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000
FXUS63 KIWX 232045
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
445 PM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 443 PM EDT THU MAY 23 2013

HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST TONIGHT...AND
REMAIN OVER THE AREA THROUGH THE WEEKEND. THIS WILL BRING BELOW
NORMAL TEMPERATURES AND GENERALLY CLEAR SKIES OVER THE NEXT FEW
DAYS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

SURFACE COLD FRONT MOVED THROUGH THE FORECAST AREA
THIS MORNING WHICH BROUGHT A ROUND OF LIGHT RAIN THROUGH MOST OF THE
AREA. RAIN SHOWERS AND DRIZZLE HAVE CONTINUED DREARY CONDITIONS
THROUGH THE DAY DUE TO CVA AHEAD OF A S/W TROUGH DIGGING INTO THE
LOWER GREAT LAKES. THESE CONDITIONS WERE EXACERBATED IN OUR
NORTHWESTERN AREAS WHERE AN EXTENSIVE MARINE LAYER HAS ADVECTED AS
FAR INLAND AS ELKHART AND KOSCIUSKO COUNTIES WITH DRIZZLE AND SUB
1KFT CEILINGS OBSERVED. CONDITIONS WILL QUICKLY IMPROVE ACROSS THE
AREA FROM NORTHWEST TO SOUTHEAST AS SUBSIDENCE BEHIND THE SHARP
TROUGH AXIS...EVIDENT ON WATER VAPOR CROSSING LAKE MICHIGAN
NOW...USHERS IN MOSTLY CLEAR SKIES OVERNIGHT.

THESE MOSTLY CLEAR SKIES TONIGHT WILL ALLOW TEMPERATURES TO DROP
INTO THE UPPER 30S. HAVE LITTLE CONCERN ABOUT FROST GIVEN SURFACE
WINDS BETWEEN 6 AND 8 KTS OVERNIGHT IN THE WAKE OF THE DEPARTING LOW
PRESSURE SYSTEM.

HIGH PRESSURE WILL KEEP SKIES SUNNY ON FRIDAY WHICH WILL HELP
TEMPERATURES RECOVER FOR A NEAR 25 DEGREE DIURNAL SWING. COLD AIR
ADVECTION WILL CEASE NEAR 12Z AND SOME 850MB WARMING WILL OCCUR IN
OUR WESTERN AREAS AS SUBSIDENCE INCREASES WITH THE APPROACHING
RIDGE. MOST MODEL GUIDANCE FOR TOMORROW IS LOWER THAN CURRENT
FORECAST HIGH TEMPERATURES...BUT ELECTED TO MAKE ONLY MINOR
ADJUSTMENTS TO PREVIOUS FORECAST HIGH TEMPERATURES GIVEN
AFOREMENTIONED FULL SUN AND BUILDING RIDGE.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

QUIET WEATHER TO BEGIN THIS PERIOD AS LOW LEVEL RIDGE AXIS EXTENDS
FROM WESTERN GREAT LAKES INTO THE MID MS RIVER VALLEY. MAIN FORECAST
CHALLENGE FOR THE WEEKEND INTO EARLY NEXT WEEK WILL BE RESOLVING
AMPLITUDE OF MID/UPPER LEVEL RIDGING AND THE POSSIBILITY OF EMBEDDED
CONVECTIVELY ENHANCED VORTICITY MAXIMUM PROGRESSING THROUGH THE MEAN
RIDGE. A GREATER CHANCE OF CONVECTION FOR THE SATURDAY/SUNDAY PERIOD
SHOULD REMAIN TO THE WEST OF THE AREA ACROSS THE MID MS RIVER VALLEY
IN BETTER COLOCATION WITH LOW LEVEL MASS CONVERGENCE ASSOCIATED WITH
LOW LEVEL JET. THICKNESS ORIENTATION/PROPAGATION VECTORS MAY SUPPORT
EAST/SOUTHEAST TRACK OF THIS CONVECTION INTO FAR WEST OR SOUTHWEST
PORTIONS OF THE FORECAST AREA IN THE SATURDAY NIGHT-MONDAY PERIOD.
WILL CONTINUE TO PLAY IT CONSERVATIVELY WITH THIS FORECAST WITH MORE
CREDENCE INTO GEM/EC IDEA OF SLOWER EASTWARD PROGRESSION OF LOW
LEVEL THETAE RIDGE AND SLOWER NORTHWARD WARM FRONTAL PUSH. SOME
CONCERN THAT GFS IS OVERDOING CONVECTIVELY ENHANCED VORTICES GIVEN
RECENT BIASES AND SOMEWHAT OVERDONE LOW LEVEL MOISTURE. THUS...WILL
MAINTAIN JUST SOME SLIGHT CHANCE POPS ACROSS THE FAR WEST/SOUTHWEST
DURING THIS PERIOD. WITH LOCAL AREA IN INFLECTION ZONE OF UPPER
LEVEL PATTERN...LOW LEVEL THERMAL ADVECTIONS WILL REMAIN WEAK
THROUGH THE WEEKEND WITH ONLY A SLOW MODERATING TEMPERATURE TREND
INTO THE LOWER 70S BY MONDAY.

MORE AGGRESSIVE WARM FRONTAL PUSH STILL EXPECTED LATE MONDAY INTO
TUESDAY WITH EC PREFERENCE...AND HIGHS TO AROUND 80 POSSIBLE ONCE
AGAIN BY TUESDAY AFTERNOON. MAINTAINED PREVIOUS CHANCE TSRA POPS FOR
TUESDAY/TUESDAY NIGHT AS WARM FRONT LIFTS NORTH THROUGH THE
AREA...WITH FOCUS FOR ADDITIONAL TSRA CHANCES LIKELY SHIFTING NORTH
OF THE AREA TOWARD MIDWEEK AS CAPPING ISSUES ARISE IN WARM SECTOR.
HAVE KEPT WED/THU DRY AT THIS TIME...ALTHOUGH DEPENDING ON WARM
FRONTAL PROGRESSION MAY EVENTUALLY NEED TO ADD A CHANCE ACROSS THE
NORTH. MEDIUM RANGE MODELS IN GENERAL AGREEMENT ON UPPER RIDGE
AMPLIFICATION TOWARD THE END OF THE PERIOD DOWNSTREAM OF NEXT
AMPLIFIED WESTERN CONUS TROUGH. DID NUDGE CR ALLBLEND HIGHS UP A BIT
FOR WED/THU INTO THE LOWER TO MID 80S. SOUTH/SOUTHWEST NEAR SFC FLOW
TRAJECTORIES SHOULD LIMIT LAKE COOLING TO NORTHERN PORTIONS OF
BERRIEN COUNTY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU MAY 23 2013

IFR CONDITIONS AT SOUTH BEND EXPECTED TO CONTINUE FOR A
COUPLE MORE HOURS BEFORE SUBSIDENCE BEHIND THE APPROACHING SHORTWAVE
IMPROVES FLYING CONDITIONS TO MVFR AND EVENTUALLY VFR. KFWA SHOULD
REMAIN MVFR AS LOWER CIGS HAVE STAYED EAST OF THE TERMINAL THUS FAR.
THERE IS A SMALL CHANCE FOR IFR CIGS TO MOVE INTO THE TERMINAL OVER
THE NEXT FEW HOURS...BUT GIVEN LOW CONFIDENCE...HAVE ELECTED TO OMIT
ANY MENTION IN THE TAF.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...KG
SHORT TERM...BENTLEY
LONG TERM...MARSILI
AVIATION...BENTLEY


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