Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/04/22
Area Forecast Discussion
National Weather Service Bismarck ND
935 PM CDT Sun Jul 3 2022
.UPDATE...
Issued at 935 PM CDT Sun Jul 3 2022
We issued a Flood Watch from Sioux and Emmons Counties eastward
through Logan, McIntosh, LaMoure, and Dickey Counties in response
to potential training, clustered convection moving through that
area the next 3-6 hours. Low-level moisture transport focused in
that area and high precipitable water values around 1.5 inches is
a favorable heavy-rainfall and potential flash flooding setup in
that area. Otherwise, with this update we only made minor changes
to the forecast. Severe-storm risk is ramping up as expected with
two primary regimes, a mix of supercells and bowing segments that
will enter southwestern ND shortly and the more clustered/training
storms in far south central ND lifting northward with time.
MESOSCALE DISCUSSION Issued at 807 PM CDT Sun Jul 3 2022
Early evening surface analysis reveals a surface low southeast of
Billings, MT, and a quasi-stationary frontal zone extending to the
east-northeast across southeastern MT and into southern ND roughly
along the I-94 corridor. An old outflow boundary is located across
northern SD, and there`s a subtle area of slightly lower dewpoints
(lower versus middle 60s F) in northern SD near that boundary,
and the 00 UTC Aberdeen RAOB sampled weak bouyancy in that corridor
in comparison to the moderate MLCAPE sampled at Bismarck. This
likely explains why the storms in north central/northeastern SD
have had a difficult time intensifying -- but also suggests that
as storms gradually propagate and/or develop into south central
and southeast ND along and south of the quasi-stationary boundary
that they will be in a more favorable thermodynamic environment
for intensification. Both visible satellite imagery and visual
observations suggest attempts at in-situ initiation near Bismarck
near the boundary too, and the minimal MLCIN sampled on our 00
UTC RAOB suggests storms may form the next 1-2 hours there, too.
Storm-scale interactions/mergers and upscale growth may temper
peak hazard magnitudes somewhat with this activity, if enough
initiation occurs, but otherwise strong deep-layer shear favors
large to possibly very large hail given moderate CAPE.
Meanwhile, severe storms including a developing bowing complex in
east central MT and a recently-developed supercell in southeastern
MT near the surface low are all propagating toward ND. Dewpoints
in the middle 60s F exist over a wide berth of western/central ND
downstream of these storms, and very strong deep-layer shear will
favor both supercells and bowing complexes, the latter of which
is further favored by easterly low-level flow and related gust-
front maintenance, large DCAPE, and increasing low-level shear.
The one uncertainty with regard to how long-lived any bowing
complex may be is how much convection develops ahead of it in
southern ND in vicinity of the quasi-stationary boundary. If messy
modes develop in the inflow region of the approaching bowing
segment(s), then they may not be as long-lived, but if there is
less opportunity for unfavorable storm-scale interactions, then a
long-lived bow echo could impact western and into central ND. This
is a subtle detail related to the coming event, but regardless,
an increase in storm coverage and severe-storm risk is still
anticipated the next several hours. Finally, note that there is a
non-zero tornado risk with any of the storms in western and south
central ND, especially as low-level shear and SRH increase toward
and after sunset, but the potential for upscale-growing and/or
messy storm modes may tend to limit that risk somewhat.
UPDATE Issued at 605 PM CDT Sun Jul 3 2022
Moderate bouyancy with minimized MLCIN is present across southern
and western ND late this afternoon owing to surface dewpoints in
the middle to upper 60s F and steep midlevel lapse rates. A weak
east-west-oriented boundary is in place across southern ND, but
visible satellite imagery has shown little in the way of attempts
at convective initiation in our forecast area the last 60 minutes.
Larger-scale ascent approaching from both the west and south will
likely serve as the impetus for increasing convective coverage
and related severe-storm risks in the late evening in southwest
and south central ND, as many CAMS including recent HRRR cycles
have suggested. Moreover, extrapolation of the ongoing supercell-
bowing complex transition near Jordan, MT, as of 23 UTC would have
it reaching the ND/MT state line between before 02 UTC. Thus, we
expect a rapid increase in severe storm risk in the mid to late
evening over a wide portion of our forecast area. Where forecast
considerations are concerned, we increased coverage and extent of
60-80 percent PoPs tonight with this update, and blended recent
observed trends into the early evening hourly forecast elements.
&&
.SHORT TERM...(This evening through Monday)
Issued at 219 PM CDT Sun Jul 3 2022
Thunderstorm chances and the potential for severe storms highlight
the short term forecast.
Currently, an upper level low continues to spin over the far
eastern Pacific with a broad southwest flow from much of
California into the northern Rockies with an upper level ridge
over the northern High Plains into the western Dakotas.
At the surface, low pressure was situated over north central
Wyoming with pressure falls onto southeast Montana and a warm
front eastward through central South Dakota. Another stationary
front was situated from the Northern Rockies eastward through
northern North Dakota. A weak wave was moving over the apex of the
upper ridge, producing showers over western North Dakota. North of
the stationary more widespread showers extended from the Northern
Rockies (where a shortwave was lifting northward into southern
Alberta) east across northern Montana and into northwest ND.
Surface pressures over the local area had been rising through most
of the morning and have just began to slowly fall.
A marginally unstable atmosphere with MLCAPE values of 1000-2000
J/KG over the southern half of the state will only continue to
increase through the afternoon and into this evening. Deep layer
shear remains strong across the forecast area. Late this afternoon
into early this evening forecast soundings over central ND
indicate little capping. The question is whether or not there is
a trigger to initiate convection. Besides the numerous shortwave
impulses propagating through the upper flow, a strong upper level
jet moves over the area and strengthens tonight. We are thinking
that the forcing from the right entrance region of the jet may be
enough to initiate convection over south central into southeast
North Dakota this evening. Some CAMS are indicating this, but
there are still varying outcomes as to where/when and some do not
develop convection there this evening. Another area of concern is
western ND this evening. Beginning in the southwest early this
evening as convection fires off the higher terrain of northern
Wyoming and southeast Montana. Some of the CAMS have shown more
discrete convection initiating here, which would increase the
threat of large hail and possibly a tornado. The question for us
would be whether or not storms, if initially discrete, continue
that way as they move into southwestern ND. Or if they cluster or
grow upscale before reaching the southwest, the hail threat would
be smaller but with an increased wind threat. Finally, late
tonight there is still a signal in some of CAMS of convection
firing off the Rockies in central MT and making it into western
North Dakota late this evening and progressing across the forecast
area overnight. HREF UH neighborhood probabilities from 00 UTC
and 12 UTC really drop off once they cross over into North Dakota,
so hopefully the wind threat diminishes as advertised here.
However the SPC Enhanced Risk does extend through much of the
southwest. Here the mode would most likely be upscale with bowing
segments by the time it reaches North Dakota, so the tornado
threat would be lower, but significant winds would still be
possible.
With anomalously high PWATS, the location of the surface low and
the weak upper level flow and a stationary front draped over the
forecast area, we will continue to message the potential for
localized flooding due to very heavy rain with thunderstorms that
develop. There is enough uncertainty as to if storms develop and
areal coverage south central and southeast this evening, as well
as the progressive nature of convection moving into the west late,
to hold off on a flood watch. But given we may see a few rounds
and the late timing for the last round, can not completely rule
out a watch this evening.
Monday morning we may still be dealing with lingering convection
overnight tonight, but this should be non-severe by then. There
are some differences in the medium range models, but in general
we get a period of cooler northerly flow on Monday, with probably
some widespread low ceilings through the morning. It`s then a
question as to how things clear out Monday afternoon and if we can
destabilize enough again for another chance of strong to severe
storms, as there is another decent shortwave moving through the
forecast area. At this time CAMS that go out that far vary from
little or nothing, to strong to severe storms central and east. Oh
and possibly storms moving into the west late. I think it`s best
to revisit this again after tonight.
.LONG TERM...(Monday night through Sunday)
Issued at 219 PM CDT Sun Jul 3 2022
Thunderstorm chances continue nearly each day through the long term
period, with the possibility of severe weather. Warmer temperatures
are expected toward the end of the period.
Surface high pressure over Canada continues to drop south into the
forecast area Monday night. Instability continues to trend farther
south, with the south and west being the better areas to see
enough instability for overnight thunderstorms Monday night. On
Tuesday the cooler surface high slides east and we begin a period
of broad upper level ridging over the area, but with a continued
barrage of shortwaves through the mean ridge position. This will
bring warming temperatures mid to late week with on and off
thunderstorm chances. Our recent strong bulk shear does drop off a
bit but instability will not be lacking, so mostly diurnally
driven thunderstorm chances remain in the forecast each day, but
with a lot of uncertainty in timing. placement and coverage each
day. The western trough does eject into the Northern Plains by the
end of the forecast period, perhaps bringing a better chance of
more widespread thunderstorms next weekend.
The upper low mentioned in the short term discussion moves onto the
Pacific Northwest coast on Monday with downstream ridging situated
over the western Dakotas. Upper level ridging continues to build
over the area through mid week, lifting the Pacific Northwest
upper low northeast through Alberta and into the central Canadian
Prairie Provinces,and keeping a broad southwest flow over the
local forecast area. Thereafter, we may see a day or so of zonal
upper flow before another western Pacific trough develops with
downstream ridging over the Rockies and into the Plains states.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 935 PM CDT Sun Jul 3 2022
Scattered to numerous showers and thunderstorms will spread across
most of western and central ND tonight. Local IFR conditions,
large hail, and damaging winds are expected with the most intense
storms. Showers and storms will diminish by 12 UTC, but there`s a
high, ~60% probability of MVFR to IFR stratus developing across
much of western and central ND late tonight into tomorrow.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 6 AM CDT /5 AM MDT/ Monday for NDZ045>048-050-
051.
&&
$$
UPDATE...CJS
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...CJS
Area Forecast Discussion
National Weather Service Duluth MN
653 PM CDT Sun Jul 3 2022
.DISCUSSION...(This evening through Saturday)
Issued at 348 PM CDT Sun Jul 3 2022
Summary: Active pattern continues this week with several
opportunities for showers and thunderstorms. A few storms tonight
and Monday may be severe. Temperatures gradually warm up during
the week.
A surface warm front stretched from near Grafton, ND to Bemidji,
MN to a little north of Moose Lake to near Manitowish Waters, WI
as of 19Z. A 20-25 kt southerly low-level jet was located over
central Minnesota per RAP analysis at 19Z. The LLJ will continue
to trek northeastward this evening and strengthens to 25-30 kts by
06Z. There has been enough convergence along the northern
periphery of the LLJ to keep showers and a few thunderstorms
percolating over central, east-central, and north-central
Minnesota into northwest Wisconsin this morning into early
afternoon. GOES-East water vapor imagery reveals an anti-
cyclonically curved jet streak and shortwave trough over the
eastern Dakotas and western Minnsota. Persistent convection in
eastern South Dakota into western Minnesota is in the right
entrance region of the jet streak.
Convective parameters are not impressive at this time. Weak 0-1km
MLCAPE of 250 J/kg was found over most of the Northland. Abundant
cloud cover has limited destabilization this afternoon. A slight
increase in instability is expected over portions of central and
north-central Minnesota by this evening into the 500-1000 J/kg
range. Deep layer shear is sufficient for storm organization and
areas where strong storms are most likely feature cyclonically
curved hodographs. If a few storms can tap into that stronger
instability, a few damaging wind gusts and hail of penny- to half
dollar-size are possible. In general look for precipitation
coverage to continue to slowly increase into this evening as the
jet streak and associated shortwave trough pushes farther eastward
into the Upper Midwest. There is ample moisture available for
heavy rain this evening through the overnight. Areas in central
Minnesota east into the I-35 corridor have the greatest risk of
excessive rainfall and flash flooding should storms repeatedly
move over the same locations.
Upstream over the Dakotas and eastern Montana, storms are
expected to develop this afternoon and may coalesce into one or
more eastward-propagating MCSes. If they persist, they will move
into central Minnesota before 12Z Monday and may present a risk of
damaging wind gusts in the Walker to Brainerd area and points
west. Those storms will continue to propagate eastward Monday
morning and will gradually weaken with time by late morning and
early afternoon.
A second warm front is forecast to lift into the Northland during
the morning and afternoon hours Monday another round of strong to
severe storms is possible along and south of the boundary. By
late afternoon, MLCAPE along and south of the front will increase
to 1000-2500 J/kg over central Minnesota east into northwest
Wisconsin. Deep layer shear will be a little lower than this
afternoon, but still sufficient for organized storms, 30-50 kts in
the 0-6 km layer. Steep mid-level lapse rates of 7-7.5 C/km will
support a large hail threat with storms that develop. Nearly
straight hodographs suggest a potential for splitting storms.
Working against the potential for severe storms is the persistent
low-level jet and mid-level subsidence during the late morning
and afternoon hours. The persistent jet may support widespread
showers and storms throughout the morning, which would limit the
destabilization and may also result in too many storms sharing the
available instability. The subsidence may limit convection over
central MN east into northwest WI through the afternoon, with the
focus for convection over far northern Minnesota and northwest
Ontario, where convergence is maximized and the timing of
shortwave is more favorable. That area will see less instability,
only 500-1000 J/kg. Many unknowns at this point and it seems
prudent for people to plan ahead in case storms threaten tomorrow.
Showers and storms may linger into Tuesday morning as the warm
front pushes south as a cold front. Tuesday afternoon is shaping
up dry with increasing sunshine expected. Rain and storm chances
return as early as late Wednesday morning and will persist off and
on through next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 653 PM CDT Sun Jul 3 2022
Overall confidence with this set of TAFs is lower than average
with poor model agreement. Confidence is higher over the next 6
hours, but drops beyond that. A complex of storms is expected to
develop across the Northern High Plains tonight and track east
Monday morning. There remains uncertainty on the timing and
location of this complex and how strong it will be. The HRRR seems
to be handling the current shower and storm activity, so leaned
more heavily on it for the timing of the rainfall Monday morning.
Most of the activity should push east of the region by early
Monday afternoon, but may linger in spots. A period of IFR or
lower CIGs will be possible Monday morning, especially where
rainfall is received. VSBYs may drop to IFR or lower in heavier
areas of rain.
&&
.MARINE...
Issued at 348 PM CDT Sun Jul 3 2022
A relaxed pressure gradient will persist over western Lake
Superior early this week. Winds will generally be in the 5 to 15
knot range. There will be a few chances of showers and
thunderstorms, and there`s a small chance some of the storms will
be severe. The strongest storms will be capable of pea- to penny-
size hail, wind gusts to 40 knots, frequent cloud-to-water
lightning, and heavy rainfall which may reduce visibility to less
than 1 mile at times.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 53 67 53 70 / 80 70 50 10
INL 56 72 57 76 / 60 60 50 10
BRD 65 81 62 77 / 80 60 40 10
HYR 62 81 57 76 / 60 70 60 10
ASX 54 73 50 69 / 70 60 60 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
DISCUSSION...Huyck
AVIATION...BJH
MARINE...Huyck
Area Forecast Discussion
National Weather Service Grand Rapids MI
808 PM EDT Sun Jul 3 2022
LATEST UPDATE...
Aviation
.DISCUSSION...(This evening through next Sunday)
Issued at 329 PM EDT Sun Jul 3 2022
- Independence Day Storms Late In The Day -
My thinking has not changed from a few hours ago for Independence
Day. I expect, with high confidence, that it will be dry most of
the day. Precipitation would most likely enter far southwestern
Lower Michigan after 7 PM and then spread east or southeast.
Precipitation would be predominantly showers but some embedded
thunderstorms are possible. A greater risk will be for heavy rain
in the early morning hours Tuesday. This heavy rain threat will be
greater west of US-131 and greatest near the Lake Michigan shore.
Given the numerous activities scheduled for Independence Day and
the potential for convection here, it seems prudent to address our
latest thinking on convection impacts for tomorrow. It seems
there would be a convective complex moving across Iowa during the
daytime, aided by a 40 knot low level jet aimed at western Iowa
early in the day then more so towards eastern Iowa by late
afternoon. This is the glitch for severe storms in Southwest
Michigan tomorrow. Both the RAP model and NAM show the low level
jet axis not crossing Lake Michigan until early Tuesday morning.
When it does, after midnight, it points toward Holland. The 12z
HREF agrees with the NAM and RAP models, both of those showing
surface based, mixed layer and most unstable cape all remaining
below 500 j/kg through midnight. Model soundings show narrow cape
that`s typically located between 5000 and 10000 ft and that`s
about it. Effective shear is forecast to be below 30 knots through
midnight too. So, it would seem while showers are possible and
perhaps even likely tomorrow evening, any threat for strong storms
would be more likely during the day Tuesday.
The more significant threat for our area is tomorrow night and
it`s for heavy rainfall. There is good agreement with just about
all of our high-resolution models for heavy rain (more than 2
inches in 6 hours) from near Holland, through Allegan to
Kalamazoo. This includes the HREF, NAMNEST, FV3, WRF- ARW2 and
Regional Canadian too. The NAM has it after midnight while the
other models have it early in the evening. The 1000/850 moisture
transport from the NAM and RAP do look impressive for heavy
rainfall for Independence Day evening. Having precipitable water
values near 2" along and south of I-94 helps the cause for heavy
rain. Precipitable water values that high are over 2 standard
deviations from normal and near record values for early July (or
any time of the year actually).
- Some threat for convection continues into Tuesday afternoon -
Since the front will be slow to move south, and by mid morning
Tuesday the instability near I-94 is well over 2000 j/kg and the
the effective bulk shear is over 30 knots, it would seem
convection will redevelop in the wake of the earlier or be
triggered by outflow boundary interactions. This threat continues
into the evening.
- Quiet Wednesday then more convection Thursday/Friday
The cold front finally slips south of the state by Wednesday.
That should give us a quiet weather day then. Then the next jet
streak from the Pacific tops the western ridge and comes into our
area in the Thursday / Friday time frame. That will bring warmer
and more humid air once again with the threat of more
thunderstorms. It is possible through that the deepening eastern
trough may become large enough that the convection for Thursday
and Friday may stay south of here. Once that system clears the
area and classic summer weekend looks in store for Southwest
Michigan with little threat for rain, afternoon temperatures in
the 80s and low afternoon humidity.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 808 PM EDT Sun Jul 3 2022
VFR conditions are in place across Lower Michigan at 00Z and this
should remain the case much of the next 24 hours. We will see
some mid and high clouds stream into the area tonight, although
bases will largely be at or above 10,000 feet.
Clouds will begin to lower and thicken from the west late in the
afternoon on Monday and especially into the evening hours. Cloud
bases will remain VFR through 00Z, but we may see some ceilings
around 5,000 feet developing after 21Z. Cannot rule out a few
showers in the west on Monday afternoon and evening and have
included some VCSH wording for now.
Light winds tonight will become south Monday morning after 12z and
increase to 10-20 knots in the afternoon.
&&
.MARINE...
Issued at 329 PM EDT Sun Jul 3 2022
The only real issue this week for our near shore area is
thunderstorms later on Independence day into Tuesday afternoon.
Those may result in large waves and gusty winds. More storms
are possible in the Thursday/Friday time frame.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
DISCUSSION...WDM
AVIATION...Duke
MARINE...WDM
Area Forecast Discussion
National Weather Service Lincoln IL
819 PM CDT Sun Jul 3 2022
.SYNOPSIS...
Issued at 650 PM CDT Sun Jul 3 2022
Mild and dry weather will prevail across central Illinois tonight
with low temperatures dropping into the middle to upper 60s.
Hotter and more humid conditions will develop for the 4th of July
as afternoon highs top out in the lower 90s and heat index values
exceed 100 degrees. Scattered thunderstorms will be possible as
well...particularly along and north of the I-74 corridor.
&&
.UPDATE...
Issued at 819 PM CDT Sun Jul 3 2022
Clear skies are the rule across central Illinois this evening with
01z/8pm temperatures in the upper 70s and lower 80s. Convection is
expected to develop well to the west across Nebraska/Kansas
tonight: however, this activity will have no impact on the local
weather as skies remain mostly clear through the night. Overnight
lows will drop into the middle to upper 60s. Current forecast is
on track and requires no major changes at this time.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 320 PM CDT Sun Jul 3 2022
The center of the surface high influencing central Illinois
weather this afternoon is now over southern Michigan, with a weak
northeasterly pressure gradient leading to east-southeast winds
with a few gusts up around 20 mph. Dew points continue mostly in
the upper 50s to lower 60s with higher moisture values farther
south over southeastern Missouri and southern Illinois. From this
afternoon through tomorrow, at mid levels a 500 mb ridge axis will
maintain a position to the west of Illinois near the eastern
Dakotas/eastern NE.
Difference continue to exist in convective evolution over central
Illinois from CAM forecasts for Monday. In general, expect
increasing convective coverage over KS/NE late this evening,
moving eastward and crossing IA during the early morning hours.
From there, solutions diverge with the majority limiting activity
to the far northern fringes/north of the ILX CWA during the
afternoon on Monday with perhaps some outflow winds moving
southward. However, one or two solutions (including the HRRR)
depict a more linear-like feature moving from west to east through
the CWA during the afternoon and early evening. Around 1000-2000
J/kg of MLCAPE and 20-30 kt of 0-6 km shear will support storm
severity and organization, though the lower-end shear could be a
bit of a limiting factor. SPC slight risk in the northern portion
of the CWA with risk decreasing with southward extent
characterizes the current probabilities well.
Depending on the southward extent of tomorrow`s convection and
outflow, the combination of heat and humidity may be a concern as
well as moist air is pulled back northward/eastward. The current
forecast has heat indices nearing 105 degrees near and south of a
line from Rushville to Olney. A heat advisory has been issued for
our southernmost counties, which will likely need to be expanded
into at least a portion of the forecast area for Tuesday and/or
Wednesday.
.LONG TERM...(Monday night through Sunday)
ISSUED AT 320 PM CDT Sun Jul 3 2022
Forecast concerns for the Monday night through Sunday time frame
center around the following:
1) Extent of and duration of high heat indices through this week,
given the warm/humid air mass south of a frontal boundary and
uncertainties in frontal location/convective evolution
2) Given this week`s pattern and the rainfall deficit in much of
central Illinois, assessing opportunities for rainfall and/or
thunderstorms
It`s hard to separate the above two concerns as they are related.
On Monday night, CAMs in general show initiation of a storm
complex to our north with some uncertainty in whether that complex
moves southward into the ILX forecast area as it weakens on
Tuesday morning, or heads farther east. This could impact 1)
temperatures on Tuesday depending on outflow generated Tuesday
morning and 2) rain chances especially north of I-72/Danville.
Though high temperatures ultimately could be a hair cooler if
rainfall and outflow reach the CWA Tuesday morning, humidity will
be increased as well. At this point, even in this scenario Tuesday
would likely be the day with the highest heat indices of the week.
On Tuesday night, deterministic guidance indicates a setup which
would once again support development of a storm complex to our
north, with another chance of making it into the ILX forecast area
as it weakens Wednesday morning. In addition, the frontal boundary
is forecast to move farther into central Illinois on Wednesday.
The southward movement of that boundary will be one factor in
determining what locations might be in the hot/humid air and still
needing a heat advisory on Wednesday.
The frontal boundary will remain in the vicinity on Thursday and
Friday as shower/thunderstorm chances persist. Temperatures are
forecast to cool somewhat with rain chances decreasing into the
weekend as the ridge strengthens over the central Rockies and the
flow turns more northerly over the Midwest.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 650 PM CDT Sun Jul 3 2022
Main aviation forecast challenge will be potential convective
development on Monday. Short-range models show a variety of
solutions, so overall confidence remains low. General consensus
suggests a cluster or line of thunderstorms will track across
northern Illinois on Monday, with scattered storms developing
further south along an outflow boundary left behind by the main
storm complex. Have followed the 18z HRRR closely for this
forecast...introducing a 3-4 hour window of VCTS beginning at 18z
at KPIA, then at 22z further east at KCMI. Winds will initially be
SE at less than 10kt tonight, then will veer to S and increase to
10-15kt on Monday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 2 PM Monday to 11 PM CDT Wednesday for ILZ040-
047-049>052-061-066-071-072.
&&
$$
UPDATE...Barnes
SYNOPSIS...Barnes
SHORT TERM...AAT
LONG TERM...AAT
AVIATION...Barnes
Area Forecast Discussion
National Weather Service North Platte NE
624 PM CDT Sun Jul 3 2022
.SYNOPSIS...
Issued at 331 PM CDT Sun Jul 3 2022
H5 analysis this morning had high pressure anchored over
the southeastern CONUS. Low pressure was located over northern
Quebec with a second low noted off the coast of Washington State.
Southwesterly flow aloft extended from southern California northeast
into the central and northern Rockies. Zonal flow was noted from the
Dakotas and northern Nebraska east to the Mid-Atlantic. Within the
southwesterly flow aloft, shortwaves were noted over western and
central Montana, along with a decent shortwave over southern
Colorado. Stilt imagery from late morning indicated a weak meso-
vort over west central Kansas. Northeast of this feature, a shield
of stratus was present over central into eastern Nebraska. Dew
points in this area of stratus were generally around 70 degrees as
of 11 AM CT. Shifting to this afternoon, the stratus field had
shrunk to eastern Nebraska. Southerly winds and hot temperatures had
replaced this feature with readings ranging from around 90 degrees in
northern Nebraska, to the upper 90s in southwestern Nebraska.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 331 PM CDT Sun Jul 3 2022
The main forecast challenges in the near term are thunderstorm
chances tonight and Monday night along with the heat on
Independence Day. For tonight, the latest CAMS and Nam soln
develop some convection this evening across the forecast area.
With this morning`s runs, there are two schools of thought when
comparing the NAM soln to the HRRR solns this morning. The NAM12
and NAMNest solns develop two rounds of convection. The first is
over southwestern Nebraska INVOF the differential heating boundary
which was a result of the eroding stratus field from earlier
today in South Central and Central Nebraska. The second is in the
form of a line which develops later this evening and conjeal`s
into a mcv across central into northern Nebraska overnight. With
the second mode, we already have some convection beginning to form
over eastern Wyoming ATTM so this seems plausible and feel fairly
confident in this carrying east into our forecast area later this
evening. With respect to convection developing over SW Nebraska,
this is more up in the air, however, with some agitated CU
development around MCK over the past hour, this seems plausible as
well. With this in mind, will paint pops early on in the SW and
west, then carry this eastward into the overnight hours. As for
severe mode, hail is a threat in SW Nebraska early on, as mid
level CAPE`s reach 1500+J/KG through early evening. Very large
hail however doesn`t seem like a threat ATTM given the weak mid
level winds H500-H700 and marginal 30 KTS of deep layer shear. The
severe mode transitions more to a wind threat later this evening
as a robust 35 to 50 KT low level jet develops from south central
into central Nebraska. With the expected development tracking east
into central and north central Nebraska later this evening, any
storms which can become anchored on the jet have a decent chance
to produce some gusty winds. On Monday, a weak frontal boundary
will sag south into far northwestern Nebraska. South of the front,
temps will reach well into the mid to upper 90s, with some
readings reaching around 100 degrees in SWrn into central
Nebraska. With dew points in the lower to middle 60s Monday
afternoon, resultant heat indexes will reach 100 to 105 degrees
generally along and east of a line from Valentine to North Platte
to Hayes Center. That being said, decided to hoist a heat advisory
for these areas from 1 PM To 8 PM CT Monday. There will be a more
limited threat for thunderstorms Monday afternoon into Monday
evening across the area. With the front expected to be draped over
the northwestern forecast area Monday afternoon, there is a
surface focus for convective development. However, SB CAPES are
very meager Monday afternoon. In fact the best CAPE is north of
the forecast area over southern South Dakota. However, with the
expected surface boundary in place, went ahead and included some
low pops across the northern half of the forecast area Monday
evening.
.LONG TERM...(Tuesday through Sunday)
Issued at 331 PM CDT Sun Jul 3 2022
The before mentioned front will stall across the forecast area
Tuesday. South of this feature, heat indexes will once again top
100 degrees. This will ultimately lead to the need for a heat
advisory somewhere in the southern forecast area. There is still
some doubt as to where this front will reside given the expected
convection today and possible convection Monday afternoon. That
being said, decided to hold off on issuing a heat headline for
Tuesday afternoon. As for the threat for storms, it appears better
on Tuesday afternoon/evening. Available CAPE is much better on
Tuesday afternoon with SB CAPES of 2000-4000 J/KG across the area.
Deep layer shear is more robust as well on the order of 30- 40
KTS which will be more favorable for severe storms compared to
Monday`s setup. The threat for afternoon and evening thunderstorms
will continue Wednesday and Thursday as the persistent trough
remains off the coast of the Pacific NW states. This feature will
lift into western Canada late in the week, allowing the ridge
across the SE CONUS to build northwest into the southern and
central Plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 624 PM CDT Sun Jul 3 2022
Scattered thunderstorms are expected throughout wrn and ncntl
Nebraska this evening through 09z Monday morning. No thunderstorms
are expected thereafter through Monday afternoon.
There is a chance, about 30 percent, sporadic MVFR ceilings will
develop Monday morning, generally affecting areas along and east
of highway 61 and south of highway 20 between 09z and 15z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM CDT /noon MDT/ to 8 PM CDT /7 PM MDT/
Monday for NEZ005>010-025>029-037-038-059-070-071.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...CDC
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
753 PM CDT Sun Jul 3 2022
.UPDATE...
Issued at 753 PM CDT Sun Jul 3 2022
It`s a beautiful evening with light winds, mostly sunny skies.
and temperatures in the lower 80s.
National satellite imagery depicts numerous areas of convection
stretching from western Montana to southern New Mexico, the
Dakotas, Southern Plains, Ozarks, and mid-Atlantic. The Great
Lakes and northeastern United States are just about the only parts
of the country east of the Rocky Mountains enjoying a pleasant,
storm-free evening. Our luck appears to be running out however, as
chances for storms look to increase tomorrow and last through the
end of the week.
It`s tough to add more value to the going forecast for tomorrow
given the convection upon which it is reliant is only now becoming
organized well to our west. It remains probable that some remnant
form of thunderstorms or a convectively-invigorated upper-level
shortwave trough from overnight will track into the western Great
Lakes tomorrow afternoon and present a chance for at least
scattered thunderstorms across our area. We remain (cautiously)
optimistic there will be a break before additional, likely more
vigorous, thunderstorms develop after dark and parade through the
night. In these scenarios, it`s tough to pinpoint where new
thunderstorms will develop given a dependence on so many factors
in the 12-24 hours beforehand. Recent high resolution guidance
offers placements ranging from southern Wisconsin to southern
Lower Michigan northeastern Illinois. We anticipate spread to
remain in the upcoming suite of 00Z guidance. At any rate,
wherever the 2nd round develops, severe weather and flash flooding
threats will no doubt make their presence known given
increasingly "fat" CAPE profiles and PWATs climbing (well?) above
2 inches.
For now, we`ll enjoy our last quiet evening for a while in
anticipation of our upcoming stormy stretch.
Borchardt
&&
.SHORT TERM...
Issued at 152 PM CDT Sun Jul 3 2022
Through Tonight...
A rather extensive cu field has developed on the lake breeze this
afternoon, with sunny skies near the lake. Some of the short term/
high res guidance has been occasionally developing a shower on
the lake breeze through mid/late afternoon. Confidence is very low
but an isolated shower or some sprinkles are possible through
late afternoon, with the lake breeze, across northeast IL. This
cloud cover will dissipate early this evening with increasing
high/mid level cloud cover overnight into the predawn hours. Low
temps will drop into the lower/mid 60s for most of the area, with
upper 60s/lower 70s for the immediate Chicago metro area. cms
&&
.LONG TERM...
Issued at 259 PM CDT Sun Jul 3 2022
Monday through Sunday...
This Independence Day will feature unsettled weather in the
region with a hot and humid air mass impinging and the likelihood
of some thunderstorms. The character and timing of these
thunderstorms for the last few days has been of lower confidence,
though certainty on how this will pan out is starting to inch
higher for the daytime and early evening, before confidence drops
into the night through Tuesday.
Key messages are:
* Increasingly more humid by the 4th of July evening, then hot
and humid Tuesday
* A swath of scattered showers and storms moving east over the
area during the afternoon of the 4th; fairly low severe chances
(level 1 of 5) with this
* Potential for organized thunderstorms to develop over/near
southern Wisconsin in the evening and track southeastward into
the area; low confidence on the size, timing, and track of such
a complex but some severe threat with this (level 2 of 5)
* Heavy rain and some flood threat with late evening and overnight
activity especially if it were to materialize and backbuild
The broad and still somewhat flat upper ridge will have expanded
across the nation`s midsection to start the 4th. The mid level
short wave of interest for afternoon activity is backtracked in
model solutions to eastern Colorado at present, and while nothing
stands out on current satellite water vapor imagery, guidance of
various resolutions is in solid agreement of this. This feature
and an associated 40 kt 700 mb speed max will ride atop the ridge
while possibly having convective enhancement over Iowa early on
the 4th, before tracking eastward into/near northern Illinois
during the afternoon. This will at the leading edge of broader
warm advection aloft and a sharp gradient of tropospheric
moisture (PWATs) and instability (MUCAPE). All of this supports an
area of scattered showers and some convection, though how compact
this is is tough to decipher. But there should be a 3-4 hour
window of increased shower and some thunderstorm chances, probably
greater north of I-80 given the vort track. Instability and even
shear are expected to gradually increase, so some stronger storms
may evolve after 4 PM from west to east, especially if this wave
is more convectively-enhanced with greater shear.
The expected cloud cover during the afternoon (also thicker
north of I-80), should retard temperatures from warming too
significantly. Those locations seeing rain will likely drop
several degrees too. South of I-80 and maybe into Chicago has the
best chance of hitting 90 early in the afternoon before any
slight cooling. Dew points will be rising through the 60s and to
70 by late afternoon, and this is well agreed upon in guidance.
While the above is the part of the forecast where confidence has
increased the most, in the evening time of many outdoor
festivities the confidence remains on the lower side.
Conceptually a drop in coverage behind the mid-late afternoon
activity would be expected in such a setup, however there is not a
strong cap building in and there is the likelihood of an
additional short wave further north tracking across the Upper
Midwest. This will have the likelihood of interacting with the
surface warm/stationary front where more heating had occurred near
the border region of Minnesota-Wisconsin-Iowa for convective
initiation in the early evening. This idea at least has the
backing of a large majority of both global and high-resolution /
convection allowing models (although the HRRR shows little
development in the area). So have leaned the forecast a little
more in this direction, with PoPs increasing in the north in the
early-mid evening, and then quickly increasing late evening into
overnight from north to south. This timing will be close to
impacting outdoor evening festivities, especially in the northern
CWA, though given the air mass that will have expanded into the
area, nowhere is free of evening thunder chances.
Regarding storms during the late evening into overnight, the
instability/moisture/shear spectrum space upstream would support
potentially rapid growth and upscale organization. The low-level
jet is forecast at 45 kt and unimpeded into southern Wisconsin,
so that conceptually supports the idea of good moisture
replenishment as well as potentially a zone of regenerating and
backbuilding convection on the western/ southwestern portion of
any MCS. The 12Z HREF mean of its members depicts 1.5-2 inches of
rain for along/north of I-90, and that`s a decent heavy rain
signal for >24 hours out. The forward propagation MCS area (if
one does develop) would be on the eastern/southeastern side would
have the chance for at least embedded severe winds. This does not
scream a rapidly propogating feature, but most models do show deep
layer shear greater than 30 kt north of I-80 and ample features
for cold pool organization with deep cores on the leading edge.
For Tuesday, much may be impacted by what occurs Monday night, as
it typical with the "domino effect" of being on the northern
periphery of a heat dome. Synoptically, there`s support for
building heights during the first half of Tuesday, which would
likely minimize convection, however the front/outflow composite
will be either in or near the CWA, with signatures of a backdoor
push off the lake. A lack of capping with this setup would
support afternoon convection along the wind convergent areas.
Signs of short wave energy passing over the Corn Belt region
increase late Tuesday into Tuesday night. Overall, not enough to
change much from "chance of showers and thunderstorms" at this
point. Mixed-layer CAPE looks to be above 2,500 J/kg and non-
weak (25-35 kt) mid-level flow would support scattered severe
potential, if convection can fire.
Tuesday temperatures will also have some modulation from any
convection or convective effects, including from late Monday
night. But either way it looks hot and humid. Flow does look to
turn off the lake for the Chicago metro and far northwest Indiana,
but that may not happen until later in the afternoon. With dew
points solidly in the 70s, heat index readings well away from the
lake very well could top 105F and require a Heat Advisory.
MTF
[Wednesday through Sunday]
Wednesday and beyond, there does look to be potentially several
more convectively enhanced vort traversing the general region.
Timing and placement details of these features will have huge
impacts on precip chances and amounts as well as temperatures as
MCS activity will undoubtedly play a big role in the location of
the effective boundary. Near and south of the boundary, air mass
will be very humid and hot, with heat indices over 100F a good
bet. That boundary could easily lift north into or even north of
our CWA at times, bringing heat and humidity to the region.
It`s not uncommon for the effective boundary ends up being
farther south than some of the model guidance suggests in active
ring of fire regimes as convective cold pools shove the effective
boundary southward.
Given the high degree of uncertainty in the forecast, saw no
reason to stray from NBM through the period. There very well could
be two or three bouts of heavy rainfall and/or severe weather,
but an examination of the individual GEFS and EPS (ECMWF) ensemble
members still shows a plausible scenario that there very well
could be areas that end up with not much additional precip. This
being said, noted on the 12z cycle a stronger signal for a much
more active Friday-Friday evening than some of the previous runs.
All in all, it`s all going to be a matter of where these convective
clusters/complexes track and if your particular garden, lawn, or
crops end up on the receiving end of the precip or end up being
one of the potential have-nots. Also important to note that while
the forecast will show precip chances every day and night through
the upcoming week, there will be extended periods of time with no
precip and that the week will not be a total wash out.
By the weekend, some amplification of troughing east and northeast
of the Great Lakes and further amplification of the intense heat
ridge out west (ie. 600 DM at 500 mb over the Rockies on the 12z
ECMWF) could/should allow Canadian high pressure to build south
resulting in less humid air and far lower precip chances by
Saturday and Sunday. Temperatures will be seasonably warm inland
and cooler lakeside due to persistent onshore winds.
Castro/Izzi
&&
.AVIATION...
For the 00Z TAFs...
Aviation Forecast Concerns:
* A couple of rounds of organized thunderstorms are possible
later in the forecast period. The first Monday afternoon, and
then another later Monday evening/overnight.
In the near term, all is quiet across the forecast area with fine
VFR aviation weather this evening. Surface high pressure was
centered across the northern and central Great Lakes providing
generally light southeast winds across the region. Slightly
stronger and more easterly wind component associated with lake
breezes off of Lake Michigan will diminish quickly this evening.
Winds turn southerly Monday morning with some potential for gusts
into the 15-20 kt range during the day, though thickening high
cloud cover may temper gusts a bit. Of greater concern will be an
area of showers and thunderstorms which is expected to move into
the area from the west during the early-mid afternoon hours in
association with a warm front, and a mid-level disturbance
currently emerging from the central Rockies. Various CAM guidance
is in relatively decent agreement in depicting storms moving into
the KRFD area 19-20Z, and into the Chicago metro terminals in the
20-22Z time frame. These should propagate east of Chicago around
00Z, though a more humid and unstable air mass spreads in behind
these heading into Monday night. A strengthening low level jet is
expected to regenerate thunderstorms across parts of eastern
IA/WI/LM along/north of the surface warm front which lifts across
the area in the afternoon. Several CAMs (3km NAM, NSSL WRF, RAP,
FV3) indicate storms develop northwest of the area across parts of
southern WI early Monday evening, then spreading southeast across
northern IL and the terminals during the late evening/early
overnight hours. While some timing differences exist, did include
a prob30 from 04-06Z for ORD and MDW to show the trend into the
overnight particularly with the potential for these storms to be
strong to severe.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion...UPDATED
National Weather Service Portland OR
900 PM PDT Sun Jul 3 2022
.SYNOPSIS...A weak upper level trough over the region will
maintain near to slightly below average temperatures for much of
this week with morning clouds followed by afternoon sunshine
each day. Chances for showers continue through at least
Wednesday.
&&
.SHORT TERM /THROUGH TUESDAY/...Cool low levels beneath a cold
core upper low off the coast coupled with warmth east of the
Cascades is driving the weak onshore flow. A similar trend of
strong onshore flow aloft is expected tonight which likely will
bring a return of the marine stratus...although possibly not
nearly as deep as what occurred last night. Forecast soundings
from the NAM and HRRR suggest that winds beneath roughly 5000 ft
(850 mb) will become virtually absent tonight, and that the
boundary layer will be saturated from the surface up only to
around a half kilometer. So with its lack of depth will lead to
less cloud cover and minimal (if any) drizzle relative to what
the area experienced this morning. The best chance for it will
be along the north Oregon coast, where a slight chance was added
to the forecast.
Aside from those few showers (which are most likely in the
south Valley and Cascades) early in the morning, Monday will be
dry until the late afternoon when scattered showers are expected
to move north-northeast into the area from southern Oregon
ahead of another lobe of upper level low pressure rotating into
the PacNW. Forecast soundings continue to advertise a stable
layer around 500-600 mb, so thunderstorms Monday evening/night
continue to appear unlikely for any part of the CWA. Another
round of showers will be likely on Tuesday, with the
overwhelming majority of members within the EPS depicting QPF in
our area. There are once again some hints that instability may
be sufficient for thunder in the Lane and Linn County Cascades
Tuesday. Both NBM and SREF suggesting 20+% probabilities for
thunder along and near the crest, and forecast soundings from
the NAM again suggesting more than 500 J/kg of MUCAPE. It
appears that flow within the unstable layer below roughly 500 mb
will have a large enough westerly component that cells will be
driven quickly east of the crest, but before that time a strike
or two seems reasonable. Thus, a slight (i.e., 20%) chance for
thunder has been added to the forecast for those areas; this
means that lightning is possible with convection, though chances
for not hearing thunder are 4 times greater. -Muessle/Bumgardner
.LONG TERM.../WEDNESDAY THROUGH SATURDAY/...WPC`s cluster
analysis page forecasts generally less than a 75 dam difference
in 500 hPa height between the coolest and warmest clusters
throughout the extended, indicating ensemble agreement in the
medium range is high. Through at least Thursday, the upper low
dominating our weather in the short term is most likely to
remain just west of us over the eastern Pacific, maintaining
near to slightly cooler-than-normal temperatures and transient
but frequent chances for precipitation amidst south-
southwesterly mid level flow.
NBM has maintained its chances for thunderstorms in the Cascades for
Wednesday and Thursday, and forecast soundings display some
instability supportive of this potential. Thus, no major changes
have been made to the forecast for areas with slight chance mentions
for thunder. Wednesday continues to look like the day with the most
expansive thunder threat throughout the Cascades as it is the day
with the least westerly component to the low and mid level flow (and
hence storms that develop in the high terrain will not be quickly
driven east of our area, but will rather ride northward along the
mountains).
Uncertainty in whether the low dissipates and the PacNW is overtaken
by the ridge to our east becomes apparent next weekend, when the
temperature and precipitation forecasts become a little less clear.
Currently the NBM`s prediction for both was not touched during that
time period, when chances for precipitation appear highest in the
Cascades, and temperatures are forecast to climb into the mid 70s to
low 80s in the Willamette Valley - near to just below climatology.
-Bumgardner
&&
.AVIATION...06Z TAFs: An upper low pressure near the Oregon coast
will drift northeast tonight and into Washington on Monday. Will
see variable mid to high clouds passing across the area with a
chance of lower marine stratus overnight. Latest model guidance
suggests onshore flow weakens tonight before strengthening again
by Monday afternoon. Model guidance has also backed off on
widespread MVFR developing again overnight, but will keep a
mention of a few hours of possible MVFR conditions between 10-14Z
Monday, although cigs will most likely be around 3500-5000 feet.
One exception may be near the north Oregon coast, where more
frequent MVFR expected at KAST. Skies should then scatter out
by afternoon with predominately VFR conditions expected.
For detailed Pac NW aviation weather information, go online to:
https://weather.gov/zse
KPDX AND APPROACHES...Predominately VFR expected tonight and
Monday. Will see mid level clouds move north across the region
while lower marine stratus attempt to redevelop around 12-16Z
Monday. May experience brief MVFR but cigs most likely around
4000-5000 feet. Light northwest wind through the period. -DH
&&
.MARINE...
Weak surface high pressure remains over the coastal
waters, while upper low pressure remains off the west central
Oregon coast. Pressure gradients not all that strong, keeping
winds 5 to 15 kt into Tue. Seas not all that much, running 2 to 4
ft. But, will have a mix of swell fetches over next few days.
Primary swell is west swell 2 to 3 ft at 10 seconds, with a
secondary swell running 1 to 2 ft at 15 seconds. -Rockey
For information about upcoming marine zone changes, go online to:
https://www.weather.gov/pqr/marinezone
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.
&&
$$
www.weather.gov/portland
Interact with us via social media:
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Area Forecast Discussion
National Weather Service Pueblo CO
324 PM MDT Sun Jul 3 2022
.SHORT TERM...(This evening through Monday)
Issued at 320 PM MDT Sun Jul 3 2022
Key messages:
1. Scattered to numerous thunderstorms expected into this evening,
main risks will be lightning and locally heavy rainfall.
2. No change in the weather pattern for Monday, with widespread
afternoon/evening storms over the mountains, scattered to
isolated coverage elsewhere.
Another round of afternoon/evening convection across the area today,
though storms look a little weaker than yesterday, perhaps due to
lee surface trough on the plains and subsequent wly downslope flow
along the I-25 corridor behind it. Low shear (0-6km values of 20 kts
or less) also playing a role in keeping storms relatively weak,
though one or two cells could become strong/low end severe in the
more unstable air and better wind regime east of the lee trough on
the plains and along the Palmer Divide. Again expect main risk with
convection into the evening will be locally heavy rainfall,
especially with some training/redevelopment along weak boundary from
Trinidad to La Junta. Expect most activity to fade away toward
sunset, though latest HRRR does drag some convection off the
mountains into the Interstate 25 corridor 9-11 pm. May also see
some showers linger back over the southwest mountains into Monday
morning, as deeper moisture lingers through the night.
On Monday, not seeing much change to the upper level or surface
pattern across the area, with continued feed of mid-level moisture
in place while weak lee surface trough hangs out over the eastern
plains. Expect convective coverage/strength to be similar to Sunday,
with highest pops over the mountains, and least chance for storms
over the far ern plains near the KS border. Little change in
precipitable water, so again locally heavy rainfall the main storm
threat. Max temps will continue a very slow upward climb over the
plains, while mountains/valleys see little change.
.LONG TERM...(Monday night through Sunday)
Issued at 320 PM MDT Sun Jul 3 2022
Key messages:
1) Fourth of July evening, scattered PM thunderstorms for several
locations may create another light show other than only fireworks
for some. A few stronger storms could produce flash flooding in
urbanized areas and over burn scars.
2) Widely scattered PM thunderstorms will be possible over the most
areas from Tuesday through Thursday. PM storms will be more isolated
for Friday through Sunday and mainly over mountains. Flash
flooding will be possible, especially over burn scars and urban
areas.
3) Temperatures will be warm on Tuesday, with a slight cooling trend
Wednesday through Thursday, then becoming much warmer Friday through
next weekend.
Detailed discussion:
Fourth of July evening...
Latest HRRR shows a majority of the late evening thunderstorm
activity on Monday being mainly over the I-25 corridor. The NAM 4km
Nest keeps most of the convection confined more to the central
portions of the I-25 corridor and along US-50 and just south.
Analyzing the NAM12 lapse rates, steeper lapse rates appear to be
over the Palmer Divide and the Raton Mesa. The model also shows a
very high concentrated area of CAPE over the southern Sangre de
Cristo Mountains of over 2000 J/kg in some areas. Given relatively
higher shear of nearly 30kts as opposed to the surrounding areas,
there could be a possible stronger or severe thunderstorm form just
after 6 PM over this area and move out over the adjacent plains,
possibly impacting locations such as Trinidad and Aguilar just
before sunset, or right around the time for firework viewing. Some
of the thunderstorms over the northern areas of the Sangre de Cristo
Mountains, as well as the Wet Mountains, could also impact portions
of the I-25 Corridor in Huerfano and Pueblo Counties. The Palmer
Divide area looks like it could also be dealing with a thunderstorm
right around sunset that will be moving into Lincoln County. Given
the better shear and steeper lapse rates in this area, it is
possible that a storm could become severe. However, soundings around
this time for Colorado Springs reflect high LCLs with an inverted V
signature, so the main threat would be gusty outflow winds to
possibly 60 mph. With elevated cores above -20C, some hail will be
possible, although CAPE appears to be only around 600-700 J/kg over
most of El Paso County, so hail will likely not get bigger that pea
size. The better potential of severe storms will exist further south
over the southern Sangre de Cristo Mountains, where torrential rain
could bring about flash flooding, especially over the burn scars.
Hail potential will also be a bigger threat in this area, with
possibly nickel size (or greater if storms become severe). As these
storms move over into the adjacent plains and the southern I-25
corridor, there could be localized flash flooding in the urbanized
areas. Storms could move out into the central and eastern plains,
but should continue to weaken by midnight. Low temperatures for
Monday night will be generally in the 60s for the plains, to the 40s
and 50s for higher country.
Tuesday through Thursday...
Ensembles and deterministic models have been consistent for the past
several days with the long wave pattern during this period in the
forecast, showing troughing over the northwestern CONUS remaining
nearly stationary and keeping the ridge over central CONUS. As the
ridge overhead begins to flatten slightly, along with weak
perturbations moving through in the longwave troughing upstream, the
monsoonal moisture plume will shift back to being more over
southeast Colorado, which will provide more widely scattered to
numerous PM thunderstorms to develop over most areas of the CWA for
Tuesday through Thursday. Tuesday will be quite warm, especially
over the plains, under a stronger ridge. As troughing upstream helps
to weaken the ridge and also allow for more moisture to move in over
the region, there will be a slight cooldown from Wednesday through
Thursday. With the enhancement of mid-level moisture over the
mountains coupled with weak shear, there will continue to the the
threat of storms remaining nearly stationary. This could result in
potential flash flooding, especially over burn scar areas, for all 3
days during the afternoon and evening hours.
Friday through Sunday...
By Friday, as the ridge begins to build back again over the region
and the upper level high over western Texas begins to slightly
retrograde further back to the west, the moisture plume will also
shift back to the west with a more north to south orientation of the
ridge axis and keep any thunderstorm initiation confined to the
mountains with a more northward mid-level flow. There will continue
to be possible flash flooding concerns over the burn scars due to
weaker mid level shear. Saturday will be very similar, with a
slighter chance of thunderstorms over the plains and storms being
more isolated over the mountains and confined mostly to the central
mountains. Temperatures on Friday and Saturday will also be much
warmer under the strengthening ridge with near 600 dm heights
centered over western Colorado showing up on the ECMWF at the 500mb
level on Friday. The GFS is now in better agreement with the ECMWF
when it comes to the 500 mb heights being closer to 600 dm. The
models tend to differ much more going into the weekend, with the
ECMWF showing the ridge strengthening over the region and forcing an
upper level low to become cut-off over northwest CONUS, whereas the
GFS has the ridge flattening and troughing upstream beginning to
push over the area on Sunday. If the ECMWF resolves this better, the
monsoonal plume will remain more confined to the mountains with much
drier and warmer temperatures for the plains. If the GFS resolves
this better, the plume will be forced back to the southeast and
allow for a better chance of thunderstorms over the plains with
cooler temperatures overall. -Stewey
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 320 PM MDT Sun Jul 3 2022
VCTS risk at all terminals until 02z, with best chance of storms at
KCOS and KALS. Wind and heavy rain/low visibility will be the main
risk with storms, though some pea size hail is possible with the
stronger storms. Activity ends 02z-04z, though a vcsh may linger
through the night at KALS, as plentiful moisture remains over the
area. Little change in the pattern Monday, with afternoon/evening
convection once again after 20z-22z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...STEWARD
AVIATION...PETERSEN
...Update to aviation forecast discussion...
.DISCUSSION...
Issued at 235 PM CDT Sun Jul 3 2022
19Z water vapor imagery shows broad mid level ridging over the
southern plains and lower MS river valley while mid level
troughing and a closed low affects the Pacific Northwest. This
ridge over the southern plains is not pristine as an obvious vort
max was noted over north TX where showers and storms have formed.
But it is hard to see an obvious shortwave over the central high
plains as the models have progged. At the surface, troughing along
the lee of the Rockies has allowed a little more southerly wind
to develop over the area and dewpoints have risen into the lower
and middle 70s as a result.
Hot weather continues to be in the main focus of the forecast
beginning Monday and lasting at least through mid week. Across
northeast and east central KS, the NBM shows little spread in the
max and dewpoint temperatures leading to good confidence in the
forecast heat indices. There is a little more uncertainty for parts
of north central KS where dewpoint temps could mix out a little
more. But the actual temperature is likely to remain close to the
century mark. In addition to the afternoon temps, overnight lows do
not look to provide much relief from the heat with min temps
expected to only fall into the mid and upper 70s for a few hours. So
with good confidence in the forecast during the first part of the
week, have gone ahead and issued a heat advisory for much of the
area beginning Monday afternoon through Wednesday evening. The NBM
shows increasing uncertainty in temps after Wednesday so
confidence is not high enough to consider an advisory beyond
Wednesday. Nevertheless the forecast keeps the heat and humidity
around through the end of the week and if confidence in the
forecast increases, the advisory may need to be upgraded to a
warning for parts of the area that see four or more days of
advisory level heat.
As for POPs, models continue to show what now looks like a
convectively generate vort max lifting through southern NEB
overnight. The GFS and RAP have trended further south with their QPF
progs as inhibition increases tonight south of the state line. Am
not sure I buy into this since mid level flow would tend to keep
the vorticity north of the forecast area. So have kept some low
end chance POPs across the far northern counties tonight in case
convection builds south. Deep layer shear is very marginal across
the forecast area tonight so it is uncertainty whether there could
be severe storms. The main concern would be if an MCS develops
and is capable of producing wind damage with a sustained cold
pool.
Have kept a dry forecast going for Monday, but the mid level
vorticity over north TX is progged to move into northeast KS Monday
afternoon and begin shearing out. 700MB level temps warm to about
13C with no obvious low level feature to focus convergence. With
models including the CAMs failing to generate any precip through the
afternoon, think chances are less than 20 percent but that is not to
say something couldn`t pop up in the heat of the day.
There are chance POPs in the forecast Tuesday night through Friday
as models continue to suggest a weak boundary moving in from the
west. It continues to look like Thursday or Friday stand the
better chances as shortwave troughing weaken the mid level ridge.
Unfortunately by the weekend models have the ridge redeveloping to
the west of the forecast area. This is likely to keep the
forecast dry with no relief from the heat and highs remaining in
the mid and upper 90s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 606 PM CDT Sun Jul 3 2022
Short term concern is propagation of current convection to the
south of TOP/FOE. Outflow is causing new storms to develop
northward and this trend will continue through sunset so will
include vicinity thunder in the forecast given it is uncertain how
close this convection will get to TOP. Meanwhile, developing
thunderstorms across central KS will move ENE and should stay
northwest of the MHK site through 5z but needs to be monitored.
LLWS may develop after 5z through sunrise around 2000ft.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon Monday to 9 PM CDT Wednesday for KSZ011-
012-021>024-026-034>040-054>056-058-059.
Heat Advisory from noon Monday to 9 PM CDT Tuesday for
KSZ008>010-020.
&&
$$
DISCUSSION...Wolters
AVIATION...Omitt
Area Forecast Discussion
National Weather Service Tucson AZ
200 PM MST Sun Jul 3 2022
.SYNOPSIS...Scattered showers and thunderstorms are expected through
this evening and again on the 4th of July. Then Tuesday through
Friday the storms should become more isolated and mainly limited to
areas near the Mexico and New Mexico borders with afternoon
temperatures gradually warming. Storm activity should gradually
increase again next weekend.
&&
.DISCUSSION...Storms started developing pretty much on cue late this
morning and the HRRR seems to be doing well with the initial
convection development. If that accuracy holds than the Tucson metro
has a chance of a some showers/storms rolling through later today.
For the 4th of July, we should have a little wave in the flow roll
northward through the area although it may be a bit earlier than
ideal if your looking for maximum affect. Multiple model solutions
continue to suggest an upswing in activity tomorrow afternoon and
evening and a little further west than today which makes sense given
the scenario. Several of the CAM solutions indicate a group of storms
rolling SE to NW through the Tucson metro later in the day tomorrow
for more naturally generated fireworks. We will see!
For Tuesday through Thursday and potentially Friday, we will see a
gradual decrease in storm amount/coverage as the upper trough to the
west lifts up and the upper level high begins trying to consolidate
toward the west. This won`t be a shut down but storms will be fewer
and primarily affecting far eastern and southern areas. With this
kind of transition, afternoon temperatures will be on a gradual rise
and at this time appear to peak Saturday around 3 degrees warmer than
average. Ensemble/blend guidance then points to more moisture
gradually returning to the area with temperatures slowly settling
back. That said there is a fair amount of difference in various
operational runs so the transition may not be as smooth as it looks
at this time.
&&
.AVIATION...Valid through 05/00Z.
Through 04/05Z, SCT-BKN clouds at 7k-9k ft AGL and SCT SHRA/TSRA
from a KTUS/KOLS line eastward. Slowly diminishing clouds and
shower/storm activity aft 04/05Z. Erratic SFC wind gusts and outflows
in excess of 40 kts possible with TSRA during the afternoon and
evening hours. Somewhat more widespread showers and Thunderstorms
expected Monday afternoon and evening. Otherwise, SFC wind generally
less than 12 kts, favoring a SLY/SWLY direction during the afternoon
hours and variable in direction at other times. Aviation discussion
not updated for TAF amendments.
&&
.FIRE WEATHER...Scattered showers and thunderstorms into this evening
mainly from a Tucson to Nogales line eastward. Monday we should have
a bit more storm coverage which should also expand to just west of a
Tucson to Nogales line. Storm chances diminish Tuesday into Friday
and become more confined to the New Mexico and Mexico border areas.
Then starting next weekend, storm coverage should be on the increase
again as the upper level high tries to settle into a more typical
monsoon patter, 4-corners area.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
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Fire Weather....Cerniglia
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