Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/01/23
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
931 PM EDT Mon Jul 31 2023
.SYNOPSIS...
A weak boundary crosses the region through this evening allowing
for scattered showers and storms to develop. High pressure
builds in Tuesday into Wednesday with below normal temperatures
continuing through the week. Unsettled weather returns by late
week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
As of 930 PM EDT Monday...
A weak cold front extends from the northern Delmarva to central
VA this evening. Showers/tstms in advance of the front have
diminished in coverage this evening, and should continue to
dissipate late this evening. Otherwise, pleasant this evening
with temperatures in the upper 60s to lower 70s. The front will
be slow to cross the area tonight, and some isolated showers may
redevelop over SE VA/NE NC later tonight and into early Tuesday
morning as some moisture pools along the boundary. Lows tonight
rang from the upper 50s NW to near 70F along the coast, with
most areas in the lower to mid 60s.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
As of 245 PM EDT Monday...
Models are still showing a weak, secondary shortwave pushing
through Tuesday, but models remain in general disagreement as to
whether or not there will be convection. 12z HRRR remained the
most aggressive showing widespread scattered showers/storms
whereas the NAM 3KM and WRF members only have limited
showers/storms near the Albemarle Sound. As such, Tuesday
remains a somewhat low confidence forecast for a few isolated to
scattered showers/storms across SE portions of the FA with
moderate confidence in scattered showers/storms across NE NC.
Any convection quickly tapers off after sunset with the loss of
diurnal instability. Highs Tuesday in the mid 80s. A dry cold
front pushes through Tuesday night with high pressure building
in from the N. As such, mostly clear skies will allow temps to
drop into the upper 50s to around 60F in the Piedmont and low-
mid 60s elsewhere except upper 60s to around 70F along the
coast.
Mostly sunny early with partly cloudy skies during the
afternoon Wednesday with high pressure overhead and highs in
the lower 80s NE to mid 80s SE. High pressure moves offshore Wed
night with winds becoming S and lows in the mid 60s for most
(around 70F along the coast). Rain and storm chances increase
again Thursday afternoon as high pressure shifts offshore and we
begin to see more of a return flow across the region.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 245 PM EDT Monday...
A longwave trough remains over the area through Friday with
below normal temps expected. The trough breaks down by Saturday
with zonal flow returning and a ridge developing Sunday into
early next week. A series of shortwaves will bring unsettled
weather through the extended period (mainly in the afternoon and
evening). The best chance for showers/storms will be Friday with
slightly lesser chances each day. Highs in the lower 80s W to
mid 80s E Fri, mid to upper 80s Sat, and upper 80s to around
90F Sun and Mon. Lows in the mid- upper 60s Thurs night and
upper 60s to lower 70s Fri through Sun nights.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
As of 755 PM EDT Monday...
A weak cold front is pushing into northern VA as of 00z.
Scattered showers and a few embedded tstms are currently over
far SE VA and NE NC (to the S of ORF and W/NW of ECG), with
isolated showers/tstms farther N. VFR outside of showers/tstms
with a SE wind of 5-10kt. Showers may bring brief MVFR vsby at
ECG through 03z. Otherwise, primarily VFR with SCT mid level
clouds and a very light and variable wind tonight. However,
some moisture does pool ahead of the approaching cold front and
a few showers could develop over SE VA/NE NC late tonight into
early Tuesday morning, especially near the coast. By Tuesday
afternoon, there is a 30-40% chc of showers/tstms at ORF and
ECG, with 15-20% elsewhere. VFR Tuesday outside of
showers/tstms with a NE/ENE wind of 5-10kt.
High pressure builds in through mid-week. Primarily VFR with a
diminishing chc of convection. High pressure moves offshore
later in the week with a chc of aftn/early evening
showers/tstms.
&&
.MARINE...
As of 355 PM EDT Monday...
Late this aftn, sfc high pressure was centered over the Upper
Midwest, with a rather weak pressure gradient over the local
area. Winds were E-S 5-15 kt over the waters, with waves 1-2 ft
and seas 2-3 ft. A weak trough/front will drop into and across
the waters this evening into early Tue morning. This feature
will also bring a chc of showers/tstms through this evening.
A few of the storms could produce 34+ kt winds, which would
necessitate SMWs. The sfc high currently over the Upper Midwest
is progged to gradually build toward the area from tonight into
Wed morning, before shifting offshore by Wed night. Winds become
N-NE at ~10 kt or less by early Tue morning (and remain around
10 kt or less on Tue), as the high becomes centered over the
ern Great Lakes and weak CAA commences over the waters. There
may be a bit of an uptick in N-NE winds late Tue night over the
srn waters (to 12-15 kt), but still not expecting SCA conditions.
Winds turn to the SE then S from Wed night through Thu (and are
forecast to remain below SCA thresholds), as the high pushes
offshore.
Seas are expected to remain 2-3 ft into Tue night, but may build
to 3-4 ft S of Cape Charles by early Wed morning with the slight
increase in N-NE winds. A Low Rip Current Risk is expected for
Tue, with a Low Rip Current Risk N and a Moderate Rip Current
Risk S for Wed.
&&
.TIDES/COASTAL FLOODING...
As of 355 PM EDT Monday...
Water levels may approach minor flood thresholds this evening
into early Tue morning during the late evening high tide cycle
on the bayside of the MD Ern Shore (mainly in/near Bishop`s
Head, MD) and near Oyster, VA (on the Atlc coast of the VA Ern
Shore). This is mainly due to increasing astronomical tides. As
a result, have issued Coastal Flood Statements for these two
areas (Dorchester county MD and Northampton county VA).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...AJB/RMM
NEAR TERM...AJB/AJZ
SHORT TERM...AJB
LONG TERM...AJB/RMM
AVIATION...AJZ
MARINE...ERI/TMG
TIDES/COASTAL FLOODING...AKQ
AREA FORECAST DISCUSSION
National Weather Service Albany NY
946 PM EDT Mon Jul 31 2023
.SYNOPSIS...
Isolated showers and thunderstorms will end early this
evening, as a cold front moves through the area. High pressure will
ridge in overnight and be in control through the mid week with
comfortable humidity levels and slightly below normal temperatures.
Some clouds will increase on Thursday with a chance of a shower or
thunderstorm late in the day west of the Hudson River Valley.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE...As of band of mid level clouds extends from southern
VT into the northern portions of the Capital Region and Mohawk
Valley. Still a few sprinkles across portions of southern VT and
northern Berkshires. This band seems to be located within close
proximity to the reinforcing cold front, with a light
north/northeast wind to the north of this band, and a more
west/northwest breeze to the south.
This band should continue settling slowly south over the next
few hours. With clear skies across the southern Adirondacks,
temps have already dropped into the upper 40s/lower 50s, while
temps remain elevated farther south/east, especially where
clouds persist, with lower/mid 60s.
Temps may hold relatively steady where clouds persist over the
next few hours, before falling off after midnight. Still expect
min temps to drop into the lower/mid 50s for most areas, and 40s
across the southern Adirondacks, with perhaps some lower 40s
possible across portions of northern Herkimer/Hamilton Counties.
Patchy river valley fog will be possible, especially where any
showers occurred previously.
[PREVIOUS 354 PM EDT]...A weak cold front and a short-wave
rotating around the mid and upper level trough continues to move
across southern NY and southern New England this afternoon.
SPC RAP Mesoanalysis depicts PWATs generally an inch or less with
dewpoints in the 50s. Mid level lapse rates are around
6 C/km. ML CAPE values are in the 200-500 J/kg range. O-6 km
effective shear values are 20-30 KT. Some low topped convective
cells are possible with small hail /half inch or less/ with
gusty winds 30-40 mph, but severe weather is not expected with
limited instability. The showers and thunderstorms will
decrease quickly with the loss of the diurnal heating.
The skies will gradually clear from northwest to southeast
overnight with some patchy fog developing in the valleys. Weak
cold air advection will be ongoing. Lows will fall into mid 40s
to around 50F north of the Capital District and lower to mid 50s
to the south and east. High pressure will be building in from
the west to northwest toward daybreak.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Tomorrow...A pleasant day is expected with the sfc anticyclone
building in from the Great Lakes Region. The strong subsidence
will yield partly to mostly sunny skies and with H850 temps a
little below normal, expect max temps run below normal by close
to 10 degrees. Highs will be in the lower to mid 70s in the
valley areas with a few upper 70s in the mid Hudson Valley. 60s
to around 70F will be common over the higher terrain.
An ideal radiational cooling night is expected Tue night with
the sfc anticyclone building in over NY and New England with clear
skies and light to calm winds. Lows will fall into the 40s to
lower 50s. Isolated upper 30s are possible in the southern
Adirondacks. Some patchy radiational fog is possible in the
major river valleys.
Wednesday will be another splendid day with abundant sunshine
and comfortable humidity levels. Sfc dewpoints will be in the
40s to 50s. Temps will still be below normal, but a little
warmer than Tue. Highs will be in the mid and upper 70s in the
valleys and over the hills, and mid 60s to lower 70s over the
mtns. Another cool and pleasant night is expected Wed night with
the sfc high slowly shifting east of New England. Lows will be
in the mid 40s to lower 50s over the higher terrain and 50s in
the valleys.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
The extended forecast opens with the sfc high moving further
downstream, as a warm front moves north of the region. An
isolated or late day shower or thunderstorm is possible west of
the Hudson River Valley. Temps moderate closer to normal for
early August. A cold front and a prefrontal trough bring some
showers and isolated to scattered thunderstorms Thu night
through Friday. PWATs briefly rise above normal with numerous
showers possible with likely PoPs Fri afternoon. Mins will be
milder Thu night with mid 50s to mid 60s. Highs will be
surpressed due to cloud cover on Friday with 70s and some upper
60s over the higher terrain. The medium range guidance has the
front moving trough quicker Fri night, the weekend could end up
drier.
High pressure ridges in south of James Bay with cooler and drier
air returning. There is some uncertainty with the medium range
guidance that the front stalls near the coast with a slight or
low chance of showers south and east of the Capital Region on
Saturday. Sfc ridging builds in Sunday with max temps near
normal. A low pressure system moves towards the Great Lakes
Region approaches on Monday, as it warm front may bring some
scattered showers and thunderstorms to open next week. Temps
will continue to be near normal for early August with 70s to
lower 80s.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Through 00z/Wed...Any lingering isolated showers will end early this
evening, then high pressure will bring dry weather overnight and
through the day Tuesday. VFR conditions are expected for the
upcoming TAF period with the exception of possible fog development
tonight, mainly at KGFL/KPSF, though the duration and thickness of
fog is uncertain. Will MAINTAIN the MVFR vsbys from the previous TAF
issuance at this time.
North to northwest wind at 5-10 kt early this evening will become
light to calm overnight. Wind will then be out of the north to
northwest again on Tuesday at 6-12 kt.
Outlook...
Tuesday Night: No Operational Impact. Patchy FG.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Low Operational Impact. Slight Chance of SHRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday: High Operational Impact. Likely SHRA...TSRA.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Low Operational Impact. Slight Chance of SHRA.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Wasula
NEAR TERM...KL/Wasula
SHORT TERM...Wasula
LONG TERM...Wasula
AVIATION...Rathbun
Forecast discernment then becomes maximum daytime temperatures from
midweek into the weekend. Long, extended warm tail on box and
whisker blots have the GFS/fv3 to thank, lying between the 75th to
90th percentile. Have continued with National Blend, but again,
something to keep an eye on with better agreement in coming
forecasts. Temperature disagreement continues into the weekend, with
a 10 degree spread in the NBM IQR at this time. Dependent on timing
of potential surface cold front that wraps up this week.
Weekend Storm Chances:
Precipitation and storm chances return Friday night through the
weekend as aforementioned cold front sags through and significant
shift in the synoptic pattern expected. Ensemble (EPS 31.12Z;
GEFS 31.12Z) models both exhibit low confidence for location,
magnitude, and depth of flattening ridge. Deterministic (GFS
31.12Z; ECMWF 31.12Z) guidance agree on a surface low scooting
east across the Central Plains becoming well wrapped up and
deepening along a phasing trough and upper level jet streak. Will
be something to keep an eye on for specifics with diurnal timing
and location of best quasigeostrophic ascent. Both ensembles paint
better chances through the Central to Northern Plains for any
instability.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1040 PM CDT Mon Jul 31 2023
A combination of a deep layer of light winds (up to 700 mb) and
clear skies will result in some valley fog developing again
tonight. The one negative is that moisture is rather shallow in
the NAM and the RAP, HRRR, and GFS do not saturate the boundary
layer. Due to this, stayed with BCFG for KLSE.
With many of the CAMs keeping the showers and thunderstorms out of
the TAF sites for Tuesday evening, kept them dry and stayed with a
mainly high ceiling.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...JAR/Zapotocny
AVIATION...Boyne
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
1027 PM CDT Mon Jul 31 2023
.UPDATE...
Issued at 1027 PM CDT Mon Jul 31 2023
The threat across the Severe Thunderstorm Watch appears to be
winding down, and the watch will be allowed to expire on time.
Meanwhile, a thunderstorm in Bowman County recently became severe
and produced ping pong ball size hail. Current radar trends suggest
the strongest storms are likely to remain south of the ND/SD border,
but there is still around 50 kts of effective bulk shear if any
storm can take full advantage of MUCAPE approaching 3000 J/kg.
UPDATE Issued at 714 PM CDT Mon Jul 31 2023
At 7 PM CDT, a classic supercell was slowly propagating south
through central Bottineau County. The immediate downstream
environment remains favorable for supercell maintenance, and the
most recently initialized HRRR did assimilate the supercell and
maintains it as far south as Wells County through 10 PM CDT. Other
attempts at sustained updrafts have been made over northern Sheridan
and southern McHenry Counties over the past 1-2 hours, but have yet
to be fully successful. The 00 UTC Bismarck RAOB does show weak
capping at both 700 mb and above 500 mb, and smoke aloft arriving
from the west could also soon be a prohibiting factor for severe
convection along and south of Highway 200.
The Storm Prediction Center has issued a Severe Thunderstorm Watch
for areas west of the Devils Lake Basin into the northern James
River Valley, in effect until 11 PM CDT.
&&
.SHORT TERM...(This Evening through Tuesday night)
Issued at 248 PM CDT Mon Jul 31 2023
An isolated severe thunderstorm threat is possible today, but
occurrence of thunderstorms in general is uncertain. Chances for
severe thunderstorms will be higher tomorrow afternoon and
evening.
In the upper levels, a ridge was centered over central-eastern
Montana and Wyoming, while a vort max was evident on water vapor
imagery rounding the ridge axis and moving over the northern to
eastern portions of the state. While the ascent associated with
the vort max has moved off to the east, the southwest flow over
the Northern Rockies upstream of the ridge axis has developed weak
pressure falls and a surface low over eastern Montana and western
North Dakota. A southerly fetch of moisture in the warm sector of
this low has brought surface dew points into the 60s, with a few
lower 70s, across western and central North Dakota (though less so
along far western North Dakota). As temperatures climb into the
80s today, MLCAPE reaching 2000 J/kg combined with 40-50 kts of
effective shear to produce a conditional severe threat day. The
fly in the ointment will be the lack of obvious synoptic or
mesoscale forcing, outside of weak convergence near the Montana
border and into southeast Saskatchewan. As of 1930Z, visible
satellite imagery did show signs of the moisture convergence in
northwest to north central North Dakota, which may signal an area
of relatively greater probability of initiation. If thunderstorms
do develop, the strong shear and CAPE combination should allow for
a severe hail and wind threat. But again this remains highly
conditional. Due to the uncertainty in sustained updrafts,
messaging was kept to the isolated potential for golf ball size
hail and 60 mph wind gusts.
On Tuesday, another speed/vort max rounds the ridge axis, this
time arriving during the day with a relatively stronger associated
front. A stronger surface low should draw dew points further into
the upper 60s to lower 70s, combining with steep mid-level lapse
rates and 30-40 kts of effective shear for a potential supercell
environment. With stronger surface based convergence along the
front, thunderstorms should develop along and near this front
across northern North Dakota in the afternoon and then into
southern North Dakota in the evening as the front and surface low
drop south. Isolated thunderstorms may be possible further ahead
of the front towards southern North Dakota in the afternoon, but
confidence in this is lower. With the CAPE/shear parameter space
and stronger confidence in forcing mechanisms, two inch hail and
70 mph wind gusts will be messaged. The storm mode transitions
will likely cause these hazards to evolve however, as mean wind
and bulk shear vectors are oriented zonally along the west-east
oriented front. Initially discrete cells should pose the strongest
hail threat while eventual cell clustering could lower the hail
threat ceiling a bit. Convection may continue into the late night
along the path of the southward dropping mid-level wave, but
coverage should be greatest in the evening.
As the ridge axis will become centered over the state on Tuesday,
hot temperatures are expected with highs in the upper 80s and
lower 90s. Lows will be quite mild in the morning with Tuesday
morning temperatures only falling into the 60s.
.LONG TERM...(Wednesday through Monday)
Issued at 248 PM CDT Mon Jul 31 2023
Chances for showers and thunderstorms become more widespread
Thursday and Friday, while seasonably cool temperatures are
expected Friday through the weekend.
Any impact of temperatures by Tuesday`s front will be short lived
as the ridge is expected to build again Wednesday, with highs
again in the upper 80s and lower 90s. Precipitation chances look
very low with the building ridge. Thursday and Friday the ridge
flattens and begins to break down as a series of northern stream
fronts push into the region. Additionally, deterministic guidance
depicts a weak meandering low moving into the region from the
southwest through Friday, which brings widespread chances for
showers and thunderstorms starting later Thursday through Friday.
Greater chances currently look to be in southern portions of the
state but there are at least low chances across the entirety of
the state. Probabilities for CAPE look low enough that severe
convection is unlikely in this Thursday-Friday period. From
Friday onward, a transition to northwest flow is likely based on
the suite of ensembles, which brings seasonably cool temperatures.
Daily highs through the weekend range from the upper 70s to the
lower 80s while lows drop into the 50s. Precipitation chances also
fall off in the northwest flow, though isolated diurnal
convection each afternoon will be possible.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 714 PM CDT Mon Jul 31 2023
Isolated thunderstorms across central North Dakota this evening are
not likely to impact any terminals. VFR conditions are likely
through the forecast period. More widespread showers and
thunderstorms could develop across northern North Dakota Tuesday
afternoon, but confidence in timing and coverage is not yet high
enough to include a mention in the TAFs.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Hollan
SHORT TERM...AE
LONG TERM...AE
AVIATION...Hollan
Area Forecast Discussion
National Weather Service State College PA
1059 PM EDT Mon Jul 31 2023
.SYNOPSIS...
Pleasant and mainly dry weather is expected through midweek. A
spotty shower or isolated thunderstorm cannot be ruled out today
or Tuesday, but the majority of the time will be dry. More humid
conditions later this week will increase the odds for showers
and thunderstorms from Thursday into the first weekend of August.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Radar loop at 03Z shows just a lone shower left southeast of
KIPT associated with a weak cold front. Waning forcing behind
the parent shortwave and a cooling/stabilizing boundary layer
should cause the remaining shower to fall apart by around
midnight with mainly clear skies anticipated the rest of the
night.
The Nighttime Microphysics Channel is already indicating valley
fog across the northern tier of the state, where rain fell
earlier this evening. Mostly clear skies, dry air and a light
wind should support efficient radiational cooling overnight with
lows 3-6F below average for late July. Much warmer river/stream
waters, combined with the nearly calm wind, should promote
patchy fog in the deep valleys of the Alleghenies and near any
bodies of water. Satellite imagery shows an impressive plume of
smoke aloft approaching from the Grt Lks. This should begin to
overspread the southwest part of the forecast area late tonight.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
Upper level troughing will remain over the region Tuesday,
resulting in another cool day for mid summer. Diurnal heating,
combined with the cool temps aloft, could possibly support an isolated
shower or two. However, odds appear below 10pct, so no mention
in the grids. The latest HRRR indicates the thick plume of upper
level smoke will affect the southwest part of the forecast area
Tuesday, so have increased cloud cover grids over that area.
Mixing down model 850mb temps of 10-12C supports highs mainly in
the 70s, but near 80F over the Lower Susq Valley. However, may
need to trim max temps over the southern tier if smoke is as
thick as the HRRR suggests. An examination of forecast soundings
shows dry air above a weak inversion Tuesday afternoon,
supporting blending the lower MAV dewpoints with the NBM.
Clear skies, a calm wind and dry air under the arriving surface high
should result in optimal radiational cooling Tuesday night. The
result will most likely be the coolest night across Central PA
since early June. Have blended the cooler MAV guidance with the
NBM, resulting in expected lows ranging from the low 40s in the
coolest valleys of the north, to the low and mid 50s over the
Lower Susq Valley. Warm river/stream waters, combined with the
cool temps and a calm wind, should once again lead to late
night fog in the deeper valleys of the Alleghenies and near any
larger bodies of water.
There appears to be a near 0% chance of rain Wednesday into
early Thursday, as surface high pressure and low-pwat air migrates
across the state to the Mid Atlantic coast. A digging upstream
trough and passage of the surface high off of the east coast
will result in warmer and slightly more humid conditions with an
increasing chance of showers Thursday PM. However, a northwest
flow aloft will limit the moisture return and the chance of
showers. Latest guidance indicates the best chance of late
day/evening convection will be over southeast PA, where progged return
flow moisture is a bit better.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
All medium range guidance tracks the upper trough and associated
cold front through Central PA Friday, accompanied by scattered
showers/tsra. Progged pwats are unimpressive in northwest flow
pattern, so NBM POPs in the 30-40pct range appear reasonable.
Ensemble mean qpf indicates most likely areal average rainfall
with the fropa will be <0.10 inches.
The latest GEFS and ECENS both support a return to fair and
seasonable weather next weekend, as the cold front passes well
south of PA and high pressure builds in from the Grt Lks. The
chance of showers returns Sunday PM associated with a returning
warm front lifting in from the Ohio Valley. However, the best
chance of rain/storms may be Monday PM associated with a cold
front passage. A deep southwest flow preceding this front will
advect a seasonably moist air mass into the region ahead of the
front, supporting a good chance of convection. Latest ensemble
plumes suggest areal average rainfall between 0.25 and 0.50
inches is likely Sunday night/Monday, with locally higher
amounts under any stronger storms.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
A few showers will remain possible across the northern tier
(BFD, IPT) this evening. After sunset, expect showers to quickly
decrease in coverage and winds to go calm. Combined with mostly
clear skies, this will likely again lead to valley fog late
tonight into early Tuesday morning, mainly across the N and W
mtns. Fair weather is expected Tuesday with VFR conditions and a
stray afternoon shower possible once again.
Outlook...
Wed...No sig wx expected.
Thu...Restrictions possible in PM rainfall.
Fri...Restrictions will be possible in showers and
thunderstorms.
&&
.CLIMATE...
Top 5 Wettest July | Williamsport, PA
1. 2018 11.99"
2. 2023 10.05" (1 day left)
3. 1992 9.65"
4. 1958 8.30"
5. 1928 8.02"
July 2023 was the 7th wettest July on record in State College,
with 6.36" of rain observed. The record was 9.37" in Jul 2018.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...DeVoir
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Fitzgerald
AVIATION...Banghoff/Bauco
CLIMATE...
Area Forecast Discussion
National Weather Service Dodge City KS
647 PM CDT Mon Jul 31 2023
...Updated Aviation Section...
.SHORT TERM...(This evening through Tuesday night)
Issued at 1237 PM CDT Mon Jul 31 2023
Short term forecast remains largely on track compared to this time
yesterday, as midday water vapor satellite imagery and RAP upper
air analysis confirm the subtropical ridge is centered over the
southern plains with longwave troughing east of the Mississippi
River. As the ridge slowly meanders southeast through today,
strong subsidence will support 850-mb temperatures increasing into
the upper 20s/low 30s Celsius, which will translate to a miserably
hot afternoon with highs in the low 100s. To make matters worse,
dewpoint temperatures in the low to mid 60s will foster heat
indices peaking in the 105-108 range, triggering the westward
expansion of a Heat Advisory to encompass all counties along and
east of US-283 except Ford and Clark counties that will be in
effect until 02Z Tuesday. Overnight, CAMs/HREF guidance all agree
convective activity will fail to reach southwest KS, resulting in
a dry and quiet forecast with lows in the low/mid 70s.
Daytime Tuesday, the upper level subtropical ridge will continue
its trek south/southeastward while weakening as a longwave trough
off the west coast sends a series of shortwave impulses northeast
through the Desert Southwest and into the central Rockies/central
plains. The majority of southwest KS will still be firmly under
the influence of the ridge, allowing afternoon highs in the low
100s to persist across roughly the southeastern 2/3rds of our
area. However, weak height falls across the northwest zones will
shave a few degrees off afternoon temperatures, with highs in the
upper 90s. Dewpoint temperatures will once again hold in the low
to mid 60s across the area, resulting in another Heat Advisory
that currently only includes counties along and east of US-183,
but a westward expansion of this advisory is planned to include
Ness, Hodgeman, Ford, Clark, Gray, and Meade counties.
As the upper level subtropical ridge breaks down Tuesday evening
into the overnight period, increasing westerly flow aloft should
allow for a non-zero chance of thunderstorms. This scenario is
supported by latest CAM guidance which indicates a loosely
organized convective complex emerging from eastern CO and
potentially entering the northwest/north zones around or shortly
after sunset. Weak CAPE/shear will likely limit severe potential,
although the strongest storms could contain small hail and gusty
winds along with frequent lightning and heavy rainfall. Any
thunderstorms that do reach southwest KS will be long gone by
sunrise, and lows will drop into the low/mid 70s once again.
.LONG TERM...(Wednesday through Monday)
Issued at 146 PM CDT Mon Jul 31 2023
Key Messages: one final day of excessive heat on Wednesday before
cooling trend begins Thursday through the end of the period.
Precipitation chances also return, especially Saturday and Sunday
evenings.
Medium range ensembles are in agreement regarding the upper level
pattern at the beginning of the long term period, suggesting the
upper level subtropical ridge will be centered over the central
plains with weak troughing over the Pacific Northwest and the
Upper Midwest/northeast CONUS. The expected breakdown/retrograding
of the ridge will continue during the day Wednesday, but still
bring one final day of unpleasant heat for the lion-share of our
area, with at least the southeast half of southwest KS
experiencing afternoon highs in the upper 90s/low 100s while
everyone else sees low/mid 90s. Thankfully, a cooling trend
should commence Thursday as the subtropical ridge continues to
weaken/retrograde, allowing afternoon highs to drop steadily
through the end of the period from the mid/upper 90s Thursday all
the way down to the low/mid 80s on Monday.
In addition to the cooler temperatures, precipitation chances will
increase Thursday and beyond as stronger westerly flow aloft
helps shortwave disturbances promote synoptic-scale lift over the
central plains. This is supported by a strong signal within the
ensemble meteograms of widespread precipitation, likely in the
form of thunderstorms moving into our area from eastern CO. Best
chance appears to surround Saturday and Sunday evenings, as NBM
PoPs are inching into the likely category (55-74%) both nights.
Ensemble mean of precipitation totals suggest the northern zones
will be favored to receive the most precipitation, with both the
GEFS and EPS showing 1"+ of QPF by the end of the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 645 PM CDT Mon Jul 31 2023
Quiet and dry weather will continue through this TAF period ending
early Tuesday evening. Prevailing wind out of the south will
continue, with the exception of HYS where a very slow-moving cold
front was just pushing through HYS at the onset of this new TAF
period. Winds at HYS will be east-northeast through much of the
night. Wind speeds at all terminals will be 8 knots or less much
of the overnight through early Tuesday morning with widespread VFR
flight category.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 74 102 72 98 / 0 10 20 10
GCK 72 99 70 95 / 0 10 20 10
EHA 72 98 68 96 / 0 10 30 10
LBL 74 101 71 98 / 0 10 10 10
HYS 74 99 72 95 / 10 10 30 10
P28 76 103 77 103 / 0 0 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM CDT this evening for KSZ030-031-045-046-
064>066-079>081-089-090.
Heat Advisory from noon to 9 PM CDT Tuesday for KSZ031-045-046-
064>066-077>080-087>089.
Excessive Heat Warning from noon to 9 PM CDT Tuesday for KSZ081-
090.
&&
$$
SHORT TERM...Springer
LONG TERM...Springer
AVIATION...Umscheid
Area Forecast Discussion
National Weather Service Duluth MN
659 PM CDT Mon Jul 31 2023
.DISCUSSION...(This evening through Sunday)
Issued at 459 PM CDT Mon Jul 31 2023
Summary: Smoke will linger over parts of the region through
Tuesday afternoon with increasing chances for showers and
thunderstorms Tuesday through Thursday. Temperatures warm above
normal into Thursday before cooling to more seasonal levels into
the weekend behind a cold front.
High pressure remained in control across the region this afternoon
with a warm front located just to our east across central Lake
Superior. Smoke aloft was evident on satellite across much of the
Northland with thicker smoke along and north of the International
Border. Some of this smoke was mixing closer to the surface with
KCKC reporting visibility of 5 miles due to smoke. Any remaining
diurnal cu will diminish this evening leaving mainly clear skies
overnight aside from the smoke.
Heading into Tuesday morning, a jet streak moves overhead along
with a weak shortwave. CAMs present multiple solutions in this
weakly forced environment ranging from an MCS dropping southeast
out of Manitoba across northern Minnesota per the HRRR with the
NAMNEST developing storms over northwestern Minnesota downstream
of an cluster of storms in the eastern Dakotas with little to no
convection per the various WRF flavors. This convection evolution
remains below confidence, but forecast soundings show a capped
environment through much of the day. A cold front will sag
southward out of Manitoba into North Dakota Tuesday evening into a
very moist and unstable airmass. With bulk shear around 30 knots,
this would support the threat of supercells early on with large
hail congealing into clusters Tuesday night with more of a wind
threat as they move into northern Minnesota. This activity may
reach out western zones overnight and still may be strong to
severe roughly west of an IFalls to Brainerd line.
Models continue to disagree with where the cold front will end up
for Wednesday, but it will be somewhere across the Northland. The
most likely scenario is that it will bisect the region from
northeast to southwest from Lake Superior into the Brainerd Lakes
area. While some showers and storms will be possible behind the
front, the best chances will be ahead of the front across the I-35
corridor into northwest Wisconsin. Shear will still be around 30
knots, so supercells with large hail will be possible early on
before upscale growth later in the evening and a transition to
more of a wind threat. The front may linger over the region into
Thursday with another round of showers and storms possible. Models
further diverge heading into the weekend, but it does appear that
rain chances will persist as a system moves through the Upper
Midwest.
Temperatures will remain on the warm side of normal into Thursday
with highs in the 80s for most Wednesday and Thursday. Confidence
on highs for Thursday is lower, however, with the front possibly
stalling out across the region. Cooler air is expected to filter
in behind the front for the weekend with a return to more seasonal
temperatures in the 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 657 PM CDT Mon Jul 31 2023
Smoke aloft continues across the region this evening, with
afternoon VFR cumulus gradually burning off. Expect VFR through
the period as most of the smoke remains aloft, though some near
surface smoke may impact the INL area into the Arrowhead for this
evening and tonight and bring VFR to possibly MVFR visibilities.
Patchy fog remains possible late tonight, primarily at HIB and
HYR. Otherwise, high pressure remains in control bringing light
winds and dry conditions through tonight.
Several models do indicate the potential for scattered
showers/storms over north-central into central Minnesota tomorrow
afternoon into early evening, but confidence in the placement and
coverage of storms is too low at this point to include any
prevailing shower or storms in the TAFs with this update.
&&
.MARINE...
Issued at 459 PM CDT Mon Jul 31 2023
Minimal concerns regarding winds and waves are expected over the
next 48 hours. Chances for thunderstorms will return Tuesday night
and into Wednesday. A few strong to severe storms cannot be ruled
out later Wednesday. Winds will remain around 5 to 15 knots
through the period, but a few gusts to 20 knots will be possible
on Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 55 79 59 84 / 0 10 20 20
INL 54 83 59 84 / 0 40 40 20
BRD 58 86 64 89 / 10 20 20 20
HYR 54 84 61 85 / 0 10 20 20
ASX 56 83 61 85 / 0 10 30 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
DISCUSSION...BJH
AVIATION...Rothstein
MARINE...BJH
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
559 PM MDT Mon Jul 31 2023
...New AVIATION...
.SYNOPSIS...
Issued at 215 PM MDT Mon Jul 31 2023
Scattered mountain and isolated lowland storms will be possible
much of the period with the highest chances for storms this
afternoon and tomorrow. Chances gradually decrease after that.
Highs will also gradually climb each afternoon.
&&
.DISCUSSION...
Issued at 215 PM MDT Mon Jul 31 2023
We have a monsoonal pattern, but it`s not turning out too robust.
The UL high that has plagued us with heat is centered over far SW
OK, but it remains rather large. Additionally, we have a subtle
inverted trough nearing the International Border as of 2PM.
Moisture is a bit lacking but sufficient at about 1 inch PW. The
main thing is the lack of heating from earlier cloud coverage and
light showers is hurting instability. So far, shower and
thunderstorm activity is mainly limited to mountains. We will
retain shower and thunderstorm chances through the rest of the
afternoon and into the overnight hours and even to a lesser degree
the morning. Then, tomorrow, moisture will remain similar but
with a couple / few degrees of warming. We will have a bit more of
an influence from the ridge as it begins to nose back west plus
we will not have the inverted trough. The net result will be
another day of scattered mountain storms with isolated storms
possible in the lowlands. Interestingly enough, the 18z HRRR
shows us more active tomorrow than today, which makes sense from
the increase in heat.
We repeat this pattern again Wednesday but with a bit of a
decrease in moisture and subsequent storm chances/ coverage.
Temperatures will also rise a couple more degrees. The high will
be slow to expand and shift west as we progress through the week.
This will cause a continual but gradual decline in moisture and
precip chances and an increase in our temperatures. By this
weekend, the high will basically be overhead, which will bring us
our hottest temperatures and lowest precip chances. Storm coverage
will be largely limited to the mountains although the GFS is a
bit more aggressive in bringing a few storms into the lowlands.
Either way, our best three days to get any rain in the lowlands is
today through Wednesday. After that, we return to the misery that
has been Nonsoon 2023.
53 days until fall.
&&
.AVIATION...
(00Z TAFS)
Issued at 548 PM MDT Mon Jul 31 2023
This morning`s clouds across the Rio Grande valley is, so far,
limiting thunderstorms in that region. East and west of the Rio
Grande, we have isolated to scattered thunderstorms developing. We
will likely see thunderstorms build into the Rio Grande region
later tonight, but the exact timing and location is still a little
up in the air. All thunderstorm activity will die off soon after
midnight, but we will likely see another round of isolated to
scattered thunderstorms again on Tuesday afternoon. The main
threat from the thunderstorms, both today and Tuesday will be the
strong outflow winds. Outside of thunderstorms, we will see off
and on mid and high ceilings of SCT-BKN120-250. Storm motion today
will be from the south to the north.
&&
.FIRE WEATHER...
Issued at 215 PM MDT Mon Jul 31 2023
Moisture has increased for the entire area, which has led to an
uptick in thunderstorms, mainly in the mountains. It also has led
to an improvement in RH recoveries as well as minimum RH values
in the lowlands. Tuesday`s min RH values will be around 20
percent. With the increase in moisture, we will see scattered
storms in the mountains with isolated storms in the lowlands. We
will see a gradual decrease in moisture though along with a
gradual decrease in thunderstorm coverage / chances. Temperatures
will also rise each afternoon. By this weekend, storms will mainly
be limited to mountains. Winds will be fairly light outside of
storms, topping out around 10 MPH.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 77 101 78 103 / 30 20 30 20
Sierra Blanca 68 93 69 93 / 20 50 30 30
Las Cruces 73 101 74 102 / 30 10 30 20
Alamogordo 71 97 71 99 / 20 30 20 30
Cloudcroft 53 73 54 74 / 30 70 30 60
Truth or Consequences 71 97 72 98 / 20 30 20 30
Silver City 64 90 66 91 / 40 30 20 40
Deming 70 99 71 101 / 30 10 20 20
Lordsburg 67 96 69 98 / 40 20 20 30
West El Paso Metro 77 99 77 101 / 30 20 30 20
Dell City 72 98 71 99 / 20 40 20 20
Fort Hancock 73 101 72 103 / 30 40 30 30
Loma Linda 70 92 70 93 / 20 30 30 40
Fabens 73 98 74 100 / 30 20 30 20
Santa Teresa 73 98 74 99 / 30 20 30 20
White Sands HQ 76 98 75 100 / 30 30 30 30
Jornada Range 71 97 71 99 / 30 20 30 20
Hatch 70 99 70 101 / 30 20 20 20
Columbus 72 98 74 100 / 30 20 30 20
Orogrande 71 96 69 97 / 20 30 30 30
Mayhill 59 84 57 85 / 30 70 30 60
Mescalero 57 84 56 85 / 30 70 30 50
Timberon 55 83 55 83 / 20 60 30 60
Winston 60 86 59 86 / 30 50 20 50
Hillsboro 66 96 67 97 / 30 30 20 40
Spaceport 68 97 69 98 / 30 20 20 20
Lake Roberts 57 88 59 90 / 40 40 20 40
Hurley 65 95 65 96 / 40 30 20 30
Cliff 57 98 59 100 / 40 30 20 30
Mule Creek 63 91 66 93 / 50 30 20 30
Faywood 68 94 68 96 / 30 30 20 30
Animas 67 96 70 99 / 40 20 20 30
Hachita 67 96 70 98 / 40 20 20 30
Antelope Wells 66 95 69 98 / 40 30 30 40
Cloverdale 65 91 67 93 / 40 20 20 40
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...None.
&&
$$
FORECASTER...15-Brice
Area Forecast Discussion
National Weather Service Flagstaff AZ
841 PM MST Mon Jul 31 2023
.SYNOPSIS...Monsoon moisture will remain in place over Arizona
with widespread showers and thunderstorms through Tuesday. A
drying trend and warming trend starts Wednesday and will last well
into next week.
&&
.UPDATE...The radar is still showing showers across much of
northern Arizona and a few lingering thunderstorms in Yavapai
County. Although we mostly expect storm activity to diminish
overnight, the U of A 18Z HRRR WRF model run is hinting at
additional activity pushing up from the south later this evening
and into the overnight hours. If this pans out, look for
additional showers and storms in southern Yavapai County and
northern Gila County later this evening.
We are still anticipating another round of showers and storms tomorrow,
but multiple hi-res guidance are leaning towards slightly less
activity than today. As a result, our POPs have been adjusted
downward. Storms that do develop will still be capable of
producing frequent lightning, periods of heavy rain, and strong
outflow winds. Be sure to have a way to receive weather
updates/alerts!
&&
.PREV DISCUSSION /313 PM MST/...High pressure over the Panhandles
has brought a moist southerly flow over northern Arizona with
widespread showers and thunderstorms developing. This activity
will last well into the evening before decreasing overnight.
The high remains in nearly stationary through Tuesday before
starting to slide to the south late Tuesday into Wednesday.
Similar conditions are expected on Tuesday but with the high
settling to the south and becoming more elongated along the
international border, the moist flow will decrease. The flow aloft
will become more southwest to westerly and much drier. Storm
coverage will decrease on Wednesday, becoming even more isolated
by Thursday with the best chances having shifted to mainly just
the White Mountains region. This pattern will prevent much
moisture from moving over Arizona through next week.
Temperatures will remain seasonably cool through Tuesday but we
will start to see temps start to creep back up as we dry out
across the desert southwest. Overnight temperatures over the high
country will also drop with the dry air in place.
&&
.AVIATION...For the 06Z TAF Package...Isolated to scattered showers
and thunderstorms will remain across much of northern Arizona
through 06Z. Strong outflow winds will be possible near storm
development. Otherwise, southwest winds generally less than 10 kts
will prevail. After 18Z, expect additional showers and thunderstorms
to occur across northern Arizona. VFR conditions will continue
through the TAF period, but brief MVFR conditions may be possible in
heavy rain. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Tuesday and Wednesday...Scattered showers and
thunderstorms will continue tonight. Another round of storms is
forecast for Tuesday afternoon with cool temperatures, before a
drying/warming trend sets up on Wednesday.
Thursday through Saturday...A warming and drying trend will last
through the weekend. Southwest to west winds 15-25 MPH each
afternoon with minimum humidity values at or below 15% by Friday.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PUBLIC...Konieczny/MAS
AVIATION...Konieczny
FIRE WEATHER...Konieczny/MAS
For Northern Arizona weather information visit
weather.gov/flagstaff
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
635 PM CDT Mon Jul 31 2023
...Aviation Update...
.UPDATE...
Issued at 518 PM CDT Mon Jul 31 2023
With steady but fairly light easterly (upslope) flow overnight,
temperatures forecast to fall near dewpoint values and a strong
signal for fog development in the HRRR, opted to update the
forecast this afternoon to include to mention of patchy fog
formation overnight. If the HRRR ends up being correct, could see
fairly widespread dense fog towards morning, but would like to
monitor model trends for a few hours before including
significantly reduced visibilities in the forecast.
&&
.DISCUSSION...(This evening through Monday)
Issued at 356 PM CDT Mon Jul 31 2023
Key Messages:
* Outflow from the morning convection and cloud cover has left
the area slightly cooler than expected. However, heat may
continue to be a concern in north central Kansas Tuesday.
* Mostly dry conditions expected tonight - small (less than 20%)
chance of thunderstorms for central Nebraska.
* Chance for strong to severe thunderstorms return again for
Tuesday evening and overnight.
* Cooler and wetter pattern returns for the second half of the
forecast.
Most along and north of I-80 woke up to showers and some
thunderstorms, this convective debris, rain cooler boundary layer
and cloud cover has kept the area slightly cooler than expected.
This does extend down into north central Kansas where we have a
heat advisory. We are not currently (3pm) close to heat advisory
criteria in these counties, but have decided to keep it for the
potential for more sun and heat tomorrow. The baroclinic boundary
is set up along and just north of I-70 and north of that boundary,
moisture is expected to pool, and while not as hot, will feel
quite uncomfortable with the higher moisture. This boundary will
likely lift northward some during the day tomorrow, and will allow
the midnight shift another chance to look at it before deciding
it`s fate tomorrow.
The models and daily weather have been challenging this past
weekend. Each day is impacted by the convection the night before
and the models struggle with that. They overall get the main
waves/disturbances, but the details are at the mesoscale and that
is difficult to resolve, even with the highest resolution
guidance. Thus, feel that with the cloud cover and cooler boundary
layer, that today/this afternoon is not likely to see
thunderstorm activity. I have a dry forecast for most, with only
15-20 percent chance for precipitation late tonight for remnant
convection that may move across northern Nebraska and clip our
central Nebraska counties.
The concern for thunderstorms then shifts to Tuesday night as
activity develops along the High Plains - further south as the
main upper ridge begins to flatten out. This activity may hold
together and have enough support to move eastward into the
forecast area in the late evening and overnight hours. There is
ample MUCAPE (2500-3500 J/kg) depending on what model you want to
look at and shear improves the further east you go. Think this
activity could yield hail to the size of golfballs.
Wednesday looks impacted by Tuesday night`s activity and thus is
steadily getting slightly cooler with each forecast. The main
front looks to push through towards the end of the week, and
temperatures will be cooler and precipitation chances increase as
we move through the weekend and into the start of the next week.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 559 PM CDT Mon Jul 31 2023
BKN MVFR CIGS can be seen on satellite spreading across the local
area from the east. Expect steady easterly flow near 10 KTS
through the period...which should continue to advect moisture
towards the terminals and likely result in IFR CIGS and some MVFR
fog developing late tonight...and sticking around through
01/14-16Z Tuesday. Thereafter...conditions should improve...with
prevailing VFR conditions returning by early afternoon.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...Heat Advisory until 9 PM CDT Tuesday for KSZ005>007-017>019.
&&
$$
UPDATE...Rossi
DISCUSSION...Billings Wright
AVIATION...Rossi
Area Forecast Discussion
National Weather Service Grand Rapids MI
735 PM EDT Mon Jul 31 2023
LATEST UPDATE...
Aviation
.SHORT TERM...(This evening through Tuesday night)
Issued at 212 PM EDT Mon Jul 31 2023
Forecast concerns in the short term are minimal.
High pressure is centered over Wisconsin and Lake Michigan this
afternoon. Weak convergence over the eastern cwa has taken
advantage of low SBCAPE around 300 j/kg and popped a few isolated showers.
What ever showers do occur this afternoon will quickly dissipate
by evening as instability wanes with sunset.
A similar situation will play out again Tuesday. Weak instability
will be present and a few of the CAMs were painting isolated
showers.
Clear skies are expected tonight. However, visible satellite
imagery shows what the RAP smoke model predicted: a large swatch
of high level smoke is just now crossing into western Lower and
stretches northwest into the Northwest Territories. This smoke
will cloud the sky tonight and Tuesday and perhaps Tuesday night.
Temperatures will fall into the lower to mid 50s again tonight
which will be close enough to the dewpoint to create some patchy
fog. Highs Tuesday will be around 80.
.LONG TERM...(Wednesday through Monday)
Issued at 300 PM EDT Mon Jul 31 2023
- A few storms possible Thursday evening
A weakening cold front will drop down from the northwest during
the afternoon and evening. Mean ensemble sfc based instability
values from the various models show a potential for 500 to 1000
J/kg. Mid to upper level lift remains weak and PWAT values are
shown to stay low(under 1.25 inches). Northern zones are forecast
to see the greatest surface based instability. Forecast soundings
in that region show that Theta-E does drops off enough to warrant
a risk for some gusty winds with any storms. We will therefore
forecast the highest POPs up north, but still keep them at chance
levels given the weak forcing and limited moisture.
- Risk showers/storms Saturday night into Sunday
There is still a lot of spread in the models with the timing and
strength of the next storm system headed our way. As a result,
confidence with the precipitation potential is limited. In
general though the models are showing a mid level wave tracking
into a slightly unstable airmass. Ensemble QPF spread is high but
mean QPF values are low, thus POPs will remain low at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 730 PM EDT Mon Jul 31 2023
VFR is expected to continue for this TAF period. Similar
conditions are likely for Tuesday as compared to today, with
scattered afternoon cumulus development and light W/NW winds.
There is some suggestion for slight reductions to visibility with
light fog developing especially from LAN to JXN, but haven`t seen
any indications yet that IFR is a threat.
&&
.MARINE...
Issued at 212 PM EDT Mon Jul 31 2023
Marine forecast issues are minimal through the short term; high
pressure remains camped out over the Great Lakes, resulting in
light winds.
A cold front will drop south across the lake Thursday night and
it`s possible we`ll need a headline then.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
SHORT TERM...04
LONG TERM...MJS
AVIATION...Hoving
MARINE...04
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1001 PM EDT Mon Jul 31 2023
.SYNOPSIS...
Drier high pressure to our north will control our weather into mid
week. A stationary front to our south will move north as a warm
front in the second half of the week bringing a return of showers
and thunderstorms. As the front crosses our area expect a return of
the heat and humidity especially over the weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 10pm EDT Monday: Radar is clear this evening with light and
variable winds. A light shower will be possible over night, but any
activity will be very widely scattered. Overnight lows look to be at
or just below normal, and slightly below last night due to some
decline in dewpoints.
500mb RAP heights show troughing over the eastern US with a large
anticyclone over the Southern Plains. This upper pattern should
remain unchanged through the near term forecast period. At the sfc,
high pressure will slowly migrate eastward across the Great Lakes
region while the southern periphery of the ridge extends into the
western Carolinas. This sfc ridge will lead to a much drier airmass
which will limit convective potential through the period. Highs this
afternoon will be near climo to a few degrees above climo. Lows
tonight will be near climo.
Isolated showers and thunderstorms will be possible again Tuesday
afternoon and early evening, however CAMs are not in great agreement
regarding the coverage/placement of activity. Thus, capped PoPs to
slight chance along the eastern fringe of the CWA as well as along
the Blue Ridge Escarpment. The Day 2 SPC Severe Wx Outlook looks
very similar to today`s with a Marginal risk for severe storms
across the far SE fringe of the CWA. With some instability lingering
on Tuesday, could not rule out an isolated strong to severe storm.
Highs on Tuesday will be a few degrees cooler compared to today and
a few degrees below climo.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 150 PM EDT Monday: The forecast area will be in northwest
flow, between a trough axis off the East Coast and an anticyclone
over TX, through the period. A series of short waves will move
through the flow and across the area. Surface high pressure centered
over the Mid Atlantic at the start of the period will move off shore
allowing a moist southerly flow to develop, especially by Thursday.
The increase in moisture on Wednesday, mainly across the mountains,
will lead to some weak instability and scattered convection. Temps
will be a few degrees below normal. Moisture increases significantly
Wednesday night into Thursday with clouds and precip developing
across the area. Instability will again be weak, so thunder chances
will be limited even though showers will numerous for most of the
area. There could even be the remnant of organized convection
Wednesday night or Thursday increasing QPF values. With the clouds
and precip in place, Highs on Thursday will be around 10 degrees
below normal.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 210 PM EDT Monday: The upper pattern becomes nearly zonal this
period with a series of short waves moving through the flow and
across the area. Southerly low level flow remains over the area as
there is a squeeze play between a frontal boundary to our north and
southwest that never quite arrive. The front to the southwest
dissipates by Sunday with the northern front moving away to the
north. A cold front then approaches the area front the NW on Monday.
The result is at least scattered diurnal convection with the
moisture and weak to moderate instability each day. With the flow
pattern, there could be remnant organized convection to deal with as
well, but chance and timing is very uncertain at this time. Highs
around 5 degrees below normal on Friday rise to a few degrees above
normal by Sunday and Monday. Lows start our near normal rising to a
few degrees above normal.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Conditions look to be generally good VFR
with light winds through Tuesday. Some isolated weak thunder
showers will become more isolated tonight. Though some rain and
wind gusts from storm outflows will be possible overnight, chances
are too low at anyone point to put in TAFs. Rain and storm chances
Tuesday afternoon will be low as well, though KCLT is alone among
the TAF sites for being in the zone of slightly better instability
where thunder will be possible Tuesday afternoon, but only around a
20% chance. Continued northwesterly flow aloft with a broad surface
high over the Great Lakes, will keep winds with a light northerly to
northeasterly bias, when not VRB. Dry advection will reduce chances
for fog, even at KAVL and KHKY, Tuesday morning. A few high clouds
overnight along with afternoon mid-level cumulus with bases around
5000 ft AGL will be the main cloud issues.
Outlook: Better shower and thunderstorm chances return mid to late
week. Fog and low stratus will be possible in the mountain valleys
each morning.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...AR/WJM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...WJM
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
810 PM CDT Mon Jul 31 2023
.SYNOPSIS...
Issued at 809 PM CDT Mon Jul 31 2023
Partly cloudy skies will prevail across central and southeast
Illinois tonight and Tuesday. Isolated showers and thunderstorms
will be possible southwest of a Macomb to Springfield line, with
dry conditions expected elsewhere. Low temperatures tonight will
drop into the lower to middle 60s, while highs on Tuesday top out
in the middle to upper 80s.
&&
.UPDATE...
Issued at 809 PM CDT Mon Jul 31 2023
High pressure is centered over Michigan this evening and will
continue to result in fair weather across central Illinois
overnight. A few showers over north central Illinois should fade
away with sunset, and showers along the Mississippi River will are
expected to stay mainly in Missouri or at least near the River.
Temperatures are on track to fall into the lower to mid 60s
overnight.
Deubelbeiss
&&
.SHORT TERM... (Tonight and Tuesday)
Issued at 312 PM CDT Mon Jul 31 2023
19z/2pm surface analysis shows a stationary frontal boundary
extending from Kansas southeastward to northern Alabama...while
high pressure remains anchored over the Great Lakes. An area of
showers with a few embedded thunderstorms continues to track
along/north of the boundary from central Missouri into far
southern Illinois. This precip will remain W/SW of the KILX CWA
for the balance of the afternoon/evening. Models have consistently
shown additional convection forming north of the boundary
overnight as the nocturnal low-level jet energizes: however, 12z
CAM consensus has shifted the track of the storms further SW. As a
result, think central Illinois will be largely missed tonight into
Tuesday. Have included low chance PoPs southwest of a Macomb to
Springfield line in case a few showers stray that far
northeastward, but think most locations will remain dry. Lows
tonight will range from around 60 degrees near the Indiana border
to the middle 60s in the Illinois River Valley. Highs on Tuesday
will top out in the middle to upper 80s.
Barnes
.LONG TERM... (Wednesday through Next Monday)
Issued at 312 PM CDT Mon Jul 31 2023
Prominent upper ridge centered over the southern Plains will edge
eastward over the next couple of days: however, its progress will
be suppressed by a deep low over Quebec. As a result, the main storm
track will shift into parts of central Illinois by mid-week. While
synoptic models such as the GFS are bullish with bringing nocturnal
convection into the area Tuesday night/Wednesday morning, CAMs
such as the HRRR and WRF-ARW tend to keep the activity a bit
further W/SW over Missouri into far western Illinois. Given clear
trend, have confined PoPs to locations southwest of a Peoria to
Mattoon line Tuesday night.
A short-wave trough embedded within the broad northwesterly flow
pattern will track through Illinois on Wednesday...triggering
scattered showers and thunderstorms across the board...particularly
during the afternoon and evening. As the wave departs, convection
will get pushed southward on Thursday, mainly focused along/south
of I-70. After that, largely dry weather will be on tap for Friday
and Saturday before another short-wave potentially increases
convective coverage by Sunday/Monday.
Bottom line this week: Temperatures will remain near normal for
this time of year with no oppressive heat/humidity on the horizon.
Rainfall will be greatest along/southwest of a Macomb...to
Springfield...to Effingham line where over 1 inch will be likely.
Further northeast, very little rainfall is expected along the I-74
corridor.
Barnes
&&
.AVIATION... (For the 00z TAFs through 00z Tuesday Evening)
Issued at 609 PM CDT Mon Jul 31 2023
High pressure is centered over Lake Michigan this evening and will
slowly drift east across Michigan Tuesday. Light SE/SSE winds
will prevail across central Illinois, picking up to around 10 kt
during the day Tuesday. VFR conditions will prevail through the
period.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1020 PM EDT Mon Jul 31 2023
.UPDATE...
Issued at 1019 PM EDT MON JUL 31 2023
Showers in southeast KY finally dried up earlier in the evening,
and the rest of the night will be dry. Satellite imagery shows
fog initiating where rain occurred in valleys of Knott, Floyd,
Pike, and Letcher counties. It will continue to spread, with
additional development also over the Cumberland drainage basin,
where lower dew points are slower to advect in.
UPDATE Issued at 450 PM EDT MON JUL 31 2023
Radar shows showers have redeveloped in extreme eastern KY. The
HRRR shows this about an hour later than it is actually happening.
Have added a POP back into the forecast for a few hours based on
this.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 435 PM EDT MON JUL 31 2023
20Z sfc analysis shows weak high pressure nudging into eastern
Kentucky but not effective enough to keep convection from over
achieving again this afternoon on account of some dynamics aloft
and still somewhat elevated sfc dewpoints. The best coverage
appeared to be an hour or so ago with the small threat continuing
for the far southeast portions of the CWA under partly to mostly
sunny skies. Due in large part to this, temperatures vary from
the mid 80s south to mid 70s in places that saw the rain.
Meanwhile, amid generally north winds of 5 to 10 mph, dewpoints
ranged from the low 60s north to the upper 60s in the head waters
of the Kentucky.
The models and ensembles continue to be in good agreement aloft
through the short term portion of the forecast. They all depict a
fairly steady state of mid level northwest flow through Kentucky
between strong ridging holding forth over the Southern Plains and
deep broad troughing over eastern Canada. Within this flow,
several impulses will pass through with the strongest crossing
this afternoon and probably helping the ongoing small convection
threat. Just a couple of weaker ones follow later tonight and on
Tuesday while heights gradually rise due to the ridge easing
eastward through mid-week. Again the limited model and ensemble
spread supported using the blended NBM as the starting point of
the grids with only minor adjustments.
Sensible weather will feature a generally quiet night with the
dissipation of the convection in the far southeast early this
evening. Mostly clear skies and light winds will lead to another
night of decent radiational cooling. Accordingly, expect a
moderate and more typical ridge to valley temperature split
through the night. Also anticipate river valley fog forming later
tonight but probably not as expansive or thick as it was this
morning. The main area for thicker fog will be for places that saw
the rain this afternoon - basically southeast of KJKL. The models
are insistent that Tuesday will be dry as high pressure moves
more completely over eastern Kentucky with temperatures a bit
higher than today for most places while dewpoints come in a touch
drier. Likewise, Tuesday night will see more in the way of a
ridge to valley temperature difference along with renewed late
night fog in the river valleys.
Again adjusted the NBM temperature grids the most in order to
account for terrain distinctions tonight and Tuesday night while,
aside from the activity over the next few hours in the southeast,
in concurrence of the latest HRRR, the PoPs were kept in the lower
single digits.
.LONG TERM...(Wednesday through Monday)
Issued at 331 PM EDT MON JUL 31 2023
The height falls from the east coast wave will relent by
Wednesday, and we will see some slight height rises as a result.
This will leave the area mostly dry, with highs topping out in the
low to mid 80s for most locations. After this, the mid-level
ridge begins shifting west, and we begin to see our pattern shift
to being locally zonal. This will result in the Ohio Valley
getting into the convective ring of fire, so to speak, or seeing
rounds of MCS activity. This results in some uncertainties in the
chances of rainfall as we move into the late week and this
weekend. However, the NBM is bringing a decent shot for much of
the area Thursday at 40–70 percent, and there seems to be decent
model consensus on this among the ensembles. This also matches the
increasing PWATs greater than 1.5 inches by Thursday based on the
ensemble. The EPS EFI also shows some signals for heavier rain
Thursday, and this will have to be watched given the uncertainties
that exist this far out. There is, however, a fair amount of
spread in afternoon high temperatures Thursday, with NBM showing
78 for the 25th percentile and 85 for the 75th percentile. This is
likely a result of periods of convection, and the NBM
deterministic numbers seem reasonable at this point for Thursday.
On Friday, we see rain chances reduce to the 30–60 percent range,
and again, this seems reasonable given a fair amount of
uncertainty on the potential for MCS activity from time to time.
Overall, this will keep temperatures near normal for this time of
year through Friday.
By the end of the period, quite a bit of uncertainty had been
noted among the ensemble systems and deterministic models. The one
thing noted, while subtle, is the potential for some height
rises. The outlier ensemble system seems to be the Canadian, which
wants to be a little more bullish with the height falls. Overall,
NBM does want to show increasing afternoon highs into the mid- to
upper 80s, but again, this could easily bust part of the forecast
with afternoon convection remaining a concern. The chances of
greater than 85 degrees for afternoon highs are peaking on Sunday
at 64 percent at JKL. That said, The NBM keeps generally 30 to 40
percent chances of rain and thunderstorms. This certainly does
match the overall, more quasi-zonal pattern that seems to be
setting up based on the ensemble means and deterministic
solutions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 655 PM EDT MON JUL 31 2023
The only concern during the period will be late night and early
morning fog bringing IFR or worse conditions in some locations.
Fog is forecast to develop first in the valleys of larger streams
and then spread. It should be most prevalent in the Cumberland
drainage basin and where it rained substantially this afternoon.
Outside of fog, VFR conditions are expected.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GREIF
LONG TERM...DJ
AVIATION...HAL
Area Forecast Discussion
National Weather Service Louisville KY
751 PM EDT Mon Jul 31 2023
...Updated Aviation Discussion...
.Short Term...(This evening through Tuesday)
Issued at 305 PM EDT Mon Jul 31 2023
It is an all-around pleasant day weather-wise across the Ohio and
Tennessee valleys as temperatures in the 80s and dewpoints in the
60s (some 50s in southern IN) have combined with mostly sunny skies.
Lingering H85 moisture has allowed for the development of a
scattered cu field for areas mainly east of I-65. These clouds
should gradually dissipate as we head through the afternoon and
evening hours, though a few mid-to-high level clouds from a
disturbance moving through the lower Missouri Valley may stream
across areas west of Interstate 65.
Tonight, dry NW flow aloft will continue across our region as we
remain sandwiched in between upper-level ridging over the southern
Plains and troughing along the east coast of the US. At the surface,
high pressure will remain just north of the Ohio Valley, sliding
gradually eastward overnight into tomorrow morning. Light winds,
mostly clear skies, and dry low-level air will allow temperatures to
cool quite efficiently tonight. Low temperatures should bottom out
in the upper 50s and low-to-mid 60s across most locations, with the
coolest readings expected across rural portions of southern IN and
the KY Bluegrass. Once again, some patchy fog can`t be completely
ruled out in the Cumberland River valley, but coverage and thickness
should be less than this morning thanks to drier air near the
surface.
Tuesday should be another stellar weather day across the region,
with temperatures in the 80s and low dewpoints expected to continue
under mostly sunny skies. Winds will gradually veer more
northeasterly by Tuesday afternoon, with wind speeds expected
between 5-10 mph. The only caveat to tomorrow`s forecast is a plume
of wildfire smoke from Canada that will attempt to push into the
region from the north during the afternoon and evening hours. HRRR
smoke guidance keeps the bulk of the vertically integrated smoke to
our north, and near-surface smoke is not expected to reach
sufficient levels to cause issues at this time. As a result of low
confidence and low probability on impacts from smoke, we`ll continue
to abstain from haze mention in the forecast for now.
.Long Term...(Tuesday night through Monday)
Issued at 215 PM EDT Mon Jul 31 2023
Pattern change will come midweek, as high pressure bringing us the
dry conditions today and Tuesday will shift eastward and start
bringing us some more moisture on the backside. Northwest flow aloft
will bring several difficult to time waves across the region,
bringing better rain chances in the Wed afternoon through Friday
night time period. Timing of those waves will make temperature
forecasts more challenging, but in general it looks like we should
avoid the extra hot temperatures we saw at the end of last week.
Confidence in rain chances will be highest in the mid range and then
taper back toward climo, mostly 20-30 percent each day, given that
difficulty in timing. For the weekend and into early next week, flow
aloft will become more zonal as the ridge over the southern U.S.
weakens/shifts south a little. How much it gets shifted southward is
in question, with the Grand Ensemble of global models showing a wide
range of solutions...so again that`s the main reason to trend
towards climo for now.
&&
.Aviation...(00Z TAF Issuance)
Issued at 740 PM EDT Mon Jul 31 2023
Prevailing VFR conditions through the overnight and into tomorrow.
Sfc high situated over the Great Lakes will continue to provide
mostly clear skies overnight across the Ohio Valley. A dissipating
complex of showers and storms may work some high clouds over western
and parts of southern KY this evening but should remain mainly clear
as for sky conditions go, especially for BWG. Going to keep winds
prevailing out of the north-northwest through most of the forecast
period and keep them generally under 10kts. While some patchy fog
could be an issue in parts of our area, do not expect this to be an
issue at any of the TAF sites overnight into the morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Short Term...CSG
Long Term...RJS
Aviation...BTN
Area Forecast Discussion
National Weather Service Medford OR
831 PM PDT Mon Jul 31 2023
.DISCUSSION...The current trend remains for temperatures to
gradually warm into the weekend when near-triple digit highs are
possible in west side valleys. The main updates for this evening
were to show the chance of smoke in haze for the short- term
forecast. With the northerly winds today, there was more smoke
from the Bedrock fire spotted in Medford. There is now haze in
parts of Jackson County for Tuesday afternoon/evening with support
from the earlier observations. The trend of afternoon gusts near
20-25 knots has been kept in the grids east of the Cascades.
Please review the previous discussion for more details on the
forecast and the late week thunderstorm chances. -Hermansen
&&
.AVIATION...01/00Z TAFs...Inland areas (including KRBG, KMFR, and
KLMT) can expect VFR conditions to continue through the TAF period,
with periods of normal breezy summer winds this afternoon. After an
afternoon of gusty northerly winds, the marine stratus is again
expected to develop later this evening for the coast into the Camas
Valley. This will continue through the overnight hours before
returning to MVFR conditions later in the morning.
-Schaaf/Hermansen
&&
.MARINE...Updated 800 PM PDT Monday, July 31, 2023...Gusty north
winds and steep, wind-driven seas will persist south of Cape Blanco
into Wednesday morning, with the strongest winds expected south of
Gold Beach. Isolated gales are possible in this area through Tuesday
afternoon, but the thermal trough will weaken later Tuesday into
Wednesday and north winds will trend lower. The thermal trough is
likely to strengthen again at the end of the week, with steep to
very steep seas likely returning. /BR-y
&&
.PREV DISCUSSION... /Issued 241 PM PDT Mon Jul 31 2023/
DISCUSSION...An upper level ridge centered over the southern United
States is deepening, keeping lower pressure systems in the Gulf of
Alaska away from the area. This will support slightly warmer
temperatures today, with highs reaching the high 80s to mid 90s.
Coastal areas will stay in the low to mid 70s. Skies will be clear
tonight with the exception of some east side development over higher
terrain and marine stratus returning this evening. HRRR smoke
guidance is showing some accumulation in southern Curry and
Josephine counties this evening from the Flat Fire and across Lake
and Klamath counties from the Bedrock Fire, but should clear out as
winds pick up on Tuesday.
With the stability of the southern ridge, conditions are expected to
be steady through the week. One exception to the consistency will be
chances of thunderstorms east of the Cascades on Thursday and Friday
afternoon and evening. Movement in the center of the ridge`s high
pressure will let moisture move over the western United States,
bringing precipitable water amounts in the region to 0.7 to 1.0
inches through the second half of the week. Convective instability
and upper level vorticity could provide uplift to that moisture that
could allow thunderstorms to develop. Activity is expected to be
isolated, but could potentially occur anywhere across the east side.
Future guidance may allow for more specific areas to be considered.
Slight changes in wind or moisture patterns could change the
thunderstorm chances, either making them more or less likely.
This weekend, that southern high pressure center looks to move west
to the California/Baja California area. This would put northern
California and southern Oregon firmly under the ridge. Future model
guidance does show a further warming trend this weekend, with west
side valleys forecast to be in the high 90s to low 100s this weekend
into early next week. The upper ridge does look to flatten quickly,
which would result in zonal flow and more seasonal temperatures.
-TAD
FIRE WEATHER...Updated 200 PM PDT Monday, July 31, 2023...A ridge
of high pressure is expected to sneak into our CWA over the next few
days, leading to warmer overall temperatures which will decrease the
minimum relative humidity values to below critical thresholds for
Northern California and east of the Cascades. Winds will be more
relaxed, keeping many regions out of red flag criteria. However, in
FWZ-280 there will be a concentrated area of red flag conditions
Tuesday afternoon in the Salmon Mountain range, but these do not
meet the duration criteria. In addition, as a result of the building
high pressure the marine push extent into Douglas County and other
coastal valleys should trend weaker as there is less onshore wind.
The next focus will be on the increased chance for thunderstorms
east of the Cascades later next week. These storms will start on
Thursday afternoon (15-30% chance), peak on Friday (20-40% chance),
and be more isolated on Saturday (10-20%). There is high confidence
that storms will start off dry on Thursday, even under the storm
cores (10% chance that more than 0.1" falls). By Friday, storms may
begin to moisten up, with the chance of a wetting rain increasing up
to 20-40% (higher to the east). Storms Thursday and Friday should
have a northbound storm motion at about 15 mph, and on Saturday,
storms are forecasted to move south at around 10mph.
-Danny/Kilometers
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...None.
PACIFIC COASTAL WATERS...Small Craft Advisory until 8 AM PDT
Wednesday for PZZ356-376.
&&
$$
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 259 PM CDT Mon Jul 31 2023
Key Messages:
- Periodic chances for thunderstorms and rain showers for most of
the week. There is a Marginal Risk for severe weather tomorrow.
- Temperatures forecast to be near seasonal norms though relative
humidity will remain high.
Today through Wednesday:
Early day rain and cloud cover will help make today one of the
coolest days the area has had in some time. A few locations may
not even top 80 degrees. In general, the next couple of days will
be warmer as the mid-level ridge moves over the central CONUS.
There will also be a few chances for additional precipitation as
weak upper level systems move over the forecast area. This upper
level northwest flow pattern has proved difficult to forecast with
high certainty on the exactly where and when precipitation will
occur. The pattern will be active, but severe weather parameters
are marginal at best most days this week. The first chance for
precipitation will this evening in southwest Iowa. Of the CAMs,
only the HRRR is suggesting a band of rains showers along a weak
boundary in that area. With MLCAPE values under 500 J/kg and only
modest shear, severe weather is not expected.
The next chance for precipitation will be tomorrow as a remnants
of overnight convection are expected to move across Nebraska and
into northeast Nebraska. Those remnants will be timed somewhat
well with peak afternoon heating which could help re-invigorate
the system. However, MLCAPE is forecast to be under 1000 J/kg.
Deep layer bulk shear (0-6 km) will be near 50 kts. With adequate
low level moisture and a warm air advection regime, there is a
chance a storm or two could become severe with a capability of
producing large hail or damaging wind gusts. There is a Marginal
Risk (Level 1 out of 5) for severe weather.
Another chance for precipitation will be possible very late
Tuesday and into Wednesday morning. A mid-level shortwave will
move off the Rocky Mountains and into the northern Plains. While
there may be a severe risk early with this chance, it will quickly
fade as instability and shear will be lacking.
Thursday through Sunday:
Near daily precipitation chances will continue through this
period. Temperatures will be near the climatic average (Hi: 88,
Low: 68). A frontal passage is expected late Saturday or early
Sunday which will result in temperatures in the low 80s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 610 PM CDT Mon Jul 31 2023
MVFR ceilings will continue to scatter out over the next few
hours. A few spotty showers and storms may develop this evening,
but should be confined to western Iowa, east of the TAF sites.
Patchy fog and MVFR to IFR ceilings are expected to creep into
parts of central and northeast Nebraska early Tuesday morning.
While fog will be relatively patchy, lower ceilings could reach
KOFK from around 10 to 16Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Fajman
AVIATION...KG
Area Forecast Discussion
National Weather Service Phoenix AZ
513 PM MST Mon Jul 31 2023
.UPDATE...Updated 00z Aviation Discussion...
&&
.SYNOPSIS...
An upper level weather disturbance will continue to impact the
region today with adequate monsoon moisture bringing higher than
normal chances for showers and thunderstorms across much of
southern Arizona. While strong gusty winds and dense blowing dust
will be the primary weather hazards, some locations could
experience heavy rainfall. This wetter pattern will be short lived
as abnormally dry conditions are expected to return during the
latter half of the week. After near normal temperatures through
Tuesday, the latter half of the week will see a modest warming
trend with highs once again topping 110 degrees over much of the
lower deserts by Friday.
&&
.DISCUSSION...
Light rain associated with last night’s MCS and residual MCV
continue to dissipate across southeastern California. Further east
across Arizona, skies are mostly sunny, but conditions are
several degrees cooler and more moist than 24 hours ago. With
surface dewpoints in the 60s, there is only a 10 percent chance
Sky Harbor Airport will reach 110 degrees. The historic streak of
110+ degree days stands at 31 days and that will likely end today.
Latest water vapor and RAP streamline analysis reveal the
inverted trough is lifting northward through Sonora. Meanwhile,
mesoanalysis indicates PWATs are running higher than normal,
generally between 1.3 and 1.7 inches. Unlike past days, latest
ACARS soundings from KPHX show 12+ g/kg mixing ratios extending
from the surface through 850 mb. MLCAPEs are also quite robust,
given the abundant moisture and well-below normal 500 mb
temperatures approaching -8 degrees C.
On the ascending side of the trough, convection has already
initiated across the favored areas of the higher terrain,
including the Mogollon Rim, White Mountains and the sky islands of
southeastern Arizona. A 20 kt east-southeasterly flow will
promote the propagation of these cells off the higher terrain and
into the lower deserts this afternoon.
Numerous CAMs within the HREF suggest the convection across
eastern and southeastern Arizona will migrate northwestward into
central Arizona this afternoon before increasing in coverage
across northwestern Maricopa County this evening, where moisture
convergence will be maximized. The official forecast reflects the
NBM, with PoPs of around 60-70 percent in the Valley. With above
normal PWATs, the strongest cells will be capable of producing
heavy rainfall and localized flooding. There is also a 70 percent
chance of wind gusts above 35 mph, which has the potential to
produce areas of blowing dust across portions of Pinal County and
the Phoenix Metro area. Although widespread damaging winds are not
anticipated, there is a marginal risk (5 to 10 percent) of severe
wind gusts across central and southern Arizona.
One caveat remains the potential for shower and thunderstorm
activity to skip over portions of the Valley, where CIN cannot be
eroded by outflow pushing northwestward through Pinal County.
Several runs of the HRRR have trended towards this scenario. On
the other end of the spectrum, the U of A WRF-GFS suggests little
inhibition with intense convection moving through central
Arizona.
&&
.PREVIOUS DISCUSSION...
Starting Tuesday, our region will fall under an increasingly dry
southwesterly flow with the sub-tropical high center positioned
over the Southern Plains. However, there should still be adequate
boundary layer moisture with MUCAPEs of around 500-750 J/kg in
place for isolated to possibly scattered afternoon showers and
thunderstorms focused more over higher terrain areas. The south
southwesterly steering flow on Tuesday is generally not favorable
for long-lasting outflows or widespread thunderstorm development,
so coverage over the lower deserts is likely to be fairly limited.
By Wednesday, low level mixing ratios are forecast to drop to
around 8 g/kg suggesting only fairly limited higher terrain
shower and thunderstorm potential.
For late this week and through the weekend, the sub-tropical high
is forecast to shift southward and become elongated stretching
from well west of Baja through the Southern Plains. This synoptic
set-up is very similar to the first week or two of July when it
was nearly impossible to get any meaningful monsoon moisture into
Arizona. Unfortunately, ensemble guidance is heavily favoring a
continued drying trend through the weekend as PWATs drop below 1"
across the entire Desert Southwest. This scenario should
essentially end any storm chances across the area by the weekend
with maybe only the highest peaks seeing any limited convection.
As of now, this dry weather pattern seems to take hold by the
weekend, potentially lasting through all of next week.
The near normal temperatures for today and Tuesday will steadily
climb higher during the latter half of the week with forecast
highs over much of the lower deserts again above 110 degrees by
Friday or Saturday. Ensemble guidance at least favors a more
active flow pattern across the northern and central U.S. starting
this weekend into next week, so it seems likely it will at least
limit the strength of the sub-tropical high as it keeps it
centered south of the region. For now, there looks to be some
localized areas of Major HeatRisk forming by the weekend but it
seems unlikely we will return to widespread Excessive Heat
Warnings under this pattern.
&&
.AVIATION...Updated at 0010Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The main aviation concern through this evening will be the
potential for gusty outflow winds emanating from thunderstorm
activity across southeast AZ. At this time, based on the latest
trends, it appears the outflow winds will be moving through the
terminals between 02-05z with winds switching out of the southeast
with gusts potentially exceeding 30 kts as well as reduced
visibilities due to BLDU. There is lower confidence, however, for
thunderstorm activity to directly affect the terminals so the
mention of VCTS have only been mentioned in the TAF at this time.
Conditions should improve after 06z with a return to the typical
nocturnal wind pattern. Much calmer conditions are expected for
Tuesday with the typical diurnal wind pattern expected along with
generally mostly clear skies with just a FEW mid to high-level
clouds.
Southeast California/Southwest Arizona including KIPL and KBLH:
At KIPL, winds will generally be from the southwest through this
evening into the overnight period, switching from the southeast by
the early morning hours with speeds generally near 10 kts. At
KBLH, winds will generally fluctuate from the south to south-
southwest with some gusts nearing 20 kts through early this
evening and once again for Tuesday afternoon. FEW-SCT mid to
high-level clouds will pass through the region during the period.
&&
.FIRE WEATHER...
The unsettled weather pattern will continue today with better
shower and thunderstorm chances across eastern and south-central
Arizona. Gusty erratic outflow winds are the greatest concern
with these storms, though some beneficial wetting rainfall is
likely for some areas. Drier conditions will begin to move in on
Tuesday, but lingering moisture should be enough for isolated to
scattered showers and thunderstorms. Minimum afternoon humidity
levels will fall into a 20-30% range through Tuesday, while
temperatures fall back closer to normal readings. For the latter
half of the week, gradual drying conditions will eventually end
storm chances across the lower deserts on Wednesday and even over
the high terrain by the coming weekend. Temperatures will once
again warm back to above normal readings starting Wednesday, while
minimum humidities on Wednesday dip back into a 10-20% range and
likely even into the single digits by Friday.
&&
.CLIMATE...
Active Streaks:
PHOENIX
1. Consecutive days of high temperatures 110F or greater: longest
on record at 31 days (previous record: 18 days in June 1974)
2. Consecutive days of no measurable precipitation: 14th longest
on record at 130 days
YUMA
1. Consecutive days of low temperatures 85F or greater: Tied for
longest on record at 20 days
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Kuhlman
AVIATION...Lojero
FIRE WEATHER...Kuhlman
Area Forecast Discussion
National Weather Service Tulsa OK
905 PM CDT Mon Jul 31 2023
...New SHORT TERM...
.SHORT TERM...
(The rest of tonight)
Issued at 902 PM CDT Mon Jul 31 2023
Conditions tonight appear more uneventful than those of 24 hours
ago, with any thunderstorm chances across parts of northwest
Arkansas remaining likely to hold off until tomorrow morning - if
they occur this far west as the HRRR continues to point toward.
Expect a warm night across the area, with mainly high clouds. The
forecast has been updated to remove the expired heat advisory from
this afternoon, but otherwise, things appear on track.
&&
.LONG TERM...
(Tuesday through Monday)
Issued at 205 PM CDT Mon Jul 31 2023
The heat intensity is expected to peak on Tuesday thru Thursday,
and then tail off going into the weekend. The H5 ridge center will
shift southeast Wednesday and then broaden and flatten toward the
end of the week. Based on forecast highs and dewpoints for
Tuesday, heat warnings will be issued for a portion of NE OK
including TUL (for ambient temp) and for the lower Ark River
valley down toward FSM (for heat index). Heat headlines are likely
to continue for much of this week. There has been indications in
the deterministic data that we could see a front push into the
region next weekend and could be followed by a period of unsettled
weather going into early next week. Some relief from heat and
some rain are at least possible. Before then, fire weather
concerns may begin to increase this week as vegetation dries out
and winds kick up. Some fire weather products may be needed as
well.
Lacy
&&
.AVIATION...
(00Z TAFS)
Issued at 621 PM CDT Mon Jul 31 2023
VFR conditions will prevail through the forecast period.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 81 104 83 104 / 0 0 0 0
FSM 77 102 78 104 / 0 10 0 0
MLC 77 103 79 103 / 0 0 0 0
BVO 73 104 76 104 / 0 0 0 0
FYV 73 98 74 99 / 0 10 0 0
BYV 73 94 75 98 / 10 10 0 10
MKO 76 102 78 102 / 0 0 0 0
MIO 76 101 80 103 / 0 10 0 0
F10 77 102 80 101 / 0 0 0 0
HHW 76 101 78 102 / 0 0 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory from 11 AM to 9 PM CDT Tuesday for OKZ049-053-
056>058-061>063-065>071-073>075.
Excessive Heat Warning from 11 AM to 9 PM CDT Tuesday for OKZ054-
055-059-060-064-072-076.
AR...Heat Advisory from 11 AM to 9 PM CDT Tuesday for ARZ001-002-010-
011.
Excessive Heat Warning from 11 AM to 9 PM CDT Tuesday for ARZ019-
020-029.
&&
$$
SHORT TERM...22
LONG TERM....30
AVIATION...05
Area Forecast Discussion
National Weather Service Tucson AZ
222 PM MST Mon Jul 31 2023
.SYNOPSIS...Showers and thunderstorms are likely across most of
the area this afternoon and evening. Some will be strong to
severe and capable of heavy rainfall leading to flash flooding.
Temperatures cool to near normal today through Wednesday. Rain
chances dwindle after Tuesday as drier air moves in. Hotter
temperatures return by Friday into the weekend.
&&
.DISCUSSION...Scattered thunderstorms kicking off the early
afternoon. We`ve picked up some decent shear and brisk storm
movement while dropping from 1.5 inches PW to around 1.35 or so.
Latest HRRR still has us on track for elevated strong
thunderstorm coverage from mid afternoon into the early evening
hours. We`re just barely holding on to a sub 100 temperature at
the airport (which would be the first since mid June), but will
likely push past 100 over the next hour or two.
For Tuesday, expect modest drying and weak subsidence as the
impulse that is helping to organize our storms today shifts
northward and continues to weaken. This will limit storm coverage
quite a bit compared to what`s expected today.
For Wednesday through the weekend, it looks hotter and drier.
Thursday through Saturday could see a complete shut-down of
seasonal thunderstorms as the high pressure ridge that has been
east of the area builds overhead and into northwest Mexico. That`s
a firm blocking position combined with warmer mid levels to
inhibit convection. Back to record highs Friday through Sunday,
with a decent chance of 1 or more additional 110 temperatures
added to the summer total for Tucson.
Ensemble means are hinting that the western portion of the ridge
will break down and once again see a high center reconsolidating
to our east. That could open our corner of the state up again for
a thunderstorm return around next Monday or so. Tropics are
heating up again as well.
&&
.AVIATION...valid through 02/00Z.
Scattered to widespread SHRA/TSRA with gusty outflow winds
between 40-50 kts along with VSBY restrictions to 3SM or less
possible. Showers and thunderstorms diminishing by late evening
with partial clearing overnight. Isolated to scattered -SHRA/-TSRA
return after 01/19Z. Outside of thunderstorm outflows, afternoon
SFC winds will be WLY at KTUS, and SLY at KOLS and KDUG at around
15 kts becoming light and terrain driven overnight. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Scattered to widespread afternoon and evening
showers and thunderstorms are expected across southeast Arizona.
Storms will be capable of producing strong, gusty, and erratic
outflow winds of 40-60 mph along with heavy rain. On Tuesday, storms
will have less coverage and intensity with wind gusts up to 45 mph
possible. Although sustained 20-foot winds will generally remain
under 15 mph, gusts to around 25 mph may occur. Temperatures
closer to normals today and tomorrow but will quickly heat back
up Wednesday and beyond, with near record highs returning by
Friday. Valley min RH readings will generally range between 20-
30% today and tomorrow with conditions drying out to 10-20% for
Wednesday and beyond.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Meyer
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service Las Vegas NV
158 PM PDT Mon Jul 31 2023
.SYNOPSIS...Monsoon moisture has spread into the region, which will
result in greater thunderstorm coverage over northwest Arizona,
southern Nevada, and southeast California through Tuesday.
Thunderstorm chances will spread into south central Nevada Wednesday
before moving away to the northeast Thursday and Friday. Stronger
storms will be capable of producing heavy rain with localized flash
flooding and strong winds. Drier conditions Thursday and beyond will
allow temperatures to return to near to above normal late in the
week into the weekend.
&&
.SHORT TERM...through Wednesday night. Early afternoon satellite
loop showed very impressive mesoscale convective vortex, left over
from last night`s complex that went through Yuma, spinning westward
over the northern Baja just south of Campo. This feature had brought
a roughly north-south oriented band of clouds and a few
thunderstorms which has been moving west all day, and was roughly
from Barstow through the Nevada National Security Site early this
afternoon. Farther east, where skies had cleared and abundant low
level moisture was present, thunderstorms were firing over the
mountains of Mohave, Clark, and Lincoln counties. Expect storms to
increase in coverage as the afternoon goes on, and at least some
storms should persist all night in the moist and unstable
environment. Speaking of moist, surface dewpoints in the 50s and 60s
and precipitable water as high as 1.75 inches will make flash
flooding the main threat with storms. There is some clustering among
the high resolution models showing precip in the Las Vegas Valley
Tuesday morning, which could stabilize things for the afternoon, but
confidence in this exact placement and timing is low. Regardless,
areas which don`t see morning precip and/or thick cloud cover during
the day will be susceptible to thunderstorm development, with heavy
rain and flash flooding the main threat again. For Wednesday, more
stable air starts to work in from the southwest, which should reduce
thunderstorm coverage over southeast California, although southern
Nevada and northwest Arizona will likely have one more active day.
The York Fire is another issue worth discussing. As of this morning,
the fire was up to 77,000 acres, and had burned across the state
line from the Mojave National Preserve into Clark County. The fire
was producing lots of smoke, which the HRRR Smoke model expects to
continue affecting Las Vegas. The increased humidity in the area
will act to slow the fire`s spread, and any rain on the fire will be
helpful. On the flip side of that coin, any thunderstorm outflow
winds could push the fire erratically, and any lightning strikes
outside of rain cores could start new fires.
.LONG TERM...Thursday through the weekend.
Southwesterly flow finally begins to scour out the monsoonal
moisture on Thursday, with PoPs largely limited to northeastern
portions of the CWA. By Friday, precip chances are pretty much gone
as the upper-level high begins to expand westward. Over the weekend,
the elongated ridge becomes centered near Yuma, placing us under
light westerly flow and anomalously high 500mb heights. The end
result of this development is dry conditions and slightly above-
normal temperatures. It`s probable that these warm and dry
conditions last well into August. The latest CPC 8-14 day outlook
keeps our temperatures slightly above normal and precipitation below
normal through mid-August.
&&
.AVIATION...For Harry Reid...Easterly winds early this afternoon
will turn southeast by late afternoon, with occasional gusts to 15kt
possible after 21Z. Scattered thunderstorms are also possible in
the vicinity of the terminal from mid-afternoon through mid-evening,
any of which will be capable of generating outflow winds to 30kts
from the direction of the storms. A lull in the storm activity is
expected overnight, but additional storms are possible by tomorrow
afternoon. Reduced surface and slant range visibility can be
expected through the TAF period as smoke from the York Fire in the
Mojave National Preserve continues to spread across the valley.
For the rest of southern Nevada, northwestern Arizona, and
southeastern California...Scattered thunderstorms are expected
across most of the region over the next few days, any of which will
be capable of producing gusty, erratic outflow winds. The best
chances of storms will be near the Vegas area terminals, KDAG, and
KIFP. Storms are also possible near KEED, but chances are a bit
lower. Away from storms, winds will generally follow typical
diurnal trends with speeds of 15kts or less. Some reduction in
surface and slant range visibility can be expected through the TAF
period across Clark, northern Mohave, and eastern San Bernardino
counties as smoke from the York Fire in the Mojave National Preserve
continues to spread across the area.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
SHORT TERM...Morgan
LONG TERM...Woods
AVIATION...Planz
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