Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/04/17
Area Forecast Discussion
National Weather Service Bismarck ND
945 PM CDT Mon Jul 3 2017
.UPDATE...
Issued at 926 PM CDT Mon Jul 3 2017
Weak convection trying to hold on over central ND from around
Garrison to Beulah/Hazen and near Hettinger. Isolated convection
can not be ruled out through the overnight hours as weak shortwave
energy traverses the area with a modest low level jet. Updated
pops and sky cover based on latest radar and satellite. We did
bump up lows a bit given the slow drop this evening and quick
recovery of dewpoints from afternoon minimums.
UPDATE Issued at 619 PM CDT Mon Jul 3 2017
A few thunderstorms continue across western North Dakota in an
an area of weak MLCAPE and marginal shear. Indications are that
convection will diminish if it even makes it into central ND this
evening. Made some minor adjustments to pare down pops this
evening due to the current lack of areal coverage. Otherwise no
significant changes other than updating latest sensible weather
elements and interpolating to mid evening values.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 255 PM CDT Mon Jul 3 2017
The highlight of the short term forecast will be a hot July 4th
holiday, with highs of 95 to 100 degrees F in many areas.
As of 19 UTC, southerly low-level flow is maintaining an axis of
middle and upper 50s F dewpoints across western ND in the vicinity
of a weak quasi-stationary frontal zone. Given the shallow nature
of the low-level moisture plume, and deepening vertical mixing, we
expect this moisture to be redistributed through the atmospheric
column by late afternoon with a corresponding drop in dewpoints at
the surface. However, forecast soundings from the 12 UTC NAM and
GFS and more recent RAP and HRRR cycles support 500 to 1000 J/kg
of MLCAPE in western ND through early evening, which is sufficient
for a few thunderstorms in the face of weak capping. The absence
of significant large-scale forcing, and perhaps more importantly,
weak, but broad and ongoing mid-level height rises, both suggest
that the coverage of convection will be relatively limited. That
being said, today`s suite of Convection-Allowing Models (CAMs)
support isolated to scattered showers and thunderstorms forming in
western ND by 21 UTC and propagating eastward through the evening.
The appearance of a weak, and subtle shortwave trough in GOES-16
preliminary, non-operational moisture channel images in eastern MT
as of early afternoon further builds confidence in the scenario
simulated by those CAMs since it could indeed foster a bit of
background support for deep, moist convection.
The presence of weak deep-layer shear (0-6-km and effective bulk
wind differences less than 25 kt) and modest bouyancy both argue
against a severe risk through this evening, though the presence of
steep low- and mid-level lapse rates could foster a strong storm.
The presence of mid-level height rises and lack of greater large-
scale forcing for ascent both suggest the convection should wane
as it reaches central ND by late evening, similar to last night.
On Independence Day, a strong low- and mid-level thermal ridge is
forecast to build across southwest and central ND in advance of a
slightly stronger vorticity maximum aloft and a corresponding low-
level frontal zone. Forecast 850 mb temperatures peak in the 25 to
28 C range, supportive of surface temperatures well into the mid
and upper 90s F. Given dry soils and deep vertical mixing, we do
believe some locations in southwest and south central ND will hit
100 F. Most past 100 degree days at Bismarck have been associated
with 850 mb temperatures in the 26 to 29 C range, so depending on
the eastward extent of the core of warmest mid-level temperatures
we could reach the century mark locally, as well. Interestingly,
the city of Bismarck has only reached 100 F on Independence Day
two times in the historical record, the last being in 1989. In
fact, we`ve only exceeded 95 F four times, so July 4th, 2017, is
forecast to go down as one of the top-five hottest Independence
Days in Bismarck regardless of whether or not we reach 100 F.
Once again, a few thunderstorms are possible in the late afternoon
and evening hours Tuesday, mainly along and east of an approaching
cool front and perhaps moreso along a pre-frontal wind shift that
may extend from Rugby to Bismarck/Mandan and Hettinger based on a
consensus of the 12 UTC global and CAM suites. Low-level moisture
and thus instability is forecast to be greater on Tuesday ahead of
that pre-frontal wind shift than prior days with late-day surface
dewpoints potentially remaining in the upper 50s or even lower 60s
F in support of MLCAPE of 2000 to 2500 J/kg. Deep-layer wind shear
is again forecast to be weak through both the 0-6-km and effective
layers with bulk wind differences less than 20 kt in south central
ND where convective initiation is initially expected thanks to the
intense heating of the boundary layer. The degree of CAPE and some
veering of the winds with height supports potential for isolated
severe multicellular convection with both a hail and wind threat,
though. As convection propagates to the east by Tuesday evening,
slightly stronger mid-level winds are forecast in the James River
valley and may result in a bit greater organization or longevity
to any storms that do initiate.
.LONG TERM...(Tuesday night through Monday)
Issued at 255 PM CDT Mon Jul 3 2017
Above-average temperatures are generally expected the next week
and beyond, but the hottest weather may come Wednesday and again
early next week, with somewhat cooler temperatures in between.
A strong subtropical ridge centered over the four-corners region
will be the prominent synoptic-scale feature in this period. The
local area will reside on the northeast side of that ridge, and
that in turn may allow backdoor cool fronts to press southward
into the region from time to time. That idea has been advertised
by global models for days, but more recent GFS and ECMWF cycles
have been a bit more prominent with the southward extent of late-
week frontal surges into the area and therefore the multi-model
consensus we used to drive the forecast suggests highs by Friday
ranging from only 75 at Rolla to 85 at Bismarck and 87 at Bowman.
Even so, it`s worth noting that the last few GFS operational runs
have been on the cool side of its ensemble and our dry soils may
tend to yield a cool bias in guidance, so it`s possible that our
forecast may not be quite warm enough at times. Moreover, there`s
still agreement in the global model suite for a flattening of the
subtropical ridge early next week, which may turn our flow aloft
more westerly, yielding another even hotter period then. Odds of
thunderstorms in this pattern are non-zero, but any convection is
apt to be spotty and in general driven by subtle waves which have
low predictability at longer lead times.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 926 PM CDT Mon Jul 3 2017
Isolated convection across western ND currently not close enough
to include a VCTS at either KISN or KDIK, and not expected to make
it to KMOT or KBIS. Will monitor but no mention of thunder tonight
at any TAF location. VFR ceilings expected through the period. A
cold front will move through the area Tuesday bringing a shift in
winds from southeast ahead to northwest behind the front. Isolated
to scattered convection is possible along the front Tuesday
afternoon. For now included a vcsh at KJMS late Tuesday afternoon.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...TWH
Area Forecast Discussion
National Weather Service Burlington VT
1052 PM EDT Mon Jul 3 2017
.SYNOPSIS...
High pressure moving into the region will keep a dry airmass
across the region through Wednesday. Temperatures will continue
to be seasonable for early July. Then, the chance of showers
and storms increases for Thursday through the end of the week.
&&
.NEAR TERM /UNTIL 6 PM TUESDAY EVENING/...
As of 1049 PM EDT Monday...very quick refresh of the forecast
grids late this evening just based on latest trends. those
isolated showers in northern NY are pretty much gone now. clear
skies are allowing some locations to start to cool off pretty
quick. I`ll admit, capturing all those localized details is
pretty hard, but I tried my best. Still expecting patchy fog to
develop over the next 2-3 hours.
Looks like everything is setting up for a spectacular July 4th.
Hope you can enjoy it.
Previous discussion from 730pm follows...
a few tweaks for the early evening update based upon latest
satellite and radar trends. A few showers have developed across
Ontario and into portions of northern NY, primarily out in the
St Lawrence Valley. This is in response to a weak shortwave
moving east-southeast across eastern Ontario interacting with a
little surge of mid-level moisture (both plainly visible on
GOES-16 mid-level water vapor imagery) and tapping some weak
surface instability (about 300 J/kg). Could be an isolated flash
of lightning, but for the most part these showers aren`t
expected to expand much beyond what they are right now. Relied
on HRRR and BTV 4km hi-res models to show the evolution in the
hourly PoP grids. Basically have a few spots of <30% chance of
showers for a few hours this evening across southern St Lawrence
and Franklin Counties.
Otherwise, skies will generally become clear in most areas,
though some clouds from up in Quebec may come down into the
northeast Kingdom. With high pressure building in, winds will be
light. So temperatures should cool off fairly decently. Boundary
layer moisture is plentiful and, patchy fog is expected to
develop, especially across northern New York, where temperatures
are forecast to drop several degrees below the cross-over
temperature (which is the lowest dewpoint during the afternoon).
Have continued the the patchy fog mention in the forecast as a
result.
Tomorrow should be similar to today, but perhaps slightly
cooler as cooler air oozes down from Canada on the northwest
flow. Convective allowing hi-res models do hint that there
could be a spot shower or two during the afternoon, but suspect
it will end up being primarily afternoon cumulus cloud buildups,
especially across the higher terrain with nothing more than a
sprinkle. PoPs are thus less than 15%.
&&
.SHORT TERM /6 PM TUESDAY EVENING THROUGH WEDNESDAY NIGHT/...
As of 332 PM EDT Monday...High pressure will continue to push
east toward the Gulf of Maine by Wednesday night. As it does,
return flow around the back side of the high will start to
transport a warmer and more moist airmass back into the region.
Expect increasing clouds across the region Wednesday night,
with the reintroduction of a threat of showers across portions
of New York.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 315 PM EDT Monday...The threat for showers with embedded
thunderstorms increases on Thursday into the weekend. Still
some large disagreements between gfs/ecmwf on placement of sfc
low pres and front...along with axis of heaviest qpf for Friday
into Saturday...resulting in lower than average forecaster
confidence.
On Thursday...1000 to 500mb moisture increases on developing
southwest flow aloft ahead of approaching s/w trof. This moisture
advection will help to increase pws to 1.50 by 00z Friday with some
weak surface based instability of 500 j/kg of cape across the SLV.
This moisture/lift and instability will help in the development of
scattered aftn/evening showers with embedded storms. However...the
lack of significant instability and weak deep layer
shear...expecting just embedded rumbles of thunder at this
time...with qpf generally under 0.25. The uncertainty develops on
Friday associated with short wave energy and weak low pres ejecting
from central Plains convection and potential interaction with
northern stream trof/energy. GFS is currently the most aggressive
with showing a secondary axis of moderate qpf from eastern dacks
into vt between 06-12z Friday with values between 0.50 and 1.25.
Based on the lack of significant forcing from upper level jet and
convective looking bullseyes in the qpf fields...thinking this is
overdone...will continue to mention chance/low likely pops and
monitor potential for heavy rainfall.
On Friday aftn into Saturday...additional energy and moisture
develops as mid/upper level trof and associated surface low pres
impacts the ne conus. Extremely difficult to pin point the exact
placement of heaviest qpf associated with track of surface low
pres/boundary with large spread in guidance. 12z GFS shows axis from
central ny into central vt...while 12 ecwmf is suppressed much
further south across central PA into southern New England. A close
investigation of low level jet axis and associated omega/qpf
bullseyes...I believe the gfs is suffering from convective feedback
issues and looks unreliable for this forecast, especially the qpf
fields. Soundings indicating plenty of clouds with deep rh
profiles....resulting in limited surface heating/instability...with
pws approaching 1.75". The threat for additional localized heavy
rainfall will needed to be watched...especially given saturated
ground conditions from previous events. Will continue to mention
high chc/low likely pops for Friday aftn into Saturday...before
system lifts and drier weather returns for Sunday.
925mb to 850mb thermal profiles suggest highs in the mid 70s to
lower 80s Thursday with progged 850mb temps near 12c. Little change
in thermal profiles expected Fri/Sat...but more clouds will limit
surface heating with highs mainly 70s with lows 60s and some return
to higher humidity levels likely by Friday. 850mb temps remain
between 11-13c for Sunday with better mixing supporting highs back
into the mid 70s to lower 80s.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...Aviation concern tonight is fog/br
development and potential ifr/lifr conditions at slk/mpv.
Current radar shows isolated showers across southern Saint
Lawrence County into the western dacks...which should dissipate
as they quickly move east by 04z. The combination of clearing
skies...light boundary layer winds...and temps falling 5 to 7
degrees below cross over values at slk should lead to fog
development between 04-06z. Have tempo ifr until 06z...then
placed prevailing lifr with vis 1/2sm ovc 100 feet until 11z. A
little more uncertainty at mpv as temps only briefly fall below
cross over values and clouds/winds are slowly to dissipate...so
have continued to tempo ifr conditions between 07-11z. A few
brief 10 to 15 minute windows of ifr possible at mss btwn
08-11z too. Elsewhere...vfr conditions prevail with light
northwest winds of 2 to 5 knots. Tuesday vfr expected with light
northwest winds 4 to 8 knots.
Outlook...
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. Slight Chance SHRA.
Thursday: VFR. Chance SHRA.
Thursday Night: VFR. Chance SHRA...Slight Chance TSRA.
Friday: VFR. Likely SHRA.
Friday Night: VFR. Likely SHRA.
Saturday: VFR. Chance SHRA...Slight Chance TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...JK
NEAR TERM...Nash
SHORT TERM...JK
LONG TERM...Taber
AVIATION...Taber
Area Forecast Discussion
National Weather Service State College PA
1143 PM EDT Mon Jul 3 2017
.SYNOPSIS...
A weak cold front will push south across the state this
evening. For Independence Day, high pressure will build to our
north while the front stalls along or just south of the Mason-
Dixon line. The second half of the week will be unsettled. A
cold front will pass early in the weekend and dry things out.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
The hard to find frontal boundary is settling south through the
Central Mountains, judging by the RAP LI fields and surface
dewpoint plots. Widely scattered showers continue in the
slightly more unstable air over the southern half of the CWA.
The HRRR gradually kills off the few showers we have now as we
enter the wee hours. i lowered POPs into the slight chance
range given the latest radar trends and diminishing CAPE being
observed as the sun begins to set.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Latest ensembles show the potential for about the southern half
of the state to see a shower on Independence Day, being closest
to the stalled boundary this seems reasonable. Hard to imagine
enough rain to ruin outdoor plans totally, but it does seem
likely a few locations will get wet before fireworks go off
tomorrow evening.
Highs will range from the mid 70s north to mid 80s south, which
will be a degree or two either side of normal. Dewpoints will be
in the comfortable range over about the northern half of the
forecast area. A little more noticeable or even uncomfortable
over the southern tier counties.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
The mid to long range models have a similar pattern and timing
until Friday. Generally zonal flow with subsidence due to higher
pressure will be across the region as a quasi stationary
boundary remains across the southern most portion of the
commonwealth. A weak trough moves to the northeast as a weak
ridge will build over central Canada. This is in contrast to a
trough that should continue to deepen over the southern midwest.
That trough should form a low that will make its way through
the central United States and reach the region by this weekend.
The biggest questions in the forecast is in regarding to the
timing and evolution of the system. The GEFS speeds up the
trough where the EC deepens the trough. This also coincides with
a secondary trough moving through the upper Great Lakes. The EC
slows the timing of the trough moving through the Great Lakes,
though it is also drier. So late this week there should be
successive storm systems that will move through the region, the
question is when. The strong moist southwesterly flow Thursday
and Friday should allow for a greater chance for afternoon
convection with Friday into Friday night being the best
timeframe. The cold front moving from the north could move
through Friday night into Saturday and while dynamics could
allow for storms, it would obviously be not diurnally favorable.
Behind that front and corresponding trough, dry, cooler
northwesterly flow should move into the region Saturday into
Sunday. As far as temperatures are concerned the ensembles all
seem to have a similar patter through the mid to long range. The
national blend is a little on the extreme early next week.
Overall temperatures should be around normal for the next few
days and then a cooler and drier period through the second half
of the week and through the weekend.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
A dying cold front will slide slowly south across the region
overnight, accompanied by isolated showers, which could
potentially produce a brief vis reduction at airfields over the
southern half of the state until 06Z-09Z. Main concern overnight
will be the potential of fog development, primarily across the
northwest corner of the state. Based latest observations and
satellite trends, feel the odds of significant (IFR) reductions
are about 25 pct at KBFD and KAOO, 10 pct at KUNV/KLNS/KJST and
near zero elsewhere.
Any early fog should burn off by around 13Z, with widespread VFR
conditions for the rest of the day. However, scattered afternoon
thunderstorms will likely form in the vicinity of stalled
frontal boundary across southern Pa. Therefore, can`t rule out a
brief reduction at the southern airfields.
.OUTLOOK...
Wed...AM low cigs possible JST/AOO.
Thu...AM low cigs possible.
Fri...AM low cigs possible. PM tsra impacts possible.
Sat...No sig wx expected.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Ross/La Corte
NEAR TERM...Ross/La Corte
SHORT TERM...Ross/La Corte
LONG TERM...Ceru/Martin
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Dodge City KS
1102 PM CDT Mon Jul 3 2017
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
Issued at 1100 PM CDT Mon Jul 3 2017
An upper level shortwave trough of low pressure is moving eastward
across the Central Plains. Meanwhile, an upper level ridge of high
pressure is building across the Intermountain West. Near the surface,
a lee side trough of low pressure extends from southeast Colorado into
western Oklahoma.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 256 PM CDT Mon Jul 3 2017
Warm front has lifted a bit further north into west central Kansas,
as noted in the weak reflectivity extending from near Syracuse-
Garden-Dodge and through Greensburg into south central Kansas. Based
on the convective allowing models interpretations, the more
scattered to numerous severe convective storms this evening should
be primarily confined to the warm front region and warm sector,
across south central Kansas counties and into western Oklahoma. The
severe parameters are supportive of an enhanced convective wind
threat and marginal threat for large hail. Tornado risk is
negligible short of a brief spinup. HRRR continues to show a
secondary broken line of storms moving into western Kansas from in
the later evening hours, but has become somewhat an outlier of the
numerical models.
No significant change in overnight temperatures, again mild in the
60. Tuesday may be somewhat influenced by leftover widespread
outflow across the area, light and variable winds and no obviously
discernible convergence zone for lift.
.LONG TERM...(Tuesday night through Monday)
Issued at 256 PM CDT Mon Jul 3 2017
Thunderstorm opportunities Tuesday night are likely relegated to the
extreme west, based on higher terrain upslope surface flow
convection to move into west central KS. Similar overnight
temperatures in the mid 60s are forecast for the overnight and
Wednesday morning. ECMWF develops a large ridge across the
intermountain west which persists through the end of the forecast
period, which is not a conducive setup for widespread severe. Highs
are likely to remain in the 90s with lows in the mid and upper 60s
through this period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 629 PM CDT Mon Jul 3 2017
A cluster of thunderstorms will continue south and southeast of
Dodge City early this evening. Radar and surface observations at
23z indicating multiple outflow boundaries from these storms in
the Liberal and Dodge City area so winds at these locations are
expected to be variable but primarily from the east at around 15
knots for the next few hours. As these storms move into Oklahoma
early tonight winds across western Kansas will become south
southeast at 10 to 15 knots. The RAP and NAM this evening both
suggesting some low status/fog possible between 09z and 15z
Tuesday at Dodge, Garden, and possibly even Liberal. Based on
model soundings this moist layer appears shallow so am leaning
towards mainly MVFR visibilities in fog. Otherwise VFR conditions
can be expected.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 62 92 65 92 / 30 10 20 10
GCK 61 93 63 94 / 50 10 20 10
EHA 59 95 63 94 / 40 10 20 10
LBL 62 95 65 94 / 30 10 20 10
HYS 64 91 65 91 / 30 10 20 10
P28 67 90 66 91 / 100 20 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJohnson
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Burgert
Area Forecast Discussion
National Weather Service Sioux Falls SD
1052 PM CDT Mon Jul 3 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 347 PM CDT Mon Jul 3 2017
The main concern for the short term is the prospect for
thunderstorms with heavy rain tonight and again into Tuesday
afternoon.
Current satellite shows lots of cumulus south of a SPW to MHE line
which likely depicts where the deeper moisture is located. Dew
points in this area are 65 to 70 with upper 50s along Hwy 14.
Moisture will continue to transport north on 10-20 kt flow between
925 mb and 850 mb. The wave that looks like it will enhance
convective development is in western South Dakota and Nebraska.
This wave is expected to reach the Missouri River in central South
Dakota by 00Z. As expected with relatively weak forcing in an
unstable environment, hi-res models show convection develop around
sunset but where that convection develops has varied throughout
the day. The most consistent signal from the NMM, ARW and NAMnest
has been in the James Valley north of Mitchell. The HRRR
originally favored this solution as well but has shifted north in
models runs since 16Z. At this time, have favored the larger
consensus and have convection developing in the James Valley
around 02Z and then moving east southeast to Sioux Falls and
Brookings around midnight and finally to the Jackson, MN and
Okoboji area of Iowa toward 12Z. South of this area there is a
much lower chance of rain. The upper flow is very week and with
southwest flow favoring new cell development on the southwest
flank of the MCS, the overall propagation of the system will be
rather slow. So there is the potential for locally heavy rainfall.
Considered a flash flood watch but with the uncertainty on where
storms will develop have decided to wait and see where convection
develops and if it will cover a large enough area to produce heavy
rainfall.
On Tuesday, model uncertainty continues as high res models have
varied from keeping all convection east of I29 and north of Hwy 18
to convection developing in the James Valley with the approach of
a second wave. Certainly, assuming an organized MCS develops,showers
could continue through the morning into early afternoon in parts
of southwest Minnesota and northwest Iowa as SSW flow at 850 mb
would overrun any outflow boundary. However, with higher
uncertainty, have PoPs gradually decrease to 30-40 percent.
Otherwise, have favored solutions that have convection develop in
the James Valley with the second wave during the afternoon. As
this wave slowly move east through the afternoon, the chance for
storms will spread toward I29 in the late afternoon and into
southwest Minnesota and northwest Iowa after 00Z Wednesday. Again,
if storms grow upscale, the MCS will only slowly move east so
kept 30-50 percent PoPs through Tuesday night.
Temperatures will be highly dependent on cloud cover and rain.
With expected cloud cover and dew points in the mid 60s, kept lows
in the mid 60s. Highs on Tuesday will range from around 80 in
southwest MN to the lower to mid 90s in south central SD.
.LONG TERM...(Tuesday night through Monday)
Issued at 347 PM CDT Mon Jul 3 2017
For Tuesday night through Monday, the primary concern will be
convection on Tuesday night and then heat Wednesday and Thursday.
As note above, any convection on Tuesday afternoon will only
slowly move east through the night. In fact with the wave still
near I-29 at 12Z on Wednesday, could see isolated showers or
thunderstorms continue into Wednesday afternoon around Hwy 71 in
northwest Iowa. Any rain that does fall should be short lived and
not really impact temperatures. Very warm temperatures will move
into areas west of I29 with highs in the low to mid 90s along and
west of the James River with upper 80s along I-29. Fortunately,
where temperatures will be warmest, afternoon mixing will lower
dew points into the upper 50s. East of the James River, where
temperatures will be a little cooler, dew points will be in the
upper 60s. With ample moisture and some wind, lows on Wednesday
night will be around 70. Thursday will be another very warm day -
as warm or warmer than Wednesday. Flow will have a westerly
component through the day - first from the southwest and then as
the front move through from the northwest. The frontal passage
will have little impact on temperatures during the afternoon - in
fact it could enhance mixing. So expect highs to be in the 90s
across the region. And with dew points again 65-70, it will feel
like it is in the mid to upper 90s. Despite the frontal passage,
rainfall is unlikely as there is a strong cap in place as the
front goes through. Also the frontal timing is rather poor for
convection as the front is expected to be near the Missouri River
by 18Z and south of Sioux City by 00Z Friday. Should the front
slow more, then there will be a small chance for convection
although the cap would still inhibit convection.
For Friday through Monday, temperatures are expected to be cooler
and be near normal. The ridge axis remains to the west through
00Z Tuesday. The GFS and ECMWF are markedly different by late in
the weekend with the strength of the upper low in eastern Canada.
The GFS appears over amplified with a 554 cutoff north of Lake
Huron by 12Z Monday. The ECMWF is much farther north with a
broader ridge which brings warm air back in by Monday. The ECMWF
has had a bias of bringing in warm air too quickly this summer so
a slower warm up seems more likely at this time. Both models do
have weak waves moving through the area on Saturday night and have
a low PoP for thunderstorms that night.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1046 PM CDT Mon Jul 3 2017
There could be patchy fog around the area early Tuesday morning,
possibly most prevalent at Sioux City. But otherwise VFR is
anticipated for much of the TAF period through Tuesday evening.
The biggest challenge for the 06Z TAFs is TSRA chances. There is a
weak upper level low which is moving very slowly eastward across
the plains tonight and Independence Day. The latest data based off
of 00Z is showing only very skittish activity through the TAF
period, too isolated to warrant a mention in the TAF sites in the
Sioux Falls forecast area at this time.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...Schumacher
LONG TERM...Schumacher
AVIATION...MJ
Area Forecast Discussion
National Weather Service Goodland KS
526 PM MDT Mon Jul 3 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 128 PM MDT Mon Jul 3 2017
Another weather disturbance embedded within northwest flow aloft is
forecast to emerge over the northeastern plains of Colorado
including Yuma south through Kit Carson counties. Isolated showers
and thunderstorms are initially expected with a gradual increase
in coverage and possible intensity this evening as it moves east
across the area. Another possibility is similar to last night with
showers/thunderstorms moving southeast from central Nebraska.
HRRR suggesting wind gusts in the 50 to 60 mph range so for now
have added gusty winds to the grids. Precipitation should be out
of the area shortly after midnight. Low temperatures in the mid
50s to mid 60s.
For Tuesday am expecting plenty of sunshine by mid to late morning.
Models suggesting another weather disturbance moving into the
western 2/3 of the area a little sooner compared to the past few
days with a few thunderstorms possible generally from McCook to
Tribune/Leoti and points west by 00z Wednesday. Afternoon
temperatures expected to reach the upper 80s to low 90s.
.LONG TERM...(Tuesday night through Monday)
Issued at 128 PM MDT Mon Jul 3 2017
Shower and thunderstorm chances continue into Tuesday night from the
afternoon as a weak shortwave moves east of the region. Height rises
to the west should hinder convection, but cannot rule out a few
thunderstorms. Severe weather will be possible generally north of
Interstate 70 with large hail and damaging winds as the main
threats.
An upper ridge over the western CONUS expands north and east on
Wednesday and Thursday, keeping the area under north northwest flow
aloft. High pressure dominates the pattern, resulting in dry
conditions during this timeframe. However, guidance has introduced a
quick shot at precipitation Thursday night into Friday as a
disturbance rotates around the eastern edge of the high pressure.
A backdoor cold front approaches the High Plains on Friday, stalling
across the region for the weekend. Meanwhile, the ridge to the west
flattens/regresses and the area is placed under northwest flow
aloft, allowing disturbances to work their way across the region.
This setup enables patchy shower and thunderstorm chances to return
to the forecast through the end of the period. It`s a bit too soon
to tell the timing and location of the waves passing through the
eastern periphery of the ridge, so will have to monitor in the
coming days and refine the forecast.
High temperatures will be in the upper 80s to upper 90s throughout
the period. However, a few locations along the Nebraska border could
see temperatures near 100 degrees on Thursday. Low temperatures will
be in the upper 50s to upper 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 526 PM MDT Mon Jul 3 2017
VFR conditions should prevail at KGLD and KMCK terminals, and
prevailing winds should remain below 12kt through the TAF period.
Thunderstorm activity over eastern Colorado is expected to impact
KGLD, with less confidence at KMCK. Temporary restrictions to vis
3-6sm, gusty winds, and possibly hail could accompany this
activity. Current guidance favors this activity decreasing in
coverage near KGLD and sliding south-southeast with less coverage
in SW Nebraska. Adjustments were made to reflect these trends.
Some guidance is showing potential for stratus/fog in north
central Kansas by 12Z, but even if this were to occur it is shown
to remain well southeast of both terminals where better low level
moisture should linger.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...99
LONG TERM...JBH
AVIATION...DR
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1043 PM EDT Mon Jul 3 2017
.SYNOPSIS...
High pressure will remain centered over the western Atlantic
while a broad upper level trough persists over the eastern part
of the nation for the better part of this week. A weak cold front
will linger over the region through midweek, helping to focus the
development of showers and thunderstorms. An upper level disturbance
later in the week will initiate pattern change, leading to drier
and somewhat cooler conditions late in the weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 1035 PM EDT: The late evening LAPS analysis has the only
residual instability to note across the western Upstate and upper
Savannah river region, but even there profiles are starting to
stabilize quickly. Will thus ramp down thunder chances to just the
lower piedmont through about 06Z, where an isolated heavy rain
threat will also persist. Regional radar loops have better coverage
across central and western TN late this evening ahead of the
approaching upper wave, but the HRRR suggest that this will diminish
as it moves east toward the southern Appalachians overnight. Will
still keep chance PoPs in the far western mountains for a possible
pre-daybreak arrival.
Otherwise, the general pattern does not change much over the next 24
hours. The main feature of interest is the aforementioned,
better-defined shortwave currently over west-central TN that will
approach the area overnight, but with most of the energy passing by
the GSP CWA to the north late tonight through Tuesday. This feature
should still combine with moist profiles and improving diurnal
instability Tuesday afternoon to yield a good chance of
thunderstorms again for Tuesday. Storms may be a bit stronger than
today, and the hydro threat will remain for localized excessive
rainfall. Temperatures will remain warm and humid with lows a little
above normal and highs near normal.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 200 PM Monday: Short wave ridging aloft will gradually develop
over the region during the short term, while weak E/W-oriented
surface boundary and lee side/thermal troughs will linger through at
least Wed. These features will provide additional focus for
development of scattered afternoon/evening showers and storms (in
addition to the usual ridge top convergence/differential heating
effects) on Wed and Thu.
By the end of Thursday, an anomalously strong short wave trough is
forecast to be moving across the TN and Ohio Valleys. Although model
solutions offer slight variations in location/timing, it would
appear that any forcing associated with this feature would most
likely impact the forecast area well after peak heating Thu night.
However, strengthening wind fields aloft will result in improving
shear profiles, which could support some low-end organization of
convective clusters, and severe weather potential slightly higher
than the run-of-the-mill early summer pulse activity. Temps are
expected to remain near to slightly above climo through the period.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 210 PM Monday: Low-amplitude long wave troughing will become
established across the East early in the medium range, and persist
through the period. Transitory short wave troughs passing near the
forecast area and attendant weak frontal passages are anticipated
Friday, and again in the Sunday/Monday time frame. These days are
therefore expected to see some degree of enhancement of diurnal
convective chances. In fact, timing of the initial short wave (Thu
night/early Friday) and attendant establishment of a LLJ Thu night
may allow convection to linger well beyond the typical diurnal
cycle. Otherwise, wind profiles should remain a bit stronger than
typical for the time of year, so the potential for low-end
organization of convection will persist each afternoon. Temps will
generally remain around normal through the period.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
At KCLT: Convection has greatly diminished late this evening and
expect little more than light showers through 04Z before the
coverage dissipates for the overnight hours. The moist ground could
yield some low clouds and fog overnight, but profiles and MOS do not
feature this. Will hint that way with FEW010 for now. Otherwise,
anticipate a repeat on Tuesday afternoon, with building daytime
instability followed by outflow and shortwave driven convection
leading to scattered thunderstorm coverage, or better, once again.
Winds will be gusty near thunderstorms and restrictions will likely
be IFR to MVFR in storms.
Elsewhere: Residual evening convection continues to wind down, with
the lingering threat mainly in the vicinity of KAND through 04Z. Any
lingering light rain should further diminish overnight. There is
some potential for overnight convection to return from the west with
the deamplifying wave moving east over TN, but confidence in any
precip at the mountain and foothills airports is too low to mention
overnight. Anticipate mountain valley fog and low cloud development
once again, and restrictions are quite possible at the foothills
sites given all the heavy rainfall. Will limit overnight foothills
IFR fog and MVFR cigs to KHKY, while KAVL should be solidly IFR (or
worse.) Anticipate light, generally south to southwest winds
returning Tuesday, with gusts possible near thunderstorms as
coverage builds once again through the afternoon hours.
Outlook: Moist and unsettled weather will continue through the week.
Nocturnal restrictions can be expected in locations receiving heavy
rainfall.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 94% Med 61% High 100% High 100%
KGSP High 100% High 81% High 100% High 100%
KAVL High 95% Low 46% Med 71% High 100%
KHKY High 88% High 91% High 95% High 100%
KGMU High 100% High 95% High 100% High 100%
KAND High 100% High 98% High 97% 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 and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...CSH
NEAR TERM...HG
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...HG
Area Forecast Discussion
National Weather Service Wilmington NC
730 PM EDT Mon Jul 3 2017
.SYNOPSIS...
Bermuda High pressure combined with tropical moisture will
bring heat and high humidity this week, with occasional
torrential rainfall associated with daily thunderstorms.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 730 PM Monday...Convection has made inroads to the areas
in the western CWA but little else. With the slow almost aimless
movement of the storms the coverage shouldn`t increase over the
next couple of hours as the loss of daytime heating plays a role
as well. I did decrease pops more dramatically for the next
couple of hours along the coast then more gradually through the
overnight hours while at least keeping a slight chance in all
areas. No other changes. Previous discussion follows:
Mid-level impulse will continue to help fire
scattered to numerous areas of convection through the remainder
of the afternoon and evening. Storms could back-build in an E-W
fashion leading to a few areas with substantial localized
rainfall. DCAPE has increased per SPC meso-analysis page which
could support a few strong storms, especially across the Pee Dee
and Lumberton areas. Otherwise the bulk of the storms are
expected to remain below severe limits. HRRR shows coverage of
storms becoming limited overnight. However, weak mid-level
troughing will persist into Tuesday, thus scattered showers and
thunderstorms are possible again during the day. Some of these
storm, particularly farther inland, may become strong once
again. Morning convection has played havoc with the temperature
fields at the onset, and subsequent max temperatures this
afternoon will vary since some areas were cloudy and others
received excellent insolation. Lows tonight will be above normal
given weak southwesterly flow. Highs during Tuesday will likely
range from around 90 in the ILM and LBT areas to the lower 90s
across the Pee Dee (upper 80s Grand Strand) but these numbers
will be highly dependent the convective coverage.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 3 PM Monday...After a few mid level disturbance interact
with surface low and boundary for at least scattered storms Tuesday
night Wednesday may feature a downward trend in convective coverage.
Mid level height rises poke up from the main ridge over Bermuda and
the main favored thunderstorm area will shift north of the area. The
WRF may beg to differ in showing the shortwave energy a bit further
south but its track record has been sketchy as of late. The EC
favors storms shifting north but not to the degree of the GFS as it
has a healthy shortwave passing by to our north. Will continue to
carry chance POPS area-wide but show a north-south gradient in rain
chances and amounts. Wednesday afternoon should warm up into the low
to mid 90s due to the decrease in convection/cloud cover.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 3 PM Monday...The extended period features a continuation
of unsettled weather as low-level convergence, relatively high
precipitable water values, and surface boundaries remain in good
supply. The elevated moisture will result in above normal min
temperatures, while daytime highs run near normal for early
July. Friday and Saturday look particularly wet, as a upper
trough slowly deamplifies along the Appalachians, and allows a
frontal boundary to stall along or near the coast late week into
next weekend. It appears aside from cloud to ground lightning
strikes, localized flooding will be the primary threat. Given
upper wind shear expected ahead of the upper trough, a few
storms could become strong to severe late Friday.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
As of 00Z...Expect mostly VFR to MVFR conditions through the
forecast period. However with showers and thunderstorms
currentli in close proximity to Lumberton and Florence, I did
add a tempo group for two hours for gusty winds and TSRA. Once
again the MET guidance is more agressive with IFR stratus in the
early morning hours especially inland but it has been way too
agressive the past few cycles. There may be an observation or
two with IFR stratus but feel it will be fleeting. Otherwise
similar conditions for Tuesday during the day with PROB 30
groups used to address scattered convection.
Extended Outlook...MVFR/IFR conditions are possible from early
morning stratus Wed. There is also a likelihood for daily flight
restrictions due to mainly afternoon and evening thunderstorms.
The risk for flight restrictions due to showers and
thunderstorms may begin to diminish later in the week.
&&
.MARINE...
NEAR TERM /THROUGH TUESDAY/...
As of 730 PM Monday...Minimal changes to the coastal waters
forecast this evening. I did decrease pops for the next couple
of hours but no changes to the winds or seas. Previous
discussion follows:
Southwest flow 10-15 knots will be the rule
outside of any convection this afternoon through Tuesday. Some
higher gusts are likely during the remainder of the afternoon
and evening, then again Tuesday afternoon thanks to the sea
breeze circulation. Seas will be 3-4 ft or less through the
period outside of any convection.
SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 3 PM Monday...Winds and seas just slightly higher than one
would expect for July. Whereas normally the wind and wave makers are
the Bermuda high and piedmont trough the latter will host a weak
area of lowered pressure for most of the period. This will add a few
knots of winds to the southwesterly flow and could lead to a few 4
ft waves along the outer portions of the area.
LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 3 PM Monday...Near typical marine weather conditions for
the extended period as Bermuda High pressure maintains SW winds
across the waters. A stalled front inland however, may increase
winds to the 15-20 KT range on Friday with seas possibly
building to 3-5 feet. As a result an `exercise caution`
headline may be needed for late in the week. Showers and TSTMS
will be active this period, and radar updates will be beneficial
late week.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...MJC
NEAR TERM...SHK/SRP
SHORT TERM...MBB
LONG TERM...MJC
AVIATION...SHK
MARINE...
Area Forecast Discussion
National Weather Service Lincoln IL
900 PM CDT Mon Jul 3 2017
.UPDATE...
Issued at 900 PM CDT Mon Jul 3 2017
Forecast generally on track tonight with mostly clear to partly
cloudy skies and isolated shower or thunderstorm this evening
along and north of I-74. Lows in the mid to upper 60s, coolest
north of I-74. Added patchy fog later tonight to sw 1/4 of CWA
where HRRR shows a few patches of fog appearing in moist airmass
and light wind regime especially near Lake Shelbville and lower IL
river valley.
Isolated thunderstorm dissipated south of Bloomington and east of
Heyworth before it reached into DeWitt county. Another
thunderstorms diminished too as it tracked se into far nw Knox
county. Mainly outflow boundary/cold front was pushing slowly ssw
toward I-74 at dusk and may still have isolated convection this
evening but most areas will stay dry tonight with mostly clear to
partly cloudy skies. Weak surface low pressure of 1014 mb in nw TN
had scattered convection in southeast IL south of I-64 and this to
stay south of CWA rest of tonight. Lows tonight in the mid to
upper 60s with coolest readings north of I-74 where outflow
boundary has passed. Muggy dewpoints in the mid 60s to lower 70s
to support patchy fog formation later tonight in sw 1/4 of CWA
especially near waterways and should dissipate by 8 am.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 300 PM CDT Mon Jul 3 2017
The cold front across northern Illinois has activated with a
broken line of storms, and very slow southward drift is noted in
the radar and satellite loops. The general consensus of the high
resolution models is for the front to eventually reach to our
northern counties this evening, with spotty showers and storms
developing, mainly for areas along and north of I-74. A few spotty
showers may develop as far south as Lincoln and Decatur, but areas
south of I-74 should remain primarily dry the rest of this
afternoon and tonight. While the front drops south into the area,
a low pressure center is projected to pass across far southern
Illinois tonight, with showers remaining just south of our
southeast counties /Hwy 50/. Will continue a dry forecast for our
central and southeast counties, and also continue slight chance
PoPs for our northern counties for this eve. Steering winds are
weak at best, so any storms will be slow moving, with the
potential to drop heavy rainfall over a short period of time. Some
ponding could develop on roads in poor drainage and/or lower
areas.
Dry conditions should develop by midnight, with a break in the
rain chances through the morning of July 4th. However, the
location of the stalled frontal boundary will likely be the focus
for scattered showers/storms during the afternoon on July 4. At
this point, that looks to be mainly north of a line from Canton to
Bloomington, where we have 30% PoPs. Slight chance PoPs /20%/
were included in the remainder of our forecast area for late
afternoon, due to uncertainty in the location of the front and any
storm triggers.
Temps tonight look to be held up by mild dewpoints in the mid 60s
to low 70s. Muggy conditions are expected overnight as lows bottom
out between 65 and 69 deg. Humid conditions will continue on July
4 as highs reach the upper 80s, with heat index readings in the
low to mid 90s in the shade.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 300 PM CDT Mon Jul 3 2017
The extended forecast starts out with the evening of July 4, when
most guidance is showing a marked decrease in precipitation
chances for most of central and southeast Illinois. Due to an
approaching low pressure system from the west, we kept a narrow
ribbon on slight chance PoPs in our far western counties Tues
night, from Galesburg to Jacksonville. Otherwise, the remainder
of the area should remain dry for any mid to late evening
activities/events on July 4.
The low pressure center will make steady progress toward Illinois
on Wednesday, with rain/storm chances increasing through the day.
The 12z guidance has shown a small decreasing trend in precip
chances from Wed to Thursday, as low pressure passes across
Illinois, roughly along I-70. We have reduced the coverage of
Likely PoPs /60-70%/ to areas along and south of I-72/74 to
Danville, starting in our SW counties Wed afternoon and expanding
eastward through Thursday morning. There will be plentiful
moisture available for any storms that develop, with locally heavy
rainfall and flooding possible. Precip water values look to climb
into the 1.75" to 1.9" range during that time. The WPC day 3
excessive rainfall outlook does contain a Marginal Risk /2-5%/
for potential to exceed Flash Flood Guidance Wed afternoon-Wed
night all across our forecast area. The latest QPF output is now
generally focusing the better potential for heavy rain south of
I-72/74 to Danville.
After that system departs Thurs afternoon, a long wave trough
will become established into the Great Lakes and the eastern half
of the lower 48 for the last part of the week and weekend, while a
prominent warm ridge builds in the western CONUS. That will set
the stage for NW flow into Illinois for an extended period, which
usually means more frequent chances for rain/storms. However, the
next cold front slated to arrive on Friday afternoon looks to only
produce spotty showers/storms for our far northeast counties, N
of Bloomington to Champaign. Dry conditions look to return Friday
night and continue through Monday. The models typically have
trouble resolving individual shortwaves in the later extended
forecast, but for now, we will go with the dry and slightly cooler
extended forecast. Highs should remain mainly in the lower 80s
from Saturday to Monday, with relatively comfortable dewpoints in
the mid to upper 50s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 655 PM CDT Mon Jul 3 2017
One very isolated thundershower suddenly appeared over the BMI
airport during past hour with vsby briefly down to 1.75 miles with
heavy rain (0.55 inches in about a half hour) and broken ceiling
to 4k ft. This thundershower has drifted slowly south of BMI
airport and near Downs IL, but continued VCTS at BMI until 01Z.
An outflow boundary/cold front was pushing southward toward I-74
early this evening and currently extended from just north of Knox
county, through central Woodford county to just north of McLean
county. Isolated convection possible along this boundary this
evening as it drops just south of i-74 after dusk this evening.
Carried vcsh at PIA, BMI and CMI this evening which will be
closest to this boundary. Diurnally driven isolated convection to
dissipate overnight and then reappear during mid/late Tue
afternoon along I-74 where boundary will linger. Winds to stay
light next 24 hours 3-7 kts, starting out southeast early this
evening and veering ENE by overnight and continue Tue.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...07
SHORT TERM...Shimon
LONG TERM...Shimon
AVIATION...07
Area Forecast Discussion
National Weather Service Northern Indiana
943 PM EDT Mon Jul 3 2017
.SYNOPSIS...
Issued at 236 PM EDT Mon Jul 3 2017
A cold front will drift south through the forecast area this
evening. This will lead to scattered showers and thunderstorms,
especially along and south of highway 30. Though we could see a
few stronger storms, severe weather is not expected. Precipitation
activity should die out after sunset. Lows will be in the 60s.
Independence day looks to be partly cloudy with highs ranging from
80 to 85 degrees. There is a slight chance for showers and
thunderstorms along and south of highway 24...west of interstate
69. Severe weather is not expected.
&&
.UPDATE...
Issued at 937 PM EDT Mon Jul 3 2017
Coverage and intensity of convection has diminished greatly over
the past hour or so. A few showers/isol thunder were persisting
from southeastern Kosciusko county to Fort Wayne. Other activity
also noted moving into far NW Indiana (Lake/Newton counties). HRRR
has once again done a great job with convection this period, even
showing the positioning and somewhat the strength of the severe
cells from earlier. As such while gut is to lower pops over the
next hour or 2, will keep a high slight chc with the NW Indiana
convection that the HRRR and even 18Z NAM showing continued or
slightly renewed convection moving across the area, mainly along
and south of route 30. Will monitor trends into the overnight
hours. Should not be anything severe, but at least 500 j/kg MLCAPE
noted to at least help maintain them.
&&
.SHORT TERM...(This Evening through Tuesday)
Issued at 236 PM EDT Mon Jul 3 2017
Isolated showers percolating across MI have largely dissipated with
orphaned frontal boundary slowly sagging south across our CWA. Still
some capping noted on hourly forecast soundings and mesoanalysis but
continual diabatic heating and sufficient low level moisture still
expected to generate 1000-1500 J/kg of uncapped MLCAPE this
afternoon, mainly along and south of US-30. With modest low level
convergence in place, expect ISO/SCT showers and storms in our south
through the evening. Deep-layer shear values are marginal south of
the front (generally less than 25 kts) but suppose its not
impossible to see an isolated damaging wind gust given moderate
instability. Convection will likely remain pulsey with little/no
organization. Isolated showers could continue through much of the
night but expect bulk of the activity will simmer down after 01-02Z
and kept the post-06Z period dry. Overnight lows will be similar to
last night...mid 60s in south and around 60F to the north given
cooler/drier postfrontal air and less cloud cover.
Left Tue primarily dry with most 12Z guidance continuing trend of
stronger AVA/subsidence and surface high pressure over the Great
Lakes, forcing surface boundary just S/SW of our CWA. A stray shower
may clip our far southern zones but expect primarily dry conditions.
Temps and dewpoints may be a degree or two cooler but temp/moisture
advections not particularly strong and will be similar to today.
&&
.LONG TERM...(Tuesday Night through Monday)
Issued at 236 PM EDT Mon Jul 3 2017
12Z guidance also continued earlier noted trend of later and more
southern track to Wednesday night`s wave. 12Z deterministic GFS even
suggests most of the CWA will remain dry. Confidence in any one
scenario remains low with high degree of spread in ensemble guidance
and uncertainties with regard to convective modulation upstream.
Tried not to make drastic changes to PoP forecast but did lower them
a bit (and push them more into Thu) based on latest consensus. Heavy
rain still possible given seasonably strong CVA forcing, and ample
moisture but obviously will depend on track as to whether our
counties are impacted. Better chances look to be south of US-30 at
this point. Cold front still set to pass through on Friday but sharp
difference in GFS and 03.00Z ECMWF handling of next longwave
trough/closed low leading to high uncertainty with regard to weekend
forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 730 PM EDT Mon Jul 3 2017
A front continues to reside near the MI/IN border and may slide
ever so slowly south into later Tuesday. This will help to provide
mainly FWA with shower and thunder chances before sunset with
ample CAPE and minimal shear/helicity around the region tonight.
Expecting these to dissipate towards sunset along with the
instability. Despite the rain from today`s storms, still see
conditions remaining in VFR overnight. Some showers and maybe a
storm is possible once again on Tuesday. Expect those to remain
south of SBN, but can`t rule a storm out at FWA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...Fisher
SYNOPSIS...MCD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Roller
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Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
630 PM CDT Mon Jul 3 2017
.SHORT TERM...
156 PM CDT
Through Tuesday...
Thunderstorms coverage and timing comprise the main forecast
concerns for the remainder of this afternoon as a weak stationary
frontal boundary is draped across the area. The boundary is a bit
diffuse early this afternoon but stretches from roughly SQI
(Sterling, IL) ese through JOT (Joliet, IL) and to just north of
RZL (Rensselaer, IN). A modest Cu field has blossomed roughly
20-30 miles on either side of the aforementioned line and appears
will be the main area of concern for thunderstorms initiating by
around mid afternoon. Latest SPC mesoanalysis indicates a corridor
of 1000 J/kg MLCAPE aligned with the aforementioned front with
little or no CIN in place. Latest several runs of the HRRR and
ESRL HRRR along with the NAMNest have been in decent agreement on
convective initiation occurring by around 19/20Z with coverage
increasing to widely scattered to scattered. Deep layer shear in
the region remains weak thus think the primary concern will be
with up-and- down pulse storms with an low end localized wind
threat owing to steep low level lapse rates and dry mid level air.
As coverage increases, outflow spreading south should push the
best precip chances farther south across the CWA with activity
waning mid through late evening as we begin to lose daytime
heating. Overall synoptic setup doesn`t change too terribly much
over the next 24 hours. Guidance indicates the high centered over
the central Great Lakes region will sink a little farther south
which should result in the best precip chances also setting up a
little farther south tomorrow as compared to today. That said,
much of the area looks to become unstable again, except for areas
near the lake front impacted with onshore flow, which means cannot
rule out at least an isolated storm over much of the CWA.
Deubelbeiss
&&
.LONG TERM...
231 PM CDT
Tuesday night through Monday...
The primary forecast concerns/challenges will be the potential
for rain and thunderstorms along with temperatures mid to late
week.
A mid/upper-level ridge will continue to build over the western
CONUS on Wednesday as a compact convectively enhanced shortwave
trough shifts eastward over the lower Missouri Valley. This
convectively enhance shortwave trough has, and continues to be
the main feature of interest that could impact the sensible
weather across portions of the area late Wednesday into early
Thursday. Confidence in the actual evolution of this feature
through midweek does remain a bit on the lower side. This is
mainly due to the fact that much of the convection expected to
enhance this disturbance is not set to develop until later today
and tonight over the Plains. However, recent forecast guidance has
began to shift the main eastward track of this disturbance
farther south over southern IL and into the Ohio Valley late
Wednesday into Thursday. As a result this would support the
heavier rain and thunderstorm potential into late Wednesday into
Thursday morning mainly over southern portions of IL and IN.
Temperatures with less precipitation on Wednesday will again be
able to top out in the mid 80s, though onshore flow is likely to
again result in cooler conditions near Lake Michigan. On Thursday
it appears that more muggy conditions will set up over the area as
the low-level flow turns west-southwest out ahead of a southward
moving cold frontal trough over the Upper Midwest. Temperatures
again are likely to top out in the mid to upper 80s, with some
areas possibly near 90. This could push heat indices into the low
to mid 90s with surface dew points expected to be near 70. There
is the potential for a lake breeze to turn the winds onshore
Thursday afternoon, but it appears unlikely at this time that this
lake breeze would move very far inland over northeastern IL, so
any lake cooling appears minimal at this time.
Thunderstorm chances will remain in the forecast, especially
Thursday afternoon and night as the aforementioned cold front
shifts towards the area. Many areas could remain dry for much of
the day on Thursday, but with the approach of the cold front,
thunderstorms do look possible over portions of the area Thursday
night. With these storms, we cant rule out the possibility for
some strong to severe threat. However, at this time it appear the
poor diurnal time of day (Thursday night) of the frontal passage,
this threat could end up limited.
Following Thursday nights cold frontal passage it appears that a
much cooler airmass will shift over the area for the weekend as
surface high pressure builds over the area. This should set up a
quiet and dry...but cool...weather pattern over the area for a few
days. Temperatures may only top out near 80 inland and in the 70s
near the lake next weekend. There are questions about the
prospects of another cold frontal passage later this weekend. If
this were to materialize, this could result in another chance for
thunderstorms on Sunday. However, confidence on this is low at
this time.
KJB
&&
.AVIATION...
For the 00Z TAFs...
Forecast items of interest with the Chicago area TAFs heading
into Independence Day are:
- Vicinity showers early this evening
- Chance of MVFR ceilings overnight and early Tuesday morning
- Some chance of smoke/haze from nearby fireworks tonight and
again on Tuesday night
A weak frontal boundary draped from near the Quad Cities through
northern Indiana will move ever so slowly south into Tuesday. This
had triggered scattered thunderstorms earlier which aren`t much
more than isolated now and should continue a gradual fade through
mid-evening. Short-lived showers are nearby ORD and DPA as of
2315Z, but not expecting these to last TOO long and with only a
slow east movement. These could near MDW early this evening as
well.
Along and north of the boundary, there is some pooling of moisture
for broken 2000-4000 ft ceilings. There had been some of this
during the day and could see redevelopment tonight into early
Tuesday morning. Confidence on this is low. As for the IFR that
formed today near the lakeshore, there has been some drier push to
lakeside areas in the past 24 hours, so thinking that is not as
likely.
The wind pattern will continue with a generally northeast wind. A
re-increase to around 10 kt is expected mid-morning on Tuesday.
Some fluctuation between 020 and 100 degrees is possible tonight
and early Tuesday morning.
Looking back at the past four years of Independence Day night
observations, the MDW observed has reported 7SM or less visibility
during the late evening in part or entirely due to smoke from
nearby fireworks. ORD has reported some haze at times as well. As
for the night of the 3rd there has not been any smoke reported in
these past few years, so have none in the TAF for this evening but
there are numerous community firework shows. Just something to
note these next two evenings.
MTF
&&
.MARINE...
241 PM CDT
A surface ridge of high pressure will gradually shift over the
northern portion of the lake tonight into Tuesday, and this will
continue to result in a period of light and variable winds over
the northern part of the lake. This surface high is forecast to
shift towards the eastern lakes by Wednesday and this should allow
the winds to turn back to a southerly direction. A cold front is
likely to shift over the lake Thursday night. A period of
thunderstorms will be possible with this frontal passage. However,
in its wake, expect a period of stronger northerly winds to set
up over the lake Friday. It appears surface high pressure will
then gradually build in over the lower lakes region over the
weekend.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Memphis TN
908 PM CDT Mon Jul 3 2017
.UPDATE...
Showers with a few embedded thunderstorms continue this evening
across portions of West Tennessee and Northeast Mississippi. Looks
like the convection may linger into the overnight hours
especially across areas of West Tennessee near the Tennessee River
according to the latest HRRR run. In addition, convection
occurring across Oklahoma may hold together and reach Eastern
Arkansas around 12Z. Updated earlier to adjust highest POPS near
the Tennessee River. Will do one more update to adjust POPS a
little higher across Northeast Arkansas to account for the
possible convection moving in around 12Z.
KRM
&&
.DISCUSSION... /issued 316 PM CDT Mon Jul 3 2017/
Beginning to see a fair amount of redevelopment on radar early
this afternoon across Northeast Arkansas and the Missouri
Bootheel. These showers will track to the East Northeast at around
30 mph. They will track across areas that received over four
inches of rain this morning. However, rain rates are not expected
to be as high as we saw this morning and flooded areas have had
ample time to drain. No lightning has been detected with the new
development so far and conditions are only modestly unstable. The
Storm Prediction Center has included most North Mississippi in a
Marginal risk for severe thunderstorms this afternoon. Will
advertise low confidence of Strong storms in the HWO.
Overnight...showers should taper off although short term guidance
does show some redevelopment before sunrise. Independence Day
looks a bit warmer and a little drier than we have seen recently
with highs in the middle to upper 80s. Heat indices will be in the
low to middle 90s.
Over the next several days a trough will deepen over the
Midsouth...oriented from Minnesota into East Oklahoma. As a
result...rain chances will remain enhanced across the region. The
trough axis should shift East of the Mississippi River Thursday
with higher rain chances over West Tennessee and North
Mississippi.
Friday and Saturday look warmer with highs in the upper 80s to
near 90. Showers and thunderstorms late in the work week into next
weekend look primarily diurnally driven in nature.
30
&&
.AVIATION...
MCV is exiting the area and the SHRA/TSRA chances will be
diminishing over the next couple of hours. Expect mainly VFR
conds this evening with IFR/MVFR cigs likely at KMKL/KTUP later
tonight and early Tuesday. Lower cigs also possible at KMEM though
not confident enough to go with a BKN ceiling yet. Tuesday`s
forecast is a work in progress. At this point it looks like
another upper level disturbance moving in Tuesday afternoon so
added VCSH/VCTS to account for this.
SJM
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
324 PM MDT Mon Jul 3 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 324 PM MDT Mon Jul 3 2017
A weather disturbance will continue affecting southeast Colorado
this evening, and will probably bring scattered showers/tstms to the
far southeast plains. The rest of the forecast area is expected to
continue seeing isolated showers/tstms thru the evening hours. With
drier lower levels from about the I-25 corridor and westward, the
main storm threats this evening are expected to be strong wind gusts
up to 55 mph, along with lightning. Acrs the far southeast plains,
where the lower levels are more moist, there could be a better
chance for one or two severe storms with hail an inch or larger in
diameter and wind gusts around 60 mph. The HRRR and NAM are showing
pcpn chances ending by about midnight.
On Tue the upper ridge will build back over the area. Moisture will
be somewhat limited over the area on Tue but there will still be
some isolated showers/tstms, mainly over and near the mtns. Temps
on Tue will reach highs that are a few degrees above average.
.LONG TERM...(Tuesday night through Monday)
Issued at 324 PM MDT Mon Jul 3 2017
From the Fourth of July Evening into Wednesday Evening, the
thunderstorms that develop off of the Rocky Mountains earlier in
the day will continue to affect southeastern Colorado, which
unfortunately means that cloud cover will exist during the
fireworks shows across most of the region.
During the overnight hours, an upper-level ridge will continue
to build over the region, clearing the skies and bringing in drier
air. Diurnal flow will produce isolated thunderstorms over the
mountains late in day. The thunderstorms that do develop will be
slow moving due to weak steering flow aloft, meaning that
thunderstorms that do develop over the mountains may produce
locally heavy rain.
Increasing pops in combination with near to above seasonal early
July temperatures are then anticipated from Thursday into early
next week as upper ridging becomes centered from the 4-Corners
region into northern Arizona during this time-frame. In addition,
adequate atmospheric moisture combined with the orographic
heating cycle, subtle upper disturbances and surface boundaries
will allow daily rounds of basically isolated to scattered showers
and thunderstorms from Thursday into next Monday(generally
favoring higher terrain locations).
Some of these storms will be capable of generating locally heavy
rainfall and also may become quite intense at times. At this time,
it appears that the highest potential for more widespread
precipitation during the longer should be experienced from later
Thursday into Thursday evening, Friday into Friday night and then
again during the weekend.
Finally, generally near to above seasonal early July temperatures
are anticipated during the longer term with warmest conditions
expected Wednesday and Thursday(with maximum temperatures nearing
the Century Mark at select eastern locations).
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 324 PM MDT Mon Jul 3 2017
VFR conditions are expected at KCOS, KPUB and KALS thru the next 24
hrs. There will be the possibility of showers/tstms at the terminal
forecast sites this evening and possibly Tue afternoon. The main
threat from the storms will be strong wind gusts, possibly between
35 and 45 kts.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Area Forecast Discussion
National Weather Service Blacksburg VA
934 PM EDT Mon Jul 3 2017
.SYNOPSIS...
Weak upper disturbances will continue to cross the region from
the west through late Tuesday resulting in periods of showers
and storms into Tuesday evening. A backdoor front shifts south
into our area Tuesday night and Wednesday before lifting back
north as a warm front Thursday. Waves of energy traveling along
this boundary will increase the chances for showers and storms
through late week.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 931 PM EDT Monday...A few widely scattered thunderstorms
have developed along the Floyd/Patrick/Carroll County line in
the past hour or so. These cells are very slow to move given
weak wind fields aloft, and while they are not producing any
hydro problems, their slow storm motions are contributing to
heavier rain/downpours. Meanwhile, we continue to monitor
ongoing showers and embedded thunderstorms in two additional
areas: one from residual outflow from the central Carolinas in
the NC Piedmont Triad area and what was earlier stronger storms
over the Tri- Cities TN area. Though finer- resolution CAM
output has struggled with the evolution this evening, recent
runs of the HRRR suggest weakening through midnight in each of
the three aforementioned areas given that the sun has set. That
still seems like a reasonable outlook, with a lowering trend to
PoPs shown.
Aside from essentially nowcasting current conditions, I did opt
to increase lows by a couple degrees with SCT to OVC mid-level
cloudiness having overspread areas mainly west of a line from
Lynchburg to Yanceyville. Kept idea of patchy fog going along
the NC foothills and into Surry and Stokes counties, as most of
these areas did get wet and T-TD spreads are narrowest. The
added cloudiness overnight does cast more question marks. Lows
should be rather uniform in the mid 60s to lower 70s.
Previous discussion issued at 651 PM Monday follows...
Break from earlier showers and thunderstorms which affected the
immediate foothills and High Country of North Carolina has
drifted further southeastward. However, on the sub- synoptic
scale, an expansive outflow boundary stemming from strong
convection over central and eastern NC/SC may trigger additional
pop-up showers and thunderstorms through sunset as it builds
northwestward into Stokes, Rockingham and Caswell Counties where
axis of greatest, albeit marginal, instability still resides.
Scattered showers and storms also exist across northeastern TN,
which should progress into Ashe and Watauga Counties. All that
said, I`ve maintained isolated/scattered showers and isolated
thunder until 02z/10 pm across much of our NC counties. A
general decrease in shower and storm coverage should take place
with sunset. Much of VA and WV should stay dry as the air mass
here is notably stable due to lower dewpoints.
Well to the west, a large canopy of mid to high-level clouds
from upstream convective debris and moisture associated with
mid-level shortwave over western TN will continue to spill
eastward through the overnight. I`ve made no changes to low
temperatures for now, but upward adjustments may be needed later
if cloud shield is thick enough.
Previous near-term discussion issued at 205 PM EDT follows...
A theta-E boundary sits along the VA/NC border this afternoon. North
of this boundary is dry with dew points in the mid 50s to lower 60s.
South of the boundary is humid with dew points in the mid to upper
60s. Showers and thunderstorms developed this afternoon over the
North Carolina High Country will track east over the NW NC foothills
into early this evening. These showers may not last past sunset and
will continue to track east into drier stable air. This boundary
will slowly lift north overnight as a short wave trough moves east
of the mid Mississippi Valley. Temperatures this evening should drop
sharply for areas north of the theta-E boundary, but level off after
midnight as boundary lifts north. Overnight lows will range from the
low 60s across the mountains to low 70s across Southside.
A short wave trough will slowly track east across TN/KY tonight.
Thanks to a stubborn upper level ridge in the western Atlantic, this
wave may not make it into the area until late tomorrow afternoon.
Even though this wave is weakening, it will bring showers and
thunderstorms into the region during peak heating tomorrow. Strong
to severe storms are possible with a few producing wet microburst
and hail. Slow moving storms and high rainfall rates could also lead
to flash flooding.
Tomorrow`s temperatures may be a little cooler than previous
forecast thanks to the short wave trough. Guidance has backed-off on
highs tomorrow by 5F or so. Since showers are not expected until
late in the afternoon, this may be in response to debris clouds over
taking the region as the wave approaches. High temperatures likely
to range from the upper 70s to lower 80s in the west to mid to upper
80s east.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 230 PM EDT Monday...
Rather wet period in store with rounds of showers and storms
possible as impulses kick east around a residual upper trough and
along a stalled boundary that will drop south into the area by
Wednesday. Once such shortwave looks to arrive on Wednesday, perhaps
preceded by organized convection espcly over the south and east
where higher PWATS will have returned. Best convergence looks to
develop Wednesday with heating as the weak front slides south aided
by weak low pressure over the Carolinas. This may bring heavy
rainfall given moisture and low level southeast flow into a
developing wedge. Think potential enough for more widespread showers
and storms so running with period of likely pops most spots during
the afternoon.
Wave exits Wednesday night ahead of a more potent impulse that will
lift northeast from the central Plains toward the Ohio Valley by
late Thursday. Models continue to have differences in the expanse of
the warm advection convection south of this feature along with just
how far east better upward motion will get into Thursday night.
However latest trends off the 12Z ECMWF a little more in line with
the GFS in suggesting a band of deeper convection may occur over the
northwest counties, with at least scattering of shra/tsra elsewhere
as a warm front lifts back north ahead of the wave. Appears late
arrival into points east of the mountains may limit better coverage
there so ranged pops from likelys northwest to lower chance
southeast for now into Thursday evening.
High temps mostly in the 80s although could be cooler Wednesday if
clouds/showers develop sooner and the weak wedge spills in by
afternoon across central/eastern sections. Should see a quick
rebound to 80s/around 90 east Thursday as return flow develops ahead
of the stronger wave/front approaching from the west.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 200 PM EDT Monday...
Upper trough will again become better established across the region
through much of the period as a series of shortwaves rotate through
bringing subsequent cold frontal passages through early next week.
However timing and spatial distribution of convection remains
uncertain toward the end of the week given slower trends of guidance
of late. Otherwise appears one such impulse should cross the region
Friday with a trailing cold front working through behind associated
surface low pressure passing across the Mid-Atlantic Friday morning.
This along with heating likely to bring another round of
showers/storms into Friday afternoon before seeing some slight
drying within northwest flow Friday.
Secondary more potent upper feature then looks to arrive Saturday
with a stronger surface cold punching through from the northwest
during the day. Appears moisture may be lacking behind the initial
boundary Friday, but enough to support some chance pops again into
Saturday afternoon. Somewhat drier air will arrive under high
pressure from the north Sunday into Monday but lots of questions in
whether or not deeper moisture gets pushed entirely out of the area
as the upper trough lifts out by early next week. Thus will leave in
some isolated/diurnal pops for Sunday/Monday but expecting more
sunshine by then. Temps likely to remain a bit above normal levels
early on ahead of the fronts before cooling to near seasonal values
by Monday.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
As of 651 PM EDT Monday...
Generally VFR at the terminals for the overnight hours. A pop-up
shower or thunderstorm still is possible through 02z at
Danville, but confidence is too low on timing and occurrence to
place in the TAF. There will continue to be showers and
thunderstorms dotting the southern Blue Ridge/NC mountains as
well for aviation interests with flight routes through the
mountains. May also see development of patchy fog in these same
areas in the overnight but away from the TAF sites. Winds light
to calm.
For Tuesday, expect continued FEW to BKN mid-level clouds with
VFR conditions through the morning. Potential then exists
for showers and thunderstorms in the afternoon, forced by
daytime heating and a mid-level disturbance over western
Tennessee. Difficult to pinpoint impact to any specific
terminal, so I`ve indicated VCSH for now over a broad time
range in the early afternoon; this will need to be better
refined in later TAF issuances. Potential for localized
turbulence, lightning and sub-VFR conditions in thunderstorms.
Winds should remain on the light and variable side, though may
trend east to southeast during the afternoon.
Extended Aviation Discussion...
The residual boundary will remain just south of the region on
Tuesday as another front dips south toward the area by midweek.
Upstream disturbances will likely impinge upon the moisture and
this next frontal boundary to result in added
afternoon/diurnally driven convection. Periods of MVFR cigs will
be possible in this activity, most numerous initially closer to
the NC/VA border, but likely impacting all areas as the week
progresses.
Late night and early morning fog can also be expected with
increasing probability through the week, especially given the
increasing potential for late day/evening rain at many TAF
sites. Convection may become more numerous toward the end of the
week as a stronger upper-level system approaches from the west.
All- in-all, likely to be an unsettled week, but periods of VFR
can certainly be expected.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...AL/RCS
SHORT TERM...JH
LONG TERM...JH
AVIATION...AL/RCS
Area Forecast Discussion...UPDATED
National Weather Service San Angelo TX
641 PM CDT Mon Jul 3 2017
.AVIATION...
/00Z TAFS/
VFR conditions are expected through the next 24 hours at all
TAF sites except KJCT, and showers and thunderstorms are
expected to stay north of KABI and west of our other TAF
sites this evening into tonight. Showers and thunderstorms
over parts of West Texas are expected to stay west of our
TAF sites before dissipating early tonight. Other thunderstorms
developing northwest of Lubbock and into the eastern Texas
Panhandle will move southeast through this evening and tonight,
but these should stay north of KABI. By early Tuesday morning,
patchy low cloud development is expected over the Northwest Hill
Country, affecting KJCT with MVFR ceilings. With patchy and
limited coverage of low clouds anticipated, only carrying a
scattered layer at KSOA and KBBD. Low clouds should break up
around mid-morning at KJCT. Southeast winds this evening will
veer to the south overnight. On Tuesday, south winds will increase
to 10-15 knots at all of our TAF sites by mid-to-late morning,
with gusts to around 20 knots.
19
&&
.PREV DISCUSSION... /issued 339 PM CDT Mon Jul 3 2017/
SHORT TERM...
(Tonight and Tuesday)
Light showers in the Big Country at 330 PM are forecast to dissipate
in the next hour or two as they move southeast. Scattered
thunderstorms, however, developing near Alpine, will move east
toward West Central Texas tonight. Most of the showers are expected
to dissipate as they move into the Concho Valley toward sunset,
though HRRR does keep a few storms going overnight across the Big
Country. Additionally, late tonight into Tuesday, an upper shortwave
moving across Oklahoma in northwest flow aloft may produce a few
storms in the Big Country. Main hazard from showers or thunderstorms
will be strong gusty winds.
Continued warm otherwise with highs of 95 to 100 Tuesday. Lows
tonight will be in the mid 70s.
04
LONG TERM...
(Tuesday Night through Monday)
Middle and upper troposphere flow from the northwest will
continue to bring the potential for weak disturbances moving
southeast across northern counties of west central Texas and with
them a few enhance chances for showers and thunderstorms. The
next upper level disturbance will arrive on Wednesday resulting in
a 20 to 30 percent chance of showers over northern and eastern
counties. A second weaker pulse is expected on Thursday with a 15
to 20 percent chance for showers across most of west central
Texas. Between pulses and after Thursday rain potential drops
away to 5 to 15 percent chances of isolated showers or
thunderstorms. Any rain chances will be highest during late
afternoon and early evening hours at or a few hours after times of
greatest surface air temperatures. Rain chances will remain very
low during cool morning hours.
Surface winds will continue to be mostly from the south or
southeast through Monday with wind speeds mostly in the 10 to 15
mph range during daytime hours dropping to 5 to 10 mph overnight
into early morning hours.
This weather pattern will produce high temperatures mostly in the
mid to upper 90s with low temperatures in the low to mid 70s. A
slight warming trend is expected by next Sunday and Monday when
daytime temperatures may reach or exceed 100 degrees.
22
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 75 98 74 94 / 20 20 10 20
San Angelo 75 101 74 97 / 20 10 10 20
Junction 74 96 74 95 / 5 5 5 10
Brownwood 74 96 73 94 / 5 10 10 20
Sweetwater 74 97 74 94 / 30 20 10 20
Ozona 73 96 73 95 / 20 5 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Tucson AZ
250 PM MST Mon Jul 3 2017
.SYNOPSIS...Expect isolated to scattered mainly afternoon and
evening thunderstorms into this weekend. The bulk of these
thunderstorms will be east to south of Tucson. High temperatures
will remain a few degrees above normal into this weekend.
&&
.DISCUSSION...Isolated showers and thunderstorms were occurring
mainly near some of the mountain ranges of southern Graham/Cochise
Counties at this time. Otherwise, visible satellite imagery and
surface observations depicted mostly clear skies from Tucson
westward into western Pima/southern Pinal Counties, and partly
cloudy skies east to south of Tucson.
Although MLCAPE as per SPC Mesoscale Analysis ranged from 250 J/kg
across eastern sections to 1000 J/kg west of Tucson, MLCIN values
apparently are sufficient to have limited shower/tstm development to
just isolated coverage so far this afternoon. Have noted that
successive HRRR solutions after 16Z have consistently trended precip
potential downward for this evening with each newer HRRR solution
received.
Expect isolated to scattered showers/tstms mainly east to south of
Tucson this evening. Have maintained a slight chance of showers/
tstms for the Tucson metro area this evening, but this notion is
probably exaggerated. Have also maintained a slight chance of
showers/tstms late tonight from the Tohono O`odham Nation
southeastward into Santa Cruz/southwest Cochise Counties. However,
this scenario may also be overdone, but will defer to the evening
shift to remove this mention/depiction as necessary.
The global-scale models remained quite similar versus their
respective solutions regarding the evolution of an expansive area of
high pressure to be established over the western/central CONUS
Tuesday and continuing into the upcoming weekend. The GFS/ECMWF/CMC
and their respective ensembles are suggesting that Tuesday and
Wednesday will be relatively "down days" regarding precip potential.
Thus, expect only isolated coverage of afternoon/evening showers/
tstms Tuesday and Wednesday mainly east-to-south of Tucson.
Thereafter, a very gradual daily coverage of showers/tstms should
occur Thursday into early next week. However, have noted that the
03/12Z GFS/ECMWF were not quite as robust with liquid accumulated
rainfall amounts, particularly for this weekend, versus their
respective solutions from 24-48 hours ago. Still, the official
forecast continues with scattered afternoon/evening showers/tstms
east of Tucson next Monday, and isolated showers/tstms from Tucson
westward into western Pima County.
High temperatures Tuesday will be nearly identical to temps achieved
this afternoon. Expect about a degree-or-two of daily warning
Wednesday into Friday, then high temperatures will lower closer to
seasonal normals by early next week.
&&
.AVIATION...Valid thru 05/00Z.
Isolated to scattered -TSRA/-SHRA east to south of KTUS ending
around midnight tonight. Isolated -TSRA/-SHRA Tuesday afternoon
south to southeast of KTUS and northeast of KSAD. Otherwise, VFR
conditions with surface wind this evening and Tuesday afternoon
wly/nwly 8-18 kts with gusts to 25 kts. Surface wind variable in
direction less than 12 kts at other times. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Isolated to scattered mainly afternoon and evening
thunderstorms will occur into next weekend, with the bulk of
thunderstorms occurring east to south of Tucson. Expect brief
strong, gusty and erratic winds near thunderstorms. Otherwise,
west to northwest afternoon 20-foot winds at 5-15 mph will occur
through Wednesday, then east to southeast winds will prevail
Thursday into the upcoming weekend.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Francis
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