Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/26/18
Area Forecast Discussion
National Weather Service Sioux Falls SD
1054 PM CDT Mon Jun 25 2018
.SHORT TERM...(This evening through Tuesday)
Issued at 339 PM CDT Mon Jun 25 2018
Currently, satellite imagery is showing the upper low just about in
the middle of Nebraska, with a surface low centered in southeast
Nebraska. The various models are in good agreement in bringing the
upper low eastward to along the Missouri River of Nebraska and Iowa
by 06Z Tuesday, moving into northeast Iowa by Tuesday afternoon.
The main concern late this afternoon and evening is of course the
potential for heavy rain, or at least pockets of heavy rainfall. The
chances for severe weather in northwest Iowa and adjacent
locations are becoming more remote as the clearing line has remained
to the south, not allowing for a destabilization of the atmosphere.
With the upper low slow close, would not be surprised to hear
reports of a few funnels late this afternoon along and south of I 90
due to vorticity, but the threat for bona fide tornadoes is
The rainfall threat remains however, but this upper low is quite
different then the upper low of last Wednesday and Wednesday night.
First of all is not quite as strong. Secondly, the strongest
dynamics are mainly confined to the time frame of right now through
mid this evening, as QG forcing pinwheels northward from the upper
low and extends from our eastern zones, back into southwest Nebraska
at 00Z. However the QG forcing greatly decreases in strength between
00Z and 06Z tonight. So there is a question on just how heavy the
rainfall will be. If we did not already receive a ton of rain in the
previous week, we would not need a flash flood watch this evening as
there will likely not be the barn burner 3 to 7 inch amounts which
have been common recently. Instead, current thoughts are that there
will be pockets of heavier rainfall when cells would happen to train
for a couple of hours allowing local amounts to top an additional
two inches through midnight. However believe widespread amounts will
be in the three quarters of inch to inch and a half range. And the
heavier amounts will be confined to along and south of I 90. The
individual cells bringing the heaviest rainfall should be fairly
progressive as the whole thing lifts northward, before weakening
late this evening.
Earlier, already extended the flash flood watch area in time through
04Z this evening. After 04Z, the various CAMs show a great decrease
in rainfall both in coverage and intensity. In fact, the HRRR and
HRRRx really keep the heaviest rainfall confined to the MO River
On Tuesday on the backside of the upper low, lingering showers and
isolated thunderstorms will be a threat mainly east of the James
River valley. Sounding profiles are moist through 4km with mid level
temperatures near 700mb less than +10C. So therefore it will not
take much to get a shower going here and there. But the activity
will be isolated to scattered as forcing by Tuesday is limited.
Temperatures are forecast to be moderately cool for this time of
year with the amount of moisture present, and highs should be in the
70s, with perhaps lower 80s in south central SD zones.
.LONG TERM...(Tuesday night through Monday)
Issued at 339 PM CDT Mon Jun 25 2018
By mid week, an upper ridge of high pressure begins to redevelop
over the south central United States which will provide rising
heights for our area. There may possibly be a weak wave riding over
this ridge Wednesday night worth a few pops, but overall chances for
rainfall are real skittish until Saturday or Saturday night. This is
due to an upper trough of low pressure moving into the intermountain
west late this week, then toward the western plains on Saturday and
Saturday night. Saturday will feature an unstable southwest flow
aloft in our area, and the corresponding warm air advection should
help to kick off showers and thunderstorms. The storms should be
progressive however as the corresponding low level wind shift is
moving from west to east as the upper wave also moves eastward. So
at this time, this feature may not exacerbate the on going
flooding. With the building ridge, it will become quite warm and
humid, especially on Thursday and Friday where moist dew point
values will help to produce widespread heat index values in the 90s
to around 100 degrees.
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1049 PM CDT Mon Jun 25 2018
Scattered rain showers with isolated thunderstorms will be
possible during the early overnight hours. By daybreak Tuesday,
most showers are expected to end, with low cloud decks and patchy
fog over much of the region. Fog will dissipate during the
morning, and cloud decks will rise and decrease in coverage
during the day.
Area Forecast Discussion
National Weather Service Wilmington NC
1013 PM EDT Mon Jun 25 2018
A weak front will remain stalled over the area through Tuesday
before Atlantic high pressure rebuilds. Another front may drop
into the area Friday before dissipating.
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
As of 1000 PM Monday...After collaboration earlier with SPC, we
believe the low levels were overturned so strongly by earlier
convection that there is now insufficient energy for severe
thunderstorms overnight. Relatively steep lapse rates aloft
still exist and will probably fuel the continuation of showers
and thunderstorms, but the probability of future severe weather
has dipped below the threshold needed for a watch.
High PoPs (70-100 percent) remain in the forecast for the next
few hours, with gradually drying conditions overnight.
Discussion from 845 PM follows...
Another active afternoon and evening with widespread showers
and thunderstorms, feasting on boundary interactions and CAPE of
2000-3000 J/kg. Wind damage again appears to be the primary
severe weather mode as the only report of hail was dime size in
Columbus County around 700 pm.
Convection so far has been primarily surface based, but a
subtle increase in 900-650 mb westerly winds is advecting in a
hot airmass that was strongly heated across central and western
South Carolina all day. These relatively steep lapse rates
aloft now encountering our very moist low levels should maintain
elevated CAPE values of 1500-2000 J/kg through midnight. A
broken squall line moving across the Piedmont counties should
reach I-95 in the next 1-2 hours. Additional wind damage is
quite possible with these storms. HRRR trends have been toward
less of an organized severe potential as this activity moves on
toward the coast overnight, however as we saw last night steep
mid-level lapse rates seem to be a significant determining
factor in how tenacious convection will be to continue on after
The next challenge (besides more warnings coming up in the next
few hours) will be determine how long and for what areas to do
a local extension of the Severe Thunderstorm Watch. -TRA
Discussion from 300 PM follows...
A Severe Thunderstorm Watch is in effect for the entire area
until 10 PM tonight.
A cold front is currently moving south into the area. Based on
surface observations, it appears the location of the front as
of 4 PM is near the NC/SC border. Convection is currently being
driven in two different locations. The first is for the coastal
counties, due to the sea breeze moving inland. The second is
further inland, which is due to a mid-level impulse approaching
from the west. The expectation is for convection to increase for
both areas, with the inland convection becoming more dominant
as we head into the evening. There is plenty of instability in
place, especially with temperatures well into the 90s and dew
points in the lower 70s. SPC Mesoscale Analysis currently shows
MLCAPEs ~2,500 J/kg across the southernmost tier of the CWA.
MLCAPEs are forecasted to increase over the next few hours with
a band ~3,000 J/kg across the southernmost tier of the CWA and
along the coast. Low level lapse rates are steep, up to 8 C/km.
PWATs are also around 2". All of these and more will help
increase the convective potential over the upcoming hours. The
main threat will be damaging winds. But small hail will also be
possible. Heavy rain should also be expected in these storms.
Though, they appear to be moving at a decent rate, which will
help to limit the flooding potential. However, any training or
backbuilding of storms over the same locations would cause
issues. The POPs generally reflect the timing of multiple CAMs
and radar trends. The worst conditions are expected in the
evening, then improving as the bulk of activity moves offshore.
Though, remnant showers should persist well into the night,
especially for the coastal counties. Overnight lows will
generally range from 70-75 degrees.
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...A relatively active pattern is likely to
persist into Tuesday as a weak front remains stalled over
eastern NC while a series of upper shortwaves move through the
area. Somewhat drier, more stable air will shift in from the
north as surface high pressure builds down the Eastern Seaboard.
Better instability will exist across the SC Pee Dee region
which will be south of the front. We show 40-50% PoPs Tuesday
into Tuesday evening, diminishing Tuesday night as the greatest
upper vorticity energy moves southeast of the area. A marginal
severe threat will exist mainly along the NC/SC border and the
Pee Dee region where the best instability will exist. High temps
will be noticeably cooler given the weak cold air advection.
Temps will top out in the upper 80s with heat indices in the mid
to upper 90s.
Temperatures will gradually warm Wednesday through Thursday as
the upper ridge builds toward the eastern United States. Mainly
diurnal convection is expected each day with the sea breeze the
main driver, though weak shortwave energy could also drive some
convection. Heat indices may be back above Heat Advisory
criteria again on Thursday.
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 300 PM Monday...A large upper ridge will build over the
area Thursday night through Sunday before shifting east of the
area early next week. Hot and muggy conditions are expected
through Sunday, with the potential for Heat Advisories. Mainly
diurnal convection is anticipated each day. Slightly cooler
temps will occur Monday into Tuesday as stronger onshore flow
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 00Z...Convection is ongoing and rather chaotic at this time.
There will be outflows that will trigger new convection for the next
2-3 hours. Later tonight, a more organized area of convection will
move into the western CWA around 03Z, but will start to weaken by
06Z. Leaning on the HRRR model for this. Tuesday, mainly cloudy
skies with a mainly northerly wind. Post frontal stratus is expected.
Extended Outlook...Scattered showers and tstms will affect all
terminals Tuesday night. Brief period of MVFR ceilings possible at
NC terminals Tue night. Otherwise mainly VFR outside brief
restrictions in scattered showers/tstms.
NEAR TERM /THROUGH TONIGHT/...
As of 845 PM Monday...Winds are almost exclusively driven by
thunderstorm outflows at the moment. The overall synoptic wind
is southwest for areas south of Cape Fear, and more easterly
north of Cape Fear, as a weak front is attempting to settle
south along the coast. We likely won`t see these winds settle
down until several hours after thunderstorms dissipate late
tonight. Discussion from 300 PM follows...
A cold front will move south into the area, then stall over the
coastal waters. North of the front, expect light winds,
generally from the north. South of the front, expect light
winds, generally from the south. Seas will range from 2-3 ft.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...Brief period of E to NE flow over the NC
waters Tuesday into Tuesday night before Atlantic high pressure
rebuilds and flow becomes southerly.
LONG TERM /THURSDAY THROUGH FRIDAY/...
As of 300 PM Monday...SW flow Thursday into Thursday night,
becoming variable Friday as a weak front drops into the waters.
Area Forecast Discussion
National Weather Service Indianapolis IN
1151 PM EDT Mon Jun 25 2018
The AVIATION Section has been updated below.
Issued at 340 PM EDT Mon Jun 25 2018
Showers and thunderstorms will increase in coverage through midweek
as an upper low and associated surface wave track across the Great
Lakes. Once this feature passes on late Wednesday...drier conditions
will return with a transition to hotter and more humid conditions by
late week into the weekend as a broad upper ridge expands into the
.NEAR TERM /Rest of This Afternoon and Tonight/...
Issued at 340 PM EDT Mon Jun 25 2018
Back edge of the rain associated with the wave tracking east through
Kentucky continues to pull away from southeast counties this
afternoon. Additional showers have developed in the wake of this
system however across the southwest half of the forecast area. Obs
analysis is suggestive that a weak surface wave may be the culprit
and radar interpolation supports this with showers rotating slowly
counterclockwise. Clouds had encompassed much of the area and were
keeping temperatures down as a result. Most locations remained in
the 70s as of 19Z.
The primary focus right out of the gate is with the new shower
development which most model data is not handling well. Recent runs
of the HRRR are beginning to pick up on the feature. Should see a
gradual decrease in shower coverage over the next few hours as the
wave shifts east and narrow ridging aloft expands into the area by
early this evening. Will carry chance pops for the next few hours
over the southwest half of the forecast area to account for current
showers. With the instability gradient focused closer to the Ohio
River...do not anticipate any impacts from thunder through early
High pressure centered over the eastern Great Lakes continues to
maintain a dry easterly flow into parts of the region and is
effectively blocking the warm front draped from central Missouri
into western Kentucky from making any progression to the northeast.
That will hold for much of tonight as the high drifts slowly
southeast into New England. While chances for rain will begin to
slowly increase...still appears the bulk of more substantial
convection will largely remain southwest of the region overnight.
Expected convective development in association with another wave
aloft over eastern Missouri this evening is likely to track along
the instability gradient and dive southeast into the lower Ohio
Valley and eventually the Tennessee Valley. This is further
supported by a low level jetlet nose into western Kentucky and
Tennessee. CAMs hint at the lower Wabash Valley likely being clipped
again by this complex late this evening and will carry highest pops
in southwest counties.
Despite the dry easterly flow persisting through the lower levels
tonight...a vorticity lobe aloft ejecting out from the upper low
moving through the Missouri Valley will drift across the region
before weakening overnight and could produce isolated to scattered
convection focused primarily across the southwest half of the
forecast area. Will carry low chance pops to cover.
Temps...considering the cloud cover and potential for at least
isolated convection tonight...much prefer the warmer MAV guidance
for lows in the mid and upper 60s.
.SHORT TERM /Tuesday through Thursday/...
Issued at 340 PM EDT Mon Jun 25 2018
Forecast challenges continue to focus on an uptick in rain and storm
chances through late Wednesday before the transition to the hotter
and more humid pattern develops late in the short term and
especially beyond into the extended period.
The departure of the surface high off to the east will finally allow
the warm front to lift north through the region Tuesday and
introduce an influx of deeper moisture into the Ohio Valley.
Meanwhile...the aforementioned upper low over the Missouri Valley
will track E/NE into the Great Lakes by Wednesday. A surface wave
associated with the upper feature will track in tandem eventually
pulling a trailing cold front through the area on by late Wednesday.
The combination of these features will bring a steadily increasing
threat for showers and thunderstorms Tuesday and Wednesday...with
peak coverage and impacts likely to come Tuesday evening into
The combination of the warm front lifting north and increasing
diffluent flow aloft ahead of the upper low will promote convective
development Tuesday. The atmosphere at least initially on Tuesday
will only be weakly unstable as cloud cover is likely to hamper
heating. That will be enough for thunderstorm development but
overall intensity will likely remain subsevere into Tuesday
afternoon. Once the warm front lifts through the area however...
moisture and instability will increase going into Tuesday evening.
Mid and upper level flow will intensify as an upper jetlet wraps
around the front end of the low. Additionally...a 35-40kt low level
jet will expand across the area Tuesday night.
With both BL shear and helicity values increasing as the upper low
approaches in addition to what is mentioned above...the airmass will
become much more favorable for robust convection going into Tuesday
night. Some of the hi-res guidance seems to be favoring this
thinking with afternoon convection developing to the west of the
region and migrating into the area mainly after dark. Presence of
the enhanced flow at 850mb should maintain convection all night.
Sounding analysis indicated thermodynamic profiles are not
perfect...but certainly support potential for strong to severe
storms with convection Tuesday night. Precip water values near 2
inches and the 850mb jet still make heavy rain the primary threat
into Wednesday morning.
Scattered convection will persist on Wednesday but gradually
transition to the east into the afternoon as the front sweeps across
the area and the upper low and surface wave shift east. Will
maintain chance pops for much of the day but anticipate the entire
area will be dry by early evening. The remainder of the short term
will see the transition commence to the hotter and more humid
pattern set to encompass the Ohio Valley by late week into the
weekend. The ridge aloft centered over the southern Rockies will
expand east with heights aloft rising substantially from late
Wednesday through Thursday evening. The core of the ridge will build
into the area by Friday. High pressure will maintain dry weather
Wednesday night and Thursday. Some hints that central Indiana may
briefly align in northwest flow as the heights expand just
outside the short term Thursday night with the possibility for
convection riding along the ridge periphery. More on this in the
Long Term section.
Temps...have trimmed temps back a bit from previous forecasts
Tuesday as clouds and convection will likely keep highs primarily in
the lower to mid 80s. Low level thermals support gradually warming
temperatures for the rest of the short term with many areas
approaching or reaching 90 on Thursday. A model blend worked well
for overnight lows. Wednesday night may bring slightly cooler
weather as winds briefly turn northerly in wake of the frontal
passage Wednesday. Beyond that point however...all signs point to
lows primarily in the 70s going into the extended period.
.LONG TERM /Thursday night through Tuesday/...
Issued at 202 PM EDT Mon Jun 25 2018
Lack of model consensus will lead to a low confidence forecast for
much of the long term. That said, good confidence that an upper
ridge will reside over the Mississippi Valley Thursday night.
Central Indiana will be on the periphery of this ridge and fast
upper flow over the Great Lakes and Canada. This will mean central
Indiana will be in northwesterly flow and models suggest an MCS
could move in overnight Thursday night and or Friday from Iowa
and northern Illinois. Still, confidence is low enough that small
blend PoPs will be accepted.
After that, most of the weekend should be dry and warmer as the
upper high settles over the Ohio Valley and later northeastern
states. Prefer the GFS that is slower to move the ridge out to sea.
At any rate, by Sunday and especially next Monday, the ridge will be
suppressed with a few storms possible along the periphery of
southwest flow aloft.
Confidence in hot temperatures with highs in the 90s through most of
the weekend. With a soupy atmosphere, good chance we will see some
heat headlines for the weekend.
.AVIATION /Discussion for the 26/06Z TAF Issuance/...
Issued at 1147 PM EDT Mon Jun 25 2018
Showers and thunderstorms will overspread central Indiana from
southwest to northeast tonight due to an upper wave. Some MVFR
ceilings have been drifting into the area over the last hour, but
flight conditions should generally be at VFR levels outside of any
convection. Any showers and thunderstorms that do form though
could result in quick deterioration to MVFR or worse conditions.
Meanwhile, winds will generally be southeasterly at 5 to 10 kts.
Area Forecast Discussion
National Weather Service Jacksonville FL
902 PM EDT Mon Jun 25 2018
.UPDATE...Storms developed over central Ga this afternoon and now
are moving south across the Alatamaha River. Southeast Ga remains
moist and unstable enough to keep convection going...possibly
reaching near the Ga-Fl border this evening per the HRRR model.
Expect a weakening trend as instability slowly fades with
convection ending shortly after midnight. Isolated convection over
the Suwannee Valley of ne Fl with the seabreeze should wind down
.AVIATION...VFR conditions will prevail tonight through Tuesday
morning. Storms currently over se Ga may affect SSI mainly between
.MARINE... Southwest winds at 15 knots or less with afternoon sea
breezes forming near the coast Tuesday afternoon. Seas in 2-4 foot
Rip Currents: Low risk.
.PRELIMINARY POINT TEMPS/POPS...
AMG 74 94 74 93 / 50 40 20 30
SSI 78 89 78 90 / 40 40 10 30
JAX 75 94 75 93 / 10 30 10 40
SGJ 76 91 75 90 / 10 30 10 30
GNV 73 93 74 92 / 30 40 30 40
OCF 73 92 74 90 / 30 40 30 30
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
815 PM EDT Mon Jun 25 2018
Issued at 801 PM EDT MON JUN 25 2018
Rain dissipated quickly throughout the late afternoon and early
evening across eastern Kentucky. This led to an update of the pop
and weather grids, diminishing the pops quicker to match up
with the radar trends, and removing predominate thunder and heavy
rain wording. Even now, the scattered pops across the CWA are
probably too high, and will likely be lowered in the upcoming
update. In conjunction with the loss of rain, all urban/small
stream advisories and the flash flood warning were allowed to
expire on time. After coordinating with RLX, the flash flood watch
was also cancelled, since no other flooding threats are in place
for this evening.
Some of the hi-res models try to bring in a swath of something
between 6 and 8Z in the southern CWA, but it should have weakened
drastically by the time it reaches us, and only result in some
scattered showers. The HRRR also points at another round of
showers and maybe a rumble of thunder near dawn on Tuesday. Will
continue to monitor the model trends and update the overnight
forecast as necessary. Expect that this will likely lower pops
across the CWA for the overnight if any changes are made.
Finally, loaded the latest observations into the near term portion
of the forecast to make sure the temps, dew points, and winds
were on track with the current conditions. All updates have been
published and sent to NDFD/web. A new forecast package was also
sent out to remove the flood watch and heavy rainfall wording.
.SHORT TERM...(This evening through Tuesday night)
Issued at 430 PM EDT MON JUN 25 2018
20z sfc analysis shows a meso high moving through eastern
Kentucky in association with the last of the MCS induced showers
and thunderstorms. Many locations picked up several inches of rain
with the earlier rounds of convection and some localized flooding
remains possible with this latest batch for the southern parts of
the area. To the north, the heaviest rains fell earlier in the
day but there is another final batch of rain looking to develop
over north central Kentucky and then sliding east into the area
late this afternoon. In addition to the heavy rain, a few of the
storms produced damaging wind gusts with numerous reports of trees
down - again mainly across the southern parts of eastern
Kentucky. To deal with the ongoing, but waning, convection have
issued the zones with a pre-first period.
Currently, temperatures are in the low 70s with the rain areas
while they have rebounded into the low to mid 80s for the
southwest parts of the area. Dewpoints remain high with readings
in the upper 60s and lower 70s most places. Meanwhile, aside from
the storm related gusts, the winds have been light and variable.
Thanks to the storm clusters plenty of clouds remain, though
just now some clearing is starting to move into the western
The models are in fairly good agreement aloft through the short
term portion of the forecast. They all depict an MCV moving
through eastern Kentucky late this afternoon into the early
evening. Some ridging builds in briefly late tonight into Tuesday
morning ahead of a closed low trough moving out of the Central
Plains and into the Upper Midwest - heading into the Great Lakes
that night sending lower heights into Kentucky toward the end of
the short term. Given the mesoscale nature of the features
affecting the forecast in the near and short term have strongly
favored the higher resolution HRRR and NAM12 for details.
Sensible weather will feature showers and limited storms for
several more hours and then a threat for left over development
for a couple of hours beyond that and into the evening. The
boundary that helped to spawn the storms of last night and today
remains in place, though, so that a few additional storms and
showers will be possible towards dawn. Lingering boundaries and
the front starting to move back north looks to be enough for
additional storms generated by the sfc instability and falling
heights aloft. The weather would then settle well into the night
before the actual cold front approaches late with additional
showers and storms anticipated toward dawn Wednesday.
Started the grids with the CONSShort and ShortBlend making a few
adjustments for spot temperatures each night. Adjusted the PoPs,
as well, to linger the convection a bit longer into the evening
and then to add more of a diurnal component for Tuesday
.LONG TERM...(Wednesday through Monday)
Issued at 335 PM EDT MON JUN 25 2018
The models are very good agreement aloft through the extended
portion of the forecast. They all depict the departure of a decent
trough from the Great Lakes and Ohio Valley at the start of the
period. As it exits a fair amount of energy will trail behind
through Thursday. Strong ridging then builds northeast from the
Southern Plains into Kentucky through the end of the work week. By
the weekend this ridge will be right over Kentucky with its
suppressive effects in full swing. Only gradually will the core of
this ridge shift east through the area later in the weekend and to
start next week. Late in the period the ridge may be far enough east
that some mid level energy is able to approach from the northwest.
Given the excellent model agreement aloft confidence is rather high
in the blended model output for the extended portion of the forecast
- provided that it adheres to the tenants of strong ridging over
Sensible weather will feature another round or two of thunderstorms
associated with the unseasonably deep sfc low moving through the
Great Lakes with a cold front extended south through Kentucky on
Wednesday. This boundary should clear the CWA that night with left
over moisture and still some energy around aloft enough to keep a
small chance for convection in the forecast Thursday. High pressure
at the sfc and strong ridging aloft should then shut down convection
for the end of the week and into the weekend with mid level warmth
providing a hearty cap. Can`t rule out a late day storm in
southeast parts of the area on Sunday, but most places should stay
dry. Due to the ridge heat and humidity will build resulting in
heat indices around 100 degrees or higher through the weekend.
Will continue to highlight this in the HWO and social media
messaging. For Monday, the ridge will be off to the east allowing
more return flow and with less of a cap in place so that some
afternoon, diurnally driven, storms will be possible along with
not quite as oppressive heat and humidity.
As for temperatures in the extended, made mainly just some very
small terrain based and spot adjustments to the lows each night
with some increase with the highs for Friday through Sunday with
the ridge. Did not deviate far from the blended PoPs through
Thursday while emphasizing the diurnal trends. After that, dropped
the PoPs to sub 15% in accordance with the dominant capping 5h
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 814 PM EDT MON JUN 25 2018
Bit of an uncertain forecast. Heavy rains that swept through
eastern Kentucky earlier have since dissipated, but have left
abundant llvl moisture and low hanging clouds in their wake. As we
head into the overnight, wouldn`t be surprised if this moisture
leads to fog development, even with some clouds present. The
question is how much fog and what impacts will it have, especially
at the TAF sites. Kept TAF sites MVFR for VIS overnight, along
with continued IFR CIGS, but expect this to be variable and could
even be worse in some locations. Will update as we begin to see
the fog develop and it`s impacts overnight. Shower/thunderstorm
development is expected once again during the day tomorrow, with
generally MVFR CIGS. Exact timing/impacts of these showers and
thunderstorms is still unknown, so kept VFR VIS at this time.
Winds will be light and variable through the period, outside of
any thunderstorms that develop.
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1020 PM EDT Mon Jun 25 2018
A frontal boundary will be stalled just south of the area through
Wednesday with an area of low pressure moving along it. The low
and front will move northeast Thursday, and then another cold front
will move in from the northwest Friday. High pressure will build in
over the weekend.
.NEAR TERM /Overnight/...
As of 1020 PM Mon...A few showers/storms forming across SW zones
in association with outflow from earlier storms in SE NC, will
increase in coverage across E NC overnight as shortwave energy
rides ESE along stalled front and outflow boundary residing
across the southern zones. Should be fairly decent coverage of
precip, though not expecting much severe. With MLCAPE still
above around 1000 J/KG and effective shear +25kt, cannot rule
out an iso strong to severe storm with main threat a damaging
wind gust, though main threat overnight will be heavy rain and
Previous discussion... As of 730 PM Mon...Initial area of
thunderstorms staying mainly s and w of the FA. Main area of
interest continues to be MCS moving through Piedmont of NC, and
will likely move into the Coastal Plain around 10-11 PM, and
thus delayed higher pops until then. No other changes.
Previous discussion... As of 430 PM Monday...Based on latest
NAM and HRRR, increased POPs to likely to categorical over
southern 2/3 of area overnight.
As of 300 PM Monday...Cold front has stalled over Carteret and
Onslow counties where it has run into sea breeze. Only light
showers currently over northern sections but scattered storms
developing upstream and line of strong to severe storms moving
across mountains. Previous forecast update generally on track
with scattered activity next few hours, and then more widespread
activity moving in after 5 PM. HRRR continues to indicate lull
8-11 PM then line moving through into overnight hours. With
front stalled across southern sections, some potential for
strong to severe storms mainly this evening and highest along
and south of Hwy 70. Stuck with previous forecast of chance
north to likely south for POPs but may increase based on latest
radar and meso model trends at issuance time. QPF forecast will
indicate 0.5 to 1 inch amounts for southern half of area but
higher amounts likely with any repeating storms. Min temps
mainly low to mid 70s.
.SHORT TERM /TUESDAY/...
As of 330 PM Monday...Models in decent agreement that front
will be stalled just south and west of area with weak wave
development due to continued shortwave energy from W-NW. ECMWF
is a bit further north with shortwaves and then has wave lifting
into coastal plains allowing warm sector push back over SW half
of area during late afternoon. Leaned to GFS/NAM with
clouds/precip expected to keep front just to south. Will have
POPS from chance north to likely south with just a marginal
threat of strong to severe storms over extreme SW sections.
Clouds and onshore flow likely keeping max temps in lower 80s.
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
As of 435 am Monday... The cold front will be to the south of
the area with high pressure building into the area, while a weak
low is forecasted to develop along the frontal boundary to the
south...bringing rain across the area. High pressure will
rebuild into the region through early next week.
Tuesday night-Wednesday... The frontal boundary will be to the
south of the area, while a shortwave aloft moves along where the
boundary is located...resulting in a weak low developing.
Unfortunately, models are struggling with the development,
location and timing. Overall, expect cloudy and rainy conditions
Tuesday and lingering into Wednesday. Temperatures will be
cooler on Tuesday due to cloudy and rainy conditions, expect in
the low 80s Tue and increasing Wed to the mid 80s inland and low
Thursday-Monday... A mid to upper level shortwave will move
across the area Thursday resulting in additional
showers/thunderstorms. Then a weak cold front pushing through
Friday with high pressure building across the region afterward.
This will allow for diurnally driven scattered showers and
thunderstorms across the area for each day. Expect temperatures
to return back into the 90s inland and mid/upper 80s along the
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Short Term /through 18Z Tuesday/...
As of 730 PM Monday...VFR will prevail next few hours, then
periods of sub-VFR likely showers/tstms moving NW to SE over TAF
sites in the evening. Some storms could be severe with damaging
wind gusts mainly south of KPGV. Precip will diminish to
scattered to numerous showers overnight and continue into
Tuesday with front stalled south of area. NE-E flow expected to
result in MVFR CIGs developing overnight and continuing into Tue
morning as well.
Long Term /Tuesday night through Friday/...
As of 330 PM Monday...sub-VFR likely Tue night into early Wed,
then improving to VFR rest of period outside of mainly diurnal
showers and storms.
Short Term /through Tuesday/...
As of 330 PM Monday...Cold front has pushed to between Ocracoke
Inlet and Cape Lookout with N-NE winds around 10 KT to north and
SW 10 KT to S. Front expected to stall until late evening, and
then push south overnight aided by showers/storms moving through
from NW. Front will then stall south of area Tuesday with weak
low pressure development resulting in easterly flow around 15 KT
most of waters.
Seas 2-3 ft tonight will build to 3-4 ft Wednesday.
Long Term /Tuesday night through Friday/...
As of 415 AM Monday...Winds will veer to SE Tue night into Wed
and becoming S/SW 5-15 kt Thursday. Friday winds will briefly
become northernly as a weak frontal boundary pushes through most
of the area before winds veer back to the SE 5-10 knots late
Friday. Seas generally be 2 to 4 ft for most of the period,
except Wednesday where seas 3 to 5 ft.
Area Forecast Discussion
National Weather Service Paducah KY
724 PM CDT Mon Jun 25 2018
Issued at 724 PM CDT Mon Jun 25 2018
Updated aviation section for 00z TAF package.
UPDATE Issued at 555 PM CDT Mon Jun 25 2018
Minor adjustments to reflect slower initiation of convective
activity this afternoon and early this evening. Most of the
convection is starting to develop along the convergence
zone/instability axis running from Perry County Illinois to
Muhlenberg County Kentucky, with minor development over southeast
Missouri west of Ripley and Carter counties.
Although the severe potential remains, decided to remove severe
wording from the gridded and text forecast late this afternoon and
very early this evening due to the delay in upscale growth of
thunderstorms at this time.
Made some other minor PoP/Weather updates to reflect movement of
thunderstorms along the boundary later this evening and overnight.
.SHORT TERM...(Tonight through Wednesday night)
Issued at 243 PM CDT Mon Jun 25 2018
Satellite and surface observations continue to depict a slowly
shifting northwest to southeast surface boundary advecting
northeastward through the WFO PAH forecast area. At 1 pm CDT, LAPS
depicted the boundary from near Pinckneyville IL onward to Sturgis
and Greenville KY. Most of the towering cumulus is showing up
along the convergence zone, where surface CAPE`s are running
between 1500 j/kg to 2000 j/kg at 19z Monday. The highest CAPE
values (around 3500 j/kg) was noted along the MS river in
Mississippi Co. Missouri. The NAMNest is most similar in
suggesting convective potential into west Kentucky, while the
NAM12 and HRRR model runs are best representative of the
development of convection over southeast Missouri. May make a last
minute change to reflect a blend of these solutions.
The suggestion is that multicell storms that develop over the
foothills over southeast Missouri will congeal into a linear
mode/broken squall line this evening. Do not anticipate much
significant activity until after 21z (4 pm CDT) with the main
convective line exiting to the east around midnight or 1 am
Tuesday. The next round of showers and thunderstorms should expand
east across the area between 4 am and 10 am on Tuesday.
The lowest forecast confidence lies with the range of PoP
solutions for Tuesday afternoon and evening. Even SPC`s Day 2
Outlook is conditional on antecedent cloud cover and atmospheric
stabilization during this time period. At this time, the forecast
rain chances may be too high for Tuesday afternoon and evening as
compared to the 12km NAM-WRF solution. Anticipate the most
forecast changes in the next 12 hours will be with this time
Going into Tuesday night and Wednesday, the signal for pre-
frontal/frontal convergence and lift should lead to a transition
of PoP/Weather from west to east through Wednesday evening, as a
warm layer builds in with the ridge and caps the potential for
Heat index values should top out near 100 in the delta region of
southeast Missouri on Tuesday afternoon, with 100 to 105 degrees
expected over southeast Missouri and the Purchase area of west
Kentucky from late morning to late afternoon on Wednesday. The
exact coverage will depend on lingering cloud cover and
temperature recovery during the day.
.LONG TERM...(Thursday through Monday)
Issued at 243 PM CDT Mon Jun 25 2018
The primary concern during the long term period is heat. A
potentially high-impact heat wave is expected Thursday into the
weekend. The potential for increasing moisture later in the weekend
into early next week could blunt the heat wave beyond day 5, but
there is still some model variability at that time range.
A strong 500 mb high will build over the lower Ohio Valley on
Thursday, with the 594 dm center nearly overhead. This high is
likely to suppress convection and even cloudiness. A west-southwest
low level wind flow will advect hot air into our region, with 850 mb
temps climbing into the lower 20s Celsius. Surface highs will range
from the lower 90s in sw Indiana and the KY Pennyrile region to the
mid 90s further west. Heat indices near 110 are possible in the
The high will drift slowly eastward Friday through the weekend, then
become stationary over the Appalachian Mountains. The chance of an
isolated storm will slowly increase through the weekend. Subsidence
will decrease ever so gradually as our region becomes located on the
southwest periphery of the deep-layer high. Although forcing will be
very weak, the magnitude of the instability could drive some
isolated afternoon convection. The moisture will have little if any
impact on temps Friday, when highs will be in the mid 90s
everywhere. There could be a more noticeable impact by Sunday,
although heat indices are still forecast to exceed 100 degrees.
Early next week, the 500 mb high center will move off the Atlantic
coast. However, the southwest extension of the ridge axis will be
over the lower Ohio Valley. This ridge will be responsible for
persistently hot conditions, however it is possible that isolated to
scattered diurnally driven storms could blunt the impact of the
Issued at 724 PM CDT Mon Jun 25 2018
Isolated to scattered shra/tsra possible until around 07z,
especially at KEVV/KOWB, then again after 11z at all TAF sites,
but these times are current best estimates. VFR conditions will
be predominant through the TAF period, with brief MVFR conditions
possible in and near shra/tsra. Winds will be variable around 5
kts at KEVV/KOWB, and south at 4 to 9 kts at KCGI/KPAH.
Area Forecast Discussion
National Weather Service Blacksburg VA
1145 PM EDT Mon Jun 25 2018
A weak cold front will push south across our area and stall to our
south through tonight. High pressure aloft will then build over the
eastern U.S. during the later half of the week resulting in hotter
and humid conditions along with the threat of diurnally driven
showers and thunderstorms.
.NEAR TERM /THROUGH TUESDAY/...
As of 1145 PM EDT Monday...
Made some quick adjustments to existing forecast to increase
threat of precipitation across northern portion of forecast area
to account for expanding area of showers in isentropic zone.
This area a bit further north than higher resolution models
originally depicted...basically at point where depth of cool
pool and warm moist advection overrunning it reaches level of
free convection (LFC). Forecast soundings in this region show
only very shallow positive area, but one with some vertical
depth, so despite limited overall convective available potential
energy, showers breaking out along nw-se LFC axis.
Models suggest that slow southwestward trend may occur as the
night progresses as depth of cool pool forces LFC further to
the SW, so will maintain trend for higher threat of
precipitation slipping a bit SW with time per earlier forecast.
Otherwise, no changes needed at the present time.
As of 815 PM EDT Monday...
Made some changes to the near-term grids to reflect impact of
cooling associated with progressive line of showers and
thunderstorms that is now moving southeast and out of the
southern portion of the Blacksburg forecast area.
Although severe threat has ended, many of the higher resolution
models indicating that redevelopment of light showers across at
least the southwestern third of the forecast area is expected as
the night progresses as weak southwestern isentropic lift
returns on the backside of the departing mesoscale vorticity
complex (MCC) while the cool air wedging amplifies with
building surface high pressure to the north. This already well
reflected in the existing gridded forecast.
However, a more stratified environment with limited convective
positive positive energy in mid levels, and only lackluster warm
moist advection over deepening cool pool would argue that
overall rainfall amounts for the rest of the night will be on
the light side. Lighter precipitation amounts for the overnight
period reflected in 18Z NAM Nest, 21Z RAP, and 22Z HRRR models -
a far cry from the bullish convective maxima of the earlier
runs of the ECMWF and Canadian models - which did not at all
anticipate the extent of post-MCC stratification that now
resides over the Blacksburg forecast area. Will therefore lower
total amount of precipitation for the overnight period to about
half of what was earlier forecast - more in line with latest
Otherwise, rest of forecast still appears to be on track, so no
other noteworthy changes needed at the present time.
As of 308 PM EDT Monday...
A series of remnant Mesoscale Convective Vorticity Centers
(MCVs) will move from Kentucky toward our region around the
southwestern periphery of a midlevel trough over New England.
MCV over eastern Kentucky will travel east this afternoon into
tonight. SPC Mesoscale analysis at 18z showed that surface based
CAPEs have climb to 1to 2K J/kg and LIs are minus 1 to minus 3.
The best supercell composite parameter is to our west across
Kentucky and to our south in central North Carolina. With a weak
cold front pushing south across our area and stalling to our
south tonight. Expected scattered showers and thunderstorms to
develop this afternoon into tonight. SPC Day One convective
outlook has a slight risk across southwestern portions of the
forecast area. Multicell clusters will be the primary convective
mode, with the potential for wind damage with downbursts
through this evening as storms coalesce on outflows and move
Shaped pops this afternoon into tonight towards a blend of the HRRR
and NAM. As the main system passes by this evening, surface trough
moves further off shore and surface ridge becomes established with
high pressure setting up a warm-season wedge. In other words,
sagging frontal boundary becomes a wedge front Tuesday morning
with some upslope clouds, showers and patchy fog.
While some of the rain may be heavy with thunderstorms, rather high
flash flood guidance values and coverage precludes any need for a
watch at this point. Under cloudy skies, low temperatures tonight
will range from the upper 50s in the northwest mountains to the
upper 60s in the piedmont.
Wedge conditions should exist on Tuesday with easterly/southeast
convergent flow supporting greater coverage of clouds and showers in
the western mountains. Higher PWAT values will be transported
northwestward from the Carolinas. There is enough instability to
support some scattered thunderstorms especially in the west. The day
two convective outlook has posted a marginal risk for severe
thunderstorms on Tuesday near the frontal boundary and across the
higher terrain across southwest portions of our forecast area. The
main threat is potentially damaging wind gusts. High temperatures
Tuesday will vary from the upper 60s in the northwest mountains to
around 80 degrees in the piedmont.
Forecast confidence during this part of the forecast is
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 303 PM EDT Monday...
This portion of the forecast will be characterized as an active
weather pattern. An upper level shortwave trough will approach the
area Tuesday night into Wednesday, and then cross the region late
Wednesday afternoon and evening. Showers and thunderstorms are
expected during this entire time period with the best chances
Wednesday afternoon and evening associated with the passage of the
main trough axis and surface cold front. The latest Day 3 Convective
Outlook at SPC places a Marginal risk of severe weather across the
far western sections of the region, with damaging winds being the
By Thursday, the main trough axis will be to our east, but
precipitation chances will linger one final disturbance wraps into
the area on the backside of the main system. Look for primarily
isolated to scattered showers across western parts of the region.
Northwest flow downslope conditions east of the crest of the Blue
Ridge will limit any development there.
Temperatures during this portion of the forecast will trend milder
each day with readings a few degrees above normal by Thursday.
Forecast confidence during this part of the forecast is moderate to
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 1245 PM EDT Monday...
Thursday night into Friday will be the time frame where an upper
level ridge starts to build into the region. This feature is
expected to strengthen, broaden, and become centered over the area
by the the end of the weekend. The result will be increasing
heights/temperatures across the region. While not zero,
precipitation chances will be on the low side. and limited to a few
locations across the mountains where the combination of diurnal
heating and weak orographical influences may help fuel showers and
Heat index values are forecast to be in the low 100s both Saturday
and Sunday afternoon over parts of the Piedmont region.
On Monday, precipitation chances will increase a bit across mainly
western parts of the forecast area. The center of the upper ridge is
expected to shift east, and this in turn will help lessen the
strength of the capping inversion.
Temperatures during this portion of the forecast are expected to be
around five to ten degrees above normal.
Forecast confidence during this portion of the forecast is moderate
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
As of 815 PM EDT Monday...
Deepening cool moist wedge building southwest over the
Blacksburg forecast area as high pressure builds north of the
region will clash with warmer and more moist air that will be
lifted northeast over the cool pool - resulting in gradual
lowering of ceilings and visibilities over the entire Blacksburg
forecast area as the night progresses.
Most areas should experience IFR flight conditions well before
daybreak - and likely even as early as late evening/around
midnight from Bluefield to Blacksburg, and points south along
the eastern flanks of the Blue Ridge which experienced a soaking
rain earlier in the day. LIFR flight conditions with obscuration
of the higher ridges is likely along the eastern flanks of the
Blue Ridge by late tonight as upslope flow intensifies with cool
Also expect to see redevelopment of showers/light rain and even
some drizzle in upslope areas as the night progresses as warm
and moist air is lifted northeast over deepening cool pool.
Precipitation most likely along and southwest of a line from
Lewisburg through Roanoke to Danville.
The low level wedge expected to remain in place on Tuesday, and
despite drying aloft, expecting that sub-VFR ceilings will
likely persist for much of the day along with some added shower
coverage - especially in southern and western sections.
Medium confidence in ceilings, visibilities and winds during
the TAF period.
.Extended Aviation Discussion...
Low cigs likely to persist within the wedge Tuesday night with
sub-VFR conditions in spotty light rain or drizzle also possible.
The wedge should scour out on Wednesday as another low pressure
system arrives from the northwest with added showers and
stronger storms possible by Wednesday afternoon.
Strong high pressure will follow this feature for the end of
the week with widespread VFR expected outside of early morning
patchy valley fog and perhaps isolated storms across the
mountains Thursday into Friday. Outside of a few MVFR showers in
the southwest portion of the forecast area, VFR conditions
should prevail Saturday.
As of 155 PM EDT Monday...
The NOAA weather radio transmitter in Hinton, West Virginia that
is WXM72 and broadcasting at a frequency of 162.425 MHz is off
the air. Parts are on order to repair the transmitter, but there
is no known time of restoration. We apologize for any
Area Forecast Discussion
National Weather Service Las Vegas NV
240 PM PDT Mon Jun 25 2018
.SYNOPSIS...An area of high pressure over the Desert Southwest will
keep hot and dry conditions in place through Wednesday. A trough of
low pressure will move across the western states Thursday and Friday
leading to increasing southwest winds and temperatures pulling back
several degrees going into the weekend.
.SHORT TERM...through Wednesday night.
Little change in the weather can be expected through Tuesday night
and the most noteworthy concern will be fairly dense smoke over
northern Inyo and Esmeralda counties from the Lions Fire near
Mammoth. According to the HRRR Surface Smoke forecast, more diffuse
smoke will be observed over northwest San Bernardino County and also
portions for southern Nevada and northwest Arizona. However, it
should not be dense enough to mention in the forecast. Wednesday
will see a moderate increase in winds as the leading edge of an
incoming Eastern Pacific trough begins to influence the area. South-
southwest gusts of 25-30 mph will be fairly extensive. High and low
temperatures will stay fairly consistent before the downward trend
develop the latter half of the week.
.LONG TERM...Thursday through Monday.
The strong high pressure that will bring the above normal
temperatures early in the week will be shoved east as a trough
pushes into the west coast. This will bring a cooling trend that is
expected to last into the weekend. Temperatures are forecast to be
right around normal with little in the way of clouds. With the
approaching trough, southwest winds are forecast to increase
Thursday afternoon across much of the area. Most places will see
winds between 25-35 mph which will lead to fire weather concerns.
Winds will be lighter across the area Friday with the exception of
Mohave County where a few gusts over 30 mph will still be possible.
Winds will be lighter over the weekend as the area will be
sandwiched between high pressure off the coast and low pressure to
.AVIATION...For McCarran...Mostly clear conditions, except for some
diffuse smoke from distant wildfires, will continue through Tuesday
with high temperatures around 108-110. A south-southwest component
around 10 knots will occur in the evening and overnight hours. East-
southeast wind components occasionally gusting around 15 knots can
be expected during the afternoon hours.
For the rest of southern Nevada, northwest Arizona and southeast
California...Smoke from a wildfire in the Sierra Nevada will affect
flight visibility across Inyo County. Otherwise, no weather or
significant clouds expected. South to southwest winds around 20
knots during the afternoons, with lighter winds overnight. No
weather or significant clouds expected.
.FIRE WEATHER...Elevated fire weather conditions can be expected
by Wednesday afternoon as a Pacific Trough begins to move inland.
South-southwest gusts of 25 to 30 mph will be fairly extensive
across the region Wednesday afternoon with single digit relative
Critical Fire Weather conditions are a concern across much of
southern Nevada and northwest Arizona by Thursday afternoon as the
trough moves inland potentially leading to extensive gusty southwest
winds 30 to 40 mph.
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
SHORT TERM/AVIATION/Fire Weather...Adair
For more forecast information...see us on our webpage:
http://weather.gov/lasvegas or follow us on Facebook and Twitter