Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/11/23
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
531 PM CST Tue Jan 10 2023
(Now through Wednesday night)
Issued at 128 PM CST Tue Jan 10 2023
Warmer than normal temperatures continue the next few days with
another bout of fog possible tonight. Southerly winds get a little
gusty Wednesday ahead of a cold front nearing the county warning
area (CWA) late Wednesday night.
Temperatures have steadily climbed today with widespread lower 80s
as of 2:30PM CST. This despite some fog around the area for a few
hours early this morning. These warm temperatures are due to an H5
ridge building overhead behind yesterday`s shortwave. This ridge has
really dried us out, as evident by the very dry air on the water
vapor loop from GOES-16 and the very low humidity above 600mb on
this morning`s sounding from KBRO. The H5 ridge remains overhead
tonight and much of Wednesday before breaking down a bit Wednesday
evening in response to a shortwave moving through the middle of the
country. This shortwave will be responsible for developing an area
of low pressure in Oklahoma. Winds increase Wednesday afternoon as
the pressure gradient tightens ahead of a cold front. A Wind
Advisory isn`t expected at this time due to the lack of a strong low-
level jet overhead. Still, gusts between 30 to 35 mph are expected,
especially along the coastal counties, during the day Wednesday.
Fog will be a concern again tonight thanks to ample surface moisture
in place and the expectation of a relatively clear sky. The biggest
question tonight will be how long the winds can stay on the calmer
side. If the wind remains too elevated, the formation of fog would
be incredibly tough with only a low stratus deck likely. It should
be noted that the HREF and SREF continue to advertise probabilities
of 50 to 60 percent for visibility of less than one mile across the
Brooks/Kenedy Ranches, Brush Country, and Rio Grande Plains. On the
flip side, the HRRR shows visibility staying at or above 6 miles
tonight. As a result, will hold off on any Dense Fog Advisory, but
one may be needed later tonight depending on how the wind behaves.
As for temperatures, have leaned a little on the warmer side of
guidance for high temperatures as we`ve been running a bit too cool
during the day. Interestingly, we`ve been running a tick too warm at
night, so have leaned a little more on the cooler side of guidance
for overnight lows. Even then, well above normal temperatures will
continue the next couple of days with upper 50s to middle 60s
expected tonight and again Wednesday night. Widespread middle 80s
are in the forecast Wednesday with an outside chance at a few
locations outside of the Lower RGV making a run at 90!
(Thursday through next Tuesday)
Issued at 128 PM CST Tue Jan 10 2023
Wind will be the main weather-maker, at least periodically,
through the long-term. Model guidance continues to trend a bit
cooler for Friday, so we may actually see one day with below-
normal maximum temperatures. By the way, by early next week,
climatological averages start to tick upward, ever so slightly,
from their annual minimums which are reached at the tail-end of
December. Another significant warm-up appears increasingly likely
by MLK Day and the following Tuesday, with blended guidance
showing mid-80s for much of the CWA, which is right in line with
the Climate Prediction Center`s latest 6-10 Day Outlook. Rain
chances will be hard to come by, with GFS time-height sections for
Brownsville remaining rather dry at mid-levels.
That being said, have added a mention of "sprinkles" for Thursday,
in association with a cold front, for areas east of I-69E in
Cameron and Willacy counties. This is consistent with
deterministic model (very light) QPF and WPC guidance. As
mentioned in previous discussions, this front is not expected to
blast through the area, but will be more of an "oozer". 12Z NAM
has it slowly sagging through the CWA, from NW to SE, from about
09-18Z Thu, and model consensus is close to this. With N-NNW flow
aloft ahead of ridging over the Desert Southwest, the front will
usher in a somewhat cooler and much drier airmass. Per the NBM
4.1, dewpoints fall into the 20s and 30s F (except along the
immediate coast) by Friday afternoon as the surface high settles
in. This may lead to some fire weather concerns on Thursday; see
Went a little below the NBM for temps Thu night/Friday/Fri night,
leaning more toward the NBM 25th/50th percentile values from the
probabilistic guidance, which seemed more in line with raw model
temps in the mid-60s for Friday daytime. Both nights should
feature lows in the 40s, with Saturday morning a bit colder. Going
with mid-upper 60s for highs on Friday, as modest cold advection
continues, working against clear skies and a dry atmosphere.
Ridge axis aloft passes on Saturday, with low-level onshore flow
returning by later in the day, allowing temperatures to rise back
toward normal. Sunday looks windy, with the GFS quickly tracking a
shortwave trough from the Four Corners region toward the
Panhandles, leading to surface pressure falls in the Plains. MEX
guidance pointing toward a Wind Advisory for the Lower RGV;
however, ECMWF is farther north with the shortwave energy. Have
kept the blended wind guidance for now, which suggests windy
conditions but perhaps not Wind Advisory levels.
Weak zonal flow sets up overhead by Martin Luther King, Jr. day
(16 Jan), with the aforementioned temps warming up. Next upper
trough moves into the Rockies the following day, possibly
bringing back breezy conditions. Both GFS and ECMWF hint at
another weak frontal passage around the middle of next week.
Issued at 512 PM CST Tue Jan 10 2023
VFR conditions prevail now with moderate southeast winds and
clear skies. Low clouds lie over the cooler nearshore waters.
Broad high pressure will remain in control tonight and Wednesday.
Model guidance is picking up on an IFR/MVFR fog/low ceiling
signal near dawn on Wednesday. Winds will decrease to light
tonight but may remain strong enough to preclude denser fog at
the TAF sites. Any low clouds would likely come from over the
adjacent cooler waters. Thus, a few hours of degraded aviation
conditions can not be ruled out during the morning hours of
Wednesday. Confidence was not high enough to go with strongly
limited TAFs, but will monitor trends this evening for updates by
the next TAF set.
.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE 64 83 67 76 / 0 0 0 10
HARLINGEN 63 84 65 78 / 0 0 0 10
MCALLEN 64 87 65 79 / 0 0 0 10
RIO GRANDE CITY 60 91 61 80 / 0 0 0 0
SOUTH PADRE ISLAND 66 77 66 70 / 0 0 0 10
BAYVIEW/PORT ISABEL 64 82 65 75 / 0 0 0 10
Area Forecast Discussion
National Weather Service Cheyenne WY
539 PM MST Tue Jan 10 2023
Issued at 530 PM MST Tue Jan 10 2023
Winds have been declining over the last hour or two. Mesoanalysis
shows pressure gradients across the Laramie range on the decline
also. GOES water vapor satellite imagery indicates that the strong
subsidence that ended up just west I-25 this afternoon has also
weakened. Therefore, have decided to expire all of the High Wind
Warnings on time. A few gusts of 55+ MPH will remain possible for
the next three hours or so primarily in WY Zone 117 (South
Laramie Range foothills) and near Bordeaux, but could see this
extending to parts of I-25 south of Wheatland. Local
height/pressure gradients are expected to become negative by
.SHORT TERM...(This evening through Wednesday Night)
Issued at 226 PM MST Tue Jan 10 2023
The main concern with this portion of the forecast is when the
winds speeds will diminish and snow band potential in Converse and
Niobrara counties tonight and early Wednesday morning.
Latest water vapor loop was showing strong subsidence over the
Laramie Range this afternoon where wind gusts have reached 70 mph.
The subsidence has been struggling to push east of the I-25
corridor, but most locations west of the I-25 corridor have
reached high wind warning criteria this afternoon. The 750-650mb
jet streak will continue to shift east into the Nebraska panhandle during
the remainder of the afternoon and early evening. However, there
will be limited subsidence in this region and minimal mixing.
We are still planning on letting the high wind warning expire at
5pm, but the latest HRRR is showing high winds peaking at Cheyenne
around 4pm. Later shifts will need to keep an eye on the cloud
cover and subsidence fields to see if this can transpire. After
this jet streak moves through, things should begin to settle down
after sunset, but those underneath the cloud cover may keep winds
mixing for a while in southeast Wyoming.
After midnight, the HREF and GFS ensembles including the Global
models are advertising a snow band developing over Converse and
Niobrara counties late tonight mainly towards 09Z and persisting
through at least 15z. This band of snow appears to be associated
with good diffluence aloft ahead a shortwave moving through the
Intermountain west. There also appears to be an elevated boundary
aloft between 700-600mb moving through that region which will
undergo some frontogenesis. Not confident on the intensity of
this band, due to limited instability of aloft. However, later
shifts will need to keep an eye on this in later runs, because the
short range models have been trending upwards with snow amounts.
As a result, we went ahead and issued a Winter Weather Advisory in
the lower elevations of Converse and all of Niobrara counties.
The next question will be how far southeast this band of snow
transverses late tomorrow morning into the early afternoon. If the
bands of snow are intense enough, it may warrant an advisory for
portions of the northern Nebraska panhandle. For now, we will see
how this initial band evolves. Meanwhile, those locations around
Cheyenne and Kimball may get robbed from the bulk of the snow due
to the potential for downslope flow. Still looks like some heavy
duty snowfall in the mountains.
Wednesday night most of the precipitation should move out of the
area as high pressure settles in east of the Laramie Range in
response to the upper level ridge moving into the area.
.LONG TERM...(Thursday through Tuesday)
Issued at 226 PM MST Tue Jan 10 2023
A relatively dry, warm, and breezy long term forecast period as a
strong ridge develops and remains stationary over the forecast area
until Sunday. Saturday we begin to see a pattern change with a brief
shortwave pushing through followed by a stronger shortwave. Global
models have trended further south, leaving southeast Wyoming and the
Nebraska panhandle not in the most favorable spot for rain/snow
chances. While the mountains will likely see a few inches of snow
due to the upslope flow and increased moisture, the chances decrease
for valleys and lower elevations. As the initial shortwave moves
through Saturday afternoon, the GFS is showing westerly winds 40 to
50 knots at 700 mb. So, the chance for High Winds is present,
therefore trended the winds and wind gusts upward late Friday night
through early Sunday morning. The rain/snow chances increase going
into Sunday with the second, stronger shortwave trough pushing
through. As this is still 5-7 days out, there is plenty of time for
the models to shift and change.
Temperatures will remain on the warmer side with highs in the 30s to
40s Thursday, increasing in the High Plains to 50s Friday and
Saturday. Sunday, as the shortwaves push through and the wind shifts
to north-northwesterly, allowing colder air to advect into the area,
high afternoon temperatures will drop back to 30s and 40s with the
coldest temperatures out west.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 443 PM MST Tue Jan 10 2023
Western Nebraska Terminals: VFR conditions expected during the
evening hours with some mid-level clouds. Late tonight/early
tomorrow morning CIGs will begin to drop ahead of a storm system.
Some light snow is possible during the early morning hours, with
periods of moderate to heavy snow and IFR conditions likely by mid
to late morning.
Southeast Wyoming Terminals: After a windy day, expect winds to ease
this evening. Later tonight, clouds will increase across all
terminals with lowering CIGs. KRWL will see snow showers develop
overnight, with KLAR and KCYS following with snow by the early to
mid morning. Expect IFR conditions in falling snow.
Issued at 226 PM MST Tue Jan 10 2023
Fire weather concerns will be minimal due to widespread snowfall
and higher humidity during the next couple of days. However, more
elevated fire weather conditions are possible along the I-80
corridor between Cheyenne and Kimball Friday and Saturday due to
lower humidities and gusty winds.
WY...Winter Weather Advisory from 11 PM this evening to 11 AM MST
Wednesday for WYZ101-102.
Winter Storm Warning until 11 PM MST Wednesday for WYZ112.
Winter Weather Advisory until 11 PM MST Wednesday for WYZ114.
Area Forecast Discussion
National Weather Service Des Moines IA
519 PM CST Tue Jan 10 2023
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Tuesday/
Issued at 308 PM CST Tue Jan 10 2023
-Fog across the north Tonight into Tomorrow
-Light snow/freezing rain chances north Tonight
-Light snow/rain south on Wednesday night into Thursday morning
Fog and low stratus has once again developed over northern Iowa this
morning, this time still hanging around by early afternoon. However,
the fog has finally started to slow its southward plunge and
visibilities have slightly improved for some. Unfortunately, there
doesn`t appear to be much sign of this going anywhere overnight.
Depending on which model you look at, fog and/or low clouds could
improve tomorrow morning, or, if you believe the HRRR, could last
through Wednesday and into Thursday. As always, it`s tough to say
exactly when this fog will disperse, but a subtle increase in winds
tomorrow afternoon should help the chances of improvement.
Aside from the fog and stratus through the next few days, we also
look ahead to a couple of days with lower-end precipitation
chances, one to the northern portion of the state tonight and the
other to the south on Wednesday night and Thursday morning.
Moisture will be the key variable with these two systems as both
struggle to find enough moisture to overcome the drier air.
As mentioned, the first of these systems will move through tonight,
mainly impacting southern Minnesota and Wisconsin. However, those
along the Iowa/Minnesota border will also be clipped by this system,
resulting in light snow and freezing rain potential within this
area. However, this is far from a sure thing due to a stout dry
layer just above the surface. This dry layer will make it difficult
for any hydrometeors developed higher in the column to reach the
surface. However, moisture depth near the surface has slightly
increased in depth through the day, increasing the chances for some
light freezing drizzle across the north. Regardless, this still
remains borderline with both NAM and HRRR soundings being under 1km
of saturation above the surface.
Should any hydrometeors make it through the low-level dry layer,
or should moisture depth over-achieve guidance at the surface, it
would not take much to make surfaces slick. Therefore, in
collaboration with neighbors, have decided to continue some light
PoP chances in the far north. Confidence is low on the southern
extent of this, so kept chances north of Highway 20 for now, but
will continue to monitor this as models have begun to indicate
slightly better chances further south into the state.
The second of these two systems will move through late Wednesday
night and into Thursday, this time impacting the southern part of
the state. The track of this precipitation has wavered some over
the last few days, and there has been a good deal of uncertainty
amongst long range and short range guidance on the exact location
of precipitation. Right now, the most likely location resides
across southern and southeastern Iowa, especially given recent
short range models zeroing in on this area. The other area of
uncertainty resides within the precipitation type. Given current
soundings, it appears a warm nose aloft could lead to a brief
period of freezing rain as the column saturates. However, cool air
quickly takes over, switching precipitation over to snow. In
collaboration with neighbors, decided to keep this system as rain
and snow for now, but expecting the need for some freezing rain
mention should this warm nose become more prominent in future
On the back side of this system, temperatures will cool off a bit on
Thursday and Friday, but won`t stay that way long as they warm
through the weekend. Similarly, winds will ramp up as the system
departs resulting in gusty conditions on Thursday. Looking ahead to
next week, long range models show multiple precipitation producers,
one towards the beginning of the week and another by mid week
bringing more rain and snow chances to the area. &&
.AVIATION.../For the 18Z TAFS through 18Z Wednesday afternoon/
Issued at 1137 AM CST Tue Jan 10 2023
Fog and stratus have remained persistent across the north today, as
KMCW continues to see LIFR conditions. Similar conditions are
expected shortly at KALO. Confidence is relatively low in how much
improvement will be seen at either of these sites through the day,
but would expect some improved visibilities this afternoon before
falling again in the evening. KALO is in a more difficult spot, as
it looks to be on the edge of expected fog and stratus through today
and into tomorrow morning. Therefore, KALO may see occasional
improvement as they sit right along the edge, but are expected to be
dealing with some form of fog and stratus through tomorrow morning
as well. KFOD would be next in line as this fog/stratus pushes
south, but is less certain to experience this fog and will continue
to monitor for changes. Some low clouds are expected to move in
towards the end of the TAF period tomorrow at KFOD. KDSM and KOTM
will be VFR through the period.
.AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/
Issued at 516 PM CST Tue Jan 10 2023
Significant categorical restrictions from fog/stratus across
northern Iowa is the primary terminal forecast challenge through
the next 24 hours. LIFR to IFR conditions are already in place at
KMCW and KALO. Recent trends and model guidance suggest little
potential for improvement this evening into the overnight hours.
The main question is how far south the sub-VFR conditions creep
tonight. Maintained mention of VFR conditions at KDSM due to low
confidence in the occurrence of low stratus and fog this far
south, but will need to be closely monitored and may be considered
for future TAF issuances should trends move in that direction.
Area Forecast Discussion
National Weather Service Quad Cities IA IL
529 PM CST Tue Jan 10 2023
Issued at 235 PM CST Tue Jan 10 2023
Other than some cirrus across the cwa skies were sunny. Mid
afternoon temperatures were in the mid 30s north to mid 40s south.
.SHORT TERM...(This evening through Wednesday)
Issued at 235 PM CST Tue Jan 10 2023
Forecast message: Dry with above normal temperatures.
Tonight: Upper level trough moving into the central Rockies will
allow for warm air advection to kick in. Forecast soundings
indicate the mid levels in the column moistening up, but the low
levels are quite dry. However, at ground level the temperature/dew
point spread is close so there is the potential for patchy fog
developing later this evening and overnight. Low confidence on
dense fog but nonetheless with temps at or below freezing a few
slick spots are possible. Lows will range from the mid 20s along
Hwy 20 to the lower 30s south.
Wednesday: Partly sunny with any lingering fog burning off by late
morning. Forecast soundings indicate the low levels still quite
dry so no pcpn expected during the day. By late afternoon, a
digging trough moves into the central/southern Plains with low
pressure along the Kansas/Oklahoma border south of Medicine Lodge,
Kansas. Highs will range from the lower to mid 40s north to near
50 in far northeast Missouri.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 235 PM CST Tue Jan 10 2023
1) Chance for light rain and snow late Wednesday night into Thursday
2) Highs mainly in the 40s Sunday into Tuesday with a chance for
rain Monday into Tuesday
Wednesday Night through Thursday, a low pressure system in Arkansas
will be moving NE up the OH River valley region. Latest GFS and now
Euro has shifted slightly southeast with the track which brings
mainly deformation precip across the southern third or so of the
CWA. This system appears to be rather quick-moving and focused for
after midnight Wednesday night until about midday Thursday.
Wednesday evening may be entirely dry with only some lingering
precip in the eastern CWA Thursday afternoon. The bulk of the precip
may be confined to a rather narrow band, and where this exactly sets
up is unknown at this time. As for ptypes, it appears to be mainly
rain mixing with and changing to snow as it moves across the area.
QPF amounts have come in lower and range from a hundredth or two
along Fairfield to the QCA to Sterling, with around a tenth inch
from Memphis MO to Princeton IL. Snow amounts will mainly be under a
half inch. While impacts will be limited, it appears that a
rain/snow mix will be ongoing during the Thursday morning commute,
especially south and east which may have some travel impacts.
Thursday, temperatures will be much colder with highs in the 30s and
blustery NW winds making it feel even colder.
Thursday night through Sunday, dry conditions will prevail as high
pressure moves across the region. Friday will be cold with brisk NW
winds and AM wind chills in the single digits and teens. Highs will
get in the mid 20s to lower 30s, with wind chills only rebounding
into the teens to low 20s. A nice warmup is expected over the
weekend and early next week as southerly flow behind the high brings
40s back into the area.
Monday into Tuesday, models are actually in pretty good agreement in
bringing a low pressure system across the region. The current blend
has mainly rain for this event with likely POPs focused on the
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 517 PM CST Tue Jan 10 2023
Ground fog will remain possible in the next 24 hours, but with
high cloud cover expected to continue, there is low confidence on
the timing of any fog onset. The HRRR suggests winds will remain
very light, and fog waits until tomorrow in the middle of the day
to onset. That is a odd time of day, for what should be another
mild day in the 40s. For now, I have kept conditions VFR, but will
watch trends to see if we need more hours of fog potential.
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
558 PM CST Tue Jan 10 2023
.DISCUSSION...(This evening through Tuesday)
Issued at 439 PM CST Tue Jan 10 2023
-- Key Messages for the entire 7-day forecast (see end of
discussion for shorter term forecast details):
* This 7-day forecast features MAINLY dry/quiet weather with two
quick-hitting systems that could bring at least minor amounts
of precipitation: 1) one mainly late Wed afternoon- overnight
that bears watching just in case it "over-produces" on snowfall
(especially in our south)...2) another one Sunday evening-
Monday that very preliminary looks like it could be mainly
* Temperatures over the next 7 days as a whole look to continue
the above normal/average trend (mid-Jan avg. highs range mid 30s
to low 40s), with most areas well into the 30s/40s on most days
and more 50s likely this weekend, especially in our southern
coverage area (CWA). Even our overall-coldest day (Thurs) still
has highs no worse than low-mid 30s.
* Other than a period of modesty-windy conditions Wed evening-
Thurs AM (gusts up to around 35 MPH likely), the remainder of
the 7-day looks to be fairly "calm" by winter standards, with
even gusts on most days no more than 25 MPH.
* Peeking JUST BEYOND our official 7-day, there are hints of
perhaps another system to watch around next Wed (Jan. 18), but
obviously this is fraught with uncertainty at that time range.
-- More detailed overview/highlights of the entire 7-day forecast
(including ALL discussion of Days 3-7 Fri-Tues):
1) General overview of the large scale upper air/surface pattern
and any notable model differences):
At least through Day 6 (Monday), the latest ECMWF/GFS remain in
pretty remarkable agreement on the large scale upper air pattern.
In short, we first see "system #1" affect parts of our CWA
tomorrow evening-overnight as it passes mainly slightly to our
south. In its wake, we reside under northwesterly flow Thursday
before a large-scale ridge gradually transitions into/over the
Central Plains Fri-Sat (ushering in a nice warm-up). While Sunday
daytime should remain dry/mild, already Sun night-Mon the next
quick-moving shortwave trough zips through our region in some
semblance (exact track still uncertain) followed by another
period of weak ridging/quasi-zonal (west-east) flow Tues. As is
typical, the GFS is suggesting a faster arrival of yet another
possible system by Tues afternoon/evening, but our official
forecast keeps Tues dry (more in line with ECMWF) with the next
possible weather- maker holding off until Wed. At the surface,
GFS/ECMWF are also in good agreement. As mentioned, other than a
period of northerly gusts 30-35 MPH Wed night-Thurs AM associated
with system #1, winds should not be a very big deal during the
vast majority of the 7-day. The overall-strongest SOUTHERLY winds
are likely Saturday, but at least for now gusts are only progged
around 25 MPH.
2) Precipitation overview:
As mentioned, we have 2 distinct windows of opportunity for at
least minor precipitation in the 7-day: 1) one mainly late Wed
afternoon-overnight that bears watching just in case it "over-
produces" on snowfall (especially in our south)...2) another one
Sunday evening-Monday AM that very preliminary looks like it could
be mainly liquid/rain (but plenty of uncertainty at that time
range). Will cover the shorter term system in more detail below in
the "Short Term Detail" paragraphs, so skip ahead for that if
interested. As for the second system, all small chances (PoPs) are
currently confined to the Sunday evening-Monday daytime time
frame. Although plenty of details are yet to be resolved for this
one, early indications suggest the mid level low could track
similar to slightly farther north than the shorter term one, with
warmer temperatures aloft tending to keep precipitation as more
rain than snow, along with a non-zero chance for a little freezing
rain/ice. However, because this system is still well out in the
Day 5-6 range, have kept any mention of freezing rain/ice out of
our official forecast for now.
3) Temperature overview:
As touched on in the opening bullets, our overall above-normal
temperature regime just keeps marching on. While we are not
talking seasonably-balmy 60s or anything, we are also not talking
frigid highs in the single digits (or worse) or sub-zero wind
chills. Just a steady dose of days mainly in the 30s/40s and some
50s likely over the weekend (especially KS zones). As for
overnight lows, most every night should bottom out in the
teens/20s most places...again slightly above normal overall and
certainly nothing out of line for January. Peeking ahead beyond
our 7-day forecast into Week 2 (Jan. 18-24), the latest ECMWF
ensemble continues to depict an overall slightly above normal
regime, with highs mainly 30s in our north/40s south.
-- With the main messages/highlights of the entire 7-day outlined
above, will conclude with shorter term details focused solely on
the next 48 hours/4 forecast periods...with a particular emphasis
on the Wed afternoon-overnight system:
- Current/recent weather scene as of 345 PM:
Despite more high level clouds streaming overhead today, it has
again been seasonably-mild by January standards, Although the
clouds have kept our KS zones from achieving the upper 50s, snow-
free areas of our southern/eastern CWA have managed to reach the
low-mid 50s with cooler highs somewhere in the 40s most common
over lingering shallow snow cover in our northwest 1/3 or so.
Winds today have been seasonably-light, generally averaging around
10 MPH (some slightly higher gusts) from mainly a southerly
direction. In the mid-upper levels, short term model data and
water vapor satellite imagery confirm broad, quasi-zonal flow over
the Central Plains, with our main upstream feature of interest
being a shortwave trough currently over southern CA/NV, residing
in the southern periphery of a large-scale trough and associated
closed low churning off the Pacific Northwest coast.
- This evening-overnight:
High confidence in continued dry conditions. While the night will
start and likely end with a fair amount of continued mid-high
level cloud cover, much of the overnight should actually clear out
pretty efficiently in between "pushes" of the higher clouds. At
the surface, breezes overnight will remain fairly light (only
around 10 MPH or less), but direction will gradually turn westerly
and eventually northwesterly behind a weak trough axis. While some
light haze is certainly possible mainly over areas with continued
snow melt in our far north/west-central, the predominant westerly
breeze should keep legitimate fog at bay and have kept out of the
forecast. These light breezes should also keep temps from
"tanking" too far (despite a period of clearing skies) and have
low temps aimed no lower then 24-28 most areas (perhaps a bit
colder in our typical colder spots such as Ord).
- Wednesday daytime (through 6 PM):
The majority of the day (especially pre-3 PM) carries high
confidence in remaining dry, although clouds will thicken/lower
with time in the mid-high levels, and we will likely see lower
cloud development by late afternoon. In the mid-upper levels, the
main shortwave trough will start the morning over CO, but by
sunset will have reached the central/southern KS, strengthening as
it does so with a closed low developing at 500 millibars. Through
sunset, the vast majority of the CWA probably stays dry, but have
low PoPs (mainly 20-30 percent) in most areas mainly 3-6 PM as
the leading edges of light-rain-changing to snow could get
underway in our far west, with more spotty light rain showers
perhaps developing farther east within mainly the southern half of
our CWA. Do not anticipate any possible wintry precip travel
issues pre-6 PM at this point. Temp-wise, it will be a good 5-10
degrees cooler than today thanks to thicker clouds and weak cold
air advection behind a cold front. Nudged highs up slightly south
and down slightly north, yielding a range from mid 30s far north
to around 40 central (Tri Cities) to upper 40s south (mainly KS).
Winds will gradually increase out of the north as the day wears
on, averaging sustained 10-20 MPH/gusts around 25 MPH by late
- Wednesday evening-overnight (after 6 PM):
For sure, the 6 PM-4 AM time frame is currently our #1 concern of
the entire forecast package. In the basics of the mid-upper
levels, the closed low that starts the evening over central KS
will steadily depart/track eastward into central MO by sunrise
Thurs. As has been the case for several forecast cycles, the main
low will slide slightly to our south, but perhaps NOT QUITE as far
south as it appeared a few days ago. This means that precip
chances especially near/south of the KS line have increased now
versus previous forecasts, with even some "likely" 60+ percent
introduced with this forecast. Meanwhile, much lower PoPs only 20
percent tops reside in our far north (with middle areas including
Tri Cities remaining a bit of a middle ground/question mark).
Without going into TOO MUCH detail for the 3rd forecast period,
here are some high points:
- our official forecast did not change much with regard to snow
totals, calling for evening-overnight accumulations of generally
one-half inch or less for most of our Nebraska zones (especially
south of I-80), and with amounts closer to 1" in our KS zones.
- This falls pretty well in line with most larger scale models
such as NAM/GFS/ECMWF. However, am a bit concerned by last few
HRRR runs, which are more aggressive in developing a more
concentrated deformation/mesoscale band from around the Tri
Cities and south-southeastward. Should this materialize, cannot
rule at at least snowfall exceeding expectations, with a quick
2-3" of slushy, wet accumulation not out of the question.
Unfortunately, confidence is still too low at this time range to
accurately place such potential for these higher amounts.
- Expect a pretty quick transition from rain to snow, but a BRIEF
period of freezing rain probably cannot be ruled out (especially
in our southeast zones). However, have kept this out of the
official forecast, Hazardous Weather Outlook etc.
- Despite the west/slushy nature of the snow, some visibility
reductions could easily occur for up to a few hours in any
steadier bands as northerly wind gusts increase to 30-35 MPH.
- No matter how little (or locally how much?) snow falls, even the
more aggressive models are in good agreement that the back
(north) edge of the snow band should depart our far southeastern
CWA by around 4 AM or so.
- In summary: there is a non-zero chance that this event could
still "over achieve" and even prompt a shorter-notice Winter
Weather Advisory, but at least for now the minimal snow amounts
do not justify one.
Low temps Wed night aimed low 20s north to mid 20s south...can`t
go any colder given steady winds/plentiful lingering clouds.
- Thursday daytime:
This will almost surely be the overall-coldest day of the next
week. Although any lingering snow/flurries should be long gone by
sunrise, especially the morning will probably feature quite a bit
of lingering lower clouds, with in theory more sunshine breaking
out in the afternoon (not a sure thing). Winds will remain
somewhat blustery in the morning (gusts 20-30 MPH) but will
gradually ease in the afternoon as a surface high pressure axis
slowly eases in from the north. High temps aimed from low-mid 30s
in most of our Nebraska zones, to as warm as the upper 30s-low 40s
in our KS zones and Furnas County area, but should a fresh coating
of snow be on the ground from Wed night then these values could be
a bit optimistic.
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 538 PM CST Tue Jan 10 2023
VFR conditions should continue throughout the TAF valid period. We
do expect a weak storm system to move into the region late
Wednesday afternoon, but more likely just beyond the end of the
TAF valid period Wednesday evening. Although a few flurries or
sprinkles can not be ruled out Wednesday afternoon, the better
chance for perhaps light snowfall accumulation will be Wednesday
evening just beyond the 24 hour TAF valid period.
The wind will be light through Wednesday morning, generally out of
the west this evening and then northerly by Wednesday morning.
North winds will increase Wednesday afternoon gusting 20 to 25 mph
by late afternoon.
Clouds bases should remain above 5000 ft agl throughout the
period, but will likely fall quickly just beyond the end of the
TAF valid period Wednesday evening.
Area Forecast Discussion
National Weather Service Green Bay WI
619 PM CST Tue Jan 10 2023
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 237 PM CST Tue Jan 10 2023
The latest RAP analysis and satellite/radar imagery show a trough
of low pressure extending northwest to southeast across Wisconsin
early this afternoon. Other than the Fox Valley and Lakeshore,
visibilities haven`t improved much so far today. Areas across
central WI have seen visibilities below 1 mile consistently, and
some locations have been steady in the 1/2 to 1/4 mile range. The
surface obs may have a low bias, however, as area webcams show
only patchy dense fog across that area. Have considered a dense
fog advisory, but considering the patchy nature as shown by
webcams, have decided to highlight the threat in a SPS. Ice
accumulation sensors are also ticking off light ice accretions,
which could also indicate freezing drizzle at times. Looking
upstream, a shortwave trough is moving across the Dakotas and
poised to enter the area late tonight. Forecast concerns include
dense fog potential and potential for a light wintry mix.
Tonight...The weak low level trough of low pressure will gradually
lift north across the state. If visibilities do not improve much
this afternoon, it`s quite possible that areas across central to
north-central, and parts of far northeast Wisconsin will need a
dense fog advisory. Some icing is possible on untreated roads and
surfaces as temps fall below freezing, particularly over far
northeast WI where light upslope flow will continue at least
through the evening. Then attention turns to precip chances as
disjointed shortwave energy moves into the region from the west.
Higher resolution models have shifted a narrow band of light
precip in the warm advection zone further south and target parts
of central WI and the Fox Valley late tonight. Forecast soundings
indicate concerns about deep saturation with ample mid-level dry
present. If precip does develop, enough warm air may surge north
to introduce wintry mix of sleet and freezing rain in with snow.
Slippery roads could develop if this were to occur. Temps will
remain relatively steady and range from the mid 20s to low 30s.
Wednesday...Weak warm advection will cause any light precipitation
to lift north across the region. Thermal profiles would continue
to suggest a light wintry mix is possible across central and
east-central WI before surface temps rise above freezing. Precip
accums have gradually diminished over the past several runs and
now only provide up to a half inch of snow, highest across far
northern WI. Uncertainty regards placement and amounts of the
precip band is too high to issue any headlines. But will mention
scattered slippery spots on roads are possible in the HWO. Highs
will be ranging through the 30s.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 237 PM CST Tue Jan 10 2023
Main highlights for the long term will be a brief bout with lake
effect snow Thursday night over the north, a quiet weekend, then
watching a system for early next week that looks to bring a
wintry mix. Temps will remain above through the period.
Wednesday night into Thursday night...continued cyclonic flow,
weak shortwave energy along with an approaching stronger
shortwave will keep skies cloudy, with small chances for some
light precip, especially over north central WI. As colder air
advects into the area, delta Ts will climb into the teens over
Lake Superior. With a favorable N/NNW fetch, lake effect snow
showers and flurries are expected Thursday afternoon into Thursday
night. Amounts look to be on the light side, with up to an inch
or two in the favored locations in Vilas Co. Little to no
accumulation is expected elsewhere. North winds will increase on
Thursday as the low pressure system to our south/east strengthens.
Gusts of 20-30 mph are likely inland, with higher gusts closer to
Lake Michigan. Temps won`t drop much Wednesday night due to the
clouds, with most spots seeing lows in the mid 20s to low 30s.
Another day with a small diurnal range on Thursday, with highs
only climbing into the upper 20s and 30s. A push of colder air,
along with some possible partial clearing, will bring colder temps
Thursday night, with lows in the teens and 20s.
Rest of the long term...any lingering lake effect snow will wrap
up Friday morning as drier air works into the western Great Lakes.
Will be challenging to get rid of the lower clouds initially, but
partial clearing is expected for parts of the area especially by
Friday afternoon. However, a mid-upper cloud deck will be
increasing across the area which will limit the amount of sunshine
we see. High pressure slides over the region on Friday then east
of the area this weekend. This will set up a slow but steady push
of WAA. While it looks like we will lose the low clouds for a
time, the mid-upper clouds look to be present for much of the late
week and weekend. Temps will moderate into the weekend, with
above normal temps prevailing. Some spots could climb to/above 40
degrees Sunday into Monday. Friday night is still looking like the
coldest with the best chance for some clearing and the cold air
still in place. The quiet weather will come to an end on Monday as
storm system gathers strength in the Plains and heads into the
Great Lakes Monday night into Tuesday. The system will not have a
lot of cold air to work with, but just enough cold air on the
north/west side to bring some precip type issues into the
forecast. Models vary on track of the low and therefore
temps/precip types. Will continue to monitor trends as the system
gets closer, but this will be the next more significant weather
maker for the area.
.AVIATION...for 00Z TAF Issuance
Issued at 617 PM CST Tue Jan 10 2023
Low clouds, fog, and light precipitation will be the primary
aviation weather concerns this evening. Anticipate little change
in ceilings or vsbys during the evening. Scattered light
precipitation is likely across the north--mainly in the form of
DZ/FZDZ based on surface temperatures.
Area Forecast Discussion
National Weather Service Grand Rapids MI
943 PM EST Tue Jan 10 2023
Issued at 939 PM EST Tue Jan 10 2023
Going forecast is on track.
Skies have cleared over the southwest cwa but high clouds continue
a steady march toward the state. Expect mostly cloudy overnight.
Visibilities have fallen to around 5 miles in the clearing area
which is also were we saw some rain/snow today. I don`t expect
vsbys to fall too much farther given the clouds moving in.
Latest HRRR continues to show a very brief period of light rain
Wednesday morning but freezing rain remaining west of the cwa.
.DISCUSSION...(This evening through next Tuesday)
Issued at 213 PM EST Tue Jan 10 2023
- Risk for Fog Tonight
We will add patchy fog to the forecast for tonight. Satellite
trends show the clouds trying to thin out over the region.
Forecast models show a potential for a period of scattered cloud
cover this evening. Already the visibilities are slightly
restricted in places. South to southeast zones saw measurable
precipitation today...which will keep the moisture high near the
ground level there. As we scatter out with the cloud cover in
those regions and we develop some radiational cooling...it looks
like at least patchy fog could form. The latest HRRR shows the
eastern zones developing fog tonight with visibilities under a
mile. Surface temperatures will end up near freezing so if fog
does form...we will need to monitor the potential for icy spots on
- Potential for light rain/drizzle Wednesday
Shallow warm and moist air advection arrives Wednesday as a
shortwave moves in from the west. Good saturation in the low
levels is noted with some lift. This may allow for light
rain/drizzle to form. At this time surface temperatures look like
they will be just above freezing when the potential for
precipitation will be on the increase. Thus we will feature only
- Low Risk for impactful snow Thursday into Thursday evening
The models are in decent agreement with the low track for Thursday
into Thursday evening...tracking it northeastward through OH. We
will be in a favorable location for snow to accumulate. However
the thermal profiles are initially warm and this system does not
have very cold air to work with. Thus how much we cool off
Thursday is somewhat uncertain...especially since the temperature
fall will be partly driven by the precipitation intensity.
However forecast soundings show enough cooling to support a period
of snow on the backside of the departing storm with Thursday
afternoon/evening being the most likely window for this to happen.
Ground temperatures are likely to be relatively warm...so melting
on roads and sidewalks looks likely to happen. This will lead to
slushy accumulations where the band of steadiest snow falls. At
this time...the Lansing to Jackson region is shown to be in the
most favorable location for accumulations as that is the region in
our CWA shown to see the strongest mid level FGEN. If this system
is able to tap slightly colder air...then the impacts would
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 645 PM EST Tue Jan 10 2023
IR loop shows clearing over southwest Lower trying to move east.
We should see some progress with this south of I-96 tonight.
However, that`s also an area that saw a little bit more rain/snow
today. So, if skies clear, then we`ll likely see some fog develop,
especially at AZO/BTL/JXN.
Expect MVFR conditions overnight, either due to cigs or fog
restricting visibilities. Toward morning, weak low pressure will
approach and short range models are hinting at the potential for a
brief period of light rain. Don`t think it will amount to much and
covered it with a VCSH comment.
Issued at 213 PM EST Tue Jan 10 2023
The wave of low pressure that tracks eastward through the region
Thursday into Friday will generate some higher winds and waves.
The highest waves are forecast on the backside of the system due
to the deeper mixing that occurs with cold air advection. A small
craft advisory will likely be needed then. Otherwise a relatively
weak pressure gradient regime is forecast to prevail.
Area Forecast Discussion
National Weather Service Indianapolis IN
915 PM EST Tue Jan 10 2023
Issued at 915 PM EST Tue Jan 10 2023
No significant changes required to going forecast.
Mid and high cloud will continue to steadily increase overnight
ahead of our next low pressure system, which will bring drizzle, low
clouds, and a few showers to the area on Wednesday.
Min temp forecast is in good agreement with latest guidance, as the
increasing cloud cover along with increasing warm advection will
limit diurnal cooling, and mid 30s to around 40 is a good target for
Latest high res guidance is indicating some potential for drizzle a
little earlier than what is in grids, but this would be of minimal
consequence if it occurred with no threat of freezing, so going
forecast has it covered adequately.
.Short Term...(This evening through Thursday) Issued at 306 PM
EST Tue Jan 10 2023
Rest of Today
Generally clear skies are found across Indiana this afternoon within
broad subsidence on the backside of a departing shortwave. The trend
will be reversed, however, as a weak shortwave quickly approaches
from the west. High cirrus clouds are expected to begin increasing
in coverage later this afternoon and into tonight. Cirrus should
remain thin enough for a sharp inversion to develop shortly after
sunset this evening.
Low-level moist warm advection should commence overnight as winds
turn southerly. Aloft, a more southwesterly component to the wind
will allow warm but dry air to build in above 850mb. BUFKIT
soundings show a nearly saturated layer below 850mb after 12Z, with
a pronounced mid-level inversion and dry layer - an ideal drizzle
sounding. As such, drizzle will be included in the forecast after
Wednesday and Wednesday Night
Model soundings remain relatively the same through the day Wednesday
with a pronounced low level inversion and dry mid-levels. Two
inversions actually are present within the soundings, one in the
near-surface layer and another centered at around 850mb. There
exists some divergence within the model soundings at this point.
Higher resolution models tend to retain the near-surface inversion
while the GFS, for instance, erodes it fairly quickly allowing
temperatures to rebound to about 50 degrees. The solutions with the
strong, more long-lived inversion keep surface temperatures as much
as 5C cooler. Will lean towards the stronger inversion scenario
given the light surface winds, strong low-level WAA above 925mb, and
dry air aloft. Will keep high temps a bit below guidance given
the idea of more persistent low stratus, drizzle, and light winds.
By Wednesday night, an upper-level trough and associated surface
cyclone will approach the Ohio River Valley. Favorable jet dynamics,
isentropic lift, and an increasingly saturated column will lead to
widespread rain developing late Wednesday night.
As the center of the surface low swings through, a brief period of
instability may develop within the system`s warm sector. The
greatest chance of this occurring appears to be mainly across our far
southern counties and down towards the Ohio River, given the likely
track of the surface low through the Indianapolis area. Guidance
generally shows weak CAPE, but a few hi-res models such as the RAP
give upwards of 800 J/kg with a more wrapped up low. Guidance shows
plenty of shear exists with robust flow aloft, near 50kts through 0-
6km. The environment will also be characterized by lapse rates just
slightly steeper than moist adiabatic. Severe weather is not
currently anticipated, however, as most models show the near-surface
inversion persisting into Thursday as well, albeit not as strong.
South towards the Ohio River, outside of our forecast area, the
inversion has the best chance of eroding away. In response, the SPC
has included areas just south of our CWA within a Marginal Risk for
severe storms. Given the parameters mentioned above, storms within
the risk area to our south have a low threat for small hail and
marginally severe wind gusts.
.Long Term...(Thursday night through Tuesday) Issued at 306 PM
EST Tue Jan 10 2023
The long term period will start out Thursday night with a system
slowly making its way out of the area. With the cold front having
made it`s way through the area during the day Thursday, temperatures
overnight will drop into the 20s as that colder air advects in from
the N and NW. Moisture will remain in the area on the backside of
the low, so there is a good chance of rain transitioning to snow
Thursday night into early Friday with light accumulations possible.
One uncertainty will be when precipitation ends with this system and
the speed at which the surface low exits the region. While the
surface low will push off to the NE, a secondary upper low will form
and track ESE towards the mid-Atlantic states. This will allow upper
ridging and a surface high to settle in over the Ohio Valley through
the weekend. The precipitation could continue into the day Friday
with that backside moisture, especially if the surface low slows
down. Parts of central Indiana could even see scattered snow in the
afternoon with a potential for some Lake Effect precip under the
northerly flow, but confidence remains low at this time. For now
have chance PoPs through Thursday night with only slight chance of
PoPs Friday. All precipitation chances will confidently be gone by
late in the day Friday as subsidence and dry air with the high
pressure strengthening. Otherwise, dry weather and near normal
temperatures in the upper 30s will persist for much of Friday and
As the high progresses eastward, southerly flow will return to the
region and temperatures will quickly return to the 40s and 0s for
the start of the new week. Another system will move through early to
mid next work week, so could see another decent chance at some rain
and possibly thunderstorms. At this time there is a bit of
variability between models with this system so details are uncertain
beyond the chance of precipitation.
.Aviation...(00Z TAF Issuance)
Issued at 606 PM EST Tue Jan 10 2023
* Widespread IFR ceilings and MVFR visibilities expected
Wednesday midday onward in drizzle and possible showers.
VFR conditions are expected throughout the night into early
Wednesday morning. A broad area of warm moist advection ahead of a
weak low pressure system will bring low ceilings, fog, and drizzle,
along with possibly some showers, into the area late morning into
midday Wednesday, when conditions are expected to rapidly
deteriorate to IFR and remain IFR throughout.
Winds will be below 10KT throughout the period, generally becoming
more southerly with time.
Area Forecast Discussion
National Weather Service Marquette MI
635 PM EST Tue Jan 10 2023
.SHORT TERM...(Through Tonight)
Issued at 259 PM EST TUE JAN 10 2023
Water vapor imagery and RAP analysis show a shortwave moving e
across the western Great Lakes/Ohio Valley. Northern extent of this
wave has aided some very light snow across portions of Upper MI
today from the Keweenaw ese into the eastern fcst area. So far, have
not seen any reports of -dz/-fzdz, but would not be surprised if
some has occurred, especially in areas across the w half where ese
winds are an upsloping wind direction. Fcst soundings have been
showing moisture depth not as deep in that area with cloud deck in
temps that don`t reach -10C. With the low sun angle and low stratus
across the area, temps haven`t changes much today with current
readings in the mid 20s to lwr 30s F.
Tonight, another shortwave, currently over eastern MT/southern
Saskatchewan, will move e, reaching MN Wed morning. As a result,
ongoing weak waa/isentropic ascent will continue tonight and tend to
increase a bit. Fcst soundings generally suggest deeper moisture
across the northern and eastern fcst area and shallower moisture to
the sw. There is variation though at times across the area. As a
result, there will continue to be times tonight where moisture depth
does not extend to temps of -10C or lwr, especially toward the MI/WI
stateline. While that area should be more likely to see ptype of
-fzdz, will simply cover the fcst area with a mix of -sn/-fzdz/-dz.
Models have tended to overdo the QPF today, though it was only fcst
to be very light to begin with. That will probably be the case again
tonight, and opted to shave qpf down a bit. Expect any snow
accumulation to be less than 1 inch, really not much more than a
dusting, as dgz is not in the pcpn production layer. A thin glaze of
ice will be a possibility if -fzdz develops/expands. Given the
continued stratus deck, temps won`t drop much, if at all, from
current readings. In fact, very slight warming may occur thru the
.LONG TERM...(Wednesday through Tuesday)
Issued at 335 PM EST TUE JAN 10 2023
-Wintry mix continues Wednesday
-Light lake effect snow Thursday and Friday
-Friday into weekend dry, could see some sun despite cold Saturday
-Models hinting at a low passing through early next week
Wednesday, wintry mix persists from the overnight period as a weak
low pressure in Wisconsin and PVA from weak 500mb shortwaves provide
forcing for weak precipitation. A break in the wintry mix will have
to wait until at least Thursday, as model soundings keep some areas
of the Upper Peninsula in a sufficently warm surface layer that some
liquid could fall. Even in areas that are subfreezing, the saturated
portion of the profile is below the DGZ, which could lead to a lack
of ice nucleation and resulting freezing drizzle instead.
By late Wednesday, northwesterly flow resumes at most levels,
leading to cooler air and a switch to mostly- to all-snow. The 12Z
ensembles have pulled away from a solution that would have brought a
weak low center along the northern shore of Lake Superior, though
with persistent northerly flow, air aloft is cooling enough to
reintroduce lake effect snow through Friday. The intensity of snow
is limited, as some drier air aloft limits the depth of
precipitating clouds. 850mb temps fall below -10 C in the west half
Thursday afternoon, with the east half reaching that temperature
overnight into Friday.
Ridging aloft and surface high pressure moves into the region Friday
night. The subsidence from this will serve both to dry out the
surface layer and cut off the cold advection that was feeding the
lake effect delta-T`s, ending the snow for the UP. Should clouds
really break up Friday night, Saturday morning`s low could be well
into the single digits for the interior west, though temperatures
should rebound for the high especially if the sun comes out.
For the late weekend and beyond, model solutions diverge
significantly, but the ensembles are keying in on a low pressure
passing in the vicinity of the Upper Great Lakes in the Tuesday time
range, and with NAEFS PWAT percentiles above 97.5, it will be worth
monitoring as the next potential precip-generating system.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 632 PM EST TUE JAN 10 2023
Abundant low-level moisture will remain in place across the area
during this fcst period. As a result, expect IFR/LIFR cigs to
prevail at IWD/CMX/SAW. BR and some light pcpn are also expected at
times, especially at CMX/SAW where ese/se winds are upsloping. So
far, pcpn has been in the form of -sn, but expect pcpn to mix with
or change to -fzdz at times.
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 335 PM EST TUE JAN 10 2023
Southeasterly winds are gusting to 25 knots over the east 2/3 of
Lake Superior this afternoon with a low pressure passing south of
the lake. Overnight, gusts briefly reach 25-30 knots, but diminish
below 20 knots Wednesday morning. Winds remain under 20 knots
across the lake until Thursday afternoon, as gusts reach 20-25
knots. With a ridge approaching Friday, winds in the west half
drop below 20 knots Friday morning and in the east half Friday
afternoon. Winds remain below 20 knots for the remainder of the
Area Forecast Discussion
National Weather Service New York NY
926 PM EST Tue Jan 10 2023
A weak cold front moves south of Long Island tonight followed
by high pressure building across eastern Canada and northern New
England into Wednesday. The front lifts back to the north as a
warm front Thursday night, followed by a cold frontal passage
Friday morning. High pressure builds slowly in from the west
over the weekend. Another frontal system approaches early next
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Forecast is on track with only minor changes needed to reflect
An upper trough tracking across eastern Canada will send a weak
cold front across the area this evening. At the same time, a
southern branch shortwave trough will pass to the south and off
the Mid Atlantic coast. The latter is providing nothing more
than a mid level cloud deck, which is passing over top some
stratus at the base of 4-5 kft inversion. Consensus begins to
clear skies out after midnight as high pressure builds south and
east from eastern Canada. However, the HRRR and RAP have done
particularly well with the lower cloud deck and indicate this
could hang on through Wednesday morning. While not planning be
that aggressive, will be slower than the consensus with any
clearing late tonight.
Preference was toward the warmer end of the guidance due to the
cloud cover with lows ranging from the lower 20s inland to the
lower 30s across the NYC metro. This is a few degrees above
normal. WNW winds will veer to the NE overnight at less than 10
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Another strong PAC system races east across the country
Wednesday into Wednesday night with overrunning clouds working
in from the west in the afternoon and nighttime hours, while
low-level warm advection ensues at night as winds veer to the
E/SE. The latter will allow for low clouds to work in from the
east of the Atlantic.
Wednesday should start off with some sun, however, there is a
small chance that some of the stratus overnight Tuesday lingers
through day. Highs will be a tad cooler and closer to normal
Tuesday, with around 40 inland and the lower 40s at the coast.
There is a decent signal of enough moistening in the low-
levels along with weak low-level lift for perhaps some light
rain/drizzle and/or light snow at the onset (toward daybreak
Thursday), mainly north and west of NYC. Should the cold air be
deep enough for any light snow at the start, it is not expected
to accumulate with temperatures warming through the night. The
warming boundary layer also supports light rain/or drizzle at
the changeover. The one caveat here is whether the dry air aloft
(no ice crystals) keep this is all liquid with a small chance
for patchy freezing rain or drizzle well north and west of the
NYC metro. This would be real brief and confidence for this
scenario is low.
Lows Wednesday night will be around 30 well inland, to the mid
and upper 30s at the coast. However, these lows will be
achieved early in the evening.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
High pressure will continue to retreat into eastern Canada on
Thursday as a frontal system approaches from the west. With a
warm front/stationary front to our south (which may have a tough
time working through the region during the day Thursday) and
onshore flow under mostly cloudy skies, temperatures will be in
the middle 40s to lower 50s.
The main change with this forecast is that models for the most
part have sped up the timing of the fronts. Light overrunning
moisture makes its way into areas north and west of New York
City Thursday morning. There may be enough cold air at the start
for some snow, or a rain/snow mix across mainly northern and
western Orange County and extreme northern Fairfield in
Connecticut. However, it is expected to change to plain rain
everywhere by the late morning into the early afternoon. Little,
if any accumulation is expected. Precipitation will continue to
overspread the area Thursday from west to east into Thursday
night. A period of moderate to heavy rain is possible with the
approach of the cold front Thursday night and as an area of low
pressure over the eastern Great Lakes slowly strengthens.
Additionally, a brief period of windy conditions is possible.
The NBM was showing nearly a 30% chance of gusts near 40 mph for
KJFK after midnight on Thursday night.
The cold front will push offshore Friday morning. The GFS is a
quickest with the cold front, while the ECMWF doesn`t push the
cold front through until late Friday afternoon. So, there is
still some uncertainty with the cold frontal passage, and the
front could push through as late as Friday afternoon.
Additionally, the deterministic models have backed off on the
development of a low pressure system along the frontal boundary
for Friday into Saturday as the upper trough does not negatively
tilt until after it pushes off the East Coast. However, given
all the uncertainty, kept a slight chance of precipitation
Friday night into Saturday.
High pressure builds in for the weekend, with cooler
temperatures, but still above normal for this time of year, with
warming expected from Monday into Tuesday as an upper level
ridge builds over the area.
The next frontal system possibly affects the area next Tuesday.
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A weak cold front passes through the terminals tonight. High
pressure then builds in from north overnight into Wednesday.
VFR. A strato cu deck 3500ft to 4000ft will persist until around
07Z at the NYC metro terminals, then clouds become scattered to
Winds NW to N to light and variable continues overnight.
Wednesday winds will be NE, becoming E during the afternoon,
less than 10kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled amendments.
.OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
.Thursday morning...Mainly VFR, possibly becoming MVFR along the
.Thursday afternoon and night...MVFR or lower possible in rain
or drizzle. LLWS Thursday night into early Friday morning.
.Friday...early morning MVFR becoming mainly VFR. NW winds
.Saturday...Mainly VFR. N-NW winds G20-25kt.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
Minor adjustments were made to winds and gusts to reflect
Sub-SCA conditions are forecast on the waters through Wednesday
night as high pressure builds across eastern Canada and New
England with NE winds veering around to the E/SE around 10 kt.
A period of SCA is expected late Thursday night into Friday as a
frontal system impacts the waters, with gales possible on the ocean.
Peak wind gusts are expected late Thursday night, just prior to and
just after the cold frontal passage. Thereafter, winds diminish.
Waves on the ocean build late Thursday night into Friday morning,
peaking at 6 to 11 ft on the ocean waters late Thursday night into
Friday morning. Waves then slowly diminish into the weekend, but
remain above 5 ft through then on the ocean.
Waves of 5 to 7 ft are possible across the eastern sound zone,
falling below 5 ft by late Friday night into Saturday morning.
A period of moderate to heavy rain is possible late Thursday
night. However, with a quicker moving frontal system, slightly
less rainfall is expected. Minor nuisance flooding is still
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
424 PM MST Tue Jan 10 2023
.DISCUSSION...(This Evening Through Tuesday)
Issued at 203 PM MST Tue Jan 10 2023
20z surface analysis had lee trough from central MT into
southeast MT. Back door cold front from central ND into northeast
NE. Water vapour depicted weak shortwave over western SD with
weakening weak radar returns over the CWA, hardly reaching the
ground most locations. Energy spinning into the west coast main
forecast concern in the near term.
- Compact shortwave will bring band of snow to the far southwest
overnight into Wednesday
- Upper ridge brings unseasonably warm weather end of the week
Tonight/Wednesday, shortwave over central CA will race into
eastern CO/southeast WY. Compact surface low develops over central
WY with tight low level baroclinic zone just northeast of it from
northeast WY into southwest SD. Weak surface high building into
the Dakotas will further tighten thermal gradient tomorrow as low
clouds/fog slip southwest onto the western SD plains. Moderate
frontogenetic forcing ahead of surface low supports a band of
moderate snow over far southwest southern Campbell County with
lighter amounts stretching into the southern Black Hills. 12z
ECMWF EFI paints potential as well as 12z SPC HREF/latest HRRR
runs. Should see at least 2-5" of snow late tonight/Wednesday
morning over southwest southern Campbell County with 1-2"
stretching southeast into far southwest Fall River County. Banded
nature of snow will create strong accumulation gradients, so later
trends will need to be closely watched. Temperatures will be near
Thursday, seasonally cool. Friday/Saturday, upper/thermal ridge
forecast by all guidance with 60-80th percentile forecast highs.
This translates to widespread 40s/50s with a few 60F readings on
the lee side of the Black Hills possible. Pseudo-split upper flow
then develops Sunday into next week with some pops here and there
as well as slightly above normal temperatures per ensemble trends.
.AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening)
Issued At 422 PM MST Tue Jan 10 2023
Mostly VFR conditions are expected at the TAF period. Some light
precipitation may be possible this afternoon for parts of
northeast Wyoming and far western SD. Some fog will begin pushing
into northwestern SD overnight and may bring MVFR/IFR conditions
in any area with fog. Light snow will push into NE WY and far SW
SD after 08z tonight, although snow/visibility impacts should remain
south of KGCC/KRAP.
WY...Winter Weather Advisory from 11 PM this evening to noon MST
Wednesday for WYZ055.