Area Forecast Discussion
Issued by NWS Indianapolis, IN

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287
FXUS63 KIND 120900
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
400 AM EST FRI FEB 12 2016

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

&&

.SYNOPSIS...
ISSUED AT 323 AM EST FRI FEB 12 2016

BELOW NORMAL TEMPERATURES WILL PERSIST THROUGH THE WEEKEND AS
CENTRAL INDIANA REMAINS UNDER THE NORTHWEST FLOW OF A BROAD LOW
PRESSURE SYSTEM OVER EASTERN ONTARIO. NORTHWEST FLOW WILL BE
CONDUCIVE TO PERIODIC LAKE EFFECT SNOW SHOWERS ACROSS NORTHEAST
PORTIONS OF CENTRAL INDIANA INTO TOMORROW. MEANWHILE...THE
REMAINDER OF CENTRAL INDIANA WILL REMAIN DRY THOUGH AS HIGH
PRESSURE STRENGTHENS OVER THE UPPER MIDWEST. THE DRY WEATHER WILL
BE SHORT-LIVED THOUGH AS THE NEXT SYSTEM ENTERS THE GREAT LAKES
REGION ON SUNDAY AND MONDAY. THE PATTERN REMAINS ACTIVE AT THAT
POINT AS ANOTHER UPPER LOW TRACKS ACROSS THE LOWER MIDWEST AROUND
MID-WEEK.

&&

.NEAR TERM /TODAY AND TONIGHT/...

ISSUED AT 323 AM EST FRI FEB 12 2016

THE MAIN FOCUS OF THE NEAR TERM PERIOD WILL BE SNOW SHOWER
CHANCES.

WEAK PERTURBATIONS IN THE UPPER FLOW WILL BE RESPONSIBLE FOR LIGHT
SNOW SHOWERS THROUGHOUT THIS MORNING AND AFTERNOON. CURRENT RADAR
MOSAIC IS SHOWING ENHANCEMENT ACROSS CENTRAL ILLINOIS THAT SHOULD
START AFFECTING CENTRAL INDIANA AROUND DAYBREAK. AS DYNAMICS
WEAKEN THIS EVENING...SNOW SHOWERS WILL ONLY BE FUELED OVER THE
NORTHEASTERN COUNTIES BY LAKE EFFECTS. TOTAL SNOW AMOUNTS SHOULD
BE UP TO 1 INCH.

TEMPS THIS AFTERNOON WILL TOP OFF IN THE MID 20S TO LOW 30S...BUT
STRONG RADIATIONAL COOLING WITH HIGH PRESSURE/CLEARING TONIGHT
WILL RESULT IN SINGLE DIGIT TEMPERATURES. STRONG NORTHWEST WINDS
OF 10 TO 20 MPH WILL CREATE WIND CHILLS IN THE -5 TO -15 RANGE.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...

ISSUED AT 323 AM EST FRI FEB 12 2016

THE MAIN FOCUS OF THE SHORT TERM PERIOD WILL BE SNOW CHANCES WITH
THE NEXT SYSTEM.

LIGHT LAKE EFFECT SNOW SHOWERS WILL PERSIST INTO SATURDAY OVER THE
NORTHEAST COUNTIES...BUT ACCUMULATIONS WILL BE MINIMAL. HIGH
PRESSURE WILL CONTINUE TO STRENGTHEN OVER THE AREA BY THAT
POINT...AND DRY CONDITIONS WILL PREVAIL THROUGH SATURDAY NIGHT.
FOCUS THEN TURNS TO THE NEXT SYSTEM...PROGGED FOR SUNDAY/SUNDAY
NIGHT. MODELS ARE IN AGREEMENT WITH SNOW SHOWERS STARTING ACROSS
WESTERN PORTIONS OF CENTRAL INDIANA BY SUN 12Z...THEN EXPANDING
EASTWARD THROUGHOUT THE DAY. BEST ISENTROPIC LIFT APPEARS TO BE
DURING THE SUN 18Z-MON 00Z TIME FRAME...WHICH COULD RESULT IN A
QUICK 1 TO 3 INCHES OF SNOWFALL.

TEMPERATURES WILL MODERATE BY SUNDAY AS FLOW BECOMES SOUTHERLY.
AFTER A FRIGID DAY ON SATURDAY WITH HIGHS ONLY IN THE
TEENS...DAYTIME HIGHS WILL TOP OFF IN THE LOW TO MID 20S BY
SUNDAY. MEANWHILE...OVERNIGHT LOWS WILL BE BITTER COLD ON SATURDAY
NIGHT WITH READINGS IN THE SINGLE DIGITS.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 316 AM EST FRI FEB 12 2016

A LOT OF MOVING PARTS IN REGARDS TO THE EARLY WEEK SYSTEM POISED
TO AFFECT THE EASTERN U S AND THE 00Z MODEL SUITE DID LITTLE TO
INCREASE THE LOW CONFIDENCE IN HIGHLIGHTING SPECIFIC IMPACTS TO
CENTRAL INDIANA. THE EXTENDED PERIOD WILL BE ACTIVE WITH VARIOUS
SNOW THREATS THROUGH MIDWEEK BEFORE A WARMING TREND COMMENCES FOR
THE SECOND HALF OF THE WEEK.

NORTHERN STREAM CLIPPER SYSTEM WILL SWING THROUGH THE LOWER GREAT
LAKES LATE SUNDAY AND EARLY MONDAY AND WILL PRESENT CHANCES FOR
SNOW. AT THE SAME TIME...LOW PRESSURE ORGANIZING OVER THE LOWER
MISSISSIPPI VALLEY WILL TRACK NORTHEAST INTO THE LOWER APPALACHIANS
BY TUESDAY. ADDITIONALLY...OP GFS AND ECMWF BOTH TRACK ANOTHER
CLIPPER INTO THE MID MISSISSIPPI VALLEY. THE 00Z RUNS OF THE
OPERATIONAL MODELS ARE TRACKING THE MAIN SYSTEM EAST OF THE
APPALACHIANS AND ARE SUGGESTIVE OF LESS OF AN IMPACT TO THE REGION
WITH NO PHASING WITH THE CLIPPER TO THE NORTHWEST. GFS ENSEMBLE
MEMBERS ON THE OTHER HAND ARE ALL OVER THE PLACE WITH THE SURFACE
LOW TRACK DUE TO VARYING DEGREES OF PHASING IN THE UPPER LEVELS.
FURTHER MUDDYING THE WATERS IS THE MARGINAL TEMPS IN THE NEAR
SURFACE LAYER WHICH ARGUES FOR EVEN THE POSSIBILITY FOR OTHER PRECIP
TYPES TO MIX IN WITH SNOW FOR A TIME ON MONDAY AND TUESDAY.

THE UPPER LEVEL FLOW AND TELECONNECTION PATTERN SUGGESTS
POTENTIAL IS THERE FOR SOME SHIFT NORTH AND WEST TO THE MAIN
SYSTEM. WITH THE PRIMARY UPPER WAVE STILL OUT OVER THE PACIFIC AND
NOT FULLY SAMPLED YET...FUTURE MODEL RUNS TODAY AND SATURDAY WILL
BE CRITICAL IN DETERMINING IF THE MAIN STORM SHIFTS LEFT AND
PRESENTS A GREATER IMPACT TO PARTS OF THE FORECAST AREA FOR EARLY
WEEK. AT THIS TIME HOWEVER...ATTEMPTING TO EMPLOY ANY DETAIL
INCLUDING POTENTIAL SNOWFALL AMOUNTS IS POINTLESS. WILL CARRY
CHANCES OF SNOW MONDAY AND TUESDAY WITH A POSSIBILITY FOR RAIN TO
MIX IN ACROSS THE SOUTH TUESDAY AS CRITICAL LOW LEVEL THICKNESSES
WARM.

HIGH PRESSURE WILL BRING DRIER WEATHER TO THE REGION BY
MIDWEEK...WITH EXPANDING RIDGING ALOFT AND STRONG SOUTHERLY FLOW
PROVIDING A NICE WARMUP BY THE END OF THE WEEK AS TEMPERATURES GO
ABOVE NORMAL.

&&

.AVIATION /DISCUSSION FOR THE 120900Z TAF UPDATE/...
ISSUED AT 316 AM EST FRI FEB 12 2016

LITTLE CHANGE NEEDED FOR THE EARLY MORNING UPDATE. SEEING AREA OF SNOW
SHOWERS IMPACT CENTRAL ILLINOIS AS THEY MOVE SOUTHEAST. ANY
IMPACTS AGAIN LOOK PRIMARILY FOCUSED ON THE KBMG AND KHUF
TERMINALS THROUGH MID MORNING.

06Z DISCUSSION FOLLOWS.

UPPER DISTURBANCE CURRENTLY DROPPING SOUTHEAST THROUGH NORTHERN MISSOURI
IS EXPECTED TO SETTLE INTO WESTERN KENTUCKY AROUND SUNRISE FRIDAY. COULD
BE SOME LIGHT SNOW AT THE TERMINALS ROUGHLY 121000Z-121600Z ASSOCIATED WITH
THIS FEATURE...MAINLY IN THE KHUF/KBMG AREAS...BUT IT APPEARS ANY
IFR VISIBILITY RESTRICTIONS WILL REMAIN SOUTHWEST OF THE TERMINALS
CLOSER TO VORTICITY CENTER.

OTHERWISE...EXPECTING CEILINGS TO GRADUALLY LOWER OVERNIGHT AND INTO THE
MORNING HOURS ON FRIDAY...EVENTUALLY FALLING INTO THE MVFR CATEGORY TOWARDS
MIDDAY FRIDAY AS COLD ADVECTION DEVELOPS IN THE WAKE OF THE DISTURBANCE.

LIGHT SURFACE WINDS OVERNIGHT EXPECTED TO BECOME 260-280 DEGREES AT 10-13 KTS
BY MIDDAY FRIDAY.


&&

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

$$

SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JAS/RYAN



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