Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/29/23
Area Forecast Discussion
National Weather Service Columbia SC
801 PM EDT Sat Oct 28 2023
.SYNOPSIS...
Strong high pressure will persist over the forecast area into this
weekend, generating above normal temperatures and dry conditions.
Expect scattered daytime clouds and light winds through Monday
before a frontal passage brings more Autumn-like temperatures back
to the region next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
High pressure centered over Georgia and South Carolina will
guarantee another quiet evening and overnight period. The persistent
subsidence over the area will allow for winds to go calm through
the first half of the night. A weak low level jet will develop
later, potentially hindering fog formation in the early morning
hours. Although the crossover temperature is fairly high the
mixing may prevent fog from becoming dense and keep it on the
patchy side. The warm start to the evening and the warm airmass
will make for another night of above-average temperatures and
upper 50s for lows.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
High pressure aloft over the Southeast U.S. will provide near record
warmth for The Midlands and CSRA Sunday through Monday. Expect highs
in the lower to mid 80s with a few upper 80s possible. Lows will be
in the mid to upper 50s.
A dramatic cooling trend starts on Tuesday with a powerful cold
front moving into the region. High temperatures will be 10 to 20
degrees cooler with the most significant changes across the upper
CSRA and western/northern Midlands. There may be sufficient moisture
for a chance of showers with the frontal passage.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A deep upper level trough moves into the Northeast U.S. during the
middle of next week and a cold front pushes off the Southeast
U.S. coast Tuesday Night. A dramatic cooling trend continues
Wednesday through Thursday with high temperatures 10 to 15
degrees below normal for early November. The first frost and/or
freeze of the fall season appears likely with lows in the upper
20s to mid 30s.
The upper level trough moves offshore by the end of next week and is
replaced by zonal flow aloft. Temperatures are expected to moderate
to near normal for early November on Friday and Saturday.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Clear skies this evening with light and variable winds. Shallow
low-level moisture across the area especially from near AGS to
OGB. With strong nocturnal cooling overnight there is potential
for early morning fog mainly at those terminals and perhaps DNL.
But models are indicating a low-level jet 10 to possibly 20 kts...so
this mixing in the boundary layer may be a limiting factor. The
HRRR and HREF suggest the higher probability of restrictions
will be focused in the coastal plain. So went with MVFR with
tempo IFR at AGS/OGB with VFR elsewhere toward 12z. Few cumulus
clouds possibly developing by 18z Sunday with southwest winds 5
to 10 knots.
EXTENDED AVIATION OUTLOOK...Chances of daily late night/early
morning VSBY/CIG restrictions. Restrictions are possible with a
cold frontal passage on Tuesday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Charleston SC
844 PM EDT Sat Oct 28 2023
.SYNOPSIS...
Dry high pressure will linger across the region into early next
week. A strong cold front will move through the region on
Tuesday into Tuesday night, ushering in substantially cooler
air into the region. Cold high pressure will then prevail for
mid to late week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
The forecast is on track. No major changes are planned for the
late evening update.
Expansive high pressure will maintain its hold on the region
tonight maintaining dry conditions across the region. Diurnal
cumulus will dissipate quickly after sunset resulting in clear
skies. As the boundary layer decouples this evening, winds will
go calm thus helping to promote strong radiational conditions.
Attention turns to the potential for fog and possibly a little
stratus development early Sunday. Dewpoint depressions will
trend towards zero after midnight as the boundary layer
saturates within a calm/light surface wind field. While these
elements are certainly supportive of fog, 1000 hPa condensation
pressure deficits are progged to remain very high with both the
RAP and H3R showing deficits of >50 hPa. This will tend to
support layers of shallow ground fog versus a single thick fog
layer. This is further reinforced by rather parched ground
conditions given the lack meaningful rainfall in about a week.
The best potential for shallow fog looks to be confined to the
coastal corridor and areas roughly south of the I-16 corridor.
Patchy to areas of fog were maintained in these areas, but
expect highly variable vsbys to occur overnight. Some locally
dense fog could still materialize, mainly near bodies of water
such as marshes, small rivers and swamps where the sfc-boundary
layer moisture field will be locally augmented.
Lows from the mid-upper 50s inland to the mid 60s at the beaches
and Downtown Charleston look on track.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Pattern Synopsis/Forecast: Highly amplified and somewhat
blocked upper flow pattern will be in place Sunday to the start
the short term, with an omega blocking ridge along the West
Coast and anomalously deep longer wave troughing through central
Canada pressing down through the central CONUS. This pattern
has delivered some fairly cold air into the northern/central
Plains behind a cold front that will be edging toward and
through the Mid Atlantic and southeast states through the first
half of the upcoming week.
Meanwhile, surface high pressure and a wedge of warm air will
remain the dominant player across the southeast region at least
through Monday. Thus dry weather and above normal daytime
temperatures are anticipated Sunday and Monday, with Monday
likely the warmest day as we develop a bit more southwesterly
flow.
Heading into Tuesday: Strong short-wave impulse is expected to
dive down through the Northern Plains and rotate through the
southern Great Lakes through Tuesday night. Operational GFS is
just a bit faster with this feature vs the Euro, although has
some support with the GEFS ensemble mean. Regardless, upshot
will be to drive the southern tail end of the robust cold front
through southeast South Carolina and southeast Georgia through
the course of Tuesday afternoon into Tuesday night. Strongest
QG-forcing for ascent will be focused well north of our
region...up through the Mid Atlantic into New England while
nearly all guidance show minimal (if any) QPF across our CWA.
That said, there may be a narrow window for a few showers to
develop along the boundary, particularly late Tuesday afternoon
through Tuesday evening, and particularly across the northern
part of the CWA where better moisture profiles will be in play.
We have been advertising some very low end rain chances across
the tri-county area during that time...which still seems
reasonable at this juncture.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Big change in temperatures midweek. In the wake of the frontal
passage, strong northerly flow develops Tuesday night and
persists through the day Wednesday. This will deliver
substantially cooler and substantially drier air into the
southeast states as H8 temps cool to a few degrees above 0C
heading into Wednesday and PWAT values dive to under one-quarter
of an inch. Other than the low chances for precip Tuesday
evening mentioned above, clearing skies take shape later Tuesday
night while temperatures dip into the 40s by Wednesday morning.
Wednesday onward: Large expanse of surface high pressure and
dry air will build/settle into the Mid Atlantic and southeast
states from mid week onward resulting in mainly sunny skies and
dry weather through the period. Given the very dry incoming
airmass and gustier northerly wind, we will need to keep an eye
on fire weather conditions during the day Wednesday. Finally,
some shower activity is possible in the coastal waters late in
the week as better moisture begins to sneak back northward,
although I think that most if not all of that activity will
remain offshore.
Frost possibilities: Forecast low temperatures will certainly
be there with inland lows in the lower to middle 30s Wednesday
night and middle 30s to near 40 Thursday night. But, a
persistent northerly flow through Wednesday night will likely
preclude much frost formation, at least more widespread frost
formation. Conditions are better Thursday night, but
temperatures will be a little "warmer." All told, no frost
mention in the forecast at this juncture, but lots of time to
tweak/adjust as we go along.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
29/00z TAF Discussion:
KCHS/KJZI/KSAV: VFR for much of the period. The risk for shallow
ground fog will increase overnight with conditions becoming
favorable for meaningful reductions in vsbys occurring at
mainly KJZI and KSAV after midnight. Conditions could drop into
IFR territory at times at both these sites before sunrise as
banks of fog meander around the aerodrome. TEMPO groups for PRFG
were used roughly 09-12z to address the possibility. Given the
synoptic pattern is not completely favorable for significant fog
development given high condensation pressure deficits and dry
ground conditions, vsbys were limited to IFR and above airfield
minimums. However, brief stints to below airfield minimums can
not be completely ruled out as banks of locally dense shallow
fog lurk about, especially since observations from both of these
sites are not manually augmented overnight. For KCHS, a brief
period of vsbys dropping to low- end MVFR could occur just
before daybreak, but no significant impacts are expected. Any
fog/stratus will quickly mix out after daybreak with a return to
VFR.
Extended Aviation Outlook: Overall VFR. Ground fog will
possible around dawn each morning through early next week. A
cold front will then cross the terminals Tuesday into Wednesday.
In the wake of the front, winds will shift northerly with gusts
between 20-25 kts on late Tuesday night through Wednesday. Some
gustiness might linger through Thursday.
&&
.MARINE...
Tonight: Seas have likely dropped below 6 ft over the Georgia
offshore leg per latest buoy trends and NWPS output. The Small
Craft Advisory for the Geogia offshore leg has been cancelled a
few hours early. Otherwise, light winds will persist over the
waters tonight with seas 2-3 ft nearshore waters and 3-5 ft over
the Georgia offshore waters.
Sunday through Monday Night: Broad high pressure across the
region will keep winds and sea below Small Craft Advisory
conditions.
Tuesday through Thursday: A strong cold front will approach the
region on Tuesday, crossing the Atlantic waters Tuesday night.
In the wake of the front, north- northwest winds will develop
gusts around 25 kts late Tuesday night through Thursday,
especially across the outer GA waters. As a result, seas are
expected to build through the period, peaking between 4-8 ft
later Wednesday through Thursday. An extended period of Small
Craft Advisories will likely be needed Tuesday night through
Thursday, primarily outside the Charleston Harbor.
&&
.TIDES/COASTAL FLOODING...
Tides will remain elevated through early next week, largely due
to increasing astronomical tides. While wind directions are not
the most favorable, departures will not need to be that high to
reach minor flooding levels, primarily with the morning high
tide cycles. Coastal Flood Advisories will likely be needed.
Charleston and Colleton county coasts could approach Moderate
flood levels, but at this time it does not appear likely.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
628 PM CDT Sat Oct 28 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Sunday night)
Issued at 208 PM CDT Sat Oct 28 2023
Convection chances for the remainder of this afternoon and into the
early evening hours remain favored along the I-35 corridor, mainly
north of San Marcos, then westward into portions of the Hill
Country. We have adjusted rain chances upward with a previous
forecast update and can`t rule out some brief, heavy downpours. WPC
maintains a small sliver of Marginal Risk (level 1 of 4) across
northern Llano and Burnet counties. There will be a chance for
showers across the remainder of the Hill Country, I-35 corridor and
coastal plains today. However, chances are a little lower in these
regions.
For tonight, rain chances remain favored for areas generally north
of a Fredericksburg to Giddings line as the leading edge of a cold
front stays near of just north of this region. We will see one more
very warm night across south central Texas with overnight lows in
the mid 60s to mid 70s. The above mentioned cold front will be
heading south on Sunday and we will favor the faster timing as noted
by the RRFS, HRRR and NAM12 models. Winds will quickly shift to the
north and temperatures will fall noticeably behind the boundary.
Daytime highs will occur early in the day for many areas as
temperatures drop behind the front. We will see a wide range of high
temperatures on Sunday ranging from the lower/mid 60s in the Hill
Country to the lower 90s along and south of the U.S. Highway 57
corridor. We do expect a gradual increase in rain chances from north
to south throughout the day on Sunday as the shallow, cold air mass
interacts with plenty of low-level moisture.
It appears rain chances will ramp up quickly Sunday night as the
cold air advection strengthens in the low-levels with warm air
advection just above this layer. Precipitable water values remain
high Sunday night and with some subtle lift moving across in the
southwest flow aloft, rain becomes widespread across south central
Texas. We can`t rule out some brief, heavy downpours that may yield
some minor flooding. Areas where soils are wet will be most prone to
any minor flooding. Given the ongoing drought situation, overall
this should be a beneficial rain event for our region. We will see
an increase in gusty north winds Sunday night and if forecast data
remains consistent, winds will likely approach Wind Advisory levels
(sustained 26-39 mph).
&&
.LONG TERM...
(Monday through Saturday)
Issued at 208 PM CDT Sat Oct 28 2023
Cold, windy conditions will be in place Monday morning with temps in
the mid to upper 30s north, low to mid 40s south. Winds of 15-25 mph
will gust to 30-35 mph in many areas and could top out above 40 mph
on an isolated basis. This will bring wind chills into the 20s in
the Hill Country! While a wind advisory could be possible in the AM,
speeds currently appear borderline. Will continue to assess.
Although winds will come down slightly through the afternoon, the
continued CAA will mean very little warm-up during the day. Highs
will remain in the 40s in most locations. In addition, scattered to
numerous showers with the highest coverage over the Hill Country and
Austin Metro could bring up to about a third of an inch of
additional rainfall during the day. Lower amounts are expected south
and west. Isolated thunder is possible with just a tiny bit of
elevated CAPE hanging around.
Monday night, isolated shower activity may linger but should push
out before sunrise Tuesday. Winds will remain somewhat elevated, and
clouds should stick around which will limit radiational cooling. We
currently don`t have any expectation of freezing temperatures for
Tuesday morning. Can`t be completely ruled out for isolated low
lying areas in the Hill Country, but the better chances will come on
Wednesday morning as clear skies return and winds die down with
surface high pressure firmly in place across much of the central and
eastern US. Freeze Warnings appear likely for portions of the Hill
Country.
High temperatures, meanwhile, will trend back upwards as the high
shifts east and southerly flow re-establishes by Wednesday night
into Thursday. Look for highs near 60 Wednesday, into the 60s
Thursday, mainly 70s Friday, and upper 70s/lower 80s Saturday. No
additional precipitation is forecast after Monday night.
&&
.AVIATION...
(00Z TAFS)
Issued at 628 PM CDT Sat Oct 28 2023
VFR flight conditions begin the TAF period with few to sct cumulus
and a few spotty light showers near KDRT. Low stratus develops late
tonight into early Sunday morning with MVFR to IFR ceilings across
the region. Rain and eventually storm chances increase on Sunday
ahead of a strong cold front quickly advancing southward into and
across the region. Added VCSH by mid-morning with some VCTS through
midday through the afternoon. The strong cold front advances past
KAUS by around noon into the early afternoon hours. The remaining
sites should see the front move across by the mid to late afternoon
hours. Winds become blustery out of the north behind the front and
will increase in speed into Sunday night. Post-frontal light rain
activity along with MVFR to IFR ceilings return during Sunday night
as well.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 72 74 40 45 / 30 60 80 70
Austin Bergstrom Intl Airport 70 75 41 46 / 30 60 80 60
New Braunfels Muni Airport 72 78 42 48 / 20 40 70 50
Burnet Muni Airport 64 67 37 44 / 40 60 90 70
Del Rio Intl Airport 73 80 43 50 / 10 30 90 30
Georgetown Muni Airport 66 69 39 44 / 40 60 90 70
Hondo Muni Airport 73 80 42 47 / 20 40 80 50
San Marcos Muni Airport 71 77 41 46 / 20 50 80 50
La Grange - Fayette Regional 73 79 43 46 / 20 40 70 60
San Antonio Intl Airport 73 79 42 47 / 20 40 80 50
Stinson Muni Airport 73 81 44 49 / 20 30 70 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...Platt
Long-Term...KCW
Aviation...Brady
Area Forecast Discussion
National Weather Service Goodland KS
755 PM MDT Sat Oct 28 2023
.UPDATE...
Issued at 742 PM MDT Sat Oct 28 2023
Winter Weather Advisory continues as wintry precipitation
continues to overspread the area. I wound up trimming ice amounts
down a bit across the area as forecast soundings indicate any warm
nose potential ending around 06-07Z as the profile falls
completely below freezing supporting more of a snow potential;
with all of that said a glaze of ice is still in the realm of
possibility across the southern Winter Weather Advisory. Recent
runs of CAMS have been hinting at a narrow band of heavier snow
from roughly Burlington through Goodland and up towards SW Rawlins
County from around 09-12Z so did nudge up snow amounts a little
bit in that corridor.
The other change I made was to continue lowering low temperatures
for Sunday night/Monday morning as a surface high nudges into the
area. This along with clearing, and some fresh snow pack would
support at least some radiational cooling to occur although a
westerly wind around 10 mph may limit overall potential
radiational cooling.
&&
.SHORT TERM...(This evening through Monday Night)
Issued at 255 PM MDT Sat Oct 28 2023
At the start of the short term period, the latest RAP analysis shows
the CWA having a southwesterly flow aloft being underneath the front
portion of a large positively tilted upper air trough whose axis is
over ID/NV/UT this afternoon. Current radar imagery and surface
observations show cloudy skies across the region with some echoes of
possible wintry precipitation starting to move into eastern CO.
Going through the rest of Saturday, forecast guidance shows the CWA
keeping its southwesterly flow through the night as the axis of the
trough moves eastward over UT/WY. At the surface, the Winter Weather
Advisory continues through the rest of the day as models show the
precipitation chances that move into eastern CO spread across the
rest of the CWA going into the night. Upon looking at model forecast
soundings across the region, there looks to be a division of P-
types continuing through the afternoon and evening with the
northwestern half seeing light snow and the southeastern half
seeing more of light mix between rain, freezing rain, sleet, and
snow. The line of division looks to progress southeast going into
the night as temperatures cool with the entire area then seeing a
P-type of snow. Current expected snowfall totals for today ranges
between a trace to around 3 inches with the higher amounts seen in
Yuma and Dundy counties. Locally higher amounts could be possible
should some banding occur and there looks to be a chance for that
around the Tri-State border just before midnight. In areas where
there may be ice accumulation, there looks to be a few hundredths
at most. Both the snow and ice may cause hazardous traveling
conditions whether it be slick roadways or reduced visibility
which is pretty much the reasoning behind the CWA-wide advisory.
Overnight lows for tonight look to range between the middle teens
and middle 20s with minimum wind chill values in the middle single
digits to lower teens.
On Sunday, models forecast the CWA`s upper air flow turning more
west-southwesterly as the day goes on as the axis of the upper air
trough progresses more eastward yet staying west of the CWA. At the
surface, models show the light snow chances continuing through the
day before ending around the evening hours. Additional snowfall
looks to range between a trace to around 2 inches in western
portions bringing the possible two day totals between a few tenths
to around 5 inches. A surface high looks to move into northeastern
CO during the evening allowing for skies to clear up overnight
leading to colder overnight temperatures. Daytime highs for Sunday
expect to be in the lower to middle 30s while overnight lows range
between the upper single digits and middle teens. Minimum wind chill
values for the night are forecast to be in the negative lower single
digits to the positive upper single digits.
For Monday, forecast guidance shows the axis of the large positively
tilted trough passing over the CWA during the late afternoon/evening
hours with a large ridge trailing it over the western CONUS. At the
surface, dry conditions and sunny skies are expected throughout the
day with a surface high projected to move south from NE across
central KS. While there may be some warming, it might not get too
much warmer depending on how much lingering snow cover there is.
Daytime highs on Monday are expected to be in the lower 40s to lower
50s followed by overnight lows in the lower teens to lower 20s
range.
.LONG TERM...(Tuesday through Saturday)
Issued at 116 PM MDT Sat Oct 28 2023
For this part of the forecast continue to expect dry conditions.
There will be a deepening upper level short wave trough over the
Missouri and Ohio River valleys, however the trough will be far
enough east to not bring any precipitation to the High Plains.
Temperatures will gradually warm through the week as an upper level
ridge moves in from the west. The warming temperatures and low dew
points will cause relative humidity values to fall into the teens
for the southwest quadrant of the forecast area Wednesday through
Friday. At this time ensemble data is favoring Friday for the
breezy winds, especially over that part of the forecast area where
the relative humidity values will be lowest.
A weak cold front is forecast to move through Saturday morning. At
this time am not expecting any precipitation with it due to the jet
stream being primarily north of the forecast area as the short wave
trough moves through.
Saturday the upper level flow becomes less certain. Models suggest
either zonal or northwest flow, just depends on how quickly the
next upper level short wave ridge approaches. &&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1140 AM MDT Sat Oct 28 2023
KGLD...MVFR conditions are seen to begin 18Z TAF period starting
with northeasterly winds around 9 kts and a broken cloud ceiling
around 2 kft. At 23Z, KGLD winds turn more northerly with vicinity
snow chances beginning before light snow is expected to begin with
cloud cover rising to 3500 ft causing VFR conditions at 01Z. By
03Z, MVFR conditions return to KGLD with the cloud deck lowering
to around 1500 ft before IFR conditions start at 07Z with
visibility forecast to lower to 2SM. The overcast cloud deck over
KGLD is expected to lower to 900 ft at 08Z and then MVFR
conditions return once again by 16Z when vicinity snow chances
begin again.
KMCK...VFR conditions look to start the 18Z TAF period beginning
with northeasterly winds around 9 kts before MVFR conditions begin
at 22Z along with vicinity snow chances when an overcast cloud
ceiling moves in at 2500 ft. By 02Z, IFR visibilities begin at
KMCK when the terminal expects to see northerly winds around 8 kts
and light snow before IFR ceilings are seen at 08Z. By 11Z, MVFR
visibilities and ceilings come to KMCK with winds backing to
north-northwesterly. At 13Z, VFR conditions start at KMCK with
vicinity snow chances returning.
Difficult forecast with timing on the snow passing through the
region along with the uncertainty seen in the model visibility and
cloud base heights. Will continue to monitor conditions and amend
TAFs as needed.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1140 AM MDT Sat Oct 28 2023
KGLD...MVFR conditions are seen to begin 18Z TAF period starting
with northeasterly winds around 9 kts and a broken cloud ceiling
around 2 kft. At 23Z, KGLD winds turn more northerly with vicinity
snow chances beginning before light snow is expected to begin with
cloud cover rising to 3500 ft causing VFR conditions at 01Z. By
03Z, MVFR conditions return to KGLD with the cloud deck lowering
to around 1500 ft before IFR conditions start at 07Z with
visibility forecast to lower to 2SM. The overcast cloud deck over
KGLD is expected to lower to 900 ft at 08Z and then MVFR
conditions return once again by 16Z when vicinity snow chances
begin again.
KMCK...VFR conditions look to start the 18Z TAF period beginning
with northeasterly winds around 9 kts before MVFR conditions begin
at 22Z along with vicinity snow chances when an overcast cloud
ceiling moves in at 2500 ft. By 02Z, IFR visibilities begin at
KMCK when the terminal expects to see northerly winds around 8 kts
and light snow before IFR ceilings are seen at 08Z. By 11Z, MVFR
visibilities and ceilings come to KMCK with winds backing to
north-northwesterly. At 13Z, VFR conditions start at KMCK with
vicinity snow chances returning.
Difficult forecast with timing on the snow passing through the
region along with the uncertainty seen in the model visibility and
cloud base heights. Will continue to monitor conditions and amend
TAFs as needed.
&&
.CLIMATE...
Issued at 255 PM MDT Sat Oct 28 2023
Record/near record low temperature possible at the following
location Monday, October 30:
Yuma.............7 degrees set back in 1991
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Winter Weather Advisory until noon MDT /1 PM CDT/ Sunday for
KSZ001>004-013>016-027>029-041-042.
CO...Winter Weather Advisory until noon MDT Sunday for COZ090>092.
NE...Winter Weather Advisory until noon MDT /1 PM CDT/ Sunday for
NEZ079>081.
&&
$$
UPDATE...Trigg
SHORT TERM...076
LONG TERM...JTL
AVIATION...Trigg
CLIMATE...DDT/MRC
Area Forecast Discussion
National Weather Service Green Bay WI
1008 PM CDT Sat Oct 28 2023
Updated aviation portion for 06Z TAF issuance
.UPDATE...
Issued at 725 PM CDT Sat Oct 28 2023
Saturation has occurred with a narrow band of frontogenetic
forcing from Wood county to Stevens Point, Shawano, and central
Door County. Light snow or mixed rain/snow has been reported west
of Shawano. Models suggest that this frontogenetic band will shift
east and weaken later this evening, followed by a short lull, then
perhaps some redevelopment over the SE half of the CWA late
tonight into Sunday morning. Have adjusted pops to match these
trends. Could see local accumulations of a dusting to half inch
on grassy surfaces west of the Fox Valley, but don`t anticipate
any significant travel concerns.
&&
.SHORT TERM...Tonight and Sunday
Issued at 228 PM CDT Sat Oct 28 2023
Key Messages:
- The chance of light rain/snow has increased to 30% to 50% over
central to northeast WI from late this afternoon through
tonight. Little to no snow accumulation is expected.
- Partial sunshine is expected on Sunday, but high temps will
remain about 10 degrees below normal.
Forecast Details:
While a surface ridge axis will continue to extend across the
western Great Lakes through Sunday, southwest flow will remain
aloft ahead of persistent troughing positioned over the northern
Plains. The right rear quad of a jet streak combined with
convergent mid-level flow will lead to a fgen band lifting
northeast across central to northeast WI tonight. Precip chances
have increased slightly (30-50% chance) and have narrowed precip
chances somewhat compared to the previous forecast based on latest
CAM runs.
Guidance in general shows the mid-level convergence band
weakening tonight as it moves across the region, and precip rates
will not be sufficient to allow for accumulations given the warm
ground temps. Perhaps a light dusting will be possible on grassy
surfaces over central WI.
A gradual clearing trend is expected from northwest to southeast
on Sunday, though how quickly skies clear are relatively
uncertain. Both the HRRR and RAP keep the low stratus in place
into Sunday morning, which could delay clearing from the current
forecast. Will generally stick with continuity for now.
Temperatures: Low level temps would argue for steady temperatures
running about 10 degrees below normal for Sunday`s high temps.
Warmed low temps tonight due to cloud cover compared to the
previous forecast.
.LONG TERM...Sunday Night Through Saturday
Issued at 228 PM CDT Sat Oct 28 2023
A strong upper-level low-pressure trough will push down out of
Canada into our area on Tuesday morning. The trough will move
through relatively quickly, generating only moderately strong
surface cyclogenesis. However, the system will begin to tap Gulf
of Mexico moisture as it moves into the Great Lakes and has
potential to deliver an inch or two of snow accumulation in some
portions of northeast WIs. Temperatures will certainly be cold
enough for snowfall across all of central and northeast Wisconsin
at night. Low temperatures will be in the teens and 20s from
Monday night through Friday morning.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 959 PM CDT Sat Oct 28 2023
The main frontogenetic band of precipitation weakened mid-evening,
and has not redeveloped since. Models suggest a general lull in
precipitation chances until later tonight/early Sunday, when a
brief period of light snow may impact the eastern TAF sites.
There is a small chance of MVFR conditions with the light snow
early Sunday, but most of the region should see VFR conditions
through the TAF period. Clearing should occur from NW to SE late
Sunday afternoon and evening. Light to moderate NW-W winds in the
5-10 knot range are anticipated through the period.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.........Kieckbusch
SHORT TERM.....MPC
LONG TERM......ML
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Indianapolis IN
938 PM EDT Sat Oct 28 2023
.Forecast Update...
Issued at 938 PM EDT Sat Oct 28 2023
- Rain will continue to overspread central Indiana this Evening
National radar mosaic was showing high coverage of rain across
central Indiana this evening. The rain was mostly in the form of
light returns with a few 40+ DBZ echoes mixed in. The rain was
moving in to the Metro and also southeastern sections and should be
over all or most of central Indiana within the next hour or so. The
rain was associated with ongoing 305K Isentropic lift and
disturbances in the southwest flow aloft. Potent northern Ontario
jet (170+ knot jet max) places central Indiana in the right read
quadrant which along with PWATs increasing to over 1.5 inches will
allow for some enhanced rainfall at times. Look for most areas to
see over a half an inch rainfall by morning and some areas could see
an inch or more. There have been a couple of lightning strikes
nearby, just south and north of central Indiana. So, would not
completely rule out a stray lightning bolt or two the remainder of
the evening, otherwise light to moderate rain with pockets of heavy
rain will continue through the night with rain decreasing over the
Wabash Valley toward daybreak.
&&
.Short Term...(This evening through Sunday)
Issued at 300 PM EDT Sat Oct 28 2023
- Rain Tonight and Sunday
- Cool
Surface analysis early this afternoon shows a cold front stretching
from Western PA to East Central KY and then southwest to western TN.
Large and cool high pressure was found over the western northern
plains states, spilling into the upper midwest and Indiana in the
wake of the cold front. Aloft water vapor shows the upper flow,
consisting of a strong area of high pressure over the Gulf States
and a broad low over Hudson Bay. This was resulting in warm
southwest flow aloft across much of the United States. GOES16 shows
extensive cloud cover across Central Indiana, with two features in
play, the high clouds streaming across the southern parts of the
forecast area and lower clouds invading from the north amid the weak
cold air advection.
Tonight -
Active weather is expected tonight. The models suggest the quick
upper flow aloft will become a driving force for precipitation. A
300mb jet streak near 130 knts is expected to push across WI and
Michigan tonight, placing Indiana in a favorable position for lift
on the right rear of the jet. Moisture streaming northward from
this feature can be seen across OK/Arkansas, pushing northeast
within the quick flow aloft. Forecast soundings across the area
trend toward a saturated column overnight as this forcing and
moisture arrive. PWATS trend toward 1.35 inches, which is quite high
for this time of year. HRRR shows the showers to the southwest
arriving in the area near 00Z and increasing in coverage as the
night progresses. Thus confidence for rain is high tonight given the
above. Best coverage should be found beneath the upper plume of
moisture, across the southern parts of the forecast area. Thus will
include highest pops there but only slightly lesser pops across the
north. No matter where you are tonight in Central Indiana,
confidence for rain is high. Given the expected clouds and rain,
lows in the upper 40s to around 50 will be expected.
Sunday -
The upper pattern is little changed on Sunday. The strong pressure
gradient aloft due to the deep low over the Hudson Bay and High
pressure over the gulf states will remain in place. This allows for
continued efficient transport of upper level moisture from the
southwest along with continued favorable lift across Indiana in the
right rear of the jet streak in place across the Great Lakes. After
some morning subsidence within the upper levels, forecast soundings
suggest deep saturation returns by mid to late afternoon with PWATs
now near 1.15 inches. At that time, favorable forcing again appears
in place aloft. Thus will continue to forecast rain on Sunday, with
best chances during the afternoon. Again, given the expected clouds
and rain, steady state temperatures around 50 will be expected.
&&
.Long Term...(Sunday night through Saturday)
Issued at 314 PM EDT Sat Oct 28 2023
* Additional Light/Moderate Rainfall Sunday Night Thru Early Monday
* Near-Record Cold Monday-Wednesday Night...with Three Hard Freezes
* Halloween Windy, Unseasonably Chilly, Few Flurries Possible
The long term will begin with round two of this weekends rainfall...
include several days of unseasonable chill and near-record cold
mornings...and end with milder breezes bringing moderation to near
normal through the late week.
Sunday Night through early Monday...
Sunday night will find the region amid the northwestern/back side of
an elongated and somewhat broad moist ribbon extending from the
southern Plains to the Northeast...between rather weak surface low
pressure over the Mid-Atlantic and strong, broad high pressure
plunging through the central CONUS. The region will be just far
enough south/east to catch the ribbon`s corresponding anafrontal
overrunning rain, which will arrive from the southwest through the
evening before departing rather quickly to the east through Monday`s
AM hours. Zones south of the I-70 corridor will likely see greatest
rainfall yet again per longer duration under steadier rains.
Potential for any locally heavier bands is less than with the short
term`s first round of rain as better deep moisture will have quietly
departed to just southeast of the region. Nevertheless precipitable
water values as high as 1.25 inches Sunday evening along the US-50
corridor may promote additional 15-hour rainfall through Monday
morning up to 1.00 inch...while the solid majority of the CWA picks
up another 0.25-0.75 inches of welcomed rainfall. While the
aforementioned colder blast will begin entering Indiana early
Monday, high confidence in precipitation ending as rain with
readings near 40F.
Late Monday through Saturday...
Unseasonably cold and mainly dry conditions will then build into
central Indiana on Monday as broad, amplified Canadian high pressure
that will have plunged into the southern Plains then builds east. A
dry column and westerly breezes that should prevent too much
moisture from becoming trapped in the low levels should promote
mostly clear skies...with diminishing winds Monday night under
negative 5 Celsius H850 temps bringing a hard freeze to all zones.
The most blustery conditions of next week`s cold blast should
accompany a potent short wave bringing a reinforcing shot of
Canadian high pressure, arriving during PM hours Tuesday. Clouds,
and most notably breezy to briefly windy conditions are expected,
with west-northwesterly gusts to 20-35 mph impacting the region at
prime trick-or-treating time...producing wind chills around 20F in
the early evening. Flurries/snow shower potential also exists late
Tuesday, but the moisture starved column, fast-paced nature of the
supporting vort, and antecedent temperatures near/above 40F would
not support any impacts. Any snow would be most likely north/east
of Indianapolis where the combination of the passing wave`s
proximity and lake-enhanced flow would most likely combine.
Cold overnights will continue Tuesday night and Wednesday night as
the broad surface ridge oozes eastward while occupying most of the
lower 48. Widespread mid-20s expected, and the CWA`s notorious
colder spots perhaps dropping to near 20F. Rather breezy conditions
should continue during daylight hours...courtesy of the decent
gradient aloft from the upper polar low`s shift equatorward into
Hudson Bay. However, this will also facilitate moderating
southwesterly return flow through the late workweek...with reading
returning to seasonable levels by the Friday-Saturday timeframe.
The overall broad upper zonal trough pattern across much of the
CONUS should continue mainly dry conditions through the late long-
term, with guidance noting the next, rather weak short wave progged
to bring a few light showers around the Saturday timeframe...while
colder air remains retracted farther north into interior Canada.
&&
.Aviation...(00Z TAF Issuance)
Issued at 649 PM EDT Sat Oct 28 2023
Impacts:
- Rain will reach KHUF around issuance time and the other
TAF sites by 00z-02z
- MVFR ceilings will deteriorate to IFR and worse at times in
showers by around 05z Sunday
- The rain will become more spotty toward 12z but more rain is
expected by Sunday afternoon
Discussion:
Warm moist air streaming in from the southwest combined with
impulses in the southwest flow aloft, will bring widespread rain and
deteriorating ceilings tonight. After a brief break, more rain will
return Sunday afternoon.
Winds will be northeast and north less than 10 knots.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...MK
Short Term...Puma
Long Term...AGM
Aviation...MK
Area Forecast Discussion
National Weather Service North Platte NE
641 PM CDT Sat Oct 28 2023
.SYNOPSIS...
Issued at 213 PM CDT Sat Oct 28 2023
Key Messages:
- Accumulating snow continues through Sunday morning with total
accumulations of 2 to 4 inches with locally higher amounts
expected along and south of the I-80 corridor. Winter driving
conditions are expected, use caution while driving.
- Dry and cold conditions will persist through early next week
with a reinforcing shot of cold air arriving just in time for
Halloween festivities on Tuesday.
- Mild temperatures return by the end of the week with continued
dry and quiet conditions.
Recent GOES-16 WV and RAP 500-mb analysis showed a shortwave trough
diving southward into the central Rockies. Further southeast of this
feature, upper-level high pressure was anchored over Florida. At the
surface, strong high pressure continues to encompass Montana into
the northern Plains. Downstream of the shortwave, a strong 250-mb
jet streak was evident from the Plains to the Great Lakes region.
Divergence under the left exit region of a strong 250-mb jet streak
is parallel to a band of increased mid-level frontogenetical
forcing. In response, light to moderate snow showers have developed
with a narrow band of heavy snow continuing to move north and east
into north central Nebraska. Area road cameras via 511 shows
winter weather driving conditions with decent snow accumulations
on roadways and visibilities as low as 3/4 of a mile, especially
for areas along and east of Highway 83. Continued snowfall for
areas along and east of Highway 83 will result in additional
accumulations of 1 to 3 inches through this evening. Make sure to
use caution if you are traveling today.
&&
.UPDATE...
Issued at 623 PM CDT Sat Oct 28 2023
The third and final snow band is setting up across swrn Nebraska
this evening. This one will be weaker than the earlier band and 1
to 3 inches of snow is predicted across swrn and scntl Nebraska this
evening and overnight.
The Winter Weather Advisory can be cancelled north and west of a
line from Tryon to Thedford and Ainsworth where NDOT indicates dry
pavement and this risk of additional snowfall is low.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 213 PM CDT Sat Oct 28 2023
The expectation is that the ongoing band of snowfall will continue
to shift further north and east out of the forecast area with a
brief lull in precipitation this evening. However, frontogenetical
forcing will quickly increase again in response to the large scale
synoptic forcing. The second band of snow is expected to develop
further south of the first band across northeast Colorado into areas
south of I-80 in southwest Nebraska around sunset. Anticipate
that the second band of snow will consist of a light snow showers
with a more narrow band of moderate to heavy snowfall, similar to
what occurred earlier this afternoon. With this second band, total
snow accumulations of 1 to 3 inches is expected with locally higher
amounts possible. Though only flurries are anticipated for areas
west of Highway 83 and north of I-80, temperatures quickly falling
into the teens overnight will lead to an increased concern for
refreeze on wet roadways. Continue to use caution on roadways as
winter driving conditions are expected to persist through Sunday
morning.
As the 250-mb jet streak shifts further east and the mid-level
shortwave ejects east out of the Rockies early Sunday, expect
snowfall to gradually taper off through Sunday morning across
southwest Nebraska. Subsidence behind the departing system will
result in clearing skies through the day. Daytime temperatures
will continue to remain 20 to 25 degrees below normal in the 30s
across western and north central Nebraska.
.LONG TERM...(Monday through Saturday)
Issued at 213 PM CDT Sat Oct 28 2023
The upper-level pattern for the start of the long term period will
be defined by continued troughing across the bulk of the CONUS with
a potent shortwave dropping southward out of Manitoba into the Upper
Midwest on Monday. As the shortwave continues towards the Great
Lakes region, a strong arctic cold front will be tracking
southward across the area late Monday night. A brief period of
strong northerly winds will develop in response to the passage of
the frontal boundary overnight Monday with gusts of 25 to 35 mph
before gradually diminishing Tuesday morning. These gusty winds
combined with cold overnight lows in the 10 to 15 degF range will
result in sub-zero and single digit wind chill values early
Tuesday morning. High temperatures Tuesday will remain cold in the
30s to near 40 degrees under clear skies, though with continued
breezy winds, wind chill values will struggle to get out of the
20 degree range through the day. These spine chilling temperatures
will begin to fall into the 20s with wind chills in the teens for
trick or treat time Halloween evening. If participating in
Halloween festivities, make sure to bundle up to keep yourself and
the little ones safe from these cold conditions.
Fortunately, the cold doesn`t stick around for long as upper-
level ridging nudges further northward into the western CONUS on
Wednesday. The mean flow aloft will flatten some on Friday with
northwest flow persisting across Nebraska. As a result,
temperatures will moderate into the at or slightly above normal
range, generally in the 50s and 60s for the latter end of the
week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 641 PM CDT Sat Oct 28 2023
Snow will develop across southwest Nebraska this evening bringing
accumulating snow of 1 to 3 inches to the area. Reductions in
visibility down to 1 mile at times are also possible leading to
additional aviation concerns. Snow continues into early Sunday
morning before pushing off to the southeast. Elsewhere across
Nebraska, cloudy conditions are expected with ceilings below 5000
feet through Sunday morning. Strong northwest winds across northern
Nebraska during Sunday afternoon may result in some lingering
aviation concerns before diminishing after sunset Sunday night.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 7 AM CDT Sunday for NEZ010-026>029-
037-038.
Winter Weather Advisory until 10 AM CDT /9 AM MDT/ Sunday for
NEZ056>059-069>071.
&&
$$
UPDATE...CDC
SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...Kulik