IND issues Area Forecast Discussion (AFD) at Nov 5, 2:59 AM EST901
FXUS63 KIND 050936
AFDIND
Area Forecast Discussion
National Weather Service Indianapolis IN
259 AM EST Tue Nov 5 2024
.KEY MESSAGES...
- Windy today with peak gusts 45 to 50 mph possible northwest
- Near record warmth today
- Rain and a few storms late this afternoon into tonight
- Warmer than normal temperatures will continue into the weekend...
rain chances to return to entire region Saturday-Sunday
&&
.SHORT TERM (Today and Tonight)...
Issued at 259 AM EST Tue Nov 5 2024
Warm and windy early November morning ongoing with strong southerly
flow across the Ohio Valley. Rain that had impacted the Wabash
Valley on MOnday evening had shifted to the north into northwest
Indiana and northeast Illinois. 07Z temperatures were in the mid and
upper 60s...running a solid 10 degrees above the average high for
early November.
The cold front that has remained to our west over the last couple
days will finally kick east towards the region later today bringing
more widespread rain. As an upper low over the middle of the country
lifts northeast it will weaken and become absorbed in the mean flow
aloft by late day...blocked from moving further east by the strong
ridge centered over the Southeast states. Despite the presence of
the ridge to the southeast...the overall upper level flow will
transition to a flatter southwest regime which in turn will shift
the surface ridge along the East Coast further offshore.
Ultimately...this will enable the cold front to move into the Ohio
Valley by late day before slowing down tonight as it becomes more
parallel to the southwest flow aloft.
Initially to start the morning...rain and storms will be largely
displaced to the northwest in closer proximity to the track of a
surface wave lifting from the Missouri Valley to the western Great
Lakes. Scattered showers are possible for a few hours prior to
daybreak across the northwest half of the forecast area. The surface
ridge to the east has reexerted its influence at least
temporarily...and this will keep dry conditions elsewhere across the
area through daybreak with the southeast half of the forecast area
even experiencing generally clear skies as well which should last in
some manner through at least midday.
WINDS
The main focus through midday will be on wind gusts which have
already shown an uptick over the last few hours...aided both by a
tightening of the surface pressure gradient and the return of a
stronger low level jet. Peak wind gusts to 25 to 30mph have already
occurred so far this morning and should only become more frequent as
the jet aloft strengthens. Once deeper boundary layer mixing
establishes by late morning...winds will likely be at their
strongest into the afternoon with gusts at 40 to 45mph becoming
common.
The highest wind gusts will focus across the northern Wabash Valley
in closest proximity to the low level jet. An occasional gust
approaching 50mph this afternoon is not out of the question in this
area and this is covered within the ongoing Wind Advisory. Have no
plans to make changes to the start and end times of the Advisory or
to extend further to the southeast based on thoughts above. Will
discuss the convective potential in the section below...but think
there is a chance to see locally stronger winds briefly accompany
any heavier showers or storms this evening before winds begin to
slowly drop back as the front passes.
RAIN/STORMS
Confidence continues to grow on widespread rainfall moving from
northwest to southeast across the area late today into tonight with
the cold front. There has been a noted slowing of the arrival of the
main area of rainfall by a few hours within the 00Z model suite...
likely due to the surface ridge hanging on across the Ohio and
Tennessee Valleys for a touch longer this afternoon before shifting
further east into the Atlantic tonight.
Showers may come in a couple of waves...with the first batch moving
east across the forecast area near sunset aided primarily by the low
level jet. This would then be followed by a band of convection that
may carry a few rumbles of thunder riding along the frontal boundary
this evening and in tandem with a deep low level convergence axis
and forcing aloft courtesy of the right rear quadrant of the upper
jet. Overall instability profiles are not impressive but the BL
shear profiles are more than sufficient to generate a low topped
QLCS-type line that could briefly produce localized strong but
likely subsevere wind gusts. Have confined any mention of thunder to
southern portions of the forecast area where instability is
greatest.
As the front becomes more parallel to the southwest upper flow...the
boundary will slow overnight with rain likely to persist across much
of the southeast half of the forecast area into the predawn hours
and possibly as late as daybreak Wednesday. The convective potential
noted above during the evening should gradually diminish overnight
as any meager instability is fully lost and the boundary layer
becomes saturated. Rainfall amounts are not expected to be
impressive but much of the area should see 0.50 to 1 inch by
Wednesday morning which will certainly be welcome. Highest amounts
will be focused over southeast counties where the rain will linger
longest through the night as the front slows.
Temps...the slower arrival of rain late today and the potential for
a decent amounts of sun across the southeast half of the area into
early afternoon will have a positive influence on temp rises that
will push record levels. The record high for today in Indy is 76 set
in 1975...1978 and most recently in 2015 and this will be threatened
this afternoon. Low level thermals are strongly supportive of mid
and upper 70s over most of the forecast area. Lows tonight will
range from the upper 40s over the northern Wabash Valley to near 60
across southeast counties.
&&
.LONG TERM (Wednesday through Monday)...
Issued at 259 AM EST Tue Nov 5 2024
Wednesday through Friday...
Quieter weather will be in store for the remainder of the workweek,
with the frontal zone pushing east into Ohio just before daybreak
Wednesday. Surface high pressure aligned from the northern Plains
into the Great Lakes will extend its southern portions into most of
central Indiana through Friday...while lingering, lower chances of
showers remain south of I-70 through Wednesday night just behind the
decaying frontal zone hanging over the Ohio Valley. Temperatures
will remain above normal as the next broad/plunging upper trough
over the western CONUS shifts heights upward through the central US.
Max and min readings should both near 10 degrees above normal
across the region, albeit amid mainly light breezes.
Saturday through Monday...
The broad upper ridge that has dominated across much of North
America so far this fall...will try yet again to at least briefly
build north into southern Canada. Nevertheless a broad cut-off H500
trough should gradually advance from the southern Plains into the
Great Lakes. Indiana's proximity to the southeast of its track
should place us amid broad conveyors of increasing precipitable
water from perhaps both the Gulf and Atlantic.
So far, considerable cloudiness, sub-normal diurnal temperature
ranges that are overall unseasonably mild, and scattered to numerous
rain showers are the expectation. Less certainty surrounding
timing, location, and amount of steadier to possibly heavy rainfall
given the typically wobbly nature of self-driving cut-off
circulations and guidance so far exhibiting a lack of any more
potent axis of better moisture advection. That said pwat values in
the 1.25-1.75 inch range for most of the CWA for 36 hours should
bring 1-2 periods of organized rain to most locations. An
additional wild card to this equation is a potential tropical wave
whose potential proximity near the Gulf coast around the Saturday
timeframe could contribute to the moisture conveyor directed at the
Ohio Valley, if not southern Indiana. The normal max/min at
Indianapolis through the long term is 55/37.
&&
.AVIATION (06Z TAF Issuance)...
Issued at 1152 PM EST Mon Nov 4 2024
Impacts:
- Gusty winds late tonight through Tuesday with over 30kt expected
at times
- Non-convective low level wind shear through Tuesday morning
- MVFR ceilings late Tuesday afternoon into Tuesday evening with
showers
Discussion:
The broad area of rain continues to shift north late this evening
and should be north of KLAF by 05-06Z. The rest of the overnight
will be quiet with focus for aviators shifting to winds which will
become increasingly gusty from the south through daybreak Tuesday.
Peak gusts will be near 25kts by the predawn hour. Low level wind
shear will also impact the terminals into Tuesday morning as well.
Mid and high clouds will thicken quickly on Tuesday morning as the
cold front to the west pivots east across the Missouri Valley.
Widespread rain will not make it into the region until mid to late
afternoon then slowly track east across central Indiana during the
evening. Could see embedded convection but for the most part...not
likely to see thunder at the terminals. Potential for higher
rainfall rates to briefly pull visibilities down to MVFR or lower
during the evening as well. MVFR stratus will accompany the rain
from west to east before returning to VFR towards the end of the
forecast period.
Winds will remain a major impact for aviators all day Tuesday with
gusts peaking as high as 35kts or so during the afternoon.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 7 AM this morning to 3 PM EST this afternoon
for INZ021-028>031-035-036-043-044.
&&
$$
SHORT TERM...Ryan
LONG TERM...AGM
AVIATION...Ryan
Source:
IND issues Area Forecast Discussion (AFD) at Nov 5, 2:59 AM EST---------------
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