Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/18/24
Area Forecast Discussion
National Weather Service Gaylord MI
1145 PM EDT Fri May 17 2024
.KEY MESSAGES...
- Warm Saturday.
- Weakening cold front arrives Saturday night...dwindling rain threat
along it.
- Sunday afternoon lake breeze convection near Lake Huron? (Definitely
a non-zero probability)
- Weather more unsettled starting Monday...strong storms maybe Tuesday
night?
&&
.UPDATE...
Issued at 1051 PM EDT Fri May 17 2024
Weak high pressure over much of the Great Lakes continues to
produce clear skies across Northern Michigan late this
evening. Spotty diurnally-induced clouds and convection have
dissipated...leaving mostly clear skies across our entire CWA
attm. Still expect some low status/fog development overnight
across portions of Eastern Upper...far Northern and NE Lower
Michigan thanks to E/SE low level flow off of the cool waters
of Lake Huron. Rest of our CWA should stay mostly clear
overnight. Low temps will drop into the upper 40s to lower 50s.
&&
.SHORT TERM /THROUGH SATURDAY/...
Issued at 351 PM EDT Fri May 17 2024
Pattern/Synopsis: Decaying surface front has progressed into ne
lower MI. After that washes out, broader and warm southerly flow
gets established tonight and especially Saturday, well ahead of low
pressure in s central Canada.
Forecast: With stronger surface heating finally being realized,
convection has sprouted in ne lower MI, where moisture is pooled
near the decaying front. SPC mesoanalysis has a skinny axis of circa
1k j/kg of MlCape extending into ne lower MI. First couple cells of
the day had no problem getting strong, with one become marginally
severe. Now outflow air covers a good portion of this area, though
there is time for recharging. Additional cells should also cook off
along the westward-moving outflow boundary, though instability is
weaker with westward extent (BL moisture is less...59f dew point at
APN now, vs 50 at GLR and 48 at TVC). Convection will continue to be
extremely averse to moving out over chilly Lk Huron.
Spotty convection should continue in ne and perhaps n central lower
MI, well into evening. Have stretched out those pops a little
longer. A n-s convergence line is also progged to form down the
spine of central lower MI over the next few hours, thanks to
continued heating. A number of HRRR runs generate convection here by
early evening, then propagate it east with some marginal upscale
growth. Another reason to stretch out pops a hair longer.
Otherwise, diurnal cu will diminish. Light surface winds will allow
for good radiational cooling. Low-level moisture will be less than
this morning (except potentially for where it rains). Do have plenty
of low clouds (and fog) returning to eastern upper and ne lower MI
by morning. Fog/stratus should be more localized in nw lower MI.
Min temps upper 40s to lower 50s.
Fog/stratus should be somewhat faster to erode Saturday. Ne lower MI
coastal counties, and eastern Chip/Mack Cos, could see clouds until
almost lunchtime. Otherwise, mostly sunny skies, and with warm
advection beginning, it`ll be toasty (away from the big lakes).
Highs were boosted into the lower 80s across much of northern lower
MI, with 70s along the coasts and in eastern upper MI.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 351 PM EDT Fri May 17 2024
Pattern Forecast: Several pieces of short wave energy lined up in
the northern branch wave train extending across the Pacific. First
feature of interest is over the Pacific Northwest this afternoon
that will swing across the upper Midwest and into northern Ontario
Saturday...with another wave on its heels Sunday but this trough
will dig/amplify over the western U.S. to start next week. Southwest
flow aloft will predominate across the Great Lakes...with a spell of
warmer and potentially more unsettled weather by midweek as a
result.
Lead short wave moving into Ontario will push a cold front into
Michigan Sunday though it will likely tend to wash out. After that
evolution of western trough and its impact on the surface pressure
pattern starting Monday as an intial lee cyclone that develops as it
tracks into the upper Midwest and (perhaps) the upper Lakes Tuesday
but there is spread in the ideas of system evolution which will
dictate timing of cooler air back into Michigan (roughly Wednesday
vs. Thursday).
Primary Forecast Concerns:
Weakening cold front arrives Saturday night...dwindling rain threat
along it: Expect a line of convection to develop along the front
over western Upper/Wisconsin Saturday afternoon/evening...with the
remnants moving toward northern Michigan Saturday night along a
narrow low level theta-e axis coincident with the front. Better
rain probabilities are indicated across eastern Upper but can`t
really rule out some rogue showers popping anywhere overnight into
Sunday morning (northeast Lower).
Sunday afternoon lake breeze convection near Lake Huron? (Definitely
a non-zero probability): Cold front looks to fall apart across
Lower Michigan Sunday but a weak gradient expected to allow for lake
breeze development with strongest convergence near Lake Huron.
Coincidentally looks like a west-east moisture gradient is going to
set up (boundary layer mean mixing ratios ranging from around 4g/kg
eastern Upper to 11g/kg near Saginaw Bay. As a result dew points
will likely remain in the 55-60F range roughly east of an HTL-APN
line. This should generate several hundred J/kg MLCAPE values...
enough to justify at least some PoPs over parts of northeast Lower
(same area mentioned above). NBM probabilities are hinting at this
but have blended in higher SREF PoPs to better get the idea in the
forecast.
Weather more unsettled starting Monday...stronger storms maybe
Tuesday night?: Surge of deep moisture into the Great Lakes ahead of
the digging upper trough (precipitable water values 1.25+ inch) will
begin to increase rain chances on Monday (evolution of this may
revolve around upstream convection which always complicates things).
But arrival of the surface low and attendant warm sector into the
upper Lakes on Tuesday certainly portends the potential for more
significant weather...especially on the other side of Lake Michigan
as usual but a nice nocturnal squall line passage could be in the
offing Tuesday night. At least the setup is good for it...the devil
is in the details of course. SPC Day 5 15% severe probability
knocking on western Lower`s door...along with the Day 5 marginal
risk the WPC Excessive Rainfall Outlook which is not unreasonable
given the potential magnitude of moisture advecting northward.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1145 PM EDT Fri May 17 2024
Weak high pressure centered over Eastern Upper and Lower Michigan
will slowly push eastward overnight into Saturday. Meanwhile...
an upstream cold front will slide into the Western Great Lakes
region Saturday afternoon and night. Dry wx is expected across
our area overnight thru Saturday evening...before chances of
showers and storms begin to increase late Saturday night. Areas
of low stratus/fog/IFR conditions will develop late tonight
into early Saturday across Eastern Upper and far Northern/NE
Lower Michigan. VFR conditions will return to this area later
Saturday morning and afternoon as daytime mixing helps to
lift/dissipate the low status and fog. Light/variable winds
overnight will become SE under 10 kts on Saturday...lending to
lake breeze development along our shoreline areas.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
UPDATE...MLR
SHORT TERM...JZ
LONG TERM...HAD
AVIATION...MLR
Area Forecast Discussion
National Weather Service Columbia SC
907 PM EDT Fri May 17 2024
.SYNOPSIS...
Chances of showers and thunderstorms will continue overnight as a
weak system begins to slowly cross the region. Rich moisture across
the region will keep rain chances likely lingering into Sunday.
Cooler and drier air moves in for Monday and Tuesday with
temperatures rebounding during the middle of next week as another
ridge moves in from the west.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
Positively tilted upper trough continues to slowly progress through
over the central/southern Plains toward the Mississippi River Valley
this evening. Southwest flow aloft continues to usher in moisture
with PWATs between 1.5" and 1.7" and dewpoints in the mid to upper
60s. PW values are expected to increase overnight to between 1.7"
and 1.9", with a few locations closer to 2" across the CSRA/southern
or eastern Midlands.
Ongoing convection to our south is progged to remain out of the area
tonight. However, weak short wave energy moving through the mid
level flow is expected to generate scattered showers across the area
amid increasing isentropic lift. The latest HRRR shows a reasonable
solution, with perhaps a bit of a stronger area of showers and
thunderstorms pushing through the CSRA around daybreak. Severe
threat remains low though brief heavy rainfall is possible.
Overcast skies and a well-mixed boundary layer keep overnight lows
quite mild, only falling into the mid to upper 60s/near 70. Low
dewpoint depressions may generate some reduced visibilities in and
near shower activity.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Positively tilted trough will continue to slowly push eastward
towards us and should be centered across the lower MS Valley by
tomorrow morning. Strong flow at 500 hPa is expected to create
strong shear profiles, and CAMs are generally showing some sort
of MCS structure to our southwest, but how far north this gets
and how fast it will be is in question. Generally, guidance has
struggled with speed and placement of convective structures like
this in recent weeks. So there is uncertainty about this, but
confidence is high that an MCS of some sort will be in central
GA at the start of this period. Ahead of this, rich moisture
should favor some instability, and given the shear in the
atmosphere, strong to marginally severe storms are again
possible depending on the location of this convection. Thinking
the best chance for this is in the southern FA, but timing and
severity is hard to piece together right now. Think it`ll be
approaching or through our FA by late morning, and if this
happens, it opens the door for some afternoon sunshine and
another round of thunderstorms in the central and northern FA.
While the strongest shear will be to our east, robust
instability is possible where we see sunshine tomorrow afternoon
so we`ll need to watch for strong strong storms along an
amorphous surface front across the northern part of SC. Highs
should generally be in the mid 80s but upper 80s are possible
for those that see more sunshine. Showers will probably hang
around into Saturday night as the trough approaches with lows in
the mid 60s expected. On Sunday, more showers and embedded
thunderstorms are possible as the trough approaches and pushes
over the region. Some uncertainty is present with where the
surface low and resultant convergence develops, adding some
overall uncertainty to rain coverage Sunday afternoon. But
confidence is high that we`ll see scattered to numerous showers
across much of the area, with highs in the upper 70s and low
80s. Showers should clear out on Sunday night as a back door
front pushes through and pushes low PW air into the area.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Confidence continues to remain fairly high in the long term
period. Cool and dry air is expected to remain in place on
Monday, with highs well below normal near 80s. Modification
quickly begins on Tuesday as high pressure shifts to our east
and ridging aloft begins to build. This should carry highs back
into the upper 80s and low 90s by Thursday. Another cold front
is forecast to approach by the Thur/Fri timeframe, with the
possibility of showers and thunderstorms in the afternoon in
association with that.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... Restrictions to
begin overnight and continue into Saturday.
A few showers earlier this evening have moved out of the region,
leaving behind VFR ceilings for the time being. After sunset,
ceilings are expected to lower to eventual IFR levels after
about 07z. Guidance is not as consistent at AGS/DNL for IFR, so
addressed that with a TEMPO group. Low level moisture will also
likely lead to areas of fog overnight with scattered showers
possible. Latest guidance has been indicating less shower
coverage overnight than earlier runs, but with the low level
moisture in place, showers can`t be ruled out. Ceilings begin to
improve after 15z or 16z, and anticipated to return to VFR after
around 21z.Another round of showers and potential thunderstorms
arrives late in the period.
EXTENDED AVIATION OUTLOOK...Increased confidence in
restrictions with showers and thunderstorms continues through
Sunday night.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service Cleveland OH
1020 PM EDT Fri May 17 2024
.SYNOPSIS...
Weak low pressure aloft will slowly push a cold front across the
region tonight and Saturday. The front will wash out over the
Appalachians late Saturday followed by high pressure building in
Saturday night. The high will remain in control through Tuesday
before low pressure and a cold front approach by Wednesday.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
10:19 PM EDT Update...
At time of writing, a broken line of showers/thunderstorms is
continuing to persist E`ward across portions of NW PA, NE OH,
and Mid-OH as the collective downshear outflow boundary
interacts favorably with ambient, albeit weak, low-level
vertical wind shear amidst sufficient boundary layer moisture
and instability. Expect this convection to dissipate and/or exit
our CWA by midnight tonight as mean mid-level flow remains
W`erly and the boundary layer continues to stabilize via
nocturnal cooling. A diffuse low-level convergence zone
associated with a weak surface trough axis persists near a
roughly Findlay to Mansfield to Meadville, PA line this late
evening. This weak surface trough axis is expected to drift
SE`ward and exit the rest of our CWA during the predawn hours of
Saturday morning. Given continued boundary layer stabilization
via nocturnal cooling through daybreak Saturday morning, the
potential for additional convection to blossom along this
trough axis is limited, but non-zero. A cluster of showers
and thunderstorms is persisting generally S`ward over
southeastern Lower MI, but expect this convection to dissipate
before reaching our CWA due to aforementioned nocturnal boundary
layer stabilization. However, will continue to watch this
convection closely. Behind the weak surface trough, a weak and
stabilizing surface ridge builds from the west and north through
Saturday night, which is expected to allow fair weather to
grace our entire CWA. Updated POP`s and sensible WX grids
accordingly.
The other concern through most of Saturday morning is fog.
Nocturnal cooling amidst lingering low-level moisture,
including that from recent rainfall, and a weak synoptic MSLP
gradient will continue to permit the development/downward
expansion of widespread stratus and radiation fog development
the rest of this evening and especially early Saturday morning.
Also expect limited nocturnal cooling/resulting reduction in
surface dew point depressions to allow at least patchy
advection fog to develop over Lake Erie overnight tonight,
especially east of roughly Avon Point, OH. Issued a Dense Fog
Advisory where forecast confidence is greatest in the
development of at least areas of dense fog by daybreak. The
advisory is in effect from 12 AM to 10 AM EDT Saturday. Any fog
should dissipate by late Saturday morning, once diurnal
convective mixing of the boundary layer commences and taps into
drier air aloft. However, some NWP models suggest at least
patchy advection fog over Lake Erie may linger well into
Saturday. The rest of the forecast remains valid. Please see
discussion below for further details.
Previous Discussion from 3:55 PM EDT...
A weak but broad mid/upper trough remains across the Great Lakes and
Ohio Valley this afternoon, with associated weak surface low
pressure just south of James Bay extending a cold front through
Lower Michigan and Indiana. Synoptic forcing and deep layer wind
profiles are very weak, but upper-level diffluence and the right
entrance region of a 75-85 knot H3 jet streak lifting through
the southern Great Lakes generated widespread shower activity
this morning since plenty of low-level moisture is in place. The
steadiest showers are currently exiting far eastern Ohio and
western PA coincident with the aforementioned jet streak lifting
out of the region, but breaks in the cloud cover are generating
weak to moderate instability characterized by SBCAPE of
1000-1500 J/Kg in NW and north central Ohio. This combined with
continued low-level moisture (dew points low/mid 60s) and upper
diffluence and low-level confluence ahead of the cold front is
supporting the development of diurnal convection. Doppler radar
and visible satellite loops show most of this developing from
north central Ohio through the central highlands at the time,
but development is also taking place in Lower Michigan away from
the lakes. With all of this in mind, all areas could see
passing showers or thundershowers this afternoon and evening,
but the greatest potential is over the southern and eastern
counties from roughly Mt. Vernon to Youngstown, so put the
highest PoPs there through the evening. Since the flow aloft is
weak, deep layer shear values will only be 10-15 knots, so
severe weather is not expected. The only concern with the
convection will be locally heavy rainfall that could lead to
localized, nuisance flooding. PWATs remain in the 1.3 to 1.5
inch range in much of the area which is around the 90th
percentile of daily climatology for the date, and RAP forecast
soundings show fairly tall, skinny CAPE with freezing levels a
little above 700 mb. This combined with the weak flow profile
and the flow parallel to the front will allow for some slow
moving convective cells with efficient rainfall rates of 1-2
inches per hour. Any issues would likely be if convection can
train.
The weak mid/upper trough axis will further weaken and move east of
the region tonight and Saturday allowing shortwave ridging and broad
surface high pressure to nudge in from the west by Saturday night,
but it looks to be a slow process since two northern and southern
stream weak troughs are pretty separated from the main jets aloft.
This will cause the weak cold front to slowly progress east and
southeast across the region tonight and Saturday before washing out
near the Appalachians. Most areas will dry out tonight, but with the
front and associated low-level moisture taking their time exiting on
Saturday, diurnally driven convection will develop again from late
morning through the afternoon, mainly east of I-77. Coverage should
however be less than today, but locally heavy downpours could occur.
All areas will dry out Saturday night as the high builds in.
Lows tonight will range from the upper 50s to around 60, with highs
Saturday in the upper 70s/low 80s in NW and north central Ohio where
more sunshine occurs, but mid 70s in NE Ohio and NW PA. Lows
Saturday night will fall into the mid/upper 50s.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The weather pattern will shift to a hotter and more summer like for
later this weekend into early next week. An upper level ridge of
high pressure will develop and expand over the Ohio Valley region
Sunday and Monday. The main storm track will shift northward into
the Upper Midwest and Upper Great Lakes region for a few days. With
high pressure in control, we will expect fair weather conditions
with mostly sunny to partly cloudy skies. High temperatures on
Sunday afternoon will range from the lower to middle 80s. There
could be a light lake breeze Sunday afternoon closer to the
lakeshore that may keep temperatures in the upper 70s. We will add
another degree or two for Monday afternoon with high temperatures
ranging from the lower to upper 80s. We should stay dry Sunday
through Monday.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
High pressure will continue to remain in control of our weather on
Tuesday keeping us very warm and dry. Temperatures will be once
again in the middle to upper 80s. By Tuesday night, the upper level
ridge of high pressure will begin to break down and a series of
shortwave troughs will swing through the Great Lakes region by the
middle of next week. A slow moving cold front will start to slide
into the Lower Great Lakes region and Ohio Valley region late
Tuesday night through late Wednesday night. Showers and
thunderstorms will become likely by the middle of next week.
Temperatures will also be slightly cooler with the rain chances in
the area Wednesday through early Thursday.
&&
.AVIATION /00Z Saturday THROUGH Wednesday/...
Mainly VFR expected through 00Z/Sun. Aloft, a weak trough axis
moves E`ward through our region between ~09Z/Sat and ~18Z/Sat.
Otherwise ridging precedes and follows the trough. At the
surface, a weak trough affects our region through ~12Z/Sat.
Thereafter, a weak ridge builds from the west and north through
00Z/Sun. Our regional surface winds trend variable around 5
knots through the TAF period. However, a NW`erly to NE`erly lake
breeze around 5 to 10 knots is expected to affect locations
within several miles of Lake Erie from ~15Z/Sat through 00Z/Sun.
This includes KCLE and KERI.
A few showers and thunderstorms with brief MVFR to IFR are
expected along/near a weak low-level convergence zone
accompanying the aforementioned surface trough, especially
before ~04Z/Sat. This convergence zone is expected to reside
near a KFDY to KMFD to KGKJ corridor. Fair weather is likely
region-wide after ~12Z/Sat.
Widespread low clouds and associated VFR ceilings early this
evening are expected to expand and lower via nocturnal cooling
amidst lingering low-level moisture. As a result, widespread
MVFR to LIFR ceilings are expected to develop by this late
evening or early Saturday morning. These low clouds are then
expected to scatter-out or dissipate via diurnal convective
mixing of the boundary layer tapping into drier air aloft late
Saturday morning or early afternoon. Widespread mist and fog,
and associated MVFR to LIFR visibility, are expected to develop
late this evening or early Saturday morning. Mist/fog should
then dissipate via the onset of diurnal heating by midday
Saturday at the latest.
Outlook...Non-VFR possible with periodic showers and thunderstorms
on Saturday, but especially Monday night through Wednesday.
&&
.MARINE...
Overall the weather forecast for Lake Erie will remain quiet this
weekend into early next week. High pressure will return over the
lake this weekend with a light northeast flow under 10 knots for the
weekend. A warm front will lift across the lake Monday with a return
of southeast flow over the lake. Southerly flow will continue to
increase up to 15 knots Tuesday and Wednesday ahead of a low
pressure system that will move through the Upper Great Lakes for the
middle of the week. No marine headlines are expected at this
time.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Dense Fog Advisory until 10 AM EDT Saturday for OHZ009>014-
019>023-089.
PA...Dense Fog Advisory until 10 AM EDT Saturday for PAZ001>003.
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...Garuckas/Jaszka
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Jaszka
MARINE...Griffin
Area Forecast Discussion
National Weather Service Corpus Christi TX
634 PM CDT Fri May 17 2024
...New AVIATION...
.SHORT TERM...
(Tonight through Saturday night)
Issued at 323 PM CDT Fri May 17 2024
Key Messages:
Drier tonight, warmer tomorrow
Current radar shows a couple lines of showers and thunderstorms
stretching from the Brush Country through the northern Coastal
Plains and into the Victoria Crossroads. The HRRR and other CAM
models continue to show redevelopment across the Coastal Plains and
Coastal Bend this afternoon, but confidence is low at this time as
the atmosphere appears to have stabilized in the wake of the cluster
of thunderstorms that moves through the region late this morning. If
we get enough breaks in the clouds and the atmosphere is able to
destabilize with daytime heating, then the confidence for
redevelopment will increase significantly. Rain chances across the
region should quickly taper off this evening after sunset as PWAT
values begin to decrease.
As the upper-level trough continues moving eastward tonight, some
vorticity will swing across the base of the trough and through South
Texas, however, with PWAT values decreasing and the forcing from the
upper-level jet dynamic no longer over South Texas, chances for
showers and thunderstorms will be low. Ridging will begin to move
into the region tomorrow promoting warmer temperatures. Despite PWAT
dropping to near 1" late tonight into tomorrow, sufficient moisture
will hang around to promote heat indices of 100-105 degrees area-
wide. There`s also a medium chance for patchy fog to develop from
the Brush Country through the Coastal Plains and into the Victoria
Crossroads as light winds will combine with the moisture from the
recent rainfall.
&&
.LONG TERM...
(Sunday through next Thursday)
Issued at 323 PM CDT Fri May 17 2024
Key Message:
A Major to Extreme risk of heat related impacts from dangerous
heat next week across most of South Texas
The long term period starts out with a mid-level high over Cuba and
another one just south of the tip of Baja, CA. A ridge builds in
over the region and keeps storm tracks further north as subsidence
builds in across most of the state. The lack of deep moisture
combined with subsidence will preclude any rain/storm chances
throughout the long term period despite increasing PWAT`s next week.
Precipitable water values start out below normal < 1.0" than onshore
flow increases low level moisture with PWAT`s of around 1.50-1.75"
according to the GEFS mean ensemble by the end of next week with
normal values for this time of year at 1.50".
Hot surface temperatures combine with high humidity resulting in
dangerous heat most of the week next week with Tuesday and Wednesday
looking to be the peak. Generally, there`s a Major risk of heat-
related impacts for anyone without effective cooling and/or adequate
hydration, much of the week with heat indices ranging up to around
110 degrees. Tuesday and Wednesday look to pose an Extreme heat risk
with heat indices 110-115 degrees across much of the region. This
level of rare and/or long-duration extreme heat with little to no
overnight relief affects anyone without effective cooling and/or
adequate hydration. Please take safety precautions and brush up on
how to combat the heat at weather.gov/safety/heat
&&
.AVIATION...
(00Z TAFS)
Issued at 621 PM CDT Fri May 17 2024
A few showers continue around the VCT area this evening, but will
be exiting over the next couple of hours. Storms in Mexico west of
COT and LRD are expected to diminish as they move toward the Rio
Grande, but mid/upper levels clouds left over from the storms
will likely continue to stream across S TX. MVFR CIGs are expected
mainly along the coast with VCT, CRP and ALI having periods of MVFR
CIGs over tonight. VSBYs are also expected to lower to MVFR/IFR
for these areas toward early Saturday morning between 09-14Z due
to patchy fog. The SREF is showing the probability of visibilities
less than 1SM between 30-50% from ALI to VCT and 10-20% across
CRP. VFR conditions are expected by mid morning Saturday with
much less cloud cover due to a ridge building across S TX.
&&
.MARINE...
Issued at 323 PM CDT Fri May 17 2024
Weak to moderate northeast flow this evening will weaken and drop
under 10 knots by midnight. Winds will remain weak at 10 knots or
lower through tomorrow night with the winds shifting to the
southeast tomorrow night. Low to medium chances for rain tonight
will drop to slim (less than 10%) tomorrow as an upper-level ridge
moves into the area. Weak onshore flow Sunday strengthens to weak
to moderate Sunday evening before becoming Moderate Tuesday
night. Weak to moderate onshore flow is expected to resume
Wednesday through the end of the week. Warm and dry conditions are
expected with Maximum Heat Index values 90-95F Tuesday through
Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 71 93 74 93 / 10 0 0 0
Victoria 66 93 72 93 / 10 0 0 0
Laredo 71 101 75 101 / 10 0 0 0
Alice 68 97 73 96 / 10 0 0 0
Rockport 74 89 77 88 / 10 0 0 0
Cotulla 68 100 73 101 / 10 0 0 0
Kingsville 70 95 74 94 / 10 0 0 0
Navy Corpus 77 89 77 89 / 10 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM...JCP
LONG TERM....BF
AVIATION...TE/81
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
835 PM CDT Fri May 17 2024
.KEY MESSAGES...
- Isolated showers and storms (15-30% chance) east of the Illinois
River through sunset this evening. Severe thunderstorms are not
expected.
- Fog development is likely tonight across eastern IL, with a 40-70%
chance of visibility falling below 1 mile east of I-55.
- Severe thunderstorms are possible next week on Tuesday and/or
Wednesday. The exact timing remains uncertain at this range.
&&
.UPDATE...
Issued at 835 PM CDT Fri May 17 2024
Isolated thunderstorms continue along a narrow line just south of
IL Rte 10 in Mason/Menard, Logan, DeWitt, Piatt, and Champaign
counties. Based on how these look on radar and in satellite loops,
thinking is they will diminish in next couple of hours. Then still
expecting clear skies through the night with fog developing in the
east and southeast parts of the CWA. Besides the isolated storms,
current forecast still looks good for the rest of the area. Update
should be forthcoming.
Auten
&&
.DISCUSSION...
Issued at 231 PM CDT Fri May 17 2024
** THROUGH SUNDAY **
A weakly forced pattern exists across IL this afternoon, with the
state sitting between lower sfc pressure in the northern Plains
and weak sfc high pressure over the mid-Atlantic. Vis sat shows
two corridors of more agitated Cu development at 140pm/1840z, one
from Quincy to Bloomington, and another from Shelbyville to Paris.
Forecast soundings suggested 1500-2000 J/kg of SBCAPE developing,
but with very weak shear (less than 20 knots), and that is well
aligned with the latest RAP-based mesoanalysis. Given the weak
forcing those two aforementioned corridors of enhanced Cu will be
the favored area for any storm development over the next few
hours. Given the weak shear, these will be short-lived, and that
matches what we`ve seen with the few cells that have developed
thus far. As we progress later into the afternoon, the forcing
could become a little more nebulous, with a collapsing cell
producing outflow that kicks off new cells, and so on. With the
potential for that kind of messy evolution, maintained a 15-30%
PoP east of the IL River through sunset, after which point any
lingering cells will quickly diminish.
Another round of fog development is possible tonight, including
some dense fog, owing to a combination of light winds and mostly
clear skies. Guidance has been consistent in showing the chance of
fog increasing with eastward extent. 12z HREF guidance had a
40-70% chance of vis falling below 1 mile east of I-55 tonight,
while the available runs of the HRRR that go out far enough show
dense fog development near/east of I-57.
For the weekend, central IL will be positioned between a sfc low
over south-central Canada and a weak shortwave moving through the
lower TN Valley. In between these two systems, upper level height
rises occur over IL, resulting in mostly dry conditions and
steadily warming temps. CAMs do show storm development Sat
afternoon along the cold front associated with that Canadian sfc
low, but it will be positioned across WI and IA, and the activity
fades in the evening with the loss of heating before reaching the
ILX CWA.
Previously, there had been high confidence that Sunday would be
dry area-wide, but now guidance is showing storms developing over
east CO Sat night and progressing east along the instability
gradient, which puts it on a track towards west-central IL by Sun
afternoon, if it holds together. For now, the NBM introduced
15-20% PoPs which seemed reasonable given the uncertainty in the
evolution of a convective complex at this range. Shear values look
quite weak across our area Sunday, with deep layer shear values
again below 20 knots.
Temperatures do become quite warm on Sat-Sun, with highs in the
mid to upper 80s which is about 10-15F above normal. Record highs
for Sunday (May 19) are around 92-93F, and at this point it looks
unlikely that we`ll breach those thresholds.
** EARLY NEXT WEEK **
A trough is set to amplify over the western US and send a low
racing towards from the central Plains to the upper Midwest on
Tuesday. Multiple days of gulf moisture advection in advance of
this system will help push dewpoints near or into the low 70s. The
warm-sector associated with this system continues to appear quite
volatile, but mesoscale details and timing uncertainties
remaining regrading the svr threat. From an ensemble perspective,
the latest GEFS shows a 70-90% chance of exceeding 2000 J/kg of
SBCAPE. CWASP (a parameter which combines numerous environmental
factors related to severe weather into one index) is depicting
values over 70 west of I-55 Tues afternoon. For reference, most
EF2+ tornadoes occur in environments with CWASP values over 70.
It needs to be emphasized that CWASP is just a summary of the
environment, it does not factor in whether or not storms will be
present in that environment. In that regard, it does look like the
latest guidance has trended a bit slower with the cold front,
such that the higher threat may be focused in areas west of the
ILX CWA Tues afternoon. The previous forecast from the NBM had
PoPs Tuesday afternoon around 60%, but the latest forecast ranges
from 30% along I-70 to 60% NW of the IL River. PoPs across the ILX
CWA peak during the Tues night time frame (60-80%). It`s too
early to say how the severe threat could evolve into the Tues
night timeframe, but perhaps the diurnal timing could be our
saving grace from a higher-end severe weather outbreak. The flip
side to a slower system is that it could mean a greater portion of
the area is at risk for severe storms on Wednesday. With several
days of convective activity needing to evolve between now and
then, confidence in placement of storms on Wednesday is low, and
SPC did not introduce a Day 6 Outlook area in this morning`s
forecast.
In summary, there is a chance for severe thunderstorms both
Tuesday and Wednesday - with the latest guidance suggesting
precip/severe chances increase with northwestward extent Tues
afternoon, then storms push into the ILX CWA Tues evening/night.
High temps remain in the 80s through Wed, then cool into the 70s
for the latter half of the work week following FROPA.
Erwin
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 640 PM CDT Fri May 17 2024
VFR conditions will prevail at PIA, SPI, and BMI for the next
24hrs with clear skies or scattered mid clouds at BMI due to some
evening convection that is south of the site. DEC and CMI will
also see clear skies or scattered mid clouds for the same reason
as BMI. Some CU is expected tomorrow around 2.5kft at BMI, SPI,
DEC, and CMI, but only scattered. The main concern will be fog at
DEC and CMI during the morning hours with CMI seeing the lowest
possible vis of 1.5 miles. Winds will be light and variable
through the night and then be southerly tomorrow but still below
7 kts.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Jacksonville FL
901 PM EDT Fri May 17 2024
...TORNADO WATCH IN EFFECT UNTIL 1AM...
...New UPDATE, AVIATION...
.UPDATE...
Issued at 900 PM EDT Fri May 17 2024
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
A Tornado Watch will be in effect until 1 AM for areas north of
the I-10 corridor west of the JAX metro area and as the Suwannee
Valley Region in NE FL, and spanning northward into SE GA towards
Waycross, GA. Aside from tornadoes, wind gusts of up to 70 mph
will be possible as well as large hail.
&&
.NEAR TERM...(Through Tonight)
Issued at 245 PM EDT Fri May 17 2024
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
Another round of thunderstorms will impact the area this evening,
primarily north of I-10. Convective models had a hard time pin-
pointing the timing, but as of now it looks like storms will be
entering the interior SE GA counties around 7-8pm, with things
fizzling out just after midnight. With the sun peaking out of the
clouds, enough instability will allow for strong to severe
thunderstorms this evening, with the primary hazards being
damaging winds and hail, but an isolated tornado and heavy
rainfall cannot be ruled out.
Heavy cloud cover and southerly flow overnight will keep mild
lows in the lower 70s. Patchy fog will be possible over north
central Florida early Saturday morning given calm winds and
increased moisture.
&&
.SHORT TERM...
(Saturday through Sunday night)
Issued at 245 PM EDT Fri May 17 2024
A frontal boundary will be just to our north Saturday morning
while a trough of low pressure aloft moving over the region. CAM
models suggest a organized cluster of storms will moving west to
east from AL, FL panhandle, and south GA, but differ substantially
on the timing. The HRRR brings in convection fairly early during
the day but in general the HREF suggests more of a midday arrival.
There is more than sufficient instability available and 0-6 km
shear generally in the 40-50 kt range. The convection, if it
develops earlier in the day, may allow for a quieter afternoon
as the airmass will be overturned from the convection. Overall
confidence is low to moderate on the timing. There is a risk of
some of these storms to become severe given the combination of
shear and instability. We can`t rule out an isolated tornado
threat.
Further south away from the front, southwest winds will be gusty
at 15G25mph. Max temps could top out in the lower 90s over areas
of northeast FL with resultant heat indices near 100. The front
looks to bisect the forecast area Saturday evening from southwest
to northeast then continue to sag southward as mid level troughing
digs southeast into the region. This will continue to support
elevated rain chances Saturday night.
Sunday, the front looks positioned over parts of northeast FL with
scattered to numerous showers and storms still possible, as upper
level vort lobe swings over the area. We continued high POPs still
at about 60-70 percent, which may be a little generous. Chance of
showers and a few storms lingers as a surface trough/reinforcing
front pushes through from north to south.
&&
.LONG TERM...
(Monday through next Friday)
Issued at 245 PM EDT Fri May 17 2024
A relatively benign weather pattern looks in store for most of
this period with mainly dry post-frontal airmass dominating.
There may be a few lingering showers or a storm southern most
areas Monday before the front clears the area to the south. The
nose of sfc high pressure then expected to persist across the
Carolinas and GA before moving over our forecast area Wed and
Thu. Another cold frontal boundary will then move into the
southeast states, possibly into north GA by Thursday. Will have
some low POPs for southern zones on Monday but at most 10-20
percent chances rest of the period. The cooler airmass immediately
behind the front Mon and Tue and the northeast low level flow
will let highs be in the 80s, with about 80 or so at the coast due
to northeast winds. However, temps ramp up again Wed and Thu to
upper 80s and lower 90s as high pressure will be over the area
and upper level ridge will near us. For now on Friday, just
slight rain chances with persistent warming temps in the lower to
mid 90s, with the weak cold front likely remaining to the north
still.
&&
.AVIATION...
(00Z TAFS)
Issued at 900 PM EDT Fri May 17 2024
Rain will move into the area through the early evening hours
affecting mainly the northern TAF sites during the early part of
the TAF period, clearing out a bit past midnight. The next round
of showers and storms will look to get going during the afternoon
tomorrow, with timing still uncertain.
&&
.MARINE...
Issued at 245 PM EDT Fri May 17 2024
Weak high pressure will linger rest of today before a weak area
of low pressure lifts to the north tonight. A warm front will push
north over the area waters. A slow moving cold front trailing the
low will gradually push across the water late Saturday through
Sunday, renewing chances for thunderstorms. Winds will turn
northerly as high pressure wedges against a low pressure situated
northeast of the waters early next week. At this time, confidence
in any small craft advisory is low from northerly flow. High
pressure builds directly over the waters during the middle part of
next week.
Rip Currents: Low surf and weak winds will keep a low risk of rip
currents at area beaches.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 72 87 68 85 / 80 80 70 60
SSI 73 88 70 85 / 40 60 80 60
JAX 73 92 70 87 / 20 40 70 70
SGJ 73 94 70 87 / 10 30 70 80
GNV 71 91 69 86 / 0 40 70 80
OCF 73 92 71 85 / 0 30 60 80
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Area Forecast Discussion
National Weather Service New Orleans LA
637 PM CDT Fri May 17 2024
...New AVIATION...
.SHORT TERM...
(This evening through Saturday night)
Issued at 428 PM CDT Fri May 17 2024
Convection has struggled to develop so far today (and we aren`t
complaining). A special 18Z RAOB sounding from KLIX shows a
subsidence inversion near 850 mb in wake of last night`s MCS that
has helped to cap convection thus far. We are closely monitoring for
convection to initiate along the quasi-stationary frontal boundary
that is located just south of a line from Lafayette to Baton Rouge
to Hattiesburg. This boundary has become increasingly better-defined
as differential heating has magnified the temperature gradient
(upper 60s/lower 70s on the cool side of the boundary and mid 80s in
the warm sector). Low-level convergence has also strengthened near
the front and this will provide a source of lift, but appears to be
too shallow for convective updrafts to reach the LFC. Recent
satellite trends show the CU field is building just south of the
warm front along the Southshore, Coastal MS, and parts of coastal
southeastern LA. This is the area where storms are most likely to
initiate through mid afternoon. Expect coverage of storms to be
widely scattered given the absence of deeper forcing. However,
any storms that to break the cap has the potential to quickly
become severe with an EML overhead and strong instability rooted
in the boundary layer. These storms will be capable of producing
locally damaging winds (favorable wet microburst environment with
high instability and mid-level dry air) and large hail (steep mid-
level lapse rates).
The severe weather and flash flood risk quickly ramps up overnight.
This is when strong forcing for ascent overspreads the area as a
upper shortwave trough approaches from the Southern Plains and the
region becomes located in the right entrance region of an upper-
level jet streak. The afternoon cap erodes, allowing robust
convection to initiate and grow upscale along the aforementioned
frontal boundary. The severe and heavy rainfall threat has shifted
slightly farther south given the position of the stationary front
and anticipated southeastward movement of it tonight. This takes
the northwestern portion of the CWA out of the primary severe
wx/heavy rainfall threat area. CAMs are in good agreement showing
storms quickly growing upscale and intensifying around 1 or 2 AM
as the boundary progresses south of I-12. This would place the
Southshore and coastal MS/SE LA under the greatest risk for heavy
rainfall and severe weather during the 2-8 AM period.
Similar to last night, the greatest severe weather threat will be
damaging winds. It should be noted that the HRRR runs today has
consistently been showing intense winds near 80 kt with the
convection near the SE LA coast.
There is some uncertainty regarding where the heaviest rain falls,
but localized amounts of 3-4" will be possible. This will be
enough to produce another round of flash flooding, especially in
areas that are already saturated from the previous rounds of heavy
rainfall last night and back on Monday. There was enough
confidence to drop the Flood Watch for areas north and west of
Baton Rouge. Meanwhile the Flood Watch was expanded a tier of
zones southward to include Houma and Thibodaux but not quite all
the way down to the LA coast. The watch was also extended through
midday Saturday as it the storms will be slow to move offshore.
&&
.LONG TERM...
(Sunday through Thursday night)
Issued at 428 PM CDT Fri May 17 2024
Dry northwesterly flow aloft will be the main driver of the weather
to start the long term period. An H5 shortwave ridge axis to our
west will help transition the region into a much drier pattern
overall. This pattern sets in through at least midweek as upper
level heights and thicknesses increase over the region. This will
help most if not all of the CWFA eventually warm into the 90s
sometimes early to midweek during peak heating. At the surface, high
pressure will begin to move east across the southern Appalachians
allowing for a moisture rich onshore flow to begin across the
region...so overnight lows too will start a modest warming trend as
low level moisture begins to quickly spill northward from the Gulf
by Tuesday.
Warm and dry conditions should continue for Wednesday and Thursday
as a 594dam ridge continues to reside over northeast Mexico or Deep
South Texas. The ridge will extend northeast along the US Gulf Coast
and again this favors a hot pattern across the region. Up stream a
surface front will try to move southward on Thursday. Globals don`t
seem to agree with the progression of the front. GFS is a bit more
bullish with pushing the frontal boundary through the region despite
questionable upper levels (parent trough continues downstream pretty
quickly). For this solution to be applicable, would expect strong
convective cold pool forcing to give the front more motivation,
which given the QPF is more aggressive on the GFS is plausible. ECM,
however, keeps most of the QPF signal well north of our region
across the Mid South. This solution doesn`t have the front move
through the region...which is also a drier and warmer solution.
Regardless, this is still a week out so we will hurry up and wait
and see what eventually evolves through early to midweek next week.
For now, lower tier POPs for the northern tier seems reasonable.
&&
.AVIATION...
(00Z TAFS)
Issued at 623 PM CDT Fri May 17 2024
Frontal boundary across the middle of the CWA this afternoon has
produced rather variable conditions across the terminals, ranging
from IFR at KMCB to VFR at several terminals south of the
boundary. The primary condition this evening should be MVFR
ceilings, with a comparative lack of precipitation. As a shortwave
approaches from the southwest late this evening scattered to
numerous SHRA/TSRA will move across most of the terminals from
southwest to northeast. Direct impacts are likely to produce IFR
or lower conditions, primarily visibilities. Wind gusts to 30-40
knots will be possible with the stronger storms, and can`t rule
out higher gusts. Precipitation should begin to wind down by mid-
morning Saturday, with VFR conditions expected by afternoon.
&&
.MARINE...
Issued at 108 PM CDT Fri May 17 2024
The strongest winds thus far today has been present across the far
southeastern coastal waters, but even here observations marginally
support a SCA with occasional gusts to 20 kt. Winds have actually
become light over the lakes where the pressure gradient is light
near a stationary boundary.
Isolated thunderstorms are expected to develop near the coast late
this afternoon and early evening. Although coverage will be
limited, any of these storms have the potential to produce
locally strong winds in excess of 34 kt, large hail, heavy
downpours, lightning, and higher seas. The risk of hazardous
conditions on the waters will increase overnight and continue
through Saturday morning as storms organize along the front and
move southward. Some of our model guidance is showing the
potential for intense convective wind gusts in excess of 50 kt,
perhaps locally to hurricane strength.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 66 84 65 88 / 60 30 0 10
BTR 70 87 70 93 / 70 30 0 0
ASD 69 84 69 92 / 70 70 0 10
MSY 71 84 73 90 / 80 70 0 10
GPT 69 81 69 89 / 80 80 10 10
PQL 69 82 67 91 / 70 80 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Small Craft Advisory until noon CDT Saturday for LAZ068.
Flood Watch through Saturday morning for LAZ036-037-039-046>048-
056>060-064-065-071-076>090.
GM...Small Craft Advisory until noon CDT Saturday for GMZ530-532-534-
536-538-550-552-555-557-570-572-575-577.
MS...Flood Watch through Saturday morning for MSZ077-083>088.
GM...Small Craft Advisory until noon CDT Saturday for GMZ532-534-536-
538-550-552-555-557-570-572-575-577.
&&
$$
SHORT TERM...JK
LONG TERM....RDF
AVIATION...RW
MARINE...JK
Area Forecast Discussion
National Weather Service Marquette MI
650 PM EDT Fri May 17 2024
.KEY MESSAGES...
-Breezy south winds and very warm temps in the 70s and 80s Saturday
ahead of a cold front that will bring scattered afternoon/evening
thunderstorms. The strongest storms may contain small hail.
-Borderline elevated fire weather expected this weekend with breezy
conditions on Saturday then very dry with light winds on Sunday.
-More rain chances early to middle of next week as a series of
disturbances moves across the area in a developing warm and moist
southerly flow.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 346 PM EDT Fri May 17 2024
Water vapor imagery and RAP analysis show that the shortwave trof
that brought shra to the area yesterday thru last evening has lifted
across northern Ontario. In the wake of that wave, westerly flow
prevails into Upper MI. An area of sct -shra has been moving out
across western Lake Superior to the Keweenaw in an area of
waa/isentropic ascent. The -shra that have reached the Keweenaw are
really not much more than sprinkles. Elsewhere, skies cleared out
quickly in the morning, but daytime heating led to a blossoming of
cu. Stabilizing marine layer off of Lake MI and Lake Superior are
evident, preventing cu. Temps have risen into the low/mid 70s F in
the interior. Closer to the Lakes, temps range down into the 50s
with some 40s F at lakeside locations along Lake Superior.
Aforementioned waa/isentropic ascent will continue to support some
-shra/sprinkles across the Keweenaw over the next few hrs. MLCAPE
has increased to 100-200j/kg into far western Upper MI. This limited
instability may support development of a few shra/tsra late
aftn/early evening, less than 25pct chc. During the night, vigorous
shortwave that is now over nw MT will swing out to ND. While the
main low-level jet in response to this wave will develop ne thru MN
during the night, there will be a modest increase in 850mb winds
further ne across western Lake Superior this evening. The resulting
increase in waa/isentropic ascent should yield some shra/tsra later
this evening across northern portions of western Lake Superior and
possibly also nw Upper MI, mainly the Keweenaw where fcst reflects
30pct chc. Shra/tsra associated with the main 40-50kt low-level jet
developing across MN would reach western Lake Superior late tonight.
Expect min temps tonight ranging from the lower 40s on the east side
of the Keweenaw and near Lake MI to 55-60F in the southerly wind
downslope areas far w (Ontonagon/Gogebic counties).
&&
.LONG TERM /SATURDAY THROUGH FRIDAY/...
Issued at 523 PM EDT Fri May 17 2024
Highlights of the extended forecast include very warm conditions
this weekend with the potential for strong thunderstorms and
elevated fire weather conditions at times. Focus shifts to
widespread rain potential early/mid next week in addition to a
transition to below normal temperatures by late next week.
Beginning Saturday, the UP will be squarely in the warm sector of a
surface low near Lake Winnipeg with 850 mb temps of 14-16C spreading
across the UP. This unseasonably warm air mass will support high
temps in the lower to mid 80s with the highest readings (84F+) for
downsloping areas along west-central portions of our Lake Superior
shoreline. Breezy south winds in the tightening gradient ahead of
the approaching frontal boundary could gust as high as 30-35 mph,
especially for areas favored by southerly downsloping across Gogebic
and Ontonagon Counties. Southerly winds off Lake MI keeps the
eastern UP mostly in the 70s to perhaps even 60s closest to Lake MI.
ECMWF EFI highlights the unseasonably warm temps well, and like the
model soundings, also hint at the possibility of unseasonably strong
winds across the far west. The combination of hot temps and
gusty winds indicates borderline elevated fire wx conditions
with the main limiting factor being RH values mainly staying
above 30%. However, it`s worth noting that recent RAP/HRRR guidance
mixed deeper than regional/global models allowing for stronger
winds and lower RHs below the 30% threshold, but was not
confident enough in those solutions at this time.
Timing of the incoming cold front appears increasingly favorable for
thunderstorm chances across the western UP Saturday evening. The
latest HREF means show QPF moving into the Ironwood area 20-21Z,
with hourly rainfall rates peaking about 1-2 hours later (~6 PM).
Strong frontal forcing should produce a narrow line of storms
that steadily marches east suggesting peak rainfall rates may
provide more accurate timing. The peak rates reach the Marquette
area around 3Z (11 PM) then exit the eastern UP around 8Z (4
AM). MLCAPE values increase into the 500-1000 J/kg range in a
narrow corridor ahead of the front with 30+ kts of bulk shear
indicating potential for a few stronger storms. The SPC outlooked
western portions of our area with 5% chances for large hail and
damaging winds accordingly. It`s worth noting the 12/18z HRRR
runs that developed strong outflow wind gusts in the vicinity of
the Porcupine Mountains, but that may be an artifact of the
deeper mixing mentioned above.
A much drier air mass and associated surface ridging follows the
frontal passage for Saturday night into Sunday. Abundant sunshine
and light winds will result in deep mixing into extremely dry mid-
levels on Sunday. For example, the 12z NAM fcst sounding valid at
18z Sunday in Ironwood indicated a -40C dew point at 779 mb.
Fortunately, surface dew points won`t mix that low, but still
incorporated the local mixed dew point tool to cut back on Td values
resulting in min RHs closer to 20% across the interior portions of
the cwa. The good news is light winds less than 10 mph should ease
fire wx concerns, because critically low RHs appear nearly certain
across interior portions of the UP. Lake breeze activity should
limit fire wx concerns along the shorelines due to cooler temps in
the 60s and higher RHs. Expect max temps reaching near 80F over much
of the interior west half and mid to upper 70s over the interior
east half.
Models advertise a mid-level trough amplifying over the western
CONUS early next week. Periodic shortwaves in a warm/moist sw flow
developing ahead of the western CONUS trough will bring more rounds
of showers into the area early to mid next week. The first shortwave
moves through late Sun night into Monday bringing the initial batch
of showers for early next week. It looks like the best chance for
widespread and possibly heavy rainfall will be in the late Tue into
Wed time frame when models indicate more substantial shortwave
energy lifting across a nearly stationary frontal boundary draped
across the area. Model uncertainty increases later into the week but
it certainly looks possible that some scattered showers could linger
at least into Thursday as temps trend cooler in the wake of the
midweek low pressure system/frontal boundary pushing off to the
east.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 649 PM EDT Fri May 17 2024
VFR will prevail thru this fcst period at IWD/CMX/SAW. Pcpn
associated with a cold front will move into IWD and CMX late in the
period. Gusty winds to 20+kt will then set in at IWD and CMX mid to
late morning on Sat.
&&
.MARINE...
Issued at 523 PM EDT Fri May 17 2024
Stable conditions leads to light winds of generally 20 knots or less
continuing into early next week, except for Saturday afternoon and
evening when southerly gusts of 20-25 kts are forecast ahead of an
approaching cold front. Thunderstorms are possible this evening over
western and north-central portions of Lake Superior as a warm front
lifts across the lake. More thunderstorms are likely on Saturday
into Saturday night as the same system`s cold front moves across the
lake. These storms may contain small hail, gusty and erratic winds,
and frequent lightning. More thunder chances return late Sun night
into Monday and then again late Tuesday into Tuesday night as a
series of disturbances track northeast across the Upper Great Lakes
region. Patchy fog is occurring over eastern portions of the
lake and may become locally dense in areas of rainfall until
the cold front brings a much drier air mass over the lake
Saturday night.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...EK
AVIATION...07
MARINE...EK
Area Forecast Discussion
National Weather Service Norman OK
1059 PM CDT Fri May 17 2024
...New AVIATION...
.SHORT TERM...
(This evening through Saturday)
Issued at 301 PM CDT Fri May 17 2024
Our upper trough will be exiting to the east through today with
ridging building in behind it setting us up for a heating trend
starting Saturday. The stalled surface boundary/cool front has
washed out with a broad dryline stretched lee of the Colorado/New
Mexico Rockies. Will maintain POPS across southeast Oklahoma this
afternoon through early evening as embedded vorticity in the
trough of the wave could initiate isolated elevated storms.
Although weak in intensity, forecast sounding showing sufficient
high-based instability (above 800 mb) for convection although
shear is very weak for any organization or going severe. Visible
satellite imagery was already showing some cyclonic circulation
with the cloud cover over southeast Oklahoma while the latest
three HRRR runs suggesting isolated convection.
With no surface boundaries coming through, our surface moisture
won`t be going anywhere so expect temperatures tonight to cool to
the dewpoint (lower 60s) enhanced by clear night skies and
light/calm winds. As a result, could see some radiational fog
develop by mid-morning mainly east of I-35. Although much of the fog
should be patchy, there could be some embedded areas going dense.
Any fog should that develops should burn off shortly after sunrise.
As previously mentioned, pressure heights will start rising Saturday
as an upper ridge start building in and under sunny skies afternoon
temperatures will heat about 10 degrees warmer than today with highs
in the lower 90s across our western CWA to the upper 80s to the
east.
&&
.LONG TERM...
(Saturday night through next Thursday)
Issued at 301 PM CDT Fri May 17 2024
Gusty south winds return Sunday as well as the the dryline
sharpening up across the Panhandles through west Texas as surface
moisture increases across our area. Will see much of our western
and northern CWA warm well into the mid 90s and although
conditional, could see some convection develop east of the dryline
by late afternoon but due to uncertainties with instability strength
just east of the dryline will keep them very low (14-18%) but
mentionable for now. Although the GFS is the weaker solution with
respect to surface based instability, the ECMWF is much more
aggressive in the moderate (3000 J/kg) range while deep-layer shear
will be sufficient for organized severe convection in a most likely
uncapped environment. The mid-level cap strengthens closer to I-35
so will keep POPs and the marginal severe risk for Sunday afternoon
across all of western Oklahoma into a few of our adjacent western
north Texas counties with large hail & damaging wind gusts as the
potential severe hazards. If convection off the Southern High
Plains does not initiate, then have a higher chance for storms with
an MCS developing across Kansas through northern Oklahoma late
Sunday as a shortwave digs through the westerlies. For this system,
will have up to 40% POPs for elevated storms overnight extending
down to I-40. Can`t rule out a few strong to marginally severe
storms overnight as well.
A persisting tight surface pressure gradient will maintain windy
conditions Sunday night into Monday with a low-level jet developing
through the night. Mixing into the jet late Monday morning could
result in 30-35 mph gusts during the afternoon, and perhaps higher
should the GFS solution be correct verses a weaker ECMWF solution
with the strength of the jet in the afternoon. Our heating trend
will peak on Monday afternoon with all of our CWA rising well in the
90s, to upper 90s across our western CWA. Both models in agreeance
with the dryline punching into western Oklahoma during the
afternoon. It will feel quite muggy as well ahead of the dryline
with those upper 60s dewpoints, although windy conditions might
bring some relief from it. Our upper ridge is scooted out on
Tuesday with a broad trough digging through from the west, pushing
our next cold front and the dryline through late into Wednesday.
This will bring a return of storm POPs late Tuesday mainly along and
east of I-35 along with a severe risk. This cold front may lift
back through our area as a warm front on Thursday so will maintain
POPs widespread for late next week. Although temperatures should
be cooler more in the 80s after Tuesday, afternoon temperatures
still trend warmer than climatically average through the end of
next week.
&&
.AVIATION...
(06Z TAFS)
Issued at 1025 PM CDT Fri May 17 2024
VFR conditions to continue.
Light south winds and clear skies expected through the forecast
period. There is some possibility of fog late tonight at DUA, but
chances remain too low to introduce into TAF at this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 61 88 65 90 / 0 0 0 0
Hobart OK 61 92 65 93 / 0 0 0 20
Wichita Falls TX 62 92 66 93 / 0 0 0 10
Gage OK 59 93 63 95 / 0 10 10 20
Ponca City OK 59 88 63 89 / 0 0 0 10
Durant OK 62 89 65 90 / 10 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...68
LONG TERM....68
AVIATION...30
Area Forecast Discussion
National Weather Service Salt Lake City UT
247 PM MDT Fri May 17 2024
.SYNOPSIS...An active, unsettled pattern will continue through at
least the first half of next week.
&&
.SHORT TERM (Through 12Z Sunday)...Another summer-like day here
across the Beehive State as we head into the weekend. A mainly dry
cold front has progressed through most of northern Utah, with
gusty northwesterly winds in its wake. Near the front, isolated,
high-based showers have formed. Given the deep, dry sub-cloud
environment, cant rule out out a few microbursts this afternoon
and evening...mainly south of Provo.
As the initial shortwave trough shifts east into the Plains, the
next shortwave trough will dig southeastward into the Pacific
Northwest. In response, the remnant cold front will begin to lift
north as a weak quasi-warm front. This boundary will support
isolated to widely scattered high-based convection across portions
of northern and central Utah Saturday afternoon into Saturday
evening. A significant portion of the guidance envelope continues
to support high-based convection moving into northern Utah
Saturday night into Sunday morning. The main impact will be the
continued potential for dry microbursts, especially during the
daylight hours.
.LONG TERM (After 12Z Sunday)...As we pivot to more unsettled
weather this weekend, the main hazards for the long-term period
include below-normal temperatures and isolated to scattered
showers and thunderstorms, especially for northern Utah and
southwest Wyoming.
A longwave trough will push southward from the Interior Northwest
and into northern Utah by Sunday. An overall lack of moisture and
dynamics on Sunday will produce only isolated
showers/thunderstorms over higher terrain during the afternoon and
evening across northern areas. By Monday, a surface cold front
will be making its way across Utah, with a slight increase in
moisture and more showers/thunderstorms likely along that
baroclinic zone, especially during the afternoon. Far southern
Utah could see some breezy southwesterly winds Monday afternoon
ahead of that frontal passage. While the main cold front will have
moved eastward by Tuesday, lingering instability will likely also
produce scattered showers and thunderstorms on Tuesday afternoon,
particularly over higher terrain and northern areas once again.
As for temperatures, highs on Monday are likely to be 10-15
degrees cooler than Sunday across many areas, with far southern
Utah highs only decreasing by around 5-10 degrees. The main
uncertainty here is with the track of the trough, with a more
southern track (50% of ensemble members) likely producing cooler
temperatures further south. A shallower trough (26% of members)
would likely limit the degree of cooling over southern Utah.
After a shortwave ridge on Wednesday with a warming trend,
another trough is possible later in the work week. Currently, 54%
of ensemble members favor a stronger trough which could produce
even cooler, unsettled weather. The remaining 46% of members favor
a far weaker trough and less active weather.
&&
.AVIATION...KSLC...Northwest winds are forecast through this
evening before shifting out of the southeast overnight. A light
northwest wind can be expected once again early tomorrow
afternoon. VFR conditions will prevail.
.Rest of Utah and Southwest Wyoming...VFR conditions are forecast
throughout the period across the region. Isolated rain showers
are forecast for tomorrow afternoon, mainly across any central
Utah terminals. Areas of gusty winds are noted this afternoon
which will decrease during the evening and are forecast to be
light overnight. There is, however, a chance for stronger winds
after midnight at southern Utah terminals as indicated by the RAP
and HRRR model solutions. Gusts around 30 knots are possible if
these solutions come to fruition.
&&
.FIRE WEATHER...Isolated high based convection continues to
develop near and ahead of a cold front this afternoon...roughly
near a line from Ibapah to Uinta County WY. Gusty winds are
occurring behind this front, highest across areas of northern Utah
closest to the Wyoming border. This front will gradually weaken
through this evening as the best support lifts away from the
area...and then gradually lift north as a pseudo-warm front
through Sunday. Chances of high-based convection will increase
with this front and continue into Sunday. Additional troughs will
bring unsettled conditions into the next week.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&
$$
Kruse/Cunningham/NDeSmet
For more information from NOAA`s National Weather Service
visit... http://weather.gov/saltlakecity