Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/13/24
Area Forecast Discussion
National Weather Service Goodland KS
735 PM MDT Fri Apr 12 2024
.KEY MESSAGES...
- Red Flag Warning in effect for several counties south of I-70
Saturday.
- Blowing dust possible with critical fire weather conditions
likely Monday.
- Strong northwest winds and heightened threat for blowing dust
Tuesday.
- Near critical fire weather conditions south of I-70 Wednesday.
&&
.UPDATE...
Issued at 729 PM MDT Fri Apr 12 2024
Overall forecast remains on track with little changes. Am
watching the potential for some perhaps some smoke to move into
eastern portions of the area (Graham/Norton counties) overnight
and into the morning hours from prescribed burns across Central
Kansas today. The HRRR Near Surface Smoke does indicate some
higher concentrations which may lead to some smokey smell for
some in the morning hours before the nocturnal inversion
dissipates. Also am seeing some signal for brief gusty winds
perhaps around 50 mph with any virga or showers that may
develop during the afternoon hours Saturday as DCAPE looks to be
around 1100 j/kg with inverted v soundings. If this were to
occur the relative favored area would be along and north of
Interstate 70.
&&
.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 235 PM MDT Fri Apr 12 2024
Tonight...mid and high level clouds move across the area from
southwest to northeast. There is a sliver of weak elevated
instability with this batch of clouds, however not enough at this
time to support a precipitation mention. Low temperatures are
forecast to be in the lower to middle 40s. A few readings in the 30s
are possible in the vicinity of the Republican River valley where a
period of light winds are expected.
Saturday-Saturday night...weak/broad upper level ridging will be
over the area, ahead of a closed upper low, forecast to move into
Nevada/central California by 12z Sunday. Southwest to northwest
winds of 10 to 20 mph are expected during the day with gusts up to
30 mph. Overnight, west to northwest winds around 10 mph are
currently forecast. High temperatures are forecast to range from
around 79 degrees in Flagler to 90 degrees in the Norton and Hill
City areas. Record/near record high temperatures are possible in
Hill City (92 degrees set in 2023), Colby (87 degrees set in 1936),
Tribune (88 degrees set in 1946) and Yuma (83 degrees set in 2003).
Low temperatures are forecast to be in the lower 40s to around 50.
Sunday-Sunday night...as the upper trough slowly moves east into
Utah by 12z Monday, south to southeasterly surface winds slowly
develop and increase through the day with the higher speeds over far
eastern Colorado. Overnight, occasionally breezy southeast winds are
currently forecast. The current forecast is dry, however,
GFS/ECMWF/GEM 700-500mb relative humidity show a disturbance moving
northeast across the area during the time of peak heating, possibly
supporting some slight chance pops for showers and maybe a
thunderstorm. Something we`ll need to watch for. High temperatures
are forecast to be in the lower 80s to around 90. Record/near record
high temperatures are possible in Goodland (88 degrees set in 2017
and previous years). Low temperatures are forecast to be in the
lower 40s to lower 50s.
Monday-Monday night...this mornings GFS/ECMWF/GEM/GEFS models move
the upper low into central Colorado by the end of the day then over
the Tri-State area overnight.
Currently, southeast to southwest winds gusting 35 to 50 mph are
anticipated during the day. Locally developed blowing dust/dust
storm thresholds are being met using the reliable GFS model,
favoring locations either side of a line from Tribune and Leoti
northeast to Trenton and McCook in the 21z-00z timeframe. GEM model,
which also does well, remains just a bit lower on the needed wind
speeds of at least 43kts in the 0.5-1km layer but its axis of these
winds is in line with the GFS. Overnight, winds gradually switch to
the northwest for most of the area behind the developing surface
low.
Regarding precipitation chances, there is a large dry slot being
advertised in the 850-500mb layer from the GFS/ECMWF/GEM models
which doesnt support much if any showers/thunderstorms during the
day. Shower/thunderstorm chances do increase overnight. Cant
completely rule out a few severe storms during the evening hours,
mainly east of Highway 27 if at all.
High temperatures are forecast to be in the upper 70s to upper 80s
with low temperatures in the 40 to 50 degree range.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
Issued at 205 PM MDT Fri Apr 12 2024
For Tuesday, guidance continues to shower the surface low exiting
the area and moving off to the east with the advancement of the
upper trough. The issue is that ensemble guidance still shows a
variance in track and speed of progression. Most of the difference
is related to speed of progression which leads to two different
outcomes. First, a slower progression that keep the low over around
Highway 283 by midday would be more likely to lead to a higher
impact scenario. In this case, the low`s tight pressure gradient
would be over the area and bring the potential for high winds
(sustained around 30-40 mph and gusts around 45-65 mph). It would
increase the chance for precipitations as the area gets wrap around
moisture and showers/storms, but blowing dust could still form ahead
of the precipitation. If this occurs, a wall of dust could be
possible ahead of the precipitation as precipitation forms over
Eastern Colorado and advances east with the surface low. The other
scenario would be the case hinted at by the ensemble solutions where
the upper and surface low move well east of the area by the midday
hours. With this precipitation chances would be much lower and
confined more to Highway 83 and east. The winds would be gusty
(likely 20-30 mph gusting 30-50 mph), but not much of a hazard. The
blowing dust potential would also be very low with the weaker winds
and probable lower lapse rates. currently am leaning towards the
second, faster solution with ensembles being fairly consistent in
the fast track for a few days now. Chance for the higher impact
scenario is around 30%. Temperatures are forecast to be cooler, but
how much will depend on the cloud cover and cold air advection. In
most cases, temperatures are forecast in the 60`s and 70`s.
Wednesday, guidance splits on whether or not a broad trough takes
hold over most of the Central CONUS, or if some ridging occurs ahead
of another upper low that will swing through Thu-Fri. If the broad
trough forms, expect a mild day with temperatures near average in
the mid to upper 60`s. If the ridging occurs, chances increase for
70`s and even some 80 south of Highway 40. Precipitation looks to be
unlikely for either upper pattern.
Thursday and Friday, look to be under the influence of an upper low
or broad trough. In either case, below average temperatures are
forecast in the 50`s and 60`s (though temperatures could be warmer
Friday if the upper pattern is not a broad trough). There could be a
few chances for some showers, but nothing noteworthy or high chance
at this time.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 451 PM MDT Fri Apr 12 2024
LLWS looks to impact each terminal through the period with KMCK
being impacted first then KGLD. Winds begin SSE then veer to the
WSW through mid morning Saturday. A few hours of gusts up to 25
knots looks to occur at KGLD then becoming a more sustained 15
knot wind through the area. Winds at KMCK look to remain lighter
due to a weaker pressure gradient vs a more taut gradient over
the KGLD terminal.
&&
.CLIMATE...
Issued at 648 PM MDT Fri Apr 12 2024
With some locales possibly coming within a few degrees of near
record highs on Saturday, April 13th, here is the list of records
for this day:
Goodland, KS........90F in 2006
McCook, NE..........92F in 1936
Burlington, CO......87F in 2006
Hill City, KS.......92F in 2023
With some locales possibly coming within a few degrees of near
record highs on Sunday, April 14th, here is the list of records
for this day:
Goodland, KS........88F in 2017
McCook, NE..........92F in 1940
Burlington, CO......90F in 2006
Hill City, KS.......94F in 2003
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Red Flag Warning from 11 AM MDT /noon CDT/ to 7 PM MDT /8 PM
CDT/ Saturday for KSZ027-028-041-042.
CO...Red Flag Warning from 11 AM to 7 PM MDT Saturday for COZ254.
NE...None.
&&
$$
UPDATE...Trigg
SHORT TERM...99
LONG TERM...KAK
AVIATION...Trigg
CLIMATE... Trigg/Vincent
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1135 PM EDT Fri Apr 12 2024
.SYNOPSIS...
More showers are expected into this evening as a cold front
pushes through the area, and although a brief downpour is
possible, overall additional rainfall amounts will be limited.
Showers will linger into Friday, ahead of another front. Drier
and warmer conditions return for Sunday. High pressure gradually
builds in early next week with partly to mostly sunny skies and a
warming trend. Cooler conditions with mainly rain expected late
next week as low pressure develops to our south.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
Update...Minor changes to reflect the latest observational
trends. Clouds and fog are clearing quickly...so I have removed
much of the fog except for around Penobscot Bay for the next
several hours.
Previous discussion...
Impacts:
*Convective showers associated with a cold front may aggravate
ongoing snowmelt flooding in the White Mountains early this
evening, but are not expected to significantly add to totals.
Widespread rain has moved out of our forecast area, but
scattered showers continue in it is wake as the area remains
under broad cyclonic flow. Therefore, the Flood Watch has been
cancelled, but runoff and snowmelt continue and so small stream
and river rises will as well. For this reason, areal Flood
Warnings and Advisories remain in effect across the north.
Confidence is increasing in some convective
showers/thunderstorms moving up the Connecticut River Valley
around 5-6 PM ahead of a cold front. Latest HRRR runs suggest
available surface based CAPE is only around 300 J/kg so wouldn`t
expect anything rising to the level of severe, but these
showers could contain some graupel or small hail as well as
brief heavy rain. Should these storms pass over the White
Mountains they may aggravate the flooding situation there, but
would not add any significant totals. Elsewhere instability is
limited by the onshore flow, so any storms should be confined to
western New Hampshire.
Patchy fog remains in the forecast through tonight as dewpoints
remain elevated subsidence behind the cold front may lock in
some boundary layer moisture, however the front may also scour
out a lot of that low level moisture, and give us a clearer
night. Either way, low temperatures look to bottom out in the
40s area wide.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY/...
Chances for rain showers will continue Saturday as the area
remains under broad cyclonic flow and a secondary cold front
sweeps through. Skies will remain mostly cloudy with highs in
the low to mid 50s across much of the area. The aforementioned
front will work to clear things out south of the mountains, but
upslope snow showers look to continue across the higher terrain
through the overnight hours with light accumulations possible. A
period of breezy winds, 20-25 mph, is also likely in the wake
of the front and as low pressure makes its final departure to
the north. Low temperatures Saturday night look to be pretty
uniform as cold air advection cools northern zones into the
lower 30s and mostly clear skies help areas to the south cool
into the low 40s.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Current 500 MB double omega block across NOAM mid latitudes and
surrounding oceans, does start to weaken and flatten a bit a
bit later this weekend, but troughing stays nearby through the
week, although, we will be under W-NW zonal flow early next week
which should allow for 2 or 3 mostly dry days in the period.
For the most part temps run near to a little above normal
through the period. Late next week the chance for a steadier
rain returns as 500 MB troughing shifts in from the west.
Sunday will feature a bit of a break with partly sunny skies as
a weak ridge move across the area in the morning. Clouds are
likely to increase in the afternoon, with some showers possible
late in the day, especially across NH. It will be mild with
highs around 50 in the mtns to 55-60 in the S. The best chance
for showers across the region will be Sunday evening, as a weak,
and fast moving 500 MB wave moves through. Showers will be
light, and most of the CWA should see at least some clearing by
daybreak. Lows range from the mid 30s to the 40s, N to S.
As we transition to more zonal flow at 500 MB on Monday, warmer
air will move in but still will see some clouds as we shift
away from cyclonic flow aloft. So, partly sunny covers it, but
it will be a bit warmer with highs mid 50s in the mtns to low
60s in the S. It’ll be a little breezy as well with W wind gusts
to 20-25 mph. As the sfc high builds to the W Monday night, it
will clear out, but should enough flow to prevent widespread rad
cooling, but the sheltered mtn valleys will likely decouple,
and mins range from the low 30s in the mtns to the upper 30s in
the S. Tuesday looks mostly sunny and even warmer, as sfc high
crosses into the region with highs mid 50s in the N to mid to
upper 60s in the S. WE could still eek out a decent Wed, with
clouds moving in during the afternoon, although will see more
onshore flow developing, especially near the coast, so while
highs may climb into the low to mid 60s in the srn half of NH,
they will be limited to the 50s obs the coast and in in the
mtns.
As the ridge moves out Wed night into Thu, upper level trough
will stretch across the NE from W to E, and this bring the
potential for mainly rain across the region, potential in
several rounds Thu into Fri.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Low ceilings continue into tonight with some
clearing likely along the coast as low pressure continues to
move northward out of the area. However, patchy fog may develop
in these areas as dew points remain elevated. Ceilings lower
again as another cold front sweeps through Saturday afternoon.
This front will help to improve conditions back to VFR overnight
Saturday, but will also keep Saturday night on the breezy side
with westerly gusts to 20 kts.
Long Term...Some tempo MVFR conds are possible in SHRA late
Sunday into Sunday evening, but should see VFR for the most part
Mon-Wed.
&&
.MARINE...
Short Term...Southerly gale force wind gusts continue through
this evening before diminishing overnight. Conditions will stay
hazardous to small craft through early Saturday morning, but
winds will be diminishing throughout the day. A cold front
crosses the waters Saturday night shifting winds westerly. This
will also help to diminish seas, but they will remain in the 5-8
ft range through the overnight hours Saturday.
Long Term....SCA’s will likely need to be
continued Sunday into Monday, with seas staying in the 4-6 ft
range outside the bays, and borderline 25 kt gusts. Conditions
eventually subside to sub-SCA criteria Tue into Wed.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 4 PM EDT Saturday for ANZ150-152-
154.
Small Craft Advisory until 6 AM EDT Saturday for ANZ151-153.
&&
$$
NEAR TERM...Legro
Area Forecast Discussion
National Weather Service Northern Indiana
720 PM EDT Fri Apr 12 2024
.KEY MESSAGES...
- Very warm Sunday through Wednesday with highs well into the
70s.
- There is a marginal risk of severe thunderstorms Sunday
afternoon toward the Indiana and Ohio state line.
&&
.DISCUSSION...
Issued at 248 PM EDT Fri Apr 12 2024
Wind gusts have just begun topping 40mph this afternoon, with Knox
recording a 43mph gust. RAP forecast guidance suggests the surface
low and low-level wind field may strengthen yet this evening.
Decreasing cloud cover can improve our mixing, but even so, upstream
observations are closer to 40mph than 45-50 mph. So, will somewhat
hesitantly let the wind advisory ride as-is. Rain showers have
sprouted nicely off the lake and in the vicinity of vort max as seen
on water vapor imagery. This diurnal activity will end around
sunset; same for the showers noted across Wisconsin as of this
writing.
Aside from a chance of thunderstorms Sunday, a beautiful weekend is
on deck. A swirling upper-level low is replaced by high pressure
centered over the Southeast US and a ridge aloft slowly builds.
Highs near 60 on Saturday (approaching 70 toward Monticello) give
way to widespread 70s Sunday. However, a low streaking through the
Great Lakes will send a weak cold front through in the afternoon.
This will result in plummeting temperatures lakeside as
northwesterly wind sets in. This cold front could be the focus for
isolated thunderstorms toward the IN-OH state line. Here,
instability is marginal (near 500-1,000 j/kg), but dew points in the
upper 50s and shear near 40-50 knots are appropriate for the
highlighted marginal risk. Forecast soundings show a cap near 5,000
ft; something the cold front might overcome. I`ll hold steady with
only a 20% chance or so due to very limited coverage on forecast
guidance.
This is a weak cold front indeed as high temperatures quickly
rebound Monday back into the 70s. This, as 500mb heights rise in
response to a deepening trough over the west. By midweek, a surface
low moves through the Midwest bringing more rainfall and a risk of
severe weather to Illinois and western Indiana. Forecast rainfall
ranges notably at this time.
In the wake of this low, a second is quickly on its heels to end the
week. This brings notably colder air to the region; a real bummer
following a week in the 70s.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 720 PM EDT Fri Apr 12 2024
Rain showers associated with a passing midlevel vort max and
very cold temps aloft will taper off within the next few hours.
No impacts to the terminals are expected with VFR conditions
persisting and light sprinkles at best. Winds will also continue
to diminish with the loss of daytime heating. Clear skies
anticipated on Saturday with a steady WNW wind (a few gusts of
20-25 kts possible, especially at KFWA).
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Wind Advisory until 8 PM EDT this evening for INZ005>009-014-
017-018-104-116-204-216.
OH...Wind Advisory until 8 PM EDT this evening for OHZ001-002-004-
005-015-016-024-025.
MI...Wind Advisory until 8 PM EDT this evening for MIZ078>081-177-
277.
MARINE...Small Craft Advisory until 5 AM EDT Saturday for LMZ043-046.
&&
$$
DISCUSSION...Brown
AVIATION...AGD
Area Forecast Discussion
National Weather Service Jacksonville FL
856 PM EDT Fri Apr 12 2024
...New UPDATE...
.UPDATE...
Issued at 852 PM EDT Fri Apr 12 2024
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
Just minor tweak to the temps and dewpoints tonight, with a clear
and seasonably cool rest of the night in store. There will be
enough of a pressure gradient tonight with departing low pressure
over the Atlantic and high pressure moving in to keep some light
breezes around, and therefore limit any significant radiational
cooling inland. Even still, generally upper 40s to low 50s
expected, except at the immediate coast and St. Johns River areas.
&&
.NEAR TERM...
(Through Tonight)
Issued at 230 PM EDT Fri Apr 12 2024
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
A pleasant day continues but with breezy westerly winds near
15G30mph rest of the afternoon and early evening. Temps are in the
70s at all sites as of 2 PM. As expected, dewpoints dropped quite
a bit resulting in RH values in the upper 20s to lower 30s. Mid
level trough over the area today will swing east tonight with the
mid level winds tending to shift to more northwest by Saturday
morning. Sfc high will then build in from the west tonight with
the clear skies continuing and winds becoming much lighter,
enabling temps to fall in the dry airmass. Lows were adjusted a
bit below NBM, but not as cool as MOS guidance.
&&
.SHORT TERM...
(Saturday through Sunday night)
Issued at 230 PM EDT Fri Apr 12 2024
This weekend will be clear skies as a surface high pressure system
settles in over the area. Saturday high temperatures will be in the
mid to upper 70s with night time temperatures in the 50s with
some patchy inland areas dipping into the upper 40s. Sunday, daytime
temperatures will reach the mid 80s inland with temperatures staying
slightly cooler along the coast. Night time temperatures will be
warmer than the previous night staying in the mid to upper 50s.
&&
.LONG TERM...
(Monday through next Friday)
Issued at 230 PM EDT Fri Apr 12 2024
High pressure conditions continue through the week parks off the
Atlantic coast for most of the week. Temperatures will be in the
mid to upper 80s reaching into the lower 90s at some inland
locations by Thursday. Low temperatures will get out of the 50s
and into the 60s mostly by Wednesday. We could see a weak frontal
boundary approach the area Thursday night based on the ECMWF, but
the GFS is much weaker with any boundary passing through so at
this time showing mainly high pressure ridge continuing with
silent POPs for the Thu-Fri time frame.
&&
.AVIATION...
(00Z TAFS)
Issued at 738 PM EDT Fri Apr 12 2024
Breezy conditions are expected to persist over the next several
hours, but subside through tonight and less than 10 knots by
midnight at all sites. Winds will shift towards the NW to N
tonight and into Saturday, with gusts up to around 20 knots
possible. Otherwise, VFR will prevail for the period.
&&
.MARINE...
Issued at 230 PM EDT Fri Apr 12 2024
Winds will surge out of the west and northwest this evening and
for the CWF we have exercise caution nearshore and small craft advisory
offshore for tonight period. Note that guidance used in the forecast
grids leaned toward the higher resolution winds from HRRR and
WRF. Winds will tend to relax Saturday late morning and afternoon
as high pressure builds in from the west. The high will dominate
over the area Sunday and then will translate east of the region
Mon thru Wed.
Rip Currents: Moderate risk of rip currents rest of today at all
area beaches with a dominate easterly swell at the coast. A moderate
risk is expected for NE FL beaches on Saturday with a low/moderate
risk for SE GA beaches on Saturday.
&&
.FIRE WEATHER...
Issued at 230 PM EDT Fri Apr 12 2024
The rest of today will be gusty with westerly winds of 15 to 20
mph leading to high dispersions area-wide. Most of SE GA as well
as some patchy areas along the FL/GA border will have high
dispersions for Saturday but weaker winds will allow dispersion to
be trend much lower into the 40s and 50s by Sunday. MinRH will be
near critical values inland area wide Saturday. NE FL will have
areas of patchy critical minRH values until about mid week. Winds
will begin to die down area wide Saturday evening as high pressure
settles into the area.
Main headlines continue to be the high dispersion today and patchy
high dispersion on Saturday. Winds are currently not high enough
for any small scale-type red flag warning area for Saturday.
&&
.HYDROLOGY...
Issued at 200 PM EDT Fri Apr 12 2024
Rainfall yesterday has produced pronounced river rises over area
rivers. Flood warnings for minor flooding are in effect along
portions of the Satilla, Santa Fe, and Suwannee Rivers and will
continue into next week. Additionally, Moderate flooding is still
forecast for Statenville along the Alapaha basin this weekend but
not as high as prior forecast. Moderate flooding forecast for
Santa Fe at Three Rivers Estates.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 49 77 52 83 / 0 0 0 0
SSI 53 76 55 77 / 0 0 0 0
JAX 51 77 52 82 / 0 0 0 0
SGJ 55 77 54 80 / 0 0 0 0
GNV 49 78 50 83 / 0 0 0 0
OCF 50 78 50 83 / 0 0 0 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...Small Craft Advisory until 10 AM EDT Saturday for AMZ470-472-474.
&&
$$
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
844 PM CDT Fri Apr 12 2024
.KEY MESSAGES...
- Following summer-like warmth, a lake enhanced front will bring
an abrupt temperature drop to northeast Illinois and
northwest Indiana Sunday afternoon-evening.
- Waves of showers and a good chance (30-40%+) for thunderstorms
Monday night through Tuesday night, some of which may be
severe, particularly Tuesday afternoon and evening.
- Warm and windy on Tuesday with southerly winds potentially
gusting to around 40-45 mph.
&&
.UPDATE...
Issued at 844 PM CDT Fri Apr 12 2024
Isolated showers continue to diminish in areal coverage and
intensity across northwest Indiana this evening, and will come
to an end shortly. Otherwise, clearing skies and diminishing
winds are the trends this evening, with quiet and milder weather
expected into Saturday.
Deep upper level trough/closed low was evident in vapor imagery
across the eastern Lakes and the Northeast this evening, with a
series of sheared mid-level vorts propagating southward within
the western periphery across the western Great Lakes. This
sheared vort axis has shifted east of the area since late this
afternoon, allowing subsidence and warming mid-level
temperatures and the loss of diurnal surface heating resulting
in the loss of instability across our eastern cwa. Showers and
earlier isolated thunderstorms have thus waned, and continue to
decrease in coverage and intensity as they shift southeast
across northwest and central Indiana. The few isolated showers
lingering currently over Newton/Jasper and eastern Benton
counties should move out within the hour, allowing clear skies
to prevail across the cwa tonight.
Strong northwest surface winds have also diminished markedly
since late afternoon, with the gradual weakening of both the
surface pressure and isallobaric gradients associated with the
deep low over southwest Quebec pulling away as well as the loss
of diurnal instability. Winds will continue to diminish
overnight and eventually back more westerly across our Illinois
counties toward morning as weak surface high pressure ridging
builds in from the west. Winds will shift southwest on Saturday,
allowing low level warm advection and abundant sunshine to warm
temperatures into the upper 60s and lower 70s by afternoon.
Winds may be just light enough to allow a slight southeasterly
lake breeze to develop along the immediate Illinois Lake
Michigan shore in the afternoon, which may keep locations right
along the lake just a little cooler.
Going forecast has all of the above in good shape, and other
than some minor adjustments to early evening pops and short-term
temp trends, no significant changes are needed.
Ratzer
&&
.DISCUSSION...
Issued at 335 PM CDT Fri Apr 12 2024
Through Saturday Night:
Widely scattered showers have developed across portions of the
area this afternoon, namely north of a Rockford to Joliet to
Fowler, IN line. These have managed to grow a bit taller than
anticipated which has resulted in greater coverage than
previously anticipated. In fact, some have managed to grow tall
enough to support electrification, with lightning strikes
observed in portions of Jasper County, as well as north of the
state line in southeast Wisconsin. As was the case yesterday,
there is a narrow convergence axis generally along/near the I-65
corridor that could support funnel cloud development yet again
though the better potential exists just to the southeast of the
forecast area where the RAP non-supercell tornado parameter
(NST) is up to 2. With any of the showers gusty winds up to 45
mph and pea sized hail/graupel will be possible along with a few
lightning strikes. Winds and shower coverage diminish with
sunset with clear skies overnight.
Saturday looks pleasant weather-wise with light west winds to
start the day and temperatures warming into the upper 60s to
lower 70s, warmest southwest. Winds will turn southwesterly
during the afternoon and gradually increase as warm air advects
into the region between the developing Northern Plains surface
low and high pressure across the Gulf Coast states. A low-
amplitude wave will traverse within the upper ridge which could
bring the potential for a few showers toward daybreak Sunday but
for now have kept the overnight hours dry.
Petr
Sunday through Friday:
A relatively mild start to the day on Sunday will ensure that most
of the area will be in the 70s come the late morning. Going into the
afternoon, some locations, particularly in the southwestern half of
our forecast area, should see temperatures climb to 80F for the
first time this year. At around the same, however, our northeastern
locales will likely start to see temperatures tumble as a lake-
enhanced front start to press inland, and eventually, between
nocturnal cooling and cold air advection behind the front,
temperatures should bottom out in the 40s overnight. There also
continues to be a fairly low (~15-20%) chance that a few showers
sprout along the frontal boundary in the afternoon (mainly in
northwest Indiana), but capping, dry air, and limited forcing
support aloft will likely be too much for any convergence-driven
attempts at convection along the boundary to overcome. However,
if these limiting factors are able to be overcome, the presence
of instability aloft associated with an EML over the region will
allow for any established convection to be capable of producing
lightning.
Mostly clear skies and modest warm air advection off of
southeasterly winds should allow for temperatures to recover back
into the 70s during the daytime on Monday across most of the area.
Locales near the Lake Michigan shore, particularly those in
Illinois, will be the main exception to this as an onshore flow
component to the winds will keep temperatures here several degrees
cooler than farther inland.
Monday night into Tuesday, a deep upper-level trough will eject out
of the southwestern CONUS towards the Upper Midwest, spurring a
fairly robust episode of lee cyclogenesis to our west in the
process, and bringing a much better chance for showers and storms to
our area. Showers and storms could be seen as early as Monday night
as warm air advection/isentropic ascent start to ramp up well in
advance of the developing low pressure system, but the main time
frame of interest to watch for potential severe weather in our area
will be Tuesday afternoon into Tuesday night as that is when we will
find ourselves in the system`s warm sector, which should be
characterized by surface temperatures in the 70s, dew points in the
upper 50s to mid 60s, and breezy southerly winds (with gusts
potentially approaching and exceeding 40 mph at times if rain and
cloud cover don`t end up being too much of a hindrance).
It`s still a little too early to dive into the specifics of this
potential severe weather threat as, still being four days out,
shifts and changes in forecast guidance are bound to happen and
alter the overall forecast expectations for any given event. In
fact, over the past several ensemble and deterministic model
runs, there has been a clear trend towards a slower and not-as-
deep low pressure system, which generally would be less favorable
for the overall chances and potential magnitude of the severe
weather threat in our area. That being said, even with a slower
and weaker surface low, the track of the surface low remaining
to our northwest should still draw at least a modest amount of
instability into northern Illinois and northwest Indiana which,
amidst seasonably strong deep-layer shear, would still present
the opportunity for storms to be severe as they track through the
area. The latest CIPS Analog guidance and CSU`s Machine Learning
probabilities corroborate this thinking, so the Storm Prediction
Center`s Day 5 15% contour that encompasses the entirety of our
forecast area continues to look appropriate at this time, but
we will continue to monitor forecast trends.
Showers and perhaps a few storms may linger around into Wednesday
before another system moves through the region during the latter
half of the week. This late week system could bring another round of
showers and storms to the area, though overall confidence in this is
low at this time. Much higher confidence exists in cooler
temperatures returning to the area going into the upcoming weekend.
Ogorek
&&
.AVIATION /00Z TAFS THROUGH 06Z SATURDAY/...
Issued at 627 PM CDT Fri Apr 12 2024
Forecast concerns include...
Scattered showers ending early this evening.
Gusty north/northwest winds early this evening.
Gusty southerly winds Saturday afternoon/evening.
Scattered showers will slowly dissipate through sunset as they
move southeast and away from the terminals. Isolated thunder is
also possible early this evening, but will remain southeast of
the terminals.
A lake boundary/wind shift moved through ORD/MDW shifting winds
to the north/northeast. Wind directions will slowly turn back
to the northwest over the next few hours. Gusts into the lower/
mid 20kt range are possible through sunset and then speeds/
gusts will steadily diminish after sunset. Winds will turn
west/northwest later this evening and remain west/northwest
through mid/late Saturday morning and then turn to the southwest
and eventually southerly by late Saturday afternoon when gusts
into the 20kt range will be possible. Gusts are likely to
continue Saturday night as strong low level winds develop which
may result in low level wind shear, for later Saturday night/
early Sunday morning. cms
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 10 PM CDT this evening for the IL
and IN nearshore waters.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Marquette MI
644 PM EDT Fri Apr 12 2024
.KEY MESSAGES...
- Deep low pressure over Quebec continues gusty north to
northwest winds up to 30-40 mph, stronger winds are expected
over the eastern UP.
- Periods of showers into next week, including Saturday night
and then through much of next week.
- Temperatures on most days will be above normal through the
first half of next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 352 PM EDT Fri Apr 12 2024
Current RAP analysis shows the strong low pressure system northeast
of Lake Huron over the Ontario/Quebec province line with weak sfc
high pressure along the Dakotas/Minnesota state lines. The mid level
trough is located just southwest of sfc low and is centered over
Lake Huron/southern Ontario. A broad mid level ridge is analyzed
over the Rockies/Plains with a closed low off the western U.S.
coast. With the sfc low and mid level trough no longer vertically
stacked well, the sfc low will weaken into tonight as it lifts north
through Quebec while the trough progresses east-northeast into
Quebec/New England. Lingering light rain showers over the far
eastern UP will diminish from west to east into this evening as the
sfc low departs. No major accumulations beyond 0.01" are expected.
This set up continues a tighter pressure gradient over the UP into
tonight resulting in some gusty northwest winds, especially over the
east. Gusts around 20 to 30 mph are expected over the western third
of the UP with the remainder of Upper Michigan gusting up to around
30 to 40 mph; some gusts along the eastern lakeshores could reach 45
mph yet this afternoon. Thus, the wind advisory will continue
through 8 PM EST this evening for Alger/Delta counties eastward.
While the northwest winds off Lake Superior have kept the eastern
lakeshores cooler in the low to mid 40s, temps elsewhere have warmed
up into the mid 40s to mid 50s with the warmest over the south
central UP; not much if any additional warming is expected today.
Tonight, sfc high pressure will gradually build in from the west and
the pressure gradient overhead will slacken. PWATs show a 0.1" drop
across the UP as drier air moves in from the northwest, something
already noted in the water vapor imagery over Minnesota. The drier
air will help clear skies out as northwest winds weaken; gusts drop
back down to around 20 to 30 mph by Saturday morning with strongest
winds located near the eastern lakeshores. Clearer skies will also
help bring lows down into the upper 20s to mid 30s, warmer near the
lakeshores.
&&
.LONG TERM /SATURDAY THROUGH FRIDAY/...
Issued at 412 PM EDT Fri Apr 12 2024
Saturday starts off dry and sunny with weak ridging over the area,
but a shortwave dropping into northern MN touches off waa/isentropic
ascent toward Upper MI by evening. This should bring an increase in
clouds ahead of a quick round of showers overnight. With an
advancing sharp 850mb theta-e gradient and vigorous upper diffluence
from the right entrance region of a 100kt upper jet streak extending
from northern Lake Superior into the Lower Great Lakes by the
evening, scattered showers should spread into w/nw Upper MI
generally after 00Z. That said, some of the simulated reflectivity
(though usually a little too aggressive with the onset timing) do
show some shower activity kicking off during the late afternoon in
the western UP. Scattered showers end by sunrise Sunday. A pool of
elevated instability of 100-400 j/kg builds toward Upper MI for Sat
night, and it may be just sufficient toward the MI/WI stateline for
a rumble or two of thunder. Following the showers on Sat night,
Sunday looks to be a nice mid-Apr day under increasing sunshine.
Highs Sat will be in lower 60s over the interior west half and
mostly in the lower to mid 50s elsewhere. Highs Sun will be well
into the 60s F across the interior w half and south central and
mostly in the mid to upper 50s elsewhere.
Will note a potential for dewpoints to drop both Saturday and Sunday
afternoon, with well-mixed and very dry model soundings. Increasing
clouds Saturday may inhibit this at least across the western UP. This
environment could see RH falling to as low as 20-25% across much of
the interior UP Saturday, while a somewhat more moist airmass Sunday
nevertheless may see RH falling into hte 30% range during the
afternoon. Fortunately, winds will be decreasing from west to east
Saturday morning, but some 15 to 20 mph gusts will be possible
during the afternoon Sunday.
Dry weather persists for much of Monday with the ridge still over
the Great Lakes. However, by late in the day the quasi-zonal flow in
the vicinity of the U.S./Canada border will be breaking down as a
shortwave drops out of the Gulf of Alaska into the NW U.S.
Downstream, the upper jet will be forced to lift northward, again
placing right entrance region upper diffluence over the area. There
are also hints of a weak shortwave tracking toward Upper MI. This,
in addition to some diurnal instability, could lead to a few showers
mainly over the western UP during the afternoon/evening.
Attention then turns to the wave over the Southwest U.S. that gets
kicked northeast by the shortwave dropping from Gulf of Alaska
through the NW U.S. Surface response will be a deep sfc low
organizing in the lee of the Colorado Rockies. This low will reach
peak strength over the Plains on Tuesday, and then weaken as it
lifts northeast into the Upper Great Lakes and northern
Ontario/Quebec Tue night into Wed. With a good surge of Gulf
moisture ahead of the approaching low (layer precipitable water
values increase to over an inch or 200-250pct of normal), expect
widespread showers, and maybe some thunder, to develop late Tue into
Wed. However, in spite of the high PWATs, ensemble probability
guidance is not very bullish on total rainfall from this system,
probably since the system and associated dynamics are weakening as
it moves across the area. Ensembles suggest a 60-80 pct probability
of a half inch or more of rainfall over south central portions with
less than 50 pct chance of a half inch across the rest of the fcst
area. Breezy conditions will develop as well Tue into Wed. Models
suggest showers may taper off a bit late Wed into Wed night behind
the low as it lifts to the northeast and a dry slot works in.
However, additional shortwaves ahead of and with the passage of the
approaching western CONUS trough and associated closed low could
reinvigorate showers late in the week. Otherwise, expect above
average temperatures to finally trend lower behind the midweek
system, falling below normal by Friday.
&&
.MARINE...
Deep low pressure is lifting NE of Georgian Bay this afternoon, with
NNW gales to 40-45 knots ongoing throughout eastern Lake Superior.
Winds will gradually decrease through the first half of the night as
the low pulls away and ridging builds into the Great Lakes. Winds
fall below gale force into Saturday morning, and below 20 knots into
the afternoon. Winds stay generally below 20 knots Sunday through
Monday. Another deep low will begin to organize on the lee side of
the Rockies late on Mon. Easterly winds will begin to increase late
Mon night to 25-30kt, highest over the western third of the lake.
Ensemble guidance indicates a 70 to near 100 pct chc of easterly
gales of 35-40kt Tue aftn into Tue night across much of Lake
Superior. The gales may linger into Wed morning before diminishing,
but winds stay elevated at around 20 to 30 knots through the rest of
the week.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 643 PM EDT Fri Apr 12 2024
VFR conditions will continue through the period. Winds will be gusty
overnight.
&&
.MARINE...
Issued at 412 PM EDT Fri Apr 12 2024
Saturday starts off dry and sunny with weak ridging over the area,
but a shortwave dropping into northern MN touches off waa/isentropic
ascent toward Upper MI by evening. This should bring an increase in
clouds ahead of a quick round of showers overnight. With an
advancing sharp 850mb theta-e gradient and vigorous upper diffluence
from the right entrance region of a 100kt upper jet streak extending
from northern Lake Superior into the Lower Great Lakes by the
evening, scattered showers should spread into w/nw Upper MI
generally after 00Z. That said, some of the simulated reflectivity
(though usually a little too aggressive with the onset timing) do
show some shower activity kicking off during the late afternoon in
the western UP. Scattered showers end by sunrise Sunday. A pool of
elevated instability of 100-400 j/kg builds toward Upper MI for Sat
night, and it may be just sufficient toward the MI/WI stateline for
a rumble or two of thunder. Following the showers on Sat night,
Sunday looks to be a nice mid-Apr day under increasing sunshine.
Highs Sat will be in lower 60s over the interior west half and
mostly in the lower to mid 50s elsewhere. Highs Sun will be well
into the 60s F across the interior w half and south central and
mostly in the mid to upper 50s elsewhere.
Will note a potential for dewpoints to drop both Saturday and Sunday
afternoon, with well-mixed and very dry model soundings. Increasing
clouds Saturday may inhibit this at least across the western UP. This
environment could see RH falling to as low as 20-25% across much of
the interior UP Saturday, while a somewhat more moist airmass Sunday
nevertheless may see RH falling into hte 30% range during the
afternoon. Fortunately, winds will be decreasing from west to east
Saturday morning, but some 15 to 20 mph gusts will be possible
during the afternoon Sunday.
Dry weather persists for much of Monday with the ridge still over
the Great Lakes. However, by late in the day the quasi-zonal flow in
the vicinity of the U.S./Canada border will be breaking down as a
shortwave drops out of the Gulf of Alaska into the NW U.S.
Downstream, the upper jet will be forced to lift northward, again
placing right entrance region upper diffluence over the area. There
are also hints of a weak shortwave tracking toward Upper MI. This,
in addition to some diurnal instability, could lead to a few showers
mainly over the western UP during the afternoon/evening.
Attention then turns to the wave over the Southwest U.S. that gets
kicked northeast by the shortwave dropping from Gulf of Alaska
through the NW U.S. Surface response will be a deep sfc low
organizing in the lee of the Colorado Rockies. This low will reach
peak strength over the Plains on Tuesday, and then weaken as it
lifts northeast into the Upper Great Lakes and northern
Ontario/Quebec Tue night into Wed. With a good surge of Gulf
moisture ahead of the approaching low (layer precipitable water
values increase to over an inch or 200-250pct of normal), expect
widespread showers, and maybe some thunder, to develop late Tue into
Wed. However, in spite of the high PWATs, ensemble probability
guidance is not very bullish on total rainfall from this system,
probably since the system and associated dynamics are weakening as
it moves across the area. Ensembles suggest a 60-80 pct probability
of a half inch or more of rainfall over south central portions with
less than 50 pct chance of a half inch across the rest of the fcst
area. Breezy conditions will develop as well Tue into Wed. Models
suggest showers may taper off a bit late Wed into Wed night behind
the low as it lifts to the northeast and a dry slot works in.
However, additional shortwaves ahead of and with the passage of the
approaching western CONUS trough and associated closed low could
reinvigorate showers late in the week. Otherwise, expect above
average temperatures to finally trend lower behind the midweek
system, falling below normal by Friday.
&&
.MARINE...
Deep low pressure is lifting NE of Georgian Bay this afternoon, with
NNW gales to 40-45 knots ongoing throughout eastern Lake Superior.
Winds will gradually decrease through the first half of the night as
the low pulls away and ridging builds into the Great Lakes. Winds
fall below gale force into Saturday morning, and below 20 knots into
the afternoon. Winds stay generally below 20 knots Sunday through
Monday. Another deep low will begin to organize on the lee side of
the Rockies late on Mon. Easterly winds will begin to increase late
Mon night to 25-30kt, highest over the western third of the lake.
Ensemble guidance indicates a 70 to near 100 pct chc of easterly
gales of 35-40kt Tue aftn into Tue night across much of Lake
Superior. The gales may linger into Wed morning before diminishing,
but winds stay elevated at around 20 to 30 knots through the rest of
the week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Wind Advisory until 8 PM EDT this evening for MIZ006-007-013-
014-085.
Lake Superior...
Small Craft Advisory until 8 AM EDT Saturday for LSZ244.
Gale Warning until 7 PM EDT this evening for LSZ245-248-265.
Small Craft Advisory until 8 AM EDT Saturday for LSZ245-248.
Small Craft Advisory until 11 PM EDT this evening for LSZ246-
247.
Gale Warning until 2 AM EDT Saturday for LSZ249-250-266.
Small Craft Advisory from 2 AM to 2 PM EDT Saturday for LSZ249-
250.
Gale Warning until 8 AM EDT Saturday for LSZ251-267.
Small Craft Advisory from 8 AM to 8 PM EDT Saturday for LSZ251.
Lake Michigan...
Gale Warning until 8 PM EDT this evening for LMZ221-250.
Small Craft Advisory until 2 AM EDT Saturday for LMZ221-250.
Gale Warning until 11 PM EDT this evening for LMZ248.
Small Craft Advisory from 11 PM this evening to 5 AM EDT
Saturday for LMZ248.
&&
$$
SHORT TERM...Jablonski
LONG TERM...LC
AVIATION...07
MARINE...LC
Area Forecast Discussion
National Weather Service Pocatello ID
237 PM MDT Fri Apr 12 2024
.KEY MESSAGES...
* Isolated thunderstorms will be possible Friday afternoon and
evening with a 5-14% chance of severe thunderstorms in and
around the CNTRL Mountains
* Seasonably warm temperatures will continue through the weekend
with highs in the 60s/70s each day
* Breezy winds are expected each day through early next week with
stronger winds favored on Monday as a cold front moves through
supporting a cooldown towards midweek
.SHORT TERM...Today through Saturday Night.
Early afternoon satellite imagery shows mostly sunny skies and
isolated showers across CNTRL/ERN Idaho as a H5 shortwave trough
lifts north out of the Great Basin. The storm environment this
afternoon and evening remains unchanged, still being conducive for
isolated thunderstorm development beginning between 3-6 PM and
continuing through around midnight tonight. The only changes have
been trimming down the areal coverage of thunderstorms to exclude
areas south and east of the Shoshone/Arco/Mud Lake Desert with
around a 10-40% chance probability of thunder on the HREF model
further NW into the CNTRL Mountains. We may see some isolated
storms outside this area but the focus will remain further north
and west.
The HREF model ensemble SBCAPE between 300-700 J/kg and around
25-35 ts of 0-6 km shear will support any organized cells or lines
to potentially develop into stronger storms with an emphasis on
these storms in the Magic Valley and CNTRL Mountains. The SPC has
expanded their marginal risk (5-14% chance of severe
thunderstorms) further east and now includes all of Custer County
and portions of Lincoln and Blaine Counties. The HRRR and NAM show
storms initially beginning in and around the Magic Valley before
lifting north into the Magic Valley with the HRRR showing
thunderstorm outflow gusts in excess of 40 mph and hail up to
around quarter size. Any convection will subside overnight with
dry conditions back for tomorrow outside of a slight chance for
isolated mountain showers.
Given it is currently 72 degrees early this afternoon at the
Pocatello Airport, today officially marks the warmest day in our
region so far this year with widespread 60s/70s across the area.
While staying below any record levels, this is the first time
Pocatello has gotten above 70 degrees since October 22nd 2023 or
173 days. Normal highs for this time of year are mostly in the 50s
making this stretch of mild weather about 10 to 15 degrees above
normal. As Friday`s H5 shortwave departs north into Montana for
Saturday, high pressure and southerly flow will remain in place
supporting highs in the 60s/70s with breezy winds out of the
south. MacKay
.LONG TERM...Sunday through next Friday.
The risk of showers and perhaps a t-storm will return Sun
afternoon as low pressure along the Pacific coast finally ejects
inland, but it`s posture still to the SW of our CWA will maintain
southerly flow and another decently mild day (highs in the upper
50s to upper 60s). A noticeable cooling trend finally kicks off
Mon and beyond as this initial low tracks east, and now-westerly
winds Mon afternoon may approach Wind Advisory criteria over the
ern Magic Valley and Raft River region. This is where everything
falls apart...we`ve been advertising a much cooler and wetter
pattern dominating the region for much of next week, but today`s
deterministic models look wildly different from yesterday`s runs
and offer a wide variety of different solutions. For example, the
GFS still favors another closed low dropping into Idaho from
Canada Tue, but the Canadian now keeps this system entirely up in
Canada, and this model and the ECMWF even show increasing
influence from at least "dirty" ridging now arriving as early as
Wed and Thu. Model agreement is non- existent regarding the
potential for additional low pressure features by the end of the
week as well. With the high degree of uncertainty, did not stray
from the NBM which has backed off on breezy conditions from Wed
onward and also isn`t advertising quite as much cooling (for
example, highs Wed in the 40s and 50s instead of 30s and 40s), but
still broadbrushes light PoPs across SE Idaho for much of the
week. WPC QPF remains VERY modest throughout the week (less than
0.50" even in the mntns). Even 500mb height cluster analysis
advertises about a 40% chance of increasing ridging Wed/Thu and a
60% chance of troughing remaining in place. In any case, the
sooner we can get the troughing out of here, the sooner we can
feel spring again. - KSmith
&&
.AVIATION...For the 18Z TAFS through 18Z Friday.
At least weak ascent from sfc heating, mid-level warm air
advection, and the overall approach of a weak, negatively-tilted
shortwave trough supports our continued expectation of at least
isolated showers and t-storms this afternoon and eve, especially
between 21z/3pm and 03z/9pm. The latest HREF suite of high-res,
hourly CAMs continues to favor the wrn corridor from SW Idaho NE
across portions of the Magic Valley into the Central Mntns with
best consensus for storms (maybe more sct coverage), thus we
maintain VCTS at KBYI and KSUN with slight tweaks to forecast
start/end timing. Further east, one or two models hint at some
potential for a shower or two, but with overall less coverage, we
cautiously have removed VCSH from the rest of our TAF terminals.
Dry-leaning low-levels will keep cloud bases pretty high, but IF a
t-storm were to make a direct hit on an airport, a very brief
period of MVFR cigs/vsbys can`t be ruled out, but with no
confidence in occurrence at this juncture. We`ll be closely
monitoring radar and satellite trends this afternoon. A couple
storm cells could produce small hail and gusty outflow winds in
excess of 50 MPH (and evidence of this is seen in the HREF wind
gust max as well as the last several HRRR runs). Model guidance
for wind is frankly very messy both this afternoon and most of
tonight, leading to pretty low confidence especially on direction
(and tossing a t-storm outflow or two into the mix could wreak
additional havoc). Broadly speaking, a SSW flow is expected to
dominate everywhere but KSUN (preceded by easterly winds at KBYI),
with some gusts as high as about 20kts away from any t-storms.
Skies may trend toward SKC again by late tonight and Sat, with
another breezy but drier day expected Sat afternoon. - KSmith
&&
.HYDROLOGY...
Water levels remain elevated on the Portneuf River in Pocatello
and Topaz where River Flood Warnings and an advisory,
respectively, remain in place. With warm temps continuing for a
few more days, expecting continued mid/high elevation snowmelt
which should lead to rises at both gauges over the days ahead.
Stay tuned for further updates over the days ahead.
McKaughan/MacKay
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$