Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 311105
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
705 AM EDT TUE MAR 31 2015

.SYNOPSIS...
ISSUED AT 451 AM EDT TUE MAR 31 2015

DRY WEATHER WILL RETURN TODAY AS THE CLIPPER SYSTEM...THAT
BROUGHT SOME LIGHT RAIN TO THE REGION MONDAY NIGHT INTO EARLY
THIS MORNING...MOVES TO THE MID ATLANTIC REGION. TEMPERATURES
WILL BE A BIT COOLER THAN YESTERDAY...BUT SHOULD STILL MAINLY
REACH INTO THE 50S. LOWS TONIGHT WILL DIP BACK INTO THE 30S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 451 AM EDT TUE MAR 31 2015

PRE FIRST PD TO ADDRESS REMAINING LIGHT RAFL CHCS ACRS NERN THIRD
OF CWA PRIOR TO 12 UTC ALONG WITH SIG HIR MID LVL COVERAGE. TWO
SUCCINCT SHORTWAVES ACRS WRN GRTLKS DRIVING CLIPPER SYSTEM THIS
AM. FIRST SHORTWAVE OVR WCNTL LWR MI WITH ASSOCD SFC LOW OVR FAR
SRN LK MI AT 08 UTC. NEXT HIR BELTED MATURE/LYTIC CLIPPER
SITUATED JUST NORTH OF MN ARROWHEAD. SRN CLIPPER QUICKLY SLIDES
ESEWD WITHIN RAPID/GRDL RESURGENT HGHT BLDG MID-TOP FLOW...TO MD
PANHANDLE BY MIDDAY. POSITIONING/DECAY OF NRN SYSTEM TO CONFER
ONLY SHALLOW CAA INTO CWA /INLAND OF DEEP COLD LAKE SHADOW/ AND
HAVE MAINTAINED OPTIMISTIC /MET MOS LARGELY IGNORED/ WRT THERMAL
RECOVERY TODAY. RAP13 LAPSE RATES IN LWST 100 MB STEEPER THAN
YDAY ON ORDER OF 9.5-10C/KM AT PEAK HEATING WITHIN WELL MIXED
BLYR. CAVEAT WILL BE AMOUNT OF COVERAGE/CLOUD BASE HEIGHTS OF
WHAT SHOULD BE WELL GENERATED CU FIELD BY MID/LATE MORNING.
ENTRAINMENT OF DRIER /SPCLY SUBCLOUD LWR THETA-E AIR/ INCRSG WITH
TIME THROUGH THE DAY TO LEND HIR BASES/DCRSD COVERAGE TREND INTO
AFTN/PEAK INSOLATION. SLIGHTEST OF RISE TO OVERNIGHT TEMPS AS 925
MB COLD POOL EXITS INTO LWR GRTLKS...IN LINE WITH MOS/BLENDED
TREND.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 451 AM EDT TUE MAR 31 2015

THE OVERALL UPPER AIR PATTERN THIS PERIOD WILL BEGIN TO SHIFT
WITH A LARGE SCALE TROF EVENTUALLY AMPLIFYING OVER WESTERN NORTH
AMERICA. CHALLENGES THIS PERIOD INCLUDE TIMING OF INDIVIDUAL SHORT
WAVE TROFS MOVING THROUGH THE LONG WAVE PATTERN. THE FIRST OF
THESE SYSTEMS SHOULD REACH THE AREA THURSDAY. HAVE ADDED A CHANCE
FOR THUNDER THURSDAY. THUNDERSTORM PARAMETERS APPEAR MARGINAL
GIVEN LIMITED MOISTURE AND MARGINAL CONVECTIVE AVAILABLE POTENTIAL
ENERGY BETWEEN 500 J/KG AND 1000 J/KG. HOWEVER...UPPER LEVEL JET
SUPPORT AND DYNAMIC LIFT SHOULD BE SUFFICIENT TO ALLOW A CHANCE
FOR THUNDERSTORMS. ENERGY/HELICITY 0/3KM VALUES OF 1.0 TO 1.5 M2S2
SUPPORT AN OUTSIDE CHANCE FOR SUPERCELL STORMS.

A SECOND UPPER TROF WILL BRING A CHANCE FOR SHOWERS FRIDAY
FOLLOWED BY DRY AND SEASONAL TEMPERATURES OVER THE WEEKEND.
TEMPERATURES SHOULD RISE ABOVE NORMAL EARLY NEXT WEEK AS THE
UPPER TROF DEVELOPS OVER WESTERN NORTH AMERICA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 701 AM EDT TUE MAR 31 2015

SIG CHNGS WRT 12 UTC TAFS...ESPCLY FOR KSBN AS INCRSGLY WIDESPREAD
STRATUS DEVELOPMENT IN WAKE OF COLD FRONTAL BNDRY DROPPING SWD
FM WRN MI TO CHICAGOLAND. WL INTRODUCE IFR CIGS AT KSBN BEFORE
CIGS MIXOUT TO FUELING/ALTERNATE CRITERIA BTWN 1330-14 UTC. KFWA
FARTHER REMOVED FM 15-20KT SWD ADVANCE OF STRATUS DECK AND
MAINTAIN PRIOR OPTIMISM WITH ONLY BRIEF HIGH END MVFR PD 14-16
UTC. TWEAKS TO MORE SHARPLY VEERED SFC FLOW WITH ONSET OF ST LYR
FOR KSBN.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MURPHY
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...MURPHY


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