Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/21/19
Area Forecast Discussion
National Weather Service Aberdeen SD
1032 PM CDT Fri Sep 20 2019
.UPDATE...
Issued at 1029 PM CDT Fri Sep 20 2019
Convection is expected to continue to expand into parts of north
central South Dakota, as such increased the severe thunderstorm watch
to cover Corson/Dewey with warned storms just upstream.
&&
.SHORT TERM...(This Evening through Saturday Night)
Issued at 245 PM CDT Fri Sep 20 2019
Main challenge through the short range centers around tonight. Sfc
front/dry line will continue to move only very slowly through the
afternoon, but should pick up forward momentum by mid evening as
mid level trof starts lifting northeast out of the Rockies, and
into the Northern Plains. A few CAMS still show isolated
convection forming out ahead of the front through early evening,
so will keep slight chc pops going across the region for the late
afternoon/early evening. That said, the latest HRRR runs have
backed off on pre-frontal convection to some degree. More
widespread convection appears possible overnight as front
traverses the forecast area. An unstable to very unstable airmass
across the area would support severe storms, however, deep layer
bulk shear will be lacking, and suggests cells could favor pulse
severe. Large cape profiles would support large hail potential
with early evening activity. The main threat from the later
activity will probably be strong wind as mid level winds from
approaching trof overspread the CWA, and force any cells into line
segments. Heavy rain remains a threat given way above normal
PWATs. With only isolated activity anticipated early, and
progressive storms expected later in the evening, will hold off on
any hydro headlines at this time.
Behind the front, conditions will turn cooler and less humid for
Saturday/Saturday night. Lingering showers are possible Saturday in
the north and east. Saturday night should be tranquil and cool. Did
beef up winds from blended guidance given the deep mixing with
afternoon heating. Also boosted temps a touch based on deep mixing
of a still warm airmass.
.LONG TERM...(Sunday through Friday)
Issued at 245 PM CDT Fri Sep 20 2019
Looks like another brief warmup in store for Monday as upper level
ridging moves across the region. MOS guidance was warmer than NBM,
so used a CONSMOS blend for Monday`s highs to get readings a couple
degrees higher. Also used a CONSMOS blend for low temps Wednesday
night as a surface high moves across the area, which was better at
capturing the cooler temp potential compared to NBM. Winds on
Wednesday were increased a bit towards CONSMOS values as both the
GFS and EC agree fairly well in there being breezy/windy conditions
within a tight pressure gradient.
Otherwise, conditions look mainly dry to start out the period on
Sunday. Shortwave energy looks to cross the region mid-week,
bringing a chance of precip. Potential for a stronger system by the
end of next week, but still plenty of time for models to sort things
out. As for temperatures, will see a cooldown mid-week as a cold
front will bring in cooler temperatures. Looking at 60s for highs
for the latter half of next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 544 PM CDT Fri Sep 20 2019
We should have VFR conditions for the most part. Tracking weak
storms near KMBG (and kind of by KABR) through the afternoon,
before another round of storms may come up from the southwest and
impact KPIR. After that, there is some uncertainty but storms will
continue east and possibly impact KABR/KATY. Winds go from
southerly to westerly behind the front for drier conditions for
the most part Saturday.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Connelly
SHORT TERM...TDK
LONG TERM...TMT
AVIATION...Connelly
Area Forecast Discussion
National Weather Service La Crosse WI
1047 PM CDT Fri Sep 20 2019
.SHORT TERM...(This evening through Saturday)
Issued at 312 PM CDT Fri Sep 20 2019
At 3 PM, skies were mostly to partly sunny across northeast Iowa,
and mostly cloudy across the Upper Mississippi River Valley.
Temperatures ranged from the mid-70s to mid-80s.
For late tonight and Saturday morning, the remnants of Imelda will
move northeast through the area. This system will bring with it a
band of showers and storms. With preciptable water values running
close to 2 inches and warm cloud layer depths over 4 km, these
showers and storms will be very efficient rain producers.
Fortunately, it looks like these storms will be rather
progressive, so this will limit the flooding threat.
.LONG TERM...(Saturday night through Friday)
Issued at 312 PM CDT Fri Sep 20 2019
On Saturday night, a cold front will move southeast through the
area. This front will move the fastest north of Interstate 90 and
much slower south of this Interstate. Clouds will likely limit the
instability. While the 0-1 km ML CAPES will be up to 1500 J/kg,
the deep shear will be mainly along and post frontal. Most of the
CAMs are not that impressive with the storms along this front.
However, the latest HRRR would suggest that there may be a few
isolated supercells along this front. The main threat would be
large hail and gusty winds. The main heavy rain threat will be in
southwest Wisconsin and the eastern portion of northeast Iowa
where precipitable water values will be around 2 inches and warm
cloud layer depths will be in the excess of 4 km.
On Sunday, a shortwave will round the base of a longwave trough
moving through the region. It is unclear whether this will bring
additional heavy rain to Grant County in southwest Wisconsin.
From Tuesday night into Wednesday, another longwave trough will
move through the region. Moderate to strong moisture transport
will be found ahead of this system. Precipitable water values will
quickly climb to around 1.6 inches. While 0-1 km ML CAPES will
climb up to 1500 J/kg, the 0-3 and 0-6 km shear looks to be weak,
therefore severe weather is not anticipated at this time.
On Thursday night and Friday, there will be another surge of
moisture into the region as a shortwave trough approaches the
region. Precipitable water values will climb into the 1.6 to 2
inch range. This may result in another bout of heavy rain for the
region.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1046 PM CDT Fri Sep 20 2019
VFR conditions expected at the TAF sites through early Saturday
morning until a push of low level moisture arrives towards
daybreak with an approaching disturbance. This will lead to a
quickly developing cloud deck with low end MVFR to IFR ceilings.
Not anticipating much in the way of convection associated with
this passing feature, but limited instability may support some
showers and perhaps a rumble of thunder or two through ~14Z. Due
to expected limited coverage, have only gone with VCSH in the
TAFs. IFR cigs then expected through early afternoon when daytime
heating should initiate a slight rise to MVFR for the remainder of
the period. There is a small chance for additional showers and
storms in the afternoon, but potential activity looks pretty
limited/unorganized due to weak forcing and some capping aloft.
Have therefore stuck with just VCSH. A somewhat better chance for
storms will come after 00Z Sunday as a cold front drops into the
area, so have introduced VCTS Saturday evening.
Southeast winds will gradually increase through early Saturday
morning as the pressure gradient strengthens overhead, becoming
more southerly by daybreak. Winds will turn gusty by mid-morning,
especially at RST where gusts approaching 30 knots are possible
through the afternoon. Gusts will diminish with sunset, but winds
will remain breezy as they shift to the southwest ahead of the
front.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Boyne
LONG TERM...Boyne
AVIATION...Kurz
Area Forecast Discussion...Updated
National Weather Service Billings MT
849 PM MDT Fri Sep 20 2019
.UPDATE...
Made only minor adjustments for the update. Central part of
forecast area was in a dry slot this evening, with a N-S line of
thunderstorms over SE MT, and rain to the W of KBIL. 500 mb
trough was over W MT/E ID/NW WY at 02Z while 700 mb low was
further E with drier air riding N into the area from WY. 700 low
will shift into W ND overnight...allowing rain to overspread the
entire area. Noted RAP soundings had MUCAPES just below 1000 j/kg
for much of the night over SE MT and Sheridan County. Effective
Bulk Shear was high as well, but winds were backing with height
due to cold advection around the system. 12Z HREF did have some
helicity tracks over SE MT but these looked overdone thus far. So,
kept thunder in the forecast in the SE and in the Sheridan
Foothills, but did not have any strong storms mentioned. Elsewhere
had just rain, with snow in the mountains. RAP soundings showed
freezing levels dropping to just under 8000 ft AGL tonight. 700 mb
gets pretty cold, with -3 degree C air moving into the W. While
best dynamics will be over E MT with the jet, upslope N flow and
decent QPF will support warning snow amounts in the Absaroka/Beartooth
mountains. So no changes to WSW or the HWO which also mentions
the heavy rain amounts for the area. Boosted winds up a little
overnight and adjusted PoPs for current trends. Arthur
&&
.SHORT TERM...valid for Sat and Sun...
Upper low is currently sitting just south of Yellowstone park and
is on a slow northeasterly trajectory that should take it over
Sheridan county by midnight and into Carter county by sunrise
tomorrow morning. Heaviest precipitation with this system will be
to the north of this track from Livingston to just south of
Billings to Baker/Ekalaka. Already seeing reports of around an
inch of precipitation from Nye to Red Lodge and as far north as
Columbus this afternoon. Expecting another half inch to inch and a
half along this heavier precipitation band overnight into tomorrow
morning. No big changes to the snow forecast and going Winter
Storm Warning this afternoon, with 10 ot 18 inches of snow
expected above 7500-8000 feet. Temperatures above 7000 feet are
in the 30s at mountain reporting sites and radar shows the
freezing level around 7700 feet at this time.
The storm system will shift to the east tomorrow morning with
gusty northwest winds building in behind it. Gusts over Sheridan
county and across SE Montana could gust over 40 mph at times.
While the heavier steady precipitation will taper off during the
morning, isolated to scattered instability showers under the
upper trough will continue into early evening.
Sunday looks sunny with highs in the 70s. Chambers
.LONG TERM...valid for Mon...Tue...Wed...Thu...Fri...
Split flow over the western CONUS on Monday will mean little
chance of any impact weather with only weak forcing and moisture
available over our region, but we could see a few light showers
over the mountains and foothills. Otherwise, a transition to
faster zonal flow will bring dry conditions for our lower
elevations thru Tuesday. Flow aloft will veer to the NW Tuesday
night and Wednesday. As heights drop at midweek we will see an
increasing chance of light showers in the NW flow. We could also
possibly see our first gap wind highlights of the season at
midweek. Mid level temps will fall enough to bring a risk of more
snow showers for the high elevations.
Information from ensembles analysis provides increasing confidence
of a deep trough developing over the western CONUS toward the
latter end of next week. This pattern change would lead to
cool/wet weather setting up for our region beginning Thursday and
potentially lasting thru the weekend.
Temperatures will begin near or a little above normal Monday thru
Tuesday, then fall below normal thereafter. Significantly cooler
temps are then possible by next weekend. BT
&&
.AVIATION...
Conditions will range from MVFR to LIFR across the area into
Saturday morning in rain and thunderstorms. Expect gusty WNW
surface winds tonight through Saturday as well. Conditions will
improve to VFR across the area by Sat. afternoon. Widespread
mountain obscurations will continue through Sat. morning and
decrease in the afternoon. Arthur
&&
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
-----------------------------------------------------------
BIL 048/064 046/073 049/075 051/075 049/065 046/064 043/059
+6/W 20/U 01/B 10/U 22/W 22/R 44/R
LVM 041/061 040/070 043/070 044/070 042/064 039/060 037/056
96/W 10/U 12/W 10/N 22/W 23/R 45/O
HDN 046/062 043/072 046/075 047/074 046/064 043/064 042/060
88/W 20/U 01/B 00/U 22/W 22/R 34/R
MLS 050/063 045/073 048/076 050/071 046/063 043/063 042/060
88/W 10/U 00/U 00/B 21/B 22/R 33/R
4BQ 046/062 042/071 044/076 047/073 045/063 042/065 041/061
79/W 20/U 01/U 10/U 21/B 21/E 23/R
BHK 048/062 043/071 046/076 048/070 044/061 041/062 040/060
9+/W 20/U 00/U 00/B 21/B 22/R 33/R
SHR 042/060 038/071 042/074 043/073 043/063 039/064 039/061
78/W 30/U 01/B 10/U 22/W 22/R 33/R
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning in effect until noon MDT Saturday FOR
ZONE 67.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Goodland KS
922 PM MDT Fri Sep 20 2019
.UPDATE...
Issued at 922 PM MDT Fri Sep 20 2019
Stronger gusts near 35 to 40 mph are showing up across portions
of the CWA. Going forecast was updated to reflect the increased
wind conditions.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 230 PM MDT Fri Sep 20 2019
Overview: Southerly flow aloft will transition to southwesterly
flow aloft over the Central Plains in this period -- as an upper
level low invof Yellowstone (today) lifts northeast through the
Dakotas (Saturday) into Manitoba/Ontario (Saturday night).
Through Tonight: Breezy southerly flow on the eastern periphery
of a lee cyclone in northeast Colorado will persist through this
evening, gradually veering to the SSW-SW-WSW overnight as the
cyclone weakens and progresses into central Nebraska. Simulated
reflectivity forecasts via the HRRR suggest that isolated
convection will develop between Lamar-Tribune around 20-21Z
(presumably in association with low-level convergence on the
eastern periphery of the lee cyclone) -- with activity progressing
northeast toward Colby/Oakley through ~00Z. Visible satellite
imagery and radar data show agitated Cu and the onset of faint
reflectivity echoes ENE of Lamar at 20Z, lending support to the
aforementioned HRRR forecast. Though mid-level lapse rates are
relatively weak (6.5-7.0 C/km), instability is marginal (500-1000
J/kg MLCAPE), and forcing is largely confined to low- level
convergence, effective deep layer shear on the order of 30-40
knots suggest a conditional potential for organized updrafts /low-
end isold severe potential/ may exist between 21-01Z.
Sat-Sat night: Shortwave energy digging southward through Nevada
this afternoon will round the base of a broad trough over the
Intermountain West on Saturday, ejecting ENE across the Rockies
Saturday night. A lee cyclone will develop in advance of this
feature in southeast Colorado on Sat, progressing eastward into
Kansas Saturday night. With the aforementioned cyclone progged to
track eastward invof Hwy 50 -- and an attendant thermal/moisture
boundary extending northeast from Ulysses-Garden City-LaCrosse-
Russell, surface based convection is generally anticipated to
remain south and east of the GLD county warning area during the
afternoon, though elevated convection will be possible in advance
of the progressive shortwave -- on the N-NNW periphery of the
aforementioned cyclone Sat eve/night, primarily in northwest KS.
.LONG TERM...(Sunday through Saturday)
Issued at 211 PM MDT Fri Sep 20 2019
The extended forecast begins with an upper level trough
progressing eastward into the region and a surface low over
western and central Kansas. We may see a few lingering showers in
our eastern counties early Sunday morning as the system moves out
of the region, but the better chance for rain will be in the prior
time period.
Monday, weak ridging over the Central High Plains will allow our
temperatures to warm to near normal with dry conditions across the
region for the daytime hours. An upper level low over western
Nevada will push south into southern California and western
Arizona. Going into the evening and overnight hours, a few
isolated showers or thunderstorms will be possible as a shortwave
trough moves through the region. High temperatures will be in the
80s and overnight lows going into Tuesday morning will range from
the low 50s to low 60s.
Tuesday, the flow will become northwesterly over the Tri-State
region. Both the GFS and the ECMWF show pretty good agreement on
the upper low becoming cut off Tuesday and remaining over southern
California and Arizona through Wednesday evening.
The low will begin to track to the northeast through the day
Thursday. Was okay with a few isolated storms in the forecast in
the evening as the system begins to move into the forecast area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 518 PM MDT Fri Sep 20 2019
The passage of a frontal boundary thru the forecast period...is
going to allow for VFR/dry conditions with a mix of scattered mid
clouds and SKC.
Winds for KGLD...SE 25-35kts thru 04z Saturday...then SW
10-20kts. By 07z...NW 10-15kts becoming N by 12z. A shift to the
NE around 10kts will occur from 18z onward.
Winds for KMCK...SE 15-30kts thru 06z Saturday...then SW
10-20kts. By 10z...WNW 10-15kts becoming NNW by 15z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JN
SHORT TERM...VINCENT
LONG TERM...AW
AVIATION...JN
Area Forecast Discussion
National Weather Service Key West FL
919 PM EDT Fri Sep 20 2019
.DISCUSSION...In the middle and upper levels(700-200 mb), latest
available satellite imagery overlaid with model streamline
analysis as of 800 pm, depicts a sharp but narrow middle and upper
trough axis that is positioned from the NW Atlantic well east of
Atlantic Canada south southwest thru Florida and the Keys down to
a slowly pinching TUTT cell over the Western Caribbean Sea. West
of that the center of a deep and warm anticyclone is positioned
across Northeastern Old Mexico, with the eastern periphery of this
expansive ridging reaching the Eastern Gulf of Mexico and the
Yucatan Peninsula. Well to the east of the sharp trough, the
center of another deep and warm synoptic scale anticyclone was
positioned near 30N 50W with an attendant ridge axis extending
southwest to just west thru north of Hurricane Jerry. At 800 pm,
the center of Hurricane Jerry was located near 19.9N 62.5W, which
is about 125 miles NNE of Anguilla in the Northern Leeward
Islands.
At the surface and in the lower to middle levels(Surface to 700
mb). latest available marine and land surface observations and
analysis as of 800 pm, detail near 1030 mb surface ridging
centered from Cape Hatteras to Western South Carolina. 4-panel
CIRA LPW layered precipitable water delineates the leading edge
of deep moisture with columnar PWAT averaging between 2,00 and
2.25 inches approaching the extreme SE Florida Peninsula as well
as the Eastern Florida Straits and just shy of the Upper Florida
Keys attm. Well upstream of that Keys exists a strong tropical
wave axis at the longitude of the Windward Passage. The
combination of these features is resulting in an unusually tight
MSLP gradient, resulting in strong breezes. As such, the 00Z
evening sounding at KEYW illustrated
.CURRENTLY...As of 800 pm, skies were partly to mostly cloudy
across the islands and surrounding waters. Radar detects scattered
showers and a few thunderstorms which have began to infiltrate
the area from the east in the last few hours. Individual shower
activity continues to move at an average speed of about 25 knots,
but the stronger cells are moving between 30 and 35 knots, which
has required continual issuances (late this afternoon and thus far
this evening) of marine weather statements and a few special
marine warnings in which some wind gusts over 40 knots appear
likely. Temperatures across the islands outside of the fast moving
shower activity are in the lower 80s, but dropping into the upper
70s in some showers. C-man stations along the Florida Reef as
well as at Smith Shoal Light and in Florida Bay are averaging east
at 20 to 25 knots with occasional gusts over 30 knots. Occasional
gusts between 30 and 35 knots are more likely occurring across
the deeper Florida Straits waters.
.SHORT TERM...Overnight and Saturday, the strong 1025-1030 mb
surface ridging centered over Eastern North Carolina will remain
in place overnight thru the day on Saturday. Upstream of the Keys
as mentioned above, moisture will deepen in the column from 850 to
500 mb later tonight and during the day Saturday. Also,
intermediate runs continue with model time height analysis
exhibiting decent 850-700 mb maxima in the omega fields. Given
this in concert with weak cyclonic curvature, very strong
surface/low level confluence always takes shape, resulting in
coverage of numerous showers. This will be the case for at least
the next 36 hours. So will be increasing the 12 hour rain chance
(pops) for tomorrow, as HRRR and other meso- scale models
increasing coverages of these fast moving showers.
For the rest of tonight, the ongoing, likely, 60 percent pops
looks good for the overnight period (thru 6 am), but as we
approach dawn and the column continues to moisten with PWAT
exceeding 2.00+ inches, will increase rain chances from high
chance, 50%, to likely, 70% for the day on Saturday (6 am to 6pm).
Also, given current observations, will just increase winds over
the islands to between 20 and 25 mph for the overnight period.
And although these will be the sustained winds over the islands,
it is important to remember that this will be outside of any and
all showers and isolated storms. Occasional gusts between 35 to
45 mph will be likely in some of fast moving showers and isolated
storms. Issuances of significant weather advisories for portions
of the affected Keys Island Chain islands will occur when
an available weather station(s) sensor reports any wind gusts
that exceed 45 mph. No other changes on this cycle.
&&
.MARINE...Overnight and Saturday, Small Craft Advisory (SCA )conditions
on all waters with very hazardous conditions expected. Winds will
increase this evening to around 25 knots with occasional gusts
exceeding 30 knots across all waters in the marine district this
evening, except some portions of the waters may increase to
between 25 to 30 knots with occasional gusts exceeding 35 knots.
These conditions will continue during Saturday. In some isolated
heavy showers and thunderstorms, wind gusts in excess of 40 to 45
knots will be possible. If radar detects these conditions, then a
special marine warning will be issued.
&&
.AVIATION...Strong east breezes with gusts commonly near 25 knots will
continue through Saturday.
Increasing coverage and intensity of fast-moving showers and
eventually thunderstorms will be the other concern for the next 24
hours. At some time on Saturday, both island terminals are likely
to see significant round(s) of thunderstorms accompanied by 1-3SM
visibility in heavy rain, along with BKN cigs in the 020-030
range. Storms should also come with brief convective wind gusts
near 35 knots.
However, guidance is at odds with the most likely time on Saturday
for thunderstorms. Some guidance focuses on Saturday morning, other
guidance focuses on the afternoon, and others nearly all day. The
TAFs currently reflect VCTS for weather starting at midnight
tonight, but will have to wait for more timing certainty before
adding TEMPO group(s) for thunder. Pilots should plan their Saturday
flight operations for the possibility of active convective weather
and the certainty of gusty winds.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory until 5 AM EDT Saturday for GMZ031>035-
042>044-052>055-072>075.
&&
$$
Public/Marine...Futterman
Aviation/Nowcasts/Statements/Warnings....Haner
Upper Air/Data Collection/Public Service......NB
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Area Forecast Discussion
National Weather Service Louisville KY
706 PM EDT Fri Sep 20 2019
...Updated Aviation Discussion...
.Short Term...(This evening through Saturday)
Updated at 323 PM EDT Fri Sep 20 2019
Convection from earlier this morning into the afternoon has
diminished for the most part. A few very light showers linger in our
Bluegrass region, but otherwise we are dry. The next focus for any
shower activity will be across southern Indiana toward sunset. The
HRRR has been consistent in showing some isolated development by 21-
22z in that area. The latest mesoanalysis data shows around 1500-
2000 J/KG of SB CAPE up in that area, however any convection will
likely be mitigated by a mid level inversion (~15000 Feet) evident
on forecast and AMDAR soundings. As a result, have only included
showers in the forecast and will leave thunder potential out. Some
of these showers could spill into the Louisville metro after sunset
so will mention a 20% pop along and north of I-64.
Any shower activity should diminish before Midnight, with dry
conditions persisting thereafter. Temps should drop back into the
60s for lows given modest radiational cooling conditions under
mostly clear skies.
Dry conditions will continue again tomorrow due to the upper ridge
and a notable subsidence inversion evident on forecast soundings. A
steady SW wind combined with 850mb temps around 16C should yield
highs in the upper 80s and low 90s. Decided to lean on high side of
guidance due to drought conditions and recent overachieving of
temps.
.Long Term...(Saturday night through Friday)
Updated at 250 PM EDT Fri Sep 20 2019
The persistent warm, dry ridge of high pressure aloft from the
southeastern U.S. into the lower OH Valley at the start of the
extended period will get shunted southward temporarily as a strong
shortwave trough moves across the upper MS Valley and Great Lakes
states on Sunday and Monday. This system will drive a cold front
southeast across the lower OH Valley and our area Sunday night and
Monday. Widespread showers and t-storms associated with the front
will occur well to our north and west on Sunday. However, as rain
spreads southeast toward the upper ridge, expect a weakening trend
in coverage and amounts over our area, where rain is much needed.
Showers will become more scattered in nature. Based on current model
solutions, expect rainfall amounts to vary from roughly around 0.25
inch in parts of southern IN to maybe around 0.1 inch south of the
OH River to only a couple/few hundredths of an inch in south-central
KY. Definitely no drought buster.
Surface high pressure will build into our area Monday night and
Tuesday with high temperatures closer to normal. Then, another broad
shortwave trough is forecast to move across the northern U.S. states
during the mid part of next week. This should drag another front
southeast across the OH Valley roughly Wednesday night or Thursday,
with only isolated to perhaps scattered showers possible in parts of
our area. Again, at this time, it looks like little or no help with
the drought.
However, this frontal boundary should not make it too far south as
the upper ridge begins to expand northward again. By the end of next
week, all models show this pesky ridge back in control over the
lower OH Valley and points southward, with a return to very warm to
potentially hot temperatures next weekend into the start of the
following week.
&&
.Aviation...(00Z TAF Issuance)
Updated at 705 PM EDT Fri Sep 20 2019
VFR conditions are expected this evening and during the overnight
hours. Winds will generally be light out of the south to southwest.
For Saturday, look for VFR conditions across the region with a
diurnal Cu deck around 5-6 Kft AGL. Winds will be out of the
southwest at 8-10kts.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Short Term...BJS/CSS
Long Term....TWF
Aviation.....MJ
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
642 PM CDT Fri Sep 20 2019
.SHORT TERM... (Through Late Saturday Night)
Issued at 253 PM CDT Fri Sep 20 2019
No changes to the Flash Flood Watch.
Moisture continues to surge northward into the region, evident in
TSRA coverage over southern portions of the CWA. Storms should
diminish with sunset, however, expect storms to linger a little
longer than over the past couple of days.
The focus of precip should shift to western, then northern,
portions of the CWA as the LLJ increases. That said, with the vort
max over southern MO into AR lifting into the region, going
forecast may not have high enough PoPs far enough southeast.
Models are also suggesting a band of showers lifting eastward
through the central portions of the CWA around and just after
sunrise. Some of the later cycles of the RAP have shifted this a
little further north. As such, confidence remains on the lower end
for timing and placement.
Still expect precip to gradually diminish through the morning
hours. After a lull in activity through much of the afternoon,
expect precip coverage to increase across northern portions of the
CWA during the late afternoon and persist through the overnight
hours.
Tilly
.LONG TERM... (Sunday through Next Friday)
Issued at 253 PM CDT Fri Sep 20 2019
Main focus continues early in the period. A confluent upper trof
approaches the region on Sun with the surface cold front reaching
northern portions of the CWA mid to late Sun morning. Moisture
advection ahead of this front continues with PWs of 2+ inches.
With the LLJ parallel to the front, training storms will be
possible. These factors in addition to high freezing level and
the high PWs, a threat of flash flooding exists for mainly the
northern third or so of the CWA. However, will keep the watch as
is due to continued uncertainty. With the available CAPE and deep
layer shear ahead of the front on Sun, will need to continue to
monitor a severe threat.
The cold front is expected to push south through the area Sun
night with rain coming to an end. After a dry Mon and most of
Tues, the chance for rain increases again mid to late week. With
differences among model solns, have kept PoPs low for now.
Tilly
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 632 PM CDT Fri Sep 20 2019
Showers and storms will continue to diminish over the next few
hours and we should have a quiet latter half of the evening.
Precip chances will then return after midnight in central MO,
pushing toward NE MO and west-central IL prior to sunrise. The
highest precip chances will linger in these areas through much of
the day tomorrow, though it does look like there may be a bit of a
lull in storm activity in the early afternoon. Cigs are expected
to dip into MVFR with these morning showers and storms, gradually
increasing by the late morning.
For east-central MO, SE MO, and southern IL, precip chances will
be a bit lower, though activity is expected to be greatest in the
morning before diminishing somewhat in the afternoon. That said,
isolated storms are likely tomorrow afternoon, but confidence in
these storms impacting a terminal is low. Obviously conditions
will deteriorate for areas impacted by storms.
BSH
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 72 85 73 84 / 60 40 20 80
Quincy 71 79 68 73 / 60 70 90 80
Columbia 69 80 69 77 / 50 50 50 80
Jefferson City 69 82 70 79 / 50 50 40 80
Salem 67 83 70 86 / 60 10 5 60
Farmington 66 82 68 85 / 30 20 5 60
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Flash Flood Watch from Saturday evening through late Sunday
night for Audrain MO-Boone MO-Callaway MO-Knox MO-Lewis MO-
Marion MO-Monroe MO-Montgomery MO-Pike MO-Ralls MO-Shelby
MO.
IL...Flash Flood Watch from Saturday evening through late Sunday
night for Adams IL-Brown IL-Pike IL.
&&
$$
WFO LSX