Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/19/18
Area Forecast Discussion
National Weather Service Columbia SC
656 PM EST Sun Feb 18 2018
.SYNOPSIS...
A frontal boundary south of the forecast area will lift north
as a warm front tonight into Monday morning. Bermuda high
pressure will be in control Monday night through Thursday
bringing near record high temperatures. Another frontal boundary
may affect the area Friday.
&&
.NEAR TERM /THROUGH MONDAY/...
High pressure ridging into the Southeastern States from the
Mid-Atlantic coast will move further east tonight allowing the
low-level winds to turn more easterly promoting increasing
moisture across the area. It will also allow the front to the
south to begin slowly pushing back north as a warm front through
the night. Weak isentropic lift overnight will bring additional
cloud cover and isolated showers. However, the highest rain
chances will remain further off to the west and north through
the night. Will only have a slight chance to possible low chance
pops across the western and northern counties late tonight.
Fog may become an issue late tonight and towards morning with
the warm front moving through, and with the increase in low-
level moisture. However, the HRRR and RAP do not show any fog
and there is a 30 knot low level jet overnight, so have
continued to indicate only patchy fog development. Temperatures
will be well above normal overnight due to the front in the
area, cloud cover, and mixing. Lows in the lower to middle 50s.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
Monday and Monday night...frontal boundary will begin Monday
just north of the forecast area and slowly move northward away
from the area through Monday night. This will result in mostly
cloudy skies and patchy fog to start the day with the fog
burning off by mid morning. During the afternoon hours high
pressure will begin building into the region with the upper
level ridge also building over the eastern US. While the
southeasterly surface winds and southerly winds aloft will
transport moisture into the area the inversion will take time to
burn off resulting in stratus clouds persisting into the
afternoon hours and little time for diurnal heating to develop
cumulus clouds. As such expect mostly cloudy skies through
midday becoming partly cloudy during the afternoon. Monday night
the moisture will remain through the night and with a developing
inversion and light winds aloft expect fog to again develop
during the early morning and sunrise hours. Temperatures Monday
will range from the upper 60s over the northern and western
Midlands to the upper 70s in the southern CSRA...with overnight
lows in the middle to upper 50s.
Tuesday and Tuesday night...high pressure will continue building
into the region with southerly flow from the surface through the
mid levels. This will again keep Gulf moisture flowing into the
forecast area with the strong inversion taking through the
midday hours to again burn off. This will again result in mostly
cloudy skies during the morning with decreasing clouds through
the afternoon. Tuesday night a short wave will move northward
from the Gulf of Mexico through central GA and into Upstate SC.
This will keep the short wave just west of the forecast area
however there is potential for some showers mainly in the
northern CSRA and western Midlands Monday night. Temperatures
will be in the mid 70s to around 80 for afternoon highs with low
60s for overnight lows.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Models continue in good agreement with high pressure off the
coast of the Carolinas and an upper level ridge dominating the
region. A cold front will move toward the region Wednesday night
and Thursday then stall just west of the forecast area as the
high pressure and upper level ridge push the system northward.
The front will move northward Thursday night through early
Saturday with the next front approaching Saturday night and
Sunday. Have taken a cautious approach for Saturday night and
Sunday as the GFS remains more progressive while the ECMWF again
keeps the front just to the northwest of the area. Temperatures
through the long term will be well above normal.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Frontal boundary across central and east Ga will move north into
the region overnight. Ceilings are lowering to MVFR in the CSRA
and southeast Midlands this evening. The models indicate
ceiling will lower overnight to IFR or LIFR conditions late
tonight into Monday morning as warm front moves into the area.
Highest chance of LIFR appears to be near AGS and OGB. As the
front moves possibly to the north of the terminals Monday
afternoon, expect ceilings to improve to MVFR and winds to shift
to southeast or south 5 to 10 knots.
EXTENDED AVIATION OUTLOOK...Chance of showers/restrictions
through Wednesday associated with onshore flow, isentropic lift,
and then another approaching cold front.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Dodge City KS
822 PM CST Sun Feb 18 2018
.SYNOPSIS...
Issued at 544 PM CST Sun Feb 18 2018
A dry cold front will sag south tonight into Monday, and then
stall out over SW Kansas Monday afternoon. A very large
temperature difference is expected Monday afternoon, with northern
counties below freezing, and areas along the Oklahoma border in
the 70s. The cold air will win the battle, with much colder
temperatures Tuesday and Wednesday. Expect moderating temperatures
Thursday and Friday. Dry weather will continue.
&&
.UPDATE...
Issued at 822 PM CST Sun Feb 18 2018
Cold front making excellent progress through NE Colorado,
with temperatures crashing quickly behind it (Cheyenne fell from
53 to 26 in one hour). Given the front`s momentum on satellite
imagery and these observations, updated Monday`s temperatures by
dropping them significantly (especially north of US 50). 00z NAM
and latest HRRR runs show the frontal boundary clearing the KS/OK
border now by 9 am, and indications are the cold air will win out.
Strong cyclogenesis is still expected in SE Colorado Monday
afternoon, and the boundary will likely still stall and retreat
northward. Some wild temperature differences and temperature
swings are likely across the southern counties during the day
tomorrow. But north of US 50, it looks like the cold air will
reign supreme.
UPDATE Issued at 533 PM CST Sun Feb 18 2018
Added areas of smoke to the Barber county vicinity, as smoke plume
from fire in NW Oklahoma (Woods county) continues to spread NE.
&&
.SHORT TERM...(This evening through Monday)
Issued at 311 PM CST Sun Feb 18 2018
Temperatures are a real challenge in the short term with a sharp
baroclinic zone becoming established in western Kansas Monday and
uncertainty about how much if any the shallow cold air will mix
out during the day Monday.
A cold front extended from eastern South Dakota across central
Nebraska to eastern Wyoming early this afternoon with pressure
rises of two to three millibars in three hours behind the front in
South Dakota and northern Nebraska behind an upper level trough
that was moving from eastern North Dakota into Manitoba. A deep
surface cyclone was centered in southeast Wyoming and northeast
Colorado. A sharp pressure gradient across Kansas was producing
howling south to southwest winds with frequent gusts to near 50
mph. Relative humidities were below 15% only in west central
Kansas, but the dry air should spread farther east by late
afternoon.
An upper level vorticity maximum evident on satellite imagery off
the southwest British Columbia coast will continue to dig into
the mean long wave trough position in the western United States,
and the upper level flow over the central United States will back
tonight and Monday. A weak upper level trough that extended from
Wyoming to northeast New Mexico will continue moving northeast
tonight, and a weak surface cyclone will ripple along the low
level baroclinic zone. The cold front will progress southward into
northern Kansas this evening in the wake of the weak cyclone and
should reach southern Kansas by morning. Temperatures tonight will
be mild for this time of the year with lows in the 40s and lower
50s across southern Kansas in advance of the cold front.
Temperatures likely will fall into the upper 20s behind the front
in northern Kansas.
The models are reasonably consistent in slowing the front to a
stop north of the Oklahoma border as cyclogenesis occurs in
Colorado as an upper level trough ejects from the long wave
position into eastern Colorado by Tuesday morning. Model soundings
suggest that stratus will develop north of the front but may
erode northward Monday afternoon. It usually is hard to erode cold
air once it is in place, but there is good consensus among the
model solutions that at least some erosion will occur. The air
behind the front is not true arctic air, and there should be quite
a bit of sun for some distance on the cold side of the front.
There will be a very substantial temperature gradient Monday with
temperatures holding in the lower 30s around Interstate 70 and
rising into the 70s south of the front.
.LONG TERM...(Monday night through Sunday)
Issued at 311 PM CST Sun Feb 18 2018
A long wave trough will persist in the western United States with
a strong upper level ridge from the Gulf of Mexico across Florida
to the western Atlantic Ocean. Minor upper level troughs will
move around the mean long wave position and lift out across the
central part of the country. Although the potential for beneficial
precipitation on southwest Kansas through the end of February is
minimal, there will be several opportunities for light
precipitation.
The upper level trough that will extend from the Dakotas into
eastern Colorado Tuesday morning will lift out to the northeast
and should extend from James Bay to Minnesota by Wednesday
morning. There may be enough isentropic lifting over the front to
produce light precipitation in south central Kansas Monday night.
The phase of the precipitation is not certain, but most of it
should fall before surface temperatures drop below freezing. Cold
air will surge southward across the Plains Monday night and
Tuesday, and temperatures Tuesday will vary from the 20s in
northern Kansas to near 50 along the Oklahoma border.
Another minor upper level trough will approach Wednesday, and
isentropic lifting over the cold air mass may produce some light
precipitation in central and southern Kansas. Temperatures will be
below freezing at the surface, and a warm layer aloft will
support the possibility of freezing rain or sleet. Yet another
upper level trough will approach Thursday and will provide an
opportunity for light precipitation.
A stronger upper level trough should reach Kansas about Saturday.
Warm air advection will occur Friday as a surface cyclone
develops in southeast Colorado, and temperatures should be above
freezing by the time precipitation develops Friday night and
Saturday. However, details in timing of the minor upper level
troughs and the thermal structure of the low levels of the
atmosphere are uncertain.
It still appears likely that the deep upper level low will weaken
and retrograde to the Canadian Arctic in early March and that an
area of high pressure will spread from northern Europe into
eastern Canada. A mean upper level trough is likely to persist in
the western United States, so chances for precipitation will
continue into early March.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 500 PM CST Sun Feb 18 2018
Very strong SW winds will diminish some around sunset, but remain
gusty through the evening hours. The low level jet will
reintensify quickly this evening, so maintained a mention of LLWS
at all airports through 06z Mon.
Starting around 06z Mon, a dry cold front will sag southward
across SW Kansas, accompanied by a shift to north winds. Cold
front should arrive at HYS by 06z Mon, and DDC/GCK by 09z. The
frontal boundary is expected to stall on Monday, and is forecast
to remain north of LBL. As such, kept prevailing S/SW winds at
LBL through Monday. There is potential for post-frontal stratus
behind the boundary, but model agreement on this is poor,
resulting in low confidence. NAM forecast soundings are very
aggressive with IFR stratus cigs impacting at least DDC/HYS
through Monday morning, and this guidance was followed in this TAF
issuance. TAF amendments are likely through Monday as this
boundary and stratus edge into SW Kansas.
&&
.FIRE WEATHER...
Issued at 333 AM CST Sun Feb 18 2018
Strong south to southwest winds will continue this afternoon into
the evening. Very dry air in west central Kansas will spread
slightly farther to the east, but relative humidities will not
fall below 20 percent east of a line from Hays to Liberal. The Red
Flag warning will be continued given the extremely dry fuels and
high winds even though relative humidity criteria will not be met.
Warm temperatures and gusty southwest winds near the Oklahoma
border will support active fire behavior Monday, but relative
humidities will remain above thresholds for fire weather
headlines.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 44 45 27 36 / 0 0 10 0
GCK 33 40 20 31 / 0 0 10 0
EHA 46 74 28 40 / 0 0 10 0
LBL 49 68 32 43 / 0 0 10 0
HYS 30 34 18 26 / 0 10 20 0
P28 53 66 37 46 / 0 10 30 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Turner
SYNOPSIS...Turner
SHORT TERM...Ruthi
LONG TERM...Ruthi
AVIATION...Turner
FIRE WEATHER...Ruthi
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
826 PM CST Sun Feb 18 2018
.UPDATE...
There is a pulse of energy moving across the northeast part of Mexico
this evening. IR satellite images show an increase on cloud top
temperatures as the cluster of thunderstorms move over the high
Mexican terrain. Both HRRR and the 3km WRF Texas Tech models pick up
on this feature and brings it across the Rio Grande Plains including
the Del Rio area around 11 PM late this evening through 1 AM Monday.
If the cluster of storms holds and move over Del Rio and vicinity,
expect heavy rain and thunderstorm wind gusts of 30 mph or so. As the
cluster of storms move into the Edwards Plateau, there will be less
instability in place and only showers are expected to continue moving
into the Hill Country overnight.
&&
.PREV DISCUSSION... /ISSUED 537 PM CST Sun Feb 18 2018/
AVIATION...
VFR conditions prevail at all sites but conditions will deteriorate
back to IFR/LIFR overnight. In addition, the latest runs of the HRRR
and TTU WRF show a complex of showers and thunderstorms developing
west of the Rio Grande late this evening and moving east into the CWA
around 5-6z. Will watch the trends of this closely and will mention
VCSH in the DRT TAF from 5-9z for now and amend as necessary. If this
complex were to develop, weakening showers could be possible for the
I-35 sites around daybreak. MVFR/VFR conditions will be slow to
arrive tomorrow afternoon and will likely only see a few hour
reprieve into VFR before IFR conditions return tomorrow evening.
Otherwise, southerly flow will be breezy tomorrow around 15 knots.
PREV DISCUSSION... /ISSUED 317 PM CST Sun Feb 18 2018/
SHORT TERM (Tonight through Monday Night)...
An area of scattered showers and isolated thunderstorms this morning
has moved off to the northeast as forecast leaving much of the CWA
dry today. There still exists a few weak echoes on radar as of 2PM
this afternoon associated with isentropic ascent in the lowest 100
mb.
After this moves out late this afternoon and evening, another
overnight of low cloud development looks likely. Latest runs of the
HRRR also indicate another weak disturbance generating some light
shower activity near Del Rio and shifting east overnight. This, plus
the potential for some light drizzle, warrants at least slight chance
PoPs in the forecast. The maintained isentropic ascent through the
day tomorrow will also keep skies cloudy and PoPs non-zero.
LONG TERM (Tuesday through Sunday)...
Models have continued to show a consistent signal for our first good
rainfall event beginning as early as late Monday evening and
persisting through at least Wednesday. WPC guidance for QPF continues
to highlight an area near TexArKana and by all indications at this
point, that still looks very good.
The thinking continues that initial convection could begin near Del
Rio and west as 925-850mb confluence aligns with the right entrance
region of a developing UL jet and quasi-dry line west of Val Verde
county. This alone will be enough to likely develop at least
elevated showers and storm potential, but the kicker will be
instability to allow these to become strong. Looking at forecast
soundings from the NAM/GFS for 00Z Tuesday, there is quite a stubborn
cap at 850 mb whereas the GFS is uncapped. This will obviously play
quite a role in whether hail or wind potential will be associated
with the storm development. It will likely also play a role in the
evolution of this system throughout the overnight period as these
features shift eastward. Currently, the thinking is this cap will
indeed hold with the extensive cloud cover likely around due to the
persistent isentropic ascent throughout the day Monday. Thus while
some storms could produce some small hail, the bigger focus will be
as this system progresses eastward and organizes.
As these features shift eastward overnight, a quasi-liner system will
likely progress across the Plateau towards the I-35 corridor. As this
occurs, PWATs will steadily increase to about 1.5+" by mid day
Tuesday according to the GFS. The dry line surges eastward in
response to a cold front diving south across the Red River Valley.
Additionally, another piece of UL energy comes across the Mexican
mountains and provides enhanced lifting parallel to the dry line and
advancing cold front. The more favorable convergence along the front,
additional UL support, and continued strong moisture flux Wednesday
morning should re-invigorate the line of rainfall and its at this
time that heavy rainfall potential will likely be maximized. QPF
values are still generally manageable, with even the highest
perturbations staying below 3 inches storm total. Thus, the previous
forecast`s mention of 1-2 isolated 3 to 4 inches still looks fair.
The variable with the least certainty is instability. There are some
indications that as much as 500-1000j/kg of SBCAPE may be present per
the KAUS proximity sounding (NAM/GFS). Not sure if this is
believable given the presence of shower activity, extensive cloud
cover, the potential for outflow should the linear system become more
organized, and any other unforeseeable mesoscale features, but IF
so, these QPF values would likely need to be raised. For now, there`s
just not enough certainty to up the forecast values beyond the
previous forecast.
After this system moves east and the cold front pushes through, this
should at least briefly cease rainfall potential overnight Wednesday
night, but overrunning appears agreed upon in the medium range models
and thus cloud cover and PoPs quickly return, much like the
conditions we have seen over the last several days.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 64 74 65 72 59 / 20 20 50 80 90
Austin Bergstrom Intl Airport 63 74 65 73 60 / 20 20 40 80 90
New Braunfels Muni Airport 63 75 65 73 61 / 10 20 40 80 90
Burnet Muni Airport 62 73 64 71 53 / 20 20 70 80 90
Del Rio Intl Airport 64 80 62 79 58 / 40 20 60 20 50
Georgetown Muni Airport 63 74 65 71 55 / 20 20 50 80 90
Hondo Muni Airport 64 80 66 77 61 / 20 20 50 60 80
San Marcos Muni Airport 63 75 65 73 60 / 20 20 40 80 90
La Grange - Fayette Regional 65 75 67 75 64 / 10 20 20 70 80
San Antonio Intl Airport 64 77 66 75 62 / 10 20 40 70 90
Stinson Muni Airport 64 78 66 76 63 / 10 20 40 70 80
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Hampshire
Synoptic/Grids...17
Public Service/Data Collection...33
Area Forecast Discussion
National Weather Service Hastings NE
547 PM CST Sun Feb 18 2018
.SHORT TERM...(This evening through Monday)
Issued at 256 PM CST Sun Feb 18 2018
Winds today will decrease late this afternoon and this evening from
northwest to southeast. This will occur ahead of a cold front that
will move through tonight...shifting winds back to the north.
The main concern for the overnight hours is freezing drizzle. As of
now, the HRRR/RAP are a good middle ground between the aggressive
NAM and the less aggressive GFS. One thing of note is that the
ESRL runs of the RAP and HRRR show significantly less
precipitation than the operational runs. Nevertheless, the most
favored areas for freezing drizzle will be north and east of a
line from Ravenna, to Hastings to Superior. Looking closer at HRRR
forecast soundings, we could even see some light sleet briefly mix
in as temperatures in the lowest 1000` continue to drop. Drizzle
is still expected to end 6-9AM as drier air advects in. I don`t
plan on making any changes to the winter weather advisory, but the
evening and mid shifts will need to keep a close eye on short-
term trends.
After a cold day on Monday, models indicate another round of wintry
mix developing Monday night on an area of lift ahead of a deep
trough approaching the area. Based on NAM/GFS, the model blend may
be bringing in too much precip too early. Our forecast area will be
caught in the middle between frontal precip to our southeast and the
better lift across the sandhills.
Unsurprisingly, the NAM shows a band of strong 700-500mb
frontogenesis developing across the sandhills, and develops a band
of heavier snow in that area. What is more interesting is that some
of the other mesoscale models (mainly the NCEP WRF-ARW and RGEM)
develop this band of snow much closer to, or even in, our
forecast area. As a result, the model consensus has increased the
snowfall for western parts of the forecast area.
.LONG TERM...(Monday night through Sunday)
Issued at 256 PM CST Sun Feb 18 2018
Any lingering precipitation should wind down Tuesday morning, and
clearing skies may allow wind chills to dip into the -10 to
-15 degree range through mid-morning. Tuesday is expected to be
the coldest day of the week with high temperatures struggling to
reach much higher than the teens for most of the area. Tuesday
night will likely also be the coldest night of the week with lows
generally ranging from -5 to 5 degrees. Winds won`t be as strong,
but we could still see widespread windchill values in the -10 to
-20 degree range.
Forecast temperatures for the rest of the week have trended downward
slightly. Highs are only expected to reach the 20s/30s on
Wednesday/Thursday before another system moves through the late
Thursday through Friday. There is considerable uncertainty
regarding the details of the next system, but it does appear that
we will have multiple rounds of precipitation...possibly one late
Thursday into early Friday and another Friday night into Saturday.
This also appears to be a "warmer" system with high temperatures
above freezing each day, so we will likely have multiple
precipitation types to contend with as well.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 534 PM CST Sun Feb 18 2018
A fast approaching cold front will bring a shift in winds over the
next hour or two as it rapidly tracks southward across the region.
Already have seen this wind shift affect ODX...and expect it to
reach both KGRI and KEAR around 19/01Z with gusty northerly winds.
While initially conditions will remain VFR...expect MVFR stratus
to reach the terminals around midnight...with some very light
drizzle possible. Once settling in...do not expect the stratus to
go anywhere through the remainder of the period...with winds gust
increasing to near 30KTs overnight and then persisting through the
mid afternoon hours tomorrow.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory from 3 AM to 9 AM CST Monday for NEZ063-
064-076-077.
Winter Weather Advisory from midnight tonight to 9 AM CST Monday
for NEZ041-048-049.
KS...Red Flag Warning until 7 PM CST this evening for KSZ005-017-018.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Rossi
Area Forecast Discussion
National Weather Service Wichita KS
845 PM CST Sun Feb 18 2018
.SYNOPSIS...
Issued at 229 PM CST Sun Feb 18 2018
A wave is positioned along the Front Range with the
increasing gradient which combined with mixing has brought windy
conditions for Kansas. Wind gusts have been from 40 to even 55 mph
with the highest gusts in Russell County. Temperatures have climbed
into the lower 50s to lower 60s. The Red Flag Warning and Wind
Advisory remain in effect until 6PM.
&&
.UPDATE...
Issued at 844 PM CST Sun Feb 18 2018
Robust warm advection continues to lead to lots of low level
moisture streaming to the north. Latest RAP shows this moisture
transport and advection continuing for the late evening hours and
overnight. Already seeing increased mid level clouds in response to
the advection across wrn OK at this time. As this moisture advection
lifts NE overnight, think a few showers will develop for areas east
of the KS Turnpike after midnight, as isentropic lift also
increases. MUCAPE also increases to around 1000 j/kg which could
also lead to a few embedded thunderstorms. Increasing pops for SE KS
look on track, with a mention of showers and some isolated
thunderstorms. Do not plan on any major changes to the grids/zones
at this time. Certainly think that SE KS will see widely scattered
showers and a few storms by sunrise Mon morning.
Ketcham
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 229 PM CST Sun Feb 18 2018
Forecast challenges and highlights: Precipitation chances for this
evening into the first part of the week and high temperatures on
Monday as well as Tuesday
A trough is moving onshore while a wave along the Front Range is
going to have a portion of it head to the northeast. This will
create an axis from northeast to southwest. The system is slow
moving as much of the trough apparently wants to hang out over the
Rockies. As the axis sits in place, there is increasing moisture
advecting moving into the Southern Plains. Chances of precipitation
may move in beginning tonight with the movement of the wave. Models
differ in the extent of the precipitation for tonight into
Monday. The highlighted area is still in the southeast corner of
the Sunflower State, southern Missouri and eastern Oklahoma.
Warm air advection is ramped up for Monday with a piece of cold
air advection on the back side of the wave across northwest Kansas
into Nebraska. High temperatures for the start of the work week
were a challenge as the southeast advance of the cold air could
creep into central Kansas. Discrepancies exist in the models with
some going much cooler and others keeping the values higher. There
will definitely be a cool down, but it is hard to say how much
that will be.
Chances of precipitation increase for Missouri into eastern
Oklahoma with a highlight over southeast Kansas of our county
warning area. Thunderstorm activity has a higher likelihood on
Monday afternoon and evening. It is possible that there could be
an isolated stronger wind gust of 40 to 50 mph or small hail, but
heavy rain is more likely. Anticipated precipitation will
certainly help the moderate and severe drought conditions for that
area. Moisture is certainly going to be welcomed with open arms.
Accumulations continue to range from a half of an inch to two
inches with the highest values in the southeast corner of the
state. Higher amounts are expected in the Ozarks. Across central
Kansas, the profile column indicates low level moisture that would
suggest freezing drizzle versus freezing rain on Monday night
into Tuesday.
As the trough finally shifts out of the area, an advance of cold
air will occur on Tuesday. On Wednesday morning, the drop in
temperatures to the single digits for central Kansas calculate
wind chills below zero. Surface high pressure comes in on
Wednesday, and high temperatures will only top out in the lower
30s. A mixed type is currently anticipated with the latest blend
of the models for Wednesday for the entire area.
.LONG TERM...(Thursday through Sunday)
Issued at 229 PM CST Sun Feb 18 2018
A weak wave is showing up to move across on Thursday with the more
pronounced feature not until Saturday. Chances of precipitation
remain in the forecast for most of the extended forecast. The
temperatures aloft vary between models and beg the question of the
precipitation type. On Thursday night into early Friday morning
the focus for a mixed phase of rain and freezing rain is
anticipated in central and parts of south central Kansas. It is
possible that it could be snow instead of freezing rain, but the
potential for warmer air to be in place is what is hinting the
liquid variety. Accumulations are not expected at this time. Given
the differences in the models and latter part of the forecast,
changes will occur. Stay tuned for updates. A gradual warming
trend is in store for the end of the week. Weekend temperatures
are expected to rise back into the 50s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 604 PM CST Sun Feb 18 2018
Increasing low level moisture advection will lead to low clouds
continuing to increase across south central and southeast KS. Still
expect KICT to be on the western edge of MVFR ceilings as they
eventually move into southeast KS(KCNU). Should see another round of
low level wind shear this evening as low level jet remains rather
strong. The low clouds will become more expansive tonight as low
level moisture continues to funnel into the region. Currently have
high confidence that IFR ceilings will impact areas along and SE of
the KS Turnpike tonight into Mon morning. A cold front is still
expected to move into central KS on Mon morning, reaching KICT
around 18z. This will shift winds around to the north and diminish
IFR ceilings.
Increasing low level moisture will also lead to the chance of
showers and possibly some thunderstorms increasing near the KCNU taf
site by around 06z/Mon. So will add this mention to the KCNU taf
site.
Ketcham
&&
.FIRE WEATHER...
Issued at 229 PM CST Sun Feb 18 2018
After the extreme grassland fire danger today, Monday is the only
day with very high grassland fire danger indicated for much of the
forecast area. The main concern is going to be in the morning for
central and south central with the stronger winds. Southeast Kansas
will have very high conditions for all of Monday with sustained wind
speeds of 20 to 25 mph. There are chances of precipitation for much
of the rest of the forecast with the best chances across southeast
Kansas on Monday night into Tuesday. Thunderstorms are possible
with this activity.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 52 67 41 46 / 10 30 70 60
Hutchinson 50 59 33 38 / 10 20 50 30
Newton 50 61 36 39 / 20 30 70 50
ElDorado 52 66 43 49 / 20 40 80 80
Winfield-KWLD 52 71 52 56 / 20 30 70 80
Russell 32 42 20 28 / 10 10 20 10
Great Bend 39 47 22 31 / 10 10 20 10
Salina 46 47 26 33 / 20 20 50 20
McPherson 48 55 30 36 / 10 20 50 30
Coffeyville 54 71 59 64 / 60 70 80 90
Chanute 52 68 55 61 / 50 60 80 90
Iola 52 66 54 58 / 50 70 80 90
Parsons-KPPF 52 70 58 62 / 60 60 80 90
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Ketcham
SYNOPSIS...VJP
SHORT TERM...VJP
LONG TERM...VJP
AVIATION...Ketcham
FIRE WEATHER...VJP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
850 PM CST Sun Feb 18 2018
.UPDATE...
850 PM CST
GOES-16 differential water vapor RGB this evening shows shortwave
trough over the central plains embedded within the broad mid-upper
level moisture plume associated with the subtropical jet. The 00z
evening upper air analysis showed a significant moisture gradient
at 850mb between bone dry air mass sampled at KILX/KDVN and
seasonably moist air mass at KSGF/KTOP. Evening RAOBs already were
sampling 50 to nearly 60kt southwesterly flow around 850mb with
KDVN WSR-88d showing a 10-15kt increase in low level flow in the
past 3 hours. This very strong low level jet should transport the
more moist air mass upstream rapidly northward tonight above sharp
frontal inversion. This supports the high-res model solutions
which show convective precip blossoming over eastern IA/western IL
later this evening. Anticipating showers and isolated t-storms to
quickly develop toward or just after midnight to our west before
spreading east across mainly the southern half of our CWA
overnight into early Monday morning.
At the surface, moderately strong and occasionally gusty southerly
winds should result in near steady temps through the night. The
higher dewpoints are still well south toward the Missouri Ozarks
region, but should begin to surge northward tonight with warm
frontogenesis over central IL later tonight. As the low level
moisture begins to impinge on the snow covered areas of northern
IL and northwest IN believe that dense fog will become an
increasing threat, particularly after sunrise Monday morning and
lingering into the afternoon north of the northward advancing warm
front. As warm front lifts north, look for a quick improvement in
visibilities, but there is still some uncertainty how much/if at
all, the snow cover will impede the warm front`s northward advance
Monday. The NAM gives snow pack apparent super powers and it is
likely too cool with temps and slow with the FROPA, with a
compromise solution between the NAM and RAP probably most
reasonable at this point.
Strongly considered issuing a dense fog advisory for tomorrow, but
fog can be fickle and have been burnt before with apparent slam
dunk fog events, so opted to "message" the dense fog in a
graphical nowcast and will let later shift issue the NPW.
Flood watch looks on target and no changes made this evening.
Updated grids have been saved and will be firing out a new ZFP and
LFP shortly.
- Izzi
&&
.SHORT TERM...
202 PM CST
Through Monday...
Temperatures this afternoon will depend on cirrus overhead. Locations
that see breaks in the cirrus should see temperatures rise into
the 40s. Locations that don`t see breaks will stay in the 30s.
Winds will also be strongest where sunshine can get mixing going.
The main focus for this period is when rain will start Monday,
how far north the warm front will get, and thunder chances. Low
pressure will take shape over the High Plains tonight and reach
the mid Mississippi Valley mid Monday afternoon. Rainfall will
spread south to north. Areas along and south of I-80 should see
rain before 6AM. Forecast soundings feature a bit of elevated CAPE
and a very stout cap. I think the cap will limit showers from
tapping into the CAPE, so I do not have any thunder mentioned
prior to 6AM.
The GFS and ECMWF lift the warm front north into southern WI,
while the NAM stalls the front near I-88. The NAM has a slower
progression of rain to the north, but all of the forecast area
should see moderate rain showers by Monday afternoon. Embedded
thunderstorms are possible, especially in the afternoon as the
warm front lifts and the low`s center reaches the region. Severe
storms are not expected, but increased rainfall rates could lead
to localized flooding especially with the snowpack.
Dewpoints will soar into the 50s, and areas of fog are likely
late tonight through Monday afternoon, especially if the warm
front stalls over northern IL.
JEE
&&
.LONG TERM...
202 PM CST
Monday night through Sunday...
Flooding is the main long term concern. As mentioned
in previous discussions, precipitable water (the amount of
available moisture in the atmosphere) values, and moisture
transport (the movement of moisture into our region) are forecast
to reach the maximum values ever reached in the month of February
per ILX/DVN sounding climatology. Rivers and small streams will
have sharp responses and flood prone areas should be alert in the
coming days. A flood watch will be issued for the entire area
given some uncertainty in the location of highest impacts, but at
this time we are focusing on the Tuesday into early Wednesday time
frame.
Current forecasts have the Kankakee River at Shelby getting close
to major flood stage from the combination of snowmelt (we have
0.85" of liquid here in Romeoville in the snowpack), seasonally
frozen ground limiting absorption of moisture, and the heavy rain.
While the axis of heavy rain is not always nailed down at this
distance and does shift some, the signal is high for a few
periods/areas of concern at different times.
The issue out of the gate Monday night is the position of the warm
front that the global models surge through the area during the
day, while the NAM (possibly catching onto the snowpack in place)
keeps the front locked across I-80/I-88 and does not lift it
through until late Monday night. These uncertainties will affect
the position of highest QPF Monday night.
In spite of these uncertainties, meteorologically the setup is
very favorable for flooding concerns in the region, especially
on/near rivers and streams. High pressure will be positioned
across the southeast United States, with a digging neutrally
tilted upper trough over the western U.S.A. Deep southwest flow
ahead of the trough will allow gulf moisture to be advected due
north into our region. Sometimes we get robbed of some of this
moisture due to convection to our south, but it appears we will
not have a problem getting it up here. With a cold front slowing
shifting southeastward into the region, the upper level jet will
strengthen and enable not only a prolonged period of upper level
lift, but will also allow several low pressure waves to ride along
the front and keep it stationary. While the initial concern will
be over the Rock River Basin area (north central Illinois - I.E.
Rockford area, I-88 Northward west of Chicago), the GEFS ensembles
gradually shift this axis to Chicago Tuesday and along the
Kankakee/Iroquois basins (east central Illinois/Northwest Indiana)
later Tuesday and Tuesday night.
These subtle shifts of the heaviest axis are helpful to
reduce flooding, but am increasingly concerned with the response
on Tuesday after snow has melted and then throw a bunch of rain on
top that, plus the fact the GEFS ensembles are indicating several
6 hr periods of probabilities of greater than 0.6" of QPF in 6
hours (which is a high number for an ensemble, deterministic
models and the real atmosphere can produce much more). Areas
across Chicago southeastward appear like they have the highest
potential for more prolonged rainfall as the upper jet
strengthens, the front stalls some, storm motion values decrease
significantly, and precipitable water values increase further
Tuesday/Tuesday evening.
While the main heavy rain axis will shift southeast of the area
Wednesday as high pressure is forecast on all guidance to shift
from the upper Midwest into Wisconsin and push the main cold front
into Indiana, we remain in strong southwest flow aloft such that
there could be some additional rain along and southeast of I-57
into Wednesday, and if the precip gets hung up farther northwest
into the colder air, there is lower threat of some wintry precip
on the back side both Tuesday night and Weds.
Regarding thunderstorms and severe weather potential...Forecast
soundings feature very little instability across northeast Illinois
and northwest Indiana. The profiles do show deep enough moisture
for charge separation, thus chance of thunder (and enhancing
rainfall rates) are warranted. Severe weather chances while not
zero given the shear profiles, are not very high in this setup.
There is a low probability if some surface based cape can be
realized ahead of the cold front Tuesday afternoon.
Beyond this time, we do still stay in active southwest flow aloft,
which will likely bring waves of precip later in the week, but the
main frontal boundary appears to remain south of the area which
will keep the heavier rain focused across the Ohio and Tennessee
River valleys.
KMD
&&
.HYDROLOGY...
202 PM CST
The combination of snowmelt (we have 0.85" of liquid here in
Romeoville in the snowpack), seasonally frozen ground limiting
absorption of moisture, and heavy rain, expect sharp rises over
area rivers and streams in the next few days. Most areas will see
at least an inch of rain, with 2 to 4 inches possible in some
locations. Expect several rivers to get into flood, and numerous
rivers to get above bankfull. Ice jam breakup may also contribute
to flooding in the coming days. While the axis of heavy rain is
not always nailed down at this distance and does shift some, the
signal is high for flooding concerns. Current forecasts have the
Kankakee River at Shelby getting close to major flood stage.
KMD
&&
.AVIATION...
For the 00Z TAFs...
553 pm...Several forecast concerns this period including cigs/vis
Monday...periods of showers Monday...chance of thunderstorms
Monday afternoon/evening...low level wind shear this evening and
again Monday evening.
South/southeast winds will remain gusty this evening into the
20-25kt range. Speeds will slowly diminish overnight as winds turn
more southerly. Speeds will diminish further Monday morning as
wind directions turn back southeasterly. A warm front will move
across the area Monday afternoon...turning winds back to the
south/southwest with speeds/gusts increasing. Low level wind shear
in the 45-50kt range is expected this evening and then again
Monday afternoon into Monday evening and may need to be included
for this time period with later forecasts.
Much warmer and moist air will spread over the region Monday
morning with cigs/vis steadily lowering. While there still remains
uncertainty regarding how low visibilities will drop...trends are
suggesting vis will lower under 1sm everywhere Monday morning with
dense fog possible. Have continued the trend down with tempo 1/2sm
with tempo 1/4sm at rfd. Its possible these may become prevailing
vis for a time midday. As the warm front lifts north in the
afternoon...vis will improve and possibly more so than currently
advertised. While some improvement in cigs are possible with the
warm front passage...confidence is low regarding cig improvement.
Showers are expected to develop south of the terminals early
Monday morning and continue through late morning and there could
also be some thunderstorms. An isolated shower is possible over
the terminals...but confidence is low enough to keep them dry
through about sunrise and there could still be some periods
without showers Monday morning...though the low cigs/vis may allow
drizzle to develop. A steadier rain is expected Monday afternoon
into Monday evening which may also aid with improved visibilities.
This is also the time period for the best chance of any isolated
thunderstorms for the terminals...but confidence is still too low
for even prob mention with this forecast. cms
&&
.MARINE...
202 PM CST
South winds will still ramp up a bit late this afternoon
and evening in the stronger pressure falls ahead of low pressure
across the upper Midwest. Some of this may be mitigated by an area
of low clouds and fog over the water. The stronger winds are
favored over the northern half of the lake, though the nearshore
waters will still see some gusts to 25 to 30 kt too. Winds will
weaken overnight as the low weakens and moves into Ontario.
A cold front trailing from the low will settle half way down the
lake by early Monday, before another low pressure wave translates
along the boundary from the Central Plains to the south half of
the Lake by Monday evening. This will result in northerly winds
across northern Lake Michigan north of the front, and south winds
to it`s south. Another surface low will ripple along the front
along roughly the same track Tuesday, before the front eventually
drifts south of the Lake Tuesday night. Northerly winds will
affect the entire lake by that time, as strong high pressure
builds in from the west. Despite the varying winds, the low
pressure systems are not that strong and therefore winds will
remain below gale concerns. High pressure will keep concerns low
over the lake beyond this time.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Flood Watch...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039...6 PM Monday to 6 AM Wednesday.
IN...Flood Watch...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM Monday
to 6 AM Wednesday.
LM...Small Craft Advisory...nearshore waters
until 3 AM Monday.
Gale Warning...LMZ777-LMZ779 until midnight Monday.
&&
$$
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Area Forecast Discussion
National Weather Service Midland/Odessa TX
531 PM CST Sun Feb 18 2018
.DISCUSSION...
See aviation discussion below.
&&
.AVIATION...
Radar show a few storms passing just s of MAF with SHRA to the sw,
we opted to keep TS out of the TAFMAF based on movement. There is
the possibility of redevelopment later this evening and again
toward morning. Otherwise windy conditions will persist at MAF,
FST, HOB until around 06Z, then increase again around 18Z Mon.
&&
.PREV DISCUSSION... /issued 250 PM CST Sun Feb 18 2018/
DISCUSSION...
South winds are bringing moisture into West Texas and increasing
low level instability. Some evidence of this can be seen west of
the Pecos River where heating and orographics are causing a field
of cumulus to develop. However there is a cap in place and with
no trigger farther east other than weak afternoon heating, it
will be difficult for deep convection to form. The HRRR has been
showing a lone storm forming near MAF the past few runs so do not
anticipate much coverage in the Permian Basin this afternoon.
Should anything form, there will be enough potential instability
and shear that any storm could become marginally severe so will
have to keep an eye on this for the next few hours.
This week will be interesting with a quasi-stationary West Coast
trough keeping our area under southwesterly upper flow. This
pattern normally enhances precip chances though abundant moisture
is restricted to the eastern Permian Basin and so will be rain
chances this week. A cold front arrives Wednesday which could
expand rain chances farther west but otherwise the best rain
chances will be in the east. Temperatures will be above normal
until the frontal passage on Wednesday, with cooler temps lasting
into Thursday before conditions get warmer for the end of the
week.
Hennig
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 59 78 53 73 / 20 0 20 0
Carlsbad 52 78 47 66 / 10 10 0 0
Dryden 58 84 56 83 / 10 10 30 0
Fort Stockton 55 81 50 77 / 20 10 20 0
Guadalupe Pass 47 64 39 55 / 10 10 0 0
Hobbs 47 72 43 65 / 10 0 0 0
Marfa 43 72 37 68 / 10 10 10 0
Midland Intl Airport 55 79 51 72 / 20 0 20 0
Odessa 53 76 51 71 / 20 0 20 0
Wink 49 83 46 72 / 10 10 10 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...High Wind Warning from 2 AM to 8 PM MST Monday for Guadalupe
Mountains of Eddy County.
TX...High Wind Warning from 2 AM to 8 PM MST Monday for Guadalupe
Mountains.
&&
$$
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Monday)
Issued at 258 PM CST Sun Feb 18 2018
The strong southerly winds this afternoon will diminish slightly
after 00Z as the mixed boundary layer decouples slightly. The wind
advisory for the entire CWA will remain in effect through 6 PM.
An upper level trough across the northwestern US will dig south-
southeast into the southwest US. Strong southwesterly mid-level
flow across the central Rockies will cause a lee surface cyclone
to deepen across southeast CO. A strong southwesterly low-level
jet will advect deeper moisture northeast across the CWA. An EML
will overspread the CWA and there may be enough isentropic lift
for scattered showers and perhaps an elevated thunderstorms
developing. The RAP and ARW show the most MUCAPE across the CWA
with 400-800 J/KG while the NAM and GFS show only 100-300 J/KG.
Therefore, I cannot rule out an elevated thunderstorm after
midnight and through the morning hours of Monday. As the low-level
moisture increase through the night there could be some patchy
drizzle. However, we may be mixed deep enough with the stronger
low-level winds that drizzle may not develop.
Monday, Stronger CAA across the central plains will cause a surface
cold front to push southeast across the CWA through the day. The
front may move just southeast of the CWA before becoming stationary
across south central and southeast KS due to a deepening surface low
and surface pressure trough from southeast CO, east-southeast
across north central OK, then northeast across central MO.
Temperatures across north central KS will start out in the 40s and
lower 50s in the early morning hours but fall through the 30s
into the upper 20s by late Afternoon. As the H5 trough across
lifts northeast into the high plains, stronger isentropic lift
will develop north of the front where an area light rain will
develop. The rain across northeast and north central KS may change
over to light freezing rain through the afternoon hours. East
central KS will see highs in the lower to mid 60s during the mid
morning to early afternoon hours with temperatures falling into
the 40s through the late afternoon hours. Temperatures across east
central KS will remain warm enough for only rain through the
afternoon hours. There is still some question on how far southeast
the front will make it during the late afternoon hours. Most of
the shorter range models have the front pushing southeast of the
CWA and most forecast soundings only show only elevated CAPE above
the shallow colder airmass which will advect southeast behind the
front. At this time the surface based convection will occur south
and southeast of the CWA along the front, where there may be a
threat for gusty winds and perhaps large hail with any rotating
storms.
.LONG TERM...(Monday night through Sunday)
Issued at 258 PM CST Sun Feb 18 2018
Tonight and Tuesday, As the H5 trough across the southwestern US
lifts northeast into the central plains there will be stronger WAA
across eastern OK and southeast KS which will cause the front
across southeast KS to lift northwest into the southeast counties
of the CWA. The stronger CAA will remain across the western and
northern counties of the CWA. Periods of light freezing rain will
continue across northeast and most of the western and central
counties of the CWA. Temperatures will remain above freezing
across much of east central KS through the night. The greatest ice
accumulations will occur across the northeast and north central
counties, southwest into the central counties of the CWA where
0.1" to 0.2" of ice may accumulate through the overnight hours
into the morning hours of Tuesday. However, if the boundary pushes
even farther northwest then temperatures may warm closer to or
slightly above freezing and ice accumulation may be less than
forecasted. A winter weather advisory may be needed for areas
northwest of a Nortonville, to St. Marys to Council grove line
Monday night through the morning hours of Tuesday.
As the upper trough lifts out into the central plains the stronger
CAA will push the front and colder air southeast across east
central KS after 12Z. The area of rain across east central KS may
mix with or change over to freezing rain before ending early
Monday afternoon. The 00Z NAM model solution shows a stronger
push of colder air across east central KS during the morning
hours, which may cause a longer duration of freezing rain through
the late morning into the early afternoon hours of Tuesday across
east central KS. We`ll have to keep an eye on temperature trends
and when the steadier rain shifts southeast of the CWA. If the 00Z
NAM solution ends up being more accurate, then there could be up
to 0.1" of ice accumulations across east central KS from 15Z
through 20Z. However, the NAM QPF looks to be a bit too high
given that 850mb winds begin to veer as the H5 trough lifts out
into the central plains.
Highs on Tuesday will occur in the morning hours across east central
with temperatures in the mid 30s to 40s. Temperatures across east
central KS will fall through 30s into the upper 20s during the
late morning and early afternoon hours, as the surface front
pushes southeast across MO. Temperatures across north central and
northeast KS will remain steady in the upper 20s to lower 30s.
Tuesday night through Sunday, A longer wave length trough will
remain across the western US. A shorter-wave length trough will
lift northeast across the plains bringing a chance for light rain
Thursday afternoon which will chance over to snow or freezing
rain, depending on the thermal pattern aloft. A second upper
trough will lift out across the plains Friday into Saturday.
Temperatures will warm into the 40s and 50s, thus the precip will
fall as rain. Though coder air Friday night may change the precip
back over to light snow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 515 PM CST Sun Feb 18 2018
MVFR ceilings are approaching the taf sites currently and should
arrive in the next hour or two. Towards sunset there may enough
saturation and lift for drizzle as the winds gradually decrease
ahead of an approaching front. An isolated shower may develop near
TOP/FOE prior to the frontal passage. Some guidance is also
suggesting possibly enough instability for thunder showers along
the front at TOP/FOE in the late morning and early afternoon.
Winds shift to the north behind the front and will not be as
gusty. Ceilings will likely drop down to IFR prior to the front
then gradual improvement through the day tomorrow.
&&
.FIRE WEATHER...
Issued at 258 PM CST Sun Feb 18 2018
Strong southerly winds of 25 to 35 MPH with gusts of 35 to 45 MPH
will continue through the remainder of the afternoon hours, and will
only diminish slightly after 00Z. Even though RHs have steadily
risen above 40 percent through the afternoon hours, the
combination of dry fuels and strong southerly winds will cause a
very high fire danger the remainder of this afternoon and into the
evening hours. Any outdoor burning should be postponed.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 6 PM CST this evening for KSZ008>012-020>024-
026-034>040-054>056-058-059.
&&
$$
SHORT TERM...Gargan
LONG TERM...Gargan
AVIATION...Sanders
FIRE WEATHER...Gargan