Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/17/17
Area Forecast Discussion
National Weather Service Albany NY
939 PM EST Thu Nov 16 2017
.SYNOPSIS...
Rain showers will transition to snow showers tonight, with some
accumulating snowfall over the higher terrain mainly north of
the Capital District. Cold and brisk conditions in store for
Friday, as high pressure builds eastward from the Great Lakes. A
stronger storm system will approach on Saturday, bringing the
next chance for widespread precipitation.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Gusty winds this evening across the CWA. 00Z ALY sounding
showed steep low level lapse rates - sfc to 850mb of 8C/km. VAD
depicting winds to 45 knots up to about 850mb. RAP soundings
show good mixing to continue through the night. Bumped up wind
gusts particularly down the Mohawk Valley.
Rain showers have transitioned to snow showers across the
Adirondacks. Temperatures are still too warm most other locales,
so just rain showers now. HRRR shows a decided diminishing trend
in precipitation through the night. This is accounted for in
current forecast.
The winds and mostly cloudy conditions should prevent
temperatures from falling as much as they could but the
deepening cold advection will help temperatures fall to around
30 to the mid 30s but mid to upper 20s in the southern
Adirondacks.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Upper energy exits and the cold advection continues with breezy
west to northwest winds. Sources of guidance suggest quite a bit
of sunshine Friday but with wind off the warm lakes, there may
be intervals of clouds and sun until afternoon when the winds
diminish more rapidly. Still some sun and wind should help
temperatures reach solidly in the 40s but 30s in the southern
Adirondacks.
The next system approaches through Friday night with warm
advection rapidly increasing. Some question as to the timing of
the onset of thicker cloud cover and increasing low level winds.
Current sources of guidance suggest a period of clear and calm
conditions Friday evening, allowing temperatures to fall to the
upper teens and lower 20s before thicker clouds and increasing
south winds help temperatures to rise into the upper 20s by
daybreak Saturday.
The timing of the onset of precipitation looks to be after
daybreak to mid morning Saturday in western areas, when
temperatures rise above freezing. Boundary layer temperatures
are expected to be above freezing at that time, so other than a
possible brief light mix of rain, snow and/or sleet for an hour
or two, precipitation over our region Saturday and Saturday
night should be rain. No accumulation is expected.
Southwest boundary layer flow becomes quite strong Saturday
along with strengthening isentropic lift and upper dynamics,
supporting a widespread rain through Saturday night. Highs
Saturday in the mid 40s to around 50. Temperatures will fall
with the frontal passage mainly just after daybreak Sunday into
the mid 30s to lower 40s.
Deep cold advection spread across the region Sunday with very
strong west to northwest boundary layer flow, much of which is
likely to mix to the surface. The cold air over the Great Lakes
should aid in the development of some lake effect snow shower
activity that should extend east into our region, with the best
coverage in the southern Adirondacks but scattered activity that
could extend through the region into western New England. Highs
Sunday in the 40s to near 50 but 30s in the southern
Adirondacks and temperatures falling in the afternoon.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Sunday night-Monday looks to remain active in the wake of the strong
weekend storm system. Lingering Lake Effect/Enhanced snow bands look
to potentially impact portions of the western Mohawk Valley and
western Adirondacks through Monday, with additional enhancement
possible across west facing higher terrain of the southern Greens
and northern Berkshires. Some filaments of snowbands could
occasionally extend into valley areas. It should remain windy, with
some gusts possibly approaching or exceeding 40 mph within portions
of the Mohawk Valley/Capital Region and Berkshires.
It should remain cold, with Sunday night lows ranging from the teens
across the Adirondacks, to the 20s elsewhere. Highs Monday ranging
from the upper 20s across the Adirondacks, to the mid 30s/lower 40s
in valley areas.
For Tuesday-Wednesday, most 12Z/16 global deterministic models and
ensembles suggest a fast moving northern stream system passes north
of the Great Lakes and across SE Canada. A brief surge of milder air
should allow temps to reach into the 40s/lower 50s for much of the
region Tuesday afternoon, except cooler across the Adirondacks. Some
rain/snow showers will be possible within the warm advective regime,
possibly combining with some Lake Enhanced moisture, across the
western Adirondacks Tuesday afternoon. Then, slightly greater
coverage of rain/snow showers for Tuesday night into Wednesday
morning, as a cold front associated with the system moves through.
Temps should fall into the 20s and 30s by daybreak Wed, with highs
Wed mainly in the 30s to lower 40s.
High pressure looks to build into the region Wednesday night and
Thursday, assuming southern stream moisture/energy does not track
farther north. It should be rather chilly, with lows Wed night in
the teens and 20s, with Thursday highs mainly in the 20s and
30s.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Expect VFR conditions at most terminals through the period.
Exception will be KPSF where westerly upslope flow will induce
some MVFR clouds tonight.
Expect gusty winds to persist through the period at all
terminals. Winds should be stronger at KALB and KPSF.
Outlook...
Friday Night: No Operational Impact. NO SIG WX.
Saturday: High Operational Impact. Likely RA.
Saturday Night: High Operational Impact. Breezy Definite RA.
Sunday: Moderate Operational Impact. Windy With Gusts To 39.0 Chance of SHRA.
Sunday Night: Low Operational Impact. Breezy Isolated SHSN.
Monday: Low Operational Impact. Breezy Isolated SHSN.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: Low Operational Impact. Breezy NO SIG WX.
&&
.FIRE WEATHER...
Rain showers will transition to snow showers tonight, with some
accumulating snowfall over the higher terrain mainly north of
the Capital District. Cold and brisk conditions in store for
Friday, as high pressure builds eastward from the Great Lakes. A
stronger storm system will approach on Saturday, bringing the
next chance for widespread precipitation.
Gusty west to west winds expected tonight and Friday, up to 35
mph in some spots. Winds diminish to light and shift to south
Friday night, increasing to around 15 mph Saturday. RH values
remaining above 35 percent through Saturday with widespread rain
expected Saturday.
&&
.HYDROLOGY...
No hydrologic problems are expected on the main stem rivers
through the next week.
High pressure will briefly build in on Friday before a strong
low pressure system approaches from the Great Lakes Region on
Saturday. Widespread rain may begin as a mix with snow in the
western Mohawk Valley and southern Adirondacks but then change
to to all rain that will continue through Saturday night. A cold
front will sweep through Sunday morning with additional
precipitation. At this time, total QPF from this system looks to
range from a half inch to near an inch.
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...NAS
NEAR TERM...OKeefe/NAS
SHORT TERM...NAS
LONG TERM...KL
AVIATION...KL/OKeefe
FIRE WEATHER...NAS
HYDROLOGY...NAS
Area Forecast Discussion
National Weather Service Bismarck ND
942 PM CST Thu Nov 16 2017
.UPDATE...
Issued at 940 PM CST Thu Nov 16 2017
Band of 700-650MB frontogenetical forced precipitation
materialized as the RAP/HRRR portrayed from west central ND into
my north central. Area web cams showed precipitation started to
reach the surface around Dunn County though air temperatures are
on the rise with the precip with no travel hazards reported as of
yet west. However, road sfc temperatures over my northeastern CWA
at Rugby and Dunseith in the 20s so expect even light rain to
freeze on contact with the ground so we opted to throw out a
winter weather advisory for freezing rain across my northeast and
east central through 3 am CST.
UPDATE
Issued at 700 PM CST Thu Nov 16 2017
Main forecast challenge this evening will continue to be the
threat for light freezing rain and/or sleet and associated impacts
to travel.
Combination of low, mid, upper level forcing generating clouds and
some light radar returns at the moment. Most of the radar returns
across western ND are elevated with cloud bases at or above 10K FT
AGL. However, across far southwestern ND cloud bases have been
dropping the past hour or two along with a few obs reporting light
rain where 700-650MB frontogenetical forcing is developing, north
of sfc low pressure across northwest SD and ahead of a cold front
dropping south from Canada. Models portray this frontogensis
increasing this evening east-northeast across west/central ND
along with both the HRRR and RAP showing a decent band of light
precipitation. Warm air aloft ahead of the cold front will allow a
window of freezing rain/sleet coupled with road surface
temperatures already dropping to freezing and below.
Have mentioned this in the HWO and considering a special weather
statement for now rather than a winter weather advisory for
freezing rain as expect any precipitation to quickly move to the
northeast with minimal amounts of QPF.
&&
.SHORT TERM...(This evening through Friday)
Issued at 217 PM CST Thu Nov 16 2017
Challenges for the short term include clouds and temperatures
associated with wrm/cold frontal passages well as a light mix of
rain/snow and sleet/freezing rain. All this would be of
significance except the precipitation amounts are very light. Its
hard to find much QPF in the models. So kept the POPs low tonight
and let the process generate the precipitation type. Mostly
rain/snow chances southwest and central with some snow/sleet and
freezing rain across the northern James River valley late this
evening and after midnight. With trace amounts of QPF do not think
this will rise to a significant event.
Daytime Friday will start with the cold front moving through the
region and high pressure building into the north. The frontal
baroclinic zone will remain across far southern North Dakota and
this is where a chance of rain and snow will linger through the
day.
.LONG TERM...(Friday night through Thursday)
Issued at 217 PM CST Thu Nov 16 2017
After Friday, a dry period is forecast through Tuesday as the h500
flow remains westerly and dry. A short wage trough will move
across southern Canada Early next week bringing a cold front
through and cooling temperatures for Tuesday. Some light rain or
snow shows up on Wednesday as return flow brings warm advection
into teh region. So far Thanksgiving looks mainly dry with near to
above average temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 700 PM CST Thu Nov 16 2017
VFR conditions at all terminals through the 00Z period. There will
be a window for light freezing rain/sleet this evening for mainly
KDIK and KMOT. For now held off on mentioning in the TAFs with
uncertainty high.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 3 AM CST Friday for NDZ004-005-012-
013-022-023-025.
&&
$$
UPDATE...NH
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...NH
Area Forecast Discussion
National Weather Service Caribou ME
1010 PM EST Thu Nov 16 2017
.SYNOPSIS...
Low pressure will track northeast through the Gulf of Maine this
evening, then move into the Canadian Maritimes overnight and
into Friday. High pressure will build in for Saturday, following
by another low pressure system for Sunday.
&&
.NEAR TERM /THROUGH FRIDAY/...
940 PM Update: No sig chgs from prev update, with latest radar
imagery showing a developing deformation band ovr Ern and Cntrl
ptns of the FA. Despite sfc winds now coming and to the N across
the Rgn, max wrmg is currently occurring in the 1000 to 3000 ft
abv ground lvl across Nrn areas, as evident with mixing reports
from the KFVE ASOS. Dynamic cooling from alf will be soon
arriving from the NW with the next 2 to 3 hrs as the upper low
apchs ovrhd. One concern is how sharp the precip cut-off is ovr
Wrn ptns of the Rgn, with mid lvl dry air evident encircling W
in close proximity of the upper low. This could result in
sharper total snfl cut-off ovr NW Aroostook county then we
currently show.
Otherwise, fcst hrly temps/dwpts were adjusted from latest sfc
obs to msly unchgd fcst ovrngt lows posted near 7 am Fri.
Orgnl Disc: A vigorous shortwave in southern New England is
moving northeastward in a broader upper trough centered over
Quebec. Cyclogenesis occurred this morning in response to this
shortwave, a powerful upper jet and a strong baroclinic zone.
The deepening low pressure system is currently just south of
Cape Cod and will track towards Washington County later tonight
and onward into New Brunswick Friday morning. The low will bring
rain to most of the area with amounts over a half inch over
large portions of the forecast area and some areas could get an
inch. Snow will be a factor for locations in northwest Aroostook
County this evening before mixing with rain late this evening.
However, as the cold upper low moves over the area after
midnight, snow will return with a trowal-like structure. As a
result, have issued a Winter Weather Advisory for northwest
Aroostook County and will be carefully watching northeast
Aroostook where rain will change to snow after midnight. At this
point, am expecting just 1 to 2 inches with temperatures near
33-34F and have not extended the advisory eastward. However,
recent HRRR runs are trending a bit colder with a faster
changeover and more intensity along the northeast border of the
state. Snow will wrap up early Friday morning in the northeast
portion of the forecast area. Northwest winds will then become
the primary item of interest as the low continues to deepen in
the Canadian Maritimes. Gusts to 40 mph will be possible with
some power outages possible. Added patchy blowing snow to areas
that are forecast to receive snow overnight into Friday morning.
High temperatures will occur Friday morning and temperatures
will be falling by mid afternoon. Apparent temperatures will
fall into the teens Friday afternoon.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
Weak cold advection can be expected for Friday night on the
backside of low pressure that will be moving through the
Canadian maritime provinces. With a bit of a gradient remaining
across the area and at least some lingering stratocumulus
clouds, mainly across the north, it doesn`t look like an ideal
radiational cooling night. Nevertheless, lows are still expected
to be below normal for this time of year. High pressure briefly
builds in from the south early Saturday before increasing high
and mid clouds will be advancing across by afternoon, ahead of
low pressure tracking east from the lower great lakes region.
Expect some light overunning precipitation to develop across the
western sections by later Saturday afternoon but most of the
region should remain dry through the daylight hours Saturday.
Expect light overrunning precipitation to overspread the entire
area overnight Saturday as the low level warm advection
strengthens in advance of intensifying low pressure approaching
from the west. Although we could see a brief period of snow or
mix across the north and west at the onset, the southerly flow
in advance of intensifying low to our west will assure a change
to all rain across all areas by daybreak Sunday as temperatures
slowly rise overnight. Sunday will be a wet and unseasonably
mild autumn day as low pressure tracks just to our west and into
Quebec. Expect the steadiest rain early Sunday to then become
more showery in nature as the low tracks off to our north
during the afternoon. One concern on Sunday is the potential
for stronger southwest winds along the down east coast where
gust to 40 to 45 mph cant be ruled out as low pressure
intensifies to our west. It will be unseasonably mild on Sunday
with high temperatures climbing into the low to mid 40s north
and upper 40s to lower 50s downeast.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Strong cold advection commences Sunday evening as low pressure
intensifies to our north. A few evening snow showers cant be
ruled out Sunday evening but the bigger concern could be
freezing of any standing water from Sunday`s rainfall, as
temperatures start to tumble below freezing by evening. The work
week starts on the blustery and cold side on gusty northwest
winds with partly to mostly cloudy skies north, and partly
cloudy down east. Highs on Monday across the north not likely to
get out of the low to mid 20s, and only to near the freezing
mark down east. Monday night will see increasing high clouds in
advance of low pressure tracking well off to our northwest
across central Canada. Tuesday will see a significant rebound in
temperature as strong southwest flow between the low to our
northwest and high pressure east of the mid atlantic sends the
temperature into the mid to upper 30s north and low to mid 40s
downeast. Tuesday night will see a cold front crossing the
region with the potential for a few rain or snow showers later
Tuesday night. Early indications for the big travel day next
Wednesday and Turkey day looks quiet with no significant
precipitation expected to hamper travel, although it does turn
cooler on Wednesday and for the Thanksgiving day holiday.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: FVE will be LIFR to IFR into Friday morning due to
low cigs and snow. Other sites will trend to IFR due to cigs and
drizzle initially...and then to LIFR at times in snow after
midnight for terminals north of HUL. BGR and BHB will improve to
VFR in the predawn hours and stay VFR through the day. When snow
ends Friday morning north of HUL, conditions will improve to
MVFR cigs...and then VFR in the afternoon. Strong gusty
northwest winds will affect all terminals on Friday. Gusts may
reach 35 to 40 mph at times.
SHORT TERM: VFR Friday night through Saturday. Conditions then
lower to MVFR and IFR Saturday night and Sunday in lowering
clouds and developing precipitation. Sunday night through
Tuesday we are expecting VFR conditions to rule. The main
concern Monday will be the gusty northwest winds that are
expected.
&&
.MARINE...
NEAR TERM: Winds and seas will increase later tonight...and
reach gale strength on Friday. Left the headline in place
without change with the start time now at 9am Friday.
SHORT TERM: Gale Warnings are up into Friday evening but winds
should be diminishing later Friday night through Saturday
afternoon. By Sunday we could once again see strong SCA, if not
Gale Force conditions in the southwest flow ahead of advancing
low pressure to our west.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory until 11 AM EST Friday for MEZ001.
MARINE...Gale Warning from 9 AM to 10 PM EST Friday for ANZ050>052.
&&
$$
Near Term...VJN
Short Term...Duda
Long Term...Duda
Aviation...VJN/Duda
Marine...VJN/Duda
Area Forecast Discussion
National Weather Service State College PA
1032 PM EST Thu Nov 16 2017
.SYNOPSIS...
High pressure will build across the state through Friday. A
frontal system will move into the area Saturday with much colder
and blustery conditions following it for the end of the weekend
into early next week.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Isolated showers or rain and snow continue to decrease in
intensity and coverage. HRRR dissipates these completely by 06z
but it appears they may linger just a bit longer. Still gusty
west- northwest blowing 25 to 35 mph in spots...slowly
decreasing in the pre dawn hours.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
Friday will be fair and uneventful as we get a break between
frontal systems. Highs will be a tick or two cooler than today
with a diminishing wind as high pressure moves over the area.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
The next impactful weather system will be a storm system that
will move through the eastern Great Lakes Saturday. A warm
front-cold front combination will bring a period of rain to the
area that will be moving in from the west by sunrise Saturday,
progressively spreading eastward across the region during the
day. QPF into Sat night will be around an inch over the NW
mountains tapering to 0.25-0.50 over the SE.
The associated cold front is made to pass through the state
Saturday evening and overnight, ushering in a shot of cold air
and setting the stage for an early season bout with lake effect
snow showers for Sunday and Monday. The usual snowbelt areas of
NW Warren county into northern McKean County will be the most
likely so see several inches of snow, with lesser accums even
down into the Laurels.
High pressure moving to our south will influence the weather to
start Thanksgiving week, bringing a couple of cool-dry days.
Temperatures will begin to modify Tuesday with a SW flow
expected to develop. Though jet stream will remain north of the
region, a quick moving trough will brush the region on Wed
followed by a weak shortwave Wed night, which will bring chance
for light snow showers back into the NW along with a return of
slightly cooler air. GFS hangs on to this trough into
Thanksgiving weekend, while the ECMWF brings a flatter 500mb
flow pattern. So forecast confidence remains on the low side in
the 7-10 day range.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
MVFR/IFR conditions will persist at KBFD/KJST through tonight
with periods of snow showers. Soundings suggest pockets of
light fzdz are possible later tonight but will not mention in
TAFs. KAOO/KUNV may see some MVFR cigs at times but VFR will be
the dominate flight category. Downsloping winds will maintain
VFR flying across the eastern 1/2 of the airspace over most of
ZNY sector. Surface winds from 280-310 degrees gusting 20-25KT
early will subside into Friday morning. Expect low clouds to
gradually break on Friday with return to widespread VFR by the
afternoon.
Outlook...
Sat...Widespread showers. LLWS possible. Transition to snow
showers behind strong cold front late Saturday night with
MVFR/IFR likely western 1/3.
Sun...MVFR/IFR in snow showers NW. MVFR to low VFR cigs and
ocnl rain/snow showers central and east. Gusty winds 25-30kts
from 280-310 degrees.
Mon...MVFR cigs/sct -shsn psbl early NW 1/4; otherwise VFR.
Tue...Breezy. Mainly VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Gartner
NEAR TERM...DeVoir/Gartner
SHORT TERM...La Corte/Gartner
LONG TERM...La Corte/RXR
AVIATION...Steinbugl
Area Forecast Discussion
National Weather Service Duluth MN
654 PM CST Thu Nov 16 2017
.SHORT TERM...(This evening through Friday)
Issued at 200 PM CST Thu Nov 16 2017
After a mostly dry day today across much of the Northland, we once
again will be dealing with an incoming system that will bring a
wintry mix of precipitation, which should make for hazardous road
conditions, especially for the Friday morning commute.
A one-two punch of a warm front, followed by a push of cold air
advection on the backside of a sfc low that is progged to translate
across southern Saskatchewan and Manitoba Canada, will be the
culprits for this precipitation. Model soundings indicate that the
atmospheric profile will saturate this evening and overnight due to
seeder-feeder processes. The push of warmer air behind the warm
front will complicate the forecast as far as p-types are concerned.
RAP soundings indicate a warm layer of roughly 1 to 2 degrees
Celsius at around the 800 mb level, with perhaps even warmer
maximum temperatures possible. This would support a range of
p-types, including snow, rain/snow mix, drizzle, freezing
drizzle, and sleet. Overnight, temperatures should remain cold
enough through the atmospheric profile to support mainly snow,
with some isolated drizzle/freezing drizzle. The p-types become
more eclectic just in time for the Friday morning commute, with
drizzle, freezing drizzle, sleet, and snow all possible during
that time. Confidence in the exact timing and placement of each p-
type is rather low with this setup. The good news is that the
freezing precipitation will diminish by Friday afternoon as
temperatures look to warm up to the lower to middle 30s across the
area, with most locations seeing temperatures above freezing.
However, freezing precipitation will return Friday night and
Saturday morning. New snow should mainly fall over our
northeastern portions of the forecast area, especially over the
Minnesota Arrowhead, where up to 1" to 2" of new snow is possible
over Lake and Cook counties Friday. Ice accretions appear to be
very light, if any, with the best chances of icing over Price,
Ashland, and Iron counties in northwest Wisconsin. Due to the lack
of heavier accretions of ice, we will hold off on any headline
issuances at this time. Also, due to a tight sfc pressure gradient
moving in from the west, southerly winds will be gusty across the
area overnight, with gusts between 20 to 25 knots possible.
.LONG TERM...(Friday night through Thursday)
Issued at 200 PM CST Thu Nov 16 2017
The area of low pressure will move through northwest Wisconsin
Friday night, being pushed along by an upper level trof. The wintry
mix of ptypes persists, but expecting more of a drizzle/freezing
drizzle ptype, along with light snow. Dry over northeast Minnesota.
The precipitation diminishes in northwest Wisconsin as forcing
departs. Have some small pops Saturday morning as the wind aligns
for an opportunity for some light lake effect snow showers. However,
model differences in the amount of dry air advecting over Lake
Superior may offset the favorable wind. Ridging moves over the rest
of the forecast area Saturday. Confidence is low on lake effect snow
through Sunday morning with the dry air appearing to prevail. Warm
and dry air surges into the area Sunday night and Monday ahead of
the next system. Monday night finds this next system moving along
the international border region through Tuesday. A cold front is
progged to move through the region and bring the next round of snow
showers. As ridging returns for Tuesday night and Wednesday, lake
effect processes begin again with a northwest flow. Have adjusted
pops accordingly.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 637 PM CST Thu Nov 16 2017
For the most part MVFR, but believe IFR in -shsn band that is
crossing the area. Band may produce a quarter of an inch of
snowfall at KDLH. Elsewhere, most TAF sites miss the band of snow.
Afterward 05Z, a general transition towards IFR as more -shsn
moves in eventually mixing with rain. Expect poor flight
conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 27 35 23 27 / 30 60 10 0
INL 24 35 18 22 / 50 20 0 10
BRD 30 38 23 28 / 20 30 10 0
HYR 30 36 27 31 / 20 80 40 10
ASX 29 38 29 31 / 30 80 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 3 PM CST Friday for LSZ140>142.
&&
$$
SHORT TERM...JTS
LONG TERM...GSF
AVIATION...Wolfe
Area Forecast Discussion
National Weather Service Green Bay WI
947 PM CST Thu Nov 16 2017
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Friday
Issued at 222 PM CST Thu Nov 16 2017
The latest RAP analysis and satellite/radar imagery show high
pressure moving across Wisconsin early this afternoon. Low clouds
remain stubborn so far today, though partial clearing has taken
place south of route 29. Think clearing will continue to slowly
lift north for the rest of the afternoon. Meanwhile, the jet
stream is already bringing in broken cirrus into western Wisconsin
ahead of the next system. Precip chances and potential impacts
from this system are the main forecast concerns.
Tonight...The high pressure system will exit to the east over the
central Great Lakes. As this occurs, winds will shift to the
southeast, which should continue to cause the low stratus to lift
north over northern WI through the early evening hours. However,
clouds over Lake Michigan may also return west into eastern
Wisconsin. Combined with a thick blanket of cirrus arriving this
evening, will show increasing clouds across areas where skies
cleared for a time. Progged soundings indicate that ample mid-
level dry air will likely hold off precip for most locations
overnight. Some models create a band of precip over northern WI
after midnight despite this dry air, and suppose its possible
that a few snow flakes could survive the trip to reach the ground.
So left a small chance in the forecast, with a tenth or two of
accum possible. As a result, think the threat of impacts to the
roads is rather minimal.
Friday...A stronger push of deeper moisture will occur from west
to east during the morning hours. The mid-level dry wedge will
become significantly eroded as the moisture arrives, with wet
bulb temps aloft rapidly rising into the 3-5C range. This should
lead to a transition into more of a rain/drizzle scenario by mid
to late morning. There may be a brief few hour window when surface
temps are at or just below freezing with liquid precip falling,
which could result in hazardous roadways. Because of such a narrow
window and uncertainty about timing and precip type, will issue
an SPS to draw more attention to this potential hazard. As precip
moves across central and into eastern WI by late morning through
the afternoon, temps should warm into the mid 30s to low 40s.
.LONG TERM...Friday Night Through Thursday
Issued at 222 PM CST Thu Nov 16 2017
The main focus continues to be the beginning of the extended
period for potential wintry mix and high winds through Saturday.
Colder air will move into the region after midnight Friday night.
Initially, primarily drizzle and rain are expected to continue
initially overnight as drier air returns aloft and cuts off the
supply of ice crystal growth. Active weather will then transition
over to snow in the north as the cold air continues to push into
the region. Mixed precipitation is likely across central
Wisconsin in the morning while the Fox Valley keeps mostly rain
chances. Bufkit soundings suggest a brief chance to see mixed
precipitation reach the Fox Valley in the afternoon. There will be
a small chance to see some light snow across the area into the
evening, but currently favor dry air moving in more quickly in the
end of this system, thus kept pops minimal in the evening for
Saturday. The last of the snow showers will be in the far north as
some lake enhancement continues in far northern Wisconsin. Models
have backed off some on the wind speeds over land Saturday, with
gusts closer to around 25 to 30 knots likely Saturday afternoon
and evening.
Drier conditions follow all the active weather on Sunday into
Monday. Models currently suggest the next chance of precipitation
arriving Tuesday into Wednesday as we return to a more meridional
flow, although timing confidence is low at this time.
Temperatures during this time will fluctuate with the passing
systems, with highs hovering in the 30s Saturday, dropping
towards the 20s Sunday, 40s on Monday, and then returning to the
20s and lower 30s through the rest of next week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 946 PM CST Thu Nov 16 2017
MVFR clouds have retreated to far eastern Wisconsin and southern
Wisconsin late this evening. Drier air, as per MSP and GRB
soundings, have worked into the state with mainly mid level
clouds over the area. Nearest precipitation was a band of snow
showers near DLH where some better saturation was occurring.
Anticipate MVFR cigs will increase in coverage later tonight into
Friday, however the trend may be slower along with the coverage
of precipitation. Pcpn type may be more snow initially due to the
colder dry air in place before turning to a mix Friday morning.
Boundary layer expected to warm enough to become mainly rain
Friday afternoon.
&&
.MARINE...
Issued at 222 PM CST Thu Nov 16 2017
Another low pressure system could bring additional
chances for gale force winds, first from the south on Friday ahead
of the system, then from the northwest behind the system on
Saturday and Saturday evening. Confidence is high enough to
upgrade to a gale warning for Lake Michigan, but not for Green Bay.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Uhlmann
AVIATION.......TDH
MARINE.........MPC
Area Forecast Discussion
National Weather Service Lincoln IL
852 PM CST Thu Nov 16 2017
.UPDATE...
Issued at 852 PM CST Thu Nov 16 2017
Updates this evening are mainly for cloud cover as overcast skies
that were prevalent from Galesburg to Paris northward earlier this
evening have been eroding and are now mainly from Peoria to
Champaign northward. Have updated short term forecast to account
for this, but may need further updates later this evening as well.
Otherwise, temperatures across the area are already in the low to
mid 30s, near forecast lows for tonight, and this looks good as
well as light southeast winds and cloud should keep temperatures
relatively steady.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 246 PM CST Thu Nov 16 2017
A narrow ridge of high pressure is located over IL and the
Mississippi River Valley this afternoon/evening. The high pressure
and relatively subsident air effectively trapped a layer of
moisture over the region, resulting in a more cloudy day in the
northern half of the state. Models are struggling with what to do
with the cloud remnants as not enough mixing today to make a
significant impact. HRRR had the best handle on the clouds
earlier, and latest runs keeps the stratus in for the overnight
and expands across the region. Have kept the temps up a bit from
last night...may need some minor adjusting, particularly in the
south if the clouds expand. By morning, winds come around to more
southerly behind the ridge as the next front moves into the
Midwest. Low pops in place for sct showers/mostly drizzle in the
first half of the day. Precip approaching the NW in the
afternoon/evening...and thunder increasing into tomorrow night.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 246 PM CST Thu Nov 16 2017
SPC Day 2 outlook has all of Central IL in a general thunder
threat, mainly for tomorrow evening. Rain chances better for
Friday night and into Saturday. Day 3 Outlook has a general
thunder... and a marginal risk in the far SE...south of I-70.
Concern would be surrounding early morning convection invof the
Ohio River Valley with the rapid development of the storm system
as it moves out to the east. Threat should end early as the
heavier precip moves out. However, on the other side of the
boundary, some models hinting at a weak round of precip through
the afternoon, with the temperatures NW of the IL River allowing
for the potential to see some snowflakes mixed with the rain
threat through the afternoon. Threat is brief and surface
temperatures should remain warm enough to melt most of it. Winds
become very strong behind the front as well, and Saturday
afternoon will see gusts to 30kts at times.
Temps plummet into the 20s again for Sat night and Sun night with
colder air moving into the Midwest. A period of quiet weather sets
up through the remainder of the forecast. Temps warm briefly with
southerly flow and the western ridge shifts eastward slightly for
Monday. Next system moves into the Upper Midwest/Great Lakes for
Tuesday. Pops previously in forecast have come out of the blend
for Tuesday night as the front passes dry in the past few runs of
both the GFS and the ECMWF. A mentionable difference is that the
front is not only dry, but not as cold in the ECMWF...and the GFS
is deeper with the upper trof and colder. Should the trend of the
GFS following suit with the ECMWF shift on a Day 5 forecast...the
temps in the GFS/the blends should start to modify somewhat
Tuesday night and beyond.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 551 PM CST Thu Nov 16 2017
MVFR cigs over KPIA-KDEC northeastward, with trends toward
expanding slowly southwestward. Models generally follow this trend
as well, although perhaps with a bit of a break overnight just
before stratus and drizzle expand northward out of southern IL.
Have not incorporated a break in low cloud cover into TAFs as
this scenario is too uncertain for inclusion at this point.
Overall, ceilings will trend lower and have IFR cigs by 06Z-09Z.
Winds E-SE 5-10 kts overnight, becoming SSE 10-15 kts with gusts
20-25kts after 15Z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...37
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...37