Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/15/17
Area Forecast Discussion
National Weather Service Taunton MA
1030 PM EST Sat Jan 14 2017
.SYNOPSIS...
Weak low pressure slides well S of the coast tonight. Light snow
along the South Coast will move offshore during the night. High
pressure maintains dry and seasonable conditions Sunday and
Monday. Low pressure from the Plains approaches Southern New
England with rain and mild air for Tuesday and Wednesday. The low
then redevelops to our east and moves off Wednesday night. High
pressure then builds in with dry and continued mild weather for
the end of the week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1030 PM update...
Large dew point depressions in the lower levels keeping most of
southern New England from seeing a more significant light snow.
Northern edge of the precipitation was along the immediate south
coast of MA and RI, and continuing to move east. Expecting the
radar returns to completely move out before 1 AM EST. Most
locations only reporting a dusting of accumulation, at most.
Lowest visibility in the more significant snow was about 2 miles.
Brought the forecast back in line with observed trends. Otherwise,
no major changes to the ongoing forecast.
Previous discussion...
Winds have shifted to S-SE though remain light across the region.
They may back to a SE direction along the S coast, which may allow
enough low level moisture, even with the low dewpts, to bring some
spotty light snow along the S coast of MA/RI overnight. NAM 4 KM,
RAP and GFS BUFKIT soundings are signaling light snow reaching
into KEWB, KCHH and KHYA overnight, and even for a few hours as
far N as KPVD. Think it will be tough to get it into KPVD at this
point, but still a shot along the coast. Models are suggesting
that dewpts do rise as the northern edge of the precip pushes
across, but they have had a warm bias all day today, so not
confident they will rise as quickly as the models are suggesting.
Have CHC POPs hugging along the S coast through around 06Z, then
should exit quickly as another high starts to push E out of the
Great Lakes. Strong mid and upper level jet across the region
with W-NW winds up to 135 kt at H3 on 12Z KCHH sounding and 140
kt at H25 on KALB sounding. Short range models all show this
sitting across the region overnight, then pushing E after 06Z Sun.
Skies should start to clear across N central and W Mass after 10 PM
or so, then will quickly shift eastward overnight pushing toward the
S coast toward daybreak. Winds shift to W-NW with the approaching
high. Expect temps to bottom out in the teens across most areas,
except in the 20s along the immediate coast.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Sunday...
While high pressure moves E across W NY state early Sunday, a
second high will shift E out of central Quebec. This will bring a
reinforcing shot of cold air across the region during the morning.
Noting a 30-40 kt jet shifting SE from H85 to H9 as the front
approaches. Will see good low level mixing push into the region
from H92 and below, especially across the waters by around midday
and through the afternoon.
Expect mainly clear skies across most of the region, but some
clouds will linger across the E slopes of the Berkshires. H92
temps drop to -5C to -9C by 15Z Sun then level off at -5C to -7C
during the afternoon. Should see high temps from the mid 20s to
around 30 across the higher inland terrain to the upper 30s along
the S coast.
Sunday night...
Large high pressure center will slowly cross NY state/PA, with N-NW
winds diminishing during the night. Expect mainly clear skies
through the night and, as the winds drop off, will see temps fall as
well with good radiational cooling setting up. Expect overnight lows
ranging from 5 to 15 across most areas, ranging to the upper teens
and 20s along the immediate coast and urban centers.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Big Picture...
Hudson Bay upper low retreats north, leaving a large-scale zonal
flow for much of the long term. Toward next weekend the large
scale a developing Pacific Coast trough and West Atlantic Ridge.
In the shortwave scale, Baja California upper low ejects through
the Southern Plains Monday and Great Lakes Tuesday, then New
England Wednesday. East Coast ridge then builds late week.
Contour heights are mostly forecast to be above the climatological
average. GFS does show heights briefly near normal Wednesday as the
upper trough moves past, but the ECMWF and GGEM are much warmer.
Overall this looks like a dry mild week, punctuated by a period of
rain Tuesday-Wednesday.
Model mass fields are similar through Wednesday morning, then
diverge in handling the midweek weather system. They then show a
general agreement on high pressure arriving for Friday and Saturday.
Confidence for the long term is moderate.
Details...
Monday...
High pressure settled offshore, bringing a light west to southwest
flow. The mixed layer reaches to about 950 mb, where temps support
max sfc temps of 35 to 40. Some increase in cirrus at night,
especially across CT and RI, but otherwise fair skies and light
winds. This will allow radiational cooling for a portion of the
night. Dew points 15 to 30 should allow min temps mainly 20-30.
Tuesday-Wednesday...
Models are trending slower with the onset of clouds and
precipitation. The lower airmass remains dry through midday while
mid and high clouds are on the increase.
Low level ageostropic flow turns from the north but remains 20 knots
or less. Meanwhile temps will have time to climb above freezing in
most places. If cold air does linger, it would be most likely in
some of the East Slope communities of Northwest MA. There also
remains a chance that the combination of slightly stronger drainage
flow and evening evaporative cooling could bring a period of
freezing rain in Northwest MA. This will need to be monitored.
Aside from that potential icing scenario, temperature profiles
suggest rain for our area from onset to finish.
Models are showing a coastal redevelopment of the system on
Wednesday, but disagree on the location. The GFS says Gulf of Maine
while the ECMWF says Long Island. The GGEM tries to do a little of
both. Still plenty of time for these details to sort out.
Thursday through Saturday...
The ECMWF shows a second shortwave sweeping down from Canada
Thursday while the GFS shows, at best, a very shallow version of
one. This may be good for snow showers in the hills, but moisture
profiles are sufficiently dry to maintain a dry forecast. High
pressure then builds in for Friday and Saturday. Temps in the
projected mixed layer support max sfc temps in the 40s. Dew points
are projected in the upper 20s and 30s, supporting lows in the 30s.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Sunday Night/...
Tonight...Moderate confidence. VFR conditions continue across
most of the region. An area of snow moving along the South Coast
and Islands will bring a period of MVFR cigs/vsbys, briefly
reaching IFR vsbys in the steadiest snow. Movement of the snow
would project it moves east of Cape Cod and Islands 04Z to 06Z.
SW winds shift to W for a time overnight, then NW toward morning.
Winds may gust up to 20 kt on outer Cape Cod as winds shift
after midnight.
Sun...High confidence.
VFR. NW winds gusting to 20-25 kt along the immediate E coast, Cape
Cod and the islands through early afternoon, then diminish.
Sunday night...High confidence. VFR.
KBOS TAF...High confidence in TAF.
KBDL TAF...High confidence in TAF.
Outlook /Monday through Thursday/...
Monday...High confidence. VFR.
Tuesday-Wednesday...Moderate confidence.
VFR Tuesday morning, lowering to MVFR cigs/vsbys in rain Tuesday
afternoon/evening, then IFR in rain and fog Tuesday night and
Wednesday. Conditions may improve Wednesday afternoon. Variable
winds Tuesday becoming S-SE Tuesday night, S-SW Wednesday, and
West by Wednesday afternoon.
Thursday...Moderate confidence...VFR.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Sunday Night/...
Tonight...High confidence. Light SW winds increase overnight. May
see gusts to 20 kt on the eastern open waters after midnight as
they shift from the NW. Seas 4 ft or less. Some brief visibility
restrictions across the southern waters to SE of Cape Cod in light
rain and/or snow, ending after midnight.
Sunday...Moderate to high confidence.
NW winds gusting to 25 kt on the eastern open waters and
Mass/Ipswich Bays. Seas may reach 5 ft there as well. Small craft
issued. Winds should diminish on the near shore waters around
midday, but will linger on the outer waters through the day.
Sunday night...High confidence.
Any leftover NW wind gusts to 25 kt will diminish Sunday evening
on the eastern outer waters. Seas should also subside below 5 ft.
Outlook /Monday through Thursday/...Moderate confidence.
Monday-Tuesday...Winds less than 20 knots and seas less than 5
feet.
Tuesday night-Wednesday...Southeast winds reach 25 knots on the
outer waters and possibly RI Sound, with seas building to 5-7
feet. Best chance is on the southern outer waters. Small Craft
Advisory may be needed on these waters. Visibility will be reduced
in periods of rain Tuesday night, with rain tapering off as winds
shift from the West Wednesday afternoon.
Thursday...Northwest winds will gust to 25 knots on some of the
waters. Seas of 5-7 feet will slowly diminish during the
afternoon.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 6 AM to 9 PM EST Sunday for ANZ250-
254.
Small Craft Advisory from 6 AM to 1 PM EST Sunday for ANZ251.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...WTB/Belk/EVT
SHORT TERM...EVT
LONG TERM...WTB
AVIATION...WTB/EVT
MARINE...WTB/EVT
Area Forecast Discussion
National Weather Service Columbia SC
941 PM EST Sat Jan 14 2017
.SYNOPSIS...
A stalled boundary in the southern portion of the area will
become diffuse and move back north Sunday, bringing a return to
higher temperatures. An upper ridge over the southeastern part
of the country will favor above normal temperatures through
midweek. Another front will bring showers and possible
thunderstorms late Wednesday and Thursday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A stalled frontal boundary along the southern portion of the
forecast area will become diffuse overnight. Fog will be the
main forecasting concern with some potential for dense fog.
Moisture near the surface coupled with nocturnal cooling is
already resulting in some fog development this evening
particularly in the CSRA. Dense fog potential may be limited by
high clouds and a 20 knot low level jet. Well above normal
overnight low temperatures are forecast, in the upper 40s to
near 50.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Weak high pressure will reside over the area early Sunday with
yet another backdoor front pushing into the forecast area from
the northeast later Sunday and Sunday night beneath a building
upper ridge over the southeastern states in response to the
eastward ejection of the southwestern US cutoff upper low.
Isentropic lift over the northern Midlands Sunday night into
Monday morning and will carry slight chance for light rain
during this period.
Otherwise generally fair weather is expected with continued
above normal temperatures. Sunday will be mild with highs
ranging from the mid 60s northern Midlands to the lower 70s
southern Midlands and CSRA. Monday, behind another backdoor
cold front, will be cooler with highs ranging from the upper 50s
northern Midlands to upper 60s in the CSRA.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Uncertainties continue in the extended period because of
differences in the medium-range models of the timing of a series
of upper-level disturbances moving across the area from the
west especially towards the end of the week. Medium-range
models and ensembles appear to be in reasonable agreement with
the overall large scale pattern during this period showing a
mean trough over the west and somewhat flat ridge over the east.
However, differences in the details leads to the uncertainty
with this forecast.
Deep south-southwesterly flow develops over the area Tuesday
through Tuesday night over the area ahead of a cold front
extending across the Ohio/Mississippi Valleys being driven by a
closed low over the upper midwest. Upper-level energy lifting
out of the southern Plains will push across the Southeast for
much of the remainder of the week. Chance pops look reasonable
for much of the period, with thunder possible especially later
in the week.
The only part of this forecast with above normal confidence is
the temperatures as it appears warmer than normal throughout the
period, especially regarding overnight lows which could be some
15 to 25 degrees above normal.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Moisture convergence associated with the weakening front in the
area plus nocturnal cooling should result in stratus and fog
development tonight. Most of the guidance indicated IFR
conditions developing. Followed the HRRR for the timing. Heating
and mixing along with the front becoming more diffuse supports
improvement late Sunday morning. The NAM and GFS MOS plus most
SREF members were in good agreement indicating VFR conditions by
afternoon. The pressure gradient will remain weak and expect
light wind with westerly more predominate Sunday afternoon.
EXTENDED AVIATION OUTLOOK...High low-level moisture associated
with the remnants of a front plus an onshore flow combined with
noctural cooling indicates widespread stratus and fog may occur
during the late night and early morning hours Monday and
Tuesday. Widespread restrictions may occur in showers associated
with a frontal system Wednesday and Thursday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
Area Forecast Discussion
National Weather Service Caribou ME
1012 PM EST Sat Jan 14 2017
.SYNOPSIS...
A weak frontal boundary will move across the region tonight with
some scattered snow showers across the north. High pressure will
build back in across the region through Sunday night.
&&
.NEAR TERM /THROUGH SUNDAY/...
10 PM Update...Some patchy light snow is approaching from the St.
lawrence valley and may dust western and northern areas overnight
so included low chc pops light snow in those areas tonight. Also,
clouds have kept temps up. Cold front will not move through until
very late tonight so raised overnight lows a couple degrees.
Cold for Sunday but a tad warmer than today. A band of snow
showers to affect the Crown of Maine overnight.
A weak front is forecast to slide across the region overnight into
early Sunday. Model soundings including the NAM/GFS and RAP
indicate that there is enough moisture residing from 850-700mbs.
Mid level forcing is evident from 12z ua as 700mbs analysis showed
a 45-50 kt jetstreak to swings across the region overnight. This
could be enough to kick off some snow shower activity or even a
brief period of light snow. The best llvl convergence and forcing
looks to be right along the Maine-Canadian border. Based on this
assessment, decided to increase pops to 40% in the aforementioned
area w/20-30% further s into the Caribou-Presque Isle region.
Attm, any snow accumulation will be around 0.5(1/2)inch. Clouds
will also hold up temps overnight keeping most of the region above
zero w/the exception of the far n and w as some site could go
below 0F such as low lying sites and by the rivers.
As stated above, cold on Sunday but a tad warmer w/sunshine
returning. There will be a wnw breeze of 10-15 mph especially
across the downeast and eastern areas. This will add a chill to
the air. Daytime temps will range from 10-15 across the north and
west while central and downeast areas will see low to mid 20s. One
interesting thing to note is that the GFS and NAM soundings
indicate some instability w/a slight steepening in the llvl lapse
rates over the eastern areas such as Washington County. Moisture
appears to be limited to the 850mb layer w/alot of dry air above
that layer. Therefore, kept out the mention of any snow showers,
but winds were increased a bit given the inverted v look to the
soundings and 30+ kts above 3k ft.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
High pressure will build to our south Sunday night through Monday.
Expect dry weather Sunday night with lows ranging from zero to
10 below across the north and zero to 10 above central and down
east. A weak system moving east across Quebec may bring a snow
shower or two to far northern areas on Monday, otherwise it will
continue dry. Highs on Monday will range from the low to mid 20s
across the north/central areas and upper 20s to lower 30s
downeast. High pressure will build back in for Monday night and
then move east on Tuesday. It will continue dry through Tuesday as
low pressure approaches from the west. Lows Monday night will
range from the low to mid teens north and mid teens to lower 20s
central/downeast. Highs on Tuesday will range from the mid to
upper 20s north and low to mid 30s central/downeast.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Increasing clouds can be expected Tuesday night. Precipitation
will develop, mainly after midnight, as low pressure begins to
track to our northwest. The precipitation Tuesday night will
mainly be in the form of snow but possibly a mix of snow or rain
across downeast.
Precipitation will continue to expand across the region on
Wednesday. Precipitation type on Wednesday will be dependent on
the development and track of a secondary low that is expected to
develop early Wednesday. At this point, will continue with a
blended model approach and keep precipitation type primarily snow
across the north and rain down east. Precipitation will to taper
off to snow showers Wednesday night. Expect a continued chance
for snow or rain showers on Thursday. Improving weather
conditions can be expected by the second half of the week.
Temperatures through the long term period are expected to remain
above normal.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR w/a brief period of MVFR overnight for the far
northern terminals from KPQI to KFVE. VFR for all terminals on
Sunday.
SHORT TERM: VFR conditions expected Monday through Tuesday. The
exception will be in any isld/sct snow showers across the
northern terminals KFVE/KCAR on Monday. Widespread IFR is
possible after midnight Tuesday and on Wednesday in snow north and
snow/rain downeast. Conditions should improve to MVFR/VFR
Wednesday nigh and Thursday in lingering snow/rain snow showers.
&&
.MARINE...
NEAR TERM: Decided to issue a SCA for the outer zones for later
tonight into Sunday as winds are forecast to increase to 15-20 kt
w/gusts hitting 25+ kts. The intra-coastal zone looks like it will
stay below 20 kts sustained w/a wnw flow. Seas will build slightly
but w/the offshore wind, heights will stay below 5 ft.
SHORT TERM: Winds/seas will remain below small craft advisory
levels Sunday night and then increase to small craft advisory
levels Monday. Small craft advisory conditions will then be
possible once again on Wednesday depending on the track of
secondary low pressure expected to develop.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory from 2 AM to 5 PM EST Sunday for ANZ050-
051.
&&
$$
Near Term...Hewitt/MCB
Short Term...Duda
Long Term...Duda
Aviation...Hewitt/Duda
Marine...Hewitt/Duda
Area Forecast Discussion
National Weather Service Hastings NE
954 PM CST Sat Jan 14 2017
.UPDATE...
Issued at 931 PM CST Sat Jan 14 2017
Updated the forecast this evening to bring in precipitation
earlier in our southeastern CWA. There could be some sleet at
onset, but as we warm aloft, the predominant precipitation type
tonight should be freezing rain. Also raised low temperature in
our north central Kansas counties to about where they are now,
which is around 30 degrees. They should be socked in with sky
cover and lack of any cold air advection, so a nearly steady
temperature for the bulk of the night seems the reasonable way to
go, and short-term models such as the HRRR confer with this.
As a heads up, I`m leaning toward an earlier start time for our
Ice Storm Warning, at least in the southern half of the CWA as the
HRRR and RAP indicate the potential for an earlier start time to
the freezing rain, and even a little freezing rain can cause big
problems. Looking at backing up start times to 09Z (3 am) from
roughly I-80 to the Kansas state border.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 444 PM CST Sat Jan 14 2017
Apologize for running late with this product this
afternoon...needless to say a very challenging forecast trying to
slowly-but-surely pin down the details of our upcoming winter
storm. For those watching closely, overall the snow/ice totals
were not modified much versus the previous overnight forecast
package. Will spend more time focusing on headline
decisions/general trends than hardcore meteorology in the
following few paragraphs.
Headline Decisions:
The entire CWA was either upgraded to (or continued with) an Ice
Storm Warning or Winter Storm Warning. In our 6 KS counties, the
Ice Storm Warning begins tonight, but the main impacts will not
occur until Sunday into Monday. This KS segment currently runs
through Noon Monday in coordination with neighboring KS offices,
but would not be surprised if it eventually gets extended at least
another 6 hours (something later shifts can monitor). On the
Nebraska side, warnings for the southern most few rows start at 6
AM Sunday. Finally, roughly the northern half of the CWA sees
Warnings kick in at Noon. All Nebraska counties currently run
through midnight Monday night, which corresponds to the very tail
end of precipitation potential with this system. Regarding these
headlines, a couple of very key points/reminders:
1) The split between the Ice Storm Warning (southeast) and Winter
Storm Warning (northwest) was largely based on whether ice
accumulation was expected to exceed 0.25" or fall short. In
addition, the Winter Storm Warning counties are more favored to
see perhaps at least 1-3" of snow as the system departs Monday
into Monday night (highest amounts along our far northern/western
fringes).
2) HOWEVER, all counties, even the northwest ones not in the
official Ice Storm Warning, are expected to see at least 5 to 20
hundredths of ice accumulation on average, which is plenty enough
to cause travel issues and at least limited power issues. The
bottom line: Just because you are not in an Ice Storm Warning does
not mean that you will not see any ice accumulation! It only means
that ice amounts will be a bit less, and sleet/snow amounts a bit
more. ALL counties in the CWA are subject to plenty of wintry
impacts from this system and hence the Warnings.
3) As with all headlines, don`t take "start times" too literally.
They are meant to be a general guideline for multiple-county
areas, and do not necessarily reflect exactly when precipitation
will begin everywhere within the area. Especially northern
portions of the CWA may not see much of anything until Sunday
night.
With these things outlined, will briefly cover the most important
weather details of these next few days:
The current scene as of late this afternoon:
The CWA has enjoyed a dry and modestly warmer day with highs into
the 30s all areas. Winds have been extremely light. The main mi-
upper level disturbance driving our upcoming storm is still well
southwest over the Baja area.
This evening/overnight:
Although by daybreak the main wave will still be over northern
Mexico, large-scale lift mainly in the form of mid-level warm-air
advection will get underway, as already evidenced by precipitation
increasing in coverage over central/southern KS. For our CWA,
while at least spotty light freezing rains/sleet cannot be ruled
out roughly as far north as Highway 6 in Neb overnight, the
majority of wintry precip should focus south of the state line and
thus the Ice Storm Warning starting down there first. Low temps
tonight were raised 2-3 degrees and maybe not enough, but mainly
low-mid 20s except for teens far north.
Sunday daytime:
Although it will likely not happen in one big clean "wave", but
instead multiple scattered waves of precipitation, freezing rain
and sleet will gradually overtake the CWA from south-to-north, as
forcing increases ahead of the main vort max which finally reaches
southwest TX by day`s end. The majority of precipitation/impacts
will likely focus across our southern half through the day though.
High temps only a few degrees either side of 30 so plenty cold for
ice accrual, especially on elevated/untreated surfaces.
Sunday night-Monday daytime:
This has been and continues to be the "main show". These 24 hours
are when the majority of freezing rain/sleet will occur, with some
"plain" snow finally starting to develop as Monday wears on in
western counties as colder air moves in. Anybody traveling Monday
should expect potentially treacherous conditions, especially in
those central/southeast counties that see the highest icing.
Primary models are in decent agreement that the main vort max will
reach the OK/KS border by daybreak Monday and be centered over the
northeast KS/southeast NE area by sunset. As the associated
surface low passes to our southeast, light winds will begin to
pick up modestly from the north and increase closer to 15 and
perhaps 20 MPH. Still though, not overly strong by our standards.
For now, we are still expecting some modest warming to slightly
above freezing in southern/southeast zones Monday afternoon, which
hopefully occurs and allows a switchover to plain rain. If this
does not occur, the southern Ice Storm Warning for KS zones may
need extended beyond noon.
Monday evening/night:
Fortunately, by sunset enough cold air will be sweeping in aloft
from the west to result in a fairly rapid decrease in freezing
rain/sleet potential and more of a transition to snow. We are not
expecting major snow amounts, but instead more of a quick-moving
but perhaps briefly intense band that lifts across from west-to-
east from the late afternoon through evening hours before largely
departing by midnight. At least a few inches are expected in our
far western/northern counties with perhaps only a few flurries/a
light dusting in southern/eastern zones. Sustained winds may try
to increase closer to 20 MPH with slightly higher gusts during the
night (from the northwest), but unless the associated surface low
happens to strengthen much we are not looking at "truly strong"
winds the likes of which we often can expect behind these system,
and this is good thing for hopefully mitigating infrastructure
damage from icing.
.LONG TERM...(Tuesday through Saturday)
Issued at 444 PM CST Sat Jan 14 2017
For hopefully obvious reasons with all of the weather in the short
term...spent very minimal time digging deep into the latter 5 days
of the forecast.
Briefly summarizing:
Little change made from previous forecast. The best news for most
folks is that we are looking at a mainly dry forecast along with a
fairly decent warm-up to at least slightly above average levels.
Temperature summary:
Although am admittedly a little skeptical about how quickly we
warm up given the expected accumulations of ice/sleet/snow over
the next few days, there is plenty of evidence per both the GFS
and ECMWF that westerly-to-southerly low level flow will give
things a nice boost. High temps Tuesday are aimed into the mid-30s
to low-40s range, with highs then aimed well into the 40s and even
a few 50s Wednesday-Friday before easing back a few degrees on
Saturday but still widespread 40s. Overnight lows generally 20s to
around 30s.
Precipitation summary:
There are some very low chances for rain and/or snow in the
Friday-Saturday time frame as both the ECMWF/GFS swing the next
primary mid level disturbance in from the southwest. Although the
details are extremely murky at this time, for now these look like
pretty minor/low-impact precip chances, with the temperature
profile likely less-conducive to mixed precip types than with the
impending short-term storm.
Possible hazards:
None foreseen from precipitation at this time. In other
departments, although ice jam issues are extremely hard to
foresee, the general pattern of widespread precipitation
potentially in excess of one-half inch in some areas (quite a bit
for January), followed by a decent warm-up could possibly give us
a shot at some ice jam issues in our typically-favored spots along
the Platte/Loup Rivers as the week goes.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday evening)
Issued at 545 PM CST Sat Jan 14 2017
Main issue will be the onset of frozen precipitation, which could
be a mix of sleet and freezing rain, with freezing rain being the
primary focus as an Ice Storm Warning is in effect for KGRI
beginning 18Z Sunday and Winter Storm Warning in effect at 18Z for
KEAR, where there is still ice expected, but should stay under 1/4
inch ice accumulation. Ceiling will gradually lower through Sunday
afternoon.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Ice Storm Warning from 6 AM Sunday to midnight CST Monday night
for NEZ074>077-083>087.
Winter Storm Warning from 6 AM Sunday to midnight CST Monday
night for NEZ072-073-082.
Winter Storm Warning from noon Sunday to midnight CST Monday
night for NEZ039-040-046-047-060-061.
Ice Storm Warning from noon Sunday to midnight CST Monday night
for NEZ041-048-049-062>064.
KS...Ice Storm Warning until noon CST Monday for KSZ005>007-017>019.
&&
$$
UPDATE...Heinlein
SHORT TERM...Pfannkuch
LONG TERM...Pfannkuch
AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Grand Junction CO
755 PM MST Sat Jan 14 2017
.UPDATE...
Issued at 755 PM MST Sat Jan 14 2017
Visibilities are beginning to decrease across the same northern
valleys that have seen dense fog over the past several nights as
well as portions of the Central Gunnison River Basin. Areas of
dense fog will persist through at least 10 AM tomorrow morning.
Therefore, went ahead and hoisted a Dense Fog Advisory for these
areas and updated the grids accordingly. Visibilities are also
decreasing in and around Telluride, but will hold off on issuing
any highlights at this time and continue to monitor the situation.
UPDATE Issued at 454 PM MST Sat Jan 14 2017
All highlights will be allowed to expire at 5 pm this evening with
diminishing returns on radar fitting trends in HiRes RAP and HRRR
models. Still expect snow showers through the night, but
significant accumulations no longer expected in highlighted areas.
Fog has also lifted some across northwest Colorado with
visibilities generally above 3 miles, so the Dense Fog Advisory
will also be allowed to expire at 5 pm. Little more separation
between the T/Td at the moment, although another round of dense
fog is not out of the question later tonight as temperatures start
to cool back down.
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 338 PM MST Sat Jan 14 2017
The upper level low pressure system is currently situated just off
the Baja and making its way inland. During the late morning and
early afternoon hours, an enhanced band of precipitation moved
across southwest Colorado and southeast Utah producing heavy snow
in the mountains with rates of up to 3 inches per hour over the
San Juans, where winter highlites remain in place through 5 pm
today. The lower valleys south of I-70 were primarily affected
and precip type stayed rain for the most part with a few spots
mixing in briefly with snow. Current radar and satellite trends
show that this band has since weakened and is pretty much losing
its characteristics as it is moving into an area of more stable
air north of I-70. This area north of I-70 has been seeing areas
of fog, some of which has been dense throughout the morning and
early afternoon. Visibility has since improved as of 3 pm but
current guidance shows fog setting back in mainly across the
northern valleys overnight through Sunday morning. Later shifts
will have to look into the possibility of dense fog occurrence
once again given the moist low levels. Precipitation intensity
has also lessened this afternoon as well and expect a general
downward trend in shower activity this evening. Some convection
and thunderstorms are rotating around the low across Arizona and
southwest New Mexico, but do not expect this thunderstorm
activity to sustain itself by the time it makes its way northward.
Models appear to indicate an overall downturn in precipitation
this evening into the overnight hours for most areas. The
exception to this is a batch of showers left over from convective
activity passing through Arizona and New Mexico that will move
through southeast Utah. As the upper low shifts further east
across northern Mexico overnight into Sunday morning, some more
moisture looks to rotate up through southwest Colorado towards
Sunday morning. The H7 flow will shift around to the east which
tends to favor the eastern slopes of the eastern San Juans. It
appears this wave will clip the eastern portion of the western San
Juan mountains mainly up through Wolf Creek Pass and maybe Pagosa
Springs. It will be brief with weak forcing so maybe a couple
inches of snow for the western San Juans. A secondary shortwave
will move down the west coast on the back side of this low
pressure trough with some jet energy, helping to quickly push this
low further eastward as it lifts across Texas. This low is a bit
further south and east than previous models indicated which does
not favor our CWA for significant precipitation. Trended back the
pops by lowering them the further west and north you go during the
day on Sunday. Thinking that some light snowfall will continue but
additional accumulations appear minimal and gradual throughout
the day with no significant impacts. As said previously, the
eastern San Juans are favored in this upslope type of flow with
the western San Juans being quite shadowed. The orographic lift is
not overly strong enough to allow much significant snow to spill
over into our western San Juan mountains. Northerly flow takes
hold Sunday evening into Monday morning, bringing much drier air
into the region and putting an end to most precipitation.
Based on the above reasons, elected to let the current winter
highlites expire at 5 pm and will not continue or issue any for
the upcoming wraparound precip on Sunday. Snow will continue in
some areas, but accumulations are expected to be light.
.LONG TERM...(Monday through Saturday)
Issued at 338 PM MST Sat Jan 14 2017
Some light snow may linger over the San Juans Monday morning
favoring the north facing slopes but overall precipitation will be
coming to an end across the area as drier air advects in under
northerly flow. Some cooler air will be in place as well on Monday
following the final passage of this lingering storm system.
High pressure will build across the west and lay across the
region from west to east early this coming week, providing dry
conditions for most the region through Wednesday. A weak
shortwave looks to clip the northwest Colorado mountains on
Tuesday with mainly an increase in clouds and the slightest chance
of light snow. Temperatures should moderate by Tuesday into
Wednesday with values closer to normal if not slightly above as
warm air advection takes place ahead of the next series of storms
set to impact the region later this coming week. So before this
occurs, it looks like a dry and quiet period will be in store from
Monday through Wednesday.
Clouds will increase on Wednesday as the flow shifts to the west
ahead of the next series of Pacific storms making landfall onto
the Pacific Northwest and northern California coast. The first in
a series of storms moves across the region Thursday morning
through Friday morning with another one on its heels Friday
afternoon through the weekend. This second one looks stronger as
it deepens and forms a closed low on the lee side of the Rockies.
Details are a little fuzzy since this is a ways out and models
have a tendency to change, but overall it looks like an active and
unsettled pattern takes shape Thursday through the weekend with
more snow in the mountains and a rain/snow mix in the valleys
initially on Thursday, possibly changing to all snow by Friday as
H7 temps lower to around -8C by Friday morning and range from -10C
to -12C by the weekend. Moisture with this next series of storms
is modest but not overly as impressive as the previous atmospheric
river event that kept the weather active the first two weeks of
January. Specific humidity values with this next series of storms
range from 2.5 to 3.5 g/kg. In comparison, the two week long
atmospheric river event averaged about double this amount.
Stay tuned!
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 454 PM MST Sat Jan 14 2017
A Pacific storm passing to the south will continue to generate
precipitation south of the I-70 corridor through Sunday morning.
This will result in prolonged periods where CIGS are below ILS
breakpoints for all sites along and south of Interstate 70. In
addition, areas of MVFR and IFR CIGS and VSBYS will be common with
showers and fog moving through the region. Fog appears most likely
at KVEL, KCAG, KHDN and KSBS tonight with patchy fog in the
vicinity of KGJT, KRIL, KEGE and KMTJ. Conditions improve from
northwest to southeast after 18Z/SUN.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Dense Fog Advisory until 10 AM MST Sunday for COZ001-002-005-011.
UT...Dense Fog Advisory until 10 AM MST Sunday for UTZ024.
&&
$$
UPDATE...MMS
SHORT TERM...MDA
LONG TERM...MDA
AVIATION...JDC
Area Forecast Discussion
National Weather Service Lincoln IL
904 PM CST Sat Jan 14 2017
.UPDATE...
Issued at 850 PM CST Sat Jan 14 2017
No significant changes being made this evening in the short term
forecast or any of the headlines that are currently out.
Weak high pressure was centered over central Illinois this
evening with quite a bit of cloud cover across the forecast area.
Only exception was over our northern counties where skies have
cleared with a slow southward shift in the clearing trend noted in
the satellite data and surface observations over the past couple
of hours. Further south, we still have a solid stratus deck south
of I-72 with the possibility for some drizzle or freezing drizzle
coming out of the lower clouds at times overnight. However, have
not received any reports of that this evening but will keep an eye
out for that.
The next wave of freezing rain with even some isolated thunderstorms
was located over southwest Missouri this evening. Latest RAP and
HRRR models indicate the bulk of that precip will affect parts of
southwest through southern Illinois by morning. Will see some light
ice accumulations (less than a tenth of an inch) from that, but
like today, afternoon temperatures will be at or a couple of
degrees above freezing. Further north towards the I-74 corridor,
we will have a tough time getting much precipitation that far
north until late in the day or at night. For the most part, the
forecast has a good handle on the overnight trends but will make
some minor adjustments in the timing of the precip across our far
west tomorrow morning. We should have the updated zones out by 915
pm.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 300 PM CST Sat Jan 14 2017
Batch of light freezing rain exited east of east central IL early
this afternoon with a weak short wave. Though low stratus clouds
with bases of 500-1500 ft and a light fog from IL river southeast
could have patchy freezing drizzle with surface temps of 28-32F over
central IL at mid afternoon. Just patchy drizzle over southeast IL
along and southeast of I-70 where temperatures were 34-38F. 1035 mb
canadian high pressure was over eastern SD and ridging into the
Midwest and light nw winds trying to bring in drier air. Dewpoints
range from upper teens to mid 20s nw of the IL river, to the mid 30s
in southeast IL. Added patchy fog to southeast IL tonight and into
central IL as well overnight as temps cool toward dewpoints and
winds remain light with abundant low level moisture from recent
precipitation.
The second round of wintry precipitation will arrive across SW IL
including far SW CWA sw of Springfield and Lawrenceville late
tonight, and over rest of the CWA during the day Sunday, likely not
reaching the northern CWA until during Sunday afternoon. Cooler lows
overnight range from lower 20s nw of IL river, to the upper 20s to
near 30F in southeast IL. The latest forecast models continue slower
spreading qpf into central IL and cooler temperature profile trends.
850 mb temps are forecast to be zero to plus 2C over northeast CWA
on Sunday and may see more of a mix of light snow and sleet
especially from I-74 ne before changing to light freezing rain after
sunset Sunday. Surface temperatures rise to similar readings as
today, with lower 30s over IL river valley, and upper 30s in
southeast IL where mix pcpn Sunday morning turns to all rain Sunday
afternoon.
The freezing rain advisory for Fulton, Tazewell and McLean counties
will be cancelled as well as for Clark, Jasper, Richland, Lawrence
and Crawford in southeast IL where temps are above freezing thru
this evening. The Winter Storm Watch for northern CWA will be
converted to a Winter Weather Advisory Sunday night and Monday
morning and include areas from Fulton, Tazewell and McLean counties
north. Will continue the Freezing Rain Advisory for rest of CWA
through noon Sunday for light ice accumulations up to a tenth of an
inch or less, highest amounts in sw CWA where highest pops are by
Sunday morning.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 300 PM CST Sat Jan 14 2017
Precipitation expected to push northward Sunday night as increasing
southerly flow develops ahead of a low approaching via the southern
Plains, currently moving into northern Mexico. Southeasterly winds
at the surface will allow temperatures to start an increasing trend,
but still expecting freezing temperatures for at least portions of
the night from I-70 northward causing continued potential for
freezing rain as well as a mix of sleet and snow. Temperatures will
rise above freezing by about mid morning in the vicinity of I-74
then temperatures should remain above freezing for at least the next
day...until Tuesday night. Planning on issuing a winter weather
advisory from Sunday evening through Monday morning from Fulton to
Mclean county northward for the mix of ice, sleet, and snow.
With the strong low approaching the northwest corner of Illinois by
Monday night...increased chances for rain will also develop along
with the increased temperatures...with amounts around 1/2 to 3/4
inch likely from Monday morning to noon Tuesday. MUCAPE values in
the 200 J/kg range associated with the warm sector southeast of the
low imply thunderstorms possible so have included slight chance of
thunderstorms starting Monday afternoon southwest of Springfield,
then across central IL Monday evening...then shrinking down to I-70
southward Monday night.
Only a brief pocket of cooler air will affect central IL Tuesday
night through Wednesday night with lows in the upper 20s to mid 30s
and highs in the 40s followed by warm advection ahead of the next
low pressure system. Highs thursday through Saturday should increase
into the 50s. After dry weather midweek...there is a chance for rain
by Friday, although model inconsistencies this far out imply low
predictability.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 510 PM CST Sat Jan 14 2017
Drier air continues to slowly work its way south into our area in
the wake of the weather system that brought the freezing rain to
the forecast area this morning and early this afternoon. As a
result, we have seen cigs improve to VFR at PIA with mainly
MVFR cigs at the other TAF sites. RAP forecast soundings suggest
improving conditions from north to south late this evening where
we may see a temporary VFR cig further south at SPI, DEC, and CMI.
Low level moisture will remain in place so if we do clear out for
a time later tonight, we may see vsbys come down to MVFR in fog
during the early morning hours. The next weather system will
start to approach SPI by 11z-14z with another round of -FZRA
possible during the morning hours along with cigs lowering to IFR.
Winds are going to remain light through the forecast period,
mainly from the north tonight around 5 kts and winds will shift
into an easterly direction on Sunday with speeds again around 5
kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Freezing Rain Advisory until noon CST Sunday for ILZ040>057-061-
062-066-071.
Winter Weather Advisory from 6 PM Sunday to noon CST Monday for
ILZ027>031-036>038.
&&
$$
UPDATE...Smith
SHORT TERM...07
LONG TERM...37
AVIATION...Smith
Area Forecast Discussion
National Weather Service Jackson MS
936 PM CST Sat Jan 14 2017
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
A small region of patchy fog was added to the Delta as METAR
observations continue to show low visibility. Otherwise no other
modifications have been made to the latest forecast update./12/
Prior discussion below:
and little to no precipitation has allowed dewpoints this afternoon
to mix out 5 to 10 degrees lower than this time yesterday. While
there was some dense fog this morning over the south, visible
satellite imagery this morning showed that it was mainly confined to
river channels and the usual fog problem spots. It seems as though
the HRRR is aware of this as it is showing the only area for possible
dense fog tonight along and just behind the quasi-stationary frontal
boundary skirting the northern portions of the forecast areas. This
makes sense as latest surface data is indicating the best moisture
pooling near the boundary. Still, believe most areas will see some
fog tonight, but it will be the northern portions and the usual fog
problem spots that see anything potentially dense.
Mid level ridging will continue the string of abnormally warm days
for Sunday as highs reach into the mid and upper 70s. The exception
will be over the far northwest where cooler air and cloud cover
behind the boundary will keep readings in the mid 60s./26/
Sunday Night through Friday: For Sunday night we will start with
another late night with some patchy fog across the region. Mild
conditions will continue through the period with better chances of
rain as we move through the work week. A low pressure system coming
out of the Southern Plains will drag a surface low with it to the
Great Lakes Region. This will bring a front to our western area by
early Tuesday. The front will push across the region on Tuesday and
will settle across our southern counties on Tuesday evening. After
that it seems to become quasi-stationary around our southern counties
for Wednesday and Thursday. Models have different opinions on when it
pushes back to the north on late Thursday into Friday. This will
occur as our focus shifts to the Southern Plains where a storm system
will be developing. Not to mention the different timing of the
shortwaves and their amplitude coming across the region in this split
flow pattern. However pwats will build from 1.5 to 1.7 inches with
the frontal boundary around, which will give some opportunities of
some locally heavy rainfall. However with such diversity of model
solutions confidence is rather low. One thing is for certain we will
get rounds of showers and some thunderstorms during most of the
period with the passing disturbances. This was shown by both the
European and GFS ensembles. Do not see any organized severe potential
for the period.
Looking ahead the Canadian,GFS, and Euro shows a strong system
coming out the Southern Plains which may affect the region for next
weekend. The models have a different scenario but it bears watching.
/17/
&&
.AVIATION...
00Z TAF discussion: VFR conditions were observed at all TAF sites at
00Z and VFR conds will prevail through 06Z. After 06Z areas of fog
and low clouds will begin developing with flight categories falling
through MVFR to IFR by 15/09Z at GLH/GTR and HBG. Elsewhere, MVFR
visibilities can be expected by morning, but somewhat drier air in
the lower levels should prevent the fog from becoming widespread and
dense as last night. /26/22/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 52 76 57 76 / 2 4 9 21
Meridian 50 76 56 76 / 3 4 6 18
Vicksburg 51 73 58 75 / 3 5 12 26
Hattiesburg 51 77 58 77 / 3 5 7 17
Natchez 53 75 59 76 / 3 7 14 25
Greenville 50 70 55 71 / 4 7 12 43
Greenwood 51 73 57 74 / 4 6 9 30
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
12
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
834 PM CST Sat Jan 14 2017
.UPDATE...
Issued at 819 PM CST Sat Jan 14 2017
Next batch of freezing rain moving through southwest MO this
evening. Even a few lightning strikes in this area of
precipitation. Looking at the latest radar loops and HRRR model
runs it appears that this precipitation will move into parts of
central and southeast MO by late evening, then impact areas along
and south of I-70 overnight. Until this area of mainly freezing
rain moves in later tonight there will be patchy fog and freezing
drizzle.
GKS
&&
.SYNOPSIS...
Issued at 254 PM CST Sat Jan 14 2017
No changes to current headlines with ice storm warnings continuing
into Sunday. Next main wave of precipitation/freezing rain
spreads into the area after midnight and impacts the region
through Sunday morning, diminishing Sunday afternoon. Additional
ice accumulations generally 0.10-.20 with localized area near 0.25
inches.
&&
.SHORT TERM... (Through Late Sunday Afternoon)
Issued at 254 PM CST Sat Jan 14 2017
Focus thru this period continues to be the impending icing event.
Ongoing rain will continue across extreme srn portions of the CWA
thru this afternoon. Can not rule out a passing shower this evening
across this region, but believe much of the evening will remain dry.
A s/w currently over nrn TX/wrn OK region is progd to lift enewd
today and tonight. This is expected to spread precip into the area,
mainly after Midnight tonight. However, mdls depict enuf forcing to
indicate some light precip ahead of the s/w. After the first wave of
precip pushes thru the area Sun morning, precip shud refocus across
nrn and into central portions of the CWA.
As for temps, expect temps to drop a degree or two across the region
after sunset. Temps shud remain fairly steady overnight and may
actually rise a degree or so with onset of precip. Temps shud slowly
rise late Sun morning into the afternoon. Expect most of the CWA to
be aoa the freezing mark by 21z Sun, except far northern MO and
west central IL.
Given the temps expected thru Sun, may see an additional tenth or
two of ice accumulation at any given spot thru the period.
Tilly
.LONG TERM... (Sunday Night through Next Saturday)
Issued at 254 PM CST Sat Jan 14 2017
The main wave of significant precipitation from Sunday should have
shifted north of the CWA, or be close to exiting north of the CWA at
00Z Monday. In the wake of this wave, an additional precipitation
will be spotty or scattered on Sunday night with the highest
probability across northern MO into central IL. Surface temperatures
will generally be in the 31-33F range across northeast MO/west
central IL during the evening. Overnight however, temps should
uniformly warm above freezing as the surface high pressure dome
continues to retreat eastward from the Great Lakes region, surface
winds slowly veer and increase, and as upper flow exhibits
prounouced backing.
The models have come into better agreement in the Monday/Tuesday time
frame, then diverge some thereafter. The general consensus is the
primary upper low will lift northeastward through the central
Plains on Monday and into the Upper MS Valley on Monday night.
Correspondingly, the accompanying surface low will track into
northwest MO by 00Z Tuesday and into the western Great Lakes
region by Tuesday morning. Deepening and strengthening
south/southwesterly flow aloft and strengthening/veering surface
winds associated with the movement of the aforementioned upper
level and surface systems will transport unseasonably mild air
across the CWA on Monday/Monday evening ahead of the surface low
and advancing cold front. This will not only result in well above
average temps and melting to any residual ice, but will also help
promote enough instability to mention the possibility of embedded
thunderstorms as a band of rain/showers translates across the area
Monday/Monday night. The cold front should completely exit east of
the area by midday Tuesday with weak CAA in its wake and potentially
some "wrap-around" precipitation in northeast MO and west central
IL. The air in the wake of this front however is not all that cold
for January.
Temperatures moderate quickly by Wednesday as a WAA regime becomes
re-established and persists with varying degrees through the
remainder of the week. Temperatures looks to be well above average
Wed-Fri.
Glass
&&
.AVIATION... (For the 00z TAFs through 00z Sunday Evening)
Issued at 547 PM CST Sat Jan 14 2017
IFR or near IFR stratus clouds along with fog will continue
through the period. Another round of freezing rain will move into
the taf sites late tonight and continue Sunday morning.
Temperatures will warm up enough in COU and the St Louis metro
area to change the freezing rain to rain early Sunday afternoon.
Light northerly surface wind will veer around to an easterly
direction Sunday afternoon as the surface ridge over the northern
Plains moves eastward into the Ohio valley region.
SPECIFICS FOR KSTL: IFR or near IFR stratus clouds along with fog
will continue through the period. Another round of freezing rain
will move into the STL area late tonight and continue Sunday
morning. Temperatures will warm up enough to change the freezing
rain to rain early Sunday afternoon. The rain should end by Sunday
evening. Light northerly surface wind will veer around to an
easterly direction Sunday afternoon as the surface ridge over the
northern Plains moves eastward into the Ohio valley region.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Ice Storm Warning until 6 AM CST Sunday for Crawford MO-Iron MO-
Madison MO-Reynolds MO-Saint Francois MO-Sainte Genevieve
MO-Washington MO.
Ice Storm Warning until 3 PM CST Sunday for Audrain MO-Lincoln
MO-Monroe MO-Pike MO-Ralls MO.
Ice Storm Warning until noon CST Sunday for Boone MO-Callaway MO-
Cole MO-Franklin MO-Gasconade MO-Jefferson MO-Moniteau MO-
Montgomery MO-Osage MO-Saint Charles MO-Saint Louis City MO-
Saint Louis MO-Warren MO.
Ice Storm Warning until 6 PM CST Sunday for Knox MO-Lewis MO-
Marion MO-Shelby MO.
IL...Ice Storm Warning until 6 AM CST Sunday for Randolph IL.
Ice Storm Warning until 3 PM CST Sunday for Calhoun IL-Greene IL-
Jersey IL-Macoupin IL-Montgomery IL-Pike IL.
Ice Storm Warning until noon CST Sunday for Bond IL-Clinton IL-
Fayette IL-Madison IL-Marion IL-Monroe IL-Saint Clair IL-
Washington IL.
Ice Storm Warning until 6 PM CST Sunday for Adams IL-Brown IL.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Paducah KY
1000 PM CST Sat Jan 14 2017
.UPDATE...
Issued at 1000 PM CST Sat Jan 14 2017
As expected measurable rainfall has been very scarce this evening,
and will continue to be so into the overnight hours. An area of
rain over southwest Missouri is moving northeast and should not
reach our area until 09Z or so. Of course, the latest HRRR runs
are non-committal on whether or not it will reach our area. Held
PoPs at low chance levels until very late tonight before ramping
up to 50-60% in the northwest. Of course, this is where
temperatures will be right at the freezing mark, so will have a
mention of freezing rain. With temperatures expected right near
32F, figure any icing will be limited to elevated objects. With
little, if any, ice from yesterday left in these areas, the impact
should be nil. Have addressed this in the HWO and do not plan to
issue any extra products for this event.
There have been some very light echoes on area radars this
evening, and some lowered visibilities in METARs, indicative of
some light drizzle. With the rain in the forecast, just settled
for mentioning areas of fog, which is what we have seen here at
the office recently.
UPDATE Issued at 610 PM CST Sat Jan 14 2017
Updated aviation discussion.
&&
.SHORT TERM...(Tonight through Monday night)
Issued at 225 PM CST Sat Jan 14 2017
Have allowed winter/fog headlines to expire this afternoon as
vsbys have improved and surface temperatures have crept just above
the freezing mark over nw counties with precip shifting south
toward the OH River. Could be another batch or two of very light
rain or drizzle overnight tonight at many locations as the lower
atmosphere remains quite saturated. Not much forcing to work with
though, so any QPF should be quite light. Temperatures not
expected to fall off much during the night, but it would not take
much of a drop to get our northern/western counties of srn IL/se
MO back to near or just below freezing. Will need to monitor to
see how precip/temp trends go this evening up in those locations
for possible quick advisory for some freezing drizzle/light
freezing rain possibilities.
Weak mid level ridging on Sunday will also serve to keep any
significant amounts of precip out of the region, though will need
to leave some chance for a bit of very light precip, especially
along/north of the I-64 corridor. Again, would not be surprised to
see a touch of freezing precip in that corridor early in the day,
but will hold off on headlines at this time and handle with
HWO/possibly an SPS.
Next high chance of rain/isolated thunder looks to hold off until
later Mon/Monday night time frame as the next surface front and
associated H50 short wave approach from the west. Not too excited
at this time on strong/severe threat given overall lack of
instability. More likely just a few isolated rumbles of thunder
here and there. Could be some decent widespread rain amounts up
over 1/2 inch tho.
.LONG TERM...(Tuesday through Saturday)
Issued at 225 PM CST Sat Jan 14 2017
The northern hemispheric pattern has the center point of the wave
pattern shifted toward the Arctic circle northwest of Alaska at the
start of the extended forecast period, with the most dominant
meridional wave extending from the pole to east of Greenland and a
low amplitude, split trough over the Northern Pacific. The evolution
of the primary stable five wave pattern (per the ECMWF and GFS
guidance) into a 3-4 unstable wave pattern, suggest a more dynamic
and chaotic flow over the U.S. during the extended period. However,
the dominance of the mean trough east of Greenland/Northern
Atlantic, may mean greater heights upstream over the eastern U.S.,
pushing systems to the west of the WFO PAH forecast area further to
the west and north.
Although the GFS and ECMWF similarly handle the ejection of the Baja
California low into the western Great Lakes through Tuesday, the
similarity begins to wane with time, especially late in the week.
The 12z Saturday ECMWF is a little warmer aloft, but cooler at the
surface than the 12z Saturday GFS. A blend of ECMWF/GFS seems to be
a more realistic solution.
For the WFO PAH forecast area, this would be mean that the weather
system on Tuesday should exit a little quicker, with the system
moving from the southwest Thursday into Friday should be shifted
more to the east with time in a more progressive flow.
Blended max/min temperatures upward slightly from the cooler ECMWF
values, but still lower than the GFS. In addition, kept PoPs in
place closer to the slightly faster and more eastern ECMWF than the
warmer and more unstable GFS. There is lesser forecaster confidence
in the late week solution (40-50%) than the Tuesday weather system
(60-70%).
Otherwise, no significant changes in the other sensible weather
elements through the forecast period.
&&
.AVIATION...
Issued at 610 PM CST Sat Jan 14 2017
Weather conditions are expected once again to deteriorate overnight
with the diurnal cooling of the lower trop. Meanwhile, a wedge of
cool air near the surface will pivot eastward through the region,
causing some veering of the surface winds. IFR cigs are expected
soon, if not there already, and should go LIFR after midnight. Vsbys
should eventually go IFR sometime this evening in drizzle and fog,
with a chance of LIFR levels (not in TAFs currently). By mid morning
Sun, heights aloft will begin to rise, resulting in improving
conditions, albeit with rain showers, from southwest to northeast.
However, IFR cigs will probably remain through the end of the 00Z
TAF period.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...DRS
SHORT TERM...GM
LONG TERM...Smith
AVIATION...DB
Area Forecast Discussion
National Weather Service Blacksburg VA
641 PM EST Sat Jan 14 2017
.SYNOPSIS...
A weak cold front has drifted south of the region and will remain
south of the area tonight into Sunday and will drift back north of
the area Monday. Meanwhile, a series of disturbances aloft will
track over the region keeping clouds and periods of precipitation
across the region for several days. Finally, a stronger cold front
is slated to move through the region by the middle of next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 300 PM EST Saturday...
Arctic high pressure to our north will slide east tonight into
Sunday. The high center pushed colder air pushing into our region.
The frontal boundary has moved south of us and was located across
Georgia and South Carolina this afternoon. A wave of low pressure
will ride east tonight into Sunday. Regional WSR-88d images showed
an area of rain off to our west mainly north of the Ohio River.
This feature will rotate east tonight into Sunday. Utilized a blend
of the HRRR and Hiresw arw-east for this afternoon into tonight
because they capture this precipitation best. Then, blended in the
nam for pops overnight into Sunday. In general, the Models seem to
focus more activity west in the Tennessee valley overnight/early
Sunday. At any rate, there will likely be patchy of fog and drizzle
when it is not raining with low level moisture. With a non diurnal
temperature curve, low temperatures range from the lower 30s in the
northwest Greenbrier county to the mid 50s in the southwest
mountains. With temperatures close to freezing in western Greenbrier
county, there is a slight chance for freezing rain late tonight
into early Sunday morning.
The low level wedge across the region Sunday morning will weaken as
the flow turns more northwest behind a weak exiting wave offshore.
This may result in some drying especially across central and eastern
portions of the forecast area Sunday before another transient but
weaker surface high starts to build in from the north. Another Mid
level shortwave will rotate east returning precipitation to the west
and spreadings east by late Sunday. High temperatures Sunday will
vary from around 40 degrees in the northern mountains to the
lower to mid 50s along the southern Blue Ridge mountains.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 330 PM EST Saturday...
Split flow pattern over North America will persist through
Tuesday. This will keep our forecast area pinned between the
colder northern stream westerlies to our north and subtropical
warmth along the Gulf Coast. Closed southern stream low over the
southwestern CONUS will be the focus for pieces of short wave
energy which will eject east, resulting in period lift along a
wavy surface front which bisects the Mid-Atlantic from west to
east, dividing the colder air associated with the northern
stream from the warmer subtropical air to our south. Result will
be abundant cloud cover with the potential for rain and/or
drizzle.
Highest potential for rain during this time frame will be
Sunday night and again Tuesday night, with widely scattered
showers in between. Sunday night, models indicate about a 6-8
hour period of isentropic lift promoting 60-80 percent chance of
rain, the highest pops vicinity of the blue ridge where lift
will be maximized from the easterly low level wind field. Can`t
rule out an hour or two of freezing rain/drizzle early Monday
morning at the highest elevations along the Blue Ridge (Peaks of
Otter and points north along the Blue Ridge Parkway) where
temperatures will test 32 degrees. Elsewhere, just looking at a
cold rain.
Surface front will get a nudged north Monday into Tuesday, so
temperature trend Monday into Tuesday should be up, with steady
or increasing temperatures, from 40s Monday, steady or rising
Monday night (40s/50s), testing 60 on Tuesday.
Closed low over the southwest is expected to eject northeast
into the upper Mid-West by Wednesday. This will send a surface
front east bound, this feature approaching our area Tuesday
night. Convergence along the front will likely result in another
period of rain or rain showers, beginning as early as Tuesday
evening in the mountains, then spreading east across the
forecast Tuesday night.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 345 PM EST Saturday...
Surface front is forecast to cross the forecast area early
Wednesday. Attm, models do not indicate much in the way of cool
air behind the front, a few degrees drop at 850 mb, so once we
dry out behind this feature Wednesday, the afternoon should be
fairly nice with Temperatures once again testing 60.
Beyond Wednesday, the weather pattern still looks mild. A new
cutoff low is forecast to take up residence within the southern
stream over the southwestern CONUS with ridging over the
southeast States and Gulf Coast. There are some model
differences with respect to how far east the southern stream
trough will progress next weekend. This results in timing
differences with respect to precipitation. Per the mild
pattern, there should not be any P-type issues for our forecast
area with any precipitation falling in the form of rain.
Forecast high temperatures will run about 10- 20 degrees above
normal Wednesday through Saturday.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 636 PM EST Saturday...
Overall poor flying conditions will continue tonight as a
wedge of high pressure locks in along and east of the mountains.
Low clouds with patchy light rain and drizzle will combine to
produce IFR/LIFR cigs and MVFR/IFR vsbys in the mountains and
MVFR out east where cloud bases should remain higher and
rainfall less. Pilots should prepare for Mountain Obscurations
into Sunday.
Medium to low confidence with cigs and vsbys through Sunday
given varying conditions in and out of the wedge through the
weekend. Spotty nature of fog and drizzle is also problematic.
Higher confidences that east to southeast winds will prevail on
Sunday.
Extended Aviation Discussion...
A baroclinic zone will remain anchored across the region
sandwiched between a strong upper ridge over the southeast
states and an active jet stream from the southwest U.S. into the
northeast U.S. Thus, an unsettled, wet weather pattern is
expected to remain in place Monday into Tuesday. The frontal
boundary may lift north enough by Monday night for a brief
period of mainly VFR, but a stronger front will arrive By
Tuesday with more showers including widespread sub-VFR.
Generally looking at MVFR much of the period, although periods
of VFR as well as IFR- LIFR can be expected at times. Passing
cold front from later Tuesday should clear the region on
Wednesday allowing for a return to VFR across the region for
midweek. Moisture may return from the southwest Thursday
afternoon into Thursday night.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK
SHORT TERM...PM
LONG TERM...PM
AVIATION...JH/KK/RCS
Area Forecast Discussion
National Weather Service Topeka KS
940 PM CST Sat Jan 14 2017
.UPDATE...
Issued at 940 PM CST Sat Jan 14 2017
The radar at 02Z showed 925MB winds were still from the north
indicating there may be some low level dry air advection still
occurring. With the 00Z NAM and 18Z GFS showing little in the way
of strong synoptic forcing until late in the day Sunday, have been
looking at isentropic surfaces for signs of lift and forcing for
precip. However profiler data shows the stronger more southerly
winds remain well to the south over TX while 850 winds over
eastern KS are still veered to the southwest. This doesn`t seem
very favorable for moisture advection into northeast KS. Because
of this have trended POPs down 10 to 20 percent and precip
overnight may be more the isolated/scattered nature than a
widespread shield of precip. Will continue to monitor trends and
adjust.
UPDATE Issued at 537 PM CST Sat Jan 14 2017
Light north winds at the surface suggest there may still be some
weak dry air advection going on and the light freezing rain
appears to be fighting this dry air based on recent radar trends.
00Z sounding that just went up shows this dry layer to be about
2500 feet deep. because of this have delayed the onset of precip a
few hours. Latest RAP shows low level isentropic lift increasing
on the 295K surface around 03Z and this is when the freezing
precip is anticipated to spread further north into the forecast
area.
&&
.SHORT TERM...(This evening through Monday)
Issued at 331 PM CST Sat Jan 14 2017
Current satellite shows holes in the cloud cover that have caused
temperatures to warm into the mid 30s. Slight isentropic downglide
has contributed to this drying, but has kept the dew points much
lower. The only exception would be far eastern KS where the moisture
is deeper and closer to the ground. An area of showers and rain is
moving towards the area from the southwest. It should arrive in the
forecast area late this afternoon and evening. Wet bulbing due to
evaporation should cool the temperatures into the 20s and lower
30s therefore resulting in freezing rain once the column saturates.
Some of the high res models are struggling with this batch of
precipitation by either eroding it away or tracking it south of the
forecast area. They are also underestimating the precipitation
coverage. There is a chance that once freezing rain begins it might
not stick to objects or pavement until conditions cool this evening
and wet bulbing is finished. Also, temperatures are forecasted to
cool a few degrees in general due to the loss of daytime heating.
Most of the area stays below freezing before sunrise tomorrow
morning.
Larger scale models bring a continuous stream of precipitation in
the form of freezing rain tonight for areas mainly along and south
of I-70. This is when these areas could receive significant icing.
While more isolated to scattered freezing rain showers are possible
north of I-70. By late tomorrow morning the freezing rain may still
be ongoing for most of the area. Temperatures will begin to warm to
near freezing starting in east central KS, and that trend will
gradually move northward into the afternoon. This will be the tricky
part of the forecast since a few degrees separates freezing rain vs
rain. The models are now hinting that the majority of the
precipitation tomorrow late morning and onward will fall along and
north of I-70. This is when these areas could receive significant
icing. Light precipitation is still possible elsewhere during this
time frame. There could be a lull Sunday evening and overnight
before the main upper level low pressure lifts out over the plains.
By this time a majority of the area may be above freezing. Although
there is a chance that portions of north central KS could stay in
the freezing rain. This would cause higher amounts in these areas by
Monday morning. Generally ice amounts will be between 0.25" and
0.75" with locally higher amounts possible.
A closer look of at the 12z GFS ensembles show that the operational
GFS has some of the warmest temperatures by a few degrees out of all
of the members. Also, the 18Z NAM keeps wet bulb temperatures below
freezing for a majority of the area through tomorrow evening. The
operational GFS has the some of the lowest total QPF compared to all
of the ensemble members for northeast KS through tomorrow night. The
orientation of the 850 mb low level jet would suggest strong
moisture convergence to support this widespread precipitation
through tomorrow. Neutral advection at the surface under light
northeast winds would suggest steady temperatures. Not sure how much
mixing of the warm nose down to the surface will actually take
place. All of these factors would lead me to believe that widespread
significant ice accumulations as still possible.
.LONG TERM...(Monday night through Saturday)
Issued at 331 PM CST Sat Jan 14 2017
On Monday night the upper level low will move overhead and off to
the northeast. There is some potential for moisture to wrap around
the low, interact with an incoming weak vort max from the
northwest, and possibly support a last shot of a light wintery
mix of precipitation. Chances for anything to accumulate are low
and additional impacts are unlikely but will continue to monitor
this period in case deep moisture and lift are a bit stronger or
if the upper low moves out a bit slower.
Temperatures warm markedly for the rest of the forecast period.
Several negatively tilted upper level short wave troughs will
cross the Plains between Thursday and next weekend, but moisture
return will be limited prior to the weekend. For now have only
very small pops for the system on Friday, which looks to have warm
temperatures to support rain if precip develops. The late weekend
storm system looks potentially more interesting but the current
storm track looks to have the local area on the warm side of
things.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday)
Issued at 537 PM CST Sat Jan 14 2017
Don`t have a great deal of confidence in IFR VSBY and CIGS just
yet as precip continues to battle the dry air at the surface.
Since the RAP and HRRR tend to favor an MVFR forecast, have leaned
that way for a little longer into the evening. However continued
moisture advection over the surface high should lead to IFR CIGS
so have followed the bulk of the guidance and bring CIGS down.
Timing the freezing rain and when CIGS worsen is the biggest
uncertainty and have generally followed the consensus. However
amendments are likely as the event unfolds.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Ice Storm Warning until midnight CST Sunday night for KSZ024-026-
035>040-054-055.
Ice Storm Warning until noon CST Monday for KSZ008>012-020>023-
034.
Ice Storm Warning until noon CST Sunday for KSZ056-058-059.
&&
$$
UPDATE...Wolters
SHORT TERM...Sanders
LONG TERM...Barjenbruch
AVIATION...Wolters
Area Forecast Discussion
National Weather Service Tulsa OK
922 PM CST Sat Jan 14 2017
.DISCUSSION...
Freezing Rain Advisory was previously extended through tonight,
and current trends support keeping the Advisory along with the Ice
Storm Warning configuration as they are. Additional light to
moderate precip has begun expanding across east central OK and
will continue to expand northeast over the next few hours, a
trend supported by most hi-res models along with the 00z NAM.
Surface temps are not likely to change much overnight, though an
overall rise of a degree or so continues to be shown in most model
guidance. Still this supports additional icing in many areas north
of I-44 with heaviest accretions remaining near the Kansas border
where sfc temps should remain a tad lower. It is likely that some
areas will not warm above the freezing mark until after the
warning expiration time of 12z...however signal has remained
consistent that precip should decrease by that time and for the
moment, feel that the current expiration time will suffice.
Updated products have already been sent.
&&
.PREV DISCUSSION... /Issued 542 PM CST Sat Jan 14 2017/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Ongoing IFR to LIFR conditions will continue through much of the
forecast period with some improvement possible Sunday afternoon.
Precip chances will remain highest for NE OK with periods of FZRA
continuing through tonight for KBVO.
PREV DISCUSSION... /Issued 312 PM CST Sat Jan 14 2017/
DISCUSSION...
Earlier update had removed the Ice Storm Warning for a few
counties in northeast OK and replaced with a Freezing Rain
advisory as 32F line has held steady from north of Pryor to Tulsa
to northern Creek county. Some additional light icing will occur
in these areas the remainder of the afternoon...with surface
temperatures expected to rise just a hair above freezing by this
evening.
A large area of freezing rain has blossomed across much of
western and northwestern OK...the eastern fringes of this activity
will impact areas northwest of I-44 this evening and into the
overnight hours. Latest high-res NAM solutions look just a touch
too warm with the surface temps in these areas...although the HRRR
appears to have a reasonable handle. Plan on keeping the Ice Storm
warning going for Pawnee...Osage...Washington...Nowata and Craig
counties...with the most significant icing occurring in parts of
Osage county near the KS border. Obviously this is very
temperature dependent...and if any warming occurs then icing will
decrease accordingly.
Surface temperatures will warm above freezing by Sunday
morning...in advance of a strong upper cyclone moving into west
TX. Rapid moisture return ahead of this system will bring a very
good chance of widespread showers and a few storms to the area
mainly Sunday night into Monday. Mass synoptic fields suggests
that the primary warm sector remains most to our south for this
event...so overall chances of thunder and any severe storms will
be quite limited.
The upper pattern remains quite active across the CONUS for next
week...although the better moisture should be shunted south.
Seasonal temperatures on Tuesday will be followed by a nice
warming trend the rest of the week. Have kept the extended portion
of the forecast dry for now.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 33 52 51 63 / 80 30 80 40
FSM 44 61 52 67 / 30 20 60 70
MLC 37 60 57 67 / 60 30 90 60
BVO 31 48 46 61 / 90 60 80 40
FYV 41 57 52 62 / 50 30 60 70
BYV 38 53 48 63 / 60 30 60 70
MKO 34 55 52 67 / 80 30 80 60
MIO 31 51 49 63 / 80 60 80 60
F10 33 55 54 65 / 80 40 80 50
HHW 46 64 56 68 / 20 20 90 80
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Freezing Rain Advisory until 6 AM CST Sunday for OKZ058-060-061-
064.
Ice Storm Warning until 6 AM CST Sunday for OKZ054>057-059.
AR...None.
&&
$$
SHORT TERM...14
LONG TERM....99