Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/17/23
See below for an aviation forecast discussion for the 00Z TAFs.
&&
.SHORT TERM...(This Evening through Wednesday Night)
Issued at 243 PM CDT Tue May 16 2023
We continue to watch the progression of upper level smoke drifting
south-southwest into the CWA. RAP-Smoke Vertically Integrated output
has this handled pretty well when aligning it with current satellite
data. Trend remains in bringing this area of smoke further south and
west through the CWA into the evening hours, then an eastward drift
and eventually out of the area through the day Wednesday. Will then
have to keep an eye on the near-surface smoke potential Wednesday
night with the frontal passage, which the RAP model keeps bringing
across the CWA.
Aside from the smoke, the Wednesday night frontal passage is the
other forecast highlight. Timing remains similar to previous model
runs, with the front moving into north central SD after 21Z and
placement near MBG at 00Z. It appears the front will clear the whole
CWA by 12Z Thursday. Coverage of showers looks to be scattered to
perhaps numerous (in spots) along the front. Still not too excited
about the severe potential, but cannot rule out a few strong to
perhaps marginally severe storms with gusts over 50 mph across
central SD. Best instability with MLCAPE on the order of 1000-1500
J/KG sets up along/ahead of the front late Wednesday afternoon over
central SD, but quickly wanes with the loss of daytime heating, with
very limited instability further east across the CWA as the night
progresses. Shear values are lacking as well. So, seems there`s a
late afternoon/early evening threat for a few strong to perhaps
severe across central SD, but with the loss of daytime heating,
don`t expect that threat to translate too much farther to the east.
.LONG TERM...(Thursday through Tuesday)
Issued at 243 PM CDT Tue May 16 2023
Northwest flow shortwave moves across the area early in the extended
with a cold front moving rapidly out of the CWA. Showers will be
moving southeast associated with this feature...however with a
colder airmass, post frontal showers and weak thunderstorms are
possible according to BUFKIT profiles which is the reason for most of
the POPs here. Loss of daytime heating will reduce coverage of
showers/thundershowers and a 1024mb high sinks into the western
Dakotas Friday morning. Gradient winds east river should keep us
mixed, though 850mb fall as low as -2C in far northeast South
Dakota/western Minnesota, so even with mixing temperatures could
still fall well into the 30s. Mixing should keep any frost from
forming however...so it will take ground temps at/below freezing to
see any damage. Out in far northwestern counties, a bit better
scenario for radiative cooling thanks to the high placement, for
frost. Either way, its going to be close for some places. A general
warming trend follows thereafter.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 631 PM CDT Tue May 16 2023
Terminals KABR,KATY,KPIR,KMBG
VFR conditions are forecast through the TAF period. A layer of
smoke aloft will remain over the region tonight. It`s possible
some of this wildfire smoke may get ducted down to/near the ground
late in the day on Wednesday in the wake of a cold front forecast
to sweep southeast across the forecast area. For the moment, some
shower/VCTS has been introduced into the KMBG TAF way out at the
very end of the TAF valid period.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Dorn
SHORT TERM...TMT
LONG TERM...Connelly
AVIATION...Dorn
Area Forecast Discussion
National Weather Service La Crosse WI
617 PM CDT Tue May 16 2023
.DISCUSSION...(This evening through Tuesday)
Issued at 227 PM CDT Tue May 16 2023
Key Messages:
- Wildfire smoke to linger over the area into Wednesday.
- Next chance for rain comes in Thursday afternoon and lingers
into Friday. Limited CAPE and shear to work with with extremely
low severe probabilities.
Tonight - Wednesday...
Visible satellite shows an area of smoke from some Canadian
wildfires has worked south across the Upper Midwest and over the
local area. Looking at the vertical integrated smoke fields from
the RAP suggest this smoke might thin out a little overnight
before thickening up again during the day Wednesday. Some
potential that a little bit of the smoke could get mixed down to
the surface this evening behind the weak cold front that is
working across the area.
Thursday...
The next chance for rain is centered on Thursday afternoon and
night as a cold front sweeps across the region. The upper level
low over the central Canadian Rockies is expected to drop
southeast across the Upper Midwest and Great Lakes Thursday
afternoon into Friday. Still some differences between the models
on how far south the upper level low is expected to get before
turning more to the east to track across the Great Lakes. However,
all the models show that this system will have a positive tilt to
it placing the best pv advection and forcing on the poleward side
of the system. In addition, the flow south of the upper level low
looks to be zonal and not off the Gulf of Mexico, the moisture
return ahead of the low looks to be very limited. This is expected
to result in limited CAPE being available for the system to work
with. The NBM shows maybe around 500 J/kg of SB CAPE Thursday
afternoon with the NAM very similar with the ML CAPE. With the
positive tilt, the deep layer shear will be mainly behind the
front with maybe up to 30 knots in the 0-3 km layer available to
work with. This looks to be enough to support some general thunder
but not anticipating any severe storms to occur, which is in
agreement with current SPC day 3 outlook and Colorado State
machine learning forecast.
Friday into the weekend...
Depending on how fast the upper level low departs the region,
there is a small chance that some showers could linger into
Friday, mainly for parts of Wisconsin. After that, the upcoming
weekend looks to be dry with seasonable temperatures expected to
top out in the 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 630 PM CDT Tue May 16 2023
VFRs expected at both TAF sites (KRST & KLSE) for the 17.00-24Z
TAF period. Biggest concern is wildfire smoke, advecting south
through much of the period. High resolution models and cross
sections keep PM2.5 particles elevated 10k feet west of the
Rockies, and well above that locally. Smoke (FU) becomes more of a
forecast concern and question through Thursday as a subsequent
upper level trough may drive higher concentrations down the Upper
Mississippi River Valley.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...04
AVIATION...JAR
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
1017 PM CDT Tue May 16 2023
.UPDATE...
Issued at 1006 PM CDT Tue May 16 2023
Thunderstorms and showers continue to move across eastern Montana.
A cold front continues to move across Saskatchewan into eastern
Montana. Light and variable winds will continue across the state
as smoke continues to move across eastern North Dakota and could
settle due to the subsidence from surface high pressure. No
updates needed at this time.
UPDATE Issued at 633 PM CDT Tue May 16 2023
A cold front continues to approach the region from western Saskatchewan.
Satellite imagery shows some diurnal cumulus across eastern
Montana moving into western North Dakota, but with the loss of day
time heating clouds should diminish. Smoke from the wildfires in
Alberta continues to stream in from the North covering the Red
River Valley, some of the smoke has trickled into south central
North Dakota. Luckily there has been no visibility reductions from
smoke. Tonight surface high pressure could move some of the smoke
closer to the surface across eastern North Dakota ahead of the
frontal passage. Precipitation is still forecast ahead of the
cold front tomorrow. Adjusted the clouds grids match current
conditions.
&&
.SHORT TERM...(This Evening through Wednesday night)
Issued at 237 PM CDT Tue May 16 2023
For the remainder of this afternoon and evening, elevated smoke will
continue creating hazy skies across much of the state. The thickest
of this smoke looks to remain over the eastern half of the state.
Otherwise, expect dry conditions with highs reaching the upper 70s
to low 80s.
For the remainder of the period, upper low pressure will dig down
towards southern Canada. Associated broad surface low pressure and
cold frontal boundary will approach the state form the northwest
late tonight through the day Wednesday. As a result, there could
be a few showers in the north late tonight. As the frontal
boundary continues crossing the forecast area from northwest to
southeast, expect shower coverage to expand with a few
thunderstorms likely to develop during the day Wednesday. Post
frontal breezy northwest winds are also expected.
Moderate instability looks to accompany the fropa. However, the
RAP suggests somewhat limited shear with up to 30 kts of 0 to 6
km bulk shear. Although, this is a bit higher than was progged
earlier today. Model forecast soundings also suggest a skinny CAPE
profile, which is more supportive of pulsing thunderstorms than
longer lasting storms. At this point in time, the Marginal risk
remains just south of the border. However, wouldn`t be surprised
to see a few strong storms develop Wednesday afternoon,
potentially with a severe storm or two. These stronger to
potentially severe storms look most likely to impact the south
central part of the state.
One last note is that as the cold frontal boundary passes
through, the RAPSmoke model suggests smoke will be brought down to
the surface. This may result in visibility reductions to six
miles or less at times during the day Wednesday. However, these
reductions are likely to be relatively brief as smoke should
become elevated once again behind the front. Elevated smoke looks
likely to persist through the remainder of the period.
.LONG TERM...(Thursday through Tuesday)
Issued at 237 PM CDT Tue May 16 2023
Starting the extended period, a west CONUS ridge will be in place
with an upper low skating over far eastern North Dakota and
northern Minnesota. Shortwave energy off the low may produce a few
showers over the north and east during the day Thursday. As the
low moves out, the pattern will remain relatively stale through
most of the weekend as the west CONUS ridge remains in place and
northwestern flow aloft persists. The result being mostly dry
conditions with average temperatures Friday, as well as mostly
dry conditions and above average temperatures for the weekend.
At the surface, high pressure looks to slide down from Canada and
through the Dakotas Thursday night through Friday night. With the
high likely centered somewhere over western North Dakota Friday
morning, expect temperatures to tank. At this point in time, the
expectation is the temperatures will approach freezing, but
generally remain above freezing. That said, areas of frost are
possible over much of western ND Friday morning.
Highs Thursday are expected to be mostly in the upper 50s to
lower 60s. By this weekend and through the remainder of the
period, highs look mostly to be in the 70s to low 80s. Lows are
expected to drop into the 30s for most of the area Friday morning.
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1236 PM CDT Tue May 16 2023
VFR ceilings and visibility are generally expected through the
period, although skies may appear hazy at times from elevated
smoke. A cold frontal boundary passing through the state from
northwest to southeast tonight through Wednesday morning may
produce occasional showers and possibly a thunderstorm, along with
gusty northwest winds. Per usual, reduced ceilings and visibility
are possible with any shower or thunderstorm that passes through.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1236 PM CDT Tue May 16 2023
VFR ceilings and visibility are generally expected through the
period, although skies may appear hazy at times from elevated
smoke. A cold frontal boundary passing through the state from
northwest to southeast tonight through Wednesday morning may
produce occasional showers and possibly a thunderstorm, along with
gusty northwest winds. Per usual, reduced ceilings and visibility
are possible with any shower or thunderstorm that passes through.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Johnson
SHORT TERM...Telken
LONG TERM...Telken
AVIATION...Johnson
Area Forecast Discussion
National Weather Service Boston/Norton MA
935 PM EDT Tue May 16 2023
.SYNOPSIS...
A cold front will move across the region overnight, however very
little rainfall will accompany it. Wednesday will cooler, but
still dry and breezy. Sub-freezing temperatures are expected
Wednesday night. Clear skies and dry weather continues into the
rest of the workweek, with mild days and cooler nights. Expect
unsettled weather for the weekend, with near normal
temperatures.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
9:30 PM Update...
As anticipated, visibilities have begun to drop across the
immediate south coast, Cape, and Islands where dewpoint
depressions have dropped below 3F. Fog formation will peak over
the next couple of hours, but with the cold front already near
the MA/NH and MA/VT border, will dissipate quickly after 04-06Z
as winds shift to the north; drying out the column. Dewpoints
are rather high, at least compared to what they will be post
frontal, across SE MA, mainly in the upper 40s to mid 50s.
Surface temps are too warm away from the coast for any fog
formation, but did bring dewpoints in line with current
observations.
700 pm update...
The cold front is currently working its way through central VT
and NH. Latest hi-res model guidance has the showers currently
associated with the cold front drying up before reaching our
region. Winds this evening will briefly drop off after sunset
as the boundary layer decouples, but will pick up again as the
front passes through the region. Some fog is possible overnight
for the Cape and Islands due to the warm SW winds moving over
the cold waters. Confidence is low on fog formation, as models
tend to struggle with shallow moisutre scenarios and the
approaching cold front.
430 pm update...
Overall no big changes to the expectation for the weather
overnight. Looking at a cold front to push southward late this
evening and overnight. Moisture ahead of and with that front is
really lacking, with precipitable water values of about 3/4",
and very dry atmosphere below 8000ft or so. Hard to get a lot of
rain with that setup. Blended in the latest models, which
brought down the PoPs we had in place. Looking for at most a 25%
chance of precipitation across NE MA -- 10% or less elsewhere.
For most of us, the only clue to the frontal passage will be a
period of mid level clouds and a wind shift to the northwest.
Front should be pushing south of the region before dawn.
Guidance suggests the development of some low clouds and perhaps
some light fog across the waters south of Cape Cod with some low
level moisture pooling. Not totally confident in this aspect,
but did add it in to the forecast. Stuck with a blend for low
temperatures, so basically low 40s NW to near 50 SE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
430 pm update...
Colder air filters in behind the front, with 850mb temperatures
down to -2C to +2C by the afternoon. With plenty of sunshine and
dry air (precipitable water values 1/4"), we expect another day
of deep boundary layer mixing -- upwards of 7000-8000ft (roughly
750mb). So mixing that -2C to +2C air down to the surface
suggests maximum temperatures in the mid 50s to low 60s (with
the warmest across the south). The mixing will also bring down
the 20-25kt winds that will exist several thousand feet above
ground, so another day with gusty at times winds. Super dry, so
no PoPs. Even clouds will be limited, but we may see some
shallow cumulus develop at the top of that mixed layer. These
conditions also set the stage for another fire weather day. More
on that in the fire weather section. Per the RAP smoke model,
the smoke aloft from the Alberta wildfires we`ve seen recently
will actually push mostly south of the region, so perhaps a
return to deeper blue skies?
With clear skies and very dry air, and some continued weak cold
air advection, tomorrow night is expected to be rather cold,
especially for this time of the year. BUFKIT soundings show
10kts of wind continue all night just a few hundred feet above
the surface, so it won`t be a perfect setup for radiational
cooling. That said, it will be close enough. Normally cold spots
will be, well, cold. Sub-freezing temperatures are likely across
western MA, and more localized in the rest of the region. In
areas of eastern MA where we have more sandy soils, those
locations that typically radiate/cool off quick when in these
situations will probably do that again. I`m talking about you
Norwood, Taunton, Plymouth and even Martha`s Vineyard.
Statistical MOS guidance typically is better than raw model
outputs, so as prior shifts have done, I leaned on MOS as well.
Given the expected temperatures, have raised a Freeze Watch for
far western MA. Quite possible that spots outside of the watch
area will drop down to 30-32F as well. If that happens, it`s for
perhaps an hour, and that should not result in any real issues.
Plants around here are built for this. With the very dry air,
frost is actually probably going to be hard to find as well.
Maybe a spot here or there. Left it out of the forecast. Once
the sun starts to rise, temperatures will quickly rise as well,
so the cold threat is a small window.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
430 pm update...
* Continued dry weather Thursday/Friday
* Precipitation possible over the weekend
a 500 mb short wave ridge accompanied by a 1020mb surface high will
move over Southern New England on Thursday. With a weakening
pressure gradient due to the high pressure center moving overhead,
winds will be lighter then earlier this week. Fire weather may still
be a concern on thursday with the dry air mass over head, dew points
will still be in the low 20s and RH near or below 20%. between the
cold start Thursday morning and 850mb temps only between 0C-2C, high
temps on Thursday afternoon will be near normal in the upper 60s
except near the coasts where highs will struggle to hit 60F if a sea
breeze develops. Another cold night is expected Thursday night with
clear skies and calm winds. Used the lower end of guidance for lows
Thursday night due to the good radiational cooling expected. The
upper level pattern begins to change on Friday as an upper level
trough begins to eject out of the great lakes. The forcing from that
trough wont arrive until friday night or Saturday. Friday will
remain dry with increasing high level cloud cover. Winds will likely
be gusty out the south on Friday as the pressure gradient tightens
between the departing high and approaching low to the NW. The
southerly winds likely help boost highs into the low 70s.
Our next chance at measurable precipitation looks to start Saturday
morning. GFS and Euro models are starting to come in more agreement
with a surface low traveling up the coast and the main trough arriving
from the great lakes. Current ensembles give most the region a 60%
chance for one tenth of an inch of rain, but less then 30% chance
for a half an inch of rain. Dry air quickly works its way back in
behind the system for Saturday night into Sunday which should bring
an end to the rain showers. Decreasing clouds sunday will allow high
temps to warm into the mid to upper 70s.
An upper level ridge begins to build over the SE U.S Monday bringing
us back to clear and dry conditions with highs in the mid 70s.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
High confidence interior terminals Low confidence for Cape and
Island terminals
Tonight, main weather feature will be a cold frontal passage
between 03-10z (north to south). It`s a dry front, so main
features will be a band of mid- level clouds at 5000-10,000 ft.
Could be a very light shower (probably more like sprinkles),
especially across NE MA, but probability is so low that have
kept mention of any -SHRA out of the BOS TAF. Much of the
guidance suggests the development of some stratus and perhaps
some light fog across Marthas Vineyard and Nantucket after 04z,
so have included it for the ACK TAF. Confidence in this specific
aspect. Any IFR/MVFR conditions that do form will quickly come
to an end with the passage of the cold front (somewhere 07-10z
at ACK).
Tomorrow, another day with VFR. Surface N/NW winds should again
become gusty from the morning through mid-afternoon, with gusts
20-30kt.
KBOS Terminal... High confidence. Small probability (less than
25%) that BOS experiences a brief -SHRA with and just after
frontal passage (04-05z), but not high enough to include in the
TAF. Remaining gusty after frontal passage overnight.
KBDL Terminal...High confidence in TAF. Frontal passage will
shift winds NW overnight between 04-05Z. Winds will remain gusty
overnight after frontal passage.
Outlook /Thursday through Sunday/...
Friday: VFR. Breezy.
Friday Night: VFR. Breezy. Slight chance SHRA.
Saturday through Saturday Night: VFR. Breezy. Chance SHRA.
Sunday: VFR. Chance SHRA.
Sunday Night: VFR. Slight chance SHRA.
Monday: Breezy.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
430 pm update...
Overall High Confidence.
Pockets of fog are possible across the southern marine zones
for a brief period late this evening and early overnight before
winds switch to the NW/N behind a mainly dry cold frontal
passage. Marginal SCA conditions this evening into the overnight
hours will diminish. Post cold front conditions should still
remain below SCA thresholds, with winds gusting 18-23kt and
wave heights 2 to 4 feet, especially in the outer waters. At
this point have held off in issuing any small craft advisories.
Winds and seas diminish even more so late Wednesday and
Wednesday night.
Outlook /Thursday through Sunday/...
Friday: Low risk for Small Craft Advisory winds with gusts up
to 30 kt. Seas locally approaching 5 ft.
Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas locally approaching 5 ft. Slight chance
of rain showers.
Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers.
Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers.
Sunday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain
showers.
Sunday Night through Monday: Winds less than 25 kt. Areas of
seas approaching 5 ft. Slight chance of rain showers.
&&
.FIRE WEATHER...
430 pm update...
Maintaining the red flag warning for today that goes until about
sundown, and then expires. Not a lot of RH recovery overnight,
and tomorrow all the weather criteria are supportive of another
round of red flag criteria. Projecting lowest RH values down
around 20% and gusty winds pushing 25mph throughout the day. Of
course the fuel moistures aren`t improving between today and
tomorrow either. We have coordinated with fire partners and
WFOs ALY and OKX about tomorrow and the expectation is that we
will shift the watch for tomorrow up to a warning, but after we
get through today.
&&
.CLIMATE...
Record Low Temperatures Thursday, May 18th
BOS: 37F (2002)
PVD: 35F (1983)
BDL: 31F (1984)
ORH: 33F (2002)
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Red Flag Warning from 8 AM to 8 PM EDT Wednesday for
CTZ002>004.
MA...Red Flag Warning from 8 AM to 8 PM EDT Wednesday for
MAZ002>021-026.
Freeze Watch from late Wednesday night through Thursday
morning for MAZ002-003-008>010.
RI...Red Flag Warning from 8 AM to 8 PM EDT Wednesday for
RIZ001>007.
MARINE...Small Craft Advisory until 11 PM EDT this evening for
ANZ231>235-237.
Small Craft Advisory until 2 AM EDT Wednesday for ANZ250.
Small Craft Advisory until 8 AM EDT Wednesday for ANZ254>256.
&&
$$
SYNOPSIS...KP/Nash
NEAR TERM...Frank/KP/KS/Nash
SHORT TERM...Nash
LONG TERM...KP
AVIATION...Frank/KP/Nash
MARINE...KP/Nash
FIRE WEATHER...
CLIMATE...
Area Forecast Discussion...UPDATED
National Weather Service Cheyenne WY
559 PM MDT Tue May 16 2023
.UPDATE...
Issued at 545 PM MDT Tue May 16 2023
Updated 00z aviation discussion can be found below. Main forecast
remains on track this evening with isolated to scattered showers
and a few thunderstorms. Thunderstorms could briefly be strong to
severe with pea to nickel sized hail and upwards of 40 to 60 mph
winds, plus lightning. Did have a few reports of pea to penny
sized hail with the strongest of storms so far this afternoon.
Marginal parameters of only near 1000 J/KG MLCAPE and little to
now effective bulk shear will not be conducive for more then an
isolated risk of pulse strong to very briefly severe storms
through early evening. Risk will decrease post sunset as stability
increases with lingering showers occurring through mid to late
evening before all activity ceases by midnight. Another round of
afternoon showers and storms is expected tomorrow with another
marginal risk outlooked for the NE Panhandle per SPC.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 300 PM MDT Tue May 16 2023
The current short term weather analysis depicts a shortwave
disturbance slowly propagating southward over northwest Nebraska
as of 20Z, per GOES satellite WV imagery. Taking a look at the SPC
mesoanalysis for our sector, steep low-level lapse rates from
0-3km are 8-10 degrees C/km for our cwa as of 20Z, with a 50 knot
jet streak positioned over a similar area as well. Wind shear is
on the weak side, with less than 25 knots of effective bulk shear.
However, the moisture does look appreciable as dew points of the
upper 40s to middle 50s remain present for the Interstate 25
corridor into the Nebraska Panhandle. All that being said,
thundershowers have become present early this afternoon thanks in
part to the atmospheric setup localized to the Front Range and
Laramie Range toward portions of the Central Plains. This is co-
located with the SPC Day 1 Marginal severe Model guidance shows
this trend continuing through the early evening hours, with some
of the convection becoming potentially severe. The highest
likelihood of any single- cell thunderstorms transitioning to
potentially supercell thunderstorms are pinpointed to be in the
Nebraska Panhandle where moisture, lapse rates, and atmospheric
dynamics are the most favorable through sunset. Convection will
likely continue to initialize in southeast WY, but is likely to be
short- lived in duration. The main hazards will be isolated
strong wind gusts up to 60mph with the strongest convective
thunderstorms, and hail up to 1 inch in diameter. Isolated to
scattered rain showers will be present across the remainder of the
cwa. Model soundings depict inverted-V profiles between 21Z-3Z
today/this evening, thus gusty winds with even weak rain showers
could become present. Overnight, there will be weak winds across
portions of cwa, with moisture and the coolest nighttime
temperatures located across the North Platte River Valley from
Torrington to north of Sidney. Other low- lying valley areas in
the Nebraska Panhandle area will be favored for patchy fog. Hi-res
guidance from the HRRR and NamNest depict another area near
Chadron and Alliance seeing potentially patchy, dense fog from the
overnight hours through approximately 14Z. We will need to
monitor this in the event a Dense Fog headline may be prudent.
Wednesday will be more of the same as another opportunity for
widespread rain showers and thunderstorms become present by the
afternoon. The one difference maker will be that the atmospheric
forcing dynamics will become more organized due to an approaching
cold front. Lapse rates, surface moisture, and forcing will be
confined to the I-25 corridor towards the NE Panhandle after 18Z
Wednesday. SPC Day 2 has a Marginal Risk for severe thunderstorms
being possible in the NE Panhandle. Based off the latest model
data, this lines up nicely with what our thoughts are internally
regarding the potential for isolated strong winds up to 60+mph and
large hail. Highest confidence remains with the wind gusts due to
model soundings depicting inverted-V profiles, especially the NE
Panhandle. DCAPE values between 700-1000 J/kg, and MUCAPE between
500-1500 J/kg on model soundings east of I-25 should suffice more
organize convection. Niobrara and Sioux County have the strongest
signal for MUCAPE being above 1000 J/kg between 18Z-0Z Wednesday
afternoon. Thunderstorm activity should begin to wind down shortly
after sunset from west to east. Any organized convection is
anticipated to push toward the central Plains between 0Z-6Z
Thursday.
Much cooler temperatures are forecast for Thursday as the cold
front will have passed through the majority of our cwa, and
cloudy conditions persist for the region. Daytime highs will be on
the order of 10-15 degrees cooler, topping out in the 50s and 60s,
instead of the 70s to low 80s for the high plains. Showers and
isolated thundershowers will slowly push from north to south by
the late afternoon and evening hours. Cooler temperatures in the
higher terrain will remain present. Seasonal overnight lows can
be expected for most of the cwa, as the upper 30s to lower 40s
occur thanks to widespread clouds. A few snow flurries in the
highest elevations may remain overnight as cloud cover persists
coupled with the colder overnight lows.
.LONG TERM...(Friday through Tuesday)
Issued at 300 PM MDT Tue May 16 2023
The models are in pretty good agreement in showing the upper level
ridge building over the region through the weekend. This will
provide mild and dry conditions to the region. The coolest day will
be on Friday as Canadian high pressure builds into the area. This
should tend to suppress the majority of the convection southward
into Colorado on Friday, but one cannot rule out a few isolated
showers over the Snowy and Sierra Madre mountains on Friday.
Although, confidence is not high in this scenario. Saturday should
end up being a very nice day with afternoon highs climbing back into
the 70s with mostly sunny skies. The WPC clusters are showing some
signs of this upper level ridge beginning to flatten out on Sunday
in response to the upper level closed low moving into the Pacific
northwest. The ECMWF tends to keep this closed low mainly over the
Pacific northwest on Sunday through Tuesday while the GEM/GFS and
NAEFS Ensembles has this closed system a little further east over
the northern Rockies. Either way it looks like our Precipitable
Water values will be on the increase early next week as the
southerly flow advects more moisture into the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 545 PM MDT Tue May 16 2023
Main aviation concerns next 24 hours will be the ongoing isolated
to scattered TSRA/SHRA across SE WY, overnight lower ceilings/fog
in the North Platte River Valley near KBFF, and another round of
scattered TSRA/SHRA after 19-20Z Wednesday. TSRA/SHRA ongoing in
proximity to KCYS as of 00Z with additional activity north and
west. Carrying VCTS or VCSH for WY sites through 03-04Z with
activity ending thereafter. NE Panhandle sites currently more
clear of SHRA/TSRA but some isolated activity could occur near
KBFF through 03Z. Fog/low ceilings of IFR/LIFR could occur at KBFF
similar to this morning but signal is slightly less. HRRR hints
at very localized drops of visibility due to fog. Have trended
KBFF this direction from 09-14Z. Another round of TSRA/SHRA likely
Wednesday afternoon with VCTS/VCSH mentioned for all sites post
20Z. TSRA/SHRA could temporarily drop visibility down to 2-3SM
under stronger rain cores along with localized turbulence. Storm
tops Wednesday to near 350/400.
&&
.FIRE WEATHER...
Issued at 300 PM MDT Tue May 16 2023
Recent precipitation and the seasonal green-up has resulted in the
majority of fuels remaining below elevated to critical thresholds.
Minimum humidity values of 25 to 35 percent will be present this
afternoon and Wednesday afternoon. Isolated to scattered rain
showers have the potential to bring wetting rains greater than 0.10
inches this afternoon through Wednesday evening. Gusty and erratic
winds are possible with some of the thunderstorms during that
time.
&&
.HYDROLOGY...
Issued at 300 PM MDT Tue May 16 2023
The Little Snake River basin will continue to see water levels rise
through the week in response to warming temperatures and copious
snow melt taking place. This will also cause rises on the North
Platte River basin especially near Encampments and Saratoga.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...JSA
SHORT TERM...BW
LONG TERM...REC
AVIATION...JSA
FIRE WEATHER...BW
HYDROLOGY...REC
Area Forecast Discussion
National Weather Service Duluth MN
858 PM CDT Tue May 16 2023
.DISCUSSION...(This evening through Monday)
Issued at 351 PM CDT Tue May 16 2023
Summary: Wildfire smoke from Canada and near-critical fire weather
conditions remain the primary forecast concern today into
tomorrow. Frost will also be possible along parts of the WI South
Shore tonight as temps drop to around 34 degrees. A cold front
entering the region tomorrow night into Thursday will bring
widespread showers with embedded thunderstorms. Following the
front, scattered showers will be possible on Friday before high
pressure brings sunny skies on Saturday. With the exception of
Friday, temps will remain warm across the vast majority of the
CWA.
The primary near-term forecast concerns are near-critical fire
weather conditions and wildfire smoke from Canada entering the CWA.
A dry cold front propagating through the CWA this afternoon has
resulted in decreased smoke aloft, reflected in satellite obs this
afternoon. The HRRR smoke model continues to handle this event
poorly, showing no vertically integrated smoke over the CWA.
Fortunately, both the RAP and Canadian smoke models continue to
perform well with this event. The near surface smoke model from the
RAP shows minimal sfc smoke tomorrow, which should limit air quality
concerns. However, the CWA is expected to see another day of hazy
skies as the RAP shows a high concentration of vertically integrated
smoke aloft. Capped sky cover at 50 percent CWA-wide for tomorrow,
since sunlight is likely to filter through smoke aloft, similar to
today.
Conditions for the day tomorrow will be following the trend of the
past few days, with dry conditions and warm temps. Preceding the
warm temps will be low temps that may produce frost along portions
of the South Shore in WI. Issued a Frost Advisory this afternoon
for Douglas, Bayfield, and Ashland counties due to the potential
for temps as low as 34 degrees tonight. Minimum relative humidity
dropping to or below 25 percent across the Arrowhead and in the
pine barrens of Douglas and Bayfield Counties will very likely
lead to near- critical fire weather conditions. South winds of 10
to 15 MPH and gusts to around 20 MPH in the MN Arrowhead also
increase fire weather concerns for tomorrow. A change in the dry
pattern comes Wednesday night into Thursday as a trough that is
currently traversing a large ridge to our west arrives into the
region.
This trough will result in a low pressure center moving through
Manitoba and Ontario tomorrow night through Thursday. An attendant
cold front will be sweeping through the CWA over the same time
period, with widespread rain expected through the day Thursday. A
few embedded thunderstorms may be possible as the cold fropa occurs
on Thursday given favorable 0-6km bulk shear of 30-40 knots.
However, the thermodynamic environment will be marginal at best on
Thursday. Model soundings show weak lapse rates and model MUCAPE is
only up to a few hundred J/kg in the CWA. Therefore, severe weather
is not anticipated on Thursday as this front moves through.
Following the cold front on Thursday, cyclonic flow combined with
cool air aloft will likely lead to scattered diurnal showers on
Friday. High pressure will be regaining control of the pattern on
Saturday, leading to a pleasant day with sunny skies and warm temps
in the 70s. Several global ensemble members for QPF show that
showers may be possible Saturday night into Sunday along a cold
front for portions of the CWA.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 620 PM CDT Tue May 16 2023
VFR conditions are expected through this TAF period. Easterly
winds this evening shift southeasterly by early Wednesday morning
and then southerly into the midday hours tomorrow. Lofted smoke
could return again Wednesday and is represented by the SCT100 in
place at some terminals. If smoke makes it to the ground, then
future issuances may need a limited vis restriction.
&&
.MARINE...
Issued at 855 PM CDT Tue May 16 2023
Winds and waves will subside tonight as the pressure gradient
relaxes. Another northeast winds of 10 to 20 knots and gusts of
15 to 25 knots are possible Wednesday afternoon, mainly at the
head of the lake. These conditions may prompt Small Craft
Advisories to be needed from Silver Bay to Duluth for tomorrow
afternoon. A stronger cold front will move eastward across the
region on Thursday, bringing a period of stronger winds, light
rain, and possibly a few thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 37 62 46 66 / 0 0 20 90
INL 43 75 50 62 / 0 10 50 70
BRD 45 76 56 68 / 0 0 30 80
HYR 36 70 50 73 / 0 0 10 80
ASX 33 64 48 70 / 0 0 10 80
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Frost Advisory from 2 AM to 7 AM CDT Wednesday for WIZ001>003.
MN...None.
LS...None.
&&
$$
DISCUSSION...Unruh
AVIATION...NLY
MARINE...NLY
Area Forecast Discussion
National Weather Service Quad Cities IA IL
656 PM CDT Tue May 16 2023
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 216 PM CDT Tue May 16 2023
A mix of sun and clouds was seen over all of eastern Iowa,
northwest Illinois and far northeast Missouri early this
afternoon. Surface analysis showed an area of high pressure
centered over central Nebraska and Kansas, with ridging extending
over the Midwest. Meanwhile, a backdoor cold front was in place
from north central Minnesota eastward across the Great Lakes into
northern Ontario.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 216 PM CDT Tue May 16 2023
[Key Messages]
1) Backdoor cold front arrives tonight with winds shifting to the
east
2) Smoke from Canadian wildfires arrives tonight and persists
through tomorrow
[Discussion]
The primary weather concern in the short term period is the arrival
of the aforementioned backdoor cold front from the north tonight. Not
expecting any precipitation with its passage as lift and moisture
levels with the front are weak. Weak CAA accompanying the front,
with winds gusting around 20 MPH at times tonight, will help lower
temperatures into the low to mid 40s mainly for areas in northwest
Illinois and far northeast Iowa. Elsewhere, temperatures in the 50s
are expected. For tomorrow, with east winds persisting, highs are
expected to range from the upper 60s (northwest Illinois) to near 80
(northeast Missouri).
The next concern will be the arrival of smoke from Canadian
wildfires, which looks to build into the area with the arrival of
the cold front tonight. The RAP remains the model of choice with
this package given its larger domain, with the HRRR continuing to
struggle with overall coverage and timing. Vertically integrated
smoke calculations show the bulk of higher smoke concentrations
arriving across the area Wednesday afternoon, persisting into the
early portions of the long term period. Thankfully, much of this
will remain aloft with little to mix it down to the surface. The
only exception may be with the frontal passage tonight, as vertical
mixing temporarily increases along it. Otherwise, expect a milky
haze appearance with the sky and a nice sunset!
.LONG TERM...(Wednesday night through Tuesday)
Issued at 216 PM CDT Tue May 16 2023
[Key Messages]
1) Wildfire smoke persists through Thursday
2) Chance of showers/storms Thursday night through Friday
3) Dry and warm through the weekend
[Discussion]
Wednesday night and Thursday...
Dry weather is expected for this period with clouds on the increase
ahead of our next weather maker approaching from the west. Wildfire
smoke will also be in place aloft, but will start to get shunted
east with the arrival of stronger winds aloft. Increasing southerly
flow and WAA will help afternoon highs climb into the upper 70s to
mid 80s.
Thursday night and Friday...
Positively tilted shortwave and surface front will move into the
area to start the period, with enough lift and moisture in place to
lead to an increasing threat of showers and storms. Bulk of
precipitation will fall during the overnight hours, but some
guidance tries to hold on to POPs through much of Friday morning
into midday (GFS). Will be holding on to the NBM which favors
precipitation chances mainly from the 00z-12z period Friday. With
little in the way of vertical shear, low instability, conditional
lapse rates aloft and timing of the front arrival during the
night, the overall severe weather risk is low at this time.
Friday night on...
Dry weather will be the rule for this period as strong high pressure
builds across the Midwest and Great Lakes. Expect temperatures near
normal for the weekend, with a trend back above normal next week
once surface flow shifts back to the south.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 656 PM CDT Tue May 16 2023
VFR conditions are expected through the period with no sig wx
impacts to aviation expected.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Speck
SHORT TERM...Speck
LONG TERM...Speck
AVIATION...Gibbs
Area Forecast Discussion
National Weather Service Glasgow MT
200 PM MDT Tue May 16 2023
.DISCUSSION...
Going forecast was in good shape but humidity has been a bit
higher than anticipated and has begun to generate cumulus (eastern
zones) and isolated thunderstorms over central Montana. HRRR and
SREF models suggesting a bump up in pops through tonight as a
result but with little shear, storms will not be severe. Gusty
winds are possible if they collapse however, so added that
wording.
Otherwise, issued a Lake Wind Advisory for Wednesday afternoon as
a wind gust to 30 mph has about a 50-70% chance. TFJ
MORNING DISCUSSION:
Synoptic Setup: Hot high pressure from the desert southwest has
worked its way up into a ridge that runs north into the Pacific
Northwest and British Columbia. To the northeast a large trough
has positioned itself over the eastern half of the Hudson with
roughly northwest flow residing between these two large features
from Yukon through Alberta and into northeast Montana. Within this
flow are several meso to sub-synoptic ridges and troughs which
will lead to a bit of an unsettled pattern.
Today: A sub synoptic ridge will will move through the
territory keeping conditions warm with highs int he 80s and
clear skies.
Tonight through Wednesday: As the ridge exits early in the
evening a meso trough will smash a cold front into the area behind
it before midnight, flipping light winds to gusty ones out of the
northwest. Hit-and-miss showers and thunderstorms are expected to
accompany the frontal passage with them developing over the
central Montana mountains in the afternoon and getting pulled
along the front once it arrives. Shear profiles suggest that this
will be just general thunder with no severe elements. With the
hit-&-miss nature and high bases evaporating rain before it hits
ground most locations will see very little if any QPF with a few
hundredths being the higher totals.
Wednesday night into Friday: Cooler stable high pressure will
settle into the region at the surface generating light winds,
clear to partly cloudy skies and highs in the 60s and 70s.
Friday night into Sunday: Ridge to the west will become thin yet gain
more prominence over eastern Montana. Being thin, there are
higher chances for meso-scale disturbance with extra moisture
breaking through and generate isolated showers and thunderstorms,
but the prominence means that temps will start to rise back into
the 80s for highs.
Monday onward: Ensembles begin to break down and go out of phase
with the destruction of the ridge across the region. A few runs
are suggesting a southwest flow pattern with maybe some severe
weather, but disagreements in the members are too heavy to bring
any confidence to that possible forecast. GAH
&&
.AVIATION...
UPDATED: 2200Z
FLIGHT CAT RANGE: VFR
DISCUSSION: A cold front moving through the area this evening will
bring a wind shift along with scattered convective rain showers
and a few THUNDERSTORMS. Chance for showers at any given terminal
is only about 40%, so will be using Prob30s to handle it for now.
This shower activity will begin impacting KGGW around 03Z and
transitioning from northwest to southeast across the rest of the
terminals overnight. Nocturnal showers will be mostly high based
around 8 to 10 kft and should clear the area by about 15Z
Wednesday morning.
WIND: Light (less than 10 kts) southwest and west early evening,
then becoming northwest behind a cold front late this evening and
accelerating to 15 to 25 kts Wednesday morning.
GAH/TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory from noon to 7 PM MDT Wednesday For Fort Peck
Lake for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.
&&
$$
weather.gov/glasgow
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
611 PM CDT Tue May 16 2023
...AVIATION UPDATE...
.DISCUSSION...(This evening through Tuesday)
Issued at 325 PM CDT Tue May 16 2023
Key Messages:
*Warmer tomorrow with a chance for thunderstorms late tomorrow
evening.
*Cold front Thursday with continued thunderstorm chances.
*Dry and mild Friday and Saturday and then warming through early
next week.
The stratus deck has continued to erode to the southeast today and
only a little scattered cumulus remains on satellite this afternoon
across southeastern portions of the area. Winds are light with high
pressure at the sfc and we are still on track to top out in the 70s
today, quite a bit warmer than yesterday. Clear skies will continue
tonight with light and variable winds and lows in the 40s to near
50. There could be the potential for a little bit of fog to form
towards dawn but models don`t seem too keen on this potential, so
have not included it in the forecast at this time.
Warmer still on Wednesday with highs in the 80s and continued light
winds that will shift to being out of the south which will help us
to warm. Some thunderstorms are expected to develop with a sfc trof
moving east later in the evening hours but should weaken some as
they move towards the area. Have delayed the onset of PoPs as models
have slowed down the progression and the onset of precipitation for
the western portions of the area.
A cold front comes through on Thursday and reinvigorates
thunderstorm chances during the day and particularly the afternoon
hours. Some of these storms could be on the strong side, with around
500-1,000 J/kg of MUCAPE but severe storms are unlikely as bulk
shear is rather weak and limited. There is also the potential for
northern most portions of the area to be affected by a little near
surface smoke Thursday late morning and into the afternoon according
to the RAP Smoke model, from the wild fires up in Canada. This might
bear some watching in the coming days, even with the potential for
thunderstorms in the area (which might negate the smoke).
Cooler temps on Friday as a drier pattern sets in for the weekend
and into early next week. Highs will be in the 60s and 70s with
breezy winds Friday afternoon. Ridging aloft will build over the
Western CONUS and will help keep us dry and warming into the weekend
and early next week. Highs on Saturday will be in the 70s, and back
into the 80s on Sunday and Monday. There is a small chance for a few
isolated storms to pop up across the far southwestern portions of
the area Sunday afternoon, but a vast majority of the area will
likely remain dry.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 607 PM CDT Tue May 16 2023
VFR conditions are expected through the TAF period. A few cirrus
clouds may be present this evening, but skies should be clear the
remainder of the period.
Winds will be light and variable (6 kts or less) through Wednesday
morning. Winds will become southerly at around 7 or 8 kts
Wednesday afternoon into Wednesday evening.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Shawkey
AVIATION...Hickford
Area Forecast Discussion
National Weather Service Grand Junction CO
605 PM MDT Tue May 16 2023
.SHORT TERM...(Tonight through Wednesday night)
Issued at 300 PM MDT Tue May 16 2023
Showers and storms began to fire between 11 am and noon as
expected across the higher terrain. The HRRR seemed to verify
pretty well with convective initiation with the northern areas
seeing the best activity and coverage. However, storm coverage is
much less than the previous couple days and storms are struggling
to survive as they drift off the terrain, appearing pulse like and
producing some outflow winds as outflow boundaries are evident on
radar through the lower elevations. It makes sense that the
eastern Uintas into northwest Colorado is the hot bed for the
better activity as the upper level jet support remains to the
north over Wyoming, so they are in closer proximity to this
added source of lift. Our CWA remains under this westerly flow as
a ridge of high pressure is overhead and allowing this moisture to
be trapped underneath and recycled. Precipitable water values will
remain in the 0.5 to 0.6 inch range on average today and tomorrow
as the pattern largely remains unchanged. The main threat with
storms today is gusty outflow winds and lightning. We could see
some brief locally heavy rain and small hail with a few of the
stronger storms but this appears short-lived and isolated at best.
For Wednesday, the jet remains along the northern Colorado and
Wyoming border, with zonal flow continuing under high pressure.
Storms will favor the high terrain, developing in the afternoon like
today, with storms having a tough time surviving into the lower
elevations. Changes in the pattern and coverage appear Thursday
and beyond...more on that in the Long Term section. But for the
time being, today and Wednesday will be less coverage and activity
than later in the week. Temperatures as a result will be warmer
with highs 5 to 10 degrees above normal with partly to mostly
sunny skies in the valleys and building cumulus and storm activity
favoring the high terrain in the afternoons. Storm activity
should end around sunset both days with the loss of daytime
heating and limited forcing to help sustain activity.
.LONG TERM...(Thursday through Tuesday)
Issued at 300 PM MDT Tue May 16 2023
In general, Rex-Blocking pattern persists for much of the long term
period along the Western US, maintaining fairly consistent weather
for the region: unsettled and warm. Thursday brings an uptick in
storm coverage, as well as intensity, as a short wave rotates around
the base of closed low displaced to the northeast. The trailing end
of its trough axis carries along a weak upper level jet and swath of
positive vorticity as the whole system swings across the Central
Rockies. Jet dynamics and PVA will aid as a lifting mechanism,
though, orographics typically suffice in this department. Other key
components include, moisture and instability. In terms of available
moisture, PWAT levels will continue to range from 150 to 200 percent
of normal, which translates to precipitable water values of 0.5 to
0.6 inches across the board. NamNest data trickling in support
elevated SBCAPE by Thursday afternoon, as well, which would support
the longevity of thunderstorms...rather than cells dissipating as
soon as they drift on higher terrain. Main concerns with storms on
Thursday include periods of heavy rain, small hail, lightning and
gusty outflow winds. Basins still filled with a heavy snowpack are
expected to see an acceleration of snowmelt due to rain on snow, IF
cells materialize. Still some uncertainty there, with regard to
where and how much rain falls. However, there is potential for
rivers rising due to increased runoff from warm, spring
temperatures as well.
The blocking pattern shifts east on Friday into the weekend, which
will shunt moisture content to the southern half of the CWA. Storm
development will favor the moist side of the zonal line, therefore,
expect higher coverage for afternoon convection south of the I-70
corridor. The next low pressure system that`s projected to nose into
the PacNW will likely break down the Rex-Block. However uncertainty
grows with the variance between deterministic guidance beyond
Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 543 PM MDT Tue May 16 2023
Showers and storms will continue to dissipate this evening but not
before throwing out some gusty outflow winds. This could impact
TAF sites mainly along and north of I-70 over the next few hours.
Otherwise VFR conditions will persist over the next 24 hours.
&&
.HYDROLOGY...
Issued at 300 PM MDT Tue May 16 2023
Forecast hydrographs continue to show elevated river and stream
flows/stage through Friday. Areas across the north, namely the Yampa
River Basin, are exceeding Flood Stage and even Moderate Flooding in
some areas. River flood products will continue, at least, into the
weekend to cover forecast peaks within the next 10 days. River
levels and flooding potential will depend on temperatures and
precipitation during this period, so there remains some uncertainty
in the river forecasts in that regard. Increased cloud coverage
could suppress temperatures and thus reduce snowmelt/runoff. In
contrast, heavy rainfall over a specific basin would increase
snowmelt and runoff...
Despite uncertainty, if located in the warning or advisory areas,
please stay vigilant to changes in the river, as conditions and
hazards may change minute by minute. Water is already running with
high levels and fast currents along most main stems, including the
Yampa, Colorado, Green, Gunnison and Dolores Rivers.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...MDA
LONG TERM...ERW
AVIATION...TGJT
HYDROLOGY...ERW
Area Forecast Discussion
National Weather Service Green Bay WI
939 PM CDT Tue May 16 2023
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 219 PM CDT Tue May 16 2023
A cold front will continue making its way through central and
east-central Wisconsin this afternoon, turning winds to a north to
northeasterly direction. Satellite imagery shows a layer of smoke
in the atmosphere above 12,000 feet from the wildfires in Canada.
The cold front is expected to push through the rest of the region
dry given the dry atmosphere and likely some influence from the
smoke above the surface filtering out some of the incoming solar
radiation.
Skies are expected to clear overnight with subsidence behind the
cold front as the RAP Vertically Integrated Smoke product
indicates the smoke will push south with the cold front. Overnight
lows are expected to tumble into the 30s with some patchy frost
possible in central and north-central Wisconsin. Given the brief
period of cold temperatures tonight will not issue any
frost/freeze headlines for tonight.
A surface high will build in from the northeast Wednesday morning,
then push off to the east during the afternoon. Although skies
will start out mostly sunny, the RAP Vertically Integrated Smoke
product indicated the smoke from the west will advect back into
the region Wednesday morning and linger across the area through at
least the afternoon hours. Therefore, some filtered sunshine is
once again expected on Wednesday from the wildfires. The
combination of filtered sunshine and southeasterly winds will keep
temperatures cooler than today. Highs on Wednesday are expected to
only rise into the 60s with the warmest temperatures across
north-central and central Wisconsin away from the Great Lakes.
Further east temperatures near the lake will be limited to the
50s.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 219 PM CDT Tue May 16 2023
Through most of the long term forecast the pattern features broad
ridging over the west coast leading to northwest flow across
central and northeast Wisconsin. This will result in a couple
mid- level shortwaves/sfc fronts impacting the area and
temperatures generally near to slightly below normal.
The forecast starts out dry Wednesday night, and then the first
shortwave/sfc cold front will move through Thursday or Thursday
night. Starting out with a very dry airmass in place, so expect it
will take a while for saturation to occur and rain to begin, and
models seem to be latching onto the later start time. Therefore,
this will bring about some elevated fire weather potential on
Thursday afternoon ahead of the cold front. Forecasting minimum
RHs approaching 25 to 30 percent in far northern Wisconsin, high
temps in the 70s, and south winds gusting up to 30 mph. The later
arrival will also mean less instability to work with, but there is
still some, so kept a chance of thunderstorms as well. Severe
weather in not likely, with max CAPE values of 300 to 700 J/kg.
After the front moves through, cooler temps will settle in with
highs on Friday only in the middle 50s to middle 60s. Models still
vary on how quickly the shortwave departs, with the ECMWF and
Canadian keeping it around through Saturday morning. Similar to
the previous forecast, kept chance PoPs through Friday night and
then dry for the rest of Saturday as high pressure builds in.
Another weak shortwave and coinciding sfc front moving through on
Sunday, but time sections show a very dry atmosphere, so not
expecting much, if any, precip.
West coast ridging starts to migrate east and flatten late this
weekend and early next week. This will result in a change to
southerly low-level flow and somewhat warmer temperatures early
next week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 938 PM CDT Tue May 16 2023
VFR conditions are expected through at least Wednesday night. An
elevated smoke layer from forest fires in northern Canada may
return to the area Wednesday, but should not affect surface
weather conditions.
&&
.FIRE WEATHER...
Issued at 219 PM CDT Tue May 16 2023
Low humidities between 15 and 25 percent are expected on
Wednesday afternoon across north-central and far northeast WI,
though high temperatures will be cooler into the low and middle
60s and winds will remain light in the 5 to 10 mph range. This
will bring elevated fire weather conditions across this area
during the day on Wednesday.
Elevated fire weather conditions are also possible on Thursday as
temperatures will be warmer in the low to middle 70s with gusty
winds. However, RH values will be higher in the 25 to 30 range
due to rain potential in the afternoon.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM.....Kurimski
LONG TERM......KLJ
AVIATION.......RDM
FIRE WEATHER...Kurimski
Area Forecast Discussion
National Weather Service Grand Rapids MI
730 PM EDT Tue May 16 2023
LATEST UPDATE...
Aviation
.DISCUSSION...(This evening through next Tuesday)
Issued at 207 PM EDT Tue May 16 2023
- Dry cold frontal passage through late afternoon
The cold front up around Cadillac was dropping steadily southward.
Most of the clouds with this front were up around 10k ft.
Conditions below were dry. This front is not forecasted to pick up
any additional moisture. Thus as the front drops southward through
the CWA, no precipitation is forecast. This is how we currently
have the forecast and no changes are anticipated.
- Some Frost Possible Up North Tonight
The atmosphere behind this cold front will be cooler and continued
dry. Skies will remain mostly clear. The wind however is forecast
to remain up through the night. Ensemble wind gust forecast from
Big Rapids shows mean gust values of 10 to 15 knots through the
night. The main reason for the winds tonight is because the
surface high pressure system will be building in and we remain in
the pressure gradient. Generally this limits the frost potential.
Thus we are leaning away from a Frost/Freeze headline at this
time.
- An increased potential for Frost/Freeze headlines Wednesday
night
The pressure gradient weakens in the afternoon...which sets the
stage for the winds to go light early in the evening. It will be a
dry air mass in place...so good radiational cooling looks likely.
High temperatures will also be lower Wednesday as compared to
today`s we will get off to an early start for unseasonably cool
overnight low`s. Ensemble min temperature values look colder than
tonight`s values, especially for inland locations like Lansing and
Mount Pleasant. We will feature temperatures dropping into the
30`s for inland locations.
- Potential for some showers Friday into Friday night
The most recent run of the models generally show a closed mid
level low in central/northern WI 18z Friday, heading east. The
main lift and moisture depth here in MI is progged to come through
Friday. Mid level lapse rates do steepen up but not enough to
warrant a risk for thunder throughout the CWA. Ensemble mean
values are mostly a third of an inch or less with some spread.
Bufkit overviews from the NAM show a 6 to 8 hr period of deeper
moisture and lift for KGRR Friday morning with the GFS fairly
similar. This is when we will feature the highest POPs.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 730 PM EDT Tue May 16 2023
We currently have a frontal system dropping down through the
terminals this evening. The only thing this front has is a wind
shift from WNW to N and some mid clouds with it. In addition, a
band of smoke from the Canadian Wildfires is progressing through
the area to the south. The mid clouds will clear out toward or
just after midnight for the southern terminals, and winds at all
locations will become from the NE.
Skies will be mostly clear on Wed, but we are expecting more smoke
to move in around 25k ft agl. We have left a bkn250 layer in the
forecast for Wed to account for this. Winds will remain from the
NE at most of the sites. KMKG will see their wind become from the
NW as the lake breeze kicks in around 18z.
&&
.MARINE...
Issued at 207 PM EDT Tue May 16 2023
We will maintain the small craft advisory for the north zones this
evening. The cold front was dropping through these zones and wind
gusts have been on the increase. A buoy off of Ludington had
gusts in the 15 to 20 knot range over the past couple hours. The
HRRR and NAMNST suggest these sites will make a run at gale force
late this afternoon. Looking upstream we have not seen gale force
winds so for now we will keep the small craft advisory going.
&&
.FIRE WEATHER...
Issued at 207 PM EDT Tue May 16 2023
Conditions were around Red Flag criteria at this time. We will
maintain the current headline. Looking at Thursday, the atmosphere
will be very dry given its Canadian origin. High temperatures may
struggle to reach 75 degrees and the winds may fall a little
short but it is forecast to be close to Red Flag criteria. We will
need to monitor trends concerning Thursdays Red Flag potential.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Red Flag Warning until 8 PM EDT this evening for MIZ038>040-
044>046-051-052-057>059.
LM...Small Craft Advisory until midnight EDT tonight for LMZ848-849.
&&
$$
DISCUSSION...MJS
AVIATION...NJJ
FIRE WEATHER...MJS
MARINE...MJS
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1102 PM CDT Tue May 16 2023
.SYNOPSIS...
Issued at 1101 PM CDT Tue May 16 2023
High pressure will keep much of the cloud cover at bay through
Wednesday. However, the sky will be muted by a thick layer of
smoke aloft, which will drop into the area overnight and linger
through mid week. Temperatures will be close to mid May normals,
with humidity levels on the comfortable side through Thursday
morning.
&&
.UPDATE...
Issued at 812 PM CDT Tue May 16 2023
Backdoor cold front (moving southwest) was located from just west
of Rockford back into northern Indiana at 8 pm. This is forecast
to reach the I-74 corridor between 1-2 am, and into the central
CWA by sunrise. Behind the front, northeast winds will briefly
gust 10-20 mph, and temperatures will drop several degrees. Expect
lows at 50-55F from north to south. Skies will be mainly clear
with some cirrus and the leading edge of the upper level smoke
layer currently over northern IL, tracking south into central IL
after midnight per RAP vertically integrated smoke product. This
will likely not be visible until around sunrise.
25
&&
.SHORT TERM... (Through Thursday)
Issued at 236 PM CDT Tue May 16 2023
Main challenge in this part of the forecast is with sky cover.
Most of the steadier rain has moved into Indiana, though a few
showers linger further west with a weak upper wave currently
located near I-55. This should exit over the next few hours, and
will go with a dry forecast by early evening, continuing through
Thursday afternoon.
Latest satellite analysis shows a thick layer of smoke extending
from Manitoba into eastern South Dakota, then eastward to southern
Ontario. PIREP`s from this area show visibility being impacted as
low as 3,000 feet off the ground, though surface observations are
not showing much in the way of a ground impact. The HRRR is not
handling this smoke at all, likely due to the source region
(Alberta) being outside the domain, but the RAP`s larger domain
appears to have a good handle on it. Initial ribbon of dense
smoke (the east-west band approaching Madison WI this hour) should
be close to I-74 toward late evening and I-70 shortly after
sunrise. Tail end of the projection shows a much larger area of
smoke will descend across the upper Mississippi Valley Wednesday
morning, and extrapolation would bring it into central Illinois
toward midday. With high pressure only slowly drifting across the
Great Lakes, the smoke would not exit too quickly. Thus, minimum
sky cover grids will generally be set to the 35-40% range through
Thursday, despite not much of an actual cloud cover between late
this evening and Thursday morning.
The other feature of note is a backdoor cold front/pneumonia front
that will be pushing southwest from the Lake Michigan region by
early evening. While the wind shift with it should reach I-74
shortly after midnight and Springfield toward sunrise, the actual
"pneumonia" feature of the front (defined as a 1-hour temperature
drop around 16F or greater) would fizzle out before reaching this
far south. Temperatures don`t drop off too dramatically, but
typical mid-May lows in the lower 50s will be widespread in our
area tonight. With more of the easterly flow prevailing due to the
high to our northeast, lows Wednesday light are likely to dip
into the upper 40s east of a Peoria-Mattoon line.
Geelhart
&&
.LONG TERM... (Thursday Night through Next Tuesday)
Issued at 236 PM CDT Tue May 16 2023
Through the weekend, the longer range models are in decent
agreement with upper ridging across the western U.S., keeping the
Midwest in more of a northwest flow. An upper low currently over
northern Saskatchewan will drop into northern Minnesota by
Thursday evening, before swinging east across the Great Lakes
Friday and early Saturday. The GFS is a little more progressive
with this system and its associated front and rain chances, while
the international models linger the rain a bit longer into Friday
night. Overall, not a lot of moisture influx into this system and
instability is not too high, so impacts should not be great. A
weaker wave moving through the upper Mississippi Valley on Sunday
is expected to come through dry.
Heading into early next week, the ridge is expected to begin
building eastward across the CONUS, though the GFS flattens it out
with an upper low that the international models otherwise linger
over the Pacific Northwest. Consequently, it has more of a
south/southwest flow and scattered showers/storms by Tuesday. Will
go with the drier solution at this point
Geelhart
&&
.AVIATION... (For the 06z TAFs through 06z Wednesday Night)
Issued at 1102 PM CDT Tue May 16 2023
VFR skies and winds near/under 10 kt through Wednesday evening as
high pressure builds across the Great Lakes. A backdoor cold
front will shift winds northeast overnight, and remain northeast
through Wednesday.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
WFO ILX
Area Forecast Discussion
National Weather Service Indianapolis IN
1014 PM EDT Tue May 16 2023
.Forecast Update...
Issued at 1014 PM EDT Tue May 16 2023
Little to no change to the forecast with this evening`s update.
Latest surface analysis shows clearing skies across the region with
a moisture starved front pushing in from the north. The main impacts
from this front will be switching light winds around to the
north/northeast tonight and tomorrow. This northerly flow pattern
aloft will advect in haze/smoke in the upper levels from wildfires
in Central Canada. With mainly sunny skies expected, hazy conditions
may occur at times during the day. Not expecting any impacts from
the smoke other than the potential for a colorful sunset. Despite
cooler air advecting in aloft as well, surface temperatures will
likely reach the 70s given abundant sunshine. Upper level smoke may
potentially keep highs a degree or two cooler than guidance, but
overall do not think the smoke will have a meaningful impact on
surface conditions.
&&
.Short Term...(Through Wednesday)
Issued at 105 PM EDT Tue May 16 2023
Somewhat complex pattern is over the region now. One midlevel
perturbation is moving through today and it has origins from an old
MCV/midlevel low that evolved from convection two diurnal cycles ago
along the Texas gulf coast. Its ascent coupled with deep moisture
plume has resulted in widespread rain across southern portions of
the area and intermittent/patchy light rain across the north. This
is now exiting with its most intense convection forming on the
southern flank over Kentucky where instability is greatest.
Meanwhile, another weak perturbation over northeast Missouri is
enhancing rain shower coverage over Illinois and until this clears
the area late this afternoon, at least light showers should
persist. There has been a decreasing trend, so much of this may be
nonmeasurable/sprinkles as it moves through central Indiana mid-
late afternoon. Deepening eastern trough will nudge drier
continental/cP air mass into Indiana this evening ending rain
chances, and resulting in decreasing clouds.
Despite weak cold advection, temperatures tomorrow will be warmer
than the previous couple of days since more radiative component will
be present under clear skies.
There could be some haze by late in the day based on HRRR
smoke model. This is originating from wildfires in the boreal forest
region of Alberta and Saskatchewan. Low level trajectories should
take this southward into the northern Plains, but upper level
flow is more directed over our region. Its unknown how noticeable
this will be at this time, but it may at least enhance sunsets
visually with color due to light scattering from smoke particles.
&&
.Long Term...(Wednesday night through Tuesday)
Issued at 105 PM EDT Tue May 16 2023
Some haze/smoke from Canadian wild fires may be observed Thursday
per HRRR smoke model, and eventually cirrus will move in on the
downstream end of high-level moisture plume preceding the next
system. Temperatures should peak Friday (warmest of the week) due
to strengthening warm advection regime, despite increasing mid-
high clouds.
There remains about a 9-12 hour timing difference with the next
closed mid-upper low and attendant cold front late Friday into early
Saturday. GEFS-weighted clusters are still quicker than the EPS-
weighted clusters. So, we`re still unable to narrow a specific ~6-
hour window of greatest precipitation chances/intensity, and
will continue a fairly broad-brush approach of precipitation chances
between Friday afternoon and Friday night.
These patterns of split flow and embedded closed lows are
notoriously difficult for models especially at this time range. We
will refine timing over the next few days. What we can say now is
the overall way in which synoptic-scale forcing interacts with
the warm sector, a frontal band of showers and thunderstorms is
the most likely outcome. Again, there is about a 6-hour window for
the bulk of the precipitation. Furthermore, some lightning may
accompany this but instability should be tempered by the track of
the low and higher-latitude path of steeper midlevel lapse rates.
Deep moisture and nearly moist adiabatic profiles are indicated
for our area. Thus, the risk of severe convection currently
appears low.
Post-frontal air mass should be slightly cooler (but near
seasonal normals) and less humid into early next week. We will be in
northwesterly flow aloft albeit modest at this latitude. One more
shortwave trough may pass with some clouds but dry continental
air mass should preclude precipitation. Temperatures warm above
normal toward the middle of next week as medium-range ensemble
guidance shows mean troughing in the east deamplifying and
positive midlevel height anomalies across the higher latitudes of
the U.S. and Canada increasing substantially.
Early indications are that this quiescent synoptic pattern will
carry into the Day 8-14 period with generally near or above normal
temperatures and below average precipitation.
&&
.Aviation...(00Z TAF Issuance)
Issued at 734 PM EDT Tue May 16 2023
Impacts:
* Isolated showers ending, VFR conditions expected through the period
* Light winds under 10 kts, periods of variable winds
* Hazy skies tomorrow from Canadian wildfire smoke
Discussion:
Latest satellite and radar imagery shows rain and clouds from
earlier finally pushing off to the east. Scattered high clouds will
linger through the rest of the evening before clearing out later
tonight. Weak front pushing in from the north will switch winds from
west to northerly overnight, but speeds should remain under 10 kts.
Subsidence and dry air associated with high pressure tomorrow should
keep VFR conditions through the rest of the period. Satelitte imagery
does show smoke from wildfires in Canada being transported south
over the region tomorrow from northerly upper level flow. While no
impacts will be seen at the surface, it will make skies hazy at
times tomorrow.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...CM
Short Term...BRB
Long Term...BRB
Aviation...CM
Area Forecast Discussion
National Weather Service Northern Indiana
613 PM EDT Tue May 16 2023
.SYNOPSIS...
Issued at 243 PM EDT Tue May 16 2023
Dry weather will prevail through Thursday night with clear to
partly obscured skies as a result of smoke from Canadian wildfires.
Seasonable temperatures can be expected through the rest of the
work week aside from Wednesday, which is cooler as a result of
this evening`s cold front. Our next chance for rain is Friday with
a few thunderstorms also possible.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 243 PM EDT Tue May 16 2023
A strung out area of vorticity from the Ohio Valley into the Middle
Mississippi Valley coincident with a thermal gradient in the Ohio
Valley serves as a path that the low pressure system that brought
rain to our area travels along. It will continue to travel to the
east this afternoon allowing drier air to sink in from the north and
for clouds to dissipate. Meanwhile in Canada, an upper low pressure
system slowly sinks south and an area of vorticity pinwheels south
around the upper low`s periphery. As the area of vorticity dives
southward, it pushes a boundary southward along Lake Michigan. Cold
air is able to come in tonight behind the boundary and will allow
for a cooler Wednesday with minimal cloud cover as a result.
However, smoke from Canada is expected to filter into the area in
some capacity likely limiting Lows tonight will be slightly cooler
than last nights, but still in the low 40s to low 50s. Highs
Wednesday will only be in the mid 60s to low 70s. Height rises on
Wednesday also signal the arrival of surface high pressure, which
brings dry weather through Thursday, but again we`ll have the smoky
haze around as long as the RAP smoke model is correct.
&&
.LONG TERM...(Thursday through Tuesday)
Issued at 243 PM EDT Tue May 16 2023
With high pressure now to the east of the forecast area,
temperatures will be able to warm back to around normal, in the low
70s, for Thursday. Continued dry air will provide plenty of sunshine
for the forecast area. In fact, even without adjusting model dew
points for expected low level lapse rates, MinRH values are already
falling below 25 percent. This is as 30 degree dew points pair with
temperatures rising into the low 70s. However, 10hr fuels still
appear rather wet at greater than 10 percent and sustained winds,
and gusts for that matter, remain below 20 mph. These conditions
will need to be watched going forward for possible elevated fire
danger.
For Friday, Thursday`s mid level ridging will be overtaken by an
upper level low pressure system arriving from Central Canada. A cold
front still looks too fast on the GFS when compared to the ECMWF/NAM
consensus. Depending on the arrival of the cold front, there`s a
chance highs in the upper 70s might be too warm for two to three
tiers of counties southeast from Lake MI, but low to mid 70s appear
more reasonable there. Again, this will depend on the timing of the
cold front through the area, and therefore, the amount of
instability that can be generated, but could see some
showers/thunderstorms form with the most likely area of their
formation being south of US-24. Instability being modeled at this
juncture doesn`t appear very strong so the chance for severe weather
appears low Friday afternoon.
The aforementioned upper low passes by the area on Saturday allowing
for cooler temperatures and a drier airmass. Therefore, have removed
Saturday`s precipitation chance. It`ll be warmer ahead of a frontal
boundary arriving around evening time, but without a clear moisture
connection, expect a dry frontal passage. The beginning of the next
work week also looks dry as high pressure follows the aforementioned
frontal passage.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 613 PM EDT Tue May 16 2023
A cold front will drop through from the north this evening with
winds veering to the east-northeast overnight into Wednesday. A
very dry airmass will ensure dry/VFR conditions through the TAF
cycle and beyond otherwise.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Roller
SHORT TERM...Roller
LONG TERM...Roller
AVIATION...Steinwedel
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Follow us on Facebook...Twitter...and YouTube at:
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Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
623 PM CDT Tue May 16 2023
.SHORT TERM...
Issued at 215 PM CDT Tue May 16 2023
Through Wednesday night...
The much advertised lake enhanced cold front is racing south
across Lake Michigan early this afternoon. Temperatures ahead of
the front are warming into the mid to upper 70s already early
this afternoon with the anticipation that some places even reach
the lower 80s. The forecast for the cold front arrival time
remains unchanged from the morning update with the expectation
that it reaches far northeast Illinois between 4-5pm, Chicago
between 5-6pm, and northwest IN and the outer IL suburbs 6-7pm.
Cannot rule out a slightly earlier arrival. Regardless, the
message remains the same, if planning to spend time outdoors later
this afternoon into the evening be sure to take a jacket along
with in anticipation of a 15-20+ degree drop and gusty winds to
20-30 mph in the immediate wake of the cold frontal passage! Lows
tonight dip into the lower-mid 40s north of I-88 and upper 40s to
near 50 south.
The weather looks quiet tonight through Wednesday night as
surface high pressure becomes established over Lake Superior. This
will result in continued easterly flow through the day.
Accordingly lake cooled air will keep high temperatures mid 50s
along the shore and lower 60s across the Chicago metro. Areas
further inland may still manage to warm into the lower to mid 70s.
Last item worth discussing is the smoke layer aloft drifting
southeast from Alberta wild fires. A thin ribbon of smoke is
expected to drift south out of Wisconsin over the area this
evening. Depending on how quickly it gets here it may result in a
pink tint to the sun as it is setting. This ribbon continues south
of the area overnight. Looking at the RAP Vertically Integrated
Smoke product a broader area of smoke aloft is forecast to move
back into the area tomorrow morning/early afternoon that persists
the next couple of days and resulting in a milky/hazy appearance
to the sky. Always tricky to account for this in the sky cover
grids. While not ideal, for now have increased vales to 45 percent
so that the forecast reads "partly cloudy" during those periods.
Petr
&&
.LONG TERM...
Issued at 300 PM CDT Tue May 16 2023
Thursday through Tuesday...
Key Forecast Message:
* Showers with a limited threat of thunderstorms Thursday night-
Friday ahead of the next cold front
* Upper level smoke from wildfires in Alberta likely persisting
through Thursday
A primarily quiet west-northwest flow aloft pattern will be in
place through early next work week. The exception to this and main
period of interest will be associated with a potent mid-upper low
and its associated cold front embedded in a weak surface trough.
Thursday and much of if not the entire evening will be dry, with
maybe a few showers sneaking into the far northwest CWA toward
midnight. If the upper level smoke isn`t too thick on Thursday,
highs are pegged to reach the mid to upper 70s inland, warmest far
west/southwest, and 60s Illinois shore due to southeast winds and
an afternoon lake breeze backing winds more easterly.
The strongest forcing with the mid-upper low will lag the front
Thursday night into Friday and focus just to our north. That said,
frontal convergence near and maybe even just behind the front and
upper level jet support will team up with a ribbon of higher
column moisture to produce fairly widespread shower coverage.
There is variance in the guidance in the exact frontal timing,
with an overall slightly faster frontal approach and passage noted
in the past 24 hours or so. If the fastest timing verifies,
showers should end northwest to southeast mid day through mid
Friday afternoon. Regarding thunder chances, weak mid-level lapse
rates and progged meager elevated instability should keep
lightning instances isolated/sporadic at best if not entirely
preclude lightning. Low but relatively better chances may include
the overnight Thursday night period in parts of northern IL and
then near/southeast of I-55 Friday afternoon depending on the cold
frontal timing.
Following forecast highs in the 70s ahead of the front on Friday,
there will be a healthy cool-down behind it, but not nearly the
magnitude and quickness of this (Tuesday) evening`s lake enhanced
front. Forecast lows are in the upper 40s-lower 50s Friday night-
early Saturday. A series of high pressure systems will bring
quiet weather in aforementioned west-northwest flow aloft.
Temperatures will be near to slightly perhaps slightly below
normal Saturday, coolest lakeside, warming back above normal
Sunday ahead of another strong lake breeze (could be another lake
enhanced front in this setup). The pattern will repeat itself on
Monday and Tuesday. Beyond current day 7 (next Tuesday) may be
next opportunity for rain, though all in all, not yet seeing signs
of a change to an active/stormy pattern.
Castro
&&
.AVIATION...
For the 00Z TAFs...
Northeasterly winds will gust 20-25 kt for the first few hours of
the TAF period behind a lake-enhanced cold front before
decreasing in magnitude by 03Z. Thereafter, east-northeasterly
winds of 10-15kt will prevail through the TAF period. Per experimental
RAP-SMOKE guidance, extensive wildfire spoke trapped above FL250
appears on track to stream over the terminals tomorrow. So, opted
to introduce SCT250 at all terminals for an expectation for
opaqueness in the sky tomorrow.
Borchardt
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...IL nearshore waters until 7 AM Wednesday.
Small Craft Advisory...IN nearshore waters until 7 AM Wednesday.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
645 PM EDT Tue May 16 2023
.SHORT TERM...(This afternoon and tonight)
Issued at 130 PM EDT TUE MAY 16 2023
Cold front dropped south through the region today, kicking off a
period of cloud cover near Lake Superior and gusty winds CWA-wide. A
majority of sites observed winds gusting above 20mph while
temperatures cooled from north to south. By publishing this, most of
the northern half of Upper Michigan was in the 40s or 50s, while the
south half was still in the 60s. Dry air building in behind the
front has helped scour out cloud cover save for some patches in the
interior west and north-central.
As we progress through the remainder of the afternoon and overnight,
cloud cover will mix out and winds will weaken, going light and
variable across a majority of the forecast area. The drier airmass
will allow for a colder night then last, and most areas in the
interior are expected to dip into the low 30s or high 20s. Together,
this should support patches or areas of frost.
.LONG TERM...(Wednesday through Tuesday)
Issued at 447 PM EDT TUE MAY 16 2023
Slightly below normal temperatures and near normal precipitation is
forecast for the extended period. Precipitation chances are focused
in the late Thursday (west) into early Saturday period (east) as an
area of low pressure tracks across the region. A cold front on
Sunday could bring a few showers, but the bigger story is another
very dry ridge moving across the area. Regarding fire wx potential,
Thursday seems to have the worst combination of elevated winds and
low RHs.
Starting with Wednesday, dry surface ridging results in light winds
and mostly sunny skies that should result in RHs dipping below 20%
in spots. RAP guidance shows a plume of smoke tracking into our area
Wednesday morning that could limit high temps or at least make it
feel more comfortable. A ~35 knot southwesterly low level jet tracks
across the area Thursday morning (west) and Thursday evening (east).
This should result in gusty winds ramping up as the sun comes up
Thursday morning resulting in some low level mixing. Think this good
mixing and dryness should continue until the cold front and precip
arrives. The strongest winds appear to be across the east (gusts to
30 kts) during the afternoon and evening hours when RH values below
30% lead to bonafide Elevated Fire Wx Conditions. Nighttime recovery
is also questionable ahead of the frontal boundary since southerly
flow should keep the boundary layer well-mixed. I tried to keep RHs
low until the FroPa occurs to reflect this.
Showers and perhaps a few rumbles of thunder are expected along and
immediately behind the FroPa. The 12z 3km NAM brings the front into
IWD shortly after 18Z, CMX around 21Z, and MQT/IMT just before
midnight, and the far eastern UP around sunrise on Friday. Currently
forecast PoPs probably move east a bit too fast, but I felt fire wx
concerns were more worthy of my time investment. Precip chances ramp
up again as the cold core upper level low Friday into Friday night,
but there should be a few hours of drying between these two
features. Ensemble means have total QPF amounts around 1/2 inch
across the western 2/3rds with lighter amounts across the east. A
cold front Sunday morning scours out any remaining moisture as a
much drier air mass associated with a 1025+ mb ridge moves into the
region.
This drier air mass is likely to bring renewed fire wx concerns.
Fortunately winds appear mostly light, but there are some higher
winds on Sunday as the ridge builds and perhaps on Tuesday as the
high shifts away from the area. The lowest RHs should be on Monday
when the ridge is centered over our area with light winds and
afternoon lake breeze development.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 645 PM EDT TUE MAY 16 2023
A dry airmass moving into the region will support clear skies at all
terminals with VFR conditions in this TAF period.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 447 PM EDT TUE MAY 16 2023
Northerly winds are currently around 20 to 25 knots across southern
Lake Superior this afternoon, then fall below 20 knots this early
this evening. With ridging over the Upper Great Lakes Wednesday,
wind gusts remain below 20 knots until the afternoon across the far
western lake as a low pressure approaches. Easterly gusts around 20
knots Wednesday afternoon veer southerly Wednesday night and
increase to around 20 to 25 knots over the north central lake as a
low level jet passes over the lake. Thursday, southerly gusts around
20 to 30 knots are expected, with some higher gusts possible across
eastern Lake Superior during the evening immediately ahead of the
cold front. Behind the front Friday, winds generally out of the
northwest continue to gust to around 20 knots. There is some
forecast uncertainty into the weekend but a period of lighter winds
is favored as high pressure slowly builds in Friday night. WSW gusts
increase again to around 25 kts on Saturday ahead of another cold
front expected Sunday morning.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JTP
LONG TERM...EK
AVIATION...07
MARINE...EK
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 309 PM CDT Tue May 16 2023
Key Messages:
- Next shower and thunderstorm chances Wednesday night into
Thursday night.
- Dry Friday through Monday with highs near to slightly above
normal.
Tonight and Wednesday:
Relatively quiet weather conditions are expected for the next
24-36 hours as a low-level ridge axis progressively weakens over
the mid-MO Valley. A plume of mid/upper-level smoke originating
from wildfires over western Canada is spreading south through the
northern Plains and upper-MS Valley this afternoon with the smoke
moving into our area tonight into Wednesday. RAP and HRRR
forecasts suggest that the majority of smoke will remain suspended
aloft, though some potential will exist for reduced air quality
and minor visibility reductions at the surface. Otherwise, expect
slightly warmer conditions Wednesday with highs in the lower to
mid 80s.
Wednesday night into Thursday night:
A mid/upper-level low will progress from Saskatchewan and
Manitoba into the upper Great Lakes during this time period with
an associated surface cold front moving south through the mid-MO
Valley Thursday. Height falls/dynamic forcing for ascent attendant
to the upper-air system coupled with low-level convergence/uplift
along the front are expected to foster widely scattered to
scattered showers and thunderstorms along and ahead of the front.
No severe weather is expected with rainfall amounts of less than
0.25" at most locations.
Highs Thursday will be modulated by clouds and areas of rain with
readings generally in the mid 70s to lower 80s.
Friday through Monday:
A slightly cooler air mass will move into the region Friday on the
backside of Thursday`s cold front with highs in the upper 60s to
low 70s. Developing south winds Saturday will draw warmer air into
the region with highs bouncing back into the mid to upper 70s. By
Sunday, model differences exist in the strengthen of a midlevel
trough from Hudson Bay into the Great Lakes, and the effect of
that feature on the surface pattern. The deterministic ECMWF
depicts the lowest midlevel height field, which in turn drives a
surface cold front into the mid-MO Valley, which in turn would
bring a chance of rain to the area. The deterministic GFS and
Canadian models suggest the midlevel trough will be weaker with
no frontal intrusion, and reduced precipitation chances. The
GFS/Canadian model solutions are supported by the NBM, so we will
not include any precipitation chances. Highs Sunday will be in
the upper 70s to low 80s. Similar conditions are expected Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 532 PM CDT Tue May 16 2023
VFR conditions expected through the period.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Mead
AVIATION...DEE
Area Forecast Discussion
National Weather Service Pocatello ID
227 PM MDT Tue May 16 2023
.SHORT TERM...Tonight through Fri afternoon. Showers and
thunderstorms just in the last hour have developed on weather
radar, mostly in the northeast corner of the forecast area so far.
This should continue into the early evening, then some morning
showers are possible in the central Idaho mountains on Wed, if
the HRRR is to be believed. There is some moisture available, but
good instability does not occur until Wed afternoon. And this
applies not just to the central Idaho mountains, but all over the
forecast area, with increased available moisture and continued
good shear. At this time, do not expect any severe conditions on
Wed afternoon/evening. The pattern creating this weather is very
slow in changing with showers and thunderstorms continuing at
least through Thu evening. The low finally exits to the east on
Fri, with stronger warming developing under a high-amplitude ridge,
with temperatures over the weekend warming in populated areas to
above/around 80 degrees even in places as far north as Rexburg. On
Friday, the thunderstorm threat falls off, but the heating does
not eliminate the threat totally; the central Idaho mountains and
the southeast highlands have a slight chance level of threat.
Wind outside of thunderstorms shouldn`t amount to much. Yesterday,
for Thu an organized trough was producing moderate wind in the
Snake River plain. This is not the case with the morning guidance
run, so will need to keep an eye on if this is a permanent change.
Messick
.LONG TERM...Friday night through next Tuesday. Ensemble means and
cluster analysis data remain in good agreement showing upper ridging
dominating the local weather scene Friday night into Sunday. As a
result, we continue to anticipate the warmest temperatures of the
next week to occur this weekend, with daytime highs reaching the 80s
at lower elevations and 60s/70s at all but the highest mountain
elevations (where temps will top out in the 50s). Sunday should be
the warmest day, and probabilities of exceeding 90F remain in the 40-
60 percent range across portions of the Lower Snake Plain and
Eastern Magic Valley. Probabilities of exceeding 80F in the Wood
River and Big Lost River Valleys are running between 50-80% from
roughly Ketchum and Mackay south. Overnight lows will also be well
above normal, remaining above freezing across the vast majority of
the area, excluding only the typical high-elevation coldest spots.
Of course with this building warmth through the weekend, flooding
will continue to ramp up for areas still dealing with snowmelt (more
on that in the Hydrology section below). While coverage/chances of
showers and thunderstorms will decrease this weekend under the upper
ridge, they won`t shut off entirely. Remnant moisture trapped under
the ridge appears sufficient to team with diurnal heating over the
higher terrain to support some afternoon/evening convection.
Heading into early next week, considerable uncertainty exists with
the evolution of an upper low over the PacNW/southern BC. H5 cluster
analysis shows a roughly 60%/40% split on a more progressive system
pushing east through the Northern Rockies vs. a closed low spinning
over the PacNW for several days, ejecting shortwaves across the area
in a southwest flow aloft. The former scenario would support a
stronger cold frontal push and more consolidated precip event early
in the week, followed by moderated cooling and at least a brief dry
period. The latter would support continued warmer conditions and
daily shower/thunderstorm chances downstream of the low. This latter
scenario (warmer/wetter) could further exacerbate flood concerns
next week, and thus we`ll be keeping a close eye on this pattern
evolution in the days ahead. KB
&&
.AVIATION...Expecting less -TSRA activity with less available
moisture, although instability is quite good. It is the reason why
gusty wind is expected this afternoon and evening. Some late night
and morning -SHRA are possible over the mountainous regions,
including KSUN and KDIJ. By Wed afternoon, moisture levels in the
atmosphere are up and the low overhead produce another round of
-SHRA/-TSRA in the afternoon and evening. This has the potential
to be stronger with more rain, but it should not produce
significant CIG or VSBY impacts at the airdromes. Chief hazard
will be lightning and shifting wind. Messick
&&
.HYDROLOGY...With the gradual warming trend continuing, so do the
flood concerns from snowmelt across the area. The main changes today
were to upgrade the Flood Watch for the Henry`s Fork near Rexburg to
a Flood Warning, as flood stage is expected to be reached Wednesday
morning. In addition, an Areal Flood Warning was issued for much of
Bear Lake County, replacing the Areal Flood Advisory, as local
Emergency Management reports the flooding has escalated along the
Thomas Fork near the WY border and also in many canyons emerging
from the Bear River Range in western portions of the county.
Otherwise, the going suite of flood headlines remain unchanged. The
Big Wood River at Hailey is now expected to reach moderate flood
stage earlier (Thursday) than previously forecast. The latest
forecasts have delayed the Big Lost at Howell Ranch reaching flood
stage by a couple of days (now Saturday), so have maintained the
Flood Watch there. Antelope Creek remains just under flood stage.
Per coordination with local Emergency Management, will hold off on
issuing a Flood Warning for now, but anticipate needing one in the
next day or two as flood stage is reached. Camas Creek has dropped
over the past 24 hours, with no impacts of note there.
The continued warmth into the weekend will drive further rises on
rivers and streams still being fed by snowmelt. No noteworthy cool
downs are currently anticipated over the next week, so look for the
runoff to continue to drive high flows. KB
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$