Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/14/19

Area Forecast Discussion

National Weather Service La Crosse WI

 1100 PM CDT Tue Aug 13 2019

.SHORT TERM...(Tonight Through Wednesday Night)
Issued at 144 PM CDT Tue Aug 13 2019

Current water vapor imagery this afternoon showing a fairly vigorous
mid-level circulation rotating southeast through MN. Ongoing very
scattered convection already but forcing from wave is expected to
fire more scattered thunderstorms through this evening. RAP has
surface-based cape in the 2000-2500J/kg range with 0-3km bulk shear
around 25kt. Could see a few stronger storms early on in this
scenario with stronger/possibly damaging winds and some larger hail.
CAPE trails off with loss of surface heating later in the evening,
so expecting storm intensity to diminish rapidly by mid/late
evening. However, looks like scattered showers will continue into
the overnight hours with cyclonic flow aloft and weak mid-level
frontogenesis lingering.

Shower/isolated thunder chances continue Wednesday as models show a
lingering surface trough extending across areas mainly south of I-
90. In addition, looks like another weak mid-level impulse ripples
southeast across this area. NAM only showing 1000-1500J/kg of MUCAPE
with 10-15kt of shear...so just pulse type/garden-variety storms
expected. Otherwise, a cooler day on tap with highs generally in the
70-75 degree range.

High pressure builds in Wednesday night for partly cloudy and quiet
conditions. Will have to watch for areas of fog with recent
rainfall/clearing skies/light winds.

.LONG TERM...(Thursday through Tuesday)
Issued at 144 PM CDT Tue Aug 13 2019

Thursday is looking like a pleasant day as high pressure remains in
control. Under mostly sunny skies, plan on temperatures topping off
in the 70s. For Thursday night into Friday, will be watching another
mid-level trough dropping out of the Dakotas into the Upper
Mississippi River Valley. This will bring another chance of showers
and storms into the area.

Parade of embedded mid-level troughs rotate across the area in broad
long wave trough aloft through the weekend for off and on
shower/storm chances. Look for highs Sat/Sun in the mid 70s to the
lower 80s.

Decreasing shower/thunder chances look on tap for Monday and Tuesday
as mi-level/surface ridging takes place across the central
CONUS/Upper Mississippi River Valley region.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1058 PM CDT Tue Aug 13 2019

Low pressure over the TAF sites will focus moisture and allow for
ceilings to drop to IFR or very low MVFR /KLSE/ overnight. With
little change in the pattern through the day and no fronts moving
through, the clouds will be slow to dissipate. Scattered light
rain showers will likely be around the KLSE field.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&

$$

SHORT TERM...DAS
LONG TERM...DAS
AVIATION...Baumgardt



Area Forecast Discussion

National Weather Service Denver/Boulder CO

 715 PM MDT Tue Aug 13 2019

.UPDATE...
Issued at 715 PM MDT Tue Aug 13 2019

A strong outflow boundary is pushing west across the Front Range
at this time. Dew points behind the boundary are in the upper 50s
to lower 60s. Many of the Convective Allowing Models (CAMs) show a
few strong to severe storms forming 9pm to 11pm along the Front
Range, including several past hours of the HRRR model. Going
forecast and messaging that strong to severe storms will remain
possible for the Front Range Urban Corridor through the evening
appears on track.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 316 PM MDT Tue Aug 13 2019

Severe thunderstorms with multiple tornadoes, large hail and
damaging wind gusts are ongoing across far eastern Colorado
mainly in Goodland`s CWA. An outflow boundary from these storms
will push westward this evening pushing up against the foothills
around 02Z. High resolution models are starting to come into
better agreement that storms will develop mainly over Boulder and
Larimer Counties so I increased QPF and POPs over these counties.
These storms may be able to tap into most unstable CAPE of 2000 to
3000 j/kg and produce large hail. The unusual timing of this
potential for hail may throw people off so we have been trying to
emphasize this threat a bit.

The aforementioned outflow boundary will bring in moist air with
dew points in the low to mid 60s to the plains and urban corridor
tonight. Patchy fog and low stratus will likely develop mainly on
the north side of the Denver metro to the eastern plains.

The low clouds will keep the moisture in place across the plains
during the day tomorrow. Moderate to strong instability will be in
place tomorrow with mixed layer CAPE between 2500 to 3000 j/kg
along with deep layer shear around 35-45 knots. Considering these
parameters, strong to severe storms will be possible across lower
elevations with large hail and damaging wind gusts the primary
threats. The limiting factor will again be the forcing. Models
don`t show a shortwave and may even indicate some weak NVA. This
may be why models seem a bit bearish on the coverage of storms
tomorrow. Therefore, there is low confidence in the thunderstorm
threat tomorrow. Otherwise, I lowered highs tomorrow a few degrees due
to the morning clouds and better moisture in place.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 316 PM MDT Tue Aug 13 2019

Thunderstorms will diminish late Wednesday night from northwest
to southeast. Storms could stick around past midnight over the far
eastern plains. Forecast soundings indicate instability and
moisture will remain sufficient with only a slight low level
inversion remaining in place. Outflow interactions would be enough
to lift parcels into regions of roughly 2,500 J/kg of CAPE.

Thursday isolated afternoon storms over the plains will develop
along the Wyoming border and the Palmer Divide. Late in the
afternoon showers and storms will spread across the plains. With
less low level moisture near the mountains, any convection there
will likely be high based with gusty winds, while there may still
be some stronger convection near the eastern border. Early Friday
morning patchy fog could develop east of Denver with low level
moisture, but surface winds up to 20 knots may lead to more low
cloudiness instead of fog. There are mixed signals about the
amount of moisture left in the east on Friday, with some runs
showing outflow keeping the convective potential similar to
Thursday. Other runs are drier.

Zonal upper level flow will be in place Friday, with an upper
level ridge building northward through the Rockies over the
weekend. This will lead to warmer temperatures and allow much
drier air aloft to move over Colorado. This should lead to a
minimum of convection. Model blend is giving highs in the mid 90s,
though it`s possible one or two of these days could be even
warmer. By Tuesday some of the model runs have a little moisture
creeping north far enough to give us a bit more cloud cover,
convection, and maybe a little cooling, while others have no
change yet.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 715 PM MDT Tue Aug 13 2019

Outflow from thunderstorms over northeast Colorado has raced
through the Denver area and will continue to bring gusty east
winds through the evening. This will increase moisture and bring
isolated to scattered thunderstorms after 02Z. Best chance for
storms at this time appears to be near the foothills. Went with a
tempo for BJC. Chances for storms are lower at DEN and APA, but
not zero. With the increase in moisture, low clouds are expected
to form over eastern Colorado. Some uncertainty as to how far
southwest they make it into the Denver area. Ceilings are expected
to fall to 500-1000 feet over eastern Colorado. Dry air quickly
moves in Wednesday morning and will erode the low clouds by 14Z,
if not sooner.

There will be a threat for storms to develop Wednesday afternoon
but it will be a very low chance. Gusty winds and lower ceilings
would be the main threats were storms to move over the terminals.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Meier
SHORT TERM...Danielson
LONG TERM...Sullivan/Gimmestad
AVIATION...Meier




Area Forecast Discussion

National Weather Service Columbia SC

 1024 PM EDT Tue Aug 13 2019

.SYNOPSIS...
Scattered thunderstorms expected into tonight ahead of an
approaching cold front. The front will slip into the forecast
area Wednesday and provide greater chances for showers and
thunderstorms. This front will slowly slip toward the southern
forecast area and Coastal Plain Thursday and hang up near the
coast Friday keeping a chance of showers and thunderstorms
through the long term.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
There will be a continued chance of thunderstorms overnight
because of some convergence ahead of the approaching cold front
plus slightly lowering mid-level temperatures ahead of weak
shortwave troughing. There were upstream thunderstorms in north
Georgia and the North Carolina mountains at 1000 pm. Weakening
may occur because of relatively warm mid-level temperatures with
h7 values near 10 C combined with nocturnal cooling. The high-
resolution models previously indicated little coverage in the
forecast area overnight but the HRRR has trended with greater
coverage. We have increased pops, but still kept in the chance
category for now. There may be enough lingering instability
combined with some dry air in the mid levels in the northwest
flow to help produce strong wind with the thunderstorms. Mixing
and cloudiness should hold up temperatures. Expect lows in the
middle and upper 70s.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
A cold front will push across the Southeast Wednesday bringing
numerous showers and thunderstorms. Warm, moist advection ahead
of the front will allow temperatures to rise into the mid 90s,
possibly upper 90s in some spots, with dewpoints in the low to
mid 70s. This combination of heat and moisture will allow Heat
Index (HI) values to range between 105 and 110 during the
afternoon. However, HI values near Heat Advisory criteria may be
brief. There is potential for morning cloud cover from stratus
and convective debris clouds as well as rain cooled air
disrupting heating in the afternoon. A Heat Advisory may be
needed but confidence will increase by Wednesday morning as
satellite trends give us a better idea of morning cloud
coverage.

Thunderstorms will develop during the afternoon. The two most
notable boundaries will be the front near or over the western
FA and sea breeze/cold pool boundaries that form in the coastal
plain. Convection allowing models suggest that initially the
greatest coverage will be along the coastal plain but as these
two boundaries interact the forcing for convection will shift
farther inland over the Midlands and CSRA during the late
afternoon/evening.

Severe Weather Potential: Instability will be moderate to high
during the day with SPC HREF mean sbCAPE values between 2000 and
3000 J/kg. Mid-level lapse rates are also expected to be steep, for
the time of year. Damaging downburst winds from pulse-type
storms will be the main threat given the weak shear/helicity
values. In addition PWAT values exceeding 2 inches support
locally heavy rainfall and isolated flash flooding. One factor
that limits confidence will be how far the convection that
occurs Tuesday advances into the Midlands and CSRA. Widespread
thunderstorms Tuesday evening/overnight may limit potential
instability Wednesday afternoon.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
The frontal boundary will slide toward the southern FA and
Coastal Plain Thursday, where a locally heavy rain threat will
remain. A broad, upper-level trough will move over the eastern
US Friday into the weekend as the stalled front and greatest
moisture remain near the coast. This will keep at least a chance
of rain in the forecast each day. The models have come into
better agreement for the end of the long term. Upper-level
energy digs into the Deep South early next week with models
developing a surface low near the Gulf of Mexico and lifting it
northward across the Southeast. This will keep the chance of
rain going through the end of the long term. Warm advection
associated with the low will offset some of the insolation from
cloud cover. Model guidance suggest daytime temperatures will be
warmer than previously forecasted, with values near or slightly
above normal.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
There may be restrictions at times in thunderstorms.

There will be a continued chance of thunderstorms overnight
because of some convergence ahead of the approaching cold front
plus slightly lowering mid-level temperatures ahead of weak
shortwave troughing. There were upstream thunderstorms in north
Georgia and the North Carolina mountains at 1000 pm. Weakening
may occur because of relatively warm mid-level temperatures with
h7 values near 10 C combined with nocturnal cooling. The high-
resolution models previously indicated little coverage in the
forecast area overnight but the HRRR has trended with greater
coverage. We have increased pops, but still kept in the chance
category for now with uncertainty too high to include in the
terminal forecasts for now. There may be enough lingering
instability combined with some dry air in the mid levels in the
northwest flow to help produce strong wind with any thunderstorms.

The cold front will be close to the area Wednesday. There
will be scattered to numerous thunderstorms. Moderate
instability supports a possibility of strong wind with any
thunderstorms. We did not include thunderstorms in the terminal
forecasts at this time because of timing uncertainty but the
greatest chance may be late Wednesday afternoon as indicated by
some of the high-resolution models.

Outside of thunderstorms expect mainly VFR conditions with
instability and mixing diminishing the risk of fog and low
cloudiness. Most of the NAM and GFS MOS, HRRR, plus most SREF
members maintain VFR conditions. The NAM and GFS MOS support
mainly southwest to west wind 5 to 10 knots.

EXTENDED AVIATION OUTLOOK...A moist southerly flow may help support
fog and stratus during the early morning hours. Scattered showers
and thunderstorms are expected mainly during the afternoons and
evenings.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.

&&

$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99




Area Forecast Discussion

National Weather Service Hastings NE

 641 PM CDT Tue Aug 13 2019

.SHORT TERM...(This evening through Wednesday)
Issued at 334 PM CDT Tue Aug 13 2019

Aloft: RAP tropopause analyses and aircraft wind data show low-
amplitude zonal flow over the CONUS with a flat/suppressed
subtropical high along the LA/TX coast. A wk shrtwv trof was
making its way thru the Nrn Rckys. This trof will cont E tonight
passing just N of the CWA. In its wake...the flow will veer to the
WNW tomorrow.

Surface: Very wk high pres was over NEB. 1011 mb low pres was
over MN with a cool front extending W along the SD-NEB border into
MT. This high will disappear while the cool front slips S thru
the CWA tonight. Nrn Plns high pres behind the front will quickly
drop S into NEB tomorrow.

700 mb WAA/FGEN in the RRQ of a 60 kt upr-lvl jet streak resulted
in a persistent area of shwrs and a cpl tstms this morning over
the Sandhills. Some of the light shwrs moved acrs S-cntrl NEB this
morning...along and N of Hwy 6. They have long since dissipated
leaving sunny skies.

Rest of this afternoon: Sunny but incrsg thick cirrus blow-off
from svr tstms in SW NEB.

Tonight: Mostly cldy as significant anvil blow-off from tstms to
the W streams over the CWA. A slight chance of a shwr/tstms...
primarily W and S of the Tri-Cities. Lows a little below
normal...in the 60s except upr 50s Valley/Greeley counties.

Upslope flow and convergence in the lee trof was resulting in svr
tstms firing over SE NEB. CAMs are indicating these storms will
congeal and grow upscale into an MCS that propagates SSE into Wrn
KS. There is a chance the Ern fringe of these tstms could clip the
SW part of the CWA...from Cambridge-Phillipsburg-Plainville.
Can`t completely rule out a svr tstm...but odds favor them
remaining just W-SW of the CWA.

There are a cpl mdls that suggest a few tstms could dvlp along
the NEB-KS border or down in N-cntrl KS toward dawn. Kept a 20 POP
in the fcst to cover this. It`s far from certain.

Wed: Some uncertainty but believe it will probably play out as
dcrsg clds during the morning...espcly over S-cntrl NEB. Overall
should average mostly sunny and dry. Did keep a 20 POP just in
case something rogue pops up as suggested by a cpl mdls.

Wed will be the coolest day of the wk with temps svrl degs below
normal (78-84F over S-cntrl NEB/80-87F over N-cntrl KS).

.LONG TERM...(Wednesday night through Tuesday)
Issued at 334 PM CDT Tue Aug 13 2019

Aloft: The last 2 runs of the global mdls GFS-FV3/EC/CMC/UKMET
have come into much better agreement vs 24-36 hrs ago yielding
greater fcst confidence. Low-amplitude WNW flow will remain over
NEB/KS thru Sun. From Thu night thru Sat...svrl shrtwv trofs are
fcst to cross the rgn which will turn the WNW flow cyclonic. The
strongest of these trofs is slated to move thru Sat. As that trof
departs to the E...heights will rise Sun-Tue as the subtropical
high over NM expands.

Surface: These days will alternate with very weak cool frontal
passages followed by high pres the next day. Wk cool fronts are
fcst to cross the CWA Thu night...Sat and Tue.

Temps: Averaging slightly cooler than normal.

Rain/Tstms: Lots of uncertainty due to typical weak summer
forcing. Isold or sct tstms will be possible thru Sat night. Some
storms could be svr at times.

&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 640 PM CDT Tue Aug 13 2019

Overall a fairly quiet forecast is expected with some caveats. 1.
There is a small chance for thunderstorms during the
overnight/early morning hours. Otherwise the best chance for
storms is during the afternoon/evening Wednesday. Due to the small
chance for storms, have left the mention out of the TAFs at this
time. Winds are light and generally northerly, that being said
brings caveat 2. A wake low has formed in the trailing stratus of
the MCS in northern Kansas and a 60 mph wind was reported at KLXN
about 6pm Tuesday night. KEAR has some gusts to 15 mph and winds
are out of the south. Winds will be light and northerly for much
of the forecast.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&

$$

SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Billings Wright



Area Forecast Discussion

National Weather Service Newport/Morehead City NC

 1009 PM EDT Tue Aug 13 2019

.SYNOPSIS...
A cold front will slowly approach the area Wednesday and
Thursday then dissipate over the region this weekend. High
pressure offshore will dominate early next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/..
As of 10 PM Tuesday...Active convection from earlier in the
evening has dissipated with only light showers continuing across
the northern quarter of the CWA at late evening. This activity
should end shortly with a lull of a few hours overnight. Latest
HRRR and 3KM NAM show developing of scattered showers/storms
near the coast toward morning and will have 30-40 pct PoPs for
these areas with lower PoPs inland. Lowered overnight lows given
some rain cooled air in spots, but should generally be low/mid
70s inland and 75 to 80 degrees closer to the coast.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
As of 245 PM Tue...Similar pattern persists Wed, with cold
front approaching the area and shortwave energy moving through
the flow aloft. SPC continues to outlook the area in a Marginal
Risk for severe weather, while WPC has the area outlooked in a
Slight Risk for excessive rainfall. Isolated to widely scattered
showers/tstms possible early, becoming scattered to numerous
during the afternoon and evening. Will continue high chance to
likely pops. MU CAPE values expected around 3000 J/kg, bulk
shear 20-30 kt, and PWATS climbing well over 2 inches. The main
threats still looks like damaging wind gusts and locally heavy
rainfall.

Heat and humidity will continue as well. High temps likely in
the upper 80s to low 90s, combined with dewpoints in the 70s,
many areas will likely see heat index values around 105 deg.
Will be very close to Heat Advisory criteria, but will hold off
now given some uncertainty with early cloud cover and afternoon
convection.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
As of 230 PM Tue...A cold front will approach the area mid to
late week leading to unsettled weather. The front will gradually
dissipate over the region this weekend.

Wednesday night through Thu... The broad ridge starts to break
down as a trough develops over the eastern US. A cold front will
slowly approach from the NW through Thu. The numerous shra/tsra
will grad push to cst Wed night with cont likely pops and
locally heavy rain.

The front conts to slowly approach Thu and expect good cvrg of
shra/tsra with short wave passing thru broad ern US trof. Mdls
show better moisture closer to cst so have chc pops well inland
to likely cst. Temps will cool a bit Thu with highs mainly in
the 80s.

Fri through Monday...Better moisture begins to shift to cst late
in week into the weekend as the front sags into the area and
gradually dissipates. Will keep chc pops for the cst with mainly
slight chc inland thru Sunday. As offshore high pres becomes
dominant early next week expect just isold sea brz activity.
With hgts building a bit over the weekend into early next week
and mdls now not showing much E to NE wind raised temps a bit
with highs around 90 or low 90s inland with mid/upr 80s beaches
most of the period.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term /through Wednesday/...
As of 745 PM Tuesday...MVFR conditions at PGV/ISO due to
convection currently but will improve to VFR by 03Z, with
EWN/OAJ persisting at VFR through most of the TAF period. Showers
and storms will continue to wane this evening with loss of
daytime heating. Expect winds to stay up enough tonight combined
with increasing clouds to limit fog threat. Scattered to
numerous showers and storms expected to develop Wednesday
afternoon and evening.

Long Term /Wednesday night through Sunday/...
As of 230 AM Tue...Bouts of shra/tsra expected through Thu as a
cold front approaches from the NW. Some brief sub VFR with
gusty winds poss with convection but shld be mainly VFR outside
of the shra/tsra. Deeper moisture begins to shift mainly E of
taf sites Fri into the weekend with less shra/tsra coverage and
mainly VFR. As usual some patchy fog/st poss early morn espcly
late in week after most areas see decent rainfall.

&&

.MARINE...
Short Term /through Wednesday/...
As of 1010 PM Tuesday...SW winds becoming a bit more gusty at
15-20 knots at late evening with seas 2-3 feet. These winds
should continue overnight. Moderate SW winds 10-20 kt will
continue Wed. A few gusts to 25 kt possible late Wed afternoon
and evening as well as thermal gradient strengthens. Seas of 2-3
ft will build to 3-5 ft toward morning and continue into Wed.

Long Term /Wednesday night through Sunday/...
As of 230 AM Tue...The pres gradient is expected to relax a bit
Thursday as winds become SW 10-15 knots. The weakening front
tries to push into the area Fri and Sat but looks like will
dissipate with any post frontal winds very light with dir grad
becoming S/SE again later Sat. 3 to 5 ft seas expected Wed and
Wed night and could come close to 6 ft at times outer central
wtrs. Seas grad subside to 2 to 4 ft Thu and Fri and mainly 2 to
3 ft Sat.

&&

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.

&&

$$

SYNOPSIS...MHX
NEAR TERM...CTC
SHORT TERM...CQD
LONG TERM...RF
AVIATION...DAG/RF
MARINE...DAG/CTC/CQD




Area Forecast Discussion

National Weather Service Marquette MI

 748 PM EDT Tue Aug 13 2019

.SHORT TERM...(This evening through Wednesday)
Issued at 409 PM EDT TUE AUG 13 2019

WV imagery and RAP analysis indicated mainly zonal pattern through
the northern CONUS with troughing over eastern Canada. At the
surface, a ridge extended from southern Saskatchewan through
northern Ontario while a weak trough stretched from southern WI to
eastern North Dakota. Weak radar returns persisted through central
Upper Michigan near lake breeze boundaries and in an area of weak
900-700 mb fgen. Otherwise, vis loop showed clouds lingering over
most of Upper Michigan.

Tonight, any remaining sprinkles or light showers should diminish
during the afternoon. Northwest mid level flow from northern into the
northern Great Lakes will keep the MN shrtwv south of Upper
Michigan. Expect slightly drier to push into Upper Michigan with
anticyclonic northerly low level flow. However, enough clouds may
linger to limit radiational cooling and amount of temp dropoff
overnight. So, temps maintained toward the middle of guidance with
inland readings into the upper 40s and readings in the mid to
upper 50s closer to the Great Lakes.

Wednesday, high pressure building into the area will bring enough
sunshine with inland cu to boost temps into the lower 70s south.
Onshore flow should keep readings in the upper 60s near Lake
Superior. Mixing to 5k ft inland will also drop dewpoints into the
upper 40s.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 403 PM EDT TUE AUG 13 2019

As an upper trough axis swings through tomorrow night, look for just
the slightest of chances for some light showers to pop-up, currently
looking to primarily stick to the Lake Superior shoreline, with
perhaps some orographic assistance in the western U.P. Other than
perhaps some sprinkles on Thursday, it should remain largely dry
through the forecast area, with low-end PoP chances starting to creep
back in from the west late tomorrow night into early Friday. By
later in the day, those chances rise as yet again as another weak wave
rotates across the Upper Great Lakes. Saturday is trending toward
being a bit more active as compared to Friday with more widespread
convection possible. The responsible feature is a shortwave riding
out ahead of its main trough, with the parent trough approaching the
region from out of the Dakotas. As it swings through, models are in
decent agreement of it becoming negatively-tilted. This may be the
system to watch a bit more closely as this time frame approaches.

Once the trough swings through over the weekend, stout high pressure
is depicted to build in, leaving the area dry into early next week.
Could see yet another blocking pattern emerge as a ridge over the SW
U.S./Southern Plains builds back in. Temperatures this week largely
remain seasonable, with rising temps by the weekend, with widespread
80s for highs likely returning.
&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 748 PM EDT TUE AUG 13 2019

VFR conditions are likely to prevail thru the fcst period at
KIWD/KCMX/KSAW. However, MVFR cigs will occur at KIWD for the next
hr. In addition, some patchy ground fog may develop at KSAW and
especially at KIWD during the night.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 409 PM EDT TUE AUG 13 2019

Winds over the lake are expected to stay at or below 20 knots
through the week. Models are indicating the chance for an active
period of weather this upcoming weekend. Expect chances of showers
and thunderstorms as well as the chance at gusty conditions one of
the days. Confidence in timing is too low for specifics at this
time.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...JLB
LONG TERM...lg
AVIATION...Rolfson
MARINE...JLB




Area Forecast Discussion

National Weather Service Topeka KS

 912 PM CDT Tue Aug 13 2019

.UPDATE...
Issued at 912 PM CDT Tue Aug 13 2019

Looks like the MCS across western KS will remain west of the
forecast area this evening. Latest IR imagery shows the strongest
updrafts propagating south southeast as tops warm. Additionally
models prog the instability axis over the next few hours to favor
storms moving into northern OK. As for the development of elevated
storms overnight and into Wednesday morning, the NAM has backed
off on the organized isentropic upglide over north central KS. And
as a result fails to develop any QPF. However the 01Z RAP shows
some lift with elevated CAPE across western portions of the
forecast area. CAMS remain unimpressive regarding precip chances.
And think the MCS moving south is likely to disrupt the low level
jet and isentropic fields overnight. Having said that, it is hard
to discount the RAP all together. So basically have shifted the
slight chances POPs that were already in the forecast later in the
night and into the mid morning hours Wednesday. Strong storms
with some hail potential is not out of the question with the RAP
developing over 1000 J/kg of CAPE and 0-6km bulk shear around
30KT. But this is highly conditional since confidence in storms
developing at all is on the low side.

&&

.SYNOPSIS...
Issued at 328 PM CDT Tue Aug 13 2019

The mid-level flow across the CONUS is more zonal today, with higher
pressures residing across the southern tier of the country and lower
pressures generally throughout the northern tier. 19Z water vapor
imagery showed that an area of convection was developing in western
Nebraska and northeastern Colorado near a surface low and associated
frontal boundary. Surface pressure has been slowly increasing across
the area today as a ridge axis slides into the area from the north
behind yesterday`s front. Drier air and subsidence associated with
the higher pressure was allowing dewpoints to drop and skies to
clear.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 328 PM CDT Tue Aug 13 2019

The thunderstorms forming west of the area this afternoon are
expected to develop into a cluster of storms tonight and move
southeastward into central Kansas. Some of the CAMS models are
showing precipitation clipping the western CWA overnight. The NAM
and RAP have around 1000 J/Kg of MLCAPE in central KS with weak bulk
shear as storms approach. Forcing should be limited over the CWA,
but have included a slight chance for POPs tonight in central and
north-central portions of Kansas.

Some relief from the heat and high humidity is coming for tomorrow.
Surface high pressure should dominate conditions, which will allow
for mostly sunny skies and slightly cooler temperatures. Highs
will range from near 80 degrees in northern Kansas to the mid 80s
in east-central Kansas. Dewpoints will be in the mid 60s, which
will be a noticeable improvement from recent mid 70 degree
dewpoints. Enjoy the nice day!

.LONG TERM...(Wednesday night through Tuesday)
Issued at 328 PM CDT Tue Aug 13 2019

The main challenge in the later periods is precipitation chances.
The region will be on the southern fringe of the main flow with
multiple notable shortwave moving southeast to east across the
northern CONUS. As surface high pressure pushes off to the east,
low to mid-level warm-air advection will generally increase in
depth and strength over the first few periods of this period. The
most consistent signal for northeastern portions of the state to be
under the greater convergence is Thursday night into early Friday,
though there continue to be some model differences. The jet
orientation under the WNW flow aloft could set up training cells and
bring flooding potential. There will be at least small potential
for severe wind and hail as deep shear and instability increase.
The northern wave train continues into the weekend with perhaps
the stronger forcing coming Friday night into early Saturday and
Saturday night into early Sunday and precipitation chances were
increase for these periods. There is fairly good agreement in the
upper ridge building northeast into the Rockies and northern
Plains for decreasing precipitation chances early next week. Other
than the potential for convection to persist into the middle
portions of the daytime periods, temperatures appear to be close
to normal.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday)
Issued at 603 PM CDT Tue Aug 13 2019

The RAP and NAM develop some mid level isentropic lift on the west
side of the surface ridge late tonight where forecast soundings
show good mid level saturation. In fact soundings from the NAM and
RAP across north central KS want to develop elevated CAPE values
up to 1500 J/kg. However confidence is marginal as several of the
CAMS and the GFS lack any development or shift elevated showers to
a different location. So will monitor trends and adjust as
necessary. Otherwise the surface ridge bringing relatively dry air
into the region should maintain VFR conditions.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Wolters
SYNOPSIS...Teefey
SHORT TERM...Teefey
LONG TERM...65
AVIATION...Wolters