Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 051152
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
652 AM EST THU MAR 5 2015

.SYNOPSIS...
ISSUED AT 436 AM EST THU MAR 5 2015

AN ARCTIC AIRMASS ACROSS THE AREA WILL PROVIDE MUCH BELOW NORMAL
TEMPERATURES TODAY...ALONG WITH THE POTENTIAL OF ISOLATED TO
SCATTERED LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES. A RIDGE OF
HIGH PRESSURE WILL MOVE INTO THE AREA TONIGHT PROVIDING LIGHT
WINDS...CLEAR SKIES...AND CONTINUED COLD CONDITIONS. THIS RIDGE OF
HIGH PRESSURE WILL BEGIN TO SHIFT EAST OF THE AREA ON FRIDAY WHICH
WILL MARK THE BEGINNING OF A MODERATING TEMPERATURE TREND THAT
WILL CONTINUE INTO NEXT WEEK.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 436 AM EST THU MAR 5 2015

POSITIVELY TILTED UPPER TROUGH WILL TRACK ACROSS THE GREAT LAKES
REGION TODAY...ALTHOUGH VERY DRY PROFILES WILL LIMIT PRECIP CHANCES
TO ANYTHING MORE THAN LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES.
SOME EVIDENCE IN OBSERVATIONAL DATA IN PAST FEW HOURS OF SOME
SHARPENING OF LAND BREEZE/LAKE THERMAL TROUGHING BUT CONTINUED LARGE
SCALE SYNOPTIC SUBSIDENCE AND RELATIVELY LARGE MID LEVEL DEW POINT
DEPRESSIONS HAVE CONTINUED TO PROVIDE VERY WEAK LAKE RESPONSE TO
THIS POINT. PASSAGE OF AFOREMENTIONED SYNOPTIC TROUGH IN THE 12Z-18Z
TIMEFRAME MAY PROVIDE A BRIEF PERIOD OF LIGHT SCATTERED LAKE EFFECT
SNOW SHOWERS BUT SEE NO REASON TO DEVIATE FROM PREVIOUS LOW POPS.
PASSAGE OF UPPER VORT MAX LATER THIS MORNING INTO THIS AFTERNOON
COUPLED WITH STEEP LOW LEVEL LAPSE RATES COULD BE SUFFICIENT FOR
SOME FLURRIES FURTHER INLAND NORTHEAST INDIANA/SOUTHERN LOWER
MICHIGAN. ARCTIC AIRMASS WILL BE ENTRENCHED ACROSS THE AREA TODAY
BUT WILL CONTINUE TO SIDE WITH THE "WARMER" ENVELOPE OF MOS
NUMBERS GIVEN PRESENCE WELL MIXED NORTHWEST FLOW...STEEP LOW
LEVEL LAPSE RATES...AND LOWERING SNOW ALBEDOS. GIVEN ABOVE
FACTORS...THIS SHOULD SUPPORT HIGHS IN THE UPPER TEENS TO AROUND
20 MOST LOCATIONS.

BY LATE AFTERNOON/EARLY EVENING LOW LEVEL WINDS WILL BEGIN TO BACK
IN RESPONSE TO APPROACHING LOW LEVEL RIDGE AXIS. UPPER TROUGH
TRACKING ACROSS EASTERN PORTIONS OF THE FORECAST AREA LATE THIS
AFTERNOON COMBINED WITH EASTWARD PROGRESSION OF LAKE ENHANCED LOW
CLOUDS MAY SUPPORT PARTLY-MOSTLY CLOUDY CONDITIONS THIS EVENING
ACROSS THE EAST...BUT TRENDING TO CLEAR/MOSTLY CLEAR ACROSS ALL OF
THE FORECAST AREA LATER THIS EVENING. DESPITE CORE OF LOW LEVEL
THERMAL TROUGHING TO MIGRATE EAST OF THE AREA TONIGHT...GOOD
RADIATIONAL COOLING CONDITIONS SHOULD SUPPORT LOWS IN THE 5 ABOVE
TO 5 BELOW ZERO RANGE...WITH WIND CHILLS AS COLD AS 10 BELOW EARLY
FRIDAY MORNING.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 436 AM EST THU MAR 5 2015

THE SURFACE HIGH PRESSURE AREA WILL HAVE SHIFTED SOUTHEAST OF THE
AREA AT THE START OF THIS PERIOD FRIDAY MORNING. TEMPERATURES SHOULD
TRY TO START TO CLIMB OUT OF THE DEEP FREEZE FRIDAY...BUT UPSTREAM
SNOW COVER AND PROXIMITY OF THE COLD AIR MASS WILL STILL KEEP
TEMPERATURES CLOSE TO 20 DEGREES BELOW NORMAL. FAVOR THE NAM/MET
WITH TEMPERATURES FALLING LITTLE FRIDAY NIGHT...BUT RISING TO
BETWEEN 35 AND 40 SATURDAY. TEMPERATURES SHOULD CONTINUE TO REBOUND
AND CLIMB ABOVE NORMAL EARLY NEXT WEEK. NATIONAL OPERATIONAL
HYDROLOGIC REMOTE SENSING CENTER SHOWS MODELED SNOW WATER EQUIVALENT
HIGHEST OVER FAR SOUTHWEST LOWER MICHIGAN INTO EXTREME NORTHERN
INDIANA WHERE AMOUNTS ARE 2 TO 4 INCHES WITH LOCALLY HIGHER AMOUNTS.
CONCERN FOR THE POTENTIAL FOR MELTING SNOW TO CAUSE LOWLAND FLOODING
AND RISES ON AREA RIVERS. VIRTUALLY NO PRECIPITATION IS EXPECTED
THROUGH THE MIDDLE OF NEXT WEEK...SO THIS WILL HELP ALLEVIATE THE
FLOOD POTENTIAL SOMEWHAT. HOWEVER...IT IS POSSIBLE THAT THERE MAY BE
SOME EVENTUAL ICE JAMS ON THE RIVERS AS THE SNOW MELTS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 631 AM EST THU MAR 5 2015

THE COMBINATION OF ARCTIC AIR MASS OVER LAKE MICHIGAN AND A
SYNOPTIC UPPER LEVEL TROUGH MOVING ACROSS THE SOUTHERN GREAT LAKES
WILL PRODUCE SCATTERED LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES
THROUGH MIDDAY. MVFR CIGS AROUND 3K FT ARE POSSIBLE THIS MORNING AT
KSBN...WITH OTHERWISE VFR CONDITIONS EXPECTED TO PREVAIL. LIGHT
NORTH WINDS THIS MORNING SHOULD MIX OUT TO WEST NORTHWEST AROUND 10
KNOTS THIS AFTERNOON...BECOMING LIGHT AND VARIABLE THIS EVENING.
EASTWARD MIGRATION OF CENTRAL CONUS ANTICYCLONE SHOULD RESULT IN
LIGHT SOUTHWEST WINDS TOWARD THE END OF THE PERIOD.

&&

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

$$

SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...SKIPPER
AVIATION...MARSILI


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