Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/17/24
Area Forecast Discussion
National Weather Service La Crosse WI
1103 PM CDT Tue Jul 16 2024
.KEY MESSAGES...
- Pleasant weather ahead! A cooler, less humid, and drier
forecast through the rest of the week.
&&
.DISCUSSION...
Issued at 211 PM CDT Tue Jul 16 2024
A fairly nice start to the day with observations as of 2 PM showing
temperatures in the upper 70s to lower 80s and dewpoints in the
upper 50s to lower 60s. A bit of relief after a hot, humid, and
quite busy weather weekend. Satellite imagery and RAP progs show an
upper level trough which is forecast to move down across the Great
Lakes into Wednesday, with a wave currently moving across the
region. Hi-res models still produce some light echoes across the
area, with current radar starting to show some development in the
north. Have maintained low chances (15-25%) for some
sprinkles/showers this afternoon and early evening with weak CAPE
values looking to keep thunder chances lower as well. Otherwise, any
showers that do develop should diminish with the loss of daytime
heating.
An amplified upper level pattern will remain as a strong ridge holds
across the western U.S. and a trough over the east-central U.S.
through the week. At the surface Canadian high pressure looks to
dominate over the region bringing cooler conditions and less humid
air. Low spread between the 25th and 75th percentiles of
ensemble/blended model guidance supports near to below normal
temperatures with highs in the 70s to near 80 Wednesday through
Friday. A slight upward trend in temperatures is indicated for the
weekend into early next week, though highs are still forecast to
only top out in the mid 70s to low 80s. There remains low signal
among ensemble model solutions for any impactful precipitation
through much of the week, so have maintained a mainly dry forecast.
Some low rain chances return to the forecast for the weekend, but
confidence is low with the given pattern and low predictability
of any waves.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1103 PM CDT Tue Jul 16 2024
VFR conditions are expected through the rest of the TAF period with
scattered low to mid-level clouds. As we head into the afternoon,
winds will increase to around 10 kts remaining generally north to
northwesterly. Cannot completely rule out some valley fog at KLSE
early this morning with decoupling winds, however with winds
just off the deck to around 15 kts in the 16.21z RAP this
appears very unlikely (5-10% chance).
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...EMS
AVIATION...Naylor
Area Forecast Discussion
National Weather Service Cheyenne WY
548 PM MDT Tue Jul 16 2024
.KEY MESSAGES...
- Widely scattered storms possible this afternoon. Increasing
moisture Wednesday will support strong to possibly severe
thunderstorms Wednesday afternoon. Daily chances for
precipitation continue through the rest of the week.
- Warm mid-week before cooling trend begins for the weekend.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 230 PM MDT Tue Jul 16 2024
Latest radar scans showing isolated thunderstorms over the CWA
at 2 PM this afternoon. Cells are moving from north to south in
northwest flow. Latest RAP mesoanalysis showing around 500 J/KG
surface based CAPE. Cells don`t appear to have much vertical
growth . Still considerable lightning being observed with these
isolated storms...so we will continue to monitor.
Current PWATs over southeast Wyoming are quite dry...GFS showing
.6 to .8 inches over southeast Wyoming and .9 inches over the
Panhandle. Latest HRRR/RAP simulated radar shows convection
decreasing significantly after 01Z or so. SBCAPE does not
increase significantly through the late afternoon...so severe
storms are not a concern for the rest of the day.
Better chances Wednesday as low level winds shift easterly this
evening and draw low level moisture north from western Kansas.
Later shifts will need to be on the lookout for low stratus in
the Panhandle Wednesday morning for aviation forecasts. PWATS
increase to 1.27 inches in the Panhandle Wednesday afternoon to
near .9 inches here at Cheyenne. NAM/SREF/GFS showing pretty
widespread QPF over areas east of the Laramie Range Wednesday
afternoon. The outlier is the ECMWF that keeps the more
widespread QPF south in Boulder`s CWA. Afternoon MUCAPE in the
Panhandle up near 1500 J/KG. So could see a few severe storms
out that way.
Look for another round of showers and storms Thursday as low
level moisture remains in place through the day. Though less
than what we see Wednesday.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 335 AM MDT Tue Jul 16 2024
Upper-level ridging will develop once again over the western
CONUS Thursday through most of the long term forecast. This
ridge is progged to bring warmer temperatures to southeast
Wyoming and western Nebraska once again, but should be cooler
than this previous weekend. 700mb temperatures will only
increase to the 15C mark under the ridge on Thursday leading to
surface temperatures in the mid-80s to mid-90s. This ridge will
remain overhead for Friday as well, with a 500mb high centered
over the Four Corners region and advecting in monsoonal
moisture. Precipitable water will surge well over an inch for
portions of the Panhandle with closer to an inch over southeast
Wyoming. With several vorticity maxima traversing through the
ridge, precipitation looks likely both Thursday and Friday
evening, with Friday having the better chance for wider-spread
precipitation. As a result of the additional precipitation and
cloud cover expected for Friday, temperatures will be cooler in
the low-80s to low-90s across the region.
Saturday and Sunday both look cooler as the upper-level ridge
retrogrades slightly back to the west and colder air floods down
from Canada. Northerly to northwesterly flow aloft will remain for
both days, leading to the potential for precipitation chances in the
afternoons. A large fetch of northerly winds will be present from
southern Canada to northern Arizona, further promoting the cooler
temperatures. Temperatures on Saturday are expected to be in the
low- to upper-80s, with upper-70s to mid-80s expected Sunday. Kept
PoPs fairly low for these two days, between 20 and 30%, as afternoon
showers and storms will be difficult to track down at this time. The
cooler temperatures look to remain through the early week as the
strong northerly flow aloft remains.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 544 PM MDT Tue Jul 16 2024
A few showers and thunderstorms mainly over Wyoming are ongoing
at this time, but convection is dissipating elsewhere. While
there is a slight chance for a second round to develop around
KCYS, KBFF, and KSNY this evening, the probability is too low to
add to the TAF. There is also a slight chance for MVFR to IFR
CIGs moving into KAIA or KSNY around sunrise Wednesday, but
confidence is low at this time. Look for a nice morning
Wednesday, but scattered to numerous showers and thunderstorms
will begin developing by early afternoon.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...AM
AVIATION...MN
Area Forecast Discussion
National Weather Service Goodland KS
455 PM MDT Tue Jul 16 2024
.KEY MESSAGES...
- Severe chances during the late afternoon to overnight hours
with wind the primary hazard, but also a few instances of
marginally severe hail and flash flooding possible.
- Strong to severe storms are possible Wednesday into Friday as
well.
- Temperatures closer to normal beginning tomorrow and
continuing through the weekend.
&&
.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 219 PM MDT Tue Jul 16 2024
Across the region this afternoon, skies are a mostly sunny to sunny
mix, with a light/variable wind regime due to high pressure still
influencing the area. Temperatures are ranging mainly in the lower
to mid 90s.
The main wx concerns for the short term period will focus on storm
chances later this afternoon into this evening. And again Wednesday
through Friday.
With an elevated ridge over the western portion of the country,
several shortwaves are set to move along the eastern periphery of
the ridge and into the CWA. Today`s round of potential storms will
be aided by a stalled boundary that is currently draped along the
Oklahoma panhandle into eastern Colorado. The latest HRRR and
NamNest are showing storms cropping up by 22z-00z. Model track
focuses on the area south of I-70. The NamNest does continue to lean
on some areas north of I-70 still seeing 20-40% chances for rw/trw.
SPC currently has a Marginal Risk for severe over a good portion of
the CWA, with a Slight Risk still south of Highway 40 into Greeley
and Wichita counties. Inverted-v soundings still show wind as main
threat, but initial storms could give a brief hail threat as well.
WPC has an Excessive Rainfall outlook for locales along/south of I-
70. Slow movement of some of these cells, combined with PW values of
1.1 to 1.4 inches could give some locally heavy rainfall. Some areas
south of I-70 into Logan county did receive around 2.00" with storms
last night, so can`t rule out some isolated flooding issues if
training occurs as with last night. The bulk of storms should stay
south of the Interstate, but can`t rule out lingering precip
overnight north into Wednesday morning over the eastern CWA.
Going into Wednesday, surface ridge north shifts east of the CWA,
with a lee-side trough setting up over the eastern Rockies. Aloft,
the upper ridge remains in place with yet another shortwave working
off the Rockies into the CWA. Latest guidance starts things west
around 18z and pushes a bit eastward to at least Highway 25 at best
as blocking effects prevent any further eastward push into the
afternoon and evening. Late evening though, the ridge gives way east
allowing for any remaining rw/trw to drift east towards 12z
Thursday. SPC does show a Marginal Risk for severe wx for locales
along/west of Highway 25. Instability warrants mention of high wind
threat once again, although hail could be initially as storms form
in Colorado. WPC has a Marginal Risk for excessive rainfall in
Colorado as here lies the best chance for persistent heavy rainfall
due to the slow moving storms expected.
On Thursday, chances for storms through the first half of the day
with the western CWA seeing best chances(20-30%) for storms. The
shortwave expected for Thursday is a bit weaker than Wednesday and
coming from the north due to amplification of the ridge into the
Rockies. Guidance carries 20 pops going into the evening hours
before things taper by 06z Friday. There is a Marginal Risk for
severe for Thursday afternoon and evening in the northwest, but
storms set to weaken as the evening progresses with a wind threat
once again.
Going into Friday, a brief reprieve over the area as high pressure
sets up east of the CWA, with a strong lee-side trough over the
eastern slopes of the Rockies. Another shortwave(500-700mb) dives
southeast Friday afternoon into the evening for another round of
storms, with better areal coverage due to ample low level moisture
inflow/instability. 40-60% chance for storms is in place Friday
evening as the system pushes through. Looking for wind/hail threats
as well as potential for heavy rainfall again due to high PW values
around 1.2" to 1.6".
For temps, highs in the short term period will see an increasing
trend with midweek numbers ranging in the lower to mid 80s. On
Thursday, warmer with mid to upper 80s expected, and for Friday,
lower to mid 90s. Overnight lows will range widely from the upper
50s into the mid 60s. Warmest night will occur Thursday night where
all areas will be in the 60s.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Issued at 135 PM MDT Tue Jul 16 2024
Looking at the latest runs of the GFS and ECMWF, both models do
carry an amplified 500 mb ridge over the western portion of the
country. A trough swings through the northern/central Plains during
this time. Models do differ as to the system forming a meandering
cutoff low or staying as a trough. From previous runs it does look
like consensus for a cutoff low forming in the 500/700 mb range,
meandering slowly over the central Plains.
At the surface, a front will settle south of the CWA going into
Saturday, as a strong ridge works into the northern Plains. The
placement of the ridge will play a key role in amount/chances(20-
40%) for rw/trw potential each day. Areal coverage spans the CWA but
does trend westward due to the surface ridge building south into the
CWA by the beginning of next week.
The result of this will have storms chances peaking late in the
weekend into next Monday, before shifting towards the west. The
caveat for the extended forecast will be the potential for heavy
rainfall. PW values will range from 1-1.5" w/ best numbers in the
east as surface winds shift easterly late in the period.
For temps, looking for highs to start off the upcoming weekend to
range in the mid to upper 80s on Saturday, giving way to slightly
cooler numbers on Sunday with upper 70s to mid 80s expected. Going
into next week, conditions begin an upward trend with mainly lower
80s Monday, mid to upper 80s for Tuesday.
Overnight lows will range mainly in the mid to upper 50s this
weekend. A few spots east of Highway 83 will reach the 60F mark.
Next week, a similar setup to this weekend with mid and upper 50s
Monday night, then a range from west to east Tuesday night from the
upper 50s to lower 60s. Warmest along/east of Highway 25.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 455 PM MDT Tue Jul 16 2024
KGLD...VFR conditions are expected through the period. A
northeasterly wind around 10kts at taf issuance will veer to the
southeast then south at similar speeds overnight. On Wednesday,
light and variable winds in the morning become easterly at
speeds up to 10kts or so with perhaps a few higher gusts.
Presently, convection well west of the area is forecast to move
to the southeast and should remain out of the area. There could
be outflow wind gusts to 30kts or so in the 02z timeframe.
KMCK...VFR conditions are expected through the period. Winds
will generally be from the east around 10kts through the period.
Will keep shower/thunderstorm mention out of the forecast at
this time. Will be watching for the potential for storms to
impact the terminal from the northwest in the 02z-06z timeframe.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...JN
LONG TERM...JN
AVIATION...99
Area Forecast Discussion
National Weather Service Gray ME
946 PM EDT Tue Jul 16 2024
.SYNOPSIS...
Heat and humidity build continue through Wednesday as high
pressure strengthens off the Eastern Seaboard, with chances for
scattered afternoon or evening showers and thunderstorms each
day. A cold front moves through late Wednesday through Thursday,
bringing drier and somewhat cooler conditions for the end of
the week and going into the weekend with high pressure building
in from the west.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
945 PM Update...The line of severe thunderstorms that brought
damaging winds across southern NH into SW Maine has now
weakened below severe thresholds as it encounters stable air
across western Maine. The Severe Thunderstorm Watch has now been
canceled. Have mainly fine tuned PoPs and removed enhanced
wording for thunderstorms with this update. Showers with
embedded thunder will continue to push east into central Maine
while precipitation has mostly ended across southern NH.
615 PM Update...A Severe Thunderstorm Watch has been
issued for much of New Hampshire into York and Cumberland
Counties in Maine. A well developed QLCS is crossing into
southern VT and is progged to reach the Lower CT Valley around 7
PM. This line of strong storms has history of producing wind
gusts in excess of 70 mph. Latest guidance from the HRRR and
WoFS suggest this QLCS will maintain its strength as it crosses
Cheshire and Sullivan Counties and will start to weaken as it
crosses NH into SW Maine while still posing a damaging wind
threat into SW Maine. In addition to damaging winds, 0-3 km
shear orthogonal to the bowing segment will bring the threat of
a QLCS spin up. This line of storms will reach the ME/NH border
around 9 PM and will move offshore around 10 PM.
Previously...
For tonight, early focus is on developing MCS over central NY
this afternoon, which should strengthen as it moves east, and
move into central/southern NH around 23Z . The timing of this
system is better for severe than last night, but also, it looks
to be organized than last nights system with CAMs developing a
cold pool behind the convective line and possibly a rear inflow
jet. It will likely peak over S VT but the system should
continue to blow itself out as it crosses NH, so some damaging
winds will be possible, and the SPC slight risk area seems like
a reasonable approximation of where the threat is the greatest.
The system should be off shore of ME by 02Z and I dont see any
sever threat beyond this time as well, but a cluster of
thunderstorms will likely continue to move across the N zones
through about midnight. Patchy fog likely develops behind this
line overnight, with lows once again in the mid to upper 60s in
the N and around 70 in the S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
The subsidence and associated sfc high behind this system will
allow for a sunny start a a quick warm up Wed morning, and I
think convection in advance of the front will hold off until
around 18Z. This will allow for another hot and humid with heat
advisories issued over the same areas Tuesday except for
Cheshire county. Showers and Thunderstorms will be more
widespread in the afternoon and evening, and could see isolated
severe storms, with the best chance in southern NH again. Highs
reach into low to mid 90s in the S, with heat index in the mid
to upper 90s. The convection should help knock back the temps in
the mid to late afternoon, and therefore the advisory is only
until 22Z.
Likely wont get to see too much effect from the cold front Wed
night as the front slows around or just S of the CWA and the
threat of showers storms will linger, especially in srn NH and
near the coast through the night, as will the higher dew points
and fog. So lows will rage from the low 60s in the mtns to near
70 again in the S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A weak cold front will be in the process of crossing through the
area early Thursday with a continued chance of showers and
maybe a storm or two, mainly in the morning. After that, drier
air behind the front will make for mostly to partly sunny skies
going into the afternoon. There may be a couple of additional
afternoon showers, but the drier air/increasing subsidence aloft
will keep coverage low, and for this reason I have also removed
any mention of thunder during the afternoon hours. More
importantly it won`t be quite as hot with highs staying in the
80s south of the mountains, and dewpoints will also be lower and
in the upper 50s to lower 60s. More comfortable lows are on the
way for Thursday night thanks to the drier air, mostly clear
skies, and light winds. Most should see lows in the 50s with
upper 40s even possible across the northern valleys.
A period of pretty quiet weather is expected from Friday
through the weekend with high pressure largely in control along
with a dry airmass. There will be a chance of showers late
Saturday as a weak cold front crosses through, but this looks
mainly confined to northern areas, and moisture does not look
particularly favorable with this system at the moment. While
temperatures will be "cooler" than what we have been
experiencing lately, highs in the 80s are still forecast each
day, possibly close to 90 degrees for southern areas on Saturday
ahead of the frontal boundary. The silver lining is that
dewpoints will be lower to make the warm temps more manageable,
and temperatures will be able to cool off more at night. We`ll
probably have some valley fog at night/early morning, too.
Mostly dry conditions look to start out Monday of next week,
but after that global models are in pretty decent agreement
showing a broad low pressure approaching the OH Valley/Great
Lakes region. Out ahead of this system, moisture will be on the
upswing, and a warm front lifting northward toward New England
will increase chances for precipitation toward the end of the
forecast period (late Tuesday or even slightly beyond into
Wednesday). This is supported by the GFS/ECMWF ensembles, and
the NBM showing increasing PoPs on Tuesday looks good.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Expect a line of potential severe storms to move
through srn NH this evening, affect KMHT/KCON/KLEB, with heavy
rains, frequent lightning and potential W wind gusts to 50 kts
in the 23-01Z period. It is less likely to reach KPSM or KPWM,
but could still see heavy rain and frequent lightning here.
Otherwise patch fog could develop after midnight, especially
where it rained. However VFR returns by 12Z Wed, and should VFR
into the mid afternoon before another round of showers and
storms crosses the area through the evening. Fog and low cigs
will be widespread Wed night with a period of IFR-LIFR possible
at any terminals.
Long Term...Thursday may continue to see some degree of flight
restrictions in the morning with low ceilings a few showers and
storms, but conditions will improve to VFR by the afternoon.
Mainly VFR Friday through the weekend with the exception of
nighttime/early morning valley fog. A weak front approaching
from the north late Saturday could bring a few showers to
northern areas, but this would be primarily for HIE.
&&
.MARINE...
Short Term...SW flow persists tonight into Wed evening, and
could see gusts in the 20-25 kt range, but should stay below SCA
for the most part. Winds will shift to W and diminish Wed night.
Long Term...SCA conditions are not expected. A weak cold front
crosses the waters on Thursday, switching winds to NW to N later
in the day into Thursday night, but these will become onshore
by Friday afternoon as the seabreeze develops. Another weak
front crosses late Saturday and could result in another brief
wind shift to the NW. High pressure then settles over the waters
Sunday into Monday before low pressure brings increasing precip
chances by Tuesday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory from noon to 6 PM EDT Wednesday for MEZ012-
018>024-033.
NH...Heat Advisory from noon to 6 PM EDT Wednesday for NHZ004-006-
008>010-012>015.
MARINE...None.
&&
$$
SYNOPSIS...
NEAR TERM...Cempa/Schroeter
SHORT TERM...Cempa
LONG TERM...Combs
AVIATION...
MARINE...
Area Forecast Discussion
National Weather Service Louisville KY
956 PM EDT Tue Jul 16 2024
.KEY MESSAGES...
* Thunderstorms redeveloping overnight could cause locally gusty
winds and heavy rainfall.
* Cooler temps in the 80s for Thursday into the end of the week.
* Storm chances return early next week.
&&
.UPDATE...
Issued at 956 PM EDT Tue Jul 16 2024
Tricky forecast overnight with MCS and associated MCV coming out of
the Ozarks. For now we are left high and dry in the Ohio Valley,
with low confidence in the placement of any convection overnight.
Satellite imagery, sfc observations, and SPC mesoanalysis suggest
the most favorable areas for storms overnight will be roughly along
the Western Kentucky and Bluegrass Parkways. This is farther south
than previously advertised, and gets into areas with rainfall
deficits so far this summer rather than surpluses. Additionally, the
hi-res models suggest a more progressive look, resulting in precip
totals of less than 1 inch for most.
That being said, we do expect thunderstorms to fire around midnight
or just after, mainly moving across central Kentucky. Locally heavy
rainfall and minor flooding are still possible, but impacts should
be brief and limited. Therefore the Flood Watch will be cancelled.
&&
.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 301 PM EDT Tue Jul 16 2024
Plenty of convective cloud debris has hung around today, from both
the morning line of showers and storms, as well as from the
stationary cluster of convection over Illinois today. This cloud
cover has help limit our sfc heating, with most obs in the upper 80s
so far this morning. Less cloud cover over the Bluegrass has allowed
that area to warm into the 90s. Besides the Bluegrass region, heat
indices have not reached the triple digits, so the Heat Advisory
will be let go with this forecast package. It`ll still be very warm
and muggy this afternoon, specailly in the Bluegrass.
For the rest of this afternoon, a few isolated pop-up showers or
storms will be possible in an unstable airmass. The latest HRRR was
suggesting a few isolated cells over in the Bluegrass later this
afternoon, which is the area with the best heating today, so it
seems possible. Otherwise, the higher precip chances will come
tonight.
===== Tonight =====
A very slow moving frontal boundary will still be extending from
central Missouri to central Indiana tonight, but a very muggy
airmass ahead (south) of the front will support shower and storm
development overnight. While run-to-run consistency has been a
struggle, there is good agreement on our area having very high
PWATs, with over a 60-70% probability of exceeding 2 inches. While
QPF has come down slightly in today`s runs, the environment
overnight will be favorable for heavy rainfall, along with some
possible training as showers and storms line up and move parallel to
the frontal boundary to our north. The flood watch will remain as is
for now, especially given the concern for any nighttime flooding
from heavy rainers. As for the storm potential, most model soundings
depict elevated instability, with stable air in the lowest levels.
Not too concerned for severe risk tonight, but perhaps we could have
a few gusty winds with any stronger core that develops and results
in a water-logged downburst. The main timing for overnight activity
will be after midnight and before 12z tomorrow.
===== Wednesday =====
We`ll remain in the same type of airmass tomorrow, as the front will
still be to our north. PWATs will remain quite high, with another
round of isolated to scattered showers and storms for the day as we
become unstable in the afternoon. While we`ll have plenty of
instability for storms to work with, we will be lacking shear,
leaving most storms to be messy and unorganized. Soundings show a
bit more saturation in the columns, resulting in lower DCAPE values.
Will mostly expect garden variety storms tomorrow, but a few strong
storms could pack a punch of wind. Otherwise, overall severe threat
is low for tomorrow. Eventually the front will begin to make its way
through our area late in the day, but it will only make it to around
the Ohio River towards the end of the short term period.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 301 PM EDT Tue Jul 16 2024
By Wednesday night, the cold front should begin entering the
Commonwealth, draped roughly parallel along the OH River, as
isolated to scattered showers and thunderstorms out ahead of
the front begin to wane across the CWA with the setting sun. Cold
front is progged to be exiting our area by sunrise Thursday morning,
allowing for surface high pressure to build in across the region.
This will bring some relief to the recent sultry conditions, as
afternoon max temperatures reach into the low 80s Thursday while
increasing a couple degrees each day into the weekend. Drier air
will also result in surface dew points falling into the low 60s,
which is quite comfortable for July standards.
The aforementioned cold front stalls over the northern Gulf States
before beginning to waver back northward. Our area appears to remain
on the cooler side of this boundary through the weekend but close
enough to warrant slight chance mention of showers and possible
thunderstorms, mainly for areas south of the Parkways.
Chances of showers and thunderstorms increase going into the
beginning of next week as the OH Valley resides between synoptic
scale features: one being the cut-off low over the Central Plains,
next is the Bermuda high over the Atlantic, and last is our
position south of the wavering boundary. This set up will allow for
rich moist air advection along return flow and a destabilized
environment.
&&
.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 756 PM EDT Tue Jul 16 2024
VFR evening with W to SW winds diminishing after sunset. Main
challenge is timing and placement of storms developing overnight.
Look for convection to impact BWG beginning around 05Z, and pushing
east into LEX and RGA around 07Z. Will handle those with TEMPO
groups. Less confident in SDF as the focus is mainly south, but will
straddle daybreak with a PROB30 for storms. Heaviest part of the
storms will likely drop vis into IFR, but that will be brief so will
just go with low-end MVFR.
Low ceilings will linger well into Wednesday morning, perhaps with
some light precipitation, but expect the atmosphere to recover
around midday. Cigs should lift back to VFR, but the muggy air mass
and lingering boundaries will support enough of a storm chance to
warrant a PROB30 for TS/CB after 18Z. Winds generally due west
around 10 kt.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...RAS
SHORT TERM...CJP
LONG TERM...CRG
AVIATION...RAS
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
610 PM CDT Tue Jul 16 2024
...New AVIATION...
.SHORT TERM...
(This evening through Thursday)
Issued at 240 PM CDT Tue Jul 16 2024
The overall synoptic pattern had Arkansas was on the eastern edge of
an upper ridge this morning. The ridge is retrograding and
amplifying over the western US, which will result in a trof taking
its place over the midsection of the country. Ultimately Arkansas
will end up under a NW-W flow aloft.
A cold front will be moving out of the Plains and making its way
into Arkansas tomorrow. The front will take its time and may not
make it out of the forecast area until late tomorrow night into the
early hours of Thursday morning.
Thunderstorm chances will increase across the state tomorrow,
reaching the highest POPs tomorrow night.
The only lingering question is what the rain chances will look like
overnight into early tomorrow morning. NAM is rather aggressive
at developing showers and thunderstorms along outflow coming out
of MO/OK later this evening, and the HRRR follows suit, albeit
with the convection further north and with somewhat less coverage.
With that in mind, I have introduced some lower grade POPs further
south toward central AR by morning...faster than the NBM brings
anything into the area.
Last but not least, afternoon heat index values across the southern
counties tomorrow will top 105...so I went ahead and issued a heat
advisory for those areas.
&&
.LONG TERM...
(Thursday Night through next Tuesday)
Issued at 240 PM CDT Tue Jul 16 2024
Guidance remains in relatively good agreement this afternoon and any
changes to the extended period will be relatively minor. Confidence
remains on the higher side that temperatures will actually average
below seasonal average with at least some chances of precipitation,
especially in the latter part of the period.
Period starts with a highly amplified pattern in place that is
highlighted by upper ridging over the western CONUS and subsequent
downstream troughing stretching from the western gulf coast NE to
the eastern Great Lakes. Surface boundary forecast to be located
over northern Louisiana with ongoing chances of scattered showers
and thunderstorms over the south through Friday. Additional precip
amounts will be minimal with just a few hundredths of an inch
possible.
Front will remain quasi-stationary over northern Louisiana before
starting to retreat back to the north and stalling out over south
Arkansas Sunday. Most of the state, with the exception of the far
south, will be dry on Saturday before widespread precipitation
chances return on Sunday. Precipitation amounts are not expected to
be very high but some areas could pick upwards of a half an inch.
A slightly cooler but noticeably drier airmass will overspread the
region behind the front with both high and low temperatures below
average. Moisture levels will begin to increase as the boundary
moves north but temperatures should stay below average with
increased cloud cover and precipitation chances in place.
&&
.AVIATION...
(00Z TAFS)
Issued at 609 PM CDT Tue Jul 16 2024
Chances for convection increase late this afternoon and through
the evening hrs across NRN sections...then gradually shifting
south during the overnight/morning hrs for the central to SRN
terminals. By Wed afternoon...expect a break in precip...but
additional convection may redevelop during the heat of the
afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Batesville AR 73 87 68 84 / 70 80 60 30
Camden AR 76 96 70 86 / 10 30 60 70
Harrison AR 69 84 65 82 / 80 80 30 10
Hot Springs AR 74 94 70 85 / 30 50 70 60
Little Rock AR 75 91 72 84 / 40 50 70 50
Monticello AR 78 96 72 86 / 0 40 60 70
Mount Ida AR 73 93 68 84 / 30 50 70 50
Mountain Home AR 71 84 67 84 / 80 80 40 10
Newport AR 73 88 70 83 / 60 70 60 30
Pine Bluff AR 76 94 71 83 / 10 40 70 60
Russellville AR 73 90 70 85 / 60 60 70 40
Searcy AR 73 88 70 83 / 60 70 70 40
Stuttgart AR 74 90 73 82 / 20 40 70 50
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for ARZ004-052-053-056-
057-062>069-103-112-113-123-137-140-141-203-212-213-221>223-237-
240-241-313-340-341.
Excessive Heat Warning until 8 PM CDT this evening for
ARZ005>008-014>017-024-025-031>034-039-042>047-054-055-121-122-
130-138-230-238.
Heat Advisory from 11 AM to 8 PM CDT Wednesday for ARZ052-053-
062>069.
&&
$$
SHORT TERM...53
LONG TERM....56
AVIATION...62
Area Forecast Discussion
National Weather Service Morristown TN
1022 PM EDT Tue Jul 16 2024
...New UPDATE...
.UPDATE...
Issued at 1022 PM EDT Tue Jul 16 2024
Overall, the forecast is holding up well. The main change was
lowering the surface temperatures for tonight. This is due to the
widespread cloud cover across much of the region. This alongside
some scattered showers definitely inhibited the heating late this
evening. We can also expect some higher cloud coverage tonight
into tomorrow morning as indicated by satellite imagery. Chances
of precipitation rise throughout the morning, however the highest
chances are in the northern areas of our region and along the
mountains. Patchy fog is also possible, mainly in areas that saw
rain today.
&&
.SHORT TERM...
(This evening through Wednesday night)
Issued at 229 PM EDT Tue Jul 16 2024
Key Messages:
1. Isolated to scattered showers and thunderstorms this evening,
tonight, and Wednesday.
2. Increasing humidity will result in heat index values near or
over 100F.
Discussion:
To say that the short term forecast is uncertain would be an
understatement. There are many complicating factors to consider.
First, an upper-level jet will strengthen overnight with a jet
streak of over 100 kt. A strong shortwave will amplify troughing
across the Upper Mississippi Valley and Great Lakes, too. This
will enhance ascent across the Great Lakes and Ohio Valley with
increasing SW/WSW 850 mb winds in response.
At the surface, there is a defined outflow boundary near the
Interstate 40 corridor from early morning convection across
western KY. Ongoing convection along the deformation axis and
higher terrain of the plateau will also result in localized
outflow boundaries that will linger across the area overnight. As
WSW/SW 850 mb winds increase late tonight, this will increase
localized convergence along these boundaries with the potential
for isolated to scattered convection during the overnight and
early Wednesday morning time-frame. Confidence in timing and
location is very uncertain because of these mesoscale boundaries.
Shortwave vort maxima will lower heights across the region on
Wednesday with the potential for increasing coverage of isolated
to scattered showers and thunderstorms. A surface cold front will
shift southeast late in the day through Wednesday night with the
potential for scattered showers and thunderstorms along this
boundary. RAP forecast soundings are indicating MLCAPE of 2000 to
3000 J/Kg across the area on Wednesday with DCAPE of 800 to 1000
J/Kg. PW values will also increase late Wednesday ahead of the
front near 2.0 inches. This will produce a low severe risk with
localized strong wind gusts in addition to frequent lightning
and heavy rain rates. While not everyone will see abundant rain,
this is expected to be the most widespread convection across the
area in weeks.
&&
.LONG TERM...
(Thursday through next Tuesday)
Issued at 229 PM EDT Tue Jul 16 2024
Key Messages:
1. A frontal passage will keep widespread showers and storms across
the area through Thursday.
2. A break from the heat is expected behind the front, with slightly
below normal temperatures Thursday through Tuesday. Good chances for
rainfall will return late Friday into Saturday and again Sunday
through Tuesday
Discussion:
At the beginning of the extended forecast A cold front will be over
or near the forecast area ahead of a large upper trough moving south
from the northeast states. The big forecast question for the
beginning of the extended forecast is how far south does the frontal
boundary move Thursday. If it is still in the vicinity expect
another day of widespread showers and storms. However, if it pushes
too far south then the bulk of the precip will be to the south and
we will be much drier. NBM POPs suggest the front is still in the
vicinity Thursday so will continue with that trend. Storm total QPF
ending Thursday has most locations around 1 to 1.5 inches of much
needed rainfall.
After Thursday the front will have shifted south but shortwave
energy moving through the upper flow and south to southeast flow off
the Gulf of Mexico will keep a chance of showers and storms in the
afternoon and evening Friday...higher near the mountains. Models
want to bring a surface low along the front into Alabama later
Friday and lift it northward Saturday. As the front lifts back north
through and over the forecast area and eventually remain stationary
Saturday, rain chances increase. The moist flow will keep diurnal
afternoon and evening showers and storms across the region through
Sunday. Rain chances will be highest in the eastern mountains and
lowest northern plateau and Virginia through Sunday. Highs Thursday
through Sunday will be a few degrees below normal and mainly in the
lower 80s northeast to mid and upper 80s central and southwest.
For Monday and Tuesday the frontal boundary lifts farther north into
the Ohio Valley Monday and Tuesday as the Bermuda high stays strong
along the southeast coast. There still should be elevated
precipitation chances due to higher than normal moisture values
across the area. The position of the High pressure area helps Gulf
moisture stream into the southeastern U.S. The convection will be
driven by daytime heating. Temperatures the last two days of the
extended forecast will be slightly below normal during this time.
High temps will generally be in the mid 80s to upper 80s.
&&
.AVIATION...
(00Z TAFS)
Issued at 718 PM EDT Tue Jul 16 2024
Currently, there are showers and storms west of TYS and TRI. It is
unclear if they will hold together and/or make it to the terminals
overnight. The current indications are for them to fall apart with
little impact. Based on this trend, VFR is expected to prevail
with fog development mainly being in places that saw rain
measurable rain today. Shortly after sunrise, there are
indications for additional shower development around TRI that
could create MVFR conditions, but confidence is limited. Through
the afternoon, southwesterly winds are expected with some higher
gusts at TYS and TRI. Late in the afternoon, scattered storms are
likely to approach the terminals, but timing is uncertain.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 73 94 73 89 / 20 80 70 80
Knoxville McGhee Tyson Airport, TN 73 91 71 85 / 50 80 80 80
Oak Ridge, TN 71 91 71 84 / 20 80 80 70
Tri Cities Airport, TN 69 89 69 80 / 60 90 80 70
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...BW/HD
LONG TERM....TD
AVIATION...BW/HD
Area Forecast Discussion
National Weather Service Pocatello ID
219 PM MDT Tue Jul 16 2024
.SHORT TERM...Today through Wednesday Night.
The heat is back on today and tomorrow as highs continue to slowly
rise. Many will go from the upper 80s to low and mid 90s this
afternoon to more widespread low to mid 90s on Wednesday afternoon.
Even though high pressure is generally in control, it has slipped
just far enough to our southeast and will be flattened just a bit
more by a shortwave trough moving into the PNW tomorrow. This will
allow some monsoonal moisture to creep into our area. The best
chance, about a 10 to 20 percent chance, for that today will be
along the Wyoming state line. Wind gusts today are expected to be
"typical" afternoon gusts around 15 to 20 mph through the eastern
Magic Valley and Snake Plain. Gusts associated with any convection
we can get going would be closer to the 30 to 40 mph range. As for
continued haze across the area and any smoke impacts, the HRRR is
showing reduced visibility tonight down to about 3 to 7 miles
through parts of the Wood River valley, eastern Magic Valley, and
lower Snake Plain from the Bench Lake fire. The NAM and NBM don`t
seem to be picking up on this at all, but the HRRR generally does a
bit of a better job in this aspect. So, we will see how that pans
out overnight to get a better feel for model verification (and a
reality check on my own bias). The potential for isolated afternoon
convection continues on Wednesday for parts of the Eastern
Highlands, but also for portions of the Magic Valley, South Hills,
and Central Mountains. These will likely be dry storms again, as
monsoonal moisture is quite limited, but convective-related wind
gusts will be in the 35 to 45 mph for many. This may push closer to
50 to 55 mph in parts of the Magic Valley and South Hills.
AMM
.LONG TERM...Thursday through Tuesday.
The long term pattern remains relatively unchanged. Ensemble
clusters maintain ridge of high pressure over the Great Basin
throughout. Weak moisture rotating around the ridge may provide
for isolated mainly higher elevation thunderstorms each day.
Forecast temperatures remain stable, still hot but generally below
our recent excessive heat event. There may be a few zones that
flirt with Heat Advisory conditions, but relatively cool low
temperatures below 65 degrees MOST areas will mitigate some of the
potential.
DMH
&&
.AVIATION...There is still a minor potential for convection, with
the main threat until about 02Z for KDIJ, and even less so for KIDA.
Outflow potential to about 30kts. That said, not sure there is
enough confidence to include VCTS at either location. Some of the
high res model solutions also depict weak overnight convection.
Again, not enough confidence to include any mention at this time.
The main overarching concern will be smoke impacts. Satellite
imagery shows widespread swath of smoke/haze from upstream
wildfires. HRRR Smoke has been persistent and robust with smoke
influence impacting KSUN overnight under downslope northerly flow
regime. Have brought KSUN down to at least MVFR VSBY overnight, with
expectations for occasional IFR. KBYI also likely to see occasional
obscuration overnight, but kept VSBY at VFR. KPIH and KIDA will also
have potential, but expectations remain VFR at this time.
DMH
&&
.FIRE WEATHER...Temperatures will continue to slowly climb through
the rest of the week and at least a 10 to 20 percent chance of
afternoon convection will persist. These chances will be mostly
confined to parts of the Eastern Highlands along the Wyoming
border. These storms are expected to be dry storms with the
potential for convective wind gusts of 30 to 40 mph. By Wednesday
afternoon, parts of the Magic Valley, South Hills, and Central
Mountains will join in on the isolated convection. These will
likely be dry storms once again, though wind gusts with these will
range from 35 to 45 mph with the potential for strong gusts of 50
to 55 mph in the Magic Valley and South Hills. The SPC and GACC
have also highlighted portions of fire weather zones 422, 425,
427, 475, and 476 tomorrow for the isolated dry thunderstorm
chances mentioned above. In the second half of the week, we will
keep around the chance for isolated convection each afternoon.
Otherwise, synoptic wind gusts will be in the 15 to 20 mph range
each day with min RHs ranging from mid teens to mid 20s.
AMM
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Tucson AZ
255 PM MST Tue Jul 16 2024
.SYNOPSIS...Temperatures slightly above normal through the rest
of this week, with typical mid July moisture levels across the
region. This will result in the daily chances for showers and
thunderstorms. The main threats will continue to be strong gusty
outflow winds and heavy rainfall leading to localized flash
flooding.
&&
.DISCUSSION...We started this morning with some weak showers/
thunderstorms across Southeast Arizona, and we will likely finish
the day with more established stronger storms. The storm activity
we saw this morning was associated with a mid-level MCV that
tracked across southern Pima county and eventually moved into NW
Sonora Mexico. Typically in the wake of these types of features,
we see a subsidence field that hinders storm development. In this
case though, it is far enough away where it shouldn`t have too
much impact on Southeast Arizona this afternoon.
There are three things that are around to help thunderstorm
activity/development today. The overall pattern is defined by a
mid-upper high centered over central New Mexico with the flow
around this feature resulting in a weak diffluent area across
Southeast Arizona. A trough moving into the Pacific Northwest will
force this high to align more into a NW-SE orientation, resulting
in an area of weak stretching deformation assisting with the
overall lift. The third thing of note today is a weak vort max in
northern Chihuahua Mexico that will continue to rotate around the
base of the upper high and push into the far SE corner of the
state this evening.
So, with this in mind...our thinking is that we will see
thunderstorms develop NE of Tucson this afternoon (which we are
already watching develop via radar). The latest 16/20Z HRRR has
these storms moving off the higher terrain into the Upper Gila
River valley between 4-6 pm. I would expect these storms to
produce a strong outflow as it moves off the terrain, potentially
impacting Safford. Otherwise, thunderstorms east and southeast of
Tucson will be pulse-type and/or delayed until the late afternoon
and evening as we start to see the impact of the approaching vort
max. I have confidence in the University of Arizona 16/12Z WRF-RR
run since it has been resolving the timing/location of convection
very well the past few days. This run delays the majority of the
activity well into the evening hours. Tucson will likely stay on
the northern periphery of the majority of storm activity, just
clipping the Tucson Metro Area late (between 8-10 pm MST) this
evening.
Drier air in the mid-levels of the storm residing in NM and will
push west and entrain into the thunderstorms along the Arizona/New
Mexico border. The 16/12Z HREF is suggesting a 50-70 percent
likelihood of wind gusts in excess of 30+ kts from storms east of
Tucson today. It should be noted that 16/00Z HREF run had a 10
percent chance of wind gusts in excess of 50 kts but has backed
off on this run. The 16/12Z HREF is also pinpointing the heaviest
rainfall to occur S and SE of Tucson in Cochise and Santa Cruz
counties this afternoon/evening with a 10-30 percent chance of
3-hr rainfall amounts in excess of 1 inch, and even a 10 percent
chance of rainfall in excess of 3 inches along the International
Border.
In general, the main threat from storms today will be strong and
gusty thunderstorm outflows, but heavy rainfall is also in the
mix...especially S and SE of Tucson in Cochise and Santa Cruz
county where there is a better mix of moisture and will be
impacted by the weak vort max later this evening.
Otherwise, we will see a continued chance of mainly afternoon and
evening thunderstorms persist into early next week. The upper high
center will slowly drift into NW Arizona by late this week, then
near southern Nevada by the weekend. This puts us in into a more
favorable pattern for strong storms as the flow will move off the
Mogollon Rim/higher terrain into SE AZ. However, resolving which
day that will be more active at this juncture is difficult.
&&
.AVIATION...Valid through 18/00Z.
SCT-BKN clouds at 8k-12k ft AGL thru 17/05Z and again aft 17/18Z,
with diminishing cloud cover between 17/05Z and 17/18Z. SCT
TSRA/SHRA thru 17/05Z, mainly east through south of KTUS and in the
White Mountains. SCT TSRA/SHRA developing again aft 17/19Z. MVFR
conditions in TSRA, with mountain obscurations, vsby reductions and
wind gusts to 40+ knots. Outside of TSRA, SFC wind at most locations
12 knots or less favoring a WLY/NWLY direction during the afternoon
and early evening hours and variable in direction at other times.
The exception will be in the upper Gila River valley near KSAD where
WLY/NWLY SFC wind will be 16-22 kts with gusts to 32 kts thru
17/04Z. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Deeper moisture remains across southeast Arizona,
with typical mid July moisture levels expected through at least the
upcoming weekend. This will result in the daily cycle of mainly
afternoon and evening showers and thunderstorms. The main threats
will be strong, gusty and erratic outflow winds and heavy rainfall
leading to localized flash flooding. Minimum relative humidity
values will be 20-30 percent in most lower elevation locations and
25-40 percent in mountain areas. Away from thunderstorms, 20-foot
winds will generally be 15 mph or less, with afternoon/early evening
gusts to 20-25 mph and light winds overnight. Wind direction during
the afternoon will primarily be west to northwest into the weekend.
The exception will be in the upper Gila River valley around Safford,
where afternoon/early evening winds will be west-northwest around 20
mph and gusts to 30-35 mph through this evening.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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