Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/21/22
Area Forecast Discussion
National Weather Service Burlington VT
1027 PM EDT Wed Jul 20 2022
.SYNOPSIS...
A few strong thunderstorms will be possible this afternoon across
northern and central Vermont before diminishing this evening.
Another hot and humid day is on tap Thursday with heat indices once
again around 95 degrees. In addition, strong to severe thunderstorms
will be possible Thursday afternoon from the Champlain Valley
eastward. These storms will weaken and exit the region on Thursday
with quieter and slightly cooler weather on Friday.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 1018 PM EDT Wednesday...A very warm and muggy night
prevails acrs the fa, with BTV crntly 84F over 69F as of 10 PM.
Did tweak pops acrs northern NY thru early Thurs, mainly to
lower values slightly below likely thru 12z, before expanding
quickly by 14z. Still a few rumbles overnight are possible, as
instability lingering overnight with warm temps and high dwpts.
Did a quick review of 00z data coming into the office this
evening and many parameters still look favorable for severe
storms. CAPE values should be in the 2000-2800 J/kg, with deep
layer shear of 35 to 40 knots with good height falls as
mid/upper lvl trof swings to our northwest. CAMs still have some
uncertainty on areal coverage and potential storm mode, but
given mainly unidirectional shear and associated straight
hodographs, thinking multiple cell clusters, evolving into
bowing line segments look likely. Mainly threat continues to be
damaging winds with hail and a potential quick spin up as
secondary threats. Convection should start firing btwn 10 and 11
AM acrs northern NY and quickly build and expand in areal
coverage/intensity as it encounters better storm relative
inflow associated with south winds 15 to 25 knots by noon or so
acrs the CPV. Otherwise, another warm and humid day on tap with
highs well into the 80s and locally near 90F parts of the CPV
and lower CT River Valley.
Previous discussion follows:
The upper level ridge axis appears to have settled across the
Adirondacks this afternoon and hasn`t quite pushed into Vermont.
This is evident in the recent radar images showing convection
firing across northern New York and moving into Vermont. The air
mass across Vermont is very unstable with recent LAPS and RAP
data showing upwards to 3000 J/kg of CAPE with 20-30 knots of
effective bulk shear. At this point, it doesn`t seem like there
will be any limiting factors to these storms continuing and
likely intensifying over the next few hours as there really
isn`t anything to inhibit thunderstorm develop. Ultimately, the
upper level ridge will continue to slide eastward as surface
instability begins to wane around sunset and should put a quick
lid on these storms. Quiet weather overall is expected to
continue through much of the evening and overnight hours as the
upper level ridge axis moves overhead but it`ll be warm and
humid with many places only seeing low temperatures fall into
the upper 60s to mid 70s.
Another very hot and humid day is on tap for Thursday. Given that
temps will struggle to fall during the overnight period tonight, it
won`t take long to see temperatures warm into the upper 80s to lower
90s across much of the region. The one fly in the ointment, and it`s
a big one, is at point does the convection associated with a
prefrontal trough develop across the western Champlain Valley in New
York. The latest guidance has sped up the arrival of a prefrontal
trough into the Champlain Valley around 11 AM or noon which could
potentially bring a quicker increase in cloud cover and rain cooled
air which would significantly limit heating. Anyways, back to the
thunderstorm potential. A prefrontal trough is expected to interact
with an airmass with attributes including 1500-2500 J/kg of CAPE, 30-
40 knots of effective bulk shear, and height falls aloft allowing
for good vertical velocities. The latest HREF from SPC shows strong
updraft velocities across the region during the afternoon hours which
would suggest strong to severe thunderstorms developing ahead and
along the prefrontal trough.
Another round of showers and thunderstorms is appearing increasingly
likely during the mid to late afternoon hours as a cold front begins
to move through the North Country. While the front is likely to
interact with a rain cooled air mass, the mid-level temperatures
will also be trending downwards. This will yield slightly lower CAPE
values closer to 1000 to 1500 J/kg but shear will still be
impressive and DCAPE values close to 1000 J/kg are expected to
persist. Given the early start to the convection, it looks like by 8
PM the bulk of the showers and thunderstorms will have either
dissipated or exited to our east which will bring an end to severe
potential on Thursday. Thursday night looks rather uneventful with
decreasing PoPs and some clearing skies.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 326 PM EDT Wednesday...The overall weather pattern that will
set up starting Friday and drive the weather through the weekend
will be driven by another upper low that will anchor in place near
southern Hudson Bay. We`ll remain on the southern periphery of the
low but within the track of multiple shortwaves moving through the
fast zonal flow. Friday looks like the best chances for dry weather
for most of the area despite the shortwaves transversing the region.
The air mass will be quite a bit drier on Friday than the previous
few days, and building surface ridging should suppress the
development of precipitation during the day. It will be another
toasty day however, with highs forecast in the low to upper 80s for
most of the area.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 326 PM EDT Wednesday...For Saturday, we`ll see better chances
for a few afternoon showers with increasingly zonal flow and some
weak shortwaves moving through. Saturday will be the warmest day of
the weekend, with many areas seeing afternoon highs in the mid 80s
to low 90s. Dewpoints in the low to mid 60s will make for another
warm and muggy mid- summer day. Any showers that do develop will
have a good chance of developing into thunderstorms given the amount
of instability present, though coverage is not expected to be
widespread.
Saturday night, a moisture boundary will move through and
precipitable water values will climb to around 1.75 inches. The
influx of moisture in combination with warm overnight temperatures
will setup an unstable environment by Sunday morning, with models
showing between 500 and 1500 J/kg CAPE by midday Sunday. As the
back end of the moisture/frontal boundary moves through during the
day, expect a line of showers and thunderstorms to develop. Highest
thunderstorm potential for Sunday will be over southern and central
Vermont where the boundary will move through the latest and
temperatures will climb into the upper 80s in valley locations. An
earlier frontal passage for northern NY and northern VT will keep
conditions a good 10 to 15 degrees cooler than areas further south.
From Monday onwards, we`ll see a pattern shift with the arrival of a
drier and cooler air mass from the northwest wrapping around high
pressure over the Great Lakes Region. Temperatures to begin next
work week will top out in the mid 70s to mid 80s each day, with a
gradual warming trend going into mid-week.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...Currently VFR, with light rain showers
moving across KMSS. Winds are trending southerly, and will
remain steady near 5 knots and then begin to gradually increase
after 06Z. Winds aloft will be increasing a bit more quickly,
especially over northern New York, and noted some LLWS at KMSS
and KSLK through about 09Z. After 09Z, winds should increase to
9 to 14 knots with gusts 16 to 24 knots, though a bit longer to
reach these speeds at KEFK and KMPV. Showers and an isolated
thunderstorm will approach KMSS and KSLK about 09Z to 11Z, and
move east into Vermont about 15Z to 17Z. Additional storms will
develop near or east of KSLK about 19Z to 22Z, moving east of
the region about 00Z Friday. With any of these rounds, there
could be a few storms capable of strong, gusty winds, frequent
lightning, and heavy rain that reduces visibility. At this time,
it seems storms will not merge into clusters or lines, but this
possibility is not out of the question. So most terminals have
a mention of VCTS, but have included in a tempo for KEFK, KMPV,
and KRUT where the chances will be highest, but the activity
could be hit or miss. As the front shifts east, winds become
southwesterly, remaining about 6 to 10 knots into 00Z Friday.
Outlook...
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. Chance SHRA, Chance TSRA.
Thursday: VFR. Likely SHRA, Chance TSRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR. Slight chance SHRA, Slight chance TSRA.
Friday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Saturday: VFR. Slight chance SHRA, Slight chance TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Clay
NEAR TERM...Clay/Taber
SHORT TERM...Duell
LONG TERM...Duell
AVIATION...Haynes
Area Forecast Discussion
National Weather Service Columbia SC
1000 PM EDT Wed Jul 20 2022
.SYNOPSIS...
Typical summer pattern with seasonable temperatures and mainly
diurnal showers and thunderstorms through Thursday. A front will
be near the area late Thursday bringing higher chances of widespread
thunderstorms that may produce damaging wind gusts north and
west. Warmer and slightly drier this weekend into early next
week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
The main upper trough has pushed through and the axis has moved over
the coast. Surface winds continue to be from the south/southwest and
moisture transport remains high over the forecast area. Mighty moist
environment with PWATs over 2 inches and dewpoints in the upper 70s.
Both DCAPE and MUCAPE have decreased significantly over the past
hour and the isolated thunderstorms within the CWA have dissipated.
Later tonight, a weak upper impulse is expected to shift over the
area but confidence in timing and extent is still a bit uncertain.
Looking at MRMS there are several showers moving down from the
Upstate of SC and northern GA and will near the area overnight.
These will likely dissipate by the time they near our CWA. Past
that, some of the most recent CAMs show the boundary currently
in Kentucky and Tennessee traveling south and bringing down
better organized storms near daybreak. Have kept chance/slight
chance PoPs overnight as timing remains the biggest uncertainty.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
General upper troughing remains over the area Thursday with some
HiRes models indicating lingering convection into the morning,
similar to what was observed today. It does appear, however, that
the axis of the upper trough should shift farther to the east which
may keep any morning convection in the Coastal Plain. The evolution
of morning showers or storms will be important to how things play
out into the afternoon as a cold front drops into the southern
Appalachians. While the front likely remains NW of the forecast
area, storms will develop along it and move southeast into the
forecast area. HREF mean shows moderate to strong destabilization
across the forecast area by the afternoon into the evening. While
deep layer shear will be fairly weak, 850mb winds will increase to
around 20 to 30kts. As PWATs increase to around 2.25 inches, precip
loading and increased low level winds will support a damaging wind
gust threat, especially across the northern and western portion of
the forecast area, where SPC has outlined the area in a slight risk.
The timing for the highest chance of severe weather appears to be
tomorrow evening. Any storms that move into the area will likely
encounter the sea breeze as well which would help to enhance
convergence over the forecast area. With PWATs above 2 inches,
there will be a bit of a flooding threat, although the general
steering flow should be strong enough to limit flash flooding
outside of any training storms. The area to watch would be
where the sea breeze and storms coming from the NW meet,
especially if this occurs over an urban corridor. Temperatures
will generally be seasonably hot tomorrow with SW winds
reinforcing the warm, moist airmass. Heat indices as a result
will generally max out around 105 for most of the area.
Overnight lows in the low to mid 70s.
Friday, lingering boundaries will be in the area and the airmass
remains moist. Convection will likely be a bit more scattered with
less forcing compared to Thursday. Highest chance of showers and
storms will be in the southeast area in an area of convergence along
a lingering boundary and the sea breeze. A few degrees cooler with
increased clouds across the area and at least a chance of lingering
showers in the morning. Still, highs will be in the low 90s
with dew points remaining in the 70s will make Friday feel
fairly similar.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Upper level ridging will be building over the area in the long term
period. NAEFS indicate that heights will be above the 90th
percentile with a strengthening of the Bermuda High off the coast.
This will support temperatures continuing to be a few degrees above
average with south-southwesterly flow keeping dew points generally
in the 70s through the period. Ensemble suites generally support the
pattern remaining fairly persistent through early next week with a
weakening of the ridge by midweek as an upper trough amplifies
towards the end of the period. Majority of ensemble members show
moderate destabilization each day with PWAT values around average.
With a lack of a significant trigger, this supports a general
summertime pattern with isolated to widely scattered thunderstorms
each afternoon and slightly above average temperatures.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Generally VFR conditions are expected through the evening and
overnight hours although some morning stratus cannot be ruled
out.
Isolated to scattered storms are around the area this evening
but none immediately impacting any terminals so will leave out
at this time and amend as needed. Upper trough axis will shift
east of the area tonight and some lingering showers may be
present through the predawn hours but again confidence is low in
impacts to terminals.
HRRR and SREF hinting at possible morning stratus so included a
tempo group from 10z-14z as confidence is a bit low. Do not
expect fog to be an issue with winds staying up overnight and a
20 knot low level jet.
Relatively high chances of convection tomorrow with some strong
to severe storms possible with strong wind gusts in excess of 40
knots and heavy rain could reduce vsbys at times. Included a
mention of thunder after 18z. Winds on Thursday should pick up
to around 10 knots with gusts up to 20 knots outside of
thunderstorms.
EXTENDED AVIATION OUTLOOK...Scattered mainly afternoon and
evening thunderstorms Thursday, and possibly again Friday but
favoring southern areas, along with some possibility of patchy
late night/early morning fog/stratus. Drier over the weekend
with a lower chance of restrictions.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Dodge City KS
545 PM CDT Wed Jul 20 2022
...UPDATE TO AVIATION...
.SHORT TERM...(This evening through Thursday)
Issued at 352 PM CDT Wed Jul 20 2022
Mid/high level cloud, a few scattered showers, and a northeast wind
kept temperatures at bay as compared to the past several
days...especially yesterday. A small mesoscale convective vorticity
(MCV) max was located across the eastern Panhandles with influence
northward toward our southern counties from Liberal to Englewood.
Small showers will continue in this region through late afternoon,
and there may be a couple lightning strikes, but the atmosphere is
quite stable to deep, moist convection.
Tonight, a larger MCS will develop and track east-southeast across
eastern Colorado. This MCS will make a run at our far western
counties later this evening, likely after 02Z (9 PM CDT), and will
also be in a weakening phase as it makes its way into far southwest
Kansas. Thus, we will be keeping 20-30 POPs only right up against
the Colorado border. The HRRR shows quite a bit of outflow wind with
its modeled MCS, so the evening crew will need to monitor this
potential wind threat later in the evening across our far southwest.
Another MCV will likely remain after the MCS dies to our south, and
this may reinvigorate showers/isolated thunder across our far
southern counties -- the same general region where the showers were
occurring this afternoon.
Later Thursday afternoon, additional isolated to widely scattered
showers/storms may develop, but the anticipated coverage does not
look all that great given absence of appreciable low level
convergence. We will keep POPs below the mentionable 15 percent for
much of the area, as a result. As far as temperatures are concerned,
we will likely see an uptick in afternoon temperature by a couple
degrees over this afternoon`s temperature, but this is based on a
mostly sunny sky much of the day. There may be enough mid/high cloud
to keep temperatures in check across the southern portion of the
forecast area (south of the Arkansas River).
.LONG TERM...(Thursday night through Wednesday)
Issued at 352 PM CDT Wed Jul 20 2022
The trend toward a return to 100+ heat is still on track. Saturday
and Sunday still look like the hottest days in the Long Term ahead
of the next cold front. Increased model agreement on Saturday
afternoon`s temperature resulted in a bump up in the NBM MaxT, with
a larger area of 106-107F in the grids now for Saturday`s high. It
will not be too surprising to see a couple 108 to even 110F if the
thermal ridge is as pronounced as the latest model runs have it
across west central/northwest Kansas. As mentioned in previous
discussions, Sunday`s forecast is a bit more difficult based on the
timing of the front. locations just out ahead of the front on Sunday
will almost assuredly exceed 106F. The ECMWF, Canadian GDPS, and GFS
models all differ on the front placement after Sunday. The ECMWF
model is more ambitious about the front pushing through southwest
Kansas on Monday providing another break from the heat...although
for only a day. The ECMWF builds the heat back north into
southwest/west central Kansas on Tuesday. The global deterministic
models continue to show a favorable signal of the polar front
pushing all the way through by Wednesday Night or Thursday of next
week, but this is 6-7 days away, and a lot will likely change in
this forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 543 PM CDT Wed Jul 20 2022
VFR conditions will prevail in vicinity of all TAF sites through early
Thursday afternoon. South-southeasterly winds around 5 to 15kt are
expected to continue through early Thursday as surface high pressure
slides southeast across eastern Kansas during the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 71 100 70 102 / 10 10 10 10
GCK 69 97 67 102 / 10 10 10 10
EHA 71 95 68 99 / 40 20 10 10
LBL 71 98 68 101 / 20 20 10 0
HYS 69 100 71 103 / 10 10 10 10
P28 73 102 72 102 / 10 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...JJohnson
Area Forecast Discussion
National Weather Service Grand Rapids MI
913 PM EDT Wed Jul 20 2022
LATEST UPDATE...
Update
.UPDATE...
Issued at 913 PM EDT Wed Jul 20 2022
We have a narrow band of convection (no thunderstorms at this
point) moving over the Muskegon area at 9 pm this evening. There
is between 500 and 800 j/kg of MU cape to work with and it is on
the right front exit region of jet core over WI. I expect this
will hold together for the next few hours it is forced by mid
level dynamics and not surface based heating. The showers will
mostly stay near and west of US-131. The showers at any one place
will last less than 30 minutes but some will bring brief heavy
rainfall rates even without thunder. Skies should clear after
midnight.
UPDATE Issued at 631 PM EDT Wed Jul 20 2022
I took the thunder out of the evening forecast since looking at
model sounding and also looking at the RAP model mixed layer cape
for the this evening there is not enough instability for the
showers moving into our area this evening from WI to become
thunderstorms (they are not thunderstorms now either).
Also I added 20 to 30% pops to our forecast Thursday evening as
there is a shortwave moving through our southern CWA. We are in
the left exit region of the jet core and we have warm advection at
low levels we cold advection at high levels. The MU cape increase
to near 1000 j/kg south of I-96 during Thursday evening as that
shortwave moves through. Both the HREF and SREF 06 hour
probability of 0.01" is between 20 and 40 percent south of I-96
then too. This will not be a big event but there will be scattered
showers moving through the area. I adjusted the cloud forecast to
match the precipitation forecast so that would make sense.
As a side note, I do expect to end the small craft advisory and
beach hazards as per there forecast expiration since looking at
we beach cams and some buoy data, conditions continue to improve.
&&
.DISCUSSION...(This evening through next Wednesday)
Issued at 305 PM EDT Wed Jul 20 2022
...A Few Showers/Storms This Evening...
Mid level height falls continue this evening as the closed low
over tracks eastward through the northern Great Lakes Region.
Relatively deep cyclonic flow will persist over portions of the
CWA this evening leading to some upward forcing. MU CAPE values
from the latest HRRR are pointing to instability persisting this
evening with especially closer to the lakeshore. We will maintain
a low risk for showers and storms this evening...mainly for the
western half of the CWA A narrow line of relatively shallow
convection has developed from near Lansing to Battle Creek. This
line was tracking east and should push east of Jackson by 430 pm.
Surface dewpoints have already dropped off into the 60s.
...Gusty winds diminishing late this afternoon into the evening...
Based off of the KGRR VWP fairly deep 30 to 40 knot winds exists
within the mixing layer. Surface values have generally been in the
30 to 35 knot range with a few briefly higher gusts recorded.
Scattered power outages have been ongoing all afternoon. As the
mixing height drops off later this afternoon into the evening...so
will the surface gusts.
...Still looking at a higher potential for showers/storms Saturday
night into Sunday...
A stronger upper level jet in zonal flow is shown to push
eastward through the Upper Plains Saturday evening into the night.
Meanwhile a low level jet will be nosing into the WI/Northern IL
region...advecting in abundant moisture. With favorable
instability in place...it appears an MCS will get going. Based on
the projected movement of this feature...the CWA could see a round
of showers/storms through the night. There is still some
uncertainty on this...but the models have been showing this for
several runs. We will maintain higher POPs for this potential
event.
...Another round of storms possible Wednesday...
There is some general agreement in the models in showing a cold
front tracking through the CWA on Wednesday. The atmosphere is
shown to moist and unstable ahead of this feature with a deep
southwest flow out ahead of the front stretching down into the
Gulf. Relatively fast flow is shown to exist in the mid
levels...which leads to decent deep layer shear. We will feature a
risk for storms in this period and will need to monitor the severe
risk as we near this timeframe.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 728 PM EDT Wed Jul 20 2022
I am thinking solid VFR conditions through Thursday. That being
said, there is an area of showers over WI, north of MKE, that is
moving quickly to the southeast. This will bring a period of very
light rain showers to most of the TAF sites between 8 pm and
midnight. Skies will clear after that.
It should be mostly sunny Thursday. The next system brings
increasing clouds mid to late afternoon with showers possible
after 00z on Friday. The winds will becoming gusty once again but
not nearly as gusty as there were today.
&&
.MARINE...
Issued at 807 PM EDT Wed Jul 20 2022
Wind gusts are below 15 knots at all near shore sites and near
shore buoys. The wave heights across our near shore waters at all
buoys are 2 feet or less. So, I have allows the headlines to
expire.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...WDM
DISCUSSION...MJS
AVIATION...WDM
MARINE...WDM
Area Forecast Discussion
National Weather Service Wilmington NC
944 PM EDT Wed Jul 20 2022
.SYNOPSIS...
A mid-level trough will drift east over the area the next few
days, maintaining afternoon storm chances. A cold front will
approach Thursday before stalling to the west of Friday,
bringing unsettled weather through the end of the week. A strong
ridge of high pressure will build into the Southeast this
weekend with above normal temperatures expected across the
Carolinas.
&&
.UPDATE...
Update this evening has mainly focused on updating PoPs based on
radar trends. Late afternoon/early evening convection has
dissipated, and cluster just NW of the CWA is weakening rapidly.
Will carry a small chance PoP far inland for a couple more
hours, then only slight chance for the duration of the night, as
instability has become marginal with the loss of heating. HRRR
had been indicating redevelopment east of I-95 late tonight,
but last few hours it has backed off. Latest guidance suggests
that most redevelopment will hold off until after sunrise. A
Heat Advisory remains in effect for Thursday, as high temps in
the mid 90s and dewpoints in the mid 70s combine to produce heat
indices of 106-108 away from the immediate coast. The extent of
convection could play a role in keeping heat indices lower than
currently forecast, especially if it fires up early.
Winds over the area waters are gusting 25-30 kt with seas
running around 6 ft. Small Craft Advisory remains in effect
tonight through Thursday night.
&&
.NEAR TERM /THROUGH THURSDAY/...
Convection ongoing, should endure through at least 8pm if it doesn`t
push off the coast earlier. Slightly cooler temperatures aloft
associated with little trough feature is allowing for possibility of
hail this afternoon with more robust CBs that shoot up or above 40
kft. Plentiful CAPE, and large downdraft CAPE values make localized
damaging downbursts a possibility as well through at least afternoon.
The pattern of reflectivity shows how the upper trough is involved,
with some inklings of organization. Quieting, breezy overnight in
boundary layer ahead of approaching trough, this to prevent fog.
Pre-frontal trough and heating Thursday to allow for 2 rounds of
convection potentially. Large SBCAPE expected, could enhance
downburst damage potential. The SPC placing us in marginal risk of
severe TSTMs Thursday, slight risk to our west. Strong heating and
high dewpoints requires a heat advisory for Thursday.
&&
.SHORT TERM /THURSDAY NIGHT/...
In the mid-level, the trough over the east coast will be its deepest
and gradually weakening through Friday night. A cold front will be
approaching the Appalachian Mountains at the surface and stall over
the Carolina Piedmont. A 500 mb short-wave pressure trough will be
over the region on Thursday and moves out of the forecast area
Thursday night. This trough will provide synoptic lift reflected in
the model omega fields. 2" plus precipitable water will be over
the region through the period. The 0-6km storm motion indicates
cells will be between 10 to 15 knots. So isolated areas will
receive heavy rain, and strong wind gusts from the thunderstorms
Thursday are possibly isolated, especially in areas away from
the coast.
As the frontal boundary weakens and leaves our area, the warm moist
environment will remain entrenched for the entire period.
Highs on Friday will reach the lower 90s inland and the upper 80s at
the beaches. Heat Indices will reach into the lower 100s just
below criteria for much of the area. The scattered thunderstorm
can be expected to help moderate these heat indices. Low are
expected in the middle 70s inland and upper 70s at the beaches.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
The forecast has not changed much over the past 12 hours. The
Bermuda high-pressure ridge will be set up to the east, and
troughs in the eastern United States are expected to be weak
through the period and will not have much impact to our area. A
dominant southwest flow with diurnal convection each day is
expected. Temperatures will warm, and heat indices will be above
100 degrees most days and will be close to heat advisory each
day.
Highs each day will approach the middle 90s inland to near 90 at the
beaches. Lows are expected in the middle 70s inland and the upper
70s at the coast.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Isolated convection is ongoing within our CWA but impacts should
be minimal to none as storms fizzle out with loss of heating.
We will monitoring a line of storms to our NW which could impact
KFLO and KLBT within the next couple of hours. Some guidance is
showing the possibility of shortwave energy moving in overnight
which could reignite storms. SW winds will return tomorrow
gusting around 20-25kts as a cold front approaches the area.
Showers and storms could pop up earlier in the day near this
boundary.
Extended Outlook...Sub-VFR conditions possible each day in
showers and thunderstorms, with the greatest chance in the
afternoon/evenings. Stratus and fog may produce mainly MVFR
visibilities or ceilings overnight into early mornings.
&&
.MARINE...
Through Thursday...
Advisory ongoing for SW gusts between 25-30 kt and 6 ft seas
offshore. Additionally, TSTMs will add another layer of hazard this
forecast period, as an approaching surface trough interacts with
Bermuda High pressure offshore. Strong SSW wind-seas, steep and full
of chop, will mix with SE waves of 1-2 feet every 8-9 seconds, the
Bermuda swell. TSTMs will cause locally higher winds and seas, and
dangerous cloud to water strikes this period. Seas should peak at 6-
7 feet late Thursday offshore mainly in steep SW wind-waves before a
slow.
Thursday Night Through Monday...
A front will approach but stall over
the Piedmont beginning Thursday night. The pressure gradient between
the trough and the Bermuda high will weaken. Southwest winds are
expected throughout the period. Wind speeds near 20 knots will occur
Thursday evening, and the winds will weaken by 10 to 15 knots by
Saturday evening and remain at this speed through Monday.
Sea heights will drop for 5 to 6 feet Thursday evening, subsiding to
3 to 4 feet by Sunday into Monday.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Heat Advisory from noon to 8 PM EDT Thursday for SCZ017-023-
024-032-033-039-054>056-058-059.
Beach Hazards Statement from 6 AM EDT Thursday through
Thursday evening for SCZ054-056.
High Rip Current Risk from 6 AM EDT Thursday through Thursday
evening for SCZ054.
NC...Heat Advisory from noon to 8 PM EDT Thursday for NCZ087-096-
099-105>110.
Beach Hazards Statement from 6 AM EDT Thursday through
Thursday evening for NCZ106-108-110.
High Rip Current Risk from 6 AM EDT Thursday through Thursday
evening for NCZ110.
MARINE...Small Craft Advisory until 5 AM EDT Friday for AMZ250-252-254-
256.
&&
$$
SYNOPSIS...ILM
UPDATE...CRM
NEAR TERM...08
SHORT TERM...RH
LONG TERM...RH
AVIATION...LEW
MARINE...08/RH
Area Forecast Discussion
National Weather Service Nashville TN
804 PM CDT Wed Jul 20 2022
...New UPDATE...
.UPDATE...
Issued at 753 PM CDT Wed Jul 20 2022
It`s a warm and juicy evening across Middle Tennessee. The
majority of the obs are still 90 degrees or above with dew points
in the 70s. The heat advisory and excessive heat warning were
allowed to expire for the evening. Wayne, Lawrence, and Giles
still have the heat advisory for Thursday from 10am-6pm.
Looking at the 00z OHX sounding, there`s ample CAPE this evening
with mlCAPE values around 3500 J/kg and surface based CAPE values
around 4500 J/kg. Shear is on the weaker side with 10 kts of
effective shear, but looking upstream into southern KY, 20 to even
25 kts can be found. The better shear values upstream are expected
to make it into our area later this evening. High resolution
models have been showing storm development that is starting to
occur in southern Kentucky and even the northern part of our area.
Some of this wave is expected to clip the northeast part of Middle
Tennessee later this evening. Some damaging wind gusts cannot be
ruled out with that activity. The other area to watch is the
activity along the Kentucky/Illinois border. HRRR has come more in
line with the NAM 3km in bringing that wave of storms into the
area around midnight and later. Even with the overnight time
period, ample CAPE will still be around along with 20-25 kts of
effective shear. Therefore, damaging wind gusts will remain a
threat overnight.
&&
.SHORT TERM...
(This afternoon through Thursday Night)
Issued at 219 PM CDT Wed Jul 20 2022
The theme for the short term is definitely HOT, maybe some rain,
and not as hot. But before we get to the good part, Highs today
have been well into the 90s with heat index values solidly in the
mid 100s this afternoon. However, a nice little front will push
through the area overnight bringing showers and thunderstorms to
much of Middle Tennessee. A few of those storms could be strong
overnight, but definitely not expecting widespread severe weather.
Thanks to the above mentioned front, think most of Middle
Tennessee will be free from any Heat Advisory or Excessive Heat
Warning outside of far Southern Middle Tennessee on Thursday. I
think we can all agree that heat index values in the 90s are
slightly better than the 100s. But just slightly.
&&
.LONG TERM...
(Friday through next Wednesday)
Issued at 219 PM CDT Wed Jul 20 2022
Hot and dry weather pattern sets up Friday through at least Monday
with temperatures returning to the mid to upper 90s and heat
index values racing back to the 100s. Another round of Heat
Advisories and maybe even Excessive Heat Warnings will likely be
needed for the weekend. The next chance of rain after tonight
looks to be Tuesday and into the middle of next week as we return
to a not as hot weather pattern with typical summertime afternoon
and evening convection.
&&
.AVIATION...
(00Z TAFS)
Issued at 547 PM CDT Wed Jul 20 2022
Hot and unstable airmass in place across the mid state this
afternoon. However, large subsidence is the rule and for the most
part is preventing any convective activity at this time across
middle TN. There is a cold front a couple hundred miles off to our
northwest with some pre frontal convergence now taking shape just
north of the Ohio river. As the front slowly drops southward...we
will see this developing area of convection move our way
overnight. Thunderstorms will be possible for the taf areas as
early as 02Z in the far NW near CKV, then for the BNA and CSV
areas as we move toward 06Z-08Z. For now, will add some convective
wind gusts but that may need to be increased going forward.
Otw, after the storms move out, which will be by 10Z or so, we
should have more tranquil conditions. Look for light northwest
surface winds on Thursday with lower humidity by the afternoon.
Still rather hot with highs in the 90s still. Cloud cover will be
generally scattered with a trend toward "few" as we reach the mid
afternoon hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 75 95 71 97 / 50 10 0 10
Clarksville 73 95 68 98 / 40 0 0 0
Crossville 69 87 66 90 / 50 20 10 10
Columbia 74 95 69 96 / 40 0 0 10
Cookeville 71 90 67 91 / 50 10 10 10
Jamestown 69 87 67 90 / 50 20 10 10
Lawrenceburg 73 94 69 95 / 40 10 0 10
Murfreesboro 73 95 69 96 / 40 10 0 10
Waverly 74 95 70 99 / 40 0 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 10 AM to 6 PM CDT Thursday for Giles-Lawrence-
Wayne.
&&
$$
UPDATE.......Reagan
SHORT TERM...Hurley
LONG TERM....Hurley
AVIATION.....21
Area Forecast Discussion
National Weather Service Pocatello ID
235 PM MDT Wed Jul 20 2022
.SHORT TERM...Tonight through Thursday night.
Satellite imagery shows weak disturbance over northern Utah,
slowly shifting east around the apex of 4-Corners high. Deeper low
over northeast Pacific beginning to eject shortwave northeast
toward Seattle early this afternoon. WSW flow aloft helping to
keep moisture generally confined to areas directly adjacent to
Idaho/Utah border. There could be enough instability for an
isolated thunderstorm or two through the evening tonight as
depicted by the hi-res guidance this morning. Otherwise the
remainder of the forecast area is expected to remain dry. Similar
conditions exist for Thursday, though aforementioned shortwave has
now positioned itself along the PacNW coast from Seattle to
Portland. Starting to see a response to this feature in the mid-
level wind fields mainly across portions of the central mountains
Thursday afternoon into the overnight, making for breezy
conditions at ridge top. Shortwave drives east through the Idaho
panhandle into Montana Thursday night and Friday, with most of the
impact from this feature falling into the extended time range.
DMH
.LONG TERM...Friday through Wednesday.
Upper shortwave drives east across the region Friday. Winds
increase through the afternoon and early evening. Enough moisture
could be pulled north into the region for isolated thunderstorms
mainly higher elevations. Winds and humidities remain the greatest
concern, with impacts for fire concerns across East Idaho.
Conditions settle down Saturday as upper ridge tries to build into
the region, though a lingering thunderstorm or two may still be
possible. Another feature drives east Sunday for another
potentially windy day, with continued fire related concerns.
Ensemble clusters are all in favor of feature sliding through the
PacNW at this time, though they do differ slightly on strength and
depth of the feature. Monday and early Tuesday slightly cooler
behind Sunday system under influence of northwesterly flow. Upper
ridge strengthens again late Tuesday into Wednesday, stretching
through the Great Basin toward the PacNW. GFS/ECMWF are slightly
different in handling the ridge axis, leading to potential
differences in temperature and wind trends through mid week.
Conditions do look dry across the board however. DMH
&&
.AVIATION...
For the 18Z TAFS through 18Z Thursday.
An area of high pressure will dominated the next 36 hours of the
forecast. We are expecting some convective clouds over the higher
terrain this afternoon especially along the southern parts of Idaho`s
higher terrain. Ceilings will remain FEW to SCT becoming BKN at
times across southern higher elevation zones associated with better
chances for storm development. Afternoon showers, virga, and
isolated thunderstorms will remain confined to the South Hills and
Southeast Highlands south of the Snake Plain with HREF lightning
probabilities increasing to a 10 to 20 percent chance of occurrence
along the Utah and Nevada border regions. Best chances for VCTS will
remain at KPIH and KBYI. Winds will also pick up this afternoon
between 8 to 12 kts with gusts up to 20 kts. Clear skies return
after sunset as chances for afternoon showers and storms tracks
further south for Thursday. HRRR Smoke guidance shows continued
smoke impacts today aloft from the Moose and Bray fires currently
burning in the Salmon Challis NF and Magic Valley respectively. A
westerly component to upper level flow will support smoke impacts
above all terminals with best chances for near surface smoke across
the Lemhi Valley, Upper Snake Plain, and Eastern Highlands.
MacKay/Preston
&&
.FIRE WEATHER...
Upper ridge in place for now, but changes are forthcoming. Some
lingering monsoonal moisture pooled over Utah has a finger or two
stretching north into southern Idaho. Isolated storms remain
possible along the Utah border through the evening, and afternoon
winds are expected to be locally breezy but below critical fire
thresholds. Similar conditions are expected on Thursday. A
disturbance passes through the Idaho panhandle into Montana on
Friday. Models have been trending slightly stronger with the wind
threat, and all conditions are in place for a critical fire day,
especially across the Salmon/Challis NF areas and the Upper Snake
Plain. Combination of winds and humidities may approach critical
thresholds in the Lower Snake Plain, and lower elevations of the
Southern Sawtooth and Caribou NFs as well. Fire Weather Watch has
been issued, and may be expanded if conditions warrant. A few
thunderstorms may be possible as well as the disturbance pulls
some moisture north into the region. Conditions settle down for
Saturday, but a second disturbance shifts through on Sunday for
another potential wind event and the next potential day of
critical fire concern. DMH
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Friday morning through Friday evening
for IDZ410-475-476.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
1015 PM EDT Wed Jul 20 2022
.SYNOPSIS...
A cold front will approach from the northwest, then stall and
dissipate over central North Carolina late Thursday night through
Friday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1014 PM Wednesday...
Lingering convection is rapidly dissipating with the loss of heating
late and exiting mid-level wave. Just a few areas of rain remain as
of 10 PM but expect dry weather by midnight. With nocturnal
stabilization, do not expect re-development of storms overnight,
however the HRRR is still showing some showers early Thu morning
across central NC, while other CAMs remain dry. Will keep the slight
chance for convection early Thu, but confidence is low that it will
materialize. As per the previous discussion, increasingly-
moist/humid low levels will likely result in the development and
maintenance of areas of stratus/stratocumulus late tonight through
late morning Thursday. Lows should bottom out in the low to mid 70s.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 400 PM Wednesday...
A Heat Advisory has been issued for the Coastal Plain, Sandhills,
and portions of the northeast Piedmont of cntl NC for Thu afternoon-
early evening.
A broad trough from the Northeast nwwd across cntl and wrn Canada,
and associated cyclonic flow aloft, will glance the srn Mid Atlantic
this period. Wly 700-500 mb flow will consequently increase across
cntl NC, ranging from around 15-20 kts over srn NC to 25-30 kts
across nrn NC.
At the surface, a lee trough will again sharpen over the NC
Foothills and wrn Piedmont with diurnal heating, while a synoptic
cold front will drift sewd and likely reach the NC Piedmont by Fri
morning, where it will subsequently stall and dissipate.
Continued swly flow ahead of the front will result in a slightly
hotter and more humid airmass over cntl NC on Thu relative to
previous days, with high temperatures in the low-mid 90s. When
combined with afternoon dewpoints in the upr 60s to lwr 70s over the
nw Piedmont to mid-upr 70s over the Coastal Plain, heat index values
are expected to climb above 100 F throughout cntl NC, and above 105
over roughly the ern half of cntl NC. That heat and humidity will
also favor the development of moderate instability, highest
southeast, which should fuel scattered to locally numerous afternoon
and evening storms, some of which may cluster into loosely-organized
line segments capable of scattered damaging wind gusts. High Pws
between 1.6 and 2.0" will also favor heavy rain and localized
flooding. Areas of stratus and fog will result in the rain-cooled
air overnight, with lows in the lwr-mid 70s.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 230 PM Wednesday...
Heights aloft will increase late this week into this weekend as the
upper trough to our north flattens and ridging to our west expands
east. H500 heights will increase from 590 dam Friday to 593 dam by
Sunday, with increased warming and drying aloft. H1000-H850
thicknesses remain steady between 1430-1450 m through the period. A
stalled front to our northwest Friday will push back north over the
weekend, with an Appalachian lee trough developing across our area
and the Bermuda high set up to our east. The northwestern half of
central NC will likely be too dry and stable for showers and storms
to develop Friday through Sunday, however precipitable water values
near 2" will linger near the coast through the weekend, and will
likely be high enough to develop diurnal convection, especially
Friday. There will be plenty of CAPE to support strong updrafts, but
lacking shear will limit overall storm organization and likely
result in short-lived pulse-type showers/storms.
The ridge building in will increase highs from the low to mid 90s on
Friday to the mid to upper 90s over the weekend. Heat index values
will increase to the low to mid 100s for most areas, except for the
Triad where lower dewpoint temps in the upper 60s will limit heat
indices to the upper 90s. Wet Bulb Globe Temps (WBGTs) will rise
into the high to extreme categories on Saturday, with most areas in
the high category Friday and Sunday. These temperatures will create
an increased risk for heat illness, and a Heat Advisory will likely
be needed for several areas. Little relief will be provided
overnight as lows only dip into the low to mid-70s.
Ensembles are now trending towards lower heights aloft early to mid-
next week with the ridge flattening and moving further west and a
deeper trough developing across the Northeast. This will help lower
highs slightly to the low to mid 90s, but also allow higher PWs to
filter into the region and increase chances of diurnal convection,
especially near the Appalachian lee trough. Unfortunately, the
increasing moisture will continue heat index values in the upper 90s
to low 100s early/mid-next week and WBGTs in the high category of
heat stress for most areas.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 740 PM Wednesday...
24 hour TAF period: Showers and storms will move eastward through
the area this evening, though if/when it clips the terminals is
still uncertain and for now they are slipping between them all
(closest at KINT/KGSO at TAF issuance). These storms should fall
apart with loss of heating later this evening. However, some
guidance suggests a regeneration of showers late tonight/early Thu
morning, which could impact some terminals. Also of likely to occur
(but low confidence on timing at a given terminal) will be the
development of IFR-MVFR cigs tonight/Thu morning. Scattered storms,
capable of 40-50 kt wind gusts, are expected Thu aft/eve. -KC
Looking ahead: Areas of fog and stratus are likely late Thu night-
Fri morning, particularly where the heaviest rain occurs beforehand.
A lingering chance of both morning stratus/fog and afternoon
showers/storms will focus over srn and ern NC through early next
week. -MWS
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon to 8 PM EDT Thursday for NCZ010-011-024>028-
040>043-075>078-084>086-088-089.
&&
$$
SYNOPSIS...MWS
NEAR TERM...KC
SHORT TERM...MWS
LONG TERM...JJT
AVIATION...KC/MWS