Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/20/23
Area Forecast Discussion
National Weather Service Jackson MS
911 PM CDT Mon Jun 19 2023
...New MESOSCALE UPDATE...
.MESOSCALE UPDATE...
Issued at 853 PM CDT Mon Jun 19 2023
The bulk of the thunderstorm activity has moved to the south of
the area this evening, but showers/storms will continue to be
possible mainly in the south and southwest through the night. The
HRRR develops another round of storms over the southwest later
tonight into early Tuesday, and some of the storms could be strong
to possibly severe with heavy rainfall. Will continue to
advertise this potential in the HWO/Graphicasts. Lows tonight will
range from the mid 60s in the east to the mid 70s in the
west./15/.
&&
.DISCUSSION...
Issued at 459 PM CDT Mon Jun 19 2023
Tonight through Tuesday: The weather pattern responsible for the
recent barrage of severe weather and flooding will begin to
transition to a more seasonable weather pattern this week.
Greater influence from an upper low over the Southeast CONUS will
help to bring drier air into our area while forcing the frontal
boundary southward to near the coast. With greater moisture
convergence anchored over southwest/southern portions of the
forecast area, much of the area will dry out and can expect
decreasing heat/humidity as well. At the same time, deep layer
flow will relax some as well, but there will still be enough to
support storm organization over northeast LA into southern MS
should storms manage to form. With this in mind, will continue to
message for low level severe weather threats, and have also
included a limited threat for heavy rainfall/flash flooding in
the same area. Some guidance suggest that any storms could tend to
backbuild and train across southwest portions of the area. Will
monitor for this conditional threat, but overall the forecast is
much quieter than it has been recently. /EC/
Tuesday night through early next week: The main focus in the long
term will be an upper low pressure system centered over Alabama,
which will turn our flow northerly and advect anomalously drier
air through the column (PWAT <1.3 inches) and a slightly cooler
boundary layer airmass (Highs upper 80s to lower 90s) which will
tend to limit rain chances, especially across the northern half of
the area. A rex block over New England will likely keep this
regime for the remainder of the week.
Far southern areas (generally south of the HWY 84 corridor) will
likely be less influenced by this regime and will remain in
seasonable moisture that will be sufficient to support continued
rain and storm activity. A boundary in the vicinity of this region
will likely further aid in this activity.
Attention turns to a building upper ridge over Texas for late week
and into early next week likely increasing moisture and
temperatures. Current global model outputs suggest PWAT in excess of
2 inches with temperatures in the mid to upper 90s. Could have to
monitor for microburst potential as well as heat potential should
these conditions continue to trend in models for early next
week./SAS/
&&
.AVIATION...
(00Z TAFS)
Issued at 648 PM CDT Mon Jun 19 2023
VFR conditions will prevail at TAF sites through the period.
Breezy westerly winds will become light and variable
overnight./15/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 91 69 92 69 / 20 0 10 10
Meridian 90 68 92 68 / 30 0 10 10
Vicksburg 91 71 92 70 / 10 10 10 10
Hattiesburg 93 70 93 70 / 50 30 30 30
Natchez 94 73 90 69 / 30 20 50 30
Greenville 89 70 91 70 / 0 0 0 0
Greenwood 89 69 91 69 / 0 0 0 0
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
15/
Area Forecast Discussion
National Weather Service Louisville KY
801 PM EDT Mon Jun 19 2023
.Forecast Update...
Issued at 801 PM EDT Sun Jun 18 2023
Stacked low pressure is spinning over south-central KY this evening,
with bands of showers wrapping cyclonically around the low. The
atmosphere is very moist with SDF ACARS soundings and RAP
mesoanalysis data featuring PWATs around 1.7 inches. Mixed-layer
CAPE is decreasing thanks to rain-cooled air and approaching sunset.
Thunderstorms are now quite isolated, though visible satellite data
shows lingering convection near the low in south-central KY.
LightningCast probabilities are still elevated (50+% 60-min
lightning probability) in that region.
Instability will continue to weaken over the next few hours, and
coverage of showers will also begin to decrease in that time. Only
isolated to widely scattered showers are expected late tonight into
early Tuesday.
Stronger instability was present earlier this afternoon with MLCAPE
peaking near 1000 J/kg. CAPE and abundant moisture contributed to
very high rainfall rates in convection, which led to localized
excessive rainfall. Relatively slow-moving convective bands near the
pivot point produced 1-3 inches of rain, with 1-2 inches of that
falling in less than an hour over portions of Marion, Hardin,
Bullitt, and Jefferson counties. For example, 3.01 inches of rain
has fallen at the NWS Louisville office in South Louisville just
since 2 PM EDT. Very heavy rainfall rates did lead to localized
flooding, including some street flooding.
&&
.Short Term...(This evening through Tuesday)
Issued at 310 PM EDT Mon Jun 19 2023
Currently... The surface low pressure system is circulating over our
southern counties. This is leading to scattered-widespread showers
north of I-64 and scattered showers and storms south of I-64. Most
of the region has already seen about an inch of rainfall, however in
some localized areas we have seen around 2.0-2.5 inches of rain
during heavy downpours.
Tonight... Showers and scattered storms will continue into the
night, however they will begin to thin out. With high dew points, a
low cloud deck will likely develop tonight. This cloud deck will
prevent overnight cooling, so low temperatures Tuesday morning are
expected to be in the upper 60s and low 70s. Tonight will likely
feel muggy and misty.
Tomorrow... Scattered showers and storms are possible over the
region tomorrow morning and will increase in coverage in the
afternoon. Forecast soundings are similar to today with PWATs around
1.75-1.9 inches, and modest instability (1000-1500 J/kg MLCAPE).
Severe threat is low again tomorrow with the only concern being
heavy downpours with stronger storms. We could see another inch of
rain fall tomorrow over most of the area, and with stronger storms
we could see locally higher totals. Showers and storms will taper
off into the evening. With continued showers and storms, high
temperatures are likely to stay in the upper 70s and low 80s.
Overall... Showers and storms continue in the short term period
bringing much needed moisture into the region. Forecast confidence
is medium-high.
.Long Term...(Tuesday night through Monday)
Issued at 345 PM EDT Mon Jun 19 2023
The stacked low bringing our current rain showers is expected to be
to our south over the northern parts of the Alabama/Georgia border.
This is expected to give us a break from rainfall Tuesday night, but
as we head into Wednesday, expect an uptick in precipitation, mainly
during the afternoon and evening hours. Bands of showers are
expected to work from east to west around the circulation, so some
areas could see prolonged rainfall. Instability will be marginal,
and shear remains weak. This will lead to a mostly rain event with
no severe weather expected. Flooding isn`t expected, but will
continue to be monitored.
Wednesday night, the upper high just north of the Great Lakes will
begin to get pushed to the east. This will allow the aforementioned
low pressure system to work north towards the CWA. Expect enhanced
precipitation chances through Friday as more rounds of showers
traverse the Lower Ohio Valley. Instability and shear will remain
weak.
Friday night into Saturday, upper flow will finally start pushing
the decaying low pressure system eastward. This will begin to reduce
precipitation chances and increase sunshine for the weekend, but
high dew points and diurnally induced instability will increase the
likelihood of afternoon and evening convection.
Through the end of the work week, temperatures will remain fairly
mild with all the cloud cover keeping highs in the mid to upper 70s
during the day and only dropping into the low to mid 60s at night.
The weekend will see a return of mid and upper 80s.
&&
.Aviation...(00Z TAF Issuance)
Issued at 729 PM EDT Mon Jun 19 2023
Stacked low pressure is spinning over south-central KY this evening,
with scattered to numerous SHRA ongoing. Showers will diminish
somewhat in coverage and intensity after 03z Tue. Overall, drier
conditions are anticipated Tuesday morning. However, mist or
isolated light rain could occasionally limit visibility overnight.
Though, the main aviation concern will be IFR/low MVFR ceilings.
Low clouds and isolated SHRA will be the theme through Tuesday
morning, with SCT-NUM TSRA blossoming starting around 18z across
central and southern KY. Northeasterly winds of 5-10 kts will be
common through the period.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...EBW
Short Term...SRM
Long Term...KDW
Aviation...EBW
Area Forecast Discussion
National Weather Service Melbourne FL
1010 PM EDT Mon Jun 19 2023
...SEVERE STORMS CONTINUE OVER THE SPACE COAST, EXITING
OVERNIGHT...
...New MESOSCALE UPDATE, MARINE, AVIATION...
.MESOSCALE UPDATE...
Issued at 1008 PM EDT Mon Jun 19 2023
Severe storms continue to affect the Space Coast this evening. Wind
gusts from 40-60 MPH are occurring, locally upwards of 70 MPH. A 68
MPH gust was observed on the northern end of Canaveral Natl Seashore
just a bit ago. Secondary threats of hail to quarter size and a
brief tornado spin-up exist as well, but straight-line winds are the
main concern.
These storms lined up on an eastward moving vort max, analyzed
nicely on the RAP this evening. This energy is on the southern flank
of an upper low sitting across the southern Appalachians. Strong
theta-E advection occurred on the advancing Atlantic breeze, with
convergence maximized where the thunderstorm outflows and sea breeze
collided.
This activity will push offshore by midnight with improving
conditions for the overnight. Would expect some subsidence behind
these storms to carry us toward daybreak at least. However, yet
more energy is evident with storms continuing over the AL/MS
panhandles at this hour. Confidence continues to be lower than
normal in timing of showers/storms into Tuesday. Once this round
gets out of here, we should be able to get a better idea of how
Tuesday will evolve. However, we do expect more storms tomorrow.
Lows will drop into the low 70s overnight.
&&
.MARINE...
Issued at 1008 PM EDT Mon Jun 19 2023
Strong to severe storms will affect the near and offshore waters
through midnight with abruptly gusty/strong winds and locally higher
seas. This activity will calm some overnight with only isolated
storms remaining. Prevailing winds become SW overnight through
tomorrow, generally 10-15 KT. Seas 1-2 feet, locally 3 feet
beyond 20 nm.
&&
.AVIATION...
(00Z TAFS)
Issued at 1008 PM EDT Mon Jun 19 2023
Challenging TAFs this evening as storms affect the terminals and
timing for next round of storms tomorrow is still uncertain. For
coastal terminals, storms end after 3-4Z with quieter conditions
overnight. Another round of showers and storms could begin as early
as tomorrow morning after 12Z, however this is a low confidence
forecast. Prevailing winds will return to S/SW after the storms
exit this evening, 5-10 KT overnight increasing to 10-20 KT
Tuesday (somewhat gusty).
&&
.PREV DISCUSSION...
Issued at 229 PM EDT Mon Jun 19 2023
Tuesday-Wednesday...Cut-off mid/upper level low will continue to
linger across the southeast U.S. through mid-week, maintaining an
unsettled weather pattern across the area. At the surface a
stalled frontal boundary near to north of Florida will keep the
subtropical ridge axis south of the region, with a prevailing and
elevated W/SW flow across central FL. Plenty of moisture remains
in place, with PW values around 1.8-1.9 inches to maintain the
development of numerous shower and storms through midweek.
Convection may start of earlier than normal, with passing
disturbances generating storms over the eastern Gulf and western
side of that state that are steered eastward into the area during
the morning. Then should see additional rounds of showers and
storms into the afternoon/evening hours, especially should there
be sufficient daytime heating. Rain chances remain high up to
75-90+ percent each day, with strong to marginally severe storms
continuing to be possible. Main storm threats will be strong winds
to 40-60 mph, small hail, frequent lightning strikes and locally
heavy rainfall daily up to 2-3 inches.
The potential for an earlier start to showers and storms and
increased cloud cover will keep max temps a little lower, in the
upper 80s to low 90s. Overnight conditions will remain humid, with
lows in the low to mid 70s.
Thursday-Sunday...Low aloft will finally begin to shift northward
and weaken through late week, decaying to a trough that will shift
offshore the eastern seaboard into the late weekend/early next week
time frame. Both the GFS and ECMWF then drag deeper tropical
moisture northward across the area through late week and into this
weekend, with the GFS a little faster with this moisture surge. PW
values remain 2+, which will not only maintain high rain chances
across the area (around 70-80 percent), but will also increase
the threat of localized heavy rainfall and flooding through this
period. Some stronger storms will continue to be possible,
especially into Thursday, when S/SW winds remain elevated across
the region. Higher rain chances and increased cloud cover will
keep max temps near to slightly below normal in the upper 80s to
low 90s, and overnight lows will continue to range from the low to
mid 70s.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 75 88 72 88 / 60 80 60 90
MCO 76 89 74 88 / 60 80 60 90
MLB 75 91 74 90 / 60 80 50 80
VRB 75 91 72 91 / 60 70 40 70
LEE 74 86 73 87 / 60 80 70 90
SFB 75 88 74 89 / 60 80 60 90
ORL 76 89 74 89 / 60 80 60 90
FPR 75 91 74 90 / 60 60 40 70
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
FORECASTS/AVIATION...Heil
RADAR...Cristaldi/Tollefsen
Area Forecast Discussion
National Weather Service Marquette MI
1153 PM EDT Mon Jun 19 2023
.SHORT TERM...(This evening through Tonight)
Issued at 343 PM EDT MON JUN 19 2023
The weak shortwave/vort max that is slowly drifting across WI and
the western UP continues to produce a few spotty showers this
afternoon. Cloud cover associated with this feature stymied max
temps by 1-3F so far today and have also prevented dew points from
mixing out quite as much with most sites in the 50s except for a few
upper 40s across the east. This has resulted in RH values dipping to
around 30% in the driest eastern locations with values around or
above 40% more common across the west/central UP. This somewhat more
humid air mass combined with light winds has limited fire wx
concerns, but burn restrictions remain in effect due to unusually
dry fuel moisture levels.
Visible satellite shows an increasingly agitated cumulus field
across western WI, especially along the lake breeze boundary pushing
into northwestern WI. The latest RAP analysis shows less then 500
J/kg MUCAPE and soundings show an inversion around 15kft that should
prevent updrafts from deepening. Despite this generally unfavorable
environment, this mornings 12z HREF shows shower chances up to
around 30% for Gogebic and Ontonagon Counties this afternoon, but
better chances are across WI. Based on that, mentionable PoPs end
quickly this evening across the west. Elsewhere, somewhat lighter
southerly winds than yesterday allowed a lake breeze to push farther
inland today. It reached our office around 230 PM and temps dropped
from 82F to 77F with it`s passage. With dry surface ridging building
from ~1016 mb to ~1020 mb overnight, not expecting much weather to
contend with. Lingering clouds should clear out as temperatures cool
mainly into the 50s tonight. Some cooler eastern sites possibly
dipping into the upper 40s and some warmest western sites possibly
staying in the low 60s.
.LONG TERM...(Tuesday night through Monday)
Issued at 321 PM EDT MON JUN 19 2023
Mid-upper level ridging over the Upper Great Lakes will become
increasingly amplified by midweek as a rex block takes shape over
the east half of the CONUS. Anomalously strong ridging by midweek
with this pattern will result in continued dry weather and a trend
toward very warm to hot conditions for the mid to late week period.
Any relief from the hot and dry weather may not come until late
weekend into early next week when the mid-level ridge finally gets
pushed east and is replaced by a trough/closed low moving over the
Upper Great Lakes.
An anomalously strong ridge will dominate the region Tuesday through
Thursday, continuing the dry spell with warm to hot conditions. With
forecast 850mb temps in the 15 to 18C range and 5H heights exceeding
590 dam under mostly clear skies, this should yield inland max temps
well into the most days with lower 90s probable over the interior
west. The hottest days will likely be Wednesday and Thursday. These
interior locations can expect mild overnight conditions with min
temps in the mid 50s to lower 60s. By the lakeshores, the wind
direction will factor heavily into daytime heating. Prevailing
southerly flow off Lake Michigan could keep eastern counties from
getting too hot, especially for locations along the shore where
readings should be in the upper 70s to lower 80s. Forecast temps
could be trickier along the Lake Superior shore as the prevailing
southerly flow some days may be strong enough to suppress lake
breezes and a downsloping flow could end up keeping temps warmer
instead of cooler, although most days should be around 80F. Diurnal
mixing should support min RH values falling into the 30-40% range or
lower each afternoon continuing elevated fire weather concerns each
day. Fortunately, winds should not be overly strong under the ridge,
and there should be a good potential for lake breezes each day.
Although the rex block generally breaks down late week over the
eastern CONUS, deterministic models and ensembles are trending
toward ridging possibly holding on a few more days over the Upper
Great Lakes, continuing the mostly dry and very warm weather Friday
into Saturday.
By late weekend into early next week, deterministic models and
ensemble means suggest mid-level ridging will finally move east and
be replaced by a trough/closed low from the west. The closed low
will increase chances for showers/t-storms Sunday into Monday while
providing some relief from the heat.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1151 PM EDT MON JUN 19 2023
VFR conditions to continue for the duration of TAF period with
dry environment still in place. Meanwhile, winds will be south-
southeasterly at IWD and SAW and more east-southeasterly at CMX.
Wind speeds generally less than 10 kts except for a brief uptick
to 11 kts at SAW later this afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 321 PM EDT MON JUN 19 2023
Continued light winds are expected across Lake Superior thanks to
persistent ridging over the region. This should yield winds of 20kts
or less, with higher reporting platforms potentially sampling above
the marine layer and observing some higher winds here and there.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...EK
LONG TERM...Voss
AVIATION...TDUD
MARINE...Voss