Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 140926
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
526 AM EDT MON APR 14 2014

.SYNOPSIS...
ISSUED AT 410 AM EDT MON APR 14 2014

GUSTY WINDS AND SHOWERS CAN BE EXPECTED THIS MORNING AS A STRONG
COLD FRONT CONTINUES TO SLOWLY SHIFT EAST INTO THE AREA. RAIN WILL
TAPER IN COVERAGE AND TEMPERATURES WILL FALL INTO THE 40 AND 50S
BEHIND THIS COLD FRONT IN THE AFTERNOON. AN UPPER LEVEL
DISTURBANCE WILL BRING ANOTHER ROUND OF PRECIPITATION TO THE
REGION TONIGHT. PRECIPITATION WILL LIKELY BEGIN AS A MIXTURE OF
RAIN AND SNOW BEFORE CHANGING OVER TO ALL SNOW. SOME LIGHT SNOW
ACCUMULATIONS WILL BE POSSIBLE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM EDT MON APR 14 2014

ACTIVE SHORT TERM PERIOD WITH FOCUS CHANGING FROM
SHOWERY/WINDY/MILD WX THIS MORNING TO COLD AND SNOW TONIGHT.

POTENT LEAD SHORTWAVE AND ATTENDANT NORTHERN IL 995 MB SFC
REFLECTION LIFTING NORTHEAST THROUGH THE GREAT LAKES REGION THIS
MORNING WILL FINALLY FORCE A STRONG FRONTAL BOUNDARY EAST INTO THE
FORECAST AREA TODAY. ENHANCED MOISTURE TRANSPORT ALONG AND JUST
AHEAD OF THIS FRONT VERY IMPRESSIVE (PWATS TO 1.4 INCHES) WITHIN
STRONG 60-70 KT LOW LEVEL JET. THIS AND INCREASED CONVERGENCE
ALONG BOUNDARY SHOULD BE ENOUGH TO KEEP SCATTERED/NUMEROUS SHOWERS
GOING THROUGH AT LEAST MID/LATE MORNING ACROSS MAINLY THE EASTERN
CWA. A LULL IN PRECIP IS EXPECTED BY LATER THIS MORNING AND
AFTERNOON AS DEEPER MOISTURE SHIFTS OFF TO THE EAST AND LARGE
SCALE ASCENT WANES IN WAKE OF VIGOROUS SYSTEM. OTHERWISE...ANOTHER
WINDY DAY WITH STRONG POST FRONTAL CAA ENSURING FALLING TEMPS.

ANOTHER ROUND OF PRECIPITATION WILL LIKELY OVERSPREAD THE REGION
TONIGHT AS A CONSOLIDATING PLAINS UPPER TROUGH AMPLIFIES EAST
INTO THE MS VALLEY AND HELPS IGNITE A RATHER ROBUST MID LEVEL
FGEN/DEFORMATION RESPONSE. THIS RENEWED DEEP ASCENT AND PROGGED
REDUCED STABILITY JUST ABOVE THE FRONTAL SLOPE SHOULD SUPPORT A
VIGOROUS CIRCULATION...WITH A BAND OF PCPN LIKELY FILLING
NORTHEAST INTO OUR INDIANA/MICHIGAN ZONES THIS EVENING...THEN
PIVOTING/ENDING WEST TO EAST OVERNIGHT. PCPN SHOULD BEGIN AS A
RAIN/SNOW MIX (JUST RAIN EAST OF I-69) BUT QUICKLY CHANGE OVER TO
ALL SNOW PER ONGOING/DEEPENING COLD ADVECTION (850 MB TEMPS DROP
TO NEAR -10C) AND STRONG/DEEP ASCENT. OVERNIGHT TIMING AND WHAT
SHOULD BE DECENT PRECIP RATES SUGGEST THAT THERE MAY BE SOME
ACCUMULATION ON MAINLY GRASSY SURFACES (1-2" POSSIBLE
SOUTHERN/EASTERN ZONES...LESS THAN AN INCH NORTHWEST). LOW
PROBABILITY THAT SNOW MAY EVEN COME DOWN HARD ENOUGH FOR A TIME TO
ALLOW SNOW TO STICK TO THE ROADS.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 410 AM EDT MON APR 14 2014

NEAR RECORD COLD TEMPS TUESDAY/TUESDAY NIGHT AND CHANCE OF RAIN ON
FRIDAY ARE THE ONLY SENSIBLE WEATHER ITEMS OF NOTE THIS LONG TERM
PERIOD. MAIN PRECIP SHIELD WILL EXIT THE CWA BY TUESDAY MORNING AS
SHARP MIDLEVEL TROUGH AXIS CROSSES THE AREA. A FEW SCT LAKE EFFECT
SNOW SHOWERS ARE POSSIBLE TUESDAY MORNING AS 850MB TEMPS DROP BELOW
-14C IN STRONG CAA/NORTHWEST FLOW REGIME. TREMENDOUS DRY AIR
ADVECTION WILL LIMIT SNOW POTENTIAL BUT NAM BUFR SOUNDINGS DO
INDICATE A BRIEF PERIOD OF GOOD SUPERSATURATION WITH RESPECT TO ICE
IN THE -10 TO -15C RANGE DURING THE MORNING HOURS. THIS COULD
SUPPORT A FEW FLURRIES BUT DRY AIR ENTRAINMENT WILL LIKELY PREVENT
ANY ACCUMULATION. SECOND HALF OF TUESDAY THROUGH THURSDAY STILL
LOOKING DRY AS MIDLEVEL HEIGHTS STEADILY RISE AHEAD OF NEXT TROUGH
DIGGING INTO THE NORTHERN PLAINS. WARM FRONTOGENESIS AND ASSOCIATED
UPPER JET SUPPORT REMAIN CONFINED WELL TO OUR NORTHWEST THROUGH
THURSDAY. THE STORY CHANGES BY FRIDAY AS PACIFIC JET STREAK/PV
ANOMALY DIG THROUGH THE ROCKIES AND EJECT INTO THE SOUTHERN PLAINS.
THE GRADUAL APPROACH OF THIS WELL-DEFINED...NEGATIVELY TILTED TROUGH
WILL BRING A GOOD CHANCE OF RAIN TO OUR CWA BY FRIDAY. CHANCE OF
LIGHT RAIN MAY ALSO LINGER INTO SATURDAY AS THE WAVE MERGES WITH
NORTH DAKOTA VORT MAX AND BECOMES VERTICALLY STACKED OVER THE GREAT
LAKES.

VERY COLD TEMPS...BY MID APRIL STANDARDS...WILL BE THE MAIN STORY
TUESDAY INTO TUESDAY NIGHT. AFOREMENTIONED THERMAL TROUGH WILL
LIKELY CAP TUESDAY`S HIGHS IN THE UPPER 30S TO LOWER 40S DESPITE
DECREASING CLOUDS DURING THE AFTERNOON. OVERNIGHT TEMPS A BIT TRICKY
AS SOUTHEAST GRADIENT DOES BEGIN TO INCREASE BY EARLY WEDNESDAY
MORNING BUT EXPECTING MOSTLY CLEAR SKIES. BUMPED LOWS A FEW DEGREES
HIGHER IN OUR WESTERN COUNTIES BUT NORTHEAST ZONES COULD STILL FLIRT
WITH UPPER TEENS. MAJORITY OF LATEST RAW AND STATISTICAL GUIDANCE
SUGGEST MOST AREAS WILL BE IN THE LOW TO MID 20S THOUGH AND DID NOT
DEVIATE TOO FAR FROM THAT. GRADUALLY MODERATING TEMPS THEN EXPECTED
THROUGH THE END OF THE WEEK AS SOUTHERLY FLOW INCREASES AHEAD OF
PREVIOUSLY DISCUSSED SYSTEM ARRIVING ON FRIDAY.

RECORD LOWS...
       15TH        16TH
SBN    19 (1928)   22 (1935)
FWA    20 (1907)   24 (1935)

RECORD COLD HIGHS FOR THE 15TH...
SBN    35 (1907)
FWA    37 (1928)

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 526 AM EDT MON APR 14 2014

VIGOROUS SHORTWAVE LIFTING INTO THE GREAT LAKES REGION THIS
MORNING WILL FINALLY FORCE A STRONG FRONTAL BOUNDARY EAST THROUGH
SBN AROUND TAF ISSUANCE AND FWA AROUND MIDDAY. SHOWERS AND
LOWERING CIGS WILL CONTINUE THIS MORNING IN LOW LEVEL THETA-E
RIDGE...WITH MODEST RISE/FALL COUPLET SUPPORTING GUSTS TO AROUND
30 KNOTS. OTHERWISE BREEZY WITH MVFR STRATOCU EXPECTED IN
DEEPENING POST FRONTAL CAA WEDGE LATER THIS MORNING/AFTERNOON.
CANNOT RULE OUT A FEW SHOWERS THIS AFTERNOON AS MID LEVEL
BAROCLINIC ZONE LINGERS OVER NORTHERN INDIANA IN ADVANCE OF A
CONSOLIDATING/AMPLIFYING CENTRAL CONUS UPPER TROUGH...BUT
PROBABILITY/COVERAGE APPEARS TOO LOW FOR A SHRA MENTION. RENEWED
MID LEVEL FGEN/DEFORMATION WITH THIS UPPER TROUGH SHOULD ALLOW
ANOTHER ROUND OF MORE WIDESPREAD PCPN TO OVERSPREAD NORTHERN
INDIANA THIS EVENING INTO THE OVERNIGHT. MODEL THERMAL PROFILES
ACTUALLY FAVOR MAINLY SNOW IN SBN...WITH A RAIN/SNOW MIX CHANGING
OVER TO ALL SNOW IN FWA LATE IN THE EVENING/EARLY OVERNIGHT.

&&

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

&&

$$

SYNOPSIS...MARSILI/STEINWEDEL
SHORT TERM...STEINWEDEL
LONG TERM...AGD
AVIATION...STEINWEDEL


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