVIDING CONVERGENCE. Q VECTORS AGREE SHOWING LOWER
LEVEL CONVERGENCE ALSO. 310 ISENTROPIC SURFACE IS NOT AS
FAVORABLE...STILL NOT SHOWING MUCH IN THE WAY OF LIFT...HOWEVER IT
CONTINUES TO SHOW AND SURGE OF HIGHER SPECIFIC
HUMIDITIES...GREATER THAN 6 G/KG...PUSHING ACROSS INDIANA LATE
SATURDAY AND EARLY SUNDAY. ALOFT...GFS SHOW A DEEPER WAVE TROUGH
DIVING SOUTH OUR OF THE UPPER MIDWEST TOWARD THE OHIO VALLEY ON
SATURDAY NIGHT AND SUNDAY...PROVIDING ADDITIONAL FORCING. FORECAST
SOUNDINGS FAIL TO DEEP SATURATION FOR AN EXTENDED PERIOD OF
TIME...BUT DO SHOW A SIGNIFICANT INCREASE IN AVAILABLE MOISTURE AS
PWATS RISE TO OVER 1 INCH. THUS WITH MANY INGREDIENTS AVAILABLE
FOR RAIN...BUT NOT ALL OF THEM...CONFIDENCE IN A LIGHT RAIN EVENT
CONTINUES TO GROW. WILL ONCE AGAIN RAISE POPS FOR TO THE LIKELY OR
HIGH CHANCE CATEGORY FOR SATURDAY NIGHT. AS FOR TEMPS WILL TREND
WARMER THAN GUIDANCE HERE GIVEN THE EXPECTED CLOUDS AND RAIN.

AS FOR SUNDAY POPS WILL STICK CLOSE TO MAVMOS POPS AS TIMING
OF DEPARTURE OF THE THIN LINE OF SHOWERS REMAINS IN QUESTION.
HOWEVER THIS MUCH IS CLEAR...BY AFTERNOON GFS AND NAM SUGGEST
MUCH DRYER AIR ARRIVING IN CENTRAL INDIANA AS FORECAST SOUNDINGS
DRY OUT. THUS WILL TREND FORECAST TO DRY BY NOON ON SUNDAY. AS FOR
TEMPS WILL USE A BLEND OR TREND COOLER THAN MAVMOS AS COLD AIR
ADVECTION IS EXPECTED IN THE WAKE OF THE FRONT.

GFS AND NAM THEN SUGGEST ANOTHER VERY LARGE AND BROAD AREA OF COOL
HIGH PRESSURE ARRIVING FOR SUNDAY NIGHT AND MONDAY. FORECAST
SOUNDINGS DRY OUT DRAMATICALLY THROUGH MONDAY. MODEL SUGGEST THE
DEEP TROUGH ALOFT OVER THE GREAT LAKES DIGGING ACROSS INDIANA ON
MONDAY...HOWEVER THE STRONG DRY SURFACE HIGH SHOULD STILL PREVAIL
IN A DRY FORECAST. FORECAST SOUNDINGS CONTINUE TO SUGGEST
UNATTAINABLE CONVECTIVE TEMPS. WILL TREND TEMPS COOLER THAN MAVMOS
AMID A DRY FORECAST ON SUNDAY NIGHT AND MONDAY.

&&

.LONG TERM /MONDAY NIGHT THROUGH NEXT FRIDAY/...

ENSEMBLES INDICATE UPPER TROUGHING OVER THE EASTERN PORTIONS OF THE
COUNTRY AT THE BEGINNING OF THE PERIOD WILL LIFT OFF TO THE
NORTHEAST. IN ITS WAKE...A LARGE UPPER RIDGE WILL BECOME ESTABLISHED
OVER THE AREA BY THE MIDDLE TO LATE PARTS OF NEXT WEEK.

ENSEMBLES INDICATE VERY LITTLE THREAT FOR PRECIPITATION THROUGH THE
PERIOD AS UPPER RIDGE BUILDS. WILL CONTINUE WITH A DRY EXTENDED.

&&

.AVIATION /DISCUSSION FOR THE 192100Z TAF UPDATE/...
ISSUED AT 422 PM EDT FRI SEP 19 2014

KIND TAF ONLY NEEDED MINOR TWEAK TO WIND DIRECTION. FORECAST OK.

PREVIOUS DISCUSSION FOLLOWS...
NO SIGNIFICANT CLOUD COVER AND UNRESTRICTED VISIBILITY EXPECTED AT
THE TAF SITES THROUGH 200600Z.

SURFACE WINDS 110-130 AT 9-12 KTS THIS AFTERNOON EXPECTED TO
DIMINISH TO 6 KTS OR LESS AFTER SUNSET.


&&

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

$$

SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...JAS
AVIATION...JAS/50

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