Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/11/24
Area Forecast Discussion
National Weather Service Buffalo NY
946 PM EST Tue Dec 10 2024
.SYNOPSIS...
Rain this evening will taper off to drizzle, with some fog
developing tonight. Another round of rain arrives Wednesday
which will change over to wet snow from west to east with some
minor accumulations across the higher terrain possible by
Wednesday evening. Locally heavy lake effect snow will then
develop east of Lake Erie and Lake Ontario Wednesday night and
continues through early Friday, before another warming trend
arrives over the weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
A weak impulse tracking northeast towards the Lower Lakes is
bringing a period of light rain to the region this evening. Once
this impulse passes through the area we will see a brief break
in the steadier precipitation. However...with plentiful low-
level moisture in the boundary layer, there is the potential we
could see a period of drizzle and fog tonight before more
precipitation moves into the region by early Wednesday morning.
A mid level trough will quickly dig and sharpen over the Mississippi
Valley and then become negatively tilted as it swings into the mid-
Atlantic region tonight. In the process...a tightening of a
baroclinic zone on the eastern flank of the trough will set up from
NY/PA to MD/VA. An elongated frontal wave is then advertised to move
north along this boundary on Wednesday, with widespread `rain`
spreading back across the area early Wednesday morning and
continuing throughout the day. Strengthening CAA on the western
flank of this front will begin the process of changing rain over to
wet snow, first across the higher terrain east of Lake Ontario and
then everywhere before lake effect snows fire up east of both lakes.
Where precipitation changes over to snow first (higher terrain),
some accumulations (1-3 inches) will be possible. Winds will also
pick up by late Wednesday afternoon/evening, with gusts up to 30
mph. It will also turn much colder with temperatures falling over
the course of the day. Expect mercury readings to fall into the 30s
to upper 20s in spots by sunset.
Overall...rainfall amount will be on the order of 0.33 to 0.50
inches from the Genesee Valley west across the Niagara Frontier and
the Southern Tier. East of the Genesee Valley, amounts will range
from 0.50 to 1.00 inch, with slight higher amounts in spots. Taking
a look at Hydro guidance (GEFS/NAEFS/HEFS), creeks and rivers will
`likely` see some measure of rises given what still remains in the
snowpack. More on this in the hydro section.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
...HEAVY LAKE EFFECT SNOW WEDNESDAY NIGHT THROUGH FRIDAY...
The pattern will briefly amplify across North America, with a strong
ridge building over the Rockies and a strong, deep trough digging
into the east. This trough will deliver a very cold airmass to the
region, supporting strong instability over the lakes and another
heavy lake effect snow event. Lake induced equilibrium levels will
peak at around 15K feet Wednesday night and early Thursday as the
coldest mid level air crosses the region, then steadily lower later
Thursday through Friday as the cold airmass becomes more shallow
with time.
Prior to the start of lake effect snow, rain will still be in the
process of changing to wet snow from west to east across the area
Wednesday evening. Expect some minor, slushy non-lake effect
accumulations across the higher terrain with this, and perhaps a
slushy coating for lower elevations.
Off Lake Erie...
A band of lake effect snow will quickly develop late Wednesday
afternoon or evening on the heels of the departing synoptic
precipitation. Expect initial band development well south of Buffalo
across the western Southern Tier and southern Erie County. The band
will begin to strengthen in this area, then start to move northward
through Erie County overnight. Both the GEM and HRRR suggest backing
low level flow ahead of a shortwave moving through the base of the
mid level trough will carry the band all the way north to near or
over Buffalo and Batavia briefly late Wednesday night and early
Thursday morning before settling back south a little towards central
Erie County and the Wyoming/Genesee County border by mid morning
Thursday.
Latest guidance suggests the band may creep back north towards the
immediate Buffalo Southtowns and possibly South Buffalo and some of
the eastern suburbs for a time later Thursday through Thursday
evening, before moving back south again Thursday night. The band
will generally remain across Southern Erie County and the western
Southern Tier from later Thursday night through Friday, where it
will steadily weaken as inversion heights lower.
The Lake Erie band should reach peak intensity later Wednesday night
through Thursday, when snowfall rates may reach 2-3" per hour.
Expect a weakening trend Thursday night and especially Friday.
As far as storm totals go, expect 2-3 feet in the most persistent
bands. The bullseye is most likely to be in southern Erie County,
with 1-2 feet over western Chautauqua, far northwest Cattaraugus,
and western Wyoming counties. The more immediate Buffalo Southtowns
(that are located in the northern Erie zone) and southern Genesee
County may see 10-20 inches if the band persists long enough that far
north. This is another extremely close call for the City of Buffalo,
with South Buffalo possibly accumulating 1 foot or more while North
Buffalo has very little.
Conditions seem supportive of strong inland penetration with this
band, with moderate accumulations possibly extending into the
western Finger Lakes. Also included an Advisory for Livingston
County, with 4-7" possible in a narrow band across central or
northern Livingston County. This could potentially extend into
portions of Ontario County as well, but confidence is lower that far
from the lake. Snow showers will occasionally peel off the eastern
end of the band and make it all the way into Oswego County and the
southern Tug Hill.
Off Lake Ontario...
Expect lake effect snow to develop later Wednesday evening as the
synoptic precipitation is exiting. Initial lake enhanced upslope
regime across the Tug Hill Plateau will evolve into a more pure lake
effect band later Wednesday night, with the band of snow moving
north towards Watertown and Fort Drum by Thursday morning. The band
may not be particularly strong at first, with some shear still
located in the boundary layer. The band should strengthen Thursday
as boundary layer flow becomes better aligned. The band should spend
most of Thursday over or near Watertown and central Jefferson
County.
Boundary layer flow will then veer more westerly Thursday evening,
carrying the band a little south to center more on the northern and
central Tug Hill region. The highest snowfall rates are likely to
occur Thursday night, when the most favorable convergence is
forecast over the lake, and when lake effect snow will begin to
intersect terrain. Friday, lake effect snow should remain near the
Oswego/Jefferson County border and extending inland across the Tug
Hill Plateau. Inversion heights will steadily lower and the airmass
will dry out, resulting in a weakening of the band later in the day,
and will also force it to shrink back towards the lakeshore.
The Lake Ontario band will likely reach peak intensity later
Thursday through Thursday night or early Friday, when snowfall rates
may reach 2-3" per hour. Expect a weakening trend later Friday as
inversion heights lower.
As far a storm totals go, expect 2-3 feet in the most persistent
bands. The bullseye will most likely be found across the northern
Tug Hill to just south and east of Watertown. This will be
surrounded by a larger footprint of 1-2 feet of snow including
Watertown and central Jefferson County, central and northern Lewis
County, and far northern Oswego County.
Finally, it will turn very windy later Wednesday night through
Thursday evening. Winds may gust up to 40 mph at times, resulting in
considerable blowing and drifting snow where lake effect snow
occurs.
Outside of lake effect areas, expect mainly dry weather and even
some sunshine Thursday through Friday. It will be quite cold, with
highs in the mid 20s for lower elevations and around 20 for higher
terrain Thursday and Friday. Lows Thursday night will be in the
teens, with wind chills in the single digits.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Surface high pressure over NY/PA and New England Saturday morning
will move east and off the New England coast later in the day. This
will provide mainly dry weather, and after a chilly start, a notable
warming trend will develop. Highs will reach the upper 30s to near
40 in Western NY, and upper 20s to lower 30s for the North Country.
The warming trend will continue into Sunday, with highs well into
the 40s for most lower elevation areas. A weakening mid level
shortwave will cross the eastern Great Lakes later Saturday night
through Sunday night. This system will produce some light rain
across the region, which may mix with wet snow at the start and
across higher terrain.
Another trough and surface cold front will approach Tuesday, with
increasing chances of showers. Temperatures will continue to run
above average early next week, with much of the precipitation
falling as just rain.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A weak wave moving through northeast towards the Lower Lakes
with rain overspending the area. This will bring lowering cigs
and vsbys from southwest to northeast across area TAF sites. The
steady light rain will then taper off to drizzle late this
evening, some fog will also be found across area terminals
overnight. This will produce a mix of MVFR to IFR conditions
areawide.
Outlook...
Wednesday...MVFR/IFR with rain changing to wet snow from
west to east.
Wednesday night...MVFR/IFR with wet snow tapering off, then
heavier lake effect snow east of the lakes with local LIFR.
Thursday through Friday...Local lake effect snow with LIFR east
of Lake Erie and Lake Ontario. Close call for KBUF, heavier
snow may remain just south of the airfield. VFR/MVFR elsewhere.
Saturday...Mainly VFR with a chance of rain or snow showers.
Sunday...MVFR to IFR with rain showers.
&&
.MARINE...
Quiet marine conditions expected through most of Wednesday as a weak
pressure gradient across the lower Great lakes maintains relatively
light winds.
A strong cold front will sweep across the eastern Great Lakes late
Wednesday and Wednesday night leading to increased westerly winds.
Sustained speeds of 30 knots are likely from Wednesday night through
Thursday afternoon with the potential for gale force winds,
especially behind the cold front Wednesday night into Thursday over
the eastern basin of Lake Erie and all of Lake Ontario. Gale Watches
have been issued on both lakes during this time frame.
Conditions will improve on Lake Erie and Lake Ontario Friday as
high pressure nears the region and winds lighten considerably
and turn more southerly.
&&
.HYDROLOGY...
Another round of rainfall with 0.25"-0.50" expected through
Wednesday from the Genesee Valley west. Higher amounts will be
found east of the Genesee Valley ranging from 0.50" to 1.0",
slightly higher amounts will be found east of Lake Ontario (Tug
Hill region).
These rainfall amounts, combined with ongoing snowmelt, will
bring within-bank rises on area rivers and creeks through
midweek. Official forecasts from the RFC along with ensemble
forecasts continue to suggest a low chance of flooding. The
Black River basin, with more snow to melt and higher rainfall
amounts, will see the most significant rises later this week,
and a low chance of reaching minor flood stage.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Lake Effect Snow Warning from 7 PM Wednesday to 7 PM EST
Friday for NYZ006>008.
Lake Effect Snow Warning from 10 PM Wednesday to 1 PM EST
Friday for NYZ010-011.
Lake Effect Snow Warning from 4 PM Wednesday to 1 PM EST
Friday for NYZ012-019-020-085.
Winter Weather Advisory from 7 PM Wednesday to 4 AM EST Friday
for NYZ013.
MARINE...Gale Watch from Wednesday evening through Thursday afternoon
for LEZ040-041.
Gale Watch from Wednesday evening through Thursday
afternoon for LOZ042>045-062>065.
&&
$$
SYNOPSIS...AR
NEAR TERM...AR
SHORT TERM...Hitchcock
LONG TERM...Hitchcock
AVIATION...AR
MARINE...AR/TMA
HYDROLOGY...Hitchcock/TMA
Area Forecast Discussion
National Weather Service Cheyenne WY
231 PM MST Tue Dec 10 2024
.KEY MESSAGES...
- High Wind Warnings issued for the southeast Wyoming wind prone
locations Tuesday afternoon until Wednesday evening. Wind
gusts up to 65 MPH possible.
- Isolated snow showers in the NE panhandle and east-central
Wyoming may result in a coating to an inch of snow on Tuesday
afternoon and evening.
- Seasonably cool temperatures are expected to persist through
the remainder of the week into the weekend.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 219 PM MST Tue Dec 10 2024
Yet another surface cold front is progged to push through the CWA
later this afternoon and through the evening hours. Unlike Monday`s
front, this front will likely have a little less precipitation
associated with it. Hi-Res guidance like the HRRR shows sparse
coverage of snow showers this afternoon ahead of the front. Behind
the front, some light stratiform precipitation will be possible,
mainly for the northern zones and into the Nebraska panhandle.
Current visible satellite imagery shows a large swath of stratus
clouds to the north, moving into Converse and Niobrara
Counties. Ground observations from northeast Wyoming show light
snow falling across these areas as well. Stratiform
precipitation will likely make its way into the northern zones
late this afternoon and continue through the evening hours.
Snow accumulations will be minimal, anywhere from a dusting to
an inch in these areas.
High Wind Warnings still look on track for the southeast Wyoming
wind prones. This gradient driven wind event is the result of the
incoming cold front which will produce a surface trough east of the
Laramie Range, and a strong surface high over the Colorado Rockies.
This scenario will set the stage for a strong MSLP gradient over the
CWA, leading to high winds. Winds aloft will max out around 55 kts
with strong subsidence, so these winds will likely make it down to
the surface. High winds will continue through the day Wednesday, but
gradually weaken through the afternoon as a weak upper-level
ridge over the Great Basin shifts further east. This will cause
MSLP gradients over the CWA to relax a bit, but remain elevated
enough to still cause blustery conditions over the wind prones
Wednesday night. Aside from winds, expect warmer conditions on
Wednesday as the exiting upper-level trough ushers in warmer 700
mb temperatures.
Uneventful weather is expected for the day Thursday. Winds by
Thursday will ease, but clouds will increase throughout the day
ahead of an incoming shortwave. Precipitation is not expected,
however some snow showers may begin to move into the mountains
overnight. Despite the cloud cover, most locations can expect to see
slightly above average high temperatures in the 40s.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 219 PM MST Tue Dec 10 2024
A more active synoptic weather pattern will take over late this week
into early next week, but it remains unclear whether this will
translate to any snowfall for our area.
Model guidance is in fairly good agreement showing the next
shortwave trough passing through the area from west to east around
Friday. While the upper level presentation of this system looks
decent, and with a favorable track for precipitation, a secondary
upper level low positioned just to the north of the main along with
very limited column moisture will prevent widespread snowfall.
Westerly flow will still produce some snow showers in the mountains
Friday, but probabilities of Advisory criteria (6+") are less than
50% at this time. Elsewhere, expect something similar to the last
few events with a few light snow showers or flurries scattered about
but minimal impacts. This system will knock down temperatures a
touch, with near average high temperatures expected on Friday and
breezy to windy conditions returning to the wind prone areas. This
could be a marginal high wind event for the I-80 wind prone areas,
but probabilities of criteria gusts is about 40% or less at this
time.
Temperatures will warm up again for Saturday to perhaps 5-10F above
average. This ridge aloft looks fairly transient, with another
stronger upper level trough on its tail for the Sunday/Monday time
period. Sunday`s high temperatures have considerable uncertainty
depending on the timing of the frontal passage. Ensembles are split
into two camps, with the GEFS and ECMWF ensemble systems showing
distinct separation. The GEFS mean shows a faster, weaker trough
that passes through Sunday, leading to much colder highs on Sunday,
light mountain snow, and widespread strong winds. This scenario
would also warm up faster on the tail end, with moderating
temperatures by Monday. A majority of ECMWF ensemble members fall
into a slower, stronger cluster that would deliver another mild day
for Sunday, followed by much colder conditions on Monday and a
better chance for widespread light to moderate snowfall. Even though
the high end precipitation amounts are not too impressive (ensemble
90th percentile is in the 0.1" to 0.25" QPF range for the plains),
strong winds on the backside of a departing cyclone could increase
the relative impact in this scenario. With little insight into which
scenario will be favored, opted to make minimal changes from the NBM
consensus.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1036 AM MST Tue Dec 10 2024
Another round of light snow developing this afternoon and
evening may bring periods of MVFR to IFR conditions to the NE
panhandle terminals, but confidence is fairly low. Otherwise,
expect gusty northwest winds across the board today, with gusts
lingering into the overnight in Wyoming. LLWS may develop
tonight at KCYS and KLAR.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 5 PM MST Wednesday for WYZ106.
High Wind Warning until 5 PM MST Wednesday for WYZ110-116-117.
NE...None.
&&
$$
SHORT TERM...SF
LONG TERM...MN
AVIATION...MN
Area Forecast Discussion
National Weather Service Goodland KS
416 PM MST Tue Dec 10 2024
.KEY MESSAGES...
- Flurries/sprinkles remains possible through tonight, generally
favoring NW Kansas and SW Nebraska. There is a 10% chance for
a stronger shower to produce a dusting of snow.
- Mild Wednesday and then a more progressive pattern with
periods of above normal and below normal temperatures.
Forecast remains dry for now.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 1206 PM MST Tue Dec 10 2024
The main focus for this period will be on the potential for brief
but intense snow showers favoring eastern portions of the area this
afternoon. After the downtrend of guidance with the environment not
looking as supportive as typically is the case in conditional events
guidance has begun trending back to a more supportive
environment for these snow showers. RAP has been consistently
showing this morning strong lift in the form of omega in the
dendritic growth zone along with a fairly pronounced 850mb
frontogenesis band quickly moving through the area this
morning. As what was seen yesterday negative values of EPV*
that shows convective potential continues to be seen along with
some favorable values seen in the bottom layer of the dendritic
growth zone. RAP isentropic lift has also returned as well in
both the 285K and 290K levels which would further support lift.
With all of this combined the scene appears to be set for a
period of heavy snowfall with the potential for snow rates up to
1 inch per hour. The caveat to everything is will the low
levels be to dry to maximize this potential at the surface and
will snow even make it to the surface? Continued dry air
advection throughout the day is forecast to keep dew points in
the upper teens to low 20s along with temperatures rising into
the upper 30s to low 40s which would yield dew point depressions
of nearly 20 degrees which is where my concern lies. With this
in mind I capped the chances for precipitation at 24 percent
keeping the slight chance wording as this is appearing to be a
low confidence high impact event this afternoon.
Should the snow potential come to fruition what would the impacts
be? As mentioned above there is the potential for 1" per hour
snowfall rates which would lead to a quick accumulation but with how
quickly this area of snow is forecast to be moving overall snowfall
amounts would likely be fairly minimal in general but would come
down hard enough to quickly cover roads. Within the snow shower, a
drastic reduction of visibility may occur due to the snow rates and
the fact that winds will already be gusting 30-35 mph leading to
some concerns regarding blowing snow as the snow is falling and
perhaps some brief whiteout conditions. Slick spots on roadways as
well will also be a concern as road temperatures according to the
Nebraska Department of Roads is currently in the mid 30s across
Hitchcock county which will lead to the assumption that other roads
will be fairly similar.
As for timing, fairly decent agreement on the potential entering
northern portions of Hitchcock and Red Willow counties around
21Z(3pm CT) and moving fairly quickly to the southeast reaching
portions of Sheridan and Graham counties around 23Z (5pm CT).
The concern with this is that this will be around the time that
schools release which would further lead to impacts should this
materialize. As for coverage however, its not appearing that
this will be a large area of snow as it may only be a single
cell or two so the coverage in impacts would be fairly limited.
All in all my confidence in this occurring is around 15-20%
which is similar to yesterday but would be higher if it wasn`t
for the dry air at the surface which may lead to this event not
occurring. As mentioned above this event is a conditional low
confidence high impact.
Through this evening across the remainder of the night additional
mid level moisture moves into the area from the north which may lead
to the development of additional snow showers or flurries. I wound
up adding in a corridor of around 25% chance of snow showers again
roughly along and north of line from Benkelman to Hill City. The
same parameters are in place this evening and overnight for intense
snow showers but this time the low levels are more saturated which
has increases my confidence that this round should reach the
surface; this could also a case of the first round this
afternoon doesn`t reach the surface but it helps saturates the
low levels for this evening? Timing for the evening round
currently is around 8pm CT entering Dundy county and is forecast
to be around Graham county around 11pm CT. The overall amount
of people out may be less and its not impacting any school
releases but again the potential for a quick dusting to an inch
of snow due to snow rates around 1 inch per hour will remain.
With the drop in temperatures overnight to below freezing when
this occurs this increases the concern for more roadway issues
as most roads may be below freezing allowing for better sticking
of snowfall to the roads and slick spots and may lead to some
slick surfaces for the morning commute.
Wednesday, this system finally moves out and winds become more
southwesterly and less breezy as high temperatures warm into the 50s
under mainly clear skies.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 1206 PM MST Tue Dec 10 2024
The extended period will feature a more progressive pattern which
will be a change from the northwest flow that we have been in for
nearly the past month. Guidance currently does suggest that this
progressive pattern will continue through at least the next week.
For the most part mild temperatures are forecast to continue however
whenever these quick moving systems apart of this progressive
pattern move across the area then some near normal to potentially
below normal temperatures may occur for a day or two before warming
up again. The first of these quick cool down days looks to be
Friday as GEFS ensemble members more favorably show a chunk of
the Arctic air mass east of the area breaking off and lingering
over the area. Overall there are discrepancies on exactly how
cold it will be but with 850mb temperatures ranging from 0 to 10
below linger over the area throughout the day on Friday there
is potential that the entire area may struggle to get above
freezing for the day. As a result I have started trending high
temperatures down due to more ensemble and deterministic
guidance suggesting this.
For precipitation chances overall the forecast remains dry for
now but there are some conditional chances if everything can
come together perfectly. Based on ensemble clusters towards the
latter portion of the period if a compact enough shortwave can
move across the area then our precipitation and snowfall
potential may increase some more at this time my confidence in
this only around 20% as only one of the cluster shows this
potential with a less compact system and even others with more
split flow feature to it which is less favorable for
precipitation.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 409 PM MST Tue Dec 10 2024
For KGLD... VFR conditions are forecast for the period. We are
watching for another round of rain/snow showers this evening
(between 02-09Z) as a final surge of moisture moves in.
Currently have a PROB30 from 03-06Z as this would be the best
chance for a rain/snow shower to move over the terminal.
Otherwise, flurries will be possible until about 13Z. Winds are
forecast to be around 08-12 kts through the period. Winds will
start the period from the northwest, and then shift to out of
the southwest after 12Z. There is a 10% chance for LLWS between
01-06Z if a mini 35kt jet can form as the upper trough axis
swings to the east.
For KMCK... VFR conditions are forecast for the period. Virga
and flurries will remain possible through 13Z, but the best
chances for showers are forecast to be away from the terminal.
Winds are forecast to be around 10 kts or less through the
period, with a chance for winds to go calm/variable after 12Z
tomorrow. Winds will start the period from the northwest, and
then shift to out of the southwest after 12Z. There is a 10%
chance for LLWS between 01-06Z if a mini 35kt jet can form as
the upper trough axis swings to the east.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...Trigg
LONG TERM...Trigg
AVIATION...KAK
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
755 PM CST Tue Dec 10 2024
.KEY MESSAGES...
- Winds out of the west to northwest will gust 30 to 35 mph
Wednesday afternoon and evening. Scattered snow showers (40-50%
coverage) will accompany the strong winds, and wind-whipped
snow could reduce visibility to under a half mile at times.
Snowfall looks to be generally under an inch.
- Temperatures will fall into the single digits and teens
Wednesday night into Thursday morning with wind chill values
zero to 10 below zero, mainly north of I-72.
- Additional snow is possible again Thursday afternoon and
evening, mainly north of I-72. Snowfall looks to be around an
inch or less.
- There is a slight chance (20%) for light freezing rain or
freezing drizzle briefly Friday morning before precipitation
transitions to rain.
&&
.UPDATE...
Issued at 755 PM CST Tue Dec 10 2024
Latest surface map shows the Arctic cold front back across South
Dakota, while water vapor imagery shows an upper wave advancing
across Iowa and northwest Missouri. This latter feature is
resulting in some snow showers, which the latest HRRR suggests
could reach west central Illinois by 3 am and I-55 toward 7 am.
The front itself is progged to move across the forecast area mid
to late morning, with a line of snow showers behind it. HRRR and
RAP guidance continue to point to around 100 J/kg of surface CAPE,
which would enhance some of the heavier showers. Concern remains
for squalls, with high snow squall values, HRRR visibility below a
mile in the heavier showers, and wind gusts increasing to around
30-35 mph with rapidly falling temperatures. On average, snow
amounts around a half inch are expected, locally heavier depending
on where the showers track. Some adjustments have been made to
the starting time of the snow chances, but the overall trend is on
track.
Geelhart
&&
.DISCUSSION...
Issued at 248 PM CST Tue Dec 10 2024
Lows look to reach the mid 20s tonight as a cool air mass remains
over central IL, with another cold front, currently moving into the
northern Plains, approaching overnight. This front should bring
potential for scattered snow showers across the area Wednesday, with
a potential transient linear frontogenetically forced band. Winds
should gust to around the 30-35 mph range Wednesday afternoon along
with the snow showers, while surface-based CAPE of around 50 J/kg to
possibly 100 J/kg could promote some briefly intense snow showers.
The NAM snow squall parameter continues to show values of 1 to 5 in
this regime. Light snowfall amounts are likely, under an inch in
general, but HREF ensemble system indicates a few showers could
result in localized maximum snowfall corridors exceeding an inch.
Likewise, modeled visibility indicates some localized under 1/2 mile
visibility in the more intense showers. Highs look to range from
around 30 in Galesburg to 38 in Lawrenceville.
Bitter cold air will continue to flow into the area Wednesday night
into Thursday in northwesterly flow, with lows reaching the
single digits north of I-72 to teens to the south. Winds will be
diminishing Wednesday night, but 5-10 mph continuing into early
Thursday morning should result in below zero wind chills mainly
north of I-72, and single digits to the south.
Models have become fairly consistent with developing a
frontogenetical band of snow Thursday across central or northern
parts of IL, and have increased PoPs to as high as 60 percent north
of I-72 Thursday afternoon. Amounts could exceed an inch if this
band stays stationary enough for a long enough time. Temperatures
should remain quite cold, with highs upper teens to lower 20s north
of I-72, ranging only up to lower 30s south of I-70.
Another upper level trough looks to cross the Plains Friday and
slowly move across the Midwest Friday night into Saturday night, as
it deepens a surface low. Rain looks to develop on Friday, likely
late enough that warming temperatures keep precipitation type as all
rain across central IL, but this will have to be watched as an early
arrival could result in some initial freezing rain. Rainfall looks
to be widespread, and model consensus brings amounts of half to 3/4
inches across central and southeast IL at this point. Highs look to
trend upward to upper 30s to mid 40s Friday, 40s Saturday and
Sunday, and around 50 by Monday.
37
&&
.AVIATION... (For the 00z TAFs through 00z Wednesday Evening)
Issued at 530 PM CST Tue Dec 10 2024
Some lingering ceilings below 2000 feet continue over eastern
Illinois early this evening, but will be moving out of KCMI
through 01Z.
Main aviation concern will be with the arrival of an Arctic cold
front Wednesday morning, producing strong westerly winds gusting
20-30 knots through the afternoon. Ceilings expected to lower to
just over 1,000 feet by mid morning at all sites. Scattered snow
showers will accompany the cold air, locally intense but short
lived. HREF probability of visibility below 2SM with these showers
runs around 30-40%, focused on the 14-19Z time frame. However, it
will be difficult to pin down exact placement this far out, so a
PROB30 group for IFR ceilings/visibilities was included at all
sites. Clouds should scatter out mid to late afternoon.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
857 PM CST Tue Dec 10 2024
.KEY MESSAGES...
- A strong arctic cold front will move through Wednesday
afternoon and evening, likely accompanied by gusty snow
showers/squalls. Brief but sudden drops in visibility and a
quick coating of snow may result in hazardous travel during
the PM commute.
- Temperatures quickly plummet behind the front with widespread
-10 to -20F wind chills expected by midnight Thursday morning.
- Confidence is growing in a brief period of snow Thursday
afternoon and evening, primarily south of I-80. Snow
accumulations will be possible.
- A storm system will move across the region late Friday into
Saturday bringing rain, snow, and even some freezing rain to
the area. There is quite a bit of uncertainty regarding this
system.
&&
.UPDATE...
Issued at 857 PM CST Tue Dec 10 2024
Made some minor changes to the going forecast into Wednesday
morning, mainly to add flurries over the City this evening, and
area-wide into early Wednesday.
Evening upper air analysis and GOES vapor imagery depict a
deepening long wave upper level trough across the central
CONUS/NOAM. Several smaller scale short waves were noted within
the trough, including a shearing mid-level vort lifting
northeast across MO/IL/LM/MI, another wave tracking ESE across
IA and adjacent parts of MN/MO, and a digging wave crossing the
International border into eastern ND/northwest MN. AMDAR
aircraft soundings, 00Z RAOBs and RAP initialized soundings
depict a rather shallow moist/cloud layer across the region this
evening, roughly between 2000-6000 ft. While no organized
precip was occurring from this deck locally, we have been noting
what appears to be aircraft-induced flurries near and downwind
(to the ESE) from O`Hare, as the top of the cloud layer is
near -10C for ice nucleation. Not expecting anything
significant with this. Farther to the west across central IA,
radar and surface obs do indicate some patchy light snow
associated with the aforementioned short wave. This should work
its way east- southeast into western IL during the pre-dawn
hours, with the potential for at least some flurries spreading
across the cwa before snow showers overspread the region during
the remainder of the morning hours. Thus have added flurries
near/downwind of ORD this evening, and spread flurries into the
entire forecast area from west-east from about 3 am onward. Did
increase pops for snow showers across our far west/southwest
counties toward sunrise.
No significant changes made beyond Wednesday morning at this
point, with snow showers/squalls and rapidly dropping
temperatures behind an arctic cold front beneath the digging
ND/MN vort during the midday and afternoon hours. Strong low-
level cold advection, temperatures falling quickly into the
teens/low 20s (from morning highs near 30), steepening low-
level lapse rates (~8 C/km), and enhanced frontogenetic forcing
all point to scattered to numerous snow showers/squalls from
midday/early afternoon into early evening, with blustery west
winds gusting 35-40 mph (possibly slightly higher in more
intense snow showers). Going forecast appears to have this well
in hand at this point, thus no changes made for now.
Ratzer
&&
.DISCUSSION...
Issued at 300 PM CST Tue Dec 10 2024
Through Thursday Morning:
Focus in the near term is on the anticipated arctic air
intrusion accompanied by a period of gusty snow showers/squalls
on Wednesday and subsequent dangerous wind chill values of -10
to -20F into early Thursday morning.
Cooler conditions continue today with widespread cloud cover
and continued steady cold air advection into the region has held
temperatures in the 30s this afternoon. Interestingly, a few
aircraft induced flurries have been observed around O`Hare at
times this afternoon as planes fly through the low cloud deck.
Temperatures tonight are forecast to drop into the 20s, though
locally colder temperatures are possible if breaks in the clouds
manage to occur.
The high temperature on Wednesday could actually end up
occurring late morning immediately ahead of the much anticipated
strong arctic cold front expected to reach northwest
Illinois/Rockford area toward midday and quickly push across the
rest of Chicagoland into northwest Indiana through the
afternoon. This front will likely be accompanied by a period of
gusty snow showers and potentially a dangerous snow squall. Hi-
res guidance continues to suggest conditions will be conducive
for snow squalls. The RAP highlights well the potential for a
narrow axis of low-level frontogenesis to develop with the front
coinciding with steep low-level lapse rates along with a modest
3-hr surface pressure rise/fall couplet on either side of the
front. This could aid in enhancing wind gusts within this fgen
band locally up to 40-45 mph.
A lingering question remains when these "ingredients" all come
together, with the snow squall parameter increasing as the front
approaches the I-55/57 corridors into northwest Indiana. While
the Rockford area is not fully out of the woods, it is possible
coverage is lower west of the Chicago metro. If this scenario
plays out, the snow showers/squall may be developing as the
front moves into the Chicago metro. Regardless, all areas of
northern Illinois and northwest Indiana will want to be prepared
for a brief period of sharply reduced visibility in
snow/blowing snow and a quick coating on roadways resulting in
slick travel during the afternoon/evening commute.
To put this round of possible snow showers/squalls into
perspective compared to last week`s, surface temperatures will
already be below freezing (which were too warm last week for a
more robust initial snow squall with the front) and would
support snow readily accumulating on roadways. However, the
pressure gradient is not as strong, with peak wind gusts
currently expected to remain in the 40- 45 mph range versus the
55-60mph wind gusts observed last week. Nevertheless, multiple
hi-res models depict localized visibility reductions as low as
1/4 mile within these snow showers/squalls.
Temperatures are forecast to quickly plummet in the wake of the
arctic frontal passage and associated snow showers/squalls with
temperatures quickly dropping into the single digits through
the evening with overnight low temperatures in the 0 to +7
degree range. With continued wind gusts in the 30-40 mph range,
expect bitterly cold minimum wind chills around -10 to -20
degrees overnight into early Thursday morning.
Petr
Thursday Afternoon through Tuesday:
For Thursday afternoon and evening, the issue of concern would
be a band of light snowfall across the southern half of the
forecast area, especially in a corridor from LaSalle County into
Iroquois and Benton counties. This would be along the leading
edge of a baroclinic zone associated with a broad region of warm
advection, assisted by an area of reduced midlevel stability as
well as divergence aloft in the right entrance region of the
upper jet. QPF amounts are modest given the limited moisture,
but considerable Fgen forcing and large snow-to-liquid ratios in
the very cold air could result in a band of around one inch of
accumulation. Given afternoon highs in the teens following
single digit lows Thursday morning, every flake that falls is
likely to stick on the cold roads.
Attention then turns to the next system moving through later
Friday into Saturday which will bring a more prolonged period of
precipitation. Models are in rough agreement showing a surface
low deepening in the lee of the Rockies then moving out of the
Plains and nearly overhead Saturday night while gradually
weakening. It is still too early to pin down any exact precip-
type evolution, but rain, snow, and possibly a brief period of
freezing rain are all in play. The good news is that temperature
trends are generally increasing throughout the period, with
highs Saturday in the lower 40s, so wintery impacts should be
limited, especially after Friday night. Even on Friday night,
our northernmost areas most likely to see an initial onset of
snow will probably transition to rain by morning.
After precipitation moves out Saturday evening, height rises
aloft should help keep Sunday cloudy but dry compared to
Saturday, with similar highs in the lower 40s. The gradual
warming trend then continues into early next week with highs
Monday in the upper 40s...and possibly lower 50s south. Some
models are then showing a weak cold front that looks to drop
temperatures back to the lower 40s for Tuesday, and which could
be accompanied by another round of precipitation in the form of
rain.
Lenning
&&
.AVIATION /00Z TAFS THROUGH 06Z THURSDAY/...
Issued at 600 PM CST Tue Dec 10 2024
Forecast concerns for the terminals...
- Gradually improving ceilings tonight, but a return to MVFR
conditions Wednesday morning
- Cold front to bring gusty snow showers Wednesday afternoon and
evening resulting in sharp changes in visibility
- Gusty west-northwest winds Wednesday afternoon and evening
upwards of 30 kts
MVFR ceilings continue to reside overhead this evening ahead of
an upper trough that is pivoting into the Great Lakes. While the
ceilings should continue to lift into the 3500-4000 ft range by
midnight, BKN to OVC skies are expected to prevail overnight
with pockets of MVFR clouds as well.
Heading into Wednesday, the MVFR ceilings are expected to return
towards mid-morning as the center of the aforementioned trough
slides overhead and moisture begins to pool ahead of a strong
arctic cold front. This front will move through the terminals
Wednesday afternoon resulting in the development of scattered
snow showers and perhaps even a few snow squalls through the
early evening hours. Given the combination of broad forcing and
decent low-level instability, these snow showers/squalls will be
capable of producing sharp changes in visibility (in the 1-2 SM
range) in addition to quick accumulations as temperatures
plummet behind the front. Due to the progressive nature and
limited coverage of the showers/squalls, accumulations should
generally be below 0.5 inches but locally higher amounts are
possible with the strongest showers.
Otherwise, expect winds to also increase behind the front with
gusts in the 25-30 kt range expected through Wednesday evening.
The aforementioned MVFR ceilings will quickly scatter out
Wednesday evening as much drier air behind the front pivots into
the area and persists through the end of the period.
Yack
&&
.MARINE...
Issued at 300 PM CST Tue Dec 10 2024
- Gale Warning issued WED afternoon through early THU morning.
- Heavy Freezing Spray Warning issued for NW Indiana nearshore
waters WED night through early THU morning.
A powerful arctic front is expected to race across the Lower Great
Lakes Wednesday afternoon causing northwesterly winds and gusts to
quickly increase in magnitude, with a period of 35 to 40 kt gales
expected through early Thursday morning.
In addition, the combination of tumbling temperatures toward the
single digits and gale force winds may lead to heavy freezing
spray Wednesday night into Thursday morning, particularly east
of Gary, Indiana.
Petr/Borchardt
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Gale Warning from 2 PM Wednesday to 6 AM CST Thursday for
Winthrop Harbor IL to Gary IN.
Gale Warning from 3 PM Wednesday to 9 AM CST Thursday for Gary
to Burns Harbor IN-Burns Harbor to Michigan City IN.
Heavy Freezing Spray Warning from 9 PM Wednesday to 9 AM CST
Thursday for Gary to Burns Harbor IN-Burns Harbor to
Michigan City IN.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
541 PM CST Tue Dec 10 2024
.KEY MESSAGES...
- Isolated to scattered snow showers are expected on Wednesday,
mainly in the morning and early afternoon. An isolated snow
shower or two may briefly produce moderate to heavy snow,
reducing the visibility and producing up to 1/2 inch
accumulations on grassy and elevated surfaces.
- Periods of rain are expected beginning on Friday afternoon and
continuing through Saturday afternoon.
&&
.SHORT TERM... (Through Late Wednesday Afternoon)
Issued at 240 PM CST Tue Dec 10 2024
The primary forecast concern in the short term is the potential for
snow showers on Wednesday. A long wave mid-upper level trough is
digging into the Great Plains this afternoon. The trough moves east
tonight into the Mississippi Valley by 12Z Wednesday. The low level
reflection of the wave is subtle, but guidance is showing a
definite thermal ridge just ahead of the wave, and a thermal
trough behind it. This pattern produces transient waves of weak to
moderate low level frontogenesis over Missouri and Illinois
through the day. Forecast soundings show all the moisture in the
column below 800mb, but very steep low level lapse rates,
resulting in a small amount of CAPE (<75 J/kg) by mid to late
Wednesday morning. Between the broad-scale lift from the trough
and the low level frontogenesis, there should be enough forcing to
produce some snow. All indications are that the snow will be
showery in nature, and while I would expect much of the area to
see a little light snow or some flurries, there will likely be a
few heavier snow showers concentrated along the waves of
frontogenesis. Indeed, the HRRR is showing a few snow showers with
simulated reflectivity up to 40- 45dBZ. While the snowfall rates
in these stronger showers may be fairly high, the showers will be
moving quickly so they won`t last long over any one location. A
quick 1/2 inch of accumulation isn`t out of the question where
these showers track, but pin-pointing the location is impossible
at this time. Ground temperatures remain warm with 2 inch soil
temperatures mainly in the mid to upper 30s so accumulations
should be limited to grassy and elevated surfaces. Lastly, winds
are expected to increase to 15-20mph with gusts as high as 30mph
by mid-late morning. Blowing snow in the stronger showers combined
with these winds will be capable of quickly dropping visibilities
to 1/2 mile or less. Another reinforcing shot of very dry Arctic
air will dive into Missouri and Illinois on northwest flow
Wednesday afternoon and evening and this will bring an end to the
chance for precipitation.
Carney
&&
.LONG TERM... (Wednesday Night through Next Tuesday)
Issued at 240 PM CST Tue Dec 10 2024
Low pressure begins developing early Thursday over the western
Plains in response to a weak and fast-moving short wave aloft. This
turns the low level flow back to the south across the lower
Mississippi Valley and the southeast Plains. Most deterministic
guidance shows the resulting warm front moving as far north as I-70
in Missouri and I-64 in Illinois before stalling. Temperatures on
Thursday will be determined by the position of the front, and the
difference between the LREF 25th and 75th percentile is 7-10
degrees. Needless to say, confidence in Thursday`s temperature is
low. Models are now producing a band of snow across parts of Iowa
and central Illinois due to the strong warm advection over the
front. I mention this because there are a few members of the LREF
that keep the front farther to the south which would push the band
of snow into northeast Missouri and west central Illinois. 90+
percent of the members are dry...but there is an outside chance our
far northern CWFA could see precipitation on Thursday.
The next short wave moves off the Rockies on Friday which finally
pushes the warm front north into Iowa. Strong warm advection ahead
of the attendant surface low will produce periods of precipitation
most likely beginning Friday afternoon and continuing until the cold
front moves through late Saturday afternoon or Saturday night.
Temperatures still look warm enough for all of the precipitation to
remain liquid. Relatively mild temperatures continue Sunday through
Tuesday with another potential shot of rain Monday into Monday night.
Carney
&&
.AVIATION... (For the 00z TAFs through 00z Wednesday Evening)
Issued at 452 PM CST Tue Dec 10 2024
VFR conditions will prevail through tonight. Snow showers will
pass through the forecast area from northwest to southeast, with
flurries possible for all locations outside of southeast Missouri.
This system will bring MVFR ceilings to portions of northeast
Missouri, west-central Illinois, and portions of south-central
Illinois. The heaviest snow showers may be capable of briefly
producing IFR visibilities and snow accumulations on elevated and
grassy surfaces. Wind gusts of up to 25+ kts beginning mid-morning
will be capable of blowing this snow around, potentially resulting
in additional visibility restrictions.
Jaja
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Melbourne FL
919 PM EST Tue Dec 10 2024
...New UPDATE...
.KEY MESSAGES...
Issued at 416 PM EST Tue Dec 10 2024
- Scattered to numerous showers and isolated lightning storms
capable of wind gusts up to 40-50 mph are forecast on Wednesday
as a cold front moves southeast over east central Florida
- Temperatures drop into the 30s and 40s on Thursday behind a cold
front passage Wednesday, with patchy frost forecast across the
north Thursday morning
- Hazardous conditions are expected to develop over the local
Atlantic midweek, with a Moderate to High risk of rip currents
expected to continue at area beaches, in addition to High Surf
into late week
- Breezy to windy southwest winds are expected Wednesday before
veering north on Thursday with sensitive fire weather conditions
forecast behind a cold front
&&
.UPDATE...
Issued at 912 PM EST Tue Dec 10 2024
Our anticipated cold front is working its way into the far western
Florida panhandle as of around 9PM this evening. Locally, cirrus
continues to increase over the area.
No major changes to the forecast this evening. The HRRR continues
to suggest a few showers will be possible after midnight along
the coast and from around Melbourne/Kissimmee northward. Thus,
have maintained the 20% chance of showers overnight. Otherwise,
east central Florida looks to remain mostly dry through daybreak.
Winds will begin to increase towards sunrise to around 10mph, as
the front nears the local area. Overnight lows will be noticeably
above normal compared to the previous few days, staying in the
mid 60s.
&&
.PREVIOUS DISCUSSION...
Issued at 416 PM EST Tue Dec 10 2024
Currently-Wednesday... Local radar imagery shows mostly dry
weather over east central Florida with a few of light sprinkles
over the Treasure Coast Atlantic waters. GOES-16 satellite imagery
shows partly cloudy to partly sunny skies. High pressure (~
1026mb) is centered near Bermuda over the western Atlantic.
Current temperatures are in the mid 70s to low 80s with dew points
in the upper 50s to mid 60s. Winds are generally from the south-
southeast at 10-15mph with gusts to 25mph.
Dry weather is forecast through this evening and into the
overnight hours. South-southwest winds are expected to veer north-
northwest into Wednesday afternoon at around 15 to 20 mph with
gusts up to 30-35 mph as a cold front moves southeast over east
central Florida. South-southwest winds are expected to veer west-
northwest into Wednesday afternoon at around 15 to 20 mph with
gusts up to 30-35 mph as a cold front moves southeast over east
central Florida. Scattered to numerous showers (PoPs ~ 40-70%)
and isolated to widely scattered lightning storms are forecast to
develop along and ahead of the aforementioned cold front on
Wednesday with the greatest chance for rain and storms to the
north of I-4 Wednesday morning and to the south into the afternoon
before rain chances diminish Wednesday night over the Treasure
Coast. Hi-res guidance shows MLCAPE between 600-1,200
J/kg, conditionally unstable mid level lapse rates (~6.0-7.5
C/km), and 0-6km bulk shear at 30-40kts, in addition to a
southwest LL jet at 30-50kts. Isolated storms will be capable of
occasional lightning strikes, wind gusts up to 40-50 mph, and
moderate to locally heavy rainfall. Afternoon highs in the low to
mid 70s are forecast north of I-4 with the mid 70s to low 80s to
the south on Wednesday.
Thursday-Friday... Cold temperatures are expected behind the cold
front Thursday morning with lows in the mid 30s to low 40s along
and north of I-4 with the low 40s to near 50 degrees to the south.
North winds will combine with cold temperatures and result in
minimum Wind Chill values in the low 30s north of I-4 with the
low 30s to mid 40s to the south Thursday morning. Mostly dry
weather is forecast Thursday and Friday as high pressure (~
1028mb) builds over the Deep South on Thursday and to the north of
central Florida (~ 1036mb) over the eastern CONUS on Friday.
Breezy north winds at 10-20mph with gusts up to 25-30mph are
forecast on Thursday. North winds are forecast to veer east-
northeast on Friday at 15 to 20 mph with gust up to 25-30mph.
Isolated (PoPs ~ 20%) showers are forecast over the local Atlantic
Waters into Friday afternoon, as well as along and east of I-95.
Mostly sunny to partly cloudy skies are expected Thursday with
partly cloudy to partly sunny skies on Friday.Lows in the low 40s
are forecast to the north of I-4 Friday morning with the mid 40s
to mid 50s to the south and to the Treasure Coast with the mid 50s
to near 60 degrees forecast over the Treasure Coast. Afternoon
highs in the low to mid 70s are forecast Friday with breezy east-
northeast winds at 10-20mph and gusts to 25-30mph.
Saturday-Monday... Onshore flow is expected to continue into the
weekend as high pressure (~1040mb+) builds to the north over the
northeastern CONUS into the weekend. Winds are expected to back
north at 10-15mph into Sunday. Isolated to scattered (PoPs
generally ~ 20-50%) showers are forecast over the local Atlantic
waters and mainly to the east of the Orlando metro (PoPs ~
20-30%) Saturday afternoon and through the weekend (greatest
potential into the afternoons) with partly cloudy to partly sunny
skies. Afternoon highs in the mid 70s to low 80s are forecast
Saturday and Sunday with the low to upper 70s forecast on Monday.
Lows in the mid 50s to mid 60s are forecast.
&&
.MARINE...
Issued at 325 PM EST Tue Dec 10 2024
Currently-Wednesday... Poor boating conditions are expected to
become hazardous late tonight into Wednesday as a cold front moves
southeast over the local Atlantic waters on Wednesday. Southerly
winds will increase to 20-25 kts with occasional gusts up to
35kts into Wednesday before veering north behind the front late
Wednesday into Thursday. Scattered to numerous showers and
isolated lighting storms are forecast to move southeast across
the waters Wednesday. Isolated storms will have the potential to
produce occasional lightning strikes, wind gusts up to
40-50mph, and moderate to locally heavy rainfall. Seas are
forecast to build to 3-5ft with up to 6-7ft over the Volusia and
Brevard county offshore (20-60nm) waters. A Small Craft Advisory
goes into effect for the offshore Volusia waters at 3 AM Wednesday
expanding southward across offshore Brevard and eventually the
offshore Treasure Coast by 10 AM.
Thursday-Saturday... Hazardous boating conditions are expected to
continue Thursday and into the weekend. Dry conditions are
expected on Thursday with isolated showers (PoPS ~ 20%) forecast
Friday afternoon and isolated to scattered showers (PoPs ~20-50%)
on Saturday. Northerly winds decrease into Thursday afternoon at
15-20 kts and veer east into Friday at around 20-25kts with gusts
up to 34kts. Seas are forecast to build to 5-8 ft with seas to
9-10 ft over the Gulf Stream on Thursday and through Saturday.
&&
.AVIATION...
(00Z TAFs)
Issued at 649 PM EST Tue Dec 10 2024
VFR conditions prevailing overnight. A strong cold front is
forecast to push southward through the Florida peninsula
Wednesday. Winds will begin to increase for areas along and north
of the I-4 corridor around daybreak, with showers possible into
the late morning hours. Then, a line of showers and thunderstorms
will pass through the terminals beginning early in the afternoon
(15Z) for LEE/DAB, leading to MVFR CIGs and possible VIS
reductions in heavier showers and storms. Have forgone including
TEMPOs at this time, but will continue to monitor timing for
TEMPOs as the front approaches. The front will continue southward,
with conditions improving behind it, clearing the Treasure Coast
in the evening (23Z) and veering southerly winds to the northwest.
Gusty winds will precede and accompany the cold front. Wind gusts
of 25-30kts are expected area-wide.
&&
.FIRE WEATHER...
Issued at 416 PM EST Tue Dec 10 2024
Thursday... Sensitive to near critical RH values are forecast on
Thursday mainly to the north of I-4 with minimum RH values in the
low 40s. Breezy north winds at around 10-20mph and gusts to
25-30mph are forecast with dry conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 64 79 39 62 / 20 60 10 0
MCO 65 78 43 64 / 20 60 10 0
MLB 65 82 43 68 / 20 60 10 0
VRB 65 83 45 70 / 10 60 20 0
LEE 64 77 38 62 / 20 60 10 0
SFB 65 79 41 63 / 20 60 10 0
ORL 65 79 42 64 / 20 60 10 0
FPR 65 84 45 70 / 10 60 20 0
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 4 PM Wednesday to 10 AM EST Thursday
for AMZ550-552.
Small Craft Advisory from 7 PM Wednesday to 10 AM EST Thursday
for AMZ555.
Small Craft Advisory from 3 AM Wednesday to 10 AM EST Thursday
for AMZ570.
Small Craft Advisory from 7 AM Wednesday to 10 AM EST Thursday
for AMZ572.
Small Craft Advisory from 10 AM Wednesday to 10 AM EST Thursday
for AMZ575.
&&
$$
UPDATE...Leahy
AVIATION...Leahy
Area Forecast Discussion
National Weather Service New York NY
949 PM EST Tue Dec 10 2024
.SYNOPSIS...
A stationary front lifts north as a warm front late tonight
into Wednesday morning. A strong frontal system will affect the
area Wednesday into Wednesday night. A secondary cold front
moves through Thursday, followed by strong high pressure
building over the region into the weekend. A weakening
disturbance approaches late in the weekend, before another
frontal system potentially impacts the area early next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Forecast on track with just minor adjustments to reflect current
observations. Low stratus and patchy areas of fog across the
region early this evening. Light rain continues to develop just
ahead of a slow moving frontal boundary over eastern PA and NJ,
and this activity will expand and spread east over the next
several hours.
Anomalous, longitudinally deep trough digs down to the Mississippi
Gulf coast tonight, with deep SW upper flow ahead of it tonight.
At the surface, a series of southerly lows track north along a
stationary cold front running from the Gulf coast into the Ohio
valley/Great Lakes, with a warm front slowly working north
towards the region overnight. The warm front will lift north
late tonight into early Wed AM, as a coastal llj strengthens and
expands north into the region.
E/NE flow to the north of the approaching warm front will maintain
low clouds and patchy fog/drizzle into the first half of
tonight, with increasing likelihood of showers overnight into
early Wed AM with WCB approaching the region and a deep layered
lift of a +3-4 STD PWAT airmass over the region.
Evening low temps from the lower 40s to near 50 should increase
through the 50s for the coast, while holding in the mid to upper
40s across interior valleys overnight.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Anomalous, longitudinally deep trough digs down to the
Mississippi Gulf coast Wed AM, negatively tilts and pivots into
the Mid Atlantic Wed eve, and then across the area Wed Night.
At the surface, warm front lifts north Wed AM, with a series of
low pressure waves tracks north along the eastward moving cold
front approaching the region Wed AM into aft, and then crossing
Wed eve.
Initial area of moderate to heavy rain associated with head of
strengthening llj and northward moving warm front may briefly
subside in the late AM/early afternoon for western areas, while
potential for this to continue for LI/S CT under strengthening
llj.
This will be followed by main axis of moderate to heavy
rainfall associated with deep layered lift (divergent flow ahead
of vigorous upper trough axis and under right front quad of
150kt ulj) and strong moisture convergence and lift ahead/along
approaching cold front in the aft/early eve as a result of a
weakly unstable +3-4 STD PWAT airmass being advected in on a
75-80kt llj. Embedded tstm activity possible as a weakly
unstable airmass advects into the region.
High-res cams indicating a fine line of low-topped convection
likely organizing along the cold front, although timing
differences on how quickly the line gets organized across areas
w of NYC. Generally moving from w to e across the region
between noon and 8pm. Higher model confidence in this line
consolidating across LI/S CT. Rainfall rates of 1+"/hr possible
with this line. A few hours of post-frontal moderate rain likely
behind the front before coming to an end Wed eve. Overall, a
general 2-3" of rain likely areawide, with locally 4-5" possible
across LI/S CT if/where most persistent banding develops.
Overall, primary threat is for minor urban, poor drainage and
even small stream flooding, so no Flood watch issuance at this
time. See hydro sections for rainfall details and potential
flood impacts.
The 75-80 kt llj overspreading the coast Wed aft into early
eve, combined with only a weak low-level inversion will present
potential for damaging wind gusts across LI and SE CT, with wind
advisory winds gusts for the remainder of the coastal plain,
including NYC. BUFKIT analysis and HRRR wind gust potential
support a high wind warning for LI, coastal New Haven, and
Middlesex and New London counties for 55 to 60 mph gust
potential (localized 65mph gusts possible for east end of LI),
50 to 55 mph gusts potential for the next tier of counties
inland. Winds shift to the W with cold frontal passage Wed
evening, and continue gusty with cold advection (25-35 mph,
locally 40 mph, much of the night)
Unseasonably mild temperatures of 60-65 on Wed should quickly drop
after cold fropa Wed evening, with lows in the lower 30s by
daybreak Thu.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Key Points...
* Sharply colder behind midweek system, wind chills in the 20s
Thursday and Friday afternoon
* Turning milder and unsettled early next week as a frontal system
potentially impacts region
Strong CAA follows the cold frontal passage into Thursday, with a
secondary front moving through late in the day. The parent low
pressure deepens as it tracks into Quebec, and surface high pressure
begins to build in from the west. This tightened pressure gradient
will keep a strengthened flow in place. The cold air aloft should
allow mixing toward 850 mb, keeping conditions blustery through the
day with westerly gusts 30 to 40 mph. With 850 mb temps progged
around -11C to -13C, afternoon temperatures should only achieve the
mid 30s inland to the lower 40s for eastern areas. With the gusty
conditions, expect wind chills in the 20s through the day, if not
lower. Absent a stray flurry in the interior, conditions remain dry
under mostly sunny skies.
Winds weaken by Friday as the center of the high approaches.
Sunshine prevails, but conditions remain colder than normal with
highs only in the low to mid 30s and morning wind chills in the
teens. The strong 1047 mb surface high passes just north of the
local Tri-State into Saturday, and the flow veers around and becomes
onshore by Sunday as the center slips into the Canadian Maritimes.
This will help nudge temperature up from the 30s and 40s Saturday to
the 40s and low 50s Sunday. Increasing low level moisture with the
flow should lead to a good amount of lower clouds on Sunday as a
weak mid level wave and warm front approach, though it remains
unclear if the associated precip dissipates before reaching the
area. Another frontal system may move through early next week, but
guidance disagrees with timing and intensity. Kept PoPs capped at
chance (50%) for now until the picture becomes clearer, but at this
time the first few days of next week appear unsettled. Left ptypes
at rain and/or snow at this stage, but more likely would be either
all rain or perhaps a wintry mix well inland based on soundings and
warmer air moving in aloft.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A frontal boundary south of the terminals slowly lifts north
tonight. Low pressure and its associated cold front approach
overnight. LIFR and IFR prevail through tonight with ceilings
remaining below 1 kft, and in most cases below 500 ft. Some
pockets of reduced visibility at a few terminals in fog can
also be expected. Rain spreads west to east across the
terminals tonight and will continue through much of the day
Wednesday. Some of the rain may be heavy at times. Can not rule
out a rumble or two of thunder, however confidence on timing and
placement too low to include in the TAFs at this time.
Winds become SE-S overnight. Gusts develop around daybreak along
with the potential for LLWS for city and western most terminals.
By 12-15z LLWS should prevail at most terminals as gusts get to
30 kt by 15z, and approach 35 to 45 kt for the city and eastern
terminals towards 18z. Winds start to peak out closer to 21z
with gusts as high as 50kt.
NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
Amendments can be expected through much of the TAF period for
differing flight categories, changing wind directions and wind
gusts.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
Wednesday night: Winds become more west overnight with VFR
returning towards midnight and gusts still around 30kt.
Thursday: VFR with W winds 15-20G30kt.
Friday and Saturday: VFR.
Sunday: sub VFR possible in light rain and low clouds, especially
late.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Sub SCA conds into tonight.
Low pressure and its associated cold front will impact the
waters Wed into Wed evening. Southerly winds and ocean seas will
quickly increase to SCA early Wed AM, and then Gales by midday
Wed. As strong LLJ moves across a period of storm force wind
gusts are likely across most waters, except NY harbor. Rough
seas are expected with this system, up to 4-7 ft on the Sound
and 12-18 ft on the ocean late Wednesday into Wednesday night.
Once the strong low level jet passes Wed eve, westerly gales
are expected in its wake Wed Night into Thu Am.
Gales are likely to continue through Thursday afternoon on at
least the ocean, and potentially on the non-ocean waters. Winds
lower below 25 kt on all waters by Thursday night and ocean seas
gradually lower from over 10 ft Thursday morning, to under 5 ft
by late Friday morning. Sub SCA conditions then persist on all
local waters Friday into early next week.
&&
.HYDROLOGY...
A widespread 2-3" of rainfall likely from late tonight into Wed
evening ranges from 2-3 inches. Locally 4 to 5" amounts are
possible across LI/S CT where high-res models are indicating
bands of heavy rain persistently moving north thru the region
late tonight into early Wed aft, and followed by a consolidating
e-w moving axis of heavy rain/embedded thunder ahead/along the
cold front.
Rainfall rates of 1+"/hr possible in this line. This line will
be progressive, but will occur over already saturated ground
from earlier 1-2" rain over LI/CT and may expand in size as it
moves east with better llj forcing.
Headwater guidance indicating that 2"/6hr or 3"/12hr would be
sufficient for minor flashy small stream flooding. Moderate
potential of this occurrence is across S CT.
Otherwise, the primary threat from this rainfall will be minor
urban and poor drainage flooding, with rainfall rates of
generally 1/4 to 1/2"hr between 6am and 6pm, with brief
3/4-1"/hr rates possible. This will be most persistent across
LI/S CT. There is a localized risk of flash flooding where
higher rates persist, particularly S CT.
&&
.TIDES/COASTAL FLOODING...
As little as 1 1/4 to 1 1/2 ft surge needed for minor coastal
impact with the Wed AM high tide. With as little as 2 1/2 ft for
the evening high tide.
With easterly flow tonight causing some tidal piling, and
southerly winds just beginning to ramp up during the morning
high tide, water levels will approach minor flood thresholds and
perhaps touch in a few spots across SW CT and southern
Queens/Nassau.
While peak surge is expected to occur Wed afternoon and early
evening, stillwater levels for most locations should once again
remain below minor flooding benchmarks. But with a gradual
windshift from southerly storm force to SW SCA just before or
during the time of evening high tide, potential for areas along
the southern bays of NYC LI, south facing shoreline of twin
forks, and coastal CT to see minor coastal impacts from combo
of elevated water and splashover from wave action. This includes
the eastern Great South Bay as water levels may remain elevated
and could touch minor benchmarks as a strong southerly flow
switches to the southwest, preventing water from escaping the
bay quickly.
The combination of 10-15 ft breakers during the evening high
tide will cause widespread beach flooding and erosion.
Scattered area of dune base erosion, and localized washovers
possible for LI beaches where dunes protection is compromised.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory from noon to 10 PM EST Wednesday for CTZ005-006-
009.
High Wind Warning from noon to 10 PM EST Wednesday for CTZ007-
008-010>012.
NY...Wind Advisory from noon to 10 PM EST Wednesday for NYZ071>075-
176-178.
High Wind Warning from noon to 10 PM EST Wednesday for
NYZ078>081-177-179.
NJ...Wind Advisory from noon to 10 PM EST Wednesday for NJZ006-104-
106-108.
MARINE...Storm Warning from noon to 10 PM EST Wednesday for ANZ331-332-
335-340-345-350-353-355.
Gale Warning from 6 AM Wednesday to 6 AM EST Thursday for
ANZ338.
&&
$$
SYNOPSIS...NV
NEAR TERM...BC/NV
SHORT TERM...NV
LONG TERM...DR
AVIATION...BC
MARINE...DR/NV
HYDROLOGY...DR/NV
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Phoenix AZ
432 PM MST Tue Dec 10 2024
.UPDATE...
Updated Aviation
&&
.SYNOPSIS...
Cooler temperatures, closer to seasonal normals, can be expected
this afternoon with much of the high terrain and some rural desert
areas locations reaching the freezing mark Wednesday morning. High
pressure will become reestablished over the region resulting in a
slight warming trend through the end if the week and into the
weekend. Dry conditions will prevail over the next several days.
&&
.DISCUSSION...
Current 500mb RAP analysis reveals a highly amplified pattern across
the western half of the United States with ridging over the Pacific
Coast and a positively tilted trough over the Plains. This
disturbance provided the Desert Southwest with some breezy to windy
conditions overnight but any residual breeziness will diminish
through this evening as the trough axis pulls away from our forecast
area. An accompanying cold front as introduced cooler and very dry
air to the region with morning dew point values in the single digits
to even below zero. Temperatures this afternoon across the lower
deserts will be several degrees lower than what was observed
yesterday, with readings ranging generally in the middle 60s,
which is right around normal for this time of year.
With the presence of a much cooler airmass compared to what we have
seen through the first part of December, cold overnight lows can
be expected for Wednesday morning across the region. Add in very
dry air, and minimal wind, and you have a setup that will promote
some of the coldest overnight temperatures seen so far this year.
Middle 30s to lower 40s will be common across lower desert areas
with more rural desert communities likely seeing near to below
freezing values. As a result, a Freeze Warning has been posted for
parts of the Lower Colorado River Valley, portions of the Gila
River Valley in Yuma County, parts of Pinal County, and the
Globe/Miami and San Carols areas in southern Gila County.
Therefore, if residing in these areas under a Freeze Warning, make
sure to practice the 4 P`s which are protect people, pets, pipes,
and plants from the cold.
The aforementioned ridge will eventually encompass much of the
western CONUS by Wednesday which will allow for a slight rebound in
temperatures across the region, but afternoon highs are expected
to remain in the middle to upper 60s for most locations, with the
exception of a few reaching into the lower 70s. Ensembles indicate
a transient short-wave trough diving across the Great Basin on
Thursday, but should not bring any sensible weather changes to
our forecast area as it will likely pass to far to our north. In
the wake of this disturbance, stronger ridging is depicted taking
hold, promoting a further warming trend, with lower desert highs
warming into the middle 70s by this weekend, a good 10 degrees or
so above normal for the middle of December.
&&
.AVIATION...Updated at 2330Z
South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation concerns are expected through the forecast period.
Westerly winds between 04-08kts will continue through most of the
afternoon with an easterly shift by 04Z and will remain through
the night/morning. Speeds should remain light aob 6kts overnight.
Skies will remain mostly clear through the majority of the TAF
period with some high cirrus clouds starting to move in at the end
of the period.
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are anticipated through the forecast period.
Elevated northerly winds will continue this afternoon, where
speeds will be generally be aob 7kts through this evening. Winds
are expected to shift around to the west by 02Z at KIPL and 08Z at
KBLH then back northerly by tomorrow afternoon. Skies will remain
mostly clear through the majority of the TAF period with SCT-BKN
high clouds starting to move in at the end of the period.
&&
.FIRE WEATHER...
Noticeably cooler temperatures closer to seasonal norms are
expected today as highs top out in the mid to upper 60s across the
lower deserts. Some gusty northerly winds will persist through
this morning, mainly along the Colorado River Valley, with some
breezy northeasterly winds across the AZ higher terrain. Winds are
expected to diminish heading into this afternoon and evening.
MinRH values this afternoon are expected to bottom out in the
single digits area wide. Heading into the latter half of the week
and especially this upcoming weekend, temperatures will warm up
into the above normal range once again with generally light winds
expected. MinRHs will be in the single digits to lower teens
Wednesday and Thursday, before rising into the 15-20% range
heading towards the end of the week and into the upcoming weekend.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Freeze Warning from midnight tonight to 9 AM MST Wednesday for
AZZ530-536-553-560-562.
CA...Freeze Warning from 11 PM this evening to 8 AM PST Wednesday for
CAZ569.
&&
$$
DISCUSSION...RW
AVIATION...Ryan
FIRE WEATHER...Lojero
Area Forecast Discussion
National Weather Service Raleigh NC
935 PM EST Tue Dec 10 2024
.SYNOPSIS...
In-situ cold air damming and an associated wedge front will continue
to retreat from northwestern NC into VA tonight. A strong upper-
level trough and accompanying surface cold front will sweep across
the region on Wednesday. Chilly high pressure will build into the
region for Thursday and Friday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 935 PM Tuesday...
* Little change to current forecast reasoning with only minor
adjustments to the forecast with widespread rain spreading across
the area overnight and perhaps a rumble of thunder.
The latest surface analysis shows an approaching cold front
extending from western PA south across WV and into eastern TN and
northern AL. The airmass across central NC is warm and moist with
surface dew points in the lower 60s at 9pm and air temperatures in
the lower to mid 60s. A wedge front marking the edge of a cooler and
less humid air mass has retreated northwest into northwestern NC and
western VA. Further aloft, a vigorous mid and upper level trough is
advancing east across the Plains states with the jet stream diving
south into TC and LA this evening and a strong southwesterly flow
aloft across the Southeast and the Carolinas. The evening RAOB at
KGSO observed a 50kt southwesterly wind at 860mb and 125kts at
260mb. The RAOB also analyses a PW of 1.19 inches which is more than
250% of normal.
The strong southwesterly flow aloft and associated divergence is
producing a large area of ascent and light to moderate rainfall
across the western Carolinas and into GA. Over the last few hours
widely scattered convective showers with locally heavier rain but no
lightning have developed in the Coastal Plain. The large area of
rain across the western Carolinas will shift east overnight
spreading across most of the Piedmont. As the mid levels become
slightly more unstable the steady rain in the Piedmont will be mixed
with a few heavier showers. The more convective showers across the
Coastal Plain are apt to continue overnight and gradually shift
east. Would not be surprised to see a few lightning flashes
overnight especially in the Coastal Plain and we`ve include thunder
in the forecast in these locations. In addition, the widespread rain
will likely result in a difficult commute in the morning, especially
in the Triad and western Piedmont. Temperatures will remain steady
or even rise a degree overnight. -Blaes
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 241 PM Tuesday...
A strong, deep trough will lift through the eastern seaboard
Wednesday, combining with anomalous low-level moisture transport to
promote a good swath of moderate to heavy rain.
Ahead of a sfc cold front, moderate to heavy rain will likely be
ongoing across the western to central portions of our area early
Wednesday morning. As the trough pivots eastward (and takes on a
more negative tilt), strong mid-level height falls will spread east
across central NC. This will promote continued moderate to heavy
rain as the main band pivots east across the Piedmont/Coastal Plain.
Rain will move east of our area by early Wednesday evening.
Severe weather concerns: The latest HREF guidance continues to
depict the strongest 4-hrly updrafts along and off the Carolina
coastline Wednesday afternoon. Updraft helicity probabilities peak
over there too, with perhaps a few streaks through Sampson county
tomorrow afternoon. Similarly, the HRRR Neural Network guidance
also shows highest severe probabilities just east of us across
Morehead city`s CWA, and less so over our Coastal Plain. As such,
there seems to be pretty consistent run-to-run consensus that the
highest severe weather threat should be mostly east of our area
Wednesday (SPC just added a slight risk in this vicinity;
maintaining primarily a marginal for those east of US-1 in our CWA).
While the SPC has introduced a 2% contour for tornado probabilities
in our Coastal Plain (likely a result of HREF updraft helicity
swaths showing a slight inland shift), most guidance simulates
primarily straight and elongated hodographs over our area. As such,
while an isolated tornado can`t be ruled out, if any instability is
realized, the primary concern would more-so favor a stronger storm
capable of damaging wind gusts especially for those east of I-95
(~in the 16Z to 22Z timeframe).
Hydro concerns: QPF continues to highlight highest totals in the
Triad (~2 inches), with a bit less with further eastward extent (1
to 1.75 inches along and east of US-1). However, latest HREF 1 to 3
hrly FFG exceedance probabilities are virtually 0 % over our area
through the duration of the event. Thus, don`t think we`ll see
anywhere near widespread flash flooding tomorrow. Although, given
some south to north training potential, and the potential for some
higher rain rates (given strong forcing aloft + PWAT ~270% of
normal), can`t fully rule out isolated flash flooding in urban
areas.
Pre-frontal wind gusts: Latest guidance suggests that any pre-
frontal mixing of stronger swly gusts to the sfc may be confined to
the far eastern Coastal Plain/coastal areas. Still, can`t rule out
some 20 to 30 mph gusts for those east of I-95 Wednesday afternoon
as moderate to heavier rain pulls the incredibly strong flow aloft
down to the sfc.
Post-frontal wind gusts: Immediately behind the front, strong 25 to
35 mph gusts will be possible for a few hours. Gusts will subside by
Wednesday night and into the overnight period.
Lastly, a few rogue ensemble members show enough lingering post-
frontal moisture to allow some snow activity in our Triad areas. I`m
fairly confident that this will not occur, and any snow would be
confined to the upslope mountain areas.
&&.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 400 PM TUESDAY...
Behind Wednesday`s cold frontal and upper trough passage, strong
height rises and subsidence will result in sunny skies. Meanwhile,
Arctic high pressure will build down from the Northern Plains into
the Mid-Atlantic on Thursday and Thursday night. While NW winds will
subside compared to Wednesday, continued CAA will bring much cooler
temperatures, with Thursday`s highs only in the upper-40s to lower-
50s. Friday morning`s temperatures look quite chilly with decent
radiational cooling, so expect lows mostly in the mid-to-upper-20s
with lower-20s possible in outlying areas. The Arctic high will
continue to strengthen to around 1040 mb and build down from the
Northeast US on Friday, bringing highs only in the mid-40s to 50.
The air mass will begin to modify on Friday night as the high starts
to retreat northward, but lows will still be slightly below normal
(mid-20s to mid-30s).
Mid and high clouds will increase on Saturday as a mid/upper low
moves from the Central Plains into the Upper Midwest and the flow
aloft turns more southwesterly. While the best forcing will stay
well to our north, confidence is increasing in a period of light
precipitation sometime from Saturday night to Sunday night. Keep
POPs capped at chance at this time based on the latest ensemble
guidance and uncertainties in timing, especially given it`s Days 5-
6. Forecast highs Saturday are upper-40s to upper-50s, increasing to
lower-50s to lower-60s on Sunday, while lows this weekend should be
upper-30s to mid-40s.
Yet another wave looks to move across the Central US on Monday, but
how it will affect our area is uncertain at this time as the ECMWF
keeps it wrapped up and farther west over the Great Lakes while the
GFS is more progressive and brings a trough/cold front into our area
on Monday night and Tuesday. For now just have slight chance POPs
through the period, as guidance is mostly dry. The warming trend
should continue early next week with above-normal temperatures.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 625 PM Tuesday...
TAF period: There will be widely varying conditions through the
course of the next 24 hours. There will be a tight gradient between
VFR and IFR ceilings this evening, and this gradient is going to
fall somewhere around INT/GSO. Confidence is low for the first 6
hours of the TAF in those locations, before confidence increases in
restrictions as steady rain moves in. At other sites, a passing
shower is possible this evening, before steady rain moves into RDU
around midnight and closer to daybreak at FAY/RWI. While wind gusts
will eventually develop at all sites overnight, low-level wind shear
is also likely to be a concern. There will be little directional
shear but a good amount of speed shear. All locations are likely to
drop to IFR/LIFR as a cold front moves through tomorrow, bringing
reduced ceilings/visibilities and wind gusts. All terminals are
likely to gust to at least 25 kt, with a more potent line of gusts
expected to develop with heavier showers at RDU/RWI/FAY. VFR
conditions will return to INT/GSO by sunset Wednesday, while
restrictions will continue at RWI through the TAF period.
Outlook: VFR conditions should return to remaining terminals
Wednesday evening. Gusts as high as 30 kt will continue through the
evening. After that, dry VFR conditions are expected for several
days, with the next chance for precipitation arriving at all sites
Saturday night and Sunday.
&&
.CLIMATE...
Record Precipitation:
December 11:
KGSO: 1.46/1961
KFAY: 1.47/2008
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Blaes
NEAR TERM...Blaes
SHORT TERM...Luchetti
LONG TERM...Danco
AVIATION...Green
CLIMATE...RAH