Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/02/20

Area Forecast Discussion

National Weather Service La Crosse WI

 1049 PM CDT Thu Oct 1 2020

.SHORT TERM...(Tonight through Friday)
ISSUED AT 144 pm CDT Thu Oct 1 2020

Currently, water vapor imagery showing a fairly vigorous PV-anomaly
rotating southeastward across our area/Great Lakes region. Radar
showing quite a bit of shower activity across our area with this
feature and very cold cyclonic flow/steep low level lapse rates
overhead. Visible satellite also showing expansive amount of
cumulus/stratocumulus extending across WI/MN/southern Canada.
Temperatures as of 1 PM were unseasonably chilly with readings in the
40s/50s.

Look for this mid-level wave and surface cold front to push
southeast of the area by this evening but clouds could be stubborn
to clear as high pressure builds in. RAP model does show a slow
decrease in 925mb RH however and forecast soundings show this as
well. With 925mb temperatures falling to near 0C, look for good
radiational cooling where breaks occur in the cloud. As such, will
keep Frost Advisory going as is (1 am to 8 am Friday) with lows
expected to fall into the upper 20s (central WI), to the lower/mid
30s elsewhere.

High pressure drifts across the area Friday with partly to mostly
sunny skies expected. Despite sunshine, temperatures will remain
chilly with highs only in the mid 40s to lower 50s.


.LONG TERM...(Friday night through Thursday)
ISSUED AT 144 PM CDT Thu Oct 1 2020

Northwest flow continues through the weekend with another fairly
strong PV anomaly dropping southeast into the area Saturday/Saturday
night. Strongest part of this energy.surface low appears to be south
of the forecast area per latest NAM/GFS but plenty of cool cyclonic
flow aloft over us, so expecting scattered showers as a result.
Otherwise, continued colder than normal with highs only in the
40s/lower 50s.

High pressure builds back in for Sunday for dry but continued chilly
conditions. Plan on highs again in the 40s/lower 50s.

Warm air advection kicks in Monday on breezy south winds on the
backside of the departing high and in advance of a cold front
dropping through the Northern Plains. Look for highs Monday in the
mid 50s to lower 60s.

Latest GFS/ECMWF in good agreement bringing another trough/surface
cold front through Monday night into Tuesday. This front looks to
come through mostly dry though. Otherwise, plan on highs in the 60s.

One last trough/surface low in northwest flow aloft looks to impact
the area Tuesday night into Wednesday with squattered showers but
then drying/warming taking place Thursday as mid-level ridging
amplifies over the central CONUS.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1049 PM CDT Thu Oct 1 2020

VFR conditions are expected through the period. The large area of
high pressure over the eastern Dakotas into Kansas will drift east
across the area through Friday evening and keep the winds light
out of the northwest. The flow aloft will remain north/northwest
which will continue to bring in some scattered to broken clouds
from time to time for occasional VFR ceilings.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Frost Advisory until 8 AM CDT Friday for WIZ029-032>034-041>044-
     053>055-061.

MN...Frost Advisory until 8 AM CDT Friday for MNZ079-086>088-094>096.

IA...Frost Advisory until 8 AM CDT Friday for IAZ008>011-018-019-029-
     030.

&&

$$

SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04



Area Forecast Discussion

National Weather Service Boise ID

 814 PM MDT Thu Oct 1 2020

.DISCUSSION...Upper level ridge will continue above normal
temperatures, light winds and dry conditions though Friday.
Satellite showed smoke across the area though the smoke remains
aloft except near local fires. Could see smoke from fires in the
West Central mountains on Friday as the flow becomes more
northerly. Otherwise, temperatures on Friday will reach about 10
degrees above normal. No update needed at this time.

&&

.AVIATION...VFR. Smoke layers aloft. Patchy valley fog in the
mountains overnight. Surface winds: 10 kts or less overnight,
increasing to NW 5-15 kts Friday afternoon with the strongest winds
to the SE of KBOI. Winds aloft near 10k ft MSL: NW 5-15 kts.

Weekend outlook...Mostly clear with smoke layers. Patchy mountain
valley fog during the mornings. Breezy conditions over higher
terrain on Sunday afternoon.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Saturday night...Persistent upper
ridge through Saturday night, then flattening Sunday as a weak
short wave trough and surface cold front come through. The front
will have little effect on surface temps but cooling aloft will
cause slight destabilization and increased mixing. The mixing will
allow smoke layers aloft to get into the lower levels. HRRR smoke
model increases surface smoke in Baker County/OR and western
Idaho beginning late Friday, but Harney and Malheur Counties will
have less smoke. Models develop breezy northwest winds in the
Snake Basin Friday afternoon, otherwise light winds through
Saturday night.

LONG TERM...Sunday through Thursday...The upper level ridge
will weaken as a weak cold front tracks across MT on Monday with
slightly cooler temperatures, but still around 5-10 degrees above
normal. The upper level ridge will rebuild over the region by
Tuesday with warm and dry conditions through Thursday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.

&&

$$

www.weather.gov/Boise
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise

DISCUSSION...JDS
AVIATION.....AL
PREV SHORT TERM...LC
PREV LONG TERM....KA



Area Forecast Discussion

National Weather Service Denver/Boulder CO

 803 PM MDT Thu Oct 1 2020

.UPDATE...
Issued at 759 PM MDT Thu Oct 1 2020

Little change needed to previous fcst. Smoke, mainly
from the Mullen fire, will continue to affect the area thru
Friday.

&&

.SHORT TERM...(This evening through Friday)
Issued at 1230 PM MDT Thu Oct 1 2020

The high amplitude ridge continues to be over the western portion
of the CONUS with northwest upper level flow over the region.
Temperatures were slightly cooler today behind a cooler flow of
easterly winds on the surface in the post-frontal airmass. Dry
conditions will continue through Friday with a gradual increase in
temperatures as 700 mb temps approach +8-9.5C but still hovering
around seasonal normals. The bigger impacts will continue to be
the smoke produced by the Cameron Peak and Mullen fires in Larimer
county and just across the border in Wyoming. Current wind
patterns and HRRR smoke models show another day of extensive smoke
cover over the northern and central foothills as well as the lower
elevations of I-76 and south. A mixture of near-surface and
elevated smoke could hinder some increase in temperatures tomorrow
afternoon as well as provide hazardous air quality conditions for
sensitive groups.

.LONG TERM...(Friday night through Thursday)
Issued at 1230 PM MDT Thu Oct 1 2020

No significant changes to the long term. Main theme is continued
dry conditions with above normal temperatures and persistent
elevated fire danger. Areas of smoke will continue to be an issue
at times in the mountains, foothills and adjacent plains. On the
synoptic scale, a ridge of high pressure will remain over the west
coast, with a northwesterly flow over CO. A short wave trough is
expected to pass to drop into the Midwest Friday night into
Saturday morning. There is the potential of an isolated shower
over the far northeast plains Friday evening as a weak cold front
pushes across the area, but that is basically it. Temperatures on
Saturday will drop back into the mid/upper 60s. By Sunday
however, temperatures will climb back into the 70s. The flow aloft
will weaken on Sunday, as the flow aloft transitions to
west/northwesterly component. On Monday, the wind will increase
over the region and warms up as a weak lee trough over eastern CO
generates an additional downslope component along the Front
Range. A weak front then pushes across the region late
Monday/Monday night but no real impact from this feature aside
from a brief period of gusty winds. Tuesday through Thursday, the
ridge will spread over the central Rockies. Temperatures will
remain above normal with generally lighter winds under the ridge
axis.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 759 PM MDT Thu Oct 1 2020

Winds have become light southeast and should go to drainage
by midnight. Latest HRRR Smoke indicates some restriction
in visibility late tonight through Friday.

&&

.FIRE WEATHER...
Issued at 1230 PM MDT Thu Oct 1 2020

There will be elevated fire danger through the middle of next
week with continued dry and warm conditions. The biggest potential
for red flag conditions will be Monday with stronger winds and
very low humidities over mountains, mountain valleys and elevated
terrain. Otherwise, the wind will be light which will help
slightly offset the persistently dry conditions. Areas of smoke
will continue to impact the mountains, foothills and adjacent
plains as well.

&&

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

$$

UPDATE...RPK
SHORT TERM...Bowen
LONG TERM...Cooper
AVIATION...RPK
FIRE WEATHER...Cooper



Area Forecast Discussion...UPDATED

National Weather Service Chicago/Romeoville, IL

 951 PM CDT Thu Oct 1 2020

.UPDATE...
950 PM CDT

Some mainly tweaks to the forecast for the remainder of tonight
into Friday morning. The Frost Advisory continues for far northern
Illinois.

The diurnally driven showers have faded with most of the showers
on the radar scope now being lake effect driven into far northwest
Indiana and far southwest Michigan. These should see a gradual
intensification due to deepening cloud layers/increasing cold
advection over the warmer lake waters, as well as a better
propensity to see isolated lightning. RAP soundings from the
Indiana nearshore modified for an average of southern Lake
Michigan temperatures in the mid 50s provide lake induced CAPE
values of 600-1,000 J/kg. This is down some from earlier RAP/NAM
forecasts but still sufficient for moderate showers. Also have
noted the updrafts have struggled to remain rooted on the low-
level convergent axis across southern Lake Michigan. This may be
owing to still stout 850-925 mb wind flow (25-30 kt on KLOT VWP).
Most CAMs focus the boundary into the northwest Indiana shore
into the overnight and increase the coverage of showers as the
now developing mesolow moves into far northwest Indiana. Still a
chance far northeast Illinois including the Chicago lakefront gets
clipped with this shower activity including around daybreak. The
potential for a few waterspouts, including possibly near or into
the nearshore, remains for overnight.

Otherwise over land, a fairly large cloud area is present across
southern Wisconsin into northeast Iowa, associated with a slight
enhancement of cold advection around 850 mb. This has kept
temperatures and dew points in the mid 40s underneath. These
clouds are not locked under a strong inversion or basically any
inversion at all using the 00Z GRB sounding as a proxy. That means
these could gradually dissipate, but at this time it looks like
at least several hours where far northern Illinois should struggle
to fall much for temperatures into the early overnight thanks to
mostly cloudy conditions. Have nudged up mins a tad but continue
with the frost mention and the Advisory, as the back edge of these
clouds is expected to move over the area a few hours before
daybreak.

MTF

&&

.SHORT TERM...
304 PM CDT

Through Friday night...

Scattered showers will gradually taper over much of the CWA this
evening as the attendant shortwave departs. Portions of northwest
Indiana will be the exception to this with a lake effect shower
event expected to develop this evening into the overnight hours as
a favorable northerly fetch develops over southern Lake Michigan.
Surface-850 mb temperature differentials of 16-18 degrees
Celsius, CAPE values of around 1500 J/kg, and ELs upwards of 30000
ft will be more than enough to support a convective band of lake
effect showers that could produce localized rainfall totals
approaching 1 inch if sufficient training materializes. Low
freezing levels will also support lightning and some small
hail/graupel, both of which were already observed within some
shower cells that moved across northwest Indiana earlier today.
Conditions also remain favorable for the development of
waterspouts over southern Lake Michigan tonight, so that will be
something to keep an eye on as we head into this evening.

Regarding temperatures tonight and the potential for frost: have
elected to not make any alterations to the inherited Frost Advisory.
While some thinning of the diurnally-enhanced cloud cover will
likely take place this evening, additional patches of lower cloud
cover appear possible as our region remains on the cyclonic shear
side of the upper jet. Forecast soundings indicate some degree of re-
saturation taking place as well later this evening as another
upstream vort max translates overhead. Given this and the potential
for winds to remain ever-so-slightly elevated tonight, the signal
for widespread frost doesn`t appear high enough to warrant an areal
expansion at this point, but will let the evening shift take an
additional look.

The lake effect showers will likely continue into Friday morning
before diminishing as height rises and associated subsidence
slash ELs significantly while a northwesterly wind shift across
the entirety of southern Lake Michigan simultaneously reduces
surface convergence. Dry weather is then expected the rest of the
day as a region of surface high pressure builds in.

High temperatures tomorrow should be a smidge cooler than today as
the core of a rather cool airmass more fully overspreads the region.
For tomorrow night/Saturday morning, the floor on overnight
temperatures is certainly lower than it is tonight as the core of
the surface high slides overhead and winds go light and
variable/calm during the evening. The main questions are how
expansive the lingering stratocumulus remains from Friday, and how
quickly another round of cloud cover returns ahead of the next
incoming system. Should things clear out and remain that way, could
envision some locations flirting with the freezing mark.
That said, latest indications point to cloud covering continuing to
play a role here and may end up holding temperatures up a bit.
The offered blended guidance still appears to be a reasonable
estimate of things at this time, but we`ll continue to re-evaluate
as additional guidance becomes available.

Ogorek/Carlaw

&&

.LONG TERM...
237 PM CDT

Saturday through Thursday...

Unseasonably cool conditions will continue through the weekend,
but warmer temperatures are expected for the early to middle part
of next week. The only notable chance of rain for the area during
the period looks to be late Saturday afternoon and night. During
this period, our next upper level impulse will approach the area
from the northwest and push another cold front southward across
the area by early Sunday morning. While the rain may linger across
eastern sections of the area Sunday due to the possibility for
more lake effect showers, it appears most areas across IL will
begin to dry out by the afternoon. However, breezy northerly winds
will make for a chilly afternoon as temperatures remain in the
low to mid 50s.

Surface high pressure looks to set up over the area Sunday night
into early Monday morning. Light winds and clearing skies with
this high could once again result in frost potential with lows in
the low to mid 30s inland from the lake Sunday night.

This surface high is expected to shift to our southeast on Monday,
which will in turn allow the winds to shift southerly for Monday
and Tuesday. This will help push temperatures back into the 60s
for Monday and Tuesday. Another storm system may then impact parts
of the Great lakes around Midweek. At this time it appears the
primary precipitation threat from this system may remain to our
north. However, an associated cold front looks to shift southward
over the area by midweek. While this could bring a period of
cooler temperatures later in the week, it looks as though it could
be short lived, with a return to warm conditions beyond the
current forecast period.

KJB

&&

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

623 PM...Forecast concerns include...

Scattered showers this evening.
Lake effect rain showers tonight in northwest IN.
Lake breeze/northeast wind shift late Friday afternoon.

Scattered showers will slowly dissipate through mid evening with
lake effect rain showers continuing into the overnight hours in
northwest IN and at gyy. The stronger showers may produce brief
gusty winds. Once this activity ends tonight...dry weather is
expected Friday.

Prevailing winds are expected to remain northwest through Friday
afternoon and then will shift to the northeast late Friday
afternoon or early Friday evening for the Chicago terminals.

Prevailing cigs are expected to remain vfr through the period...
possibly scattering out Friday afternoon. Brief mvfr cigs will be
possible with the rain showers and mvfr cigs are likely over the
lake tonight and some of these mvfr cigs will be possible near the
Lake Michigan shore...especially toward gyy. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Frost Advisory...ILZ003-ILZ004-ILZ005...3 AM Friday to 9 AM
     Friday.

IN...None.
LM...Small Craft Advisory...Winthrop Harbor to Burns Harbor until
     1 PM Friday.

     Small Craft Advisory...Burns Harbor to Michigan City IN until 4 PM Friday.

&&

$$

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Area Forecast Discussion

National Weather Service Marquette MI

 746 PM EDT Thu Oct 1 2020

.SHORT TERM...(This evening through Friday)
Issued at 409 PM EDT THU OCT 1 2020

WV imagery and RAP analysis indicated an amplified pattern with a
ridge over western North America and a trough from northern Quebec
to the southern Mississippi Valley resulting northwest flow through
the western Great Lakes. At the surface, northerly flow prevailed
between a ridge through the Plains and a trough from southern
Ontario into northern lower Michigan. With 850 mb temps to around
-5C (lake sfc temp near 12C) instability supported scattered to
numerous lake effect rain showers.

Tonight, continued CAA will drop 850 mb temps to near -7C. Even with
some mid level drying, inversion heights remaining around 7k-8k
ft with lake induced CAPE values of 300-400 J/Kg will maintain
lake the lake effect pcpn. Forecast wet-bulb zero heights also
will support a mix or change to snow over inland locations,
especially with elevations over 1200 ft. The convective/moisture
layer also looks just deep enough to support mainly snow rather
than dz/fzdz. Temps dropping into the upper 20s to lower 30s may
allow some snow to accumulate to around an inch with some brief
slushy roads with slipper spots especially on bridges.

Friday, as winds become lighter lake induced troughing and stronger
low level convergence is expected to develop focusing the heavier
pcpn and greater coverage along or near the shore in Marquette
county during the morning. By afternoon, diurnal heating and an even
weaker gradient will favor mainly just sct/isold rain showers mainly
over inland locations in the west. Highs still struggle back  into
the lower 40s north to the upper 40s south.

.LONG TERM...(Friday night through Thursday)
Issued at 406 PM EDT THU OCT 1 2020

Mid to upper level troughing will continue over the Upper Great
Lakes through most of the weekend with cooler temperatures and
periods of mostly lake-effect rain showers but can`t rule out some
snowflakes mixed in Friday night into Saturday. Troughing finally
begins to lift away Sunday with a shortwave approaching before brief
ridging and zonal flow Beginning early next week, the pattern
briefly becomes more zonal flow Monday into Tuesday. Latest guidance
continues to show another shortwave and cold front Tuesday and
Wednesday which will bring next chance of showers and temperatures
dipping back to around or just below normal for this time of year.

With that upper-level low still hanging around Friday night and with
enough moisture and inversion heights being around 800-900mb, still
could expect some lake-effect rain showers to occur with a few snow
flakes mixed in. Winds will be subsiding as well which should limit
the coverage of any lake-effect precip and should end late Friday or
early Saturday. Have continued to have slight PoPs in the for the
lake-effect.

A shortwave will approach Upper Michigan late Saturday into Sunday,
which may end up tracking just south of Upper Michigan and may keep
showers out of the cwa. Either way, the upper-level trough will
linger into Sunday morning before finally starting to move away from
the region. In its wake, developing weak north-northeast flow could
be some isolated lake effect rain showers, mixing with some
snowflakes/graupel inland late Saturday into Sunday morning before
drying out by Sunday afternoon.

A brief period of rising heights and waa thanks to ridging over the
west-central CONUS, will make the flow more zonal by Monday with
drier conditions and southwest waa flow and as a result ahead of the
next shortwave, breezy southwest winds is a possibility. 12z GFS is
running high compared to the Canadian and ECMWF so we`ll see how
this trends over the coming days. With 850mb temps between 5C-7C,
this will result in mid to upper 50s for highs. Another shortwave
with an associated cold front, looks to move through late Tuesday
into Wednesday with southwest flow changing to northwest flow behind
the shortwave. Temperatures Tuesday will be around the 60 degree
mark but slowly cooling down by Wednesday into Thursday with mostly
lower 50s.
&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 746 PM EDT THU OCT 1 2020

Thru Fri, cold northerly flow across Lake Superior will lead to lake
effect -shra/-shsn affecting KIWD/KCMX/KSAW at times. Some of the
showers may be heavy enough to drop vis briefly to MVFR. Expect cigs
to settle into MVFR tonight, but there will be periods of VFR. Pcpn
will change back to just -shra during Fri, and cigs at all terminals
will return to prevailing VFR.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 409 PM EDT THU OCT 1 2020

Expect winds to remain elevated from the north into tonight with
continued CAA, but slowly diminishing to around 20 knots by
tomorrow morning as sfc high pressure moves in from the west. This
high pressure persists through the weekend. Models are suggesting
a trof to pass over Lake Superior on Tuesday evening, which may
bring an increase in winds from the SE to 25 knots ahead of the
trof, becoming NW behind the trof to around 25 knots as well.
&&

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

$$

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




Area Forecast Discussion

National Weather Service Pueblo CO

 306 PM MDT Thu Oct 1 2020

.SHORT TERM...(This evening through Friday)
Issued at 306 PM MDT Thu Oct 1 2020

Current water vapor imagery and upper air analysis is indicating
weak to moderate northwest flow aloft across the region, with a
broad upper trough in place across the central CONUS and upper level
ridging across the West Coast. Water vapor imagery is also
indicating eastern Pacific energy topping the ridge across the
Pacific Northwest Coast and translating into the Intermountain West
at this time. GOES visible imagery is indicating an active smoke
plume from the Mullen wildfire of south central Wyoming, which as of
yesterday crossed into north central Colorado. However, we are not
currently seeing much smoke across south central and southeast
Colorado, with the higher terrain west of the I-25 Corridor clearly
visible, though a touch hazy. Temperatures are indicating a taste of
fall today, with current readings mainly in the 50s and 60s
areawide.

Tonight-Friday...Northwest flow aloft progged to increase slightly
through the day tomorrow, as energy topping the ridge continues to
translate across the Northern Tier and into the Upper Midwest.
Models do indicate some increasing high level clouds across the
region through the overnight hours, though clouds to be generally
thin enough to allow for another night a strong radiational cooling
with lows at and below seasonal levels, coldest across the valleys.
The main concern continues to be how much smoke and how thick it
will be as it moves across eastern Colorado tonight and through the
day tomorrow. The HRRR smoke forecast remains very bullish at
increasing the vertically integrated smoke column across the Pikes
Peak region and southern portions of the I-25 Corridor through the
evening, with the greatest concentration of smoke then pushing out
across northern portions of the southeast plains through early
Friday morning before the elevated smoke mixes to the surface later
Friday morning and afternoon across southeast Colorado. With that
said, have kept areas of smoke in the forecast across eastern
Colorado through the period, though will need to continue to monitor
smoke and visibility trends across northern Colorado to see how and
if these trends could lead to restrictions to visibility across
southern areas. Also depending on how thick the smoke may be
tomorrow, highs should warm back up above seasonal levels with
expected highs in the 70s and lower 80s across the southeast plains,
with mainly 50s and 60s across the higher terrain.

.LONG TERM...(Friday night through Thursday)
Issued at 306 PM MDT Thu Oct 1 2020

Dry conditions prevail through the extended.

Friday night and Saturday...The ridge of high pressure will continue
across the western US into the weekend, with a two-part dry cold
front forecast to push through the area starting Fri night. The
initial cold front will drop south across the eastern plains Fri
evening, then a stronger surge of cold air is expected to push in
Sat morning. This will drop high temps on Sat into the mid 60s to
lower 70s for most areas.

Sunday through Tuesday...The high pressure ridge begins to flatten
on Sunday as a stronger upper wave crosses the Pacific NW and the
northern Rockies Sun eve through Mon. Temps will rebound for Sun,
become extremely warm for Mon, then cool a couple of degrees for Tue
as the upper flow decreases. High temps will remain in the 70s each
day for the high valleys, but will vary a bit for the plains. On Sun
expect max temps in the 70s to near 80F. Mon the mercury jumps up
into the mid to upper 80s, but thankfully winds are not anticipated
to be strong enough to warrant any sort of fire weather highlight.
Tue forecast highs for the plains will then be in the mid 70s to
lower 80s.

Wednesday and Thursday...The weakening ridge begins to gradually
slide to the east, with the ridge axis crossing Colorado Wed eve.
Expect warm temps to persist, with highs across the plains hovering
in the lower to mid 80s. Moore

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 306 PM MDT Thu Oct 1 2020

Generally VFR conditions with light diurnal wind regimes are
expected at COS, PUB and ALS over the next 24 hours. For COS, PUB
and eastern Colorado, will need to continue to monitor upstream
smoke and vis trends, as smoke from south central Wyoming and north
central Colorado wildfires could bring an increase in smoke, and
potential restrictions to vis, late tonight and through the day on
Friday.

&&

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

$$

SHORT TERM...MW
LONG TERM...MOORE
AVIATION...MW




Area Forecast Discussion

National Weather Service Blacksburg VA

 907 PM EDT Thu Oct 1 2020

.SYNOPSIS...
A frontal boundary will slide east across the piedmont tonight
and offshore early Friday. High pressure works in for the start
of the weekend. Another cold front enters the region later
Sunday into Sunday night.

&&

.NEAR TERM /THROUGH FRIDAY/...
AS of 907 PM EDT Thursday...

A cold front will move southeast across the region tonight
into Friday morning. High pressure will build in behind the
front Friday. Scattered showers continue to form along the
frontal boundary with the moisture convergence. For this
update, extended the duration and coverage a little of showers
along the boundary tonight. Also modified temperatures and low
readings for overnight into Friday.


As of 650 PM EDT Thursday...

Surface frontal boundary will move southeast across the region
tonight. Scattered showers will developed with the surface
convergence along the front. The best chance will be in the
southeastern portion of the forecast area. Made a few
adjustments to pops and weather to capture radar trends and
blend in the HRRR for this evening into tonight. Modified
temperatures tonight utilizing the latest surface obs, their
trends and mixed in the NBM. more changes later...


As of 200 PM EDT Thursday...

High-res models are still favoring shower development mainly east of
the Blue Ridge this afternoon as low works north along a cold front,
coincident with strengthening shortwave into the central
Appalachians. However, moisture is limited in this airmass. Given
the strength of the shortwave and strong convergence along the
front, will maintain chance pops mainly east of the Blue Ridge, to
low likelys east of Lynchburg. Rainfall will be light overall, with
a few locations attaining a quarter inch at best. Lack of
instability leads to no thunder.

Shower chances will be highest in the 7pm to 11pm time slot.
Clearing takes place west to east this evening into the morning
Friday. Lows tonight will range from the lower 40s west to upper 40s
to lower 50s east. High pressure works in Friday with cold air advection
and lower dewpoints. Despite sunshine, high temperatures will run from
the 50s in the mountains, to the 60s east.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 200 PM EDT Thursday...

Expect quiet weather to persist into the first part of the weekend.
However, guidance is in good agreement with a progressive upper trof
pushing a weak surface low through the Ohio valley and dragging a cold
front through the area. This will bring a good chance of showers back
to the forecast by late Sunday and into Sunday night, especially west
of the Blue Ridge.

Temperatures will remain a good bit below normal through the weekend.
Highs will generally be in the mid/upper 60s east of the Ridge with
lower 60s to the west. Lows Friday night will be chilly with lower 40s
east, 30s west and some frost possible as the normally colder locations
may dip to around the freezing mark. Lows then slowly moderate
through the 40s over the weekend.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 200 PM EDT Thursday...

Guidance is in generally good agreement in developing a low amplitude,
progressive upper flow regime which eventually trends to a western
ridge and an eastern trof. So after any lingering showers early on
Monday dissipate, it looks like generally quiet weather through the
middle of next week before another cold front brings some blustery
conditions and a chance of showers back to the forecast toward
Wednesday night.

Temperatures look to be close to seasonal norms through the period.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
As of 730 PM EDT Thursday...

A cold front will travel southeast across our region tonight
into Friday morning. High pressure will build in for the
weekend. Scattered MVFR showers are possible along the frontal
boundary especially during the next couple of hours. Behind the
front VFR conditions will prevail tonight into Friday.

Above average confidence for ceilings, visibility and wind.


.Extended Aviation Discussion...

Mainly VFR conditions through the period. A frontal boundary
arrives late Sunday into Monday which may bring a few showers
and sub-VFR to the mountains. Dry weather is expected for
Tuesday.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$
SYNOPSIS...WP
NEAR TERM...KK/WP
SHORT TERM...MBS
LONG TERM...MBS
AVIATION...KK/WP




Area Forecast Discussion

National Weather Service Las Vegas NV

 240 PM PDT Thu Oct 1 2020

.SYNOPSIS...A strong ridge of high pressure over the western states
will lead to near-record highs through Saturday. North breezes can
be expected through Friday, especially down the Colorado River
Valley. Conditions will remain warm and dry through the weekend and
at least the middle of next week.
&&

.SHORT TERM...through Friday.

With strong high pressure overhead, temperatures will remain several
degrees above normal into early next week. It`s possible that Las
Vegas could reach 100 degrees Friday and just a slight chance of
Saturday as temperatures are forecast to drop slightly. Gusty north
winds down the Colorado River Valley have diminished slightly, but
are still expected to remain elevated into this evening. Some north
winds are expected again Friday, but overall speeds should be lower.

The latest HRRR Smoke Forecast indicates wildfire smoke from the
southern Sierra will be directed away from Inyo County and southwest
Nevada today through most of Friday to the east-southeast flow in
the H7-H5 layer. However, there is some indication that smoke may
start to impact the northern portions of the Owens Valley as early
as Friday night into Saturday.

.LONG TERM...Saturday through Wednesday. High pressure remains in
control through the period, leading to a continuation of dry weather
with temperatures well above normal for early October. There are
some hints of a possible pattern change beyond this time frame, but
there is a lot of uncertainty regarding the strength and position of
a cold low pressure system in or near the Gulf of Alaska as well as
the remnants of eastern Pacific Hurricane Marie. Will continue to
monitor.
&&

.FIRE WEATHER...With strong high pressure overhead temperatures will
reach near records through Saturday. Temperatures will start a slow
cool down into next week, but will still remain several degrees
above normal. Conditions are also expected to remain dry with single
digit RHs in the afternoon and generally poor to moderate recoveries
overnight. Other than some gusty northerly winds down the Colorado
River Friday, the remainder of the area is expected to see typical
diurnal winds.
&&

.AVIATION...For McCarran...Generally diurnal wind patterns are
expected through Friday with afternoon northeasterly winds in the 8-
10 knot range. Clear skies are expected.

For the rest of southern Nevada, northwest Arizona and southeast
California...Little impacts expected through Friday other than some
gusty north winds down the Colorado River Valley. Smoke is expected
to stay west of the Owens Valley through Friday evening, but there
is some potential of smoke moving into the area by early Saturday
morning bringing some reduced visibility.
&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&

$$

SHORT TERM...Gorelow
LONG TERM...Morgan
AVIATION...Gorelow

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