Special Weather Statement, NWS Northern Indiana

Area Forecast Discussion
National Weather Service Northern Indiana
100 PM EDT Tue Sep 14 2021

.SYNOPSIS...
Issued at 400 AM EDT Tue Sep 14 2021

Thunderstorms are likely late this afternoon into tonight as a cold
front approaches. These storms can be severe with the primary
threat of damaging wind gusts. Large hail and heavy downpours are
also possible. Rain chances will diminish from northwest to
southeast later this evening into the overnight. Cooler and less
humid conditions settle in for Wednesday and Thursday.

&&

.UPDATE...
Issued at 1113 AM EDT Tue Sep 14 2021

The severe weather forecast remains on track at this time. The
overall hazards have not changed. The one piece of uncertainty is
the time and location of storm initiation. Since yesterday
evening's forecast model runs, the trend has been for the forecast
initiation to occur farther east. This trend continues today, but
the possibility of storms developing near KSBN remains within the
realm of possibility. As tempting as it is to create a tight POP
gradient in this area, I'll sit tight for now but I did delay the
timing by 1-2 hours.

CAMS are initializing well this morning; The placement of the
cold front and current T/Td (within about 2 degrees). This helps
maintain forecast confidence. Plenty of CAPE is forecast this
afternoon, but I have noted that wind shear is maximized along the
front at 30kts or greater. I mention this because this could leave
pre-frontal storms a little disorganized in an environment of 20
knots of bulk shear.

&&

.SHORT TERM...(Today and Tonight)
Issued at 400 AM EDT Tue Sep 14 2021

Severe weather potential this afternoon and especially this evening
will continue to be the primary short term weather concern.

In the near term, surface front has crept northward of the local
area across southern Lower Michigan, and this warm front will
continue to lift northward this morning as a strong upper level
short wave trough across Iowa/southern Minnesota lifts northeast
across the western Great Lakes. A reinforced warm sector will
build northward this morning in response, with a more uniform
temperature distribution via good mixing expected today with highs
in the mid to upper 80s (possibly around 90/low 90s in spots).
Southwest winds will increase sharply later this morning, with
gusts into the 25 to 35 mph later this morning into the afternoon.

The combination of the Iowa short wave lifting northeast and a
broader reinforcing upper level trough shifting east from the
Northern Plains will allow sfc cold front boundary to extend from
northern Lower Michigan south-southwest into northeast Illinois
by late this afternoon. The combination of the western Great Lakes
trough slightly suppressing the mid level thermal ridge and
moisture advection/moisture pooling along and just ahead of the
front) should erode the capping issues we have dealt with the past
few days, particularly across northwest half of the area this
afternoon. A mid level jet streak (40-50 knot 700-500 mb flow
sampled in Omaha, NE RAOB last evening) will also lift northeast
across the western Great Lakes.

The best juxtaposition of shear and instability parameters still
appears to reside from far NW Indiana into south central Lower
Michigan late this afternoon/early this evening along pooled
instability axis and on southern periphery of stronger Great
Lakes shear profiles. Multicell mode is expected along and just in
advance of the front late this afternoon, although shear largely
parallel to low level boundary should tend to promote cell mergers
this evening and potential of some smaller line segments capable
of a wind threat. Isolated large hail will also be possible,
particularly in the late afternoon/very early evening hours when
steepest mid level lapse rates will be in place with peak mixed
layer instability on the order of 2000-2500 J/kg. Despite
relatively warm mid levels and high freezing levels, mid level
theta-e minimum should promote some cooler wet bulb zero heights
in the 10.5-11k ft range for a window of isolated large hail
potential late afternoon/early evening. Window of greatest
isolated-scattered severe threat should be relatively narrow
(22Z-03Z) given decent progression of cold front in the evening
and slightly lagging better shear profiles. Main tweak to this
forecast was for a slightly quicker diminishment in PoPs from west
to east this evening.

Pooled moisture and potential of some brief training this evening
could lead to some instances of minor flooding/ponding of water on
roadways, but feel that overall progression of forcing later in the
evening and dry antecedent conditions should preclude higher end
hydro concerns.

&&

.LONG TERM...(Wednesday through Monday)
Issued at 400 AM EDT Tue Sep 14 2021

Other minor tweak to previous forecast was for a slightly faster
timing of the front impacting precip chances into Wednesday. Bulk of
area now looking dry for Wednesday with possible exception across
the southeast third of the area as frontal boundary should show some
slower progression very late tonight into Wednesday. Have maintained
a dry forecast into Thursday as elongated low level ridge axis
persists from the eastern Great Lakes to the Lower MS Valley. Some
low level moisture may try to creep northward again on Thursday
as low level ridge begins to break down, but PoPs below
mentionable thresholds still seem appropriate. Did maintain
consensus guidance 20 PoPs on Friday as fast moving northern
stream wave could send weak sfc trough into southern Great Lakes,
but confidence continues to diminish in measurable precip on
Friday.

Major theme of the remainder of the forecast will be the trend back
to much above normal temperatures for the weekend as large scale mid
level height rises and amplification of longwave pattern commence.
Amplification of this pattern could lead to some increased precip
chances toward the end of this forecast valid period for the
middle of next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 100 PM EDT Tue Sep 14 2021

Low pressure centered over Lake Superior with cold front trailing
down Lake Michigan and back into northern Illinois will bring
scattered showers/thunderstorms to the area this evening/tonight.
Latest HREF guidance has members lacking in coverage along the
front initially as it moves through KSBN and will therefore cover
with VCTS mention for now. Line then becomes more organized as it
approaches and moves through KFWA...will use SHRA for prevailing
and tempo group for TSRA. Latest NBM guidance still indicating
predominately VFR for ceilings as KFWA less than 30 percent chance
for MVFR. Some indication of MVFR/IFR conditions developing in
post-frontal environment by early Wednesday morning but timing
looks to be southeast of KFWA by then...will continue to monitor
for later issuances. Gusty southwest winds continuing to begin
this TAF cycle then becoming light northwest tonight behind the
front.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Beach Hazards Statement from 5 PM CDT this afternoon through
     late tonight for INZ003.

MI...Beach Hazards Statement from 6 PM EDT this evening through late
     tonight for MIZ077.

OH...NONE.
LM...Small Craft Advisory until 5 AM EDT Wednesday for LMZ043-046.

&&

UPDATE...Brown
SYNOPSIS...Marsili
SHORT TERM...Marsili
LONG TERM...Marsili
AVIATION...JAL

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Hazardous Weather Outlook
National Weather Service Northern Indiana
509 AM EDT Tue Sep 14 2021

INZ004>009-012>018-020-022>027-032>034-MIZ078>081-OHZ001-002-004-005-
015-016-024-025-150915-
St. Joseph IN-Elkhart-Lagrange-Steuben-Noble-De Kalb-Starke-Pulaski-
Marshall-Fulton IN-Kosciusko-Whitley-Allen IN-White-Cass IN-Miami-
Wabash-Huntington-Wells-Adams-Grant-Blackford-Jay-Cass MI-
St. Joseph MI-Branch-Hillsdale-Williams-Fulton OH-Defiance-Henry-
Paulding-Putnam-Van Wert-Allen OH-
509 AM EDT Tue Sep 14 2021 /409 AM CDT Tue Sep 14 2021/

This Hazardous Weather Outlook is for northern Indiana, southwest
Michigan and northwest Ohio.

.DAY ONE...Today and tonight.

Thunderstorms are likely late this afternoon into this evening.
Some storms could be strong to severe late this afternoon and this
evening. The greatest potential threat is isolated to scattered
damaging wind gusts. Isolated large hail and torrential downpours
are also possible. The threat of severe weather will diminish after
midnight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

The probability of widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed late this afternoon and tonight.

INZ003-MIZ077-150915-
La Porte-Berrien-
509 AM EDT Tue Sep 14 2021 /409 AM CDT Tue Sep 14 2021/

...BEACH HAZARDS STATEMENT IN EFFECT FROM THIS EVENING THROUGH LATE
TONIGHT...

This Hazardous Weather Outlook is for northern Indiana and
southwest Michigan.

.DAY ONE...Today and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Beach Hazards Statement.

See the latest surf zone forecast for additional details on the swim
risk today through Wednesday morning.

Thunderstorms are likely late this afternoon into early this evening.
Some storms could be strong to severe late this afternoon and early
this evening. The greatest potential threat is isolated to scattered
damaging wind gusts. Isolated large hail and torrential downpours
are also possible. The threat of severe weather will diminish by mid
to late evening.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

A Moderate Swim Risk for southeast Lake Michigan beaches will
linger into Wednesday morning. Breaking waves and currents are
expected. See the latest surf zone forecast for details.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed late this afternoon and early this
evening.

LMZ043-046-150915-
New Buffalo MI to St Joseph MI-Michigan City IN to New Buffalo MI-
509 AM EDT Tue Sep 14 2021

...SMALL CRAFT ADVISORY IN EFFECT UNTIL 5 AM EDT WEDNESDAY...

This Hazardous Weather Outlook is for the nearshore waters of
southeastern Lake Michigan.

.DAY ONE...Today and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Small Craft Advisory.

Scattered thunderstorms are expected late this afternoon and possibly
into early evening. Isolated strong to severe thunderstorms are
possible. A few storms may produce hail and wind gusts in excess of
40 knots.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

The probability of widespread hazardous weather is low.

Special Weather Statement
National Weather Service Northern Indiana
137 PM EDT Tue Sep 14 2021

INZ007>009-141800-
Noble IN-De Kalb IN-Steuben IN-
137 PM EDT Tue Sep 14 2021

...A strong thunderstorm will impact portions of southeastern
Steuben, northeastern Noble and northern De Kalb Counties through 200
PM EDT...

At 137 PM EDT, Doppler radar was tracking a strong thunderstorm near
Kendallville, moving northeast at 40 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This strong thunderstorm will be near...
  Waterloo around 145 PM EDT.

Other locations in the path of this storm include Angola and
Hamilton.

This includes the following highways...
 Interstate 69 in Indiana between mile markers 332 and 348.
 Interstate 80 in Indiana between mile markers 147 and 148.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4156 8480 4148 8481 4135 8520 4147 8532
      4153 8522 4153 8519 4155 8519 4172 8494
TIME...MOT...LOC 1737Z 237DEG 33KT 4146 8517

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

CM

Special Weather Statement
National Weather Service Northern Indiana
213 PM EDT Tue Sep 14 2021

INZ007-MIZ081-OHZ001-141845-
Steuben IN-Hillsdale MI-Williams OH-
213 PM EDT Tue Sep 14 2021

...A strong thunderstorm will impact portions of east central
Steuben, southwestern Hillsdale and northern Williams Counties
through 245 PM EDT...

At 212 PM EDT, Doppler radar was tracking a strong thunderstorm near
Edon, or 10 miles west of Montpelier, moving northeast at 40 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This strong thunderstorm will be near...
  Montpelier around 225 PM EDT.
  Pioneer and Holiday City around 230 PM EDT.

This includes the following highways...
 Interstate 80 in Indiana between mile markers 152 and 156.
 Interstate 80 in Ohio between mile markers 0 and 14.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4155 8481 4167 8488 4189 8462 4164 8441
TIME...MOT...LOC 1812Z 237DEG 33KT 4164 8478

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

CM