000
FXUS63 KIWX 232120
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
420 PM EST FRI JAN 23 2015

.SYNOPSIS...
ISSUED AT 400 AM EST FRI JAN 23 2015

MOSTLY CLOUDY SKIES WILL CONTINUE THROUGH THE OVERNIGHT HOURS WITH
LOW TEMPERATURES IN THE MID 20S. HIGH TEMPERATURES ON SATURDAY WILL
BE IN THE MID 30S WITH A FEW LIGHT SNOW SHOWERS POSSIBLE.
ACCUMULATING SNOWFALL IS EXPECTED IN THE SOUTHERN GREAT LAKES REGION
ON SATURDAY NIGHT INTO SUNDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 417 PM EST FRI JAN 23 2015

CLOUDS CONTINUED OVER MOST OF THE FORECAST AREA THIS AFTERNOON WITH
A WEAK RIDGE OF HIGH PRESSURE NORTH OF THE OHIO RIVER. SOME BREAKS
IN THE CLOUDS HAD DEVELOPED FROM MARION TO LIMA. THE FORECAST AREA
WAS TEMPORARILY IN AN INACTIVE COL AREA...BETWEEN THE DEVELOPING LOW
TO THE SOUTH AND THE APPROACHING SHORTWAVE TROF AND ASSOCIATED
SURFACE TROF TO THE WEST. DIURNAL RISES WITH LOW SUN ANGLE...SOME
SNOW COVER AND CLOUDY SKIES HAD WERE ALMOST NON EXISTENT TODAY AT FT
WAYNE...WITH A ONE DEGREE RISE THROUGH MID AFTERNOON.

MID DAY AIRCRAFT OBSERVATIONS AND EARLY MORNING REGIONAL SOUNDINGS
SHOWED THE INVERSION DEEPENING FROM NORTHEAST TO SOUTHWEST. GIVEN
THIS INVERSION WITH THE COL AREA IN CLOSE PROXIMITY...THE MODELS
APPEAR TO BE CLEARING SKIES AND IMPROVING CONDITIONS TOO FAST...
ESPECIALLY THE GFS. HAVE GONE MORE PESSIMISTIC WITH CLOUD
COVER...ALTHOUGH SOME BREAKS IN THE CLOUDS ARE LIKELY EARLY TONIGHT
AHEAD OF THE APPROACHING TROF. A LARGE DRY ARE ABOVE THE BASE OF THE
SUBSIDENCE INVERSION WILL LIMIT SNOWFALL. GIVEN WEAK DYNAMICS AND
THIS DRY AREA...KEPT LOW SNOW CHANCES WITH NO SNOW ACCUMULATIONS
EXPECTED THROUGH SATURDAY AFTERNOON.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 417 PM EST FRI JAN 23 2015

UPR AIR PATTERN OVER THE EASTERN PACIFIC AND NORTH AMERICA WILL BE
UNDERGOING AMPLIFICATION AT START OF THIS PERIOD. SHRTWV/SFC LOW
EXPECTED TO DIG SE FROM THE NRN PLAINS TO THE MID MS VALLEY SAT NGT
AND THROUGH THE OHIO VALLEY SUN-SUN NGT. MODELS CONTG TO TREND TRACK
OF LOW MORE TO THE S-SW... WITH MORE NORTHERLY TRACK FCST BY NAM
STILL THE OUTLIER. DECENT AGREEMENT IN STRONG FORCING/DEEP MOISTURE
(PWAT AROUND 0.5" AND H7 MIXING RATIO AROUND 2.5G/KG) ACCOMPANYING
THIS SYSTEM WITH LOW LEVEL FGEN... AND MID LEVEL DEFORMATION ZONE
ALONG WITH A WEAKLY STABLE H85-H5 LAYER AND SATURATED DGZ CO-LOCATED
WITH MAXIMUM UVM SUNDAY. FOLLOWING MODEL TREND/CONSENSUS... ADJUSTED
AXIS OF HEAVIEST SNOWFALL (STORM TOTAL 3-5") SOUTH WITH SLIGHTLY
LOWER TEMPS CWA-WIDE SAT NGT-SUNDAY.

LOW WILL MOVE OUT OF THE REGION SUNDAY NIGHT WITH A WK HIGH PRESSURE
RIDGE BUILDING INTO THE AREA IN ITS WAKE. THIS COULD RESULT IN A
CLEARING SKIES/LIGHT WIND/FRESH SNOWPACK SCENARIO. JUST LOWERED MINS
A FEW DEGREES AS CLEARING FCST RATHER UNCERTAIN ATTM.

FAIR WX WITH BLO NORMAL TEMPS EXPECTED MONDAY AS RIDGE LINGERS OVER
THE AREA. A WK ALBERTA CLIPPER MAY CAUSE SOME LIGHT SNOW AS IT MOVES
THROUGH THE AREA MONDAY NIGHT-TUE...CURRENT FCST TRACK FAVORS
HIGHEST POPS WRN PORTION OF CWA. ANOTHER WK RIDGE EXPECTED TO
MOVE THROUGH TUE NGT RESULTING IN BLO NORMAL TEMPS AGAIN WITH LOWS
RANGING FROM THE SINGLE DIGITS NE TO THE TEENS SW.

SHRTWV EXPECTED TO MOVE EAST FROM THE NRN PLAINS TO THE GRTLKS WED
NGT-THU PROVIDING A WARMUP WITH HIGHS IN THE U30S THU. WK
FORCING/LIMITED MOISTURE EXPECTED OVER OUR AREA WITH THIS SYSTEM SO
JUST A LOW CHC OF RAIN/SNOW FCST IN THIS TIMEFRAME. JUST MODERATELY
COLDER AIRMASS WITH HIGHS IN THE 20S EXPECTED BEHIND THIS SYSTEM
FRIDAY AS ANOTHER HIGH PRESSURE SYSTEM MOVES IN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 23 2015

A WEAK RIDGE OF HIGH PRESSURE WAS NORTH OF THE OHIO RIVER...LIKE
AN INACTIVE COL AREA BETWEEN THE DEVELOPING LOW TO THE SOUTH AND
THE APPROACHING SHORTWAVE TROF AND ASSOCIATED SURFACE TROF TO THE
WEST. AIRCRAFT OBSERVATIONS AND EARLY MORNING REGIONAL SOUNDINGS
SHOWED THE INVERSION DEEPENING FROM NORTHEAST TO SOUTHWEST. GIVEN
THIS INVERSION WITH THE COL AREA IN CLOSE PROXIMITY...THE MODELS
APPEAR TO BE CLEARING SKIES AND IMPROVING CONDITIONS TOO FAST...
ESPECIALLY THE GFS. HAVE GONE MORE PESSIMISTIC WITH IMPROVING
CONDITIONS GIVEN ALL OF THESE FACTORS AS BOTH SBN AND FWA OBS
STILL NEAR 015 OVC. THEREFORE... KEPT MVFR AT BOTH SITES FOR THE
ENTIRE TAF PERIOD AT 17Z. TAFS STILL MAY BE TOO OPTIMISTIC WITH
CEILING IMPROVEMENT TO 020...BUT STILL HOPEFUL OF THIS IMPROVEMENT
GIVEN THE 020 MINIMUM FOR FUEL ALTERNATE.

&&

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

$$

SYNOPSIS...EB
SHORT TERM...SKIPPER
LONG TERM...JT
AVIATION...SKIPPER


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