Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/25/18
Area Forecast Discussion
National Weather Service Bismarck ND
957 PM CDT Sat Mar 24 2018
.UPDATE...
Issued at 952 PM CDT Sat Mar 24 2018
Current forecast trending ok with local and regional radars showing
a plume of reflectivity across southwest North Dakota. The 00Z NAM
compares favorably to this so will leave forecast unchanged.
UPDATE Issued at 708 PM CDT Sat Mar 24 2018
Latest satellite and radar images suggest some light precipitation
is newly forming across southwest North Dakota. Will re-arrange
the POPs to reflect this apparent initiation and leave the
northwest dryer for a while.
So the plan is for light rain to develop across the southwest
first and spread northeast this evening, becoming mixed with
freezing rain late this evening south central, and turning to snow
overnight central and east while ending west.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 309 PM CDT Sat Mar 24 2018
The western longwave trough that has been keeping our region in an
active weather pattern will eject another shortwave towards
western North Dakota. One mid level vort max will skirt the
northwest, and temperature profiles via BUFKIT suggest a wintry
mix of freezing drizzle, rain, and snow this evening before moving
into the Turtle Mountains overnight
Another vort max will organize over central South Dakota and move
into the James River Valley by early Sunday morning, which will
also bring chances of a wintry mix. The 12z NAM did show a brief
period of freezing rain possible with a warm nose aloft and a
saturated surface layer, but dry air in the 700-500mb layer should
help to cool the warm nose fairly quickly as ice crystals begin to
fall from the near saturated layer above, resulting in mainly
snow. Parts of the southern James River Valley can expect 2 to 3
inches with totals generally under an inch elsewhere. Light
freezing rain or freezing drizzle will potentially linger on the
backside of the snow, as far west as the Bismarck area.
On a final side note: there is a non-zero chance for
thunderstorms across the northwest and central part of the state
tonight with the initial vort max that crosses into the
northwest. The HRRR iterations have been consistent showing
elevated vertical velocity signals and lightning probabilities co-
located with resolved convection. With such little confidence in
this solution, decided to keep it out of the official forecast,
but we will be watching closely to see how it evolves.
.LONG TERM...(Sunday night through Saturday)
Issued at 309 PM CDT Sat Mar 24 2018
As the shortwave exits the area Sunday night, the western trough
ejects another one right on its heals. At this time, most of the
precipitation will remain in South Dakota, but some light snowfall
accumulations are likely to impact our southern tier of counties
through Monday.
By Tuesday, an upper level ridge will become the dominant feature
over the western CONUS, putting the region back into northwest
flow aloft. Various hit or miss Clipper systems will bring periods
of light snow to our area through the week, but as the model
solutions are very different, certainty in timing and location of
these features are low.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 708 PM CDT Sat Mar 24 2018
Hazards to aviation include MVFR, IFR and freezing drizzle and
snow. Widespread MVFR conditions will prevail Saturday evening,
Becoming IFR in freezing drizzle KBIS-KMOT 06-10Z and snow KBIS-
KJMS after 10Z. Conditions becoming VFR KISN-KDIK after 12z and
KBIS after 18Z.
&&
.HYDROLOGY...
Issued at 309 PM CDT Sat Mar 24 2018
Upstream river observations along the Yellowstone River in
southeastern Montana indicate ice is pushing water up and over the
banks, from Savage to near Sidney. This high water will continue
to work into far northwestern McKenzie County of North Dakota,
near East Fairview and Cartwright between midnight and 6 AM CDT
Sunday. Thereafter, high water is expected to reach the Missouri
River near Williston by early Sunday afternoon, with water levels
reaching minor flood stage. The high water is mostly due to ice
restrictions in the river. Once the ice has passed, water levels
will quickly fall below minor flood stage, which is forecast to
occur Monday morning.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...WAA
HYDROLOGY...KS
Area Forecast Discussion
National Weather Service Denver/Boulder CO
900 PM MDT Sat Mar 24 2018
.UPDATE...
Issued at 900 PM MDT Sat Mar 24 2018
Just a few light showers passing over northern Jefferson and
southern Boulder counties pushing east into Weld County. Just a
few light rain drops expected. These should end in the next hour
or two as drying on satellite is visible to move over the area.
Gusty southerly winds are taking their time to decrease, should
see a more drastic difference after 10pm.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 212 PM MDT Sat Mar 24 2018
Southwest flow aloft will prevail tonight and Sunday ahead of an
upper level trough over the Pacific Northwest and Great Basin.
High clouds over Colorado extend southwest across the Desert
Southwest. They will continue to stream over the region through
tonight and into Sunday. Some models are showing precipitation
over the mountains this afternoon and evening. This is due to a
few convective showers. So far cumulus clouds are having a hard
time forming. Will keep the mention of showers out of the forecast
for tonight except for far north central Colorado.
A surface low will deepen over southeast Colorado Sunday. This
will bring increasing east to southeast winds to the eastern
plains. This will increase low level moisture through the day. A
few showers and thunderstorms may form late in the afternoon as
the airmass becomes unstable. Better chance for precipitation
looks to be in the evening hours. Highs Sunday will mild and in
the 60s for most of northeast Colorado. The far northeast corner
may stay under low clouds for most of the day and stay in the 50s.
.LONG TERM...(Sunday night through Saturday)
Issued at 212 PM MDT Sat Mar 24 2018
Sunday night, weak mid level qg ascent will be over the cwa ahead
of the upper trough axis along the eastern ID/western WY line by
06z Monday, it then lifts north and east of the region by 12z
Monday. At the sfc, an area of low pressure will be over southeast
CO with an inverted trough extending northward. This will result
in a weak east/northeasterly surge coupled with weak forcing
aloft that could produce isolated to scattered showers Monday
evening, following by areas of stratus and lingering drizzle
overnight. The best chance of showers will be along the northern
border. Monday and Monday night, weak mid level qg ascent will
increase from the southwest, ahead of the southern branch of the
trough located in the Great Basin region 00z Tuesday. In addition,
a cold front will push into the cwa from the north/northeast
upslope from the surface to around 700 mb through Monday evening
then weakening overnight. The qg ascent associated with the trough
shifts south overnight with the trough, which will allow the pcpn
over the cwa to taper off as well. Greatest qpf occur in the
evening period, then lighter qpf lingering over the southern part
of the cwa late Monday night and Tuesday morning. At this time,
models generating advisory type snowfall in zones 34, 36 and 41
with potential amounts in the 4-10 inch range there. Tuesday and
Tuesday night, there will be a weak deformation zone over the
region through midday, then a cool and drier northwesterly flow
kicks as the trough exits east and mid level subsidence/qg
descent occurs Tuesday afternoon and Tuesday night. The next
transition will occur late Wednesday and Wednesday night. An upper
trough is progged to drop out of the northern Rockies with
increasing qg ascent from north to south around 00z Thu. A cold
front, following by upslope and weak mid level qg ascent is still
progged for Wednesday night. Enhanced bands of pcpn, mainly snow,
could also be part of the equation at that time with a passage of
an upper level jet. This system still appears to exit the region
by midday Thu, allowing for a dry northwesterly flow to occur late
Thursday into the weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 900 PM MDT Sat Mar 24 2018
Winds will remain a south to southeast direction through tonight.
Wind gusts to 25 knots will be possible through 04-05Z. Low
clouds will enter eastern Colorado tonight with ceilings under
1000 feet. At this time, it still appears that these low clouds
will stay east of the Denver area. However, there is a small
chance they reach KDEN for a short time. The latest HRRR shows a
bit of a cyclone that may turn winds northwesterly after 12z for a
few hours, but only showing vis reduced to 6sm from 12sm
previously. Will keep any mention of vis reductions out of TAFs.
May see some shower activity Sunday late afternoon into early
evening, mainly near DEN or BJC, with stratus likely pushing in by
midnight Sunday night.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Kriederman
SHORT TERM...Meier
LONG TERM...Cooper
AVIATION...Meier
Area Forecast Discussion
National Weather Service Dodge City KS
600 PM CDT Sat Mar 24 2018
...Updated Aviation...
.SHORT TERM...(This evening through Sunday)
Issued at 344 PM CDT Sat Mar 24 2018
Water vapor loop and RAP analysis this afternoon showed a fairly
impressive, small-scale storm across Iowa with sharp shortwave
ridging in its wake across the Central Plains. A much larger scale
trough was forming along the West Coast, and the increased southwest
flow aloft ahead of this trough was allowing high level Pacific
moisture to push into the Desert Southwest and Rockies. Some of this
high cloud was starting to push into eastern Colorado this
afternoon. In the lower levels, the edge of stratus cloud was quasi-
stationary from near LBF to RSL to near ICT. A narrow ridge of
surface high pressure was centered from central Nebraska into
western Kansas. The shallow cool airmass across Nebraska will expand
southwest tonight thanks to nocturnal pressure rises, but at the
same time, a leeside trough will start to strengthen over eastern
Colorado. Surface winds will gradually veer to the southeast, and is
happening a bit slower than previous short term model runs were
indicating, which is not really a surprise.
The upshot of all this is that this cool airmass across western
Kansas tomorrow morning will be very difficult to dislodge from
southwest to northeast thanks to isentropic lift off the surface
leading to widespread stratus. Patchy drizzle will also be likely
across mainly west central KS where this saturated low level airmass
will be a little deeper with decent warm advection in the 900-800mb
layer. As far as temperatures go, this will be a huge forecast
challenge, given the fact that areas farther north toward I-70
should stay socked in with low stratus and patchy drizzle much of
the day. Farther southwest, toward Elkhart, southwest downslope
momentum will develop and temperatures should respond very nicely.
We will probably be looking at close to 30-degree (F) gradient
across western KS from Elkhart to Hays or points just north. The
official forecast for temperatures is largely a blend of the latest
mesoscale models with some added weight toward the NAM solutions,
which are colder (although probably a touch too cool).
.LONG TERM...(Sunday night through Saturday)
Issued at 344 PM CDT Sat Mar 24 2018
The deep western trough that was mentioned in the Short Term section
will push out across the Rockies and Desert Southwest region Monday-
Tuesday, but will be taking on a positively-tilted orientation,
which does not bode well for significant precipitation across
western Kansas. In fact, much of the southwest KS will probably
stay dry through this trough passage early-mid week. Tuesday will
be fairly cool with fresh Canadian airmass pushing in, although
not overly cold. We will likely see highs in the lower 50s much of
the area Tuesday, with a recovery to the 60s Wednesday. A
secondary jet streak on the back side of the longwave trough will
push into Wyoming and Colorado Wednesday Night-Thursday, and this
will likely lead to another shot of low level cold advection and
possibly some scattered showers given how cold aloft it will
likely be. This deep trough axis will finally shift east by
Friday, leading to a renewed warmup period going into the next
weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 600 PM CDT Sat Mar 24 2018
High confidence that stratus will spread into the SW KS terminals
tonight through Sunday morning. IFR cigs are expected. SE winds
will remain elevated tonight, assisting with strong moisture
advection. Kept surface visibility largely unrestricted in the
TAFs, but areas of BR/DZ are expected during the 09z-18z Sun
timeframe. Stratus will gradually erode from west to east during
the daylight hours on Sunday, but stratus will persist much of the
day at HYS. Surface pressure gradient will tighten after 15z Sun,
as a 996 mb surface cyclone develops in SE Colorado. Strong SE
winds will result at GCK/DDC, averaging 20-30 kts. Expect SE winds
to be slightly less at HYS, and trend southerly at LBL Sunday
afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 39 64 46 68 / 10 20 20 10
GCK 40 69 41 67 / 0 10 20 10
EHA 42 79 43 70 / 0 0 0 0
LBL 44 78 44 71 / 0 0 10 0
HYS 34 50 43 63 / 10 20 50 20
P28 40 60 51 74 / 10 20 40 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Turner
Area Forecast Discussion
National Weather Service Green Bay WI
1035 PM CDT Sat Mar 24 2018
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Sunday
Issued at 241 PM CDT Sat Mar 24 2018
The latest RAP analysis and satellite/radar imagery show high
pressure stretching from James Bay into the northern Great Lakes
early this afternoon. Meanwhile, a band of precipitation is
extending from northern Iowa into the southern Appalachians.
Central and northern WI remains on the northern edge of this storm
system, with broken cirrus extending across northern WI. The
clouds in combo with east winds have cooled temps several degrees
from yesterday. As high pressure continues to be the main
influence of the weather across the region, temps and low
humidities remain the main forecast concerns.
Tonight...The storm system will continue to track southeast across
the Ohio Valley. As a result, will see the blanket of high clouds
gradually thin out during the evening, then skies will become mostly
clear overnight. But even with clearing skies and a dry airmass
in place, do not think temps will tank in the northwoods due to
persistent 5 kts of east flow. Lows ranging from around 10 above
in Vilas county to the mid 20s near Lake Michigan.
Sunday...Should see temps moderate some as the surface high moves
further east of the region and with more sunshine. Mixing should
tap into very dry air aloft, leading to widespread low dew
points, some as low as zero in north central WI. This will lead to
very low relative humidity in the 15 to 25 percent range in the
sandy soil regions. The combination of low humidity and breezy
east to southeast winds will result in elevated fire weather
conditions, especially in the grassy areas of central and east
central WI, where there is little or no snow cover. Warmer highs
ranging from the mid 30s near Lake Michigan to the middle 40s over
central WI.
.LONG TERM...Sunday Night Through Saturday
Issued at 241 PM CDT Sat Mar 24 2018
Boundary layer high pressure will drift eastward Sunday night
into Monday morning for continued dry conditions. Southwest flow
aloft develops Monday as the upper ridge shifts east to start a
brief pattern change.
Clouds and then the chance of rain will be on the increase from
west to east Monday afternoon into Monday evening as return flow
and develops ahead of the next low pressure system. Best forcing
arrives later Monday night as the southerly LLJ works into the
area. Will keep pcpn type all rain due to a warm start Monday
afternoon, but a few locations across the north may have a brief
snow mix due to evap cooling effects from the departing dry air
mass. Best combination of forcing and pwats 0.75 to 1.00 inches
arrives late Monday night into Tuesday. Isold storms possible
late Monday night into mid day Tuesday as total totals climb to
the 45 to 50 range. ECMWF is a bit quicker with the departure
east with the precipitation later Tuesday afternoon due to a
trough system. The GFS is slower but has shifted from a closed
low system to trough as well Tuesday.
Cold northwest flow returns for the remainder of next week with
several chances of a mixed precipitation. Confidence with timing
and strength of these systems remains low.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1032 PM CDT Sat Mar 24 2018
Good flight conditions are expected the next 24 hours. Winds over
east-central Wisconsin have decreased since late afternoon.
Decoupling will probably limit gustiness overnight, though it may
return on Sunday. But winds won`t be as strong as Saturday. Dry
air at low and middle-levels will limit clouds to just cirrus.
&&
.HYDROLOGY...
Issued at 241 PM CDT Sat Mar 24 2018
With the exception of shaded forested areas south of highway 8,
only snow cover left across the forecast area is mainly over
areas northward. Even that snow cover has likely been worked over
some the last few days due to the sublimation process with the
dry Hudson Bay east flow. For snow less areas, continued cold
overnight low temperatures and a lack of a penetrating rain, has
allowed a healthy frost to remain several inches below a thawed
surface layer. A system tracking over the northern Great Lakes
region Monday night into Tuesday continues to indicate a
widespread nearly half inch of rainfall. This rainfall will make
a good attempt to knock the frost out, but run off will be above
normal for this amount of rain resulting in some small streams
and creeks rising. Across the north, above freezing overnight
lows Monday night along with the rain will reduce the snow cover.
River flooding issues should be minimal with these conditions, but
will be monitored. Thunderstorms are possible across parts of
East Central Wisconsin, so rain amounts may be locally higher but
confidence is low at this time for storms.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......Skowronski
HYDROLOGY......TDH
Area Forecast Discussion
National Weather Service Gray ME
1025 PM EDT Sat Mar 24 2018
.SYNOPSIS...
An upper trough of low pressure will drop south through Western
New England and into southern New England overnight. High
pressure will build over the region Sunday afternoon and into
Tuesday. An upper trough will slowly approach from the west
Wednesday and move across the region Thursday into Friday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1020 PM...BEst looking snow showers, on radar, are moving thru
parts of the area attm, so threat quick coating or so snow will
likely occur in the hour two if your going to get it. Best
cluster runs from NE of KAUG, through nrn Andro county and on
up toward Mt Blue. This should cross the srn half of Oxford and
the the Bridgton-Naples areas of Cumberland before midnight,
and could produce a quick inch of snow. Not sure it will hold
together into NH Lakes Region, but it will move there around or
shortly after midnight. The snow showers should continue to
weaken as they move SW into srn NH later tonight.
710 PM...Scattered rain and snow showers continue to track SW
across Me and into NH, except for the CT vly region, where it is
dry. These are associate with some instability associated with
500 MB trough diving die south and sort of neg tilting, relative
to its own motion, but neccesarily in the way we always look at
it. It will also bring a backdoor cold front across the region
later tonight. The precip is somewhat driven by sfc based
instability, so that forcing should wane this evening. The HRRR
shows a flare up in the precip through about 02-03Z, although it
will remain showery in nature, Although showers should become
more snow than rain as the evening wears on. So Can`t rule out a
coasting of snow this evening in some spots, but this will be
more likely are unpaved surfaces. One other thing worth noting,
is that temps will begin to drop below freezing in many spots
around and after midnight, so some icy spots could develop where
there are wet roads.
With this in mind, I have gone more with scattered showers thru
about midnight across most of the CWA, but lingering into the
pre-dawn far srn zones. I also back off QPF and subsequent snow
amount with less than an inch across most of the foothills and
coastal plain, with some 1-2" amts possible in the mtns.
Previously...A vigorous upper trof will dig south to southeast
through upstate New York tonight and then to the mid Atlantic
area by morning. This upper trof is vigorous but moisture
starved so only scattered snow showers are expected with this
system with maybe a more widespread light snow in the mountains.
In the mountains and foothills an inch or two may occur. Even
with mid afternoon temps in the lower to mid 40s snow showers
are noted due to the very cold temps aloft so will not mention
any liquid PTYPE going forward in afternoon package. Its
interesting how aggressive GFS model is with QPF but need to
disregard since very dry air and associated low dewpoints will
drain south on the north to northeast winds. Most areas should
remain around a dusting to less than an inch except in the
mountains.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
The upper trof will continue to dig southeast Sunday allowing
drier Canadian high pres to build from the north allowing skies
to clear in the afternoon. The ridge of high pres will amplify
and build across the region Sunday night allowing clear skies
and light winds so radiational cooling will make for a cold
night with lows dropping into the single teens to lower 20s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
High pressure builds over the area with a ridge aloft sliding in
from the northwest. This spells dry weather, calm winds, and
gradually warming temperatures at least through Tuesday. With
high pressure over the region, nighttime temperatures will drop
easily in good radiational cooling conditions.
In the mid to late week period we will see a series of shortwave
troughs rotating around a larger upper trough in central North
America. Each one of these troughs pushes back a bit more on the
upper ridge over the Northeast. Models are not in great
agreement on the details of when and how each one of these waves
will evolve and affect our region, but the overall concept is
consistent that the ridge will break down after being chipped
away at by each of these troughs.
The first wave is generally agreed to arrive on Wednesday, with
the majority of its energy moving by to our north. A cold front
tries to push into our area, but as it loses its forcing it
will lose its identity as it arrives. Thus expect the warmer
conditions to last until at least Thursday. The next wave
arrives on Friday or Friday night and tracks closer to our area.
Whether it tracks a little to the west bringing warmer
conditions and rain, or a little to the east bringing a better
chance of snow, is still in question. Notably the GFS has,
probably unreasonably, lost the Friday system by taking it into
the Atlantic over the Carolinas and harmlessly out to sea. But
the CMC and ECMWF models have gone from showing two separate
waves in the Friday-Saturday period to just one stronger one,
tracking toward our area. So expect an increased chance of
precipitation in this time period with rain or snow possible
depending on the track. Unfortunately that`s really the most
detailed we have confidence in being at this point considering
the variety of possibilities and lack of consistency in our
forecast models.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Short Term...MVFR/IFR ceilings and vsbys in areas of snow
showers tonight....then VFR except for some areas of MVFR
ceilings early Sunday.
Long Term... VFR conditions through Tuesday with high pressure
over the area. Some showers will be possible in the north on
Wednesday.
&&
.MARINE...
Short Term...Northeast pres gradient will increase this evening
as a surface trough passes. SCA`s will be in effect for the
outer waters for the overnight into Monday.
Long Term... Northeast flow continues for several days as high
pressure settles into northern Maine. Pressure gradient
gradually relaxes with winds dropping below advisory levels
sometime on Monday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until noon EDT Monday for ANZ150-152-154.
&&
$$
SYNOPSIS...
NEAR TERM...Cempa/Marine
SHORT TERM...Marine
LONG TERM...Kimble
AVIATION...
MARINE...
Area Forecast Discussion
National Weather Service Huntsville AL
920 PM CDT Sat Mar 24 2018
.NEAR TERM...(Rest of tonight)
Issued at 920 PM CDT Sat Mar 24 2018
Isentropic upglide preceding an approaching area of low pressure
(that was situated over NW Tennessee), was producing mainly light
showers across the area - mostly near and east of the I-65 corridor.
To our NW, a thunderstorm that at times has pulsed up to severe was
moving to the SE across W Tennessee east of the surface low. This
storm earlier produced damaging winds and large hail over the
MO/KY/TN border area. Output from the HRRR and RAP suggests this
convection should weaken as it nears this region late this evening
and early Sunday morning. The above mentioned upglide should also
diminish from NW-SE during the course of the overnight, as the low
moves across the region.
Given the showers already in progress, have raised rain chances into
the likely range into the mid/late evening, then have them lowering
from NW-SE during the overnight. The upglide may produce a rumble of
thunder or two in some of the stronger showers into the late evening.
However chances of this are too low to add this to the forecast for
this update.
Temperature forecast overall look good. Did lower them a degree or so
for our eastern areas, to account for cold air advection following
the cold front.
.SHORT TERM...(Sunday through Monday)
Issued at 219 PM CDT Sat Mar 24 2018
Surface winds become west northwest rather quickly on Sunday as the
parent low slides to our south. The upper flow also becomes westerly
likely setting up a situation where the front will stall or become
somewhat ill defined just to our south. Any sufficient lift for
precipitation will likely be confined to our south. We may well see
some breaks in the clouds on Sunday but shallow trapped moisture will
likely allow any breaks to fill in rather quickly.
Ridging across the northeast United States into the Middle Atlantic
coupled with the front just to our south will eventually set the
stage for strong southeasterly flow on Monday. Will once again
introduce pops, increasing during the afternoon. Have also hedged
toward the higher end of guidance for the winds given the tightening
gradient with the onshore Atlantic flow.
.LONG TERM...(Monday night through Friday)
Issued at 219 PM CDT Sat Mar 24 2018
A dry start to the long term period will quickly come to an end after
Tuesday as a fairly strong cold front moves into the region. Upper
ridging encompassing much of the eastern CONUS will shift eastward
through the day on Tuesday, as a closed upper low digs into the
Desert Southwest and a northern stream trough digs out of Canada.
Meanwhile, at the surface, a cold front will trail south from its
parent low over the northern Great Lakes, southwestward through the
Mississippi Valley and into northeast Texas. Given the placement of
the ridge, the area should remain mostly dry through the day, though
low and mid level moisture will keep a mostly cloudy sky across the
TN Valley. Surface flow will generally be from the south and help
temps warm into the 60s, despite the cloud cover.
Rain chances will increase quickly Tuesday night as the cold front
pushes eastward. Models are still in disagreement with regard to how
strong the upper ridge will be during the period, and how much
progression the front will make. As has been the case over the last
few runs, the GFS is much more progressive in bringing the front
into NW Alabama, however it does stall it for several periods. With
that said, both the GFS and ECWMF seem to be keying in on the
Wednesday through Wednesday night timeframe having the highest chance
for widespread moderate to heavy rainfall as the front really makes
a push into the area. This will also be the period that we would
most likely see thunder, though at this point this looks to be a very
low chance. Will keep mention of isolated thunder given the strength
of the forcing and a little bit of elevated instability. The front
will then push east of the area Thursday and Thursday night as the
closed low over the SW phases with the trough digging out of Canada.
This will give the front enough momentum to finally shift the ridge
eastward. There are two notable differences between the 24/12Z model
runs compared to previous ones. First, models are a bit drier
overall, with less QPF amounts. Second, at least for the GFS, the
front does not sit over the area for quite as long as previously
advertised. All of this results in overall rainfall amounts maxing
out around 3.5 inches. Still a lot of rain and something that bares
watching but less than previous runs. The caveat to that is we are
still a good 4 to 5 days away and this will likely change over the
coming days.
As the front shifts east of the area Thursday night, high pressure
will build across the area. The ECWMF is still slower with the
progression of the upper trough and keeps lingering precip on
Friday. However, given some continuity in previous runs showing
drying during the morning hours, will keep most of the area dry
through the day. Northerly surface flow will keep temps cool, though
still looking at highs warming into 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 642 PM CDT Sat Mar 24 2018
Although VFR conditions prevailed across the central Tennessee
Valley, upgliding of lower level moisture and approach of a cold
front will bring better chances of showers across the region tonight.
As such with local/regional radars indicating light showers forming,
have added VCSH for the start of the TAF. Showers should become more
prevalent in the early/mid evening, with CIGs falling into the MVFR
range ~1500 ft AGL. Temporary reductions to IFR are expected late
tonight with the front passage. Slow improvements to high MVFR CIGs
~3000 ft AGL should occur late in the morning, with generally VFR
weather returning Sunday afternoon.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...RSB
SHORT TERM...15
LONG TERM...73
AVIATION...RSB
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Lincoln IL
827 PM CDT Sat Mar 24 2018
.UPDATE...
Issued at 827 PM CDT Sat Mar 24 2018
Remnants of today`s snow storm is sagging southward across west
central Illinois along with the associated shortwave. Conditions
will continue to improve and have dropped the WSW for Knox, Stark,
and Marshall Counties. Given the impact of the higher snow amounts
and still some gusty winds will likely retain the WSW from Peoria
eastward until the 10 pm expiration time. Have adjusted PoPs to
reflect trends.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 314 PM CDT Sat Mar 24 2018
Surface low moving into southwestern IL this afternoon as a short
wave aloft drops into the trough just to the east. Although the
fronts associated with the system have remained well to the north,
the short wave has had more than enough energy to lift relatively
rich RH into a prolonged winter storm for areas north of I-74.
Winter Storm warning will continue as some of the visibilities
sporadically drop in still intermittent heavier snowfall. A wintry
mix is the dividing line... generally along or just south of a
line from PIA to BMI to CMI. Visibilities further reduced by
strong winds gusting in excess of 35mph. These winds will
continue, eventually becoming more northeasterly. A short break is
in store for the area in the late afternoon before a weaker round
of precip drops southward in behind the low as it shifts to the
east. The airmass to the NE is far more dry at the surface, with
dewpoints in the teens in southern MI and northern IN. This dry
air advecting into the region is what should be working on
clearing the skies per HRRR et al. The erosion of the moisture is
already evident on the radar mosaic in the region. Models have the
sky cover breaking up by midnight and moving the drier air into
place to avoid any significant visibility drops. Think that the
erosion of the cloud cover may be slightly overdone... and have
kept some of the clouds in place through the overnight in the
south.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 314 PM CDT Sat Mar 24 2018
Moving into the extended, a quiet end to the weekend as sunny
skies return, albeit with a cooler airmass and temps only climbing
into the upper 30s/lower 40s. The weak ridging aloft shifts to the
east and the flow into the region becomes more southwesterly
aloft. Weak warm advection as well as increasing available
moisture sets up the region for another bout of precip, dominating
the forecast with pops from Monday through Tuesday night. In that
time frame, the warm air advection brings the highs up to near 60
for Tuesday, even as the rain continues. By Wednesday early, the
front is moving through, limiting the highs to the 50s. The
forecast dries out for a couple days at least with more seasonable
temperatures. Both the GFS and ECMWF are hinting at a secondary
wave diving into the more broadscale trof over the CONUS, bringing
more precip to wrap up the work week into next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 600 PM CDT Sat Mar 24 2018
Precipitation winding down this evening across central Illinois as
shortwave pushes southeast of area and drier air evident over
northeast IL advects into terminals. Any precipitation should end
fairly early in the TAF period, but MVFR Cigs will likely linger
well into the night. High pressure over southern Quebec will
ridge into the area Sunday giving a brief respite prior to the
next weather system. Winds should remain in the 10-20 kt range.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 10 PM CDT this evening for ILZ029-031-
037-038-045-046.
&&
$$
UPDATE...Barker
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Barker
Area Forecast Discussion
National Weather Service Louisville KY
1005 PM EDT Sat Mar 24 2018
.Forecast Update...
Issued at 1000 PM EDT Sat Mar 24 2018
Cancelled the Winter Storm Warning early since precipitation has
changed over to all rain. Precipitation will continue to slowly
diminish from north to south tonight. T-storms with small hail will
continue to be possible through around midnight mainly over central
and southern KY. Late tonight precipitation will change over to
very light rain showers and patchy drizzle before ending completely
Sunday morning.
Low temperatures tonight will dip into the upper 20s over southeast
IN and the northern Bluegrass tonight so did send out an SPS about
black ice for that area. The rest of southern IN/central KY should
see lows in the 30s.
Issued at 700 PM EDT Sat Mar 24 2018
Cancelled the Winter Wx Advy early this evening as precipitation in
the advisory area has changed over to primarily rain and calls to
local officials reveal little if any lingering travel impacts.
Did keep the Winter Storm Warning in place as this area is still
receiving a mix of snow/sleet and many area roadways remain slick
and hazardous. Precipitation does look to wind down over the area
between 0-3Z so the Winter Storm Warning may potentially be
cancelled a bit earlier than 2am EDT.
&&
.Short Term...(This evening through Sunday night)
Issued at 249 PM EDT Sat Mar 24 2018
The widespread heavier precipitation has moved out of the area this
afternoon. Current radar shows very light rain/snow drizzle in
between heavier showers. With the cold air aloft these heavier
showers will be capable of producing small hail up to pea size.
Temperatures at the surface and aloft remain quite cold in the
Winter Weather Advisory and Winter Storm Warning areas. These should
warm a bit over the next few hours, but the potential for some snow
and sleet mixing in at times remains. The latest HRRR continues to
indicate an increase in precipitation coverage through the late
afternoon hours in these areas, so will keep the headlines going for
now as a precaution. However, impacts and additional snow and sleet
accumulations will be more spotty.
Through the overnight hours, precipitation will come to an end from
north to south. Temperatures will bottom out tonight in the upper
20s in far norther KY and portions of southeastern IN and in the
upper 30s across south central KY.
Drier weather is then in store for the remainder of the short term
period as weak ridging builds in aloft. Skies will still stay partly
to mostly cloudy tomorrow with highs in the 40s to lower 50s. Lows
will bottom out in the mid 30s to lower 40s on Sunday night.
.Long Term...(Monday through Saturday)
Issued at 305 PM EDT Sat Mar 24 2018
Ridging aloft will continue to build over the area on Monday. The
axis of this ridge will then shift slowly eastward through midweek.
At the surface, a warm front will approach on Monday and will move
north across the region through Monday night.
Monday will start out dry, but showers associated with the
aforementioned warm front will start to move in from the southwest
in the afternoon. This rain will continue to push north overnight.
Tuesday looks to be dry for at least a portion of central KY and
possibly most areas south of the river. Southerly winds will pick up
ushering in warmer air. The current forecast has highs topping out
in the low to mid 60s, but if there is some sun and dry conditions,
temps could be higher than that.
A slow moving cold front will then move through Wednesday into
Thursday. Rounds of showers are expected along and ahead of this
front beginning on Tuesday night and lasting through at least
Thursday. Rain with this system could be heavy at times. WPC still
has much of the area in a broad 3-4 inches of rain through the next
7 days. Given this we could start to see some minor river
flooding/areal flooding by the end of next week.
&&
.Aviation...(00Z TAF Issuance)
Issued at 750 PM EDT Sat Mar 24 2018
Periods of showers will continue at the TAF sites through 03z this
evening before winding down. Still can`t rule out a VCTS over the
next hour or two. Low-level clouds will push south of HNB/SDF/LEX
late tonight as low pressure moves southeast through Tennessee. IFR
and Fuel Alternate ceilings will likely persist into Sunday morning
at BWG. There are some indications BWG could lift to high-end MVFR
shortly after 12z Sunday, but other data suggests they will stay
socked in at 1500 ft all day long. Decided on improving conditions
by mid-morning, but MVFR is likely the rest of the day.
Expect breezy northeast winds through this TAF period. Did include
some LLWS at the northern TAF sites. The easterly low-level jet
ramps up to around 45 kts overnight.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...AMS
Short Term...EER
Long Term...EER
Aviation...EBW
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
922 PM CDT Sat Mar 24 2018
.UPDATE...
920 PM CDT
Have canceled the remaining counties that were in the WSW
(southern LaSalle, Livingston, Ford, Iroquois) a bit early with
that snow having ended. Based off IDOT road conditions map, it`s
likely that some roads remain snow covered, particularly
county/local roads, so travel will remain hazardous in spots.
Skies will clear overnight, but with east winds remaining
elevated, have some doubt on how much temperatures will be able to
drop, so adjusted mins upward slightly for now.
On Sunday, there should be a good deal of sunshine other than
some high clouds, so considering time of year, most areas without
snow cover should be able to rise well into the 40s, thus adjusted
highs up 2-4 degrees, topping out in upper 40s in spots.
Exception will be shore areas, especially IL side, kept around 40
by east flow. Attempted to account for sharp snow cover gradient
in southwest 1/3 of CWA, holding highs in roughly 39-42 range
where deepest snow cover resides. The snow will quickly melt and
compact in the strong late March sun, but it should have some
cooling influence.
Castro
&&
.SHORT TERM...
213 PM CDT
Through Sunday...
For headline purposes, we will likely drop the Winter Weather
Advisory for Ogle County in north central IL, Kankakee County of
east central IL, along with Newton and Jasper counties of NW
Indiana, as dry air is now winning outside of the moderate to
heavy snow band. Will leave the warning areas as is, and Benton
County, IN in an advisory with its close proximity to the moist
airmass. The the main impacts expected through the afternoon.
Fascinating dewpoint contrast is in place from area in the snow
to areas not very far upstream (Kankakee and Rensselaer in the
teens, with Lafayette, IN near 30 and same for Pontiac, IL). This
means the difference between 9-10" snow reports across Whiteside
and Carroll counties of northwest IL to little to nothing across
Winnebago and Ogle counties of north central IL.
Near whiteout conditions were been reported across portions of
Livingston, southern Lasalle, and Ford counties earlier, and now
winds are weakening some as the main surface low continues to
shift toward the Ohio valley and will continue even farther south
and west. That said, conditions are still very dangerous,
including along I-39, I-80, and I-55 in the warned areas. There
is still some lingering mesoscale frontogenetical forcing that
will remain in place across the I-24 corridor through the heart of
the warning area, and this combined with several more hours of
continued upper level support from the southeastward sinking upper
low will still maintain moderate to heavy snow potential. The
main instability axis is still just to our south and west, thus
think thunder chances are small, but elevated mid level lapse
rates will graze the area also (and suggested by the bumpy visible
satellite pics). Highest report of snow are in Chatsworth where
6" has been exceeded thus far.
RAP guidance does diminish the mesoscale forcing later this
afternoon and early evening. This along with the upper low
beginning to fill and a steady decrease in mid and lower level RH
(noted by the continued southwestward advance of the radar echoes
(that were attempting to shift NE) will suggest a rapid tapering
this evening.
The upper low will quickly sink south and be replaced the the high
pressure portion of the rex block in place, and there we will even
gradually thin out the higher moisture as well. Surface high
pressure will remain locked in place through the night over the
northern Great Lakes, and thus weaker but continued breezy NE
winds and chilly temperatures in the 20s. The pattern changes
little into Sunday, with continued cool east/northeast flow
suggesting highs in the lower 40s away from snow covered areas and
near the lakeshore where upper 30s may only be realized with the
March sunshine.
KMD
&&
.LONG TERM...
217 PM CDT
Sunday night through Saturday...
An increasingly meridional pattern will set up across the country
during the upcoming week setting the stage for periods of active
weather and temperature swings across northern Illinois and
northwest Indiana.
A deep upper trough is expected to develop over the Rockies while
a strong upper ridge will develop along the east coast.
Southwesterly jet stream will park between these two features over
the local area. A broad region of warm air advection will lift
across the region Monday and Monday night as this southwest flow
pattern develops while initial positively tilted shortwave lifts
across the Great Plains into the Upper Midwest. A weak surface
reflection will be present which will help transport surface warm
front north across the forecast area Monday afternoon and evening.
Showers and a few thunderstorms are expected as this occurs later
in the day Monday. A strengthening low level jet will help to
transport around 1.3 inch PWats into the area Monday night and may
serve as the focus for heavier showers overnight and into the day
Tuesday. Despite the expected precipitation and associated cloud
cover, warm advection will help drive a warming trend Monday and
Tuesday with afternoon highs in the upper 40s Monday and mid to
upper 50s expected by Tuesday.
Upper trough axis shifts into the northern Great Plains and Upper
Midwest midweek pushing the moisture axis off to our east. A
surface cold front will push across northern Illinois and
northwest Indiana Tuesday night into early Wednesday bringing
another chance for precip and result in a modest cooling trend
through the latter half of the week. A reinforcing cold front is
expected Thursday which will return us to below normal conditions
Friday into the weekend.
BMD
&&
.AVIATION...
For the 00Z TAFs...
VFR conditions through the period. Gustiness of the easterly winds
should ease this evening, but will probably become gusty again mid
morning through early-mid afternoon Sunday.
- Izzi
&&
.MARINE...
217 PM CDT
Easterly flow will prevail across the western Great Lakes through
the remainder of the weekend as a strong high slowly moves from
James Bay east across Quebec. A weakening area of low pressure
moving east across the mid Mississippi Valley today will continue
to cause near gale force gusts into the evening hours, but winds
should diminish gradually overnight into Sunday as the low fills.
Another low will form over the Colorado Front Range this weekend
and lift to Wisconsin early Tuesday then NNE across Lake Superior
through the day Tuesday. Out ahead of this feature, winds will
back to the southeast on Monday then to the SSW on Tuesday,
gusting to around 30 kt much of this time. There may be a brief
window of gales Monday afternoon into the evening, then the gale
threat should diminish Monday night as more stable conditions
develop as warmer and higher dewpoint air advects over the lake.
Will have to keep on some fog potential as this occurs. A cold
front will sweep across the lake Tuesday night with winds veering
to the NNW in its wake.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...IL nearshore waters until 4 PM Sunday.
Small Craft Advisory...IN nearshore waters until 10 AM Sunday.
&&
$$
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Area Forecast Discussion
National Weather Service San Francisco Bay Area
902 PM PDT Sat Mar 24 2018
.SYNOPSIS...Scattered showers will continue overnight with
isolated showers possibly lingering into Sunday. Dry weather is
expected to return on Monday and continue through next week. A
warming trend is forecast for the first half of the week.
&&
.DISCUSSION...As of 9:00 PM PDT Saturday...Evening satellite
imagery shows an upper low centered near the southern Oregon
coast, moving slowly to the east-southeast. To the south of this
low center, bands of showers are rotating onshore. Radar currently
shows a couple of bands of showers moving through the central and
southern SF Bay Area. Latest HRRR shows scattered showers
continuing through the night, mainly across northern and western
portions of our forecast area. A few lightning strikes were
recently detected up near Cape Mendocino, but it`s very unlikely
that thunderstorms will develop much farther south than that
overnight as the coldest air aloft remains well to our north.
Models indicate that widely scattered showers will linger into
Sunday morning, mainly near the coast. But showers are expected to
end in most areas by midday as the upper trough moves off to the
east. However, the 00Z NAM shows a few showers developing across
the far eastern portion of our forecast area on Sunday afternoon
as a weak disturbance drops in from the north. A recent forecast
update included adding slight shower chances to the hills of
eastern Napa County and eastern Santa Clara County tomorrow
afternoon. But for most of our area, Sunday afternoon is expected
to be dry and cool, with brisk northwest winds near the coast in
the afternoon. Gusty northwest winds are expected to continue in
coastal areas through Monday evening.
Temperatures over the next two nights are forecast to be as much
as ten degrees cooler than normal. Low temperatures are expected to
dip into the mid 30s in the coolest inland valleys through Monday
morning.
An upper ridge currently centered over the eastern Pacific along
145W is forecast to shift eastward towards the West Coast and
amplify through the middle of next week. This will result in dry
weather through the week, along with a warming trend across our
region from Monday through Thursday. By Wednesday, look for
widespread high temperatures in the 70s, with even a few lower 80s
possible.
&&
.AVIATION...As of 04:35 PM PDT Saturday...For 00Z TAFs. Winds
across the region out of the WSW to W with gusts to around 20-23
kt. Winds will remain gusty over the next few hours. Another weak
boundary is expected to move through over the next couple hours
with another round of showers spreading north to south. As the
boundary approaches, expect cigs to become BKN at 4,000 to 6,000
ft and then lower to MVFR. Conditions will rebound to VFR by
around 18z tomorrow has high pressure builds and conditions clear.
Vicinity of KSFO...Winds WSW to W gusting to just over 20 kt. Next
front to move through around 03-04z. May bring some showers to the
terminal along with MVFR cigs. Winds will decrease overnight and
cigs expected to lift late tomorrow morning.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Light showers remain in the vicinity with
BKN VFR cigs. Winds gusty out of the WSW to W to 20 kt at KSNS.
Winds will begin to decrease over the next few hours. Another weak
boundary will move through late tonight bringing possible showers
to the area along with MVFR cigs.
&&
.MARINE...As of 8:31 PM PDT Saturday...A cold front will pass
through the waters tonight, producing another round of scattered
showers. Winds will turn northwest and increase on Sunday behind
the front. Gusty northwest winds will continue into the early part
of the work week as strong high pressure builds off the northern
California coast. Winds will then gradually subside by midweek,
especially in the nearshore waters, as high pressure weakens.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Reyes to Pigeon Pt 0-10 nm from 2 AM
SCA...Pigeon Pt to Pt Pinos 0-10 nm from 2 AM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm from 2 AM
SCA...Pt Arena to Pigeon Pt 10-60 nm until 3 AM
SCA...Pt Arena to Pt Reyes 0-10 nm
&&
$$
PUBLIC FORECAST: Dykema
AVIATION: AS
MARINE: Dykema
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Area Forecast Discussion
National Weather Service Omaha/Valley NE
605 PM CDT Sat Mar 24 2018
.SHORT TERM...(Tonight through Tuesday)
Issued at 308 PM CDT Sat Mar 24 2018
Latest water vapor imagery and mid-level RAP analysis indicates
weak short-wave ridging over the area behind a potent departing
shortwave trough currently moving east over central Iowa.
Upstream, a large trough has moved onto the Pacific northwest
coast and will send additional precipitation chances our way into
early next week.
Brisk northeast winds today will gradually turn to the southeast
overnight ahead of next lee cyclone deepening over northeast
Colorado. Low-level warm air advection increases into Sunday which
may allow light drizzle/freezing drizzle to develop across
northwestern portions of the CWA Sunday morning. Model trends
continue to lower QPF values but we will still keep drizzle to
light rain mention in for much of the day. Any light freezing
drizzle does not appear to last long and so is not anticipated to
be a much of an issue.
Better precipitation chances arrive later Sunday night and into
Monday in advance of an approaching western mid/upper-level trough.
A strong low-level jet Sunday night could lead to a few isolated and
elevated nocturnal thunderstorms. Also, ahead of this advancing
trough, strong low-level warm and moist advection will bring mid-
upper 40`s surface dewpoints into southeastern counties by Monday
afternoon. This is ahead of a surface front progged to extend
northeast from low pressure over the OK panhandle to north central
Iowa. Showers and thunderstorms are forecast along and around this
boundary into Monday evening.
.LONG TERM...(Tuesday night through Saturday)
Issued at 308 PM CDT Sat Mar 24 2018
A drier but cool airmass moves into the region behind departing
mid/upper level trough. A quick moving shortwave trough will drop
southeast through the Northern Plains bringing a quick shot of
precipitation to northern portions of the forecast area
Wednesday. Near-normal temperatures are expected throughout the
remainder of the week with highs generally in the 40s and 50s with
lows in the upper 20s to low 30s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 601 PM CDT Sat Mar 24 2018
MVFR cigs around FL015 are forecast to persist through Sunday
afternoon with east to southeast winds of 10 to 15kt. Areas of
drizzle or light rain could affect all TAF sites after 18Z, but
most likely at KOFK where IFR cigs and MVFR vsbys are possible
after 21Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Kern
LONG TERM...Kern
AVIATION...Dergan
Area Forecast Discussion
National Weather Service Nashville TN
745 PM CDT Sat Mar 24 2018
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Latest surface observations and radar imagery show cold front
quickly moving southward into northern zones this evening, and
currently extends from just south of Clarksville to near Gallatin
to north of Gainesboro. Temperatures remain in the mid 50s to low
60s south of the front, but quickly fall into the mid 40s to low
50s north of the boundary, so a sharp cooldown is anticipating
with frontal passage this evening. As far as precipitation, radar
shows widespread light rain and drizzle continues over most of the
forecast area with embedded heavier rain and a few thunderstorms.
Some stronger thunderstorms are ongoing across West Tennessee near
a weak low pressure area, but CAPE decrease rapidly near the
Tennessee River so expecting these storms to keep weakening as
they move into the cwa. Have raised pops areawide for the evening
hours based on radar, and have adjusted temperatures quite a bit
for the evening hours in line with the latest HRRR timing of the
cold front. Precipitation will quickly end for most of the area
after midnight as the low shifts eastward.
&&
.AVIATION...
00Z TAF DISCUSSION.
Cigs and Visibilities have fallen at all sites but CKV with the
passage of this last batch of mainly light showers. Don`t expect
any improvement this evening as a surface low pressure system
moves over the mid state and brings with it another wave of
showers and maybe some embedded thunderstorms. The best chance for
thunder looks to be at CKV. Mainly just showers expected at all
other sites. While visibilities might improve after the precip
moves through, the cigs will likely stay at MVFR or IFR heights
through Sunday morning. Winds will shift out of the north as the
low passes this evening and remain there throughout the remainder
of the forecast period.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Shamburger
AVIATION........11
Updated for 00Z aviation forecast discussion.
&&
.SHORT TERM...(THIS EVENING THROUGH Sunday NIGHT)
ISSUED AT 226 PM CDT SAT MAR 24 2018
Low clouds and lingering moisture is the issue through the period.
However, in the very short term, convection may be an issue.
Quite a bit of clearing has occurred over southeast Missouri.
Current SBCAPE is 200-400 and forecast soundings from the RAP
suggest that 1500 is possible late this afternoon. The question is
whether or not there can be an sustainable updraft. If so, then
some hail and possibly wind may accompany the storms. These will
quickly end shortly after 00Z.
WV imagery shows upper low over northern Missouri with the surface
low near Texas county in Missouri which is forecast to slide
southeast to around Paducah by 00z and exit the area by 03z.
Time height sections reveal lots of low level moisture that might
be difficult to mix out tomorrow except in the northeast
sections.
.LONG TERM...(Monday THROUGH Saturday)
ISSUED AT 226 PM CDT SAT MAR 24 2018
Confidence remains high for wet and fairly warm extended until late
in the week and into the weekend. Confidence decreases after
Thursday as models diverge in their solutions.
Starting Monday winds will slowly shift to a more southerly
direction. This will start to advect higher dew points into the
region as a warm front approaches from the south. There will still
be ridging aloft but with the southerly flow increasing and some
elevated instability with K index around 30c across the area will be
inclined to keep rain chances going. Also Showalters go negative
over SEMO in the morning. So will maintain mention of thunder at
least there and may extend farther east due to K index values. By
Tuesday the warm front will have lifted well north...placing our
region in the warm sector with the trailing cold front to our west.
There are still hints of elevated instability with Showalter near
zero and K index still around/near 30. Again that is strongest over
the western half and in the morning. The cold front will move
through late Tuesday and Bisect the area from north to south
Wednesday morning. This will make the best chance for the most
rainfall overnight Tuesday night. The front will be slow to move
through the area but still faster than previous thoughts. Will
continue rain chances Thursday and Thursday night as the upper level
trough shifts eastward toward the area. Now this is where the model
solutions start to diverge a little. Friday the upper level trough
should have pushed the surface system out of the area and this
should dry us out. May have to have a low chance mention as we head
into Saturday as a secondary or reinforcing cold front moves through
the region. Finally winds will start to pick up Late monday and
persist through the night. The strongest winds will take place on
Tuesday with gusts near 30 mph likely. Temperatures will above
normal the first half of the week then near to slightly below late
in the week as cooler and drier air makes its way back into the
region.
&&
.AVIATION...
ISSUED AT 628 PM CDT SAT MAR 24 2018
Main band of convection now south of KCGI/KPAH with northerly
winds. Could see some lingering showers at KEVV/KOWB for a few
more hours before our chances for precipitation dwindle. Low
levels are saturated so MVFR/IFR cigs will be commonplace. Could
see cigs rise toward the late afternoon hours at KCGI/KPAH,
although some eroding of the deck could occur earlier at KEVV with
drier air trying to make it in. Winds will remain northeasterly at
KEVV/KOWB but more northerly at KCGI/KPAH until Sunday morning
when they should shift northeasterly as well.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$