Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/25/23
Area Forecast Discussion
National Weather Service La Crosse WI
547 PM CST Fri Feb 24 2023
.DISCUSSION...(This evening through Friday)
Issued at 200 PM CST Fri Feb 24 2023
Key Messages:
- Brief round of light, fluffy snow tonight - around 1 inch or
less south of I-94, and up to 2 inches further north
- Nice, sunny weekend on tap with gradually moderating temps
- Moisture-laden storm system looks to move through the region
Sunday night into Monday bringing substantial rainfall to much
of the forecast area along with potential for impactful
freezing rain near/north of I-94.
TONIGHT: Brief burst of light, fluffy snow
After a brief lull today in an otherwise active weather pattern, the
next system is on track to bring a bit more light snow to the area
tonight. Watching a couple weak ripples in the 500mb flow currently
over South Dakota/Nebraska. These are poised to slide into the area
later this evening. Just ahead of their arrival, the 850mb ridge
axis currently overhead will depart, giving way to a period of warm
air advection tonight. This is already producing our mid-level
clouds overhead, but forcing will become more focused heading into
this evening. The isentropic forcing will combine with the initial
mid-level shortwave to support a developing band of snow across much
of central Iowa by early evening, eventually filling/extending back
into western Minnesota as the secondary shortwave arrives. This band
of snow will expand as it lifts northeast through the area this
evening.
RAP forecast soundings show the low levels gradually moistening up
from southwest to northeast after 6pm. Thermal profiles will be
supportive for efficient snow production: a 100 to 200mb deep
layer residing within the dendritic growth zone, coincident with
favorable lift while also tapping into a supersaturated (with
respect to ice) layer between about 700-500mb. All this points to
a period of efficient snowfall with high snow-liquid ratios.
However, the snow will be rather brief at any given location,
likely lasting only for a few hours or so. Areas north of I-90,
especially those areas north of I-94, will see the highest snow
potential, perhaps for a bit longer duration, too. All told,
looking at around 1 inch or less south of I-94, perhaps up to 2
inches in Clark and Taylor counties. Will be a light, fluffy snow
that`s easy to clean/blow off pavement.
A dry, mostly sunny weekend is on tap with temperatures gradually
moderating.
SUNDAY NIGHT-MONDAY: Substantial rainfall & freezing rain threat
After a nice break through much of the weekend, attention turns to
the arrival of the next weather system Sunday night into Monday. A
low pressure system is expected to dive down along the West Coast
through the early start of the weekend, before pivoting eastward and
moving across the region Monday. Warm air advection and moisture
will be on the increase ahead of this low pressure system, with
NAEFS mean PW values in the 99.5 percentile relative to climatology
by Monday morning. This will bring our next chance for precipitation
across the forecast area, with ensemble model guidance highlighting
highest 24-hr QPF probabilities (50-80%) for greater than 1"
across northeast Iowa and southwest Wisconsin.
The main challenge with this forecast comes with precipitation
types. 850 mb temperatures among models look to be above freezing,
suggesting that much of the precipitation will fall as liquid to
start. However, surface temperatures will play an important role as
ensemble guidance suggests the potential for freezing rain as the
warm nose develops. There still remain some differences between
ensemble solutions on exact location of this transition to freezing
rain. A slight southern trend in the NBM has been noted with it`s
highest ice probabilities. However, the most current NBM still
highlights areas mainly along and north of I-94 in Wisconsin, with
probabilities of at least 1/10 inch of ice nearing 50%. As colder
air filters in on Monday a transition to some snow looks possible.
Ensemble guidance suggests that highest probabilities (50- 70%)
for greater than 1" snow will remain across central and northern
Wisconsin, with a noted shift even further north in the latest
24.12Z GEFS. Still plenty of time to work out details, but will
need to continue to monitor as heavier rainfall on top of the
frozen/snow covered ground could bring some hydro concerns.
REST OF WORK WEEK:
Behind this system, ensemble guidance suggests another system may
move through bringing precipitation chances (40-50%) to the area.
Still quite a few differences to iron out this far out, so expect
changes in the forecast as details become clearer.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 520 PM CST Fri Feb 24 2023
Precipitation and lower cigs are moving into northeast Iowa at TAF
issuance. Low level dry air inhibiting initial onset and
therefore flight restrictions. Snow tonight will move through
quickly, reducing cigs/vis to IFR for a short while. Skies clear
for tomorrow, with southwest winds.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Kurz/EMS
AVIATION...JAR
Area Forecast Discussion
National Weather Service Boston/Norton MA
1010 PM EST Fri Feb 24 2023
.SYNOPSIS...
Northwest winds ease with falling temperatures tonight with
below normal temperatures. Frigid start Saturday but
temperatures rebound closer to seasonable by Sunday. Cloudy
conditions with light rain or rain or snow mix Sunday. While
uncertainty remains large, we are monitoring a potential winter
storm Monday night through Tuesday night that could bring at
least a plowable snow accumulation to Southern New England.
Brief dry weather for Wednesday but our weather pattern remains
active for late in the week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Update: 10 PM
Temperatures continue to fall steadily this evening, following
the trends set during the previous update. Most locations are in
the 20s with a few upper teens sprinkled in across northern CT
and western MA. Regional radar shows very fine streaks of
moisture coming off of Lake Ontario as the lake is not covered
in ice, would not be surprised to hear reports of light
snow/flurries in parts of western MA or NW CT.
No wholesale changes made during this update, stay warm this
evening!
Previous discussion:
640 PM Update:
Wind Advisory for the Berkshires has been cancelled as gusts
have been around 35 mph or less. While shallow CAA will continue
and maintain steep lower level lapse rates, decreasing mixed
layer wind speeds should allow for gradual decreases in gusts
areawide.
Observed temps were running several degrees warmer than prior
indications, likely due to the mixing/continued NW breezes. Thus
opted to raise temps up through about 06z using a mix of
continuity and the recent bias-corrected HRRR guidance. A more
precipitous fall in temps anticipated after midnight as winds
begin to ease more appreciably. Still will have wind chills
in the single digits below zero near and north of the MA Pike
for the second half of the overnight.
Ocean effect cloudiness lies just offshore of Cape Cod, with
some tendency for it to shift closer to the Outer Cape later
overnight. Though a few flurries are possible given some
saturation in the dendrite growth layer, sounding progs show a
considerable sub-cloud drier air so likely more than exception
than the rule.
Previous discussion:
Deep northwest flow behind an exiting Arctic cold front
continues to support a very cold air mass over southern New
England. Temps at 925 hPa drop down to -15 Celsius giving us our
coldest overnight temperatures since the Arctic outbreak we had
at the beginning of the month. Clear skies overnight will
support one half of optimal radiational cooling, but light winds
remain a question. Gusty northwest winds from this afternoon
are expected to diminish overnight, but there is some
uncertainty where, when, and if the atmosphere will decouple to
support maximum radiational cooling. Most hi-res model soundings
support this outcome across the northern interior locations
while areas near the coast support stronger winds overnight that
would limit cooling. Given the uncertainty, a blend of CONSMOS
and NBM offers a fair solution where low temperatures across
much of the interior bottom out in the single digits. Further to
the south and east, lows in the low to mid teens should be more
common. Wind chill temps will range from single digits to as
much as 8 degrees below zero across northwestern MA tomorrow
morning.
Also of note for tonight`s forecast is the potential for ocean
effect snow showers over the outer cape. Cool northwest flow over
the relatively warmer Cape Cod Bay may be enough to support a period
of ocean effect snow showers, mainly for outer Cape Cod. The
limiting factor will be mid-level moisture. Model guidance is
resolving high moisture content in the 925-850 hPa layer just
slightly off the outer coast of Cape Cod. Some model guidances keeps
this moisture offshore and suppresses the potential for ocean effect
snow, while other hi-res models like the HiRes Window - ARW bring
this moisture over land and support a period of snow showers after
midnight. Given the uncertainty, left PoPs at slight chance
overnight. Accumulations would be limited to a dusting to an
inch.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Tomorrow
Surface high pressure settles over The Northeast tomorrow and
supports quiet weather for the first half of the day, with the
exception of potential ocean effect snow over the outer Cape. Air
mass remains anomalously cold with 925 hPa temps still around
-15 Celsius. Thus most locations will have high temperatures
confined to the 20s or perhaps even lower across the north and
western areas. By early to mid afternoon, a weak upper-level
short-wave at 500 hPa will be traversing over The Northeast.
This may support a dusting to an inch at most of snow during the
mid-afternoon hours tomorrow. High pressure will support
generally light and variable winds.
Tomorrow Night
Any remaining snow showers come to an end tomorrow night. High
pressure will shift east of southern New England, but will continue
to influence quiet weather tomorrow night. Winds will be light, but
cloudy skies should limit efficient radiational cooling.
Nonetheless, expect another chilly night and start to the day Sunday
with all of southern New England expected to observe low temps in
the the high single digits to upper teens. Coolest locations once
again to the north and west while milder temperatures will be
observed to the south and east.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Highlights:
* Passing weak system Sun brings a light rain/snow mix with limited
accumulation. Cloudy but temps seasonable to slightly above
normal.
* Still monitoring potential for a winter storm around Mon night to
Tue night in SNE, which could bring at least a plowable snow
accumulation and/or a snow-to-wintry-mix for the coastal plains.
It remains an evolving forecast with large uncertainty.
* Brief dry weather Wed, but pattern remains active/unsettled Thu-
Fri.
* Temps around seasonable levels.
Details:
Sunday:
Not too much has changed regarding the forecast for Sunday, with a
weak amplitude low pressure moving SE from NE Ontario into interior
northern New England Sun aftn. Overall, QPF looks really limited and
warm advection should also force a predominant rain or rain/wet snow
mix except light snow in the communities along and north of Route 2
and especially NE MA. Given anticipated timing being in the aftn,
would expect any snow to melt on pavement yielding wet roads. Again
overall impacts are limited to a nuisance-level. Considerable
cloudiness with highs mid/upper 30s to the lower 40s range. Clearing
and drying for the evening, though cold advection will lead to NW
gusts at least first part of the evening, which could potentially
slow temperature falls to a limited extent. Lows mainly low-mid 20s
south of the MA Pike, upper teens/near 20 north of the Mass Pike.
Monday:
Brief period of dry weather under sfc ridging and brief geopotential
height rises at the 500 mb level. Cold and dry advection through the
day but the cold advection looks offset by mostly full sun (clouds
arrive late). Highs mid-upper 30s/near 40.
Monday Night through Tuesday Night:
This period likely to be a focus during the early to midweek period,
with global ensemble solutions and their operational runs continuing
to advertise a winter storm with a potential for accumulating snow
and/or a snow-to-wintry mix for the southern and eastern coastal
plains. It stems from a powerful shortwave disturbance aloft now
near the CA/OR West Coast, a feature which is expected to move NE
into the upper Midwest early next week, and deamplify as it does so.
Per most ensembles and deterministic solutions, energy transfer then
occurs near the mid-Atlc coast early Tue to a secondary low pressure
which then traverses east along our southern waters (in vicinity of
40N latitude, give-or-take) thru Tue. Lingering and potentially
lighter wrap-around moisture may continue to affect eastern SNE into
Tue night.
There remain a number of uncertainties regarding this system and its
complex evolution, and among them include how and where the energy
transfer from primary to secondary lows takes place, the track of
this secondary low pressure, and the extent to which warmer air
aloft could force a changeover to wintry mixed precip along with
modifying onshore flow over to perhaps rain for a time. This latter
source of uncertainty is more aimed at the southern and eastern
coastal plains of SNE.
Given the uncertainties stated, it remains too early to provide
specific snow accumulations as yet. Did note that NBM-4.1 based snow
probabilities exceeding 4 inches are well above 60% for areas N/W of
I-95, and around 30-50% for the BOS-PVD urban corridors, less near
the immediate coast. Similar NBM-4.1 based exceedance probs of 8 or
more inches are lower areawide, but are around 40-60% around the
terrain of Worcester County and in the Berkshires. Plowable snow
remains a currently favored outcome and think the probs drive home
the point that interior areas of SNE have a greater potential to
stay as snow for a longer period of time, with more mixover near the
coasts. Will also mention that the NBM-4.1 based probs during the
daytime hrs only utilize today`s 00z guidance; thus, while the GFS
is more or less sticking to its persistence, did note that today`s
ECMWF has course-corrected south a bit in today`s 12z solution. EPS
does show a 3-cycle trend for North Atlantic/NE Quebec sfc ridging
to build southward into interior New England early Tue, which would
suppress the system slightly further south. It would still favor
accumulating, plowable snow for most but it nonetheless adds to
greater level of uncertainty in today`s depictions and potential
outcomes.
The take-away is that the potential still exists for accumulating,
plowable snow accumulations, perhaps mixed with rain or wintry mix
near the southern and eastern coastal plains. It does look like the
focus is centered around Mon night thru Tue night. However there are
continued uncertainties which limit specifics on snow accumulations
at this point. It remains an evolving forecast and we continue to
advise those to keep abreast of the forecast over the weekend.
Wednesday through Thursday Night:
Overall forecast regime remains an active one, and while brief
shortwave ridging develops for Wed, we continue to keep tabs on
either one or a series of low pressure areas Thurs and/or into Fri.
Didn`t stray far from NBM for this period but these system(s) will
need to be monitored as well, in addition to that for Mon night -
Tue night. Temps trend seasonable or slightly above normal.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update:
Tonight: High confidence.
VFR. SCT-BKN VFR-MVFR ceilings especially after midnight for
HYA/ACK with possible flurries but not resulting in
restrictions to visby. NW winds 13-18 kt with gusts to 24 kt
early, gusts decrease 04-06z; decreasing sustained winds after
06z to 5-10 kt.
Tomorrow...High Confidence
VFR for the first half of the day. Snow showers possible after
18Z. VFR ceilings should persist, but marginal MVFR ceilings
around 030 feet possible. Light northwest winds early becoming
light out of the southwest by the afternoon.
Tomorrow Night...High Confidence
Mainly VFR with patchy MVFR ceilings possible over the western
areas. Light and variable winds.
KBOS Terminal...High confidence.
KBDL Terminal...High confidence.
Outlook /Sunday through Wednesday/...
Sunday: Mainly VFR, with areas MVFR possible. Windy with local
gusts up to 30 kt. Slight chance RA, slight chance SN.
Sunday Night: VFR. Windy with areas of gusts up to 30 kt.
Monday: VFR. Breezy. Slight chance SN.
Monday Night: Mainly IFR, with local MVFR possible. Windy with
gusts up to 35 kt. SN.
Tuesday: Mainly IFR, with areas MVFR possible. Windy with gusts
up to 35 kt. SN, RA.
Tuesday Night: VFR. Windy with local gusts up to 30 kt. Chance
SN, chance RA.
Wednesday: VFR. Breezy.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight
Gale force winds gradually diminish overnight as high pressure
builds over the coastal waters. Ocean effect snow showers possible
around and east of outer Cape Cod. Freezing spray likely across the
eastern coastal waters. Seas gradually subsiding to 2 to 3 feet
across the near-shore marine zones.
Tomorrow
Diminishing winds and subsiding seas continue as high pressure
dominates the coastal waters. As high pressure shifts east by the
mid-afternoon, winds become steady out of the west/southwest.
Additional snow showers possible.
Tomorrow Night
Relatively calm across the coastal waters tomorrow night with 1 to 2
foot seas and light westerly winds.
Outlook /Sunday through Wednesday/...
Sunday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas locally approaching 5 ft. Chance of snow, slight
chance of rain.
Sunday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft. Chance of rain.
Monday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Monday Night: Low risk for gale force winds with gusts up to
35 kt. Local rough seas. Rain, chance of snow. Visibility 1 to
3 nm.
Tuesday: Low risk for gale force winds with gusts up to 40 kt.
Rough seas up to 13 ft. Rain.
Tuesday Night: Moderate risk for Small Craft Advisory winds
with local gusts up to 30 kt. Rough seas up to 12 ft. Chance of
rain, slight chance of snow.
Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Rough seas up to 11 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 10 PM EST this evening for ANZ230.
Small Craft Advisory until 7 AM EST Saturday for ANZ231>235-
237-251-255-256.
Freezing Spray Advisory until 7 AM EST Saturday for ANZ231-232-
250-251-254.
Small Craft Advisory until 11 AM EST Saturday for ANZ250-254.
&&
$$
SYNOPSIS...Loconto/RM
NEAR TERM...Loconto/Gaucher/RM
SHORT TERM...RM
LONG TERM...Loconto
AVIATION...Loconto/RM
MARINE...Loconto/RM
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
907 PM CST Fri Feb 24 2023
...New UPDATE...
.UPDATE...
Issued at 901 PM CST Fri Feb 24 2023
Frontal boundary is nearly stationary from south of VCT to near
Lake Corpus Christi to south of LRD. The boundary may drift a
little to the south over the coastal plains as latest analysis
shows high pressure ridge nosing southward from central Texas
toward the Victoria Crossroads. Used a blend of latest CONSShort
and 00Z HRRR for placement of front and temperatures for tonight.
Expect the frontal boundary will drift northward as warm front
on Saturday. Bumped high temperatures for Saturday. Areas of fog
will likely affect the coastal region ahead of the frontal
boundary. Visibility is lowering along the coast with VSBY at
2-3 NM along the coast. Will keep current Dense Fog Advisory for
the bays and near shore waters as is, starting at 06Z Saturday.
&&
.SHORT TERM...
(Tonight through Saturday night)
Issued at 311 PM CST Fri Feb 24 2023
Deterministic runs continue to predict a quasi-zonal upper level
pattern over the CONUS during the period, except for an upper
disturbance predicted to move slowly eastward near the West Coast.
MSAS depicts a frontal boundary across the CWA this afternoon.
This boundary is expected to meander over the CWA during the
period. Notwithstanding the near/above normal PWAT values
expected, do not expect significant precipitation associated with
this boundary, when considering the expected thermodynamic
profile/structure, with dry conditions above 850mb, small afternoon
CAPE and strong near surface inversions/zero CAPE at night.
Expect advection fog again tonight/early Saturday over the
bays/nearshore waters, which may enter the Coastal Bend, mainly
east of US Highway 77. Very low ceilings are expected tonight and
decided to forecast patchy fog over the Coastal Plains based on
the possibility of stratus-lowering fog, yet expect mainly MVFR
visibilities. Advection fog possible again Saturday night.
Extended the High Risk of rip currents based on current/expected
swell heights/periods. Temperature forecast strongly a function of
the position/timing of the frontal boundary. Decided to forecast
maximum/minimum temperatures similar to those from the SREF
ensemble mean.
&&
.LONG TERM...
(Sunday through next Thursday)
Issued at 311 PM CST Fri Feb 24 2023
Key Messages:
-Elevated fire weather conditions possible on Monday and again late
next week
-Temperatures to remain above normal through late next week
An upper level trough will move east from the Four Corners into the
Great Plains Sunday into Monday morning. With high pressure sitting
in the Gulf, expect the pressure gradient to tighten as the trough
moves through the state and a 30-40 kt LLJ develops in response.
This will lead to an increase in winds at the surface overnight
Sunday into Monday morning. Winds should decrease as the trough
lifts northeast Monday afternoon. Skies Sunday into Monday morning
will be mostly cloudy due to isentropic ascent and moisture in the
lower levels. No mention of PoPs in the forecast; however, if
isentropic ascent is strong enough, could see isolated streamer
showers.
Conditions will dry significantly behind the front Monday afternoon,
with RH values dropping into the teens to low 20s for the majority
of S TX. While winds will be decreasing in the afternoon, fuel
levels remain dry, and RH values critically low. Thus, elevated fire
weather conditions remain possible during the day Monday.
Expect quiet weather to continue through late next week. Cloud cover
will increase Wednesday with isentropic ascent interacting with
moisture from onshore winds.
Persistent S to SW winds will keep warm temperatures over S TX
through Thursday of next week. Expect highs to be in the 80s to low
90s, with some areas in the Rio Grande Plains and Brush Country
reaching into the mid-90s. Lows will generally be in the 60s.
Temperatures should cool off Friday as another cold front pushes
through the area. At this time, highs on Friday are projected to be
in the 70s area wide. Could see isolated showers Thursday night into
Friday with the front. Highest PoPs lie in the Victoria
Crossroads/Northern Coastal Bend and the Coastal Waters.
&&
.AVIATION...
(00Z TAFS)
Issued at 602 PM CST Fri Feb 24 2023
Satellite imagery and observations show the frontal boundary from
just south of Victoria to near Lake Corpus Christi to north of
Laredo with only a slow drift to the southeast. This boundary may
make it to near a PKV-ALI-LRD line around 06Z, then stall or drift
northward Saturday morning. MVFR ceilings will occur near and
behind the boundary over the coastal plains this evening, while
stratus and fog will develop along the coast and move inland to
near the stalled boundary through the overnight hours. MVFR/IFR
ceilings along the coast will deteriorate to IFR/LIFR with MVFR
to IFR vsbys through 14Z Saturday. MVFR ceiling will move into
the Brush Country for the overnight and continue through Saturday
morning. Fog will lift for coastal region 14-15Z with improvement
to MVFR for rest of the morning and VFR for the afternoon.
&&
.MARINE...
Issued at 311 PM CST Fri Feb 24 2023
Weak to moderate onshore flow expected to persist tonight through
Saturday night. Expect areas of advection fog tonight/early
Saturday. Issued a Dense Fog Advisory for the bays/nearshore
waters 06-16z Saturday, based primarily on the SREF probabilities.
Advection fog may occur again Saturday night. Moderate to strong
onshore flow will continue Monday morning. A front will move
offshore by midday Monday with a weak to moderate north to
northwest flow developing in its wake. Offshore flow is short
lived as onshore flow quickly returns by Tuesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 68 77 66 79 / 10 10 10 0
Victoria 58 74 65 80 / 10 10 10 0
Laredo 63 85 68 87 / 10 10 10 0
Alice 66 80 65 83 / 10 10 10 0
Rockport 66 72 64 76 / 10 10 10 0
Cotulla 59 78 67 86 / 10 0 10 0
Kingsville 69 80 66 82 / 10 10 10 10
Navy Corpus 68 73 65 74 / 10 10 10 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 6 AM CST Saturday for TXZ345-442-443-
447.
GM...Dense Fog Advisory until 10 AM CST Saturday for GMZ231-232-236-
237-250-255.
&&
$$
SHORT TERM...TMT/89
LONG TERM....HA
AVIATION...TMT
Area Forecast Discussion
National Weather Service Wichita KS
551 PM CST Fri Feb 24 2023
...UPDATE TO AVIATION DISCUSSION...
.UPDATE...
Issued at 324 PM CST Fri Feb 24 2023
Looking at current radar trends, have decided to go with a winter
weather advisory for this evening, for areas along the KS
Turnpike and for areas along Highway 54, as pockets of freezing
rain may lead to some slick spots during the evening commute.
Ketcham
&&
.SHORT TERM...(This evening through Monday night)
Issued at 250 PM CST Fri Feb 24 2023
Bottom line up front: A slight chance of a wintry mix early this
evening. A warming trend for Sat/Sun and a chance of strong to
severe storms for Sun aftn/evening.
Latest RAP shows low level moisture transport is increasing across
south central KS this afternoon. This moisture transport is
overrunning shallow cold air still in place across southern KS, with
surface temperatures in the mid to upper 20s. Latest radar trends
showing a gradual increase in very light echos, probably in the form
of light freezing rain (sprinkles) and freezing drizzle, as the warm
nose overruns the cold air. The moisture transport associated with
the right rear quad of the upper jet will slowly shift into areas
east of the KS Turnpike for early this evening and into SE KS by
later this evening. Given the patchy nature, think some very light
glazing may occur on elevated surfaces, with patchy slick spots
possible. But think widespread impacts will be too limited for a
winter weather advisory as streets and overpasses stay mainly dry.
For the rest of tonight into Sat, the stubborn cold air will be
difficult to get rid of, with warm advection expected with the next
system not arriving till Sat afternoon. Also lots of cloud cover
will inhibit the warm up as well on Sat, so decided to go below most
guidance solutions for max temperatures on Sat. With the warm
advection in the afternoon, temps will be warmer than today, but
still about 10 degrees below normal.
Attention than turns to Sun, as a vigorous shortwave in the Desert
SW Conus races east across the southern Rockies into the Plains by
Sun night. The GFS and ECMWF are similar in this shortwave taking
on a negative tilt as it moves into KS, with cyclogenesis leading to
a low pressure area developing over NW KS with some sort of dryline
extending south from the low into OK and TX across western KS for
Sun afternoon. Models have been coming in a little slower with this
system, which would suggest initial storm development may be west
and southwest of our forecast area for Sun afternoon, with a weak
elevated mixed layer, keeping the storms isolated initially, But as
the cap weakens, widespread convection will eventually race east
into the area for Sun evening. Some question on moisture quality and
moisture transport this far north as well, with GFS showing MLCAPES
only around 250-500 J/KG in southern KS.
Impressive bulk shear will be associated with this system, with
directional shear showing some turning with height, for Sun
afternoon before the directional shear becomes more unidirectional
into Sun evening. So the best chance for more discrete storms along
the dry line will probably be for areas southwest of our area and
south into OK. So thinking convection will evolve into more of a
linear line of storms with some embedded strong to severe storms.
Think the main strong/severe threat will be hail up to to quarter
size and damaging winds to 60 mph. If a storm can stay discrete
across southern KS, there is a small tornado threat along the KS/OK
border late Sun afternoon, given 0-1km CAPE around 1000 J/KG, before
the storms "line out" for Sun evening. Current day 3 slight risk
looks reasonable with a slight risk for much of the area. Once the
convection becomes more widespread in the evening hours, higher than
normal precipitable water values suggest some pockets of much needed
heavy rainfall for a good portion of the area as the system races
east-northeast Sun night.
A strong cold front on the backside of the system will sweep most of
the convection to the east of the area late Sun night. Not expecting
much a cool down behind the front, as downslope flow will lead to
another above normal temperature day on Mon.
Ketcham
.LONG TERM...(Tuesday through Friday)
Issued at 250 PM CST Fri Feb 24 2023
The start of the week looks dry, with slightly above normal
temperatures. Another cold front looks to "backdoor" into the area
either Wed night or early on Thu. This will push temperatures back
below normal for the end of the week. Another quick hitting
shortwave moves across the area for Thu and Thu night. As this
system moves over the area, a mix of light rain/snow may move across
the area. Not alot of moisture is available for this system, so
think impacts will be minimal.
Ketcham
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 531 PM CST Fri Feb 24 2023
Light freezing rain has already come to an end in the Wichita area
and will quickly exit the Flint Hills area over the next hour or
two. Some lingering MVFR cigs will impact KICT and KCNU this
evening before slowly clearing from west to east. VFR is
anticipated at KICT by 04-06Z while low cigs impact KCNU through
10-12Z tomorrow morning. Light and variable winds will veer to the
south/southwest and slowly increase as we move through the day on
Saturday becoming breezy over central KS tomorrow afternoon with
some gusts to around 20 mph possible at KRSL and KGBD.
&&
.FIRE WEATHER...
Issued at 250 PM CST Fri Feb 24 2023
Elevated Grassland Fire conditions will return on Sunday as
southerly winds increase ahead of the next weather system Sunday
afternoon and Sunday night. Most areas are likely to see very
high grassland fire conditions through the afternoon Sunday. Once
the showers and thunderstorms begin, the fire danger will be
significantly reduced.
Conditions for Monday are a question mark. Considering the amount
of rain that is currently expected during the night Sunday, the
grassland fire danger will likely be reduced for Monday. Windy
conditions expected for Monday afternoon may dry fuels out enough
to bring very high grassland fire conditions back. This will
depend on just how much rain falls.
Ketcham
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 21 45 38 63 / 0 0 10 50
Hutchinson 19 45 35 63 / 0 0 0 50
Newton 19 45 37 62 / 0 0 10 40
ElDorado 22 45 39 62 / 10 0 10 40
Winfield-KWLD 22 45 41 64 / 20 0 20 50
Russell 14 50 32 69 / 0 0 0 40
Great Bend 15 49 33 68 / 0 0 0 40
Salina 17 49 34 66 / 0 0 0 40
McPherson 17 47 35 64 / 0 0 0 40
Coffeyville 29 48 43 64 / 30 0 30 50
Chanute 25 48 40 64 / 40 0 20 40
Iola 25 48 40 62 / 40 0 20 40
Parsons-KPPF 27 48 42 64 / 30 0 20 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 PM CST this evening for KSZ052-
053-068>072-083-094>096.
&&
$$
UPDATE...BDK
SHORT TERM...Ketcham
LONG TERM...Ketcham
AVIATION...MWM
FIRE WEATHER...Ketcham
Area Forecast Discussion
National Weather Service Indianapolis IN
932 PM EST Fri Feb 24 2023
.Forecast Update...
Issued at 932 PM EST Fri Feb 24 2023
Brief period of 290K isentropic lift and moisture, increasing from
top down per lowering condensation pressure deficits and BUFKIT
soundings, support leaving chances for precip overnight. That said,
most of the obs over northern Illinois and Missouri, where the
current 30+ echoes are, were not revealing any precip reaching the
ground.
Latest ACARS sounding along with BUFKIT soundings suggest any light
precip will fall mostly as rain. Significant cloud cover should keep
slightly above freezing temperatures at bay and possibly slow rise
overnight.
&&
.Short Term...(This evening through Saturday)
Issued at 314 PM EST Fri Feb 24 2023
- Mostly cloudy Tonight; sprinkles, freezing drizzle or flurries
possible.
- Mostly Sunny and warmer on Saturday
Surface analysis early this afternoon shows a large area of cold
high pressure over the Great Lakes. This system was providing cold
northeasterly surface flow across Central Indiana. Aloft water vapor
showed a nearly zonal flow across the plains states and into the
Ohio Valley. A weak short wave was found over KS/OK, along with a
second wave over TN. The Tennessee system was producing some rain
across Arkansas and Tennessee, but this will remain south of Central
Indiana. The plains wave was failing to produce much other than a
few clouds. GOES16 shows partly cloudy across Central Indiana,
however some cold air advection stratus was found across the
northern third of Indiana. These clouds were remaining north of the
forecast area and as winds were becoming more northeasterly, they
are not expected to impact Central Indiana. Some mid and high clouds
were invading from the west and this was associated with the
previously mentioned weak short wave approaching from the plains.
The lower levels of the atmosphere remained quite dry as dew point
temperatures across the area were in the teens.
Tonight...
The surface high pressure system to the north is expected to
continue to progress eastward, allowing an easterly lower level flow
of dry air across Central Indiana. Meanwhile aloft the short wave to
the west is expected to progress across Indiana. GOES16 shows some
mid and high level clouds with this feature, but there is little in
the way of precipitation. Forecast soundings overnight continue to
show dry air within the lower levels and models suggest surface dew
points fail to get higher than the lower 20s. Mid levels become
saturated amid weak warm air advection ahead of the short wave, but
lower levels remain dry. HRRR suggests a weak wave of very light
scattered precip pushing across the area overnight. Given the dry
lower levels, confidence is low for any measurable precipitation.
However a freezing drizzle sprinkle or flurry cannot be ruled out.
Any pops that are included will be quite minimal. Dynamic forcing
from the quick moving wave appears to exit the area by 12Z, leading
to a return of subsidence. Given the expected cloud cover will trend
lows toward the upper 20s and lower 30s.
Saturday...
Models suggest the continuation of zonal flow aloft on Saturday as
weak ridging begins to build across the western plains. This once
again allows subsidence to return to Central Indiana. Forecast
soundings on Saturday reveal a dry column in the wake of the
departed short wave. Convective temperatures appear unreachable,
thus we will expect mostly sunny skies, with only the stray passing
high cirrus cloud aloft. Meanwhile at the surface, another area of
high pressure is suggested to reorganize over KY and TN, leading to
warmer westerly surface flow across Indiana. Thus highs in the upper
40s to lower 50s will be expected.
&&
.Long Term...(Saturday night through Friday)
Issued at 314 PM EST Fri Feb 24 2023
Temperatures throughout the long term period will be above normal
with highs oscillating from the 50s to 60s and lows from the 30s to
40s as a couple of systems move across the region.
The period will start out quiet as ridging passes through the region
aloft. An upper low will move in from the southwest and southern
plains reaching the Great Lakes region by early Monday. This system
will bring precipitation chances starting in the SW as early late in
the day Sunday due to isentropic lift along the warm front moving
northward. The surface low itself and the associated cold front,
which will have near definite rain chances with it, will enter the
forecast area more so during the day Monday. The best chances for
rain and storms will be from early morning Monday into midday with
slight chances of thunder embedded. Storm total QPF currently looks
to be about half an inch to an inch which shouldn`t cause many
issues in terms of flooding. The main story with this system will be
the increased gradient winds set to move in along and behind the
cold front. A LLJ, with a centroid of 60-70 kts at 850 mb will pass
overhead which should mix down to the surface from prior to sunset
throughout the rest of the day with surface winds potentially
getting to around 50 mph at times. Within storms, some stronger
winds could be embedded. Winds will drop some by monday night and
will further weaken through the day Tuesday.
Temperatures will dip some Tuesday behind the cold front but are
expected to rebound quickly by Wednesday as southern to southwestern
surface flow returns. A surface high will move in behind the early
week system, leading to a break in precipitation for midweek.
At the end of the period, there remains quite a bit of variability
between models thus leading to quite a bit of uncertainty. It does
appear that some sort of upper wave will bring precipitation chances
somewhere between the Great Lakes and Tennessee Valley during the
latter half of the week as well as slightly lower temperatures. Will
continue to monitor and see where models converge on solutions.
&&
.Aviation...(00Z TAF Issuance)
Issued at 536 PM EST Fri Feb 24 2023
Impacts:
- VFR flying conditions and winds less than 10 knots through
Saturday night
Discussion:
Good flying weather is expected through Saturday night under
the influence of high pressure over the Great Lakes. Mid and
high clouds will roll through in zonal flow well ahead of
the low pressure system looming off the Pacific coast.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...MK
Short Term...Puma
Long Term...KH
Aviation...MK
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
941 PM CST Fri Feb 24 2023
.UPDATE...
Issued at 921 PM CST Fri Feb 24 2023
Forecast looks on track and plan no changes to going advisory. A
combination of light freezing rain, sleet, and snow is occurring
across the northern CWA where temperatures are at or below
freezing. Farther south, light rain is falling across central and
east central Missouri into southwest Illinois where temperatures
are in the mid-upper 30s. Regional radar is showing heaviest
precipitation across northern half of the CWA with lighter
precipitation extending back into western Missouri. RAP is showing
weak mid-level frontgenesis moving east of the area late tonight
which falls in line with latest run of the HRRR which moves
precipitation east of the area by Saturday morning. Did not change
forecast temperatures, so still expect icing to stay north of
I-70 in the advisory area.
Britt
&&
.SHORT TERM... (Through Late Saturday Night)
Issued at 300 PM CST Fri Feb 24 2023
KEY MESSAGES:
1) Light freezing rain is expected across portions of northeast
Missouri and west-central Illinois this evening through very early
tomorrow morning, A light glaze of ice may produce slippery
roadways and cause travel impacts.
2) A dynamic low pressure system will bring widespread showers and
a few thunderstorms between Sunday night and early Monday, along
with periods of gusty and at times strong winds early Monday
through Monday evening.
Tonight, an upper level shortwave trough will pass through the Upper
Midwest, driving a weak cold front through the CWA. This front will
pair with incoming 700-850 mb moisture to produce precipitation
throughout the region tonight. Temperatures will dictate
precipitation type, with northeast Missouri and west-central
Illinois being the most likely regions to fall below freezing and
experience wintry precipitation. Model soundings indicate that
freezing rain will be the primary precipitation type in locations
that are able to reach sub-freezing temperatures overnight. Although
accumulations will be light, there is the potential for impacts due
to glazing ice. For that reason, we decided to issue a Winter
Weather Advisory in our northern third tier of counties in Missouri
and Illinois from 00z-10z.
Precipitation is expected to exit the area by 12z tomorrow morning.
Clearing skies and warm air advection during the afternoon will
result in a return to near normal temperatures, kicking off a
warming trend that will last through mid-week.
Jaja
.LONG TERM... (Sunday through Next Friday)
Issued at 300 PM CST Fri Feb 24 2023
The primary item of interest during the long term period will be the
arrival of a rather dynamic low pressure system late Sunday through
Monday, which will bring a round of gusty winds and widespread rain,
along with potentially a few thunderstorms.
Before we get there though, daytime Sunday is expected to remain
relatively uneventful as almost the entire Mississippi river valley
will be positioned squarely underneath an upper level ridge. The
primary consequence of this, along with increasing southerly flow
and warm air advection, will be a noticeable ramp-up in temperatures
from the prior day. 850 mb temperature ensemble means reach near the
90th percentile during the day Sunday, and while increasing cloud
cover will likely prevent the surface from fully realizing its
potential, we can still expect to see high temperatures reaching
around 10 degrees above seasonal normals.
Meanwhile, there remains some potential for light showers to develop
across the Ozarks and spread northward during the day Sunday due to
a combination of isentropic ascent and increasing moisture.
Considering that the bulk of the stronger forcing from the
approaching storm system will remain well to our west throughout the
day, this light rain may be enough to wet the ground at times but
will otherwise be uneventful. In general, expect a mild but at times
cloudy and gloomy Sunday, with breezy but not particularly strong
southerly winds.
Much more notable changes are expected between Sunday evening and
overnight, as a compact but dynamic and negatively tilted shortwave
will pivot northeastward out of the central plains and into the
lower Missouri river basin. In response to this trough, a deep
surface low is expected to develop, which will drive strong
southerly return flow and rapid moisture return ahead of it as it
curls northeastward. Not only this, but a tightening pressure
gradient will introduce the potential for strong surface winds,
although exactly how strong these winds will be and where they`ll
occur remain somewhat in question.
Before we dig too much into the wind though, the first item to
discuss will be the potential for widespread rain and possibly a few
thunderstorms. The combination of strong upper level forcing,
anomalously high moisture content approaching the 99th percentile,
robust isentropic ascent and a passing cold front will undoubtedly
produce widespread rain throughout the area, the bulk of which is
expected to fall during a relatively brief period between late
Sunday night and early Monday morning. Rain rates may be heavy at
times, but the progressive nature of this system should limit the
potential for impacts related to flooding. Not only this, but
model projections continue the limit the potential for significant
instability (500 J/kg or more), and as a result, the potential
for any severe thunderstorms remains rather low this far east.
Side from the widespread soaking rain, the most notable feature
of this storm may end up being wind speeds. As mentioned
previously this low will feature a tight pressure gradient,
although there remains some uncertainty regarding the magnitude,
duration, and timing of the strongest surface winds. Within the
warm sector late Sunday through early Monday morning, model
soundings indicate that downward momentum transfer potential will
not be particularly high, although convective elements could allow
this on a smaller scale given the presence of a strong low level
jet. Rather, more widespread downward mixing of stronger winds is
more likely along and behind a passing front and within a regime
of modest cold air advection, and very near the surface low. This
region will see the best potential for impactful surface winds,
with gusts reaching 45 kt well within reason, and exactly where
they occur will likely depend heavily on where specifically the
surface low track. In short, this appears to be most likely across
areas along and north of I-70 during the day Monday, with
numerous ensemble members continuing to produce 45+ mph gusts, and
ensemble means nearing this level as well.
Wind speeds will diminish quickly Monday evening, and a period of
relatively quiet weather is expected Tuesday and Wednesday in spite
of the establishment of southwesterly flow aloft. Temperatures are
also expected to rebound quickly Tuesday thanks to a quick return to
southeast return flow in the low levels, followed by rather gusty
southwesterly winds Wednesday afternoon. In any case, ensemble
guidance is in relatively good agreement that Tuesday and Wednesday
will be lacking in precipitation.
A more active weather pattern is expected to return sometime between
Wednesday and Thursday, as a series of shortwaves is expected to
begin impacting the region. As mentioned in the previous discussion,
there remains very little consensus among ensemble guidance
regarding the timing and potential impacts of these systems,
although Wednesday night through the end of the work week represents
the next best opportunity for noteworthy precipitation across the
region. The general consensus for above normal temperatures in the
long term also largely persists, although we do observe wider
temperature spreads and a slight downward trend late in the work
week.
BRC
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 536 PM CST Fri Feb 24 2023
Light precipitation is expected at UIN, COU, and JEF between
01-05Z and at the St. Louis area terminals between 04-09Z.
Temperatures at UIN will be at or below freezing, so light
freezing rain is expected with trace icing. Elsewhere,
temperatures are expected to be at or above freezing, so light rain
expected. I still can`t rule out a low chance of light freezing
rain if temperatures fall lower than expected. Low VFR or high
MVFR ceilings are expected through mid morning Saturday before
ceiling become VFR through the remainder of the period.
Visibilities will be MVFR or VFR during the precipitation and VFR
the rest of the period. Winds will be mainly light.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Winter Weather Advisory until 4 AM CST Saturday for Audrain MO-
Knox MO-Lewis MO-Marion MO-Monroe MO-Pike MO-Ralls MO-
Shelby MO.
IL...Winter Weather Advisory until 4 AM CST Saturday for Adams IL-
Brown IL-Greene IL-Macoupin IL-Montgomery IL-Pike IL.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
533 PM CST Fri Feb 24 2023
.DISCUSSION...(This evening through Friday)
Issued at 245 PM CST Fri Feb 24 2023
KEY MESSAGES:
- Quick burst of light snow this evening with around an inch of
accumulation likely.
- Widespread mixed precipitation with some accumulation of ice and
snow late Sunday night through Monday.
Mid level clouds have increased this afternoon across much of the
area which has slowed warming a bit. Temperatures are in the single
digits above and below zero, coldest west where clouds moved in
earlier. The clouds have produced a few flurries across southwestern
Minnesota, but the extent of dry air below 7 kft should limit it to
just that this afternoon. The next round of light snow this evening
will be associated with a short wave over the Colorado Rockies this
afternoon. This short wave will zip east northeast over the large mid
level ridge centered over the southeast and track overhead late this
evening. Snow will begin to blossom across western Minnesota shortly
after 6 or 7 PM and then expand eastward through the rest of the
evening. Snow ratios will be high (18-19:1) due to a combination of
light surface winds and a DGZ depth of about 11 kft. The snow won`t
last long, maybe about 3 hours, with each hour picking up a hundredth
or two of liquid equivalent. This should equate to about an inch of
snow, a pretty light event.
The weekend will be quiet and milder with a ridge building in. A
strong short wave over the Desert Southwest will begin advancing into
the southern Rockies and southern Plains Sunday, then northeast into
the mid/upper Mississippi Valley by early Monday. This system will
remain compact, but will be accompanied by a lot of moisture.
Precipitation will overspread the area from the south late Sunday
night. Surface temperatures below freezing and mild air aloft will
make for an initial round of freezing rain in most areas following
the onset of the precipitation, except perhaps across southern MN
where temps may remain above freezing. The highest risk for any
accumulation will be across central MN and western WI where temps
could be in the 20s. As the system and even deeper moisture arrives
early Monday, surface temps should rise a couple degrees above
freezing and end any further icing. However, temperatures aloft will
be cooling and some snow will begin mixing in late Monday morning
and afternoon as the system`s center tracks into southern Wisconsin.
By the time this happens, most of the remaining precip will be over
northwest Wisconsin, which is where the best accumulating snow
potential resides. Total QPF spread amongst the guidance is still
quite large, especially on the western edge. This is due to a tight
gradient between a colder and drier polar airmass to the west and a
Gulf moisture-laden airmass to the east. Parts of Wisconsin may reach
1.5 inch QPF while western MN may not see much, if any. Therefore,
amounts will be heavily dependent on the track and some adjustments
will be needed going forward.
The active pattern will continue through next week. Another system
should eject eastward across the northern Plains midweek and bring
another round of light snow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 526 PM CST Fri Feb 24 2023
Minimal changes were made to going TAFs for the light snowfall
starting to build across the area. This will be a quick hitting wave
of snow and will be mostly gone by 9z. Also continued to be more
aggressive with clearing out the skies behind this wave than what the
LAV has, though the HRRR shows things clearing out even faster than
what we have. Not many issues for Sat, with S to SW winds increasing
during the day under mostly sunny skies.
KMSP...Model agreements is pretty strong that we`ll see our highest
snow rates between 3z and 6z. We look to get a quick inch of snow
out of this wave.
/OUTLOOK FOR KMSP/
Sun...VFR. Wind SE 5-10 kts.
Mon...MVFR/IFR with FZRA/RA/SN mix likely. Winds N-NW 10-15 kts.
Tue...VFR. Winds W 5 kts becoming S.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...Borghoff
AVIATION...MPG
Area Forecast Discussion
National Weather Service Marquette MI
1047 PM EST Fri Feb 24 2023
.SHORT TERM...(Through Tonight)
Issued at 308 PM EST FRI FEB 24 2023
Under 850mb temps around -21C per latest RAP analysis, light LES
continues off of Lake Superior, but with falling inversion and the
negative impact of daytime heating, the LES is also diminishing and
is very light now. Winds have also been backing today as a large
high pres area shifts into the western Great Lakes region. As a
result, LES has ended to the s of Silver City, and the LES is
shifting eastward over the eastern fcst area. Otherwise, a mix of
clouds and sun is the rule away from the LES, but there is
increasing sun being noted where backing winds are cutting of the
moisture from the lake.
Into the evening, backing winds will continue to shift the
diminishing LES. All of it should be offshore of Upper MI by
midnight at the latest. Attention then turns to a weak shortwave
moving from the Dakotas to the Great Lakes. Models are in excellent
agreement showing this wave bringing a 3-4hr period of -sn across
the area overnight under weak isentropic ascent/deep layer forcing.
Consensus of guidance is for qpf ranging from 0.03 to 0.1 inches. So
a dusting to 2 inches. Winds may have just a enough of a southerly
component off of Lake MI for some brief/weak enhancement into the
eastern fcst area. So, that area has the best chc of seeing
accumulations in the 1-2 inch range. As for temps, looks like there
may be a window of mostly clear skies in areas where stratocu clears
out and before clouds arrive in association with shortwave. Leaned
on the bias corrected CMC models which show temps falling just blo
0F across a swath from roughly Ontonagon County to Luce County.
Given a period of calm/near calm wind, if skies are mostly clear for
very long, temps could easily fall to or blo -10F. Temps will then
gradually rise overnight.
.LONG TERM...(Saturday through Friday)
Issued at 342 PM EST FRI FEB 24 2023
Key Messages:
-WSW lake effect becoming lighter through Saturday
-Weak ridge Sunday keeps things dry
-Next impactful system Monday
-Active pattern continues, daily highs around freezing
Following tropa Saturday, surface layer winds become WSWerly and
while temperatures aloft start cool enough to support LES, the CAMs
keep snowfall confined to the Keweenaw and becoming lighter
throughout the day as temperatures at 850mb warm to around -10 C.
All remaining showers should cease Sunday as a weak ridge (1015 mb
by 00Z EPS ensemble mean) moves over the UP vicinity. Clearing skies
should allow a wider diurnal range with Sunday`s highs expected to
climb to above freezing in some spots, yet the Monday morning low
is expected to be below 20 throughout the UP.
Attention quickly turns to the next potentially impactful system
Monday. Sunday, a deep trough will begin ejecting out of the desert
southwest, arriving in the Great Lakes Monday afternoon. Low track
and depth will be key factors for the forecast details. 00Z Euro low
tracks generally around Chicago to Lake Erie Monday evening and
has been trending a bit faster each run. The 00Z GEFS is a bit
more northerly, with a Milwaukee to the Saginaw Bay track for the
same time period and has been very consistent run to run, only
slightly tracking north the last few runs. Within ensembles, the
depth of the low is somewhat variable, with deeper lows having a
more expansive precip shield, though there`s enough variation in
solutions that it`s less predictive and more "keep an eye on
this". QPF will be boosted by an apparent Gulf connection shown in
the NAEFS IVT climo percentile map. A wide range of snowfall
solutions is possible, with both the Euro and GEFS plumes showing
fairly equal spacing of ensemble members from an inch to a foot of
snow accumulation with fairly little clustering. One complicating
factor will be the presence of an Alberta Clipper shortwave
immediately following the trough, and depending on if the lows are
close enough to phase and interact, model solutions could get
complex in a hurry. NBM Ptypes also are a bit complex as some
solutions (though not all) like the NAM introduce a warm nose in
the soundings. Even if the surface temps support frozen precip,
some of it may fall as sleet, and a few areas of freezing rain
can`t be ruled out either. Confidence in a freezing rain solution
is low as the depth of the surface cold air should be deep enough
in most areas for a complete refreeze of any melted particles,
though left at least mentionable fzra in the grids as the NBM
ptype is insistent that it will be present even if forecaster
confidence is low.
Once the trough/clipper pass Tuesday, model solutions vastly differ
on details, but agree on the general pattern being busy, with
shortwave after shortwave after shortwave arriving in some pattern.
Most will be relatively low-amplitude clippers and the like, but
while timing and location vastly differ, each of the deterministic
models eject a deep trough from the southwest to the Great Lakes
near the end of the week. NBM temperature trends appear to be
slightly above seasonal normals, with highs around the freezing mark
through much of the week. This will act to reduce the SLRs of
whatever snow comes through, or even introduce other precip types,
in a stark contrast to the "super fluff" from the past snow system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1047 PM EST FRI FEB 24 2023
VFR conditions will hold steady at all TAF sites over the next
several hours. However, a disturbance will move in and bring snow
showers and MVFR/IFR conditions through daybreak. After that, look
for improvement to VFR again, except at CMX where MVFR will persist.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 342 PM EST FRI FEB 24 2023
Winds across the lake remain below 20 knots until overnight tonight
into Saturday, when SWerly gusts increase to 20 to 25 knots across
the lake and up to 30 knots Saturday afternoon and evening in the
west half. As a high moves over the lake Sunday, winds fall below 20
knots in the afternoon. As a low approaches from the southwest
overnight Sunday into Monday, winds pick back up again, with
easterly gusts Monday morning of 25 to 30 knots across the lake.
Some brief gales are expected over the east half Monday afternoon
before the low passes completely and winds fall below 20 knots
overnight into Tuesday. Werly winds will gust to 25 knots across the
lake Tuesday before falling below 20 knots at night. Gusts exceeding
20 knots are possible again late in the week as another trough is
expected to pass, but uncertainty is high in the details late in the
week.
Other marine hazards include 8-10 foot waves Monday afternoon across
the central and east and heavy freezing spray in the west Saturday
night.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...GS
AVIATION...TDUD
MARINE...GS