Area Forecast Discussion
Issued by NWS Indianapolis, IN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KIND 271940
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
240 PM EST SAT DEC 27 2014

.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 344 AM EST SAT DEC 27 2014

A COLD FRONT FROM EASTERN IOWA TO EAST TEXAS WILL MOVE EAST ACROSS
OUR REGION LATE TODAY AND EARLY TONIGHT.  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 SOME MODELS INDICATE A CHANCE OF MIXED
PRECIPITATION TOWARDS DAY 7 AS LOW PRESSURE SYSTEM MOVES INTO THE
LOWER MISSISSIPPI VALLEY.

&&

.NEAR TERM DISCUSSION /REST OF TODAY AND TONIGHT/...

ISSUED AT 959 AM EST SAT DEC 27 2014

1430Z UPDATE...MAIN CHANGES WERE TO POPS TO SHOW THE LULL IN
PRECIP EARLY TODAY AND THEN PICKING BACK UP THIS AFTERNOON. FIRST
WAVE OF RAIN MOVED THROUGH FAIRLY QUICKLY AND THE SECOND WILL
BEGIN SPREADING IN CENTRAL INDIANA AROUND 18-20Z THIS AFTERNOON AND
CONTINUE INTO TONIGHT. TEMPERATURES WILL BE SO WARM (HIGHS AROUND
50 DEGREES ON AVERAGE) THAT PRECIP TYPE WILL NOT BE A CONCERN FOR
TODAY...THAT POSSIBLY COMES LATER TONIGHT. NO OTHER MAJOR CHANGES
WERE MADE AT THIS TIME. PREVIOUS DISCUSSION FOLLOWS.

RADAR LOOPS INDICATE AN AREA OF LIGHT RAIN WAS SPREADING INTO
WESTERN PARTS OF OUR REGION AND SHOULD CONTINUE TO SPREAD EAST
DURING THE MORNING HOURS. SOME MODELS INDICATE THERE MAY BE A LULL
WITH THE RAIN TOWARDS MIDDAY AND THEN HAS IT INCREASING AGAIN AS THE
COLD FRONT MOVES IN LATER TODAY.  WILL GO WITH LIKELY POPS MOST
AREAS TODAY. CONCERNING TEMPERATURES CUT THEM A DEGREE OR TWO FROM A
MOS BLEND DUE TO PRECIP AND CLOUDS.

THE NAM ENDS THE RAIN TOO QUICKLY FROM THE NORTHWEST TONIGHT.  THEY
HAVE IT ALREADY ENDED AFTER 00Z THIS EVENING FOR INDY AND AREAS TO
THE NORTHWEST.  ALL THE OTHER MODELS ARE NOT THAT FAST AND WILL GO
ALONG WITH THE SLOWER ENDING OF PRECIPITATION.  THIS SLOWER ENDING
MAY ALLOW A BRIEF CHANGE OVER TO MIXED PRECIPITATION ACROSS OUR FAR
NORTHWEST BY MIDNIGHT AND SOUTH TO THE I70 REGION BY DAYBREAK SUNDAY.
FOR TONIGHT WENT WITH A MOS BLEND OVER NORTHWEST SECTIONS AND
SLIGHTLY ABOVE IN THE SOUTHEAST AS COLD ADVECTION WILL NOT BEGIN
THERE UNTIL LATE TONIGHT.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
ISSUED AT 344 AM EST SAT DEC 27 2014

SEVERAL MODELS KEEP SOME PRECIPITATION ACROSS OUR FAR SOUTHEAST
SUNDAY AS A WEATHER DISTURBANCE TRACKS ACROSS TENNESSEE TO THE MID
ATLANTIC STATES. WILL CONTINUE LOW CHANCE POPS THERE AT LEAST
THROUGH SUNDAY MORNING. LOW LEVEL THICKNESS INDICATE MIXED PRECIP
COULD OCCUR OVER EAST CENTRAL SECTIONS SUNDAY MORNING AND MOSTLY
RAIN FARTHER SOUTH.

DRY AND COOLER WEATHER WILL BE THE RULE THROUGH THE REST OF THE
SHORT TERM AS THE FIRST FRONTAL SYSTEM CONTINUES EAST.

MOST MODELS INDICATE HIGHS IN THE UPPER 30S SUNDAY AND PERHAPS A
DEGREE OR TWO WARMER MONDAY.  LOWS WILL BE IN THE MIDDLE TO UPPER
20S SUNDAY NIGHT AND LOWER OR MIDDLE 20S MONDAY NIGHT AS A DRY
SECONDARY COLD FRONT MOVES THROUGH.

&&

.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 27/1800Z TAF ISSUANCE/...

ISSUED AT 1200 PM EST SAT DEC 27 2014

DECENT CONFIDENCE THAT MVFR OR WORSE FLYING CONDITIONS ARE EXPECTED
TO BE OVER THE TERMINALS THE MAJORITY OF THIS AFTERNOON AND TONIGHT
BEFORE CONDITIONS IMPROVE TO VFR TOMORROW. MEANWHILE...RAIN WILL BE
INCREASING AT OR SHORTLY AFTER ISSUANCE TIME AND SHOULD END AFTER
04Z AT LAF...06Z AT IND AND HUF AND 08Z AT BMG.

A COLD FRONT SHOULD REACH LAF AND HUF AROUND 22Z AND IND AND BMG
AROUND 00Z. WINDS WILL SWITCH FROM SOUTHWEST TO WEST AND THEN
NORTHWEST AFTER THE FRONTAL PASSAGE. WIND SPEEDS WILL BE 9 TO 12
KNOTS THIS AFTERNOON AND EVENING AND LESS THAN 10 KNOTS TONIGHT.

&&

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

$$

SYNOPSIS...JH
NEAR TERM...SMF/JH
SHORT TERM...JH
LONG TERM....MK
AVIATION...MK

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS












USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.