Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/01/19
Area Forecast Discussion...Updated
National Weather Service Billings MT
848 PM MDT Sat Aug 31 2019
.UPDATE...
Upper ridge over the southern Rockies was keeping southern
Montana and northern Wyoming dry. No updates. TWH
&&
.SHORT TERM...valid for Sun and Mon...
Water vapor imagery showed moisture moving ESE along the Canadian
border. Observations showed this moisture was a mix of mid and
high clouds. Visible satellite imagery showed stratus E of the
Dakotas` border. This stratus and fog was over SE MT earlier
today. There was some question of the stratus and fog returning to
the SE late tonight. Latest HRRR and other models keep stratus
mostly out of the area through the night so just went with a few
clouds over the far SE.
Ensembles were in good agreement in building a strong ridge over
the area through Sunday. Sunday will be hot and dry with temps in
the low 90s in many areas and RH`s from the teens W to the low 30s
E. Winds will not be overly strong. Models hinted at possible QPF
in the SE Sun. evening due to an inverted trough and low-level jet.
NBM supported this with a slight chance over KBHK so included it
in the forecast. Looking at GFS soundings, which have been
reliable with their RH`s/Td`s, noted that RH recoveries will not
be very good central and W Sun. night. In addition, RH`s looked
very low in these areas on Monday, with a cold frontal passage
from the N expected in the afternoon. Mixing on Mon. will be up to
550 mb in KLVM, and 600 mb in KBIL and KSHR. This will promote
hot, dry and windy conditions, with windy conditions persisting
into Mon. evening behind the front. Given the above, went below
the NBM for RH`s and above it for winds. Used a GFS/ADJMAV model
blend.
An upper trough moves in Monday into Monday night. Noted that
ensembles showed a little uncertainty in the timing/placement of
the trough. There was decent Integrated Water Vapor transport in
the trough area, so there will be moisture, with a chance of
thunderstorms across the area Mon. evening, decreasing overnight.
Noted a lot of shear Mon. night, but not much CAPE. Area was
outlooked for only General Thunderstorms. Temps on Monday will
reach the upper 80s to low 90s with RH`s in the teens central and
W, and in the 20s to low 30s E. If fuels were drier, would be
considering a RFW for portions of the area, but for now, will
continue the headlines in the Fire Weather Forecast. Arthur
.LONG TERM...valid for Tue...Wed...Thu...Fri...Sat...
Tuesday will be dry and cooler behind the cold front that will
move through Monday. Highs will temporarily drop into the 70s, but
by Wednesday highs will be back into the mid to upper 80s. By
Friday another wave will move up into the area. As it does, PoPs
will be increase with some afternoon thunderstorms possible and
temperatures will cool back into the upper 70s to lower 80s.
Showers and afternoon thunderstorms will continue into the weekend
with highs in the 70s. Reimer
&&
.AVIATION...
VFR conditions expected over the next 24 hours. Reimer
&&
.PRELIMINARY POINT TEMP/POPS...
Sun Mon Tue Wed Thu Fri Sat
-----------------------------------------------------------
BIL 059/093 062/092 054/077 052/089 057/088 059/080 054/077
00/U 01/U 41/U 10/U 11/U 22/T 33/T
LVM 051/091 053/088 046/079 046/088 051/086 052/079 048/076
00/U 01/N 31/U 10/U 12/T 44/T 53/T
HDN 056/092 060/090 052/075 050/087 055/088 056/079 052/076
00/U 00/U 41/U 10/U 00/U 22/T 32/T
MLS 058/090 062/087 053/072 049/084 055/086 055/076 051/073
00/U 10/U 30/U 10/U 10/U 12/T 32/T
4BQ 057/091 061/090 052/072 048/084 054/086 055/077 051/073
00/U 00/U 31/U 10/U 00/U 22/T 42/T
BHK 054/087 058/087 051/069 046/081 052/083 051/073 047/069
00/U 21/B 30/B 01/U 10/U 12/T 32/T
SHR 054/092 058/092 052/075 048/086 053/087 054/079 051/076
00/U 00/U 31/U 11/U 11/U 33/T 44/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Quad Cities IA IL
643 PM CDT Sat Aug 31 2019
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 248 PM CDT Sat Aug 31 2019
It`s been a fairly pleasant day across much of the region as we
close out Meteorological Summer. As of 2 pm, temperatures ranged
from 66 in Macomb, to 74 the Quad Cities. Skies featured increasing
cloud cover. Across northern Iowa to southwest Wisconsin, scattered
sprinkles and rain showers were falling as a result of an upper
level shortwave passing over southern Minnesota and northern Iowa.
Thankfully, as our extra balloons for Hurricane Dorian support have
shown, there is plentiful dry air in the low and mid levels of the
atmosphere over our neck of the woods, keeping coverage from
isolated to near nil.
&&
.SHORT TERM...(This Evening through Sunday)
ISSUED AT 248 PM CDT Sat Aug 31 2019
Main short term concerns are chances of precipitation for the rest
of the day and tonight.
All global models are in agreement of the aforementioned shortwave
passing across the region later this evening and tonight. This,
combined with increasing theta-e advection from southerly return
flow, should help generate lift and saturate the dry low levels to
gradually increase rain shower chances as we head through the late
evening into tonight. Think some CAMs like the HRRR are a bit
overdone on precip as they initialized much warmer air and higher
dewpoints than observed, even with clouds being overhead much of the
day. In addition, there isn`t much instability to work with due to
poor low to mid level lapse rates, so chances of thunderstorms are
low. Still expecting some scattered showers and have handled this
with high end chance of POPs for now in the grids. Patchy fog will
also be possible with the increasing moisture at the surface.
Locations that do see rain may have amounts of a few hundreths to a
tenth of an inch, which will be a nice little welcome relief for
those in the moderate drought area. Expecting lows to be a little
warmer than last night with increased cloud cover and dewpoints, and
currently advertise upper 50s along Highway 20, to low to mid 60s to
the south.
Leftover rain showers, clouds and areas of fog will decrease in
coverage from west to east late Sunday morning, with subsidence from
high pressure allowing clouds to break by the afternoon and evening.
Lowered temperatures a little bit from previous forecasts due to
expected prolonged cloud cover, and now advertise highs in the upper
70s to near 80. Regardless, we will be right around normal as we
kick off Meteorological Fall.
.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 248 PM CDT Sat Aug 31 2019
Summer-like heat and humidity now looks likely to a make a brief
come back for the start of the work week, followed by a return to
below normal temperatures and dry conditions. Tuesday`s highs
could push 90 in some locations with dewpoints possibly back in
the 70s.
Sunday night through Monday: Passing high pressure will be followed
by a south to southwesterly low level return flow warm, leading to
lows in the 60s, then highs in the lower to mid 80s.
A strong upper level trough moving across Canada and associated
surface low passing from the Dakotas to Great Lakes will draw much
warmer 850 mb temperatures northeastward out of the western U.S.
ridge into the local area for late Monday into Tuesday. A wedge of
850 mb temperatures progged as high as 20 to 22 degrees C would
support high in the upper 80s to around 90 from I-80 southward,
while the north may at least reach the mid 80s on Tuesday. Brisk
southwest winds at the surface should draw in dewpoints in the upper
60s if not lower 70s, for a July-like feel. Will have low chance
pops across the north from Monday night through Tuesday morning,
where there is a low confidence potential for convection along the
edge of the stronger thetae advection focused further north and
west. SPC has a marginal threat for severe storms north of highway
20 for Monday night, but the main severe weather potential looks to
be further north, where there will be greater shear and better low
level convergence. A better potential for widespread showers and
thunderstorms will arrive with the cold frontal passage in the
afternoon or early evening hours Tuesday.
Surface high pressure and a northwest flow aloft follow for
Wednesday through Friday, bringing back similar conditions as the
past several days with highs in the 70s and low in 50s, and
perhaps even a few upper 40s in the northeast Wednesday morning.
Saturday, there is good model consensus depicting the next cold
front advancing through the area and the next chance for showers
and thunderstorms, which are kept at slight chances for now.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 639 PM CDT Sat Aug 31 2019
The combination of a weak upper level trough and northward
progression of a warm front will generate light rain or sprinkles
this evening, but conditions generally should remain VFR. However
later tonight, weak flow and abundant moisture will support
development of fog and low clouds. MVFR conditions should
prevail, but the risk of IFR ceilings will exist mainly from
around the Quad Cities south and east. By mid-day ceilings and
visibilities across the area should improve to VFR.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Speck
SHORT TERM...Speck
LONG TERM...Sheets
AVIATION...Wolf
Area Forecast Discussion
National Weather Service Hastings NE
651 PM CDT Sat Aug 31 2019
.SHORT TERM...(This evening through Sunday Night)
Issued at 224 PM CDT Sat Aug 31 2019
A shortwave and the associated thunderstorms have largely passed
to the southeast of the area as of early afternoon. The HRRR still
shows a few showers developing over the north which would likely
be diurnally-driven. I kept some low-end PoPs in to account for
this, but I think that any impacts will be minimal.
Tonight, low clouds will move back in. The HREF and SREF still
hint at some fog developing in the area, so I maintained a mention
of patchy fog. Due to the cloud cover, I do not think that it
will be widespread or dense, though.
Sunday will be notably warmer than today as skies slowly clear
out. Highs are expected to return to the 80s for the entire area.
This warmup will occur as ridging expands over the Rockies.
Despite the rising heights aloft, a subtle perturbation is
forecast to move into northern and central Nebraska late Sunday
night, possibly allowing for a few thunderstorms. With 25-35 kts
of effective shear, an isolated strong storm is possible if these
storms develop.
.LONG TERM...(Monday through Saturday)
Issued at 224 PM CDT Sat Aug 31 2019
The main story of the upcoming week is that it will be mostly
dry. Many locations have had excessive rain over the past couple
weeks, so a dry forecast should be a welcome sight for most.
Labor Day should be the warmest day of the week with highs in the
upper 80s and 90s.
A fairly strong front is expected to move through the area on
Tuesday. This will lead to a cooldown and strong northerly winds.
Gusts to 30 MPH are likely. A few showers and storms could also
develop along this front Tuesday night, mainly over southern
portions of the forecast area.
High pressure moves into the area on Wednesday, leading to a
pretty cool and fall-like day. Highs are only forecast to reach
the low 70s for most of the area. Overnight lows are expected to
be in the 50s, and could even dip into the 40s in some areas.
Slightly warmer weather then returns for Thursday and Friday, and
the weather should remain quiet in the local area. Another front
then moves through the area Friday night into Saturday, bringing a
chance for rain and thunderstorms to the area. Deterministic
models disagree on the strength and exact timing of this feature
though.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 649 PM CDT Sat Aug 31 2019
VFR conditions are expected this evening, but we could see the
cloud deck lower as we near dawn with indications that we could
see at least a few hours of MVFR if not IFR conditions around
sunrise or just after sunrise. Ceilings should lift and clouds
scatter out by late Sunday morning.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Wesely
Area Forecast Discussion
National Weather Service Goodland KS
523 PM MDT Sat Aug 31 2019
.SHORT TERM...(Today through Sunday night)
Issued at 145 PM MDT Sat Aug 31 2019
Overview: Modest NW flow aloft will prevail over the Tri-State
area, on the NE-ENE periphery of an upper level ridge centered
over the Desert Southwest/4-Corners.
Today-Tonight: An impressive MCV spawned by widespread convection
early this morning continues to track southeast toward Wichita
early this afternoon. Subsidence in the wake of this feature will
gradually fade as it gains distance and progresses into southeast
KS this afternoon. However, 18Z SPC mesoanalysis data (H7-H4 DPVA,
in particular) suggests that subsidence may persist in assoc/w
another cyclonic feature -- subtle and difficult to pinpoint in WV
imagery, as it may be -- as it progresses southeast through
northwest and north-central KS during the early-mid afternoon.
Aside from differential heating along the slopes of the Colorado
Front Range, little if any forcing can be discerned over the
region today. Although steep mid-level lapse rates and residual
low-level moisture (H85 dwpts ~16C) will likely support moderate
diurnal destabilization (1500-2000 J/kg MLCAPE) by peak heating,
lingering convective inhibition (50-150 J/kg CINH), lingering
subsidence, and scarce/anemic forcing are expected to preclude
convective development over the Tri-State area. With steering flow
from the NW at 15 knots, it`s conceivable that isolated Front
Range convection could propagate downstream into eastern CO (i.e.
Cheyenne county) this evening, though simulated reflectivity
forecasts from recent runs of the HRRR suggest activity will
initiate along/south of Colorado Springs -- and that downstream
propagation would be confined to southeast Colorado.
Sun-Sun night: With little change in the synoptic pattern, expect
conditions similar to (albeit several degrees warmer than) today.
Anemic forcing is anticipated to preclude convective development
over the Tri-State area -- and simulated reflectivity forecasts
via the HRRR and NAM NEST suggest little if any upstream
development will occur in CO/WY/NE during the late aft/eve. With
this in mind, will continue to indicate a dry forecast. It should
be noted -- particularly in NW flow aloft -- that thermodynamic/
kinematic profiles will remain conditionally supportive of
organized severe convection.
.LONG TERM...(Monday through Saturday)
Issued at 105 PM MDT Sat Aug 31 2019
For the extended period the National Blended Model (NBM) is
showing a dry pattern for the work week, with the exception of
Tuesday, for the local area. Followed by another round of
showers/thunderstorms activity next weekend.
For the most part the models do agree with the NBM; however,
Tuesday could end up being dry as well. The models show an upper-
level ridge being the main influence for the region for the
extended. On Tuesday they have a long wave trough moving over the
northern High Plains with an associated surface front. The tail
end of this front should pass through the local area and cool us
off during midweek. The question remains if it will produce any
precip with it. A couple more model runs are needed to know for
sure.
For next weekend it looks like another longwave will follow suit.
Unlike the passing trough/front on Tuesday, the NBM is more
aggressive with this one. However, the models are not in agreement
at all this far out. So staying with the MBM at this time.
At this time, Monday will see highs reach the upper 90s before
dropping into the middle 70s to lower 80s by midweek, after the
front passes through. Follow by a climb into the middle 80s by
Friday. Overnight lows will start out in the lower to upper 60s on
Monday and Tuesday night then drop into the middle 50s for the
rest of the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 518 PM MDT Sat Aug 31 2019
VFR to IFR conditions forecast for the TAFs. Low ceilings will
move in around 6z for both sites as low clouds move up from the
south. The low ceilings will linger until mid to late morning then
shift east of the TAF sites. The lowest ceilings will occur by
12z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...VINCENT
LONG TERM...BW
AVIATION...JTL
Area Forecast Discussion
National Weather Service Wichita KS
657 PM CDT Sat Aug 31 2019
.SHORT TERM...(This evening through Tuesday night)
Issued at 324 PM CDT Sat Aug 31 2019
Morning remnant convection over south central KS continues to wane
as the afternoon progresses, as low level moisture transport is
lost. Latest satellite and 88d mosaic shows a very pronounced meso
vort center (MCV) west of Kingman is currently making its way SE and
will probably trekking into nrn OK for the late afternoon hours.
Lots of available instability for this MCV to work with, as most of
south central KS got worked over by last nights complex of storms.
So think the MCV will continue to drift southeast, possibly leading
to renewed surface based convection as it moves into southern OK
early this evening. Easterly low level flow will lead to dry and
somewhat pleasant evening for most of the area, with any lingering
sprinkles ending by late this afternoon.
Latest RAP shows low level moisture transport again to trys to
increase across the panhandle of OK into SW KS late evening, with
some scattered nocturnal convection expected to develop over wrn and
NW KS. Think
Latest hi-res model solutions are not very bullish on renewed
convection even coming close to the forecast area, keeping any
overnight convection well to the west of the area, as it treks
south where instability axis will be located.
Ridging over the rockies looks to shift further east for Sun and
then into Mon and early Tue. This will lead to warmer temps aloft
moving into the area with dry and breezy southwest downslope flow,
leading to max temps warming back towards seasonal normals.
Ketcham
.LONG TERM...(Wednesday through Saturday)
Issued at 324 PM CDT Sat Aug 31 2019
Both the GFS and ECMWF continue to advertise that a cold front will
ooze into the area for Tue afternoon, and make its way across the
forecast area by Tue night. Not alot of moisture for this front to
work with as it moves south, with both the GFS and ECMWF showing the
chance for some post frontal showers for Tue evening/night across
portions of central KS. Expect cooler temps for Wed/Thu, for central
KS on the north side of the front.
A short warming trend will continue for Fri. Model consensus
supports increasing storm chances and cooler weather once again by
next weekend, as another cold frontal zone oozes south across the
region.
Ketcham
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 645 PM CDT Sat Aug 31 2019
A relatively moist pbl persists across the area and with a light
moist easterly upslope flow progged across the area tonight we
expect to see some pockets of MVFR & IFR cigs and perhaps lowered
visibilities across much of the area. Some low and mid clouds
remain across the area early this evening as the MCV drifts
eastward across the area but with some breaks in the clouds and
increasing radiational cooling, more widespread MVFR & IFR will
likely develop across much of the area after 08-10Z and lingering
into the morning hours on Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 65 87 69 90 / 10 10 0 0
Hutchinson 64 86 69 90 / 10 10 0 0
Newton 64 85 69 90 / 10 10 0 0
ElDorado 64 85 69 90 / 10 10 0 0
Winfield-KWLD 64 86 69 90 / 10 10 0 0
Russell 64 87 69 94 / 10 10 0 0
Great Bend 64 87 69 92 / 10 10 0 0
Salina 65 86 70 92 / 10 10 0 0
McPherson 64 84 68 90 / 10 10 0 0
Coffeyville 65 86 69 90 / 20 10 0 0
Chanute 63 85 69 89 / 20 10 0 0
Iola 63 85 69 89 / 20 10 0 0
Parsons-KPPF 64 85 69 89 / 20 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...BDK
LONG TERM...BDK
AVIATION...MWM
Area Forecast Discussion
National Weather Service Lincoln IL
913 PM CDT Sat Aug 31 2019
.SYNOPSIS...
Issued at 300 PM CDT Sat Aug 31 2019
Scattered showers or sprinkles will affect mainly the northern
half of central Illinois tonight, primarily north of I-72. Skies
will remain cloudy, as low temperatures drop into the lower to
middle 60s. Patchy fog will be possible later tonight. While an
isolated thunderstorm can not be ruled out this evening, no severe
storms are expected. Shower chances will linger on Sunday, mainly
east of I-55, as high temperatures climb into the upper 70s to
lower 80s.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 300 PM CDT Sat Aug 31 2019
The warm front positioned south of central Illinois is making very
slow progress back to the north, which was previously advertised
in the high res guidance. It has instead remained nearly
stationary along I-64. North of the front, scattered showers or
sprinkles have bubbled up from time to time, with no concentrated
focus for precip evident in the satellite or radar images. Have
therefore covered the evening portion of the forecast with a broad
brush of slight chance PoPs for showers. An isolated thunderstorm
could develop late this afternoon and early this evening, but
instability has not increased under the veil of clouds across the
area. So any storms would be short lived.
After midnight tonight, an upper level trough will progress into
Illinois, bringing a wave of positive vorticity advection, and
forcing for precip. The affects of the that trough and shortwave
will continue Sunday morning, and linger east of I-55 in the
afternoon. The precipitation should remain scattered in general,
with rainfall amounts remaining less than a quarter inch from
tonight through Sunday afternoon. Despite the cloud cover, high
temps are still expected to rise into the upper 70s to lower 80s.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 300 PM CDT Sat Aug 31 2019
Dry conditions are expected to begin Sunday night, and continue
into Tuesday as high pressure settles in across the area. Upper
level ridging will support a noticeable warm-up Labor Day into
Tuesday. Highs on Monday should reach to near or just above normal
in the mid 80s, with Tuesdays highs potentially reach the upper
80s to around 90. Humidity levels will become uncomfortable as
well, especially on Tuesday, as southerly winds boost surface
dewpoints into the lower 70s. Heat index readings on Tuesday
afternoon will climb toward the middle to upper 90s in some
locations.
A cold frontal passage late Tuesday afternoon and evening will
bring an airmass change, along with some scattered showers and
storms, primarily Tuesday evening. The precip chances will be more
confined to the NE half of central Illinois, generally NE of
Peoria to Lincoln to Mattoon. The front will be relatively
moisture starved, so rainfall production will be on the light
side from any showers that do develop.
Cooler and drier air will settle into the area for Wednesday and
Thursday, as high temps return back down into the 70s. Thursday
looks to be the cooler of the two days with most areas topping out
in the mid 70s. Rain looks to hold off the rest of the week
through Saturday, with the storm track remaining north of our
area. A slight warmup on Friday toward 80 will be short-lived, as
highs Saturday pull back into the low to mid 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 913 PM CDT Sat Aug 31 2019
Very light precip is moving across the CWA this evening and will
continue to do so during the overnight hours as well. Will keep
pops low given how light it is. Based on HRRR hires model, could
be most light precip from late tonight through early tomorrow
morning. Looks like all precip will be showers or sprinkles and
not expecting any storms. Will be making these adjustments and
sending new forecast shortly.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Shimon
SHORT TERM...Shimon
LONG TERM...Shimon
AVIATION...Auten
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1104 PM EDT Sat Aug 31 2019
.UPDATE...
Issued at 1105 PM EDT SAT AUG 31 2019
It`s been an interesting evening watching some strong storms
develop to our east and to our west, but not impacting our CWA.
The one just to the west of our northern counties was quite
impressive, producing golf ball sized hail in Harrison county
before finally dissipating as it neared our Bath county border.
One small shower developed over Harlan County in the last hour, a
bit unexpected, but has since dissipated as it moves NW. Made
several adjustments since the previous update, first to reduce
pops to isolated across the remainder of the CWA for the rest of
the evening based on the current radar trends, and then to
increase the pops in the SE where the Harlan County shower
developed. Also have tweaked the temps and winds a bit to make
sure they line up with the latest observations. All updates have
been published and sent to NDFD/web. New zones and HWO have been
sent out to remove evening and storm wording.
UPDATE Issued at 737 PM EDT SAT AUG 31 2019
Forecast was in pretty good shape. So far we haven`t had any
storms pop up across our CWA, though there is some storms around
us, and a couple that may still make their way into our northern
CWA from the west. Since Chance pops were currently forecast for
the northern CWA, went ahead and reduced those to isolated with
the lack of ongoing convection. Blended into the chance pops in
place in the northeast, though if the radar trends continue, will
likely drop these to isolated as well. Otherwise, main updates
were to adjust the near term temp, dew point, and wind forecasts
to make sure they were on track with the current observations. All
updates have been published and sent to NDFD/web.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 435 PM EDT SAT AUG 31 2019
A weak mid level shortwave is moving across the Lower OH Valley at
this time in westerly flow aloft. Mid and upper level ridging is
centered near Bermuda and extends into the southeast Conus with
another center of ridging near the Four Corners region. The axis
of weak troughing extends south through the MS Valley. Another
shortwave trough is upstream and moving through the Central
Plains. A quasi stationary and weakening sfc boundary that is
located in the vicinity of the Mountain Parkway and is expected to
remain in nearly the same location and dissipate through the
period. Cumulus has developed across the region, but the most
agitated cumulus is over Central KY with recent development of a
shower northwest of LEX.
MLCAPE is analyzed in the 500 to 1500 J/KG range from Hal
Rogers/KY 80 corridor north. 1000 to 1500 J/KG MLCAPE is analyzed
from along Mtn Parkway corridor and north. Mid level lapse rates
are on the meager side, though low level lapse rates are currently
steep in the 8C to 9C range. DCAPE is currently analyzed in the
1000 to 1500 J/KG range. Bulk shear is on the order of 25 to 30KT.
Gusty to possibly damaging winds will be the primary threat from
any thunderstorms. As the weak shortwave moves east, some
additional development should occur in the vicinity of the
boundary. Convective allowing models such as the HRRR support this
with development near or just north of the Mtn Parkway corridor
in the instability axis. With the loss of daytime heating, the
chances for convection will diminish within 1 to 2 hours past
sunset. With low and mid level clouds diminishing overnight and
weak pressure gradient across the region, valley fog should
develop.
Sunday into Sunday night, another shortwave trough axis should
approach the are on Sunday while the weakening boundary remains
across the area. Some isolated to possibly scattered convection
should develop during peaking heating, mainly in the northern
portions of the area. Otherwise, temperatures will again be warm
and above normal. Warm and despite rainfall during the past week,
the recent dryness over the past four weeks and relatively low
soil moistures highs should again be warmer than MOS guidance
guidance and NBM highs appear generally on target with some minor
adjustments in a couple of spots. Any convection should diminish
by a couple of hours past sunset on Sunday night with lows
averaging in the mid 60s.
.LONG TERM...(Monday through Saturday)
Issued at 419 PM EDT SAT AUG 31 2019
The extended portion of the forecast begins on Monday with a strong
ridge in place over the western CONUS. Also, at the beginning of the
extended, a decent shortwave trough will cross the OH Valley. This
trough will dig south enough to bring a cold front across Kentucky.
Closer to the surface, model soundings for Monday afternoon and
evening show weak capping and instability around 2500 J/KG. Thus
have put some slight chance pops in for Monday afternoon and into
the evening. With pops in the previous forecast and the operational
models continuing to show QPF over the area, will decide to keep the
pops in the forecast despite the dry forecast from the NBM.
According to the trends in the model soundings, the main threat for
Monday evening will likely be some strong wind gusts.
After the first wave ejects east, a second strong shortwave crosses
the crest of the ridge over the western CONUS and into the northern
Plains. Shortwave ridging behind the previous wave will keep dry
conditions over eastern Kentucky for Tuesday. The second mentioned
shortwave will track into the the Great Lakes for Wednesday and
will bring a second cold front into the region. Once again, with
the ridge out west rebound in strength, the trough will dig south
into the OH Valley again bringing a cold front through the area
again. MU CAPE values for this event will range into the 2000 to
2500 J/KG range with once again, weak capping to the north. The
initial forecast from the NBM came in with some slight to low chance
pops so will keep this forecast in place for Wednesday afternoon.
Temperatures through these first 3 days of the extended will be in
the middle to upper 80s. Did lower highs for Tuesday and Wednesday
as the EC and GFS MOS were at least 2 degrees below the NBM
solution. Strong surface high pressure will settle into the area
behind the previous front with dry weather expected through the rest
of the extended. Highs for Thursday and Friday will be significantly
cooler with upper 70s to around 80 expected. Some locations to the
north may actually be cooler.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 743 PM EDT SAT AUG 31 2019
A quasi stationary boundary located in the vicinity of the Mtn
Parkway should be a focus for isolated storm potential through
about 2Z this evening. Based on current radar trends, while there
are no storms currently in the VC of the TAF sites, there are some
across the northern Bluegrass moving eastward. Kept VCTS at KSJS
since they will have the best likelihood of seeing these or any
other developing storms over the next couple of hours. Otherwise,
remaining TAF sites should not be affected. Outside of brief MVFR
or IFR in any thunderstorms, VFR should prevail through the
period. However, some river valley fog is again be expected
between about 6Z and 13Z. Winds will be light and variable outside
of any thunderstorms.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...JP
LONG TERM...DJS
AVIATION...JMW
Area Forecast Discussion
National Weather Service Blacksburg VA
1008 PM EDT Sat Aug 31 2019
.SYNOPSIS...
Mostly dry weather and seasonal temperatures are expected for
the majority of the Appalachians and central mid Atlantic
region through early next week as high pressure remains over
the area. However, it remains to be seen if Hurricane Dorian
will track far enough westward to have any effects on our
weather later next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 1000 PM EDT Saturday...
WSR-88D radars showed cluster of showers and thunderstorms over
the Greenbrier Valley and Alleghany Highlands. Overall trends
was for slow weakening and a gradual north-northeast drift. A
bulk of the Hi-Res, ConsShort, SREF, and HRRR diminish the
areal coverage of the precipitation enough after 06Z/2AM to
remove any remaining probability of precipitation after that
time. Only minor changes to minimum temperatures based on
current temperature trends and the latest LAV/MAV guidance.
High pressure wedging down from New England will continue to
push the frontal boundary through the region. This will generate
some low clouds and fog late tonight into early Sunday morning.
Anticipate Sunday will remain dry for the vast majority of the
area with maybe an isolated shower well north if Interstate 64.
Expect lows tonight a few ticks warmer than last night with
low/mid 60s east of the Blue Ridge and generally mid 50s/lower
60s to the west. Highs in the wedge on Sunday will be cooler as
well with middle 80s east to mid 70s/near 80 west.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 300 PM EDT Saturday...
No significant weather hazards expected for our forecast area
during the short term. A weak upper level trough over the region
Monday is forecast to lift northeast and off the New England
Coast, subsidence increasing Tuesday in advance of the tropical
cyclone to our southeast. There is a slight chance for a
shower/thundershower over the mountains Monday, associated with
the trough, but increasing subsidence should put a lid on things
by Tuesday with little or no rain anticipated.
Temperatures Monday are expected to reflect the seasonal norm with
Highs ranging from the 70s mountains to mid 80s piedmont, and Lows
in the 50s mountains to the mid 60s piedmont. Tuesday is expected
to be a few degrees warmer...more sun and subsidence contributing to
the warming.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 315 PM EDT Saturday...
Upper ridging over the southern Rockies and into the southern
Plains, and western Atlantic Ocean, will help to funnel Hurricane
Dorian northward near/along the Atlantic coast Wed-Fri. As troughing
in the northern stream swings through the Great Lakes Wednesday, it
will begin to tug Dorian northeastward near/along the Carolina coast
as additional height falls push through Ontario by Friday. This
suggests the overall impact to our forecast area from Dorian will be
limited, with the end result favoring a dry forecast as opposed to a
tropical deluge. That said, will continue to entertain at least a
chance for some rain associated with Dorian in our far eastern CWA
(east of Highway 29) to account for potential changes in the
forecast track. In addition, the trough which is expected to move
across the Great Lakes Wednesday, will also provide as a lifting
mechanism for showers, so the shower threat may not be just limited
to the eastern CWA, and will entertain at least low chance pops
areawide for Thursday to account for both systems (the trough and
the Hurricane). After Thursday, think the trough will move to the
coast and limit the westward influence from the tropics, confining
the rain threat mainly to the Tidewater region.
The warmest temperatures are expected Wednesday, ahead of the trough
and within the subsidence region in advance of Dorian. Temperatures
are expected to top out in the 80s mountains to near 90 in the
piedmont. The trough should introduce a relatively cooler/drier
airmass for the end of the week, highs/lows retreating to the
seasonal norm, or even a few degrees below that pending cloud
cover.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
As of 743 PM EDT Saturday...
VFR conditions will prevail at the taf site this evening into
tonight with isolated sub-VFR conditions in showers and
thunderstorms for next couple of hours. The best low level
convergence is location north of Interstate 64.
Convection will dissipate this evening with loss of heating.
The front will push southward overnight as high pressure wedges
down from New England. This will bring a surge of low level
moisture into the region on easterly flow and generate some
stratus/fog toward daybreak. The models are showing the richest
moisture in the northwestern portions of the forecast area.
Anticipate a slow improvement in flight conditions by late
morning/early afternoon Sunday. VFR conditions will
return to all taf sites Sunday afternoon.
Winds will generally be light with no significant impact to
aircraft operations expected.
Medium conditions in ceilings, visibilities and winds during
the taf period.
.Extended Aviation Discussion...
Generally VFR conditions are expected through much of next week,
outside any late night fog and isolated showers. Dorian appears
to be staying away from us in the near future, but forecasts
could change. Aviation interests should monitor conditions along
the southeast through next week.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...MBS/WP
NEAR TERM...AMS/MBS
SHORT TERM...PM
LONG TERM...PM
AVIATION...KK/MBS