Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 280836
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
335 AM EST SUN DEC 28 2014

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

&&

.SYNOPSIS...
ISSUED AT 335 AM EST SUN DEC 28 2014

A COLD FRONT ACROSS OHIO AND NORTHWEST KENTUCKY WILL CONTINUE MOVING
SOUTHEAST. THIS WILL BE FOLLOWED BY A RIDGE OF HIGH PRESSURE WHICH
WILL MOVE SUNDAY NIGHT AND MONDAY.  A DRY SECONDARY ARCTIC COLD
FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION AROUND TUESDAY. IN THE
LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL BRING DRY AND COLD
WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE AGAIN THIS FRIDAY
THROUGH NEXT SATURDAY AS MODELS SHOW A LOW PRESSURE SYSTEM MOVING
INTO THE LOWER MISSISSIPPI VALLEY FRIDAY AND ACROSS OUR REGION
SATURDAY.

&&

.NEAR TERM /TODAY AND TONIGHT/...
ISSUED AT 335 AM EST SUN DEC 28 2014

RADAR SHOWS PRECIPITATION WAS ENDING RAPIDLY FROM THE NORTHWEST AND
WILL PRETTY MUCH BE DONE BY FORECAST RELEASE TIME. SOME SITES ACROSS
OUR SOUTH AND SOUTHEAST MAY SEE A LITTLE DRIZZLE PRIOR TO 7AM.

MAIN ISSUES TODAY WILL BE HOW LONG CLOUDS WILL REMAIN AND
TEMPERATURES. SATELLITE SHOWS CLEARING LINE ACROSS NORTHWEST
ILLINOIS. ALTHOUGH THERE HAVE BEEN A FEW HOLES FARTHER SOUTHEAST.
THE RAP MODEL SOUNDINGS INDICATE MOSTLY CLOUDY SKIES THIS MORNING
AND DECREASING CLOUDS FROM MIDDAY ON.  EXPECT CLOUDS TO PERSIST OVER
SOUTHERN SECTIONS MOST OF TODAY AS THIS WILL BE LAST AREA TO CLEAR
OUT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE MIDDLE 30S NORTH TO
AROUND 40 FAR SOUTH WHICH IS SLIGHTLY BELOW A MOS BLEND ON
TEMPERATURES.

TONIGHT WILL BECOME MOSTLY CLEAR AS WEAK RIDGE OF HIGH PRESSURE
MOVES INTO OUR REGION.  WENT CLOSE TO A MOS BLEND ON TEMPERATURES
WITH LOWS IN THE LOWER 20S OVER NORTHERN SECTIONS AND THE MIDDLE AND
UPPER 20S SOUTH.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
ISSUED AT 335 AM EST SUN DEC 28 2014

MONDAY WILL BE SEASONABLY COOL WITH WEAK COLD ADVECTION AND HIGH
PRESSURE BUILDING IN FROM THE NORTHWEST.  LOW LEVEL THICKNESS
INDICATE HIGHS SHOULD BE FROM THE MIDDLE 30S OVER NORTHERN SECTIONS
TO AROUND 40 FAR SOUTH WITH MOSTLY SUNNY SKIES.

MODELS INDICATE A WEAK UPPER DISTURBANCE WILL TRACK ACROSS INDIANA
LATE MONDAY NIGHT AS A SECONDARY ARCTIC COLD FRONT MOVES OUR WAY.
THE NAM SHOWS SOME QPF ACROSS OUR NORTHWEST LATE MONDAY NIGHT WHILE
ALL OTHER MODELS ARE DRY.  ALL MODELS INDICATE SOME CLOUDS WITH THIS
FEATURE WILL MOVE INTO OUR NORTH LATE MONDAY NIGHT.  AS A COMPROMISE
WILL MENTION A CHANCE OF FLURRIES NORTHWEST SECTIONS LATE MONDAY
NIGHT. OTHERWISE...IT SHOULD REMAIN DRY.

THIS SYSTEM WILL QUICKLY MOVE ON TO THE EAST TUESDAY. 850 MB
TEMPERATURES WHICH WILL BE AROUND -5 TO -8 MONDAY WILL COOL TO -10
TO -13 CELSIUS TUESDAY. THUS SURFACE TEMPERATURES WILL BE A LITTLE
COLDER TUESDAY AND EVEN COLDER ON WEDNESDAY AS MORE ARCTIC AIR
PUSHES SOUTH INTO OUR REGION.  IN MOST CASES MOS SEEMS TO TO
HANDLING THIS OK AND ONLY MINOR TWEAKS MADE.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 240 PM EST SAT DEC 27 2014

MAIN FOCUS FOR THE EXTENDED PERIOD WILL BE POPS AND PRECIPITATION
TYPE STARTING FRIDAY. PRIOR TO THAT...TEMPERATURES WILL BE THE
BIGGEST ISSUE AS STRONG COLD WESTERN CANADIAN HIGH PRESSURE WILL
SETTLE ACROSS THE OHIO VALLEY TO END THE OLD YEAR AND START THE NEW
ONE.

DETERMINISTIC MODELS ARE IN DECENT AGREEMENT THAT AN UPPER LOW WILL
BE OVER NORTHEASTERN ARIZONA DURING THE EVENING OF THE FIRST DAY OF
2015. HOWEVER...THE MODELS THEN DIVERGE RAPIDLY WITH THE MUCH
QUICKER 12Z GFS BRINGING A STRONGER SURFACE SYSTEM BUT WEAK UPPER
WAVE OVER THE OHIO VALLEY FRIDAY NIGHT. MEANWHILE...THE 12Z ECMWF
HAS EVEN A WEAKER BUT MUCH SLOWER WAVE LIFT NORTHEAST TO SOUTHERN
ILLINOIS BY NEXT SATURDAY EVENING. THE EURO ALSO HAS THE MAIN
SURFACE LOW WELL SOUTHWEST OF THE 12Z GFS POSITION SATURDAY EVENING.
THE ECMWF HAS THE SURFACE LOW OVER EASTERN KENTUCKY...WHILE THE GFS
HAS IT OVER SOUTHERN QUEBEC. DESPITE ALL THESE DIFFERENCES...BOTH
MODELS START THE QPF ON FRIDAY WITH THE HEAVIEST PRECIPITATION ALONG
THE OHIO RIVER. MEANWHILE...THE EURO WAS HOLDING MORE QPF AROUND ON
SUNDAY THAN THE GFS. SO...STILL EXPECT THE PRECIPITATION TO SPREAD
NORTHEAST ACROSS THE AREA ON FRIDAY.  WITH CONFIDENCE IN TIMING
LOW...WILL ACCEPT THE REGIONAL BLEND THAT KEEPS DECENT POPS AROUND
NEXT SATURDAY AS HINTED AT BY THE EURO.

REGARDING PRECIPITATION TYPE...WILL NOT MAKE MANY CHANGES WITH THE
MODEL DIFFERENCES. CONFIDENCE NOT GOOD AS TO WHERE THE RAIN/SNOW
LINE WILL BE IN SPACE AND TIME. HOWEVER...NORTHEASTERN PARTS OF THE
FORECAST AREA WILL BE MORE LIKELY TO SEE FROZEN OR MIXED
PRECIPITATION THEN THE SOUTHWESTERN ONES ON FRIDAY BASED ON
THERMAL PROFILES FROM BUFKIT SOUNDINGS AS WELL AS PARTIAL
THICKNESSES. FRIDAY NIGHT AND SATURDAY...THE NORTHWESTERN COUNTIES
WOULD HAVE A HIGHER CHANCE OF MIXED OR FROZEN PRECIPITATION THAN THE
SOUTHEAST AS COLDER AIR MOVES IN FROM THE NORTHWEST IN THE WAKE OF
THE SURFACE SYSTEM. BUFKIT SOUNDINGS EVEN SUGGEST FREEZING RAIN OR
SLEET COULD POSSIBLY MIX IN AT TIMES FRIDAY NIGHT.

GENERALLY ACCEPTED THE REGIONAL BLEND TEMPERATURES. DO NOT FEEL
CONFIDENT ENOUGH TO MAKE CHANGES UNTIL THE MODELS HOPEFULLY COME
CLOSER TOGETHER IN SUBSEQUENT RUNS. AFTERNOON HIGHS IN THE 20S LOOK
GOOD ON NEW YEAR`S DAY WITH HIGHS MOSTLY IN THE 30S THEREAFTER.
MEANWHILE...NEW YEARS EVE NIGHT SHOULD BE THE COLDEST WITH OVERNIGHT
LOWS IN THE TEENS FOR THE FIRST SUNRISE OF THE YEAR. OVERNIGHT LOWS
WILL MOSTLY BE IN THE 20S AND 30S BY LATE WEEK.

&&

.AVIATION /DISCUSSION FOR THE 28/0900Z TAF UPDATE/...

ISSUED AT 324 AM EST SUN DEC 28 2014

UPDATE...
MVFR CONDITIONS ARE PREVAILING AT KIND AND WILL CONTINUE THROUGH
THE MORNING.

PREVIOUS DISCUSSION...
WINDS TO REMAIN BELOW 10 KNOTS THROUGH THE FORECAST.

RAIN HAS ENDED AT ALL TAF SITES EXCEPT KBMG BUT SHOULD ALSO END
THERE WITHIN THE HOUR OR AROUND 280700Z.

WITHIN COLD AND DRY AIR ADVECTING IN...VISIBILITY HAS IMPROVED TO 6+
MILES AND WILL REMAIN THAT WAY THROUGH THE FORECAST.

MULTIPLE CLOUD LAYERS HAVE BEEN OBSERVED ACROSS ILLINOIS BUT SEEM TO
BE SETTLING TOWARDS DECKS OF 1800-2200 FEET AND THESE SHOULD PREVAIL
THROUGH THE MORNING.  AS HIGH PRESSURE CONTINUES BUILDING IN AND
SUBSIDENCE BEGINS TO DRY THIS LOWER LAYER EXPECT BREAKS IN THE 2000
FOOT DECK AROUND 281800Z AND EVENTUAL CLEARING OF ALL CLOUDS BY
290000Z.

&&

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

&&

$$

SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM...MK
AVIATION...DT/TDUD

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