Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/01/19
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
941 PM CDT Tue Apr 30 2019
.UPDATE...
The main update to the forecast is to trim back PoPs during the
overnight hours. Other than a very low chance across the Edwards
Plateau and Hill Country have removed all rain chances through about
1 am across the area. The storm near Ozona from earlier in the
evening has died out after producing 3 inch hail there. The only
thing on radar tonight are the bats north of Uvalde and near Bracken.
A few runs of the HRRR this evening did show a rogue supercell
forming across the Mexican mountains before dying as it approached
the border. There is no signal of any significant development per
the GOES-16 IR channels so these runs were disregarded.
For the second half of the night high resolution models do still show
some streamer showers across the area towards morning so have
blanketed the area with 20 PoPs for the light rain chances.
Looking ahead towards tomorrow the 00z runs of the NMM and ARW high
resolution models are in through tomorrow evening and they, along
with the 18z Texas Tech WRF, show the majority of the strong
thunderstorm activity staying to the north of South Central Texas
with outflows and some isolated showers and storms moving through
mid-afternoon into the early overnight hours tomorrow. These are
just the early model trends, and no adjustments to the ongoing
forecast were made at this time. A full forecast package with a look
at all the High Resolution and Synoptic Models will be issued during
the early morning hours Wednesday, with the next SPC Day One Outlook
expected around 1 AM local time.
&&
.PREV DISCUSSION... /ISSUED 639 PM CDT Tue Apr 30 2019/
AVIATION...
SHRA along and just west of I-35 and have kept VCSH at those sites
going through early evening with VFR skies. MVFR CIGs return later
this evening into overnight. There is a possibility of IFR CIGs early
in the morning, however, it will be brief as lower level flow keeps
the airmass mixed somewhat and have kept mention out. CIGs lift to
low end VFR around midday on Wednesday. Still expect SHRA/TSRA to
develop over West to North Central Texas and drift southeast into
Central Texas and the Hill Country during the afternoon into evening.
Have maintained VCTS at KAUS and VCSH at KSAT/KSSF. Southeasterly
winds of 10 to 20 KTs prevail with occasional gusts to 25 KTs.
Downdraft wind gusts up to 50 KTs are possible in and near TSRA.
PREV DISCUSSION... /ISSUED 244 PM CDT Tue Apr 30 2019/
SHORT TERM (Tonight through Wednesday Night)...
Isolated streamer showers continue beneath the cap this afternoon.
Aircraft sounding out of AUS do indicate some slight weakening of the
inversion around 750-700mb, but not completely eroded. Thus, for the
most part this evening we expect the deeper and more organized
convection to remain north of the CWA, where cap is eroded and in
closer proximity to better forcing. Although, we can`t rule out
isolated thunderstorms across the far northern CWA.
The next shortwave embedded in the southwest flow aloft will move
across portions of the southern Edwards Plateau and into West Central
Texas overnight and Wednesday morning. Most of the hi resolution
model guidance agrees the bulk of the convection will develop through
the morning and into early afternoon just to the north of the CWA.
Convective outflow boundaries may then move south into portions of
the northern CWA late afternoon. We do think the cap will be eroded
or weak enough to sustain convective development during peak heating
into portions of the northern CWA late Wednesday afternoon and early
evening, including most of the eastern Hill Country and Austin metro,
and this is where the higher PoPs are favored. Model forecast
soundings disagree with strength of cap across the southern half of
the CWA. The ARW indicates a complex of storms moving southeast to
the I-10 corridor while the NAM Nest, NMM, and Texas Tech WRF
weakening and dissipating the convection Wednesday evening just south
of Austin as the cap holds.
Where the cap does erode, there will be the potential for severe
storms given MLCAPE values near 3000 J/kg and deep layer shear values
around 40 kts. Can`t rule out some very large hail across the
northwest Hill Country and southern Edwards Plateau, where mid level
lapse rate are forecast to be an impressive 8-9 degC/km. In
addition, some pockets of 1-2" of rainfall are possible across the
far northern CWA.
LONG TERM (Thursday through Tuesday)...
There are still model differences for the forecast on Thursday, with
the ECMWF and Canadian developing convection in the afternoon across
the Hill Country, closer to a weak frontal boundary, while the GFS
and NAM12 maintain the convection and weak boundary north of the
area. PoPs are trending higher for Thursday night through Friday
night with the next mid level shortwave. It`s too early to pinpoint
timing and favored locations this far out, and there are some
indication in the models of convective feedback. Nevertheless,
showers and storms are likely at some point during this time frame.
A few stronger storms will be possible in addition to some pockets
of heavy rainfall, given anomalously high precipitable water values
pooled around 1.5-1.8" over potions of the region. The forecast
trends drier Saturday into Sunday.
The next shortwave, ahead of a deeper closed low digging through
southern California, is forecast to impact South Central Texas Monday
with another chance of showers and storms.
7 day rainfall totals over portions of the region could end up being
2-4" with some isolated pockets in excess of 6".
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 71 81 70 84 69 / 20 70 60 40 40
Austin Bergstrom Intl Airport 72 81 69 84 68 / 20 60 60 40 40
New Braunfels Muni Airport 72 81 69 84 68 / 20 50 50 20 40
Burnet Muni Airport 70 77 67 81 66 / 20 80 60 40 40
Del Rio Intl Airport 73 88 69 87 69 / 20 30 20 20 40
Georgetown Muni Airport 71 79 69 83 67 / 20 80 60 40 40
Hondo Muni Airport 72 87 69 88 69 / 20 40 30 20 40
San Marcos Muni Airport 71 81 69 85 67 / 20 60 60 20 40
La Grange - Fayette Regional 73 86 72 86 70 / 20 50 40 20 40
San Antonio Intl Airport 73 83 70 86 69 / 20 50 50 20 40
Stinson Muni Airport 73 84 71 86 70 / 20 40 50 20 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Aviation...04
Short-Term/Long-Term...Treadway
Area Forecast Discussion
National Weather Service Fort Worth TX
946 PM CDT Tue Apr 30 2019
.UPDATE...
With the loss of daytime heating and the main forcing mechanism
now pulling far away from the region, the warm advection
"streamer" convection has just about come to an end. The primary
concern through the overnight hours will be the complex of storms
in Oklahoma continuing to sag southeastward as it follows the
march of its expanding cold pool. This should put the best
chances of rain along the Red River and into the northeast zones.
While severe weather can`t be ruled out, the main threat will be
heavy rainfall - and the flash flood watch looks like a good call.
Have lowered PoPs along and south of I-20 but kept them from 60
to 80 percent in the northern and northeastern zones. We will
likely expire the remaining counties from the tornado watch
shortly.
Another convectively active day is expected Wednesday and a
cursory look at the latest guidance suggests that forecast is
still on track.
TR.92
&&
.AVIATION... /Issued 705 PM CDT Tue Apr 30 2019/
Severe convection in the northern and northwestern part of the
TRACON will continue to move northward. Will show VCTS in
Metroplex TAFs, but only show TEMPOs for additional TSRA on
station at KAFW and KFTW for the remaining storms near Granbury
through 3z. Otherwise with the loss of heating and forcing
pulling northward we expect these streaming storms to end and the
remainder of the evening to be quiet. However, we will keep an eye
on the potential for a line of storms that may develop along the
Red River and build south through the night. This potential looks
too low to mention in TAFs at this time.
MVFR CIGs will move into the area from the south after midnight
and should prevail through tomorrow morning. Another round of
forcing will move towards us after daybreak and convection should
develop over the region. Have indicated VCTS as all sites from mid
morning to afternoon, as it`s too difficult to pick a window for
exact timing right now...except at Waco where the 16-20z period
may have the highest chances.
South winds will prevail near 15kt except in and near convection.
TR.92
&&
.DISCUSSION... /Issued 312 PM CDT Tue Apr 30 2019/
The forecast across North and Central Texas can be summed up in
one word: challenging. That being said, things are becoming a bit
more clear with regards to the potential for multiple rounds of
strong to severe thunderstorms as well as the threat for flooding
(both flash flooding and main-stem river). Let`s get to it....
Surface and satellite analysis this afternoon revealed that
pockets of diabatic heating were continuing as strong southerly
flow continued to pump northward. This moisture was flowing
beneath a remnant capping inversion across the area. This capping
has been efficient at keeping most of the convection in check, but
as pockets of heating and additional moisture lifts northward, I
expect this to change. Our 18 UTC weather balloon data in tandem
with WSR-88D VWP indicate decent 0-1 km shear with RAP analyzed
CAPE values in excess of 2500 J/kg. 0-6 km shear values near 35
knots and all these factors combined will support supercellular
structures capable of all severe hazards. HRRR guidance remains
aggressive with the overall coverage of rotating storms. While the
idea of showers morphing into strong to severe thunderstorms
appears to be likely, I still feel the coverage of intense
convection advertised by HRRR and NSSL WRF guidance is overdone
given the remnant capping. The most intense activity should be
more isolated to scattered in nature and convection that can
breach this cap will almost certainly become severe with large
hail and damaging winds the probable hazards. The tornado threat
does exist, especially near a diffuse frontal boundary/differential
heating zone across the Big Country. The one fly-in-the-ointment
with regards to a substantial tornado threat will be some subtle
weakness in the wind field at 700mb. It`s yet to be seen whether
or not this will make or break the event, but something noteworthy
to consider. It is hard to ignore the strong upward updraft
accelerations (due to large CAPE values), increasing 850mb winds
(flow nearing 40-50 knots) and backed surface flow (especially in
the vicinity of the boundary), however. Given these factors and
after coordination with the SPC, it was determined that a Tornado
Watch was the more appropriate product for a good portion of North
Texas and parts of Central Texas...even though large hail and
damaging winds will be the more likely/numerous hazards.
Convection across Oklahoma may slowly evolve into a backward
propagating MCS in response to that strengthening low level wind
field mentioned earlier. It should be mentioned that if
convection to the north remains a bit more isolated/discrete in
nature, back building may be very difficult and could diminish the
overnight heavy rain threat along the Red River. However, several
runs of the NAM NEST and now the latest TTU WRF both depict a
backbuilding MCS/slow moving thunderstorm cluster and given the
very moist regime, the potential for thunderstorm cell training,
along with coordination from the Weather Prediction Center, I
feel confident in going with a Flash Flood Watch for locations
north of the I-20 corridor. Even more so, additional periods of
rainfall will likely result in nearly instantaneous runoff during
the middle to late portion of the week. Spatial and temporal
alterations to the current Flash Flood Watch will likely be
needed.
The MCS should move eastward into the Ark-La-Tex on Wednesday
morning, just in time for another area of convection to develop to
the southwest across the Big Country. There should be some lift
from an approaching shortwave trough and perhaps some mesoscale
ascent should any outflow boundary be shunted southward. South of
this boundary, the airmass should be pretty pristine with 70
degree dewpoints, high instability and sufficient wind shear for
severe weather. North of this area, the airmass be a bit more
contaminated from previous days convection...but if this does not
occur, more of North and Central Texas will be under the threat
for severe weather. On Wednesday, renewed convection appears most
likely across the Big Country and most model guidance (hi-res and
non-convective allowing models) have been pretty bullish on
QPF over the last several days. It seems probable that some
convective complex will develop and march eastward through the day
on Wednesday. I`ve bumped up PoPs to around 80% with a mention of
heavy rainfall for a good portion of the area. Flooding and Flash
Flooding will be likely for areas that experience rain today
(Tuesday) and extension of the current Flash Flood Watch may be
needed southward.
The forecast becomes increasingly challenging Thursday and even
into the weekend as large scale ascent is difficult to ascertain
in the model guidance. We will be quite moist with dewpoints
likely remaining in the upper 60s to near 70 degrees. Frontolysis
will be ongoing as a diffuse boundary slides southward through
the area. At this time, it appears that it will near a Bonham to
D/FW to Lampasas line and perhaps this will be a focus for what
could be diurnal convection before it loses all of its
baroclinicity. The airmass east of this area will remain very rich
moisture wise (forecast profiles are moist adiabatic) which will
support very warm rain processes. I`ll keep PoPs in the 50 to 60
percent range near and east of I-35 where heavy rain will be
possible. Main stem river flooding seems to be a good bet with
numerous minor and a handful of moderate river flood stages
probable.
The active weather pattern will likely continue beyond the weekend
as no real push of dry air is forecast. Any additional rainfall
for the weekend and beyond will present problems for urbanized
flooding and main-stem river flooding.
Bain
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 70 78 66 77 66 / 40 80 60 50 30
Waco 70 77 67 81 65 / 20 80 60 60 30
Paris 68 78 65 75 64 / 70 80 70 60 40
Denton 70 79 64 78 64 / 60 80 50 50 30
McKinney 69 78 64 76 64 / 60 80 60 60 40
Dallas 71 78 67 77 66 / 30 80 60 60 40
Terrell 70 78 67 76 65 / 30 80 70 60 40
Corsicana 71 78 68 76 66 / 20 80 70 60 30
Temple 70 77 68 83 65 / 20 80 60 60 40
Mineral Wells 68 77 64 82 63 / 30 80 30 40 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Thursday morning for TXZ091>095-
101>107-116>123.
&&
$$
92
Area Forecast Discussion
National Weather Service Goodland KS
820 PM MDT Tue Apr 30 2019
.UPDATE...
Issued at 820 PM MDT Tue Apr 30 2019
Widespread fog expected for much of the area overnight. Dense fog
is being advertised by a host of short term models beginning as
soon as the next hour and continuing through about 14z Wednesday.
Forecast updated for this and only thing to monitor now is when
sites begin dropping below 1/2 mile for hoisting the dense fog
advisory. With saturated airmass and widespread fog am not
expecting mins to drop below freezing so at this point threat of
frost does not appear to exist.
Could have some drizzle with the fog as well so have included that
in the forecast.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 345 PM MDT Tue Apr 30 2019
Through this Evening: A lee cyclone will deepen in eastern
Colorado this afternoon as a shortwave lifts northeast from south-
central CO toward the CO/KS/NE border. Modest low-level moisture
(H85 dewpoints 6-10C) will advect northward from northeast NM and
the TX Panhandle into southeast CO and southwest KS this afternoon
as southerly flow strengthens on the eastern periphery of the lee
cyclone -- aiding in marginal diurnal destabilization along/west
of the CO/KS border. Expect isold/sct convection to develop along
an evolving dryline in southeast CO between 20-22Z as the
aforementioned shortwave approaches, with convection tracking east
toward the KS border during the late afternoon. An isolated
severe threat may well be present in association with convection
in southeast CO between 21-00Z, however, surface based updrafts
will encounter an increasingly hostile thermodynamic environment
with eastern extent (particularly east of the CO/KS border). With
the above in mind, expect the relative best potential for isold
severe weather to remain south of Cheyenne county CO and SW-SSW of
Greeley county KS, or along/south of Hwy 50 and along/west of Hwy
27.
Tonight: With dewpoint depressions already as low as 3-8F and a
light E-ESE breeze, fog will be possible overnight, though it is
difficult to determine whether there will be fog, low stratus, or
both. At the very least, there is a potential for dense fog
across the Tri-State area -- particularly in the 06-14Z time
frame.
Wed-Wed Night: Another shortwave, currently in northern NV and
southern ID, will track east across the Rockies into the Northern
Plains in this period. Another lee cyclone will develop in advance
of the aforementioned wave Wed morning, progressing southeast
through southeast CO (during the afternoon) into OK (during the
evening). Convection is anticipated to develop on the northern
periphery of the lee cyclone as the shortwave crosses the Rockies
during the afternoon, with convection progressing ESE-SE across
the area during the late afternoon and evening. At this time, the
relative best potential for severe weather is expected to be
south of I-70 -- where the leading edge of convection will best
overlap with the warm sector. Expect lows Thu morning ranging from
the upper 20s to upper 30s, coldest north and west of Goodland
where skies are more likely to clear and winds are more likely to
weaken prior to sunrise. A Frost Advisory may ultimately be needed
across portions of the Tri-State area Thu morning.
.LONG TERM...(Thursday through Tuesday)
Issued at 119 PM MDT Tue Apr 30 2019
Relatively cold temperatures are expected Thursday morning with some
portions of the Tri-State area approaching or below freezing for a
few hours early in the morning. Widespread frost will be possible
along and west of a line from Cheyenne Wells, Colorado to Goodland,
Kansas to McCook, Nebraska. Areas of frost will also be possible as
far east of US Hwy 83 in northwest Kansas and southwest Nebraska.
Rain showers are expected across the Central High Plains Thursday
evening through early Friday morning, and an isolated rumble of
thunder or two cannot be ruled out in addition to moderate rainfall.
Total rainfall amounts could be over a quarter of an inch during
that time period.
After Thursday, a warming trend is expected for the Tri-State area
as high temperatures return to the 70s Friday and onward through the
end of the forecast period. Similarly, low temperatures will warm
back up into the 40s across the forecast area.
Showers and thunderstorms will be possible Saturday afternoon
through early Sunday morning across the Tri-State area with chances
moving from west to east through that time period. Showers and
thunderstorms will again be possible Sunday evening through early
Monday morning. Showers and thunderstorms will again be possible
Monday afternoon through late Monday morning. No severe weather is
expected at this time with this storms, but that could change with
future forecasts. Outside of showers and thunderstorms, partly
cloudy skies are expected to prevail for most of the Tri-State area
Thursday through Tuesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 450 PM MDT Tue Apr 30 2019
For KGLD and KMCK, sub vfr cigs and vis expected from taf issuance
through at least 21z and maybe a bit longer as widespread stratus
and fog cover the area. Winds generally from the northeast to
southeast at speeds 10kts or less. Could very well have drizzle at
times of lowest visibility.
KGLD could see thunderstorms near/over the terminal late tomorrow
afternoon as a weather disturbance approaches from the west.
Latest HRRR suggests thunderstorms at the terminal from 21z
through the rest of the period while NAM model has them arriving
just after 00z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...VINCENT
LONG TERM...PATTON
AVIATION...99
Area Forecast Discussion
National Weather Service Northern Indiana
810 PM EDT Tue Apr 30 2019
.SYNOPSIS...
Issued at 805 PM EDT Tue Apr 30 2019
Periods of showers with some embedded thunderstorms will affect
the region tonight into Wednesday morning. The greatest coverage
and heaviest rainfall is expected across northwest Indiana into
southwest Lower Michigan. Any moderate or heavy rainfall tonight
combined with saturated ground from recent rainfall may lead so
some flooding issues across these locations. Scattered showers and
storms are expected again Wednesday afternoon through Thursday
afternoon before a cold front sweeps across the area Thursday
night. Mild conditions are expected on Wednesday with highs
ranging from the upper 50s across southwest Lower Michigan to the
mid 70s across northwest Ohio into east central Indiana.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 345 PM EDT Tue Apr 30 2019
Hydrology concerns will continue to be the primary impact of the
short term.
Round of rain generally brought a half inch of rain to portions
of northern Indiana this morning, with a localized heavier
corridor of 1+ inch based on radar estimates along/just south of
Route 24 corridor. The forcing responsible for this rain is
beginning to lift northward across southern Lower Michigan this
afternoon as low level warm front creeps northward.
Sfc warm front remains suppressed well south of the area
across the Ohio Valley. This front is expected to reach far
southern portions of the forecast during the early overnight
and lift across remainder of the area overnight into early
Wednesday morning. Regional radar mosaic does indicate presence
of a couple of mesoscale convective vortices across eastern
Iowa/northeast Missouri which will also aid in northward
progression of the warm front later this evening into the
overnight hours. RUC mesoanalysis does indicate pocket of
respectable MUCAPE on order of 2000 J/kg beginning to nose into
central Illinois, which should advect across northwest Indiana
this evening as low level flow/moisture transport strengthens.
This axis of strongest moisture transport should also coincide
with 1.5 inch PWATS. The greatest duration of low level moisture
convergence with northward retreating warm front should also exist
across northwest portions of the area. These locations have
received as much as 1-1.5 inches of rain the past 36 hours, and
the potential of another 1-2 inches tonight (locally higher
possible). Given the above factors will issue a flash flood watch
for most of northwest Indiana and far southwest Lower Michigan for
tonight through noon Wednesday.
Given aforementioned MUCAPE axis lifting into the area at the
leading edge of somewhat respectable mid level lapse rates, can also
not discount isolated hail potential at least for a brief time
this evening across the southwest.
Temps will exhibit a non-typical diurnal curve tonight with some
temp drops this evening and then rising overnight as warm front
lifts to the north.
Rain and embedded storms will likely be ongoing to begin the day
Wednesday. An upper wave passing across the Great Lakes will
likely take boundary back southward across NW Indiana and SW Lower
Michigan during the late morning/early afternoon, and this
boundary should slowly sag south/southeast during the day,
possibly stalling across central portions of the area. The big
question for severe potential Wednesday will be extent of
afternoon destabilization, and timing of better forcing
mechanisms. There may be a lull in stronger forcing Wednesday
afternoon, but proximity to broad right entrance region of upper
jet and possibility of weaker sheared vorticity maximum moving
into the region should provide best chance of storms to NE
Indiana/NW Ohio during the afternoon. Deep layer shear should drop
off slightly in the afternoon, but remain in the 30-45 knot
range. Mid level lapse rates also not overly impressive for
Wednesday, but this will be partially offset by warmer low level
profiles and sfc based instability. Will keep messaging going of
conditional severe threat Wednesday given forcing/instability
questions/uncertainty.
&&
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 345 PM EDT Tue Apr 30 2019
A lull in greater rain chances/rainfall rates is expected Wednesday
night into Thursday morning, but mid/large scale support should
increase again Thursday afternoon with additional scattered
showers and storms expected. Front should finally clear the area
Thursday night as this stronger forcing pushes through. River
flooding issues will likely extend through the weekend however.
After milder conditions midweek, temps closer to seasonable levels
are expected for Friday into the weekend behind this front. Medium
range models continue to indicate elevated front far enough to the
north across southeast portions of the area for additional rain
chances on Saturday, but Sunday should feature dry conditions
area-wide. A larger scale upper trough is expected to work across
south central Canada late Sunday into Monday dragging another cold
front across the region on Monday. Moisture availability should
be more limited by this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 800 PM EDT Tue Apr 30 2019
Upstream continues to focus more episodes of convection to stream
from Ozarks into northern Indiana with primary focus over
northwest Indiana/KSBN overnight. Attention on east central
Missouri mesoscale convective vorticy, along with trailing line of
convection/outflow from earlier evening convection, to maintain
sufficient TSRA probability for inclusion 01-05 UTC, along with
IFR conditions due to ceiling and reduced visibilities in storms.
Timing of next episode of convection into KSBN less certain, but
should arrive mid/late morning per latest RAP.
Lesser convection in vicinity of KFWA with focus remaining west
through north of airfield overnight. Aforementioned outflow may be
focus for additional showers through early tonight. Thereafter,
VCSH should cover for large period late tonight into Wednesday
afternoon. Provided medium confidence tempo period mid/late
afternoon TSRA mention as low pressure lifts into Michigan
thumb/southeast Ontario, shifting frontal boundary eastward.
Both sites to be affected by LLWS with arrival of ramped south-
southwest low level jet above backed surface flow
overnight/Wednesday morning.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Flash Flood Watch through Wednesday morning for INZ003>005-
012>015-020.
MI...Flash Flood Watch through Wednesday morning for MIZ077-078.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Marsili/Murphy
SHORT TERM...Marsili
LONG TERM...Marsili
AVIATION...Murphy
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Area Forecast Discussion
National Weather Service Morristown TN
849 PM EDT Tue Apr 30 2019
.DISCUSSION...
We remain in a -PNA pattern with longwave troughing across the
western half of the country and ridging over the Eastern CONUS. A
shortwave trough ejecting out of the base of the longwave is
assisting with deep convective development across the Southern
and Central Plains this evening, but strong mid-level ridging and
surface high pressure are keeping us dry.
High pressure to the east will result in low-level southwest flow
and an increase in boundary layer moisture on Wednesday. While
instability will be on the increase during the afternoon, there
will be limited lift as shortwave energy remains to our west. In
addition, mid-level ridging remains strong through the day with
RAP and NAM forecast soundings indicating very dry air between 700
and 500 mb which will hinder deep convective updrafts. For these
reasons, expect any convection to be limited and primarily across
the higher elevations of Southeast Tennessee where differential
heating along the terrain may enhance convergence and provide a
source for increased mesoscale lift. With this in mind, believe
CAMs are on track with general location and timing of convection
on Wednesday afternoon but are overdoing coverage and PoPs. With
low and mid- level heights nearly identical to today, expect
temperatures to be very similar with max temperatures in the mid
80s for most locations. The main limiting factor would be cloud
cover, and for the most part, expect a mostly clear sky with
cirrus similar to what was observed today which guidance appears
to be handling for tomorrow.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 65 86 65 84 / 0 20 20 20
Knoxville McGhee Tyson Airport, TN 65 85 65 84 / 0 10 10 20
Oak Ridge, TN 64 85 65 84 / 0 10 20 20
Tri Cities Airport, TN 59 85 61 83 / 0 10 10 20
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&
$$
JB
Area Forecast Discussion
National Weather Service Springfield MO
624 PM CDT Tue Apr 30 2019
.SHORT TERM...(This evening through Wednesday)
Issued at 305 PM CDT Tue Apr 30 2019
Rather active pattern setting up across the area at mid afternoon.
Several supercells have initiated over NE OK and have moved into
the area. The RUC is indicating that instability as well as the h8
winds will continue to increase from late this afternoon into this
evening. With 0-6km bulk shear values around 50 kts at this
time...all modes of severe weather will be possible.
Surface front is currently situated from about Ft. Scott KS to
Rolla. The warm front will lift northward overnight as a surface
wave moves up the front...however...the cold front will remain
anchored over southeast Kansas as the wave moves up the front.
This will create a heavy rain scenario over southeast Kansas and
western Missouri as cells will continue to train along the front.
As the night progresses...models are hinting at the supercells
eventually evolving into a more linear mode of convection during
the overnight hours. This will increase the damaging wind and
QLCS tornado threat as well. As the line moves through...it should
stabilize the atmosphere into the morning but with the heating of
the day...could see another round of severe weather developing
tomorrow afternoon.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 305 PM CDT Tue Apr 30 2019
As the main upper level wave begins to eject into the Plains on
Thursday...the surface front will begin to make some eastward
progress. The front should push through the region Thursday night
into Friday. However...it may be Saturday morning before the rain
finally pushes completely out of the area.
We then have about a 24-hr break before the pattern repeats itself
once again. A surface front moves southward into the region on
Sunday...stalls...and meanders across the region through the
remainder of the forecast period. An upper low digs into the
longwave trough over southern California and puts us back into
southwest flow.
Temperatures for the most part will hold fairly steady with highs
in the 70s and lows in the 50s. Day-to-day variations will be
dependent upon cloud cover and rainfall.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 612 PM CDT Tue Apr 30 2019
Convection continuing across the forecast area at this time. Most
areas outside of the convection are either VFR or MVFR with MVFR
to IFR conditions within the convection. The exception to this is
over west central Missouri and extreme southeast Kansas where most
areas are MVFR to IFR.
The low level jet will increase over night keeping winds up and
occasionally especially on the Ozark Plateau. Could also see some
LLWS between 03-09z across the area. Periods of convective
activity are expected through the forecast area.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Flash Flood Watch through Thursday morning for MOZ055>058-
066>071-077>083-088>098-101>106.
KS...Flash Flood Watch through Thursday morning for KSZ073-097-101.
&&
$$
SHORT TERM...Gaede
LONG TERM...Gaede
AVIATION...Gaede
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php
Area Forecast Discussion
National Weather Service Tulsa OK
900 PM CDT Tue Apr 30 2019
...UPDATE...
.DISCUSSION...
Updated sent earlier to remove several counties
from the tornado watch as cold pool surge undercuts
the ongoing convection. Have already seen widespread
2 to 4 inches of rain along the I-44 corridor, and
the heavy rainfall threat will eventually shift farther
east and southeast overnight. Recent HRRR and NSSL
output suggests that ongoing convection across south
central OK could eventually develop into bow echo/squall
line, pushing into southeast OK/western AR over the
next several hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 63 79 63 76 / 90 40 50 50
FSM 66 80 65 79 / 90 60 60 60
MLC 65 78 64 79 / 90 60 60 50
BVO 59 78 59 72 / 90 40 60 30
FYV 64 77 62 76 / 90 60 50 60
BYV 63 79 62 76 / 90 60 50 60
MKO 64 79 63 77 / 90 50 50 50
MIO 63 78 61 73 / 90 50 60 50
F10 65 78 63 78 / 90 50 50 50
HHW 66 79 65 78 / 90 60 70 60
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Flash Flood Watch until 7 AM CDT Wednesday for OKZ049-053>076.
AR...Flash Flood Watch until 7 AM CDT Wednesday for ARZ001-002-010-
011-019-020-029.
&&
$$
SHORT TERM...18