Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 300631
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
131 AM EST FRI JAN 30 2015

.SYNOPSIS...
ISSUED AT 408 PM EST THU JAN 29 2015

COLDER AIR WILL MOVE IN ACROSS THE GREAT LAKES OVER THE NEXT 24
HOURS. LAKE EFFECT SNOW SHOWERS WILL IMPACT PORTIONS OF NORTHERN
INDIANA AND SOUTHWESTERN LOWER MICHIGAN INTO FRIDAY AFTERNOON
BEFORE DIMINISHING. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 20S
WHERE LAKE EFFECT CLOUDS PERSIST...TO THE MIDDLE TEENS ELSEWHERE.
TEMPERATURES WILL RISE LITTLE ON FRIDAY WITH HIGHS IN THE LOWER TO
MIDDLE 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

FIRST OF 3 WAVES WAS NOW MOVING THROUGH WESTERN OHIO WITH AN AREA OF
RAIN JUST AHEAD OF IT. NW WINDS WERE NOW BLOWING ACROSS MUCH OF THE
AREA WITH SOME GUSTS IN THE 25 TO 30 MPH RANGE. BEHIND THE
WAVE...PRECIP HAS WENT TO MORE OF A FLURRY/DRIZZLE SETUP AS ICE
PRODUCTION AND DEEPER LIFT APPEARS TO HAVE DEPARTED FOR THE MOMENT.
THIS WILL BE SHORT LIVED AS NEXT WAVE WAS RIGHT ON ITS HEELS
CURRENTLY WRAPPING UP OVER EAST IOWA/NW ILLINOIS BRINGS IN COLDER
LOW LEVEL TEMPS AND TRANSITION TO ALL SNOW FOR WHATEVER IS LEFT
OVER. LAKE EFFECT SNOW SHOWERS WILL MATERIALIZE LATE AFTERNOON INTO
THIS EVENING...BUT REMAIN WEAK AND DISORGANIZED AS MARGINAL DELTA
T`S PREVAIL. ENOUGH DEVELOPMENT SHOULD EXIST TO STILL WARRANT LIKELY
POPS DOWNWIND OF THE LAKE FOR THIS EVENING.

LAST WAVE...CURRENTLY ENTERING NORTHERN MINNESOTA...WILL RAPIDLY
DROP SOUTHEAST AND IMPACT THE REGION LATER TONIGHT INTO FRIDAY. BEST
LAKE EFFECT CHANCES WILL ARRIVE WITH THIS FEATURE AS 850 MB TEMPS
DROP TO -14 TO -16 C BY 12Z FRIDAY. A FAVORABLE FETCH DOWN THE WEST
PART OF THE LAKE CURVING EAST WOULD ALLOW FOR SOME STRONGER BAND
POTENTIAL. INVERSION HGTS WILL PEAK AROUND 7 KFT BRIEFLY BEHIND THE
WAVE BUT CO LOCATION WITH DGZ AND BEST LIFT WILL NEVER FULLY
COINCIDE. IN ADDITION...BANDS WILL LIKELY BE MOVING AROUND AS FLOW
VARIES BETWEEN 310 AND 330 DEGREES MUCH OF THE EVENT. ALL THESE
FACTORS SHOULD LIMIT AND THEN SLOWLY FALL. THIS SHOULD LIMIT
ACCUMULATIONS TO THE 1 TO 2 INCH RANGE.

IN TERMS OF TEMPERATURES...LOWS WILL DROP OFF INTO THE TEENS LATER
TONIGHT FOR MOST LOCATIONS WITH AREAS SHELTERED BY LAKE EFFECT
CLOUDS DROPPING IN THE LOWER TO MIDDLE 20S. ONLY A MINOR DIURNAL
SWING IN TEMPS IS EXPECTED ON FRIDAY.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 408 PM EST THU JAN 29 2015

COMPLEX AND VIGOROUS UPSTREAM INTERACTION BETWEEN MULTITUDE OF
SHORTWAVES BEGINNING TO CONVERGE INTERMODEL CONSENSUS. SURFACE RIDGE
OVHD FRIDAY EVENING WITH WEAK CLIPPER SYSTEM PUSHING SEWD THROUGH
NRN PLAINS. MOISTURE LACKING WITH BNDRY CONTG TO SLIDE SEWD THROUGH
GRTLKS SAT. FURTIVE SWD DIG OF HEIGHT FALL CENTROID TOWARD BAJA
CUTOFF SUPPORTING FARTHER SWD CYCLOGENESIS EMANATING OUT OF ARKLATEX
SUN AND INTO TN VALLEY SUN NIGHT. STILL STRONG OPEN/POSITIVE TILTED
7H WAVE WITH NRN FRINGE OF HFC PROVIDING 100-120M/12 HR HEIGHT
ADJUSTMENTS CARVES THROUGH SRN TIER CWA. HAVE MUTED POPS 00-06 UTC
SUNDAY WITH CONCERNS OF MODELS A BIT FAST IN OVERCOMING PRIOR
100-150MB LOW LEVEL CONDENSATION PRESSURE DEFICITS...BUT THEN RAMP
RAPIDLY BY 12 UTC. WHILE ENTIRE EVENT I280-285K ISENT UPGLIDE NOT
ASTOUNDING...THOUGH SYSTEM RELATIVE FLOW ESPECIALLY IN LWR LEVELS
ALONG WITH SIG MOISTURE FLUX CONVERGENCE INTO FAR SRN TIER CWA.
RAMPED POPS SUN...ESPECIALLY FAR SRN TIER ANTICIPATORY OF BEING ON
NRN FRINGE OF MARKED SNOWFALL GRADIENT. RICH BULK MOISTURE AROUND 3
G/KG 1000-850MB LAYER SUN ACRS SRN CWA...GRADUALLY LOWERS TO 2 G/KG
BY LATE AFTN/EVE AS SURFACE RESPONSE TIGHTENS SIGNIFICANTLY AND WELL
SOUTH OF CWA. BRIEF LES RESPONSE SUN NIGHT THOUGH QUICKLY ENDING
MONDAY AS PRIMARY SYSTEM FURTHER DEEPENS OFF MID ATL COAST...DRAWING
DRIER AIR/LOW SUBSIDENCE INVERSION THROUGH WRN GRLKS. WEAK CLIPPER
SYSTEM PSBL TUE/TUE NIGHT...FOLLOWED BY MEAGER LAKE RESPONSE INTO
MIDWEEK AS TROF SHARPENS THROUGH LWR GRTLKS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 123 AM EST FRI JAN 30 2015

SCATTERED SNOW SHOWERS TO CONTINUE OVER THE NEXT SEVERAL
HOURS...WITH TRANSITION TO MORE PURE LAKE EFFECT SNOW SHOWERS
AFTER 09Z. A STRONG UPPER VORT MAX DROPPING ACROSS THE SOUTHERN
GREAT LAKES REGION HAS ENHANCED COVERAGE/INTENSITY OF SCATTERED
SNOW SHOWERS ACROSS THE REGION. STRONGEST FORCING WITH THIS SHORT
WAVE WILL SLIP EAST OF THE TERMINALS AFTER 09Z...WITH CONTINUED
SCATTERED SNOW SHOWERS EXPECTED TO AFFECT KSBN THROUGH FRIDAY
MORNING. WILL MAINTAIN PRIMARILY MVFR CONDITIONS WITH THE PERIODIC
SNOW SHOWERS AT KSBN...ALTHOUGH VERY BRIEF PERIODS OF IFR VSBYS
ARE POSSIBLE WITH THE HEAVIER SNOW SHOWERS. INTENSITY OF LAKE
EFFECT SNOW SHOWERS SHOULD DIMINISH AFTER 12Z AS INVERSION HEIGHTS
CONTINUE TO LOWER...WITH TOTAL ACCUMULATIONS AT KSBN GENERALLY
LESS THAN AN INCH EXPECTED. A REINFORCING SURFACE TROUGH
ACCOMPANYING THIS STRONGER UPPER VORT MAX WILL CONTINUE TO ALLOW
FOR A PERIOD OF NORTHWEST WIND GUSTS AROUND 25 KNOTS...WHICH
SHOULD SLOWLY DIMINISH TOWARD DAYBREAK. CIGS IN THE 2500-3500 FT
RANGE MAY PERSIST INTO MUCH OF FRIDAY AS SYNOPTIC SUBSIDENCE
STRENGTHENS LOW LEVEL INVERSION HELPING TO TRAP LOW CLOUDS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

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


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