Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/19/17
Area Forecast Discussion
National Weather Service Amarillo TX
636 PM CDT Mon Sep 18 2017
.AVIATION...
For the 00Z TAFs:
VFR conditions will prevail throughout the valid TAF period.
There are signs in the model output for low level wind sheer
around 1000 feet sometime around 06Z and 12Z between the three
terminals as a jet around 45 knots looks possible. I may add this
with an amendment after some newer model data comes in, but I
wanted to make note of that now for planning purposes. Its mainly
speeds shear as not much turning is evident from the surface
to the low level jet. Otherwise, it will be breezy tomorrow
afternoon into early evening.
Guerrero
&&
.PREV DISCUSSION... /Issued 231 PM CDT Mon Sep 18 2017/
DISCUSSION...
The cloudy start to the day has slowed our warming potential. Most
of the area has struggles to reach the 80 degree mark. This will
also hurt our storm chances given that we will struggle to break
the cap. The HRRR is still holding onto an isolated storm across
the eastern zones this evening. Have gone with a 10 POP to cover
this isolated chance but confidence is pretty low.
On Tuesday, we will see the typical Panhandle winds return to the
area. Southwestern winds will quickly be on the rise through the
morning hours as a lee side low moves across eastern Colorado.
Winds will top our in the 15 to 25 mph range with briefly higher
gusts. Given that our high temperatures are expected to be in the
90s could result in fire weather concerns (see Fire Weather
section below). Late Tuesday night into Wednesday morning, a cold
front is expected to drop into the Panhandles. Northerly winds and
a cooler airmass over the area will help to keep out high
temperatures near normal across the northern zones.
Thursday will see the upper flow become southwesterly as a low
moves southward from the Pacific Northwest. This pattern is
expected to persist through the weekend. This pattern will also
result in multiple chance for precipitation as embedded shortwaves
within the upper flow moves over the area. There will be enough
shear to draw the eye on the potential for organized convection.
Will continue to monitor as we move closer to the weekend.
FIRE WEATHER...
Thanks to slightly cooler high temperatures today our relative
humidities are not expected to drop below 20 percent today. On
Tuesday, we will see much warmer temperatures (daily highs
will run roughly 10 to 20 degrees above normal). These much warmer
temperatures will combine with dew points dropping into the 30s
and 40s to push our minimum relative humidities into the 12 to 20
percent range for the better portion of the Panhandles. Our winds
speeds will also be on the rise throughout the day on Tuesday as a
lee side low moves across eastern Colorado. The tightening
surface pressure gradient will result in 20 ft winds in the 20 to
25 mph sustained. These conditions will result in meteorological
critical fire weather conditions from the far western Oklahoma
Panhandle and the northwestern Texas Panhandle as well as elevated
fire weather conditions for all but the southeastern Texas
Panhandle. With that being said, much of this same area saw
wetting rains last night and early this morning. Wet fuels will
help to mitigate our fire weather expectations. A Fire Danger
Statement may be warranted for the far northwestern part of the
area for initial attack activity given how much drying will occur
tomorrow.
Cooler temperatures and lower wind speeds will prohibit elevated
fire weather conditions on Wednesday.
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
$$
99/99
Area Forecast Discussion
National Weather Service Burlington VT
723 PM EDT Mon Sep 18 2017
.SYNOPSIS...
High pressure will dominate our weather for the week. The high
pressure will also keep Jose well south of New England, so all
that we will see is an increase in clouds and chances for
showers across central and southern Vermont late Tuesday and
Wednesday. The rest of the region will remain dry this week. The
high pressure will also keep temperatures above normal.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 505 PM EDT Monday...Modest update for late
afternoon/early evening to increase pops across the southern
Champlain Valley and the western Adirondacks per greater
coverage of shower activity than prior indications. Could be a
stray rumble of thunder, but lapse rates aloft aren`t all that
impressive - limiting overall updraft strength. A few of the
showers could put down brief heavier downpours through sunset as
evidenced by prior MRMS estimates of between 0.50 and 1.50
inches in southwestern Rutland County in the Lake St.
Catherine/Wells/Poultney areas. The rest of the forecast remains
on track as of 500 pm so no other adjustments needed at this
point. Enjoy your evening!
Prior discussion...
Forecast in decent shape for the afternoon. Did make some minor
adjustments based on latest radar trends for placement of the
initial small showers that have bubbled up over the higher
terrain. HRRR still seems the best of the convective models, so
followed it`s lead. Given the moisture depth is not all that
much and the amount of mid level dry air in place, the isolated
showers we get will remain across the higher terrain and will
not last long nor bring any significant precipitation. And 0%
chance of thunder. Temperatures across the region are at or
above previously forecast highs, so did adjust upward a couple
of degrees. It appears the smoke layer aloft is just a bit
thinner than it was yesterday, so we are getting just a little
bit more insolation to warm things up. Well, at least that is my
theory. Winds remain light, though there is a tendancy for them
to turn southeast across Vermont in response to Jose well to
the south.
Overnight: expecting another quiet night, with areas of fog once
again developing, especially in the more normal fog areas. Lows
again well above normal, with 50s to lower 60s.
Tuesday: Watching for low level moisture from the Atlantic
being advected westward into portions of eastern Vermont. More
guidance is picking up on this, and given the flow around Jose,
it does make sense. Thus expecting it to end up being a "murky"
looking day for southeast Vermont with low stratus hanging
tough, even after the morning fog lifts. The clouds will also
have an impact on temperatures, and continued with the idea of
only in the lower 70s down around Springfield, while near
80F/low 80s in the Champlain Valley and points westward. Looks
like that Atlantic moisture gets deep enough for some light rain
showers by afternoon. Liked how the NAM and NAM3km are handling
it, so used a model blend to drive the hourly PoP/weather
evoluton.
Tuesday night: 12z guidance didn`t suggest anything much
different than what we previously had. Looking at 35-50% chance
of light rain for roughly a St J to Rutland line and points
south. That should be the farthest northwest any rain shield
from Jose should make it. Even then, the rain won`t be heavy.
Maybe upwards of 1/4" of rain. Otherwise we are too far away to
see any strong winds. Once again, overnight lows will be above
normal with 50s to lower 60s.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 330 PM EDT Monday...Models continue to show the ridge
building over the region Wednesday-Wednesday night as Jose
begins a more easterly motion. This will keep most of the BTV
forecast area rain free. The exception may be far southern
Vermont where scattered rain showers related to Jose may
persist. Will hold on to a 30 pop to cover the low chance. Temps
should be closer but still slightly above normal in the lower
to mid 70s.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 330 PM EDT Monday...Forecast looks pretty quiet across
the region in the long term, with the ridge holding strong. Have
kept the forecast dry throughout the time period. The warm
temperatures will also continue with the area seeing a slow
warming trend.
&&
.AVIATION /00Z MONDAY THROUGH SATURDAY/...
Through 00Z Tuesday...VFR through most of the period with a few
exceptions. 1) Brief MVFR conds possible in lingering shower
activity across the Adirondacks through 02Z. 2) Patchy br/fg and
IFR/LIFR likely at KMPV/KSLK after 05Z, possible at KPBG/KMSS
though confidence lower at these latter terminals. 3) BKN/OVC
MVFR marine stratus may encroach northward into eastern/southern
VT after 06Z. Confidence low/moderate on how far north and west
this progresses overnight, but models do show a pronounced
southeasterly surge of 15-20 kts above 800ft tonight so time
will tell. If this surge is more pronounced than currently
forecast, then br/fg/ifr threat at KMPV would be lower later
tonight. After 12Z Tuesday...mainly VFR under light/modest
east/southeasterly flow from 5-10 kts, though again, if marine
stratus advances further northwest than currently forecast,
lower MVFR cigs could linger at southern/eastern terminals such
as KMPV/KVSF etc.
Outlook...
Tuesday Night: VFR. Slight Chance SHRA.
Wednesday: VFR. Slight Chance SHRA.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Nash
NEAR TERM...JMG/Nash
SHORT TERM...NRR
LONG TERM...NRR
AVIATION...JMG
Area Forecast Discussion
National Weather Service Hastings NE
655 PM CDT Mon Sep 18 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 255 PM CDT Mon Sep 18 2017
Stratus/low clouds have been slow to exit today, holding
temperatures down with most readings in the 70s across south
central Nebraska, with a few 80s in north central Kansas.
The pattern aloft depicted subtle southwest flow ahead of an upper
trough moving into British Columbia, while at the surface, a low
pressure trough was deepening along the front range of the
Rockies into the high plains region.
As we head into the evening, lingering low clouds will lift out
with steady southerly low level flow forecast through the
overnight hours. Models indicate the potential for isolated
convection overnight on the nose of the lowlevel jet which will be
oriented to our southeast, so have kept the dry forecast going
for our area with the better chances for this remaining to our
east/south. Have some concern for the development of fog given the
wet ground and high dewpoints, and light southeast wind
component. SREF probs and NAM visibilities both suggest the
northern half of our cwa may be more susceptible for fog and have
included patchy fog in the forecast.
Tuesday will be warm and windy in a tight pressure gradient/deep
mixing. The upper low in the Pacific Northwest translates into
Alberta with the upper trough digging into the northern and central
Rockies. The associated surface trough pushes east of the high
plains into western Nebraska and Kansas in the afternoon. Dewpoints
mix out, along and west of the boundary to the 30s/40s, with low
relative humidity values forecast below 20 percent for Furnas,
Phillips and Rooks Counties. The combination of low relative
humidity values, south wind gusts over 30 mph and favorable fuel
status across north central Kansas and southwest portions of south
central Nebraska have prompted a Fire Weather Watch for Tuesday
afternoon. Outside the Fire Weather Watch area, near critical fire
weather conditions are expected for locations west of a line from
Lexington, Nebraska to Smith Center, Kansas. Temperatures will be
noticeably warmer, reaching the upper 80s to mid 90s for highs.
.LONG TERM...(Tuesday night through Monday)
Issued at 255 PM CDT Mon Sep 18 2017
After a brief cooling behind a cold front Wednesday, warm weather
will settle in for the remainder of the workweek, followed by a cool
and wet weekend.
A cold front pushes southeast Tuesday night as the lead upper low
tracks across Canada and this boundary looks to move through dry.
High pressure builds south behind the front Wednesday and
temperatures will drop back to near 80F for highs in the slightly
cooler air. The surface ridge axis departs to the east Wednesday
night with return flow of southerly winds and warmer air returning
to the plains, ahead of an upper trough digging along the west
coast. The pattern will become highly amplified by the end of the
workweek with the plains in southerly flow aloft in between the
intermountain/western trough and an upper ridge from the gulf to
the Ohio Valley/Great lakes region. Thursday and Friday are
looking warm and windy with highs well above normal in the upper
80s/low 90s (normal highs average in the upper 70s this time of
year), with winds steady/gusty from the south.
Chances for rain ramp up over the weekend as the upper trough axis
edges farther east into the Rockies with the associated frontal
boundary aligning across the plains over the weekend and the
boundary will be the focus for showers and thunderstorms for
several days. Rainfall with this system looks to be fairly
widespread and amounts may potentially top one and two inches by
the end of the weekend. The frontal boundary is forecast to slowly
move southeast Sunday night into Monday, with rain chances
beginning to taper off in our northwest zones, but continue in the
southeast. Look for temperatures to trend cooler over the weekend
and into next week, dropping below normal by Monday.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 642 PM CDT Mon Sep 18 2017
Main impacts to aviation through this forecast period will be the
potential for fog Tuesday morning and breezy south winds Tuesday
afternoon.
Light southeasterly winds will be favorable for a radiation fog
to develop during the early morning hours. HRRR and RAP are coming
into line with the SREF for the most dense fog to be north and
east of the terminals. That said, I maintained a TEMPO group of
IFR visibility for KGRI because I am concerned that recent
rainfall may enhance the fog a bit into central Nebraska.
Nevertheless, fog potential will decrease as you move farther
westward, so I just 4SM visibility at EAR.
Whatever fog does develop will dissipate quickly as a stiff south
to southeasterly wind develops by late morning. Wind gusts during
the afternoon will likely range from 22 to 28kts.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Fire Weather Watch from Tuesday afternoon through Tuesday
evening for NEZ082.
KS...Fire Weather Watch from Tuesday afternoon through Tuesday
evening for KSZ005-017.
&&
$$
SHORT TERM...Fay
LONG TERM...Fay
AVIATION...Mangels
Area Forecast Discussion
National Weather Service Wilmington NC
951 PM EDT Mon Sep 18 2017
.SYNOPSIS...
Hurricane Jose will continue to lift off to the north leaving
dry and warm weather across the area through much of the week.
An increased rip current risk will linger along some beaches
due to continued swells. Hurricane Maria is expected to track to
the north offshore of the Carolinas during the middle of next
week but uncertainty remains. Maria is a powerful hurricane,
bringing increasingly strong rip currents and dangerous marine
conditions to the area late this week through at least early
next week.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 950 PM Monday...Hurricane Jose is essentially stationary
about 230 miles east of Hatteras Island. Aside from a light
northerly breeze and some cirrus streaming in from the east
there are no impacts on our weather from Jose. Temperatures have
fallen rather quickly this evening as some spots inland have
already decoupled from the boundary layer with calm winds noted.
Radiational cooling should drop temperatures into the mid 60s
for most locations overnight, with a little ground fog possible
in spots as dewpoints recover.
The biggest forecast challenge remains the potential for another
late night low stratus event to surge southward out of eastern
North Carolina. The 12 and 18Z runs of the GFS were quite
bullish with the potential, however the NAM and ECMWF were not
as they had low level winds backed just a little more westerly
which kept the low clouds north and east of ILM. The last couple
of HRRR runs do bring some low stratus into SE North Carolina
near sunrise. Although I earlier believed we might get through
the night without low clouds, after noting the current
observation up at Greenville, NC I am beginning to question
the premise of a clear late night/early morning for areas east
of Elizabethtown, Whiteville, and Oak Island.
Other than some increased cloud cover around daybreak in the
Cape Fear area, no significant changes were made to the forecast
with this evening update.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...Quiet conditions will continue for the
most part through the period. The mid level pattern will feature
a weak westerly flow that morphs into a decent trough late
Wednesday into early Thursday. The GFS and ECMWF are painting a
few showers in the area late Wednesday into early Thursday while
some of the other guidance is void of this activity. I did add
a slight chance of showers to address. No significant changes to
temperature guidance or forecast.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 1200 PM Monday...Persistent high pressure will be
reinforced from the north Fri and Sat. Did include a small risk
for a shower or thunderstorm Thu, before high pressure
strengthens across the area. Did include a small risk for an
afternoon shower or thunderstorm along the seabreeze Sat and
Sun.
Monday`s forecast will hinge to a large degree on the track and
strength of powerful Hurricane Maria and we will be watching
the tropics especially closely. Tropical cyclone Jose or its
remnants will be virtually stalled SE of New England late in the
week and may actually begin to drift S Fri and through the
weekend. Hurricane Maria is expected to be a powerful hurricane
as she approaches during the weekend. Her forerunner swell
energy will begin to be felt on the Carolina beaches late week
which will increase the breaking wave heights and rip current
risk. A high risk for rip currents is likely this weekend and
early next week. Much too early to have any confidence in a
track forecast for Maria as she approaches the southeast coast.
Some of the models continue to show interaction between Maria
and Jose early next week and Jose may play a part in the path
Maria ultimately takes as she gains latitude and approaches the
U.S. east coast.
Highs will be in the mid and upper 80s Thu and Fri and lower to
mid 80s thereafter. Lows will be mainly in the 60s.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 00Z...VFR conditions are expected up through 0800Z.
Patchy ground fog could develop in spots between 08-12Z, but
this potential appears low in all areas but the LBT airport
where low-level winds should be lightest and will offer the best
potential for visibility restrictions. Models also show another
night of low stratus developing across far-eastern North
Carolina, but unlike in at least the last three nights this
stratus cloud cover is not expected to make it into ILM, instead
remaining just north and east of the area.
Extended Outlook...Mainly VFR conditions through the period are
expected with the exception of a few hours of early morning low
clouds or fog most mornings through the period. The highest
risk of IFR conditions will be in the 0900-1200Z timeframe each
morning.
&&
.MARINE...
NEAR TERM /THROUGH TUESDAY/...
As of 950 PM Monday...4-6 foot seas are just barely hanging
onto the Cape Fear area waters. Even out at the Frying Pan
Shoals buoy the latest wave height was only 5.5 feet. Given the
direction of the swell it`s very likely larger seas continue on
the other side of the shoals, and the advisory will remain up
for now.
Hurricane Jose is essentially stationary about 230 miles east of
Hatteras. Shallow water on Capes Hatteras and Lookout are
blocking a good deal of the swell energy from reaching our area,
and shadowing from Cape Fear is further protecting the South
Carolina coastal waters this evening. Steady but diminishing
northerly winds are expected overnight with few additional
chances necessary to the forecast.
SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...A weak pressure pattern will continue
through the period across the coastal waters. Wind speeds will
be ten knots or less through the period. Wind direction will be
primarily from the southwest but a weak surface trough passing
through early Thursday will push winds to more of a westerly
direction at that time. Significant seas will be 2-3 feet.
LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 1200 PM Monday...The risk for Small Craft Advisory seas
is increasing this weekend. Weak high pressure will prevail
through the period but will become better established from the
north late week. Long period swell, the forerunners of powerful
Hurricane Maria, will begin to reach our waters during this
time. The swell energy looks to become significant Fri and Sat.
The swell direction will be from the SE. Guidance is showing
periods of around 15 seconds at Frying Pan Shoals with wave
heights increasing from 4 to 5 ft Fri to 6 to 7 ft Sat. The
swell will further increase Sun and Mon which will result in
higher wave heights.
&&
.TIDES/COASTAL FLOODING...
As of 300 PM Monday...The lower Cape Fear will see high astro
tides again with tonight`s high tide cycle this evening, and a
`coastal flood advisory` was needed for water levels almost a
half foot above the advisory threshold for downtown Wilmington.
Minor flooding will occur between 8pm-11pm tonight downtown, and
more coastal flood advisories are likely according to tidal
predictions through at least the first day of Fall, and
September 22nd at 2002Z this year Autumnal Equinox occurs.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...Coastal Flood Advisory until 11 PM EDT this evening for NCZ107.
MARINE...Small Craft Advisory for hazardous seas until 8 AM EDT Tuesday
for AMZ250-252.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...RJD
AVIATION...TRA
TIDES/COASTAL FLOODING...MJC
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1045 PM EDT Mon Sep 18 2017
.UPDATE...
Issued at 1045 PM EDT MON SEP 18 2017
Freshened up the near term grids to make sure they were on track
with the latest observations. Several locations in the far eastern
portion of the CWA have dropped near to or even below the
forecasted lows for overnight. This led to some adjustments in the
overnight lows and diurnal trends to better accommodate the
current trends. Also, the HWO and TAFs are giving dense fog
wording, but noticed it was not reflected in the grids. Went ahead
and added dense fog after 6Z, ranging from patchy to areas. All
changes have been published and sent to NDFD/web. A new forecast
package was sent out to reflect these changes and change to
overnight wording.
UPDATE Issued at 755 PM EDT MON SEP 18 2017
Forecast is on track so far this evening. Loaded in the latest
observations to make sure the near term grids were on track with
current conditions. Still a few isolated showers ongoing across
the far western portion of the CWA. Once these have tapered off,
will update the grids to remove the pre-first period rain
mention and sent out a new forecast package. All changes have been
published and sent to NDFD/web.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 435 PM EDT MON SEP 18 2017
20z sfc analysis shows weak high pressure in place over eastern
Kentucky though it is not effective in suppressing a few showers
now popping up over western parts of the Cumberland Valley. On
satellite, most of the area is seeing just small patches of cu,
but through the breadth of the Cumberland Valley, where the
showers are active, the clouds are more extensive and robust.
Plenty of sunshine for most of the area have sent temperatures up
into the lower 80s. Meanwhile, dewpoints are holding in the low
to mid 60s with the winds still light and variable.
The models are in fairly good agreement with the recent changes in
the mid and upper air patterns through the short term portion of
the forecast. They all now are a bit more hearty with the energy
that initially drifts through the weakening ridge this evening and
then even more so on Tuesday afternoon and evening. This latter
batch will lower heights and pool like a small trough between
periods of still rather weak ridging into Wednesday morning. Given
this agreement have favored a blended model solution along with a
good portion of specifics from the higher resolution HRRR and
NAM12 and a healthy dose of persistence - especially tonight and
early Tuesday morning.
Sensible weather will feature some widely scattered showers
through early evening - mainly over the western parts of the CWA.
a stray thunderstorm cannot be ruled out, as well. Otherwise, it
will be more of the same with clearing skies this evening and
cooling conditions leading to areas of fog - locally dense in the
river valleys for Tuesday morning. Look for the fog to dissipate a
bit quicker Tuesday morning as clouds move in from the west ahead
of a weak front. This will likely result in showers and
thunderstorms developing by early afternoon favoring the western
portion of the forecast area. The convection will die out in the
evening setting the stage for more fog development that night into
Wednesday morning - though limited by more clouds being around
through the night.
The CONSShort and ShortBlend were used as the starting point of
all the grids. Did make some adjustments to the temperature ones
each night based on terrain in anticipation of small to moderate
ridge/valley splits. As for PoPs, did tweak them for the diurnal
cycle peaking late afternoon and diminishing after sunset.
.LONG TERM...(Wednesday through Monday)
Issued at 306 PM EDT MON SEP 18 2017
An upper level ridge will amplify over the Ohio Valley through
the period continuing the unseasonably warm weather pattern for
our area. A weak upper trough trapped between Hurricane Jose and
the building ridge over the Mississippi Valley will cause the
potential for a few showers and storms Wednesday and Thursday.
That potential shifts to our southwest and withers as the upper
trough dissolves and surface high pressure builds southward
ensuring a dry weekend for our region.
Temperatures are expected to consistently top out in the low to
mid 80s each day through the period. Overnight lows are forecast
in the low 60s, then dropping into the upper 50s over the weekend
as drier air filters in.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 801 PM EDT MON SEP 18 2017
After another day and evening of VFR conditions, fog is expected
again tonight. Development will commence after 03z, starting in
the valleys, not likely impacting TAFS until after 06z. Fog
should be similar to the past several nights and be confined
mainly to the valleys, but still creep up into a couple of the
airport sites for a time, most likely near dawn. Have used a tempo
in a few of the TAFs for this concern. VFR conditions will then
re-establish themselves for the first part of the day tomorrow
after the fog dissipates in the morning. For the afternoon,
scattered showers and thunderstorms will move into the region from
the west, along with generally SCT CIGS between 3 and 4k ft.
Included VCTS in TAF sites between 18 and 20Z, though exact
timing/location and impacts of these storms is still low
confidence. Light winds are expected through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...GREIF
LONG TERM...ABE
AVIATION...GREIF/JMW
Area Forecast Discussion
National Weather Service North Platte NE
652 PM CDT Mon Sep 18 2017
.SYNOPSIS...
Issued at 309 PM CDT Mon Sep 18 2017
H5 analysis from this morning had a tandem of closed
lows over southern Canada. The first was over northern Ontario and
the second was off the coast of central British Columbia. Across the
lower 48, with the exception of the Pacific Northwest, a low
amplitude pattern was noted. Shortwave energy tracked through the
central plains overnight and led to a broad area of showers and
thunderstorms across the region. After beginning the day with broad
coverage of low cloudiness, skies have gradually cleared this
afternoon. Readings as of mid afternoon across western and north
central Nebraska were generally in the 70s.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 309 PM CDT Mon Sep 18 2017
In the short term, fog potential tonight, followed by fire
weather concerns Tuesday afternoon are the main forecast concerns.
For tonight: A trough of low pressure will deepen across eastern
Wyoming increasing southerly and southeasterly winds across
western and north central Nebraska. With low level cloudiness just
off to the east and light serly winds tonight, a decent setup
exists for the development of fog/stratus, especially over the
southern half of the forecast area. This notion is supported by
the latest NAM12 and 4KM NAM solns which push moisture west into
central and swrn Nebraska overnight. Did go ahead and insert some
patchy fog for the eastern sandhills and southwestern Nebraska. I
did not push the fog mention to areas of fog as the numerical
guidance and HRRR soln didn`t support that just yet. The surface
trough will slide east into the panhandle and northwestern
sandhills Tuesday morning. With surface heating, the fog and
stratus will push east and dissipate by noontime. By afternoon,
low pressure will begin to deepen over nern Colorado, producing
southwesterly winds and forcing a dry line into portions of
southwestern Nebraska. As of 21z Tuesday, the dryline, will lie
down roughly along highway 25 from Sutherland to Palisade. West of
this feature, temps will reach the lower to middle 90s with
minimum RH`s falling to 10 to 15 percent. East of the dryline,
RH`s will fall off to 15 to 25 percent across the eastern
panhandle and western sandhills. Winds on Tuesday will be
strongest east of the panhandle where a nice pressure gradient
will lead to breezy conditions across most of the forecast area.
Across the panhandle and western sandhills, winds will be lighter
as they will be under the influence of a pre frontal trough of low
pressure. With winds of 10 to 20 MPH and some gusts approaching
25 MPH and minimum RH`s of around 15 percent, decided to hoist a
red flag warning for zone 210 which will run from noon to 6 PM
MDT.
.LONG TERM...(Tuesday night through Monday)
Issued at 309 PM CDT Mon Sep 18 2017
Active pattern coming our way as a large upper level trough digs
south through the western portions of the United states. Our region
will remain on the eastern periphery of the upper trough with
southwest flow aloft to dominate through midweek. Then as the trough
digs farther south into the southwest Conus, a more south-southwest
flow aloft will develop for the last half of the week including the
weekend.
Still a small chance for thunderstorms Tuesday night across far
northern Nebraska along a cold front, but the better focus will
remain north in the Dakotas where better dynamics associated with the
upper level wave will be located. SPC has shifted the threat for
severe mostly out of our area, and agree with the better chances
remaining to the north.
The cold front will scour out the moisture for Wednesday through
Thursday night and expect dry conditions during this time. For
Friday into the weekend, rain/thunder chances will increase, as both
quality low level moisture and upper level dynamics become favorable
for precipitation development. As the flow aloft becomes near
meridional, south-southwest aloft, potential for several rounds of
showers and thunderstorms training over the same locations through
the weekend. WPC indicates the potential for up to 1.25 inches
across the panhandle, with near 4 inches possible farther east
across northern into central Nebraska. Will have to monitor for
potential heavy rain this weekend.
Highs will be warm through the end of the week, and then cool off
for the weekend as clouds and the threat for rain increase.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 624 PM CDT Mon Sep 18 2017
Latest satellite imagery shows a swath of high clouds moving
eastward across western NEB, otherwise fair conditions exist.
Primary concerns this TAF package are fog/stratus and LLWS
conditions. Mostly clear skies will prevail through the evening.
Stratus and fog become a concern early morning tomorrow and
current thinking is for stratus/fog to develop westward into north
central NEB and parts of southwest NEB. Current thinking is KLBF
terminal more likely to see impacts from fog/stratus than KVTN
thus its inclusion in the TAF. Thereafter conditions are
anticipated to improve mid-late morning.
Otherwise, LLWS conditions associated with a low-level jet is a
concern as it develops across far western NEB into SD tonight. The
area of concern for LLWS conditions is over northwest NEB and
northern NEB given forecast soundings and guidance. Elsewhere,
LLWS conditions are expected to be marginal or not be present thus
no mention in the KLBF TAF at this time, but will monitor and may
need to update the TAF if conditions or guidance warrant.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 6 PM MDT Tuesday for NEZ210.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Taylor
AVIATION...ET
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
929 PM CDT Mon Sep 18 2017
.UPDATE...
Minor update to extend the isolated thunderstorm mention to
encompass the far eastern zones through the remainder of the
evening hours. Current small but occasionally fairly robust
convective cores have continued to persist and even expand in
coverage this evening. They may continue right into the eastern
Rolling Plains. Given the trends, have expanded the mentionable
PoPs eastward this evening. More recent iterations of the RAP,
HRRR and TTU-WRF also indicate potential isolated activity
redeveloping further west over the South Plains tonight. Given
modest moistening seen upstream in the water vapor imagery, decent
residual elevated instability that will be in place and a
developing southerly LLJ, additional (albeit likely isolated at
best) convection appears possible late tonight into the early
morning hours Tuesday. Given this we have also added a minimal
thunder mention for much of the CWA in the 06-12Z time-frame. No
other significant adjustments were made to the forecast at this
time.
&&
.PREV DISCUSSION... /issued 632 PM CDT Mon Sep 18 2017/
AVIATION...
VFR conditions are expected through Tuesday. Isolated showers with
a bit thunder should remain south of the terminals this evening.
Without the cool post-convective air mass ala last night,
restrictions to visibility and/or ceilings are unlikely.
PREV DISCUSSION... /issued 320 PM CDT Mon Sep 18 2017/
DISCUSSION...
Two weak areas of surface convergence, one along the northern
borders of Garza to Stonewall counties and the other across
southeastern Briscoe county, and a dryline currently in eastern NM
will be the main areas of focus for potential convective
development later this afternoon and evening. The timing of
initiation should line up with a jet maxima pushing northeastward
out of Chihuahua. Currently the FA is located along the exit
region of the jet maxima which is aiding in some subsidence. Storm
chances should decrease after sunset as the jet pushes east of the
FA. Some storms could become severe and produce damaging winds up
to 70 mph and hail up to one inch. Rain chances will be low
tomorrow into Thursday and Friday as flow remains mostly zonal
aloft.
By late weak an upper low will dig southward across the western
CONUS placing the region back under southwesterly flow aloft. A
lee trough will allow surface winds to be out of the southeast
transporting Gulf moisture into the FA ahead of the approaching
upper low. Rain chances will increase from the west as the low
moves slowly towards the FA by Friday into Saturday. The 12z model
runs have slowed down the eastward progression of the upper low
which would delay the timing of lift moving into the region.
Previously models were showing decent lift pushing into the FA by
late Friday into Saturday but are now holding off until late
Saturday/early Sunday. Given the slower model guidance pops will
continue to be kept below the likely category with higher chances
favoring our northwestern zones. Chances will increase as a front
pushes southward into West Texas early next week. As ample
moisture will be in place and the low will be slow moving heavy
rain could very well be possible, but it is still too early to
tell. Temps, however, should be cooler and more fall like as the
front moves through and cloud cover remains.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
23/07
Area Forecast Discussion
National Weather Service Nashville TN
753 PM CDT Mon Sep 18 2017
.DISCUSSION...
Isolated late afternoon showers over the extreme north diminished
early this evening. An old and weakening gust front was observed
just south of OHX at 745pm, and had actually helped to cool
temperatures off a bit faster than the normal nocturnal trend
early this evening over parts of the extreme north. However,
expect temperatures over all of the Mid-State to stabilize mainly
in the upper 60s to lower 70s by midnight, and then slide on down
to the lower and middle 60s by dawn. Even though latest HRRR
doesn`t give us much prospect for showers for the remainder of the
night, can`t rule out some re-development late tonight, per
previous AFD. So, will leave pops and wx as they are.
No need for any changes to the forecast package at this time.
&&
.AVIATION...
00Z TAF DISCUSSION.
BNA/MQY/CKV/CSV...Surface and upper ridge have shifted some to the
east, allowing an upper trough to amplify and push across Middle
Tennessee tomorrow. This will produce a few more clouds and also
bring scattered POP`s to the mid state beginning late tonight
through much of tomorrow. Look for fog to develop once again
overnight, with forecast VSBY`s based largely on last night`s
observations.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 67 87 67 89 68 / 20 40 10 30 10
Clarksville 66 86 66 87 67 / 40 40 10 30 10
Crossville 59 80 61 81 62 / 10 40 10 40 10
Columbia 64 86 65 87 66 / 10 40 10 40 10
Lawrenceburg 64 85 65 86 66 / 10 40 10 30 10
Waverly 66 85 67 87 67 / 40 50 10 30 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......19
AVIATION........08
Area Forecast Discussion
National Weather Service Topeka KS
626 PM CDT Mon Sep 18 2017
...AVIATION UPDATE...
.SHORT TERM...(This evening through Tuesday)
Issued at 316 PM CDT Mon Sep 18 2017
Clouds are breaking out from west to east across the area as a
leading shortwave trof makes it exit eastward. Another weaker
wave is moving over western Kansas at this hour, and its axis
will likely be just to our east after midnight. A few models
suggesting an isolated shower or storm possible with this wave,
although the HRRR keeps much of it over central and southern
Kansas. Warmer temperatures already seen mixing down over western
and south central Kansas, and will be the main story for tomorrow
as those temps move eastward. Turning of the LLJ winds over this
front may generate a few storms toward morning over the eastern
counties, but again chances are low and have only carried a low
PoP at this time for that area. Biggest change will be the
temperatures tomorrow as the western areas hit middle 90s with
dewpoints in the 60s, and even in the east we rise to upper 80s
with dewpoints near 70, so it will feel quite warm and muggy
tomorrow as heat indicies near upper 90s to 100. One factor that
may help will be increasing winds, as breezy southwest winds of 15
to 20 with gusts to 30 develop tomorrow. Lows tonight fall into
the mid 60s.
.LONG TERM...(Tuesday night through Monday)
Issued at 316 PM CDT Mon Sep 18 2017
Wednesday time frame a weak boundary (hard to call it a cold
front) will likely push into the area during the day as an upper
level shortwave pivots through the Northern Plains around the main
low in Western Canada. Therefore, forcing for ascent resides
mainly to the north of the area. Also, per forecast soundings,
quality of moisture is likely not great in western portions of the
forecast area, but with higher dewpoints pooling along the
boundary as it slowly pushes southeast may come into play by late
in the day into early evening increasing MLCAPE values based on
some guidance up above 4,000 J/kg. Lack of deep layer shear along
with weak mid level lapse rates may be an inhibiting factor into
severe potential and coverage. So, probably just isolated to
scattered storms may form but with increasing isentropic lift into
the overnight time frame, associated with a weak LLJ, will keep
some showers going for the overnight period focused mainly into
the northern MO region extending back into very eastern portions
of the forecast area.
Quiet weather should prevail into the day Thursday until Saturday
late morning/afternoon time frame as a deep western CONUS trough
becomes more established and slowly shifts east drawing up gulf
moisture along a quasi-stationary/cold boundary on the eastern flank
of the trough. Dynamics and Kinematic forcing don`t look impressive
over the area, so any hazardous weather potential seems low, but
could be a wetter weekend overall.
Temps for the period will be upper 80s and low 90s for the week
before cooling back into the lower 80s over the weekend in
association with cloud cover and precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday)
Issued at 626 PM CDT Mon Sep 18 2017
There is some potential for elevated storms overnight, but models
seem to focus the better isentropic lift and moisture advection to
the southwest of the terminals. So chances do not look to be good
enough to include a mention in the forecast just yet. Chances for
LLWS also look to be weakening as the magnitude of the low level
jet is progged to be weaker than before. Opted to maintain a
mention at TOP where winds may be backed more and at MHK where low
level winds could still be a little stronger. Outside of any
thunderstorms impacting the terminals, conditions should be VFR
through the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Drake
AVIATION...Wolters