Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/27/23
Area Forecast Discussion
National Weather Service Columbia SC
801 PM EDT Sun Mar 26 2023
.SYNOPSIS...
Thunderstorms will bring a threat of severe weather today
across much of the forecast area. A front will remain stalled
over the area through Tuesday keeping chances of showers and
thunderstorms in the forecast. High pressure and drier air will
be over the region for Wednesday through Friday with moisture
returning Friday afternoon and showers anticipated for the first
half of next weekend.
&&
.NEAR TERM /UNTIL 8 AM MONDAY MORNING/...
The stalled boundary along the Gulf Coast extending into the
Carolinas has been the axis of thunderstorm activity today as a
small upper impulse has moved over Georgia and South Carolina.
Precipitable water has been well over an inch and a half; much of
central Midlands closer to 1.75 inches. Forcing has dwindled and
instability has weakened. Severe threat has ended for the time
but disorganized convection with some locally heavy rain is
expected through late afternoon. Although MUCAPE values are
still around 500-1000 J/kg south of I-20 thunderstorm coverage
is expected to be limited.
Tonight, at the same time the stationary front attempts to move
north as a warm front, another shortwave will move across
Georgia and South Carolina late in the evening. This will bring
another batch of organized thunderstorms into the area. Guidance
has been poor at timing of convection activity reaching our CWA
but is in very good agreement that best chances of precip will
be in central SC and CSRA. The low level jet max is expected to
move over Georgia just prior to 06z. At this time, surface based
instability will be very limited but some elevated instability
will be around. Any storms overnight will need to be monitored
mainly for hail threat and enhanced helicity southeast of the
LLJ max.
&&
.SHORT TERM /8 AM MONDAY MORNING THROUGH WEDNESDAY/...
A frontal boundary will continue to be the primary forcing mechanism
for convection through Tuesday. The CAMS are showing an area of
showers and thunderstorms moving across The Midlands during the
morning and early afternoon. The boundary shifts southward closer to
the coastal plain late Monday afternoon and night. SPC has the
region in a Marginal Risk of severe weather. 12Z HRRR forecast
soundings show favorable SBCAPE values in excess of 1250 J/KG
and speed/directional shear south of the boundary for the risk
of damaging winds and isolated tornadoes.
Another upper trough approaches the Southeast U.S. on Tuesday which
lifts the frontal boundary northward again. The primary risk of
showers and thunderstorms should be along and south of I-20. High
pressure builds into the region on Wednesday for dry and cooler
weather conditions.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
High pressure will pass across the Northeast U.S. on Thursday and
then move offshore on Friday. A southwest flow aloft will lead to a
warming trend with highs in the mid to upper 70s on Thursday and low
to mid 80s on Friday.
A cold front is forecast to push through the Southeast U.S. on
Saturday with a chance of showers and thunderstorms. High pressure
builds into the region on Sunday for drier and cooler weather
conditions.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Another round of showers and thunderstorms, and associated
restrictions, are expected late tonight into Monday morning. A
line of showers with a few embedded thunderstorms are currently
passing northwest of CAE and CUB. This activity is expected to
stay northwest of the terminals, however. Steadier rain is
expected after about 03z or 04z at all terminals and continue
into late morning or midday. The best chance for thunderstorms
runs from 03z to 07z at AGS and DNL, 04z to 08z at CAE and CUB,
and 05z to 09z at OGB. There is a bit less confidence for
thunderstorms at OGB, though. Winds are forecast to become
southwest and increase after about 10z to 11z. Restrictions
improve and winds diminish after about 18z.
EXTENDED AVIATION OUTLOOK...The pattern remains unsettled
through the middle of the week. Expect periodic restrictions in
ceilings and visibilities.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
Area Forecast Discussion
National Weather Service Dodge City KS
435 PM CDT Sun Mar 26 2023
...UPDATE TO AVIATION...
.SHORT TERM...(This evening through Monday night)
Issued at 1221 PM CDT Sun Mar 26 2023
17Z obs are showing the stratus deck has eroded to areas along the
I-70 corridor and should continue to erode in the next few hours.
In the upper levels a large low is centered near Yellowstone with
a longwave trough situated across Colorado and New Mexico. At the
surface the northerly winds continue due to a large high in the
northern plains and a weak trough is forming along the front range
of the Rockies.
The short term could bring some interesting weather over a short
period of time especially on Monday where the setup looks similar
to what happened on Saturday. Tonight a vort max will break off
from the upper low and move through northeast Colorado into
northwest Kansas. The best forcing appears to arrive during the
night towards morning so most of the precipitation chances were
pushed back into the night time hours with the best chances
occurring in our northwest zones. Upslope flow will also occur as
the wind switch to the east/southeast with the high pressure
center moving towards the Great Lakes. Clouds should increase
through the overnight but with cooler air in place we should still
see temperatures drop into the mid 20s.
Monday as the wave moves through northwest and north central
Kansas the best forcing and chances of rain/snow will be along the
I-70 corridor. A cold front will develop behind the wave and with
good mixing the winds behind the front will increase to 20-30 mph
with gusts over 40 especially as the front just passes. HRRR also
shows a brief turn of the winds to the southwest just before the
cold front and this could lead to a brief 1-2 hour warmup where
temperatures could spike up 10 degrees. Also a pocket of very dry
air roughly from Syracuse to Hugoton could develop and a small
window of high fire danger is possible in these areas roughly in
the late morning to early afternoon. This is what is looking
similar to last Saturday`s setup. Temperatures will also support a
small area of snow from Scott City to WaKeeney as the wave comes
through that could produce a quick 1/2 inch of snow. All that I
have described has been reflected in the forecast grids and I
would imagine the short term grids will need to be closely
monitored Monday with the fast changes as the wave progresses.
Monday night as the wave exits the skies should clear quickly with
the subsidence and winds will die down as high pressure enters
into western Kansas allowing temperatures to cool back into the
teens to lower 20s.
.LONG TERM...(Tuesday through Sunday)
Issued at 208 PM CDT Sun Mar 26 2023
Key message will be the high fire/strong winds/blowing dust threat
for Thursday and potentially Friday.
Tuesday should have a modest warm up as the area of high pressure
slides into Missouri and winds switch back to the south during the
day. A lee side low develops in eastern Colorado as a vort max
approaches which should increase the winds by afternoon and this
will help to clear out the coldest of the air in the lower levels
by late afternoon.
Wednesday presents a temperature forecasting challenge as the
surface low in eastern Colorado approaches northwest Kansas colder
air from Nebraska will intrude and make it as far south as the
I-70 corridor...with the NAM showing the farthest progression
south to highway 50. As a result I lowered the temperatures a bit
from NBM guidance in the north as it looks like all the models
are fairly consistent with a warm to stationary front lining up
somewhere around the I-70 corridor. South of the front should have
strong southerly winds and temperatures warming to around 70
while north of the front it could be a struggle to get into the
50s.
Thursday long term deterministic and ensemble models are in good
agreement of a large upper level low entering the intermountain
west and a deepening surface low in eastern Colorado as a 700 mb
shortwave ejects around the upper low. A strong intense dryline
will develop and make it to south central Kansas by late
afternoon. Latest model trends have the convection from the
dryline more into Wichita`s area so the severe threat looks less
around our jurisdiction at this point. What will happen behind the
dryline is intense mixing and very strong southwest winds and low
relative humidity values which will introduce fire/high wind/and
blowing dust threats for Thursday afternoon. We should also see a
good jump in temperatures all across the area with highs in the
70s to around 80.
Friday as the upper low enters into the northern plains as strong
cold front will push through the central plains and we should have
another day of strong winds throughout western Kansas. With the
upper low in northern Kansas/southern Nebraska we could get enough
forcing to have some wrap around precipitation chances mainly
along the I-70 corridor.
Next weekend looks warmer, dry, and windy.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 429 PM CDT Sun Mar 26 2023
VFR conditions will prevail through early Monday. Light east-
northeasterly winds are expected to develop later tonight as
surface high pressure in the Northern Plains drifts eastward into
the Upper Midwest.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 24 54 22 53 / 20 30 20 0
GCK 23 54 20 52 / 20 40 20 0
EHA 26 55 21 53 / 20 10 10 0
LBL 24 56 20 53 / 10 10 10 0
HYS 24 45 23 50 / 20 50 40 0
P28 28 54 30 55 / 10 10 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Tatro
LONG TERM...Tatro
AVIATION...JJohnson
Area Forecast Discussion
National Weather Service Grand Forks ND
1026 PM CDT Sun Mar 26 2023
.UPDATE...
Issued at 940 PM CDT Sun Mar 26 2023
Clouds are moving in ahead of the shortwave on schedule this
evening. Winds will start to shift north from west to east
overnight, with lows in the single digits above and below zero.
Forecast remains on track.
UPDATE Issued at 626 PM CDT Sun Mar 26 2023
Clouds are moving into the area this evening. This pattern will
continue into the overnight hours ahead of a weak shortwave that
will move through tomorrow. Otherwise, forecast remains on track.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 311 PM CDT Sun Mar 26 2023
Seeing some scattered mid clouds advance southeast into
northeastern ND and northern RRV at mid afternoon. Upstream
coverage of clouds not great, but there is some northwest into
southeastern Saskatchewan all ahead and near a weak 500 mb short
wave moving southeast associated with a surface cold front/north
wind shift. This will drop through overnight and for SE ND/WC MN
Monday AM. A second short wave will move from southern Montana
into southern ND daytime Monday and with it some mid level
moisture and chance of very light snow for areas generally south
of I-94. Dusting at most. Colder air does move in with highs only
in the teens for much of eastern ND Monday...normal highs for
Monday are around 40 in Grand Forks. With forecasts mid teens we
are talking 25 degrees below normal. Trees will be a bit warmer.
A north wind Monday behind the front in the 8 to 15 kt range.
Monday night will see winds diminish in the evening and turn west
or southwest overnight ahead of Tuesday`s front.
For tonight...some potential for patchy fog in SE ND and west
central MN. NBM has some spotty fog development and HRRR does too.
But HRRR has been too aggressive of late. But with NBM showing a
little fog potential felt it was reasonable to go along with ABR
and add some fog near the SD border and northeast toward Detroit
Lakes.
.LONG TERM...(Tuesday through Sunday)
Issued at 311 PM CDT Sun Mar 26 2023
Overview: Temperatures will remain in the 20`s (ND) and low to mid
30`s(MN) throughout the week. Possibly another system impacting at
the end of the work week.
Discussion:
Tuesday the active pattern continues throughout the week.
Tuesday holds onto a week system with a slight (10-15%) chance of up
to a light dusting. While there is some synoptic forcing from the
700-500mb divergence aloft. Only a few pockets of moisture in an
overall dry atmosphere are reflected in guidance. The LREF is a
little bit more generous with a 20% chance up to an inch along with
the NAM deterministic model. Given the high pressure system over the
Northern Plains around that time its more likely we would not
receive anything or receive just a light dusting pending on the
timing.
Temperatures will continue to remain below normal for the end of
this forecast period. The daily highs will fluctuate between the
High teens and Low twenties (ND) low twenties to low 30`s (MN).
Thursday until the end of the forecast period, The Grand/Super
Ensemble is pretty split on our chances for precipitation. The Euro
and Canadian ensembles showing a strong high pressure system over
the region keeping the low pressure system on a more southern track
and not impacting our area. The GFS has the higher pressure system
moving over a little bit later allowing for a more northern track
the low pressure system to take. Both scenarios are supported by the
Fri 00z WPC QPF clusters. The first two clusters are dry, but the
last two leave open the possibility of getting some precipitation.
These last two cluster contain more GEFS variance while the first
two are more Euro and Canadian. NBM probs for 00z-12z Friday are 20-
30% chance for greater than 2 inches, with greater than 4 inches
dropping to less than 20%. The global models aren`t currently
showing any areas of strong temperature advection at the 700mb level
or 850mb to increase forcing. Model guidance is also currently
showing the 925 and 850mb moisture transport for our area cut off
from the gulf as well. There`s still a high degree of uncertainty in
the storm track, strength, and available moisture for the region.
These accumulation amounts and potential impacts should be taken
with a grain of salt as guidance further resolves the system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1026 PM CDT Sun Mar 26 2023
Ceilings will drop overnight into Monday morning to MVFR or IFR
depending on your location (DVL, BJI, and FAR and more likely to
see IFR conditions). Winds will shift to the north and increase to
around 10-15kts sustained Monday morning. There is a slight chance
of an isolated snow shower in the southern RRV (FAR), so added SN
mention Monday morning to account for the possibility. Conditions
will slowly improve back to VFR or MVFR heading into Monday
evening.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...AK
SHORT TERM...Riddle
LONG TERM...MM
AVIATION...AK
Area Forecast Discussion
National Weather Service Glasgow MT
829 PM MDT Sun Mar 26 2023
.DISCUSSION...
EVENING UPDATE:
Forecast is on track. No updates are expected. GAH
AFTERNOON DISCUSSION:
This morning`s fog coverage continues to diminish as visibilities
have been steadily rising since the late morning. Tonight, the
biggest concern freezing fog will be primarily concentrated along
the North Dakota border and locations in the Yellowstone River
Valley and toward Wibaux County. Meanwhile, surface low pressure
over northern Wyoming will continue moving to the east-northeast
through the night. The majority of snow will fall in far
southeastern Montana, though the furthest-most of the snowbands
may graze locations in our southeastern zones as per the past few
HRRR runs. Accumulations are expected to be light, if any.
From Monday, a closed-500mb low will eject from the Gulf of Alaska
toward the US West Coast. Models have good consensus that it will
continue moving south toward southern California and then move
northeast through the midweek. At the same time, an quasi-
stationary upper level low over the Hudson Bay will move a
shortwave around it`s periphery late on Monday, bringing the
forecast area at least a 40% chance of snowfall of 0.1 inches or
more. The latest QPF has increased for this event, leading to
at least a 20% chance for at least 1 inch of snow Monday night,
primarily in locations near Fort Peck Lake and immediately south
of the Missouri River. As per this forecast, accumulations are
expected to remain below Winter Storm Advisory criteria.
From Tuesday through Friday, the low off California will move to
the northeast and remain far enough south to limit precipitation
to Billings` CWA. With the upper-level flow becoming more zonal
through Friday, high temperatures will gradually climb, but remain
below normal. Climatologically for the city of Glasgow, we should
be averaging high temperatures in the 50s by the end of March!
Long range guidance suggests that another trough will move through
the northwest US, indicating that we will continue to keep
temperatures below normal to kick off April (we wish this was an
April Fools joke).
-Enriquez
&&
.AVIATION...
LAST UPDATED: 0230Z
FLIGHT CAT RANGE: VFR-LIFR
DISCUSSION: Tonight, chances of snow showers and freezing fog
from the Missouri River, southward, will bring visibility down
leading to brief IFR/LIFR conditions for KGDV and KSDY through
roughly 15Z. Otherwise MVFR ceilinfgs will be the main control
during this time and afterward through Monday.
WIND: North to northeast at 5-10kt through tonight. Becoming north
to northwest Monday afternoon.
-Enriquez/GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Goodland KS
959 PM MDT Sun Mar 26 2023
.UPDATE...
Issued at 801 PM MDT Sun Mar 26 2023
Main forecast update was to add Kit Carson county Colorado to the
Winter Weather Advisory. Multiple runs of Hi-Res models support a
slight southern shift of a low across eastern Colorado which would
result in a higher threat of blowing snow across Yuma and Kit
Carson counties. The higher snow amounts do favor areas north of
I-70 and western portions of Kit Carson county, but wind gusts
around 35 mph would lead to hazardous driving conditions in
blowing snow, which was the main nudge to include Kit Carson
county. Additional runs interestingly show a few west to east
moving bands of snow impact I-70 across Sherman to Gove county.
MUCAPE, SBCAPE, and MLCAPE all represent a couple hundred joules
of instability which may lead for brief heavy snow showers moving
along the Interstate.
&&
.SHORT TERM...(This evening through Monday)
Issued at 308 PM MDT Sun Mar 26 2023
At the start of the short term period, the latest RAP analysis has
the CWA with a west-southwesterly flow aloft being underneath the
front portion of a broad upper air trough with an upper air low
residing over the ID/WY border on Sunday afternoon. Current surface
observations and satellite imagery shows dry conditions with the
northeastern half of the CWA covered in low clouds with the
remainder of the CWA seeing scattered high clouds moving east-
northeast. Forecast models show a shortwave disturbance moving
through the flow over the CWA as well as a generally westerly flow
over the CWA going into the overnight hours with the aforementioned
low moving more over WY. At the surface, models continue to show an
inverted surface trough over eastern CO this evening allowing for
snowfall chances to begin in the western portions of the CWA
overnight. Not much snowfall accumulation is expected before
midnight in these areas. Overnight lows look to be between the upper
teens and middle 20s.
On Monday, forecast guidance predicts the CWA taking a west-
southwesterly flow aloft again in the morning as the low opens into
a trough which has its axis pass over the CWA overnight. Models also
show another shortwave disturbance passing through the flow over the
CWA during the day. At the surface, a Winter Weather Advisory was
issued for Yuma county as well as the counties along the KS/NE
border starting around midnight MDT going into the night. The
snowfall chances look to increase in both probability as well as
areal coverage throughout the day. Areas within the Advisory may see
snowfall totals up to between 3 and 5 inches with locally higher
possible. Hazardous driving conditions are expected due to the snow
and possible blowing snow in the western portions where gusts up to
35 mph may be possible in the afternoon. Visibility also could be
reduced as snowfall could become moderate to heavy at times. Areas
south of the Advisory may see an inch or two of snowfall possible
during the day with rain possibly mixed in during the afternoon
especially in eastern and southern portions of the CWA.
Precipitation chances look to taper off from west to east during
Monday night. Daytime highs on Monday look to range between the
middle 30s and the middle 40s followed by overnight lows in the
lower teens to lower 20s range.
For Tuesday, the front part of a trailing ridge is forecasted by
model guidance to move over the CWa during the morning with the
ridge progressing eastward throughout the day while an upper air
low moves off the coast near the CA/OR border. At the surface,
warmer air is expected to come in from the south with a surface
low seen over CO during the day. With this setup, there is the
potential for some elevated fire weather concerns in the
southwestern corner of the CWA. Will continue to monitor this.
Also worth noting, models show some gusty winds around 35 kts from
the south in the evening and going into the night into the
southern portions of the CWA as the low moves closer to the CWA.
Tuesday`s daytime highs are forecasted to be between the middle
40s to the lower 50s with the overnight lows in the upper teens to
lower 30s.
.LONG TERM...(Wednesday through Sunday)
Issued at 110 PM MDT Sun Mar 26 2023
For the long term period, near to below average temperatures are
forecasted except for Thursday. Dry conditions are also forecasted
but there could be a few chances for precipitation near the end of
the week.
Wednesday has the area under ridging aloft, but guidance is
suggesting that a cold front associated with the upper low over the
Great Lakes region will push through the area. Guidance continues to
trend cooler with highs mainly in the 40`s and 50`s, but there is
the possibility for 50`s and 60`s due to the ridging and a
developing surface low from the southwest. If the colder air stays
more to the northeast, the warmer temperatures become more likely.
However, even the colder air does stay to the northeast, the
potential for high cirrus clouds may still keep temperatures fairly
capped.
Thursday continues to have the highest potential for impactful
weather with a chance for strong winds, blowing dust and fire
weather conditions. This is due to the next trough moving closer to
the area with the surface low forecasted to be just west of the
area. If this occurs, the locales in the warm sector will see the
potential hazards listed above. Will deterministic guidance is in
fairly good agreement for this kind of setup, ensemble spreads have
me less convinced. This is especially because some of the 500mb
spread has the upper trough pushing through faster which would put
the area on the backside of the low and any surface boundary. This
in turn would still allow for some strong winds, but the blowing
dust threat and fire conditions threat would decrease. Need to see
if deterministic guidance holds steady and if ensemble spreads
narrow the next few days. So in short, the warmer solution would
give most of the area highs in the 70`s with a chance for strong
winds, dust and fire conditions while the cooler solution would
still allow for some strong winds, but decreased dust and fire
weather threats and temperatures in the 50`s.
Whenever the front and low pass, temperatures should cool and there
will be some chances for precipitation. This generally looks to be
on Friday but the aforementioned difference in upper trough timing
will affect what happens. Generally Friday should see cooler
temperatures and some precipitation unless the trough and surface
low stall and deepen (a few ensemble members suggested that). But
with much of the forcing forecasted to be east of the area,
accumulations look to be light.
The weekend is forecasted to see some warming as an upper level
trough is forecasted to move. Temperatures would warm back to near
normal or slightly above. However, with the generally northwestern
flow aloft, a fast moving trough or shortwave may move through and
keep us cooler and bring a chance for precipitation.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 951 PM MDT Sun Mar 26 2023
Next system moves in from the west this evening, bringing MVFR to
IFR ceilings to KGLD a stray snow shower can`t be ruled out in the
vicinity of KGLD before sunrise. A surface low develops across
east Colorado during the day and will move east. KGLD may see a
heavy snow shower with gusty winds up to 30 knots during the
afternoon, so opted for a Prob30 due to the lower confidence,if it
does occur LIFR conditions would be possible in visibility for a
period. Light snow will be common for KMCK but may become heavier
and more convective in nature in the afternoon. Snow should move
out around 00Z Tuesday however with stratus lingering through the
end of the period.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Winter Weather Advisory until 1 AM CDT Tuesday for KSZ001>004.
CO...Winter Weather Advisory until midnight MDT Monday night for
COZ090-091.
NE...Winter Weather Advisory until midnight MDT /1 AM CDT/ Monday
night for NEZ079>081.
&&
$$
UPDATE...Trigg
SHORT TERM...076
LONG TERM...KAK
AVIATION...Trigg
Area Forecast Discussion
National Weather Service Indianapolis IN
923 PM EDT Sun Mar 26 2023
.Forecast Update...
Issued at 922 PM EDT Sun Mar 26 2023
- River Flooding continues
- Isolated light rain showers late this evening and early overnight
Surface analysis this evening shows low pressure in place over NW
Central Indiana. A trailing cold front extended southwest across
central and southern Illinois to southern MO. Radar across the
region shows scattered/isolated light rain showers ahead of the
front, spreading into Central Indiana. Light southerly flow was in
place ahead of the front, with cool northwest winds in place in the
wake of the front. Dew points across the area were in the upper 30s
and lower 40s.
Overnight the front is expected to make progress across Central
Indiana. The showers have been showing diminishing returns. As
daytime heating is lost, access to the shallow CAPE that was
available continues to diminish. Thus as the showers push east late
this evening and early overnight, only light to minimal precip will
be expected.
In the wake of the front, cold air advection begins. Models suggest
the development of stratus with saturation in place within the lower
levels as seen within forecast soundings and time heights. Thus
after precipitation ends, we will just trend toward a cloudy sky.
With cloud cover expect lows in the lower 40s.
&&
.Short Term...(This evening through Monday)
Issued at 248 PM EDT Sun Mar 26 2023
Short term focus is on strong wind gust potential with
diminishing convection moving into northward portions of central
Indiana this evening.
A compact minor vorticity maxima within the westerlies aloft is
currently seen in midlevel water vapor channel imagery over eastern
Iowa. Models have this feature continuing eastward tonight, with
another broader low-amplitude shortwave trough following just to
the south. The initial perturbation has aided in modest low-level
moist advection and an axis of surface-based instability is expected
later this afternoon ahead of its attendant cold front. This
should result in initiation of convection across central Illinois
late this afternoon. Some quasi-supercells may evolve and sustain
given strong midlevel flow contributing to effective shear of
around 50-kts, and shear vectors nearly orthogonal to the front.
The overall magnitude of moisture advection should limit convective
intensity, especially eastward into Indiana. Storms will move out of
the axis of highest instability by early evening when they enter
Indiana. The most organized/quasi-supercell structures may sustain
in nonzero CAPE, but overall trend in intensity should be downward.
The best chance for convective hazards will be earlier in the
afternoon in Illinois where storm-scale augmented strong/severe wind
gusts could occur with the most organized cells. Richer low-level
moisture contributing to greater near-ground buoyancy would be
needed for a more noteworthy tornado threat to our west. Hail may
occur in the most organized cells across Illinois, but even then
should generally be small although potentially a sizable
quantity, given the character of the expected thermodynamic
environment.
As the cold front and band of weakening convection move eastward
into central Indiana this evening, large scale ascent from the
second slightly lower latitude shortwave perturbation may aid in
increasing precipitation coverage slightly. So, we have broadened
and increased precipitation probabilities slightly this evening and
into the night.
The post-frontal air mass tomorrow will be colder but not
substantially, with temperatures generally around 5 degrees below
late March climo (upper 40s to low 50s for maximums). Residual
moisture should support a stratus layer for much of the day
tomorrow.
&&
.Long Term...(Monday night through Sunday)
Issued at 248 PM EDT Sun Mar 26 2023
* Slight chance of light precipitation Tuesday
* Potential for another heavy rainfall event end of next week
* Chance for severe weather late week but confidence is low
* Seasonable temperatures through midweek, warming trend late week
Monday night through Tuesday night...
An upper shortwave within broad longwave troughing across much of
the CONUS could produce light precipitation early in the period.
Confidence in precipitation chances is low due to modest moisture
and overall forcing, but latest CAMs suggest PVA/large scale ascent
ahead of shortwave will be enough to produce some light rain. Colder
air aloft associated with this system should help steepen lapse
rates which may allow some frozen precipitation to mix in. No
impacts are expected with this as accumulation is unlikely. The best
chance for precipitation will be across the south Tuesday
morning/early afternoon when the best forcing/moisture align. This
weak disturbance moves east of the area later in the afternoon with
quiet weather conditions through Tuesday night. Expect near seasonal
temperatures through Wednesday before quickly warming up late week.
Mid-late week...
A more amplified pattern is expected mid-late week as an upper ridge
amplifies across the central CONUS in response to strong warm air
advection. This will lead to a deepening trough across the western
CONUS which will bring more active weather to the region late next
week. Mostly quiet conditions are expected Wednesday with upper
ridging beginning to build in, but a weak cold front may move into
northern portions of the area. Marginal moisture return ahead of the
front and low level convergence may produce isolate showers during
the evening. Slight POPs were added for late Wednesday
afternoon/evening. Rain chances increases significantly towards the
end of the week as a surface low develops and tracks towards the
region. Increasing south/southwesterly flow ahead of this system
will help advect rich gulf moisture northward. Ensembles show
anomalous moisture return across central Indiana with PWAT values
around 200% above normal. This along with increasing dynamics is
expected to widespread rainfall late this week. Guidance generally
suggests the potential for widespread 1-2" rainfall amounts. A
tightening pressure gradient will lead to gusty winds late Friday
into Saturday.
In addition, there is some potential for severe weather with this
system. Confidence in exact details for this event is low as a
large spread regarding timing and intensity of the surface low
still exists between models. The GFS ensemble which favor a more
intense low than the ECMWF, has trended slower (more in line with
the ECMWF) in the most recent runs, which would lead to a less
favorable diurnal timing for severe weather. However, increasing
warm air advection Friday night could help offset this and increase
instability overnight. Strong dynamics and anomalous moisture favor
organized convection, but severe weather potential will be dependent
on how much destabilization can occur Friday afternoon and into the
overnight hours. Model trends will be monitored closely over the
next few days as a lot of uncertainty remains.
Confidence in Saturday`s forecast is fairly low due to timing
discrepancies with the late-week system. Isolated to scattered
showers may linger through the day before dry conditions return
Sunday as the system moves further east. The pressure gradient is
expected to relax late Saturday into Sunday, allowing winds to
diminish. Temperatures should return to near seasonal over the
weekend.
&&
.Aviation...(00Z TAF Issuance)
Issued at 650 PM EDT Sun Mar 26 2023
Impacts:
* Small Chance of showers during the evening
* Cold front will shift winds to northerly overnight
* MVFR stratus predawn through at least late morning
Discussion:
Radar trends show shows and isolated thunderstorms over easter
Central Illinois ahead of an approaching cold front. Diurnal heating
along with shallow CAPE across the area has allowed these to
develop. HRRR suggests progression across the TAF sites mainly
within a 01Z-06Z window, and have included VCSH mention for that.
The showers have been weakening upon approaching the Wabash as dew
points are a bit lower across Central Indiana. Furthermore, upon
arrival daytime heating will be lost, resulting in more unfavorable
conditions for convection. Thus confidence is low.
Behind the showers and cold front, winds will trend northerly and
MVFR stratus is expected to move in. Forecast soundings and Time
heights show saturated lower levels developing overnight within the
cold air advection. These low clouds are expected to persist through
much of Monday.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Puma
Short Term...BRB
Long Term...Melo
Aviation...Puma
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
631 PM CDT Sun Mar 26 2023
.SHORT TERM...
Issued at 153 PM CDT Sun Mar 26 2023
Through Tonight...
Short term focus continues to be on the strong to severe
thunderstorm potential this afternoon.
Surface analysis reveals the warm front is likely approaching La
Salle to Joliet to Hebron or thereabouts. To the north, lake-
enhanced push of cooler air with strengthening northeasterlies is
evident, with temperatures dropping near the lake over the last
hour. Latest thinking is the aforementioned locales represent a
reasonable area for the eventual warm front to stall and set up
shop the next few hours. To the south, surface dewpoints continue
to inch their way into the mid and upper 40s. As mentioned
previously, this is just about as low as we tend to see supportive
of surface-based strong to severe convection and remains an
overall limiting factor in the robustness of the threat today.
That said, fairly cold temperatures aloft (around -9 C at 700 mb)
and steepening low-level lapse rates may somewhat offset this,
combined with the sharp nature of the attendant upper impulse.
RAP forecasts depict a 50 ish knot 700 mb jet beginning to cross
east of the Mississippi River, and this will drive commensurate
increases in effective bulk shear towards 40-45 kts this
afternoon supportive of low topped supercells.
Recent satellite loops show increasing bumpiness/congested Cu
developing with MLCIN continuing to slowly erode. Convection
should be initiating shortly. Based on the latest best guess
where the stationary boundary will set up, the main axis favoring
a brief tornado threat will be essentially about 20 miles or so
either side of I-80. The brief tornado threat may also extend
farther south of the Kankakee River, although more veered surface
winds look to cut down on hodograph curvature to some degree. In
this area, the locally damaging wind threat seems to be primary.
The severe threat should wane after about 6-7 PM CDT with the loss
of heating and instability.
This evening and into the early overnight hours, additional
precipitation should develop with the deformation axis across
northwest Illinois. Thermal profiles will initially support mainly
rain, but a transition to a rain/snow mix or even all snow is
possible after about 7-8 PM. Do have some very minor snow
accumulations in the gridded forecast north of about I-88. Any
accumulations should be relegated to grassy or elevated surfaces,
with precipitation expected to largely come to an end during the
early overnight.
Carlaw
&&
.LONG TERM...
Issued at 153 PM CDT Sun Mar 26 2023
Monday through Sunday...
For the first half of the workweek, we`ll find ourselves in a
zonal/quasi-zonal flow regime with the jet stream and an associated
baroclinic zone positioned near/over the region. After today`s lead
shortwave clears the area, a handful of additional disturbances will
traverse through the Midwest and Great Lakes through mid-week.
The first of these disturbances will be riding the coattails of the
lead shortwave, passing to our south tonight into Monday.
Accordingly, the bulk of the precipitation associated with this
trailing wave should remain south of our CWA. A trailing mid/upper-
level vorticity filament could help induce some spotty showers or
sprinkles along a subtle surface convergence axis in our western CWA
Monday afternoon, though the likelihood of getting any measurable
precipitation out of this appears to be low enough to justify
keeping PoPs capped below slight chance for now. Monday`s highs look
to top out in the 40s across most of our forecast area, though
temperatures may not make it out of the upper 30s in our lake-
adjacent locales with onshore flow prevailing through the entire day.
The next wave is progged to scoot by to our south on Tuesday. The
predominant signal in guidance is currently for the bulk of the
precipitation with this wave to remain to our south once again, so
did not feel compelled to stray from the dry NBM PoPs for Tuesday.
That said, the 15Z RAP and 12Z HRRR do show a slight uptick in UVV
over our CWA right at the tail end of their respective runs, and
this is evidently enough for those models to be outputting some
splotchy QPF in or very near our CWA Tuesday morning, so some
refinements to Tuesday`s PoPs may eventually need to be made if this
signal holds steady and/or gains traction in other guidance.
Then, Tuesday night into Wednesday, a vort lobe will be in the
process of getting dislodged from an upper-level low meandering over
Hudson Bay, and the associated low-level response will likely
involve a cold front getting thrusted southward into the Great
Lakes. Moisture profiles on Wednesday don`t exactly look stellar,
and the bulk of the forcing for ascent should remain displaced to
our northeast, but most available forecast guidance is insistent
that we`ll still get some precipitation as the front swings through
the area, nevertheless. The NBM came in with slight chance and low-
end chance PoPs on Wednesday for much of our CWA, and that seems
adequate for now. Progged thermal profiles show support for
precipitation coming in the form of both rain and/or snow, with the
timing of the cold frontal passage likely to be the biggest factor
in determining which precipitation type is favored and where. Winds
also look to become fairly blustery on Wednesday as the front moves
through the area.
Moderating temperatures are then expected into the latter half of
the week as central/eastern CONUS ridging and western CONUS
troughing establish relatively uninhibited south-to-north thermal
and moisture trajectories. The western trough is eventually expected
to eject northeastward towards the Midwest, guiding a deepening low
pressure system in the same general direction. It`s still too early
to attempt to parse out the finer forecast details for what this may
entail for us locally, but rain showers do look like a good bet late
Thursday into Friday, and thunderstorms could certainly occur as
well if the low takes a more northerly track. Given that this late
week system could be pretty potent and draw up a healthy slug of
moisture to our latitude, we`ll need to keep an eye on potential
threats for heavy rainfall and/or severe weather in the region as
well, particularly on Friday. If the low were to take a more
southerly track, then snow wouldn`t be out of the question either
as the backside of the system passes through, but again, this
system is still too far out to say that this will be the case with
any semblance of confidence.
Ogorek
&&
.AVIATION...
For the 00Z TAFs...
631 PM...Forecast concerns include...
Low mvfr/possible ifr cigs tonight.
Wind directions this evening.
Chance of showers this evening.
Isolated showers will be possible this evening across the Chicago
terminals, but the thunder threat has shifted east. There may
still be an isolated thunderstorm with the activity across
northwest IL early this evening, but this activity is expected to
generally lift northeast this evening. There may be some snow that
mixes with this rain across northwest IL and may switch over to
snow at times. Confidence is fairly low but did include tempo snow
at RFD this evening. Once this activity ends later this evening,
the rest of the period is expected to be dry.
Low pressure over central IL currently will move east this
evening. Northeast winds are expected to become northerly this
evening and likely shift north/northwest for a few hours. Only
medium confidence for wind directions this evening with directions
expected to go back to north/northeast late this evening and
overnight. Wind speeds may increase some toward daybreak with some
gusts possible through mid morning.
Low confidence for cigs tonight. Much of the guidance shows low
mvfr or ifr cigs quickly spreading/developing across northern IL
this evening. Maintained 1kft cigs tonight but trends will need to
be monitored and changes are possible. These lower cigs are
expected to scatter out mid/late Monday morning with generally skc
expected Monday afternoon/evening. cms
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...LMZ740-LMZ741-LMZ742...1 AM Monday to 3
PM Monday.
Small Craft Advisory...LMZ743-LMZ744-LMZ745...1 AM Monday to 7
PM Monday.
&&
$$
Visit us at weather.gov/chicago
Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/NWSChicago
www.twitter.com/NWSChicago
www.youtube.com/NWSChicago
Area Forecast Discussion
National Weather Service Pocatello ID
1000 PM MDT Sun Mar 26 2023
.UPDATE...Winter Weather Advisories have been allowed to expire.
More significant shower activity continues in the south central
highlands.
Messick
&&
.PREV DISCUSSION... /issued 143 PM MDT Sun Mar 26 2023/
SHORT TERM...Tonight through Monday Night.
The broad area of low pressure that has essentially been stalled out
over us will finally begin to shift eastward today and move out.
Snow showers will continue working their way gradually southward
through the rest of the evening and taper off overnight into Monday
morning. Hi-res models have struggled with this system so far, as
the NAM catches the snow up north better while the HRRR and WRF
catch parts of the snow we`ve seen through the Magic Valley and
Snake Plain so far today better, leaving a bit of a mess for us to
put together coherently. They tried to show the set up this band of
snow in the Snake Plain and Magic Valley in yesterday`s runs, but
then kept it moving south, whereas we`ve seen it sit and stall out
instead. These snow showers will continue through the afternoon
and begin to lose some steam around/just after sunset. As far as
additional snow totals, there is a 20-40% chance of at least an
additional inch of snow through the Snake Plain and Magic Valley
by Monday morning. Overall, we`re looking at another half inch to
inch and a half through most of the Snake Plain and Magic Valley.
However, there is about a 15-30% chance of 2 to 3 inches of
additional snow from near American Falls to near Burley and
southward to Malta, Rockland, Holbrook, and the state line. At the
higher elevations, there is a 30-50% chance of at least an
additional 4 inches of snow up in the Central Mountains,
particularly in the Lost River Range and White Knob Mountains,
over to the east in the Centennial Mountains, and farther south in
the South Hills, Albion Mountains, and Sublette Range. While some
of the mentioned mountain peaks could see more than 4 inches,
there is a less than 20% chance of at least 8 inches of snow.
Wind gusts so far today have been 20-35 mph in the Magic Valley and
lower Snake Plain, when combined with the snow has briefly dropped
visibility to near 1 mile at times. Winds will stay breezy through
the afternoon, but drop off quickly after sunset in the lower Snake
Plain while hanging on into tonight in the Magic Valley.
Monday will be a much quieter weather day as a weak ridge builds in
over the area for the day. It will start off chilly temperatures in
the low to mid 20s in the warmest areas and more single digits to
low teens as you head north. Patchy fog will also begin to develop
late tonight into early Monday morning once the snow has wrapped up
and the wind speeds decrease, impacting areas from the Magic Valley
into the Snake Plain and Arco Desert, and even into the Teton
Valley. By Monday afternoon most of the Magic Valley and Snake Plain
will warm into the low to upper 30s with everyone else in the mid to
upper 20s. Moore
LONG TERM...Tuesday through Sunday. The models and cluster
forecasts continue to trend slower/father west with the storm
arriving midweek. There will be an increase in moisture Tuesday, but
the push is toward drier especially outside of the central
mountains. That trend shows up somewhat in our latest Blend of
Models forecast, but it appears slower in catching up with this
trend. Right now, it only looks like a couple of inches of snow
likely for the Sawtooths/Boulders/Pioneers/White Clouds. The bulk of
the precipitation still falls on Wednesday and Thursday. The concern
continues to be with southerly flow ahead of the low, allowing for
another warm up, and the potential for snowmelt and rain on snow. It
looks like there will be widespread afternoon temperatures at/above
freezing in the 6500-7000ft range and lower. This will push lowest
elevations to rain during the day and at least a slushy/melting mix
at midslopes during the day. All forecasts point to lowest
elevations at best seeing at most a couple of inches, and most
likely less than an inch. Probability forecasts also show a limited
potential of 4"+ (20-30%) at midslopes. For higher elevations, snow
amounts over 6" fall into the 40-50%, except for the Bear River
Range, eastern highlands and Albion Mountains where probability
forecasts indicate 6-12" possible with only a 10-30% of more than
that occurring. Switching over to rainfall/melted snow amount
potential, where 0.10-0.30" will be likely at/below 5500ft. In that
5500-7000ft range, those amounts hit the 0.20-0.50" range with a 40-
60% chance of over 0.50". Above 7000ft, 0.40-0.90" is possible with
under a 30% chance of over 1"...except for the Bear River Range,
where those percentages are 45-55%. There will be a "lull" Friday
into Saturday as weak high pressure builds in briefly. The next
storm arrives sometime next weekend. With low and mid elevations
experiencing more temperatures above freezing, rain and snow will
again be on the horizon. Keyes
AVIATION...We continue snow and snow showers across eastern Idaho
this afternoon. This will continue well into the evening, when we
will lose the heating of the sun...and the most intense showers
end. There will be some pockets of light snow overnight and Monday
morning, with instability showers confined to the mountains
during the afternoon. As we`ve seen with all of the recent rounds
of snow, conditions at VFR where and when showers aren`t
occurring...dropping to IFR/LIFR with the heaviest activity when
it`s directly impacting a particular airport. We are keeping
MVFR/IFR ceilings in place overnight/Monday morning in the wake of
any snow and high pressure developing. We should see improving
conditions at BYI, PIH and IDA later in the day. With those
mountain showers in play, SUN and DIJ (especially the latter) non-
VFR weather is certainly possible. Keyes
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Raleigh NC
920 PM EDT Sun Mar 26 2023
.SYNOPSIS...
A front will remain stalled out over the Carolinas through Tuesday,
bringing occasional periods of unsettled weather. The front will
finally push to our south early Wednesday, with high pressure to
follow for Wednesday through Thursday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 920 PM Sunday...
Similar to the afternoon update, the boundary remains across
southern counties. Moisture in generally is streaming north, causing
rising dewpoints and some fog to develop in advance of rain moving
in overnight. With the evening update, have slightly slowed down the
arrival of rain. Forecast rainfall amounts remain relatively
unchanged, although the last few runs of the HRRR show a tightening
gradient in rainfall, with much lower rainfall totals along the
Virginia border. Previous discussion follows.
As of 330 PM Sunday...
The surface boundary has moved little over the last several hours,
still stretching across the southern Piedmont, Sandhills, and
central Coastal Plain, with dew points in the 40s and 50s to its
north and 60s to its south. The mid-level perturbation that
generated the showers and storms across the region today will
continue to move east and offshore. The widespread clouds and
precipitation have stabilized the air mass, so little in the way of
additional thunder/lightning is expected before the showers exit the
Coastal Plain in the next couple hours. A brief dry period is then
expected into the evening, before the next mid-level perturbation
currently generating an area of intense convection over eastern TX
approaches from the SW along the front. Thus expect precipitation to
spread in after midnight, with the heaviest exiting the Coastal
Plain after about 12z. The disturbance looks to track a bit farther
north than today`s system, meaning rainfall amounts should be higher
for more of central NC, and high-res models show a widespread area
of showers, locally heavy. PW values will be as high as 1.5-1.75
inches in the south and east (150-200% of normal) and there will be
a strong SW 850 mb jet as high as 40-60 kts. Thus while average
rainfall amounts are expected to be in the half inch to an inch
range, locally higher amounts will be possible, and some localized
urban and poor drainage flooding can`t be ruled out. Shear will
certainly be there (0-6 km shear of 50-60 kts and 0-1 km shear of 20-
30 kts), but similar to last night, one limiting factor will be the
relatively meager instability. MUCAPE looks to be around 500 J/kg at
most, and model soundings again look stable near the surface, with
hardly any SBCAPE and some SBCIN. So similar to last night/today,
some thunder will certainly be possible but not expecting widespread
severe weather. The main threat will again be hail, but an isolated
damaging wind gust can`t be entirely ruled out. Some patchy fog will
also be possible tonight, especially in the late evening before the
rain arrives. Low temperatures will range from lower-50s in the far
NE to lower-60s in the far south.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 230 PM Sunday...
Isentropic ascent will exit north Monday morning as the warm front
lifts towards VA. Some showers may linger across the Coastal Plain
and northern Piedmont by mid-morning, then radar activity will
diminish for a few hours. Another broken line of showers/isolated
thunderstorms may develop in the afternoon/evening as a cold front
sags southeast across the region while a surface low lifts NE from
the TN Valley along Blue Ridge. While strong storms are not expected
at this time, there may be enough instability as the front moves
into a more favorable environment southeast of the Triangle. 0-6 km
shear values are high at 50-60kt, with 0-1km values only around 15
kt, however moisture will be more limited and concentrated closer to
the coast. Conditions will dry out and skies temporarily break up
overnight. Highs will range from the mid-70s N to low 80s S, with
lows in the mid-40s N to low 50s S.
While there is just a slight chance of a shower Tuesday afternoon,
there will be a better chance of a shower during the overnight
hours. Behind Monday`s cold front, highs will only be in the 60s on
Tuesday, and lows will be in the upper 30s and 40s.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 215 PM Sunday...
Wed-Thu night: Rain chances are expected to linger into early Wed as
the mid level shortwave trough and corresponding weak fast-moving
surface trough move over and off the Mid Atlantic and Northeast
coast, followed closely by a polar stream shortwave trough scraping
across the St Lawrence late Sat. We`ll be well into the cooler air,
with the synoptic front well to our S and minimal moisture influx
availability, so any rain amounts will be light. Otherwise, surface
high pressure will build from the Mid Miss Valley E over the Mid
Atlantic region before pushing offshore Thu night. Expect dry
weather with slightly below normal temps Wed, but modifying Thu as
mid level ridging moves in from the W.
Fri-Sun: Deep longwave troughing over the Rockies early Fri will
track to the Midwest by Sat morning and across the Great Lakes to
New England by Sun morning, before it and its trailing trough push
off the East Coast late Sun. Deterministic models are fairly close
on timing but exhibit wide variation in strength/amplitude as it
reaches E NOAM. The surface high pushing offshore early Fri will
allow the surface front to our S to retreat back northward through
NC as a warm front, with a chance of showers and thunderstorms
mainly over the N and W CWA Fri, areawide Sat/Sat night ahead of the
front, and mainly SE on Sun. Expect much above normal temps Fri/Sat
then near normal temps Sun (normals in central NC are about 65-70
for highs and mid 40s for lows). -GIH
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 800 PM Sunday...
TAF period beings with VFR conditions for a few hours until adverse
aviation conditions envelope the area. Widespread showers and
thunderstorms have developed over GA and SC and will move northeast
into central NC after midnight bringing threats for erratic gusty
winds along with IFR/LIFR vsby and cigs. Ahead of this area of
convection, areas of fog and low stratus will be possible at
RWI/RDU/FAY and likely persist until showers/storms move over the
terminals, with greatest confidence at RWI. Showers and storms will
move east of all terminals between 13-16z Monday morning with a
return of VFR conditions to all terminals Monday afternoon resulting
in westerly winds gusting between 15-20kts, latest at FAY and RWI. A
front will bring a northwesterly wind shift and a slight chance (15-
20%) of isolated showers/storms late monday afternoon into the early
evening hours.
Looking beyond 00z Tuesday, nwly winds will continue to back to nly
behind the frontal passage and exiting showers and isolated
thunderstorms. Another round of sub-VFR conditions will be possible
late Tuesday into Tuesday night as rain overspreads central NC.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Green/Danco
SHORT TERM...JJT/Green
LONG TERM...Hartfield
AVIATION...Swiggett