Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/19/24
Area Forecast Discussion
National Weather Service La Crosse WI
1019 PM CDT Wed Sep 18 2024
.KEY MESSAGES...
- Above average temperatures continue into the weekend with some cooling
through early next week.
- Scattered non-severe storms possible tonight into Thursday
morning, with higher chances (60-80%) for storms late Thursday
afternoon/evening, potentially severe, especially near and
west of the Mississippi River.
- Low to medium (30-50%) rain chances continue later in the
weekend into early next week.
&&
.DISCUSSION...
Issued at 303 PM CDT Wed Sep 18 2024
Tonight-Thursday night:
GOES water vapor channels early this afternoon showed a trough
across the northern Rockies with a plume of moisture extending north
and west towards it from the plains and much drier low-level air
over the Great Lakes. The axis of stronger moisture transport will
shift east into the area later tonight and Thursday ahead of the
trough, likely resulting in scattered showers/storms, most numerous
near and west of the MS River, gradually diminishing through early
afternoon as the moisture transport weakens a bit before refocusing
late in the day ahead of the trough/front. Storms through the
morning should be non-severe.
The main focus of attention will be late in the afternoon and
evening as the front approaches and ascent increases with the
main shortwave passing by to the north. A narrow corridor of
2000+ J/kg of MLCAPE is indicated by the RAP along/ahead of the
front with cross frontal deep layer shear profiles sufficient
for supercells/updraft rotation before some upscaling/clustering
occurs through the evening. Any initial supercells could pose a
risk for large hail in excess of 1" with a plume of steeper
mid-level lapse rates ahead of the trough, especially west of
the Mississippi River. A tornado could not be completely ruled
out with any supercell with modest curvature noted in low-level
hodographs. These threats likely would be greatest earlier in
the storm life cycle before upscale growth occurs with a
wind/hail risk. Eventually, storms should weaken eastward
through the evening as diurnal cooling occurs/instability wanes.
Friday-Wednesday:
Weak high pressure builds back into the area on Friday with temps
staying above average in the mid 70s to mid 80s given only slight
low-level cooling. There continues to be spread in the model suite
with the evolution of upper level troughs progressing from the
Desert Southwest and from northern plains/southern Canada through the
weekend into early next week, especially with the amplified ridging
across western Canada. With the uncertainty in the flow progression,
rain chances remain in the 30 to 50% range Saturday night through
early in the week. A general cooling trend is expected early next
week, although global ensemble members show notably higher spread
during this time. NBM 25th-75th percentile max temps are mainly in
the mid 60s through the 70s during this time.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1015 PM CDT Wed Sep 18 2024
VFR conditions are expected through tonight with an increase in
mid-level clouds west of the Mississippi River before sunrise.
There is a 50-60 percent chance of showers associated with this
cloud deck from roughly 11-18Z, though aviation impacts look to
be limited in scope. A second round of thunderstorms (60 to 80%
chance) develops west of an RST to MCW line around 20-21Z and
moves eastward through the late afternoon and evening hours with
IFR to localized LIFR conditions in the heaviest rain. Winds
remain from the south to southeast at 5-10 kts tonight,
increasing to 10-5G20 kts for the afternoon. Westerly winds with
stronger gusts are likely under any storms in the late
afternoon and evening. Fog may develop in the wake of these
storms early Friday morning depending on how quickly clouds
clear.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...JM
AVIATION...Skow
Forecast Discussion at weather.gov/mqt.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...None.
&&
$$
MESOSCALE UPDATE...Huyck
DISCUSSION...Levens
AVIATION...Huyck
MARINE...Levens
Area Forecast Discussion
National Weather Service Sioux Falls SD
1052 PM CDT Wed Sep 18 2024
.KEY MESSAGES...
- Shower and thunderstorm chances (30%-40%) increase overnight
for areas mainly along and south of Interstate 90. The
strongest storms may be capable of producing hail to the size
of quarters.
- An active pattern aloft will lead to renewed shower and
thunderstorm chances (40%-60%) this weekend with the highest
chances occurring on Saturday and Saturday.
- Confidence continues to increase in cooler stretch of
temperatures starting as early as Sunday.
&&
.UPDATE...
Issued at 918 PM CDT Wed Sep 18 2024
Showers and thunderstorms have largely failed to materialize
this evening within broad area of increased instability ahead of
an approaching cold front - likely due the lack of substantial
forcing. That said, focus has shifted to the overnight hours
when some guidance suggests additional thunderstorms may develop
in response to an increasing 60 kt 500 hPa jet streak and 40-50
kt 850 hPa jet. In particular, multiple runs of the HRRR have
shown thunderstorms first developing near the central SD/NE
border region after midnight and then pushing east mainly along
and south of I-90 through the overnight hours. Additional storms
may develop across eastern NE and move north. With the loss of
daytime heating, the near surface layer is quite stable, but
model soundings do show roughly 1000-1500 J/kg of elevated CAPE.
This could allow for the strongest updrafts to produce some
isolated large hail up to the size of quarters. To account for
this possibility, introduced 30-40 percent POPs overnight, but
some adjustments are likely over the next several hours.
&&
.DISCUSSION...
Issued at 211 PM CDT Wed Sep 18 2024
REST OF THE EVENING/TONIGHT: Taking a look at satellite imagery,
areas of lingering stratus continue to lift northeastwards across
our eastern-most column of counties with a few pockets of light
showers. Expect this lingering activity to continue to progress
northeastwards before exiting our area around 18z. Looking
aloft, a vertically stacked ULL situated over Eastern Montana
and the far western Dakotas continues to rotate northeastwards
keeping our overall flow locked into a northeasterly regime
through tonight. Shifting gears to our precipitation chances,
isolated shower and thunderstorm could develop by as early as
21z as a subtle shortwave rotates around the ULL.
However, with rather weak forcing and a modestly stable airmass in
play due to this morning`s rain/lingering cloud cover; not too
confident in our overall severe weather chances this afternoon
and evening. Nonetheless, with up to 1500 J/kg of instability,
30-35 kts of speed shear, and a dry sub-cloud layer; can`t
completely rule out a stronger storm or two mostly between the
James River Valley and I-29 corridors with the main threats
being damaging winds up to 60 mph and quarter sized hail.
Otherwise, expect mostly quiet conditions to return overnight as
breezy southerly winds gradually decrease with the approaching
surface high. Lastly, lingering cloud cover and southerly
surface winds will keep temperatures elevated overnight as lows
gradually decrease into the low to upper 60s for the night.
THURSDAY: By Thursday morning, could potentially see a few isolated
pockets of light to moderate showers develop east of I-29 as the LLJ
strengthens ahead of the cold front. Expect this area of activity to
gradually scoot eastwards through parts of the morning with most of
the activity exiting our area by about 15z. From here, cloud cover
should begin to clear out from west to east with an abundance of
sunshine returning for the rest of the day. With this in mind,
expect our overall temperatures to stay above normal with highs
topping out in the upper 70s to upper 80s with the warmest
conditions expected across portions of the Missouri River Valley and
northwestern IA.
THE WEEKEND ONWARDS: Heading into the weekend, mostly quiet and
breezy conditions will continue as a surface high moves across the
region by Friday. A tightening SPG will lead to periodic breeziness
over the weekend with wind gusts up to 25 mph possible each
afternoon. From here, an active pattern returns aloft with a
northern stream trough progressing eastwards across Montana and an
ULL ejecting out of the four-corners region. Both these features
will likely influence the precipitation chances across our area from
Saturday through Sunday. However, to what degree is still in
question. Most long-range guidance continues to vary on the
strength of both systems which has result in some uncertainty.
Nonetheless, most ensemble guidance continues to show low to
medium confidence (30%-50%) chances of up to half an inch of QPF
with the focus being areas south of I-90 which could mean some
beneficial rain is on the way for parts of our area. Either way,
we`ll have to monitor these systems as they approach. Lastly,
the increasing precipitation chances will lead to temperatures
trending downwards heading into the new week with daily dropping
from the low to mid 80s on Friday to the low to upper 60s by
Monday.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1052 PM CDT Wed Sep 18 2024
Primary challenge will be timing and coverage of any nocturnal
thunderstorms. Recent guidance suggests there may be additional
shower and thunderstorm development overnight, especially for
areas along and south of I-90. Best chances will be at KFSD from
19.10-19.12Z, when a TEMPO for -TSRA was introduced. Less
confidence at KSUX, so will keep dry for now. KHON is expected
to remain dry.
Ceilings are expected to remain VFR through the period. If a
thunderstorm moves directly overhead a TAF airfield, could see
brief reductions down to 3500-4000 ft agl.
Still looking at low-level wind shear at KSUX overnight given
strengthening jet. While surface winds will be rather light,
expect an increase to around 40 kts at 2000 ft agl. Some
southerly breezes are expected overnight, but winds will veer
to the west-southwest through the day Thursday with an
approaching cold front. KHON in particular could see some
stronger wind gusts in the afternoon...topping out near 25 kts.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
UPDATE...Rogers
DISCUSSION...Gumbs
AVIATION...Rogers
Area Forecast Discussion
National Weather Service Green Bay WI
1047 PM CDT Wed Sep 18 2024
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- Near-record high temperatures are expected on Thursday.
- Locally dense fog is possible across mainly eastern Wisconsin
late tonight into Thursday morning.
- There is a marginal risk of severe storms in north-central and
central Wisconsin from late Thursday afternoon into Thursday
evening. Most locations are forecast to see a quarter to a half
inch of rain from Thursday afternoon through Friday afternoon.
- A pattern shift is expected this weekend, with highs dropping closer
to normal Sunday through the middle of next week. Confidence is
low on the timing/location and rainfall amounts for early next
week.
&&
.DISCUSSION...
Issued at 243 PM CDT Wed Sep 18 2024
Short Term...Tonight and Thursday
The latest RAP analysis and satellite radar imagery show a
vertically stacked low pressure system spinning over eastern
Montana early this afternoon. An arcing band of clouds is moving
east and well ahead of the system into the northern Mississippi
Valley. Cirrus along the leading edge of this cloud band is
dissipating as it spreads east across Wisconsin. Otherwise, it is
another warm September day with temps in the upper 70s to middle
80s across the region. As this upper low slowly moves east, fog
potential early Thursday morning and thunderstorm potential late
Thursday afternoon are the focus of this forecast.
Fog potential: While cirrus will continue to invade the region
from the west, conditions will be favorable for fog development
over northeast WI late tonight into Thursday morning. Models
continue to show light onshore flow off the warm waters of the Bay
and Lake combined with mostly clear skies and temps falling well
below their cross-over temps. The highest probabilities will be
just west of the Lake Michigan and Green Bay shoreline over inland
Oconto, Marinette, Manitowoc, and Kewaunee counties. Locally dense
fog will be possible starting around or shortly after midnight
through about 8-9 am Thursday morning.
Thunderstorm potential: A very dry airmass remains present over
eastern WI this afternoon where precipitable water values are
estimated at about 60% of normal. This dry airmass will shift east
as the moisture axis ahead of low pressure over the northern
plains slides into the state on Thursday afternoon. By 4 pm
Thursday, precipitable water values are expected to climb to 175%
of normal over north-central WI.
The increasing moisture will lead to a more unstable airmass
invading the region on Thursday. Thunderstorms are expected to
develop over eastern Minnesota at peak heating in the afternoon.
Some guidance develops additional thunderstorm activity further
east into central WI after 5 pm where instability will reach over
1000 j/kg. If storms can move into central WI before nocturnal
cooling sets in, a few strong storms appear possible due to deep
layer shear over 30 kts and dcapes over 1000 j/kg.
Temperatures: A little warmer on Thursday with highs in the low to
middle 80s. Lows tonight will fall into the upper 40s to middle
50s.
Long Term...Thursday Night Through Wednesday
Tha main forecast concern is severe thunderstorm potential for the
western part of the forecast area Thursday evening, and
precipitation chances and amounts for the entire forecast area
Thursday night into Friday. Cooler temperatures are also
anticipated later this weekend and early next week.
The blocking upper level ridge will break down, with a negatively-
tilted short-wave moving through the western Great Lakes later
Thursday into Friday. An associated cold front will push through
the region, with PWATs increasing to near 1.5 inches along and
ahead of the boundary. The main severe threat will occur west of
the forecast area Thursday afternoon, but lingering daytime
instability and deep layer shear of 35-40 kts may allow a few
strong to marginally severe storms to impact NC/C WI during the
evening. Convection should weaken as it shifts farther east during
the overnight/Friday morning period. Probabilities are fairly
high for most of the region to receive a tenth to a quarter inch
of rain with this system, though there is a 30 percent chance of
a half inch or more in NC/C WI. Most of the rain will be east of
the forecast area by midday Friday. Generally dry conditions are
anticipated Friday night into Saturday, but another frontal
boundary could bring a chance of showers or storms Saturday night
into Sunday.
As was mentioned previously, the details of the forecast become
muddled later in the weekend into next week, with low confidence
in timing/location/precipitation amounts. There is higher
confidence in temperature trends, with the much above normal
temperatures coming to an end later this weekend/early next week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1047 PM CDT Wed Sep 18 2024
A weak upper level disturbance will produce high clouds overnight.
Moist air near the lake and bay will likely produce areas of dense
ground fog at the airports immediately west of the bay and Lake
Michigan like MTW, OCQ, SUE and MNM could have dense ground fog
late tonight through 13z Thursday.
Middle and high clouds will increase Thursday, as a weak cold
front approaches from the west. Scattered showers or thunderstorms
are possible after 2100 UTC west of a EGV to ISW line. VFR conditions
are expected outside of any convective activity.
Scattered showers and thunderstorms will move across the area
Thursday night, with IFR conditions likely west of a IMT to STE
line after midnight and MVFR to the east.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/Kieckbusch
AVIATION.......RDM
Area Forecast Discussion
National Weather Service Gray ME
1023 PM EDT Wed Sep 18 2024
.SYNOPSIS...
High pressure lingers for one more day, but does begin to break
down tonight. Moisture over the southeastern states builds
north behind this high with a slight chance for showers over
southern New Hampshire by Thursday. There may be a better chance
for showers Thursday night into Friday as low pressure develops
south of New England. High pressure builds in from the north
this weekend with more seasonable temperatures and dry weather
expected.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
1020 PM Update...No big changes to the going forecast for the
balance of the night. Did back off on the coastal plain fog
though based on latest obs and guidance.
650 PM Update...Little change to the going forecast. The
question that remains is how much fog will fill in on the coast
this evening. So far webcams on the coast show very little fog
at this time. Will continue to monitor. Otherwise, pretty quiet
weather as per the recent usual.
Previously...
Current satellite imagery shows a low pressure system bringing
some cloudier conditions into southern New Hampshire and
coastal Maine. A fog bank over the Gulf of Maine is currently
moving towards the Midcoast. Recent runs of the HRRR suggest
this fog will push into the coast after sunset and then push
inland past the I-95 corridor overnight. Areas of fog over along
the coastal plain will linger into morning commute tomorrow
with some localized dense fog possible. Radiational cooling
inland is also expected to bring some fog into the Connecticut
River Valley as well.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
Areas of fog will persist along the coast through around 9 AM
before dissipating. A low tracking east south of Cape Cod will
try to bring moisture into southern NH and coastal areas. A few
isolated showers from this low may make it into portions of the
NH seacoast, York County and in Penobscot Bay. Northeasterly
flow at low-levels will help usher in cooler temperatures as
well, so tomorrow should feel noticeably cooler than today.
Tomorrow night, we near the astronomical high tide for the month.
Northeasterly flow over the Gulf of Maine might bring some
splashover and building surf could lead to beach erosion to the
NH/ME coastline south of Portland. Patchy coastal fog lingers
tomorrow evening and builds back up by Friday morning.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
12Z operational models and ensemble solutions continue to suggest
a relatively disorganized area of low pressure will remain
southeast of Nantucket Island as we begin the extended portion
of the forecast. During the period Friday through midday
Saturday, moisture will be attempting to reach southern portion
of the forecast area as moisture from off the coastline collides
with drier air over the interior. A northern and western
adjustment to the QPF has occurred since yesterday. This is more
consistent with the latest operational Canadian and European
runs but less in par with its ensemble solutions. In any case,
have raised pops across portion of the region, but still on the
low side of guidance. Despite the cloud cover, temperatures will
likely top out over 70 degrees in most locations.
Models also remain in relatively good agreement that this system
will begin to exit out to sea late Saturday allowing Canadian
High pressure over the Maritimes to retrograde back into our
region. This will allow for drying with any leftover showers
beginning to dry up by Saturday evening.
The Canadian High will allow for dry and seasonable conditions
Sunday and Monday across the Northeast. Temperatures will be
near normal for this time of the year.
The next chance for significant precipitation will hold off
until Tuesday and Wednesday of next week. A complex frontal
system will enter the region from the west accompanied by a
vigorous upper level trough that will track over the Great
Lakes. Temperatures will be seasonably cool for this time of the
year.
Coastal Flooding...The onshore winds forecast for the coast on
Friday will coincide with very high astronomical tides. This
may lead to minor coastal flooding near the times of high tide
during the early morning hours Friday, but moreso and more
likely during the Friday afternoon high tide.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Short Term...
Generally VFR expected through the remainder of the day. A fog bank
moves into the coast this evening, and will bring lower CIGS and
visibility to RKD, PWM and PSM. Confidence is highest over the
Midcoast and Penobscot Bay. Marine fog should expand overnight,
reaching AUG by early tomorrow morning. Valley fog along the CT
River Valley will bring LIFR conditions at LEB and HIE. Fog
should mix out by 10am tomorrow. Conditions improve to VFR
during the day Thursday. Low pressure spreads low clouds into
southern and coastal areas Thursday night that could bring
restrictions.
Long Term...VFR likely prevails during the day time late
Saturday and Sunday with MVFR conditions possible in scattered
showers Friday into Saturday. Night time valley fog will bring
the potential for IFR/LIFR most nights at KLEB and KHIE. Onshore
flow and increasing clouds from a system passing south of New
England will also bring the potential for cigs around MVFR
thresholds Thursday night and possibly into Friday.
&&
.MARINE...
Short Term...
Light and variable winds this afternoon with 2-4ft seas expected
this evening. A low will slowly move well offshore from the Gulf of
Maine and could bring some unsettled weather to the open waters
tomorrow. The low will also shift winds northeasterly with
sustained 15-20kts and gusts around 25 kts Thursday night. Seas
will also increase to 3-5 feet Thursday night with SCAs likely
needed late Thursday night into Friday morning.
Long Term...Low pressure passing south of the Gulf of
Maine will bring seas building to 5 ft by Friday with continued
NE flow with gusts around 25 kts, reaching SCA criteria. Seas
remain elevated around 5 feet into the weekend with NE winds
subsiding from their peak on Friday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
SYNOPSIS...
NEAR TERM...Ekster/Palmer/Schroeter
SHORT TERM...Palmer/Schroeter
LONG TERM...Cannon
AVIATION...
MARINE...
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
801 PM CDT Wed Sep 18 2024
.KEY MESSAGES...
- A few more days of high temperatures close to 90 degrees are on
tap, which is about 10 degrees above normal for this time of
year.
- Chances of decent amounts of rain are highest early next week,
especially across the Illinois River valley, though not enough
to significantly impact the drought.
&&
.UPDATE...
Issued at 800 PM CDT Wed Sep 18 2024
High pressure is centered over the Great Lakes with ridging
extending back across much of the Midwest including central
Illinois. This will result in fair weather conditions and light
and variable or calm winds overnight. Some cirrus clouds will
pass through the region overnight, which along with the dry dew
points currently in the 50s, should stave off any fog threat
tonight.
Deubelbeiss
&&
.SHORT TERM... (Through Friday)
Issued at 300 PM CDT Wed Sep 18 2024
Scattered high clouds continue to spread eastward across the
forecast area this afternoon, with most of the diurnal type
development off to the west. 250 mb humidity plot off the RAP
model suggests a period of mostly cloudy conditions west of I-55
this evening, though cirrus thins out as it gets further into
eastern Illinois. Behind it, another period of mostly clear skies
is expected for much of Thursday.
Not a lot of change with the first cold front that moves through
Thursday night and Friday. Forecast soundings remain on the drier
side below 7000 feet ahead of the front Thursday evening, and
several of the synoptic and high-res models show a significant
weakening of the rain after it crosses the Iowa border after
midnight. Will keep a mention of likely PoP`s across the far
northwest CWA, with rain chances quickly dropping off eastward,
but still around 30% as far east as Decatur late night.
Still a couple more very warm days ahead, with highs Thursday and
Friday again in the upper 80s to around 90 degrees.
Geelhart
.LONG TERM... (Saturday through Next Wednesday)
Issued at 300 PM CDT Wed Sep 18 2024
Morning models continue to advertise that the persistent blocking
pattern will begin to break down this weekend. The remnant low off
to our east makes it about as far as the New England coast before
drifting south again, but this should allow the upper ridge to
break down as the low currently off the California coast swings
through the 4-corners region. The earlier cold front never truly
gets through the mid-Mississippi Valley, and will drift back
northward this weekend as the low weakens somewhat and moves into
the Plains. Most of the rain activity with this system appears to
be in the Saturday night into Monday time frame. The European
model is on the slower end of the guidance, with several of its
ensemble members lingering rain through Monday night, and even
keeps showers into mid week as a sprawling upper low forms over
the central Plains. Both the GFS and Canadian models are more
progressive and develop the midweek upper low more over Minnesota
or the Lake Superior region, but also with a potential tropical
system over the Gulf of Mexico which could complicate things. For
now, the Tuesday/Wednesday period will largely be with "silent 20"
PoP`s. In terms of amounts, time-lagged LREF ensembles show
precipitable water values peaking around 1.5-1.6 inches Sunday
afternoon, a little above the 90th percentile in climatology for
the first day of autumn. Probabilities of 24-hour rainfall over 1
inch remain in the 25% range across the Illinois River valley off
both the NBM and the time-lagged LREF. With the hard ground, the
gradual amounts would be more favorable for soaking in, though
more rainfall would be useful.
Geelhart
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 634 PM CDT Wed Sep 18 2024
Ridge of high pressure over central Illinois today will shift to
near the IL/IN state line Thursday. Light and variable winds will
be replaced by light southerly winds along and west of I-55 midday
Thursday. VFR conditions are expected through the period.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service New York NY
1024 PM EDT Wed Sep 18 2024
.SYNOPSIS...
Low pressure approaches from the south tonight and lingers
offshore through Saturday. High pressure builds in from the
northeast Sunday through Tuesday.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Based on radar trends and latest guidance, mainly HRRR, have
further lowered and adjusted the areal extent of rain chances
into late tonight. 18Z NAM12 and latest HRRR really just graze
eastern LI and SE CT.
Otherwise, developing low pressure approaches the region from
the south tonight. As a low level jet ahead of the low center
and enhanced moisture convergence at 850mb push in, expect rain
to move in across eastern LI and SE CT. However, noted trend
above in latest guidance will be watched closely as the area
will be on the NW periphery of the system.
There`s still a chance of some rain for most other locations.
PWATs increase to 1.75-2.00 inches, but convection will be
lacking, however there`s enough mid level forcing to tap into
this moist airmass. Anticipating only the potential of
minor/nuisance flooding which would occur late at night and
would more likely occur over eastern LI or SE CT. See the
hydrology section below for more details.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
The coastal low lingers about 50-100 miles south of eastern Long
Island through at least Thursday night as a closed 500mb low
remains nearby. The surface low may then get nudged south and
east Friday night by high pressure attempting to build in from
SE Canada.
Once again, generally higher chances of rain over eastern zones
during Thursday where the deeper moisture and stronger
forcing/convergence remain. Slight chance to chance PoPs for most
other locations. The overall threat for rain then diminishes a
little during Thursday night, but increase back a little on Friday
with a wobble in the low pressure system - bringing back better
moisture and lift. Chances drop off again Friday night as the low
nudges south and east. It will be breezy mainly at the coast during
the short term, with N to NE winds gusting 25-30 mph. Temperatures
through the period are a blend of the previous forecast and 50th
percentile NBM, both of which are cooler than the deterministic
NBM.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
**Key Points**
*Improving conditions Saturday into Sunday as high pressure builds
into the region.
*Downward temperature trend to slightly below normal temperatures
expected by early next week.
Global guidance continues to depict the slow moving upper low/trough
situated over New England to start the period. There are varying
degrees of eastward progression on Saturday, though there is
consensus that heights will begin to rise as the low moves east by
Saturday afternoon. Thus, expecting a cloudy, and windy, Saturday
with perhaps some lingering showers though Saturday evening,
especially for eastern Long Island and southeastern CT. Northeast
winds will begin to relax by Sunday afternoon as the low departs and
the pressure gradient weakens.
Thereafter, upper ridging begins to build in with surface high
pressure nosing in from the north. Dry conditions are generally
expected Sunday through Wednesday. A slightly cooler airmass advects
into the area for Monday and Tuesday under easterly flow and highs
in the upper 60s and low 70s. The airmass begins to moderate
somewhat on Wednesday, though still below normal in the low 70.
The NBM with some minor adjustments for Sunday was followed closely
for this update.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Low pressure remains offshore, southeast of Long Island,
through Thursday.
VFR. There is a chance of MVFR late during the overnight, and
toward Thursday morning, with the best chance at KGON, and
possibly into KBDR and KISP. Less confident that MVFR develops
into the NYC metro terminals. However, overall confidence
remains low, and there is uncertainty with respect to
precipitation, and how far north and west showers will be. There
is a chance that the NYC terminals and west remain dry at least
through the overnight. With the uncertainty have maintained
PROB30s, except KISP and KGON. Chances for showers remain
Thursday, with the better chances to the east.
Higher confidence with the winds. Winds remain NE to N
increasing overnight, especially at the coast terminals, then
winds increase during the day Thursday with gusts 20-25kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
There is a chance of MVFR at KLGA and KJFK as patchy stratus
moves through the region. Better chances will be with any
precipitation overnight. And confidence remains low on
timing and chances for MVFR.
OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
Thursday night through Friday: Periods of rain/showers possible
with with MVFR or lower conditions. NE-N gusts 20-25kt.
Saturday: Slight chance of showers. VFR NYC terminals and west,
possibly MVFR. MVFR east of the NYC terminals, VFR possible
during the afternoon. NE gusts around 25kt possible.
Sunday: VFR. NE gusts 20-25kt possible.
Monday...VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
SCA has been extended on all waters through Thursday night and will
likely need to be extended at least on the ocean waters through this
weekend as an offshore low keeps winds and seas elevated. Gusts on
the ocean could reach 30 kt this weekend. For the non-ocean waters,
might need to extend the SCA into Friday, but will probably not be
needed thereafter.
&&
.HYDROLOGY...
Cannot rule out the possibility of minor poor drainage flooding late
tonight into Thursday mainly over eastern LI and SE CT. There is now
fewer guidance suggesting the potential of moderate to heavy
rainfall, so flash flooding is not a concern at this point. Will
still need to watch model trends in rainfall amounts and the track
of the storm as the ingredients for a rainfall heavier than
currently forecast are still present. HREF probabilities of an inch
of rain in an hour are up to 30-40% not too far offshore. Expecting
a total rainfall of up to an inch and a half for these areas through
Friday, however most of this would likely fall late tonight into
Thursday morning. For the rest of the Tri-State area, no impacts
expected with rainfall amounts likely under a half of an inch.
There are no hydrologic issues for Friday through the middle of next
week.
&&
.TIDES/COASTAL FLOODING...
Coastal flood advisories have been expanded to include SW CT
tonight in addition to the one already in effect for southern
Queens and Nassau. A statement remains up for areas adjacent to
NY Harbor. Advisories were then expanded for the Thursday
morning/early afternoon high tide cycle to include locations
adjacent to NY Harbor, western LI Sound, and the south shore
back bays of LI. A statement is in effect for eastern LI and and
New Haven county CT. Advisories will then continue for the
south shore bays and portions of western LI Sound for Thursday
night.
The combination of high astronomical spring tides and deepening
low pressure over the western Atlantic will result in several
rounds of mainly minor coastal flooding over the next couple of
days. Localized moderate coastal flooding is possible for
souther Nassau and SW Suffolk, especially Thursday morning. In
addition, as the low slowly pulls away over the weekend, tidal
piling from a long period easterly swell will continue although
astronomical tides will be gradually coming down. Thus, the
potential is there for continued minor coastal flooding into the
weekend, especially across the south shore bays of western LI
and the SW CT coast.
A high rip current risk continues through Friday for the ocean
beaches due to building E/NE swells and gusty N-NE winds. Seas
on the oceanfront will build to up around 6 ft. However, a high
surf advisory has not been issued as seas are forecast to stay
below criteria of 7 ft. Minor beach erosion is expected, but any
dune issues should be isolated.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory until 2 AM EDT Thursday for CTZ009.
Coastal Flood Advisory from 10 AM to 2 PM EDT Thursday for
CTZ009.
Coastal Flood Advisory from midnight Thursday night to 3 AM
EDT Friday for CTZ009.
NY...Coastal Flood Advisory until 2 AM EDT Thursday for NYZ071.
Coastal Flood Advisory from 10 AM to 2 PM EDT Thursday for
NYZ071-073-078-177.
Coastal Flood Advisory from midnight Thursday night to 3 AM
EDT Friday for NYZ071.
Coastal Flood Advisory from 8 AM to 11 AM EDT Thursday for
NYZ072-074-075.
Coastal Flood Advisory from 8 PM to 11 PM EDT Thursday for
NYZ074-075.
High Risk for Rip Currents through Friday evening for NYZ075-080-
081-178-179.
Coastal Flood Advisory from 9 AM to 2 PM EDT Thursday for
NYZ080.
Coastal Flood Advisory from 8 PM Thursday to 2 AM EDT Friday
for NYZ080-178-179.
Coastal Flood Advisory until 11 PM EDT this evening for NYZ178-
179.
Coastal Flood Advisory from 8 AM to noon EDT Thursday for
NYZ178-179.
NJ...Coastal Flood Advisory from 8 AM to 11 AM EDT Thursday for
NJZ006-106-108.
Coastal Flood Advisory from 8 PM to 11 PM EDT Thursday for
NJZ006-106-108.
MARINE...Small Craft Advisory from 6 AM Thursday to 6 AM EDT Friday for
ANZ331-332-335-338-340-345.
Small Craft Advisory until 6 AM EDT Friday for ANZ350-353-355.
&&
$$
SYNOPSIS...JC/DBR
NEAR TERM...JC/MET/DW
SHORT TERM...JC
LONG TERM...DBR
AVIATION...MET
MARINE...JC/DBR
HYDROLOGY...JC/DBR
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Norman OK
1043 PM CDT Wed Sep 18 2024
...New AVIATION...
.KEY MESSAGES...
Updated at 1041 PM CDT Wed Sep 18 2024
- Isolated to scattered thunderstorms in northern and western
Oklahoma this evening, with scattered thunderstorms possible
from northern to central Oklahoma tomorrow evening.
- Hot/humid conditions on Thursday and Friday.
- Heat relief looking probable by the weekend.
&&
.SHORT TERM...
(This evening through Thursday)
Issued at 310 PM CDT Wed Sep 18 2024
Cumulus has begun to develop in northwestern Oklahoma, and there
remains some signal in both synoptic models and CAMs of seeing
convection development across northwestern and western Oklahoma
late this afternoon or this evening near an area of confluence in
the low-level wind field. Forcing is not terribly strong and
expected any development to be isolated or scattered. There is an
axis of higher instability from west central Texas up into far
northwestern Oklahoma with CAPE above 1000 J/kg per SPC
mesoanalysis and short-term RAP forecast, so an isolated strong or
severe storm will be possible, and SPC`s marginal risk area
highlights the potential area well... but do currently think that
severe potential will be isolated. Although many of the showers
and storms will likely dissipate by mid-late evening, there is
still enough QPF signal in some models overnight and into Thursday
morning to keep some low POPs in the forecast. But scattered
storms are expected to develop again Thursday afternoon near and
ahead of a front moving into the area.
Winds veer ahead of this front Thursday proving a more downslope
flow and warmer temperatures. And even though a front pushes into
northwest Oklahoma on Thursday, the arrival is late enough it
won`t provide relief from the warm expected temperatures on
Thursday.
&&
.LONG TERM...
(Thursday night through next Tuesday)
Issued at 310 PM CDT Wed Sep 18 2024
Thursday`s front washes out and still does not provide any
significant cooling for the area, so warm weather will continue
Friday and Saturday. A western U.S. trough is still expected to
eject toward the Plains this weekend, but the trend continues to
slow this system and related precipitation for our forecast area -
more toward Saturday night and Sunday. The forecast continues to
carry 30%+ POPs north and 20% POPs south, but the highest QPF
signal is north of the forecast area given the projected track of
the storm system. This system does help push a front south through
the forecast area Sunday and Sunday night bringing cooler weather
back into the area.
&&
.AVIATION...
(06Z TAFS)
Issued at 1041 PM CDT Wed Sep 18 2024
VFR will be forecast through the period, outside of restrictions
associated with scattered TSRA across northern and central
Oklahoma after 21Z. Otherwise, light to moderate southerly winds
ahead of a cold front that is progd to stall near the Kansas
border before lifting back to the north after this forecast valid
period.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 73 96 74 98 / 20 30 30 0
Hobart OK 74 100 74 100 / 20 20 20 0
Wichita Falls TX 75 100 74 101 / 10 20 10 0
Gage OK 70 99 68 100 / 20 10 0 0
Ponca City OK 72 99 70 98 / 20 30 30 0
Durant OK 71 97 72 98 / 0 10 20 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...26
LONG TERM....26
AVIATION...11