Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/20/21
Area Forecast Discussion
National Weather Service Aberdeen SD
925 PM CST Fri Nov 19 2021
.UPDATE...
Issued at 925 PM CST Fri Nov 19 2021
Mostly cloudy skies and light winds will remain through the night.
There were some weak returns on radar this evening in central sd.
Still dont expect any precipitation to fall from these clouds
until better lift moves in later tonight. Made some adjustments to
the forecast.
&&
.SHORT TERM...(This Evening through Saturday Night)
Issued at 224 PM CST Fri Nov 19 2021
A weak mid level trough currently over Washington/Oregon, will track
eastward overnight and across the CWA during the morning hours on
Saturday. The area will see increasing cloud cover this evening and
through the overnight, which may keep low temperatures warmer,
especially in central SD, where a few models suggest lows in the mid
to upper 30s. Depending on model used, the mid level trough
appears rather moisture starved, with maybe very light pcpn, or
none at all occurring. The NAM, and NAM based Hi-res model, ARW,
NMM, show more mid level moisture, a better chance for pcpn. The
18Z HRRR also supports pcpn, mainly after 12Z for this CWA. The
GFS and HREF both suggest dry conditions tonight through
Saturday. Kept schc, low end chc pops in the forecast for now
across central SD. A surface high pressure will follow the trough,
bringing cooler temperatures on Saturday with highs in the upper
30s, to the mid 40s. A strong cold front will approach the CWA
late Saturday night with increasing northwesterly winds expected.
.LONG TERM...(Sunday through Friday)
Issued at 224 PM CST Fri Nov 19 2021
A dry forecast continues for the extended. The period opens on
Sunday with below average highs and breezy northwest winds. Arctic
high pressure will build in potentially setting the stage for colder
than forecast Sunday night lows as winds diminish, especially across
the east. For consistency, went with NBM 90th percentile winds on
Sunday, as well. Current model runs keep wind speeds generally below
advisory levels even at the 90th percentile.
Breezes pick up again on Monday/Monday night ahead of the next sfc
low. Upper ridging and good mixing on Tuesday will push highs into
the upper 40s to 50s. Passing sfc low pressure on Wednesday with a
trailing upper trough will see temps fall for the remainder of the
week, especially as arctic high pressure settles in at the sfc again
on Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 558 PM CST Fri Nov 19 2021
Terminals KABR,KATY,KPIR,KMBG
A weak cold front will move through the area overnight. Winds will
begin the evening light and variable but become northerly and
increase to 5 to 10 kts after 06Z and through much of Saturday.
Winds will become light and variable again toward sunset.
VFR conditions are expected through the period. Behind the front,
ceilings may lower to 5000-8000 ft late tonight and Saturday
morning. Skies are expected to become mostly clear during the
afternoon. There will also be a low probability (20-30%) for rain
or snow showers between 09Z- 15Z with the best chance around
KPIR. With a low probability of any precipitation, have not
included in the TAFs at this time.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Mohr
SHORT TERM...SD
LONG TERM...Wise
AVIATION...Schumacher
Area Forecast Discussion
National Weather Service Cleveland OH
339 PM EST Fri Nov 19 2021
.SYNOPSIS...
High pressure centered over the area this evening will move east
to the east coast by Saturday. Deepening low pressure moving
across the Great Lakes region will bring a cold front across the
area Sunday night. High pressure builds across the area Tuesday
and Wednesday.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
Upper-level ridging build into the region this evening into
tonight, allowing for lake effect cloud cover to diminish from
west to east this afternoon into tonight.
The high pressure center will move east towards the Atlantic
coast tomorrow, allowing southerly winds to develop and advect
warmer temperatures to the region. While temperatures will
recover from the recent cold airmass, temperatures are expected
to remain slightly below normal, with highs forecast to be
generally in the mid 40s. An upper-level shortwave trough
approaches the area from west tomorrow afternoon, with the
trough axis located over Indiana and lower Michigan by 18Z
Saturday. Forcing along this feature isn`t expected to be
particularly strong and any showers that develop along this
feature Saturday afternoon/evening across the area will have to
overcome a very dry antecedent airmass. So, while there could be
drizzle and/or light rain showers, am not currently expecting
any measurable rain tomorrow. It is noticeable though that run-
to-run trends in the RAP suggest a stronger, sharper shortwave
trough. If this trend continues, an increase to PoPs may be
needed with the evening update.
This shortwave trough dissipates and passes east of the forecast
area by 00Z Sunday, allowing for quiet weather Saturday night.
Temperatures dip into the 30s overnight though continues warm
air advection with southerly winds should prevent temperatures
from going below freezing.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Cold front will be approaching the region from the west on Sunday
with gusty south to southwest winds ahead of it. Warm advection ahead
of the front should bring rain into the area from southwest to
northeast through Sunday morning then gradually shift eastward with
the cold front that should move into NW PA by Sunday evening. Much
colder air in the wake of the cold front will spill across the warm
lake Sunday night into Monday with lake effect snow expected.
Current thinking is that the primary snowbelt located over NE OH
into NW PA will be the main focus. We do expect to see accumulating
snow with headlines a definite possibility, greatest accumulations
would likely be Monday into Monday night. More details to come over
the next 24-36 hour.
Highs Sunday will be in the 40`s. Much cooler with breezy conditions
Sunday night through Monday night. Lows Sunday night and Monday
night look to be in the 20`s. Highs on Monday mostly in the 30`s.
However where snow accumulates the most in the primary snowbelt
temperatures could struggle to get out of the upper 20`s.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
Lake effect snow looks like it will continue into Tuesday evening
before the low level ridge of high pressure can reach onto the lake
and end the snow. The warm advection on the west side of the ridge
will allow temperatures to recover Wednesday into Thursday. The
increased warm advection ahead of another low moving into the
western Great Lakes Wednesday night into Thursday may allow for some
light precipitation across the region. Models vary on the intensity
of ripples of low pressure moving along the cold front that moves
over Ohio at some point Thursday night into Friday. At this point
will not go more than chance POP`s until models give us a better
clue on what the atmosphere will provide us.
Cool on Tuesday with highs ranging from the lower 30s east to near
40 across NW OH. Warmer Wednesday into Thursday with highs back into
the 40`s. However snow cover from Monday and Tuesday may keep a few
locations in the 30`s across the snowbelt. Friday will be slightly
cooler with thicker cloud cover. Highs should still get into the
lower to mid 40`s. Lows in the 20`s Tuesday night. Wednesday night
and Thursday night should be in the 30`s.
&&
.AVIATION /18Z Friday THROUGH Wednesday/...
VFR conditions are expected through the TAF period. Cloud deck
with 4-5kft ceilings will eroded from west to east this
afternoon through early tonight as high pressure builds into the
area.
Westerly winds of 8-12 knots this afternoon are expected to
diminish to 5 knots or less this evening and tonight. Winds of
8-11 knots out of south develop Wednesday afternoon as high
pressure moves off to the east.
Outlook...Non-VFR possible with widespread rain showers Sunday
into Sunday night. A transition to lake effect snow is expected
Monday, lasting through Tuesday morning.
&&
.MARINE...
Ridge of high pressure over the lake will shift eastward through
Saturday night. So the tighter gradient will relax on the east end
of the lake with waves decreasing into the evening. Have removed the
western portion of the small craft advisory leaving only Geneva-on-
the-lake to Ripley through 00Z. Winds swing around to the south on
Saturday gradually increasing to 15-20 knots. Winds start shifting
to the southwest Saturday night into Sunday as a cold front
approaches from the west. By Sunday night these southwesterly winds
ahead of the front will reach 20 to 25 knots. So a small craft
advisory will be needed at some point late Sunday afternoon into the
evening. The cold front sweeps across the lake Sunday evening with
west to northwest winds approaching 30 knots. Will have to monitor
for a low end Gale. So after the small craft advisory begins Sunday
afternoon/evening we will continue with a lake headline into
Tuesday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for
LEZ145>149.
&&
$$
SYNOPSIS...Saunders
NEAR TERM...Saunders
SHORT TERM...MM
LONG TERM...MM
AVIATION...Saunders
MARINE...MM
Area Forecast Discussion
National Weather Service Corpus Christi TX
618 PM CST Fri Nov 19 2021
.AVIATION...
VFR conditions this evening. A transition to a mixture of MVFR
ceilings/visibilities anticipated for the 09-13z Saturday period,
over the interior Coastal Plains. At some locations, mainly over
portions of the southern Brush Country/Rio Grande Plains, brief
IFR/LIFR conditions may occur. A mixture of MVFR/VFR ceilings
expected by mid morning Saturday, with predominate VFR expected
by mid/late afternoon. Generally light wind overnight/early
Saturday, increasing to moderate onshore flow by mid/late
afternoon.
&&
.PREV DISCUSSION... /Issued 301 PM CST Fri Nov 19 2021/
SHORT TERM (Tonight through Saturday Night)...
Satellite trends today have shown a gradual clearing across much
of South Texas. Clear skies are in place for most of the region
with the exception of the Southern Coastal Bend where low level
clouds are lingering. Water vapor imagery reveals a shortwave
passing through the region but will slide through unnoticed as
moisture is limited. Light northeasterly winds today will shift
around to the east overnight and southeast through the day
tomorrow as the surface high moves towards the east coast. The
return of onshore flow will result in a slight uptick in low level
moisture. This may open the door for some patchy fog to develop
across the Coastal Plains closer to sunrise. Recent RAP guidance
continues to hint at dewpoint depressions closing in tonight with
condensation pressure deficits ranging from 0-5mb. It`s worth
noting that a weak coastal trough looks to take shape across the
Western Gulf. Not expecting much in the way of precip at this time
as moisture will be limited and the best forcing will remain to
our south. Otherwise, we will be bit warmer tomorrow as onshore
flow persists with highs topping out in the upper 70s to around 80
degrees. Lows tomorrow night look to fall into the low to mid 60s.
LONG TERM (Sunday through Friday)...
Beginning of the long term forecast remains pretty consistent with a
cold front forecast to move through the area Sunday night. Ahead of
the front temperatures will warm into the mid 80s for most of the
region. We will not have had a lot of time for moisture to return
to the region, however the front itself should bring moisture
sufficient moisture with it to produce a scattered showers and
perhaps a few thunderstorms, mainly in the overnight period Sunday
night into Monday morning. Behind this front temperatures fall back
to around 70, give or take a few degrees for the area. Onshore flow
returns Tuesday night into Wednesday to bring a gradual increase in
moisture and temperatures to the area.
From here out the forecast gets more tricky with a lot of
inconsistencies between model runs and between models themselves.
The GFS has been cutting off an H5 low over Mexico Thursday into
Friday, the Canadian is much more progressive, pulling the trough
straight through the region. The ECMWF had previously been on the
side of the Canadian, but the most recent 12Z is trending toward the
slower solution. That said, will go with a blend of models through
the end of the period. NBM is heavily weighted toward the faster
solution, so have gone a bit warmer than this on temps. Summing up
the uncertainty...we could see a front as early as Thursday
afternoon or as late as sometime over the weekend. Regardless of
timing, the moisture supply looks more promising with this front,
and could see a better coverage of showers and thunderstorms.
MARINE...
A weak to moderate northeasterly flow will continue to shift
around to the east this evening before becoming southeasterly
tomorrow morning. This weak to moderate onshore flow will persist
through the day Saturday with a gradually weakening trend during
the overnight hours as we head into Sunday. Weak onshore flow
will persist Sunday before another cold front moves through the
area Sunday night bringing strong offshore flow in its wake.
Isolated to scattered showers with isolated thunderstorms will be
possible Sunday night into Monday before dry air surges in behind
the front. Weak onshore flow returns on Tuesday, increasing to
moderate to strong levels on Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 56 80 65 83 57 / 0 0 0 20 40
Victoria 51 79 61 83 54 / 0 0 0 20 40
Laredo 55 80 65 84 60 / 0 0 0 10 40
Alice 52 81 61 86 57 / 0 0 0 20 40
Rockport 60 79 69 79 58 / 0 0 0 20 40
Cotulla 52 81 63 84 56 / 0 0 0 10 30
Kingsville 55 80 63 85 57 / 0 0 0 20 40
Navy Corpus 63 79 71 79 60 / 0 0 0 20 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
WC/87...AVIATION
Area Forecast Discussion
National Weather Service Marquette MI
534 PM EST Fri Nov 19 2021
.SHORT TERM...(This evening through Saturday)
Issued at 443 PM EST FRI NOV 19 2021
Water vapor imagery and RAP analysis show that the mid-level trof
that aided the LES yesterday is now over Quebec/New England. From
the Great Lakes toward the Pacific NW, flow is more zonally
oriented. Several shortwaves are noted in this flow to the W Coast.
Lead, weak shortwave and responding waa regime have resulted in high
clouds overspreading Upper MI today. Temps are currently in the 30s
F across the board.
WAA regime will continue tonight as sfc trof associated with lead
wave approaches Lake Superior late tonight. Fcst soundings clearly
depict a column too dry to support any pcpn concerns from the waa.
Only possible exception could be in the ssw flow up Lake MI. With
northern Lake MI sfc water temp around 8C and 850mb temps perhaps as
low as -5C per some model guidance, there could be some light pcpn
late tonight into Sat morning. Moisture depth is shallow, so pcpn
potential is minimal. Temps in the moist layer are higher than
-10C, so pcpn, if it occurs, would be liquid and not be fzra as sfc
temps would likely be above 32F. Only schc pops were included fcst
over se Luce County. Otherwise, a LLJ of 40+ knots will translate
across the area during the night, which should result in gusty
southerly winds, especially for downsloping locations along Lake
Superior. Marquette/Alger counties should be particularly favored.
Gusts of 35-40 mph will be possible locally. Under considerable high
clouds and winds not decoupling completely anywhere, min temps won`t
fall off too much. Expect min temps ranging from the mid to upper
20s F over the interior west and central, where winds are lightest,
to the lwr 30s F east and near the Great Lakes shores.
Sfc trof will reach western Upper MI late morning/early aftn and the
e in the evening. Given the lack of column moisture, Sat will be a
dry day, except for the aforementioned schc pops over se Luce County
in the morning. Expect high temps to reach the upper 30s/lwr 40s F.
Brisk s to sw winds up Lake MI tonight into Sat morning will build
larger waves that may cause some minor lakeshore flooding/beach
erosion on the east side of the Garden Peninsula and e of
Manistique.
.LONG TERM...(Saturday night through Friday)
Issued at 529 PM EST FRI NOV 19 2021
Generally good model agreement continues through the middle of next
week. A sharp clipper system tracks southeast across the Upper Great
Lakes on Sunday with lake effect snow developing in its wake on
Monday. Surface ridging moves overhead Monday night into Tuesday
bringing an end to LES as warm air advection begins ahead of the
next approaching trough. There is reasonable agreement in a period
of more active weather Wednesday night through Thanksgiving day,
but confidence in potential impacts remains low.
Starting on Saturday night light winds and partly to mostly cloudy
skies should allow temperatures to cool reasonably efficiently. As a
result, there could be some fog potential Sunday morning, especially
near Lake MI. Attention quickly shifts to a seasonably strong cold
clipper system tracking through the region on Sunday. Polar and
subtropical jet streams are expected to be phasing as they move
overhead, but this seems to be barely too late for our CWA to see
substantial synoptic scale precipitation. The best chance for
synoptic scale precip is across the east, but boundary layer temps
near or above freezing suggest limited impacts with a rain/snow mix.
A much cooler post-frontal air mass with 850mb temperatures around
-14C moves over relatively warm Lake Superior waters around 7C
setting the stage for a moderate lake effect event late Sunday
afternoon through Monday. Post-frontal precipitation should be
primarily snow, but some rain may mix in early especially near the
lakeshores. Across the east, soundings show deep moisture and some
omega well above the inversion through Monday morning suggesting
some synoptic scale enhancement to precipitation rates. Drier mid-
levels move in as the surface low departs on Monday with lake effect
diminishing across the west half in the morning. Lake effect then
diminishes across the east Monday evening and overnight. Headlines
appear increasingly likely for a combination of falling and blowing
snow for locations favored in northwest flow.
Ridging at the surface and aloft tracks east into our area on
Tuesday with a period of southerly winds and above normal
temperatures expected leading up the the Thanksgiving holiday. A
trough and associated surface low approach Lake Superior Wednesday
evening. Ensemble guidance shows decent clustering around a surface
low track from South Dakota across Lake Superior into Ontario. While
forecaster confidence remains low, this suggests our CWA may stay on
the warm side of the surface low track. Considering it`s among the
busiest travel weeks of the year, stay tuned for updates on this
potential storm system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 534 PM EST FRI NOV 19 2021
VFR conditions will prevail thru this fcst period at IWD/CMX/SAW.
Gusty sfc winds to 20-30kt should occur at times tonight.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 443 PM EST FRI NOV 19 2021
Tightening pres gradient btwn departing high pres ridge and
approaching low pres trof will result in increasing winds across
Lake Superior tonight. Expect s to sw winds up to 30kt. May even see
some gale gusts into the nearshore and open waters of the east half
of Lake Superior late evening into the overnight. Expect winds to
diminish to 20kt or less from w to e on Sat as the weakening low
pres trof moves across Lake Superior. Winds will remain under 20kt
thru Sat night. A sharp cold front will then sweep across Lake
Superior on Sun with a low pres developing along the front e of the
lake Sun night. With the passage of the front, expect an abrupt wind
shift to nw gales of 40-45kt, continuing thru Sun night. The
strongest winds will occur over central and eastern Lake Superior.
Winds will diminish to blo gale force across the w Mon morning and
across the e by Mon evening. Passing high pres ridge late Mon
night/Tue morning will bring a short period of winds blo 20kt. With
the passage of the ridge, southerly winds will increase, likely
gusting back to around 25kt, at least across the e half of Lake
Superior, late Tue aftn into Wed.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Watch from Sunday afternoon through Monday afternoon for
LSZ264>267.
Gale Watch from Sunday afternoon through Monday morning for
LSZ162-263.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...EK
AVIATION...07
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Pendleton OR
420 PM PST Fri Nov 19 2021
updated the aviation discussion
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...Current radar and
visible satellite imagery shows the last line of showers currently
pushing through the Blue Mountains as the Lower Columbia Basin is
under mostly cloudy skies. A cold front passed through our area this
morning, and will continue to exit to our east into the early
evening hours. Some pockets of moisture will linger this evening,
but should stay very spotty and primarily at elevation over the Blue
Mountains. Skies have already begun to clear across Central Oregon
and along the east slopes of the Cascades, which will slowly extend
east overnight tonight into Saturday morning. These clear skies
tonight, coupled with a cooler airmass, will attribute to widespread
freezing temperatures as lows plummet into the mid 20 to mid 30s for
the Lower Columbia Basin. Some areas of lower elevations may stay
above freezing, for example around The Dalles and for spots along
the foothills of the Washington Blue Mountains. As damp conditions
persist and freezing temperatures are expected tonight, there is a
potential for slick roadways tonight into Saturday morning. The
higher potential for road concerns will be across our eastern and
mountain zones, primarily across the Blue Mountains and eastward.
HRRR and HREF guidance suggests that the line of showers currently
within the Blue Mountains will be the last organized rainfall we can
expect with the passing system. The HRRR is also suggesting that
upslope showers will continue to linger along the foothills and
through the Blues until 6 PM, but very little accumulations are
expected with these pockets of moisture. An upper level ridge builds
in late tonight into Saturday from the southwest on the heels of the
departing trough. This ridge will continue to build and infiltrate
into the Pacific Northwest through the day on Saturday before the
ridge axis travels through our area Sunday afternoon. This will keep
conditions dry and cold through the remainder of the short term
period. Temperatures will continue to cool through the weekend, with
Saturday`s highs in the mid to upper 40s and Sunday`s highs in the
low to mid 40s for lower elevations. Lows will also bottom-out
Saturday night into Sunday morning, as values in the upper 20s to
low 30s are expected through the Lower Columbia Basin. Snow levels
will stay consistent through the weekend, hovering diurnally between
1500-4500 feet.
There is a concern of breezy to windy conditions Sunday evening into
Monday morning for areas of the Grande Ronde Valley including Ladd
and Pyles Canyons. The departing ridge and incoming trough will
orient isobars north/south to induce strong, south winds ahead of
the incoming trough. The likely presence of a cold pool near Craig
Mountain will aid in elevated wind gusts of 20-30 mph through the
early morning hours on Monday, with likely higher gusts expected
later in the morning. 75
.LONG TERM...MONDAY THROUGH NEXT WEEK...The pattern looks to
remain active through the upcoming Thanksgiving holiday, with at
least two storm systems poised to affect the region. Between
these, brief bouts of upper ridging are apparent, with seasonably
cool and dry conditions, and perhaps brief inversions.
Ensemble and deterministic guidance reveals we will be in the midst
of a changing pattern as upper ridging is replaced by a fast moving
upper trough early in the week. Under the influence of this ridge,
and given the time of year, the potential for basin and valley fog
and stratus will exist, though it should be short lived. In the
Monday-Tuesday timeframe, ensembles reveal two possible scenarios
with an upper wave, one that is a bit deeper and farther south, and
another that is more open and fast moving. This is captured well
when assessing ensemble clusters, depicting much of the variability
is tied to the intensity and depth of the trough. A more southerly
track of the upper low would generally mean a drier and perhaps
colder situation for much of the Inland Northwest, though most
precipitation looks to be confined to the mountains. A more open
wave, as indicated by the NBM and most European ensemble members,
would bring more widespread precipitation, but it would be light
nonetheless. The main impacts with such a system would center on
some light mountain snow, generally above 3000 feet, and windy
conditions through the Grande Ronde Valley.
Ensembles are in generally good agreement with a return of upper
ridging extending from southern California north and east into the
Inland Northwest. Greater uncertainty enters into the equation by
Thanksgiving on, as fast onshore flow develops over on the northern
periphery of the ridge. There remain considerable differences among
the ensemble members in the handling of shortwave energy and bouts
of Pacific moisture moving into the region. At this time, it does
appear there will be several opportunities for precipitation from
Thanksgiving day into next weekend. Rising snow levels associated
with building upper ridging will likely keep most accumulating snow
above 4000 to 5000 feet, but we will have to monitor this closely as
we near the holiday. Regardless, the pattern look to remain primed
for more beneficial precipitation, which should continue to aid in
drought improvement.
&&
.AVIATION...A weather system persisting over the eastern third of
the region will continue to bring areas of mvfr and lcl ifr
conditions to mainly taf sites kalw...kpdt...especially in and near
showers until 06z. Otherwise vfr conditions should continue across
all taf sites through the period. 97
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 30 45 27 40 / 10 0 0 0
ALW 35 46 31 42 / 10 0 0 0
PSC 31 46 29 41 / 0 0 0 0
YKM 26 47 25 42 / 0 0 0 0
HRI 31 48 28 43 / 0 0 0 0
ELN 29 45 26 42 / 0 0 0 0
RDM 21 50 19 53 / 0 0 0 0
LGD 28 44 26 43 / 30 0 0 0
GCD 28 45 27 50 / 20 0 0 0
DLS 37 51 32 44 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
SHORT TERM...75
LONG TERM....79
AVIATION...79