Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/22/22
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
630 PM CDT Thu Jul 21 2022
.UPDATE...
Issued at 616 PM CDT Thu Jul 21 2022
Updated aviation discussion below. Pops and sky cover have been
increased across the northeastern CWA. Two large storms across
south central ND should continue moving southeast over the next
few hours, potentially impacting the northeast CWA. Still a good
amount of CIN in this CWA so the storm should diminish some along
their southeast track.
&&
.SHORT TERM...(This Evening through Friday Night)
Issued at 250 PM CDT Thu Jul 21 2022
Shortwave activity continues to move through the upper level west to
northwest flow. There has been a line of showers moving southeast
through North Dakota this afternoon that follows that shortwave
trajectory into northeast SD. Some models have some
intensification/amplification of the shortwaves across far northeast
SD and west central MN this evening. Similar to last night, shear
remains high, but CAPE, on the RAP and HREF, at least, is
marginal...around 1000 J/kg or less.
SPC has a marginal risk this evening for areas south of Pierre.
While there is a weak low that is expected to move east across far
southern SD this evening, most models show the best forcing
remaining south of this forecast area. That said, there will be a
weak 25 kt llj that develops ahead of the low after 3z, so can`t
completely rule out some thunderstorm development with the jet.
Above normal highs are forecast again on Friday as heights rise
slightly with a minor amplification/shift of the upper ridge. A low
pressure system will move off the Rockies and into SD Friday night.
This system may set off some scattered showers and thunderstorms,
especially across the north and east.
.LONG TERM...(Saturday through Thursday)
Issued at 250 PM CDT Thu Jul 21 2022
The long term forecast features lower, near normal temperatures and
periodic precipitation chances, as the upper-level flow pattern
shifts into predominantly northwest flow. Beginning at 12z Saturday,
a ~1004mb sfc and NE/SW-oriented cold front will be positioned
across the middle of South Dakota. Aloft, a potent shortwave trough
will be digging east-southeast through the region. Models have
slowed this system down a bit, which will allow for warmer daytime
high temperatures Saturday, especially across south central and
northeastern SD and west central MN. Still, the anomalously hot air
aloft peaks Saturday morning, with 10 to 15C 700mb temps at 12z (per
NAEFS and ECMWF ensemble means), and then quickly cool post-frontal
through the afternoon and evening. Good forcing and support aloft
will lead to showers and thunderstorms across the eastern CWA
Saturday morning (30-60% chance), and activity may linger into the
early afternoon ~along and east of the Prairie Coteau as well.
Models range quite a bit on how much instability will be present
Saturday morning along/ahead of the front, with MUCAPE values
generally between 1000-2000 J/kg due to potentially steep mid-level
lapse rates and dewpoints in the mid 60s. This, coupled with strong
deep-layer shear near/behind the front, will provide a window of
opportunity for storms to organize and approach or exceed severe
limits.
Post-frontal, northerly winds will become breezy with gusts around
30 mph, or stronger across central SD Saturday AM and afternoon.
While mostly dry Sunday under high pressure (a weak disturbance may
bring showers/storms across south central SD Sunday night), another
notable shortwave and associated sfc low and cold front will track
through the region from northwest to southeast on Tuesday. Shear and
instability may be sufficient for the potential for strong storms
with this system as well, though confidence is low at this time.
This system will bring a reinforcing shot of cooler air too. The WPC
Cluster Page shows all available ensemble members in good agreement
about the overall northwest flow pattern across the Northern Plains
continuing through the rest of the week, though the ECMWF tries to
build in a higher-amplitude upper-ridge across the western US than
the GEFS. This suggests that a return to above normal temperatures
is on the table during this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 616 PM CDT Thu Jul 21 2022
Terminals KABR,KATY,KPIR,KMBG
Prevailing VFR conditions can be expected through the valid TAF
period. Thunderstorms over south-central ND should continue moving
southeast over the next few hours, potentially impacting the
terminals of KABR and KATY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...SD
SHORT TERM...Wise
LONG TERM...Lueck
AVIATION...SD
Area Forecast Discussion
National Weather Service Columbia SC
848 PM EDT Thu Jul 21 2022
.SYNOPSIS...
Scattered storms are again expected on Friday afternoon and
evening, with some strong storms possible. By the weekend and
into the middle of next week, a typical summer pattern with
seasonable temperatures and mainly diurnal showers and
thunderstorms are expected each afternoon and evening.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Isolated showers and storms in the southern half of the forecast
area early this evening will continue to weaken into tonight. Water
vapor imagery indicates some drier air aloft pushing into the
forecast area. General upper troughing remains over the area and
while recent CAMs runs indicate most of the area will remain dry
overnight, around daybreak some showers will be possible along a
surface trough in the southeastern portion of the forecast area.
Temperatures remain in the low to mid 70s overnight.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Fairly normal summertime pattern expected to continue across
Midlands of South Carolina and CSRA of eastern Georgia. Weak
troughing will still be in place across the region on Friday, while
height rises towards Saturday will help to weaken the
persistent troughing that has been in place for a few days. At
the surface, a weak front/boundary will still be in place
stretching from eastern NC through northern SC and into Georgia.
Along and south of this will be plentiful moisture, with PWs
around 2" or greater in the central and southern portions of
the area on Friday afternoon. With good heating and surface
dewpoints, this should yield good instability values, with the
general consensus of 1000-2000 j/kg of CAPE forecast to develop
by Friday afternoon. It looks like a weak 700 hPa shortwave is
forecast to pass along and north of the surface front, which
should help to spark at least scattered showers and
thunderstorms during the afternoon and evening hours. Some
isolated strong storms are possible, but not expecting
widespread strong to severe storms at this time. Additionally,
we have seen convection across the region the past two mornings,
and I can`t rule that out again given the pattern persistence.
Latest HREF does hold on to convection across the region
tomorrow morning ahead of the weak surface boundary, so added
low-chance PoPs to the grids to account for that. Highs Friday
will likely be in the upper 80s across the region, but may get
into the 90s if we clear clouds out quickly enough. Rinse and
repeat on Saturday, as the boundary only slowly moves out of the
region. This should yield another chance at showers and storms,
with a few being strong. I think overall chances will be a bit
lower on Saturday, with the best chances across the south where
the boundary may end up. Highs will again be in the low 90s,
with lows in the low 70s both nights.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Seasonal is the word for the long term period, as typical summer
weather is expected through next week. Ridging will increasingly
build across the region, but underneath that will be a weak inverted
trough at 500 hPa and 700 hPa on Sunday afternoon and Monday. PWs
will be near normal for this time of year, but less than they have
been. Guidance shows values around 1.5"-1.8", which should be
enough to yield some showers and isolated storms on
Sunday/Monday, but overall coverage looks a bit limited. This
actually begins a period of normal to slightly below normal PWs
in the models through the end of the period. Even still,
ensembles and operational models are in good agreement on the
further development of mid-level ridging (500 hPa heights rising
to ~594 dm by middle of next week) and a bermuda high to our
east. This will lead to seasonal chances of isolated to
scattered showers and storms each afternoon, with highs in the
low- mid 90s, and overnight lows in the 70s.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Little convection this evening across the area outside of a
couple of showers approaching DNL/AGS. Expectation is that these
showers will dissipate before reaching the terminals, although
will amend as needed. Otherwise, generally expecting VFR
conditions into the overnight hours with scattered mid and high
level clouds with diminishing wind below 5 knots overnight.
HRRR is again hinting at possible stratus development during the
predawn hours through midday arriving from the southwest with
some support from the MET guidance while other sources keep VFR
conditions. Decided to include a tempo for MVFR cigs after
10z-11z and include prevailing MVFR cigs after 15z with abundant
low level moisture in place. Winds will pick up from the
southwest around 5 to 8 knots. Scattered convection expected
again but confidence not high enough to include mention of
storms in the forecast at this time.
EXTENDED AVIATION OUTLOOK...Some possibility of patchy late
night/early morning fog/stratus late Friday night/early Saturday
morning. Less diurnal thunderstorm coverage expected Sat/Sun.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Cleveland OH
1024 PM EDT Thu Jul 21 2022
.SYNOPSIS...
A weakening cold front will move across the area from west to
east late tonight and Friday morning. After brief high pressure
Friday afternoon through early Saturday, a warm front lifts
across the area on Saturday. A cold front sinks out of the Great
Lakes and moves across the local area Sunday night or Monday,
before stalling across the Ohio Valley early next week.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
10:00 PM Update...
Raised PoPs to likely in NW Ohio and also moved up the onset of
showers and thunderstorms due to the small MCS moving ESE across
southern lower Michigan. This feature has produced some damaging
winds and localized hail in SW Michigan and is being driven by a
mid-level vort max and 30-35 knot low-level jet. Downstream
instability is waning in northern Ohio with MUCAPE now falling
into the 500-1000 J/Kg range per latest RAP analysis, so expect
a weakening trend as this complex enters NW Ohio. But with its
forward speed and radar/satellite presence, feel confident that
most of NW Ohio will see rain and thunder after 03Z. Gusty winds
and heavy downpours will accompany the strongest cores. For the
rest of the night, adjusted the PoP forecast to bring showers
across the rest of northern Ohio and NW PA about an hour or two
faster than the previous forecast, but amounts and coverage will
be less compared to NW Ohio.
6:30 PM Update...
The forecast remains on track through tonight with no changes
made. The weak surface trough has exited SE across PA taking the
isolated showers with it. This will leave mostly sunny skies and
very warm, although slightly less humid, conditions for the rest
of the evening as drier air and some subsidence advect in. The
next feature to watch is a weak mid-level shortwave and
associated vort max currently crossing Lake Michigan. An 80+
knot upper jet and MUCAPE of 1000-2000 J/Kg are generating a
few thunderstorms beneath this feature, so scattered
showers/storms should cross northern Ohio tonight as the
shortwave continues to progress rapidly through the WNW flow
aloft. Current mesoanalysis indicates MUCAPE of 1000 J/Kg across
northern Ohio, and this is expected to decrease after sunset,
but lift from the entrance region of the aforementioned jet and
vort max should still support a few showers and rumbles of
thunder. CAMs differ on coverage, but timing consensus moves the
majority of this activity through NW and north central Ohio in
the 06-09Z timeframe and NE Ohio and NW PA in the 08-12Z
timeframe, so kept PoPs as is. It`s possible that an isolated
shower could reach NW Ohio as early as 02Z, but most of the
activity will be in the aforementioned windows.
Original Discussion...
A warm, tranquil and somewhat breezy late afternoon and early
evening. Enough low-level moisture present near and east of the
I-71 corridor for a decent cumulus field this afternoon, and
it`s possible there`s a brief sprinkle somewhere from Trumbull
to Stark Counties points southeast before 6 PM, but didn`t put
in mentionable POPs. Dew points gradually falling through the
60s today with temperatures ranging from the mid 80s to near 90
at the moment.
A low amplitude shortwave will zip out of the upper Midwest and
through the southern Great Lakes tonight into early Friday. It`s
a small, quick-moving system in an otherwise ridgy/dry regime,
and generally moves through our area at the diurnal minimum.
However, it brings with it a brief shot of large scale ascent
beneath the right-entrance quadrant of a small upper-level jet
streak, with low-mid level warm/moist advection, a well-defined
low-mid level trough axis, and 1000-1500 J/KG of elevated CAPE
moving west-east across our area overnight tonight into early
Friday. With decent agreement among today`s guidance that
isolated to scattered showers/thunder will quickly move across
the area with this shortwave late tonight into early Friday,
generally raised POPs a bit across the board and hit everyone
with 20-50% chances briefly, with chances ramping up into
Northwest OH nearing midnight and then exiting our area early
Friday. Highest POPs over Lake Erie, northeast OH and into PA,
gradually dropping off to the south/southwest. Not expecting any
severe or flooding threat late tonight or early Friday, but
don`t be surprised if there are some stray rumbles of thunder
that wake some people up early in the morning. Lows tonight
range from the mid 60s to around 70, warmest in northwest OH and
in the urban centers.
Lingered some low POPs from into early Friday from northwest PA
into east-central Ohio until the trailing surface trough clears,
but am expecting dry conditions on Friday after this exits by
around midday. If surface convergence lingers longer that may
be enough to keep a stray shower or rumble around with some
surface-based instability developing with daytime heating, but
it would be quite isolated and am not confident so continued
with a dry forecast after we clear everything out in the
morning. Another warm one for Friday, ranging from the mid 80s
in PA to the mid-upper 80s for most of northern Ohio, but into
the lower 90s for Toledo.
Largely quiet for Friday night with high pressure in control and
a dry/stable environment, but can`t rule out the remnants ridge
riding convection over the Upper Midwest bringing shower chances
to northwest Ohio towards dawn Saturday.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Generally a quiet start to the short term period on Saturday, though
the weather will become more active by Sunday.
Lingering showers and/or isolated thunder chances may be possible
associated with a decaying MCS Saturday morning and early afternoon,
though not anticipating anything too significant. Behind this
activity, warm air advection will really begin to increase across
the region, with substantial capping in place to prevent any
additional showers and/or thunderstorms. Above average temperatures
in the upper 80s to lower 90s are expected with muggy conditions.
On Sunday, an upper trough axis will move east across the Great
Lakes, extending a cold front south across the Lower Great Lakes.
Latest model guidance is suggesting modest, westerly mid-level flow
of around 35 to 40 knots by Sunday afternoon and evening just ahead
of the front, resulting in the potential for scattered to perhaps
widespread showers and thunderstorms. The severe threat, especially
for damaging winds, has increased slightly with this update, given
model increases in shear and CAPE, but will be dependent on how
unstable the area is able to get, given anticipated cloud cover.
Nonetheless, the heavy rain threat remains apparent across the
region Sunday evening and overnight, given an anomalously-moist
airmass, characterized by PWATs around 2.0 inches, and projected
west to southwest storm motions nearly paralleling the front
axis.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
Latest guidance is suggesting that the aforementioned cold front on
Sunday evening and overnight will stall just south of the US-30
corridor by Monday and thus we could see additional shower and/or
thunderstorm develop along or south of the US-30 corridor in the
afternoon and evening hours. On Tuesday, the front will sag slightly
further towards the south as weak high pressure builds south across
the Great Lakes. Initial thinking is that much of the area will
remain fairly dry, though can`t rule out a stray shower and/or
thunderstorm in the afternoon and evening. Temperatures will
generally be near average in the low to mid 80s on both Monday and
Tuesday.
By Wednesday into Thursday, the stalled front will begin to lift
back north as a warm front, ahead of the next upper trough sweeping
east across the Great Lakes region. Average to above average
temperatures in the low to mid 80s are expected in addition to a
muggy air mass. Still some timing differences on the upper trough
and associated cold front, though could see shower and thunderstorm
development on both the afternoon and evening hours of Wednesday and
Thursday.
&&
.AVIATION /00Z Friday THROUGH Tuesday/...
VFR will persist through the TAF cycle, but the one fly in the
ointment is a weak cold front crossing the region late tonight
which will bring 3 to 5 thousand foot cigs to northern parts of
the region closer to Lake Erie and a few showers and possible
rumbles of thunder. The best chance to see precipitation is at
CLE, YNG, and ERI, but it is also possible at TOL and CAK, just
less of a chance so not included in the TAF. Any shower or
thundershower would be brief and could lead to brief MVFR before
returning to VFR. Dry conditions will quickly return everywhere
Friday morning.
W to WNW winds will diminish to 5-10 knots this evening and also
back to SW tonight ahead of the front before veering W to WNW
again Friday morning into the afternoon and slightly increasing
to 7-12 knots.
Outlook...Non-VFR possible again with isolated to scattered
showers and thunderstorms on Saturday and Sunday.
&&
.MARINE...
Have allowed most of the Small Craft Advisory to expire, though will
hang on to the far east portion of Lake Erie through 8 PM, given
westerly winds of around 15 knots. Otherwise, not anticipating any
marine headlines through Monday, given flow will be generally south
to southwesterly, 10 to 20 knots. Slightly enhanced southwesterly
flow of 15 to 20 knots will arrive across the lake on Sunday ahead
of a cold front. Winds will shift towards the west, then northwest
Sunday night into Monday, but winds will decrease into the 5 to 10
knot range.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Sullivan
NEAR TERM...Garuckas/Sullivan
SHORT TERM...Kahn
LONG TERM...Kahn
AVIATION...Garuckas
MARINE...Kahn
Area Forecast Discussion
National Weather Service Des Moines IA
634 PM CDT Thu Jul 21 2022
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Thursday/
Issued at 309 PM CDT Thu Jul 21 2022
Key Messages:
-Heat Coming Back, More Intense Friday and Saturday
-Thunderstorms Late Tonight and Early Friday
-Thunderstorms Saturday, and Multiple Rounds Next Week
Discussion:
Iowa remains downstream of the H5 ridge axis, keeping middle and
upper-level flow northwesterly. There are two areas of surface high
pressure, one has moved over the Ohio River Valley, the other is
currently pushing southeast out of the Northern Plains. Between the
two was some weak convergence that generated a few cumulus clouds in
central Iowa this morning with very light rain. There is a weak cold
front moving ahead of the surface high pressure system across Iowa.
Temperatures are only dropping a few degrees behind it. The main
notable difference is the shift to northwesterly winds. However,
with the clear skies allowing for insolation during the afternoon,
temperatures have still be on rise this afternoon. The overnight
southwesterly winds help set the stage for this as well. For the
rest of this evening, expect clear skies to continue. A few cumulus
clouds may pop up along the cold front, but current GOES-16 visible
imagery does not show much in the way of development. There is a
subtle short-wave over the Front Range that this evening is expected
to start lee cyclogenesis. This will set the stage for a weekend
with hot, and potentially wet, weather.
Convection is expected to initiate later this afternoon over the High
Plains and Central Plains of Nebraska along with this short-wave.
This convection will move eastward during the evening and overnight
hours as the vorticity maxima ejects eastward. The first question,
is if this convection will hold together and congeal into a mature
MCS as a LLJ develops across the Missouri River Valley and areas
eastward. The deterministic GFS has continued to depict this kind of
solution, and keeps the system moving across the entire forecast
area. However, members of the GEFS have mixed signals. Several
members are showing the initial convection dissipating over eastern
Nebraska, but new development occurs in western Iowa with the
approach of the short-wave. There will be enhanced Q-vector
convergence with this feature, that may provide enough forcing. 12z
CAM guidance appears to be in more favor for a redevelopment
scenario, rather than having a massive MCS develop. Both of these
scenarios leave western Iowa with the best chance for rain showers.
Most of this activity will start after 06z tonight. Therefore, the
highest POPs are concentrated along and west of Hwy. 71. If the LLJ
remains strong enough past 09z, convection may continue going into
the mid-morning hours of Friday, and make it to around the
Interstate 35 corridor. The general trend in CAM guidance this
morning is to dissipate the remnants after 12z as it moves east of
Interstate 35. The deterministic GFS is the only solution that keeps
higher QPF going later into the early afternoon. As for the severe
threat, the low-level inversion will limit any near surface-based
parcels. Convection will be rooted above 850 mb being forced by the
low-level jet. RAP soundings though are showing steep lapse rates
from just below 700mb to around 500mb. Lapse rates are around 8.0
C/km, and effective shear for elevated storms may be around 35 kts.
This may support a threat for quarter size hail. A damaging wind
gust would not be out of the question, but heavy precipitation
loading would likely be needed to punch through the stable boundary
layer. If the convection lasts for an extended period of time, most
of it should be done after 18z Friday. During the afternoon, the
short-wave will pass through, but the surface feature will likely be
left behind. Another short-wave develops that may phase and help
deepen the surface cyclone. As a result, stronger southwest flow
develops ahead of the system, and will provide strong theta-e
advection into Iowa. This will will send temperatures back into the
90s across central and southwestern portions of the forecast area.
This may not reach the eastern and northeastern portions of the
forecast area by the afternoon, which will keep temperatures
slightly cooler.
Saturday, the second short-wave quickly ejects across the Central
Plains. An elongated surface low develops with this, with two local
pressure minima. Ahead of this, the warm front surges northward.
Yesterday, there was a decent amount of spread with respect to how
far north the warm front traveled before stalling. This morning,
there is better agreement that the warm front will surge to around
Interstate 90 in southern Minnesota. This will put most of our
counties in the warm sector of this system. This boundary will
eventually stall in the afternoon, with a surface high pressure
being forced southward out of Canada due to a strong closed-low
system over Hudson Bay. Consensus among individual ensemble members
is also higher in this northward placement of the warm front. The
shower and thunderstorm potential though is not overly
straightforward. While GEFS and other ensemble suites have over 80
percent probability for for accumulating precipitation within 24
hours across most of the forecast area, how many rounds of
convection that occurs is not consistent. With the warm front
surging overnight, theta-e advection will start early in the morning
on Saturday. This push of moisture may allow for stronger isnetropic
ascent, and elevated convection may develop on Saturday morning.
Therefore in the forecast, have placed widespread slight chances for
areas that will enter the warm sector during the morning. If
elevated convection does develop, most of this should dissipate by
the afternoon. The wind shear does not look overly impressive for
any elevated stuff Saturday morning. However, Saturday later in the
afternoon this changes. As the H5 short-wave approaches, deep layer
shear will be on the rise, and close to the boundary 0-6km values
around 50 kts. The ambient warm sector may see 30-40kts about 50
miles south of the boundary. As the high drops south of out Canada,
the stalled boundary will also be forced south, and will serve as a
cold front across the region. Yesterday, the capping looked very
strong across the ambient warm sector, and even in close vicinity to
the boundary. Today, guidance has decreased the MLCIN some. while
increasing the strength of the convergence. Therefore, the threat
for thunderstorms and potential for severe thunderstorms has
increased for Saturday evening. This is highlighted by the SWO Day 3
Slight Risk. An Enhanced Risk exists northeast of the forecast area.
Most of the severe risk is focused along the boundary, as this is
also where surface pressure falls will be strongest throughout the
afternoon. While a cap is a potential source of limitation, the
bigger one may actually be lingering convection and cloud debris
from morning elevated convection. The GFS is hinting at decreased
instability in the ambient warm sector, with MLCAPE values only
around 1000 J/kg. There is still a ribbon of MLCAPE over 3000 J/kg
directly along the boundary. Perhaps if theta-e advection is strong,
there may be enough to overcome the lack of insolation should clouds
stick around. If deep convection is hindered in the afternoon, the
push of the front across the area should be enough for widespread
showers late Saturday and continuing overnight into Sunday Morning.
Severe threat in this scenario would be low. Aside from the severe
convection, heat indices may also become a concern. The strong push
of WAA will send temperatures at least into the lower 90s. If the
warm sector clears during the afternoon, air temps in the upper 90s
are possible in central and southern Iowa. This would send heat
indices to near 105. However, morning convection may hinder this.
Because of the convection potential, have held off for issuing any
heat related headlines today for Saturday. However, be prepared for
excessive heat on Saturday afternoon.
Extended:
Although the flow will be zonal several times, a number of PV
anomalies will send multiple vort maximums across the upper Midwest
for this upcoming week. At this time, it is hard to pinpoint exact
timing of precipitation. Somewhere in Iowa will have a slight chance
of rain showers each day Sunday through Wednesday. The severe threat
will be better determined at a later time. Temperatures will be
average to just slightly warmer. Periods of showers may provide
relief from the heat.
&&
.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 624 PM CDT Thu Jul 21 2022
VFR expected through the TAF period with locally MVFR possible
from thunderstorms. There remains uncertainty regarding the
longevity of thunderstorms so left VCTS for short duration in
western terminals for early Friday.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Krull
AVIATION...REV/Jimenez
Area Forecast Discussion
National Weather Service Quad Cities IA IL
616 PM CDT Thu Jul 21 2022
...AVIATION UPDATE...
.UPDATE...
Issued at 453 PM CDT Thu Jul 21 2022
While convection along the primary surface cold front continues to
struggle, we`ve developed a few shallow convective showers over
locations in far eastern Iowa, well west of the cold front. This
is where dewpoints have not yet dropped from the 70s, and we`re
getting to use some of this CAPE present, though the fast movement
and small updrafts are unlikely to result in more than a brief
heavy showers. I`ve updated pops for these showers and weak
t-storms through 7 PM.
ERVIN
&&
.SYNOPSIS...
Issued at 300 PM CDT Thu Jul 21 2022
Shortwave is traversing northeast IA, southern WI with a vort max
moving into far northwest IL at 2 PM. Day cloud phase satellite
depicts more robust cumulus and isolated convection developing
far northwest IL into southern WI. A much more subtle shortwave
denoted by some mid cloudiness was traversing our southern cwa.
At the surface, a cold front extends from near a Dubuque to
Fairfield line. Temps across the area at 2 PM were in the upper
80s to lower 90s, with heat index readings in the mid/upper 90s
in areas ahead of the front.
&&
.SHORT TERM...(Through Friday)
ISSUED AT 300 PM CDT Thu Jul 21 2022
Key Messages:
1) Isolated shower/storm possible northeast late this afternoon.
2) More comfortable humidity tonight.
3) Chance for showers and storms Friday.
Discussion
Will have the potential to develop isolated/widely scattered
convection over the next couple of hours, mainly over our
NW Illinois counties, within zone of PVA amidst a moderately
unstable and uncapped atmosphere. Water vapor imagery does show
a lot of dry air and so this entrainment may lead to some
struggle with updrafts, hence any coverage remaining rather
sparse. If a storm gets going, can`t rule out some gusty winds
with advection of steeper mid level lapse rates, inverted V
soundings, and DCAPE 1300+ j/kg. Better potential in terms of
convection and any isolated severe threat could remain more
north/east of cwa. Further south, a very subtle mid level impulse
will continue slide through our far southern counties. This
region looks to remain capped and in absence of stronger lift
likely will remain dry.
After the front moves through, northwest winds will begin to
usher in drier dew points (mid 50s to lower 60s upstream into
northern and central IA as evidence). This should result in a
more comfortable night with lows in the 60s. Satellite and HRRR
smoke model indicate potential for some thin haze/smoke layer
moving in this evening south/west, but nowhere as thick as what
we observed last evening.
Late tonight, another wave approaches in west/northwest flow
and is likely to spawn some convection in one or more clusters
upstream of our area. This activity is likely to slide southeast
and weaken but move across portions of the cwa Friday AM with
a veering weak nocturnal LLJ and attendant elevated warm air
advection. Have kept PoPs in the lower chance category for now
due to the anticipated weakening nature, but this will need to
be monitored. Some redevelopment may occur Friday PM, particularly
north of I-80, in the elevated warm advection ahead of a surface
warm front. Confidence remains low on severe weather due to
potential AM precip and debris clouds, but if some organization
can occur with any storms, then strong wind gusts would be possible.
Highs tomorrow likely to range from the mid/upper 80s north to
the lower 90s. Heat index readings could reach into the upper 90s
to near 100 across far southeast Iowa and northeast Missouri.
.LONG TERM...(Friday Night through Thursday)
ISSUED AT 300 PM CDT Thu Jul 21 2022
Key Messages:
1. Potential for heat indices on Saturday to be over 100.
2. Several rounds of showers and storms Friday night through
Thursday.
3. There is a marginal or level 1 risk for severe storms Friday
night. There is a slight or level 2 risk for areas north of
Interstate 80 on Saturday afternoon and evening with a marginal
risk to the south.
Discussion:
Models vary through the long term period on the key details of the
forecast but there is good agreement in the large scale pattern. The
overall 500 mb synoptic pattern through the period will continue
ridging over the southwestern US and low pressure across southern
Canada placing the area under an active northwest flow aloft. This
will allow several shortwave to move across parts of the area
through the period.
An MCS is forecast to develop Friday night to our northwest with the
development of the low level jet and potentially veer into our area
overnight. Models disagree on where this feature will track across
the Upper Midwest with some models bringing it into our area. Due to
this potential, there is a marginal or level 1 risk for severe
storms Friday night across the entire area with the potential for
hail and damaging winds. Models show increasing precipitable water
values overnight in the 1.0 to 1.25 inch rain so there is the
potential for heavy rain.
Depending on where the MCS tracks Friday night will impact the
forecast for Saturday as any morning clouds and storms would impact
the temperature forecast. Currently, there is the potential for some
clouds to overspread the northern half of the area during the
morning into the afternoon. Models show strong warm air and moisture
advection through the day with air temperatures warming into the 90s
from north to south across the area. Dewpoints will increase into
the lower to mid 70s producing heat indices across the area of 100
to 105. This is solidly in heat advisory criteria and a headline may
need to be issued in later forecasts to account for the hot and
humid conditions across the area on Saturday.
These warm temperatures and increasing humidity will provide ample
fuel for thunderstorm development ahead of a shortwave trough
dropping southeastward across the western edge of the trough.
Currently, this shortwave will arrive during peak heating with storm
development expected to our northwest. Models show very high CAPE
values in the 3000 to 4000 J/KG along with deep layer shear of 30 to
40 knots. Currently storms to our northwest our forecast to congeal
into a southeastward propagating line and move across eastern Iowa,
northwest Illinois, and far northeast Missouri. The may threats will
be hail and damaging winds as well as heavy rainfall with
precipitable water values increasing to around 1.75 inches by
Saturday night. For these reasons, the storm prediction center has
placed a slight or level 2 risk for severe thunderstorms along and
north of Interstate 80 with the remainder of the area in a marginal
or level 1 risk.
Behind this system, the very warm and humid air will be pushed
slightly to our south for Sunday through the remainder of the
period. The current forecast has high temperatures in the lower to
mid 80s through the remainder of the period with low temperatures in
the 60s. However, the pattern will remain active with daily chances
of showers and storms as shortwave pass across the area each day.
There will be dry periods but they are hard to pin down resulting in
broad brushed chances through the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 612 PM CDT Thu Jul 21 2022
An isolated shower is possible in northwest Illinois through 7 PM.
A period of VFR weather with light northwest winds will be most of
tonight, but towards morning, the front that moved by today, will
return as a warm front, possibly with a cluster of storms passing
through in the 12Z to 16Z window. This remains low confidence, and
will retain the Prob30 thunder forecast. Otherwise, a return to
VFR south winds will be expected by Noon Friday.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...Ervin
SYNOPSIS...McClure
SHORT TERM...McClure
LONG TERM...Cousins
AVIATION...Ervin
Area Forecast Discussion
National Weather Service Grand Rapids MI
1137 PM EDT Thu Jul 21 2022
LATEST UPDATE...
Update
.UPDATE...
Issued at 1135 PM EDT Thu Jul 21 2022
Our convective event is just about cleared Southwest Michigan.
The storms causing some power outages in parts of Kent, Allegan,
Kalamazoo, Calhoun and Jackson Counties, likely caused by the
gusty winds, locally heavy rain, some small hail. Behind the storm
skies are clearing and should stay clear overnight. That is due
to some ridging both surface and aloft as the shortwave that
caused the convection this evening moves out. There is enough
winds in the boundary layer to keep any widespread fog from
developing.
Friday will see the surface ridge axis pass through our area ahead
of the next system. Most of the day should be warm and dry. The
RAP and HRRR suggest dew points could fall into the 40s by mid
afternoon Friday while air temperatures rise into the mid to upper
80s. That results in RH values below 30 percent and given winds
will be gusting to 20 mph in the afternoon, that would increase
the danger for wild fires.
&&
.DISCUSSION...(This evening through next Thursday)
Issued at 257 PM EDT Thu Jul 21 2022
...Risk for a few thunderstorms this evening...
A 850/700 mb trough dropping southeastward through WI is forecast
to track through the CWA this evening. Surface based instability
values of around 1000 to 1500 J/kg exist out ahead of this
feature...especially toward Holland and Kalamazoo. Forecast
soundings show an inverted V look to them and DCAPE is over 1000
J/kg. These two parameters/features support strong wind gusts
with any stronger cell. Forecast low level convergence favors the
area generally south of a Muskegon to Grand Rapids line for the
most shower/storm activity. This is where we will feature the
highest POPs.
...Additional showers and thunderstorms possible late Friday
night...
The latest runs of the models appear to focus the main storm
activity just southwest of the CWA late Friday night. The low
level jet and stronger instability is shown to be aimed in those
locations. Still...some deep moisture and weak instability is
shown for southwest parts of the CWA which will allow for at least
scattered showers and thunderstorms. Close monitoring will be
needed going forward as a northward shift of the low level jet and
instability could lead to an increase in the storm coverage for
the CWA.
...Numerous showers and storms look likely for Saturday night into
early Sunday...
An unseasonably strong mid to upper level wave will be tracking
eastward through the Canadian Prairies and into Ontario. On the
south side of this feature...the mid to upper level flow
strengthens over the Great Lakes Region. At the same time a strong
southwesterly low level jet will be moving into the Great Lakes
Region and advecting in abundant moisture. Deep layer shear will
be quite strong through the night. As a result of all this...one
or more MCS`s look possible in this window with an increased risk
for severe weather. In addition with PWAT values forecast to climb
up over 1.75 inches locally heavy rain is likely. If the storms
repeat over the same area...some flooding may occur. The low level
jet and instability gradient shift south and east of the CWA by
18z Sunday so much less in the way of storm coverage is forecast
by then.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 749 PM EDT Thu Jul 21 2022
There will be thunderstorms at most of our TAF sites this evening.
Due to the dry sub-cloud layer gusty winds are likely with these
storms so I put at TEMPO group in the TAF with wind gusts near 30
knots to allow for that. Expect brief IFR visibilities with these
storms as they do have intense rain cores. Some hail should be
expected with the stronger storms as well as the typical shifting
wind field and frequent lighting. The storms should be out of this
area by 10 pm or so. The rest of the night should feature skies
clearing and winds light from the west or west southwest, mostly
under 10 knots.
Friday should see VFR conditions all day but another shortwave
may bring clouds in late in the day. Winds may become gusty by
afternoon as a result of the shortwave moving closer to the area.
Any storm would be after 00z but I expect most of those should be
south of our TAF sites (we will watch that through).
&&
.MARINE...
Issued at 257 PM EDT Thu Jul 21 2022
The pressure gradient tightens up across the northern zones later
Friday into Friday night as a wave of low pressure tracks eastward
through the northern Great Lakes Region. Southwesterly winds will
increase...especially for Little and Big Sable Points by Friday
evening. Hazardous conditions for small craft and swimmers may
develop.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...WDM
DISCUSSION...MJS
AVIATION...WDM
MARINE...MJS
Area Forecast Discussion
National Weather Service Northern Indiana
748 PM EDT Thu Jul 21 2022
.SYNOPSIS...
Issued at 254 PM EDT Thu Jul 21 2022
Warm but less humid conditions will be in store on Friday. Heat
and humidity will build for the weekend with peak afternoon heat
indices in the mid to upper 90s expected on Saturday. Slight
chance of showers and thunderstorms are possible this evening.
Periodic chances of showers and storms will follow for Friday
night through the beginning of next week.
&&
.UPDATE...
Issued at 747 PM EDT Thu Jul 21 2022
Continuing to monitor convection from west of KGRR SW to over S Lk
MI back to north of the Chicago metro area. A few of the storms
have attempted to organize with one in particular over mid lake
(and now dropping ESE towards South Haven) exhibiting transient
supercell characteristics, semi deviant in its overall motion at
times (E then SE then back to E) and likely produced severe level
winds over the lake. Exactly how these storms will continue to
unfold is still uncertain, but HRRR still seems closest to reality
with current setup so tending to lean somewhat towards it. If it
is to be believed, convection should continue to drop SE and may
expand somewhat as it runs into at least 1000 to maybe 2000 J/KG
of CAPE still in place after dark. While severe threat still
likely minimal will monitor trends. As for pops, at this point
will clean up a bit to adjust timing, but keeping in slgt chc to
chc for now to see if everything holds together or even expands
some.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 254 PM EDT Thu Jul 21 2022
Breezy conditions today will continue over the next several hours
ahead of a short wave originating from the northwest. The breezy
conditions continues to create moderate swim risk on Lake Michigan
beaches, earlier reports from Warren Dunes and Silver Beach
indicated 3 foot waves. This shortwave is moving through a northwest
flow aloft and will increase chances for some showers and even a few
thunderstorms later this evening. The best chances look to be the
more northern portions of our CWA however a few storms cannot be
ruled out further south. Any of the storms that develop are not
expected to become severe. Main threats would be gusty winds and
brief heavy rainfall, and of course dangerous cloud to ground
lightning. This shortwave will continue to move east to
southeastward through the area by late tonight. Winds will trend
lower with the exit of the disturbance. Precipitation amounts will
be minimal with the showers, locally heavier amounts would be
expected with any thunderstorms however.
&&
.LONG TERM...(Friday Night through Thursday)
Issued at 254 PM EDT Thu Jul 21 2022
Temperatures will trend higher over the next couple of days with a
westerly to northwesterly flow in place and synoptic heights
slightly increasing on the northern periphery of an elongated ridge
over the mid south. The hottest day will be on Saturday with highs
ranging in the upper 80s to low 90s. Surface moisture will also
increase on Saturday with dew points in the upper 60s to lower 70s.
This will make Saturday a bit uncomfortable with heat indicies in
the mid to upper 90s.
Several more disturbances will move through the quasi-zonal flow
aloft over the next several days bringing periods of increased
chances for showers and thunderstorms. Saturday will have decent
surface moisture along with ample surface warming. A disturbance
moving through will provide enough instability and lift to bring a
decent chance of thunderstorms. Shear may be the limiting factor.
Will have to keep an eye on that. SPC currently has our entire area
under a marginal risk for severe storms on Saturday.
A Hudson Bay trough will push lower heights southward beginning
Sunday bringing relief in the form of a cooling trend. Sunday high
temperatures will be slightly cooler than Saturday with highs in the
mid 80s and low 90s. But on Monday and Tuesday high temperatures
will be noticeably cooler with highs in the upper 70s to lower
80s. Precipitation chances look to remain increased with the zonal
flow firmly in place continuing to bring western Canadian
disturbances through the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 747 PM EDT Thu Jul 21 2022
Focus of TAFs (mainly at KSBN) remains on non-zero threat for
isolated convection over the next couple of hours. Been tracking
widely sct showers/storms which now extend from south of KMKG to
over S LK MI to N of KORD. These will continue to track ESE with
a few cells in far SE WI to over the SW part of the lake possibly
taking aim on KSBN. Despite how the radar looks, confidence quite
low on will it impact the site and if so how strong will it be.
Enough signals to introduce a VCSH mention with maintenance of
VFR conditions for now. Given the isolated nature any impacts
would encompass a very narrow wind which will diminish the later
we go. If coverage/intensity expands will amend accordingly. Have
left KFWA dry as even lower confidence anything makes it to the
site and it it does most likely will be a high based shower.
Once this threat has passed, VFR conditions to dominate with a
shift to NW winds behind the front.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...Fisher
SYNOPSIS...Andersen
SHORT TERM...Andersen
LONG TERM...Andersen
AVIATION...Fisher
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Area Forecast Discussion
National Weather Service Lake Charles LA
845 PM CDT Thu Jul 21 2022
.UPDATE...
Heat advisory expired at 7 PM this evening as temperatures and
heat index values decreased across SE TX. Current temperatures are
running a little cooler than expected thanks to increased clouds
across the region as well as a few cooling showers earlier today.
Despite this, overnight lows are still on track to reach the
middle and upper 70s.
KLCH radar shows convection has diminished considerably, with
just a couple of small isolated showers remaining in the CWA.
Expect generally quiet conditions overnight. Convection occurring
near the AR/LA border a few hours ago has also decreased, with the
more intense activity now propagating toward central MS. Some
models suggest that some of this convection, while becoming
weaker, could hold together as it moves southward then
southwestward toward central LA late tonight. However, 00Z HRRR
guidance is downplaying this scenario (waiting on 00Z HiRes as of
this writing). At this time, no changes to the forecast are
anticipated, other than adjusting hourly temperature and dewpoint
grids to reflect obs/trends.
24
&&
.PREV DISCUSSION... /issued 524 PM CDT Thu Jul 21 2022/
DISCUSSION...
For the 07/22/2022 0000 UTC TAF package.
AVIATION...
Radar showing scattered TSRA over Acadiana region, will keep the
VCTS through 01z when they are expected to diminish. Elsewhere,
TSRA likely over for the day, thus took out VCTS for AEX, BPT,
LFT. Otherwise, South to southwest winds will diminish after
sunset, and pick up to near 8-10 kts after 15z Friday. Slightly
higher SHRA/TSRA chances over Acadiana region, thus will introduce
VCTS for ARA/LFT by 18z. With the higher chances of SHRA/TSRA
Friday, VCTS introduced by 15z.
08/DML
PREV DISCUSSION... /issued 353 PM CDT Thu Jul 21 2022/
SHORT TERM [Tonight through Saturday]...
A bit of an impulse made its way around the upper level ridge and
produced cloud cover and shower activity across the northern zones
earlier today. This activity has pretty much dissipated, however
the left over cloud cover and the late start on max daytime
heating has kept heat index readings in check over that area.
Scattered showers and thunderstorms are now developing further
south with the sea breeze and this activity will continue until
sunset and then diminish. Heat Advisory for southeast Texas will
also continue until 7 pm local. The lack of convection for those
zones along with anomalously high Gulf moisture made for
oppressive heat index values between 108 and 112 degrees that will
persist in spots away from any cooling showers for another couple
of hours.
On Friday, the upper level ridge will break down briefly across
the forecast area. This will allow a surface boundary to come down
to just north of the forecast area from the north, and a mid
level inverted trough and moisture surge to move in from the east.
The combination of the two should allow for the best chance for
showers and thunderstorms this week. Still some question to when
the best coverage will be, some hi res guidance showing a MCS
feature for the morning, while others should activity waiting to
develop until the afternoon. Probably the truth is in between
with some activity for the northern zones in the morning and the
remainder of the area in the afternoon.
The convection and cloud cover on Friday will help keep the heat
in check and not seeing any heat index readings near heat advisory
criteria.
PWAT values on Friday will be in the 2.0 to 2.25 range with mean
layer RH from the surface to 50H over 70 percent. So there could
be some heavy rainfall with the stronger convection. The area has
been dry and could take some rainfall, however, there is a
Marginal Risk for Excessive Rainfall on Friday from WPC, mainly
if the high rainfall rates fall over urban poor drainage areas
some street flooding could occur.
On Saturday, the upper level ridge begins to build back to the
east and allow for a typical summer time day, with diurnal
convection.
Rua
LONG TERM [Sunday through Thursday]...
Upper level ridging will become broadly centered from north Texas
across Oklahoma and Arkansas Sunday and Monday. This is expected to
keep afternoon convection and cloud cover limited across central
Louisiana and interior parts of southeast Texas which will allow
afternoon highs to once again flirt with or exceed triple digits.
Closer to the coast, scattered, diurnally driven, convection will
keep temperatures closer to seasonal normals, but mid 90s will be
possible across areas that do not see afternoon storms.
An inverted trof will slide from east to west across the northern
gulf beginning Tuesday through the middle of the week providing
upper level support for more widespread convection especially closer
to the coast. The upper ridge north of the region will also begin to
push off to the east Wednesday allowing more substantial precip
coverage across central Louisiana. This should aid in bringing
temperatures back to more seasonal values.
Jones
MARINE...
Typical summertime pattern looks to be in place during the
forecast period. A surface high will be centered east of Florida
and ridge across the northern Gulf of Mexico and into the coastal
waters. This will result in a light to occasionally moderate
onshore flow, with mainly low seas.
There will be a daily chance of showers and thunderstorms, mainly
nearshore in the late morning and afternoon, and offshore late at
night into the morning.
Rua
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Paducah KY
621 PM CDT Thu Jul 21 2022
.UPDATE...
Issued at 620 PM CDT Thu Jul 21 2022
Updated aviation discussion for 00Z TAFs.
&&
.SHORT TERM...(Tonight through Saturday night)
Issued at 333 PM CDT Thu Jul 21 2022
Temperatures have underachieved today, but dewpoints have held in
the middle 60s over most of the region. The less hot conditions
today make the expected warming for Friday a little more extreme,
on the order of 10 degrees, which may be a little harder to
swallow.
The upper ridge is coming back Friday, but the surface ridge will
still be cutting north to south right through the middle of the
region. This will keep south winds from kicking in much, even in
the west, which will hold back the humidity and possibly the
temperatures. We stuck close to the NBM for temperatures and went
with a mix of the ConsShort and NBM dewpoints. The result yields
max afternoon heat indices from 103-106 over most of southeast
Missouri and adjacent portions of southern Illinois and west
Kentucky. After collaboration with WFO SGF, LSX, and MEG we decided
to issue a Heat Advisory for Friday for that area.
The HRRR actually develops some widely scattered convection over
much of Missouri Friday afternoon and evening, including near our
Ozark Foothills region. Given the uncertainty in the temperature
and humidity increases in that area, it is hard to believe there
will be any tangible convection there. We will keep the forecast
dry, but will keep a wary eye on the convective possibilities.
The upper ridge will continue to build overhead Saturday and south
southwest winds will kick in throughout the area. Confidence is
much higher for heat and humidity to return over the entire area,
with max afternoon heat indices reaching the 104-111 range. Much
of the region will see high temperatures in the upper 90s to lower
100s, with the hottest conditions expected over southeast
Missouri. While the humidity will be increasing we are not seeing
any evidence that it will as nasty as we experienced yesterday. A
Heat Advisory has been issued for the entire area Saturday and
with similar conditions forecast for Sunday, we decided to run it
through the entire weekend.
Low temperatures will trend warmer through the period. Tried to
lean a bit to the low side for lows tonight and Friday night, but
with south winds and humidity returning Saturday, Saturday night
will be quite mild with lows in the mid to upper 70s expected.
.LONG TERM...(Sunday through Thursday)
Issued at 333 PM CDT Thu Jul 21 2022
The latter half of the weekend will be clear to partly cloudy and
sultry under a flat ridge of high pressure aloft, with highs 95 to
103 and heat indices 100 to 110 (110 possible west of the MS River).
A heat headline should still be in place for Sun into the early
evening.
The approach of a surface cold front from the north and its
associated shortwave energy aloft will increase the probability of
showers and tstms developing progressively farther south in the
moist and increasingly unstable airmass Sun night. By Mon, PoPs will
increase to 40-50% as the front sinks farther south into the PAH
forecast area. The front is expected to stall sometime on Mon and
eventually make its way north, but additional ripples in the mid
level flow are expected to act on the moist and unstable airmass,
keeping healthy PoPs for showers/tstms in the forecast, mostly
during the days and evenings. There are some model indications that
Wed could offer up a brief reprieve in the scattered activity
between shortwaves, but at this time frame, differences exist in the
medium range model solutions with timing and evolution of these
shortwaves, thus we will keep a 35-45% PoP in for Wed/Wed night.
The models suggested, with some timing differences, that a larger
mid level shortwave and attendant surface cold front may move into
our region on Thu (Day 7) providing a solid chance of showers/tstms.
Temps are expected to cool somewhat by Mon with the increased cloud
cover and scattered pcpn, with highs in the upper 80s common in
southern IL/southwestern IN Mon and Tue, with 90s in southeastern MO
and parts of western KY. Wed may possibly provide an uptick in
highs, with 90s experienced across the entire region. Heat indices
of over 100 are possible. If the forecast holds, Thu could be a bit
cooler by a few degrees.
&&
.AVIATION...
Issued at 620 PM CDT Thu Jul 21 2022
VFR conditions will persist through Friday. Near calm winds
tonight should become predominantly southwest to west at or below
5 knots on Friday.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory from 11 AM Saturday to 8 PM CDT Sunday for
ILZ075>078-081>083-085>087-089>091-094.
Heat Advisory from noon Friday to 8 PM CDT Sunday for ILZ080-084-
088-092-093.
MO...Heat Advisory from noon Friday to 8 PM CDT Sunday for MOZ076-086-
087-100-107>112-114.
IN...Heat Advisory from 11 AM Saturday to 8 PM CDT Sunday for INZ081-
082-085>088.
KY...Heat Advisory from 11 AM Saturday to 8 PM CDT Sunday for
KYZ001>003-005>022.
Heat Advisory from noon Friday to 8 PM CDT Sunday for KYZ004.
&&
$$
UPDATE...RJP
SHORT TERM...DRS
LONG TERM...DB
AVIATION...RJP
Area Forecast Discussion
National Weather Service Pocatello ID
207 PM MDT Thu Jul 21 2022
.SHORT TERM...Tonight and Friday. We continue to watch for the
ridge to break down over the next 24 hours. Limited monsoon is
still expected to kick off a few thunderstorms across the Albion
Mountains and southeast highlands through midnight. We aren`t
expecting much other than some sprinkles and gusty winds if
something can sustain itself long enough to produce even that.
While the potential is almost zero, it is still NOT zero across
portions of the central mountains on the northern end of the
moisture push. There will at least be some continued cloud
buildups. We should see any potential for showers and storms
ending overnight. For tomorrow, the low offshore weakens and lifts
across the Panhandle. The biggest risk we will see comes from
gusty winds and drier air. At the moment, we aren`t seeing enough
wind for any type of Lake Wind or Wind Advisory headlines. There
should still be enough monsoon moisture for isolated storms along
the Montana border and also across the Albion Mountains and
southeast highlands. We might see a few storms across the
southeast corner produce some light rain and gusty winds.
Temperatures will be similar vs today across most of eastern
Idaho, although it looks like western locations will be just a
couple of degrees cooler. Keyes
.LONG TERM...Saturday through Thursday. Saturday looks a bit
cooler with any gusty winds confined to the Arco Desert and also
the ridgetops of the central mountains. We MAY see a storm or two
across the eastern and southeast highlands, but chances are
really, REALLY low. Another weak storm crosses the state, with an
uptick in wind and also the potential for isolated storms across
the southeast corner. Beyond that, we actually will be under
northwest flow as high pressure rebuilds to our west. We may see a
few storms from time to time around Island Park or along the
Wyoming border as storms clip eastern Idaho. Temperatures will
only be slightly warmer next vs what we will see over the weekend. Keyes
&&
.AVIATION...For the 18Z TAFS through 18Z Friday.
Upper level ridge overhead and will gradually begin to fill in as a
FEW/SCT deck across the South Hills and Southeast Highlands this
afternoon expanding to the Central Mountains and Eastern Highlands
by this afternoon. Convective clouds building in this afternoon will
lead to a SCT/BKN deck over the mountainous terrain with showers and
thunderstorms along the Utah border region just like yesterday south
of the Snake Plain, staying south of KPIH and KBYI. Winds will
remain less than 15 kts for all terminals with clear skies returning
after sunset. The breakdown of this upper level ridge feature falls
tomorrow with stronger afternoon winds being the primary concern.
The latest HRRR smoke guidance shows continued smoke impacts aloft
from the Moose Fire burning locally in the Salmon-Challis NF,
reducing visibility at the surface and especially aloft at times
throughout the day. If flying through the Lemhi Range to Salmon
visibilities could be reduced to less than 4 miles. Stronger S/SW
winds tomorrow will allow for improvements in smoke coverage as
smoke remains confined to Lemhi County and along the Montana border
north and east. MacKay/Preston
&&
.FIRE WEATHER...We are still expecting a classic ridge breakdown
pattern tomorrow across central and eastern Idaho. Ahead of that,
we are still looking for isolated dry storms this evening closer
to the Utah border in 427 and 413. Little rainfall and gusty winds
are possible. We are watching afternoon clouds across the central
mountains for any development, but so far nothing is happening.
Expect poor overnight humidity recovery across most of our
mountain fire zones...except for portions of 411 and 413 near the
Wyoming border. Values below 25% are forecast closer to ridgetop
across the central mountains and a good chunk of 411, 413 and 427.
For tomorrow, with the breakdown of the ridge...we will see
stronger winds developing. With humidity values already low and
potentially even a bit lower across most areas, we will see
widespread critical fire conditions over the central mountains and
across zones 425 and 410. We have converted the FIRE WEATHER WATCH
to a RED FLAG WARNING from 10am-9pm tomorrow. We will see pockets
of critical conditions across the rest of the area. We considered
a warning for Zone 427 and 413 but conditions should be isolated
enough to preclude that...for now. We will also be watching for
some isolated showers and storms tomorrow, mainly along the Utah
border in 427 and 413. The potential for wetting rains in those
areas is around 15% at best. We could also see a few storms along
the Montana border, but the most likely scenario is for storms to
remain in Montana. Saturday will be a bit cooler. We will see some
gusty winds across 410 and ridgetops. At the moment, gusts will
remain low enough to keep things out of Red Flag territory. While
chances are at best 10%, a storm could pop up along the Wyoming
border and around Bear Lake. A weak low crosses the state Sunday.
At the moment, the main risks may again come from the combination
of gusty winds and low humidity. Right now, it looks like we stay
BELOW threshold for Red Flag Warnings but we will be looking
closer at over the weekend. A few storms may fire again closer to
the Wyoming border with what monsoon moisture is around. Heading
into next week, it looks mostly dry but we will be under northwest
flow as high pressure reloads to our south and west. We may see an
occasional shot of thunderstorms around Island Park and the Wyoming
border. Keyes
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 10 AM to 9 PM MDT Friday for IDZ410-425-
475-476.
&&
$$
Area Forecast Discussion
National Weather Service Tallahassee FL
838 PM EDT Thu Jul 21 2022
.UPDATE...
Raised pops this evening and overnight along our western CWA
boundary as convection to the north has organized and is moving
southward. Questions remain on how strong it will be when it
reaches us and how much of this convection actually moves into our
area. Latest HRRR has much of the precipitation staying to our
west but enough probabilities remain to atleast bump rain chances
up a little. No other changes were needed for the tonight.
&&
.PREV DISCUSSION [739 PM EDT]...
.NEAR TERM [Through Friday]...
The widespread wet pattern that`s been in place across the region
is expected to continue at least one more day into Friday as a
weak upper level trough lingers over the area.
For the rest of this evening, much of the convective activity is
expected to reside across our Alabama and Georgia counties where
a weak boundary was noted around 3pm this afternoon. As noted by
the most recent WPC MPD (mesoscale precipitation discussion),
moist southerly flow south of this boundary and weak northerly
upper level flow aloft should at least lead to very slow
progression of this boundary north through the afternoon. This
could lead do a localized threat for flash flooding across our
AL/GA counties through the remainder of the afternoon and evening.
Additionally, the weak upper level trough helping to aid this
convection will slowly drift southeast through the evening as it
becomes increasingly elongated. This means convection across the
area this evening could linger into the overnight hours,
especially if stronger convection upstream of the area across
northern AL/GA remains organized into the evening hours as it
moves south. However, this largely depends on how the boundary
progresses through the overnight hours.
By Friday morning, storm coverage should gradually decrease but
with the weak boundary still residing to our north, we can`t rule
out isolated/scattered storms across our Alabama and Georgia
counties in the morning hours around sunrise. With southerly flow
expected to remain in place at the surface tomorrow, the best rain
chances will again be across AL/GA. With weakening upper level
flow, expect the potential for localized flooding again on Friday
with a moist airmass in place fueling high rain rates.
.SHORT TERM [Friday Night Through Saturday Night]...
A boundary across the region Friday night will weaken, however, with
it lingering around the area, it will help to keep some convective
activity persisting across the region into Friday night. Upper
level ridging begins to build into the tri-state area on Saturday
and this combined with slightly lower PW values (1.6-1.9 with
pockets of 2") will help to keep PoPs a little lower then what
we`ve seen lately, more in the 30-50% range. Some activity will
continue into Saturday night as a shortwave rounds the upper level
ridge. As the ridge builds into the region on Saturday, highs
will tick upward a few degrees into the lower 90s with lows in the
mid 70s.
.LONG TERM [Sunday Through Thursday]...
High pressure will continue to build into the region on Sunday with
a few perturbations in the flow. PW values will trend upward to 2+
inches and this will lead to more convection across the region on
Sunday compared to Saturday. High pressure will elongate west to
east north of the CWA next week and bring the deep layer flow more
to the east or southeast. The chance for showers and thunderstorms
will remain in the forecast each day. Expect highs in the lower to
mid 90s with lows in the mid 70s.
.AVIATION...
[Through 00Z Saturday]
Watching a developing area of convection in central Alabama
progged to move south with time this evening. Hi res guidance, of
varying degrees, does show movement into our CWA later this
evening. This area could be severe on arrival, or at the very
least, strong winds could accompany the storms at DHN or as far
east as ABY. Have tempos for convection later this evening.
Through the day Friday, convection will develop along the outflow
and perhaps back into southeast Alabama in the afternoon hours.
.MARINE...
Favorable boating conditions are forecast the next few days outside
of thunderstorms. Tranquil seas of less than 2 feet are expected
this weekend as initially southwest winds become light and variable
under the influence of surface high pressure. Southeast winds at
around 10 knots arrive late in the period.
.FIRE WEATHER...
Fire weather concerns should remain low for the next few days,
mostly in part due to the wet pattern we`ve observed lately. Drier
conditions with less chance for rain is expected over the weekend
along with warmer temperatures. With high pressure expected over
the weekend, dispersions will be on the lower side.
.HYDROLOGY...
Wet weather continues through Friday and as such, a Marginal Risk
(level 1 of 4) for excessive rainfall is in place over southeast AL,
bordering FL Panhandle counties, and southwest GA tomorrow. Reduced
rain chances are forecast this weekend thanks to a more typical
summertime pattern returning. Only localized flooding is a concern
from strong, efficient-rainmaking thunderstorms. Urban, low-lying,
and poor-drainage areas are most susceptible. The latest 7-day QPF
amounts are generally 1.5 inches or less. In terms of rivers,
Ochlockonee - Havana (US-27) is in action stage, but cresting and
expected to fall below by Saturday night.
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur (while following all local, state, and CDC guidelines) by
calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 74 92 73 94 74 / 10 50 10 40 10
Panama City 78 88 77 89 77 / 40 40 10 40 10
Dothan 74 87 72 90 73 / 40 60 20 40 10
Albany 75 90 73 92 74 / 20 60 30 40 20
Valdosta 73 93 73 94 73 / 10 50 20 50 20
Cross City 74 93 74 94 73 / 10 30 20 50 20
Apalachicola 78 88 76 89 77 / 20 20 10 30 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 2 AM EDT /1 AM CDT/ Friday for
Coastal Bay-Coastal Gulf-South Walton.
GA...None.
AL...None.
GM...None.
&&
$$
UPDATE...Scholl
NEAR TERM...Dobbs
SHORT TERM...Fieux
LONG TERM...Fieux
AVIATION...Scholl
MARINE...Fieux
FIRE WEATHER...Dobbs
HYDROLOGY...IG3