Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 130757
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
357 AM EDT SUN APR 13 2014

.SYNOPSIS...
ISSUED AT 357 AM EDT SUN APR 13 2014

WARM CONDITIONS WILL CONTINUE TODAY AS HIGHS ONCE AGAIN REACH THE
70S. THERE IS A CHANCE FOR SCATTERED THUNDERSTORMS LATER TODAY
ACROSS NORTHWEST INDIANA AND SOUTHWEST LOWER MICHIGAN ALONG A
SINKING FRONTAL BOUNDARY. THIS FRONTAL BOUNDARY AND STRONG UPPER
LEVEL DISTURBANCE WILL INCREASE THE CHANCES OF RAIN AND SCATTERED
THUNDERSTORMS ACROSS THE REGION SUNDAY NIGHT INTO MONDAY.
CONDITIONS WILL TURN COOLER AND BLUSTERY EARLY NEXT WEEK IN THE
WAKE OF THIS FRONTAL SYSTEM.

&&

.SHORT TERM...(TODAY)
ISSUED AT 357 AM EDT SUN APR 13 2014

ANOTHER MILD/DRY DAY IS IN STORE FOR MOST LOCATIONS AS CAPPED WARM
SECTOR DEEPENS IN ADVANCE OF AN AMPLIFYING INTERMOUNTAIN WEST/PLAINS
UPPER TROUGH. THE ONLY REAL THREAT FOR ANY PCPN AND SLIGHTLY COOLER
TEMPS WILL BE ACROSS OUR SW LOWER MI AND FAR NW IN ZONES...WITH THE
MAIN FOCUS THIS MORNING ON THE EVOLUTION OF A WEAKENING SRN WI-NRN
IL CONVECTIVE COMPLEX (AS OF 07Z). STEERING FLOW, RADAR TRENDS,
SHORT TERM GUIDANCE, AND CAPPING ALL SUGGEST THAT BULK OF RAIN
SHOULD PASS NORTHWEST OF THE LOCAL AREA. WITH THAT SAID DID OPT TO
RETAIN SLIGHT CHC POPS IN THE FAR NORTH AS SHALLOW OUTFLOW WORKS
SOUTHEAST INTO THIS AREA LATER THIS MORNING. STRONG MOISTURE FLUX
WITH RENEWED RAMPING OF LLJ AS MAIN CORRIDOR OF HEIGHT FALLS
EJECTS NORTHEAST INTO THE MISSOURI VALLEY WILL ALLOW COVERAGE OF
RAIN/STORMS TO BLOSSOM INVOF BAROCLINIC ZONE/MOISTURE CHANNEL THIS
AFTERNOON JUST WEST OF THE IWX CWA (AGAIN). HOWEVER...SCATTERED
CONVECTION MAY FIRE IN THE NORTHWEST BY MID/LATE AFTERNOON NEAR
LEFTOVER SFC/LAKE BOUNDARY AS SFC HEATING AND COOLING/HEIGHT FALLS
ALOFT LIKELY ENOUGH TO BREAK THROUGH CAP. EXPECT ANY STORMS TO
MAINLY REMAIN BELOW SEVERE LIMITS (VERY LOW RISK FOR MARGINAL HAIL
AND DAMAGING WINDS) IN PROGGED LOW CAPE/MODERATE SHEAR ENVIRONMENT
LATE IN THE DAY/EARLY EVENING. OTHERWISE...WELL MIXED BOUNDARY
LAYER TO NEAR 800 MB IN SW FLOW SHOULD ONCE AGAIN SUPPORT HIGHS
WELL INTO THE 70S AND GUSTY WINDS.

&&

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 357 AM EDT SUN APR 13 2014

CONSOLIDATED MID/UPPER LEVEL TROUGH AXIS WILL FINALLY BEGIN TO MAKE
SOME APPRECIABLE EASTWARD HEADWAY TONIGHT INTO TOMORROW AS 100+ KT
JET STREAK ROUNDS THE BASE OF THE TROUGH AND BEGINS TO LIFT
NORTHEAST. SHARP BAROCLINIC ZONE ASSOCIATED WITH THIS HIGH
AMPLITUDE/SHORT WAVELENGTH TROUGH WILL SLOWLY PUSH EASTWARD THROUGH
THE CWA BY EARLY TOMORROW MORNING AS A DECENT VORTICITY SHRED LIFTS
NORTHEAST AND AIDS WEAK SURFACE WAVE DEVELOPMENT. STEADILY
TIGHTENING 925-850MB THERMAL GRADIENT IN RIGHT ENTRANCE REGION OF
EASTERN CANADA UPPER LEVEL JET STREAK WILL BE FURTHER SUPPORTED BY
THIS APPROACHING WAVE. MEANWHILE...ASSOCIATED INCREASE IN LLJ...TO
OVER 60 KTS AT 850MB...WILL CONTINUE TO ADVECT A HIGH THETA-E
AIRMASS INTO THE REGION WITH PW VALUES CLIMBING TO AROUND 1.4
INCHES. THIS IS NEAR THE 99TH PERCENTILE FOR KDTX AND KILX PW
CLIMATOLOGIES. SURFACE BASED INSTABILITY WILL GRADUALLY WANE THROUGH
THE NIGHT BUT STILL EXPECT A FEW HUNDRED J/KG OF LOW DENSITY CAPE TO
AID THE SENSIBLE WEATHER RESPONSE TO ALREADY FORMIDABLE SYNOPTIC
FORCING. DESPITE STRONG WINDS ONLY A FEW THOUSAND FEET OFF THE
SURFACE....THIS VERY MARGINAL/"SKINNY" CAPE JUST AHEAD OF THE FRONT
FAVORS WEAK UPDRAFTS AND LOW SEVERE WEATHER THREAT...IN LINE WITH
LATEST SPC SWODY1. STILL CERTAINLY A THREAT FOR BRIEF HEAVY RAIN
THOUGH...GIVEN HIGH MOISTURE CONTENT...STRONG SYNOPTIC FORCING...AND
WEAK INSTABILITY/MOIST ADIABATIC LAPSE RATES. MOST LOCATIONS WILL
PROBABLY MEASURE AROUND 0.5 INCHES BY TOMORROW AFTERNOON BUT
EMBEDDED THUNDERSTORMS COULD PUSH SOME ISOLATED AREAS OVER ONE INCH.
THIS MAY CAUSE MINOR PONDING IN LOW LYING AREAS ALONG WITH RISING
RIVER LEVELS BUT MOST OF OUR RIVERS HAVE RECEDED FROM RECENT HEAVY
RAINS ON THE 3RD AND 7TH. THEREFORE NOT EXPECTING A WIDESPREAD FLOOD
THREAT.

PRECIP WINDS DOWN MONDAY AFTERNOON BUT ONLY TEMPORARILY. MAIN TROUGH
AXIS WILL NOT PASS UNTIL TUESDAY MORNING AND LATEST 00Z MODELS
CONTINUE TO SUGGEST ANOTHER ROUND OF CVA AND MIDLEVEL
DEFORMATION/FGEN THAT WILL SPREAD PRECIP BACK INTO THE AREA MONDAY
NIGHT. QPF AMOUNTS WILL BE GENERALLY LIGHT WITH THE BEST DEEP LAYER
MOISTURE BEING SHUNTED EASTWARD BUT PRECIP TYPES DO BECOME AN ISSUE.
STRONG CAA WILL GRADUALLY FORCE TEMPERATURES AT THE SURFACE AND
ALOFT BELOW 0C...WITH SOME BRIEF WET SNOW POSSIBLE. NOT EXPECTING
MUCH ACCUMULATION GIVEN VERY WARM/WET GROUND CONDITIONS AND LIMITED
MOISTURE/FORCING BUT AMOUNTS UP TO AN INCH MAY BE POSSIBLE ON SOME
ELEVATED OR GRASSY SURFACES. EXACT AMOUNTS ARE DIFFICULT TO NAIL
DOWN AS THE BEST CHANCE FOR HIGHER QPF WILL BE IN OUR EASTERN
COUNTIES BUT THOSE AREAS WILL ALSO SEE THE LATEST SWITCH TO SNOW.
TRANSITORY SLEET WILL ALSO BE POSSIBLE AS COLDER AIR FUNNELS IN BUT
EXPECTED BREVITY AND LIMITED IMPACTS PRECLUDE MENTIONING IN THE
FORECAST AT THIS TIME. TROUGH AXIS FINALLY PASSES TUESDAY MORNING
AND DRY WEATHER RETURNS THROUGH THURSDAY AS MIDLEVEL RIDGE FOLDS
EAST.

TEMPS WILL BE ON A DOWNWARD SPIRAL BEGINNING EARLY TOMORROW MORNING.
LATEST HIGHER RESOLUTION MODELS SUGGEST COLD FRONT WILL JUST BE
ENTERING OUR NORTHWEST CWA AROUND 12Z MONDAY. CALENDAR DAY HIGHS FOR
MOST LOCATIONS WILL PROBABLY BE MET DURING THE EARLY MORNING WITH
AFTERNOON TEMPS FALLING INTO THE UPPER 30S AND 40S BEFORE DROPPING
TO THE UPPER 20S MONDAY NIGHT. TUESDAY`S HIGHS STILL LOOK CAPPED
AROUND 40F GIVEN 850MB TEMPS AT OR BELOW -10C. SKIES WILL GRADUALLY
CLEAR BY LATE AFTERNOON BUT EXPECT A FAIR AMOUNT OF STRATOCU IN
STRONG CAA REGIME. TEMPS GRADUALLY MODERATE THROUGH THE REST OF THE
WEEK BUT ANOTHER COLD AIR INTRUSION POSSIBLE AFTER NEXT
TROUGH/SURFACE LOW SLATED TO ARRIVE ON FRIDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1244 AM EDT SUN APR 13 2014

VFR CONDITIONS WILL LIKELY PERSIST THROUGH MOST OF THE TAF PERIOD
AS NORTHERN INDIANA REMAINS IN WARM SECTOR. PARTIAL DECOUPLING HAS
ALLOWED WINDS TO DIMINISH TO LESS THAN 10 KNOTS IN MANY LOCATIONS
AS OF 04Z...BUT SHOULD SEE SOUTHERLY WINDS INCREASE AGAIN LATER
THIS MORNING/AFTERNOON AS DEEP DIURNAL MIXING COMMENCES AND LOW
LEVEL FLOW INCREASES IN RESPONSE TO UPSTREAM HEIGHT FALLS. LOW
CHANCE REMAINS FOR SOME CONVECTION TO CLIP SBN LATER THIS
AFTERNOON/EVENING AS WEAK INSTABILITY BUILDS AND LOWER AMPLITUDE
(CONVECTIVELY ENHANCED) SHORTWAVE ENERGY POSSIBLY DETACHES
CONVECTION SOUTH INTO WARM SECTOR. MUCH BETTER CHANCES FOR
RAIN/RESTRICTIONS WILL CONTINUE TO RESIDE NORTH AND WEST OF THE
TAF SITES ALONG A WELL DEFINED FRONTAL BOUNDARY THAT WILL FINALLY
WORK INTO AREA LATER TONIGHT.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
     LMZ046.

&&

$$

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


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