Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/22/18
Area Forecast Discussion
National Weather Service Albany NY
1140 PM EDT Tue Aug 21 2018
.SYNOPSIS...
A low pressure system moving into the eastern Great Lakes
Region and its warm front will bring showers and isolated
thunderstorms tonight. A cold front moves through Wednesday
morning into early afternoon with additional scattered showers
and thunderstorms, which should taper off by late afternoon as
it becomes breezy and less humid. High pressure builds in from
the west Wednesday night into Thursday with fair weather and
comfortable humidity levels heading into the weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 1140 pm EDT...The latest forecast this evening is in good
shape with just a few isolated showers as far north as the
Capital Region. The robust batch of showers and isolated
thunderstorms on the KENX and regional mosaic radar is over
eastern PA and NJ. This batch will move into the region between
06Z-09Z based on the latest 3-km HRRR and radar trends...and
move east of the forecast area between 11Z and 13Z.
Previous discussion...
After midnight, the bands of convection currently across PA are
expected to expand/track northeast. Chances for showers will
therefore increase for areas south and east of the Capital
Region at that time, and with some weak elevated instability, a
few rumbles of thunder will be possible. As PWAT`s increase to
near 2 inches, any deeper convective elements may contain
briefly heavy rain. Fortunately, it appears that forward
movement of convection should be quick enough to prevent more
significant hydrologic issues. Additional bands of
showers/embedded thunderstorms will also continue from Albany
and points N/W into the Mohawk Valley/Adirondacks and southern
VT/western MA.
It will be quite breezy tonight, as the core of a 40-50 KT low
level jet translates northeast through west/central NYS into the
St Lawrence Valley. Some wind gusts of 30-40 mph could occur
across portions of the southwest Adirondacks, and 25-35 mph
within the immediate Capital Region and other north/south
oriented valleys.
Lows mainly in the 60s, although some areas where wind persists
may only drop to around 70.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Wednesday, the system`s cold front should cross through the
region between roughly 12Z-16Z/Wed. It appears that the best
moisture and forcing may outrun the surface front, limiting the
potential for convection along the front. However, still can not
rule out some low topped convection, especially should any
breaks in the clouds occur before the front passes. Should this
occur, the combination of surface based CAPE of 400-800 J/kg
and deep layer shear of 25-35 KT could promote stronger
thunderstorms with gusty winds. This potential appears greatest
(although low overall) across southern VT, western MA and
perhaps northern Litchfield County, CT, with some possibility as
far N/W as the Taconics in NY. After the front passes, there
should be a significant decrease in showers with some sun
possibly breaking out, especially in valley areas. With the main
cold pool/upper trough aloft still approaching from the west,
additional isolated to scattered showers may develop, especially
across portions of the Adirondacks/Mohawk Valley. An isolated
thunderstorm could even occur, as sfc based instability
increases somewhat with the mid level cooling occurring. It will
be breezy in the afternoon, with temps mainly in the 60s for
higher elevations, and mid 70s/lower 80s in valley areas.
Wednesday Night-Friday, the aforementioned upper level trough
will move across the region late Wednesday night into Thursday.
Moisture will remain limited, although some lake moisture could
promote isolated showers across western areas Wednesday night.
Have indicated dry conditions for Thursday, but if the upper
level trough slows at all, isolated showers may develop with
diurnal heating. Dry conditions are expected for Thursday
night-Friday. It will be cool and much less humid through the
period, with daytime highs mainly in the 70s for valleys, and
60s across higher terrain, and overnight lows mainly in the 50s,
except for 40s across higher terrain, especially across the
southwest Adirondacks.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
At upper levels, a ridge will build into the southeastern CONUS
allowing for several disturbances to ride along the top of the ridge
and into the northeast. To start the period, an upper level
shortwave/low pressure system will skirt by to our north, with S-SW
flow resulting in warmer temperatures and gradually increasing
humidity levels. Saturday looks to be the nicer of the two days for
the weekend, as some unsettled weather may arrive on Sunday. The
ridge aloft is expected to flatten out by Sunday, as additional
short wave energy moves in from the Great Lakes. Still, it is
unclear how much instability/forcing will be present, so will only
mention slight to low chance pops with the better chances west of
the Hudson Valley.
Additional short wave energy may move through on Monday as well as
the upper level ridge strengthens across the Tennessee Valley. This
set up would result in more unsettled weather early next week with
multiple chances for showers and thunderstorms and continued above
normal temperatures. In fact, we may even see temperatures take a
late-season run at the 90 degree mark Monday and Tuesday, especially
for the mid-Hudson Valley region.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
An unseasonably strong low pressure system tracking into western
Quebec will usher in increased moisture and rain showers
overnight. Ceilings are expected to fall to MVFR in the vicinity
of 05Z with showers increasing at this point and resulting in
MVFR visibility at times. Cigs/vsby could fall to IFR at times
especially from 07-13Z in heavier downpours. An isolated
thunderstorm cannot be ruled out in this time frame, although
potential is too low to include in the TAFs at this time.
Deeper moisture will be exiting after 12-13Z along with
coverage of rain showers. Expect a gradual improvement to VFR
conditions by the late morning/early afternoon. A few isolated
showers could linger at times into the afternoon.
Winds tonight will be from the southeast at around 10 kt,
gusting to around 20 kt at times at KALB. Winds at 2kft will be
in the 30-40 kt range, so will have to watch for surface winds
calming out overnight, which would result in LLWS conditions.
Have included LLWS at KGFL where the winds above the ground
should be strongest. Winds will shift to southwesterly mid-
morning and westerly by the afternoon. There could be some gusts
of 20-25kt during the afternoon hours, especially at KALB/KPSF.
Outlook...
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Low Operational Impact. Slight Chance of SHRA...TSRA.
&&
.FIRE WEATHER...
A low pressure system moving into the eastern Great Lakes
Region and its warm front will bring showers and isolated
thunderstorms tonight. A cold front moves through Wednesday
morning into early afternoon with additional scattered showers
and thunderstorms, which should taper off by late afternoon as
it becomes breezy and less humid. High pressure builds in from
the west Wednesday night into Thursday with fair weather and
comfortable humidity levels heading into the weekend.
The RH values will recover to around 100 percent tonight. The
min RH values will be 50 to 75 percent Wednesday afternoon.
It will remain breezy overnight with south to southwest winds
of 10 to 20 mph, with some gusts of 25 to 35 mph possible,
especially across the southwest Adirondacks and within the
Capital Region of NY. Winds will shift to the west to northwest
at 10 to 20 mph by Wednesday afternoon with gusts in the 25 to
35 mph range.
A widespread wetting rain is likely tonight through Wednesday
morning.
&&
.HYDROLOGY...
Showers will increase tonight into early Wednesday ahead of a
strong low pressure system and its warm and cold fronts, with
isolated to scattered thunderstorms possible Wednesday morning
into the early afternoon. Total QPF ranges from a few tenths of
an inch to an inch from the system, with greatest amounts
expected across portions of the southwest Adirondacks and
western Mohawk Valley region.
Some minor within-bank river rises are possible, but no
widespread problems are currently anticipated. Locally heavy
downpours could also lead to ponding of water in poor
drainage/urban areas.
Dry weather returns Wednesday night into the Saturday, as river
flows recede again.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...KL/Wasula
NEAR TERM...KL/Thompson/Wasula
SHORT TERM...KL/Wasula
LONG TERM...JVM
AVIATION...Thompson
FIRE WEATHER...KL/Wasula
HYDROLOGY...KL/Wasula
Area Forecast Discussion
National Weather Service State College PA
1100 PM EDT Tue Aug 21 2018
.SYNOPSIS...
A cold front will move east of central Pennsylvania by
Wednesday morning. This will bring an end to the wet conditions
that we have seen in recent weeks. Cooler and less humid air
will move into the area on Wednesday, as high pressure moves
eastward and and prevails for the rest of the work week. While
temperatures will warm to above normal levels by early next
week, showers and storms will be more scattered in nature than
what we have seen in recent weeks.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Severe threat has faded while minor flooding has become the
primary focus over the Lower Susq where warm front conts to lift
northeastward and earlier storms have become disorganized and
continue to rain out.
Farther west and north, two broken lines of showers and storms
are along and ahead of the approaching cold front, which will
keep chc shra/tsra going for much of the overnight. Here too
the severe threat has diminished, but with well mixed warm
sector and favorable EHI values, will remain vigilant as the
front crosses through the late evening hours.
Locally heavy rain threat appears to wind down around midnight
over the southeast. Then the first front of drier air pushes
through. Drier air won`t arrive over the southeast until around
sunrise Wed.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
Wed looks unstable as colder air aloft moves in and we get some
mixing. Likely pops over the NW half, with 30-40s over the rest
of the area. Should be a post-frontal day with the sky almost
filled over most of the area. Showers will be brief as they will
be cellular and moving along quickly.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
It dries out Wed PM as high pressure will float in for a few
days. Lower humidity will allow for comfortable and pleasant
days with plenty of sunshine followed by mainly clear and
relatively cool nights with valley fog. The next front, which
could bring scattered showers and thunderstorms back into the
area, approaches on Saturday.
Regardless of the outcome, the weekend does not look like a
wash out and will probably be mainly dry in most areas.
Temperatures and humidity levels will start to creep upward with
highs climbing back above average by Sunday.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A cold front entering northwest Pa at 03Z will push southeast
across the region overnight, accompanied by scattered showers a
few thunderstorms. HRRR and radar trends indicate tempo IFR
vis/cigs are possible from heavy showers/storms in the vicinity
of KMDT/KLNS between 03Z-05Z. Low level moisture over the
eastern half of the state may be scoured out ahead of the
approaching cold front, leading to improving cigs across the
eastern airfields from KIPT south through KLNS after midnight.
The cold front will push southeast across the region late
tonight, ending the threat of showers and thunderstorms.
However, post-frontal low level moisture ascending the
Appalachians is likely to result in IFR/LIFR cigs from KBFD
south through KJST, while downsloping westerly flow results in
VFR conditions late tonight across the lower elevation airfields
across southeast Pa.
Model soundings and SREF/HREF probability charts indicate IFR
cigs are likely to linger through late morning over the high
terrain of the Appalachians, while downsloping flow yields more
favorable conditions further southeast. By afternoon there is a
high confidence of predominately VFR conditions across most of
central Pa, with high MVFR/low VFR cigs likely from KBFD to
KJST. However, scattered showers associated with the passage of
a secondary cold front could produce brief vis reductions
during the afternoon.
.Outlook...
Thu...No sig wx expected.
Fri...Patchy AM fog possible.
Sat...No sig wx expected.
Sun...Isold PM tsra impacts possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Dangelo/Martin
NEAR TERM...Dangelo/DeVoir
SHORT TERM...Dangelo/Martin
LONG TERM...Lambert/Martin/Tyburski
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Cheyenne WY
655 PM MDT Tue Aug 21 2018
.UPDATE...
Issued at 639 PM MDT Tue Aug 21 2018
Rain showers continue to develop and spread east into the plains
this evening, but mainly across Colorado with only isolated
activity across southeast Wyoming. Models have shifted a bit
southward with the precip shield. Will keep an eye on this trend,
as there is still a large area of moderate rainfall lifting
northeast across western Colorado. May need to cancel the Flood
watch for the Snowy Range a few hours early if current trends
persist.
&&
.SHORT TERM...(Tonight - Wednesday Night)
Issued at 149 PM MDT Tue Aug 21 2018
The main forecast concern/highlight over the next 12-24 hours will
continue to be the potential for flash flooding, mainly during the
evening/overnight hours tonight. Shower & thunderstorm activity is
already starting to increase in coverage & intensity along the I80
corridor in southeast Wyoming, and this trend is likely to persist
through the evening w/ numerous mid-level disturbances embedded w/
in the flow. High-resolution guidance, including the HRRR has been
rather consistent showing multiple waves of moderate to heavy rain
over the next few hours, w/ the most steady rain occurring between
00z-06z as divergence aloft becomes maximized in the vicinity of a
stalled mid-level boundary. Models have trended further south with
this precipitation shield, so there is a bit of uncertainty w/ the
northern extent of where this will set up. Even so, PWAT values of
0.75-1.0 inches are well above climatological normals and forecast
sounding data suggests a favorable environment for efficient rain-
fall production. Flash flooding is a realistic threat should heavy
rain producing storms train over the same area, especially for the
Badger Creek Burn Scar which already picked up around 0.25 to 0.50
inch of rain earlier this afternoon. We will continue with a Flash
Flood Watch for the Snowy Range until midnight. Extensions did not
appear warranted w/recent model trends, but the evening shift will
need to monitor closely.
An unsettled pattern will likely continue through Wednesday, given
moist southwest flow in advance of yet another mid-lvl disturbance
and associated cold front tracking across the Intermountain West &
into western Wyoming by mid-day. The best chance for convection in
the afternoon will be along/west of the Laramie Range. Coverage is
not expected to be quite as widespread as today/tonight, but could
still become quite numerous w/increasingly difluent flow aloft and
some weak jet energy moving overhead. A few showers and storms may
linger into early Thursday morning as well.
.LONG TERM...(Thursday - Tuesday)
Issued at 402 AM MDT Tue Aug 21 2018
A larger pattern change will come Thursday afternoon with the
passage of the shortwave trough over and then east of the region.
An H5-H7 drier airmass will shift over the region and shunt the
deeper moisture east prior to the strong height falls, generally
leading to a dry frontal passage. Limited to no cold air advection
is being advertised per the models so temperatures should not
drop off behind the boundary into the weekend. A large scale H5
ridge looks to form over the Mississippi River valley over the
weekend and into early next week placing the region under SW flow
and the return of some embedded shortwave troughs could enhance
shower activity by Saturday afternoon with a possibly calmer
Sunday as we could be between waves. Will need to watch early next
week for a possible stronger trough developing across the
northern Rockies and a side-swipe of a colder airmass.
&&
.AVIATION...(For the 00Z TAFS through Wednesday afternoon)
Light rain and some thunder is moving west to east across southeast
Wyoming and the southern Nebraska panhandle. Brief MVFR to near IFR
VIS possible in the heaviest showers. After the shower activity
dissipates or moves southeast of the area, IFR conditions and fog
are possible, mainly from KCYS to KSNY later tonight into Wednesday
morning.
&&
.FIRE WEATHER...
Issued at 402 AM MDT Tue Aug 21 2018
Widespread wetting rain is expected across the southern half of
the forecast area from Seminoe Dam towards Kimball, Nebraska
through the day and especially this afternoon and evening. Some of
the higher terrain of the Snowys and southern Laramie Range could
see upwards of 1 to 1.5 inches through the next 24 hours in
isolated locations. The Badger Creek burn scar is included in this
higher precipitation potential zone and a flash flood watch as
been issued for the burn scar area as rapid flash flooding and
debris flows could occur between noon to late this evening.
Caution is urged in this area.
Isolated to scattered showers are expected again tomorrow and
Thursday but overall coverage will be less then today and this
evening. fire weather concerns will be minimal with high relative
humidity values.
Fire weather concerns return Friday with a drier airmass moving
into place but recent rainfall could mitigate overall fire weather
danger. None-the-less, elevated to near-critical parameters could
be in place with lower humidity and higher wind speeds.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Flash Flood Watch until midnight MDT tonight for WYZ114.
NE...None.
&&
$$
UPDATE...TJT
SHORT TERM...CLH
LONG TERM...JSA
AVIATION...TJT
FIRE WEATHER...JSA
Area Forecast Discussion
National Weather Service Dodge City KS
1100 PM CDT Tue Aug 21 2018
...Updated Aviation...
.SHORT TERM...(This evening through Wednesday)
Issued at 347 PM CDT Tue Aug 21 2018
The mid afternoon surface analysis showed increasing upslope flow
component across southeastern and east-central CO with mid 50s to
lower 60s dewpoints across this region. Thunderstorms were already
developing as of 20z over the Sangre de Cristo mountains, and it is
this terrain-induced convection which will continue to grow upscale
through the early evening as they move across far southeast
Colorado. The latest HRRR suggests that initial MCS activity will
reach southern CO-KS border by 02-03z this evening. This MCS should
maintain integrity through 06z as it marches across southwest
Kansas, and this should be the main event for most locations. The
MCS should eventually weaken in the 06-10z, but other lighter to
moderate showers and thunderstorms will continue to march east
through the early morning hours as they head deeper into southwest
and eventually central and south central KS. The best severe weather
risk will be closer to the CO border, but even that should be just a
wind risk of 50-60 mph gusts. There should be enough forward
propagation of the MCS to limit flash flood risk, but it will
definitely need to be watched.
Scattered convection will continue all along the 850-700mb
frontogenetic zone through late morning Wednesday with the majority
of the precipitation moving deeper into central Kansas after 18z
Wednesday. The surface front itself will remain nearly stationary
along the OK-KS border Wednesday afternoon, so a redevelopment of
surface-based convection is expected somewhere across far southwest
KS into the OK Panhandle. Post-frontal upslope winds will again
favor southeastern Colorado storms, which would then push east into
far western Kansas Wednesday evening. The atmosphere will likely be
quite worked over with the 850-700mb frontogenesis weakening some as
the thermal gradient in this layer loosens. While there will be
scattered showers and storms late Wednesday Night into early
Thursday morning, the organization of the activity should be less
than tonight`s event. Nevertheless, the combined events in total
should yield widespread three-quarters of an inch to one inch of
precipitation with pockets of higher amounts, as is always the case
with convection.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 347 PM CDT Tue Aug 21 2018
A drying out period is expected for the Long Term beginning late
Thursday as the polar baroclinic zone shifts back north with the
passage of the next storm system well to our north. That said, there
will still be one last opportunity for some thunderstorm activity
across mainly south central Kansas late Thursday afternoon/evening
along the weak cold front tied to mentioned Northern Plains storm
system. The weekend into early next week forecast certainly looks
warmer with highs in the lower 90s most locations on deep southwest
momentum, allowing 850mb temperatures to warm back up into the upper
20s degC. A broad positively-tilted trough will enter the Rockies
early to mid next week with a jet core across the Central Rockies
extending from southwest to northeast. This does not bode well for
precipitation across southwest Kansas with continued dry downslope
warming across a deep layer of the troposphere extending into
western Kansas. Eventually, another polar front will reach southwest
Kansas, but probably not until at least 30 August or so, just beyond
this Long Term period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1100 PM CDT Tue Aug 21 2018
Widespread rain and embedded thunder, along and west of a GCK-
LBL line as of 04z, will continue to move east through 09z. Models
show the MCS weakening with time, as such rain and thunderstorm
coverage will wane through the night. Consensus of short term
models build stratus into all of the airports during the 12-15z
Wed time range, and keep it locked in at DDC/GCK/HYS for the
balance of the remainder of the TAF period. Stratus cigs will
average MVFR, but may drop to high end IFR at times. The exception
to this will be LBL, where cigs are expected to improve to BKN070
after 18z Wed. Scattered showers will remain possible throughout
the TAF period, with occasional reductions in vis due to -RA/BR.
Winds will remain E/SE through this TAF cycle, with the strongest
SE winds at LBL toward 00z Thu, gusting near 25 kts.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 77 66 92 / 70 50 50 10
GCK 59 77 64 91 / 90 50 50 10
EHA 61 84 66 92 / 90 40 40 20
LBL 63 84 67 94 / 80 40 40 20
HYS 59 68 64 87 / 60 70 50 10
P28 65 78 67 94 / 60 60 40 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Turner
Area Forecast Discussion
National Weather Service Quad Cities IA IL
616 PM CDT Tue Aug 21 2018
...00z AVIATION UPDATE...
.SYNOPSIS...
Issued at 246 PM CDT Tue Aug 21 2018
The synoptic low which brought heavy rain and widespread cloud over
to the Midwest yesterday, is slowly weakening and move well to the
east. Mid level dry air has limited shower development in our area
today, though dewpoints in the lower to mid 60s have still allowed
for plenty of stratocumulus on the back side of the low. For our
northwest, this has been a cool day in the 60s, though a high in the
lower to mid 70s is still attainable if breaks in the clouds
develop. Farther southeast, a northwest breeze at 10 to 20 mph has
been blowing, with temperatures in the mid 70s to lower 80s.
&&
.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 246 PM CDT Tue Aug 21 2018
Tonight should be a dry night, if you believe all models except the
HRRR. The HRRR brings a few cells through the heart of the area
around 7 PM, and that seems overdone, but enough to have us in the
10% range on POPs early this evening. Otherwise, expect skies to
slowly thin to clear this evening, with shallow moisture depositing
out as dew overnight. That will allow the dewpoints to fall to the
50s, closely followed by the temperature. Lows in the lower 50s
north to upper 50s far south will be forecast for lows. I do not
think fog will be widespread, as we keep a northwest wind around 5
to 8 mph tonight.
Wednesday appears quiet, and very pleasant, with low dewpoints and
highs back in the upper 70s to lower 80s. This is forecast by all
guidance as the high pressure moves over the region.
ERVIN
.LONG TERM...(Wednesday Night through Tuesday)
ISSUED AT 246 PM CDT Tue Aug 21 2018
Three main features in the long term period to discuss. First, the
beginning of week into Friday will feature temperatures and
dewpoints much more like September than August. The next, a rather
potent upper level trough is forecast to move through the flow
across the area. It has been a while since decent vorticity
advection was forecast for the area. After this system moves
through the area, we will return to hot and humid conditions for the
weekend into next week. We are definitely not done with summer.
Overall quiet weather is expected as northwest flow remains across
the area through the end of the week. Friday, largescale flow turns
southwest and induces moisture return ahead of an H5 wave. This
will occur at the heat of peak heating across central Iowa. Model
guidance suggests convection will fire across this area and move to
the east into our area. Deep layer shear will be sufficient for
organized convection and likely strong and even severe weather if
storms develop. Along with this threat, decent rain across the CWA
looks likely as well. This system will be likely the main forecast
concern through the period.
This weekend a return to hot and humid temps is expected.
Conditions may warrant heat advisories.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
ISSUED AT 609 PM CDT Tue Aug 21 2018
Leftover MVFR cigs from a departing storm system will diminish
this evening, allowing VFR conditions to prevail for the remainder
of the TAF period as high pressure builds across the Midwest.
Gusty northwest winds around 10-15 kts will decrease to 5-10 kts
as the evening progresses.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Ervin
SHORT TERM...Ervin
LONG TERM...Gibbs
AVIATION...Speck
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
658 PM CDT Tue Aug 21 2018
.AVIATION...
/00Z TAFs/
Challenges: Nothing major, just minor wind shifts less than 10
knots. VFR throughout the forecast for all airports.
NE winds around 10 knots this evening will become light E-ESE
Wednesday 4-6 knots. Any haze being drawn down across parts of
the area from wildfires across the PAC NW and Rockies is becoming
more elevated and do not expect any VSBY restrictions the next 24
to 30 hours.
Isolated TS/-SHRA will remain south of Waco and in the vicinity of
a weak surface front over Central TX that is expected to wash out
the next 24 hours. A broad surface ridge of high pressure will
remain anchored across E TX and through the Lower MS Valley
tonight and Wednesday...resulting in wind speeds less than 10
knots.
05/
&&
.SHORT TERM... /Issued 326 PM CDT Tue Aug 21 2018/
/Tonight/
Thunderstorms will remain possible this evening across the
Central Texas counties due to the presence of a weak front.
Activity has already developed along a line from Goldthwaite to
Hearne, and may increase in coverage over the next couple of
hours. Outflow mergers should once again allow isolated storms to
persist an hour or so after sunset. Good instability is present
along the front, so a few storms will be capable of producing
gusty winds and frequent lightning. The lack of shear and overall
weak flow at all levels will keep the severe threat fairly low.
Storms will dissipate late this evening giving way to a mostly
clear and dry overnight period. Smoke carried into the region from
wildfires in the Northwest States will keep the hazy conditions
going through the night, following what may be another
picturesque sunset. Pleasant conditions can be expected north of
the front with lows falling into the upper 60s from I-30 to the
Red River. Lower and middle 70s can be expected elsewhere.
30
&&
.LONG TERM... /Issued 326 PM CDT Tue Aug 21 2018/
/Wednesday and beyond/
Quiet, rain-free, and hot weather is expected through next week
as an upper level high parks itself over Texas and the Southern
Plains. Hazy conditions will continue on Wednesday as smoke from
ongoing wildfires by the Canadian Rockies lingers across North
and Central Texas. Conditions should be similar to today as the
vertically integrated smoke amounts from the experimental HRRR
remain nearly the same. Visibility will still remain above 5
miles, but the combination of the smoke from wildfires and high
amounts of ozone will be unhealthy for sensitive groups.
Temperatures will be near normal across North Texas and slightly
above normal across Central Texas.
As the upper level high builds over North and Central Texas and
subsidence increases, the return of triple digit heat is expected
on Thursday in Central Texas and Friday across the region.
Southerly low-level winds are expected to organize into this
weekend and will allow for temperatures to "cool" slightly. Highs
will be in the mid to upper 90s through next Wednesday. Heat
index values will top out between 99 to 103 degrees as dewpoints
mix out each afternoon. There are some areas east of I-35 that may
reach heat advisory criteria early next week and we`ll continue
to monitor this potential.
Villanueva
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 73 96 75 97 78 / 0 0 0 0 0
Waco 73 100 74 101 77 / 10 0 0 0 0
Paris 67 91 70 94 72 / 0 5 0 5 0
Denton 68 95 72 98 76 / 0 0 0 0 0
McKinney 68 94 72 96 75 / 0 0 0 0 0
Dallas 74 97 76 99 79 / 0 0 0 0 0
Terrell 69 96 73 97 76 / 0 0 0 0 0
Corsicana 71 97 73 98 76 / 5 0 0 0 0
Temple 73 100 72 100 75 / 20 5 0 0 0
Mineral Wells 70 96 71 99 74 / 5 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
05/91
Area Forecast Discussion
National Weather Service Wilmington NC
816 PM EDT Tue Aug 21 2018
.SYNOPSIS...
Showers and thunderstorms will be possible through early
Wednesday ahead of an approaching cold front. The strong August
front will clear the coast before daybreak Thursday, bringing a
drying and cooling trend to the region Thursday and Friday.
Canadian high pressure extending along the interior of the
Carolinas, may help bring in Atlantic moisture and light rain
showers to the coast next weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 815 PM Tuesday...The forecast area was largely void of
precip until late afternoon, when a few showers and
thunderstormsmanaged to fire up in the vicinity of the sea
breeze boundary. This activity has diminished with the loss of
daytime heating, however there will be potential for additional
convection this evening and overnight, which will be associated
with a mid- level shortwave currently moving across the western
Carolinas. Despite loss of heating, the airmass will remain
unstable overnight, and current radar trends bring ongoing
storms into western Darlington and Marlboro counties by 02Z.
Will maintain low chance PoPs in the forecast overnight as the
shortwave traverses CWA, with favored areas being north of a
Florence to Whiteville line. The HRRR has also maintained some
consistency with some additional flare up possible after 09Z in
the vicinity of Cape Fear.
Shortwave pushes off the coast Wed morning with post wave
subsidence and mid-level drying likely bringing an end to any
overnight convection. Cold front will approach from the
northwest as 5H trough moves into the area. West to northwest
flow aloft will limit moisture return ahead of the front which
will have a negative impact on diurnal convection. Best chances
will again be along the sea breeze, especially at the Brunswick
inflection point, during the afternoon hours. Highs Wed will be
near to slightly above climo with most areas in the upper 80s to
lower 90s.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 3 PM Tuesday...Surface low pressure moving through the
Canadian maritime provinces and high pressure advancing eastward
through the Ohio Valley will together push a cold front through
the eastern Carolinas Wednesday night. This is our first cold
front of the approaching Fall season and promises to bring at
least 36 hours of drier, Canadian air southward into the
Carolinas.
Before the front gets here Wednesday evening, an unstable airmass
could still produce scattered showers and thunderstorms, especially
near the coast. Convective activity should end as the front arrives
during the late evening hours. An approaching upper disturbance and
right-entrance region of a 250 mb jet will probably arrive too late
to do more than produce some post-frontal mid-level clouds
around 7000 feet up, visible on GFS/NAM forecast soundings.
850 mb temps have been averaging +18C for the past couple of weeks,
but should cool to around +15C behind the front Thursday. Even with
plenty of sunshine highs should only reach the mid 80s, 3-5 degrees
below normal. Dewpoints in the 60s (or even upper 50s west of I-95)
should yield apparent temperatures not significantly different than
the actual air temperatures! Mainly clear skies Thursday night and
good radiational cooling conditions are expected as the surface high
moves across the Mid-Atlantic states. Inland temperatures should
fall into the 60-65 degree range, however northeasterly winds near
the coast will keep air temps warmer since water temps are still in
the 80s.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 3 PM Monday...A rather flat pattern aloft will be in place at
the onset of the long term period as H5 subtropical high continues
across TX and ridges eastward across the Deep South. During this
time the main shortwave energy will remain north of the area as it
transits the Great Lakes Region Friday into Saturday, then New
England during Sunday. Meanwhile at the surface Friday the forecast
area will be in the post-frontal regime with high pressure ridging
across the Carolinas from the Mid-Atlantic states. A trough (the old
front) will drift back toward the coast this weekend but is progged
to become absorbed in the larger scale flow from high pressure
farther offshore. The chance of showers/tstms will be very low
Friday/Saturday in the stable/drier conditions behind the old front.
Some instability is shown to return to the area during Sunday with
only low POPs needed at this time. The sea breeze is expected to
become more active Mon-Tue time frame as precipitable water could
approach 2 inches again. MEX high/low temperatures appear
reasonable, thus did not stray too far from them.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 00Z...Convection near the coast will keep VCSH through 03Z.
Convection in western South Carolina will push into our western
counties by 02Z, weakening as it does so. Little to no fog is
expected overnight. There will be enough instability and lift to
kick off some weak convection at the coastal terminals toward
morning. Wednesday, showers push off the coast and take a lot of the
deep moisture with them. The atmosphere may have time to reload in
the afternoon, but expect only isolated convection due to lack of
mid and upper level moisture. Southwest flow through the period.
Extended Outlook...A frontal passage is expected early Thursday with
a drying trend, and VFR conditions Thursday and Friday, with NE
surface winds. MVFR ceilings possible Saturday at coastal terminals
as Atlantic moisture and -RA moves ashore.
&&
.MARINE...
NEAR TERM /THROUGH WEDNESDAY/...
As of 815 PM Tuesday...A few showers and isolated thunderstorms
have quickly dissipated as they moved off the coast late this
afternoon. Not expecting any additional convection over the
waters until perhaps 3-6 AM, when a shortwave will move off the
coast. Otherwise, the period will be dominated by southwest
flow with combination of nocturnal jet and tightening gradient
maintaining winds in a 15 to 20 kt range overnight, with a few
gusts to 25 kt. Speeds will remain 15 to 20 kt on Wed as a cold
front slowly approaches from the northwest. Seas of 2 to 4 ft
tonight will build to 3 to 4 ft on Wed and may reach 5 ft at
times in the vicinity of Frying Pan Shoals.
SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 3 PM Tuesday...The first Canadian cold front of the
approaching Fall season will move through the coastal waters and
offshore Wednesday night. Average model timing of the frontal
passage has sped up a few hours from yesterday`s model runs, and
it now appears the front should push offshore between 2-4 AM
Thursday morning. Behind this front, high pressure over the Ohio
Valley will build eastward, pushing a drier Canadian airmass
into the area on breezy north and northeast winds.
Prefrontal SW winds around 15 kt should shift to the north late
Wednesday night. Winds will diminish Thursday afternoon due mainly
to diurnal effects weakening the pressure gradient along the coast,
but rising pressures inland Thursday night due to boundary layer
cooling and the approach of the synoptic high should increase NE
winds to 15-20 kt. Duration of winds will hopefully keep seas below
6 feet, although wave conditions should become quite choppy away
from shore as the fetch will be become long in a NE wind.
LONG TERM /FRIDAY THROUGH SUNDAY/...
As of 3 PM Monday...High pressure will ridge across the Carolinas
from the Mid-Atlantic region in the post-frontal regime. The flow
will be from the northeast through Friday night. A trough east of
the waters Saturday will weaken as it moves toward the coast.
Thus after a period of northeast winds the flow will veer to an
east-southeast direction, especially once the trough dissipates.
Speeds will be highest during Friday in the northeast fetch, but
conditions while not optimal, should remain below Small Craft
thresholds. Otherwise, choppy seas in the northeast fetch Friday
will gradually subside through Saturday, but more-so during
Sunday.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
NEAR TERM...CRM/III
SHORT TERM...TRA
LONG TERM...SRP
AVIATION...DL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
944 PM EDT Tue Aug 21 2018
.UPDATE...
Issued at 944 PM EDT TUE AUG 21 2018
Updated the forecast and hazardous weather outlook to remove
mention of thunder for the rest of tonight. Also decreased
precipitation chances across the board per the latest trends in
radar and the HRRR model. Lastly, ingested the latest obs into
the hourly forecast grids to establish new trends there.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 357 PM EDT TUE AUG 21 2018
Aloft, mid latitude trough will pass through the eastern CONUS
through the short term period. There are several distinct
shortwaves rounding the based of the trough as it pushes east. At
the surface, a cold front is currently moving across the
Commonwealth. This feature will pass to the east of our area later
this evening, or tonight. Numerous showers have developed ahead
of the surface front, aligned in bands that gradually shift to the
east with time. Precip rates have not been impressive with this
activity and models all agree that PWATs should begin decreasing
across the region over the next several hours. However, a few
cells could still produce some brief heavy rainfall and some gusty
winds, despite a definite drop in MLCAPES through the remainder
of the afternoon.
Sensible weather features a brief change in our weather, or more
specifically a short break from the humid and warm conditions of
late. A cold front that will pass through our area tonight. As a
result showers will gradually diminish through the evening, and
then possibly increase for a short period of time early Wednesday
morning as a post frontal trough brings in the true shot of drier
and cooler air. Afternoon highs will climb into the mid and upper
70s by midweek. Overnight lows will feel quite chilly as well
dropping into the mid 50s Wednesday night into Thursday morning.
Could it be we will be able to detect a hint of fall in the air?
.LONG TERM...(Thursday through Tuesday)
Issued at 357 PM EDT TUE AUG 21 2018
The extended period will start off with unseasonably cool
temperatures. In fact, highs on Thursday should only make it into
the upper 70s across the area. By Friday morning, we can expect low
in the mid to upper 50s across eastern Kentucky. The cooler readings
should continue on Friday and Saturday, with highs each of those
days in the low to mid 80s. From Sunday onward, we should see normal
readings in the mid to upper 80s each day and in the mid to upper
60s each night. Rain chances should be few and far between in the
extended. Thursday and Friday should be dry with partly cloudy to
mostly sunny skies. A few showers and storms will be possible at
times from Saturday through Tuesday. Any thunderstorms will likely
occur during the afternoon and evening hours each day. A trough of
low pressure will be the trigger for showers and storms, as it moves
slowly across the northern CONUS.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 744 PM EDT TUE AUG 21 2018
Scattered rain showers will be moving across eastern Kentucky
tonight and through early Wednesday afternoon, before finally
exiting the area. The showers have been moving close enough to the
TAF sites this evening to warrant including VCSH in all five TAFs
for now. May amend this out later tonight as the activity becomes
even more scattered out. Winds should be generally out of the
west to northwest at 5 to 10 mph through out the period. SCT to
BKN low and middle level clouds will persist during the period as
well, with the more widespread clouds moving across the area
tonight into early tomorrow morning. A few of the TAF site may
experience MVFR fog tonight into early tomorrow morning.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...RAY
LONG TERM...AR
AVIATION...AR
Area Forecast Discussion
National Weather Service North Platte NE
651 PM CDT Tue Aug 21 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 324 PM CDT Tue Aug 21 2018
A couple of strong disturbances are moving through the central and
southern Rockies. The ongoing disturbance over nrn Colo is progged
to move south of Nebraska. A second disturbance across Utah is
expected to brush swrn Nebraska late tonight and Wednesday.
Showers and isolated thunderstorms are in the forecast using a blend
of model consensus data, the HRRR model and the RAP model. This
forecast tracks the rain mostly through swrn Nebraska (south of I-
80) as suggested by the SREF model. The HREF model suggested rain
chances well north of Interstate 80 and is the HREF was not used for
the forecast.
Blended guidance plus bias correction was the basis for the low
temperatures tonight and highs Wednesday. This produced lows mostly
in the 50s tonight and highs in the 60s and 70s Wednesday.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 324 PM CDT Tue Aug 21 2018
Thursday will warm ahead of stronger system dropping into the
Pacific northwest and will be heading toward the northern plains. A
surface trough will extend roughly along highway 83 from Valentine
to North Platte Thursday afternoon. A decent amount of shear and
instability will be present near the trough, and feel at least
isolated thunderstorms are possible late in the afternoon along the
boundary. A supercell or two could evolve and contain large hail and
damaging winds.
After Thursday that will be pretty much in for rainfall as upper
level ridging nudges northward into the area for the weekend. It
will turn much warmer as well, with highs back into the 90s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 649 PM CDT Tue Aug 21 2018
VFR is expected for much of tonight, however, an upper level
disturbance will move across southwestern Nebraska late tonight.
This will bring scattered showers and isolated thunderstorms to
southwestern Nebraska early Wednesday morning.
MVFR with some IFR cigs and vsby will develop for southwestern
Nebraska generally along and south of I-80 between 12z-00z
Wednesday. Across our northern terminals VFR conditions will exist
throughout the period.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...Taylor
AVIATION...Jacobs/Thorne
Area Forecast Discussion
National Weather Service Lake Charles LA
1025 PM CDT Tue Aug 21 2018
.DISCUSSION...
Sfc analyses show the cool front gradually oozing swd across the
forecast area this evening. Convection which initiated earlier,
and expanded in coverage as the front collided with the afternoon
sea breeze, has been steadily diminishing in intensity/coverage
over the last hour. Having said that, no reason why we won`t see
a few rogue showers/storms through the night, especially once the
front hits the coastal waters later tonight. POPs/wx grids have
been adjusted per 88D and high res guidance trends through the
evening with one last update through the 12z time frame just sent
out. Elsewhere, inherited grids/zones looked in good shape.
25
&&
.PREV DISCUSSION... /issued 641 PM CDT Tue Aug 21 2018/
AVIATION...
A leading edge of a surface front continues to progress southward
this evening while the Gulf breeze advances inland. Showers and
thunderstorms are developing as these boundaries collide and will
result in the potential for VCSH/VCTS at KBPT and KLCH through
03Z. Coverage of convection is expected to be more isolated
further to the east and VCTS was only included at KLFT where it is
currently ongoing. South to southwest winds at KARA/KBPT/KLCH/KLFT
will shift to westerly after 03Z and become variable during the
overnight hours as the front pushes southward. With the passage of
the front, winds will become northerly at around 5 knots and
persist through the day tomorrow.
PREV DISCUSSION... /issued 255 PM CDT Tue Aug 21 2018/
DISCUSSION...
Wx map shows cool front over inland SE TX/C LA this afternoon,
with dewpoints in the mid to upper 60s behind the front. Ahead of
the front, dewpoints in the lower to mid 70s, along with
temperatures in the mid 90s, yielding heat index values ranging
from near 100 to as high as 106, with the upper end across the
I-10 corridor south of the front. Radar showing much less activity
than earlier anticipated, with only a few showers across
Atchafalaya bay.
For this evening, the cool front will gradually move through SE
TX/S LA. Not a lot of support for shower and thunderstorm
development with the latest HRRR guidance showing isolated
coverage at best along the I-10 corridor into the coastal waters
this evening. Thus, lowered the chances of precipitation to 20%
late this afternoon into the early evening hours.
Behind the front, slightly lower dewpoints in the mid to upper 60s
should keep morning lows in the upper 60s to lower 70s Wednesday
through Friday. Afternoon highs will still be in the lower to mid
90 during this period, but the lower dewpoints will keep the heat
index lower for these days.
By Friday afternoon into early next week, the mid to upper level
high expected to build over the southern U.S. with the typical
late summer surface high off the east coast. While the upper high
over the region usually spells oppressive heat, we should see
enough of a southeast flow off the Gulf to bring moisture off the
Gulf and the return of scattered afternoon showers and thunderstorms
during this period.
MARINE...
Light southwesterly winds will become more westerly as a frontal
boundary slowly moves south over the area this evening and
overnight. The front will gradually drift southward over the
coastal waters through Wednesday, before becoming stalled.
Isolated showers and a few thunderstorms will be possible along
the front, with rain chances diminishing by Thursday as drier air
filters into the area. A brief period of offshore flow is expected
to develop by mid-week, with onshore flow resuming by Friday as
the front gradually dissipates.
DML
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 68 94 67 95 / 10 10 10 10
LCH 75 95 73 94 / 40 10 10 10
LFT 74 94 73 94 / 10 10 10 10
BPT 77 95 76 94 / 40 10 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Midland/Odessa TX
603 PM CDT Tue Aug 21 2018
.DISCUSSION...
See 00Z aviation discussion below.
&&
.AVIATION...
Isolated TS current seen across the area should not affect any of
the TAF sites before dissipating after sunset. VFR conditions and
generally light southeast winds will continue.
Hennig
&&
.PREV DISCUSSION... /issued 310 PM CDT Tue Aug 21 2018/
DISCUSSION...
WV imagery shows a broad upper ridge covering the srn CONUS, and
centered over the Lone Star State. This will be the dominant
feature in the forecast for the next 10 days or so, meaning little
rain and above-normal temperatures.
In the short term, vis sat imagery shows a healthy cu field
developing across the srn half or the CWA, and also over the NE
zones, as well. Return flow will result in a chance of convection
over the higher terrain this afternoon, but both the HRRR and NAM
Nest are hinting at development further east, as well. Mesoanalysis
places an axis of 2000-3000 J/kg SBCAPES running thru SE NM into the
SE Permian Basin, which may be what the HRRR/Nam Nest are homing in
on.
Otherwise, the ridge will slowly drift east and strengthen,
w/thicknesses increasing thru Friday, which looks to be the warmest
day this forecast. Isolated locations in the Permian Basin could
reach triple digits before the ridge moves further east to the Gulf
Coast states and thicknesses come down a bit. During this time, the
ridge may move far enough east to allow shortwaves to ridge up the
west side and nick SE NM, but chances of convection will be
isolated, if at all. Above-normal temps and below-normal rainfall
looks to persist.
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 74 96 74 99 / 10 0 0 0
Carlsbad 70 94 71 97 / 0 0 0 10
Dryden 74 97 74 99 / 0 0 0 0
Fort Stockton 71 94 71 98 / 0 0 0 0
Guadalupe Pass 67 88 67 91 / 10 0 0 10
Hobbs 68 92 68 95 / 10 0 0 0
Marfa 62 88 63 90 / 10 0 0 10
Midland Intl Airport 74 96 74 98 / 10 0 0 0
Odessa 74 95 74 98 / 10 0 0 0
Wink 73 97 73 100 / 0 0 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...None.
TX...None.
&&
$$
99/10/
Area Forecast Discussion
National Weather Service Marquette MI
732 PM EDT Tue Aug 21 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 359 PM EDT TUE AUG 21 2018
WV imagery and RAP analysis indicated that the prominent mid/upper
level shortwave trough had weakened and lifted northeast into
eastern Lower Michigan. At the surface, a tight pres gradient
persisted over eastern Upper Michigan and eastern Lake Superior
between a 1004 mb near London, Ontario and a 1025 mb high over ther
nrn plains. Vis loop and sfc obs showed clearing progressing through
Upper Michigan with mainly bkn high clouds over the west. Farther
upstream, mostly sunny skies with sct cu was observed over ne MN.
sct/isold shra have developed along the shoreline ne of Duluth near
of a secondary shrtwv trough axis but are expected to remain west of
IWD as they move to the southeast.
Tonight, expect the remaining low clouds over the east half to
slowly diminish from west to east this evening. Gusty north winds
over the east half of the U.P today will also quickly diminish this
evening and back w-nw and become light inland west overnight. Under
mostly clear skies, expect min temps near the lower end of guidance
in the mid to upper 40s over the interior west to the mid to upper
50s near the Great Lakes shorelines. However, since satellite trends
and mid level RH forecasts suggest that there may also be a period
of mid clouds into Upper Michigan btwn 06z-12z, confidence in the
lower end temps is still limited.
Wednesday, sfc and mid level ridging building toward the area will
bring mostly sunny skies to the region. The sunshine and 850 mb
temps rebounding into the 10C-12C range will support highs in the
mid 70s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 327 PM EDT TUE AUG 21 2018
Upper level ridging will be building into the Great Lakes Thursday,
with the surface high traversing into the Ohio Valley. Calm weather
will prevail through the day, with SW winds bringing temps back
above seasonal norms. A trough digging across the northern Plains
Thursday night will bring chances for relatively widespread rainfall
beginning out west just before sunrise Friday and increasing in
coverage during the day. A few PM rumbles of thunder cannot be ruled
out but the atmosphere should be relatively stable.
Chances for showers will continue overnight and into Saturday,
mainly across the east by the morning hours as the trough begins to
depart. Heights will rise a little and flow becomes nearly zonal
Sunday, but a weakening cold front may provide a touch of
convergence for a couple isolated showers or storms. Most locations
should remain dry, and temperatures look relatively warm once again.
Ridging will gradually build across the southeast early next week,
with a number of waves likely to ride up the western periphery,
bringing us back into a wet pattern. The next good chance for
showers and storms currently appears to be Monday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 732 PM EDT TUE AUG 21 2018
Conditions continue to improve as winds decrease this evening. No
flight restrictions are expected in the TAF period as a ridge of
high pressure settles over the area.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 359 PM EDT TUE AUG 21 2018
Gusty north winds of to around 25 knots over eastern Lake Superior
will dimininish quickly this evening as high pressure builds into
the region. Winds will then remain at or below 20 knots through the
rest of the week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Beach Hazards Statement until 8 PM EDT this evening for MIZ005-
006.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...KCW
AVIATION...Titus
MARINE...JLB
Area Forecast Discussion
National Weather Service Reno NV
305 PM PDT Tue Aug 21 2018
.SYNOPSIS...
Low pressure over far northern California and Nevada could bring
a few thunderstorms north of Gerlach this evening; otherwise, dry
weather will prevail for the next week. Temperatures near average
may cool to slightly below average early next week. Typical
afternoon and evening breezes are expected for the next few days.
&&
.SHORT TERM...
Looking at cameras around northeast California and northwest Nevada,
smoke from northern California fires remains evident from Cedar Pass
southeast to Gerlach, with haze (4-6 mile visibility) farther east
to Lovelock, Fallon, and Winnemucca. Thinner haze extends across
much of the rest of western Nevada and down into Mono County.
Through around sunset, low pressure will continue to bring a low-
end threat for showers and thunderstorms for northern Washoe and
eastern Modoc Counties, possibly working as far west as extreme
northeast Lassen County. The HRRR simulations have been indicating
a burst of northerly winds gusting to 30-40 mph over Pershing
County this evening as convective outflow combines with a north-
to-south pressure gradient (already producing north winds of 10-15
mph with gusts to 25 mph). With SPC mesoanalysis showing moderate
downdraft CAPE there, gusty winds to 40 mph are certainly possible
across Pershing County this evening IF showers and storms can
become a bit more widespread than they are now. This could throw
areas of blowing dust into the haze mix for west-central and
northwest NV.
Tonight and Wednesday, the upper low over far northern CA and NV
will exit into Idaho. With little cooling working into the region,
temperatures are expected to remain fairly similar (near/within 5
degrees of average) Wednesday through Friday. Modest afternoon
breezes will continue as thermal gradients persist between
California and eastern Nevada with an upper trough axis remaining
near the Pacific Northwest coast. -Snyder
.LONG TERM...Saturday through next Tuesday...
We are still on track to see a weather pattern shift for this
weekend into next week as a ridge of high pressure sets up just
south of the Gulf of Alaska and allows a trough to dig down into
the Pacific Northwest region. Recent model guidance suggests a
shallower trough, but still looks to create impacts for western
Nevada and the Sierra nonetheless.
Strong afternoon/evening winds and cooler temperatures will be the
highlights for Saturday onward throughout the region with minimal
chances for precipitation, mainly for northern portions of Washoe
and Lassen counties. Afternoon westerly wind gusts will be around
20-30 mph on Saturday. Sunday still looks to be the day with the
strongest winds with potential gusts in the 25-35 mph range. This
will increase the concerns for critical fire weather conditions as
it will be windy and seasonable dry with afternoon RH values
forecast below 15% for many locations.
As for temperatures, daily highs will be near-normal for this
time of year, which means around 90 degrees for the western Nevada
valleys and upper 70s/low 80s for lower elevations in the Sierra.
It will feel like a significant cool down compared to the daily
highs we have been experiencing these past 50+ days. With that
said, there is high forecast confidence that we have seen our last
days of triple digit temperatures for this year with no clear
signs of high pressure building back into the region anytime soon.
-LaGuardia
&&
.AVIATION...
Mainly VFR conditions for this afternoon/evening with low pressure
sitting just towards the northeast over Idaho. Isolated showers
and thunderstorms have been ongoing this afternoon for extreme
northern portions of Lassen & Washoe counties with the main threat
possible outflow gusts of 40 kts.
Zephyr flow will continue for the next few days with afternoon
westerly winds in the 10-15 knot range with gusts of up to 25 kts
dropping off around 02-03Z for KTVL/KTRK and 05Z for KRNO/KCXP/KMMH.
Impacts from haze and smoke will also continue due to the ongoing
fire activity in California and the Pacific NW region. Slantwise
visibility reductions are expected from Lassen County eastward into
Pershing and Churchill counties and in portions of Alpine and Mono
counties. -LaGuardia
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Riverton WY
245 PM MDT Tue Aug 21 2018
.SHORT TERM...(This evening through Wednesday)
Issued at 143 PM MDT Tue Aug 21 2018
Currently, scattered thunderstorms are tracking northeast across
Southeast Sweetwater County in response to a vort max tracking
across that area. Good mixed layer cape exists over this area.
The HRRR is showing a thunderstorm tracking northeast across
Sweetwater County during the mid evening hours, but, other than
that, most of the convection for the rest of today will be
relegated to Southern Wyoming. Right rear quad jet dynamics will
also come into play there.
For Wednesday, much more numerous, widespread thunderstorms are
expected. Much of the western half of the CWA is under a marginal
risk for Wednesday. A larger area of cape and better lifted
indices are progged to track north across the CWA during the day
Wednesday in asctn with the closed low centered over Idaho that
is progged to track slowly northeast toward the Northern Rockies,
placing us in the increasingly difluent west southwest flow. The
asct trouphpa will occur around 12Z Thursday. The gradient will
increase around the base of this passing trough making Thursday
likely the windiest day of the week, coupled with the low RHs,
making Thursday a good candidate for a critical fire weather day.
Behind this trough, the weather will become warmer and drier
Thursday and Friday. The Euro actually tracks a second weaker
shortwave across the CWA 06Z Friday but this soln is the outlier
amongst the GFS and the Canadian, which are preferred as these
models resemble the pattern as of late. The RH will steadily drop
from the mid to upper teens at the lower elevations in areas east
of the Divide, as well as in Sweetwater County, Thursday, to the
mid teens Friday, and to the low to mid teens Saturday, with this
next trough remaining to our west and north. Highs should reach
the upper 80s in many locations by Friday east of the divide,
and 70s in the far west valleys.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 143 PM MDT Tue Aug 21 2018
Large scale pattern shows amplification of the ern Pacific ridge
with the mean trough retrograding towards the Rockies. We will
likely see a couple shortwaves skim across the north through the
upcoming weekend before a much stronger and cooler/colder trough
settles in near the end of this period (Monday night and Tuesday).
This much colder system is currently just east of Kamchatka and
stays at a fairly high latitude as it track east and the ridge
builds up behind it over the ern Pac as another strong upper low
west of the dateline aids in pumping up the ern Pac ridge allowing
our system to dig se over us next week. This system will likely
have enough cold air to produce a swath of snow across the
northern mountains above 9000 to 10000 feet early next week. Until
then, we deal with probably three passing shortwaves Friday
night, Saturday night and a stronger one Sunday night. This last
one is farther south and has a better potential for a swath of
showers and thunderstorms with it. Fire weather may be a bigger
concern through the weekend with a generally dry and warm sw flow
and breezy to windy conds.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 143 PM MDT Tue Aug 21 2018
A few thunderstorms will move across the southwest and far south
through tonight with local mvfr vsbys in rain. The best chance for
this will be at KRKS with a lesser chance at KBPI and KPNA.
Patchy late night fog and MVFR conds are possible around KBPI,
KPNA and KCOD between 10z and 15z Wed. Wednesday afternoon and
evening will see a better chance of thunderstorms across much of
the area. Some of these could be quite strong.
&&
.FIRE WEATHER...
Issued AT 143 PM MDT Tue Aug 21 2018
An upper level system will bring colder temperatures, higher
relative humidity, clouds and showers with isolated thunderstorms
during the remainder of this afternoon and evening.
Thunderstorms will be a bit more numerous during the rest of today
across southern portions of 279. More numerous thunderstorms
are expected Wednesday everywhere. As the system leaves the area
Wednesday expect a return to dry conditions Thursday through
Saturday. Gusty winds from Sweetwater to Natrona Counties could
bring near critical conditions on Thursday.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Lipson
LONG TERM...Skrbac
AVIATION...Skrbac
FIRE WEATHER...Lipson
Area Forecast Discussion
National Weather Service Blacksburg VA
1015 PM EDT Tue Aug 21 2018
.SYNOPSIS...
Low pressure moving into the Great Lakes will push a slow moving
cold front through the region late tonight and tomorrow, and
bring strong thunderstorms to the Appalachians and central mid
Atlantic region. High pressure will then build in from the
midwest and bring much more pleasant weather to the region for
the end of the workweek and into the weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1015 PM EDT Tuesday...
The cold front has advanced to eastern West Virginia and western
North Carolina as of 10PM. Air mass over the Virginia and North
Carolina foothills and piedmont ahead of the front still has
enough instability and forcing to maintain a band of showers
and thunderstorms across southern Virginia and northern North
Carolina. Only light isolated to scattered showers in the
mountains behind the front overnight.
The front will ever so slowly work its way east across the
region Wednesday, shifting winds around to the northwest. With
deep synoptic moisture this will develop upslope clouds and some
sprinkles/drizzle overnight along and west of the Blue Ridge
with some downsloping clearing to the east.
The low level wind field will amplify and start some gusty
conditions along the hilltops overnight. The winds will mix down
to lower elevations as steep low level lapse rates develop
tomorrow morning, making conditions a bit gusty through the
afternoon. Instability appears tall and skinny on model
soundings tomorrow but lapse rates are steepening and will make
for some isolated showers/thunder tomorrow afternoon, especially
east of the Ridge.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 230 PM EDT Tuesday...
A much quieter and pleasant end to the workweek as a large high
pressure builds into the northern mid-Atlantic region and by Friday
into southern New England. The main highlight in this period is the
much more comfortable humidity levels and period of cooler than
normal temperatures.
Each day should feature sizable diurnal ranges given dry air both
surface (dewpoints in the 40s to mid 50s) and aloft as well as
largely clear skies. Our western counties may see some high-altitude
haziness to skies as northwest flow aloft may transport the eastern
extent of Canadian/western CONUS wildfire smoke well aloft. There
should still be enough of a northwesterly gradient wind to preclude
overnight radiation fog development Wednesday night, but this
gradient will slacken early Thursday allowing for lighter northwest
winds during the day. Prospect for nighttime radiation fog may be
greater Thursday and Friday nights. With 850 mb temperatures around
the upper single digits to low teens Celsius supporting highs in the
70s and lows in the mid 40s to 50s, conditions late this week may
draw some comparison to early fall. Indeed, forecast 850 mb
temperatures are more ordinarily observed around early October per
the SPC sounding climatology. Only small change expected Friday is
that the winds should shift to an easterly component.
Overall forecast confidence is high, though is moderate on
nighttime fog potential.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 230 PM EDT Tuesday...
Our stretch of cooler than normal temperatures and low humidity
levels is short-lived, as a large heat ridge builds eastward for the
weekend. 850 mb temperatures rise to around +18C by the weekend with
humidity levels also on the rise. Thus look for a return to more
summerlike weather by the weekend and into early next week. Saturday
looks dry but a northern-stream upper-level trough may provide
enough of a weakness in subsidence to produce a greater coverage of
thunderstorms on Sunday. While possible, it`s still early to say
with any level of certainty if any may become strong on Sunday.
Temperatures should trend more typical of midsummer in this period,
trending above normal by early next week.
Overall forecast confidence is moderate in this period.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
As of 735 PM EDT Tuesday...
Several narrow bands of showers and thunderstorms will cross the
Mid Atlantic region this evening producing a brief period of
LIFR visibility due to heavy rain and wind gusts of 20 to 30
knots. Thunderstorms will be just moving east of KROA at the
beginning of the TAF forecast period. HRRR and WRF guidance
suggest the bulk of the thunderstorms and cold front will be
well east of KDAN and KLYH by 09Z/5AM. High confidence there
will be a lull in precipitation after the frontal passage.
The cold front will shift the winds around to the northwest.
This will develop upslope MVFR/IFR conditions west of the Blue
Ridge with a trend to VFR conditions east. Expect enough wind
flow to keep fog formation in check but low level moisture is
abundant and cigs west of the Blue Ridge will likely be IFR to
LIFR and expect some sprinkles/drizzle as well, especially at
KBLF. Any subtle changes in timing will complicate fog/stratus
forecast tonight so this will be monitored closely and
confidence is medium to low.
Conditions will improve after daybreak Wednesday. The low level
wind field will amplify and start some gusty conditions along
the hilltops overnight. Expect steep low level lapse rates to
yield a well mixed boundary layer and allow low level winds to
mix down and make for some gusty conditions all locations
through Wednesday afternoon. Instability appears tall and skinny
on model soundings but lapse rates are steepening and will make
for some isolated showers/thunder Wednesday afternoon,
especially east of the Blue Ridge. Expecting sparse coverage so
have left out of the TAFs for now.
Extended Discussion...
High pressure will be overhead by Thursday. VFR conditions are
expected with this cooler and drier air mass through Friday.
MVFR to IFR fog is possible for a few hours each night along and
near the typical river valleys, especially west of the Blue
Ridge.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...MBS
NEAR TERM...AMS/MBS
SHORT TERM...AL
LONG TERM...AL
AVIATION...AMS/MBS/RAB
Area Forecast Discussion
National Weather Service Las Vegas NV
747 PM PDT Tue Aug 21 2018
.SYNOPSIS...Expect decreasing winds overnight with afternoon breezes
on Wednesday. Monsoon moisture will remain in place through Thursday
over Mohave County where the best chance for thunderstorms will
continue. Dry conditions with seasonal temperatures on Friday and
over the weekend.
&&
.UPDATE...A sharp moisture/instability gradient exists generally
along and east of a line from Baker, CA - Boulder City, NV - St.
George, UT. Isolated showers/thunderstorms that developed across
southern Mohave, eastern San Bernardino and southeast Clark Counties
will continue to be on the downward trend over the next hour. Most
active area today and forecast to continue overnight will be across
northern Mohave County. HRRR and other convective allowing models
suggest several narrow lines of convection will continue overnight.
Drier air associated with the Pacific Northwest trough has brought
surface dewpoints down into the teens and 20s across Inyo and
Esmeralda Counties and 30s-low 40s across Nye and western San
Bernardino County. The Las Vegas Valley dipped into the mid 40s this
afternoon. However, dewpoints creeping up a bit with sunset as the
valley lies near the previously mentioned moisture boundary.
For Wednesday. Sharp moisture/instability gradient forecast to
remain intact nearly along a similar line or slightly further
eastward. The current forecast for isolated to scattered
showers/thunderstorms primarily across Mohave County looks fine.
&&
.NEAR TERM...through the afternoon.
Visible satellite imagery shows an obvious counter clockwise spin
near Nogales AZ moving north. SPC mesoanalysis shows moisture axis
extending from the lower Colorado River Valley up through Mohave
County where 850mb moisture transport vectors indicate the best
potential for storms producing heavy rain. RAP has moderate to
strong instability focused across Mohave County with the area of
highest CAPE and lowest LIs lifting north through the afternoon.
Otherwise, there is nothing obvious in current observational data
that would indicate other areas that would be favorable for near
term development. 130 pm wind gusts across the region are in the 25-
35 mph range which remains under advisory levels. Temperatures
overall are running 3-6 degrees cooler than yesterday, in line with
the forecast.
Tonight through Friday...
Once daytime heating is lost at sunset, storm development should
dissolve with no other driver in place to maintain convection into
the overnight hours. The moisture/instability gradient remains over
essentially the same area (from the Mojave Preserve to Las Vegas to
Mesquite) Wednesday and Thursday however, the region of deeper
moisture and better instability is further east. Thunderstorm
chances linger over primarily Mohave County Wednesday and Thursday
afternoon before mainly dry conditions return for Friday.
Temperatures will be near to slightly above normal through Friday.
.LONG TERM....Saturday through Tuesday.
Little change in the long term forecast as southwest flow will bring
in drier air across much of the region and keep monsoonal moisture
confined to northwest AZ through the weekend. By Sunday, the medium
range models bring in a trough across the NW states which will
result in increased southwest winds. By Monday, models are in pretty
good agreement and dig this trough further into the Great Basin
region through Tuesday. This trough will likely scour out the
remaining low grade moisture over northwest AZ and bring gusty to
windy southwest winds across the region. As of now, these winds look
to be below wind advisory criteria. Otherwise, expect mostly clear
skies and near or slightly above normal temperatures through the
period.
&&
.AVIATION...For McCarran...Breezy southeast winds are expected to
continue through the rest of the day, eventually subsiding overnight
tonight. Peak winds gusts of 30-35 kts are possible between the 21-
04Z time frame before beginning to subside and the potential for
gusts up to 25 kts may linger as late as 08Z tonight. Models
continue to produce storms this afternoon but latest runs keep most
activity east of the KLAS terminal. So left VCTS out of the TAF with
this package as confidence is still low for terminal impacts.
However, this is not to say that an isolated cell is out of the
question this evening. If so, erratic outflow winds will be the main
impact.
For the rest of southern Nevada, northwest Arizona and southeast
California...Gusty southerly winds will begin to overspread the
region through the rest of the morning and into the afternoon.
Strongest southwest winds are expected between 20-02Z later this
afternoon and evening with gusts to 25-35 kts. Thereafter, winds
should steadily decrease with gusts dropping off by 06-07Z tonight
and then should return to diurnal winds by the early morning. Models
develop isolated to scattered storms late this evening as far west
as the I-15 corridor and best chances for VCTS should be for KEED
and KIFP.
&&
.FIRE WEATHER...Isolated to scattered thunderstorms over Mohave
County Wednesday and Thursday otherwise southwest winds with gusts
to around 25 mph on Wednesday. Relative humidity under 20 percent
across much of the region on Wednesday except in eastern San
Bernardino, southern Clark and Mohave counties. Drier conditions
push into all areas expect Mohave County on Thursday. Mainly dry
conditions area wide Friday and over the weekend.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Pierce
SHORT TERM...Salmen
AVIATION...Boucher
LONG TERM...Kryston
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