Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/08/19
Area Forecast Discussion
National Weather Service Birmingham AL
725 PM CDT Wed Aug 7 2019
.UPDATE...
Evening Update and 00Z Aviation.
&&
.SHORT TERM...
/Updated at 0717 PM CDT Wed Aug 07 2019/
Bulk Shear values have not held on and have actually fallen
slightly past few hours. Therefore, the outflow has been out-
running the storms in several spots. But there are some locations
where the storms are hanging close to the boundary and some cold
pooling is taking place. Will keep the risk areas the same for now
with the best chance north of I-59. Went ahead an increased pops
north and east as the east southeast motion will continue.
Confidence wanes after a few hours as the southern extent is
questionable with loss of heating and no large cold pool noted.
75
Previous short-term discussion:
/Updated at 0353 PM CDT Wed Aug 07 2019/
We will be upgrading the severe thunderstorm potential into the
Slight Risk for parts of northwest and north central areas. This
will cover our northwest counties into northern Jefferson and
Blount Counties. Confidence is slightly less for the northeast
counties but are monitoring the upstream tends closely. See the
web page threat graphic for specifics.
Upstream convection is now starting to organize itself a bit
better. The main challenge is how far south the strong to severe
storms will translate. There is a strong mean moisture gradient
between the Tennessee Valley and Central Alabama at this time,
with 2+ inches north to 1.6-1.7 in Central Alabama. It appears
that vertical motion and the cold pool will push southward enough
to get storms into northern areas. SBCAPES are in the 4000 range
with DCAPE in the 1300 neighborhood per latest RUC analysis. The
surface dew points have not mixed out this afternoon and remain in
the 70s north. The highest confidence is that the storms organize
in southwest Tennessee and migrate into Central Alabama late this
afternoon into early evening. Much of the latest model data is
not handling all the parameters and subsequent qpf correctly. The
threats with the strongest storms will be damaging wind gusts of
60-65 mph and quarter size hail. Rainfall may be heavy at times
under the strongest cores. Will also adjust pops higher in these
zones.
75
Previous short-term discussion:
/Updated at 1230 PM CDT Wed Aug 07 2019/
Today and Tonight.
Radar has been rain free since 8 am this morning. Temperatures
have warmed quickly in the westerly low level flow regime. Several
sites already in the lower 90s. Most areas along and south of
I-85 and west of I-65 will see highs in the middle 90s, with heat
indices 101-104 degrees. The outflow boundary from last nights
convection is showing up on visible satellite imagery with
cumulus developing mainly south of a Vernon to Jasper line. A
majority of the hi-res models have been showing convective
initiation across northeast MS and NW Alabama by 2-3 pm this
afternoon, and will continue with highest rain chances in this
area. With surface temperatures in the mid 90s and dewpoints in
the lower 70s, surface based CAPE will rise to 4000-4500 J/kg.
DCAPE values also running on the high side north of I-20 due to
drier air loft, with values near 1300 J/kg. Bulk shear of 30-35
knots will be sufficient for storms to become organized into a
line segments. Any storm this afternoon has the potential for
strong wind gusts, but northwest Alabama will have the higher
potential for damaging winds. Stronger convection will propagate
southeast towards the Tuscaloosa-Birmingham corridor by the early
evening hours.
58/rose
.LONG TERM...
/Updated at 0336 AM CDT Wed Aug 07 2019/
Thursday through Tuesday.
Northwest flow aloft remains the forecast challenge through this
period, between a trough over eastern Canada and the northeastern
CONUS with an embedded deep upper low near Hudson Bay, and a
subtropical ridge stretching from the southern High Plains to the
Gulf. The ridge will try to continue to build eastward through the
period as the synoptic trough lifts out, but various convectively
enhanced shortwave disturbances rotating around the ridge will
attempt to impede its progress as they feed off a very moist air
mass and frontal zone. This will result in hot and humid
conditions punctuated by difficult to time areas of
thunderstorms/MCSs. On Thursday, it appears Central Alabama will
be under shortwave ridging between waves for much of the day. An
area of dry air aloft associated with the first cold front moving
through the East Coast states will also slide south across at
least the eastern half of the state, but moisture will be quickly
returning from the west in its wake ahead of the next front.
Overall the shortwave ridging aloft and drier air moving through
should limit the overall coverage of convection during the day on
Thursday, though the front and any other leftover boundaries could
serve as lifting mechanisms for convection. Will keep PoPs mainly
in the widely scattered category until boundary placement becomes
clearer. With plenty of SBCAPE and DCAPE and some mid-level flow,
an isolated strong to severe storm will be possible but any
details are unclear. With less coverage of convection expected and
rising heights, highs will reach the mid to perhaps upper 90s.
There will be a southwest to northeast gradient in dew points
caused by mixing down of dry air aloft behind the front, so areas
in the southern and western counties will have the best chances of
reaching heat advisory criteria.
Another shortwave may approach from the northwest late Thursday
afternoon/Thursday night. Long range CAMs are not showing much in
the way of MCS development, so kept PoPs on the lower end, but
trends will be monitored. Moving into Friday, PWATs increase above
2 inches as moisture pools ahead of another cold front. There
will likely be one or more MCSs across the Southeastern CONUS
during this period but details remain murky. Warming mid-level
temperatures will limit overall storm strength but locally heavy
rainfall may be possible due to the high PWATs. Areas in the
southern counties will have the best potential to see heat indices
reach 105 degrees ahead of any possible storms, and will add a
mention of this to the HWO for Friday. The ECMWF is more
aggressive than other guidance in bringing in a drier (but still
hot) air mass behind the front this weekend. Its ensemble members
show some spread in QPF, so only tapered off PoPs slightly in the
northeast counties. Will hold off on mentioning heat impacts in
the HWO for the weekend given this uncertainty. The ridge will
remain centered just off to our west for Monday and Tuesday, but
continued disturbances in the northwest flow will result in
chances of showers and storms. The potential for MCS cold pools
decreases confidence in the heat index forecast somewhat, but the
placement of the ridge and mid 70s dew points warrants adding in
at least a low confidence mention of heat impacts to the HWO.
32/Davis
&&
.AVIATION...
00Z TAF Discussion.
Showers and thunderstorms have been on the increase the past few
hours north of all the terminals. These storms will approach
BHM/ASN/ANB in the next hour or less. Mentioned VCTS and -SHRA at
these sites. Otherwise, expect some sct/bkn cumulus and cirrus
ceilings the next several hours north and east. Winds out of the
northwest and west should eventually lighten up. Winds pick back
up after 15z to 5-10 kts out of the west and northwest on
Thursday. At this time, mentioned Prob30 for thunderstorms at all
sites Thursday afternoon.
75
&&
.FIRE WEATHER...
Ongoing showers and storms may linger into this morning, with
additional development of showers and thunderstorms by this
afternoon. On and off shower and thunderstorms chances continue
Friday and Saturday. No critical fire weather conditions are
anticipated due to a humid air mass.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 69 94 71 91 70 / 70 30 30 50 30
Anniston 71 94 73 91 72 / 50 30 20 50 30
Birmingham 74 96 75 93 75 / 50 30 30 50 30
Tuscaloosa 74 97 75 93 75 / 40 30 20 50 30
Calera 72 96 73 92 73 / 40 30 20 40 30
Auburn 73 93 74 92 74 / 30 30 10 40 30
Montgomery 75 97 75 95 75 / 20 30 10 40 30
Troy 73 95 73 94 73 / 20 30 10 40 20
&&
.BMX WATCHES/WARNINGS/ADVISORIES/...
None.
&&
$$
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1149 PM EDT Wed Aug 7 2019
.AVIATION...
The cluster of showers and thunderstorms now extending from west
central Lower Mi into Wisconsin have been building south into the
better low level moisture influx. While the higher intensity
thunderstorms will likely remain southwest of the area, the overall
cluster of showers will continue to advance across Se Mi during the
early morning hours. The weak instability across Se Mi will however
support a decrease in both the coverage and intensity of the
showers/thunderstorms. Once the cluster of showers and a sfc cold
front the terminals early Thurs morning, latest model soundings do
suggest a period (perhaps brief) of MVFR stratus development
around/shortly after daybreak. Cloud bases will then lift during the
day with the diurnal growth of the boundary layer.
For DTW...Due to the lack of instability over metro Detroit, the
expectation is that the coverage of thunderstorms will decrease as
the upstream shower/thunderstorm complex approaches metro Detroit
tonight (07 to 11Z time frame). Upstream radar does support carrying
at least a TEMPO for showers early Thus morning.
.DTW THRESHOLD PROBABILITIES...
* Moderate for ceiling 5000 ft or less Thursday morning.
* Low for thunderstorms Thursday morning.
&&
.PREV DISCUSSION...
Issued at 847 PM EDT Wed Aug 7 2019
UPDATE...
Mid level water vapor imagery indicates at least a couple smaller
scale short wave impulses embedded within the convective complex now
stretching from central Wisconsin into west-central Lower Mi. These
short waves will track across northern Lower Mi tonight and will
invoke mid level height falls across Se Mi, mainly across the Saginaw
Valley and thumb region. These will also force a sfc cold front into
Se Mi. Strong low level inflow on the southern edge of this
convective complex will drive a narrow ribbon of high low-mid level
theta e air across the forecast area during the overnight, along/in
advance of the sfc front. This will support scattered to numerous
showers across the area. The duration of these showers will likely be
brief (especially in locals south of the I-69 corridor) given the
shorter duration of forcing and moisture. Weaker instability across
the forecast area still suggests an overall decreasing trend as the
upstream convection works its way east, which will limit the coverage
of thunderstorms. In light of upstream radar and the latest HRRR and
RAP, precip chances will be nudged upward a little bit tonight.
Otherwise, no major updates will be made to the current forecast.
PREV DISCUSSION...
Issued at 335 PM EDT Wed Aug 7 2019
DISCUSSION...
Elongated cold front extending from northwest Ontario into northeast
Wisconsin transitions to more of a zonally oriented stationary
boundary from northern Wisconsin to the Front Range of eastern
Montana. Thunderstorms are currently developing along the portion of
the front oriented orthogonal to the mean flow where convergence is
maximized. A packet of jet energy embedded within the periphery the
aggregate Hudson Bay low will result in a short-lived amplification
of the flow as it races through the Great Lakes region tonight. As a
result, the aforementioned frontal zone will pick up steam this
evening and is progged to move through the CWA between about 06-12z
Thursday morning. Very short-lived right entrance support over the
northern portion of the forecast area warrants higher pops there as
the integrity of forcing along the front is more certain. Loss of
dynamic support and meaningful convergence with southward extent
likewise supports a transition to chance pops. Altogether, nothing
more than an hour or two of rain, isolated thunder, at any given
location late tonight into early Thurs.
Cold advection supported by deep layer WNW cyclonic flow aloft will
ensue within increasingly well-mixed westerly flow. A high coverage
of diurnal stratocu will thin through the day as boundary layer
growth compromises moisture depth, although a few isolated showers
north of M59 will be possible as energy pivots around the upper low.
Otherwise, highs in the low 80s will be accompanied by light wind
gusts up to 20 mph or so. Canadian airmass fully entrenched by
Friday as H85 temps fall into the single digits. Although highs will
likely still approach 80 degrees courtesy of a healthy mixed layer,
dewpoints solidly in the low 50s and wind gusts around 15 to perhaps
20 mph will yield a definitive late-summer feel.
The upper level trough that has been locked over the James Bay
slides east further into Quebec as a low amplitude ridge builds
across the Plains and expands over Michigan Saturday. This will
allow for a dry weekend with comfortable/near normal temperatures.
Overnight minimums stand the best chance of deviating from outgoing
forecast, and would favor cooler values. Later Monday into Tuesday a
warm front lifts into the western Great Lakes quickly followed by a
weak cold front. These successive fronts bring a chance of showers
and thunderstorms for southeastern Michigan Monday evening through
the late evening period Tuesday.
MARINE...
The marine forecast is centered around a moderate cold front moving
across the central Great Lakes tonight. Bands and clusters of
thunderstorms ongoing along and ahead of the front will weaken while
moving eastward due to the loss of daytime peak heating, however
complete dissipation is not expected as the associated wave of low
pressure is capable of supporting activity through the night. The
showers and storms produce locally higher wind and waves within
southwest background flow ahead of the front. The northwest wind
shift is gradual but wind speed does pick up behind the front,
especially over the open waters of northern and central Lake Huron
where gusts could reach 25 knots Thursday afternoon and evening.
Both the southwest and northwest wind patterns remain below advisory
threshold farther south across St Clair and western Erie. Light to
moderate westerly wind then continues into Friday before high
pressure builds into the region this weekend.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....SC
UPDATE.......SC
DISCUSSION...JVC/KDK
MARINE.......BT
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Green Bay WI
651 PM CDT Wed Aug 7 2019
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Thursday
Issued at 157 PM CDT Wed Aug 7 2019
The latest RAP analysis and satellite/radar imagery show a cold
front moving to the southeast over far northwest Wisconsin early
this afternoon. A few storms popped over northern WI by late
morning, in a region of low level moisture convergence, and
quickly became near severe. Instability has been slowly growing
ahead of the front, with mixed layer capes exceeding 1200 j/kg.
Effective shears are highest over western WI, but 25 to 30 kts of
deep layer shear will be supportive of strong to severe storms
developing along the front this afternoon. High resolution
guidance indicates thunderstorms growing upscale across north-
central initially, before spreading southeast into the Fox Valley
around 5-6 pm. Damaging winds and large hail will be the main
threats with the strongest storms. Forecast concerns mainly
revolve around the severe thunderstorm threat into this evening.
Tonight...The cold front will be moving southeast across northeast
WI in the evening, exiting over northern Lake Michigan and
southern WI around 10 pm. Instability will be weakening rather
quickly after around 7 pm, so think the threats from the strongest
storms will mainly become strong damaging winds over northeast WI
until the storms exit. Clouds will decrease thereafter, as
northwest winds gradually push in cooler and drier air. Lows
ranging from near 50 in the northwoods to the low 60s over east-
central WI.
Thursday...The region will be on the southern periphery of
troughing centered over northern Ontario. Models project ample dry
air in the mid to upper levels, with an inversion present in the
800-700mb layer. Should have enough moisture in the low levels
after the recent rains for some flat fair weather cu popping with
the heat of the day. Cooler highs ranging through the 70s.
.LONG TERM...Thursday Night Through Wednesday
Issued at 157 PM CDT Wed Aug 7 2019
Dry conditions are expected Thursday night through Friday night as
surface high pressure slides across the Great Lakes and upper
ridging works into the northern Plains. Mostly clear skies, a dry
air mass and light winds will provide for a couple cool nights,
especially in the typical cold spots of central and north central
WI, where 40s are expected. Mostly sunny skies are expected on
Friday with highs in the 70s to around 80, which is slightly below
normal for this time of year.
Dry weather should continue into Saturday morning as the surface
high will slide east of the region. By Saturday afternoon, weak
pieces of shortwave energy will move from the northern Plains into
the Great Lakes. Still some uncertainty on location and timing as
these features are tough to pin down, especially this far out.
Chance or slight chance POPs seems reasonable from Saturday
afternoon/evening into Sunday morning. Model disagreement
continues from Sunday into early next week, with the
location/timing of shortwaves, boundaries, and possible complexes
of storms. Overall, temps look to be near or slightly below normal
through the period.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 651 PM CDT Wed Aug 7 2019
Widespread showers and thunderstorms will continue through around
02Z/03Z before ending from the northwest. Some of these could
remain strong or severe before winding down by mid to late
evening. Winds will shift to the west and northwest behind a cold
front by early evening . Good flying weather is expected
thereafter with relatively light winds and fair weather clouds
popping across the area by late Wednesday morning.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Lakeshore Flood Advisory until 9 PM CDT this evening for WIZ039.
&&
$$
SHORT TERM.....MPC
LONG TERM......Bersch
AVIATION.......Cooley
Area Forecast Discussion
National Weather Service Grand Rapids MI
1001 PM EDT Wed Aug 7 2019
LATEST UPDATE...
Mesoscale Discussion
.MESOSCALE DISCUSSION...
Issued at 1002 PM EDT Wed Aug 7 2019
Looking at the latest water vapor image loops it is clear there is
a significant amount of upper level divergence over eastern Lake
Michigan. The northern stream is aimed at Lake Superior while the
southern stream diverges into Indiana. This will continue to
support a low level jet core that will remain over central Lake
Michigan over the next few hours while it slowly sinks south. Most
of the strongest storms have been just north of this jet core this
evening. I would expect this to continue for several more hours.
The 1000/850 moisture transport from the RAP model shows the focus
of the moisture transport slowly sinking south along the lake
shore with a segement of it moving inland after midnight but the
core of it remains over Lake Michigan through 4 am, by then it is
focused on our the southwestern most sections of Lower Michigan. I
still believe the storms will continue through night as the line
of storms slowly sinks south. The effect bulk shear stays just
below 30 knots so severe storms will be limited but gusts to 30 to
50 mph are not out of the question near the lake shore.
&&
.SYNOPSIS...
Issued at 814 PM EDT Wed Aug 7 2019
- Thunderstorms will impact most of our western and central CWA
tonight with some stronger storms possible, area west of US-131
have the greatest risk of stronger storms. Most area north of
I-94 should see some rain overnight.
- Cooler and drier conditions return on Thursday and last into the
weekend
- Little to no chance of rain through the weekend after tonight
&&
.DISCUSSION...(This evening through next Wednesday)
Issued at 235 PM EDT Wed Aug 7 2019
Our main focus of the forecast is on convective trends through
tonight, and severe weather chances. The overall scenario has not
changed much over the last 24 hours, with convection likely for most
areas tonight, but only isolated severe weather possible for Lower
Michigan.
Convection has been a little ahead of schedule over Northern
Wisconsin this afternoon. It appears a 25+ knot low level jet is
helping to form a few storms up there. We believe that the forcing
with the low level jet will keep this convection north of our area
as it moves almost due east.
The convection we will be interested in is starting to form over NW
Wisconsin and NE Minnesota this afternoon. This convection is closer
to the cold front that will be moving over the area late this
evening and overnight tonight. The convection will be strongest over
Wisconsin where the front will move through during peak heating. The
Convective Allowing Models are in general agreement that the line
will approach the NW corner of the area toward Ludington after about
9 pm, and then move SE through the area through the overnight hours.
By the time the front arrives, diurnal instability will be on the
wane here. However, forecast soundings indicate that lingering
instability based at 1-2k ft above the night time surface inversion
will be sufficient to sustain at least scattered to broken
convection ahead of the incoming front, and mid level short wave
which will approach after midnight.
We are in good agreement with the SPC Day 1 outlook of a Marginal
chance of severe weather focused on our NW counties. The lingering
storms coming out of Wisconsin later this evening will slowly weaken
as they move SE later into the night with the loss of better low
level diurnal instability. As mentioned, there is a decent low level
inversion that develops toward dark and beyond, limiting the
potential of winds making it to the surface. It still will be
possible, with forecast soundings indicating over 1,000 J/kg of
downdraft CAPE. Can not rule out some marginally severe large hail,
but mid level lapse rates around 6.0 C/km and thinner CAPE profiles
in the -10 to -30C layer will limit hail size a bit.
Once the front clears the area Thu morning, we should gradually
clear out the clouds and somewhat humid conditions. Temperatures
will be a bit tempered with the NW flow ushering in cooler Canadian
air.
The remainder of the period through next Wednesday looks fairly
quiet and cooler, with little to no chances of rainfall. The
amplified upper air pattern by summer standards will hold much of
the period. Lower Michigan will be under the influence of NW flow
which will keep things from heating up too much. We will be just far
enough away from the jet axis much of the time to limit impactful
systems moving through. The threat of rain is not zero as a model or
two tries to break down the pattern, and brings systems through
Sunday and Tuesday. The more likely scenario is drier weather given
the pattern we are locked into with the amplified upper flow
pattern.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 652 PM EDT Wed Aug 7 2019
Based on the latest radar loops and knowing we have a decent upper
wave and surface cold front coming through tonight and there is an
organized low level jet, I believe all TAF sites will see rain
tonight. Even more than that the latest SPC SREF shows a very good
change thunderstorms will make it across all of Lower Michigan
between 03z and 09z. So I put that in all of the TAFs. The
greatest risk is for the I-96 TAF sites where I have lower
visibilities and ceilings in the TAF as the convective line moves
through the area. I did not play MVFR cigs behind the front since
I am on the fence with that but some the model guidance suggest
this is a good possibility. No matter what skies should clear by
midday Thursday. It will be breezy Thursday with winds of 15 to 25
knots as the cold air comes in.
&&
.MARINE...
Issued at 235 PM EDT Wed Aug 7 2019
We are not issuing any marine headlines with this forecast package,
however we are monitoring for a possible need for headlines tonight
and again on Thursday. Winds will come up a little tonight
immediately ahead of the incoming front. Indications are right now
that winds and waves will end up just short of criteria for an
advisory. If future trends indicate an upward trend, a headline
will be needed.
Same thing goes for Thursday in the wake of the front. High pressure
building in will push winds and wave close to criteria, but not
quite enough at this time to warrant an advisory. After Thursday,
conditions looks fairly benign then through the next few days with
quiet weather expected.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
MESOSCALE...WDM
SYNOPSIS...WDM
DISCUSSION...NJJ
AVIATION...WDM
MARINE...NJJ
Area Forecast Discussion
National Weather Service Wichita KS
629 PM CDT Wed Aug 7 2019
.SHORT TERM...(This evening through Friday night)
Issued at 330 PM CDT Wed Aug 7 2019
As of early this afternoon, the MCS that made its way southeast
across eastern Kansas this morning continues to push off into
southwest Missouri with a few lingering showers in far southeast
Kansas. Ahead of this feature, GOES-E visible satellite imagery
shows a well defined outflow boundary extending from roughly
Harper County, KS and southeast into Northern Oklahoma north of
the Tulsa metro area. Increasing cumulus development was noted
along and just to the south of this outflow boundary in northern
Oklahoma.
For the rest of the afternoon and evening, as the remainder of the
elevated convection in southeast Kansas exits the forecast area, the
more stable air should dampen any chances of convection across most
areas. As the previous mesoscale discussion mentioned, however, with
increased/significant heating in the vicinity of the outflow
boundary in northern Oklahoma, cannot completely rule out some
convective development along this boundary which has potential to
migrate back northward into the vicinity of southern Kansas. There
is plenty of available buoyancy with MLCAPE in the vicinity of
3500- 4500 J/kg and RAP forecast soundings suggest effective bulk
wind difference of 40-45kts along the southern tier of Kansas
counties over the next several hours. Convective inhibition has
been on a downward trend in the vicinity of the outflow over the
past few hours, and latest radar imagery shows a couple of storms
have already formed in the vicinity of Enid and Ponca City, OK.
Most short term and hi- res guidance favor a dry scenario for
southern Kansas, but think a few storms are certainly possible.
After 00z, convective inhibition significantly increases across
the entire forecast area once again, so although slight chance
pops were maintained in the forecast for the evening and tonight,
it is possible that these are still overdone for most areas within
the forecast area, particularly before 07z or so.
Temperatures have struggled today in the context of convective
activity for much of the morning and early afternoon in southeast
Kansas and portions of south central Kansas that were originally
included in a heat advisory today. As a result, many counties were
removed from the heat advisory early, and latest observations
suggest even those counties that remain (Kingman, Harper, Sumner)
will only reach advisory criteria for a brief time.
Overnight tonight and early tomorrow morning, a similar scenario as
last night/early this morning is expected with a complex of storms
forming in north central and northeast Kansas and then propagating
southeastward across the forecast area. The best chance for higher
precip amounts appears again to be along the Flint Hills corridor
and in southeast Kansas, where a Flash Flood Watch remains in tact
beginning at 01z this evening and lasting through the morning
tomorrow. Much higher rainfall amounts will be possible a little
further northeast of the area, but with precipitable water (PW)
values in excess of 2.0 inches in portions of central and southeast
Kansas, storms will be very efficient rain producers and present a
flood threat. In addition to flooding, with sufficient buoyancy,
moderate mid-level lapse rates, and roughly 40 kts or so of bulk
shear, some storms overnight/early tomorrow morning could be
strong to severe with hail and strong winds as the main threats.
By tomorrow, expect that most of the showers and storms will have
pushed into the southern portions of the area and down into
Oklahoma. However, have maintained POPs throughout the day, as
models hint at another subtle shortwave in the overall synoptic flow
could sustain shower/storm chances throughout the day and into the
evening.
Things should quiet down, at least temporarily, by around midday
on Friday before another shortwave brings more chances of showers
and thunderstorms overnight Friday night and again on Saturday
evening/night.
.LONG TERM...(Saturday through Wednesday)
Issued at 330 PM CDT Wed Aug 7 2019
In the long range, the mid/upper high over the southwest U.S. is
progged to slide slowly eastward across the southern CONUS from
Saturday-Tuesday of next week. A frontal passage looks to continue
the active pattern for the first half of next week, with fairly
decent chances of showers and storms again during the Monday-
Tuesday time frame. Temperatures will be more seasonable, with
afternoon highs averaging in the upper 80s and low 90s each
afternoon Saturday through the end of the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 625 PM CDT Wed Aug 7 2019
VFR conditions for all sites except for KCNU where their is a
possibility of a low CIG deck overnight and early tomorrow.
Anticipate VCSH and VCTS for KCNU and KSAL much of the overnight
and morning hours tommorow due to the NW flow aloft and
instability that is in place. Likely seeing another MCS type
system roll through. It is possible this could seep as far south
at KICT, however, I have kept mention out for now. Better TSRA
chances will creep in tomorrow but not confident with timing with
this fcst so I will keep out for now and add with later run.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 73 87 70 86 / 50 70 50 30
Hutchinson 72 86 69 85 / 40 60 30 20
Newton 71 84 70 84 / 60 70 50 30
ElDorado 71 84 70 85 / 60 70 60 30
Winfield-KWLD 73 87 71 87 / 40 50 50 30
Russell 70 85 67 87 / 50 40 20 30
Great Bend 71 86 68 85 / 40 40 30 20
Salina 71 83 69 86 / 60 70 30 20
McPherson 71 84 68 84 / 50 60 30 30
Coffeyville 73 85 72 87 / 50 60 60 40
Chanute 71 82 71 85 / 60 80 50 40
Iola 70 81 71 85 / 60 80 50 40
Parsons-KPPF 72 83 72 85 / 60 80 60 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Thursday morning for KSZ053-070>072-
095-096-099-100.
Heat Advisory until 8 PM CDT this evening for KSZ082-091-092.
&&
$$
SHORT TERM...TAV
LONG TERM...TAV
AVIATION...CWH
Area Forecast Discussion
National Weather Service North Platte NE
640 PM CDT Wed Aug 7 2019
.SHORT TERM...(This evening through Thursday night)
Issued at 318 PM CDT Wed Aug 7 2019
The rapid refresh models have analyzed a h700mb wave across the
Colorado front range this afternoon and a larger more formidable
disturbance near Salt Lake City. Thunderstorms are forming on the
Front Range in response to daytime heating and the h700mb wave.
Additional storm development is expected across ern Wyoming from
the Salt Lake disturbance. If these two areas of thunderstorms can
merge then very heavy rain will fall across swrn Nebraska
tonight, along and south of Interstate 80.
As it stands, the models are in good agreement developing a MCS
across the Plains tonight, but the track of the storm complex varies
from Interstate 70 in KS to near Interstate 80 in Nebraska.
The focus is an h850mb warm front poised along or south of the KS
border. Very high precipitable water between 1.5 and 2.0 inches will
be operating with 20kt winds at h500mb to produce heavy
thunderstorms. Winds at 300mb are stronger, near 40kts, suggests the
potential for brief severe storms. Given the fast and progressive
nature of the disturbance, it would seem wind damage will out-weigh
the threat of large hail.
POPs for this event have been raised to near the likely category and
the QPF forecast uses the wettest models such as the HRRR, RAP, HREF
and NAM. No flood watch will be issued with this forecast for a few
reasons. 1) the system appears to be fast moving. 2) the one hour
flood guidance is around 2 inches. 3) the predictability of the
track of MCS is low. 4) some models like the HRRR develop very
little storm activity across Wyoming and favor KS over Nebraska for
heavy rainfall.
Moisture availability suggests an inch of rainfall could fall in 20
minutes as the storms roll through swrn Nebraska tonight and this
will likely produce localized flooding. Storm activity should be in
or approaching the eastern Panhandle around 23z this afternoon.
The models are mostly quiet, rain-wise, Thursday and Thursday night.
The SREF and NAMnest suggest storm activity developing on the
Cheyenne divide Thursday afternoon. This could affect the Panhandle
and swrn Nebraska Thursday night. Otherwise rain chances are mostly
isolated.
.LONG TERM...(Friday through Wednesday)
Issued at 318 PM CDT Wed Aug 7 2019
The GFS and GFS ensemble are circulating another subtropical
disturbance, currently over Baja Mexico, north through the Rockies
and into Nebraska Saturday night. The ECM and GEM models are a
bit south of the GFS. The SREF, GFS and NAM models show a surge of
moisture ahead of the disturbance with precipitable water
increasing to over 1.5 inches. Considering the dynamics and
moisture available, the POP forecast is on the low side with just
40 percent in place. Later forecasts will likely raise this rain
chance if the model forecast continuity is good.
The subtropical moisture aloft and Gulf moisture in the lower levels
is expected to decrease early next week. This is in the wake of a
fairly strong cold front forecast to move through Sunday. High
temperatures fall off into the upper 70s to lower 80s Sunday and
beyond and rain chances become mostly isolated after Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 640 PM CDT Wed Aug 7 2019
Thunderstorm impacts continue to remain the greatest aviation
concern in the current TAF cycle. A secondary concern will be low
ceilings overnight and into Thursday morning. So far the storm
coverage has been isolated and mainly confined to the west and
north central Nebraska. In time we expect a greater coverage of
storms, but not enough to warrant a prevailing group for either
LBF or VTN. Initial storms may be severe with large hail,
significant reductions in visibility and erratic gusty wind.
Behind the storms, showers will give way to stratus overnight with
MVFR or locally IFR possible.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Jacobs
Area Forecast Discussion
National Weather Service Spokane WA
509 PM PDT Wed Aug 7 2019
.SYNOPSIS...
The heatwave continues into Thursday with temperatures reaching
well into the 90s with many places while central Washington sees
triple digits. Wildfire smoke will plague parts of the Inland
Northwest contributing to areas of poor air quality. Much cooler
weather will arrive this weekend with showers likely, breezy winds
and chance of thunderstorms. Drier weather arrives early next
week with seasonal temperatures.
&&
.DISCUSSION...
Tonight through Wednesday night: The weather pattern across the West
is defined by a weak, closed upper low off the Pacific Northwest and
high pressure over the Four-Corners region. The Inland Northwest
resides under southwesterly flow aloft between the two systems. A
few convective showers are starting to pop across the central WA
Cascades, and convection is also noteworthy across northeastern
Oregon this afternoon.
Heat...
Hot temperatures are manifesting across the region this afternoon,
and on track to peak in the upper 90s up to about 105 degrees
across much of the lowlands. A couple of degrees of cooling is
expected for Thursday, but moderate to high heat risk is still
projected across much of the region. As such, we will extend the
Heat Advisory through Thursday evening.
Smoke...
Thick smoke continues to come off the actively burning Williams
Flats and Eagle Bluff wildfires. The latest satellite imagery
shows wildfire activity carrying smoke from the Williams Flats
eastward, with ground reports of smoke in Spokane and portions of
northern Idaho. The HRRR Smoke model confirms this. Expect smoke
to continue to be problematic in some areas through Thursday.
Thunderstorms...
Isolated thunderstorms will be possible this afternoon and
evening along the central WA Cascades. Additionally, thunderstorms
will be possible this evening along the Washington Blue
Mountains, tracking northeast to the Camas Prairie.
More widespread activity will start to be possible later Thursday
as a shortwave tracks northward. Convection will again be
possible along the Cascades, but activity in eastern WA and
northern ID may be more noteworthy. Look for convection to
initiate in eastern Oregon in the afternoon, lifting northward in
the evening and overnight. A fair amount of elevated instability
will accompany this shortwave, with NAM projections of 200-500
J/kg MUCAPE and elevated modified Total Totals. As such, it looks
like there is a fair potential of nocturnal thunderstorms Thursday
night, with eastern Washington and northern Idaho having the
highest chances.
Dang
Friday through Saturday night: Disturbances running up south to
north through the ridge negatively tilted ridge in place over
Eastern Washington and North Idaho provide the trigger for
convection Friday. The storm motion would be very slow to the
north at less than 5 mph thus any slow moving wet thunderstorm
will have the potential to produce flash flooding. The storm
motion remains rather slow continuing on into sometime Saturday as
the closed low off the coast ejects and starts moving through
Eastern Washington and North Idaho. As such pops and QPF are
increased substantially coupled with significant cooling. /Pelatti
&&
.AVIATION...
00Z TAFS: VFR conditions across the region at this hour. Wildfire
smoke from the Williams Flats Fire will continue to be a problem,
and may bring MVFR visibility to KGEG & KSFF starting around 03z
Thursday. Confidence is low though.
Isolated thunderstorms will be possible along the Cascades this
evening, and along the Blue Mountains and Camas Prairie. While
these thunderstorms aren`t expected to directly impact the TAF
sites, they may be in the vicinity of KLWS and KEAT. The main
threat with these storms is gusty winds and lightning.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 62 96 64 85 59 80 / 0 0 10 30 20 60
Coeur d`Alene 61 95 63 83 58 80 / 0 0 10 30 20 60
Pullman 58 91 58 83 54 76 / 0 10 40 30 20 70
Lewiston 69 98 68 90 64 83 / 20 20 40 30 30 70
Colville 52 102 55 90 52 86 / 0 0 10 30 30 70
Sandpoint 57 93 60 82 57 79 / 0 0 10 30 40 70
Kellogg 66 92 65 79 61 78 / 0 0 30 30 40 70
Moses Lake 64 98 62 90 60 81 / 0 0 10 10 20 40
Wenatchee 70 95 68 88 67 79 / 10 10 20 20 30 60
Omak 66 100 68 90 65 83 / 10 10 10 20 40 70
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Fire Weather Watch from late Thursday night through Saturday
evening for Northern and Central Idaho Panhandle (Zone
101).
Heat Advisory until 8 PM PDT Thursday for Coeur d`Alene Area-
Idaho Palouse-Lewis and Southern Nez Perce Counties-
Lewiston Area.
WA...Fire Weather Watch from late Thursday night through Saturday
evening for East Washington Central Cascade Mountains (Zone
682)-East Washington Central Cascade Valleys (Zone 677)-
East Washington North Cascades (Zone 685)-East Washington
Northeast (Zone 686)-East Washington Northern Columbia
Basin (Zone 673)-East Washington Okanogan Highlands (Zone
687)-East Washington Okanogan/Methow Valleys (Zone 684)-
East Washington Palouse and Spokane Area (Zone 674)-East
Washington South Central Cascade Mountains (Zone 680)-East
Washington South Central Cascade Valleys (Zone 676).
Heat Advisory until 8 PM PDT Thursday for Lower Garfield and
Asotin Counties-Moses Lake Area-Northeast Blue Mountains-
Northeast Mountains-Okanogan Highlands-Okanogan Valley-
Spokane Area-Upper Columbia Basin-Washington Palouse-
Waterville Plateau-Wenatchee Area.
Heat Advisory until 8 PM PDT Thursday for East Slopes Northern
Cascades.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
306 PM MDT Wed Aug 7 2019
.SHORT TERM...(This evening through Thursday)
Issued at 245 PM MDT Wed Aug 7 2019
...Heavy Rain and Flash Flooding Possible Tomorrow...
Current water vapor imagery and upper air analysis is indicating
generally weak to moderate west to southwest flow aloft across the
region, with the center of a large upper level high across south
central New Mexico and a broad upper trough translating across the
Northern Tier at this time. Water vapor imagery is also indicating
the monsoonal moisture plume across the Desert SW continuing to move
into the Rockies, with PWATS of 0.8 to 1.2 inches (100-130 percent
of normal) across the area this afternoon. Regional radars are
indicating scattered to numerous showers and storms over the higher
terrain, with a few storms spreading east across the adjacent
valleys and plains at this time. SPC meso analysis is indicating mu
capes ranging from 500 to 1000 j/kg over and near the higher
terrain, and up to around 2000 j/kg and effective shear 20-40kts
(strongest northeastern Colorado) across the eastern Plains.
Tonight and Tomorrow...Followed HRRR trends for pops tonight, which
spreads scattered storms across the I-25 Corridor through the early
evening and out across the far southeast Plains and into western
Kansas through the late evening and into the overnight hours. A
few strong storms will be possible across the far southeast
Plains, with the better shear and instability in place. Also kept
isolated pops across the higher terrain through the early morning
hours, as monsoonal moisture continues to advect to the region.
Passing Northern Tier system sends a backdoor front across the
eastern Plains late tonight, with moist easterly upslope flow
deepening across eastern Colorado through the day tomorrow. This
combined with increasing monsoonal moisture (PWATS progged between 1-
1.5 inches (125-175 percent of normal)) and another weak disturbance
moving through the flow, will again see scattered to numerous
showers and storms developing across the higher terrain through the
late morning and afternoon, with storms spreading east through the
afternoon and evening. Weak westerly steering flow and the abundant
available moisture will bring heavy rain across the area tomorrow,
along with the potential for flash flooding. With that said, have
issued a flash flood watch for the newer burn areas of the Spring,
Junkins and Hayden Pass scars. Later shifts may need to include
areas along the Palmer Dvd and I-25 Corridor, if models continuing
to indicate storms slowly moving across these areas through the
later afternoon and evening. Should see warmer overnight lows
tonight, with more cloud cover and increasing low level moisture,
with highs tomorrow slightly cooler than today.
.LONG TERM...(Thursday night through Wednesday)
Issued at 245 PM MDT Wed Aug 7 2019
The weather pattern will remain active over the next several days
with the monsoon fetch and embedded disturbances moving across
southern Colorado. Models keep widespread convection going through
the night across the southeast mountains and plains with NAM the
most heavy handed with QPF behind the front Thursday night. With
high precipitable waters and upslope flow, flash flooding will be
the main concern, especially for burn scars, though there will be
sufficient CAPE and shear for a few marginally severe storms
across the plains. Flash flood watch will continue until 06z for
now with the possibility that later shifts may need to expand the
area eastward or extend the timing depending on latest high res
model data.
Friday looks similarly active with surface dew points staying up in
the mid 50s to mid 60s across the plains. Good monsoon fetch will
keep precipitable waters high across the mountains as well. Low
level flow becomes more southerly and with the amplifying ridge
over head, this should limit deep layer shears. But there will
still be plenty of CAPE for a pulse type severe thunderstorms.
Main concern will be potential for flash flooding though, and
Friday may be round 2 for that as GFS continues to show a
favorable track for impulses embedded within the monsoon plume to
ride northeastward across southern CO. May have another round of
flash flood watches this day which may need to be expanded farther
east across the plains depending on how rainfall stacks up the
day before.
Saturday and Sunday look similarly wet. There may be some subtle
drying out west on Saturday but monsoon plume quickly recharges for
Sunday with precipitable waters back up to .75 in the west to 1.5 in
the east. Will likely have consecutive days of flash flood
concerns, especially on burn scars.
Passing upper trough to the north will bring some drying to southern
CO early-middle of next week. There will still be sufficient
moisture for afternoon thunderstorms, but they should become less
widespread which should limit the threat for burn scar flash
flooding. Temperatures should also heat up again. -KT
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 245 PM MDT Wed Aug 7 2019
More available moisture working into the region within weak west to
southwest flow aloft will allow for better coverage of afternoon
showers and storms to develop across the higher terrain today.
Storms will slowly push east off of the higher terrain and across
the adjacent valleys and plains through the late afternoon and
evening hours, with all three taf sites having the potential to see
storms move across the terminals. Storms will be capable of
producing brief periods of MVFR conditions in heavy rain, with gusty
outflow winds up 50 mph and small hail possible with the stronger
storms. Storms to diminish and end by midnight, with VFR conditions
expected through 18Z. A better coverage of storms is expected across
the area tomorrow afternoon, with brief MVFR and local IFR
conditions possible with afternoon storms.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from Thursday afternoon through Thursday
evening for COZ072>075-079-080-087.
&&
$$
SHORT TERM...MW
LONG TERM...KT
AVIATION...MW