Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/08/16
Area Forecast Discussion
National Weather Service Little Rock AR
711 PM CDT THU JUL 7 2016
.AVIATION...08/00z Taf Cycle
Look for VFR conds to cont thru much of pd. Sct-bkn low clouds wl
again dvlp toward sunrise Fri...mainly acrs CNTRL and SRN AR...
resulting in ocnl MVFR cigs. Hi-Res model data conts to suggest a
complex of storms forming forming later tngt acrs SRN KS...
eventually working SEWD into parts of NW AR Fri mrng. Included
PROB30 groups at KHRO and KBPK to account for any storms that may
form along residual small scale bndry`s later in the day. /44/
&&
.PREV DISCUSSION...(ISSUED 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.
&&
.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.
&&
$$
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 Northern Indiana
830 PM EDT THU JUL 7 2016
.SYNOPSIS...
Issued at 355 PM EDT Thu Jul 7 2016
There is a chance of showers and thunderstorms into tonight.
Otherwise hot and humid conditions will continue into Friday in
advance of a cold front. Some storms are possible Friday, mainly
across far northeast Indiana and northwest Ohio. Dry, cooler, and
less humid conditions are then expected for the weekend. Low
temperatures tonight will be in the lower 70s. High temperatures
Friday will range from 85 to 90.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 352 PM EDT Thu Jul 7 2016
An upper level system was over Illinois and was moving into Indiana
this afternoon. Early morning fog and low clouds had stabilized the
area this morning over central Indiana, although northern Indiana
was able to destabilized under mostly sunny skies into this
afternoon. A large storm complex had developed over western
Tennessee and western Kentucky this afternoon where CAPE values had
risen above 3000 J/kg. To the north of this area, convection was
extremely limited through 330 pm EDT, although some showers had
managed to form near Ft Wayne where CAPE values had risen above
1500. Not overly optimistic about storm chances tonight given
subsidence behind the first wave. However, an upper level jet and
sufficient moisture should be adequate for scattered storms
overnight as the next wave approaches. The storm prediction center
has expanded the slight risk for severe storms Friday across all of
Ohio and most of Indiana and Lower Michigan. The extent of severe
weather chances Friday will depend greatly upon the development and
extent of convection tonight and location of outflow boundaries
Friday morning
&&
.LONG TERM...(Friday Night through Thursday)
Issued at 352 PM EDT Thu Jul 7 2016
Cooler and drier air will be spreading across the area Friday night
behind the cool front. A ridge of high pressure will build into the
area this weekend bringing more comfortable conditions with less
humidity. Warmer and more humid conditions will return early next
week as the return flow of moisture begins and as disturbances move
across the northern CONUS in high zonal flow aloft. Kept a slight
chance for a thunderstorm Tuesday, and then a better chance
Wednesday and Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 829 PM EDT Thu Jul 7 2016
Uncertain nr term stemming fm poor/wavering shrt term guidance.
Broad view shows compact/intact mcv ovr sw Chicago fm earlier
decayed mcs. Recent new dvlpmnt extends south of the ftr within
fvrbl instability wedge which also extends ewd into wrn OH.
Upstream bkn line of elevated convn has struggled this aftn likely
owing to warm mid lvl temps and poor mid lvl lapse rates but
uptick in storms nr KRZL suggests that cells have now rooted into
the more unstable bndry lyr and portents at least some ewd
organization psbl this evening. Will cont to monitor.
Otrws beyond nr term pd...fog/stratus likely to redvlp in wake of
this sys overnight as moist bndry lyr persists and augmented to some
degree by addnl rain through this evening. Good consensus signal
to introduce an IFR mention at least.
&&
.IWX Watches/Warnings/Advisories...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Skipper
SHORT TERM...Skipper
LONG TERM...Skipper
AVIATION...T
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Area Forecast Discussion
National Weather Service Indianapolis IN
732 PM EDT THU JUL 7 2016
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 204 PM EDT Thu Jul 7 2016
A frontal boundary lingering over south Indiana will remain the
focus for precipitation the in the next 24 hours as an upper level
weather disturbance passes across Indiana. This in combination
with the the very warm and humid air mass in place across Indiana
should result in chances for showers and thunderstorm Tonight and
on Friday.
Cooler and less humid air will arrive in central Indiana on friday
afternoon and evening as a cool front passes across the state.
High pressure is then expected to sag south from Canada into the
Ohio Valley for the weekend...providing dry and less humid
weather.
Chances for storms will return by Tuesday and Wednesday as a frontal
boundary moves into the area.
&&
.NEAR TERM /Tonight/...
Issued at 204 PM EDT Thu Jul 7 2016
Radar Trends early this afternoon show a convective cluster over
eastern Illinois rapidly diminishing as it make slow progress
eastward. IR shows Cloud tops continuing to warm...typical diurnal
trend with weakening MCS`s. Cirrus blow off shield from the dying
MCS was spreading across central Indiana...inhibiting heating and
holding temps in the mid 70s. Warm and humid air mass still
remains in place ahead of the system...with dew points in the 70s
across Indiana.
Models tonight suggest best shear and instability to remain
across far southwest Indiana and western Kentucky. Rapid refresh
suggests development across the southwest parts of the stats
through Early evening...while another cluster pushes across
central Indiana near 00z. Confidence in this is low as cloud cover
is preventing heating and instability. After this wave departs
this evening...once again best forcing appears lost while the
very warm and humid air mass remains.
Thus any afternoon heating...a redevelopment cannot be ruled out...but
as clouds linger...chances for storms continue to diminish. Thus
will include nearly 50 pops through the early evening to account
for any pop up storms that could develop due to potential heating.
Will then trend pops lower overnight as no forcing mechanism
remains.
&&
.SHORT TERM /Friday through Sunday/...
Issued at 204 PM EDT Thu Jul 7 2016
On Friday the GFS and NAm suggest and upper short wave pushing
through the Great Lakes and dragging an associated cool front
across Indiana during the afternoon hours. With the expected very
warm and moist air mass in place and this forcing
available...expect afternoon showers and storms to develop along
and ahead of the front. Thus will trend pops on Friday higher
than MAVMOS. Given the very warm 850mb temps and warm air
advection ahead of the front...along with more sunshine
expected...will trend highs warmer than guidance at most spots.
Dry air and subsidence is expected to build in the wake of the
front on Friday night and into Saturday. By Friday night forecast
soundings suggest a dry column and best moisture departs near 00z.
May need to include some evening pops across the eastern parts of
the forecast area for the first few hours of the evening to
account for any lingering convection along and near the front.
A blend on Friday night lows for the changing air mass should work
nicely.
GFS and Nam then suggest high pressure settling over the region
for Saturday and Sunday...providing northerly winds along with
cooler temps and lower humidity. Forecast soundings remain dry
during that period with mid level capping and unattainable convective
temperatures. Thus will trend toward mostly sunny days and mostly
clear nights. A blend of temps will suffice.
&&
.LONG TERM /Sunday Night through Wednesday Night/...
Issued at 231 PM EDT Thu Jul 7 2016
Ridging over the Midwest early in the period will result in dry
conditions for Sunday night and across most of central Indiana on
Monday. The exception will be across the southern portions of the
forecast area on Monday evening as a warm front approaches from the
southwest. This front is in association with a low pressure system
tracking across Canada. This system will be responsible for
unsettled weather through mid-week as it tracks eastward. As a
result, latest Superblend initialization is trending toward low pops
from Tuesday through Wednesday night. Temperatures through the
period will be at or above normal with highs in the mid 80s to low
90s and overnight lows in the mid 60s to low 70s.
&&
.AVIATION /Discussion for 080000Z TAF issuance/...
Issued at 722 PM EDT Thu Jul 7 2016
Low confidence forecast tonight for the taf sites. Convection
currently over northeast Illinois/northwest Indiana progged by
some hi res output to move southeast into KLAF and KIND over the
next few hours. However the extent of the activity has been
overforecast by these same models for several hours. Since current
placement of echoes looks pretty good, just overdone in the HRRR,
will go ahead and include VCTS at KLAF through 2z with a tempo in
for tsra there. At KIND will go with timing of HRRR and include
VCTS 2-5z, which is likely longer than it would be needed if it
does come to fruition. At KBMG included a VCSH as the line may not
get that far south but even if it does could run out of
instability before then.
For all these sites, MOS guidance and SREFs suggest some MVFR
visibilities during the overnight and given dew points over 70
degrees thought this was reasonable. With the warm front and
surface low staying north of the area don`t expect visibilities to
drop lower than that.
For Friday, more convection is possible. Included a VCSH for KIND
and KBMG after 21z but confidence is still pretty low. Light
southerly winds tonight will shift to westerly 5-12 kts late
Friday morning into Friday afternoon.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....TDUD
AVIATION...CP
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
331 PM CDT WED JUL 6 2016
.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 nothern 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 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1210 PM CDT WED JUL 6 2016
Very little change expected through mid day Thursday. Expect
southerly winds 5 to 15 kts and VFR conditions. Very low
probabilities of late night/early morning thunderstorms, most
likely staying well to north of TAF sites.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...GDP
LONG TERM...Omitt
AVIATION...GDP
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1146 PM CDT TUE JUL 5 2016
...Update to aviation forecast discussion...
.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 06Z TAFS through 06Z Wednesday Night)
Issued at 1146 PM CDT TUE JUL 5 2016
Have narrowed down VCTS a bit, with some uncertainty remaining on
coverage and timing even in the next few hours. Wind shear
continues to look to weak and short lived for a mention. VFR
conditions otherwise anticipated.
&&
.TOP Watches/Warnings/Advisories...
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...65
Area Forecast Discussion
National Weather Service Little Rock AR
354 AM CDT FRI JUL 8 2016
.SHORT TERM...Today Through Saturday Night
Once again, surface analysis indicates ridge of high pressure
located southeast of the state with low pressure situated over
the TX/OK panhandles. A frontal boundary stretches from the TX/OK
panhandles northeastward toward Chicago. Several series of
thunderstorm complexes can be seen on NWS radar network early this
morning, from northern Oklahoma into southern Kansas as well as
across northern Arkansas into southern Missouri.
Better rain chances will be in the forecast during the short term
period as the upper ridge across the southern US begins to retreat
westward a bit providing more of a NW flow aloft over the state.
Several upper level shortwave troughs will move along this flow
and interact with the boundary at the surface which will be
positioned across northern Arkansas the next few days. Potential
is there for remnant thunderstorm complexes to move over the state
Saturday and Sunday morning, similar to what has been seen across
Kansas and Missouri the last few days.
Even with rainfall chances in the forecast and more widespread
cloud cover noted, only northern Arkansas will see a legitimate
break from summertime heat. It will still be quite warm across
central and southern areas. Winds will be enhanced again today
with breezy conditions out of the southwest. Even lighter winds
expected Saturday.
&&
.LONG TERM...Sunday Through Thursday
A weakness in the ridge of high pressure over the southeast United
States coupled with a storm system aloft over southern Missouri
will yield isolated to scattered showers and thunderstorms in
Arkansas Sunday. At the surface, a weak stationary front will be
draped across northeast sections of the state, which is close to
the periphery of the ridge. Precipitation coverage will be
greatest north/east of Little Rock nearest the front.
A few storms may be severe. Damaging winds and hail will be the main
concerns. An organized severe weather event is not expected. 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
wobble from the Rockies to the upper Midwest. 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. As the period begins, readings may be a touch below average
toward the Missouri border near the aforementioned front.
&&
.PRELIMINARY POINT TEMPS/POPS...
Batesville AR 93 74 87 72 / 40 30 50 60
Camden AR 97 77 96 75 / 10 20 30 30
Harrison AR 89 71 84 69 / 50 50 50 50
Hot Springs AR 95 77 92 75 / 20 30 40 30
Little Rock AR 96 78 93 76 / 20 30 40 40
Monticello AR 96 79 95 76 / 10 20 30 30
Mount Ida AR 94 75 92 73 / 20 30 40 30
Mountain Home AR 90 72 85 70 / 50 50 50 60
Newport AR 94 75 88 73 / 40 30 50 50
Pine Bluff AR 95 78 92 75 / 20 20 40 30
Russellville AR 94 76 90 74 / 20 40 50 40
Searcy AR 95 76 91 73 / 20 30 50 50
Stuttgart AR 95 77 92 75 / 20 20 40 40
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Short Term...226 / Long Term...46
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
1225 AM CDT FRI JUL 8 2016
.UPDATE...
Updated to include 06z aviation discussion.
&&
.AVIATION...
Showers and thunderstorms slowly moving SE out of SW MO and SE KS
this morning may bring vicinity SH/TS activity to northern AR
terminals this morning as they dissipate. Otherwise, MVFR
ceilings expected across central/southern AR around daybreak once
again with primarily VFR conditions seen otherwise. Winds will be
out of the SW again with speeds of 8-12kts and gusts to 20kts at
times.
&&
.PREV DISCUSSION...(ISSUED 711 PM CDT THU JUL 7 2016
)
AVIATION...08/00z Taf Cycle
Look for VFR conds to cont thru much of pd. Sct-bkn low clouds wl
again dvlp toward sunrise Fri...mainly acrs CNTRL and SRN AR...
resulting in ocnl MVFR cigs. Hi-Res model data conts to suggest a
complex of storms forming forming later tngt acrs SRN KS...
eventually working SEWD into parts of NW AR Fri mrng. Included
PROB30 groups at KHRO and KBPK to account for any storms that may
form along residual small scale bndry`s later in the day. /44/
PREV DISCUSSION...(ISSUED 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.
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Aviation...226
Area Forecast Discussion
National Weather Service Little Rock AR
711 PM CDT THU JUL 7 2016
.AVIATION...08/00z Taf Cycle
Look for VFR conds to cont thru much of pd. Sct-bkn low clouds wl
again dvlp toward sunrise Fri...mainly acrs CNTRL and SRN AR...
resulting in ocnl MVFR cigs. Hi-Res model data conts to suggest a
complex of storms forming forming later tngt acrs SRN KS...
eventually working SEWD into parts of NW AR Fri mrng. Included
PROB30 groups at KHRO and KBPK to account for any storms that may
form along residual small scale bndry`s later in the day. /44/
&&
.PREV DISCUSSION...(ISSUED 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.
&&
.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.
&&
$$
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
340 AM CDT FRI JUL 8 2016
.SHORT TERM...(Today and Tonight)
Issued at 326 AM CDT FRI JUL 8 2016
An amplified upper level trough across the upper midwest early this
morning will move east across the eastern Great Lakes Tonight. The
upper flow across eastern KS will weaken and shift to the northwest
through Tonight as an upper level ridge amplifies across the high
plains.
At the surface a weak cold front front extended from northwest MO,
southwest through Topeka, then west southwest across western KS. An
out flow boundary extended from northwest OK, northeast into south
central KS, then extended east across southeast KS. North of the
boundary a few showers and thunderstorms continued to develop across
southeast KS early this morning. A complex of storms that developed
across the northern TX PNHDL has amplified an MCV across southwest
KS.
Most models show the weak front becoming stationary south of the CWA
through the mid morning hours with frontolysis occurring through the
afternoon hours across western KS. The NAM and GFS models show the
MCV over southwest KS shifting east across the southern counties of
the CWA through the late morning and afternoon hours which may
provide enough ascent for showers and thunderstorms to develop. If
these solution are accurate, then there will be chances for showers
and thunderstorms south of I-70, beginning across the southwest
counties during the late morning hours and expanding east across the
southern half of the CWA during the early and mid afternoon hours.
The mesocale models, such as the HRRR, WRF and RAP show the MCV
weakening and no precip developing through the day.
Highs today will reach the upper 80s to lower 90s with heat indices
in the mid to upper 90s
Tonight, all the numerical models show that any complex of storms
that develop across eastern CO during the evening hours will track
southeast across southwest KS into northern OK. There could be
enough isentropic lift after mid night on the northern and eastern
edge of the deeper moisture return across central and western KS for
scattered elevate thunderstorms to develop across the southwest and
southern counties of the CWA.
.LONG TERM...(Saturday through Thursday)
Issued at 326 AM CDT FRI JUL 8 2016
The weekend will see slight chance POPs over the area to begin
with. Weak isentropic lift sets up in the morning over northeastern
Kansas on Saturday as weak shortwaves pass overhead into the day.
Forcing is weak overall, so much of this could just result in
enhanced cloud cover rather than any widespread showers and isolated
thunderstorms. There will still be plenty of instability with
dewpoints still forecast to be in the upper 60s and low 70s. As a
North Pac Low deepens and digs into the Pacific Northwest, mid to
upper level ridging will amplify over the Central and Northern
Plains into Sunday and should see mainly dry conditions set up over
the region with good mixing into the afternoon. Therefore,
expecting temps to rise into the low and possibly mid 90s. This
will bring heat index values up to around or into the low 100s. Not
anticipating headlines at this time for an advisory though. It may
be something to watch if we can hold off more cloud cover and temps
rise a bit more.
Monday into the Monday night time frame, the North Pac Low will
deepen and take on a negative tilt as it lifts into the Northern
Plains. A modified cold boundary will move into the Central Plains
and stall out as this system lifts into Central Canada. Greatest
chance POPs will likely be overnight Monday as the best shear zone
advects overhead with the mean trough. At least this appears to be
the best chance for any organized storms to form. A strong EML will
have also set up over the Central Plains, so it may be too capped
for development to take place, but mainly elevated storms look like
the best possibility which if they form could create some strong
gusty winds and hail. Still difficult to eliminate precip chances
out of subsequent periods as quasi-zonal flow regime sets up and
weak impulses traverse overhead. Still looks like possibility
remains for off and on showers and storms into the Friday time frame
with a stationary boundary likely lingering over the Central Plains
into the Mid-MS Valley. With no strong movement in the overall
pattern, expecting temps to remain seasonal with heat index values
around the upper 90s and 100 degree mark.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1142 PM CDT THU JUL 7 2016
VFR conditions should continue. Weak boundaries remain in the area
but cooling boundary layer should keep convection largely in
check. Should have plenty of high cloud and this will help
minimize BR development.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Drake
AVIATION...65
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1142 PM CDT THU JUL 7 2016
...Update to aviation forecast discussion...
.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 06Z TAFS through 06Z Friday Night)
Issued at 1142 PM CDT THU JUL 7 2016
VFR conditions should continue. Weak boundaries remain in the area
but cooling boundary layer should keep convection largely in
check. Should have plenty of high cloud and this will help
minimize BR development.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Prieto
AVIATION...65
Area Forecast Discussion
National Weather Service Wichita KS
658 PM CDT THU JUL 7 2016
.SHORT TERM...(This evening through Sunday night)
Issued at 313 PM CDT Thu Jul 7 2016
Low confidence forecast. Models have been struggling with
outflow/convective trends of late, and given synoptic pattern,
see little change in predictability beyond about the first period.
Some small chance for storms this afternoon/evening in southeast
KS, but based on current observations/trends, thinking cap will
hold. Current thinking is cumulus field on satellite extending from
Northwest to Southeast KS may portend the track of storms
tonight. Thinking high plains storms will eventually develop
somewhere in Northwest KS near/after sunset, then track southeast
during the night along rich moisture axis. Will trend pops that
way. This will result in extensive clouds/precipitation lingering
on Friday across forecast area, and trended temperatures down a
bit. That said, if storms do not develop overnight, chances for
strong-severe storms increases ahead of surface boundary in the
afternoon. Given uncertainty in precipitation and resultant
temperatures tomorrow, opted not to extend heat advisory at this
time. Beyond that, the entire forecast will hinge on amount/extent
of convection and location of ouflow boundaries. -Howerton
.LONG TERM...(Monday through Thursday)
Issued at 313 PM CDT Thu Jul 7 2016
Little change in extended forecast with front potentially hung up
somewhere in the forecast area by both GFS/ECMWF taken at face
value. However similar to the short term, predictibilty in timing
of shortwaves moving through mainly zonal flow and resultant mcs
is low. Clouds/precipitation will have significant impact on
temperatures as well, with some days warmer/some cooler than
initialization grids. -Howerton
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 656 PM CDT Thu Jul 7 2016
Expecting mainly VFR conditions overnight into early Fri with main
concerns being nocturnal convective chances. Still could have an
very small chance of an isolated storm along a weak outflow boundary
to the north of KCNU in ern KS, but this chance looks too small to
mention in the KCNU Taf.
Will keep an eye on convective trends to the west of the forecast
area, either in NW KS or SW KS. If convection in either location can
grow upscale overnight, this convection will drift east-southeast
overnight, potentially impacting portions of Central and South
Central KS. Not alot of confidence in either area growing upscale,
but think the better chance appears to be over South Central KS as
SW KS convection will be fed by increasing low level moisture
transport into SW KS. So will go with a VCTS for both the KGBD and
KHUT Tafs late tonight after 10z/Fri. Could see some of this shower
activity linger across South Central KS into Fri morning, so will
include a VCSH for KICT as well.
Ketcham
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 73 91 71 90 / 20 40 40 30
Hutchinson 72 89 70 89 / 30 40 40 30
Newton 72 89 70 87 / 20 40 50 40
ElDorado 73 90 71 86 / 20 40 50 40
Winfield-KWLD 74 92 72 91 / 20 40 50 40
Russell 69 89 68 91 / 40 40 50 20
Great Bend 70 89 69 91 / 40 40 40 20
Salina 72 92 71 89 / 30 30 50 30
McPherson 71 89 69 88 / 30 40 50 30
Coffeyville 75 93 72 88 / 10 40 50 50
Chanute 74 92 72 86 / 10 30 50 50
Iola 74 91 72 84 / 10 30 50 50
Parsons-KPPF 74 92 73 85 / 10 40 50 50
&&
.ICT Watches/Warnings/Advisories...
Heat Advisory until 9 PM CDT this evening for KSZ049>053-067>072-
082-083-091>096-098>100.
&&
$$
SHORT TERM...PJH
LONG TERM...PJH
AVIATION...KETCHAM
Area Forecast Discussion
National Weather Service Goodland KS
541 PM MDT THU JUL 7 2016
.UPDATE...
Issued at 530 PM MDT Thu Jul 7 2016
Cluster of strong thunderstorms currently diving south into the
cwa from the NE panhandle and moving into a more unstable and
sheared airmass. Short range CAM`s really struggling with even
next hour forecast...with the experimental HRRR being the closest.
Think storms will make a push into portions of Kansas while mean
wind continues to advect them to the east. Another area of
congested CU apparent to the southeast of KLIC which may pose
another area for potential storm development before 02z. As WAA
develops tonight redevelopment or maintenance of storms appears
likely with best chances along and south of I70.
&&
.SHORT TERM...(This evening through Friday)
Issued at 238 PM MDT Thu Jul 7 2016
High dewpoints in the upper 60s and lower 70s have pooled across the
southeast portion of the forecast area in the vicinity of a pre-
frontal trough ahead of a cold front that is approaching the region.
The national analysis shows the front already in the forecast area,
but it appears the cooler and dryer air behind the front is further
to the north across southwest Nebraska. A few storms are developing
in the vicinity of this front to the north of the forecast area this
afternoon. The possibility exists for some of these storms to move
across the far northern and northeastern portions of the forecast
area from southwest Nebraska into north central Kansas this evening
and into the overnight hours as a weak short wave trough aloft moves
across Nebraska. Have currently kept pops low enough through the
afternoon and evening to only bring a brief mention of thunderstorms
to the extreme northeast corner around 00Z.
Begin to ramp up pops after midnight over the east central portion
of the forecast area. This area will be in the vicinity of the
coldfront as it continues to push south into the forecast area
overnight and a weak short wave trough aloft moves east of the
Rockies and across western Kansas. Additional short wave activity
moves east of the Rockies and across western Kansas through the day
on Friday as the front appears to stall out over southern Kansas and
extend back into central Colorado. Southeast upslope return flow
will bring mid 60 dewpoints back into the area by late Friday with
isolated thunderstorms early in the day becoming scattered across
mainly the southeast portions of the forecast area by late in the
day on Friday.
.LONG TERM...(Friday night through Thursday)
Issued at 238 PM MDT Thu Jul 7 2016
For the extended period there will be a ridge that sits over the CWA
Friday night into Sunday afternoon. After that a trough begins to
move towards the area Sunday evening and impacts the CWA through
Tuesday; but there are some differences between the GFS and European
starting Tuesday (will see which one plays out correctly). Come late
Wednesday into Thursday the models are different in their upper
level flow, so confidence is very low which one is accurate at this
time.
Model runs have differed from yesterday in regards with keeping
Friday and Saturday similar on intensity of storm/precipitation
chances. Current model runs definitely have Friday with a stronger
storm potential and have decreased Saturday`s chances a little more
(but Saturday still could see precipitation). Friday has a shortwave
and frontal boundary that moves over the region in the late
afternoon/evening. CAPEs are around 2000-3000 J/kg, 850-500 mb lapse
rates are 7+ C/km and bulk shear is up to 50 kts. Saturday has
another shortwave but it is currently showing to move more south of
the region. So best chances for storms/precipitation will be in the
southern portions of the CWA.
Sunday will be dry during the day but the evening could see some
precipitation around 00z. This is due to the trough moving towards
the CWA, so southwest flow will bring up moisture from the southern
states and another shortwave moves through the upper level flow. As
of current model runs, the CAPE and bulk shear values are not
impressive, so this could possibly be a weak storm/precipitation
event.
Monday is the last day in the extended where the models are in fairly
good agreement. There are some differences in the broadness and exact
placement of the low pressure, but for the most part they agree. As
the trough moves north of the CWA a frontal boundary and shortwave
will sweep across the region and bring with it storm/precipitation
chances in the evening and overnight hours; primarily in the eastern
side of the CWA. CAPES are weak but bulk shear is around 40-50 kts.
Tuesday and Wednesday are the days where the models take fairly
different routes. So confidence is low on what will occur. Will
include slight PoPs each day in a few area due to the large
discrepancies between the models. The GFS keeps each day dry but the
European brings precipitation each evening. So right now it could go
either way.
Thursday, even though the models still disagree in upper level flow
both have precipitation chances in the late afternoon. Again
confidence is very low with what will actually occur.
Temperatures will be in low to mid 90s each day, with a slight
decrease Tuesday in the lower 90s as the low pressure impacts the
region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 530 PM MDT Thu Jul 7 2016
FOR 00z TAFS...Potential exists for thunderstorms to impact TAF
locations prior to 06z...but large degree of uncertainty at the
moment makes putting a prevailing or vicinity group into difficult
execept for straight interpolating current storms motion. VFR
conditions will prevail...but will monitor potential for period of
fog around sunrise at KGLD. For now...probabilities indicate this
scenario is unlikely but worth keeping an eye on.
&&
.GLD Watches/Warnings/Advisories...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...LOCKHART
LONG TERM...CLT
AVIATION...JRM
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
620 AM CDT FRI JUL 8 2016
.UPDATE...
Updated to include 12z aviation discussion.
&&
.AVIATION...
Some patchy MVFR 1500-2000ft ceilings possible around central and
southern AR terminals the next few hours, then mainly VFR
conditions expected. Winds out of the SW today 7-12kts gusting as
high as 20kts at times. Could see isolated/scattered SH/TS
activity across mainly northern areas this afternoon/evening and
then again after midnight. Widespread mid/high clouds will be in
place for much of the TAF period as well.
&&
.PREV DISCUSSION...(ISSUED 354 AM CDT FRI JUL 8 2016
)
SHORT TERM...Today Through Saturday Night
Once again, surface analysis indicates ridge of high pressure
located southeast of the state with low pressure situated over
the TX/OK panhandles. A frontal boundary stretches from the TX/OK
panhandles northeastward toward Chicago. Several series of
thunderstorm complexes can be seen on NWS radar network early this
morning, from northern Oklahoma into southern Kansas as well as
across northern Arkansas into southern Missouri.
Better rain chances will be in the forecast during the short term
period as the upper ridge across the southern US begins to retreat
westward a bit providing more of a NW flow aloft over the state.
Several upper level shortwave troughs will move along this flow
and interact with the boundary at the surface which will be
positioned across northern Arkansas the next few days. Potential
is there for remnant thunderstorm complexes to move over the state
Saturday and Sunday morning, similar to what has been seen across
Kansas and Missouri the last few days.
Even with rainfall chances in the forecast and more widespread
cloud cover noted, only northern Arkansas will see a legitimate
break from summertime heat. It will still be quite warm across
central and southern areas. Winds will be enhanced again today
with breezy conditions out of the southwest. Even lighter winds
expected Saturday.
LONG TERM...Sunday Through Thursday
A weakness in the ridge of high pressure over the southeast United
States coupled with a storm system aloft over southern Missouri
will yield isolated to scattered showers and thunderstorms in
Arkansas Sunday. At the surface, a weak stationary front will be
draped across northeast sections of the state, which is close to
the periphery of the ridge. Precipitation coverage will be
greatest north/east of Little Rock nearest the front.
A few storms may be severe. Damaging winds and hail will be the main
concerns. An organized severe weather event is not expected. 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
wobble from the Rockies to the upper Midwest. 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. As the period begins, readings may be a touch below average
toward the Missouri border near the aforementioned front.
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Aviation...226
Area Forecast Discussion
National Weather Service Little Rock AR
354 AM CDT FRI JUL 8 2016
.SHORT TERM...Today Through Saturday Night
Once again, surface analysis indicates ridge of high pressure
located southeast of the state with low pressure situated over
the TX/OK panhandles. A frontal boundary stretches from the TX/OK
panhandles northeastward toward Chicago. Several series of
thunderstorm complexes can be seen on NWS radar network early this
morning, from northern Oklahoma into southern Kansas as well as
across northern Arkansas into southern Missouri.
Better rain chances will be in the forecast during the short term
period as the upper ridge across the southern US begins to retreat
westward a bit providing more of a NW flow aloft over the state.
Several upper level shortwave troughs will move along this flow
and interact with the boundary at the surface which will be
positioned across northern Arkansas the next few days. Potential
is there for remnant thunderstorm complexes to move over the state
Saturday and Sunday morning, similar to what has been seen across
Kansas and Missouri the last few days.
Even with rainfall chances in the forecast and more widespread
cloud cover noted, only northern Arkansas will see a legitimate
break from summertime heat. It will still be quite warm across
central and southern areas. Winds will be enhanced again today
with breezy conditions out of the southwest. Even lighter winds
expected Saturday.
&&
.LONG TERM...Sunday Through Thursday
A weakness in the ridge of high pressure over the southeast United
States coupled with a storm system aloft over southern Missouri
will yield isolated to scattered showers and thunderstorms in
Arkansas Sunday. At the surface, a weak stationary front will be
draped across northeast sections of the state, which is close to
the periphery of the ridge. Precipitation coverage will be
greatest north/east of Little Rock nearest the front.
A few storms may be severe. Damaging winds and hail will be the main
concerns. An organized severe weather event is not expected. 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
wobble from the Rockies to the upper Midwest. 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. As the period begins, readings may be a touch below average
toward the Missouri border near the aforementioned front.
&&
.PRELIMINARY POINT TEMPS/POPS...
Batesville AR 93 74 87 72 / 40 30 50 60
Camden AR 97 77 96 75 / 10 20 30 30
Harrison AR 89 71 84 69 / 50 50 50 50
Hot Springs AR 95 77 92 75 / 20 30 40 30
Little Rock AR 96 78 93 76 / 20 30 40 40
Monticello AR 96 79 95 76 / 10 20 30 30
Mount Ida AR 94 75 92 73 / 20 30 40 30
Mountain Home AR 90 72 85 70 / 50 50 50 60
Newport AR 94 75 88 73 / 40 30 50 50
Pine Bluff AR 95 78 92 75 / 20 20 40 30
Russellville AR 94 76 90 74 / 20 40 50 40
Searcy AR 95 76 91 73 / 20 30 50 50
Stuttgart AR 95 77 92 75 / 20 20 40 40
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Short Term...226 / Long Term...46
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
1225 AM CDT FRI JUL 8 2016
.UPDATE...
Updated to include 06z aviation discussion.
&&
.AVIATION...
Showers and thunderstorms slowly moving SE out of SW MO and SE KS
this morning may bring vicinity SH/TS activity to northern AR
terminals this morning as they dissipate. Otherwise, MVFR
ceilings expected across central/southern AR around daybreak once
again with primarily VFR conditions seen otherwise. Winds will be
out of the SW again with speeds of 8-12kts and gusts to 20kts at
times.
&&
.PREV DISCUSSION...(ISSUED 711 PM CDT THU JUL 7 2016
)
AVIATION...08/00z Taf Cycle
Look for VFR conds to cont thru much of pd. Sct-bkn low clouds wl
again dvlp toward sunrise Fri...mainly acrs CNTRL and SRN AR...
resulting in ocnl MVFR cigs. Hi-Res model data conts to suggest a
complex of storms forming forming later tngt acrs SRN KS...
eventually working SEWD into parts of NW AR Fri mrng. Included
PROB30 groups at KHRO and KBPK to account for any storms that may
form along residual small scale bndry`s later in the day. /44/
PREV DISCUSSION...(ISSUED 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.
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Aviation...226
Area Forecast Discussion
National Weather Service Little Rock AR
711 PM CDT THU JUL 7 2016
.AVIATION...08/00z Taf Cycle
Look for VFR conds to cont thru much of pd. Sct-bkn low clouds wl
again dvlp toward sunrise Fri...mainly acrs CNTRL and SRN AR...
resulting in ocnl MVFR cigs. Hi-Res model data conts to suggest a
complex of storms forming forming later tngt acrs SRN KS...
eventually working SEWD into parts of NW AR Fri mrng. Included
PROB30 groups at KHRO and KBPK to account for any storms that may
form along residual small scale bndry`s later in the day. /44/
&&
.PREV DISCUSSION...(ISSUED 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.
&&
.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.
&&
$$
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 San Diego CA
901 AM PDT FRI JUL 8 2016
.SYNOPSIS...
Fair and seasonal weather will continue this coming week as a
persistent summertime pattern continues. Expect lots of sunshine
along with coastal clouds nights and mornings. A low pressure trough
will bring slightly cooler weather along with some gusty winds in
parts of the mountains and deserts on Sunday and Monday. A high
pressure ridge will bring warmer weather Tuesday through Thursday
and less extensive coastal clouds.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Low clouds were overall slightly less extensive at sunrise this
morning than they were yesterday at that time. The marine layer
depth was about the same while the cloud bases were a little
higher. The result was a thinner cloud deck that cleared quickly
this morning. Very similar weather will continue this coming week,
but with some slight variations. A high pressure ridge over Texas
will morph westward today and Saturday, which will suppress the
marine layer and boost temperatures just a little. On Sunday a low
pressure trough will move through the northwestern states. For us
it will bring a coastal eddy that will deepen our marine layer
and extend the coastal clouds farther inland Sunday and Monday.
It will also bring some gusty westerly winds in parts of the
mountains and deserts, particularly Sunday evening. Temperatures
will drop a few degrees across the region those days. On Tuesday
the high pressure ridge reasserts itself to start a warming trend.
Higher daytime temperatures will result Tuesday through Thursday.
&&
.AVIATION...
081530Z...Coast/Valleys...Stratus, with bases 1600-2000 ft MSL and
tops near 2500 ft MSL, will clear over the valleys and coast by 17Z
this morning. The marine layer inversion was around 9 C this
morning. Far inland areas with vis of 3-5 SM HZ will improve to P6SM
by 18Z. VFR conditions will prevail this afternoon, with low clouds
redeveloping along the coast late this evening, with slightly lower
tops and bases. Vis of 2-4 SM BR is expected over inland areas where
low clouds near higher terrain.
Mountains/Deserts...Clear with unrestricted vis through Saturday
morning. Local West wind 25-35KT through and below the passes in
Riverside and San Diego counties, with associated uddfs/llws this
afternoon and evening.
&&
.MARINE...
830 am...Westerly wind gusts near 20 kt will develop over the outer
waters Sunday as an upper-level low pressure trough approaches the
region. Otherwise, no hazardous marine weather is expected through
Monday.
&&
.BEACHES...
830 am...South swells from 190-210 degrees will peak 4 ft/12 seconds
today and Saturday. This will generate surf of 3 to 5 ft and
moderate to strong rip currents along south and southwest facing
beaches through the weekend. Highest surf and greatest area of
strong rip currents will be in northern Orange county. A Beach
Hazard Statement is in effect through Sunday evening for Orange
County.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX Watches/Warnings/Advisories...
CA...Beach Hazards Statement through Sunday evening for Orange County
Coastal Areas.
PZ...None.
&&
$$
PUBLIC...MM
AVIATION/MARINE/BEACHES...JJT
[top]
Area Forecast Discussion
National Weather Service Phoenix AZ
840 AM MST FRI JUL 8 2016
&&
.SYNOPSIS...
A dry and stable airmass will remain across much of the desert
southwest through next week. Afternoon temperatures on the lower
deserts will be a few degrees above normal, or in the 107 to 110
degree range.
&&
.DISCUSSION...
An extremely quiet morning (for early July) today as our typical
monsoon moisture has been pushed off well to the south and east of
our cwa. An indication of how dry the atmosphere is can be seen in
the morning dewpoints across South-Central AZ, which are now mainly
in the upper 30s and 40s, and in the 12Z PSR balloon sounding, which
shows a PWAT of only 0.69 inch. The more typical 50 and 60 degree
dewpoints have been pushed southward into the Tucson area and across
extreme se AZ. Given the continued forecast for more westerly flow
through the column across the region, and the latest HRRR high-res
model run, which continues to keep all afternoon/evening convection
well off to our south and east, the current forecast for near-zero
pops across most of our cwa looks good, and no updates are planed at
this time.
&&
.PREVIOUS DISCUSSION...
Today through Friday...
Thursday evenings weather balloon soundings over AZ continued to
detect remnant monsoon moisture mainly over the southeast quarter
of the state. However PHX and TUS VAD wind profiles at 2 am mst
showed low level west and northwest winds, indicative of drier air
spreading in from the west. Yet despite remnant monsoon moisture
yesterday, atmospheric mid levels were still too warm for any
convective threats in our forecast area near Phoenix.
Models however do forecast bouts of moisture seeps from Mexico, from
occasional low level south winds, but mainly into far southeast AZ
and outside our forecast area through the weekend. Besides, mid
level temperatures stay fairly warm, providing a very stable
afternoon airmass through next week. In fact the GFS model forecasts
500 mb temps to warm to minus 2 deg C over southern CA and southern
AZ on Monday. This is rare and has happened about 2 or 3 times in 30
years. In fact a quick look at modeled 500 mb temperatures across
the entire Pacific to Asia, even in the equatorial regions, show the
minus 2 deg C in AZ to be warmest, with the exception of a modeled
plus 6 deg C temp over Himalaya Mtns. Mt Everest at 29 K ft is 11K
ft above the 500 mb level.
Therefore dry and stable conditions are forecast the next seven
days, with an extended break in the Monsoon.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA and KSDL:
Generally clear skies to continue with some afternoon high based cu
mainly situated over the high terrain to the east. Winds will follow
typical diurnal patterns with occasionally gusty afternoon westerlies.
Southeast California/Southwest Arizona including KIPL and KBLH:
Southerly winds through the afternoon with winds shifting westerly at
KIPL this evening. Winds will be breezy at KBLH this afternoon, but
gusts should mostly remain less than 20 kts. Skies to remain clear.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Sunday through Thursday...
Unusually dry conditions to settle over the area throughout the
weekend lasting through much of next week. With temperatures
hovering near a warm seasonal average, minimum afternoon humidity
levels will fall to around 10% over lower elevations, and 15-20% in
higher terrain. Overnight recovery will only be fair. Occasionally
breezy southwest afternoon winds will affect the region, however
speeds will remain well below any critical thresholds. Overall,
weather conditions will mirror a typical early/mid June versus mid
July.
&&
.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...Percha/Vasquez
AVIATION...Kuhlman
FIRE WEATHER...Kuhlman
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
428 AM PDT FRI JUL 8 2016
.SYNOPSIS...An unseasonably cool upper-level trough will bring
significantly cooler temperatures and a chance of rain through the
weekend. Tempertures will moderate across the interior for the by
the middle of next week.
&&
.DISCUSSION...
.SHORT TERM...
(Today through Sunday)
Cooler and wetter conditions will return to most of the region
during the next few days. An unseasonably strong upper-level trough
is currently moving into the area. Several disturbances in the flow
aloft will cross northern California over the next few days,
bringing rounds of increasing ascent, which will aid in the coverage
and intensity of any rainfall. The more favored locations for this
will be across the northern half of the forecast area, as this
region will reside under the jet stream aloft, which these
disturbances will traverse in. Heading through the weekend,
additional disturbances will continue to cross the area, as the
trough digs farther south, lowering the mid-level heights while
prolonging the rainfall potential through Sunday.
Taking a closer look at the various model initializations/forecasts,
they show precipital water values (PWATs) at 06z ranging from 0.5 to
0.75 inches across the Trinity horn, to ~0.75-1 inch along the
Redwood coast, with a plume of >1.5 inches pointed towards the
Oregon coast. This plume is forecast to drop south and have these
PWATs increase from ~1 inch across Trinity county to the 1.4 to 1.6
inch range along and west of Highway 101 across Humboldt, and Del
Norte counties by 15z, reaching the Mendocino coast after 00z. In
fact, looking at current values to our north and cross-referencing
with the SPC climatology page, the current values at Medford and
Salem, Oregon are in the 90th to 95th percentile range.
Given the very good model continuity and considering the various
factors mentioned above, POPs were increased for most of the
forecast area through Sunday. As mentioned in the forecast
discussion from yesterday, rainfall records for today of 0.22 inches
at Eureka and 0.62 inches at Crescent City could be in jeopardy of
being tied or broken. With decreasing heights aloft, persistent
cloud cover, and periods of rain, afternoon high temperatures will
be cooler than average across the interior through the weekend, with
coastal locations remaining near seasonal normals.
.LONG TERM...
(Monday through Thursday)
A zonal flow will return to the region, with rising mid-level
heights and temperatures at 850mb warming compared to this weekend.
Northerly surface winds are expected to develop by Monday and
persist through at least the middle of the week. This type of setup
will allow temperatures to warm significantly across the interior
valleys, while remaining close to normal near the coast. /PD
&&
.AVIATION...A frontal band of cloudiness will continue to
impact the Redwood Coast terminals this morning. Generally light
rain will continue to shift SE, eventually spreading to KACV. The
models disagree with the timing of this precipitation with the WRF
bringing it to KACV by 14-15Z and the HRRR holding off until 00Z.
The latest radar trends argue for an earlier timing, but much of
this will likely be drizzle. However, deep layer moisture and
orographic forcing should allow for periods of light rain as well.
Rainfall should decrease in coverage and intensity by afternoon with
a resurgence of light rain Friday night as the upper trough gets
closer to the area. Generally VFR conditions are expected at KUKI
until evening when low clouds are forecast to move into the area.
Area-wide, winds are expected to remain fairly light. /SEC
&&
.MARINE...Light winds are forecast to continue through the weekend
with wind directions occasionally becoming southerly N of Cape
Mendocino ahead of a few frontal troughs. N winds are expected to
return by Sunday night with advisory level speeds possible in the
southern offshore waters. More widespread northerlies are progged by
the middle of the coming week as high pressure over the E Pacific
rebuilds toward the area and the inland thermal trough sharpens.
/SEC
&&
.EKA Watches/Warnings/Advisories...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...None.
&&
$$
Visit us at http://WWW.WEATHER.GOV/EUREKA
Follow us on facebook and twitter at:
http://www.facebook.com/NWSEureka
http://www.twitter.com/nwseureka
FOR FORECAST ZONE INFORMATION
SEE FORECAST ZONE MAP ONLINE:
http://www.weather.gov/eureka/zonemap.png
AREA FORECAST DISCUSSION
NWS MIAMI FL
ISSUED BY NATIONAL WEATHER SERVICE KEY WEST FL
1007 AM EDT FRI JUL 8 2016
.UPDATE...
MORNING SOUNDING REMAINED LOW WITH PRECIPITABLE WATER JUST ABOVE
1.2 INCHES...SOLID DRYNESS ABOVE 960 MB. LIGHT EAST TO SOUTHEAST
WINDS WERE NOTED OFF THE DECK WITH VERY LITTLE IF ANY STEERING
ALOFT. FORECAST TEMPERATURES REMAINS ON TARGET WITH NEAR 90
COAST AND MID 90S INTERIOR, AND HEAT INDICES 103 TO 107 AWAY FROM
THE COAST. ISOLATED TO SCATTERED CONVECTION WITH MID TO LATE
AFTERNOON ONSET STILL APPEARS ON TAP FOR MAINLY INLAND PORTIONS
AND BEST INITIATED NEAR SEABREEZE AND LAKE BOUNDARIES.
&&
.PREV DISCUSSION... /ISSUED 756 AM EDT FRI JUL 8 2016/
AVIATION...
VFR IS GENERALLY EXPECTED BUT THE HIGH RESOLUTION GUIDANCE IS
STARTING TO HINT AT SOME CONVECTION BEING POSSIBLE INLAND
CONVECTION THIS AFTERNOON. THERE MIGHT BE AN IMPACT TO THE
TERMINALS WITH ANY CONVECTION REMAINING AS THE SEA BREEZES
RETREAT. OVERNIGHT, CONVECTION SHOULD DIMINISH AND WINDS SHOULD
BECOME LIGHTER.
02/RAG
.DISCUSSION...
STRONG UPPER LEVEL RIDGE IN PLACE WILL CONTINUE TO DOMINATE THE
WEATHER PATTERN FOR TODAY AND SATURDAY WITH RELATIVELY DRIER AIR
IN PLACE. THIS WILL LIMIT SHOWER ACTIVITY IN THE AFTERNOON/EVENING
HRS THROUGH SATURDAY. A FEW SHOWERS MAY STILL DEVELOP MAINLY IN
THE INTERIOR AND WEST. UPPER LEVEL RIDGE BEGINS TO WEAKEN AS
SHORT WAVE TROUGH ENTERS THE NORTHEAST ATLANTIC COAST FRIDAY INTO
SATURDAY. FORECAST SOUNDING INDICATE A SLIGHT INCREASES ON THE
PWAT`S TO AROUND 1.6 IN BUT MOISTURE CONTENT IN THE MID LEVELS IS
STILL VERY LIMITED. THIS WILL LIMIT THE POTENTIAL FOR SUSTAIN
AFTERNOON CONVECTION. THERE IS STILL A CHANCE OF SOME SHOWERS
DEVELOPING IN THE INTERIOR AND WEST. HIGH TEMPERATURES WILL STILL
BE IN THE 90S ALONG THE ATLANTIC AND GULF COAST AND MID TO UPPER
90S IN THE INTERIOR. HEAT INDEX VALUES ARE FORECAST TO BE AROUND
101 TO 104 ALONG THE ATLANTIC COAST AND 104 TO 107 IN THE
INTERIOR AND WEST GULF COAST.
THE WEATHER PATTERN WILL NOT VARY MUCH BY THE END OF THE WEEKEND
AND INTO THE NEXT WEEK AS SHORTWAVE LIFTS NORTHEAST WITH RIDGE
BUILDING OVER THE REGION ONCE AGAIN. THE LACK OF MOISTURE IN THE
MID LEVELS WILL STILL LIMIT THE POTENTIAL FOR TYPICAL SUMMER
AFTERNOON/EVENING CONVECTION. HOWEVER, A FEW ISOLATED SHOWERS CAN
NOT BE RULED OUT IN THE INTERIOR AND WEST BY THE LATE AFTERNOON
HOUR THROUGH THE WEEK. HIGH TEMPERATURES RETURN TO NEAR SEASONAL
NORMAL WITH HEAT INDEX AROUND 101 TO 105THROUGH MID WEEK.
&&
.MARINE...
AS HIGH PRESSURE REMAINS IN CONTROL OVER THE ATLANTIC WATERS, A
LIGHT TO MODERATE SOUTHEAST FLOW PREVAILS THROUGH MUCH OF THE
PERIOD OVER THE ATLANTIC WATERS. WEAK GRADIENT ALONG THE COAST AND
LIGHT SOUTHEAST FLOW WILL KEEP SEAS AROUND 2 FEET OR LESS THROUGH
THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 93 80 92 79 / 10 0 10 20
FORT LAUDERDALE 92 81 92 81 / 10 10 10 20
MIAMI 93 80 93 80 / 20 10 10 20
NAPLES 92 78 92 77 / 20 10 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AVIATION...02/RAG/35/JR
SHORT TERM...35/JR
[top]
Area Forecast Discussion
National Weather Service Melbourne FL
940 AM EDT FRI JUL 8 2016
.DISCUSSION...
...Continued Hot and Humid with Isolated to Scattered Late Afternoon
Storms...
.UPDATE...The central Florida peninsula is between two upper lows
this morning one well west across the central Gulf of Mexico and
another about 350 miles east of Grand Bahama Island. At the mid
levels...a weak H5 ridge center was off the SW FL coast with a 500
mb trough dropping se off the SE Atlc coast through the day and
bringing increasing mid layer northerly flow behind this feature
toward evening. The sfc ridge extends across S FL into the ern Gulf
with low lvl SW flow veering some to the NW-W across the north
through the day. Morning soundings show PWATs around 1.6-1.7 inches
from Tampa to the Cape with warm mid level temps at H7 around 11
degs C. H5 temps have cooled to -8 to -9 C though which may portend
some stronger late day convection with mid level vort dropping down
from the nrn peninsula twd early evening. Higher resolution short
range models indicate some increase in convection from yesterday
though HRRR again looks over done on coverage. NSSL WRF and 4km WRF
for SPC has somewhat later convective development than local WRFs
and recent HRRR runs with convection favored across areas from the
srn interior up to Orlando and Volusia/nrn Brevard into the evening.
Made some slight adjustments to temps in a few spots and increased
pops to 30 pct for srn interior areas south of a subtle sfc trough
feature and where best late day convergence may occur south of this
boundary. Overall though another hot and humid day with highs from
92-95 across the coastal counties and 94-98 across the interior.
Heat indices will peak from 103 to 107 degrees for much of the area.
&&
.AVIATION...
Mainly VFR through 18z then continue VCTS for KDAB and interior
terminals this afternoon. Will consider need for any TEMPO groups
with convective trends into this afternoon but coverage expected to
be isolated, with slightly higher coverage possible across the
interior from KMCO southward.
&&
.MARINE...
SSW/SW winds across the waters this morning will become SE near the
coast this afternoon to 10-15 knots. seas 2 ft near shore to 3 ft
well offshore. Little change to forecast with CWF update.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 95 76 94 76 / 20 20 20 10
MCO 96 76 95 76 / 20 20 20 10
MLB 94 77 92 76 / 10 10 20 10
VRB 94 75 92 75 / 10 10 10 10
LEE 97 77 96 77 / 20 20 20 10
SFB 98 77 96 77 / 20 20 20 10
ORL 97 78 95 78 / 20 20 20 10
FPR 93 73 92 75 / 10 10 10 10
&&
.MLB Watches/Warnings/Advisories...
FL...None.
AM...None.
&&
$$
Volkmer/Bragaw
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
623 AM CDT FRI JUL 8 2016
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 326 AM CDT FRI JUL 8 2016
An amplified upper level trough across the upper midwest early this
morning will move east across the eastern Great Lakes Tonight. The
upper flow across eastern KS will weaken and shift to the northwest
through Tonight as an upper level ridge amplifies across the high
plains.
At the surface a weak cold front front extended from northwest MO,
southwest through Topeka, then west southwest across western KS. An
out flow boundary extended from northwest OK, northeast into south
central KS, then extended east across southeast KS. North of the
boundary a few showers and thunderstorms continued to develop across
southeast KS early this morning. A complex of storms that developed
across the northern TX PNHDL has amplified an MCV across southwest
KS.
Most models show the weak front becoming stationary south of the CWA
through the mid morning hours with frontolysis occurring through the
afternoon hours across western KS. The NAM and GFS models show the
MCV over southwest KS shifting east across the southern counties of
the CWA through the late morning and afternoon hours which may
provide enough ascent for showers and thunderstorms to develop. If
these solution are accurate, then there will be chances for showers
and thunderstorms south of I-70, beginning across the southwest
counties during the late morning hours and expanding east across the
southern half of the CWA during the early and mid afternoon hours.
The mesocale models, such as the HRRR, WRF and RAP show the MCV
weakening and no precip developing through the day.
Highs today will reach the upper 80s to lower 90s with heat indices
in the mid to upper 90s
Tonight, all the numerical models show that any complex of storms
that develop across eastern CO during the evening hours will track
southeast across southwest KS into northern OK. There could be
enough isentropic lift after mid night on the northern and eastern
edge of the deeper moisture return across central and western KS for
scattered elevate thunderstorms to develop across the southwest and
southern counties of the CWA.
.LONG TERM...(Saturday through Thursday)
Issued at 326 AM CDT FRI JUL 8 2016
The weekend will see slight chance POPs over the area to begin
with. Weak isentropic lift sets up in the morning over northeastern
Kansas on Saturday as weak shortwaves pass overhead into the day.
Forcing is weak overall, so much of this could just result in
enhanced cloud cover rather than any widespread showers and isolated
thunderstorms. There will still be plenty of instability with
dewpoints still forecast to be in the upper 60s and low 70s. As a
North Pac Low deepens and digs into the Pacific Northwest, mid to
upper level ridging will amplify over the Central and Northern
Plains into Sunday and should see mainly dry conditions set up over
the region with good mixing into the afternoon. Therefore,
expecting temps to rise into the low and possibly mid 90s. This
will bring heat index values up to around or into the low 100s. Not
anticipating headlines at this time for an advisory though. It may
be something to watch if we can hold off more cloud cover and temps
rise a bit more.
Monday into the Monday night time frame, the North Pac Low will
deepen and take on a negative tilt as it lifts into the Northern
Plains. A modified cold boundary will move into the Central Plains
and stall out as this system lifts into Central Canada. Greatest
chance POPs will likely be overnight Monday as the best shear zone
advects overhead with the mean trough. At least this appears to be
the best chance for any organized storms to form. A strong EML will
have also set up over the Central Plains, so it may be too capped
for development to take place, but mainly elevated storms look like
the best possibility which if they form could create some strong
gusty winds and hail. Still difficult to eliminate precip chances
out of subsequent periods as quasi-zonal flow regime sets up and
weak impulses traverse overhead. Still looks like possibility
remains for off and on showers and storms into the Friday time frame
with a stationary boundary likely lingering over the Central Plains
into the Mid-MS Valley. With no strong movement in the overall
pattern, expecting temps to remain seasonal with heat index values
around the upper 90s and 100 degree mark.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
Issued at 622 AM CDT FRI JUL 8 2016
VFR conditions are forecast through the period. Storms this morning
will stay south of the terminals. There is a possibility for
convection overnight, but for now the best chances stay south of the
terminals.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Drake
AVIATION...Heller
Area Forecast Discussion
National Weather Service Little Rock AR
305 PM CDT FRI JUL 8 2016
.SHORT TERM...Tonight through Saturday Night
Sctd SHRA/TSRA have rapidly formed acrs parts of N-CNTRL and NERN AR
this aftn...assocd with MCV that worked into NW AR earlier in the
day. Severe t-storm watch in effect for those areas until 9 pm tngt.
Have adjusted POPS accordingly to reflect current trends...with
dcrsg coverage expected later this evening as the upr energy shifts
away fm the FA.
Upr rdg is fcst to contract ovr the FA heading into weekend...
allowing a series of upr impulses to move SEWD acrs AR. This wl
result in several more convective complexes to form upstream and
eventually affect the region. Timing and coverage of each sys wl be
the main fcst concern. Still expect to see the best chcs acrs the
NERN half of the FA thru Sat ngt. Rainfall amts upwards of an inch
or two can be expected ovr NRN AR...with lesser chcs the further S
you go. Rain and clouds wl hold down high temps ovr NRN and parts of
CNTRL AR...with the warmest readings in the SRN part of the CWA.
&&
.Long Term...Sunday Through Friday
The extended forecast will start with rain in the forecast with the
nearly stalled frontal boundary over AR. The best chances will be
over central and northern AR on Sunday, then as the boundary is
expected to lift northward on Monday, a lower chance and more in the
east to northeast will be seen. On Tuesday and much of the rest of
the week, a more isolated afternoon to evening chance of convection
will be seen during the heat of the day...as the upper high pressure
ridge builds more into the Plains and caps some of the potential.
The overall chance of strong to severe storms will be low and
isolated. Otherwise...Temperatures will generally run above normal
values...as humidity levels remain high. Heat index values will also
remain in the 90s to 100 degrees to around 105 most days.
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Short Term...44 / Long Term...59
Area Forecast Discussion
National Weather Service Little Rock AR
112 PM CDT FRI JUL 8 2016
.AVIATION...08/18Z Taf Cycle
Remnants from morning MCS now affecting parts of NWRN AR. Expect
additional sctd SHRA/TSRA to form this aftn acrs NRN and WRN AR
along assocd outflow bndry/s. Have TEMPO groups at KHRO and KBPK
this aftn to account for this. Outside of convection...VFR conds
wl prevail thru the pd. Cannot rule out some SCTD low clouds again
Sat mrng...but moisture lvls not as abundant to mention any CIGS
attm. /44/
&&
.PREV DISCUSSION...(ISSUED 1139 AM CDT FRI JUL 8 2016)
UPDATE...
Cont to monitor convective trends to our NW this mrng. MCS conts
to work EWD this aftn and affect mainly the NRN third of the FA.
While an overall weakening trend has been noted...expect storms to
refire as we apch max aftn heating. Some sctd SHRA/TSRA has
formed in the last hour over parts of W-CNTRL AR in the vcnty of
the an assocd outflow bndry and along the SERN periphery of the
higher lvl cloud shield.
Just made some minor adjustments to POPS this aftn to account for
radar/Hi-Res model trends. As expected...high temps ovr N AR wl be
held down some by abundant clouds/rain chcs. Cannot rule out a few
strong/svr storms this aftn as well...with gusty winds being the
main concern. Rest of fcst in good shape. All updates are out.
/44/
PREV DISCUSSION...(ISSUED 354 AM CDT FRI JUL 8 2016)
SHORT TERM...Today Through Saturday Night
Once again, surface analysis indicates ridge of high pressure
located southeast of the state with low pressure situated over
the TX/OK panhandles. A frontal boundary stretches from the TX/OK
panhandles northeastward toward Chicago. Several series of
thunderstorm complexes can be seen on NWS radar network early this
morning, from northern Oklahoma into southern Kansas as well as
across northern Arkansas into southern Missouri.
Better rain chances will be in the forecast during the short term
period as the upper ridge across the southern US begins to retreat
westward a bit providing more of a NW flow aloft over the state.
Several upper level shortwave troughs will move along this flow
and interact with the boundary at the surface which will be
positioned across northern Arkansas the next few days. Potential
is there for remnant thunderstorm complexes to move over the state
Saturday and Sunday morning, similar to what has been seen across
Kansas and Missouri the last few days.
Even with rainfall chances in the forecast and more widespread
cloud cover noted, only northern Arkansas will see a legitimate
break from summertime heat. It will still be quite warm across
central and southern areas. Winds will be enhanced again today
with breezy conditions out of the southwest. Even lighter winds
expected Saturday.
LONG TERM...Sunday Through Thursday
A weakness in the ridge of high pressure over the southeast United
States coupled with a storm system aloft over southern Missouri
will yield isolated to scattered showers and thunderstorms in
Arkansas Sunday. At the surface, a weak stationary front will be
draped across northeast sections of the state, which is close to
the periphery of the ridge. Precipitation coverage will be
greatest north/east of Little Rock nearest the front.
A few storms may be severe. Damaging winds and hail will be the main
concerns. An organized severe weather event is not expected. 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
wobble from the Rockies to the upper Midwest. 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. As the period begins, readings may be a touch below average
toward the Missouri border near the aforementioned front.
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
1139 AM CDT FRI JUL 8 2016
.UPDATE...
Cont to monitor convective trends to our NW this mrng. MCS conts
to work EWD this aftn and affect mainly the NRN third of the FA.
While an overall weakening trend has been noted...expect storms to
refire as we apch max aftn heating. Some sctd SHRA/TSRA has
formed in the last hour over parts of W-CNTRL AR in the vcnty of
the an assocd outflow bndry and along the SERN periphery of the
higher lvl cloud shield.
Just made some minor adjustments to POPS this aftn to account for
radar/Hi-Res model trends. As expected...high temps ovr N AR wl be
held down some by abundant clouds/rain chcs. Cannot rule out a few
strong/svr storms this aftn as well...with gusty winds being the
main concern. Rest of fcst in good shape. All updates are out.
/44/
&&
.PREV DISCUSSION...(ISSUED 354 AM CDT FRI JUL 8 2016)
SHORT TERM...Today Through Saturday Night
Once again, surface analysis indicates ridge of high pressure
located southeast of the state with low pressure situated over
the TX/OK panhandles. A frontal boundary stretches from the TX/OK
panhandles northeastward toward Chicago. Several series of
thunderstorm complexes can be seen on NWS radar network early this
morning, from northern Oklahoma into southern Kansas as well as
across northern Arkansas into southern Missouri.
Better rain chances will be in the forecast during the short term
period as the upper ridge across the southern US begins to retreat
westward a bit providing more of a NW flow aloft over the state.
Several upper level shortwave troughs will move along this flow
and interact with the boundary at the surface which will be
positioned across northern Arkansas the next few days. Potential
is there for remnant thunderstorm complexes to move over the state
Saturday and Sunday morning, similar to what has been seen across
Kansas and Missouri the last few days.
Even with rainfall chances in the forecast and more widespread
cloud cover noted, only northern Arkansas will see a legitimate
break from summertime heat. It will still be quite warm across
central and southern areas. Winds will be enhanced again today
with breezy conditions out of the southwest. Even lighter winds
expected Saturday.
LONG TERM...Sunday Through Thursday
A weakness in the ridge of high pressure over the southeast United
States coupled with a storm system aloft over southern Missouri
will yield isolated to scattered showers and thunderstorms in
Arkansas Sunday. At the surface, a weak stationary front will be
draped across northeast sections of the state, which is close to
the periphery of the ridge. Precipitation coverage will be
greatest north/east of Little Rock nearest the front.
A few storms may be severe. Damaging winds and hail will be the main
concerns. An organized severe weather event is not expected. 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
wobble from the Rockies to the upper Midwest. 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. As the period begins, readings may be a touch below average
toward the Missouri border near the aforementioned front.
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
620 AM CDT FRI JUL 8 2016
.UPDATE...
Updated to include 12z aviation discussion.
&&
.AVIATION...
Some patchy MVFR 1500-2000ft ceilings possible around central and
southern AR terminals the next few hours, then mainly VFR
conditions expected. Winds out of the SW today 7-12kts gusting as
high as 20kts at times. Could see isolated/scattered SH/TS
activity across mainly northern areas this afternoon/evening and
then again after midnight. Widespread mid/high clouds will be in
place for much of the TAF period as well.
&&
.PREV DISCUSSION...(ISSUED 354 AM CDT FRI JUL 8 2016
)
SHORT TERM...Today Through Saturday Night
Once again, surface analysis indicates ridge of high pressure
located southeast of the state with low pressure situated over
the TX/OK panhandles. A frontal boundary stretches from the TX/OK
panhandles northeastward toward Chicago. Several series of
thunderstorm complexes can be seen on NWS radar network early this
morning, from northern Oklahoma into southern Kansas as well as
across northern Arkansas into southern Missouri.
Better rain chances will be in the forecast during the short term
period as the upper ridge across the southern US begins to retreat
westward a bit providing more of a NW flow aloft over the state.
Several upper level shortwave troughs will move along this flow
and interact with the boundary at the surface which will be
positioned across northern Arkansas the next few days. Potential
is there for remnant thunderstorm complexes to move over the state
Saturday and Sunday morning, similar to what has been seen across
Kansas and Missouri the last few days.
Even with rainfall chances in the forecast and more widespread
cloud cover noted, only northern Arkansas will see a legitimate
break from summertime heat. It will still be quite warm across
central and southern areas. Winds will be enhanced again today
with breezy conditions out of the southwest. Even lighter winds
expected Saturday.
LONG TERM...Sunday Through Thursday
A weakness in the ridge of high pressure over the southeast United
States coupled with a storm system aloft over southern Missouri
will yield isolated to scattered showers and thunderstorms in
Arkansas Sunday. At the surface, a weak stationary front will be
draped across northeast sections of the state, which is close to
the periphery of the ridge. Precipitation coverage will be
greatest north/east of Little Rock nearest the front.
A few storms may be severe. Damaging winds and hail will be the main
concerns. An organized severe weather event is not expected. 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
wobble from the Rockies to the upper Midwest. 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. As the period begins, readings may be a touch below average
toward the Missouri border near the aforementioned front.
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Aviation...226
Area Forecast Discussion
National Weather Service Little Rock AR
354 AM CDT FRI JUL 8 2016
.SHORT TERM...Today Through Saturday Night
Once again, surface analysis indicates ridge of high pressure
located southeast of the state with low pressure situated over
the TX/OK panhandles. A frontal boundary stretches from the TX/OK
panhandles northeastward toward Chicago. Several series of
thunderstorm complexes can be seen on NWS radar network early this
morning, from northern Oklahoma into southern Kansas as well as
across northern Arkansas into southern Missouri.
Better rain chances will be in the forecast during the short term
period as the upper ridge across the southern US begins to retreat
westward a bit providing more of a NW flow aloft over the state.
Several upper level shortwave troughs will move along this flow
and interact with the boundary at the surface which will be
positioned across northern Arkansas the next few days. Potential
is there for remnant thunderstorm complexes to move over the state
Saturday and Sunday morning, similar to what has been seen across
Kansas and Missouri the last few days.
Even with rainfall chances in the forecast and more widespread
cloud cover noted, only northern Arkansas will see a legitimate
break from summertime heat. It will still be quite warm across
central and southern areas. Winds will be enhanced again today
with breezy conditions out of the southwest. Even lighter winds
expected Saturday.
&&
.LONG TERM...Sunday Through Thursday
A weakness in the ridge of high pressure over the southeast United
States coupled with a storm system aloft over southern Missouri
will yield isolated to scattered showers and thunderstorms in
Arkansas Sunday. At the surface, a weak stationary front will be
draped across northeast sections of the state, which is close to
the periphery of the ridge. Precipitation coverage will be
greatest north/east of Little Rock nearest the front.
A few storms may be severe. Damaging winds and hail will be the main
concerns. An organized severe weather event is not expected. 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
wobble from the Rockies to the upper Midwest. 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. As the period begins, readings may be a touch below average
toward the Missouri border near the aforementioned front.
&&
.PRELIMINARY POINT TEMPS/POPS...
Batesville AR 93 74 87 72 / 40 30 50 60
Camden AR 97 77 96 75 / 10 20 30 30
Harrison AR 89 71 84 69 / 50 50 50 50
Hot Springs AR 95 77 92 75 / 20 30 40 30
Little Rock AR 96 78 93 76 / 20 30 40 40
Monticello AR 96 79 95 76 / 10 20 30 30
Mount Ida AR 94 75 92 73 / 20 30 40 30
Mountain Home AR 90 72 85 70 / 50 50 50 60
Newport AR 94 75 88 73 / 40 30 50 50
Pine Bluff AR 95 78 92 75 / 20 20 40 30
Russellville AR 94 76 90 74 / 20 40 50 40
Searcy AR 95 76 91 73 / 20 30 50 50
Stuttgart AR 95 77 92 75 / 20 20 40 40
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Short Term...226 / Long Term...46
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
1225 AM CDT FRI JUL 8 2016
.UPDATE...
Updated to include 06z aviation discussion.
&&
.AVIATION...
Showers and thunderstorms slowly moving SE out of SW MO and SE KS
this morning may bring vicinity SH/TS activity to northern AR
terminals this morning as they dissipate. Otherwise, MVFR
ceilings expected across central/southern AR around daybreak once
again with primarily VFR conditions seen otherwise. Winds will be
out of the SW again with speeds of 8-12kts and gusts to 20kts at
times.
&&
.PREV DISCUSSION...(ISSUED 711 PM CDT THU JUL 7 2016
)
AVIATION...08/00z Taf Cycle
Look for VFR conds to cont thru much of pd. Sct-bkn low clouds wl
again dvlp toward sunrise Fri...mainly acrs CNTRL and SRN AR...
resulting in ocnl MVFR cigs. Hi-Res model data conts to suggest a
complex of storms forming forming later tngt acrs SRN KS...
eventually working SEWD into parts of NW AR Fri mrng. Included
PROB30 groups at KHRO and KBPK to account for any storms that may
form along residual small scale bndry`s later in the day. /44/
PREV DISCUSSION...(ISSUED 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.
&&
.LZK Watches/Warnings/Advisories...NONE.
&&
$$
Aviation...226
Area Forecast Discussion
National Weather Service Little Rock AR
711 PM CDT THU JUL 7 2016
.AVIATION...08/00z Taf Cycle
Look for VFR conds to cont thru much of pd. Sct-bkn low clouds wl
again dvlp toward sunrise Fri...mainly acrs CNTRL and SRN AR...
resulting in ocnl MVFR cigs. Hi-Res model data conts to suggest a
complex of storms forming forming later tngt acrs SRN KS...
eventually working SEWD into parts of NW AR Fri mrng. Included
PROB30 groups at KHRO and KBPK to account for any storms that may
form along residual small scale bndry`s later in the day. /44/
&&
.PREV DISCUSSION...(ISSUED 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.
&&
.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.
&&
$$
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
NWS LOS ANGELES/OXNARD CA
324 PM PDT FRI JUL 8 2016
...Updated to include fire weather discussion...
.SYNOPSIS...
The onshore flow over the coast and some valleys will bring an
overnight marine layer into next week...that should clear by the
afternoons. Breezy winds may occur in the mountains and deserts into
Monday. The near normal afternoon temperatures will persist through
Monday...with overnight lows above normal. A high should build in
from Tuesday to Thursday for a slow warming trend. Then a low system
may approach by the weekend.
&&
.SHORT TERM...(TDY-MON)
A low pressure system currently just west of Vancouver will drop
into Oregon tomorrow with a dry trough extending into central
California...then move eastward through Monday. Northwest winds
will strengthen Saturday night through Sunday night as a result.
Southern Santa Barbara County will likely need a wind advisory
Saturday night through Sunday night...while the LA Mountains and
the Antelope Valley should need one for late Sunday afternoon and
night. Gusts into the 50 mph range are likely in these areas
during the wind peak Sunday night. Monday will also see some
breezy northwest winds...but should be the weakest of the next
three days.
Stratus coverage and temperatures on Saturday should be similar
to today...save for less stratus over SBA and SLO counties thanks
to the dry front passage and the SMX-BFL pressure gradient
significantly weakening by 3 mb. The Northwest flow will likely
keep most of Ventura and southern SBA counties stratus clear
Sunday and Monday...while a strong coastal eddy will push clouds
to the coastal slopes in LA County with some spits of drizzle
possible. The Central Coast stratus remains a tough call on
Sunday...but should be mostly cloud-free on Monday as breezy
northeast flow forms in the morning. All of this adds up to a
mixed bag of temperature trends with the winds and stratus
evolution being the main drivers.
.LONG TERM...(TUE-FRI)
An upper level ridge of high pressure currently over north-central
Mexico will expand into California Tuesday through Thursday. This
will bring a gradual warming trend to the region...with interior
valleys approaching 100 degrees by Wednesday or Thursday. LA and
Ventura County coastal and valley areas should also see warming
with the air mass change and likely shrinking of the marine layer.
SBA and SLO counties on the other hand will see a ceasing of the
northwest flow and a return to onshore flow...which should
increase stratus coverage and largely neutralize the warming
trend. Both the GFS and ECMWF are advertising a weak trough
dropping down into California by as early as Friday...which would
enhance the marine layer and usher in some modest cooling. The GFS
ensemble members are in very good agreement with this timing
especially considering how far out this is...so did start the
cooling trend in the forecast.
&&
.AVIATION...08/18Z.
Upper level ridge of high pressure centered south of the area will
shift north while a trough of low pressure approaches Northern
California. And a mid level trough of low pressure over the area
will persist. Upper level moderate west-southwest winds will
prevail while mid level light southwest winds become light west
after 09/22z. Moderate onshore pressure gradient through 09/04z
and after 09/20z otherwise weak mixed northerly and onshore
gradient. Marine capping inversion at LAX was approximately 2.3kft
and VBG 2kft this morning and will differ by minus .3kft LAX and
minus 1kft VBG Saturday morning. Broken to overcast low level
cloud field is expected to be broken Saturday morning.
Marine layer at LAX at 1500Z is 2293 feet deep and the inversion
top is at 4764 feet with a temp of 20.6 degrees C.
KLAX...chance cigs 010-012 between 09/06-09/18z.
KBUR...chance cigs 012 after 09/12z.
virtually certain - 95-100%
very likely - 80-95%
likely - 60-80%
chance - 30-60%
very unlikely - 20% OR LESS
&&
.MARINE...08/200 PM...
Will continue with the gale watch for increasing northwest winds.
Northwest winds will likely increase Saturday afternoon and peak
Sunday in strength as well as areal coverage from Piedras Blancas
to San Nicolas Island. Otherwise small craft advisory for gusts
to 25 kt will exist in the meantime. Northwest winds will diminish
Monday but there is a chance SCA for hazardous sea conditions as
well as for northwest gusts to 25 kt through Wednesday.
Extra currents and surging along exposed south facing shores will
exist from swells originating from tropical cyclones Blas and
Celia and from the Southern Ocean through the period. TC Blas
was currently 1200 miles southwest of L.A. County and will weaken
while moving west-northwest today. Swell originating from Blas had
arrived thursday and will peak today and linger through Saturday.
Swells generated by Celia are expected to begin to arrive next
week Wednesday.
&&
.FIRE WEATHER...
08/300 PM...
Elevated fire danger will continue across interior sections
through the weekend. For this afternoon, the gusty onshore winds
will mostly be focused across the Antelope Valley and Los Angeles
County mountains. Over the weekend, west to north winds are
expected to become more widespread across interior sections,
including gusty sundowner winds across the western portions of
the Santa Barbara south coast and Santa Ynez mountains. Saturday
afternoon through Saturday night, wind gusts between 35 and 45 mph
will be common across the mountains, Antelope Valley, and western
portions of the SBA South Coast, then potentially ramping up to
between 40 and 50 mph on Sunday afternoon and night. On Saturday,
humidities will generally remain above 20 percent with the
exception of the Antelope Valley where values in the teens can
be expected. By Sunday afternoon and evening, more widespread
humidities falling into the teens (and possibly single digits
across higher mountains) can be expected across interior sections
bringing the potential for critical fire weather conditions. The
greatest threat of critical conditions exceeding 6 hours will be
the mountains and Antelope Valley on Sunday afternoon and evening,
where a fire weather watch has been posted.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Fire Weather Watch in effect from Sunday afternoon through
late Sunday night For zones 252>254. (See LAXRFWLOX).
Fire Weather Watch in effect from Sunday morning through
Sunday evening For zone 259. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 3 PM PDT Saturday For
zones 645-670-673-676. (See LAXMWWLOX).
Gale Watch in effect from Saturday afternoon through late
Sunday night For zones 645-670-673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...Kittell
FIRE...Gomberg
AVIATION...30
MARINE...30
SYNOPSIS...Sukup
weather.gov/losangeles
[top]
Area Forecast Discussion
National Weather Service San Francisco Bay Area
312 PM PDT FRI JUL 8 2016
.SYNOPSIS...Onshore flow and a deep marine layer will remain in
place through Saturday, with temperatures continuing well below
seasonal norms. Low cloudiness and patchy fog will spread back
well inland tonight. Approach of the tail end of a cold frontal
system moving into the Pacific Northwest will likely lead to some
enhancement of the coastal drizzle overnight into Saturday
morning, and also bring a slight chance of showers north of about
Pt Reyes. Breezy conditions are expected Saturday afternoon and
evening, and again on Sunday, in the wake of the frontal passage.
Dry weather and a modest warming trend then look to be in store
for our area the first part of next week, as an upper level ridge
of high pressure slowly rebuilds over California.
&&
.DISCUSSION...as of 02:50 PM PDT Friday...Aside from a few areas
of lingering coastal stratus, primarily from the vicinity of the
Golden Gate southward to around Half Moon Bay, sunny conditions
prevail districtwide. Clearing of the low cloudiness occurred a
bit faster than yesterday, and in conjunction with some
diminishment in the onshore pressure gradient, resulted in modest
warming of afternoon temperatures especially in the North and East
Bay valleys. The 2 pm temperatures at Concord and Livermore
Airports were 84F and 81F, respectively 8 and 6 deg warmer than
the same time Thursday. Consistent with this, latest data from
both the Bodega Bay and Ft Ord profilers show some diminishment of
the marine layer, though still maintaining a depth of about 1500
ft.
An unseasonably deep upper level low now centered about 500 miles
west of Seattle will continue moving southeastward towards the
northern Oregon coast. Models are in generally good agreement in
projecting that the tail end of its associated cold front will
dissipate as it brushes into the far northwestern part of our CWA
late tonight and Saturday morning. Consistent with latest model
output RH and QPF, and noting ECMWF MOS 12-hr KSTS POP of 16 for
12Z Sat to 00Z Sun, have introduced a slight chance of showers for
the coast and coastal hills north of about Pt Reyes Saturday
morning. Of potentially greater significance however is the ramp-
up in the marine layer likely to occur as this disturbance
approaches, potentially resulting in more substantial coastal
drizzle late tonight into Saturday morning. Although precip totals
would remain quite small, it could be sufficient to lead to
locally slick wet surfaces on roadways.
Saturday looks to be a bit cooler than today, and the coolest day
of either the previous or next several days. Widespread low
cloudiness and patchy fog is expected for the morning hours, locally
lingering into the afternoon around the Bays. Also expect onshore
winds to pick up as the day progresses with locally breezy
conditions by late afternoon continuing into the evening hours.
Sunday and on into the first part of next week, a modest warming
trend is expected, primarily inland areas, as as an upper level
ridge of high pressure begins to slowly rebuild over California.
This should also lead to some shallowing of the marine layer,
and diminishment of the night and morning inland extension of the
coastal stratus.
&&
.AVIATION...As of 11:00 AM PDT Friday...Clouds have burned off in
many spots earlier than forecast. Satellite shows a rapid decrease
over the past hour, so would expect VFR to happen in most spots.
Looking at IFR CIGs to return tonight. Moderate confidence.
Vicinity of KSFO...Conditions rapidly improving with VFR now
expected just after 18Z. Winds of 270 to 290 through the period
gusts close to 30 KT from 22Z to 04Z. Moderate to high confidence.
SFO Bridge Approach...Approach now clear. Should remain VFR until
around 04Z. Otherwise similar to KSFO.
Monterey Bay Terminals...Clouds quickly dissipating now with VFR
forecast 19Z to around 23Z. Winds generally 270 to 290 with speeds
to 12 KT for the afternoon into the evening. Moderate confidence.
&&
.MARINE...as of 2:34 PM PDT Friday...Surface high pressure over
the eastern pacific will will gradually rebuild on Saturday. A
weak cold front will slide south over the coastal waters during
the day with stronger winds expected going into Sunday. A mixed
northwest and southwest swell will continue to move through the
coastal waters through the forecast period.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...SF Bay until 11 PM
&&
$$
PUBLIC FORECAST: Blier
AVIATION: Bell
MARINE: Bell
Visit us at www.weather.gov/sanfrancisco
Follow us on Facebook and twitter at:
www.Facebook.com/nwsbayarea
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[top]
Area Forecast Discussion
National Weather Service Sacramento CA
238 PM PDT FRI JUL 8 2016
.Synopsis...An upper level low pressure system will continue to
bring below normal temperatures this weekend with breezy
conditions and slight chances for rain showers in the northern
Sacramento Valley. Temperatures will warm back to normal with dry
conditions by the start of the work week.
.Discussion...Water vapor imagery and RAP model 500 mb analysis
indicated a trough of low pressure positioned in the eastern
Pacific just off the coast of the Pacific Northwest this
afternoon. A general trough pattern is present across the west
coast, and a band of showers has developed in front of the
approaching system with some increasing clouds. Radar returns
have been light today, and no lightning has been detected as a
result of weak instability. Chances for showers will continue this
evening and stay confined to Shasta and Lassen counties.
Model forecasts are in good agreement with bringing the positively-
tilted trough onshore this weekend, which will continue to bring below
normal temperatures to NorCal and slight chances for showers in
the northern portions of the Sacramento Valley. The base of the
trough will move through Sunday, which will gradually end rain
shower chances. Temperatures will rebound to near normal on Monday
and continue through the week. Chances for rain will be minimal
under stable upper level conditions.
.EXTENDED DISCUSSION (Tuesday THROUGH Friday)
Little change next week as fairly flat ridging brings dry weather
and near normal high temperatures with dry weather. Delta breeze
influenced areas should see relatively cool nights and mornings,
with near normal lows elsewhere.
EK/Dang
&&
.AVIATION...
Mainly VFR conditions the next 24 hours. Isolated -SHRA will
be possible north of KRDD through Saturday. Marine stratus will
likely reach the Delta region again tonight. South to west winds
5-15 kt will continue into Saturday.
Dang
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
132 PM PDT FRI JUL 8 2016
.SYNOPSIS...
Night through morning low clouds and patchy fog will likely
continue to affect many coastal and some valley areas into the
weekend, with near or slightly below normal temperatures. Low
pressure passing to the north Saturday night into Sunday will
produce gusty sundowner winds in Santa Barbara County. Warming is
likely for inland areas next week as high pressure builds aloft.
&&
.SHORT TERM...(TDY-MON)
A low pressure system currently just west of Vancouver will drop
into Oregon tomorrow with a dry trough extending into central
California...then move eastward through Monday. Northwest winds
will strengthen Saturday night through Sunday night as a result.
Southern Santa Barbara County will likely need a wind advisory
Saturday night through Sunday night...while the LA Mountains and
the Antelope Valley should need one for late Sunday afternoon and
night. Gusts into the 50 mph range are likely in these areas
during the wind peak Sunday night. Monday will also see some
breezy northwest winds...but should be the weakest of the next
three days.
Stratus coverage and temperatures on Saturday should be similar
to today...save for less stratus over SBA and SLO counties thanks
to the dry front passage and the SMX-BFL pressure gradient
significantly weakening by 3 mb. The Northwest flow will likely
keep most of Ventura and southern SBA counties stratus clear
Sunday and Monday...while a strong coastal eddy will push clouds
to the coastal slopes in LA County with some spits of drizzle
possible. The Central Coast stratus remains a tough call on
Sunday...but should be mostly cloud-free on Monday as breezy
northeast flow forms in the morning. All of this adds up to a
mixed bag of temperature trends with the winds and stratus
evolution being the main drivers.
.LONG TERM...(TUE-FRI)
An upper level ridge of high pressure currently over north-central
Mexico will expand into California Tuesday through Thursday. This
will bring a gradual warming trend to the region...with interior
valleys approaching 100 degrees by Wednesday or Thursday. LA and
Ventura County coastal and valley areas should also see warming
with the air mass change and likely shrinking of the marine layer.
SBA and SLO counties on the other hand will see a ceasing of the
northwest flow and a return to onshore flow...which should
increase stratus coverage and largely neutralize the warming
trend. Both the GFS and ECMWF are advertising a weak trough
dropping down into California by as early as Friday...which would
enhance the marine layer and usher in some modest cooling. The GFS
ensemble members are in very good agreement with this timing
especially considering how far out this is...so did start the
cooling trend in the forecast.
&&
.AVIATION...08/18Z.
Upper level ridge of high pressure centered south of the area will
shift north while a trough of low pressure approaches Northern
California. And a mid level trough of low pressure over the area
will persist. Upper level moderate west-southwest winds will
prevail while mid level light southwest winds become light west
after 09/22z. Moderate onshore pressure gradient through 09/04z
and after 09/20z otherwise weak mixed northerly and onshore
gradient. Marine capping inversion at LAX was approximately 2.3kft
and VBG 2kft this morning and will differ by minus .3kft LAX and
minus 1kft VBG Saturday morning. Broken to overcast low level
cloud field is expected to be broken Saturday morning.
Marine layer at LAX at 1500Z is 2293 feet deep and the inversion
top is at 4764 feet with a temp of 20.6 degrees C.
KLAX...chance cigs 010-012 between 09/06-09/18z.
KBUR...chance cigs 012 after 09/12z.
virtually certain - 95-100%
very likely - 80-95%
likely - 60-80%
chance - 30-60%
very unlikely - 20% OR LESS
&&
.MARINE...08/200 PM.
Will continue with the gale watch for increasing northwest winds.
Northwest winds will likely increase Saturday afternoon and peak
Sunday in strength as well as areal coverage from Piedras Blancas
to San Nicolas Island. Otherwise small craft advisory for gusts
to 25 kt will exist in the meantime. Northwest winds will diminish
Monday but there is a chance SCA for hazardous sea conditions as
well as for northwest gusts to 25 kt through Wednesday.
Extra currents and surging along exposed south facing shores will
exist from swells originating from tropical cyclones Blas and
Celia and from the Southern Ocean through the period. TC Blas
was currently 1200 miles southwest of L.A. County and will weaken
while moving west-northwest today. Swell originating from Blas had
arrived thursday and will peak today and linger through Saturday.
Swells generated by Celia are expected to begin to arrive next
week Wednesday.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Fire Weather Watch in effect from Sunday afternoon through
late Sunday night For zones 252>254. (See LAXRFWLOX).
Fire Weather Watch in effect from Sunday morning through
Sunday evening For zone 259. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until 3 PM PDT Saturday For
zones 645-670-673-676. (See LAXMWWLOX).
Gale Watch in effect from Saturday afternoon through late
Sunday night For zones 645-670-673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...Kittell
AVIATION...30
MARINE...30
SYNOPSIS...Sukup
weather.gov/losangeles
Area Forecast Discussion
National Weather Service Phoenix AZ
125 PM MST FRI JUL 8 2016
&&
.SYNOPSIS...
A dry and stable airmass will remain across much of the desert
southwest through next week, giving the region a significant break
in the monsoon, with little or no chance for rainfall. Afternoon
temperatures on the lower deserts will remain near, or a few degrees
above normal through the period.
&&
.DISCUSSION...
Tonight through Saturday...
Increasing westerly flow ahead of a deep upper trof is expected to
continue to scour out any remaining monsoon moisture over extreme se
and eastern AZ during this period. The latest HRRR model run keeps
all convective activity confined to areas to the south and east of
Tucson and over the white Mountains, well outside of our cwa this
afternoon/evening, with even less activity on tap on Saturday. 500
mb heights in the 593-595 dm range, 500 mb temps in the -4C to -5C
range, along with mostly clear skies will allow temperatures to rise
a bit above normal again on Saturday, with lower desert highs mostly
in the 108-112 degree range.
Sunday through next Friday...
Further drying is expected across the region during this period as a
very deep, and cold upper low center (for July) moves across the
Northern Rockies during the early part of next week, bringin a
chance for some rare mid-summer snowfall to the higher elevations of
MT/WY. To the south of this low center, a band of anomalously strong
westerlies are expected to move across the Great Basin/northern AZ
region Sun-Tue. 700mb winds are expected to reach 30 kts, or even
greater across parts of northern AZ, which are in the 99% (or
higher) climatological percentile for this time of year, according
to the NAEFS percentile tables. The main impact from this belt of
very strong winds will be to mix drier air down to the sfc across
the region, with sfc dewpoints likely falling into the 30s, or even
20s across most of our cwa. The dry airmass, combined with a bit of
cooling aloft will likely allow many outlying lower desert locations
to see lows in the 70s each night. These cooler temperatures,
combined with the lower RH`s will result in the nights feeling
noticeably more pleasant than what we typically see this time of
year. Highs will be near, or just a bit above normal, mostly in the
105-110 degree range across the lower deserts. PWATS across the
region will also be well below normal, in the 0.50-0.75 inch range,
which is 1-2 SD below normal. Needless to say, chances for
rainfall/thunderstorms during this entire period will be basically
at zero, as our extended break in the monsoon continues.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA and KSDL:
Generally clear skies to continue with some afternoon high based cu
mainly situated over the high terrain to the east. Winds will follow
typical diurnal patterns with occasionally gusty afternoon westerlies.
Southeast California/Southwest Arizona including KIPL and KBLH:
Southerly winds through the afternoon with winds shifting westerly at
KIPL this evening. Winds will be breezy at KBLH this afternoon, but
gusts should mostly remain less than 20 kts. Skies to remain clear.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Sunday through Thursday...
Unusually dry conditions to settle over the area throughout the
weekend lasting through much of next week. With temperatures
hovering near a warm seasonal average, minimum afternoon humidity
levels will fall to around 10% over lower elevations, and 15-20% in
higher terrain. Overnight recovery will only be fair. Occasionally
breezy southwest afternoon winds will affect the region, however
speeds will remain well below any critical thresholds. Overall,
weather conditions will mirror a typical early/mid June versus mid
July.
&&
.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...Percha
AVIATION...Kuhlman
FIRE WEATHER...Kuhlman
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
301 PM CDT FRI JUL 8 2016
.SHORT TERM...(This Evening through Saturday)
Issued at 256 PM CDT FRI JUL 8 2016
Despite some morning clouds and an easterly wind across the area,
temperatures have risen into the upper 80s to near 90, save the far
south which is still holding in the lower 80s as clouds continue
there. Several small waves noted in the flow, one of which is
approaching central kansas at this hour. Experimental HRRR has a
relatively reasonable solution that brings the MCV into the CWA and
interacts with an outflow moving up from the south out of earlier
convection, and brings a round of showers and thunderstorms across
western and southern areas later this afternoon into the evening.
Wind fields are weak, although CAPE could be enough to generate some
wind with storms that develop. LLJ is only around 25kts overnight,
but may redevelop storms over central/south central Kansas overnight
and move eastward across mainly our southern counties. Only
carrying slight chance to low chance PoPs given coverage and
uncertainty. Lows tonight forecast near 70 with highs on Saturday
in the upper 80s to low 90s.
.LONG TERM...(Saturday Night through Friday)
Issued at 256 PM CDT FRI JUL 8 2016
No major changes made in the extended with still some variances in
model guidance on timing and coverage of precipitation. Best chances
for seeing more widespread showers and thunderstorms will be with
the arrival of a cold front on Tuesday. More details below.
Temporary ridging aloft Saturday night and Sunday should keep much
of the area dry. Strong upper trough across the Inter Mountain West
deepens a lee trough over the Rockies Sunday and Monday, increasing
southerly winds at 10 to 15 mph sustained in the afternoon. Gusts up
to 30 mph are possible, alleviating slightly the hot and humid
conditions with readings in the lower and middle 90s.
The aforementioned upper trough ejects over the northern plains
Monday evening and Tuesday, surging the cold front into north
central KS in the overnight hours. Guidance continues to exhibit
high confidence in this scenario and have raised pops into the
likely category near the KS and NE border. Ample mixed layer CAPE
and effective shear parameters near 40 kts could develop a few
strong to severe storms over north central areas. This activity
pushes south and east on Tuesday, spreading chances towards the
entire CWA.
Models differ some Tuesday evening onward as the frontal boundary
hangs up across the area. Subtle impulses embedded within the
northwesterly flow aloft signals multiple rounds of thunderstorms,
especially on Wednesday evening. Temps hover near normal values in
the lower 90s for highs and low 70s for overnight lows, likely to
drop into the 80s by the end of the period as the frontal boundary
shifts south of the area.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1226 PM CDT FRI JUL 8 2016
Low confidence in convection for this TAF cycle, but enough of a
signal in several models to at least get a tempo group for late
this afternoon, with shra/ts developing over central KS attm.
Winds east shift slowly south and will be variable from storms and
outflow in the area.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Prieto
AVIATION...67
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1227 PM CDT FRI JUL 8 2016
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 326 AM CDT FRI JUL 8 2016
An amplified upper level trough across the upper midwest early this
morning will move east across the eastern Great Lakes Tonight. The
upper flow across eastern KS will weaken and shift to the northwest
through Tonight as an upper level ridge amplifies across the high
plains.
At the surface a weak cold front front extended from northwest MO,
southwest through Topeka, then west southwest across western KS. An
out flow boundary extended from northwest OK, northeast into south
central KS, then extended east across southeast KS. North of the
boundary a few showers and thunderstorms continued to develop across
southeast KS early this morning. A complex of storms that developed
across the northern TX PNHDL has amplified an MCV across southwest
KS.
Most models show the weak front becoming stationary south of the CWA
through the mid morning hours with frontolysis occurring through the
afternoon hours across western KS. The NAM and GFS models show the
MCV over southwest KS shifting east across the southern counties of
the CWA through the late morning and afternoon hours which may
provide enough ascent for showers and thunderstorms to develop. If
these solution are accurate, then there will be chances for showers
and thunderstorms south of I-70, beginning across the southwest
counties during the late morning hours and expanding east across the
southern half of the CWA during the early and mid afternoon hours.
The mesocale models, such as the HRRR, WRF and RAP show the MCV
weakening and no precip developing through the day.
Highs today will reach the upper 80s to lower 90s with heat indices
in the mid to upper 90s
Tonight, all the numerical models show that any complex of storms
that develop across eastern CO during the evening hours will track
southeast across southwest KS into northern OK. There could be
enough isentropic lift after mid night on the northern and eastern
edge of the deeper moisture return across central and western KS for
scattered elevate thunderstorms to develop across the southwest and
southern counties of the CWA.
.LONG TERM...(Saturday through Thursday)
Issued at 326 AM CDT FRI JUL 8 2016
The weekend will see slight chance POPs over the area to begin
with. Weak isentropic lift sets up in the morning over northeastern
Kansas on Saturday as weak shortwaves pass overhead into the day.
Forcing is weak overall, so much of this could just result in
enhanced cloud cover rather than any widespread showers and isolated
thunderstorms. There will still be plenty of instability with
dewpoints still forecast to be in the upper 60s and low 70s. As a
North Pac Low deepens and digs into the Pacific Northwest, mid to
upper level ridging will amplify over the Central and Northern
Plains into Sunday and should see mainly dry conditions set up over
the region with good mixing into the afternoon. Therefore,
expecting temps to rise into the low and possibly mid 90s. This
will bring heat index values up to around or into the low 100s. Not
anticipating headlines at this time for an advisory though. It may
be something to watch if we can hold off more cloud cover and temps
rise a bit more.
Monday into the Monday night time frame, the North Pac Low will
deepen and take on a negative tilt as it lifts into the Northern
Plains. A modified cold boundary will move into the Central Plains
and stall out as this system lifts into Central Canada. Greatest
chance POPs will likely be overnight Monday as the best shear zone
advects overhead with the mean trough. At least this appears to be
the best chance for any organized storms to form. A strong EML will
have also set up over the Central Plains, so it may be too capped
for development to take place, but mainly elevated storms look like
the best possibility which if they form could create some strong
gusty winds and hail. Still difficult to eliminate precip chances
out of subsequent periods as quasi-zonal flow regime sets up and
weak impulses traverse overhead. Still looks like possibility
remains for off and on showers and storms into the Friday time frame
with a stationary boundary likely lingering over the Central Plains
into the Mid-MS Valley. With no strong movement in the overall
pattern, expecting temps to remain seasonal with heat index values
around the upper 90s and 100 degree mark.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1226 PM CDT FRI JUL 8 2016
Low confidence in convection for this TAF cycle, but enough of a
signal in several models to at least get a tempo group for late
this afternoon, with shra/ts developing over central KS attm.
Winds east shift slowly south and will be variable from storms and
outflow in the area.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Drake
AVIATION...67
AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
406 PM CDT FRI JUL 8 2016
.Discussion...
Current upper level synopsis shows a ridge centered near the
northern Texas panhandle and a trough over the eastern third of the
country. A surface inflection of the Bermuda ridge does extend
across Florida to the western Gulf of Mexico. Current convection has
already begun to wane and will diminish over the next few hours with
loss of daytime heating. Many locations did get a brief cool down
from showers and storms but that soil moisture may convert back into
higher dewpoints overnight. Even though New Orleans dropped below 80
for the first time in several days after a thunderstorm today (it
has since warmed back into the upper 80s) not sure the temperature
will fall below 80 tonight. Decided to hold off on re-issuing the
heat advisory to allow overnight shift to monitor lows in addition
to thinking that there will be more coverage tomorrow. And speaking
of the forecast Saturday...the upper ridge to the west that extends
over the CWA will begin to weaken locally and retrograde westward.
This decreased subsidence with possibly slightly more column
moisture should result in more numerous showers and thunderstorms.
This will moreso be the case going into Sunday as a weak trough
develops from the Tennessee Valley, extending southwestward towards
the CWA. Thus have increased pops on both days this weekend to 20-
40% Saturday and 50% Sunday.
Not much change expected throughout next week in terms of rain
chances. Daily afternoon pops should be 30-40% each day the local
area will be under a shear zone between Bermuda ridge that moves
into the western Atlantic and a trough moving east across the
northern half of the country.
MEFFER
&&
.AVIATION...
VFR conditions are expected to dominate for the rest of this
afternoon through Saturday morning. The only exceptions will be
briefly lower conditions due isolated SHRA/TSRA, affecting KMSY,
KNEW, KASD, KGPT and KHUM mainly through 23z. There may also be
another round of MVFR to IFR conditions due to BR/light fog at KMCB
late tonight/early Saturday morning.
&&
.MARINE...
Bermuda surface ridge extending across the Gulf of Mexico will keep
flow onshore throughout the forecast period. The local coastal
waters will continue to see the typical diurnal wind
increase/decrease as nocturnal winds rise to 10 to 15 knots which
will carry over into the morning hours and then drop down the rest
of the day closer to 10 knots or slightly less. This should continue
into the weekend. Nocturnal sh/ts will also develop during the late
night and early morning hours through the next several days. Winds
will begin to shift to a more SE direction by Sunday as the ridge
shifts northward.
&&
.DECISION SUPPORT...
DSS code: Green.
Deployed: None.
Activation: None.
Activities: None.
Decision Support Services (DSS) Code Legend
Green = No weather impacts that require action.
Blue = Long-fused watch, warning, or advisory in effect or
high visibility event.
Yellow = Heightened impacts with short-fused watch, warning
or advisory issuances; radar support.
Orange = High Impacts; Slight to Moderate risk severe; nearby
tropical events; HazMat or other large episodes.
Red = Full engagement for Moderate risk of severe and/or
direct tropical threats; Events of National Significance.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 76 93 74 94 / 10 20 20 50
BTR 77 94 76 94 / 10 20 10 50
ASD 79 94 76 93 / 10 40 20 50
MSY 81 94 79 92 / 10 40 10 50
GPT 80 92 76 91 / 10 30 20 40
PQL 78 93 76 94 / 10 30 20 40
&&
.LIX Watches/Warnings/Advisories...
LA...Heat Advisory until 7 PM CDT this evening for LAZ060>064.
GM...None.
MS...None.
GM...None.
&&
$$
[top]
Area Forecast Discussion
National Weather Service Shreveport LA
337 PM CDT FRI JUL 8 2016
.DISCUSSION...
The upper air ridge across the ARKLATEX late this afternoon is
gradually breaking down/shifting East away from the region,
courtesy of upper air troughiness draped from the Great Lakes
Region to across the Central Plains. Although the ridge is doing a
decent job at keeping storm chances at bay, as shown by sea-
breeze convection having been confined to Southern LA, but can not
rule out a few showers making it to central LA later this aftn.
Furthermore, will also need to pay close attention to Eastward
propagating thunderstorm activity that have been plaguing portions
of the Central Plains and mid-Mississippi Valley most of the day,
aided by a nearby cold front. If an outflow boundary shift South
towards the region, it could serve as a focus for CI later this
aftn/early evening as hinted at by the HRRR solution. Tonight
appears to be the slightly better opportunity for precipitation
especially for the Northern zones, as the Southern periphery of
the UA trough swings across the area and provide a bit of large
scale ascent. Otherwise, slightly gusty South to Southwest winds
have prompted temps to warm into the 90s or 2 or so degrees above
normal. Lack of beneficial rainfall within the last few weeks and
a downslope wind component thus keeping temps hot, will lead to
soils continuing its drying effects. This is especially seen
across the Western zones as dewpoints are a few degrees lower
than this time yesterday afternoon. It is still going to take some
time for significant drying to take place but the process is
underway.
As the upper air ridge shifts to the Southeast CONUS this weekend,
Northwest flow aloft will prevail and embedded disturbances within
the flow aloft along with a slowly Southward sagging cold front,
will lead to the return of precipitation chances, particularly
across Northern and Eastern zones. The ridge is anticipated to make
a return early next week thus encouraging the retreat of the nearby
frontal boundary and hence diminishing chances for significant
widespread precipitation. The only precipitation potential will be
diurnally driven sea-breeze convection mid-late week as hinted at
by long term solutions.
Temperatures will remain at/above normal throughout the extended
forecast though humidities will ever so slightly be lowering. So
the question begs as to whether or not to extend the Heat
Advisory beyond today. Highest dewpoints were noted across the
Eastern zones late this aftn, coinciding with the highest heat
indices and where a portion of the Heat Advisory is currently in
effect. Tomorrow, temperatures may be a few degrees cooler than
today /albeit still warm/ given the exiting ua ridge corresponding
to lowering 500 mb height fields. The soils will continue to dry
and so will the humidity. Will therefore hold off on extending the
Heat Advisory attm, but can not rule out heat indices still
hovering around/slightly above 100 degrees across the Eastern
zones.
.AVIATION...
VFR conditions will continue to dominate the aviation forecast over
the next 24 hrs. Some early morning low clouds ceilings may be
observed in Deep East Texas...but elsewhere they will be scattered.
Widely scattered shra/tsra activity may affect our Arkansas
terminals tomorrow afternoon...but at this time the chances are too
low to mention in the taf. Southerly winds will continue to prevail
through the period. /11/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 77 95 77 96 / 10 10 10 20
MLU 77 94 76 94 / 10 30 20 30
DEQ 76 93 75 93 / 20 30 20 30
TXK 77 95 77 94 / 20 20 20 30
ELD 77 94 76 94 / 20 30 20 30
TYR 77 96 77 96 / 10 10 10 10
GGG 77 96 77 96 / 10 10 10 10
LFK 77 95 77 96 / 0 20 0 10
&&
.SHV Watches/Warnings/Advisories...
AR...Heat Advisory until 7 PM CDT this evening for ARZ072-073.
LA...Heat Advisory until 7 PM CDT this evening for LAZ001>006-010>014-
017>022.
OK...None.
TX...Heat Advisory until 7 PM CDT this evening for TXZ151>153-165>167.
&&
$$
29/11