Office: IND
FXUS63 KIND 191834
AFDIND
Area Forecast Discussion
National Weather Service Indianapolis IN
234 PM EDT Fri Apr 19 2024
.KEY MESSAGES...
- Partly Cloudy Tonight and Saturday; Cooler
- Some frost potential Sunday morning, more widespread frost
possible Monday morning.
- Increasing rain chances next Tuesday, chance for PM thunderstorms
- Temperatures generally near seasonal next week, but brief cooldown
is possible Wednesday into Thursday
&&
.SHORT TERM (This evening through Saturday)...
Issued at 230 PM EDT Fri Apr 19 2024
Synopsis:
Surface analysis this afternoon shows Low pressure north of Lake
Ontario, with a cold front that extended southwest across eastern OH
and eastern KY to Northern AL. Strong high pressure was found over
the Dakotas, with a surface ridge axis extending southeast across
NB, northern MO and into Central IL. GOES16 shows the back edge of
clouds associated with the cold front just about to exit southeast
Indiana. Higher clouds were found upstream over MO and IL, streaming
toward Central Indiana. Cool northerly surface flow was in place
across Central Indiana due to the arriving area of high pressure.
Aloft a deep upper low pressure system was found over northern
Ontario. This system was providing mainly a westerly flow aloft over
the plains and Ohio Valley, with a stream of Pacific moisture in
place.
Tonight...
Quiet, and cold weather is expected tonight. Cold north/northwest
surface flow is expected to continue overnight as the surface high
pressure system will remain over the northwest plains. This will
continue to allow cool, continental air to spill into the Ohio
Valley from Canada. Meanwhile aloft, little overall change is
expected as the upper low is expected to pivot northeast and the
westerly flow with little to no forcing in place will remain in
place. Given upstream satellite and the quick flow aloft, periodic
mid and high clouds will be expected to pass through the night.
Forecast soundings agree to this, showing dry lower levels through
the night given the cool and dry lower level flow, but saturation
appears aloft from time to time, suggesting passing mid and high
clouds. Thus partly cloudy should work fine.
Cold air advection will remain in play overnight. However the
ongoing pressure gradient across the area should help to keep winds
between 5-10 mph. This along with passing high clouds should be
favorable for the prevention of frost. Expect lows in the middle to
upper 30s north and central, and near 40 south.
Saturday...
Little overall change is expected in the weather on Saturday. The
upper flow remains westerly with Pacific moisture flowing aloft.
Models suggest the lower levels will remain dry with cool, northerly
or northwest flow spilling into Indiana as the surface high remains
strongly in place over the high plains. Forecast soundings again
show dry lower levels with a steep inversion in place within the mid
levels, limiting any cloud development. Upper levels show dry air
aloft with subsidence in place. Thus only a few stray passing high
clouds will be expected from that high, limited, Pacific moisture
aloft. 850Mb temps are expected to linger around -3C, thus a cool
day will be in store. Look for highs only in the lower to middle 50s.
&&
.LONG TERM (Saturday night through Friday)...
Issued at 230 PM EDT Fri Apr 19 2024
Saturday night through Monday...
Quiet weather conditions are expected as surface high pressure
remains dominant over the region. Aloft, guidance shows an
impulse traversing the region which could help to increase cloud
cover late Saturday into early Sunday. Expect the cooler pattern
today to continue over the weekend due to cold air advection. Lows
dropping into the 30s both Sunday and Monday morning combined
with relatively light winds supports the potential for frost.
There is higher confidence in frost Sunday night into Monday
morning at this time since guidance shows mostly clear skies.
Greater cloud cover from the aforementioned upper level impulse
Saturday night into Sunday morning leads to greater uncertainty in
terms of coverage. Highs in the mid 50s to near 60F Sunday should
warm well into the 60s to start the work week due to return flow.
Monday night onward...
Rain chances return towards daybreak Tuesday as a shortwave trough
and associated low pressure system move across the Great Lakes
Region. Return flow ahead of the approaching system should allow for
temperatures to continue moderating. Sufficient moisture return
combined with increasing dynamics supports likely POPs on Tuesday.
The system is likely going to move out Tuesday night.
Cold air advection and surface high pressure building in behind the
departing low will allow for quiet weather conditions to return
briefly before another system approaches late next week. Models
begin to diverge significantly by this point which limits forecast
confidence, but there is a general signal for an active pattern
heading into next weekend. Temperatures likely falling into the 30s
Thursday morning leads to some frost concern though it appears winds
may remain elevated enough to limit this potential. This will be
worth monitoring as blended guidance can sometimes overestimate the
magnitude of nocturnal winds when surface high pressure is building
in.
&&
.AVIATION (18Z TAF Issuance)...
Issued at 1236 PM EDT Fri Apr 19 2024
Impacts:
- VFR Conditions are expected this TAF period.
Discussion:
GOES16 shows the back edge of clouds associated with the passed cold
front have exited the TAF sites. This will lead to continued VFR
conditions as strong high pressure centered over the Dakotas begins
to build across Indiana and the Ohio valley.
GOES16 also shows to mid and high cloud over IL. These are poised to
push across IND and HUF through the late afternoon hours, but
conditions will still remain VFR. Forecast soundings through this
afternoon show dry lower levels with periodic saturation aloft due
to these passing high clouds.
Dry lower levels persist through Saturday morning and VFR conditions
will be expected to continue through that time.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Puma
LONG TERM...Melo
AVIATION...Puma
Office: IWX
FXUS63 KIWX 191806 CCA
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
156 PM EDT Fri Apr 19 2024
.KEY MESSAGES...
- Dry and cool this weekend with frost possible Sunday morning.
&&
.DISCUSSION...
Issued at 1136 AM EDT Fri Apr 19 2024
Omega blocking pattern present over western Canada which will be
interesting to see what kind of temporal issues are encountered
with the latest modeling data. Typically the models become more
progressive with blocks and so the actual atmospheric evolution
may be hours to days pushed back. Having said that the eastern
trough of this omega block will sit over the Great Lake region
bringing colder and drier conditions. Highs Saturday will
struggle to get out of the 40s. We then have our main concern
this weekend which will be Sunday mornings low temperatures and
potential morning frost. With many plants having emerged or in
the process of emerging will be susceptible to frost damage.
Clouds will be in focus on Sunday morning as if lingering low to
mid level clouds are still in place that would be enough to keep
low temperatures up a degree or two. The better chance for cloud
cover will be the southern half of the CWA, which means the
better chance for frost will be the northern half of the area
and areas away from Lake Michigan. So northwest OH, northeast
IN, and southeast MI will have the higher chances for frost.
Lows on Sunday will range from 30 to 35 degrees. We will
continue to monitor this situation in subsequent shifts for any
potential advisory issuance.
Dry weather continues at least through Monday. As mentioned
earlier the blocky pattern may cause forecast headaches as
earlier runs had a trough dropping into the region late Monday
into Tuesday but looks to be pushed back into later in the day
on Tuesday. This trough would present the next chance of
precipitation and another shot at cooler air with highs in the
50s on Wednesday and lows back into the 30s by Thursday
morning. May need to watch for another potential frost event.
Ridging then returns on Thursday and temperatures will gradually
warm once again with highs back into the low 60s.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1228 PM EDT Fri Apr 19 2024
Dry, cool and somewhat breezy conditions will persist in wnw through
the TAF cycle.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 4 PM EDT Saturday for LMZ043-046.
&&
$$
DISCUSSION...Andersen
AVIATION...Steinwedel
