Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 170520

Area Forecast Discussion
National Weather Service Northern Indiana
120 AM EDT Thu Oct 17 2019

Issued at 810 PM EDT Wed Oct 16 2019

Winds will slowly subside through the remainder of the evening
and overnight hours, with low temperatures expected to drop into
the upper 30s to lower 40s. Isolated to scattered lake effect rain
showers will also diminish in coverage tonight. Mainly dry
weather is expected for Thursday and Friday, but there will be
another chance of showers Saturday. High temperatures on Thursday
will be in the low to mid 50s, warming to the mid 50s to lower 60s
for Friday.


.SHORT TERM...(This Evening through Thursday)
Issued at 228 PM EDT Wed Oct 16 2019

Regional radar depicting lake effect showers in full swing as
deep cyclonic flow on backside of surface low continues over the
region. Gusty NW winds this afternoon will continue overnight in
presence of strong surface gradient and CAA in low levels. Surface
low continues to lift off to the northeast but NW flow expected
to continue through much of the short term as surface ridging is
slow to build eastward into the region. Thermal trough axis
shifting east and drying in low levels should diminish lake effect
showers overnight but all members of HREF still showing weak
returns over the area into Thursday. Winds and cloud cover should
keep lows near 40F tonight with continued below normal Thursday
with highs only in the lower 50s.


.LONG TERM...(Thursday Night through Wednesday)
Issued at 228 PM EDT Wed Oct 16 2019

Forecast period to begin with transition from cyclonic flow from
departing surface low to ridging building into the region
providing a period of quiet weather for the area. Weakening
surface gradient and clearing skies will bring frost potential to
the area early morning Friday as temps drop into the low 30s.
Plenty of sunshine and developing return flow on Friday will have
temps quickly rebounding into the upper 50s to near 60F. Warming
trend continues through the weekend with temps reaching 65-70F.
Weak frontal boundary passing through Saturday night will be
lacking in both forcing and moisture and carry just a small chance
for a shower. Strong jet dynamics coming onshore in the Pacific
NW this weekend will lead to significant system developing in the
plains and ejecting toward the great lakes beginning of next week.
Closed upper low will lift out of the plains into SW Ontario by
Monday night. Deep surface low associated with this system will be
positioned over Lake Superior and have good gulf return flow
streaming ahead of approaching cold front with ensemble means
currently over an inch QPF. Quasi-zonal flow and weak surface
ridging behind this system will bring dry weather and seasonal
temps to end the forecast period.


.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 120 AM EDT Thu Oct 17 2019

Cool northwest flow will continue to support SCT-BKN lake effect
stratocu through much of this period. Expect ceilings to remain
generally VFR...but brief periods of high-end MVFR will be
possible. The best chance for this will be during the late morning
as a weak shortwave rotates through the area with a slight veering
of low level flow and some minor moisture convergence. Diurnal
heating will tend to raise ceilings by afternoon though and most
guidance is hovering right around 3 kft for the late morning
period. Have therefore introduced a TEMPO group with prevailing
VFR for the rest of the period. Clouds will gradually scatter
Thursday night.


LM...Small Craft Advisory until 4 PM EDT this afternoon for LMZ043-




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