Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/27/19

Area Forecast Discussion

National Weather Service Cleveland OH

 948 PM EDT Mon Aug 26 2019

.SYNOPSIS...
A warm front will lift north across the area tonight as low
pressure tracks east across Ontario. The low will deepen and
track to Hudson Bay Tuesday into Wednesday, forcing a cold front
east across the area. A secondary trough will move east through
the Great Lakes on Wednesday. High pressure will build northeast
across the region Wednesday night through Thursday night.

&&

.NEAR TERM /THROUGH TUESDAY/...
Update...Made small changes to pops and weather overnight into
Tuesday based on current trends and the HRRR output. Dry slot is
working into the area from the west a bit ahead of schedule but
HRRR suggests showers will also return west before dawn.


Also, for the beaches, considered a beach hazards statement but
since higher waves will be off shore tonight and Tuesday,
decided against it despite the small craft headline. Did
however boost the swimming risk to moderate Tuesday for all
beaches.


Original...Showers
continue to overspread the area this afternoon from the
southwest as a warm front lifts northeast into the area. Went
with categorical pops west/likely pops east through the evening,
with a gradual lowering of pops after midnight from west to
east as some mid level drying moves northeast into the area and
low level forcing moves out of the area. A lull in the precip
activity overnight will continue into Tuesday morning before a
cold front moves into the area during the afternoon/evening
hours. More convective showers, perhaps some thunderstorms with
weak instability building northward ahead of the front, will
overspread the area west to east after 18Z through the
evening/into the overnight. Have a corridor of high likely pops
tracking east across the area late afternoon into the overnight
hours Tuesday night. The front will push east of the area late
Tuesday night into very early Wednesday morning. Lows tonight
will be a little warmer and more humid than previous nights,
with low to mid 60s expected. Highs Tuesday will range from the
mid 70s east to the low 80s west. Low Tuesday night will be
slightly cooler and drier behind the front, with low 60s
expected.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A sharp upper level trough will be moving across the Great
Lakes Region. A decent surface high pressure system will be
building across the Midwest Region on Wednesday. The surface
gradient of low pressure over Ontario and the high pressure over
the Midwest will develop gusty westerly winds over the area
Wednesday. Westerly winds will be around the 10 to 20 mph range.
We will see a drier airmass filtering in to the area but
temperatures will be just a tad cooler and slightly below
averages. As colder air aloft at 850 to 700 mb moves over Lake
Erie, some lake effect clouds and a few lake effect showers will
be possible Wednesday evening through Thursday morning. The
upper level trough become flatten out by Thursday evening.
Another cold front will move along with the westerly mid level
flow and push through late Thursday night into Friday morning.
There may be enough lift and limited moisture to squeeze out
clouds and a few showers with the front. Another weak Canadian
high pressure builds in for Friday afternoon.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
A cooler airmass builds in Friday night with a high pressure area
coming down from Ontario. Overnight lows away from the lake will be
down in the lower to middle 50s. A shortwave will move along the 500
mb westerly flow late Saturday and Saturday night with some clouds
and a chance for scattered showers. There is some uncertain with
timing amongst the model data as the EURO is a little slower on
timing. We will continue to stay in a slight west or northwest flow
into early next week with off and on chances for clouds and a few
showers.

&&

.AVIATION /00Z Tuesday THROUGH Saturday/...
The evening begins with IFR CIGS far west and VFR conditions
east. Warm frontal showers will continue to lift north across
the area this evening as lowering CIGS drift east. While precip
will likely taper off from late evening into the early
overnight, CIGS will likely remain restricted with MVFR
visibilities in patchy fog and lingering scattered showers.
Tuesday expect continued widespread MVFR conditions. Showers and
a few thunderstorms will develop and move west to east across
the area along and ahead of a cold front.

OUTLOOK...Areas of Non-VFR Tuesday night, lingering across far
eastern OH/nw PA into Wednesday.

&&

.MARINE...
A deepening area of low pressure over the northern Great Lakes
region tonight will continue to move into Ontario overnight. A decent
low level jet will develop around 925 mb overnight into Tuesday
morning. Gusty southerly winds will develop over the lake this
evening through at least Tuesday afternoon. South winds 20 to 25
knots will be likely with wind gusts up to 35 knots possible. We
have issued Small Craft Advisories late this afternoon through early
Tuesday afternoon for these strong gusty winds. Because of the
offshore nature of the wind, waves will be generally between 1 and 3
feet. A front will move across the lake Tuesday afternoon with winds
shifting to the west 10 to 15 knots by Tuesday evening. Gusty
westerly winds increase 15 to 25 knots will develop on Wednesday and
Wednesday night with additional Small Craft Advisories likely be
needed.  Southwesterly winds will be the expected with increasing
wind speeds late Thursday and Thursday night ahead of another cold
front. Winds may increase 20 to 25 knots again and more advisories
will likely be needed again. Another front will move through on
Friday with a shift to northerly or northwesterly winds.  The main
story on the lake this week will be strong gusty winds shifting with
several fronts and building high pressure systems.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 5 PM EDT Tuesday for LEZ142>149.

&&

$$
SYNOPSIS...Greenawalt
NEAR TERM...Greenawalt/TK
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...TK
MARINE...Griffin



AREA FORECAST DISCUSSION

National Weather Service Kansas City/Pleasant Hill MO

 1035 PM CDT Mon Aug 26 2019

.Discussion...
Issued at 241 PM CDT MON AUG 26 2019

The morning/early afternoon thunderstorms that moved through eastern
KS and western MO have really altered the environment for any
potential afternoon storms. With the storms still going strong south
of the forecast area, there is a substantial cirrus shield. There is
also a lower level of stratus across east central/northeast KS and
northwestern MO that, based on satellite imagery, doesn`t appear to
be eroding with any haste. Lastly, the airmass has been
stabilized by the storms that went through and because the cloud
cover is lingering well into the afternoon, the chance to recover
and destabilize is becoming worse with every hour. With that said,
there is still strong upper level flow moving into the area
associated with an upper trough moving across the northern Plains.
This upper system will push a cold front through the area later
this afternoon and this evening. With the forcing associated with
the front and upper-level shortwave, we should still be able to
see scattered to maybe widespread showers and few storms develop.
But the lack of instability should keep the severe weather
chances lower and really confined to areas south of Highway 50, or
even south of the forecast area. The RAP and the HRRR, which
finally started to resolve the MCS, show the far southern portions
of the forecast area building instability as the front moves into
that area around 23Z this afternoon. 19Z observations show very
warm temperatures and dewpoints in southeastern KS and
southwestern MO. So there isn`t a great distance from weak
instability to extreme instability. A little northward advection
of this and it`s in the southern portions of the forecast area,
like the RAP and the HRRR show. Given this, can`t rule out a
severe storm in our far southern counties later this afternoon or
early this evening as the front is moving through.

Dry weather with cooler than normal temperatures is expected through
at least Thursday. Thunderstorm chances return Friday as a surface
boundary stalls in the area and a mid-level shortwave moves east
across KS. Those chances may linger into Saturday but by Sunday into
Monday, it looks like we are back into the cooler, drier weather
pattern prevails again.

&&

.Aviation...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1032 PM CDT MON AUG 26 2019

A cold front has pushed through the area and cleared out the area
of the MVFR ceilings. This has created clear skies with light
winds and dropping temperatures, but not dropping dewpoints. Due
to this we are going to see a few hours of fog potential over the
region before the drier dewpoints upstream in Nebraska can make
their way into the area around 09Z. I`ve added some MVFR
visibility to account for this with some LIFR visibility around
KSTJ as they tend to go down quickly with the warmer Missouri
River nearby. Once these drier conditions make their way into the
area things should stay VFR from there.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

Discussion...CDB
Aviation...Barham



Area Forecast Discussion

National Weather Service Green Bay WI

 1054 PM CDT Mon Aug 26 2019

Updated aviation portion for 06Z TAF issuance

.SYNOPSIS...
Issued at 227 PM CDT Mon Aug 26 2019

Showers continuing tonight, then a couple days of blustery weather
mid-week. Quieter conditions will settle into the area for the
end of the week and start of the Labor Day weekend.

Large scale amplification will continue the next few days as the
upper trough progressing into the region deepens and closes off
into an upper low over western Ontario. The upper flow will
flatten later in the week as the bulk of the energy within the
trough lifts into northeast Canada. That will result in rising
upper heights and a weakening of the cyclonic upper flow across
the area.

The ongoing precipitation event will account for the bulk of the
precipitation that occurs during the period. After that moisture
will be limited, so subsequent precipitation events will likely
generate scattered light to moderate amounts. Totals for the whole
period will probably be near to slightly below normal. A few days
ago, it seemed that generally below normal temperatures would be
likely after today. It now appears there will be more significant
day-to-day variation (cool Wednesday, warmer Thursday, then
cooler again Friday and Saturday). It still appears as though
readings will probably end up near of slightly below normal for
the period as a whole.
&&

.SHORT TERM...Tonight and Tuesday
Issued at 227 PM CDT Mon Aug 26 2019

The latest RAP analysis and satellite/radar imagery show an area
of low pressure over northwest Illinois, and an associated warm
front extending east across northern Indiana. Several embedded
shortwave impulses are sliding north into the region ahead of the
low and generating widespread light to moderate rain over much of
eastern WI. Meanwhile, a cold front is moving east across
Minnesota, with another band of showers and isolated storms along
it. As these systems move across the region, precip trends and the
possibility of strong storms on Tuesday afternoon are the main
forecast concerns.

Tonight...The low pressure currently over northwest Illinois will
lift northeast and across northeast WI this evening. The main area
of rain will continue to shift with the low and exit far
northeast WI by midnight. Not out of the question that a rumble
of thunder could impact the lakeshore areas until that time, as
there are decent radar returns offshore of Sheboygan. With pwats
upwards of 1.8 inches, the rainfall will likely be quite efficient
and could therefore look at precip totals upwards of 1 inch at
some areas. Looking to the west, a solid band of rain will be
heading east across the state ahead of a cold front. Most models
have this rain band thinning out as it approaches north- central
WI by mid- evening. This makes sense in that the forcing via mid-
level fgen will weaken as it lifts north into Lake Superior.
Elevated instability also is projected to weaken at the same time.
Otherwise, should see a cloudy night with lows not falling much
into the upper 50s to lower 60s.

Tuesday...Winds will turn to the west behind the cold front and
becoming gusty during the morning. The influx of drier air and
downsloping should lead to partial clearing over eastern WI first
during the morning, while north-central WI will be slower to
clear. With upper troughing over the northwest part of the state,
a potent shortwave will move into Wisconsin during the afternoon.
Steepening mid-level and low level lapse rates will result in
instability growing to above 500 j/kg in the mixed layer. If it
weren`t for the lack of moisture through the column, storms would
be a higher bet. Will show storm chances spreading from northwest
to southeast through the afternoon. Given the cool temps aloft,
could see some brief gusty winds and small hail in any storms.
Temps returning to the upper 60s to mid 70s.

.LONG TERM...Tuesday Night Through Monday
Issued at 227 PM CDT Mon Aug 26 2019

Relatively deep mixing into unidirectional westerly flow will
result in gusty winds and blustery conditions during the daytime
on Wednesday. Periods of showers are likely mid-week as shortwaves
rotate through the area. Although those will be difficult to
time, there should also be a diurnal component to the showers so
adjusted PoPs and Sky grids with that in mind. A more substantial
shortwave pushing across southern Canada mid-week will likely
generate a surface reflection. Southwest winds ahead of that
feature will bring milder air into the area, resulting in a warmer
day on Thursday. Cooler air will settle into the area in the wake
of the feature and linger into the start of the weekend as an
anticyclone from southwest Canada settles into the region.

Overall, the default forecast initialization grids based on a
broad-based blend of guidance products seemed reasonable. Some
adjustments were made to PoPs and Sky grids for the first few days
of the long-term portion of the forecast to account for
clouds/showers expected to shift across the area as shortwaves
rotate around the base of the deepening upper trough.
&&

.AVIATION...for 06Z TAF Issuance
Issued at 1054 PM CDT Mon Aug 26 2019

IFR conditions will continue overnight as a low pressure system
continues to bring rain showers to the area as a cold front slides
through the area. Behind the cold front, slowly improving cigs
are likely over the Fox Valley and Lakeshore late tonight, but
central and north-central WI areas may have to wait until Tuesday
morning for the improving conditions. With partial clearing, gusty
west winds are expected to develop by midday Tuesday, with more
storms possible on Tuesday afternoon. The best chance for storms
Tuesday afternoon will be across north-central and central
Wisconsin. Farther east the chances are too low to include in
this set of TAFs.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement until 7 AM CDT Tuesday for WIZ022-040-
050.
&&

$$

SYNOPSIS.......Skowronski
SHORT TERM.....MPC
LONG TERM......Skowronski
AVIATION.......Kurimski



Area Forecast Discussion

National Weather Service Grand Rapids MI

 1034 PM EDT Mon Aug 26 2019

LATEST UPDATE...
Update

.SYNOPSIS...
Issued at 330 PM EDT Mon Aug 26 2019

-Rain showers tonight into Tuesday morning

-Dangerous swim conditions Tuesday, worse Wednesday

-Beach erosion and lakeshore flooding possible Wednesday

-Temperature mostly below normal through Labor day

&&

.UPDATE...
Issued at 1035 PM EDT Mon Aug 26 2019

Little question it will continue to rain across the area through
midnight or so. However based on SPC Mesoscale Analysis at 10 pm,
there clearly is very little instability for thunderstorms.
Monitoring our radar echos near the -10c isotherm, none of the
echos that reach that level have been strong enough for lighting
production. Since the 9 pm run of the RAP model had the most
unstable cape below 200 j/kg as the upper wave tracks across our
CWA and we are in the right exit region of the incoming upper jet,
all of these things tell me thunderstorms are rather unlikely. So
I have taken them for the most part out of the forecast. I did
leave a small chance near I-94 for a few hours just in case.

Otherwise the on-going forecast is doing nicely. Most of the rain
should be east of our CWA by 2 - 3 AM this morning.



&&

.DISCUSSION...(This evening through next Monday)
Issued at 330 PM EDT Mon Aug 26 2019

Showers expected to become more numerous this evening as negative
tilt shortwave lifts northeast from nrn Illinois. Can`t rule out
an isolated tstm tonight, but not much lighting has been noted
upstream today and cape progs are not impressive. The RAP and NAM
do however show 600-800 J/KG capes after midnight.

Although an extremely low probability scenario, it should be
noted that a brief spin up tornado or two cannot be ruled out
tonight. Tremendous low level wind shear exists thanks to backed
/southeasterly/ sfc flow and increasing SSWly low level just above
the sfc. If any sfc based instability can sneak into Southwest
Michigan tonight it`s possible that even a rain shower could drop
a quick, weak tornado. best time frame would be 00Z to 06Z, but
again this is a really low possibility.

Also still can`t rule out some locally heavy rainfall amounts of
up to two inches tonight, although confidence in that is low since
model qpfs have trended down a bit.

Looks like we dry out Tuesday afternoon and sunshine emerges as
dry slot sweeps in from the west, although perhaps some gusty
winds to 25 mph developing once deeper mixing develops. We may
flirt with 80 degrees, especially from GRR south and east, since
the good cold advection holds off until late Tuesday night-Wed.

Cooler and breezy as main upper trough arrives late Tuesday night
and Wednesday. This should also lead to increasing cloudiness
with some isolated showers possible.

We begin warm advecting again on Thursday, then another cold front
brings a chance of rain on Thursday night. Cooler than normal
temps expected as we move into Labor Day weekend but only low
precipitation probabilities at this point. Latest ECMWF wants to
generate some rain on Sunday south of I-96 as a wave moves along
the sfc front which will be south of MI.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 745 PM EDT Mon Aug 26 2019

Expect for the most part IFR conditions through 12z as the
frontal system moves through the area. There is a large area of
IFR cigs over most of central and southern Lower Michigan at 00z
that extends south into Ohio and eastern and central Indiana.
There is also a band of convection moving east over Lake Michigan
that will move through all of the TAF sites in the 01z to 06z
time frame with rain that may be heavy at times. Surface winds
will remain gusty until the back edge of the rain band moves
through and winds will be lighter and more from the south.

The cold front will come through during the mid morning hours and
may have a few showers with it. After it comes through winds will
turn more westerly and skies will clear rather quickly.


&&

.MARINE...
Issued at 330 PM EDT Mon Aug 26 2019

Have extended beach hazard statements and small craft advisories
into Wednesday, which looks like the worse of the next two days.
In fact we may also need lakeshore flood advisories for wednesday
to highlight the high risk of beach erosion. Current strong
southeast flow goes southerly tonight then west-southwest for
Tuesday. The flow on Wednesday will be westerly which is a prime
direction for some erosion issues with waves near 8 feet forecast.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 6 AM EDT Tuesday through Wednesday
     evening for MIZ064-071.

     Beach Hazards Statement through Wednesday evening for MIZ037-043-
     050-056.

LM...Small Craft Advisory until 8 PM EDT Wednesday for LMZ844>849.

&&

$$

UPDATE...WDM
SYNOPSIS...Meade
DISCUSSION...Meade
AVIATION...WDM
MARINE...Meade




Area Forecast Discussion

National Weather Service Chicago/Romeoville, IL

 943 PM CDT Mon Aug 26 2019

.UPDATE...
943 PM CDT

Showers and isolated t-storms have generally pushed south and east
of our CWA as of mid evening. Can`t rule out an isolated shower or
two the rest of tonight, especially far southern CWA, as the main
upper trough moves through the region, however guidance has
largely trended dry tonight. In addition, DVN sounding this
evening confirmed what GOES water vapor imagery depicts, and that
is an abundance of dry air in the mid-upper levels. Given this
data, have removed precip chances over most of the CWA for the
remainder of tonight, the one exception being very far southern
portion of the area where I hung on to some chance pops in case
some showers develop northward as weak shortwave trough in MO
moves eastward.

- Izzi

&&

.SHORT TERM...
235 PM CDT

Through this afternoon...

Showers have expanded in coverage early this afternoon as a
surface circulation tracks northeast across north-central
Illinois. This has pushed a warm frontal boundary further north
into the area. Low level instability is maximized ahead of the
surface low with decent low level shear in place as well. Some of
the better organized showers have exhibited some weak low level
rotation across Kane Co. which may be due to somewhat better low
level convergence with south-southeast winds across much of the
Chicago metro. Better overall instability is to the south and
supportive of stronger updrafts but low level convergence is less
favorable. Best potential for lightning is to the south. A low
chance for an isolated funnel or perhaps brief tornado is probably
between the I-80 and I-90 corridors with somewhat deeper showers
but this chance is pretty minimal. Decent rainfall is also
occurring with the very moist airmass with radar estimates of
around 0.5 in/hr with some isolated amounts closer to 0.75-1.0/hr
likely occurring. The bulk of the activity should exit to the
east and northeast late this afternoon.

MDB

&&

.LONG TERM...
235 PM CDT

Tonight through Monday...

The second of two shortwaves embedded within the larger scale
cyclonic flow aloft will be approaching the area this evening then
gradually swinging through overnight.  Presently the activity
associated with this wave is focused in two different areas.  To the
north and closer to a surface low over Manitoba is a line of
convection along a cold front pushing through Minnesota and northern
Iowa.  Farther south near another low center, or more of a meso-low,
over Missouri is a line of stronger convection that dropped out of
Nebraska and is moving southeast.  In between, the low level
convergence appears much more marginal.  It is possible that
portions of the forecast area will not see additional showers and
thunderstorms as the frontal zone moves through tonight.  This is
actually the scenario depicted by the HRRR which seems to be
handling the existing activity reasonably well and favors southern
portions of the forecast area as being most likely to see later
development.  All of this thinking appears to align with existing
forecast trends which show a break in activity toward early evening
and then an uptick overnight and into the predawn hours Tuesday,
mainly south.

Tuesday morning the cold front pushes off to our east which should
bring an end to any lingering shower activity.  High pressure then
settles in at the surface and keeps a lid on additional development
until late in the week.  The exception could be Wednesday afternoon
when the longwave trough axis pushes through overhead and low levels
become well mixed on the northeast periphery of the surface high.
The GFS and ECMWF both hint at some afternoon showers just to our
north, farther from the influence of the ridge, but forecast
soundings over the local area suggest development would be limited
to the boundary layer.  Even so, both Wednesday and Thursday appear
to be well mixed at the surface and tapping into some stronger gust
potential from 20+ knot westerlies just above the boundary layer.

Confidence decreases from late week into the holiday weekend, though
deterministic NAM/GFS/ECMWF solutions all agree in pushing the next
frontal zone toward the region by late Thursday or more so into
Thursday night.  Ahead of this feature, Thursday appears to be the
warmest and most humid day of the week, though heat indices only top
out in the low to mid 80s. The GFS/ECMWF then drop the front south
of the area for the late week and early weekend with another high
settling overhead. If it drops far enough south, this would bring a
brief period of showers or thunderstorms on Thursday night then keep
at least Friday and the early part of Saturday dry. However, if the
front stalls just to our south and lifts north again later on Friday
into Saturday it would be the focus for ongoing development during
this period. Specifics are too uncertain to pin down at this range,
though it does appear the position of this boundary will be one of
the keys to monitor for the weekend.  Until things are more clear,
plan to carry chances of precip both Friday and Saturday, with the
late weekend drier for now.

MDB

&&

.AVIATION...
For the 00Z TAFs...

707 PM...Forecast concerns include...

Scattered showers this evening.
Mvfr cigs through Tuesday morning.
Possible ifr cigs/fog overnight.
Gusty westerly winds Tuesday.

Scattered showers will continue across the terminals this evening
with briefly lower vis into mvfr. Not expecting any thunder with
this activity. Any additional showers or isolated thunderstorms
later tonight are expected to remain well south of the terminals.
There may also be a few showers Tuesday afternoon but expected
coverage will be isolated.

Cigs have remained generally vfr with some patchy mvfr through
late afternoon but are expected to trend into mvfr this evening
and lower to low mvfr overnight with ifr possible. But confidence
for ifr cigs is low and have only included scattered mention for
ord/mdw. Cigs will lift through mvfr Tuesday morning with a low
vfr deck expected Tuesday.

West/southwest winds 10-15kts with higher gusts will continue this
evening and slowly diminish overnight. Winds will turn more west/
northwest Tuesday morning with speeds increasing and gusts to
20kts possible for the afternoon. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&

$$

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Area Forecast Discussion

National Weather Service Memphis TN

 918 PM CDT Mon Aug 26 2019

.UPDATE...

A lull in convection is occurring the Mid-South at this time. Some
clearing has occurred over portions of the area which may lead to
some fog development. After midnight, convection that is currently
occurring along the I-44 corridor in Missouri will begin to push
into Northeast Arkansas. The convection may be moving into the
Memphis Metro area around sunrise. Have adjusted POPS for the
overnight into the morning and added mention of fog. Rest of
forecast looks good.

KRM

&&

.DISCUSSION... /issued 344 PM CDT Mon Aug 26 2019/

An unseasonably deep upper low will lift from southern Manitoba
to northern Quebec this week. This feature will remain
sufficiently broad to result in northwest aloft across the
Midsouth, which will aid in a surface cold frontal passage late
tonight. No significant cooldown associated with this front, but
drier air (dewpoints in the upper 50s to mid 60s) will begin
spreading into the Midsouth late Tuesday, and persist into late
week. The drier air will allow for overnight lows to cool as the
low as the upper 50s in the valleys near the TN River.

In the interim, short term convective trends remain the primary
forecast challenge. Midafternoon regional radar mosaic showed a semi-
linear cluster of storms dropping into southern MO, well ahead of
the short term convection-allowing model (CAM) guidance. The 19Z
HRRR model finally initialized the position of the MCS, but
depicted the storms dissipating over southeast MO by 00Z/7PM CDT.
SPC Mesoanalysis showed less instability and weaker shear toward
the MO bootheel at 20Z, but no so much as to preclude thunderstorms.
Reality may lie somewhere in between, with loss of surface
heating resulting in stronger capping and storm dissipation over
northeast AR toward midevening. Afternoon forecast package relies
less on short term CAM guidance and more on extrapolated convective
trends.

For the overnight, attention remains on eastern KS for early
evening convective-initiation. This area is where CAM consensus
generates an additional MCS, fed by a post-sunset 35kt low level
jet. Resultant storms would move southeast into AR and perhaps
west TN through sunrise. This secondary MCS would have a synoptic
cold front on which to focus convection initially. This front had
just exited the southeast corner of Nebraska at 3PM CDT today.

The front will likely slow over north MS Tuesday, where dewpoint
pooling and surface heating will provide a chance of storms.
Thereafter, an extended dry period is forecast through Saturday.

An upper level ridge building in from the southern plains will
bring warmer and predominately dry weather to the Midsouth on
Labor day, toward the middle of next week.

PWB

&&

.AVIATION...

00Z TAfs

Confidence growing that convection in southern Missouri will
weaken over the next couple of hours while a new line develops
farther back along an approaching cold front. This new line will
affect the sites later in the period so timing of convection has
been adjusted. VFR to start but conditions will drop to MVFR and
IFR. Before convection fog may form at MKL and TUP with possible
LIFR. Showers taper off late with VFR cigs. Light south winds
veering westerly late. Higher gusts near T-storms.

JAB

&&


&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

$$



Area Forecast Discussion...UPDATED

National Weather Service Mobile AL

 939 PM CDT Mon Aug 26 2019

.DISCUSSION...See updated information for land areas below.

&&

.UPDATE...Current forcast has been updated to reflect current
downtrend in precipitation coverage over the forecast area. Latest
guidance still advertising an increase in rain coverage after 06Z
as a piece of shortwave energy moves through an upper trough
stretching ssw across the region. With limited instability, have
cut back on the rumbles in the weather from previous forecast.
Temperatures are on track, so no adjustments needed there. Updates
out shortly. /16

&&

.PREV DISCUSSION... /issued 644 PM CDT Mon Aug 26 2019/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
00Z issuance...General mid-MVFR and VFR conditions were observed
across the forecast area at 23z, with rain covering most of the
area. Local drops to IFR or lower in the heavier rain over areas
east of the Alabama River were also noted. As the forecast
progresses into the evening, rain coverage will continue to
decrease in strength and coverage, though abundant mid/upper level
cloud will help to limit fog formation and low end MVFR or lower
VISBYs through the overnight hours. Southerly winds of 5 to 10
knots are expected to last through the night.

Tuesday, showers are expected to develop close to sunrise, and
become thunderstorms late morning into the afternoon. MVFR
conditions are expected to start the day, becoming general VFR,
with local MVFR in the convection. Southerly winds around 10 knots
are expected during the day.
/16

PREV DISCUSSION... /issued 400 PM CDT Mon Aug 26 2019/

NEAR TERM /Now Through Tuesday/...Upper-level energy and the
deep plume of tropical moisture previously located off the SW
Louisiana coast has triggered widespread convection as it moved
over the area today. Convection is expected to gradually diminish
in the evening to late night hours as the airmass stabilizes and
the main forcing for ascent eventually shifts east. The HRRR
projects the last robust band of convection now moving eastward
into SW MS to move eastward through SE MS by early evening and
across S AL and NW Florida during the evening to a little after
midnight. Weak troughing aloft remains over the area tomorrow with
elevated PWATS of 2 to 2.25". Expect scattered to numerous
showers and thunderstorms to again develop with surface heating
and low level lift courtesy of the lingering outflow boundaries
generated by today`s convection. Breaks in cloud cover tomorrow
should allow daytime temperatures to climb into the upper 80s to
lower 90s. /08

SHORT TERM /Tuesday night Through Thursday night/...As stability
increases during the evening hours convection will decrease with
only a slight chance of thunderstorms expected across most of the
area. A chance will remain along the coast as storms are expected
to continue to form over the warm Gulf waters overnight and
potentially move over coastal areas before dissipating.

A cold front approaches from the northwest and pushes southward
across the area Wednesday and moves out over the Gulf Wednesday
night. Scattered to numerous showers and thunderstorms develop
during the day along and ahead of this boundary shifting south
over the marine area during the evening hours. A drier, northerly
flow will follow in the wake of this system. Cooler overnight lows
anticipated Wednesday night, falling into the mid 60s to near 70
over northern inland locations and low to mid 70s closer to the
coast.

A drier airmass settles over the area through Thursday night and
subsidence from the low and mid-level ridge over the region
should suppress the development of convection. The lack of showers
and sunny skies will allow temperatures Thursday afternoon to
climb to around 90 and possibly into the mid 90s. Fair skies and
drier air Thursday night will lead to relatively cool overnight
lows...low to mid 60s inland to upper 60s low 70s closer to the
coast and mid 70s along the immediate coast. /08

LONG TERM /Friday Through Monday/...A moist low level return
flow starts to develop late Friday as surface high pressure to the
north shifts eastward into the western Atlantic. By Saturday deep
layer moisture starts to pool over the region as onshore flow
increases and the region lies in between the ridge aloft to the
east and west. Diurnally driven afternoon convection is expected
to begin Saturday and continue into Monday. Temperatures are
forecast to trend near to a little warmer than climatological
norms.

In the tropics, Tropical Storm Dorian is forecast by the National
Hurricane Center (NHC) to impact the Lesser Antilles tonight and
tomorrow and then follow a northwestward track and move in the
vicinity of the Bahamas by this weekend. There still remains a
great deal uncertainty and inconsistencies among the models on
how this system will evolve and the track it will take through the
week. We will continue to monitor the evolution of Dorian closely
and provide updates as needed. /08

MARINE...A light to moderate onshore flow will continue through
Tuesday night with an offshore flow developing Wednesday and becoming
easterly by this weekend. Periods of scattered to numerous
thunderstorm activity are expected through Wednesday. A weak cold
front will approach from the north and move southward across the Gulf
Wednesday night. Shower and thunderstorm activity will decrease
following its passage but will return to the marine area this
weekend. /08

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&

$$

This product is also available on the web at:
http://weather.gov/mob




Area Forecast Discussion

National Weather Service Paducah KY

 1100 PM CDT Mon Aug 26 2019

.UPDATE...
Issued at 1100 PM CDT Mon Aug 26 2019

Updated aviation discussion.

&&

UPDATE...
Issued at 921 PM CDT Mon Aug 26 2019

The next round of convection is already firing up over central
Missouri. The latest HRRR output is too slow and likely too
intense, but the 00Z WRF runs seem reasonable for the more
organized convection just after 06Z. Figure the thunder will be
focused over southeast Missouri, with the best chance of severe
winds running along the southwest edge of this afternoon`s
storms. Still expecting a weakening, if not dissipating, trend as
it moves farther east into the area. The Ft Campbell area may not
get wet at all.

&&

.SHORT TERM...(Tonight through Tuesday night)
Issued at 237 PM CDT Mon Aug 26 2019

MCS over south central MO moving ESE at 45 mph. None of the models
handled this activity at all. So needless to say our PoPs are
geared toward reality. The area should enter southeast MO from
4 to 430 PM. How far east it makes it is very much in question.
Given mesoscale trends, would not be surprised if it continues
into southern IL and west KY for finally winding down a bit. There
is a chance of severe thunderstorms mainly over southeast MO. The
airmass is unstable and the activity is being supported by a
40-50kt mid level wind max. After this activity is no longer a
factor, the convective allowing models continue to show more
activity later tonight with the front, with chances continuing
into Tuesday morning, ending in the afternoon across the KY
Pennyrile region. Temps will be a blend of existing numbers and
the latest NBM output.

.LONG TERM...(Wednesday through Monday)
Issued at 237 PM CDT Mon Aug 26 2019

Although not depicted properly early on by the NBM (National Blend
of Model) guidance, the NBM has finally settled on a dry solution
for the latter half of the week and into the weekend for the WFO PAH
forecast area.

Most of the numerical model suite keeps the local forecast area of
the influence of High Pressure through Friday, with another surge of
high pressure building into the area over the weekend.

The lack of deep layer moisture across the area, combined with a
flattening of the eastern Canada/Hudson Bay trough, will definitely
keep the WFO PAH forecast area dry through Friday.  The preferred
CMCnh (Canadian) guidance does sharpen the trough over the Middle
Mississippi Valley Saturday night into Sunday, but moisture is
lacking over the area during this time, so the potential for
measurable PoPs is quite limited.  Hesitated to drop PoPs for
Saturday, given the small potential entered in previous forecasts.
However, given the limited PoP potential to begin with, opted to
keep a dry forecast in place with this forecast package.

Will be interesting to see if T.S. Dorian has any impact beyond this
forecast period per medium range model guidance solutions. Will
monitor official NHC forecasts for trends.

&&

.AVIATION...
Issued at 1100 PM CDT Mon Aug 26 2019

Overnight, winds are forecast to return to southerly at less than 12
knots sustained, as more shower and tstm activity associated with a
cold front moves in from the west. Toward daybreak and into Tue
morning, MVFR cigs are likely across the region, with some
flirtations with IFR. Under stronger showers/tstms, brief IFR vsbys
are possible, otherwise vsbys should be VFR most of the time. Winds
are expected to begin a turn to the northwest after daybreak Tue,
with the wind shift progressing northwest to southeast. Scattered
shower and tstm activity will diminish and sky conditions will
improve with the wind shift during the day Tue.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&

$$

UPDATE...DRS
AVIATION...DB



Area Forecast Discussion

National Weather Service Topeka KS

 808 PM CDT Mon Aug 26 2019

.UPDATE...
Issued at 800 PM CDT Mon Aug 26 2019

With the H850 trough having passed through the area, the threat
for thunderstorms has shifted south and east of the forecast area.
Have removed mention of storms from the grids and products. Fog
threat seems very limited in scope and coverage given the 2-4 mb
pressure difference across the forecast area through the overnight
hours and ongoing negative theta-e advection. Winds at the top of
the very shallow BL inversion should remain in the 10 to 15 kt
range, which should help keep the airmass mixed enough to hinder
fog formation.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 332 PM CDT Mon Aug 26 2019

A surface cold front is moving eastward across the forecast area
this afternoon. As of 20Z, the front was located from around
Hiawatha to just east of Manhattan to near Council Grove.
Thunderstorms will likely develop along the front, but there remains
some uncertainty as to exactly where and when storms will
initiate. This morning`s convection left an area of cloud cover
over the region and expected instability has not been realized so
far today. The HRRR now confines the best surface based
instability to areas along and southeast of I-35, where the model
shows over 3000 J/Kg of CAPE with no inhibition at 21/22Z ahead of
the front. The RAP has also started to trend southward with the
best dynamics for thunderstorms, which makes sense given the
location of the outflow from earlier activity. As such, it looks
like the most likely area for thunderstorm activity this afternoon
will be along and south of I-35. The front will clear the area by
around 00/01Z, taking storms with it.

A few gusty winds will be possible just behind the front with a
tight pressure gradient in place. Surface ridging will commence
following fropa, and winds will quickly relax by this evening. Drier
air will move in tonight with dewpoints dropping into the upper 50s
north of I-70 by sunrise Tuesday. With light winds, clearing skies
and dewpoint depressions of only a few degrees, patchy fog will be
possible by early tomorrow morning, especially in areas that
received rainfall this morning and areas that receive rainfall
this afternoon.

Higher pressure will continue to work into the area tomorrow with
the center of the surface high located directly over central KS by
Tuesday night. Temperatures will only warm to near 80 degrees under
sunny skies, making for very enjoyable conditions tomorrow
afternoon.

.LONG TERM...(Tuesday night through Monday)
Issued at 332 PM CDT Mon Aug 26 2019

High pressure will stay in control of our conditions through
midweek before it begins to move southeast of the region on
Thursday. Southerly winds on the back side of the surface ridge
will begin to advect moister and warmer conditions into the CWA on
Thursday. The next chance for rain and storms appears to be late
Thursday or early Friday when the next front is forecast to move
into northeastern portions of Kansas. A more active pattern could
persist into early next weekend so will monitor those trends
through the week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 640 PM CDT Mon Aug 26 2019

MVFR stratus clears from northwest to southeast this evening, with
no restrictions expected tonight or on Tuesday. Winds will be from
the north to northwest at 5 to 10 kts.


&&

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

$$

UPDATE...Skow
SHORT TERM...Teefey
LONG TERM...Teefey
AVIATION...Skow