Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/23/22
Area Forecast Discussion
National Weather Service Des Moines IA
653 PM CDT Sat Oct 22 2022
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Saturday/
Issued at 252 PM CDT Sat Oct 22 2022
--Warm, well above normal, temperatures continue this weekend.
--Windy Sunday with elevated fire danger.
--Conditional severe threat Sunday night, few storms possible.
--Rain persists through Monday with cooler, more seasonal,
temperatures to start new work week.
Upper-level pattern this morning showed
quasi-zonal flow across much of the central US as a trough moved on
shore in the Pacific Northwest. This trough is expected to dig
further south through the day today transitioning our upper-level
flow to be out of the southwest and bringing ample warm air
advection into the area into tomorrow. At the surface, a boundary
bisected the state overnight causing quite a gradient in low
temperatures with areas in northwest Iowa, north of the boundary, in
the 30s and 40s while southwest Iowa, south of the boundary, saw low
temperatures in the mid 50s to even near 60! This boundary location,
and the associated warm air south of the boundary, was the
difference between a low temperature of 55 in Des Moines versus a
low temperature of 37 in Ames!
This surface boundary has since lifted north toward the IA/MN border
as a warm front with temperatures by 10AM already near to above
normal for high temperatures this time of year. (For reference,
average temperatures this time of year are the upper 50s-low 60s for
Highs and upper 30s to low 40s for Lows.) Thus, as advertised, our
temperature pendulum has shifted to be around 20 degrees above
normal today into tomorrow, up from the near 20 degrees below normal
to start the work week. With ample sunshine and decent mixing, high
temperatures this afternoon are still on track to climb into the low
to mid 80s which is certainly approaching near-record heat, though
no records are currently forecast to fall at any of our climate
sites. An increasing pressure gradient over the area has led to
breezy winds out of the south gusting to around 20-30 mph. Paired
with relative humidity values in the upper 20s-low 30% range,
somewhat elevated fire weather conditions will persist this
afternoon with fully cured crops and near to fully cured grasses,
especially in northwest Iowa where fire weather conditions are most
The warm, windy, and elevated fire weather conditions are expected
to persist into tomorrow with the approach of a deepening surface
low that is ahead of the also deepening upper-level trough. The
surface low is expected to lift from NE/SD northeast through the day
towards the ND/MN border into late tomorrow night. This deepening
low will help increase winds even more tomorrow with gusts of 35-45+
mph becoming common into the afternoon as seen in forecast
soundings. Some soundings indicate even deeper mixing with stronger
gusts at the top of the mixed layer, but not necessarily thinking
these are representative, especially the GFS which tends to over-mix
the boundary layer. With theta-e also increasing through the day
tomorrow, relative humidity values only bottom out in the 40-50%
range but despite this, the robust and gusty winds with overall dry
conditions will still elevate fire weather conditions given the
cured conditions mentioned above. This will certainly elevate fire
weather conditions and at least one of a fire weather headline or
wind advisory headline will likely be needed in at least our west
given these conditions. Temperatures tomorrow will remain well above
normal and may cause some temperature records to fall. See the
climate section for the current record high temperature values.
Although much of tomorrow will remain dry, a conditional severe
threat remains tomorrow evening. Few of the CAMs kick off any
convection before 00Z Monday (Sunday evening) and are likely tied to
the over-mixed GFS thermodynamic profile. The NAM continues to show
a strong elevated mixed layer that will be difficult to overcome
while the HRRR is generally drier. Thus, our thunderstorm and severe
weather chances are tied to timing of the front/large scale ascent
and how/if we can erode the elevated mixed layer. A strong low-level
jet does kick in tomorrow night which could certainly help kick-
off some storms given very robust shear profiles that could
certainly kick off strong wind gusts even with some weaker
storms. High LCLs and overall updraft strength would generally not
favor severe convection other than the aforementioned wind
threat. Will continue to monitor trends and see SPC Day 2 outlook
for a few additional details.
If any storms do kick off tomorrow night, they will ultimately
transition to post-frontal rain as a cold front passes through the
area late tomorrow night into Sunday. The rain looks to persist into
Tuesday in southeast Iowa with cooler, generally more seasonal
temperatures to return to start the new work week.
.AVIATION.../For the 00Z TAFS through 00Z Sunday evening/
Issued at 653 PM CDT Sat Oct 22 2022
VFR conditions are expected across all terminals through the
period. Winds will decrease slightly over the next few hours but
will remain slightly breezy across the state with gusts around 15
to 20 knots. Mainly upper level clouds are expected to move into
the state after sunrise Sunday as the next system approaches from
the west, though dry conditions are expected through much of the
day. Winds will increase, with gusty conditions after 12z through
the rest of the period up to 30 to 35 knots, and even higher at
Issued at 252 PM CDT Sat Oct 22 2022
Current Record Highs Sunday Afternoon (10/23):
Des Moines: 84 (1899)
Waterloo: 86 (1899)
Mason City: 82 (1963)
Ottumwa: 83 (1963)
Lamoni: 84 (1921)
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
643 PM CDT Sat Oct 22 2022
.DISCUSSION...(This evening through Saturday)
Issued at 221 PM CDT Sat Oct 22 2022
Key Forecast Messages:
* Today`s Fire Weather:
The wind has been just a little lighter than
expected and thus rather than having near critical fire danger
this afternoon with gusts up to around 20 mph, rather we have
been seeing winds generally around 10 mph. Consequently,
despite the very low RH values the fire danger today has been
* Sunday Fire Weather:
Issued a Red Flag Warning for the entire
forecast area. The strong wind gusts (40-50 mph) are close to a
sure thing on Sunday and given the drought conditions will go
ahead and issue the Red Flag Warning for all areas including for
where there is more questionable/higher RH values over our
eastern zones. RH values around or below 20 percent Sunday
afternoon from Hwy 281 westward is a good bet, but RH values may
bottom out more around 20-30 percent east of Hwy 281. The Red
Flag Warning will run all of Sunday afternoon through 8 pm
Sunday evening and may possibly need to be extended a bit later
into the evening.
* Sunday Severe Thunderstorm Potential:
Will be watching for
where the dry line sets up late Sunday afternoon and evening.
The 12Z models have some pretty big differences regarding how
far east the dry line will push through the area on Sunday. The
HRRR and RAP are the most aggressive with a less well defined
dry line that ends up largely east of our area by Sunday
afternoon, while the NAM and NAM NEST have a more well defined
dry line that establishes itself across our eastern zones. If
the dry line rushes east of our forecast area Sunday afternoon
then any real threat for severe thunderstorms will head east
with the dry line. However, if the dry line stalls out over our
southeastern most counties then we could see a limited window
for possible severe weather Sunday evening. The primary severe
weather threat would be thunderstorms bringing even stronger
winds down from aloft. There is also really strong wind shear
including low level wind shear so can not rule out a small
chance for a tornado, but timing primarily after dark and with
weak instability this would be a very minimal but still possible
threat. Most likely scenerio is that only a very small portion
of our southeastern forecast area will see even a small chance
for thunderstorms unless things really slow down.
* Much Cooler Next Week:
After abnormally warm high temperatures
in the 80s again on Sunday, temperatures will fall off
significantly behind the storm system with highs on Monday only
in the 50s. In fact, most of the week will see highs only in the
50s, but perhaps some lower 60s on Tuesday.
* Next Storm System Enters Plains Thursday/Friday:
At this time
the next storm system does not appear to be on a favorable track
to give us our much needed precipitation with the system
projected to take a more southerly track across the southern
plains. We could still see some precipitation/rain with the
upper trough currently favoring Thursday/Thursday Night.
* Climate Note (Near Record Highs Today and Sunday):
Saturday Record Highs Sunday Record Highs
Grand Island 91-1899 Grand Island 88-1927
Hastings 90-1927 Hastings 90-1927
Forecast: 85-87 Forecast: 85-87
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 630 PM CDT Sat Oct 22 2022
VFR conditions are expected through the morning hours
Sunday...with some blowing dust likely resulting in MVFR VSBYS
during the afternoon hours as winds gust to around 40 KTS.
Overnight...expect steady southerly winds to continue as the
pressure gradient tightens ahead of a surface low intensifying to
our west. Contemplated adding some LLWS...but the main axis of
any LLWS should be closer to the Missouri river valley and east of
As the atmosphere then begins to mix during the late morning
hours Sunday...expect winds to increase...eventually gusting to
near or greater than 40 KTS during the afternoon hours. These
strong winds should help stir up dust across the area...resulting
in areas of blowing dust...hazy skies and reduced visibilities.
There is a very small chance of an isolated thunderstorm near and
just ahead of a passing cold front late in the day...but the
better moisture will be to our east...and do not think either
terminal will be impacted and left out any mention for the time
NE...Red Flag Warning from noon to 8 PM CDT Sunday for NEZ039>041-
KS...Red Flag Warning from noon to 8 PM CDT Sunday for KSZ005>007-
Area Forecast Discussion
National Weather Service Indianapolis IN
1152 PM EDT Sat Oct 22 2022
...Updated Aviation Discussion...
Issued at 937 PM EDT Sat Oct 22 2022
High clouds along with some mid clouds will continue to move across
central Indiana overnight as an upper trough moves nearby. Adjusted
sky cover based on latest trends seen on satellite and in
observations. Not expecting any sprinkles from the mid clouds as the
atmosphere remains dry in the lower levels.
Temperatures look on track given the expected conditions, so made no
changes to low temperatures.
.Short Term...(This evening through Sunday)
Issued at 255 PM EDT Sat Oct 22 2022
* Well above average temperatures persist through the weekend
* Dry and breezy conditions accompany the warmth
Deep trough diving southeast across the West phases with the
subtropical jet resulting in a rapidly deepening surface low across
the Northern Plains by Sunday. Ahead of the developing system, upper
ridging builds across the Midwest as the subtropical jet surges
north allowing a more moist and warm airmass to spread into the
This evening and Tonight...
Current satellite imagery and surface analysis show mainly dry
conditions across the region with a few high clouds moving in from
the southwest. Left exit region of the subtropical jet is currently
located around SE KS/ SW MO placing the midwest in an area of upper
level divergence and enhanced lift. Moist air advection aloft
combined with a favorable region for lift has result in high clouds
over the Ohio Valley and Indiana this afternoon and evening. These
clouds are forecast to push northward tonight then clear out
tomorrow morning. Only impact from them will likely be keeping low
temperatures from dropping much overnight.
Still keeping an eye on RH values this afternoon as 18z IND ACARS
soundings still shows a very dry layer around and under 2 km with
dew points as low as -25C. The inversion this afternoon has already
broken and mixing is occurring up to around 0.5 km, just under the
very dry layer above. With continued warming, there is a chance low
level lapse rates may steepen enough to break the subsidence
inversion above it and allow much drier air to reach the ground. If
this does happen, low RH values in the 30s would only be present for
a few hours during peak heating this afternoon and evening. Keeping
the SPS for elevated fire risk out through the evening. Do not
believe conditions will warrant an upgrade to a Red Flag Warning.
With such a tight pressure gradient, winds may remain elevated
overnight around 4 to 10 kts which will also prevent temperatures
from falling too much. Overnight lows in the upper 50s to near 60
will make it feel more like summer than late October!
Subtropical jet begins to lift north as it phases with the trough
out west. The best warm and moist air advection remains to the west
as the core of the strong 35 to 50 kt low level jet runs along the
Mississippi River in MO and IL and points northward; however still
expect some increase in both temperatures and humidity on Sunday
locally. Tight southerly pressure gradient will result in another
breezy afternoon with steep low level lapse rates likely mixing down
higher gusts of 20 to 25 kts down to the surface. With 850 mb
temperatures around 11-13C and abundant PBL heating and mixing, high
temperatures approaching 80 degrees is likely for a few locations
around Central Indiana. RAP forecast soundings show mixing heights
upwards of 1 to 1.5 km tomorrow and with modest moisture advection
through the entire column, fire weather conditions will be limited
as Min RH values should not fall below the mid 30s to around 40
percent range. Still will keep an eye on forecast and ACARS
soundings as guidance has had a moist bias lately this month.
Expect mid and high level clouds to begin advecting into the region
from the south and west late Sunday afternoon into Sunday evening
ahead of the developing system in the Plains begins and as the
subtropical jet pushes northward. By late Sunday afternoon, the
strong low level jet begins to inch closer to the region increasing
moisture advection through the column. That combined with weak
isentropic lift should lead mid and higher clouds moving into the
region. Expect this trend to persist into Monday.
Overall a warm, dry, and breezy end to the weekend for Central
.Long Term...(Sunday night through Saturday)
Issued at 255 PM EDT Sat Oct 22 2022
* Above-average temperatures continue into next week
* Breezy and dry, with elevated but non-critical fire weather
conditions possible through Monday
* Increasing confidence for rain Tuesday into Wednesday
Saturday Night into Monday
Strong southerly flow ahead of a deepening west coast trough will
continue through the weekend. A persistent LLJ between 40-50kts at
850mb has dramatically increased temperatures over the past couple
days. Additionally, low-level moisture advection has been
increasing. Very dry surface fuels, between 5-6 percent, are present
across most of the region. With no rain expected, dry surface fuels
should persist into next week. A tight surface pressure gradient and
diurnal mixing will create windy conditions at times. Enhanced
downward momentum transfer during peak mixing may tap into the LLJ,
producing gusty winds at times. Wind gusts between 20-30mph are
possible at times through Monday, mainly during the afternoon hours.
Winds may gradually gain a slight southeasterly component on
Sunday which could allow some dry air to advect into the area.
Combined with the warm temperatures, relative humidities drop to
as low as 30-35 percent at times. Therefore, elevated fire
weather conditions are possible through Monday. Critical fire
weather thresholds are not currently anticipated, due to increase
low-level moisture advection preventing excessively dry RH
High-level moisture advection should also increase ahead of the
western trough. Intervals of cirrus clouds are likely until thicker
cloud cover arrives later on Monday. High temperatures each day
should top out in the mid to upper 70s, with a few locations
reaching 80. A tight surface pressure gradient will maintain breezy
conditions into the night, preventing low temps from dropping beyond
the mid 50s.
Tuesday into Wednesday
The deep western trough is modeled to reach its peak strength midday
Sunday. After this, guidance splits the trough into two distinct
pieces of energy, with one racing off the the northeast into Canada
and another lagging behind in the four-corners region. The northern
piece should pass well to our northwest, and any precip associated
with this feature should not affect Indiana. The southern piece of
energy, however, will eventually bring impactful weather to our
To the southwest of the deep trough, a cut-off low is located
off the coast of Baja California. As this feature moves
northeastward, guidance phases it with the southern piece of energy.
Cyclogenesis then begins across the southern Great Plains on Monday.
Confidence lowers after this point, but has generally been
increasing as guidance comes into agreement on the track and timing
of the low. The northern jet stream reconnects over the US-Canadian
border and the phased southern system becomes partially cut off.
This may limit the amount of strengthening the system is capable of
before reaching Indiana. Peak intensity occurs just upstream,
somewhere over Missouri or southern Illinois, with weakening
thereafter. Precipitation amounts and thunderstorm probabilities
will depend on timing and how strong the system is when it arrives.
Thursday through Saturday
After the passage of Tuesday`s system, temperatures begin to warm
once again. With the northern branch of the jet stream reestablished
north of the departing system, broad ridging and warm air advection
quickly resumes on Thursday. Temperatures rebound into 60s to close
out the week along with dry weather. Ensemble guidance hints at
another trough entering the Plains on Friday in a split flow
pattern, which could bring rain back into the forecast by Saturday.
Chance PoPs have been added though confidence is quite low.
.Aviation...(06Z TAF Issuance)
Issued at 1152 PM EDT Sat Oct 22 2022
- Winds 160-180 degrees will increase to 12 to 17 knots with gusts
over 20 knots after 14z
- Non-convective low level wind shear possible at KLAF and KHUF 12z-
Status quo regarding breezy afternoon southerly winds that will gust
over 20 knots by mid morning and near 30 knots in the afternoon,
mainly at LAF. In addition, persistent dry column leads to very high
confidence in VFR flying conditions with just passing cirrus and
mainly overnight as an upper trough swings through.
Non-convective low level wind shear is possible for a few hours
toward daybreak, mainly at KLAF and KHUF.
Area Forecast Discussion
National Weather Service Jackson MS
946 PM CDT Sat Oct 22 2022
...New MESOSCALE UPDATE...
Issued at 946 PM CDT Sat Oct 22 2022
00Z synoptic & RAP analysis this evening indicates slow moving
shortwave trough at 500mb just off the Atlantic seaboard. Mid-
level ridge axis has built E into the Appalachians, with faster
quasi-zonal flow for areas in the S CONUS along & W of the MS
River Valley to the W Coast. Some increased upper jet support &
isentropic ascent will keep some increased moisture aloft &
scattered high-level cloudiness. Strong 850mb LLJ remains over
the Plains, with low-level ridge centered over the Appalachians.
Our region remains under good SW return flow. 00Z regional sfc
analysis indicates 1022mb sfc high remains situated over the
Appalachians & deepening sfc low over the lee side of the
Rockies/Plains. This continued increased gradient will persist
into the overnight hours, keeping some increased winds across the
NW Delta, mainly along & NW of a line from Natchez to Greenwood.
Winds will keep lows above normal into low 60s along & NW from a
Natchez-Greenwood, while closer to normal in the E into upper 40s
to near 50 degrees. Main adjustments were to bump up lows a touch
in the Delta while a tad cooler in the E. Fog potential looks to
remain low as crossover potential looks less than last night.
Updates are out. /DC/
Issued at 211 PM CDT Sat Oct 22 2022
Through Sunday: A relatively dry airmass will remain in place across
the area. We`re still situated on the western periphery of a surface
ridge extending along the East Coast. The tightening pressure
gradient between this feature and a developing cyclone on the
leeside of the Rockies will result in continued breezy conditions,
with southerly wind gusts this afternoon and again during the
daytime tomorrow up in the 25 to 30 mph range (especially for areas
farther north and west). We received one report this afternoon of
blowing dust in the vicinity of dry fields in southeast AR. With
winds persisting overnight, low temps will trend a few degrees
upward tonight from last night. Similarly, highs on Sunday will be
near or a few degrees warmer than today. /DL/
Models are beginning to come into better
agreement regarding the chance and timing for severe weather
Tuesday as an area of low pressure moves through the region. The
current slight risk area will be sustained for Tuesday morning
into Tuesday afternoon. There will also be a potential for gusty
winds ahead of the front Monday into Tuesday as a pressure
gradient begins to tighten as the low approaches. Further details
about these threats are outlined below.
A closed low will track across north Texas towards Tennessee
Monday night into Tuesday. At the surface a cold front should be
moving into northeast Louisiana and southeast Arkansas around
sunrise on Tuesday. Sustained winds will likely be in the 15 kt
range with gusts around 20-25 kts across the CWA Monday and
Tuesday ahead of the front. Monday night will be relatively warm
as the front begins to pass through. Though poor lapse rates in
the early morning will likely limit severe potential, models show
there will be a narrow corridor of MLCAPE greater than 400 J/KG
stationed ahead of the front to support thunderstorm development.
Deep layer wind shear in the environment as the front begins to
pass through the area will be in excess of 40kts which is
favorable for supercellular development. Forecasted hodographs
show decent low level wind shear and helicity supportive of
tornadoes as well. Since this is still 4 days out changes in
timing and strength of the features could alter the forecast.
Tuesday evening will likely yield cooler temps and warming trend
will soon follow. Quiet weather will be expected until our next
chance of rain Friday into Saturday. At this time severe weather
doesn`t look likely with this system. /NP/
Issued at 650 PM CDT Sat Oct 22 2022
VFR flight cats will prevail through the next 24 hours. Southerly
gradient winds will lighten this evening & increase again during
the day Sun, mainly after 23/15-16Z. Increased gradient winds are
expected across central-N TAF aerodrome sites (i.e. JAN, HKS,
GTR, GWO & GLH). Sustained winds up to 20mph, with gusts up to
25-30mph, are expected, especially in NW sites at GLH & GWO. /DC/
.PRELIMINARY POINT TEMPS/POPS...
Jackson 56 81 57 80 / 0 0 0 0
Meridian 49 79 52 78 / 0 0 0 0
Vicksburg 59 84 59 83 / 0 0 0 0
Hattiesburg 50 82 56 81 / 0 0 0 10
Natchez 59 83 59 82 / 0 0 0 10
Greenville 62 84 59 83 / 0 0 0 0
Greenwood 59 82 57 81 / 0 0 0 0
Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
933 PM EDT Sat Oct 22 2022
Issued at 931 PM EDT Sat Oct 22 2022
A weakening upper level short-wave is moving across the
Ohio/Tennessee valleys. Only areas of high level clouds associated
with this wave. Surface ridging will remain producing calm winds.
Made some minor changes to temperatures, otherwise current
forecast looks good.
(This evening through Sunday)
Issued at 247 PM EDT Sat Oct 22 2022
1. Temperatures a few degrees above normal for the short term.
2. Another afternoon of relative humidities largely falling into the
30% range on Sunday. Localized areas may creep into the mid to upper
Most recent satellite trends show some high clouds streaming in from
the west associated with shortwave activity and strong southwesterly
850mb flow upstream. At the surface, dewpoint temperatures in the
mid to upper 30s and temperatures a few degrees above normal have
resulted in relative humidities falling largely into the 30% range,
with a few localized spots creeping into the 20s. A few very very
weak radar returns have been present across central Tennessee this
afternoon as well. These continue to dissipate as they transition
eastward and suspect that if any return were to survive into the
region this would end up as virga given the very dry low levels.
The overnight period will continue to be quiet as little to no fog
is expected... once again thanks to a lack of low level moisture.
Depending on how well clouds clear/thin during this period, areas in
close proximity to lakes/rivers could be the exception. For the
afternoon, low RHs will continue to be the focus point. Model
derived soundings continue to show a very dry airmass in both the
mid and low levels, with GFS suggesting mixing heights around 4-
5kft. Given weak flow aloft winds will remain calm/light.
Generally have afternoon RHs falling into the 30s with southern
valley locations into the upper 20s. There are a few models, such
as the HRRR and GFS, that have notably lower Tds than other
guidance which would result in even lower RHs. Have made sure to
include a mention of these low RHs in the FWF. Otherwise, another
pleasantly warm day is on tap Sunday.
(Sunday night through next Saturday)
Issued at 247 PM EDT Sat Oct 22 2022
1. A warming trend will continue early in the week with dry
conditions until increasing rain chances later on Tuesday.
2. Gusty winds are possible in the mountains Tuesday night, in
addition to an embedded thunderstorm or two.
3. Drier and milder conditions will return later in the week,
followed by more low-end rain chances into the weekend.
Sunday Night through Wednesday
At the start of the period, troughing will be noted over the Rockies
with ridging in the eastern CONUS. Surface high pressure will remain
with a developing shortwave/closed low coming into focus in the
southwestern U.S. As the feature ejects into the Southern Plains,
cyclogenesis will take place with increasing ridging and southerly
low-level flow moving towards the region. This will continue the
recent warming trend with similarly dry air remaining in place. As
such, this will keep the heightened focus on fire weather due to
efficient mixing and gradually increasing wind gusts. By Tuesday, it
is indicated that the upper-level shortwave becomes significantly
more negatively tilted over the lower Mississippi River Valley
before approaching the area. With limited moisture return until the
evening and increasing downsloping, heightened fire weather concerns
will remain before later in the day.
By Tuesday evening into the night, the aforementioned
shortwave/closed low will move into the region with continued
consensus for a weakening of the upstream jet. In any case, the jet
core is still indicated to be near 100 kts with broad upper
divergence in the left-exit region over our area. This will also
work to strengthen the low-level jet with the surface low deepening
to 1,000mb or less near West Tennessee. There still remains
differences in the evolution and track of the system, but confidence
is increasing that 850mb winds could reach or exceed 50 kts near our
area, which would definitely raise potential for mountain wave
winds. Additionally, wind profiles ahead of this system are forecast
to be strongly veered from the surface to near 500mb. As always,
there remains a lot of uncertainty as to if the warm front will
reach southern portions of the region. Given all of these questions,
HWO wording was increased only to low probability wording on this
shift. However, if the GFS or solution or future NAM runs stay
persistent, the region could certainly be faced with mountain wave
winds and severe weather potential in the south. This event will
hopefully bring rainfall to portions of the area that are in
moderate or greater drought. By Wednesday, the flow becomes more
quasi-zonal with lingering moisture lifting to the northeast.
Thursday through Saturday
Later in the week, high pressure will remain in place to the north
with milder temperatures returning due to more northerly flow. By
the end of the period, another trough is indicated to move towards
the region. As of right now, the main message looks to be a return
of rain chances with impactful weather not expected at this time.
Issued at 713 PM EDT Sat Oct 22 2022
VFR conditions expected across the TAF sites throughout the
forecast. Surface ridging will remain over east Tennessee. A fast
moving weakening short-wave will move across the Ohio and
Tennessee valleys producing a good deal of high level cloudiness.
Winds will remain light and less than 10kts through the forecast
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 47 74 48 76 / 0 0 0 0
Knoxville McGhee Tyson Airport, TN 44 75 45 76 / 0 0 0 0
Oak Ridge, TN 44 74 45 75 / 0 0 0 0
Tri Cities Airport, TN 40 72 43 74 / 0 0 0 0
Area Forecast Discussion
National Weather Service Mount Holly NJ
958 PM EDT Sat Oct 22 2022
High pressure will give way to coastal low pressure that will
bring some unsettled weather to our region Sunday into Monday.
Weak high pressure returns for Tuesday, then a cold front is
forecast to move through later Wednesday. High pressure then
builds to our north Thursday through Saturday.
.NEAR TERM /THROUGH SUNDAY NIGHT/...
Forecast remains on track as we head into the late evening.
Latest HRRR seems more in touch with reality, and keeps rain
offshore until 7 or 8 AM, then reaching the I-95 corridor around
midday. Earlier this evening we made some adjustments to timing
and northwest extent of rain incoming from coastal low pressure
currently developing to the southeast of Cape Hatteras. The
overwhelming consensus from the latest modeling was in support
of keeping the I-95 corridor northwestward dry through midday
Sunday. Light to moderate rain looks more likely area- wide,
especially to the southeast of I-95 in the afternoon and
evening. However, areas of eastern PA, especially farther NW
toward Reading and Allentown, look like they could end up with
just some spotty light rain or sprinkles tomorrow. Some of the
hi-res models and the NBM guidance are particularly dry, with
only a few hundredths of an inch even for the Philadelphia area.
Did not go that dry with the current forecast, but we`ll have
to continue to monitor trends and message the uncertainty.
Either way, we are still looking at some relatively light
amounts of beneficial rain tomorrow and tomorrow night. Total
amounts along the shore and coastal Delmarva could reach near a
Otherwise, latest analysis depicts a ridge of surface high
pressure still holding over our region, extending from northern
Georgia northeastward to near Nova Scotia. However, southeast of
Cape Hatteras and northeast of the Bahamas, surface low
pressure is slowly taking shape. Aloft, a closed low is sitting
south of Cape Hatteras and north of the Bahamas, just west of
the developing surface low, with a ridge well east off the
Atlantic Coast and another ridge over Mexico to the southwest.
Clouds will continue to spread northward and thicken across our
area thru tonight as the low pressure starts moving north. For
the most part, clouds tonight should be of the high variety this
evening, but some mid level clouds could make their way inland
later on. Overall however, dry surface conditions will prevail.
The increased clouds and increasing dew points thanks to
developing easterly flow should hold lows up noticeably compared
to recent nights, with 40s common, and warmer spots especially
near the coast likely to stay in the 50s overnight.
Guidance remains unusually uncertain about the spread of
rainfall with the low pressure as it moves northward, almost
like what we might find with a winter-time system, but as a wise
meteorologist once told me, "you`ll always find a surprise
under a closed low". That said, confidence has increased
regarding precipitation reaching the coast, but staying away
from the far western zones. Thus, have high likely to low end
cat pops for the southern NJ/DE coast on Sunday into Sunday
night, with slight chance in western Berks etc. In between,
still a lot of uncertainty about how far west rain can manage to
get. The clouds and rain chances will hold temps down compared
to today, with low-mid 60s much more common than todays near 70.
Northeast winds and cloud cover will also make it feel notably
cooler than the thermometer suggests.
Most guidance shows the initial wave of precip pushing north of
the area overnight Sunday, though the latest EC actually has
the greatest precip extent (if not amount) occurring late Sunday
night. In any case, overall the guidance agrees that the risk
of precip should overall decline as we head thru Sunday night.
The clouds and moisture plus easterly flow should add a further
bump to overnight lows, with much of the area struggling to fall
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
An upper-level trough lifting up the East Coast is forecast to
gradually weaken with time. Surface low pressure associated with
it also tracks northward, however the positioning and strength
of this feature is less certain. An onshore wind component will
be maintained through most if not all of this time frame, and
this should tend to lock in the low-level moisture. As a result,
lots of clouds are expected although clouds bases may end up
lifting with time. It will tend to start getting more humid
Tuesday as dew points are forecast to climb into the low 60s for
much of the region.
Regarding precipitation chances, we will continue to keep PoPs
on the low side given the uncertainty. While there could be at
least some showers around especially Monday, some guidance such
as the NAM may be overdone with its extensive low-level moisture
and therefore measurable precipitation. Temperatures will
depend on the extent of the cloud cover (low stratus versus
higher cloud bases) given the onshore flow. Overall, did not
change the forecast drastically given more uncertainty although
did increase the cloud cover some for much of the area
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Summary...Potentially unsettled at times, however temperatures
on the warmer side through Friday before potentially much cooler
air arrives to start the weekend.
Synoptic Overview...An upper-level trough sliding across the
Great Lakes Wednesday may take on a negative tilt as it lifts up
into portions of eastern Canada. Surface low pressure with it
will pull a cold front across our area later Wednesday. Some
ridging may try to follow for the end of the week and to start
the weekend, with surface high pressure tending to build to our
For Wednesday and Thursday...The upper-level pattern Wednesday
is forecast to comprise of a trough that may take on some
negative tilt as it lifts across the eastern Great Lakes and
vicinity. Surface low pressure will accompany this and track to
our north, however a cold front will move through later in the
day Wednesday or at night. It should be more on the humid side
ahead of the front Wednesday as dew points are in the lower 60s
for many areas. Deeper moisture however may be more limited and
with the bulk of the lift potentially just glancing our area,
precipitation could be on the sparse side. The flow aloft starts
to then flatten Thursday as high pressure begins to build
across the Great Lakes region.
For Friday and Saturday...The overall pattern suggests that a
bit of ridging is across the Northeast which supports
potentially strong surface high pressure building across to our
north. It almost looks more like a winter pattern setup with the
surface high becoming centered near Maine early Saturday, which
then wedges southwestward (cold air damming scenario).
Meanwhile, energy sliding across the Gulf coast states should
support low pressure along a frontal zone. For our region, a
northeasterly low-level flow is forecast to be in place thanks
to strong high pressure to our north. This should result in
cooling along with potentially more cloudiness from off the
ocean. The precipitation chances are less certain with high
pressure anchored to our north-northeast trying to deliver drier
air within an onshore low-level flow.
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Tonight...VFR, though with cigs above 10000 ft thru the night
as low pressure gradually approaches from the south. Winds
mainly 5 kt or less, but toward the coast becoming NE 5-10 kts
with some gusts to 15 kts by morning. High confidence.
Sunday...Prevailing VFR in the AM, then much uncertainty by late
in the day as low pressure moves north and potentially spreads
rain to all terminals except by evening, except maybe ABE/RDG.
Best chance is of rain and lower CIGs is at KACY, with
decreasing chances NW of there. Cigs near the coast may drop
below 2k ft later in the day, while KRDG may not drop to 5k ft
until Sunday night. Vsby likely mostly VFR, though steadier
rain especially near KACY may bring vsby down below 3sm. Low
confidence in the timing/details this period.
Monday and Tuesday...Sub-VFR ceilings may linger for much of
this time. Some showers are possible, especially Monday. North
or northeast winds 10 knots or less Monday, becoming east to
southeast Tuesday. Low confidence.
Wednesday...VFR overall, however some showers possible in the
afternoon and at night. Southeast to south winds less than 10
knots, becoming west to northwest 5 knots or less at night.
Thursday...VFR. Northwest winds 5-10 knots. Moderate
Coastal low pressure moving northward is bringing northeasterly
winds generally 8 to 12 kt across the coastal waters this
evening. As this low continues northward and high pressure holds
firm to our north, winds will increase to 15-20 kts with gusts
up to 30 kts on Sunday. Winds peak during the afternoon then
diminish Sunday night. However, keep SCA in effect for ocean
waters thru early morning Monday because seas likely build to
5-8 ft and they won`t subside below SCA until Monday morning.
Kept SCA off the bay where lighter winds and lower waves should
Monday...Seas are anticipated to be subsiding below 5 feet on
the Atlantic ocean zones, otherwise the conditions are forecast
to be below Small Craft Advisory criteria.
Tuesday through Thursday...The conditions are anticipated to be
below Small Craft Advisory criteria.
MARINE...Small Craft Advisory from 6 AM Sunday to 6 AM EDT Monday for
Area Forecast Discussion
National Weather Service Topeka KS
620 PM CDT Sat Oct 22 2022
Issued at 250 PM CDT Sat Oct 22 2022
-Strong winds ahead of a developing storm system could bring red
flag conditions to parts of the area Sunday. There will also be a
slight risk for severe storms late Sunday evening into Sunday
-Rain and much cooler temperatures are in the forecast Monday.
The strong upper trough now digging into the central Rockies will
continue to deepen low pressure across the central high plains
overnight. Moisture advection will also continue with sfc
dewpoints expected to rise into the middle to upper 50s by sunrise
Sunday. On Sunday...energy in the trough will split with the northern
stream energy forecast to emerge into western Nebraska/SD region
where HT falls will maximized. This should help to force a
dryline to the northeast into some part of central Kansas.
Guidance is varied in how far east the dryline will mix during the
afternoon with the HRRR the most aggressive and other models
keeping it west of our area until after 00z. Fcst soundings at
this time only show MUCAPE of around 300 to 500 j/kg aloft with
50+ kts of 6km shear. This could pose problems for any updrafts
that attempt to organize given the modest CAPE. It appears that if
any updrafts do become sustained the greatest risk would be wind
given the 50-70 kts of 900-800 mb flow.
What appears most likely is a shallow line of showers or t-storms
immediately along the boundary Sunday night into early Monday
morning. More widespread rain and thunderstorms could then
overspread the area from OK as another wave develops along the
boundary. Recent trends suggest the greatest chance for rain along
and east of the turnpike. Highs will be much cooler in the 50s and
The next chance for rain appears Thursday night into Friday as
another upper low tracks across the region.
.AVIATION...(For the 00Z TAFS through 00Z Monday)
Issued at 620 PM CDT Sat Oct 22 2022
Winds will be the main driver of the forecast. Forcing doesn`t
look to pick up until after 00Z Monday and moisture in the lower
troposphere looks to remain limited. So just some increasing high
clouds are expected through the day Sunday. Forecast soundings
show mixing throughout the night with a shallow inversion. Think
this may reduce the chances fore LLWS. But will hold onto the
LLWS in the forecast since the prev shift had it in and it`s
potential to affect general aviation more so than commercial
Issued at 255 PM CDT Sat Oct 22 2022
Winds will increase and gust from 45 to 55 mph during the day on
Sunday. The uncertainty remains on the position of the dryline
Sunday and whether it can move east into parts of north central
Kansas. If so, it would create red flag conditions across that
part of the state while areas east may see dewpoints in the upper
50s which could keep humidities in the 35 to 45 percent range.
Fire Weather Watch from Sunday morning through Sunday evening
Wind Advisory from noon to 7 PM CDT Sunday for KSZ008>012-
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
612 PM MDT Sat Oct 22 2022
Issued at 611 PM MDT Sat Oct 22 2022
00z surface analysis indicated RHes are quickly recovering into
the 20s+. Gusty southwest winds will continue to subside. Will
drop the Red Flag Warning slightly early to account.
.DISCUSSION...(This Evening Through Saturday)
Issued at 202 PM MDT Sat Oct 22 2022
Potent upper trough is currently digging into the western CONUS
with downstream pressure falls supporting cyclogenesis over WY.
Sfc front struggling to mix back north as a warm front given thick
cirrus and poor mechanical mixing. Have knocked down highs in a
few locations, esp NE of the BH where ESE flow is expected to
continue today. SFC low will deepen and push east through Sunday
as the upper trough moves east and splits. Forecast models have
now supported a stronger northern stream counterpart to the
splitting trough, with an uptick in forcing, jet dynamics over the
region, and resultant QPF. In addition, stronger CAA signal will
support a quicker switch over to snow, with snow ensuing Sunday
afternoon over NE WY. Main deformation band will setup over NE WY
into eastern MT Sunday night with a period of heavy snow expected
as the main upper jet shifts NE into the region. Thermal fields
become less supportive for heavy snow as one moves east into far
western SD given warmer thermal fields, with the main area forcing
below the DGZ. Hence not as confident with snow amounts in the
northern BH and far NW SD given the lack of a decent upslope
signature per the peak of upslope forcing residing below -10C. At
this time, it looks a like solid adv levels in NE WY and the
WY/Northern BH. In addition to snow, strong NW winds are expected
with sustained winds of 20 to 30 mph and gusts over 40 mph. If
snow amounts increase or stronger winds materialize, an upgrade to
winter storm warning would be possible in NE WY and maybe the
northern Black Hills if the system shifts slightly east. Further
SE on the SD plains, dry slotting and downslope flow off the BH
will support little to no precip after Sunday`s frontal wave,
with the main story there being the winds. Right now it looks like
solid adv numbers Sunday night and Monday, with a small window
for warning levels Monday morning from K2WX to KRAP. Given the
period, will defer wind headlines to the mid shift. System will
quickly exit the region on Monday with winds lingering (on a
waning basis) through the day, while most of the precip will
likely end in the morning. Much cooler conds then expected for the
remainder of next week with numbers just below seasonal norms.
Chances for rain/snow then return toward the end of the week with
semi-active flow as a few weak impulses cross the region.
.AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening)
Issued At 526 PM MDT Sat Oct 22 2022
Gusty southwest winds over northeast WY will subside this evening.
VFR conditions will continue tonight. A strong storm system will
bring deteriorating conditions over northeast WY Sunday morning,
spreading into northwest/far southwest SD Sunday afternoon. Low
clouds/RASN will cause IFR/LIFR conditions over northeast WY
Sunday and IFR/MVFR conditions over the Black Hills into northwest
SD Sunday afternoon. A cold front will move through the area
Sunday with gusty northwest winds (40kts) behind it slowly
spreading west to east.
Issued At 202 PM MDT Sat Oct 22 2022
Gusty SW winds will spread over NE WY and far southern SD this
afternoon supporting red flag conds there. Cloud cover and a less
aggressive northward push of the warm front will limit northward
extent of the red flag conds over western SD. Hence, the staunch
inversion in place will continue to support ESE low level flow
east and north of the Black Hills. Have decided to cancel the red
flag warning there given HRRR and observation trends. Otherwise, A
strong cold front will cross the area late tonight and Sunday,
along with an upper level system late this weekend into Monday.
This will bring much colder air, higher humidities, gusty winds,
and rain/snow from northeast WY to the Black Hills and northwest
SD...Winter Weather Advisory from 6 PM Sunday to noon MDT Monday for
WY...Winter Weather Advisory from 6 PM Sunday to noon MDT Monday for