Area forecast discussion
National Weather Service northern Indiana
627 am EDT Wednesday may 22 2013
Synopsis...
issued at 355 am EDT Wednesday may 22 2013
Low pressure over northeast Iowa this morning will move east
across Southern Lower Michigan today and to southern Ontario
tonight. A weak cool front will trail to the south of the low and
move east across southern Michigan... Indiana... and most of Ohio by
Thursday morning... while a second stronger cold front drops south
across the upper Great Lakes. Scattered showers and thunderstorms
are expected along and ahead of the first cool front... while
scattered showers may accompany the second cold front.
&&
Short term...(today and tonight)
issued at 440 am EDT Wednesday may 22 2013
Upper low over southern Minnesota expected to move east-southeast today/tonight and gradually
shear out/merge with northern stream trough dropping south from Hudson
Bay to the upper Great Lakes. Associated broad surface low should move east
from Iowa across Southern Lower Michigan today and into southern Ontario tonight with
an accompanying weak cool front moving east across our County Warning Area.
Combination of weak uvm associated with these features and some
diurnal destabilization expected to result in showers/thunderstorms in the
area... mainly this afternoon. Afternoon cape expected to be 1000-1500j/kg
with 30-35kt 0-6km shear and steep low level lapse rates. This may
allow some of the storms to become severe with damaging winds and
large hail possible this afternoon... particularly over Northwest Ohio where frontal passage
will be later allowing for better opportunity to destabilize.
A stronger cold front associated with the approaching northern stream trough should
drop into southern lm by dawn Thursday. Forcing tonight however should be
weaker as middle/upper level wind field over the area gradually weakens as
upper low shears out. Given this scenario... stayed close to
inherited chance pop grids for tonight.
Highs today generally forecast a few degrees above MOS based on
recent cool bias and mild start to the day. Cool front should
result in a little lower mins tonight... ranging from around 50
near Lake Michigan to around 60 far southeast.
&&
Long term...(thursday through tuesday)
issued at 440 am EDT Wednesday may 22 2013
A secondary upper level trough will move southeast across the western
Great Lakes region Thursday as cooler air spreads southeast. The
upper level support should be sufficient to produce showers...
although there should be a well defined northwest edge/ending of the
precipitation given the subsidence behind the trough. Put some detail
in the grids in this regard Thursday with the best chance for rain
early in the day. Added patchy frost northern areas Thursday night.
Skies should clear with winds becoming light most areas. Otherwise...
kept the rest of the forecast dry. Spectral models providing a range
of handling the short wave energy moving east as the upper level
ridge amplifies over the eastern half of the Continental U.S.. the European model (ecmwf) keep
the entire period dry and appears reasonable with this solution.
&&
Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 626 am EDT Wednesday may 22 2013
An area of rain showers over Indiana ahead of shortwave lifting north-NE around
upper Midwest low is expected to impact the terminals this morning
with MVFR conditions. Predominantly VFR conditions expected this
afternoon but diurnal destabilization and approaching cool front will likely
result in scattered ts with locally lower flying conditions across northern
Indiana later today. There is however still considerable uncertainty
on timing and even occurrence of deep convection over northern Indiana
this afternoon as cloud cover could delay or prevent significant
destabilization. A second cold front will approach the area from the
north late tonight and should result in lowering ceilings/visibilities by
dawn Thursday.
&&
Iwx watches/warnings/advisories...
in...none.
Michigan...none.
Ohio...none.
Lm...gale watch from Thursday afternoon through Thursday evening for
lmz043-046.
&&
$$
Synopsis...jt
short term...jt
long term...skipper
aviation...jt
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