000
FXUS63 KIWX 141036
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
636 AM EDT Sun Apr 14 2024

.KEY MESSAGES...

- Ongoing river flooding should gradually improve; however, the
  potential for heavy rainfall this upcoming week may once
  again renew river flooding with several chances for showers
  and storms in a very moist environment.

- Isolated thunderstorms are possible this evening southeast of
  Ft Wayne. The best chance for severe thunderstorms is Tuesday
  into Wednesday.

- Warm today through Wednesday with highs in the 70s. 80
  possible today. Turning cooler late in the week with a chance
  of freezing temperatures this upcoming weekend.

&&

.DISCUSSION...
Issued at 316 AM EDT Sun Apr 14 2024

An upper level system over the Upper Midwest was dropping
southeast in tandem with a cold front and should reach the area
by early tonight. Ahead of this system, a unmodified elevated
mixed layer (EML) was already becoming entrenched over the
forecast area. Substantial/steep 700mb/500mb lapse rates from
8.0 to 8.5C/Km will provide an environment for potentially
stronger storms. However, the latest GFS trends include more
limited CAPE (under 1000 J/Kg) with a stronger cap at the base
of the EML. SPC earlier had removed the marginal severe storm
risk. There is a good chance fairly strong capping may partially
or completely inhibit storm development as indicated by most
CAMS.

For Monday into Thursday, it looks like the storm mode will
evolve into more of a heavy rain threat with tall but thin
CAPEs and high precipitable water values as the EML mixes out.
It appears the best chance for severe storms is late Tuesday
into Wednesday as strong negatively tilted trof with an
associated upper low reaches the area. SPC has updated the 15%
severe risk for the "old" Day 4 to a slight severe storm risk
over far southwest area including Monticello on the new Day 3.
Ongoing mainly river flood issues persist today across the
Upper Wabash especially south of Ft Wayne where several roads
remain closed from the Bluffton area down to Geneva. Some
improvement in the flood situation is expected before addition
rainfall arrives later this week. This additional rain may
aggravate the current situation. Otherwise, a cooler and drier
pattern change will begin late this week with as a longwave
trof axis sets up over east North America. Temperatures may drop
to freezing this coming weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 635 AM EDT Sun Apr 14 2024

An upper level vort max associated with an upper jet streak
across the northern Great Lakes will allow sfc trough to drop
southward across northern Indiana this afternoon. Low level flow
will gradually diminish this morning, but good low level mixing
should provide at least a period of 25+ knot gusts this morning
through early afternoon. Will continue to carry a few hours of
LLWS criteria at both terminals to begin the forecast valid
period. The main forecast challenge into this afternoon will
center on potential of any isolated convection across NE
Indiana. A warm nose above mixed layer should provide some
convective inhibition for surface based parcels through mid
afternoon. By the time this warm layer cools substantially,
surface based instability begins to wane past peak heating
period this afternoon. Better potential of any isolated
convection still appears to be southeast of KFWA and will keep
dry forecast going. Sfc ridging will settle into southern Great
Lakes later tonight as the weak cold frontal boundary stalls
across central Indiana.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.

&&

$$

DISCUSSION...Skipper
AVIATION...Marsili