Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/06/19
Area Forecast Discussion
National Weather Service Hastings NE
629 PM CDT Sat Oct 5 2019
.SHORT TERM...(This evening through Sunday night)
Issued at 310 PM CDT Sat Oct 5 2019
Aloft: RAP dynamic tropopause analyses and WV imagery showed a
fairly potent shrtwv trof over the GtPlns. Low-amplitude WNW flow
was over the Wrn USA with another shrtwv trof over the Pac NW. The
flow over NEB/KS will become W tonight and then WSW after 12Z/Sun
as the Pac NW trof crosses the Nrn Rckys and approaches the rgn.
This trof will then move thru tomorrow...shifting winds to NW
after 18Z.
Surface: 1002 mb low pres was over MN. The cool front that moved
thru early this AM extended S from the low thru IA-MO to the TX
Panhandle. High pres over the Pac NW was nosing into NEB/KS. This
high will strengthen to 1034 mb tonight...with a piece of this
high breaking off and emerging onto the Cntrl Plns tomorrow.
Rest of this afternoon: Sunny and breezy. NW winds 15-25 with
occasional G35. Winds will be gradually diminishing.
Peak gusts include 51 mph at ODX...50 mph near Sherman Reservoir.
LSR`s have been sent.
Tonight: Mostly clear in the eve...but becoming mostly cldy after
midnight as clds increase ahead of the incoming trof.
Frost N and W of the Tri-Cities was removed from the fcst. Clds
should keep temps from dropping into the mid 30s and temp-dwpt
spread will be 6-9F.
Sun: Cldy in the AM. Gradually dcrsg clds from the N after
midday. N-cntrl KS will remain mostly cldy thru the day. There
could be some very light rain or sprinkles W of Hwy 281 in the
afternoon.
Highs 61-65F.
Sun night: Clear and cold. Almost ideal radiating conds. Went
with MOS for lows. May need a Frost Advisory for much of the CWA
if I`m reading the situation right. Freeze Warning psbl
Valley/Greeley counties.
Lows 31-40F.
.LONG TERM...(Monday through Saturday)
Issued at 310 PM CDT Sat Oct 5 2019
Aloft: The last 3 runs of global mdls (GFS-FV3/EC/UKMET/CMC) are
tightly clustered thru next Thu...but spread dvlps Thu night into
Fri with the last 3 GFS-FV3 runs on the fcst side of the guidance
envelope. A shrtwv trof will strengthen over AK tonight in
response to upstream amplification related to a storm moving up
the E coast of Russia. This trof will dig/deepen over Wrn Can Mon.
It will then sink into the Pac NW Tue with a sig trof dvlpg over
the Wrn USA Wed...from MT-Srn CA. This trof will cross NEB/KS Thu
with an upr low possibly forming. NW flow in its wake Fri-Sat with
dcrsg amplitude as the low or trof moves into the GtLks. Over
NEB/KS...low- amplitude WNW flow Mon will become WSW Tue...and
then SW Wed until the trof moves thru.
Surface: Srn Plns high pres will head into the Ern USA/Can Mon-
Tue with breezy return flow/WAA Mon-Wed AM as downslope-warmed air
overtakes the rgn. An unseasonably cold air mass will plunge into
the NW USA. A strong cold front will cross NEB/KS Wed followed by
cold high pres Fri-Sat.
Temps: Near normal Mon. A little warmer than normal Tue. Near
normal Wed. Then much cooler than normal Thu-Sat with a warming
trend. The coldest day will be Thu with much of the CWA not
getting out of the 40s!
Our fcst high temps for Thu and Fri may not be cold enough
because of the climo bias from MOS input into the fcst blend. The
consensus of mdl 2m temps suggests our fcst could bust 5-10F too
warm for highs both days. Plan on colder than what the fcst
currently states.
The 00Z EC ensemble mean and 12Z GEFS mean bring the -3C 850 mb
isotherm all the way down into N-cntrl KS by 12Z/Fri. The 06Z GEFS
brings the -6 isotherm down to I-80. That is 2 SD below normal!
Thu will be windy and cold!
Fri AM and Sat AM we are looking at widespread sub-frzg lows...
espcly Fri AM with widespread mid-upr 20s over most of the CWA.
That would end the growing season.
Suggest everyone with gardens quickly harvest anything left.
Rain/Snow: Sct shwrs/tstms Wed night ahead of the front.
Uncertainty really increases. We need to see how the upr trof
evolves and if a low dvlps. Rain could then move in from the NW
with rain changing to snow...probably N and W of the Tri-Cities.
Can`t rule out a little snow elsewhere...but the greatest chance
(and it may not be all the great) of accumulating snow will be N
and W of the Tri-Cities. The best chance for accumulating snow
will be over the Panhandle and Sandhills...N and W of the CWA.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 617 PM CDT Sat Oct 5 2019
Anticipating VFR conditions through the forecast period. Winds
should decrease this evening and be variable overnight as surface
high pressure builds into the area. High clouds will also push in
overnight ahead of a shortwave trough, and these will hang around
until early afternoon.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Ewald
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
1001 PM EDT Sat Oct 5 2019
.SYNOPSIS...
A cold front will continue to approach from the region from the
west tonight, reaching the area Sunday into Sunday night.
Another high will build in behind this front and persist through
mid week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Mid to high clouds have reached the northwest corner of the fa.
They will continue to advance overnight ahead of an approaching
cold front. The scattered showers over Indiana will work into
western locations late.
Southeastern parts of the fa with be affected by an increasing
low level after midnight, which will provide enough lift for
scattered showers and the chance of some thunder.
Lows tonight will range from the upper 50s to the mid 60s.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
Initial s/wv will be out running the frontal boundary Sunday
morning. Induced pcpn in the southeast will move east while a
chance of showers will continue along the front boundary. By the
time the front moves into our eastern/southeast zones during the
afternoon, there may be enough diurnal heating and convergence
for the likelihood of showers, perhaps a rumble of thunder,
there. It will likely temporarily dry out in the northwest
behind the front during the afternoon. Highs will range from
near 70 northwest to the mid/upper 70s southeast.
Another embedded s/wv, mid level energy, is still expected to
dig east into the region Sunday night. Our area, particularly
the southern/eastern locations, will come under the RR quad of
an upper level jet which will provide upper level divergence.
Meanwhile, this will help induce a low level jet/convergence
which will bring low level forcing/ascent near and over the
frontal boundary as it slowly moves southeast. There continues
to be a fairly tight gradient in terms of decent rainfall
amounts, mainly focused along and southeast of I-71. This is
where categorical PoPs will be used with chances decreasing as
one moves towards west central Ohio. There could be a rumble of
thunder early on across the southeast. Lows will range from the
upper 40s northwest to the lower/mid 50s elsewhere.
On Monday, as the mid level s/wv moves east across the region,
upper level energy and low level forcing will rotate east as
well. There will be a decrease in pcpn during the day from west
to west with all locations expected to be dry by Monday evening.
Clouds will hold on in the east, while skies should become
partly cloudy in the west by afternoon. Thus, highs will range
from near 60 in the east to near 65 in the west.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
The long term time frame will be quiet through most of the week
as a large surface high pressure begins to build into the CWA
from the lower Ohio Valley behind the departing frontal system.
The high will slide northeast to the Canadian Maritimes by the
end of the week. The next impacting system approaches the region
from the west Friday into Saturday.
Monday night begins with surface high pressure centered near
Illinois. Model consensus shows the high shifting quickly toward
New England through the day on Tuesday and continuing toward
the northeast into mid week, with surface flow swinging around
from the northeast to the east on Tuesday, then to the southeast
by late Wednesday. While temperatures begin the period below
normal on Tuesday, the quick return flow brings them back to
above normal levels starting on Wednesday into Thursday. Around
this time, an upper level low will be digging southeast from the
northern Rockies, then ejecting eastward into the northern
Plains and upper Midwest by late Friday. Model solutions show
wide differences with this system at 00Z on Saturday, as the GFS
has a 519 dm H5 low placed just north of the arrowhead of MN,
while the Euro has a 541 dm H5 low 400 miles to the southwest
near Sioux Falls, SD. This leads to large differences in frontal
placement and sensible weather, with the GFS quickly pushing a
cold front through the CWA on Friday morning, with the Euro
fropa almost 24 hours later. Used a blend, went with chance PoPs
from late Thursday into Saturday.
Despite timing differences, models show a sharp cutoff of
moisture and clouds behind the front in westerly low level flow.
Have this pushing into the CWA later on Saturday to close out
the extended period.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Surface high pressure will continue to exit to the east
tonight. Conditions will be VFR through 12Z, but high and mid
clouds will be on the increase after 06Z. Models are producing
some light QPF ahead of the advancing cdfnt in an area of low
level convergence and shearing H5 disturbance. Scattered showers
are forecast into the western zones shortly after 12Z. Kept them
VCSH due to the scattered nature.
This line of scattered showers will work through the tafs during
the morning hours, pushing southeast of I-71 around 18Z. This
will bring dry conditions to the TAFS for the afternoon hours.
There are some indications that the low levels could become
saturated around the eastern tafs during the afternoon. This
could bring some MVFR ceilings. Confidence is not high enough
to add them at this time.
After 00Z Monday, a second surge of moisture is forecast to lift
across the tafs. Added some light prevailing showers to the CVG
taf to indicated this.
OUTLOOK...MVFR ceilings and visibilities are possible on Sunday
night into Monday
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Hickman
NEAR TERM...Sites
SHORT TERM...Hickman
LONG TERM...Hogue
AVIATION...Sites
Area Forecast Discussion
National Weather Service Lincoln IL
703 PM CDT Sat Oct 5 2019
.SYNOPSIS...
Issued at 241 PM CDT Sat Oct 5 2019
A cold front shifting across central and southeast Illinois, will
bring scattered showers and isolated thunderstorms, into tonight.
The front will stall near the Ohio River on Sunday, keeping
unsettled weather south of I-70, into Sunday night.
&&
.UPDATE...
Issued at 703 PM CDT Sat Oct 5 2019
Updated the forecast to lower PoPs significantly as the band of
showers/thunder that passed through the area late this afternoon
is now quickly exiting into Indiana. Behind the band, 00z/7pm
radar imagery is showing dry conditions across the remainder of
central Illinois. With a cold front still poised to the west
across Iowa/Missouri, cannot rule out an isolated shower through
the evening...similar to the latest HRRR depiction. Think showers
will become a bit more numerous along/ahead of the front after
midnight, primarily along and east of the I-57 corridor. Have
therefore gone with isolated evening showers across much of the
CWA, with scattered shower wording through the night across the
E/SE. Once the front passes, skies will clear from west to east
overnight. Lows will range from the upper 40s west of the Illinois
River where skies will clear soonest...to the upper 50s south of
I-70 where clouds/showers will persist through the entire night.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 241 PM CDT Sat Oct 5 2019
A band of showers and thunderstorms has steadily been marching
east today and is now entering the far western CWA. This is
occurring in a pre- frontal trof and area of focused 925-850mb
moisture advection. Models are consistent in weakening moisture
advection as the zone of lift shifts east this evening, causing an
overall diminishing trend in shower/storm coverage. As a result
we have likely pops across the west late this afternoon, lowering
to chance pops for shower/isolated thunder this evening
central/east. After the initial zone of lift diminishes, an
isolated shower is possible until the occluded front sweeps west
to east later this evening. Models point to a good clearing trend
behind the front, which is currently noted in visible satellite
imagery across eastern NEB into SW IA. Upper 40s lows expected
west of the IL River due to clear skies, while clouds lingering SE
of I-70 to keep mins in the mid/upper 50s.
While drier air working in behind the front brings a nice Sunday
the central/northern CWA, rain chances linger into Sunday evening
south of I-70. This, as the front stalls south of the Ohio River,
and to several weak mid level impulses lift northeast. So a few
periods of showers and isolated storms possible in the far south
which would be beneficial rain. With neutral air advection behind
the front, seasonable temps to end the weekend.
.LONG TERM...(Monday through Saturday)
ISSUED AT 241 PM CDT Sat Oct 5 2019
Monday through Wednesday...an excellent stretch of fall weather
is on tap. Upper heights rise while flow quickly transitions from
northwest Monday to southwest Wednesday. This while surface high
pressure dominates for dry conditions. We expected temperatures to
warm a couple degrees each day, which would put readings several
degrees above normal Wed/Thu.
On Thursday a deep longwave trof emerging from the Rockies into
the Plains, increases moisture advection ahead of the next strong
cold front. So shower and thunderstorm chances return to the
forecast, and continue into Friday. Still plenty of model spread
on timing the strong cold front, which will end the precip
threat. However there is better consensus that an unseasonably
cold fall airmass will move into the Midwest behind the front.
Temperatures have trended lower for Friday into Saturday. Plenty
of details to work out with respect to clearing and winds, but
widespread lows in the mid to upper 30s now look likely Saturday
morning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 657 PM CDT Sat Oct 5 2019
Band of showers/thunder has passed well east of the terminals
early this evening, with dry conditions noted across much of
central Illinois. Since cold front is still well to the west
across Iowa/Missouri, cannot rule out a stray shower before it
passes. Have therefore included VCSH at all TAF sites. Main
aviation concern is a band of MVFR ceilings currently noted west
of the Illinois River. Based on HRRR RH progs and satellite timing
tools, have lowered ceilings to MVFR at KPIA by 01z...then further
east to KCMI by 05z. Once the cold front passes, the low clouds
will quickly depart and skies will clear from west to east
overnight. Winds will initially be S/SE this evening, then will
veer to the W/NW at KPIA by 04z...and further east at KCMI by 06z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SYNOPSIS...25
SHORT TERM...25
LONG TERM...25
AVIATION...Barnes
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1050 PM EDT Sat Oct 5 2019
.UPDATE...
Issued at 1050 PM EDT SAT OCT 5 2019
The isolated showers and storms have decreased over the last
hour; however, the showers that moved over the Jackson Weather
Office were enough for the ASOS to measure 0.02 inches of rain.
This halts the streak for days without measureable precipitation
for the Jackson Julian Carroll Airport at 37 days. There are more
showers and storms upstream in Tennessee that are moving northeast
into south-central Kentucky. Have updated PoPs to reflect this
trend. Isolated showers may continue through the morning, but the
main bulk is expected to occur with frontal passage tomorrow
afternoon. Also, ingested the latest observations and blended into
the overnight hours. Current temperatures range from the lower
60s to mid 70s across eastern Kentucky. Ran a new ZFP to remove
evening wording. Updates have been sent to the web and to NDFD.
UPDATE Issued at 818 PM EDT SAT OCT 5 2019
A few isolated showers and thunderstorms have developed along an
inverted trough in southeastern Kentucky this evening. The HRRR
shows this activity decreasing through 2Z, so have followed this
thinking with adjustments in PoPs. Did introduce thunder into the
grids during this time as well; therefore, did update the HWO to
reflect this. No other major changes were needed beyond ingesting
and blending the latest observations. Current temperatures are
generally in the lower to upper 70s across eastern Kentucky. As a
cold front approaches the Commonwealth and with it, increasing
cloud cover and rain chances, not expecting overnight lows to drop
as low as they did last night. At this time, valleys in the upper
50s and ridges in the lower 60s seems reasonable. Sent a new ZFP
to account for the changes in PoPs. Updates have been sent to NDFD
and to the web.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 518 PM EDT SAT OCT 5 2019
Models remain in good agreement for the short term period. To that
end the HRRR has even trended back the late afternoon and early
evening shower activity across our area, with activity showing up
later in the evening and/or during the overnight period.
Two features of interest appear in the short term. Weak, almost
sheared out short wave energy that will pass through the Ohio
Valley tonight and then a long wave trough that will push through
the Midwest Sunday into Monday. Satellite and forecast soundings
show a decent surge of mid-level moisture aloft overnight
tonight. With moisture returning to the area, short wave energy
passing through the region should be enough to generate some
shower activity late tonight during the pre-dawn hours of Sunday.
MOS PoP are categorical across the board for tonight. CAMs also
have activity developing overnight. The NBM advertises likely
PoPs for late tonight as well. At this point seemed a bit hard to
ignore and decided to trend upwards with PoPs. This suggests that
there will be a round of shower activity leading up to dawn
Sunday and just after. There appears to be a relative lull in
activity thereafter until later in the day Sunday as the storm
system to our west moves into the Ohio Valley. Best chance for
rain still appears to fall within the Sunday night into Monday
time frame. PWATS continue to edge upward suggesting that there is
a better chance for a well needed soaking rain for our area. The
speed of the front through our forecast area continues to look
relatively slow but steady, entering eastern Kentucky by late
afternoon or early evening Sunday and exiting our area by early
afternoon Monday. This will help with rainfall totals in the sense
that we need the rain. Widespread totals continue to range
between one and two inches. Higher amounts appear to be centered
over the northwestern parts of our forecast area while the far
southeast may only see around an inch. Thunder still looks
possible Sunday afternoon into the early evening. Instability is
elevated but appears more robust now. There was also a hint of
instability late tonight. However decided to leave thunder out for
now as this is only a recent trend.
.LONG TERM...(Monday through Saturday)
Issued at 412 PM EDT SAT OCT 5 2019
A cold front will slowly be moving through the far SE portion of the
state and exiting to our SE during the day Monday. Finally, we will
see much needed rain along the frontal boundary throughout the day,
quickly cutting off behind the frontal boundary as winds become more
northerly and advect drier air into the region. That being said,
lingering moisture and upslope flow will continue slight chances
across the high terrain into Monday night, before a developing
shortwave will continue them again for the same location during the
day Tuesday.
Precip chances will finally exit the entire CWA by Tuesday night,
with broad high pressure taking hold from the Deep South through the
Great Lakes and New England. JKL`s location on the SE side of this
low will continue to invoke cooler and drier air for the CWA. Then
as the high continues to shift NE, we will eventually transition to
return flow by Wednesday night into Thursday. A small upper level
ridge also moving in for Wednesday and Thursday will help to enhance
temperatures theses days. Highs Monday and Tuesday will be in the
upper 60s to low 70s behind the front. By Wednesday and Thursday
temperatures will modify to the mid and upper 70s.
Heights will begin lowering again Thursday night. When the NBM was
run, the GFS and ECMWF were in very good agreement about the
development of a strong upper level low developing across the
central/north-central conus, then quickly progressing eastward. A
surface center of low pressure will also be in place, pulling a cold
front eastward into the state Thursday night and eastern KY during
the day Friday. Based on the agreement, the NBM pops seemed quite
low, so the initial idea was to increase them. However, soon after,
the new ECMWF run came in, and showed a considerable displacement of
the surface low to the SW of the previous run, and resultantly, a
major slow down to the frontal passage across the state. While it
does still have the passage and precip occurring, it is some 24 to
30 hours later than the GFS. Based on this, did not stray away from
what the NBM had for pops as solutions will likely continue to
change and therefore confidence remains low until they come back
into a better agreement for several runs. The good news is that 1.
ether way, it looks like there is at least agreement on another
round of much needed rain moving through the CWA. and 2. there is no
instability showing up along this front according to the GFS, so did
not see any need to include thunder in the forecast.
Once this front moves through, the tail end of the forecast period
will see another blast of cold air. If the GFS is correct on it`s
timing, Saturday morning could see some valley temps dropping into
the upper 30s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 822 PM EDT SAT OCT 5 2019
VFR conditions will generally be the story through the period. At
this time, a few isolated showers and thunderstorms have
developed in southeastern Kentucky, but this is expected to be
short-lived. Did include TSRA for LOZ for an hour or so since a
storm is progressing northeastward over London currently. Did not
mention thunder for the other TAF sites, but will continue to
monitor this over the next few hours. Another concern for the
overnight will be the development of a low level jet over the
central portion of our area, particularly over the JKL site
towards dawn. Expecting any LLWS concerns to cease by 14Z,
however. As the cold front progresses towards eastern Kentucky
tomorrow morning, showers will be on the increase. Some heavier
showers are likely in the morning, with a decrease in intensity
into the early afternoon. However, as the front passes over
eastern Kentucky by late afternoon, showers are expected to
intensify. There will even be the potential for some
thunderstorms. Although, with this being at the end of the
forecast period, have mentioned at least -SHRA for now. Some
reductions in VIS are also possible during this time.
South/southwest winds will generally be between 5 and 10 knots
through the TAF period, outside of any thunderstorms.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CGAL
SHORT TERM...RAY
LONG TERM...JMW
AVIATION...CGAL
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
946 PM CDT Sat Oct 5 2019
.UPDATE...
Issued at 936 PM CDT Sat Oct 5 2019
The cold front extends through northeast and central MO into
northeast OK at 02z. Within the last hour there has been an
explosion of showers between St Louis and Columbia with lesser
coverage extending towards central IL. This development appears to
be in response to weak forcing associated with a short wave trof
now centered through western MO and largely lift/moisture
convergence associated with the west-southwesterly LLJ. The
precipitation is expected to continue expanding into east central
MO and southwest Illinois the remainder of this evening into the
overnight hours and then shift slowly southward with the movement
of the cold front. While the precipitation has been void of
thunder thus far, an axis of MUCAPE between 500-1000 j/kg
coincident with the lift should eventually result in scattered
thunderstorms as well. The last NAMNEST and several HRRR runs show
this evolution. Also late tonight across southeast MO and
southern IL there will eventually be a tendency to start seeing an
anafront precipitation distribution with a shift in showers
behind the front.
Glass
&&
.SHORT TERM... (Through Late Sunday Night)
Issued at 333 PM CDT Sat Oct 5 2019
Large scale ascent associated with a shortwave trough was occurring
near an approaching cold front. This combination will support
periods of scattered to numerous rain showers and isolated to
scattered thunderstorms across parts of the area through Sunday
night. The most likely area for rain will tend to shift
southeastward with time in tandem with the cold front. By Sunday
morning, the cold front and trough will be oriented such that
H85 moisture convergence and right entrance region jet dynamics
will lead to increasing precipitation chances across the southern
part of the LSX CWA even while precipitation chances continue to
decrease across the northern CWA. Precipitation chances will end
on Sunday night after the trough axis has passed and the front has
moved farther south.
Overnight lows tonight will range from near normal across the
northwestern half of the LSX CWA (mid/upper 40s) to 5-10 degrees
above normal across the southeastern half (upper 50s to near 60).
The coolest temperatures are expected farther back within the
post-frontal air mass and within expected areas of clearing
overnight while the warmest temperatures are expected for those
locations which will remain within areas of clouds and
precipitation. Temperatures will remain near or slightly below
normal across the area for Sunday and Sunday night due to the
influence of N/NW winds around the eastern side of a high pressure
center.
Kanofsky
.LONG TERM... (Monday through Next Saturday)
Issued at 333 PM CDT Sat Oct 5 2019
The aforementioned high pressure center will shift eastward into
the central CONUS and Great Lakes, bringing quiet weather and keeping
temperatures near to slightly below normal across most of the
area. The high pressure center then moves towards the NE CONUS by
the middle of the week, and the resulting flow between this
feature and a developing low pressure system over the central
CONUS will bring a warmer air mass back into the region.
Model guidance is in agreement that this flow of warmer air will
act to sharpen a baroclinic zone which then eventually moves
through MO/IL as a strong cold front, but there are significant
timing differences between the models regarding the speed of the
parent cyclone and the cold front. These differences lead to low
certainty in the temperature and precipitation forecast for next
Thu through Sat. This forecast package reflects a
middle-of-the-road approach with a frontal passage on Thu/Thu
night, but an earlier or later timing is certainly possible given
that this feature has not yet developed and is still 5-7+ days
away from affecting our area.
Kanofsky
&&
.AVIATION... (For the 00z TAFs through 00z Sunday Evening)
Issued at 621 PM CDT Sat Oct 5 2019
The two main issues tonight are precipitation chances and lower
ceilings. As far as precipitation, there is going to be a chance
of showers and a spot storm across eastern MO into southwest IL
this evening into the overnight hours, first ahead of a cold front
and then immediately behind it. Now while there is a chance, I
have low confidence in the coverage which may be only isolated to
scattered. Thus in the St. Louis area terminals (including KSTL) I
just have a VCSH. There is a band of stratus resulting in MVFR
flight conditions ahead of the advancing cold front and this will
impact KCOU and KUIN this evening with clearing near 03z. The
stratus will move into the St. Louis terminals (including KSTL)
around 04z and bring a 4 hour or so window of MVFR flight
conditions. After the stratus clears the terminals, VFR flight
conditions should persist through the remainder of the forecast
period.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Melbourne FL
1005 PM EDT Sat Oct 5 2019
.DISCUSSION...
A frontal boundary continues to push southward from near JAX
extending offshore into the Atlc but is expected to stall over or
near Volusia county overnight then wash out on Sunday. Isolated
showers will continue to push onshore overnight with higher coverage
of showers pushing W/SW from the Atlc toward Volusia county assocd
with the frontal boundary.
There has been a flare up of convection along the front well
offshore St Augustine in an area of enhanced UVV producing
occasional lightning strikes. HRRR shows this convection weakening
as it approaches Volusia county overnight but an increase in E/NE
flow along the Volusia coast should enhance coastal convergence so
will maintain highest PoPs (40 percent) for coastal Volusia. The
best chance for lightning will be over the Atlc waters overnight but
will keep thunder mention for Volusia and NE Brevard.
Low temps will be very mild along the coast due to persistent
onshore flow in the mid to upper 70s with lower 70s interior.
&&
.AVIATION...
Mainly VFR through 00Z. Isold SHRA will push onshore overnight with
scattered coverage around DAB. Will handle with VCSH for now but may
need to add a TEMPO group for DAB with the possibility of TSRA.
&&
.MARINE...
The most significant changes were to start the Small Craft Advisory
for offshore Volusia a little earlier at 11 pm and add a Caution
headline for the nearshore waters of Volusia and Brevard as well as
offshore Treasure coast waters. Frontal boundary is forecast to
stall over the Volusia waters later tonight with an increase in
shower coverage along with isolated storms.
Tonight-Sunday (previous)...East-northeast breeze will increase to
15-20 knots overnight as a weak front approaches the area. Seas of 4-
5 feet this evening will increase up to 7 feet overnight in the
offshore waters north of Cape Canaveral. A Small Craft Advisory will
be in effect starting late tonight for the offshore waters, then
extending into the offshore Treasure Coast waters by Sunday
afternoon as seas of 7-8 feet build in.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 75 84 75 85 / 40 40 40 50
MCO 73 87 73 86 / 10 40 20 60
MLB 77 87 77 86 / 20 40 40 60
VRB 75 86 75 86 / 20 40 40 60
LEE 73 87 73 88 / 10 30 10 50
SFB 73 86 73 86 / 20 40 20 60
ORL 73 87 74 86 / 20 40 20 60
FPR 75 86 74 88 / 20 40 40 60
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 10 AM Sunday to 4 PM EDT Monday for
Sebastian Inlet to Jupiter Inlet 20-60 nm.
Small Craft Advisory from 4 AM Sunday to 4 PM EDT Monday for
Volusia-Brevard County Line to Sebastian Inlet 20-60 nm.
Small Craft Advisory from 11 PM Saturday to 4 PM EDT Monday for
Flagler Beach to Volusia-Brevard County Line 20-60 nm.
&&
$$
Kelly/Combs
Area Forecast Discussion
National Weather Service Marquette MI
748 PM EDT Sat Oct 5 2019
.SHORT TERM...(This evening through Sunday)
Issued at 458 PM EDT SAT OCT 5 2019
Water vapor imagery and RAP analysis show a vigorous shortwave
lifting across the eastern Dakotas into nw MN. Strong 850-700mb
moisture transport and theta-e adv has supported a band of shra
spreading e into Upper MI today, though shra have tended to diminish
as they outran better dynamics hanging back to the w.
Clouds/pcpn/lack of much insolation has kept winds in check today
despite 40-50kt low-level jet beginning to shift over the fcst area.
Gusts have been into the 20-30mph over land. Over Lake Superior,
gusts at the high obs platforms are up into the lower gale range
except over far western Lake Superior. Even the n central and
eastern buoys are gusting to near gales.
Vigorous shortwave will lift across Upper MI/Lake Superior/northern
Ontario tonight. As associated occluded front swings across the fcst
area and mid-level dry slot arrives, expect shra/dz to end from w to
e during the evening and into the early part of the overnight. With
cyclonic flow and the edge of deeper moisture brushing the nw fcst
area, there could be a few -shra thru the night across nw Upper MI,
but it really looks like the overnight will end up dry. Otherwise,
main concern will shift to wind for Lake Superior and the Keweenaw.
Biggest negative aspect for enhancing winds continues to be lack of
meaningful caa to mix low-level winds more efficiently. 850mb temps
are only fcst to drop 4 or 5C overnight with a trend to neutral or
weak weak waa during Sun morning. Another negative is that the low-
level winds are more of a wsw direction rather than the more
favorable wnw direction. However, favorable isallobaric wind
component (though pres rise/fall couplet is not especially notable
at roughly +3/+4 mb/3hr and -4/-5 mb/3hr) and potentially upwards of
40-45kt in the mixed layer suggest conditions across the Keweenaw
will be flirting with wind advy (sustained winds of 30mph or more
and/or frequent gusts 45mph or greater). Although fcst soundings
depict mixed signals on degree of mixing in the low-levels and thus
how strong sfc wind gusts may become, seems that a wind advy is
probably warranted for northern Houghton and Keweenaw counties
overnight into Sun morning.
With daytime heating on Sun deepening the mixed layer and with brisk
winds of 30-40kt in the low-levels, it will be a breezy day across
the fcst area. Gusts to 25-35mph should be the rule, except 30-40mph
on the Keweenaw. There may be a decent amount of sunshine during the
morning, especially in areas where w to sw winds are downsloping.
During the aftn, daytime heating, cold air aloft, mid-level trof
over the area, and an approaching shortwave late in the day will
likely lead to isold/sct shra development. Over the last 24hrs,
models have trended toward more of a signal for shra development.
Seems reasonable given the factors mentioned. Some models show maybe
a couple of hundred j/kg of MLCAPE. If that materializes, not out of
the question that there could be a few rumbles of thunder. High
temps will be near to a little above normal in the mid 50s to lower
60s.
.LONG TERM...(Sunday night through Saturday)
Issued at 350 PM EDT SAT OCT 5 2019
The main forecast concerns for next week are lingering gusty winds
over the Keweenaw Peninsula and lingering showers, especially over
the north half of Upper Michigan Sunday night into Monday. Attention
then turns to a late-season warm up next week ahead of an open wave
expected to lift north across the Upper Great Lakes, undergo
cyclogenesis and then occlude as it stalls out late in the
week/early next weekend. Ahead of the developing surface low, strong
warm air advection does look to boost day-time temperatures into the
50s and 60s, with mild overnight lows for this time of year.
Thursday night into next weekend is a time period to keep a close
eye on as the above mentioned system impacts the region. Still quite
a bit of uncertainty that far out, but the system does look like it
could be a wind bag and depending on the track of the system, as
previously mentioned, we could see the first snowflakes of the
season. Certainly, the potent system expected to impact the region
late next week/next weekend is something to keep a close eye on.
Sunday night into Monday morning - A shortwave digging south across
the region will bring with it a brief shot of weak cold air
advection. The combination of a lingering strong pressure gradient,
pressure rises, and incoming weak cold air advection will allow for
gust winds to linger over the west half of Upper Michigan, and near
the Great Lakes. The windiest location looks to remain the Keweenaw
Peninsula, where wind gusts of 30 to 35 mph will remain possible.
As for precipitation, the combination of synoptic lift and colder
air moving in from the northwest will bring scattered rain showers.
While cold air advection isn`t incredibly strong, there does look to
be a subtle, weak lake enhancement signal. Instability doesn`t look
impressive, but given the lingering gusty west to northwest winds
rain showers should push inland quite a bit across then north half
of Upper Michigan.
Monday through Thursday - As the main shortwave pulls off to the
northeast early next week, surface high pressure center down in the
southern/central Plains will build northward into the Great Lakes,
essentially shutting down any lingering precipitation on Monday. As
the surface ridge continues to move eastward, over the Northeast, we
will remain anchored between high pressure to the east, and an
elongated open wave/surface trough to our west. This will place us
under continued bouts of warm air advection and an enhanced pressure
gradient. Therefore, Tuesday through Thursday, expect a late-season
warm up accompanied by daily breezy southerly winds. Given the
pressure gradient in play, could also see the breezy winds linger
during the overnight hours next week as well.
Thursday night into next weekend - As longwave troughing exits the
northern Rockies and lifts across the Upper Mississippi Valley, the
open wave to our west will undergo cyclogenesis, as low pressure
looks to quickly develop and deepen as it slowly lifts northeast
towards the Minnesota/Lake Superior border. While it is a bit early
to discuss specific impacts, as mentioned above there is the
potential for this system to generate some strong, gusty winds.
Initially even though warm air advection will dominate and try to
keep things more on the stable/less mixy side, given the strength of
the pressure gradient and the deepening low certainly think we could
be looking at a period of gusty southeast to south winds on
Thursday/Thursday night. There is quite a bit of uncertainty among
the deterministic models as to when the stronger cold air advection
will wrap around the system as it occludes; therefore, depending on
when we start to see the colder air aloft move in winds will switch
around to the southwest and would have additional support for
stronger gusts.
As for precipitation during this time period, as the low deepens it
will bring with it one last surge of warm air advection, deeper
moisture and the next best chance for rain. Did back off on the
better chances for rain until late Thursday/Friday morning, but as
we get closer to the event depending on the speed/track of the
system this timing could change further. There are very subtle hints
within MUCAPE fields that some limited instability may develop, but
for now opted to leave thunder out of the forecast. As mentioned
above there is uncertainty in regards to when the system will
occlude and start to send that surge of colder air across the area.
Based on a few forecast soundings, it isn`t out of the question that
we could see some wrap around snow try to work into far western
parts of Upper Michigan. Don`t expect any lake component at this
point given the predominately southwest flow regime we will remain
under into early parts of the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 743 PM EDT SAT OCT 5 2019
Ahead of an approaching occluded front, MVFR conditions with ocnl
light shra will likely prevail into the evening hrs at KIWD and
KCMX. However, under upsloping southerly winds at KSAW, IFR cigs
may prevail there this evening. Low-level jet will be translating
across the area thru early evening, but it appears there will be
sufficient mixing in the lower 2kft to preclude LLWS in the fcst.
With the passage of occluded front tonight, expect improvement
from w to e with all terminals becoming VFR by sunrise Sun.
Upsloping westerly wind will hold in MVFR cigs longest at KCMX.
Passage of front will also bring strong/gusty winds to KCMX under
favorable w wind direction. Gusts to 35-40kt are expected at that
terminal, but there could be a couple of hrs of higher gusts
immediately after fropa.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 458 PM EDT SAT OCT 5 2019
On Lake Superior, winds have been ramping up today, especially
across the central and eastern part of the lake where gusts have
reached the lower gale range this aftn. As deepening low pres
currently over nw MN lifts ne to southern Hudson Bay by Sun evening,
associated front will sweep across Lake Superior tonight. Ahead of
the front, the s to se winds over central and eastern Lake Superior
will continue to increase this evening with gusts reaching up to
40kt. Behind the front, winds will switch to the sw to w and ramp up
over western Lake Superior. Gusts to 40-45kt still appear likely
over the w half of the lake, but especially btwn nw Upper MI and
Isle Royale. Around the w and n side of the Keweenaw, wind gusts may
just reach storm force at times btwn 06z-12z Sun. Across eastern
Lake Superior, the w to sw winds behind the front will not be as
strong as over the w, gusting to 35-40kt. Winds may be a little
slower to subside blo gale force Sun aftn/evening, so gale warnings
may need to be extended across central and eastern Lake Superior
into Sun evening. Winds will diminish more notably overnight Sun
night thru Mon as sfc high pres ridge approaches. Winds should be
mostly under 15kt by Mon evening. S winds will then increase on Tue
with gusts reaching up to 25kt in the aftn. Winds will change little
for Wed. The next low pres system will approach on Thu, leading to
the potential for stronger winds late Thu into Fri.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Wind Advisory from 2 AM to 11 AM EDT Sunday for MIZ001-003.
Lakeshore Flood Advisory from 4 AM to 5 PM EDT Sunday for MIZ001-
003.
Lake Superior...
Gale Warning until 1 PM EDT Sunday for LSZ248-267.
Gale Warning until 9 PM EDT Sunday for LSZ264-266.
Gale Warning until 2 PM EDT Sunday for LSZ246-247-265.
Gale Warning until 10 AM EDT Sunday for LSZ249>251.
Gale Warning until 3 PM EDT Sunday for LSZ245.
Gale Warning until 11 PM EDT Sunday for LSZ244.
Gale Warning from 1 AM EDT /midnight CDT/ to 1 PM EDT /noon CDT/
Sunday for LSZ241.
Gale Warning from midnight EDT /11 PM CDT/ tonight to 6 AM EDT
/5 AM CDT/ Sunday for LSZ240.
Gale Warning from 1 AM to 11 PM EDT Sunday for LSZ242-243.
Gale Warning from midnight EDT /11 PM CDT/ tonight to noon EDT
/11 AM CDT/ Sunday for LSZ162.
Gale Warning from midnight tonight to 6 PM EDT Sunday for LSZ263.
Lake Michigan...
Gale Warning until 3 AM EDT Sunday for LMZ248-250.
Gale Warning until 1 AM EDT Sunday for LMZ221.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Ritzman
AVIATION...Voss
MARINE...Rolfson