Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/16/25
Area Forecast Discussion
National Weather Service La Crosse WI
947 PM CST Wed Jan 15 2025
.KEY MESSAGES...
- Snow showers will move through the region late this afternoon
through tonight. The highest chances (60-90%) for snow showers
will be along and north of I-94 with lower probabilities
(20-50%) elsewhere. Some patchy freezing drizzle cannot be
ruled out (10-20% chance) late this evening and overnight.
- Warmer temperatures move in for Thursday and Friday with highs
in the 30s and 40s areawide.
- Bitterly cold air moves into the region this weekend and to
start next week with very high probabilities (60-90% chance)
for morning wind chills of -25F and colder areawide.
&&
.DISCUSSION...
Issued at 158 PM CST Wed Jan 15 2025
Rest of Today - Tonight: Snow Showers Move Through Area
Surface analysis this afternoon depicts our area being subjected to
surface southwesterly flow and an approaching warm front to our
east. In the upper-levels, GOES-16 water vapor imagery and RAP 500mb
heights show northwesterly flow aloft with a shortwave progressing
into the Great Lakes region. As we continue later this afternoon,
low-level isentropic ascent ahead of this boundary coupled with warm
air advection will continue to propel ongoing snow showers across
central Minnesota into our local area. Initially, abundant low-level
forcing appears in play to push saturation well into the dendritic
growth zone giving high confidence that the initial p-type mode will
be snow late this afternoon and into this evening. Accumulations
generally appear fairly minimal with fairly low (10-30%)
probabilities for over 0.5" in the 15.12z HREF south of I-94,
assuming a near climatology SLR. Probabilities for over 0.5" are
decently higher north of I-94 where the CAMs indicate more shower
activity with values generally of 50 to 80%.
The more tricky part of the forecast as we get later into the
evening will be as low-level lift lessens and if a period of
freezing drizzle will be possible late this evening and overnight.
Based on RAP/HRRR soundings, lessening saturation in the dendritic
growth zone can be noted at sites such as La Crosse and Eau Claire.
However, the issue in this case is relatively steep lapse rates atop
this saturated layer that may enable some convection into the DGZ
regardless. As a result, confidence is very low if freezing drizzle
will be able to manifest in this environment. However given some
fairly dry RH fields south of I-94 across some of the CAMs in the
DGZ, have opted to mention some slight chances (10-20%) for freezing
drizzle from 03z to 09z to account for this lower-end possibility.
Thursday - Friday: Above Normal Temperatures
Starting tomorrow, upper-level ridging and returning southwesterly
flow at the surface will aid in trending our temperatures above
normal for Thursday with highs in the upper 20s to middle 30s. As
the ridge axis moves overhead for Friday, this will likely be the
warmest day with median high temperatures in the grand ensemble
(GEFS/EC/Canadian ensemble) anywhere from the middle 30s to lower
40s for Friday afternoon. This is further supported by the 15.00z EC
Extreme Forecast Index which indicates a 60 to 80% probability of
exceeding model climatology for high temperatures on Friday.
Certainly Friday looks like the best day in the forecast period to
get outside, especially when considering the very cold temperatures
moving into our area starting this weekend.
Saturday - Tuesday: Very Cold Air Moves In
By the time Saturday approaches, a robust upper-level trough will
begin to swing into the region with an arctic front pushing through
the area during the pre-dawn hours on Saturday. As strong
northwesterly flow advects arctic air into the region, temperatures
will fall through the teens and single digits through the day on
Saturday and below zero overnight Saturday night. As we head into
Sunday morning, the main axis of cold air begins to move overhead
with 850mb temperatures falling to around -30C as shown in both the
15.12z GFS/EC. This will instigate a very cold period from Sunday
into Tuesday with this airmass directly overhead. Probabilities
during this period already are very high (60-90%) for morning wind
chills under -25F during this period (20-60% chance for -35F!) in
the recent grand ensemble (GEFS/EC/Canadian ensemble). Additionally,
the daytime hours may very well still be hazardously cold with the
grand ensemble (GEFS/EC/Canadian ensemble) having modest
probabilities for sub -25F wind chills even during the daytime hours
on these days with afternoon high air temperatures not reaching 0 in
some locations. Overall, seems like the coldest period we have seen
thus far this winter with confidence increasing for hazardously cold
temperatures.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1000 PM CST Wed Jan 15 2025
As has been the pattern tonight, a drier low levels has resulted
in backing off of MVFR ceiling onset at the 16.06Z TAF
issuance. Immediate concern will be a clockwise wind shift from
the southwest at 16.04Z to west-northwest over the next few
hours. Associated front is moving from west to east. Current
(16.04Z) wind shift seen in surface observations from southwest
Minnesota through eastern Minnesota.
Have delayed MVFR ceiling onset until the morning hours as low
level cold air advection saturates the lowest levels from north
to south. Stronger, albeit still low, confidence on low level
dry air between high resolution models has caused said delay.
Extent and timing remain low confidence.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor
AVIATION...JAR
Area Forecast Discussion
National Weather Service El Paso TX/Santa Teresa NM
426 PM MST Wed Jan 15 2025
...New AVIATION...
.KEY MESSAGES...
Updated at 423 PM MST Wed Jan 15 2025
- A Pacific storm brings gusty winds and patchy blowing dust for
Friday.
- Several surges of cold air begin moving in late on Saturday
with next week`s temperatures back to well below normal.
&&
.DISCUSSION...
Issued at 220 PM MST Wed Jan 15 2025
Fairly quiet, seasonal weather is in place across the Borderland,
and that will remain the case through tomorrow. Southern NM and
Far West TX are sitting beneath a s/w ridge, sandwiched between a
long wave trough covering the eastern half of the CONUS and a Rex
Block over the Pacific and West Coast. The low off the Baja Coast
will translate toward the ENE, coming ashore by mid-day Thursday.
High clouds will filter in from the south, but tomorrow`s weather
will remain quiet and a little warmer than today. The trough will
open up and continue its ENE trek across NM by Friday afternoon,
placing its H500 jet across the International Border and into
Mexico. At the surface, a broad area of low pressure, less than
1000 mb, will form over the TX Panhandle. The pattern will make
for a breezy to low-end windy day with blowing dust along and
south of I-10 the main concern. Wind gusts look to range 35-45 MPH
with some higher gusts approaching or briefly exceeding 50 MPH for
our higher elevations and east slopes. I will hold off on any
advisories on this shift as probabilities to exceed 50 MPH gusts
are only about 50%.
As the system slips through the region it will bring a slight
chance of precipitation to the Gila, but it is largely expected
to be a dry passage. It should be noted, however, the HRRR is an
aggressive outlier with the exit region / warm-conveyor belt of
the jet and produces light to moderate rain early Friday morning,
especially toward the International Border and into our Texas
counties. This solution appears to be an outlier, however.
The system exits quickly Saturday morning. East slope areas will
still be somewhat breezy to start the day, but winds will decrease
by afternoon. Temperatures will be a few degrees cooler than
Friday but will still be near or just above normal. During the
day, a s/w will be dropping south along the Front Range of the
Rockies while the Pacific Ridge continues to amplify. This pattern
will set the stage for another arctic outbreak, ushered southward
by the aforementioned s/w. This Arctic air will make its first
push through our CWA late Saturday into Sunday, setting highs
back by 10 to 15 degrees. We keep the easterly tap on Monday with
cooler air continuing to push in. Latest guidance has warmed
temperatures a tad for Monday, however. By Tuesday, another s/w
will drop south along the Front Range of the Rockies. It will push
more arctic air into the CWA for Tuesday. Highs will struggle to
get out of the 30s. Morning lows during this period will be in the
teens and 20s, with wind chills into the lower teens and single
digits. Mountains will see wind chills below zero. Cold weather
advisories will probably be needed. Forecast guidance continues to
struggle with how cold it will get, but typically the colder side
of guidance tends to be correct. This arctic outbreak looks to be
as cold, if not colder than the one earlier this month.
In terms of snow, probabilities still look pretty low except for
our mountains. Cluster analysis and a look at ensemble members
favor a solution where Tuesday`s s/w comes through with little
amplitude and thus little dynamics and moisture. NBM had POPs
15-20 percent, but I lowered them for the lowlands. I kept the
POPs in the mountains given upslope flow and the tendency for
arctic air to squeeze moisture out of the air. Either way, any
snowfall impacts look minor to none.
&&
.AVIATION...
(00Z TAFS)
Issued at 423 PM MST Wed Jan 15 2025
VFR conditions across the entire regions, including all terminals,
through the period. Skies varying from SKC to BKN250. Winds NW
6-12kts through 02z...then diminishing to 2-6kts and turning
toward more northerly.
&&
.FIRE WEATHER...
Issued at 220 PM MST Wed Jan 15 2025
The forecast will feature minimal to no fire concerns.
Temperatures through Saturday will be seasonal or just above
normal with afternoon RH values in the upper teens and into the
lower 20s. Winds will be light for Thursday but will become breezy
for Friday. Saturday will feature quiet conditions, but by Sunday
we begin a cooling trend with the arrival of arctic air. Venting
will be poor to fair for Thursday but will generally be excellent
on Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 35 62 42 62 / 0 0 0 0
Sierra Blanca 32 60 38 57 / 0 0 0 10
Las Cruces 29 58 35 59 / 0 0 0 0
Alamogordo 24 56 29 58 / 0 0 0 0
Cloudcroft 20 43 24 35 / 0 0 0 0
Truth or Consequences 25 53 31 58 / 0 0 0 0
Silver City 29 54 29 47 / 0 0 10 0
Deming 29 58 32 57 / 0 0 0 0
Lordsburg 27 59 28 54 / 0 0 10 0
West El Paso Metro 36 60 41 59 / 0 0 0 0
Dell City 27 59 34 60 / 0 0 0 0
Fort Hancock 32 66 37 63 / 0 0 0 10
Loma Linda 34 56 38 52 / 0 0 0 0
Fabens 34 64 39 62 / 0 0 0 0
Santa Teresa 31 58 37 57 / 0 0 0 0
White Sands HQ 34 58 40 59 / 0 0 0 0
Jornada Range 24 56 28 59 / 0 0 0 0
Hatch 24 58 29 60 / 0 0 0 0
Columbus 32 59 37 58 / 0 0 0 0
Orogrande 27 57 32 57 / 0 0 0 0
Mayhill 23 58 32 47 / 0 0 0 0
Mescalero 21 51 27 45 / 0 0 0 10
Timberon 20 51 24 45 / 0 0 0 0
Winston 17 51 21 51 / 0 0 0 0
Hillsboro 27 55 31 56 / 0 0 0 0
Spaceport 22 55 25 59 / 0 0 0 0
Lake Roberts 26 56 27 47 / 0 0 10 10
Hurley 24 55 28 50 / 0 0 0 0
Cliff 15 64 17 57 / 0 0 10 0
Mule Creek 26 58 28 50 / 0 0 20 10
Faywood 29 54 32 51 / 0 0 0 0
Animas 26 61 29 58 / 0 0 10 10
Hachita 27 58 29 57 / 0 0 0 0
Antelope Wells 29 59 35 57 / 0 0 10 10
Cloverdale 33 59 36 52 / 0 0 10 10
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...None.
&&
$$
FORECASTER...14-Bird
Area Forecast Discussion
National Weather Service Indianapolis IN
952 PM EST Wed Jan 15 2025
.KEY MESSAGES...
- Scattered light snow showers along and northeast of the I-74
corridor expected early Thursday morning. Snow accumulations under
an inch.
- Warm up Friday with rain Friday evening changing to snow
overnight.
- Bitterly cold air is expected Sunday through the middle of next
week with multiple nights of subzero lows likely
&&
.FORECAST UPDATE...
Issued at 952 PM EST Wed Jan 15 2025
Another cold night is already upon central Indiana, albeit much
closer to seasonable normals than last night`s subzero readings. An
overall weak disturbance approaching from the northwest will
continue to promote south-southwesterly breezes and thickening
clouds for most of the region. This will serve to hold temperatures
steady in the 15-20F range for most locations through the late
evening...before a modest warming occurs towards daybreak. Have
nudged up tonight`s minimums for several zones, yet kept values in
the low teens for far southwestern counties where clouds have been
slower to thicken. Wind chills in the single digits will rise
through pre-dawn hours to 10-15 degrees for a majority of the region.
Model divergence on tonight`s snow shower threat includes HRRR
trying to bring snow showers to southwestern Indiana, while latest
NAM runs hold any measurable precipitation north of the CWA despite
a H500 vort max slicing down the I-74 corridor towards the middle of
the state. Therefore held with slight chance/low-chances of snow
showers along/north of I-74...which follows with upstream echoes so
far maintaining themselves through the Quad Cities area. Timing
should be only a few hours for any given location, mainly after 6Z.
&&
.SHORT TERM (This evening through Thursday)...
Issued at 259 PM EST Wed Jan 15 2025
An arctic airmass has settled over the state today with temperatures
struggling to rise from the sub-zero lows into the teens this
afternoon.
Focus shifts to the next weak system approaching the area from the
northwest tonight that could bring clouds and scattered snow showers
to Central and North Central Indiana. A positively tilted mid level
trough and an associated jet streak drop southeast from Canada into
the Ohio Valley and Great Lakes region. The parent low is all the
way up near the Hudson Bay with the main source of any moisture
coming from the Pacific or Great Lakes. The antecedent airmass is
drier than what guidance depicts based on observation today, so will
have to take this into account as well as the system does not have a
ton of moisture to work with. Forecast soundings and BUFKIT cross
sections from short term models show a brief period when the trough
axis swings through where modest lift aligns with enough saturation
through the lower levels and DGZ to support isolated to scattered
snow showers. Best moisture and forcing for ascent appear to be
along and northeast of the I-74 corridor within the 2am - 9am
timeframe before much drier air moves in aloft. Any snow amounts
should be light and under a half inch in locations that do see a
snow shower. Areas north and east of the Indianapolis Metro have the
highest likelihood of picking up minor accumulations as moisture
streaming in off Lake Michigan may enhance snow shower activity
locally.
A tightening surface pressure gradient and steepening low level
lapse rates during the day on Thursday should result in increase
west northwesterly winds upwards of 20-25+ mph during the late
morning and afternoon hours. Mixing and slight "warm" air advection
aloft as the arctic airmass retreats should yield highs near and
just above the freezing mark tomorrow afternoon; however breezy
conditions will keep wind chill in the low to mid 20s.
&&
.LONG TERM (Thursday night through Wednesday)...
Issued at 259 PM EST Wed Jan 15 2025
Transient mean ridging will pass on Friday bringing a temperature
increase to warmer conditions than we have experienced since the
2nd. There is some uncertainty on temperatures from the effects of
residual snow cover albedo. So we won`t go as high as
statistical/MOS guidance. Stratus may be present in the morning but
should clear by late morning or midday as MSLP pattern changes.
A southern stream wave should force a precipitation event Friday
night with most ensemble members in the 0.25-0.50 range. There
should be enough warm advection for a deep enough above freezing
layer for all rain at precipitation onset. As cold advection starts
later in the evening/overnight, thermal profiles will become
favorable for snow. Timing of sufficiently cold onset vs QPF is
unclear at the moment, but it does appear that enough cold and
precipitation will overlap for some accumulation, especially across
the northwest half. More details as the event nears.
Over the weekend a northern stream wave will phase the southern
stream and result in a deep highly anomalous trough supporting
dislodging of Arctic air into our region. The coldest temperatures
of the season are expected with highs Sunday in the teens, and
single digits Monday. MSLP pattern isn`t the best for optimal
radiative conditions, but the magnitude of the Arctic air mass
should be enough for sub-zero overnight lows during this period.
Some modification may occur by the latter half of next week as the
anomalous trough moves east. Even then, residual Arctic air mass and
modest at best warm advection will keep temperatures 10-15 degrees
below normal.
The Day 8-14 period looks to see some moderation but still colder
than normal given a persistent eastern CONUS trough. Some minor
precipitation chances may occur given the progressive pattern with
minor shortwaves indicated in medium-range guidance.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 635 PM EST Wed Jan 15 2025
Impacts:
- Low chances -SHSN late tonight within 06Z-11Z
- MVFR ceilings starting during 08Z-15Z Thursday...continuing into
at least early evening Thursday
- Gusty winds to 20-25KT during daytime hours Thursday
Discussion:
Ceilings will fall through VFR levels this evening as an overall
weak disturbance approaches from the northwest. MVFR CIGs are
expected over at least KIND/KLAF by 09Z tonight...with mainly low-
VFR expected at KHUF/KBMG through daybreak. -SHSN may drop VIS to
MVFR at KIND/KLAF late tonight through 12Z, with confidence too low
to include -SHSN at KHUF/KBMG. MVFR CIGs to continue Thursday...
although low-VFR should return at KIND Thursday evening.
Winds will slowly veer through Thursday afternoon. South-southwest
to southwesterly flow this evening will be sustained to mainly 10KT
or less. Late tonight southwesterly winds will gust up to 18-20KT.
Thursday`s overall westerly to west-northwesterly winds will be
sustained at generally 9-14KT, with gusts to 20-25KT through most of
the day.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None. &&
$$
UPDATE...AGM
SHORT TERM...CM
LONG TERM...BRB
AVIATION...AGM
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
844 PM CST Wed Jan 15 2025
.KEY MESSAGES...
- Scattered gusty snow showers may lead to local slick spots
mid-evening and overnight.
- Friday will be blustery with above normal temps, then the
coldest air mass of the season thus far will arrive Sunday and
linger through mid next week with dangerously low wind chills
possible at times.
- Rain Friday evening changing to wet snow before ending early
Saturday, primarily for areas southeast of I-55.
- During the cold snap, most if not all of the precip will be lake
effect snow, potentially including northeast Porter Co. at times.
&&
.UPDATE...
Issued at 844 PM CST Wed Jan 15 2025
Other than a bit of very minor fine-tuning of the timing, no
real changes made to the forecast for the snow showers tonight.
First band seen on radar moving across northwestern portions of
CWA is encountering dry low levels and mainly producing virga
to a few flurries. Additional echoes upstream across southern WI
will likely produce scattered snow showers across the area from
late this evening into the first half or so of the overnight
hours. Accumulations of a coating to a half inch still look
right on target.
One change to the forecast for tonight was to remove mention of
freezing drizzle and flurries for late tonight and Thursday
morning. Upstream observations show very little stratus and what
stratus there is remains high based and unlikely to produce
drizzle. Vast majority of the ceiling guidance suggests that
cloud bases will remain mostly VFR (>3kft) late tonight into
Thursday morning, which is what upstream observations also show.
Finally, the latest forecast soundings from the HRRR and RAP
both show mean RH values less than 85% in the 0-1km layer with
low level subsidence. Freezing drizzle is very challenging to
forecast, but struggling to find much support for FZDZ, except
in the NAM which is notorious for being too moist/saturated in
the boundary layer in the winter.
Did nudge temps upward a bit overnight, especially over the
northwestern CWA where lack of snow cover and strong southwest
winds and resultant warm air advection likely results in slowly
rising temps tonight. By sunrise, temperatures should warm into
the low to mid 20s, warmest over the northwestern CWA. Upstream
dewpoints are mostly in the uppper single digits to mid teens,
so that should result in T/TD depressions of at least 5-8F by
morning, which also supports the notion that freezing drizzle is
unlikely.
- Izzi
&&
.DISCUSSION...
Issued at 246 PM CST Wed Jan 15 2025
Through Thursday Night:
An amplifying mid to upper-level trough on the northeast
periphery of a stacked strong jet will dig southeastward across
the western Great Lakes through tonight. Robust deep forcing
within the left-exit of the mid to upper-level jet and a ribbon
of low-level WAA/isentropic ascent will feed into seasonably
steep mid-level lapse rates to produce scattered bursts of gusty
snow showers across northern Illinois and northwest Indiana
mid-evening through the early overnight hours. Upstream
observations show that a broken axis of potent snow showers is
already present across central Minnesota early this afternoon,
further supporting tonight`s expectations. While the overall
coverage of the snow showers is less certain, the strongest snow
showers will be capable of producing quick accumulations of up
to a half inch along with SW/W gusts in excess of 25 mph. By the
pre-dawn hours, accumulations will likely range from a trace to
a couple localized narrow bands up to around 1" across northern
Illinois (particularly northeast Illinois) and northwest
Indiana.
With the loss of deeper moisture behind the mid/upper-level
trough, cloud ice will become less prevalent in the lingering
low-level stratus. Though low-level ascent will be waning with
time from west to east, patchy freezing drizzle and/or light
poor-quality snow/flurries may proceed the snow showers for
several hours. This includes much of northeast Illinois through
around mid-morning. Overall, sporadic impacts are possible due
to locally slippery spots from the snow showers and freezing
drizzle.
Temps should warm to around the freezing mark for several hours
late morning through the afternoon Thursday as stratus persists
across the area. Eventually, a gradually lowering inversion in
response to a passing mid-level ridge will erode the remaining
stratus from southwest to northeast late Thursday night into
Friday morning.
Kluber
Friday through Wednesday:
Deep 985-990 mb surface low pressure will pass north of Lake
Superior on Friday, with the associated cold frontal trough
approaching from the midwest. A tight pressure gradient between
low pressure to our north and west and expansive high pressure to
the southeast amidst a robust low-level jet aloft will set the
stage for blustery south-southwesterly warm air advection. Most of
the guidance scours out any lingering low clouds early in the day,
but this isn`t a sure thing. In addition, the existing snow cover
over the southeast 1/2 to 2/3 or so of the CWA (and well south of
there) casts uncertainty on how warm temps will get given that
the brisk southerly flow will be occurring over expansive snow cover.
There should be a northwest (milder) to southeast high temp
gradient over the area, possibly sharper in reality than we can
depict at this range. Our afternoon forecast officially shows
upper 30s to lower 40s near and northwest of I-55 (mildest in
northwest IL) and mid 30s southeast of I-55. Lower mixing depths
where temps stay cooler should keep wind gusts in check a bit,
though it`ll be blustery areawide with gusts up to 30-35 mph.
Banded precip will blossom in the frontal trough Friday evening
as cold air advection ensues aloft, primarily southeast of I-55.
Expect a sharp gradient on the northwest edge of the precip
shield, which will be further refined in subsequent updates. An
initially above freezing profile will result in the precip
starting as rain, though for areas that do receive precip, ptype
should mix with and then change to wet snow before ending in the
pre-dawn hours of Saturday. A slushy coating of snow is possible
on colder surfaces, however mostly above freezing air temps
will likely limit travel impacts.
Temperatures will primarily flat-line Saturday (low 20s NW to
near 30F southeast) amidst blustery north-northwest winds
gusting up to 30 mph and lingering post-frontal stratus, with
perhaps some spotty flurries. PM wind chills will be back down
in the single digits and lower teens. Lake effect parameters
will be somewhat marginal on Saturday, though sufficient to hold
onto lower chance (~30%) PoPs into northeast Porter County.
As cross-Polar flow takes hold Saturday night and onward, a
truly Arctic air mass will arrive with 850 mb temps bottoming
out as low as -25 to -30C in the Sunday night-Tuesday morning
timeframe. The lack of snow cover in parts of our area (which
will likely see some further erosion on Friday) and upstream
makes it a bit uncertain exactly how cold temps and wind chills
may get in this stretch. The lowest temps will occur Sunday
night-Monday AM and Monday night-Tuesday AM when sub-zero lows
are forecast area wide along with minimum wind chills ranging
from -15 to -25F. Daytime high temps will likely be held into
the positive single digits for the northwest half of the area on
Sunday and area-wide on Monday-Tuesday. Some moderation back to
merely below normal will occur by next Wednesday.
The northwest to westerly flow pattern during the cold snap will
likely relegate precip chances to persistent lake effect snow
for the favored snow belts, possibly clipping northeast Porter
County at times. While we certainly can`t rule out subtle low
amplitude impulses being able to wring out light snow or
flurries in such a cold pattern, the main message is to prepare
for the at times dangerously cold conditions.
Castro
&&
.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 602 PM CST Wed Jan 15 2025
- A 2-3 hour period of snow showers (occasional IFR VSBY) is
expected late this evening into the early portion of the
overnight hours.
A fast moving weather system will move across the region tonight
and result in a period of snow showers across the terminals late
this evening into the early portions of the overnight hours. In
the more robust snow showers visibility will likely drop to IFR
at times. Snow accumulations around a half inch are expected
during this period of snow showers.
Upstream observation and satellite trends show a rather quick
transition to VFR and even some clearing a couple of hours after
the snow showers pass. Guidance is hanging onto MVFR CIGS after
the snow showers and certainly climo would favor some stratus
lingering in the wake of the snow showers, so have maintained
MVFR CIGS overnight and through the day Thursday. If stratus
doesn`t materialize as forecast, then later TAFS will likely
adjust to an earlier transition to VFR.
- Izzi
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 3 PM CST Thursday for Winthrop
Harbor IL to Gary IN.
Small Craft Advisory until 9 PM CST Thursday for Gary to Burns
Harbor IN-Burns Harbor to Michigan City IN.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Melbourne FL
855 PM EST Wed Jan 15 2025
...New UPDATE...
.KEY MESSAGES...
Issued at 300 PM EST Wed Jan 15 2025
- Cooler than normal conditions through Friday with the coldest
temperatures forecast Friday morning.
- An active pattern returns this weekend with higher rain chances,
breezy conditions, and above normal temperatures.
- Below normal temperatures return early next week behind Sunday`s
cold front.
&&
.UPDATE...
Issued at 855 PM EST Wed Jan 15 2025
Mid to high level clouds will continue to push E/NE across central
Florida overnight. Radar has been showing some light returns with
this cloud deck, but MRMS reflectivity and sfc obs indicate that
most of this continues to not reach the surface due to pockets of
drier air below 500mb. Greatest potential for some limited light
rainfall accumulation will be across north Florida later tonight
into northern Lake and Volusia counties ahead of a passing SW
aloft. However, can`t completely rule out some light sprinkles at
times late tonight farther south. For now have keep mentionable
rain chances, around 20 percent, north of Sanford.
Lows tonight will be near to slightly cooler than normal in the
low to mid 40s across Lake/Volusia counties and upper 40s to low
50s farther south (except mid 50s along coastal Martin County).
These values are near to just below NBM guidance, and not quite
as cool as MOS output, as cloud cover and weakening northerly
winds should help keep temps up a bit tonight.
&&
.PREVIOUS DISCUSSION...
Issued at 300 PM EST Wed Jan 15 2025
Now-Tonight...Mid and high level clouds are streaming west to east
across the Florida Peninsula this afternoon as temperatures slowly
climb into the mid 50s (north) to upper 60s (south). It has also
been a little breezy, with northerly winds gusting 20-25+ mph at
times along the immediate coast. RAP analysis indicates a fairly
tight pressure gradient over the area, but this should unwind
tonight, allowing wind speeds to decrease. Radar returns are very
light at this time, with broken bands of 20dBZ or less traversing
the state. Most of this activity is struggling to reach the
ground, evidenced well by the very dry low levels in this
morning`s XMR sounding.
Another night of below normal temperatures is forecast with the
coldest spots north of I-4 by early Thursday morning. However,
with cloud cover expected to blanket the area, forecast lows are
up to 5 degrees warmer compared to temperatures we experienced
this morning.
Thursday-Friday...Lighter winds and minimal precipitation are
forecast to end the work week, but temperatures will stay below
normal for mid-January. High pressure stays in place during this
timeframe, while northwest 500mb flow on Thursday becomes quasi-
zonal on Friday. A cool start on Thursday gives way to cool
afternoon temperatures, ranging through the 60s areawide. Some
clouds may linger near the Treasure Coast Thursday night into
Friday, but many locations (especially north of I-4) will become
mostly clear. Calm and clear conditions will allow for efficient
radiational cooling to take place, dropping temperatures into the
upper 30s over northern Lake/Volusia counties, with values ranging
through the 40s to low 50s over the remainder of the area. A mostly
clear to partly cloudy sky on Friday will do very little to help
temperatures recover, staying slightly below normal Friday
afternoon.
Saturday-Sunday...A significant warmup and more active pattern
returns to the area this weekend. For those looking to get
outside and take a break from long sleeves and jackets, highs in
the 70s to low 80s are forecast each day. A broad longwave trough
is set to move across the Lower MS Valley and central Gulf Coast
Saturday morning as a warm front lifts north of Florida. As return
flow quickly increases, so does moisture. Anomalously high PW
surge across north-central Florida Saturday afternoon, supporting
an increase in shower activity through the day. Locations near
and north of the Orlando metro to Cape Canaveral look best
situated to receive measurable rainfall Saturday afternoon and
evening. Likely rain chances expand to the remainder of the area
on Sunday as a strong cold front pushes south. Models have swung
back and forth with regard to available MUCAPE on Sunday, but
have decided to include a low chance of thunder Sunday afternoon,
mainly from the Orlando area to points south. Throughout the
weekend, winds will be breezy to gusty at times as the pressure
gradient strengthens ahead of the front. Temperatures plummet
Sunday night into early Monday as colder and drier air dig south.
Next Week (previous)...An active pattern is forecast to continue
into early next week. Models continue to disagree on the exact
setup. However, the bottom line appears to be that shower chances
will continue, though the amount of showers is in question.
Onshore flow looks to develop, producing breezy conditions along
the coast. Temperatures are forecast to remain cool, but nearer to
normal than the previous few weeks.
&&
.MARINE...
Issued at 300 PM EST Wed Jan 15 2025
Winds...Gusty north winds this evening will gradually decrease
tonight, with speeds 10-15 kt expected on Thursday. Northwest
winds briefly increase to 15-20 kt offshore Thursday night,
slackening on Friday to 10 kt or less. Surface flow then shifts to
the south on Saturday, reaching 15-25 kt. Winds veer increasingly
west- southwest by Sunday as a cold front moves across the
waters.
Seas...Waves up to 6 ft in the Gulf Stream remain possible through
tonight before a generally favorable period of boating conditions
Thursday through early Saturday morning. As winds increase
Saturday, seas build (especially offshore) up to 6 ft. Episodes of
poor to hazardous boating conditions will be possible from this
weekend into early next week, mainly in the offshore waters.
&&
.AVIATION...
(00Z TAFs)
Issued at 649 PM EST Wed Jan 15 2025
VFR conditions forecast to continue tonight into Thursday. Higher
cloud deck with cigs at or above 15kft will lower to around 7-9kft
into tonight through Thursday morning. Passing shortwave aloft may
lead to some light rain/sprinkles developing with these clouds
overnight into early Thursday, but MVFR impacts from this activity
look unlikely. Winds will initially be out of the north and
becoming light (5 knots or less) into tonight. An increase in
northerly winds to 7-10 knots is forecast toward daybreak
Thursday, before weakening again into the afternoon and directions
becoming more variable.
&&
.FIRE WEATHER...
Issued at 300 PM EST Wed Jan 15 2025
Near-critical minimum relative humidity values are forecast
through late week, especially on Friday, as drier air builds over
east central Florida. Winds will remain light and variable
(generally less than 10 mph) on Thursday, veering east-northeast
on Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 44 62 40 63 / 20 20 0 0
MCO 49 63 45 67 / 10 10 0 0
MLB 49 64 44 66 / 10 10 0 0
VRB 52 68 47 69 / 10 10 10 10
LEE 45 63 42 67 / 10 10 0 0
SFB 46 64 42 67 / 10 10 0 0
ORL 48 64 44 67 / 10 10 0 0
FPR 51 67 46 69 / 10 10 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
UPDATE...Weitlich
AVIATION...Weitlich
Area Forecast Discussion
National Weather Service Marquette MI
537 PM EST Wed Jan 15 2025
.KEY MESSAGES...
- A clipper low will bring a quick batch of light snow (1-2
inches) for most of the UP this evening through the first half
of the night. Lake effect snow lingers in the west to
northwest wind belts the second half of the night. Another 1-3
in of snow is expected in those wind belts, with lighter
totals mainly of an inch or less across the rest of the UP.
- SW gales of 35-40kts continue the west half of Lake Superior
this afternoon, ending by midnight Thursday.
- Dangerously cold arctic air settles into the area this
weekend into early next week, leading to temperatures
remaining subzero Saturday night through at least Tuesday
morning over interior western Upper Michigan.
- While winds won`t be strong, whiteouts will be common in the areas
affected by northwest flow lake effect snow showers Saturday
through Monday due to the snow being a fine, powdery type
snow. As a result, travel conditions will be very hazardous in
the lake effect snow areas.
- No widespread, significant snowfalls for Upper MI through
next week. Nearly all of the snow that occurs will be lake
effect driven.
&&
.SHORT TERM /THROUGH THURSDAY/...
Issued at 317 PM EST Wed Jan 15 2025
Afternoon RAP analysis and water vapor imagery depict a clipper
system diving southeast into the Upper Great Lakes with associated
isentropic lift kicking off snow showers in central Minnesota. As
the shortwave nears closer to home, these showers will continue
their eastward march into the UP, eventually reaching the far west
this evening before exiting quickly to the east before sunrise
tomorrow morning. Not expecting any heavy snow accumulations with
these passing "system" snow showers tonight as guidance only
suggests light QPF generally <0.1" tied with SLRs in the upper
teens:1, yielding light snow across the UP 1-2" or less through
tonight.
Behind the cold frontal passage early Thursday morning,
winds veer to the northwest and 850mb temperatures above Lake
Superior lower between -10 to -13C, supporting light lake effect
snow for the NW snowbelts. Lake effect snow will be short lived,
however, as a brief period of ridging aloft and drier air works its
way in across the lake Thursday afternoon, lowering inversion
heights and tapering off LES from west to east. Considering light
QPF and fluffier SLRs closer to 20:1, an additional 1-3" is possible
across the Keweenaw and NW snowbelt between Munising and the Soo.
Otherwise, southwest winds overnight will keep temperatures mostly
above 10F tonight, much warmer than the past few nights. High
temperatures tomorrow are expected to remain in the mid to upper
20s, possible closer to or above freezing near Lake Michigan.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 443 PM EST Wed Jan 15 2025
Medium range model guidance is in excellent agreement on a large
scale surge of arctic air into the U.S. this weekend into early next
week. This will be driven by a building ridge over the ne Pacific
that becomes highly amplified northward thru Alaska/nw Canada into
the high Arctic over the weekend, forcing a significantly deepening
trof downstream across central to eastern N America. Negative height
anomalies at 500mb in this trof settle at about 300m (2-2.4 sigma)
over WI and Upper MI Sun night. Thus, the large scale surge of
arctic air southward into the U.S. Over the last 48hrs, ensembles
have slightly lowered 850mb temps in the core of the cold air as it
reaches Upper MI. Median 850mb temps reach -30 to -31C into western
Upper MI for Sun/Mon with Mon likely the coldest day. 850mb temps
that low at this time of year very easily support 2m temps remaining
subzero during the daylight hrs across interior western Upper MI and
likely thru much of central Upper MI as well. Now, with 850mb temps
forecast to be down to -30C or lower, would expect temps during the
daylight hrs over interior western Upper MI to struggle to get above
-10F Sun/Mon, Mon in particular. Once temps fall blo 0F over
interior western Upper MI Sat night, they won`t rise above 0F until
sometime Tue aftn at the earliest. Min temps will range down thru
the negative teens and -20s F away from Lake Superior. Some record
low min and record low max temps may be set across Upper MI with
this arctic outbreak. Homeowners and property managers who have had
issues with water pipes freezing during periods of very cold
conditions should make preparations now. Areas that have very little
snow cover could also become at risk for freezing of water supply
lines early next week as ground frost depths deepen rapidly. As for
pcpn, this pattern will not support any widespread, significant
snowfalls for Upper MI for the remainder of this week and through
all of next week as only a few clipper type waves will generate some
brief periods of -sn. So, snowfall will be almost exclusively lake
effect driven. While the arctic air arriving over the weekend/early
next week will lead to extreme overlake instability, the cold will
also suppress the DGZ toward the sfc or eliminate it altogether,
leading to a fine/powdery type snow (low SLR) that does not
accumulate as efficiently. On the flip side, this type of snow is
highly effective at reducing vis, leading to frequent whiteouts even
with winds not particularly strong/gusty. This type of snow is also
easily kicked up on roads by vehicles, leading to mini whiteouts as
vehicles pass each other. Travel in the areas affected by nw flow
LES Sat thru early next week will be very hazardous due to poor
visibility. From Tue onward, flow across N America deamplifies, but
there will continue to be ridging in the ne Pacific/adjacent N
America forcing troffing in central and eastern N America. The
deamplification will allow for moderation Tue onward, but the
pattern will still support the potential for colder air to at least
graze Upper MI with the passage of clipper type shortwaves. Expect
temps on most days next week to be blo normal.
Beginning Thu night/Fri, a clipper shortwave will track vcnty of the
International Border and will pass across Upper MI Fri night. This
wave will initiate the start of the arctic air surge. WAA/isentropic
ascent will need to overcome drier air. With bulk of guidance
suggesting sufficient saturation occurring deeper into the
retreating colder air where it is easier to achieve, forecast only
reflects mainly chc pops from the Keweenaw into eastern Upper MI,
beginning very late Thu night over the Keweenaw and spreading to the
e quickly Fri morning. Any snow accumulation will be less than 1
inch. Center of pres falls of 6-7mb/3hr passing just n of Upper MI
on Fri will enhance s to sw sfc winds on Fri. Expect gusts of 25 to
35mph. Downsloping near Lake Superior may yield gusts of 40-45mph
for a few hrs from Marquette County eastward per fcst soundings. 180-
190 wind direction is favorable for strong winds in Schoolcraft/Luce
counties as well. High temps on Fri should reach the low/mid 30s F.
Cold front passes Fri night, initiating LES and leading to
progressively colder air flowing into the area thru the weekend on
predominantly nw low-level flow. The increasingly colder air
surrounding the lake will progressively strengthen lake induced
thermal troffing, leading to winds developing an offshore component.
This will be more notable off of nw WI, off of Marquette County and
off of Ontario along the e side of Lake Superior. This will favor
enhanced convergence from n of Ironwood into Ontonagon/southern
Houghton counties and also into Alger/Luce counties. Expect LES to
be most persistent/heavier in those areas. However, by later Sat and
thru Mon, the cold will suppress the DGZ toward near the sfc or
eliminate it altogether, leading to a fine/powdery type snow that
does not accumulate as efficiently as typical LES. Initial thoughts
are that snow accumulations will end up in a general 1-3 to isold 4-
5 inches/12hr range. Bigger issue will be whiteouts as this type of
snow is highly efficient at reducing visibility and is easily blown
around. Winds will be stronger on Sat after fropa, but during the
coldest period Sun/Mon, winds won`t be particularly strong, gusting
to 25 to at times 30mph near the Lake Superior shore and Keweenaw
and up to around 20mph elsewhere. Even so, the fine/powdery snow
will be easily lofted by these winds to further reduce the already
poor vis from the falling snow. As for temps, max temps in this fcst
issuance are probably a bit on the high side for Sun/Mon given how
low the 850mb temps will be. It`s quite plausible that high temps
will struggle to get above -10F over much of the interior w on
Sun/Mon, Mon in particular. Much of the fcst area may remain blo 0F
both days. Fortunately, the winds won`t be strong to really drive
wind chills down. Nonetheless, the cold will be dangerous, and
expect conditions to warrant cold weather advisories and possibly
extreme cold warnings across the area. Extreme cold warning criteria
are air temps or wind chill -35 or lower over interior western Upper
MI and -30 or lower elsewhere.
Wind begin to back westerly Mon night/Tue with onset of waa,
shifting LES to mainly the Keweenaw over the w and closer to shore
over the e. Clipper type shortwave will pass at some point later
Tue/Wed to provide a chc of -sn. High temps will be back to the
teens F on Wed.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 537 PM EST Wed Jan 15 2025
Clipper system snow will move through the area tonight and will take
the VFR conditions down to IFR as it moves through at all sites.
MVFR conditions will reutrn to all sites Thu afternoon.
&&
.MARINE...
Issued at 443 PM EST Wed Jan 15 2025
A couple of passing clippers will result in a strong pressure
gradient over the lake at times in this period, followed by
deepening arctic cold this weekend and early next week.
Ongoing sw 35-40kt gales over the w half of Lake Superior will fall
back to 30kt tonight as winds shift w to nw. Expect winds up to 30kt
over the e with a few gale force gusts possible during the evening.
The nw winds will increase across the e half of Lake Superior on Thu
morning. Expect gale gusts to 35kt for a time morning thru early
aftn. Probability of gales is 40-60pct. Winds briefly settle down to
around 20kt lakewide Thu evening as high pres ridge quickly passes.
Winds then increase as the next clipper approaches. Enhanced by pres
falls passing eastward over and n of Lake Superior, s to sw winds
will ramp up to 35-40kt gales over much of Lake Superior, strongest
over the e half. The potential of winds to reach high end gales is
25-45pct over the e half of the lake. These winds will shift to the
nw Fri night. Aided by incoming pres rises and colder air, expect
gales of 35-40kt across central and eastern Lake Superior into Sat
morning. Very cold air pouring over the Upper Great Lakes afterwards
and lingering into next week will likely support winds of 25-30kt
across much of the lake.
The increasingly colder air arriving over weekend will support
periods where ice growth from freezing spray will become mdt to hvy
at times.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning until 10 PM EST /9 PM CST/ this evening for
LSZ162.
Gale Warning until 1 AM EST /midnight CST/ Thursday for
LSZ241>244-263-264.
Gale Watch from Friday morning through Saturday afternoon for
LSZ241>244-263-264.
Gale Watch from Friday morning through Saturday afternoon for
LSZ249>251-266-267.
Lake Michigan...
None.
&&
$$
SHORT TERM...BW
LONG TERM...Rolfson
AVIATION...07
MARINE...Rolfson