Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 270758
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
258 AM EST FRI FEB 27 2015

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

&&

.SYNOPSIS...
ISSUED AT 340 PM EST THU FEB 26 2015

A FEW FLURRIES MAY LINGER INTO THIS EVENING. OTHERWISE...PARTIAL
CLEARING WILL BE THE RULE LATE TONIGHT AND FRIDAY AS ARCTIC HIGH
PRESSURE OVER THE NORTHERN PLAINS BUILDS OUR WAY.  THIS HIGH
PRESSURE WILL MOVE ON TO SOUTHERN NEW ENGLAND BY SATURDAY AND A
STRONG UPPER DISTURBANCE WILL MOVE OUR WAY LATE SATURDAY NIGHT AND
SUNDAY BRINGING ACCUMULATING SNOWS TO NORTH AND CENTRAL SECTIONS AND
MIXED PRECIPITATION TO OUR SOUTH.

THERE WILL BE A BREAK MONDAY AND THEN ANOTHER SYSTEM WILL BRING
RAIN TO OUR SYSTEM BY TUESDAY.  THIS PRECIPITATION MAY BEGIN AS
FREEZING RAIN MONDAY NIGHT AND MIXED PRECIPITATION IS POSSIBLE OVER
NORTHERN SECTIONS TUESDAY NIGHT AND WEDNESDAY.  FINALLY THERE IS A
SLIGHT CHANCE OF LIGHT SNOW WEDNESDAY NIGHT AND THURSDAY AS COLDER
AIR MOVES BACK INTO OUR REGION.

&&

.NEAR TERM /REST OF TONIGHT/...

ISSUED AT 950 PM EST THU FEB 26 2015

UPDATE...
CURRENT RADAR MOSAIC IS STILL SHOWING LIGHT RETURNS ACROSS CENTRAL
AND SOUTHERN PORTIONS OF CENTRAL INDIANA. AS A RESULT...WILL CARRY
MENTION OF SNOW SHOWERS THROUGH FRI 04Z...AND FLURRIES THROUGH FRI
06Z. ANY ACCUMULATIONS SHOULD BE MINOR. CURRENT TEMPS ARE RANGING
FROM THE SINGLE DIGITS AND LOW TEENS OVER NORTHERN AND CENTRAL
COUNTIES...TO UPPER TEENS OVER THE SOUTHERN COUNTIES. THESE WILL
PLUMMET FURTHER AS CLOUDS CLEAR OUT AND SNOW ENDS AFTER MIDNIGHT.
SO...WILL KEEP WIND CHILL ADVISORY IN EFFECT ACROSS THE NORTHERN
COUNTIES. UPDATED GRIDS HAVE BEEN SENT.

PREVIOUS DISCUSSION...
EXPECT ONLY A FEW FLURRIES
THIS EVENING AND THEN DECREASING CLOUDS LATER TONIGHT AS DRIER AIR
SPREADS IN.

THE MAIN ISSUE TONIGHT WILL BE VERY COLD TEMPERATURES ALONG WITH
LIGHT WINDS.  THERE SHOULD BE PRETTY GOOD RADIATIONAL COOLING LATE
TONIGHT AND CUT TEMPERATURES A LITTLE.  I WAS A LITTLE MORE
CONSERVATIVE WITH MY TEMPERATURES HOWEVER...AS SKIES MAY NOT CLEAR
COMPLETELY.  NERVELESS IT LOOKS LIKE NORTHERN SECTIONS MAY BE COLD
ENOUGH LATE TONIGHT AND FRIDAY MORNING FOR LOWEST WINDS CHILLS NEAR
15 BELOW.  THUS WILL ISSUE A WIND CHILL ADVISORY FROM 4 AM TO 11 AM
FOR THE NORTHERN THIRD TO HALF OF OUR REGION.

FRIDAY WILL BE MOSTLY SUNNY AS HIGH PRESSURE MOVES EAST ACROSS OUR
REGION. EVEN THOUGH AIR MASS IS QUITE COLD...WENT SLIGHTLY ABOVE MOS
TEMPERATURES GIVEN A DECENT AMOUNT OF SUNSHINE FRIDAY.

LOWS TONIGHT WILL RANGE FROM 4 BELOW NORTHEAST TO 6 ABOVE SOUTH AND
HIGHS FRIDAY WILL RANGE FROM THE LOWER TEENS NORTH TO NEAR 20 SOUTH.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 340 PM EST THU FEB 26 2015

HIGH PRESSURE WILL CONTINUE TO BRING COLD BUT QUIET WEATHER FRIDAY
NIGHT AND SATURDAY AS IT MOVES TO SOUTHERN NEW ENGLAND. THEN ALL
MODELS SPREAD PRECIPITATION ACROSS OUR REGION LATER SATURDAY NIGHT
THROUGH SUNDAY EVENING AS A UPPER DISTURBANCE MOVES ACROSS OUR
REGION.  LOW LEVEL THICKNESS INDICATE ALL SNOW OVER NORTHERN
SECTIONS...WHILE SOUTHERN SECTIONS MAY START OUT AS SNOW AND THEN
CHANGE TO RAIN SUNDAY.  THERE MAY ALSO BE A PERIOD OF FREEZING RAIN
DURING THIS CHANGE OVER.   WENT CLOSE TO HPC SNOW AMOUNTS WHICH
INDICATED 5 TO 7 INCHES FAR NORTH TO MAYBE AN INCH OR TWO SOUTH.
THE NAM INDICATED PRECIPITATION SHOULD BE OVER BY SUNDAY
EVENING...WHILE THE GFS WAS ALMOST 12 HOURS LATER IN ENDING
PRECIPITATION.  WENT WITH A BLEND WITH PRECIPITATION ENDING MOST
AREAS BY LATE SUNDAY EVENING.

CONCERNING TEMPERATURES...WENT WITH A MOS BLEND MOST AREAS.
TEMPERATURES MAY RISE A LITTLE LATE SATURDAY NIGHT AND ON SUNDAY CUT
A FEW DEGREES ACROSS NORTHERN SECTIONS.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 258 AM EST FRI FEB 27 2015

ACTIVE PATTERN CONTINUES THROUGH THE FIRST HALF OF NEXT WEEK AS
PIECES OF ENERGY ALOFT EJECT OUT OF THE TROUGH OVER THE WESTERN U S
FOLLOWED BY THE TROUGH AXIS ITSELF MOVING EAST INTO THE REGION BY
THE END OF THE PERIOD. HIGH CONFIDENCE IN A SIGNIFICANT WEATHER
IMPACT FOR CENTRAL INDIANA AND THE OHIO VALLEY MONDAY NIGHT THROUGH
WEDNESDAY.

STRONG HIGH PRESSURE ARRIVES IN THE WAKE OF THE LATE WEEKEND SYSTEM
FOR MONDAY...AND SHOULD SERVE TO GIVE THE REGION A BREATHER BETWEEN
WEATHER SYSTEMS ON THE ORDER OF 18 TO 24 HOURS. SURFACE WAVE SET
TO SPIN UP OVER THE CENTRAL ROCKIES MONDAY NIGHT AS ENERGY EJECTS
OUT FROM THE PARENT TROUGH. THIS FEATURE WILL SWING E/NE AND TRACK
QUICKLY INTO THE REGION BY TUESDAY EVENING AND BRING WITH IT A
PLETHORA OF MESSY PROBLEMS FOR CENTRAL INDIANA. RIDGING DEVELOPING
DOWNSTREAM OF THE TROUGH SUPPORTS MORE AMPLIFIED FLOW WITH THE
SYSTEM TRACKING THROUGH OR NORTH OF THE FORECAST AREA. OP GFS
SHOWING ITS USUAL PROGRESSIVE BIAS IN THE MID RANGE IN BRINGING
PRECIP IN TOO QUICKLY...ESPECIALLY CONSIDERING THE STRENGTH OF THE
DEPARTING HIGH. LIKE THE LOOK OF THE ECMWF/GGEM WHICH DELAYS MOST
PRECIP UNTIL AFTER MIDNIGHT MONDAY NIGHT.

WARM ADVECTION WILL ALREADY BE ONGOING WHEN PRECIP STARTS...AND EXPECT
PRECIP TYPE ISSUES FROM THE GET GO WITH A GROWING LIKELIHOOD THAT
FREEZING RAIN IS THE PREDOMINANT PRECIP TYPE INTO TUESDAY MORNING.
THE REFRESHED SNOWPACK COURTESY OF THE WEEKEND STORM WILL BE A
SIGNIFICANT FACTOR IN DURATION OF FROZEN PRECIP AS THE NEAR
SURFACE/GROUND TEMPS WILL LAG THE LOW LEVEL TEMP RISES. MODEL
THERMAL PROFILES ARE ALREADY SUGGESTIVE THAT IT MAY TAKE UNTIL
MIDDAY TUESDAY IN SOME PORTIONS OF THE REGION TO WARM SUFFICIENTLY
FOR ALL RAIN. IF THE IMPACT OF THE SNOWCOVER IS UNDERMINED BY THE
MODELS WHATSOEVER...THE ICING POTENTIAL COULD BE EVEN MORE
SIGNIFICANT. DO NOT EXPECT TO HAVE A GOOD HANDLE ON THIS UNTIL LATER
IN THE WEEKEND.

WHILE THE ICING THREAT IS A GROWING ISSUE...AN EXTENDED PERIOD OF
HEAVY RAIN OVER A FROZEN GROUND AND SNOW COVER POSES EVEN GREATER
CONCERNS. COPIOUS AMOUNTS OF MOISTURE WILL BE DRAWN NORTH INTO THE
REGION AHEAD OF THE APPROACHING SURFACE WAVE TUESDAY AND TUESDAY
NIGHT. PRECIP WATER VALUES ARE PARTICULARLY ALARMING...MAXING OUT
BETWEEN 1.25 AND 1.50 INCHES TUESDAY EVENING. THESE LEVELS WOULD
PLACE THE REGION NEAR AND ABOVE THE 99TH PERCENTILE FOR
CLIMATOLOGICAL PRECIP WATER VALUES IN MARCH. POTENTIAL FOR
CONVECTIVE ELEMENTS TO THE PRECIP AS WELL AND MAY NEED TO ADD AN
ISOLATED THUNDER MENTION INTO THE FORECAST FOR TUESDAY
AFTERNOON/NIGHT. 1-2 INCHES OF RAINFALL CERTAINLY LOOK PLAUSIBLE AND
WITH MOST OF THIS BEING CONVERTED TO PURE RUNOFF WITH THE FROZEN
GROUND...FLOODING CONCERNS ARE VALID. FRONTAL BOUNDARY SHOULD
FINALLY MOVE EAST WEDNESDAY WITH PRECIP ENDING LATE DAY...LIKELY AS
A RAIN/SNOW MIX. MUCH COLDER AIR WILL THEN RETURN FOR THE END OF THE
WEEK.

STILL PLENTY TO HASH OUT AND THE WEEKEND WINTER STORM WILL HAVE SOME
SAY IN HOW THIS ALL TRANSPIRES. AS STATED ABOVE THOUGH...CONFIDENCE
IS HIGH IN SIGNIFICANT WEATHER IMPACTS FOR CENTRAL INDIANA MONDAY
NIGHT THROUGH WEDNESDAY...WITH ICING...HEAVY RAIN AND FLOODING ALL
POTENTIAL CONCERNS. ENCOURAGE HOOSIERS TO STAY ABREAST OF THE
FORECAST OVER THE NEXT FEW DAYS.

&&

.AVIATION /DISCUSSION FOR THE 270600Z TAF ISSUANCE/...

ISSUED AT 1119 PM EST THU FEB 26 2015

MOSTLY VFR EXPECTED. *POSSIBLY* SOME VERY BRIEF MVFR IN SOME OF
THE WIDELY SCATTERED FLURRIES BUT NOT ENOUGH IN COVERAGE TO
MENTION IN TAFS AT THIS TIME. ALSO THE LAKE EFFECT DOES NOT
APPEAR IT WILL REACH KLAF EARLY THIS MORNING.

OTHERWISE EXPECT GENERAL VFR CONDITIONS FOR THE TAF PERIOD. MOST
CEILINGS WILL BREAK UP AND SCATTER LATER THIS MORNING. VFR FOR
THE REST OF TODAY AND TONIGHT (FRIDAY AND FRIDAY NIGHT.)

&&

.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028>031-035>044-048-049-057.

&&

$$

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

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