000
FXUS63 KIWX 300524
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1224 AM EST SAT NOV 30 2013

.SYNOPSIS...
ISSUED AT 429 PM EST FRI NOV 29 2013

A RIDGE OF HIGH PRESSURE WILL CONTINUE TO PROVIDE QUIET WEATHER TO
THE REGION TONIGHT. THIS RIDGE OF HIGH PRESSURE WILL MOVE OFF TO
THE EAST LATE TONIGHT INTO SATURDAY. AN UPPER LEVEL DISTURBANCE
WILL TRACK INTO THE GREAT LAKES REGION ON SUNDAY...BUT
PRECIPITATION WITH THIS SYSTEM WILL REMAIN NORTH OF THE REGION
ACROSS THE NORTHERN GREAT LAKES. ANOTHER RIDGE OF HIGH PRESSURE
WILL THEN BUILD INTO THE AREA ON SUNDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 344 PM EST FRI NOV 29 2013

TRANQUIL WEATHER WILL PERSIST THIS PERIOD AS THE SURFACE HIGH MOVES
EAST AND AS RETURN FLOW STARTS TO INCREASE. LOWERED LOWS SOME OVER
NORTHEAST AREAS WHERE RETURN FLOW WILL BE THE WEAKEST AND WHERE
THERE SHOULD BE ENOUGH BREAKS IN CLOUDS FOR TEMPS TO DROP INTO THE
LOWER 20S. SOME CONCERN FOR LOWS TO BE LOCALLY COLDER OVER SNOW
COVERED AREAS...BUT FOR NOW BLENDED THE GFS AND MET WITH A LOW OF 24
AT SBN. OTHERWISE...UPSTREAM CLOUDS WILL SPREAD ACROSS THE AREA
OVERNIGHT...AND THEN SHOULD CLEAR OUT SATURDAY ALLOWING TEMPERATURES
TO RISE TO AROUND 40 AND LOWER 40S AS WARM AIR ADVECTION CONTINUES.


&&

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 344 PM EST FRI NOV 29 2013

WATER VAPOR IMAGERY DEPICTING SHORT WAVE OVER NORTHERN SASKATCHEWAN
THIS AFTERNOON THAT WILL BE THE FIRST OF A COUPLE OF WEAK
DISTURBANCES TO MOVE ACROSS THE REGION EARLY ON IN THE LONG TERM
PERIOD. LATEST MODEL GUIDANCE HAS THIS FEATURE MOVING ACROSS THE
NORTHERN GREAT LAKES AND SOUTHERN ONTARIO SATURDAY EVENING AND WILL
BRING A WEAK CLIPPER TYPE SFC REFLECTION WITH IT...DRAGGING A
MOISTURE STARVED COLD FRONT ACROSS THE FORECAST AREA EARLY SUNDAY.
SHALLOW LAYER OF LOW LEVEL MOISTURE CENTERED AROUND 850MB LEVEL
EXPECTED TO PROVIDE EXTENSIVE CLOUD COVER BUT LACKING IN DEPTH AND
FORCING FOR ANY MENTION OF PRECIP ATTM. NEXT WEAK SYSTEM CURRENTLY
PROGGED TO DIVE FURTHER SOUTH...MOVING THROUGH THE MID MS AND OH
VALLEYS MONDAY AND MONDAY NIGHT...PLACING OUR FCST AREA IN REGION OF
OVERRUNNING MOISTURE NORTH OF THE SFC BOUNDARY. LACK OF FORCING WILL
AGAIN BE AN ISSUE AS VERY WEAK INDICATION OF UPGLIDE ALONG THE 290K
SFC WILL ACCOMPANY COND PRES DEF AOB 10MB. PATTERN THEN BEGINS TO
SHIFT FROM A NW FLOW TO SW FLOW BY MIDWEEK AS SPLIT FLOW WILL PHASE
AS STRONG SYSTEM COMES ONSHORE IN PACIFIC NW. RESULTING DOWNSTREAM
RIDGING AND HEIGHT RISES OVER THE MIDWEST AND GREAT LAKES WILL SEND
TEMPS ABOVE NORMAL WED AND THU. RAPID LEE SIDE CYCLOGENESIS IN
RESPONSE TO STRONG UPPER LOW WILL HAVE SFC SYSTEM QUICKLY OCCLUDING
AS IT MOVES OUT OF THE NORTHERN PLAINS WED OR THU...AS GFS AND ECMWF
SHOWING TIMING DIFFERENCES. STRONG WAA AHEAD OF THIS SYSTEM WILL TAP
INTO GULF MOISTURE AND BRING BETTER CHANCES FOR PRECIP BY THU.
DESPITE BECOMING VERTICALLY STACKED WITH UPPER LOW AS IT CONTINUES
NE INTO CANADA...STRONG JET DYNAMICS PERSIST BEHIND IT ON SW FLOW AS
MEAN TROF AXIS STAYS ANCHORED OVER WESTERN US. THIS WILL PUSH SYSTEM
UP TOWARD HUDSON BAY AND HAVE COLD FRONT MOVING THROUGH THE AREA BY
THE END OF THE FORECAST PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1224 AM EST SAT NOV 30 2013

VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD. SHEARED OUT
MIDLEVEL WAVE IS CURRENTLY GENERATING SOME HIGH BASED CLOUD COVER
OVER THE REGION BUT VERY DRY LOW LEVEL AIR WILL KEEP CEILINGS WELL
ABOVE 5 KFT. SOUTHEASTERLY WINDS WILL INCREASE AND VEER THROUGHOUT
THE DAY AS THE NEXT COLD FRONT APPROACHES. THIS FRONT MAY BRING
SOME REDUCTION IN FLIGHT CATEGORY BY SUNDAY MORNING BUT NOT UNTIL
AFTER 06Z.

&&

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

$$

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


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

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