Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/02/23
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
435 PM AKDT Sat Jul 1 2023
.ANALYSIS AND UPPER LEVELS...
A large upper level low continues to churn nearly in place as it
pivots around the central Aleutian islands. This is generating
widespread clouds and periods of rain showers over the NPac into
the western Gulf. The ridge of high pressure stretching from the
Bering Strait to the western Aleutians has trapped a layer of
stratus over that area.
Meanwhile, clouds have also spread in over the Alaska-Yukon border
from east to west over the Copper River Basin. A weak upper level
shortwave has generated a few showers over Prince William Sound.
This leaves partly to mostly sunny conditions over much of
Southwest into South Central Alaska. There may be enough
instability in these regions when combined with the affects
of terrain for a passing light rain shower.
&&
.MODEL DISCUSSION...
Overall, model solutions continue in good agreement with the
synoptic features. They seem to have aligned on timing of the
arrival of the front over Kodiak Island and the southern Bering,
however the extent of the Gale Force winds is more in question,
with the ECMWF, Canadian-Reg, and HRRR showing a less extensive
area. The GFS and NAM are a little more bullish on wind speeds.
NAM/GFS show the highest precip chances and highest wind speeds
moving across Kodiak Island and the eastern Aleutians later today
and tonight.
Otherwise, with a large upper level low generally south and west
of the mainland, expect overall weather conditions to remain
generally unsettled with widespread cloud cover and precipitation.
&&
.AVIATION...
PANC...VFR conditions will persist. A slowly strengthening surface
ridge along the north Gulf coast will lead to development of a
Turnagain jet this evening. Confidence is high that gusty
southeasterly winds will bend into the terminal no later than 06Z,
but possibly an hour or two earlier than that. Winds will bend
down Inlet and out of the airport early Sunday as a front lifts
northward across the Gulf. However, they will move back Sunday
afternoon, albeit weaker, with the strongest winds remaining over
the northern Inlet. Ceilings will gradually lower through the day
Sunday as light rain makes its way up Cook Inlet, though the
southeast flow will ensure VFR conditions.
&&
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: This
afternoon through Tuesday afternoon)...
High pressure briefly bestowed itself upon Southcentral Alaska
with its mostly clear skies and sunshine today. Not every
location saw sunshine though. A shortwave moved over the eastern
Copper River Basin near the Wrangells today where the area dealt
with rain and clouds this morning. This has produced cooler
temperatures than what was forecast. The second area not to
experience sunny skies is Kodiak Island, where the marine layer
has been intermittent over the island in addition to high clouds
ahead of a front expected to reach the southern tip of the island
by the late afternoon into the evening. The one day of summer then
comes to a close as the fall pattern gets back underway.
Starting late this evening, the aforementioned front will begin
to impact the weather across much of Southcentral. Wind will be
the first feature of note as mass convergence generates a coastal
ridge ahead of the main front. This will induce a pressure
gradient and subsequent response in the wind field to produce gap
winds through the Turnagain Arm, Knik Arm, and the Copper River
Valley. The response in the wind field will start overnight
tonight and increase in intensity through Sunday afternoon before
slowly weakening in the evening and overnight.
Rain associated with the front will reach the southern Kenai
Peninsula Sunday morning, pushing north into the Anchorage area
and Mat-Su Sunday evening. Downsloping looks to be confined only
to close proximity to the mountains, so intermittent to steady
light rain is looking likely overnight Sunday and into Monday for
most of the Cook Inlet areas. The front is then expected to stall
and weaken in place over Prince William Sound through Monday
morning. There will also be another resurgence of southeasterly
gap winds Monday, especially during the afternoon and early
evening hours as the pressure gradient re-tightens. A chance of an
isolated thunderstorm or two is possible Monday afternoon into
early evening for northeast portions of the Copper River Basin
close to the Alaska Range.
Yet another upper level wave lifts northward over Kodiak Island
and into Southcentral overnight Monday into Tuesday, producing
another period of widespread rain. And as if it wasn`t enough,
another frontal system, in association with an Aleutian low, looks
to lift northeastward again over Kodiak Island Tuesday afternoon
through the evening. The result will be more rain. Stay tuned as
there will be fine-tuning on the northward progress of this front
through the middle of the week.
.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
Southwest Alaska is currently enjoying some clearer conditions
with drier air moving through the region from the Kamishak Gap.
With the incoming winds, drier conditions across Southwest Alaska
this weekend are expected, with clearer skies allowing for much
more surface heating. High temperatures today will be matched by
cooler temperatures overnight tonight, due to the clear skies. The
warmer temperatures this afternoon may induce some convective
showers and some isolated thunderstorms late this afternoon and
evening. Any thunderstorms will likely be contained to the Middle
and Lower Kuskokwim Valley as they host the most favorable
convective ingredients, however dryness will likely still inhibit
deep convective cells from developing. Sunday will not be as
clear as the surface low in the Northern Pacific enters the
Southern Bering, swinging a front of precipitation into Southwest.
By late Sunday morning, winds along the front will amplify the
Easterly winds already pulling through the Kamishak Gap, raising
the likelihood for much gustier winds in the Greater Bristol Bay
area. The core of gusty winds is expected to set-up along the
southern edge of Lake Iliamna, between Igiugig and Kokhanok, with
gusts that may reach up to 50 mph. This core of winds will likely
diminish by Sunday afternoon. Rain associated with the front will
linger however, with widespread light rain to set-up across
Southwest Alaska Sunday morning, persisting yet transitioning to
showers into the early workweek.
.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...
A low pressure system continues to hold steady over the Southern
Bering Sea and Aleutian Chain. This system has brought widespread
clouds and rain to much of the Chain as well as some low clouds in
the Pribilofs. The low pushed a front across the Eastern Aleutians
today, and as we approach this evening, winds and gusts along
the front will diminish sharply by the overnight hours. Winds are
expected to hold their direction through Sunday as the surface low
slowly moves northward across the Aleutian Chain. The low is then
expected to weaken, giving way for weak ridging to build in the
Western/Central Aleutians that will gradually enter the Eastern
portion of the Chain by Sunday evening. Sunday morning however, a
new front will enter the Western Bering bringing a wave of rain to
the Western Aleutians by Sunday morning. This front is expected
to advance steadily eastward, reaching Adak by late Sunday
night/Monday morning.
&&
.LONG TERM FORECAST (Days 4 though 7: Tuesday through Friday)...
The long-term forecast continues to be dominated by the same
weather pattern with low pressure in the Bering and high pressure
extending into portions of eastern Alaska. High-end small craft
winds to gale-force winds are expected to accompany the
aforementioned low as it tracks eastward towards the Southwest
coast. Model spread grows in relation to where the exact track of
the low will be and its strength, therefore, impacting the
precipitation and wind forecast. However, models are giving strong
indications of southerly and southeasterly gap flow winds
persisting. Expect windy and wet conditions along the Alaska
Peninsula and the Great Bristol Bay region for Wednesday morning
and then gradually tracking into Southcentral for Thursday
afternoon through Friday. Forecast confidence overall is
moderately low given the discrepancies on the low placement/track
and its strength.
&&
$$
SYNOPSIS AND MODEL DISCUSSION...NR
SOUTHCENTRAL ALASKA...DN
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CL
LONG TERM...MK
Area Forecast Discussion
National Weather Service La Crosse WI
1027 PM CDT Sat Jul 1 2023
.DISCUSSION...(This evening through Saturday)
Issued at 254 PM CDT Sat Jul 1 2023
Key Messages:
- Scattered showers/storms tonight into Sunday morning, generally
holding across northeast IA/southwest WI
- Shower and storm chances for the holiday week, especially
Tuesday night into Wednesday/Severe weather potential
- Heat Monday and Independence Day - Temperature and Heat Index
Values mid-80s to mid 90s
TONIGHT INTO SUNDAY MORNING - scattered showers, storms...mostly
holding over northeast IA/southwest WI:
Upper level trough located over the central plains early this
afternoon will continue to slowly lift east/northeast tonight into
Sunday. Bits of shortwave energy are preceding the trough, with one
of those evidenced via convection across central/eastern IA.
Further, a frontal boundary continues to hover across
central/northern IA into northern IL/southern WI. The RAP gives this
front a little push into northeast IA/southwest WI this evening as
the upper level trough edges east. Not strongly convergent, but will
provide an additional focus for convection. 300 mb jet max also
wants to lend a hand with some lift provided by the left exit region
this evening.
While the deep pool of moisture/instability should hold southward,
the RAP develops 500-1000 MUCAPE over northeast IA/southwest WI by
00z. Little if any shear to work with. RAP soundings also point to
convective temps being reached later this afternoon. Also signals
point toward continued scattered convection continuing to spark, but
again, mostly holding over parts of northeast IA/southwest WI.
Highest chances likely from late afternoon through the evening.
Spotty, more isolated chances (20%) will linger into Sunday - at
least until the trough passes east by the afternoon.
Sunday night through the Independence Day holiday week:
Sunday night into Monday night, we have upper level ridging with
northwest flow aloft across the forecast area. A weak shortwave may
drop southeast across the forecast area in the flow aloft Sunday
night into Monday. The trough to the east moves into New England
and the closed low over Saskatchewan is heading into Manitoba.
Through much of the work week, we`ll be under the influence of
this next trough with increased rain chances. Although we have
some rain chances with weak waves/pre-frontal trough our better
chances for more widespread rainfall should occur with the cold
front.
A pool of instability increases ahead of a cold front and remains to
the northwest of the forecast area Sunday night, but some weak
instability does shift eastward overnight along with steepening
lapse rates and a pocket of weak 0-6km shear by Monday morning. The
forcing weakens in the morning, however instability does re-build
during the afternoon. Our blend gives us a dry forecast overnight
and Monday morning with a 20-30% chance for storms north of I90
Monday afternoon. Forecast soundings show some MLCIN and weak
instability, but sometimes this can be overcome in northwest flow.
01.12Z HREF has some members (ARW/NSSL/NAMNest) that do have
precipitation making it into our west. We`ll need to continue to
assess/metwatch for any storms that develop across Minnesota to see
if they can hold together as they drop southeast Monday morning when
we get closer to that time period. We currently have highs in the
90s Monday, however if any clouds persist/there is outflow from
storms to the north, this could affect highs.
There remains timing differences as to when the cold front moves
through the forecast area and if the front pushes through Tuesday
night or Wednesday. Part of this is related to a shortwave pushing
the front into the area Tuesday afternoon, but stalling somewhat
until a stronger wave arrives Wednesday. The NAM/GFS are trending
earlier than the EC with the fropa. Ahead of the front, with the
instability axis in place and we remain uncapped, we will be prone
to shower and thunderstorm chances with any ripples that move
through. Thunderstorm chances increase with rain chances becoming
more widespread Tuesday night and Wednesday. Warmer temperatures
aloft try to build in and this may limit the southward extent of
the rain initially, but this will be overcome with the front
moving in. Rain chances linger Wednesday with cooler temperatures.
Drier air moves in for Wednesday. The grand ensemble has a 30 to
70% chance for 0.10" or more of rain before midnight, with higher
chances in the northwest part of the forecast area, thus those
with activities will be watching the forecast closely.
There is the potential for severe storms, however details will
have to be worked out as we get closer to Tuesday/Wednesday.
Temperature and Heat Index Values are forecast to be in the mid-80s
to mid 90s Monday and Tuesday. These highs will be dependent on the
cloudcover/where the precipitation is occurring.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1028 PM CDT Sat Jul 1 2023
There will be scattered to broken high clouds through Sunday
evening. Winds will be northerly at 5-10 knots. Visibilities will
remain VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Rieck/Zapotocny
AVIATION...Boyne
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
939 PM CDT Sat Jul 1 2023
.UPDATE...
Issued at 939 PM CDT Sat Jul 1 2023
Isolated convection continues over northwest to north central North
Dakota this evening. SPC mesoscale analysis depicts 0-6km shear
approaching 30 kts across the northern border, which combined with
MLCAPE of around 3000 J/kg has allowed for a couple severe
thunderstorms to develop. Isolated convective activity with some
very isolated strong to severe thunderstorms may continue overnight
as 850mb warm air advection along the mid-level lapse rate gradient
over central North Dakota should provide a modest initiation zone
for elevated thunderstorms overnight. With this update precipitation
chances were extended utilizing recent HRRR runs to cover central to
eastern North Dakota overnight, into the south central to south east
through Sunday morning.
UPDATE Issued at 603 PM CDT Sat Jul 1 2023
This evening, scattered convection was ongoing over northeast
Montana, in an area of surface pressure falls. Further east, a few
cumulus towers have undergone convective initiation along a
convergence boundary from Burke/Renville counties south into Stark
county. With just weak convergence from this boundary and the
upper level support still off to the west, convection so far has
struggled to maintain growth much beyond initial lightning
strikes. This evening it looks likely that initial convection
along the eastward boundary should remain very isolated, while
convective coverage increases with thunderstorms moving in from
northeast Montana. While very steep low level lapse rates
contributing to 1200-1500 J/kg of DCAPE may allow for a few
isolated stronger wind gusts, the lack of bulk shear will keep
the severe thunderstorm threat low tonight. Lightning as well as
locally heavy rainfall will be the main hazards. Going into Sunday
morning, the longevity of the overnight convection into central
and eastern North Dakota is questionable but we may see some
isolated activity continue past sunrise with modest support from
850mb warm air advection and the embedded impulse aloft. Will let
00Z data come in this evening to see if any morning precipitation
chances need adjusting or increasing.
&&
.SHORT TERM...(Today through tonight)
Issued at 230 PM CDT Sat Jul 1 2023
Forecast highlights in the short term period will be chances for
showers and storms.
Currently, subtle embedded energy continues to move across the
general area, along with decent early July MUCAPE around 3K J/KG.
A few agitated CU fields showing up southwest and southeast where
we`ve had an occasional updraft/shower develop, though lack of any
shear and stronger forcing is keeping a lid on things at the
moment.
Will continue to see spotty chances for convection this
afternoon/evening, though the better activity and best chance for
stronger storms does appear to be this evening across the west
when a more defined mid level impulse advances east over a sfc
trough along the ND/MT border area, along with some increase in
wind shear. Still, will need to monitor storms through peak
heating with the amount of instability present as pulse severe
cannot be ruled out.
.LONG TERM...(Sunday Night through Saturday)
Issued at 230 PM CDT Sat Jul 1 2023
A warm and active pattern will start the week, followed by cooler
and quieter conditions.
Sunday remains the warmest day for the upcoming week, with
boundary layer temperatures near 30C and a decent westerly breeze
which will promote better mixing than we are seeing today. Highs
will range from the mid 80s to mid 90s across the local area,
though heat index values should be slightly less as dry air also
advances into the region west to east. Best instability will thus
remain over eastern ND where boundary layer moisture lingers the
longest, and where SPC has the Marginal risk outlook over the
northern Red River Valley. Result is a low if not zero chance for
thunderstorms during the day Sunday.
Sunday evening through early Monday a cold front begins to push
across the state, and will be the focus for showers and
thunderstorms. An isolated strong to severe storm is possible
mainly across the far south near a lingering boundary, and this
area is indicated in SPC`s Day 3 Marginal Risk. There is a lot of
shear to work with along this front, however, the instability is
lacking this time. A few storms could still produce some large
hail and gusty winds. The aforementioned front stalls across the
south Monday, and better instability looks to return along with
modest shear. Thus thinking is we could see strong to severe
storms not only Sunday night, but another round as well during the
day Monday, again across the south. Will continue to monitor.
Independence Day will be a post frontal day, with temperatures on
the cool side, generally in the 60s and 70s. Breezy northwest
winds will also look to be found across much of the area. Given
the lingering upper trough over the Northern Plains, NBM is still
lingering chances for showers and thunderstorms, especially in
the south. Chances do trend downward throughout the day however.
The rest of the week is then in a cool and mainly dry, though will
see a slight uptick in temperatures as we go through the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 603 PM CDT Sat Jul 1 2023
Chances for isolated to scattered thunderstorms increase this
evening, initially around KXWA-KDIK-KMOT, though coverage around
KDIK should be rather isolated. Gusty erratic winds will be
possible with any thunderstorm tonight along with brief periods of
heavy rain and reduced visibility. Otherwise VFR conditions are
expected outside of this convective activity. Light winds tonight
turn to the west on Sunday, increasing to 15 to 25 kts in the west
and north.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...AE
SHORT TERM...NH
LONG TERM...NH
AVIATION...AE
Area Forecast Discussion
National Weather Service Birmingham AL
1025 PM CDT Sat Jul 1 2023
...New SHORT TERM...
.SHORT TERM...
(Rest of Tonight)
Issued at 1019 PM CDT SAT JUL 1 2023
The radar is now quiet. Any echoes for the next few hours will be
isolated at best. Have adjusted pops downward accordingly. The
excessive heat warning has expired. We continue with a heat
advisory for all of Central Alabama through Sunday evening. May
need to upgrade some of the SRN counties to a warning for Sunday,
but will see what the 00z data looks like to determine for the
morning issuance. Otherwise, the overnight lows are similar with
only a few minor changes after obs/hires data has been added for
tonight.
08
Previous short-term discussion:
(This evening through Sunday)
Issued at 114 PM CDT SAT JUL 1 2023
Elongated ridging extended from over the Western Gulf of Mexico
northeast to over the Southern Appalachians while a longwave
trough was over the Central Plains. Surface high pressure extended
from the Eastern Ohio River Valley south to the Northern Gulf of
Mexico. A stationary front extended from Northwest Missouri
southeast into Northern Alabama.
The wet microburst risk is high today with the best potential
across the north and west. Most storms will produce gusty winds
with some damaging winds possible from the heavier activity.
This afternoon.
Broad mid level ridging will remain in place over the area this
afternoon, though a shortwave analyzed by RAP mesoanalysis
continues to move east over much of Tennessee and Northern
Alabama. This weakness aloft is continuing to support the
development of thunderstorm activity with more organized heavy
activity to the north.
Our northeast counties, generally east of Interstate 65 and north
of Interstate 20 have the greater potential to experience heavy
thunderstorms this afternoon. Outside of more organized activity
north and northeast, isolated showers/thunderstorms will develop
across portions of our central counties due to the high
instability values despite strong subsidence from ridging aloft.
Damaging winds and some hail will be possible from the heavier
activity with best chances across the northeast counties. Heat
index values will continue to exceed 105 degrees across most areas
this afternoon as high temperatures reach the upper 90s with dew
points remaining in the mid to upper 70s. Winds will be from the
west to northwest at 4-8 mph outside of convection.
Tonight.
The flow pattern aloft will gradually become more zonal with time
overnight as the ridging flattens to our east while the longwave
trough moves east, becoming extended from over the Great Lakes
southwest to over the Central Plains. Surface high pressure will
become positioned further to the south and southeast of the area
while a surface front pushes southeast across the Central and
Southern Plains while a surface trough remains positioned across
the northern portion of the area.
Lingering shower and thunderstorm activity will continue through
the evening while gradually decreasing overnight. Balmy conditions
will persist overnight with lows ranging from the low 70s north
to the mid 70s south and central. Winds will be light from the
south at 3-6 mph.
Sunday.
Mid-level ridging will move over the Southeastern Atlantic Coast
while the positive longwave trough will extend from over the
Eastern Great Lakes south to over the Mid-South Region. Surface
high pressure will move further southeast of the area while a
front will continue to advance southeast across the Midwest into
the Southern Plains.
With the ridge flattening aloft along with existing outflow
boundaries from convection today, there will be an overall slight
increase in shower and storm chances across the area on Sunday. A
few of the storms may be strong to severe due to continued high
amounts of low-level instability. Heat index values will continue
to exceed 105 degrees areawide, resulting in continued heat stress
concerns. High temperatures will range from the mid 90s north and
east to the upper 90s south and central. Winds will be from the
southwest from 5-10 mph.
05
&&
.LONG TERM...
(Sunday night through next Friday)
Issued at 322 PM CDT SAT JUL 1 2023
The unsettled weather pattern will continue over the next several
days, with daily chances for showers and thunderstorms through the
forecast period. This forecast update remains largely consistent
with the previous message, with highs in the low to mid 90s and heat
indices in the 100-105F range. PoPs remain high each day in the
extended but were lowered slightly from consensus to account for
uncertainty in spatial and temporal coverage each afternoon. Severe
weather and heat remain the main messaging points for the next few
days, with a current severe risk for Monday and the aforementioned
100+ heat index expected through at least midweek for areas that do
not receive ample rainfall to limit the highest temperatures.
12
Previous long-term discussion:
(Monday through Friday)
Issued at 336 AM CDT SAT JUL 1 2023
The overall synoptic pattern doesn`t change much during the upcoming
week. The now flattened ridge remains to our south as a longwave
trough is stretched through much of the Midwest just to our north.
We`ll have ample moisture advection each day with the southerly flow
and the proximity of the trough to our north will support scattered
to numerous showers and thunderstorms each day, with the greatest
coverage in the afternoons. A few of these storms could be strong to
severe.
Along with the thunderstorms each day, we`re also still looking at
the potential for heat impacts Monday through at least Wednesday.
Temperatures will certainly be lower compared to the past few
days, but humidity remains elevated leading to higher heat
indices. Any convection should limit the extreme heat; however,
in locations that don`t see rainfall, or see rainfall after peak
heating, heat indices could still reach into the 100-105 degree
range. There`s still a good amount of uncertainty for the high
temperatures and heat index for Monday through Wednesday because
of the expected thunderstorm coverage, but given the extended
period of this current heat wave, I`ll continue mentioning heat
impacts in the hazardous weather outlook through at least mid-
week.
25/Owen
&&
.AVIATION...
(00Z TAFS)
Issued at 710 PM CDT SAT JUL 1 2023
Showers and thunderstorms persist but are currently decreasing in
intensity and coverage. Activity may go on for another couple of
hours but the deteriorating trend should continue. Winds should
become more light/variable. During the day Sunday, winds should
pick back up to 6-9kts from the SW-W with mixing. More TSRA is
possible with heating for Sun afternoon.
08
&&
.FIRE WEATHER...
Hot and humid conditions through the weekend and early next week,
with afternoon and evening thunderstorms expected each day. Min RH
values today and tomorrow near 45-50 percent with afternoon heat
indices 105-112F each day. Light westerly 20ft winds this evening
becoming southwesterly at 5-8 mph on Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 71 96 72 93 / 20 40 30 50
Anniston 73 95 73 91 / 20 40 30 50
Birmingham 76 98 74 93 / 20 40 30 50
Tuscaloosa 76 98 74 93 / 20 40 30 50
Calera 74 96 73 91 / 20 40 30 50
Auburn 74 94 73 91 / 20 40 30 50
Montgomery 75 97 74 93 / 20 40 20 50
Troy 75 97 74 95 / 20 40 20 50
&&
.BMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM CDT Sunday for the following counties:
Autauga-Barbour-Bibb-Blount-Bullock-Calhoun-Chambers-Cherokee-
Chilton-Clay-Cleburne-Coosa-Dallas-Elmore-Etowah-Fayette-Greene-
Hale-Jefferson-Lamar-Lee-Lowndes-Macon-Marengo-Marion-Montgomery-
Perry-Pickens-Pike-Randolph-Russell-Shelby-St. Clair-Sumter-
Talladega-Tallapoosa-Tuscaloosa-Walker-Winston.
&&
$$
SHORT TERM...08/05
LONG TERM....12/25/Owen
AVIATION...08
Area Forecast Discussion
National Weather Service Boston/Norton MA
954 PM EDT Sat Jul 1 2023
.SYNOPSIS...
Higher humidity returns Sunday, along with increased rain
chances late in the day. Warm and humid weather Monday and
Independence Day, with the potential for scattered showers and
thunderstorms. The greater risk should be Monday, especially
across interior southern New England, but by no means a washout
with many hours of dry weather. Trending drier for mid to late
next week, but warmer than normal. Heat indices into the lower
to mid 90s are possible across Southern New England most of
this upcoming week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Update: 10 PM - Not much weather this evening across southern
New England, though, northern New England does have some showers
and storms. The latest 00z HRRR does keep those showers well to
our north this evening and much of tonight. That said, some
light rain is possible early morning, likely after 4am, across
western CT & MA. Current forecast does handle this well, with
increasing POPs, to `chance`, across the western CWA before
dawn. All that said, the forecast remains well on track for this
evening. But, the biggest difficulty is with low stratus and
fog offshore which will continue to impact coastal locations
through the night. As of this update, low vsby are over the
Cape and Island, less than a mile.
Previous Discussion...
An elongated longwave trough over the Great Lakes begins to
send impulses of shortwave energy into the region along with
moisture-rich SE flow. The strongest forcing for showers
overnight looks to remain in NY, with some showers moving into
western MA and CT near dawn. As the increased moisture rolls in,
so does low cloud cover. Overnight lows likely remain higher
than last night, only dropping into the mid 60s. Locally dense
fog is possible again overnight, especially for the southern
coasts, along with Cape Cod and the Islands.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
The upper level trough advances slightly to the east, along
with an associated surface low. A warm front out ahead of this
surface low will bring widespread showers, with a few
thunderstorms also possible. The best chance for showers looks
to be across central and western Massachusetts due to the extra
forcing from the upper level trough. Severe weather will likely
not be an issue tomorrow with instability being rather meager,
as the HREF is showing well less then 500 J/kg of MUCAPE. Heavy
rain will be the primary concern with any showers as PWAT values
are between 1.5 - 2.0 inches. Although there will be some off
and on showers, its not looking like an all-day washout. Cloud
cover and rain showers have caused the models to trend highs a
bit lower into the mid to upper 70s. Sunday will also feel very
muggy with dew points rising into the upper 60s to lower 70s.
The upper level trough continues to push NE overnight Sunday,
with continued SW flow and warm air advection. Scattered showers
along with a rumble of thunder will remain through the night.
As with Sunday afternoon, PWATS will still be near 2.0 inches
meaning heavy rain is possible with any shower. A 40-50 knot LLJ
looks to set up across SE Massachusetts, along with Cape Cod
and the Islands. This will allow for greater forcing, leading
to higher shower chances overnight. Thunder chances also appears
higher over SE MA overnight with MUCAPE above 500 J/kg.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Highlights...
* Warm and humid conditions continue on Monday and Independence Day
with scattered showers/thunderstorms and the potential for a few
strong to severe storms.
* Trending drier but warmer with elevated humidities the rest of the
week with the return of highs in the 90s.
* Unsettled weather and cooler temperatures look to return around
next weekend.
Details...
Monday and Monday night...
The core of the low level jet associated with the shortwave trough
to our west shifts offshore Monday morning taking taking the showers
and embedded thunderstorms with it. Meanwhile we remain downstream
of the trough and as such under warm and moist southwest flow
through the day. Guidance is indicating this will result in decent
low cloud cover early on Monday, but eventually seeing a good amount
of clearing as low levels mix out by late morning/early afternoon.
This should allow for temperatures to climb into the 80s with
dewpoints in the low to mid 70s leading to a lot of instability.
Global guidance is indicating up to 2,000 J/kg of MUCAPE. As for
placement, the SREF indicates the location of greatest instability
will be over interior (western/central) MA and CT. BUFKIT depict a
850 mb cap eroding by early afternoon. By then the instability with
some assistance from divergence aloft in the left exit region of an
upper jet will begin to sprout isolated to scattered thunderstorms.
0-6 km bulk shear values are not great for organized severe
convection at 25 to 35 kts, but certainly enough to see a handful of
severe storms, mainly north of the Hartford-Providence-Boston line.
At this point the SPC has most of the region under general thunder
with just a portion of CT in a marginal risk of severe weather but
wouldn`t be surprised to see that expanded a bit if things line up
just right. The main risk would be from gusty winds and localized
urban/poor drainage flooding if a storm goes over the wrong area
given PWATs nearing 2 inches. Storms will weaken at we go into the
evening and instability decreases, but a heavy shower/thunderstorm
or two may impact eastern MA. Lows will we very mild overnight given
the humid airmass, in the upper 60s/low 70s.
Independence Day...
Tuesday the trough axis moves overhead as does its surface
reflection which will bring the risk of scattered showers and
thunderstorms in the afternoon once again. Some of the global
guidance is indicating less instability on Tuesday compared to
Monday while the SREF`s probabilities of MUCAPE>1000 j/kg are around
the same, so there is some uncertainty as we`re on the fringe of the
higher resolution guidance. At this point it is looking like the
best jet dynamics and shear don`t line up with the best instability
so Tuesday would feature a lesser severe threat than Monday. The
SREF does show a lower probability of severe weather on Tuesday.
However, there is enough overlap of instability and shear there that
an isolated strong to severe storm can`t be ruled out. The best
chance looks to be interior NW southern New England at this time,
with a much lesser chance toward the coast.
Wednesday through Saturday...
Wednesday and Thursday mid level ridging builds in at the mid levels
with high pressure at the surface. Subsidence should help keep
things dry with plenty of sun which, with 850 mb temperatures in the
16-18C range should result in high temperatures creeping back into
the low 90s for many of our typically hottest locations (CT Valley
and eastern/northeastern MA/Merrimack Valley). Additionally,
humidity won`t be relenting with dewpoints in the upper 60s/low 70s
so it will feel quite muggy out. Our next chance of rain comes
toward the weekend with an approaching mid level shortwave which
will dig into the mid Atlantic around Saturday bringing unsettled
weather with it.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00Z update...
Tonight...Moderate Confidence.
Low stratus and fog redevelops, with IFR-LIFR conditions likely
for terminals near the south coast, Cape and Islands. Elsewhere,
cigs/vsbys probably not as low as this morning with a light
southerly component to the wind, as opposed to more of a light
easterly flow early this morning. Still expect widespread MVFR
to marginal IFR conditions to develop overnight in low clouds
and patches of fog. Mainly dry, but a few showers possible
toward daybreak across the distant interior.
Sunday...High confidence.
VFR to MVFR conditions, nearing IFR across western MA/CT. Rain
chances increase from west to east during the afternoon and
evening. Winds are south/southeast 5 to 10 kts.
Sunday Night...Moderate confidence.
Mainly IFR, with areas MVFR possible. Breezy. Chance SHRA,
with isolated TSRA. Patchy BR.
BOS Terminal...High Confidence in trends, but lower confidence
in specific timing.
BDL Terminal...High Confidence in trends, but lower confidence
in specific timing.
Outlook /Monday through Thursday/...
Monday: Mainly VFR, with local IFR possible. Breezy. Chance
SHRA, isolated TSRA.
Monday Night: VFR. Chance SHRA, isolated TSRA.
Independence Day: VFR. Slight chance SHRA, isolated TSRA.
Tuesday Night through Thursday: VFR.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
High confidence.
Rather tranquil boating conditions into Sunday night. Increasing
southerly winds late Sunday night, but mostly with gusts less
than 25 kt. Some reduced visibility at times due to a
combination of smoke/haze and fog. Visibility could be less than
1 nm at times overnight into Sunday morning. Increased rainfall
chances Sunday afternoon into Sunday night.
Outlook /Monday through Thursday/...
Monday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain
showers, isolated thunderstorms, patchy fog. Local visibility
1 to 3 nm.
Monday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain showers, isolated thunderstorms.
Independence Day: Winds less than 25 kt. Areas of seas
approaching 5 ft. Slight chance of rain showers, isolated
thunderstorms.
Tuesday Night: Winds less than 25 kt. Seas locally approaching
5 ft.
Wednesday through Thursday: Winds less than 25 kt.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT this evening for CTZ002>004.
MA...Air Quality Alert until midnight EDT tonight for MAZ002>021-
026.
RI...Air Quality Alert until midnight EDT tonight for RIZ001>008.
MARINE...None.
&&
$$
SYNOPSIS...Belk/BW/KP
NEAR TERM...BW/Dooley/KP
SHORT TERM...KP
LONG TERM...Frank
AVIATION...Belk/BW
MARINE...Belk/BW
Area Forecast Discussion
National Weather Service Cleveland OH
1010 PM EDT Sat Jul 1 2023
.SYNOPSIS...
A broad frontal boundary will linger across the southern Great Lakes
through Sunday morning. A weak wave of low pressure will track along
this front overnight into Sunday, eventually pulling a cold front
south across the area on Sunday night. Weak high pressure will
arrive in the region Monday into Tuesday.
&&
.NEAR TERM /THROUGH SUNDAY/...
9:30 PM Update...
The convection has fizzled across the area with just patchy
showers left. Watching the MCS moving into central Indiana. This
is tied to a shortwave that will cross the region overnight.
Cloud tops are warming, so expect the system to be weaker as it
moves across the area overnight with no severe weather expected.
Locally heavy rainfall will be the main concern.
6:30 PM Update...
Increased PoPs from NW Ohio across the lakeshore counties to NW
PA over the next few hours. Continued warm/moist advection and
breaks of sunshine has allowed a band of convection to form
along what appears to be an outflow boundary that is slowly
lifting NE. This could also be on differential heating
boundaries as well. There is very little shear, but mean cloud
layer winds are just strong enough (25 knots) to keep the
convection moving, although we will need to watch for any
training since PWATS are nearing 2 inches (90th percentile) with
warm cloud layer depths and skinny CAPE, so efficient rainfall
will continue with any cells. Expect this to decrease in
coverage after sunset before the next shortwave approaches from
the Mid Mississippi Valley and brings the next wave of activity.
Original Discussion...
Abundant cloud cover from a decaying MCS has served to limit
coverage of showers and thunderstorms across the area this
afternoon. We did see a few pockets of thunderstorm activity,
including Northeast Ohio where the lake breeze has provided
additional support. Thunderstorms today have been efficient rain
producers with rates of 3-4 inches per hour. Fortunately we have not
had problems with training storms yet but that will continue to be a
concern while this very warm and moist airmass remains in the
region.
Clouds have been clearing behind the remnants of the morning MCS
across Indiana and western Ohio. Temperatures will gain a few more
degrees late this afternoon with some sites reaching the low 80s
with dewpoints solidly near 70 degrees. We are seeing a cu field
form but only a few showers re-develop so far. Some larger
scale subsidence is still in place but the HRRR along with other
high resolution models do show some scattered thunderstorms
trying to develop along this boundary in the next couple hours.
Model soundings show the cap trying to erode through 7 PM with
ML CAPE values of 500-1000 J/kg where skies have cleared. With
20-30 knots of shear in the 0-6km layer will need to keep an eye
on any thunderstorms that develop but this should be a brief
window as storm strength should decrease towards sunset.
The remainder of the near term forecast still looks active into
Sunday night. The next piece of shortwave energy is expected to lift
through the Ohio Valley and enhance lift along a warm front
overnight. A 35 knot low level jet will be focused from Cincinnati
to wards Columbus with several high resolution models depicting rain
filling in along a west to east oriented boundary from Central
Ohio to at least the Route 30 corridor. The amount of thunder
with this activity is not entirely clear yet but expect to see
at least scattered activity. Upstream activity in Illinois and
Kentucky could be a disruption with this activity so will still
need to monitor evolution. In general the airmass is very moist
with PW values approaching 2 inches and a deep warm cloud
depth. 1-2" inches of rain is possible where this activity sets
up overnight with locally higher amounts possible if there is
more deep convection and training. This may warrant the need for
flooding products, especially if heavier rain falls in urban
areas.
Broad low pressure at the surface and aloft will ride northeast
along the stalled frontal boundary across the southern Great Lakes
Region on Sunday. Southern counties could see a break in the
rain for a few hours in the morning but expect showers and
thunderstorms to fill back in during the afternoon with the
moisture rich axis overhead. The greatest concern through Sunday
will be heavy rainfall and WPC has the entire area in a Slight
Risk of excessive rainfall either overnight or on Sunday. Most
of the area can expect between 1-2 inches of rain but locally
higher amounts are expected where thunderstorms or training
occur. Confidence was not high enough to go with a flood watch
but may be considered still if we do receive a solid round of
heavy rain overnight. Muggy conditions will persist on Sunday
but temperatures will struggle to surpass 80 degrees with clouds
and showers filling in. The better forcing and deeper moisture
finally starts to shift east on Sunday night with pops finally
dropping off from west to east.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
Expansive upper trough sprawling northeast to southwest from the
Northeast US into the Ohio Valley will remain over the forecast area
to begin the short term. Showers and thunderstorms remain spread out
across the region through Monday evening. The surface low pressure
and upper trough will exit eastward as mid level ridging attempts to
build in across the Lower Ohio Valley by late Monday night. This
will allow for rain chances to dissipate by Monday evening with low
chances for precipitation on Independence Day. As the upper trough
exits our area and high pressure builds in, cloud cover will
gradually clear Monday night. Expect a mostly sunny sky on Tuesday
and mainly clear conditions Tuesday night.
High temperatures will be near normal on Monday as they rise into
the upper 70s to low/mid 80s. Overnight lows Monday night will also
be seasonable in the low to mid 60s. As surface high pressure builds
south of our area Tuesday, warm air and moisture advection will
allow for dew points to rise into the mid 60s and highs in the mid
to upper 80s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
High pressure will remain over the area on Wednesday which will give
way to another hot day across northern Ohio. Afternoon highs will
approach if not hit 90 degrees across Northwest Ohio. Elsewhere,
afternoon highs will climb into the mid to upper 80s. Surface high
pressure and the mid-to-upper level ridge will exit east by
Wednesday night as another deep upper level trough and surface cold
front enter the region from the west. The surface cold front will
move east across the forecast area during the day Thursday giving
way to our next round of showers and thunderstorms. The lower Great
Lakes region will remain under the control of the upper trough which
will allow for showers and storms to linger over the area through
the end of the week before another high pressure with drier air
moves in from the west behind it. High temperatures take on a
cooling trend through the first part of the long term as the cold
front moves across the area. Afternoon highs in the mid to upper 80s
Wednesday and Thursday become mid to upper 70s by Friday and
Saturday. Overnight lows will take on a similar trend, beginning in
the mid 60s and ending in the upper 50s.
&&
.AVIATION /00Z Sunday THROUGH Thursday/...
Difficult, low confidence TAF forecast in terms of timing the
showers and thunderstorms and the drops in cigs and vis
associated with them. Widely scattered showers and storms this
evening could produce brief MVFR before about 02Z, mainly at
TOL, FDY, and CAK. Covered these with a TEMPO, but they are low
confidence. The confidence is more medium that a fairly
widespread area of showers and embedded thunder will move
eastward through the region tonight lowering cigs and vis to
MVFR at times, with occasional IFR possible but lower confidence.
ERI may miss most of this wave, but all other sites should see
longer periods of MVFR late tonight as these showers and
thunderstorms move west to east across the region. The lower
cigs and periods of MVFR will continue Sunday morning, but the
rain should become much more scattered in coverage before the
next wave of showers and thunderstorms moves through Sunday
afternoon and evening. This widespread precipitation will also
bring longer periods of MVFR Sunday afternoon and evening. IFR
is not out of the question, but capped at MVFR for now due to
uncertainty. Kept fog out of the TAFs tonight due to clouds and
precipitation moving back in, but there could be some patchy fog
where brief clearing occurs.
Winds will generally be SW at 5-10 knots through the TAF period.
Outlook...Non-VFR possible in scattered to widespread showers
and thunderstorms through Monday. Showers and thunderstorms
will be most numerous Sunday afternoon and evening. Non-VFR may
return again in isolated to scattered showers and thunderstorms
on Tuesday and Wednesday afternoons.
&&
.MARINE...
No periods of concern regarding marine conditions outside of brief
windows of gusty winds and higher waves in strong showers and
thunderstorms this weekend. A warm front will lift north across the
lake tonight followed by a cold front overnight Sunday into Monday.
Southerly flow less than 10 knots will be favored ahead of the cold
front with northwesterly flow between 5 and 15 knots behind the
front on Monday morning. High pressure will build south of the lake
Tuesday into Wednesday which will allow for winds to become
southwesterly between 5-10 knots through mid week.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC/Garuckas
SHORT TERM...KEC
LONG TERM...Iverson
AVIATION...Garuckas
MARINE...Iverson
Area Forecast Discussion
National Weather Service Cheyenne WY
414 PM MDT Sat Jul 1 2023
.SHORT TERM...(This evening through Monday night)
Issued at 300 PM MDT Sat Jul 1 2023
The main forecast challenges today deal with the limited convective
threat over the next several afternoons and the return of hot
temperatures for tomorrow and Monday.
We are enjoying a brief reprieve today from the widespread
convective activity of the last 10 days, but the atmosphere isn`t
quite ready to give up on producing storms entirely. Satellite shows
a nice circulation in the high cloud cover over central Nebraska
associated with yesterday`s shortwave trough sliding off to the
east. The cumulus field is suppressed over far eastern Wyoming and
western Nebraska collocated with the subsidence region on the
backside of the shortwave. Meanwhile, another weak shortwave is
riding over the top of the strong SW CONUS ridge this afternoon,
currently moving across Montana and northwest Wyoming. This is
nicely visible on water vapor imagery as the vorticity advection
helps to kick off a few showers and thunderstorms across those areas
this afternoon. As the subsidence moves off to the east over the
next few hours, we may be able to see a few more widely scattered
storms bubble up. The most favorable area this afternoon is in the
central and northern Laramie range where instability is the
greatest. HiRes models continue to show scattered showers and storms
also pushing across Carbon county through the evening hours, mainly
forced by the shortwave aloft. Thus, increased PoPs through midnight
tonight in these areas, but anything that does push through will be
limited, producing brief rainfall and possibly small hail and gusty
winds.
The broad ridge over the southwest will expand northeastward on
Sunday, beginning a brief warming trend. 700-mb temperatures warm to
about +12C on average across the area, supporting highs mostly in
the 80s to possibly low 90s in the typical hotter spots. The weak
shortwave passing through tonight also tries to drag the dryline a
little further east, dropping dewpoints a bit, though HiRes models
differ significantly in just how much of a drop will occur. Modest
instability and fairly steep lapse rates again may allow for another
round of isolated to widely scattered shower and thunderstorm
activity, though shear profiles remain fairly weak. The main
potential area looks like the higher terrain of southeast Wyoming
eastward to the southern panhandle. Nudged PoPs upward in this area
so that at least a chance for precipitation is mentioned, though the
drying trend could choke off precipitation, similar to what the
latest HRRR guidance is showing.
Further warming is likely Monday with better confidence in the
dryline advancing well to the east, approaching the eastern border
of the CWA. This results from weak lee cyclogenesis on the leading
edge of a strong trough smashing the ridge down from the north.
Models show a surge in warm air advection ahead of the cold front,
leading to 700-mb temperatures climbing to about +14C to even +16C.
With westerly downslope winds aiding warming, went a little more
aggressive on the warm temperatures Monday afternoon with a 50%
blend of the NBM 90th percentile. Looking at more widespread 90s,
with some mid 90s likely in the hot spots. Even Cheyenne will have a
shot at 90, but kept the official forecast just below for now.
Afternoon cloud cover and convective activity could put a cap on the
high temperatures a little earlier, so will monitor that in the
coming days. As the cold front pushes down from the north, expect
another burst of convection Monday afternoon traversing west to east
across the area. With inverted-v soundings showing up in the
forecast and cloud bases potentially above the freezing level, we
may have to watch for a dry microburst threat from this activity.
.LONG TERM...(Tuesday through Saturday)
Issued at 300 PM MDT Sat Jul 1 2023
Main Weather Highlights:
1) There is a Slight Risk for organized severe thunderstorms
across portions of SE Wyoming and the Nebraska Panhandle on
Tuesday.
2) Cooler temperatures expected across the region on Wednesday
behind a passing cold front
3) Potential for severe thunderstorms to impact portions of SE
Wyoming and the Nebraska Panhandle Thursday.
4) Staying unsettled toward the end of the week into next weekend.
Daily rain and thunderstorms chances possible.
Overview: Signals are emerging between model runs for the potential
for some organized severe weather to impact portions of SE Wyoming
and the Nebraska Panhandle on Tuesday afternoon into the evening.
The Storm Prediction Center has already highlighted these areas in a
Day 4 Slight Risk. Behind the storm activity expected on Tuesday,
cooler temperatures are likely in the wake of a cold front that will
push through the region Tuesday night. This should only last for one
day as temperatures rebound on Thursday with the threat of more
shower and thunderstorms by the afternoon hours. This unsettled
pattern looks to continue into next weekend with a shift toward a
more monsoon-like pattern begins to take shape.
Discussion: Synoptic setup on Tuesday is becoming more defined
regarding the severe weather potential across SE Wyoming and the
Nebraska Panhandle. By the early morning hours, a retreating dryline
will retrograde across eastern Wyoming as strong easterly flow
begins to advect better low level moisture into the region. This
dryline should push as far east toward Laramie and a northward
moving warm front will settle around the North Platte River Valley
by the afternoon hours. Strong SE flow will pump good low level
moisture into a warming and gradually growing unstable airmass
within the warm sector. One potentially limiting factor as of now
are rather marginal lapse rates being shown by most long range
models may limit the large hail threat, but adequate 0-6km shear
around 45kts will be enough to support rotating updrafts and
supercell thunderstorms. Heading toward the late afternoon and early
evening, the GFS develops the Chugwater Cyclone ahead of the
advancing cold front. In response, 0-1km helicity values jump up to
around 300m^2/s^2. Any ongoing discrete storms in this environment
could have a window to produce tornadoes. Additional development may
occur along the leading edge of the frontal boundary in the form of
thunderstorm clusters that may bring a straight line wind threat
primarily for the Nebraska Panhandle during the overnight hours.
Post FROPA CAA on the winds of NW flow will keep the area well below
normal temperatures on Wednesday. Some locations may struggle to
get out of the 50s on Wednesday while most areas see temperatures in
the low to mid 60s. NW flow will persist into Thursday and with some
rebounding in temperatures and a return of low level moisture and a
few embedded shortwaves within the flow aloft, there is the
potential for some organized thunderstorms to develop across the
region on Thursday, but details regarding the parameters are too far
out to assess a risk level at this time. The overall weather pattern
looks to remain on unsettled as a high pressure sits over central
Texas and with an incoming trough, a moist and almost monsoon type
pattern looks to develop which would keep daily rain chances in the
forecast heading into next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 412 PM MDT Sat Jul 1 2023
Ridging aloft will produce nearly clear skies through the period.
Surface pressure gradients will be sufficient to produce wind
gusts to 22 knots across the Wyoming terminals until 01Z, and to
25 knots after 15Z Sunday.
&&
.FIRE WEATHER...
Issued at 300 PM MDT Sat Jul 1 2023
Minimal fire weather concerns through the weekend, but hot, dry,
and breezy conditions are likely Monday. This afternoon is
relatively cool and most with breezy northwest winds across the
area. A few scattered showers and storms are likely this afternoon
and evening may bring locally gusty winds and small hail. Warmer
temperatures are expected Sunday with breezy conditions and RH
below 20% possible in the lower elevations of Carbon county.
Another round of widely scattered showers and storms is possible
Sunday PM.
Heading into Monday, temperatures climb several degrees above
average with gusty westerly winds expanding in coverage. Humidity
between 15 and 20 percent is likely along and west of the I-25
corridor. AFternoon convection Monday may produce gusty and
erratic winds. However, fuels remain in greenup status so no fire
weather headlines will be needed. A cold front will push through
Tuesday and bring a return of cooler and wetter weather.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MN
LONG TERM...AW
AVIATION...RUBIN
FIRE WEATHER...MN
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
618 PM CDT Sat Jul 1 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Sunday night)
Issued at 217 PM CDT Sat Jul 1 2023
The complex of showers and storms to the north of the area has
produced a mesoscale outflow boundary that is moving south and was
roughly located south of a Hillsboro to Hamilton to San Angelo line
at 2PM. This boundary could spark off additional isolated showers and
storms through sunset as it moves into far northern areas of the
CWA, near Llano and Burnet Counties, and possibly into the far
northern Gillespie, Kerr, and Edwards Counties. Farther south, a few
CAMs indicate the possibility of isolated showers during peak heating
late this afternoon across eastern areas of the Hill Country and
I-35 corridor. All of this activity should wane after sunset.
Attention turns upstream for convective development that is
beginning across West Texas. As indicated in the morning update, a
few of the 12Z CAMs are more bullish with an upstream complex of
storms toward Midland and the Big Bend making it into the southern
Edwards Plateau, western Hill Country, and Rio Grande late tonight.
This will be assisted by a mid and upper level shortwave in the
weakness splitting ridges to the west and east. However, not all CAMs
are indicating the complex makes it, and recent runs of the HRRR and
12Z Texas Tech WRF weaken and dissipate the storms before reaching
the area. We will hold PoPs in the 30-40% range across the northwest
CWA for late tonight. If storms do make it, a few marginally severe
storms will be possible, with damaging wind gusts the primary threat,
as well as some isolated pockets of heavy downpours.
On Sunday the weakness stretches from northeast Texas southwest into
the Edwards Plateau and Big Bend. The better rain chances should
remain closer to the axis, clipping far northern areas of the CWA.
With lower heights and additional cloud cover, high temperatures
tomorrow are forecast to be slightly cooler than today.
&&
.LONG TERM...
(Monday through Saturday)
Issued at 217 PM CDT Sat Jul 1 2023
South-Central Texas from early to midweek will remain positioned
under a minor weakness aloft or saddle point between the mid-level
ridging centered across the eastern Gulf of Mexico and over the
Desert Southwest. Despite lower 500 mb heights, temperatures will
remain persistent and a bit above average where afternoon highs are
to climb into the mid to upper 90s for most while overnight lows
remain steady in the mid to upper 70s. Rain chances look to remain
lowest on Monday and Independence Day but with the weakness aloft
along with near average moisture, a stray pop-up shower or storm may
be possible. Wednesday into late week likely will see an uptick in
the onshore south-southeasterly flow coming off the Gulf. This will
help promote the stronger inland progression of the seabreeze and the
advection of slightly above average PWATs into the eastern half of
the CWA. Isolated to scattered convection will trend within the
forecast across our eastern half of the CWA with Thursday offering
the greatest areal coverage. Given the greater low-level moisture,
we`ll keep a close eye on the peak heat index values during each
afternoon. Locations, especially along/east of I-35, could eclipse
108 degrees with heat indices and this may prompt Heat Advisories
through mid to late next week.
The mid-level ridge centered across the Desert Southwest will also
be expected to gradually amplify and slide eastward by the end of
this week and into next weekend. This leads to our next round of
hotter temperatures and a downtrend of area rain chances. This
includes the potential for additional Heat headlines with progress
into the weekend.
&&
.AVIATION...
(00Z TAFS)
Issued at 618 PM CDT Sat Jul 1 2023
VFR conditions are expected to prevail at all terminals through the
period. A few showers and possibly a thunderstorm are possible in
the vicinity of DRT late this evening, but confidence is not high
enough for anything more than a VCSH mention at this time. Also, SAT
and SSF may briefly see MVFR cigs some time during the early morning
hours tomorrow, but confidence is too low for mention in the TAFs at
this time. Otherwise, expect a decent amount of mid and upper level
cloud cover with winds swinging between SE and SSW.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 100 77 99 77 / 10 10 0 10
Austin Bergstrom Intl Airport 98 76 97 77 / 10 10 0 10
New Braunfels Muni Airport 99 75 97 76 / 10 0 0 10
Burnet Muni Airport 97 75 96 76 / 30 10 10 10
Del Rio Intl Airport 98 78 97 79 / 10 40 20 10
Georgetown Muni Airport 99 77 97 77 / 20 10 10 10
Hondo Muni Airport 98 75 97 75 / 10 20 10 10
San Marcos Muni Airport 99 75 97 75 / 10 10 0 10
La Grange - Fayette Regional 98 77 96 77 / 10 0 0 10
San Antonio Intl Airport 99 77 97 77 / 10 10 0 10
Stinson Muni Airport 100 77 98 77 / 10 0 0 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...76
Long-Term...Brady
Aviation...Gale
Area Forecast Discussion
National Weather Service Memphis TN
946 PM CDT Sat Jul 1 2023
...New UPDATE...
.UPDATE...
Issued at 946 PM CDT Sat Jul 1 2023
Convection has ended across most of the Mid-South as of 9 PM but
a cluster of storms continues across southwest KY with another
batch farther east over central MO. A potent shortwave trough is
moving east into the Mid MS Valley, resulting in strong forcing
for ascent across the Lower OH Valley and maintaining a favorable
environment for convection. RAP analysis indicates a 40-45 kt jet
at 500 mb nosing into northeast AR which has enhanced deep-layer
shear this evening. Instability is expected to weaken somewhat
over the next couple of hours with convective inhibition
increasing as the boundary layer "cools". Thus, slight chance PoPs
look reasonable during the overnight period, mainly from northeast
AR into West TN, as the upstream convection over central MO moves
toward the area.
Additional showers and thunderstorms will develop by midday
Sunday. Coverage will likely be similar to (or slightly greater
than) today with another round of strong to severe storms
possible. Slightly cooler temperatures and dewpoints should yield
MLCAPE of 2500-3500 J/kg with 0-6 km bulk shear of 25-30 kts. This
should be sufficient to support additional multicellular storms
with the potential for a few supercells. Hail and damaging wind
appear to be the greatest threats through Sunday evening.
MJ
&&
.SYNOPSIS...
Issued at 259 PM CDT Sat Jul 1 2023
Strong to severe storms are expected to continue through this
evening with damaging winds and large hail the main threats. Heat
and rain return Sunday with heat index values likely to remain at
and below 105F in portions of the Mid-South. Otherwise, expect
the upcoming work week to be hot with daily rain chances.
ANS
&&
.DISCUSSION...
(This evening through next Friday)
Issued at 259 PM CDT Sat Jul 1 2023
Showers and storms continue to pop-up across various portions of
the Mid-South with the bulk of activity near northeast Arkansas
and the Missouri Bootheel. Right now, the greatest threat for
severe storm development is in the northern portions of the Mid-
South. Additional storms may develop this evening as the cap
breaks over TN / MS. Damaging winds and large hail are possible
through the evening hours.
Outside of thunderstorm development, the remainder of today will
be hot. 230 PM surface observations depict heat index values in
excess of 105 degrees through the majority of the Mid-South. Hot
and humid conditions will continue overnight with lows only
dropping to the upper 70s. Temperatures on Sunday will remain hot,
but overall heat index values will remain at and below 105F. A
Heat Advisory has been issued for areas along and south of the
Mississippi state border Sunday.
By Monday afternoon, a cold front will stall over the northern
portions of the Mid-South and stay in place through mid-week.
During this time, daily rounds of showers and thunderstorms are
possible. Overall, bulk shear during this time appears to remain
lack luster. However, ample instability will encompass the Mid-
South. Therefore, any storm that does form could become strong.
Long range models hint at a pattern change late Thursday as an
upper level trough moves over the Great Lakes Region. A cold front
will likely swing across the region with showers and storms
accompanying its passage. However, it is too early to tell the
details of this system. Overall, expect a warm week ahead with
daily chances of rain.
ANS
&&
.AVIATION...
(00Z TAFS)
Issued at 628 PM CDT Sat Jul 1 2023
Primary forecast challenge remains timing and coverage of TSRA.
Airmass west and south of MEM remains unstable, but flat or non-
existent cumulus field indicates a relatively strong convective
inhibition. As such, TSRA should remain north of MEM tonight.
From JBR eastward, a belt of stronger midlevel westerly winds and
weak convective inhibition will persists this evening.
An approaching upper trough over the plains will further weaken
convective inhibition over the Midsouth on Sunday. CAMs continue
to vary with timing of TSRA onset, given the continued instability
and tenuous convective cap from midmorning onward. For the TAFs,
timing of PROB30 TSRA followed peak heating Sunday afternoon.
Better timing for TSRA at TUP will be just beyond the valid TAF
period.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Heat Advisory from 10 AM to 7 PM CDT Sunday for ARZ035-036-048-
049-058.
MO...None.
MS...Heat Advisory from 10 AM to 7 PM CDT Sunday for MSZ001>017-
020>024.
TN...Heat Advisory from 10 AM to 7 PM CDT Sunday for TNZ088>092.
&&
$$
UPDATE...MJ
PUBLIC FORECAST...ANS
AVIATION...PWB
Area Forecast Discussion
National Weather Service Marquette MI
724 PM EDT Sat Jul 1 2023
.SHORT TERM...(Through Tonight)
Issued at 253 PM EDT SAT JUL 1 2023
Water vapor imagery and RAP analysis show mid-level troffing over
James Bay extending into the northern Great Lakes while a vigorous
shortwave is noted over Nebraska/KS. Although it was a quiet morning
across the fcst area, cu that began to form late morning quickly
developed into sct shra along the Lake Superior and Lake MI lake
breezes over the eastern fcst area shortly after noon. Even over the
w, a couple of shra have recently developed. So far, there has been
very little lightning with the convection. Out on Lake Superior,
considerable fog, including areas of dense fog, is noted on vis
satellite imagery. Some of this fog/stratus is making a slight
inland push from the shoreline areas. Temps at 18z are in the mid
70s to mid 80s F, but only 50s/60s F along Lake Superior. Under
fog/stratus, Copper Harbor is coolest at only 50F.
Latest SPC mesoanalysis shows mlcape on the order of 250-500j/kg.
This instability will continue to support sct shra/isold tsra
progressing southward with the Lake Superior lake breeze, and a few
more shra will probably develop over the interior w. With a lake
breeze off of Lake Superior, fog/stratus will begin to affect more
shoreline locations as the aftn progresses.
Isold convection will likely end before sunset. Development of land
breezes during the night will halt any inland push of fog/stratus
off of Lake Superior, especially over western Upper MI. However,
some patchy, shallow radiation fog may still develop. Over the e,
looks like there may be just enough of a n to nw wind to continue
fog/stratus expansion inland in addition to radiational fog
development farther inland. Fog may be locally dense. Expect min
temps generally in the upper 40s to mid 50s F.
.LONG TERM...(Sunday through Saturday)
Issued at 313 PM EDT SAT JUL 1 2023
By Sunday morning, the 500mb trough axis will be from around the
Chicago vicinity to east of James Bay with upstream ridging
approaching from the west. This ridge will provide the support for a
weak high pressure over Lake Superior and subsidence to suppress
most clouds and any precip chances for Sunday. 12Z CAM guidance
shows a lake breeze forming for Lake Michigan, but there is some
disagreement as to how far inland the lake breeze penetrates.
Despite the clear conditions, even the lower end of dew point
guidance only brings minimum RH values into the 40s, and with winds
mostly 10 mph or less, fire weather is not a large concern Sunday.
Monday looks to have fairly similar conditions as Sunday as
troughing advances to the Lower Great Lakes, though some additional
cloud cover may be expected as the ridging weakens and advances
eastward.
Unsettled weather arrives late Monday into Independence Day as a
deep trough (-13 dam anomaly per 12Z GEFS) advances through central
Canada. The Euro ensemble shows probabilities of Independence Day`s
precip totals exceeding a tenth of an inch at only a little better
than a coin flip in the west to 10 percent or less in the east.
However, the GEFS is far more enthusiastic about more notable rain,
with around 75 percent of ensemble members having July 4th precip
totals between a tenth and a half inch. With GEFS mean SBCAPE values
around 1000 J/kg around IWD and around 800 J/kg at SAW, some of
these showers may produce lightning, but uncertainty is still high,
so make sure your 4th of July plans include being weather-aware and
continue to monitor the forecast as details are refined over the
next couple days. Additionally, it would be advisable to dress
lightly as warm southwesterly flow aloft will help temperatures to
climb to near 90 in the interior.
The bulk of precipitation is expected to fall Wednesday as the cold
front is draped south from the parent low lifting into the Hudson
Bay. The operational GFS far exceeds its ensemble mean in QPF, with
nearly 3 inches of rain for the Marquette area by Wednesday night,
with only 1 other ensemble member above that value and the ensemble
mean just below an inch. The Euro and Canadian deterministics are
also above their respective ensemble means, but still around their
respective 75th percentiles at around an inch. There is still some
uncertainty in timing and location as the GEFS and Euro ensemble
spread in the locations of the parent low spans the entirety of far-
northern Ontario Tuesday night, however, it seems likely that a
wetting rain will occur for much, if not all, of the UP in the
midweek period.
Rain chances linger early Thursday, but the end of the week looks to
dry out as a surface high of around 1018mb per ensemble means
advances over the Upper Great Lakes. Beyond the end of the work
week, ensembles descend into chaos, but mean 500mb height anomaly in
the ensembles show a persistence of northwesterly to zonal flow with
troughing preferred over the central to eastern CONUS. This hints at
a continued active pattern of precipitation and slightly cooler
temperatures than average.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 724 PM EDT SAT JUL 1 2023
VFR conditions remain the rule over the region early this evening
along with light winds less than 10 knots. The tricky part of the
forecast remains the potential for fog development and/or advection.
KIWD will see some patchy ground fog developing after Midnight,
which will bring visibilities down to MVFR. While KIWD winds should
be calm overnight, any light breeze will attempt to advect fog from
Lake Superior into that TAF site, making IFR conditions a slight
possibility, but confidence in that happening is not high at this
time.
At KCMX and KSAW, expect fog over Lake Superior to infiltrate both
TAF sites later tonight, resulting in periods of IFR/LIFR
conditions. The fog will burn off rather quickly in the morning with
VFR conditions developing shortly after sunrise. KSAW may take a
little longer to reach VFR in the morning with weak upslope flow
developing. The VFR conditions will persist through the remainder of
the forecast.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 313 PM EDT SAT JUL 1 2023
With weak pressure gradients for much of the CONUS and Canada east
of the Rockies, winds will remain below 20 knots for the entire
forecast period. The highest winds will be following a cold front on
Wednesday into Thursday, where wind gusts may briefly exceed 20
knots in some areas of north-central Lake Superior, especially on
elevated platforms. With the lack of winds, the areas of dense fog
over Lake Superior will persist through at least Sunday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Dense Fog Advisory until 11 AM EDT /10 AM CDT/ Sunday for LSZ162-
240>244-248>251-263>267.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...GS
AVIATION...RJT
MARINE...GS
Area Forecast Discussion
National Weather Service Morristown TN
932 PM EDT Sat Jul 1 2023
...New UPDATE...
.UPDATE...
Issued at 927 PM EDT Sat Jul 1 2023
Showers and storms have come to an end across the forecast area.
Will keep slight chance POPs in through the night as we keep some
elevated instability in place but most locations will be dry.
Hourly temps were running way too high due to showers and storms
that rolled through earlier but everything is back on track now.
&&
.SHORT TERM...
(This evening through Sunday)
Issued at 240 PM EDT Sat Jul 1 2023
Key Messages:
1. Isolated damaging winds and marginal hail potential across the
Plateau and southern half of the Tennessee valley through early
this evening.
2. More widespread severe storms with damaging winds and hail
possible for late Sunday and evening.
Discussion:
Through this Evening, a thunderstorm complex associated with a
weak short-wave riding on top of the upper ridge. MLCAPES are
between 2000-2500 over much of the current severe thunderstorm
watch. Main concern is damaging winds as DCAPES are between
1200-1300. Hail CAPES are 600-700 but high freezing levels will
limit hail production but will help with potential of strong
downbursts winds.
Isolated damaging winds and marginal hail possible across the
Plateau, southern half of the Tennessee valley, and Cherokee and
Clay counties through early evening.
For tonight, latest HREF and HRRR suggests a break in the
convection. Where rain occurs, patchy fog is possible overnight.
For Sunday, an upper trough moves across the mid-west into the
Ohio valley. A 60-70kts upper jet core will move across the Ohio
valley placing the lower Ohio valley and upper Tennessee valley
under the favored right entrance region of the jet. The upper jet
also strengthens the 850mb jet to 25-30kts by late in the day.
The jet dynamics will increase the forcing along a surface trough
across Kentucky into middle Tennessee in the late afternoon.
Models show a fairly unstable environment along and ahead of this
boundary with MLCAPES of 2500-3000. HREF shows mean CAPES of 2500
as well.
The wind field will also provide some organization to the
convection with effective shear up to 25-30kts. DCAPES are once
again quite high with values of 1200+ due to mid-level dry air.
Model soundings also show mid- level lapse rates of 6.5 to 7
degrees. Decent mid- level lapse rates and effective shear will
help support better hail residence time and hail growth.
Greater coverage and intensity of severe storms are expected late
in the day Sunday. SPC currently has the entire area under a
slight risk.
HREF shows PWs of 1.4 inches. Flash flood potential is marginal
but will need to watch for any training of cells.
&&
.LONG TERM...
(Sunday night through next Saturday)
Issued at 240 PM EDT Sat Jul 1 2023
Key Messages:
1. Showers and thunderstorms will be numerous Sunday night into
Monday with a weak cold front moving through. Then more scattered
convective activity for a few days before another weak front
approaches Friday. Strong storms possible Monday in southern parts
of the area. Daytime heating each day may produce isolated strong
storms through Thursday.
2. Temperatures close to seasonal normals expected Monday through
Thursday, then slightly cooler Friday and Saturday with more cloud
cover, more precipitation and weak front.
3. An upper trough moving into Great Lakes and Ohio Valley Thursday
into Friday will bring a front into the eastern Tennessee Valley
mainly Friday and Friday night. There will be an increased chance of
thunderstorms and these may become strong to possibly severe.
Discussion:
Upper trough moving into the Great Lakes and Ohio Valley will move a
weak cold front this way Sunday night and Monday. The front stalls
or gets hung up over southern Tennessee Monday night into Tuesday
and then gradually dissipates Tuesday and Tuesday night. As the
first front weakens Tuesday night, weak high pressure builds in at
the surface and aloft by mid week and convection becomes more
diurnal. Thursday a new front approaches the Ohio Valley and this
front, ahead of another trough moves into the eastern Tennessee
Valley region Friday. Rain chances become likely with showers and
thunderstorms Thursday night or early Friday. Friday night and early
Saturday the front will move slowly through and should be in North
Carolina by later in the day Saturday. The GFS is faster with the
front and deeper with the trough so Saturday may be dry if this
model is more correct. Rainfall amounts each day will vary widely
depending on where storms develop but will average around 0.25 to
0.50 inch Sunday evening to monday evening with localized higher
amounts that may produce localized flooding. For Monday evening the
to Tuesday evening the rainfall amounts should be lower. Amounts for
the 5 day period ending Thursday at 12Z are forecast to be 1 to 2
inches but much of that should come in the first 2 days ending
Monday evening.
&&
.AVIATION...
(00Z TAFS)
Issued at 722 PM EDT Sat Jul 1 2023
VFR conditions are forecast through the rest of the night. The
only uncertainty over the next few hours is whether or not a gust
from moving northeast through northeast TN reaches TRI. Will
amend if needed. Otherwise, more showers and storms again
tomorrow, which could produce MVFR conditions. Gusty afternoon
winds at TYS and TRI from out of the west at 18kts.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 96 73 95 72 / 70 30 50 50
Knoxville McGhee Tyson Airport, TN 92 72 92 71 / 40 30 50 60
Oak Ridge, TN 92 71 91 70 / 50 40 60 70
Tri Cities Airport, TN 89 68 89 68 / 30 30 50 60
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...
LONG TERM....TD
AVIATION...