Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 02/10/23
Area Forecast Discussion
National Weather Service Denver/Boulder CO
227 PM MST Thu Feb 9 2023
.SHORT TERM...(This evening through Friday)
Issued at 203 PM MST Thu Feb 9 2023
Upper trough axis will drift off to the south and east through
tonight, with ridging shifting back into the forecast area on
Friday... leading to a much quieter forecast period. Ongoing gusty
winds across the plains will gradually diminish this evening as
the strongest winds aloft shift out of the forecast area. Much
drier air associated with approaching ridge will also arrive
tonight. This type of setup, with a cold/dry/subsident airmass
aloft is favorable for very cold overnight lows... and it wouldn`t
be surprising to see a site or two in Middle Park drop to around
-25F. It won`t be nearly that cold across the plains, but lows
should tumble into the single digits or low 10s.
A sunny day is forecast for Friday with temperatures warming up a
bit compared to today. Temperatures across the urban
corridor/plains tomorrow will largely be dominated by if you have
snowpack or not. Where little/no snow cover remains, highs should
reach the 40s if not 50F, with mid to upper 30s expected
elsewhere. Winds will remain light through the day.
.LONG TERM...(Friday night through Thursday)
Issued at 203 PM MST Thu Feb 9 2023
An upper level ridge will build over the area on Sat as a strong
storm system is over California. This will lead to a dry day with
warmer temps. Highs across nern CO will range from the 50`s along
the I-25 Corridor with lower to mid 40s across snow covered areas
of the plains.
On Sun, the storm system over California will move into the Baja
region as a weak NW flow develops over the area. In addition a cool
front will move across the plains. Overall, this will lead to
another dry day with cooler temps, over nern CO, as readings
along the I-25 Corridor drop back to seasonal levels.
By Mon, the storm system over the Baja region will eject ENE across
the srn Rockies. The ECMWF is further south with the track versus
the GFS. As a result, the GFS produces some light precip over srn
areas of the CWA, mainly Mon night, while the ECMWF keeps it
further south. For now will keep in a slight chc of precip over
srn areas of the CWA.
Looking ahead to Tue and Wed, a strong upper level trough will
develop over the wrn US and eventually develop an intense closed
upper level low over the Great Basin by late Tue. On Wed, this
system is currently fcst to move eastward across srn CO/nrn New
Mexico on Wed. The ECMWF is further south with the track versus a
more nrn position shown by the GFS. Naturally, depending on the
track, will have a huge impact on snow amounts across the area.
Since this system is nearly 6 days away, there will likely be
several fluctuations in model solutions.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1033 AM MST Thu Feb 9 2023
Main aviation impact will be gusty winds and ceilings hovering
near 6000ft today. Shallow inversion noted on ACARS soundings from
DEN kept gusts at bay for a while, but this has eroded a bit over
the past hour. With cloud cover breaking a bit and some modest
subsidence in the region, we should see more consistent gusts at
the terminals. SCT-BKN cloud deck should continue through the
afternoon, fully scattering out late this afternoon or early
evening.
Wind should switch back to typical drainage patterns tonight and
will remain light and southeasterly tomorrow. No ceiling or
visibility impacts are anticipated on Friday as VFR prevails.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Hiris
LONG TERM...RPK
AVIATION...Hiris
Area Forecast Discussion
National Weather Service Indianapolis IN
1001 PM EST Thu Feb 9 2023
.Forecast Update...
Issued at 1001 PM EST Thu Feb 9 2023
Gusts have continued to subside as expected, although
drizzle/sprinkles have continued to redevelop a bit longer than
anticipated owing to a secondary cold front/surface trough and
broader cyclonic flow over the region. Will carry sprinkles a bit
longer into the overnight, but otherwise the forecast is in
excellent shape.
Previous Update...Issued at 631 PM EST Thu Feb 9 2023
* Will allow wind headlines to expire on schedule at 7 PM EST.
* Gusty winds will continue into the evening hours.
Wind gusts across the area are slowly but steadily beginning their
evening decline as mixing decreases and low pressure continues to
pull away from the area, allowing the pressure gradient to relax.
Gusts up to 40 MPH will remain possible over the next few hours, but
will continue to decrease. Will allow the wind headlines to expire
on schedule at 7 PM EST and replace with an SPS for occasional gusts
30-40 MPH through midnight.
Otherwise, have added a mention of scattered sprinkles over the next
few hours per obs and radar trends. Measurable precipitation appears
unlikely, and sprinkles should come to an end by 10 PM.
&&
.Short Term...(This evening through Friday)
Issued at 252 PM EST Thu Feb 9 2023
- Winds decreasing and Cloudy tonight; Colder
- Clouds linger on Friday
Surface analysis early this afternoon shows deep low pressure in
place over northern Illinois along with a cold front stretching
east into lower Michigan then south across Western Ohio.
GOES16 shows mainly cloudy skies across Indiana, wrapping around the
low and spreading across Central Indiana. Due to the deep low, a
strong pressure gradient remained across the forecast area and winds
were gusting to 40-50 mph. ACARS soundings show 50+ knot winds just
above the cloud level surface. Radar shows a few showers have
developed within the wrap around flow over northwest parts of
Central Indiana. Aloft, water vapor showed a broad trough in place
from the upper midwest to W TX and NM. The upper low was found here
over NE IL, moving NE.
Tonight -
Models suggest the upper low will continue to make progress
northeast along with the associated surface low. However this will
keep broad cyclonic flow in place across Central Indiana through the
overnight hours. The extensive cloud shield is seen to extend west
to western MO and western IA, amid cold air advection. Forecast
soundings through the night remain similar to what we are currently
seeing in ACARS soundings, with lower level moisture trapped beneath
a steep inversion aloft. This lower level moisture is suggested to
persist overnight all while cyclonic lower level flow continues.
Thus we will expect cloudy skies overnight. Any lingering afternoon
rain showers should diminish after sunset as any heating becomes
more limited.
Regarding the wind gusts, the combination of the loss of the (albeit
limited) diurnal heating with the surface low making further
progress northeast and away from central Indiana will result in a
gradual decrease of wind gusts. The ongoing advisories and warnings
should be on track to expire on time if not slightly earlier.
Given the ongoing clouds and cold air advection, overnight lows
should be in the lower 30s.
Friday -
Models suggest the broad trough to the west will be pushing across
the Mississippi valley and into Indiana and the Great Lakes on
Friday. There appears to be some weak forcing with this upper
trough, but the lower levels are not favorably organized for
precipitation. A large area of surface high pressure stretching from
the SW plains to the upper midwest will be building across Indiana.
Cyclonic flow remains in place for much of the day within the lower
levels with a ridge axis remaining west of Indiana. Forecast
soundings remain dry through much of the column, but fail to remove
the trapped lower level moisture until late afternoon. Thus given
these signals, will trend toward a mostly cloudy day with perhaps
some clearing by late in the day. Given the ongoing cold air
advection, will trend highs to the upper 30s and low 40s.
&&
.Long Term...(Friday night through Thursday)
Issued at 252 PM EST Thu Feb 9 2023
Beginning with the large-scale pattern, broad troughing over the mid
CONUS will gradually pinch into a closed cut-off low over the lower
Mississippi Valley. The northern branch of the jet stream meanwhile
reconnects into a quasi-zonal flow regime centered over the US
Canadian border. A second cut-off low develops over the western US
around the same time. What we`re left with is a generally zonal
northern branch with two cut-off lows slowly traversing the lower
CONUS. The second of these, the one over the western states, will
most likely be our next weather-maker.
Friday Night through Sunday
At the surface, high pressure regains control by Friday evening.
Cold air associated with the trough remains, and low temperatures
Saturday and Sunday morning will likely be into the 20s. Light winds
and clear skies should lead to a nice coating of frost for most
places by sunrise each day. The surface high, in the shape of a
crescent as it arcs around the closed low over Georgia, will stretch
from Texas to New Jersey by Saturday evening. No major changes in
sensible weather are expected during this time besides a very
gradual warm up on Sunday afternoon.
Monday and Tuesday
By Monday, the high will be sliding further east as the close low
exits off the coast. Guidance hints at a fast-moving wave riding the
northern stream passing to our north on Monday. This feature may
drag a cold front across Indiana, but with no real arctic connection
any temperature drops will be minimal. Simultaneously, the west
coast closed low now begins to emerge into the Plains states.
Surface high pressure behind the weak front quickly slides to our
east, and combined with the emerging low out west we`ll see MSLP
gradients tighten over the Mississippi and Ohio River Valleys.
Surface winds gain a southeasterly component by Tuesday morning and
a gradual warming trend resumes.
Wednesday and Thursday
Guidance differs with small details be remains in generally good
agreement with the timing and position of the system developing in
the Plains on Tuesday. The overall idea is of a developing surface
low over Kansas on Tuesday which then moves northeastward towards
the Great Lakes on Wednesday. With the system cut off from the
northern branch, no substantial cold air is in place ahead of and
north of the low. Therefore, primary precipitation type should be
rain throughout Indiana - especially with the low tracking to our
north. Rain looks to enter our CWA Tuesday evening or early
Wednesday. Temperatures will be warmer than average as southerly
flow ramps up ahead of the system, which again passes well to our
north.
While all this is going on, another trough begins to dig across the
western states. Guidance maintains decent agreement with this system
as well, so above-average confidence exists regarding another
weather system affecting Indiana by the end of the long range
period. Confidence exists only in timing, however, as models show
various positions and precip types across the region. Guidance
generally brings a surface low southwest to northeast across the
region, and this makes sense given the overall pattern of west coast
troughing with east coast ridging. Details regarding sensible
weather will come down to surface low track and strength, naturally.
Given the warm flow pattern, rain is being held as the predominant
precip type for now.
&&
.Aviation...(00Z TAF Issuance)
Issued at 612 PM EST Thu Feb 9 2023
Impacts:
* Strong wind gusts gradually diminishing overnight.
* Widespread MVFR ceilings most of the period with IFR possible late
tonight.
Discussion:
Strong low pressure over the Great Lakes will continue to pull away
during the TAF period. As this occurs, the relaxing pressure
gradient along with diminished mixing overnight will allow strong
gusts to gradually diminish overnight, with gusts coming to an end
late tonight. Gusts will initially be in the 25-35KT range out of
the west/southwest, declining to around 20-25KT out of the west over
the next few hours, then coming to an end by 09Z. Around that same
time, widespread MVFR ceilings may become high end IFR, although it
will be close and fluctuations are likely.
MVFR ceilings will return during the day on Friday, with ceilings
likely to scatter out toward the end of the day. Winds during the
day on Friday will generally be around 8-12KT out of the northwest.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Update...Nield
Short Term...Puma
Long Term...Eckhoff
Aviation...Nield