Scientific Forecaster Discussion
fxus63 kiwx 280611
Area forecast discussion
National Weather Service northern Indiana
111 am EST Tue Feb 28 2017
issued at 1250 am EST Tue Feb 28 2017
Showers and a few storms will spread across the area before
daybreak. A lingering shower or storm is possible today before
activity becomes widespread tonight. Strong to severe
thunderstorms are possible this upcoming night as a strong cold
front approaches. Highs will reach the 60s today, but will be
turning colder later Wednesday into Thursday behind the front with
chances for snow showers lingering through the end of the week.
issued at 855 PM EST Mon Feb 27 2017
Forecast generally on track into the overnight hours. Dry air mass
remains in place with dewpts in the 30s. Band of radar returns
across central Illinois not reaching the ground nor is shower
activity in portions of Missouri. Hi res models all seem to match
with this scenario with rapid uptick on precip after 6z as low
level jet ramps up and surge of higher Theta E air moves rapidly
NE. Elevated showers/isolated thunderstorms still appear on track
and no sig changes to timing or coverage.
Short term...(tonight through Tuesday night)
issued at 300 PM EST Mon Feb 27 2017
Potent upstream SW trough digging through cntrl California attm will swing
through the srn rockies tonight and through the Central Plains
Tue night. Downstream Lee side cyclogenesis will consolidate Tue
aftn across Kansas and then lift northeast through Michigan on Wed. Until
then warm sector will expand greatly with significant low level
thermal troughing building into the srn lakes. Will bump Max temps
higher esp in light of strong mixing Tue aftn. Otherwise lead
buldge of higher Theta-E air on nose of newd advancing low level
jet will lead to shra and perhaps embedded thunder after midnight
Initial Theta-E surge weakens Tue under modest mid level capping.
Lack of background synoptic forcing suggest little of concern until
late aftn west tied to renewed...rapidly increasing low level
mass flux. Of concern is escalation of deep layer flow Tue night
within destabilizing airmass esp srn half and deep tropospheric
ascent that develops within/ahead of prefrontal trough overnight.
Depth of low level Theta-E ridge certainly supportive of potential
severe storms here from late afternoon through early Wed morning
with a damaging wind threat given extreme background low level
flow in place. Nonetheless some significant rainfall may
materialize through the Wabash and Maumee basins and elicit some
minor river flooding given wide open Gomex feed.
Long term...(wednesday through monday)
issued at 300 PM EST Mon Feb 27 2017
Progressive system aloft will pass through the lakes Wed as sfc cold
front sweeps east. Mild morning temps will crash esp west as low
level cold advection wraps in with aftn snow showers far north
pending where mid level deformation zone/moisture plume tracks.
Secondary clipper follows Thu with a period of warm advection snow
followed by a period likely lake enhancement Thu night north half
and secondary cold advection surge into Fri. Thereafter zonal flow
aloft develops before amplifying late weekend. Thus cold temps Fri
will quickly moderate back to well above normal by sun.
Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 111 am EST Tue Feb 28 2017
An initial round of showers and a few storms will spread across
the area early this morning. There will be a break in most of the
showers during the day before much stronger storms move into the
area tonight ahead of a strong cold front. Winds should increase
this evening with the chance for strong to possibly severe storms
to move into the area near the end of the taf period.
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