Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/08/20
Area Forecast Discussion
National Weather Service Amarillo TX
633 PM CDT Tue Jul 7 2020
.AVIATION...
Generally VFR conditions expected tonight and most of Wednesday,
with only a few shots at some storms. This evening, thunderstorms
have developed across the northeastern New Mexico plains, with a
few of them likely to make it within 10-20 miles of KDHT between
02Z and 04Z. There will be a bit of a wind shift from the storms,
but should generally remain VFR with high clouds / ceilings.
Storms should continue to diminish overnight, with not much in the
way of thunderstorm chances re-appearing in the afternoon or
evening hours. Pretty much expect a repeat of today for tomorrow`s
forecast, which means scattered storms developing in the far
northwest, only to diminish as the storms move south and east.
Fox
&&
.PREV DISCUSSION... /Issued 151 PM CDT Tue Jul 7 2020/
SHORT TERM...Today through Tomorrow Night...
Current 500mb RAP analysis shows the area of high pressure over
the SW CONUS with weak NE flow over the FA. A shortwave
disturbance will eject ahead of the main trough pattern that is
swinging across the NW CONUS. This shortwave will bring
westerlies aloft and be a dynamical forcing for storms off the
NM/CO mountains this afternoon into the evening. West northwest
flow aloft will continue through tomorrow with another potential
shortwave disturbance off the base of trough pattern pivoting with
an associated closed low in Canada. An axis of mid-level moisture
is present both today in the W FA and tomorrow in the E FA in
concordance with thunderstorm chances.
Thunderstorm chances have increased today in the W third of the
OK/TX Panhandles. Dewpoints are sitting in the upper 50s to lower
60s with an axis of 700mb theta-e setting up along the NM/TX
border. MUCAPE values are around 1000-1500 J/kg with 0-6km
effective shear around 25 to 30 knots around the time storms enter
the FA, which may be the driving factor to help keep storms
continuing a bit longer this evening. The storms will enter the
northwest portion of the combined Panhandles between 5-7 PM. All
the models agree that the storms are likely to create a
potentially strong outflow boundary with gusty winds. DCAPE values
are around 1500 J/kg, so as storms collapse there is a chance for
a severe wind gusts or two to come out of the storms. Storms are
expected to quickly diminish to potentially some light showers
around 10-11 PM.
Tomorrow the chance for storms return in the northeast Panhandles
for only a few hours in the evening. Another axis of 700mb theta-e
is present along with some surface moisture associated with a
potentially weak dryline setup. The NAM3k is the most aggressive
with initiating storms in the east, but the NBM also has been
trending PoPs higher into the 20s and 30s. The instability exists
with MUCAPE values of up to 2000 J/kg and shear of 30 to 40 knots.
If the NAM plays out and keeps the better moisture in the eastern
Panhandles for storms to initiate, then the main threats will be
similar to today with strong gusty winds.
Temperatures are continuing the warming trend with highs
remaining in the upper 80s to mid 90s today due east southeast
winds at the surface. Tomorrow winds will likely be more from the
south with highs getting back into the upper 90s to 107 range.
However, if winds tomorrow tend to take on a more southeast
direction for a majority of the day then that may be what keeps
temperatures just a few degrees cooler.
Rutt
LONG TERM...Thursday through Monday...
Upper high over the southern Rockies and southwestern states
Thursday of 590 to 593 dam will shifts a little further east
Friday and deepen to around 597 to 600 dam Friday. Further
intensification of the upper high expected this weekend with 598
to 600 dam before weakening slightly Sunday into early next week
around 594 to 598 dam. A cold front should push into the northern
Panhandles by Saturday morning and then slowly move southward
across the remainder of the forecast area by Saturday night and
early Sunday. Max temps only slightly lower Saturday, but will be
in the 101 to 110 this weekend into early next week with around
110 to 112 in the Palo Duro Canyon. Max temps Thursday and Friday
in the upper 90s and around 100 to around 110 to 111 in Palo Duro
Canyon. Will likely be needing a Heat Advisory or Excessive Heat
Warning between Thursday and Monday.
Schneider
FIRE WEATHER...Saturday through Monday...
Due to the hot temperatures and minimum afternoon relative
humidity values of around 10 to 15 percent, RFTIs of around 1 to 2
will be possible. Could possibly have some elevated fire weather
concerns this weekend into early next week, however 20 foot south
and southwesterly winds of 10 to 15 mph will mitigate the threat
and will be mainly relative humidity-driven elevated fire weather.
Schneider
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
$$
14/77
Area Forecast Discussion
National Weather Service Bismarck ND
1012 PM CDT Tue Jul 7 2020
.UPDATE...
Issued at 1010 PM CDT Tue Jul 7 2020
Severe threat continues over the area as strong thunderstorm wind
reports continue to pour in over western North Dakota. Expect this
to continue to push to the east.
UPDATE Issued at 800 PM CDT Tue Jul 7 2020
Severe Thunderstorm Watch number 340 has been issued for all of
western and much of central North Dakota until 200 AM CDT/100 AM
MDT. Multiple severe wind reports continue to come in over eastern
Montana as the line continues its approach.
UPDATE Issued at 647 PM CDT Tue Jul 7 2020
What was stated in the previous discussion continues to hold true
with the expected severe weather event tonight. Severe storms
continue to quickly race through eastern Montana, with the main
line producing 80+ mph wind gusts reports west and southwest of
Glasgow. The whole line continues to push east at around 50 to 60
mph and is currently pushing through Glasgow. A secondary area to
the south developed off the northern Bighorns, and also continues
to push towards the area. Models continue to have the low level
jet strengthening tonight ahead of system, sustaining the severe
convection.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 254 PM CDT Tue Jul 7 2020
Severe thunderstorms are likely tonight, with the possibility of a
significant, high-end damaging wind event, but with uncertainty in
the event`s overall magnitude due to midlevel capping.
At mid afternoon, mass-field responses are underway in response to
the strong middle- and upper-level shortwave trough approaching
central MT, with ~4 mb/3 hour surface pressure falls centered over
eastern MT and western ND. Resultant low-level southeast flow has
allowed surface dewpoints to rise into the lower and middle 60s F,
with additional moisture advection expected to yield MUCAPE on the
order of 2500-4000 J/kg from this evening into tonight in western
and central ND. The greatest bouyancy will be in southwestern and
south central ND, near a low- and midlevel warm frontal zone, with
relatively-richer moisture. Forecast soundings from several model
cores strongly suggest midlevel capping could be an issue tonight,
despite falling heights and DCVA aloft and its related cooling,
with CIN for both elevated and boundary-layer-based parcels of -50
to -150 J/kg possible, especially in the area of greatest CAPE.
However, even small boosts in boundary layer moisture -- perhaps
not much greater than that which is already ongoing based on
observed afternoon dewpoint trends -- may yield sufficiently-low
CIN for maintenance of organized convection moving into the state
from MT. Moreover, if sufficient clustering and upscale growth of
the MT convection occurs before it arrives, then well-established
cold pools may be sufficient for slab-type ascent through a deep
enough altitude to maintain organized MCS structures into central
ND, where capping could be strongest.
Thus, the magnitude of low-level moisture advection into southwest
and south central ND by early evening, and the degree of upscale
growth and strength of cold-pool-related ascent upstream by then,
will be key mesoscale components in determining the magnitude of
tonight`s event. Capping concerns aside, the parameter space will
be characterized by both large CAPE and strong wind fields with
deep-layer shear magnitudes of 50-60 kt, 0-3-km bulk shear on the
order of 30 kt, and low-level, 0-1-km SRH on the order of 200-400
m2/s2, all supportive of both organized bowing structures as well
as embedded yet persistent mesocyclones which could yield both an
enhanced risk of damaging winds of 80+ mph and tornadoes. Passage
of the strong shortwave trough is also indicative of a possible
higher-order, organized damaging wind risk.
GOES-East satellite imagery through 1945 UTC shows both increasing
convection near the cold frontal zone in central MT, and attempts
at convective initiation in the higher terrain of south central MT
and north central WY. This is in line with the well-clustered CAMs
including the 12 UTC HREF members and HRRR cycles through its 18
UTC iteration, which strongly support one or more storm complexes
reaching western ND in the 00-03 UTC time frame and central ND in
the 04-06 UTC time frame. Given the aforementioned parameter space
and balancing uncertainty of midlevel cap strength which itself is
apt to be regulated by low-level moisture advection, we believe
two primary outcomes could occur tonight:
1) Semi-organized complexes of storms with some embedded bowing
segments cross the area with occasional damaging winds and hail
risk, but with potential weakening with east and southeastward
extent due to midlevel capping, or
2) A well-organized, upscale-growing bowing MCS develops across
southwest ND and races northeast, with potential for a high-end
damaging wind event that could approach derecho scales within at
least a narrow corridor where the intense convection intercepts
rich low-level moisture with local weaknesses in capping near the
warm frontal zone, amid very strong low- and deep-layer shear. In
this scenario, QLCS spin-up tornadoes are also very possible, in
addition to larger-scale embedded-mesocyclone tornado risks. Note
that this scenario is highly conditional and uncertain due to the
potential for capping.
It is not yet clear which of the two scenarios will occur, with
some latitude for a scenario in between, with much dependent on
mesoscale details through early evening. Recent trends in CAMs
suggest the highest potential for outcome number two could be
along an axis from Bowman and Dickinson toward Center and
Washburn, where the 12 UTC HREF probability of UH >150 m2/s2
exceeds 50 percent. Again though, we need to message the risk
while bearing in mind capping could play a role in this event
moreso than perhaps earlier thought.
Regardless, storms are expected to quickly clear the area by about
09 UTC, with a drier, post-frontal westerly flow on Wednesday.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 254 PM CDT Tue Jul 7 2020
A drier period is on track Wednesday and Thursday with slightly
cooler temperatures as the region finds itself on the southern
flank of an upper-level low in southern Canada. Thereafter, the
subtropical ridge is forecast to strengthen south of the local
area, with increasing mean westerly flow to its north. The 12 UTC
global model suite suggests a shortwave passage centered on Friday
afternoon and Friday night will deliver the next round of possible
strong to severe storms, as supported by the CIPS Analog Severe
probabilities. Thereafter, NBM-based PoPs support a drier period
over the weekend, with some uptick in convective potential again
next week as the flow aloft may return to a southwest direction.
Highs Friday into next week are mainly forecast to be 85 to 95 F.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 647 PM CDT Tue Jul 7 2020
Strong to severe thunderstorms are likely beginning in western ND
around 01 UTC, and quickly moving into central ND by about 04
UTC. The storms could be severe with enhanced potential for
damaging surface winds of 50 kt or higher, along with local IFR or
LIFR conditions. The storms will move out of the area by 12 UTC
as a cold frontal passage occurs.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...JJS
Area Forecast Discussion
National Weather Service Dodge City KS
500 PM CDT Tue Jul 7 2020
...Updated Aviation...
.SHORT TERM...(This evening through Wednesday)
Issued at 333 PM CDT Tue Jul 7 2020
GOES 16 sat and mesonet data showing few to scattered cu field
around 6kt ft across southwest Kansas. Highs ought to top out in the
low to mid 90s this afternoon , with warmest temps in the 95-98 F
range over the western counties. The CAMs all generate clusters of
convection across eastern Colorado late this afternoon, and stall
out/decay the convection presumably from the very weak upper flow
aloft from the mid level ridge axis, before any storms are able to
enter western Kansas this evening. There could be a gust front
coming in from the west as well over the westernmost counties
depending on where the storm clusters dissipate, but threat from
thunderstorm wind gusts is extremely low. Beyond the evening, mild
overnight temperatures are expected area wide overnight, with upper
60s near the Colorado/Kansas line but around 70 degrees elsewhere.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 333 PM CDT Tue Jul 7 2020
For Wednesday, a dryline will move a little farther east, allowing
hotter temperatures, along with slightly decreased heat indices west
of the highway 23 corridor, while temperatures across the central
Kansas counties will be likely relegated to the upper 90s but very
humid as dew points remain in the mid to upper 60s from Wakeeney to
Dodge City and Meade and points eastward. The NMM right now is the
only model that allows convection along the dryline starting around
21 UTC (4 pm) west of Liberal and expanding north along the feature
through Garden City to near Scott City. None of the other CAM models
are allowing convection to develop at this point, but do all agree
on a large mcs developing over central Nebraska around the same
time. Therefore small chc pops are found across our northeast counties
Wednesday night. By Thursday evening the model signals are a
little more favorable for convection more directly impacting the
forecast area, as a weak nw flow shortwave is noted in the GFS/EC.
Convection could initiate in a couple of areas along a farther
east dryline, impacting the southeast counties as well as moving
in from northwest Kansas in the evening. Thunderstorms, whether
severe or not are not favorable in the far sw kansas counties
Thursday evening.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 500 PM CDT Tue Jul 7 2020
VFR/SKC will continue through this TAF cycle. Only expecting some
scattered cumulus in the afternoon, and cirrus anvil debris from
Colorado convection overnight. Convection ongoing in SE Colorado
as of 22z is forecast by HRRR to dissipate near EHA around 02z
Wed. Kept all TAFs dry with no mention of thunder. SE winds of
8-12 kts will prevail through sunrise Wednesday. After 15z Wed,
expect strong south winds at DDC/GCK/LBL, sustained near 20 kts
with gusts near 30 kts. South winds will be about 5 kts weaker at
HYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 99 72 100 / 0 0 10 10
GCK 69 102 68 99 / 0 0 10 10
EHA 68 103 67 101 / 10 0 0 0
LBL 69 105 69 103 / 0 0 0 0
HYS 71 95 69 95 / 0 10 20 20
P28 70 99 74 104 / 0 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Turner
Area Forecast Discussion
National Weather Service Des Moines IA
647 PM CDT Tue Jul 7 2020
.DISCUSSION.../Tonight through Tuesday/
Issued at 339 PM CDT Tue Jul 7 2020
Weak MCV moving across northeast Iowa with convection firing to the
east/northeast of the system. No thunderstorm development over the
southeast yet despite good instability and little convective
inhibition. The HRRR remains over zealous in that area as well
suggestion scattered thunderstorm development in that area already
by 19-20z. Still possible for a few storms over the next few hours
and given the lack of shear and DCAPE values over 1000 J/kg,
stronger updrafts could produce higher wind gusts and possibly
isolated hail. Generally quite weather overnight with no
precipitation with lows in the lower 70s.
Warmer air moves over Iowa on Wednesday as the thermal ridge moves
further east though the much warmer air will remain south and west
of the state into Nebraska and Kansas. The pressure gradient will be
increase over the past few days and will allow for breezier
conditions. Also, this should allow dew points to mix to a degree
and keep readings in the 70 degree range. Overall, temperatures
should be a few degrees warmer than today with dew points near to
slightly lower. Heat index values will be near 100 in places during
the afternoon. Several of the CAMS are suggesting a few
thunderstorms over southeast Iowa and while the area will be highly
unstable, the lack of a forcing mechanism should limit any
thunderstorm potential. Thunderstorms are expected to develop along
a frontal boundary over South Dakota and Nebraska then evolve into
an MCS as the low level jet increases in the evening. The most
likely scenario would have an MCS roll down the stronger instability
gradient near or just west of the Missouri River Valley and this
leaves a fair amount of uncertainty regarding precipitation chances
into central Iowa later Wednesday night into Thursday. Have lowered
pops some during this timeframe due to chances of being split,
however, precipitation chances are likely still too high.
A shift to northwest flow will occur following the early Thursday
system with large high developing across the southwest CONUS and a
long wave trough to the east. This will lead to slightly cooler
conditions Thursday and Friday. A system dropping through the
northwest flow will bring a chance for thunderstorms Friday night
into Saturday morning. Again, the confidence over placement remains
lower than average as the MCS could drive further to the west.
Otherwise, typical mid July weather this weekend and into next
week.
&&
.AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/
Issued at 646 PM CDT Tue Jul 7 2020
Confidence is fairly high in VFR conditions through the period,
with mainly a diurnal cumulus cycle. No precipitation is
anticipated with mainly southerly winds at non-impactful speeds.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
Small
DISCUSSION...Donavon
AVIATION...Small
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1155 PM EDT Tue Jul 7 2020
.AVIATION...
Nocturnal stability in control through the overnight period,
yielding simply some lingering pockets of higher based cloud cover.
Some potential for shallow MVFR level fog formation at one or
terminals during the pre-dawn hours, potential too limited to
highlight attm. Standard high based diurnal cu field emerges
Wednesday within existing hot/humid environment. This environment
will offer at least an isolated potential for late day showers and
thunderstorms, perhaps focused in the vicinity of the Detroit
corridor along advancing lake breeze activity.
DTW THRESHOLD PROBABILITIES...
* Low for thunderstorms Wednesday mid afternoon into the evening.
&&
.PREV DISCUSSION...
Issued at 337 PM EDT Tue Jul 7 2020
DISCUSSION...
Satellite this afternoon is showing a surface convergence zone along
Lake St Clair due to the lake breeze helping to initiate an
occasional isolated shower. The Saginaw valley has been the focal
point for numerous showers and thunderstorms thanks to the trailing
edge of the pre-frontal trough that crossed northern MI late this
morning. Gusty winds will be possible with these storms due to steep
low level lapse rates (around 9 C/km with the latest RAP analysis).
Updraft strength in the strongest cells have been sufficient for the
production of pea-sized hail as well. The Tri-Cities area and Thumb
will continue to see the bulk of convection this afternoon/evening
being closer to the main forcing out ahead of the cold front.
Scattered development across the rest of lower MI will continue
through the evening resulting mainly from daytime heating with
chances rapidly decreasing after sunset.
Upper level wave quickly transitions east into Quebec tonight into
early Wednesday morning pulling the weak cold front back north away
from the CWA. Upper level ridge immediately follows maintaining the
heat over SE MI for Wednesday. Airmass under this ridge is the same
that the region has experienced the past several days so expecting
more of the same. 850mb temps remain around 18C leading to another
day of mid-90`s and dewpoints in the mid-60`s. A few isolated
showers and storms are possible Wednesday afternoon bubbling up in
this hot, humid airmass but subsidence under the ridge in the mid-
levels will help to limit convective potential. Thursday the ridge
axis moves east of lower MI allowing for increased southerly flow in
the low- and mid-levels. This will further solidify heat and
humidity likely making Thursday the hottest day of this week.
Apparent temps will reach into the upper 90`s by Thursday afternoon.
Friday brings the best chance for widespread rain. Low pressure
moving across the central Plains into the northern Great Lakes will
drag a cold front across lower MI late in the day Friday. Still a
ways out but currently there looks to be the potential for moderate
instability with the latest model suite indicating MUCAPE around
1000J/kg, however, shear isn`t looking impressive yet for good storm
organization. Some uncertainties remain with timing as the GFS
continues to be quicker bringing the shortwave into the region by
Thursday whereas the Euro has been slower with the bulk of the rain
late Friday afternoon through the first half of Saturday. Post fropa
highs this weekend will only be in the mid to upper 80`s with a
slight reduction in dewpoints into the lower 60`s.
MARINE...
A weak cold front over southern Lake Huron will continue dropping
southward through this evening resulting in scattered thunderstorms
and brief wind gusts to around 35 knots. Winds will flip around to
the northwest behind the front this evening and will linger from the
north through the overnight while remaining fairly light. High
pressure will build back over the region Wednesday and will hold
through Thursday while drifting slowly east. This will bring about
the return of southwesterly flow. The area should stay dry after
this evening convection ends with the next chance of storms holding
off til Friday.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Heat Advisory until 8 AM EDT Wednesday for MIZ061-062-068>070-075-
076-083.
Excessive Heat Watch from 8 AM EDT Wednesday through Thursday
evening for MIZ061-062-068>070-075-076-083.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....MR
DISCUSSION...KDK
MARINE.......DRK
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1002 PM EDT Tue Jul 7 2020
.SYNOPSIS...
A low pressure system will slowly drift east across Georgia
and South Carolina today, then continue a slow track up along the
East Coast through the rest of the week. Rain chances will be in
store every day of the forecast period with drier air trying to work
into the area by Sunday. Better chances for rain will be in store
for the early part of next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Evening Update...Lowered PoPs across many areas as banding -shra has
dissipated or weakened sigfnt/ly across the FA. Will cancel FF.A
with this update as no flooding is occurring and no new hydro issues
are expected through the evening and overnight.
730 PM Update...No sigfnt changes made to the going fcst outside of
tweaking PoPs down based on ongoing metwatch. May drop FF.A before
expiration time as precip has not accumulated over the watch area,
nor are prolonged high rates or training cells anticipated thru the
evening.
500 PM Update...Rounds of showers and a few thunderstorms continue
to swing across the area this evening. Expect quickly reduced vsbys
to arnd a mile or less in the heavier showers as the column remains
quite moist with PWATs arnd 2 inches. Continuing to monitor the srn
Upstate and NE GA for possible flooding as antecedent conds remain
high, esp across Elbert Co.
As of 230 pm EDT: Banding and rates have generally been quite weak
within the remaining Flash Flood Watch area, with mainly light
precipitation over the past few hours. Nevertheless, the latest RAP
run and a few of the mesoscale models depict newly developed bands
trying to wrap west across the lower Piedmont, especially from
Greenwood to Abbeville, through the evening hours. Thus, will keep
the watch going from Elbert to Laurens, for at least a few more
hours, given that some localized 1 to 2 inch rain totals have
already occurred in this tier, and any new bands will be efficient
rain producers.
Otherwise, a leading wave of 500 mb vorticity will likely lift
northeast of the area through the early evening hours, while a
trailing vort lobe provides forcing through at least the late
evening hours, and possibly into the overnight. The main 850 mb
circulation center poised to cross the central Savannah River this
afternoon should reach northeast SC by daybreak Wednesday. This will
lead to a steady dropoff in overnight PoPs, with the best lingering
chances across the eastern half of the forecast area.
As the circulation moves to eastern NC through the day on Wednesday,
low-level flow will become more northerly. Even though profiles
remain moist, this should cut down on upslope flow and associated
PoPs. There could well be better instability with slightly warmer
temps, and low-level convergence and ridgetop triggering may lead to
more afternoon thunderstorms - which would be the primary producer
of any additional heavy rain/flooding threat. Temperatures will run
at least 5 degrees below climo for maxes on Wed.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 215 PM EDT Tuesday: The weak, broad area of low pressure will
remain over the general area as we move into the short term, slowly
pushing east through the period. Best moisture will remain along the
coast with the associated surface low, but with the upper weakness
and another approaching shortwave, still should see a diurnal trend
with pops through the period remaining generally above-climo. There
may be some concern with locally heavy rainfall in the mountains and
of course cannot rule out an isolated pulse severe storm...support
seems slightly better for this on Friday with the approach of the
secondary upper trough. Temps will remain fairly close to seasonal
normals, though slightly warmer on Friday than Thursday. However,
with the plentiful low-level moisture around, could start seeing
some heat index issues Friday, as current forecast is starting to
bring some >100 degree HIs into the Upstate Friday afternoon.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 200 PM EDT Tuesday: The overall pattern in the extended
forecast is very well agreed upon between the global models. An
upper trough is expected to impact the area during the forecast
period. This should keep the tropical low on a northeasterly track
as it should be well off the Carolina coastline by the extended
forecast period. The upper trough will dig in from the Midwest and
eventually the Ohio River Valley Friday night into Saturday. An
attached frontal boundary will allow for scattered activity to
persist ahead of the boundary with any tropical moisture that`s
still hanging around in the area until the frontal passage takes
place between 18Z Saturday and 00Z Sunday. Drier air should filter
in during the second half of the weekend with temperatures expected
to be slightly above climo. As we move into Sunday and the early
part of the new work week, the upper trough will take its time to
pull out of the region and help increase PoPs, especially Monday
into Tuesday as diurnal activity will get a boost from the upper
level lifting and destabilization from surface heating. Temperatures
will remain at or slightly above climo through the rest of the
forecast period. Southwesterly flow and a low-level moisture flux
allows for higher PWAT values to return as most of the cwa will be
>1.50" during that time frame. An active pattern may be in store
for the region during the first half of next week.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Tricky TAF set with lingering bands of precip
sweeping across the region. These shower bands have lowered VSBY to
IFR or lower at times and have been hard to fcst or time into a
specific location. Anyway...have generally lowering precip chances
overnight due to loss of heating and lowering CIGs to MVFR most
locales except IFR CIGS at KAVL, KCLT and KHKY before daybreak. Slowly
improving flight conds in the morning to MVFR/VFR arnd mid day. Have
included a PROB30 TSRA Wed afternoon all locales as better insol
will make for higher instability than has been the case recently.
Winds will remain e/ly to ne/ly outside the mtns and nw/ly at KAVL
during the afternoon. Low end gusts are possible as well.
Outlook: A return to more diurnal afternoon and evening showers and
thunderstorms is expected late this week through the weekend. This
will mean mainly MVFR restrictions under any showers and storms, and
then morning IFR to MVFR cigs/visibility possible around daybreak
each day, especially in the river valleys.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 90% High 95% High 82% High 100%
KGSP Med 67% High 93% High 86% High 100%
KAVL Med 78% Low 57% Med 79% High 100%
KHKY High 84% High 85% Med 65% High 100%
KGMU Med 77% High 87% High 97% High 100%
KAND Med 67% Med 78% High 86% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables are available at
the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...CAC
NEAR TERM...HG/SBK
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...SBK
Area Forecast Discussion
National Weather Service Marquette MI
732 PM EDT Tue Jul 7 2020
.SHORT TERM...(This evening through Wednesday)
Issued at 303 PM EDT TUE JUL 7 2020
Uffda, more warm weather across Upper Michigan today and another hot
one expected tomorrow for most of the UP. As of 18Z, GOES imagery
depicts generally sunny skies with some diurnal cu developing around
4kft. Can see the developing lake breezes clearly in the cu field
movement, as Lake Superior`s is winning the race, but Lake
Michigan`s is starting to push inland now. These lake breezes will
be the focus for any potential thunderstorm development this
afternoon into this evening. CAMs still are showing a few isolated
thunderstorms to develop across central UP as the two lake breezes
enhance convergence. This added convergence will be needed for any
thunderstorms to develop as model soundings have been consistently
showing a slight capping inversion with latest RAP showing 500 to
800 J/kg and 35 kts bulk shear. With that, no widespread svr storms
expected, but as with any lake breeze thunderstorm there is a chance
for some smaller hail and gusty winds if any cell can ride along the
lake breeze long enough to develop before the core falls back down.
Tonight, lows were a little tricky as a weak ridge of sfc high
pressure did bring in some drier air across the west half of the UP
today, lowering PWATs; however, as an increase in SW winds begins
across the west tonight, PWATs and WAA increase. Ultimately brought
lows up a degree or two, but still expecting interior west to fall
into the mid to upper 50s, near 60 across the east, and low 60s
along Lake Superior.
Tomorrow, mid-level ridging increases as SW flow continues to bring
an increase in WAA and moisture across the UP. To the west across
Saskatchewan, a closed mid-level low will remain nearly stationary,
slowly shifting east through the rest of the week as a shrtwv and
sfc trough extends to the south through the Dakotas. With the trough
remaining off to the west tomorrow, increased flow PVA and WAA will
bring a chance of showers and thunderstorms across western Lake
Superior, but have generally left any PoPs out of the forecast over
the land for now per 12Z CAMs. There may be a shower or two that
squeaks in across the west in the morning as a nocturnal complex
dies out moving through Duluth, and then again in the evening as a
complex of thunderstorms develops across MN and travels over Lake
Superior into Upper Michigan. Regardless, its going to be HOT
tomorrow with heat indices pushing into the mid 90s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 302 PM EDT TUE JUL 7 2020
Upper air pattern consists of a 500 mb ridge across the upper Great
Lakes with a shortwave over the northern plains 00z Thu. This
shortwave moves into the upper Great Lakes Wed night into Thu. This
shortwave moves into the lower Great Lakes on Fri. Deeper moisture
and 850-500 mb q-vector convergence moves in for Wed night through
Thu before moving out on Fri across the west, but lingering across
the east half of the cwa. Overall, did not make too many changes to
the going forecast.
In the extended, the GFS and ECMWF show a 500 mb trough across the
ern U.S. and a ridge across the Rockies 12z Sat. The ridge moves to
the east into the northern plains 12z Sun and into the upper Great
Lakes 12z Mon. A shortwave moves into the northern Rockies 12z Tue
and into the northern plains late on Tue. Temperatures will stay
above normal for this forecast period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 731 PM EDT TUE JUL 7 2020
VFR conditions will continue through most of the forecast. Dewpoints
have recovered a bit at KSAW and are approaching the mid 60s this
evening, which is close to where the were this AM when fog developed
there. KCMX is also in a similar situation with dewpoints in the
lower 60s. Main difference is that neither site is expected to
receive any precipitation overnight. While there is less confidence
in fog development at those sites tonight despite the mostly clear
skies, light winds and abundant low-level moisture, it remains a
possibility, so have included a brief period of fog late tonight. A
bit more confident at KIWD with fog development there, thanks to
local influences and have brought in lower ceilings and visibilities
at that site for a time late tonight. Once we get into the daylight
hours VFR conditions return. The next challenge is the timing of
convection at the western TAF sites...and at this time only expect a
very slight chance of convection at KIWD by late in the forecast.
Have left mention of showers and thunderstorms out for now, but this
will be included in the latter part of the forecast for the 06Z
package.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 303 PM EDT TUE JUL 7 2020
Under a continued warm and moist airmass, Lake Superior will
continue to see patchy fog, locally dense at times, throughout the
forecast period. These chances will increase if any precipitation
moves over the lake. There will be some thunderstorms moving over
western Lake Superior early on Wednesday and then again on Wednesday
night. There may be a few gusts up to 20 knots or so tomorrow from
the ESE, otherwise winds are expected to remain blo 20 knots through
the fcst period.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JAW
LONG TERM...07
AVIATION...RJT
MARINE...JAW
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
945 PM EDT Tue Jul 7 2020
.SYNOPSIS...
Low pressure will slowly drift east toward the Georgia-South
Carolina coast tonight along a stationary front that extends east
through Alabama, Georgia and central South Carolina. The area of low
pressure will slowly drift northeast across the eastern Carolinas on
Wednesday and Thursday. A trailing cold front will linger across the
Carolinas into the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 945 PM Tuesday...
01Z surface analysis shows the surface low WNW of Savannah, tracking
E before it turns up the Carolina coast tomorrow. Earlier showers
and isolated storms really diminished after 21Z, with only a couple
areas of light showers near Winston-Salem and Fayetteville, with
more but still scattered radar returns over NE SC. Even as the low
begins to track a little more north, the low-level ENE flow is
rather light, so there shouldn`t be much shower coverage overnight
outside of the southern coastal plain and perhaps in the western
Piedmont where isentropic/terrain upglide is a little better. Low
clouds should expand across the area after midnight, and pockets of
fog can`t ruled out (noted by HRRR in the Piedmont). Lows in the
lower 70s.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 245 PM Tuesday...
The surface low will be near the coast of SC by Wednesday morning,
with the boundary extending northeast along the NC coast and west
through GA. The low is expected to sit over the SC coast through
Wednesday night, possibly drifting slowly east-northeast to just
offshore by Thursday morning. The axis of highest rainfall chances
and amounts will be along the NC coast, with northerly flow on the
back side of the low resulting in a bit drier weather over much of
the Piedmont. The question will be how far west the boundary
migrates during the day, with some models suggesting it could nose
into the Triangle area. Best instability will generally be along and
east of I-95 Wednesday afternoon but shear will be limited. The SPC
has central NC in just general thunder. Showers and isolated
thunderstorms will likely develop during the aft and die off again
after sunset. Highs will again be below normal, generally in the low
to mid 80s with lows around 70 degrees, give or take a few degrees.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 157 PM Tuesday...
The weak upper low will slide offshore on Thursday, although an
elongated trailing trough will remain in place across central NC
Thursday into Friday. Despite anomalously high PW values above 2
inches area-wide, mid level moisture transport is largely
unimpressive over land Thursday and Friday with the highest values
displaced well offshore. While there will be a continued chance of
mainly diurnal precip to close out the week, the heaviest showers
should remain east of the forecast area.
As soon as the aforementioned low moves offshore, another longwave
trough and associated surface cold front will move through the
Appalachians Saturday into Sunday. What happens to the southern end
of this longwave trough has been the source of struggle among the
deterministic models the past few days, and today`s model runs still
depict varying solutions. The EC cuts off a weak low overhead Monday
and Tuesday whereas the GFS advertises a somewhat drier solution but
with a stalled front nearby. Probabilistic guidance and NBM suggest
at least a mention of precip early next week and this seems
reasonable at this lead time. Depending on how things evolve
synoptically, modest mid level flow in the vicinity of a stalled
upper low could result in a convectively favorable (potentially
severe) environment early next week but it`s still too early to have
much confidence in this time period.
As for temps, look for below normal highs Thursday, recovering
Friday and Saturday, followed by a slight post-frontal retreat
Sunday into next week due to elevated precip chances and post-
frontal airmass. Overnight lows will remain near normal throughout
in the lower 70s.
&&
.AVIATION /00Z TUESDAY THROUGH SUNDAY/...
As of 745 PM Tuesday...
24 hour TAF period: Somewhat of a persistence forecast as a surface
low migrates across central SC to the NC/SC coastal border area
tonight and moist ESE flow continues across central NC. Earlier
showers and very isolated storms have diminished. and most sites
will be dry overnight, with ceilings falling to MVFR (perhaps IFR at
FAY) after 06Z. A few showers may move inland toward FAY after 08Z
as the low tracks toward MYR.
Expect showers to again increase across central NC by midday
Wednesday as the low moves slowly up the NC coast, with mostly VFR
conditions, briefly dropping to MVFR is heavier showers.
Looking ahead: Periods of showers and sub-VFR will continue into
Thursday as the surface low tracks slowly up the NC coast. Improving
conditions are expected Friday into the weekend.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...KC/Blaes
NEAR TERM...bls
SHORT TERM...KC
LONG TERM...Leins
AVIATION..bls
Area Forecast Discussion
National Weather Service Reno NV
228 PM PDT Tue Jul 7 2020
.SYNOPSIS...
A dry weather pattern will continue this week with daily zephyr
breezes and seasonably warm temperatures. Smoke impacts can be
expected near the Numbers Fire. A slight increase in wind early
next week could lead to critical fire weather conditions.
Thunderstorms are possible over the mountains this weekend into
next week, however coverage appears spotty.
&&
.DISCUSSION...
* Gradual warming the next few days as a series of troughs coming
out of the Pac NW counteract the Four Corners heat ridge
attempting to establish itself. Peak temperatures appear to be
Friday through Monday, per NBM guidance, however only about 3-6
degrees above normal. Not too bad considering we`re in the
climatological peak of impactful heatwaves.
* With these passing troughs there is potential for stronger
zephyr winds at times but simulations continue to be somewhat
scattered on which days could bring more
fire/transport/recreation impacts. Right now Saturday-Monday has
the best chance. In any event it would be merely a "zephyr+"
type situation, but with super dry airmass and vegetation that
would be enough for another round of critical fire weather
conditions one or more of those days.
* Dry airmass will keep t-storms at bay through this week.
Starting this weekend some of the probabilistic guidance
suggests chances for mountain t-storms but odds are pretty
skimpy. Mainly Mono- Mineral Counties and east of Lassen Peak -
the typical hot spots. It`s not really until next week that
precipitable water values rise enough for meaningful t-storm
chances.
-Chris
&&
.AVIATION...
* Pretty quiet on the aviation weather front much of this week.
Zonal flow aloft leading to typical afternoon and early evening
westerly breezes. Gusts generally at or below 25 kts.
* One exception is smoke and haze from the Numbers Fire SE of
MEV. Assuming continued fire activity, which seems like a safe
bet looking out the window, HRRR smoke model shows good
potential for MVFR conditions at MEV and possibly HTH tonight
into Wednesday morning. Smoke will transport east/southeast from
the fire in the afternoon and evening, and then settle in to
the valleys late at night. Radar showing plume lofting to about
20,000 feet before spreading out to the east.
-Chris
&&
.FIRE WEATHER...
...Dry and Breezy Conditions Through This Week...
Very dry airmass remains in place through the week with humidity
in the teens and single digits. Poor overnight recovery is
expected each night as well, especially in the thermal belts.
Typical afternoon and evening zephyr breezes will occur each day
this week and into the weekend, with gusts up to 20-30 mph.
For the ongoing Numbers Fire near Gardnerville, these dry and
breezy conditions will continue through this evening, then
diminish overnight with heavy smoke draining into the Carson
Valley and Mason Valley. Dry conditions will be present overnight
for the Numbers Fire, as the Pine Nut Mountains are a known
thermal belt in our region. Also, as the fire continues to move
into the higher elevations of the Pine Nuts, winds will remain
breezy until around midnight.
Instability is good today, although a capping inversion around
15k ft will keep the plume from reaching great heights. As the sun
sets this evening, we will see the atmosphere become more stable
overnight. There is a bit more instability Wednesday as a weak
shortwave trough passes through Northern California, bringing
steeper lapse rates aloft and increase our Haines Index to 5. This
could lead to larger plume development if the fire continues to
align with fuels and topography.
We should remain in dry southwest flow through the weekend.
Chances for thunderstorms are looking less likely for early next
week, although there is a possibility that we could see a stronger
shortwave and increasing gusty winds around Monday. -Hoon
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Springfield MO
603 PM CDT Tue Jul 7 2020
...Updated 00Z Aviation Discussion...
.SHORT TERM...(This evening through Wednesday)
Issued at 211 PM CDT Tue Jul 7 2020
A nice cumulus field has developed across the area this afternoon,
with updrafts achieving both better height and coverage than
previous days. At 500 mb, a broad ridge has helped dampen
thunderstorm activity. Still, the convective environment is
favorable enough to support scattered showers and thunderstorms
through late afternoon. This environment has been characterized by
little CIN, adequate instability (1000-2000 J/kg MLCAPE), and just
enough mid- and upper-level moisture for updrafts to punch through
the LFC. While we are not anticipating any severe storms, the RAP
is suggesting Theta-e differentials between 20-25 K. This may
result in a few stronger updrafts with 40-50 MPH downburst winds
and penny- sized hail. Otherwise, the primary hazards with this
activity will be occasional cloud-to-ground lightning and heavy
downpours that will result in poor visibility.
Any showers and storms that develop this afternoon will quickly
dissipate near sunset. Temperatures tonight will cool to 70
degrees.
For Wednesday, the afternoon convective environment will be less
favorable, and coverage will be more isolated. This will be due to
dry air entrainment and less moisture in the mid- and upper-
levels. There will also be less instability around on Wednesday
with MLCAPE values between 500-1000 J/kg. The net effect will be
poor updraft growth, and fewer showers and thunderstorms.
Temperatures on Wednesday will warm to near 90 with overnight
lows around 70.
.LONG TERM...(Thursday through Tuesday)
Issued at 211 PM CDT Tue Jul 7 2020
The pattern changes by mid-to-late week as the 500- mb ridge
becomes more amplified. This will place the Ozarks on the eastern
periphery of the ridge as upper flow veers west- northwest. As
multiple shortwaves ripple through the Central Plains and round
the top of the ridge axis, a parade of MCSs will dig south out of
Nebraska and Kansas. The first of these thunderstorm complexes
will approach the region early Thursday morning along the MUCAPE
gradient/Theta-e ridge. With the axis of the LLJ displaced across
central Kansas, the thunderstorm complex will likely dissipate
early Thursday morning as it moves into far eastern Kansas and
western Missouri, perhaps leaving behind an MCV that could spark
additional convective activity Thursday afternoon/evening.
Temperatures on Thursday will again be near 90 with overnight lows
near 70.
By Thursday evening, another 500-mb shortwave should aid in the
development of another MCS across Nebraska. The latest runs of
the NBM and deterministic models (GFS, ECMWF, CMC) exhibit higher PoPs
for Thursday night and early Friday morning as the MCS glides
down the MUCAPE gradient and into our region. This will likely be
our next best shot of widespread rain across the region. This
nocturnal MCS has the potential to go severe. While the LLJ will
remain modest across our western cwfa, CAPE/shear profiles will
remain adequate/balanced enough for straight-line wind potential.
Additionally, high PWATS (+1.75 inches) should result in very
heavy downpours and frequent lightning.
The Friday through Sunday timeframe will remain hot as the
periphery of a closed 594-mb high builds across our western cwfa.
Daily temperatures will range from the low-to-mid 90s, with heat
index values between 100-105 F. Afternoon thunderstorm chances
will likely be held down by strong capping, but nighttime MCS
potential will remain possible, especially Saturday night into
early Sunday as yet another shortwave digs south into the region.
With so many MCS/MCVs floating across the region late this week
and into the weekend, temperature forecasts have big bust
potential. Nonetheless, a Heat Advisory (Heat Index values of 105
F) cannot be ruled out for parts of eastern Kansas and far
western Missouri this weekend.
The pattern looks very hot and dry by next week as that 594-mb
closed high builds closer to the Four States region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 603 PM CDT Tue Jul 7 2020
VFR conditions will continue into the evening and overnight hours
across the TAF sites. A few fair weather cumulus will linger
through the early evening hours with bases around 5 kft, before
dissipating and leaving behind clear skies. Meanwhile, surface
winds will remain light out of the east/southeast through the
overnight hours. Isolated showers and thunderstorms will return
tomorrow afternoon, but will remain very limited in coverage.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Albano
LONG TERM...Albano
AVIATION...Perez