Area Forecast Discussion
Issued by NWS Northern Indiana

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553
FXUS63 KIWX 241400
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
900 AM EST Fri Feb 24 2017

.SYNOPSIS...
Issued at 420 AM EST Fri Feb 24 2017

It will remain unseasonable warm today. Severe weather remains a
possibility from mid to late afternoon into the evening hours as
storms develop ahead of a cold front moving through the area.
Highs today will be in the middle to upper 60s and even lower 70s
possible in northwest Ohio into east central Indiana.
Temperatures will then plummet back to seasonable levels late
tonight and continue through the weekend along with a chance for
snow showers.

&&

.UPDATE...
Issued at 831 AM EST Fri Feb 24 2017

Forecast updated to reflect continued mention of showers/isol
storms as nose of elevated instability works across the area. Few
higher reflectivity cores suggested a marginal severe hail risk
but thus far only pea to half inch diameter hail (lots of
lightning though). Once this passes by, vis sat shows at least
partial clearing if not a period of mostly sunny skies until
cloud cover begins to move back in with pre frontal trough.
Clearing should allow for a rapid warm up this morning into the
60s.

Lots of uncertainty with regards to severe potential this
afternoon/evening as a dynamically volatile, but moisture starved
environment will reside across the area. Main threat may end up on
the cold front itself late this afternoon into this evening with
mainly damaging winds (isolated tornado). Pre-frontal trough still
being shown as active on some of the hi res guidance so can`t let
our guard down this afternoon, especially seeing how vigorous
development has been in some areas this morning with elevated
storms. Strong capping should move in through much of the day
which may keep the pre frontal trough less active. 13Z SPC
outlook brought the slight and enhanced risks back to the west a
touch. Will continue to monitor the situation and update as
needed.

&&

.SHORT TERM...(Today and Tonight)
Issued at 420 AM EST Fri Feb 24 2017

Difficult forecast wrt thunderstorm chances/coverage/severity
today. At present scattered showers and a few/isolated weak storms
along/north of warm frontal boundary. Cold Lake Erie marine layer
continues to drive westward into far nern IN and undercut
elevated mixed layer. Suspect scattered showers/storms to continue
to slowly lift northward and weaken as capped prefrontal warm
sector finally begins to overtake marine influence beyond 12 UTC.
Then afford a lull in precip chances as remain largely capped
until mid to late afternoon with culmination of strong eml 8.5-9
c/km with modest low level moisture pooled as only mid to upper
50s dewpoints expected. Will likely have to wait for strong forced
frontal ascent which lags upstream until about 21-22 UTC...once
the surface frontal wave now into northeast MO reaches southern
Lake Michigan/extreme sw MI. Scattered convection develops ahead
of southward trailing cold front amid strong 50 to 60 kts deep
layer shear across western cwa initially and likely merging into
linear segments/squall line with time and eastward progression.
Leading edge of increasingly strong mid level height rises and
divergent upper jet region to allow longevity/sustenance until
east/southeast cwa exit around 03-04 UTC. Low wet bulb zero for
potential large amounts of small hailstones associated with
updraft cores. But loading/melt/evaporative cooling amid already
strong mid level winds to present with heightened/primarily isold-
sct damaging wind risk, especially across eastern half of cwa in
latter part of event. Initial storms however may present with
supercellular aspects and low tornado risk across far northern cwa
in closer proximity to triple point/frontal boundary...especially
if aforementioned Lake Erie marine layer proves difficult to
expunge.

&&

.LONG TERM...(Saturday through Thursday)
Issued at 420 AM EST Fri Feb 24 2017

Continued with similar rapid transition to snow potential late
tonight/early Saturday. Otherwise little change to blended
approach with another similar/weaker tracked system with best
rain chances about Tue/Tue night. This system appears bounded in
time by much weaker/clipper systems before and afterwards and
nudged downward the sometimes overzealous blended pops.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
Issued at 640 AM EST Thu Feb 23 2017

Improved conditions ahead this afternoons convection as warm
sector continues to deepen/move northward. Similar timing with
respect to thunderstorms with greater potential for
strong/potentially severe/greater than 50 kt gust...subsevere for
terminal forecasts at this time given isold-sct nature. Changeover
to snow showers with lowest conditions invof KSBN late in the
forecast period.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

UPDATE...Fisher
SYNOPSIS...Murphy
SHORT TERM...Murphy
LONG TERM...Murphy
AVIATION...Murphy


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