949
FXUS63 KIWX 310746
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
246 AM EST Fri Jan 31 2025

.KEY MESSAGES...

- Rain continues today with up to an inch possible in NW IN/SW
  MI. This may cause isolated ponding of water in typical low
  spots.

- Areas of dense fog will also continue through the morning.

- Primarily dry conditions are expected over the weekend into
  early next week with temperatures at or above normal.

&&

.DISCUSSION...
Issued at 245 AM EST Fri Jan 31 2025

Round 1 of rainfall associated with initial theta-e/WAA surge and
some 700mb fgen is now waning. A lull in steadier rain will persist
through the early morning with areas of fog and drizzle likely.
Dense fog has not been widespread and guidance suggests it will
remain more patchy through the morning but enough sites reporting
visibility of 1/4SM to warrant a dense fog advisory. Included the
entire area with expectation that fog will expand north as the rain
exits. Some improvement in the S/SE is possible and advisory may be
cancelled early there.

Round 2 of rain will ramp up after 12Z. This round is being driven
by strong deformation/fgen in the left exit region of approaching
mid/upper level jet streak as well as some CVA-driven ascent over
our south with the passing vort max. By far the heavier precip
amounts will be with the deformation axis in our north mainly during
the afternoon hours. Here strong fgen with reduced stability aloft
will favor some highly efficient precip despite best moisture being
shunted well to the east. Localized amounts near an inch are
possible in a 6-9 hour window across our NW zones today and this
could lead to some minor ponding in typical low spots. Despite
recent moderation in temps frost depth at the office yesterday was
around 7 inches with 0 inches thawed so far. Suspect some thawing
has occurred with the rain and continued warmth but nevertheless the
ground is cold and much of this rain will simply runoff. Still a few
inches of snow on the ground in parts of Berrien County but overall
our snowpack is gone thankfully and rivers are starting at
relatively low levels. Therefore suspect any high water issues to be
marginal/isolated and not worth a flood watch. Precip will end
quickly this evening with dry conditions everywhere by 03-04Z. Some
colder air does filter south during this time and wouldn`t be
surprised to see a few snowflakes as precip ends but cold air is
just too little too late to support any accumulating snow.

Very little change in the weekend forecast as brief shot of CAA Sat
quickly whips around to strong WAA for Sun. Highs Sat stuck in the
30s while 50s return for Sun. The shortwave responsible for this
strong WAA will cross the central Great Lakes with minimal precip
this far south. (Just a low chance rain in our far north.) After a
dry/tranquil period to start the week, a baroclinic zone looks to
set up somewhere over the Midwest during the middle-late week
period. Continued with primarily rain mention as most guidance
members are in that camp for the start of the event. However,
confidence is low as there is still a lot of variability that could
impact temps and precip types, particularly later in the week as
high pressure and colder air finally make a southward return. Stay
tuned as there is still plenty of time for significant changes to
the forecast at that time range.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1214 AM EST Fri Jan 31 2025

The initial band of rain has lifted north, well ahead of a
surface low over northern MO. This system will move quickly east
and spread more rain back across northern Indiana. IFR
conditions should prevail through most - if not the entire TAF
period, although some breaks in the clouds are likely near or
after 06Z.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Dense Fog Advisory until 10 AM EST /9 AM CST/ this morning for
     INZ005>009-012>015-017-018-020-022>027-032>034-103-104-
     116-203-204-216.
OH...Dense Fog Advisory until 10 AM EST this morning for OHZ001-002-
     004-005-015-016-024-025.
MI...Dense Fog Advisory until 10 AM EST this morning for MIZ078>081-
     177-277.
MARINE...Dense Fog Advisory until 10 AM EST this morning for LMZ043-046.

&&

$$

DISCUSSION...AGD
AVIATION...Skipper