Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/09/17

Area Forecast Discussion

National Weather Service Albany NY

 1048 PM EDT Fri Sep 8 2017

.SYNOPSIS...
An upper level low pressure area will remain located
over the region through tonight. The weather will improve over the
weekend with a drying trend and moderating temperatures. Pleasant
weather is expected to start next week with mild temperatures and
plenty of sunshine.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 1040 PM EDT, latest GOES-16 IR imagery shows the area
under mostly clear skies. This has allowed for patchy fog to
develop with varying visibilities down to less than a mile at
times. Trends will have to be monitored overnight for potential
dense fog development. Please use caution if traveling as
sudden changes in visibilities are possible.

Prev Disc...
As of 740 PM EDT, scattered showers are beginning
to wane with loss of daytime heating. Expect this waning trend
to continue for the next hour or so, leading to a mostly dry
night for the forecast area. Latest GOES-16 IR imagery shows
variable cloud cover across the area, with the Adirondacks and
Lake George- Saratoga regions being impacted the most by cloud
cover. Locations south and east of the Capital District should
see a decrease in cloud cover this evening which may lead to
some fog development. So have added in patchy fog to the
forecast tonight. Otherwise, freshened up the hourly temps and
sent updates to NDFD and web servers.

Prev Disc...
As of 330 PM EDT...A sharp and deep upper level trough
continues to be situated over the region. 500 hpa temps off the
18z KALY sounding were very chilly, around -22 degrees C, which
is close to the minimum value seen on the SPC Sounding
Climatology page.

With the chilly temps aloft and cyclonic flow in place,
scattered showers have developed across the region, especially
for northern areas. 18Z KALY sounding shows around 600 J/kg of
sfc-based CAPE in place, so cannot rule out a few stray
t-storms, although storms won`t be able to get too tall at all
due to the low EL. Will continue to mention the possibility of
small hail within any thunderstorm due to good low and mid level
lapse rates (close to 7 deg/km) and low freezing levels. As the
trough shifts eastward, showers and possible thunderstorms will
gradually shift south and east through the remainder of the
afternoon and into the early evening hours.

By this evening, showers will start to diminish in coverage due
to the loss of daytime heating. The 3km HRRR suggest showers
should completely be done by about midnight. There may be some
breaks in the clouds by late in the overnight, especially for
valley areas. This could allow for some patchy fog to develop,
especially for areas that see any rainfall today or around
lakes/rivers. Overnight lows look to be in the 40s.

On Saturday, the shortwave trough will be shifting eastward
across New England. Still cannot totally rule out a stray shower
for northern or eastern areas (mainly early in the day), but
most areas look to stay dry with a partly to mostly cloudy sky
in place. Highs will be in the mid to upper 60s for valley
areas, with upper 50s to low 60s across the hills and mountains.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Pesky upper trough axis will be sliding eastward Saturday night
with residual cloud coverage during the evening hours. As those
clouds dissipate, with a light northerly wind, temperatures
will remain a bit cool with mainly 40s across the region (some
upper 30s across the Dacks).

Then a developing big bubble no trouble as we find ourselves
between a developing low across the North Atlantic and remnants
of Irma across the Tennessee/Lower-Ohio Valleys. Compressional
warming thanks to increase subsidence around these systems will
result in mainly clear skies and milder daytime temperatures as
H850 climb into the mid teens celsius.

Some radiation fog will be possible in usual locations each
night in the short term period. Lows will be mainly in the 40s
with daytime highs climbing well into the 70s Monday.

Please refer to the latest forecast on the tropics from the
National Hurricane Center (www.hurricanes.gov).

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The long term period will feature mostly dry conditions with
seasonable temperatures. To start, high pressure resides at the
surface and aloft over the Great Lakes Region Monday night into
Tuesday. Models show that heights associated with this high are 1 to
2 standard deviations above normal, which will help block Irma while
it shifts to the west (instead of lifting northeast). This ridge
will provide abundant sunshine and dry weather through Tuesday with
850 mb temps in the +14C to +16C range. High temperatures on Tuesday
will generally be in the 70s with valley locations potentially
warming towards the 80 degree mark. Good radiational cooling at
night will allow for temperatures to dip into the 40s and 50s.

Tuesday night through Friday...remnant moisture and energy from Irma
slowly expands northward as a strong upper trof over southeastern
Canada and surface cold front slide through the forecast area. These
features have slowed down some and are now expected to move through
our area sometime late Wednesday into Thursday morning. Some of the
deeper moisture from Irma may make it into the southern half of the
region and interact with the upper trof but the cold front appears
to be fairly moisture starved. Therefore, have limited rain chances
mainly to southeastern New York Wed night/Thursday morning, with
slight chances north of the Capital District. Dry air and surface
high pressure build back into the area behind the frontal passage,
setting the stage for a nice end to the work week.

High temperatures Wednesday through Friday should reach the 60s
across the high terrain and into the low 70s for valley locations.
Overnight lows will generally be in the 40s and lower 50s each
night.

Please refer to the National Hurricane Center for the official
forecast and track of Hurricane Irma (www.hurricanes.gov).

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Afternoon shower activity will continue to wane over the next
hour or so, leading to a mostly dry VFR forecast for all the
TAF sites. Sky cover is bit tricky overnight with scattered to
broken 4-6kt clouds in place. Wherever there are some breaks in
the clouds, some fog development may be possible. So have
included the mention of BR across all TAF sites, with IFR fog at
KPSF.

During the day on Saturday, broken CIGS will be around 4 kft
for all sites with VFR conditions. NW winds will be around 5-10
kts. There could be a stray rain showers around KGFL but most
other areas should remain dry through the entire day.

Outlook...

Saturday Night to Wednesday: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
An upper level low pressure area will remain located
over the region through tonight with scattered showers. The
weather will improve over the weekend with a drying trend and
moderating temperatures. Pleasant weather is expected to start
next week with mild temperatures and plenty of sunshine.

Maximum relative humidity values will be increasing to values
at or above 90 percent tonight. RH values will drop to around
50 to 65 percent Saturday afternoon.

Winds tonight through Saturday will be northwest around 5 to 10
mph with a few higher gusts Saturday.

&&

.HYDROLOGY...
No hydrologic problems are anticipated through the middle of next
week.

Scattered showers and isolated thunderstorms through this
evening, which could produce some brief downpours. Basin
average rainfall will be light and have no impact on rivers and
streams. Total rainfall amounts through Saturday will be under a
quarter of an inch.

With high pressure moving into the area thereafter, dry weather
is expected for Saturday night through Tuesday. As a result,
river and streams levels are expected to hold steady into next
week.

For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$
SYNOPSIS...Frugis/JVM
NEAR TERM...Frugis/JVM
SHORT TERM...BGM
LONG TERM...JVM/Wasula
AVIATION...Frugis/JVM
FIRE WEATHER...BGM
HYDROLOGY...BGM




Area Forecast Discussion

National Weather Service Bismarck ND

 940 PM CDT Fri Sep 8 2017

.UPDATE...
Issued at 929 PM CDT Fri Sep 8 2017

Clear skies and a southeast flow will continue through the
overnight hours. Overnight lows mainly in the 50s. Current
forecast is on track.

UPDATE Issued at 634 PM CDT Fri Sep 8 2017

Mostly clear but hazy conditions are expected this evening with a
moderate southeast surface flow. No changes for the early evening
update other than populating latest sensible weather elements and
interpolating to mid evening values.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 246 PM CDT Fri Sep 8 2017

Latest visible satellite imagery shows a generally clear sky. Some
high clouds evident along with a narrow corridor of haze/smoke
across portions of central ND. Low level southeasterly flow was
occurring across western and central ND, strongest in southwest
ND this afternoon with winds between 15 and 25 mph. Southeast flow
will advect moisture/higher dewpoints from South Dakota into
mainly south central ND overnight. Have collaborated/coordinated
with Aberdeen Forecast Office and followed a National Blend Sky
Coverage in conjunction with the HRRR Experimental Visibility/Low
Cloud forecast. Not expecting any widespread fog/stratus at this
time. Ashley, Bismarck, and Jamestown BUFKIT soundings indicate
saturation is less than and not as deep as we experienced early
this morning. Enough Omega/upward vertical motion in the lower
levels to keep the atmosphere more unstable overnight, with less
fog development, thus patchy.

The latest water vapor imagery shows an upper low circulating along
the southwest ND/northwest SD border. Little in the way of clouds
or deep moisture per GOES16 water vapor channels. Synoptic scale
ascent remains weak through Saturday, however a mid/upper shortwave
now located in far southeast Montana into far northwest will rotate
around the upper low and into the southern James River Valley
Saturday afternoon. Mixed Layer Cape 300 to 500 J/kg with could
lead to an isolated thunderstorm in Dickey County Saturday afternoon.
Effective 0-6km Bulk Shear remains weak at 20kt. The gridded forecast
blend has this handled well. Otherwise expect a sunny sky Saturday
with highs mostly in the 80s, to lower 90s far west.

.LONG TERM...(Saturday night through Friday)
Issued at 246 PM CDT Fri Sep 8 2017

The upper low exits the southern James River Valley Saturday
evening, with more or less a zonal flow setting up across
western/central ND Sunday through Tuesday. A transition to
southwest flow aloft then commences Wednesday through Friday as
an upper low shifts into the northwest and Northern Rockies.

With the zonal flow Sunday, a cold front moves from west to east
during the day. Moisture appears lacking until the front crosses
near or east James River Valley late Sunday afternoon/evening.
Instability is present along and ahead of the front, but forcing
for ascent lags behind, located across northern ND into Saskatchewan
and Manitoba through 00z Monday. Ascent does catch up Sunday
evening, but the main portion of instability by that time slides
off to our east. The gridded forecast is dry and will keep it that
way for now. Dry and warm Monday through Tuesday, then a gradual
increase for shower/thunderstorms Wednesday through Friday. The
latest operational GFS is trending towards the more unsettled
and consistent ECMWF. Temperatures cooling into the 70s by Friday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 929 PM CDT Fri Sep 8 2017

VFR conditions are expected this evening at TAF sites. Late
tonight, patchy fog is possible over central North Dakota. Did
continue the mention of patchy fog at Bismarck and Minot as per
the previous shift. However, latest runs of mesoscale models have
backed off a bit on the extent of low stratus/fog. Think there
will be some patchy fog around, but not extensive enough to go
more than a scattered layer and VCFG at KBIS and KMOT. We also
added a LLWS at KDIK and KISN after midnight as low level jet
increases over this area.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...TWH
SHORT TERM...KS
LONG TERM...KS
AVIATION...TWH




Area Forecast Discussion

National Weather Service Cheyenne WY

 530 PM MDT Fri Sep 8 2017

.SHORT TERM...(This evening through Sunday night)
Issued at 320 PM MDT Fri Sep 8 2017

Radar returns show scattered showers and a few thunderstorms over
the Snowy and Sierra Madre Mountains and nearby valleys, moving to
the east. SPC mesoanalysis depicts a marginally unstable environment
across the plains with 500-1000 J/kg of SBCAPE analyzed along
with weak inhibition. Therefore, won`t make any changes to the
forecast from the earlier update as we continue to expect showers
and storms to continue east across the plains in this environment.

For tonight, convection will come to an end by midnight. Smoke is
still an issue today over much of the area, but latest HRRR
guidance shows the smoke column pushing to the east with the upper
level trough by Saturday morning. Hopefully that will be the last
of the smoke issues for a little while at least. Saturday will
see warmer temps back into the 80s and 90s as the thermal ridge
moves overhead. We`ll remain within the plume of mid/upper level
moisture, so expect a few afternoon showers/storms mainly along
and west of the Laramie Range in the afternoon as the eastern
plains look to reside within an area of subsidence in the wake of
the upper trough.

A sfc trough will slide south across the plains early on Sunday
while a weak vort max treks east across WY in the afternoon. The
sfc trough will lay up against the Laramie Range through the
afternoon providing enhanced convergence for convective
development. Adequate moisture is expected to still be in place,
therefore should see another round of showers and storms develop
in the afternoon and evening mainly along and west of the Laramie
Range.

.LONG TERM...(Monday through Friday)
Issued at 320 PM MDT Fri Sep 8 2017

Above normal temperatures expected to hold over the CWA next week
as the area will be generally under the influence of upper
ridging. The upper ridge will initially be situated over the
intermountain region early in the week before slipping eastward
into the plains by late week. Isolated afternoon and evening
convection will be possible in the Monday through Weds period
mainly over the mtns. A little better chance for convection may
arrive Thursday as an upper trough begins to approach from the
northwest.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday afternoon)
Issued at 530 PM MDT Fri Sep 8 2017

VFR. Scattered showers and a few weak thunderstorms will primarily
affect southeast WY terminals through mid-evening. Winds will be
light, except variable and gusty with the passing showers.

&&

.FIRE WEATHER...
Issued at 320 PM MDT Fri Sep 8 2017

Humidity values this afternoon are around 20 percent or higher
over most of the district, with lower readings across Carbon
County. Winds have been a bit breezy today with gusts of 15 to 25
mph. Showers and thunderstorms have developed west of the Laramie
Range this afternoon and expect this activity to shift over the
plains through the evening. The dry low levels may limit rainfall
to around one tenth of an inch, and gusty downdraft winds are a
very good possibility. We are still looking at continued chances
for thunderstorms through the weekend but mainly in the mountains.
Further east, mostly dry and very warm conditions will continue
as the upper level ridge remains overhead.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

$$

SHORT TERM...RJM
LONG TERM...RE
AVIATION...MAJ
FIRE WEATHER...RJM




Area Forecast Discussion

National Weather Service Green Bay WI

 1042 PM CDT Fri Sep 8 2017

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Saturday
Issued at 225 PM CDT Fri Sep 8 2017

The latest RAP analysis and satellite/radar imagery show high
pressure centered just north of Lake Superior early this afternoon.
Scattered to broken cu developed by late morning over eastern WI
with help from winds off Lake Superior and Michigan.  With plenty of
clear skies upstream, concerns tonight revolve around the potential
for frost.

Tonight...Rather large high pressure system will be sliding into the
central Great Lakes, providing mostly clear skies and light winds.
Could see a few strands of strato-cu move into east-central WI late
as winds turn to the east off Lake Michigan.  Otherwise, main focus
is on temps tonight.  With similar pwats to last night, low temps
should be around last nights readings, perhaps slightly cooler over
eastern WI where there will be less clouds.  So will issue a frost
advisory for the same areas as last night, and expand it to include
northern Oconto and northern Marinette counties.  Should also see
patchy ground fog over northern WI as well. Lows ranging from the
lower 30s in the north to the mid 40s near Lake Michigan.

Saturday...High pressure will remain over the region.  Should see
some cu develop by mid-morning over eastern WI. Southeast winds will
then push the cu to the west of the Fox Valley and Bay in the
afternoon.  Temps will be a degree or two warmer than todays highs.

.LONG TERM...Saturday Night Through Friday
Issued at 225 PM CDT Fri Sep 8 2017

Not much change in the long term since the previous forecast.
Overall, quiet weather is expected.

Surface high pressure will be east of Wisconsin on Sunday with a
broad mid-level ridge stretching from the southwest CONUS to the
western Great Lakes. This setup will be the general trend for the
majority of the forecast period. Weak mid-level energy and some
associated pcpn tries to moves in from the northwest towards the
end of the weekend and early in the week, but models have been in
agreement that this weakens before reaching the forecast area,
with surface high pressure also keeping Wisconsin dry.

Temperatures in far northeast Wisconsin may briefly fall into the
upper 30s early Sunday morning. Beyond Sunday morning
temperatures will be on the upswing with no frost potential
currently in sight. Temperatures bounce around or slightly above
normal from Sunday afternoon through the upcoming week.
&&

.AVIATION...for 06Z TAF Issuance
Issued at 1040 PM CDT Fri Sep 8 2017

With mostly clear skies and light winds in place, patchy ground
fog will develop in parts of northern WI overnight, but
confidence is not high enough to include at the RHI TAF site.
Southeast winds may bring scattered lake-enhanced clouds off Lake
Michigan overnight into Saturday morning, and these may affect
MTW, GRB and ATW. Otherwise FEW to SCT cumulus clouds will develop
with the heating of the day.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 8 AM CDT Saturday for WIZ005-010>013-018-
019-021.
&&

$$

SHORT TERM.....MPC
LONG TERM......KLB
AVIATION.......Kieckbusch



Area Forecast Discussion

National Weather Service Lincoln IL

 928 PM CDT Fri Sep 8 2017

.UPDATE...
Issued at 928 PM CDT Fri Sep 8 2017

1028mb high centered over the Great Lakes is dominating the
weather across central Illinois tonight...providing clear and cool
conditions. Winds were light/variable earlier in the evening:
however, a wind shift line has dropped southward into the area...
with 02z/9pm obs showing increasing E/NE winds along the I-74
corridor. As this feature continues to shift southward, 6-12mph
winds will spread across much of the KILX CWA as the night
progresses. The wind will help keep the boundary layer mixed and
will prevent overnight lows from dropping quite as low as they
have in recent nights. Made some adjustments to hourly temps, but
maintained previously forecast lows in the lower 50s.

&&

.SHORT TERM...(This evening through Saturday)
ISSUED AT 300 PM CDT Fri Sep 8 2017

High pressure with clear skies and low surface dewpoints will set
the stage for cooler than normal lows again tonight, although not
quite as chilly as the past two nights. A weak surface
trough/gust front is still depicted in the HRRR to push into
central Illinois from the NE this evening, with some gusty E-NE
winds for a few hours. Those winds will work to keeps lows warmer
than last night, as lows bottom out in the lower 50s instead of
40s.

Sunny skies are expected to start the day on Saturday, but cu-
rule outlooks are pointing toward a cumulus field developing from
late morning to mid afternoon across at least the northeast half
of our forecast area. The moisture will be shallow, and in the
lower levels, so cloud cover should dissipate by sunset. Highs on
Saturday are expected to be a degree or two cooler than today,
with mid 70s near Danville in the northeast and lower 80s around
Jacksonville in our southwest area.

.LONG TERM...(Saturday night through Friday)
ISSUED AT 300 PM CDT Fri Sep 8 2017

Primarily dry weather is expected over the next week, under the
influence of high pressure centered in the Great Lakes and a
relatively dry airmass. The dry air will allow for fairly large
diurnal temperature swings, with lows in the upper 40s to mid 50s
and highs in the mid 70s to low 80s. The coolest days and nights
look to be Saturday night through Sunday night, with the coldest
850mb air of the next week resides across Illinois.

The primary concern for the extended remains the remnants of Irma,
and how close to Illinois the surface low will reach from the
southeast states.

Model guidance continues to show the remnants of Irma moving
north into the Ohio Valley by late Tuesday/early Wednesday, but
stalling in western Tennessee before either dissipating or
departing back to the east, due to a blocking pattern and
building heights mid-week. The ECMWF and Canadian GEM both push
showers from Irma into our far SE counties, mainly S of I-70,
while the GFS stalls Irma in central Tennessee with no rainfall in
our forecast area.

The trends in the 12z guidance has been to slow down the progress
of Irma into and out of Tennessee next week, keeping slight chance
PoPs in our SE counties from Tuesday morning through Wednesday
afternoon. Any showers that do reach our area will be light, with
no thunder expected, as the system occludes and dissipates.

A general warming trend is expected from Wed to Friday once Irma
departs, as rising heights progress into Illinois from the
Plains. 850mb temps look to climb into the upper teens by Friday,
supporting highs into the mid 80s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 637 PM CDT Fri Sep 8 2017

VFR conditions will prevail through the entire 00z TAF period.
Latest obs show clear skies and light E/SE winds early this
evening: however, a wind shift line noted from KVYS to just south
of KIKK is advancing southward and will impact the central
Illinois terminals over the next couple of hours. HRRR has been
consistently showing this feature arriving at the I-74 sites at
about 02z...resulting in a wind shift to the NE and gusts of
14-18kt. Have timed the wind shift to KDEC by 03z and to KSPI by
04z. Winds will once again become SE at less than 10kt by Saturday
morning.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...Shimon
LONG TERM...Shimon
AVIATION...Barnes



Area Forecast Discussion

National Weather Service Marquette MI

 723 PM EDT Fri Sep 8 2017

.SHORT TERM...(This evening through Saturday)
Issued at 347 PM EDT FRI SEP 8 2017

Water vapor imagery and RAP analysis still show an amplified pattern
across N America, though amplitude has decreased over the last
24hrs. Ridge extends from NM thru MT and into Saskatchewan/Manitoba
while downstream trof extends from Quebec into the eastern CONUS.
The mid-level trof has been shifting e, and now that the associated
upper jet axis on the backside of the trof is e of the fcst area,
weather conditions have improved after the unsettled weather of the
last few days. Although the day started clear for much of the fcst
area, except over portions of n central Upper MI, 850mb thermal trof
over the Upper Lakes combined with moisture added by Lake Superior
led to blossoming of stratocu during the mid and late morning as
daytime heating got underway. These clouds are now beginning to mix
out/dissipate. It`s still cool with temps currently only in the
upper 50s/lower 60s.

Quiet weather will dominate the short term as upstream mid-level
ridge shifts to the Upper Mississippi Valley/western Great Lakes.
Main concerns are min temps and frost coverage tonight. With sfc
high pres drifting across the area tonight, resulting in light/calm
wind, stage will be set for a chilly night. At 0.35 to 0.45 inches
or roughly 50pct of normal, precipitable water tonight will be
similar to or just a little lower than last night, enhancing
radiational cooling. With a drier boundary layer than last evening,
tonight will start off with a quicker temp fall than last night.
Overall, have generally utilized the lower end of avbl guidance for
min temps. Frost should become widespread across much of the fcst
area, and frost advy will be issued for all counties except Keweenaw
County. Developing light return flow on backside of sfc high pres
will limit frost in the downslope areas of far western Upper MI.

A nice Sat is shaping up under abundant sunshine. Only potential
concern, and minor at that, is se winds off Lake MI may contribute
to sct stratocu developing for a time during the morning/early aftn
over the s central fcst area. Temps will top out in the 60s across
the board. May reach 70F in a few spots over the w.

.LONG TERM...(Saturday night through Friday)
Issued at 227 PM EDT FRI SEP 8 2017

A rather quiet stretch of weather is expected well into next week
across the Upper Great Lakes by mid-September standards. Most, if
not all, of the CWA will remain dry through at least next Wednesday
per 12Z model guidance. The only very small chance of rain will
be Monday evening as Upper MI is brushed by a mid-level trough to
the north. With marginal forcing and fairly dry low-levels, will
continue to keep the forecast dry at this time.

Patchy frost is expected across the interior east half Saturday
night as high pressure departs to the east. Light southerly flow
should offset some cooling across the west half, but patchy frost
will still be possible for the typically coldest locations.
&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 722 PM EDT FRI SEP 8 2017

Under high pressure and continue dry air mass, VFR conditions will
prevail at KIWD/KCMX/KSAW through this forecast period.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 347 PM EDT FRI SEP 8 2017

Lack of any significant weather systems in the vcnty of the Upper
Lakes will keep winds mostly blo 20kt thru the middle of next week.
During the period, stronger winds will occur in the Sat night thru
Mon time frame under tighter pres gradient btwn high pres to the se
and a weak sfc trof that will sweep across northern Ontario.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Frost Advisory from midnight EDT /11 PM CDT/ tonight to 9 AM EDT
     /8 AM CDT/ Saturday for MIZ002>007-009>014-084-085.

Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...Rolfson
LONG TERM...Kluber
AVIATION...KEC
MARINE...Rolfson



Area Forecast Discussion

National Weather Service Pocatello ID

 244 PM MDT Fri Sep 8 2017

.DISCUSSION...
Our two main forecast concerns today through Saturday are smoke and
thunderstorms. With increasing moisture on a S/SW flow, we expect
isolated to widely scattered showers/t-storms this afternoon/eve,
with a repeat performance Sat. Lift today will largely be
provided by terrain, so greatest chance will be over the Central
Mntns and mntns east of I-15, but isolated storms cannot be ruled
out almost anywhere as t-storm outflow boundaries serve as lift
where terrain is lacking. Lift Sat may be aided a bit by a weak
trough pushing through, resulting in slightly more activity.
Strongest storms both days could include gusty winds/small hail,
although the severe weather threat is very low. With less smoke
and based on trends so far, have raised high temps several degrees
this afternoon, likely to reach/slightly exceed yesterday`s
values.

Forecast confidence remains high in weak high pressure Sun-Mon,
providing dry weather. Models are now showing perhaps a shower/t-
storm Tues afternoon/eve in the Central Mntns or Southern Highlands,
so have added a 15-20% chance to these areas.

Long range guidance slowly coming into better agreement Wed-Fri on
the evolution of our next low pressure system. The
NAM/GFS/Canadian all now maintain a closed low into central CA or
central NV by Wed AM, then open the low into a trough/front that
pushes E through the region Wed eve or Thurs morning. Another
wave/front looks to follow Thurs night or Fri AM. However, due to
differences in the models over timing and precip coverage/amounts,
forecast confidence in the details remains relatively low.
Confidence is increasing that this system will bring a solid
chance of showers/t-storms region-wide. Have nudged up precip
chances Wed and Thurs for the entire area, generally 25-45%,
highest in the mntns. Expect additional adjustments in the coming
days. - KSmith/Valle

&&

.AVIATION...
Moisture continues to stream northward today across eastern
Idaho. So far, things have been slow to develop as cloud cover and
lingering smoke is keeping instability down. The most likely
areas for any showers and storms will be over the mountains,
although just about any location COULD see storms thorugh Saturday
especially in association with outflow boundaries. We have VCTS
and VCSH for all TAF sites at some time or another. If we can get
some decent storms going, outflow winds over 30mph are possible.
We should see smoke gradually thinning out, however KSUN may be
more stubborn to see it dissipate due to closer proximity to
fires. VFR weather is forecast overall although dips into MVFR or
IFR are not out of the question due to smoke or storms moving over
an airport. - Keyes

&&

.FIRE WEATHER...
Monsoon moisture will continue to stream over the state for the
next 24 hours or so. Whether we see more coverage than
isolated/widely scattered is debatable. It depends on cloud cover
which can be tough to figure out more than a few hours in advance.
For now, we will forgo any watches or warnings, but we could
easily reverse course based on real-time trends. Gusty winds over
30mph are possible with little rainfall with stronger cells that
form. On Saturday, the overall wind pattern increases across the
central mountains and Upper Snake Highlands as a storm swings east
along and north of the US/Canada border. Gusts 25-35mph are
possible even outside of storms. Humidity values will come up
quite a bit but a fire could spread with those winds in the right
circumstances. We go back to dry conditions and high pressure
starting Sunday, continuing until the middle and end of next week.
A storm coming into the Pacific Northwest will draw up moisture
from the southwest, increasing the chance of showers and storms
once again. - Keyes

&&

.AIR STAGNATION...
As forecast, most of SE ID is seeing slowly improving visibilities
and air quality as southerly winds have started to clear out some
of our pesky smoke! Advisories from Idaho DEQ have been lifted for
some but continue for others...continue to refer to our Air
Quality Alert (AQA) products for details. Latest monitoring from
Idaho DEQ shows values have risen into the Moderate category
across most of the forecast area. The chance of storms (both their
associated moisture and outflow winds) over the next 2 days may
further help clear out the smoke. The HRRR Smoke Model and
AIRPACT-5 guidance from Washington State University both exhibit
good agreement on an improving trend in the smoke this afternoon
through Sat, especially across the Snake Plain. The Central Mntns
have the best chance of holding on to more smoke for the next
several days, although slight improvement is likely here too. With
good model agreement and observational trends matching our
expectations, our forecast confidence is moderate to high in this
scenario. With that said, however, we have not removed a mention
of areas of smoke from the forecast for Sun-Fri. Dozens of large,
active wildfires continue across the NW, and both the NAM/GFS
suggest winds in the mid-levels of the atmosphere will turn into
the W Sun and NW Sun night, which MAY push more smoke back into
portions of our region, especially the Central Mntns. The last few
frames of AIRPACT-5 suggest this trend. Don`t let your guard down
yet. - KSmith/Valle

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$




Area Forecast Discussion

National Weather Service Pueblo CO

 304 PM MDT Fri Sep 8 2017

.SHORT TERM...(This evening through Saturday)
Issued at 303 PM MDT Fri Sep 8 2017

The upper ridge axis continues to shift eastward allowing a better
fetch of moisture into southern CO.  A weak disturbance embedded
within the flow has triggered scattered thunderstorms across the
mountains early this afternoon.  High res models continue these into
the evening before most dissipate overnight.  However the moisture
plume may stay active with showers through the overnight hours
across the western mountains so have hung onto some isolated pops
out that way.  Main threats with thunderstorms will be locally gusty
winds up to 40 mph...lightning...and moderate to heavy rainfall.

Flow aloft shifts more westerly on Saturday which should help clear
out some of the smoke across southern CO.  Latest HRRR Vertically
Integrated Smoke product shows some pretty good clearing tomorrow
so will not extend smoke in the grids beyond tonight.  Otherwise...a
fairly similar pattern is expected tomorrow with another round of
thunderstorms over the mountains during the afternoon with brief
moderate to heavy rain...gusty winds and lightning the primary storm
threats. -KT

.LONG TERM...(Saturday night through Friday)
Issued at 303 PM MDT Fri Sep 8 2017

Sat night through Tue, an upper ridge will be over the forecast area
with enough moisture over the area for daily pcpn chances, mostly
over and near the higher terrain.  High temps generally look like
they will be around to slightly above average.

Wed and into Thu, a couple disturbances are forecast to move acrs
the area, with another one on Fri.  These will potentially bring a
better chance for pcpn to the southeast plains, in addtion to the
higher terrrain locations. High temps these days are expected to be
a little above average.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 303 PM MDT Fri Sep 8 2017

Thunderstorms developing over and near the mountains may affect KALS
and KCOS this afternoon so will carry VCTS or tempo -TSRA until 02z.
Thunderstorms are expected to remain too far west of KPUB to be of
much affect. Erratic wind gusts up to 40 kts and brief VFR Cigs and
VIS will be possible with thunderstorms through this evening. Most
will diminish by 02z but a few showers and thunderstorms may linger
over the mountains into the early morning. On Saturday a repeat
performance of afternoon showers and thunderstorms over and near the
mountains can be expected.  With more of a westerly component to
winds aloft, the smoke is expected to clear out some across eastern
CO which should help improve visibilities. -KT

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...KT
LONG TERM...28
AVIATION...KT




Area Forecast Discussion

National Weather Service Sacramento CA

 255 PM PDT Fri Sep 8 2017

.SYNOPSIS...
Warming trend with a threat of afternoon showers and thunderstorms
over portions of the mountains through early next week. More
widespread showers and thunderstorms possible middle of next week.

&&

.DISCUSSION...
Mid level southerly flow ahead of 576 DM upper low centered about
100 NM west of KMRY this afternoon is leading to some isolated
thunderstorm development over our mountains. Mosaic 88-D showing
a few storms over the Coastal Range and also higher terrain of the
Sierra Nevada. Latest HRRR suggesting activity ending by around
04z Sat. Afternoon temps running upwards of 11 degrees warmer than
24 hours ago and should max out near seasonal normal for early
September.

Upper low forecast to remain offshore and drift slowly south to
about latitude 32N Sunday then gradually meander back northward
early next week. Interior NorCal will warm over the weekend as the
low drifts farther away. Highs Sunday/Monday will be in the upper
90s in the Central Valley with triple digit heat in the Northern
Sacramento Valley. Main threat of afternoon showers or thunderstorms
will be over the Sierra Nevada, mainly south of I-80 Sat/Sun.
Threat spreads farther north Monday to include Coastal Range and
mountains of W Plumas and Shasta as the low moves approaches
again.

PCH

&&

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)
Forecast remains on track as model output indicates an upper low
tracking inland Tuesday into Wednesday. As a result, widespread
showers and thunderstorms are expected given enough instability
and moisture. Best chance of this convection will be over the
mountains, but the dynamics of this system would suggest potential
for low elevation thunderstorms as well. Drier weather is
projected toward the end of next week. Daytime highs will remain
near or a few degrees below seasonal averages.

&&


.AVIATION...
Scattered thunderstorms continuing across NorCal mountains
through 04z Saturday, then thunderstorms mainly south of Tahoe
Saturday between 18z Saturday and 03z Sunday. Otherwise, VFR
conditions expected across interior NorCal. Winds will remain
generally below 10 kt across Valley TAF sites, with local gusts to
20 kt near the Delta.


&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$