Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/13/20
AREA FORECAST DISCUSSION
National Weather Service Albany NY
948 PM EST Sat Dec 12 2020
.SYNOPSIS...
Seasonably mild and damp weather continues into Sunday as
a low pressure system tracks across the Great Lakes. An associated
cold front will cross the region on Sunday, ushering in a cool,
dry airmass. Chances for rain and snow return Monday. An even
greater chance for snow arrives on Wednesday with a possible
Nor`easter.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 948 PM EST...A low-level boundary remains draped across
south-central parts of the forecast area this evening. Abundant
low level moisture and light winds is allowing for widespread
low stratus clouds and some areas of dense fog, especially
across parts of the Catskills and mid Hudson Valley, where
visibility is under 1 mile in some locations. There may be some
improvement in visibility overnight, as low level winds start to
increase from the south as the boundary slowly drifts
northward, although pockets of low visibility is still likely to
occur within sheltered areas of the higher terrain.
In addition to the low clouds and fog, some showers are
expected, especially through about 1 AM. These showers have
already been impacting the Adirondacks, Mohawk Valley and Lake
George-Saratoga Region. Northern areas will have the best
chance at seeing some additional light rain overnight, but
showers can`t be ruled out anywhere. By the late night hours,
3km HRRR suggests the showers will mainly be north/east of the
region, as the low level boundary starts to shift northward. As
this occurs, temps will finally start to increase into the 40s
across the entire area, as our region starts to be located
within the storm`s warm sector, as the surface low pressure
area lifts across the eastern Great Lakes.
The region will then be fully entrenched in the warm sector on
Sunday before the cold front moves through in the mid to late
morning hours. Highs on Sunday are expected in the low 40s (up
north) to mid 50s (down south). Highs will be realized early up
north as the cold front moves through first with the potential
for some southern locations to warm into the mid 50s before the
front moves through. Temps then quickly drop behind the front as
cool, dry air is ushered in. Outside of cool and breezy
conditions, some peeks of sun may be possible across far
southern NY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
Southern stream energy, currently across the Rockies, will track
across the southern half of the CONUS through Sunday night
before lifting along the mid-Atlantic and New England coastlines
on Monday. Latest model guidance keeps the axis of heaviest
precip just off the coast, with low amounts clipping the
southern few zones of the forecast area. This would possibly
result in 1-2 inches of snow for the Berkshires, Litchfield
Hills and the high terrain of the eastern Catskills on Monday.
The rest of the area may see a few tenths up to an inch of snow
as temps in the valleys should warm into the mid 30s during the
day (with snow mixing with rain). A slight shift in the track
could change this scenario but it at least looks like a quick
moving wave so QPF should be limited to around a quarter of inch
or less.
That system exits Monday night as temps cool into the teens and
low 20s. Tuesday may be one of the only dry days in the
forecast, but it will be cold and breezy. Afternoon highs look
to be in the teens to low 30s, but most should see sunshine.
Normal high for Albany is 37 degrees.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Strong high pressure will be located over Quebec for Tuesday night
into Wednesday morning. With chilly temps in place aloft and a
light northerly flow, overnight lows will be very cold in the single
digits and teens, despite some increasing high clouds for the late
night hours.
On Wednesday morning, clouds will continue to increase, as a fast
moving upper level disturbance moves from the Tennessee Valley
towards the mid Atlantic States and surface low pressure rapidly
develops near the Carolina coast. While the day will start off dry,
some snow may start to spread into southern areas for late in the
day. There is good confidence that any p-type will be snow, plenty
of cold air will be in place at both the surface and aloft.
The low pressure will continue to deepen for Wednesday night into
Thursday morning as it lifts northeast off the eastern seaboard.
This storm system will have the capability to produce both moderate
to heavy snowfall amounts and high snowfall rates, although where
this occurs is still far from certain. There is still considerable
uncertainty regarding the exact track of this storm system, which
will determine how far north/west the steady snow will get. As of
right now, the operational guidance has tended to suggest that the
heaviest snowfall will be across eastern PA, northern NY, the NYC
area and into southern CT. This would give only a light snowfall (at
most) for the Capital Region on north/west. Still, many models
still suggest at least moderate snowfall is possible across the
Catskills, mid Hudson Valley and NW CT and there are several
ensemble members (both within the 12z GEFS/Euro Ensembles) that
suggests a more northern track is possible, with steadier/heavier
snowfall across the entire area, so the forecast is still far from
being locked in at this time.
The storm system will be departing on Thursday, with any lingering
precip ending across eastern zones by early afternoon. Behind the
storm system, cold and dry conditions look to be in place for the
remainder of the week and into the first part of next weekend.
Daytime temps will only be in the 20s, with single digits and teens
at night. With the possible snow cover on the ground, it will feel
quite wintry out. More snow showers are possible for the later
portion of next weekend.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Abundant low level moisture is allowing for lots of low stratus
clouds and fog this evening. Fog has been most widespread at
KPOU, where winds have been calm and dewpoints are highest.
IFR conditions for low clouds/fog seem likely at most sites over
the next few hours, but the potential for the low visibility will
start to decrease during the overnight (after midnight or so),
as southerly winds start to pick up. Still, flying conditions
will remain MVFR for the late night hours, as low clouds will be
difficult to remove until the morning hours. As surface winds
remain light, some LLWS is possible for KPSF/KPOU through about
06z, as 2 kft winds remain near 30-35 kts from the southwest.
There could be a few passing showers late this evening as well,
especially for KGFL.
Some improvement back to VFR conditions is expected on Sunday,
as winds switch to the west by the mid to late morning hours and
drier air starts to work into the region. Westerly winds may
increase to 10 to 15 kts by Sunday afternoon, with a few higher
gusts.
Outlook...
Sunday Night: No Operational Impact. NO SIG WX.
Monday: Low Operational Impact. Slight Chance of SHRA...SHSN.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: Moderate Operational Impact. Chance of SN.
Wednesday Night: Moderate Operational Impact. Chance of SN.
Thursday: Low Operational Impact. Chance of SN.
&&
.HYDROLOGY...
No widespread hydrological issues are expected through the
weekend into next week. Precipitation will be light this
weekend and mainly in the form of rain with chances for some
snow and rain showers Monday. Guidance continues to signal a
possible Nor`easter to impact the region during the middle of
next week. With the storm still several days away there is
uncertainty regarding track and QPF amounts. However, at this
time, snow would be expected.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...JLV
NEAR TERM...Frugis/JLV
SHORT TERM...JLV
LONG TERM...Frugis
AVIATION...Frugis
HYDROLOGY...IAA/JLV
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
500 PM CST Sat Dec 12 2020
...Aviation Update...
.DISCUSSION...(This evening through Saturday)
Issued at 255 PM CST Sat Dec 12 2020
Surface high pressure was building south onto the plains today,
reinforcing the cooler airmass in place across our region. Between
the cloud cover, cooler air and snow on the ground, temperatures
have struggled to climb today and average in the mid 20s to low
30s this aftn.
Tonight another storm system currently over the Rockies will emerge
onto the southern plains, tracking into the TX Panhandle on Sunday.
The brunt of the snowfall with this system will remain well to our
south and west across western/southwest KS, however some of the high
resolution models clip our far southwest KS counties with a little
snowfall or flurries...but with little if any accumulation. Although
we`ll be on the northern edge of the precip, have added the
potential for some snow/flurries for locations south of a
Phillipsburg to Osborne, KS line. Also tonight have maintained the
potential for patchy fog development give recent moisture/light
winds although models are hit and miss on potential development
with the NAM/HRRR the most aggressive with the lowest visibilities
across south central Nebraska, mainly west of Highway 281.
Sunday will see decreasing cloud cover and increasing insolation
will aid in warming temperatures in the 30s...with readings
holding several degrees cooler over snowpack...then an upper
disturbance crossing the northern plains will send some cooler air
south across our region heading into Sunday night. On Monday, dry
weather is expected with another day in the 30s, with increasing
south/southeast winds ahead of a storm system deepening over the
Rockies.
As the western system edges onto the plains late Monday,
isentropic lift (290K surface) increases across western and
central Neb/KS, with snow chances increasing as early as Monday
evening, but with better chances for snow arriving Monday night
thru Tuesday in increasing dynamics/forcing as the upper trough
crosses the central and southern plains. Models have had varying
solutions with this system and resultant snow potential for our
area as the main upper low tracks well to our south across
Oklahoma. The latest operational NAM suggests the main snow band
will remain to our west (and then south), whereas the GFS/ECMWF
are in decent agreement with snow developing across
western/central Neb and Kansas. Did not deviate from the ensemble
blend which is supported by the ECMWF/GFS with the potential for
an accumulating snow event Monday night and Tuesday...with
forecast snow amounts in the 1-3" range for locations west of
Highway 281...and these amounts will be refined as details become
more clear.
The weather dries out for the remainder of the extended period
and temperatures will gradually moderate through the end of the
week. If model timing holds, a cold frontal passage Friday night
associated with a quick moving system may cool temps back
slightly for Saturday.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 454 PM CST Sat Dec 12 2020
Low end MVFR ceilings currently continue across the area. Expect
that these ceilings will slowly drop back to IFR this evening and
tonight, but how low they go is a little bit uncertain. Some
guidance shows that we could even stay MVFR all night.
In addition, HRRR and RAP shows some patchy fog developing over
portions of the area tonight as winds go light and variable. Exact
location is also uncertain, but it appears that KEAR has a better
chance for fog than at KGRI.
Skies should clear out fairly quickly Sunday morning, likely
returning to VFR between 12-15Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Fay
AVIATION...Mangels
Area Forecast Discussion
National Weather Service Wichita KS
912 PM CST Sat Dec 12 2020
...Winter Mesoscale Update...
.MESOSCALE DISCUSSION...
Issued at 909 PM CST Sat Dec 12 2020
Recent RAP analyses depict a noticeable increase in large scale
forcing for ascent is ongoing from the Four Corners Region into
southwest Kansas. This is likely occurring due to 1) the
approaching left exit region of a 120kt jet, 2) increasing mid-
level WAA, and 3) increasing mid-level frontogenesis. Regional
radar supports the recent RAP analyses, showing a consolidating,
and expanding, area of snow from the Colorado Front Range east
into southwest Kansas. Beneath this band, recent SFC obs have
dropped as low as a mile in light snow.
The area of increasing mid-level frontogenesis along the Colorado
Front Range is likely the beginning stages of what will become the
focus for some of the strongest forcing as the upper low ejects out
of the Southwest US. Recent 18z/21z/00z model guidance differs some
on where the strongest lift will be focused, but the consensus still
puts the greatest lift and highest snowfall rates along and south of
the KS/OK border. Of note, the 00z NAM coming in has trended a bit
further south with the heaviest QPF/snowfall (it was one of the
models that has been further north in recent runs). The RAP,
meanwhile, continues to keep the HWY 54/400 corridor in play for
accumulating snow. Based on recent model, satellite, radar, and SFC
obs trends, the forecast appears to be in pretty good shape.
However, as the band of snow pivots E/SE across the region, it looks
like it may clip parts of southeast Kansas with a bit more snow than
originally forecast. Some model guidance has actually trended up in
this area as the upper low passes by to the south with some enhanced
lift. Given these trends, I will expand the Winter Weather Advisory
east to include our entire southern row of counties. Otherwise,
snowfall amounts look good. I just nudged values up a tad across
Harper County where the best chance of 1"/hr rates is. That area
will need to be closely monitored for a possible upgrade to a Winter
Storm Warning.
Martin
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 214 PM CST Sat Dec 12 2020
Current satellite water vapor imagery shows healthy upper level PV
wave diving southeast across Nevada. This system will continue to
race southeast tonight and eject into the Texas panhandle region by
daybreak tomorrow. Deep isentropic ascent will cause snow to develop
across western Kansas this evening and spread eastward towards south
central KS, mainly between midnight-3AM. Strong isentropic lift
combined with negative EPV with-in dendritic snow growth layer aloft
will yield high 1"/hr snowfall rates at times. The greatest impacts
to road conditions from these high snowfall rates is expected to
occur between 3AM-9AM, and affect locations mainly along and south
of a Langdon to Wichita, to Sedan line. Therefore we expanded the
winter weather advisory to include a few more counties. Total snow
amounts will range from 1 to 4 inches in the advisory area, with a
few locations possibly surpassing 4 inches near the Kansas/Oklahoma
border area. The system is fleet-footed so the period of isentropic
lift/snow will be short lived and quickly taper off from west to
east tomorrow morning over south central Kansas, and southeast
Kansas by early afternoon.
Quiet weather is expected for Sunday night through Monday night
before next weather system approaches the area on Tuesday. Model
trends continue to deepen/strengthen and shift the position
southward with this next weather system for Tuesday. Lift/mid-level
instability appears less favorable compared to late tonight-Sunday
morning`s event, however this event could be a little more prolonged
which still supports decent chances for accumulating snowfall to
occur across Kansas.
.LONG TERM...(Wednesday through Saturday)
Issued at 214 PM CST Sat Dec 12 2020
Wednesday will see cold below normal temperatures in the wake of
Tuesday`s weather system. Otherwise a gradual warming trend with dry
weather will then commence through the end of next week as warmer
air spreads over the central plains. The extent of warming will be
predicated on which locations witness snowfall from Sunday and
Tuesday weather systems, as the new snowpack would hinder daytime
temperature recovery efforts.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 559 PM CST Sat Dec 12 2020
* Snow to impact southern Kansas tonight/Sunday
* LIFR conditions possible late tonight into Sunday (southern KS)
A dynamic storm system over the Four Corners Region will move across
the Southern Plains late tonight/Sunday. On the north side of this
system, a band of snow will develop across Colorado/New Mexico, and
translate east across KS/OK. This will lead to widespread reductions
to VIS across southern KS, including the potential of LIFR
conditions at times. The best chance of LIFR conditions will be
between 09z-15z Sunday. Snowfall rates may reach 1"/hr during
that time as well. There remains some uncertainty regarding how
far north the band of snow will reach. With this TAF issuance, I
removed the SN mention from KRSL/KSLN, but we`ll be watching this
closely. Snow will taper off from west to east by Sunday
afternoon. Where snow occurs, accumulations are likely on roads
and runways, with 1-3" possible as far north as KICT/KHUT (higher
amounts closer to the OK border). Low clouds may begin to move
out as early as Sunday afternoon across north-central Kansas, but
I slowed the departure by a few hours.
EXTENDED OUTLOOK: Another round of low clouds and accumulating snow
is possible on Tuesday across parts, if not all, of the area.
Martin
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 28 36 20 35 / 80 100 0 0
Hutchinson 26 39 20 39 / 70 80 0 0
Newton 28 39 21 40 / 50 70 0 0
ElDorado 29 38 21 38 / 60 80 0 0
Winfield-KWLD 31 34 19 34 / 80 100 0 0
Russell 21 41 17 39 / 20 10 0 0
Great Bend 23 40 17 39 / 70 40 0 0
Salina 25 42 20 42 / 10 10 0 0
McPherson 26 40 19 40 / 30 30 0 0
Coffeyville 32 35 21 37 / 60 100 0 0
Chanute 31 38 22 41 / 40 80 0 0
Iola 30 39 21 42 / 30 60 0 0
Parsons-KPPF 31 37 22 39 / 50 90 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 3 AM to 3 PM CST Sunday for KSZ082-
083-091>093-098.
&&
$$
MESOSCALE...RM
SHORT TERM...CDJ
LONG TERM...CDJ
AVIATION...RM
Area Forecast Discussion
National Weather Service Lincoln IL
631 PM CST Sat Dec 12 2020
.SYNOPSIS...
Issued at 252 PM CST Sat Dec 12 2020
Expect cloudy skies rest of today and tonight along with some
occasional flurries or drizzle well into this evening. clouds will
be slow to clear on Sunday but expect overall dry conditions with
highs in the upper 40s to lower 40s. The first half of the
upcoming week will see highs only in the lower to mid 30s.
&&
.UPDATE...
Issued at 631 PM CST Sat Dec 12 2020
Latest surface analysis shows low pressure over southeastern
Ontario with a cold front extending southward into the
Appalachians. A trailing trough axis is noted across central
Illinois from near Danville to Taylorville. Low clouds and
drizzle/sprinkles persist across much of the area: however, the
precip is beginning to transition to flurries west of the I-55
corridor as evidenced by recent obs and surface reports. The light
precip is being aided by a short-wave trough traversing the
region. As this feature tracks into the Great Lakes and the
surface trough sags south of the I-70 corridor, the very light
precip will taper off and come to an end by midnight. Made some
adjustments to the forecast to highlight the chance for flurries
as far east as a Paris to Shelbyville line before the precip ends.
Further east/south, only sprinkles or drizzle will be observed.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 252 PM CST Sat Dec 12 2020
Water vapor imagery reveals upper low centered over Michigan and
lifting northeast while surface obs show a weak frontal trough
stretching southwest across central Illinois near the I-57
corridor this afternoon. Radar shows weak returns near and behind
this boundary and combination of continuing low level moisture and
cyclonic flow will support the possibility of drizzle or a few
flurries well into the evening, especially as a shortwave trough
currently over SW/Central MO lifts across the area. Behind this
wave, ridging will build in aloft and expect dry weather to
prevail through the remainder of tonight and tomorrow. Skies are
unlikely to clear tonight but low level anticyclonic flow
overspreads central Illinois Sunday which may help lead to a few
peeks of sunshine during the day. Expect quiet weather most of the
day with highs in the upper 30s NW to lower 40s SE. Low pressure
will move across the Tennessee Valley Sunday evening and overnight
and the northern edge of the precip shield may extend into
portions of SE IL south of the I-70 corridor.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 252 PM CST Sat Dec 12 2020
High pressure will build south from the Canadian Rockies across
the central Great Plains late this weekend this slowly spread
east across the Midwest and Great Lakes Monday and Tuesday. This
will provide temperatures slightly below the seasonal norms to
start the upcoming week, but otherwise quiet weather is expected
under the influence of the ridge.
Meanwhile, a strong shortwave will dig across the Intermountain
West and into the southern Great Plains early next week, then
lift across the mid Mississippi Valley Tuesday night into
Wednesday. At this time, models are in reasonable agreement with
timing and track of this system, which could bring some light snow
accumulations to portions of east central and southeast Illinois
Tuesday night.
High pressure will build back across the region midweek with a
return to dry conditions and near to slightly below normal
temperatures. South winds developing behind the ridge axis late
in the week will result in a gradual warming trend to end the
week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 555 PM CST Sat Dec 12 2020
Low MVFR/IFR ceilings persist across central Illinois late this
afternoon. Upstream obs show cloud bases gradually rising near the
Mississippi River, with a pocket of mostly clear skies noted
across central/western Iowa. Based on satellite loops and HRRR
forecast, it appears this clear or partially clear area will push
into KPIA by around 06z and perhaps to KBMI by around 09z. Further
south, MVFR ceilings will persist at the I-72 terminals through
the entire night. NAM forecast soundings suggest the low clouds
will scatter by mid to later Sunday morning: however, they will be
replaced by a mid-level cloud deck at around 12,000 feet. Winds
will initially be W/NW at around 10kt this evening, then will back
to W/SW and decrease by Sunday afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SYNOPSIS...Deubelbeiss
SHORT TERM...Deubelbeiss
LONG TERM...Deubelbeiss
AVIATION...Barnes
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
845 PM CST Sat Dec 12 2020
.UPDATE...
845 PM CST
The main update to the forecast this evening was to drop the lake
shore flood warning for Lake IL and northern Cook. Winds have
turned offshore here, and while lake levels and waves remain
elevated the threat of significant lake shore flooding has
diminished. Conditions will also improve in this area overnight
as the higher waves shift offshore. We did not make any changes to
the lake shore flood advisory farther south, though it is
possible that this could be ended prior to 6am for central Cook.
In addition to dropping the lake shore flood warning, we also
added a period of light snow and flurries into the forecast for
the rest of this evening. Radar imagery and surface observations
continue to show an area of light snow and flurries moving
eastward across northern IL in association with a weak mid-level
impulse. Expect this area of light snow and flurries to continue
for a couple hours this evening before ending overnight. No real
accumulation is expected, so impacts should be minimal.
KJB
&&
.SHORT TERM...
245 PM CST
Through Sunday night...
The surface low responsible for the active weather the past couple
days is quickly lifting off to the northeast this afternoon along
with the heavy rain. Most areas picked up 1 to 2 inches of rain
the past 24-30 hours. There remains a weakening deformation band
over the Chicago metro of predominately rain, mixing with snow at
times. Elsewhere, drizzle has been the predominant precipitation
type the past few hours with the loss of cloud ice aloft. Could
see some freezing drizzle try to sneak in this afternoon northwest
of the Chicago metro, but surface temperatures look to remain
marginal enough to limit any impactful accumulations if it were
to briefly develop. A ragged N-S oriented lake effect band has
also set up along the WI/IL lakeshore. This feature will continue
to drift south along the IL shore into NW Indiana through the
evening hours likely falling mostly as drizzle/flurries.
There is some noted clearing over the MN/IA/WI border region that
could try to drop into the area tonight, as depicted by the
ECMWF. This would support a decent temperature drop overnight,
especially across our northwestern zones, where low 20s are
possible. Low 30s are expected where low clouds will linger near
and south of the lake.
Sunday looks to remain precip free for most areas, perhaps with
some lingering light lake effect precipitation in the AM across
northwest IN. The Southern Plains low expected to develop looks
to remain well to our south. Low clouds will keep things cool
tomorrow with highs in the mid to upper 30s. Will note that the
15Z RAP shows there may be some drizzle/freezing drizzle issues to
our east into northeast IN, western MI as a progressive shortwave
swoops across the Upper Great Lakes Sunday night. Will keep an
eye on whether this tries to sneak into our area Sunday night
as temperatures will likely drop into the 20s.
Petr
&&
.LONG TERM...
1256 PM CST
Monday through Saturday...
We`ll start the workweek on a cool note as a reinforcing shot of
cP air oozes into the region in the wake of a (dry) shortwave
which will translate through during the morning hours. This
feature will kick up some slight northwesterly breezes which, when
combined with daytime temperatures in the upper 20s and lower 30s
will result in wind chills probably hanging out in the teens and
lower 20s through the day.
Upper-level moisture will begin to increase later on Monday
evening and into Tuesday as the next disturbance drops through the
Great Basin and begins to encourage a southerly low-level mass
response out across the Central Plains. The expected thickening
cirrus shield should help keep the bottom from really falling out
in the overnight low department into Tuesday morning, with the
floor on temperatures into the single digits. The offered
blended guidance temperatures in the teens and 20s looks
reasonable, although if cloud cover does indeed invade as quickly
as some of the guidance suggests, we may be several degrees warmer
than this.
The aforementioned disturbance is forecast--with a reasonable
amount of model agreement for the time range--to translate east
across the Mississippi River valley as a neutral to slightly
positively-tilted wave Tuesday night and Wednesday. The core of
the parent upper vort lobe may get close enough to our area to
squeeze out a brief period of snow late Tuesday night and
Wednesday morning well south of I-80, but a notable dry air in
the 4-10 kft level with northward extent, combined with sufficient
uncertainty regarding the exact evolution of the salient upper
level features precludes the addition of any low PoPs at this
time.
The energetic upper pattern continues through the rest of the week
and into the upcoming weekend, with several embedded disturbances
within the wave train slated to drift overhead during this portion
of the forecast. However, any deeper saturation is ephemeral in
extended progs, and the periods of more appreciable forcing for
ascent don`t really seem to coincide with what meager moisture is
floating around in the mid-levels. As a result, we`ll continue to
feature a precipitation-free forecast through Saturday with
gradually moderating temperatures into the towards near or
slightly-above normal values.
Carlaw
&&
.AVIATION...
For the 00Z TAFs...
550 PM CST
The concerns include:
* Lake effect -RA/SN this evening
* MVFR and patchy IFR CIGs this evening likely scattering between
04-06z at IL sites, Sunday AM for GYY
* Patchy MVFR CIGs possible at times Sunday and Sunday evening
Overall mostly quieter conditions are in store. The main item of
note this evening is ongoing lake effect/enhanced precip into MDW
and GYY, likely to stay east of ORD and then shift east of all
sites later this evening. MDW has been reporting -RASN, while GYY
is -RA, but could see some snow mix there in over next few hours.
After temporary IFR CIGs at MDW end this evening, otherwise prevailing
low-mid MVFR CIGs should scatter over Illinois tonight, but probably
hold on until mid morning or so for GYY. With pockets of MVFR CIGs
upstream and lingering moisture in that 1000-2000 ft layer, can`t
rule out some periods of BKN CIGs during the day Sunday and again
later Sunday evening with a weak disturbance approaching. Northwest
winds, with gusts in 15-20 kt range near the lake, will ease tonight,
and then become more westerly on Sunday.
Castro
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Lakeshore Flood Advisory...ILZ104 until 6 AM Sunday.
IN...Lakeshore Flood Advisory...INZ001-INZ002 until 9 AM Sunday.
LM...Small Craft Advisory...IL nearshore waters until 9 AM Sunday.
Small Craft Advisory...IN nearshore waters until noon Sunday.
&&
$$
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