Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 260411
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1111 PM EST THU DEC 25 2014

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 229 PM EST THU DEC 25 2014

HIGH PRESSURE WILL MOVE ACROSS THE AREA THROUGH FRIDAY. A FRONTAL
SYSTEM IS EXPECTED TO AFFECT THE AREA OVER THE WEEKEND. IN THE WAKE
OF THIS FRONTAL PASSAGE...HIGH PRESSURE IS EXPECTED TO BUILD INTO
THE AREA FOR MOST OF NEXT WEEK.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1024 PM EST THU DEC 25 2014

HOURLY NUMERICAL GUIDANCE...HRRR...AND DEWPOINT TRENDS SUGGEST MIN
TEMPS WERE A BIT TOO LOW. RAISED THESE ANYWHERE FROM 1-3 DEGREES
DEPENDING ON THE SPOT. REMAINDER OF FORECAST IN GOOD SHAPE ASIDE
FROM TWEAKS TO SKY GRIDS. PREVIOUS DISCUSSION FOLLOWS.

ISSUED AT 229 PM EST THU DEC 25 2014

CLEARING LINE CONTINUES TO PROGRESS ACROSS THE WESTERN AND
SOUTHWESTERN ZONES. BASED ON EXTRAPOLATION AND SHORT TERM
MODELS...MOST AREAS SHOULD CLEAR OUT BY 260000Z OR SO.
OTHERWISE...EXPECTING JUST SOME HIGH LEVEL CLOUDS OVERNIGHT ALONG
WITH DRY CONDITIONS AS SURFACE HIGH PRESSURE PASSES OFF TO THE EAST.

TEMPERATURES PROBABLY WON/T FALL TOO MUCH TONIGHT GIVEN DECENT WARM
ADVECTION. THE GFS MOS LOWS LOOK OK.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 229 PM EST THU DEC 25 2014

MODEL DATA INDICATE PROGRESSIVE UPPER FLOW ACROSS THE COUNTRY DURING
THIS PERIOD...WITH MEAN TROUGHING OVER THE ROCKIES AND UPPER RIDGING
OVER THE SOUTHEAST PARTS OF THE COUNTRY.

MAIN WEATHER MAKER DURING THIS PERIOD WILL BE A UPPER SYSTEM THAT
SHEARS OUT FROM THE MEAN ROCKIES TROUGH ACROSS THE LOCAL AREA BY THE
WEEKEND. MODELS IN PRETTY GOOD AGREEMENT IN BRINGING SUFFICIENT
LIFT/DEEP MOISTURE FOR THE POTENTIAL FOR PRECIPITATION TO THE
WESTERN ZONES STARTING LATE FRIDAY NIGHT. WILL KEEP POPS GOING AT
THAT TIME. HIGHEST POPS WITH THIS SYSTEM APPEAR TO BE SATURDAY INTO
SATURDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA. OPERATIONAL
MODELS SUGGEST THE PRECIPITATION THREAT WILL BE ABOUT DONE BY SUNDAY
MORNING...ALTHOUGH THE ENSEMBLES SUGGEST THIS MAY TOO FAST. WILL
KEEP SOME CHANCE POPS GOING OVER THE SOUTHERN ZONES INTO SUNDAY
MORNING.

THICKNESSES SUGGEST THIS WILL MOSTLY BE A RAIN EVENT...ALTHOUGH
ENOUGH COLD AIR MAY SNEAK IN LATE SATURDAY NIGHT/SUNDAY MORNING FOR
THE POTENTIAL FOR MIXED PRECIPITATION. LITTLE OR NO ACCUMULATIONS
EXPECTED AT THIS TIME AS QPF LOOKS LIGHT AND TEMPERATURES WILL BE
MARGINAL.

THE GFS MOS TEMPERATURES LOOK REASONABLE FOR THE MOST PART BASED ON
LOW LEVEL THICKNESS PROGS. DECIDED TO NUDGE UP THE GUIDANCE LOWS
SATURDAY NIGHT A CATEGORY TO ACCOUNT FOR THE POSSIBILITY OF A SLOWER
FRONTAL PASSAGE.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 233 PM EST THU DEC 25 2014

MAIN FOCUS FOR THE EXTENDED WILL BE ON TEMPERATURES AS DETERMINISTIC
MODELS AND ENSEMBLES FAVOR DRY WEATHER.

EXTENDED MODELS CONTINUE TO SUGGEST THAT THE EXTENDED WILL BE MOSTLY
OR ALL DRY AS STRONG HIGH PRESSURE ACROSS WESTERN CANADA SUNDAY
NIGHT WILL SHIFT TO THE PLAINS BY TUESDAY OF NEXT WEEK. THIS WILL
BRING COLDER AIR TO CENTRAL INDIANA. HOWEVER...THE ARCTIC AIR LOOKS
TO BE SHUNTED WELL NORTH OF THE FORECAST AREA. SO...REGIONAL BLEND
TEMPERATURES LOOK GOOD INCORPORATING A BLEND OF THE WARMER EUROPEAN
ENSEMBLE MOS AND THE DETERMINISTIC MOS. SHOULD SEE HIGHS MOSTLY IN
THE 30S AND LOWS IN THE 20S.

&&

.AVIATION /DISCUSSION FOR THE 260600Z TAFS/...

ISSUED AT 1053 PM EST THU DEC 25 2014

VFR CONDITIONS ARE EXPECTED THIS TAF PERIOD.

INDIANA LOOKS TO REMAIN BETWEEN HIGH PRESSURE OVER THE
SOUTHEASTERN STATES AND DEVELOPING LOW PRESSURE OVER THE CENTRAL
PLAINS. SOUTHERLY FLOW AND WARM AIR ADVECTION WILL CONTINUE ACROSS
THE TAF SITES THROUGH FRIDAY NIGHT. IR IMAGES SHOW A STEADY STREAM
OF HIGH CIRRUS CLOUDS EXPECTED TO ADVECT NORTHEAST INTO
INDIANA FROM THE SOUTHWEST.

AGAIN...TIME HEIGHT SECTIONS AND SOUNDINGS SHOW LOWER LEVEL MOISTURE
LINGERING ACROSS THE AREA...HOWEVER IN REALITY...NONE OF THAT IS
TO BE FOUND. THUS WILL TREND TOWARD THE VFR HIGH CLOUDS AS SEEN BY SATELLITE.

GFS AND NAM SUGGEST THE RETURN OF LOWER VFR CIGS ON SATURDAY NIGHT
AS LOWER LEVEL MOISTURE CONTINUES TO SURGE NORTH AHEAD OF THE
TROUGH DEVELOPING IN THE PLAINS STATES. THUS HAVE TRENDED CIGS
LOWER...ALBEIT STILL VFR THROUGH FRIDAY NIGHT.

&&

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

$$

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

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