Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/14/24
Area Forecast Discussion
National Weather Service Binghamton NY
1149 PM EDT Sun Oct 13 2024
.SYNOPSIS...
Showery weather will continue through Wednesday, especially
across Central New York. Dry weather will return Thursday and
will likely last through the weekend. Temperatures will also be
well below normal through Wednesday, before temperatures warm
up again late in the week.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
950 PM Update:
Increased PoPs from Binghamton north and west Monday morning and
into the early afternoon hours as a band of steady precipitation
is likely to form in this location on the NW side of a
developing low pressure system. The CAMs have come into better
agreement on this area seeing steadier precipitation, so
increased QPF amounts as well, and even went above the latest
NBM for PoPs. There still remains the possibility for wet snow
flakes to mix in over the higher elevations of the northern
Susquehanna region, Catskills and S. Tug Hill plateau on Monday;
not expecting any accumulation though with surface temperatures
and wet bulb temps above freezing.
715 PM update:
Scattered to numerous showers continue to stream over the area
this evening, with isolated thunderstorms still possible from
the Twin Tiers south across NE PA into the overnight hours.
There are also areas of fog out there which may continue
overnight. Temperatures were adjusted down 1-3 degrees with this
update. The main uncertainty in the near term forecast is how
much wrap around rain will be present on Monday, and exactly how
long will it linger. There remain differences in the CAMs such
as the 18z HRRR, 22z RAP and 18z 3km NAM. For now, took a
blended approach with this guidance for the official forecast
grids. It will become colder aloft after the surface low and
850mb low move northeast of our CWA (near Albany) by late Monday
morning or midday. As 850mb temperatures fall to around -3C in
the afternoon it is not out of the question that some wet snow
flakes begin mixing in over the higher elevations as the
precipitation shield slowly lifts northeast and exits.
Temperatures will only be in the upper 30s to mid-40s early
Monday afternoon over Central NY...with 40s to around 50 for NE
PA.
300 PM Update:
A surface low is moving through northern PA this afternoon with
a sharp temperature gradient from upper 60s in Hazleton PA to
low 50s in Scranton PA. Thunderstorms have developed along this
warm front and will move through NEPA and parts of the Southern
Tier through the evening. Most of these storms are north of the
warm front so the cells should stay elevated with some small
hail in the stronger storms. The surface low moves into the Gulf
of Maine overnight with cold NW flow behind the front as a long
wave trough digs in. Water vapor imagery shows a robust
shortwave in Northern Wisconsin this afternoon and that should
swing around the base of the trough late tonight into tomorrow
morning and provide lift for continued rain showers across the
region so chances of precipitation were kept higher through the
day tomorrow.
Across the Finger Lakes region, chances of precipitation were
raised as 850 mb temperatures fall to near -5C tomorrow with
surface temperatures of Lake Ontario up around 17C so there will
be plenty of lake induced CAPE to generate widespread rain
showers. Thunder was left out of the weather grids for now
across CNY and the Finger Lakes but there is small potential as
cold air continues to advect in with higher amounts of lake
induced CAPE develop late Monday into Monday night.
Forecast soundings across CNY showed that the freezing level
will be getting low for this time of the year, falling down to
near 2000 feet above sea level. Forecast soundings are saturated
so the wet bulb will stay above freezing for the lower
elevations but a few wet snow flakes may mix in with the
precipitation at elevations above 1000 feet for CNY Monday
night.
Frost Monday night may be tough to get as we will have wind and
clouds as well as precipitation for much of the region. Higher
elevations of the Catskills and Poconos above 2000 feet may get
below freezing thanks to the cold air advection but radiational
cooling is unlikely for lower elevations.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
310 PM Update...
An upper-level trough will sweep through the region during the mid-
week period, putting CNY and NEPA under cool, northwest flow.
Wraparound moisture and multiple passing shortwaves will enhance
lake effect precipitation. Near surface conditions will be warm
enough for just rain showers during daytime hours. Surface
temperatures will climb into the 40s and low 50s. Strong low-level
flow will be able to mix to the surface and result in blustery
conditions across the region. Conditions will feel much cooler than
what the thermometer will ready. Also, peak gusts of 20 to 25 mph
will be possible.
Cooler air will continue to filter in from the north. 850mb
temperatures will fall to -4 to -6C. These cooler conditions will be
favorable for rain/snow mix or even just snow, mainly in the higher
elevations in CNY. A trace to a couple tenths of accumulation will
be possible. Temperatures will fall into the upper 20s and 30s
overnight. Patchy frost may be possible in far southern NEPA if
skies can stay clear long enough for temperatures to quickly fall.
There is also some uncertainty if winds will be light enough for
frost to develop.
Wednesday will start out chilly, at least it will feel that way as
breezy winds will result in wind chills in the 20s and 30s as many
are heading out the door for school and work. Unfortunately, the
cool, northwest flow will remain in place despite a ridge beginning
to build into the region. As a result, temperatures only warm up
into the 40s and potentially low 50s for some in NEPA. Lake effect
precipitation will also continue with any snow transitioning
back to rain by the afternoon hours.
High pressure builds into the region Wednesday night, bringing drier
air into the region. With the trough moving out of the region, this
drier air will replace the wrap-around moisture that will be present
throughout the first half of the week. With limited moisture,
precipitation is expected to come to an end late Wednesday tonight.
Despite the cooler air starting to retreat to the northeast, good
radiational cooling will take place as skies begin to clear out,
leading to lows in the upper 20s to mid 30s. Since winds will be
calm, conditions will be favorable for frost.
For winds this period, the latest NBM guidance was lower than
previous runs and forecasts, at least through Wednesday daytime.
With a sharp pressure gradient and likely deep mixing, the previous
forecast was blended in with the latest NBM guidance. To better
collaborate with neighboring offices, NBM 10th percentile was
also used to increase the gusts. For Wednesday night, just NBM
guidance was used.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
310 PM Update...
With a ridge of high pressure in control throughout the long term
period, conditions will be mostly dry and temperatures trend warmer.
Canadian model guidance does continue to have the lake effect
precipitation lasting into Thursday as well. While that may have to
be something to consider in future updates, this update continues to
keep Thursday dry as there will be quite a bit of dry air to
overcome for this to happen. While Sunday is looking mainly dry as
well, the next system will be just outside of our region. If timing
were to trend quicker, this would then be the next chance for
showers.
Temperatures return to the 50s and 60s during this period.
Widepsread 60s are expected during the weekend. Overnight lows
won`t see as much of a warm up but 40s will be possible by
Saturday night after a week of lows in the 30s or colder. Clear
skies may allow temps to fall cooler than forecasted during the
overnight hours.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
Unsettled conditions and varying restrictions, both to ceilings
and visibility, will be in place through much of the TAF period
as an area of low pressure and trailing cold front will be
working its way through the area this evening. This low will be
followed by another low pressure system currently located over
the Upper Midwest which is expected to rotate into the region
early tomorrow morning. Scattered showers are expected to be
around most terminals this evening before there is a little bit
of a lull before the next disturbance approaches with an uptick
in showers around 08-10Z. There can be a spotty thunderstorm
this evening near and south of the low track, and a TEMPO is in
for BGM with recent lightning strikes recorded nearby. AVP will
be monitored closely with storms currently over central PA. If
they hold together, thunder will be possible between 01-03Z.
Ceilings will vary across the terminals with MVFR and worse
conditions. AVP will be VFR initially before MVFR conditions
are expected to develop at times overnight.
Winds will be increasing tomorrow morning as they shift out of
the northwest with gusts of 20-25 knots possible. Improving
ceilings are expected tomorrow afternoon and into the evening.
.Outlook...
Monday night through Wednesday...Scattered showers and
associated occasional restrictions at Central NY terminals.
Mainly VFR at KAVP.
Thursday into Friday...Mainly VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...BJG
NEAR TERM...AJG/MJM
SHORT TERM...BTL/ES
LONG TERM...BTL
AVIATION...AJG/DK
Area Forecast Discussion
National Weather Service Boston/Norton MA
1008 PM EDT Sun Oct 13 2024
.SYNOPSIS...
Low pressure tracking across the region tonight will bring more
showers into Monday morning as a cold front sweeps through, then
trending drier and breezy for Monday afternoon. Though dry
weather will prevail, blustery with below normal temperatures
are expected Tuesday and Wednesday, with a gradual warming trend
beginning Thursday into next weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
10 PM update...
One cluster of showers and isolated thunder is impacting the
Cape and Islands and will be moving offshore during the next few
hours. Meanwhile another area of convection is lifting NE from
eastern MA assocd with a weak shortwave. HRRR and NAM3k have a
pretty good handle on this and bring a round of showers and
isolated thunder into western and northern MA and NW CT around
and after midnight. Then will have to watch for yet another area
of showers and isolated thunder possibly developing across RI
and eastern MA late tonight into Mon morning as the amplifying
upper trough approaches from the west. All the guidance is
indicating area of elevated instability moving east across the
region overnight.
Overnight lows stay milder compared to last night, with low 40s
in NW MA to low-mid 50s along the coastal plain. Even milder
Cape/Islands which will remain south of the warm front with
temps upper 50s and lower 60s.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Upper-level shortwave and surface cold front move through the
region Monday morning. With dry air and PWATS tumbling to 0.5
inches, the frontal passing will clear out any remaining rain
showers. Winds behind the front become gusty from the WNW again
at 25 to 30mph. High temperatures will again be cooler in NW MA
in the low 50s, with mid to upper 60s in SE MA. Clouds begin to
clear out tomorrow morning, with mostly sunny skies by the
afternoon.
Winds Monday night continue to gust from the NW at 15 to 20 mph
as the pressure gradient remains tight due to the departing
low to over northern New England. The gusty winds will keep lows
from bottoming out in the upper 20s, instead staying in the low
to mid-30s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Much of this portion of the forecast is expected to feature a
mid level longwave trough whose axis moves from the Great
Lakes Tuesday into the Appalachians Wednesday, then moves
offshore Thursday. Beyond then, it is looking like a mid level
ridge builds over southern New England into next weekend.
At the surface, a large high pressure should move from central
Canada Tuesday, into the central USA Wednesday, before reaching
the OH valley and central Appalachians Thursday. This high
pressure should then linger nearby Friday into next weekend.
Overall, looking like a prolonged dry stretch for most of
southern New England. The exception to that looks to be mid
week, when the cold advection across our region will be
strongest. The relative difference between air and water
temperatures, which were still around 60 degrees F, may be
enough to generate some showers over the coastal waters.
Anticipating below normal temperatures just about all this week.
Thinking temperatures trend closer to normal Friday, then above
normal into next weekend.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight...Moderate confidence.
Mainly MVFR to start then IFR developing, with pockets of LIFR
for interior terminals. The Cape and Islands likely stay
VFR/MVFR overnight. Showers begin to scatter out overnight.
Winds start turning NNW overnight at 5-10 knots
Monday...Moderate confidence.
Starting IFR, but a cold front moving west to east should
quickly clear things up to VFR between 14-18z. Winds turn WNW
behind the front and gust up to 25 knots.
Monday Night...High Confidence
VFR with WNW decreasing winds.
KBOS TAF...Moderate confidence
Brief break in the showers this evening. CIGS gradually drop to
IFR before midnight. Low chance for LIFR conditions overnight
between 06z-12z. A cold front will begin to clear things out
after 12z, with VFR by 18z. Winds turn WNW with the cold front
and gust up to 25 knots.
KBDL TAF...Moderate confidence
MVFR CIGS drop to IFR after 05z. A cold front will quickly
clear things up to VFR Monday morning.
Outlook /Tuesday through Friday/...
Tuesday through Wednesday: VFR. Breezy.
Wednesday Night through Friday: VFR.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Monday Night:
A strong LLJ will bring SSW gusts of 20-30 knots for much of the
coastal waters tonight. Seas become rough starting tonight,
rising to 6-8 feet across the southern waters and 4-6 feet in
the northern waters. Scattered rain showers and possibly an
isolated thunderstorm across much of the coastal waters tonight.
A strong cold front crosses the waters late Monday afternoon,
turning winds to the WNW, with continued gusts of 20-30 knots.
Winds begin to subside to 10-20 knots Monday night, with seas
dropping to 3-5 feet.
Outlook /Tuesday through Friday/...
Tuesday: Winds less than 25 kt. Seas up to 5 ft.
Tuesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain
showers.
Wednesday: Winds less than 25 kt. Areas of seas approaching
5 ft. Slight chance of rain showers.
Wednesday Night through Thursday: Winds less than 25 kt. Slight
chance of rain showers.
Thursday Night through Friday: Winds less than 25 kt.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 2 AM Monday to 2 AM EDT Tuesday for
ANZ232>234.
Small Craft Advisory until 5 AM EDT Tuesday for ANZ235-237.
Small Craft Advisory from 2 AM Monday to 8 AM EDT Tuesday for
ANZ250.
Small Craft Advisory until 8 AM EDT Tuesday for ANZ254>256.
&&
$$
SYNOPSIS...Belk/KP
NEAR TERM...KJC/KP
SHORT TERM...KP
LONG TERM...Belk
AVIATION...Belk/KP
MARINE...Belk/KP
Area Forecast Discussion
National Weather Service Cheyenne WY
557 PM MDT Sun Oct 13 2024
.KEY MESSAGES...
- Frost and freezing temperatures are expected for many areas
tonight. Frost advisories are in effect for parts of southeast
Wyoming and western Nebraska.
- Dry weather is expected through Wednesday
- Chances for a few light showers and light mountain snow remain
possible late-week into this weekend.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 232 PM MDT Sun Oct 13 2024
Upper level ridging remains in place across the region this
afternoon, and thus the current weather pretty much reflects
what it has been for the past month. There are a few cumulus
clouds drifting off the Snowy and Sierra Madre ranges, and there
is some wildfire smoke evident streaming across from roughly
Douglas to Scottsbluff. The HRRR smoke model suggests that some
near-surface smoke may persist in small quantities into this
evening.
Tonight, the upper level ridging pattern is expected to remain
in place with a very slow moving upper level low over Nevada
drifting ever so slowly to the southeast, providing us without
impacts from it. The main story tonight will be potential for
some frost and freezing or near-freezing temperatures supported
by mostly clear skies and generally light winds. The highest
probabilities for frost are expected in far southeast Wyoming
into western Nebraska, closest to the high pressure system over
the upper midwest. For zones that have not yet seen a hard
freeze, some frost advisories were issued. I contemplated
issuing a freeze warning for Goshen county, but NBM
probabilities for temperatures actually reaching freezing are
only up to ~50% and with spatial coverage <50%. We will continue
to monitor in case an upgrade may be needed, but at this time
it`s looking like a widespread frost with perhaps localized
freezing conditions possible.
On Monday, expect more sunny and dry conditions with ridging
overhead. Winds start to become more north to northwesterly as
colder air associated with the broad high pressure to the east
retreats a bit. Expect a nice recovery in temperatures with
highs in the 70s east of the Front Range and cooler west. There
is a bit of signal for some blustery conditions at 700 hPa, so
winds have been nudged a bit above NBM for the afternoon, though
confidence isn`t high that we will see gusts much over 25 mph
except locally. Fire weather is expected to be elevated as a
result of low RH falling to 15-20% for several places, though as
a whole, wind gusts are expected to remain below 25 mph.
Potential for some more frost Monday night as some cooler air
filters back in from the east, but winds perhaps slightly more
blustery may keep temperatures a degree or two warmer compared
to tonight. Nevertheless, some frost and freezing temperatures
will again be possible.
Tuesday into Tuesday night, the closed low to our southwest will
remain there with ridging over our region. Thus, another dry and
sunny day, albeit a bit cooler with colder air moving in from
the east. There is a bit better of a signal for some gusty winds
along the temperature gradient across western Nebraska and
southeast Wyoming, though with slightly higher humidity around
20-25%. Thus, another day with perhaps some elevated fire
weather conditions, but red flag conditions are not expected at
this time. The ridging pattern starts to signal its end as the
upper level low becomes absorbed within a broader trough moving
into the western CONUS Tuesday night. Quiet and slightly warmer
weather is expected Tuesday night.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Issued at 232 PM MDT Sun Oct 13 2024
After a very prolonged period of uneventful weather regarding
precipitation, we have a highly anticipated weather pattern shift
that should bring some widespread measurable precipitation to the
region by the end of this upcoming week. Before we get there, there
will be a weak disturbance that ejects out of the Four Corners
region Wednesday. This lingering upper level low (ULL) is not
anticipated to have much energy associated with it, so the
anticipated weather forecast would just be some diurnal rain showers
and sprinkles in the higher terrain along and west of the I-25
corridor. Above average temperatures will accompany this weak
weather disturbance as we remain beneath the amplified upper level
ridging pattern, although the ridge axis will be propagating toward
the Central Plains and Great Lakes region by late Wednesday. Daytime
highs in the 70s to low 80s can be expected, with cooler
temperatures in the mountain zones. With the persistent drought
conditions being present, there will also be some breezy winds and
low RH values east of the Laramie Range. This could create some fire
weather concerns as we have very dry conditions on the flashy 1 hour
fuels.
Wednesday night and Thursday will be the onset of the weather
pattern shift. Surface pressure tendencies will fall due to lee
surface trof perturbations east of the Laramie Range and Front
Range. Surface cyclogenesis in the Dakotas will cause gusty winds in
our wind prone areas. Have bumped up the wind gusts for the gap and
wind prone areas of southeast WY to reflect this. Should model
consistency prove true, we will be close to high wind headlines for
the I-80/I-25 corridors that are favored during wind events. There
will be a surface cold front that is anticipated to slowly propagate
to the east on Thursday, bringing cooler temperatures to our north
and western forecast zones. Further east, WAA will cause daytime
high in the NE Panhandle to surge into the upper 70s to middle 80s
where the cold front won`t arrive until much later. This cool front
will not be accompanied by much atmospheric energy, so the chances
of precipitation are low for rain showers.
The main weather story is the timing of a secondary, and more potent
cold front on Friday. Model guidance continues to signal much colder
temperatures for daytime highs on Friday behind the cold front, but
there is still a high amount of spread for deterministic solutions
regarding exact timing and location of precipitation. The ECMWF,
UKMET, GFS, Canadian, and ICON deterministic models for the extended
model guidance show a longwave trough ejecting out of the Pacific
Northwest toward the Central Rockies. From there, a myriad of
localized deterministic differences emerge: heavy mountain snowfall
for the Central/South Rockies to little snowfall for our mountain
zones, and light rainfall for lower elevations. The consensus is
that the Upper Level Low (ULL) will become sheared off from the main
longwave trough and continue to "wobble" across the Four Corners
area from Friday through the weekend, bringing the highest
precipitation to areas further south and west of our cwa. Ensemble
members have a better agreement on the colder temperatures sticking
around for a short period of 36-48 hours, before we transition back
to warmer daytime highs to round out the weekend. There still
remains a lot of details to unpack with the extended model guidance,
but overall expect much cooler temperatures and measurable
precipitation to return to the area briefly by the end of the
upcoming week.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 535 PM MDT Sun Oct 13 2024
A weak upper level ridge axis will remain over the Rocky
Mountain Region and Adjacent eastern high plains through
Monday. Relatively light winds and mostly clear skies
will prevail.
HAZARDS/WEATHER TRENDS: VFR conditions will continue with
minimal Aviation concerns.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Frost Advisory from 2 AM to 8 AM MDT Monday for WYZ108-119.
NE...Frost Advisory from 2 AM to 8 AM MDT Monday for NEZ019-020-054.
&&
$$
SHORT TERM...JDS
LONG TERM...BW
AVIATION...TJT
Area Forecast Discussion
National Weather Service Grand Junction CO
548 PM MDT Sun Oct 13 2024
.KEY MESSAGES...
- One last day of near record high temperatures today.
- A system works into the region late today bringing chances for
showers off and on through Wednesday.
- A more significant system moves into the region late in the
week through the coming weekend and is expected to bring
valley rain and mountain snow as well much cooler temperatures
more reminiscent of Fall.
&&
.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 234 PM MDT Sun Oct 13 2024
Scattered showers have developed over the southern mountains
with isolated activity across portions of the central mountains
and as far north as the Bookcliffs. This is in response to
diffluent flow ahead of a weak low pressure system dropping
through the Great Basin that is pulling in some weak moisture
advection. So far, instability remains limited so no lightning
strikes are evident at this time with the HRRR indicating CAPE
around 50 J/kg or less. Some showers look to increase across
east-central Utah to west-central Colorado this evening as this
low drops further south into southwest Utah by Monday morning,
but not expecting much in the way of precipitation as chance of
wetting rain remains low with continued dry low levels. This low
does not have much dynamic support as it becomes cut off from
the main flow and trapped underneath the high pressure ridge
that will expand across the Intermountain West and Northern
Rockies, leaving this cut off low spinning over southern Utah
and near the Four Corners on Monday. We can expect weak shower
activity across the southern and central mountains on Monday
afternoon with embedded thunderstorms still possible but CAPE
still remains low. Clouds today seem to be putting a damper on
our expected high temperatures but we still remain about 10 to
15 degrees above normal today and Monday with near record highs
possible in a few areas. Overnight lows still also remain about
10 degrees above normal for mid October even though the
overnight and early morning seem to be providing some refreshing
cool relief from the afternoon heat.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 234 PM MDT Sun Oct 13 2024
Models continue to show the weakening closed low over the Four
Corners region Tuesday, before becoming an open wave and
ejecting to the northeast on Wednesday. As far as our sensible
weather is concerned, Tuesday will see gradually increasing
cloud cover and a few widely scattered showers over the higher
terrain during the afternoon and evening. Temperatures remain
similar to what we`ve seen the last several weeks. However, as
the wave begins to eject to the northeast on Wednesday, look for
more widespread cloud cover, increased shower activity over the
Divide mountains, and temperatures a few degrees cooler than
previous days. Still 5-10 degrees above normal, though.
As the Western Slope deals with a modest cooldown and mountain
showers on Wednesday, the next Pacific trough will be swinging
into the Pacific Northwest. It is this trough that looks to
finally bring a pattern shift to the Intermountain West late in
the week, with significantly cooler temperatures and potentially
much wetter conditions as well. Above normal moisture is
forecast to hang around over eastern Utah and western Colorado
through the coming weekend. On Thursday, a potent cold front
will push through, acting on that lingering moisture to bring
widespread precipitation... mainly rain, as antecedent
conditions are so warm, but some mountain snow at the highest
elevations will work in. Thanks to the front, and the widespread
showers and clouds, temperatures will drop yet again, running
now in the 4-8 degrees above normal range.
Now, in previous runs, there had been quite a bit of
uncertainty regarding the forecast for Friday into the weekend.
There had been two rather equally supported camps, one for this
trough slowing down and developing a cutoff low somewhere over
the southern Great Basin, and the other maintaining a
progressive open wave. With this morning`s 12z runs, however,
models have actually come into agreement on one solution. The
outlier guidance, the deterministic and ensemble ECMWF, have
come around to developing a cutoff low somewhere over the
southern Great Basin, putting them in alignment with the
GFS/GEFS and the Canadian model suite. This then also favors a
longer residence time of strong dynamic forcing to work on the
resident moisture, bringing a prolonged precipitation event and,
potentially, our first winter highlights of the season. Unless
something truly drastic happens over the coming days, confidence
is high that we`ll see mountain snow and valley rain Friday
into the weekend, with current forecast snow levels dropping as
low as 7K feet. The questions of exactly when, where, and how
much will have to wait a few more runs to be ironed out, as
while models have come to agree on one solution, they do not
agree on most of the details. Just a few hundred miles of
difference in the placement of the center of the low can have
drastic impacts on precipitation amounts, cloud cover, and
temperatures across the region, and guidance is still all over
the place with that factor alone. As far as temperatures are
concerned, there is a pretty strong signal that we`ll see a
substantial cooldown with this system. Ensemble guidance,
deterministic guidance, and blended guidance all drop
temperatures near to a few degrees below normal for Friday into
the weekend. That doesn`t sound that impressive until you
remember that by mid-October, the desert valleys should be
seeing highs in the low to mid 60s, and mountain towns should be
seeing 40s to low 50s for highs. That`s quite a departure from
the temperatures we`ve seen the last several weeks, and will
feel like a bit of a shock at first. But it does seem that fall
is finally making a return to the Western Slope.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 541 PM MDT Sun Oct 13 2024
More mid and high-level clouds are forecast through the TAF
period. Virga in the vicinity of TAF sites may produce periodic
wind gusts up to 25 mph. Precipitation chances increase tomorrow
afternoon over the southern mountains with a light shower or two
possible at TEX.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...MDA
LONG TERM...BGB
AVIATION...TGJT
Area Forecast Discussion
National Weather Service North Platte NE
612 PM CDT Sun Oct 13 2024
.KEY MESSAGES...
- Widespread frost and freeze event appearing likely tonight and
again tomorrow night. Potential hard freeze for most of the
Sandhills.
- Fire weather concerns return Wednesday and Thursday as
temperatures rebound, humidity lowers, and winds really strengthen.
- Fall-like temperatures come back at the week`s end, along with
precipitation chances.
&&
.SYNOPSIS...
Issued at 411 PM CDT Sun Oct 13 2024
A large upper ridge is centered over the Intermountain West, while a
trough digs across the Great Lakes, resulting in northwest flow
aloft for Nebraska. Toward the surface, a broad high pressure
extends across the central and northern Great Plains. Mostly clear
skies and a light northerly breeze complemented seasonable
temperatures in the upper 50s to 60s in the Sandhills today.
&&
.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 411 PM CDT Sun Oct 13 2024
This evening and tonight... The center of the surface high drifts
southward and will sit directly over the Sandhills after 06z. A band
of mid/high level clouds currently (as of 20z) over the Dakotas will
continue to spread south, which will probably affect far north
central Neb overnight. Other than that, mostly clear conditions will
continue, along with light to calm low level winds. All in all, the
setup appears good for full boundary layer decoupling. RAP forecast
soundings indicate a large inversion and a very dry column
throughout. Trended the min temp forecast toward the 25%ile NBM,
which falls in line with most MOS guidance, and nudged the Platte
River Valley even lower to account for cold air drainage. Would not
be surprised if some spots in the Sandhills or river valleys will be
even colder than represented. With forecast values now ranging from
the mid 20s in parts of the Sandhills to right near freezing in
southwest Nebraska, updated the Frost Advisory and Freeze Watch over
to a Freeze Warning for the entire CWA. Confidence in a hard freeze
is relatively lower for areas south of I-80, but decided upon
Warning for collaboration purposes with adjacent WFOs.
Tomorrow and tomorrow night... The upper ridge makes little eastward
progress, but the surface high continues on its trek toward the
Mississippi Valley. This pattern places western Nebraska squarely in
southerly return flow in the low levels. Later in the day, a weak
surface low then straddles the NE/SD border, which drags a trough
(warm front?) across the panhandle. Fair skies, somewhat deeper
mixing, and a period of westerly downslope flow will help push
temperatures back into the 70s for the western half of the CWA. The
warm air advection scheme kicks into high gear with 24 hr temp
changes at H85 approach 6-8C. Trended toward the warmer MAV for max
temps, partly due to the persistent dry air. Forecast values range
from mid 60s north central to mid 70s panhandle. Nighttime lows are
rather tricky this go around as an H85 thermal ridge gives way to
east/northeast low level backing flow. The sky will likely be mostly
clear again, but surface winds may stay a bit higher around 10-15
mph. Some solutions suggest "milder" lows compared to tonight, while
some solutions keep with the hard freeze criteria. For now, split
the difference, which still lines up between the 25th and 50th
percentiles of the NBM envelope, generally upper 20s to lower
30s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 411 PM CDT Sun Oct 13 2024
A secondary surface high backs into the Upper Midwest, which
continues the easterly low level flow for Nebraska, and the upper
trough digs deeper into the Eastern US for Tuesday. Guidance is in
good agreement regarding a strong cold air advection scheme with H85
temps around 10C cooler compared to Monday. Highs will likely be
stuck in the 50s for most of the CWA. Despite the east winds, no
additional moisture is advected in, as shown by falling dew points
throughout the day.
The pattern changes briefly for Wednesday and Thursday as the upper
ridge over the Rockies turns progressive and kicks across the
Plains. The surface high gets confined to the Ohio Valley while a
deep low over the northern High Plains pulls a warm front through
Nebraska, then a dryline/trough, and finally a strong cold front.
Temperatures rebound to well above normal levels (lower 80s) by
Thursday, as southerly winds really strengthen ahead of the cool
front. Gusts above 40mph are appearing more likely Wed. afternoon.
Humidity levels are marginally supportive of critical fire weather
as of now, but the wind will be more than enough to support rapid
fire spread during this timeframe. Trends will be monitored for
potential fire weather headlines.
The upper ridge promptly breaks down over the Plains at the end of
the week as a lee side surface low spins up near the CO/KS/NE border
and the front slows. This setup favors cooler conditions once again,
but also a decent chance of moisture. Discrepancies remain in the
longer range solutions regarding timing and coverage of precip, but
periodic showers Friday into Saturday seem to be a decent bet.
Capped PoP to 50% / "chance" until details become clearer. Potential
exists for some locations to receive the first wetting rain in
several weeks.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 609 PM CDT Sun Oct 13 2024
Strong sfc high pressure across srn Canada and the nrn and cntl
Plains will build south tonight and then east into the Midwest Monday.
Very dry air will remain across wrn/ncntl Nebraska during this
time and VFR is likely across the region.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 1 AM CDT /midnight MDT/ to 9 AM CDT /8 AM
MDT/ Monday for NEZ004>010-022>029-035>038-056>059-069>071-094.
&&
$$
SYNOPSIS...Snively
SHORT TERM...Snively
LONG TERM...Snively
AVIATION...CDC
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
924 PM EDT Sun Oct 13 2024
.SYNOPSIS...
As low pressure passes to our northeast, a cold front moves
through tonight into early Monday morning. High pressure will
gradually build eastward from the Midwest through mid week. This
area of high pressure settles over the Eastern Seaboard by
Thursday into next weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
EVENING UPDATE...
Some clouds and isolated showers have developed around western
Maryland and the eastern West Virginia panhandle this evening as
the cold front approaches. A few flashes of lightning have also
been noted with these cells. They have also continued further
east than earlier CAMs suggested, though the latest HRRR now caps
their eastward progression around the Blue Ridge. SPC continues
to highlight a Marginal risk for severe thunderstorms in this
area. Based on more recent CAMS, expect isolated showers with
possible thunder from now until shortly after midnight for areas
along and west of the Blue Ridge. Some weakening showers could
make it further east, but would be less likely to have lightning
and should quickly dissipate.
PREVIOUS DISCUSSION FOLLOWS...
The latest surface observations show the backdoor front has
stayed north of the Mason-Dixon Line. An expanding warm sector
is noted over the Mid-Atlantic, accompanied by increasing
southerly warm advection. With only spotty clouds and continued
surface heating, much of the area has seen temperatures rocket
well into the 70s to low 80s. In particular, a spotty area of
mid 80s can be expected across the Allegheny mountain valleys
extending from Grant County up into western Allegany County.
Southerly winds will continue to be breezy at times, pushing
into the 25 to 30 mph range at times.
Looking farther upstream, the pattern changing cold front looms
back over central Ohio. Lagging behind is the parent upper
trough which is currently spinning near the Upper Great Lakes.
Given the lack of alignment of the surface and features aloft,
the focus for convection is somewhat nebulous. The Storm
Prediction Center paints a Marginal risk for severe
thunderstorms from I-81 westward. This is actually an eastward
expansion from previous outlooks. 12Z HREF ensemble paintball
plots show some enhanced reflectivity racing from the
Alleghenies toward I-81 during the early/mid evening hours.
Locally damaging wind gusts would be the primary threat given
the higher LCLs and increasing downdraft CAPE values. Any
convective threat decays for those farther east.
The cold front currently over the Ohio Valley is expected to
cross the Allegheny Front late this evening before reaching the
Chesapeake Bay by the middle of the overnight hours. This brings
an abrupt wind shift to westerly which will become increasingly
gusty in time. Low temperatures will be coolest west of I-81
with mainly 40s expected. Farther east, 50s to low 60s are more
likely.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
The core of upper forcing with the trough pushes across the
Mid-Atlantic region early Monday. This particular surge allows
for the larger push in dew point falls as cooler/drier modified
Canadian air works its way in from the northwest. Favorable
upslope trajectories will carry a threat of rain showers along
the Alleghenies. This is accompanied by mostly cloudy skies,
gusty winds, and temperatures confined to the 40s. For
downstream locations, a considerable cool down is also evident
as high temperatures fall into the upper 50s to 60s (warmest
south of I-66). This comes with a mixed bag of sun and clouds
along with northwesterly wind gusts around 25 to 35 mph,
locally up to 40 mph across the Allegheny mountain peaks. Winds
begin to decrease in strength after nightfall with the loss of
deep vertical mixing.
Enhanced cloud cover overnight should limit the true potential
of nocturnal cooling. Low temperatures drop into the upper 30s
to mid 40s, with widespread low/mid 30s over the mountains.
There should be enough wind to thwart off a widespread frost
although the near freezing temperatures could cause a freeze in
spots across the Alleghenies.
A reinforcing shortwave continues to trend deeper for Tuesday
which has led to an uptick in precipitation chances. Not only
will this bring a reinforcing shot of cold air, it also
invigorates another round of shower activity along the Allegheny
Front. Given the cooling temperatures, some of this will
feature a mixture of rain and snow over the Allegheny ridges.
The current forecast does bring a couple tenths of an inch of
snow over such locations. It remains to be seen if this will
actually accumulate given marginal surface temperatures.
Elsewhere, scattered rain showers are advertised given the ample
ascent underneath this strong trough. These likely weaken after
dark as heating is lost. Tuesday`s high temperatures hold
steady in the mid/upper 50s, while the higher elevations can
expect 40s to low 50s. With high pressure still back over the
Mississippi Valley, it is not certain winds drop off enough to
bring a widespread frost to those from U.S. 15 westward. The
current forecast does drop lows into the mid 30s over much of
that area, with low 30s over the mountains and I-81 corridor.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The main upper trough axis will pass overhead Wednesday morning,
before moving off to our south and east later Wednesday afternoon
into Wednesday night. At the surface, a broad area of high pressure
will build eastward from the center of the country toward the Ohio
Valley by Wednesday night. Northwesterly flow ahead of the
approaching high will maintain below normal temperatures across the
area on Wednesday. Upslope snow showers will continue along the
Allegheny Front during the morning, before winding down during the
afternoon hours. Further east, a mix of clouds and sun is expected.
High temperatures will range from the 30s and lower 40s in the
mountains, to the 50s further east.
High pressure will continue to build eastward Wednesday night into
Thursday, before becoming centered overhead Thursday night. The
pressure gradient should weaken enough for many locations to
decouple Wednesday night. Radiational cooling will allow
temperatures to plummet into the 30s for most, with lower 40s in the
urban centers. Frost and freeze headlines will likely be needed for
much of the area. Sunny skies and light northerly winds are expected
during the day Thursday. High temperatures will be in the upper 50s
and lower 60s for most (upper 40s-lower 50s in the mountains).
Another night with ideal radiational cooling conditions is expected
on Thursday night as the high builds overhead. Low temperatures will
be in the 30s for most, and frost/freeze headlines will likely be
needed once again.
High pressure will remain in the vicinity through Friday and
Saturday as upper ridging builds in aloft. This will lead to
continued sunny skies, light winds, and a warming trend in
temperatures. Highs should be in the 60s on Friday (upper 50s/lower
60s mountains), and then upper 60s to lower 70s on Saturday (low-mid
60s mountains).
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
While mainly VFR conditions are anticipated through Tuesday, the
big story will be the gusty winds in response to a pronounced
pattern change. Ahead of the cold front, expect a breezy
southerly wind with gusts up to 20 to 25 knots through early
this evening. This front tracks through overnight leading to a
shift to westerly winds into the first half of Monday before
turning more northwesterly. Gusts up to 25 to 30 knots are
expected in this gusty post-frontal environment. Wind fields
largely stay out of the west to northwest into Tuesday as well.
Afternoon gusts up to 20 knots are possible on Tuesday as a
system aloft tracks through. This may also spark scattered
showers over the area, although no restrictions are expected at
this time.
VFR conditions and northwesterly winds are expected on Wednesday.
Light northerly winds and continued VFR conditions are expected on
Thursday.
&&
.MARINE...
Ahead of a strong cold front over the Ohio Valley, a breezy
southerly wind has overspread the marine waters. As such, Small
Craft Advisories are in place through tonight. This frontal
boundary pushes across the waters early Monday morning leading
to an abrupt shift to westerly winds. This gusty post-frontal
environment will yield widespread gusts of 25 to 30 knots,
potentially approaching gale force at times. However, model
soundings and high-resolution model output are somewhat at odds
at how widespread and frequent such gusts would be. For now,
will maintain Small Craft Advisories through the day which will
likely be extended into portions of Monday night.
Northwesterly wind gusts stay close to the 15 to 20 knot range
through Tuesday, slightly toward that higher range later in the
day. Small Craft Advisories may be needed over portions of the
waters during this period.
Northwesterly winds may reach low-end SCA levels on Wednesday. Light
northerly winds are expected over the waters on Thursday.
&&
.TIDES/COASTAL FLOODING...
Strengthening south winds may result in a surge into Action
Stage along sensitive shoreline later today. No coastal
flooding is explicitly forecast at this time, although guidance
is closest to minor flood stage at Annapolis. The threat ends
behind a cold front tonight.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ530>543.
&&
$$
SYNOPSIS...BRO/CAS
NEAR TERM...BRO/CAS
SHORT TERM...BRO
LONG TERM...KJP
AVIATION...BRO/KJP
MARINE...BRO/KJP
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
714 PM CDT Sun Oct 13 2024
.KEY MESSAGES...
- Sub-freezing temperatures likely tonight across central
Minnesota. Widespread sub-freezing Monday night.
- Isolated rain showers continue tomorrow across western
Wisconsin.
- Warmer temperatures to end the week, along with better chances
for rain.
&&
.DISCUSSION...
Issued at 208 PM CDT Sun Oct 13 2024
Our coldest air of the season has arrived as sprawling Canadian
high pressure spreads into the Upper Midwest. Strong cold
advection from blustery northwest winds has kept temperatures in
the low to mid 50s this afternoon, and has generated a few
isolated showers across western Wisconsin. The winds will weaken
after sunset, but speeds are still expected to remain around 5-10
mph overnight. This along with dry RH values should prevent much
frost from developing tonight despite the chilly temperatures,
but continued cold advection overnight will likely result in
temperatures dipping below freezing across west-central
Minnesota by early tomorrow morning.
Another chilly day is expected Monday as the high pressure
becomes centered over the region. Winds will be lighter, but the
cold core aloft will be centered over the area so temperatures
will again struggle to warm much into the 50s during the
afternoon. Isolated light rain showers will again develop
across western Wisconsin, and a narrow band of light rain is
also possible across southwest Minnesota as a jetstreak moves
over the eastern dakotas/western MN. Ideal radiational cooling
conditions develop Monday night as winds become calm and skies
remain clear under the center of the high pressure. Widespread
sub- freezing temperatures are expected everywhere except for
the inner core of the Twin Cities metro, and temperatures could
potentially drop all the way into the low 20s across western
Minnesota. This will be the killing frost that officially ends
the growing season area-wide, and draining un-insulated outdoor
pipes & irrigation system is a wise precaution as well.
Temperatures begin to warm midweek as southerly flow returns on
the back side of the departing high pressure, and above-normal
temperatures return late in the week as highs once again
approach the 70s. Ensembles continue to show a strong signal
for accumulating precipitation during the Friday to saturday
timeframe, as a trough over the central CONUS develops a
frontal boundary that moves through the region. The
precipitation will likely be constrained to a band along the
front, and the front looks to be in the process of decaying as
it reaches the region, so unfortunately a widespread soaking
rainfall is beginning to look less likely. Still, ensemble
guidance shows high probabilities of rainfall in excess of
0.10" which suggests it will still rain, just expect values to
likely remain below half an inch. Temperatures are expected to
cool closer to more seasonable values behind this front, with
highs in the low to mid 60s over the weekend
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 701 PM CDT Sun Oct 13 2024
Wind gusts will slowly back down over the next couple of hours.
They will increase in strength again on Monday, though at speeds
much lower than what we saw today. Mid/upper clouds will thicken
through the night in west central & southwest MN, while stratocu
in eastern MN & western WI scatters out overnight. That mid
level cloud cover will persist through much of Monday in western
MN, while eastern MN and western WI will see an uptick in
stratocu coverage as mixing commences Monday morning.
KMSP...The HRRR is showing some potential for some MVFR cigs to
be approaching MSP toward the end of the period out of WI, but
we have lots of time to see if that ends up happening.
/OUTLOOK FOR KMSP/
TUE...VFR. Wind N 5-10kts.
WED...VFR. Wind SW 10-15 kts.
THU...VFR. Wind S 15-20G25-35kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Freeze Warning from 1 AM to 9 AM CDT Monday for Benton-
Chippewa-Douglas-Kandiyohi-Lac Qui Parle-Meeker-Morrison-
Pope-Stearns-Stevens-Swift-Todd-Yellow Medicine.
WI...None.
&&
$$
DISCUSSION...ETA
AVIATION...MPG
Area Forecast Discussion
National Weather Service Reno NV
220 PM PDT Sun Oct 13 2024
.SYNOPSIS...
* Cooler temperatures continue today, before warmer afternoons
return on Monday and Tuesday.
* A storm system arrives on Wednesday bringing cooler temperatures
and shower chances to the area.
* Another system comes right behind the previous one on Thursday
and Friday, keeping the cooling trend and chances for valley
rain and possible mountain snow showers.
&&
.DISCUSSION...
The latest RAP analysis of the upper air pattern shows an upper
level low over northern NV with the REV CWA just to the west of it
being underneath the forward part of a trailing ridge. Current
satellite imagery and surface observations report mostly sunny skies
along with dry conditions across the CWA. Going forward into this
week, forecast guidance shows the low departing eastward and the
ridge residing over the CWA through Monday night. By Tuesday, the
ridge begins to progress eastward as an upper air trough moves into
the Pacific Northwest. As a result of this upper air pattern
development, dry conditions are expected to continue through Tuesday
for the region. Daytime high temperatures for today look to be in
the 60s to middle 70s range with higher elevation areas in the
Sierra topping off in the lower to middle 50s. Low temperatures
for tonight expect to range between the middle 30s and around the
50 degree mark in the valleys while Sierra Mountain communities
see temperatures drop down to between the 30 degree mark and the
lower 40s. Temperatures warm up going into the work week with
daytime highs in valley areas being in the 70s on Monday and in
the lower 70s to lower 80s range on Tuesday. Higher elevation
areas in the Sierra will see to see high temperatures on Monday in
the middle 50s to lower 60s and upper 50s to lower 60s on
Tuesday. Winds look to be generally light to start the week with
Tuesday being the breeziest day having afternoon gusts up to 20
mph possible. Fire weather does not look to be much of a concern
with these winds though Tuesday`s forecast calls for minimum
relative humidity values in the middle to upper teens in some
portions.
By Tuesday night and going into Wednesday, forecast guidance depicts
the CWA taking a southwesterly upper air flow as the aforementioned
trough moves into the northwestern CONUS. The axis of this trough
looks to pass over the CWA by the late afternoon and evening hours
of Wednesday allowing for a northwesterly flow overnight. At the
surface, a cold front looks to pass through the area bringing cooler
temperatures and precipitation chances back to the region. The best
chances (65-75%) look to be in areas closer to the OR border during
the morning and afternoon hours of Wednesday with these chances
gradually tapering off going southward though there looks to be
some chance at least for the entire area throughout the day.
Currently, QPF value look to range between a trace and around two-
tenths in northern Washoe County. At this time, the precipitation
looks to be all of a rain type though the highest elevation areas
may see some light snow mixed in (not the best confidence for
this yet). Daytime high temperatures on Wednesday drop to between
the middle 60s and lower 70s for the valley areas with the Sierra
Mountain communities seeing highs in the upper 40s to middle 50s.
The higher elevations have low temperatures at or below the
freezing point on Wednesday night while the remainder of the CWA
has lows in the middle 30s to middle 40s in the forecast.
For Thursday and Friday, ensemble guidance continues to show some
sign of an inside slider pattern. The uncertainty continues in
the latest forecast runs, so will be still be monitoring future
runs closely to see how this looks to play out. As a result,
temperatures should continue to cool on both days with yet
another cold front system passing through the region. The CWA may
see some possible enhanced winds that may cause some marine
impacts on Thursday. Chances for precipitation are again seen on
Thursday though a bit less than those on Wednesday. With cooler
temperatures, light snow may be mixed into the rain in some
locations once again with NBM guidance showing snow levels down to
around 5000 ft during Thursday night. Early snowfall totals look
to be under an inch at the mountain summits though lower
elevations could possibly also see a trace. Still a lot of
uncertainty exists, but it is worth mentioning this possible
scenario at this time. While Friday looks to be dry, it also
expects to be the coldest day of the week with high temperatures
not over the 60 degree mark and low temperatures generally around
the freezing mark. It might be a good idea to check if your
furnace needs some maintenance now in case you need to use it
later this week.
Going into next weekend, long term guidance shows an upper air ridge
moving into the area. This will allow for temperatures to warm back
up a bit as well as dry conditions to prevail. -078
&&
.AVIATION...
VFR conditions are expected to continue at all REV TAF sites with
dry conditions to begin the week. While winds will be generally
light across the CWA today, an occasional gust of around 15 kts may
be possible between 13/21Z and 14/03Z for KTRK and KMMH. Light and
variable winds are then expected to persist through the overnight
hours. -078
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$