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Area forecast discussion 
National Weather Service northern Indiana
455 am EDT sun Mar 29 2015

issued at 455 am EDT sun Mar 29 2015

A cold frontal system will move through the upper Midwest and
through the region late this afternoon and evening. Ahead of this
system there will be some scattered showers...primarily in the
afternoon and evening and mostly light. It will become windy and
highs will push into the middle 40s. Lows Sunday night will fall
back into the lower 30s.


Short term...(today and tonight)
issued at 452 am EDT sun Mar 29 2015

Rapid progressive northern stream flow with succinct shortwave energy
across Dakotas this am to move into northern Great Lakes by this evening with
strong 160-190m/12hr height falls and associated cold frontal boundary.
However...leading narrow deep layer warm air advection along with lackluster
Theta-E draw /nrn most periphery axis of 0.75 precipitable water struggles to
reach northeastward into northern in this afternoon/ which is further impeded with
time especially with eastward extent given antecedent precipitable water around 0.15 in
eastern County Warning Area this am. High conditions pressure deficits /gte 100 mb at 925 mb at
18 UTC today/ will be slow to relent. Kept probability of precipitation a bit below mav/MOS
given coverage concerns...overall low quantitative precipitation forecast event and possible
split with time /mi focus associated with closer proximity to
hfc/stronger frontal convergence focus and southward shift with time as
northern extension of already feeble moisture axis becomes shunted
along Ohio River valley. While conceptual models might suggest rain v
showers given deep layer warm air advection ascent...have opted for rain showers
wording/relative short duration/pontl pockets of sub cloud
saturation difficulties leading to transient rafl events this
aftn/eve. Am insolation and deep layer warm air advection should allow decent
thermal recovery before thicker late afternoon cloud cover/precipitation
cooling occurs and have raised slightly over prior. Model
soundings/xsctions suggest that with time aftr surface frontal passage
subsidence/drying to bring at least partial clearing by daybreak.
Little change needed to existing timing of exiting probability of precipitation/wx/min temperatures


Long term...(monday through saturday)
issued at 452 am EDT sun Mar 29 2015

The upper level flow will become more high zonal this period with
moderating temperatures. Some challenges this upcoming week
include timing of short wave troughs and associated precipitation.
For early in the week...initially dry conditions with limited
moisture should limit precipitation associated with a weak upper
level trough that is expected to move across the northern fringe of
the area Monday night. Thermal profiles support all rain Monday
night. Kept a small chance for rain over northeast areas Monday

For the rest of the period...uncertainty with timing and strength
of systems increases rapidly after Wednesday. These uncertainties
are reflected in the run to run inconsistencies of the GFS and
European model (ecmwf) as well as significant spreads among ensemble members.
Increasing moisture is likely with temperatures rising above
normal late in the week. Rain chances increase late Wednesday for this package for now with given
uncertainties...went with a chance for showers late Wednesday
night through Friday night.


Aviation...(for the 06z tafs through 06z Sunday night)
issued at 154 am EDT sun Mar 29 2015

Primarily VFR met conds through the period. However...high detail
with regard to strengthening surface wind field through the day ahead
frontal system. Brief period of rain showers potnly followed with high end
MVFR ceilings along with veering/increasingly mixed and less gusty
winds toward end of forecast period. While evening 2kft wrly flow will be appears to be sufficiently mixed/coincident with surface
wind shift to preclude low level wind shear mention.


Iwx watches/warnings/advisories...
Lm...Gale Warning from 11 am this morning to 5 PM EDT this afternoon
for lmz043-046.



short term...Murphy
long term...skipper

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