Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/12/19
Area Forecast Discussion
National Weather Service Bismarck ND
859 PM CDT Sun Aug 11 2019
.UPDATE...
Issued at 858 PM CDT Sun Aug 11 2019
Latest radar shows moderate rain over south central ND with
isolated thunderstroms confined near/along the southern border.
Additional isolated showers were developing in the southwest.
Farther upstream, a line of thunderstorms stretching from just
west of Glasgow to Billings have been near severe to severe at
times. Large scale ascent will become maximized in far eastern
Montana and western North Dakota around 06z/1AM CDT, then pivot
through overnight into Monday morning. There will be heavy rain,
perhaps more focused in the west and north central. The other
concern will be the possibility for damaging winds west into
central overnight as the aforementioned line arrives into western
North Dakota around 06z. Gust front convergence may develop as
strong low level easterly flow remain pointed into the mean deep
layered winds which are west to southwest aloft. The HRRR and
ESRL HRRR are beginning to show signs of a bowing segment
developing towards Bismarck between 10z and 12z Monday. Will
continue to monitor conditions from Montana into western ND over
the next few hours.
UPDATE Issued at 602 PM CDT Sun Aug 11 2019
Multiple rounds of showers and thunderstorms with heavy rainfall
continues to be the main hazard this evening/tonight. Heaviest
rainfall totals this evening occurred in Bowman and near New
England with around 2 inches in one hour. Soil moisture has been
able to handle this well, but will monitor for future rounds and
location. Movement of these heavier showers and thunderstorms have
been progressive, which is helping to inhibit flash flooding
potential. Uncertainty on exactly where and how many more rounds
will actually develop remain high, as the CAMS are all over the
place in terms of possible scenarios.
&&
.SHORT TERM...(This evening through Monday)
Issued at 259 PM CDT Sun Aug 11 2019
A severe thunderstorm threat exists for far southwest North
Dakota this afternoon and evening with large hail, damaging wind
gusts, and a nonzero tornado chance possible. Additionally, heavy
rainfall and several rounds of thunderstorms in the southwest to
south- central may cause a flash flooding concern overnight.
This afternoon, the synoptic pattern was characterized by a potent
shortwave rounding the Great Basin region with a 500mb speed max
pushing into the northern Rockies. Smaller impulses were detected on
water vapor imagery pushing over central Montana and northern
Wyoming. At the surface, pressure falls were noted in southern
Montana and northern Wyoming where cyclogenesis and convergent
upslope flow was ongoing. In north-central through southeast
North Dakota a surface high axis was in place. Widespread stratus
was detected on visible satellite imagery within the western and
southern peripheries of the surface high, extending from western
North Dakota through the James River Valley. In the southwest
through south-central, skies have been clearing with the
subsequent development of a cumulus field over the last several
hours.
A severe thunderstorm threat is expected to develop late this
afternoon and evening in southeast North Dakota. Surface dew
points in the low 60s beneath midlevel lapse rates of 7-7.5 C/km
will develop MLCAPE values in the 1000-2000 J/kg range. Strong
midlevel flow marked by 30-40 kts of effective bulk layer shear
will combine with this instability to create a potential severe
thunderstorm parameter space. With generally unidirectional
hodographs depicted in southwest ND forecast soundings, splitting
cells with eventual storm mergers will be likely. Thus the severe
threat at the moment seems to be contained mostly to our southeast
counties where initial cells may produce large hail and locally
damaging wind gusts before becoming congealed. Additionally given
strong deep layer shear, ML LCL`s around or below 1000m, and
potential for discrete supercells...a tornado risk does exist. 0-1
km SRH is rather low, though the other ingredients is enough to
make it a risk worth highlighting.
This evening, thunderstorm coverage is expected to increase across
our southwest as the midlevel speed max exits the Rockies.
Thunderstorms are forecast to develop in central Montana and move
into the northwest counties by late this evening as well. By the
time of their arrival they will likely be clustered and elevated so
the severe risk further north is low. Heavy rain will be a concern
with thunderstorms tonight as PWAT values of 1.25" to over 1.5" will
continue to advect northward this evening. Widespread rainfall
totals of 1 to over 2 inches will be possible. In the southwest
where several rounds of convection are likely this evening and
tonight, the totals may be greater. HREF guidance indicates areas of
2 to 4 inches will be possible in the southeast to south-central
counties given multiple thunderstorm passages. That said, the lack
of a reinforcing mechanism to redevelop thunderstorms in one
location does tone down the flash flood threat some. Though storm
propagation should be fast enough to mitigate flash flooding
concerns, this will still need to be closely monitored especially
if a couple thunderstorms move over more populated areas.
Scattered showers and isolated non-severe thunderstorms will
continue through northern and eastern North Dakota early Monday
morning before dissipating by mid-day. While the midlevel low is
expected to briefly close off early Monday, guidance shows it
becoming more progressive through the day and begin to move
southeastward from northeast Montana through southeast North Dakota.
A relatively thin instability corridor ahead of an advancing surface
trough will pose a marginal severe threat Monday afternoon in the
central and southeast. This will be highly conditional on daytime
clearing and destabilization.
Lingering precipitation and cloud cover Monday will also lead to
cooler temperatures with highs in the 60s north and east to 70s
south and west expected.
.LONG TERM...(Monday night through Sunday)
Issued at 259 PM CDT Sun Aug 11 2019
The long term forecast period is highlighted by almost daily chances
for showers and thunderstorms with the active period continuing
through the weekend.
Monday evening the previously closed midlevel low rejoins the flow
and dives southeastward through the Dakotas, dragging an attendant
cold front through the area overnight. Pressure rises behind the
front may bring breezy overnight winds however the magnitude is
fairly uncertain given this occurring through the diurnal minimum
and boundary layer decoupling. Some lingering showers will be
possible Tuesday though the trend will be towards clearing with a
surface high developing beneath midlevel height rises. NAM/GFS MOS
guidance shows widespread high temperatures of mid 60s to around
70s likely Tuesday afternoon though the ECMWF has been a few
degrees warmer. NBM blend of upper 60s to around 70 captured this
well.
Wednesday through Friday, the synoptic pattern is characterized by
generally northwest flow aloft with daily chances for showers and
thunderstorms. Midlevel flow stays fairly strong through the period
so chances for severe weather in the region continue through the
week (though uncertain in coverage and location at the moment).
This weekend, ensemble and deterministic guidance has been
consistent in developing a strong northwest trough and tracking it
eastward through the weekend. While run to run details in wave
timing, return flow, etc have been inconsistent...ensemble guidance
in the CIPS analogs and GEFS plumes have shown some sort of signal
for higher chances of thunderstorms and possibly severe weather.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 602 PM CDT Sun Aug 11 2019
Showers and thunderstorms highlight the taf period through 12z
Monday, with possibly more precipitation across the northern
terminals Monday afternoon. Heavy rainfall will result in MVFR
to IFR cigs/vsbys at times. Expect the precipitation to wane from
west to east 06z-12 Monday. Should see a break through 18z with
MVFR cigs improving to low vfr. More showers/thunderstorms are
forecast after 18z Monday, mainly over the northern and south
central terminals of KISN/KMOT/KBIS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...AE
LONG TERM...AE
AVIATION...KS
Area Forecast Discussion
National Weather Service Cheyenne WY
954 PM MDT Sun Aug 11 2019
.UPDATE...
Issued at 947 PM MDT Sun Aug 11 2019
All severe weather hazards have ended for the evening and updated
zones and hazardous weather outlook have been posted.
The convective cloud shield from earlier showers and storms and
ongoing activity in central Nebraska to Colorado remain over the
western Nebraska Panhandle this hour. Low cloud ceilings continue
at KSNY due to all the rainfall an boundary layer moisture present
underneath the convective cloud shield. With all the rain that did
fall today in the Panhandle - expected areas of low clouds and fog
overnight in the Panhandle and perhaps towards Niobrara County as
well. Patchy IFR ceilings and visibilities will need to be
monitored for and likely incorporated in the 06Z TAF cycle.
Much drier conditions expected Monday and Tuesday where a Red Flag
Warning and Fire Weather Watch highlights are in place in SE WY.
Don;t have high enough confidence on issuing a Red Flag Warning at
this time for the High Plains of WY given the marginality of the
winds and humidity plus the rain that did occur today. Will let
overnight shift assess latest trends.
UPDATE Issued at 130 PM MDT Sun Aug 11 2019
Severe thunderstorm watch #570 in effect till 8 PM MDT for all
Nebraska Panhandle Counties and the following counties in
southeastern Wyoming, Converse, Niobrara, Platte, Goshen, and
Laramie Counties.
UPDATE Issued at 1219 PM MDT Sun Aug 11 2019
Storm Prediction Center with their 16z update have continued the
trend for overall slight risk of severe weather this afternoon.
Trended PoP and QPF values to reflect a blend of the HRRR, GFS,
and NBM to cover the main spatial trends. Thinking the convective
initiation of the HRRR is too far eastward considering the last
couple hours of KCYS radar reflectivities and beginning of storms
now along the Southern Laramie Range. Main threats remain strong
thunderstorm winds, hail upwards of 2 inches possible along with
an isolated tornado or two. Storms should begin as initial
supercells on the WY high plains before consolidating into an
eventual bowline structure. Dewpoints at the moment sitting in the
60s from the Laramie Range eastward into the NE Panhandle. Main
timing of storms will be from about 1 PM through 8 PM.
&&
.SHORT TERM...(Today through Monday Night)
Issued at 200 AM MDT Sun Aug 11 2019
Severe thunderstorms today...followed by fire weather concerns
Monday are the forecast challenges this morning.
Currently...Complex situation across the area this morning. First
off...a hug MCS has developed over northwestern Kansas and
southwestern Nebraska this morning and shows no signs of
weakening. Most of northern Kansas and southern Nebraska is under
this MCS. Water vapor imagery showing a good plume of subtropical
moisture in eastern Utah and western Colorado this
morning...lifting north into south central Wyoming at this time.
Latest GFS PWATS showing close to 1.0 inch in this plume as it
moves into our area. Off to the northwest...a Pacific low pressure
system is currently tracking across eastern Oregon...moving
northeast into western Montana. Finally on surface analysis...we
have a surface boundary that looks to be laying along the east
slopes of the Laramie Range...northwest into southwestern Montana.
East of this front...dewpoints in the 60s being observed in the
Panhandle...with 40s in Albany County and northwestern Colorado.
Models remain consistent on the solution for todays forecast. A
disturbance in the monsoonal flow is forecast to tracks into
northeastern Colorado and southern Nebraska Panhandle by this
afternoon. This disturbance...along with the northwestern low are
expected to begin lifting the stationary surface front to the
northeast this afternoon as a warm front. Mesoscale guidance
showing developing over the Laramie Range around 18Z...lifting
northeast along the warm front as the afternoon progresses.
Signatures on simulated radar from HRRR and Hires-NMM initially
showing discrete supercells that form into bowing segments in the
northern Panhandle as they move northeast. GFS surface based CAPE
initially around 1500 J/KG at 18Z...increases to 2500-3000J/KG by
21Z across Niobrara County and northern Panhandle by 21Z. 0-6km shear
increasing to 40-45kts should be sufficient for supporting these
supercells. Do expect all modes of severe convective weather to
develop with these storms today.
Warm front looks to clear the northern Panhandle by mid
evening...a little slower than what we were seeing 24 hours ago.
Held onto high PoPs in the Panhandle through 03Z before decreasing
at 06Z.
Very dry air behind the front begins to shift into southwest
Wyoming after 06Z and into Carbon County by 12Z Monday. GFS
showing PWATS down to .2 to .3 inch across Carbon County by that
time with 700mb winds increasing to 25-30kts. Still very confident
in critical fire weather conditions developing over southwestern
and western Carbon County Monday late morning that continues into
the early evening. Decided to upgrade the Watch for southwest
Carbon County (FWZ 304) to a Red Flag Warning for Monday.
Confidence not so high for FWZ 310...so left as a watch for the
time being. Am not getting the lower humidity at this time...only
getting down to the upper teens over western Laramie and Platte
Counties Monday afternoon. Will give the day shift another look to
see what the 12Z guidance shows.
.LONG TERM...(Tuesday through Saturday)
Issued at 200 AM MDT Sun Aug 11 2019
Tuesday...Northwest flow aloft prevails. With a surface boundary
across our eastern counties and adequate low and mid level moisture,
we may see isolated afternoon and evening thunderstorms along and
east of a Cheyenne to Chadron line.
Wednesday...Although the flow aloft remains northwest, warmer
temperatures aloft and a drier airmass will likely limit any shower
or thunderstorm development. This will also aid in a decent warming
trend.
Thursday...The low amplitude ridge axis moves off to our east and
temperatures will continue to warm with 700 mb temperatures near 16
Celsius. The cap may be just weak enough to allow for isolated
thunderstorm development east of a Douglas to Cheyenne line in the
evening.
Friday...The flow aloft backs to southwest. As a low level boundary
develops over our eastern counties, we may see isolated late day
showers and thunderstorms east of a Douglas to Cheyenne line.
Saturday...Mostly dry due to warm temperatures aloft limiting
convective potential under southwest flow aloft.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 554 PM MDT Sun Aug 11 2019
Ongoing convection across the NE Panhandle expected to continue
for the next few hours with brief periods of MVFR conditions in
heavy thunderstorm rain bands. Some erratic winds may be possible
as well. Clearing behind the storms will continue on the WY side
and into NE later this evening with ceilings becoming FEW to SKC
as drier air is advected in.
&&
.FIRE WEATHER...
Issued at 1220 PM MDT Sun Aug 11 2019
Widespread isolated to scattered showers and thunderstorms
possible this afternoon ahead of shift in drier atmospheric
conditions. Fairly dry conditions expected to persist through the
week allowing for additional curing of fuels and increased risk
for wildfire spread. Critical fire weather conditions still on
track for FWZ 304 for Monday. RH levels and winds for FWZ 310 on
Monday still seem borderline to hold the watch for another model
cycle seeing as convection this afternoon may wet fuels enough to
limit fire growth tomorrow.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning from 11 AM to 7 PM MDT Monday for WYZ304.
Fire Weather Watch from Monday morning through Monday evening
for WYZ310.
NE...None.
&&
$$
UPDATE...JSA
SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...WM
FIRE WEATHER...WM
Area Forecast Discussion
National Weather Service Dodge City KS
1025 PM CDT Sun Aug 11 2019
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
Issued at 1023 PM CDT Sun Aug 11 2019
WV imagery indicates a southwest flow aloft prevailing across the
Western High Plains. Meanwhile, an upper level shortwave trough is
pushing eastward across the Pacific Northwest. Near the surface,
an area of low pressure is anchored in southeast Colorado with an
attendant frontal boundary extending eastward through western
Kansas.
&&
.SHORT TERM...(This afternoon through Monday)
Issued at 1130 AM CDT Sun Aug 11 2019
Last night`s MCS was exiting eastward through Missouri at midday,
with sunshine, an increasing south wind, and a few degrees of
warming expected this afternoon. Most locations will warm well
into the 90s this afternoon, with a few locales near the Oklahoma
border reaching 100. Boundary layer moisture is still very high,
with surface dewpoints within a few degrees of 70, all the way
back to the far western zones. As such, instability will mount
quickly again this afternoon, with CAPE increasing to near
3000 J/kg and lifted indices falling to -7C. Triggering
mechanisms are again limited this afternoon, but a weak
disturbance approaching from the south (producing thunderstorms
near Amarillo at midday) may generate some isolated convection
focused on the southern/SW zones through 7 pm as the latest HRRR
iterations suggest.
Around 7 pm this evening, all models are unanimous showing strong
thunderstorm development/organization in NE Colorado, as stronger
shortwave forcing arrives off the Rockies. 12z NAM and most of the
CAMs/HRRR show a strong MCS rolling through WFO Goodland`s CWA
this evening/tonight, into SW Nebraska. This MCS will probably
have more severe wind associated with it tonight compared to last
night`s previous MCS, but am confident the vast majority of
thunderstorm activity will bypass SW KS to the north. Kept the
scattered/chance category pops across the northern zones tonight
as inherited, and as 12z NAM suggests, but these are likely
overdone. Despite saturated soils across Trego county and vicinity
after last night`s MCS, feel no need to issue another flash flood
watch for tonight. A low level jet is expected this evening, with
12z NAM increasing SW 850 mb winds to near 50 kts, feeding the
MCS to the north. This will keep south breezes elevated in SW KS
this evening and slow the diurnal temperature drop. After
midnight, a weak cold front/outflow boundary/wind shift will
deliver a light NW wind shift through Monday morning, allowing
areas west of US 283 to fall into the 60s.
The light NW/N winds behind the boundary will offer several
degrees of cooling on Monday, and with MOS guidance trending
slightly cooler, trimmed Monday`s max temperatures some back to
the lower 90s (very near normal for mid August). Shortwave over
NE New Mexico sunrise Monday is expected to spread into SW KS
during the peak heating afternoon hours, rotating around the
subtropical anticyclone centered over the Arklatex. Scattered
thunderstorm development will favor the SE zones Monday
afternoon/evening. 12z NAM shows enhanced 0-3km EHI along the
convergence axis across the SE counties late Monday, and SPC`s
5% wind/hail probability for the SE zones is reasonable.
.LONG TERM...(Tuesday through Sunday)
Issued at 200 PM CDT Sun Aug 11 2019
Summer upper anticyclone centered over central Texas late Monday
will continue retrograding westward to near El Paso by late
Tuesday. All zones are forecast to remain dry daylight Tuesday,
given subsidence behind the departing shortwave. Light afternoon
easterly/upslope wind components will keep the heat at bay Tuesday,
with max temperatures only in the upper 80s and lower 90s.
Northwest flow aloft, around the El Paso ridge, will direct any
daily mountain convection southeastward into the western zones
(primarily west of US 283) Tuesday night, and the NBM pops reflect
this.
Temperatures on Wednesday will remain relatively mild for mid
August, as a central plains surface ridge will prevail, forcing
surface winds with an easterly component and preventing downslope.
Many locations should hold in the upper 80s Wednesday afternoon.
Again, daylight Wednesday should be mostly dry. 12z ECMWF suggests
another round of convection will impact the western zones late
Wednesday, in response to continued NW flow aloft around the
Desert SW ridge. NBM pops show this trend, but the slight rain
chances currently in the forecast for late Wednesday will likely
need to be raised with future forecasts. Appears to be a rather
classic NW flow convective pattern.
After Wednesday, the subtropical upper high weakens substantially,
squashed and compressed into Mexico, in response to a strong upper
trough in the Pacific NW Thursday, and passing through the
northern Rockies Friday and Saturday. This synoptic evolution will
force flow aloft to gradually become SWly, which is a warmer,
drier and windier pattern for SW KS. Expect afternoon temperatures
to gradually warm, south winds to increase, and rain chances to
largely end, Thursday through next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 505 PM CDT Sun Aug 11 2019
Isolated convective development is possible around the GCK-DDC-LBL
areas through this evening, but convective coverage will be
limited. As such, confidence on direct impacts on the airports is
low, and largely left out of the TAFs. Still expecting a large
complex of thunderstorms to pass just north of a Scott City-HYS
line during the 00-09z Mon time range. Some scattered convection
will likely occur near HYS tonight, with enough confidence for a
convective TEMPO group in the HYS TAF, but still feel strongest
impacts to aviation will pass north of HYS. A low level jet is
expected to increase to near 50 kts at 850 mb tonight, and
included LLWS in all TAFs around 06-09z Mon. A light NW wind shift
is expected behind a weak cold front through Monday morning. VFR
and scattered to broken mid clouds are expected daylight Monday,
with N/NE winds of 10-20 kts. Thunderstorm redevelopment is
expected along and south of a LBL-DDC line after 21z Mon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 72 92 66 91 / 20 30 30 10
GCK 66 92 62 90 / 20 20 20 0
EHA 67 93 63 91 / 20 20 20 10
LBL 70 94 65 92 / 20 20 20 10
HYS 69 91 66 88 / 50 10 20 0
P28 76 99 69 91 / 10 30 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJohnson
SHORT TERM...Turner
LONG TERM...Turner
AVIATION...Turner
Area Forecast Discussion
National Weather Service Duluth MN
1054 PM CDT Sun Aug 11 2019
.SHORT TERM...(This evening through Monday night)
Issued at 404 PM CDT Sun Aug 11 2019
A shallow cold front was located over our southern forecast area
this afternoon. A region of 925 and 850 mb convergence and
frontogenesis stretched from near Brainerd to just south of the
Twin Ports and east-northeast over western Lake Superior. This
region of forcing for ascent has supported isolated to scattered
showers during the past few hours. The latest runs of the HRRR and
HRRR Experimental seem to have a handle on the general flavor and
location of the showers. Convergence and FGEN decreases this
evening and think showers will diminish within an hour either side
of 7 PM. Lingering clouds and moisture over the Northland should
buoy temperatures with lows in the low 50s north to the upper 50s
and low 60s south.
A shortwave trough over Montana and Wyoming this afternoon will
ride northeastward across the Northern Plains tonight and into
western Minnesota by 12Z Monday morning. Light rain and possibly a
few rumbles of thunder are expected ahead of the trough and
should move into our western zones by late Monday morning. The
initial surge of precipitation may dissipate over northern
Minnesota by late afternoon while another surge of precipitation
moves into northwest Wisconsin. Rain shower and thunderstorm
chances increase overnight as a deeper trough moves into the
eastern Dakotas and western Minnesota. Highs Monday will trend a
little cooler with upper 60s and low 70s north and upper 70s
south. Lows Monday night will be in the low 50s north to the upper
50s south.
.LONG TERM...(Tuesday through Sunday)
Issued at 404 PM CDT Sun Aug 11 2019
A potent upper level shortwave will move across the area on
Tuesday and Tuesday evening, and have brought some likely pops to
parts of the area Tuesday morning, when confidence in the
precipitation is highest. With the surface low to our south, I
have limited the thunder to no more than chance, as we may not be
able to bring enough instability in for more widespread thunder.
Temperatures will be on the cool side, with highs in the upper 60s
to no more than mid 70s. Precipitation moves out by Tuesday
evening. The retreating clouds and drier airmass moving into the
area should allow temperatures to drop off to the mid 40s to low
50s, another cool night.
Wednesday should be a quiet with a weak ridge axis sliding across
the area. Some weak shortwaves may move across the area in the
Thursday-Friday time range with northwest flow aloft and a weak
baroclinic zone setting up over the area aloft. There is little
model agreement in the timing of such shortwaves though, and have
kept pops in the slight to low end chance pop range. Model
agreement only gets worse by Saturday, as some models shove a
fairly decent ridge axis and warm air into the area, but others
have a potent upper level shortwave moving across the area. Have
poor confidence in the forecast at this point, and have kept pops
low still, but I did allow temperatures to get warmer with highs
by Saturday back in the 70s and low 80s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 704 PM CDT Sun Aug 11 2019
What minimal shower activity there is will decrease this evening
affecting only KHYR for the first hour or so of the TAF period. A
system approaches Monday evening and will bring widespread shower
activity to the area. Fog shouldn`t be a problem tonight due to
drier air that has moved into the area from the north. There may
be a little patchy fog near KBRD and KHYR as the front stopped
near there allowing the moisture content of the air to be
relatively higher there.
&&
.MARINE...
Issued at 1028 PM CDT Sun Aug 11 2019
Not a whole lot happening on the marine side of the house, but
there will be an increase in northeasterly winds as a system
approaches which will increase winds near the head of the lakes
and wave heights as well.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 72 57 69 / 10 10 50 60
INL 51 71 53 74 / 0 50 50 30
BRD 59 74 57 70 / 20 30 50 40
HYR 57 77 57 72 / 30 20 50 50
ASX 55 71 57 72 / 0 10 40 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...Huyck
LONG TERM...LE
AVIATION...Wolfe
MARINE...Wolfe
Area Forecast Discussion
National Weather Service Quad Cities IA IL
620 PM CDT Sun Aug 11 2019
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 308 PM CDT Sun Aug 11 2019
Afternoon surface analysis shows a surface low in northern Iowa in
the vicinity of KMCW with a warm front stretching southeastward
towards KSQI and then southward to KPIA. The remains of a morning
MCS continued to dissipate as it moves eastward across southern
Iowa this afternoon. A cold front trailed the surface low to the
southeastward to KDSM to southeastern Nebraska. As of 3 PM
temperatures ranged from 76 degrees at KFEP to 84 degrees at KBRL,
KIIB, and KMPZ. Dewpoints were generally in the lower to mid 70s
across the area.
&&
.SHORT TERM...(This Evening through Tonight)
ISSUED AT 308 PM CDT Sun Aug 11 2019
Short term period is this afternoon and tonight. The main model
differences are between the Synoptic Models and CAMs. The main
forecast concerns are chances of precipitation.
The synoptic models are depicting the upper level support that
brought todays showers and thunderstorms lingering across the area
through 00 UTC Monday before shifting eastward along with the better
moisture. This would give us a dry forecast through 12 UTC
Monday. The Convective Allowing Models simulated radar
reflectivity continue to keep convection festering across the area
south of Interstate 80 into the evening hours. The current forecast
is a compromise between these two ideas. The best chances for
showers and storms will be south of a Fairfield to Galesburg line.
A marginal risk of severe thunderstorms remains in place across the
region. The main concern has been the risk of isolated damaging
winds. Satellite is depicting decrease clouds to the west which
could helps us to further destabilize late this afternoon and into
this evening. Brief periods of heavy downpours are possible with any
storms.
.LONG TERM...(Monday through Sunday)
ISSUED AT 308 PM CDT Sun Aug 11 2019
Monday
Overview: A quick moving shortwave impulse and MCS will propagate
from NE Colorado tonight to the Upper Mississippi Valley on Monday.
Latest indications are for the storm complex to weaken as it heads
into Iowa, outrunning the better LLJ convergence. With that said,
the HRRR maintains a strong line into the southwest Monday morning
before weakening it further. Leftover rain and embedded thunder can
then be expected from the late morning into the afternoon especially
across the northern two-thirds of the area.
Severe Thunderstorm Potential:
As surface-based instability rapidly increases through the mid to
late afternoon south of I-80, and a surface low approaches,
convective redevelopment is expected.
The Storm Prediction Center has an Enhanced risk for severe storms
over the south-central to southeast CWA, roughly southeast of a line
from Aledo, IL to Kahoka, MO. A Slight risk extends further to the
north and northwest. Best estimate on timing for severe storms is
between 3 to 10 PM. The primary risks are damaging winds, isolated
tornadoes, and localized flash flooding. Large hail is also possible
with discrete cells.
Moderate shear of 40-50 kts and high instability (2500-3500 J/kg of
SBCAPE) are supportive of a supercellular storm mode with storms
that redevelop during the afternoon/evening. Cold pool organization
should lead to upscale growth into a linear structure with potential
for enhanced wind damage in bowing segments later into the evening.
Some uncertainty as to where the MCS matures. It could occur in our
south and southeast, or focus more into central Illinois.
The atmosphere will become anomalously moist with PWATs near 2
inches, setting the stage for a county or two wide corridor of 1-3"
rainfall amounts. Models have been trending the heaviest rain axis
southward. The HREF members are in decent agreement hitting counties
south of I-80 and east of a Muscatine to Memphis, MO line with the
highest rain totals. The ground is very dry, but for areas that
receive hourly rain rates near 2", localized flash flooding is
possible with urban locations of greatest concern. Held off on a
Flash Flood Watch for now due to uncertainty on convective placement
and potential for training storms.
Uttech
Tuesday...There may be morning fog in heavy rainfall areas if north
sfc winds don`t increase in time. Will have to watch for northwest
flow system in the wake of the passing Monday wave to possibly
produce sctrd showers and storms in building afternoon instability
especially north of I80. But for now will limit POPs until more
confidence is attained.
Wednesday through Saturday...After a below normal temp Wednesday, re-
building thermal ridge upstream to the west will try to migrate
eastward and make for re-bounding temps by late week and next
weekend. In the process, still some chance for warm air advection
fueled storm clusters in or near the CWA especially at night for
portions of friday into Saturday. ..12..
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
ISSUED AT 616 PM CDT Sun Aug 11 2019
A chaotic mix of VFR and MVFR cigs will continue to trend towards
VFR this evening, with isolated storms possible, especially over
central Illinois. A storm is possible at any time during the next
24 hours, but we will focus our attention towards the late
afternoon hours Monday, as a wave of low pressure rides along a
front over the region. This should drive a strong area of storms
through the entire area, with some threat for damaging winds as
they arrive, especially along and south of Interstate 80 in Iowa
and Illinois during the afternoon and early evening Monday. Heavy
rain, low visibility and hail are also possible, but with this in
the extended period of the TAF, we have indicated an MVFR
condition in cigs and visibility, with high confidence of that
occurring, since we cannot yet identify the critical hours of
VLIFR in strong storms yet.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Cousins
SHORT TERM...Cousins
LONG TERM...Uttech/12
AVIATION...Ervin
Area Forecast Discussion
National Weather Service Green Bay WI
954 PM CDT Sun Aug 11 2019
New Information added to update section
.UPDATE...
Issued at 949 PM CDT Sun Aug 11 2019
Clearing has been more progressive this evening than expected, so
have made adjustments to sky cover for the rest of the night. Have
also added more fog overnight into Monday morning, and suspect
there will be areas of dense fog for the morning commute. Also
lowered min temperatures a few degrees.
&&
.SHORT TERM...Tonight and Monday
Issued at 323 PM CDT Sun Aug 11 2019
Primary forecast challenge through Monday will basically revolve
around cloud trends associated with weak and slow-moving weather
systems.
Low to mid-level clouds have been very stubborn today over most of
the forecast area. This has resulted in cooler daytime maximum
temperatures than forecast, except for the far north where more
sunshine has allowed temperatures to climb into the upper 70s near
the upper Michigan border. Clouds are the result of combination
of weak upper-level impulse moving across the state and weak low-
level thermal and moisture advection downstream of low-level
trough axis over western Wisconsin late this afternoon. RAP
soundings indicate that surface-based moist layer extends up to
about 850 mb. Latest satellite trends indicate considerable cloud
cover extending westward into southern Minnesota and all of Iowa,
thus not especially optimistic to see much clearing over central
and east central Wisconsin this evening and overnight. However
some improvement has been seen last few hours north of Highway 8
where slightly drier air and a bit more mixing is occurring. HRRR
and HREF also continue to suggest that perhaps a few showers could
still pop-up over mainly the far northeast portion of the state
ahead of aforementioned weak upper-level impulse and weak surface
frontal boundary dropping southward from Upper Michigan. Kept low-
end chance pops going mainly north and east of GRB into the early
evening as per previous forecast.
Overnight as surface trough slowly sags southeast of the forecast
area, winds will begin to turn northeast with generally modest
northeasterly flow setting up over east and eastcentral sections
of the forecast area by Monday morning. Given residual boundary
layer moisture will still be in place Monday morning, anticipate
stubborn low clouds to persist well into the morning especially
over the lakeshore and Fox Valley. Could also be some fog
especially central and north with light winds and deep boundary
layer moisture. HREF ensemble mean surface dewpoints and winds
suggest a somewhat better push of drier air from the northeast, may
commence sometime during the afternoon on Monday allowing for a
bit more sunshine especially over the northeast third of the
state. Expect more clouds to persist over southern and southwest
portions of the forecast area closer to the next upstream
shortwave impulse forecast to impact mainly northern Illinois into
perhaps far southern Wisconsin Monday afternoon. Highs on Monday
will generally be in the middle 70s most areas with cooler
readings along the lakeshore with northeast boundary layer winds
expected.
.LONG TERM...Monday Night Through Sunday
Issued at 323 PM CDT Sun Aug 11 2019
The medium range models have trended further south with the synoptic
scale system Monday night and Tuesday. This track would result in
a lower chance of showers and thunderstorms and less threat of
northeast winds capable of producing shoreline flooding.
Upper flow is forecast to become northwest Tuesday night through
the end of the week. Slightly cooler than normal temperatures are
expected Wednesday and Thursday as high pressure moves from the
northern Plains to the Great Lakes.
Heights rise later in the week, and low level winds turn to the
south as the surface high moves off to the east. High temperatures
could be 5 to 10 degrees above normal by Saturday with increased
chances of thunderstorms as a slow moving cold front approaches
from the west.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 638 PM CDT Sun Aug 11 2019
There are several questions with the forecast this evening,
including how far south the clearing associated with a weak cold
frontal boundary will advance, how low ceilings will drop to
overnight into early Monday, and where fog will develop.
Clearing over northern WI has been slowly but steadily advancing
south this afternoon. However, suspect that the clearing will
stall after sunset, as the boundary layer starts to cool. With
this in mind, will not forecast any clearing at the southern TAF
sites, even though the back edge of the clouds has already
progressed to a RRL-MNM line. Will be watching satellite trends
closely during the early to mid evening.
Assuming that clouds linger over all but the RHI TAF site, would
expect that ceilings will steadily lower overnight, dropping to
MVFR at most locations, and IFR locally. Some light fog may also
occur.
Farther north, where clearing has already occurred, the main
concern will be fog development, as winds will remain light. Could
see IFR/LIFR vsbys at RHI late tonight, as well as at several
other airport sites in north central WI.
Daytime heating on Monday should allow ceilings to gradually rise
again during the day, with VFR conditions possible by mid to late
afternoon at the southern TAF sites. A few showers could approach
AUW/CWA late in the day.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........Kieckbusch
SHORT TERM.....ESB
LONG TERM......RDM
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1033 PM EDT Sun Aug 11 2019
.SYNOPSIS...
Rainfall chances will slowly increase during the first half of the
week, peaking on Wednesday with a weak cold front and remaining
higher than normal into the weekend. Hot and humid conditions will
persist through mid week, with a cooling trend toward the end of the
week.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 1030 PM EDT Sunday: All late evening PoPs have been pulled
from the southern Appalachians as profiles have stabilized.
Attention will now turn to a gradually improving easterly fetch of
moisture in the 950 to 850 mb layer, and weak upglide developing
overhead as mid-level vorticity lobes start arriving from the
northwest through the early morning hours. Will thus bring back
isolated shower chances along the eastern escarpment of the
mountains through daybreak. Stratus should also fan out in areas
away from the escarpment to provide developing cloud cover and keep
mins mostly in the lower 70s east of the mountains. Another round of
mountain river valley fog and low stratus is expected to form before
the upglide induced clouds get started in earnest.
On Monday, the low clouds in the morning may produce a late start on
our warmup, which should keep the Heat Index from getting out of the
90s in all but a few parts of the Lakelands where the dewpoint will
be highest. Think only the mtns will have a real chance of seeing
any deep convection as a weak short wave moves in during the
afternoon. East of the mtns, a lingering capping inversion should be
enough of a limiting factor to keep the precip chances at bay.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 230 PM Sunday: The longstanding upper ridge to our west
will break down Monday night, and the pattern looks to remain
quasi-zonal thru Tuesday. Nonetheless, 500mb heights will be similar
if not slightly higher Tue compared to Mon, while 1000-850mb
thickness peaks for the period. Dewpoints will remain elevated
as low-level southerly flow regime continues. Combining temp and
dewpoint guidance that has performed well recently, heat index is
expected to rise above 100 throughout the Piedmont Tue aftn, with
a smattering of locations pushing past 105 (generally due to local
effects keeping dewpoints higher). We could make the argument that a
Heat Advisory will be needed for Tuesday if guidance trends hold up.
A cold front will extend from the Northeast to the Mid-South on
Tuesday, in conjunction with a trough developing over the eastern
CONUS and another deep ridge beginning to build over the Desert
Southwest. Large instability is expected over the Ohio Valley
ahead of the front, and some of the convection that develops
there may propagate across the Appalachians into our area Tuesday
night, along with the front. Confidence in the overnight PoPs is
limited by differing model depictions of that activity and how much
stabilization occurs in its wake. At any rate, the front is expected
to remain in our vicinity through Wednesday, enhancing coverage of
diurnal showers/storms across the Piedmont in conjunction with a
weak shortwave embedded in the upper trough. The presence of these
features implies storms may continue into Wed night. The height
falls aloft along with additional cloud cover suggest max temps
will trend downward slightly on Wed, though soupy dewpoints still
are expected. Heat indices most likely will top out between 100
and 105.
Regarding severe wx chances Tuesday, given the sweltering sfc
conditions, we will have large sfc-midlevel theta-e lapses despite
PWAT values near 2 inches. Shear will be on the gradual increase,
so the earlier diurnal activity may be more of a pulsey nature,
with multicells becoming increasingly likely as the day continues
and also if activity propagates in from the west overnight. SPC has
a portion of our area in the Day 3 marginal risk. The ingredients
for severe weather on Wednesday are not all that different, but
better shear will be available throughout the day, so clusters of
storms near the frontal boundary may pose a wind and hail threat.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 2 PM EDT Sunday: Starting Thursday morning with a dip in the
jet stream as you may see an axis roughly from the Great Lakes to
the Florida Panhandle. There will be a ridge over the SE States and
from Bermuda eastward. The weak surface cold front will drift south
of our area as waves of low pressure move along the front from the
Gulf. The ECMWF is trending wetter toward the end of the week for
the Deep South compared to yesterday. The EC has an apparent
tropical low forming on Thursday and Friday then coming onshore near
Pensacola to start the weekend. The EC has this feature over
Tennessee Sunday night then turns it east toward the NC mountains.
No need to get overly concerned since that is a week away and lots
can change. The GFS on the other hand pushes the front down over
Florida and brings somewhat drier air to our region. The models are
in agreement that the SW ridge builds east at least briefly toward
the end of the weekend. A strong northern shortwave approaches next
week. Will have to wait to see how that pans out. Temperatures near
normal for Mins and below by 3 to 5 degrees for Maxes Friday through
the weekend.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: The early part of the overnight hours will
see mainly FEW to SCT lingering stratocumulus with SCT to BKN
cirrus. The main impact will be the potential for low clouds before
daybreak, both from mountain valley fog and stratus and from
Atlantic moisture advancing west into the terminal forecast area.
The mountain valley fog/stratus seems a bit more certain, although
even that could be affected by weak upglide producing higher stratus
in the MVFR range. For the foothill and piedmont sites, the LAMP MOS
has trended much more pessimistic, with solid IFR to LIFR cigs
developing overnight and persisting into Monday morning. The RAP
profiles have not had as much run-to-run consistency and advancing
stratus could provide ceilings anywhere in the IFR to VFR range. The
best compromise will be to feature mainly a daybreak window of low-
end MVFR cigs at the foothill sites and KCLT, and keep the solid IFR
to LIFR conditions confined to the mountain valleys and KAVL for
now. Anticipate light ENE winds becoming a bit more SE then
southerly with time. Conditions should scatter out to VFR at some
point Monday afternoon throughout, with PROB for TSRA being
reintroduced at KAVL only.
Outlook: Coverage of showers and thunderstorms will increase Tuesday
into Wednesday as a cold front and associated moisture/forcing
arrive from the northwest. The boundary will stall southeast of the
area mid to late week, with lower end convective chances persisting.
Early fog/stratus will be possible each day across mountain valleys.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% Med 78% High 90% High 100%
KAVL High 100% Low 45% High 87% High 100%
KHKY High 100% High 93% High 81% High 100%
KGMU High 100% High 80% High 84% High 100%
KAND High 100% Med 71% High 97% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...HG/PM
SHORT TERM...Wimberley
LONG TERM...DEO
AVIATION...HG
Area Forecast Discussion
National Weather Service Spokane WA
552 PM PDT Sun Aug 11 2019
.SYNOPSIS...
Showers with embedded thunderstorms will cross Eastern
Washington and the Idaho Panhandle into the evening. A few
strong thunderstorms will be possible over the Northeast
Mountains and in the Northern Panhandle with heavy
rain being the primary concern. The shower threat
retreats to mainly the mountains through the middle of
the week, with another storm system expected around Thursday.
Temperatures are expected to remain on the cool side of
normal.
&&
.DISCUSSION...
Early evening update: Made some adjustments to the evening POP`s
based on radar trends and latest HRRR model runs. A cluster of
showers and thunderstorms between Wilbur and Hunters has produced
an outflow boundary with showers and isolated thunderstorms
on the increase in Lincoln county. HRRR shows this activity will
continue to develop and move east into the Spokane and Coeur
d`Alene areas early this evening. With the Spokane 00z sounding
showing around 900 J/KG of CAPE this idea is accepted and thus
have increased POP`s for this evening. Another area of showers
between Republic and Northport will head east this evening as well
towards Ione, Sandpoint, and Bonners Ferry. Meanwhile from Moses
Lake to Pullman and points south there is very little activity on
radar and thus have adjusted POP`s down in these areas, as well as
along the East Slopes of the Cascades where downslope west winds
will keep the remainder of the evening dry around places like
Winthrop, Chelan, and Wenatchee. JW
&&
.AVIATION...
00Z TAFS: Showers and thunderstorms around the Spokane and Coeur
d`Alene area should be moving out around 02-04z as a low pressure
system pulls away from the area. At this time storms are expected
to be isolated so have not mentioned thunderstorms in the TAF`s
but will be watching the radar closely for possible amendments.
VFR conditions are expected this evening except under heavier
showers and thunderstorms where conditions may briefly deteoriate
to MVFR. Overnight models show the boundary layer saturating in
the Idaho Panhandle with MVFR stratus expected to develop at KCOE
by early morning. There is a small chance these CIGS could briefly
develop at KGEG/KSFF as well. Otherwise drier weather is expected
Monday with VFR conditions. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 51 76 51 82 55 82 / 70 0 0 0 0 0
Coeur d`Alene 52 75 49 80 53 81 / 90 0 0 0 0 0
Pullman 48 76 46 80 50 80 / 20 0 0 0 0 0
Lewiston 57 83 57 88 62 87 / 10 0 0 0 0 0
Colville 45 81 43 85 45 87 / 80 0 0 0 0 10
Sandpoint 50 73 47 79 49 79 / 60 10 10 0 0 10
Kellogg 53 72 53 79 56 79 / 60 0 0 0 0 0
Moses Lake 55 81 52 86 56 87 / 0 0 0 0 0 0
Wenatchee 60 81 61 84 63 84 / 0 0 0 0 0 0
Omak 58 82 57 85 59 86 / 10 0 0 0 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Riverton WY
200 PM MDT Sun Aug 11 2019
.SHORT TERM...(This evening through Monday)
An early show of elevated convection has already taking place
across the western half of the CWA in the form of innocuous
shower activity. this loosely held band of showers is progressing
east and at the time of this writing extends from Johnson County,
down through Natrona County, Southeast Fremont County, and into
Eastern Sweetwater County. Higher capes are beginning to pool
across Johnson County. The HRRR is suggesting a fresh round of sfc
based convection to get firing along and north of the Owl Creek
Mtns and along and east of the Casper Arch (The Natrona/Fremont
County line). Some other thunderstorms have formed over Eastern
Sweetwater County. Weaker showers have formed over Western
Sweetwater County which seems to mark the beginning of the cool
front. The RH at RKS is currently 37 percent, KMM is 14 percent,
and farther west, Evanston is down to 12 percent. KMM and Evanston
are blowing out of the southwest at 29 and 28 knots respectively,
so this is indeed the true dry punch. The other initial dry line
sfc boundary will become established behind the anticipated
potentially strong thunderstorms in Johnson County where a slight
risk of svr is indicated, just behind the Gulf moisture feed. This
dry feed moving in from the southwest will continue to nose in
across the rest of the CWA with a resulting stabilizing of the
environment and dropping RH values. Winds will calm down by 8 pm
this evening.
Sunday will feature slightly cooler temps and drier air along with
breezy west winds behind the front/shortwave and under a westerly
confluent steering flow.
.LONG TERM...(Monday night through Sunday)
Once today`s trough passes through the region, the flow will
flatten out, with dry zonal flow continuing into the latter half
of the week. Minimal to no rain chances expected through
Wednesday, with temperatures gradually returning into the 80s and
90s. Next fluctuation starts to affecting the region Thursday as a
trough dives into the Pacific northwest. While this added
instability would mean a sharp increase in rain chances, the lower
elevations will still be dry, so convection will be limited to to
the higher elevations of north Wyoming, especially Thursday and
Friday. The trough passes by to the north on Saturday, bringing an
end to any further rain chances.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Area of showers and thunderstorms continues to move across the
Wind River basin and south Wyoming, dropping a brief shower at
KRIW and KRKS in the past hour. This area is moving to the
northeast, and should move across the KCPR area later this
afternoon. Most areas west of the divide and in the Big Horn basin
are already clearing out, and likely won`t see any more shower
activity today. Remaining showers are expected to move quickly
northeast this afternoon, with quickly clearing skies. All areas
will see light and variable winds tonight under mostly clear
skies.
&&
.FIRE WEATHER...
|...Red Flag Warnings in effect this afternoon and evening for
zones 283 and 288...
...Red Flag Warning in effect this afternoon and evening and
Monday afternoon and evening for zone 280...
...Rangeland Fire Danger Statement this afternoon and evening for
zones 277, 278 and 279...
A "dry line" is expected to become established across our northern
and northeast zones. Ahead of this line, strong, to possibly
severe thunderstorms will occur this afternoon. A cold front is
also currently moving across far Western Wyoming where the RH is
already down in the low teens behind the front across Southwest
Wyoming. other scattered thunderstorms will occur this afternoon,
mainly from zone 281 to the far eastern portions of 279. Storms
will mainly end across the area from southwest to northeast early
this evening. Relative humidity values will quickly drop behind
the front from west to east, becoming critical in the Wind River
Basin and the southern zones. Gusty winds up to 35 mph will occur
over the southern zones behind the front.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 4 PM this afternoon to 7 PM MDT Monday for
WYZ280.
Red Flag Warning until 8 PM MDT this evening for WYZ283-288.
&&
$$
SHORT TERM...Lipson
LONG TERM...Straub
AVIATION...Straub
FIRE WEATHER...Lipson
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Monday)
Issued at 324 PM CDT Sun Aug 11 2019
Another round of thunderstorms is looking likely tonight, mainly
near the KS/NE state border, as a robust midlevel shortwave develops
over the Colorado Rockies and lifts northeast into Nebraska. Storms
have developed in eastern CO and will track east/northeast
tonight. The ascent associated with the shortwave, enhanced by a
LLJ late tonight will interact with a moist and buoyant airmass.
The RAP and HRRR models have around 3000 J/Kg of MLCAPE in
northeast KS tonight, and bulk shear values could be 35 to 40 kts
as storms approach. Given those parameters, storms are more likely
to stay organized and maintain strength. Severe thunderstorms
will be possible, with 60 to 70 mph wind gusts being the most
likely hazard. Additionally, Pwats are expected to remain around
2.0 inches, so heavy rainfall is likely with thunderstorms
tonight. Flash flood guidance is lower following rainfall from
last night. Thus, have decided to include Cloud, Republic and
Washington Counties is a Flash Flood Watch during the overnight
hours. Current QPF is for a general one to two inches of rain, but
locally higher amounts will be possible, and rainfall is expected
to accumulate quickly given the moisture content of the airmass
and the expected strength of storms. Storms should quickly exit
the area early tomorrow morning.
The daytime hours of tomorrow are expected to be dry. The front in
southerly Nebraska will sag southward into, and eventually move
through, the CWA as the surface low works into northern MO/southern
IA. Prefrontal compression, along with reduced mixing and higher
dew points ahead of the front will make for a hot and humid day,
especially along and south of Interstate 70. As such, a Heat
Advisory will be in effect across east-central KS during the
afternoon and evening hours with heat index values forecast to be
between 105 and 110 degrees.
.LONG TERM...(Monday night through Sunday)
Issued at 324 PM CDT Sun Aug 11 2019
Transitioning into the extended period, the key points are: a brief
cool down followed by a gradual warmup with intermittent rain
chances through the period.
By Tuesday evening the surface cold front responsible for tonight`s
and tomorrow`s thunderstorm activity will progress southeast of the
forecast area, ushering slightly cooler and drier air Tuesday into
Wednesday. A few showers/storms are possible as it departs late
tomorrow night into early Tuesday, although this potential is small.
Weak surface ridging behind the aforementioned front combined with
wet soil conditions could poise a fog potential Wednesday morning.
Temperatures look to remain quite seasonable for mid-August as the
midlevel ridge axis amplifies across the Southwestern US. Afternoon
highs look to remain in the 80s Tuesday through Thursday.
The aforementioned midlevel ridge will overspread the High Plains
late Thursday into Friday. As a result, the surface ridge axis will
progress eastward allowing WAA to overspread the CWA on it`s western
periphery. Showers and thunderstorms are possible late Thursday into
Friday on the nose of a strong LLJ. Precipitation coverage could be
enhanced by a shortwave trough translating through the midlevel
flow.
Temperatures will continue to warm through the weekend as the
midlevel ridge axis overspreads the area, surging temperatures into
the 90s Friday-Sunday. A deep midlevel trough is progged to come
ashore in the Pacific Northwest, transitioning the Central US to
southwesterly midlevel flow. Showers and storms are possible late
next weekend as the aforementioned midlevel trough ejects across the
Northern Plains, shunting a surface front through the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 634 PM CDT Sun Aug 11 2019
For the 00z TAFs, main focus is on the potential for a line of
thunderstorms to track over the TAF sites overnight into Monday
morning. The best chances for storms will be along the KS/NE
border with some model uncertainty in just how far south these
storms may extend. As a result, only have VCTS mentioned at this
time. If storms track over the TAF sites, gusty winds will be
possible at upwards of 25-35kts. VFR conditions are likely for the
remainder of the TAF period. There is a chance for some scattered
storms to develop late Monday afternoon/evening with a frontal
passage, but confidence is too low in the timing/tracking of these
potential storms to warrant a mention in the TAFs at this time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for KSZ054-058-059.
Heat Advisory from 1 PM to 8 PM CDT Monday for KSZ026-039-040-
054>056-058-059.
Flash Flood Watch from 11 PM CDT this evening through Monday
morning for KSZ008-009-020.
&&
$$
SYNOPSIS...Teefey
SHORT TERM...Teefey
LONG TERM...Baerg
AVIATION...Hennecke