Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/12/22
Area Forecast Discussion
National Weather Service Boise ID
822 PM MDT Sun Sep 11 2022
.DISCUSSION...The upper level ridge will migrate east of our area
Monday night, allowing an upper level trough to approach from the
coast. Southerly flow ahead of the trough will transport moist
and unstable air north from the Desert Southwest and Great Basin.
This will lead to an increasing chance of showers and
thunderstorms Monday night and Tuesday. An added benefit will be a
decrease in smoke. The next trough will bring more showers
Wednesday afternoon through Thursday. This pattern will keep
temperatures near normal
&&
.AVIATION...Smoke reducing visibility, with increasing clouds
throughout the day. Isolated showers possible late over eastern
Oregon. Surface winds: variable 5-10 kt. Winds aloft at 10k feet
MSL: Southwest 15 to 25 knots.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Tuesday night...Smoke and poor air
quality will continue in all areas through at least Monday night
as an upper ridge moves slowly eastward and out of our area.
Latest HRRR smoke model clears the smoke out of western Oregon
later Monday night as a Pacific upper trough moves inland.
Improvement should reach eastern Oregon Tuesday morning and
possibly western Idaho Tuesday afternoon, although HRRR doesn`t
go out that far. The upper trough will bring a chance of showers
to Harney County Monday, then a slight chance of showers and
thunderstorms with gusty winds to most of southern Idaho Monday
night. The Treasure Valley northward will probably miss out until
Tuesday. Even more likely to get rain on Tuesday will be south-
central Idaho and the Camas Prairie where moisture from the
remnants of tropical storm Kay will be included. Monday will
still be warm, especially on the Idaho side. Tuesday will be
cooler, partly due to the incoming trough, but also due to clouds
and showers, especially in south-central Idaho. Winds will be
light except near thunderstorms, mainly Monday evening along and
north of the Nevada border,
LONG TERM...Wednesday through Sunday...Unsettled weather will
continue through Friday as a series of passing shortwaves
interacts with monsoonal moisture. Models continue to focus
heavier precipitation across the Idaho mountain zones while
showing drier conditions across the basins of southeast Oregon.
Forecast confidence beyond Saturday is minimal, as the models
differ significantly on the handling of a trough in the Gulf of
Alaska Saturday and Sunday.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
www.weather.gov/Boise
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise
DISCUSSION...JT
AVIATION.....MC
PREV SHORT TERM...LC
PREV LONG TERM....KA
Area Forecast Discussion
National Weather Service Boston/Norton MA
1010 PM EDT Sun Sep 11 2022
.SYNOPSIS...
A warm front approaching from the south will bring showers to
southern New England tonight, especially near the south coast.
Showers exit the coast Monday morning, otherwise mainly dry
weather with warm and humid conditions. Scattered showers and
thunderstorms expected across southern New England on Tuesday
as a cold front moves into the region. A few strong to severe
storms are possible along with heavy rainfall. Showers clear
out late Tuesday and then high pressure builds in mid-week and
controls the region with drier and cooler temperatures for
late in the week followed by seasonably warm weather next
weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Made some tweaks to rainfall chances overnight based on regional
radar data and latest runs of the HRRR and NationalBlend. Just
looking like light showers or sprinkles overnight. Lower risk
for isolated thunderstorms. Thinking that threat has shifted
farther south, but will continue to monitor. Minor tweaks to
temperatures, too.
630 PM Update
KBOX radar currently showing some light returns over southern
New England. Cloud bases are relatively high, thus most of these
returns are only making it to the ground as sprinkles or light
rain. Still expecting to see showers expand in coverage over the
south coast overnight, where some moderate rainfall may be
possible. No big adjustments made with this update other than
bringing the near-term in line with the latest obs.
Previous Discussion
Weak shortwave and higher PWAT airmass advecting into SNE
resulting in showers moving across SNE, but presence of dry air
in the low levels eroding a lot of the precip with just
sprinkles falling. Low levels moisten up from west to east
tonight, mainly south of the Pike which will lead to an
increasing risk of showers.
Warm front approaches from the south tonight and gets close to
the south coast toward 12z but likely remains just to the south
as a wave develops on the front. Increasing PWATs tonight,
approaching 2 inches along the south coast along with leading
edge of higher low level theta-e air moving northward into SNE.
Instability is confined to the south where scattered convection
will develop tonight. The forecast challenge is how far north do
the heavier showers get. 3km NAM, HRRR and NSSL-WRF are most
aggressive bringing some heavier rain to the immediate south
coast aided by a modest low level jet. However, WRF-ARW/FV3 and
global models keep heavier rainfall to the south. We are
confident in a period of showers developing along the south
coast later this evening and overnight with some of these
showers possibly reaching the Mass Pike, but likely remaining
dry to the north. Best chance of heavier rain will be over the
Islands but will have to see where warm front sets up. Any
northward trend will increase heavy rain potential along the
south coast. Best chance of any t-storms will be over the ocean
to perhaps the Islands late tonight and Mon morning.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Monday...
Showers and isolated thunder will exit the SE New Eng coast
during the morning as mid level drying moves in behind departing
frontal wave. The rest of the day should feature mostly dry
weather as upper level ridging builds over New Eng. Clouds will
dominate near the south coast as low level moisture is slow to
depart with most sunshine across northern MA. Highs will be in
the upper 70s to lower 80s, warmest across NE MA. It will be a
humid airmass with dewpoints climbing to mid 60s to around 70
near the south coast.
Monday night...
Deep closed low lifts NE into the eastern Lakes as attendant
cold front moves W to E across New York. All the CAMs are
indicating a cluster of showers and isolated thunder moving into
western New Eng overnight within a deep moisture plume.
Instability is marginal but PWATs around 1.75" so potential for
locally heavy rainfall, but better chance will be to the west
where forcing for ascent is strongest. It will be a warm and
humid night with lows mid/upper 60s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Tuesday
Fairly robust short-wave over The Great Lakes will be lifting
northeast over NY on Tuesday. As this occurs an associated
surface low will move over the northeast and bring the
opportunity for some substantial precipitation. Deep southwest
flow ahead of this system will surge PWATs to over 1.7 inches
which is well above normal for early September in New England.
Model guidance is generous with instability with recent model
CAPE values coming in between 500 and 1000 J/kg. With fairly
strong deep- layer shear in the 6 km layer, there will be the
potential for organized thunderstorm growth. One limiting factor
is expected to be mid-level lapse rates which are expected to
be unimpressive at this time. Nonetheless we can`t rule out a
few strong storms developing Tuesday afternoon. SPC currently
has the region highlighted in a marginal risk for severe storms.
Additionally, WPC has the region in a marginal risk for
excessive rainfall. Given the synoptic setup and expected
instability, heavy downpours will be likely with a few showers
or storms. The region is still suffering from substantial
rainfall deficits this year, so any rainfall would be welcome.
Which areas receive the most rainfall will depend heavily on
the storm track. These details are best resolved by Hi-Res
models which are still a bit out of range at this time.
Therefore, have leaned on NBM guidance for rain in the meantime
which gives most of the western areas of southern New England
between 0.5 and 1 inches of rain. Will have a better idea of
where the locally higher amounts may reside in the next 24
hours.
Wednesday through Sunday
As showers and storms exit the region Tuesday evening, northwest
flow ushers cooler/drier air over the region. This will bring
the onset of extended dry weather. This period starts with above
normal temperatures on Wednesday with highs in the upper 70s to
low 80s. By Wednesday night however, strong cold air advection
aloft will support more fall like temperatures through Friday
with daily highs/lows in the 60s and 40s/50s respectively.
Temperatures gradually warm up next weekend as high pressure
shifts east and west/southwest flow prevails over the region.
No precipitation expected during this period.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight...Moderate confidence.
VFR to start, with cigs lowering to MVFR from W to E after
midnight. Areas of IFR possible towards daybreak from the CT
valley to the RI coast. Scattered to numerous showers
developing, mainly south of the Pike and especially near the
south coast where locally heavy showers possible after
midnight.
Monday...Moderate confidence.
MVFR/IFR south of the Pike improving to VFR in the afternoon,
but MVFR persisting Cape/Islands. VFR north of the Pike. Showers
exiting the south coast in the morning with an isolated t-storm
possible.
Monday night...Moderate confidence.
VFR trending to MVFR after midnight with pockets of IFR
possible. Scattered showers and an isolated t-storm possible in
western New Eng overnight.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...Moderate confidence in TAF. Some uncertainty
regarding how low ceilings get overnight. MVFR likely but lower
confidence in IFR developing.
Outlook /Tuesday through Friday/...
Tuesday: Mainly MVFR, with local IFR possible. Chance SHRA,
isolated TSRA.
Tuesday Night: Mainly VFR, with local MVFR possible. Breezy.
Slight chance SHRA.
Wednesday through Thursday Night: VFR. Breezy.
Friday: VFR.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Monday night...High confidence.
Nearby high pressure will result in relatively light winds
across the waters through Monday night. Small Craft Advisories
remain in effect for rough seas on outer waters due to
lingering swell from what was once Hurricane Earl. Seas
expected to gradually diminish below 5 ft tonight into Monday.
Outlook /Tuesday through Friday/...
Tuesday: Winds less than 25 kt. Chance of rain showers,
isolated thunderstorms.
Tuesday Night through Wednesday: Winds less than 25 kt. Areas
of seas approaching 5 ft.
Wednesday Night through Friday: Winds less than 25 kt. Seas
locally approaching 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Monday for ANZ250.
Small Craft Advisory until 7 PM EDT Monday for ANZ254-255.
Small Craft Advisory until 2 AM EDT Monday for ANZ256.
&&
$$
SYNOPSIS...KJC/RM
NEAR TERM...Belk/RM
SHORT TERM...KJC
LONG TERM...RM
AVIATION...Belk/KJC/RM
MARINE...KJC/RM
Area Forecast Discussion
National Weather Service Dodge City KS
641 PM CDT Sun Sep 11 2022
...Updated Aviation Section...
.SHORT TERM...(This evening through Monday)
Issued at 1235 PM CDT Sun Sep 11 2022
Water vapor satellite imagery and RAP upper air analysis at 1715Z
indicates and upper level ridge is located over the Great Basin,
with a strong cut-off low over the Midwest. Short range guidance
is in agreement suggesting these features will move slowly east
through the period while the ridge dampens. At the surface, high
pressure will be maintained over the central and southern plains
in the wake of the cold frontal passage Friday evening, and
promote an absolutely gorgeous day across southwest KS with clear
skies, light winds, and afternoon highs in the mid/upper 70s.
Overnight Sunday, southwest KS will remain quiet as radiational
cooling is optimized, with lows in the upper 40s/low 50s.
Unfortunately, the cool weather will not last into the work week
as summer comes roaring back to the central plains. Latest runs
of the ECMWF/GFS forecast 850-mb temperatures will increase around
5-8 degrees C by Monday afternoon, which will translate to surface
high temperatures in the upper 80s/near 90 under persistent clear
skies and light south-southwest winds.
.LONG TERM...(Monday night through Sunday)
Issued at 151 PM CDT Sun Sep 11 2022
Monday night will be the last relatively cool night for our area,
as continued clear skies and light winds aid temperatures in
dropping into the low to upper 50s by Tuesday morning. Daytime
Tuesday, medium range guidance agrees the upper level ridge will
weaken and eject into the High Plains as it is replaced by broad
longwave troughing out west, and 850-mb temperatures will warm
another 3-4 degrees C in response. This will force afternoon highs
back into the low to mid 90s for southwest KS.
A modicum of relief is possible Wednesday as a shortwave trough
ejects into the central plains, carrying with it enough lift to
support mostly cloudy skies and perhaps a slight chance of
precipitation favoring the western zones. These factors may shave
a few degrees off afternoon highs, but still expect temperatures
maxing out in the upper 80s near the KS/CO border to mid 90s near
central KS. Thursday through the end of the period, guidance
solutions begin to diverge regarding key synoptic features, as the
ECMWF maintains weak longwave troughing over the western CONUS and
the GFS builds another cut-off ridge northward out of the southern
plains. As a result, forecast confidence in the latter half of the
long term period is low, especially surrounding any slight
precipitation chances. However, reasonable confidence still exists
in above normal temperatures through this time frame, as
afternoon highs in the mid to upper 90s appears more likely than
not.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 639 PM CDT Sun Sep 11 2022
Aviation weather will be about as tranquil as it can get through
this TAF period. Surface high pressure will slowly pull away from
southern and western Kansas tonight into Monday, and while the
winds will eventually become southerly/southwesterly on Monday,
they will remain fairly light. There will be a 2 to 4 hour period
of winds in the 11 to 14 knot range, but the prevailing wind speed
through this TAF period will be 7 knots or less.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 50 87 57 94 / 0 0 0 0
GCK 48 86 53 91 / 0 0 0 0
EHA 50 89 55 93 / 0 0 0 0
LBL 50 89 56 94 / 0 0 0 0
HYS 47 86 54 92 / 0 0 0 0
P28 51 87 59 94 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Springer
LONG TERM...Springer
AVIATION...Umscheid
Area Forecast Discussion
National Weather Service Gray ME
1042 PM EDT Sun Sep 11 2022
.SYNOPSIS...
High pressure along with elevated surf and rip risk remain the
story through this evening. Our attention then turns to a
trough of low pressure bringing rain and possible thunder to the
region through the middle of the week. A cooler northwest wind
comes behind this system to close out the week.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Update...
Mid and high level moisture continues to cross the forecast
area late this evening. There are a few sprinkles or isolated
showers as well which is depicted by the latest HRRR and Namnest
solutions. However, much of this moisture continues to hit a
wall with a dry layer around H8 on the latest 00Z GYX sounding.
Have adjusted pops slightly once again and have kept some
patchy late night fog in the forecast despite the cloud cover.
Temperatures remain relatively warm as of 02Z but should drop
into the 50s to lower 60s by morning.
Prev Disc...
A few light sprinkles and rain showers continue over
southernmost New Hampshire per latest imagery. However, most of
this precipitation is not reaching the ground due to the very
dry layer at around 800 mb per latest GYX sounding.
Have made minor adjustments to the pops for this evening with
the latest HRRR bringing a few more sprinkles across western and
southern portions of the forecast area overnight. Also, very
minor changes were made temperatures, dew points and winds for
the near term portion of the forecast.
Prev Disc...
High pressure briefly erodes tonight as a weak trough crosses
aloft...offering a chance for a few very light showers across
the north, but mostly bringing cloudy conditions to the region.
Latest observed and modeled soundings show a fairly deep layer
of dry air through the mid-levels, so while I`m not too excited
over rain tonight (which may be little more than a few
sprinkles) cloud bases will probably remain high enough to still
allow for some valley fog formation as temperatures cool into
the 50s to low-60s.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
High pressure noses back into the region on Monday with a fair
weather day expected. Some cloudiness from overnight will
dissipate or move east and out of the region, which allows high
temperatures near 80 for a greater portion of the area on Monday
versus what we saw today. Dew points will be similar to today,
in the 60s for the most part, so it will still feel a bit
sticky. Clouds will be on the increase again late in the day.
Winds through the column will be quite weak once again, as
northern New England finds itself in a bit of a col between low
pressure well out over the north Atlantic and another upstream
over the Great Lakes region. Thus, winds will be light and
variable at the surface on Monday but will turn southeasterly
along the coast with the seabreeze... then a broader southerly
to southeast flow will take same Monday night as low pressure
approaches from the west. As temperatures cool into the 50s and
60s overnight, cloud bases, while lowering, should be high
enough to allow some valley fog to form especially in the
Connecticut River Valley. A few light showers may break out, and
some marine stratus or fog may develop and push onshore, by
Tuesday morning but most of this holds off until the day on
Tuesday.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Summary: A closed low aloft will pass through the area over the
first part of the week bringing an occluded low and
showers/thunderstorms to the area Tuesday. Instability is
uncertain, however some stronger thunderstorms will be possible.
Cooler, drier air moves in behind the low bringing below
average temperatures for the end of the week before gradually
warming through the weekend.
Details: An occluded low moves into the area Tuesday bringing
several periods of rainfall to the area as it passes. There is
still a marginal level of uncertainty in the the strength and track
of this low. Most of the uncertainty stems from whether or not
a coastal low will develop over the Gulf of Maine. Some GEFS
ensemble members suggest a coastal low development which the
deterministic run and the NAM also hint at. Before latching onto
this I would like to wait for a few more NAM runs to be sure
this trend is realistic. The triple point of the cold, warm, and
occluded fronts looks to track right across the CWA with SE
flow setting up early Tuesday bringing moisture into the coastal
and interior areas before swinging around to the west
overnight. ECMWF and CMC solutions which don`t develop the
coastal low advect the moisture further inland where the GFS and
NAM show most of the moisture available for instability
remaining mostly near the coast and western NH. Showers look to
start Tuesday afternoon along the occluded/warm front with
moderate instability through southern NH and into southwestern
Maine. SPC currently has a marginal risk sitting just to the
south over Massachusetts with our CWA in the general
thunderstorm category. Given the proximity to the marginal risk
as well as 30-40 kts of shear and 1000-1500 J of CAPE across
southern NH, thunderstorms will be likely with some stronger
storms possible. The degree of instability and storm coverage
will be better determined over the coming days as more CAMs
cover the time range.
Dry air starts moving in from the southwest on Wednesday as the
dry slot starts creeping in. Some lingering upslope showers
will be possible as the low makes its way out with some residual
moisture wrapped around the low. These showers will remain
mostly in the mountains and northern areas before clearing up
overnight Wednesday. Cooler, drier air fully sets in Thursday
with lows dropping into the 40s to low 50s Wednesday night and
rising into the upper 50s north of the mountains to near 70
along the coast Thursday afternoon. Temperatures will remain
cool and clear for the end of the work week before zonal flow
starts gradually warming temperatures for the weekend.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Short Term...VFR clouds decks will stream overhead with a
minimal threat of a sprinkle through tonight... and another
round of valley fog at the usual terminals including KHIE and
KLEB. VFR prevails on Monday as well with light and variable
flow, turning onshore for coastal terminals during the
afternoon. Ceilings will begin to steadily lower as a storm
system enters from the west Monday night, but the best chance
for significant restrictions comes with potential fog
development in valley locations and perhaps coming into the
coast.
Long Term...Low pressure will bring showers and possible
thunderstorms to the area Tuesday. Onshore flow could bring
coastal fog Tuesday morning. Winds will shift around to the west
Wednesday with VFR conditions returning through the weekend.
Some upslope showers will be possible in northern terminals
throughout the day Wednesday.
&&
.MARINE...
Short Term...A ridge of high pressure extending northward into
the Gulf of Maine shifts eastward and slightly degrades tonight
into tomorrow, which will allow westerly flow over the waters
(except for an afternoon seabreeze) to gradually turn onshore
Monday night. Some fog may develop in onshore flow early Tuesday
morning. We`ll also see a gradual easing of the long period
swell from distant Hurricane Earl, which will continue to slowly fall
below 5 ft overnight and to around or below 3 ft Monday into
Monday night.
Long Term...Low pressure passing through the area will bring
onshore winds and coastal fog early Tuesday before showers pass
through Tuesday afternoon and evening. Winds shift to offshore
Wednesday and Thursday, becoming gusty with relatively strong
cold air advection over the Gulf of Maine. A SCA may be needed,
but expect winds to remain right around 25 kt. Winds and seas
subside thereafter as high pressure gradually builds towards the
waters.
&&
.TIDES/COASTAL FLOODING...
Swells are gradually diminishing as distant Earl tracks east
and away from North America, and astronomical tides are trending
down from their monthly maximum seen earlier this weekend.
Therefore the threat for minor pockets coastal impacts
including erosion and splash-over, along with the elevated rip
current risk and rough surf, is diminishing.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
NEAR/SHORT TERM...Cannon
LONG TERM...Thunberg
Area Forecast Discussion
National Weather Service Wilmington NC
711 PM EDT Sun Sep 11 2022
.SYNOPSIS...
Muggy conditions and scattered showers will be around until a
cold front pushes the moisture offshore on Tuesday. Thereafter
temperatures will warm and only very isolated sea breeze
thunderstorms will return.
&&
.UPDATE...
Showers and thunderstorms continue to fire along a convergence
axis about 40 miles inland from the coast. Current activity
between Florence, SC and the beach will probably continue
through 10pm before gradually dissipating. HRRR and HREF
ensembles suggest convective risk will then shift to the South
Carolina coastal waters with a new cluster of showers/storms
developing and moving northeastward after midnight, potentially
scraping by Myrtle Beach on its way toward dawn Cape Fear
impact.
Myrtle Beach (MYR) recorded dewpoint temperatures as high as 81
earlier today. Most coastal sites have had an hour or two of 79
or 80 degree dewpoints today. We`re trying to search historic
data to see if this is the latest in the year for such high
dewpoints.
&&
.NEAR TERM /THROUGH MONDAY/...
500 mb low over eastern IA this afternoon will move eastward across
northern IL/IN through Monday. Mid-level ridge axis off the SE
CONUS will transition eastward as well, with the net result being a
continued plume of Gulf moisture streaming NEwd across the forecast
area through the period. Weak impulses embedded in the SW flow aloft
will warrant the inclusion of 20-40% PoPs through the period, with
latest HRRR suggesting convection will wane after 02Z this evening.
The stage appears well set for areas of dense fog to develop
overnight, and will have to monitor for the possible need for a
Dense Fog Advisory. Monday should evolve much like today. Once fog
and low clouds burn off mid-morning, temps will rise into an 85-
88 range, with scattered showers/tstms developing by early afternoon.
Additionally, the next several high tide cycles are expected to
result in minor coastal flooding along the lower Cape Fear River,
although the beachfronts should stay below flooding thresholds. Will
issue a Coastal Flood Advisory for the lower Cape Fear centered
around tonights high tide...which is around 11:30 pm.
&&
.SHORT TERM /MONDAY NIGHT/...
Shower and storm coverage will be at their normal nocturnal minimum
but not dissipate altogether due to the approach of a cold front. This
boundary will push moisture offshore as Tuesday progresses. Models
have trended a bit faster and rain chances no longer linger at the
coast. Some less oppressive dewpoints will also advect in from the
NW, most pronounced as you head further inland. The new airmass will
allow for a more seasonably cool Tuesday night.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Even though the base of the formerly phased trough lingers Wednesday
moisture appears to remain too paltry for meaningful rain chances.
Of the op models the GFS remains alone in its depiction of this weak
feature developing a healthy surface low and a heavy coastal rain
event. Have kept the previous forecast ideas in that the latter half
of the week may be more typical of late Summer with above normal
temperatures and only isolated diurnal thunderstorms along the
immediate coast, moisture remaining to shallow further inland.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
An area of showers and embedded thunderstorms between KFLO and
the coastline should continue for a few more hours before
dissipating late this evening. VFR conditions should continue.
Convective risk could increase along the South Carolina coast
late tonight after 06-08z, potentially affecting KMYR and KCRE.
There are some model indications convection could reach KILM
before 12z. Inland, a moderate risk of low stratus and/or fog
will develop late tonight with potentially IFR conditions
developing for a couple of hours at KFLO or KLBT.
Largely VFR conditions are expected after daybreak, however
daytime scattered showers and thunderstorms could bring short-
lived IFR conditions at any of our local airports mainly after
17z.
Extended Outlook...Slightly drier air may make it to the area
Tuesday into Wednesday with less coverage in convection and
better prospects for sustained VFR conditions.
&&
.MARINE...
Through Monday:
Surface high pressure off the NC coast will result in SW flow
persisting across the waters through Monday. Sustained speeds will
be on the order of 10 kt, with a few gusts to 15 kt, increasing a
bit Monday afternoon as the gradient tightens in response to a
Piedmont trough. A southerly 2 ft wind wave around 4 seconds will
mix with an easterly 2-3 ft/9-10 second easterly swell, which will
increase to 12-14 seconds across the waters north of Frying Pan
Shoals Monday afternoon.
Monday night through Friday ... Waves not large through the period
but a bit more `complex` than normal with 3 or 4 waves appearing in
spectral bulletins. Early on this is a NE swell of 13-14 sec as well
as the SSW wind wave. Veering winds slated Tuesday following FROPA.
Post-frontal NE winds to remain in place starting Wednesday as large
area of high pressure remains to our north, slowly progressing
eastward. Seas may build towards the end of the period as a long ENE
fetch becomes established around the anticyclone.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
Monday for NCZ107.
MARINE...None.
&&
$$
SYNOPSIS...ILM
UPDATE...TRA/CRM
NEAR TERM...CRM
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...TRA
MARINE...ILM
Area Forecast Discussion
National Weather Service Lincoln IL
924 PM CDT Sun Sep 11 2022
.SYNOPSIS...
Issued at 237 PM CDT Sun Sep 11 2022
A slow-moving weather system will keep conditions damp and cool
through Monday. The pattern then becomes drier and progressively
warmer from mid-to-late week.
&&
.UPDATE...
Issued at 920 PM CDT Sun Sep 11 2022
Steady clearing of the clouds will continue into our eastern CWA,
with low clouds mainly over areas along and east of I-57 as of 9
pm. The latest high resolution model updates are slowing down the
return of rain showers to our northern counties overnight.
Satellite and radar trends support an even slower arrival than
the models, therefore we have followed suit with our PoPs/Weather
grids for 06z-12z tonight. The southward push of the rain appears
to be more limited before sunrise as well. Rainfall amounts look
to remain only a few hundredths in any area that receives rain
through Monday morning, so QPF amounts were slashed as well.
Temps have already reached our forecast low at Galesburg (53),
but upstream dewpoints are not much lower upstream to the north,
and cloud cover will return prior to sunrise which will slow the
late night diurnal cooling. Have trimmed a degree or two in a few
spots across our NW. The spirit of the forecast remains for lows
in the low 50s. A stray upper 40 could occur near Altona.
The remainder of the forecast is on track. A breezy/blustery day
is on tap tomorrow.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 237 PM CDT Sun Sep 11 2022
Afternoon GOES-16 mid-level water vapor imagery depicts a closed
low positioned over the Quad Cities with the dry conveyor belt
spreading across central and eastern Illinois. With the drier
mid-level air mass in place, precip has lulled and low stratus
has begun to lift and break for some sun.
Despite some temporary clearing this evening, the cyclonic
extension of the warm conveyor belt will continue to flow north
and west into the comma head, resulting in a bit of a TROWAL over
northern and central Illinois overnight. Latest guidance from the
12z HREF reveals a good signal for banded precip Monday morning
along the I-74 corridor, with an additional round of light
rainfall possible later Monday afternoon. Latest QPF amounts from
WPC, which leans heavily on NBM and HREF guidance, suggests an
additional 0.25" along and north of I-74, with localized amounts
up to 0.50" through Monday afternoon. Further south, the vertical
profile will not be sufficiently saturated, and so a few
hundredths of rain is expected, at most. The main takeaway,
though, heading into Monday is continued cool and damp.
From a climatology focus, this mid-latitude cyclone is a bit
unusual. Not only is it an occluded, vertically-stacked system,
but its core is quite cold with RAP guidance offering -20 degC
over central Illinois tonight. That`s the coldest 500-mb temp we
have on record for 00z Sept 12, dating back to 1949. Despite the
very cold temperatures aloft, surface temperatures tonight will be
propped up by invading low-level stratus. Overnight lows will dip
into the lower 50s, only about 5-8 degrees cooler than what`s
considered normal for this time of year. The overall effect will
be more noticeable Monday afternoon as temperatures only warm into
the mid 60s, a good 15 degF cooler than normal.
.LONG TERM...(Monday night through Sunday)
ISSUED AT 237 PM CDT Sun Sep 11 2022
The upper-level low will begin to open and pivot eastward Monday
night as strong shortwave energy digs across Ontario. Skies will
clear behind the departing low and temperatures Monday night are
expected to bottom out in the upper 40s across southeast Iowa and
far west central Illinois. Further east where clouds may linger,
lows in the mid 50s may be more common.
Conditions turn drier and progressively hotter Tuesday through
Saturday as strong low-level warm air advection creeps into the
Mid-Mississippi Valley and mid-level heights increase. As the
ridge axis builds into the Midwest and Great Lakes region,
temperatures are expected to warm into the low-to-mid 80s
Wednesday and Thursday beneath full sunshine. Per NBM guidance,
upper 80s are possible Friday and Saturday.
The forecast becomes less clear by early next week as various
global models and their suite of ensemble solutions seem to
disagree on the timing and amplitude (position) of the next
upper-level disturbance as it moves onshore the Pacific Coast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 657 PM CDT Sun Sep 11 2022
MVFR conditions will continue to depart to the east this evening,
as a wave of dry air wraps into central Illinois south of the
surface low center. Spotty drizzle could occur while the MVFR
clouds persist for the eastern terminals for a couple hours.
Otherwise VFR conditions will prevail the rest of the evening.
High resolution models are pointing toward the next surge of rain
will rotate southward toward the I-74 terminals toward 06z
tonight. Ceilings may again fall into the MVFR range at
PIA/BMI/CMI just prior to 12z/7am Monday morning as the rain
lingers through mid morning across the north.
Northwest surface winds will diminish below 10KT sustained after
sunset. Winds will then briefly back to become westerly by
06z/1am.
Low-level wind shear has been continued at PIA/BMI/CMI between
07z-13z/2am-8am as winds around 2,200 ft AGL increase to 50+ kts.
W-NW winds will become gusty during the day Monday, with frequent gusts
to 25KT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SYNOPSIS...MJA
SHORT TERM...MJA
LONG TERM...MJA
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Indianapolis IN
946 PM EDT Sun Sep 11 2022
.Forecast Update...
Issued at 946 PM EDT Sun Sep 11 2022
Last of the showers associated with the cold front tracking through
Decatur County as of 0130Z and will be out of the forecast area
within the next hour. The rest of the forecast area is now within
the cold advection behind the front with lower stratus lingering
over much of the area along with a few small pockets of drizzle/
sprinkles. Feels like a touch of Autumn this evening with
temperatures in the 60s and a steady...cool northwest wind.
The overall forecast is in good shape for the rest of the night.
Expect a largely dry overnight as weak surface ridging builds in
behind the departing occluded front. The surface low however remains
back over the western Great Lakes and will wobble in tandem with the
trailing upper low before pivoting into northern Indiana on Monday.
Expect mainly cloudy skies for much of the forecast area
overnight...with some clearing across the southwest and Wabash
Valley before more clouds rotate in from the northwest prior to
daybreak with the upper low. Showers associated with the upper low
should hold off until after daybreak in the northern Wabash Valley.
Lows tonight will fall into the lower and middle 50s. Zone and grid
updates out.
&&
.Short Term...(This evening through Monday night)
Issued at 250 PM EDT Sun Sep 11 2022
Radar was showing widespread showers extending from northern
Illinois to southwestern Indiana early this afternoon. The activity
was associated deep moisture surging north in southerly flow and
synoptic lift courtesy of a cold front over east central Illinois
and intensifying upper low over Iowa. The cold front will sweep east
across central Indiana this afternoon and tonight as the associated
low occludes over southern Lake Michigan. Meanwhile, the upper low
will move across the Indiana and Michigan border Monday and to Lake
Erie Monday night. The convection will be diminishing and or ending
from southwest to northeast this evening. However, areas mainly
north of Interstate 70 could see more convection Monday and
especially Monday afternoon as a lobe of vorticity moves around the
southern base of the upper low.
PWATS 1.5-1.8 inches, lift, and instability will lead to a continued
threat for heavy rain the remainder of this afternoon and early
evening. 70 knot jet streak over the upper Wabash Valley will
encourage enhanced rainfall in RR quad over all but far northwestern
sections of central Indiana. Currently, there are only sporadic
lightning strikes despite MLCAPE 500-1000 J/kg and deep bulk shear
to 30 knots and with some breaks noted on visible satellite, would
not rule out an isolated strong or marginally severe thunderstorm
through sunset.
With the cold front sweep through and much cooler air behind it,
overnight lows will fall all the way to the lower 50s overnight.
This will be in spite of cyclonic flow and lobe of vorticity around
the upper low. Meanwhile, the clouds will hang around Monday,
especially over northern sections. This will limit afternoon
temperatures to the 60s there and lower 70s south.
&&
.Long Term...(Tuesday through Sunday)
Issued at 250 PM EDT Sun Sep 11 2022
* Cool to start with patchy morning fog possible at times
* Becoming drier with warming temperatures
Monday Night into Tuesday
Strong low pressure over southern Lake Michigan is expected to reach
peak intensity tonight and begin the occlusion process. As the
system sits and spins to our north, wrap-around flow should bring
much cooler air and a few light rain showers to central Indiana.
Largely cut off from the jet stream over southern Canada, the
occluded low will be slow to exit eastward. However, it will
gradually begin to make some progress by Tuesday morning. Much drier
air is wrapping around and into the circulation, and skies may start
clearing as early as Tuesday afternoon. Rather cool conditions are
likely through Tuesday, as 850 temps sit somewhere between 5 and 10
degrees C.
Wednesday through Sunday
Extensive surface high pressure should build into the Midwest after
today`s low departs. Clear skies with residual cold air aloft yields
lows in the 50s through Thursday, with perhaps a few locations
seeing upper 40s. Some patchy fog is possible Wednesday and Thursday
morning, especially with recent rain and rather cool lows expected.
Fog should be patchy in nature, given the rather dry airmass moving
in...and should be confined to fog-prone areas such as river valleys
and fields / basins. Any fog should burn off quickly after sunrise.
Ensemble guidance generally shows ridge building aloft through the
week, reaching its maximum around Thursday. Simultaneously, the
surface high pressure should gradually slide east allowing southerly
flow to return around the same time. Therefore, a warming trend is
expected this week. Both the ECMWF and GFS ensembles bring 850mb
temps to around 15 C by week`s end, translating to surface
temperatures in the middle to upper 80s by Friday. By the weekend, a
possible break in the warming trend is possible as deterministic
models show a few shortwaves ejecting from the Rockies along with a
flattening ridge. However, details at this range are subject to
great uncertainty...so only kept slight PoPs to account for this
possibility along with slightly cooler temps on Sunday. Overall,
expect a return to warmer than average and drier conditions for the
upcoming week.
&&
.Aviation...(00Z TAF Issuance)
Issued at 722 PM EDT Sun Sep 11 2022
Impacts:
- Predominately MVFR conditions overnight near KLAF & KIND
- MVFR conditions improve to VFR later tonight near KHUF & KBMG
Discussion:
Isolated showers will be possible over the next few hours, but are
expected to diminish by 02z with the cold front exiting central
Indiana. Would not rule out some lingering patchy showers overnight
and also by Monday morning near KLAF with the upper low still in
close proximity. MVFR conditions should prevail near KLAF & KIND
through the night with improving conditions overnight across the
other TAF sites. Brief VFR conditions are possible near KIND at
times overnight.
Winds will be west and northwest around 5-10 knots overnight, but
then switch back to southwest tomorrow morning as the upper low
intensifies. Wind gusts up to 25kts will be possible tomorrow.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Update...Ryan
Short Term...MK
Long Term...Eckhoff
Aviation...Melo
Area Forecast Discussion
National Weather Service Northern Indiana
804 PM EDT Sun Sep 11 2022
.SYNOPSIS...
Issued at 745 PM EDT Sun Sep 11 2022
Showers and isolated thunderstorms will taper from west to east this
evening as a cold front tracks across the area. A few isolated
showers could linger overnight. Otherwise, additional rain is
expected on Monday as much cooler air filters into the region.
High temperatures on Monday will only reach into the low to mid
60s, but temperatures will moderate back into the upper 70s by
Wednesday. A beach hazards statement is in effect for dangerous
conditions on Lake Michigan tonight into Monday morning.
&&
.UPDATE...
Issued at 745 PM EDT Sun Sep 11 2022
Had to do a quick update for primarily the marine zones, but also
somewhat inland for the wind bump/adjust pops slightly. Gusts off
Lake Michigan (mid and nearshore) are already up to around 25-30
knots and waves rapidly increased ahead of the system responsible
for todays rain and isolated storms. We had waterspouts observed
near St Joseph this afternoon, so added those into the forecast
through this evening. Gale force gusts up to 35 to 40 knots are
expected through late tonight (already observed at several
points), so issued a shorter duration gale warning that goes
through 6z, and a small craft advisory to follow it up.
Waves at Michigan city behind the wind speed max built up to
around 3-5 feet, and shortly behind it south haven/st joseph
showing waves picking up into the 3-5 ft range. Despite the later
timing, opted to issue a beach hazards statement given the
dramatic increase to the wind/wave forecast-people could be caught
off guard on the piers and get washed off into the water. Wave
periods of 5 to 7 seconds were also observed, in addition to
intersecting wave trains from separate sources (one from the N-NW,
new wind waves from wind speed max from the west-southwest). This
has been known to increase the risk of dangerous current
development, so have the statement continuing until 15z Monday to
cover any residual currents/subsiding waves in the morning. We
also have a decent pressure rise/fall couplet and cold front
crossing the Lake, so that increases our potential for water level
fluctuations (seiches, meteotsunamis)-which lends more confidence
to the threat for dangerous currents.
&&
.SHORT TERM...(This Evening through Monday)
Issued at 426 PM EDT Sun Sep 11 2022
Showers will taper from west to east this evening, and the main
weather story going forward will be the transition to much cooler
temperatures later tonight and Monday.
Potent upper vort lobe rotating around parent upper level low
will continue to eject northeast across the southern Great Lakes
this evening. Extensive clouds and precipitation have limited
instability this afternoon, with latest RUC analyses indicating
500-1000 J/kg of MLCAPE. Factors favorable for locally heavy
rainfall are still in place this afternoon including warm cloud
depths in excess of 10k feet and anomalous pre-frontal PWATs of
1.6-1.75 inches. However, it still appears as though progressive
nature of frontal forcing should preclude any widespread hydro
issues with lessening potential of training through the remainder
of the afternoon. Some better mixing has developed this afternoon
across northwest Ohio with sfc temperatures reaching into the mid
and upper 70s across the far east/southeast. A few cells could
produce sub-severe wind gusts to 30+ mph across northwest Ohio in
narrow window through late afternoon.
Mainly dry weather overspreads the area this evening as mid level
dry slot pushes across the area. A few showers may linger into late
evening/early overnight across the far north/northeast where deeper
moisture profiles reside the longest. Mid level moisture wrapping
around this occluding system with TROWAL-like feature should
reintroduce a better chance of showers across west-southwest
portions of the forecast area toward morning. Mid level cold core on
Monday could be enough for perhaps an isolated thunderstorm with
very weak elevated instability, but this potential appears to be
too low to mention in forecast grids. Scattered showers should
gradually expand eastward across far NE Indiana/NW Ohio later in
the day Sunday.
Much cooler weather in store for Monday (highs only reaching into
the low to mid 60s) with breezy conditions as low pressure slowly
begins to fill across southern Lake Michigan Monday morning. With
extensive low cloud coverage likely on Monday and much cooler low
level temps, highs should be limited to the lower to middle 60s
across the area.
&&
.LONG TERM...(Monday Night through Sunday)
Issued at 426 PM EDT Sun Sep 11 2022
Precip potential will wind down Monday night into Tuesday as upper
low begins to drift across the eastern Great Lakes. Lingering
effects from TROWAL/deformation forcing should prolong some
isolated/scattered showers across NW Indiana/SW Lower Michigan
into Monday night/early Tuesday with some possible enhancement to
low level deformation forcing from Lake Michigan weak aggregate
trough development. Still expecting clouds to scatter later in the
day Tuesday, but confidence still somewhat on the low side
regarding timing.
Otherwise, a quiet period setting up for the remainder of the
forecast period with upper level ridging building across the region
and onset of low level warm advection on Wednesday. There are
continued indications in medium range guidance of a short wave
dampening this ridge across Upper Midwest next weekend, but a large
spread still exists in timing/strength of this wave. High confidence
remains in moderating temperatures back to normal/above normal
temperatures late in the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 745 PM EDT Sun Sep 11 2022
MVFR to IFR conditions are expected at the TAF sites, with
occasional bumps to VFR. The initial precipitation batch ahead of
our low pressure system has moved off from both terminals, with
our area in the dry slot. During this time could remain primarily
VFR/high-end MVFR before we see the second push behind the cold
front. Some of the models are still suggesting that light
drizzle/isolated shower and BR potential (lingering LL moisture),
particularly at KFWA so with more confidence added the predominant
group for IFR conditions between 9-14z. Kept KSBN predominantly
MVFR for now, but wouldn`t be surprised to see a couple dips into
the IFR category if we get a heavier shower or some of that
drizzle. Additional showers are expected through Monday,
especially after 18-21z.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Beach Hazards Statement through Monday morning for INZ003.
MI...Beach Hazards Statement through Monday morning for MIZ077.
OH...NONE.
LM...Gale Warning until 2 AM EDT Monday for LMZ043-046.
Small Craft Advisory from 2 AM to 11 AM EDT Monday for LMZ043-
046.
&&
$$
UPDATE...MCD
SYNOPSIS...MCD
SHORT TERM...Marsili
LONG TERM...Marsili
AVIATION...MCD
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Area Forecast Discussion
National Weather Service Marquette MI
1154 PM EDT Sun Sep 11 2022
.SHORT TERM...(Through this evening)
Issued at 119 PM EDT SUN SEP 11 2022
RAP analysis and GOES 16 water vapor imagery highlights broad
troughing extending south out of Hudson Bay into the Central Plains.
The open wave that was responsible for rain the past two days has
cut off at 500mb over Iowa. Upper level dynamics have supported a
surface low developing near Chicago along the slow moving surface
boundary. The cloud shield from these features extended north across
the forecast area this morning, but we`re starting to see some
clearing as things mix out. Highs so far have only reached the low
to mid 60s. Rain has more or less remained in the vicinity of the
surface low to our south, save for diminishing activity this morning
near Lake Michigan. As we progress through the remainder of today,
northerly flow will persist as the surface low to our south
continues to develop and inch its way north toward Milwaukee. Some
light rain can`t be ruled out across parts of Menominee County as we
go into the evening hours.
.LONG TERM...(Tonight through Sunday)
Issued at 350 PM EDT SUN SEP 11 2022
The low S of the forecast area - that is the primary focus to
start off this forecast period, with the question lingering of how
far N and W the precip shield will get. Model guidance has come
into somewhat decent, reasonable agreement that the precip won`t
extend beyond a line stretching from around the city of Marquette
to near Crystal Falls. Additionally, while some clouds will extend
well beyond that, spilling into portions of the Wrn U.P., there
appear to be enough breaks in said cloud coverage to allow for
temps to drop off a bit, and have therefore accounted for all of
this in this afternoon`s forecast update. In other words, expect
gradients for both the precip and temps tonight, dry and cool in
the W, not-so-dry and warmer in the E, the former temps-wise due
to radiational cooling while the latter temps-wise will be due to
moderation. Rumbles of thunder can`t be ruled out, but appears to
be a low probability at this time due to a lack of instability.
Once the well-advertised closed low finally treks across the lower
portions of the Great Lakes region and into Srn Ontario by
Tuesday, dry conditions will prevail everywhere across the U.P. as
ridging builds in. The ridge`s impact will be felt through mid-
week until the next disturbance rides along its periphery and
ejects out of the Plains to round out the latter half of this
week. Expect precip to return then, with again somewhat reasonable
agreement amongst the longer-range deterministic models of more
widespread PoPs then.
Although temps will bounce around a bit this week, expect
generally seasonable highs and lows for mid-September. The two
cooler days will be tomorrow and Wednesday, with highs in the 60s
and 70s otherwise. Lows will be a little more chaotic, with
clouds, precip, radiational cooling, etc. all influencing just how
low they go (or conversely, how warm they stay).
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1153 PM EDT SUN SEP 11 2022
IMPACTS:
- IFR/LIFR fog at IWD through daybreak Monday
- MVFR fog/CIGS at KSAW in the Mon 12-18Z time frame
- Wind gusts up to 20 kts at KSAW mid-morning Monday
Discussion:
Rain showers will linger at KSAW through daybreak Monday as a low
pressure system rotates over southern Lake Michigan. Expect VFR
conditions at KSAW through daybreak then deteriorationg to MVFR
CIGS/fog from Mon 12-18Z. Elsewhere, fog is going to be a threat
at KIWD where skies are clear. IFR fog is expected to prevail
early this morning at KIWD with possible LIFR closer to daybreak.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 410 PM EDT SUN SEP 11 2022
Wind gusts in the Ern portions of Lake Superior will approach 20
to perhaps 25 knots from out of the N to NE tonight into tomorrow.
Winds then slacken tomorrow night to less than 20 knots through at
least early Tuesday. However, by late Tuesday, N to NErly winds
will pick back up, gusting to 20 to 25 knots. The winds will then
remain elevated through much of the remainder of the week, peaking
at around 30 knots from out of the E to SE later Thursday through
week`s end.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JTP
LONG TERM...lg
AVIATION...TDUD
MARINE...lg
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 310 PM CDT Sun Sep 11 2022
Forecast Summary:
- Warming temperatures this week, peaking on Wednesday.
- Strong southerly winds Wednesday.
- Several low end chances for precipitation to end the week.
Today through Wednesday:
Temperatures have outperformed today with many locations reaching
our forecasted high temperature by 1 PM. I expect some locations
to reach at least 80, which is near the climatic average high
temperature this time of year. Also of note, is the big drop of
the dewpoint temperatures this afternoon. Dewpoint temperatures
are 10 to 15 degrees lower than yesterday due to drier northwest
flow and mixing of drier air aloft.
The weather is expected to be uneventful for the next several
days due to a high pressure system dominating the area. The main
forecast challenge will be temperatures, which are forecast to
increase through Wednesday as a mid-level ridge moves over the
area. The high temperature forecast for Omaha through Wednesday is
81, 86, and 90. It wouldn`t be surprising to see temps outperform
those numbers by a a couple of degrees. Warm air advection at the
lowest levels can be expected initially due to westerly winds and
downslope flow. On Tuesday, the winds will become southerly and
increase in strength and continue through Wednesday. These are
situations where we typically under forecast temperatures. In
review of today`s forecast, the NBM 90th percentile was the most
accurate temperature forecast. For Omaha, the NBM 90th percentile
through Wednesday is 84, 90, and 92.
Outside of temperatures, winds will be light until Wednesday.
On Wednesday, peak surface winds from the south will be between
20 to 25 mph with gusts up to 35 mph. Due to the aforementioned
high pressure, skies will remain mostly clear outside of afternoon
cumulus fields. Additionally, their may be a slight haze in the
sky beginning on Tuesday as the RAP smoke model suggests that
smoke from the western wildfires will be transported over the
area.
Thursday through Saturday:
Medium range guidance is in good agreement in bringing some weak
disturbances over the central CONUS beginning on Thursday. This
will put the area in an active southwest pattern that will lead to
several chance (25-55%) precipitation opportunities in this
period. These weak disturbances will likely lead to high
temperatures in the low 80s. Low temperatures will be in the high
50s/low 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 555 PM CDT Sun Sep 11 2022
VFR conditions will prevail through the forecast period with light
winds.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Fajman
AVIATION...Mead
Area Forecast Discussion
National Weather Service Reno NV
143 PM PDT Sun Sep 11 2022
.SYNOPSIS...
Smoke and haze from the Mosquito Fire will continue to affect air
quality across the Tahoe Basin, Martis and Carson Valleys as well
as the Truckee Meadows. Showers and thunderstorms remain possible
today and become more likely for Monday. Temperatures will remain
5-10 degrees above averages today with a cooling and drying trend
and typical afternoon breezes most of the week.
&&
.SHORT TERM...
Poor air quality across the region persists from the Mosquito Fire,
bringing smoke and haze. Many air quality sensors in the Tahoe Basin
are reporting unhealthy to hazardous air quality, and this is
expected to remain the story through today. Recent HRRR Near Surface
Smoke models indicate a dense plume of smoke returning to the Reno-
Carson area this afternoon, where it will hang through the overnight
hours. There is no good way to say this, but being outdoors is not
going to be good for anyone for today and tonight. You can monitor
your air quality in your neighborhood at fire.airnow.gov.
This smoke may inhibit development of afternoon heating and
instability, which may limit storm activity this afternoon to a more
showery regime. Showers and storms will initialize today along the
Sierra, but may reside along and west of the crest. PWAT values
range 0.75-1.00" across the region, signaling that showers may be
efficient in rain production causing localized flooding concerns
under heavy showers. Storms that form may contain frequent
lightning and gusty outflow winds up to 45 mph. The outflows may
become a concern for blowing dust in dry sinks and lake beds.
Another concern for outflow winds will be area lakes becoming
choppy as breezes kick up.
For Monday, showers and storms return as a low pressure circulation
centered over the Pacific Northwest sends a trough into the picture.
This looks to enhance storm production as the trough provides a
shear component that will allow storms to become more organized than
today`s round of precipitation. Precipitation chances for the Sierra
will be 60-80%, while Tahoe Basin and Reno-Carson will have around a
50% chance of seeing showers and storms for Monday.
Temperatures on Monday will stick just above or around averages
for September. The thicker smoke layers will also keep daytime
heating in check for some areas. This could result in slow
insolation rates that prevent the temperatures from climbing for
areas stuck under dense smoke. Monday night some Sierra
communities such as Martis Valley may see freezing temperatures,
signaling an oncoming transition into fall weather patterns.
-HRICH
.LONG TERM...Tuesday through Sunday.
Cooler weather is expected for the bulk of next week as a trough
develops over the northwestern U.S. High temperatures will be near
or even a little below seasonal averages with low 80s in western
Nevada and low 70s in Sierra valleys through the week and into next
weekend. Thunderstorm activity will be subsiding as drier southwest
flow moves into the region, but there will still be a slight chance
for storms in Mono/Mineral counties on Tuesday with lessening
chances on Wednesday.
A stronger trough is forecast to develop in the eastern Pacific
around next weekend. Current projections keep precipitation confined
mainly to the coast, but the incoming trough could bring a day of
increased wind to the Sierra and western Nevada next weekend. This
will also continue to keep temperatures near or below average for
the following week. -Zach
&&
.AVIATION...
Ongoing fires are producing smoky and hazy skies across the
region. Visibilities will be reduced in TRK, TVL, RNO, CXP and MEV
through today into tomorrow. Conditions will oscillate between
MVFR/IFR as the smoke plume from the Mosquito Fire lofts over
western Nevada and northern Sierra in California. Concerns include
reductions in slantwise visibility and mountain obscuration during
periods of dense smoke.
This afternoon, chances for showers and storms exist for all
terminals. Monday`s chances are higher, with a possibility for
storms to become more organized.
Winds will generally be light until this afternoon when storms could
produce gusty outflows up to 45 mph. Monday`s stormy outlook
increases chances for outflows to be present where convection
forms and collapses. -HRICH
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
Area Forecast Discussion
National Weather Service Las Vegas NV
727 PM PDT Sun Sep 11 2022
.SYNOPSIS...Isolated to scattered thunderstorms will persist
through this evening, and then the heavy rain threat will likely
ramp up tonight through Tuesday as the remnant circulation of Kay
moves inland. Southwest flow should finally bring a drying trend
late in the week.
&&
.UPDATE...Widely scattered thunderstorms tried to develop across the
region today, however they struggled as moisture has decreased since
yesterday and no notable forcing mechanisms were in place to help
storms along. Most of the thunderstorm impacts today were in San
BErnardino County where some residual moisture was in place and
storms trained along the terrain near Twentynine Palms. In the past
few hours, convection overall has decreased, though ongoing isolated
storms persisted in portions of Mohave County as well as northern
San Bernardino County. Mesoanalysis and short-term model trends
would support a continued downward trend and this round of
convection ending in the next couple of hours.
Eyes then turn to the overnight period where another round of
precipitation is expected to develop and push north tonight, likely
after 06Z. Overall, not much change in the expectations overnight. A
moisture surge will push north through Mohave County and the
Colorado River Valley which will act as a pseudo warm front, not
only ushering in higher PWATs and dewpoints but providing a trigger
for precipitation to blossom. Precipitation should overspread
southern Mohave County and the Colorado River Valley through the
night, with showers and storms making into southern Clark County by
Monday morning. While these storms should have decent storm
movement, latest HRRR runs suggest widespread precipitation that
could be heavy at times and potentially move over the same areas more
than once. Most impactful time period overnight will be 09Z through
15Z, which short term models are highlighting for rapidly developing
precipitation and the highest rainfall rates- especially in the
southern half of Mohave County. Impacts to the morning commute are
likely in mohave County into southern Clark County from overnight
rainfall. Flash flooding will be possible where heavy rain falls and
multiple rounds of rain are possible, with the highest risk in
Mohave County south of the Arizona Strip.
--Nickerson--
&&
.PREVIOUS DISCUSSION...255 PM PDT Sun Sep 11 2022
.SHORT TERM...through Monday night. Early afternoon satellite loop
showed thunderstorms beginning to develop over San Bernardino and
Inyo counties, with shallower cumulus elsewhere. Surface obs showed
temperatures running several degrees warmer than yesterday at most
stations thanks to the reduced cloud cover, and dewpoints several
degrees lower than yesterday. As anticipated, this morning`s
sounding showed lower precipitable water than yesterday, so the
flash flood threat is reduced (but not zero) today. The remnant mid
level circulation of Kay was near 30N 120W at noon, and will track
slowly northeast across the Desert Southwest Monday and Monday
night. Isolated thunderstorms will persist through this evening, and
then active weather starts to crank up tonight. A vort lobe and
moisture push ahead of the remnant circulation will cause
thunderstorms to break out overnight in the lower Colorado River
Valley and track north to Clark County by morning. These will likely
be moving too quickly to cause significant hydro problems. In the
afternoon, the plentiful moisture will combine with some sun,
differential heating boundaries left over from the morning storms,
and orographics to fuel scattered thunderstorms. Again, spotty heavy
rain may occur, but there doesn`t appear to be a widespread risk of
flooding. Storms should settle down somewhat after sunset.
.LONG TERM...Tuesday through Saturday.
Very active period likely to stretch into Tuesday as remains of Kay
and additional jet dynamics come into play over the area. Heavy rain
remains the primary concern, and a Flood Watch has been issued for
Esmeralda, Nye, and Lincoln counties Tuesday and Tuesday night. Some
storm chances will continue Wednesday into Thursday as a drier
southwest flow gradually scours moisture out of eastern Nevada by
Friday and Saturday. As we transition into that drier southwest flow
look for stronger afternoon breezes and temperatures returning back
to seasonal normals by the weekend.
&&
.AVIATION...For Harry Reid...Light east-southeasterly winds will
continue for the next few hours before shifting to the southwest
around sunset. Around 11/12Z Monday, winds are expected to shift to
the southeast with 15-20 knot gusts likely. Additionally, showers
and thunderstorms will begin to move into the vicinity of the
airport around this time. These showers will likely move into the
terminal area between 12Z and 16Z. As showers move over the terminal
area and the Las Vegas Valley early tomorrow morning, they will
likely be accompanied by variable gusty winds.
For the rest of southern Nevada, northwest Arizona and southeast
California...KVGT and KHND are expected to follow similar trends to
KLAS, with east-southeasterly winds through the afternoon becoming
more diurnal overnight. Showers and thunderstorms will begin to move
into the Las Vegas Valley around 11/12Z with winds picking up and
swinging to the southeast at that time. The most likely time for
precipitation to impact the terminal areas is between 12Z and 16Z.
KBIH will continue to favor a more southerly direction with 15-20
knot gusts possible through the evening before becoming light and
variable early tomorrow morning. Breezy easterly winds with 20-25
knot gusts will continue into the evening hours at KDAG. After
sunset winds will shift back to the west with gusts dropping off.
Vicinity thunderstorms will be possible this afternoon but are
expected to dissipate by sunset. Winds at the Colorado River Valley
sites will tend to favor a more southerly direction with showers and
thunderstorms moving into the vicinity and potentially over the
terminal areas beginning around 09Z. Variable gusty winds will
likely impact the terminal areas as these showers and thunderstorms
move through. By 15Z showers and thunderstorms should have cleared
the Colorado River Valley with winds becoming light and variable.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
SHORT TERM...Morgan
LONG TERM...Pierce
AVIATION...Stessman
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