Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 130807

Area Forecast Discussion
National Weather Service Northern Indiana
407 AM EDT Sun Aug 13 2017

Issued at 357 AM EDT Sun Aug 13 2017

High pressure over the Midwest will move slowly east over the next
couple of days providing fair weather. Generally dry weather will
continue into Tuesday, however, a weak frontal boundary will move
south across Michigan and into Indiana and Ohio by Tuesday which
could cause an isolated shower in our area. There is a good chance
of showers and thunderstorms Wednesday and Thursday as a low
pressure system moves northeast from the Plains across the Great
Lakes. High pressure will build in behind this system providing fair
weather Friday. Temperatures will remain a bit below normal today,
but should be at or slightly above normal during the work week with
highs in the 80s and lows in the 60s.


.SHORT TERM...(Today and Tonight)
Issued at 357 AM EDT Sun Aug 13 2017

High pressure will move across the area today providing mostly sunny
skies. Wk gradient but strong insolation should provide sufficient
mixing to allow temps to recover from early morning lows in the
lower 50s to afternoon highs near 80. As the high pressure system
moves east of our area tonight, wk waa may sustain patchy
cu/strato cu overnight as light return flow develops. Temps will
not be as cool as this morning with lows in the mid-upr 50s.


.LONG TERM...(Monday through Saturday)
Issued at 357 AM EDT Sun Aug 13 2017

Upr low over ND expected to transition to an open shrtwv as it
moves east into grtlks and srn periphery of circulation
associated with deep upr low over nrn Quebec. This system will
provide some weak forcing across our area as it moves through the
wrn grtlks on Monday. GFS has been fairly consistent for last few
runs on suggesting potential for isolated showers Monday. However,
given expected wk instability/forcing leaned toward NAM/ECMWF and
kept fcst dry. Combination of this shrtwv movg across the grtlks
and another shrtwv dropping se down backside of nrn Quebec low
will cause a wk backdoor front to drop slowly south across MI and
into IN/OH. Although instability should increase as some moisture
pooling occurs along the boundary, it still should be weak at best
(less than 1000j/kg) and expect only an isolated shower at most
in our area.

Shrtwv off the Pacific NW coast movg east along srn periphery of an
upr low off nrn BC coast this morning will move across the Plains
Wed and lift ne across the upr Grtlks Thu. This will strengthen the
lingering sfc boundary over our area Wed and cause it to lift ne
as a warm front and bring a better chc for deep convection.
Likewise, a good chc of thunderstorms Thu as the cdfnt associated
with this system moves through. Dry and a bit cooler wx expected
Fri as high pressure builds in behind this system. As the high
moves east Sat, low level waa/return flow and wk shrtwv movg
through broadly cyclonic mid level flow beneath central Canada
closed low may cause showers to move back into the area. Temps
through the work week should be at or a bit above normal with
highs generally in the 80s and lows in the 60s.


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1224 AM EDT Sun Aug 13 2017

Some patchy ground fog is likely by daybreak. Kept the mention of
3SM BR at Ft Wayne, but limited the duration according to
conditional climatology. The fog will mix out rather quickly with
VFR conditions prevailing.

Otherwise VFR conditions prevail.





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