Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/20/19
Area Forecast Discussion
National Weather Service Burlington VT
1047 PM EDT Thu Sep 19 2019
.SYNOPSIS...
Strong high pressure will dominate regional weather conditions
through Sunday with fair and dry weather expected. Mild to warm
afternoon highs and seasonably cool overnight lows will be the
rule with generally light winds. The next chance of showers
arrives by Sunday night into Monday with the approach of a cold
front.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 1040 PM EDT Thursday...Dewpoints have continued to remain
a bit higher than forecast, so adjusted dewpoints up a bit
further the next few hours and then blended into the previous
forecast with some time-lagged HRRR and other high res guidance.
Otherwise, high cirrus clouds coming in with the forecast
remaining in excellent shape. Have a great night!
Previous Discussion...
A persistence forecast methodology will be used with this
package update with deep layer ridging up to 250 mb anchored
across the northeastern third of the nation over the next 42
hours. Outside some passing thin high clouds mainly clear skies
are expected and with the surface high center gradually edging
to our east over time air mass moderation will occur as synoptic
low level flow trends light southerly. Tonight`s lows should
reflect this, being not as cool as this morning - mainly upper
30s to lower 40s in the mountains and mid 40s to lower 50s in
the broad valleys. Corresponding highs on Friday should range
milder through the 70s with Friday night lows some 6 to 10
degrees milder than tonight - 50s. Enjoy!
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 241 PM EDT Thursday...Saturday will be the sunnier of the two
days this weekend with the upper level ridge axis directly
overhead. Temperatures will warm nicely under this deep layer
ridge given strong warm air advection which should yield
afternoon highs in the mid to upper 70s with readings in the
lower 80s in the Champlain and Saint Lawrence Valleys. The GFS
is trying to create some shower activity Saturday afternoon
which is by far the outlier and looks very unlikely given that
the dynamics will be well off to our north and west on Saturday.
Ended up increasing cloud cover slightly but kept PoPs at 0% as
subsidence should keep any shower activity at bay. Saturday
night is going to be very mild with southerly winds and clouds
increasing ahead of an approaching cold front. This should keep
overnight lows in the mid 50s to mid 60s.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 241 PM EDT Thursday...Sunday, for the most part, should be a
pretty nice day across the North Country albeit a touch on the windy
side. With the upper level ridge axis and the surface high beginning
to shift eastward, we will see the pressure gradient increase
throughout the day on Sunday. Winds won`t be too strong with winds
gusting in the 18 to 25 mph range. Southwesterly flow in the mid-
levels will strengthen the warm air advection across the region
which will yield even warmer temperatures on Sunday with highs in
the upper 70s to mid 80s. It may actually feel cooler on Sunday with
the stronger winds adding a bit of a "wind chill" to how it feels
outside. The approaching cold front appears it`ll be slower to
impact the region as the trough out west doesn`t look as robust as
it once did. This will slow the onset time of rainfall in the Saint
Lawrence Valley until sunrise on Monday before spreading eastward
throughout the day.
The rainfall on Monday still looks unimpressive with the main upper
level forcing remaining north of the international border. There
will be a nice ribbon of moisture of 1.5+" precipitable water values
but the lack of dynamics should produce less than optimal rainfall
rates. The southwesterly jet won`t be doing us any favors in the
Champlain Valley where it still looks like some shadowing could be
observed. Overall rainfall amounts still look much less than a
quarter of an inch but some of the western slopes of the Green and
Adirondack Mountains may do a little better. Showers will continue
through the day on Monday but taper off Monday night and exit the
region by Tuesday morning.
A return to deep layer ridging will develop on Tuesday but will be
rather short lived. This should yield another nice day across the
North Country with temperatures right around normal following the
cold front on Monday. The overall longwave pattern will become less
amplified heading into Wednesday which will prevent and large warm-
ups or cool-downs but it does bring rain chances back to the region
on Thursday as a strong shortwave traverses the northwesterly flow
aloft.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Through 00z Saturday...Water vapor and sfc analysis shows a
ridge both aloft and at the sfc across our taf sites. This will
result in vfr conditions with clear skies and light trrn driven
winds overnight. A brief window of ifr vis is possible at
mpv/slk around sunrise on Friday. Otherwise, light winds become
south/southwest at 3 to 7 knots on Friday as vfr conditions
prevail at all taf sites.
Outlook...
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. Chance SHRA.
Monday: Mainly VFR, with areas MVFR possible. Likely SHRA.
Monday Night: MVFR/IFR conditions possible. Chance SHRA.
Tuesday: Mainly MVFR, with areas VFR possible. Slight chance
SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...JMG
NEAR TERM...Haynes/JMG
SHORT TERM...Clay
LONG TERM...Clay
AVIATION...Taber
Area Forecast Discussion
National Weather Service Cheyenne WY
821 PM MDT Thu Sep 19 2019
.UPDATE...
Issued at 817 PM MDT Thu Sep 19 2019
Humidity has increased into the low 20 percent range across
southwestern Carbon County this evening. This allowed the Red Flag
Warning to expire on time at 8 PM. Updates have been sent.
&&
.SHORT TERM...(This evening through Friday)
Issued at 319 PM MDT Thu Sep 19 2019
Water Vapor imagery showed a large west coast storm system moving
across the great basin and intermountain west. Visible imagery
showed scattered cumulus towers developing along the laramie range
and areas of higher terrain across the western portions of
southeastern Wyoming. Surface obs showed a plume of low level
moisture sitting across the panhandle and far eastern Wyoming
with a cold front associated with the upper level impulse slowly
moving through far western Wyoming. These observations and short
term guidance suggest that isolated to widely scattered showers
and thunderstorms will develop across southeastern Wyoming over
the next few hours. HRRR forecasts continue to show a small
cluster of mainly elevated storms in proximity to the laramie
range with another more robust cluster across the southern
nebraska panhandle into northern Colorado. Some high rise guidance
keeps shower activity around with the cold front as it moves
through later this evening and overnight.
Temperatures should see a strong response to the front with highs
on Friday 10 to 15 degrees cooler than today. More widespread
shower and thunderstorm activity is expected Friday afternoon and
evening as the main upper level storm system moves overhead.
There will also be potential for severe weather mainly across the
Nebraska panhandle Friday afternoon and overnight with better
lift from the upper level system. Regional model soundings show
moderate instability with unseasonably high moisture across the
panhandle. Deep layer shear is supportive of organized convection
including supercells. The primary threats with any sustained
storms would be hail and strong winds. Models do show eventual
upscale growth across the panhandle overnight Friday.
Friday night into Saturday morning, the focus shifts to much
cooler temperatures and the possibility of the first freeze of the
year. Model guidance has continued to show the possibility for
freeze and borderline hard freeze conditions in some of the
western valleys of Carbon county. Overnight lows of 30 appear
common and given recent over estimation trends, lows in the high
20s for a few hours seem possible for well sheltered locations
Saturday morning. A Freeze Watch has been put in place for the far
western valleys from Friday night through Saturday morning.
.LONG TERM...(Saturday night through Thursday)
Issued at 204 PM MDT Thu Sep 19 2019
Medium and long range guidance has continued to show an active
upper level storm track developing this weekend and continuing
through next week. A second pacific trough behind this weekends
system is progged to dive across the CONUS with differing
solutions on the GFS and the EURO. The GFS shunts a shortwave
trough the central and southern CONUS early next week while the
EURO cutoff the same system over the 4 corners. While radically
different, both models keep the northern stream of the mid level
jet across Wyoming with the potential for some episodes of high
winds and an occasional shower. The majority of the forecast
appears to be dry but will likely remain active with weather
hazards mainly strong winds as more pacific troughs develop later
next week and into the upcoming weekend. Temperatures will likely
remain above average through the period before another stronger
cold front develops and moves through late next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 519 PM MDT Thu Sep 19 2019
VFR conditions will prevail for the KCYS, KLAR, and KRWL sites
this evening. Gusty south to southwest winds 20-30 knots will
continue until 20/04Z for Wyoming terminals. A stray shower is
possible near KCYS this evening, but left VCSH out of TAFs due to
low probability. High clouds will be present over the Nebraska
Panhandle in the late evening and overnight for terminals.
Included VCSH for KBFF near 20/05Z for the low chance of a shower
making its way into the Panhandle before dissipating. Expect
Nebraska Panhandle terminals at KAIA, KBFF, KCDR, KSNY to
experience breezy winds in the late evening from approximately
20/02Z until 20/06Z before decreasing. The focus will then
transition into Friday as an upper level system slowly approaches
the areas presenting gusty winds into the forecast once again.
&&
.FIRE WEATHER...
Issued at 319 PM MDT Thu Sep 19 2019
Gusty winds and low humidity have developed across far western
portions of zone 304. A cold front will move through later today
and early Friday bringing cooler conditions and better humidity
recoveries. This should limit the fire weather threat to the next
few hours before rain chances and colder temperatures arrive this
weekend.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Freeze Watch from late Friday night through Saturday morning for
WYZ111-113-115.
NE...None.
&&
$$
UPDATE...GCC
SHORT TERM...AL
LONG TERM...AL
AVIATION...BW
FIRE WEATHER...AL
Area Forecast Discussion
National Weather Service Duluth MN
650 PM CDT Thu Sep 19 2019
.UPDATE...
Issued at 650 PM CDT Thu Sep 19 2019
Updated for the 00Z Aviation discussion.
&&
.SHORT TERM...(This evening through Friday)
Issued at 316 PM CDT Thu Sep 19 2019
Mostly dry conditions will continue through the day Friday, with
a warm and humid air mass remaining in place.
Mostly clear skies are expected through the evening hours tonight
as high pressure will remain in control over the Northland, along
with a mid-level ridge axis overhead. There is a possibility that
a low-level inversion will build, per the RAP and NAM model
soundings, which will lead to increasing low clouds late tonight.
Some patchy fog should develop with the window of clearing skies
and light winds, leading to some patchy radiation fog
development. Overnight lows should fall into the lower 50s north
to the upper 50s to near 60 south.
Friday looks to be slightly more active compared to today as we
get some southerly return flow around the departing surface high,
which will help increase warm air advection. A weak shortwave
impulse will help keep mostly cloudy skies in place, along with
the warm and humid air mass. A gradually increasing theta-e ridge
will build along the warm air advection wing, increasing
instability to the tune of 1000 to 2000 J/kg of mixed-layer CAPE,
and dew point temperatures in the middle to upper 60s - quite
humid for this time of the year. Deep layer shear remains very
modest, so any thunderstorms that develop are not expected to be
severe. Any thunderstorms that do develop will likely be in the
afternoon and early evening hours when the instability will be
most favorable. Some uncertainty does exist with where these
thunderstorms will develop, but it seems most likely to develop
over central and north-central Minnesota. There will be an
easterly component to the flow, which should bring some cooler
temperatures along Lake Superior. Highs Friday will range from the
middle 60s along the North Shore to the upper 70s to near 80
farther inland. Southeasterly winds could be on the breezy side
over north-central Minnesota, where gusts between 15 to 25 mph
will be possible, especially in the late morning and afternoon
hours.
.LONG TERM...(Friday night through Thursday)
Issued at 245 PM CDT Thu Sep 19 2019
An upper level longwave trof will move from the lee of the
Rockies into the Northern Plains Friday night, while its
associated surface trof reaches the central Dakotas. This will
result in a southwest flow over the forecast area. A 40 knot low
level jet will combine with the omega ahead of the trofs, and have
pops increasing through the night. Much of northwest Wisconsin
will stay dry, however. The upper trof becomes positively tilted
on Saturday as embedded impulses lift through the area. The
surface trof moves into the eastern Dakotas during this time. Pops
continue to increase across the area in response. Thermodynamic
profiles suggest some strong, to possibly isolated severe, storms
are possible in the afternoon. MUCAPE values are 1500-2000 J/kg,
but lapse rates are marginal. Heavy rain is possible with
precipitable water values around 1.5 inches.
A pair of cold fronts will affect the region Saturday night. The
first will move through the entire area, bringing an end to the
storms, with some showers in its wake. The second moves through
northeast Minnesota late. Cooler air will follow behind the second
front with additional showers in the vicinity. The second front
moves through northwest Wisconsin on Sunday, while the upper longwave
trof moves overhead, with some additional showers. The upper trof
departs on Sunday night, pushing the cold front out of the area.
Lingered some pops Sunday evening as these features depart. Upper
level and surface ridging cover the region Monday and Tuesday
morning.
Tuesday afternoon finds a warm front lifting into the region from
the southwest as an upper level longwave trof moves into
Minnesota. There`s enough instability in the afternoon and evening
to generate a few thunderstorms. The warm front exits Tuesday
night as a cold front moves into northeast Minnesota late with
some additional showers. The cold front will move slowly through
the rest of the region on Wednesday and have lingered some pops in
the vicinity of the front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 650 PM CDT Thu Sep 19 2019
A ridge of high pressure has produced relatively quiet weather as
of issuance time, with all sites VFR. Fog is expected to develop
at some sites late tonight, with visibilities and even stratus
expected to develop at KDLH, KHIB and KHYR, with conditions
dipping into MVFR/IFR conditions overnight. KINL is less likely to
develop this, and have left this sites VFR for now, but some MVFR
fog is possible and may have to add that later. KBRD will have
more clouds, and have put in only MVFR visibilities. A strong
low pressure system developing over the high plains may cause
showers and thunderstorms to develop over west central MN, which
may bring showers into KBRD in the 14z-22z time range, along with
some MVFR ceilings. This approaching low pressure system will
cause stratus and/or fog to develop and stream in off Lake
Superior for KDLH toward the tail end of the TAF period. Models
may be too agressive on this for now, so have left off, but will
revisit with the 06z set.
&&
.MARINE...
Issued at 245 PM CDT Thu Sep 19 2019
Other than some patchy fog tonight, no hazardous marine
conditions are expected in the next 48 hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 70 59 72 / 10 10 30 80
INL 53 78 64 73 / 0 20 60 80
BRD 59 80 66 74 / 10 30 60 80
HYR 59 80 65 75 / 10 10 10 80
ASX 56 77 61 77 / 0 10 10 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...LE
SHORT TERM...JTS
LONG TERM...GSF
AVIATION...LE
MARINE...GSF
Area Forecast Discussion
National Weather Service Quad Cities IA IL
753 PM CDT Thu Sep 19 2019
.UPDATE...
Issued at 753 PM CDT Thu Sep 19 2019
Radar images over the past hour have shown scattered showers
developing over northwest Illinois, mainly In Stephenson county,
with more recent activity along the I-88 corridor from the Quad
Cities to Sterling. These appear to be occurring along weak
boundaries from convection earlier today, triggered by a weak
upper level shortwave axis showing up on the 00Z RAP analysis from
central WI south-southwest along the MS River. With relatively
stable mid level lapse rates (4.8 deg C/km 700-500 mb lapse rate
on the 00Z KDVN sounding), these should remain just showers and
trend eastward out of the area with the upper forcing early this
evening.
Through the rest of tonight, forecast confidence is low in the
potential for thunderstorms and heavy rain. While there is indeed
plenty of moisture, as evident by the 1.74 PW on KDVN 00Z
sounding, forcing remains lacking. In the near term, there will be
shortwave ridging following the current trough, an initial weak,
low level jet pointing more toward areas west of the MO River and
a lack of focused low level convergence in the forecast area.
Recent runs of the HRRR have backed off to now having only
isolated showers overnight then widely scattered activity after
sunrise.
Have updated the forecast for a dry evening, outside the isolated
showers early in northwest Illinois. Overnight, will keep only
low pops for scattered showers and thunderstorms along and north
of the I-80 corridor well after midnight into early Friday
morning. Heavy downpours will still be possible, but lacking any
strong signal supporting an organized MCS or back-building storms,
the potential for flash flooding looks low tonight.
&&
.SYNOPSIS...
Issued at 311 PM CDT Thu Sep 19 2019
18Z surface data has a weak boundary from the morning storms running
from north central Illinois, to near Quincy and then across northern
Missouri. Dew points were in the 60s from the Great Lakes into the
northern Plains with 70s from the Ohio Valley into the central
Plains down to the Gulf Coast.
&&
.SHORT TERM...(This Evening through Friday)
ISSUED AT 311 PM CDT Thu Sep 19 2019
Through sunset isolated showers and possibly a thunderstorm will
continue before dissipating.
Quiet conditions are then expected from sunset through mid-evening
across the area. Attention then turns to the late evening and
overnight hours.
The remnant boundary from the morning storms will likely be the
focus for new storm development tonight.
Trends from the very short term models suggest isolated showers and
storms should begin developing by late evening just south of I-80
and should increase in areal coverage through sunrise Friday.
The potential is there for another round of heavy rain given PWATs
are around 2 inches which is in the 99th percentile of atmospheric
moisture.
At this time no new flash flood watch will be issued. However there
is a very real possibility that a new flash flood watch will be
needed. The overall scenario will be one of nowcasting. That is we
will have to watch and see where storms develop and how they evolve
over time.
Right now any area from the I-80 corridor on north may be at risk
for heavy or excessive rainfall.
For Friday, storms that develop overnight will persist into the
morning hours with the northern half of the area favored for rain.
The risk of heavy rain will also be there with any storms during the
morning.
By late morning and into the afternoon the nocturnal storms will
dissipate and there may be a brief period of quiet weather. Isolated
diurnal storms should begin developing across the area by mid to
late afternoon.
.LONG TERM...(Friday Night through Thursday)
ISSUED AT 311 PM CDT Thu Sep 19 2019
Synoptic and mesoscale models both accurately depict a excessively
moist air mass with persistent lift will be found over the
Midwest through the end of next week. This pattern will not likely
result in rain in every period, but it will frequently provide
rainfall chances, and all of those seem to contain the threat of
heavy rainfall. The airmass in place, or the once advecting into
our region has been consistently forecast with PWAT values around
2 inches. That is always a signal for heavy rainfall, and in this
case, it is solidly in the 99% percentile, or about 200% of
normal. That`s not mesocale feedback, but the synoptic set up!
The tropical connection is a given, as it`s already in place as
Imedla`s remnants are interacting with our Midwestern moist
advection, this is what happened last night to our west and north,
and eventually into our north 1/2 this morning. That process should
not break down during periods of moist advection, until Sunday
evening. So, this looks like a slam dunk in needing a Flash flood
watch, but with the short term offering up a more mesoscale areal
extent of flash flooding, I am not inclined to issue an
exceptionally long lead time watch through the weekend at this
point. Though one could certainly be issued tomorrow for Friday
night through Sunday afternoon.
I am not overly excited about severe weather in this pattern, as the
extensive moist low levels are likely to become filled with low
clouds through the end of the event, and this should limit low level
CAPE. Like a typical tropical air mass, while we won`t have
explosive CAPE, we may well have in inexhaustible supply of "skinny
CAPE" with the atmosphere very close to the moist adiabatic profile.
The ability to generate cold pools will not be efficient, due to
this expected profile. I expect the severe weather to be tied
directly to areas of low level convergence, which at this point,
appear mainly to the southwest of Iowa.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 625 PM CDT Thu Sep 19 2019
VFR conditions will prevail this evening, then there will be a
chance for showers and thunderstorms late tonight and early Friday
morning at all sites. Forecast confidence is low on where this
axis of rain and thunderstorms will setup, thus only prob30
wording was used. Otherwise, the very moist atmosphere may lead to
fog and MVFR conditions, include at MLI, DBQ and CID late tonight.
There is a low potential that fog could result in conditions as
low as IFR, especially at DBQ toward sunrise. Isolated showers and
thunderstorms will be possible for much of Friday, but the
probability of occurring is too low to include in the forecasts
and VFR conditions with light east to southeast winds will
be the rule.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...Sheets
SYNOPSIS...08
SHORT TERM...08
LONG TERM...Ervin
AVIATION...Sheets
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
911 PM CDT Thu Sep 19 2019
.UPDATE...
Very quick update to the ongoing forecast mainly to trend the
forecast to the current radar observations. Severe thunderstorms are
ongoing across northern Bexar and western Guadalupe Counties. PoPs
have been focused on this storm complex through midnight. PoPs after
midnight are a blend of the high resolution models which do show some
light showers overnight across much of the area. Hourly weather
grids have also been adjusted to reflect current trends. The rest of
the forecast is on track.
&&
.PREV DISCUSSION... /ISSUED 644 PM CDT Thu Sep 19 2019/
AVIATION...
Scattered showers and thunderstorms continue across parts of South
Central Texas this evening. While this activity has pushed south of
AUS, outflow boundaries continue to spark off showers and storms
further south around BAZ (New Braunfels). These boundaries should
sag south towards SAT/SSF through 04z and so the TEMPO for -TSRA has
been maintained to cover the potential for a few small cells
developed through the evening hours. Winds behind the boundaries has
generally switched from southeasterly to east/northeasterly for a few
hours. Will maintain VRB winds in those TEMPOs as SAT/SSF as the
boundaries and possible storms approach. After seeing a brief shower
near the terminal earlier this evening DRT should remain dry through
the night.
Overnight tonight high resolution models do maintain a few scattered
showers during the overnight hours as moisture remains high across
the area and various surface and upper level boundaries provide just
enough lift for activity to continue. For this reason VCSH was kept
in the I-35 terminals. With a more active low level jet overnight
stratus is also expected to develop after 06z at AUS/SAT/SSF and last
into Friday morning. By 17z skies should begin to lift to VFR, but
winds will pickup out of the southeast and be gusty during the day on
Friday.
PREV DISCUSSION... /ISSUED 320 PM CDT Thu Sep 19 2019/
SHORT TERM (Tonight through Friday Night)...
Showers and thunderstorms continue to develop over the Hill Country,
portions of the I-35 corridor near Austin, then into the Highway 77
corridor. The HRRR and Texas Tech WRF seem to have a decent handle on
the current radar trends and have generally followed their solution
for the afternoon hours. This will place the best chance of rainfall
generally along a Kerrville to Fredericksburg to Austin to La Grange
line for the next few hours. We should then see some additional
activity gradually work southward to near or just north of San
Antonio through the early evening hours. Given the slow movement of
these showers and storms along with above normal moisture levels, a
few spots may be vulnerable to some very localized flooding. However,
it will likely take multiple rounds of heavy rains to promote a
flood threat.
For this evening, we will keep a chance of showers and storms in the
forecast for areas north of a Leakey to Floresville line. Rain
chances will be favored for areas east of I-35 as this region will
remain in proximity to higher moisture levels. Through the overnight
hours, we expect a gradual decrease in activity, especially over the
Hill Country and I-35 corridor. We will need to keep an eye on our
eastern zones along the Highway 77 corridor as some of the hi-res
members show additional development through tonight.
On Friday, we will see another round of above normal temperatures
across the region, with highs in the 90s to near 100 degrees. We will
keep a chance of rain in the forecast for areas generally along and
east of I-35 given leftover outflow boundaries, above normal moisture
and daytime heating.
LONG TERM (Saturday through Thursday)...
The forecast for the upcoming weekend will call for above normal
temperatures across all of south central Texas as the subtropical
ridge centered over the southeastern U.S. expands across the Gulf of
Mexico into Texas. We should see enough residual moisture across the
region to allow for the development of mainly isolated showers and
thunderstorms for areas generally along and east of the I-35
corridor.
Early next week, the medium range models still show an upper level
system over the desert southwest, but differ greatly with the
progression of this system. The GFS continues to remain fastest with
this system, while the ECMWF and Canadian are much slower and show a
closed low lingering over the desert southwest into Wednesday. For
now, we will continue to side with the ECMWF solution as it has shown
better run- to-run consistency. We will continue to mention a very
low chance for showers and storms through the middle of next week,
but overall confidence is low at this time. Temperatures will also
continue to remain above normal with widespread highs in the 90s and
lows in the upper 60s and 70s.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 76 96 75 94 74 / 30 20 10 20 0
Austin Bergstrom Intl Airport 76 95 74 94 72 / 30 30 10 20 0
New Braunfels Muni Airport 75 95 74 94 73 / 40 20 10 20 -
Burnet Muni Airport 74 93 73 91 71 / 30 10 - 10 0
Del Rio Intl Airport 78 98 77 97 76 / 10 - - - 0
Georgetown Muni Airport 75 94 74 94 72 / 30 20 - 10 0
Hondo Muni Airport 76 99 75 97 73 / 30 - 10 10 0
San Marcos Muni Airport 75 96 73 94 72 / 40 20 10 20 0
La Grange - Fayette Regional 76 94 75 93 73 / 40 40 - 30 -
San Antonio Intl Airport 77 96 77 94 75 / 40 10 10 20 -
Stinson Muni Airport 78 96 77 94 75 / 30 10 10 20 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Aviation...Huffman
Short-Term/Long-Term...Treadway
Area Forecast Discussion
National Weather Service North Platte NE
629 PM CDT Thu Sep 19 2019
.SHORT TERM...(This evening through Friday night)
Issued at 250 PM CDT Thu Sep 19 2019
Forecast concern for tonight will be the potential for locally
heavy rainfall across portions of southwest Nebraska. Strong warm
air advection occurring at the surface across western and central
Kansas this afternoon, where south winds are gusting to 20kt and
temperatures near 93 degrees. Latest CAMs models indicate a few
clusters of thunderstorms developing in western Kansas late this
afternoon and early evening. A few models, including the NAM Nest
and NMM show develoment northward into southwest Nebraska this
evening. the latest HRRR and RAP models are also generating
convective QPFs. Still, given the model differences, and some
models indicating dry this evening, confidence is below average on
the location. However, anomalously high atmospheric moisture will
be available, where any thunderstorms which do develop will be
capable of producing rainfall rates above an inch per hour. WPC
has a marginal risk for excessive rainfall across southwest
Nebraska tonight. In addition, SPC has a Marginal Risk for severe
storms this evening across southwest Nebraska, with large hail and
damaging winds possible. A few lingering showers and
thunderstorms will be possible into the overnight hours. Lows
tonight will remain quite mild for this time of the year with lows
ranging from the lower 60s across the west to the upper 60s
across the northeast.
On Friday into Friday night, the main concern will be the threat
for isolated/scattered strong to severe thunderstorms late Friday
afternoon into Friday night.
An upper level trough will begin to lift northeast into the
Northern and Central Plains on Friday. Models agree on scattered
showers and thunderstorms during the day to move northward well
ahead of the approaching cold front. A few of the thunderstorms
could be strong to briefly severe. While brief heavy rainfall is
possible during the day, the potential for any flooding is low.
Going into Friday evening, the cold front will be the main forcing
for showers and thunderstorms. SPC currently has a Slight Risk
north of a line from Oshkosh through Thedford and Butte, while a
Marginal Risk covers the rest of the CWA. Damaging winds, large
hail and heavy rainfall will be the primary threats for Friday
with the greatest risk being across the northeast Panhandle and
northwest Nebraska. As the storms progress eastward through the
area, we will also see a threat for heavy rainfall. WPC has a
Slight Risk for excessive rainfall across extreme north central
Nebraska with a Marginal Risk extending south to a line from
Oshkosh through O`Neill. for these areas, total rainfall amounts
exceeding 0.5 inches are expected, with as much as 1-2 inches
across portions of north central Nebraska possible. The cold front
and associated system will progress east fairly quickly and should
limit how much rainfall occurs. But, given how saturated the area
already is, localized flooding or flash flooding will be possible.
.LONG TERM...(Saturday through Thursday)
Issued at 250 PM CDT Thu Sep 19 2019
Dry with cooler temperatures behind the front on Saturday with a
mostly sunny sky. Highs from the upper 60s to low 70s northwest
Sandhills, to the upper 70s southeast. A breezy northwest wind
through the day. The dry conditions will be short lived for portions
of southwest Nebraska as precipitation chances increase once
again Saturday night. This will be aided by a strong upper jet
developing across western Kansas into eastern Nebraska as the base
of the upper trough swings through the region.
Sunday through Monday will remain dry across the area as upper level
ridging develops. Highs warm to around 80 Monday. An upper trough
will cross the Central Rockies on Monday, and the Northern and
Central Plains Monday night into Tuesday pushing a cold front
through the region. Only a 20 to 30 percent chance across
southwest into central Nebraska.
A closed upper low over Hudson Bay Canada will bring upper level
troughing into the Great Lakes Wednesday night into Thursday. This
will bring seasonable highs from the upper 60s to mid 70s and a
drier airmass to the region. Lows in the mid 40s to low 50s by
Wednesday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 628 PM CDT Thu Sep 19 2019
Thunderstorms will be possible in the vicinity of KLBF terminal
through 02z this evening. Most of the activity will pass off to
the southeast of KLBF with some high dense cloudiness in
association with the thunderstorms. Overnight, expect some low
level wind shear at 2000 FT AGL around 40 KTS. For Friday, expect
mostly clear skies with some scattered clouds 15000 to 20000 FT
AGL. For the KVTN terminal: Skies will be mainly clear over the
next 24 hours. Low level wind shear will be possible overnight
with 45 KTS expected 2000 FT AGL.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...Buttler
Area Forecast Discussion
National Weather Service Marquette MI
805 PM EDT Thu Sep 19 2019
.SHORT TERM...(This evening through Friday)
Issued at 330 PM EDT THU SEP 19 2019
RAP analysis shows an upper-level ridge over the Great Lakes and
Ohio River Valley as a trough digs south across the western CONUS. A
surface ridge of high pressure remains locked across the mid-
Atlantic through New England as a weak surface trough pushes through
Upper Michigan. A shortwave across WI this morning with ample
moisture transport ahead produced quite the line of rain and
thunderstorms this morning. Places in Menominee County received as
high as 5 to 6 inches based on radar estimates with the highest
observed report at 5.5 inches.
For tonight, winds will relax as a ridge of high pressure takes
over. Winds will turn slightly from the north overnight, creating
additional upslope flow. Expect fog to develop tonight with residual
low-level moisture and upslope flow tonight. By tomorrow morning,
low clouds and fog will be prevalent through Marquette County and
the higher terrain through central Upper Michigan. There will remain
a slight chance of showers and thunderstorms from Menominee County
along Lake Michigan into eastern UP through early tonight as a weak
shortwave continues north through Wisconsin. RAP soundings show a
few hundred J/kg of CAPE midnight, though much of the forcing has
ended.
By tomorrow, residual moisture will keep skies on the cloudy side
with some clearing late. The airmass will remain humid with limited
mixing. Temperatures will remain similar to this afternoon, but have
lowered them slightly given the forecasted low clouds through much
of the day.
.LONG TERM...(Friday night through Thursday)
Issued at 302 PM EDT THU SEP 19 2019
Friday evening, a broad eastern CONUS ridge and western CONUS trough
will be in place, with a somewhat disorganized area of weak to
lift generated by WAA and spotty PVA lifting northeastward
out of the central Plains towards the Upper Great Lakes. Relatively
unidirectional SWerly flow through the column will increase
through the day and pump deep moisture into Upper MI with sfc
dewpoints Saturday well into the 60s and PWats upwards of 1.5-1.75".
Afternoon wind gusts of 20-30 mph and locally higher are expected.
At this time, models are in relatively good agreement that there
will be little to no large scale forcing for ascent reaching the UP
through the day Saturday. Thus, only a couple of spotty showers and
perhaps a thunderstorm are expected at least through the early
afternoon. Instability should build to about 1000 J/kg, with
isolated pockets possibly approaching 1500 J/kg if some sunshine is
able to break through. Effective shear will also build through the
afternoon to 25-30 kts. But with a lack of forcing to speak of,
widespread thunderstorm development appears unlikely until later
in the afternoon over the west.
While precip chances will increase through the evening and
continue overnight as the forcing arrives, the cold front will
likely traverse the UP too late in the diurnal cycle for much
concern of severe weather. That said, in addition to the main threat
of heavy rainfall, isolated gusty winds or large hail will be
possible Saturday night. Precip will continue over the east Sunday
morning but by the afternoon, the system should be moving out,
leaving a cooler, drier airmass over the UP that is much more
seasonal for late September.
The large scale pattern will become more progressive early next
week. Mid-level ridging will briefly build in Monday afternoon
through Tuesday morning and allow for a quick return to warmer
temps but a deep trough will begin to dig down southeastward out of
Canada late Tuesday through Wednesday that will likely bring
additional precip chances midweek and a shot of cooler air for late
next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 804 PM EDT THU SEP 19 2019
MVFR conditions at KSAW are expected to prevail through this
evening. Otherwise, with light winds and abundant low level moisture
lingering over the region, expect fog and/or low clouds to develop
overnight at all terminals. Confidence in the timing and density
is still limited, so only IFR conditions were mentioned. Daytime
heating on Friday is expected to bring improvment to VFR by mid
morning.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 330 PM EDT THU SEP 19 2019
Winds below 20 knots expected through Friday as southerly winds
around 25 knots develop on Saturday afternoon. These winds will veer
westerly by Sunday morning remaining around 25 knots, up to 30
knots. As a cold front moves through winds become northwesterly with
gusts up to 25 knots through Monday. Winds will relax below 20 knots
until southwesterly winds on Wednesday afternoon gust up to 25
knots. Otherwise fog will remain possible through Friday as this
warmer, moist air mass remains over Lake Superior. Fog chances will
dwindle after the cold front this weekend.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JAW
LONG TERM...KCW
AVIATION...JLB
MARINE...JAW
Area Forecast Discussion
National Weather Service Norman OK
1048 PM CDT Thu Sep 19 2019
.DISCUSSION...
&&
.AVIATION...
MVRF level ceilings are expected to form and spread south to north
over most TAF sites by Friday morning. Rain chances increase by
mid-day in southern Oklahoma and areas to the south with scattered
thunderstorms. Southeast winds will continue.
&&
.PREV DISCUSSION... /issued 911 PM CDT Thu Sep 19 2019/
DISCUSSION...
Near term updates...
1. Increase POPs across far western Oklahoma to account for
weakening convection crossing the OK/TX border.
2. Delay rain chances slightly across southeast Oklahoma.
Convection across the Texas Panhandle continues to weaken this
evening. Additional storms are forming along an outflow boundary
but this should mainly impact areas to our west.
An isolated showers has recently developed near Sparks. RAP
sounding indicate a relatively thin cloud layer around
750mb with just enough positive area for precipitation. The clouds
and perhaps precipitation will continue to lift northwest
through the evening.
A deeper saturated layer is expected overnight, but only shallow
convection may be realized because of an inversion. It appears
better rain chances overnight will be across southeast, south
central, and perhaps central Oklahoma.
PREV DISCUSSION... /issued 703 PM CDT Thu Sep 19 2019/
DISCUSSION...
AVIATION...
MVRF level ceilings are expected to form and spread south to north
over most TAF sites by Friday morning. Rain chances increase by
mid-day in southern Oklahoma and areas to the south with scattered
thunderstorms. Southeast winds will continue.
PREV DISCUSSION... /issued 248 PM CDT Thu Sep 19 2019/
DISCUSSION...
Seasonal average temperatures and intermittent rain chances continue
to highlight the forecast period. Currently there are no reasons to
anticipate a high-impact rain event that may threaten weekend plans,
but chances for at least hit-and-miss rain do exist.
Isolated/scattered convection has again developed over the Texas
Panhandle in vicinity of a surface trough. CAMS show this activity
pushing toward western Oklahoma/western north texas, but
probabilities for it to actually make an impact on the forecast
area are probably limited to 30 percent. That said, marginally
sufficient instability/shear has supported isolated severe cells,
so will monitor.
The remnants of Tropical Depression Imelda will move north and begin
to affect the Arklatex/southeastern Oklahoma area in earnest
tomorrow. This warrrents 70-80 percent PoPs. Will monitor for heavy
rainfall potential, but better prospects for flooding threat appear
to remain southeast of the forecast area. Most models depict a bit
more robust eastward push of convection from west Texas into western
Oklahoma/western north Texas late Friday night/Saturday morning.
Have increased rain/storm chances there into the 40-50 percent
range. Prospects for severe weather with these storms appears low,
but there will be a marginal risk primarily for damaging winds.
Rain/storm chances appear to increase again Sunday. This as a well
defined shortwave trough translates over the northern/central Plains
and helps push a front southward into Oklahoma. Current indications
suggest northeastern and central Oklahoma will be favored.
Spread in the medium range solutions remains with respect to the
evolution of a more notable southern stream upper air low/trough
early next week. Saw no notable predictive signals to support
deviating from model blends at this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 69 82 71 85 / 20 20 30 30
Hobart OK 69 89 71 89 / 10 30 50 30
Wichita Falls TX 70 91 71 91 / 10 50 30 20
Gage OK 65 87 69 89 / 60 30 40 30
Ponca City OK 68 79 70 83 / 10 30 30 50
Durant OK 70 87 71 89 / 60 70 30 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
06/09/09
Area Forecast Discussion
National Weather Service Shreveport LA
918 PM CDT Thu Sep 19 2019
.UPDATE...
Just sent out a quick update to adjust pops areawide. Still
holding to high pops across northwest Louisiana overnight based on
HRRR guidance and proximity of upper-trough to the ArkLaTex.
Otherwise, will likely experience winds bordering Lake Wind
Criteria on Friday but will wait on 00Z model data before
finalizing decisions. /05/
&&
.PREV DISCUSSION... /issued 638 PM CDT Thu Sep 19 2019/
AVIATION...
Conditions to deteriorate overnight as ceilings become MVFR/IFR
areawide after 20/03Z. Additionally, widespread showers will
continue overnight with VCSH conditions possible across area
terminals. Ceilings to gradually improve to VFR by 20/18Z with
east to southeast winds around around 10 knots increasing to 10 to
15 knots on Friday with gusts to 25 knots across mainly east
Texas terminals. /05/
PREV DISCUSSION... /issued 400 PM CDT Thu Sep 19 2019/
SHORT TERM.../Today through Friday Night/
As weak inland tropical systems typically do, Imelda has presented
immense forecast challenges in terms of amounts and placement of
heavy rainfall. Fortunately for us, rainfall rates have been mostly
light where rain has fallen and haven`t resulted in any flooding
issues. The same cannot be said for much of SE Texas where immense
flooding has occurred with over 30 inches of rain in some isolated
areas. As the remnants of Imelda continue to slowly lift northward,
additional rainfall across our region is expected to remain quite
manageable and so the Flash Flood Watch has been cancelled for
those areas in East Texas and Northwest Louisiana where it was in
effect. Additional rainfall amounts of 1-3 inches will be possible
across our western locations with lighter amounts expected farther
east through Friday night.
The trends will be for showers and thunderstorms to gradually
expand northward through the remainder of tonight into Friday with
convection tapering off late Friday and especially Friday night.
Temperatures will continue to run below seasonal averages through
the short-term period with the overcast conditions and periods of
rainfall. Overnight lows will generally range from the upper 60s
to lower 70s while daytime highs on Friday are expected to mainly
run in the lower to mid 80s.
/19/
LONG TERM.../Saturday through Thursday/
The remnants of Imelda will be a thing of the past by Saturday with
her moisture pulling north toward a frontal zone in the Central
Plains and Midwest. Lingering boundary layer moisture could still be
enough to spur some very isolated afternoon convection, but a more
dominant upper level ridging influence will be providing some non-
favorable subsidence to the troposphere by that time. Conditions
will otherwise be muggy with temperatures at least slightly above
normal.
We still expect the aforementioned cold front to drop toward the
region on Sunday, probably making it into far northern zones of the
Four State region Sunday night into Monday before stalling. The
general model consensus on this frontal progression into northern
zones has improved somewhat in the past 24 hours. Correspondingly,
chances of rain associated with the front have increased some Sunday
night into Monday in northern zones, although chances are still
mainly below 40 percent and the potential for impactful or hazardous
weather remains quite low. There is some potential this front makes
enough inroads into the region to bring back at least isolated
convection for all areas by Tuesday and Wednesday of next week,
especially if a big upper disturbance coming into the southwestern
CONUS early next week does not get cut off from the westerlies. But
the latter stipulation is a big question mark right now as model
consensus in this regard is not good. If the disturbance does manage
to not cut off from the flow (and remain locked in the southwest
CONUS), then rain chances for portions of the region could go up
considerably around Wednesday to Thursday of next week. Conversely,
if the disturbance does not head this way then anticipate dry
conditions and a further trend back toward unseasonable warmth.
/50/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 70 84 72 90 / 80 60 10 10
MLU 70 85 69 91 / 60 60 10 10
DEQ 68 81 70 87 / 70 80 40 10
TXK 68 80 71 86 / 80 80 30 10
ELD 68 81 69 90 / 70 60 20 10
TYR 70 85 72 89 / 70 70 10 10
GGG 70 84 71 90 / 80 70 10 10
LFK 71 84 72 89 / 60 60 10 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
05/19