Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/03/20
Area Forecast Discussion
National Weather Service Bismarck ND
938 PM CDT Thu Jul 2 2020
.UPDATE...
Issued at 930 PM CDT Thu Jul 2 2020
Updated to remove severe watch WW324. An isolated strong to very
low end severe storm will be possible for the next hour or two
along the line of convection, but the overall trend is lowering
intensity. Bismarck just had a wind gust to 49 knots in the wake
of convection.
UPDATE Issued at 910 PM CDT Thu Jul 2 2020
Passing on that if current trends continue in storm intensity
decreasing we will be dropping the rest of severe watch WW324 for
the rest of North Dakota. To do this, if warranted, before the 10
PM newscast would be an excellent service.
UPDATE Issued at 839 PM CDT Thu Jul 2 2020
Update to remove the western half of severe watch WW324.
Storms are being kicked east by the impending H5 wave and entering
a less favorable environment for severe. Hail risk, with the line
of storms, has become less of a concern now than gusty winds.
UPDATE Issued at 755 PM CDT Thu Jul 2 2020
Strong to severe thunderstorms continue to propagate northeast
through central North Dakota as of this writing. Convection
initiated in an area of moisture pooling along a surface boundary
through western North Dakota. That boundary was pushing slowly
east.
An H5 wave pushing in from the west has been the kick to gets
storms moving as initially they were very slow moving. Question
becomes how much longer can convection sustain itself before it
outruns the favorable shear and increasing inhibition as evening
sets in. Along the U.S. Highway 83 corridor MLCape is running
2000-2500J/KG while the latest RAP analysis shows CIN increasing.
Just a few hours ago the effective shear had shown a marked
increase into the central part of the state, and now that was
shifting back to the west again. With that said, will expect the
overall intensity of convection to weaken over the next few
hours, but not completely dissipate, with isolated severe storms
still possible at least until 10 PM CDT over the watch area.
Have removed Slope, Bowman and Adams counties from the watch as
storms have moved out of there and the risk of severe weather
there has significantly decreased.
UPDATE Issued at 535 PM CDT Thu Jul 2 2020
Forecast updated for new WW324 severe thunderstorm for most of
central and into southwest North Dakota. Storms have broken loose
on the west edge of the CAP near the surface boundary and were
clustering toward the northeast. Will expect storms to continue to
fire toward the east with the western North Dakota surface
boundary as it inches east.
&&
.SHORT TERM...(This evening through Friday)
Issued at 327 PM CDT Thu Jul 2 2020
The main concern for the short term period is chances for severe
thunderstorms.
Closed upper low continues to spin over central Alberta with a
positively tilted ridge axis from the Great Lakes to Texas. A pre-
frontal surface trough is analyzed from near Mohall to Buffalo, SD,
and is a bit farther west than previously expected. Convection
initiation appears to be underway along/just ahead of the surface
trough in southwest North Dakota where SBCIN is eroding. SPC
mesoanalysis places up to 5000 J/kg SBCAPE and around 40 kts
effective bulk shear over the area. Initial storms should remain
discrete. Upscale growth into clusters/linear segments is possible,
but not a certainty due to weaker mid/upper level forcing, and right-
moving Bunkers vectors would likely move discrete supercells away
from the surface boundary. The main hazard is expected to be very
large hail, with damaging winds also possible. The tornado threat is
marginal at best, mainly due to relatively high LCLs, but still
greater than zero. It is unclear how far north and east the threat
for severe weather may expand, mainly due to capping concerns.
Further to the east, sub-severe convection has been percolating over
central North Dakota along a corridor of strong low level southerly
flow. Much greater CIN and weaker shear will likely keep this
activity below severe limits.
There is potential for the development of additional convection
overnight from southwest into central North Dakota on the nose of a
low level jet and associated low to mid level moisture transport.
Forcing may be aided by mid level shortwave energy. This potential
is likely highly contingent on the latitudinal placement of the
LLJ/moisture transport, which may be influenced by remnant outflow
boundaries from convection this afternoon and evening. MLCIN will
obviously be present at this time of day. But interestingly, the RAP
does show a weakening trend in the cap after midnight CDT. If air
parcels are able to break through the EML, MUCAPE and effective bulk
shear would promote a severe threat, which may continue into Friday
morning.
Details on timing and location of convection Friday and Friday night
remain murky at best. There is general agreement for active
southwest flow aloft topping a Central Plains ridge, with strong
moisture advection in low level southerly flow. The trend in CAMs
has been for mostly dry weather during the afternoon, while some
global models suggest meandering MCSs through the day. The potential
for early morning convection further complicates the picture and
decreases predictability. However, the environment over this time
period will generally contain steep lapse rates, CAPE greater than
2000 J/kg, effective shear greater than 30 kts, and precipitable
water greater than one inch. Any storm/complex of storms will be
capable of producing large hail, damaging wind, and torrential
rainfall. Of particular concern is the potential for training
convection as Corfidi vectors are oriented perpendicular to moisture
transport vectors, with mean 700-300 mb winds less than 30 kts.
.LONG TERM...(Friday night through Thursday)
Issued at 327 PM CDT Thu Jul 2 2020
Above normal temperatures and chances for thunderstorms, some severe
with heavy rain, highlight the long term period.
Long range guidance continues to favor a stagnant weather pattern
through the middle of next week, with persistent Pacific Northwest
troughing and broad ridging from the Southern Plains to the Upper
Mississippi River Valley. This leaves the local area in an active
southwest to quasi-zonal flow pattern, with mostly above normal
temperatures, humid conditions, and daily chances for thunderstorms.
The hottest day is expected to be Independence Day, with afternoon
heat indices in the mid to upper 90s from south central North Dakota
into the James River Valley.
Forecast instability and shear parameters along with climatology
suggest any round of thunderstorms has the potential to include
severe weather. This thinking is supported by CIPS analogs, which
bring relatively higher probabilities (at least 15 percent) of
severe weather into at least part of North Dakota every single day.
Of greater concern may be the potential for heavy rain. Periods of
strong low level moisture transport are forecast to intercept east-
northeastward propagating MCSs in an environment with above normal
precipitable water and deep warm-cloud layers. This potential threat
looks to be maximized Saturday afternoon through Sunday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 930 PM CDT Thu Jul 2 2020
Scattered thunderstorms are forecast through the forecast period,
mainly across southwest and central ND. Beyond this evening,
predictability of timing and location of storms is low. Expect
periods of IFR to LIFR visibility, sporadic gusty winds, and hail
within thunderstorms. Outside of storms, VFR conditions will
prevail. Wind direction and speeds will be highly variable
depending on where the surface boundary through western North
Dakota meanders to.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM/TWH
SHORT TERM...Hollan
LONG TERM...Hollan
AVIATION...JPM
Area Forecast Discussion
National Weather Service Duluth MN
929 PM CDT Thu Jul 2 2020
.SHORT TERM...(This evening through Friday night)
Issued at 351 PM CDT Thu Jul 2 2020
A high amplitude upper-level ridge in place across the region
will remain in place through the short term. High pressure at the
surface and stagnant flow will result in warm temperatures and
light winds. Scattered showers and thunderstorms have developed
along a lake breeze in northwest Wisconsin this afternoon. MLCAPE
along the lake breeze is 2200-2800 J/kg based on the latest RAP
run and deep layer shear is very weak, around 5 knots. Look for
the weak convergence along the boundary to continue through early
evening. The combination of weak convergence and very low shear
means any storms which develop will be upright and relatively
short-lived. Fog is likely once again tonight, especially for our
Minnesota zones. Visibility of may be as low as one-quarter mile
in spots.
Fog will clear Friday morning with abundant sunshine expected
during the morning hours. Self-destructive Cu will percolate by
late morning and afternoon from north-central to central Minnesota
and east across northwest Wisconsin. With weak forcing and light
winds, a few vigorous cumulus may develop into showers during the
afternoon and evening hours, but kept forecast dry for now due to
low predictability in timing and aerial extent of the showers.
Temperatures will be quite warm with highs in the upper 80s and
low 90s. Areas near the Lake Superior shore may benefit from a
weak lake breeze and will keep temps limited to the upper 70s and
low 80s. Storms are forecast to develop in central North Dakota
Friday afternoon and evening and may push into north- central
Minnesota Friday night and Saturday morning. Have included a
chance of showers and storms overnight to account for that
potential.
.LONG TERM...(Saturday through Thursday)
Issued at 351 PM CDT Thu Jul 2 2020
The forecast for the Fourth of July looks to be very warm with
highs in the upper 80s to low 90s along with a chance for showers
and thunderstorms in the afternoon and evening. These showers and
storms are in association with an approaching MCV from the
Dakotas. MLCAPE of 1000-1500 J/kg and shear values up to 30 knots
should help support thunderstorm development. At this time, SPC
has NE MN under a marginal risk for severe storms. Given the
uncertainty with this system, current confidence in severe weather
is low. The main concern relates to the strength of any
convection that initially develops to the west over the Dakotas.
For Sunday through next week, a trend of diurnal thunderstorms
sets in. The best chance for any widespread convection will be
Monday, as a cold front propagates across the Northland. Upper
level flow transitions from ridging to more zonal for the first
half of the week. This should help to reduce temperatures a bit
with highs in the mid to upper 80s throughout next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 622 PM CDT Thu Jul 2 2020
This afternoon a small line of storms kicked off by the surface
convergence of the lake breeze over NW WI are showing signs of
weakening. These storms will continue to decay and disappear within
the next couple of hours. INL will stay VFR through the TAF period.
Elsewhere, fog is expected to develop overnight once again and
reduce visibilities. Current expectations are for the thickest fog
to be over HYR where LIFR conditions are the most likely. Clear
skies will quickly burn the fog away shortly after sunrise and VFR
conditions will continue through Friday.
&&
.MARINE...
Issued at 928 PM CDT Thu Jul 2 2020
The marine forecast for the next 48 hours looks quiet. High
dewpoints will give way to fog developing tonight and tomorrow night
over the lake. Light winds and waves less than 2 ft will continue
through the period with high pressure remaining in place over the
Northland. Chances of rain return Saturday afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 65 88 61 88 / 10 0 10 20
INL 63 93 64 88 / 0 10 30 40
BRD 66 90 65 88 / 0 10 10 30
HYR 63 92 61 92 / 20 10 10 10
ASX 64 89 60 91 / 10 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...Huyck
LONG TERM...Huyck/Unruh
AVIATION...Britt/LE
MARINE...Britt/LE
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
714 PM CDT Thu Jul 2 2020
.UPDATE...
Issued at 710 PM CDT Thu Jul 2 2020
Have increased PoPs to likely for tonight over the S/W due to
latest radar trends.
Latest SPC Mesoanalysis places 4000-4500 J/kg of MLCAPE over SW/W
portions of the CWA, with effective deep layer shear rather weak
at 25-30kt. Convection over SW NE/NE CO has grown upscale into an
organized/mature QLCS with a general motion to the ESE around
30kt. This would place arrival time to Furnas Co area around
0030-0100Z. This activity has generated a significant cold pool
(air temps in low to mid 60s under/behind line of tstms) and
several 50-70mph gusts have been reported...including 74mph just W
of KMCK. Given the weak deep layer shear, linear mode, organized
cold-pool...fairly high confidence that the greatest threat will
be strong-dmg winds of 50-70mph. Question is how long this will
last? While expect a gradual weakening trend, the current trends
suggest a svr threat will probably exist for at least areas from
Elwood to Stockton...with E extent of svr risk possibly as far E
as EAR to HJH. 0-3km shear vectors as well as Corfidi vectors
turning more SE-SSE suggests this activity should turn a bit as
this activity spreads E toward 04Z-05Z. Diurnal decr in
instability should help tstms gradually decr toward 06Z. Like the
general idea of both the HRRR and HRRREXP, though both are 1-2hr
too slow.
Reference SPC MD #1086 for latest thoughts on potential new watch.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 500 PM CDT Thu Jul 2 2020
Covering the first first 5 periods/60 hours in this section, by
far the main challenge are VERY tricky-to-forecast
rain/thunderstorm chances (PoPs), while confidence is considerably
higher in other elements such as high/low temperatures and winds.
To be very honest, these type of "summery" weather patterns with
subtle forcing aloft drive this forecaster nuts, because although
we "know" that most areas will be dry most of the time, there is
just enough potential for storms to mainly either roll in from
the west off the High Plains and/or form "randomly" overnight
along little low-mid level convergence zones (mainly rooted
between 850-700 millibars), that we just have to keep various low
PoPs in the forecast. Some of these low chances will certainly not
come to fruition, but others likely will.
As for severe thunderstorm potential:
By far our main concern (and the one that carries any kind of
modest-confidence at all) comes right away this evening-tonight,
as the potential exists not only for spotty/more isolated activity
almost anywhere, but also for possibly a more organized storm
complex/mesoscale convective system (MCS) rolling in from the
west. SPC currently has mainly western portions of our CWA
assigned a Marginal to Slight Risk of severe, and if anything,
kind of wish they would have more of our central counties in the
Marginal as they had in the previous outlook, as a severe threat
could easily extend to at least Highway 281 later if models such
as the HRRR/NAMNest are onto anything.
Briefly looking at the current/recent weather scene as of 430 PM:
Overall, it`s been a dry day CWA-wide once the somewhat-unexpected
early morning showers/storms in our far southeast zones faded
away. Aloft, large-scale ridging dominates, but subtle embedded
waves along with upslope low-level flow to our west has really
ignited quite a bit of convection (some severe) to our west in the
CO/KS/NE border area. At the surface, east-southeast breezes of
generally 10-15 MPH with some higher gusts to around 20 MPH or
slightly higher have prevailed today. High temps have topped out
mainly upper 80s-low 90s.
In the interest of time, will finish this section with some
abbreviated comments on the next 5 night/day periods...
This evening-overnight:
See our latest Hazardous Weather Outlook (HWOGID) for our general
expectations, but while the entire area will be prone to at least
spotty convection at some point, our biggest concern will be with
whether a more organized MCS will roll in from the west sometime
after 7-8 PM. Worst-case scenario is a corridor of damaging winds
of 70+ MPH, but with relatively weak ambient shear, this will
depend more on how organized of an eastward-surging cold pool that
storms to our west can form. Even late in the night, would not be
surprised to see "random" showers/storms bubble up along mid-level
boundaries (much as what happened in our southeast this morning).
Low temps mid 60s west to around 70 east.
Friday daytime:
While confidence is high that most areas will be dry most of the
day, lingering activity from the overnight hours (likely non-
severe) could occur at least into the morning mainly within the
eastern half of the CWA, and have this covered with low PoPs. For
the afternoon, took a small chance and removed PoPs, calling for
dry conditions as any storm development should remain well to our
west. Otherwise, very similar to today temp-wise, with highs
mainly a few degrees either side of 90. Breezes also similar,
generally 10-15 MPH from the southeast with some higher gusts.
Friday night:
Although am not expecting nearly the potential for possible storms
that tonight holds (especially those rolling in from the west),
felt it was prudent to at least carry some basic slight chances
given continued subtle forcing overnight. Likely dry for most
areas though. Low temps upper 60s to around 70.
Saturday daytime (Independence Day):
Like today was and tomorrow should be, confidence is fairly high
that the vast majority of the CWA remains dry, with simply another
warm day with highs upper 80s-low 90s and slightly-breezy
southeast winds. That being said, this is just far enough out in
time that it falls into the time frame where our "default" multi-
model blend is more "in control" of the forecast, and because it
insists on some small rain chances being around, we continue to
call for low-confidence slight chances most areas.
Saturday evening-night:
Much like the daytime period, most raw model data leans toward a
dry evening-night for outdoor activities. However, especially our
far western counties could see some potential for evening storms
TRYING to drift in from the west. For now, will run with some
slightly toned-down Pops from the default multi-model blend, with
mainly 30 percent chances west and only 20s (slights) east. Low
temps aimed mid-upper 60s.
.LONG TERM...(Sunday daytime through Thursday)
Issued at 500 PM CDT Thu Jul 2 2020
General overview of this 5-day period:
Carrying the same theme of from the short term above, there is
certainly more confidence regarding temperatures through this time
frame than in "exact" rain/thunderstorm chances (PoPs). To put it
bluntly, this is just a very "murky" weather pattern when it comes
to having any great confidence in PoPs. In the mid-upper levels,
we spend the vast majority of this time frame in a fairly weakly-
forced, "typical" mid-summer weather pattern, as we reside south
of the main upper jet axis that generally resides from the western
through north-central CONUS. Thanks to the predominant ridging,
mid level temps will be warm enough on most afternoons to likely
prevent convection from firing in the absence of stronger forcing.
That being said, we will certainly be prone to occasional
storms/complexes wandering in from the west during especially the
evening, along with very subtle low-mid level warm air advection-
induced activity (mainly rooted 850-700 millibars) during the
overnight and perhaps morning hours on some days.
Precipitation/thunderstorm chances:
Needless to say, this forecast is simply littered with low
confidence thunderstorm chances, affecting at least portions of
the CWA each and every day and night. While the vast majority of
night and especially days will likely remain dry, these small
(mainly 30 percent or less) PoPs clearly outline the uncertainty
in the forecast. Obviously we will attempt to refine
(increase/decrease) these POPs as periods move into the shorter-
term range, but for now we just have to live with them all. As for
severe storm chances, they are certainly not zero, especially
given what will likely be appreciable instability much of the
time, but given overall weak shear, it will difficult to forecast
organized storm potential very far in advance. However, could
certaintly foresee at least a few Marginal/Slight risk setups
during this time.
Temperature overview:
Certainly, there is higher confidence here. Although the presence
of pesky clouds and/or storm outflow could easily throw things off
by 5+ degrees on a few days/nights, certainly the majority of
these 5 days looks to feature highs between the upper 80s-mid 90s
(some upper 90s more favored southwest), and overnight lows
between the mid 60s and low 70s. In other words, a seasonably-hot,
but not overly-hot weather pattern (not the type that would
require formal Heat Advisories).
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 640 PM CDT Thu Jul 2 2020
Significant wx: Potential storms/outflow this eve, MVFR cigs near
dawn
Tonight: VFR to potentially MVFR. Generally low confidence period
due to unknown track of storms off to the W. At the minimum, will
get BKN to OVC cirrus, but depending on the track, both terminals
may get side swiped by the convection, with generally better chcs
just off to the S. Given uncertainties in track, kept VCTS for
now, but did indicate a likely switch in wind dir 03Z-05Z to SW
or W, due to outflow from this convection, as well as bring in
some low cigs that could potentially be MVFR. Short term models
exit/weaken the convection around 06Z. Can`t completely rule out
additional elevated convection late overnight, but too low of
potential to include attm. Finally, some models indicate BKN MVFR
cigs near dawn for GRI, with maybe even lower cigs and patchy MVFR
fog poss as well. Again, though, this is low confidence as will
depend on convective trends.
Fri: MVFR to VFR. Any low cigs should scatter and lift by mid-
morning...leaving VFR conditions and occasional mid to high clds.
Winds will be SE 6-10kt. Confidence: Medium.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...Thies
SHORT TERM...Pfannkuch
LONG TERM...Pfannkuch
AVIATION...Thies
Area Forecast Discussion
National Weather Service Wichita KS
923 PM CDT Thu Jul 2 2020
.UPDATE...
Issued at 923 PM CDT Thu Jul 2 2020
Diurnally driven convection, along a diffuse outflow boundary has led
to convection propagating to the NW towards the convective complex
currently moving east out of NW KS. The bigger concern, now, is the
strong/severe complex of storms moving E into KHYS and what is the
path of this complex of storms late this evening and overnight.
Current RAP propagation vectors suggest that this complex will
continue to move E-SE as it progresses into central KS, possibly
taking more of a turn to the SE with time towards McPherson and
Marion, as the complex follows the main instability axis to the SE.
Could see damaging winds along the bowing segment with heavy
rainfall as well, given the very unstable airmass. After
coordination with SPC, gonna issue a SVR Watch for portions of
central KS for the damaging wind threat.
Ketcham
&&
.SHORT TERM...(This evening through Sunday)
Issued at 300 PM CDT Thu Jul 2 2020
Morning convection which moved across the southern Flint Hills
has evolved into a decent MCS this afternoon across eastern
Oklahoma. This has stabilized much of the area in the wake of
the outflow boundary which arches from central Oklahoma into
portions of southwest Kansas. This will focus the more robust
convection west of the forecast area late this afternoon. As the
weak mid-level flow becomes more northerly this evening, it may
tend to keep much of this convection from developing/moving too
far east into central Kansas. However, airmass recovery is
expected within the reservoir of elevated low level moisture
across central and eastern Kansas later this evening, so will
expand slight/modest PoPs overnight. Weak northerly flow aloft
looks to be maintained across the area through Independence Day
with instability axis across eastern Kansas. While chances for
organized convection look low, cannot rule out a few storms the
next few days. Temperatures should average near or slightly above
early July climo, though will likely stay just below the 105 heat
advisory criteria.
Darmofal
.LONG TERM...(Sunday night through Thursday)
Issued at 300 PM CDT Thu Jul 2 2020
Upper ridge will retrograde across the Southwest CONUS late in
the weekend through early next week as weak troughing over the
high Plains migrates across the area. This may provide modest
precip/convective chances across the area.
KED
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 700 PM CDT Thu Jul 2 2020
Diurnally driven convection continues across south central KS and
extreme SE KS at this time. Most of the convection is flirting with
the KHUT/KGBD and KCNU taf sites. Current propagation of the south
central KS storms, are moving to the NW, towards the KGBD taf site.
So will go with VCTS for the KGBD and KHUT taf sites. Will also
include VCTS for the KCNU taf site, as outflows from the convection
to east of CNU may propagate back to west. Think most of the
convection is diurnally driven, with most of the convection expected
to wane a couple of hours after sunset.
VFR conditions are expected overnight into Fri.
There is another chance of isolated storms across south central KS
on Fri afternoon. For now, will not include a VCTS in for this
chance, as pinning down the location of any storms is too far out to
pinpoint just yet.
Ketcham
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 72 95 71 94 / 30 20 20 20
Hutchinson 70 95 70 94 / 50 20 20 20
Newton 71 94 70 93 / 50 20 20 20
ElDorado 70 93 70 92 / 30 20 20 20
Winfield-KWLD 73 94 72 93 / 30 20 20 20
Russell 68 94 69 93 / 60 10 20 20
Great Bend 68 95 69 94 / 60 10 20 20
Salina 71 94 70 93 / 50 20 20 20
McPherson 70 94 69 93 / 50 20 20 20
Coffeyville 74 93 72 92 / 20 30 20 20
Chanute 73 92 72 91 / 20 30 20 20
Iola 72 91 71 90 / 20 30 20 20
Parsons-KPPF 73 92 72 91 / 20 30 20 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Ketcham
SHORT TERM...KED
LONG TERM...KED
AVIATION...Ketcham
Area Forecast Discussion
National Weather Service Phoenix AZ
810 PM MST Thu Jul 2 2020
.SYNOPSIS...
As high pressure builds into the region, a warming trend will allow
highs to climb back above normal by this weekend, and continue well
into next week. While there is a very slight chance of thunderstorms
for parts of south-central Arizona this evening, much of the area
likely will not experience storms directly. However, some wind and
dust would be more common. A drying trend beginning this weekend
will not favor storm development for the holiday weekend and early
next week.
&&
.DISCUSSION...
Though not particularly evident in satellite imagery, objective
analysis suggests a subtle midlevel perturbation propagating through
south-central AZ this evening providing just enough support to spur
a couple isolated storms in an otherwise convectively marginal
environment. 00Z KPSR sounding data sampled only 9 g/kg mixing ratio
extending through the sfc-H7 layer yielding MLCape just at 300 J/kg,
but still a notable CinH nose just above the top of the boundary
layer. KTWC sounding data had slightly better moisture profiles (10
g/kg) with only somewhat better thermodynamic measures.
The aforementioned wave infusing or concentrating moisture into the
CinH layer along with some weaker outflow boundaries did eventually
get some storms going in an environment rich with DCape values in
excess of 1000 J/kg. Individual storms have easily produced
concentric outflows (generally isolated gusts 40 mph), though thus
far these outflows have been fairly shallow and weakening rather
quickly after spreading from the initial downdraft (although still
traveling a good distance from their initiation and kicking up
localized dust). The isolated nature hasn`t produced deeper or more
consolidated outflow yet that would be necessary to displace the
entire boundary layer and erode a larger expanse of the inhibition
aloft. However, the recent storms in western Pinal County have
displayed better linear outflow and impetus for new storm
development. That said, a cooling boundary layer and output from
high res models which have been moderately accurate this evening
(i.e. HRRR and ARW core) don`t offer much hope of storms lasting
much longer into the evening. Boosted POPs in this area of interest
for the remainder of the evening, and made some adjustment of other
parameters based on recent observational trends.
&&
.PREVIOUS DISCUSSION...
/445 PM MST Thu Jul 2 2020/
A warming trend gets underway on Friday as the ridge continues to
work its way west closer to the region. Above normal highs will
climb to near 108 to 110 by Saturday and remains near 110 through
Tuesday. With significant moisture in place a weak disturbance over
AZ along the NW flank of the ridge could trigger some isolated
thunderstorms mainly across the N AZ high country on Friday into
Saturday. The ridge will also likely keep additional storms confined
mainly to SE and far E AZ for the late tomorrow afternoon and early
evening.
Also beginning Friday is a gradual zig-zag drying trend as the ridge
axis retrogrades further to the W-SW and moisture and instability
along the S flank of the ridge will keep the best storm chances
confined mostly to SE AZ and NW MX for early next week with only
very slight chances for a renegade storm in the lower deserts or
closer to Phoenix. In addition, moisture continues to gradually
decrease with ensemble mean regional PWs falling to generally less
than 1" during the weekend.
&&
.AVIATION...Updated at 2345Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Fairly low confidence aviation forecast through Friday afternoon
with variable wind directions through early this evening, then the
potential for a weakening outflow boundary later in the evening.
Winds will likely keep a 160v230 heading into mid evening before the
preponderance of models suggest finally switching to SW, and
persisting into the overnight. The switch back to east may be
delayed until sunrise, or possibly later. TS activity should remain
well southeast of terminals and dissipate a few hours after sunset
with only some high clouds streaming into central AZ. Conditions
should return to a more quiet, stable pattern Friday afternoon.
Southeast California/Southwest Arizona including KIPL and KBLH:
Very little aviation concerns will exist through Friday afternoon
under mostly clear skies. Winds at KBLH will favor a southerly
direction though the typical period of variability of light north
drift will be likely Friday morning. KIPL winds may briefly become
gusty during the mid evening as directions switch to the west,
however trends in directional shifts should be similar to the past
couple days.
&&
.FIRE WEATHER...
Sunday through Thursday:
No changes to the fire weather outlook...Significantly above
normal highs near 110 continue through around Tuesday with highs
staying above normal through the period. A gradual drying trend
continues through midweek. However, there is still a very slight
lingering chance of a few isolated storms focused over higher
terrain areas of the eastern districts though rainfall may not be
very widespread or heavy with any isolated storms. Afternoon
minimum humidity values will generally fall between the single
digits in the far west and the low to mid teens elsewhere, while
overnight maximum RHs look to vary between 25-40%. Typical
afternoon breezes with gusts up to 18-24 mph will be likely with
some localized stronger outflow winds possible near any renegade
storms.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...MO/Sawtelle
AVIATION...MO
FIRE WEATHER...Sawtelle/Smith
Area Forecast Discussion
National Weather Service Springfield MO
628 PM CDT Thu Jul 2 2020
...00Z AVIATION UPDATE...
.SHORT TERM...(This evening through Friday)
Issued at 240 PM CDT Thu Jul 2 2020
Hot and humid conditions are in place across southwest Missouri and
southeast Kansas this afternoon. Did go ahead and upgrade heat
advisory to an excessive heat warning for McDonald and Newton
counties, where slightly higher dew points have raised heat index
values above 110.
12Z SGF sounding shows all the moisture confined below 850mb (Approx
5000 feet), with very dry air above this. RAP does indicate a little
better moisture pushing into southwest Missouri and far southeast
Kansas this afternoon and evening. Expect Isolated thunderstorms
into the evening hours as surfaced based instabilities of 5500-6000
j/kg are present, with weak shear. Best chances for any stronger to
potentially severe would be in this corridor of higher moisture over
southwest Missouri into southeast Kansas. These will likely weaken
with loss of heating, but given the humid airmass, much like last
night will likely see isolated showers/storms through the overnight
hours.Look for lows tonight mainly in the lower to middle 70s.
Temperatures will be somewhat cooler on Friday, with highs ranging
from the middle 80s in the eastern Ozarks to the lower 90s in
southeast Kansas and far southwest Missouri. It will remain quite
humid though, but heat index readings at this point look to remain
below advisory levels, generally in the mid to upper 90s and
perhaps 100 over southeast Kansas, so at this point no advisory
headlines will be issued. With the heat and humidity will once again
see the possibility of isolated to scattered storms during the heat
of the day. No widespread severe weather is expected, but as it
typical this time of year could see an isolated stronger storm.
.LONG TERM...(Friday Night through Thursday)
Issued at 240 PM CDT Thu Jul 2 2020
This period will be dominated by a persistent upper level ridge over
the area. This will keep warm and humid conditions for the area with
at or above normal temperatures. Daily, mainly diurnally driven
convection will occur, but plenty periods of dry weather.
Temperatures actually look to cool a bit for the upcoming weekend
with highs in the upper 80s to around 90. Weak surface high pressure
looks to build in from the north on Sunday, and this will likely be
the "driest" day of the weekend. Otherwise, temperatures begin to
climb back up into the 90s by the middle part of next week with heat
indices once again topping 100 degrees in many locations.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 624 PM CDT Thu Jul 2 2020
Thunderstorms will start the TAF period at BBG however should
remain dry at JLN and SGF. VFR conditions are expected at the
sites through most of the period. Could be some brief MVFR around
12Z however confidence is not high enough at this time to include.
winds will remain light and out of the northeast generally. There
is a chance for additional showers and storms Friday afternoon
however confidence is too low at this time.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory until 8 PM CDT this evening for Moz066-077>079-
088>090-094>096-102>105.
Excessive Heat Warning until 8 PM CDT this evening for MOZ093-
101.
KS...Heat Advisory until 8 PM CDT this evening for KSZ073-097-101.
&&
$$
SHORT TERM...Raberding
LONG TERM...Raberding
AVIATION...Burchfield
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
801 PM EDT Thu Jul 2 2020
.AVIATION...
Prevailing VFR through the period with persistent westerly
flow. Winds will subside tonight but begin to pick up to AOA 12
knots late morning into afternoon hours, perhaps becoming gusty at
times. VCSH starting out early in TAFs, transitioning to VCTS by
17-18z. Lower rain chances across southern terminals so therefore
have left out any rain mention for FMY/RSW.
&&
.MARINE...
West-southwest winds generally around 10-15 knots will prevail
over the gulf coast waters as high pressure ridges over southern
Florida. Daily scattered showers and an isolated thunderstorm will
be possible each day with the highest chances north of Tarpon
Springs earlier in the day. No headlines are expected and the only
hazards expected through the end of the week and into the weekend
will be associated with higher winds and seas as well as
dangerous lightning associated with passing thunderstorms.
&&
.Prev Discussion... /issued 630 PM EDT Thu Jul 2 2020/
UPDATE...
Broad cyclonic flow aloft continues as the axis of a midlevel
trough extends from SW-NE across the Atlantic seaboard. This flow,
coupled with eastern Gulf SST in the mid to upper 80s (leading to
MLCAPE around 1500 J/kg over the waters according to RAP
analysis), has maintained sporadic showers and an occasional
thunderstorm or two moving into the central nearshore waters.
However, these are rather small in coverage and brief due to the
quick eastward movement. A decrease in low-level lapse rates over
the waters should be just enough shut this convection off shortly
after sunset. Likewise, we will also see any stray shower or storm
over land dissipate when we loose daytime heating... Convection
will once again fire off over the northwest waters overnight,
gradually working their way southward towards West Central Florida
by early morning. Only have made adjustments to short-term PoPs
to account for current trends and forecast thinking.
&&
.Preliminary Point Temps/PoPs...
TPA 92 80 91 79 / 20 10 50 40
FMY 93 79 93 79 / 10 0 20 10
GIF 93 76 93 76 / 30 10 70 20
SRQ 91 80 91 79 / 30 20 30 20
BKV 92 75 91 74 / 20 10 70 50
SPG 92 80 91 79 / 90 10 40 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...Norman
UPPER AIR/DECISION SUPPORT...Rude