Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/25/23
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1101 PM EDT Sat Jun 24 2023
.SYNOPSIS...
It will be muggy tonight followed by a warm and humid day
Sunday with scattered showers and thunderstorms. Humid
conditions and unsettled weather will continue next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 1045 PM...Convection to the southeast of the Capital
District has developed into a line and has grow talk enough for
lightning. Some locally heavy rainfall is occurring. Activity
will continue to move eastward.
.PREVIOUS DISCUSSION [7:45 PM]...The steady precipitation has
exited the local area. Convection is firing up across Greene,
Albany and Rensselaer counties. The SPC Mesoscale Analysis
indicates SBCape of 1500 J/kg across the southern half of the
forecast area where we have had some sunshine. The HRRR has
captured the initiation of this convection. Have scattered
showers and isolated thunderstorms across the southern half of
our forecast area through the evening. Activity will diminish
with loss of heating. Otherwise, have made minor adjustments on
other parameters to better reflect current conditions and
trends. Muggy evening with dew points in the mid 60s to lower
70s and wet ground from today`s rain. Expecting fog and stratus
to form across the area tonight given the very light flow, wet
ground and high low level moisture.
PREVIOUS DISCUSSION [1:45 PM}...GOES16 water vapor imagery
shows the shortwave responsible for the rather widespread area
of rain that has impacted most of the region today is finally
lifting into northern New England. Regional radar show the back
edge of the rain is already exiting the mid- Hudson Valley and
the eastern Catskills and will continue lifting northeastward
through 18-19 UTC. Until then, areas from Albany north and east
will continue to see light to occasional moderate rain. MRMS and
NYS mesonet data show total rainfall amounts from this
shortwave have ranged 0.25 to 0.50 inches with locally higher
amounts up to 1 - 1.50 inches mainly in Columbia, Dutchess and
Rensselaer County where the deformation zone and pivoting rain
bands set-up this morning. Given the dry antecedent conditions
over the past few weeks, no flooding resulted.
Behind this shortwave, some limited breaks of afternoon sun
are possible due to subsidence in its wake. We trended POPs
downward after 18 UTC to show the drying trend which matches
latest CAM guidance. However, with such a humid environment in
place, any breaks of sun or thinning of clouds will likely help
fuel the development of additional showers and even isolated
thunderstorms so we maintained the forecast for isolated to
scattered thunderstorms for the afternoon. Given dew points
approaching 70 and PWATs in excess of 1.50", any storm will be
capable of producing brief downpours. Should afternoon
convection linger over areas that already experienced an inch of
rain this morning, some isolated flooding is not ruled out. We
will monitor radar trends through sunset. Otherwise,
temperatures have remained cool with many only in the upper 60s
to low 70s but depending on any breaks of sun or thinning of
clouds, temperatures should rise into the mid to potentially
upper 70s late this afternoon. Combined with dew points near 70,
it will feel even warmer/uncomfortable.
Heading into tonight, showers and storms should diminish once we
lose diurnal heating. Mid and upper level clouds are expected
to clear which could result in some low stratus or fog. There
are still some discrepancies among the guidance if and where any
stratus/fog develop but given elevated dew points and daytime
rainfall, we continue to show fog in the forecast, especially
after 06 UTC. Nighttime hours are quite limited in late June so
we only show fog for a few hours as once we the sunrises by 10
UTC, any fog should quickly diminish. However, forecast
soundings show a low level inversion developing so low stratus
could continue into the morning. Limited diurnal change in
temperatures expected due to such a moist/humid environment with
overnight lows only in the mid to upper 60s.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Sunday...The sfc reflection of the mid and upper level low will
be drifting east of the I-87 corridor during the afternoon.
Diurnally trigger showers and thunderstorms are possible again.
PWATs continue to be +1 to +2 STDEVs above normal. 00Z HREFS has
SBCAPEs widespread in the 1000-1500 J/kg range. However, the
deep shear is anemic at 10 KT or less. Some bursts of heavy
rainfall are possible and maybe a brook or creek may fill up.
Some ponding of water is possible on roadways. WPC continues a
barrage of "Marginal" risks of excessive rainfall to throw a
cautionary note for an isolated flash flood. Max temps at or
slightly above normal are possible to close the weekend with
highs 80-85F in the valleys and 70s to around 80F over the
higher terrain.
Sunday night...the shower and isold-sct thunderstorm activity
should fizzle prior to midnight and it will be a balmy night.
Lows will be in the mid to upper 60s in the valley areas, and
upper 50s to lower 60s over the higher terrain.
Monday...Like a broken record...the next bout of showers and
thunderstorms will arrive. This time a re-invigorated mid and
upper level low impacts the forecast area as it is centered over
the Great Lakes Region and Midwest. PWATS remain around 1.50" in
the +1 to +2 STDEVs range above normal. The showers will become
numerous to widespread by the afternoon with increasing low-
level theta-e advection ahead of the low and a frontal boundary.
Some of thunderstorms could produce burst of heavy rain again
with highs near normal with 70s to lower 80s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A warm, muggy, and wet weather pattern looks to continue throughout
the long-term forecast period. Near day-to-day chances of rain can
be expected over the forecast area. Monday night into Thursday,
forecast models and ensembles continue to depict/advertise a slow
moving, negatively tilted, occluding, triple point low pressure
system slowly tracking from the Midwest/Great Lakes Region into the
Northeast U.S. Southeasterly winds ahead of the low will aid in the
advection of moisture from the tropical Atlantic into an already
moisture-rich environment. With dewpoints in the 60s/70s and
precipitable water (PWAT) values 1-2 STDEVs above normal, periods of
rain are likely Monday night through at least Thursday as the low
slowly moves into the forecast area. The best chance and coverage
for rain will be during the afternoon hours or hours of peak
boundary layer (BL) heating. Some thunder is also possible during
the afternoon hours each day from Tuesday through Thursday if the
forecast model`s suggestion of increased instability values is
realized. Regardless, downpours is possible each day (Tuesday
through Thursday) given the saturated, tropical environment.
Thursday night into Saturday, forecast confidence decreases as most
of the deterministic models suggest a period of dry weather with the
low having departed to our east-northeast. However, some of the
ensembles suggest the potential for precipitation sticking around.
Will have to monitor these trends. For now, have low grade chance
PoPs Thursday night into Saturday. Beyond Saturday, forecast
models/ensembles are signaling at another storm system approaching
from the Midwest/Great Lakes Region Saturday night into Sunday that
could result in another period of rain Sunday into the early to mid
parts of the following week.
While it will be rather humid especially during the first half of
the long-term period (Tuesday through Thursday), temperatures will
run near normal levels during this period with cooler than normal
highs and warmer than normal lows thanks to ample cloud cover and
the incessant chances for rain almost every day. The normal high for
Albany during this time period is in the lower 80s. Forecast highs
are expected to mainly be in the upper 70s each day with lower 80s
cropping up by Friday/Saturday. Overnight low temperatures will be
mainly in the mid to upper 60s (50s higher elevations).
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
THROUGH 00Z MONDAY...Rain has significantly decreased across the
region leaving just a few pop-up showers scattered about. Ceilings
have come up at all terminals with the exception of KGFL where
cloud cover remains fairly dense and IFR ceilings still persist.
There has been some clearing as the shortwave disturbance that
brought on all of today`s rain continues to move away from the
area. However, visible satellite shows clouds filling back in in
places especially where some of the aforementioned showers have
developed.
Tonight`s forecast contains some uncertainty as models are
conflicted with just how much clearing will occur. With elevated low-
level moisture remaining present, any clearing would make it easy
for terminals to experience fog/mist. However, it is also possible
that the result of this low-level moisture could be
persistence/reinforcement of a low stratus deck. Due to
consistency in TAF guidance, included fog/mist in all of the
TAFs. KGFL and KPSF are the two terminals that could see
conditions representative of the LIFR category while KALB and
KPSF would likely only drop to IFR should fog/mist form. Will
continue to monitor trends and make amendments where necessary.
Tomorrow, lower clouds will likely persist through at least the
early morning; VFR conditions should return by late morning/early
afternoon. It is possible that some scattered showers and
thunderstorms develop tomorrow afternoon, but kept these out of the
TAFs for now as these could be sporadic in nature and would
likely only require brief TEMPOs should they impact any
terminals.
Winds will be turning from a more southerly direction overnight to
the northeast by tomorrow. Magnitudes of 2-4 kt can be expected.
Outlook...
Sunday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday: High Operational Impact. Definite SHRA...TSRA.
Monday Night: High Operational Impact. Definite SHRA...TSRA.
Tuesday: High Operational Impact. Breezy. Definite SHRA...TSRA.
Tuesday Night: High Operational Impact. Breezy. Definite SHRA...TSRA.
Wednesday: High Operational Impact. Definite SHRA...TSRA.
Wednesday Night: High Operational Impact. Likely SHRA...TSRA.
Thursday: High Operational Impact. Likely SHRA...TSRA.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...IAA/Speciale
NEAR TERM...IAA/Speciale
SHORT TERM...Speciale/Wasula
LONG TERM...Frugis
AVIATION...Gant
Area Forecast Discussion
National Weather Service La Crosse WI
701 PM CDT Sat Jun 24 2023
.DISCUSSION...(This evening through Saturday)
Issued at 245 PM CDT Sat Jun 24 2023
Key Messages:
- Thunderstorms increasing this afternoon and tonight. Severe
storm probability highest in parts of northeast Iowa and
southeast Minnesota (5 to 20%).
- Multiple rounds of storms - Locally heavy rain possible where
storms repeat over the same area.
- Landspout potential Sunday
Overview:
The morning WSR-88D radar mosaic was quite active with a decaying
mesoscale convective complex moving out of the Missouri River Valley
into parts of Minnesota and Iowa. The northern end of the
convection quickly dropped off with warming cloud tops, however the
southern end was more persistent through mid morning closer to the
instability and the edge of the cap. Numerous wind reports were
noted across southeast SD/southwest MN/northwest IA with 65mph wind
reports as late as 650am in Florence MN (Lyon Co.). Since then,
the winds have decreased with more recent gusts 15 to 30 mph with
pockets of 30 to 50 mph. At 19Z...Convection was increasing across
central Iowa.
Water vapor satellite imagery and heights showed a large closed low
over the Dakotas into Montana with diffluent flow into MN/IA/MO.
The latest surface map shows an outflow boundary has pushed
through northern Iowa with cooling from the rain. South of this
area, temperature have warmed into the 90s across southern Iowa
with dewpoints in the 60s and 70s. Surface low pressure was
located north of Aberdeen with another local minimum near central
Iowa. Winds are shifting to the southwest over southeast Nebraska
with dewpoints in the 50s and 60s out west.
Severe thunderstorm potential this afternoon and evening-
shower/storm chances continue overnight into Sunday:
Through Sunday night, the closed 500mb low will track toward western
Minnesota and then into Wisconsin Sunday. Multiple rounds of
showers and thunderstorms are forecast as the closed low makes its
way across the region. Severe storms are possible through this
evening.
The 18Z SBCAPE axis of 2000-3500 J/kg axis was located over
western IA into southern Iowa south and west of the outflow
boundary. Through 00Z...this instability axis if forecast to expand
east through central Iowa into southern Minnesota with recovery
heating and the warm front lifting northeast. 0-6km bulk shear of 40
to 55kt over parts of central IA is forecast to continue.
Precipitable water values ranged from 1 to 1.6" across Iowa with
steep mid and low level lapse rates in place. 0-1 SRH of 100-250
m2/s2.
The shortwave trough energy rotating around the closed low this
afternoon will tap into the increase in moisture transport and
instability with showers and thunderstorms becoming more numerous
through the afternoon. The short term models are a little slow
with the afternoon convection as storms have increased over the
last hour over central Iowa. The latest HRRR/RAP continue to show
these storms becoming more widespread across Iowa and southeast
Minnesota...crossing the Mississippi by 22Z. Thunderstorms
continue to increase through 00Z then begin to shift
eastward...with a decrease in coverage by 04Z as this first batch
of storms exits the area. Additional storms develop around 06Z and
push east overnight. Scattered showers and storms develop again
Sunday diminishing diurnally Sunday night.
A tornado watch has been issued for a large part of central Iowa
where convection is surface based and near the warm front. The DMX
0-1 SRH from the VWP was 218m2/s2. The HRRR/RAP track the more
favorable tornado threat south of the area. There are some hints
at more of a line (QLCS) setting up in DVN`s area for southeast
IA. Large hail and damaging winds appears to be a greater threat
in the ARX forecast area with initial long hodographs and elevated
CAPE, however if the storms manage to become surface-based into
the early evening hours where the hodographs show increasing
helicity or if there are interactions with other storms a tornado
cannot be ruled out. The severe weather threat decreases as we
move from southwest to northeast across the forecast area; out of
the instability axis. Overnight, the instability axis shifts east
of the Mississippi River, however MUCAPE looks limited Sunday
afternoon.
Heavy downpours are likely with the storms and where storms repeat
over the same area. Precipitable water values push 1.5 inches,
which combined with warm cloud depths of 4K+, may result in some
areas getting a solid soaking. HREF (24.12Z) guidance 6-hour
PMM/mean/max values of 1"/0.5"/2" exhibiting the wide spread in
individual high resolution deterministic guidance. Resultant
24-hour localized probability matched mean values push 2-2.5" as
sporadic maxima near 4.0" in spots. With the lack of rainfall
recently, 3hr flash flood guidance is at least 2.5 to 3.5".
Some of the dry soils may exhibit hydrophobic behaviors resulting
in increased runoff in higher precipitation rates. Something to
keep an eye on within the heavier storms especially within more
susceptible areas in hilly terrain along the Mississippi River.
Although, any soil saturation today will help decrease soil
hydrophobia, hopefully limiting extent.
Of note later tonight into Sunday, the non-supercell tornado
parameter does start to increase after 09Z and the NAM from 18Z
onward from 1 to 4. Typically a value of 1 or more should be
watched. This will be something that will need to be assessed with
future forecast updates..
Through the new work week, ensemble (GEFS/EPS 24.12) and cluster
(24.00Z) guidance suggests building mid to upper level heights into
midweek with potential ridge running waves providing disagreeable
precipitation chances. Precipitation chances and agreement increases
towards the end of the work week as an upper level trough digs south
from central Canada meeting a lobe of increased low level theta e
originating from the Gulf of Mexico.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 655 PM CDT Sat Jun 24 2023
Showers and thunderstorms continue to lift northeast this evening.
The storms may hold south of KRST. The lightning has been very
sporadic,so included VCTS at KLSE during the evening. If a cluster
holds together will need to amend. Another round of storms is
forecast to develop overnight, however due to the uncertainty in
the coverage have left as VCTS. MVFR/IFR visibilities and ceilings
possible with the steadier rain/storms. MVFR ceilings also try to
expand per the RAP and other model relative humidity forecasts
tonight into Monday. Showers re-develop Sunday thus included more
showers. Winds will remain variable near showers and storms with
some gusts 15 to 25kts. South to southwest winds becoming
northwest and increase 15 to 25kts Sunday.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Zapotocny/JAR
AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Buffalo NY
1037 PM EDT Sat Jun 24 2023
.SYNOPSIS...
A slow moving low will bring occasional showers and a few scattered
thunderstorms to the region this afternoon, with locally heavy
downpours in some locations. This low will weaken over central
Pennsylvania Sunday, although it will still produce a few
scattered showers and isolated thunderstorms across the region.
Another slow moving low will arrive Monday and remain nearby
through the middle of next week, bringing several days of
occasional showers and scattered thunderstorms areawide.
&&
.NEAR TERM /THROUGH SUNDAY/...
A broad/weak mid-level low will drift toward central PA by
Sunday morning. Diurnal shower activity has largely waned at
this point, and any substantial uptick in shower coverage is not
anticipated overnight. While a few slow-moving showers may
manage to develop, this will be exceedingly isolated across the
area overnight.
Fog will also be a concern. Expect radiational cooling as clouds
break up a bit overnight, light winds, and ample boundary layer
moisture supporting areas of fog across much of the region
later tonight through early Sunday morning. Feel the HRRR has a
fairly good handle on this, with a bit more fog likely in the
Buffalo metro area due to the flow off Lake Erie tonight.
The weakening upper level low will shift across the mid-
Atlantic Sunday. MUCAPE values of a 1000 J/KG will be more than
sufficient instability for some thunderstorms to blossom.
Greatest activity will be towards eastern zones and closer to
the upper level low. There will remain the risk for locally
heavy rainfall, but areal coverage will be considerably less
than today since weak ridging aloft will limit storm
development. It will also be a bit warmer than today with highs
in the upper 70s to lower 80s.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
Unsettled weather through this period as a ribbon of +1SD PWATS
remains across the region. Slow moving thunderstorms Monday and
again Tuesday could yield drenching downpours.
Monday and Tuesday a closed upper level low from the northern Plains
will slowly spiral towards the eastern Great Lakes. Additional
moisture from this low into an already moist airmass will bring
surface dewpoints towards the mid 60s, and in some locations
reaching a humid 70F. A LLJ early Monday ahead of a cold front
passage will bring clusters of showers and thunderstorms to far WNY,
with the activity spreading eastward and increasing in coverage area
as daytime instability increases. This LLJ may also bring a few
stronger storms, with localized strong wind gusts, to our region.
Warm cloud depth of 12K and more, tall, skinny CAPE along with
training storms will bring a risk of drenching downpours and
localized ponding of water. The PWATS of 1.5 to 1.75 inches will
fuel the heavy rain from storms. Storms on Tuesday will be slower in
movement than Monday across WNY with the loss of the LLJ, and
weakening of winds aloft as the upper level low passes overhead.
However towards the Finger Lakes and east of Lake Ontario there will
still be a decent flow in the lower levels to maintain movement to
storms, though the added convergence will only add to upward lift and
intensity of the rainfall.
Tuesday will be several degrees cooler than Monday as the upper
level low and its cool pool aloft pushes overhead. Both days will be
humid.
Axis of the sharp trough aloft will move over the eastern Great
Lakes Tuesday night behind a passing cold front. Despite the loss of
diurnal heating after sundown, this will maintain fairly widespread
shower activity overnight, though intensity as well as thunder
chances should notably drop off. A bit cooler and not as humid with
lows in the low 60s to upper 50s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
By Wednesday the upper level trough axis will be pushing across New
York State, with the surface low/main cold front sliding across
central and eastern New York. Latest guidance has trended a bit
slower with the progression of the overall pattern, and if this
trend holds we could be dealing with yet another day of widespread
unsettled weather Wednesday. By this point though, the greatest
moisture and forcing will be east of the forecast area, so not
expecting quite as much active weather compared to Monday/Tuesday.
Greatest potential for additional showers and thunderstorms will lie
from the Genesee Valley eastward, though will need to see how trends
hold moving forward. It will be much cooler and less humid with
temperatures dipping down into the low 70s and even 60s for daytime
highs Wednesday.
The upper trough will continue to weaken as it trudges east of the
Great Lakes in the second half of the week. Still could see some
lingering wrap around or diurnal showers Thursday, though expecting
significantly drier and more seasonable weather overall as surface
high pressure builds back across the central Great Lakes and Ohio
Valley. Friday may be the one dry day this week as a narrow ridge of
high pressure passes across the region.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Shower activity will continue to wane into the evening as TS
chances become lower. Fog will eventually develop at all sites
overnight with ample low level moisture and very weak boundary
layer flow. Given the high sun angle, this will likely mix out
early on Sunday with VFR conditions returning at all sites.
Outlook...
Sunday night through Wednesday...Areas of MVFR or lower with
occasional showers and a chance of a few thunderstorms.
Thursday...VFR to MVFR with a chance of showers.
&&
.MARINE...
Winds and waves will remain relatively low (generally less than 12
knots) through the rest of the weekend and early next week as a weak
pressure gradient remains in place over the eastern Great Lakes.
Patchy fog through tonight will result in poor visibility below
a half mile at some locations.
A few isolated thunderstorms are possible this afternoon and
evening, and again Monday through the middle of next week. Any of
these storms may produce locally higher winds and waves.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Apffel/Hitchcock
NEAR TERM...Apffel/Fries
SHORT TERM...PP
LONG TERM...JJR
AVIATION...Apffel/Fries
MARINE...Apffel/Hitchcock
Area Forecast Discussion
National Weather Service Dodge City KS
647 PM CDT Sat Jun 24 2023
...Updated Aviation Section...
.SHORT TERM...(This evening through Sunday night)
Issued at 1235 PM CDT Sat Jun 24 2023
Midday water vapor satellite imagery and RAP upper air analysis
indicates the synoptic pattern consists of a ~596dm ridge over the
southern plains/northern Mexico, a strong shortwave trough
centered over the northern plains, and a longwave trough axis
extending roughly along the Appalachian Mountain range. Short
range guidance agrees the upper level ridge will expand northward
through the short term period, aided by DNVA in the wake of the
shortwave trough as it moves east-southeast. This will result in
quiet weather over the central plains, granting a break from
severe weather. At the surface, observations show a weak cold
front associated with a low centered near Aberdeen, SD, passed
through our area over the last few hours, however strong solar
insolation and increasing 850-mb temperatures will support
afternoon highs reaching into the low to mid 90s.
Overnight tonight, a secondary cold front is expected to pass
through southwest KS around the 04-09Z time frame. While this
boundary will not bring any precipitation, a modest amount of cold
air will be advected equatorward into our area via 10-20 mph
northerly winds. This will help knock temperatures down below
normal for Sunday, fostering a pleasant afternoon with highs in
the mid to upper 80s.
.LONG TERM...(Monday through Saturday)
Issued at 320 PM CDT Sat Jun 24 2023
Ensemble guidance is in agreement at the beginning of the long
term period regarding the upper level pattern, with a ~595dm ridge
centered over north-central Mexico between a trough over the
western CONUS/east Pacific and a cut-off low spinning above the
lower peninsula of Michigan. These features will move little
through much of the week, as ensemble means suggest the center of
the ridge will only reach LA by 00Z Saturday, still flanked by a
pair of troughs on each side. During this time frame, expect max
temperatures to rise from the upper 80s/low 90s Monday to the
upper 90s/near 100 by Wednesday as the subsident influence of the
upper level ridge peaks, followed by a slow cool down into the
low to mid 90s by Friday as the ridge pulls away. Brief periods of
showers or thunderstorms are not completely out of the question,
especially Tuesday night/early Wednesday associated with a weak
shortwave disturbance ejecting from the base of the western
trough, however ensemble meteograms show nothing close to a
consistent signal.
Friday night through the end of the period, medium range ensembles
agree the upper level ridge will begin to weaken/retrograde as a
trough over eastern Ontario/western Quebec sends a series of weak
shortwave impulses southeastward through the High Plains. The
resulting height falls over the central plains will bring slightly
cooler temperatures with highs in the mid/upper 80s Saturday,
along with at least some precipitation chances. That said, it is
entirely too early to get into the spatiotemporal details given
the inherent uncertainties surrounding summer-time precipitation
at this forecast range, so trends will need to be monitored.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 644 PM CDT Sat Jun 24 2023
Aviation weather will remain tranquil through this TAF period
tonight into the day Sunday. A cold front will push south
overnight, and this will result in an increase in winds from the
north-northeast. Expect wind speeds 13 to 17 knots sustained for a
6 to 9 hour period during the morning hours. As high pressure
builds south, the pressure gradient will relax and winds will
decrease back down below 12 knots from midday through the
afternoon. Flight category will remain VFR with drier air in
place.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 62 87 60 88 / 0 0 10 0
GCK 60 85 59 87 / 0 0 10 0
EHA 60 83 60 90 / 0 0 0 0
LBL 62 85 62 89 / 0 0 10 0
HYS 61 87 59 91 / 0 0 0 0
P28 67 90 64 90 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Springer
LONG TERM...Springer
AVIATION...Umscheid
Area Forecast Discussion
National Weather Service Indianapolis IN
1001 PM EDT Sat Jun 24 2023
.Forecast Update...
Issued at 1001 PM EDT Sat Jun 24 2023
This evening, some mid and high clouds have developed in some weak
lift well ahead of the main system. Adjusted cloud cover to match.
Tweaked evening temperatures based on latest observations.
Thunderstorms continue to develop across Iowa and western Illinois
this evening, with some separation between the storms in Iowa to the
north and the ones in Illinois to the south.
HRRR has been trending toward two separate thunderstorm complexes,
one to the north and one to the south. Looking at current trends and
850-300mb thickness patterns, it may be onto something. Will have to
keep a close eye on how this develops which may affect late night
PoPs.
If this develops as the HRRR (which hasn`t been as consistent as
would like), PoPs would lower some in the central part of the area,
with higher in the northwestern and southwestern areas. For now
though, with continued uncertainty on the developing storms, have
just slowed down PoPs some and kept a broadbrush likely PoP in the
western forecast area late tonight.
Highest CAPE values will remain west of central Indiana through the
night, but enough will move in late that a few severe wind gusts
will remain possible. Still in the realm of possibility would be a
stronger system with a more organized cold pool, but at the moment
odds do not favor this.
Nudged up PoPs in the 12-15Z time frame across northern portions of
the forecast area as timing for the northern area of storms has
slowed a bit.
&&
.Short Term...(This evening through Sunday)
Issued at 242 PM EDT Sat Jun 24 2023
* Turning active with the potential for severe storms late tonight
through Sunday evening...but there remain questions
* Hot and humid Sunday
The long awaited transition from the cool dry regime that has been
common across the eastern US for the last few weeks courtesy of
persistent upper troughing to a growing potential to a more active
pattern courtesy of northwest flow aloft has commenced. The opening
salvo in this pattern shift is in the process of aligning and will
likely come here in two waves late tonight/early Sunday then Sunday
afternoon and evening aided by a potent upper low riding up and over
the ridge axis from the northern Plains into the Great Lakes by the
end of the weekend.
Bottom line up front...the threat for severe storms across the
forecast area over the next 24-30 hours is the best organized risk
we have seen in several weeks and there is high confidence in the
overall setup discussed above. But the devil is in the details and
more questions have arisen with the model data so far today that
keeps the confidence level as to how the convective pattern evolves
at a lower than desired level. As is often the case with the summer
convective regime...the model suite is struggling mightily in the
specifics including the bulk of the CAMs data. This is evidenced
clearly by how badly the model suite missed the overall convective
coverage and intensity over the Missouri Valley this morning. The
importance of mesoscale analysis is critical now and going forward
into Sunday to help best clarify how these two waves of convection
impact central Indiana and the fact that we may not have a more
complete picture on how later Sunday plays out until the convective
cluster tonight moves through. Beyond that...there are components in
the atmosphere for Sunday afternoon and evening that offer potential
mitigating concerns for a more substantial severe threat locally. We
will address all of this below while also highlighting the favorable
parameters for severe weather on Sunday.
First off...quiet but very warm conditions will persist through the
remainder of the daylight hours as the region remains under the
influence of ridging aloft and a weak surface highs. Anticipate
multiple locations to tap 90 degrees later this afternoon and while
hot...dewpoints largely in the 50s will keep RH values at a
reasonable level into the evening. Quiet conditions will persist
through about 06Z before focus shifts to the convective cluster
likely to be approaching from the northwest.
CONVECTIVE THREAT #1:
The initiation of cells that is expected to grow upscale into the
weakening complex for late tonight is commencing currently over west
central Iowa. This will move east then southeast into this evening
around the edge of the ridge periphery and be approaching the
northern Wabash Valley around or shortly after 06Z. What state the
complex is in when it makes it to the forecast area remains to be
seen...but growing signs that the convection will be largely if not
entirely subsevere with model soundings showing the noted
development of a deeper nocturnal inversion and a moisture profile
through 700mb that lacks complete saturation with remnant dry air
lingering in the lower levels. Weak instability aloft will be
present and W/SW 850mb flow at 25-30kts should maintain convection
in a weakened and perhaps scattered state well into the forecast
area during the predawn hours. The wild card is whether the cluster
can toss down a mature cold pool to the northwest of the area this
evening which may enable it to maintain stronger intensity longer
into the region before fully weakening.
The main impacts expected from the convection overnight is gusty
wind...some lightning and much much needed rainfall...although the
weakening nature of the complex over the region would suggest non-
uniform rainfall amounts and not nearly enough to be considered
beneficial for the current state of ground conditions. Still subtle
differences present within the model suite regarding specific track
of the cluster and coverage by the time it arrives over central
Indiana...but general consensus is impacts from 06-07Z in the
northwest through daybreak or shortly after in the southeast as the
complex weakens further and the stronger 850mb flow present earlier
in the overnight dissipates. Expect most if not all of the forecast
area will be free of rainfall by 12-13Z Sunday.
CONVECTIVE THREAT #2:
As mentioned above...rain will diminish and move out rather quickly
Sunday morning with clearing skies following in short order by mid
morning. Model soundings show the lower levels becoming well mixed
and dry adiabatic rapidly...with W/SW winds becoming gusty by
midday. Potential is there for peak wind gusts near 30mph by the
afternoon with temperatures rising fast as well as drier air aloft
is drawn down to the surface. And within that process exists a
potential caveat for widespread convective redevelopment by the
afternoon across central Indiana that cannot be ignored.
The model suite continues to hint at a pocket of very dry air
particularly notable within the 850-800mb layer that has its origins
within the large area of dry air present across the southwest US.
That pocket of drier air will advect into the region in the wake of
the early morning convection and at least be somewhat present during
the afternoon peak heating period. A few of the short range model
members actually intensify the dry air and subsidence within that
layer over the region and that appears to be partially responsible
for the lack of convective initiation over the forecast area within
the 12Z model suite as convective temps are forced into the mid 90s
in spots. Remain skeptical of just how much the drier air within
that layer will mitigate the convective potential as high levels of
instability will be available along with increasing shear and
forcing aloft downstream of the approaching upper low. But this is a
feature that could essentially limit thunderstorm coverage across
our forecast area.
Another potential mitigating factor emanates from what occurs with
the first cluster tonight...namely does a leftover boundary end up
drifting southeast of the forecast area and setting up more from
western Ohio back into southeast Indiana and northern Kentucky? Have
seen way too many times where an initial convective cluster forces a
secondary one to develop southeast of model progs for that very
reason...the inability for the models to accurately depict where
remnant boundaries set up. Recent guidance might be latching on to
that idea with convection growing upscale along our far eastern and
southeastern border and points further southeast from there.
There is plenty still that supports robust convective development if
either of the mitigating factors above ends up being less than or no
issue. The sounding profiles remain impressive with MLCAPEs in
excess of 3000 j/kg and ample low level shear and storm relative
helicities. An increase in 850mb flow through the afternoon should
infuse the column with a bump in moisture ahead of the cold
front...and mid and upper level flow remain supportive with strong
diffluence in the left exit region especially at 300mb. Surface
dewpoints will creep up to their highest levels of the year so far
with an axis of upper 60s and lower 70s air for any convection to
tap into.
Long story short...if convection can overcome any of the issues
mentioned above or they are less of a factor...storms will grow
upscale and become severe rapidly. The amount of instability within
the hail growth zone supports a large hail (and perhaps a
significant large hail) risk in the early stages of development with
damaging winds becoming increasingly more of a main concern with
very steep lapse rates and DCAPE values hovering around 1500 j/kg.
At this time...feel the most plausible scenario will play out this
way for Sunday afternoon. Storms will initiate mid afternoon right
over the center of the forecast area...perhaps near or just west of
a Kokomo-Indy-Bloomington line...with the best threat for severe
convection across the southeast half of the forecast area through
early evening. Still a number of items to hash out and we may not
have a fully clear picture on how Sunday afternoon and evening goes
until the weakening convective complex swings into the area late
tonight.
The main takeaway is to remain prepared and diligent for the risk of
severe weather...especially Sunday afternoon into the early evening.
And maybe more importantly...the next 24-30 hours should bring the
best chance for rain that much of the forecast area has seen in 10-
14 days. As mentioned above...amounts will likely not be anywhere
near sufficient to put a dent in the ongoing drought conditions but
every little bit will help with hints of additional chances for rain
over the next 2 weeks.
Temps...lows tonight will fall into the mid and upper 60s. Had to
tamp down guidance just a bit with respect to highs Sunday...but
with good boundary layer mixing...gusty winds pulling drier air down
from aloft and the possibility of a compressional heating component
ahead of the approaching front...low to even mid 90s are possible in
parts of the area. The addition of much higher dewpoints than we
have seen of late will make Sunday the first truly uncomfortable and
oppressive day of the summer so far with peak heat indices in the
mid and upper 90s possible ahead of any convective development.
&&
.Long Term...(Sunday night through Saturday)
Issued at 242 PM EDT Sat Jun 24 2023
Sunday`s thunderstorm activity should be in the process of exiting
the region at the start of the long range. See the short term
discussion for details regarding those storms and associated
convective hazards.
The system responsible for the aforementioned storms will occlude
over the Great Lakes, and begin its slow exit to the northeast. Most
guidance has enough wrap-around moisture working its way back into
Indiana for scattered showers and possibly thunderstorms on Monday.
Surface instability appears to be limited, but with a weak vort max
rotating around the parent low...enough forcing should be present
for these showers and storms. Will carry chance to likely PoPs,
especially across our northeast, on Monday. Rainfall amounts are
expected to be light.
As the low pulls away, high pressure and associated dry conditions
will return. Relatively quiet weather should persist Tuesday and
into Wednesday, along with cooler conditions within a weak cold air
advection regime behind the low. Warm air advection is then modeled
to return late Wednesday, associated with amplifying ridging across
Texas. This ridge, along with the warm air advection, will allow a
baroclinic zone to set up to our west. Flow aloft will be
northwesterly as the jet stream rides up and over the ridge, which
may lead to favorable conditions for a few MCSs later this week.
Models hint at a small wave cresting the ridge on Wednesday,
triggering upstream convection. Should this consolidate and work its
way southeastward, it may clip our southwestern counties Thursday
morning. Currently, the majority of guidance depicts a theta-e
gradient to our southwest which parallel northwesterly flow aloft.
The most likely path for any developing MCS would be along this
instability gradient. One mitigating factor is the lack of a strong
low level jet. Enough flow may exist to allow for MCS maintenance,
but it may very well be in a weakening phase as it enters Indiana.
This all depends on where upstream convection fires up, which is
difficult to determine at this point in the long term. Will carry
chance PoPs beginning Thursday through the end of the period, as the
upper wave slowly traverses the region amid a lingering instability
gradient.
Given the warm advection beginning late Wednesday, high temperatures
will begin an upward trend thereafter. After a few days with highs
in the upper 70s to low 80s, readings near 90 could once again
return to the region. Lows will likewise increase as low-level
humidity rises and cloud cover limit radiative cooling potential.
&&
.Aviation...(00Z TAF Issuance)
Issued at 643 PM EDT Sat Jun 24 2023
Impacts:
* Convection chances highest for western sites predawn Sunday.
Scattered convection mainly eastern sites Sunday afternoon.
* Variable winds this evening. Southwest winds gusting over 25kt
Sunday afternoon.
Discussion:
Quiet conditions will continue this evening, but there will be some
variable winds with winds varying between SE and SW. A thunderstorm
complex will move southeast into mainly the western sites after 06Z.
Confidence in timing and location is still not as high as would be
desired due to potential mesoscale effects. Will continue with a
VCTS mention west and VCSH east. Bulk of what remains of the complex
will be gone by 12-13Z.
Additional convection will develop Sunday afternoon after 18Z. Focus
looks to be on the eastern sites but will have to monitor closely.
Winds will increase with gusts over 25kt expected.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...50
Short Term...Ryan
Long Term...Eckhoff
Aviation...50
Area Forecast Discussion
National Weather Service Louisville KY
931 PM EDT Sat Jun 24 2023
.Forecast Update...
Issued at 931 PM EDT Sat Jun 24 2023
An occluding cyclone over the Dakotas will slide southeastward into
the upper Midwest by tomorrow morning. As this occurs, a convective
complex currently ongoing over the upper Mississippi River Valley
will slowly work southeastward toward our CWA. This complex should
be somewhat weak or weakening as it approaches our CWA given modest
instability and marginal deep layer shear. However, there may be
just enough of a cold pool established to produce some gusty winds
(likely sub-severe) in spots. Expecting showers and a few storms to
arrive in our western CWA around 6 or 7 AM EDT, working steadily
toward TN, and possibly eastern KY by midday.
The eventual evolution of this complex may play a role in afternoon
destabilization, however there does appear to be quite a bit of time
for the airmass to recover, especially with a pretty healthy
southerly flow in the afternoon, and what should be a good amount of
sunshine. Forecast soundings show a cap that will hold for some time
before convective initiation gets going just upstream with the
arrival of the cold front, and some notable upper level forcing from
the exit region of a mid level jet. By the time evening storms fire,
we should be strongly unstable across the area, with increasingly
favorable deep layer shear overspreading the region. Enhanced Risk
still looks good with all severe modes in play for tomorrow evening.
Expected evolution at this time is for some initial discrete cells
(supercells likely), then gradually congealing into a cluster that
would transition more to a damaging wind threat. Initially, with any
discrete cells, large hail (possibly very large), and a few
tornadoes are possible.
&&
.Short Term...(This evening through Sunday Night)
Issued at 345 PM EDT Sat Jun 24 2023
...Severe Storms Possible Sunday...
Key Messages:
* Multiple waves of showers and storms are expected Sunday, with
wave #1 in the morning and wave #2 towards late afternoon to
into the evening.
* Best chance for severe will be with wave #2 during the late
afternoon and evening
* All severe hazards will be possible with the second wave. Damaging
winds being the greatest, most widespread threat, but large hail
and tornadoes are also possible.
Confidence:
General confidence in a mostly sub-severe morning wave of storms and
a second wave of potentially severe storms in the late afternoon and
evening remains high. Lower confidence remains in the fine details
with regards to timing and location of initial development of
activity with the afternoon/evening wave.
Discussion:
Quiet, warm and muggy conditions will be around for most of the
evening and overnight forecast. Attention will be on the upstream
convection over IA/MO later tonight and through central IL in the
early morning hours. Hi-res CAMs seem to be struggling on a solution
for this activity towards the pre-dawn hours over the region. While
the HRRR brings a elevated clusters of showers and storms mainly
west of the I-65 corridor and south of I-64 between 09-13z the 12z
NAM indicates the cold pool undercutting the activity and
diminishing it before it reaches southern IN/central KY. Model
soundings show a good low level inversion during the early mornings
minimizing the severe threat. With that sad, while the threat of
severe remains low, sub severe gusts of 30 to maybe 40 mph can`t be
ruled out. Lows will be in the upper 60s to low 70s.
Morning wave along with associated cloud cover should clear from the
NW to the SE during the late morning into the early afternoon. The
timing of this first wave will have impacts on how much we can
destabilize over the region during the afternoon and early evening
tomorrow. Models have remained consistent on getting this first wave
out and allowing for temperatures to warm into the upper 80s/low 90s
and dew points in the low 70s. Steep low level lapse rates with
MUCAPE over 3000 J/kg and DCAPE values 1000-1500 J/kg help support
the idea of a strong widespread severe wind threat. Model soundings
still indicate a weak capping inversion around 850mb during the
afternoon into the early evening. This could delay the onset of
development until the evening depending on how strong the cap is in
the afternoon.
Strong 500mb jet noses into the Ohio Valley during the afternoon
south of the upper low that works into the Great Lakes during the
evening. This will help to provide deep layer shear in a west-
northwest flow making large hail a possibility. SPC HREF Ensemble
shows STP values as high as 3 to 4 and good amount of 0-1/03km SRH
support the possibility of a few tornadoes. Depending on the
strength of the cap, current thinking is our best chance for severe
activity will be around 6pm to 1am EDT over the region. This fits
very well with the updated SPC Day 2 convective outlook placing
central KY in an Enhanced Risk with southern IN in a slight risk.
.Long Term...(Monday through Saturday) Issued at 250 PM EDT Sat
Jun 24 2023
To start the extended period, the stacked low initially centered
over Michigan will slowly wobble towards the eastern Great Lakes
region through Tuesday and then gradually lift across the Northeast
CONUS through the end of the week. In its wake, central CONUS
ridging will gradually expand and build across the region through
the end of the period.
Monday - Tuesday...
Chances for showers and storms (20-40% PoPs) to start the week in
association with subtle disturbances rotating around the upper low.
Will see low-end PoPs generally along and northeast of a HNB-GLW
line, although best chances will be across southeast IN into east-
central KY closer to the low pressure. Additionally, expect winds to
be a bit breezy Monday and Tuesday with sustained speeds of 10 to
15+ mph and gusts to 30 mph possible. Temperatures will be
relatively cooler in the wake of the cold front, with highs in the
upper 70s to mid 80s for most.
Wednesday & Beyond...
Uncertainty increases by midweek but in general expect mostly dry
weather for Wednesday as surface high pressure drifts overhead. Low
end chances for showers and storms will return for Thursday and into
the end of the period as several disturbances rotate through the
periphery of the ridge and dive southeast across the mid MS Valley
and OH/TN Valleys. Temperatures will warm through the end of the
week, with highs potentially reaching the lower to mid 90s by Friday.
&&
.Aviation...(00Z TAF Issuance)
Issued at 754 EDT Sat Jun 24 2023
Things are VFR at the TAF sites, and will remain that way for the
remainder of the evening and much of the overnight. Around dawn, a
complex of weakening showers & maybe some storms is expected to
mainly impact HNB/BWG. SDF is a little more uncertain, but can`t
rule it out. Have the best timing in a Prob30 groups for those 3 TAF
sites, but will not include LEX being farther east. Biggest impacts
would be gusty winds and some brief vis reductions in heavier rain.
Past midday, expect morning convection to be gone and gusty SSW
winds to take hold of the area, otherwise VFR conditions will
prevail with Sct Cu around 5K feet. By evening, showers and
thunderstorms, possibly strong to severe, are expected to develop
and move ESE ahead of a cold front and strong upper level support.
Large hail, damaging wind, and a few tornadoes are all possible
along with your typical heavy rain and lightning threats. Since
storms are expected to arrive at LEX after 00z, will be including
mention in next TAF cycle for them.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...BJS
Short Term...BTN
Long Term...JML
Aviation...BJS
Area Forecast Discussion
National Weather Service Marquette MI
741 PM EDT Sat Jun 24 2023
.UPDATE...
Issued at 741 PM EDT SAT JUN 24 2023
Rain that impacted the central UP earlier this evening is moving out
over Superior at this time. Fog has developed in its wake, locally
dense throughout portions of Marquette county. This may justify some
quick headline if we don`t mix out soon. For the rest of tonight,
most of the UP should be dry. The exception will be the far west,
with ongoing hit and miss activity so far. Guidance continues to
indicate that some of the convection currently over far western WI
will make it into the western UP late tonight as well. Otherwise,
clouds will continue to fill in overnight. Temperatures this evening
have been complicated by cold pooling from earlier rain showers, but
generally hover in the mid 60s to upper 70s. We still look to bottom
out in the upper 50s to lower 60s by early Sunday.
&&
.SHORT TERM...(Through tonight)
Issued at 224 PM EDT SAT JUN 24 2023
Upper air pattern consists of a closed 500 mb low near the Black
Hills region in a trough over the northern plains. This trough and
closed low head east into the upper Great Lakes region tonight.
Convection is starting to fire now on lake breeze boundaries and
becoming spotty and have this in the forecast. Had to expand some
pops to the east as lake breeze convection has taken off as well.
Central and western cwa will continue to see the best chance for
pops into tonight and have scattered pops mostly in those areas.
Overall, did not make too many changes to the going forecast.
.LONG TERM...(Sunday night through Saturday)
Issued at 406 PM EDT SAT JUN 24 2023
By 12Z Sunday, a 999 mb low supported by a completely vertically
stacked upper level shortwave will be along the MN/WI border per the
12Z GEFS ensemble mean. This stacked low will slowly meander ESE to
Lake Huron by 00Z Monday and southern Ontario by 18Z Tuesday,
maintaining strength as is progresses. This will provide the lift
for an extended period of rain showers across the UP through at
least Tuesday morning. The GEFS mean remains consistent in providing
the UP with 1-2 inches of rain while the EPS has been inconsistent
run to run between the UP only receiving around a half inch of rain
(such as the 18Z run yesterday) and getting an inch and a half of
rain or more (such as the 00Z run last night), with the 06Z run
indicating a similar solution to the GEFS. With PWAT values expected
to be around 1.25-1.5 inches (approaching the 90th percentile of
NAEFS climatology), there will be potential for some localized heavy
downpours, but NBM 6 hour QPF 50th percentile rarely exceeds 0.25
inches, meaning that the weather of the early week will be
characterized by long-duration light rain.
As more high resolution model data comes in, consensus shows that
there will be some dry slot that forms, but there`s disagreement on
where the dry slot occurs. Still, the potential exists for some
areas to get much less QPF than the rest of the UP. The RAP does
show on Sunday afternoon a band of around 1000 J/kg of SBCAPE along
Lake Superior between Baraga and Grand Marais, so there is some
thunder potential, but with very little speed shear at 350mb and
below, convection will struggle to maintain organization. Still,
with sufficient instability, forcing, and moisture, the somewhat
veering wind profile may provide just enough organization for an
isolated severe wind gust or hail storm, but widespread severe
weather is not expected.
Cyclonic flow around the low will wrap the smoke plumes from fires
in Quebec and northeast Ontario towards the UP, with the 12Z HRRR
Smoke run bringing a high concentration plume of near-surface smoke
over the UP Sunday evening, reducing visibility to locally 7 miles
or less. Areas of rainfall may help precipitate some of the smoke
particles out of the local atmosphere, so the effects of smoke may
not be as widespread as model output suggests. However, in rain-free
areas, fine particulate concentrations will be similar to or
worse than today, and today`s conditions prompted the first
official (second unofficial) Air Quality Alert in WFO MQT history.
After precipitation ends from west to east Tuesday, high pressure
builds over northern Ontario and the Hudson Bay as ridging builds
aloft, leading to a quiet weather day Wednesday. While the NAEFS
does show humidity values in the bottom 2.5-10 percent of
climatology, elected not to lower dew points/RH due to uncertainty
in the effect of rainfall occurring the multiple days prior on the
following surface RH.
Confidence is increasing in a shortwave approaching Thursday and
bringing more light rain to the UP, potentially taking the form of
a weak clipper or influencing the development of a weak Colorado
Low. With multiple subtle features to track, ensemble spread
increases vastly into Friday and beyond. 500mb height anomaly from
the GEFS shows a general ridging pattern over the central CONUS
with troughing over the eastern CONUS into the weekend, which
would lead to northwesterly flow aloft and cooler temperatures,
but potentially more shortwaves to produce precipitation as well.
Should a more active pattern result, this would bring welcome
moisture to areas of the UP which have been vulnerable to fire
weather concerns as of late.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 741 PM EDT SAT JUN 24 2023
Hit and miss shower activity continues throughout the forecast
period with associated restrictions. In the wake of early evening
showers, mainly dry conditions are expected at SAW and CMX tonight
while lingering fog and mist lead to MVFR visiblity. This may lift
at SAW over the next couple of hours, but should hold at CMX the
rest of the night. IWD, meanwhile, stands the best chance at seeing
additional rounds of rain overnight. VFR conditions at IWD should
deteriorate to MVFR later tonight and hold through the rest of the
forecast period. Otherwise, a period of low level wind shear will be
possible at IWD and CMX later tonight.
Heading into Sunday, rain becomes more likely at all terminals
beginning during the mid morning before becoming more hit and miss
into the afternoon. Visiblity will have improved to VFR with more
persistent south/southeast winds, but ceilings will lower to MVFR by
the afternoon hours. Further drops to IFR are possible at IWD by the
early evening. Thunder cannot be ruled out during the afternoon, but
the timing and location is too uncertain to include in the TAF.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 406 PM EDT SAT JUN 24 2023
As a low pressure system passes south of Lake Superior,
northeasterly gusts up to 30 knots are occurring over the far
western portions of the lake. Tonight, gusts fall to around 20 knots
until reintensifying to near 30 knots Sunday. Also on Sunday,
easterly wind gusts increase to 20 to 25 knots over the north-
central regions of Lake Superior. Sunday night and Monday morning,
winds begin to become more northerly, with wind gusts of around 25
knots for the west half of the lake. By Monday evening, winds will
be northerly with gusts of up to 30 knots in the central portions of
Lake Superior. Tuesday morning, winds remain northerly but gusts
over the east half will be around 25 knots. As the low departs to
the east and high pressure builds in, winds fall below 20 knots late
Tuesday night. The highest waves this forecast period will be
Tuesday morning, with significant wave heights up to 7 feet from the
north over the east half of the lake. While no severe weather is
expected, there are chances for thunderstorms through Tuesday
afternoon across much of Lake Superior. Additionally, smoke plumes
from wildfires in Canada will create conditions that are potentially
hazardous to certain individuals with respiratory vulnerabilities in
rain free areas this weekend.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
UPDATE...LC
SHORT TERM...07
LONG TERM...GS
AVIATION...LC
MARINE...GS
Area Forecast Discussion
National Weather Service Morristown TN
919 PM EDT Sat Jun 24 2023
...New UPDATE...
.UPDATE...
Issued at 917 PM EDT Sat Jun 24 2023
The early evening showers have dissipated on schedule, and the
forecast for tonight generally looks to be on track. Will just
make some minor tweaks mainly to hourly temps and dew points with
this update.
&&
.SHORT TERM...
(This evening through Sunday)
Issued at 327 PM EDT Sat Jun 24 2023
Key Messages:
1. Scattered to isolated showers this afternoon will dissipate by
evening, with low clouds and fog in some areas overnight.
2. An upstream MCS will enter the area around midday Sunday, mainly
affecting southern sections through the early to mid afternoon.
Potential for a few strong to marginal severe storms possible.
Discussion:
Northern sections remain under a mid/upper level shortwave trough
that is gradually progressing east. Scattered showers in that area
will dissipate with the loss of heating and the continue departure
of the trough/vort max. There are some signals in the NAM, HREF, and
LAMP guidance that low clouds and fog will develop tonight in
portions of the northern TN Valley and SW VA. Will mention some
patchy fog in the Wx grids and broken cloud cover in the Sky grids
early Sunday morning.
The main concern for this period will be the impacts of an upstream
MCS currently ongoing in Iowa that is expected to approach the area
on Sunday. The CAMS are not in good agreement on the track of the
MCS, or its intensity when it reaches our area. The FV3 and NAMNest
take what remains of this MCS across Middle TN and northern AL,
missing most of our area except perhaps the southern Plateau area.
The HRRR and ARW track it farther north, but with much diminished
intensity. Based on the HREF CAPE probs, we will not have much
instability to support a severe threat in our area - the high
instability stays to our west. But these MCS pattern are notoriously
tricky, and confidence remains low. A few strong storms will be
possible, and an isolated marginally severe storm will be possible,
with the main threat being strong wind gusts. The forecast will
have chance PoPs for the entire area on Sunday, highest in the
southern sections and peaking around 18Z.
&&
.LONG TERM...
(Sunday night through next Saturday)
Issued at 327 PM EDT Sat Jun 24 2023
Key Messages:
1. The chance for showers and storms will increase again Sunday
night. There is still uncertainty regarding the exact timing but a
few strong to severe storms are possible. Greatest threat will be
damaging wind and hail, however, a brief spin-up cannot be totally
ruled out, mainly along the Cumberland Plateau.
2. A return to a more typical diurnal summertime pattern is expected
mid-week, where the chance for an afternoon shower/storm will favor
higher elevations.
Discussion:
The general synoptic pattern Sunday night will consist of a
vertically stacked system in the Great Lakes Region. A moderate to
strong H5 jet with 50-60kt WNW flow will position atop the region.
H85 flow will increase to between 30-40kts in response to the upper
level divergence. A surface boundary draped across the Ohio Valley
into the Mid-Mississippi River Valley will be a focus point for
convection as we head into Sunday night and overnight.
Recent model solutions have trended a little bit quicker with the
convection as previous runs generally had activity entering the
Plateau area around 10-12Z Monday. While there still remains
uncertainty in the finer details such as coverage and exact timing,
the general trend for HREF ensemble members is for the line to
approach Sunday night and diminish/exit the region into the early
morning hours Monday. This is an important thing to note as the
exact timing will play a role in the chances to see strong/severe
weather. The later the activity occurs the more stable the
atmosphere will become, especially at the surface, and chances for
strong to severe storms will be relatively lower. HRRR and GFS
generally depict around 800-1500 MLCAPE with mid-level lapse rates
low to high 7 C/km. NAM soundings are a bit more bullish with MLCAPE
approaching 2000J/kg along the Plateau with quite similar lapse
rates. Given the above, the primary threats for any stronger to
severe storm will be damaging wind and hail. With the presence of a
weak LLJ after about 0Z, there will be upwards of 30kts of effective
shear and near 20kts of 0-1km shear so cannot totally rule out a
brief spin-up, mainly along the northern Cumberland Plateau.
Isolated to scattered showers and storms may re-develop on a diurnal
summertime pattern Monday afternoon, with a focus in the higher
elevations and northeastern areas. Steep mid-level lapse rates will
remain in place and depending on the timing of aforementioned
convection, there could be some instability that re-develops Monday
afternoon as well. Cannot rule out a stronger/severe storm during
that time frame for previously mentioned locations as well but
confidence is low at this time. Otherwise, ridging will build into
the Ohio Valley and begin to impact the region bringing reduced
chances for daily shower/storm chances in the afternoon among the
presence of a subsidence inversion. A warming trend also looks
likely with the potential for above normal temperatures by late week
into the weekend. A shortwave disturbance could bring increasing
chances of rain by the end of the extended as well.
&&
.AVIATION...
(00Z TAFS)
Issued at 642 PM EDT Sat Jun 24 2023
Any lingering shower around TRI will end quickly, but convection
probability increases again during the day Sunday with the best
chance at CHA and TYS. Will include VCTS both sites Sunday
afternoon. Other concern is possible fog development overnight,
and the best chance looks to be at TRI so will continue to include
MVFR vsby later there tonight with a few hours of tempo IFR
conditions around sunrise.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 67 89 72 91 / 0 50 50 30
Knoxville McGhee Tyson Airport, TN 65 88 69 86 / 0 50 50 30
Oak Ridge, TN 64 89 67 86 / 10 40 50 30
Tri Cities Airport, TN 61 86 66 83 / 20 40 50 40
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...
AVIATION...
Area Forecast Discussion
National Weather Service Nashville TN
846 PM CDT Sat Jun 24 2023
...New UPDATE...
.UPDATE...
Issued at 840 PM CDT Sat Jun 24 2023
The few showers that popped up over Middle Tennessee earlier have
all but dissipated, and so we are left with several hours of
benign weather before the next round of convection. A convective
complex has been brewing over eastern Iowa this evening, and the
HRRR keeps this system together and brings it into Middle
Tennessee Sunday morning on a NNW-SSE trajectory. Right now, it
looks as if the current grids are projecting the morning
convection a little earlier than what the HRRR is showing, but
we`ll hold off making any changes for now.
&&
.SHORT TERM...
(This afternoon through Sunday Night)
Issued at 143 PM CDT Sat Jun 24 2023
Temperatures across the area have climbed into the 80s to 90
degrees with partly cloudy skies. The radar is clean with surface
high pressure influences centered to our south. The main focus of
the forecast continues to be on Sunday with the potential of
severe weather. We will see two shortwaves slide by the area on
Sunday. The first will be overnight tonight and into Sunday
morning. Models show showers and storms moving into the area
prior to dawn in the west and weaken as they move toward the
plateau by mid morning. Severe storms are not expected with this
wave.
By the afternoon, skies will be mainly clear with dew points
climbing into the low to mid 70s. Lapse rates will rapidly
increase to between 7 to 8 degrees C above 700 mb by the evening.
Temperatures will be fairly warm between 925-800 mb which will
cap off widespread storm development in our area during the
afternoon hours. Our eyes will be back to the W/NW ahead of the
second shortwave. If storms develop in West TN/West KY, expect
them to move into our area as an MCS. Damaging winds will be the
main threat, but large hail will also be a threat given the
impressive lapse rates. The low level helicity will be on the low
side, so tornadoes will not be a big threat. Confidence in the
timing, location, and the coverage of storms is low at this point,
but we are confident the ingredients will be in place. As far as
general timing, storms could move into the west/northwest as early
as 5 pm and move through the area and be clear by 1 or 2am.
One other note for Sunday afternoon will be the heat index
values. With temperatures in the low to even mid 90s along the
Tennessee River, afternoon temperatures will feel like 100-105.
&&
.LONG TERM...
(Monday through next Saturday)
Issued at 143 PM CDT Sat Jun 24 2023
Behind Sunday`s activity, quieter conditions will return for Monday
through Wednesday with seasonable temperatures. The large upper
ridge centered over Texas will expand and shift eastward on
Thursday. Temperatures will climb into the low to mid 90s on
Thursday and we could see temperatures in the west approach 100
degrees by Friday.
&&
.AVIATION...
(00Z TAFS)
Issued at 612 PM CDT Sat Jun 24 2023
VFR conditions expected this evening into the start of the
overnight with light winds. A line of showers and thunderstorms
will enter the NW part of the area after 10z. This line will
gradual weaken as it pushes south and east and will be mainly
showers by the time it reaches eastern areas after 15z. MVFR/IFR
will be possible with this line mainly for our western terminals.
This line will clear the area by the afternoon. Additional
thunderstorms are expected tomorrow evening into the early
overnight and some of the storms could be strong to severe.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 71 93 72 91 / 40 70 60 10
Clarksville 71 95 70 90 / 60 70 60 0
Crossville 63 84 65 83 / 10 40 60 30
Columbia 69 92 71 90 / 40 70 40 10
Cookeville 66 86 67 85 / 10 50 60 20
Jamestown 64 85 65 83 / 10 40 70 20
Lawrenceburg 68 90 70 90 / 30 60 40 10
Murfreesboro 69 91 70 90 / 30 60 50 10
Waverly 69 93 69 88 / 60 60 60 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Rose
SHORT TERM...Reagan
LONG TERM....Reagan
AVIATION.....Mueller
Area Forecast Discussion
National Weather Service Tallahassee FL
950 PM EDT Sat Jun 24 2023
...New UPDATE, HYDROLOGY...
.UPDATE...
Issued at 942 PM EDT Sat Jun 24 2023
The forecast is on track, so no updates are planned this evening.
&&
.NEAR TERM...
(Through Sunday)
Issued at 313 PM EDT Sat Jun 24 2023
West-southwest flow aloft prevailed across the region today, whilst
southwesterly sfc winds off the Gulf continued to entrain a moist
airmass across the southeast FL Big Bend /PWATS aoa 1.7 inches/.
This moist airmass, coupled with daytime destabilization has
resulted in isolated showers and thunderstorms that initiated in
the Gulf and moved across portions of the southeast FL Big Bend
earlier this morning. Since then, the activity has more or less
been confined to portions of the southeast FL Big Bend, whilst the
activity in the Gulf decays. This activity is not expected to
become severe, but lightning and brief gusty winds are still a
possibility.
Precip is expected to wane shortly after sunset. Concurrently,
flow aloft will veer to the north-northwest courtesy of a
departing UA trough across the northeast CONUS and an intruding UA
ridge to our west. Model solutions hint at the potential for an
MCS to dive along the flow aloft to potentially across southern AL
and the western FL Panhandle tomorrow late aftn/early evening.
The HRRR is a bit more bullish with the MCS by showing it
impacting a bit more of the CWA. If this is the case, would not be
surprised if SPC adds a Marginal Risk to portions of the CWA for
tomorrow /latest outlook has a Marginal Risk bumped up to our
western CWA attm/. If this trend holds, gusty winds, small to
moderate sized hail and moderate to heavy rainfall will be the
main threats.
Overnight lows will be in the 70s, with daytime highs in the 90s
on Sunday.
&&
.SHORT TERM...
(Sunday night through Monday night)
Issued at 313 PM EDT Sat Jun 24 2023
An upper ridge will continue slowly progressing
east over the Southern Plains with an upper low traversing through
the Northern Plains to the Great Lakes / Ohio Valley Region by
Monday evening. Model spread regarding the magnitude, timing, and
placement of upper level flow (20-30kts) leads to some uncertainty
regarding what may occur tomorrow evening.
Tomorrow evening, the main discrepancy between models appears to be
how far south the upper level support makes it with some guidance
showing 30-40kts of 500mb flow making it into the western FL
Panhandle whereas others show it weakening near central AL. As
previously discussed, an MCS appears likely given the NW flow regime
and effective shear around 20-30kts hinting at some organization.
Thus, opted to keep pops around 20-30% mainly in our SE AL counties.
On Monday, better upper level support via NW`erly flow will enter
the region in the afternoon hours resulting in better kinematics on
top of favorable instability areawide. Once again, the flow regime
hints that another MCS event appears likely with higher confidence
regarding timing and placement. The highest PoP`s (40-60%) have been
mostly confined within our SE AL and SW GA counties, decreasing to
around 20-40% in our FL counties as forcing is expected to weaken
and leave the area as it continues south. The main threats both days
will be wind and perhaps some small hail, especially on Monday where
thermodynamic profiles appear much more buoyant.
Temperatures will reach the low to mid 90s with overnight lows
generally hovering around the mid 70s.
&&
.LONG TERM...
(Tuesday through Friday)
Issued at 313 PM EDT Sat Jun 24 2023
The aforementioned upper ridge will continue slowly
trekking east to the Gulf Coast bringing one more chance at an MCS
Tuesday evening. For the remainder of the long term, afternoon
seabreeze convection will prevail once again ushering in a more
traditional summer pattern. With the high meandering over the area,
temperatures will likely reach into the upper 90s areawide and
possibly breaking into the 100s within our FL counties Wednesday
through Friday. Additionally, overnight lows will remain in the mid
70s.
&&
.AVIATION...
(00Z TAFS)
Issued at 719 PM EDT Sat Jun 24 2023
A calm night is expected for this evening`s TAFs. There is a
minor chance for light showers affecting the ABY terminal
overnight, but confidence for that is low, so not shown in the
TAFs. Tomorrow, a possible MCS may develop and approach the DHN
terminal later in the afternoon and extending past the end of this
TAF period.
&&
.MARINE...
Issued at 313 PM EDT Sat Jun 24 2023
Winds through the period will blow of the WSW with
predominately gentle breezes expected, though a moderate breeze will
be possible Monday and Tuesday evening before slightly decreasing on
Wednesday. Seas will remain around 2 feet through the weekend before
briefly dropping to 1 foot on Monday. Seas are expected to increase
again to 2 feet on Tuesday as some storms may reach our waters in
the late evening. Winds near and within these storms may lead to
locally intense gusts and erratic winds.
&&
.FIRE WEATHER...
Issued at 313 PM EDT Sat Jun 24 2023
Main area of isolated precipitation today was noted off the Gulf and across
portions of the southeast FL Big Bend. Computer models hint at the return of
precipitation /possibly severe/ to impact portions of southeast AL and western
FL Panhandle on Sunday. High mixing heights with moderate dispersions will persist
throughout the remainder of the weekend, particularly for the GA
districts.
&&
.HYDROLOGY...
Issued at 950 PM EDT Sat Jun 24 2023
Rivers continue to run high after heavy rains over the past week.
Waters are routing downstream, and a generally dry Saturday was
helpful.
The Steinhatchee River at Cross City crested this evening in minor
flood, so it will start to slowly fall. It will take a few days
for the Steinhatchee to fall below flood stage.
The Aucilla at Lamont will be in the process of a flat crest over
the next 24 hours in minor flood.
Many other rivers are running high but within their banks,
including the Ochlockonee, Ichawaynochaway, Withlacoochee,
Fenholloway, Econfina, Apalachicola, and Choctawhatchee.
Flash flooding is unlikely for the next 7 days.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 71 94 74 92 / 0 10 0 40
Panama City 74 89 76 88 / 0 10 10 30
Dothan 69 93 72 91 / 0 20 10 50
Albany 69 93 72 89 / 0 10 10 50
Valdosta 69 93 72 92 / 0 10 0 40
Cross City 70 93 72 91 / 10 10 0 10
Apalachicola 74 88 76 87 / 0 10 0 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 5 AM EDT /4 AM CDT/ Sunday for
FLZ108-112-114.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Bowser
SHORT TERM...Worster
LONG TERM....Worster
AVIATION...Montgomery
MARINE...Worster
FIRE WEATHER...Bowser
HYDROLOGY...Haner