Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/09/17
Area Forecast Discussion
National Weather Service Charleston SC
1003 PM EDT Tue Aug 8 2017
.SYNOPSIS...
A front will linger nearby through Thursday before lifting back
north. High pressure will rebuild Friday through early next
week. A cold front could approach the area next Monday or
Tuesday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 10 PM: Stratiform rain and isolated thunderstorms
continued across SE GA and across the GA waters. PoPs will
remain likely across the area of rainfall. To the north, PoPs
will be reduced to SCHC. I will maintain cloudy to mostly cloudy
conditions through the night, expecting debris clouds followed
by low stratus late tonight.
As of 8 PM: Deep convection has pushed over the Atlantic, with
isolated thunderstorms near the mouth of the Altamaha River.
Based on the radar and satellite trends, I will update the
forecast to reduce PoPs through the late night hours. PoPs will
begin to increase during the pre dawn hours, primarily just
offshore near the land breeze.
Previous Discussion:
Remainder of the afternoon: The combination of weak upper
forcing, deep moisture and a web of mesoscale boundary
interactions will keep numerous showers and tstms going over our
SC zones. Rain will be heavy at times with localized flooding
expected will training convection and in association with
strongest storms. The latest HRRR model runs suggest the brunt
of the heavier rains will slide offshore between around 22Z or
23Z at the latest. Much of this rain was falling during the low
tide cycle along the coast, but rainfall rates were still
impressive and will need to be monitored.
Tonight: High resolution models continue to show scattered convection
over southeast GA early this evening, likely decreasing after 01Z
with the loss of diurnal heating. Across SC, showers and storms are
expected to be mostly offshore at dusk to the north of the Savannah
River, leaving areas of lighter rains with a few pockets of convective
rains still possible.
A weak cold front should drift over the forecast area tonight while
deep moisture remains intact. A late night short wave in the
mid levels may keep some scattered rains/showers around late in
the night. We maintained chance POPs many areas after midnight
which maintained good persistence with the previous forecast.
Low temps will be in the lower to mid 70s and with the frontal
zone in the vicinity, there could be patches of low clouds and
patchy fog over inland areas, mainly north of I-16.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A relatively wet pattern is expected. A weak mid-level trough will
remain over our region while several shortwaves traverse the trough.
The shortwaves on Wednesday and Thursday might be stronger and more
noticeable to our weather. At the surface, a stationary front will
linger nearby through Thursday, then transition into a warm front
and rapidly move northward Thursday night into Friday. Deep moisture
is in place with PWATs above 2.0", perhaps getting up to 2.3" at
times. Lift should be decent due to the vicinity of the front,
enhanced by cold pool boundaries. Numerous showers are expected,
with the greatest potential being in the afternoon and evening.
Instability is moderate for this time of year and models show it
increasing into Friday, especially during peak heating. The overall
risk of severe weather is low. Heavy rain appears to be the main
threat, especially due to weak steering flow. Local flooding is not
out of the question, especially in storms that train. Cloud cover
and shower coverage should keep highs several degrees below normal.
Lows will be in the lower to mid 70s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Weak upper ridging over the weekend will result in a slight increase
in temperatures and a more typical summertime convection pattern
favoring afternoon and evening hours.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Debris cirrus should gradually decrease through the rest of the
overnight hours. Forecast soundings and LAV indicate that MVFR
stratus will gradually develop with the loss of the high cloud
deck. Cloud decks should reach the lowest point during the hours
around sunrise, highlighted with a TEMPO from 10z to 14z.
Convection should expand during the late morning to early
afternoon hours.
Extended Aviation Outlook: Showers and tstms may occasionally affect
the terminals, with temporary visibility restrictions the primary
concern.
&&
.MARINE...
Tonight: Synoptic winds have decreased today and mainly light
winds are expected tonight, becoming variable late as a weak
front drops in. The main hazards tonight will be scattered to
numerous showers and storms producing frequent cloud to water
lightning strikes and heavy rains with low visibilities.
Wednesday through Sunday: A front will linger nearby through
Thursday before lifting back north. Atlantic high pressure will
become the more dominant feature Friday through the weekend. A weak
pressure gradient will result in winds at or below 10 kt with weak
afternoon sea breezes close to the coast. Conditions may be
favorable for waterspouts Wednesday morning with light and
variable winds and deep moist vertical profiles.
Atlantic high pressure will remain the dominant marine feature
Wednesday through Sunday, resulting in south to southwest winds
at or below 10 kt and weak afternoon sea breezes along the
coast.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...NED
SHORT TERM...MS
LONG TERM...MS
AVIATION...MS/NED
MARINE...MS
Area Forecast Discussion
National Weather Service Dodge City KS
707 PM CDT Tue Aug 8 2017
...Updated Aviation Section...
.SHORT TERM...(This evening through Wednesday)
Issued at 337 PM CDT Tue Aug 8 2017
Weak shortwave disturbance evident in satellite imagery moving
east through the central High Plains early this afternoon. A
persistent area of widely scattered light rainshowers was moving
through west central and northwest Kansas, associated with this
wave. Additional thunderstorms were developing over the central
Colorado mountains. The atmosphere over western Kansas remains
fairly stable today with the best instability back along the
Colorado Front Range.
The HRRR has been pretty consistent in gradually moving the area
of scattered showers east through western Kansas this evening.
Am not expecting much in the way of thunder from the showers this
evening and it appears that any thunderstorms moving off the Front
Range this afternoon will diminish or head southeast into northeast
New Mexico this evening. Later on tonight, another weak wave will
move out into the central High Plains. All the convective allowing
models are showing scattered showers redeveloping after midnight
over western Kansas and moving into central Kansas Wednesday
morning. Will keep the high chance to likely pops going across the
area later tonight through midday Wednesday. Models show
instability increasing somewhat overnight with this system so will
also keep a mention of isolated thunder as well.
High temperatures on Wednesday will be dependent on cloud cover
and precipitation. Have gone a little cooler toward central Kansas
Wednesday afternoon where clouds/precip will linger. Highs should
be several degrees warmer in far southwest Kansas where Elkhart
should hit the mid 80s or so.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 336 PM CDT Tue Aug 8 2017
West to northwest flow flow aloft will persist across the central
High Plains through the end of the week with progressive waves
crossing the northern/central Plains. A stronger shortwave trough
and associated front moves through the northern and central
Plains on Thursday afternoon and evening. Instability increases
across southwest Kansas ahead of this system. Thunderstorms should
develop across the High Plains and develop into an MCS as they track
southeast across western Kansas Thursday evening. Current Superblend
develops likely to categorical pops which looks reasonable.
Friday should be a relatively quiet day weather wise as the
disturbance moves east of the region and the cold front extends
across Oklahoma into the Front Range. There should be additional
chances for thunderstorms through the weekend. By early next week
upper level ridging begins building toward the northern and
central Plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 705 PM CDT Tue Aug 8 2017
Nocturnal showers and isolated thunderstorms are expected
especially after 06z. Showers are expected to affect terminals at
least through the mid morning hours Wednesday (roughly 15z) and
perhaps later than that. By morning, ceiling is expected to fall
into the MVFR category.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 63 80 64 88 / 50 60 40 20
GCK 62 81 63 86 / 40 40 30 20
EHA 62 86 63 87 / 50 20 40 30
LBL 62 84 65 89 / 40 40 40 30
HYS 64 77 63 84 / 60 60 40 20
P28 65 81 67 90 / 30 40 40 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gerard
LONG TERM...Gerard
AVIATION...Umscheid
Area Forecast Discussion
National Weather Service Duluth MN
720 PM CDT Tue Aug 8 2017
.UPDATE...
Issued at 720 PM CDT Tue Aug 8 2017
Please see the 00Z Aviation Discussion below.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 246 PM CDT Tue Aug 8 2017
Showers and thunderstorms will continue and then linger into this
evening across the Arrowhead, far northern Minnesota, and far
northern Wisconsin, from daytime heating and a stalled front over
far northern Minnesota. Additional showers are possible over far
northern Minnesota and the Arrowhead late tonight when low
pressure approaches from the west, and the elevated lifts north
and east as a warm front. The low-level jet will be somewhat weak,
but it could develop showers north of the elevated warm front.
There will be very light wind flow across the Northland tonight,
and somewhat high relative humidity in some areas. Patchy fog is
forecast for some areas. Overnight lows should be in the lower and
middle 50s.
An mid/upper level trough and accompanying surface low reflection
will dig into the Dakotas late tonight and then begin moving into
the Dakotas/Minnesota border region by late in the day Wednesday.
This low will bring modest large-scale forcing for ascent across
the Northland. Southerly flow ahead of the low will bring greater
atmospheric moisture into the region, with precipitable water
values increasing to about 1.25 inches. The forcing and daytime
heating is expected to result in scattered showers and some
thunderstorms across most of the Northland by the middle or late
afternoon. There will likely be about 250 to 750 J/kg of mixed
layer CAPE, but only about 10 to 20 knots of 0 to 6 km deep layer
wind shear for most areas. The lack of wind shear will make it
difficult to develop organized updrafts, but cannot rule isolated
storms capable of small hail in this environment.
Broken/overcast cloud cover Wednesday will limit heating, despite
the warm southerly flow. Also, a lake breeze response to
approaching low pressure will bring even cooler conditions to the
Lake Superior shoreline. Highs will range from the upper 60s and
low 70s near Lake Superior to the middle 70s inland.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 246 PM CDT Tue Aug 8 2017
The long term models are coming into better agreement Wednesday
night through Thursday night. The GFS/ECMWF agree now that the
upper level will feature a short wave trof with a potent vort max
moving through the base of the trof crossing the forecast area. A
closed mid level circulation is noted with its surface low
reflection vertically stacked with the mid level circulation. The
result is periodic showers and thunderstorms affecting the
forecast area. The precipitation will diminish from west to east
Thursday night as this system moves off to the eastern Great
Lakes. Minor differences creep into the forecast on Friday. Even
through the closed mid level circulation remains over the eastern
Great Lakes, the ECMWF/GEM are dry and the GFS generates a small
swath of QPF over the central part of the region. Used a blend
which leaned heavily on the GFS. The closed circulation finally
moves off to the east Friday night allowing a more northerly flow
aloft. Meanwhile, high pressure becomes entrenched at the surface
and is in charge through Sunday morning. An upper long wave trof
begins to drop through the region on Sunday afternoon to varying
degrees. A blend is used here for attempting to time in some
showers and storms Sunday afternoon over the Arrowhead. The trof
departs Sunday evening ending the precipitation as the high
regains control. The next trof arrives Monday afternoon with the
next chance of showers and storms over the northeast portion of
the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 720 PM CDT Tue Aug 8 2017
A cold front will stall across northern Minnesota tonight, while
an area of low pressure develops across the central Dakotas. The
low will move eastward tonight and on Wednesday into the eastern
Dakotas/western Minnesota. Due to the front and diurnal heating,
showers and storms will persist until approximately 03Z per the
last several HRRR runs. Ceilings will remain around 5000 to 10000
feet. Patchy fog is possible at HIB late tonight due to relatively
clear skies, recent precipitation, and light winds. Have
visibilities going down to IFR, however lower will be possible at
times.
As the low lifts into the eastern Dakotas/western Minnesota on
Wednesday, expect scattered showers and storms to develop across
the region. Ceilings should remain around 5000 to 8000 feet per
the latest guidance. In addition, visibility reductions will be
possible, especially when/if a shower or storm moves across a
terminal. Otherwise, expect VFR conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 74 57 66 / 20 50 70 60
INL 54 74 55 70 / 20 60 60 50
BRD 58 73 58 70 / 0 70 70 50
HYR 57 76 58 69 / 10 60 70 60
ASX 57 76 58 69 / 30 40 70 70
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...WL
SHORT TERM...Grochocinski
LONG TERM...GSF
AVIATION...WL
Area Forecast Discussion
National Weather Service Hastings NE
646 PM CDT Tue Aug 8 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 244 PM CDT Tue Aug 8 2017
Extensive cumulus with a few showers have developed across the
area this afternoon. This will likely continue into the early
evening, although precipitation will be fairly localized, and most
locations will likely stay dry. An isolated rumble of thunder is
possible as well, although there shouldn`t be anything strong.
Tonight into tomorrow morning, additional thunderstorms will move
through the area in association with the leading edge of a
shortwave moving out of Canada. The NAMnest and HRRR both look to
keep the bulk of this activity across the southern half of the
CWA. I`ve trended the forecast in this direction, although PoPs
may still be too high from the tri- cities northward.
Tomorrow, a cold front moves through the area, bringing us a better
chance for rain and thunderstorms. Depending on how much we clear
out, there could be potential for a few strong storms. That said,
this is looking marginal at best with the GFS showing 1000-1500 J/kg
of CAPE. As such SPC has removed the "marginal" risk from all but
the northern edge of the CWA.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 244 PM CDT Tue Aug 8 2017
Rain and thunderstorm activity will gradually push southeastward out
of the area Wednesday night into Thursday morning. This will pave
the way for another quick-moving wave to bring rain chances back
into the area Thursday afternoon through the overnight. It is my
first forecast shift in a few days, but it appears that the PoP
grids have trended farther southwest with this wave, leaving only
slight chances for rain for most of the area. Despite the lower
PoPs, a strengthening upper level jet will make for increased
deep layer shear...on the order of 40 to 50 kts. Therefore a few
strong to marginally severe storms are possible, mainly southwest
of the tri-cites.
This cycle repeats itself with more disturbances moving through
the area Friday night into Saturday and again Saturday night into
Sunday. The model consensus is much more optimistic about PoPs
during these time frames than it is Thursday into Friday morning.
The main upper wave finally pushes through the area Sunday night
into Monday, possibly allowing us to briefly move back into a drier
pattern for early next week.
Overall, there isn`t much too look at from a severe-weather
perspective beyond Thursday. Like the past several days, high
temperatures will only reach the upper 70s to low 80s, which will
severely limit our instability. Given the time of year, severe
weather isn`t completely out of the question, but does look
relatively unlikely.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 642 PM CDT Tue Aug 8 2017
As a cold front approaches, we will stand a better chance at
showers/thunderstorms in the area. Instability will not be that
high, so severe probabilities will be low. CCL levels suggest that
we could have MVFR ceilings at least at some point Wednesday.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Green Bay WI
1032 PM CDT Tue Aug 8 2017
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 245 PM CDT Tue Aug 8 2017
Skies were partly cloudy across the region this afternoon.
Temperatures were mainly in the upper 70s to middle 80s.
For the remainder of the afternoon into this evening,
will need to watch enhanced cumulus field across northern
Minnesota and across interior sections of Upper Michigan.
a few showers have popped up across interior sections
of Upper Michigan. Current thoughts is that any shower
activity that does develop over the remainder of the
afternoon should stay north of the area along the lake
breeze boundary. Attention then turns to shower activity
developing across northern Minnesota. Some of this activity
could move into far north-central and far northeast Wisconsin
late this afternoon and evening. This was indicated the NAM12
and several runs of the HRRR. Have small chances of showers
to account for this activity. After midnight, the HRRR continues
to show some light shower activity just north of the area. Will
have dry conditions for this period. Current min temperatures
looked reasonable and only small changes made.
On Wednesday, partly cloudy skies will prevail. There will be a
small chance of showers across the far north during the morning
and then a chance of showers and storms north and west of the
Fox Valley Wednesday afternoon. Severe weather is not anticipated.
No significant changes to high temperatures on Wednesday.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 245 PM CDT Tue Aug 8 2017
The upper trough moving across the northern Plains into the
western Great lakes will produce a surface cyclone that will move
slowly across Wisconsin Thursday and Thursday evening. The slow
movement and modest low level moisture should be able to produce
as much as an inch of rain in some places. Rivers and streams are
somewhat high for this time of the year, but should be able to
handle that amount.
The severe potential looks small but non zero. The upper dynamics
are pretty good, but instability may be held down by clouds. Mid
level winds are modest, and there is some directional shear. Wet
bulb zero heights are fairly high, so the main threat would be
strong winds.
The upper trough exits Friday, but there will likely be some showers
in the briefly cyclonic flow behind it. Another broad upper trough
will move across Wisconsin Saturday and Sunday, but it will be
accompanied by high pressure at the surface. Scattered afternoon
showers would not be out of the question, but it looks like it would
be mostly dry.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1027 PM CDT Tue Aug 8 2017
VFR conditions are expected to continue at the TAF sites through
most of the period. Showers associated with a weak cold front
should weaken across far northern WI early in the TAF period.
Patchy fog may develop near the stalled frontal boundary over the
far north later tonight, but suspect the fog will remain north of
RHI. On Wednesday, there will be a chance of showers and
thunderstorms over the northwest part of the forecast area,
including the RHI TAF site, in the late afternoon and early
evening. Showers should increase across north central and central
WI later in the evening, as an upper level disturbance approaches
from the west. MVFR conditions may accompany any heavier showers
or storms.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....Eckberg
LONG TERM......RDM
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Houston/Galveston TX
902 PM CDT Tue Aug 8 2017
.DISCUSSION...
For the evening update, we have added Galveston County (mainly for
the Bolivar Peninsula area where some heavy rainfall fell late this
afternoon through early this evening) to the Flash Flood Watch.
There is some potential for additional shower and thunderstorm
development overnight closer to the center of the slow moving low that
we have been dealing with for the last couple of days. Hard to pinpoint
exactly where the heaviest rains might fall, but best potential looks
to maybe be setting up between the Houston and Beaumont areas where
WPC upgraded their slight risk to a moderate risk in their Day 1 Excessive
Rainfall Outlook. Any heavy rains falling on already saturated grounds
will quickly lead to flash flooding. 42
&&
.PREV DISCUSSION... /ISSUED 717 PM CDT Tue Aug 8 2017/
AVIATION...
Widespread scattered showers and thunderstorms are continuing to
spiral around the area of low pressure currently centered just east
of IAH. Expecting most precip to diminish for a short period of time
this evening around 23-01Z, resulting in a lull in showers and
thunderstorms until the late evening hours. Short term guidance such
as the HRRR and ARW indicate redevelopment for the northern TAF
sites around 02Z, shifting a line of convection southeastward
through the IAH/HOU/SGR region by 09Z. Additionally, a second band
of showers and thunderstorms pinned along the coast also redevelops
around 07Z and pushes northward impacting LBX and GLS through the
afternoon.
Although there will definitely be the potential for scattered
showers and thunderstorms circulating around the area of low
pressure overnight, there is less confidence in how this low
propagates. If the center of the low moves further eastward, we
could see a shift in the rainfall more to the east, resulting in
less impacts to all TAFs sites. Short term guidance has appeared to
be sliding the precip further east in the most recent runs and
forecasting the center to move eastward, so will have to continue to
monitor to see if this trend continues.
Otherwise, VFR conditions through late evening, with a MVFR deck
expected to develop around midnight and hold through early morning.
Overnight, winds will vary in direction around the center of the
low, but should remain less than 5 kts inland and between 5-10 kts
along the coast.
Hathaway
PREV DISCUSSION... /ISSUED 319 PM CDT Tue Aug 8 2017/
DISCUSSION...
The main item of concern for this evening through Wednesday
morning is the possibility of heavy rainfall mainly over the
eastern areas. To that end, have continued the flash flood watch
for Harris, Chambers, Liberty, Montgomery, Polk and San Jacinto
counties through 8:00 AM Wednesday. A consensus of the models are
fitting the location of the MCV (mesoscale convective vortex)
which was near San Jacinto County at 2:30 PM. Because the area of
the heavier rainfall looks to occur mainly from Chambers County
northward, have dropped the watch for Waller and Fort Bend
counties.
From an overall perspective, a weakness in the upper level high
pressure ridge will likely cause the MCV to meander a bit. Most
models show the feature drifting southeastward and turning
northward tonight. If the MCV shears apart, another MCV could
develop if another mesco-scale convective complex forms tonight.
With all the uncertainty, confidence in the model solutions are
moderate at best. WPC 50th percentile showed heaviest rainfall
possible across and east of Chambers, far eastern Harris and
Liberty counties. Higher resolution models then have potential
into San Jacinto and Polk counties. Best chances for showers and
thunderstorms will be over the eastern and coastal counties on
Wednesday.
For Thursday scattered coverage of showers and thunderstorms is
expected. As the upper level ridge builds overhead from the west,
only slight chances are expected Friday through the weekend and
into early next week. The building ridge will lead to less cloud
coverage and increasing daytime temperatures into the mid 90s
over the inland locations. Moisture from the Gulf could also
increase and lead to an increase in the heat index to between 105
and 107 over the weekend.
MARINE...
Scattered showers and thunderstorms are possible once again tonight
given the proximity of the upper level disturbance over SE TX. Best
rain chances will be over the bays and nearshore waters. Otherwise,
winds will remain light and from the SW overnight. Winds are expect-
ed to become more SE and slowly strengthen by late tomorrow evening
as this system moves out of the area. This increasingly moderate on-
shore flow will be coupled with the possibility of increased swells
from Franklin as it moves into the Bay of Campeche. Seas could
range from 4-6 feet by Weds night through Thurs before gradually
tapering off by this weekend. Rain chances should also be
decreasing through the rest of the week with progs of an upper
level ridge building in from the west. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 74 90 75 96 76 / 20 30 30 30 10
Houston (IAH) 75 90 77 92 77 / 50 50 20 40 10
Galveston (GLS) 79 88 81 88 82 / 70 50 40 40 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch until 8 AM CDT Wednesday for the following
zones: Chambers...Galveston...Harris...Liberty...
Montgomery...Polk...San Jacinto.
GM...NONE.
&&
$$
Discussion...42
Aviation/Marine...08
Area Forecast Discussion
National Weather Service Lubbock TX
623 PM CDT Tue Aug 8 2017
.AVIATION...
Low clouds are breaking up across the area, and their return is
questionable. Some low level moisture off the deck will persist,
but models are leaning toward keeping skies scattered and if they
return they are likely to be just above the MVFR cutoff. Will run
optimistically this TAF cycle and monitor through the evening. The
other issue this evening is TS chances. Scattered TS northeastern
New Mexico are unlikely to make it much farther east than the
TX/NM state line. However, models are picking up on TS in
southeast Colorado staying alive through the night and moving
toward the South Plains area around 12z Wednesday. This would be
abnormal, so have trended conservatively and left mention out as
well.
&&
.PREV DISCUSSION... /issued 338 PM CDT Tue Aug 8 2017/
DISCUSSION...
Low clouds have been slow to erode on the Caprock today and have
kept temperatures mired in the 70s, while the Rolling Plains have
warmed into the 80s. The cool temperatures have also kept the area
quite stable, and we`ve seen only a few very light rain showers
periodically form across the western South Plains. Satellite
imagery shows some showers and thunderstorms development across
the higher terrain of Colorado and New Mexico and there is a hint
of a weak disturbance moving across the southern Rockies. As this
wave approaches tonight, the modest lift in conjunction with the
moist upslope flow may produce a few more showers. Additionally,
the HRRR suggests a t-storm complex may develop around the western
Okla. Panhandle this evening and slowly propagate to the south-
southeast tonight, not making it into our northern counties until
well after midnight. Deep moisture continues to reside across the
region, and if the dying complex does make it into our area,
moderate rainfall rates could lead to some localized excess runoff
given the saturated soils, but intensity and duration of rainfall
is not expected to be sufficient for any flooding concerns.
Then, the upper-level ridge will slowly migrate east into west-
central Texas Tuesday into Wednesday, and that will tend to shunt
the best rain chances off to our north. Although daily development
in nrn NM and the western Panhandles will have an outside chance
of making into our nrn row of counties each evening into the
overnight hours.
Thursday into Friday, a wave moving out of the Canadian Prairies
into the upper midwest will send a front southward through the
plains. Episodic MCS development and propagation along the
boundary should help drive the front south, and then another
shortwave digging deeper into the central plains over the weekend
should enable the front to pass into/through our forecast area.
The front and northwest flow aloft could set up a favorable
pattern for a period of solid rain chances across the area for the
weekend into early next week. Prior to this, we will see warming
through mid week, with temperatures expected to be back slightly
above average Thursday into Friday, before we begin to cool back
on the weekend.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
07
Area Forecast Discussion
National Weather Service Norman OK
950 PM CDT Tue Aug 8 2017
.DISCUSSION...
There remains a low chance for showers and thunderstorms to move
into northwest Oklahoma before sunrise Wednesday although NAM and
HRRR solutions differ on how far east into Oklahoma any
rain/storms would reach. No changes will be made for the overnight
period at the moment.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 68 86 70 91 / 10 20 10 20
Hobart OK 69 89 71 95 / 10 20 20 20
Wichita Falls TX 70 91 72 95 / 10 0 0 10
Gage OK 66 84 67 91 / 40 30 40 30
Ponca City OK 66 84 69 89 / 10 40 40 40
Durant OK 69 89 71 93 / 10 0 0 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
09/26
Area Forecast Discussion
National Weather Service Pueblo CO
730 PM MDT Tue Aug 8 2017
.UPDATE...
Issued at 728 PM MDT Tue Aug 8 2017
Updated for current pcpn trends and for the cancellation of the
Severe Thunderstorm Watch.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 248 PM MDT Tue Aug 8 2017
...Another Round of Storms...
Shortwave firing convection over the mountains this afternoon headed
this way. Operational hi res model runs are favoring the mountains
and divides for convection this evening, with a little less activity
along the lower Arkansas River Valley. However, the experimental
HRRR does have convection over the valley. At this point, tending
to favor the operational runs with less activity over the lower
Arkansas valley than to the north, south and west as stability may
again be an issue. Temperatures are still running well below
average through the valley which will help to deter convection.
However, I never say never. If the right outflow boundary moves
through, could break through the stable layer and initiate some
strong convection as ample moisture remains and shear values are up
today. Speaking of which, storms this afternoon and evening will
have greater severe potential than in previous days. 0-6KM bulk
shear values are hitting about 40 knots. This is more than enough
for organized storm rotation. The Storm Prediction Center currently
has the eastern mountains and plains under either a marginal or
slight risk of severe the afternoon/evening. A few storms could
organize enough to produce some quarter size hail and 60 mph winds.
Otherwise, threats this evening will include heavy rain, flash
flooding, 50 mph winds, local small hail and lightning. Little
change for Wednesday.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 248 PM MDT Tue Aug 8 2017
An upper level ridge is forecast to be centered to the south of CO,
mainly over NM and TX, Wed night through Sun. Ocnl disturbances
will move thru the west to northwest flow aloft over CO and there
will still be plenty of moisture. As a result there will continue
to be daily chances for showers and thunderstorms, being most
numerous over and near the higher terrain in the late morning hours
through the evening, and spreading acrs the southeast plains in the
late afternoon and nighttime hours.
Heavy rain will continue to be a concern each day. Therefore flash
flooding continues to be a main concern as the ground becomes
saturated from repeated showers and storms. Area burn scars and
urban locations will be most susceptible to flooding.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 248 PM MDT Tue Aug 8 2017
An upper level disturbance and ample monsoon moisture will produce
another round of showers and storms across the area through this
evening. Thunderstorms are firing over the mountains in response to
an advancing shortwave. This development will continue through the
evening, spreading eastward across the plains. MVFR to LIFR GIGS and
VSBYS can be expected in areas of precipitation. Thunderstorm
threats will include heavy rain, gusty winds up to 50 mph, local
small hail an lightning. A few storms over the eastern mountains
and plains could be severe, producing quarter size hail and 60 mph
winds. The KCOS, KPUB and KALS terminals will all be subject to the
conditions described above. Much the same forecast for Wednesday.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...28
SHORT TERM...LW
LONG TERM...28
AVIATION...LW
Area Forecast Discussion
National Weather Service Blacksburg VA
928 PM EDT Tue Aug 8 2017
.SYNOPSIS...
Weak high pressure will build in from the northwest overnight
bringing drier and somewhat cooler air into Wednesday. A weak
warm front will lift north toward the region Thursday into
Friday before dissipating. Another cold front should approach
from the west over the weekend preceded by additional rounds of
showers and storms.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 920 PM EDT Tuesday...
Analysis now showing a bit of low level convergence along the
Blue Ridge where have seen a ribbon of cumulus persist just
north of an axis of jet driven mid/high clouds across the south.
However latest RNK evening sounding showing quite a bit of dry
air aloft, as well as beneath a mid level layer of trapped
moisture within a subsidence inversion. Latest HRRR does show an
isolated shower or two mainly southern Blue Ridge so will leave
in a mention over the next few hours despite relative dryness.
Otherwise mainly clear west to partly cloudy elsewhere before
perhaps seeing a little more in the way of low clouds develop
across the mountains under weak easterly flow. Expect cooling
to near saturation in spots, pending expanse of clear skies, to
also promote at least patchy fog in the valleys and where
heavier rain occurred last night. Should be another rather
comfortable night for early August under less humidity, with
lows 50s west to mid 60s east.
Previous update as of 635 PM EDT Tuesday...
Sent earlier update to lower pops across the southwest given
coverage mainly to the south and short term solutions indicating
only isolated showers at best into this evening. However with
latest analysis showing lack of instability across the southwest
and lower dewpoints now having advected into the NC Mountains,
have cut back pops even further. Cant totally rule out a shower
or two developing along the southern Blue Ridge as the flow
turns more easterly after dark but looks iffy given continued
drying aloft per vapor loop. Thus no more than 20 pop at best
southwest for now. Otherwise tweaked clouds a bit for more
cumulus along the eastern slopes and lowered dewpoints based on
current obs.
Previous discussion as of 250 PM EDT Tuesday...
Latest mesoanalysis showing drier air pushing in from the northwest
as dewpoints drop into the 50s across the northwest CWA and as far
south as the NC mountains, with even some upper 40s into the
Alleghany. Meanwhile dewpoints in the upper 60s to lower 70s still
reside over southside VA into the NC piedmont and foothills.
Aside from a few showers form south of Yanceyville, NC to Scottsburg,
VA our forecast area is dry.
Shortwave energy around the trough axis will still limit how far
southeast the front pushes and in concert the drier air moving
south. The axis of the vort moves from eastern KY into southern VA
through Wednesday. Models in decent agreement in there cloud field
and precip forecast keeping shower chance slight to none into
Wednesday. As the flow around the high turns southeast there could
be upslope showers across the NC mountains Wednesday.
Additionally, late tonight after we have had rain with a
cooler/drier airmass moving overhead, fog should form, especially
along rivers/lakes, and potentially in the mountains with increasing
se flow late. At the moment keeping patchy fog in the forecast, but
may have to see how widespread fog becomes, but would not be
surprised to see dense fog in the New River and Greenbrier Valleys
around dawn Wednesday, and potentiall other mountain locations into
the foothills.
Lows should range form the 50s in the mountains to lower to mid 60s
foothills/piedmont.
Thinking should see stratocu/cu form in the heating of the day
Wednesday so mostly to partly sunny with temperatures still below
normal in the 70s mountains, to lower to mid 80s
foothills/piedmont/Roanoke.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 200 PM EDT Tuesday...
High pressure of the southern New England coast will create the
potential for easterly flow upslope across the southwestern sections
of the area. However, this influence will also wane through the
night as the flow veers more southerly in advance of the next
approaching disturbance across the mid-Mississippi Valley region.
For pops leaned towards the drier GFS solution over the wetter SREF
or NAM. Low temperatures Wednesday night will range from the mid 50s
in the northwest mountains to the mid 60s in the piedmont.
On Thursday as a shortwave approaches from the west. Southerly flow
will increase across western portions of the forecast area, while
the east remains in more of an easterly to southeasterly flow. The
best chance of showers and thunderstorms will be across the western
half of the region. High temperatures on Thursday will vary from
around 70 degrees in the mountains to the mid 80s in the piedmont.
Showers and thunderstorms will increase in coverage Thursday night
with the approach of the upper trough drawing closer. Low
temperatures Thursday night will generally be from around 60
degrees in the west to the mid 60s in the east.
The combination of an approaching frontal boundary, upper shortwave
trough and solar heating will generate scattered showers and
thunderstorms Friday. High temperatures will average below normal
with readings from the the lower 70s in the mountains to the lower
80s in the piedmont.
Showers will taper off Friday evening into Friday night with the
loss of solar heating. Low temperatures will remain above normal
from near 60 in the west to about 70 in the east.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 200 PM EDT Tuesday...
Broad mean trough stays situated from the Great Lakes into the Gulf
Coast states, as a solid ridge remains off the East Coast. The next
upstream frontal boundary slowly edges into the Ohio Valley by
Saturday, reaching the central Appalachians by Monday and pushing to
our southeast Tuesday. Drier air will push south into our region
Tuesday night into Wednesday.
Most of the convection will be diurnal in nature with the greatest
potential as the front moves late in the weekend into Monday. This
far out will see how the pattern sets up in terms of rainfall
amounts and flooding threats.
Temperatures will stay near normal given cloud cover most of the
time, and higher moisture content in the atmosphere.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
As of 655 PM EDT Tuesday...
Expecting ongoing widespread VFR to prevail into this evening
with perhaps periods of broken cumulus around 5K feet over the
next few hours across the mountains. Main concern then overnight
with possible fog/stratus formation despite drying aloft and
lowering of dewpoints under mainly clear skies. Also with the
flow turning light easterly, could see added strato-cumulus bank
up along the Blue Ridge by daybreak as seen in BUFKIT model
solutions. Appears this likely overdone but could limit fog
development late so keeping KLWB/KBCB IFR with possible LIFR
mainly at KLWB given marginal fog stability values off models.
Quite a bit more uncertainty at KBLF with a more southeast
trajectory which should limit stratus with perhaps more of a
short period of MVFR in fog late. Some fog also possible at
KDAN/KLYH if can avoid early strato-cu with possible MVFR vsbys
and IFR late if skies stay clear espcly around KLYH.
Should see any fog/low clouds fade by 14z/10am Wednesday if not
sooner given dry air and light easterly mixing at 5-10 kts.
This should evolve to widespread VFR by afternoon under scattered
to broken cumulus at times.
Extended Aviation Discussion...
The front to the south will remain to the south Wednesday night
before starting to return north Thursday. This will bring
showers and thunderstorms back to the forecast, especially
across southern/western TAF locations mainly Thursday
afternoon. As a result MVFR ceilings and visibilities will
likely return Thursday at KDAN and KBLF and perhaps across the
region Friday. Some improvement possible Saturday under weak
high pressure but still enough convective potential for
localized MVFR conditions Saturday afternoon. Slightly better
chances of showers and storms look to occur by Sunday afternoon
in advance of the next cold front. This likely to spell at least
periods of sub-VFR pending the degree of convective coverage
ahead of the front by then. Otherwise late night/early morning
fog and low clouds also likely each night.
&&
.EQUIPMENT...
As of 200 PM EDT Friday Aug 4...
KFCX doppler radar will be down for the rest of the month due
to a failing bull gear. The radar will only be made operational
for brief periods if an imminent significant widespread severe
weather and/or hydrologic event occurs. Operating the system for
any amount of time until the bull gear is replaced risks a
catastrophic failure that would further extend system downtime.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/WP
SHORT TERM...KK
LONG TERM...KK
AVIATION...JH/WP
EQUIPMENT...WERT