Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/16/24
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
601 PM MDT Sun Sep 15 2024
...New AVIATION...
.SYNOPSIS...
Issued at 123 PM MDT Sun Sep 15 2024
Greater coverage of showers and thunderstorms will continue over the
region through Tuesday. This activity will be capable of producing
locally heavy rainfall, strong winds, hail, and frequent lightning.
A few storms over the region may become strong to severe, especially
over northwest NM on Monday then over parts of eastern NM Tuesday.
Drier and breezy weather will return Wednesday and Thursday with
warming temperatures once again. A couple storms are still possible
over far eastern NM however chances are still low. The next storm
system may approach Friday with cooler temperatures, more wind,
and storms possibly over eastern NM. The coolest temperatures so
far this season may arrive behind this system for next weekend.
&&
.SHORT TERM...
(This evening through Monday)
Issued at 123 PM MDT Sun Sep 15 2024
Looking at IR and WV satellite imagery, there is no evidence to
former tropical storm Ileanas whereabouts, but total precipitable
water products from the GOES imagers do indicate PWATs nearing 1.5
to 2.0 inches over southern Sonora in Mexico. Surface dewpoints and
PWATs are already climbing slowly in NM and this will continue into
Monday, but on a very modified basis (ensembles showing a crest near
0.8 inch near ABQ late Mon with other areas closer to 1.0 inch). The
upper low has dropped over the WA/OR coastline and should be
overtaking the northern CA coast through the late afternoon. This
will continue to draw the subtropical segment of the jet into NM
tonight and Monday before the polar segment noses its way toward the
Four Corners Monday night. This speed max will introduce some
divergence and forcing aloft, allowing broken lines of showers and
storms to redevelop over western and central NM with some periodic
isolated cells roaming into east central and northeastern sections
of the forecast area through early this evening. Overnight, high
resolution CAMs and global models have a consensus for rain focusing
over northwestern to west central NM as a jet streak aloft
approaches.
On Monday, the low will work into the Great Basin of Nevada with
strong jet dynamics evolving, but still feeding upward forcing into
much of western and northern NM. Healthy speed shear would be
present areawide with northwestern areas being the most likely to
observe strong to severe cells, mainly from downburst winds, but
also a hail threat Monday afternoon and evening. The stronger
southwesterlies aloft and gradually strengthening surface gradient
will also produce stronger prevailing breezes Monday, and lower
pressure heights and increased clouds will cool temperatures just a
couple of degrees. Showers and storms would persist well into the
overnight hours as the low chugs toward the northeast corner of NV,
and precipitation should inch eastward some as forcing aloft does
the same. While storm motions will be fast-paced, there is a threat
of multiple rounds of storms on the Hermits Peak-Calf Canyon
wildfire burn scar, so a Flood Watch will be hoisted for Monday.
&&
.LONG TERM...
(Monday night through next Saturday)
Issued at 123 PM MDT Sun Sep 15 2024
A 559dm H5 low positioned over northeast NV Tuesday morning will
move E/NE into western WY thru the afternoon. A potent H3 jet axis
near 110kt over northwest AZ in the base of this wave will slide
east while weakening to near 85kt over northwest NM Tuesday. A
secondary speed max near 65 kt draped across southern AZ Tuesday
morning will be absorbed into the stronger speed max farther north
thru the day. This subtle feature may have implications on forcing
convection from Monday night to continue over central and western
NM thru Tuesday morning. The southern speed max coincides with a
mid level dry intrusion approaching from the west, which will also
assist the overall large scale ascent increasing over the region.
Rich moisture in place over NM will be wrung out in the form of
numerous showers and storms from the central mt chain eastward
into Tuesday evening. The 13Z NBM shows the greatest probs for
>0.25" rainfall over the northern mts and the northeast plains.
Another Flash Flood Watch may be needed for the HPCC burn scar.
Some of this activity may be strong to severe over eastern NM with
bulk shear values increasing to between 40 and 50kt, boundary
layer CAPE of 500-1000 J/kg, and PWATs from 0.75" to 1.25". Model
guidance continues trending farther west with the stronger storm
initiation Tuesday morning. The latest HRRR even shows activity
ongoing before sunrise along the central mt chain. The latest SPC
severe weather outlook shows only northeast NM under a `Marginal
Risk` for severe storms however this may warrant expansion to all
of eastern NM if these trends continue. Storms will likely end by
midnight across eastern NM while drier and cooler air filters in
from the west.
Wednesday and Thursday will feature strengthening southwest flow
aloft ahead of the next strong H5 low entering the Great Basin. Much
drier air with breezy southwest winds will spread over much of NM
along with warmer temps. Near-record highs are possible again around
Roswell with temps in the upper 90s both days. A couple storms are
possible over the far southeast plains where some guidance hangs
onto deeper low level moisture and instability, however confidence
is low.
Extended models are still advertising the H5 low moving east over
northern NM Friday and Saturday. Cooler air will arrive with this
system along with more wind and increasing chances for showers and
storms across the north and east.
&&
.AVIATION...
(00Z TAFS)
Issued at 534 PM MDT Sun Sep 15 2024
Isolated to scattered showers and thunderstorms producing
lightning, and brief heavy rain continue to trend down this
evening. Lcl wind gusts to 40 kt remain possible this evening
from any passing showers or storms. Isolated showers and storms
shift to northern and eastern NM after midnight. On Monday,
showers and storms will be most likely over the northwest third
to half of the state with prevailing southwest winds on the
increase during the afternoon.
&&
.FIRE WEATHER...
Issued at 123 PM MDT Sun Sep 15 2024
The weather pattern is changing today as moisture seeps into the
area from the southwest and a deep low pressure system moves down
the west coast. This setup will continue to lead to the development
of more showers and thunderstorms over western and central NM today,
focusing more over western areas tonight. A few sparse or isolated
storms may even impact northeastern to east central NM through early
this evening. Wetting rainfall will still be somewhat hit-and-miss
through tonight, however on Monday, the previously mentioned low
pressure system will move into the Great Basin of Nevada, spreading
any remnant tropical moisture over western and northern NM. This
will keep scattered to numerous showers and thunderstorms
redeveloping over most western and northern zones Monday. Prevailing
breezes will be gusty, occasionally hitting 20 to 30 mph Monday
afternoon, but even gustier winds will accompany passing showers and
storms, especially in northwestern NM. In addition, brief heavy
downpours and possible wildfire burn scar flooding (mainly over the
Hermits Peak-Calf Canyon scar) will be of concern Monday while
humidity rises and peaks. Scattered to numerous showers and
thunderstorms will still be common Tuesday morning, but drier air
will arrive later in the day, pushing storms to the eastern half of
NM. The prevailing winds will strengthen a bit more Tuesday,
especially in the far northeastern corner of NM where gusts may even
occasionally reach 35 to 45 mph, and local storms would be capable
of enhancing these winds for brief periods. Moisture exits NM on
Wednesday, eliminating rain chances for the day and possibly even
through Thursday, but low level moisture will return on Friday,
leading to scattered strong dryline storms. This moisture could
linger in eastern NM until Saturday, pending the outcome of a
potential cold front. Elsewhere, a mostly dry and breezy forecast
will hold.
&&
.PRELIMINARY POINT TEMPS/POPS...
Farmington...................... 59 79 57 74 / 60 80 50 50
Dulce........................... 47 72 47 68 / 50 80 70 80
Cuba............................ 51 76 51 72 / 50 80 50 70
Gallup.......................... 52 78 50 73 / 50 70 30 30
El Morro........................ 50 75 49 71 / 60 70 30 40
Grants.......................... 50 79 49 77 / 50 70 30 50
Quemado......................... 51 77 50 75 / 50 50 30 30
Magdalena....................... 56 79 56 79 / 30 50 30 40
Datil........................... 50 76 48 75 / 30 60 30 30
Reserve......................... 51 80 51 76 / 40 50 30 30
Glenwood........................ 58 82 58 79 / 30 50 40 20
Chama........................... 45 66 46 62 / 40 80 70 80
Los Alamos...................... 55 76 55 74 / 40 70 60 80
Pecos........................... 51 77 52 70 / 40 60 60 70
Cerro/Questa.................... 48 72 49 68 / 20 70 50 60
Red River....................... 39 65 42 60 / 20 70 50 70
Angel Fire...................... 38 67 43 64 / 30 70 40 70
Taos............................ 47 77 49 72 / 20 60 40 60
Mora............................ 46 74 48 69 / 30 70 50 80
Espanola........................ 55 84 56 81 / 40 60 60 70
Santa Fe........................ 55 78 57 73 / 40 60 60 70
Santa Fe Airport................ 56 83 55 78 / 40 60 50 60
Albuquerque Foothills........... 57 83 60 82 / 40 50 50 50
Albuquerque Heights............. 60 85 62 83 / 40 50 40 50
Albuquerque Valley.............. 55 87 57 85 / 40 50 40 40
Albuquerque West Mesa........... 58 85 61 83 / 40 50 40 40
Belen........................... 57 88 58 86 / 30 40 40 30
Bernalillo...................... 57 86 59 85 / 40 50 50 50
Bosque Farms.................... 55 87 56 85 / 40 50 40 30
Corrales........................ 57 86 59 85 / 40 50 50 50
Los Lunas....................... 56 87 57 85 / 40 40 40 30
Placitas........................ 56 83 58 81 / 40 60 50 60
Rio Rancho...................... 59 85 61 84 / 40 50 50 50
Socorro......................... 61 88 62 88 / 30 30 30 20
Sandia Park/Cedar Crest......... 54 79 54 75 / 40 60 50 60
Tijeras......................... 55 81 56 78 / 40 60 50 60
Edgewood........................ 53 81 53 78 / 40 50 50 60
Moriarty/Estancia............... 49 82 50 80 / 40 50 50 60
Clines Corners.................. 51 79 53 75 / 40 50 50 60
Mountainair..................... 53 82 54 78 / 30 40 40 50
Gran Quivira.................... 53 82 55 78 / 30 40 40 40
Carrizozo....................... 58 84 60 81 / 20 30 30 40
Ruidoso......................... 48 77 50 75 / 20 30 30 60
Capulin......................... 51 78 52 73 / 20 30 20 50
Raton........................... 50 81 53 76 / 20 40 20 60
Springer........................ 51 83 54 78 / 20 40 30 60
Las Vegas....................... 50 79 52 74 / 30 50 40 70
Clayton......................... 59 86 60 83 / 20 10 20 40
Roy............................. 56 82 57 77 / 20 30 40 60
Conchas......................... 60 90 61 85 / 20 20 40 60
Santa Rosa...................... 59 85 60 82 / 30 20 40 60
Tucumcari....................... 60 90 62 88 / 20 10 20 60
Clovis.......................... 62 90 62 89 / 5 5 10 40
Portales........................ 61 90 63 90 / 5 5 10 30
Fort Sumner..................... 60 88 62 88 / 10 10 20 50
Roswell......................... 65 92 67 92 / 0 10 10 30
Picacho......................... 58 84 60 86 / 10 20 20 40
Elk............................. 54 82 57 84 / 10 30 20 40
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Flood Watch from Monday afternoon through late Monday night for
NMZ214-215.
&&
$$
SHORT TERM...52
LONG TERM....42
AVIATION...33
Area Forecast Discussion
National Weather Service Cheyenne WY
946 PM MDT Sun Sep 15 2024
.KEY MESSAGES...
- Scattered thunderstorms may develop late this afternoon and
evening along and east of I-25. Isolated storms will have the
potential to become strong to severe.
- Chances for showers and thunderstorms continue through
Tuesday, followed by another chance for precipitation and
cooler temperatures late in the week.
&&
.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 320 PM MDT Sun Sep 15 2024
A shortwave pushing into the CWA this afternoon will be responsible
for the development of showers and thunderstorms later this
afternoon and into the overnight hours. Hi-Res guidance is in good
agreement with storms developing off the Laramie Range and gradually
pushing east into Nebraska by this evening. Radar still remains
fairly quiet, with just a few showers over the high terrain in
Colorado. Models also show considerable amounts of low-level CIN for
storms to overcome this afternoon, hence the likely later convective
initiation time. However, as previously mentioned, Hi-Res guidance
seems confident in storm development despite the CIN. Model
soundings do show relatively impressive CAPE values for this time of
year, ranging from 1000 to 1500 J/kg. This along with synoptic scale
lift from the incoming trough should be enough to get scattered
storms. Cannot rule out a strong to marginally severe storm today
given the environment. The HRRR does show perhaps one or two more
organized cells early this evening lending itself to a hail threat,
before becoming a more disorganized cluster of storms with more of a
strong wind threat. As mentioned, storms will continue into the
overnight hours, but should clear out by early Monday morning.
Looking at likely a drier day on Monday as strong southerly flow
ahead of the upper-level trough to the west continues to advect warm
air into the region. Still expect mild, above average temperatures
across much of the area. Cannot rule out a few isolated showers west
of the Laramie Range as the southerly flow may also advect some
moisture into this area. However, models have backed off from
previous runs regarding how much moisture to push into our CWA.
Currently, the most favorable area for moisture looks like
southwest Colorado. Whatever moisture does make it into the CWA
could be enough to spark a few showers during the afternoon, but
even Hi-Res guidance is not very excited about the possibility
of much precipitation.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 345 AM MDT Sun Sep 15 2024
Primary forecast concerns in the long range will primarily
relate to the longwave pattern change expected by mid to late
week, and the potential for some moderate to locally heavy
rainfall amounts (snow accumulations in the higher mountains)
next weekend as the Rex Block over the eastern United States
results in very slow movement of Pacific storm systems moving
east across the Front Range. It looks like the warm late summer
temperatures will come to an end on Thursday, with a more fall-
like pattern setting up across the region after September 20th.
Early this week, the Front Range will still be under the
influence of southwest to southerly flow aloft with 700mb
temperatures near 12c Tuesday. This translates to high
temperatures in the 80s to near 90 for the high plains and low
to mid 70s west of the Laramie Range. Models show the first of a
series of Pacific upper level troughs moving eastward across
the Great Basin Region on Monday and across Wyoming on Tuesday.
Most of southeast Wyoming and western Nebraska will be in the
region of diffluent flow aloft ahead of the trough axis. With
some low level instability, afternoon showers and thunderstorms
are expected...especially once the trough axis lifts northeast
and a surface cold front begins to move into central and eastern
Wyoming. Not expecting severe weather at this time due to
limited moisture, but a few strong storms are possible due to low
level and midlevel forcing, decent 0-6 km shear, and moisture
advection through the afternoon hours. Surface cold front will
push through the area and into western Nebraska by Tuesday
night, with daytime temperatures closer to normal for this time
of the year Wednesday. Windy conditions are expected Tuesday and
Tuesday night with the wind prone areas likely seeing gusts up
to 45-55 MPH Tuesday and early Wednesday, with gusts up to 40
MPH outside of the wind prone areas.
Temperatures will rebound slightly on Thursday as the next
Pacific trough moves across the southern Great Basin region.
This is when models start to diverge considerably as the speed
of this trough is nearly 24 hours faster with the GFS compared
to the less progressive ECMWF and Canadian. Thankfully, models
come into better agreement for next weekend as the strong Rex
Block over the eastern United States develops and remains in
place through the extended. There is high confidence with a
gradual cooling trend over southeast Wyoming and western
Nebraska Friday through next weekend, but confidence is limited
with precipitation amounts. This is pretty typical with
blocking patterns, and forecast confidence may not change much
over the next several days. Lower than average confidence is
mainly influenced by the strength of the Rex Block and exact
position when/where it develops. Gradually increased POP Friday
and Saturday for widespread rainfall, with the possibility of
considerable early season snowfall across the mountains above
9500 feet. With good ensemble support, kept the cooling trend
going towards the end of the week and next weekend with highs in
the upper 50s and 60s by next weekend. Can`t rule out the first
freeze of the season Saturday morning, but Sunday morning looks
more probable for areas west of the Laramie Range as another
strong upper level trough, this time digging south out of
western Canada, pushes across Montana and Wyoming with 700mb
temperatures lowering towards -3c by late next weekend.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 939 PM MDT Sun Sep 15 2024
Southwest flow aloft will continue. Scattered to broken clouds
from 8000 to 12000 feet will prevail. Winds will gust to
30 knots at Chadron and Sidney until 09Z, then gust to 25 knots
at the Wyoming terminals and Sidney from 15Z to 01Z, and gust
to 25 knots at Chadron and Alliance after 18Z.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...SF
LONG TERM...TJT
AVIATION...RUBIN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
619 PM CDT Sun Sep 15 2024
.KEY MESSAGES...
- Temperatures 5-10 degrees above normal through next weekend
with mainly dry conditions.
- Confidence on rain late this week and weekend continues to
lower with a potential blocking pattern developing over the
eastern CONUS.
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 221 PM CDT Sun Sep 15 2024
Isolated showers/sprinkles or even a thunderstorm are expected to
develop during peak heating this afternoon and dissipate with
sunset. Satellite shows developing cumulus mainly west of the
Mississippi and roughly concentrated in the I380/highway 218
corridors. Trends with the RAP have been pointing to this area for
possible diurnal convection late this afternoon.
Areal coverage of any convection that develops this afternoon looks
to be lower than yesterday so a majority of the area will remain dry
but somewhat humid.
After sunset quiet but somewhat humid conditions will be seen across
the area.
Another warm and somewhat humid day will be in store for Monday.
Although the signal is quite weak, another round of isolated showers
and possibly a thunderstorm may occur west of the Mississippi during
peak heating Monday afternoon.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 221 PM CDT Sun Sep 15 2024
Monday night through Thursday
Assessment...high confidence on above normal temperatures
If diurnal convection develops Monday afternoon it will quickly
dissipate with sunset leaving the area dry overnight. Otherwise the
upper level high retrogrades into the area which will keep the area
dry for much of the work week. IF a rogue SHRA/TSRA would develop
during peak heating during the afternoon hours, coverage would be 5
percent or less of the area.
Thursday night through Sunday
Assessment...high confidence on above normal temperatures. Low
confidence on rain chances
NHC probability guidance indicates Helene will have likely developed
earlier in the week and be a remnant low over the southeast CONUS by
late week. The system will help create a blocking pattern over the
eastern CONUS while a deep trof develops over the western CONUS.
The net result will be near meridional flow over the central CONUS
which will cause systems ejecting from the western trof to move more
north than east. This then raises the question regarding rain
chances from Thursday night into next weekend.
The trends with the QPF from the models and more of the ensemble
members has been to back off on the potential rainfall. Pops have
continued the trend of dropping but not as much as yesterday. Thus
the confidence on seeing any rainfall late this week and next
weekend is low.
Thus the model consensus does have 20-40 percent pops west of a
Freeport, IL to Quincy, IL from Thursday night through Saturday with
the better chances west of the Mississippi. However, with a
potential blocking pattern setting up I would not be surprised to
see the rain chances gradually lower during the week.
As for Saturday night and Sunday the model consensus has 20-35
percent pops for the entire area with the higher pops west of the
Mississippi. These pops continue the overall trend of going lower
compared to yesterday. Additionally, the predicted rainfall is also
lower as well which raises questions regarding the potential for
rain next weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 615 PM CDT Sun Sep 15 2024
VFR will continue tonight into Monday with light E to SE winds
and dry conditions.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...08
LONG TERM...08
AVIATION...Uttech
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1103 PM EDT Sun Sep 15 2024
.SYNOPSIS...
High pressure over New England and a developing low off the South
Carolina coast will maintain a gusty easterly wind flow over our
area into the early part of the week. The coastal low is expected to
drift north or northwest over the Carolinas bringing heavy rain to
the central and eastern Carolinas into mid week. The low may linger
before moving away from our region by next weekend.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 10:25 pm EDT Sunday: The broader area of precip (associated
with the potential tropical system just off the SE Coast) remains
well to our SE. The broad cloud shield associated with the tropical
system continues to gradually expand westward, and currently covers
roughly the eastern third of our CWA. I still can`t rule out a few
more brief, upslope showers developing in the ELY flow regime over-
night, but any coverage would be minimal at best. NE winds will re-
main gusty, especially over the Piedmont. Low temps should remain
at least a category above normal.
Otherwise, the coastal low which is now Potential Tropical Cyclone
8 per the Hurricane Center, is currently centered about 130 miles
off the coast of Charleston, SC, although it remains difficult to
actually locate a center of circulation as the system remains poor-
ly organized. The 18z operational GFS remains notably faster moving
this system inland on Monday and has it centered over the Columbia
area by roughly 00z Tuesday. Most of the other operational models
barely have the system over the SC Coast at this time. Regardless,
the general consensus remains more in-line with the more progressive
GFS solution with the center of the low moving onshore Monday evening
and turning more northward as it makes landfall. Expect deformation
zone moisture/forcing to wrap into our eastern zones during by this
time, with the outer precip bands moving over the I-77 corridor by
mid-afternoon with the potential for heavier rain increasing during
the evening hours. In contrast, our western/southwestern zones only
carry a slight chance PoP at this time. A significant gradient remains
wrt QPF amounts across our CWA, with the I-77 corridor still expected
to see roughly 2 to 4 inches from Monday thru early Wednesday, while
most of the Upstate and NC mtns will see half an inch or less. These
amounts could change significantly going forward depending on how
fast this system moves over our area. The other main concern will
be the gusty winds. Much of the short-term guidance still depicts a
40+ kt 850mb jet developing N to NW of the cyclone center on Monday.
Gusts of 30 mph, and perhaps some occasional gusts of 35+ mph are
still expected across the NC Piedmont Monday afternoon and evening.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
As of 230 PM Sunday: An unusual amount of uncertainty remains in
the short term forecast given the much discussed low pressure
system off the Carolina coast, though consensus appears to be
building for at some notable impacts gusty winds and moderate
to isolated heavy rainfall) to the northeastern half of our CWA.
The timeframe for these impacts will likely include the beginning of
the period Monday night into early Tuesday or Tuesday afternoon.
The 12Z GFS has not appreciably changed its solution from the
06Z run, bringing a surface low across NE SC toward the Charlotte
metro by early Monday evening then quickly weakening the low and
propagating it into the eastern Ohio Valley later Tuesday, as
the parent upper low becomes trapped under an expansive longwave
ridge over the eastern ConUS. There is general agreement in
the GFS ensemble suite and increasing support from CAM guidance,
including the 12Z HRRR and HRW, that areas along and to the north
and east of the surface low will at least see a swath of moderate
rainfall (generally 1-2 inches) with isolated heavier totals of 2-4
inches possible through Tuesday evening. An ensemble of CAM and
NationalBlend guidance suggest 40-80% probabilities of storm-total
rainfall exceeding 2" across the northeastern half of the CWA,
with the highest amounts focused along and near the I-77 corridor.
This rainfall is expected to fall over roughly a 12-18 hour period,
and with probabilities of 6-hour rainfall expected to exceed 2"
or more of about 20-40% over the Charlotte metro, if the guidance
pans out, an isolated flash-flood threat would be anticipated.
The areas that need the rain the most, across the western half of
the forecast area, are the least likely to see appreciable rainfall
from this system.
Not to be outdone, the pressure gradient between any surface low
and ~1027mb high pressure centered off the New England coastline
suggests strong wind gusts will persist into Tuesday morning as
well. HREF probabilities of 30-50% for wind gusts greater than 45
mph (Wind Advisory criteria) across much of I-77 and adjacent I-40
corridors suggests we will have to monitor the forecast closely.
Although high-resolution guidance tends to overforecast winds,
these probabilities suggest winds will nevertheless have an notable
impact through the Tuesday morning commute. The strength of wind
gusts will be dependent on the presence and eventual strength of the
surface low, and again, despite being 24-36 hours out, there remains
the potential of significant shifts either west or east in the axis
of greatest impacts as well as in the severity of those impacts.
Conditions will improve rapidly later Tuesday into Wednesday, as
whatever materializes for Monday night is expected to occlude if
not dissipate well to our north, leaving the area on the southern
edge of a large closed-low with the best moisture and forcing
displaced to our north and east. Nevertheless, attendant lapse
rates and weak areas of vorticity rotating around the closed low
support slight chance to chance PoPs for widely scattered showers
through the period. Skies should remain mostly cloudy or overcast
on Tuesday with high temperatures 5-7 degrees below normal across
the northeastern half of the CWA. High temperatures further
west and away from any surface low are expected to be normal
to slightly above normal under partly sunny skies. With skies
gradually becoming partly to mostly sunny by Wednesday afternoon,
highs should return to near normal.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 230 PM Sunday: The deterministic guidance is in general
agreement that the closed upper low will gradually propagate
south and east toward the Southeast coast through the rest of
the work week, possibly getting absorbed into a longwave trough
on the eastern side of a developing Omega block over the western
two-thirds of the ConUS. Heading into the weekend there remains
decent agreement that an upper low will become separated from
the longwave pattern and close off near Florida as upper-level
ridging builds over the Ohio Valley and Great Lakes, evolving the
Omega block into a Rex blocking pattern. The evolution of this
upper-level pattern suggests that isolated to scattered showers are
possible, especially across the northern half of the CWA, as the
upper low drops south and east through the Carolinas on Thursday
and Friday. Meager but non zero instability suggests a few isolated
thunderstorms cannot be ruled out each afternoon. The pattern and
partly cloudy skies suggests seasonable high temperatures both days.
By next weekend, the forecast area is expected to be north and
west of the mean trough axis, placing us in a more stable and
drier airmass. Surface high pressure centered over southern Quebec
on Saturday, with a weak surface trough axis located just off the
Carolina coast, suggests a decent pressure gradient and support for
a wedge-like pattern across the CWA Saturday night and persisting
through perhaps Monday. In response, blended guidance supports
highs at least several degrees below normal at the end of the
period on Sunday under partly sunny (southwest) to mostly cloudy
(northeast) skies and within a stout northeasterly flow.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: With the relatively moist ELY flow expected
to continue above the surface, cigs will likely drop to the low-end
MVFR range around daybreak Monday. They will likely improve somewhat
during the afternoon over the Upstate sites and KAVL, however they
will likely drop into the IFR range for KCLT and possibly KHKY as
the broader area of precip associated with the coastal low spreads
over the I-77 corridor during the aftn. As such, I have prevailing
rain at KCLT beginning around 19z and continuing for the rest of the
taf period along with visby and cig restrictions. In addition, I have
included a few hours of low-level wind shear at KCLT later tomorrow
evening as the center of the low approaches the area. At KHKY, I have
prevailing rain beginning around 22z on Monday, but I kept cigs at
low-end MVFR thru the end of the period. The other taf sites are less
likely to see prevailing showers, so I only have VCSH for them thru
24z Monday. Winds will remain gusty and from the NE thru the period.
They will likely intensify late Monday morning as the low approaches
our area with gusts in the 20 to 25 kt range. Gusts in the 25 to 30 kt
range are likely at KCLT on Monday afternoon/evening, with some gusts
possibly exceeding 30 kts.
Outlook: Gusty winds will continue to impact the area into early
Tuesday. Based on the current fcst, the heavier showers associated
with the coastal low are more likely to impact KCLT and KHKY than
the other taf sites. Winds should weaken and precip should taper
off on Tuesday, with spotty showers and occasional restrictions
possible thru the remainder of the week.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JPT
SHORT TERM...JMP
LONG TERM...JMP
AVIATION...JPT
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
600 PM CDT Sun Sep 15 2024
.KEY MESSAGES...
- Summer-like warmth continues through the week with highs peaking
in the middle 80s to near 90 degrees with a fair amount of
sunshine.
- An isolated shower or thunderstorm (20% chance) is possible into
early evening from Galesburg to Jacksonville west, but most of
central and southeast IL will stay dry and warm this week.
&&
.DISCUSSION...
Issued at 300 PM CDT Sun Sep 15 2024
A 1026 mb high pressure ridge over southern New England and
ridging westward across the Great Lakes region and into central
and northeast IL was bringing in drier air into the CWA. Dewpoints
ranged from the mid to upper 50s in eastern IL, to the low to mid
60s from I-55 west. Warm temps were in the mid to upper 80s over
CWA with Springfield at 90F. Scattered cumulus clouds and tufts
of cirrus clouds was giving partly sunny skies overnight at mid
afternoon. Scattered showers and thunderstorms were sw of I-64
near St Louis. Aloft a strong 590 dm 500 mb high pressure was over
the eastern Great Lakes and ridging westward toward Lake MI and
ne IL.
A few of the latest CAMs models like the HRRR shows isolated
convection developing over west central IL near Scott and
Schuyler county late this afternoon and early evening and sets up
again Monday afternoon but further west of CWA. Continue slight
pops until sunset from Jacksonville west and kept Monday dry
across area. Latest CAMs also not showing much fog development
over CWA overnight and mainly over river valleys in MO and
possibly lower IL river valley. Temps a bit cooler tonight with
lower dewpoints in area today, with lows in the lower 60s, with a
few upper 50s in east central IL. Very warm again Monday with
highs in the upper 80s to near 90F and dewpoints slipping into the
mid to upper 50s, with lower 50s possible in east central IL.
Partly to mostly sunny skies Monday with more cumulus clouds over
the IL river valley.
A tropical system off the southeast Atlantic coast will track nw
into the central Carolinas later Monday, with a cutoff mid/upper
level low over the central Appalachians Tue night and Wed and
weakening and pulling away into mid Atlantic States Thu. Blocking
Rex upper level pattern keeps this system well east/se of IL with
its precipitation likely east of Indiana next few days. Ample
sunshine Tue with highs in the upper 80s with dewpoints in the low
to mid 50s and light ENE winds.
A strong upper level trof along the West Coast to slowly emerge
over the Rockies by mid to late week and have a frontal boundary
moving into the upper MS river valley and Central Plains by weeks
end. It`s convection appears to stay west and nw of CWA through
at least Saturday. Blended forecast has 20-30% chance of
convection moving into the IL river valley Sat night and Sunday
(next weekend). Highs in the mid to upper 80s Wed and upper 80s to
near 90F Thu through Saturday.
The Climate Prediction Center (CPC) 6-10 Day outlook for Sep
21-25 has 70-80% chance of above normal temperatures over central
IL. CPC`s 8-14 Day outlook for Sep 23-29 has 55-60% chance of
above normal temperatures over central IL, so looks like September
will end up warmer than normal and likely drier than normal too
as drought likely expands northward from southern IL.
07
&&
.AVIATION... (For the 00z TAFs through 00z Monday Evening)
Issued at 600 PM CDT Sun Sep 15 2024
High pressure off to our east will keep VFR conditions in place
again this forecast cycle. Expect SCT-BKN high clouds and light
east winds.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
541 PM MDT Sun Sep 15 2024
.KEY MESSAGES...
- Showers and thunderstorms will be possible into the evening, with
an isolated severe threat across far southeastern Colorado.
- The chance for showers and thunderstorms will increase on
Monday for the San Juans and San Luis Valley.
- Strong to severe storms possible Tuesday afternoon, mostly
across the eastern plains.
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 232 PM MDT Sun Sep 15 2024
The latest mid-level analysis indicates that a trough axis is
centered along the Pacific NW coast with the local area in a moist,
southwesterly flow ahead of this feature. East of the area, weak
ridging is in place over the central and southern Plains. The latest
relative humidity time-height cross section for Pueblo indicates a
dry layer from the surface up to around 500mb. A RAP sounding for
KPUB shows this well with an inverted V signature from 525mb down to
the surface. The latest satellite imagery and radar show convection
developing from the San Luis Valley eastward to SE Plains with
partly cloudy skies across much of the area.
This evening and tonight, the trough and its associated closed low
will slide southward into northern California and the mid-level
ridge keeps its strong hold across the southern and central Plains.
This will leave the local area in a southwesterly flow between the
two features. Instability will be relatively weak for thunderstorms
this evening (in the 500-1000 J/kg), but enough to provide
instability for the possibility of isolated thunderstorms. A strong
to severe wind threat cannot be ruled out given the inverted V
signature indicated by RAP model soundings. Showers and storms will
mostly diminish overnight everywhere except the San Juan Mountains.
For the San Juans, deeper moisture will advect into the area from
the southwest, allowing for the chance (30-50%) of showers and
thunderstorms to continue overnight and trend upward to be more
likely (60% probability) near dawn on Monday. The snow level will
drop to around 13,500 ft, so not out of the question some of our
highest peaks will see some snow mixing in late Sunday night into
Monday morning.
On Monday, mid-level moisture will stream into the area from the
southwest, increasing cloud coverage and showers and thunderstorm
chances with fuel from day-time heating. Instability, for the
majority, appears weak (<500 J/kg SBCAPE) and shear is marginal (25-
30kts 0-6km bulk shear). Thus, showers and thunderstorms should be
most likely over the San Luis Valley and San Juan Mountains with the
best access to monsoonal moisture, with lesser chances eastward to a
nearly dry forecast for the extreme southeastern Colorado.
For temperatures, the forecast is closest to the National Blend of
Models. Lows tonight will range from the lower 60s in SE Colorado to
the lower to mid 50s along the I-25 corridor to the mid 40s in the
San Luis Valley to the 30s in the highest terrain. On Monday, areas
across the Plains of far southeastern Colorado will see the warmest
temperatures closer to the ridge with some locations warming into
the lower 90s. Temperatures will be progressively cooler westward,
in the 80s along the I-25 corridor, in the upper 60s to lower 70s in
the San Luis Valley to the 40s and 50s across higher terrain. /04-
Woodrum/
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 232 PM MDT Sun Sep 15 2024
Monday Night: Monday evening and night will bring some active
weather to portions of south central and southeastern Colorado. An
amorphous wave will be exiting the region, with moist southwest flow
persisting behind the wave. While broader forcing will lessen,
orographic forcing will continue given the rising southwest flow.
With broader forcing decreasing, most showers and storms across the
region are expected dissipate during the evening hours and much of
the area will remain dry. The exception to this will be along the
mountains, particularly the San Juan Mountains, where orographic
forcing will persist given the increasing southwest flow and
increasing moisture. While only mostly showers are expected,
occasional rumbles of thunder and thundershowers are possible given
minor instability remaining overnight. Otherwise, mild temperatures,
relatively light winds, and partly cloudy skies are anticipated.
Looking at temperatures, much of the region will remain mild and
above seasonal values overnight given downsloping winds and cloud
cover.
Tuesday: Tuesday brings an uptick in active weather for much of
south central and southeastern Colorado. A closed low to the
northwest of the region will quickly eject to the northeast
throughout the day. While the core of this feature will remain to
the northwest and north of the area, strong synoptic and orographic
forcing is still expected as the southern fringes of the low passes
over. Along with that, a moisture plume will advect northward ahead
of the primary larger wave. With the surge in forcing and moisture,
there is high to very high (70-90%) confidence in scattered showers
and storms throughout the day. Showers and storms will initially
blossom along the Continental Divide area during the morning hours,
and then push eastward, following the strongest forcing throughout
the day. A few strong, to possibly severe, thunderstorms are
possible, especially across the eastern plains, during the afternoon
hours when moisture, instability, and shear will be maximized. The
most likely hazard with any stronger storms will be strong outflow
winds given DCAPE values around 1000-1200 J/kg, but also due to
mature thunderstorm downdrafts mixing stronger winds aloft to the
surface. With that all said, as the low/wave continues to rapidly
eject to the northeast and exit the region, forcing will quickly
lessen, and any showers or storms present across the area are
anticipated to dissipate during the evening hours. Otherwise during
the day, warm temperatures, windy conditions, and partly cloudy
skies are expected. As for temperatures, areas generally along and
east of the I-25 corridor will hover around and slightly above
seasonal values given less clouds, while areas generally west of
there will hover around and slightly below seasonal values given
early daytime cloud cover.
Wednesday - Thursday: For part of the midweek period, a period of
quieter weather is anticipated. Southwest flow will reestablish over
south central and southeastern Colorado, though drier air will be in
place behind the Tuesday storm system. So while orographic forcing
will continue, the drier air will limit precipitation development,
and given that, dry conditions are expected for much of the region.
The exception to this may be a highly isolated shower or two along
the mountains, though mostly on Thursday. The greatest concern for
Wednesday and Thursday will be returning critical fire weather
conditions. Given the drier conditions and breezy winds persisting,
critical fire weather conditions may materialize for portions of the
lower elevations, though confidence is low (20-30%) in timing and
areas of greatest concern at this time. Outside of that though, warm
temperatures continue, with breezy winds, and scattered afternoon
clouds. Focusing on temperatures, the warmth does continue. Most of
the region will remain above seasonal values for mid September.
Friday - Saturday: For the end of the week and start of the weekend,
active weather makes a return to south central and southeastern
Colorado. Synoptically the broad trough that brought the Tuesday
system will finally push eastward, bringing another wave during this
timeframe. Ensemble model guidance are in relatively good agreement
about this, leading to at least medium to high (50-70%) confidence
in this pattern evolution. With the uptick in forcing, and despite
moisture remaining limited, showers and thunderstorms are expected
to increase in coverage, especially along the mountains where
forcing will be greatest. Besides that though, cooler temperatures,
relatively lighter winds, and periods of cloudy skies are
anticipated. Looking at temperatures, yep a cool down is expected.
Friday will hover around seasonal temperatures, with temperatures
dropping below seasonal values Saturday as the system pushes
overhead and shoves a cold front southward during this period.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 541 PM MDT Sun Sep 15 2024
VFR conditions are expected at all three TAF sites, KCOS, KPUB, and
KALS, for the next 24 hours. Winds will follow normal drainage
patterns at night, and will be primarily southwesterly tomorrow
afternoon, with gusts to around 22-25kt at KCOS and KPUB. Showers
and thunderstorms will be possible in the vicinity of KALS and KPUB
tomorrow afternoon, especially after 18Z at KALS and 21Z at
KPUB.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...WOODRUM
LONG TERM...SIMCOE
AVIATION...EHR
Area Forecast Discussion
National Weather Service Sacramento CA
107 PM PDT Sun Sep 15 2024
.Synopsis...
Cooler and more unsettled weather thru mid-week with a chance of
showers and thunderstorms tonight into tomorrow morning. Dry and
warmer weather returns late in the week.
&&
.Discussion...
Satellite this morning shows some a line of cumulus and high
clouds over Northern CA, ahead of the weather system moving down
from the Pacific NW. Radar returns showed some virga over the
northern half of the CWA, evident of the increasing moisture
moving into the area.
Chances for showers and thunderstorms are projected to begin over
the northwestern portions of the CWA near the Coastal Range and
adjacent are this evening before another push of rain over the
Sierra late Monday morning through Monday evening. Showers will
be scattered in nature with best chances for thunderstorms across
the Coastal Range and the western portions of Shasta, Tehama, and
Glenn counties from this evening to Monday morning (15-30% chance
of thunderstorms). The 12z HRRR run shows showers tapering off by
early Tuesday morning. For total rain amounts from this evening to
Monday night, NBM probability shows a 40-75% chance of amounts
greater than 0.25", highest over the Southern Cascades.
With this, there is also the potential for some snowfall at the
higher elevations of the Sierra above 7000 feet. Warm roads may
mitigate any significant accumulations and is not expected to
impact major roadways.
After Tuesday morning, things quieten with a brief reprieve from
active weather before another weather system moves in from the
northwest Tuesday evening through Wednesday night. This will bring
another round of scattered showers and isolated thunderstorms
with breezy winds near storms. NBM forecasts 0.50-1.00" over the
Sierra and 0.10-0.50" elsewhere with a 15-25% chance of
thunderstorms over the Sierra. There is a 40-70% chance of amounts
over 0.50" across the Sierra north of I-80 on Wednesday.
Temperature highs will continue its cool trend with highs in the
upper 70s to low 80s through Wednesday before temperature begin to
warm back to normal.
&&
.EXTENDED DISCUSSION (Thursday THROUGH Sunday)...
Ensembles continue to vary slightly on the timing and movement of
an upper level low as it progresses through interior NorCal. The
NBM still favors the slower EC ensemble, which will keep shower
chances in the Sierra Nevada throughout the day on Thursday. The
best chances will be along and south of I-80, with the NBM
advertising around a 10-40% chance of rainfall totals greater than
0.25" inches on Thursday. Locally breezy to gusty northerly winds
may develop Thursday as well as the trough continues to slide off
towards the east and ridging builds in the eastern Pacific.
Friday, ridging continues to move inland and as a result high
temperatures will climb into the low to mid 80s and continue to
warm as we move into the weekend. Ridging may also inhibit the
Delta breeze from cooling Delta breeze influenced areas over the
weekend as well, with high temperatures climbing into the low 90s.
As we warm, the area should also be free from any precipitation
chances Friday through Sunday.
&&
.AVIATION...
MVFR/IFR conditions spreading across interior NorCal through the
forecast period . Isolated tstms possible N of I-80 aft 21z. In
Central Vly, areas of Sly sfc wind up to 15 kts. Vcnty of Delta,
SWly sfc wind 15-25 kts with local gusts to 35 kts. Over hyr trrn,
areas of SWly sfc wind gusts 30-40 kts.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$