Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/12/18
Area Forecast Discussion
National Weather Service Billings MT
929 PM MDT Wed Jul 11 2018
Water vapor imagery shows a weak shortwave moving through western
MT with monsoonal moisture plume extending from the southern Great
Basin to the far southeast corner of MT. Upper air analysis shows
a nice PV max associated with the western MT wave, and divergence
beginning to increase due to a jet max. 700mb analysis shows a
developing weak circulation south of Dillon, and in this region we
are starting to see an increase in cloud development. Elsewhere
across western and central MT, air mass has been too dry for
anything to develop. Precipitable waters at 00z remain elevated
across eastern MT, with values of 0.74 inches at GGW to 1.28 at
RAP. Latest HRRR runs are backing off on shower development
overnight, but feel this is the wrong trend as ascent is
increasing and elevated instability is in place. Cloud development
to our west should be a sign of what will begin to happen in our
west before midnight. Overnight into Thursday morning, isolated
showers (scattered in our SE cwa) are a good bet as this energy
moves through the area from west to east. Have adjusted/expanded
pops slightly. For Billings, look for isolated showers between
roughly 2-9 am, with a rumble of thunder also possible.
.SHORT TERM...valid for Thu and Fri...
Isolated thunderstorms were occurring in the monsoonal flow over
WY this afternoon. Model consensus continued to bring storms into
Sheridan County this evening. Also cannot rule out some convection
making it into far SE MT, given the NE flow into the area, so had
20 PoPs over the far SE. A stronger shortwave pushes NE into SE MT
overnight and will bring more thunderstorms to this area. There
will be a slight chance of storms further W into Yellowstone
County as well, so had PoPs covering this. Models showed
precipitable waters increasing to an inch to /1.25/ inches
tonight, so heavy rain is possible with the thunderstorms. Increased
cloud cover will help keep min temperatures in the low 60s
central and E. Kept lingering PoPs in the SE Thursday morning,
then had PoPs over and near the southern mountains in the
monsoonal regime in the afternoon and evening. Not expecting any
severe storms during the period based on SREF low CAPES and shear.
Soundings supported temperatures in the low to mid 80s on
Thursday. A warm 850 mb airmass will keep lows in the 50s to low
60s Thu. night. Heights rise on Friday and there will be a break
in the monsoonal flow for a dry day. Highs will reach the low to
mid 90s, and mins Fri. night will be well into the 60s over the E
with 850 mb temperatures around +27 degrees C. Arthur
.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...
Very little in the way of changes this afternoon, as models
continue to be consistent.
A cold front will move through the area Saturday, as a trof moves
across the US/Canada border. FROPA itself looks relatively dry
during the day, with only a few showers/thunderstorms in high
terrain. Precip does appear to lag a bit behind the front
however, resulting in more widespread showers and thunder late in
the evening and overnight Saturday night. Temps will be cooler on
Sunday, behind the FROPA with highs dropping down into the 70s.
Precip will linger across much of the region Sunday, as front is
slow to move south. Main trof axis finally clears to the east on
There is a bit of a chance for isolated to scattered showers and
thunder Monday across extreme southern zones, as a weak
disturbance slides through the flow and capitalizes on monsoonal
moisture trapped below the ridge. Otherwise mainly dry conditions
should prevail through the beginning of the workweek. Temps will
increase through the beginning of next week as shallow ridging
builds in from the west, but temps are expected be around normal.
Mainly VFR conditions will prevail through the TAF period. A weak
disturbance moving into the region will bring isolated to
scattered showers and isolated thunderstorms to portions of the
area overnight. Showers/thunderstorms will linger over southern
areas on Thursday, with dry conditions expected elsewhere. STP
.PRELIMINARY POINT TEMP/POPS...
Thu Fri Sat Sun Mon Tue Wed
BIL 061/084 062/094 064/090 058/079 058/088 060/088 060/090
22/W 00/U 01/U 22/T 11/U 21/U 10/U
LVM 052/081 053/091 054/086 052/079 050/085 052/086 052/087
21/U 00/U 01/U 22/T 21/U 11/U 10/U
HDN 062/086 061/095 063/091 060/080 056/088 059/088 060/091
22/W 10/U 01/U 22/T 11/U 11/U 10/U
MLS 063/086 063/093 067/092 060/079 057/087 060/087 061/091
22/W 00/U 01/U 22/T 11/U 11/U 10/U
4BQ 062/084 061/092 067/095 060/078 057/086 059/087 061/091
33/T 11/U 01/U 43/T 21/U 12/W 10/U
BHK 061/083 060/089 064/091 057/077 054/083 057/084 057/086
22/W 00/U 01/U 32/T 21/U 11/U 10/U
SHR 058/082 057/091 058/090 056/078 052/086 056/085 056/089
33/T 21/U 11/U 33/T 21/B 32/W 11/U
Area Forecast Discussion
National Weather Service Elko NV
308 PM PDT Wed Jul 11 2018
.SYNOPSIS...Monsoon moisture across central Nevada will result in
afternoon and evening showers and thunderstorms through Saturday.
Some thunderstorms could contain heavy rainfall potentially
leading to flash flooding. Meanwhile, much of northern Nevada will
remain dry with above normal temperatures through early next
.SHORT TERM...Tonight through Friday. Scattered showers and
thunderstorms across central and east central Nevada will continue
through the evening hours before diminishing overnight. Moisture
plume will remain southeast of a line from northwestern Nye county
to central Eureka county to the Ruby Mountains eastward. PWATS
around 1 inch with ample instability will be pushed south of Elko
county Thursday as a weak trough passes to the north and
northeast and northerly flow expands north of I-80. Temperatures
will remain above normal where cloud cover is absent.
.LONG TERM...Friday night through next Wednesday.
Subtropical ridge rebounds over the Great Basin states as trough
moves downstream. Rotating around the high core, the GFS depicts a
disturbance that skirts the nrn NV border on Saturday. Areal
thunderstorm coverage expands and reaches the northern border.
Once this disturbance passes nrn NV, drier air seeps into the
Humboldt and Elko counties as precipitable water dips below three
quarters inch /0.75/. Across central NV, diurnally driven storms
will form each afternoon.
Big "bubble" centered over the Great Basin may form early next
week, and if it does, then expect very hot weather. The EC models
and ensemble solutions have not shown this consistency, but hint
that the high core will be centered along the Nevada and Utah
border. If 700 mb temps reach 20C, then 100+ readings will be
common across the area. The confidence factor just not high enough
to show this potential heat wave in the actual gridded products.
Monday and Tuesday appear to be the hottest days, the question
being how hot.
The operational GFS hints that the next monsoonal surge, via
California and then spilling into Nevada, will be next Wednesday.
This all depends where the high core will be positioned by mid
.AVIATION...Two different air masses splits the region with KELY and KTPH on
the wet side as TSRA will be in the vicinity at both sites. Gusty
outflow winds are likely at both sites, but brief heavy rain
showers may occur if the cell moves directly overhead.
KEKO is on the delineation between the two air masses, but the
HRRR model keeps storms on the eastward side of the Rubies. This
means the KEKO receives no storms today.
Dry and stable air mass prevails for KWMC and KBAM with nocturnal
.FIRE WEATHER...Scattered showers and thunderstorms will continue
across the central Nevada zones 455, 454 and 457 Thursday through
Saturday as monsoon moisture remains in the area. Drier
conditions are expected north of US-50 across northern Nevada.
North winds will increase tonight across the I-80 corridor but
remain below critical levels. Above normal temperatures and low
daytime relative humidity will continue in zones 467, 468, 469 and
470 but winds will remain well below critical levels through at
least the weekend.
.HYDROLOGY...Slow movement of showers and thunderstorms combined
with recent rainfall across some parts of central and eastern
Nevada will increase the potential for flash flooding Thursday.
Brief but heavy rainfall could result in flash flooding of
normally dry washes, canyons, and streams. The Hogan, Echo and
Boone Springs burn scars will be susceptible to debris or mud
flows through this evening before the flash flooding threat shifts
farther south Thursday.
Flash Flood Watch until 11 PM PDT this evening for Northeastern
Nye County-Northwestern Nye County-Ruby Mountains/East Humboldt
Range-South Central Elko County-Southeastern Elko County-White
Flash Flood Watch from Thursday morning through Thursday evening
for Northeastern Nye County-Northwestern Nye County-White Pine
Area Forecast Discussion
National Weather Service Midland/Odessa TX
643 PM CDT Wed Jul 11 2018
.DISCUSSION...Please see 00Z Aviation discussion below.
.AVIATION...As of 6:30 PM CDT Wednesday...As the sun sets in the
west so does the convection. The convection over the Guadalupe and
Sacramento Mtns are quickly waning as the heating wanes. There are
a couple of cells bravely hanging on in the adjacent Plains...
mainly in Lea County but they will go the way of their mountain
brethren in the next couple of hours.
The NAM (North American Monsoon) will be very active the next
several days. Expect a repeat performance of the NAM tomorrow...if
not a bit more as moisture surges north out of old Mexico. The
HRRR shows some cells tomorrow morning in the NM Plains...but
taking in the fact that the HRRR hasn`t done well the last several
days I have my (considerable) doubts.
Since timing and location of convection will be near impossible to
predict will keep the TAF`s simple (VFR) and will amend as needed
(mainly KCNM and KHOB). Pilots should keep in mind that flight
conditions will be very turbulent over the Guadalupe and
Sacramento Mtns as convection fires up in the aftn.
.PREV DISCUSSION... /issued 205 PM CDT Wed Jul 11 2018/
Deep easterly flow will continue through the rest of the week and
into the weekend. With no significant upper level disturbances
moving westward over the area, thunderstorm development will be
favored in the the higher terrain (and immediate adjacent plains)
where intense diurnal heating and upslope flow enhance activity.
Weak steering flow suggests locally heavy rainfall likely in the
Precipitation chances look to decrease some early next week as
flow aloft turns more northeasterly and upper ridge attempts to
build more into the region. Still, a slight chance of storms
is warranted in the higher terrain due to intense diurnal heating
and upslope flow.
Temperatures will be at or slightly above normal through the
early next week.
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 73 96 74 96 / 10 10 10 20
Carlsbad 70 94 70 95 / 20 30 20 30
Dryden 72 98 73 99 / 0 0 0 0
Fort Stockton 70 94 71 95 / 10 10 10 10
Guadalupe Pass 67 86 67 84 / 20 30 30 40
Hobbs 68 90 68 91 / 20 20 20 20
Marfa 62 89 63 89 / 20 20 10 20
Midland Intl Airport 73 96 73 96 / 10 10 10 10
Odessa 72 96 73 96 / 10 10 10 10
Wink 72 96 72 98 / 10 10 10 10
Area Forecast Discussion
National Weather Service Phoenix AZ
900 PM MST Wed Jul 11 2018
Scattered showers and thunderstorms capable of producing flash
flooding, gusty winds, and small hail are expected this afternoon
and evening over the region. A Flash Flood Watch is in effect
until early Thursday morning for most of south central and
southwest Arizona and southeast California. Monsoon moisture
levels will continue to remain high enough this week to cause
isolated to scattered showers and thunderstorms daily across most
of the region, with chances decreasing for the latter part of the
work week before increasing again later this weekend. Temperatures
will remain near to slightly below normal into next week.
A rather active afternoon/evening across the region so far, as a
combination of a weakening MCV and a larger-scale inverted trof
helped to trigger scattered-numerous thunderstorm activity across
our entire cwa. The 03Z PSR balloon sounding is also showing a
record (for the date) PWAT of 2.08 inches. Areas that were most
impacted so far were across parts of eastern Riverside County,
including Desert Center and Joshua Tree National Park in SE CA,
and the Wickenburg area of South-Central AZ. Although the overall
amount of convection is diminishing, the latest HRRR high-res
model output (which is supported by the latest SPC mesoanalysis
showing 5-10 kts of convergent flow at 850/925mb) is now showing
thunderstorm activity continuing over the next few hours across
much of South-Central AZ (including the Greater Phoenix Area). The
main threats from this activity will be locally heavy
rain/flooding and gusty winds. as far as the Flash Flood Watch is
concerned, areas across SE CA have been dropped from the watch
area, with the Watch still remaining in effect across parts of La
Paz County and most of South-Central AZ.
.PREVIOUS DISCUSSION... Scattered showers and thunderstorms are
ongoing across south central Arizona including the Phoenix metro
along with portions of Riverside and northern Imperial Counties in
southeast California. The first area is associated with the
larger-scale inverted trough that triggered convection over La Paz
County earlier today and is continuing to move westward into
southeast California, while the second area is northwest of a
weakening/dissipating MCV feature that is currently over southeast
Arizona. Although we will continue to see some gusty winds up to
50 mph and blowing dust with these storms, locally heavy rainfall
continues to be the greatest threat and should be the only one
that extends into the evening hours. Precipitable water values
continue to be in the 1.5-1.9 inch range across the region, with a
modest decrease evident towards the higher terrain north and east
of Phoenix. Storm motions to the west have been a bit faster than
expected over southeast California where DCAPE values are closer
to 1000 J/kg and outflows have been a bit stronger. However, they
have not been fast enough to keep rainfall totals down due to the
efficient rain rates falling from these storms, so we have
extended the Flash Flood Watch into our Riverside County zones and
a small portion of northern Imperial County that includes zone
Storm motions over south central Arizona continue remain below 10
mph due to very weak shear and steering flow with DCAPE values
generally remaining below 700 J/kg (low enough to help slow down
outflow propagation, but enough to trigger new cells and kick up
some dust). Although hi-res models continue to show quite a bit
of variability in how convection will evolve today, the broader
ensemble is trending towards ending convection for most areas
during the early evening hours. This seems fairly reasonable due
to the lack of strong outflows from convection north of Phoenix
which is limiting the strength and coverage of convection, but we
still anticipate convection currently moving north through the I-8
corridor to hold together and/or trigger outflows that help
increase convective coverage over the Phoenix metro in the next
few hours. There are still a few hi-res model runs showing
convection may continue over the lower deserts including Phoenix
and possibly the higher terrain north and east of Phoenix, but the
MCV feature that appears to be dissipating over the higher
terrain of southeastern Arizona makes this less likely. We will
just have to watch out for another MCV developing from our ongoing
convection, which would really be the only reason the flash flood
threat would continue deeper into the late evening and overnight
hours. For now, we will continue to maintain the Flash Flood Watch
through 2 am tonight just in case a new MCV is able to develop.
We should see at least a slight decrease in convective activity
tomorrow across the region as the inverted trough finally pushes
west of the CWA and the atmosphere becomes a bit more worked over
from today`s convection. Assuming a new MCV does not materialize,
larger-scale dynamics and vorticity advection should be much
weaker tomorrow, so the excessive rainfall threat should be much
less tomorrow. However, now that deep monsoon moisture is in
place, we will have a threat for mainly afternoon/evening showers
and storms in the area each day until that moisture substantially
decreases, especially over south-central Arizona. Model guidance
is in pretty good agreement that convective coverage should
decrease even more on Friday as precipitable water values fall
closer to 1.2-1.5 inches without a clear trigger for convection
aside from terrain and daytime heating. The upper high becomes
somewhat ill-defined and centered off to our northwest, with weak
low/mid level steering flow from the southwest. Friday and
Saturday should be the warmest days with highs in the lower to mid
100s over the Phoenix metro and upper 100s over the lower deserts
of southwest Arizona and southeast California.
More favorable monsoon conditions to return later this weekend at
some point between Saturday and Monday as another easterly wave
from the Gulf of Mexico pushes west into northern Mexico and the
Desert Southwest to bring increasing moisture and upper-level
support for convection. In addition, the upper high will set up
to our northwest in the vicinity of southern Nevada and steering
flow will strengthen out of the northeast which is a favorable
direction to bring high terrain storms into the deserts. Our
current forecast favors the ECMWF which shows a more pronounced
wave, though there is still considerably uncertainty in the timing
and potential strength of a such a wave at this time. As moisture
increases, high temps start to trend back down slightly on Sunday
and Monday before increasing by the middle of next week once the
wave has moved west of the region.
South-Central Arizona including KPHX, KIWA, and KSDL:
Expect the chance for showers and thunderstorms to continue through
the rest of the evening, with activity gradually diminishing
after midnight. Winds to remain mainly from a westerly direction
through the rest of the evening (outside of thunderstorms), then
gradually becoming easterly after midnight. Thursday should be a
much quieter day, with light easterly winds in the morning
becoming westerly by late afternoon.
Southeast California/Southwest Arizona including KIPL and KBLH:
Rather quiet conditions are expected through the taf period, with
just a very slight chance for thunderstorms tonight. Winds to
remain mainly from a southeasterly direction at KIPL and a
southerly direction at KBLH through the TAF period.
Aviation Discussion not updated for amended TAFs.
Saturday through Thursday: Low grade monsoon conditions will
exist Friday and possibly Saturday as drier air moves over the
region. During this period, afternoon thunderstorms will mainly be
confined to the higher terrain north and east of Phoenix, but we
cannot completely rule out a few storms making their way to the
lower elevations of south-central Arizona. Despite the drier air,
overnight recoveries will still be fair to good while daytime
humidity minimums will be at or above 15-20%. More moist air works
its way into the region on Sunday and looks to stick around
through early next week bringing a possible uptick in afternoon
convection. Winds will remain light throughout our extended period
except near thunderstorms where gusty and erratic winds can be
.SPOTTER INFORMATION STATEMENT...
Spotters may be needed late this afternoon and evening.
AZ...Flash Flood Watch until 2 AM MST Thursday for Azz534-534-537-538-
Area Forecast Discussion
National Weather Service Blacksburg VA
1032 PM EDT Wed Jul 11 2018
A cold front will slide south of the area tonight before
stalling over the Carolinas Thursday. High pressure will build
across the region from the north Thursday and remain in place
through much of the weekend. Increasing heat and humidity should
return along with better chances of showers and storms ahead of
the next cold front by early next week.
.NEAR TERM /THROUGH THURSDAY/...
As of 740 PM EDT Wednesday...Isolated strong to at times severe
thunderstorms still continue, with the threat area primarily
from Campbell to Wilkes Counties south/eastward at this hour.
Areas north and west have stabilized. Air mass in this area from
Charlotte to Wilkes Counties east/south remain moderately
unstable with surface- based CAPEs around 2000 J/kg with high
downdraft CAPE values of 900-1100 J/kg per SPC mesoanalysis.
Strongest cells currenty exist in Charlotte County and into the
Danville/southern Pittsylvania County vicinity, and we are
continuing to watch storms in Nelson and Albemarle Counties that
may brush Buckingham County. Strongest thunderstorms capable of
mainly damaging winds, though spotters report a few instances
of pea-sized hailstones and so sub-severe hail can`t be ruled
out either. Expectation is for ongoing storms to push southeast,
weakening more quickly after sunset as surface cold front
progresses into north- central NC, but lingering showers may
still remain until midnight per HRRR from Southside into the NW
NC mountains. Kept slight to low Chance PoPs overnight in these
High pressure should ridge down overnight - which will afford
drier dewpoints to advect southward, along with some slight
enhancement to north-northeast winds. Did opt to raise wind
speeds up some midnight and into overnight, and combination of
drying air mass and some light northeast winds may keep fog
coverage at bay overnight. Otherwise, opted to make no other
changes at this time.
Previous discussion issued at 245 PM...
Initial band of pre-frontal westerly flow convergence aided convection
continues to sink southeast west of the Blue Ridge this afternoon in
advance of the actual surface cold front advancing south into the Blue
Ridge. Still expecting overall better coverage including perhaps
isolated stronger storms to finally taking shape over the south/east
as moisture and the front work into increasing instability through
late afternoon. This still suggested via several short term solutions
including the HRRR in having at least a broken band of showers/storms
pivot south into North Carolina as the upper shortwave trough
to the north also spills south and perhaps a weak wave develops.
Although this may be overdone, plan to keep going overall higher
chance pops in place with likelys in spots across southern/eastern
sections into the evening, and little pop remaining behind the
front across the far northwest. 850 mb boundary should finally
push south across the region overnight as the wave aloft slides
through allowing for a more easterly trajectory to take shape.
This may actually tend to hold in some low clouds over the south
and west with residual showers possible mainly southern half
through early Thursday. Otherwise clearing and cooler north/west
with more clouds under higher dewpoints lingering south. Lows
58-64 northwest to mid/upper 60s south and east.
Weak high pressure to build north of the region Thursday as the front
settles to the south. Models suggest plenty of drying aloft with only
southern sections holding onto higher dewpoints as the flow turns more
easterly. This should allow things to mix out from north to south as
heating gets going Thursday with perhaps clouds lingering southern Blue
Ridge sections a bit longer. Latest guidance also showing some
instability over the far southern and southwest sections where most
solutions insist on added convection mainly NC mountains Thursday
afternoon. This where a more southeast upslope component will develop
beneath some pooling of low level moisture per latest forecast
soundings. Since supported by the latest SREF will keep pops for a few
southwestern counties, but not go as wet as the GFS in lingering
showers southeast into the afternoon where a punch of better drying
looks to take shape. Should be a bit cooler and less humid with highs
mostly low/mid 80s with 70s at elevation pending the degree of
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 315 PM EDT Wednesday...
Ridge of high pressure will extend from Halifax/New Brunswick area
of eastern Canada southwest into the Blacksburg forecast area
through much of the short term period - supporting near normal
temperatures and dry conditions for most areas.
Exception will be across the NW NC mountains into the Grayson
Highlands of SW VA, where combination of upsloping easterly flow on
the periphery of the high pressure to the NE and a slightly
moister/richer Theta-E airmass will exist. This combination will
support the development of mainly diurnally-driven mid-afternoon
into early evening isolated to widely scattered showers or
thunderstorms. Given the isolated nature of any storms that develop,
even across the high country, many areas throughout the entire short-
term period will remain dry rather than wet.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 315 PM EDT Wednesday...
Slightly warmer temperatures along with a slowly increasing threat
for showers and thunderstorms, both temporally and spatially, is
expected during the long-term period as surface high pressure moves
away from the mid-Atlantic region - allowing surface winds to
gradually veer into more of a south to southwesterly component.
Longer range models reflect a series of weak, but randomly spaced
and difficult to time short waves embedded in westerly flow aloft -
each of which will support development of widely scattered to
scatted showers/storms maximized during and near time of peak
Although threat for convective activity will exist just about
anywhere in the Blacksburg forecast area, a somewhat higher threat
will be maintained in the mountains due to upsloping flow across the
western flanks of the Appalachians coupled with better differential
heating due to local topographical influences.
By late in the forecast period, specifically in the late Tuesday
night into Wednesday timeframe, the GFS model is rather bullish in
driving a cool front southeast into or through the mid-Atlantic
region, whereas the ECMWF washes this feature out and waits for a
better reinforcing shot of cooler/drier air which arrives after this
forecast period (Thursday into Friday). At the present time, the
ECMWF solution is preferred considering the tendency of cool fronts
having a hard time maintaining their integrity this time of year
this far south in a nearly zonal flow - with the more aggressive
models often backing away/slowing the timing of such arrivals a day
or two as the event nears.
Regardless, sufficient pre-frontal clouds and lack of strong high
pressure aloft will hold temperatures to only a few degrees above
normal - and certainly no where close to record readings.
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
As of 753 PM EDT Wednesday...
Isolated to widely scattered thunderstorms continue to rumble
eastward mainly across Southside VA into the Piedmont of NC,
affecting Danville TAF. Thunderstorms should continue in this
area until around 02z with isolated showers still possible until
midnight in this area as surface cold front sags southeast. TAFs
otherwise are VFR and will remain so through at least midnight.
Later in the overnight, high pressure ridges down the Blue Ridge
and will induce more of a light northeast/east wind across the
airspace. Potential exists for overnight fog in the western
river valleys but presence of at least light northeast/east
winds around 4-6 kts may preclude visbys worse than MVFR. May
also see MVFR stratus develop at Danville late in the overnight
as indicated by some forecast guidance with the easterly flow.
Confidence for overnight is low to moderate.
Should see variably cloudy skies greatest further south for
Thursday. Potential for lingering MVFR stratus in NC and up
into Danville but this should erode to a VFR cu/stratocu field
by early afternoon. Northeast to east winds 5-8 kts Thursday.
Confidence in the TAF is overall moderate, though is low to
moderate for the overnight period.
High pressure will return with VFR conditions Friday through
Saturday before moisture increases ahead of the next upstream
cold front by early next week. This may allow for isolated
convection, including localized restrictions to ceilings and
visibilities, to become more widespread especially mountains by
Monday afternoon. However confidence is too low to pinpoint
where the showers and thunderstorms may occur.
As of 1030 PM EDT Wednesday...
The NOAA weather radio transmitter in Hinton, West Virginia,
WXM72 broadcasting on a frequency of 162.425 MHz, remains off
the air. The local telephone company will need to replace an
audio circuit, and this work is expected to be completed
Thursday July 12th. We apologize for any inconvenience.
Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
953 PM CDT Wed Jul 11 2018
Most of the convection has dissipated this evening, although one
area of showers and storms persists over Northeast Louisiana, and
this activity may affect portions of North Central Louisiana and
Southern Arkansas over the next couple of hours. Some of the
models suggest some very isolated convection may redevelop after
midnight south of Interstate 20 as a weak mid level trough moves
westward across Southern Louisiana. The HRRR is particularly
aggressive with this scenario, but this is likely convective
feedback in the model. However, slight chance PoPs will be
maintained across portions of Louisiana and East Texas south of
I-20 through the remainder of tonight.
Overall, the forecast looks to be on track, and no updates are
.PREV DISCUSSION... /issued 704 PM CDT Wed Jul 11 2018/
For the 12/00z TAFs, scattered strong and isolated severe
convection will persist for several hours during the beginning of
the period. Convective coverage should slowly decrease through
the evening, but some of the model guidance suggest a few storms
may linger through the nighttime hours across Deep East Texas and
into Central Louisiana. The storms may lead to localized MVFR or
IFR flight conditions, but VFR conditions should generally
prevail. More scattered convection is likely across the entire
area after 12/16z.
PREV DISCUSSION... /issued 405 PM CDT Wed Jul 11 2018/
SHORT TERM.../Tonight through Thursday Night/
The combination of upper level disturbances and a weak shear axis
has resulted in a more active day of convection across much of
the region compared to the past few days. Outflow boundaries
generated from earlier convection today have led to additional
showers and thunderstorms developing with the process repeating
itself all afternoon. Expect this trend to gradually decrease with
the loss of heating, but weak upper level impulses may continue
to help trigger isolated convection tonight into early Thursday
morning so have not completely ruled out POPs through overnight
period. Low temperatures will fall back toward the mid 70s for
Thursday morning as cloud cover should linger through much of
A similar scenario will take shape on Thursday with the center of
the upper level ridge axis still poised to our north. Disturbances
tracking along and underneath the ridge will keep a decent chance
of showers and thunderstorms going into Thursday afternoon through
the early evening. Temperatures are also expected to run similarly
to today with upper 80s to lower 90s before we begin to heat up
heading into this weekend with the upper level ridge axis inching
closer to the region.
LONG TERM.../Friday through Tuesday Night/
Upper-level ridge of high pressure to become better established
across the region on Friday and remain dominant through the weekend
into the early part of the workweek. High temperatures are forecast
to steadily climb from the lower 90s on Friday to the mid to upper
90s by Tuesday.
Diurnally driven scattered showers and thunderstorms expected
areawide through the early part of the weekend. A weak upper-level
trough across the mid-Mississippi Valley on the northeastern
periphery of the ridge to allow for scattered to numerous showers
and thunderstorms mainly across south-central Arkansas and northeast
Louisiana from Sunday through Tuesday afternoons.
.PRELIMINARY POINT TEMPS/POPS...
SHV 75 92 76 95 / 30 50 20 30
MLU 75 93 75 94 / 30 50 20 30
DEQ 73 93 73 93 / 20 40 20 30
TXK 74 90 75 93 / 30 40 20 30
ELD 74 92 74 94 / 30 40 20 30
TYR 75 89 75 92 / 20 50 20 30
GGG 74 91 75 93 / 30 50 20 30
LFK 75 89 74 93 / 30 60 20 40
Area Forecast Discussion
National Weather Service Tucson AZ
820 PM MST Wed Jul 11 2018
.SYNOPSIS...Abundant monsoon moisture will remain in place across
southeast Arizona and lead to daily rounds of showers and
thunderstorms into this weekend. Some of the thunderstorms will
produce heavy rains and strong winds. Cooler than average daytime
temperatures will also continue due to the cloud cover and showers.
.DISCUSSION...Recent trends and the latest HRRR solution suggested
that the threat of heavy rainfall had greatly diminished. Thus, the
Flash Flood Watch has been cancelled for tonight. That said, updated
the forecast to reflect these trends in the short term. Otherwise,
the current forecast looked on track for tomorrow into the weekend.
Please refer to the additional sections for more details.
.AVIATION...Valid through 13/06Z.
ISOLD -TSRA/-SHRA with BKN080-120 cigs likely at all sites through
late Thursday morning. Outside of thunderstorms, expect normal
diurnal patterns. Aviation discussion not updated for TAF amendments.
.FIRE WEATHER...Abundant moisture will continue to aid the
development of isolated to scattered thunderstorms through the
forecast period. No significantly breezy days are expected at this
time, as 20-ft winds remaining below 15 mph aside from gusty
outflows around thunderstorm activity.
.PREV DISCUSSION...As usual tomorrow`s forecast hinges on how today
plays out, although it`s worth noting that the mid level flow turns
around out of the west/southwest during the day Thursday. Normally
this would be an unfavorable/drying flow and that will indeed be the
case, but with near record PWATS in place today this drying will
likely only knock values back down to where they should be for mid
July vs drying us out completely to the point we don`t see storms.
For that reason I left elevated PoPs in place for tomorrow. Storms
certainly appear likely, but perhaps with less areal coverage than
we`ve seen lately. Low confidence on exactly how Friday will
develop. Drying flow will remain in place but not to the point where
storms are absent from the area completely.
The forecast through the weekend into early next week depicts
relatively favorable flow aloft and above normal moisture. Day to
day storm chances will favor climatology with near to slightly below
normal temperatures. No major changes to the inherited forecast.
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Area Forecast Discussion
National Weather Service Las Vegas NV
349 PM PDT Wed Jul 11 2018
.SYNOPSIS...Plentiful moisture will remain in place through the
upcoming weekend resulting in daily chances for showers and
thunderstorms. Best chances for storm activity tonight will be
across southern Mohave and San Bernardino counties as well as across
Clark and Lincoln County. For the coming days the best chances for
storms will be across the high terrain with the lower Mojave Desert
beginning to gradually dry and warm late this week into the weekend.
Heavy rainfall and gusty winds will be possible with storms.
.SHORT TERM...Active afternoon so will be brief. Numerous
thunderstorms across southeast California and southern Mohave county
producing heavy rain within the Flash Flood Watch area. Watch will
continue into the evening with no plan of expanding at this time.
Elsewhere, coverage of thunderstorms more isolated to scattered
across south central Nevada and northern Mohave County. Coverage and
intensity of storms will diminish during the overnight hours with
models suggesting showers or weak thunderstorms drifting southwest
out of Lincoln County/northwest Mohave County into Clark county late
evening and overnight. HRRR indicates possible MCV developing over
Clark county after midnight. Storms should initiate early on the
higher terrain once again Thursday with hi-resolutions solutions
clustered together suggesting the potential of some type of broken
line or cluster of storms moving southeast out of Lincoln/central
Nye counties into southern Nye and Clark counties Thursday evening.
LONG TERM...Friday and beyond
High pressure begins to shift overhead
and broaden through the period. Moisture will remain in place, but a
lack of significant forcing and the shifting high will result in a
downward trend in convection over the lower Mojave Desert and
diurnal terrain-driven storms to the north. Temperatures will also
rise, though at this time it appears that temperatures will remain
below excessive heat levels. It will continue to feel somewhat muggy
by desert standards into next week.
.AVIATION...For McCarran...Isolated to scattered thunderstorms
within all approach corridors looks to dissipate early this evening.
After a quite evening some rain showers may move into the valley
from the northeast during the late evening and overnight hours.
Confidence low so will only mention as a VCSH now. On Thursday,
storms will develop over the higher terrain and not impact the
valley until late afternoon or hold off until the evening hours.
Outside of storms, winds will generally favor a southerly direction
at 10 kts or less.
For the rest of southern Nevada, northwest Arizona and southeast
California...Coverage of showers and thunderstorms will start
decreasing early this evening, only to redevelop primarily over the
higher terrain Thursday. With storms that develop, erratic, gusty
winds and locally heavy downpours will be likely along with periods
of lower cigs between 6k-9k feet. Outside of storm activity, winds
will favor the southerly direction between 10-15 knots with
intermittent gusts to around 20 knots possible this afternoon into
this evening before winds decrease overnight. &&
.SPOTTER INFORMATION STATEMENT...There will be chances for
thunderstorms each day through next week. Spotter activation may be
needed at times. Regardless of activation, spotters are encouraged
to report any significant weather or impacts according to standard
For more forecast information...see us on our webpage:
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