Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/07/16
Area Forecast Discussion
National Weather Service Tucson AZ
844 PM MST WED JUL 6 2016
.SYNOPSIS...Isolated to scattered afternoon and evening
thunderstorms will prevail mainly east to south of Tucson through
Friday. A few thunderstorms may occur across the White Mountains and
far southeastern sections Saturday, then dry conditions area-wide
Sunday into next Wednesday.
&&
.DISCUSSION...Showers and thunderstorms developed pretty much as
expected this afternoon with the bulk of the activity across Santa
Cruz and Cochise counties with the northwestern edge right in
Tucson. A few of the storms dropped up to about 1.25 inches of rain
in localized spots which created some minor flooding issues. The
latest KEMX radar imagery shows all the remaining thunderstorms are
now over Sonora with areas south and east of Tucson seeing
considerable debris cloudiness and perhaps a few sprinkles or very
light showers. Expect this activity to continue to diminish over the
next few hours. There is a clear distinct remnant circulation from
the MCV we`ve been looking at all day across Central/Northern Sonora.
This is progged to move northeast in the southwest flow aloft into
Cochise County early Thursday morning. Thus, will continue to depict
slight chance PoPs overnight into Thursday morning south and east of
Tucson. Enough moisture remains from Tucson eastward for isolated to
scattered showers and thunderstorms Thursday afternoon. Have already
sent a couple of updates this evening to account for latest trends
overnight. Otherwise, forecast looks in good shape. See previous
forecast discussion below for additional information.
&&
.AVIATION...VALID THRU 08/06Z.
A slight chance of -TSRA/-SHRA is possible for
KDUG/KOLS terminals overnight into Thursday morning. By Thursday
afternoon, expect isolated to scattered -SHRA/-TSRA from Tucson south
and eastward to the New Mexico/international
borders this evening.
Otherwise, clear skies to scattered clouds above 20k ft msl will
prevail west to northwest of KTUS thru Thursday afternoon. Surface
winds will be mainly light into Thursday morning, becoming
wly at 10-15 kts with gusts to 20 kts Thursday afternoon before
tapering off Thursday evening. Aviation discussion not updated for
TAF amendments.
&&
.FIRE WEATHER...Isolated to scattered showers and thunderstorms will
occur from Tucson eastward and southward through Friday. A
few thunderstorms may occur across the White Mountains and far
southeastern sections Saturday, then dry conditions will prevail
area-wide Sunday through next Wednesday. Apart from brief gusty
thunderstorm outflows, 20-foot winds will generally be terrain driven
at less than 15 mph into the middle of next week.
&&
.PREV DISCUSSION...Expect isolated to scattered showers/tstms
Thursday afternoon/evening from Tucson east and south, then a slight
chance of showers/tstms east of Tucson late Thursday night into
Friday evening. Have maintained a slight chance of showers/tstms
Saturday across the White Mountains and far southeastern
sections.
Thereafter, the GFS/ECMWF/CMC were nearly identical with depicting a
closed upper low over Oregon Sunday. A tighter mid-level gradient
will translate into stronger wly flow aloft, and shunt deeper
moisture well east of this forecast area. High pressure aloft is
progged to build over the southwestern CONUS Tue-Wed, and the upper
flow will weaken in response. However, the GFS/ECMWF depicted a very
dry regime across southeast Arizona, and precip-free conditions are
expected area-wide into the middle of next week. Only minor daily
temp changes will prevail into the middle of next week as well.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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Area Forecast Discussion
National Weather Service Tucson AZ
844 PM MST WED JUL 6 2016
.SYNOPSIS...Isolated to scattered afternoon and evening
thunderstorms will prevail mainly east to south of Tucson through
Friday. A few thunderstorms may occur across the White Mountains and
far southeastern sections Saturday, then dry conditions area-wide
Sunday into next Wednesday.
&&
.DISCUSSION...Showers and thunderstorms developed pretty much as
expected this afternoon with the bulk of the activity across Santa
Cruz and Cochise counties with the northwestern edge right in
Tucson. A few of the storms dropped up to about 1.25 inches of rain
in localized spots which created some minor flooding issues. The
latest KEMX radar imagery shows all the remaining thunderstorms are
now over Sonora with areas south and east of Tucson seeing
considerable debris cloudiness and perhaps a few sprinkles or very
light showers. Expect this activity to continue to diminish over the
next few hours. There is a clear distinct remnant circulation from
the MCV we`ve been looking at all day across Central/Northern Sonora.
This is progged to move northeast in the southwest flow aloft into
Cochise County early Thursday morning. Thus, will continue to depict
slight chance PoPs overnight into Thursday morning south and east of
Tucson. Enough moisture remains from Tucson eastward for isolated to
scattered showers and thunderstorms Thursday afternoon. Have already
sent a couple of updates this evening to account for latest trends
overnight. Otherwise, forecast looks in good shape. See previous
forecast discussion below for additional information.
&&
.AVIATION...VALID THRU 08/06Z.
A slight chance of -TSRA/-SHRA is possible for
KDUG/KOLS terminals overnight into Thursday morning. By Thursday
afternoon, expect isolated to scattered -SHRA/-TSRA from Tucson south
and eastward to the New Mexico/international
borders this evening.
Otherwise, clear skies to scattered clouds above 20k ft msl will
prevail west to northwest of KTUS thru Thursday afternoon. Surface
winds will be mainly light into Thursday morning, becoming
wly at 10-15 kts with gusts to 20 kts Thursday afternoon before
tapering off Thursday evening. Aviation discussion not updated for
TAF amendments.
&&
.FIRE WEATHER...Isolated to scattered showers and thunderstorms will
occur from Tucson eastward and southward through Friday. A
few thunderstorms may occur across the White Mountains and far
southeastern sections Saturday, then dry conditions will prevail
area-wide Sunday through next Wednesday. Apart from brief gusty
thunderstorm outflows, 20-foot winds will generally be terrain driven
at less than 15 mph into the middle of next week.
&&
.PREV DISCUSSION...Expect isolated to scattered showers/tstms
Thursday afternoon/evening from Tucson east and south, then a slight
chance of showers/tstms east of Tucson late Thursday night into
Friday evening. Have maintained a slight chance of showers/tstms
Saturday across the White Mountains and far southeastern
sections.
Thereafter, the GFS/ECMWF/CMC were nearly identical with depicting a
closed upper low over Oregon Sunday. A tighter mid-level gradient
will translate into stronger wly flow aloft, and shunt deeper
moisture well east of this forecast area. High pressure aloft is
progged to build over the southwestern CONUS Tue-Wed, and the upper
flow will weaken in response. However, the GFS/ECMWF depicted a very
dry regime across southeast Arizona, and precip-free conditions are
expected area-wide into the middle of next week. Only minor daily
temp changes will prevail into the middle of next week as well.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Phoenix AZ
836 PM MST WED JUL 6 2016
.SYNOPSIS...
A break in thunderstorm activity with near average temperatures will
continue into next week. While there will be a temporary incursion
of moisture into portions of Arizona through Thursday, thunderstorm
chances will be limited to southeast Arizona. Quiet weather may
persist through all of next week before any storms can move north
once again.
&&
.DISCUSSION...
Another quiet early July evening across our forecast area. Nearest
activity was/is in far southeast Arizona where moisture/instability
is a bit higher and in the vicinity of a remnant MCV from last
night`s northern Mexico convection. The 07.00Z KPSR sounding depicted
MLCAPE of around 300 J/kg but also CIN values of near 50 J/kg.
Clearly not enough to get anything going this evening. Tail-end of
latest CAMs indicate more of the same for tomorrow as the weak
moisture plume expands a bit further north but still east of the
Phoenix area.
&&
.PREVIOUS DISCUSSION...
Mostly clear skies covered the region. Just a small sampling of
cumulus could be seen forming over southwest Maricopa County and
western Pinal County. Much more cloudiness was seen further south
across Pima and Cochise counties. Dew points rose this morning in
response to a low-level moisture surge with some values even as high
as 70 along the Colorado River valley. At this time dew points are
mostly in the 50s across Maricopa County, a significant increase from
yesterday. The increase is well represented in the 12Z sounding from
Tucson with PW of 1.14 inches and at Phoenix with 0.78 inch. Model
sounding for PHX indicates this pool of moisture should remain for
another two days, through Friday. This is associated with an inverted
trough in northeastern Sonora state of Mexico. Models indicate a
return to zonal westerlies by this weekend which should put a damper
on this low-level monsoon activity that we`re seeing this week.
Temperatures should remain around normal levels for early July, near
107, for Phoenix. Did a minor adjustment on PoPs this morning to
boost them up for the eastern half of CWA for the next three days to
reflect the low-level monsoon activity that we`re seeing. Otherwise
the rest of the forecast period looks uneventful, with a return to
dry conditions this weekend through middle part of next week.
The most notable weather feature locally through the weekend and
into early next week is actually the complete lack of weather and
thunderstorm activity. Deep negative height anomalies (around 2
normalized standard deviations below average) will propagate from the
Pacific NW into the Great Basin with intense jet energy punching over
the Sierra chain towards the central Rockies. Essentially every NAEFS
member shows this scenario where the mid and upper tropospheric
u-wind component becomes anomalously strong and within a
climatologically rare threshold for mid July. Unlike much of the
summer season, forecast confidence is exceedingly high and so much so
as to assign absolutely no chance of rainfall for the entire Sat- Wed
time frame as aggressive drying spreads through the atmospheric
column. Furthermore with this increased westerly flow and depressed
troughing pattern, H5 heights will languish only around 590dm
yielding temperatures very close to the seasonal climatology.
&&
.AVIATION...
South-Central Arizona Including KPHX, KIWA, and KSDL:
Quiet night expected as breezy westerly winds gradually diminish and
turn weakly to the southeast for the morning push. No thunderstorm
activity expected tonight
Southeast California/Southwest Arizona including KIPL and KBLH:
Southerly component to the surface winds to prevail through Thursday
with afternoon gusts 20-25 kts (most noticeably over Lower Colorado
River Valley). An exception will be near and west of the Imperial
Valley where westerly winds will develop this evening (gusting 25-30
kts west of NJK).
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Saturday through Wednesday...
Dry southwesterly flow will be place over the weekend and the first
half of next week. This will mean low minimum humidities (at or below
10% for the lower deserts and at or below 20% for higher terrain)
with only fair overnight recovery. This will also mean rather breezy
conditions at times - most noticeably Sunday and Monday. At this time
however, critical fire weather thresholds are not anticipated.
Temperatures will be normal.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Iniguez/Waters/MO
AVIATION...Iniguez/AJ
FIRE WEATHER...AJ
Area Forecast Discussion
National Weather Service Phoenix AZ
836 PM MST WED JUL 6 2016
.SYNOPSIS...
A break in thunderstorm activity with near average temperatures will
continue into next week. While there will be a temporary incursion
of moisture into portions of Arizona through Thursday, thunderstorm
chances will be limited to southeast Arizona. Quiet weather may
persist through all of next week before any storms can move north
once again.
&&
.DISCUSSION...
Another quiet early July evening across our forecast area. Nearest
activity was/is in far southeast Arizona where moisture/instability
is a bit higher and in the vicinity of a remnant MCV from last
night`s northern Mexico convection. The 07.00Z KPSR sounding depicted
MLCAPE of around 300 J/kg but also CIN values of near 50 J/kg.
Clearly not enough to get anything going this evening. Tail-end of
latest CAMs indicate more of the same for tomorrow as the weak
moisture plume expands a bit further north but still east of the
Phoenix area.
&&
.PREVIOUS DISCUSSION...
Mostly clear skies covered the region. Just a small sampling of
cumulus could be seen forming over southwest Maricopa County and
western Pinal County. Much more cloudiness was seen further south
across Pima and Cochise counties. Dew points rose this morning in
response to a low-level moisture surge with some values even as high
as 70 along the Colorado River valley. At this time dew points are
mostly in the 50s across Maricopa County, a significant increase from
yesterday. The increase is well represented in the 12Z sounding from
Tucson with PW of 1.14 inches and at Phoenix with 0.78 inch. Model
sounding for PHX indicates this pool of moisture should remain for
another two days, through Friday. This is associated with an inverted
trough in northeastern Sonora state of Mexico. Models indicate a
return to zonal westerlies by this weekend which should put a damper
on this low-level monsoon activity that we`re seeing this week.
Temperatures should remain around normal levels for early July, near
107, for Phoenix. Did a minor adjustment on PoPs this morning to
boost them up for the eastern half of CWA for the next three days to
reflect the low-level monsoon activity that we`re seeing. Otherwise
the rest of the forecast period looks uneventful, with a return to
dry conditions this weekend through middle part of next week.
The most notable weather feature locally through the weekend and
into early next week is actually the complete lack of weather and
thunderstorm activity. Deep negative height anomalies (around 2
normalized standard deviations below average) will propagate from the
Pacific NW into the Great Basin with intense jet energy punching over
the Sierra chain towards the central Rockies. Essentially every NAEFS
member shows this scenario where the mid and upper tropospheric
u-wind component becomes anomalously strong and within a
climatologically rare threshold for mid July. Unlike much of the
summer season, forecast confidence is exceedingly high and so much so
as to assign absolutely no chance of rainfall for the entire Sat- Wed
time frame as aggressive drying spreads through the atmospheric
column. Furthermore with this increased westerly flow and depressed
troughing pattern, H5 heights will languish only around 590dm
yielding temperatures very close to the seasonal climatology.
&&
.AVIATION...
South-Central Arizona Including KPHX, KIWA, and KSDL:
Quiet night expected as breezy westerly winds gradually diminish and
turn weakly to the southeast for the morning push. No thunderstorm
activity expected tonight
Southeast California/Southwest Arizona including KIPL and KBLH:
Southerly component to the surface winds to prevail through Thursday
with afternoon gusts 20-25 kts (most noticeably over Lower Colorado
River Valley). An exception will be near and west of the Imperial
Valley where westerly winds will develop this evening (gusting 25-30
kts west of NJK).
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Saturday through Wednesday...
Dry southwesterly flow will be place over the weekend and the first
half of next week. This will mean low minimum humidities (at or below
10% for the lower deserts and at or below 20% for higher terrain)
with only fair overnight recovery. This will also mean rather breezy
conditions at times - most noticeably Sunday and Monday. At this time
however, critical fire weather thresholds are not anticipated.
Temperatures will be normal.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
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DISCUSSION...Iniguez/Waters/MO
AVIATION...Iniguez/AJ
FIRE WEATHER...AJ
Area Forecast Discussion
National Weather Service Tucson AZ
350 PM MST WED JUL 6 2016
.SYNOPSIS...Isolated to scattered afternoon and evening
thunderstorms will prevail mainly east to south of Tucson through
Friday. A few thunderstorms may occur across the White Mountains and
far southeastern sections Saturday, then dry conditions area-wide
Sunday into next Wednesday.
&&
.DISCUSSION...Scattered showers and thunderstorms were occurring from
the far southern portion of the Tucson metro area eastward and
southward to the New Mexico/international borders at this time.
Rainfall amounts have generally been around one quarter of an inch,
though a few amounts to around one half of an inch have occurred.
Brief wind gusts to near 30 mph have also been observed.
Have noted that several HRRR solutions since 18Z have gradually
trended downward in coverage and intensity of showers/tstms for the
rest of this afternoon and evening versus HRRR solutions prior to
18Z. Storm Prediction Center Mesoscale Analysis suggests some
stabilization has occurred during the past 1-2 hours, with MUCAPES
of around 1000 J/kg versus values approaching 1500 J/kg near the
international border earlier this afternoon.
For this forecast issuance, have continued with scattered showers/
tstms from Tucson southward this evening, then a slight chance of
showers/tstms mainly from Tucson east and south late tonight. Am
somewhat concerned about any showers/tstms to occur late tonight,
since the GFS was the only model to depict measurable precip to
potentially occur. Expect isolated to scattered showers/tstms
Thursday afternoon/evening from Tucson east and south, then a slight
chance of showers/tstms east of Tucson late Thursday night into
Friday evening. Have maintained a slight chance of showers/tstms
Saturday across the White Mountains and far southeastern
sections.
Thereafter, the GFS/ECMWF/CMC were nearly identical with depicting a
closed upper low over Oregon Sunday. A tighter mid-level gradient
will translate into stronger wly flow aloft, and shunt deeper
moisture well east of this forecast area. High pressure aloft is
progged to build over the southwestern CONUS Tue-Wed, and the upper
flow will weaken in response. However, the GFS/ECMWF depicted a very
dry regime across southeast Arizona, and precip-free conditions are
expected area-wide into the middle of next week. Only minor daily
temp changes will prevail into the middle of next week as well.
&&
.AVIATION...VALID THRU 08/00Z.
Scattered -TSRA/-SHRA will occur from KTUS vicinity east and south
to the New Mexico/international borders this evening and again
Thursday afternoon. A slight chance of -TSRA/-SHRA exists late
tonight into Thursday morning, mainly east to south of KTUS.
Otherwise, clear skies to scattered clouds above 20k ft msl will
prevail west to northwest of KTUS thru Thursday afternoon. Surface
wind this evening and Thursday afternoon will generally be wly at 10-
15 kts with gusts to 20 kts. Otherwise, surface wind will be variable
in direction at less than 10 kts. Aviation discussion not updated for
TAF amendments.
&&
.FIRE WEATHER...Isolated to scattered showers and thunderstorms will
occur from Tucson eastward and southward Wednesday through Friday. A
few thunderstorms may occur across the White Mountains and far
southeastern sections Saturday, then dry conditions will prevail
area-wide Sunday through next Wednesday. Apart from brief gusty
thunderstorm outflows, 20-foot winds will generally be terrain driven
at less than 15 mph into the middle of next week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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AREA FORECAST DISCUSSION
National Weather Service Northern Indiana
726 PM EDT WED JUL 6 2016
.SYNOPSIS...
Issued at 206 PM EDT Wed Jul 6 2016
Just a slight chance of showers and thunderstorms will persist
overnight into Thursday morning. Thereafter...the chances for
showers and storms increase substantially by late Thursday
afternoon into Friday. Strong to severe storms are possible from
Thursday afternoon into Thursday night. Hot and humid conditions
can be expected through Friday, with afternoon heat indices into
the mid 90s each afternoon. Cooler and less humid conditions will
then push into the area for the weekend behind a cold front. High
temperatures today will reach into the mid to upper 80s, with low
temperatures tonight only dropping into the lower 70s.
&&
.SHORT TERM...(This Evening through Thursday)
Issued at 302 PM EDT Wed Jul 6 2016
Convoluted pattern through Friday with mesoscale
boundaries...convectively enhanced short waves and synoptic features
all combining for an active and difficult forecast.
Early morning MCS worked over atmosphere and provided a cloud canopy
to help stabilize lower levels. Finally starting to see recovery with
clearing but low level CIN remains in place and doubt it will be
able to overcome on a large scale this evening. Hires guidance seems
to agree with little additional development shown this evening or
overnight. Will have to watch MCV moving east out of northeast MO. A
few of the various WRF runs want to develop some convection on the
northern periphery of this feature where differential heating may
have led to a modest instability gradient and weakened CIN. Given
the low chance for this development opted to keep just slight chance
pops in forecast for the evening. Rest of overnight appears to
remain quiet given most hires models but there are some theta E
maxes progged to rotate through and any subtle short wave may allow
for an isolated storm overnight coincident with these moisture
boundaries. A weak boundary will also slip into the north which may
help develop an isolated storm. Kept a slight chance through the
night to also blend with neighboring offices. May also see some fog
development late near this boundary with light winds and high low
level moisture content. Not confident enough that it will be dense
enough for grid mention but worth noting given development that
occurred Tuesday morning.
Thursday still looks very interesting with severe potential in late
afternoon and especially the evening and overnight. Deep layer shear
still looks strong with 30-40 knots on average by afternoon.
Potential instability could be very high depending on cloud cover
but capped atmosphere with warm layer aloft and short wave ridge
should yield at least partly cloudy skies. NAM and GFS both pointing
toward MUCAPES of 4-5 j/kg or greater coincident with the increased
shear. PWATS on order of 2 inches also expected so fuel will be in
place.
Trigger mechanism will be in the form of a short wave moving east in
the zonal flow aloft. Timing in latest 12z guidance suggest an MCS
upstream will be ongoing with this feature and could approach our
west by late afternoon or early evening. Potential does remain for
widespread severe weather in the form of a QLCS with wind and
locally heavy rain the primary hazards. A few models have at times
shown a decent surface wave moving through the northern CWA.
This would back the low level winds and given the amount of shear in
place could lead to rotating storms and a hail and isolated tornado
threat as well. Latest runs are not as aggressive with this scenario
but it will need to be watched. There is also some potential that
first MCS could dive southeast while a second system develops
upstream tomorrow evening and comes east. A few models even split
the CWA. Given the uncertainty in timing and evolution have opted to
stay in the high chance range with pops for now as we have been
burned as recently as this past week with MCS/s.
&&
.LONG TERM...(Thursday Night through Wednesday)
Issued at 302 PM EDT Wed Jul 6 2016
Main cold front still set to move through the local area Friday. The
big question is how much instability will be left in place when
frontal passage occurs. Atmosphere will likely be worked over and
possibly scoured from Thursday night storm complex. A lot of
uncertainty exists for Friday based on this storm evolution. At this
time will continue to carry mid chance pops on Friday with best
chances in the east where timing will be most favorable in afternoon
with greater instability potential.
Cooler and drier air will work in for the weekend. Northwest flow
aloft expected and models hinting at a few embedded weak short waves
diving out of Michigan. No plans to introduce any PoP greater than
14 percent given dry low levels but will have to watch these waves
and any strengthening in successive model runs.
GFS and ECMWF bring a rather stout looking mid level ridge into the
area early next week with increasing warmth once again. TSRA chances
return sometime Tuesday into Wednesday as a short wave is progged to
ride southwest flow aloft while ridge slides east of the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 723 PM EDT Wed Jul 6 2016
General vfr conds xpcd through the pd. Although can not rule out
some potential mvfr vsby restriction ltr tonight as high cld
shield thins in face of contg ll thermal inversion and wk bndry
lyr mstr advtn esp late.
&&
.IWX Watches/Warnings/Advisories...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Murphy
SHORT TERM...Lashley
LONG TERM...Lashley
AVIATION...T
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Area Forecast Discussion
National Weather Service Indianapolis IN
726 PM EDT WED JUL 6 2016
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 433 PM EDT Wed Jul 6 2016
Indiana will stay between high pressure over to the south and east
and a front over the Great Lakes into Thursday. Friday the front is
forecast to turn into a cold front and move east of our state.
High pressure following the front later in the weekend will control
Indiana weather for much of next week as it sets up from the Gulf
coast to the eastern Lakes.
&&
.NEAR TERM (Tonight and Thursday)...
Issued at 242 PM EDT Wed Jul 6 2016
The main issue is precipitation chances.
Latest observations show the atmosphere has stabilized over central
Indiana. The HRRR says convection won`t refire through evening. All
models have positive equivalent potential temperature advection over
the southwest by late night, suggesting nocturnal convection.
The blend has only chance POPs tonight, but the shorter term and
smaller scale signals allow adding some precision. The forecast is
for likely in southwest to slight chance northeast tonight.
For Thursday once morning convection dies, we should have a lull. In
the afternoon there is a chance of redevelopment depending what
happens with destabilization versus cap development.
For temperatures, forecast certainty is low. Much will depend on
location and timing of convection. Considering the background
model forecasts, a blend should keep errors within 3 degrees or so
and will be used.
&&
.SHORT TERM (Thursday night through Saturday)...
Issued at 242 PM EDT Wed Jul 6 2016
The main issue is precipitation chances.
The models more or less agree with a drying trend as a cap builds early
in the period and drier air arrives during the weekend.
There a lot of differences in specifics. One example is POPs of 60
and 13 at IND tomorrow night from the MAV and MET respectively.
This disagreement is normal forecasting convection more than 36
hours in advance. Using a blend will reduce the chance for large
errors. POPs may be changed by at least 20 percent and
temperatures by at least 3 degrees based on later information.
&&
.LONG TERM /Saturday Night through Wednesday/...
Issued at 149 PM EDT Wed Jul 6 2016
ECMWF continues to suggest High pressure at the surface along with
ridging aloft in place across Indiana through this period.
Northerly winds on the front of the high on Saturday Night and
Sunday look to eventually give way to warmer...southerly flow by
Mon-Wed as Indiana arrives on the back side of the Ridge and High
pressure system. Little seen in the way of forcing. Superblend
continues to suggest pops as warmer and more southerly flow
arrives early next week. Confidence in this is low at this time
given the lack of a forcing mechanism other than a return of
moisture and daytime heating. Have tried to trend toward only
slight chance pops during that time...not far from superblend.
&&
.AVIATION /Discussion for 070000Z TAF issuance/...
Issued at 716 PM EDT Wed Jul 6 2016
Mainly VFR conditions expected through 6z at the sites. At KLAF
could see some of the scattered convection currently over
northeast IL/northwest Indiana make its way near so included a
VCTS there 1-5z based on current obs and hi res output. This
output also indicated KHUF could see some activity around 4z. Given
the cap over the sites though expect any convection to weaken and
have a difficult time maintaining itself, so at KHUF only included
a VCSH and left KIND and KBMG without any convective mention.
Given the amount of soil moisture and forecast dewpoint depression
at the surface and in the boundary layer of only a degree or two,
could see some low stratus or vsbys develop. With some mixing as
the MCV moves through to the south may favor stratus rather than
fog. SREF probabilities for significant restrictions are low
though and MOS guidance is pretty optimistic. Therefore will
continue with mention of scattered 600 ft deck and add in MVFR
visibilities, with a tempo of IFR at KLAF and KBMG. Will generally
run these conditions starting around 6-9z and ending around 13z.
Convection will be a threat again tomorrow, but right now
uncertainty on timing/placement is too high to include any
mention. Winds should remain light and drop to near calm overnight
before returning to 5-10 kts out of the southwest tomorrow.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....PUMA
AVIATION...CP
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
637 PM CDT WED JUL 6 2016
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Thursday)
Issued at 328 PM CDT WED JUL 6 2016
Effects of northeast and southern KS convection this morning has
left airmass over the forecast area drier and not as hot as
previously forecast. Thus, have struggled to have HI values
approach 100 degrees across most of the area and have cancelled Heat
Advisory.
Main questions for the forecast for tonight and Thursday are: What
will be the mechanism for potential thunderstorms affecting us
tonight and Thursday, and whether temps and dewpoints will reach
high enough to meet heat index criteria Thursday afternoon?
For the latter question, currently forecasting temps in the mid 90s
in the north and east with upper 90s possible over portions of
central KS. Dewpoints are forecast to range from the lower to
possibly middle 70s in the east, while upper 60s to near 70 is more
realistic over central KS. This would lead to max HI values from 100
to 105 nearing advisory criteria. However, there is enough
uncertainty in reaching these values if we have our airmass once
again modified by convective outflows and some cloudiness from
overnight/morning thunderstorms near our area. Thus, have not
issued an advisory for Thursday and will let midnight forecast crew
decide on that as potential convective effects become less uncertain.
Water vapor loop shows a weak shortwave trough over extreme western
KS, and possibly another one to the northwest in northern CO.
Most short and medium range models do not develop persistent
convection with these features. However a few runs of the HRRR and
experimental HRRR have been developing a cluster of storms over
eastern CO or southwest KS and bringing the associated convection
across eastern KS after midnight. Given inconsistency of these
HRRR runs, have not included any significant POPs from this
forecast convection. Possibly more likely scenario would be closer
to going forecast, and perhaps best depicted by 12Z NAM, where an
MCS is forecast to affect primarily Nebraska, with tail end
affecting far northern and northeastern KS late tonight and
Thursday morning. This is what has been put in forecast grids, but
developments over western KS will obviously have to be monitored
for HRRR scenarios.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 328 PM CDT WED JUL 6 2016
Strong upper wave will move across the Upper Midwest pushing a cold
front across the area Thu night. Capping and stronger lift
associated with the wave should keep the bulk of the precip NE of
the area but will keep low chcs in the northeast given strength of
wave. The front will sag into southern KS on Friday and will keep
low chcs across the southern counties near the front. By Friday
night into the weekend confidence in location and timing of precip
is low since recent performance of models has been poor with
placement of nocturnal convection. That said chcs would appear to
increase at least across central KS Fri night as the thetaE
advection increases atop the boundary. The area will remain within
the weak upper ridge with overnight storm chcs through the weekend
before a unusually strong upper trough moves into the Rockies by
early next week. This trough will push a front into the region by
later Monday into Tues so it would appear best chcs for organized
storms would occur around that time frame. The front will hang up
across the area toward mid week and with zonal flow wouldn`t be
surprised to see storm chcs persist through next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 637 PM CDT WED JUL 6 2016
VFR conditions should dominate. Thunderstorm chances remain the
only concern but still too low for any inclusion.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...GDP
LONG TERM...Omitt
AVIATION...65
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
333 PM CDT TUE JUL 5 2016
.SHORT TERM...(This Evening through Wednesday)
Issued at 332 PM CDT TUE JUL 5 2016
Late this afternoon temperatures were in the late 90s with dewpoints
int he the mid to upper 70s across east central KS, which has caused
heat indices to be in the 110 to 114 degree range. The mixing was a
bit deeper across the western counties where dewpoints have dropped
into the upper 60s to lower 70s.
Most numerical models do not show thunderstorms developing across
the CWA this afternoon and evening, though MLCAPE values range from
4,000 to 5,000 J/KG. The HRRR is the only model that shows isolated
thunderstorms developing across the CWA late this afternoon and
evening but based on the lack of vertical CU development, I really
do not see any boundary or minor vortmaxes that could help increase
ascent for any thunderstorm development late this afternoon.
Tonight, most models show scattered thunderstorms across northeast
CO and the southern NE Panhandle this afternoon congealing into an
MCS which will track east or southeast across the plains. The HRRR,
NAM, and WRF solutions show the MCS tracking southeast across the
CWA, though it may begin to weaken as it moves into northeast and
east central KS late Tonight. If an MCS develops and maintains its
intensity through the night then there will be a chance for heavy
rainfall and potential damaging wind gusts along with penny to
quarter size hail, with the better chance for strong to severe
thunderstorms across north central KS during the early morning
hours Wednesday. The exact track and the intensity of the MCS will
not be known until it develops and begins to propagate to the
southeast. Therefore, I went with chance pops after 6Z across the
CWA but there will be higher pops wherever the MCS tracks.
Wednesday, The morning thunderstorm complex will exit the eastern
counties of the CWA by 15Z. Skies should clear from west to east
across the CWA during the late morning and early afternoon hours.
Highs should warm into the lower and mid 90s across the southern
counties along with dewpoints holding in the mid 70s. If the MCS
remains intense through the morning hours, then an outflow boundary
may shift south of the CWA and the cloud cover may hold through most
of the afternoon hours keeping Highs several degrees cooler. At this
time I think we will clear out by afternoon and heat up into the mid
90s south of I-70. Therefore I have issued a heat advisory for areas
along and south of I-70 from 12 Noon through 8 PM Wednesday where
heat indices around 105 degrees during the afternoon hours.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 332 PM CDT TUE JUL 5 2016
Wednesday Night through Friday...
Storms are expected to form in NW Kansas and SW Nebraska Wednesday
evening and move east toward the area overnight. There is a chance
some storms may make it into the northern portion of the CWA by late
evening so low end PoPs are included during this time frame mainly
north of I-70. Thunderstorm chances continue for Thursday as another
shortwave is forecast to move through late afternoon into the
evening. Soundings indicate a cap will be in place most of the
afternoon Thursday, but with a front in the area and sufficient
heating, the cap should degrade allowing a chance for storms to
form. Models show high CAPE values over 3000 J/kg along with 0-6 km
shear ranging between 25-35 knots. This makes organized convection
possible with strong winds and gusty hail being the main hazard.
Friday looks to have the best chance to be dry, although another
shortwave near central Kansas may provide some focus for storms in
east central Kansas during the afternoon Friday. As for
temperatures during this time, the hottest day looks to be Thursday
with heat indicies once again near 105 degrees due to dewpoints in
the low 70s Thursday afternoon. The front finally makes it through
the area this day allowing Friday to cool slightly with highs in the
low 90s.
Friday Night through Tuesday...
Weak mid-level ridging will be in place at the beginning of the
period. A frontal boundary is expected to stall in southern Kansas
Saturday afternoon. This may be the focal point for thunderstorm
development Saturday afternoon and evening. An amplified trough will
be in place across the Western US late next weekend. EC and GFS
differ on the effects from the trough. GFS much more bullish with
strength of a shortwave trough lifting out from base of the trough.
The unsettled pattern will continue through the remainder of the
period as a potentially unstable atmosphere will be in place. As mid-
level southwesterly flow settles in across the area, weak embedded
waves will have the potential to spark thunderstorm activity for the
remainder of the period. Temperatures will remain fairly seasonal
with high temperatures in the upper 80s to lower 90s. With dew
points near 70 degrees, heat index values will range from the mid-
90s to near 100 degrees for the entire extended period.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1240 PM CDT TUE JUL 5 2016.
Expect VFR conditions through most of the next 24 hours.
Scattered thunderstorms may move across the terminals between 6Z
and 15Z WED, which could potentially provide brief MVFR
visibilities and cloud cover.
&&
.TOP Watches/Warnings/Advisories...
Heat Advisory until 8 PM CDT this evening for KSZ008>012-020>024-
026-034>040-054>056-058-059.
Heat Advisory from 1 PM to 8 PM CDT Wednesday for KSZ034>039-
054>056-058-059.
&&
$$
SHORT TERM...Gargan
LONG TERM...Heller/Baerg
AVIATION...Gargan
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
621 AM CDT TUE JUL 5 2016
...AVIATION UPDATE...
.SHORT TERM...(Today and Tonight)
Issued at 338 AM CDT TUE JUL 5 2016
08Z water vapor imagery shows the mean westerlies remain to the
north with a closed upper low over British Columbia and a wave
moving through MT. There also appears to be an upper wave moving
into southwest KS that is helping fire convection over the TX
panhandle. At the surface, moist air with dewpoints in the 70s
stretched north through much of central and eastern KS with some obs
sites in central KS show a dewpoint temp near 75. A general trough
of low pressure extended from the southern high plains north through
central NEB and delineated the moist air to the east from the
dryer air over the high plains.
For today and tonight, the general consensus is that the warm air
advecting over the forecast area now is likely to keep the boundary
layer capped until maybe late in the day during peak heating. Then
storms that form out west should congeal into a convective system
and track east. The upper wave over southwest KS poses a wrench in
that it may provide enough forcing along the surface trough for
convection to develop earlier in the day and more across central KS.
This may bring a potential for storms into north central KS a little
sooner in the day rather than waiting for storms to form an MCS
further northwest and move into the area. Unfortunately there is not
a lot of confidence in thunderstorm coverage. The NAM, which has
been consistent in diving an MCS across the forecast area tonight
has little support from the ARW and NMM which tend to keep
convection more isolated through the night. Because there is not a
strong surface feature or convergence to focus convective initiation
over KS and upper flow is relatively week resulting in 0-6km shear
of about 20KT, it is unclear where storms may track this afternoon
and tonight. The forecast stays a little more with the model
consensus of storms to move in from NEB this evening and overnight,
and the higher POPs are across northern KS where there is some
consistent signal for an MCS. There should be no problem from an
instability perspective for strong or severe storms to develop. But
the weak shear is expected to favor a MCS. This would suggest a
damaging wind and hail risk with the storms.
Will expand the heat advisory to include all of the counties in the
forecast area. There seems to be a balancing act this afternoon
regarding temps with how deep the boundary layer mixes and how low
the dewpoints may drop. I suspect eastern KS is as close to a slam
dunk for the heat advisory as there can be with temps in the mid 90s
and dewpoints holding in the lower and middle 70s. If north central
KS mixes as deep as some of the forecast soundings show, highs are
likely to hit triple digits. However models show surface and 850
winds backing during the afternoon to a more southerly direction
suggesting the forecast soundings may be over doing the mixing and
lower dewpoints. In any case, think heat indicates will be close to
105 for Ottawa, Cloud and Republic counties and will put them in the
advisory. As for temps, have a similar forecast to the previous with
mid 90s in eastern KS to near 100 for the Abilene area. Lows tonight
will be completely dependent on where any MCS tracks. Because of
this I`ve stayed close to the model blend which is kind of a middle
of the road forecast. If there are no thunderstorms, lows are
probably going to be more mild across north central KS. If the MCS
moves through the center of the forecast area, lows could be
several degrees cooler than the forecast has.
.LONG TERM...(Wednesday through Monday)
Issued at 338 AM CDT TUE JUL 5 2016
For the mid range forecast beginning Wednesday day time frame, it is
still unclear exactly how much influence overnight convection may
have on overall temps and dewpoints. Therefore, have not gone with
issuing a heat advisory for Wednesday at this time and will have to
hold off on that just a bit longer. Expecting that right now we
still warm up with heat indices just below or perhaps just reaching
into criteria but confidence isn`t high enough at this time to
determine where if any outflow boundaries exist and complicate the
daytime mixing. It is possible that some localized higher temps
will be reached over the area and dewpoints are still high enough
to have a few readings into the lower 100s heat index wise.
Wednesday night into Thursday morning, do expect that a nocturnal MCS
will form and over the western portions of the Northern Plains as
lead shortwaves lift out ahead of a deeper Pacific trough
advecting into the Northern Rockies. Trends with synoptic models
tend to be suggesting that perhaps the best 850mb theta-e moisture
may reside off into the northern portions of the forecast area
into Nebraska. This along with better deep layer shear would help
maintain any MCS incoming into the region and therefore have kept
slight chance POPs mainly north and along I-70. Into the day and
afternoon on Thursday, as the upper trough advects across the
Northern Plains into the Upper MS Valley, a weak cold front should
be pushed into the forecast area. Some sounding profiles suggest
that a strong cap will remain in place, but if convergence is
strong enough to degrade the cap, likely along with heating, then
there could be storms form mainly in the afternoon and some could
be severe as effective shear increases to the order of 35-40kts.
Most likely threats would be hail around 1 inch and some strong
gusty winds. Low confidence in how this will actually play out at
this point. Temps again on Thursday could reach into the advisory
range prior to any storm development.
Into the weekend, the previously mentioned cold front stalls out
over central and southern KS and becomes the focus for periods of
showers and thunderstorm chances for the weekend and into the
upcoming week as weak isentropic ascent on the 310K to 315K surface
sets up into the region on the weekend. Mean Westerly flow aloft
remains over the northern tier CONUS, so expecting generally
weaker shear profiles for any storms that do occur. Generally
expect heights to rise again with temps to begin climbing back to
near advisory range by early next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 621 AM CDT TUE JUL 5 2016
VFR conditions are likely to prevail into the evening. The main
question is whether a capping inversion will prevent diurnal
convection during the heat of the day. The HRRR has been showing
the possibility for ISOLD storms. Most other guidance including
the RAP and NAM fail to develop storms near the terminals during
the afternoon. Therefore have no mention of TS until the overnight
hours when an MCS could move across the region. At this point,
confidence in where storms will track is low, so have only
included a PROB30 to reflect the chances in the forecast.
&&
.TOP Watches/Warnings/Advisories...
Heat Advisory from noon today to 8 PM CDT this evening for
KSZ008>012-020>024-026-034>040-054>056-058-059.
&&
$$
SHORT TERM...Wolters
LONG TERM...Drake
AVIATION...Wolters
Area Forecast Discussion
National Weather Service Little Rock AR
358 AM CDT THU JUL 7 2016
.SHORT TERM...Today Through Friday Night
Similar setup to yesterday across the region with surface high
pressure in place to the southeast and low pressure noted across the
Southern Plains. Two MCS`s noted across the region with the first
impacting Tennessee/Kentucky and the second moving out of SE
Nebraska into northeastern Kansas.
Should see fewer impacts to the forecast area from upstream MCS in
Kansas due to more northerly location and easterly trajectory. Early
morning HRRR runs attempt to initiate some shower and thunderstorm
activity across E Oklahoma with a weak shortwave in the mean flow
and shift this activity toward Arkansas throughout the day. No
activity has manifested itself as of 09z so will keep forecast
dry attm though wouldn`t be surprised to see at least a few
isolated showers develop.
SW flow at the surface will be in place again today and winds will
be enhanced due to increased pressure gradient. Wind speeds will
likely be aoa 12-18mph with gusts as high as 25mph at times. The
other notable mention of the day goes to heat index values across
the state. With dewpoints in the 70s and temps cranking into the
mid to upper 90s, another run at heat index values of 105 will be
made this afternoon.
Rain chances will be in place across mainly northern Arkansas on
Friday as a surface boundary approaches from the NW. Additionally,
the H500 pattern begins to show signs of transitioning to more of an
active period with more of a NW flow expected. Will have to keep an
eye on temps/heat indices Friday as heat indices could approach
heat advisory levels once again across the southern half of the
state. Could see chances for a more notable thunderstorm complex
approaching the state from the northwest late Friday night.
&&
.LONG TERM...Saturday Through Wednesday
As a ridge of high pressure weakens over the southeast United
States, a cold front will be allowed to drop through the Ohio and
Tennessee Valleys during the upcoming weekend. The front may
actually make it into northeast Arkansas. Isolated to scattered
showers and thunderstorms are in the forecast. Given more clouds,
it will be slightly cooler.
A few storms may be severe as the front nears the region. Damaging
winds and hail will be the main concerns. An organized severe
weather event is not expected at this point. Heavy downpours in the
northeast half of the state may result in localized flash flooding.
Heading into early next week, a big trough of low pressure will be
noted out west. This will cause ridging farther east, and the front
will be forced to move away from Arkansas to the north. The
heat will return, and precipitation chances will decrease.
Temperatures will be near to a little above average for much of the
period. Readings may be a touch below average toward the
Missouri border this weekend near the aforementioned front.
&&
.PRELIMINARY POINT TEMPS/POPS...
Batesville AR 95 78 93 75 / 10 10 30 30
Camden AR 97 77 96 78 / 0 0 10 20
Harrison AR 93 76 90 72 / 10 10 30 40
Hot Springs AR 96 79 95 77 / 0 0 20 30
Little Rock AR 97 78 96 78 / 0 0 20 30
Monticello AR 97 78 96 79 / 0 0 10 20
Mount Ida AR 95 78 93 75 / 0 0 20 30
Mountain Home AR 95 76 91 73 / 10 10 30 40
Newport AR 95 78 95 76 / 10 10 20 30
Pine Bluff AR 97 77 95 78 / 0 0 10 20
Russellville AR 98 77 94 76 / 10 0 20 30
Searcy AR 96 77 95 76 / 10 0 20 30
Stuttgart AR 96 77 95 78 / 0 0 10 20
&&
.LZK Watches/Warnings/Advisories...
Heat Advisory from 10 AM this morning to 8 PM CDT this evening
FOR Arkansas-Bradley-Calhoun-Clark-Cleburne-Cleveland-Conway-
Dallas-Desha-Drew-Faulkner-Garland-Grant-Hot Spring-Independence-
Jackson-Jefferson-Johnson-Lincoln-Logan-Lonoke-Monroe-Montgomery-
Ouachita-Perry-Pike-Polk-Pope-Prairie-Pulaski-Saline-Scott-Van
Buren-White-Woodruff-Yell.
&&
$$
Short Term...226 / Long Term...46
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1150 PM CDT WED JUL 6 2016
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Thursday)
Issued at 328 PM CDT WED JUL 6 2016
Effects of northeast and southern KS convection this morning has
left airmass over the forecast area drier and not as hot as
previously forecast. Thus, have struggled to have HI values
approach 100 degrees across most of the area and have cancelled Heat
Advisory.
Main questions for the forecast for tonight and Thursday are: What
will be the mechanism for potential thunderstorms affecting us
tonight and Thursday, and whether temps and dewpoints will reach
high enough to meet heat index criteria Thursday afternoon?
For the latter question, currently forecasting temps in the mid 90s
in the north and east with upper 90s possible over portions of
central KS. Dewpoints are forecast to range from the lower to
possibly middle 70s in the east, while upper 60s to near 70 is more
realistic over central KS. This would lead to max HI values from 100
to 105 nearing advisory criteria. However, there is enough
uncertainty in reaching these values if we have our airmass once
again modified by convective outflows and some cloudiness from
overnight/morning thunderstorms near our area. Thus, have not
issued an advisory for Thursday and will let midnight forecast crew
decide on that as potential convective effects become less uncertain.
Water vapor loop shows a weak shortwave trough over extreme western
KS, and possibly another one to the northwest in northern CO.
Most short and medium range models do not develop persistent
convection with these features. However a few runs of the HRRR and
experimental HRRR have been developing a cluster of storms over
eastern CO or southwest KS and bringing the associated convection
across eastern KS after midnight. Given inconsistency of these
HRRR runs, have not included any significant POPs from this
forecast convection. Possibly more likely scenario would be closer
to going forecast, and perhaps best depicted by 12Z NAM, where an
MCS is forecast to affect primarily Nebraska, with tail end
affecting far northern and northeastern KS late tonight and
Thursday morning. This is what has been put in forecast grids, but
developments over western KS will obviously have to be monitored
for HRRR scenarios.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 328 PM CDT WED JUL 6 2016
Strong upper wave will move across the Upper Midwest pushing a cold
front across the area Thu night. Capping and stronger lift
associated with the wave should keep the bulk of the precip NE of
the area but will keep low chcs in the northeast given strength of
wave. The front will sag into southern KS on Friday and will keep
low chcs across the southern counties near the front. By Friday
night into the weekend confidence in location and timing of precip
is low since recent performance of models has been poor with
placement of nocturnal convection. That said chcs would appear to
increase at least across central KS Fri night as the thetaE
advection increases atop the boundary. The area will remain within
the weak upper ridge with overnight storm chcs through the weekend
before a unusually strong upper trough moves into the Rockies by
early next week. This trough will push a front into the region by
later Monday into Tues so it would appear best chcs for organized
storms would occur around that time frame. The front will hang up
across the area toward mid week and with zonal flow wouldn`t be
surprised to see storm chcs persist through next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1150 PM CDT WED JUL 6 2016
Confidence on convection remains low...too low for inclusion.
Thunderstorms to the northwest showing little propagation south
but some potential for this as well as isentropic upglide
development ahead of it remains.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...GDP
LONG TERM...Omitt
AVIATION...65
Area Forecast Discussion...Updated
National Weather Service Little Rock AR
1000 AM CDT THU JUL 7 2016
.Discussion...
Earlier update to add scattered convection over northern AR. Complex
over MO has helped develop this convection associated with short
wave energy moving through the northwest upper flow. Breezy south to
southwest winds of 10 to 20 with gusts to 25 mph across AR. Will
monitor for possible lake wind advisory. Otherwise, temperatures
will warm to the 90s today, and with the added humidity, heat index
values will reach around 105 degrees. A heat advisory is in effect
for most of AR except the northern areas. Late morning update will
fine tune convection chances, possibly adding a bit more southern
areas in slight chance area. (59)
&&
.Prev Discussion.../ Issued 615 AM CDT THU JUL 7 2016/
.AVIATION...
Period of MVFR conditions expected across central and southern AR
terminals this morning as 1500ft ceilings drift in from the
southwest. Otherwise VFR conditions expected for the rest of the
taf period. SW winds will be 10-15kts with gusts as high as 25kts
throughout the day, with some weakening during the overnight
hours.
&&
.PREV DISCUSSION...(ISSUED 358 AM CDT THU JUL 7 2016
SHORT TERM...Today Through Friday Night
Similar setup to yesterday across the region with surface high
pressure in place to the southeast and low pressure noted across the
Southern Plains. Two MCS`s noted across the region with the first
impacting Tennessee/Kentucky and the second moving out of SE
Nebraska into northeastern Kansas.
Should see fewer impacts to the forecast area from upstream MCS in
Kansas due to more northerly location and easterly trajectory. Early
morning HRRR runs attempt to initiate some shower and thunderstorm
activity across E Oklahoma with a weak shortwave in the mean flow
and shift this activity toward Arkansas throughout the day. No
activity has manifested itself as of 09z so will keep forecast
dry attm though wouldn`t be surprised to see at least a few
isolated showers develop.
SW flow at the surface will be in place again today and winds will
be enhanced due to increased pressure gradient. Wind speeds will
likely be aoa 12-18mph with gusts as high as 25mph at times. The
other notable mention of the day goes to heat index values across
the state. With dewpoints in the 70s and temps cranking into the
mid to upper 90s, another run at heat index values of 105 will be
made this afternoon.
Rain chances will be in place across mainly northern Arkansas on
Friday as a surface boundary approaches from the NW. Additionally,
the H500 pattern begins to show signs of transitioning to more of an
active period with more of a NW flow expected. Will have to keep an
eye on temps/heat indices Friday as heat indices could approach
heat advisory levels once again across the southern half of the
state. Could see chances for a more notable thunderstorm complex
approaching the state from the northwest late Friday night.
LONG TERM...Saturday Through Wednesday
As a ridge of high pressure weakens over the southeast United
States, a cold front will be allowed to drop through the Ohio and
Tennessee Valleys during the upcoming weekend. The front may
actually make it into northeast Arkansas. Isolated to scattered
showers and thunderstorms are in the forecast. Given more clouds,
it will be slightly cooler.
A few storms may be severe as the front nears the region. Damaging
winds and hail will be the main concerns. An organized severe
weather event is not expected at this point. Heavy downpours in the
northeast half of the state may result in localized flash flooding.
Heading into early next week, a big trough of low pressure will be
noted out west. This will cause ridging farther east, and the front
will be forced to move away from Arkansas to the north. The
heat will return, and precipitation chances will decrease.
Temperatures will be near to a little above average for much of the
period. Readings may be a touch below average toward the
Missouri border this weekend near the aforementioned front.
&&
.LZK Watches/Warnings/Advisories...
Heat Advisory from 10 AM this morning to 8 PM CDT this evening
FOR Arkansas-Bradley-Calhoun-Clark-Cleburne-Cleveland-Conway-
Dallas-Desha-Drew-Faulkner-Garland-Grant-Hot Spring-Independence-
Jackson-Jefferson-Johnson-Lincoln-Logan-Lonoke-Monroe-Montgomery-
Ouachita-Perry-Pike-Polk-Pope-Prairie-Pulaski-Saline-Scott-Van
Buren-White-Woodruff-Yell.
&&
$$
Aviation...226
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
701 AM CDT THU JUL 7 2016
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 316 AM CDT THU JUL 7 2016
Once again the models have struggled to show where the MCS will
track with the ARW and NMM appearing to have some idea of the
location but 3 to 4 hours off on the timing. Water vapor imagery
shows a synoptic scale upper wave moving into the northern plains
while profiler hint at another MCV in eastern NEB. At the surface,
low pressure was analyzed over eastern CO and a meso high from
this morning`s convection was noted over the mid MO river valley.
With the MCS tracking across northeast KS this morning, the forecast
is based on the expected outflow pushing into east central KS this
morning before retreating back to near the KS river. This boundary
could also be reinforced by the late afternoon be synoptic pressure
rises from the upper shortwave moving across the northern plains.
With this in mind, have highs in the lower 90s across northern KS
with mid to upper 90s over east central KS. There is a fair amount
of uncertainty in this temp forecast. With the models showing a poor
track record with the nocturnal convection, confidence in exactly
where the surface boundaries end up is low. As for the possible heat
and humidity, there is a concern that I may be a little high with
dewpoints this afternoon given the convection overturning the
airmass now. Heat indices could be around 105 along and south of the
KS river but think I`ll wait to see where the outflow ends up to get
a better idea of where a heat advisory may be needed.
Precip chances through the afternoon are expected to be low but not
zero. Models strengthen the mid level EML with 700MB temps around
+17. This would be a substantial cap to a surface parcel. Have held
onto some 20 to 30 percent POPs because models bring the surface
trough into east central KS which may have enough convergence along
it for an isolated storm during the heat of the day. Overnight, the
low level jet is progged to be veered to the west southwest so
convergence along the boundary would appear to be minimal. So again
will only keep a small chance POP. But given the recent track record
of the models confidence in the forecast is below average.
.LONG TERM...(Friday through Wednesday)
Issued at 316 AM CDT THU JUL 7 2016
Friday into the weekend, have kept slight chance POPs south of I-70
for the day on Friday as a stationary boundary should stay set up
over southern KS. Weak quasi-zonal to northwest flow will be set up
over the region, so as we head into the weekend, there may be some
very sublte shortwaves and that advect out of the Northern and
Central Rockies vicinity over the region and help provide additional
lift over weak surface convergence to spark a few showers and
possibly thunderstorms as a conditionally unstable atmosphere sets
back up over northeastern KS. Very difficult at this time to
eliminate small chance POPs out of any time frame due to possible
convection developing in association with this boundary. Most
precip would likely be all elevated and weak shear would limit
organization. By the end of the weekend, weak ridging builds into
the region and late Sunday would probably be a time where precip
chances could be lowered in future updates at least looking ahead
right now.
Mean Westerlies will continue to reside to the north over the
northern tier of the CONUS. By Monday, a deepening North Pac Low
digs into the Intermountain West and begins to impact the Central
Plains Monday night into Tuesday time frame as initial weak lead
shortwaves impact northeastern KS area. This brings back a
reasonable increase in POPs, but still slight to chance only as
coverage isn`t high confidence at this time. Finally, another weak
cold front arrives day time frame Tuesday and as the previously
mentioned North Pac Low lifts into the Northern Plains and Central
Canada, a stationary boundary is left behind and probably gives
reasonable chances of off and on precip and some unorganized storms
through mid week and could finally exit the region by Thursday.
Continued WAA into this time frame should bring dewpoints back into
the upper 60s and lower 70s consistently with surface temps into the
low to perhaps mid 90s. Heat indices will again likely rise into
the low 100s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 654 AM CDT THU JUL 7 2016
For the 12Z TAFs, ongoing thunderstorms continue to move through
the area and over the TAF sites with reasonably good confidence
until around mid morning time frame. Conditions improve into the
afternoon before FROPA this evening. Until then winds will
generally have a southerly...southeasterly component and gust up
to the low 20kt range. Winds shift to the northwest after FROPA.
Not expecting significant CIG/VIS degradation outside of the TSRA
activity.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Drake
AVIATION...Drake
[top]
Area Forecast Discussion
National Weather Service Goodland KS
518 AM MDT THU JUL 7 2016
.SHORT TERM...(Today through Saturday night)
Issued at 251 AM MDT Thu Jul 7 2016
Early morning WV imagery and RAP upper level analysis shows a zonal
pattern across the Central Rockies with an elongated ridge across
the southern plains. A stronger trough is digging into the northern
plains from the Northern Rockies. A few weaker shortwave troughs are
rotating through the High/Central Plains.
Early this morning: A thunderstorm complex that developed late
evening/early this morning has transitioned well east of our CWA,
however thunderstorm activity has continued to develop where nose of
LLJ/WAA interacted with lingering outflow boundary. Trend has been
towards activity to diminish in intensity/coverage as it transitions
east, and current activity should be outside of our CWA within the
next 1-1.5 hr. Pattern could still support isolated thunderstorm
redevelopment in our north or east through day break with deep moist
flow and elevated CAPE lingering, so timing was adjusted to account
for this.
Today-Tonight: Shortwave trough in the northern plains has trended
faster than earlier guidance had indicated, with 00Z guidance
picking up on current trends. With faster trough passage in the
northern plains FROPA is now shown to move through our CWA during
the day today, with some faster members showing it south of our CWA
by midday. This obviously impacts high temps, but also raises the
possibility for isolated showers or thunderstorms within the frontal
zone if cap were to weaken sufficiently. Guidance does show moisture
profiles (above surface) drying out, and this does lower overall
confidence at the very least in coverage. Latest trends in short
range and high resolution guidance is to keep our CWA dry through
most of the day, with better chances late afternoon through the
evening as activity along the Cheyenne ridge transitions southeast
through the mean flow impacting our north and eventually our east.
I also trended Highs downward to account for earlier FROPA.
Friday-Saturday night: Initially a post frontal air mass Friday
should support highs closer to seasonal normals around 90F. H5 ridge
builds into the Plains, with south-southwest flow supporting above
normal high temperatures returning Saturday. Pattern still allows
for weak shortwave trough passages and Gulf moisture interacting
with surface features (mainly lee trough) to produce
shower/thunderstorm chances over our CWA through these periods.
Guidance continues to show overlapping precip signals, particularly
Friday and Saturday evenings. Main uncertainty will be position of
surface features that will act as focal points for initiation,
followed by evolution of any convective clusters that may develop.
1 to 1.5" PWATs and periods of possible training or slower storm
motions could result in elevated flash flood threats, High CAPE
values and effective shear in the 30-40kt may also support
wind/large hail threats.
.LONG TERM...(Sunday through Wednesday)
Issued at 251 AM MDT Thu Jul 7 2016
Somewhat unsettled weather is expected during the extended period
with intermittent chances for precipitation, along with near
seasonal temperatures.
On Sunday, upper level ridging progresses eastward from the Plains
as an upper closed low moves further over the Pacific Northwest.
Southwesterly flow develops aloft across the region, with the ridge
over the Upper Midwest and trough over the western CONUS, and
moisture filters towards the High Plains. Mainly dry conditions are
anticipated.
The associated low pressure system over the northern Plains
strengthens on Monday as the upper trough advances east.
Thunderstorm chances return to the region, with a better chance
Monday night when a stronger disturbance passes through the flow.
Thunderstorms continue to be possible Tuesday night and Wednesday as
another disturbance impacts the High Plains and the upper low makes
its way to central Canada, bringing zonal flow to the area.
Temperatures in the upper 80s to mid 90s are forecast throughout
the period. Lows appear to range within the mid 50s to low 70s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 517 AM MDT Thu Jul 7 2016
Lingering low level moisture associated with weak easterly flow
ahead of approaching cold front could support fog/stratus at both
KGLD and KMCK terminals this morning. While short range and high
resolution guidance does show this increase in low level moisture
no guidance is indicating drops below VFR at this time.
Confidence is not high enough to indroduce in TAFs at this time.
A complication could be the increased mixing from exiting
thunderstorm activity east of KMCK and a deparing LLJ preventing
fog formation. Will need to monitor, but will hold off on
introducing lower condtions at this time.
A cold front will pass through the region by midday with
at least a brief period (if not 6 hr period) of gusty north winds
imediately behind the front, followed by a shift and decrease in
winds to the northeast and then east this evening. Isolated
thunderstorms may be possible this afternoon/evening (mainly at
KMCK), however confidence/coverage is too low to include mention
in TAFs at this time.
&&
.GLD Watches/Warnings/Advisories...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JBH
AVIATION...DR
Area Forecast Discussion
National Weather Service Little Rock AR
252 PM CDT THU JUL 7 2016
.DISCUSSION...
Main concerns in this forecast cycle are chances of convection
each day, and if any would be strong to severe storm. Also due to
heat and humidity, heat advisories may be needed.
Earlier convection over northern AR associated with MCV moved
through southern MO and is now well east. It did develop isolated
convection to as far south as central AR. Also, the convection was
associated with short wave energy moving through the northwest
upper flow. Breezy south to southwest winds of 10 to 20 with gusts
to 25 mph across AR have been seen today, but have overall
remained below lake wind advisory levels. Temperatures have made
it to the 90s today over central to southern AR, while 70s to 80s
over the convection areas of northern AR. Heat index values have
reached from 100 to around 105 degrees over most locations.
&&
.SHORT TERM...Today Through Friday Night
Forecast will start with a chance to slight chance of late
afternoon to evening convection over northern to central AR. After
sunset, all convection is expected to weaken and dissipate. Late
tonight, a frontal boundary is forecast to sag southeastward
toward AR, and chances of convection come back in the forecast for
mainly northern areas Friday, then the northern half on Saturday.
Also at this time, due to in-place moisture and instability,
along with some lift, SPC has issued a marginal to slight risk of
severe storms for the northern half of AR. Damaging winds and
large hail will be the primary threats. Temperatures on Friday
will be similar to Thursday, but heat index values are only around
105 in spots. At this time will hold off on any advisory for
Friday. Likewise, surface wind speeds will remain elevated on
Friday, but as the front sags south, gradient will be not as
likely to reach lake wind advisory levels.
&&
.LONG TERM...Saturday Through Thursday
Saturday and Sunday...
Model guidance is consistent in indicating that a weak shortwave
trough will move southeast towards Arkansas on Saturday...spreading
weak large scale forcing for ascent over southern Missouri and
northern Arkansas Saturday afternoon. In addition to supplying some
weak large scale ascent...this trough is likely to force the
persistent baroclinic zone/nearly stationary front currently located
near a Kansas City to Paducah line to the southwest towards northern
Arkansas.
Forecast guidance indicates that a ridge of low-level theta-e will
consolidate along this stationary front as it will effectively act
like a deformation zone in the low-level flow field with the axis of
convective enhancement oriented along the axis of the frontal
boundary. This flow field configuration should keep a steady
supply of warm and humid air flowing into this theta-e ridge
throughout the day on Saturday...setting the stage for a favorable
corridor for scattered to numerous thunderstorms from Saturday
through Saturday evening.
This corridor of storms is likely to remain focused along the
Missouri/Arkansas border...however the more storms that develop
along the boundary...the higher the potential for the boundary to sag
farther south on Saturday. Went ahead with 40-60 POPS from northern
to central Arkansas on Saturday to account for this set up. This
type of environment supports a threat for flash flooding...however
at this time the forcing looks a bit to weak to consider a flash
flood watch. Will watch the evolution of this environment closely in
the coming days.
The largest source of uncertainty for this forecast period is what
will happen to the shortwave trough on Sunday into Sunday night.
Forecast model guidance indicates that the upper trough will
intensify (depending on where you look) and almost become a cut off
low by Sunday afternoon over the MO/AR border. The intensification
of this trough may not take place though the strength of this trough
appears to be dependent upon diabatic contributions which convective
parameterizing models can struggle with when the primary diabatic
contributer is latent heat release from convection. Taking a
vertical cross section through the model depiction of the cut off
low reveals a potential vorticity distribution characterized by a
sudden intensification in mid-level PV and a sudden decrease in PV
at the tropopause level. This signal is a classic depiction of the
creation/destruction cycle of PV associated with latent heat release
in the troposphere. It is certainly possible that the models are
right with this forecast...but this process essentially means that a
large and sustained cluster of convection is responsible for
intensifying the "upper" trough. If that convection is misplaced or
weaker than expected it will have a dramatic effect on the remainder
of the forecast as the upper level trough will actually be much
farther downstream.
Because the boundary is expected to remain quasi-stationary on
Sunday...favored the GFS forecast for an intensifying mid-level PV
anomaly/trough with this forecast and kept POPs high across northern
and central Arkansas on Sunday. Keep in mind that if convection is
not as extensive or long-lived on Saturday that the Sunday
convection will likely be displaced pretty far off to the southeast
on Sunday. At any rate...the NAM/GFS/ECMWF all offer up a similar
type of dynamic solution this weekend...with slight differences in
timing and intensity of course. Assuming these models are
accurate...another round of scattered to numerous showers and
thunderstorms are likely across central and northern Arkansas Sunday
into Sunday night.
Monday through Thursday...
With quite a bit of uncertainty in the forecast just this weekend...
the forecast for showers and thunderstorms across Arkansas on Monday
is fairly low at this time. The shortwave trough/mid-level PV
anomaly should have moved east or southeast of Arkansas by
Monday...so anticipate that the coverage of any showers or storms
will be much lower on Monday compared to this weekend. If the
boundary remains in tact this feature by itself could set off a
focused area of showers and storms Monday afternoon. Kept POPs in
the 20 to 30 percent range for now on Monday with highest confidence
in the upper trough being off to the east limiting the coverage of
precipitation.
The remainder of the week looks to remain warm with low rain chances
each day. Kept POPs in the 10 to 20 percent range each day for now
with no synoptic features evident in the forecast near Arkansas for
the middle of next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Batesville AR 95 78 94 75 / 40 30 40 30
Camden AR 97 77 96 78 / 20 20 10 20
Harrison AR 93 76 90 72 / 50 20 50 50
Hot Springs AR 96 79 95 77 / 20 20 20 30
Little Rock AR 96 78 96 78 / 20 20 20 30
Monticello AR 96 78 96 79 / 20 20 10 20
Mount Ida AR 95 78 93 75 / 20 20 20 30
Mountain Home AR 95 76 91 73 / 60 30 50 50
Newport AR 95 78 95 76 / 40 30 40 30
Pine Bluff AR 96 77 94 78 / 20 20 20 20
Russellville AR 98 77 94 76 / 30 20 20 40
Searcy AR 96 77 95 76 / 30 20 20 30
Stuttgart AR 96 77 95 78 / 20 20 20 20
&&
.LZK Watches/Warnings/Advisories...
Heat Advisory until 8 PM CDT this evening FOR Arkansas-Bradley-
Calhoun-Clark-Cleburne-Cleveland-Conway-Dallas-Desha-Drew-
Faulkner-Garland-Grant-Hot Spring-Independence-Jackson-Jefferson-
Johnson-Lincoln-Logan-Lonoke-Monroe-Montgomery-Ouachita-Perry-
Pike-Polk-Pope-Prairie-Pulaski-Saline-Scott-Van Buren-White-
Woodruff-Yell.
&&
$$
Short Term...59 / Long Term...66
Area Forecast Discussion...Updated for Aviation
National Weather Service Little Rock AR
1215 PM CDT THU JUL 7 2016
.AVIATION...
Overall VFR flight conditions are expected. Patchy MVFR may be seen
especially associated with showers or isolated thunderstorms. Winds
are expected to be southeast to southwest at 10 to 20 mph with some
gusts to around 25 mph in spots. After sunset, winds will lower to 5
to 15 mph. Tonight, isolated convection may be seen over northern
Arkansas and affect KHRO and KBPK Tafs. Winds will lower to mainly
below 10 mph. (59)
&&
.Prev Discussion.../ Issued 1000 AM CDT THU JUL 7 2016
Earlier update to add scattered convection over northern AR. Complex
over MO has helped develop this convection associated with short
wave energy moving through the northwest upper flow. Breezy south to
southwest winds of 10 to 20 with gusts to 25 mph across AR. Will
monitor for possible lake wind advisory. Otherwise, temperatures
will warm to the 90s today, and with the added humidity, heat index
values will reach around 105 degrees. A heat advisory is in effect
for most of AR except the northern areas. Late morning update will
fine tune convection chances, possibly adding a bit more southern
areas in slight chance area. (59)
&&
.PREV DISCUSSION...(ISSUED 358 AM CDT THU JUL 7 2016
SHORT TERM...Today Through Friday Night
Similar setup to yesterday across the region with surface high
pressure in place to the southeast and low pressure noted across the
Southern Plains. Two MCS`s noted across the region with the first
impacting Tennessee/Kentucky and the second moving out of SE
Nebraska into northeastern Kansas.
Should see fewer impacts to the forecast area from upstream MCS in
Kansas due to more northerly location and easterly trajectory. Early
morning HRRR runs attempt to initiate some shower and thunderstorm
activity across E Oklahoma with a weak shortwave in the mean flow
and shift this activity toward Arkansas throughout the day. No
activity has manifested itself as of 09z so will keep forecast
dry attm though wouldn`t be surprised to see at least a few
isolated showers develop.
SW flow at the surface will be in place again today and winds will
be enhanced due to increased pressure gradient. Wind speeds will
likely be aoa 12-18mph with gusts as high as 25mph at times. The
other notable mention of the day goes to heat index values across
the state. With dewpoints in the 70s and temps cranking into the
mid to upper 90s, another run at heat index values of 105 will be
made this afternoon.
Rain chances will be in place across mainly northern Arkansas on
Friday as a surface boundary approaches from the NW. Additionally,
the H500 pattern begins to show signs of transitioning to more of an
active period with more of a NW flow expected. Will have to keep an
eye on temps/heat indices Friday as heat indices could approach
heat advisory levels once again across the southern half of the
state. Could see chances for a more notable thunderstorm complex
approaching the state from the northwest late Friday night.
LONG TERM...Saturday Through Wednesday
As a ridge of high pressure weakens over the southeast United
States, a cold front will be allowed to drop through the Ohio and
Tennessee Valleys during the upcoming weekend. The front may
actually make it into northeast Arkansas. Isolated to scattered
showers and thunderstorms are in the forecast. Given more clouds,
it will be slightly cooler.
A few storms may be severe as the front nears the region. Damaging
winds and hail will be the main concerns. An organized severe
weather event is not expected at this point. Heavy downpours in the
northeast half of the state may result in localized flash flooding.
Heading into early next week, a big trough of low pressure will be
noted out west. This will cause ridging farther east, and the front
will be forced to move away from Arkansas to the north. The
heat will return, and precipitation chances will decrease.
Temperatures will be near to a little above average for much of the
period. Readings may be a touch below average toward the
Missouri border this weekend near the aforementioned front.
&&
.LZK Watches/Warnings/Advisories...
Heat Advisory from 10 AM this morning to 8 PM CDT this evening
FOR Arkansas-Bradley-Calhoun-Clark-Cleburne-Cleveland-Conway-
Dallas-Desha-Drew-Faulkner-Garland-Grant-Hot Spring-Independence-
Jackson-Jefferson-Johnson-Lincoln-Logan-Lonoke-Monroe-Montgomery-
Ouachita-Perry-Pike-Polk-Pope-Prairie-Pulaski-Saline-Scott-Van
Buren-White-Woodruff-Yell.
&&
$$
Aviation...226
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
315 PM CDT THU JUL 7 2016
.SHORT TERM...(This Evening through Friday)
Issued at 311 PM CDT THU JUL 7 2016
Early morning convection brought a swath of rainfall northwest
through southeast across the forecast area, and left an outflow over
eastern Kansas throughout the morning hours. Temperatures now mixing
out and rising into the upper 80s and low 90s. Dewpoints also slow
to rise, with Concordia at this hour still at 66F while southern
areas increasing into the low 70s. End result will be a few hours
in our southern and eastern areas with heat indicies in the 100 to
103 range, just shy of criteria for an advisory. Satellite imagery
and wind fields show boundary over north central Kansas near the NE
border, but lift remains generally weak in this area to tap into
the instability aloft. Storms developing along the front up into
Nebraska and extending into Minnesota, with this cluster expected
to build east and southward with time. Much of our area has a
strong cap in place with 16-18C at 700mb, and with lack of a
strong source of forcing, think areas that have the best chance
for strong storms are far eastern counties on the edge of the cap
and where 850mb winds veer to the SW into the evening hours.
Enough cape, wind and steep lapse rates aloft to make wind the
primary concern with small hail also a possibility. Think that
the boundary farther to the west will have a hard time generating
precipitation, and have lower chances as you go westward into
north central Kansas.
On Friday...Front is forecast to have moved south and west of the
area. Convection is forecast to develop in western Kansas along
the front as a shortwave moves into the state. At this time think
impacts of rain chances will be primarily in our west and south,
given location of the front and some likely reinforcement of its
position from the cold pool from overnight convection.
.LONG TERM...(Friday Night through Thursday)
Issued at 311 PM CDT THU JUL 7 2016
Friday Evening through Sunday...Underneath westerly flow aloft,
an embedded impulse is progged to lift north and east from the
southwest CONUS into the central Plains Friday evening into
Saturday. Convergence along the h85 boundary Friday evening in
conjunction with a stout llj up to 30 kts will develop another
round of thunderstorms across portions of central KS. As a
shortwave trough continues eastward during the day Saturday,
thunderstorms remain possible especially along and south of the
Interstate 70 corridor where the boundary remains stationary. With
the potential for cloud cover and precipitation, highs are
generally in the mid to upper 80s. Further west, where better
mixing and lesser cloud cover resides, highs in the lower 90s are
expected. This trend continues into early evening as activity
gradually shifts southeast, creating a quiet evening for the area
with mostly cloudy skies and lows near 70. A warmer and drier
forecast is in store on Sunday as upper ridging builds overhead
while the frontal boundary edges towards Missouri. Highs are
progged in the lower 90s for Sunday.
Sunday night through Wednesday...An amplified trough is expected
to be located across the Western United States at the beginning of
the period. Weak lead waves ejecting from the base of the trough
could lead to thunderstorm development Sunday night and Monday. A
more substantial wave is depicted by both the EC and GFS on
Tuesday, however the bulk of forcing looks to go north of the
outlook area. Have Chance PoPs Tuesday afternoon and evening as a
weak surface boundary will setup in the area. This boundary in
conjunction with weak upper level forcing could provide enough
convergence for thunderstorm development. With a strong cap in
place, widespread thunderstorm development is unlikely, but if
development occurs, storms may be severe. Zonal mid-level flow
will become the dominate flow by midweek next week. With weak mid-
level waves traversing the CONUS, will have to maintain at least
slight-chance PoPs for the remainder of the period. Muggy
conditions will continue for the duration of the period as high
temperatures will remain in the low to middle 90s and dewpoints in
the 70s. This combination yields Heat Index values near 100
degrees every afternoon of the period.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1218 PM CDT THU JUL 7 2016
Main concerns in the forecasts are for wind changes as front
approaches and passes. Also a chance for strong thunderstorms to
develop in eastern Kansas and will need to monitor for possible
impact on TOP/FOE. Have added a VCTS thinking storms will be
primarily east of terminals.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Prieto
AVIATION...67
[top]
Area Forecast Discussion
National Weather Service Dodge City KS
229 PM CDT THU JUL 7 2016
...Updated Short term and Long term discussions...
.SHORT TERM...(This evening through Friday)
Issued at 227 PM CDT Thu Jul 7 2016
A cold front dropping south across southwest Kansas during the
afternoon will be located near the Oklahoma border during the
early evening hours. Models are hinting at a weak upper level
disturbance approaching from the four corners region early
tonight. Given the forecast weak CIN near this boundary, moisture
and weak instability ahead of this wave early tonight will retain
mention of small chances for convection along and south of the
Oklahoma border.
Based on some cloud cover overnight and light easterly winds
developing the latest MAV/MET guidance looks on track with lows
ranging from the mid 60s in west central Kansas to near 75 in
south central Kansas and along the Oklahoma border.
Cooler, more seasonal temperatures can be expected on Friday
given the cooling trend forecast in the 900mb to 850mb level along
with the expected cloud cover. Precipitation chances will also be
on the increase late day as moisture and lift begins to improve
across southwest Kansas. The better opportunity for precipitation
will be Friday night.
.LONG TERM...(Friday night through Thursday)
Issued at 227 PM CDT Thu Jul 7 2016
Warm air advection, moisture, and instability will improve Friday
night as another upper level disturbance approaches from the west.
Given the 0-1km moisture convergence, CAPES and 0-6km shear there
will be a chance for a few of these storms Friday night to become
severe. Hail up to half dollar and strong damaging winds will be
the main hazard. Heavy rainfall will also be an issue with these
storms Friday night given the forecast high precipitable water.
Precipitation chances for western Kansas will briefly taper off
by Sunday as the warm front lifts north and east and ridging aloft
begins to build into the West Central High Plains.
Early next week the next upper low/trough will begin to move east
across the western United states. As this next system approaches
the chance for afternoon and night time convection will begin to
increase across western Kansas. A warming trend can also be
expected early next week given the warming forecast in the 850mb
to 700mb level.
The GFS and ECMWF both move this next upper level storm system
across the central plains late Tuesday into Wednesday. As this
passes a cold front will drop south across western Kansas bringing
an end to the warming trend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1210 PM CDT Thu Jul 7 2016
As a cold front moves south into northern Oklahoma by late day a
northerly wind at around 10 knots can be expected at all three taf
sites through early tonight. Overnight these north winds will
gradually veer to the east which will begin to draw more humid air
back into the lower levels. At this time model soundings do not
indicate fog or stratus development by 12z Friday but some patchy
3 to 5sm fog does appear possible at GCK and DDC. As the moisture
and lift begins to improve early in the day an area of VFR
ceilings may begin develop near or just south and west DDC or GCK
after 12z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 92 67 95 / 10 30 30 20
GCK 69 91 67 95 / 10 20 30 20
EHA 68 91 67 97 / 20 20 20 20
LBL 69 94 68 98 / 20 20 30 20
HYS 68 88 66 90 / 20 30 50 20
P28 74 93 71 95 / 20 30 40 20
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Burgert
LONG TERM...Burgert
AVIATION...Burgert
Area Forecast Discussion
National Weather Service Goodland KS
1218 PM MDT THU JUL 7 2016
.SHORT TERM...(Today through Saturday night)
Issued at 251 AM MDT Thu Jul 7 2016
Early morning WV imagery and RAP upper level analysis shows a zonal
pattern across the Central Rockies with an elongated ridge across
the southern plains. A stronger trough is digging into the northern
plains from the Northern Rockies. A few weaker shortwave troughs are
rotating through the High/Central Plains.
Early this morning: A thunderstorm complex that developed late
evening/early this morning has transitioned well east of our CWA,
however thunderstorm activity has continued to develop where nose of
LLJ/WAA interacted with lingering outflow boundary. Trend has been
towards activity to diminish in intensity/coverage as it transitions
east, and current activity should be outside of our CWA within the
next 1-1.5 hr. Pattern could still support isolated thunderstorm
redevelopment in our north or east through day break with deep moist
flow and elevated CAPE lingering, so timing was adjusted to account
for this.
Today-Tonight: Shortwave trough in the northern plains has trended
faster than earlier guidance had indicated, with 00Z guidance
picking up on current trends. With faster trough passage in the
northern plains FROPA is now shown to move through our CWA during
the day today, with some faster members showing it south of our CWA
by midday. This obviously impacts high temps, but also raises the
possibility for isolated showers or thunderstorms within the frontal
zone if cap were to weaken sufficiently. Guidance does show moisture
profiles (above surface) drying out, and this does lower overall
confidence at the very least in coverage. Latest trends in short
range and high resolution guidance is to keep our CWA dry through
most of the day, with better chances late afternoon through the
evening as activity along the Cheyenne ridge transitions southeast
through the mean flow impacting our north and eventually our east.
I also trended Highs downward to account for earlier FROPA.
Friday-Saturday night: Initially a post frontal air mass Friday
should support highs closer to seasonal normals around 90F. H5 ridge
builds into the Plains, with south-southwest flow supporting above
normal high temperatures returning Saturday. Pattern still allows
for weak shortwave trough passages and Gulf moisture interacting
with surface features (mainly lee trough) to produce
shower/thunderstorm chances over our CWA through these periods.
Guidance continues to show overlapping precip signals, particularly
Friday and Saturday evenings. Main uncertainty will be position of
surface features that will act as focal points for initiation,
followed by evolution of any convective clusters that may develop.
1 to 1.5" PWATs and periods of possible training or slower storm
motions could result in elevated flash flood threats, High CAPE
values and effective shear in the 30-40kt may also support
wind/large hail threats.
.LONG TERM...(Sunday through Wednesday)
Issued at 251 AM MDT Thu Jul 7 2016
Somewhat unsettled weather is expected during the extended period
with intermittent chances for precipitation, along with near
seasonal temperatures.
On Sunday, upper level ridging progresses eastward from the Plains
as an upper closed low moves further over the Pacific Northwest.
Southwesterly flow develops aloft across the region, with the ridge
over the Upper Midwest and trough over the western CONUS, and
moisture filters towards the High Plains. Mainly dry conditions are
anticipated.
The associated low pressure system over the northern Plains
strengthens on Monday as the upper trough advances east.
Thunderstorm chances return to the region, with a better chance
Monday night when a stronger disturbance passes through the flow.
Thunderstorms continue to be possible Tuesday night and Wednesday as
another disturbance impacts the High Plains and the upper low makes
its way to central Canada, bringing zonal flow to the area.
Temperatures in the upper 80s to mid 90s are forecast throughout
the period. Lows appear to range within the mid 50s to low 70s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1109 AM MDT Thu Jul 7 2016
VFR conditions currently expected through the TAF period at GLD
and MCK. Moisture pooling ahead of the cold front moving through
the central high plains region has led to the development of a
ceiling of cumulus, but is expected to mostly dissipate late this
afternoon as dryer air moves in behind the front. Later in the
day, mostly between 00Z-06Z, but also continuing overnight, there
could be isolated thunderstorms and a few lingering overnight
showers that track through the region mainly along and north of
the Kansas/Nebraska border. Have not included them in the current
TAFs as probabilities are low and are not expected to be part of
the prevailing conditions at this time.
&&
.GLD Watches/Warnings/Advisories...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JBH
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1225 PM CDT THU JUL 7 2016
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 316 AM CDT THU JUL 7 2016
Once again the models have struggled to show where the MCS will
track with the ARW and NMM appearing to have some idea of the
location but 3 to 4 hours off on the timing. Water vapor imagery
shows a synoptic scale upper wave moving into the northern plains
while profiler hint at another MCV in eastern NEB. At the surface,
low pressure was analyzed over eastern CO and a meso high from
this morning`s convection was noted over the mid MO river valley.
With the MCS tracking across northeast KS this morning, the forecast
is based on the expected outflow pushing into east central KS this
morning before retreating back to near the KS river. This boundary
could also be reinforced by the late afternoon be synoptic pressure
rises from the upper shortwave moving across the northern plains.
With this in mind, have highs in the lower 90s across northern KS
with mid to upper 90s over east central KS. There is a fair amount
of uncertainty in this temp forecast. With the models showing a poor
track record with the nocturnal convection, confidence in exactly
where the surface boundaries end up is low. As for the possible heat
and humidity, there is a concern that I may be a little high with
dewpoints this afternoon given the convection overturning the
airmass now. Heat indices could be around 105 along and south of the
KS river but think I`ll wait to see where the outflow ends up to get
a better idea of where a heat advisory may be needed.
Precip chances through the afternoon are expected to be low but not
zero. Models strengthen the mid level EML with 700MB temps around
+17. This would be a substantial cap to a surface parcel. Have held
onto some 20 to 30 percent POPs because models bring the surface
trough into east central KS which may have enough convergence along
it for an isolated storm during the heat of the day. Overnight, the
low level jet is progged to be veered to the west southwest so
convergence along the boundary would appear to be minimal. So again
will only keep a small chance POP. But given the recent track record
of the models confidence in the forecast is below average.
.LONG TERM...(Friday through Wednesday)
Issued at 316 AM CDT THU JUL 7 2016
Friday into the weekend, have kept slight chance POPs south of I-70
for the day on Friday as a stationary boundary should stay set up
over southern KS. Weak quasi-zonal to northwest flow will be set up
over the region, so as we head into the weekend, there may be some
very subtle shortwaves and that advect out of the Northern and
Central Rockies vicinity over the region and help provide additional
lift over weak surface convergence to spark a few showers and
possibly thunderstorms as a conditionally unstable atmosphere sets
back up over northeastern KS. Very difficult at this time to
eliminate small chance POPs out of any time frame due to possible
convection developing in association with this boundary. Most
precip would likely be all elevated and weak shear would limit
organization. By the end of the weekend, weak ridging builds into
the region and late Sunday would probably be a time where precip
chances could be lowered in future updates at least looking ahead
right now.
Mean Westerlies will continue to reside to the north over the
northern tier of the CONUS. By Monday, a deepening North Pac Low
digs into the Intermountain West and begins to impact the Central
Plains Monday night into Tuesday time frame as initial weak lead
shortwaves impact northeastern KS area. This brings back a
reasonable increase in POPs, but still slight to chance only as
coverage isn`t high confidence at this time. Finally, another weak
cold front arrives day time frame Tuesday and as the previously
mentioned North Pac Low lifts into the Northern Plains and Central
Canada, a stationary boundary is left behind and probably gives
reasonable chances of off and on precip and some unorganized storms
through mid week and could finally exit the region by Thursday.
Continued WAA into this time frame should bring dewpoints back into
the upper 60s and lower 70s consistently with surface temps into the
low to perhaps mid 90s. Heat indices will again likely rise into
the low 100s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1218 PM CDT THU JUL 7 2016
Main concerns in the forecasts are for wind changes as front
approaches and passes. Also a chance for strong thunderstorms to
develop in eastern Kansas and will need to monitor for possible
impact on TOP/FOE. Have added a VCTS thinking storms will be
primarily east of terminals.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Drake
AVIATION...67
Area Forecast Discussion
National Weather Service Dodge City KS
1211 PM CDT THU JUL 7 2016
...Updated Aviation Discussion...
.SYNOPSIS...
Issued at 313 AM CDT Thu Jul 7 2016
A shortwave trough will traverse the northern plains today,
helping to push a weak cold front through western Kansas by
tonight. Moist upslope flow will develop behind the front tonight
and then persist into Friday. This surface front will remain over
the southern and central plains Saturday as weak upper level
ridging moves over the high plains. A large upper level trough
over the western United States Saturday and Sunday is expected to
progress eastward into the northern plains by Monday. Surface
troughing will develop in advance of this upper level system by
Sunday, with a weak cold front approaching by late Monday.
&&
.SHORT TERM...(Today and tonight)
Issued at 313 AM CDT Thu Jul 7 2016
There is some uncertainty with the speed of the aforementioned
cold front today. The RAP is faster with the front with
slightly cooler temperatures, while the NAM is a bit slower. The
HRRR is also faster. Given that the winds were already from the
northeast at Hays and Hill City as of 3 am, which is probably due
to thunderstorm outflow from storm clusters in Nebraska, it`s
likely that the faster frontal movement is correct. This would
result in 100+ temperatures being confined to the Oklahoma state
line, with cooler mid 90s or perhaps even lower 90s along
Interstate 70. Thunderstorms are not expected although there is a
very slight chance along the Colorado state line along the front
that will be trailing back to the west-northwest.
.LONG TERM...(Friday through Wednesday)
Issued at 313 AM CDT Thu Jul 7 2016
There is a chance of thunderstorms on Friday as low level upslope
flow results in high theta-e values on the cool side of the
front. These could be severe given a belt of 45kt upper level
winds and given the expected slow storm motions, resulting in good
storm top ventilation. Temperatures will be cooler, with highs
only in the lower 90s at best. There is a small chance of
thunderstorms into Saturday despite the weak upper level ridging
as the frontal boundary lingers. THe aforementioned strong upper
level trough developing over the western United States this
weekend will result in west-southwesterly mid level flow and
lee surface troughing over the high plains by Saturday and
persisting into Sunday. There is a small chance of thunderstorm
along and ahead of the surface trough, with south winds and warmer
maximum temperatures into the mid 90s. As the upper level trough
progresses into the northern plains by Monday, a weak cold front
should progress into western Kansas, resulting in continued small
thunderstorm chances.
As long as the southern edge of mid-latitude belt of westerlies
remains over Kansas, thunderstorms will be hard to rule out just
about any day. This be due to the tendency for surface fronts to
stall out across the area, along with low level moisture
convergence. Additionally, minor disturbances in the westerlies
could enhance thunderstorm chances on certain days.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1210 PM CDT Thu Jul 7 2016
As a cold front moves south into northern Oklahoma by late day a
northerly wind at around 10 knots can be expected at all three taf
sites through early tonight. Overnight these north winds will
gradually veer to the east which will begin to draw more humid air
back into the lower levels. At this time model soundings do not
indicate fog or stratus development by 12z Friday but some patchy
3 to 5sm fog does appear possible at GCK and DDC. As the moisture
and lift begins to improve early in the day an area of VFR
ceilings may begin develop near or just south and west DDC or GCK
after 12z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 98 70 92 67 / 0 10 30 30
GCK 96 69 91 67 / 0 10 20 30
EHA 101 68 91 67 / 10 20 20 20
LBL 101 69 94 68 / 10 20 20 30
HYS 95 68 88 66 / 0 10 30 50
P28 105 74 93 71 / 10 20 30 40
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...Finch
SHORT TERM...Finch
LONG TERM...Finch
AVIATION...Burgert