Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/26/23
Area Forecast Discussion
National Weather Service Amarillo TX
634 PM CDT Fri Aug 25 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Saturday night)
Issued at 231 PM CDT Fri Aug 25 2023
A glimmer of hope to get some precipitation in the next 36 hours
still holds for the western Panhandles, but quickly drops off in the
central and eastern Panhandles. An upper level trough currently
tracking from the Dakotas to the Great Lakes region, has a trailing
cold front expected to expand south across our area this evening. As
that front approaches the Panhandles there`s enough moisture and
lift associated that we can expect some showers/storms to develop.
This will be mainly in the northwest and likely after 6PM. But with
the loss of daytime heating the rest of the Panhandles southeast of
the Dalhart to Guymon line, may not see anything. The cold front
may be strong enough to impact the high temperatures across the
north for tomorrow. Have gone a bit more agressive than NBM with
cooler highs tomorrow in the upper 70s to the north and upper 80 to
the south.
As that system exits east tomorrow, the front will slowly retreat
back north and warmer temperatures will return for the end of the
weekend. As far as Saturday afternoon goes, we`ll still have a
retreating front and possibly a boundary that will trigger some
storms. But the higher resolution models are not very bullish on
rain chances here in the Panhandles. There will be moisture, it`s
still up in the air as to if the moisture is more around the outer
edges of the forecast area or if we`ll get lucky enough to get some
showers/storms over the central Panhandles. There is a shortwave
progged to move through on Saturday night but the high res guidances
are not very excited about our chances. The HRRR high res guidance
has suggested a possible round of showers and storms for Deaf Smith
County tomorrow night, but there is not much consistency in this
with other hi res models. The ridge will continue to build over
the Four Corners region and transition us to northwest flow as we
move into the extended.
Weber
&&
.LONG TERM ...
(Sunday through next Thursday)
Issued at 231 PM CDT Fri Aug 25 2023
Rain chances continue to look rather promising for parts of the
area to cap off the weekend and kick off the work week. However,
doubts still exist on the placement and coverage of best rainfall.
Model agreement is still strong that the western portions of the
Panhandles are most favored through Monday night, but latest
indications have been trending even further west than before,
potentially not looking as good for the central Panhandles and
areas eastward. Daytime highs will be closer to seasonal averages
in the 80s through Wednesday before warming back into the 90s
later in the week.
Some lingering showers from overnight activity will still be in
place Sunday morning, but should clear out and push south by the
afternoon. As the 500mb ridge continues its westward retreat,
locations on the periphery of its core could see another
disturbance move through and act as the focus for our next round
of rain/storm development. Availability of deep layer moisture
won`t be an issue, with PWATs around 1.50" and higher dew pts in
the 60s still being forecast. If the ridge sets up too far west
though, it could take the better upper level support with it,
failing to utilize favorable ingredients to its east. Whereas
prior model runs moved a wider swath of precip across much of the
Panhandles Sunday night into Monday, majority of 12z guidance is
keeping the bulk of activity closer to the NM-TX border. Since
coming into range, the NAM has consistently been holding onto this
drier solution for Sunday night as a possibility. And
unfortunately, now other deterministic models appear to be
following suit. For this reason, have decided to lower NBM POPs
from Sunday afternoon through Monday morning. The good news is
that for now, much of the area still has a 40-70% probability to
pick up some decent accumulations (a couple tenths of an inch by
Tuesday). If Sunday-Sunday Night`s system fails to bring you any
rain, there could be another disturbance moving through late
Monday into Monday night to pick up the slack. But once again,
the western half of the combined Panhandles still look to have the
better shot.
NW flow aloft decreases as we go through next week and large
scale subsidence returns. With fuels continuing to become more
stressed in the south, any areas that fail to receive appreciable
rainfall may need to be monitored for potential elevated fire
weather conditions, especially on any days of increased winds.
Harrel
&&
.AVIATION...
(00Z TAFS)
Issued at 617 PM CDT Fri Aug 25 2023
As of this evening radar and satellite continue to display storms
moving across the northwestern portion of the Panhandles.
However, latest storm motion should keep impacts to the terminals
to a minimum with currently KGUY having vicinity showers active.
KDHT could see impacts later tonight as CAMs depict storms pushing
in sometime after midnight. Have kept mention of potential in
current package, but confidence in impacts continue to wane given
that current showers not matching up to pervious runs. Otherwise,
all terminals are expected to deal with wind gusts through the
overnight but should keep to VFR conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 67 89 66 88 / 10 20 30 40
Beaver OK 67 83 63 83 / 20 20 50 30
Boise City OK 63 78 61 82 / 60 40 50 40
Borger TX 70 90 68 90 / 10 20 40 30
Boys Ranch TX 67 88 66 89 / 10 20 40 40
Canyon TX 67 90 65 88 / 10 10 30 30
Clarendon TX 72 93 71 88 / 0 10 30 30
Dalhart TX 63 81 61 84 / 30 30 40 40
Guymon OK 64 79 62 83 / 30 30 50 30
Hereford TX 66 91 66 90 / 10 10 30 30
Lipscomb TX 67 88 64 85 / 10 20 40 40
Pampa TX 68 87 66 85 / 10 20 40 30
Shamrock TX 70 92 69 88 / 0 10 30 30
Wellington TX 72 96 71 91 / 0 10 30 30
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&
$$
SHORT TERM...89
LONG TERM....38
AVIATION...11
Area Forecast Discussion
National Weather Service Boston/Norton MA
943 PM EDT Fri Aug 25 2023
.SYNOPSIS...
Scattered showers, mist and drizzle tonight, with wet weather
lingering into Saturday morning along the south coast. Not out
of the question there are a few thunderstorms as well Saturday.
Partly sunny for much of Saturday for most with perhaps an
isolated shower or storm during the afternoon. Dry and
seasonable Sunday and Monday, before shower chances return for
Monday night into Wednesday morning. Then another stretch of
dry, pleasant weather arrives later Wednesday and continues into
Friday. Distant tropical storm Franklin could bring rough surf
and strong rip currents mid to late next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
10 PM Update...
Shower activity north and west of the I-95 corridor between
Boston and southern Rhode Island has become increasingly
scarce, though drizzle has developed given low level saturation
up to 900mb.
Conversely, as modeled well by the CAMs, showers have begun to
rebound in intensity across far SE MA and the Cape and Islands.
To account for trends, significantly cut PoPs across the
interior and added drizzle to the forecast for areas where the
chance of rain was less than 40%. While not yet in, the 00Z HREF
Ensemble looks to be key to evaluating shower potential across
the interior overnight and into the first half of Saturday
morning.
7 PM...
Deep layer moisture is moving offshore, so steady rains from
this afternoon will transition to mist/drizzle from west to east
this evening. Given the high dew pt airmass (65-70), it will be
mild night, along with patchy fog. Previous forecast captures
these details, thus no wholesale changes to the forecast.
Earlier discussion below.
-----------------------------------------------------------------
Highlights
* Isolated to scattered showers this evening. Activity becomes more
numerous late tonight into Sat, especially across RI/SE MA where
there may be some thunderstorms. Low shot of a strong thunderstorm
or two.
Quasi zonal flow in place late this afternoon and through much of
Sat. A shortwave is lifting offshore late today, while a deeper
trough digs into the central Great Lakes from northern MN. The
trough digs into the eastern Great Lakes by Sat AM and lifts into
northern New England on Sat. Low pressure lifts into northern New
England tonight along with the warm front, while the trailing cold
front slides in from the west. The front should move through much of
southern New England by mid/late Sat AM, but may stall over portions
of the south coast for later on Sat.
Unsettled through much of this timeframe. Main concern in the
forecast is the resurgence of showers along with some thunderstorm
activity as the cold front crosses the region late tonight into Sat.
Should have a relative lull in activity this evening as there is
weak mid level ridging and height rises before the trough digs into
the eastern Great Lakes late. Will also see PWATs lower to roughly 1-
1.5" across the interior, but still stay around 1.5-2"+ across the
south coast into eastern MA. Tried best to capture this utilizing
the latest HREF guidance and in particular the ARW/FV3, which are
handling the current situation quite well. The question across the
interior will be with the column drying out how widespread will
activity be? Think that isolate the scattered chances cover the risk
well overnight, while across eastern areas we should be a bit more
widespread given the PWATs and a roughly 20-40 kt SW low level jet
moving offshore nearby. Could perhaps see some isolated thunder
tonight, but especially toward daybreak as MUCAPE values increases
to roughly a few hundred to around 1000 J/kg as the cold front
slides in.
On Saturday think that the cold front should be through most of
southern New England other than RI and eastern MA. Think that along
this frontal boundary there is the potential for a strong
thunderstorm or two. Will see MUCAPE values maximize around a few
hundred to roughly 1500 J/kg, with the highest values over RI/SE MA.
This overlaps with deep layer shear in the 0-6 km layer of 30-50 kts
as the trough is lifting into our area during the AM. Appears that
we lose the deeper layer shear during the afternoon as the trough
lifts further into northern New England. Think the question may be
how much we are able to clear out/destabilize across RI/SE MA.
Expect low level lapse rates around 5-7 degrees Celsius and 5-6
degree mid level lapse rates. Do have some low probs (10-30 percent)
of UH within the 2-5 km layer greater than 75 units per the latest
HREF across SE MA. Not out of the question the risk is a bit further
west, but will largely be dependent on the cold fronts location.
Areas further inland could perhaps see some isolated/scattered
showers or a storm, but will be fighting the column drying. This
should limit shower/storm coverage. At this point appears that the
greatest risk with any stronger storms is gusty winds and small
hail. Not seeing any severe signal via the NCAR HRRR Neural Network
Convective Hazards, but still have some low probs via the CSU ML
Severe risk. Will be something we need to keep an eye on especially
earlier on Sat when there is more overlap between the CAPE/shear.
Think that much of the region will see the sun break out on Sat,
other than perhaps the Cape/Islands. Given the northwesterly flow in
wake of the cold front opted to bump temps up to the 75 percentile
of guidance to account for downsloping. The result are comfortable
highs ranging from the mid 70s to the mid 80s. Best shot for low/mid
80 degree readings is across the CT and Merrimack Valley.
&&
.SHORT TERM /SATURDAY NIGHT/...
Highlights
* Any showers tapering off during the evening with skies clearing.
Cloud cover increasing late especially across eastern areas.
Stuck under cyclonic flow through this period. High pressure will
begin to nudge into our region from the west/northwest.
Should see any lingering showers and perhaps a thunderstorm or two
tapering off during the evening as the cold front slides offshore.
Column continues to dry with W/WNW flow aloft bringing our PWATs
below 1 inch late. This will result in cloud cover decreasing for
much of the region during the evening. Do think we may see some
stratus advecting in from the NE across the eastern half of the CWA,
which is shown well by the increase in RH within the 1000-850 hPa
layer and via the HREF. Otherwise should be a dry, and quiet night.
These clouds should keep temps a bit warmer across eastern areas.
Lows bottom out in the low/mid 60s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
345 PM update...
Highlights:
* Taste of Autumn with mild days (70s) and cool nights (50s),
especially late next week
* Mainly dry Sunday into the daylight hours of Monday, followed by
showers and possible thunderstorms Monday night into Tuesday night
* TS Franklin likely tracks out to sea, but rough surf & strong rip
currents possible for MA/RI beaches mid to late next week
Sunday...
Dry NW flow with seasonable temps aloft, but may overachieve a bit
given downslope flow. Although, it will be turning more comfortable
given the NW flow and good column drying as PWATs slowly fall thru
the day. A real nice day, with a mix of sun and clouds, highs 75-
80, dew pts 55-60 and a light NNE wind.
Monday...
Mainly dry weather should prevail, but have to watch a short wave
trough ejecting ENE out of the OH Valley/eastern Great Lakes. This
could trigger a few late day showers/storms over western MA/CT.
Otherwise, dry weather should prevail. Highs in the 70s. Becoming
more humid than Sunday, with dew pts rising from the 50s into the
60s Monday. With high pressure overhead, light onshore winds
expected.
Monday night thru Tuesday night...
Becoming warmer and more humid with noticeably moisture return from
the south, with PWATs peaking about 150% of normal Tue night per
ensembles. Not raining every hour of this forecast period, but
definitely potential for some downpours, with potential frontal wave
tracking along/near the south coast.
Wednesday...
High amplitude trough approaches Wed AM with showers/storms likely
around 12z, then dry slot overspreads the region in the afternoon
along with westerly flow, supporting an improving trend per
ensembles from west to east. Warm start to the day combined with
increasing westerly flow, temps may overachieve a bit with highs 75-
80. This trough will also kick TS Franklin seaward, precluding a
direct impact on SNE. However Wed and Thu there could be rough surf
and strong rips for S-SE facing ocean beaches of RI/MA.
Wednesday night into Friday...
Drier and noticeably cooler behind exiting trough. PWATs plummet to
about 50% of normal. At the surface this will translate to dew pts
falling into the 50s, possibly 40s Thu night, supporting a very cool
night. Highs Thursday may only top out in the upper 60s across the
high terrain, and this is with partial sunshine. Low 70s elsewhere
and rebounding to 70-75 Friday.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
23z update...Moderate confidence.
Steady rains from this afternoon transition to more of a
mist/drizzle this evening. Patchy fog as well. TAFs overnight
look good, so no wholesale changes expected. Earlier discussion
below.
------------------------------------------------------------------
Tonight...Moderate confidence.
IFR to LIFR conditions gradually improving to MVFR toward
daybreak across the interior. Will see an uptick in hit/miss
showers for much of the region, but best shot is across the
south coast and especially the Cape/Islands. It is across the
south coast/Cape and Islands where there could be some thunder
heading into, but especially around/after the AM push. S winds
at 5-15 kts shifting to the SW/W late across the interior as a
cold front crosses through. Could have some 20-30 kt gusts
across the Cape.
Saturday...High confidence in trends, but moderate in exact
timing.
MVFR to IFR conditions gradually improving to VFR from west to
east. Taking the longest across the Cape/Islands where there
will be scattered showers and thunderstorms especially before
18Z. Improvement to VFR across the interior roughly 15-18Z and
closer to 21-00Z for the Cape/Islands. Winds shift to the NW/W
for most less than 10 kts. The Cape/Islands may stay SW/S for
much of the day with gusts of 20-25 kts during the AM. Locally
higher gusts if a t-storm moves through a terminal.
Saturday Night...High confidence.
VFR with NW to N winds around 5-10 kts. Low prob that MVFR/IFR
ceilings push into eastern terminals as we see a surge of NE
flow.
KBOS TAF...Moderate confidence.
IFR through the day with spotty rain showers. Could briefly see
visibilities falling to IFR/LIFR in any heavier showers with S
winds 10-15 kts and gusts 20-25 kts. IFR persists tonight with
perhaps another slug of scattered showers toward the AM push Sat
with the cold front sliding in/through. Winds shift to the SW/W
late. Could have some thunder, but risk greater to the SE. May
be needed in future TAF updates. Improving to VFR by mid/late
Sat AM and winds shift to the NW/N around 5-10 kts.
KBDL TAF...Moderate confidence.
IFR conditions through the day with southerly winds at 5-10 kts.
Activity more spotty late this afternoon into tonight, but could
have potential for some fog overnight. Should see any fog lift
Sat AM and improve to VFR by roughly 12-15Z. Winds shifting to
the SW toward Sat AM push and W/NW by mid/late Sat AM with a
cold front passage.
Outlook /Sunday through Wednesday/...
Monday: VFR.
Monday Night: VFR. Slight chance SHRA.
Tuesday: Mainly VFR, with local MVFR possible. Chance SHRA.
Tuesday Night: Mainly VFR, with local IFR possible. Chance
SHRA.
Wednesday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA.
Wednesday Night: VFR. Breezy. Slight chance SHRA.
Thursday: Breezy.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight...High confidence.
Widespread rain showers becoming scattered this evening. Will
see renewed uptick in activity late tonight into early Sat.
Think the vast majority of the time will be showers, but there
may be some thunderstorms especially late tonight and heading
int Sat AM. Winds out of the S/SSW at 10-20 kts with gusts of
20-30 kts. Seas 4-7 ft across the outer waters and 3-5 ft across
the RI/Block Island Sounds. Please see the Small Craft
Advisories for more detailed information.
Saturday...High confidence.
Scattered rain showers and thunderstorms across the waters for
much of the day. Risk greatest especially near the Cape/Islands
and eastward. Winds out of the S 10-20 kts initially with gusts
of 15-25 kts easing as the day goes on. Will see winds abruptly
shift in wake of the cold front late in the AM/early afternoon,
but speeds should be around 5-10 kts. Seas 1-4 ft across the
interior waters and 3-5 ft for the outer waters. Small Craft
Advisories still in effect for portions of the region, please
see that product for more details.
Saturday Night...High confidence.
Any lingering shower/storms come to an end. Winds shift to the
NW/N and eventually the NNE toward daybreak Sun. Should see
speeds of 5-10 kts most of the night, but increase toward 10-15
kts toward daybreak. Seas 1-4 ft.
Outlook /Sunday through Wednesday/...
Monday: Winds less than 25 kt. Slight chance of rain showers.
Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain showers.
Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Chance of rain showers.
Tuesday Night: Winds less than 25 kt. Areas of rough seas.
Chance of rain showers.
Wednesday: Winds less than 25 kt. Local rough seas. Chance of
rain showers.
Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain
showers.
Thursday: Winds less than 25 kt. Seas up to 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Saturday for ANZ231.
Small Craft Advisory until 11 AM EDT Saturday for ANZ232>234.
Small Craft Advisory until 2 PM EDT Saturday for ANZ235-237.
Small Craft Advisory until 8 PM EDT Saturday for ANZ250-
254>256.
&&
$$
SYNOPSIS...Nocera/BL
NEAR TERM...BL/KS
SHORT TERM...BL
LONG TERM...Nocera
AVIATION...Nocera/BL
MARINE...Nocera/BL
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
631 PM CDT Fri Aug 25 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Saturday night)
Issued at 303 PM CDT Fri Aug 25 2023
Satellite imagery (via clouds) depicts a mid to upper cyclonic
circulation over the West Gulf moving west into Northeast Mexico. A
feeder band is approaching and moving into the Lower Texas Coastal
Waters. The moisture associated with this feature helped push the
morning sounding PWAT at BRO to over two inches. Extant convection
is mainly over the adjacent Gulf waters, but additional convection
is developing off the sea breeze in Northeast Mexico. Aside from the
aforementioned feature, mid-level ridging centered over North Texas
remains strong, and will shift slowly west in the short term, but
will have a lesser impact on the region than the transiting upper
feature. The HRRR shows most of the near term convection (through
tonight) avoiding the CWA, but a few showers may make it into
Cameron County from the Gulf later this afternoon through early
Saturday morning.
Skies will remain partly cloudy tonight with low temps in the mid
70s, close to seasonal norms. The mix of clouds will continue
Saturday and Saturday night with initially light to moderate
northeast to east winds slowly veering to southeast by the end of
the short term. Saturday will see slightly warmer than normal
temperatures, in the upper 90s to slightly above the century mark.
That means heat index values in the 103 to 108 degree range.
Convection will increase Saturday during the day, with coverage
likely starting around mid-morning near the coast, then pushing west
across the mid valley and into the upper valley and RGV Plains late
in the afternoon. A few rumbles of thunder will be possible with the
CWA in a general thunderstorm outlook area on Saturday. The
Ranchlands will will likely see lower rainfall chances, however,
being farther north from the main axis of instability. The best rain
chances will occur across southern Cameron and Hidalgo Counties
Saturday afternoon. Though forecast QPF amounts are not too large,
only a couple of tenths of an inch, that does not mean there
couldn`t be a few locally heavier downpours generating slightly
higher rainfall amounts.
Rip current risk will drop from moderate to low tonight as swell
period shortens and seas remain low.
&&
.LONG TERM...
(Sunday through next Friday)
Issued at 303 PM CDT Fri Aug 25 2023
The upper level ridge
that has been the dominate feature this summer will be centered over
Arizona/New Mexico by Sunday. On Tuesday, the an upper level trough
will move into the ArkLaTex region, providing some synoptic scale
forcing to central and southern Texas. A weak cold front associated
with this system is forecast to move into Deep South Texas on
Tuesday before stalling. This should bring higher POPs on Tuesday
and Wednesday. The guidance has this trough remaining in place for
the remainder of the week while the ridge builds back over West
Texas. Drier mid level flow on the back side of this trough should
keep POPs near zero for Thursday and Friday. The high temperatures
will likely return to triple digits Sunday through Tuesday before
the weak cold front moves through, then remain in the upper 90s
through Friday.
The National Hurricane Center is monitoring a disturbance in the NW
Caribbean for development into a tropical cyclone as it moves
northward into the eastern Gulf by early next week; current
probability of development is 80%. However, whatever ultimately
develops is highly unlikely to be any direct threat to Texas. Even
any beach and marine impacts are uncertain at this point.
&&
.AVIATION...
(00Z TAFS)
Issued at 629 PM CDT Fri Aug 25 2023
VFR should prevail at all three TAF sites through much of the
forecast period. Gusty easterly winds early this evening will
subside by or just after sunset this evening and become nearly
calm by midnight tonight. Winds become E/ENE (light-moderate) by
mid-late morning on Saturday. Spotty to scattered
showers/thunderstorms will develop again by late Saturday
morning. Convection will be hit-and-miss and chances will
continue through the afternoon hours. Ceilings and visibilities
may briefly drop to MVFR or IFR underneath any shower/thunderstorm
that pushes over the terminals.
&&
.MARINE...
Issued at 303 PM CDT Fri Aug 25 2023
Tonight through Saturday Night...Light to moderate winds and low to
moderate seas. Unsettled weather will continue in the short term,
and will be slightly more likely Saturday as a mid-level inverted
trough passes just south of the area. Isolated to scattered showers
and thunderstorms will be possible.
Sunday through next Friday...A weak pressure gradient is
forecast to keep winds relatively low for the long term period.
Isolated to scattered showers and thunderstorms are possible Tuesday
and Wednesday, otherwise favorable marine conditions should prevail.
&&
.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE 79 93 79 97 / 20 60 10 10
HARLINGEN 75 95 75 99 / 0 50 0 10
MCALLEN 77 97 77 101 / 10 50 10 10
RIO GRANDE CITY 77 98 77 101 / 20 30 10 0
SOUTH PADRE ISLAND 80 88 80 89 / 20 50 10 10
BAYVIEW/PORT ISABEL 77 93 77 95 / 10 50 0 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM...54-BHM
LONG TERM....60-BE/64-Katz
AVIATION...67-Mejia
Area Forecast Discussion
National Weather Service Green Bay WI
1054 PM CDT Fri Aug 25 2023
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Saturday
Issued at 244 PM CDT Fri Aug 25 2023
The latest RAP analysis and satellite/radar imagery show cold
front dropping southeast across western Lake Superior an about to
move into northwest Wisconsin early this afternoon. Convergence
and instability along the front with surface based instability
upwards of 1000-1500 j/kg. Deep layer shear is robust at 50-60 kts
with relatively long and straight hodographs. However, while
showers and storms have already developed and are approaching
north-central WI, they have been low topped so far with echo tops
up to 25 kft. A few gusts to 40 mph have been observed in the
surface obs already, and think 40-50 mph gusts is about what can
be expected as the storms move in to north- central WI late this
afternoon and northeast Wisconsin this evening. Forecast concerns
mainly revolve around thunderstorm potential and timing tonight
followed by cloud/wind trends on Saturday.
Tonight...A strong shortwave will rapidly push the front southeast
across the region during the evening. A narrow zone of surface
based instability will gradually dissipate as nocturnal cooling
sets in. As a result, storm intensity will be near peak or have
already peaked as isolated to scattered storms slide southeast
across northeast to central WI. Think the chance of gusty winds
will persist in the strongest storms as they weaken, though, as
high dcapes will promote gusty winds to reach the surface. Will
keep a mention of gusty winds and small hail in the HWO.
The chance of storms will depart by late evening with winds
veering to the north. The north winds will advect low stratus (currently
north of Lake Superior on satellite imagery) across the region in
low level cold advection. Moisture depth does not look deep enough
for showers or drizzle, so lowered precip chances somewhat, but
did not remove them completely. North to northeast winds will
increase late and become gusty to 25 mph over northeast WI. Lows
in the 50s to low 60s.
Saturday...Widespread low broken to overcast skies will likely be
present during the morning with a few spits possible over
northeast WI. Then incoming dry air with a surface high should
help mix out the clouds by mid to late afternoon. Temperatures
have cooled a few degrees in this forecast cycle with highs
ranging from the middle 60s to lower 70s.
.LONG TERM...Saturday Night Through Friday
Issued at 244 PM CDT Fri Aug 25 2023
High pressure overhead will provide mostly clear skies and light
winds Saturday night, with ideal radiating conditions across
northeast Wisconsin. This will allow temperatures to tumble
through Sunday morning, with lows ranging from the upper 30s to
lower 40s across the north and around 50 across east-central
Wisconsin. Some patchy frost is possible across portions of
north-central Wisconsin Saturday night and Sunday morning,
especially across the cold prone areas.
The high will slowly drift southeast through the early part of
next week, allowing temperatures to moderate a bit as temperatures
return to around normal by Monday. A slow moving cold front will
bring showers to the area Monday afternoon through Tuesday as it
tracks through the area along with some rumbles of thunder.
Thunderstorms with this cold front are not expected to be severe
given the lack of instability and shear.
High pressure will build in behind the departing front Tuesday
night, and linger across the area through Thursday. This will
bring a stretch of dry and quiet weather to the region as well as
below normal temperatures.
A weak cold front will bring the chance for showers back to the
area Thursday night into next Friday; however, the front weakens
quite a bit as it tracks through the region so it is possible it
comes through mostly dry. Warm air advection ahead of the front
will allow temperatures to return to around normal by the end of
next week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1054 PM CDT Fri Aug 25 2023
Thunderstorms have cleared out, with just a few remaining showers
in east-central Wisconsin as of 04Z/26. Expect main VFR conditions
for a few hours tonight; then, low clouds arrive from the north
resulting in IFR/MVFR cigs late tonight and throughout Saturday
morning. Patchy fog may also develop in spots, especially north,
and could lower vsbys to 3 to 5 miles. North winds will increase,
with gusts to 20 kts.
Drier air filters in Saturday afternoon which will aid in
breaking up the low clouds and improving flying conditions.
&&
.MARINE...
Issued at 244 PM CDT Fri Aug 25 2023
Gusty northeast winds behind a cold front will develop
late tonight into Saturday morning. Gusts of 20 to 25 kts and
waves up to 4 ft will be possible, peaking mid-morning to early
afternoon. Small craft are urged to use caution. A small craft
advisory may be needed.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from 7 AM CDT Saturday through Saturday
evening for WIZ040-050.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kurimski
AVIATION.......KLJ
MARINE.........MPC
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1044 PM EDT Fri Aug 25 2023
.SYNOPSIS...
Hot conditions will persist through Saturday. A cold front settles
into the region Sunday, and is expected to stall across the region
and provide a focus for locally heavy rainfall at times Sunday
through Tuesday. Temperatures should fall back to normal Sunday
with the front, then remain below normal much of next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1030 PM Friday: Well the MCS did in fact hold together as it
pushed southward. Luckily it has been weakening will progressing
south and east across eastern TN this evening. Did have to change
the location of PoPs/PoTs as the activity was originally expected to
come in from the north, but currently it is tracking in from the
west. Thus, have moved the chance PoPs/PoTs to the western NC mtns
and removed them from the NC Piedmont. The activity should push
across the NC/TN border within the 30 to 45 minutes. Already seeing
some isolated showers developed ahead of the main line of convection
in Madison County. Overall these storms have been trending downward
in strength, so the overall severe potential looks to be very low.
Still we cannot rule out the potential for an isolated strong storm
with this activity. Any strong storm that develops will have heavy
rainfall and gusty winds as the main impacts. Lows tonight will be
around 7-9 degrees above climo. Patchy mountain valley fog may
develop overnight into daybreak Saturday, especially for any
locations that receive heavy rainfall tonight.
For Saturday, the upper ridge to the west continues to expand
eastward leading to temperatures similar to what we saw today, with
temps climbing into the mid to upper 90s (~10-12 degrees above
climo). Heat indices east of the mountains are expected to reach the
lower 100s. A Heat Advisory was issued and is in place from noon to
8 PM EDT Saturday for portions of NE GA and the western SC Upstate
as these locations are most likely to see heat indices ranging from
105 to 108 degrees. A cold front will gradually track out of the
N/NW throughout Saturday leading to shower and thunderstorm
development during the afternoon and early evening hours. CAMs are
not in agreement regarding the overall coverage for convection
tomorrow afternoon. The 00Z HRRR shows widespread showers and
thunderstorms across much of the CWA, while the 00Z NAM Nest shows a
much more isolated and muted response. Given the instability and
moisture available Saturday afternoon, confidence is moderate that
at least a few scattered thunderstorms will be able to develop
across the area. Therefore, went with chance PoPs for most the area.
The Day 2 SPC Severe Wx Outlook has the entire CWA in a Marginal
Risk for isolated severe storms. Damaging winds look like the main
potential threat with any severe storms that develop. Any showers
and thunderstorms that develop may ac to limit heat indices Saturday
afternoon.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 100 PM Fri: Stalled/wavering frontal zone is the story for the
late weekend and early next week. Lift over it will be enhanced by a
weak shortwave rotating thru the upper trough late Sunday and Monday,
which also reinforces the Eastern trough regime. The NAM suggests
this development may lead to weak cyclogenesis along the boundary in
the GA/SC vicinity. Regardless, low to midlevel flow will turn more
southerly preceding the shortwave and that will aid in moisture flux.
PWATs will remain elevated invof the boundary, but as a result of
that flux appear likely to exceed 2 inches in the Piedmont. Coupled
with the opportunity for more frequent precip development, this
suggests a gradual uptick in the threat of flooding. This prompted
WPC to place a Slight Risk in our area for Day 4 (Mon-Tue morning),
but the actual scale of the risk likely will depend on how much the
rainfall in the preceding days saturates area soils.
A shallow layer of northerly CAA associated with high pressure over
the eastern Great Lakes will continue thru the period; this will
provide some relief from the heat Sunday, especially in our north,
although temps overall return back to normal. Moist profiles, along
with cooler temps, will limit instability. While garden-variety
thunderstorms certainly will be possible, a bit skeptical that much
severe weather will develop despite SPC Day 3 Marginal. The best
thing going for severe risk is probably the shortwave swinging thru,
although its timing is such that effective shear appears best Sunday
night after some stabilization has occurred. As cloud cover and
precip chances increase by Monday, still cooler temps are expected,
maxes being at least a category below normal in the south, and
two-three categories below in the north.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 200 PM Fri: A second deeper shortwave still is expected to
swing across the Great Lakes Tuesday and Tuesday night, and this will
drive a stronger cold front thru the Ohio Valley, which should
eventually induce fairly substantial airmass change for the inland
Southeast. The ECMWF has been consistent in depicting this occurring
in time for Wednesday to be a drier and more settled day. The
Canadian GDPS and GEPS members have generally remained near the EC
solution. The real uncertainty comes as a result of the trend toward
a "more stubborn" front lingering over the area until the cold front
can sweep through, but especially as the subtle delay in the trough`s
arrival creates more of a window for a developing Gulf tropical
system to make northward progress toward our CWA. The poster child
for this possibility is the 12z operational GFS tracking the storm
north to the SW tip of NC. The EC remains on a coastal track, but
several more of the EC ensemble members now show a more inland track
than showed it two days ago. The Canadian GDPS is now in the middle
of the track envelope, so to speak, with the actual circulation
tracking southeast of the CWA but close enough that a part of our
area would likely see heavy rain and minor wind impacts. That said,
its solution hints at a Predecessor Rainfall Event (PRE) as the
tropical moisture flows in ahead of the stronger cold front.
Will maintain likely to categorical PoPs Tuesday given expected
frontal position, but given that many ensemble members still depict
drying setting in behind the cold fropa Wednesday, and the low
confidence in the track of a TC, will advertise no better than chance
PoPs Wed, in our southeast. Below-normal max temps will continue thru
the period.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: An MCS is currently tracking south and east
across eastern TN as of 240Z. This system will continue to push east
towards western NC the next 30 minutes or so while gradually
weakening. The only terminal that has a chance to see brief
SHRA/TSRA in the vicinity is KAVL. Confidence is very low on whether
the MCS will be able to hold together enough to reach KAVL, so
maintained a dry forecast through daybreak. Better TSRA chances
return late Saturday afternoon and early evening as a cold front
approaches out of the N/NW, so have PROB30s at all terminals.
However, 00Z CAMs are not in agreement regarding the overall
coverage of activity for Saturday afternoon. Thus, confidence on the
PROB30s towards the end of the TAF period remains low. Winds remain
NW at KAVL through the period, with some low-end gusts possible
Saturday afternoon. Winds at KCLT should be mostly light and S/SW
tonight. Winds at KHKY, KGSP, KGMU, and KAND will be mainly WNW/W
through tonight. Winds east of the mountains should be mainly N/NNW
on Saturday. VFR will prevail through the majority of the TAF period
outside of the formation of any mountain valley fog and outside of
the TSRA potential Saturday afternoon and early evening.
Outlook: Shower and thunderstorm chances continue Sunday into early
next week as the cold front remains stalled south and east of the
forecast area. Mountain valley fog and low stratus development will
remain possible each morning around daybreak.
&&
.CLIMATE...
RECORDS FOR 08-25
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 92 1998 65 1908 69 2020 50 1952
1936 1930
1925
KCLT 98 1943 71 1927 75 1903 56 1952
1908 1880
KGSP 98 1943 72 1929 73 2000 51 1888
1968
RECORDS FOR 08-26
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 93 1943 64 1879 69 1995 49 1952
1917
KCLT 100 1954 65 1908 76 1903 55 1942
KGSP 100 1943 70 1902 75 1943 55 1917
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from noon to 8 PM EDT Saturday for GAZ018-026-
028-029.
NC...None.
SC...Heat Advisory from noon to 8 PM EDT Saturday for SCZ010-011-
019-104-105.
&&
$$
SYNOPSIS...Wimberley
NEAR TERM...AR/CP
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...AR
CLIMATE...GSP
Area Forecast Discussion
National Weather Service Gray ME
1037 PM EDT Fri Aug 25 2023
.SYNOPSIS...
Showers remain likely into this evening while chances for fog
and drizzle remain through tonight. Scattered showers and
isolated storms continue to be possible Saturday with lower
coverage going into Sunday. High pressure will then return
Sunday night and Monday with fair weather before more rain comes
into play by late Tuesday or Wednesday of next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1035 PM Update...
Showers and patchy drizzle continues to reform over the area
under our very moist and unstable environment. Made minor
adjustments to pops and temperatures with this updated. Patchy
fog will continue across the region overnight.
Update...
Made minor adjustments to pops, dew points and temperatures for
the evening portion of the forecast. Latest radar imagery
continues to shower showers across the region especially over
northern and eastern areas. The latest HRRR shows more
precipitation overnight, mainly relatively light.
After today`s rain, we are now the 8th wettest summer in
Portland`s modern history (records go back to 1868). As of 5 pm,
the precipitation was 16.22 inches of rain since June 1st.
Exactly one more inch of rain prior to September 1st would place
the Forest City in the number seven spot.
Prev Disc...
Weak sfc low is beginning to develop near NYC this after while
low associated with 500 MB trough in well N of the CWA in
Quebec. Forcing has weakened with the system for now as best WAA
has shifted N and E and mid level jet is shifting E as 850 and
700 MB closed lows pass to our N. At this point, think the bulk
of the heavier rain has fallen. Still, once the cluster of
showers current in the mountains and foothills moves out late
this afternoon, should see mainly patch DZ with the chance of a
few SHRA developing almost anywhere, although nothing
significant. Patchy FG/DZ continue overnight as well, and temps
will actually begin to rise a bit this evening, as we lose the
stronger onshore flow and it becomes more S-SW. Expect temps to
to run mostly in the low to mid 60s overnight, but could reach
into the upper 60s across srn NH.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Saturday morning will start with lot of clouds, and maybe some
DZ, but as this low clouds break up in NW flow will see some
breaks of sun later in the morning and through midday outside
the mtns. As the upper level trough passes in the afternoon
expect scattered SHRA/TSRA to develop, at first in the mtns, and
then moving toward the coast in the latter part of the
afternoon. They should diminish around sunset or just
thereafter, So, it doesn’t look like a wash out, but more a
watch the skies and radar kind of day. It will warm up nicely
with highs low 70s in the mtns to the mid 70s to low 80s in the
S. It will also feel humid with Tds in the mid to upper 60s.
Weak N flow Sat night will bring some cooler air in, but It’s
not strong enough to fully mix the drier air down, so lows will
be in the mid 50s to low 60s, with patch fog.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Another wave in the flow aloft will help generate isolated showers
Sunday afternoon, mainly inland. The airmass will be drier
than that of Saturday, which is expected to keep convective coverage
lower. High temps will be generally in the lower 70s.
Once the upper trough pushes east of New England later in the day,
high pressure will build in for Sunday night and into early Monday.
With the high overhead good radiational cooling is expected and have
leaned closer to MOS rather than the NBM for Sunday night`s lows.
This puts forecast lows across northern areas and normally cooler
spots in the 40s while the rest of the area stays in the 50s.
The high will start to shift east on Monday with southerly flow
returning ahead of another trough of low pressure that will approach
Tuesday into Wednesday. A few showers may develop Monday afternoon
in the WAA, but I think these will be pretty sparse in nature given
quite a bit of dry air aloft depicted in forecast soundings. High
temperatures are expected to be in the 70s.
As alluded to previously, models are in pretty good agreement this
far out depicting the next upper trough crossing the Great Lakes
Tuesday and approaching New England as we get closer to Wednesday.
This trough and associated frontal boundary are expected to turn
Tropical Cyclone Franklin farther out to sea in the Northern
Atlantic, well away from New England. However, the trough will bring
us increasing chances for showers and storms generally in the late
Tuesday into Wednesday time frame. Still uncertainty if higher
moisture well on the outer periphery of Franklin can work into the
area, and if it ultimately can, there exists some potential for
locally heavy rainfall. Once the low and front pass, high pressure
looks to bring drier air for Thursday into Friday of next week.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Any improvement this afternoon will likely return
to IFR-LIFR or lower at all terminals tonight in fog and low
cigs. Should see improvement to at MVFR at all terminal late
morning to midday, with VFR into Sat night. Sct SHRA/TSRA could
produce temp restrictions Sat afternoon.
Long Term...Mainly VFR Sunday and Monday, other than valley fog
may occur at HIE and LEB Sunday night. A few showers could
bring brief restrictions during the daytime hours should any
pass over a terminal, mainly on Sunday. Another low pressure
will bring increasing potential for flight restrictions Tuesday
into Wednesday of next week. IFR restrictions look possible due
to low ceilings and visibility reductions within fog and/or
precipitation.
&&
.MARINE...
Short Term...SCA remains in effect through Sat morning fro winds
into this evening, and seas lingering into Sat morning. Given
the swell, it could linger a linger into the afternoon, but
should see sub-SCA conditions by Sat evening.
Long Term...Northerly winds diminish on Sunday as high pressure
builds in later in the day into Monday with conditions remaining
below SCA levels. High pressure shifts east on Monday and Tuesday
with the approach of another low pressure and frontal boundary that
look to cross around Wednesday. SCA conditions are not expected
Monday-Tuesday, but swells from distant Tropical Cyclone Franklin
looks to arrive over the waters Wednesday, potentially
bringing seas back to SCA levels through Thursday. In addition to
this, winds may gust in excess of 25 kt behind the front Wednesday
night and/or Thursday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 11 AM EDT Saturday for ANZ150>154.
&&
$$
NEAR/SHORT TERM...Cannon
LONG TERM...Combs
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
901 PM CDT Fri Aug 25 2023
.SYNOPSIS...
Issued at 838 PM CDT Fri Aug 25 2023
A cold front dropping southward through the region will trigger
scattered thunderstorms tonight into Saturday morning. Once the
front passes, much cooler and less humid conditions will be
observed through next week.
&&
.UPDATE...
Issued at 855 PM CDT Fri Aug 25 2023
Severe thunderstorm watch from Sangamon, Logan, DeWitt and Piatt
counties se until midnight (excluding Champaign, Vermilion, Clay
and Richland counties).
A small MCS recently developed over west central IL early this
evening and has tracked east at 25-30 mph into central IL by mid
morning. A cluster of strong to locally severe storms was
approaching highway 51 between Bloomington and Decatur and was
just east of Lincoln. These storms had a history of producing wind
gusts to around 60 mph with some tree damage near Havana,
Lewistown and Delavan along with frequent lightning and heavy
rains. MCS is fueled by a very unstable air mass with SB CAPES
peaking at 4-6k j/kg over central CWA and unstable air mass with
SB CAPES of 3-4k j/kg extends into southeast IL. The 0-6 km bulk
shear values of 25-30 kts were ne of Springfield and Shelbyville.
Tropical Precipitable Water (PW) values at or just above 2 inches
over heart of central IL aiding in heavy rainfall production.
Luckily the storms are not training so far and lasting around 1
hour or less on eastward journey. We have issued a few Severe
thunderstorm warnings since 630 pm and also mentioned possible
large hail up to 1 inch diameter with the 60 mph wind gust
potential.
A frontal boundary extending from near Quincy to Taylorville to
just south of Mattoon and Terre Haute airports is forecast by
latest CAMs to push south of highway 50 by 09Z/4 am overnight.
After this MCS moves through east central IL through midnight,
feel better chance of additional convection to be tied to this
front in southeast IL overnight into Saturday morning. Lows
overnight in the lower 70s, with some upper 60s north of I-74 and
near 75F at Lawrenceville.
07
&&
.SHORT TERM... (Tonight and Saturday)
Issued at 307 PM CDT Fri Aug 25 2023
19z/2pm analysis shows a band of enhanced Cu developing along a
wind-shift line extending from south of Taylorville to near Robinson.
Will continue to monitor this area for isolated convection over
the next few hours: however, strong mid-level capping will likely
inhibit both the areal coverage and severity of any activity.
Further W/NW, will be watching for additional scattered development
along an old outflow boundary draped across the NW KILX CWA.
Despite mixed layer CAPE in excess of 4000J/kg and a slight uptick
in deep-layer shear due to a short-wave trough digging into the
Great Lakes, very warm temps aloft will continue to prevent
widespread thunderstorm development. CAMs have generally been
delaying convective initiation...with the HRRR now suggesting
around 00z/7pm. With 700mb temps only dropping very slowly from
the 12C reading noted on the 12z KILX/KDVN upper air soundings,
think the cap will hold firm into the evening. A few of the more
vigorous updrafts that develop along the outflow boundary will
eventually be able to break the cap...resulting in widely
scattered thunderstorms from mid-evening through the overnight
hours. A few of the cells will be capable of damaging wind gusts
and large hail, although this does not appear to be a widespread
severe weather event.
A few thunderstorms will linger into Saturday morning along/south
of a Rushville...to Decatur...to Paris line before gradually
shifting further south as the day goes on. By late afternoon, the
effective boundary will slip south of the CWA and a cooler/less
humid airmass will trickle into the region. Lows tonight will
range from the upper 60s far north around Galesburg and Lacon to
the middle 70s south of I-70. Highs on Saturday will be
considerable cooler than today...ranging from the lower 80s north
of I-72 to the upper 80s far south around Flora and Lawrenceville.
Barnes
.LONG TERM... (Sunday through Next Friday)
Issued at 307 PM CDT Fri Aug 25 2023
After that, a prolonged period of cool/dry weather is anticipated
through the extended as a series of short-wave troughs dig a
significant upper trough across the eastern CONUS and the strong
upper high retrogrades to the Desert Southwest. High temperatures
will drop into the 70s and lower 80s while overnight lows dip into
the 50s from Sunday through Friday. Rain chances will be virtually
nil, although will need to keep an eye on Tuesday as models show a
vigorous wave dropping into northern Indiana that could potentially
trigger a few showers.
Barnes
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 606 PM CDT Fri Aug 25 2023
A poorly defined frontal boundary is draped west to east across
central IL, resulting in light/variable wind. We have a large
spread in convective allowing guidance this evening, which leads
to a low confidence forecast for thunderstorm timing and
coverage. Adjusted previous forecast to speed up timing of
potential storms by a few hours this evening, though with low
coverage kept mention to VCTS. If a storm does impact a terminal,
brief reductions to IFR possible. MVFR fog is likely again later
tonight through sunrise, which by briefly drop to IFR in spots.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 10 PM CDT this evening for ILZ027-
029-031-036>038-040>057-061>063-066>068-071>073.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
922 PM CDT Fri Aug 25 2023
...Forecast Update...
.SYNOPSIS...
Issued at 247 PM CDT Fri Aug 25 2023
Key messages...
* Cooler temperatures and rain/thunderstorm chances continue into
the weekend, although, the severe risk is low at this time.
* Drier conditions and a return to warmer temperatures are
anticipated for next week with highs returning into the 90s by the
end of next week.
&&
.UPDATE...
Issued at 919 PM CDT Fri Aug 25 2023
Satellite suggests the best forcing for rain has shifted south and
east of wrn and ncntl Nebraska. A forecast update is in place
using the short term model blend, the HRRR and RAP models. Rain
chances are 30 percent or less the rest of tonight.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 247 PM CDT Fri Aug 25 2023
Cool and wet weather will be the main story through the weekend. The
remnants of Hilary will push significant moisture into the central
Plains tonight and into Saturday. While severe thunderstorms are not
expected, some embedded thunderstorms may be possible with the main
hazard being heavy rainfall. Latest guidance shows a gradual shift
to the south of the heaviest rainfall. At this time, the majority of
the precipitation will fall just south of the Nebraska/Kansas
border. Still, rainfall totals across Chase, Hayes, and Frontier
counties could see up to a quarter inch with locally higher amounts
in any thunderstorms. At this time widespread flooding concerns are
not expected, but some some localized flash flooding concerns,
mainly in low-lying areas and small streams, may be possible.
Rain showers gradually shift southward through Saturday morning,
pushing out of our area completely by the afternoon lasting through
Saturday night. Recent rainfall and cloudy skies will keep
temperatures on the cooler side of guidance. Highs only rise into
the 70s (nearly 10 degrees below normal) with lows Saturday night
dropping into the low to mid 50s.
.LONG TERM...(Sunday through Friday)
Issued at 247 PM CDT Fri Aug 25 2023
For Sunday, a dry forecast is expected through mid-afternoon with
late afternoon showers and isolated thunderstorms possible. At this
time, instability remains limited and any storms that can develop
across the western Panhandle will struggle as they move eastward
into more stable air. Otherwise, temperatures remain near normal in
the mid 80s for Sunday as scattering of clouds will allow for ample
warming of boundary layer temperatures.
A return to drier conditions and gradual warming will continue
through next week. Upper level ridging returns with surface high
pressure building south out of Canada into the Plains. This will
allow for dry weather through the end of the week. Mild warm air
advection will also allow 850 mb temperatures in the 26 to 30 C
range to push into the region. This will result in surface high
temperatures to rise back into the 90s for most locations by next
Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 615 PM CDT Fri Aug 25 2023
VFR conditions are expected to prevail outside of thunderstorms
through tomorrow evening across western and north central
Nebraska. Ongoing showers and thunderstorms will persist into the
early overnight hours before exiting the area to the south prior
to sunrise tomorrow. Brief MVFR will remain possible within
storms. Winds remain gusty for a few more hours this evening
before weakening overnight and shifting easterly, at around 5 to
10kts.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...Kulik
SHORT TERM...Kulik
LONG TERM...Kulik
AVIATION...Brown
Area Forecast Discussion
National Weather Service New York NY
1034 PM EDT Fri Aug 25 2023
.SYNOPSIS...
A slow moving cold front tracks east across the area late
tonight into Saturday morning, with secondary cold front moving
through Saturday evening. High pressure builds in from the
northwest on Sunday and then passes to the north early next
week. An offshore frontal boundary northwest of Tropical Cyclone
Franklin will then briefly backup toward the east coast Monday
and into Tuesday. At the same time, a cold front approaches from
the northwest, passing across the area Wednesday morning. High
pressure builds in for the end of the week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Updated pops based on latest radar imagery and the HRRR which is
still developing scattered showers ahead of a cold front
Latest CAMs still trying to increase shower activity across
eastern LI and SE CT, but based on radar imagery and LLJ slowly
translating east, this is seeming less likely. Still though,
will start off with likely PoPs across this area.
Shortwave trough slides east into tonight. The region will be
in the warm sector ahead of a broad, weak surface low and
attendant cold front. This front should make its way through
overnight into early Saturday morning.
Cold frontal passage late tonight into the morning hours may
trip off additional showers, possibly an isolated thunderstorm.
Best chance will remain across SE LI and CT. No severe or flood
threat with this activity.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
The surface wave pushes offshore Saturday, with the trailing cold
front moving through early in the morning. Absent a few spotty
showers, especially east, drying conditions can be expected in the
wake of this front Sat AM.
Cyclonic flow and lingering weak surface troughing should result in
sct to bkn cu development by the afternoon. Temps run near
seasonable upper 70s to low to mid 80s with offshore flow. A
secondary Canadian cold front approaches late in the day,
sweeping through in the evening hours. An isolated shower or
thunderstorm with the fropa, but a pronounced 750 to 850mb cap
should limit any strong or severe threat from this activity,
with any showers or thunderstorms brief and limited in coverage.
Most remain dry as drier air moves in behind the front as flow
turns NNW into Sunday AM. Followed the superblend of guidance
for this update, with subtle adjustments.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
The mean upper trough will remain where it has most of the
summer across eastern Canada and into the NE quarter of the
CONUS. Periodic shortwave energy traversing the trough will send
another frontal system through the area by midweek. Before then
though, high pressure builds in from the northwest on Sunday
and then to the north across New England on Monday. There could
be an isolated shower across the interior Sunday afternoon with
the departing shortwave trough, along with a reinforcing shot of
cool, dry air into the region.
An offshore frontal boundary stalls on Monday and then even
backups well north and west of tropical cyclone Franklin, which
is forecast to be a hurricane by this time. The system is
progged to stay well offshore with no direct impacts. However,
some indirect impacts will be dangerous rip currents due to an
increasing swell and high surf. As another piece of jet energy
dives southward out of eastern Canada, it will amplify the upper
trough dropping southeast Great Lakes. The latter of which will
send a cold front toward the region. The backing upper flow may
allow for some overrunning showers to work in from the Atlantic
late Monday into Tuesday. Showers/isolated thunderstorms
associated with the cold front will then follow Tuesday night
into Wednesday. An easterly flow preceding the front should not
allow for too much destabilization of the airmass, with perhaps
the exception of areas well north and west of NYC.
Behind the frontal boundary look for a continental polar air
mass with cooler temperatures and comfortable conditions into
the later portion of next week by Thursday. Temperatures overall
through the period will average approximately 5 degrees below
average, with noticeably lower humidity Wed night into Thursday.
Monitor https:/www.weather.gov/okx/tropical for the latest NHC
forecasts on this tropical system and others.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
A warm front remains across eastern Connecticut with a cold
front approaching from the northwest. The cold front passes
through late tonight into Saturday morning. High pressure then
builds to the northwest through Saturday.
Generally VFR, with areas of MVFR ceilings. Expect MVFR ceilings
to become widespread with the approach of a cold front late
tonight. Scattered showers will be possible, and there is a low
chance of an isolated thunderstorm. Low confidence on the timing
of MVFR, and of IFR conditions. If IFR develops expected to be
a few hours with the cold front. Conditions then improve to VFR
behind the cold front.
Winds will be southerly, generally under 10kt inland and 10-15kt at
the coastal terminals, becoming SW late evening and tonight,
then NW towards 12z Saturday.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Mainly MVFR conditions through the overnight, with a low chance
of IFR ceilings, however, not confident to put into the TAFs.
OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
Saturday night-Sunday: VFR.
Monday: VFR, with MVFR/IFR and shra possible late at night.
Tuesday: MVFR or lower in SHRA/TSRA especially in the afternoon and
evening.
Wednesday: MVFR or lower with shra possible.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
SCA remains up only for the ocean waters overnight into
Saturday morning, mainly for seas. A few SW gusts up to 25 kt
early, especially east of Moriches Inlet.
Elevated seas on the ocean may linger near 5 ft into early
Saturday afternoon, though it`s possible they could come down
earlier in the morning.
Sub SCA conditions continue to be favored for Sun into Mon on all
waters (although ocean seas may run 3-4 ft in mixed E and SE swell),
with high pressure building in.
By Monday night into Tuesday look for SE swells to become more
energetic with swells likely building further as tropical cyclone
Franklin lifts north in the Western Atlantic late Monday into
Tuesday. Small craft conditions develop by Tuesday with ocean seas
expected to climb to 5 to 8 ft, highest east of Fire Island Inlet
Tuesday afternoon and Tuesday night. Seas will then begin to subside
Wed into Thu as the Franklin heads up into the North Atlantic.
&&
.HYDROLOGY...
No hydrological concerns at this time through next Friday.
&&
.TIDES/COASTAL FLOODING...
There is a high risk for rip current development for all but the
NYC beaches (moderate) through Saturday due to 3 to 5 ft
southerly wind waves. A gradually building ESE swell on Sunday
will likely produce moderate risk for the LI beaches.
Swells from tropical cyclone Franklin will likely build late Monday
into Tuesday, continuing into midweek, increasing likelihood for
high surf and dangerous rip currents. In addition, a full moon on
Wed Night will have astro tides increasing through the mid to late
week period. Combined with the high surf, the potential for areas of
ocean beach erosion/flooding and scattered areas of dune erosion
increases during the times of high tide Tue/Wed.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through Saturday evening for NYZ080-081-
179.
NJ...None.
MARINE...Small Craft Advisory until 2 PM EDT Saturday for ANZ350-353-
355.
&&
$$
Area Forecast Discussion
National Weather Service Pendleton OR
741 PM PDT Fri Aug 25 2023
.UPDATE...A couple of showers and weak thunderstorms developed
over the Washington Cascade crest region late this afternoon and
the last of them are dissipating at this time. The HRRR has the
activity completely gone in the next hour and the remainder of the
night looks dry areawide. Saturday looks a bit interesting with a
shortwave embedded in the sswly flow aloft forecast to move
across the region. This will help initiate scattered thunderstorms
mainly across central Oregon during the afternoon/evening. The
majority of the activity will occur in areas that have seen
significant rain recently and where fuels are not that receptive.
However some of the activity may bleed into areas that have not
seen much rainfall. Precipitable water is forecast to exceed 1
inch and storm motion will be slow so the storms will likely drop
heavy rain. Therefore will not issue any fire weather highlights
at this time. There is just enough shear and instability forecast
that a couple of the storms could become strong and produce gusty
winds and hail through the early evening hours. 78
&&
.PREV DISCUSSION... /issued 500 PM PDT Fri Aug 25 2023/
SHORT TERM...Tonight through Monday...The deep closed upper level
low will remain fairly stationary off the Pacific Northwest coast
through Sunday. This will allow the western USA upper level ridge to
build into the interior Pacific Northwest over the weekend boosting
temperatures back above normal by around 10 degrees. Temperatures in
the Lower Columbia Basin will be approaching 100 degrees by Sunday
and continue on Monday.
The position of the closed low off the coast and the inland ridge
will place the forecast area under a southerly flow. There will be
enough moisture and weak instability in this pattern to justify a
slight chance (10-15%) of thunderstorms during the late day through
evening period on Saturday and Sunday mainly across central and NE
Oregon. The threat continues Monday but increases (15-25%) as the
closed low off the coast begins to move towards the coast thus more
of the forecast area will become at risk of thunderstorms and
showers.
The light N-NE wind pattern will continue through early Monday but
begins to shift back to westerly late Monday. This will bring the
return of some locally breezy conditions along the east slopes of
the Cascades Monday afternoon and evening.
LONG TERM...Monday night through Friday...The long term will be
characterized by an upper level low bringing southwest flow aloft
and chances of precipitation. As this upper level low moves across,
SW flow aloft will turn to a more zonal direction which will allow
for eastern central Oregon to receive some precipitation along with
some scattered thunderstorms. Finally, another low will build over
the region.
Models are in firm agreement with the initial upper level pattern.
The upper level low that is sitting off the coast will remain
offshore bringing with it southwest flow aloft. There is a slight
variance in the models when it comes to the chances of thunderstorms
Monday night, but the majority of the ensembles and the NBM show
there to be at least a 15% chance of thunderstorms along the Oregon
Cascades and the eastern mountains. However, the models and
ensembles are showing higher chances of precipitation over the Wa
Cascades (60-80%) with decreasing in chances as you move to the
east. However, overnight the models show the upper level low to
finally push onshore. This will increase the chances of rain across
the entire forecast area (60-80%) with the exception of Central
Oregon (>20%). As the system continues to push onshore, models begin
to show increasing CAPE values across east central Oregon and
through the eastern mountains with values of CAPE between 350-650
J/kg. Bulk shear for the same time frame shows speeds up to 40kts
and steep lapse rate of 7.9 C/km. With all this, chances of
thunderstorms along the aforementioned regions is elevated (30-40% )
with <60% chances of rain. NBM is showing the WA Cascades could see
up to 0.5 inches of rain, Northern Blues 0.3 inches and up to 0.1
inches through the Basin and the foothills with some higher amounts
along peaks. Due to the cross Cascades pressure gradient tightening
as the upper level low begins to move onshore, winds through the
Cascades Gaps will increase to between 15-20 mph. Even with the
increase in the winds, RH values are elevated and there are no fire
weather concerns at this time. This pattern will remain in place
through at least Wednesday with continued chances of rain across the
northern portion of the region (30-40%) before drying out Wednesday
afternoon. Models then suggest another low to make its way south
from Alaska by the end of the week, again increasing chances of
cooler and wetter weather.
Temperatures through the period will start off warm before
decreasing steadily each day as the upper level low ushers in cooler
air. Monday will see highs in the 90s and temperatures will decrease
into the 70s and 80s through the remainder of the week. EFI shows
that these temperatures are near above normal Monday, near normal
Tuesday and dropping to below norm on Wednesday and through the
weekend.Bennese/90
AVIATION...00Z TAFs...VFR conditions will prevail through the
period with just some scattered mid clouds. After a little gustiness
in the winds early this evening winds will be mostly 10 kt or less
tonight and Saturday. Thunderstorms are expected to develop in
central Oregon Saturday afternoon but they are not forecast to
impact the TAF sites through 00Z Sunday. 78
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 59 90 62 94 / 0 10 10 0
ALW 61 95 65 97 / 10 0 10 0
PSC 62 96 67 98 / 0 0 0 0
YKM 60 91 64 98 / 0 0 10 0
HRI 61 95 66 98 / 0 0 10 0
ELN 58 91 62 98 / 0 0 0 0
RDM 54 89 58 92 / 0 20 20 10
LGD 58 90 60 93 / 10 10 20 0
GCD 59 91 59 93 / 10 20 30 10
DLS 64 96 66 100 / 0 10 10 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
SHORT TERM...78
LONG TERM....90
AVIATION...78
Area Forecast Discussion
National Weather Service San Angelo TX
652 PM CDT Fri Aug 25 2023
...New AVIATION...
.SHORT TERM...
(This evening through Saturday)
Issued at 207 PM CDT Fri Aug 25 2023
The center of the upper level high will continue to weaken as it
shifts west towards New Mexico. We`re seeing some cumulus
development across the area, indicating we could start seeing
isolated thunderstorms soon. Some of the High res models are a bit
more enthusiastic with the coverage this afternoon and evening than
others. But they generally agree that most of the activity should be
in the southeastern half of our area and that storms should develop
in the afternoon and dissipate after the sun sets.
A boundary is expected to move through our area on Saturday,
approaching our northern counties in the morning and progressing to
I-10 around noon. Winds will shift to the north behind it, but it
will have little impact on temperatures, other than providing some
cloud cover in the afternoon and limiting temperatures slightly that
way. Another Heat Advisory is out for tomorrow. A few of our eastern
and northern counties are borderline Excessive Heat Warning, so they
may need to be upgraded overnight if temperatures are still looking
to exceed criteria. Lifting along and behind the boundary could be
enough to generate scattered showers and thunderstorms. Similar to
today, the HRRR is going much more widespread with the coverage,
putting scattered showers across our whole forecast area. Whereas
the NAMNEST keeps most of the activity in our southern counties,
with a few isolated storms elsewhere. Winds will remain generally
weak in the cloud layer, with wind speeds of 10 to 15 kts. This
along with sufficient moisture in the profile, could allow for
localized areas under storms to see high rain amounts while areas
near it see nothing. Finally, strong winds could pose a threat with
storms that develop, as inverted V soundings suggest microbursts are
possible.
&&
.LONG TERM...
(Saturday night through next Friday)
Issued at 244 PM CDT Fri Aug 25 2023
On Sunday, the upper level ridge will be situated over the Desert
Southwest. At the surface, a weak cold front will drift farther
south into the Conch Valley and Heartland counties and then push
south of the I-10 corridor Sunday night. Temperatures will be a
little cooler on Sunday, with highs 98-104 degrees, highest south
of the front over the southern counties. Scattered showers and
thunderstorms will be possible Sunday and Sunday night, with a
better chance for showers and thunderstorms Monday and Monday
night. Although rain chances will be rather high during this time
frame, amounts look fairly light, with most area likely only
seeing 1/4 inch or less of precipitation. Rain chances will
linger through Tuesday morning, before ending by Tuesday afternoon
over southern sections. Temperatures will be cooler on Monday,
with highs ranging from the lower 90s across the Big Country, to
the upper 90s to around 100 over far southern counties.
A dry and cooler airmass will reside over the area Tuesday and
Wednesday, with highs in the 90s and overnight lows in the 60s.
Tuesday looks to be the cooler day, with most areas only reaching
the low to mid 90s for highs. Dry weather will persist into the
end of the weak, along with slightly warmer temperatures.
&&
.AVIATION...
(00Z TAFS)
Issued at 652 PM CDT Fri Aug 25 2023
Some scattered showers and thunderstorms should diminish around
sunset this evening. Otherwise, winds will go light and variable
overnight before turning out of the north late tomorrow morning.
Another round of scattered showers and thunderstorms are possible
late tomorrow afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 104 79 104 77 / 10 10 20 20
San Angelo 103 77 103 76 / 20 10 30 30
Junction 102 74 102 74 / 20 20 30 10
Brownwood 104 78 103 77 / 20 10 30 20
Sweetwater 102 79 104 77 / 0 10 20 20
Ozona 98 74 99 74 / 20 10 30 20
Brady 102 77 101 77 / 20 20 30 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for Brown-Callahan-
Coke-Coleman-Concho-Fisher-Haskell-Jones-Kimble-Mason-McCulloch-
Menard-Nolan-Runnels-San Saba-Shackelford-Taylor-Throckmorton-
Tom Green.
Heat Advisory from 1 PM to 9 PM CDT Saturday for Brown-Callahan-
Coke-Coleman-Concho-Fisher-Haskell-Jones-Mason-McCulloch-Nolan-
Runnels-San Saba-Shackelford-Taylor-Throckmorton-Tom Green.
&&
$$
SHORT TERM...AP
LONG TERM....24
AVIATION...SK