IWX issues Area Forecast Discussion (AFD) at Dec 15, 5:18 AM EST
474
FXUS63 KIWX 151018
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
518 AM EST Sun Dec 15 2024
.KEY MESSAGES...
-Chances for rain or drizzle will persist through much of the
day, tapering off from west to east through this afternoon and
evening. Widespread rain is expected through the day on Monday.
Expect around one quarter to three quarters of an inch of
rain, greatest totals along and south of US 24.
-Dry conditions under partly to mostly cloudy skies are expected
Tuesday into Tuesday evening, with intermittent low to mid
range chances for rain and snow returning for the latter half
of the work week.
-Highs today and Tuesday will be in the upper 30s and low to mid
40s. Highs on Monday will climb into the 50s. Lows will be in
the 30s and 40s. Colder from mid week into the weekend, with
highs in the 20s and 30s and lows in the teens and 20s.
&&
.DISCUSSION...
Issued at 517 AM EST Sun Dec 15 2024
Allowed the winter weather advisory to expire as we have not heard
much in the way of impacts from any freezing rain or sleet that
occurred-and temperatures have finally risen above freezing
(Hillsdale is at 34F, further south in the upper 30s and low 40s).
Rain associated with the moisture/warm air transport is beginning to
shift eastward this morning, with drizzle or dry conditions in the
wake. The surface low currently centered over IA will lift east-
northeast through the day, eventually dissipating as it runs into
the record-breaking high pressure off the eastern seaboard
(currently at 1049 hPa, yesterday was 1050 hPa). Pressure records in
Dec for Quebec/Ontario range between 1046-1049hPa (set in Feb 1981
for all time record).
Additional showers are expected along the occlusion before the low
fills all together over our CWA somewhere, with the upper low
continuing eastward into the Lower Great Lakes and eventually the
east coast. Near the center of the low upstream we have dense
fog/areas of fog, however by the time it gets into our area expect
it to be more patchy in nature (especially as we go into the
afternoon). Carried patchy fog for now, though we have an increase
in the visibility in our southwest away from the rain showers (But
we have 1/2SM vis at KTIP, 2SM at KRZL, KIKK, and KPPO].
After a quick break in precipitation late this afternoon into the
evening hours, expect additional rain to move in late tonight into
Monday ahead of the next system. Warm air advection on a 45-50 kt
LLJ really ramps up around 3-6z and takes aim right at our CWA,
pulling moisture up along a cold front to the west. The cold front
stems from the low pressure system over the Dakotas/MN/Northern
Ontario, and there is a second low that develops in the Central
Plains, riding northeastward along the front. Expect the warm front
to be on our southwestern doorstep by 12z Mon, then the low will
cross our CWA as it occludes, with the triple point moving generally
along US 6. By 00z Tue, the low is near Sandusky, OH. How much warm
air and moisture we can transport into our area is the question,
with models backing off on the somewhat more aggressive QPF
solutions. This is likely because the southern wave generates
convection to our south as the overall system moves east, which can
sometimes hog the moisture and keep the warmer air further south.
The better forcing (outside of the potential moisture transport/waa)
does remain further to the north of our CWA, so expect we'll see at
least some widespread rain/shower activity. Still have highs in the
50s Monday (850mb temps to 8-10C), and around 0.25 to 0.75 inches of
rain in the forecast.
Later Mon Night-Tuesday evening looks to be dry as we get beneath
slight ridging/somewhat zonal flow aloft and surface high pressure,
with partly to mostly cloudy skies (best chance for sun further
south). Highs will be in the 40s, and lows will be in the 30s.
Wednesday into the weekend is still a bit uncertain as models differ
with respect to the broader synoptic pattern. At some point, a
digging trough will encompass most of the east coast and the Great
Lakes region (how far south and the exact timing is still in
question). Similar to Monday's situation, convection with the
southern portion of the wave may limit how much moisture
transport lifts into our area-so kept the pops fairly limited.
Have 30-50 percent for most of the area Wednesday, and closer to
60 percent along the southern forecast area border where there
is better moisture. Highs will be in the 40s Wednesday but fall
into the 30s by the late afternoon, then the 20s and low 30s
overnight-so precipitation will be a mix of rain/snow. While
there may be some lingering lake enhanced showers behind the
exiting system into Thu (GFS) they look pretty limited thanks to
strong sfc high pressure building in behind it. Anything that
does form near the lake should be shortlived, leaving it mostly
dry for Thursday.
Friday into the weekend, a low pressure system crosses Lower
Michigan-with the best forcing north of our area. Best chances will
be north of US 30 and near Lake MI as we'll see decent NW flow and a
shot of colder air (850 mb temps -14C to -16C). Highs will only be
in the 20s and 30s.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1240 AM EST Sun Dec 15 2024
Deteriorating aviation are expected through the remainder of
the night, with little opportunity for improvement for most of
this forecast valid period.
Strong pre-frontal forcing in the form of confluence zone
associated with 40-50 knot low level jet and good deal of low
level moisture advection has been supportive of widespread rain
across northern Indiana. A few reports of some mixed precip have
been confined to extreme northeast Indiana. Precip should stay
in the form of all rain through the remainder of the night, and
rain will continue as primary upper low center drifts eastward
from west central Illinois. This wave will be in a decaying
state as it tracks eastward into Sunday with sfc reflection of
this system also weakening across northern Illinois. A weakening
gradient and copious amounts of low level moisture should give
rise to widespread fog/stratus. Bulk of the worst fog conditions
may linger back into Illinois, but IFR/LIFR cigs will become
more prevalent after 09Z and through daybreak across northern
Indiana. A break in precip chances in anticipated Sunday
afternoon, but more rain showers are expected just beyond this
forecast valid period early Monday morning. Have also maintained
LLWS mention for the first 3-6 hours of the TAF period in
association with the aforementioned low level jet.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.
&&
$$
DISCUSSION...MCD
AVIATION...Marsili
Source: IWX issues Area Forecast Discussion (AFD) at Dec 15, 5:18 AM EST (https://mesonet.agron.iastate.edu/p.php?pid=202412151018-KIWX-FXUS63-AFDIWX)
---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!