Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/30/21

Area Forecast Discussion

National Weather Service Binghamton NY

 956 PM EDT Fri Oct 29 2021

.SYNOPSIS...
Rain showers are moving into the area this afternoon, and will
continue through tonight. Scattered showers are expected
Saturday, possibly lingering into Sunday. Temperatures will
trend cooler early next week.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...

Drier air continues to hang in tough across areas from I-81
eastward late this evening. As a result, timing of the showers
looks a little slower for these locations tonight. Still a few
rounds of rainfall are anticipated. Rainfall amounts so far in
the watch area are from 1/2 to 1 inch. The HRRR and Hires NAM
both bring the heaviest rainfall during the mid and late evening
hours with the forecasted totals on track around 1.5 inches. We
have received several reports of flooded roadways and flash
flood warnings have been issued into the overnight. Turn around
don`t drown. The good news is a dry slot is still advancing
northward this evening as expected which will lead to more
showery rainfall overnight. Previous discussion below.



200 PM Update...

Clouds are overspreading in the area with light rain finally
starting to work into the western Twin Tiers. A vertically
stacked low continues to slowly move northward through the Ohio
valley. An occluded front extends from the center of the
cyclone (approximately over Ohio/WV/northern KY) eastward to the
mid- Atlantic coast. The satellite-derived total precipitable
water product indicates a plume of PWATs up to 1-1.5in extending
inland towards the center of the low, courtesy of a
strengthening low-level jet that is helping us tap into some
Atlantic moisture.

Models continue to move the main area of steady, moderate to
locally-heavy rain through rather quickly this evening. That,
along with wind shadowing/downsloping east of the Poconos-
Catskills, is supporting the continued downtrending of rainfall
expectations for areas along and east of I-81. Expect totals
generally under an inch for most of the area, with the burnt of
the activity between 00Z and 06Z.

That said, steadier, occasionally heavier rainfall will be
possible for a longer duration west of I-81 and south of the
Finger Lakes tonight. The axis of deeper moisture pivots
westward as the low continues to slowly move northward.
Meanwhile, the low level jet will cause orographic enhancement
as it upslopes against the Allegheny plateau. Thus, rainfall
amounts could exceed an inch for the southern Finger Lakes, as
well as Steuben, Chemung, and Bradford counties These areas are
already very wet and sensitive to additional rainfall; new rain
will almost immediately run off into creeks/small streams. That
is where there is a bit more concern for a somewhat organized
flooding potential, compared to a more marginal threat
elsewhere. A Flash Flood Watch has been issues for Steuben,
Bradford, and Chemung counties.

The stacked low will continue its northward track, moving into
western NY and PA into early Saturday. This more northerly than
northeasterly track means a dry slot aloft is likely to lift
over our region Saturday. Showers can still be expected, but
they will tend to be scattered/on- and- off and with limited
amounts. Responses to the heavier rainfall, from overnight, will
still be ongoing for the main stem rivers. There is a small
chance of a couple river points going back to near minor flood
stage, but most will stay below. Meanwhile, the persistently
high water levels on Cayuga and Onondaga Lake will continue.
After lows of mostly 40s tonight, highs of 50s-near 60 are
anticipated for Saturday.

Stray showers continue through Saturday night with the upper low
directly overhead. Chances will be better across our
northeastern zones as a low closes off along the mid Atlantic
coast and quickly tracks into New England by early Sunday
morning. Otherwise, expect lows to drop back into the mid and
upper 40s under cloudy skies.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
315 PM Update:
Upper level troughing will slowly lift northeast on Sunday
(Halloween), with most of the steadier rainfall moving out of
the far eastern counties early in the morning. While this may be
followed by a few breaks of sunshine, it`ll be brief, with
cyclonic flow aloft and weak cool advection with winds off the
Great Lakes promoting increased cloud cover and some spotty
light showers or sprinkles again in the afternoon as a weak
shortwave trough rotates through. Showers will diminish again
around sunset, and while a brief shower can`t be completely
ruled out in the evening, it will be mostly dry, with seasonal
temperatures.

An upper trough moving across southern Ontario into Quebec will
drop a weak cold front through the area late Sunday night, with
additional light showers possible starting after midnight,
mainly west of I-81. The front itself will be near the Hudson
Valley by Monday morning, with slightly cooler and drier air
spreading across the area in its wake. Partly Sunny skies will
prevail for most areas on Monday, except for parts of Oneida
County, where lake effect clouds will linger.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
315 PM Update:

Most of the Northeast and Mid Atlantic will be on the edge of
longwave troughing persisting across eastern Canada through the
period. This will keep somewhat cooler than normal temperatures
in place (highs in the upper-40s to lower-50s, versus the
average of middle to upper 50s). No significant precipitation is
expected, but occasional light showers are possible as a few
weak disturbances roll by. The first one arrives late Tuesday,
with lake effect showers lingering in its wake (mainly west of
I-81 in NY). Another sharper shortwave rolls through on
Wednesday, bringing the chance of showers to most areas
(including NE PA) before Noon, with lake effect lingering in NY
through the afternoon. Precip may be a rain/snow mix Tuesday
night into Wednesday morning, but coverage and QPF will be low,
with minimal impacts expected.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Rain is moving through the region from SW to NE this evening
with intermittent IFR restrictions likely at all terminals as
it moves through. ELM, ITH, AVP, and BGM will be impacted
between now and 3z while it will take till 2 to 3z to get to SYR
and RME with restrictions. A few rain showers ahead of the line
could impact RME and SYR but will likely not result in any
restrictions with how dry the low levels are ahead of the rain.
A strong low level jet will also be associated with the rain
with BGM, RME, and AVP having the best chance of reaching LLWS
criteria.

Behind the rain, low stratus will keep Fuel alternate to border
line IFR conditions at all terminals with continued rain
showers at times through the late morning. With day time
heating, cigs will rise a bit but VFR conditions are unlikely at
most terminals but AVP where the added benefit of downsloping
will help raise the cigs by the late afternoon.

Outlook...

Saturday afternoon through Saturday night...Restrictions likely
as low pressure system finishes moving through the region with
scattered showers and fuel alternate to at times IFR ceilings.

Sunday through Sunday night...Scattered rain showers and
occasional restrictions possible; mainly Central NY terminals.

Monday through Monday night...Mainly VFR.

Tuesday through Wednesday...Restrictions possible in passing
showers, which may mix with snow during the overnight hours.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Flash Flood Watch until 5 AM EDT Saturday for PAZ038.
NY...Flash Flood Watch until 5 AM EDT Saturday for NYZ022-024.

&&

$$
SYNOPSIS...HLC
NEAR TERM...HLC/MDP/MWG
SHORT TERM...MPH
LONG TERM...MPH
AVIATION...AJG



Area Forecast Discussion

National Weather Service Caribou ME

 917 PM EDT Fri Oct 29 2021

.SYNOPSIS...
High pressure will ridge across the region tonight. Low
pressure will approach on Saturday and cross the area Sunday.
The low will move northeast on Monday. High pressure will build
in from the west later Monday into Tuesday. Weak low pressure
will pass south of the area Tuesday night into Wednesday.

&&

.NEAR TERM /THROUGH SATURDAY/...
9:17 PM Update: A surface ridge of high pressure covers the
area this evening. The ridge will only move very slowly east
overnight. The HRRR and SREF continue to hit on the idea that
low clouds form very late tonight or early Saturday morning
across most of the FA. At this time there is just one small area
of clouds in eastern Washington County with a clear sky
elsewhere. The temperatures have dropped off rapidly this
evening with many of the northern valleys below freezing.
Temperatures in some spots have dropped below forecast lows, and
have made some adjustments to the hourly temperatures and
forecast lows. Temperatures will likely rise very late tonight
if the lower clouds materialize. Otherwise, no significant
changes are planned.

Previous discussion:
High pres to the nne will hold on through tonight keeping dry
air in place keeping alleviating any cloud cover until the early
morning hrs on Saturday. This will allow a clear skies over the
CWA through at least midnight or so, until a return flow sets
up around the high allowing for llvl moisture to be advected n
overnight. The clear skies and cold temps look to be a nice
setup for viewing the Aurora later in the evening and later
tonight. This will depend on how quickly the clouds move in. The
latest visible satl imagery does confirm some some lower clouds
setting up in swrn New Brunswick and off off the coast. This
cloudiness is shown by some of the high resolution guidance,
including the NAMNEST and HRRR, to move into the coastal and
Downeast region overnight and then spread as far n as Aroostook
County by around daybreak or just before. Temps will drop
quickly after sunset w/readings dropping into the upper 20s and
lower 30s across the northern 1/2 of the CWA, while central and
downeast areas see mid to upper 30s. The exception to this will
be the coast where overnight temps remain in the 40s. Given the
light ESE flow setting up during the early morning hrs,
expecting some fog to set up. Also, given the deep llvl moisture
w/ESE flow and drier air aloft, expecting some drizzle near or
just after daybreak, especially across the wsw areas(upslope).

For Saturday, a coastal front sets up ahead of the low lifting
up from the s. The ESE flow is expected to increase w/drizzle
and periods of light rain expanding to the n as. Rain will start
moving N by the afternoon as the mdl sndgs show the column
moistening up w/low pres lifting up into srn New England. Cooler
than the previous days with temps running near normal.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Low pressure cutting west of the area Saturday night into Sunday
will bring a period of moderate to heavy rain and above normal
temperatures. The heaviest rain is expected from about midnight
Saturday night to 8 AM Sunday. Isolated thunder is also possible
across Downeast Maine given strong forcing and a few hundred
joules of elevated instability. A 60 to 70kt low level jet will
also accompany the precipitation, creating breezy conditions
along the coast. Gusts in excess of 40 mph are possible along
south facing hills and channels of coastal Hancock and
Washington Counties. Rainfall amounts will range from just under
an inch across the north, to 1 to 2 inches across upslope
favored regions of the Central Highlands and into Downeast
Maine. Fallen leaves, particularly across Downeast Maine, may
lead to clogged storm drains and localized flooding early Sunday
morning.

A dry slot will quickly work into the area Sunday afternoon;
Precipitation will linger longest across the far north, where
showers will remain possible Sunday night. Brisk west flow and
lingering low level moisture will lead to isolated to scattered
rain showers across higher terrain of the North Woods and
Central Highlands. Another shortwave will clip northwestern
Maine Monday morning, leading to a chance of showers. Cooler air
will be slow to filter in behind the low, leading to continuing
above normal temperatures with highs in the 50s.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Troughing across eastern Canada and into the northeastern U.S.
will favor near to below normal temperatures and an unsettled
pattern next week. There will be a few opportunities for areas
to observer their first snowflakes of the year, particularly
across northern Maine. Dry air aloft Monday night will gradually
erode later Tuesday into Wednesday as a subtle shortwave trough
moves across the area, leading to a slight chance of rain and
snow showers. Uncertainty increases later in the week as most
guidance shows a noreaster developing during the period from
Thursday through Saturday, but there is little agreement with
respect to timing and positioning. The antecedent air mass will
generally favor snow across the north and a mix elsewhere if the
low tracks close enough to the coast to produce precipitation.
Despite the uncertainty, roughly 60 percent of ensemble members
from the 0z ECMWF and 12z GEFS have accumulating snow in Caribou
by next Saturday evening, November 6th.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR for all the terminals late this evening w/light
and variable winds. MVFR/IFR cigs look to set up after midnight
for KBHB and KBGR and then spread n into the northern terminals
around 09-11Z.

For Saturday, IFR cigs for all terminals early Saturday w/some
drizzle and fog. Some gradual improvement to MVFR across all
the airfields by afternoon. Light ESE wind increasing to 5-10
kts.

SHORT TERM: Saturday night into Sunday AM...MVFR early, then
IFR with LLWS likely. Rain, heavy at times, with a an isolated
thunderstorm also possible. ESE wind 5 to 15 kts with gusts to
25 kts.

Sunday PM to Sunday night...MVFR with showers. S winds 5 to 10
kts with gusts to 20 kts.

Monday to Tuesday...VFR with WSW winds 10 to 20 kts with gusts
to around 30 kts.

Tuesday night to Wednesday...Mainly VFR with W winds 5 to 10 kts
with gusts to 20 kts. A slight chance of rain and snow showers.

&&

.MARINE...
NEAR TERM: NE winds 10-15 kts becoming E tonight over the outer
zones, while the intra-coastal zone sees 5-10 kts. Seas will
average 2-4 ft.

For Saturday, some fog and drizzle early w/rain pushing in from
later in the day. E wind increasing to 15-20 kts w/seas building
to 4-5 ft. Some gusts to 25 kts are possilbe later in the
afternoon over the outer zns.

SHORT TERM: A gale is expected across the waters Saturday night
into early Sunday morning with seas up to 12 feet and a period
of heavy rain reducing visibility. Conditions improve to SCA
Sunday afternoon and evening, then fall below SCA late Monday
through Wednesday.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Gale Watch from Saturday evening through Sunday morning for
     ANZ050>052.

&&

$$

Near Term...CB/Hewitt
Short Term...MStrauser
Long Term...MStrauser
Aviation...CB/Hewitt/MStrauser
Marine...CB/Hewitt/MStrauser



Area Forecast Discussion

National Weather Service Glasgow MT

 812 PM MDT Fri Oct 29 2021

.DISCUSSION...
Cold frontal passage this evening has drastically brought a
change in airmasses to the area. The tranquil mild airmass was
replaced in Glasgow where the temperature dropped 12 degrees in
less than an hour and north winds gusted to over 40 mph.

Have blended going forecast with HRRR and other Near-term models
that are handling this cold front better. Precipitation this
evening along the Canadian border may amount to near or over a
tenth of an inch, but no snowfall is expected at this time. TFJ

Previous Discussion...
Several record highs have already been set this afternoon in
Northeast Montana, including Glasgow`s 76 (so far, as of 2:30 pm
MDT) which breaks the previous record of 74 from 1915. Today`s
"heat" will quickly be replaced by colder temperatures tonight and
tomorrow as a cold front sweeps through the area.

Short term (tonight through Saturday)...
The cold front will move through the area this evening, with
northwest winds expected area-wide by midnight tonight. Gusty
northwest winds will continue through the day on Saturday before
beginning to taper off overnight Saturday night and Sunday
morning. Rain showers should also accompany the front, with the
rain changing to snow generally north of the Missouri River
overnight tonight into Saturday morning. There should be just
enough moisture left over tomorrow afternoon to pop a few showers
for the CWA (and maybe produce a few flakes of snow north) before
clearing out tomorrow evening.

Longer term (Saturday night through next week)...
The northwest winds should continue into Sunday, but be lighter
than tonight and Saturday. For trick-or-treat time Sunday night,
temperatures will be in the 20s and 30s.

As far as the pattern for the extended, Northeast Montana will be
caught between a ridge with its axis running from the Pacific
Northwest into British Columbia and Yukon Territory in Canada, and
a trough near/over the Great Lakes. The net result for the CWA is
temperatures generally in the ballpark of normal--or slightly
cooler than norms--for late October and early November. Dry
weather is also expected to persist once the precip in the shorter
range moves out.

97

&&

.AVIATION...
UPDATED 2000Z

FLIGHT CONDITIONS: MVFR at times late evening and overnight
through Saturday morning. VFR expected again during the day on
Saturday.

WINDS: Strong North winds this evening occurred at KGGW and KOLF.
These will likely affect KGDV and KSDY areas at about 05z but with
lighter speeds but a gust to 30 kts is still possible. Look for
NW 15-25 kts Saturday.

SYNOPSIS: A cold front will exit the area by late tonight.
Rainshowers will be brief at KGGW and KOLF this evening. Cloudy
but brisk/windy conditions are expected Saturday. TFJ

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 10 AM MDT Saturday For Fort Peck Lake
for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow



Area Forecast Discussion

National Weather Service Green Bay WI

 1055 PM CDT Fri Oct 29 2021

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Saturday
Issued at 234 PM CDT Fri Oct 29 2021

The latest RAP analysis and satellite/radar imagery show a large
occluded cyclone spinning over Kentucky/Tennessee, but the
cyclonic flow around this low pressure system extends across most
of the western Great Lakes. Widespread cloud cover continues to
blanket Wisconsin early this afternoon though showers and drizzle
have mostly diminished. Partial clearing has occurred over
northern Minnesota close to the axis of surface high pressure.
Winds have also increased starting around late morning with gusts
into the lower to middle 30s. As the low lifts northeast over the
southern Appalachians, cloud and wind trends are the focus of the
forecast.

Tonight...Cyclonic flow will continue across northeast Wisconsin
as low pressure lifts northeast towards West Virginia. Subsidence
will increase aloft as drier air associated with the upstream
surface high/mid-level ridge axis slides slowly east. However, low
level northeast flow off Lake Michigan and Lake Superior will
likely keep moisture trapped below the inversion, which will favor
mostly cloudy skies across the region. Some breaks may develop,
like what occurred over Minnesota this morning. Wind gusts to 30
mph may linger over eastern WI as well, particularly in the
evening, but will see a general diminishing trend through the
night. Lows will range from the upper 30s to middle 40s.

Saturday...The low pressure will gradually weaken as it mosies over
the central Appalachians. Cyclonic flow will be much weaker than
today, and should therefore see dry air have a greater influence.
After a mostly cloudy start, statistical and model guidance favor
decreasing clouds through the day. With some sunshine, temps will
rise into the middle to upper 50s.

.LONG TERM...Saturday Night Through Friday
Issued at 234 PM CDT Fri Oct 29 2021

Fairly quiet weather expected through much of the long-term portion
of the forecast. Temperatures will drop a few degrees below normal
and some light lake effect rain and snow showers will be possible,
mainly downwind of Lake Superior.

Saturday night through Sunday: A very brief/dry surface ridge and
upper-level ridge will pass through the area Saturday night. This
will effectively keep much of the area dry under mostly clear skies.
Late Saturday night into Sunday morning, a fairly strong cold front
is expected to pass through the area from west to east. This will
usher in colder air for the beginning of the work week along with a
few sprinkles or flurries. The increased cold air advection, along
with gusty winds just above the surface, will lead to more of a
breezy/blustery day Sunday. Latest guidance would suggest that winds
may gust as high as 30 mph from the northwest through much of the
day. Overnight lows are forecast to drop into the low to mid 30s
central/north-central and the upper 30s to around 40 elsewhere. High
temperatures will be in the 40s to around 50 for Halloween.

Sunday night through Tuesday night: An upper-level closed low will
set up across much of Ontario and drift slowly eastward through
this time period. The increased moisture associated with this
feature along with shortwaves sliding around the periphery, will
allow for intermittent chances for light lake effect rain/snow
chances, mainly downwind of Lake Superior. The best chances for lake
effect will be as the aforementioned waves pass through the area;
however, the exact timing will be difficult to determine this far in
advance. Overall moisture doesn`t look overly impressive, but may
result in some minor accumulations across north-central. Again, this
will depend on overall wind direction and the amount of moisture
that wraps through the area along with the time of day. Temperatures
will be below normal with lows dropping into the upper teens and
20s. High temperatures will be in the upper 30s to around 40.

Rest of the extended: A surface ridge is expected to build across
much of the area through this time period, which will likely lead to
lower chances for any precipitation as moisture will be limited.
Depending on final wind direction, some continue like lake effect
precipitation or ,at the very least lake effect cloud cover, may
still impact north-central Wisconsin. Temperatures will remain below
normal with overnight lows forecast to be in the upper teens to mid
20s. High temperatures will be in the upper 30s to low 40s. For
comparison, average high temperatures for this time of year are
around 50 and average low temperatures are in the low to mid 30s.
&&

.AVIATION...for 06Z TAF Issuance
Issued at 1055 PM CDT Fri Oct 29 2021

North northeast winds flowing across the Great lakes will keep
MVFR ceilings over most of the area tonight through midday Saturday.
IFR ceilings are possible north of a Rhinelander to Iron Mountain
line. Clearing is expected Saturday afternoon which will continue
into the evening hours. MVFR ceilings could return late Saturday
night.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....MPC
LONG TERM......Cooley
AVIATION.......RDM



Area Forecast Discussion

National Weather Service Twin Cities/Chanhassen MN

 647 PM CDT Fri Oct 29 2021

.SHORT TERM...(This evening through Saturday night)
Issued at 245 PM CDT Fri Oct 29 2021

Two concerns in the short term are the potential for dense fog
tonight/Saturday morning and then the timing of a cold front
Saturday afternoon and it`s potential implications for afternoon
temperatures out toward Alexandria and Morris.

Low that brought us a soggy Thursday is still down in the Ohio
Valley, but we`ve been seeing a surface ridge axis push in from the
Dakotas. Last night, we saw fairly widespread dense fog from north
central into western MN and as this ridge axis crawls east, expect a
similar result under the ridge tonight from roughly Redwood Falls
and Little Falls over to the first tier of counties in western WI.
Dewpoints this afternoon are up near 40, so our crossover temps will
be easily achievable. Basically, once we start seeing areas drop
into the 30s, we`ll start seeing fog form. HREF probs for vis under
1/2 mile is up at 75% along the I-35 corridor, so confidence is
pretty high we`ll see fog. Held off on an advisory though as there`s
uncertainty with how far east the threat will be in WI given the
potential for stratus to be coming back west out of central WI, with
areal extent of dense fog in MN uncertain. Still if you`re in
eastern MN, it`s best to plan on a foggy start to your Saturday.

For Saturday, it will be our last warm day before a cold front
arrives in the evening, bringing our first prolonged stretch of below
normal temepratures this Fall. The HRRR shows temperatures dropping
a good 10-15 degrees in the 2 hours post FROPA, so if the front
comes in faster than currently forecast, it could end up being
several degrees cooler than forecast up in Morris and Alexandria. Did
nudge down highs slightly in eastern MN and western WI as potential
warming may be lost for much of the morning as we burn off the
morning fog/stratus.

.LONG TERM...(Sunday through Friday)
Issued at 245 PM CDT Fri Oct 29 2021

If you like northwest west, highs in the 40s and lows in the 20s,
you will love the weather next week. We`ll see CAA through the day
on Halloween, but after that, little in the way of airmass change is
expected the rest of the week. We`ll be in north to northwest flow,
generally to the west of an upper low over the Great Lakes. So in
place where high pressure likes to reside at the surface. The one
thing that could be a bit different from what the NBM populated with
is the potential for more cloud cover than currently forecast Monday
through Wednesday as we remain in the cyclonic mid-level flow of the
eastern NOAM trough. We may also be able to scare some light precip
out of the clouds, but it would be nothing more than
sprinkles/flurries. This quiet weather looks to have some staying
power as well, with mean h5 heights from the EPS not looking to
support much in the way of active weather until after the 10th of
November.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 647 PM CDT Fri Oct 29 2021

Main concern tonight will be fog, which is most likely to develop
along a corridor centered N-S from RST through MSP and toward DLH.
Some of this could be dense in spots with prolonged LIFR conditions.
This will likely lift into a low stratus deck in the morning and mix
out by late morning/early afternoon. A cold front will move in late
in the period and reach I-35 right around 00Z with gusty northwest
winds following frontal passage.


KMSP...
Fog, possibly dense, expected to develop after 09Z or so and will be
most dense around sunrise. This will burn off/lift through the mid
morning hours. Cold front will be very close to MSP by 00Z.

/OUTLOOK FOR KMSP/
Sun...VFR. Wind NW at 10G20 kts.
Mon...VFR. Wind NW at 10-15 kts.
Tue...VFR. Wind NW at 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&

$$

SHORT TERM...MPG
LONG TERM...MPG
AVIATION...DPH



Area Forecast Discussion

National Weather Service Blacksburg VA

 1008 PM EDT Fri Oct 29 2021

.SYNOPSIS...
A deep upper-level low pressure system centered over far
southwest Virginia will meander/drift very slowly north-
northeast through Saturday then begin to move a bit more quickly
to the northeast Sunday and then lift out of the area Monday.
The presence of the upper low will keep clouds and showers
across the region through the weekend. However, precipitation
will decrease in coverage and intensity steadily through the
weekend. Temperatures will remain near seasonal normals in the
50s and 60s for maximum readings with minimum readings remaining
above normal mostly in the 40s.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
As of 1007 PM EDT Friday...

...Our upper low continues to spin over the region leaving continued
chances for showers and cloudy conditions through the weekend...

Not much change to the current forecast package with just some minor
adjustments in regards to precipitation chances tonight and
visibility concerns.

Our deep closed upper level low continues to spin over our region
tonight with a slow drift to the north and east by the start of the
weekend. This will keep shower chances in place especially in areas
west of the Blue Ridge overnight into Saturday. Activity will remain
light with the heaviest precipitation remaining over the ridges of
of the Alleghany Highlands, Greenbrier Valley, Mountain Empire, and
western North Carolina region.

Moisture will continue to wrap around the upper level low before
it`s departure sometime late Saturday night into the day Sunday.
Once again coverage will be scattered and sporadic as in pinwheels
through the area. No washouts are expected for the start of the
weekend with some locations especially out east of the North
Carolina and Virginia Piedmont getting away totally dry.

Besides the shower chances, the concern for fog remains overnight
into Saturday morning. Coverage will remain patchy with the highest
confidence per hi-res guidance across the Greenbrier Valley and
Alleghany Highlands south toward the New River Valley and western
North Carolina mountains. Visibility in these areas could drop below
3 miles with improvements not until mid Saturday morning.

Overnight lows tonight will remain on the chilly side of things with
low to mid 40s in the mountains to around 50 out east. SOme of the
sheltered valley locations such as Burkes Garden could dip into the
mid to upper 30s for a short period of time.

Temperatures will remain tampered Saturday due to the wedge. CLouds
and spotty shower chances will keep most locations in the upper 50s
to low 60s. If we do get any sunshine similar to what we saw today
temperatures will likely be bumped up by 2-4 degrees getting us into
the low to mid 60s. Confidence remains low though as the closed low
sits overhead.


Moderate confidence remains in the near term period.


Previous Discussion...

The unsettled weather will continue through Saturday as an upper low
lingers.

The deep vertically stacked closed upper low across the region will
drift northeast through Saturday. Mostly cloudy conditions with
scattered showers will continue tonight into Saturday. The HighresW-
ARW,HRRR and RAP were similar with the unsettled weather
tonight. The coverage of showers will increase this evening and
overnight in the north and especially the west as wrap around
moisture returns with low drifting to the north. The dry slot
will shift east of the area with time. Areas of fog will develop
tonight into Saturday morning. Overnight low temperatures will
range from the upper 30s in the mountains to near 50 degrees in
the Piedmont. Low pressure drifts just to the north of the area
Saturday. High temperatures Saturday will vary from the upper
40s in the mountains to the mid 60s in the piedmont.

Moderate confidence in the Near Term Forecast.


&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 100 PM EDT Friday...

By the start of Saturday night, the center of the slow moving closed
upper low is expected to be located somewhere between the western PA
and central VA, heading northeast overnight. As it does, we are
expected low level winds to veer northwest and increase in speed. By
Sunday morning, a well defined northwest flow pattern is expected to
be in place across the region. This will yield downslope compression
across the Piedmont of VA and NC with limited cloud cover. Over the
mountains, especially those of southeast WV, south into northwest
NC, we can expect cloud cover and scattered rain showers. As Sunday
progresses, drier air advection will allow the cloud cover and
showers to decrease in coverage as the day progresses. While winds
are expected to become gusty, they are also expected to remain below
Wind Advisory levels and stay gusty into and through Sunday night.

Heading into Monday, winds will be on the decrease as cooler high
pressure arrives across the region. This high will continue across
the area, but upstream, a cold front will move south into the Ohio
Valley and spill some of its associated cloud cover into northern
sections of the region.

Temperatures during this portion of the forecast will trend milder
each day with low temperatures about ten degrees above normal and
high temperatures around normal on Sunday and around five degrees
above normal on Sunday.

Confidence in the above portion of the forecast is moderate to high.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 100 PM EDT Friday...

During this portion of the forecast, a closed upper level low will
spin across southeast Canada. Its overall position and extent to
which its associated trough axis digs south into the eastern U.S.
varies from model to model. While these differences increase the
most by the end of the week, for Tuesday into Wednesday we expecting
the following transition.

A cold front over the Ohio River Valley will head southeast and
cross our region. There is some model disagreement on how much
moisture/precipitation will be associated with it.

Wednesday night into Thursday, the differences start to increase.
The GFS keeps a more progressive pattern across our region, but its
European and Canadian counterparts offer an upper low that
amplifies south more, keeping the front across the area, and
reinforced by increased moisture from the south and southern stream
shortwave trough caught up with the tail of the upper trough.

By Friday, either the area remains near normal with a nearly zonal
flow across the area, south of the Canadian low, or much colder air
will be spilling into the area in association with the upper trough
axis of the Canadian system still equatorially displaced across
the area.

Our forecast has been favoring the colder and wetter solutions of
the European and Canadian solutions, and we will not deviate far
from our ongoing forecast without just evidence to support a major
change at this time. This colder and wetter solution places scattered
rain and snow showers across the mountains Wednesday into Thursday.

Temperatures during this portion of the forecast are expected to
trend from near to slightly above normal on Tuesday, to near or
slightly below normal conditions, by Friday.

Confidence in the above weather scenario is low.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
As of 735 PM EDT Friday...

     Slowly northeastward meandering upper low will keep
unsettled aviation conditions through the Taf period.


Vertically stacked upper low over far southwest Virginia will
drift slowly north-northeast into central West Virginia into
Saturday.Unsettled conditions will continue with BKN-OVC clouds
west and SCT-BKN clouds east along with scattered to numerous
showers west and widely scattered showers east. Wrap around
moisture will result in an increase in precipitation west
tonight into Saturday,and in the east by Saturday afternoon.

Ceilings...Mostly MVFR to IFR ceilings expected through the
period west of the Blue Ridge overnight and Saturday morning
trending more toward MVFR Saturday afternoon. IFR-LIFR ceilings
expected across the higher terrain of the west.

Visibilities...Generally VFR east to MVFR west with just
scattered clouds and limited showers east with scattered
-RA/-SHRA west increasing overnight/Saturday morning. Some IFR-
 LIFR visibilities can be possible at times across the higher
 terrain of the west.

Winds...Southwest to West winds 5-8 mph will become West to
Northwest through the day Saturday 5-10 mph.

Moderate Confidence in Ceilings,Visibilities, and Winds
during the Taf Period.


Extended Aviation Discussion...

The upper low will begin to move out of the area Sunday with
improving aviation conditions expected. The western areas may
see some periods of MVFR ceilings Sunday into early Monday, but
most areas should return to VFR conditions by Monday and into
Tuesday. The next sub-VFR producing weather system will likely
arrive late Tuesday into Wednesday. MVFR/IFR rain and snow
showers will be possible in the west Thursday.

&&

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

&&

$$
SYNOPSIS...RAB
NEAR TERM...ET/KK
SHORT TERM...DS
LONG TERM...DS
AVIATION...KK/RAB



Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

 754 PM MDT Fri Oct 29 2021

.UPDATE...
Issued at 738 PM MDT Fri Oct 29 2021

Broad upper trof over northern Rockies is moving toward the
northern Plains this evening, as upper ridge is flattened and
pushed to the east. Strong cold front is draped from low over
northeastern MT across southwestern MT. Front will move across the
forecast area after midnight, with very gusty northwest winds and
colder temperatures behind it. Although satellite images show
increasing clouds moving toward the area, UNR 00Z sounding is very
dry, so precipitation will develop behind the front in the cooler
air.

&&

.DISCUSSION...Saturday Through Friday
Issued at 151 PM MDT Fri Oct 29 2021

As the upper trough approaches the region, surface trough and
cold front will begin crossing the Dakotas early Saturday
morning. Northwesterly winds will become strong on Saturday, 20 to
30 mph with gusts up to 40 mph. Forecast winds only marginally
meet Wind Advisory criteria, so will forgo issuing headlines for
now. Highs will range from the lower 40s across northeastern WY to
the upper 50s across south central SD. Models have continued the
trend of later precip and less of it. Deterministic NAM and GFS
keep best lift within the dendritic growth zone well south of our
CWA, across WY/NE. Furthermore, ensembles show generally less than
a 50% chance of exceeding 1 inch of snow over the Black Hills,
and little to no chance of exceeding 3 inches, which is down from
yesterday`s runs. Some light snow accumulations will be possible
over the southern Hills/foothills in the area of convergence;
additionally, the band of snow may skirt portions of northeastern
WY/southwestern SD.

As cold air continues to sink into the region, cooler temperatures
will persist into early next week. Highs will be in the 30s/40s,
with lows in the teens/20s. Chances for precipitation remain low.

&&

.AVIATION...For the 06Z TAFS Through 06Z Saturday Evening
Issued At 740 PM MDT Fri Oct 29 2021

High clouds are beginning to move into the area this evening.
Smoke from a prescribed burn in the southern Black Hills could
still reduce visibility at RAP this evening, but visibility will
improve after winds shift to the southwest. A cold front will move
across the area after midnight with MVFR/local IFR ceilings
developing behind the front. Some light rain/snow is possible over
northeastern WY, the Black Hills, and southwestern SD starting
Saturday afternoon.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

Update...55
DISCUSSION...Pojorlie
AVIATION...55