Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 250753

Area Forecast Discussion
National Weather Service Northern Indiana
353 AM EDT Sun Jun 25 2017

Issued at 345 AM EDT Sun Jun 25 2017

A few light showers or sprinkles will continue early this morning
across southern Lower Michigan, but mainly dry conditions are
expected across the region for most of the day along with
continued below normal temperatures. There is a slight chance of a
shower or thunderstorm across far northern Indiana and southern
Lower Michigan later this afternoon, but most locations will
remain dry. A few showers may persist into this evening, with
another disturbance bringing a chance of showers and thunderstorms
again for Monday. Dry weather is then expected to return later
Monday evening into Tuesday. High temperatures today will range
from 70 to 75 with low temperatures tonight dropping into the low
to mid 50s. High temperatures on Monday will be limited to the
upper 60s to around 70.


.SHORT TERM...(Today through Monday Night)
Issued at 345 AM EDT Sun Jun 25 2017

Previous forecast remains in good shape with focus of the remainder
of the weekend into Monday on the below normal temperatures and
isolated shower/storm potential.

A strong but moisture-starved upper vort max across the western
Great Lakes will be accompanied by a few showers across extreme
northern Indiana/southern Lower Michigan over the next few hours.
Forcing with this wave will eventually shift eastward after
daybreak. Looking upstream, no immediate significant short wave is
evident this morning that will impact the local area today, with
just a sheared vorticity maximum shifting eastward across the
southern Great Lakes this afternoon. With a dry air low level air
mass in place and relatively weak mid level lapse rates, shower
potential still looks quite limited given lack of substantial
upper forcing. Have opted to hold onto the 15 to 20 PoPs across
northern third of the area later this afternoon during peak
heating/weak surface based instability. As was the case last
evening, stronger upper forcing with next upstream wave dropping
out of southern Manitoba should reach the southern Great Lakes
later tonight with a few showers possible. Passage of secondary
cold front this morning will take another few degrees off high
temperatures today, generally in the lower 70s. Steep low level
lapse rates will allow for gusty west winds again today into the
20 to 25 mph range.

Mid/upper levels will continue to cool for Monday with next upper
level short wave of interest dropping southeast out of the
Northern/Central Plains Monday afternoon. Strongest upper level
Q-vector convg signal with this wave starting to look more
favorable across southwest/southern portions of the forecast area
late Monday afternoon into early Monday evening where broad low
level confluence zone should also set up. Steeper mid level lapse
rates Monday should compensate for still meager moisture to
provide some uptick in sfc based instability, and have not made
much change to low chance rain/slight chance thunder PoPs Monday
afternoon. Given recent guidance trends in timing this wave, did
accept model consensus idea of prolonging low PoPs into the early
evening Monday. Coolest temps of the period expected Monday when
highs across the north will likely be limited to the mid-upper 60s
to around 70 south. Record low maximum temperatures for Monday
will likely not be threatened however (65 at KSBN in 1970, and 61
at KFWA in 1928).


.LONG TERM...(Tuesday through Saturday)
Issued at 345 AM EDT Sun Jun 25 2017

Tuesday/Tuesday night will be dry as mid/upper height rises
spread eastward. Low level thermal troughing will linger across
the region however as another Hudson Bay vort should allow for
only slow low level thermal moderation Tuesday. Thermal/moisture
advection becomes stronger for the Wed/Wed night period with
eventual deamplification of central CONUS upper ridge in response
to a series of Pacific short waves. While details will need to be
sorted out/refined in terms of timing and strength of individual
short waves, the Wed night-Fri period is still shaping up as an
active one with increasing deep moisture and a couple of frontal
waves likely impacting the region due to active Pacific short wave
pattern. While timing is still of low confidence, may need to
watch a few periods of strong storm and heavy rain potential Thu-
Fri. Continued temperature moderation is expected for Wed-Thu with
highs back into the lower to mid 80s by Thursday. Some
indications in medium range model consensus that frontal boundary
may be driven far enough south by next weekend to lessen precip
coverage for the holiday weekend, with temps near or slightly
below normal before heat builds back in closer to the 4th of July.


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 116 AM EDT Sun Jun 25 2017

Southern fringe of compact upper level feature will clip the
forecast area over the next couple of hours. A brief period of
gusty winds (in excess of 20 kts) will be possible but too short
in duration to add to TAFs. Can`t rule out a shower as well but
again no addition to TAFs.

Impacts of the stronger wave passing over the central Great Lakes
may be enough for a stray shower this afternoon, but confidence
and expected coverage warrants no inclusion in TAFs.


IN...Beach Hazards Statement through Monday evening for INZ003.

MI...Beach Hazards Statement through Monday evening for MIZ077.

LM...Small Craft Advisory until 8 PM EDT Monday for LMZ043-046.



SHORT TERM...Marsili
LONG TERM...Marsili

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