Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/01/23
Area Forecast Discussion
National Weather Service Gaylord MI
1152 PM EDT Fri Jun 30 2023
.UPDATE...
Issued at 945 PM EDT Fri Jun 30 2023
Diurnal convection has waned/exited. A recent RAP run squeezes
out a couple of rain showers toward (or even after) daybreak in w
central lower MI, thanks to some mid-level lapse rate steepening.
Will not send the forecast down this road yet.
Surface vsbys have improved everywhere...except near some coastal
areas, especially on Lk Huron. Plenty of marine fog is seen on
Huron (with high dew point air over cool water temps). That snuck
onshore late in the day thanks to lake breezes. Rogers City (PZQ)
has seen dense fog for a few hours now, and vsbys have recently
worsened at Cheboygan (SLH) and OSC. With light winds tonight, and
surface dew points pretty moist in most spots (a few interior
locales like CAD/GLR did mix out this afternoon), fog will become
a more generalized concern thru the night. This will especially
be the case where dew points never mixed out and/or where precip
fell today. Will boost the mention of fog tonight (have already
done so in the Haz Wx Outlook).
Min temps mid 50s to lower 60s.
&&
.NEAR TERM...(Through Tonight)
Issued at 306 PM EDT Fri Jun 30 2023
High Impact Weather Potential: Minimal. A few thunderstorms this
evening?
Pattern Synopsis/Forecast:
Upper level troughing sliding east across the area early this
afternoon, with parent closed mid level circulation centered across
northern Ontario. Weak surface trough/cold front working east
through the region, with exact placement of this surface feature
becoming increasingly diffused as Lake Huron lake breezes develop.
While overall forcing is minimal...enhanced low level moisture and
wind convergence across northeast lower Michigan is helping drive
the development of a few showers and thunderstorms.
Main trough axis will continue to slide east tonight, forcing its
surface reflection to do the same. Weak high pressure will build
into the area in their wake.
Primary Forecast Concerns/Challenges:
Addressing additional shower and thunderstorm chances into this
evening. Temperature and cloud trends through tonight.
Details:
Lake breeze driven surface convergence axes likely to kick off a few
more showers and thunderstorms into early this
evening...particularly across northeast lower Michigan were said
convergence and diurnally-driven instability (up and over 1k+
joules/kg of mixed layer cape) will be maximized and best
juxtaposed. Not expecting any widespread severe weather concerns,
but definitely cannot rule out an isolated severe wind
gust/marginally severe size hail given decent flow through the
convective cloud depth and those backed low level winds along the
lake convergence axes. Expect convection to fall apart heading
through the evening as instability and convergence both wane. Dry
conditions overnight, although cannot rule out some patchy fog again
given moisture rich low levels and light winds. Otherwise, more
clouds the further north one goes, with overnight lows ranging from
the middle 50s to near 60.
&&
.SHORT TERM...(Saturday through Monday)
Issued at 306 PM EDT Fri Jun 30 2023
High Impact Weather Potential: Minimal. Additional thunderstorm
chances at times, but nothing severe expected.
Pattern Synopsis/Forecast:
Broad troughing will remain across the region into early next week,
with main surface based baroclinic axis and attendant deep layer
moisture convergence set to remain off to our south. Still, in
absolute classic northern Michigan warm season convection fashion,
mesoscale processes driven by lake breeze induced surface
convergence axes will likely produce at least the potential for a
few showers and thunderstorms at times.
Primary Forecast Concerns/Challenges:
Addressing additional shower and thunderstorm chances and
temperature/cloud trends.
Details:
Most confident portion of the forecast for this period is the near
to above normal temperatures, with afternoon readings mostly in the
80s. Humidity levels won`t be too extreme, helping keep heat indices
close to those actual temperatures. Just enough diurnally-driven
instability and lake driven surface convergence to perhaps kick off
a few showers/storms Saturday afternoon across northeast lower and
eastern upper Michigan. Weak system passing by to our south Sunday
will likely bring widespread showers across the southern Lakes, with
northern edge of attendant moisture plume and again those lake
convergence axis perhaps kicking off a few showers across our area.
Rinse and repeat for Monday, with just very small chances for
showers in our traditional favored areas of northeast lower
Michigan. Would definitely like to stress most of the area and a
vast majority of the time will be a dry one, with rain confined to
localized areas during this entire period.
.LONG TERM...(Monday night through Friday)
Issued at 306 PM EDT Fri Jun 30 2023
Shortwave troughing over western Canada will progress eastward
towards the Great Lakes region through the middle to end of next
week. A cold front associated with the aformentioned trough will
pass across the CWA will have unsettled weather return to the region.
Tuesday will probably be dry and warm while we wait for the upstream
cold front to arrive. High temperatures Tuesday have the potential
of a few areas seeing 90 degrees. Chances of precipitation increase
midweek as the front arrive. There is uncertainty with regards to
timing of the aforementioned front, chances of precip will be spread
Wednesday through Thursday. This will include a threat for
thunderstorms. Timing of this front will effect the high temperature
forecast, especially on Thursday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1152 PM EDT Fri Jun 30 2023
Fog tonight, especially APN/PLN/CIU.
Additional SHRA/TSRA activity could fire again Saturday
afternoon, with APN/CIU most likely to be impacted. The bigger
aviation impacts will be from BR/FG. Expect APN/CIU/PLN to go IFR
to LIFR at times overnight into early Sat morning. Have added MVFR
vsbys to MBL/TVC.
Light winds.
&&
.MARINE...
Issued at 306 PM EDT Fri Jun 30 2023
Winds and wave will remain below SCA criteria into next week.
Mainly dry weather is expected for the next several days, with only
small chances for showers and thunderstorms...especially across
northern Lake Huron.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JZ
NEAR TERM...MSB
SHORT TERM...MSB
LONG TERM...SJC
AVIATION...JZ
MARINE...MSB
Area Forecast Discussion
National Weather Service La Crosse WI
1046 PM CDT Fri Jun 30 2023
.DISCUSSION...(Tonight through Friday)
Issued at 200 PM CDT Fri Jun 30 2023
Key Messages:
- Scattered shower/storm chances (20-40%) will persist into Sat
night - mostly holding across northeast IA/southwest WI.
- Generally above normal temps into early next week, warmest
Monday/Tuesday. Cooling for the later half of next week.
- A higher chance (50-60%) for widespread showers/storms late Tue
into Wed.
* WEEKEND INTO 4th HOLIDAY - RAIN CHANCES MOSTLY SOUTH, WARMING
Upper level trough currently churning in the lee of the southern
rockies, with ripples in the flow ejecting out of it. At the sfc,
the front that tracked across the area yesterday has lain up west-
east across northern IA into southern WI. Pool of moist, unstable
air hangs further south of there (per SPC RAP analysis). Morning
convection mostly across IA has shifted into IL for the afternoon,
although some spotty showers still lingering westward. Could see
some further development in the vicinity of the sfc boundary,
coupled with any bits of upper level energy. However, RAP holds most
of the MUCAPE south, not providing a rich environment for sustaining
any convection, let alone spark it. CAMS aren`t enthusiastic either.
Think small pops are still warranted across parts of NE IA/SW WI.
tonight into early part of Sat.
Moving into Sat afternoon and night, the upper level trough starts
to press into the mid mississippi river valley with bits of
shortwave energy ejecting eastward out of the trough. The sfc
boundary could sag more southward, but with the ripples in the flow
working more northward, should see an increase in shower/storms
chances across northeast IA/southwest WI. The trough edges east
later Sunday, with shortwave ridging then building in. Rain chances
will be on the wane in the south and looking for a dry Sunday night
into Tuesday. Rain chances (widespread) return later Tue and Wed.
More on that in the next section.
Temperature-wise, seasonable warmth expected through the weekend
with shortwave ridging, southerly flow kicking temps up a bit moving
into Mon/Tue. Some uptick in dewpoints and humidity too, although
not an appreciable factor on heat indices at this time (don`t waver
much from ambient air temp). Clouds and rain chances will keep it a
tad cooler to the south through the weekend.
* TUE/WED RAIN CHANCES...THEN RETURN TO COOLER, LESS HUMID CONDITIONS
The GFS and EC remain on track to slide an upper level trough from
western Canada, across the northern plains and then pushing west-
east through the upper mississippi river valley in the Tue-Wed
frame. Models continue to show some timing differences, which
could/would impact potential for strong/severe risk. SPC cluster
analysis has the preponderance of the GEFS in stronger, slightly
quicker scenarios. The EPS favors weaker and a tad later. Latest
operational runs show the same with the GFS tracking an associated
cold front across the local area Tue afternoon/evening while the EC
is trending toward overnight Tue/Wed morning. Part of the
differences could be overnight convection the GFS develops over the
northern plains Mon night, with residual MCV pushing across the
region later Tue. Not much from the EC in this stead. More of a meso
scale feature, and this far out, confidence not high enough to put
the "eggs" in that basket - yet. Issue here is the model blend will
spread out the rain chances between the 2 potential solutions,
although have trended with higher chances - which looks like the way
to go - but timing could be off. Expect refinement to the timing and
potential risks over the next few days. Bottom-line for 4th of July
celebrations - some threat for showers/storms that could impact
evening festivities.
Cooler and less humid air favored to drop in from Canada post the
mid week system with 850 mb temps slated to drop from around 18 C
Tue to 10 C for Thu. Highs would shake out in the 70s to lower 80s,
close to, perhaps even below the early July normals.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1046 PM CDT Fri Jun 30 2023
A series of shortwave troughs will move east through Iowa. These
systems will provide a broken mid and high cloud deck through the
TAF period.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Rieck
AVIATION...Boyne
Area Forecast Discussion
National Weather Service Burlington VT
956 PM EDT Fri Jun 30 2023
.SYNOPSIS...
An active Saturday is anticipated across the North Country with
scattered showers and thunderstorms expected to develop over
northern New York by late morning into early afternoon. These
showers and storms will slowly push east into the Champlain
Valley and parts of Vermont during the mid afternoon into the
early evening hours. Some storms will be capable of brief gusty
winds, frequent lightning and localized very heavy down pours.
Additional showers are possible on Sunday with more showers and
storms for Monday into Tuesday of next week, with temperatures
holding near normal.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
As of 952 PM EDT Friday...No changes beyond a few minor tweaks
were needed with this update. Partly cloudy skies prevail out
there tonight, along with patchy smoke, mainly from the
Champlain Valley westward. Note that now KPBG and KBTV are
reporting reduced visibility, along with KSLK, KMSS, and KRUT,
which were also reporting HZ or BR earlier this evening. The
latest HRRR near surface smoke trends still show concentration
increasing toward daybreak tomorrow, with conditions improving
by mid/late morning. Therefore the inclusion of patchy smoke
overnight still looks good. Also still anticipating patchy fog
in the favored eastern VT valley locations later tonight. Lows
will be on the muggier side, ranging from the upper 50s to the
upper 60s.
Previous discussion...Fcst focus tonight into Saturday wl be
timing of showers/storms, along with strong/severe potential on
Sat aftn. Initial s/w energy and ribbon of mid lvl moisture
associated with waa aloft is lifting acrs western/northern NY.
This has resulted in some widely scattered activity acrs the
SLV. As additional energy in the developing southwest flow aloft
acrs northern NY tonight with a region of elevated instability,
additional showers with embedded rumbles are possible. Have
continued with chc pops for the SLV to schc for CPV. Based on
925mb wind fields increasing at 15 to 30 knots from west to east
toward 06z, expecting any fog potential wl be confined to the
central/eastern VT valleys, including parts of the NEK. Much
less coverage anticipated tonight. Temps wl stay mild overnight,
especially CPV with southerly winds developing, have lows
ranging from the mid/upper 50s to mid/upper 60s, with near 70F
locally in the BTV metro area.
Saturday...expecting an active wx day with strong to a few svr
storms possible with highest potential acrs northern NY into the
CPV btwn noon and 6 PM. Water vapor indicates our s/w of
interest is crntly located over the central Plains this aftn and
wl race quickly eastward tonight and be located acrs the SLV by
12-15z Sat. Pre- storm analysis indicates a relatively high
level of CAPE, with modest values of shear, suggesting pulse
like storms evolving into multiple cell clusters. Expecting
convection to develop acrs the SLV/western Dacks btwn 11 AM and
1 PM on Saturday and slowly push east into the Dacks and CPV by
mid-aftn. CAPE values look to be in the 1800 to 2400 J/kg range,
supported by sfc temps in the upper 70s to mid 80s and dwpts
well into the 60s. Once again favorable deep layer shear wl be
the limiting factor for well organized convection, but 0 to 6 km
values in the 25 to 35 knot range, should be enough to support
strong to locally a few svr storms.
Given the instability and wind profiles, localized gusty winds
would be primary threat, with small hail secondary. Next
potential item to watch closely with be potential for hydro
related issues, especially as pulse/single cells become more
consolidated into clusters capable of producing very heavy
rainfall rates in a short period of time. PW values btwn 1.50
and 1.75 inches, along with warm cloud depths up to 11 kft,
support the idea of efficient rain producing thunderstorms.
Also, helping in the large scale synoptic scale ascent with
favorable upper lvl divergence is left front quad of an angling
25h jet of 80 to 90 knots acrs northern NY, per latest 15z RAP.
All these ingredients should combined to produce an active day
on Saturday, with primary threat acrs northern NY into the CPV.
SPC and WPC SWO/ERO DY2 conts to place most of our cwa in
marginal, which looks reasonable attm. Areas of showers with
embedded thunder wl linger into the overnight hours, but threat
for strong storms wl quickly diminish by 00z. However, given
boundary draped acrs the region, high pw values, and elongated
s/w energy in the southwest flow aloft localized heavy rainfall
wl be possible overnight. Wl keep chc to likely pops in the fcst
with lows mainly in the 60s with muggy conditions prevailing.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 337 PM EDT Friday...Sunday and Sunday night will feature
additional showers as upper level shortwave energy continues to
stream across the region ahead of an approaching surface low and
upper level trough as well. Temperatures will be close to
seasonal normals with highs in the mid to upper 70s and lows in
the lower to mid 60s. Have mentioned a slight chance for
thunderstorms in Northern New York on Sunday, but stability is
pretty limited.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 337 PM EDT Friday...More of the same weather is expected
for Monday through Tuesday as upper level trough very slowly
approaches our area and finally passes to our northeast later in
the day Tuesday. Will have additional scattered showers, and
possibility of thunderstorms on Tuesday afternoon. We will only
have upper level ridging over our region very briefly, Wednesday
and Wednesday night before upper level ridge slides eastward
and another upper level trough moves into our region. Wednesday
and Thursday should be pretty hot with upper ridge over the area
and then sliding east, highs will reach into the upper 80s in
the warmer parts of our forecast area each afternoon. Persistent
southwesterly upper level flow will lead to warm temperatures
through the period with chances of showers nearly everyday.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Through 00Z Sunday...A mix of VFR and MVFR conditions
prevailing this evening, with KMSS, KSLK, and KRUT all reporting
reduced visibility in smoke.
For tonight, the combination of increasing high clouds from
decaying convective complex north of Lake Ontario and increasing
low level jet of 15 to 25 knots, should limit fog potential.
Have IFR/LIFR at KMPV from 07z to 11Z, otherwise mostly VFR
overnight with local MVFR possible as smoke reduces visibility
to 3-5SM, especially 09z-13z Sat. Some areas of low level wind
shear possible near terrain features. On Saturday, low level
winds continue with localized gusts up to 25 knots likely at
KBTV/KMSS with developing showers/storms likely after 16z Sat,
mainly at NY terminals.
Outlook...
Saturday Night: VFR. Chance SHRA, Slight chance TSRA.
Sunday: Mainly MVFR, with local VFR possible. Chance SHRA, Slight
chance TSRA.
Sunday Night: Mainly MVFR, with areas IFR possible. Chance SHRA.
Monday: Mainly MVFR, with local IFR possible. Likely SHRA.
Monday Night: Mainly MVFR, with local IFR possible. Chance SHRA.
Independence Day: Mainly IFR, with areas MVFR possible. Likely
SHRA, Slight chance TSRA.
Tuesday Night: Mainly MVFR, with areas IFR possible. Chance SHRA.
Wednesday: Mainly VFR, with local IFR possible. Chance SHRA,
Slight chance TSRA.
&&
.HYDROLOGY...
Showers and thunderstorms are expected to develop on Saturday
with some storms capable of producing very heavy rainfall in a
short period of time. The highest probability of heavy rainfall
that could cause some localized/isolated flooding is currently
anticipated across northern NY on Saturday aftn/evening. The
primary threat would be ponding of water in urban areas, along
with the potential for isolated road/culvert washouts across the
complex terrain of northern New York. Basin wide rainfall
amounts between 0.50 and 1.50 inches is anticipated, with
localized amounts between 2 to 4 inches possible in the heavier
convection across northern New York. Additional showers and
thunderstorms with localized heavy rainfall is possible on
Sunday into early next week. The threat for localized flooding
will need to be monitor in the upcoming days ahead.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Hastings/Taber
SHORT TERM...Neiles
LONG TERM...Neiles
AVIATION...Hastings/Taber
HYDROLOGY...Taber
Area Forecast Discussion
National Weather Service Columbia SC
817 PM EDT Fri Jun 30 2023
.SYNOPSIS...
Expect hot and humid conditions through the holiday weekend,
with a slight chance of mainly afternoon and evening
thunderstorms. Temperatures are expected to gradually trend back
to near normal values by late next week, with a better chance
of scattered afternoon and evening thunderstorms.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
Convection has mostly dissipated this evening across the
forecast area, although with a tongue of instability remaining
over the eastern portion of the forecast area and the sea breeze
working inland along with some lingering surface boundaries,
cannot completely rule out an isolated storm in the eastern area
over the next couple of hours. Another mesoscale convective
system has developed this evening in southern KY and will rotate
around the upper ridge to our west. A system moved through
central Georgia earlier today which has stabilized much of the
state which along with newest hires model data gives confidence
that the latest MCS will remain to the west. Otherwise expect
passing high clouds overnight with low temperatures generally in
the low 70s.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Relatively little overall change in the pattern Saturday with
the upper high center remaining to our west, though it will nose
slightly east into our region as an upper trough shifts east
across the Central Plains. A weak surface trough will remain in
place at the surface. Main question involves what could be a
decaying MCS approaching from the NW Saturday morning, which
could possibly provide a focusing mechanism for convection later
in the day, along with possible associated residual mid/upper
convective debris cloud cover, which could work against max
diurnal insolation/heating. In any convection that develops,
there will be some risk of severe due to expected considerable
instability and high LFC height/low level inverted V feature in
forecast soundings. Latest guidance suggests generally mid to
upper 90s highs, with dewpoints in the lower 70s. Think NBM was
too high on afternoon dewpoints and trended it down closer to
MOS consensus. This brings max heat index projections up to near
105F, below our local Heat Index Advisory criteria of 110F.
The upper trough will shift east into the Midwest Sun/Sun nt,
suppressing the upper ridge but with little overall change to H5
heights/temps for our region. Positive H85 temp anomalies to
continue, with a slight increase in atmospheric moisture
progged. Chance to slight chance of diurnal convection. Will
have to monitor for possible Heat Advisory. Current heat index
projections for Sunday afternoon are up to 107F.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
May have to monitor Heat Index values again Monday. Otherwise,
an upper ridge will slowly build over the SW US/Four Corners
region and the main upper jet over the northern tier of States.
By late week, upper troughiness shifts into the Central
CONUS/Mississippi Valley region to the central Gulf Coast.
Slightly lower upper heights over our region, along with a
slight increase in atmospheric moisture, possibility of some
upper disturbances moving through at times, and a possible weak
surface boundary, suggest temps will gradually trend back to
near normal, with an increase in diurnal convective areal
coverage, during the period.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Convection remained west of all terminals and thunderstorms are
not in the forecast until Saturday afternoon. Some lingering
cumulus and cirrus overnight otherwise clear. Based on
persistence as well as smoke induced haze, kept MVFR
visibilities towards sunrise. HRRR smoke shows little
improvement in near-surface smoke, so cannot be certain in VFR
conditions tomorrow. Winds light overnight increasing to around
5 kt south southwest. Widely scattered thunderstorms and showers
possible mainly late afternoon.
EXTENDED AVIATION OUTLOOK...Brief restrictions are possible
through mid next week from passing showers and thunderstorms,
especially during the afternoon and evening hours. Early morning
haze and fog possible.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Cleveland OH
927 PM EDT Fri Jun 30 2023
.SYNOPSIS...
A cold front will enter the region from the northwest tonight,
remaining stationary across the state of Michigan through early
Sunday. This front will begin to cross the forecast area
eastward during the day Sunday. Multiple periods of showers and
thunderstorms are anticipated through the weekend along and
ahead of the cold front.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
Still dry across much of Ohio late this evening as a shortwave
pushes east across the Midwest. There continues to be a few
isolated thunderstorms found across Indiana, but a combination
of dry mid-level air and a lack of low-level flow appear to be
limiting the overall propagation and longevity of the storms.
Still looking like the best chance to see and showers and/or
storms tonight will be found along and south of the US-30
corridor.
Previous Discussion...An active near term period in store with
warm and humid conditions expected. A series of surface fronts
and upper level disturbances will cross the region this weekend
providing multiple opportunities for shower and thunderstorm
development. Continued warmth and muggy conditions with high
temperatures on Saturday in the mid to upper 80s and dew points
at or nearing 70 degrees. Overnight lows tonight and Saturday
night in the upper 60s to low 70s with no reprieve from humidity
as dewpoints overnight remain in the mid 60s.
Most hi-res guidance is hinting at a few isolated showers and
thunderstorms to develop across northwest Ohio late this evening as
a shortwave moves across the region tonight. More widespread shower
and thunderstorm development comes Saturday as a surface cold front
and accompanying upper level shortwave enter the lower Great Lakes
region. Hi-res models remain in disagreement with the ARW and FV3
the most ambitious and HRRR the most lack luster in regards to
coverage and intensity of thunderstorm development. Regardless, the
SPC has placed our entire area in a SWODY2 Marginal Risk (1/5) for
severe storms with primary hazards of strong winds and hail. In
addition to a severe weather threat, there is a risk for training
storms to lead to areas of flash flooding on Saturday. Multiple
elements at play in regards to flooding potential as model soundings
indicate skinny CAPE, a deep warm layer greater than 10,000 ft,
moist low/mid levels, and PWATs nearing 2+ inches. As such, the WPC
has put the bulk of our forecast area in a Slight Risk (2/4) in
their Day 2 Excessive Rainfall Outlook.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Busy weather will continue through the short term period as a cold
frontal boundary very slowly sags southward through the region. This
will bring widespread showers and thunderstorms Sunday with locally
heavy rainfall, but uncertainty regarding the convective evolution
Saturday and Saturday night and how those leftover outflow
boundaries and cloud cover may influence what redevelops Sunday
makes this a tricky forecast. It will definitely rain Sunday, but
the extent of heavier thunderstorms and where those will set up
remains uncertain.
Looking at the details, a mid/upper shortwave trough will eject from
the mid Mississippi Valley Sunday morning into the eastern Great
Lakes by Monday afternoon. As this occurs, some jet coupling between
two seasonably strong 50-60 knot H3 jet streaks will allow a weak
surface low to strengthen a bit as it moves ENE along the sagging
cold frontal boundary. Guidance is in decent agreement on this
surface low tracking across northern Ohio or Lake Erie Sunday
evening into Sunday night, with strongly diffluent flow ahead of it
combined with the jet coupling leading to abundant forcing for
ascent. This upper forcing will generate a decent 20-25 knot low-
level jet which will support strong warm/moist advection into the
frontal boundary as the surface low passes through. This all spells
widespread showers and thunderstorms if cloud cover and early day
outflow does not inhibit all of the instability. At this point, at
least moderate MLCAPE values of 1000-1500 J/Kg are feasible, and
this combined with PWATS of 1.75 to 2 inches, deep warm cloud layer
depths, skinny CAPE profiles, and 850-300 mb flow aligned parallel
to the frontal boundary all support at least a few bands/cluster of
more organized thunderstorms. The flow aligned parallel to the
boundary could allow these to train, so flash flooding is the
biggest concern for Sunday afternoon into Sunday night. Due to the
above mentioned uncertainty regarding early day clouds/outflow, we
just cannot say at this point what areas will see the most organized
storms and how widespread/organized they will become, but what is
certain is that at least some swaths of locally heavy rainfall will
occur, with all areas seeing at least some rain through the day. The
very warm, moist profiles will limit the extent of any severe
weather potential, but decent deep layer shear around 30 knots could
aid in a few wet microbursts, particularly if these instability ends
up a little higher. Southern areas near and south of US 30 remain in
a SWODY3 marginal risk which is reasonable.
Coverage of showers/storms will gradually decrease Sunday night as
the surface low and better forcing move east, but the front will be
very slow to push south and east, so another flare up in scattered
convection is possible Monday afternoon, particularly over far
eastern Ohio and western PA, so kept likely PoPs there Monday with
chance elsewhere. The forcing is much less pronounced Monday, and
this combined with a lot of cloud debris and outflow will likely
keep things lighter and less organized compared to Sunday. Weak
surface high pressure and mid/upper shortwave ridging building in
Monday night will bring drier conditions, but still kept slight
chances for a few lingering showers in far eastern Ohio and NW PA as
the boundary lingers nearby.
Highs will generally range from the upper 70s to low 80s Sunday and
Monday, but it will be muggy with dew points in the upper 60s to low
70s Sunday and only slightly better (mid/upper 60s) Monday. Lows
Sunday night and Monday night will stay in the mid/upper 60s.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
The pattern is looking seasonably warm and humid in the extended as
quasi-zonal flow Tuesday gives way to amplifying mid/upper ridging
over the eastern CONUS Wednesday and Thursday ahead of broad
northern stream troughing digging into the northern Rockies and
northern Plains. Surface high pressure centered near the
Appalachians Tuesday will move to the east coast by Wednesday and
Thursday setting up broad southerly flow. This will allow the old
frontal boundary in the Ohio Valley to creep back northward for mid
week bringing the higher dew points and warmer temps back. There
will be widely scattered convection each afternoon Tuesday and
Wednesday, but nothing organized due to limited forcing and likely
capping developing in the mid levels. By late Thursday and Friday,
the aforementioned northern stream mid/upper trough will begin to
encroach on the western Great Lakes leading to gradual height falls
as the cold front sags toward the region. This will support
gradually increasing chances for convection late Thursday into
Friday, but timing of the frontal passage is uncertain at this point.
Highs will generally range from the mid to upper 80s Tuesday
through Thursday cooling into the upper 70s to near 80 Friday.
&&
.AVIATION /00Z Saturday THROUGH Wednesday/...
VFR across the TAF sites this evening with primarily VFR to
persist through the TAF period. The main challenge with this TAF
package is to pinpoint any showers and/or thunderstorms that may
impact the terminals. However, at this time, confidence is too
low to include anything other than vcsh/vcts at the TAF sites.
There may be an uptick in activity tonight into Saturday
morning, although the location and timing remains uncertain.
Winds are expected to remain light outside of any thunderstorms
through the TAF period, 10 knots or less and generally out of
the south to southwest.
Outlook...Non-VFR possible in scattered to widespread showers
and thunderstorms Saturday through Monday. Showers and
thunderstorms will be most numerous Sunday afternoon and
evening. Non-VFR may return again in isolated to scattered
showers and thunderstorms on Tuesday and Wednesday afternoon.
&&
.MARINE...
Quiet marine conditions are expected through early next week as a
weak frontal boundary gradually pushes southward Saturday through
Monday. Generally S to SW winds of 5-10 knots are expected tonight
into Sunday becoming NNW at 10-15 knots Sunday night and WNW at 10-
15 knots Monday. Generally light SW winds of 5-10 knots are then
expected Monday night through Wednesday as the boundary pushes south
of the area and weak high pressure builds in.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Iverson
NEAR TERM...Iverson/Kahn
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...Kahn
MARINE...Garuckas
Area Forecast Discussion
National Weather Service Quad Cities IA IL
659 PM CDT Fri Jun 30 2023
...00z AVIATION UPDATE...
.SHORT TERM...(This evening through Saturday)
Issued at 152 PM CDT Fri Jun 30 2023
Key messages:
1. Fog could redevelop across the area tonight.
2. Chances for thunderstorms late overnight and through the day
tomorrow, with most of the area south of I-80 under some severe
weather threat level.
Discussion:
This afternoon, high clouds associated with an exiting
thunderstorm complex kept the area cooler and quiet. A soak rain
was found south of I-80 where radar had estimated around a quarter
inch of rain this am along I-80 and a little over an inch in far
southeast Iowa. Temperatures in the 70s could warm a few more
degrees, but moist airmass leads to sticky conditions across the
area. The largescale pattern remains unchanged with our area in
`the ring of fire` through the period. Main questions are how
dense does the fog get tonight and when is the next chance for
storms and will any be severe?
Looking towards fog, similar setup to this morning, plentiful BL
moisture with a fresh fallen rain. High clouds are breaking out
west of the area and there subtle boundary across the area. CAMs
are aggressive with us going to dense fog again tonight. Did not
want to jump on that train just yet, but did introduce patchy fog
and areas of fog across the area. Later shifts may need to issue a
DFA especially if vsbys start to drop after sunset.
As far as storm potential, CAMs in good agreement with several
rounds of showers and storms across the Highway 34 corridor
starting tonight thru Saturday, before a cold front moves through
the area tomorrow. Showers and storms along the front will spread
north as the wraparound precip zone takes its slow time to move
across the northern CWA through the day Saturday and into the
evening hours as well. Some CAMs have a MCS roll across southern
areas this evening. The NAMnest is the most aggressive and has
this moving through the area around 10 PM. If this is going to
occur, expect the line of showers just west of EAX to light up in
the next 6 hours or so. The area does seem to have good
instability and decent shear. I`m not confident on severe threat
or northern extent, but we will need to keep an eye on this for
later shifts. HRRR suggests only the far south could see
potentially severe storms and that the NAMnest is little overly
aggressive as far as northern reach goes.
Tomorrow, instability becomes a question as better shear moves in.
This means updrafts may become better organized and have a better
chance at living longer. Instability is less than impressive, but
an always concerned that shear will overcome lesser instability.
We could see severe storms further north than the slight,
especially if the shear is used effectively. If there would be
severe storms, my thought is that low-end wind gusts and hail
would be possible.
.LONG TERM...(Saturday night through Friday)
Issued at 152 PM CDT Fri Jun 30 2023
Key Messages
1. Active "ring of fire" pattern expected through the period to
bring near daily chances for storms.
2. Strong storm system track will be north of the area.
3. 4th of July looks hot with highs in the upper 80s to low 90s and
we could see thunderstorms, but forecast confidence is low at this
time.
Discussion:
Ridging sneaks into the area to start the period as cooler H85 temps
move into the area for the weekend. These cooler temps will be short
lived before warmer temps move into the area to start the work
week. Ridging begins to break down by the 4th as a more zonal flow
leads to a more active storm track. By the end of the week, much
cooler H85 temps are forecast to be in the area. Temperatures late
next week could be well below normal. With large spread in the
models confidence in how cool temps could be is low at this time,
and we have a lot of potential for storms between now and then.
Severe risk looks to be low to non-existent to start Sunday as weak
shear will limit updraft organization. With extensive cloud cover,
temperatures will be lower and thus instability should not be
impressive. A short lull in the activity is expected for Monday
into possible Tuesday overnight.
The 4th of July currently looks dry for most of the area. Current
timing on the ridge will keep the area quiet, however there is a
front and wave moving into the area later on the 4th. Any timing
differences could lead to a chance for precip for the area. At the
current time, we will see instability build and some deep layer shear.
Capping may keep the area quiet. We will need to keep an eye on
this as we go through the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 650 PM CDT Fri Jun 30 2023
A VFR evening with just passing high clouds and an isolated shower
possible, but then light and variable sfc wind field with high
DPTs may foster areas of MVFR to IFR fog into early Sat morning.
Even some LIFR fog possible. Isolated to sctrd showers and
thunderstorms will look to then spread in from the southwest
mainly after midnight and along/south of the I80 corridor into
Sat morning. Some strong storms with variable wind gusts possible
in the VCNTY of BRL after 07z/2 AM CDT, as well as lowered CIGs
and visibility from passing heavy rainfall with the stronger
storm cells. Some improvement from the fog and precip by mid Sat
morning south of I80, with isolated showers/storms lingering north
of I80 into early afternoon. Late in the TAF period, some
stronger storms possible again after 3-5 PM Sat especially south
of I80.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SHORT TERM...Gibbs
LONG TERM...Gibbs
AVIATION...12
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1029 PM EDT Fri Jun 30 2023
.SYNOPSIS...
Hot and humid conditions are in store Saturday and Sunday, with
chances for pop-up thunderstorms in the afternoons, but also
the possibility of organized storms pushing in from the north or
west overnight. A weak front Sunday night will provide a bit of
relief from the heat, though temperatures will remain seasonably
muggy. Chances for showers and thunderstorms will continue through
the week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1030 PM Friday: Made a few minor tweaks to hourly temps
through tonight as they were already cooling off quicker than
anticipated. Otherwise, the fcst remains on track.
The synoptic pattern will remain similar as it has the past few days
with a conveyer belt like feature wedged between an upper high
across the southern CONUS and an upper low churning over Canada.
This feature should start to breakdown toward the end of this
forecast period. The next focus will be on a second MCS currently
tracking SE across the TN Valley. The Day 1 SPC Marginal risk for
severe thunderstorms through tonight was trimmed back to the mainly
the mountain zones. Model guidance from the CAMs have struggled to
pinpoint convection, especially in regards to timing, for the CWA.
Latest CAM runs from the HRRR show the MCS pushing into the the NC
Mountains during the overnight hours, while the NAMNest has the
complex pushing into the NC Mountains shortly after daybreak
Saturday. If this convection holds together as it pushes SE, the
main potential concerns will be damaging winds and hail. The timing
and exact track of the MCS is subject to change and confidence on
this system is low, given the uncertainty shown in the CAMs. Lows
tonight should be around 5-7 degrees above climo.
Higher pressure aloft and at the surface will continue to build into
the western Carolinas raising another concern for the holiday
weekend: hot temperatures. As moisture continues to linger,
dewpoints will remain in the 70s, allowing heat indices to reach the
triple digits across portions of NE GA and the western SC Upstate.
Heat indices from 100-104 degrees are possible for these locations,
but should remain just below criteria for a Heat Advisory, which
starts at 105 degrees. However, these heat indices will depend
heavily on the timing of convection earlier in the morning as well
as another round of convection Saturday afternoon and evening. The
SPC Day 2 Severe Wx Outlook has a Slight Risk for severe
thunderstorms across much of NE GA, much of western NC, and then
northern SC Upstate. A Marginal risk for severe thunderstorms is
noted elsewhere. Main impacts with any storms that become severe are
damaging wind gusts and hail. Highs on Saturday will be around 3-6
degrees above climo.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of midday Friday: Upper ridge tilts late Saturday and axis moves
over the Carolinas in advance of a synoptic scale shortwave entering
the mid-Mississippi Valley. Thus the MCS track may be reoriented such
that any complex developing Saturday night would track across the
WV/VA mountains and could miss us to the east, or at least affect
mainly the I-77 corridor. However, either way, still too close for
comfort given the propensity for model error in such a setup, as well
as the fact we will be coming off an afternoon with abnormally high
CAPE but little in the way of a convective trigger. Enter the GFS,
which doesn`t distinctly depict such an MCS, but does depict
warm-sector activity invof the southern Appalachians Saturday night,
preceding the Mississippi Valley low.
Convective chances Sunday afternoon as well as potential heat index
impacts both will be at the mercy of sfc dewpoints. As usual in these
sort of events that depends on how much mixing models resolve, and
perhaps on how wet soils are following rainfall; the uncertainty
surrounding MCSs again comes into play. The NAM is considerably
higher with dewpoints, probably being too high in the mid 70s. With
resultantly lower LCLs it produces close to 5000 J/kg SBCAPE Sunday
aftn over portions of the CWA, which would be in the top 10 all-time
observed values at our RAOB sites. Concurrently the GFS produces only
1000-1500, although it may be taking into account too much mixing.
Coverage during peak heating may remain limited due to warm midlevels
inhibiting free convection and lack of a good trigger. GFS and NAM
both depict much better coverage in the evening as cold front
approaches and taps into the strong instability west of the
mountains, and/or as prefrontal trough overcomes the cap in our CWA.
Effective shear of 20-30 kt could result in multicell clusters, and
suggests TN activity could survive into the NC mountains. With PWAT
values in the 75-90th percentile and slow MBE vectors, some threat of
flash flooding is possible with such storms. Regarding the afternoon
heat indices, currently we expect values will peak right around 105
in the urban heat island of the Charlotte metro as well as in the
southern Lakelands. Given the fcst range and somewhat limited
confidence anyway, not yet ready to issue an advisory.
The shortwave will pass by to our north Monday. The actual cold front
looks to enter the CWA during the day, making drier air available
aloft and thus a more effective diurnal dip in dewpoints, along with
very slightly cooler temps for the NW half of the area. Together
these changes will be subtle but should be enough to keep heat index
out of advisory range. Convection looks to focus within trough east
of the Appalachians, but some ridgetop initiation certainly will be
possible. For now, the whole CWA is in chance range PoPs, but if
post-frontal drying and/or subsidence inversion trend stronger, PoPs
could easily trend lower for the mountains at least.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 200 PM Friday: With the Monday shortwave helping to suppress
the Southeast ridge, a quasi-zonal pattern appears in store for most
of next week. Cold front appears likely to stall between the I-20 and
I-40 corridors Tuesday, then perhaps being reactivated ahead of a
shortwave moving into the mid-MS/lower OH valleys Tue night or Wed.
That feature appears likely to reach our CWA by Wednesday afternoon.
Height falls with the shortwave should be reinforced by a larger
scale trough moving thru the Central US in the latter half of the
week.
Altogether this should result in an unsettled, enhanced diurnal
pattern across the region for the bulk of the week. Certainly can`t
say July 4th will go off without any weather impact, although that
day currently looks to be the least stormy of the medium range period
(though with higher coverage than Monday). Peak afternoon PoPs will
be generally chance for the Piedmont and likely for the mountains.
Weakly sheared but profiles point to pulse storms, although depth of
moisture may keep damaging wind threat a little lower than typical,
though that means the locally heavy/excessive rainfall threat will be
greater than usual. Max temps will trend cooler as the troughing
develops, but with mins elevated by convective debris and/or muggy
dewpoints. Heat index concerns are currently not expected any day in
the period.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Should remain VFR through the period outside
of mountain valley fog overnight into daybreak Saturday as well as
SHRA/TSRA chances early Saturday morning into Saturday evening. Have
MVFR fog developing at KAVL and KHKY overnight as patchy may develop
before lifting around sunrise Saturday morning. Also have MVFR cigs
at KAVL near daybreak Saturday as low clouds may develop across the
NC mtns. Winds this evening into tonight will be mainly light with a
S`ly component east of the mtns, and a N`ly component at KAVL. Winds
look to become calm to light and variable overnight into early
Saturday morning. Winds east of the mtns should become mainly WSW/SW
mid-morning Saturday into early Saturday afternoon. Winds east of
the mtns then turn more S`ly late Saturday afternoon into early
Saturday evening. Winds at KAVL will remain NW`ly through early
Saturday afternoon and have the potential to turn SW`ly late
Saturday afternoon. However, confidence on this is low, thus
maintained a NW wind at KAVL Saturday afternoon and early evening.
Confidence on showers and thunderstorms will be low through the 00Z
TAF fcst period as high-res guidance is not in agreement on the
timing of activity early Saturday morning into Saturday evening.
Have PROB30s for SHRA/TSRA at all terminals Saturday afternoon and
evening, with the exception of KAND. KAND has the lowest potential
to see activity during the 00Z TAF fcst period, so only have VCTS at
the terminal for now.
Outlook: A more typical summer pattern returns on Sunday before a
cold front tracks across the region early next week keeping shower
and thunderstorm chances around.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...Wimberley
NEAR TERM...AR/CP
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...AR
Area Forecast Discussion
National Weather Service Huntsville AL
829 PM CDT Fri Jun 30 2023
...New NEAR TERM...
.NEAR TERM...
(Tonight)
Issued at 829 PM CDT Fri Jun 30 2023
Severe MCS over middle TN is pushing a gust front/outflow
southwest of the parent updrafts and may reach our southern TN
counties within the hour with gusty winds. The question is whether
the parent storms are able to reach reach our area or if
additional storms are able to develop along said outflow. The 00Z
sounding just came in for BMX with a hefty MU CAPE of 4800 j/kg
and steep low and mid level lapse rates. For now, have added a
low PoP for the area, mainly for southern TN and northeast AL. The
latest HRRR runs have been flip-flopping a bit on whether
activity makes into HUN forecast area. Course of least regret is
to add the low PoP and remove later if this misses us or falls
apart. Temperatures are dipping back into the middle 80s (rural
areas) to around 90 (heat island metros) as of 01Z with dew points
in the 70s to around 80. So the sultry air has arrived.
&&
.SHORT TERM...
(Saturday through Monday)
Issued at 216 PM CDT Fri Jun 30 2023
The heat/humidity will continue across the region on Saturday with
highs in the mid to perhaps upper 90s and dewpoints in the 70s.
This will create heat index values over 105 degrees across the
entire area, and potentially above 110 degrees for areas along and
west of I-65. A Heat Advisory will be in effect for northeast
Alabama and Franklin County, TN, while an Excessive Heat Warning
will be in effect for the HSV, DCU, MSL metro and the I-65
corridor of north Alabama. We will likely have some better chances
for showers and thunderstorms during the afternoon/evening hours
on Saturday as the ridge begins to weaken to our north and a
shortwave ripples SE/ESE from the Ohio Valley into the Southern
Appalachians. Have added a 40% of thunderstorms for Saturday
afternoon/evening. These may be diurnally driven pulse convection
during the afternoon/evening or part of an MCS that clips portions
of the Tennessee Valley during the late afternoon/early evening
hours. This is a low confidence forecast as some guidance favors a
later start and does not move convection into the area until the
overnight period. Should this occur adjustments to the forecast
will be needed.
An additional Heat Advisory may be needed on Sunday due to another
hot/humid day with heat indices in excess of 105 degrees over at
least portions of the region. The ridge will gradually begin to
deamplify early next week and subsequently this may place us in a
more favorable location for convection, especially by Monday as
our storms chances rise from 30-40% on Sunday to 50-60% on Monday.
We`ll also begin to get a break from the dangerous heat by Monday
with highs in the low to mid 90s and peak heat indices closer to
100 degrees.
&&
.LONG TERM...
(Monday night through Friday)
Issued at 216 PM CDT Fri Jun 30 2023
With the ridge flattening early to mid next week, we`ll enter more
zonal flow with slightly cooler temperatures (lower 90s highs) and
better daily chances for showers and thunderstorms thanks to some
passing shortwaves and a stalled boundary somewhere across or near
the Tennessee Valley. The latest round of NBM guidance favors
medium chances for storms Tuesday (4th of July), Wednesday, and
Thursday, with PoPs at 60-70% each day. Those with outdoor plans
this Holiday week should be ready for the daily thunderstorms each
day and have a way to get weather information.
&&
.AVIATION...
(00Z TAFS)
Issued at 452 PM CDT Fri Jun 30 2023
VFR flight weather conditions are expected. Isolated to scattered
SHRA and TSRA may develop after 18Z/01, but the probability is too
low to include at either KMSL or KHSV at this time. Future updates
may include this in the forecast as this becomes more clear.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Excessive Heat Warning until 8 PM CDT Saturday for ALZ001>007-
016.
Heat Advisory until 8 PM CDT Saturday for ALZ008>010.
TN...Excessive Heat Warning until 8 PM CDT Saturday for TNZ076-096.
Heat Advisory until 8 PM CDT Saturday for TNZ097.
&&
$$
NEAR TERM...17
SHORT TERM....AMP
LONG TERM....AMP
AVIATION...17
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
745 PM CDT Fri Jun 30 2023
.SYNOPSIS...
Issued at 745 PM CDT Fri Jun 30 2023
An active weather pattern will persist across Illinois through
the holiday weekend, and bring daily chances for thunderstorms
through Sunday evening to central and southeast Illinois. Strong
to severe storms are possible each day through Sunday, so stay
weather aware through this weekend. Muggy lows overnight in the
upper 60s to near 70. Very warm and humid conditions will prevail
again on Saturday with highs in the mid to upper 80s in central
Illinois, and lower 90s in southeast Illinois. Heat indices could
peak at or above 100 degrees in southeast Illinois again on
Saturday afternoon.
&&
.UPDATE...
Issued at 745 PM CDT Fri Jun 30 2023
Thunderstorms have been developing over the last few hours along
the residual boundary from the earlier activity, in an arc from
near Kansas City into western Kentucky. This has been along a
tight CAPE gradient with SPC mesoanalysis at 7 pm showing a peak
over 5000 J/kg. CAPE trends off the RAP show the axis of higher
values shifting into southern Illinois. There are two things to
focus on for tonight:
1) Heavy rain -- WPC mesoscale analysis showing potential for
rainfall rates of 1.5 to 2 inches per hour in areas south of I-70,
where there was an axis of 2-4 inch rain totals yesterday across
parts of Clay, Richland and Lawrence Counties. Precipitable water
values near 1.8 inches will lead to some heavy rain amounts once
again and flooding will be a concern in these areas.
2) Severe potential -- Latest run of the HRRR has been focused
more on the south half of the forecast area prior to midnight, and
placement of the current cells to the most recent run appears
reasonable. Supercell currently exiting the St. Louis metro should
track more along the I-64 corridor and stay just to our south, but
the west-east axis over Missouri will be more of a player late
evening and overnight. Latest RAP/HRRR trend would suggest more
of a northward trend late in the night as the boundary/effective
front begins to lift a bit north.
Rain trends have been updated for this evening, with a drier trend
near/north of I-74 until after midnight.
Geelhart
&&
.SHORT TERM... (Through Late Saturday Night)
Issued at 300 PM CDT Fri Jun 30 2023
A weakening MCS/MCV over northern IL had a few showers and
isolated thunderstorms ne of I-74 and tracking eastward into west
central and nw Indiana. Outflow boundary from this system was over
central MO into southern IL and sw KY and much more unstable
airmass there where MLCapes are 3000-4500 j/kg south of CWA and
lower to 500-1000 j/kg over northern CWA where convection moved
through since late morning. Tropical airmass remains in place over
central/southern IL with PW values of 1.6-1.9 inches, highest in
southern/sw IL. Temps currently were in the lower 80s over much of
central IL with Lacon at 77F, while mid to upper 80s in southeast
IL with Flora and Lawrenceville 88-89F and heat index of 100F.
Heat Indices were 105-115F from St Louis to Evansville where heat
advisory in effect.
Convection to develop near outflow boundary sw of CWA late this
afternoon and into this evening, and some of this convection could
affect our far sw CWA from Jacksonville to Effingham south. SPC
has slight risk of severe storms from Canton to Lincoln to Paris
south with a 15% or greater risk of damaging winds and large hail.
Areas from Litchfield to Effingham to Lawrenceville south have 10%
risk of wind gusts of 65 kts/75 mph or higher. The 15% risk of 2
inch or larger hail is just sw of our CWA over sw/southern IL.
CAMs still have varying solutions with evolution of convection
tonight over central/se IL, but consensus is more development of
convection during this evening into central IL and early overnight
and diminishing later tonight with stronger storms over
southern/sw CWA. WPC has marginal risk of excessive rainfall over
central and southern IL tonight with this convective complex.
Muggy lows overnight in the upper 60s and lower 70s.
Should be a lull in convection Sat morning before airmass
destabilizes with daytime heating and ahead of a short wave/MCS
developing and tracking eastward into central MO Sat afternoon.
This MCS will likely bring more thunderstorms into central/se IL
during mid/late Sat afternoon and Sat evening and more severe wx
possible. SPC Day2 has extended enhanced risk of severe storms
northward to a Rushville to Bloomington line with slight risk as
far north as Canton to Peoria to Pontiac. There is a 30% risk of
damaging winds in the enhanced risk area with 10% or greater
probability of wind gusts 65 kts/75 mph or greater. Highs Sat
range from mid 80s northern CWA to lower 90s in southeast IL where
heat indices peak around or just above 100F Sat afternoon from
I-70 south. PW values will be quite high on Saturday and Sat
evening and WPC has slight chance of excessive rainfall over much
of central and southern IL Sat afternoon into Sat night with 1-3
inches of rainfall possible.
07
&&
.LONG TERM... (Sunday through Next Friday)
Issued at 315 PM CDT Fri Jun 30 2023
Short wave trof to shift eastward over IL on Sunday and likely
bring more showers and thunderstorms. More unstable air mass
shifts to the se, and SPC Day3 outlook has slight risk of severe
storms south of I-72 Sunday afternoon and early Sunday evening
until sunset. WPC has marginal risk of excessive rainfall from
Wabash river se on Sunday afternoon/evening. Not as hot Sunday
with highs in the lower 80s over central IL and mid 80s in
southeast IL with upper 80s from highway 50 south.
Quieter wx finally appear to return to CWA after sunset Sunday
night and Monday as upper level trof passes into the eastern parts
of the Great Lakes and Ohio river valley. Isolated showers and
thunderstorms could develop Mon afternoon as dewpoints still in
the mid to upper 60s. Seasonable highs Monday in the mid to upper
80s. Fair weather expected after sunset Monday into early Tue
morning, then have 20-30% chance of convection Tue mainly Tue
afternoon and early Tue evening before sunset. A cold front
pushing south/sw into the Midwest during mid week to approach nw
IL by sunset Wed and move se through central IL during Wed night
and in southeast IL early Thu morning. This will bring a better
chance of showers/thunderstorms from Wed afternoon into Thu. Very
warm and humid Tue/Wed with highs in the upper 80s to around 90F.
Temps trending cooler behind cold front Thu/Fri with highs in
upper 70s/lower 80s by next Fri.
07
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 625 PM CDT Fri Jun 30 2023
Main aviation concern will be with timing of convection. An arc of
developing storms from near KMCI-KSTL will make some progress
toward central Illinois toward 05-06Z. Impacts at the TAF sites
appear be most likely 06-09Z, with some brief visibility drops to
MVFR or IFR in the heavier showers. Showers will linger at times
into late morning, with more substantial thunderstorm chances
toward the end of the forecast period.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1031 PM EDT Fri Jun 30 2023
.UPDATE...
Issued at 1031 PM EDT FRI JUN 30 2023
The evening update is out. Blended the latest 1-hr NBM and
CONShort model for PoPs, which is lowering PoPs for the overnight
but raising PoPs through the late morning into early afternoon
period. This would appear to make sense as a low-amplitude upper
ridge axis is progged by models to move east of the forecast area
tonight, allowing for mean northwesterly flow aloft to become more
westerly. This would better support upstream convective activity
making it to our area from the west by Saturday morning or
afternoon. No other significant changes were made to the forecast
with this update.
UPDATE Issued at 735 PM EDT FRI JUN 30 2023
Isolated supercell thunderstorms have developed over south-central
Kentucky over the last few hours within a very unstable
atmosphere. This activity may in part have formed from a leftover
boundary from this morning`s thunderstorm activity. Will continue
to monitor trends and update the forecast accordingly through the
evening. The main change with this update was a to raise PoPs
slightly for this evening in the far southwestern portion of the
forecast area.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 529 PM EDT FRI JUN 30 2023
Morning convection left a rain cooled surface layer. Warm, moist
advection over this layer kept a deck of low clouds in place
through most of the day. This in turn held temperatures back from
where they otherwise would have been, which limited
destabilization and ensured that we stayed dry up to the present.
The dry weather should last into the evening, but the forecast
then becomes problematic once again. Models agree that we will
remain on the periphery of a subtropical ridge over the Gulf
Coast, in an area with potential for MCS occurrence. The ridge
will flatten by the end of the short term period as an upper level
trough approaches. It is the details which create problems.
Models disagree on tonight`s outcome, with cascading effects for
the rest of the short term period. Extreme instability is present
over the mid Mississippi Valley this evening, and convection is
just beginning to initiate there. The outcome of this activity,
particularly the evolution and decay of the MCS that develops,
will be important for our weather. The GFS and HRRR show it moving
through all of the JKL forecast area overnight in a weakening
phase. The NAM is slower and largely further north. Following
this, the NAM allows for more instability during the day Saturday
compared to the GFS. Additional model differences also evolve
upstream. The bottom line-- a model blend yields a chance POP
returning to the forecast overnight, with a very broadbrushed
forecast for Saturday and Saturday night, once again with chance
POPs.
Temperatures on Saturday will depend on precip and clouds. The
current blended forecast has enough heating combined with high dew
points to give heat indices topping out mostly in the 95-105
range. It is possible that some places could reach heat advisory
criteria (the southwest has the best chance), but confidence is
not currently high enough for an NPW.
.LONG TERM...(Sunday through Friday)
Issued at 342 PM EDT FRI JUN 30 2023
Key Messages:
-Storms could be strong to severe Sunday.
-A break in the active weather is possible by Monday and Tuesday.
-More active weather returns to end the period.
Overall Pattern:
A positively tilted trough will push east into the western Great
Lakes and Ohio Valley to begin the period. A low-pressure system
will develop at the surface, followed by a trailing cold front.
This will progress east on Sunday and help to develop showers and
thunderstorms in the afternoon and evening. On Monday, this trough
flattens out and pushes off to the east toward the Mid-Atlantic
states, and high pressure progresses east. The heights will build
on Tuesday, and the surface high pressure will build eastward too.
By mid- to late-week, the guidance becomes more uncertain and
possibly more active once again as additional shortwave energy
rides the somewhat flattened flow aloft. However, there are
varying scenarios and timing on features by late in the week.
Sunday
A mid-level trough pushes into the Ohio Valley with low pressure
and a trailing cold front. The ensemble systems show decent
agreement on height falls associated with this trough axis. This
will ignite showers and thunderstorms throughout the day, peaking
in the afternoon and evening hours. The ample instability coupled
with effective shear around 30-40 knots would lead to the
potential for some strong to severe storms. SPC does have us
sitting in a Slight Risk or 2 out of 5 Level for severe weather,
and for now that seems reasonable. The main threat would be
damaging wind gusts. The NBM has been struggling with going a bit
on the high side for afternoon maximum temperatures, as we have
underachieved due to cloud cover recently. This makes one want to
lean toward the lower end of the NBM guidance to account for
Sunday, as we could have increased cloud cover and convection
across the area.
Monday into Tuesday
This trough pushes east Monday, and we will see at least some
potential for afternoon and evening showers and thunderstorms in
the far east and northeast portions of the state. The ensembles
and deterministic data are showing signs of height rises by
Tuesday, and this could actually help mitigate showers and
thunderstorms. Even so, we could still see around 20-30 percent
chances of rain, mainly in the afternoon hours, with more limited
instability and moisture noted in the ensemble systems. The PoP
was adjusted down from the NBM PPI, which was too high for more
diurnally driven convection. Afternoon highs Monday will be closer
to normal (JKL 85 and LOZ 86) and perhaps slightly above normal
on Tuesday, with the potential for more sun and fewer convective
influences.
Wednesday through Friday
Another period of active weather is possible by the end of next
week, as the ensemble systems indicate increased moisture and
lowering heights. However, there are some differences in the
timing and location of these shortwaves that will help increase
the PoP chances. Right now, if pinned down, I would agree with the
NBM in bringing the best chances of PoPs (around 70 percent) on
Friday. Overall afternoon highs stay near normal Wednesday and
Thursday, but maybe somewhat below Friday given the higher PoP
chances and subsequent cloud cover.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 740 PM EDT FRI JUN 30 2023
Main challenges for the TAF period are with fog formation as well
as for the potential for one or more rounds of thunderstorms to
move across the forecast area. Given low confidence in timing of
convective activity we elected to mainly use VCTS in the TAFs
fairly broadly, but TEMPO groups were added for gusty winds and
TSRA overnight given somewhat decent model agreement with the
timing a convective system moving across central and southwest
parts of the forecast area. However, it should be stressed this is
lower than usual confidence for a TEMPO group. With potential fog
formation and with shower/thunderstorm activity VFR/MVFR
conditions may deteriorate to IFR or lower.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CMC
SHORT TERM...HAL
LONG TERM...DJ
AVIATION...CMC
...UPDATED AVIATION FORECAST DISCUSSION...
.SYNOPSIS...
Issued at 237 PM CDT Fri Jun 30 2023
Key Messages:
- Multiple rounds of showers and thunderstorms are expected this
evening through late Saturday afternoon. Heavy rainfall is the
main threat, however, strong to briefly severe thunderstorms
cannot be ruled out for areas across far southwest Nebraska.
- Dry and warming conditions return for a brief period on Sunday
and Monday ahead of another potentially wet and active period
beginning late Monday through the latter end of the week.
Recent GOES-16 WV and RAP 500-mb analysis showed a positively tilted
trough extending from Wyoming into Arizona, moving eastward from the
central Rockies and approaching the Nebraska Panhandle. Further
northeast of this feature, an upper-level trough of low pressure was
centered across Ontario, extending across the Upper Midwest and
Great Lakes region. Broad upper-level high pressure was anchored
across the Gulf Coast area. All of these features combined has
resulted in southwesterly flow aloft across western and north
central Nebraska. At the surface, an area of low pressure was noted
across eastern Kansas with a stationary front draped southwest
across Kansas to another surface low centered across the Oklahoma
Panhandle. As of 2PM CT, temperatures ranged from 72 degrees at
Gordon to 77 degrees at O`Neill. Scattered rain showers with some
embedded thunder gradually tracked northeast across portions of
southwest into north central Nebraska this morning into the early
afternoon. Drier air pushed in behind this early activity resulting
in the showers dissipating rather quickly ahead of the main round of
precipitation, currently developing across far northeast Colorado
into portions of the Panhandle and southwest Nebraska
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 237 PM CDT Fri Jun 30 2023
This evening and tonight...The aforementioned upper-level trough
continues it`s eastward progression, becoming overhead later
tonight. The ongoing activity will push further northeastward
encompassing much of western and north central Nebraska this evening
and tonight. In regards to the severe potential, the best heating
and forcing appears to remain across northeastern Colorado into
Kansas. The environment today is less favorable for severe
weather as compared to the last few days across the area. However,
portions of far southwest Nebraska does have increased 0-6km Bulk
Shear of 30 to 45kts. Which combined with MLCAPE values of ~600
J/kg and lapse rates of 6-6.5 C/km, may be sufficient enough to
support strong to briefly severe thunderstorms. Though widespread
severe weather is not anticipated, heavy rainfall is the primary
concern with this activity. Plentiful low-level moisture combined
with PWAT values of 1 to 1.25 inches will support an environment
capable of significant rainfall rates, especially for areas across
southwest and south central Nebraska. Recent rainfall over the
last few nights has resulted in saturated ground across much of
the area which will lead to increased flooding concerns. Another
area with increased concern for flooding across the South Platte
River where high flows have been observed this past week. This
heavy rainfall threat is highlight by the WPC Excessive Rainfall
Outlook of a Slight Risk for areas generally south of Highway 2.
Total QPF values are forecast to range from a few tenths of an
inch across the Sandhills to an inch or greater across southwest
and south central Nebraska with locally heavier amounts possible.
Saturday and Saturday night...The overnight showers and embedded
thunderstorms will continue Saturday morning, gradually exiting
east through the late afternoon. Upper-level ridging centered over
the Desert Southwest will push into the area bringing more stable
air into the area. Given this, no severe threat is anticipated
with the lingering activity on Saturday. Rising heights will
promote drying and warming conditions for most locations across
the western and northern Sandhills in the wake of the exiting
activity. This will also lead to gradually clearing skies through
the afternoon into the evening as the activity exits off to our
east. High temperatures will remain below normal in the upper 70s
to low 80s with light northerly winds at 10 mph or less.
.LONG TERM...(Sunday through Friday)
Issued at 237 PM CDT Fri Jun 30 2023
A drier northwest flow aloft develops Sunday and continues into
Monday, while upper-level ridging across the Desert Southwest
continues to build into the region. High temperatures climb into the
upper 80s to low 90s on both days which is about 5 degrees above the
climatological normal for the beginning of July.
Active weather returns as abundant moisture advection from the Gulf
combines with multiple disturbances embedded within the flow aloft
and surface boundaries tracking across the area. This will result in
sufficient lifting and forcing for scattered shower and thunderstorm
chances across much of the area beginning late Monday night into the
latter end of the week. Confidence in the severe weather threat and
coverage remains low at this time given variability amongst
deterministic and ensemble solutions. Though the details remain
murky right now, the potential for another active and wet period
exists for the bulk of next week, including during the Fourth of
July holiday.
In addition to the increased potential for active weather, cooler
conditions are expected for Wednesday into Friday where high
temperatures in the 70s are forecast. In fact, both the NAEFS and
ENS ensemble guidance suggests that the mean temperature at H85 will
approach the 10th percentile of climatological percentile Wednesday
into Friday. Interestingly, for Thursday and Friday`s maximum
temperature, the EFI (Extreme Forecast Index) is suggesting
increased confidence of an anomalous event, such that the SoT (Shift
of Tails) is greater than zero.
These below normal temperatures and increased precipitation
chances are further highlighted by the CPC 6-10 Day Temperature
Outlook favoring below normal temperatures and the 6-10 Day
Precipitation Outlook favoring above normal precipitation. With
the potential for an active period ahead, make sure to keep up to
date with the latest forecasts as details get ironed out with
subsequent forecasts.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 635 PM CDT Fri Jun 30 2023
Scattered thunderstorms will persist across western and north
central Nebraska tonight and tomorrow morning, before ending
tomorrow afternoon. MVFR/locally IFR will be possible in any
thunderstorms. Additionally, low stratus development is expected
across portions of central and north central Nebraska into
tomorrow morning, with a period of MVFR possible. By early
afternoon, an improvement to VFR is anticipated area wide, and
this will persist into tomorrow evening.
Winds remain variable this evening before becoming northerly
tonight and tomorrow, at around 5 to 10kts. However, gusty
erratic winds can be expected in any thunderstorms.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...Brown
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
921 PM EDT Fri Jun 30 2023
.SYNOPSIS...
Southerly flow will transport heat and humidity into the area
over the next several days, leading to daily chances for showers
and thunderstorms. A cold front will move through the area on
Monday, before stalling to our south through the middle of next
week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
This evening features some theta-e advection from the southwest
beneath a ripple in northwest flow aloft. After earlier storms
fizzle in lower instability near the Chesapeake Bay, and outflow
boundary also moved to the southwest. Scattered to numerous
light showers and sprinkles have developed, with some deeper
convection in Augusta County. It does appear that the highest
chance of thunder for the rest of the evening will be near
Staunton-Charlottesville, southwest of the aforementioned
outflow and also southwest of extensive mid level cloudiness
(implying some stability farther NE). Recent CAMs indicate this
activity should wane near or after midnight.
For the second half of the night and toward dawn, the HRRR has
been insisting on scattered showers developing east of the Blue
Ridge and across the Baltimore/Washington area as the theta-e
ridge advances farther northeast. However, there`s less support
from other guidance. There`s also indication some remnant
upstream convection may approach the Alleghenies by dawn as
well.
Earlier storms and various wind shifts definitely disrupted the
remaining wildfire smoke/haze, although a smattering of
locations are still reporting haze, mainly from central Virginia
to southern Maryland. It`s unclear how this may evolve
overnight, but may remain in place if winds remain light.
Guidance also hints at patchy fog development west of I-95,
although this is a bit uncertain given abundant mid level
clouds. Overnight lows will be in the 60s for most, to around 70
in the urban areas and bayshore.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
The UL ridge will flatten heading into Saturday, resulting in
more zonal H5 flow. Guidance brings a convectively induced wave
near peak heating. However, some guidance brings in remnant
cloud debris from an upstream thunderstorm complex tomorrow
morning. This complicates the forecast and lowers uncertainty
wrt how much recovery there could be before the aforementioned
wave moves through. Overall chances for showers and
thunderstorms appear to be higher west of the Blue Ridge. The
environment looks seasonably moist with MLCAPE values near ~1500
J/kg and 20-25 kts of shear. Cannot rule out some strong to
severe storms. There is varying flow with height, so storms may
not initially move a lot resulting in a low end flood/flash
flood threat. Will also have to monitor upstream convective
activity for potential local impacts as some guidance has an MCS
in the Ohio Valley Saturday night or early Sunday morning. This
in turn complicates Sunday`s forecast.
Come Sunday, a potent trough will move through the Ohio Valley
with flow increasing ahead of this feature along with ample
moisture return. There is a notable overlap in CAPE and shear
Sunday, which could result in severe thunderstorms areawide.
Clear skies Sunday morning will result in a volatile
environment. Also possible convective debris Sunday morning
limits the convective potential locally.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Sunday night, all attention will turn to a very potent shortwave
trough over the Great Lakes. A strong MCS associated with this
system will make its way eastward across the Ohio Valley into Sunday
evening, before approaching the Allegheny Front Sunday night. The
biggest uncertainty lies with what it does after that. Decaying
MCS`s are one of the most difficult weather phenomena to predict,
and this is no exception. Guidance is still all over the place with
available instability east of the mountains overnight Sunday into
Monday. The most likely scenario is that the MCS decays as it
crosses the mountains, and areas see some residual showers and
clouds into Monday morning. However, should the higher end of
guidance hold true, we could see re-formation east of the Shenandoah
Valley somewhere. All in all, this is a very complex forecast, and
the Storm Prediction has our area highlighted with a Slight Risk as
a result, so it is something that is being closely monitored.
Beyond that, the primary upper trough should move through on Monday,
bringing another chance for afternoon showers and storms. The level
of severity is going to depend greatly on the events that occur
Sunday evening, and what amount of cloud debris is left over our
area. Best chance would be during the late afternoon/evening hours.
Into the middle of the week, we then move into a Bermuda High
pattern with a few weak disturbances passing through in WNW flow
aloft. This could spark off afternoon showers and storms, along with
terrain and marine driven diurnal circulations. As per the usual,
any of these could bring down some gusty winds briefly along with
heavy rainfall. We look to be setting into a summer-like pattern
finally, so look for this to continue.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
Earlier convection has cleared away from the metro terminals,
although showers and a few storms have been developing in the
central Shenandoah Valley. It appears the best chance for any
thunder through this evening will be near CHO, which is
southwest of an outflow boundary and has been less disturbed.
The HRRR model indicates some additional scattered showers may
develop across the metros late tonight, but confidence is too
low to include in the TAFs.
CHO is the only TAF site still reporting wildfire related haze.
It`s uncertain how this will evolve overnight, but it may
eventually transition to BR if no thunderstorms disrupt it.
The other concern later tonight will be low ceilings and/or fog.
There`s not a strong signal in guidance in what exactly will
unfold. Don`t think fog will be too widespread or dense given
abundant mid level cloud cover. Highest chance for IFR ceilings
will be at MRB, although this could expand further. Latest
guidance also generally kept the MVFR conditions west of I-95,
but this too will need to be monitored. Any deteriorated
conditions should dissipate quickly by mid morning Saturday.
The unsettled pattern continues Saturday afternoon through
Sunday night with multiple opportunities for
showers/thunderstorms. Saturday may be more diurnally driven
with convection potentially lasting into the overnight.
Uncertainty arises wrt any upstream MCS that may result in cloud
debris over the area and prevent convection from initiating in
the afternoon. Similar story on Sunday, though guidance
continues to bring a thunderstorm complex that will need to be
monitored closely toward the area Sunday night. Confidence
remains low wrt timing of this feature.
Scattered afternoon thunderstorms are forecast Monday, with lower
chances for Tuesday. Any storm either day will be capable of
producing brief periods of reduced CIGs/VSBY at any terminal. Gusty
winds are also possible with these storms. Outside of thunderstorm
activity, VFR conditions are expected to prevail.
&&
.MARINE...
S/SE winds haven`t been showing a particular increasing trend
after earlier storms, so am considering canceling the Small
Craft Advisory early. Winds will likely remain fairly steady
state overnight.
A similar setup for southerly channeling over the waters
appears possible Saturday afternoon/evening with SCA conditions
possible. However, confidence is low given a mostly marginal
performance Friday afternoon. Multiple rounds of additional
thunderstorms appear possible over the waters Saturday afternoon
through Sunday night.
Southerly winds Monday become southwest to west on Tuesday as a weak
cold front crosses the region early Tuesday. Winds are forecast to
remain below SCA criteria for most of the waters at the start of
next week. However, some southerly channeling is possible in the
southern bay waters, which could result in a short period of SCA
conditions Monday evening. Scattered thunderstorms are forecast
Monday afternoon/evening, with some storms likely able to produce
wined gusts at or above 34KT, in additional to lightning
strikes.
&&
.TIDES/COASTAL FLOODING...
Tidal anomalies will increase through the next day or two amidst
southerly flow. Sensitive location such as Annapolis, Baltimore,
DC Waterfront, and Straits Point are likely to reach Action
Stage during the early morning high tide cycle for the next few
days. Annapolis could reach minor flood stage with the tide
cycle early Sunday morning, and the other sensitive locations
could approach minor flood stage.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for
ANZ530>534-537>543.
&&
$$
SYNOPSIS...CPB
NEAR TERM...ADS
SHORT TERM...CPB
LONG TERM...CJL
AVIATION...ADS/CJL/CPB
MARINE...ADS/CJL/CPB
TIDES/COASTAL FLOODING...CPB
Area Forecast Discussion
National Weather Service New York NY
1030 PM EDT Fri Jun 30 2023
.SYNOPSIS...
High pressure weakens and will become based in the Western
Atlantic tonight into Saturday. A warm front approaches
Saturday night. A warm front moves through Sunday into Sunday
night. A cold front approaches Monday and likely pushes through
into Tuesday. Weak high pressure should assume control Wednesday
and Thursday. A cold front may approach towards the end of the
week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
For this update the only slight adjustment was to prolong haze
in weather grids for a bit longer in the night.
With a weak pressure gradient and diurnal cooling, winds will
decrease and will remain light. These winds will be southerly
and will allow for a relatively warmer night on average compared
to the previous night. No rain is expected.
A little more cooling across interior and eastern locations
with more maritime influence will allow for any fog to develop
in these locations first with more development elsewhere closer
to daybreak Saturday. Kept fog forecast coverage at patchy and
mainly east with model uncertainty in surface visibilities.
Concerning the residual smoke and haze, according to the HRRR,
the concentration lowers along the southern and coastal portions
of the region where winds will be relatively higher. However,
the residual smoke and haze is forecast to linger across
interior areas north and west of NYC this evening getting
gradually less later at night. In essence, less smoke and haze
overall is forecast later in the overnight.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
For Saturday, there is more SE flow and this will increase
across the coastal sections of the forecast region with high
pressure centered well out into the Atlantic. This will make
for an increase in spatial temperature gradient with warmer
temperatures across western sections of the forecast region and
cooler temperatures across the coastal sections. The range of
max temperatures will be upper 70s to mid 80s with some
localized spots in the upper 80s in NE NJ. Mainly sunny sky
conditions to start the day with any residual fog burning off in
the morning. Clouds increase in the afternoon.
For Saturday night, the continued onshore southeast flow will
result in an increase in humidity as well as relatively warmer
temperatures with abundant cloud coverage. A warm front
approaches late and could allow for some rain shower development
across far western sections overnight. Otherwise, expecting
more patchy fog which could be more expansive along the coast.
Due to model uncertainty, left as patchy fog coverage. Lows are
forecast to range from the mid 60s to near 70 across the area.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Sunday at this time looks to be the first day the area gets into the
warm sector. With the moisture content in the column increasing
during the day, look for scattered to isolated shower and t-storm
activity. Any potential hazardous weather on Sunday would likely be
localized heavy rain in association with any thunderstorms that can
form on weaker boundaries, perhaps sea breeze boundaries. The latest
guidance is indicating an overall lack of instability to start on
Sunday, with perhaps instability increasing, at least elevated
instability later Sun and Sun night. WPC has a marginal risk of
severe weather for Sunday and Sunday night; mainly for the southern
half of the area. The mid and upper levels may not be primed with a
lack of cyclonic curvature / vorticity in the mid and upper levels
during the day Sunday.
By Monday the thunderstorm / severe weather potential looks more
favorable at this point in terms of the synoptic set up. The area
will be deeply embedded in the warm sector. Dew points look to be
likely in the lower 70s across a good portion of the region with a
pre-frontal trough getting into the area. The mid levels will have
more cyclonic curvature with medium range guidance suggestive of
shortwave energy pivoting into the region. BUFKIT soundings from the
GFS indicate the potential for multiple hazards in relation to t-
storm activity. PWATs look to be off the charts from a climo
perspective, at or just above 2 inches. There also appears to be
adequate shear for storm organization. What is not predictable this
far out is if any mitigating factor such as morning cloud cover
which would limit more widespread severe t-storm potential. In any
event, Monday looks to be a day to keep an eye on.
By Tuesday the 4th, look for the southern portion of the mid /
upper level trough axis to push through at some point during the
morning or perhaps as late as the early afternoon. If the
system moves slower any shower and t-storm activity from Mon
evening could linger into early Tue morning. In the lower levels
it seems likely somewhat drier air begins to filter in with a
cold frontal passage. It would seem with a trough aloft that
there would at least be a chance of some scattered afternoon
convection on Tue, especially further north and east across the
area.
Mid levels heights should recover enough to promote a cap on any
convection getting into the mid week beginning on Wed, and likely
lasting through the first half of Fri. Kept PoPs minimal for the Wed
through early Fri time frame, then start to increase PoPs from west
to east on Fri as the next frontal system arrives based on global
model consensus.
With respect to temperatures, look for minimum temperatures to
average a bit above normal through the period due to mainly higher
overall humidity. Daytime maxes should average below normal on
Sunday due to cloud cover, and then approach more normal levels on
Monday with some afternoon breaks of sun. For the remainder of the
next week look for daytime maxes to average a few degrees above
normal, especially across urban areas and across the interior.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Weakening high pressure just offshore will continue to move
slowly east.
Most sites except KSWF are now VFR as of 02Z, but with
haze/smoke aloft. Light onshore flow should lead to development
of fog and low stratus overnight at KGON, and may bring brief
MVFR cond to KISP toward daybreak.
Latest HRRR smoke forecasts for daytime Sat appear more
optimistic, and vsby could remain VFR at most sites or drift
in/out of MVFR mainly during the afternoon.
Light SE-S flow will increase again to at least 5-10 kt, and to
around/just over 10 kt at KJFK/KLGA during the afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
AMD possible to address flight cat changes due to haze/smoke.
OUTLOOK FOR 00Z SUNDAY THROUGH TUESDAY...
Saturday night and Sunday: Showers possible and chance of
tstms. Brief MVFR likely, IFR possible.
Monday and Tuesday: Chance of afternoon/evening showers/tstms,
otherwise VFR.
Wednesday: Mainly VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
With a weak pressure gradient in place across the forecast
waters through Saturday night, conditions are expected to remain
below small craft advisory thresholds.
Sub small craft conditions take place on Sunday with ocean seas
around 4 ft and gusts up to 20 kt. Marginal small craft conditions
are expected out on the ocean Monday afternoon and evening just
ahead of a cold front on a S to SSW flow with 4 to 5 ft seas. On
Tuesday 4 ft seas are expected before seas decrease to around 3 ft
into Wednesday with the winds mainly out of the SW to S.
There will be a chance of thunderstorms Sunday, Monday, and Tuesday,
with the best chance at more widespread thunderstorm activity on
Monday. On these days there could be locally hazardous conditions in
relation to thunderstorms.
&&
.HYDROLOGY...
No hydrologic issues expected through Saturday night with no
widespread heavy rainfall expected.
There will be a localized threat for flooding in association with
any stronger t-storms producing heavy rain on Sunday. Currently WPC
has a marginal risk of excessive rainfall on Sunday. On Monday there
remains a risk of localized flooding with any stronger t-storms.
There will be no hydrologic impacts for the remainder of the week,
Tuesday through Friday.
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip currents is expected Saturday into Sunday
morning. A high risk of rip current development can be expected
towards Sunday afternoon and evening for the NYC, Nassau, and SW
Suffolk beaches, with a moderate risk being maintained for the E
Suffolk beaches.
With astronomical tides increasing this weekend with the approach of
a full moon on Monday, minor coastal flooding looks possible to
likely with the evening high tide cycles for Sunday and Monday.
Areas most likely to be affected are the south shore bays of Nassau,
Queens and Brooklyn, Staten Island, and Southern Fairfield /
Westchester Counties.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT this evening for CTZ005>012.
Air Quality Alert from 11 AM to 11 PM EDT Saturday for
CTZ005>012.
NY...Air Quality Alert until midnight EDT Saturday night for
NYZ067>075-078>081-176>179.
NJ...Air Quality Alert until midnight EDT tonight for NJZ002-004-
006-103>108.
MARINE...None.
&&
$$
SYNOPSIS...JE/JM
NEAR TERM...JE/JM
SHORT TERM...JM
LONG TERM...JE
AVIATION...BG
MARINE...JE/JM
HYDROLOGY...JE/JM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
National Weather Service Charleston WV
946 PM EDT Fri Jun 30 2023
.SYNOPSIS...
Hot and humid weather builds into the weekend, along with
shower and thunderstorm chances. More typical summertime
pattern returns for the new work week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 930 PM Friday...
Made minor updates to overnight temperatures, cloud cover, and
PoPs based off the latest trends. A generally quiet night ahead,
with some isolated showers/storms possible later tonight across
the Mid-Ohio Valley region. Additionally, some valley fog will
develop as the night progresses, primarily across the deeper
valleys of VA/WV. The rest of the forecast remains on track.
As of 200 PM Friday...
Upper level ridge has shifted slightly east, allowing for H500
shortwaves to dig into our area under northwest flow aloft. Some of
the Hi-res CAMs models bring a shortwave into our area by 08Z
tonight. Better model consensus exist Saturday afternoon (18Z)
bringing another but stronger shortwave by 18Z Saturday. This poses
a threat for a convective complex to feed from diurnal heating and
enough moisture to produce stronger convection with the afternoon
feature, with the potential for some storms to become strong to
severe. Yet, another shortwave is suggested by hi-res models
arriving to southeast OH late Saturday night. SPC continues
highlighting the entire area under a slight risk for severe
thunderstorms for Saturday.
Muggy conditions are likely tonight with dewpoints in the lower
70s. Tonight`s temperatures will range from the upper 60s
lowlands, into the upper 50s highest elevations. On Saturday,
temperatures will depend on cloud cover and whether cooling
showers materialize. Saturday`s highs will reach the lower 90s
across the lowlands, ranging into the mid 70s highest
elevations of our northeast mountains.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 122 PM Friday...
Key Points:
* System moves in from the west and brings some strong to
severe storms late afternoon and evening on Sunday.
* Main threats: Gusty winds, hail, heavy rain, and low chance
for an isolated tornado.
* Very warm to even hot temperatures with humid conditions.
Confidence is starting to increase in the likelihood of severe
weather Sunday. A 500MB low pressure system moves down from the
Great Plains and over IL/IN, breaking a subtle ridge of high
pressure over our region. By the evening hours, a shortwave
will move across Ohio and approach the western periphery of the
CWA.
The NAM and RAP project CAPE values between 2,000-4,000 J/Kg,
sfc-500MB bulk shear values around 50 kts, high dew points, and
lift from the cold front. All of these being indicators for
severe weather. The issue will be that the vort max is projected
to be over IN/MI/OH during the afternoon, when our parameters
will be most prime. That said, by the time it arrives around
6-7PM Sunday the instability may not be as strong(1,000-3,000
J/Kg), as if it were to arrive earlier in the day.However, the
strength of this system will likely make up for any
shortcomings in the conditionally unstable environment.
The main threats with this system will be damaging winds, hail, and
heavy rain. With a fairly adequate wind profile, an isolated
tornado cannot be ruled out for SE Ohio, NW West Virginia,
southern coalfields, and the Tri-State Area. Embedded rotation
or an isolated tornado in these areas is low chance, but not
out of the question.
Temperatures will be in the upper 80s and lower 90s all across the
lowlands; with the mountains in the 70s, 80s, and even around 90 in
the southern mountains. It will feel oppressive with dew points
in the 70s and upper 60s.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 145 PM Friday...
Key Points:
* Cold front moves through the area Monday.
* Chances for afternoon showers and thunderstorms every afternoon.
* Cooler and drier on Monday, heat builds back in Tuesday
and stays through the week.
The rowdy cold front that spawns storms on Sunday moves through
the area Monday, bringing a brief reprieve from the heat (lower
80s-lowlands, 60s & 70s-mountains). Dew points will lower
slightly due to dry air. Very warm and hot weather by Tuesday
and continuing through the week with spots in the lowlands
reaching the upper 80s, flirting with 90 each afternoon. Chances
for showers and thunderstorms each afternoon too with a
typical, summertime pattern in place.
May see the Canadian wildfire haze return for the beginning of
next week due to post-frontal NW`rly flow. Uncertain how long
that will stick around as high pressure builds in and a warm
front approaches from the south, subsequently shifting the
winds.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
As of 810 PM Friday...
Mainly dry conditions persist tonight, with some isolated
showers/storms possible late across the Mid-Ohio Valley. Valley
fog is progged to develop overnight, particularly across the
deeper valleys of VA/WV, where some IFR/LIFR restrictions are
possible. Any fog that does develop will lift/dissipate by ~
12-13Z. Isolated/scattered showers and thunderstorms will be
possible on Saturday, particularly in the afternoon/evening
hours. Given such, did insert VCTS into the TAFs beginning mid
afternoon. Brief IFR/MVFR VSBY restrictions will be possible
within heavier showers or any thunderstorms, along with gusty
winds. Otherwise, VFR is progged during the day on Saturday.
Calm or light (southerly) surface flow is progged for tonight,
with light southwest flow on Saturday.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Fog timing and coverage tonight may vary
from the forecast. Timing and coverage of expected convection on
Saturday may also vary from the forecast.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 07/01/23
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H L L L L L
HTS CONSISTENCY H H H H H H H H H H H L
BKW CONSISTENCY H H H H H H H H M M M M
EKN CONSISTENCY H H H H H H H L M M M L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H M L M M M M
AFTER 00Z SUNDAY...
IFR conditions are possible in showers and thunderstorms through
Monday morning.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...ARJ/GW/LTC/TW
NEAR TERM...ARJ/GW/TW
SHORT TERM...LTC
LONG TERM...LTC
AVIATION...GW
Area Forecast Discussion...UPDATED
National Weather Service Springfield MO
655 PM CDT Fri Jun 30 2023
Key Messages:
1. Dangerous heat this afternoon with temperatures near 100
degrees. Heat Advisory in effect.
2. Scattered thunderstorms and slightly cooler temperatures this
weekend. Marginal to Slight Risk for severe storms Saturday
afternoon and Saturday night for most areas with an Enhanced
severe risk for the far eastern Ozarks.
3. Scattered showers and storms for Monday and Independence Day.
No all day washouts.
.SHORT TERM...(This evening through Saturday)
Issued at 225 PM CDT Fri Jun 30 2023
Synoptic Scale Pattern and Current Conditions: Upper level high
pressure remains established from the Mid-Mississippi Valley into
the western Gulf of Mexico. The center of the 500 mb high is
analyzed along the I-20 corridor across Louisiana and Mississippi.
Meanwhile, an upper level short wave trough is progressing east
across the northern and central High Plains. Weak surface low
pressure is analyzed ahead of that trough across central Kansas. A
stationary surface frontal boundary extends in an almost west to
east fashion on either side of the low from southeastern Colorado
into northern Missouri.
South of that front, hot and humid conditions persist this afternoon
across the Missouri Ozarks and southeast Kansas. The 12Z KSGF
sounding measured an 850 mb temperature around 26C which is near
climatological maximums for late June. These warm 850 mb
temperatures and overall subsidence beneath the upper level ridge
have once again supported afternoon temperatures in the upper 90s
to around 104 degrees.
Heat indices this afternoon are again running between 100 and 108
degrees given surface dew points in the upper 60s to lower 70s.
The ongoing Heat Advisory has this well covered through 7 PM this
evening.
Visible satellite imagery depicts a few pockets of cumulus
clouds. Little vertical growth has been noted due to subsidence
beneath the upper level ridge. The closest radar returns are up
across southern Iowa.
Thunderstorm Potential this Evening and Tonight: There will be a few
potential areas to key in on for scattered thunderstorm potential.
The area of highest confidence will be that frontal boundary as it
sags south and southwest across northern Missouri.
Convective initiation initially appears probable across eastern
Missouri and western Illinois as the cap breaks late this afternoon
and early this evening. Another area of scattered convection is then
probable along the I-70 corridor from northern Kansas through the KC
metro as upper level height falls begin to overspread that region
ahead of that short wave trough.
Coverage in storms should then increase across northern Missouri
from late this evening into the overnight period as a low-level jet
noses into the I-70 corridor and induces isentropic upglide. There
is some potential for these storms to glance our central Missouri
counties, however wind fields will tend to keep these storms north
of the area. Any storms that can manage to clip our counties will
have a marginal risk for being severe, with outflow winds up to 60
mph being the primary potential severe weather hazard.
A low confidence scenario we will also be monitoring tonight will
be the potential for isolated elevated convection to develop and
shift northeast across southern and then central Missouri. The
last several runs of the RAP indicate little or no capping for
parcels lifted in the 875-725 mb layer. If localized areas of
isentropic ascent are able to develop along the eastern flank of
that developing low-level jet, this may be just enough for an
isolated storm or two. Right now, we are only putting the
probability for this scenario occurring at 10-15%.
Slightly Cooler Saturday with Thunderstorm Potential: The
aforementioned short wave trough will continue to move east into the
northern and central Plains. In response, that cold front will
slowly drift southeast across southeast Kansas and into west-central
Missouri by 00Z Sunday. This front will then move southeast across
the area Saturday night and will clear south-central Missouri by 12Z
Sunday.
While CAMs vary considerably regarding the placement and
coverage of convection, we are confident that we will see scattered
thunderstorms on Saturday and Saturday night. There appear to be two
scenarios that will come into play for thunderstorm potential from
Saturday into Saturday night.
Scenario One: A leading short wave trough ahead of the main upper
level trough may be enough to remove the cap and produce scattered
thunderstorms, especially along and east of the Highway 65 corridor
Saturday afternoon. This activity may grow upscale into a
mesoscale convective system (MCS) as it pushes into eastern
Missouri.
Scenario Two: Convergence along the southeastward moving surface
cold front may produce scattered thunderstorms from late Saturday
afternoon into Saturday night.
PoPs for these two scenarios remain relatively unchanged and in
the 40-70% range. Not all areas will get rainfall. However, the
12 HREF localized probability-matched mean QPF product does
indicate that localized areas may receive 2-3" of rainfall.
We will also be monitoring the potential for severe storms from
Saturday afternoon into Saturday evening. It is possible that
scattered morning convection may tend to limit instability across
portions of the Missouri Ozarks as cloud cover lingers into the
afternoon. However, the last few runs of the SREF indicate 50-70%
probabilities for MLCAPEs exceeding 2000 J/kg across much of
central and southern Missouri. Meanwhile, short term models have
been consistent in advertising 0-6 km bulk shear magnitudes in the
25-40 knot range, with the highest values across the eastern
Ozarks.
This CAPE/shear combo will be supportive of severe thunderstorm
potential, especially across the eastern Ozarks where deep layer
shear will be strongest. The main potential hazard will be
damaging winds to 70 mph, especially across the eastern Ozarks if
cold pools congeal and storms grow upscale into a linear MCS.
Otherwise, hail to the size of ping pong balls will be possible
across the eastern Ozarks with any storms that can obtain
supercell characteristics before growing upscale. Max hail sizes
across the remainder of the Missouri Ozarks would be half dollars
with max thunderstorm wind gust potential at 60 mph.
High temperatures for Saturday are a tough call given the
expectations for scattered convection and associated cloud cover.
Areas of the eastern Ozarks will still likely warm into the lower or
even middle 90s before storms increase in coverage in the afternoon.
We will have to watch afternoon heat indices across the eastern
Ozarks as they may again push 100 degrees as surface dew points
remain in the upper 60s to lower 70s. We considered adding another
day to the Heat Advisory for the eastern Ozarks, but confidence in
reaching criteria is only low to moderate given the expected
afternoon storms. If confidence further increases in 100+ heat
indices, a shorter-fused advisory will be in play.
Meanwhile, areas along and west of the Highway 65 corridor should
see slightly cooler highs with more in the way of cloud cover and
850 mb temperatures decreasing by 2-3 degrees Celsius. It should be
noted that there is some decent spread in the NBM statistical data.
A middle of the road scenario puts highs in the upper 80s and lower
90s. Less cloud cover would result in highs pushing the middle 90s
while more cloud cover and convection would keep highs in the middle
80s.
Sunday: The main upper level trough axis will pass through the
region. Scattered showers and thunderstorms will again be possible
(NBM 30-50% chance) mainly east of Highway 65. Instability looks too
limited at this point for any severe storm potential.
Temperatures will remain slightly above normal for this time of
year with highs in the upper 80s to lower 90s. Dew points for
Sunday will drop back into the middle to upper 60s which will at
least make conditions a bit more comfortable.
.LONG TERM...(Saturday Night through Friday)
Issued at 225 PM CDT Fri Jun 30 2023
Monday through Wednesday: Ensemble systems indicate that the upper
level ridge will become more established over the southwestern U.S.
with height rises across the Missouri Ozarks. This will result in
warming temperatures with highs returning to the lower to perhaps
middle 90s.
The potential does exist for isolated to scattered thunderstorm
activity on Monday and for the Fourth of July as a weak upper level
disturbance traverses the area on the northern periphery of that
ridge. Thus, those with outdoor plans should keep up for the
forecast as we refine PoPs and timing.
Pattern Change Late Next Week: WPC cluster scenarios reveal a
flattening of that ridge with rather high amplitude upper level
energy traversing east through the southern Canadian provinces and
northern tier of the CONUS. This should support a decent cold front
driving south through the area sometime Wednesday night or Thursday.
This will bring us a good shot at much needed rainfall with a
significant cooldown then ensuing to end the week.
Second Week in July: The Climate Prediction Center (CPC) has
highlighted the entire area with 50-60% chances for above normal
precipitation for the July 7-13 time period. Chances for near normal
precipitation are at 33% with below normal chances in the 10-15%
range. These above average precipitation probabilities are supported
well by the GEFS and CMC ensembles. The ECMWF ensemble is more
neutral when it comes to potential for above or below normal
precipitation.
The CPC has highlighted the area with a slight signal for below
normal temperatures. This weak signal is reflected in the different
ensemble systems with the GEFS pretty bullish on below normal
temperatures with the ECMWF and CMC ensembles neutral.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 644 PM CDT Fri Jun 30 2023
VFR is forecast to persist through the night with partly cloudy
skies and light southwesterly winds. As for Saturday, scattered showers
and thunderstorms have a chance (30%) to start after sunrise for
JLN and slowly push east throughout the day. Added PROB30 groups
in for SGF and BBG around noon. Southwesterly winds will be gusty
around 25 knots through the afternoon. Large hail and damaging
winds are the primary hazards with these storms tomorrow.
&&
.CLIMATE...
Issued at 232 AM CDT Mon Jun 26 2023
Record highs for Friday:
Springfield 99 in 2012
Joplin 100 in 2011
West Plains 101 in 2012
Vichy 102 in 2012
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory until 7 PM CDT this evening for MOZ055>058-066>071-
077>083-088>098-101>106.
KS...Heat Advisory until 7 PM CDT this evening for KSZ073-097-101.
&&
$$
SHORT TERM...Schaumann
LONG TERM...Schaumann
AVIATION...Soria
CLIMATE...Lindenberg