Area Forecast Discussion
Issued by NWS Northern Indiana

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327
FXUS63 KIWX 050639
AFDIWX

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

.SYNOPSIS...
ISSUED AT 1223 AM EDT THU MAY 5 2016

SHOWERS WILL SPREAD ACROSS THE AREA EARLY THIS MORNING AS A LOW
PRESSURE SYSTEM LINGERS OVER THE REGION. TEMPERATURES WILL REMAIN
IN THE UPPER 30S TO LOW 40S. SHOWERS AND DRIZZLE WILL END THIS
MORNING WITH SKIES BECOMING MOSTLY SUNNY. HIGHS TODAY WILL
GENERALLY BE IN THE LOW TO MID 60S BUT WILL BE COLDER NEAR LAKE
MICHIGAN. WARMER CONDITIONS ON FRIDAY BUT ANOTHER COLD FRONT WILL
ARRIVE ON SATURDAY WITH ANOTHER CHANCE FOR RAIN.

&&

.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 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1240 AM EDT THU MAY 5 2016

THE UPPER LOW WAS COMPLETELY CUT OFF OVER THE AREA...ALTHOUGH A
BAND OF SHOWERS WAS STILL ROTATING AROUND THE LOW OVER LOWER
MICHIGAN INTO INDIANA. CEILINGS WERE GENERALLY 008 TO 014. DRIZZLE
WAS BECOMING MORE WIDESPREAD IN THE VICINITY OF THE LOW...SO
EXPECT FWA WILL REMAIN IFR UNTIL THE SYSTEM DRIFTS SOUTHEAST OUT
OF THE AREA. OTHERWISE...EXPECT SKIES TO CLEAR LATER TODAY WITH
CONDITIONS BECOMING VFR BY NOON. WINDS SHOULD BECOME LIGHT THIS
EVENING.


&&

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

     GALE WARNING UNTIL 5 AM EDT EARLY THIS MORNING FOR LMZ043-046.

&&

$$

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


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