Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/12/23
Area Forecast Discussion
National Weather Service Denver/Boulder CO
849 PM MDT Wed Oct 11 2023
.KEY MESSAGES...
- Wintry weather and hazardous travel for the mountains starting
this evening, continuing through Thursday night.
- Windy with high winds late Thursday through Friday morning
impacting the plains.
- Rain showers likely (60-70% chance) across much of the plains
Thursday and Thursday night, with a wintry mix at times,
especially for northern plains and Palmer Divide (minimal
accumulations).
- Hard freeze/end of growing season expected for most areas Friday
night. Near or below freezing temperatures as early as Thursday
night for the eastern plains.
&&
.UPDATE...
Issued at 836 PM MDT Wed Oct 11 2023
A few bursts of mountain snow have provided the first inch or two
of accumulation across the mountain peaks over the past several
hours. Based off CDOT cameras, it looks like snow levels have
dropped as low as about 9500ft during some of the stronger
convective bursts, but for the most part accumulations have
generally been at or above 10500-11000ft. Would expect another
couple of rounds of moderate to heavy snow showers traversing the
high country overnight, with high resolution guidance largely in
agreement on evolution but not the timing. Have adjusted the PoPs
through tomorrow morning to try to capture the more
convective/showery activity... with the heavier orographic snow
likely developing between 15-18z tomorrow.
Meanwhile, showers have been a bit more robust than forecast
across the lower elevations, likely aided by good upper level
divergence from the nearby jet streak. The best divergence is
moving off the urban corridor and satellite/radar show diminished
upstream activity, so I`d imagine that showers decrease pretty
quickly over the next few hours... with perhaps another round
tomorrow morning.
For now, we`ll let the current highlights continue as is... as
everything appears to be on track. I did contemplate expanding
the High Wind Watch tomorrow into Friday into Weld/Morgan counties,
but will hold off on that and let the overnight shift take a
deeper dive into the forecast.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 1257 PM MDT Wed Oct 11 2023
No significant changes to the ongoing forecast as the timing/track
still appear to be on track. Showers and thunderstorms popping in
the mountains this afternoon, with the greatest lightning
activity along the northern border, in closer proximity to the
upper low. The models still appear for the most part to move the
closed low along the northern border overnight, with it near the
CO/WY/NE triple point by 12z Thursday. The NAM12 is a little
further south but this appears to be an outlier at this time. The
RAP brings a moderate area of QG ascent along the northern border
overnight,with moderate to strong QG descent over the southern and
western part of the forecast area by 15Z Thursday morning.
On Thursday, much cooler with the closed low progged to lift into
central NE Thursday afternoon. The best chance of showers across
the plains will be tonight and Friday morning, with decreasing
pops from west to east Thursday afternoon. In the mountains, main
forcing mechanism will likely by orographically driven in the
afternoon favoring the northwest facing slopes. Strong subsidence,
an increasing surface pressure gradient and favorable instability
from the surface to 700 mb layer should allow for gusty northwest
winds increasing in the afternoon, strengthening more Thursday
night.
.LONG TERM...(Thursday night through Wednesday)
Issued at 1257 PM MDT Wed Oct 11 2023
By Thursday evening, the upper level low will be traversing the
plains into Kansas and Nebraska, ushering in colder air under
brisk northerly winds. Winds will be strongest during the Thursday
evening and overnight timeframe, and the current timing and extent
of the High Wind Watch remains appropriate. Snowfall intensity
will start diminishing as we enter the overnight period and
favorable jet dynamics are displaced well to our east.
Orographically-enhanced snowfall will continue in the high
country however (most pronounced over our northern mountains), and
light precipitation across the lower elevations should begin to
transition to snow or a rain/snow mix over the Cheyenne Ridge and
Palmer Divide mid to late evening. Given generally light intensity
and the likelihood that road temperatures will be playing catch-
up, accumulations shouldn`t amount to much more than a dusting for
these areas. A few flakes may certainly mix in overnight into
early Friday morning for almost any location as temperatures lower
into the low to mid 30`s, but accumulations outside of the
aforementioned areas are not expected. Most if not all of the
shower activity will be out of our area by daybreak Friday.
Winds will take a little longer to leave us however, with gusty
north winds continuing much of the day Friday across the plains,
and gradual weakening throughout the day. In the wake of this
system, chilly conditions will take hold with highs mainly in the
low 50`s - the coolest day of the week and between 10 and 15
degrees below normal for this time of year.
Upper level ridging will subsequently begin to build into the
weekend, but not before the more stable air mass and increasingly
clear skies allow for a more widespread freeze Friday night for
the plains and urban corridor. Areas that did not experience a
freeze last Saturday may do so this time around, with the only
uncertainty in sub-freezing temperatures focused over portions of
the urban corridor adjacent to the foothills and immediate Denver
metro. Past Saturday morning however, our warming trend will
commence, and we should return to near-normal temperatures around
Sunday or Monday. The milder temperatures will be accompanied by
overall tranquil weather, with a fair amount of sun each day and
no precipitation through at least Monday. Ensemble guidance
suggests moderate (30-40%) potential for another system to impact
the region in the Wednesday/Thursday timeframe.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 535 PM MDT Wed Oct 11 2023
Some lingering VCSH/-SHRA will persist near the terminals for the
next couple of hours before diminishing after 03z. Winds should
weaken but maintain a west-northwesterly component, eventually
transitioning to a light drainage flow overnight. There may be a
brief period of showers again Thursday morning, with some lower
cigs also accompanying any rain, but confidence is still low.
Winds should pick within an hour or two of 18z tomorrow, with
strong west-northwest gusts continuing most of the day into the
evening. Potential for some stronger north-northwest gusts of
30-35kts after 21z. Another conditional threat of showers and
lower cigs returns tomorrow afternoon into the evening but most
guidance keeps things dry.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 AM MDT Friday for COZ031-033-034.
High Wind Watch from Thursday afternoon through Friday morning
for COZ046>051.
&&
$$
UPDATE...Hiris
SHORT TERM...Cooper
LONG TERM...Rodriguez
AVIATION...Hiris
Area Forecast Discussion
National Weather Service Cheyenne WY
947 PM MDT Wed Oct 11 2023
.SHORT TERM...(This evening through Thursday night)
Issued at 500 PM MDT Wed Oct 11 2023
KEY MESSAGES:
* Widespread showers with embedded thunderstorms are ongoing this
afternoon with a marginal threat for gusty winds continuing
through the evening.
* A rapid transition to more wintry weather is on track for tonight
through the day on Thursday, with rain transitioning to snow for
much of the area and strong gusty winds expected.
* The main changes from the previous forecast include an increase in
snow totals along the Pine Ridge, a High Wind Watch for the
eastern row of counties in the NE panhandle and I-80 corridor, and
new Winter headlines west of the Laramie range.
THIS AFTERNOON AND TONIGHT: Currently, our area is in the warm
sector of the approaching storm system approaching from the
northwest. Showers and thunderstorms are flaring up along the
frontal boundary pushing across our western counties at this time.
RAP analysis indicates a surface low located over east central
Colorado at 988 mb MSLP at this time, with a surface pressure trough
extending north along the front range up towards a secondary low
near Casper. Surface pressure is rising near Rawlins with breezy
westerly winds. Through tonight, expect numerous showers with some
embedded thunderstorms to continue to move across the area,
eventually concentrating more across the northern part of the
forecast area later tonight. Initially, this will be forced mainly
by frontogenesis along with some marginal instability around 500
J/kg of CAPE. The 700-mb circulation center is currently nearly
located over the dead center of Wyoming, and this will slowly
traverse southeastward tonight. On the north side of this, expect
decent isentropic lift to help maintain shower activity through the
night overtop the stalled surface front that is expected to stretch
across the area. On the south side, dry air advection and isentropic
descent should work against precipitation for the I-80 corridor
(expect the higher elevations where orographics favor lift). Thus,
decreased the PoPs quite a bit for the I-80 corridor through early
Thursday morning, but maintained very high PoPs for areas generally
along and north of the North Platte River.
THURSDAY AM WINDS: This may also set up a sharper surface pressure
gradient over the South Laramie Range gap. Most guidance indicates a
cross-barrier pressure gradient of about 4 MSLP, which is on the low
side for reaching high wind. The stronger pressure gradient is
generally just to the south, as mentioned in the previous forecast
discussion. Still, northwest flow and 700-mb winds approaching 50-
knots suggest the potential for some locally higher winds near the I-
80 summit, which can tend to over perform in these setups. The
summit zone may see snow kicking up earlier than further east with
favorable orographics, so decided to include the wind messaging
in the Winter Storm Warning headline. For the foothills and
central Laramie county, there is a very marginal threat for high
wind during the WNW initial phase Thursday morning, and then
another period of concern during the NNW winds Thursday afternoon
and Thursday night. Therefore, decided to go for a High Wind Watch
for these areas, starting at 12z and continuing through Thursday
night.
WEST OF LARAMIE RANGE: The trough axis clears to the east of the
area tonight, and we move into the cold sector of the system by
Thursday morning. Moist air advection aloft in the wrap-around flow
along with isentropic lift will enhance precipitation activity over
our western counties late tonight, mainly after 3AM. Forecast
soundings indicate that this round should flip over to snow pretty
quickly with 700-mb temperatures around -2 to -3C in Carbon county.
Thus, have almost everyone west of the Laramie range in at least
rain/snow mix by sunrise Thursday. Temperatures will likely
fluctuate from slightly below freezing to slightly above freezing
depending on immediate precipitation rates in the valleys of Carbon
and Albany counties. Therefore, decided to issue a Winter Weather
Advisory for central/northern Carbon county and the Shirley Basin.
While amounts are very likely to exceed warning criteria in some
parts of the zone, impacts for the populated locations and the
highways look to be generally advisory level. Thus, expecting a
widespread 2 to 6 inches, but some higher elevations above 7500
feet could easily reach the 6 to 12 inch range. Winds become more
northerly across the area Thursday afternoon, which is a good
upslope direction for Arlington and Elk Mountain. Model QPF has
trended up here, with most of the precipitation after Thursday AM
expected to fall as snow. Thus, had the confidence to issue a
warning for this zone with some 6 or more inches likely over
portions of I-80. Amounts will decrease rapidly heading north to
Rock River and Medicine Bow, but impacts may be warning level
along the highway. One final think to watch out for in later
updates is the Saratoga and Laramie valleys. NNW winds are one of
the only wind directions that don`t shadow these valleys. While
current QPF expectations are modest, HiRes models are fairly
aggressive on snow accumulations here, so later shifts may need to
consider headline expansion.
EAST OF LARAMIE RANGE: By 12z Thursday, the surface cyclone will be
wrapping up over central Nebraska with the surface trough/frontal
boundary stretching back to the northwest towards the Bighorn
mountains of north central Wyoming. Once the synoptic trough/upper
level low ejects over the High Plains, expect this stalled boundary
to then surge back to the south, bringing cold air advection and
northerly winds to the area. The wrap-around flow and isentropic
lift then extends further south also, leading to precipitation
filling back in late Thursday morning through the afternoon to the
south. Models have generally come into better agreement on this as
the GFS wobbled back to the south in line with the ECMWF and most
HiRes guidance. Expect the rain/snow transition to begin in the late
morning, with higher elevations of Converse, Niobrara, and Sioux
counties seeing snow first sometime. Snow levels continue to drop as
colder air pushes southward, so by 00z Thursday, expect most of the
higher elevations along the Cheyenne and Pine Ridges to at least be
mixing with snow. Strong northerly winds will likely lead to
significant visibility reductions. Since we still have a little bit
of time on this, held off for any winter headline issues over the
High Plains, but if trends hold going forward, Winter Weather
Advisories will likely be needed for some zones, with wording
indicating higher potential for accumulation above about 4500 feet.
Will let the next HiRes model cycle be examined, since impacts will
likely hold until at least after noon, but more likely beginning
around 3-6PM. The main change with this forecast package was an
increase in snow over the Pine Ridge, where HiRes models are in
fairly good agreement now showing the potential for around 6 inches.
This area benefits from northerly upslope flow and will be near the
coldest part of the storm to draw in some lower snow levels. Lastly,
a very strong MSLP gradient will be in place over the high plains
Thursday afternoon and Thursday night as the main system wraps up
and ejects to the east. Even though the strongest winds aloft are
after dark, forecast soundings show a well-mixed boundary later,
with the HRRR in particularly indicating the potential for gusts
exceeding 50 knots. While it looks marginal due to the nocturnal
timing and winds aloft just barely reaching 50-knots, thought there
was enough evidence for a High Wind Watch for the eastern row of NE
panhandle counties and the I-80 corridor.
Expect a cool and breezy day Friday with clearing skies as the
system departs to the east.
.LONG TERM...(Friday through next Wednesday)
Issued at 430 PM MDT Wed Oct 11 2023
No major changes to the long term forecast with this update. See
previous discussion for more details:
PREVIOUS DISCUSSION:
Minimal changes made from the NBM for the long term forecast.
Ridging takes over following the trough passage bringing zonal flow
back to the forecast area with temperatures gradually warming each
day. Temperatures Saturday and Sunday may trend lower with later
forecast packages depending on how much snow falls Thursday and
Friday. In areas that receive more snowfall and that snow sticks to
the ground, temperatures will not rebound quite as well as in areas
where the snow melts rapidly.
Long range models begin to diverge in solutions Monday where the GFS
has a shortwave dropping south, bringing precipitation chances. The
ECMWF merely has the ridge elongating and shifting east, keeping
southeast Wyoming and the Nebraska panhandle high and dry. Next
signal for a deeper trough comes into the forecast Tuesday night
into Wednesday, but that is still 7-8 days away, so we will wait and
see how the pattern develops.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 940 PM MDT Wed Oct 11 2023
A potent weather disturbance aloft will bring widespread rain, snow
and fog to the terminals, along with brisk winds at times.
Wyoming TAFS...Occasional showers will affect the terminals
producing ceilings from 1500 to 2500 feet AGL at times, along with
visibilities from 2 to 4 miles. Winds will gust to 25 knots at
Rawlins from 16Z to 00Z, to 32 knots at Cheyenne after 13Z, and to
30 knots at Laramie after 18Z.
Nebraska TAFS...Occasional showers will affect the terminals,
reducing visibilities to 1 to 4 miles along with ceilings from
1200 to 2500 feet AGL. Winds will gust to 42 knots at Chadron and
Alliance after 08Z, and to 40 knots at Scottsbluff and Sidney
after 16Z.
&&
.FIRE WEATHER...
Issued at 430 PM MDT Wed Oct 11 2023
Little to no fire weather concerns throughout the week with
widespread precipitation expected through Friday. Precipitation
chances are expected to decrease into the weekend, with wind
speeds increasing to around 20 mph. However, minimum humidity
values are expected to remain above critical thresholds.
Precipitation chances resumes by next week.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch from Thursday afternoon through Friday morning
for WYZ119.
Winter Storm Warning from 6 AM Thursday to 6 AM MDT Friday for
WYZ103-110-116.
Winter Weather Advisory until 6 AM MDT Friday for WYZ104-105-109.
Winter Weather Advisory from 6 AM Thursday to 6 AM MDT Friday
for WYZ106.
Winter Storm Warning until 6 AM MDT Friday for WYZ112-114.
High Wind Watch from 6 AM MDT Thursday through late Thursday
night for WYZ117-118.
NE...High Wind Watch from Thursday afternoon through Friday morning
for NEZ002-003-020-021-054-055.
&&
$$
SHORT TERM...MN
LONG TERM...LEG
AVIATION...RUBIN
FIRE WEATHER...MRD
Area Forecast Discussion
National Weather Service Des Moines IA
704 PM CDT Wed Oct 11 2023
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Wednesday/
Issued at 301 PM CDT Wed Oct 11 2023
Key Messages:
-Rain and storms likely through the rest of the work week,
especially for northern Iowa. Some storms overnight tonight and
tomorrow night could be strong to severe with hail tonight and
winds tomorrow night.
-Gusty winds likely Thursday night.
-Cool conditions through the weekend into early next week.
A period of wet weather began overnight into this morning with a
lingering LLJ influenced line of showers and some thunderstorms
veered east during the morning. As the lee side disturbance began to
deepen, southerly flow near the surface intensified, bringing
additional rounds of rain to portions of southern Iowa. This warm
front will lift through the day and reach northern Iowa. With the
profile`s moisture being shallow and focused in the lower
atmosphere, not much coverage of rain expected through the day. As
the evening and overnight hours commence, the LLJ will reintensify
in southwest Iowa and provide deeper saturation once again. The main
challenge in rain tonight is the placement of the warm front
relative to the LLJ max. Models indicate displacement between the
two boundaries, and consequently a question as to which boundary
will have more associated rainfall with it. This is the explanation
for the jump in precipitation location in recent model runs (the 06z
and 12z HRRR being great examples in this). Highest confidence is in
the main moisture axis with the LLJ further south, but have kept
broad PoPs in the northern half of the area to reflect the change
for rain associated with the front as well. PoPs coverage may very
well be overdone for the overnight period due to the uncertainty. A
stronger updraft that is able to initiate along the boundary may be
able to produce marginally severe hail.
Daytime rain on Thursday will once again be focused along the
boundary in northern Iowa during the day with the main low center
deepening over Nebraska. Favorable wind shear profiles in place for
organized severe weather as the system moves eastward, but it
arrives in central Iowa late Thursday night when the instability
axis is lost. Still, with a strong enough wind field in place, gusty
winds may accompany storms as they enter the state. Synoptic winds
will already be strong without the added influence of convection
with winds up to 40kts in northern Iowa. A Wind Advisory will be
needed and will likely be issued in the next forecast issuance. As
with previous shifts, have blended in guidance to correct the high
wind gust guidance in the NBM.
On Friday, instability will build back along the cold front and
reinvigorate the convection that will be moving across the state,
allowing them to reorganize. The risk for severe weather will
primarily be east of the area, but a strong storm in the southeast
cannot be ruled out as storms strengthen over the area. Overall, the
rainfall from the event remains unchanged: 1-3" possible for areas
that remain under the influence of the warm front with locally
higher amounts possible from convection. The highest QPF will be
along the deformation axis which will remain north and west of the
area.
As the weekend commences, lingering showers from the exiting system
will be the feature for Saturday with gusty winds returning. The GFS
develops a trailing shortwave that could continue to support showers
through the afternoon. Trends will be monitored. The trough will
stall over the eastern CONUS and keep our area in northerly flow and
keep our temperatures seasonably cool for the start of next week.
&&
.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 646 PM CDT Wed Oct 11 2023
Main aviation concerns through the TAF period will be rounds of
showers and thunderstorms. Timing in TAFs is geared towards the
near term with additional TSRA/VCTS mentions likely needed in
future issuances. CIGs expected to fall towards at least MVFR if
not IFR overnight into tomorrow, especially for northern
terminals, with some visibility reductions at times in the
vicinity of showers/storms. Winds out of the east to southeast
will also be breezy at times with winds turning particularly gusty
later Thursday into Thursday night.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Jimenez
AVIATION...KCM
Area Forecast Discussion...UPDATED
National Weather Service Quad Cities IA IL
818 PM CDT Wed Oct 11 2023
.MESOSCALE UPDATE...
Issued at 818 PM CDT Wed Oct 11 2023
We continue to monitor an isolated strong to possibly severe hail
threat along with occasional gusty winds through early overnight,
as well as an isolated local heavy rainfall threat north of I-80.
A surface warm front is positioned near the Iowa/Missouri border
early this evening, with a 35 kt low-level jet extending north of
this providing warm advection aloft and an increasing nose of
MUCAPE of 500-1,000 J/kg up to I-80 per the latest SPCOA RAP
(unfortunately no 00Z DVN sounding due to lightning). This along
with increasing mid-level flow to 45 kt has kept elevated storms
persisting along/north of the I-80 the last few hours. Effective
shear aloft of 35-45 kt along with veering flow in that layer has
been plenty sufficient for strom organization, and many of the
storms produced at least small hail, with a couple more sustained
ones yielding hail to 1.5 inches. As an aside, these have had
evenly spaced storms and had shape characteristics showing they
may have been rooted on gravity waves, which can happen with a
strong low-level inversion north of a warm front. Sometimes these
storms can spike, including recent research showing they can
produce winds to the surface (such as experienced here in the
Quad Cities with gusts of ~40 mph). So will need to watch for that.
Overall, scattered storms are expected to continue along the
elevated 850 mb moisture/MUCAPE gradient through at least early
overnight if not the entire night, mainly along/north of I-80.
Marginally severe hail, and some gusty winds especially in any
linear-like features, as well as sharply reduced visibility in
heavy rainfall, are the main threats. While the frontal zone
aloft will not shift much and provide for some f-gen induced
heavy rainfall, the flash flooding threat does not look high given
1.) smaller convective footprints thus far, 2.) the moisture
transport/deep layer moisture convergence not being overly high in
magnitude, and 3.) antecedent very dry conditions north of I-80,
&&
.SHORT TERM...(This evening through Thursday)
Issued at 132 PM CDT Wed Oct 11 2023
Key Message:
1) Multiple rounds of showers and thunderstorms can be expected
through the next 24-36 hours. Bulk of the rainfall will fall in this
time period, with 1-2"+ possible.
This Afternoon and Tomorrow...
A weak leading shortwave continues to push through the area this
afternoon and into the evening. This has been tracked through much
of the day, seeing light rain showers and embedded thunderstorms. An
associated boundary will stall out in our north this evening, which
will be the next focus for heavy rainfall. Areas along and north of
Highway 30 will see the best chance for rounds of repeating
thunderstorms through the evening and tonight. At the same time, we
will also see the warm front associated with the parent shortwave
move in from the south. This will serve as another forcing mechanism
for showers and storms. At this point, we will start to see strong
warm advection kick in. Thus, increasing temperatures and moisture
will be seen, with a stout inversion developing aloft. This will
help keep thunderstorm activity elevated. Although, we can expect
some strong to severe storms, with the main hazard being large hail.
For this reason, the SPC has highlighted much of our area in a
Marginal Risk (level 1/5) for severe weather tonight.
As was mentioned, we can expect to see better rainfall rates and
higher accumulations in storms tonight. This will result from the
strong moisture advection, pooling moisture along the warm front.
PWATs tonight may range between 1.00-1.25" along the boundary. Where
the boundary and resultant thunderstorms develop, this will be where
the axis of heaviest rainfall will likely be seen. Although, there
remains uncertainty on how far north the front will push overnight,
which directly will impact where the heaviest rainfall will set up.
As was mentioned, along/north of Highway 30 is where much of
guidance has favored. Although, if the boundary remains farther
south with a strong LLJ pumping into it, we may see the storms
develop a little farther south towards Interstate 80. This will be
watched closely and we will continue to mention any changes in
the forecast as new details emerge.
Breezy conditions will also be seen tomorrow, as gradient winds
increase through the day. Currently, we are forecasting easterly
winds (southerly, south of the warm front) around 15-20 mph, gusting
upwards to 35-40+ mph. With such a strong jet core aloft, wouldn`t
be shocked to see a few gusts on the higher side of that range. With
that, the temperature forecast is a little tricky as well. This will
depend on the progression of the warm front. Areas south of the warm
front (currently looking at the Highway 34 corridor and south) will
see unseasonably warm temperatures, reaching the mid to upper 70s.
Those north of the boundary will see brisk easterly winds and
clouds, keeping temperatures in the upper 50s to low 60s, as we
approach the front.
Pack those umbrellas!
.LONG TERM...(Thursday night through Wednesday)
Issued at 132 PM CDT Wed Oct 11 2023
Key Messages:
1. Active weather pattern continues, bringing several chances for
precipitation and below normal temperatures by the end of the week.
2
2. Breezy conditions will be seen through the end of the week and
into the weekend. Winds between 10-20 mph throughout much of the
long term can be expected, with higher gusts expected (especially
Friday).
Discussion:
Thursday Night and Friday...
Thursday night and through Friday, surface low starts it trek east,
towards our area. By midnight, we will see PoPs increase from the
west, completely covering the area by mid-morning on Friday. Then,
this precipitation will continue through much of Friday, finally
getting cutoff Friday evening/night by the crashing cold front.
Through the night, we will see PWATs increase to 1.25-1.50"
throughout the area, especially right ahead of the approaching cold
front. Strong warm advection will favor the increasing PWATs, which
would place us around the 90th percentile or higher for this day,
compared to climatology. These PWATs have trended a little higher
than previous model runs, which would increase precipitation rates
in thunderstorms. Thus, we can expect heavy rain potential as
precipitation moves through the area. While wrap around
precipitation may continue beyond, accumulation from those showers
will be low, as drier air filters in.
Confidence is increasing in storm total precipitation, but there
remains some uncertainty. Currently, WPC guidance is highlighting an
event total widespread rainfall between 1.00-3.00" of rain, with
highest totals in the north. Ensemble guidance remains lower than
deterministic guidance. Probabilistic guidance does not favor more
than 2.00" of rain for much of the area, but does favor greater than
an inch. Better probabilities hint at a widespread 1.00-2.00"
rainfall, with some areas seeing locally higher amounts, when all is
said and done. While our confidence remains low on the higher end of
the rainfall, due to inconsistencies amongst guidance, these totals
will be in the realm of possibilities. Currently, the best bet for
the heaviest precipitation axis will be along/north of Highway 30,
in the end. Best rain chances on Friday will be along the
approaching cold front and expand north/south along the front. This
will be quite the swath of rainfall, which can be heavy at times.
Although, this will move out of much of the area by mid-afternoon,
leaving us with back-end showers.
Strong shear moving in, associated with the system, may balance with
the little bit of instability that we have to develop strong to
severe storms. This is a conditional threat and will revolve
around how much instability we build up. Shear will range between
30-50 KTs, with low level shear between 20-30 KTs. Thus, we must
keep an eye on the small scale features, which can lead to a
heightened threat. The feature that we will be watching is the
occluded front and how these boundary intersections can impact our
area, especially if we build instability. Bulk of the showers and
storms move through the area before noon. Thus, the timing of
fropa is not in favor of severe weather, climatologically.
Weekend and Beyond...
Cold front crashes through the region, leaving us in a cold post-
frontal airmass. We will continue to see the chance for isolated-
scattered showers through the weekend, resulting from residual
energy gyrating around the passing upper low. Also, we will see
another wave approaching from the northwest early next week, which
will continue the chances for precipitation. Overall, we will
remain in the northwest flow pattern, which will keep us in the path
of shortwaves and under cold advection. With this flow regime, we
will also see temperatures plummet. Saturday and onward, we trend
below normal on temperatures, with daytime temperatures in the low
50s for many, and nights in the 30s once again. To make it feel even
cooler, gusty northwest winds will be seen through the weekend and
early next week, adding a little more chill to the air.
Keep those jackets and umbrellas handy!
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 640 PM CDT Wed Oct 11 2023
A warm front will lift slowly northward over the next 24 hours and
bring rounds of showers and storms followed by low clouds to all
sites except KBRL. This should be variable conditions this evening
predominantly VFR outside of precipitation then going to bouts of
MVFR/IFR in the showers and storms. Small hail will be possible
with any storms. Eventually, more widespread MVFR/IFR conditions
expected in lingering precipitation but also low cloudiness.
As the warm front lifts through on Thursday, anticipate
improvement to widespread MVFR and VFR by afternoon. Winds will be
gusty at times from E/SE at 10-20+ kts.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...Friedlein
SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...McClure
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
701 PM CDT Wed Oct 11 2023
...New UPDATE...
.UPDATE...
Issued at 701 PM CDT Wed Oct 11 2023
Made an update this evening to increase the coverage of fog in the
forecast grids for tonight through mid-morning tomorrow as most
near-term guidance shows a decent coverage of reduced visibilities at
or below 5SM with some isolated areas of visibilities around 1SM.
-Gale
&&
.SHORT TERM...
(Tonight through Thursday night)
Issued at 226 PM CDT Wed Oct 11 2023
Synopsis/Mesoanalysis: GOES water vapor imagery and ACARS soundings
are showing a west to east drying trend in-progress early this
afternoon. Said drying trend, in tandem with a departing upper right
entrance region & area of surface cyclogenesis over the Gulf of
Mexico, has translated to precipitation departing east down the
Interstate 10 Corridor over the last several hours. Largely
precipitation-free conditions will prevail through the remainder of
the period in the wake of this activity, though patchy
drizzle/streamer showers will be possible during the predawn periods
over portions of Hill Country and the southern Edwards Plateau.
Currently evident across the Pacific Northwest, a broad area of
upper low pressure will translate quickly to the southeast through
tonight, approaching the lee of the Rocky Mountains by daybreak
tomorrow. Already apparent in Central & Southern Plains surface
observations, surface pressure falls & lee troughing will continue
to become better defined through this afternoon, with cyclogenesis
forecast to occur in the Central Plains by the mid-evening hours
tonight. The infant surface low will pivot east-northeast along the
KS-NE border vicinity through tomorrow morning, eventually occluding
as it enters the Missouri Valley nearing the end of the period. The
surface low will drag a cold front to the southeast in the process,
which will overtake a leading dryline as it progresses into the
state tomorrow night. The latest progs place the boundary along an
axis extending from the Red River southeast into the Edwards Plateau
by sunrise Friday morning, with progression into South-Central Texas
expected during the first periods of the long term.
Tonight: Expect low temperatures primarily in the mid-upper 60s
across the majority of the region. A few locations along the US-77
Corridor may bottom out in the lower 60s. Some patchy fog is
possible following midnight over portions of the Coastal Plains.
Additional patchy fog & drizzle/showers are possible over portions
of the southern Edwards Plateau and Hill Country closer to daybreak,
where the nocturnally-maximized & largely southerly low level jet
will be favorably aligned with the terrain of the Balcones
Escarpment. Measurable precipitation is not expected in any predawn
drizzle or light showers.
Thursday: Southerly winds, as well as significantly more afternoon
sunshine compared to today, will lead to milder high temperatures at
or just above normal areawide. The afternoon update shows widespread
readings in the mid-upper 80s across the region, with a few low 90s
expected along the Rio Grande. Have kept the forecast completely
dry, though the 12Z Wednesday run of the HRRR does suggest the
development of scattered streamer showers over the Coastal Plains
during the peak heating of the day. Have inserted some silent 10%
precip probabilities south of I-10 and east of I-37 in light of this
low end potential, and will continue to monitor trends for
potentially higher precip probs over the next 12 hours.
Thursday Night: Expect milder low temperatures relative to tonight.
Mid-upper 60s are forecast over Hill Country and the Coastal Plains,
with low 70s probable along the majority of the I-35 Corridor and
the Rio Grande. Similar to tonight, patchy fog, drizzle, and
streamer shower development is possible once more over Hill Country
and the southern Edwards Plateau during the predawn hours.
Measurable precip is not expected.
&&
.LONG TERM...
(Friday through Wednesday)
Issued at 226 PM CDT Wed Oct 11 2023
Friday a dry, Pacific cold front will move into South Central Texas.
Ahead of the front southeasterly flow will continue to push warm air
into the region. The front should reach our northern border by around
noon. In addition to the warm advection there will be compressional
warming ahead of the front. High temperatures will climb into the
upper 80s to middle 90s Friday before the boundary moves through. The
front should be across our southern border by the middle of the
evening. It looks like the only chance for precipitation will be over
the Rio Grande Plains and chances will be low. Cooler, drier air will
filter in Saturday. Lows and highs will be around ten degrees cooler
than Friday. As we suspected, the sky condition forecast is getting
more detailed with more cloud cover for Saturday. It`s starting to
look like there will be partly to mostly cloudy skies southwest of
the a line from the Rocksprings to Hondo. Northeast of there still
looks mostly sunny. High pressure will dominate over the region for
the remainder of this period keeping the weather dry and temperatures
fairly steady Sunday through Wednesday.
&&
.AVIATION...
(00Z TAFS)
Issued at 639 PM CDT Wed Oct 11 2023
MVFR cigs are beginning the period at most terminals which should
continue through the evening hours. Cigs are expected to become IFR
between 06-12z, and possibly as low as LIFR at KSAT/KSSF. Visibility
reductions as low as 1SM in BR will be possible as well, with the
lowest visibility expected around KSAT/KSSF. A slow, gradual
improvement in cigs/vis is then expected through the remainder of the
morning and into the early afternoon hours, with a return to VFR
conditions expected at all terminals by 12/20z. Southerly to
southeasterly flow will continue around 6-12 kts, with gusts to
around 20 kts possible during the afternoon and evening hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 66 88 69 92 / 0 0 0 0
Austin Bergstrom Intl Airport 65 88 70 92 / 0 0 0 0
New Braunfels Muni Airport 67 89 70 94 / 0 0 0 0
Burnet Muni Airport 66 87 70 89 / 0 0 0 0
Del Rio Intl Airport 69 93 72 95 / 0 0 0 0
Georgetown Muni Airport 65 87 71 91 / 0 0 0 0
Hondo Muni Airport 67 87 69 91 / 20 20 20 0
San Marcos Muni Airport 64 89 69 93 / 0 0 0 0
La Grange - Fayette Regional 63 87 69 89 / 0 10 0 0
San Antonio Intl Airport 68 87 71 91 / 10 0 0 0
Stinson Muni Airport 67 89 72 92 / 10 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...Quigley
Long-Term...05
Aviation...Gale
Area Forecast Discussion
National Weather Service Goodland KS
433 PM MDT Wed Oct 11 2023
.SHORT TERM...(This evening through Friday)
Issued at 115 PM MDT Wed Oct 11 2023
Scattered storms in Colorado this afternoon will weaken as they
move east this evening, but cannot rule out a sporadic stronger
wind gust as they decay after sunset. Best chances for any
measurable precipitation or wind will be north of Interstate 70.
Showers will lift into Nebraska after 06z. Otherwise expecting
partly cloudy skies and lows in the 40s and 50s.
Upper low will cut off over northeast Colorado Thursday morning,
drift east along the Kansas-Nebraska border during the day before
lifting into central Nebraska Thursday night. This system will
bring a variety of possible hazards to the area during that time.
Ahead of the upper low on Thursday, westerly winds gusting up to
45 mph will develop, mainly south of Interstate 70. These
downsloping winds will also bring much drier air into the region
from the west. Both the NAM and HRRR tank dew points into the
teens and 20s as early as 16z in western areas, spreading eastward
in the afternoon. As a result of the wind and low humidity, issued
a Fire Weather Watch for those areas. Precipitation will initially
be rather isolated in the morning, but scattered showers and
thunderstorms will develop in the afternoon with surface heating.
Moisture will be very limited with the dry line well to the east,
but a few stronger stronger high based storms will be capable of
producing wind gusts in excess of 50 mph. Given the proximity to
the closed upper low, cannot rule out a few funnels or brief weak
tornadoes either. The strong northerly winds will begin to wrap
around the low Thursday night, first in western areas during the
evening hours then the remainder of the area late Thursday night
through Friday afternoon. Both the GFS and ECMWF are showing wind
gusts in the 50-55 mph range during those times. Since those winds
are marginal for meeting high wind criteria, will leave the High
Wind Watch as it is and not upgrade at this time.
Friday will be windy with gradually clearing skies. Wind speeds
gradually decrease in the afternoon from west to east as the low
lifts out. Temperatures will struggle to reach the low to mid 50s,
and if clouds hang on at all may only see upper 40s. For Friday
night, some indications that wraparound cloud cover may move into
northern areas during the night. If that happens, lows will not
reach their potential and may only see mid to upper 30s there.
Further south and west, less clouds and lighter winds should allow
for radiational cooling and lows still forecast in the mid to
upper 20s west of Highway 27. Potential for cloud cover has
lowered confidence a bit and decided not to issue a Freeze Watch
for now. Only western areas are still susceptible to freezes,
since eastern areas had a hard freeze last weekend.
.LONG TERM...(Saturday through Wednesday)
Issued at 219 PM MDT Wed Oct 11 2023
The extended looks to be mostly dry with near-normal temperatures
across the area. As the approaching system exits the Great Plains
late Friday/Saturday, the Tri-State area is expected to be under
zonal to WNW flow aloft as an upper ridge moves east over the
Rockies. The ridge is expected to remain the dominant pattern
through early next week. The latest run of the GFS shows a few weak
disturbances moving over the North and Central High Plains overnight
Saturday into Sunday; however, it doesn`t look like these
disturbances should have an impact if they occur. Winds are expected
to be 5-15 from variable directions as the surface high moves over
the area. Model guidance has some disagreement over the pattern
Tuesday and Wednesday of next week. The GFS depicts a upper trough
swinging over the Northern and Central Plains on the backside of the
upper low while the ECMWF keeps the ridge strong over the area. For
now, not much has changed from the previous forecast for early next
week. Midweek there is potential for another upper low to move over
the Northern CONUS with a cold front moving over the Tri-State area
possibly Thursday. This could bring our next round of precipitation
depending on how the system tracks.
A nice blast of cold air is expected to move over the area this
weekend. Temperatures are expected to be in the mid to upper 50s on
Saturday with overnight lows in the upper 20s to lower 30s. Sunday
looks to be slightly warmer with highs in the 60s and lows in the
lower 30s. Monday currently is expected to be similar to Sunday.
Tuesday and Wednesday looks to be slightly above normal for highs
with temperatures in the mid 60s to lower 70s. Overnight lows are
expected to be in the upper 30s to lower 40s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 430 PM MDT Wed Oct 11 2023
GLD: VFR conditions will prevail tonight.. and through most of
the day on Thursday. MVFR ceilings are anticipated to rapidly
develop near the end of the TAF period (~00Z Friday). Southerly
winds at 10-20 knots this aft/eve will become variable overnight..
as a low pressure system in Colorado progresses ENE-NE over far
northwest KS and southwest NE. Winds will shift to the W-WNW at
10-20 knots late Thu morning / early Thu afternoon.. as the
aforementioned low progresses eastward into central
Kansas/Nebraska.. strengthening to 25-35 knots during the late
afternoon. Winds will veer to the WNW-NW and further strengthen to
30-45 knots Thu evening (00-03Z Fri) and persist well into the
day on Friday.
MCK: While VFR conditions will prevail through the (00Z) TAF
period.. MVFR ceilings are anticipated to rapidly develop tomorrow
evening (00-06Z Friday). S to SE winds at 10-20 knots this
aft/eve will become variable late tonight.. as a low pressure
system in Colorado progresses ENE-NE over far northwest KS and
southwest NE. Winds will shift to the W at 10-15 knots late Thu
morning / early Thu afternoon. A considerable amount of
uncertainty exists with regard to wind speed/direction mid-late
Thu afternoon. Winds could range anywhere from light/variable to W
at 20-30 knots.. depending on the track/evolution of the low
pressure system. Either way, at some point Thu evening (00-06Z
Fri).. winds will shift to the NW and strengthen to 30-40 knots
and persist well into the day on Friday.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...High Wind Watch from Thursday afternoon through Friday morning
for KSZ001>004-013>016-027>029-041-042.
Fire Weather Watch from Thursday morning through Thursday
afternoon for KSZ003-004-014>016-027>029-041-042.
CO...High Wind Watch from Thursday afternoon through Friday morning
for COZ090>092.
Fire Weather Watch from Thursday morning through Thursday
afternoon for COZ254.
NE...High Wind Watch from Thursday afternoon through Friday morning
for NEZ079>081.
&&
$$
SHORT TERM...024
LONG TERM...KMK
AVIATION...Vincent
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
842 PM CDT Wed Oct 11 2023
.SYNOPSIS...
Issued at 813 PM CDT Wed Oct 11 2023
A strong weather system will bring a few waves of showers and storms
tonight through Thursday, and again Friday and Friday night. There
is also the threat for a few strong storms and heavy rainfall.
Breezy winds develop on Thursday, but will stick around through
the weekend. Warm temperatures are expected tomorrow and in some
areas on Friday. However, cooler temperatures will arrive for the
weekend and into next week.
&&
.UPDATE...
Issued at 842 PM CDT Wed Oct 11 2023
A few showers and thunderstorms have developed in the vicinity
and north of a warm front, especially where the strongest theta-e
advection resides in eastern IA and northern IL. The recent HRRR
model runs generally have had cells initiating near the warm front
from east to west around PIA around 02Z. However, the most recent
(00Z) run has a lot more coverage, extending all the way from IA
through PIA to CMI to IND. Believe this is overdone based on the
latest trends and how the model is currently verifying. Still, it
will be worth watching to see if coverage trends suggest an update
is needed. So far, the forecast is on track. Either way, severe
storms are not likely tonight with weak shear this far south. The
better shear lies north of PIA where we`ve see a few strong to
severe storms already this evening.
Knutsvig
&&
.SHORT TERM... (Through Late Thursday Night)
Issued at 312 PM CDT Wed Oct 11 2023
A warm front will continue to develop out west and then move
across the CWA tonight. The first wave of precipitation has moved
north and east of the area, but additional scattered showers will
occur over the north half of the CWA tonight. Most of the area
will be dry Thur into Thur night as the CWA will be solidly in the
warm sector of the system. The next chance of precipitation will
be when the cold front comes through on Friday. As the front
moves further north of the CWA tonight into tomorrow, much warmer
temperatures are expected tomorrow and into Friday. Daytime highs
will reach into the upper 70s to near 80 tomorrow, while
overnight lows only fall into the 50s tonight, and then the upper
50s to lower 60s tomorrow night. Rainfall tonight will be the
heaviest through the short term period, with accumulations of less
than one quarter of an inch.
Auten
.LONG TERM... (Friday through Next Wednesday)
Issued at 312 PM CDT Wed Oct 11 2023
The associated cold front will approach the area late Thur night,
followed by likely and categorical pops for Friday into Friday
night. As the cold front interacts with the warm air over the
area, showers and thunderstorms will become likely during the
afternoon. Guidance solutions suggest that there will be plenty of
instability and wind shear for strong storms over the area. Heavy
rainfall could be a threat, but storms should move through
quickly enough that flash flooding should not be an issue. The
cold front should move through Friday afternoon through the
evening, which should also be good timing for strong storms. Once
the front moves through, the upper level low associated with the
system will move across northern IL/southern WI. This will keep
the CWA in a cyclonic flow pattern with continued chances of
showers through the weekend and into the beginning of next week.
There will be breaks in the precip during the night and early
morning hours. Additional precip is possible into Tuesday, but Tue
night and Wed should be dry. Temperatures over the weekend and
through Tuesday will be cooler, with highs only reaching into the
50s. Overnight lows should be in the 40s through the period.
Auten
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 642 PM CDT Wed Oct 11 2023
Showers and thunderstorms will be the primary concern tonight,
with PIA and BMI expected to be the closest to the activity as we
get deeper into the evening hours. TS is a reasonable likelihood
at PIA, but will update BMI with TS if trends prove it will be
more likely there as well. The timing looks to be generally
03-06Z, but it could linger a bit at both locations. Otherwise,
expect mid and high level clouds through the period and increasing
south winds tomorrow. Wind shear also will be a concern after 04Z
through around 15Z as the low level jet increases from the SSW.
Knutsvig
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service North Platte NE
720 PM CDT Wed Oct 11 2023
...Aviation Update...
.SYNOPSIS...
Issued at 300 PM CDT Wed Oct 11 2023
Key Messages:
- An anomalous storm system will begin to impact the area
tonight, continuing through Friday bringing strong winds, heavy
rainfall, strong to severe storms, and wintry precipitation.
- Calm, seasonable weather through weekend and early next week.
Recent GOES-16 WV and RAP 500-mb analysis showed a cut off low
pressure system centered on the Ontario/Quebec border with a
trough extending south across the northeastern CONUS. Further west
of this feature, a deep low pressure system was centered over the
state of Washington with a negatively tilted trough extending
southeast across the Great Basin. A rapidly decaying ridge was
noted across the northern Plains between the two low pressure
systems. All of these features combined has resulted in
southwesterly flow aloft across western and north central
Nebraska. At the surface, low pressure was apparent across eastern
Colorado with a weak warm front extending across northern Kansas
and a stationary front on the lee side of the Rockies, extending
into the Nebraska Panhandle. At 3P CT, temperatures ranged from
69 degrees at O`Neill to 74 degrees at Imperial.
&&
.SHORT TERM...(This evening through Friday)
Issued at 300 PM CDT Wed Oct 11 2023
The main concern in the short-term period surrounds the significant
fall system that will begin to impact the area tonight, continuing
through Friday. With multiple weather hazards expected, make sure
to continue the forecast for the most up to date information.
The focus for tonight revolves around the potential for strong to
severe storms capable of producing large hail, gusty winds, and
locally heavy rainfall for portions of central and north central
Nebraska. The aforementioned surface low will continue to deepen and
push eastward along the Nebraska/Kansas border tonight with a warm
from lifting northward across the area. As this occurs, widespread
thunderstorm development is expected along and ahead of the
frontal boundary. On the eastern periphery of the intensifying
cyclone, a 30-50kts LLJ combined with 1,000+ J/kg MUCAPE and
30-40kts 0-6km Bulk Shear will create an environment that will be
supportive of isolated to scattered strong to severe storms
capable of producing large hail and gusty winds. This round of
convection will be isolated to widely scattered due to continued
mid-level WAA creating a cap thus lowering forecaster confidence.
The greatest severe threat timing is from 9P to 3A CT across
central and north central Nebraska with general thunderstorms
expected to continue beyond 3A CT for all of western and north
central Nebraska.
As we head into Thursday afternoon, focus quickly shifts to a
potentially more impactful second round of strong to severe
thunderstorms expected to effect portions of central and north
central Nebraska. Though some discrepancies amongst model
solutions exist on exact location, the previously mentioned
surface low will push northeast into north central Nebraska
Thursday afternoon with a triple point and sharpening warm front
just ahead of the low. The southerly LLJ quickly increases to
40-50kts combined with steepening mid-level lapse rates (8+ C/km)
due to cooling aloft, modest destabilization (MLCAPE ~1,500+ J/kg)
and increasing 0-6km Bulk Shear (40kts+) will create an
environment supportive of organized thunderstorm development. The
main threat is large hail, but severe wind and a couple of
tornadoes are also possible. The greatest tornado threat lies
across portions of central and north central Nebraska where the
low-level shear will become enhanced near the triple point and
locally backed winds are expected. This is in line with similar
thinking of the previous shift and SPC`s westward expansion of the
Slight Risk of Severe Thunderstorms. This will need to be closely
monitored as we head into the near-term and details become more
fine scale. Initiation is expected by early-afternoon with the
severe threat increasing after 1P CT and the threat exiting the
forecast area around 8P CT. Make sure to take the necessary
precautions to prepare for this event by having an emergency kit
ready and multiple way to receive warning information (weather
radio, TV, cell phone, radio, etc.).
Heading into Thursday night and Friday we begin to shift focus to
strong winds across all of western and north central Nebraska and
possibly the first taste of winter across northwest Nebraska. As the
surface low begins to exit northeast out of the area Thursday night
into Friday, the SPG will tighten on the backside of the departing
system. Though wind gusts have trended down somewhat from the
inherited forecast, it will be a gusty and chilly day across
western and north central Nebraska. With high temperatures in the
40s and northerly wind gusts of 50+ mph, wind chill values will
struggle to climb out of the 30s. Combining these conditions with
continued precipitation on Friday, it will be quite the gloomy
fall day for the area. Make sure to store or secure loose items
such as holiday decoration and patio furniture before these strong
winds encompass the area late Thursday into Friday.
On the backside of the departing system, wraparound precipitation
will develop with deep forcing for ascent occurring and dynamic
cooling aloft. Model guidance continues to hint at the snow
potential for northwestern Nebraska, however, forecast confidence
continues to remain low on a complete transition to snow. Any snow
that does fall will be heavy and wet with accumulations nearing
an inch or two possible. Further east towards Highway 83, some
locations may see a rain/snow mix with no accumulations expected.
The primary concern with this period of winter weather is the
potential for reduced visibilities as the strong winds combine
with the precipitation, especially in the Friday morning commute
timeframe.
In regards to storm total precipitation amounts for this system,
we are beginning to see a more northward trend in the QPF
amounts. A swath of 1-2"+ total are expected through Friday
afternoon for areas north of Highway 2, with amounts tapering off
to the south. This is highlighted by the EFI (Extreme Forecast
Index) for QPF which is continuing to suggest increased confidence
of an anomalous event, such that the SoT (Shift of Tails) is
greater than 2 across portions of the northern Sandhills. As usual
with thunderstorms, locally higher amounts will be possible and
could lead to localized flooding.
.LONG TERM...(Friday night through Wednesday)
Issued at 300 PM CDT Wed Oct 11 2023
As the surface low moves out of the area, wrap around precipitation
remains in the area early Saturday morning, but mostly clears out by
Noon. The upper level trough moves further east as well, settling
western and north central Nebraska under upper-level convergence.
Guidance is pointing to a fairly short lived Omega block setting up
at 500-mb over the region this weekend. As the Omega block
collapses, the area remains along an upper level ridge on Monday.
There is a bit of uncertainty with the amplitude of the trough/ridge
pattern, but in general the area stays under or just to the north of
the upper-level jet stream, which will contribute to keeping
temperatures this weekend and early next week feeling more like fall
weather.
As the upper pattern continues to evolve, a shortwave trough begins
to develop over Montana on Tuesday, though there is disagreement on
timing of the set up, with the European solutions being quicker and
more aggressive compared to GEFS solutions. This is further
reinforced in cluster analysis for next Wednesday, with the more
heavily weighted European solutions progressing the shortwave over
western and north central Nebraska, indicating potential for
precipitation. Solutions more heavily influenced by the GEFS and
Canadian ensembles are a bit slower with the progression and
intensity of this shortwave, and are less optimistic on
precipitation. Either way, this will merit watching as further
ensemble runs may give a better idea on timing and potential for
precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 711 PM CDT Wed Oct 11 2023
Conditions are expected to deteriorate across all of western and
north central Nebraska later tonight and into Thursday. A strong
storm system will bring widespread IFR and MVFR ceilings and
precipitation to the area starting tonight. Southwest into
central Nebraska will be the last to see the lower ceilings
arrive, likely not until Thursday afternoon. Winds will also be
gusty, over 30 kts at times, especially across northern Nebraska.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Thursday evening through Friday evening for
NEZ004>010-022>029-035>038-056>059-069>071-094.
&&
$$
SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Richie/Viken
AVIATION...Taylor
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1023 PM EDT Wed Oct 11 2023
.SYNOPSIS...
A weak cold front will cross into the Carolinas today before
stalling. Low pressure advancing northeast from the Gulf of
Mexico combined with a cold front from the west will bring a
chance of rain to the area late Fri into Sat.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 1020 PM Wed...A cold front remains stalled across Eastern
NC while weak high pressure builds in behind it. The front will
stall to our south overnight but Gulf moisture will gradually
pool along the boundary. We`ll continue to see a gradual
increase in clouds overnight, but any precipitation risk will
remain low until pre-dawn hours Thursday when the shortwave and
attendant lift approach the region. Another inhibiting factor is
persistent low and mid-level ridging, keeping some drier air
and subsidence around before breaking down by the morning hours.
Some virga or sprinkles are possible overnight, particularly
along and south of Highway 70, but will hold off on introducing
any PoPs until around 09z.
Cloud cover will keep lows moderated despite the cooler air mass
settling in behind the front, and temperatures will likely be
close to this morning`s lows in the upper 50s to around 60
inland, mid to upper 60s along the coast.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
As of 320 PM Wed...Unsettled weather will be ongoing in the
morning as the shortwave and low continue to quickly lift into
the southwestern Atlantic. With the front stalled to our south,
stratiform rain resulting from frontal overrunning will be the
dominant precip mode. Main question remains how far north the
QPF footprint will extend, with the NAM still insistent on a dry
forecast while the bulk of hi-res guidance favors much of the
FA extending to Highway 264. Guidance spread is still higher
than average for 24 hours out, but highest confidence in
rainfall is closer to the Crystal Coast where likely PoPs were
introduced. Slight chance PoPs extend north past Highway 64.
There is bust potential on the dry side especially for locales
north of Highway 264 where a slight southward shift in the
precip field could make the difference between sprinkles and a
quarter inch of rain.
The low will race into the open Atlantic quickly, and by
tomorrow afternoon ridging and drier air will build back into the
area bringing a dry end to the day and likely breaks in the clouds.
Until then, rain and overcast conditions make for a tricky
temperature forecast, especially given the aforementioned
uncertainty in the QPF footprint. Settled for guidance consensus,
showing highs in the low to mid 70s across the south but closer to
upper 70s where some insolation is probable in the afternoon.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 220 AM Wednesday...
Friday through Tuesday...Another surface low is forecast to
move northeast out of the Gulf of Mexico and track vicinity of
the NC coast late Fri night into Sat. Meanwhile a cold front
associated with another stronger area of low pressure over the
Great Lakes will sweep a cold front through eastern NC Sat night
with a secondary cold front passing through on Sunday. The
pressure gradient will tighten between these two systems, so
expect breezier conditions over the weekend. As for rain chances
with these systems, it should be continued mainly dry Thursday
night through Friday, with better chances for rain expected
Friday night into Sat evening. Can`t rule out a few coastal
showers Sunday with the secondary cold frontal passage and again
Monday with wrap-around moisture associated with low pressure
forecast to be off the Mid-Atlantic coast. Will keep the
forecast Sunday-Monday for now but subsequent forecasts may need
to add precipitation to the forecast if a wetter trend is
observed in the models. Tue should be dry as high pressure
finally edges far enough east. Warm highs in the upper 70s are
expected Fri and Sat ahead of the cold front. Dry and cooler air
air will follow behind the front for Sunday through Tuesday as
high pressure builds over the area. Expect dry and cool
conditions with highs in the upper 60s to lower 70s Sunday and
mid to upper 60s Mon and Tue.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
SHORT TERM /through Thursday Evening/...
As of 720 PM Wed...VFR conditions will likely continue through
tomorrow despite increasing moisture into the area as an area of
low pressure moves along the Southeast coast. High based
cloud deck will slowly lower tonight with scattered showers
breaking out across the south by early tomorrow morning.
Moisture will steadily build downwards towards the surface
tomorrow morning, however a layer dry air just above the surface
should keep widespread sub-VFR conditions from developing.
Despite this, there could still be a period of time across the
southern half of the forecast area (including KEWN and KOAJ) when
rain is most widespread where ceilings drop below 3000 ft.
As low pressure moves offshore in the afternoon drier air will
quickly move in behind it and allow for skies to clear from
northwest to southeast through the afternoon.
LONG TERM /Thursday afternoon through Sunday/...
As of 220 AM Wednesday...Prevailing VFR through Fri. Rain
chances increase Fri night and Sat ahead of a complex frontal
system with a potential for brief periods of sub VFR conditions.
A return to VFR conditions are expected on Sunday as drier air
moves in from the west behind a cold front.
&&
.MARINE...
SHORT TERM /Tonight and Thursday/...
As of 330 PM Wednesday...Cold front has stalled over area waters
this afternoon, hung up roughly from the southern Pamlico Sound
to Ocracoke Inlet. Winds on the northern side of the boundary
are generally light at 5 kt or less while south of the boundary
southwesterly winds persist at around 5-10 kt. Offshore, seas
are 2-4 feet with a stubborn 12-13 second swell.
Light winds are likely to persist over the waters through
tonight as the front moves little. Biggest change to the
forecast from yesterday is in regard to low pressure, currently
over the Gulf of Mexico, forecast to traverse the waters well to
our south on Thursday afternoon and evening. The latest hi-res
guidance as trended stronger with the low and favors stronger
northeasterly winds over Onslow Bay. There is still some spread
on how strong those winds get, from the FV3 and ARW suggesting a
marginal 20-25 kt to the HRRR favoring sustained winds closer to
30 kt. This is more spread than we`d prefer to see within 24
hours, but the shift in guidance was convincing enough to hoist
a SCA for the Onslow Bay waters for Thursday afternoon. If the
HRRR proves correct, advisories may need to be extended
northward to Oregon Inlet.
Seas will remain steady state around and north of Cape Hatteras,
while to the south conditions will deteriorate quickly Thu
afternoon to 3-5 feet, and possibly an isolated 6 footer.
LONG TERM /Thursday through Sunday/...
As of 220 AM Wednesday...Conditions are forecast to remain
below advisory levels through late week then a SCA will likely
be needed for the weekend as a cold front crosses the waters.
E-NE winds 10-15 kt are expected Thu and Fri. Seas 2-3 ft Thu
become 2-4 ft Fri. NW winds around 10 kt Wed night become E
10-15 kt Thu and Fri. Winds veer to S-SW and increase to 15-25
kt Sat ahead of the cold front. Winds then shift to NW 15-25 kt
Sat night into Sun behind the cold front. The NW winds should
diminish to 10-20 kt Sun afternoon. Seas are forecast to build
to 4-7 ft Sat in response to the increasing southerly flow, then
subside to 3-5 ft Sun afternoon in the diminishing offshore
flow.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...Small Craft Advisory from 11 AM to 8 PM EDT Thursday for
AMZ158.
&&
$$
SYNOPSIS...MHX
NEAR TERM...SGK/MS
SHORT TERM...MS
LONG TERM...JME
AVIATION...JME/SGK/MS
MARINE...JME/MS
Area Forecast Discussion
National Weather Service Raleigh NC
945 PM EDT Wed Oct 11 2023
.SYNOPSIS...
An area of low pressure will move across the Florida Peninsula from
the Gulf of Mexico to the Atlantic Ocean on Thursday. A second low
pressure system will move from the central Plains offshore the mid-
Atlantic states over the weekend.
&&
.NEAR TERM /TONIGHT/...
As of 945 PM Wednesday...
Cloudy skies continue to be observed across NC this evening. Light
rain has advanced into central and portions of northern SC. However,
rainfall amounts have been barely measurable as far north as
Columbia and Florence. The rain shield is expected to finally reach
into southern and southeastern NC during the early morning hours (2-
6 am). The latest HRRR suggests that measurable rain may extend as
far north and west as Albemarle, Sanford, and Raleigh by daybreak.
Even so, this is about as far northwest as the light rain would
extend before being shunted off to the east rather quickly on
Thursday. Thus, no headline changes to the forecast. Lows generally
in the 50s expected.
Previous discussion issued at 200 PM Wednesday...
Overcast skies have been observed through the day, and this will
continue into the overnight hours. Low pressure along the Gulf of
Mexico coastline will move east towards Florida through daybreak.
The ongoing dilemma with this forecast has been how far to the north
the rain shield will extend and there is good consensus that the
northern edge will be somewhere in our forecast area. Although
recent model runs have tried to push the rainfall a little farther
to the north, model soundings from multiple models at Fayetteville
show very little saturation in the lowest mile of the atmosphere,
which should diminish the odds for measurable precipitation. While
slight chance pops were expanded slightly to the north, the current
forecast still does not have any chance of precipitation north of US-
64 in central North Carolina. Bumped up overnight lows by a couple
of degrees, ranging from 52 to 60.
&&
.SHORT TERM /Thursday and Thursday night/...
As of 315 PM Wednesday...
A shortwave and low pressure will race east off the SC coast along a
stalled frontal zone Thursday morning, with light rain mostly
focused over SC and far SE NC. However, given the strength of the
upper jet and lift, very light rain and sprinkles may briefly reach
north into the Piedmont, but that should all end after sunrise as
moisture cross-sections, which never really saturate below 750mb,
show rapid clearing from NW to SE by midday. The aforementioned low
will be followed by weak surface high pressure breaking off from the
parent high over central Canada and settling over NC/VA. With much
more sun and no airmass change, temps should be as much as 4-8
degrees warmer than today, especially in the Piedmont. Highs in the
mid and upper 70s. Clear skies and weak pressure gradient Thursday
night, so trending with cooler guidance in outlying areas - upper
40s to mid 50s.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 225 PM Wednesday...
While no major hazards are in sight through this period, we are
likely to see a few bouts of disturbed weather, namely Fri night
through Sat evening, late Sun through Sun night, and on Tue. Above
normal temperatures Fri/Sat will yield to falling heights over much
of eastern NOAM, resulting in below normal readings early to mid
next week.
Fri-Sat night: This time frame begins with NC beneath flat ridging
over the Southeast coast extending into MI, bracketed by closed lows
over the Midwest and the Maine coast. This mid level flow over NC
will flatten further and accelerate as the Midwest low pushes
eastward to near Chicago through Sat. This low will then fill
through Sat night as it shears E across PA/NJ, with below normal
heights extending westward to another shortwave trough over the mid
Miss Valley. At the surface, the weak frontal zone to our south will
push north as a warm front early Fri, placing NC within the warm
sector. Much of Fri should be dry, but with increasing and
thickening mid clouds. Rain chances will rise Fri evening/night,
particularly over the western CWA where moist isentropic upglide
will deepen and strengthen through the 290K-310K depth, atop
retreating weak surface high pressure and associated with 850 mb
warm front passage. This upglide will remain deep and expand over
the rest of the CWA Sat, finally exiting to our NE Sat night with
decreasing rain chances as the surface-850 mb front/trough shifts to
our E. Model agreement is good, with over 70% of LREF members
showing measurable rain over central NC, so will go with good chance
to likely pops during this period. Any rain should be mostly light,
however, as there is little saturation up into the mixed phase
region, allowing for greater hydrometeor size. Temps will average
above normal, albeit with a lower diurnal range owing to the clouds
and precip.
Sun-Wed: The precip lull should last through much of Sun, as the
primary surface front pushes offshore and mid level flow flattens in
between mid level shortwave troughs. The wave diving through the mid
Miss Valley late Sat will swing through the Carolinas late Sun,
bringing a reinforcing secondary front ESE through the area. The low
level flow will be largely downslope-directed and as such won`t be
able to tap into moisture sources, although the potential for a
period of strong UVM as the wave passes along with a period of more
northerly low level flow should still support a chance of rain late
Sun through Sun night. An expansive surface high will build from
central Canada down through the central and eastern CONUS, resulting
in dry and cool weather Mon. Then, yet another upper low will deepen
over the central and southern Appalachians, with the potential for a
period of ascent via DPVA along with steepening lapse rates, so will
have a mention of isolated showers as this feature passes by.
Sinking air through the column and fair weather should return Wed,
with the core of surface high pressure drawing closer as it builds
in from the NW amidst confluent mid-upper flow. Slightly below
normal temps Sun should drop to about two categories below normal
for Mon-Wed. -GIH
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 640 PM Wednesday...
There is high confidence in VFR through most of the TAF period. A
southern stream area of low pressure will warrant the chance of
brief low-end VFR to MVFR conditions in light rain at FAY between 10
and 14Z Thu. The latest guidance continues to show some light rain
reaching as far north as the Sandhills. Probabilities for MVFR at
FAY remain low at around 30-percent. However, the latest HRRR/NAM-
NEST/GFS suggest a period of MVFR VIS in the aforementioned time
frame. Given this trend, introduced a brief period of MVFR at FAY
but still expect VFR to prevail the majority of the time. Otherwise,
cloud cover around 15-25 kft at the other terminals will slowly give
way to afternoon sunshine, with SSW winds become ENE around 5 kt.
Outlook: Dry VFR weather should dominate Thu afternoon through
Friday evening before an approaching front brings scattered showers
and the potential for restrictions late Friday night through
Saturday evening. Dry VFR conditions should return for Sunday and
Monday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Green
NEAR TERM...Badgett/Green
SHORT TERM...BLS
LONG TERM...Hartfield
AVIATION...Kren/Green
Area Forecast Discussion
National Weather Service Salt Lake City UT
353 PM MDT Wed Oct 11 2023
.SYNOPSIS...A cold Pacific system will bring valley rain and
mountain snow to northern and central Utah through Thursday. High
pressure will bring a warming and drying trend this weekend.
Another system is possible Tuesday into Wednesday.
&&
.SHORT TERM (Through 12z/6AM Friday)...An active short-term
period continues, with valley rain, mountain snow, lake-effect
showers, and the first freezes for some locations all in store
before Friday morning.
Recent water vapor satellite imagery shows a broad longwave
trough continuing to push south and eastward across Utah and
southwest Wyoming. Dynamics associated with a NNW-SSE oriented jet
streak to our west combined with shortwave energy in the mid-
levels will promote continued scattered showers across central and
especially northern Utah through the evening and into the
overnight hours. A heavier round of showers currently pushing
eastward across the Wasatch has even produced isolated
thunderstorms and locally gusty winds.
At the surface, the cold front is currently draped across roughly
Cedar City to Price to Duchesne and is expected to slowly nudge
southeastward, bringing northwest flow and some of the coldest
temperatures we`ve seen this season so far. Localized downsloping
may bring some breezy conditions to Castle Country, with locations
up against higher terrain seeing gusts to 25-35 mph overnight.
As for precipitation, there are two mesoscale factors at play
overnight combined with favorable synoptic dynamics. The first is
orographic enhancement in northwest flow-favored areas such as the
Upper Cottonwoods. The low levels are likely to remain quite
moist through Thursday, thus these orographic showers may continue
into Thursday evening, despite low-level stability increasing
through the day on Thursday. The second, which has much more
uncertainty, is any lake-effect precipitation development.
There are many ingredients for lake-effect development overnight,
with warm lake temperatures, cold 700-mb temperatures, and
plentiful low-level moisture. With the GSL temperature around
+16C and 700-mb temperatures dropping to an ensemble mean of -5C
overnight, this is more than enough of a 700-mb to lake
temperature difference to get lake-effect going. The most likely
timing for lake-effect is roughly between 10PM-8AM, though the
exact location is still uncertain. CAMs have trended more towards
the western Salt Lake Valley, eastern Tooele Valley, and just
southeast of Utah Lake. Any lake-effect showers will ultimately
impact precipitation totals and precipitation type, as rate-driven
cooling could make snow levels plummet locally. More on this
next. The HRRR is often more bullish in terms of banded
development, as is the case today. Development of a strong band
isn`t out of the question, however, with a strong lake-land
temperature difference and 700-mb winds approaching 30kts
overnight. Other CAMs are a bit less organized in nature.
Outside of any lake-effect showers, snow levels will drop to
roughly 6300-7000` overnight, with snow in the mountains and rain
in most valleys in northern/central Utah. Within any lake-effect
showers, and especially within stronger showers, this could drop
snow levels significantly. Depending on where the showers set up,
this means areas near Tooele could see sleet or even 1-2 inches of
snow under a persistent band in the early morning hours.
During the day on Thursday, valley showers will begin to subside
during mid day as mountain showers continue in orographically-
enhanced areas. Subsidence will begin to take over Thursday night.
Storm totals across the northern Utah mountains are around 2-8
inches of snow, with locally higher amounts up to 18 inches in the
Upper Cottonwoods. As a result, a Winter Weather Advisory
continues for the Wasatch and Western Uinta Mountains.
With such a cold air mass, Freeze Warnings are in effect for many
valleys across Utah, excluding and central and northern Wasatch
Front, with minimum temperatures below 32F expected Friday
morning ahead of a warming trend.
.LONG TERM (After 12Z/6AM Friday)...Long term period begins with the
midweek trough continuing its eastward departure and a weak and
transient ridge building in behind it. Light winds and clearing
skies overnight will result in cool temperatures to start off
Friday, with many valleys (excluding the Wasatch Front) seeing
temperatures near to below freezing. While the increasing influence
of ridging will help initiate a warmup, will only see afternoon high
temperatures Friday in the upper 50s to low 60s across most of the
Wasatch Front, and mid 70s across lower Washington County, which
equates to roughly around 5 to 10 degrees below climatological
normal.
Friday night into early Saturday the ridge flattens and begins to
shift east in response to a weak grazing shortwave pushing in from
the PacNW. While precipitation isn`t expected, this will allow for
an increase in upper level moisture and a corresponding increase in
mostly high level clouds. Most guidance continues to support a south
to north clearing trend through the morning hours Saturday, which
bodes well for those planning on viewing the annular eclipse from
southern Utah... Though the exact timing of the aforementioned
clearing will certainly be something to watch as we get closer to
the event. While at least some clearing is also currently expected
across northern Utah and southwest Wyoming, general consensus
continues to support a mix of sun and clouds. Otherwise, despite the
weak grazing shortwave, will still see afternoon highs increase
several degrees to near seasonal normal levels.
Sunday into the start of the work week will see increasing ridging
through the SW CONUS, resulting in a continuation of dry conditions
and temperatures pushing back above normal for mid October. Guidance
begins to diverge a bit moving further into the week in regards to
another trough pushing ashore across the PacNW. While most guidance
shows a bit of consensus in at least some weakening of the ridge, a
subset of around 10% of ensemble members show a more potent trough
trying to push in, and around 30% of ensemble members show a weaker
version of this feature encroaching. In both cases this seems to be
weighted mostly towards Canadian ENS members, and if it were to pan
out, would result in wetter and colder conditions. As it stands
though, opted to stick with NBM guidance which just brings some
lower end precipitation chances back to the northern third of the
forecast region, in addition to a slight cooldown.
&&
.AVIATION...KSLC...Primarily VFR conditions throughout the period
with intermittent MVFR as a cold front ushers in showers and lowered
CIGs. A lull in showery activity this evening will be followed by
lake enhanced bands of showers overnight after 06Z into tomorrow
morning. These bands will be isolated in nature with only ~30%
chance of impacting the terminal as the best chances will stay west.
CIGs will be below 6kft overnight, creating mountain obscuration.
Winds will remain northerly.
.REST OF UTAH AND SOUTHWEST WYOMING...For southern Utah, mainly VFR
conditions will prevail throughout the period. Conditions will
remain mostly dry with isolated showers (~30% chance) as far south
as Cedar City and Bryce Canyon between 00-06Z that could briefly
create MVFR/IFR conditions. For northern Utah/SW Wyoming, scattered
showers this afternoon with lowered CIGs <6kft will create brief
MVFR/IFR conditions as well as mountain obscuration through this
evening before a transition to northwest flow isolated shower bands
for northeast Utah/SW Wyoming lasting through mid morning. Snow
levels will be ~6500 ft. Winds will remain northerly.
&&
.FIRE WEATHER...Widespread rain showers with embedded thunderstorms
are noted across Utah this afternoon with mountain snow showers. Wetting
rains are forecast across northern Utah tonight and into Thursday. Breezy
north to northwest winds are expected in eastern and southern Utah this
evening and into Thursday evening with gusts in excess of 35 mph above
6,000 ft while gusts in excess of 50 mph are forecast in the Central
Mountains. High pressure will gradually build in late week and into the
weekend.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Freeze Warning from 9 PM this evening to 9 AM MDT Friday for
UTZ102-106-114>116-118>120-122-129.
Winter Weather Advisory until noon MDT Thursday for UTZ110>112.
WY...None.
&&
$$
SHORT TERM...Cunningham
LONG TERM...Warthen
AVIATION...Mahan
FIRE WEATHER...NDeSmet
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
830 PM EDT Wed Oct 11 2023
...New UPDATE, AVIATION...
.UPDATE...
Issued at 830 PM EDT Wed Oct 11 2023
Scattered showers and a few thunderstorms continue to develop and
move north across the area this evening. As the night progresses
we`ll see convective coverage increase across the Nature Coast
south into the central Florida peninsula as upper level energy and
instability move into the region, while convection remains
scattered across southwest Florida. This pattern will persist
through Thursday morning, then we`ll see the main area of
convection begin to shift south during the afternoon as the
shortwave energy moves by to the north. Overall the current
forecast looks ok, but may adjust PoPs some to reflect current
thinking.
&&
.AVIATION...
(00Z TAFS)
Issued at 830 PM EDT Wed Oct 11 2023
Scattered convection early tonight will become more numerous after
midnight through early afternoon Thursday around the Tampa Bay
TAF sites of TPA, PIE, LAL, and SRQ. Convection should remain
mainly scattered across southwest Florida. MVFR/local IFR
conditions are expected within the convection and some areas of
MVFR ceilings will be possible later tonight into Thursday morning
the moist airmass across the area. Otherwise mainly VFR
conditions are expected. Southeast to south winds will increase
overnight to 10 to 15 knots with some gusts to around 25 knots and
then increase to 15 to 20 knots with gusts to around 30 knots
mid- morning Thursday through the afternoon hours. Winds will be
erratic within any convection and could gust to 35 knots later
tonight and Thursday.
&&
.DISCUSSION...
Issued at 308 PM EDT Wed Oct 11 2023
We will be looking at some unsettled weather for the next few days
with possible severe weather overnight and early tomorrow
morning. First lets talk about what is setting all this up. We
will have a low pressure system pushing through Florida just north
of our area. This will increase our moisture and help to bring a
few rounds of shower and storms across the area. Thanks to the
moisture and heat return we will see a more typically pop up
showers and storms across the area this evening.
Overnight we will see the low pressure itself passing north of the
area through the Panhandle and southern Georgia. This will bring
another round of showers and storms and its this round we are
concerned about when it come to severe weather. Our concern is high
winds and the possibility for tornadoes. Looking at sample forecast
soundings along the coast for the HRRR we are seeing backing winds
at the surface and higher values for 0-1km SRH which in turn is
giving us high STP values overnight between 06z and 12z. However we
also have PWs at 2.5 and CAPE values not to impressive. So we
know storms will be spinning but will they be able to reach the
ground.
After that the front that is associated with the low pressure system
will stall over the area. Severe weather risk will be much lower but
weather will continue to be unsettled through the rest of the week
with scattered showers and storms through the afternoon and evening
both Thursday and Friday.
Next weekend will be much like last weekend. Saturday will be warm
and humid with a cold front pushing through. A few showers will be
possible but chances will be lower compared to the end of the week.
For Sunday cooler and drier air will start to filter in bringing in
pleasant weather once again.
Early next week we will see dry but below average temperatures. We
could see widespread low 60`s and upper 50`s in the morning with
highs staying in the 70`s.
&&
.MARINE...
Issued at 308 PM EDT Wed Oct 11 2023
A strong south to southwest flow will cause hazardous marine
conditions over the Gulf and coastal waters tonight into tomorrow.
Scattered to numerous showers and thunderstorms will impact waters
now through Thursday, some storms may be severe with damaging winds
and possible waterspouts.
&&
.FIRE WEATHER...
Issued at 308 PM EDT Wed Oct 11 2023
No fire weather concerns through the weekend as RH values remain
well above criteria. Strong to severe thunderstorms expected through
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 79 87 80 88 / 80 80 30 50
FMY 80 90 80 90 / 80 50 20 40
GIF 76 88 77 89 / 90 80 40 70
SRQ 78 88 79 89 / 80 70 30 50
BKV 74 87 76 89 / 80 80 30 60
SPG 78 87 80 86 / 80 70 30 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk from 2 AM EDT Thursday through Thursday
evening for Coastal Charlotte-Coastal Hillsborough-Coastal
Lee-Coastal Manatee-Coastal Sarasota-Pinellas.
High Surf Advisory from 2 AM to 8 PM EDT Thursday for Coastal
Hillsborough-Coastal Manatee-Coastal Sarasota-Pinellas.
Coastal Flood Advisory from 10 AM to 5 PM EDT Thursday for
Coastal Citrus-Coastal Hernando-Coastal Hillsborough-
Coastal Levy-Coastal Pasco-Pinellas.
Gulf waters...Small Craft Advisory from 2 AM to 2 PM EDT Thursday for
Charlotte Harbor and Pine Island Sound-Coastal waters from
Bonita Beach to Englewood FL out 20 NM-Coastal waters from
Englewood to Tarpon Springs FL out 20 NM-Tampa Bay waters-
Waters from Bonita Beach to Englewood FL out 20 to 60 NM-
Waters from Englewood to Tarpon Springs FL out 20 to 60 NM.
Small Craft Advisory until 2 PM EDT Thursday for Coastal waters
from Tarpon Springs to Suwannee River FL out 20 NM-Waters
from Tarpon Springs to Suwannee River FL out 20 to 60 NM.
&&
$$
UPDATE/AVIATION/MARINE/FIRE WEATHER...Close
DECISION SUPPORT...Giarratana
UPPER AIR/CLIMATE...Hurt