Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/15/22
Area Forecast Discussion
National Weather Service Indianapolis IN
1201 AM EDT Sat Oct 15 2022
...Updated Aviation Discussion...
Issued at 936 PM EDT Fri Oct 14 2022
No major changes needed with the ongoing forecast as conditions are
generally evolving as expected. The area of rain over central
Illinois associated with the approaching trough will arrive in the
northwestern counties after 10 PM with a few hundredths of an inch
of rain for those counties through 2 AM. The primary concern with
these showers will be the potential for stronger wind gusts as the
rain helps bring down the 40kt winds at cloud level. We`ve already
seen a few gusts to 30kts ahead of the rainfall at LAF and FKR but
as the temperatures continue to cool, the frequency of the stronger
gusts will gradually decrease. Latest ACARs soundings show a
minimal amount of elevated instability with these showers, so can`t
rule out a few pieces of graupel in the stronger showers.
Lows in the mid to upper 30s across the northwestern counties still
looks probable, but will be dependent on how quickly the clouds
begin to clear in the aftermath of rainfall. Will monitor these
conditions through the night and make adjustments as needed.
.Short Term...(This evening through Saturday)
Issued at 226 PM EDT Fri Oct 14 2022
* Critical Fire Weather conditions this afternoon
* Gusty winds 35 to 45 mph
* Showers possible this evening with gusty winds
Temperatures across the region have warmed into the upper 50s to
near 60 as of 2pm. Excellent boundary layer mixing to as high as
700mb has allowed for efficient downward transfer of momentum aloft.
Low-level flow within the 925 to 700 mb layer is around 30 kts,
based on soundings out of ILX. Winds at the surface have been
gusting consistently to around 25 kts at IND late this morning and
early this afternoon. A potent shortwave trough is modeled to reach
Indiana by around 8pm this evening, and in the process gain a
negative tilt. Winds in the aforementioned layer should increase as
this feature closes in, with 850mb flow increasing to 40kts and
700mb flow to around 60kts. Therefore, wind gusts should gradually
increase through the afternoon before tapering off as solar
insolation is lost and stability returns. Gusts could top out around
35kts for most locations before the day is out.
Additionally, very dry air in the lower levels is mixing down to the
surface. Dew points at IND are already in the upper teens, with RH
values around 16 percent as of 2pm. Skies have been trending clearer
than forecast, so the lower end of guidance regarding RH is
preferred for the remainder of this afternoon. Continued mixing
should lead to RH values dropping to as low as 15 percent in places.
The very dry and cloud-free air and deep mixing should allow high
temperatures to reach their full potential this afternoon, which
would generally be in the mid to upper 60s based on nearby soundings.
The combination of dry and windy weather will lead to critical fire
conditions today. Recent lack of significant rainfall has lead to
low fuel moisture levels, currently between 7 to 10 percent as of
yesterday. Any fires that manage to ignite today will have little
issue spreading, so the Red Flag Warning issued previously is
maintained through 8pm.
The potent shortwave arrives this evening, with increasing clouds
and potentially a few showers. As mentioned before, the low levels
are very dry, so widespread rainfall is not anticipated. But strong
positive vorticity advection and diffluence aloft will lead to an
enhanced area of lift as the system moves through. Additionally,
some weak CAPE around 100 J/kg at the top of the mixed layer may
enhance the convective nature of any showers this evening. In fact,
some of the CAMs, namely the HRRR and 3km NAM, depict a more
cellular appearance to the shower activity this evening. Model
soundings indicate that any convective elements would be rather
shallow, as a broad cap resides around 600mb. Nevertheless, strong
low-level flow as mentioned earlier could easily be brought to the
surface within the stronger showers. Therefore, wouldn`t be
surprised to see some non-severe gusty winds associated with shower
activity later on. The best chance would be north of a Terre Haute
to Indianapolis line, which is closer to the best dynamics ahead of
the approaching shortwave. The synoptically driven wind should die
down quickly as daytime heating is lost, as it is primarily driven
by surface mixing. Wind associated with the showers could persist a
bit longer, however.
As the system departs, skies should gradually clear throughout the
night. Large scale troughing over the Great Lakes is maintaining a
cooler air mass aloft, which should allow for a rather chilly
overnight if ideal radiational cooling conditions materialize. Weak
surface CAA / a cold front behind the shortwave will aid in cooling
potential overnight. The most likely locations for maximized cooling
would be the northwestern part of the CWA, which is deeper into the
post-front air mass and will see clearing earlier compared to places
further south. Lows should dip into the mid 30s across our north,
but only into the low 40s south of Indianapolis. Patchy frost is
possible, but dry low-levels and a residual breeze should prevent it
from being too widespread.
Benign weather is anticipated to start the weekend, at least
compared to today`s weather. Surface high pressure will be in
control, and light winds along with mainly clear skies should
prevail. An area of high clouds may arrive mid afternoon as a weak
wave aloft slides in from the west. High temps are expected to be
cooler than today, but not significantly so.
.Long Term...(Saturday night through Friday)
Issued at 226 PM EDT Fri Oct 14 2022
Significant Weather Highlights:
* Widespread freeze conditions likely multiple mornings early-mid
* Hard freeze possible, which would officially end growing season
A fairly stagnant upper level pattern is expected much of the long
term period, featuring a western CONUS ridge/Rex block and eastern
CONUS trough/closed upper level low.
This will lead to mainly dry conditions, with much below normal
temperatures expected for at least a significant portion of the
period, particularly the early to middle portion of the coming work
A dry cold front will move through the area late Sunday, followed by
a blast of cold air accompanying a strong surface high pressure
system driven southward in the highly amplified flow by a nearly
meridional polar jet stream. The overall cyclonic flow aloft will
allow some lake effect clouds and perhaps a low chance for light
precipitation to nudge into northern/northeastern portions of
central Indiana late Monday into Tuesday, but the larger story will
be the anomalously low temperatures, which look nearly certain to
deliver widespread freeze conditions one or more nights next week,
with a hard freeze not out of the question (which would officially
end the growing season and frost/freeze headlines for the area).
Ensemble data suggest that Tuesday night should be the coldest
period, with temperatures quite cool about 24 hours either side of
this time, and suspect that blend may be underselling the degree of
the cold expected. Will be trending temperatures, especially lows,
toward the low end of the guidance envelope as a result. Lake effect
could complicate this in the north/northeast, but these
uncertainties will come into clearer view with time. Nonetheless,
well below normal temperatures will dominate much of the long term
period, with some moderation in temperatures expected very late in
.Aviation...(06Z TAF Issuance)
Issued at 1201 AM EDT Sat Oct 15 2022
- VFR Conditions are expected this TAF period.
A cold front quickly moving across the TAF sites will quickly exit
the area within 1-2 hours after 06Z. GOES16 shows mainly mid level
cloud across the region with this feature. These VFR clouds will
quickly exit to the east overnight as the front departs and high
pressure centered over IA/NB begins to push into IL and IN.
Although cyclonic flow is expected to remain in place aloft
overnight and the rest of Saturday, the surface high pressure to the
west will continue to build across Indiana. Forecast soundings show
a very dry column through the rest of the period with unreachable
convective temperatures. Thus continued VFR conditions.
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
856 PM CDT Fri Oct 14 2022
Issued at 855 PM CDT Fri Oct 14 2022
The current forecast remains in good shape this evening with just
minor adjustments made to match trends.
A cold front which is located along the I-57 corridor continues
to push eastward across the area this evening which has lead to
the widespread showers that are moving into northwestern Indiana.
These showers will gradually come to an end as the front clears
the area around midnight with clearing skies and easing winds
expected for the rest of the overnight hours. The clear skies will
allow temperatures to cool into the low to mid 30s across most of
the area with a few sites possibly dipping into the upper 20s.
The expectation of widespread temperatures near or below freezing
has prompted the issuance of Freeze Warning for portions of
northern and northwestern Illinois which means that those in this
area with sensitive plants should take measures to protect them
from the cold.
As for our Saturday, expect temperatures to top out in the low to
mid-50s tomorrow afternoon with partly sunny skies. Winds will
also be a tad breezy again, but with gusts around 20 mph during
the afternoon. Similar conditions are expected for Sunday with
slightly warmer temperatures in the mid to upper 50s.
Issued at 302 PM CDT Fri Oct 14 2022
Forecast concerns for this evening are a period of gusty winds
along with a two to three hour window of showers. Also, while the
growing season is rapidly fading, there will be subfreezing
temperatures in parts of far northern and north central Illinois.
GOES-16 visible imagery has shown clouds spreading rapidly over
the area this mid-afternoon. This will by 4 PM over locations
east of I-57 where red flag conditions had been met with multiple
sites between 15 and 25 percent relative humidity and gusting to
30 mph. While the winds will increase some into early evening, the
fire weather threat will ease due to gradually increasing
relative humidity and the likelihood of showers. So no changes
planned to the Red Flag Warning, but burning is continued
discouraged through the entire evening.
Satellite water vapor imagery is depicting a pronounced upper
wave and attendant upper jet of 100+ kt sweeping across Iowa.
Forcing for ascent ahead of this is shown on satellite with
increasing cloud cooling over the area as well as a growing
shower footprint across Iowa. This forcing will further increase
immediately ahead of the wave and concurrent with a strengthening
surface cold front presently just west of the Mississippi River.
Showers should continue to blossom as these features progress
closer, with the shower timing for the forecast area from 530 to
10 P.M. With the colder air advection sweeping into an inherent
well mixed air mass, there will be potential to mix down some
enhanced gusty winds with any downdrafts. There were a couple
upstream sites along the Iowa-Missouri border to have 40+ mph
winds (even a 51 mph gust at Lamoni, IA), and those were without
showers. The top of the channel on forecast RAP and HRRR soundings
show potential for 40+ mph gusts, and am noting that temperatures
are actually not dropping underneath the cloud layer (i.e.
atmosphere staying mixed). So there is a window of opportunity
for gusts up to near 50 mph.
Behind these showers, the clouds look to clear into early
overnight. With the cold advection, temperatures look to be drawn
down to freezing in the northwest forecast area. Because we are
continuing growing season products at this time, we have issued a
Freeze Warning. Further east and south, frost likely will be hard
to come by given continue winds of ~10 mph overnight.
For Saturday, some stratocumulus may be seen, but otherwise should
be just high clouds with continued breezy westerly winds. Highs in
the lower to mid 50s are forecast by a high majority of guidance
and that lines up well with climatology for 925 mb temperatures of
+1 to +3C.
Issued at 253 PM CDT Fri Oct 14 2022
Saturday night through Friday...
Key messages in the extended forecast period:
1. Well below normal temps expected
- Especially cold and blustery MON-TUE
2. Dry conditions for most of the area next week
- Lake effect showers MON-TUE mainly into NW Indiana
The upper level blocking pattern remains in place for much of the
extended period with troughing across the eastern CONUS and Rex
block across the west. Heading into Saturday night a reinforcing
shortwave moving beneath the upper trough and associated surface
boundary will move across the area into early Sunday morning
turning winds northwesterly. Temperatures Sunday should still
manage to warm into the 50s to near 60. A reinforcing surge of
cold air then moves in late Sunday. This will usher in a cold and
blustery two days with highs only in the 40s and northerly winds
gusting up to 30 mph both Monday and Tuesday.
Expecting dry conditions for most of the area this weekend through
midweek other than some lake effect showers into northwest
Indiana Monday into Tuesday as a shortwave pivots around the upper
low. Also can`t rule out some snowflakes in there but think the
warm lake temperatures should limit this.
Toward the latter half of next week there are signs that the western
ridge may start to break down with temperatures warming back into
the 50s to near 60 Thursday and Friday as shortwave ridging shifts
moves a bit closer to the area.
For the 00Z TAFs...
Aviation Forecast Concerns:
* Brief period of gusty west winds around 35 kts early this
evening, and a period of light rain/showers in VFR conditions.
* Breezy west-southwest winds gust around 20 kts Saturday
Surface low pressure was analyzed just east of KMKE early this
evening, with a trailing cold front trailing across the Chicago
metro terminals into western IL/central MO. Winds are shifting
westerly with the passage of the cold front, and may continue to
briefly gust above 30 kt with and immediately behind it early this
evening before gradually diminishing. While low levels are
initially very dry, a strong mid-level disturbance was providing
sufficient forcing/ascent to saturate the column and produce an
area of light rain/showers, which will linger for a few hours
early this evening before clouds dissipate overnight.
Surface high pressure will build south of the region across the
lower Ohio Valley on Saturday, while another in a series of cold
fronts approaches from the northwest later into the evening.
Surface winds will gradually back from west to southwest through
the afternoon, becoming somewhat breezy again with gusts around 20
kts. Gusts will subside Saturday evening, though southwest winds
should remain near 10 kts ahead of the approaching cold front
which moves in beyond the end of this TAF period. Otherwise, VFR
conditions will prevail.
ILZ012...1 AM Saturday to 8 AM Saturday.
LM...Small Craft Advisory...Winthrop Harbor to Burns Harbor until 4
Small Craft Advisory...Burns Harbor to Michigan City IN until 10
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Area Forecast Discussion
National Weather Service Pueblo CO
247 PM MDT Fri Oct 14 2022
.SHORT TERM...(This evening through Saturday)
Issued at 245 PM MDT Fri Oct 14 2022
1) A Frost Advisory has been issued for Crowley and Kiowa counties
from 3am until 8am Friday morning.
2) A dry cold front will pass through tomorrow, bringing easterly
winds and slightly cooler temperatures for our Saturday.
Relative humidities have fallen into the single digits for most of
the high country, with a lot of the plains already down to near 10%
as well. Winds have began to calm and shift more northerly and
easterly as the pressure gradient relaxes across the region. Not
expecting any cloud cover or precipitation this afternoon, but we do
have a couple of prescribed burns going on in Chaffee and Huerfano
counties, where smoke plumes are starting to become apparent on
visible satellite imagery.
Rest of Today and tonight..
We remain in northwesterly flow aloft as longwave troughing sits
across the eastern half of the country and a low pressure system
begins to push onshore near the southwest coast of California. A
Frost Advisory has been issued for Crowley and Kiowa counties from
3am until 8am Friday morning. Expecting radiational cooling to be
strong on our plains tonight with all of the dry air being advected
into the area today. Downsloping winds will help to keep our
mountain adjacent plains slightly warmer and drier, but expecting
frost to be likely for areas north of highway 50 and east of the I-
25 corridor where dewpoints recover into the upper 20s by around
sunrise. Will continue to monitor eastern Pueblo county and Prowers
county, where frost formation looked more marginal, but still
possible. In the high country, expect overnight lows to be near or
below freezing again tonight.
Deterministic models push a backdoor cold front across our plains on
Saturday morning. The HRRR brings this boundary in between about
10am and noon tomorrow. Models are in close agreement that we will
stay dry behind the front, and winds will quickly become easterly
after its passage. Skies are expected to stay mostly clear tomorrow,
with temperatures rising to near normal for daytime highs. Warmest
temperatures will stay southeast, with Baca and Prowers counties
warming into the upper 70s. Elsewhere on the plains we`ll see highs
in the low to mid 70s, with mountain valleys warming into the 60s
and higher terrain seeing highs in the 50s.
.LONG TERM...(Saturday night through Friday)
Issued at 245 PM MDT Fri Oct 14 2022
1) Cool and cloudy Sunday for most, with precipitation along
southern portions of Colorado.
2) Drier and warmer pattern expected to develop next week for
Saturday Night... The start of the long term period will bring some
active weather to southern Colorado. During late Sunday/early
Saturday timeframe, a short wave trough just to the northeast will
race to east, and is expected to push a cold front southward across
the region, with northerly winds behind it. This is anticipated to
be a dry cold front though, as moisture and surface forcing will be
on the modest side. Given that, dry conditions are expected across
southern Colorado. As for temperatures, despite the cold front,
increasing cloud cover will keep temperatures slightly warmer than
the past few previous nights. The plains will cool into the low to
mid 40s, the mountain valleys will drop into the 30s, and the
mountains will fall into the mid 20s to low 30s.
Sunday... Weather picks up in activity some across the region for
the end of the weekend. Ensemble model guidance, such as the GEFS
and EPS, are in good agreement about the pattern Sunday.
Synoptically, a closed low will slowly trek across New Mexico, just
south of the Colorado state line. This low will bring increased
synoptic ascent and better flow to the region. Given the support
from the low, and stronger orographic forcing from the better flow,
precipitation is expected to develop starting around mid morning and
continue through the afternoon. With that said though, the
aforementioned short wave will confine higher moisture to the
south/southwestern part of the state, particularly along the San
Juan and Sangre de Cristo Mountains. Given the lack of greater
moisture, precipitation will be more scattered in nature. At lower
elevations, winds behind the cold front are expected to become more
easterly during the day, starting in the morning. The easterly winds
will induce persistent surface upsloping during the day. Given these
easterly winds, along with a modest uptick in surface moisture
behind the front, overcast skies are likely across much of the
eastern plains, especially along portions of the southern I25
corridor. Looking at temperatures, a much cooler day is expected
given the cold front and widespread cloud cover. Given this, most
across southern Colorado are expected to be below average throughout
Monday - Friday... For the rest of the long term period, a more
quiet stretch of weather is expected. Ensemble guidance continue
in agreement about the pattern. Starting Monday, troughing out
east and ridging out west is expected to redevelop over CONUS,
with northwest flow over Colorado. As this pattern develops, the
aforementioned low will become ingested into the troughing out
east during the day Monday, and persistent northwest flow is
expected after that. This pattern will bring drier air into the
region, which will lead to low precipitation chances, with the
exception being around the San Juan Mountains Monday as the low
moves east. This pattern will also bring above average
temperatures to southern Colorado, especially for the eastern
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 245 PM MDT Fri Oct 14 2022
VFR conditions are expected at all three TAF sites, KCOS, KPUB, and
KALS. At KCOS and KPUB, winds will continue to remain mostly
easterly this evening, before switching back to northerly overnight.
A weak cold front is expected for Saturday morning, which will bring
northerly and easterly winds for the rest of the day tomorrow. At
KALS, winds will remain light and diurnally driven. Sky conditions
are expected to be mostly clear throughout the period and no
precipitation is expected at any of our TAF sites.
Frost Advisory from 3 AM to 8 AM MDT Saturday for COZ089-095-096.