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Area forecast discussion 
National Weather Service northern Indiana
841 PM EDT Friday Jul 31 2015

Synopsis...
issued at 400 PM EDT Friday Jul 31 2015

Showers and thunderstorms across the southern portions of
the forecast area will diminish this evening. Otherwise...
expect dry conditions to prevail overnight. Lows will be
in the upper 50s and 60s. On Saturday expect mostly sunny
skies through early afternoon...then increasing clouds and a
slight chance of showers and thunderstorms. Highs will range
from the upper 70s near Lake Michigan to the middle 80s inland.

&&

Update...
issued at 801 PM EDT Friday Jul 31 2015

Updated forecast this evening to remove afternoon wording and
remove probability of precipitation...otherwise no changes made to previous forecast.
Northwest gusts should continue to rapidly diminish over the next
hour with boundary decoupling...allowing for good radiational
cooling conditions tonight which should support previous mins from
upper 50s to lower 60s.

&&

Short term...(this evening through saturday)
issued at 400 PM EDT Friday Jul 31 2015

Quiet forecast in store for the immediate short term with dry
weather expected tonight and Saturday morning in the wake of the
frontal passage this afternoon. High pressure centered over Missouri
will shift eastward into western Tennessee by 21z Saturday...which
keeps our County Warning Area on the periphery under continued westerly winds. Flow
aloft remains fairly zonal out of the west-northwest as fairly
stationary 500mb low spins over Hudson Bay. Models once again
conflicting on probability of precipitation Saturday afternoon. A weak shortwave rotating
around the low will approach the area...providing some support for
precipitation. Moisture will once again be advected into the
region...with precipitable waters expected to be similar to today/around 1.3
inches. Instability is forecast to rise into the 1500 j/kg ml cape
range...so thinking isolated showers/T-storms are not out of the
question. However...forcing is not as strong as it was today...so
kept low chance probability of precipitation for now.

Otherwise...gusty onshore winds Saturday will lead to wave heights
of 2 to 3 feet and strong currents along the Berrien County shoreline.
Kept a moderate swim risk for this time period.

&&

Long term...(saturday night through friday)
issued at 400 PM EDT Friday Jul 31 2015

Pesky upper low will continue to meander over the Hudson Bay
region through middle of next week. Central Continental U.S. Ridge to also
build west and north keeping northwest flow over the Great Lakes.
This will result in normal to below normal temperatures for much
of the period along with periodic chances for showers and
thunderstorms with weak embedded short waves and attendant surface
fronts.

Best chances for showers and storms still looks to be Sunday and
Sunday night. Sharp short wave trough will rotate through the lakes
region along with associated surface cold front. Moisture advection
ahead of this wave and decent middle level forcing should allow area of
precipitation to move through the region. Raised probability of precipitation further to
high chance category but stopped short of likely given convective
nature and model issues. Front now looks to be exiting the area on
Monday but secondary short wave could produce some afternoon
convection so allowed low chance probability of precipitation to continue for now Monday
afternoon. Remainder of forecast remains uncertain with models flip
flopping on a stronger wave middle week moving through the Ohio Valley.
Stayed with some low chance probability of precipitation with highest in the south near surface
boundary. Expect additional changes in guidance as they try to
resolve the weak waves within long wave trough and any convectively
induced short waves upstream.

&&

Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 801 PM EDT Friday Jul 31 2015

The threat of showers has ended at terminals as surface front has
cleared to the south. Drier low level air will continue to filter
southward this evening with mainly clear skies expected through
the night. Northwest winds around 10 knots early this evening
should become west around 5 knots after 02z with center of surface
anticyclone drifting across southern Illinois tonight. Low level
winds to back on Saturday as surface high drifts south of the
area...allowing for some return low level warm/moisture advection.
However will keep tafs dry as any shower/thunderstorm activity is
expected to remain very isolated with weak forcing. Modest
gradient should support some westerly gusts into the 15 to 18 knot
range once again on Saturday afternoon.

&&

Iwx watches/warnings/advisories...
in...none.
Michigan...none.
Ohio...none.
Lm...none.
&&

$$

Update...marsili
synopsis...mesoscale discussion
short term...mesoscale discussion
long term...slash
aviation...marsili



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