Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/15/17
Area Forecast Discussion
National Weather Service Columbia SC
731 PM EDT Sun May 14 2017
.SYNOPSIS...
High pressure will hold dry weather and above normal
temperatures across the area through the work-week. The return
of a moist southerly flow will bring chances for diurnal
showers and thunderstorms next weekend.
&&
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
There is northwest flow aloft across the region with
strengthening low-level inversions as high pressure builds in
from the west. Tonight, mostly clear skies, light winds and a
dry airmass will allow for moderate to strong net radiational
cooling. Temperatures will cool down to the upper 50s to lower
60s. A dry airmass and weak mixing with a 15 kt LLJ will
preclude fog formation.
&&
.SHORT TERM /7 AM MONDAY MORNING THROUGH WEDNESDAY/...
An anomalously deep upper low will move northeast off the New
England coast. Continued northwest flow aloft for our area. A weak
short wave trough is forecast to move through the area during the
day Monday, but air mass appears dry and with weak instability.
There is a front to the north in North Carolina and the GFS is
hinting at some convection in the Carolina mountains and in south
central NC during the afternoon...possibly advecting into Pee Dee
during the evening. GFS ensemble pops quite low. Given downslope...
resulting limited moisture and high LFC/mid level cap will continue
dry forecast with warming trend.
The upper ridge over the central CONUS will gradually move east
across the region through Tuesday...with the ridge axis moving
off the coast on Wednesday. Surface high pressure over the area
will move off the coast Tuesday. Dry forecast with above normal
temperatures in store. Should see highs in the lower 90s with
lows in the low to mid 60s. Normal highs for this time of year
are in the lower 80s with normal lows in the mid 50s to lower
60s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Models indicate a mean upper ridge east of the Mississippi
River and a mean upper trough over the western states into next
weekend.
Surface high pressure over the western Atlantic extending into the
area will keep any surface fronts to our north and west through
Thursday. The ECMWF pushes a backdoor front into the area on Friday
as the upper ridge is suppressed southward. The GFS holds the front
north of the Midlands. Our forecast is more in line with the
GFS. We indicated low chance for diurnal convection over the
weekend given the return of a warm, southerly low level flow.
Temperatures through the long term will remain above normal.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Mainly VFR conditions expected to dominate the period...with
periods of mvfr/ifr fog possible at AGS late tonight.
With drier air over the region skies will be mostly clear
through the period with light and variable winds. Main concern
will be fog potential after 06z at AGS. Persistence forecast
overnight at AGS would include fog. Hrrr model does show very
shallow moisture layer near the river near AGS. Have included
mvfr visibilities for much of late tonight, with possible tempo
ifr conditions overnight. With drier air in place confidence in
development and coverage at any of the other taf sites is
currently too low to mention in TAFs.
EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected through Friday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Dodge City KS
904 PM CDT Sun May 14 2017
.UPDATE...
Issued at 904 PM CDT Sun May 14 2017
Thunderstorms have ended for this evening, with no further
development anticipated. Updated grids to remove all pops through
sunrise.
&&
.SHORT TERM...(This evening through Monday)
Issued at 330 PM CDT Sun May 14 2017
The mid-afternoon analysis confirmed large scale warming across the
Central Plains with many locations reaching mid to upper 80s. A very
weak front that pushed south across western Kansas earlier this
morning stalled out along a Hays to Garden City line with winds
light and variable along this corridor. Observations suggest a zone
of weak convergence along this front with 0-2.5km AGL lapse rates
reaching dry adiabatic from Elkhart to Guymon and points south and
west from there. At the nose of warm, deep boundary layer, some
incipient cumulus were developing in the central OK Panhandle.
Cumulus should continue to develop along the convergence axis with
the boundary starting to slowly lift back north through early
evening. HRRR and HRRRX indicate potential for isolated to widely
scattered convection just about anywhere along this convergence axis
across SW KS into the panhandles, worthy of some 20 POPs. Any
convection should be mainly diurnal, and thus expected to decay an
hour or two after sunset. The CAPE/Shear environment is only
marginally favorable for supercell structures, and even the 1500-
2000 J/kg CAPE will not likely be fully realized given the very weak
upper level forcing for ascent. Nevertheless, a wind gust to 60 mph
and hail up to half dollar size is possible from the strongest
isolated storm.
South winds will continue through the night as we remain in the
southwest flow pattern aloft. Winds in the 10 to 15 mph range
through the night should help keep temperatures fairly mild, with
lows in the lower to mid 60s just about everywhere.
As we head into Monday, the upper level ridge axis will continue to
move farther away from our region with stronger southwest flow in
the mid-upper troposphere. 500/250mb winds will become 40/50 knots
respectively vs. the 30/35 knots we are seeing this afternoon.
Improved moisture will also lead to higher SBCAPE by late afternoon
with surface dewpoints in the upper 50s to near 60 east of the
dryline. Speaking of the dryline itself, it should become a bit
better defined with stronger southwesterly momentum. The dryline is
expected to sharpen up along roughly a Guymon to Garden City to
Scott City line by late afternoon. Locations along the dryline that
see strongest convergence should see surface-based convective
initiation in the 21-23z time frame. The CAPE/Shear profile tomorrow
will be quite a bit improved with stronger flow at all levels of the
troposphere and SBCAPE reaching 2000-2500 J/kg all up and down the
dryline. Dryline convective mode would favor supercell storms, but
as mentioned earlier, it is difficult to determine right now where
along the dryline the supercells will develop and track. There may
be two or three spaced widely apart from west central KS into the
southern Texas Panhandle. Nevertheless, will be carrying some 30-40
POPs east of the dryline late tomorrow afternoon into the evening
hours. Remember, mature supercell storms can produce 2+ inch
diameter hail, 70+ mph winds, and even tornadoes -- although the
hail component would be the greatest concern as it appears now.
.LONG TERM...(Monday night through Sunday)
Issued at 330 PM CDT Sun May 14 2017
Tuesday will likely be an active severe weather day across much of
the southwestern KS through southwest Texas corridor. Global models
show a surface low deepening down to 990-992mb with enhanced
downslope momentum south of the low and along/west of the dryline.
The dryline by late afternoon should extend along a line from
roughly Hill City to Dodge City to Canadian, TX. Good convergence
along the dryline should support aggressive surface based
convection. 500/250mb flow will increase even more to the tune of
50/75 knots, respectively. The shear profile puts convective mode
well into supercell category and when you add in the low level
moisture factor, the CAPE/Shear combination would support longer
lived supercell storms, potentially capable of high end severe
weather, including tornadoes, from west central KS and points south.
As we head deeper into the work week, the forecast becomes more
difficult regarding severe weather risk. The initial storm system
Tuesday is stronger and farther south than previously expected, and
this will play into the forecast Wednesday-Thursday. On Wednesday,
The Pacific Cold front (acting dryline) will push way east into far
eastern KS/OK as west winds surge dry air into our region. Drier air
will preclude thunderstorm activity Wednesday as west winds prevail.
That said, as the first low lifts out, some wrap-around moisture may
clip the Hays area through the afternoon hours, although this should
be more showery in nature vs. thunderstorms.
Right on the heels of this first storm is a much larger system,
allowing for aggressive cyclogenesis again on the High Plains by
Thursday. This storm, however will be working with dry air across
southwest KS all day Thursday. It will take significant cyclogenesis
and backing of low level winds to bring the moisture back northwest
into southwest KS. For this reason, there is a bit lower confidence
this forecast cycle, as far as how far northwest significant severe
weather will reach into the southwest KS region. The evening hours
Thursday will be very critical, because this is the time frame when
low level moisture can come roaring back northwest as winds back
around to the southeast. The GFS and ECMWF both show lower 60s
dewpoints pulling back as far west as a U283 corridor during the
early evening hours. The cyclogenetic environment with significant
low level wind shear would support tornadic supercell storms
Thursday evening, particularly south of the Arkansas River and east
of U283.
Global models are now showing the large upper low will remain quasi-
stationary through Friday, so that another round of severe weather
could impact western Kansas Friday. These solutions are slower and
farther west than before, putting more of western Kansas in a threat
for severe weather. This entire trough will not push east of
southwest Kansas until sometime late Saturday, now, per the ECMWF.
If this is the case, then even an early afternoon strong/severe
weather threat cannot be ruled out. Also, if the ECMWF is any decent
guidance at all, much of southern and western Kansas should see
quite a bit more rain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 600 PM CDT Sun May 14 2017
VFR expected to prevail at all airports through Monday. Convection
currently SW of GCK and west of LBL is expected to weaken this
evening with little impact on aviation. Widespread low level wind
shear is expected after 03z as low level jet once again increases
850 mb winds to near 50 kts. After 15z Mon, strong south winds
will impact aviation at all airports, averaging 25-35 kts. Expect
convection to redevelop along the dryline around 00z Tue, along a
GCK-LBL line. Mentioned CB/VCTS for these TAFs at the end of the
TAF period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 65 90 63 84 / 10 20 40 40
GCK 62 91 61 85 / 20 30 30 20
EHA 60 88 57 84 / 10 20 10 10
LBL 64 89 61 86 / 20 30 30 30
HYS 64 91 65 86 / 10 10 30 30
P28 64 90 65 83 / 0 10 10 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Turner
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Turner
Area Forecast Discussion
National Weather Service North Platte NE
622 PM CDT Sun May 14 2017
.SHORT TERM...(This evening through Monday)
Issued at 325 PM CDT Sun May 14 2017
The consensus in the HRRR and RAP models is for an isolated
thunderstorm chance tonight. This is unusual...especially the HRRR
which is normally very aggressive. These models appear to be drawing
sufficient dry air south ahead of the disturbance to keep rain
chances very low.
The NAM is the most bullish and suggests scattered coverage. Clearly
the model suggests a compact MCS structure moving east across the
Sandhills late tonight. The GFS appears to be in between but is
placing the rainfall farther south...closer to the 850mb front
across Srn Neb. This is because it too is drawing dry air into Ncntl
Neb.
The forecast uses a blend of all of these models for a 30 percent
chance of showers and thunderstorms tonight. Forecast confidence
is low given the wide spread and uncertainty in the model data.
SPC suggested a marginal risk for severe thunderstorms across Wrn
Neb this evening. Confidence in this is also low except for Swrn Neb
where the h850mb front will be. Otherwise, the thunderstorms...if
they develop...will move east this evening and become increasingly
elevated.
Presumably...the 850mb front will lift north Monday and be the focus
for isolated to scattered showers and thunderstorms across either
Ncntl Neb as indicated by the slower GFS model or South Dakota as
indicated in the faster NAM solution. Scattered thunderstorms are in
place during the morning with isolated coverage for the afternoon.
The GFS and NAM indicate 2500-3500 J/KG of CAPE and bulk shear
around 40kt during the afternoon. This is a favorable balance for
supercell development. Any storms which develop could be strong or
severe and SPC suggested a marginal, 5% risk area for severe storms
covering all of western and north central Nebraska. The low risk
across is western and north central Nebraska based on isolated storm
coverage.
.LONG TERM...(Monday night through Sunday)
Issued at 325 PM CDT Sun May 14 2017
The LLJ increases Monday evening and could be sufficient forcing for
isolated showers or thunderstorms...mainly east of highway 83 in the
deeper moisture. The better focus appears to be across the Dakotas
closer to the nose of the warm air advection aloft. The threat of
isolated strong or severe storms should continue overnight.
Another cold front will drop into or through the area Tuesday. This
will be an excellent focus for storm development Tuesday night as a
strong disturbance moves across the Cntl Rockies and lifts through
Wrn/Ncntl Neb. The NAM maintains good instability west into Ncntl
Nebraska while the GFS is farther east across ern Neb. Using the
NAM, severe storm development is possible anywhere east of highway
83 and this is close to the SPC day outlook appears to be a
compromise between the two models. The WPC day 3 qpf would appear to
be along and east of highway 83 for storm development.
The disturbance Tuesday will be strong enough to drop a substantial
cold front through Wrn/Ncntl Neb and cool temperatures into the 60s
and 70s Wednesday. Post frontal cold air advection continues
Thursday through Saturday with highs just in the 50s and 60s. The
model consensus indicates cool air still in place next Sunday with
highs in the 60s.
Chance to likely POPs are in place Wednesday through Friday with a
cold dome providing the basis for isentropic lift. A large upper low
across the Cntl Rockies will move very slowly east. Next weekend
appears to be cool and dry.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 621 PM CDT Sun May 14 2017
Main forecast challenge for tonight involves chances for TSRA
development across the west initially, then moving east through
the night.
Short range convective allowing models have varied in their
solutions, with the operational HRRR dropping the development of
TSRA in southwest NE with its latest run which is a drastic change
from previous runs. However TSRA across NC NE remains. Exper HRRR
still suggesting potential for TSRA later tonight for the KLBF
TAF. So confidence is higher in TSRA development across nc NE
which would impact KVTN, but a bit lower for TSRA development in
the southwest. That said, with good LLJ developing tonight and
mesoanalysis indicating mid level instability and mid level
forcing increasing tonight, do believe TSRA development is
possible, though have not included in KLBF TAF at this point due
to uncertainty in coverage should storms develop.
After the passage of storms overnight will see VFR conditions for
Monday with more storm development possible after this period.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Stoppkotte
Area Forecast Discussion
National Weather Service Marquette MI
749 PM EDT Sun May 14 2017
.SHORT TERM...(This evening through Monday)
Issued at 443 PM EDT SUN MAY 14 2017
Water vapor imagery and RAP analysis show mid/upper ridge over the
central CONUS with axis just w of the Mississippi River. On either
side of the ridge, fairly deep trofs are located over the western
CONUS and over the Lower Great Lakes/New England. Vigorous shortwave
lifting into southern Saskatchewan aided shra/tsra across the
Dakotas earlier today. That pcpn has almost completely dissipated
with just a few isold -shra remaining in northern MN where stronger
850mb theta-e advection is occurring. Closer to home, during the
morning, a band of mid clouds extended from ne OH across central
Upper MI to nw of Lake Superior within a band of mid-level fgen well
to the ne of a sfc stationary front across central MN to northern
IN. Those clouds have dissipated in the last few hrs, leaving behind
a mostly sunny day across the fcst area.
Tonight, sfc high pres ridge extending s into Upper MI will shift e
in response to eastward movement of the mid/upper ridge. Meanwhile,
vigorous shortwave now over southern Saskatchewan will move out
across central Manitoba. Weakening low-level trof associated with
this wave, currently over the far eastern Dakotas will reach western
Lake Superior/nw WI by 12z Mon. Modest increase in 850mb winds to
20kt or so ahead of the trof will transport upstream theta-e ridge
toward Upper MI with rather sharp gradient noted. Seems quite
reasonable that some elevated shra will develop along the theta-e
gradient as noted by all model guidance, probably affecting portions
western Upper MI late tonight. Since mucape is fcst as high as about
500 j/kg, some thunder is certainly possible. There is uncertainty
about location of pcpn development. Roughly half of the 12z guidance
and most of the hourly RAP/HRRR runs today are pointing toward a
southward shift from previous guidance for where shra might develop.
Instead of MN arrowhead, focus may now be down toward far nw
WI/Appostle Islands into far western Upper MI. Fcst will lean toward
this trend. Increasing clouds and light southerly winds will hold up
min temps over the w. Expect the lowest readings over the e, closer
to the retreating sfc high pres ridge. Some of the traditional cold
spots over the interior e could see temps down to 32F.
On Mon, low-level trof is fcst to weaken as it continues eastward
while near sfc trajectories maintain drier air into the eastern fcst
area. This should result in any shra/tsra over western Upper MI in
the morning dissipating as they track eastward into central upper
MI. While fcst will reflect this drying idea, have some concern that
the progression of the sharp theta-e gradient eastward may continue
to maintain some -shra into the eastern fcst area. After the -shra
dissipate, don`t see a whole lot to generate additional shra during
the aftn. Temps away from lake moderation, Keweenaw and near Lake
Michigan, will rise into the 60s with some lower 70s west.
.LONG TERM...(Monday night through Sunday)
Issued at 413 PM EDT SUN MAY 14 2017
After a fairly quiet first half of May, the weather pattern becomes
quite active across the western Great Lakes this week. Multiple
disturbances ejecting ahead of broad troughing across the western
CONUS will bring multiple rounds of rain and thunderstorms, with
severe storms possible Tuesday and possibly Wednesday.
Monday night through Tuesday night: A warm front associated with low
pressure over the central Plains will lift northward across the CWA
late Monday night into Tuesday afternoon. Moisture transport and
isentropic lift on the warm front will bring a chance of rain late
Monday night into Tuesday afternoon. However, guidance disagrees on
how quick this front will lift northward and how high precip
coverage will be, mainly owing to the handling of growing convection
across southern MN and WI Monday Night. HiRes guidance is indicating
that this convection will limit the northward extent of moisture and
instability Monday night, thereby limiting precip coverage across
the CWA well into Tuesday. However, if this MCS does not form as
suggested by LowRes guidance, a shield of rain will expand northward
across the area during the night. MuCape is fairly meager with this
precip, so only some embedded thunder is expected with any precip
through Tuesday morning.
Confidence in convective evolution beyond Tuesday morning is low
given the dependence on how early morning convection unfolds (or
doesn`t unfold). Indications are that the warm front will clear all
but the far northern and eastern CWA by mid afternoon. Some clearing
will be possible across the interior west and central during the
afternoon if debris clouds from early morning convection thin out.
If enough clearing occurs, convective indices will support organized
discrete severe convection from northern WI into the western CWA
closer to the surface low over the Upper MS Valley. Definitely a lot
of uncertainty with this scenario, especially if thick clouds linger
through the afternoon. Either way, any convection on Tuesday into
Tuesday night will produce gusty winds via momentum transport from a
50kt wind max between 850 and 750 hPa.
As an added note, the 12Z NAM is the most aggressive solution with
pushing the warm front across the CWA and developing severe
convection Tuesday. With this scenario, gusty southerly winds
combined with RH values in the 50s may pose some wildfire concerns
during the afternoon if any early morning lightning initiates fires
where fire fuels are susceptible to burning.
Wednesday and Wednesday night: A compact mid-level low ejecting from
the southern Plains early in the morning will interact with a
relatively moist airmass and the trough lingering over the Upper MS
Valley. Conditions look favorable for a narrow band of heavy rain
somewhere from NW WI to the western CWA, with 2-3" of rain over a 12
hour period late Wednesday afternoon through Wednesday night.
Thursday through Sunday: Troughing will clear the area Thursday
afternoon ahead of upper ridging and cooler weather shifting across
the area on Friday. A cooler pattern with wetter conditions will
then prevail for the weekend as a couple waves embedded in deep
troughing over the northern and central Plains cross the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 748 PM EDT SUN MAY 14 2017
A relatively dry low-level air mass should allow VFR conditions to
prevail at KIWD/KCMX/KSAW thru this fcst period. While there could
be a -shra and perhaps even a rumble of thunder at KIWD late
tonight/Mon morning and also at KCMX Mon morning, potential is low
enough to maintain VFR conditions. However, if shra do occur at
KCMX, upslope flow and low-level moistening from the rainfall could
result in MVFR cigs developing later Mon morning.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 413 PM EDT SUN MAY 14 2017
Winds through much of the upcoming week will remain at 25 knots or
less. The one exception will be north winds to 30 knots behind a
departing low pressure system Wednesday night into Thursday. As more
humid air arrives over the relatively cold lake waters, fog will
develop Tuesday night then linger through Wednesday. This fog may be
dense across eastern Lake Superior late Tuesday night into
Wednesday. The fog will dissipate with the arrival of drier air on
northerly winds Wednesday night.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Kluber
AVIATION...Voss
MARINE...Kluber
Area Forecast Discussion
National Weather Service Pueblo CO
306 PM MDT Sun May 14 2017
.SHORT TERM...(This evening through Monday)
Issued at 306 PM MDT Sun May 14 2017
The front that slipped into eastern CO has held firm across
southeast CO which has netted more of a southeast to east wind
across the plains through the afternoon. Mixing has still been
sufficient behind the front to knock down dew points into the upper
30s and lower 40s this afternoon resulting in CAPE values under 1000
j/kg. Meanwhile...southwest flow aloft has brought breezy winds and
another drop in dew points across the mountain area with readings in
the teens.
Next embedded shortwave has spread some mid/high level moisture into
CO and CU field in satellite imagery is looking agitated along the
southern Sangres ahead of this feature. As it advances into
southern CO this evening...various high res models trigger isolated
thunderstorms across the far southeast plains along the old frontal
boundary which slowly lifts northeastward during the evening.
Suspect CAPE will be too limited for much of a hail threat...and
latest hrrr run seem to be backing off on storm strength out that
way. However with inverted V soundings...certainly a high wind
downburst threat still looks possible. Best chance will be before
03z. Otherwise should see a persistent cirrus deck which slowly
breaks towards morning. Lee trof should keep westerly drainage
winds across the area resulting in a warmer night than last night
along the east slopes and plains. Mountain areas will see min temps
similar to slightly warmer than last night as well.
Warmer temperatures can be expected for Monday as southwest flow
aloft mixes down in the afternoon ahead of the closed low taking
shape across the desert southwest. Dry line will sharpen up along
the CO/KS border in the afternoon bringing another threat for
thunderstorms across the far eastern counties during the afternoon
and evening. Still looks like best severe parameters will be along
or just east of the border. -KT
.LONG TERM...(Monday night through Sunday)
Issued at 306 PM MDT Sun May 14 2017
Two weather systems to dominate the extended forecast.
Monday night through Wednesday...Models are in fairly close
agreement through midweek. An upper low over the desert southwest
will produce strong south-southwest flow across the Four Corners and
the CWA Mon night and Tue, before opening up and ejecting across the
state Tue night. This system then strengthens again as it passes to
the east of the state Wed morning, then the next low pressure system
approaches the region from the northwest Wed aftn and eve. This
solution is about 12 hrs slower than previous thinking the past few
days, and indicates a shorter break between the two weather
features. Expect scattered pcpn chances for the higher terrain and
isolated activity for the plains on Tue as the system passes
overhead. Cloud cover and pcpn chances will then increase
significantly on Wed ahead of the next system. Wed is forecast to be
about 5 degrees cooler as compared to Tue for all areas, but in
general expect highs in the 50s and 60s for the high valleys, and
upper 60s to lower 80s for the plains both days. Overnight min temps
are expected to be rather mild as well due to brisk winds Tue and
extensive cloud cover Wed.
Thursday through Sunday...A strong upper low pressure system drops
to the southeast and parks over UT and CO for Thu and Fri, then
slowly ejects to the north across the Northern Rockies on Sat. The
system slowly edges to the east on Sun, with northwest flow aloft
settling in over Colorado. There are some discrepancies between
extended models, with the GFS indicating a slightly faster movement
as well as a more northern placement. The differences in timing and
location make it very difficult to pinpoint what will happen with
respect to pcpn timing and amounts as the region heads into the next
weekend. Therefore, relied on the extended procedure heavily which
painted scattered to likely pops for most areas Thu and Fri,
tapering off to isolated pcpn chances for Sat and Sun. As for temps,
look for 50s for the high valleys and 60s to lower 70s for the
plains on Thu. For Fri and Sat, max temps in the 50s and 60s are
forecast for all areas. Temps will then climb back into the 60s and
70s for most areas on Sun as the system pulls away. Moore
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 306 PM MDT Sun May 14 2017
VFR conditions expected at the TAF sites through the afternoon with
breezy southeast winds at KCOS and KPUB decoupling around 02-03Z.
KALS will see breezy southwest winds which should also decrease
around the same time. Gusts to around 20 to 25 kts will be possible
at all three terminals during the late afternoon through the
evening. Otherwise winds overnight will be light. Winds pick up
again from the south to southwest at all three terminals in the
afternoon with gusts to 25 kts possible around or a little after
18z. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MOORE
AVIATION...KT
Area Forecast Discussion
National Weather Service Blacksburg VA
647 PM EDT Sun May 14 2017
.SYNOPSIS...
Low pressure will continue to wobble off the New England coast
through Monday. A weak front will move southeast crossing the area
tonight into Monday. High pressure will build across the area with
the weather pattern becoming more summer-like heading into midweek.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 647 PM EDT Sunday...Regional radar mosaic depicts spotty,
isolated to widely scattered showers developing across the
mountains of central and eastern WV. Activity being aided by
weak diurnal instability and on the warm side of a backdoor
frontal zone to our north across northern Virginia, West
Virginia and eastern Ohio. While these showers should continue
at an isolated to widely scattered coverage through sunset, it
is something of a question mark when these stop. Recent HRRR
cycles and the 18z run of the 3-km NAM actually continue the
showers even well after dark, perhaps aided by a weak mid- level
vort max over south- central Ohio per RAP analysis. Kept the
idea of isolated showers through 04z, but am hesitant to extend
the showers into the overnight given the diurnally unfavorable
time of day. Only few locations in Greenbrier, Bath and
Alleghany Counties in VA stand the best shot at seeing a light
shower and it`s not something that plans should be stopped for.
Front still appears to progress southward across the central
part of the forecast area after midnight, with a slight veer to
the winds toward a northwest direction along with drying
dewpoints.
Previous near-term discussion issued at 345 PM follows...
Broken clouds and maybe a sprinkle will accompany a weak front
coming across the mountains tonight. This front will stall along the
Blue Ridge by dawn tomorrow. Models are hinting at a surface
reflection developing along the front and over the southwestern
Virginia foothills by the afternoon. This reflection and possibly a
shower will help push the weak front south into North Carolina by
Monday evening.
Mild temperatures expected tonight with readings in the 50s.
Despite the passing of a front, temperatures will once again warm
above normal with low to mid 70s across the mountains and low 80s
east of the Blue Ridge.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 345 PM EDT Sunday...
Large ridge of High Pressure will build over the southeastern
United States by mid week. This will result in moderating
temperatures and increasing dewpoints with summerlike pattern
developing regionwide. Aside for some diurnal cumulus, skies
will be mostly clear. Any shower threat looks minimal per
capping inversion developing aloft. At most an isolated
shower/thundershower in the mountains, but coverage not enough
to warrant placing in the forecast attm.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 345 PM EDT Sunday...
The mean pattern for the end of the week will feature a high
amplitude ridge of high pressure east of the MS River, and an
anomalous long wave upper trough over the intermountain West.
The trough will transition into the central part of the country
by the weekend, the upper ridge flattening across the eastern
CONUS. This pattern will set up an active period of weather for
the central part of the country some of which could reach the
Mid-Atlantic for the weekend as the upper ridge breaks down.
Temperatures will remain warm headed into the weekend with
increasing dewpoints preventing temperatures from falling below
60. Daytime highs in the 80s will be common, and 90 is not out
of the question for areas east of the Blue Ridge.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
As of 647 PM EDT Sunday...
VFR conditions anticipated through the TAF period. Initially
breezy northwesterly wind conditions will abate with nightfall.
A backdoor front will make its way southward across the central
part of the forecast area after 06z. I can`t entirely rule out a
light shower at LWB and perhaps BCB and ROA through the evening,
but it would likely be isolated at cigs/visbys being
unrestricted. Should see west to west- northwest winds become
briefly light and variable in the surface frontal trough before
becoming northwest again towards morning.
Continued VFR into Monday as well with northwest winds 7-10 kts.
Note: The ASOS equipment at Lynchburg (LYH) has suffered a power
hit. While observations are currently being augmented, it`s
expected that wind, visibility and present weather elements will
be lost tonight until power can be restored. In keeping with
the total observation concept, scheduled amendments to the LYH
TAF will be suspended until that time, with AMD NOT SKED
appended to the 00z TAF issuance.
Extended Aviation Discussion...
Dry and becoming summerlike this week. VFR conditions are
anticipated for most of the time, outside any valley fog.
Some isolated MVFR convection may develop Wednesday and Thursday
mainly across the high terrain.
&&
.EQUIPMENT...
As of 632 PM EDT Sunday...
Electronics technicians have informed that the ASOS equipment at
Lynchburg (LYH) has suffered a power hit. Repairs at the site
cannot be performed until Monday morning. While observations are
being augmented on-site, it`s expected that several weather
elements will no longer transmit by this evening until power can
be restored.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...RCS
NEAR TERM...AL/RCS
SHORT TERM...PM
LONG TERM...PM
AVIATION...AL/RCS
EQUIPMENT...AL
Area Forecast Discussion
National Weather Service San Angelo TX
656 PM CDT Sun May 14 2017
.AVIATION...
/00Z TAFS/
MVFR stratus will move into southern terminals early morning,
scattering out mid to late morning. Stratus may reach as far north
as San Angelo, but confidence is not as high, so will leave as a
scattered layer. Lee trough will continue to bring gusty south
winds over 20 KTS at times mid morning Monday through the
afternoon.
&&
.PREV DISCUSSION... /issued 332 PM CDT Sun May 14 2017/
SHORT TERM...
(Tonight and Monday)
A little bit of high-based cu developing well west across the
Permain Basin and South Plains this afternoon. The TTU WRF and the
HRRR show a few showers and storms developing early this evening and
getting close to the western border of the area around sunset,
mainly west of a Sweetwater to Sterling City line. Thus, have added
small PoPs out along the western portions of the Concho Valley and
Big Country for a few hours this evening. Much the same set-up for
Monday afternoon, with convection starting to develop across the
Permian Basin and South Plains but not approaching West Central
Texas until the evening hours.
As for temperatures, low level moisture will increase and provide
for slightly warmer overnight temperatures. Models suggest some low
cloudiness possible by sunrise Monday morning, but models also tend
to over estimate the extent of the low clouds the first night of
better return flow. Highs on Monday about where they are today,
reaching the low to mid 90s.
LONG TERM...
(Monday night through Sunday)
An upper level trough will be located across the Great Basin region
Monday night, putting West Central Texas in southwest flow aloft.
Isolated to scattered showers and thunderstorms are forecast to
develop along a dryline over West Texas during the late afternoon
hours. A few of these storms may move into our far western counties
during the early evening hours, before dissipating by mid to late
evening. Slight chance PoPs were continued for the western portions
of the forecast area.
On Tuesday, the aforementioned upper level trough will move toward
the Great Plains, with better large scale lift overspreading the
area by late in the day. Showers and thunderstorms are forecast to
develop by late afternoon along a dryline which will be just west of
our area. This convection will likely become more widespread during
the evening hours and move east across the forecast area.
An unstable atmosphere along with high 0-6 KM bulk shear values are
forecast across the region, which may lead lead to a few strong to
severe thunderstorms. Highs on Tuesday will be in the upper 80s to
lower 90s. Quieter conditiions are forecast on Wednesday, with highs
mainly in the upper 80s to lower 90s.
On Thursday, the next upper level trough/low will dig south across
the southern Rockies, once again putting West Central Texas in
southwest flow aloft. Models are indicating a disturbance moving
across the region, sometime late Thursday into Friday, which will
result in another increased chance of showers and thunderstorms. A
few strong to severe thunderstorms will once again be possible
across much of the region. Highs on both Thursday and Friday will be
slightly cooler, mainly in the mid to upper 80s.
Both the GFS and ECMWF show the previously mentioned upper level
trough remaining to our west for the first part of the weekend, then
slowly moving east toward the Plains on Sunday. At the same time, a
slow moving cold front is forecast to move through the area,
sometime Saturday into early Sunday. This may be the focus for
additional shower and thunderstorm development next weekend. Locally
heavy rainfall will also be possible as precipitable water values
increase to near 1.5 inches.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 65 91 68 86 / 5 5 10 20
San Angelo 65 93 69 89 / 10 5 10 20
Junction 63 90 68 85 / 0 0 10 20
Brownwood 63 90 66 83 / 0 0 10 20
Sweetwater 66 91 68 89 / 20 10 20 20
Ozona 65 88 69 87 / 10 5 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
99/99/04