Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 222201
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
501 PM EST THU JAN 22 2015

.SYNOPSIS...
ISSUED AT 430 PM EST THU JAN 22 2015

QUIET WEATHER WILL ROUND OUT THE WORK WEEK. TONIGHT...CLOUDY SKIES
WILL BEGIN TO DIMINISH. LOWS WILL BOTTOM OUT IN THE LOW TO MID 20S
ACROSS THE REGION. PARTLY CLOUDY SKIES WILL PREVAIL ON
FRIDAY...WITH HIGHS RISING INTO THE MID TO UPPER 30S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 500 PM EST THU JAN 22 2015

BROAD STRETCHING OF MID-LEVEL TROF OVER THE GREAT LAKES BETWEEN THE
SOUTHERN STREAM STORM AND THE NEXT CLIPPER MOVING OUT THE CANADIAN
ROCKIES. BOUNDARY LAYER AND SURFACE HIGH PRESSURE EXTENDING FROM THE
CENTRAL PLAINS INTO THE GREAT LAKES EXPECT TO WEAKEN THROUGH FRIDAY
EVENING. MAY SEE SOME FOG / LOW STRATUS EARLY IN THE MORNING FRIDAY
BUT OTHERWISE NO MEASURABLE PRECIPITATION IS EXPECTED.

AS THE HIGH PRESSURE WEAKENS...EXPECT TO SEE THE LOW LEVEL
INVERSION ERODE DURING THE EARLY MORNING HOURS FRIDAY. FRIDAYS MAX
TEMPERATURES SHOULD INCREASE A FEW DEGREES OVER TODAY.

SHORT TERM AND HIGH RES MODELS IN GOOD AGREEMENT FOR THE NEXT 24-30
HOURS AND HAVE ONLY MODIFIED THE CURRENT FORECAST GRIDS SLIGHTLY
OVER PREVIOUS GRIDS.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 500 PM EST THU JAN 22 2015

THE CHALLENGES IN THIS PERIOD INCLUDE THE TRACK...AMOUNT OF SNOW AND
TYPE OF PRECIPITATION WITH THE CLIPPER SYSTEM SUNDAY INTO EARLY
SUNDAY NIGHT. NCEP AND OTHER MODELS CONTINUE TO STRUGGLE WITH THE
HANDLING OF THE SYSTEM. A VERY LARGE SPREAD OF GFS ENSEMBLE MEMBERS
TRACK AND CENTRAL PRESSURE OF THE SURFACE LOW WERE INDICATIVE OF THE
ISSUES HANDLING OF THIS SYSTEM. GFS ENSEMBLE CENTRAL PRESSURE
DIFFERENCES RANGE FROM 980 MB TO AROUND 1000 MB. HAVE REJECTED THE
ECMWF TRACK WITH ITS SOUTHERN SOLUTION IN LIEU OF A MORE NORTHERN
SOLUTION SUPPORTED BY THE GFS. MANY GFS ENSEMBLE MEMBERS INCLUDING
THE OPERATIONAL RUN FAVOR A LOW TRACK OVER FAR SOUTH LOWER MICHIGAN.
THIS TRACK IS SUPPORTED BY CLIPPER CLIMATOLOGY AND CIPS ANALOGS.
ISENTROPIC LIFT ON THE 290K SURFACE WITH SPECIFIC HUMIDITIES OVER
3G/KG SUPPORT SNOWFALL AMOUNT OF GENERALLY 2 TO 4 INCHES OVER FAR
NORTHEAST AREAS...WITH MUCH LESSER AMOUNTS FARTHER SOUTHWEST.
OTHERWISE...FOR THE REST OF THIS UPCOMING WEEK...CHALLENGES WITH THE
EXTENT OF ARCTIC AIR OVER THE AREA AND THE TIMING OF CLIPPER SYSTEMS
IN STRONG NW FLOW. FOR NOW...KEPT MONDAY THROUGH WEDNESDAY BELOW
NORMAL...WITH MODERATING TEMPERATURES THURSDAY.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 122 PM EST THU JAN 22 2015

A WEAK WAVE RIDING OVER THE STRATUS FIELD CONTINUES TO GENERATE
VERY LIGHT SNOW / DRIZZLE OVER THE FAR SOUTHEAST PORTION OF THE
FORECAST AREA. VISIBLE SATELLITE SHOWS SEVERAL BANDS OF CLOUDS
RIDING OVER THE INVERSION AND THESE TOO COULD TRIGGER SEEDING OF
THE STRATUS FOR LIGHT SNOW/DRIZZLE THROUGH LATE AFTERNOON TODAY.

GIVEN THE SHORT RANGE MODEL SOUNDINGS HINTING THAT THE STRATUS
WILL BREAK UP DURING THE EARLY PART OF THE DAY ON FRIDAY. THIS
SHOULD BE SHORT LIVED AS THE STORM TO THE SOUTH SHIFTS INTO THE
SOUTHEASTERN STATES AND NORTHERN INDIANA IS AGAIN SUBJECT TO
OVERRUNNING AND EASTERLY SURFACE FLOW.

&&

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

$$

SYNOPSIS...MCD
SHORT TERM...LEWIS
LONG TERM...SKIPPER
AVIATION...LEWIS


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