Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 10/21/22
Area Forecast Discussion
National Weather Service Indianapolis IN
949 PM EDT Thu Oct 20 2022
.Forecast Update...
Issued at 949 PM EDT Thu Oct 20 2022
Forecast is in good shape this evening. Satellite images show thin
cirrus moving across the area, with more cirrus upstream. Based on
how thin the cirrus is, lowered sky cover some into the early
overnight. Thicker cirrus will move in late during the night, so
left the forecast as is at that time.
Forecast low temperatures look reasonable given the expected sky
cover and lighter winds at times overnight, so made no significant
changes.
&&
.Short Term...(This evening through Friday)
Issued at 247 PM EDT Thu Oct 20 2022
* Red Flag Warning through this afternoon
* Warming trend into the weekend
* Breezy to windy at times
Rest of Today
Now that the mid-level clouds from earlier have generally exited the
region, solar insolation has rapidly allowed boundary layer mixing
to take effect. Recent ACARS soundings out of IND show very dry air
and 30-40kt winds between 925 and 850mb. Efficient mixing and
downward momentum transfer quickly brought gusty winds to the
surface scouring out any residual surface moisture. Dew points
throughout central Indiana have dropped into the lower teens,
yielding RH values between 16 and 22 percent. Additionally,
southwesterly winds between 15-20kt with gusts to 30kts have been
reported early this afternoon. Combined with very dry surface fuels,
between 7-9% across the CWA, critical fire weather conditions are
now present. Given similar soundings upstream in Illinois and
Missouri, the Red Flag Warning will be maintained through 00z.
Tonight
Gusty conditions should die down quickly upon sunset, though
sustained winds may remain elevated as the surface pressure gradient
tightens overnight. Warm air and moisture advection combined with
some wind should prevent low temperatures from being as cold as
recent nights. Lows should stay in the mid to upper-30s, with lows
near 40 in urban areas.
Generally northwesterly flow aloft will take on a more anticyclonic
curvature as a weak ridge moves in from the west. Moisture advection
rounding the top of the ridge has been evident on water vapor
imagery this afternoon across the northern Plains. Guidance
continues this trend as the ridge enters the Great Lakes and
widespread cirrus can be expected to overspread the region after
midnight tonight.
Friday
The weak ridge should flatten by morning into a more zonal flow
regime, with a slight southwesterly component. Lingering cirrus
clouds should dissipate as this happens, leading to a mainly sunny
afternoon. Warm air and moisture advection continue into Friday,
which will mark the beginning of a warming trend for this weekend.
Highs should top out near 60 for most places tomorrow. The tight
surface pressure gradient will remain in place as well, leading to
another gusty afternoon as diurnal mixing resumes. However, given
the increase in low-level moisture, fire weather conditions are not
expected to reach critical levels.
&&
.Long Term...(Friday night through Thursday)
Issued at 247 PM EDT Thu Oct 20 2022
Friday Night Through Sunday.
Above normal temperatures will continue into the weekend with a
strengthening ridge east of the Mississippi and good surface flow
from the Gulf of Mexico. A weak tropical system will slowly travel
up into the Carolinas Saturday into Sunday, but not expecting any
impacts to the weather across central Indiana barring the system
strengthening well beyond even the most aggressive ensemble members.
Conditions will be well above normal, but still below the record
highs of low 80s for this time of the year. Fire weather concerns
will gradually lessen into the weekend with the southerly flow
helping to increase the surface moisture and allow for MinRH values
closer to 30-40 percent. Wind gusts will remain quite strong though
with periods approaching 30 mph at times, so will still have to keep
an eye out for elevated fire weather conditions.
Monday through Thursday.
Conditions then begin to shift going into early next week as a
strong closed low pushes out from the lee of the Rockies and moves
up into the Midwest. There remains a significant amount of model
spread as to how quickly the low exits, but once it does it looks to
quickly travel from the Southern Plains into the Midwest. Leaned
the forecast closer to the GFS/Canadian solution which was a bit
slower and deeper vs the Euro which quickly pushed the low out of
the Rockies and further to the northeast.
Either way, expect a period of rain towards mid week even though
confidence on the exact day remains low. Depending on the final
timing of the system, a few thunderstorms are probable with the warm
moist air out ahead along with a non-zero severe threat with good
model agreement on abundant shear with the instability being more
uncertain. In the aftermath of the system, temperatures will return
closer to normal with highs in the mid 50s and lows dropping to near
40.
&&
.Aviation...(00Z TAF Issuance)
Issued at 639 PM EDT Thu Oct 20 2022
Impacts:
* Gusts up to around 25 knots Friday afternoon
Discussion:
VFR conditions will continue through the period, with mainly some
high clouds passing at times.
Winds will diminish some this evening but will increase once again
Friday, with gusts around 25 mph again Friday afternoon.
Stronger winds aloft overnight will create conditions near Low Level
Wind Shear criteria, but confidence in reaching criteria is not high
enough to include in the TAFs.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...50
Short Term...Eckhoff
Long Term...White
Aviation...50