Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/25/23
Area Forecast Discussion
National Weather Service Charleston SC
1006 PM EDT Tue Oct 24 2023
.SYNOPSIS...
Dry high pressure will prevail across the region this week and
possibly into early next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Since early this evening, IR satellite has detected a expanding
area of clouds across the near shore waters of GA and SC,
spreading inland across coastal GA and SC. In addition, KCLX
detected at least isolated weak showers across the outer GA
waters. Chaff was detected off the coast of SC, south of the CHS
Harbor. The latest runs of the HRRR and HREF indicate that
shower activity may continue to develop within a coastal trough
through the rest of this evening, into the late night hours. The
updated forecast will feature higher PoPs and cloud cover over
the coastal waters and coastal counties through late tonight.
Low temperatures are forecast to range from the low 50s inland
to around 60 along coast.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Ridging extending into the southeastern states from the Gulf of
Mexico will prevail aloft through the end of the week. At the
surface high pressure centered off the Mid-Atlantic coast will build
into the region from the north. This pattern will yield dry and
sunny conditions as well as a warming trend across the forecast area.
Temperatures Wednesday will be a few degrees above normal, with
highs in the upper 70s. Highs are expected to warm a few degrees
each day, with around 80 on Thursday and low 80s Friday. Overnight
lows will also follow the above normal trend, with mid to upper 50s
far inland and low to mid 60s along the coastline.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Not much change in the overall pattern is expected through the
weekend and into early next week. High pressure at the surface will
continue to expand into the forecast area from the Mid-Atlantic,
while ridging prevails aloft. A dry forecast has been maintained
through the period. Temperatures will remain several degrees above
normal, owing to the building high pressure. High temperatures are
forecast to be in the low to mid 80s with overnight lows in the mid
to upper 50s far inland and low to mid 60s near the coastline.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR expected through 0Z Thursday. Stratocu between 4-5 kft may
move in off the Atlantic late tonight and then slightly greater
low-level moisture should support Cu development during the day
Wednesday. Light northeast winds tonight are forecast to veer
from the east by Wednesday afternoon.
Extended Aviation Outlook: Prevailing VFR.
&&
.MARINE...
A persistent NE gradient will continue through tonight, though
wind speeds could decrease by 3-5 kt late tonight as the surface
high sinks south. The extended NE fetch is slowly building seas,
and some 6 footers are expected to move into the offshore GA
waters this evening. We therefore have a Small Craft Advisory
beginning at 8pm for these waters.
Wednesday through Monday: High pressure will prevail over the marine
zones, with a weak coastal trough possibly developing over the far
southern zones. This weak troughing could produce a few showers over
the offshore GA waters. Otherwise, dry conditions are expected with
enhanced wind speeds on Wednesday as the pressure gradient pinches
due to the building high pressure. Northeasterly winds on Wednesday
of 10 to 15 knots with gusts around 20 knots will ease on Thursday
and into the weekend, only around 10 knots. While these wind speeds
will remain below Small Craft Advisory criteria, the long
northeasterly fetch will yield wave heights of 5 to 6 ft in the 20-
60 nm offshore GA waters. A Small Craft Advisory remains in effect
for these waters.
Rip Currents: Northeasterly winds coupled with a 2 ft, 10-11 second
swell, and increasing influences from the approaching lunar perigee
will support a moderate risk of rip currents for all area beaches
Wednesday and Thursday.
&&
.TIDES/COASTAL FLOODING...
Still concerned that increasing astronomical tides and northeast low
level winds will create elevated tide levels during the late
afternoon/early evening high tides later this week. We`ll be
very close to 7.0 ft with the evening high tides Wednesday and
Thursday, then more likely with the evening tides Friday through
the weekend. Coastal Flood Advisories may eventually be needed.
For the remainder of the coast, we are not expecting tides to
reach Coastal Flood Advisory levels, but tides will still be
elevated.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 11 AM EDT Friday for AMZ374.
&&
$$
NEAR TERM...NED
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...NED
MARINE...CPM/JRL
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
841 PM CDT Tue Oct 24 2023
...Short Term Update...
.UPDATE...
Issued at 841 PM CDT Tue Oct 24 2023
-- VARIOUS NOTES REGARDING RECENT FORECAST TWEAKS MADE TO THE
FIRST 12-24 HOURS (through Wed daytime):
Although we are not expecting any truly "high impact" weather
during these next 24 hours, and only we typically don`t "mess
with" the forecast beyond the first 12 hours on evening/swing
shifts, was compelled enough to make a few adjustments this
evening to the overnight-Wednesday daytime forecast that seemed
worth addressing here:
- Precip chances (PoPs):
Made some modest adjustments to PoPs through these next 24 hours,
largely following trends of latest models guidance (including
higher-res HRRR/NAMNest). In brief: kept PoPs very low pre-
midnight (20-30%) as most areas will likely stay dry. However,
starting late overnight and especially into the daytime hours
Wednesday, nudged PoPs up to as high as 30-50% most areas, as the
arrival of various low-amplitude disturbances embedded within
southwesterly flow aloft, along with a modest increase in elevated
instability/CAPE values (greater coverage of generally 500-1000
J/kg mainly in the 850-700 millibar layer) should foster a greater
coverage of at least isolated/scattered showers and storms
compared to today (during which most all areas either remained dry
or only had very light drizzle). As noted by day shift forecaster
below, a few strong to MAYBE even marginally-severe storms cannot
be ruled out (mainly with a hail threat) cannot be ruled out, but
the vast majority of any storms will likely be fairly weak.
- Addition of "patchy drizzle" to the official forecast:
Considering that an extensive low cloud deck will continue
overtaking most/all of our coverage area (CWA) through the night
and into Wednesday behind the southward-sinking surface front,
along with the fact that some northern areas (such as Ord) already
observed patchy/light drizzle earlier this afternoon, decided to
re-introduce an official mention of "patchy drizzle" to all areas
where cloud ceilings are forecast to be 1,000 ft. AGL or lower
(typically heights most conducive for drizzle development). In
other words, even if "true" showers/thunderstorms are not
occurring, pesky light drizzle could certainly be a possibility on
at least a patchy/intermittent basis.
- Addition of "patchy fog" to mainly our far southern zones for
Wed AM:
Although as is typical of many possible fog scenarios, confidence
is not overly-high. However, various model visibility progs
(including HRRR/SREF) seem to be at least somewhat suggestive of
at least light/patchy fog development late tonight into Wed AM,
particularly in our extreme southern CWA (particularly
Rooks/Mitchell/Osborne counties) in the vicinity of where the
surface front will likely stall-out. As a result, have introduced
basic "patchy fog" to the overnight-Wed AM forecast for mainly
these far southern areas (although probably cannot rule it out
elsewhere as well).
- High temps adjusted downward for Wednesday (and maybe/probably
not enough?):
With various modes/guidance keeping at least the vast majority of
our CWA pretty "socked in" under extensive low clouds through
Wednesday daytime, along with the insistence of various sets of
latest guidance (including HRRR/RAP) in a cooler day, have already
shaved 3-4 degrees off of the Wed high temp forecast versus this
afternoon`s main "forecast package". With these adjustments, we
are now aiming for only upper 50s at best far north/west- central
(Ord/Lexington areas), mainly low-mid 60s central (Tri Cities
area), and any low-mid 70s possible mainly within our south-
southeast 1/3 (KS zones along with Hebron/Nelson area). Further
downward adjustments could very well be warranted, but will defer
to upcoming mid/overnight shift to go there.
&&
.DISCUSSION...(This evening through Tuesday)
Issued at 315 PM CDT Tue Oct 24 2023
Key Messages:
* Mostly cloudy skies are expected to linger across the local area
for the next several days as a weak frontal boundary meanders
across the region.
* A few showers and some isolated thunderstorms are possible
overnight tonight and off and on at times through Thursday
evening. A few strong to marginally severe thunderstorms will be
possible mainly from the early Wednesday morning through
evening hours Wednesday.
* A cold front will push across the local area late Thursday
night, with gusty northerly winds and noticably cooler
temperatures to end the work week.
* A second shot of cold air accompanied by an upper level trough
will bring the coldest air so far of the season for the weekend,
along with a chance for some wintry precipitation as early as
Saturday morning and lingering possibly into the morning hours
Sunday.
Mostly cloudy skies have persisted across the local area today,
with a weak cold front stalled out across our northern counties
resulting in quite a temperature gradient extending from roughly
Ord down south towards the Hastings area. An upper level
disturbance coming out of the southwest will then lift northeast
towards the local area by around daybreak Wednesday, with the cold
front lifting further north through the morning hours. With
nearly a thousand joules of elevated CAPE to work with, this
disturbance could be enough to spark some isolated strong to
marginally severe convection, with marginally severe hail being
the main concern, and wind a slightly lesser concern. The HRRR has
been consistently hinting at an area of convection during the
morning hours Wednesday, and while the exact location is a bit
uncertain, do expect some convection around tomorrow starting
during the morning hours. Ahead of this disturbance, have small
pops in the forecast during the evening through overnight hours,
but confidence in much in any precipitation is fairly low lacking
significant forcing overnight. If some showers or storms do
materialize later this evening or early during the overnight
hours, they will be very hit or miss with most areas likely
staying dry.
After the initial disturbance expected Wednesday morning, a
couple of additional disturbances will lift out of the southwest
keeping the chance for unsettled weather in the forecast through
late Thursday evening, before a cold front eventually shifts south
across the local area on Friday, bringing and end to the precip
chances in its wake along with noticably cooler/breezy
conditions...resulting in a blustery finish to the work week.
This will just be a pre-cursor to even colder weather, however,
as even colder air works its way across the region Saturday as
some upper level shortwaves moving out of the Rockies track across
the local area. With very cold air likely already in place both
at the surface an aloft, expect the possibility for some wintry
precipitation across the area beginning Saturday morning and
continuing through Sunday morning. Still don`t have a ton of
confidence on amounts with this system, but light snowfall
accumulations do look possible. There also is a small chance for
some mixed precipitation, and while the NBM continued this mention
in the official forecast, soundings look to be more
representative of only some light sleet or snow with the latest
runs...but still plenty of time to hammer that out.
Of more confidence is the likely end to the growing season for the
entire forecast are Saturday morning as low temperatures dip into
the lower 20s across our north to upper 20s and lower 30s across
north central Kansas. With much of this area still susceptible to
freezing...expect some sort of freeze headline to eventually be
needed this weekend. This cold air will then linger for several
days into the first part of next week, with the upper level flow
eventually becoming more westerly late in the period resulting in
a modest warming for the middle to latter part of next week.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 727 PM CDT Tue Oct 24 2023
-- UP FRONT NOTE REGARDING KEAR TAF/WEATHER OBSERVATIONS:
An "AMD NOT SKED" (amendment not scheduled) has been appended to
the KEAR TAF given a failure of the automated weather observations
system since Tuesday afternoon. A NOTAM is currently in effect
regarding this issue, and KEAR TAF will likely remain in an AMD
NOT SKED status until automated observations resume.
- General overview (including wind details):
Confidence is high in sub-VFR conditions through at least the vast
majority of the (if not the entire) period, particularly with
regard to ceilings, although at least brief sub-VFR visibility
probably cannot be completely ruled out either. Precipitation-
wise, while the majority of the period will likely remain dry,
spotty/brief showers and perhaps a passing thunderstorm cannot be
ruled out at times, and there is also the possibility for some
intermittent light drizzle. Winds should not be a major issue,
with sustained speeds throughout mainly at-or-below 10KT, with
direction prevailing northerly through the first 12 hours
(overnight), and then more easterly during the latter 12 hours
(Wednesday daytime).
- Ceiling/visibility details:
High confidence in sub-VFR ceiling through nearly the entire
period. While MVFR will likely prevail through at least these
first 6 hours or so this evening, there will increasing
probability for IFR late tonight into Wednesday morning, before
eventually improving back to MVFR Wednesday afternoon. Although
not currently indicated as a prevailing group, at least a brief
period of LIFR ceiling cannot be ruled out Wednesday morning,
particularly at KEAR. As for visibility, odds favor VFR at least
the vast majority of the time. However, at least brief MVFR/IFR is
possible during any possible passing showers/thunderstorms, and
also if any periods of steadier drizzle happen to develop mainly
late tonight into Wednesday morning.
- Precipitation details:
This is one of those periods where although odds favor it
remaining dry the majority of the time, there is just enough
forcing aloft (along with modest elevated instability) that
periodic development of isolated/scattered showers and mainly weak
thunderstorms cannot be ruled out. As a result, have a generic
mention of "vicinity shower" (VCSH) going through the majority of
the period, but at least for now confined any "vicinity thunder"
(VCTS) to the 12-18Z time frame when higher-res models suggest any
thunder would be most likely. In addition, have introduced a
mention of -DZ (light drizzle) to the 06-18Z time frame, as even
if there are no active showers/storms, the low levels appear
sufficiently saturated to support at least occasional/patchy
drizzle.
&&
.CLIMATE...
Issued at 840 PM CDT Mon Oct 23 2023
-- DECREASING CHANCES FOR NEAR-RECORD WARM LOW TEMPERATURES
TUESDAY/WEDNESDAY AT HASTINGS AIRPORT:
Thanks to a slightly-more aggressive invasion of cooler air this
evening and overnight versus earlier forecasts, it is looking
increasingly likely that existing Oct. 24th-25th records for
warmest low temperature will remain "safe"/intact at Hastings
airport (these records were already deemed safe/intact for Grand
island airport, mainly due to existing records being several
degrees warmer). Details for both sites follow, but this will
likely be the last update to this .CLIMATE section now that warm
low temperature records appear out of reach at Hastings.
-- Hastings airport (HSI)...existing records now likely SAFE:
Latest forecast calendar day low temp versus existing records:
Oct. 24 (Tues)...forecast 52 near midnight...record 59 (1963/1956)
Oct. 25 (Wed.)...forecast 51 early AM........record 56 (2000)
-- Grand Island (GRI)...existing records clearly SAFE:
Latest forecast calendar day low temp versus existing records:
Oct. 24 (Tues)...forecast 50 near midnight...record 64 (1899)
Oct. 25 (Wed.)...forecast 50 early AM........record 60 (2000)
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...Pfannkuch
DISCUSSION...Rossi
AVIATION...Pfannkuch
CLIMATE...Pfannkuch
As mentioned in previous forecast discussions, a surface high will
build into the region on Friday and remove our chances of
precipitation. Cold air advection will continue into the afternoon
which will keep our temperatures cooler than normal. High
temperatures will only warm into the mid 40s to mid 50s, while
overnight temperatures will cool into the mid 20s and low 30s.
The upper-level flow will return to the southwest Friday night and
the jet stream slowly moving southeast throughout the rest of the
period. This will allow colder temperatures to move in through the
weekend. By Saturday morning the jet stream will begin moving over
the region and will cause enough of a disturbance for some slight
chance PoPs. PoPs will increase in the evening hours with the best
chances for precipitation being locations northeast of a line from
Stratton, NE to Gove, KS. These chances will begin falling around 6Z
Sunday. Due to the cold temperatures, any precipitation that does
fall will have a chance at being a wintry mix, including rain or
snow. The possibility of snow is greatest in the northern portions
of the CWA and spreading south as the event progresses. There is a
chance that due to a fairly shallow saturated layer Saturday
evening, before heavier precipitation picks up, drizzle could occur.
This could be an issue depending on surface and near surface
temperatures; if below freezing for long enough, elevated surfaces
will have a shot at accumulating a little bit of ice. There is low
confidence that ice or snow will accumulate and exact determination
of P-Types, including location and timing, this far out would likely
not be very accurate. This general setup will continue until Sunday
afternoon, ending earlier than previously expected.
Sunday morning wind chills are expected to be in the single digits
across most of the area. Thanks to the precipitation and ongoing
cold air advection, Sunday may experience a midnight high
temperature, but confidence is lowering. Either way, Sunday will be
cold with maximum temperatures in the 30s. As the remaining moisture
moves out of the area, the clouds will clear out and allow
temperatures to cool efficiently. Overnight temperatures Sunday will
drop into the mid teens and low 20s across the region.
Monday morning wind chills are expected to be slightly warmer than
Sunday`s with upper single digits and low teens expected in the CWA.
Northwesterly flow aloft is looking to make a return Monday.
Combined with lower level increased pressure, this should keep the
sky clear. This will allow Monday and Tuesday to see a warming trend
and very little chance of precipitation. High temperatures will
climb to the mid and upper 40s both days, with some locations
potentially seeing low 50s on Tuesday. Monday night will still be
cold with lows in the upper teens and lower 20s. Combined with
northwesterly winds, wind chills Tuesday morning will still be in
the upper single digits and lower teens.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 506 PM MDT Tue Oct 24 2023
Difficult aviation forecast for this TAF period as there is decent
agreement with guidance for fog and stratus developing/continuing
across the region.
For KGLD, RAP forecast soundings show ample low level saturation
at 03Z so opted to start stratus development a little earlier than
anticipated. LIFR conditions are currently forecast to develop by
09Z and last through mid morning, before slowly improving albeit
low ceilings look to linger through the majority of the day.
KMCK, a bit more dry air at the surface should delay stratus
development at least through 05Z; obs to the northeast of the
terminal have been in MVFR to IFR ceilings for the majority of
the day so will closely monitor in case it sets in earlier. IFR
conditions will develop overnight and last through the early
afternoon; periods of LIFR are possible but confidence wasn`t
there for exact timing to introduce into the TAF.
Showers and storms may increase in coverage mainly south and east
of the terminals, a few hit or miss showers or storms may be near
the terminals around sunrise but confidence in impacting the
terminal wasn`t high enough to introduce at this time so opted to
focus on the fog and stratus potential.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...Trigg
SHORT TERM...JRM
LONG TERM...CA
AVIATION...Trigg
Area Forecast Discussion
National Weather Service Norman OK
1051 PM CDT Tue Oct 24 2023
...New AVIATION...
.SHORT TERM...
(This evening through Wednesday)
Issued at 252 PM CDT Tue Oct 24 2023
We are nearing the halfway point of our tropically-influenced fall
rain event. Radar and gauge observations show that within the the
region bounded by Seymour/Ardmore/Enid/Quanah, about 1-2 inches of
rain fell overnight and this morning. Round 1 will wrap up as a band
of low-topped convection translates east-northeast across the
southern half of Oklahoma, propelled by the ejection of the lead
wave. Per RAP soundings, some instability is present, so the threat
for some lightning strikes and perhaps gusty winds will be possible
this afternoon.
As the lead wave departs, a lull in widespread precipitation is
expected overnight, though some showers remain possible across
northern and eastern parts of the area primarily. Lows tonight will
remain just a tick below record warm levels as the tropical airmass
remains in place. That will set the stage for more potential heavy
rain tomorrow. It appears that the best chance for impactful
rainfall amounts will occur in western north Texas and southern
Oklahoma, where most members of the HREF develop a slow-moving MCS
and march it eastward across the area. Additional rainfall amounts
of 1-2 inches are possible, with some areas receiving up to 3
inches. Given the conditioning of soils that occurred today,
flooding remains a possibility wherever training of thunderstorms in
the MCS occurs. Given meager instability, severe weather is
unlikely, but a few stronger storms may have gusty winds.
Meister
&&
.LONG TERM...
(Wednesday night through next Monday)
Issued at 252 PM CDT Tue Oct 24 2023
Strengthening southwest flow aloft across a broad portion of the
central United States will encourage deepening of the lee trough
during the day on Thursday. The Gulf will continue to be wide-open,
so PWATS 2-3 standard deviations above normal will continue and
subsequently lows Thursday morning will still be in the low 60s for
most of the area. Warmer temperatures aloft should preclude
thunderstorm development Thursday afternoon, and the drier
conditions will mean a warm and muggy day with highs in the low 80s.
On Friday, we enter into a new regime as a positively-tilted trough
digs into the Northwest. Although the exact timing details regarding
sensible impacts in our area are unknown, a few things remain clear:
a strong surface high will migrate from the northern prairies into
the Rocky Mountain Front region;the airmass from that source region
will be much colder than any we have seen this season; that airmass
will eventually lurch southward along the Rocky Mountain Front until
it gets here.
The front that pushes the cold air may not arrive until Sunday, per
slower solutions such as the 12Z ECMWF. If that is the case, a
predecessor cold front will make it into our area Friday and stall
out either near or just south of the Red River, with the potential
for heavy rain and storms near the front where overrunning moisture
leads to elevated instability. Or the Arctic front may arrive late
Saturday, as the GFS suggests, with the predecessor front stalling a
little further north and a wet Saturday in the cards for central and
northern Oklahoma. Or, as the 12Z NAM (which is just now coming into
range) might suggest, this may just be a one-front deal - the
shallow cold airmass ushered in by the Arctic front might just get
here Friday night. We cannot say with 100% confidence which scenario
is correct, but usually the NAM has a better sense than its global
counterparts with shallow cold airmasses. One this is for sure: once
the cold air gets here, it will be here to stay until the middle of
next week.
Some more chances for precipitation will occur Sunday and Monday as
the cold front aloft pushes into the area. Right now, global models
suggest surface temperatures remaining warm enough that this will
all fall as rain. But, it would not take a very large (and very
common) warm bias in the global models for a cold rain event in
those days to potentially shift into a freezing rain or sleet event.
This bears watching as we get closer and models become more
trustworthy.
The bottom line: it will be getting much colder by the end of the
weekend, and more chances for precipitation will ensue.
Meister
&&
.AVIATION...
(06Z TAFS)
Issued at 1049 PM CDT Tue Oct 24 2023
Poor flight conditions are expected throughout most of the
forecast period. MVFR to IFR cigs are persisting and developing
over all terminals tonight. Some BR will also result in reduced
vsbys mainly near central OK. Another round of showers and
thunderstorms will enter southwestern OK around 9-10Z, and spread
east northeastward into central OK ~14Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 70 66 72 63 / 100 60 80 90
Hobart OK 76 65 73 61 / 100 60 90 70
Wichita Falls TX 76 67 76 64 / 90 60 90 90
Gage OK 79 62 75 57 / 70 20 40 40
Ponca City OK 70 66 74 61 / 100 60 70 90
Durant OK 80 67 81 66 / 60 60 30 90
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch through Thursday afternoon for OKZ023>025-027>030-
037>041-044>046-050.
TX...Flood Watch through Thursday afternoon for TXZ085-086-088>090.
&&
$$
SHORT TERM...04
LONG TERM....04
AVIATION...03