Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/02/18
Area Forecast Discussion
National Weather Service Bismarck ND
930 PM CDT Wed Aug 1 2018
.UPDATE...
Issued at 920 PM CDT Wed Aug 1 2018
Made a few minor adjustments to sky cover with some high level
clouds traversing the forecast area tonight. Lowered temperatures
just a bit over eastern portions of the forecast area, closer to
the center of the high over the eastern Dakotas and Minnesota.
UPDATE Issued at 620 PM CDT Wed Aug 1 2018
No major changes with the 600 PM update besides blending in
observations. Made minor adjustments to sky grids to account for
diurnal cumulus sticking around the central for the next couple
hours.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 247 PM CDT Wed Aug 1 2018
Very warm temperatures west on Thursday highlights the short term
forecast.
A surface high pressure ridge axis across the Northern Plains this
afternoon will propagate into the Upper Mississippi Valley on
Thursday, with return flow across the Northern Plains ahead of low
pressure across eastern Montana. Trended towards the warmer edge
of the 12 UTC global suite of guidance for high temperatures on
Thursday, especially along and west of US Highway 83 behind the
surface warm front. Vegetation continues to slowly cure promoting
more efficient surface heating, with a dry airmass and deep
mixing also supporting greater heating potential. High
temperatures in the mid to upper 90s are favored across the far
west, with lower 90s across the central through US Highway 83.
The HRRR experimental near surface smoke guidance also suggests
the potential for increasing concentrations across the far
southwest as smoke from western US wildfires is transported east.
.LONG TERM...(Thursday night through Wednesday)
Issued at 247 PM CDT Wed Aug 1 2018
A very warm Friday with a Marginal Risk for severe thunderstorms
highlights the extended forecast.
Widespread highs in the 90s are forecast across most of western
and central North Dakota on Friday in the warm sector of the
surface low across southern Canada/far northern North Dakota.
Again, followed closer to the warmer edge of the 12 UTC global
suite per similar reasoning as outlined in the short term
forecast. A few 100 degree readings are not out of the question,
especially across the south central. SPC has central North Dakota
in a Marginal Risk for severe thunderstorms in their Day 3
outlook. Moderate MLCAPE values with surface dewpoints in the
60s, and deep layer shear around 30 kts supports the potential for
at least a Marginal Risk for severe thunderstorms east of US
Highway 83 ahead of an occluding front. However, capping does
appear to be somewhat of a source of uncertainty given the warm
airmass.
Will also have to monitor possible smoke impacts for Friday behind
the front.
Near zonal upper level flow for the weekend supports sporadic
convective chances across western and central North Dakota with
near normal temperatures in the 80s. An upper level ridge may
build across the region mid to late next week, supporting a
possibly prolonged period of above normal temperatures as
supported by the CPC outlooks and CIPS analogs.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 920 PM CDT Wed Aug 1 2018
Scattered stratocumulus is forecast to redevelop in areas of the
James River Valley by 13Z. Thinking at this time is layer will
remain scattered and lift fairly quickly so for now no MVFR layer.
Otherwise VFR conditions expected elsewhere across western and
central North Dakota. Winds turn southerly in the morning hours at
all terminals.
&&
.FIRE WEATHER...
Issued at 247 PM CDT Wed Aug 1 2018
High temperatures in the mid to upper 90s are expected across
western North Dakota on Thursday, generally along and west of US
Highway 85, with afternoon minimum relative humidity of 15 to 20
percent. Across central North Dakota, high temperatures will range
from the lower 90s across the US Highway 83 corridor, to the 80s
from the Turtle Mountains through the James River Valley. Relative
humidity is expected to range from 30 to 40 percent for these
areas. South to southwest winds of 15 to 20 mph are expected west
and central.
For Friday, widespread high temperatures in the 90s are forecast across
most of western and central North Dakota. Relative humidity
around 20 percent is expected generally along and west of US
Highway 83, with higher values to the east. Southerly winds
around 10 mph are forecast central, with westerly winds around
10-15 mph across the west.
Given marginal winds, and feedback that fuels need around one to
two weeks of additional curing to support rapid fire growth, fire
weather headlines are not anticipated at this time.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...PA
LONG TERM...PA
AVIATION...TWH
FIRE WEATHER...PA
Area Forecast Discussion
National Weather Service Dodge City KS
613 PM CDT Wed Aug 1 2018
...Updated aviation discussion...
.SHORT TERM...(This evening through Thursday)
Issued at 237 PM CDT Wed Aug 1 2018
Mid level northwest flow remains anchored over the High Plains region,
as surface high pressure is advancing farther south and east into
the Mississippi valley. Enough of a surface pressure gradient has
developed to allow a few locations to see south winds above 10 knots
this afternoon across west central KS. Late day thunderstorms
develop over central CO is expected to dive southeast with time late
today and this evening. Chances for thunderstorms affecting our
southwest counties is low, however he HRRR has been consistent with
a few convective elements near Elkhart toward midnight.
For Thursday, the upper ridge becomes positively tilted eastward,
raising thickness and the mean heights across western KS. South
winds should be closer to normal wind speeds again however a
significant warmup is in question given a lack of downslope
component and a persistently negative 850 mb temperature tendency
in the NAM 12km model. The models are actually indicating a large
variance for forecast highs on Thursday afternoon, anywhere form
mid/upper 80s on ECMWF to mid 90s in HiRes solutions.
.LONG TERM...(Thursday night through Wednesday)
Issued at 237 PM CDT Wed Aug 1 2018
There is a good degree of increasing confidence for rain and
thunderstorms in the the Friday night timeframe. The ECMWF/GFS as NAM
all show an elongated region of rain/thunderstorms associated with a
deeper plume of subtropical moisture Friday night, extending from
the desert southwest into the northern plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 613 PM CDT Wed Aug 1 2018
VFR conditions should prevail through this period. Widely
scattered thunderstorms developing off the Colorado Front Range
will clip southwest Kansas later this evening. Expect that these
storms will remain west of Liberal but will continue to monitor
trends. Deepening surface pressure in the lee of the northern and
central Rockies on Thursday will bring increasing southerly winds
to the terminals with gusts to 25 knots possible by midday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 61 91 68 93 / 10 0 0 0
GCK 61 91 66 94 / 10 0 0 10
EHA 61 93 67 95 / 20 0 0 10
LBL 62 92 67 95 / 20 0 0 10
HYS 63 92 68 93 / 10 0 0 0
P28 64 93 68 94 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Gerard
Area Forecast Discussion
National Weather Service Des Moines IA
640 PM CDT Wed Aug 1 2018
.DISCUSSION.../Tonight through Wednesday/
Issued at 343 PM CDT Wed Aug 1 2018
Relatively quiet weather continues throughout much of the
forecast with a few isolated storms still possible this afternoon
into the evening with the cold frontal passage. Otherwise, the
focus of the forecast was on the heat building back into the
region and a periodic storm chances over the weekend into early
next week.
Cold front slowly creeping into northwest Iowa late this afternoon
will continue progress southeast this evening. The latest hires
models, especially the HRRR and ESRL HRRR, have the best handle on
the current radar trends and depictions through late this
evening. There is limited instability due to the weak shower/cloud
cover from southwest to northeast Iowa through the day and shear
remains low or even non existence. Not much going for severe
weather chances later this afternoon into the evening, but still
cannot rule out an isolated threat for now.
Surface high pressure builds into the state tonight into Thursday
providing cool and dry conditions. This high shifts east through
the day Friday and return flow begins to develop from west to
east across the forecast area. The ECMWF is a bit stronger and
faster with a shortwave to cut across the region late Saturday
into Saturday evening. Certainly looks to be a breezy and warm day
Saturday and confident to nudge up wind gusts a couple of knots.
Winds near the mix layer range from 28-36 knots but with forecast
soundings suggesting some high clouds, this should limited some of
the deep mixing. Regardless, the surface pressure gradient
increases and mixing is likely to be enough for wind gusts around
25 mph or slightly higher Saturday afternoon. 850mb temperatures
still progged to range from +20C to +22C Saturday afternoon and
Sunday afternoon, and thus warm temperatures on track for the
weekend. Surface dew points remain in the lower to middle 60s and
not anticipating significant heat index values over the weekend.
Sunday night into Monday, the ECMWF and GFS are in decent
agreement with another shortwave riding the westerly flow into
the region. Timing and location looks to be b/t 00-12z Monday and
over central to northern Iowa. Severe potential remains uncertain,
but instability increases Sunday afternoon there is decent shear
present Sunday night into Monday. Certainly something to continue
to monitor if models continue to converge on timing and location.
&&
.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 640 PM CDT Wed Aug 1 2018
Storms have developed along a passing cold front as expected. The
front will pass southeast across the TAF locations through 06Z-07Z.
MVFR cigs/vsbys associated with FROPA and storms then again late
tonight with a potential for some patchy fog otherwise VFR
conditions will prevail. Ahead of the front southerly winds at 5-
15kts are forecast. Behind the front, winds become northwest at
15g25kts and these are expected to become lighter further behind the
front...aft 06Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
DISCUSSION...Podrazik
AVIATION...FAB
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
628 PM CDT Wed Aug 1 2018
.Discussion...
Issued at 217 PM CDT WED AUG 1 2018
Quiet wx pattern persisting over the region this afternoon as a
sfc ridge of high pressure extends northeast from the southern
Plains. Main item of interest heading into the overnight hours
will be a weak frontal boundary that will sag south into northern
Missouri during the predawn hours, along with isolated shwr/storm
chances. For now, available high-res guidance to include the
NAMNest and HRRR show minimal activity towards daybreak, which
makes sense given weak frontal coverage and modest upper-level
support for ascent. That said, deterministic models to include
both the NAM and GFS continue to highlight a swath of light QPF
along the boundary, so felt best to maintain an isolated mention
after 06z for areas mainly north of Route 36. Any developing
activity should have little impact in response to weak wind fields
aloft which should keep any severe development in check. Lows
tonight should be a similar to this morning`s with low to mid 60s
expected.
Main story heading into the weekend will be a continued warming
trend as the upper ridge over the Four Corners region begins to
slide east with time. Heights downstream over the lwr Missouri
Valley start building as early as tomorrow with southerly low-
level winds likely supporting highs in the upper 80s to lower 90s.
The only caveat seen this afternoon with tomorrow`s high temp
forecast may be possible midlevel cloud cover associated with the
cold front which may tamper daytime heating to some degree across
the far north. Unfortunately the warming trend will continue
right through the weekend and into early portions of next week,
with Monday and Tuesday both looking to be the most impactful as
dewpoints again warm into the upper 60s to lower 70s. These values
along with afternoon highs in the low to mid 90s will support
dangerous heat indices once again, and future shifts may need to
consider heat related headlines as the timing nears. In term of
precip potential, there`s some hint in today`s model runs that a
cold front will weaken as it approaches from the central Plains on
Saturday, and the GFS and NAM both show light QPF extending as
far east as our western counties late Saturday afternoon and
overnight. Another chance for rain may arrive Monday evening and
Tuesday as another cold front sags south and possibly stalls over
the region. Latest GFS solution shows a fairly healthy QPF
footprint over our area, but details such as frontal positioning
and model convective feedback issues need to be resolved before we
can get too excited.
&&
.Aviation...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 626 PM CDT WED AUG 1 2018
VFR conditions are expected to prevail through the period. Winds
will remain relatively light and out of the west and southwest.
some mid to high clouds will exist at various times through the
period.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Discussion...32
Aviation...Kurtz
Area Forecast Discussion
National Weather Service Grand Junction CO
325 PM MDT Wed Aug 1 2018
.SHORT TERM...(Tonight through Thursday night)
Issued at 325 PM MDT Wed Aug 1 2018
Current mesoanalysis is depicting very weak CAPE over SW Colorado
and NE Utah with Precipitable Water (PW) values between 0.5 and
0.6 inches across these areas. The deeper moisture is still
hanging out in the Desert Southwest extending as far north and
east as southwest Utah. This is evident in the trends so far
today. Persistent mid and high level cloud cover this morning
across much of the region has inhibited convective development
with some virga showers present underneath across much of the
area. This has also kept our temperatures down and chances of
reaching our previously forecasted high temperatures appears slim,
so adjusted the max temps and PoPs down accordingly. The
exception to this is areas on the edge of the cloud shield and
where the sun has allowed for more surface heating. Storms
developed over the San Juans along the southern fringes of the
ridges and across eastern Uintas. There has been frequent
lightning with the San Juan storms, but mostly in cloud and some
light to moderate rain. However, low levels still remain fairly
dry today with RH in the teens for the most part with a few
exceptions, in areas of showers where the RH is in the 20s. As
cloud cover spreads further south in this northwesterly flow,
anticipating some stabilization which will inhibit cumulus
growth late this afternoon into the evening and put convection to
bed for the night after the sun sets. Already seeing this trend
occurring as storms down south are having a tough time sustaining
themselves as they shift further south off the terrain.
On the other hand, plenty of smoke is hanging around as it was
trapped under inversions overnight and the persistent cloud cover
has allowed these inversions to persist across much of the area,
keeping the smoke fairly stagnant. The smoke is being transported
from the wildfires in California clockwise around the area of high
pressure, situated to our southwest over Arizona, and into our
CWA. Smoke from local wildfires burning across western Colorado is
not helping matters as these areas downstream to the south and
southeast of the fires are seeing worse conditions due to smoke.
The latest HRRR model is showing this smoke persisting through at
least Thursday night, so adjusted the forecast to reflect this.
The forecast models seem to have backed off somewhat on the next
moisture push. A trough of low pressure moves in over the Pacific
NW and suppresses this ridge of high pressure southward, causing
it to also elongate. This shifts our flow to a more westerly flow
Thursday, which allows better moisture to arrive from the west. PW
values are projected to increase above 0.75 inches by Thursday
afternoon and above an inch by Thursday evening across portions of
the area, particularly eastern Utah and extreme western Colorado.
A shortwave will move through the northern and central portions
of the area Thursday evening, resulting in an increase in shower
and thunderstorm activity. Due to the late arrival of the
shortwave and better moisture, the model QPF follows suit and
indicates a later start to convection by late afternoon. There is
also a good chance of nocturnal convection lasting overnight with
the passing shortwave. Gusty outflow winds and frequent lightning
remain biggest concerns but the increase in moisture will also
lead to better chances of brief moderate to heavy rain. The models
have not been consistent with placement of showers and have
really backed off on QPF amounts, so am not confident enough to
hoist any Flash Flood Watch for the burn scar areas. Thinking this
may be more localized with storm activity more scattered in
coverage, with the bulk of activity happening late in the day.
.LONG TERM...(Friday through Wednesday)
Issued at 325 PM MDT Wed Aug 1 2018
The Pacific NW trough continues pushing across the northern
Rockies Friday, leading to continued increase in moisture from the
west. Expecting Friday to be the peak in any moisture and best
chances and coverage of thunderstorm activity. However, a big
concern is that when the shortwave disturbances move through in
the overnight periods, which is the case Thursday night into
Friday morning, there tends to be too much convective debris or
cloud cover in the morning that inhibits convection until much
later in the day. This looks to be the case Friday as the models
are showing a later start to convection once again. However,
better forcing and instability will be over the forecast area
Friday with our CWA in the left exit region of the upper level
jet. A more robust shortwave looks to move through Friday evening,
leading to a better increase in thunderstorm activity favoring the
evening and overnight periods. Built the PoP grids to reflect this
trend and it makes sense given the later start due to morning
cloud cover. Lowered max temps as well due to the increased clouds
and showers, but still kept them above normal. Friday also appears
the better day to see storms impacting the valleys late in the day
and a better chance of heavy rain. Flash flooding potential over
recent burn scars will have to be monitored as well as trends in
model QPF, but models do appear to have backed off in the PoP
department, so not as confident yet to issue any watches.
Drier air moves back in by Saturday for a downturn in convection.
Still enough moisture looks to be recycled under the high to
result in afternoon storms mainly over the higher terrain. The
high makes a subtle shift eastward by Sunday, with a southwest
flow developing, allowing for an increase in moisture and storm
potential. Confidence though is not as high for Sunday as the
models have not been consistent with this trend. The models are
coming into better agreement though on the westward shift of the
high pressure by early next week and the ridge building strong,
allowing much drier air to encompass the region from the north,
leading to a downturn in storm activity for next week and a
resultant warming of daytime temperatures.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1128 AM MDT Wed Aug 1 2018
Smoky...hazy conditions will continue over the next 24 hours with
very active local and national fires. VFR conditions should be the
prevailing conditions but can not rule out MVFR pockets where
smoke is thicker closer to fires. Virga moving through on radar
mosaic this AM and this will generally lead to a slight uptick in
afternoon thunderstorm activity, but confidence extremely low on
where so no mention in TAFs attm.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...MDA
LONG TERM...MDA
AVIATION...TGJT
Area Forecast Discussion
National Weather Service Wilmington NC
943 PM EDT Wed Aug 1 2018
.SYNOPSIS...
Deep tropical moisture will shift inland through mid-week as a ridge
builds westward from the Atlantic. This will push the most active
weather farther inland with a return to more localized shower and
thunderstorms, especially along the coast. The trend toward more
localized thunderstorm activity will continue into early next week
as high pressure takes residence over the Carolinas.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 945 PM Wednesday...convection has waned in the past half
hour but isolated showers are possible throughout the night.
The 00 UTC HRRR indicated possible showers along the coast
mainly north of Little River. Also, the 00 UTC nam is showing
convection moving Georgetown and Horry counties just before
daybreak and shifting northward.
Previous Discussion...Not much change expected to the
synoptic pattern through Thursday. The mid and upper-level
trough centered over the Mississippi River will remain, but
begin to fill. Off the coast, a ridge will persist surface-
aloft, with a weak mid/upper low circulating around its southern
periphery. Shower and thunderstorm activity should diminish
late this evening, then better chances developing across the
coastal counties after midnight as marine activity migrates
onshore. This should lead into scattered convection over the
eastern 1/3 of the forecast area in the 12-16Z time frame
Thursday, with the focus shifting inland after noon. Also,
precipitable water values will increase slightly by Thursday,
exceeding 2" across most of the forecast area. This may lend to
greater coverage of showers and thunderstorms than we are seeing
this afternoon, with locally heavy downpours.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 230 PM Wednesday...Deep layer southerly flow continues through
the period as large high pressure sits offshore both surface and
aloft while mid level trough remains to our west. Deep moisture
within this flow had been pushed to our west but there will be a
small shift back eastward as some mid level energy ejects out of the
trough to our west-most pronounced early in the period. Forecast
soundings show PW values surging back above 2 inches. Later on
Friday and into Friday night as a large shortwave moves off to the
northeast around the Atlantic High the ridge itself begins to assert
itself back into the Carolinas. Daytime temps still a few degrees
below climatology as cloud cover may be fairly widespread. The
convection-inhibiting inversion formed by the ridge looks too weak
and too late in the day Friday to be very effective and the
afternoon appears quite unsettled. With the loss of heating and the
continued westward push of the upper ridge Friday night will see a
considerable decrease in radar coverage.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 230 PM Wednesday...The center of a mid/upper level ridge will
build westward from the adjacent Atlantic waters across NC this
weekend. The ridge will preside across the Carolinas Monday before
drifting southward across FL and the northeast Gulf of Mexico
Tuesday as a mid/upper trough attempts to become established across
the eastern United States. Surface high pressure will ridge in from
the east as well, while weak inland troughing develops. There will
be some weak lift from the sea breeze each day, as well as the
inland trough however the precipitable water will lower to 1.8
inches or less from the latter half of Saturday through Tuesday.
Thus, not expecting much in the way of areal coverage with any
storms during the extended, other than typical diurnal activity. As
heights increase with the building ridge aloft high temperatures
will increase through the first part of next week, likely getting a
few degrees above climatology Sunday and Monday.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
As of 00Z...Scattered showers continue streaming across the area
and have a 50% chance of impacting the TAF sites for a brief
time as the cells are moving to the north-northeast at 15 to 20
knots. Expect mainly VFR conditions with possible MVFR
conditions if a show does move of the airports. Also, the is
chance to see MVFR conditions from BR generally after 08 UTC.
IFR ceilings are possible after 08 UTC mainly at KFLO but
confidence is not high so went with scattered deck around 700
feet.
Extended Outlook...MVFR/IFR from scattered to numerous SHRA/TSRA
each afternoon and evening across all sites through Friday.
Lesser chances for showers and storms over the weekend.
&&
.MARINE...
NEAR TERM /THROUGH THURSDAY/...
As of 945 PM Wednesday...Surface high pressure will continue
with a southerly flow of 15 knots. Seas will range from 2 to 4
feet. Isolated showers and thunderstorms embedded within the
moist and unstable tropical flow should become a little more
numerous after midnight.
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 230 PM Wednesday...Little change on surface weather maps
through the period as a large area of high pressure sits nearly
stationary across much of the western Atlantic. Wind will remain in
the 10-15kt range out of the south much of the time and with
stronger flow aloft gusts to 20kt should be quite common. Seas will
average 3-4 ft.
LONG TERM /SATURDAY THROUGH MONDAY/...
As of 230 PM Wednesday...Surface high pressure just east of the
waters will help to maintain southerly flow Saturday and Sunday.
The ridge will building south and weaken during Monday with
southwest to west flow possible late in the period. Seas 3 ft or
less through the period with only isolated to widely scattered
convection possible, especially overnight into the early
morning this weekend.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Beach Hazards Statement from 6 AM EDT Thursday through
Thursday evening for SCZ054-056.
NC...Beach Hazards Statement from 6 AM EDT Thursday through
Thursday evening for NCZ106-108.
MARINE...None.
&&
$$
NEAR TERM...RH/CRM
SHORT TERM...MBB
LONG TERM...SRP
AVIATION...RH
Area Forecast Discussion
National Weather Service Pocatello ID
236 PM MDT Wed Aug 1 2018
.DISCUSSION...Today Through Next Wednesday.
We continue to monitor multiple weather hazards today.
CRITICAL FIRE WEATHER: Red Flag Warnings remain in effect until 9 PM
this eve for large portions of the forecast area due to expected scattered
t-storms. Frequent lightning and strong t-storm winds in excess
of 50 MPH will be the greatest fire-weather related hazards. In
addition, while the strongest cells may produce heavy downpours,
continued dry air at the surface will evaporate some of the rain
as it falls and will likely keep precip amounts light at most
locations. See the FIRE WEATHER section below for more details.
STRONG THUNDERSTORMS: T-storms are just starting to develop across
the Central Mntns and along the MT border. We once again used the
HREF ensemble CAMs as a general guide for t-storm coverage and
placement today, but these models had decent support from the
NAM12, RAP, and HRRR as well. We increased PoPs yet again in two
favored corridors for convection: the Central Mntns and and
northeast CWA north of a line from Ketchum, to Arco, to Rexburg,
to Driggs, and across the Southern Highlands and Bear Lake region,
where at least scattered t-storm coverage is expected. Isolated
t-storms will still be possible in between these two zones. NAM
forecast soundings this afternoon continue to display inverted-V
soundings featuring dry air in the low-levels, LCLs at or just
above the melting layer, and DCAPE values of 1,000 to 1,500 J/kg,
indicating the potential for strong downdraft/outflow winds
potentially in excess of 50 MPH with the stronger cells.
Instability is somewhat skinny up in the hail growth zone, and
overall shear and MUCAPE values do not favor very large hail, but
with PWATs increasing to 0.75 to 0.95 inches, could see a few
heavy downpours and at least some small hail with the most robust
updrafts. Frequent lightning is expected as well.
MORE HEAT: Projected temperatures once again bring us very close
to Heat Advisory criteria this afternoon across the Lower Snake
Plain, eastern Magic Valley, and Southern Highlands, with rather
marginal relief tonight as lows may only drop into the upper 60s
in some areas. However, real estate reaching advisory criteria
encompass less than half of any given forecast zone, and any
clouds and showers/t-storms this afternoon will bring localized
relief from the hot temperatures. Thus, we will not be issuing an
advisory this afternoon. Those who are working or recreating
outdoors or are otherwise sensitive to the heat will want to take
precautions, however, including frequent breaks in the shade or
air conditioning and continuous hydration. High temps Thurs will
likely come in a few degrees cooler than today.
Another round of showers/t-storms are expected Thurs afternoon
and eve from Mackay, Blackfoot, American Falls, and Oakley
eastward. Breezy conditions are also expected during the afternoon
across the entire region. Friday will be drier but again breezy.
The combination of stronger winds and areas of low RH values may
bring portions of the region very close to critical fire weather
conditions again Thurs-Sat. Dry weather is currently on tap for
the weekend and next week for SE Idaho as we transition back into
a ridge of high pressure across the western US. - KSmith/TW
&&
.AVIATION...
Upper level high pressure ridge is moving east allowing moisture
to move into our area. Best chance of vicinity thunderstorms is at
KSUN, KIDA and KDIJ. Late afternoon development is possible at
KBYI and KPIH, but with lower confidence. Expect a Trace to around
0.05 inches of rain, but CIG/VIS probably remain VFR. Breezy
winds develop on Thursday, affecting all TAF sites in the
afternoon. Winds will be a little stronger on Friday. - TW
&&
.FIRE WEATHER...
Upper level high pressure ridge is moving east allowing moisture
to move into our area. Thunderstorms will likely produce a Trace
to 0.08 inch rain fall amounts for most areas, but still less than
a wetting rain. Red Flag Warning remains in effect until 9 pm MDT
for the Salmon-Challis NF, the Snake Plain, and the Southern
Sawtooth NF and Caribou NF areas. Thunderstorms remain a threat
for the Caribou-Targhee NF Thursday afternoon just before the
front comes through. Dry air will increase behind the front and
late afternoon winds will begin to increase. Zones 476 and 422
look like they will reach critical RH/Wind values at lower
elevations of 7000 and 6500 feet respectively. With warnings
already out, decided to hold off on additional statements at this
time. Strongest winds and lowest RH develops Fri, all of the
Central Mountains, Snake Plain, Southern Sawtooth look critical.
Parts of 413 below 5500 feet probably will as well. - TW/RS
&&
.CLIMATE...
A historic, long-duration heat wave continues today across SE Idaho.
Pocatello Airport (KPIH) continues to add to it`s all-time record
for longest streak of high temperatures at or above 90 that started
back on July 4th, now sitting at 29 consecutive days as of today.
Pocatello also ended the month of July in 10th Place for highest
mean average temperature at 73.5 degrees. Burley Airport (KBYI) is
sitting at 21 consecutive days at or above 90 as of today, now tied
for 3rd Place for longest streak since records began there in 1948.
Challis Airport (KLLJ) has also broken it`s all-time record for
longest streak at or above 90 since records began there all the
way back in 1895, reaching 27 consecutive days as of Tuesday
07/31/18. July 2018 was also the hottest July ever on record at
Challis for mean average temperature.
This heat wave has been historic in it`s persistence and duration,
but not necessarily for extreme values. Only a few days have
approached 100 degrees, and only 4 record high temps were tied or
set this month at our 6 climate sites. These streaks may be in
jeopardy at Challis today due to clouds, smoke, and a chance of
t-storms holding high temperatures in check, and by Fri or Sat at
Pocatello and Burley as slightly cooler air works into the region
behind a trough/weak front. Stay tuned. - KSmith/TW
&&
.AIR STAGNATION...
Degraded air quality is expected to continue across SE Idaho for
at least the next several days due to numerous wildfires burning
across the Pacific Northwest. The Idaho Department of
Environmental Quality (ID DEQ) currently rates air quality
"Moderate" or Yellow across the entire region, meaning that air
quality is acceptable, however, for some pollutants there may be a
moderate health concern for a very small number of people who are
unusually sensitive to air pollution. Localized periods of
"Unhealthy for Sensitive Groups" or Orange have also been
observed, particularly in the Central Mntns. In general, the
greatest smoke pooling will occur at night in valleys/lower
elevations, and this is when the greatest impacts may be noticed.
Have maintained areas of smoke in the weather grids for the entire
CWA through Fri morning. Some relief is possible thereafter as a
weak cold front ushers in stronger afternoon/eve winds across the
region, but transport of smoke from wildfires in CA, NV, and OR
may continue. - KSmith/TW
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT this evening for IDZ410-413-427-
475-476.
&&
$$
Area Forecast Discussion
National Weather Service Sacramento CA
329 PM PDT Wed Aug 1 2018
.SYNOPSIS...
Smoke will help to keep daytime temperatures cooler the next
couple of days. Cooling trend for the second half of the week into
the weekend.
&&
.DISCUSSION...
Latest satellite imagery shows areas of smoke and haze this
afternoon as several wildfires burn across northern CA. Afternoon
temperatures are running a few degrees cooler compared to
yesterday`s, with Valley highs in the upper 80s to 90s as of this
writing.
An upper system moving into the Pacific NW will weaken the upper
ridge, so temperatures will cool down through the rest of this
week. Onshore flow will bring additional cooling across the area on
Thursday. Valley temperatures over the next few days will
generally peak in the 90s, near 100 around Redding through Friday.
Temperatures cool a further on Saturday, a little below normal
levels.
A shortwave trough will approach the region late Friday into
Saturday, enhancing winds across the area. Local gusty north winds
will develop over western Shasta Co including the Carr fire
Thursday night and Friday, then gusty southwest ridge-top winds
expected on Saturday. Meanwhile, local west to southwest ridgetop
wind gusts to 30 mph are anticipated this Saturday. This could
result in locally critical fire weather conditions over the
Coastal Range. Therefore, a Fire Weather Watch is in effect near
the Carr Fire burn area from Thursday evening into Saturday
evening, and for very dry and gusty conditions over the Coastal
Range on Saturday.
Poor air quality remains across the area due to wildfire smoke.
Make sure to check local air quality reports. HRRR Smoke model
suggests that the Delta breeze may locally bring some cleaner air
through the Delta and into adjacent areas. In addition, smoke is
expected to clear out as the trough drops down.
No precipitation is expected across interior NorCal as monsoon
moisture will remain outside of the forecast period.
&&
.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)
Dry weather with a gradual cooling trend is expected Sunday into
Monday as upper level ridging is flattened at times by a series
of disturbances. Temperatures will drop to within a few degrees of
normal, with Valley highs in the 90s. Wildfire smoke could also
continue to impact visibility and air quality. Models were
previously suggesting that a deeper trough approaching the West
Coast next week could bring cooler temperatures. However, latest
guidance indicates that the upper ridge could rebuild and expand
northward, bringing warmer temperatures across interior NorCal.
Forecast confidence is low in the details so stay tuned.
&&
.AVIATION...
Local MVFR/IFR in smoke and haze across interior northern CA the
next 24 hours. Valley winds will primarily remain at 10 kt or
less, except SW gusts up to 25 kt near the Delta and over higher
terrain.
Dang
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Thursday evening through Saturday
evening for Eastern Mendocino NF-Eastern Portion of
Shasta/Trinity NF-Lake County Portion of Lake-Napa-Sonoma Unit-
Northern Sacramento Valley to Southern Tehama County Line Below
1000 Ft-Southeast Edge Shasta-Trinity NF and Western Portions of
Tehama-Glenn Unit.
&&
$$
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
741 PM EDT Wed Aug 1 2018
.UPDATE...
Latest RAP shows a mid level trough from Canada south...across the
Great Lakes...to the north-central Gulf coastal waters while a ridge
southeast of New England stretches over FL to the southeastern Gulf
waters. At the surface the Bermuda high reaches westward to the
Deep South and the eastern half of the Gulf with an axis near the
GA/SC border. These features maintain deep southerly and moist
flow overnight. Although there will be a subtle decrease in
moisture with PWAT values over 2 inches dropping down to around
1.9 inches by dawn.
The afternoon convection was well behaved with only a few reports
of gusts around 40 MPH. Most of the showers and storms have
tapered off as they exit the area. However a brief storm could pop
up during the next hour or so on an old outflow boundary. Will
adjust the forecasts to reflect the ongoing conditions and to end
showers/storms by 9 or 10 PM. The remainder of the night will see
debris cloudiness slowly clearing with light variable or south to
southeast winds.
&&
.AVIATION...
02/00Z TAFs. The bulk of the afternoon TSRA has pretty much left
the area. However can not rule out a rouge TSRA forming on a left
over outflow and will keep VCNTY remarks in TIL 03Z. Then VFR
overnight with light and mostly variable winds. The current
pattern continues into THU with TSRA from late morning through
the afternoon with increasing flow shifting from the SE to S-SW
keeping the higher odds of TSRA inland.
&&
.MARINE...
The subtropical ridge axis north of FL provides prevailing southerly
to southeasterly winds through the rest of the week. This ridge axis
lifts northward during the weekend with winds becoming easterly.
However seas breezes will result in an onshore shift near the coast
in the afternoons. Winds and seas remain benign expect locally
higher in and near thunderstorms.
&&
.Preliminary Point Temps/PoPs...
TPA 77 88 76 91 / 40 70 40 40
FMY 76 90 76 91 / 20 50 40 50
GIF 75 88 75 91 / 40 70 50 50
SRQ 77 87 76 90 / 40 50 40 40
BKV 74 87 74 91 / 30 70 50 40
SPG 78 88 77 91 / 40 60 40 40
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...Beach Hazards Statement through Thursday evening for
Coastal Charlotte-Coastal Lee-Coastal Sarasota.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...09/Rude
UPPER AIR...27/Shiveley
DECISION SUPPORT...84/Austin
Area Forecast Discussion
National Weather Service Tucson AZ
330 PM MST Wed Aug 1 2018
.SYNOPSIS...Shower and thunderstorm chances will increase across
the area this afternoon. A favorable pattern will keep rain chances
elevated into the weekend as deeper moisture moves into the region.
Temperatures will remain within a few degrees of normal for early
August.
&&
.DISCUSSION...High temperatures so far this afternoon are running 2-
6 degs higher compared to Tuesday at this time, with KTUS having
already hit 105 degs. Surface dewpoints however were down slightly
over the last 24 hours, anywhere from 2 to 7 degrees, likely due to
more complete mixing of the PBL. A scattered cu field was in place
for most of the region with storms starting to pop up mainly over
the higher terrain. Storm motions were pretty slow so far but toward
the west, with strong northerly winds shearing the anvils off toward
the south. In general though, satellite trends suggest a line of
storms organizing across the Mogollon Rim extending from northern AZ
southeastward into southwest NM. The CAMs including the latest HRRR
and U of A WRF models are in agreement with storms pushing west or
southwest off the Rim and into the valleys this evening. Blowing
dust remains in the forecast for much of southeast Pinal and
northern Pima Counties to account for the possibility of some strong
outflows. While it seems this may be the "main event" this
afternoon, other storms should be able form across the remaining sky
islands and move westward into the valleys. A few heavy downpours
will be possible with rainfall amounts around 1/2 inch and locally
higher accumulations. All in all though it should be a fairly
typical monsoon day with not much upper level support for organized
severe convection. We should be able to wrap things up rain-wise by
02/06Z this evening.
To close out the work week, high pressure remains quasi-stationary
which will result in typical monsoon conditions for early August.
The GFS brings a vort max through eastern areas on Thursday
afternoon which may result in a slight uptick in storm coverage.
Over the weekend, the ridge will flatten some with high pressure
reorienting off the southern California coast, before moving back
inland and settling across New Mexico early next week. This may
reduce rain chances for a day, but it doesn`t look to be a complete
shutdown by any means. The GFS and ECMWF solutions are pretty
similar with the migration pattern of the high, but the GFS is
currently the wetter of the two models, especially next week. As is
often the case this time of year, the timing and placement of each
day`s convection will be somewhat dependent on the previous day`s
activity.
High temperatures over the next week will generally hover within a
few degrees of average.
&&
..AVIATION...Valid through 03/00Z.
FEW to SCT clouds 8k-12k will increase in coverage through the
afternoon as SCT TSRA develops. Expected storm motion is toward the
southwest to west, with activity gradually diminishing after sunset.
Typical diurnal wind trends continue outside of potential gusty
thunderstorm outflow. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...Sufficient moisture typical of early August remains
in place through the forecast, with daily afternoon/evening
thunderstorms continuing. Humidities will recover well each night
and only drop to around 20-30 percent each afternoon. Outside of
thunderstorm induced gusts, expect diurnal trends with speeds of 15
mph or less.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Carpenter/Howlett
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
500 PM MDT Wed Aug 1 2018
.DISCUSSION...(This Evening Through Wednesday)
Issued at 222 PM MDT Wed Aug 1 2018
An upper ridge persists over the western CONUS, with a trough
over the east. Low clouds have dissipated across the much of the
western SD plains, leaving skies partly cloudy. Satellite shows
some smoke drifting in from the northwest. A surface trough sits
over the northern plains, with light winds across the CWA. Temperatures
are rising into the 70s and 80s.
Smoke will continue to drift into the region, and the HRRR shows
conditions worsening through Thursday, so have added mention in the
forecast. Other than that, tonight will be quiet, with lows around
60.
Mostly dry weather will continue Thursday, as the upper-level ridge
axis shifts over the northern plains. However, a few hi-res models
are showing some afternoon storms over the Black Hills, and some
evening storms moving into northeastern WY ahead of some weak upper-
level energy. Temperatures will warm into the 90s across much of the
area.
Upper flow will become more zonal Friday into the weekend. Periodic
shortwaves will bring a few chances for showers and thunderstorms,
but widespread precipitation is not expected. Highs will remain in
the 80s and 90s. Models are showing another ridge building over the
western states early next week, bringing the return of dry weather.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Thursday Evening)
Issued At 459 PM MDT Wed Aug 1 2018
VFR conditions expected through Thursday afternoon.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION...Pojorlie
AVIATION...7
Area Forecast Discussion
National Weather Service Las Vegas NV
157 PM PDT Wed Aug 1 2018
.SYNOPSIS...
Another day or two of isolated to scattered showers and
thunderstorms will be possible before rain chances begin to
diminish moving into late week and into the weekend. Temperatures
will drop a few degrees relative to the last several days with a
drier pattern expected moving into next week.
&&
.SHORT TERM...Tonight through Saturday night.
Beginning to see some convection occuring over the Sierra Nevada
Mountains this afternoon in addition to a few isolated cells
southwest of Rachel and near Mount Trumbull. HREF/HRRR solutions
diminish the activity over the Sierra Nevada by around 03-04Z but
hangs on to isolated activity in Mohave county a little longer.
PWAT values between 1.1 to 1.2 inches have been noted in RAP
mesoanalysis in this area with increasing DCAPE values as you
approach the Mohave/Clark County borders a bit farther west of
the current convection. This will likely be the area of highest
concern through the rest of the afternoon and evening due the
better potential for strong outflow winds and heavy downpours. All
activity subsides according to these hi-res solutions after 06Z,
thus have decreased PoPs substantially at that point.
An H5 shortwave from the Pacific Northwest will begin to push
this stubborn ridge eastward Thursday which will begin the
downtrend of precip chances moving into the weekend. During this
evolution Thursday and Thursday evening, mid level convergence and
modest upper level effects appear to phase, especially in the 12Z
GFS20 which could be the trigger for the last significant round of
precip Thursday afternoon and evening beginning first over the
Sierra Nevada and traversing the northern periphery of the CWA
including Esmeralda, Nye, and Lincoln Counties. As this feature
shifts eastward moving into Friday morning, drier air will
dominate the region and PoP chances dwindle moving into the
weekend.
&&
.LONG TERM...Sunday through Tuesday
A short period of H5 zonal flow will occur throughout the
southwest CONUS and a large, broad closed low approaches the
western seaboard by Sunday night. It does appear in the 12Z long
range models however that ridging will recover by mid-week and not
back down to this Pacific low. There is still some model
disagreement on the magnitude and orientation of the rebuilding
ridge axis, with the GFS much more amplified whereas the
Canadian/ECWMF are more broad. This may have some implications on
the possibility for moisture to return to the area and thus PoP
chances for the latter half of the week. At this time, opted for
the Canadian/ECWMF solutions which are the drier options.
Either way, the return of the ridge would likely kick high
temperatures up again a few degrees ending the slightly cooler
temperatures expected this weekend and early next week.
&&
.AVIATION...For McCarran...South winds, with gusts up to 20 knots,
will be likely this afternoon. The only complication to the wind
forecast will be outflow from thunderstorms that develop south and
west of the terminal. There is a slight chance of thunderstorms
developing in the valley this afternoon. Without influence from
convection, winds will remain south to southwesterly through the
evening and gusts will wane after sunset. A drying pattern will
limit thunderstorm activity Thursday and through at least Monday.
Gusty south winds are anticipated Thursday with speeds between 10-20
knots.
For the rest of southern Nevada, northwest Arizona and southeast
California...Scattered to isolated thunderstorms possible in the
Spring Mountains, Las Vegas valley, south Sierra, central Nevada,
and northwest Arizona this afternoon and evening. Erratic, sudden,
gusty outflows will be possible with thunderstorms. Best chances for
thunderstorm development will be in KBIH today.
Outside of thunderstorm influence, gusty south winds between 10-20
knots will be favored. Thursday, thunderstorms will be isolated to
central Nevada, northwest Arizona and the Sierra. Elsewhere, dry
conditions with gusty southerly winds, with speeds similar to
Wednesday, are expected.
$$
SHORT TERM...Boucher
AVIATION...Boothe
LONG TERM...Boucher
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