Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/22/17
Area Forecast Discussion
National Weather Service Gaylord MI
1151 PM EDT Sat Oct 21 2017
.UPDATE...
Issued at 1043 PM EDT Sat Oct 21 2017
Scattered high and mid level clouds continue to stream northeast
across the area, well ahead of a slow moving cold front back
across the Corn Belt. Not expecting too much change overnight,
with a slowly thicken cloud deck as the front makes slow progress
east. Moisture may become just deep enough across northern Lake
Michigan and surrounding shoreline areas to kick off a few very
light showers by sunrise. Otherwise, another unseasonably mild
night, with overnight lows only dropping a few more degrees into
the mid and upper 50s.
&&
.NEAR TERM...(Tonight through Sunday)
Issued at 333 PM EDT Sat Oct 21 2017
...Summer`s last stand...
High impact weather potential...elevated fire danger into early
evening, as well as in ne lower MI Sunday afternoon.
Deep southerly flow continues, well ahead of a cold front advancing
across western MN/IA. Mid/high clouds continue in northern MI
(with thinning in sw sections), but no cu, and surface dew points
have again mixed out into the 30s in a few locales. Wx thru
tonight will be mostly quiet, but showers will make a push into
the region Sunday, along with the associated cold front.
Any real low-level moisture is found pretty close to the incoming
cold front. Even though surface dew points are climbing into the 50s
in WI, the se half of the state has effectively no cloud cover. That
isn`t stopping elevated showers from popping along a moisture
gradient and vort ribbon aloft, from the STL area up to almost BEH.
This axis of elevated convection increasingly fades to virga with
northward extent. It`s going to difficult for this to generate
precip this far north; Nam tries to spit out a few showers, toward
and especially after 06z. Am not inclined to bite on this (the
RAP is dry, at least for that part of the area).
Pre-frontal moisture band does edge toward western sections very
late tonight. The Rap is occasionally spitting our some showers
ahead of the front, some of which impact the northern Lake MI
islands, and western Mack Co. A slight chance for a shower might be
justified here after 6am.
Min temps tonight in the 50s to near 60f, coolest in the interior of
ne lower MI, warmest along the Lake MI coast.
Much better rain chances arrive Sunday from w to e, with the cold
front across eastern upper and making inroads into nw lower MI
during the afternoon/early evening. Height falls aloft are subtle,
but present in the afternoon, especially in nw sections. The most
widespread precip is likely to be along and just behind the boundary
as it moves in. Chance pops warranted in nw lower and eastern upper
MI thru early afternoon. Likely to categorical pops push as far east
as Rogers/Mio/Gladwin by early evening, with only chance pops thru
00z/8 pm east of there. Rainfall amounts of a quarter-inch or so are
expected in the west half of the forecast area. We might be able to
muster 200-300j/kg of MuCape in northern lower MI. If coupled with
stronger forcing, would be comfortable mentioning isolated thunder.
But we don`t really have that, and will omit any thunder mention for
now.
Max temps Sunday mainly in the 70s (some upper 60s near Lake MI).
Another day of elevated fire danger in ne lower MI, with warm temps
and gusty winds ahead of incoming precip. However, RH levels will
be higher than today.
&&
.SHORT TERM...(Sunday night through Tuesday)
Issued at 333 PM EDT Sat Oct 21 2017
...The Gales of Late October...
High Impact Weather Potential...Gusty winds winds on Tuesday and
Tuesday night.
Pattern Synopsis/Forecast...The cold front is part way through the
forecast area at 00z/Mon and looks to take the next 12 hours to move
through the rest of it. However, The ECMWF looks to slow down a bit,
as the 500 mb trough digs in behind the front. Another piece of
energy then digs into the 500 mb trough and begins to close off the
trough into a closed low, on the ECMWF. The GFS is a little slower
doing this overnight, so that by 12z/Tue the 500 mb closed low is
somewhere over the Upper Great Lakes. The sfc low then deepens and
moves to the N-NE, but at different speeds. This will affect the
winds, as the ECMWF will be much windier behind the low than the
GFS. We are looking at Gales over the Lakes either way, but the
ECMWF could be showing gustier winds. Will wait on the next run or
so to figure which way the models are going with this.
Primary Forecast concerns...We can use a good soaker again, and
while we will get a decent amount of rain, but think that it will be
below the 2.5" in 6 hours that we would need for flooding. The other
issue of concern, as alluded to in the previous section, is the
forecast low track. If the ECMWF is right, it could end up quite
windy with gusts to 40 mph so possibly some sort of wind headline.
The GFS has moved the center of the low out, well north of the Upper
Great Lakes, and the resultant gradient will support low end gales
on the lakes, but probably not wind headlines on the land. So will
have to watch the direction of the models.
.LONG TERM...(Tuesday night through Saturday)
Issued at 333 PM EDT Sat Oct 21 2017
...Cooling off, but Continued at or Above Normal...
Extended (Tuesday night through Saturday)...The pattern definitely
looks to be flipping back to a fall like pattern with the usual
strong wind storms that usually move through the Great Lakes this
time of year. This also opens up the possibility of mixed
precipitation, mainly at night and at interior, higher elevation
locations, as we get close to the end of October. Tuesday night we
start off in the midst of the first 500 mb closed low of days 4-7.
It looks to try to lift out on Wednesday, only for a piece of energy
to move into the back side of the low and retrograde it a bit before
exiting and allowing the trough to lift out of the Upper Great Lakes
by 12z/Thu. This will definitely cool us down and bring periods of
rain through the Wednesday night. Expect a brief dry period for
Thursday before the next bowling ball of cold air and rain moves
into the region for Friday and Saturday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1148 PM EDT Sat Oct 21 2017
VFR conditions through this morning will give to deteriorating
conditions this afternoon and evening as a slow moving cold front
moves into the region. Band of light to moderate showers will
spread west to east very slowly across the taf sites later today
and tonight, likely bringing some vis restrictions and IFR cigs
along with them. Somewhat gusty south winds today will become
northwest as the front passes.
&&
.MARINE...
Issued at 333 PM EDT Sat Oct 21 2017
Breezy southerly winds continue thru Sunday morning. A sharp cold
front will slowly push into northern MI Sunday afternoon and
night, with nw winds behind it. This front will also bring
widespread showers beginning Sunday afternoon.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY until 6 PM EDT Sunday for LMZ323-341-342-
344>346.
LS...NONE.
&&
$$
UPDATE...MB
NEAR TERM...JZ
SHORT TERM...JL
LONG TERM...JL
AVIATION...MB
MARINE...JZ
Area Forecast Discussion
National Weather Service La Crosse WI
638 PM CDT Sat Oct 21 2017
.SHORT TERM...(This evening through Sunday)
Issued at 230 PM CDT Sat Oct 21 2017
Water vapor satellite this afternoon shows the mean long wave trough
has progressed through the Rockies. The trough and embedded short
wave troughs will continue to work east through the night and then
start to shear out Sunday as a closed upper level low looks to take
shape across the lower Mississippi River Valley. This trough and
embedded short wave troughs will provide the necessary lift for
showers and storms along the cold front. Out ahead of the front,
there is a strong cap in place above 800 mb and the 21.17Z RAP and
21.12Z NAM forecast soundings continue to show this cap will remain
in place until the front arrives this evening. This will provide a
very narrow window where there will be enough forcing and CAPE to
support thunderstorms right along the front. Forecast soundings from
the RAP show between 500 and 750 J/Kg of CAPE along the front in a
tall, skinny profile with deep layer shear of 30 to 40 knots, most
of which resides in the lowest 3 km. The main concern continues to
be if this CAPE profile will be enough to balance out the shear and
allow some stronger to potentially severe storms to form. If it
does, strong to damaging winds continue to look to be the main
threat and in that regards, no real change to current thinking or
messaging. The storms should also be efficient rain producers with
precipitable waters expected to be in the 1.5 to 1.75 inch range and
warm cloud depths around 3.5 km. Expecting the front with the
showers and storms to start moving into the western sections of the
area right around 22.00Z and then move steadily east across the area
through the night. The threat for strong to severe storms should
diminish by late evening as the CAPE becomes minimal. Lingering
showers behind the front Sunday morning, mainly over Wisconsin, will
come to an end by early afternoon. The clouds will take a bit longer
to clear but look for skies to become mostly sunny starting in the
morning across the west and during the afternoon for the eastern
sections.
.LONG TERM...(Sunday night through Saturday)
Issued at 230 PM CDT Sat Oct 21 2017
Much cooler weather still expected for this coming week. Overall,
little change made to the previous forecast, although forecast
confidence erodes heading through the middle and latter stages of
the week.
There will be one more mild/seasonable day Monday ahead of an
upper trough that will dig southeastward towards the Great Lakes
and drive a strong cold front through the area on Monday.
Following the frontal passage, temps will fall below average on
Tuesday with highs in the 40s to near 50. As the cold air aloft
and steep low-level lapse rates interact with weak ripples within
the upper trough, some showers are possible especially Monday
night into Tuesday, with otherwise mostly cloudy, breezy and
chilly conditions. Some differences exist Tuesday night into
Wednesday with the 21.12Z GFS a little farther southwest with a
reinforcing shortwave trough in northwest flow compared with the
ECMWF, bringing light precip and increased clouds to the area.
This could ultimately impact low temps and possible frost concerns
Wednesday morning.
Short-lived shortwave ridging is expected on Thursday with return
southerly flow helping temps moderate to near or slightly above
seasonal norms ahead of low pressure developing to the west.
Beyond Thursday, confidence in forecast details remains lower,
especially regarding any precip chances. Deterministic and
ensemble guidance both support another upper trough moving into
the central US late this week, a little farther west than the
early week trough. A reinforcing surge of cooler, below average
temps is expected for Friday/Saturday (850 mb temps falling to -6
to -9C by Saturday), with another chance for a widespread
frost/freeze by late this week. However, run-to-run consistency
among models has been poor during this time with the evolution of
the upper trough, so stuck with model consensus pops late this
week for now. It`s possible it could be cold enough for some
snowflakes by late this week with any precip.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 638 PM CDT Sat Oct 21 2017
A cold front continues to approach the area, and will arrive at
RST around 02Z and LSE by 06Z. Ahead of that front, a relatively
brief period of showers and thunderstorms is expected, with
temporary MVFR conditions possible along with potentially some
brief gusty winds to around 25 knots. Behind the front, RST
should dry out fairly quickly by around midnight at the latest,
but additional showers are expected to develop near and east of
the Mississippi River, impacting LSE through sunrise if not a
little later. Also behind the front, ceilings will gradually rise
into Sunday, with skies expected to clear entirely for RST by
early afternoon while thicker cirrus hangs on around LSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...04
LONG TERM...JM
AVIATION...Lawrence
Area Forecast Discussion
National Weather Service Caribou ME
921 PM EDT Sat Oct 21 2017
.SYNOPSIS...
High pressure will build over the area tonight then move east of the
region Sunday into Monday. A trough of low pressure will approach
from the west on Tuesday.
&&
.NEAR TERM /THROUGH SUNDAY/...
9:21 PM Update...High clouds are spilling over an upper ridge
that is building to the west of the region. The high clouds are
not having a big impact on temps as the northwest valleys have
quickly dropped to around the freezing mark. It is still a
relatively mild 55F at Bangor as of 9 PM. The main update was to
the temperatures to reflect the temperature trend so far this
evening, and the expected conditions the remainder of the night.
Previous discussion...
A chilly night upcoming and milder for Sunday.
High pres expected to slide e overnight into Sunday. This will
lead to some waa to start kicking overnight w/a return flow
around the high. We tend to see some cold temps w/a setup such
as this one setting up tonight. Decided to undercut the
overnight temps by a few degrees w/some northern and western
areas seeing the upper 20s. It looks like a decent inversion
will set up later tonight as shown by the RAP and NAM12
soundings. There will be quite a variation in temps as low lying
areas as far s as the downeast region will see temps in the
30s. Clouds are expected to move in later tonight w/most of
thicker cloud cover across the southern 1/2 of the CWA. Most of
the cloudiness with be cirrus around 25,000 feet.
For Sunday, the clouds will lift to the ene by the afternoon as
the upper ridge moves across the region. This will allow for
more sunshine and w/a light ese flow, temps should rise well
into the 50s and 60s across the region. Areas close to the coast
will be cooler w/the onshore flow.
Fire Danger is a concern for Sunday. See the Fire Weather
section below.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
High pressure moving to the east combined with strong upper level
ridging will bring a mild night Sunday night followed by a sunny and
warm day on Monday. A southerly breeze will increase on Monday
behind departing high pressure. Monday night will be unseasonably
warm as the circulation behind departing high pressure continues.
Some low clouds may begin to stray in Downeast areas late at night
as low level moisture increases. The southerly wind will increase on
Tuesday in the increasing gradient between high pressure off to the
east and a trough of low pressure approaching from the west. Low
clouds will spread across the area as moisture continues to increase
and some patchy mist or drizzle is possible, especially
Downeast.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A digging trough of low pressure approaching form the Midwest will
be pushing up against a strong ridge of high pressure to our east
Tuesday night into Wednesday. A corridor of deep subtropical
moisture will be channeled north our way Tuesday night into
Wednesday bringing bands of showers, some possibly heavy, as the
trough pushes east into our area. A wave of low pressure will likely
form off the Mid-Atlantic coast on Wednesday, then channel north
from there as very strong ridging well to our east holds the frontal
boundary over our region. This will bring the potential for some
bands of potentially heavy rain across the area later Wednesday into
early Thursday. The moist frontal boundary should lift northeast and
away from the area Thursday night into Friday as the upper trough
lifts northeast.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR right into Sunday.
SHORT TERM: VFR conditions are likely Sunday night into early
Monday night. Conditions may lower to IFR Downeast late Monday
night as some low clouds begin to spread in from the south. IFR
to MVFR conditions are likely Tuesday into Wednesday in low
clouds, some drizzle, and showers Tuesday night into Wednesday.
&&
.MARINE...
NEAR TERM: No issues on the waters. Winds will remain light 5 to
10 kts into Sunday w/a turn to ese by the afternoon. Seas will
range 1 to 2 ft especially in the intra-coastal zone.
SHORT TERM: Winds are expected to be below SCA Sunday night
into Monday night. South winds may reach SCA on Tuesday and seas
will likely build in response to the southerly winds. A SCA or
Gale will likely be needed Tuesday night into Wednesday for
strong south winds. Seas will continue to build due to the
southerly fetch possibly reaching 10-15 ft on Wednesday.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...CB/Hewitt
Short Term...Bloomer
Long Term...Bloomer
Aviation...CB/Hewitt/Bloomer
Marine...CB/Hewitt/Bloomer
Area Forecast Discussion
National Weather Service Des Moines IA
627 PM CDT Sat Oct 21 2017
.SHORT TERM.../Tonight through Sunday/
Issued at 312 PM CDT Sat Oct 21 2017
The primary concern will obviously be convective trends into
tonight. Confidence is high that showers and storms will blossom
eventually due to the deep convergence and deep, strong
thermodynamic and kinematic forcing with the long wave trough
passage, but less so with respect to intensity. Storms developed in
NW Iowa around 18z and looked as if they were going to mature fairly
quickly, but since diminished. Additional convection has also
developed farther south in a zone of strong frontal convergence and
frontogenetical forcing, but this has also been somewhat slow to
strengthen. Western Iowa RAP soundings show a 2km warm layer at the
base of the EML continuing to erode and there may be a slim window
for surface based convection to mature, but it will not last long as
the front quickly undercuts anything resulting in convection being
rooted around 1km. With plenty of stratus over Iowa and the loss of
heating soon, feel much of the convection will be below severe
limits unless trends increase soon.
Shallow and deep shear parameters are both high so there remains a
small potential for supercells and brief tornadoes in addition to
hail and wind. QLCS tornadoes will be possible into the evening with
low level shear persisting, but as mentioned overnight the 0-3km
shear vectors are not oriented favorably: too far to the north vs
east and line/front orientation. Small segments would need to orient
NE to realize available shallow shear and SRH. Moderate to locally
heavy rains may eventually be a greater threat with strong low level
moisture transport ahead of the front. 00Z NAEFS precipitable water,
specific humidities and integrated water vapor transport are all
near climatological extremes. Thus expect widespread efficient rains
in 3.5+km warm cloud depths with 1 amounts over the SE half of the
forecast area possible by tonight.
Skies should clear into tomorrow as the system departs with
temperatures 5 to 10 degrees cooler than today. The biggest change
will be less humid conditions with surface dewpoints no better than
the 30s and 40s.
.LONG TERM.../Sunday night through Saturday/
Issued at 312 PM CDT Sat Oct 21 2017
The long term period begins with significant shortwave trough diving
south through the Upper Midwest early next week. This will send a
strong cold front through central Iowa during the morning and
afternoon hours on Monday. Deep unidirectional winds and efficient
boundary layer mixing behind the front should still be enough to
warm temperatures into the upper 50s and low 60s. Not expecting
anything more than isolated showers with the frontal passage as the
atmosphere is starved of moisture. A reinforcing shot of cold air
advection will lead to much cooler and blustery conditions on
Tuesday. Model guidance remained consistent to the previous forecast
with highs only in the upper 40s and low 50s.
A bounce back to near average temperatures is expected through the
middle of the week as an upper level ridge builds over the Plains
states. The warm up will be short lived as a deep upper level low
digs southeast and dislodges a large dome of cold air to our north.
The GFS and EC remain out of sync with their timing and evolution of
the trough, although the slower EC has trended toward the faster GFS
with the latest run. Regardless of any model discrepancies, there is
high confidence that the coldest air we have seen so far this season
will be ushered in by a strong cold frontal passage in the late
Thursday or Friday time frame. Latest guidance suggests highs will
struggle to get out of the 40s on Friday and Saturday with below
freezing temperatures possible overnight. Light rain and/or a few
snow flakes are also possible Friday night into Saturday as moisture
wraps around the back side of the upper level low. At this time it
looks like the better lift/moisture will slide north of the area.
&&
.AVIATION.../For the 00Z TAFS through 00Z Sunday evening/
Issued at 627 PM CDT Sat Oct 21 2017
Broken line of convection with occasional MVFR cigs moving across
area now...and will exit the far east by 10-12z Sunday. Activity
may increase southeast overnight near KOTM as low level jet
increases aft 03z. Some wind and mainly MVFR VSBY reduction as
storms roll through. Aft 06-10z nearly all areas will be VFR with
either high clouds or skc aft 12z. Winds increase aft 15z with
gusts near 16-18kt until 21z. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Small
LONG TERM...Martin
AVIATION...REV
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
917 PM CDT Sat Oct 21 2017
.UPDATE...
The much talked about cold front is currently headed south and
located across a Wichita Falls to Odessa, Texas line. Along it,
strong to severe thunderstorms are ongoing across north Texas and
Oklahoma. However, as the front continues to shift south, the
stronger lift and forcing dynamics will remain north in association
to the vorticity maximum over Oklahoma. Wile SPC mesoanalysis and
suggested GFS/NAM BUFR soundings indicate upwards of 2000 J/KG of
MLCAPE over the region, a strong cap is also in place per these same
sources. Furthermore, aircraft data out of Austin and San Antonio
also indicate the presence of the capping inversion. This will keep
any pre-frontal activity at bay through the evening. The showers over
San Saba to Comanche Counties north of the area are elevated in
nature due to the overspreading of weak upper-level divergence. RAP
mass fields indicate surface convergence will weaken as the front
passes through the region while the best mid- and upper-level support
lag behind. A strong thunderstorm or two may still be possible with
the passage of the front overnight but overall trends appear to
suggest only pockets of brief heavy rain and general thunderstorms
along a Fredericksburg to Giddings line and north. Have reduced rain
chances farther west and south through the overnight. The front
should be through the entire area by late morning to near noon Sunday
with gusty north winds but clearing skies.
&&
.PREV DISCUSSION... /ISSUED 717 PM CDT Sat Oct 21 2017/
AVIATION... /00Z TAFS/
Vfr skies remain expected through the evening with some areas of
1000-2000 ft cigs expected after midnight. Lowest cigs should be
limited to the higher terrain areas. A brief dip into ifr could be
possible right as the cold front arrives and areas of convection
congregate along the front. Frontal timing appears to be consistent
among the past several runs of rapid refresh models. Regarding the
potential for TSRA, would suspect that we`ll no longer need to
consider the TSRA prevailing at SAT/SSF by the 06Z update given the
mesoscale trends in the HRRR. However, have found that the convective
handling of the HRRR runs around the 00z init time often deviate
from the broader consensus of qpf for some reason. Thus will stick
with the earlier foreast trends and modify late this evening should
the 00Z runs reflect the decreasing TSRA potential. Post-frontal sky
conditions should improve rapidly Sunday morning given the deep
layer of northerly winds behind the font.
PREV DISCUSSION... /ISSUED 252 PM CDT Sat Oct 21 2017/
SHORT TERM (Tonight through Sunday Night)...
For the rest of the afternoon, a weak embedded disturbance within the
larger shortwave has disturbed CU fields enough to produce some
showers along and just east of the I-35 corridor near Austin and
Georgetown. Proximity soundings from just about all models show the
cap holding on to prevent much in the way of anything more than a
very isolated thunder chance but included slight chc PoPs for this
area and east for the rest of the afternoon.
The bigger forecast focus is the approaching cold front overnight
tonight that will trek across Texas and reach the northern CWA likely
just before dawn. The TTU-WRF has been consistent with timing of the
front while the HRRRX continues to speed up and generate more
convection with each run. Looking at the current speed of the front,
do think the faster HRRRX is valid thus have slightly sped up the
fronts arrival in the grids but only about an hour or so.
As far shower and thunderstorm potential, the main threat will be
gusty winds and not much else for hazards. Just about every CAM
produces healthy outflow with convection firing in northern Texas,
and with the faster trends in the front as seen in the HRRRX
previously noted, this would further add confidence in gusty winds
and limit any hail potential. Still seems to be some disagreement in
the western extent of the convective line. SPCs SSEO guidance shows
enough outcomes extending into the Plateau and Hill Country to
warrant at least chance PoPs during fropa Sunday morning. Thus have
reflected as such in the grids.
The front should be clear of the CWA by 18Z, resulting in a breezy,
mild day Sunday afternoon. Did bump up gust potential to a max of 30
mph late morning and mid day as a fairly strong pressure gradient
looks to be in place post fropa. These should die down by the evening
and allow for a very favorable radiational cooling set up with high
pressure, light winds, and clear skies. Thus, lowered min T for
Monday morning to the lower end of the ECM and MEN ensemble guidance.
LONG TERM (Monday through Saturday)...
A rather benign weather pattern for much of the week as Sunday`s
front dries out the area and gradual warming occurs through mid week.
Another cold front is progged to push through the area Friday which
may be a more significant temperature changer for South Central
Texas. At current, extended guidance shows highs next weekend
struggling to exceed 70 degrees at least for the northern CWA. Still
some model disagreement in timing and strength this far out so left
this to the SuperBlend for now. However, no hazards are expected
through the extended.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 65 77 50 83 55 / 80 20 0 0 0
Austin Bergstrom Intl Airport 65 79 47 83 53 / 80 20 0 0 0
New Braunfels Muni Airport 66 81 47 82 53 / 50 30 0 0 0
Burnet Muni Airport 60 77 45 81 52 / 90 10 0 0 0
Del Rio Intl Airport 64 81 51 83 56 / 10 - 0 0 0
Georgetown Muni Airport 63 76 46 82 53 / 90 20 0 0 0
Hondo Muni Airport 67 85 46 83 52 / 20 10 0 0 0
San Marcos Muni Airport 66 81 47 83 53 / 60 30 0 0 0
La Grange - Fayette Regional 68 79 47 81 55 / 70 60 0 0 0
San Antonio Intl Airport 67 82 49 82 55 / 30 20 0 0 0
Stinson Muni Airport 68 85 50 83 55 / 30 20 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Oaks
Synoptic/Grids...Allen
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
939 PM CDT Sat Oct 21 2017
.UPDATE...
Issued at 918 PM CDT Sat Oct 21 2017
A cold front was moving southeastward through northwestern MO
this evening. A line of convection was along this front with
trailing stratiform precipitation behind it. Isolated showers had
recently developed across parts of northeast and central MO well
ahead of the cold front. The line of convection will gradually
weaken as it moves into northeast and central MO around midnight
due to waning instability, but could still generate brief heavy
downpours along with strong gusty winds. Looking at the latest
HRRR model runs this convection will not likely get into the St
Louis metro area until very late tonight and early Sunday morning,
and by this time should have weakened quite a bit and be mainly in
the form of disorganized scattered showers. Unseasonably warm
temperatures can be expected tonight ahead of the cold front,
particularly across southeast and east central MO and southwest
IL due to the cloud cover, gusty southerly winds, and relatively
high surface dew points. Lows in St Louis metro area tonight will
be around 15 degrees above normal.
GKS
&&
.SHORT TERM... (Through Late Sunday Afternoon)
Issued at 308 PM CDT Sat Oct 21 2017
Main issue continues to be the cold front that will slide east
across region tonight through midday on Sunday. Models have decent
sfc based CAPEs thru this evening, then diminish quickly after 06z.
With slower onset of precipitation and weakening instability, feel
that as line of storms approach CWA, they will weaken and expect
mainly widespread showers and isolated thunderstorms with passage of
front. Still not ruling out isolated strong to severe storms for
portions of central/northeast MO late this evening.
Models now more in agreement with upper level trof deepening and
cutting off late in the day on Sunday. This will slow exit of
activity on back side of system, especially for eastern half of
forecast area.
As for temperatures, will see mild lows for one more night, in the
low 50s to mid 60s. Then on Sunday, morning highs in the low 60s to
low 70s, then steady or falling temperatures during the afternoon
hours.
Byrd
.LONG TERM... (Sunday Night through Next Saturday)
Issued at 308 PM CDT Sat Oct 21 2017
Period begins with amplified flow as a deep trof becomes
cut off across the region. Mdls are still struggling with this
feature. However, the 12z guidance is in much better agreement than
prev cycles and confidence is building. Still, have kept low PoPs on
Mon to account for a potential slower soln.
After a brief warmup on Mon, another cdfnt pushes thru the region
Mon afternoon as a deep low develops over the Great Lakes region.
The area shud remain seasonable cool with reinforcing shots of cold
air. A couple of clippers will help to warm temps as well. Mdls
differ late in the period with exactly how much cold air will arrive
Fri into Sat as another cdfnt pushes thru the region. The GFS/ECMWF
both point to low chances of snow Fri night into Sat, perhaps even
longer into Sat morning than currently forecast. A lot can change
between now and next weekend, but will be an event to monitor.
Tilly
&&
.AVIATION... (For the 00z TAFs through 00z Sunday Evening)
Issued at 526 PM CDT Sat Oct 21 2017
Cold front extending from MN south through extreme northwestern
MO into western OK will move southeastward through the taf sites
late tonight and Sunday morning. There was a line of thunderstorms
along this front which will move into UIN and COU late this
evening near midnight, and eventually into the St Louis metro area
by early Sunday morning. The convection should slowly weaken in
intensity late tonight as the instability wanes. There may also be
isolated showers ahead of the cold front which could impact the
taf sites this evening. Lingering light showers may continue in
UIN and COU during at least much of Sunday morning and in the St
Louis metro area Sunday afternoon due to a slow moving upper level
disturbance behind the cold front. MVFR cigs will advect into the
taf sites late tonight and early Sunday morning along and behind
the cold front. The ceiling should gradually improve to VFR
conditions Sunday afternoon. The southerly surface winds will veer
around to a northwesterly direction after fropa in UIN and COU
towards early Sunday morning and in the St Louis metro area by
early Sunday afternoon. There will be a strong southwesterly low
level jet tonight which will lead to some LLWS conditions at the
taf sites, but it appears that there will be enough nocturnal
mixing to keep the surface wind up so it will not likely be
strong enough to include in the tafs.
SPECIFICS FOR KSTL: Cold front extending from MN south through extreme
northwestern MO into western OK will move southeastward through
the STL area Sunday morning. There was a line of thunderstorms
along this front which will move into the STL area by early
Sunday morning. The convection should slowly weaken in intensity
late tonight as the instability wanes. There may also be isolated
showers ahead of the cold front which could impact STL this
evening. Lingering light showers may continue in the STL area
Sunday afternoon due to a slow moving upper level disturbance
behind the cold front. MVFR cigs will advect into the STL area
late tonight and early Sunday morning along and behind the cold
front. The ceiling should gradually improve to VFR conditions
Sunday afternoon. The southerly surface winds will veer around to
a northwesterly direction after fropa by early Sunday afternoon.
There will be a strong southwesterly low level jet tonight which
will lead to some LLWS conditions, but it appears that there will
be enough nocturnal mixing to keep the surface wind up so it will
not likely be strong enough to include in the tafs.
GKS
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 64 66 50 70 / 90 90 30 10
Quincy 57 61 45 68 / 100 70 5 0
Columbia 55 61 44 70 / 100 60 5 0
Jefferson City 57 62 43 71 / 100 70 5 5
Salem 64 72 50 67 / 60 90 60 40
Farmington 63 67 47 70 / 90 90 40 20
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
842 PM EDT Sat Oct 21 2017
.SYNOPSIS...
High pressure will move east into the western Atlantic through
Monday. Low pressure and its attendant cold front will sweep
through the area Tuesday. Troughing will remain overhead for
much of the second half of the week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
High pressure resudes across the Northeast and Mid Atlantic
section of the CONUS. In spite of this, ample upper level
moisture has drifed atop the ridge, resulting in a deck of
cirrus. Skies became mostly cloudy if not cloudy just prior to
sunset, and remains so at this time. IR satellite and RAP Bufkit
overview suggest there will be little change until the pre-dawn
hours. Have made these adjustments in the sky grids. Will be
assessing if low temperatures need to be bumped up slightly
shortly.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Quiet wx Sun-Sun night under high pressure. Clouds begin to
increase Mon with showers expected by midday on the west and
spreading east through the afternoon. Heavy showers with
possible t-storms and gusty winds Mon night as cdfnt enters the
area.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Strong front moving through Tuesday is main story in long term. This
system looks potent with potential for a period of heavy, wind swept
rain ahead of and along the primary cold front. Strong southerly
fetch ahead of it should bring copious moisture north, but speed
should limit flood concern. Gusty winds possible with very strong
low level jet, but most likely any winds of a threatening nature
will be limited to the cold frontal passage itself - low topped
squalls possibly embedded within larger rain band is the concern.
Timing remains a bit uncertain but right now, its favoring the AM.
Breezy and much cooler behind the front, with the coolest days
likely Wednesday-Thursday. Some freeze issues are possible, though
this cold shot looks very transitory and if it doesn`t align with a
good radiational night, it just might be chilly versus freezing.
Upper trough plus wraparound moisture might result in a few showers
Wednesday as well, especially in the mountains. If its cold enough
in the higher terrain, these could well be snow showers.
Drying out and moderating Friday with high pressure building in.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
VFR conditions through Sunday evening. A southerly flow will
strengthen ahead of a cold front overnight Sunday and Monday.
Moisture streaming into the area will cause more clouds along with
the possibility for subVFR cigs. Patchy fog is also possible
overnight. The cold front will pass through overnight Monday
into early Tuesday. LLWS is possible during this time.
A soaking rain is also expected with the frontal passage and there
is a potential for heavy rain and IFR cigs/vis, along with gusty
winds - perhaps isolated 30-40 knot gusts. Timing still a bit
uncertain but right now favoring between 06z-12z early Tuesday.
After that, NW wind may be gusty, but becoming VFR overall for the
rest of the week. A few showers possible, mainly Wednesday, but
cig/vis reductions should be minimal.
&&
.MARINE...
Winds will begin to strengthen Mon in srly flow. SCA conditions
likely by late Mon and solid SCA conditions expected Tue.
Gales possible Tuesday as strong cold front barrells through. SCA
possible Wednesday as the system moves away and high pressure builds
in.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.
&&
$$
SYNOPSIS...LFR
NEAR TERM...HTS
SHORT TERM...LFR
LONG TERM...RCM
AVIATION...BJL/RCM
MARINE...RCM/LFR
Area Forecast Discussion
National Weather Service Memphis TN
934 PM CDT Sat Oct 21 2017
.UPDATE...
Mostly cloudy conditions prevail over much of the region this
evening, with some shower activity ongoing across northwest
Mississippi. Temperatures are in the lower 70s, while winds are
out of the southeast. Slightly increased POPs to account for
latest radar trends and HRRR guidance through midnight. Otherwise
the forecast is on track at this time and requires no further
updates.
ZDM
&&
.PREV DISCUSSION... /issued 238 PM CDT Sat Oct 21 2017/
DISCUSSION...
Breezy and mild conditions this afternoon as pressures fall ahead
of the approaching front/upper trough in the Central Plains.
Temperatures this hour were in the upper 70s to low 80s...with a
few stations seeing dewpoints cresting 60F. Skies were a mix of
clouds and sun.
For tonight through Monday...models are in good agreement with a
faster solution for the shortwave trough in the Plains to briefly
become a closed low at 500mb in the Ozarks late tonight...then
sliding east into the Ohio Valley and quickly dampening by Monday
afternoon. Thus most Midsouth locations will see a window of
20-24 hours of precipitation...with points east of the
Mississippi River receiving upwards of 3 inches. A welcoming need.
The best instability with the associated cold front will be
confined to areas west of I-55 from roughly 10-18z tomorrow
morning...with the focus quickly shifting to points south of I-20
beyond this time. Moderate to heavier showers though will remain
well into the night across portions of west Tennessee and north
Mississippi. By Monday westerly surface winds will begin drying
the region...with brief break before the next wave and front
arrive on Tuesday. Only the far east may see lingering clouds and
a few isolated showers. The downsloping winds off the Ozarks
should raise temperatures to the low 70s in the west....while the
east stays in the 60s.
Tuesday through next weekend...models this period slowly begin to
diverge. Initially a second reinforcing cold front will slide
through the area with very little moisture left to work with.
Timing of this boundary on Tuesday may pose a tricky temperature
forecast. Behind the front northwesterly winds will make it
blustery across the north where 60F for a high may be a struggle.
Diminishing winds overnight will lead to the best chance during
the week for patchy frost to form in the east. Surface high
pressure will remain in control Wednesday and Thursday with winds
slowly becoming southerly. Highs will warm from the low to mid
60s...to the upper 60s to the mid 70s. Clouds will be on the
increase as the next shortwave and Canadian airmass drops into the
Upper Midwest by Friday. The axis position of this wave differs
considerably between the GFS and ECMWF...with the GFS farther
east...cooler and less precipitation. The mean ensemble members
show this trend as well. The Euro places a longer period of
southwesterly flow over the region and warmer temperatures. Have
leaned with the cooler and drier GFS.
JAB
&&
.AVIATION...
/00z TAFs/
A few thunderstorms continue to the SW of KCKM but should have no
impact on forecast terminals this evening. Generally benign
conditions are expected over the next 8-10 hrs although S to SE
winds will increase as the low-level jet intensifies. A line of
showers and thunderstorms will move from west to east across the
Mid-South early Sunday and VCTS was included at all TAF sites. In
addition to convection, MVFR (and potentially brief IFR)
conditions are expected across most of the area through at least
midday, if not well into the afternoon hours.
Johnson
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Miami FL
812 PM EDT Sat Oct 21 2017
.UPDATE...
Surface high pressure over the mid Atlantic will continue to
generate moderate to strong easterly flow over South Florida
tonight. Expect winds sustained generally between 10 to 15 mph
along the east coast metro region, increasing again by mid Sunday
morning. Latest NWS radar loop indicates light to occasional
moderate showers advecting onshore from the Atlantic. Instability
parameters still appear rather weak, so have not included any
mention of thunder in the update. Short term models, such as the
HRRR and WRF show isolated showers persisting through the night,
so have adjusted PoPs accordingly.
&&
.PREV DISCUSSION... /issued 405 PM EDT Sat Oct 21 2017/
DISCUSSION...
Latest WPC surface analysis shows a strong 1029 mb
cell of high pressure over the mid Atlantic region, with a weak
stationary boundary draped across the Bahamas. The combination of
these two feature has tightened the surface pressure gradient across
South Floria and increased easterly winds today. On average, winds
along the Atlantic coast have been sustained 20 to 30 mph, slightly
weaker inland. Satellite derived PWAT values are from 1.6"-1.7",
with a majority of the moisture located in the lower and upper
levels of the atmosphere. Weak instability has allowed for quick,
westward moving, light to moderate showers over the peninsula.
Not expecting any lightning with this activity, so have removed
mention from the latest forecast package. With little changing
synoptically tonight, expect gusty easterly winds to continue
along the east coast metro region, generally around 15 mph.
Sunday through mid next week: Models begin to slowly shift the
aforementioned surface high eastward towards the mid Atlantic
ocean. In response, flow will turn east southeasterly, then
eventually south southeasterly. Winds will remain breezy through
the period, especially along the east coast beaches and metro
regions. Mid range models prog a low pressure trough to deepen
over the Ohio valley, dragging a sharp cold front southward over the
Gulf. As this system begins to approach Florida late Monday,
moisture will begin to pool ahead of the front. The GFS forecast
PWATs increase to around 2.00" over our region. Intability
associated with the approaching front will also increase. Thus,
expect elevated chances for showers and thunderstorms Tuesday into
early Wednesday across the entire CWA.
Late into Friday: Behind the frontal passage, much drier and
cooler conditions will ensue. Maximum temperatures are forecast
only in the lower 80s on Wednesday, then struggle to reach 80
degrees on Thursday. Dry weather is expected, along with dewpoints
plummeting into the 40s and 50s. This front is a sure sign that
the end of the rainy season is near.
MARINE...
Pressure gradient between a decaying front over the region and
high pressure over the southeastern United States will bring east
wind of 20 to 25 knots and seas of 5 to 7 feet for much of the
waters through the weekend. A small craft advisory remains in
effect over the Atlantic waters and outer Gulf waters through
early Sunday morning.
AVIATION...
Scattered showers streaming westward across much of South Florida
should continue overnight. Activity has approached Naples more
than anticipated so added VCSH for KAPF from 20-0z. Easterly wind
gusts are likely to exceed 25 KT through sunset, then diminish
slightly overnight, before increasing again by mid-morning Sunday.
Shower chances drop off after daybreak Sunday, so for now have
left dry TAFs for FLL and Miami-Dade terminals. VFR should prevail
but periods of MVFR (mainly CIGs) quite possible, especially
through the afternoon.
BEACH FORECAST...
Persistent easterly flow will allow the high risk of rip currents
to persist through the weekend into early parts of the work week.
The flooding along the east coast during high tide should begin to
decrease over the next several cycles as the new moon phase ends.
&&
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 78 88 80 86 / 40 30 40 30
Fort Lauderdale 80 87 80 87 / 40 30 40 30
Miami 79 89 79 87 / 40 30 30 40
Naples 75 91 76 84 / 20 20 10 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Sunday evening for FLZ168-172-173.
AM...Small Craft Advisory until 6 AM EDT Sunday for AMZ650-651-670-
671.
GM...Small Craft Advisory until 6 AM EDT Sunday for GMZ676.
&&
UPDATE...27/JT
DISCUSSION...27/JT
MARINE...27/JT
AVIATION...17/AR
BEACH FORECAST...27/JT
Area Forecast Discussion
National Weather Service Melbourne FL
936 PM EDT Sat Oct 21 2017
.UPDATE...
It was rather quiet today as far rainfall with only isolated
showers producing trace amounts to only a few hundredths of an
inch of rainfall across the area. For the rest of tonight, drier
air mass will gradually erode as moisture is forecast to increase
from south to north in response to the lower-level winds turning
more southeasterly. Already beginning to see evidence of the
enhanced moisture with isolated showers developing across and just
offshore of Martin county. Both the HRRR and local WRF show
isolated to scattered shower activity gradually spreading
northward across the Treasure Coast into Brevard county through
the overnight. Inherited forecast in good shape with 40% PoPs
across southern Martin county with 30% continuing through the
Treasure Coast, Brevard, and coastal Volusia counties. Low
temperatures will be in the low 70s inland and mid 70s with a few
upper 70s possible along the coast.
&&
.AVIATION...
Mainly VFR. Drier air will gradually moisten with showers
expected to gradually increase along the coast from south to
north during the overnight. Interior terminals should expect
shower activity and perhaps a thunderstorm by late morning/early
afternoon on Sunday.
&&
.MARINE...
(previous discussion) Poor to hazardous boating
conditions will continue tonight with east winds 15-20 knots and
seas up to 7 feet. Winds begin to veer out of the SE Sunday then
more southerly Monday as high pressure ridge pushes seaward and a
strong cold front approaches from the west. Pressure gradient will
support wind speeds 13-18KT with seas 4FT near shore and 5-6FT
well offshore. Some increase in SW-W winds to near 20KT north of
the Cape Tuesday, however offshore component keeps seas no higher
than 4-5FT well offshore. Brief NW wind surge Tuesday night into
Wednesday will push seas up to around 7FT in the Gulf stream,
before they subside by Thu.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 73 85 73 86 / 20 50 40 50
MCO 72 88 72 87 / 10 50 20 50
MLB 78 87 76 86 / 30 50 30 40
VRB 77 87 75 86 / 30 50 30 40
LEE 71 88 72 86 / 10 50 20 50
SFB 71 87 73 87 / 10 50 20 50
ORL 72 88 73 88 / 10 50 20 50
FPR 77 86 75 86 / 30 40 30 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory until 10 AM EDT Sunday for Flagler Beach to
Volusia-Brevard County Line 20-60 nm-Sebastian Inlet to
Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter Inlet 20-
60 nm-Volusia-Brevard County Line to Sebastian Inlet 0-20
nm-Volusia-Brevard County Line to Sebastian Inlet 20-60 nm.
&&
$$
UPDATE/AVIATION...Combs
RADAR/IMPACT WX....Lascody
Area Forecast Discussion
National Weather Service San Angelo TX
814 PM CDT Sat Oct 21 2017
.UPDATE...
Severe thunderstorm watch number 505 now in effect through 2 AM
Sunday morning, for most of the Big Country and, the norther4n two
Heartland counties, and Runnels county. Just sent a new zone
forecast package to include a watch headline for those counties.
&&
.PREV DISCUSSION... /issued 647 PM CDT Sat Oct 21 2017/
AVIATION...
/00Z TAFS/
Look for VFR conditions to dominate through 00Z tomorrow, with
thunderstorms along and ahead of a cold front this evening and
later tonight. Expect the cold front at the Abilene terminal
around 05Z and at the San Angelo terminal about an hour later.
PREV DISCUSSION... /issued 313 PM CDT Sat Oct 21 2017/
SHORT TERM...
(Tonight and Sunday)
.Severe Storms Possible This evening...
An upper level trough and associated cold front will be the main
focus in the short term, with the potential for some severe storms
later this evening.
At the surface this afternoon, a cold front was moving south and
currently located across the southern Panhandle into northwest
Oklahoma. A diffuse dryline/surface trough extended south across the
eastern Low Rolling Plains and eastern Permain Basin. West Central
Texas was located in the warm sector with good low level southerly
flow. Also, good instability across the area with MLCAPES of
2500 J/KG. At the upper levels, a strong trough was located
across the central and southern Rockies, with large scale ascent
starting to increase across the Southern Plains.
Expect scattered to numerous thunderstorms across mainly northern
and eastern sections of West Central Texas tonight. The Hi Res
models(HRRR, Texas Tech WRF) indicate scattered storms developing
along the cold front and moving east across parts of the Big Country
this evening. More isolated storms are possible further south along
the dryline, mainly west of Sweetwater to San Angelo to Ozona line
for late this afternoon and early evening. The HRRR model is the
most aggressive with this possible development of convection. A few
storms may be severe this evening, mainly across the Big Country, as
vertical shear improves along with the instability. The main hazards
will be large hail, damaging winds and dangerous lightning. After
midnight, a line of storms are likely along the cold front across
the Heartland and Northwest Hill Country. A few strong storms are
still possible. For Sunday, expect a quiet forecast with gusty north
winds for a few hours. Highs will be in the 70s.
21
LONG TERM...
(Sunday night-Thursday)
Expect a roller coaster of temperature this week as two cold
fronts impact West Central Texas. The second cold front expected
later this week may be the strongest of the season. Mostly dry
weather is expected this week.
Temperatures rebound on Monday into the lower to mid 80s after
chilly morning lows in the 40s Sunday night. Then, a reinforcing
cool front and associated surface high builds into the region
Monday night. This will result in cool afternoon highs in the low
to mid 70s Tuesday with morning lows again in the 40s on
Wednesday. Afternoon highs climb into upper 70s Wednesday, and
into the mid and upper 80s by Thursday.
(Friday-Saturday)
The GFS is more similar to the ECMWF solution with respect to the
upper level and surface features. Both models now show an
amplified ridge building just off the the Pacific Northwest coast by
Friday. Models also prog a deep upper trough developing over the
middle of the country and extending south into Texas. This type of
upper flow should unleash the first Canadian front of this fall
season into Texas.
the two models show this front reaching West Central Texas by
Friday morning. Afternoon high temperatures next Friday and
Saturday may only reach the 60s. Morning lows on Saturday may drop
into the upper 30s to near 40. We`ll continue to monitor the
models as they continue to get a better handle on this potential
Canadian Cold frontal surge.
26
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 54 73 47 82 / 50 5 0 0
San Angelo 55 76 46 84 / 40 5 0 0
Junction 58 77 41 83 / 60 5 0 0
Brownwood 56 75 43 83 / 80 5 0 0
Sweetwater 53 73 50 81 / 20 5 0 0
Ozona 55 75 43 81 / 40 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$