Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/30/23
Area Forecast Discussion
National Weather Service Buffalo NY
1004 PM EDT Thu Jun 29 2023
.SYNOPSIS...
It will become warmer and noticeably more humid as we push into the
long holiday weekend...and unfortunately...this will include the
daily potential for showers and thunderstorms. While it will become
somewhat more unsettled...the vast majority of the Friday through
Tuesday time frame will be rain free.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
The last few frames of visible satellite continued to show
smoke across portions of western and north central NY this
evening. The window of less smoke across western NY with
visibility of greater than 6SM that was evident does seem to be
closing as the observation at KBUF is now back down to 5SM. This
seems to indicate that smoke across eastern Ohio is creeping
back into western NY. Pleasant weather will continue
tonight...as high pressure will exit across New England.
Temperatures will run close to normal across the western
counties...but will still average a few degrees shy of typical
late June values for the Eastern Lake Ontario region.
While the bulk of Friday will be rain free...the passage of a weak
warm front and corresponding mid level shortwave will support
scattered showers and thunderstorms. The system will also allow
warmer and more humid air to spread across our region...and this
will set the stage for uncomfortably high humidity levels for the
upcoming long holiday weekend.
Scattered showers and thunderstorms Friday evening will die off
during the course of the night...as the passage of a mid level
disturbance will help to shove a relatively deep plume of moisture
to central and eastern New York.
Apparent temperatures will climb to between 85 and 90 for Friday
afternoon.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A closed low just south of James Bay will move east across Quebec
while an area of enhanced westerly flow will move across the Ohio
Valley Saturday. Initially, showers will be diminishing and exiting
to the east Saturday morning. Muggy conditions expected Saturday
morning with dewpoints in the upper 60s. A cold front will approach
western and north central NY through the day. The moist airmass will
remain across the region with PWATS around 1.5 inches. Warm Saturday
with daytime highs reaching the mid to upper 80s. Diurnal showers
and thunderstorms will likely form by Saturday afternoon especially
along lake breeze boundaries and inland areas. The fast westerly
flow to the south may increase vertical shear profiles especially
across western NY into Saturday evening. This may result in a few
strong to severe thunderstorms. The "cold" front will move through
the region Saturday night, which will bring a little relief to the
humidity and a decrease in shower and thunderstorm activity. Low
temperatures will fall to the low to mid 60s.
Sunday will be another day of diurnal showers and thunderstorms,
however there will be more emphasis across western NY as a frontal
boundary lays near the New York and Pennsylvania border. This will
be a zone of convergence with more widespread showers and
thunderstorms and a potential of strong to severe storms, however
confidence is low if they will impact western NY. Cooler and dryer
air will filter into the North Country Sunday and while diurnal
showers and a few thunderstorms can`t be ruled out, coverage will
likely be lower than western NY. Highs will reach the upper 70s to
low 80s Sunday. Activity should diminish Sunday night with lows
reaching the 60s.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
Upper/mid- level trough overhead of much of the Northeast throughout
the first half of the week. A few hard to time shortwave troughs
will rotate through, and combined with the daily diurnal instability
trends along with mesoscale boundaries will support precipitation
chances Monday and Tuesday. Additionally temperatures will range in
the upper 70s and low 80s and conditions will be quite muggy.
Wednesday and Thursday, the upper level pattern will begin to shift
and supports an upper/mid- level ridge across the Great Lakes. With
the ridging aloft and associated subsidence, chances for showers and
thunderstorms will be lower than the days prior. Temperatures will
be warmer mid week with highs ranging in the 80s, warmer
temperatures occuring across the lake plains.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Smoke from wildfires continues to be the main story for the
terminals across western and north central NY through Friday.
There is a window of less smoke from KBUF to KJHW where
visibility is greater than 6SM. Satellite trends show the smoke
moving into KJHW however the HRRR smoke forecast has this
window persisting through tonight. Kept with current satellite
trends with visibility coming down across western NY. Other TAF
sites continue to produce visibility of 2-6SM. Conditions will
likely stay the same overnight and into Friday morning.
While mainly MVFR/VFR conditions will be in place across the
region on Friday...the passage of a warm front will offer the
potential for some showers and thunderstorms after 15z and
mainly across western NY.
Outlook...
Saturday through Monday...Mainly VFR with scattered showers and
thunderstorms.
Tuesday...Generally VFR but with the low chance for a shower.
&&
.MARINE...
Fair weather and light winds are expected on the lakes through
tonight as high pressure crosses the region.
A few rounds of showers and thunderstorms are expected starting
Friday and continuing into the weekend as an unsettled pattern
develops across the eastern Great Lakes. Locally choppy
conditions may develop in and around any thunderstorms.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...RSH
NEAR TERM...HSK/RSH
SHORT TERM...HSK
LONG TERM...EAJ
AVIATION...HSK/RSH
MARINE...Fries/RSH/TMA
Area Forecast Discussion
National Weather Service Cheyenne WY
526 PM MDT Thu Jun 29 2023
.UPDATE...
Issued at 100 PM MDT Thu Jun 29 2023
As of 19z, several trends in satellite and mesoscale observations
are becoming more clear as we head into yet another day of
thunderstorm activity in southeast Wyoming and western Nebraska.
The overall forecast highlighted in the early morning discussion
remains on-track. GOES visible satellite imagery depicts a few
areas of particular interest, the first of which is a pronounced
cumulus field in southeast Wyoming, from Laramie county stretching
north into the southern half of Platte and Goshen County. Surface
obs validate the moist southerly flow seen in cloud motion over
this region, with surface dewpoints generally in the mid-50s.
Along the northern periphery of this cumulus cloud feature,
surface flow and cumulus coverage appears to back westward a bit
as flow spills up and over the broad elevation gap in the central
Laramie range. To the west of this, a few high- based showers and
thunderstorms have developed in the Snowy Range foothills and are
drifting into the Laramie valley. A surface ob at KLAR of 78/48
with southeasterly winds gusting near 20 knots should be
sufficient to sustain convection across the Laramie Valley. As
thunderstorms interact with deeper moisture to the east, and
surface flow backs even farther near the terrain gap in the
Laramie Range, expect an intensifying trend to any dominant cells.
This is supported by most CAM guidance, with the HRRR once again
showing tremendous run-to-run consistency in one or two dominant
supercells developing near the Chugwater/Wheatland corridor and
moving east-southeast. Fast mid-level flow remains in place, and
favorable hodograph size and shape in the lower-levels is progged
through the mid and late afternoon hours. With time, convection
may encounter capping farther east in the Nebraska panhandle,
which may limit the eastward extent of the severe weather threat
today compared to past days. Additionally, boundary-layer flow is
much weaker farther east thus reducing hodograph shape which may
ultimately result in a less-discrete storm mode once storms enter
the Panhandle.
The second area of interest is farther north, over the northern
Laramie range where a severe thunderstorm has already developed
over the higher terrain. An agitated cumulus field is noted to the
east of this storm, with backed easterly flow up against the
mountains observed at several obs sites. Surface dewpoints are a
bit lower in this northern region, but the higher-elevation nature
of the storm and a bit better hodograph shape at this stage of
the afternoon will support a severe threat for several hours here
as well. Mesoanalysis indicates significant capping east of I-25
in the Glendo-Torrington area, supported by a more laminar,
matted appearance in visible satellite. If this capping can erode
and destabilize, any dominant storms that continue off the
northern Laramie range will pose a severe threat along and east of
I-25 through the afternoon as well.
Overall, large to very large hail remains the primary severe
weather threat given supercellular storm mode, large bulk shear
values, and a notable EML under deep surface moisture. A tornado
or two is also possible, especially as dominant cells mature and
interact with any lingering surface boundaries to the east. As
storm mode transitions to multicell/linear mode farther east, a
wind threat may develop. Finally, flash flooding remains a
possibility in any area that sees multiple rounds of convection.
&&
.SHORT TERM...(Today - Friday)
Issued at 355 AM MDT Thu Jun 29 2023
Prior Discussion remains on track for this afternoon. Second
paragraph discusses the Friday convective threat:
The potential for scattered to numerous showers & thunderstorms w/
continued threats for extremely large, destructive hail, localized
flash flooding, strong winds, as well as a few tornadoes continues
to be the primary focus over the next 24 to 36 hours. Thunderstorm
activity has remained fairly limited in coverage through the night
across southeast Wyoming and the western Nebraska Panhandle, which
will likely help keep thermodynamic profiles prime for yet another
day of strong to severe thunderstorms. Thunderstorm coverage could
be quite a bit higher today w/ much stronger forcing associated w/
a sharp upper-level trough poised to eject northeast across the 4-
Corners region by late morning and early afternoon. Also, we could
be looking at a much earlier start to convection w/ CI expected by
18z. Early-day surface heating coupled w/ ample low-level moisture
characterized by surface dew points in the low & middle 50s should
help support MLCAPEs of 1500+ J/kg in the presence of fairly steep
mid-level lapse rates near 8 deg C/km. 500-mb flow in excess of 50
knots, coupled with pronounced low-level veering should contribute
to 60+ knots of deep layer (0-6 km) vertical shear. Supercells are
expected in this environment w/ very large/destructive hail likely
to be the primary hazard, although line segments and some training
could also lead to periodic high winds and potential for localized
flash flooding. Forecast low-level hodographs are not particularly
impressive for this afternoon & evening, but given the presence of
pronounced low-level veering and very strong speed shear, isolated
tornadoes are certainly possible especially w/ any supercells that
can latch on to pre-existing boundaries. Like previous days, would
expect the tornado threat to be maximized near the Platte, Goshen,
Laramie tri-county region ( perhaps even slightly west into Albany
County today) into the southern Neb Panhandle including Cheyenne &
Kimball counties. This is where backed near-surface flow (courtesy
of the Chugwater Cyclone) will contribute to enhanced convergence,
as well as locally maximized effective bulk shear w/ effective SRH
near 150 m2/s2. High-res CAMs are in excellent agreement with very
intense & persistent UH tracks through these areas. Convection may
very well last well into the evening & perhaps overnight w/ likely
hazards transitioning more to small hail & flash flooding later in
the event.
The Friday forecast remains somewhat contingent on residual
overnight thunderstorm activity from today`s round. Earlier
short-term models suggested a mid-level vort max/MCV-type feature
drifting over east-southeast Wyoming through the day on Friday.
In more recent guidance, this feature is less apparent, suggesting
a more chaotic, disorganized multicell storm mode. Despite
residual surface moisture remaining in place on Friday (surface
Tds at or above 50 east of I-25), surface flow is progged to be
very meager, if not nill in most locations. Additionally, the
pronounced southwest flow aloft is progged to shift eastward into
the midwest, leaving flow of less than 25 knots in the mid-levels
over southeast Wyoming and western Nebraska. This combined will
reduce bulk shear values and greatly decrease hodograph size and
curvature, thus resulting in a more typical summertime pop-and-
drop convective mode compared to the discrete supercellular mode
seen in past days. Heavy rain will still remain a threat, with
plentiful moisture especially in the low-levels. Thus, the Flash
Flood Watch will remain in effect through Friday`s convection.
Expect thunderstorm activity to quickly diminish after sunset as
heights begin to rise and dry air pushes in from the west.
.LONG TERM...(Friday Night - Wednesday)
Issued at 355 AM MDT Thu Jun 29 2023
Prior forecast remains on track and the previously issued
discussion follows:
An unsettled long term pattern is expected with daily chances for
showers and thunderstorms across the region. A warming trend is
expected through Monday before temperatures start to cool again on
Tuesday. Severe weather is possible throughout the long term, but
details for any specific day are still uncertain at this time.
No major changes were made with this forecast package. As previously
mentioned, the general upper-level flow for this weekend through
early portions of next week is northwesterly flow aloft.
Northwesterly flow aloft provides a more favorable environment for
storms across the region as the several upper-level disturbances
traverse across the CWA. By Wednesday, an upper-level trough begins
to deepen over southern Canada and shift the upper-level flow to
westerly as zonal flow builds in behind the Canadian trough. A cold
front passes through the CWA on Tuesday, cooling temperatures for
the 4th of July holiday. The passage of the cold front on Tuesday
brings an increased threat for widespread showers and thunderstorms
for the holiday. Trends will need to continue to be monitored, as an
earlier frontal passage on Tuesday could retrain the amount of
showers and thunderstorms to the earlier hours of the day.
Severe weather is possible throughout the long term, as the CWA will
be in a favorable regime for severe storms. The specific details for
any day are uncertain at this point, but as of now the CWA is only
in a general thunder risk for Friday. Trends will continue to be
monitored, especially for the July 4th holiday as the synoptic
pattern looks more favorable for severe storms given the cold
frontal passage and favorable positioning of upper- and mid-level
jet streams on July 4th. However, as the previous forecaster
mentioned, 4th of July is still about a week away, so models could
change for the holiday!
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 514 PM MDT Thu Jun 29 2023
Mainly VFR conditions across southeast Wyoming and the Nebraska
panhandle with the exception of areas experiencing the line of
thunderstorms stretching from near KCDR to near KCYS and moving
eastward. Brief periods of MVFR to IFR conditions due to lowered
VIS and CIGS are possible over the next 2 to 3 hours at KCYS,
KBFF, KCDR, and KAIA. Areas of light fog are possible tonight
following the thunderstorms, but confidence is low in timing and
how widespread it will be. Additional thunderstorms tomorrow
afternoon beginning near 19Z.
&&
.FIRE WEATHER...
Issued at 1225 PM MDT Thu Jun 29 2023
Negligible fire weather threat in the short-term period as
abundant moisture from numerous thunderstorms keeps surface
moisture in place. As we transition into the weekend, expect a
drying trend with lower RH values and light westerly flow
returning. This may raise the fire weather threat by later in the
weekend and early next week.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Flood Watch through Friday afternoon for WYZ101-102-107-108-119.
NE...Flood Watch through Friday afternoon for NEZ002-003-019>021-054-
055-095-096.
&&
$$
UPDATE...MAC
SHORT TERM...CLH
LONG TERM...AM
AVIATION...LK
FIRE WEATHER...MAC
Area Forecast Discussion
National Weather Service Quad Cities IA IL
537 PM CDT Thu Jun 29 2023
...00Z AVIATION UPDATE...
.SHORT TERM...(This evening through Friday)
Issued at 236 PM CDT Thu Jun 29 2023
Key Messages:
1. Quiet night expected, with mild low temperatures.
2. Another active day is possible Friday, with a slight risk (level
2 of 5) of severe weather for southeast IA, northeast MO, and west
central IL. This is the same area that saw severe storms today.
Discussion:
An MCS tracked east near the IA/MO border today into a very moist
and unstable environment, bringing widespread damaging winds, at
least one tornado, torrential rain, and frequent lightning to
northeast MO and west central IL. Wind speeds in excess of 70 mph
were reported in Clark county MO and Hancock county IL. In addition,
rainfall amounts between 1-2 inches were reported in several areas
along and south of I-80, along with cooler temperatures. Lastly, the
strong winds aloft with this system has helped to mix out most of
the smoke that we have been dealing with for the past 3 days. Some
areas north of Hwy 30 still are reporting 1-3 mile vsbys from the
haze/smoke as of 2 pm. However, the latest run of the HRRR smoke
model continues to show an improvement this evening and overnight.
Tonight...increasing subsidence aloft and weak high pressure will
bring quiet conditions and calm winds. Overnight lows will only drop
into the upper 60s.
Friday...another strong wave will eject out into the Plains, with a
surface low developing in KS by 12z. A warm front will be draped
across northern MO through the day and will bring another round of
storms to areas that saw activity today. The latest 18z RAP shows
CAPE values over 2000 J/kg, PWATs over 1.7", and deep layer shear
values between 45-55 kts. These ingredients all suggest severe
weather will be possible and SPC has a slight risk (level 2 of 5) in
our far south for this reason. All hazards (damaging wind, large
hail, and a few tornadoes) will be possible. The one thing that I
have seen that is different for this event than compared to today
are the mid level lapse rates are somewhat lower (6-7C/km) and the
mid level wave position is slightly further north. This just means
that the confidence in severe weather placement and strength
is lower. The latest CAMS/HREF progs suggest this activity will
occur in the 12z to 20z window, which is the same as today. Left
forecast highs in the mid to upper 80s alone for now, but these
could be too high depending on cloud cover and anticipated storms.
.LONG TERM...(Friday night through Thursday)
Issued at 236 PM CDT Thu Jun 29 2023
Key Messages:
1. Active weather pattern continues through the weekend, with
several chances of showers and thunderstorms and some much needed
rainfall. Latest drought monitor released today showed an increase
in severe drought conditions.
2. Warm and mostly dry weather expected early next week for the
3rd and 4th of July.
Discussion:
A positively tilted longwave trough will track over the Great Plains
into Iowa this weekend. Large scale ascent with this wave in a very
moist and high theta-e environment, will bring several rounds of
showers and thunderstorms to the region. While there is still a
lot of differences in projected totals, model ensembles and the
NBM all support much of the area receiving at least an inch of
rain this weekend. NBM probs (50-70%) of 1+ inch of rain are
highest along and south of highway 30. This is good news to
drought stricken areas, which has continued to worsen in recent
weeks. For those with holiday weekend activities, not all of the
weekend will be wet. The highest chances of rain (50-75%) at this
time will be in the Saturday afternoon-Sunday morning time frame.
Extensive cloud cover and rain will keep highs cooler this
weekend, with readings in the low to mid 80s.
Early Next Week...building heights aloft and weak high pressure will
bring warm and mostly dry conditions to the area. This will be ideal
for holiday festivities, with highs in the upper 80s/low 90s and
lows in the low to mid 60s. Dewpoints are expected to remain in the
60s, making it feel not too humid.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 524 PM CDT Thu Jun 29 2023
IFR to MVFR visibilities in smoke may linger or develop with light
winds. In addition, some fog is also possible later tonight with
IFR to MVFR visibility restrictions pending cloud cover. Shower
and storm chances will increase Friday AM as the next disturbance
approaches. Best chances are favoring BRL after 12z to 18z where
TEMPO mention was included and will have PROB30 mention at CID and
MLI. Gusty winds and hail will be possible with the strongest activity.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SHORT TERM...Gross
LONG TERM...Gross
AVIATION...McClure
Area Forecast Discussion
National Weather Service Louisville KY
953 PM EDT Thu Jun 29 2023
.Forecast Update...
Issued at 950 PM EDT Thu Jun 29 2023
Currently, radar shows a stronger storm over Grayson County, KY.
Upstream in southwestern Indiana, there are a few more strong storms
that will continue to move eastward. The environment as the storms
move east is less favorable for development and maintenance, so they
are likely to dissipate as they move eastward.
The HRRR has been doing well today with the multiple rounds of
storms that have moved through the area. Models suggest another
round of scattered showers and storms to develop in the early
morning hours around 04-05Z. These storms would develop over
southern Indiana and move southward exiting the region around 12Z.
With the rounds of showers and storms, the smoke has been moved out
of the region and visibilities have been restored.
&&
.Short Term...(This evening through Friday)
Issued at 308 PM EDT Thu Jun 29 2023
Latest surface analysis reveals a serpentine warm front extending
from low pressure centered over the IA/MO/IL border and winding
southward along the MS River while sprawling high pressure extends
across the East Coast. Current radar shows this morning`s convective
complex exiting to our south into central TN as widespread rain
slowly drifts south through south-central KY. Also evident and more
concerning is a N-S oriented line of storms pushing through central
IL, which will affect our CWA later this afternoon/early
evening...more on this below.
The above mentioned line of storms has developed on the nose of an
80kt 5H jet max, which continues to push ESE into Indiana. As the
line pushes east into Indiana, uncertainty remains in the overall
track. Latest SPC Mesoanalysis shows a much more favorable
thermodynamic environment across northern Indiana and southward
towards Paducah, with a more stable environment across our southern
Indiana and central KY counties due to earlier convection. In fact,
KY Mesonet shows current temperatures across central KY in the low
70s. Due to the uncertainties with the evolution of the line of
storms, a Severe Thunderstorm Watch has been issued the includes a
portion of our southern Indiana counties including Dubois, Perry,
Crawford, Orange, and Washington. If the line maintains strength,
damaging winds would be the primary hazard of concern with hail and
a small tornadic threat as well. Again, confidence remains low with
regards to exact strength of the system, so please stay informed to
your local weather.
CAMs have struggled with today`s convection and are currently
struggling to initialize well with the location of the line of
storms in IL, but there is general agreement in scattered convection
overnight into the early morning hours of Friday.
Synoptically, little change will take place tomorrow as upper level
ridging remains in tact over ArkLaTex with troughing in Canada north
of the Great Lakes. 5H convergence will once again see an uptick in
winds aloft, which will likely result in another round of
afternoon/evening convection for the region.
Heat Advisory is still in play for tomorrow as high temperatures are
projected to climb into the low 90s east of I-65 and into the mid
90s west of I-65. With surface dew points remaining in the 70s, heat
indices could exceed 105F for areas west of I-65.
.Long Term...(Friday night through Thursday)
Issued at 230 PM EDT Thu Jun 29 203
Wet pattern, with some strong to severe storms, looks to persist
into the weekend. A ridge across the Deep South will get slowly
pushed southward this weekend, as a trough moves into the Midwest.
Small disturbances riding across the quasi-zonal flow in between the
two will mean additional waves of storms pushing west to east across
the region. This pattern is difficult to peg the exact timing of
best storm development as well as location, but we can have some
confidence in probabilities of precipitation. Depending on timing
during the peak heating can lead to severe weather too. Temperature
forecasts are very tricky here, as more of a gap in the rains during
the daytime will means highs reaching well into the 90s, with our
southwest having chances to reach Heat Advisory or perhaps Excessive
Heat Criteria. This call will have to be made likely the day of.
The best chance for widespread rainfall looks to be Sunday, ahead of
that upper low moving in from the Midwest. Coverage should be
widespread enough to limit severe weather, but again some of this
depends on how the previous waves of storms push thru Fri/Sat.
As we get to Mon-Thu the flow aloft will become somewhat light and
convection should be more pulse in nature. Temperatures look to be
more summer like in that period given some better chances for
sunshine each daytime period.
One last thing to note, despite being abnormally dry for a bit, the
latest drought monitor this morning came in with some improvement
over the region. The rainfall we had west of I-65 earlier today and
these next few waves coming in could bring up the risk for flash
flooding. It will depend on training of storms and which locations
receive several rounds of storms the rest of today through
Sunday...so stay tuned for updates.
&&
.Aviation...(00Z TAF Issuance)
Issued at 730 PM EDT Thu Jun 29 2023
Discussion:
Current radar shows a line of showers over Central Kentucky. This
line consists of remnants from the earlier line that moved in from
southwestern Indiana. The showers will continue to propagate
eastward and dissipate over time. There is new robust convection
which formed in southwestern Indiana that is moving into the region.
It should be to HNB around 0Z. The environment southeast of HNB is
not as conducive for convection, so this will dissipate as it moves
eastward.
Overnight, showers and storms will form and move southeast over the
region. Being in a pattern as this, leaves more uncertainty in
forecast timing.
Tomorrow, we should remain mostly dry and hot under the upper-level
ridging.
Additionally, the rain today has most likely pushed the smoke out of
the region that has blanketed the region for the past few days. The
expectation is that visibilities will be better overnight because of
this.
Confidence:
Medium-high confidence on the occurrence of showers and storms
overnight, but confidence is low on timing and exact location.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...SRM
Short Term...CG
Long Term...RJS
Aviation...SRM
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
839 PM EDT Thu Jun 29 2023
.SYNOPSIS...
Brief high pressure will build over the region through this evening
as upper level troughing progresses east into New England. Dry and
hazy conditions will continue as a result with additional Canadian
wildfire smoke filtering in. Winds switch to the south Friday
pushing the smoke out of the region with shower and thunderstorm
chances returning Friday afternoon. These chances will continue
throughout the weekend into early next week as an area of low
pressure and its associated cold front approach the region. The
front stalls nearby Monday before clearing the area midweek.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Dry and hazy conditions continue this evening with high
pressure briefly building overhead. Northwest flow aloft
continues to steer smoke from eastern Canadian wildfires into
the region. Code Red Air Quality Alerts continue as a result
for all of Maryland, northern Virginia, much of the Shenandoah
Valley, and the eastern panhandle of West Virginia. Meanwhile,
the upper-level trough to our north and east continues to
progress east of New England, with the northeast extent of the
upper-level ridge building into western sections of the
forecast area. Any smoke and haze likely becomes trapped
overhead as particulates become trapped beneath a strengthening
nocturnal inversion. Additionally, expect a gradual uptick in
moisture at the surface yielding dewpoints back in the 60s/70s
over the next 24 to 36 hours.
High cloud cover will work back into the region overnight. Eyes
turn to the north and west as areas of positive vorticity
advection shift southeast from the Ohio River Valley. This will
steer multiple MCSs through the Midwest and into the Ohio River
Valley/central Appalachians region. CAMS/obs/trends continue to
suggest that this activity will stay south and west of our
region into southeastern Ohio and southern WV through early
Friday morning with maybe a few showers and perhaps a
thunderstorm grazing the VA/WV Highlands late. Overnight lows
will fall into the low to mid 60s west of the Blue Ridge
Mountains, with values closer to 70 in the urban corridor. If
we receive more cloud cover earlier, lows could be a little
warmer.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Shower and thunderstorm chances increase into the weekend as a warm
front approaches from the south. Brief high pressure will
continue east Friday allowing warm/moist southerly advection to
funnel in. Some smoke/haze will remain during the first half of
the day, although air quality will gradually improve due in
part to a change in wind direction. With the low-level wind
shift, expect building mid-level heights as the stout upper-
level ridge over the Gulf Coast nudges north and east over the
region. This will yield much warmer temperatures Friday into the
weekend while acting as a catalyst for increased shower and
thunderstorm activity from multiple waves of energy pushing
through.
12z CAM guidance suggests multiple convective waves tracking
through Friday into Saturday. The first wave (per the HRRR and
HREF) looks to slide south of the region Friday morning, with
its residual outflows firing convection mainly west of US-15
Friday afternoon into Friday evening. A secondary wave of energy
looks to impact the area Saturday as a warm front lifts into
the region. Convective coverage combined with the severe threat
appears to be higher with confidence increasing between model
runs. For now, went with an uptick of shower and thunderstorm
activity west of US-15 Friday afternoon into Friday evening.
Coverage will be scattered in these areas and relatively
isolated further east into the urban corridor due to residual
dry air from the ridge aloft. Instability values run between
1000-2000 J/kg with vertical effective shear averaging between
15 and 20 knots in these aforementioned locations. Currently,
the Storm Prediction Center has painted a Marginal risk for
severe thunderstorms, mainly west of US-15 Friday, with wind
and hail as the primary threats.
By Saturday morning, the warm front should cross the region.
Moist/warm advection will continue to increase along with
instability during the afternoon and evening hours. This will yield
a typical summertime regime of diurnally driven showers and
thunderstorms. The focus Saturday will be along the front as
well as across the high terrain, and potentially the bay/tidal
Potomac due to the bay/river breeze. CAPE values will remain on
the order of 1000-2500 J/kg with shear values around 30 kts.
This will lead to a bit more organization with storms Saturday
afternoon.
Temperatures will be at or above average with muggy dewpoints
areawide. Highs in the 80s, with a few spots going into the 90s east
of the Blue Ridge and along the I-95 corridor are expected.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Starting off the long term period on Sunday, ridging will be in
place across the southeast US, while an elongated northeast to
southwest oriented zone of troughing will reside from Quebec and
Ontario, across the Great Lakes, and toward the central Mississippi
Valley. This zone of troughing will feature two more compact
embedded shortwaves, with one located across southern
Quebec/Ontario, and another further southwest across the central
Mississippi Valley. Moving through the day Sunday, the northern
shortwave will progress eastward across Quebec, while the southern
shortwave starts to shear out a bit and become more elongated in the
southwest to northeast direction as it tracks into the Great
Lakes/Ohio Valley. This trough will slowly translate eastward on
Monday, with the base of the trough tracking into Ohio and western
Pennsylvania.
As this trough tracks to our northwest, south to southwesterly
return flow will develop in response, drawing very warm and humid
air into the region. Highs on both Sunday and Monday are expected to
reach into the upper 80s and low 90s, with dewpoints climbing into
the lower to middle 70s. Winds in the mid-upper levels of the
atmosphere will also be on the increase as the trough approaches the
area. Our positioning downstream of the approaching trough will also
place us in a favorable location for weak synoptic scale forcing
for ascent. As a result, thunderstorms are expected to form
across the area on both Sunday and Monday afternoons. With
winds on the increase aloft, and increasing low-level moisture
being drawn northward into the region, it appears as though this
system may create a favorable overlap of moderate to high
instability and appreciable wind shear, making strong to severe
thunderstorms possible. Most model guidance shows around 30-40
knots of 0-6 km shear both days, which would be enough to get
organized storms on its own. What`s particularly eye-catching
though is that most of the shear occurs in the 0-3 km layer,
with models showing 30-40 knots of flow at 700 hPa, which is
highly atypical for early July (above the 90th percentile, and
nearing daily maxes for the IAD sounding site according to the
SPC sounding climatology site). Severe thunderstorm potential
will be dependent on a number of factors, including convection
from preceding days, as well as how the large scale pattern
evolves. Given that it`s 4-5 days out, a lot can change, but
we`ll continue to monitor the potential for strong storms Sunday
and Monday over the upcoming days.
The aforementioned trough will continue to progress eastward on
Tuesday and Wednesday. This may allow for a greater northerly
component to the low-level flow on Tuesday, and a resultant slight
drop in dewpoints. While a stray shower or thunderstorm can`t be
ruled out, the trough progressing to our east and a slight decrease
in low-level moisture looks to make conditions a bit less favorable
for widespread thunderstorms. Mid-level ridging will start to build
overhead on Wednesday, making conditions a bit less favorable still.
But as is often the case during the summer, a stray afternoon
thunderstorm can`t be ruled out with the heat and humidity in place.
Although dewpoints may be a few degrees lower (upper 60s),
temperatures will continue to top out in the upper 80s and low
90s.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Haze and smoke look to remain the primary issue to aviation
tonight. Vsbys continue to hover between IFR to MVFR at all TAF
sites due to FU/HZ. Vsbys are expected to continue to hover
between 2-5SM with SCT-BKN cigs between 030-060 through the
night as particulates become trapped under a strengthening
nocturnal inversion. Otherwise, dry conditions will continue
with high pressure drifting by. Expect clouds increasing from
the west Friday morning before a slow spread east as return flow
ensues across the region and a storm complex dies to the south.
This complex of storms will put off outflow boundaries that
will be the focus for diurnally and terrain driven convection in
areas near and west of KMRB/KCHO Friday afternoon. For now,
went with a mention of VCTS at these terminals with lower
confidence further east. Daily shower and thunderstorm chances
increase into the weekend given moist southerly flow and upper
disturbances tracking in from the west. As a result, expect
brief restrictions each afternoon and evening as these storms
move through. There is plenty of model variability in timing and
placement of these features. Thus, will continue to favor the
typical favored times of day for Mid-Atlantic warm season
convection.
Winds Friday will switch to the south and southeast with gusts up to
15 kts Friday afternoon and evening. Similar winds expected on
Saturday and Sunday with a warm front nearby. Winds in and around
thunderstorms would be stronger and more chaotic in nature.
Mainly VFR conditions are expected for the end of the weekend
and into Monday with occasional drops in conditions with any
passing thunderstorms over the terminals in the afternoon and
evening. Winds will continue to blow out of the S/SW during
this period, as well.
&&
.MARINE...
Sub-SCA level winds will continue through Friday morning with
light and variable winds as high pressure briefly builds into
the region. Eventually, high pressure moves offshore yielding a
pronounced period of southerly flow. Models continue to show an
uptick in these winds Friday afternoon into early Friday night.
Some southerly channeling of these winds along the Chesapeake
Bay may lead to 18 to 20 knot gusts. Small Craft Advisories have
been issued for the 18z to 03z period to cover this threat.
Winds do become a bit lighter into Saturday. With convective
chances returning on Friday and Saturday, thunderstorms may
impact the waterways leading to hazardous conditions.
Sub-SCA winds are expected Sunday into Monday. Special Marine
Warnings may be needed both afternoons and evenings with any
strong thunderstorms that cross the waters.
&&
.TIDES/COASTAL FLOODING...
Tidal anomalies are expected to hold relatively steady tonight, with
some of the more sensitive sites entering action stage. Winds will
turn southerly tomorrow, allowing anomalies to start rising. As a
result, more sensitive locations like Annapolis may reach minor
flood stage with the tide cycle tomorrow night, and other sites like
DC SW Waterfront, Straits Point, and possibly Baltimore are likely
to enter action stage, and may approach minor flood stage.
&&
.EQUIPMENT...
KLWX is in the final stage of an important upgrade. Technicians
will refurbish and replace the pedestal, one of the most
critical components of the radar, which is necessary for antenna
rotation and positioning to capture data in all directions. The
components are extremely heavy and will require the radome to
be removed by crane and replaced when the work is completed.
Estimated full return to service is still June 30th, barring
any unexpected issues.
During the downtime, adjacent radars will be available,
including: Wakefield, VA (KAKQ), Roanoke, VA (KFCX), Dover, DE
(KDOX), Charleston, WV (KRLX), Pittsburgh, PA (KPBZ), State
College, PA (KCCX), and Fort Dix, NJ (KDIX)...also FAA Terminal
Doppler radars for Dulles (TIAD), Reagan National (TDCA),
Thurgood Marshall BWI (TBWI), and Joint Base Andrews (TADW). For
direct access to any of these surrounding radar sites, visit
the following Web page: https:/radar.weather.gov/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 2 PM to 11 PM EDT Friday for
ANZ530>534-537>543.
&&
$$
SYNOPSIS...EST
NEAR TERM...DHOF/EST
SHORT TERM...BRO/EST
LONG TERM...KJP/ADM
AVIATION...DHOF/ADM/EST
MARINE...ADM/EST
TIDES/COASTAL FLOODING...LWX
EQUIPMENT...LWX
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 257 PM CDT Thu Jun 29 2023
Key Messages:
- Another thunderstorm complex will move through the area late
tonight into Friday morning with a risk for severe weather and
localized flooding.
- Storm chances remain in the forecast Friday into Saturday
night. Some flooding and/or severe weather is possible.
- Dry and warmer Sunday into Tuesday.
Tonight into Friday morning:
Satellite-derived total precipitable water and early afternoon
surface observations indicate a w-e-oriented axis of richer
tropospheric moisture situated along the NE-KS border, along and
just to the north of the outflow boundary remnant from this
morning`s MCS. That moisture axis is likely to drift north tonight
in response to the development of a 20-30 kt low-level jet over
KS, supporting air mass destabilization, at least across the
southern half of our area. Meanwhile, thunderstorms currently
developing over southeast WY are forecast to grow upscale into an
MCS over portions of western into central NE this evening into
tonight, aided by the interaction between amalgamating cold cools
and the unstable downstream air mass.
Latest CAM output offers various degrees of MCS organization and
latitudinal variance in location by the time the convective
system reaches our area after midnight. The past few runs of the
HRRR have trended south with the most intense convection
overnight; in line with the 12z runs of the NSSL-WRF and NAMnest.
Given the current location of better moisture/instability
(as mentioned above), we are leaning toward the more southern
solutions. Accordingly, the greatest severe weather and heavy
rainfall potential appears to be along and south of the Platte
River and I-80. In other words, we could see a scenario similar to
that which unfolded this morning. Damaging winds of 60-70 mph
appear to be the primary hazard, though hail up to 1" and
localized flash flooding are also possible. Storms are expected to
exit our area between 7 and 8 AM Friday.
Friday afternoon and Friday night:
A midlevel trough currently over the Interior West is forecast to
shift east into the northern and central Plains with showers and
thunderstorms possible from Friday afternoon through Friday night.
Model forecast soundings suggest that both shear and instability
will be on the margins of that which supports organized storm
modes. Nonetheless, isolated occurrences of hail and/or strong
wind gusts cannot be ruled out.
Highs Friday will be mainly in the 80s.
Saturday and Saturday night:
The above-mentioned, midlevel trough will continue east/southeast
through the mid/lower-MO Valley with showers and thunderstorms
appearing likely during the day, especially for locations south of
I-80. Since sequential rainfall events will have likely occurred
south of I-80 prior to Saturday morning, there could be an
increased potential for flash flooding, as highlighted by the WPC
Day 3 excessive rainfall outlook.
Clouds and precipitation will likely to hold temperatures in the
70s to low 80s Saturday.
Sunday through Wednesday:
Midlevel heights will rebound Sunday in the wake of the shortwave
trough passing to the east, and ahead of a strong low pressure
system moving from western into central Canada. The Canadian
system will eventually drive a surface cold front into our area by
about Tuesday with the chance of rain increasing Tuesday night
into Wednesday.
Daytime temperatures are expected to warm from Sunday (highs in
the 80s) to Tuesday (highs in the upper 80s to mid 90s), ahead of
the approaching cold front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 634 PM CDT Thu Jun 29 2023
Expect another round of strong thunderstorms early Friday morning,
though latest guidance suggests winds will not be as strong as
they were this morning. Currently still some questions on exact
timing and duration at any given TAF site, but consensus favors a
relatively longer duration with repeated rounds of storms over
3-4 hours. A few showers may linger into Friday afternoon, but not
expecting any impacts from those. Outside of storms, expect VFR
conditions with mid to high clouds this evening and 8000-9000 ft
clouds behind the storms on Friday.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Mead
AVIATION...CA
Area Forecast Discussion
National Weather Service Nashville TN
858 PM CDT Thu Jun 29 2023
...New UPDATE...
.UPDATE...
Issued at 853 PM CDT Thu Jun 29 2023
Earlier convection has almost entirely dissipated over Middle
Tennessee and the HRRR shows very little additional activity until
after 10Z when MCS remnants are expected to enter the Upper
Plateau. The evening sounding from OHX shows modest levels of
instability even though we were sampling a post-storm environment.
However, a rather pronounced inversion below ~875 mb appears to be
keeping a lid on things in the near term. Have already made minor
adjustments to evening POP`s. No further changes are planned.
&&
.SHORT TERM...
(This afternoon through Friday Night)
Issued at 204 PM CDT Thu Jun 29 2023
Per current convection and latest CAMs, looks like mid state will
not get as much temperature recovery as previously anticipated
later today, and thus cancelled heat advisory. Will continue with
excessive heat warning for Friday. Not great consensus in model
specifics, so went close to previous forecast and previous
forecast reasoning through Friday night. It is very hard unless
you have a real dry airmass in place to reach century mark or go
above it for the Nashville area. With scattered showers and
thunderstorms possible Friday afternoon, have lowered temperatures
a few degrees but unseasonably hot conditions expected no matter
what as apex of upper ridging influences build across our area.
Will keep lows tonight and Friday night seasonably mild.
&&
.LONG TERM...
(Saturday through next Thursday)
Issued at 204 PM CDT Thu Jun 29 2023
Another heat advisory or excessive heat warning could be issued
for Saturday, but need at least an additional model run suite for
better clarity for issuance. Look for an unsettled summertime weather
pattern to rule through next Thursday. A surface front meandering
across our area on Tuesday will also aid in convection development
potential. Temperatures will remain a few degrees above seasonal
normal values through next Thursday also.
&&
.AVIATION...
(00Z TAFS)
Issued at 628 PM CDT Thu Jun 29 2023
Outflow boundary moved through several terminals with gusts north
of 30 kts around 2315Z, but has moved south now.
Mostly VFR conditions are expected for this TAF cycle, however
some storms are possible around sunrise for CSV/SRB. These could
cause a reduction to IFR for a few hours.
Winds will mainly be light with a westerly fetch on Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 75 99 76 98 / 20 40 20 50
Clarksville 73 99 73 97 / 20 30 30 50
Crossville 65 89 68 89 / 40 40 40 50
Columbia 72 99 72 98 / 20 30 20 50
Cookeville 67 93 68 92 / 30 40 40 50
Jamestown 66 88 67 89 / 50 40 40 50
Lawrenceburg 71 98 71 97 / 20 30 20 50
Murfreesboro 71 99 72 98 / 20 40 30 50
Waverly 72 99 71 97 / 20 30 30 50
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 11 AM to 8 PM CDT Friday for Bedford-
Cannon-Cheatham-Clay-Coffee-Davidson-De Kalb-Dickson-Giles-
Grundy-Hickman-Houston-Humphreys-Jackson-Lawrence-Lewis-Macon-
Marshall-Maury-Montgomery-Overton-Perry-Pickett-Putnam-Robertson-
Rutherford-Smith-Stewart-Sumner-Trousdale-Van Buren-Warren-Wayne-
White-Williamson-Wilson.
&&
$$
UPDATE.......Rose
SHORT TERM...JB Wright
LONG TERM....JB Wright
AVIATION.....Unger
Area Forecast Discussion
National Weather Service New York NY
1130 PM EDT Thu Jun 29 2023
.SYNOPSIS...
Weak high pressure passing overhead tonight will pass offshore
on Friday. A warm front will approach late Friday before
stalling and weakening nearby Friday night into Saturday. The
front will then lift through Saturday night, but then stall
again nearby from Sunday through the middle of next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
Subtle height rises take place tonight, with the more noticeable
height rises at 700 mb into Friday. Enough capping will remain
in place between 5 and 10 kft to preclude any precip chances
for tonight and through the day on Friday. Later in the
afternoon on Friday a warm front begins to approach from the
west. This will usher in more in the way of mid level clouds
late Friday afternoon into Friday evening. Previous HREF
guidance indicated a slug of higher PoP associated with showers
and thunderstorms into east central PA by late Friday/Friday
evening. The newer HREF and HRRR guidance, along with the RGEM
guidance, are less aggressive, and lead to further evidence of
dry conditions continuing through all of Friday evening.
The main question for the period is how much haze and smoke gets
back into the area and how far east does it reach. There
remains a lot of uncertainty with regard to visibility and the
precise air quality impacts from smoke and haze associated with
the Canadian wildfires and its associated smoke plume. For now
have settled in with mainly 5-7 statute mile visibilities, but
3-4 statute mile visibilities at shorter durations are likely to
take place for western portions of the CWA, including NYC.
Temperatures are expected to average at near normal levels into
Friday, with mostly clear skies. Mostly sunny conditions are
anticipated Fri morning, although haze will be prevalent,
followed by more in the way of mid level moisture and clouds
later in the day on Friday.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
The newer HREF guidance along with the 12z Thu guidance of the
higher res Canadian and other CAM guidance has it remaining
primarily dry through Friday night. The cap however weakens during
Friday evening. With a warm front going through frontolysis /
weakening it is questionable as to how far east any shower activity
can get. It seems prudent to have a slight chance of showers for at
least a portion of the area Friday night as the warmer and more
humid air mass begins to gradually begins to work in from the west
along with a light onshore flow at and near the sfc out of the SE
take shape. Therefore have gone only with slight chance PoPs for the
western periphery of the CWA (mainly W Orange County) for most of
Friday night. Introduce slight chance PoPs further east closer to
day break on Saturday with some light showers potentially coming in
out of the south off the ocean on a light onshore flow. Temperatures
will not move much Fri night with lows in the 60s, with middle and
upper 60s for the metro areas.
Saturday will feature the more humid airmass getting more of a grip
on the area as sfc dewpoints get into the middle and upper 60s. What
is left of a warm front will stall nearby. The GFS and Hi-Res
FV3 increase PW to about 1.5 inches by afternoon, with the
NAM-3km delaying arrival of the higher water content relatively
speaking. BUFKIT forecast soundings indicate a good deal of mid
level moisture, with the sfc to 5 kft layer being relatively
drier, especially for eastern portions of the CWA. Slight chance
to chance showers seems prudent for the time being for daytime
Sat. Kept thunder chances minimal as the instability remains
back to the west for the first half of the weekend with the area
not yet in the warm sector.
Temperatures will be a few degrees warmer Fri night, and perhaps a
few degrees cooler on Saturday due to more in the way of clouds.
Temperatures overall will be right around the seasonable norms.
With regard to the smoke and haze, after consultation with the
NYS DEC and inspection of the HRRR, the Canadian RAQDPS, and
the experimental RRFS there remains some question as to how long
the plume lingers across a good portion of the CWA. At this
time for Fri night it appears that the higher concentrations of
haze and smoke may begin to dissipate and start to lift further
north, with the higher probability of this taking place for Sat.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
After the passage of a cold front on Saturday, a warm front will
bring increasing moisture and lift Saturday night The warm front
then begins to pass through the forecast area Saturday night. Rain
chances will continue until Monday morning with the passage of the
warm front. Slight chance of thunderstorms early in the night.
An unsettled period is expected in the long term as a weak frontal
system lingers over the area. Based on the 12Z GFS a plume of high
moisture air consisting of 2-2.25 inch PWAT values will move into
the area Sunday. These PWATs are above the max moving average for
this time of year per SPC`s Sounding Climatology Page. This has been
consistent in the last several model runs. Elevated PWATs just under
2 inches (reaching about 2 inches, at times) sticks around through
Tuesday. After mainly zonal flow aloft on Sunday, a trough will
approach and be slow to pass to our east. This set up will likely
result in showers and thunderstorms each day. At this time,
widespread hydrologic impacts are not expected. WPC has
outlined the whole CWA in a marginal risk in their Day 4
excessive rainfall outlook, with only portions of northeast NJ
and the Lower Hudson Valley included in a marginal risk for Day
5. Additionally, the experimental CSU machine learning severe
weather forecasts have our area in a marginal risk of severe
weather each day in the forecast, mostly from daily diurnal
convection.
Temperatures will run right about average, with highs in the 80s
each day and a slight warming trend. Given the high moisture and
lack of clear nights, lows will be well above average, in the
upper 60s to lower 70s.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
Weak high pressure passing overhead tonight will pass offshore
on Friday.
Still seeing MVFR vsby in haze/smoke at KSWF/KHPN, and it should
make a return during the daylight hrs, affecting all the NYC
metros and points north/west. Sea breezes should lead to late
day improvement.
Winds tonight become light and variable, then the synoptic flow
becomes S 5-10 kt daytime Fri.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Sound breeze may prevent MVFR vsby from directly affecting KLGA
though there will still be haze aloft. Otherwise, unscheduled
AMD not expected unless MVFR vsby in haze develops sooner than
fcst.
OUTLOOK FOR 00Z SATURDAY THROUGH MONDAY...
Friday night: Chance of showers/MVFR cond, with possibly a tstm
at KSWF.
Saturday and Sunday: Showers likely and chance of tstms, mainly
each afternoon/evening. MVFR expected, IFR possible with this
activity.
Monday and Tuesday: MVFR possible. Chance of mainly
afternoon/evening showers/tstms.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
No advisories are expected for the coastal waters on a light
S-SE flow to round out the week. Ocean seas subside closer to 3
ft Fri into Fri night. The S to SE flow then may increase
somewhat to begin the weekend with ocean seas getting closer
to 4 ft by early Sat evening.
Sub-advisory conditions are expected to prevail Saturday through
Wednesday with a weak pressure gradient in place and a lack of
significant swell. However, there will be a slight chance to
chance of thunderstorms each day, which could result in locally
hazardous conditions.
&&
.HYDROLOGY...
At this time there are no anticipated hydrologic impacts through
Wednesday. Localized impacts may become possible toward Sunday,
and it is still too early to pinpoint the details.
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip current development expected for Friday
and Saturday on the ocean waters.
With astronomical tides increasing this weekend as we head
toward a full moon on Monday, minor coastal flooding may be
possible with the evening high tide cycles from Saturday
through at least Monday. Areas most likely to be affected are
the south shore bays of Nassau, Queens and Brooklyn, Staten
Island, and Southern Fairfield/Westchester Counties.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT Friday for CTZ005>012.
NY...Air Quality Alert until midnight EDT Friday night for
NYZ067>075-078>081-176>179.
NJ...Air Quality Alert until midnight EDT tonight for NJZ002-004-
006-103>108.
MARINE...None.
&&
$$
SYNOPSIS...JE/BR
NEAR TERM...JE/BR
SHORT TERM...JE
LONG TERM...BR
AVIATION...BG
MARINE...JE/BR
HYDROLOGY...JE/BR
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Raleigh NC
1000 PM EDT Thu Jun 29 2023
.SYNOPSIS...
Weak high pressure will extend into the Carolinas from the north
through Friday. Hot and humid air mass will spread into the region
for the weekend. Upper level disturbances will bring a chance of
thunderstorms.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1000 PM Thursday...
The Air Quality alert for most of central NC will continue through
midnight. Another Air Quality Alert will be in effect starting at
midnight for the NC Piedmont and go through midnight Sat. For now
the Coastal Plain remains code yellow for Friday. The 3-7 mile
visibilities due to smoke will linger into tonight, gradually
retreating nw through the night.
No major changes to the forecast with the evening update. Brought a
slight chance for showers into the NW a tad earlier, with some hi-
res guidance hinting at that. Lows still expected to be in the mid
to upper 60s.
Surface high pressure will slowly slide eastward through the mid-
Atlantic through tonight. Aloft, a disturbance will traverse the
ridge, propagating generally southeast from the OH Valley into the
TN Valley tonight. An MCS could develop over the OH Valley and move
southeastward toward the Carolinas, but its timing and track are
still a bit uncertain. Details should become a bit more clear over
the next hour or two as it develops, but then the question will be
whether it makes it over the mountains.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 123 PM Thursday...
Increasing heat and humidity / storm chances beginning Friday.
The flow pattern consisting of the strong mid/upper ridge over the
lower Mississippi Valley and a persistent NW flow around the ridge
from IL/MO SE into the central and southern Appalachians will edge
eastward in the coming days. This poses an increasing risk of
thunderstorms and higher heat/humidity in the coming days, beginning
Friday.
The latest CAMS indicate the MCS of tonight (IL/KY to TN) may send
MCV or outflow into western NC late tonight and Friday morning. The
latest HRRR indicates some redevelopment of scattered showers/storms
over portions of central NC, even before noon Friday. This seems
plausible given that western NC will be on the leading edge of the
return moisture and heat from the SW. This warm front will be
located over the region Friday. Then, another MCS is expected to
move SE from IN/KY into the central or southern Appalachians late
Friday or Friday evening. This MCS may have more potential to move
across the mountains late in the day or Friday evening. We will
carry chance POP for now, mainly Friday afternoon and night until we
can better pinpoint the timing/location of the best chance (favored
corridor) of thunderstorms. Right now, highest POP west and lower
POP far NE.
The air mass on Friday will support highs in the mid 80s NW to the
lower 90s S-SE. The higher heat and humidity will arrive especially
over the weekend (with the chance of storms going up, to offer some
relief).
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 305 PM Thursday...
Saturday and Sunday mid to upper level ridging will be present over
Central NC. By early next week a weak long wave trough will be
dominant across the region through late week. As a series of MCSs
move from the Ohio valley into the region over the weekend expect
highest chance pops on Saturday afternoon, Sunday early morning, and
again on Sunday afternoon. Medium range all models show multiple
rounds moving across the region over the weekend, but timing differs
slightly. By Wednesday, models begin to differ as another possible
wet pattern sets up for the Mid- Atlantic region as a cold front
movies into the region on Tuesday. This front is expected to linger
for the second half of the week reducing temperatures for Tuesday
and Wednesday to the low to mid 90s.
Along with the chance of rain over the weekend, the big story is the
heat. Summer is here, and it will be hot over the holiday weekend.
Temperatures in the 90s combined with dew points in the 70s will
result in heat indices in the low 100s on Saturday. Temperatures
will increase Sunday and Monday with highs in the mid to upper 90s
with heat indices in the 100-110 degree range. Thus, a Heat Advisory
should be expected at least one of the days especially for areas
south of the Triangle.
&&
.AVIATION /00Z THURSDAY THROUGH TUESDAY/...
As of 755 PM Thursday...
24 hour TAF period: Smoke originating from Canadian wildfires will
continue to support periods of VSBY restrictions of 3 to 6 miles in
a mix of haze through tomorrow. Ensemble/probabilistic forecast
guidance continues to indicate the potential for some brief LIFR to
IFR restrictions in fog/stratus between 10 to 13z, mainly INVOF
KFAY, where BL dewpoints are expected to increase into the upper
60s/near 70. Any fog/stratus that does develop tomorrow morning
should quickly scour between 13-14z.
Model spread is high and forecaster confidence is lower than normal
regarding the chances for showers and storms Friday morning and into
the afternoon/evening as upper disturbances embedded in the NW flow
aloft pass through the region. For now will keep any related sub-VFR
restrictions confined to the Triad terminals(KGSO/KINT). However, an
eastward expansion into KRDU and KRWI may be needed in future TAF
updates. -CBL
Outlook: A regime with late night and early morning fog and stratus
along with scattered afternoon and evening thunderstorms is expected
Saturday into Independence Day Tuesday. -Blaes
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Blaes
NEAR TERM...KC
SHORT TERM...Badgett
LONG TERM...CA
AVIATION...CBL/BLAES
Area Forecast Discussion
National Weather Service Blacksburg VA
1048 PM EDT Thu Jun 29 2023
.SYNOPSIS...
Hazy conditions will persist through the remainder of the day
due to smoke from wildfires in eastern Canada. A series of
upper level disturbances will bring rounds of hit-and-miss shower
and thunderstorm activity to the lower Mid-Atlantic into the
weekend. A cold front will pass across the region on Monday,
bringing a return of drier weather for the Independence Day
holiday.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1040 PM EDT Thursday...
No significant changes to the forecast late this evening. Had a
few showers develop over the West Virginia mountains around
sunset, but those have since diminished. Some hi-res guidance
does indicate showers may build back in over the mountains during
the early morning hours, but have not seen a lot of consistency
from the guidance in this. Regardless, have left a slight chance
in the western zones to account for this possibility.
As of 611 PM EDT Thursday...
Made some minor adjustments to temperatures this evening into
tonight utilizing the latest surface obs, their trend and
blended in the NBM. Modified cloud cover for this evening into
Friday morning. In general, increased clouds a little in the
west. Adjusted pops and weather for tonight into Friday morning,
shaped towards blend of HRRR and NAM. Low temperatures tonight
will range from the upper 50s in the mountains to mid 60s in the
piedmont.
Previous discussion:
As of 230 PM EDT Thursday...
Hazy conditions continue across the lower Mid-Atlantic this
afternoon due to smoke from wildfires in Canada, and multiple
Air Quality Alerts remain in effect this afternoon given the
high particulates that may cause respiratory problems for those
who are sensitive. Otherwise, satellite imagery indicates mostly
clear skies, with fair weather cumulus across the Piedmont, as
well as high clouds trickling in from the west due to
thunderstorms moving south over Kentucky/Tennessee. Another
thunderstorm complex over Illinois continues to make its way
east.
While the remainder of today will remain dry, high resolution
weather forecast models are coming into better agreement this
afternoon that the storms over Illinois/Indiana will make their
way east during tonight, with the eastern fringe of this
activity advancing to Interstate 77 by around sunrise Friday. By
that point, believe that the storms will have weakened
significantly, with mainly only rain showers remaining.
Uncertainty increases at this point in the forecast as to how
convection will play out during the day on Friday. Some data
suggests that the early morning storms will leave an outflow
boundary draped east of the Blue Ridge, which will provide the
focus for renewed convection with mid-afternoon heating. Other
data suggests that debris clouds will linger across the region
into early afternoon, limiting heating and therefore making for
a more muted redevelopment of shower and thunderstorm activity
on Friday afternoon. For now, will err on the side of a wetter
forecast, where storms may refire across our area with afternoon
heating, though this could change with the evening or overnight
shift as new data comes in. Went a couple degrees cooler for
afternoon temperatures for Friday, reflecting the possibility of
outflow from showers and storms before maximum heating occurs.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 140 PM EDT Thursday...
An upper level ridge over Louisiana will track east to the
southeastern coastal states over the weekend. Impulses are
expected to move along the outer rings of this ridge and over
our region into Saturday night. On Sunday, an upper level trough
will push a weak warm front north of the area.
Models agree that storms will move over the area Friday night
into Saturday night, but differ on timing, track and areal
coverage. For Friday evening, the first impulse should decay as
it sinks south into North Carolina. There is a Slight Risk for
severe storms from Summers County WV to Watauga County NC
westward. The rest of the area is in a Marginal Risk. A stronger
complex is likely Saturday and the entire area is under a
Slight Risk. For both events, damaging winds are the primary
threat. There is also a Marginal Risk for excessive rainfall
with each system. The passing of a warm front will change our
convection mode from organized to disorganized diurnal pulse
storms.
Temperatures will run near normal Saturday with upper 80s to
lower 90s east of the Blue Ridge and 80s west of the Blue Ridge.
Temperatures should be a few degrees warmer on Sunday. Heat
indices may hit triple digits in the piedmont Sunday afternoon.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 150 PM EDT Thursday...
The upper level ridge is expected to move over the western
Atlantic on Monday. Meanwhile, the upper level trough will move
across the Ohio Valley pushing a cold front over the region
Monday afternoon and evening. With a moisture-laden atmosphere
and ample instabilities, another round of strong to severe
weather is possible Monday, especially along and east of the
Blue Ridge. The passing of the front Monday means Tuesday July
4th may be clear of any rain as high pressure begins to build
over the region. High pressure should remain in the area into
Thursday.
Temperatures will continue to run near normal with warm
afternoons and muggy nights.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
As of 735 PM EDT Thursday...
Hazy conditions continue across the lower Mid-Atlantic this
evening into tonight due to smoke from wildfires in Canada,
resulting in widespread visibilities in the 3SM to 6SM range due
to haze. Otherwise, satellite imagery indicates mostly clear
skies, with high clouds and SCT VFR CU. Expecting CU fields to
dissipate with the loss of solar heating tonight. A few showers
or perhaps a storm may hold together to make their way into
western portions of the forecast area to near BLF by around
sunrise Friday. Believe convection will weakened significantly,
with rain showers remaining and a westerly wind shift late
tonight into Friday morning.
How storms develop for Friday afternoon becomes less certain as
some data suggests storms refiring across the Piedmont with
afternoon heating, and other data suggests that convection will
be muted due to residual clouds from morning activity that will
limit heating. While TAFs reflect some convection redeveloping
during Friday afternoon, have low confidence on the timing and
placement of this activity.
EXTENDED AVIATION OUTLOOK...
Friday night into Sunday, the opportunity for SHRA/TSRA
increases. Rounds of convection will continue to advance east
from the Midwest and Ohio Valley through this period. The
opportunity for rain will actually help clear the smoke/haze,
allowing for generally VFR outside of any sub-VFR restrictions
from the showers/storms. On Monday, sub-VFR showers and
thunderstorms are possible especially in the west. Scattered
MVFR convection is possible Tuesday especially in the mountains.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...NF
NEAR TERM...BMG/KK/NF
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...KK/NF