Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/04/21
Area Forecast Discussion
National Weather Service La Crosse WI
1022 PM CDT Thu Jun 3 2021
.SHORT TERM...(This evening through Friday)
Issued at 215 PM CDT Thu Jun 3 2021
A shortwave trough will move southeast through the area tonight.
The RAP surface-based CAPE is up to 500 J/kg this afternoon and
then gradually lowers to less than 100 J/kg tonight. The effective
0-6 km shear climbs into the 25 to 35 knot range by 04.00z and
then continues through the early evening. This shear then falls
to less than 30 knots overnight. However, with the storms being
primarily elevated, it looks like this shear may not be felt by
any of the storms. As a result, just stayed with isolated to
scattered showers and storms. If any storm happened to become
strong, gusty winds would be the primary threat.
On Friday, high pressure will build across the area. Soundings
suggest that we will mix up into the 750-800 mb range. As this
occurs, dew points will likely fall into the lower to mid-50s. There
may be even a few upper 40s. These dew points are dry enough that
they will keep the heat index from getting out of hand. In addition,
they may also help the temperatures in the river valleys to over
achieve some.
.LONG TERM...(Friday night through Thursday)
Issued at 215 PM CDT Thu Jun 3 2021
Record or near record heat builds in for the weekend with
continued above normal temperatures into next week with on and off
shower and thunderstorm chances Sunday night through Thursday.
582dm heights build in for the weekend and combined with brisk
southwest winds and relatively low dewpoints these conditions
support warm temperatures in the 80s to lower 90s for the local
forecast area. The 850mb thermal axis stretches from the Dakotas
into Minnesota and generally stays there. Temperatures from 850mb
to 500mb are generally 1 to 3 standard deviations above normal per
the NAEFS, with the stronger above normal signal to our west
where the thermal axis is. The probability for temperatures in the
90s is 85 to 99% for Saturday per our National Blend Model.
Recently, we have had a 2 to 4 degrees cool bias from our local
statistics. Our current forecasts are mostly in the 90 to 95th
percentile compared to all other guidance, so this is a good
start. Although grasses are green, crops are just getting started,
so transpiration should be more limited compared to a month or
two from now. Dewpoints in the 60s and brisk southwest winds
should aid in temperatures climbing to near record or in some
cases record levels in the 80s and 90s.
The minimum relative humidity should range from 30 to 45 percent
Saturday and Sunday combined with southwest winds 10 to 15 mph
with gusts to 30 mph Saturday and Sunday during the afternoon.
Northeast Iowa and southwest Wisconsin have been dry over the last
couple of weeks compared to areas farther north. Most areas have
greened up significantly with mainly tall grasses or pine needle
areas prone to higher fire weather concerns.
A series of shortwave troughs will track across the northern U.S.
and by Sunday night, one will be strong enough to push a cold front
southward toward the forecast area by around 06Z, however it is
uncertain how far south the front will make it before it returns
north. Meanwhile, 500mb low pressure over the Southern Plains is
progged to lift north. Depending on the frontal timing, this
moisture will try to advance northward as well. The current GEFS
ensembles mostly clip our area to the southeast Monday with a push a
little farther north Tuesday, with better chances for rain
Wednesday. With a front to the north, the showers and thunderstorms
there and attendant boundaries may also play a role in where storms
develop next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1021 PM CDT Thu Jun 3 2021
Main taf concern are potential for showers impact both RST/LSE taf
sites tonight. A disturbance embedded in the northwest flow aloft
will track into central Wisconsin tonight. At this time...the better
moisture convergence/lift will be east of the taf sites and any
shower development is expected to mainly be along and east of the
Mississippi River. At this time will leave mention of showers out of
the tafs. The other concern is low level wind shear at both taf
sites. Wind speeds increase aloft tonight and allow for low level
wind shear to develop and continue to around 12 to 14z Friday. VFR
conditions will prevail into Friday...as surface ridge axis centered
along the Minnesota/Wisconsin border provides mostly sunny skies
Friday.
&&
.CLIMATE...
Issued at 215 PM CDT Wed Jun 2 2021
It continues to look like we will have the potential of seeing some
high and warm low records either tied or broken. We put together a
web page which has the record highs and warm lows from Friday into
the weekend. It also provides 90-degree climatology for several
location in our area. This page can be found at
weather.gov/arx/june2021heat
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Boyne
LONG TERM...Zapotocny
AVIATION...DTJ
CLIMATE...Boyne
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
1009 PM CDT Thu Jun 3 2021
.DISCUSSION...Air mass has stabilized over the region behind the
convection that has moved offshore with temperatures in the upper
60s to lower 70s. SPC mesoanalysis shows MLCAPE values from
1000-1500 j/kg over the offshore waters. The outflow boundary just
past the near shore waters may drift back toward the coast during
the overnight hours. Deep moisture will still be in place over
the coastal plains. The 50H low will remain over the Edwards
Plateau while the 85H low will be to the southeast over the Rio
Grande Plains. Models show low level convergence will increase
along the coast overnight with additional upper level support from
an upper level jet streak moving northeast into the region. Latest
Hi-res models are not optimistic with regards to redevelopment
over the coastal plains overnight, but the environment will be
favorable for storms to reform later tonight. Kept the Flash Flood
Watch going for the coastal plains, but cancelled the watch for
the western 4 counties. Showers may redevelop overnight, but the
threat for heavy rainfall will be to the east.
&&
.PREV DISCUSSION... /Issued 654 PM CDT Thu Jun 3 2021/
AVIATION...00Z TAFs
Outflow boundary from thunderstorms has made it to the coast with
the stronger storms from Port Aransas to Port O`Connor moving to
the northeast. Showers will affect the coastal sites through 03Z
with thunderstorms possible until 02Z. MVFR ceilings/vsbys will
occur for the coastal plains with periodic IFR ceilings/vsbys with
the stronger storms along the coast. A brief improvement will
occur late this evening with vsbys while MVFR ceilings persist.
The outflow boundary is expected to stall over the near shore
waters early this evening and drift back toward the coast by
the overnight period. Expect additional showers and storms will
form near the coast and affect the coastal plains from the
early overnight period through Friday morning, especially over
the Victoria Crossroads. MVFR ceilings/vsbys will be prevalent
with IFR ceilings/vsbys expected with the stronger storms.
Convection may linger into the afternoon hours but confidence
is low at this time. For the Brush Country, post outflow boundary
low clouds will affect the LRD area early this evening with IFR
ceilings. Expect the ceilings will lift to MVFR late this evening.
Scattered showers will move into the region during the overnight
period, but the threat for heavier rainfall and thunderstorms may
be east of this area. MVFR ceilings are expected to persist over
the Brush Country during the overnight into Friday.
PREV DISCUSSION... /Issued 446 PM CDT Thu Jun 3 2021/
SHORT TERM (Tonight through Friday Night)...
The ECMWF/NAM deterministic runs predict increasing upper forcing
during the period associated with the approaching upper
trough/low. NAM predicts PWAT values well above normal during the
period. The GFS, and to a lesser extent the RAP, maintains a weak
quasi-stationary boundary across the CWA overnight, while the NAM
keeps it farther south. Expect scattered/numerous convection
during the period. The RAP and NAM predict thermodynamic profiles
conducive to efficient rainfall production (warm nearly saturated
0-4km layer and moderate CAPE) after 06z Friday, with significant
0-6km vertical shear as the caveat. Likely that rainfall totals
over many areas exceed hourly FFG values. Concur with WPC
regarding the Marginal/Slight Risk over the CWA tonight/Friday.
Coordinated with BRO WFO and issued a FFA for all of the CWA for
the 00-12z Friday period. It will likely need to be extended
beyond 12z Friday yet will defer to the mid shift.
LONG TERM (Saturday through Thursday)...
Rain chances will continue through the extended period, but may some
drying by the end of next week.
A mid/upper level low will meander across TX through Saturday with
embedded short waves rounding its base and moving across S TX.
Models prog the environment to be unstable with minimal CIN and
ample amount of moisture. PWATs are progged to range from 1.6 inches
across the west to 1.9 across the northeastern portions of the CWA.
Models are also hinting at a weak boundary/convergence zone across
the northwestern CWA Sat morning and increasing diffluence aloft.
All of these features combined will be conducive for sct to num
showers and thunderstorms on Saturday with possibly a few strong
storms. QPF values are not quite as high for Sat as previous runs,
but the forecasted environment will have the potential for locally
heavy rainfall, especially across the Victoria Crossroads. The
Weather Prediction Center has a marginal risk for excessive rainfall
for the VCT area on Sat.
Slightly drier Sunday as the upper low axis shifts east of the area
and brings dry mid levels across S TX. Still enough moisture for iso
to sct convection with the better chances remaining across the VCT
area. Models prog another short wave embedded in the northwest flow
aloft to move southeast across the region Monday bringing another
round of convection. This pattern continues through the middle of
next week.
Warmer max temps Sunday through mid week combined with a humid
environment could lead to afternoon heat indices reaching 105 across
the western CWA. Monday may see heat indices ranging from 105 to
108.
MARINE...
The combination of a developing upper level low pressure system
and copious moisture will contribute to scattered/numerous showers
and thunderstorms late tonight through Friday. A weak to
moderate, to sometimes moderate, onshore flow can be expected
Saturday through the middle of next week. Isolated to scattered
showers and thunderstorms will be possible daily.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 71 82 71 83 73 / 90 70 60 60 30
Victoria 69 81 70 82 70 / 90 70 70 80 50
Laredo 70 87 71 90 72 / 60 60 50 30 10
Alice 69 84 68 86 70 / 90 70 60 50 20
Rockport 72 84 73 84 74 / 80 70 60 60 40
Cotulla 71 86 70 88 72 / 60 70 60 50 20
Kingsville 71 82 70 85 72 / 90 70 60 50 20
Navy Corpus 73 82 74 83 76 / 80 70 60 60 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch until 7 AM CDT Friday For the following zones:
Aransas Islands...Bee...Calhoun Islands...Coastal Aransas...
Coastal Calhoun...Coastal Kleberg...Coastal Nueces...
Coastal Refugio...Coastal San Patricio...Goliad...Inland
Calhoun...Inland Kleberg...Inland Nueces...Inland Refugio...
Inland San Patricio...Jim Wells...Kleberg Islands...Live
Oak...Nueces Islands...Victoria.
GM...None.
&&
$$
TMT/89...SHORT TERM
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
959 PM CDT Thu Jun 3 2021
.UPDATE...
Expecting some stabilization behind the convection across South
Central Texas tonight. We have lowered the POPs for the rest of
tonight. Short term models still show some chance for rain
especially along the Rio Grande.
&&
.PREV DISCUSSION... /ISSUED 635 PM CDT Thu Jun 3 2021/
AVIATION...
For the Austin and San Antonio terminals the rain has nearly come to
an end for the evening. Ceilings have lifted to VFR and what rain is
continuing is very light and having no effect on visibility. Showers
may move over the airports for the next couple of hours, but will not
have any effect on flying category. Ceilings will lower to MVFR later
this evening and then to IFR overnight. Showers and thunderstorms
will develop again overnight and continuing through the day Friday.
Ceilings will only improve to MVFR Friday afternoon.
At DRT, they are currently VFR and will remain that way through the
evening. There are isolated showers and thunderstorms in the area
and it possible that they move over the airport during the next few
hours. If any do, they will likely not change the category. The
ceiling will lower to MVFR later tonight and stay that way through
Friday morning. Showers and thunderstorms will be possible Friday
afternoon.
PREV DISCUSSION... /ISSUED 232 PM CDT Thu Jun 3 2021/
SHORT TERM (Tonight through Friday Night)...
What a wet day it has been across South Central Texas. While most
spots saw a good inch to inch and a half of rain some spots across
the Hill Country, Austin Metro, and then parts of Southern Bexar and
Wilson County have seen 3 to 4 inches of rainfall with localized
higher totals. This has caused issued with area low water crossings
with even just the quick 1/2 inch to 1.5 inches causing water to
flow over them due to the saturated ground.
The good news in the short term is that the mesoscale models are in
good agreement (and are decently supported by the global models)
that this activity should continue to work its way to the east and
south through the afternoon. The heaviest rain for the rest of the
day will be along the Coastal Plains with more light rain across the
I-35 corridor.
The PoP forecast for the short term is roughly based on the SPC
HREF, and while one would normally use that for severe weather, have
utilized it for our rainfall forecasts this go around, as no severe
weather is expected during the short term. In general the late
evening through the early overnight hours should be fairly quiet
with light rain ending. Have left 30-40 PoPs across the area, but
even these may be too high with the drying trend of the HRRR and
other models. The next round of rainfall for the area will begin
some time late tonight into Friday morning. The HREF members vary
with the NAM Nest showing precipitation redeveloping around 4am,
with most of the other models holding off until around 7am. The
Texas Tech WRF, which did a decent job with today`s round of
precipitation holds off redevelopment until late morning on Friday.
Have sided with the earlier onset of the precipitation here as it
seems to be the consensus of the high resolution models at this
time, but as we saw yesterday evening much can change in these
models, even over a 6 hour period so confidence in the timing is
low. What seems to be certain is another round of rainfall, this
time developing from the south and moving north across our area at
some point during the day on Friday.
Synoptically the upper low that has been plaguing us over the last
week will be to the Big Bend Region by 7am on Friday. This will help
to enhance the rain chances for the day on Friday and into Friday
night. The low will take its sweet time moving across the state with
it only reaching the Central Part of Texas by Saturday morning.
Unsurprisingly the synoptic models have the heaviest rainfall
occurring at different times over the short term, but they all
generally agree that tomorrow through Saturday will be another wet
period. The ECMWF continues to be the wettest of the models, while
the GFS focuses the heaviest rainfall late tomorrow and into
Saturday. The NAM on the other hand has much of the heavy rainfall
during the day tomorrow.
Lets talk messaging and impacts to wrap this up. First off with the
rains today and over the last several days much of the area has seen
anywhere from 2 to 6 inches of rain. As was demonstrated today, even
a quick inch in urban areas can cause low water crossings to flood.
Localized flooding will continue to be the main concern with the
Weather Prediction Center introducing a slight risk of excessive
rainfall for Friday. Think that a Flash Flood Watch is a wise choice
now that we are very well primed for more flooding. Have decided to
hold off for this afternoon with the current system moving out.
Future shifts, either the evening once things calm down, or the
overnight shift will reconsider the need for a Flash Flood Watch and
possibly issue one for parts of the area. While the rivers have not
seen big impacts thus far low water crossings have been with over
100 still closed on ATXfloods, and 17 closed across Bexar county on
Bexarflood. These will continue to be the main hazard so always
remember Turn Around, Don`t Drown. This is honestly a great weekend
to just make a 3 day weekend, stay home and off the roads, watch
your favorite streaming service, and enjoy the rain outside from the
safety of your home.
LONG TERM (Saturday through Thursday)...
An upper level low will be centered over Central Texas on Saturday
into Sunday with a lower level flow off the Gulf of Mexico and an
unseasonably moist airmass over our area. Upward forcing continues
the scattered to numerous showers and thunderstorms with the main
threat being heavy rains causing flooding due to moist soils from
earlier rains. The greatest threat for heavy rains and flooding will
be from the Hill Country across the I-35 corridor to near the
Coastal Plains. Rainfall amounts of 1 to 2 inches with isolated
amounts of 4+ inches can be expected across those areas. Cannot rule
out a strong storm or two with gusty winds possible.
The upper level low gradually lifts to the northeast while weakening
into a shear axis across eastern Texas early to middle part of next
week. However, a moist airmass remains over area due to lower level
flow off the Gulf of Mexico. The chances of showers and thunderstorms
continue, although, with time become mainly diurnally forced by
solar heating by the middle of next week. The threat for heavy rains
will become much more localized, as well.
Due to clouds and rain, high temperatures will remain below normal,
though trend closer to normal by later next week. Low temperatures
should be around normal.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 66 79 67 80 68 / 40 80 60 80 50
Austin Bergstrom Intl Airport 66 79 67 80 68 / 50 80 60 80 50
New Braunfels Muni Airport 65 80 68 81 69 / 40 80 60 80 50
Burnet Muni Airport 64 78 66 78 66 / 40 80 50 70 40
Del Rio Intl Airport 69 83 69 85 71 / 50 60 40 30 10
Georgetown Muni Airport 65 78 67 80 67 / 40 80 50 80 50
Hondo Muni Airport 65 80 67 81 68 / 40 80 60 60 30
San Marcos Muni Airport 66 80 67 81 67 / 40 80 60 80 50
La Grange - Fayette Regional 69 82 70 83 70 / 60 80 60 80 50
San Antonio Intl Airport 66 79 68 80 69 / 40 80 60 80 40
Stinson Muni Airport 67 81 69 82 69 / 40 80 60 70 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...05
Long-Term...Platt
Area Forecast Discussion
National Weather Service Houston/Galveston TX
717 PM CDT Thu Jun 3 2021
.AVIATION [00Z TAF Issuance]...
Quite a bit of activity ongoing across SE TX at this time as a
strong shortwave moves through the area. Will keep the mention
of TSRA/VCTS in for a few more hours for most sites...but will
expect the activity to become more stratiform in nature before
coverage decreases further by midnight. IFR/MVFR CIGS are fore-
cast to develop overnight through early tomorrow (Fri) morning
during this brief lull from this rains. Short-range models are
indicating another round of scattered showers/storms moving in
from the W/SW around mid/late tomorrow morning (12-15Z) as yet
another shortwave moves into the region. Coverage should fill/
become fairly widespread tomorrow afternoon with both VIS/CIGS
hovering around MVFR. 41
&&
.PREV DISCUSSION... /ISSUED 404 PM CDT Thu Jun 3 2021/
SHORT TERM [Through Friday Night]...
Today is looking almost identical to yesterday with showers and
thunderstorms developing along the sea breeze. A shortwave ejecting
off of a deepening upper level low in West Texas will move across
our area into the evening enhancing the diurnally driven convection.
PWATs are over 2 inches this afternoon, so locally heavy rainfall
will be possible causing ponding along low lying areas. Based short
term PoPs towards the HRRR as it has been initializing fairly well
all day. Precipitation will become largely widespread by the late
afternoon into the evening for most of the area but the immediate
coastline. May want to plan for longer commute times for the evening
rush tonight. There will be a lull in the precipitation late this
evening into tonight, but this won`t last long as scattered showers
and thunderstorms fills back in from west to east by day break as
yet another shortwave passes through the area. The upper level
trough becomes a closed low early Friday and begin its slow approach
to Southeast Texas through the day on Friday. There again remains a
chance of locally heavy rain through Friday evening. Grounds are
fairly well saturated from weeks of rainfall, so will need to watch
closely for any flooding concerns. The WPC has placed the western
half of the CWA in a Slight Risk of the area for Excessive Rainfall.
Total rainfall through Friday night will be around 1 to 3 inches
with locally higher amounts possible.
Temperatures through the short term will not vary much thanks to
overcast skies. Low temperatures tonight will dip down to near 70,
then temperatures rise to near 80 in the afternoon tomorrow, then
back down to near 70 Friday night.
Fowler
LONG TERM [Saturday through Thursday]...
Environmental conditions will remain favorable for an active
weather pattern this weekend through the upcoming week. Confidence
in the potential for flooding across portions of SE Texas during
the extended period has increased as models get a bit more in sync
with a synoptic pattern that reflects favorable conditions for
periods of heavy rainfall.
An upper level low over Western and Central TX is progged to move
slowly eastward Saturday, continuing favorable jet dynamics for
storm development across Southeast TX. In addition, a few smaller
disturbances are expected to round the base of the associated trough
and move over the local area from time to time, further enhancing
the potential for storm activity. With persistent southerly flow
continuing to provide good surface moisture transport over the
local area (PWs of 1.8 to 2.0 inches), periods of locally heavy
rainfall are likely on Saturday. The upper low is expected to
reach Eastern/Northeastern TX by Sunday and meanders over this
area through Monday. Although the global models weaken the
low/trough over the Southern Plains, pulses of abundant surface
moisture will continue to move through the area, enough to
maintain periods of showers and thunderstorms both Sunday and
Monday. Beyond that timeframe, southerly flow will remain over the
local area, maintaining PWs of 1.7 to 2.0 inches through the end
of the forecast period. Unfortunately, models are now keeping the
upper level ridge more to the west midweek, thus, extending the
potential for active weather through the end of the forecast
period.
Total rainfall amounts of 4 to 7 inches can be expected during
the next 7 days, locally higher amounts are possible with very
slow moving storms or training. Considering the spectrum of
expected rainfall amounts, along with the fact that we will have
saturated soils lurking across portions of the CWA and water
levels running high in a few of our rivers, Southeast TX could
experience some flooding issues during the next few days. Flash
Flood Watches may begin to be issued in the next day or so.
Please stay alert and prepared in case one is issued for your
area.
High temperatures this weekend will be in the low to mid 80s and
in the mid to upper 80s next week. Low temperatures will
generally be in the upper 60s to low 70s inland through early next
week, and in the low to mid 70s through the end of the period.
-- Given it`s the long term period, changes to the forecast could
occur, although at this time, most models are in fairly good
agreement with the long term synoptic pattern.
24
MARINE...
Light winds will continue through the end of the work week across
the bays and waters along with seas of 1-3 feet. Winds increase
this upcoming weekend, possibly requiring Caution flags with seas
building up to 6 feet as a long fetch from the southern Gulf
develops. Chance of showers and thunderstorms can be expected
each day, with the heaviest activity expected to occur Friday
through Monday. Tides levels may also increase Sunday into early
next week.
For those planning to visit the beaches this weekend, strong rip
currents could occur across the Gulf facing beaches. Make sure to
monitor the local beach advisories.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 69 79 68 82 69 / 50 80 50 80 50
Houston (IAH) 70 80 70 82 71 / 60 80 60 80 60
Galveston (GLS) 75 81 75 82 76 / 70 70 60 70 60
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...99
Aviation/Marine...99
Area Forecast Discussion
National Weather Service New Orleans LA
929 PM CDT Thu Jun 3 2021
.EVENING UPDATE...
No significant forecast updates planned at this time in the short
term.
00z LIX sounding was rather moist and unstable with a precipitable
water value of 2.00 inches, which is in about the top 5%
climatologically for early June here.
We continue to be in southwest upper flow, and back to the
southwest, the soundings at Brownsville and Corpus Christi also
have precipitable water values around 2 inches, so don`t really
anticipate much change in available moisture. We continue to see
isolated to widely scattered convection fire along the
Mississippi and Louisiana coasts, even after sunset as weak
impulses move through the southwest flow. While the HRRR
solutions through 00z are drier tonight than they have been the
last couple of nights, not really comfortable with that trend
based on the soundings and radar. Will hold onto current depiction
of precipitation trends, mainly near the coast. A few spots will
see locally heavy rain which may require issuance of Flood
Advisories/Warnings, but large portions of the area could be dry
overnight. 35
&&
.PREV DISCUSSION... /issued 400 PM CDT Thu Jun 3 2021/
SHORT TERM (Tonight through Sunday)... Active pattern will
persist through the period. Long wave upper trough extends from
north of the Great Lakes into the Middle Mississippi Valley and
back into Texas. This trough will gradually lift northeastward
Friday, leaving behind a lingering upper low over Texas. Even with
the trough lifting out of the area, expect to see scattered to
numerous showers and thunderstorms on Friday.
Going into Saturday, expect to see a more noticeable gradient in
rain chances and coverage. As the upper trough moves farther
northeast and over the Atlantic, we`ll lose the influence of that
feature. However, there will still be a closed upper low centered
over Texas and the influence of that feature should still allow
for scattered to numerous showers and storms, with the highest
rain chances (around 60 percent) across areas nearest the
Atchafalaya River and lowest chances (around 30 percent) across
Jackson County on the MS Coast.
By Saturday night the low will begin to move northeastward, and a
fairly impressive slug of moisture will start to transit the
area from Southwest to northeast, leading to high rain chances
and potential for heavy rain, especially from the second half of
Saturday night through Sunday. Area average rainfall is currently
forecast in the 1-2 inch range, but there is potential to see
substantially higher amounts on the local scale - especially if
any given area sees multiple rounds of storms. As details become
clearer, may be able to narrow down areas of greatest risk and
increase the rain totals in those areas, but for now, most of the
area appears as though it could be under the gun.
Will also mention that strengthening onshore winds will lead to
higher tides Sunday and possibly into the first part of next week.
Current probabilistic guidance indicates high tides could reach
near or just over 1 ft MHHW at the Bay Waveland and Shell Beach
gauges Sunday and Monday, so may end up needing to issue a
coastal flood advisory for areas near the Rigolets through Bay St.
Louis. Will need to monitor conditions and trends over the next
couple days. Any impacts should be substantially less than what
was experienced last month. For comparison, winds over the water
are generally forecast in the 10-15 knot range for this period
while the event last month saw several days of winds in the
20-30 knot range.
LONG TERM (Sunday Night through Wednesday Night)...
As we move into Sunday night, the upper low will open up and the
deepest moisture will begin to pull away from the area. However,
weather remains unsettled with the now upper trough very slowly
drifting eastward across the Gulf Coast region. This will keep the
active and unsettled weather pattern in place with daily showers
and storms. Highest rain chances will generally be during the
afternoon hours with the aid of daytime heating.
AVIATION...
VFR conditions will prevail through most of the period outside of
showers and thunderstorms. Also some potential for patchy fog and
low ceilings near daybreak in areas where ground moisture is
higher from recent rainfall.
MARINE...
Bermuda high pressure off the southeastern US coast will continue
to keep an onshore flow through the forecast period. A moderate
gradient pattern will allow for winds to increase to the 10 to 15
knots going into the weekend. Seas will gradually respond,
building to 3 to 4 feet as well. Scattered showers and
thunderstorms each day will lead to locally higher winds and seas,
with a few of the stronger storms possibly resulting in wind
gusts in excess of 30 kts.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 68 83 68 83 / 30 60 20 50
BTR 70 84 69 83 / 30 70 20 50
ASD 70 85 69 85 / 40 60 10 40
MSY 73 85 74 84 / 50 60 10 50
GPT 71 84 72 85 / 40 50 10 40
PQL 70 85 69 85 / 30 40 10 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
732 PM EDT Thu Jun 3 2021
.SHORT TERM...(This evening through Friday)
Issued at 414 PM EDT THU JUN 3 2021
WV imagery and RAP analysis indicated a mid/upper level ridge from
the southwest CONUS to Saskatchewan and a trough into the central
Great Lakes resulting in northwest flow toward Upper Michigan. A
shortwave trough into western Upper Michigan supported an area of
light rain showers through portions of central Upper Michigan into
northern Wisconsin. Cloud cover with the shrtwv has been thick
enough to reduce insolation and instability to support tsra. Some
showers have developed along Lake breeze boundaries but have been
relatively weak.
Rest of today and tonight, expect there still may be enough heating
with thin spots in the clouds for MLCAPE values to around 500
J/Kg and some isold tsra to develop. Otherwise, as the remaining
showers will slide to the southeast as the shrtwv moves out of the
area. Lingering low level moisture along with clearing and temps
dropping into the low to mid 50s will result in potential for
patchy fog development.
Friday, as the mid level ridge builds into the region with
increasing southwest low level WAA (850 temp to around 18C) temps
will climb into the mid and upper 80s. Capping will be strong enough
to preclude convection. SSW winds at or below 10 mph will be weak
enough to lake breeze development off of Lake Superior with some
cooler air near the shore.
.LONG TERM...(Friday night through Thursday)
Issued at 350 PM EDT THU JUN 3 2021
A fairly broad ridge over the plain states, will continue to move
toward the upper Great Lakes region during the weekend. The ridge
axis will reach upper Michigan by early Sunday. Upper trough will
deepen over the western U.S. This trough has a tough time moving
into the upper great lakes. An associated cold front approaches the
area early next weak then stalls out. The precise location where it
stalls is still in question, but nevertheless, the best chance for
convection during the extended time frame will be Monday and
Tuesday. It currently looks like any ridge topping severe storms
will miss Upper Michigan, but that can change.
For Wednesday, the ridge builds back in and the surface front starts
moving north as a warm front. The chance of showers still exists
with this scenario, but deep convection looks capped off.
With the ridge dominating our weather pattern, expect above to much
above temperatures at least through the middle of next week. The
hottest days will be Saturday and Sunday with many locations going
over 90.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 724 PM EDT THU JUN 3 2021
Main concern for aviation interests for this TAF period will be
the potential for fog developing during the overnight hours at all
three terminals. Atmospheric moisture continuing to advect into
the area and low dewpoint depressions, along with relaxing winds
and a good chunk of clouds moving out of Upper Michigan will set
the stage for fog potential. Therefore, have continued to mention
this within the TAFs but will need to keep an eye once the fog
becomes evident to determine just how low visbys will go.
Currently, it appears KSAW has the highest chance of seeing the
lowest visbys (below 1 SM), followed by KIWD and KCMX. Aviation
interests should stay locked in with the latest obs and potential
updates/amendments as necessary. Once the fog dissipates tomorrow
morning, VFR conditions will dominate through the end of the
period, with generally light winds continuing. Could see a CU
field develop in the KSAW area tomorrow afternoon, courtesy of the
lake breeze.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 414 PM EDT THU JUN 3 2021
Expect winds across Lake Superior to be mostly under 20kt through F
Fri. Stronger winds are then possible on Fri night as low pres moves
e across northern Ontario. Wind gusts of 20-25kt will be possible
Friday night into Sat morning. Another period of stronger winds is
possible Sat night into Sun as another low pres moves e to southern
Hudson Bay. Although the air mass will be very warm, resulting in
very stable conditions over the waters, sw to s winds could
occasionally gust to 25kt to perhaps as high as 30kt at high obs
platforms at some point Sat night and Sun.
Fog may become an issue in the coming days as air mass over the area
becomes increasingly humid. However, with only minimal rainfall
confidence for widespread fog is low.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...KFM
AVIATION...lg
MARINE...JLB
AREA FORECAST DISCUSSION
National Weather Service Morristown TN
1011 PM EDT Thu Jun 3 2021
.UPDATE...
EVENING UPDATE.
&&
.DISCUSSION...
Radar shows the convection over the Plateau has generally been
weakening. A strong storm still cannot be ruled out, but overall
the threat of strong to severe storms has diminished. Will remove
severe mention from the HWO but will keep the mention of locally
heavy rainfall and possible localized flooding. Will drop thunder
to no more than slight chance, and will tweak PoPs/Wx to better
fit latest CAMS and radar trends. Will also make tweaks to
temps/dew points with this update.
&&
.AVIATION...
00Z TAF DISCUSSION.
There will be showers and a few thunderstorms around early in the
period. Will include VCTS all sites with a tempo group for the
period when showers look most likely. Once the showers move out,
at least partial clearing and light winds will provide the
opportunity for significant fog development. Still some
uncertainty in the details of any fog, but for now will take all
sites to IFR prevailing with tempo LIFR vsby/cigs. Will see
improvement to VFR all sites after sunrise. Winds will generally
be light.
&&
.PREV DISCUSSION...
/ISSUED 318 PM EDT Thu Jun 3 2021/
SHORT TERM...(Tonight and Tomorrow)...
Key Messages
1) Scattered showers and storms continue this afternoon into
the evening hours.
2) An isolated severe thunderstorm is still possible through early
evening, wind damage is the main concern.
3) Fog is possible overnight areawide.
Discussion...
Scattered showers and a few storms continue across the area this
afternoon. Most of the area remains fairly cloudy but some partial
clearing has been seen over the Cumberland Plateau over the past few
hours. There has been better clearing across middle TN and northern
AL and this is where new storms are currently developing. The latest
HRRR shows an uptick in shower and storm activity across our area
beginning around 20/21z. Then, scattered showers and storms
continue until around midnight as the cold front approaches and
moves through the area.
The greatest chance for any strong-to-severe storms looks to be
across the Cumberland Plateau, southern TN valley, and southwest NC
as these areas currently have the most instability. Northeast TN and
southwest VA are the most stable so they have a lesser chance of
seeing any stronger storms. Models do show instability increasing
northeastward into the central TN valley over the next several hours
so the central TN valley could also see some strong storms as well.
Wind damage is the main concern but we have noted some weak and
broad rotation with some of the cells down along the TN/GA line.
This is due to the weakly sheared environment that is in place with
roughly 15 to 20kts at 0-1km and 20 to 30kts at 0-3km. So we will
continue to monitor storms closely for any quick spin-ups. Lastly, a
few isolated areas across the southern TN Valley has seen 2 to 3
inches of rain so if these areas see anymore heavy rainfall flooding
could become a concern.
The HRRR shows showers exiting the area generally after midnight as
the front pass through the area. Guidance is hitting the fog pretty
hard tonight so have fog in areawide in the grids. Overnight lows
will dip down into the upper 50s to low 60s.
Tomorrow, the upper trough is lifting northeast out of our area but
a few scattered showers and a possible storm are possible before it
completely exits. This will mainly affect northeast TN and southwest
VA. Drier air moves in later in the day behind the front with
clearing skies. Highs will be in the upper 70s to low 80s.
SR
LONG TERM...(Friday night through Thursday)...
Key Messages
1) Warming trend and drier weather this weekend.
2) Increasing moisture, clouds, and rain chances next week.
Discussion...
Friday night into Saturday, an upper low will remain situated over
Texas while upper heights build over the southern Appalachians in
response to the departing upper trough and better alignment with
weak northern stream ridging. Expect a warming trend for Saturday
and Sunday in response to this low/mid level southerly flow regime.
Warmest temps on Saturday will be in the southern valley, but as H85
flow turns SSELY on Sunday expect the warmer temps to shift to the
northern half of the valley.
The TX upper low opens up late Sun but the resulting upper
trough/remnant upper low remains over that same general area into
early next week before meandering eastward through the end of the
period. The significance of this is that this continued southerly
low/mid level flow regime will bring increasing moisture and rain
chances to the forecast area beginning Sunday evening, but
especially ramping up Monday onward. This pattern will favor
diurnally driven convection, with showers and thunderstorms forming
in the mountains and plateau areas by early afternoon and pushing
into the valley during the evening. However, suspect there will be
some sporadic nocturnal convection as well due to weak but
persistent isentropic ascent Sunday night onward. Timing that will
be difficult so will favor diurnally driven PoPs for the time being.
After the warmup on Sat and Sun, the increased cloud cover and rain
chances next week should bring highs back down to around normal
values.
CD
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 64 85 63 89 67 / 50 10 0 10 10
Knoxville McGhee Tyson Airport, TN 64 82 62 87 64 / 50 10 10 10 10
Oak Ridge, TN 61 83 61 87 63 / 70 10 10 10 10
Tri Cities Airport, TN 61 79 57 85 60 / 50 20 10 10 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
Area Forecast Discussion
National Weather Service Nashville TN
808 PM CDT Thu Jun 3 2021
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Surface boundary continues to progress slowly eastward across the
Cumberland Plateau, with only a few remaining cells still showing
up on radar. Expect these to exit the region in the next couple of
hours. HRRR shows no redevelopment afterwards. Look for patchy
fog overnight as radiational cooling takes over. Fog could be
dense in a few spots owing to the wet ground and lingering high
dew points. Current grids seem to have a good handle on the
overnight forecast, so no changes are planned at this time.
&&
.AVIATION...
00Z TAF DISCUSSION.
BNA/MQY/CKV/CSV...A cold front has just about made it all the way
across Middle Tennessee. The only remaining convection is
occurring along and just west of the Cumberland Plateau in the
vicinity of the surface boundary. Look for this activity to exit
the region by early evening as the front continues eastward.
Tonight looks to be a good night for radiational cooling, and with
a wet ground and high dew points, we are expecting areas of fog.
So we`ll include mention of fog in the TAF`s. Tomorrow, expect
VFR wx and light winds.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......08
AVIATION........08