095  
FXUS63 KIWX 012056  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
356 PM EST SUN FEB 1 2015  
   
SYNOPSIS
 
 
ISSUED AT 355 PM EST SUN JAN 31 2015  
 
LOW PRESSURE WILL MOVE NORTHEAST THROUGH SOUTHERN INDIANA TODAY  
AND INTENSIFY. THE LOW WILL PUSH INTO CENTRAL PENNSYLVANIA BY  
MONDAY MORNING. AS THIS MAJOR WINTER STORM CONTINUES...EXPECT  
MODERATE TO HEAVY SNOW TO CONTINUE INTO THE EVENING. THEN  
INCREASING WINDS WILL CREATE BLOWING AND DRIFTING SNOW FOR MUCH OF  
THE REGION THROUGH TONIGHT. TRAVEL WILL BECOME DIFFICULT TO  
IMPOSSIBLE ACROSS MOST OF THE REGION THROUGH TONIGHT. SNOW WILL  
DIMINISH THEN END FROM WEST TO EAST BY LATE TONIGHT AS THE SYSTEM  
PULLS OFF TO THE EAST. SOME LINGERING LIGHT LAKE EFFECT SNOW  
SHOWERS ARE POSSIBLE ACROSS SOUTHWEST LOWER MICHIGAN AND NORTHWEST  
INDIANA ON MONDAY. ANOTHER SYSTEM MAY BRING ADDITIONAL...BUT  
LESSER SNOW ACCUMULATIONS TO PORTIONS OF THE SOUTHERN GREAT LAKES  
REGION TUESDAY NIGHT INTO EARLY WEDNESDAY.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH MONDAY)  
ISSUED AT 351 PM EST SUN FEB 1 2015  
 
LEAVING ONGOING WSW AND REMAINING AMOUNTS/SENSIBLE WX LARGELY IN  
TACT. TREMENDOUS /UPWARDS OF 250 PERCENT OF NORMAL PWAT TAP  
POIGNANTLY DEPICTED BY RUC14 I290K SFC WITH 50-60 KT ASCENDING  
JETLET INTO FAR SRN IN ATTM. MESOBANDING TODAY HAS BEEN QUITE  
MODULATED AND TRANSITORY IN NATURE...SO WHILE A FEW SPOTS IN  
HEAVIEST BAND MAY EXCEED 15 INCHES...DONT ANTICIPATE A LARGE  
NUMBER OF OUTLIERS. CONTRAST TO GRANT/BLACKFORD AND JAY  
COUNTIES...ESPECIALLY THEIR SRN HALVES...LESSER AMOUNTS OWING TO  
WARM PROFILES/EARLIER MIXED PRECIP TO LIKELY YIELD AT/JUST BELOW  
FINAL ACCUMS.  
 
BOTH PRESENCE OF TROWAL THIS EVENING AND INCREASED STATIC  
STABILITY PER RUC/NAM PROFILES SHOULD ALSO PRECLUDE MOD-EXTREME  
CONVECTIVE ELEMENTS. STILL MOD/OCNL HEAVY SNOW ASSOCD WITH STORM  
RELATIVE ISENTROPIC LIFT THROUGH EARLY TONIGHT...THEN QUICKLY  
BECOMING PARALLEL TO SFCS FROM WEST TO EAST IN 06-12 UTC MON PD.  
BY AND LARGE NRN IL TO ERN IA PRIMARY MID LEVEL DEFORMATION AXIS  
WITHIN 700-600MB LAYER TO CONGEAL WITH ANOTHER RAPIDLY NEWD MOVG  
MAXIMA EMANATING FM CNTL IL...NOW INTO NERN IL/NWRN IN TO TRACK  
THROUGH SWRN LWR MI. PRIMARY AXIS THROUGH EARLY TONIGHT THEN  
ALIGNS WITHIN MID LEVEL COL FROM KLAN TO KBMI BY 04 UTC THEN SRN  
TAIL DEFORMATION BAND QUICKLY SWEEPS CWA PROVIDING LAST POTNL FOR  
ACCUM SNOWFALL...THOUGH WITH THINNING/DESCENDING DGZ APPROACHING  
SFC...THE DEPLETION OF MID LVL MOISTURE WITH PASSAGE OF DRY  
SLOT...AND THE RELAXING UVM PROFILES...SUGGESTS OVERALL RATES  
ANTICIPATED TO BE INCREASINGLY MUTED IN W-E FASHION ACRS CWA IN  
03-08 UTC TIMEFRAME. FINAL SHORT/NEAR TERM ISSUE DEALS WITH BLSN  
THAT SHOULD INCREASE ACRS ENTIRE CWA AS SLR INCREASE TO NEAR 15  
TO 1 IN LATTER PART OF EVENT. RAMPING/BACKING FROM NORTHEAST TO  
EAST AS SFC LOW CONTS TO DEEPEN AT APPROX RATE OF  
1MB/2HRS...TRACKING ALONG I70 CORRIDOR THEN TO WCNTL PA BY  
DAYBREAK. QUASI-STEADY MAINTENANCE OF 10-12MB/3HR CROSS  
ISALLOBARIC DIFFERENCES TO BRING WIND GUSTS TO 20-30 MPH...AND  
WHILE SUB BLIZZARD CONDS EXPECTED...CERTAINLY BLSN TO SUPPLANT  
+SN AS THE MOST SIGNIFICANT HAZARD/IMPACT THROUGH THE NIGHT. MOST  
CONCERN WITH E-W OPEN AREA/RURAL/COUNTY ROADS TO BE IMPACTED AS  
SFC WINDS PROGRESSIVELY BACK.  
 

 
   
LONG TERM
 
(MONDAY NIGHT THROUGH SUNDAY)  
ISSUED AT 351 PM EST SUN FEB 1 2015  
 
AS ONE SYSTEM IS DEPARTING THE NEXT WILL BE QUICKLY MOVING IN  
FROM THE NORTHWEST TO BRING ANOTHER CHANCE FOR LIGHT SNOW TO  
MAINLY NORTHERN PORTIONS OF THE FORECAST AREA (ALONG AND NORTH OF  
ROUTE 30). FEW CHANGES HAVE BEEN MADE AS OVERALL TIMING AND TRACK  
SEEM TO BE REASONABLE WITH A SWATH OF AN INCH OR 2 OF SNOW  
EXPECTED NORTH OF 30 AND DUSTING TO AT MOST AN INCH SOUTH. COLDER  
AIR WILL MOVE BACK IN AGAIN BEHIND THE SYSTEM...BUT ONLY BE A  
GLANCING BLOW WITH HIGHS DROPPING FROM THE 20S TUES/WEDS INTO THE  
TEENS ON THURSDAY BEFORE HEADING BACK INTO THE 20S. LAKE RESPONSE  
EXPECTED BEHIND THIS SYSTEM WITH MORE OF A MULTI BAND SETUP.  
COULD BE SOME LOCAL ACCUMULATIONS BUT SHOULDN'T BE ANYTHING  
SIGNIFICANT.  
 
A WEAK TROUGH WILL MOVE FROM THE WEST COAST ON FRI NGT INTO SAT  
AND MOVE RAPIDLY TOWARDS THE AREA BY SUNDAY. A COLD FRONT WILL  
DROP SOUTH WHICH MAY BRING ADDITIONAL CHANCES FOR LIGHT SNOW. CHC  
POPS WARRANTED AT THIS POINT OVER THE WEEKEND. BELOW NORMAL  
TEMPERATURES EXPECTED THROUGH THE LATTER HALF OF THE WEEK INTO  
THE WEEKEND.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)  
ISSUED AT 1248 PM EST SUN FEB 1 2015  
 
HEAVIEST SNOWFALL RATES COMBINED WITH BR/FZFG TO SUPPORT  
PRIMARILY LIFR CONDS AT LEAST THROUGH LATE AFTERNOON/EARLY  
EVENING. GRADUALLY VERTICAL MOTION AND THERMAL PROFILES WILL LEND  
TO LESSENED RATES WITH IMPROVED CONDITIONS...WITH TRANSITION TO  
BLSN AS PRIMARY VSBY REDUCING ELEMENT. FINALLY CONDS ABOVE  
FUELING/ALTERNATE CRITERIA BY DAYBREAK AS SFC LOW BEGINS TO  
ACCELERATE EWD...WITH SFC LOW INTO CNTL PA BY 12 UTC.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...WINTER STORM WARNING UNTIL 4 AM EST /3 AM CST/ MONDAY FOR  
INZ003>009-012>018-020-022>027-032>034.  
 
MI...WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR MIZ081.  
 
WINTER STORM WARNING UNTIL 4 AM EST MONDAY FOR MIZ077>080.  
 
OH...WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR OHZ001-002-004-  
005-015-016-024-025.  
 
LM...NONE.  

 
 

 
 
SYNOPSIS...MURPHY  
SHORT TERM...MURPHY  
LONG TERM...FISHER  
AVIATION...MURPHY  
 
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