Area Forecast Discussion
Issued by NWS Indianapolis, IN

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604
FXUS63 KIND 090748
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
245 AM EST TUE FEB 9 2016

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

&&

.SYNOPSIS...
ISSUED AT 305 PM EST MON FEB 8 2016

AN UPPER LOW WILL SPIN SLOWLY OVER THE LOWER GREAT LAKES THROUGH
MIDWEEK...PRODUCING SNOW SHOWERS ALONG WITH WINDY AND PROGRESSIVELY
COLDER WEATHER THROUGH WEDNESDAY. HIGH PRESSURE WILL RETURN FOR LATE
WEEK WITH DRY AND COLD CONDITIONS. A QUICK MOVING CLIPPER SYSTEM MAY
BRING SNOW FRIDAY...FOLLOWED BY A POTENTIAL LARGER STORM SYSTEM
FOR LATE WEEKEND INTO EARLY NEXT WEEK.

&&

.NEAR TERM /REST OF TONIGHT/...

ISSUED AT 941 PM EST MON FEB 8 2016

UPDATE...
CURRENT FORECAST IS ON TRACK AS CURRENT RADAR MOSAIC SHOWS A BIT
OF A LULL IN SNOW SHOWER ACTIVITY. SNOWFALL AMOUNTS SO FAR HAVE
GENERALLY BEEN UNDER A HALF INCH UP. WILL CONTINUE TO KEEP THE
INCREASING POPS ACROSS THE NORTH LATER IN THE NIGHT THOUGH AS A
500 MB VORT MAX SLIDES INTO THE AREA. MEANWHILE...OVERNIGHT LOWS
ARE STILL EXPECTED TO BOTTOM OUT IN THE LOW 20S. CURRENT TEMPS
ACROSS THE AREA ARE RANGING FROM THE LOW 20S ACROSS THE WESTERN
COUNTIES TO UPPER 20S OVER THE EASTERN COUNTIES. UPDATED GRIDS
HAVE BEEN SENT.

PREVIOUS DISCUSSION...
BEHIND THE FRONT...TEMPS HAVE QUICKLY FALLEN BACK INTO THE UPPER 20S
WITH SNOW SHOWERS CONTINUING. INTENSITY OF THE SNOW SHOWERS HOWEVER
IS WEAKER AND TRAVEL IMPACTS CONTINUE TO REMAIN MINIMAL EVEN WITH
SUBFREEZING TEMPERATURES DEVELOPING. ADDITIONAL AREA OF SNOW SHOWERS
AND OCCASIONAL SQUALLS CURRENTLY OVER CENTRAL ILLINOIS IN
ASSOCIATION WITHIN ANOTHER SPOKE OF ENERGY ALOFT WILL SETTLE INTO
THE REGION WITHIN THE NEXT FEW HOURS. WITH SURFACE TEMPS BELOW
FREEZING...LOSS OF ANY RADIATIONAL EFFECTS FROM DAYLIGHT AND WIND
GUSTS PEAKING AT 25 TO 30 MPH...EXPECT THESE SNOW SHOWERS WILL HAVE
MORE OF AN IMPACT INTO THE EARLY EVENING. ANY SNOW ACCUMS SHOULD
REMAIN LESS THAN AN INCH IN MOST PLACES THROUGH THE EVENING.

IN THE WAKE OF THIS AREA OF SNOW SHOWERS...ANTICIPATE A DECREASE IN
COVERAGE INTO THE EARLY OVERNIGHT WITH SNOW SHOWERS ONCE AGAIN
INCREASING IN COVERAGE AND INTENSITY IN THE PREDAWN HOURS AS THE
850MB TROWAL SWINGS ACROSS THE AREA AND LOW LEVEL FLOW BEGINS TO
CATCH MORE OF A LAKE MICHIGAN FETCH. WILL BRING HIGHER POPS BACK
INTO THE NORTHERN COUNTIES LATE AS A RESULT. WILL CONTINUE WITH THE
SPS TO HIGHLIGHT OCCASIONAL TRAVEL IMPACTS TONIGHT AND EARLY TUESDAY.

TEMPS...TOOK A MODEL BLEND FOR LOWS OVERNIGHT AS TEMPS ARE EXPECTED
TO BOTTOM OUT GENERALLY IN THE LOWER 20S.


&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 305 PM EST MON FEB 8 2016

HIGH IMPACT/LOW ACCUMULATION SNOW SHOWERS AND SQUALLS WILL CONTINUE
THROUGH THE FIRST HALF OF THE SHORT TERM...GRADUALLY FOCUSING MORE
OVER THE NORTHEAST HALF OF THE FORECAST AREA ON WEDNESDAY BEFORE
HIGH PRESSURE FINALLY BUILDS IN FOR WEDNESDAY NIGHT AND THURSDAY.

TUESDAY IS LIKELY TO BE THE DAY THAT CARRIES THE MOST POTENTIAL
IMPACT TO TRAVELERS...AND ESPECIALLY DURING THE AFTERNOON AND
EVENING AS THERMODYNAMIC PROFILES ONCE AGAIN BECOME MORE FAVORABLE
FOR HEAVIER SNOW SHOWERS AND SQUALLS WITH STEEPER LAPSE RATES AND
ANOTHER SURGE OF FORCING ALOFT AS THE UPPER LOW MOVES ACROSS THE
AREA. THE PRESENCE OF A DEEPER SNOW GROWTH ZONE WITHIN THE COLDER
AIRMASS...THE POTENTIAL FOR HIGHER RATIOS AND THE CONTINUED
FAVORABLE LAKE FETCH SUPPORTS THE BEST POTENTIAL FOR LIGHT
ACCUMULATIONS. CONTINUED GUSTY NORTHWEST WINDS WILL CAUSE BLOWING
SNOW AND DRASTICALLY REDUCED VISIBILITIES IN HEAVIER SNOW SHOWERS.
WITH SURFACE TEMPS REMAINING IN THE 20S...ICY ROADS WILL BE AN ISSUE
TOO. THE SPS COVERS THIS WELL...WITH FUTURE SHIFTS TONIGHT AND EARLY
TUESDAY DETERMINING IF AN IMPACT-BASED ADVISORY WOULD BE MORE
BENEFICIAL AS CONDITIONS EVOLVE.

SNOW SHOWERS WILL CONTINUE TUESDAY NIGHT...GRADUALLY FOCUSING OVER
THE EASTERN HALF OF THE FORECAST AREA INTO WEDNESDAY. REMAIN A BIT
SKEPTICAL AT HOW QUICKLY MODEL GUIDANCE IS TRYING TO SHUT DOWN SNOW
SHOWERS WEDNESDAY WITH BACK SIDE ENERGY BEHIND THE DEPARTING UPPER
WAVE WORKING IN TANDEM WITH A MUCH COLDER AIRMASS. EVEN THOUGH
FORCING ALOFT IS WEAKER...STILL EXPECT MOISTURE TO BE SQUEEZED OUT
WITH HOW COLD THE AIRMASS WILL BE. CONTINUED CHANCE POPS MAINLY EAST
OF I-65 WITH POTENTIAL FOR AN ADDITIONAL FEW TENTHS OF AN INCH OF
SNOW BEFORE IT ENDS BY LATE DAY. DRY AND COLD CONDITIONS ARE THEN
EXPECTED FOR WEDNESDAY NIGHT AND THURSDAY AS HIGH PRESSURE BUILDS IN
WITH NORTHWEST FLOW ALOFT.

FOR TOTAL SNOWFALL THIS AFTERNOON THROUGH WEDNESDAY...A GENERAL 1 TO
3 REMAINS A SOLID CALL...WITH HIGHER AMOUNTS FOCUSED OVER THE
NORTHEAST HALF OF THE FORECAST AREA. DO ANTICIPATE THERE WILL BE
LOCALLY HIGHER AMOUNTS WHERE HEAVIER SQUALLS OCCUR...AGAIN MOST
LIKELY FOCUSED OVER THE NORTHEAST HALF OF THE FORECAST AREA.

TEMPS...WENT AT OR JUST BELOW GUIDANCE THROUGH MUCH OF THE PERIOD.
HIGHS WILL STAY IN THE 20S TUESDAY...AND LIKELY REMAIN IN THE TEENS
WEDNESDAY. SUBZERO WIND CHILLS ARE EXPECTED TUESDAY NIGHT THROUGH
EARLY THURSDAY AS WELL.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 245 AM EST TUE FEB 9 2016

BIG MODEL AND ENSEMBLE DIFFERENCES WILL BE A MAJOR HURDLE TO PARTS
OF THE LONG TERM FORECAST INCLUDING POPS AND TEMPERATURES.

VERY FAST NORTHWEST FLOW ALOFT WILL BE IN PLACE AT THE START OF THE
LONG TERM. THIS IS CAUSING SIGNIFICANT SHEARING OF ANY PACIFIC WAVE
THAT CRESTS THE UPPER WESTERN RIDGE AND HEADS TOWARDS THE OHIO
VALLEY. THAT SAID MODELS...ESPECIALLY THE 00Z ECMWF...CONTINUE TO
BRING SOME SNOW TO THE FORECAST AREA ON FRIDAY. WITH CONFIDENCE
LOW...WILL CONTINUE WITH SMALL SNOW CHANCES ON FRIDAY. THEN...MODELS
AGREE THAT JAMES BAY UPPER LOW WILL DROP SOUTHEAST ACROSS NEW
ENGLAND ON SATURDAY. THIS WILL BRING ANOTHER SHOT OF COLD TO THE
OHIO VALLEY. ARCTIC HIGH WILL THE MOVE OVER THE OHIO VALLEY AND
GREAT LAKES ON SATURDAY WITH SOUTHERLY FLOW ON THE BACK SIDE TO
RETURN ON SUNDAY.

THE BIGGEST MODEL AND ENSEMBLE DIFFERENCES WILL BE WITH ANOTHER
WINTER STORM SYSTEM THAT WILL EFFECT CENTRAL INDIANA BY SUNDAY
NIGHT. MODELS MOVE A STRONGER WAVE OVER THE WESTERN RIDGE AND MOVE
IT TO ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY SUNDAY NIGHT INTO
MONDAY. THE 00Z GFS WAS BRINGING A TRAILING FRONT ACROSS ON MONDAY
WITH THE ASSOCIATED SURFACE LOW OVER NORTHERN MICHIGAN.
HOWEVER...THE 00Z ECMWF HAD THE MAIN SURFACE LOW LIFTING NORTHEAST
ACROSS SOUTHERN AND EASTERN INDIANA SUNDAY NIGHT INTO MONDAY. THE
EURO SOLUTION WOULD BRING DECENT SNOW AMOUNTS TO CENTRAL INDIANA
WITH LESSER AMOUNTS IF THE GFS VERIFIES. EITHER WAY...WILL LEAVE
SNOW CHANCES IN THE FORECAST.

TEMPERATURES FRIDAY NIGHT AND SATURDAY WILL LIKELY DEPEND A LOT ON
SNOW COVER AS THERE SHOULD BE AT LEAST PARTIAL CLEARING IN THE WAKE
OF THE CLIPPER AND AS ARCTIC HIGH PRESSURE APPROACHES. NUDGED
REGIONAL BLEND TEMPERATURES DOWN A COUPLE OF DEGREES FOR THAT
PERIOD...BUT IT MAY NOT BE ENOUGH. TEMPERATURES ARE ONLY EXPECTED
TO REBOUND TO CLOSE TO NORMAL BY EARLY NEXT WEEK PER THE BLEND.

&&

.AVIATION /DISCUSSION FOR THE 09/0600Z TAF ISSUANCE/...
ISSUED AT 1143 PM EST MON FEB 8 2016

GENERALLY MVFR OVERNIGHT WITH LIGHT SNOW SHOWERS OVERNIGHT. SNOW SHOWERS
WILL BE MORE NUMEROUS TUESDAY WITH POCKETS OF IFR WHICH WILL BEGIN TO
DIMINISH MONDAY EVENING.

WE WILL REMAIN UNDER A COLD NORTHWEST FLOW WITH SCATTERED TO NUMEROUS
SNOW SHOWERS AS LOW PRESSURE OVER SOUTHERN LAKE HURON MOVES TO THE EASTERN
GREAT LAKES DURING THE NEXT 24 HOURS. EXPECT MINIMAL VISIBILITY RESTRICTIONS
OVERNIGHT...BUT THEN WITH POCKETS OF IFR BY MID MORNING AS SNOW SHOWERS
BECOME MORE NUMEROUS.  THIS WILL CONTINUE MOST OF THE DAY WITH SNOW
SHOWERS LESSENING AGAIN TUESDAY EVENING.

WEST TO NORTHWEST WINDS AROUND 10 KNOTS OVERNIGHT WILL BE 10 TO 15 KNOTS
WITH GUSTS UP TO 25 KNOTS TUESDAY BEFORE DIMINISHING A LITTLE TUESDAY NIGHT.

&&

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

&&

$$

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



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