Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/26/23
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1022 PM EDT Sun Jun 25 2023
.SYNOPSIS...
Warm and humid today with scattered showers and thunderstorms
this afternoon before diminishing this evening. Another muggy
night follows with a stronger disturbance and a surface boundary
resulting in more showers and thunderstorms tomorrow. A few
stronger thunderstorms are possible capable of heavy downpours.
The upper level low will persist through much of the work week
leading to continued chances for showers and storms.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 10:15 PM...Last of expected convection is moving northward
across the southern Adirondacks at this time. Adjusted PoPs to
reflect current conditions. Expecting a lull in activity for a
period overnight. Otherwise, minor adjustments to the other
parameters.
PREVIOUS DISCUSSION [8 PM]...Convection continues to fire up
and move northward across the area this evening. The strongest
storm today occurred over the Capital District as a storm
interacted with intersecting outflow boundaries. It has
weakened. Storms have been producing locally heavy rainfall and
we have been issuing Special Weather Statements addressing that
threat. The HRRR did pick up on scattered convection moving
northward across the region in the vicinity of a surface
boundary along with a short wave trough passing to our
southwest. Have scattered showers and isolated thunderstorms
with heavy rainfall in the forecast for the rest of this
evening. Updated other parameters to better reflect current
conditions and trends.
Very warm day with Albany hitting 89 degrees, Glens Falls 86,
Poughkeepsie 87 with 85 degrees at Pittsfield, North Adams and
Bennington.
PREVIOUS DISCUSSION [2 PM EDT]...Partly to mostly sunny skies
continue this afternoon with hot and humid conditions thanks to
insolation and quite the warm air mass aloft (850hPa isotherms
+14C to +15C). Dew points remain high in the upper 60s making it
very muggy. GOES16 water vapor imagery shows our shortwave
continuing its slow approach through NJ tracking northeastward.
The forcing for ascent has been well to our south in NJ and PA
with just a few isolated showers developing off the terrain as
we met the convective temperature. With very light flow through
the column, showers are slow moving and with not much forcing,
showers have not grown tall enough to produce any thunder.
As the shortwave progresses northward through the afternoon and
early evening, additional forcing should lead to a few more shower
and eventual isolated storm development so maintained isolated
to scattered shower/storm in the forecast. This matches with
high res CAM guidance as well but overall activity will be
limited.
Mid level lapse rates are weak and the 0-6 km shear is
extremely poor at 10 KT or less. However, some modest mean
SBCAPEs of 1000-1500 J/kg on the latest HREF supports isolated
strong thunderstorms (though not expecting severe) with bursts
of heavy downpours due to the anomalous PWATs in excess of
1.50". Not expecting any widespread hydro problems, though the
threat for an isolated flash flood can not be ruled out due to
the slow movement of any convective cell. WPC continues with the
daily "Marginal Risk" for excessive rainfall for most, if not
all the forecast area.
Showers and storms diminish with the lose of daytime heating
with most CAM guidance suggesting isolated to widely scattered
showers (possibly isolated storms) weaken by 03 - 06 UTC. Then,
mid and upper level clouds clear out leading to another opportunity
for radiational cooling to lead to low stratus and possibly
patchy fog. Since daytime rain amounts will be much less than
yesterday, fog should not be as widespread. Otherwise, yet
another muggy night is expected with temperatures falling into
the mid to upper 60s.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
We start off the day generally quiet yet muggy with any
lingering fog or low stratus lifting shortly after sunrise.
Upstream, a potent closed low will be approaching from the Ohio
Valley and Great Lakes but will be slow moving. The best height
falls and forcing for ascent from this disturbance look to hold
off until Monday afternoon and Monday evening when the upper
level cool pool and drier air move overhead. Thus, we have
maintained likely POPs for showers and thunderstorms from 18 UTC
Monday to 06 UTC Tues. In addition to upper level forcing, a
sfc boundary will also be tracking eastward along the leading
edge of the best height falls. Initial convection should develop
once we reach the convective temperature but will likely be
isolated to scattered in nature. However, as the sfc boundary
arrives during the afternoon and drier/cooler air impinges
aloft, shower/storm activity should turn more numerous with
potential for a more organized line of rain and storms to
develop. Exactly when this line forms and where it tracks is
still uncertain as there are still discrepancies in the latest
CAM guidance. But, with 0-6km shear intensifying to 25 - 30 kts
and MUCAPE values still 1000 - 1500 J/kg, storms that become
better organized could become bowing segments potentially
producing strong winds. PWATs are still high ranging 1.50 -
1.75" so it will remain humid. Maintained gusty wind and heavy
downpour wording for Monday P.M and evening from the previous
forecast. This also matches the latest SPC outlook which has
most of our region in a marginal risk with a slight risk just to
our south.
Otherwise, Monday will be humid and warm once again with
temperatures warming into the upper 70s to mid-80s. Southerly
winds also turn a bit breezy as the pressure gradient ahead of
the incoming upper level low tightens.
Shower and storm activity likely continues into Monday evening
as the stronger height falls and sfc boundary arrive. Despite
the lose of daytime heating, shower and thunderstorm activity
looks to linger even during the overnight hours due to the
upper level forcing giving us a rather wet night. Temperatures
do not move much only falling into the upper 60s with muggy
condition continuing.
The forecast unfortunately does not improve heading into
Tuesday as we still will be under the influence of the slow
moving upper level low. Rounds of rain and embedded
thunderstorms remain possible through the day as the cool pool
from the closed low tracks overhead, PWATs remain elevated near
1.50" and height falls continue downwind of the incoming parent
low which will still be centered to our west. CSTAR warm season
research has documented the tilt of closed/cut-off lows and
their associated sensible weather. It is challenging to pin
point the best windows of opportunity for rain and storms so
trended likely POPs Tues morning to categorical for Tuesday
afternoon. Given rain/embedded storms and cloud coverage,
temperatures should be cooler in comparison to recent days with
daytime highs likely struggling to reach 80. But, it will remain
muggy and humid thanks to continued southerly flow ahead of the
closed low.
Depending on how where and how frequently rain and heavy
downpours occur, isolated flooding is possible, especially for
areas that may already be saturated from the back-to-back days
of showers and storms. This is why WPC maintains its marginal
risk for excessive rainfall for Tuesday.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A continuation of an unsettled pattern ensues for the extended
forecast period. By Wednesday morning, the upper-level, closed low
pressure system and associated negatively tilted trough looks to be
situated over the greater portion of the East Coast, its axis
plunging through the forecast area. Though by 12z Wednesday morning
the once highly potent disturbance will have begun to weaken,
southerly flow continually advecting ample moisture off the Atlantic
into the pre-existent, moisture rich environment will support yet
another day of potentially widespread showers Wednesday. With
requisite lift along the low`s occluded boundary, PWAT values
continuing to be upwards of +2 STDEVs above normal, and modest
instability (CAPE values on the order of 500-1200 J/kg), it remains
a fair probability that diurnally driven, locally heavier showers
and thunderstorms could develop, leading to some downpours that will
likely contribute to ponding of water in poor drainage areas.
Thunderstorms are not expected to be severe as winds and shear look
to remain on the lower side.
The aforementioned trough will continue to weaken as it progresses
along an easterly track and fills Wednesday into Thursday,
decreasing the widespread nature of showers and thunderstorms.
Unsettled weather still remains a high likelihood, however,
especially Thursday afternoon where once again diurnal influence
will aid in supporting showers and thunderstorms. At this time,
model depiction gives the impression of less widespread
precipitation for Thursday, placing a higher concentration of
showers in the extreme Eastern New York and Western New England
where the better forcing exists as the low continues to push further
in that direction. Models then have some inconsistencies as it
pertains to the position of the low as Thursday becomes Friday,
leading to some uncertainties surrounding conditions. The ECMWF is
currently more wet than the GFS and Canadian as it tracks the low
just inside the New England Coast by 12z Friday, leading to a
progression into the Gulf of Maine by 18z and forcing showers back
into the region (especially in Western New England) as cyclonic flow
continues to dominate. The GFS runs the closest solution in
comparison, keeping the low along a slightly more northerly track,
but also sending showers into the eastern-most portions of the
forecast area Friday. Conversely, the CMC-NH takes the low on a fast-
track up the New England Coast, having it completely exit the region
before 12z Friday and therefore leaving dry conditions in its wake.
Because of this uncertainty, kept PoPs at high chance for Friday.
Further into the weekend, the forecast becomes even more uncertain
in terms of defining periods of dry weather ahead of the next system
looking to bring what could be another soaking rain into the region.
Saturday has the potential to be the driest day of the period
depending on the timing and track of the next incoming system, but
model discrepancy makes it difficult to say for sure at this time.
Will continue to monitor trends as lead time decreases throughout
the week.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
THROUGH 00Z TUESDAY...Current radar shows scattered showers and
thunderstorms throughout the forecast area. So far limited impacts
to terminals have arisen, though KPSF previously entered LIFR
conditions briefly and KALB is set to experience a passing
thunderstorm within the hour. Monitoring radar trends closely,
though additional convection is not likely in the next couple of
hours. It is possible that a shower or thunderstorm could reach KGFL
as the current line oriented west to east from Schoharie County
through Berkshire County continues to move north. Will make
amendments where necessary.
Once showers and thunderstorms cease this evening, VFR conditions
should prevail at all terminals for much of the night. Guidance is a
little varied as it pertains to cloud cover. An incoming cutoff low
pressure system poses the biggest threat for overspreading clouds
tonight, but latest model runs show the potential for a slower track
that would allow SCT to FEW clouds to linger and limit ceiling
formation. As a result, pushed back the development of ceilings to
between 08-12z. Ceilings tomorrow will ride the fine line between
VFR and MVFR as clouds filter in and showers and thunderstorms as a
result of the low move in. IFR to LIFR conditions certainly cannot
be ruled out as a result of locally heavier showers and
thunderstorms tomorrow afternoon, but kept MVFR for now.
Winds throughout the 00z TAF period will be southeasterly, ranging
in magnitude from 6-11 kt.
Outlook...
Monday Night: High Operational Impact. Likely SHRA...TSRA.
Tuesday: High Operational Impact. Definite SHRA...TSRA.
Tuesday Night: High Operational Impact. Likely SHRA...TSRA.
Wednesday: High Operational Impact. Definite SHRA...TSRA.
Wednesday Night: High Operational Impact. Likely SHRA...TSRA.
Thursday: High Operational Impact. Likely SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday: Moderate Operational Impact. Chance of SHRA...TSRA.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...IAA/Wasula
NEAR TERM...IAA/Wasula
SHORT TERM...Wasula
LONG TERM...Gant
AVIATION...Gant
Area Forecast Discussion
National Weather Service Amarillo TX
644 PM CDT Sun Jun 25 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Monday night)
Issued at 223 PM CDT Sun Jun 25 2023
Temperatures will begin to slowly climb starting tomorrow across
the Southern Plains. Highs are not expected to be in the triple
digits, but upper 80s to mid 90s are likely tomorrow afternoon.
Chances are small, but there could be a few thunderstorms tomorrow
afternoon across the western TX Panhandle.
Based on the 25/17z H500 RAP analysis, high pressure is centered
along the US/Mexico border across far southwestern Texas. The main
axis of this ridge is just to the west of the forecast area at
this time with westerly flow aloft. Temperatures have been
increasing into the mid 70s in the north to mid 80s in the south
as of the time of this writing. Temperatures will be a bit cooler
today as a cold front moved across the area earlier this morning.
Upper level high pressure will slowly move off to the east tonight
into tomorrow. Southerly low level winds will bring the return of
hot temperatures on Monday. Highs should generally be in the upper
80s across the north and mid 90s across the south. Surface dew
points are forecast to remain in the upper 50s to mid 60s across
the Panhandles tomorrow. Models continue to show a weak shortwave
moving across eastern NM to west TX late tomorrow afternoon into
the evening hours. Ample moisture looks to remain across the area
in the low to mid levels tomorrow and the lift provided by the
wave should generate a few isolated thunderstorms. These isolated
storms likely will not be high rainfall producers, but some light
precip is possible. Given this scenario, have introduced a broad
area of low end mentionable PoPs across the central and west
tomorrow evening. In addition to the light rainfall, some gusty
winds may be possible with these storms as they may produce some
downburst winds with DCAPE values around 1400-1700 J/kg.
Muscha
&&
.LONG TERM ...
(Tuesday through next Saturday)
Issued at 223 PM CDT Sun Jun 25 2023
Hot temperatures will be the main headline through the middle of
this week. Widespread high temperatures in the upper 90s to over
100 are expected on Tuesday and Wednesday. These days should
mainly be dry, but a few storms are possible on Tuesday. Thursday
and beyond, daily chances for thunderstorms will be possible and
temperatures should decrease each day going into next weekend.
Upper level high pressure will be located over central Texas at
the beginning of the long term forecast. This will lead to a
ridging pattern over the south central CONUS on Tuesday and
Wednesday. Southerly to southwesterly low level winds will advect
a warmer airmass over the Southern High Plains on Tuesday. H850
temperatures by peak heating on Tuesday could be in the mid 30s C,
which would lead to temperatures at the surface in the upper 90s
to just over 100. Confidence in triple digit temperatures, mainly
across the southern TX Panhandle, is increasing given the NBM 25th
percentile high temperatures for Tuesday are now at 100 or above.
The latest 25/12z deterministic guidance is in fairly good
agreement with keeping the top of the ridge over the northern
sections of the CWA or just to the north on Tuesday
afternoon/evening. This allows a shortwave trough to move across
this area late on Tuesday. Moisture will continue to be in place
over the Panhandles and a few high based storms may move across
the northern zones. Have kept PoPs minimal at this time, but will
continue to monitor for the thunderstorm potential on Tuesday
evening.
Given warm overnight lows on Tuesday night into Wednesday morning,
high temperatures should be a bit warmer on Wednesday with
continued strong WAA over the Panhandles. The NBM/LREF
probabilities for temperatures of 100 or above is much higher on
Wednesday for a majority of the Panhandles, with widespread areas
of 70 percent or higher chances of hitting 100 degrees. High
pressure shifts off to the east on Thursday through the remainder
of the extended. WAA will not be as strong on Thursday through
next weekend and temperatures are forecast to slowly decrease each
day. With the ridge moving off to the east, this will allow
shortwave troughs to move across portions of the Southern Plains
during these days. Mid level moisture should be on the increase
and the PVA associated with these waves should be enough to
generate some storms each day starting Thursday. The mesoscale
details will certainly change, but some strong to severe storms
may be possible during this time frame.
Muscha
&&
.AVIATION...
(00Z TAFS)
Issued at 637 PM CDT Sun Jun 25 2023
For the 00Z TAFs, isolated thunderstorms may develop very late
Monday afternoon across western and central parts of the Texas
Panhandle. However, the expected sparse coverage and very low
probability of a storm impacting a specific TAF site precludes
mentioning in the forecast at this time. Otherwise, VFR conditions
are expected to prevail at KGUY, KDHT, and KAMA through late
Monday afternoon.
02
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 66 93 70 103 / 0 10 20 0
Beaver OK 62 88 67 95 / 10 0 10 10
Boise City OK 60 90 64 96 / 0 10 10 10
Borger TX 66 95 71 105 / 10 10 20 0
Boys Ranch TX 66 97 69 104 / 0 10 20 10
Canyon TX 65 95 69 104 / 0 10 20 0
Clarendon TX 67 92 70 104 / 0 10 10 0
Dalhart TX 62 92 66 99 / 0 10 20 10
Guymon OK 62 89 67 98 / 10 10 10 10
Hereford TX 66 97 68 104 / 0 10 20 0
Lipscomb TX 63 88 67 98 / 10 0 10 10
Pampa TX 66 91 70 101 / 10 10 10 0
Shamrock TX 67 91 70 102 / 0 0 10 0
Wellington TX 69 94 71 105 / 0 0 10 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&
$$
SHORT TERM...05
LONG TERM....05
AVIATION...02
Area Forecast Discussion
National Weather Service Binghamton NY
947 PM EDT Sun Jun 25 2023
.SYNOPSIS...
Lingering showers and thunderstorms will generally diminish this
evening, but given the pattern we are stuck in, there`s a slight
chance for a pop-up shower or thunderstorm just about anywhere
overnight, with the Finger Lakes Region somewhat favored.
Thunderstorm chances will increase on Monday, with an uptick in
coverage and intensity, as another low pressure system pushes in
from the west. More afternoon showers and storms are expected
yet again Tuesday and Wednesday.
&&
.NEAR TERM /THROUGH MONDAY/...
945 PM Update...
Showers and thunderstorms north of the Thruway will continue to
shift north of the region over the next hour or two. Additional
pop-up showers and storms over Steuben County may make it into
the central Finger Lakes over the next 2-3 hours, but will
likely diminish after that. Further south and west, a line of
thunderstorms moving across Western PA is likely to weaken as it
looks to graze the far western portions of the CWA.
00Z HRRR has backed off the threat for early morning convection,
but coarser-scale models still show a vort max rolling rolling
through the area during that time frame, so kept the morning
PoPs going for the time being.
300 PM update...
Upper level low pressure is currently centered over southern PA
and it will continue to drift E-NE this evening. The best
instability and forcing this afternoon and evening will be
across the Poconos and southern Catskills. PWATs remain high and
driving flow is very weak, so slow moving thunderstorms will
have potential to produce localized heavy rainfall. Also, short
Corfidi vectors below 10 knots support back building/training
cells. The overall flash flood threat in the region is low,
however, localized/isolated flash flooding is possible,
especially if storms set up over areas that have already seen
heavy rainfall the last couple of days.
Tonight, convection should subside around sunset with the loss
of heating. Another upper level low will start approaching from
the west overnight and tomorrow. CAMs are indicating that the current
ongoing MCS heading into Michigan and Ohio this afternoon, will
weaken overnight, but still holds together enough to bring some
showers and thunderstorms back into our region tomorrow morning.
Severe thunderstorm potential will likely be determined on how
fast this morning convection clears.
If the morning showers and storms push through and there is
some clearing ahead of the approaching short wave, then greater
potential exists for severe storms across NE PA and into
southeastern NY. Strong warm air advection on deep SW return
flow should further destabilize things tomorrow afternoon with
dew points getting into the upper 60s to low 70s. Forecast
soundings are showing CAPE values around 1500 J/kg across
northeast PA and parts of southern NY, as well as 0-6 km bulk
shear of 30 to 35 knots by late Monday afternoon. Further north
the environment is not as favorable, and although showers and
thunderstorms are still possible, severe thunderstorms are not
expected due to lower shear and instability.
There is also the potential for heavy rain with any of these
storms tomorrow. Deep moisture and even a slight risk of some
training convection over areas that are already saturated could
prove sufficient for significant runoff in some areas. There are
parts of northeast PA within a Slight Risk of Excessive
Rainfall according to the updated Day 2 Outlook from WPC with
the bulk of the region still in a Marginal risk.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
On Tuesday model consensus is that an upper level low over the
eastern Great Lakes will very slowly move east and open up into
a trough across western NY into Western PA. This puts central NY
and northeast PA into a continued moist deep southerly flow.
With low- level moisture in place and cooling aloft from the
upper wave to our west, diurnal induced instability once again
will lead to showers and thunderstorms boiling up in the
afternoon. Models do indicate some lingering shower activity in
the morning with an expansion in activity in the afternoon so
will have lower POPs in the morning and higher in afternoon.
Models do show modest instability again Tuesday with minimal
vertical wind shear. Best chance for isolated severe storms will
be across the Catskills/Poconos in central NY/northeast PA
Tuesday where the higher instability is projected to be along
with bulk wind shear 0-6 km around 25 to 30 knots. Since the
vertical wind shear is rather weak all of central NY/northeast
PA is in a marginal risk for flash flooding. Tuesday night with
loss of diurnal heating shower and thunderstorm activity will
wane at night hence we will lower POPs.
For Wednesday, more of the same, as upper level trough axis very
slowly moves into NY and PA with diurnal driven instability. This
will lead to more diurnally driven showers and thunderstorms. So we
will have a diurnal increase in POPs Wednesday afternoon/evening and
lower POPs Wednesday night with loss of heating.
Started with NBM POPs but lowered POPs in the morning since they
look way too high given the impression of an all day rain.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Persistent slow-moving upper level trough/low will be over
eastern NY to eastern PA/NJ. Again with low-level moisture in
place and cooler air aloft more diurnally driven showers and
thunderstorms will form, peaking afternoon/early evening and
then tapering off Thursday night. Again, Started with NBM POPs
but lowered POPs in the morning since they look way too high
given the impression of an all day rain.
For Friday, upper level low trough finally moves east of NY and PA
as next upper level wave moves into the upper plains. Models are
showing some diurnally driven QPF indicating lingering shower and
thunderstorm activity. Certainly coverage will be lower than
previous days and focused more in our eastern forecast area from
Catskills to Oneida Co in NY. Friday night looks like the best
chance for a dry night before the effects of the next upper level
low arrive Saturday will a chance for additional showers and
thunderstorms. This next system will affect NY and PA Sunday with
continued chance for more showers and thunderstorms.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Thunderstorms will diminish in coverage early this evening,
though another round of brief IFR and thunder is possible at SYR
for another hour or two. Patchy fog is likely to develop
overnight, especially in sheltered valleys which received rain,
where IFR conditions are possible overnight. There is a chance
for additional showers and thunderstorms to roll through in the
early morning hours Monday, followed by a stronger round of
storms Monday evening.
Outlook...
Monday Night through Friday...Repetitive pattern, with
occasional restrictions possible in scattered showers and
thunderstorms and fog possible overnight.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MPK/MPH
NEAR TERM...MPK/MPH
SHORT TERM...DJN
LONG TERM...DJN
AVIATION...MPK/MPH
Area Forecast Discussion
National Weather Service Birmingham AL
920 PM CDT Sun Jun 25 2023
...New MESOSCALE UPDATE, AVIATION...
.MESOSCALE UPDATE FOR SEVERE THUNDERSTORMS...
Issued at 854 PM CDT SUN JUN 25 2023
To start off, the Heat Advisory will expire at 9 pm. Due to the
lack of early day storms, heat indices jumped into the 105-109
degree range from Montgomery to Tuscaloosa to Hamilton and areas
westward. Temperatures tomorrow will not be quite as warm and the
advisory will be allowed to expire.
Well, the complex thunderstorm scenario is playing itself out.
After a slower start to the day, thunderstorms have built
southward down the eastern half of Central Alabama. These storms
have produced damaging winds and large hail a good cold pool
developed and a large gradient exists with most thermodynamic
parameters. These storms will continue southward and most likely
will exit the area just after midnight.
The next short wave trough and associated thunderstorms were just
entering far northwest areas. These storms have also been severe
west of here, producing mostly damaging winds. The latest RAP
analysis has a pool of instability roughly west of I-65. SB/ML
CAPE values at least 3000 and Bulk Shear increasing the next few
hours west to 40kts or so. Therefore, these storms will certainly
have the potential of producing damaging winds and large hail for
several hours. These storms will mostly likely also build
southward at some point following the available instability.
The watch that is place handles both of these areas of potential
severe storms. Therefore, some areas may be removed before 3 am as
the instability is used up.
75
&&
.SHORT TERM...
(Today through Monday)
Issued at 1215 PM CDT SUN JUN 25 2023
We continue to watch and wait for storms to blossom across Central
Alabama as we go into the afternoon hours. We already have our
first isolated convection developing across the northwest counties
within parameter space that continues to grow more volatile with
each hour that goes by. Due to the delay in the initial onset of
storms, we`re going to realize our high temperatures of the day in
the lower 90s, especially along and west of the I-65 corridor and
across our far southern counties. RAP analysis is now indicating
SBCAPE values of 5000-6000 J/kg across Mississippi as surface
dewpoints have still not mixed in these areas. Unfortunately,
we`ll have to issue a Heat Advisory as a result with Heat Index
values running between 103 and 106 across the western two tiers of
counties. A PWAT/MLCAPE gradient is currently bisecting Central
Alabama from north to south, ranging from 1.8 to 1.9 inches in the
west to 1.3 inches in the far east. We expect deeper moisture and
PWATS to continue to rise from west to east through the
afternoon, providing more fuel for severe storm development.
Based on initial development ongoing now and high-res guidance
trends this afternoon, we could be looking at isolated supercell
development first with large hail and damaging wind potential. As
widespread storms develop later on this afternoon, an MCS is then
expected to move southward or southwestward across Central
Alabama during the late afternoon and early evening hours.
Widespread damaging wind potential would accompany any MCS that
happens to develop as the cold pool rapidly advances with slab-
like lifting. Convective trends will continue to be monitored
through the afternoon, so stay tuned for future updates. PoPs were
adjusted back a few hours to account for the later initiation and
high temps were adjusted upward areawide.
56
&&
.LONG TERM...
(Monday night through next Saturday)
Issued at 259 PM CDT SUN JUN 25 2023
No major changes were made to the start of the extended. Keeping
pops ahead of the sagging surface boundary that may be through
part of the NRN part of the area by Mon evening. A large surface
ridge is expected to build over E Conus for mid week. In the
upper levels, an upper ridge currently over NRN Old Mex will
spread EWD as the week progresses. By Thu, it should be stretched
from TX to AL. With double ridging, the heat will build over C AL.
Guidance is trending warmer for Thu/Fri.
While it is still too early to issue an excessive heat watch (for
anticipated excessive heat warnings at the earliest 72 hours), I
can up the confidence to 4 out of 5 for heat in the HWO for then
and Fri. We have no mentioned pops for Thu and only isolated for
Fri with this setup. By Friday, the surface front S of C AL should
move back NWD as a warm front, so isolated pops are possible. At
the very least, heat advisories will be needed for most of the area
but possibly even an excessive heat warning for the WRN counties.
Triple digits (actual temps/ not heat indices) are possible for
the WRN half of C AL. This would warrant the advisory even without
the humidity factor. On Sat, the heat will still be a factor, but
values are not expected to be quite as scorching as Thu/Fri.
Cloud cover should increase and rain chances return, but still
toasty.
08
Previous long-term discussion:
(Tuesday through Saturday)
Issued at 350 AM CDT SUN JUN 25 2023
An active weather pattern is expected to continue through much of
the week.
An amplified ridge persists across much of the Central CONUS with a
generally stationary trough along the East Coast. This synoptic
setup places Central AL under a northwesterly flow regime. Models
pick up on a few shortwave impulses sliding through the region, each
one supporting thunderstorm development. Given the MCS mode, any one
of these could lead to strong to severe storms (mainly wind).
However, model guidance really struggles with resolving the timing
and evolution of each wave, so confidence isn`t there to include
severe storms in the forecast for any specific day at this time.
The low level ridge builds eastward over the Gulf States Thursday
into Friday, leading to a warming trend for the region. High
temperatures on both days will be in the upper 90s with many
locations nearing or hitting 100 degrees. Heat index values will be
in the 105-110+ degree range. However, the temperature forecast is
highly dependent on the timing and location of any convective
systems that may move through Central AL those days. The hot/humid
air mass continues into Saturday, so we may be looking at a
prolonged period of potentially dangerous heat with little overnight
recovery (lows in the upper 70s) , which could exacerbate the risk,
especially for vulnerable populations.
25/Owen
&&
.AVIATION...
(00Z TAFS)
Issued at 854 PM CDT SUN JUN 25 2023
Made a few changes since the initial issuance earlier this
evening. For the most part, held the ceilings and vis VFR. There
will be an area of showers and thunderstorms moving southward and
these may affect MGM/TOI before 06z. Added a tempo for thunder as
this area glances the southern terminals. Another area of storms
has entered northwest Alabama. These storms will move into the
west and north terminals after 03-04z. Some wind gusts and hail
are possible with any of the storms along with temporary reduced
vis/ceilings. Will monitor closely for the potential of fog
development. Extremely moist low levels may allow for some fog
development especially if it rains then clears. Think there will
be plenty of mid and high clouds around, so this is to be
determined. Winds will be mainly west southwest 5-10kts.
75
&&
.FIRE WEATHER...
Showers and storms are possible now into Monday with lower
chances on Tuesday as the associated front moves closer to the
immediate Gulf Coast. Minimum relative humidity values will
remain well above critical thresholds. 20 foot winds should
average from the southwest this afternoon, west-southwest on
Monday, and west-northwest on Tuesday with speeds close to 10
knots at times, especially on Tuesday based on the current
forecast.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 69 91 66 91 / 30 30 10 0
Anniston 70 90 69 92 / 80 40 10 10
Birmingham 72 92 71 94 / 50 30 10 10
Tuscaloosa 72 93 71 96 / 70 30 20 10
Calera 71 91 71 93 / 50 40 20 10
Auburn 71 87 71 91 / 90 50 20 20
Montgomery 73 92 74 94 / 60 50 20 20
Troy 72 92 73 95 / 60 50 30 30
&&
.BMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...75
LONG TERM....08
AVIATION...75
Area Forecast Discussion
National Weather Service Boston/Norton MA
1003 PM EDT Sun Jun 25 2023
.SYNOPSIS...
Low pressure to our west will continue the moist, muggy, and
unsettled pattern through the upcoming week. There will be daily
shots for scattered showers and thunderstorms.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
955 PM Update:
Following observed trends and RAP/HRRR/AWC visby guidance, have
issued a Dense Fog Advisory for the South Coast of RI and MA,
Cape Cod and the Islands until 10 AM Monday. I`ve also issued a
MWS to address marine dense fog conditions for boaters/vessels.
Couple things to monitor for tonight. One is the extent of fog
and stratus coverage. While many sites along the South Coast,
Cape and Islands are in pea-soup fog given upper 60s dewpoints
over the cooler waters. Foggy conditions have been restricted to
the immediate coastal areas; however as the near-surface temps
cool through radiational effects, we expect at least stratus to
expand northward from the southern coastal waters through the
overnight. The modest southerly winds add reduced confidence to
how far north any locally dense fog may expand. Will continue to
monitor observations and trends for possible northward expansion
of the Dense Fog Advisory to address travel impacts for the
Monday morning commute, or if a fog SPS is warranted. The dense
fog advisory and marine weather statement highlights areas where
there is strong confidence in fog being dense for the most
sustained stretch of time. Opted for a little more leeway on the
end timing as there`s some level of uncertainty on how quickly
fog disperses and it may linger well after sunrise.
Next is for PoPs/Wx for the overnight/early AM period, more so
for southeast New England. While showers and storms from this
afternoon have ended, there is a disturbance aloft/"swirl" seen
in water vapor imagery coming off the NJ coast. SPC`s
mesoanalysis shows about 2000 J/kg of most-unstable CAPE over
the ocean waters too, fueled by the degree of moisture/humidity
around. The 00z NAM and the HRRR try to blossom widely scattered
showers or t-storms over the coastal waters overnight into the
pre-dawn hrs. Will keep an eye on radar and satellite trends to
see if any elevated convection atop the fog layer tries to get
going.
Otherwise, a continued muggy night in store, likely to be a
rolling theme these next few days.
Previous Discussion...
We continue to see scattered showers popping up across SNE this
afternoon, and to our west across NY state. Showers seems to be
forming in the vicinity of a very subtle surface boundary with
S/SW/SE flow at places like Hartford, Worcester, and Boston
while Orange, Nashua, and North Adams have light winds out of
the N/NW. The thinking continues to be that these will be sub
severe thunderstorms, but contain heavy rain. As such, the main
concern is heavy downpours beneath slow moving storms (thanks to
very little steering flow) which could cause urban and poor
drainage flooding. Showers and thunderstorms will diminish after
sunset with loss of diurnal heating but may linger through
midnight in northern MA as they shift into northern New England
given no change in airmass. We`ll have a lull in precip
overnight then renewed rain chances during the very early
morning hours of Monday as the upper low ejects northeastward
over New England. Moist southerly flow continues which will
bring the renewal of fog and low stratus clouds overnight as
well as very mild low temperatures in the mid to upper 60s.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Monday the mid-level low over the Great Lakes shifts east with a few
weak disturbances rotating through and this, together with an
increasing low level jet, will bring the threat of scattered
thunderstorms to the region. Some of these could be strong to
severe. We`ll have plenty of moisture to work with as southerly flow
continues to advect in dewpoints in the upper 60s and low 70s.
Together with high temperatures in the upper 70s and low 80s it will
produce CAPE values on the order of 1000-1500 J/kg. This, in an
environment with rather poor 0-6 km shear values 0f 20-25 kts and
mid level lapse rates <6C/km doesn`t spell widespread severe
weather, but isolated strong to severe storms. The better severe
weather threat lies to our southwest where a potent MCS will be
decaying as it approaches, but may hold together long enough to
bring some damaging winds to western MA/CT. Something to keep an eye
on but a low probability. During the overnight hours the cutoff low
with cyclonic flow aloft moves even closer and shower/thunderstorm
chances continue, as do the muggy conditions.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Highlights
* Unsettled and humid through much of this week. Daily opportunities
for scattered showers and thunderstorms. Heavy downpours possible
at times.
* Strong to severe storms possible Tue and Wed.
* Watching the track of distant Cindy as it could bring higher
swells to our region late this week, and perhaps into next weekend.
* High temperatures generally near to slightly below normal, with
above normal low temperatures.
Hard to not sound like a broken record with the forecast this week,
but it is what it is. Latest guidance suite has not deviated much
from the prevailing pattern. Expecting a mid level cutoff over the
Great Lakes to evolve into more of an open longwave trough over
southern New England toward mid week. This trough then lingers
nearby right into next weekend. There are some signs this trough
could finally move offshore early next weekend, only to have another
mid level trough develop to our west late next weekend. Thus, not
much of an overall respite. Have the greatest confidence in the
details into Thursday, but even that is only about an average
confidence.
Latest projections of surface-based CAPE values throughout this week
have been fairly consistently somewhere in the 500-1,000 J/kg range.
Some days could see slightly higher values, but the confidence in
that is not overly high. Current thinking remains daily chances for
mainly afternoon and evening showers and thunderstorms through this
portion of the forecast. Not thinking widespread severe weather is
likely, but isolated stronger storms are possible, especially
Tuesday into Wednesday. Will need to monitor this potential over the
coming days. Severe weather predictability is too low towards the
end of this upcoming week to mention it now.
Will continue to monitor the track of distant Cindy, as it may
follow the Great Circle line toward our region. This could bring us
higher swells/rip current risk late this week, and perhaps into the
holiday weekend.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight...Medium confidence.
A few stray showers or thunderstorms will linger through 02Z
towards the northern MA border. Otherwise, VFR transitions to
IFR/LIFR in fog/stratus once again. Showers and thunderstorms
approach from the west and southwest, especially toward daybreak
Monday. IFR vsby in heavier showers and thunderstorms.
Monday...High confidence.
Widespread IFR and MVFR in showers and thunderstorms throughout
the region. Locally heavy rainfall possible. S winds 10-15 kt.
Monday night...High confidence.
Scattered showers and thunderstorms through the overnight hours.
IFR conditions return in fog and low stratus. SE winds 10-15 kt.
BOS Terminal...High confidence in TAF.
Conditions lower to MVFR/IFR tonight as stratus moves back in.
BDL Terminal...High confidence in trends, moderate in exact
timing.
Conditions lower to MVFR tonight and perhaps IFR as stratus
moves back in.
Outlook /Tuesday through Friday/...
Tuesday: Mainly MVFR, with local IFR possible. Breezy. SHRA,
chance TSRA.
Tuesday Night: Mainly MVFR, with areas IFR possible. Breezy.
SHRA, chance TSRA.
Wednesday: Mainly MVFR, with local IFR possible. Breezy. SHRA
likely, slight chance TSRA.
Wednesday Night: Mainly VFR, with areas MVFR possible. Breezy.
SHRA likely, isolated TSRA.
Thursday: Mainly VFR, with areas MVFR possible. Breezy. Chance
SHRA, slight chance TSRA.
Thursday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, isolated TSRA.
Friday: Mainly VFR, with local MVFR possible. Chance SHRA,
slight chance TSRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
315 AM update...
Through Monday Night: High confidence.
Light south to southwest winds mainly 10 to 15 kt with a few
gusts to 20 kt. Seas below Small Craft Advisory criteria.
The main concerns for mariners through Monday night are more
from dense marine fog each night. Visibility may be reduced to
below 1 mile at times. On Monday, showers and thunderstorms
become more widespread, with heavy rainfall possible, and this
continues Monday night. Seas 2 to 4 feet.
Outlook /Tuesday through Friday/...
Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft. Rain showers, slight chance of
thunderstorms.
Tuesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Rain showers, slight
chance of thunderstorms.
Wednesday: Moderate risk for Small Craft Advisory winds with
local gusts up to 30 kt. Rough seas up to 8 ft. Rain showers,
slight chance of thunderstorms.
Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Rain showers likely,
isolated thunderstorms.
Thursday through Thursday Night: Winds less than 25 kt. Seas up
to 5 ft. Chance of rain showers.
Friday: Winds less than 25 kt. Seas up to 5 ft. Slight chance
of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Dense Fog Advisory until 10 AM EDT Monday for MAZ020>024.
RI...Dense Fog Advisory until 10 AM EDT Monday for RIZ006>008.
MARINE...None.
&&
$$
SYNOPSIS...Belk/BW
NEAR TERM...Belk/Loconto/BW
SHORT TERM...BW
LONG TERM...Belk
AVIATION...Belk/Loconto/BW
MARINE...Belk/Loconto/BW
Area Forecast Discussion
National Weather Service Columbia SC
1006 PM EDT Sun Jun 25 2023
.SYNOPSIS...
Convection dissipates tonight with another round possible Monday
morning. A cold front is expected to move through the area late
Monday. Scattered showers and thunderstorms are expected along
and ahead of the front with increasing confidence in strong to
potentially severe thunderstorms late Monday afternoon and
evening. Drier air spreads into the area Tuesday into Wednesday
with seasonable temperatures. More typical summertime conditions
follow for the late week period as ridging slowly builds east.
&&
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
Convection will continue to dissipate across the CSRA tonight as
the forecast area becomes more stable. Still expect at least
scattered showers in portions of the CSRA until around midnight
before clearing. A shortwave will move into the area around
daybreak with the latest HRRR indicating that convection that is
currently developing in northern KY moves into the area. While
surface based instability will be lacking, some elevated
instability will likely be present so have introduced pops into
the area with at least a slight chance of an elevated
thunderstorm. Debris cloudiness from convection today remains
overnight with lows generally in the low 70s across the forecast
area.
&&
.SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
Monday and Monday Night: We continue to monitor the potential for
strong to severe thunderstorms late Monday afternoon into Monday
evening. An upper low over the Great Lakes drifts east as the
associated trough digs into the Eastern CONUS. An attendant cold
front will approach from the west and showers and thunderstorms are
expected to develop later in the day along and ahead of the
boundary.
The day will begin with partly to mostly sunny skies with
a slight chance for a passing shower or two, mainly in the CSRA. A
shortwave and pre-frontal trough will move towards the region Monday
afternoon and will serve as the lifting mechanism for convection.
Model soundings support the development of showers and thunderstorms
with CAPE values exceeding 2000 J/kg and modest shear around 30
knots. Thunderstorms are most likely to develop over the Midlands
and this is reflected in the latest SPC Day 2 convective outlook
which places the CSRA in a Marginal (1/5) risk for severe
weather with a Slight (2/5) risk over the Midlands. Damaging
winds and hail are the primary severe hazards though an isolated
tornado cannot be ruled out, especially over the Northern
Midlands. Any thunderstorms that develop have the potential to
produce locally heavy rainfall and flash flooding, especially in
areas that saw flood conditions last week. This potential is
reflected in the Day 2 WPC ERO outlook which places the entire
CWA in a Marginal (1/4) risk for excessive rainfall. The cold
front sweeps through Monday night putting an end to the
thunderstorm threat. It will be a warm, humid and breezy day
with highs in the lower 90s. Temperatures Monday night fall into
the upper 60s to lower 70s.
Tuesday and Tuesday Night: The trough shifts east on Tuesday as
drier begins to filter in behind the departing front. Expect
generally sunny skies on Tuesday with only a slight chance for a
shower or thunderstorm over the far southeastern forecast area
in the afternoon. While it will be drier, temperatures will not
be much lower than on Monday with forecast highs in the upper
80s to lower 90s. Clear and dry conditions Tuesday night with
lows in the upper 60s to near 70 degrees.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The extended opens with continued dry conditions and near normal
temperatures courtesy of northwesterly flow ahead of a building
ridge over the Central United States. Ridging gradually extends
eastward towards the forecast area during the late week period. This
results in rising heights with above normal temperatures expected on
Friday and Saturday. A more typical summertime pattern sets up as
moisture returns during the late week period. Expect diurnally
driven afternoon and evening convection each day starting on
Thursday.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Thunderstorms are moving into the forecast area ahead of a
shortwave trough. Expecting these showers to dissipate prior to
reaching majority of TAF sites, but added a TEMPO tsra at
Augusta terminals. Light and variable winds overnight with low
confidence in fog formation. The main cold front will near the
area Monday evening and gusts will increase to around 25kt in
the afternoon ahead of it. Best timing of convection will be
just beyond the TAF period and chances remain too low in
central South Carolina and Georgia to include in this update.
EXTENDED AVIATION OUTLOOK...Restrictions possible at times in
showers and thunderstorms Monday evening and overnight as a front
moves through the area. Drier air expected starting Tuesday through
mid-week with low confidence in restrictions.
&&
.HYDROLOGY...
Several major rivers in the region remain in flood due to the
widespread heavy rainfall last week and reservoir operations.
Please refer to water.weather.gov/ahps for the latest river
stage observations and forecasts.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
543 PM MDT Sun Jun 25 2023
.SHORT TERM...(This evening through Monday night)
Issued at 315 PM MDT Sun Jun 25 2023
Current surface analysis depicts the deepening low pressure cell
continuing its track eastward into the Great Lakes and dragging its
associated cold front through the Central CONUS, with surface high
pressure slowly moving eastward from the the Four Corners into the
High Plains. Mostly clear and dry weather was observed this morning,
with a dry airmass providing dewpoints in the 40s and 50s across
southeast Wyoming and the Nebraska Panhandle.
Main concerns over the next 24 to 36 hours focus on the return of
severe weather today with a marginal risk for severe weather across
the central High Plains, and again for tomorrow with a marginal risk
for severe weather for the northern High Plains. Latest CAMs have
convection beginning today during the late afternoon/early evening
hours along northern Laramie County and tracking eastward into
Nebraska Panhandle. Dewpoints have continued to climb at KCYS
throughout the late morning, with high 40 to low 50 dewpoints by
9am MDT. HiRes model guidance is keying into some pockets of
higher SBCAPE around 1200+ J/kg, 700-500mb lapse rates at 8.6C/km,
EBWD at 53 knots, and SHIP values pinging some bigger hail into
the mixture. Due to how well the HRRR has been doing over the last
few days, isolated severe thunderstorms capable of producing
strong winds and bigger hail are possible this afternoon across
central to northern Laramie County before continuing on into
Goshen County and ending their journey into the Nebraska
Panhandle. Should be short-lived tonight once the initial cells
begins to deteriorate as the convective parameters dwindle into
the evening.
Into tomorrow, the threat of strong to severe storms continues with
a marginal risk for severe weather for the northern High Plains. Mid
to upper level ridging is expected to slink slightly to the east,
with an upper level trough struggling to shift eastward from the
Pacific Northwest. Embedded disturbances within the flow will have
enough power to dig across central to northern Wyoming to give us
our next chance for precipitation for the northern High Plains.
Thermodynamic profiles continue to support stronger storms with
SBCAPE at 1600 J/kg, 0.9 inch PWATs, 700-500mb Lapse Rates around
8.5C/km, plenty of shear, and SHIP values above 1. A decent amount
of uncertainty for this forecast with the HRRR keeping most of
this precipitation well to the north and mostly out of our CWA.
Due to the consistency of the HRRR, will remain cautiously
optimistic that most of the stronger storms should remain to the
north of the CWA. However, within this atmospheric setup, seeing
good southeasterly flow and all three ingredients of moisture,
instability, and lift, will hint towards a threat for severe
thunderstorms over the northern Panhandle and into Converse and
Niobrara Counties in Wyoming. All in all, looking like a later
show tomorrow with most impacts in the late afternoon and evening
hours.
.LONG TERM...(Tuesday through Sunday)
Issued at 315 PM MDT Sun Jun 25 2023
Not many changes made to the previous forecast package with models
continuing to show a return to an unsettled weather pattern as a
relatively strong Pacific upper level trough for late June pushes
across the area late this week, with broad northwest flow after
the trough axis pushes east of the area Friday and next weekend.
Tuesday and Wednesday will be a transitional days under southwest
flow ahead of the Pacific trough. Models are not in the best
agreement with boundary layer moisture with the GFS showing gusty
westerly winds across all of southeast Wyoming and the southern
Nebraska Panhandle. The ECMWF and Canadian models show slightly
better moisture profiles, especially east of Interstate 25.
Current ensembles, including GEFS plumes, across the region show
the bulk of the ensemble members trending more towards the
GFS...with drier conditions and gusty westerly winds for most of
the day on Tuesday. Kept POP pretty low on Tuesday and Tuesday
night with values around 10 to 20 percent east of the Laramie
Range, and only around 30 percent further north where more
moisture will be present. Did note a subtle upper level vort
max/disturbance moving over the northern periphery of the upper
level ridge axis, so not comfortable completely removing the
mention of weather even as far south as the I-80 corridor. More
comfortable increasing POP on Wednesday and Wednesday night with
all models showing a backdoor cold front moving across the High
Plains and stalling near the Laramie Range by Wednesday evening.
Even though the timing is kind of uncertain, similar events
typically result in an earlier FROPA and substantial moisture
advection/convergence near and behind the front. In addition,
models are showing another upper level disturbance lifting
northeast across the area late Wednesday afternoon through late
Wednesday evening. So there is a possibility for nocturnal
convection due to MUCAPE above 1500 j/kg across most of the high
plains through early Thursday morning. All models are picking up
on this scenario with minor differences in location. So kept the
trend of increasing POP towards 50 percent through early Thursday
morning. Temperatures will be seasonably warm both days with highs
in the 80s. A few 90 degree temperatures are possible across the
lower elevations of the high plains. In addition, strong to severe
thunderstorms can not be ruled out later on Wednesday due to
substantial MUCAPE aloft and increasing 0-6km shear above 45
knots.
All models show the Pacific trough moving into the
Utah/Colorado/Wyoming region late this week with a good chance of
numerous showers and thunderstorms. Thursday appears to be the
best day for severe thunderstorms with MLCAPE between 1500 to 2500
j/kg and 0-6km shear above 50 knots. A potent shortwave ahead of
the main trough is expected to lift northeast across the area
during the afternoon. Kept increasing POP of 50 to 70 percent
across the bulk of the forecast area. Cooler temperatures are
expected with highs dropping into the 70s. All models show the
trough axis exiting the area to the east Friday afternoon, with
the upper level flow becoming northwest Friday through the
weekend. Expect below normal temperatures during this period with
a slow warming trend by Sunday. Showers and thunderstorms are
expected each day, especially across southeast Wyoming with some
stronger storms possible. Threat of flooding due to excessive
rainfall may return late this week and next weekend due to high
PW`s and training of storms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 541 PM MDT Sun Jun 25 2023
Terminals are likely to see VFR. Isolated VCTS will be present
through the early evening hours. VIS or CIGs are not expected to
be impacted. With low confidence of any -TSRA approaching a
terminal, decided to keep it out of most terminal forecasts with
the exception being KCYS. Winds should remain below 15-20 knots
for wind gusts through the forecast period.
&&
.FIRE WEATHER...
Issued at 315 PM MDT Sun Jun 25 2023
Slight fire weather concerns through Tuesday, with minimum
humidity and strong winds reaching critical thresholds for
Carbon County. However, with the fuel status remaining green
across the entire area, no fire weather headlines are expected.
Increase in low level moisture will begin pushing across the CWA
midweek, eliminating any additional fire weather concerns.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MRD
LONG TERM...TJT
AVIATION...BW
FIRE WEATHER...MRD
Area Forecast Discussion
National Weather Service Duluth MN
846 PM CDT Sun Jun 25 2023
.UPDATE...
Issued at 847 PM CDT Sun Jun 25 2023
Updated marine products to include a Marine Dense Fog Advisory
along the South Shore as area webcams are showing plenty of fog.
High resolution model guidance as shows good agreement in this
dense fog advecting inland into northwestern Wisconsin the
remainder of the evening through tonight. It is possible that
the dense fog gets as far inland as Washburn, Sawyer, and Price
Counties overnight, but confidence was not high enough at the
moment to include these counties in the land portion of the Dense
Fog Advisory.
&&
.DISCUSSION...(This evening through Saturday)
Issued at 513 PM CDT Sun Jun 25 2023
Summary: Rain showers and some isolated thunderstorms continue this
afternoon and overnight with better coverage over our far eastern
counties. No severe weather is anticipated at this time, however
excessive rainfall could lead to localized flooding. Northerly winds
stream back into the Northland tomorrow and will bring smoke both
aloft and at the surface. An Air Quality Alert is out for northern
MN. We will remain in an active pattern through the week with
additional chances for showers and thunderstorms.
Water vapor this afternoon highlights the cyclonic flow over the
region well the upper level low centered over SE MN. Surface wind
analysis suggests that the surface low has migrated slightly farther
NE into central WI. While cloud and smoke cover has been expansive
throughout the day we have managed to build in some weak instability
with MLCAPE values of a couple hundred J/kg. Very little bulk shear
is available so no severe weather is expected across the region.
Overall, another evening of scattered rain showers and isolated
thunderstorms will remain possible. The axis for heavy rainfall
potential is slowly shifting east as well. Heavy rounds of rain
could still be possible this evening which may lead to flooding
concerns in spots that have already been inundated with rain over
the last couple days. Based on the storm total estimates from the
radar we have a few pockets near Brainerd, Pine/Burnett counties,
and portions of the North Shore that have seen rain in excess of 4
inches.
Monday the low pressure system will have moved farther east into MI
leaving the region with cyclonic flow aloft. Return flow on the
backside of the exiting system combined with cold air advection
aloft should generate some additional showers and storms during the
day with decreasing likelihoods farther west. Northerly winds will
be streaming into the region as well and will spread smoke aloft and
near the surface. MPCA has northern MN under an Air Quality Alert
through Monday morning 9am. This may be extended farther south if
the HRRR trends continue.
The upper level pattern remains meridional through the rest of the
week with multiple chances for precipitation across the region.
Integrated water vapor transport highlights continuous moist
southwesterly flow into the region. This combined with additional
shortwaves and surface lows migrating across the northern Plains
will keep the weather active. The severe parameters through the week
do not look especially impressive as favorable CAPE and Shear
parameters fail to coincide based on the the 12Z guidance. Cluster
analysis shows varying degrees of strength across the 500mb so these
parameters will likely be in flux as we head through the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 638 PM CDT Sun Jun 25 2023
MVFR ceilings are present at TAF issuance for DLH, HIB, INL, and
HYR where lower cloud cover and scattered showers have moved back
in. Some breaks in the lower clouds are present at BRD. We do
expect ceilings to deteriorate to IFR for DLH, HIB, and INL and
MVFR for BRD by around 03Z this evening and persisting into 12-14Z
timeframe tomorrow morning given adequate low-level moisture and
spotty showers/drizzle persisting through the night. High
resolution model guidance does point to good signal for areas of
dense fog to move in from the lake into counties near the south
shore, with reduced visibilities and IFR to LIFR conditions
possible at HYR late this evening into tonight as a result. The
surface low departs to the southeast tomorrow and leads to
conditions improving back to VFR by the late morning/midday.
Some smoke may be possible near the surface across northern
Minnesota due to northerly winds advecting the smoke from Canadian
wildfires. These northerly winds could also reach gusts of 15 to
20 knots tomorrow afternoon across northern Minnesota and
northwest Wisconsin.
&&
.MARINE...
Issued at 840 PM CDT Sun Jun 25 2023
With weakening northerly winds and wave heights decreasing below 2
feet for the North Shore, and Duluth to Port Wing to Sand Bay,
have cancelled the Small Craft Advisory for these locations. The
advisory remains in place for the Apostle Islands into Saxon
Harbor due to higher wave heights lingering longer. Scattered
showers will continue at times through the overnight hours.
Additionally, have issued a Marine Dense Fog Advisory valid
through 9 AM CDT Monday for the South Shore nearshore zones where
visibilities of less than 1 NM will persist overnight.
Tomorrow, winds remain northerly. This will also lead to some
smoke aloft and near the surface to filter back across the Lake
from the wild fires up north.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 74 54 77 / 50 30 10 20
INL 54 78 54 81 / 40 10 10 50
BRD 59 79 56 83 / 30 10 0 20
HYR 55 70 49 81 / 40 40 10 10
ASX 53 68 51 75 / 60 60 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Dense Fog Advisory until 9 AM CDT Monday for WIZ001>004.
MN...None.
LS...Dense Fog Advisory until 9 AM CDT Monday for LSZ121-145>148-150.
Small Craft Advisory until 8 AM CDT Monday for LSZ147-148-150.
&&
$$
UPDATE...Rothstein
DISCUSSION...Britt
AVIATION...Rothstein
MARINE...Rothstein
Area Forecast Discussion
National Weather Service Des Moines IA
728 PM CDT Sun Jun 25 2023
...Updated for Near Term Weather Trends - High-level smoke...
Issued at 728 PM CDT Sun Jun 25 2023
Late afternoon and early evening visible satellite imagery along
with CIRA GeoColor and Day Cloud Phase Distinction RGB are
showing well an area of smoke that is wrapping in behind low
pressure that is nearing Lake Michigan. As WFO Omaha noted
earlier, there are some surface visibility restrictions generally
at or above 5 miles from Maryville, MO up toward the Omaha metro.
This visibility reduction area looks to scrap perhaps Taylor
county in our forecast area, but otherwise pass just southwest of
our forecast area. Thus, not planning to add any haze to the
weather grid at this time, but will monitor trends this evening.
Now, the latest RAP and HRRR smoke guidance shows a modest plume
of high-level smoke that will arrive overnight and translate
southward through Monday. So, have added some sky cover to account
for this. Some of this smoke will be hidden from view due to low
level clouds wrapping around the same low pressure tonight into
Monday, though that cloud cover should diminish over central into
eastern Iowa through the day Monday. Finally, there will be
additional high-level smoke behind this round Monday night into
Tuesday, but will pass onto the midshift to collaborate with the
latest guidance overnight. Otherwise, remainder of the near term
forecast remains on track.
As a general reminder, while we did increase sky cover to account
for high-level smoke this evening and can add haze or smoke to
the weather grid for surface impacts to visibility when
applicable, air quality monitoring and issuance of any air quality
advisories are the responsibility of our partners at the Iowa
Department of Natural Resources.
&&
.DISCUSSION.../Tonight through Sunday/
Issued at 251 PM CDT Sun Jun 25 2023
Forecast highlights:
- Windy until sunset, with shower activity and possible thunder
northeast
- Breezy again Monday but mainly quiet, isolated showers/thunder
northeast again
- Brief quiet period Monday evening through Tuesday afternoon
-Warmer with many chances of active weather through the rest of the
week and into the weekend
After a very active weather day yesterday, conditions have overall
quieted down. Despite this, the closed low pressure system as of
this afternoon remains in the Upper Midwest, centered over central
Wisconsin. Much of Iowa has been experiencing lingering cloud cover
on the backside of the system along with low level
northwest/westerly flow allowing for gusty winds. Winds have
generally been gusting between 25 to 35 mph, though at times higher
gusts over 40 mph have been seen in parts of northern and central
Iowa, where periods of brief mixing likely occurred where
insolation was able to reach the ground due to breaks in the
clouds, as seen from satellite imagery. The combination of cloud
cover and windy conditions has allowed for cooler temperatures in
the mid 60s to low 70s across much of the state, and in the mid to
upper 80s to the far south where more clearing is present.
Isolated showers to drizzle mainly over northern Iowa this morning
turned into more scattered shower activity across mainly the
northeastern part of the state. So far lightning has not been
detected with this rain, though models depict some instability
over the region largely under 500j/kg that may allow for some
thunder and a weak storm or two though would likely be
disorganized in nature given unfavorable shear profiles. Dry
weather is expected to return by the evening into the beginning of
the work week, with overnight lows falling in the upper 50s to
60s and winds relaxing a bit though remaining breezy due to the
tighter pressure gradient.
Fairly quiet conditions are expected Monday, though the
aforementioned low pressure makes quite the slow exit eastward.
Another area of stratus is expected to cover mainly the northeastern
half of Iowa, with another chance for diurnally driven showers and
possibly a weak storm or two again, though again no concerns for
severe weather are in place. The remainder of the state is expected
to remain dry with partly to mostly clear skies. Winds will increase
again by sunrise through the afternoon, though less gusty mainly
ranging between 20 to 25 mph. An area of ridging over the Northern
Great Plains will move eastwards into the Central Plains through
Monday into Tuesday, allowing for slight warming as temperatures
warm back into the upper 70s to 80s and dry weather to return across
the state by Monday evening.
A period of quiet weather with the ridge overhead is expected
through much of Tuesday, but looks to be short lived as models come
into better agreement of a mid level shortwave embedded in the upper
ridging pattern traveling down into the upper Midwest, bringing the
next chance for showers and thunderstorms Tuesday evening through
midweek. Overall, warmer temperatures in the 80s to low 90s with
increased moisture return is expected Wednesday through the
remainder of the work week. Deterministic models suggest moderate
instability over 1000-1500 j/kg and shear values in the 40-45 knot
range, indicating a higher potential of stronger storms, though are
not in good agreement on timing and location of any convection so
overall uncertainty is on the higher end of the scale. Overall, it
does not look like widespread long lasting convection, but rather
hit or miss depending on where development and movement occurs. Will
have to keep a close eye on this over the next few days to allow
time for better consensus.
Active weather generally looks to remain in the forecast through the
remainder of the work week and into the weekend as a larger trough
swings out of the western CONUS into the region, before slightly
cooler and drier conditions look to return.
&&
.AVIATION.../For the 00Z TAFS through 00Z Monday evening/
Issued at 641 PM CDT Sun Jun 25 2023
Lingering shower activity will dissipate early this evening with
VFR conditions prevailing the rest of the evening. After midnight,
MVFR stratus will wrap around low pressure that is nearing Lake
Michigan into roughly the eastern half or so of Iowa, including
MCW and ALO. This stratus may graze FOD and come close to DSM and
OTM, but have left out any mention due to low confidence at this
time. The ceiling restrictions should improve into Monday
afternoon. Gusty winds will diminish slightly overnight, but
remain elevated with blustery winds from the northwest prevailing
tomorrow.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Ansorge
DISCUSSION...Bury
AVIATION...Ansorge
Area Forecast Discussion
National Weather Service Grand Forks ND
1013 PM CDT Sun Jun 25 2023
.UPDATE...
Issued at 1013 PM CDT Sun Jun 25 2023
We still have a few stubborn showers lingering northwest MN, but
trends are on track with this activity rapidly decreasing in
covearge along with the lower stratus sliding south and southeast
with the arrival of drier BL air. Surface smoke is being reported
now as far south as Grand Forks and this matches the trends in
the RAP near surface smoke field. While the source region gets
cutoff eventual when flow shifts more to the northwest the trapped
smoke already advecting into the region will tend to linger until
it is mixed out during the day Monday. Patchy smoke was added to
the forecast to capture these trends and additional adjustments
were made to PoPs to delay the end of showers this evening for a
few more hours.
UPDATE Issued at 644 PM CDT Sun Jun 25 2023
There are still reports of light rain within the area of low
stratus in our east, but as the main system continues to slide
east and we loose daytime heating this should gradually clear
with drier/stable air mass returning. There are a few
thunderstorms that popped along a convergence zone to the west,
but mean flow wouldn`t support this moving into our northwest
before sunset when it should weaken/fall apart.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 250 PM CDT Sun Jun 25 2023
Key Messages:
Showers and isolated thunderstorms are possible this afternoon and
evening.
Severe storms are not expected.
Through the remainder of today and into Monday, look for a
continuation of partly to mostly cloudy skies, along with
temperatures in the 70s today and lower 80s Monday. Precipitation
chances remain in the forecast, albeit without much in the way of
strong thunderstorm potential.
Shortwave ridging traverses the area starting late Monday, followed
by a more zonal flow pattern that is expected to persist well into
next week. Monday afternoon will bring CAPE values upwards of 1500
J/Kg; however, this instability will exist in the absence of deep
layer shear, thus limiting the chances for strong to severe
thunderstorm activity. Nonetheless, a few thunderstorms will still
be possible as a weak shortwave pushes across the northern portions
of Monday`s H5 ridge.
.LONG TERM...(Tuesday through Sunday)
Issued at 250 PM CDT Sun Jun 25 2023
Key Messages:
An unsettled pattern prevails next week as zonal flow takes shape
across the Northern CONUS.
The potential for severe thunderstorms is limited Monday through
Wednesday, with a more favorable setup Wed through Sat.
H5 ridging over Texas is expected to flatten as we progress through
the work week. This will allow lower H5 heights across north-central
Canada, and a resultant split flow for the western Conus. For the
Northern Plains, we can expect zonal flow, which will usher several
shortwaves across the region through the end of next week. CAPE
values climb to near 2000 J/Kg each day Monday through Wednesday,
with deep layer shear being relatively weak. Shear increases as
stronger shortwaves / upper lows begin to form in the western
Canadian Plains, then travel southeastward into the Northern Plains.
This pattern begins to take shape mainly from late Wednesday onward
into the weekend.
The potential for strong to severe thunderstorms is indicated for
much of the second half of next week. With antecedent instability
and slightly increased deep layer shear, we could see an uptick in
thunderstorm activity as next week progresses. It is too soon to
determine the timing and placement of any potential activity, as
this will hinge upon the timing of the upper low.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 644 PM CDT Sun Jun 25 2023
Lingering light rain showers and IFR/MVFR stratus in northwest MN
should continue to clear west to east this evening as the
associated system continues to move east of the region. Wild fire
smoke is already filtering into the region due to northeast flow
and smoke models indicated that near surface smoke may settled
across northeast ND and parts of northwest MN later tonight
through the early morning hours Monday before clearing. Upstream
rends generally show vis at 6 miles or greater where this smoke
is being reported, however brief drops to MVFR can`t be ruled out.
Otherwise, northerly winds should decrease with surface high
pressure building into the region with light/variable winds 5kt or
less overnight into the Monday morning period. A gradual increase
from the northwest 5-10kt is shown by the afternoon during peak
daytime heating.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...DJR
SHORT TERM...Lynch
LONG TERM...Lynch
AVIATION...DJR
Area Forecast Discussion
National Weather Service Gray ME
759 PM EDT Sun Jun 25 2023
.SYNOPSIS...
A warm muggy night with areas of fog and showers will be in
store for tonight. On Monday a backdoor cold front moves through
cooling things off significantly while the chances for showers
still exists. This front stalls across the area Tuesday,
lifting back north as a weak warm front. Thunderstorms will be
possible Tuesday afternoon before continued unsettled weather
through mid and late week.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
755 PM...TSRA have been developing along weak moisture boundary
across central NH and W ME late today /Ts mid 60s N, and low
70s S/. Some of this storm have been very slow to move with
heavy rain, so there remains a threat of some localized flash
flooding through about 02Z with any of the storms, otherwise,
look for to develop late this evening and overnight, and it
could be dense in some spots especially near the coast. Lows
will mostly be in the 600s, around 60 in the ME mtns, to the
mid to upper 60s in central and srn NH.
Previously...A very warm and muggy air mass remains in place
across the forecast area of this this Sunday afternoon. However,
radar not looking impressive as only widely scattered showers
have developed thus far in an area of short wave ridging. As
such, we have lowered PoPs for the next several hours. Those
that do see a brief shower or thunderstorm will likely get a
short-lived intense downpour.
The wildfire smoke in the western ME mountains has been quite
impressive today with vsbys at times 1 mile or less. The air
quality alert remains in effect through this evening. Have kept
smoke in the forecast through tonight based on latest HRRR low
level smoke progs.
Later on this evening the short wave ridge that is currently
overhead will break down some as a short wave trough approaches
from the NYC area. Despite the loss of daytime heating, we
think the developing weak forcing for ascent in this very moist
air mass will allow for perhaps a resurgence of showers and
perhaps a thunderstorm overnight. Kept PoPs going. Any slow
moving or training storms could produce isolated flooding.
Fog will likely move back in tonight and portions of the
forecast area may need a dense fog advisory.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
High pressure building southward out of northern New Brunswick
will send a back door cold front across out region late tonight
and Monday. Winds go easterly and has a result high temperatures
and dewpoint levels will be much lower on Monday, especially in
Maine. Moist overrunning will be the cause for more shower
activity on Monday with plenty of clouds. The same is in store
for Monday night.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Overview: Moist, humid airmass stays in place, with a few
chances for thunder. Main concerns will be continued rain in
basins that remain damp, which could lead to localized flash
flooding and rising rivers.
Details: Tuesday may harbor a strong storm threat, but there is
considerable uncertainty surrounding available surface
instability and a lifting mechanism.
With southerly 850mb poleward jet just to the east Tuesday, low
level 0-1km shear and deep layer shear will both be supportive
for organized cells. It goes without saying that moisture
should also be substantial considering the IVT channel flooding
up the east coast and into the Canadian Maritimes. Come late
morning and afternoon with these shear and moisture elements
still in play, focus turns towards instability or lifting
elements. With mostly unidirectional flow and little notice of
passing shortwaves within the flow, there will be limited lift
other than any differential heating taking place. There may be a
capped interface along the ME/NH border that could harbor some
of this lifting capability, as well as southerly flow butting
against the White Mtns. QPF guidance does highlight these
mountain faces for local enhancement, so focus hones in on the
southern half of NH for strong storm potential. As mentioned,
there will be a light cap that will need to be beaten before
deeper convection takes place, so have kept larger thunder
chances where this may be thinnest. Elsewhere, elevated
instability remains, but in light amounts that only constitute a
slight chance.
Should a stronger storm develop, main threats would be very
heavy downpours and perhaps hail. There is a fluctuating area of
helicity values in the early afternoon and again during the
evening. SHERB values also approach 1 in a potential high CAPE
low shear environment. This may contribute for a quick spinup
should organized convection develop, but before considering this
a noteworthy threat, will monitor CAM guidance when it is in
range.
Shower and rain coverage will continue to be instability and
forcing driven Tuesday night through Wednesday. This will make
some locations rich with moisture, and some simply with passing
showers over the period under threatening skies. Locations that
could see these more persistent rains will be upslope regions of
the mountains and any additional convergence or lift generated
along the coastal front if the interior can warm enough. The
next more consistent rain may approach NH Wednesday afternoon.
The remainder of the forecast sees unsettled weather continue,
but the channel of deeper moisture does wane into late week.
Will need to watch for any additional shortwaves rounding the
descending low as these could bring more concentrated periods of
rain in an otherwise showery pattern. Overnight fog will be a
near certainty over land and coastal waters.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Short Term...Tonight will once again see areas of fog that will
likely bring IFR to LIFR restrictions. The unsettled pattern
continues Monday with likely some improvement in conditions
during the day with chances for SHRA.
Long Term...MVFR to IFR set to continue through Friday with low
ceilings and patchy fog during the mornings, overnights, and
evenings. LIFR will be possible as well. Chance for more
persistent daytime fog will be in vicinity of the coast. TS
chances increase Tuesday across much of NH, with lesser chances
for ME. Otherwise SHRA and RA continues.
&&
.MARINE...
Short Term...Winds and seas remain below SCA thresholds while
a moist southerly flow pattern continues in tonight. A backdoor
cold front will move cross the waters later tonight brining
northeast winds for Monday.
Long Term...SCA may be needed Tuesday afternoon through mid-week
as southerly wind fetch builds waves toward 5 ft on the coastal
waters. Winds will near 30 kt on the outer waters, into
Wednesday, but widespread gusts of that speed will be limited.
Swell may also increase towards late week with low pressure
pushing north in the open Atlantic.
&&
.HYDROLOGY...
A very moist air mass in place along with very weak steering
flow will allow for very slow moving showers and thunderstorms
tonight. This may allow for localized flash flooding.
Continued unsettled, moist pattern will lead to showers and
storms in the region this week. Breaks in between more
persistent rains will help keep a more widespread flood threat
low, but river rises are expected through the week, some
approaching or surpassing minor flood stage. Of greater
confidence will be flashy tributaries of the Merrimack River
(Pemigewasset, Suncook, etc) and the Saco/Swift in Maine.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
SYNOPSIS...
NEAR TERM...Cempa/Ekster
SHORT TERM...Ekster/Schroeter
LONG TERM...Cannon
AVIATION...
MARINE...
HYDROLOGY...
Area Forecast Discussion
National Weather Service Jackson MS
1030 PM CDT Sun Jun 25 2023
...New MESOSCALE UPDATE...
.MESOSCALE UPDATE...
Issued at 1017 PM CDT Sun Jun 25 2023
Thunderstorms continue to push southward across the area this
evening and although they have weakened some over the past hour or
so, there continues to be at least some strong to severe potential
as they continue to trek southward. SPC has issued another Severe
Thunderstorm Watch for the remaining southern counties in our area
until 4 am. Dewpoints remain in the mid/upper 70s for areas along
and south of the storms, along with a decent amount of
shear/instability. The HRRR tries to develop additional
thunderstorm activity over the northern portions of the area
overnight, but some of the remaining Hi-Res models keep this
activity to our west. With much of the area being worked over with
the current thundestorm activity, will lean towards the ARW,
which keeps any additional thunderstorm development mainly in the
west overnight./15/
&&
.MESOSCALE UPDATE...
Issued at 718 PM CDT Sun Jun 25 2023
Severe thunderstorms are beginning to move into the Delta this
evening and expect them to continue to move southeast through the
evening hours. The storms may begin to weaken as they move closer
to the I-20 corridor, where strong capping is in place. SPC has
issued a Severe Thunderstorm Watch for areas along and north of
the I-20 corridor until 2AM. The main risk will be damaging wind
gusts and quarter size hail with these storms./15/
&&
.DISCUSSION...
Issued at 226 PM CDT Sun Jun 25 2023
Rest of today through Monday...
Warm & humid afternoon will transition into an active period of rain
& storms into the evening to overnight hours. The upper level high
remains over the Rio Grande, while the region remains just in the
wake of the upper level trough axis just to the east. MCS is
currently diving down over the TN Valley into northern GA & will
remain well northeast. Anomalous low-level thermo profiles (i.e.
925mb & 850mb in the low 20s deg. C) indicate potential to warm
efficiently with plenty of insolation & highs will peak in the low
90s northeast while mid 90s elsewhere. GOES East total PWs &
regional 12Z soundings indicate moisture advection has helped PWs
climb to closer to an inch & three quarters or so. This is helping
to limit mixing somewhat, with some dewpoints around the 72-75
degree range but others remaining in the upper 70s into the late
aftn into evening. Dangerous heat stress persists for most of the
area. Heat was a little more expansive so filled in the rest of the
area with an advisory for today.
Main concerns remain the increased severe potential this evening
into the overnight. 12Z synoptic analysis indicates upper jet max
ejecting through the Plains & this speed max is progged to gradually
shift east-southeast into the evening. As increased dynamic ascent
occurs, combined with high destabilization, will favor increased
upscale storm growth. Models struggled with initialization of the
cool thermo aloft, with nearly -10 deg at 500mb. 12Z modified JAN &
LZK soundings indicated potential for 3600-4900 J/kg y, 1300-1800
DCAPE, vertical totals of +31 deg. C & LIs of -13 to -15. The
microburst composite parameters peak well in the likely category,
which shows >50% probs for +5 storm events. This extremely
destabilized environment won`t fully be tapped into this aftn,
outside of some convergent showers or isolated storms in the Golden
Triangle through late aftn. Any developed MCS progged to dive down
from the northwest from the Ozarks in AR should be robust into this
evening. Increased & agitated cumulus growth in eastern OK into the
Ozarks along the front look to be the main area of storm impetus
this evening. CAMs are finally picking up on this potential & it
should be moving into the Hwy 82 corridor just after 6-9PM, 7-11PM
in the Natchez Trace corridor, Interstate 20 corridor around 10PM-
1AM & Hwy 84 corridor by 2-4AM. Strong mean bulk shear of +25-30kts
in the 0-3km/0-6km layers, respectively, will help organized
storms/cold pools propagating quickly southeast. There could be some
redevelopment in the wake but how scoured out the environment is by
the MCS is uncertain. The Enhanced Risk remains with hazards of
widespread damaging wind potential of 70-80mph, quarter size hail or
potentially briefly larger & a tornado can`t be fully ruled out.
HRRR wind gust swath maps indicate the potential severe wind gusts
swaths could reach the Interstate 20 corridor but will gradually
lose steam as it propagates southward.
Expect rain & storm chances to clear out tonight while some may
persist in east-southeast MS through midday. With similar anomalous
warmth in thermo profiles, highs will be similar but could be
slightly cooler in the Hwy 82 corridor in the wake of the frontal
passage. Heat indices could still reach near heat advisory criteria
areawide, so kept a Heat Advisory going again from 11AM until 8PM
Monday. The Significant remains over portions of northeast
Louisiana, western, central to southeast Mississippi. Heat indices
could peak above 110 deg. F, so if trends persist, an areal upgrade
to Excessive Heat Warning will likely be needed in future forecast
packages. /DC/
Monday Night through the weekend...
Lingering showers and thunderstorms could occur across central
Mississippi, mainly east of I-55, by late Monday night as the main
bulk of convection continues to push further east towards Alabama.
This should allow for quiet conditions to settle across the
southeast United States on Tuesday morning as model guidance
continue to show the midlevel high over Texas and the trough slowly
shifting eastward towards the upper East Coast. Rain chances could
sneak back into the area around the Wednesday timeframe thanks to a
small disturbance traversing along the eastern section of the
aforementioned high with dewpoints reaching the upper 70s. This
could allow for isolated showers and thunderstorms to occur across
central Mississippi mainly along and east of I-55.
Dangerous heat stress remains a primary concern for the rest of the
work week. Both the GFS and the ECMWF continue to show surface
ridging spreading across the eastern CONUS as the sfc high shifts
east towards the ArkLaMiss region. This high should limit any
moisture flow form the Gulf, thereby prohibiting any convection from
forming. As we head later into the week, there is higher confidence
that afternoon temperatures could reach in the low 100s across our
forecast area with heat indices forecasted to reach up to 115
degrees with higher values possible. Given the near record high
temperatures later in the week and overnight lows only falling in
the mid to upper 70s, significant to extreme heat stress conditions
are expected for the entire southeast region. An Excessive Heat
Warning may be issued later in the week if current trends continue.
Make sure to stay hydrated and take frequent breaks if working
outdoors. Rain chances could sneak back into the area by the weekend
as the sfc high being to unravel. This should give us some relief
from the heat as afternoon highs return to seasonal norms. /CR/
&&
.AVIATION...
(18Z TAFS)
Issued at 130 PM CDT Sun Jun 25 2023
Chances for SHRA & TSRA increase from north to south after 26/00Z
Monday as a line of storms moves south with strong & gusty
northerly winds, some gusts in excess of 40-50mph psbl. Most
likely window for impacts have been updated in the 18Z TAF cycle,
from 26/01-03Z at GLH, GWO & GTR, 26/03-06Z at HKS, JAN & MEI &
26/05-08Z at HEZ, PIB & HBG. Some continued chances for SHRA &
vicinity TSRA are psbl after line of storms clear. MVFR cigs are
psbl just before daybreak at JAN, HKS but most likely at HEZ, PIB
& HBG, so added tempo MVFR flight categorical reductions near or
just after daybreak Monday. /DC/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 96 75 95 75 / 10 60 30 30
Meridian 96 74 95 74 / 20 50 40 30
Vicksburg 97 75 96 76 / 10 60 20 20
Hattiesburg 96 75 96 76 / 10 40 30 20
Natchez 96 75 96 76 / 10 20 20 10
Greenville 96 73 94 74 / 10 70 20 20
Greenwood 96 74 95 74 / 20 50 20 20
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Heat Advisory from 11 AM to 8 PM CDT Monday for MSZ018-019-
025>066-072>074.
LA...Heat Advisory from 11 AM to 8 PM CDT Monday for LAZ007>009-015-
016-023>026.
AR...Heat Advisory from 11 AM to 8 PM CDT Monday for ARZ074-075.
&&
$$
15/
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
907 PM EDT Sun Jun 25 2023
.MESOSCALE DISCUSSION...
Issued at 907 PM EDT SUN JUN 25 2023
...SEVERE RISK LATER THIS EVENING/EARLY OVERNIGHT, I-75 WESTWARD
MOST STRONGLY FAVORED...
Strong low-level capping, evident in the 18z sounding from ILN, in
the wake of a weak MCS earlier in the day has kept convection at bay
over eastern Kentucky through the afternoon and much of the evening.
Regional radar now shows the remnants of former showers and storms
moving into the northwestern one third of the CWA, but this activity
is struggling to maintain more than moderate radar returns as it has
apparently lost its surface-based characteristics. Dew points over
most locations east of I-75 are in the mid and upper 60s but range
through the 70s further west. This corresponds well with instability
which ranges from barely a 1000 J/kg of MLCAPE along the Virginia
border to 2,000 J/kg+ over southcentral Kentucky.
The latest mesoanalysis shows the cold front dropping across the
Lower Ohio River. Convection is initiating and consolidating into
a line just ahead of the front where the low-level capping is
minimized. A theta-e ridge axis extends from Western/Middle
Tennessee northward into western and central Kentucky just ahead
of this convection. Meanwhile, dry air in the mid-levels is
leading to cold downdrafts which are likely consolidating into a
cold pool under the ongoing convection across the Lower Ohio
Valley. Latest HRRR and 18z NAMNEST guidance shows the ongoing
convection becoming cold pool driven, and dropping southward into
the aforementioned theta-e ridge axis (where there is the
greatest instability -- fuel for the storms).
For our CWA, the best combination of instability and shear, favors
the strongest thunderstorm activity occurring in counties along and
and west of I-75. Damaging winds remain the primary hazard with
gusts of 60+ mph a concern west of I-75. East of I-75,
considerably greater capping/PBL stabilization and less
instability aloft will favor weaker showers and storms, although
isolated to perhaps widely scattered instances of severe weather,
primarily wind, cannot be ruled out. Additionally, a brief spinup
tornado or severe hail (1 inch or greater diameter) cannot be
ruled out with any rotating updrafts; however, the anticipated
linear cold-pool driven nature of this convection should limit
this potential. Progressive storm motion should minimize the
potential for high water concerns, though an isolated instance of
high water cannot be ruled out as well.
&&
.UPDATE...
Issued at 810 PM EDT SUN JUN 25 2023
Some uncertainties remain with the evolution of convection this
evening into the overnight hours. Convection earlier today led to
some stabilization across the region and a cap near the 850 mb
level, though late day sun led to some recovery, especially in the
west and northwest. CAMS have struggled a bit with the convective
trends upstream. A more robust cell southeast of LMK in central KY
appears headed toward the southwest portion of the CWA over the next
few hours as it holds together, while additional convection has
developed closer to the front in a more unstable environment
somewhat in line with some of the recent HRRR runs.
MLCAPE and MUCAPE are greater in locations further west where more
heating occurred and dewpoints are in the upper 60s to near 70
and southwestern portions of the area are nearer to a gradient in
CAPE. Adequate shear is anticipated as the front and mid level
shortwave approach late this evening into the overnight, with a
decrease in instability for locations further east. The more
robust convection should generally affect western and southwestern
locations where HREF probabilities are greater and CAMS have more
UH swaths, though wind gusts capable of some damage will be
possible further east. The primary threat from convection remains
wind.
Some adjustments to pops have been made based on recent radar and
convective allowing model trends.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 614 PM EDT SUN JUN 25 2023
Key Points:
* Severe weather threat this evening into the overnight hours.
* Damaging wind gusts remain the primary threat, with large hail
and an isolated tornado or two also possible.
The latest upper level map features a very strong ridge centered
over northern Mexico, with unseasonably strong low pressure found
churning over southwest Wisconsin, with an arced short wave trough
aligned north to south from Michigan through eastern Indiana. At
the surface, low pressure is seen across eastern Wisconsin, with
an occluded front arcing south, before a cold front takes over as
it drapes southwest through southern Illinois and then southwest
into portions of Missouri. Deep convection is firing out ahead of
the front and upper level support. An outflow boundary from an
earlier day complex of thunderstorms is positioned north northwest
to south southeast across the western half of the Commonwealth.
Clearing skies late in the day has allowed for some recovery
across eastern Kentucky, with temperatures currently ranging from
the upper 70s to lower 80s.
The models remain in good agreement aloft through the short term,
with low pressure gradually spiraling its way east across the
Great Lakes, reaching Lake Huron by the end of the period, and
reestablishing a deeper trough from the eastern Ohio Valley down
through the southeastern CONUS by that time. At the surface, low
pressure will remain nearly stacked underneath its upper level
counterpart, with a cold front to push southeast through the Ohio
Valley tonight into Monday, and then through the Deep South by Monday
night. Robust convection looks to take aim at eastern Kentucky
this evening into tonight, with most of the activity diminishing
in the pre-dawn hours. A few showers and storms will refire across
locations north of the Mountain Parkway Monday afternoon, with
additional scattered convection threatening further south and
southwest, as a secondary surface trough and upper level support
rotate through Monday night.
At least moderate instability of 1500-2500 J/kg MU CAPE, along
with moderate to strong bulk shear of 40-55 kts build back into
the region through this evening. CAMs have been showing varying
solutions with the evolution of the convection, but in general
continue to show a transition from more discrete cells that are
currently ongoing, to more clusters or lines as this activity
approaches our area. This would continue to favor more of a
damaging wind threat, especially if storms can align more
perpendicular to the 0-3 km bulk shear vectors, or more northeast
to southwest oriented. Embedded large hail will also remain
possible within the most robust updrafts. Additionally, given the
increasing low level jet through the night, allowing for a
notable uptick in both 0-1 km and 0-3 km SRH, this will support
at least an isolated tornado threat, most likely in the form of a
QLCS. The area of greatest concern continues to be more along the
I-64 corridor, and perhaps even more so across locations along
and west of I-75, which will likely see the best combination of
better instability and shear eventually returning. Storms will
gradually fizzle as they spread southeast with time, likely
exiting before dawn.
The cold front will pass through on Monday, with temperatures
still rebounding into the lower 80s, and the threat of at least
isolated convection in our north by the afternoon, given the
ongoing cyclonic flow associated with the Great Lakes upper level
low. Convection will continue to threaten Monday night, as the
aforementioned secondary surface trough pushes southeast out of
Ohio. Lows both tonight and Monday night will average in the mid
60s.
.LONG TERM...(Tuesday through Sunday)
Issued at 515 PM EDT SUN JUN 25 2023
Better than usual agreement in synoptic model solutions leads to
a fairly straight forward forecast...and discussion. Seeing a
pattern shift aloft for the Upper 48. Ridging over the central
U.S. will succumb to shortwave energy phasing across the Northern
Tier and northern/central Plains through the period, and the
eventual evolution of a trough over the Upper Midwest and Great
Lakes by the end of the extended.
Sensible weather features relatively benign weather to start out
the extended. System will be exiting the Ohio Valley with a
surface cold front well to our south. A post frontal trough may be
organized enough to generate a few showers and thunderstorms
Tuesday afternoon but there appears to be a trend towards a little
lower PoPs. Ridging aloft and high pressure at the surface will
keep PoPs minimal through much of the week. As high pressure
shifts eastward late in the week, return flow will allow for
moisture to increase across the region, and along with that an
increase in the threat of rain, though we are still only looking
at low to slight chance PoPs (20-30%), near climatological summer
time levels. PoPs increase more substantially as the weekend
approaches and our next system rides in from the west, lifting a
surface warm front across eastern Kentucky on Friday. This system
will keep a higher threat of rain in the forecast through the end
of the forecast window, and likely just beyond. Temperatures
rebound strongly as this warm front lifts northeast through and
out of the area, with afternoon highs climbing from seasonable mid
80s through the mid-week time frame into the 90s for Friday and
Saturday.
Not seeing any strong signals for hazardous type weather, other
than some warm temperatures for the end of the extended. Dew
points climbing into the 70s will make for some uncomfortably
muggy weather. Summer finally arrives? Strong diurnal heating and
marginal shear combined with ample surface moisture could be the
right mix of ingredients for some stronger storms by the end of
the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 819 PM EDT SUN JUN 25 2023
VFR conditions are expected initially at all TAF sites. However,
convection over central KY and in advance of a cold front will
approach and likely affect a good portion of the region during the
first 6 hours of the period departing to the southeast by around
09Z. These storms will likely bring periods of MVFR if not a
period of IFR or worse conditions at the terminals as they pass
through the area, generally between 01 and 06z. Wind gusts of 35
to 45 kts or greater will occur with the more intense storms, with
recent rends suggesting that KSME, KLOZ, and possibly KJKL having
the greatest chance of experiencing these stronger winds.
However, these have not been included in the TAFs due to
uncertainty. Once the storms pass through, clouds will generally
scatter out, with a return of VFR conditions. Outside of storms,
winds should average from the southwest at 10KT or less during
the first 12 hours of the period, before becoming more westerly
near 10KT during the last 12 hours of the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE...GEERTSON
UPDATE...JP
SHORT TERM...GEOGERIAN
LONG TERM...RAY
AVIATION...JP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
902 PM CDT Sun Jun 25 2023
.UPDATE...
Issued at 902 PM CDT Sun Jun 25 2023
Mostly cloudy skies covers the area as the center of low pressure
continues to spin over Eastern Wisconsin, scattered showers continue
to pass over from west to east on radar. Most of the showers this
afternoon were fairly shallow producing light rain. While the
environment is not wholly unstable, mesoanalysis shows increased
level of CAPE north and west of I-55 which has helped uptick the
showers slightly. Some of the cells that have developed over the
last few hours produced moderate to heavy rain, notably at Chicago-
Midway which received just over a third of an inch in just about 15
minutes as a cell passed directly overhead. There was also some
upscale growth for the cells to the west that has developed some
lightning and thunder, but has since subsided. As showers in
southwestern Wisconsin move southeastward, the scattered shower
activity will continue for the next couple of hours and gradually
diminish over night.
The low will very gradually move eastward into the Michigan Mitten
on Monday. Hi-res guidance shows a renewed effort of scattered
showers on Monday. Chances for rain will be present across northern
Illinois, the highest likelihood for showery activity will be for
areas in counties along the lakeshore, which are closest to the
center of the low. The HRRR is starting to also come into line with
the NAM Nest that shows increased levels of instability and dew
points in in the 60s, particularly over northwest Indiana, Monday
afternoon where storm nuclei can once again develop and strengthen.
The overall environment does not lean toward severe storms, but the
main concern will be showers that produce strong enough wind gusts
that may be in excess of 30 mph.
DK
&&
.SHORT TERM...
Issued at 244 PM CDT Sun Jun 25 2023
Through Monday night...
Now that this morning`s cold front has passed off to our east, we`re
mainly just looking at some scattered shower chances over the next
day or so. Some light, scattered showers are beginning to swing
around to the southern periphery of the low and fall on parts of far
northwestern IL early this afternoon. Behind the front, our area was
robbed of most of our moisture but, where these showers are
currently popping up out west, a plume of ample low-mid level
moisture is approaching and will allow for these showers to persist
as they move through the area over the next several hours. The
better rain chances for the rest of today appear to be across far
northern IL where the low level jet is moving a bit quicker and a
greater deal of vorticity exists closer to the center of the low.
Latest model data suggests that we will still be able to work in a
few hundred joules of CAPE by late this afternoon thanks to the
filtered sunshine that we`re seeing and the aforementioned low level
moisture advection working its way into the area. So, while we`re
not necessarily expecting any thunderstorms the rest of the day,
it`s not out of the realm of possibility that a few low-topped
thunderstorms could develop later in the day.
Scattered rain chances will continue through tonight, although we
will likely see rain coverage lessen as we begin to lose out on
moisture and synoptic forcing dampens, especially away from the
Chicago metro. However, we are expecting another plume of low-mid
level moisture to swing around the low and feed into the area
beginning Monday morning. Forcing will also go back on the mend with
another push of enhanced low level flow progged to drop into the
area later in the day. Despite mostly cloudy skies and cooler
temperatures with highs in the 70s, dewpoints in the lower 60s will
aid in building a few to several hundred joules of CAPE through the
afternoon. The skinny, elongated CAPE profile and rather poor lapse
rates shown on forecast soundings don`t look conducive of any robust
updrafts. However, it looks likely that at least a few thunderstorms
will fire up during the latter part of the afternoon and evening.
Thunder chances will dwindle through the evening with rain chances
fizzling away from west to east tomorrow night. Additionally, the
windy conditions this afternoon will come down some but remain
breezy for tonight as we`re expected to never fully decouple and
continue mixing into some of the stronger winds found just off of
the surface. Winds will ramp back up a bit through the day tomorrow
with 25+ mph gusts expected through the afternoon.
Doom
&&
.LONG TERM...
Issued at 239 PM CDT Sun Jun 25 2023
Tuesday through Sunday...
Primary forecast concern is thunderstorm chances later this week
along with their timing and severe possibilities.
Additionally, high waves may create dangerous swimming conditions
at Lake Michigan beaches Tuesday/Tuesday night.
The upper low will still be slowly shifting east across the
eastern Great Lakes on Tuesday. Most of the area should remain
dry on Tuesday though there could still be some lingering showers
over the lake and far northwest IN, mainly Tuesday morning. High
temps on Tuesday will likely rebound into the lower 80s inland,
but areas near the lake will likely remain in the 70s.
Winds will turn northerly Tuesday, though will likely be
diminishing during the afternoon and evening as a ridge of high
pressure moves across the region. Waves will build on Tuesday,
possibly into the 4-6 foot range, especially for northwest IN.
Thus, dangerous swimming conditions will likely develop and a
beach hazard statement will likely be needed with later forecasts.
Focus then shifts to an expected ridge building across the central
U.S. and various disturbances that will be moving across the local
area, mainly in the Thursday to Saturday time period, at least as
trends look now. Though its fairly difficult to have any
confidence in more detailed timing from this distance. And precip
chances later in the period, will likely be at least somewhat
dependent on earlier precip chances. Opted to cap blended pops at
40 percent for now given the uncertainty and the fact that there
will be many dry hours. With high temps possibly back into the
upper 80s/lower 90s inland, depending on precip trends, and
dewpoints possibly back into the 60s, any wave transversing the
ridge will likely be able to tap into this instability and have
some severe potential though similar to timing, just too early
with too much uncertainty to mention at this time.
Models are hinting at another cool front moving across the Great
Lakes area next weekend, possibly with another upper low over the
northern Great Lakes. If this were to materialize, thunderstorm
chances would likely be pushed south and east of the area with
more seasonable temps. cms
&&
.AVIATION...
For the 00Z TAFs...
Aviation Forecast Concerns:
* Gusty west winds persist with gusts 25-30 kt early this evening
easing to 20-25 kts remainder of period.
* Scattered convective showers this evening and again Monday
afternoon. Non-zero lightning threat Monday afternoon, but only
isolated TS coverage expected. Brief MVFR/high IFR vis in
heavier showers.
* MVFR ceilings expected to develop after midnight tonight and
linger through Monday.
Relatively deep surface low pressure was located over east-central
WI early this evening, with a cold front off to the east of the
forecast area through lower MI/IN/lower OH Valley. This low was
associated with a deep mid-level disturbance which will track
slowly east across the region through Monday night. Moisture
wrapping around this disturbance from the northwest will result in
considerable cloud cover during the period, with ceilings
settling to MVFR (~1500 feet) after midnight tonight and
persisting into Monday before slowly lifting above 2000 feet later
in the day and evening. Scattered convective showers will affect
the terminals this evening before waning late, though diurnal
heating will renew scattered shower and isolated thunderstorm
development again Monday afternoon. Thunderstorm coverage looks to
be low enough at this distance to not include in the TAFs, though
there will be at least some lightning potential Monday afternoon.
Visibilities may briefly drop to high-end IFR/MVFR in individual
showers/clusters.
Otherwise, westerly winds will gust near 30 kts early this
evening, easing to 20-25 kt overnight. Winds will gradually shift
northwest by Monday afternoon and evening, with gusts around 25
kts (or perhaps a few knots higher) especially during the warmer
afternoon hours. Northwest winds will gradually Monday night.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Morristown TN
944 PM EDT Sun Jun 25 2023
...New UPDATE...
.UPDATE...
Issued at 930 PM EDT Sun Jun 25 2023
The earlier round of convection has exited, but strong convection
is getting going near the Ohio River and latest guidance still
suggests an arrival time over our northern Plateau counties of
sometime around the 05-06Z time frame. Will be making slight
adjustments to slow the forecast arrival time with this update
but overall PoPs/Wx depiction still looks good. No major change in
thinking on the severe threat, with hail and damaging winds
expected to be the main threats. Only other changes with this
update will be to bump temperatures and dew points down based on
latest observations.
&&
.SHORT TERM...
(This evening through Monday night)
Issued at 235 PM EDT Sun Jun 25 2023
Southern sections will be under the gun for damaging winds and
heavy rain over the next few hours. The current orientation of the
storms NW-SE along a boundary suggests training cells that could
produce localized flooding problems. Once this activity exits, we
will have a period of calm and clearing skies through the evening.
The convection now developing in IN is expected to develop into a
MCS that will track SE through the night. The recent CAMS runs
have reasonably decent agreement on the timing of this MCS into
the Plateau and SW VA, likely around 05-06Z. The main concern with
these storms will be large hail. Model soundings continue to
indicate very steep lapse rates above a stable boundary layer.
There will be a strong 40+ kt LLJ advecting high theta-e air at
the top of the low level inversion, around 800 mb. This results in
MUCAPE values in the RAP of 3000-3500 J/kg just ahead of the MCS.
Deep layer shear of 40-50 kt will support supercells. In
addition, there will be strong divergence at the nose of a jet
streak to enhance lift, and strong frontogenetic forcing in the
925-700 mb layer. These factors point toward an enhanced large
hail and damaging wind threat. A tornado threat appears minimal
with the elevated nature of the convection. The threat will
exist across the entire area, but will be highest in the northern
Cumberland Plateau and KY border counties of SW VA as the models
suggest a weakening trend to the convection as it moves through.
The storms should be out of the area by 10Z.
The rain chance for Monday has trended downward, along with the
chance of strong/severe storms. With the upper trough still
overhead, some isolated to scattered showers will be possible,
mainly in the mountains. Most other areas appear to be under the
influence of a strong capping inversion around 800-850 mb that
will prevent vertical development in the afternoon. Will have low
to slight chance PoPs in eastern sections.
&&
.LONG TERM...
(Tuesday through next Sunday) Issued at 235 PM EDT Sun Jun 25
2023
Key Messages:
1. Mostly dry through the work week with temperatures trending to
above normal by late week. Cannot rule out the occasional
shower/storm at times.
2. Increasing chances of PoPs next weekend.
Discussion:
On Tuesday, upper level troughing will slowly meander ENE as ridging
gradually builds into the Great Lakes region throughout the week.
Increasing subsidence can be noted on GFS derived soundings around
800mb with an inversion associated with a layer of notably drier
air. This should act to keep much of the southern and central
portions of the area dry Tuesday. The chance of showers and storms
will still be possible in northeast Tennessee and southwest Virginia
in closer proximity to the trough axis.
As we head into the middle of the week, ridging impacts will
increase across the area. This will result in mostly dry days with
the occasional chance of diurnally driver pop-up shower or storm. It
continues to look like increasing H5 heights will lead to a warming
trend with above normal temperatures expected by late week.
Deterministic GFS and ECMWF show H85 temperatures in excess of 20C
by Friday afternoon. A stationary frontal boundary and potential
shortwave disturbances moving through mean flow aloft will bring a
return of PoPs this weekend. However, model discrepancies result in
minimal confidence and the inability to pick out much detail at this
time.
&&
.AVIATION...
(00Z TAFS)
Issued at 657 PM EDT Sun Jun 25 2023
Another round of showers/storms are expected to roll through
tonight, and will try to time these with categorical thunder along with
a 2 hour tempo group for stronger storms with very gusty winds
and lower conditions (MVFR/IFR). Outside of the storms, mainly VFR
conditions are expected.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 69 90 66 89 / 60 10 10 0
Knoxville McGhee Tyson Airport, TN 67 88 64 86 / 80 20 10 0
Oak Ridge, TN 67 88 63 86 / 80 10 0 10
Tri Cities Airport, TN 65 86 61 80 / 60 20 20 30
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...
AVIATION...
...Updated Aviation Forecast Discussion...
.UPDATE...
Issued at 608 PM CDT Sun Jun 25 2023
Geocolor satellite imagery is showing an area of surface smoke
coming south out of Canada along the Missouri River valley. Not
really seeing any significant surface visibility reductions
though, but it`s definitely noticeable/hazy when outside, and
could be sensitive for some folks. The HRRR and Rap smoke models
show this hanging around tonight, with an additional surge coming
southward tomorrow, and possibly even into Tuesday.
&&
.DISCUSSION...
Issued at 210 PM CDT Sun Jun 25 2023
Key Messages:
- Gusty winds diminishing this evening.
- Warmer temperatures with chances of storms mid-late week.
Now through Monday...
A vertically stacked low pressure system continued to churn through
Minnesota and Iowa today, inducing a tight pressure gradient across
eastern Nebraska and southwest Iowa. Northwest winds remained breezy
along that gradient, with multiple gusts up to 30-40 mph, a few even
inching towards 45 mph this afternoon. Winds will ease up through
the evening as high pressure seeps in at the surface, behind the
departing low. An upper ridge will build out of the Rockies and into
the Central Plains, maintaining dry conditions through tomorrow.
Noticeably cooler temperatures will continue to ride the
northwesterly flow, as afternoon temperatures are expected to top
out in the low to mid 80s today, and mid to upper 80s Monday.
Tuesday through Thursday...
A series of shortwaves will traverse the ridge over the coming week
giving us a few chances for spotty showers and storms Tuesday and
Wednesday. The best chance for widespread rainfall looks to be
Tuesday night into early Wednesday morning, based on current model
consensus. Temperatures will gradually warm through midweek,
reaching the upper 80s to mid 90s by Wednesday and Thursday.
Friday and Beyond...
A low pressure system traveling across southern Canada, towards the
Great Lakes, will shift the ridge to our east, as it drags a cold
front across the northern plains. Deterministic models indicate
strong to severe storms will be possible somewhere in the region
Friday evening/night, however the exact details, such as where and
when these storms will develop, remain uncertain at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 608 PM CDT Sun Jun 25 2023
Satellite imagery is showing a band of surface smoke that is
affecting the TAF locations, but no real significant reductions in
visibility. Smoke models suggest this may be in the area through
at least Monday, and possibly Tuesday. Otherwise, gusty northwest
winds will continue to diminish early in the TAF cycle, dropping
below 12 knots by 02z. Winds could increase to 12-18 knots at
KOMA/KLNK again by 26/15z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
UPDATE...DeWald
DISCUSSION...KG
AVIATION...DeWald
Area Forecast Discussion
National Weather Service Nashville TN
838 PM CDT Sun Jun 25 2023
...New UPDATE...
.UPDATE...
Issued at 838 PM CDT Sun Jun 25 2023
It`s been a quiet evening so far across Middle TN. We should see
that change as head into the late evening and early overnight. A
surface boundary is starting to push into KY stretching southwest
into AR. An MCS developed over AR and has pushed into western TN.
This MCS overall will miss our area but should clip our far
southern counties of Wayne, Lawrence, and Giles Counties. This
will bring a strong wind threat. Thunderstorms are expected to
fill in along the surface boundary over western and northern KY.
These storms will be the main threat for our area. They look to
push into northern areas after 10 PM and continue to push south
and east through the area. Surface dew points are in the mid to
upper 70s, CAPE values are up to 2000+ j/kg, and effective shear
of 40+ knots. This will support the potential for strong storms
with wind and hail the main threat. The low level jet will also
increase after 03z and that will bring increased low level
helicity and a chance for an isolated tornado or two. The line of
storms should clear our area by 4 am with much quieter and less
humid weather tomorrow.
&&
.SHORT TERM...
(This afternoon through Monday Night)
Issued at 129 PM CDT Sun Jun 25 2023
The severe weather threat we have been talking about over the last
several days is being realized this afternoon. A severe
thunderstorm watch for counties mainly south of I-40 and east of
I-65 is in effect until 6 PM. Radar is lit up with robust, tall
strong to severe thunderstorms that have a history of producing
large hail and gusty winds with very frequent lightning. This is
no surprise considering the amount of moisture and instability
that is out there. On the topic of moisture, dew points are well
into the 70s across all of Middle Tennessee. Couple that with the
high surface temperatures caused by a mass of warm air advection
and voila...you have heat index values soaring past 100 degrees.
This sparked a heat advisory for our 2 western rows of counties
that will be in effect until 7 pm.
One interesting note to add for those of you that like to look at
models is that the HRRR forecasted afternoon dew points to drop
into the low 60s which definitely did not happen. Because of
this, we recognized that convection was possible a lot sooner
than what the HRRR was showing, i.e. the current storms on radar.
We are still monitoring the potential for another round of severe
thunderstorms late tonight into the overnight hours as troughing
aloft will help push a weak front across the area. Though we are
experiencing storms now, instability values at the surface and the
mid-levels will still be plentiful enough to fuel storms and
produce large hail provided there is enough lift. From the
beginning, this complex of storms has been the most difficult to
forecast given the large amount of model uncertainty. Timing and
coverage have been the hardest to communicate because those
parameters are different on just about every model you look at.
The best way to handle the evolution of this is to simply say
this: anticipate severe storms from now through the overnight
hours. Again, healthy lapse rates with plenty of 0-6km shear and
large MLCAPE values will lead to storms capable of producing
damaging wind with large hail. The tornado threat remains low as helicity
values are less than 150 m2/s2.
If the storms tonight do not form a line like some model solutions
are showing, the more likely outcome will be widely scattered hit-
or-miss strong to severe thunderstorms; the kind where some may
not get anything at all. After whatever front moves through
overnight, our weather should be calm and hot for the remainder of
the week.
Monday is looking dry and mostly clear with highs in the low 90s
and lows in the upper 60s.
&&
.LONG TERM...
(Tuesday through next Sunday)
Issued at 129 PM CDT Sun Jun 25 2023
A large ridge responsible for the record-breaking heat in Texas
will slowly shift east and influence our weather for the remainder
of the week. Highs will steadily increase each day with a forecast
high of 100 degrees in Nashville by Thursday. Models are showing a
shortwave developing across the Great Plains that will bring our
next chance of rain by the weekend.
&&
.AVIATION...
(00Z TAFS)
Issued at 622 PM CDT Sun Jun 25 2023
A cold front is approaching Middle Tennessee from the west and is
producing ongoing convection as it pushes toward Middle Tennessee.
The HRRR brings a well-defined line of convection through the mid
state later this evening and overnight ahead of the boundary. Look
for rapid clearing behind the front with winds increasing tomorrow
and turning westerly.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 71 91 68 91 / 60 0 0 0
Clarksville 68 90 66 91 / 60 0 0 0
Crossville 65 83 61 81 / 80 10 0 0
Columbia 70 90 65 90 / 50 10 0 0
Cookeville 67 85 63 84 / 80 10 0 0
Jamestown 66 82 62 81 / 80 10 0 10
Lawrenceburg 68 89 64 89 / 60 10 0 0
Murfreesboro 69 90 65 90 / 60 0 0 0
Waverly 68 89 64 89 / 50 0 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Mueller
SHORT TERM...Baggett
LONG TERM....Baggett
AVIATION.....Rose
Area Forecast Discussion
National Weather Service Tucson AZ
208 PM MST Sun Jun 25 2023
.SYNOPSIS...Strong high pressure will start the new week with
the hottest temperatures of the year so far. A modest moisture
increase could bring a few thunderstorms close to the
international border this week. Breezy at times in the afternoon.
&&
.DISCUSSION...A strong ridge of high pressure across northern
Mexico extends into the Desert Southwest, with a high center
consolidating near far northwest Mexico over the next 24 hours.
This is pushing our temperatures up to around 10-12 degrees above
climo and should include the first 110 temperature for Tucson
Airport either today or Monday. Isolated near record highs with an
excessive heat warning for most lower elevation / valley
locations.
The tropics are now showing solid activity up to 15N with
increasing convection across southern to south central Mexico. In
addition, we`re still watching the deeper moisture intrusion along
the west coast that now includes southern Sonora in addition to
Sinaloa. HREF ensembles show a marked increase in the chance of 60
degree dewpoints and 1.2 to 1.5 inch precipitable water values
pushing into central Sonora over the next 48 hours, also reflected
by a narrow H7 theta-e ridge building up the Sierra Madres and
nosing into far SE AZ by Wednesday afternoon. Latest HRRR output
pushes outflow from northeast Sonora convection into Cochise
county Monday night. This isn`t a scenario that would start deep
widespread convection, but isolated thunderstorms near the border
are more and more likely this week even as broader monsoon support
remains well south.
In general, heights and thicknesses should support above to well
above average temperatures into at least next weekend.
&&
.AVIATION...valid through 27/00Z.
FEW-SCT clouds AOA 15k ft AGL southeast of a line from KOLS to KSAD,
with clear skies/SKC conditions elsewhere thru 26/05Z. Aft 26/05Z,
SCT-BKN clouds areawide AOA 15k ft AGL. WLY/NWLY SFC wind at 11-18
kts and gusts to 18-28 kts thru 26/02Z, and then developing again
aft 26/18Z. Between 26/02Z and 26/18Z, SFC wind less than 10 kts and
variable in direction. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...High temperatures will be above normal through the
work week with the hottest days expected to be Monday and Tuesday,
which will be 6-10 degrees above normal. Min RH values will be in
the 4-10 percent range in the lower elevations and between 10-18
percent in the mountains through much of this week, with a few
percent increase in RH values along the international border on
Wednesday and Thursday. 20-foot wind speeds will continue to remain
elevated through Wednesday at 10-20 mph during the afternoon and
early evening hours, especially across portions of Graham/Greenlee
counties. There will be a slight chance (10-15 percent) of mainly
dry thunderstorms across eastern Santa Cruz and the southern half
Cochise County each afternoon/early evening starting on Tuesday and
continuing through the upcoming weekend.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 11 AM Monday to 8 PM MST Tuesday for
AZZ503-504-506>509.
Excessive Heat Warning from 11 AM to 9 PM MST Monday for AZZ502-
515.
&&
$$
Meyer/Zell
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