Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 250849
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
349 AM EST WED FEB 25 2015

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

&&

.SYNOPSIS...
ISSUED AT 347 AM EST WED FEB 25 2015

A CLIPPER SYSTEM WILL MOVE THROUGH CENTRAL INDIANA TONIGHT AND
THURSDAY BRINGING CHANCES FOR SNOW TO THE AREA AND A REINFORCING
SHOT OF COLD AIR. HIGH PRESSURE WILL BRING DRY WEATHER FOR FRIDAY
THROUGH SATURDAY...WHEN ANOTHER SYSTEM BRINGS CHANCES FOR SNOW AND
MIXED PRECIPITATION TO THE AREA FOR THE REMAINDER OF THE WEEKEND.
UPPER WAVES WILL BRING MORE CHANCES FOR PRECIPITATION FOR THE WORK
WEEK AS WELL...WITH TEMPERATURES POSSIBLY WARM ENOUGH FOR ALL RAIN
ON TUESDAY.

&&

.NEAR TERM /TODAY/...

ISSUED AT 347 AM EST WED FEB 25 2015

THE DAY WILL START OUT MOSTLY CLEAR BUT AN APPROACHING UPPER WAVE
WILL BRING AN INCREASE IN CLOUD COVER FROM THE NORTHWEST AS THE DAY
PROGRESSES. TEMPERATURES ALOFT ACTUALLY WARM UNTIL MIDDAY SO
COMBINING THAT WITH THE EXPECTED EARLY SUNSHINE SHOULD SEE
TEMPERATURES CLIMB TO AT LEAST WHERE THEY GOT YESTERDAY AND PERHAPS
WARMER IN THE SOUTH. THUS LEANED TOWARD THE WARMER END OF THE
GUIDANCE NUMBERS

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...

ISSUED AT 347 AM EST WED FEB 25 2015

FORECAST FOCUS IS ON SNOW CHANCES EARLY IN THE SHORT TERM. MODELS
ARE IN GOOD AGREEMENT AND GENERALLY USED A CONSENSUS. A SPLIT FLOW
PATTERN WILL BRING A CLIPPER SYSTEM TO THE AREA TONIGHT AND ANOTHER
WAVE THROUGH THE SOUTHEASTERN U.S. UPPER FORCING WITH THE
CLIPPER...WHILE NOT ROBUST...LOOKS SUFFICIENT OVER AT LEAST THE
NORTHWESTERN COUNTIES TO PRODUCE SOME SNOW OVERNIGHT. ALSO SEEING
SOME STACKING OF LOW LEVEL AND UPPER LEVEL FORCING IN CROSS SECTION
WITH A BIT OF INSTABILITY BETWEEN AND THIS SHOULD SERVE TO BUMP
AMOUNTS UP A BIT FROM WHERE THEY MIGHT BE OTHERWISE. THAT SAID
MODELS DEPICT THE SOUTHERN SYSTEM MONOPOLIZING THE MOISTURE AND
BLOCKING MOST OF IT FROM REACHING HERE. THUS WITH SUFFICIENT FORCING
BUT LITTLE MOISTURE TO WORK WITH HAVE STUCK WITH THE HIGH END OF POP
GUIDANCE FOR TONIGHT BUT WENT WITH LIGHT QPF AND SNOWFALL AMOUNTS UP
TO AN INCH OR SO IN THE NORTHWEST WITH LOWER AMOUNTS ELSEWHERE.

THIS SET OF MODEL RUNS DRAGS OUT THE SYSTEM A LITTLE MORE SO WILL
CONTINUE WITH HIGH CHANCES FOR SNOW THROUGH THE DAY ON THURSDAY.
THURSDAY NIGHT WILL CONTINUE TO CARRY A SLIGHT CHANCE FOR SNOW AS
THE UPPER TROUGH AXIS IS HEADED TOWARD THE AREA. BY FRIDAY MORNING
THOUGH HIGH PRESSURE MOVING IN WILL PUT AN END TO ANY SNOW CHANCES.

FOR TEMPERATURES STUCK WITH A MOS/MODEL CONSENSUS. LOWS TONIGHT
SHOULD STAY UP IN THE TEENS WITH CLOUDS AND SNOW CHANCES...BUT AFTER
THAT BELOW ZERO LOWS ARE AROUND FOR THURSDAY NIGHT AND FRIDAY NIGHT.
TEMPERATURES DURING THE DAY THURSDAY WILL LIKELY STAY STEADY OR FALL
IN THE WAKE OF THE CLIPPER.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 242 PM EST TUE FEB 24 2015

PRIMARY FOCUS FOR THE EXTENDED CONTINUES TO BE ON COMPLEX AND
PROLONGED PERIOD OF PRECIPITATION SET TO IMPACT THE OHIO VALLEY AS
A SERIES OF WAVES TRACKS THROUGH THE REGION.

THE WEEKEND WILL START DRY AND BITTERLY COLD WITH STRONG HIGH
PRESSURE SLOWLY MOVING AWAY TO THE EAST. ONE MORE SUBZERO NIGHT
CERTAINLY APPEARS PLAUSIBLE FRIDAY NIGHT WITH THE HIGH CENTERED
JUST TO OUR EAST. CLOUDS WILL GRADUALLY INCREASE LATE SATURDAY
WITH LIGHT SNOW DEVELOPING SATURDAY NIGHT. EXTENDED MODELS
CONTINUE TO ADJUST TO A PATTERN SHIFT ALOFT AS UPPER WAVE TRACKING
OUT OF THE PACIFIC NORTHWEST CARVES OUT A DEEP TROUGH OVER THE
WESTERN U S. DOWNSTREAM OF THE TROUGH...QUASI- ZONAL TO SOUTHWEST
FLOW WILL DOMINATE EAST OF THE ROCKIES...PUMPING IN PROGRESSIVELY
DEEPER MOISTURE INTO THE OHIO AND TENNESSEE VALLEY BEGINNING
SATURDAY NIGHT AND CONTINUING INTO EARLY NEXT WEEK.

WHILE DETAILS REMAIN MURKY AT THIS EARLY STAGE...SOME NOTICEABLE
TRENDS HAVE STARTED TO DEVELOP OVER THE LAST COUPLE MODEL RUNS.
BULK OF THE MODELS ARE COLDER IN THE BOUNDARY LAYER FOR SUNDAY AND
MONDAY. A COUPLE OF REASONS FOR THIS...MORE ENERGY ALOFT IS BEING
HELD BACK IN THE WESTERN TROUGH...LEADING TO A BROAD OVERRUNNING
SETUP AS OPPOSED TO A STRONGER SYSTEM TRACKING THROUGH THE OHIO
VALLEY LATE WEEKEND. ADDITIONALLY...PRESENCE OF A SECONDARY AREA
OF HIGH PRESSURE POISED TO SINK INTO THE MID MISSISSIPPI VALLEY BY
THE END OF THE WEEKEND. BOTH OF THESE FACTORS SUPPORT MORE
SUPPRESSION AND CONSEQUENTLY A COLDER SCENARIO. HAVE TRENDED
TOWARDS MORE SNOW THROUGH MONDAY AND LIMITED ANY MIXING TO
SOUTHERN COUNTIES. CONSIDERING THE DIFFICULTY THE MODELS HAVE HAD
IN PROPERLY SAMPLING THE SNOWPACK AND ITS IMPACTS ON NEAR SURFACE
TEMPS...MAY SEE FURTHER ADJUSTMENTS TOWARDS COLDER BOUNDARY LAYER
CONDITIONS IN THE COMING DAYS.

A MORE ROBUST PIECE OF ENERGY EJECTS OUT MONDAY NIGHT AND IS
LIKELY TO DEVELOP A SURFACE WAVE INTO THE OHIO AND TENNESSEE
VALLEYS TUESDAY AS THE UPPER JETS PHASE. THIS SYSTEM DEPENDING ON
ITS TRACK HAS A MUCH BETTER OPPORTUNITY TO PULL WARMER AIR ALOFT
NORTH INTO THE REGION AND CREATE A SLOPPY WINTRY MIX. INTERESTING
TO NOTE AT THIS PRELIMINARY STAGE THAT MODEL CONSENSUS TAKES THE
WAVE JUST SOUTH OF THE FORECAST AREA. WILL CARRY A MIX FOR MOST OF
THE AREA TUESDAY BUT ANY SHIFT FURTHER SOUTH TO THE SYSTEM WOULD
INTRODUCE A GREATER THREAT FOR SNOW. STILL SEVERAL DAYS AWAY FROM
STARTING TO HONE IN ON SPECIFICS WITH THIS SYSTEM.

&&

.AVIATION /DISCUSSION FOR THE 250600Z TAF ISSUANCE/...

ISSUED AT 1129 PM EST TUE FEB 24 2015

VFR CONDITIONS THIS MORNING AND THE FOR THE MOST PART TODAY. LOWER
FLIGHT CATEGORIES ANTICIPATED TONIGHT AS A CLIPPER SYSTEM MOVES
ACROSS THE AREA.

REMOVED ALL MENTION OF EVEN TEMPO GROUPS FOR KIND AND KLAF WITH -SHSN
AS CONDITIONS LOOK TOO DRY. WEAK HIGH PRESSURE WILL BUILD IN AND
SHIFT TO THE EAST QUICKLY THIS MORNING WITH MID LEVEL CLOUDS
ARRIVING FROM THE WEST BY MIDDAY IN ADVANCE OF A CLIPPER MOVING
INTO THE MISSOURI VALLEY. WINDS WILL SHIFT TO N/NW LATER THIS MORNING
THEN BECOME LIGHT AND VARIABLE...AND INCREASE AROUND 06Z
THURSDAY AHEAD OF THE CLIPPER SYSTEM.

&&

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

$$

SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...SMF

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