Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 231049
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
649 AM EDT MON MAR 23 2015

.SYNOPSIS...
ISSUED AT 104 AM EDT MON MAR 23 2015

AN UPPER LEVEL DISTURBANCE OVER IOWA WILL WEAKEN AS IT MOVES ACROSS
OUR AREA TODAY... BUT STILL RESULT IN SOME ACCUMULATING SNOW...
MAINLY SOUTHWEST OF A BENTON HARBOR TO FORT WAYNE LINE. HIGH
PRESSURE OVER ONTARIO WILL CAUSE FAIR WEATHER ACROSS OUR AREA
TONIGHT. HIGHS TODAY WILL BE IN THE LOWER TO MIDDLE 30S... WITH LOWS
TONIGHT IN THE LOWER TO MIDDLE 20S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM EDT MON MAR 23 2015

SHRTWV OVER NRN IA EARLY THIS MORNING IS EXPECTED TO GRDLY SHEAR
OUT/WEAKEN AS IT MOVES ESE TO CENTRAL OH BY THIS EVE. SYSTEM IS MOVG
ALONG A STRONG LOW LEVEL BAROCLINIC ZONE RESULTING IN STRONG LOW
LEVEL WAA/DEEP LIFT AHEAD OF IT... WITH SUFFICIENT MOISTURE TO THE
S-SW TO CAUSE HEAVY SNOWFALL UPSTREAM ACROSS SE MN/SW WI. ALTHOUGH
THE SYSTEM WILL BE IN DECAYING STAGES AS IT MOVES INTO OUR AREA
TODAY... APPEARS THERE WILL BE SUFFICIENT LOW-MID LEVEL THETA-E
ADVECTION/FGEN FORCING WITH WK MID LEVEL STABILITY (H7-H5 LAPSE
AROUND 6C/KM) TO SUPPORT PRECIP. THUS... BUMPED UP POPS/QPF OVER
MOST OF THE AREA FOR TODAY. EVAPORATIONAL COOLING/TOP DOWN
SATURATION SHOULD RESULT IN MAINLY A SNOW EVENT...THOUGH A BRIEF
PERIOD OF LIGHT RAIN OR DRIZZLE PSBL TOWARD END OF PRECIP AS MID
LEVELS DRY OUT. SWE EXPECTED TO ONLY BE 8:1 OR LESS GIVEN WARM
GROUND TEMPS AND THERMAL PROFILE BUT SNOWFALL RATES SHOULD
COMPENSATE SOMEWHAT. FCST 1-2 INCHES OF WET SNOW ACCUM SW 1/2 OF
CWA...TAPERING TO LITTLE OR NO ACCUM OVER THE FAR NE PORTION. GIVEN
POTENTIAL FOR MESO-BANDING IN THIS TYPE OF SITUATION LOCALLY HIGHER
AMOUNTS AND SHARP SNOWFALL GRADIENTS ARE PSBL. CLOUD COVER AND
PRECIP MOVG IN WITH DRY LOW LEVELS RESULTING IN SGFNT EVAPORATIONAL
COOLING SHOULD PREVENT TEMPS FROM RISING MUCH TODAY... EXPECT HIGHS
IN THE M30S.

FAIR WX WILL RETURN TONIGHT... AS THE SHRTWV MOVES EAST OF THE
AREA AND RIDGING ALOFT BUILDS IN. DECREASING CLOUDINESS AND SOME
SNOW COVER SHOULD ENHANCE RADIATIONAL COOLING... EXPECT LOWS
MAINLY IN THE L-M20S.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 348 AM EDT MON MAR 23 2015

ACTIVE PERIOD STARTING RIGHT OUT THE GATE AS TROUGH WILL STRENGTHEN
AS IT MOVES FROM THE CENTRAL PLAINS LATE MONDAY NIGHT TO THE WESTERN
GREAT LAKES BY WEDNESDAY MORNING. BAND OF RAINSHOWERS WILL TRY TO
MAKE PROGRESS INTO THE AREA TUESDAY AFTERNOON...BUT WILL LIKELY
FIGHT WITH DRY AIRMASS IN PLACE INITIALLY. INCREASING ISENTROPIC
LIFT TUESDAY NIGHT WILL EVENTUALLY OVERCOME THE DEFICIT IN MSTR AND
ALLOW FOR A WIDESPREAD AREA OF RAINSHOWERS FOR MUCH OF THE REGION.
CHANCES FOR THUNDER STILL LINGER ACROSS A GOOD CHUNK OF THE FORECAST
AREA AS A TONGUE OF NEAR OR SLIGHTLY BELOW ZERO SHOWALTER SLIDES
THROUGH ASSOCIATED WITH STRONGEST FORCING AND THETA E ADVECTION.
HAVE TRENDED FASTER WITH DEPARTURE OF PRECIP ON WEDNESDAY WITH THE
AFTERNOON HOURS LIKELY DRY AND RATHER BREEZY AS STRONG MIXING TAKES
PLACE. GUIDANCE HAS BEEN TRENDING LOWER WITH HIGHS PAST COUPLE OF
RUNS BUT HAVE NOT FALLEN INTO THE TREND AS POTENTIAL EXISTS FOR
MIXING HIGH ENOUGH TO LET TEMPS SOARS WELL INTO THE 60S.

A WARM NIGHT WILL BE ON TAP FOR THE AREA WEDS NGT AS RISING HEIGHTS
OCCUR ONCE AGAIN AS HIGHER AMPLITUDE TROUGH DIGS THROUGH THE PLAINS
AND TOWARDS THE REGION. TIMING AND TRACK OF THIS FEATURE ARE A BIT
MORE VARIABLE WITH GFS FASTEST AND ECMWF SLOWEST (ALSO FURTHEST
SOUTHEAST). HAVE INCREASED POPS SOMEWHAT WITH EMPHASIS ON SE AREAS.

SHARPLY COLDER TEMPERATURES WILL ARRIVE FRIDAY INTO SATURDAY AS 850
MB TEMPS PLUMMET WELL BELOW ZERO CELSIUS. ECMWF IS COLDEST WITH GFS
BACKING OFF SOMEWHAT ON EXTENT OF COLD AIR. REGARDLESS...GUIDANCE
NUMBERS FROM MEN/MEX/ECE ALL LEAN TOWARDS HIGHS FRIDAY OF 15 TO 20
DEGREES BELOW NORMAL AND ONLY SOME MODERATION ON SATURDAY. MAY BE
SOME LAKE EFFECT RAIN/SNOW SHOWERS AROUND THURS NGT INTO FRI AS
COLDEST AIR MOVES OVERHEAD. DRY AIR MAY WIN OUT AND ALLOW POPS TO BE
DROPPED BUT FOR NOW GIVEN TRACK/TEMP DIFFERENCES OPTED TO LEAVE
ALONE. ROLLER COASTER CONTINUES TOWARDS THE END OF THE PERIOD WITH
TEMPS TRYING TO CLIMB BACK TOWARDS NORMAL AS UPPER LEVEL RIDGING
OCCURS AGAIN...ACCOMPANIED BY CHANCES FOR PRECIP.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 646 AM EDT MON MAR 23 2015

AREA OF SNOW OVER SRN WI/NRN IL ASSOCIATED WITH SHRTWV MOVG INTO NW
IL WILL OVERSPREAD NRN INDIANA THIS MORNING. IFR WITH OCNL LIFR
CONDITIONS ARE EXPECTED LATE MORNING/EARLY AFTN AS THIS SYSTEM MOVES
THROUGH. SOME LINGERING MVFR LIKELY AFTER SNOW ENDS THIS AFTN INTO
THIS EVE... BECOMING VFR OVERNIGHT AS DRY LOW LEVEL FLOW EMANATING FROM
HIGH OVER SE ONTARIO BECOMES RE-ESTABLISHED.

&&

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

$$

SYNOPSIS...JT
SHORT TERM...JT
LONG TERM...FISHER
AVIATION...JT


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