Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 051056
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
656 AM EDT THU MAY 5 2016

.SYNOPSIS...
ISSUED AT 645 AM EDT THU MAY 5 2016

SHOWERS WILL END ACROSS THE AREA EARLY THIS MORNING AS A LOW
PRESSURE SYSTEM MOVES SOUTHEAST OUT OF THE REGION. SKIES SHOULD
START CLEARING LATER IN THE DAY WITH HIGHS IN THE LOW TO MID
60S...EXCEPT COLDER NEAR LAKE MICHIGAN. MILD WEATHER IS EXPECTED
FRIDAY UNDER A SUNNY SKY WITH HIGHS AROUND 70.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 237 AM EDT THU MAY 5 2016

WATER VAPOR IMAGERY DEPICTING MID-LEVEL CLOSED LOW CIRCULATION
WORKING ITS DOWN THRU INDIANA TONIGHT. DRY SLOT WRAPPING INTO THE
CENTER OF THE CIRCULATION HAS MUCH OF THE AREA IN LIGHT TO
MODERATE DRIZZLE WHILE BAND OF PRECIP IN WESTERN CWA ALIGNING WITH
DEFORMATION AXIS AND ALSO BENEFITING FROM LAKE ENHANCEMENT. CLOSED
LOW WILL CONTINUE TO MOVE OFF TO THE SOUTHEAST BRINGING AN END TO
PRECIP AND GRADUALLY CLEARING SKIES AS SUBSIDENCE AND NVA FILL IN
BEHIND IT. SURFACE RIDGE AXIS WILL SHIFT EASTWARD OVER THE REGION
THURSDAY NIGHT AND FORECAST SOUNDINGS INDICATING SURFACE BASED
INVERSION DEVELOPING LEADING TO BOUNDARY LAYER DECOUPLING WHICH
NOW HAS MOS GUIDANCE TRENDING DOWN WITH UPPER 30S AT SOME
LOCATIONS. AN IDEAL SPRING DAY FOR FRIDAY AS SURFACE RIDGE REMAINS
OVER THE AREA AND UPPER RIDGE FOLDS OVER INTO NORTHERN GREAT LAKES
LEADING TO MODEST 60M HEIGHT RISES OVER OUR AREA...ALL OF WHICH
WILL RESULT IN MOSTLY SUNNY SKIES AND LIGHT W/NW WINDS WITH HIGHS
70-75F. CONTINUED FAIR WEATHER FOR FRIDAY NIGHT WITH LOWS 50-55F.

&&

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 237 AM EDT THU MAY 5 2016

STRONG UPPER RIDGE EXTENDING UP THROUGH THE CANADIAN ROCKIES WILL
FLATTEN AND SHIFT EASTWARD INTO THE CENTRAL US PLAINS AS STRONG
NORTHERN STREAM JET DYNAMICS COME ONSHORE IN BRITISH
COLUMBIA...SENDING DOWNSTREAM SHORT WAVE ENERGY INTO THE NORTHERN
GREAT LAKES REGION TO BEGIN THE FORECAST PERIOD. UPPER TROF
DEEPENS AND CLOSES OFF OVER HUDSON BAY AS 100KT UPPER JET ROUNDS
BASE OF THE TROF IN THE GREAT LAKES. SURFACE LOW WILL TRACK ACROSS
SOUTHERN CANADA AND DRAG A COLD FRONT THROUGH THE AREA ON
SATURDAY. FRONT EXPECTED TO BECOME MORE E/W ORIENTED WITH TIME AS
IT MOVES THROUGH THE AREA WHICH IS EXPECTED TO LIMIT MASS
CONVERGENCE ALONG THE BOUNDARY...BUT TIMING COULD FAVOR MODEST
INSTABILITY AHEAD OF THE FRONT WITH 1000-1500J/KG OF CAPE IN SE
CWA SATURDAY AFTERNOON. SYSTEM WILL BE LACKING IN ANY TYPE OF
RETURN FLOW FROM GULF AS SURFACE RIDGING ANCHORS OVER THE
GULF...BUT EASTWARD SURGE OF 850MB THETAE AXIS WILL HAVE ENOUGH
MOISTURE FOR SURFACE BASED PARCELS TO TAP INTO...SO WILL MAINTAIN
CHANCE POPS FOR SH/TSRA. FRONT THEN PUSHES SOUTH INTO THE OHIO
VALLEY SATURDAY NIGHT AND WEAK SURFACE RIDGING WILL PROVIDE FAIR
AND DRY CONDITIONS FOR THE AREA ON SUNDAY. CLOSED LOW OVER THE
FOUR CORNERS WILL LIFT NORTHEAST TO BEGIN NEXT WEEK AND BRING
BOUNDARY BACK NORTH AS A WARM FRONT. OVERRUNNING MOISTURE AHEAD OF
THIS WILL BRING PRECIP CHANCES BACK INTO THE FORECAST AREA AS
EARLY AS SUNDAY NIGHT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 644 AM EDT THU MAY 5 2016

A BAND OF SHOWERS WAS ROTATING AROUND THE UPPER LOW WILL MOVE
SOUTH OF THE AREA EARLY THIS MORNING. AMPLE MOISTURE AND LOW
CLOUDS WILL PERSIST THROUGH MOST OF THE MORNING...ALTHOUGH
CONDITIONS SHOULD BECOME VFR AT SBN BY NOON. SOME DRYING OF THE
LOWER LAYERS AND DAYTIME HEATING SHOULD ALLOW CONDITIONS TO
IMPROVE BY EARLY AFTERNOON...WITH CLEARING SKIES LATE IN THE DAY.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ043-
     046.

&&

$$

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


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