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Area forecast discussion 
National Weather Service northern Indiana
732 PM EDT Tuesday Jul 22 2014

issued at 727 PM EDT Tuesday Jul 22 2014

A cold front will move across the region overnight into Wednesday
morning. Scattered showers and thunderstorms are possible along the
front as it passes through the area. Cooler and drier air will
filter in behind the front for Wednesday through the end of the
week. Lows tonight will be in the middle 60s to around 70 degrees with
highs on Wednesday in the 70s.


Short term...(this evening through wednesday)
issued at 306 PM EDT Tuesday Jul 22 2014

Regional radars showing ongoing convection continues to move across
far northern Great Lakes/southern Canada with surface low while
earlier mesoscale convective system dissipating over the middle Mississippi Valley with new
cells starting to form over Iowa this afternoon. Water vapor imagery
and latest RUC analysis shows short wave trough moving across Lake
Superior with upper jet well to the north over the Hudson Bay. This
detachment of upper forcing will be problematic for convection
maintaining along the cold front as it moves through overnight. Best
chances appear to be in the northwest County Warning Area as decent mass convergence along
cold front will combine with modest elevated instability...convective available potential energy
around 1500j/ if convection in Iowa is able to become more
organized it may have enough support to maintain convective
complex...however forming right along thickness ridge will have some
uncertainty in its forward propagation. Front expected to push
through much of the County Warning Area by Wednesday morning with just lingering
chances in the far southeast County Warning Area...trending toward a dry forecast for the
entire area by afternoon. Warm and muggy conditions expected tonight
for the southeast half with lows around 70 while frontal passage will allow
temperatures to drop into the middle 60s northwest. Cooler and less humid for
Wednesday with highs 75-80.


Long term...(wednesday night through tuesday)
issued at 306 PM EDT Tuesday Jul 22 2014

Comfortable/fair weather will prevail Wednesday night through Friday
morning as stable Canadian high pressure drops through. Middle-upper
level flow will briefly transition to a flatter/semi-zonal west-northwest
regime by late Friday into Saturday...while in the low levels winds
veer more southerly allowing an active warm front to work east-northeast into
the region. Lead/weak shortwave in advance of primary shortwave
trough and increasing mass/moisture convergence along the developing
front support inherited chance probability of precipitation for showers/storms during this
time...mainly later Friday night into Saturday.

Re-amplification of eastern Continental U.S. Trough remains a consistent signal
in model guidance Sunday into early next week. Cold front on leading
edge of height falls may support another round of convection later
Saturday night-Sunday depending on timing. Unseasonably cool and
mainly dry weather likely returns early next week.


Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 727 PM EDT Tuesday Jul 22 2014

Challenge overnight is if convection will fire along approaching
cold front and if widespread it will be. Latest satellite
and radar composites showing line trying to develop over Central
Lake Michigan into Wisconsin with an area of showers further south
across Illinois. Will keep previous idea of tafs intact but did add a
thunderstorms in the vicinity to ksbn given latest hires guidance handling of current
weather with indication of further development along boundary.
Questions remain on whether any activity will reach kfwa and impact
operations. Have kept MVFR ceiling there with stratocu development
along front but opted to keep precipitation out of forecast until we see
how development occurs next few hours. VFR Wednesday Post frontal
with northwest winds in the 10 to 15 knot range.


Iwx watches/warnings/advisories...
in...beach hazards statement from 3 am CDT Wednesday through Thursday
morning for inz003.

Michigan...Beach hazards statement from 4 am EDT Wednesday through Thursday
morning for miz077.

Lm...Small Craft Advisory from 4 am Wednesday to 8 am EDT Thursday
for lmz043-046.



short term...Jal
long term...steinwedel

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