Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/30/19
Area Forecast Discussion
National Weather Service La Crosse WI
620 PM CDT Wed May 29 2019
.SHORT TERM...(Tonight through Thursday Night)
Issued at 252 PM CDT Wed May 29 2019
At 2 PM, a 700-600 mb frontogenetic band continues to produce a band
of showers north of Interstate 94 this afternoon. The meso models
show that this band will slowly weaken late this afternoon. Due to
this, went with deceasing rain chances through the remainder of the
afternoon.
For tonight and Thursday, an opening closed low/trough, currently
located over west-central Iowa, will move east across Iowa and
northern Illinois. As this occurs, the 850-700 mb frontogenesis will
increase. With ML CAPES of 1000-1500 J/kg, expect a band of showers
and scattered thunderstorms to develop this evening and then
continue into Thursday morning. With 0-3 km shear less than 35
knots, not anticipating any severe weather. Rainfall amounts will
be up to a half inch. Waning of the showers is expected in the
afternoon as the trough drops southeast of the area. Meanwhile,
increasing northwest flow aloft will usher in a weak embedded trough
and a chance of showers/isolated storms into the area late Thursday
afternoon into Thursday evening. Otherwise, plan on highs Thursday
in the mid/upper 70s amd lows Thursday night in the 50s.
.LONG TERM...(Friday through Wednesday)
Issued at 252 PM CDT Wed May 29 2019
Northwest flow aloft continues Friday into the weekend. A low drops
southeast in the flow Friday with models in excellent agreement on
the track mainly northeast of I-94. This will put us in the warm
sector with southwest flow/downsloped air from the Plains moving in.
NAM showing 925mb temperatures warming to near 25C. This is expected
to push highs well into the 80s. Meanwhile there will be some
increasing elevated/2-7km MUCAPE into the 1000-2000J/kg range as a
cold front pushes in from the northeast later in the afternoon/
Friday night. Bufkit showing this elevated instability as well with
an inverted-v look to it. Shear will be weak though, generally in
the 15-20kt range. So, thinking sub-severe storms at this point if
any do form with possibly some gusty wind and small hail.
Cooler air filters in behind the cold front Saturday with highs
topping off in the upper 60s to the middle 70s. Could also see some
lingering shower/isolated thunderstorm chances mainly in the morning
as that frontal boundary slides south through the remainder of the
area.
High pressure builds in Sunday for some much-needed drier weather.
Look for pleasant temperatures in the upper 60s to lower 70s.
Shower and thunderstorm chances return to the area Monday afternoon
and linger through Wednesday as low pressure slowly makes its way
across the Northern plains into our region. Temperatures meanwhile
look to be right around seasonal norms with highs in the upper 60s
to upper 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 620 PM CDT Wed May 29 2019
Cigs: tricky forecast with most models nudging low level saturation
(and MVFR cigs) right up the TAF sites tonight. Latest RAP more
aggressive with northward movement and suggest several hours of MVFR.
For the moment, will hold with current forecast (VFR). Will monitor
and update if northward trends win out.
After low pressure exits east early Thu morning, mostly sct-bkn high
level clouds for Thu.
WX/vsby: inverted trough/elevated frontogenetic region north of low
passing west-east south of the local area tonight will fire up
shra/ts tonight. HRRR/RAP keep this activity south of I-90.
Winds: mostly light/vrb tonight, becoming northwest Thu morning will
passage of low.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Boyne/DAS
LONG TERM...DAS
AVIATION...Rieck
Area Forecast Discussion
National Weather Service Hastings NE
613 PM CDT Wed May 29 2019
.SHORT TERM...(This evening through Thursday)
Issued at 319 PM CDT Wed May 29 2019
Aloft: RAP tropopause analyses and WV imagery shows a complex
split flow over the CONUS. A high was over the Canadian Prairies
with a trof underneath over the Wrn USA. The low that mvd into NEB
yesterday was near FSD with a trof extending SW acrs NEB.
Spaghetti plots show the low will inch S to OMA by 12Z/Thu and
then weaken as it heads SE to MO/IL tomorrow. The trailing trof
will then sink to the NEB/KS border by 00Z/Fri. Meanwhile...the
high over Canada will mv SE into the Nrn Plns.
Surface: Low pres was over IA and mvg away from the rgn. Weak
1016 mb High pres was over WY. This high will gradually slide SE
and be over Wrn KS/OK/TX tomorrow.
Rest of this aftn: P-M/cldy. There might be a few very low-top
shwrs form. High temps will be around 5 PM...in the 60s. About 10F
below normal.
Tonight: P-M/cldy. A few light shwrs will be psbl as the trof mvs
in. Gvn disagreement in timing/location in the simulated mdl
reflectivity...did not get fancy with POPs. Lows around 50F.
Thu: M/sunny to p/cldy at times. Still could see a few light
shwrs with the upr trof. Warmer with near normal highs in the upr
70s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 319 PM CDT Wed May 29 2019
Aloft/Pattern: The persistent/blocked Wrn trof/Ern ridge over the
last 10 days will finally breakdown. By mid next wk...a pattern
more typical of summer is fcst to evolve with the primary band of
Westerlies along the US-Can border. Spaghetti plots of the last 2
runs of the UKMET/EC/GFS/GFS-FV3/CMC are tightly-clustered on this
scenario...allowing good confidence. That means overall warmer
and drier wx here.
There are svrl shrtwv trofs embedded within the Wrn longwave
trof. One is currently along the Srn CA coast will mv inland...
round the base of the Wrn trof and cross NEB/KS Fri AM. This trof
will be of little consequence. Another vort max currently near the
intersection of UT/WY/CO is fcst to become mobile and cross SD
Fri night. That trof should be of little consequence as well. A
clsd low will form over OR today...drop into Srn CA Fri and become
cut-off. This will induce downstream height rises. A ridge will
build over the Rckys Fri and it will gradually mv over the Plns
Sun-Mon. The Nrn extent of that ridge will get flatten as Mon
night thru Wed...probably as a wk shrtwv trof mvs E thru the Nrn
Plns. But there is mdl disagreement on location/timing.
Surface: Very wk high pres will remain over the Cntrl/Srn Plns
Fri ...but a Canadian cool front will slip into the Nrn Plns. This
front will cont S and cross the CWA Sat. Wk high pres will arrive
Sat night but depart to the E Sun as a warm front forms from Wrn
ND thru cntrl KS. As strong low pres mvs thru Srn Canada...this
warm front will move E thru the CWA Mon night. A sfc trof in the
warm sector is fcst to mv thru Tue aftn. Wk high pres should then
arrive Wed. Some of these details are a bit sketchy gvn the
uncertainty noted aloft.
Temps: near normal. Tue is looking like the warmest day of this
fcst and temps could be abv normal.
It could get pretty humid Mon-Tue as dwpts climb into the mid-upr
60s.
Rain: Drier than normal...but there will be an isolated tstm or
two here and there from time to time. The overall the chance of
rain will be low except Sun ngt into Mon...when the chance of
tstms will increase on the cool side of the warm front.
Instability and shear will be sufficient for storms to be svr.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 608 PM CDT Wed May 29 2019
VFR conditions are forecast trough the period as NW winds and
drier air moves into the area.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Beda
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1038 PM CDT Wed May 29 2019
.UPDATE...
A broken line of showers and storms continues to move eastward
across Texas and towards our area. We do have some amount of
instability available to these storms, but we also find ourselves
underneath a 700 mb thermal ridge, and divorced from more
significant upper troughing. If the line`s cold pool can sustain
low level convergence, we can continue to manage a broken line of
showers and storms, but capping and upper subsidence indicated in
Austin AMDAR soundings, as well as a decreasing moisture gradient
to the east per GOES-East, will not be favorable for line
maintenance.
All in all, continue to keep decent PoPs in place in our far
northwestern edge, but in keeping with a scenario similar to the
HRRR and other CAM guidance, kill things off pretty rapidly from
there. Nearer the coast, do increase PoPs as onshore flow should
result in the development of streamer showers towards dawn.
Later tomorrow, bring PoPs up from both ends, as the upper jet`s
right entrance region comes closer, along with better potential
for forced lift as the cold front shows up on the scene.
&&
.PREV DISCUSSION /Issued 620 PM CDT Wed May 29 2019/...
.SHORT TERM [Tonight Through Friday Night]...
Low pressure was located near the Big Bend region and high
pressure was over the FL panhandle at mid-afternoon. The flow
between these two features has allowed a ribbon of deeper moisture
to develop over the western third of the CWA on a strong onshore
flow. Isolated showers will persist near this corridor of deeper
moisture this evening, however most of SE TX will likely remain
dry through 9 PM or so. A cold front over N TX will slide south
later tonight. This feature will bring scattered showers and
thunderstorms to the area late tonight. PW values will increase to
between 1.80 and 2.00 inches but instability is not terribly
impressive with the best dynamics confined to mainly the northern
third of SE TX. SPC has outlooked the northern third of the
region, roughly north of a Brenham to Huntsville to Trinity line.
If severe weather does develop, the primary severe weather hazard
will be large hail and damaging winds.
On Thursday, the weak cold front will approach I-10 and probably
stall. Low level convergence along the boundary coupled with weak
lift provided by a weak right rear quad of a departing 75 kt jet
should allow scattered showers and storms to develop. Best rain
chances look to occur between 15-21z as PW values increase to
around 1.90 inches and mid level frontogenesis peaks. Cloud cover
and precip should suppress temperatures a bit and will shave a few
degrees from todays high temps for Thursday. Overnight low
temperatures will remain warmer than normal with cloud cover.
Upper level ridging over the western Gulf expands toward the Upper
Texas Coast on Friday. A weak upper level disturbance sliding
over the top of the ridge should generate scattered showers and
thunderstorms. Not sure if increasing subsidence from the ridge or
lift from the short wave will prevail so will go with 30/40 PoPs
for now. 500 hts build as the upper ridge expands and temperatures
will begin to warm back up. Lower 90`s will prevail over the
southern 2/3rds of the CWA with cooler temperatures to the north
closer to the track of the short wave. 43
.LONG TERM [Saturday Through Wednesday]...
Upper ridging will commence a dry period that will dominant the
extended. Southern based mid to upper level ridging with no upper
level support will provide the subsidence required to keep any
precipitation confined to the mesoscale...either early day near
coastal streamer showers or isolated showers along the sea/bay
breeze boundaries. Slight rain chances across the far northern
counties may exist on both Friday and Saturday afternoons to
account for weak shortwave disturbances passing atop the ridge
axis in the ArkLaTex region. Mostly cloudy mornings will evolve
into partially cloudy afternoons...average middle 70 minimum
temperatures with afternoons warming into the lower to middle 90s.
Overall moisture will ebb and flow to as low as 1.2 inches to
near 1.7 inches pwats under southern steering flow. Afternoon dew
points in the lower 70s with ambient lower to middle 90s will
produce near 100 F heat indices. 31
.AVIATION [00Z TAF Issuance]...
Extremely complex forecast ahead for the area. Here is a brief
sketch of what may lie ahead - I expect that tweaks, potentially
even wholesale changes may be needed in future issuances.
Overnight: a line of strong to severe storms will weaken as it
slowly drops towards Southeast Texas. Sketch out a period of VCTS
at CLL and UTS overnight as to when storms - if any - are expected
to arrive. Very conditional threat here, and there may be no
storms at all.
Tomorrow: a cold front drops into the area. Separated from the
best forcing, there is not a lot of confidence in timing or
strength. General idea tonight is that the front will push through
the northern third to half of the area fairly well this morning,
then slow as it nears IAH. It should stall out, and I end the
forecast period with things in the general vicinity of the Houston
terminals. Use PROB30s for now to highlight most likely windows at
this time.
LBX and GLS: Despite the complexity elsewhere, these TAFs are
fairly straightforward as I stall out the front before reaching
here. If the front pushes more towards the coast, more than a
simple VCTS window may be needed.
.MARINE...
Surface high pressure building down for the Southern Plains through
late week will weaken the onshore pressure gradient. Thus, winds
will be on the decline through Friday and seas will accordingly
fall an average 3 to 4 feet by Saturday. Late week minor coastal
wave run up to between 2 to 2.5 feet MLLW and weakened rip currents.
Overall high pressure across the local waters from the weekend on
through mid next week will generally maintain near 10 knot onshore
winds and sub 2 foot significant wave heights. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 74 87 72 87 71 / 50 30 30 40 20
Houston (IAH) 76 89 74 90 74 / 20 60 40 40 20
Galveston (GLS) 79 85 79 87 79 / 30 30 10 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CDT Thursday for
the following zones: Coastal waters from Freeport to
Matagorda Ship Channel TX out 20 NM...Coastal waters from
High Island to Freeport TX out 20 NM.
Small Craft Advisory until 11 PM CDT this evening for the
following zones: Waters from Freeport to Matagorda Ship
Channel TX from 20 to 60 NM...Waters from High Island to
Freeport TX from 20 to 60 NM.
SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CDT Thursday for
the following zones: Waters from Freeport to Matagorda Ship
Channel TX from 20 to 60 NM...Waters from High Island to
Freeport TX from 20 to 60 NM.
&&
$$
UPDATE...Luchs/Overpeck
SHORT TERM...43
LONG TERM...31
AVIATION...Luchs
MARINE...31
Area Forecast Discussion
National Weather Service North Platte NE
634 PM CDT Wed May 29 2019
.SHORT TERM...(This evening through Thursday night)
Issued at 321 PM CDT Wed May 29 2019
The upper low which has produced rain across the region for a few
days now is swirling slowly across SD, MN and IA. The model
consensus backed by the RAP and HRRR show lopes of energy dropping
south and setting off showers across ncntl Nebraska tonight. Most
of this additional rain will occur east of highway 83. The
forecast Thursday and Thursday night is dry. Sfc high pressure
will build south through the cntl Rockies and this places wrn and
ncntl Nebraska in a stable northwest flow. None of the models show
afternoon destabilization, despite cold air aloft.
The temperature forecast follows the guidance blend plus bias
correction. This produced lows in the 40s to around 50 tonight,
highs in the 70s to near 80 Thursday, and lows in the upper 40s to
mid 50s Thursday night. We are expecting nearly full sun Thursday
with afternoon cumulus clouds. The temperature forecast might be
optimistic. Bias correction cooled the guidance blend down a degree
or two.
.LONG TERM...(Friday through Wednesday)
Issued at 321 PM CDT Wed May 29 2019
The next best chance of rain occurs Sunday afternoon and evening.
The GFS and ECM are in fairly good agreement sending a ridge-runner
type wave across the Black Hills or the Laramie range. The activity
appears to grow upscale as it moves east into deeper moisture across
wrn Nebraska. POPs are fixed at 50 percent for this event and winds
aloft are around 30-35kts which suggests some potential for strong
or severe development. The days 4-8 severe weather outlook from SPC
suggests it is too early to predict the potential for severe
weather. Otherwise the forecast features some low chance POPs with a
wave dropping through the nrn Plains Monday and Tuesday.
The temperature forecast follows the model blend for highs in the
70s to mid 80s. There may be opportunities to mark these highs "up"
as temperatures at the h700mb level warm to around 12C by Tuesday.
The progression of warming is gradual so temperatures should rise a
few degrees each day, ultimately producing highs in the upper 80s
around 90 Monday and Tuesday as suggested by the bias corrected GFS
and MEX guidance. The uncertainty in the temperature forecast
revolves around back door cold fronts, cloud cover and moisture
return which can all have a negative impact on predicted highs.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 624 PM CDT Wed May 29 2019
VFR conditions should prevail over the next 24hours with the
lowest ceiling heights this evening and continuing to improve
overnight into Thursday morning.
&&
.HYDROLOGY...
Issued at 321 PM CDT Wed May 29 2019
It is the opinion of local officials and long time residents of the
Sandhills that the water table associated with Ogallala aquifer has
risen sufficiently to cause significant overland flooding in many
areas. For example, State highway 97 north of Mullen was reported to
have 18 inches of standing water over it Wednesday. The result of
overflow from one of the many lakes across this region. No
significant rain is expected until Sunday and this should allow
for improvement. It is uncertain how long it will take for these
flood waters to recede completely.
Minor flooding is expected on the North Platte river above
McConaughy and near bankfull conditions are expected below it. Minor
flooding is underway along the Elkhorn river above Ewing and near
bankfull conditions are occurring on the Calamus river below Virginia
Smith Dam. The Calamus reservoir is near capacity.
The Elkhorn river should remain high for several days but the
Calamus and North Platte river below McConaughy should gradually
recede. The North Platte river above McConaughy is expected to
remain high for several days.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Gomez
HYDROLOGY...CDC
Area Forecast Discussion
National Weather Service Louisville KY
917 PM EDT Wed May 29 2019
.Forecast Update...
Issued at 916 PM EDT Wed May 29 2019
Convection continues over mainly far southwestern KY this evening.
Convection over much of the WFO LMK area has subsided this evening
with the loss of heating and a relative area of higher stability
over much of the region. Convection has shown a downturn in
strength over the last hour as cold pools are now emanating eastward
from under the convection. The downward trend in strength should
continue over the next few hours as this western KY convection moves
eastward into a more stable airmass.
For the overnight period, convection over western KY is forecast to
move northeastward and back into the WFO LMK area overnight. We`ll
see rainfall move back into our western counties within the hour and
we may see some showers back in the Louisville metro region by 1100
PM tonight. While surface based instability will continue to wane,
model proximity soundings do show some elevated instability over the
region. Thus, it will not be surprising to see some thunder with
this activity later on tonight. Best chances for rainfall overnight
look to be west of a line from Bowling Green to about Frankfort or
so. Thus, have kept higher PoPs in these areas, with a lesser
chance further east and southeast. As cold front out to the west
pushes eastward tonight, convection will likely spread further
eastward into the Bluegrass region after dawn on Thursday.
Overall threat for severe weather tonight looks rather marginal.
Forecast shear profiles are expected to drop off while the low-level
jet refocuses out to the west. Marginal instability will be
present, so some storms could pose a gusty wind hazard, though the
most likely hazardous threat would be heavy rainfall and isolated
flooding issues. Will highlight these threats in the updated
Hazardous Weather Outlook product.
Have done a quick refresh of the grids and text/graphical products
are in production and will be available shortly.
Issued at 700 PM EDT Wed May 29 2019
Convective outflow boundary from morning convection had some severe
cells that developed along it. One HP supercell formed over
Christian and Muhlenberg counties and slid down the boundary
producing large hail through southern Butler, northern Logan and
into Warren county. While these storms have diminished, renewed
convective development along old reinforced outflow boundary has
developed. This activity is expected to lift northward. Short
range high resolution models suggest that it will hold together
through around sunset and then may diminish. The highest chances of
precipitation this evening would be in areas west of the Natcher
Parkway (or the western third of our forecast area).
Will continue to monitor the data and environment this evening and
make future adjustments to the overnight forecast in a few hours.
&&
.Short Term...(This evening through Thursday)
Issued at 319 PM EDT Wed May 29 2019
...Severe Threat Remains For Southern KY This Afternoon...
Convection from the first wave was never really able to get
established ahead of the outflow boundary, and has now pushed east
of the area. Focus is now on the still untapped airmass along and
south of the outflow boundary which is now across our southern KY
counties. Of particular interest is an isolated supercell that has
latched onto the boundary and will be moving into northern Logan
county soon. Large hail, downburst winds, and perhaps a tornado
threat will exist given the localized enhancement to low level SRH
offered by the boundary. Right now the overall setup is only
offering around 100 M2/S2 of effective SRH in that area, which isn`t
very favorable for tornadoes by itself. Keeping a close eye on this
storm as it approaches northern Logan County.
Otherwise, the other area of concern is southern IL/SW Indiana where
strong instability has developed in the wake of morning convection.
Some decent moisture convergence is going on in that area right now,
and if convection pops we will likely have to watch for strong to
severe storms developing in that area and moving back into our
southern IN counties this evening. Not overly confident in this
scenario but will have to monitor.
So, the actual forecast will call for isolated to widely scattered
storms for the remainder of the afternoon and evening, most likely
down along southern KY where the airmass remains untapped. There
should be a relative lull around and briefly after Midnight before
the next round of showers and storms begins to move into our SW
ahead of a disturbance moving into the lower Ohio and Wabash River
Valleys. Some of the storms could become strong early Thursday and
through the day however overall instability will be a little in
question despite a pretty decent shear profile. Cold front moves
through the area late evening, briefly ending shower and storm
chances from W to E. Lows tonight drop to the upper 60s, and highs
tomorrow reach the upper 70s and low 80s.
.Long Term...(Thursday night through Wednesday)
Issued at 257 PM EDT Wed May 29 2019
Thursday Evening - Sunday...
Lingering showers and a few storms are possible Thursday night into
Friday morning behind the cold front as the upper low moves into the
region. Isolated convection will then be possible Friday afternoon
mainly in east central KY as an upper level disturbance moves off to
the southeast. Otherwise, expect mainly dry weather Friday afternoon
through early Saturday as ridging builds in over the central U.S.
This will keep us in northwest flow behind the upper low, bringing
cooler temperatures to the area. High temperatures Friday will be in
the upper 70s to low 80s.
The next round of showers/storms are possible as early as Saturday
afternoon if a leading shortwave can spark convection. If not,
showers/storms may hold off until Sat night into Sunday as a cold
front dives south through the Ohio Valley.
Sunday Night - Wednesday...
A Canadian High will then build over the Great Lakes and slide to
our northeast at the beginning of next week, keeping us mostly dry.
We return to southwest surface flow Tuesday, bringing high
temperatures back into the low-mid 80s Tuesday and Wednesday.
&&
.Aviation...(00Z TAF Issuance)
Updated at 700 PM EDT Wed May 29 2019
Convectively induced outflow boundary resides across southwestern KY
this evening. This line is roughly from KHOP westward through KPAH.
This boundary is forecast to lift northward this evening and will
primarily affect western KY. The last few runs of the HRRR model do
lift this boundary northward this evening, but the convection in the
model weakens after sunset. Overall confidence in this is rather
low, so will keep some VCTS in KHNB/KSDF per the previous
amendments. KLEX looks to be least affected by convection this
evening. Probably will keep a few hours of VCTS in at KBWG due to
its close proximity to remnant outflow boundary.
Overnight, we may start off dry, but another wave/disturbance will
move into the region late tonight and into the pre-dawn hours of
Thursday. Overall, it appears that KHNB/KSDF/KBWG would be most
affected with this activity with KLEX being least affected due to
its eastward location away from convection though KLEX will likely
see additional showers Thursday morning as the disturbance rolls
northeastward. Winds overnight will be out of the southwest at 5-
10kts and will pick up again during the day on Thursday.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update.......MJ
Short Term...BJS
Long Term....AMS/JMB
Aviation.....MJ
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
815 PM CDT Wed May 29 2019
.UPDATE...
814 PM CDT
The going forecast message of increasing shower and thunderstorm
chances later this evening into the overnight looks good, along
with some chance of strong to possibly a few severe storms.
Confidence is low though on just how far north any stronger
storms may reach into our area, as well as the duration of the
highest storm coverage, as it may only be a few hour window. All
in all, the risk of hazardous weather is consistent with that of a
Marginal to low end Slight Risk for both severe and flooding.
Anomalously strong southwest flow aloft of 120 kt at 250 mb is
set to spread over the forecast area in the next few hours per
satellite water vapor imagery and 00Z upper air observations.
Embedded within this are a couple short waves, one approaching the
Quad Cities area and then a second stronger one over
central/southern Missouri. Broad ascent from the jet streak and
waves will encompass the area by shortly after midnight. The ILX
00Z sounding indicates over 2500 J/kg of MUCAPE, which matches the
SPC RAP mesoanalysis that also analyzes around 1000 J/kg over the
southern CWA. This instability aloft should inch upward these
next several hours. These are the ingredients in place for the
uptick of storm coverage into the CWA by early overnight.
A couple caveats are that the low-level jet strength is only of
25 kt into the southern CWA, and a fairly solid area of ongoing
convection along the surface warm/stationary front in central
Illinois might limit widespread moisture transport into the area.
This would have impacts on how widespread of thunderstorm
coverage and any flash flood threat. Nonetheless, showers with
embedded thunder are likely in most places overnight, and an
isolated to scattered severe threat exists with deep layer shear
forecast to peak around 45 kt. The main threat would be hail along
with possibly some strong winds. The recent tornado warnings near
Iowa City and Cedar Rapids west of the area are closer to the
surface low where there is some stronger near-surface flow and
where there was some late day destabilization at the surface. So
we are not anticipating that threat here, though could have some
supercell structures with a few storms given the sufficient 0-3 km
shear and helicity.
MTF
&&
.SHORT TERM...
241 PM CDT
Through Thursday night...
Thunderstorms will continue to be the focus of the forecast through
the near term. The persistent upper trough over the western U.S.
is breaking down a bit with an upper ridge remaining over the
southeast U.S. Water vapor imagery shows a shortwave trough moving
northeast across Oklahoma this afternoon and this will be the
focus for thunderstorm development to our southwest over the next
few hours and then locally this evening. At the surface, the
pattern is rather ill-defined with a weak east-west ridge to the
north and a surface low over western Iowa. A warm front is
positioned south of the CWA. Moderate instability has developed
over southwest IL and is gradually expanding northward up against
the front. Satellite suggest that the front, which may have
blended with old outflow from overnight convection, is still
moving southward based on progression/development of lower level
clouds. It seems that the instability analysis may be a little too
aggressive with the current northward extent. This, along with
the fact that there is little in the way of a triggering
mechanism, supports minimal potential for any type of convection
to develop in the CWA through late afternoon or early evening.
Getting back to the upper wave coming across Oklahoma, current convection
moving northeast across SW MO and points southwest is expected to
expand or new development may occur to its north as the trough
moves along and is aided by a cold frontal boundary extending
south from the low over Iowa. Guidance is not in great agreement
in how things play out but based on observed trends and forecast
of larger scale features, expect that thunderstorms will move in
from the southwest by mid evening and continue across the area
into the early overnight. Severe potential is a bit of a question
mark given how far south instability currently is, though it will
likely start to lift north into the evening. Still favor areas
south of I-80 or perhaps even U.S. 24 for large hail and gusty
wind threat, with little threat to the north. As far as heavy rain
potential, guidance is mixed but based on current trends and
guidance that seems to possibly have a better handle on the larger
scale, the best moisture largely peels to the south of the area
into early tonight. That said, isolated heavier rainfall is still
possible, where convection is most intense and persistent.
Most if not all activity should be exiting to the east Thursday
morning. Another upper trough crosses the area during the
afternoon evening but has much less moisture to work with than
recent systems. However, it still supports low chances for showers
and isolated thunderstorms. Highs will be in the low to mid 70s
for most areas but lakefront areas will be kept cooler. May be a
little optimistic with lower 60s at the lakefront. Shower chances
may linger in the south into early evening but should exit for the
overnight.
MDB
&&
.LONG TERM...
206 PM CDT
Friday through Wednesday...
Main forecast concerns through this period include showers and
storms with a cold front and upper level short wave on Saturday...
followed by another round of rain and storms Tuesday into Wednesday
with another upper level shortwave. Perhaps equally noteworthy is
the stretch of dry weather expected Sunday and Monday! This assumes
a vigorous upper level shortwave currently progged to pass to our
northeast stays there.
The upper flow pattern over the local area transitions to a
northwest flow with the exit of Thursday night`s upper level trough.
Models coming into better agreement on the details in bringing an
upper level shortwave across the northern plains and into our area
Saturday. Dynamics impressive enough to support thunderstorms... and
we`ll need to monitor parameters as the event draws nearer in order
to determine just how feisty those storms may become.
Fairly sprawling surface high pressure builds into the area Sunday
lasting into Monday. Temps will be a little below seasonal norms...
especially near Lake Michigan where winds will have an onshore
component both days.
Split flow developing over the mountain west mid-week next week
as the west coast upper low moves east complicates our forecast
for that time period... however current model trends suggest
perhaps a couple of different periods of rain Tuesday and
Wednesday... warranting low pops in the forecast that period for
now.
Ed F
&&
.AVIATION...
For the 00Z TAFs...
VFR conditions in place at the start of the period, with these
conditions likely persisting for much of this evening. Expect
precip chances to increase across all of the terminals close to
around the midnight time frame tonight, with VFR ceilings
spreading overhead during this time. Will see current showers and
storms across central IL likely increase in coverage as they lift
north through the evening hours. Do have confidence for at least a
couple hour window of thunder tonight, with some possibility that
this thunder lingers around slightly longer than currently
forecast. Under these showers and storms, will see vis drop to
around 3sm, with some 1-2sm vis possible in the stronger storms.
Thunder chances will lower during the overnight hours, but with
showers likely continuing into the early morning period on
Thursday. Ceilings should stay mainly VFR, though a period of MVFR
will be possible. VFR and mainly dry conditions expected on
Thursday, as additional precip development Thursday afternoon
should remain just south of the terminals. Easterly winds in place
this evening expected to become more southerly tonight, and then
southwest to west on Thursday.
Rodriguez
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
731 PM EDT Wed May 29 2019
.SHORT TERM...(This evening through Thursday)
Issued at 343 PM EDT WED MAY 29 2019
Temperatures today climbed well into the 70s, as the Lake Superior
breeze came through temperatures were quickly knocked back down into
the 60s inland to 50s near the lake. Tonight and early Thursday
morning, a cold front will cross Lake Superior and Upper Michigan,
which will switch the prevailing winds to more northerly. This will
hinder high temperatures tomorrow for most of all Upper Michigan
outside of Iron and Dickinson Counties which may sneak out a few
70s. Should the front come in slightly later than forecast, expect
temperatures to climb further into the 70s.
RAP analysis and model upper air maps show confluent flow at both
500 and 250mb which will contribute to NW flow, sunny skies, and dry
conditions. The big question for Thursday, is just how far the RH
values fall in the afternoon. Current forecast shows RH values fall
into the 40s east, and perhaps into the 20s in western and central
interior. NAM/GFS forecast soundings show mixing up to around 750-
800mb. This deeper mixing has the potential to create gusty
conditions at times with winds blowing up to 20 kts at times inland.
.LONG TERM...(Thursday night through Wednesday)
Issued at 416 PM EDT WED MAY 29 2019
A weakly negative NAO pattern with a blocking ridge centered near
the Davis Strait and associated trough over eastern Canada will
favor northwest flow through the northern Great Lakes through the
weekend. As a ridge over western gives way to lowering heights a
more zonal pattern is expected to develop next week.
Thursday night, with favorable radiational cooling conditions at
least into the evening, the forecast maintains temps toward the
lower end of guidance for inland locations. Readings into the lower
30s at favored cold spots could result in patchy/areas frost inland
central and east. Some increase in clouds expected overnight with
increasing mid-level moisture and weak forcing ahead of a shortwave
and associated sfc low moving down from southern Canada may stop
temps from falling or cause a slight rise in temps toward sunrise,
especially over the west.
Fri, a shortwave trough diving se through Ontario will drag a cold
front into the region. WAA and moisture advection ahead of the front
will bring MLCAPE values up into the 500-1000 J/Kg range for
counties along the WI border by Friday afternoon. Although the
stronger fgen/isentropic lift and higher pcpn chances remain north
of Upper Michigan into the afternoon, as the front approaches,
expect sct/isold t-storms will develop over the interior west and
spread into south central Upper Michigan by evening. Deep layer 0-
6km shear to 50 knots suggest that there could be a conditional risk
of a few strong/severe storms.
Sat-Mon, high pressure is again expected build across the area and
dominate with confluent nnw mid/upper flow. Models diverge by Sunday
as the 06z/12z GFS and majority of GEFS ensembles maintain dry
conditions under sfc high pressure and confluent flow aloft while
the 00z/12z ECMWF advertises a fairly potent shortwave spreading
showers and batch of cold air (850 mb temps lower near 0C) across
the Upper Great Lakes. All models suggest drier conditions will
prevail on Monday although the ECMWF indicates a much cooler day
than either the GFS with cold air lingering over the area from in
the wake of the stronger shrtwv on Sunday.
Mon night into Wed, As the flow becomes more zonal across the
northern CONUS, moisture/instability will move back toward the area
along with increasing shower chances with the approach of a sfc
trough from the Upper MS valley.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 731 PM EDT WED MAY 29 2019
Under a dry air mass, VFR conditions will prevail thru this fcst
period at KIWD/KCMX/KSAW. NNE winds will become gusty to 15-20kt at
KSAW Thu aftn.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 343 PM EDT WED MAY 29 2019
Lake Superior will remain below 20 knots through the weekend. There
are some indications of winds near 25 to 30 knots mid next week, but
confidence on for those winds are low. In the near term, expect a
trough to pass late this week bringing showers across the lake on
Friday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JAW
LONG TERM...JLB
AVIATION...Rolfson
MARINE...JAW
Area Forecast Discussion
National Weather Service Pueblo CO
341 PM MDT Wed May 29 2019
.SHORT TERM...(This evening through Thursday)
Issued at 340 PM MDT Wed May 29 2019
Current water vapor imagery and upper air analysis is indicating
generally weak west to southwest flow aloft across the region, as a
weak upper trough continues to dig across the Rockies this
afternoon. Cold air aloft (-18C to -20C at H5) has allowed for steep
lapse rates and scattered to numerous showers, as well as a few
thunderstorms, to develop across the higher terrain this afternoon,
with showers spreading east across the high valleys and trying to
move east across portions of the I-25 Corridor this afternoon. Snow
levels have remained relatively high (around 10,000 feet) this
afternoon, with CDOT cameras indicating snow falling across the
higher mountain passes along with wet roadways, though the Pikes
Peak cam is indicating some light accumulations at this time.
Tonight and Thursday...Weak upper trough continues to dig across the
Rockies tonight as parent upper low across the Northern High Plains
continues to slowly lift north and east through the day tomorrow.
The latest model runs continue to indicate weak upper level ridging
building across the Central and Northern Rockies, as more Eastern
Pacific energy digs across the West Coast. With that said, with loss
of heating, will see showers and storms over the higher terrain
diminishing through out the evening, with the biggest question being
where the best coverage of showers moving across the I-25 Corridor
will be, as the higher res HRRR runs have been waffling on better
coverage across COS and northern portions and PUB and southern
portions of the Corridor. At any rate, I kept scattered pops in
through the evening, with slowly clearing skies across the region
into early Thursday morning. For tomorrow, with warmer temperatures,
some 5 to 15 degrees warmer than today, and residual moisture,
should see another round of scattered afternoon showers and
thunderstorms, with greatest coverage over and near the higher
terrain. Good see a few stronger storms, with progged capes of 600-
1200 j/kg across the area, though with weak flow aloft and less
shear, would be the pop and drop variety, expect for areas along the
Raton Mesa, where models indicate the best shear supporting a
rotating storm.
.LONG TERM...(Thursday night through Wednesday)
Issued at 340 PM MDT Wed May 29 2019
Thursday evening into Friday morning...Mixed layer CAPE values of
around 1,000 to 1,200 J/kg along the southern CO border from the
Raton Mesa to the eastern border with some marginal deep shear
(approaching 30 kts) will continue to be possible during the evening
hours, which could produce a strong to marginally severe storm or
two. Elsewhere, any storms that do develop should be more of the
garden variety type. Some light snow will also possible over the
higher elevations, generally above 10,000 feet.
Friday through Wednesday...An upper level trough is expected to set
up over the western CONUS, which should bring some mid to upper
level ridging over CO starting Friday afternoon. As a result,
westerly flow aloft is expected Friday afternoon, becoming more
southwesterly through the weekend and early parts of next week as
the trough slowly digs southward into the far southwest CONUS. The
trough and ridge are expected to then be relatively stationary
through the first half of the week. This pattern will promote
diurnal showers and thunderstorms each day, especially over the
mountains and across the plains. Sunday appears to be another day
with a potential for stronger storms to develop over the far eastern
plains as stronger southerly winds at the surface should bring
additional moisture to that area. Models are also indicating that
CAPE values could approach 2,000 J/kg with moderate deep shear
values (greater than 40 kts) during the afternoon and evening hours
somewhere near the CO - KS border. The GFS has the higher CAPE and
shear values located farther west into CO, while the ECMWF has them
located in western KS. Models suggest that this trough will finally
progress eastward by mid week, but it is too uncertain at this time
to know exactly when or how quickly it will move. Temperatures
should gradually warm through Monday to near 90 for the plains and
mid 70s in the high valleys before moderating Tuesday and Wednesday.
With the warmer temperatures and diurnal precipitation chances, the
flood potential over the burn scars will likely need to be monitored
during the weekend and early part of next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 340 PM MDT Wed May 29 2019
Mainly VFR cigs expected at COS and PUB through early tomorrow
morning, with showers and thunderstorms over the higher terrain west
of the terminals this afternoon and evening. A few showers look to
move off the higher terrain and across the terminals late this
afternoon and early evening, bringing the potential for brief MVFR
cigs, especially at COS. Northerly winds 10-15kt through the day
look to become light and variable overnight, and then become
generally light upslope through mid morning Thursday. Another round
of afternoon showers and storms can be expected tomorrow afternoon,
with the best coverage over and near the higher terrain.
VFR conditions expected at ALS through the period, with scattered
showers and storms over the higher terrain this afternoon and
evening, possibly moving across the terminal late in the afternoon
or early evening. Breezy south to southwest winds 10-20kt through
the afternoon, becoming light and variable overnight. Another round
of afternoon showers and storms can be expected tomorrow afternoon,
with the best coverage over and near the higher terrain.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MW
LONG TERM...CARLBERG
AVIATION...MW
Area Forecast Discussion
National Weather Service Shreveport LA
732 PM CDT Wed May 29 2019
.UPDATE...
To headline new Tornado Watch 296 until 06Z/1 a.m. & AVIATION
&&
.SHORT TERM...
The SPC has bridged the old Tornado watch 293 into more of AR and
issued 296 keeping things covered for much of our area now
through the evening hours. Thunderstorms are lining up from near
Tyler to Mount Pleasant and nearing DeQueen. A lot of discrete
smalls coming together now is hopefully good news along with the
setting sun in an hour. /24/
&&
.AVIATION...
For the ArkLaTex, afternoon convection has kept just out of range,
but will overspread KTYR/KTXK soon. Beyond that, certainty
depends on cool pool of rain cooled air to help what is a very
weak cool front approaching. Southerly flow will keep TS active
overnight with the SVR threat diminishing after sunset. Overnight
activity will be tempoed for additional terminals upon approach
of the SQ line. SW winds at daybreak will veer to W/NW into the
afternoon as front eases over our area. Additional convection is
possible, but will be much weaker by comparison. /24/
&&
.PREV DISCUSSION... /issued 410 PM CDT Wed May 29 2019/
SHORT TERM.../Tonight through Thursday night/
Cloudy and cooler in the NW with mid to upper 70s in rainy areas,
but most of our area is in the mid to upper 80s with 90 at
Natchitoches at 90 now the hot spot. The SE surface winds and S/SW
aloft are presenting the tornado threat in our West with the cap
barely holding over SHV. However, the models indicating a slow
push into the heart of the area this evening and still with some
QLCS potential, but even the HRRR is a little less bullish now
compared to a couple of hours ago. The current tornado watch goes
until 8 pm, so depending on evolution of convection we could not
only wide down the tornado threat, but perhaps even the flooding
threat for the overnight. Stay tuned. We added a couple of
counties to the Tornado watch and pushed up the flash flood watch
start time.
A weak shift to NW will unfold mid to late morning helping to
further the pops and weather across much of the cwa. Thursday will
be cooler by comparison, but not less much muggy at least to
start. Patchy fog may also become a problem for wet spots. Highs
tomorrow will slowly warm as the low clouds early will be
stubborn, but low to mid 80s may work out. Overnight lows will
range in the 60s for early risers on Friday. /24/
LONG TERM.../Friday through Tuesday Night/
Expect slightly drier and cooler air to hang on through Friday and
Friday night in the Four State Region, although an isolated shower
or storm still cannot be ruled out in southern/southwestern zones
near where the previous frontal boundary stalls and washes out.
Thereafter, expect heat to build as an upper level ridge builds
towards TX and westerly flow vectors aloft (over our region)
institute a hotter regime. There is some opportunity for a marginal
"northwest flow" setup to bring the remnant edges of thunderstorm
complexes into our northwest and western zones Saturday and Saturday
night, but the better chance (but still only roughly 30 percent
chance) of daytime PoPs will hold off until Sunday into early next
week as deeper southerly flow brings in better moisture profiles to
fuel afternoon convection.
At this point we are not anticipating enough clouds and rain around
through the long term period to significantly blunt the warming
trend associated with the building upper ridge in the vicinity.
Ergo, we expect highs in the low to middle 90s to be rather
ubiquitous come late this weekend and through early next week.
Fortunately, the mini, early heat wave should probably not have
major legs as model consensus is decent another front should sag in
from the north later next week. /50/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 85 66 88 / 30 40 10 10
MLU 71 87 67 89 / 10 50 10 10
DEQ 63 83 60 86 / 80 10 10 10
TXK 67 83 62 85 / 80 50 10 10
ELD 69 85 63 88 / 50 40 10 10
TYR 69 83 65 85 / 80 50 10 20
GGG 72 84 65 87 / 50 50 10 10
LFK 73 87 69 89 / 30 50 20 30
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Flash Flood Watch until 7 AM CDT Thursday for ARZ050-051-059>061-
070.
LA...None.
OK...Flash Flood Watch until 7 AM CDT Thursday for OKZ077.
TX...Flash Flood Watch until 7 AM CDT Thursday for TXZ096-097-108>112-
124-125.
&&
$$
24/50