Area Forecast Discussion
Issued by NWS Northern Indiana

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KIWX 250817
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
317 AM EST THU DEC 25 2014

.SYNOPSIS...
ISSUED AT 1215 AM EST THU DEC 25 2014

A FEW LINGERING SNOW SHOWERS AND PATCHY DRIZZLE CAN BE EXPECTED
EARLY THIS MORNING BEHIND A LOW PRESSURE SYSTEM LIFTING INTO
CANADA. DRY OTHERWISE TODAY INTO FRIDAY AS HIGH PRESSURE BUILDS
IN. TEMPERATURES WILL CONTINUE TO BE WARMER THAN NORMAL...REACHING
NEAR 40 DEGREES TODAY AND INTO THE MID 40S ON FRIDAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM EST THU DEC 25 2014

QUIET/DRIER WX ON TAP TODAY INTO TONIGHT AS MID LEVEL RIDGING
OVERSPREADS IN WAKE OF DEEP CYCLONE LIFTING NORTH THROUGH WESTERN
QUEBEC. AMPLE LEFTOVER LOW LEVEL MOISTURE WITHIN STRENGTHENING
SUBSIDENCE INVERSION SHOULD KEEP BKN-OVC LOW CLOUDS LOCKED IN
THROUGH AT LEAST THE MID AFTERNOON...WITH ANY LINGERING SCT
FLURRIES/PATCHY DRIZZLE LIFTING OUT OF THE AREA FROM SW TO NE
EARLY THIS MORNING. OTHERWISE...MILD FOR LATE DECEMBER WITH WARM
ADVECTION/SW FLOW QUICK TO KICK BACK IN LATER TODAY-TONIGHT IN
ADVANCE OF NEXT SHORTWAVE DROPPING INTO THE FOUR CORNERS.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 317 AM EST THU DEC 25 2014

BROAD SOUTHWESTERLY LOW LEVEL FLOW AND RELATIVELY MILD CONDITIONS TO
BEGIN THE PERIOD AS LOCAL AREA BECOMES POSITIONED IN UPPER LEVEL
INFLECTION ZONE DOWNSTREAM OF SOUTHWEST CONUS LONGWAVE TROUGH.
FRIDAY IS SHAPING UP AS A RELATIVELY MILD DAY DUE TO POSITIONING OF
BROAD LOW LEVEL THERMAL RIDGING ACROSS THE REGION...AND POTENTIAL OF
AT LEAST SOME INSOLATION. LOW LEVEL THETAE ADVECTION SHOULD RAMP UP
LATER IN AFTERNOON AND ESPECIALLY BY FRIDAY NIGHT WITH EXPECTATION
THAT LOW STRATUS SHOULD TEND TO FILL IN ACROSS THE AREA FRIDAY
NIGHT. DEPENDING ON THIS LOW CLOUD EVOLUTION...HIGHS COULD PUSH INTO
THE UPPER 40S FRIDAY ACROSS THE SOUTH...BUT HAVE NOT STRAYED FAR
FROM INHERITED LOW TO MID 40S HIGHS AT THIS TIME. PRECIP CHANCES
APPEAR TO BE QUITE LOW DURING THE EVENING FRIDAY AS STRONGER UPPER
FORCING REMAINS WEST/SOUTHWEST OF THE AREA AND MOISTURE OF
ANY NOTE REMAINS QUITE SHALLOW. MOISTURE DEPTH SHOULD INCREASE SOME
LATE FRIDAY NIGHT AS AXIS OF STRONGER LOW LEVEL THETAE ADVECTION
SHIFTS NORTHEASTWARD...AND HAVE MAINTAINED SOME LOW CHANCE LIGHT
RAIN POPS IN THE 06Z-12Z PERIOD WHICH MAY END UP TO BE MORE OF A
PATCHY DRIZZLE SCENARIO.

BY SATURDAY...CHANNELED VORTICITY MAXIMUM EMANATING FROM SHEARING
UPPER LEVEL WAVE ACROSS THE ROCKIES SHOULD ALLOW FOR INCREASED
PRECIP CHANCES...ALONG WITH A POTENTIAL OF AT LEAST A BRIEF PERIOD
OF DEEPER MOISTURE PROFILES IN THE VICINITY OF ASSOCIATED LOW/MID
LEVEL TROUGH AXIS. A BIT CONCERNED THOUGH THAT MOISTURE DEPTH MAY
CONTINUE TO BE IN ISSUE INTO SATURDAY...AND MUCH OF THIS WILL DEPEND
ON EXACT STRENGTH OF SOUTHERN/CENTRAL ROCKIES PV ANOMALY AS IT GETS
INGESTED INTO THE MID MS VALLEY. HAVE GENERALLY TAKEN A BLENDED
APPROACH BETWEEN THE STRONGER GEM/EC AND WEAKER GFS IN HANDLING
NORTHEASTWARD EJECTION OF THIS TROUGH...AND THIS BLENDED APPROACH
FITS WELL INTO PREVIOUSLY FORECASTED MID TO HIGH CHANCE -RA POPS FOR
SATURDAY. THE INCREASINGLY SHEARED NATURE TO UPPER WAVE MAY ALLOW
FOR ENOUGH LOW/MID LEVEL FRONTOGENESIS TO PERSIST LONG FOR A BRIEF
PERIOD OF SOME SNOW TOWARD ENDING OF PRECIP SATURDAY EVENING...BUT
STILL EXPECTING LITTLE OR NO ACCUMULATION IF THIS SCENARIO WERE TO
UNFOLD.

FOR MONDAY...MEDIUM RANGE MODELS STILL DEPICT 1050+ MB SFC HIGH
OVERSPREADING NORTHERN PLAINS IN WAKE OF SOUTH CENTRAL CANADIAN
UPPER LOW...WITH A TREND TO COLDER CONDITIONS FOR THE EARLY PARTS OF
NEXT WEEK. GUIDANCE HAS BACKED OFF ON MAGNITUDE OF COLD AIR FOR THIS
PERIOD HOWEVER...WITH ACTUALLY REASONABLE AGREEMENT IN 00Z EC/GFS IN
TRENDING TO MORE OF SOUTHWEST CONUS CUT-OFF UPPER TROUGH. OUTSIDE OF
POTENTIAL LAKE EFFECT SNOW SHOWERS EARLY NEXT WEEK...HAVE MAINTAINED
DRY FORECAST WITH EXPECTATION THAT STRONG LOW LEVEL ANTICYCLONE
SHOULD TEND TO SUPPRESS ANY SHORT WAVES KICKING OUT OF SOUTHWEST
CONUS CUT-OFF TROUGH. A FEW WEAK PERTURBATIONS IN NORTHWEST UPPER
FLOW IN A MORE MOISTURE STARVED NORTHERN STREAM COULD ALLOW FOR A
FEW PERIODS OF LIGHT SNOW/FLURRIES GIVEN EXPECTED STRONG
BAROCLINICITY ACROSS THE REGION...BUT NOTHING THAT APPEARS WORTH A
MENTION AT THIS TIME. PRECIP CHANCES MAY EVENTUALLY INCREASE JUST
OUTSIDE OF THIS FORECAST PERIOD AS CUT OFF UPPER TROUGH EVENTUALLY
GETS INGESTED BACK INTO MAIN BELT OF WESTERLIES BUT CONFIDENCE AT
THIS FORECAST DISTANCE OBVIOUSLY QUITE LOW.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1215 AM EST THU DEC 25 2014

RESIDUAL LOW LEVEL MOISTURE UNDER A STRENGTHENING SUBSIDENCE
INVERSION WILL ALLOW LOW MVFR STRATUS TO HANG IN THROUGH AT LEAST
MID AFTERNOON. TRENDED VFR BY LATE AFTERNOON/EVENING WITH
EXPECTATIONS FOR STRONG SUBSIDENCE AND SOME DRYING TO MIX OUT
STRATOCU. OTHERWISE...LOW CHANCE FOR BRIEF IFR-MVFR VIS
RESTRICTIONS WITH ISO-SCT SNOW SHOWERS/PATCHY DRIZZLE EARLY THIS
MORNING.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ043-
     046.

&&

$$

SYNOPSIS...STEINWEDEL
SHORT TERM...STEINWEDEL
LONG TERM...MARSILI
AVIATION...STEINWEDEL


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.