Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/08/17
Area Forecast Discussion
National Weather Service Bismarck ND
933 PM CDT Sat Oct 7 2017
.UPDATE...
Issued at 925 PM CDT Sat Oct 7 2017
Did pick up a trace of rainfall here at the Bismarck airport
earlier this evening with the very light rain showers across the
southwest and south central. The CAMs through the 01 UTC HRRR seem
to have a good depiction of this area of light precipitation and
will follow their solutions which continue the very light rain
chances through around 10 UTC across the James River Valley.
UPDATE Issued at 640 PM CDT Sat Oct 7 2017
Little change with this update other than for observed trends
through 23 UTC. Isolated showers are possible across the Turtle
Mountains for the next 1-2 hours in association with weak impulses
along the international border.
UPDATE Issued at 440 PM CDT Sat Oct 7 2017
Sustained winds and/or wind gusts not meeting wind advisory
criteria, thus will cancel it. Updates to text products coming
shortly.
UPDATE Issued at 439 PM CDT Sat Oct 7 2017
Sustained winds and/or wind gusts not meeting wind advisory
criteria, thus will cancel it. Updates to text products coming
shortly.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 402 PM CDT Sat Oct 7 2017
A cold frontal passage with an ongoing wind advisory into early
this evening is the main highlight of the short term period. Cold
front stretched from southern Manitoba into the Turtle Mountains
and across central/western ND. Temperatures are in the upper 60s
with lower 70s south central. Bismarck VAD wind profile shows
30kt winds between 3kft and 8kft above the ground. BUFKIT soundings
show mixing heights to around 8kft south central ND. Wind advisory
is marginal but will keep it going this afternoon since a couple
sites have manage to achieve criteria, and possible some more
before sunset.
Latest suite of satellite imagery and surface observations show an
elongated 300mb 130kt jet stretched out along the US/Canadian
border/north central ND, west to the British Columbia coast.
Model/satellite data confirms a couple of jet streaks within the
strong corridor of winds aloft. Latest regional radar shows
increasing showers in southern Saskatchewan, close to our northern
border associated with the nose/left exit region of 130kt jet
mentioned above. Other showers were forming in north central MT
and moving east with time. Through 06z Sunday, it will be a
combination of jet dynamics, multiple mid level shortwaves, and
low level instability contributing to upward vertical motion and
isolated showers. Low level instability/steep lapse rates will
continue through the evening as a cold pocket of air at 850mb,
reflection the cold front aloft, begins to push across northwest
ND. The 850mb front then slides into south central ND and into the
James River Valley by 06z Sunday. With a variety of model
solutions on location/timing/longevity of potential showers, have
favored an areal coverage mentioning isolated showers across the
south versus scattered at this time. The evening shift can monitor
for changes and adjust.
Cooler Sunday with highs in the 50s and northwest winds 10 to 20 mph.
There could be a brief shower or two in the north cental and northwest
during the afternoon, along and ahead of a secondary cold front.
Current gridded forecast has this in there, dry elsewhere.
.LONG TERM...(Sunday night through Saturday)
Issued at 402 PM CDT Sat Oct 7 2017
Will likely need a freeze warning west and most of central ND
Sunday night/early Monday morning, and all of western and central
ND Monday night/early Tuesday morning. Based on current forecast
low temperatures early Tuesday morning, some areas will see a
hard freeze, while others will not. For a hard freeze, temperatures
will have to reach at least 28F or colder for 3 hours or more.
Columbus day Monday will be cold. Normal high temperatures are
around 60F for western/central ND; expect highs in the mid to
upper 40s with northwesterly winds 10 to 15 mph. The weather
pattern is active in terms of temperature swings, but not in
precipitation potential. A warmup Tuesday and Wednesday with
highs getting into the upper 50s Tuesday, then upper 50s/lower 60s
Wednesday. A cold front sweeps across western/central ND during
the day Thursday with cooler air for Friday and Saturday. Perhaps
better chances for precipitation by Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 925 PM CDT Sat Oct 7 2017
VFR conditions are forecast across western and central North
Dakota for the 00 UTC TAF cycle. Very light rain showers are
possible across southern North Dakota tonight.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PA
SHORT TERM...KS
LONG TERM...KS
AVIATION...PA
Area Forecast Discussion
National Weather Service Cleveland OH
934 PM EDT Sat Oct 7 2017
.SYNOPSIS...
A cold front will move east across the area tonight. A ridge of
high pressure from the mid Atlantic states will extend northwest
into the area Sunday. The tropical remnants are expected to move
northeast out of the Gulf of Mexico toward the Tennessee Valley
region by Sunday night. This feature will bring a swath of more
rain to the local area Sunday night into Monday morning. High
pressure will build east across the northern Great Lakes from the
northern plains states by midweek as yet another low pressure system
moves north out of the deep south toward the area.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
Minor adjustments to pops with the late evening forecast update,
otherwise no major changes. Previous forecast thinking remains
largely on track, as thin line of showers and a few rumbles of
thunder tracks into NW OH. Upstream wind reports have still been
on the low side, with up to 40 kts reported, but mainly in the
35 kt range. Latest hi res model trends point to the initial
line spreading northeastward into the area, currently from near
Cincinnati up to just south of Toledo. This may become the
dominant precip maker, associated with a fairly potent low level
jet max surging northeastward. The latest HRRR shows this jet
feature increasing to around 75 kts as it moves NE into NW OH
and western Lake Erie over the next two hours. Will continue to
monitor for the potential of strong convective wind gusts, and
an SPS may be needed to handle the threat. Not anticipating any
widespread severe gusts at this point, and the weak tornado
potential seems to be confined to southwest OH at this point,
where the greatest instability and effective SRH max is located.
Previous discussion...
Focus is shifting to convective potential this evening, as
gradient winds have subsided just a bit. Broken line of rather
intense showers w/ scattered thunder continuing to track east
through Indiana. So far, upstream wind reports are yet to exceed
40kts, although low level jet and moisture return will continue
to increase ahead of the line for another couple of hours. It`s
becoming diurnally unfavorable for widespread wind damage with
the line, but these high shear/low CAPE setups often ignore this
convention. Will continue to monitor upstream evolution and
still anticipate a low end threat for some strong/severe wind
gusts with the line. These setups are also conducive for low
end/short lived spin up tornadoes along the leading edge of the
storms. So far, no tornado activity has been reported, and radar
trends are yet to show an increased threat. Will continue to
monitor for this potential with the increasing shear over the
next couple of hours.
Forecast wise, updated pops to reflect current radar evolution
and latest hi-res model trends. Limited thunder mention to
chance at this point given upstream lightning trends and the
scattered/isolated nature of the lightning activity.
Cold front will sweep moisture out of the area Sunday and then
another big surge of moisture will lift northeast across the eastern
portions of the area as the tropical system moves northeast out of
the Gulf of Mexico. QPF amounts in Akron-Canton to Youngstown could
approach 1 inch with this surge so that will have to be monitored
for heavy rain potential.
Temperatures for Sunday will be a few degrees colder today with
the cool air mass following the front. Otherwise, overnight
lows tonight will still be in the lower to middle 60s in the
warm air advection ahead of the front in most areas and then
upper 50s in the west behind the cold front. Cool air behind the
front lifts northeast of the area Sunday night allowing warmer
air to push back into the area. Looking at lows in the lower to
middle 60s once again.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Some of the models continue to track the remnants of Nate farther
west and north than the official forecast track. The forecast will
follow the NHC/WPC track and Nate should slide off to the east on
Monday. Rain will likely linger, mainly in the morning, across
northeast OH and northwest PA. Clouds may keep temps suppressed for
a while across NE OH and NW PA but the air mass will be warm. Will
forecast mid/upper 70s northwest Ohio and upper 60s to mid 70s
elsewhere.
High pressure will build across the Great Lakes Monday into Tuesday.
I suspect the high will be a bit dirty and dew points will remain
rather high. Patchy fog and perhaps some stratus could form Monday
night and Tuesday morning. Whatever clouds and fog form will likely
burn off on Tuesday and thinking that Tuesday will turn out to be a
decent day with unseasonably warm temps in the 70s.
The models are more in agreement with the timing and track of an
upper low ejecting from the southwestern states midweek. The models
still have have a variety of solutions on the strength of the
surface system. Will not go all out on the rain forecast since the
low level flow is down slope east southeast. Will forecast 30-50
percent pops by Wednesday. Even with the clouds and chance of
showers, it should remain relatively warm with highs from the mid
60s to the lower 70s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Some lingering showers in the East Wednesday night into Thursday
morning as Upper level trough begins to shift east of the forecast
area. GFS continues to be the faster of the two models with this
transition. After that surface high pressure moves across the
forecast area. The high shifts off the East Coast Saturday
allowing a low pressure system to track into the Great Lakes on
Sunday. Still doubts as the the track and timing of the low this
far out so will leave weekend forecast dry.
&&
.AVIATION /00Z Sunday THROUGH Thursday/...
Showers and thunderstorms are expected ahead of a cold front
that will push east through the terminals through the first half
of the period. A broken line of TSRA is possible, with some
brief periods of MVFR ceilings and visibility, perhaps a brief
IFR vis reduction in any stronger showers. Activity will become
more scattered east of KCLE and KMFD late in the overnight.
After 12Z, little sensible wx concerns with FEW/SCT low clouds
and increasing cirrus ahead of the next system from the south.
Winds will continue to be strong out of the south, then will
veer southwest behind the front through the overnight. Some
gusts up to 35-40 kts are possible with the line of
showers/frontal passage. Winds will decrease rapidly after
daybreak Sunday, with less than 10 kts expected through the day.
OUTLOOK...Non-VFR possible Sunday night into Wednesday.
&&
.MARINE...
Lots of changes on Lake Erie coming up in a relatively short period
of time. South winds will continue to increase this evening. Wind
speeds will spike up as a cold front crosses the lake from west to
east, roughly from 11 PM (03Z) at Maumee Bay to 5 AM (09Z) at
Buffalo Harbor. Winds will shift to southwest with frontal passage
and remain enhanced for about 6 hours or so after frontal passage.
Winds speeds will approach gale force but the large majority of the
wind is expected to stay below gale criteria. A small craft advisory
will remain in effect. A low water advisory will be issued for
western Lake Erie for the early and mid morning hours Sunday as
water levels will drop below the critical mark for navigation during
the strong southwest winds. Winds will diminish relatively quickly
Sunday late morning and afternoon as high pressure slides across the
lower Great Lakes. Water levels will recover rather quickly by late
Sunday morning.
Winds will back to south and southeast by Sunday night and then
shift to the northeast and northwest on Monday as the remnants of
Nate cross the Ohio Valley and high pressure builds across the
western Great Lakes. Winds will back to the east and southeast by
midweek as low pressure tracks across the midwest.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Low Water Advisory until 10 AM EDT Sunday for LEZ142>144-
162>164.
Small Craft Advisory until 4 PM EDT Sunday for LEZ147>149.
Small Craft Advisory until 10 AM EDT Sunday for LEZ142>146.
&&
$$
SYNOPSIS...Lombardy
NEAR TERM...Greenawalt/Lombardy
SHORT TERM...Kosarik
LONG TERM...DJB
AVIATION...Greenawalt
MARINE...Kosarik
Area Forecast Discussion
National Weather Service Green Bay WI
1056 PM CDT Sat Oct 7 2017
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Sunday
Issued at 234 PM CDT Sat Oct 7 2017
The latest RAP analysis and satellite/radar imagery show low
pressure centered over northeast Iowa, with a stationary front
extending northeast across north-central Wisconsin early this
afternoon. Periods of rain continue to lift north ahead of the
low and mid-level dry slot, which is sliding into southwestern WI.
A few thunderstorms are also popping up right ahead of the parent
shortwave over northeast Iowa, and could see some thunder moving
into parts of central WI and the far southern Fox Valley late this
afternoon into early this evening. A trailing deformation zone is
rotating around the shortwave from far western WI to central
Iowa, which is expected to arrive this evening. As the low moves
to the northeast, precip trends is the main forecast concern.
Tonight...Potent shortwave trough and associated cold front will
sweep across the area this evening before exiting around midnight.
Showers will be most widespread early this evening ahead of the
shortwave. A rain band within a skinny deformation zone will then
lift northeast across the area around mid to late evening, and
depart NE WI around 05z. Models insist on clearing skies
relatively quickly thereafter. Because of a tight pressure
gradient, winds look too mixy for a fog threat despite the heavy
rainfall. Temps falling into the mid 40s north to mid 50s south.
Sunday...Other than a moisture starved trough providing scattered
clouds over central and north-central WI, the rest of the area
should see mostly sunny skies with a breezy south wind. Temps will
be well above normal, with highs in the upper 60s to middle 70s.
.LONG TERM...Sunday Night Through Saturday
Issued at 234 PM CDT Sat Oct 7 2017
The main forecast concerns will be frost potential across northern
WI Monday night, then precipitation chances for the middle of the
week and next weekend.
A weak cold front will move through the region on Sunday night,
but little or no precipitation is anticipated due to a lack of
upper level forcing. High pressure will build into the northern
Great Lakes in the wake of the front, and linger over the region
through Tuesday. There is some potential for a frost/freeze event
over mainly northern WI Monday night/early Tuesday, but there are
concerns about whether or not clouds will decrease early enough
for a widespread event. For now, just lowered temperatures a few
degrees in the typical cold spots and added patchy/areas of frost
in north central and far northeast WI between 09z-14z/Tues.
An upper level trof and associated surface low will impact the
region Tuesday night into Wednesday. Th ECMWF is stronger and
farther north, and would bring a steady light to moderate rain to
most of the forecast area, while the GFS is weaker and farther
south, and just brings scattered showers to our southeast
counties. Will stick with the model blend for now and make
adjustments over upcoming days.
A fairly potent frontal system is possible next Friday night and
Saturday. Models show an 850 mb warm front lifting north through
the region, with a strong low-level jet developing on Saturday.
In addition, the RRQ of a 150 knot jet would provide upper
support. Elevated instability is expected to arrive on Saturday,
so added a mention of thunder in the forecast.
A cooling trend is expected early next week with mainly northerly
surface flow, but moderating temperatures should return later in
the week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1056 PM CDT Sat Oct 7 2017
Isolated showers and MVFR cigs will shift eastward overnight as a
low pressure system lifts northeastward and a cold front tracks
east of the state. MVFR cigs will improve to VFR levels, however
clearing skies and light winds with the recent rainfall may lead
to areas of mvfr/ifr fog later tonight. VFR conditions are then
expected for Sunday.
&&
.MARINE...
Issued at 234 PM CDT Sat Oct 7 2017
Gale force gusts have yet to materialize over the central Bay and
northern Lake Michigan so far today. With winds expected to
gradually decrease for the rest of the afternoon, will downgrade
the gale warning to a small craft advisory.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......TDH
MARINE.........MPC
Area Forecast Discussion
National Weather Service Indianapolis IN
1139 PM EDT Sat Oct 7 2017
.UPDATE...
The Aviation section has been updated below.
&&
.SYNOPSIS...
Issued at 1236 PM EDT Sat Oct 7 2017
A cold front will sweep across Central Indiana this
evening...bringing showers and isolated thunderstorms to the area.
Dry weather will briefly resume late tonight as the front departs
overnight and on Sunday morning. However by Sunday afternoon and
Sunday night...moisture associated with Hurricane Nate will begin
to surge into the Ohio Valley. This will result in rain chances
returning to mainly southeast parts of Central Indiana late Sunday
afternoon and Sunday night.
As the hurricane Remnants depart on Monday...Dry weather will once
again return as High pressure strengthens over the upper midwest
and provides dry northerly flow to Indiana.
Rain chances will then return on Tuesday night and Wednesday as a
warm front approaches and an associated Low pressure system pushes
toward the Tennessee River Valley.
&&
.NEAR TERM /Tonight/...
Issued at 650 PM EDT Sat Oct 7 2017
Minor adjustments to pops to better reflect current radar trends.
Expect line of heavy rain and a few rumbles of thunder to sweep
across the forecast area in the next couple of hours and depart
relatively quickly. Threat remains for isolated damaging wind
gusts and perhaps even a quick spinup. All areas will likely see
at least a period of heavy rainfall and quick wind gusts to 40-45
MPH with the line. Previous discussion follows.
Issued at 1236 PM EDT Sat Oct 7 2017
Surface analysis early this afternoon shows a cold front
stretching pushing toward eastern Missouri. The front was
associated with Low pressure which was found over Iowa and
Wisconsin. GOES16 shows a cloud shield ahead of the front across
Illinois and Missouri. Radar shows an area of showers over Western
Illinois.
HRRR continues to suggest the eastward progression of the cold
front and associate showers tonight...reaching the
Illinois/Indiana state line near 23Z before progressing across the
state through 04Z. Time Heights how good lower level moisture and
strong lift as this front is expected to pass. Forecast soundings
also show limited instability with marginal CAPE of around 400
J/KG...but some good moisture within the lower levels. Convective
temps are suggested to be in the upper 70s. Thus some limited
shallow development is expected late this afternoon ahead of the
front. Will try and raise pops late this afternoon and early
evening with the expected FROPA. Given the strong drying and
subsidence that is seen within the wake of the
front....will quickly trend toward a dry forecast after
06Z...sticking close to the blend on Temps.
&&
.SHORT TERM /Sunday through Tuesday/...
Issued at 1236 PM EDT Sat Oct 7 2017
Large High pressure aloft off the Carolina coast will continue to
allow for a warm and moist flow of gulf air into the Ohio Valley.
The remnants of Hurricane Nate look to follow this path through
the deep south late tonight and into the Ohio and Tennessee
valleys on Sunday. Models suggest excellent moisture arriving
across southeast parts of the forecast area...while a sharp cut-
off will exist to the northwest. Forecast soundings across IND
fail to show deep saturation...but much better saturation appears
present to the southeast. Thus given this path...will trend highs
pops on Saturday afternoon and evening...mainly across the
southeast parts of the forecast area with a sharp decrease in pops
to the northwest. Again will use a blend on Temps.
By Monday morning...the GFS suggests that remnants of Nate will
have reached West Virginia and will be quickly moving northeast.
Meanwhile strong ridging begins to settle across the Western Great
Lakes...allowing for Northerly flow to central Indiana. Forecast
soundings respond with a very dry column...and convective
temperatures that appear reachable. Aloft...southwest flow remains
prevalent on Monday and Tuesday...as a deeper upper low begins to
push in to the western plains states. Little in the way of
dynamics appear to surge ahead of the low...which should help to
keep Indiana dry on Monday and Tuesday. The quick albeit moist
flow aloft may result in mainly just some High cloud. Forecast
builder may try into introduce some pops on late Tuesday as the
GFS hints at a warm front approaching from the southwest ahead of
Low pressure...but for now...this looks more likely to arrive on
Tuesday Night and Wednesday.
&&
.LONG TERM /Tuesday night through Saturday/...
Issued at 207 PM EDT Sat Oct 7 2017
The long term period will begin with an active weather pattern in
place as an upper wave and associated surface front move through
central Indiana. This will keep chances for showers in the forecast
through Wednesday. By Wednesday night though models agree that upper
ridging will start to build over the area. Thus after cooling to
near normal for Wednesday and Thursday in the wake of a cold frontal
passage, warming will return Friday under building surface high
pressure.
&&
.AVIATION /Discussion for the 08/06Z TAFs/...
Issued at 1140 PM EDT Sat Oct 7 2017
VFR initially may give way to MVFR for a time near daybreak.
With skies clearing and wet ground, expect some fog to develop
near daybreak. Will carry 2 miles at the outlying sites and 3
miles at IND, with a BCFG mention as patchy dense cannot be ruled
out. Will have to monitor this overnight as winds die down.
Winds will generally be below 10KT throughout the period, westerly
early and occasionally variable later in the period, before
becoming more easterly.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...Puma
NEAR TERM...Puma/Nield
SHORT TERM...Puma
LONG TERM...CP
AVIATION...Nield
Area Forecast Discussion
National Weather Service Jacksonville FL
858 PM EDT Sat Oct 7 2017
.UPDATE...
The convection near and west of I-75 is actually some sea breeze
convergence but has become somewhat entrained in the very, very,
very outer periphery of Nate`s circulation. Thus it has just a
little bit more than normal diurnal heating support and will go on
until midnight or 1 a.m.
After that will see some mid deck and the high cirrus/cirrostratus
outflow from the tropical system overnight. Also will see a weak
southeasterly flow around the system keeping winds in the 4 to 8
mph range. Both of those factors should serve to limit fog
formation but still might see some light mist near sunrise at the
usual places such as Cecil Airport and Gainesville.
&&
.AVIATION...
Convection is moving past Gainesville Regional Airport now and the
band of convection is expected to fall apart before it can reach
the Jacksonville Metro fields. Might see some light mist near
Gainesville and Cecil Airport Sunday morning and will keep in the
5-6sm range. Should see some convection tomorrow afternoon as Nate
passes to our north and west and outer rainbands trail across the
region. Will go with cloud bases at 5 KFT for now but later shifts
may have to lower bases is more tropical based convection becomes
evident. Convection should begin between 17-19 utc based on the
NAm12 and HRRR solutions.
&&
.MARINE...SCEC for seas will remain intact for the offshore waters
for tonight. SCEC will likely be needed on Sunday due to stronger
southerly flow near 15-20 kt. Seas may continue to be dominates by
swells of about 9-10 seconds. An extended period of onshore flow
will continue Mon with winds near 10-15 kt or less...with lighter
winds by mid week.
Rip Currents: Moderate risk of life threatening rip currents on
Sunday as the southeasterly flow increases.
&&
.HYDROLOGY/COASTAL FLOODING...Minor to moderate coastal flooding
anticipated in the St. Johns River Basin into Monday Morning.
Water levels about 1.5 to near 2 ft above astronomical predictions
with moderate flooding occurring near the time of high tide. This
is a combination of Fresh water flooding on top of the normal
river brackish layer and the "King Tides" peaking on Monday and
Tuesday.
Trends continue to
show a downward trend in water levels. Sante Fe River basin
remains in minor flood.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 90 76 86 75 / 30 30 80 30
SSI 83 77 85 77 / 20 20 50 20
JAX 90 77 88 75 / 20 20 60 30
SGJ 86 77 88 75 / 20 20 40 20
GNV 89 76 88 73 / 50 40 70 30
OCF 89 76 89 73 / 60 50 80 30
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Warning until 6 AM EDT Monday for Clay-Coastal
Duval-Flagler-Inland Duval-Putnam-St. Johns.
GA...None.
AM...None.
&&
$$
Hess/Sandrik/Corless
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
621 PM CDT Sat Oct 7 2017
.SYNOPSIS...
Issued at 325 PM CDT Sat Oct 7 2017
H5 analysis from earlier this morning had a strong trough of low
pressure centered over central Kansas. Ht falls in association
with this feature, were most pronounced across southern Kansas
into western Missouri. Downstream of this feature, high pressure
was anchored off the coast of the Carolinas with a ridge extending
north into Quebec. West of the central CONUS trough, a low
amplitude ridge was present from California north into southern
Idaho. A trough was present north of the ridge across the Canadian
prairie provinces with some 150 to 200 meter ht falls noted over
Saskatchewan into western Manitoba. At the surface, low pressure
was anchored over central Iowa with a cold front extending south
into the Ozarks. West of this feature, clearing skies and westerly
winds were present across western and north central Nebraska.
Readings as of 1 PM CDT ranged from 65 at O`Neill to 75 at
Valentine.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 325 PM CDT Sat Oct 7 2017
This evening and tonight... Available moisture remains minimal ahead
of the cold front approaching the panhandle. Dew point depressions
range from 25F at KONL to 35F at KIML as of 20z and PWATs under 0.5
inch according to RAP mesoanalysis. Models are consistent with
overall subsidence and isentropic downglide through 12z Sunday, and
little cloudiness is shown upstream in WV/IR imagery, suggesting a
generally clear night for western Neb. Made little change to min
temps, keeping upper 30s far NW and lower/mid 40s elsewhere, which
is above guidance. An H85 thermal ridge with temps as warm as 20C
crosses the forecast area overnight. Along with a 30+ kt LLJ, some
of which may translate to the sfc, winds should stay somewhat
elevated and limit decoupling/cooling.
Sunday... The cold front should be east of the forecast area by 12z
and with continued limited moisture, expecting a dry fropa. CAA is
well underway at 18z with H85 temps falling back below 10C. Forcing
and moisture advection strengthen during the afternoon as a lee side
low develops in SE CO/SW KS and a shortwave exits CO/WY. Saturation
will be rather slow across the area and have held off PoP for all
areas except NW Sheridan Co. after 21z. Went with general blend for
max temps, averaging the warmer MET and MAV with the cooler ECS,
resulting in upper 50s NW to near 70 far SW.
.LONG TERM...(Sunday night through Saturday)
Issued at 325 PM CDT Sat Oct 7 2017
Sunday night through Tuesday: Precipitation chances Sunday
night/Monday followed by the potential for freezing conditions
Tuesday morning are the main forecast concerns in the mid range.
Beginning Sunday night, a potent H5 shortwave will dive south into
northern Utah. As this feature tracks southeast into western
Colorado overnight, mid level frontogenesis will increase from
southern Wyoming into the Nebraska Panhandle and northwestern
Nebraska. Cross sections taken from south central into
northwestern Nebraska indicate a nice area of mid level lift
across the western and northwestern sandhills overnight, with
plenty of mid to low level moisture present. This lift resides in
the saturated dendritic zone, so favorable conditions exist for
snowfall in the nwrn cwa overnight. One thing which will limit
accumulations though is the very warm ground temps and temps in
the 33 to 35 degree range. The latest soil temps from UNL Crop
Watch indicate soil temps in the northwestern CWA well into the
upper 50s. The warm ground temps will limit snow accums during the
night and combination of sun and warm ground temps will almost
eliminate any threat for snow accums during the daylight hours
Monday. That being said, will limit snow accums to the
northwestern forecast area Sunday night and keep them on the order
of an inch or less which is in agreement with the latest WPC
depiction. For Monday, the GFS and NAM12 solns, drop the H5 low
into southern Colorado. Favorable mid level frontogenesis will
transition south into swrn Nebraska, as well as central portions
of the forecast area, before shifting east Monday night. As the
mid level fronto band shifts south, any threat for snow will end
by mid morning due to a combination of temps in the upper
30s/lower 40s and warm ground conditions. By Monday evening, there
are some differences between the GFS and NAM12 solution with
respect to the H5 low. The NAM12 soln closes the low off over
southern Kansas Monday night while the GFS lifts this feature east
across Kansas as an open wave. The more progressive GFS soln
would equate to drier conds Monday night, while the slower NAM12
soln would allow pcpn to linger in the east Monday night. The
inherited forecast does linger pops in the eastern CWA Monday
night and will leave as is for now. Further west, dry air will
filter in behind the exiting system with dew points falling off
into the teens and lower 20s. The combination of dry air, high
pressure and a cold airmass behind the front, will lead to
widespread lows in the 20s with readings around 30 in the east.
Inherited forecast has widespread frost across the forecast area
and will probably need to issue a freeze warning for most of the
forecast area sometime Sunday night or Monday, for Monday night.
Will continue to hit this in the HWO.
Tuesday night through Saturday: In the wake of the exiting system
early next week, a low amplitude ridge will push into the northern
Rockies and northern plains midweek. Warmer air will push into the
central plains from the swrn CONUS which will push highs back into
60s Wednesday through Friday. Late Thursday, a shortwave trough of
low pressure will traverse southern Canada, forcing a weak cold
front into the region Thursday night. Its impacts will be greatest
on the northern and northwestern forecast area, where highs will be
around 60 for Friday. On Saturday, a second, deeper trough of low
pressure will track from the nwrn CONUS into northern California.
This will amplify a downstream ridge across the Ohio valley and
southern plains. Further north, swrly flow aloft will become
anchored across the central plains. This will lead to warmer temps
and a threat for showers and thunderstorms across southern and
eastern Nebraska.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 621 PM CDT Sat Oct 7 2017
VFR is expected all areas overnight and Sunday.
A Pacific cold front, currently across MT, will move through
overnight. No significant low level cloudiness is indicated in
any of the models. Scattered midlevel clouds will prevail.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Snively
LONG TERM...Buttler
AVIATION...CDC
Area Forecast Discussion
National Weather Service Marquette MI
700 PM EDT Sat Oct 7 2017
.SHORT TERM...(This evening through Sunday)
Issued at 410 PM EDT SAT OCT 7 2017
WV imagery and RAP analysis indicated a vigorous mid/upper level
shortwave trough lifting northeast into srn WI. At the surface, an
elongated 993 mb low extended from wrn Upper Michigan into se MN
resulting breezy southwest winds over the east half of the cwa with
gusts to 30 knots at KERY. Although the larger area of heavy rain
supported by the stronger upper level div from the the jet right
entrance and 850-600 fgen has lifted to the northeast of the cwa, a
trailing band of 850-600 mb deformation/fgen and narrow band of shra
was aligning/moving toward central Upper Michigan.
Tonight, short range models suggest the narrow band of heavier pcpn
will affect areas of w cntrl Upper Michigan mainly west of Marquette
into the early evening before sliding to the east btwn 00z-03z.
However, some sct -shra will still linger over the rest of the
cwa. By late evening and overnight the pcpn will quickly exit to
the east and end with clearing quickly spreading over the area.
Sunday, Sunshine and mixing with 900 mb temps around 15C will
support max readings into the lower 70s, especially where downslope
wsw flow prevails.
.LONG TERM...(Sunday night through Saturday)
Issued at 308 PM EDT SAT OCT 7 2017
Overall, the weather looks to remain rather quiet next week, with
periodic chances for showers towards the end of the week/early next
weekend. Temperatures will fluctuate through the week as we start off
seasonal and then warm up into the low to mid 60s by the middle of
the week, and then back to more seasonal early next weekend.
Monday through Tuesday, the weather is expected to remain quiet as
high pressure drops down from Canada. There is an upper-level trough
progged to move across the Upper Great Lakes; however, with a much
drier airmass advecting across the area do not expect any
precipitation to reach the ground.
Wednesday through Friday, surface ridging will move east of the area
with high pressure reaching the East Coast by Thursday/Friday. This
will allow return flow developing across the Central and Upper
Mississippi Valleys to move across Upper Michigan ahead of
approaching longwave troughing over the western CONUS. 850mb
temperatures will warm to near or around 10C towards the end of the
week as a result, allowing for the return of above normal
temperatures. This return of warmer air and increasing moisture will
also allow for periodic chances for showers later in the week as a
weakening cold front tracks across the area. Medium range models
show a lead shortwave ejecting out of the aforementioned longwave
troughing across the Upper Mississippi Valley, with the main surface
low remaining well north of the area in Canada. With the better lift
tracking north of Upper Michigan do not expect widespread
precipitation associated with the frontal passage at this time.
Next weekend, as the above mentioned longwave troughing slowly
continues to traverse the Rockies and moves out across the Plains,
the medium range models diverge in the strength of this trough.
Therefore, confidence is not high in regards to how precipitation
chances will play out as the track and timing of the system
associated with this upper-level energy remains rather variable.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 700 PM EDT SAT OCT 7 2017
Conditions will improve quickly at all sites tonight as the showers
moves out. Improvement to VFR should occur at KIWD/KCMX this evening
and at KSAW by 06z.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 410 PM EDT SAT OCT 7 2017
Broad sfc low will track ne across the e half of Lake Superior this
evening with gusty ssw winds to near 30 knots over the far ern
portion of the lake. Winds will be much lighter to the w of the low
track over western Lake Superior. As the low departs tonight, w to
sw winds of 20-30kt will develop across most of the lake. Winds will
diminish on Sun, and winds should be mostly less than 20kt Sunday
night thru Thu.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
Gale Warning until 8 PM EDT this evening for LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...Ritzman
AVIATION...07
MARINE...JLB