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Area forecast discussion 
National Weather Service northern Indiana
1035 am EDT Tuesday Sep 16 2014

issued at 1032 am EDT Tuesday Sep 16 2014

Clouds will be on the decrease this afternoon as a ridge of high
pressure settles into the region from the west. The cold front that
passed through last evening will keep below normal temperatures
over the area through Friday. Warmer conditions to near seasonable
normals are expected for the weekend. High temperatures today will
reach into the lower and middle 60s. Low temperatures tonight will
drop back into the lower to middle 40s.


Short term...(today and tonight)
issued at 425 am EDT Tuesday Sep 16 2014

Low level dry air advection will continue to spread from northwest
to southeast across the area this morning. Some breaks in stratus
have developed over past several hours and should continue to see
gradual reduction of stratus as the drier low level air advects
southeast. Where more substantial clearing takes place over the next
few hours...concern for some localized patchy dense fog will persist
until shortly after daybreak.

Otherwise quiet conditions in store for today and tonight with
stratus/stratocu evolution still the primary forecast concern.
Aforementioned dry air advection should provide for lesser cloud
coverage compared to the past few days although patchy low clouds
may tend to persist into middle morning in vicinity of Lake Michigan
across far Northwest Indiana/SW lower Michigan. Perhaps the best potential
for diurnally enhanced stratocu will be just downwind of Lake
Michigan where some very weak low level convergence is possible that
could provide just some slight pooling of moisture and more favored
area of low cloud formation. All in all...not expecting low clouds
to have much of an impact of temperatures by this afternoon with
mixing of 900 hpa thermal forecasts to the surface supporting previous
forecast highs generally in the lower to middle 60s most locations.
Radiational cooling tonight should allow for mins to drop back into
the lower to middle 40s.


Long term...(wednesday through monday)
issued at 425 am EDT Tuesday Sep 16 2014

Upper level minor ridging later this week will allow temperatures to
modify as the upper trough lifts northeast...with readings rising above
normal Saturday ahead of a cold front. The best chance for showers
and possible thunder continues to be Saturday night into early
Sunday. Retained a slight chance for thunder Saturday night. Deep
moisture is lacking and potential convective energy is also lacking
with a wind profile consisting of a unidirectional flow. For early
next week...upstream teleconnections support the redevelopment of
the longwave trough over the eastern Continental U.S....with the trough axis east
of Hudson Bay extending south into the eastern Continental U.S.. the GFS/European model (ecmwf)
and Canadian Gem and ensemble members support this solution...with
very chilly air arriving again early next week. Canadian Gem
ensemble members favor lows well down into the 40s early next
week...including Monday night. GFS and European model (ecmwf) 850 mb forecast
temperatures of near 0c suggest a frost potential starting Monday


Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 637 am EDT Tuesday Sep 16 2014

Low level dry air advection in the wake of surface trough which passed
through the area last evening should continue to gradually erode
stratus deck across northern Indiana this morning. Some diurnal
stratocu redevelopment is expected later this morning/early
afternoon given steep low level lapse rates and residual low
level moisture. If ceilings are realized with diurnal stratocu
today...expecting bases would be at VFR levels after 15 or 16z. In
the meantime...partial clearing has allowed for some patchy fog to
form across the area and may need to include at least MVFR visibilities
restrictions through 13z this morning. Low level anticyclone to
settle across the region tonight providing light and variable
winds and mainly clear skies.


Iwx watches/warnings/advisories...


Synopsis...mesoscale discussion
short term...marsili
long term...skipper

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