Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/15/17
Area Forecast Discussion
National Weather Service La Crosse WI
700 PM CDT Wed Jun 14 2017
.SHORT TERM...(This evening through Thursday)
Issued at 255 PM CDT Wed Jun 14 2017
At 2 PM, a short wave trough was producing showers and storms
across western Wisconsin. These storms were producing wind speeds
anywhere from 40 to 75 mph. The strongest wind gust was at the
Reedsburg AWOS. These storms are quickly exiting the area and the
HRRR is showing little redevelopment in the wake of this system.
As a result, we were able to cancel our portion of Severe
Thunderstorm Watch 328 early.
On Thursday afternoon, a mid-level speed max will move east across
the area. With 0-1 km mixed layer CAPES climbing up into the 1 to
2K range, expect isolated to scattered showers and thunderstorms
to develop mainly along and south of the Interstate 90 corridor.
With 0-3 km shear generally less than 30 knots, not anticipating
any severe weather from these storms.
.LONG TERM...(Thursday night through Wednesday)
Issued at 255 PM CDT Wed Jun 14 2017
From Thursday night into Saturday morning, a series of weak short
wave troughs will move through the region. These will produce
periodic showers and storms. While the 0-6 km shear is very weak,
the 0-3 km shear does occasionally climb up into the 25 to 35
knot range at time. In addition, there is inverted V sounding in
the sub-cloud layer. As a result, there could be the potential
for some gusty straight-line winds from time to time.
On Saturday afternoon and night, a much stronger short wave
trough will move southeast through the area. While the GFS and
ECMWF have supercell shear ahead of this wave, the amount of
instability varies considerably between them. The ECMWF has the
0-1 km mixed layer CAPES only climbing up into the 1000 to 1500
J/kg range. Meanwhile the GFS has them in the 2 to 3K range. SPC
has a small portion of our area (Fayette and Clayton counties in
northeast Iowa and Grant County in southwest Wisconsin) with a 15%
chance of severe weather. This seems very realistic, because this
is the area which will see the highest amount of instability.
In the wake of this system, below-normal temperatures will move
into the region. These cooler temperatures will continue through
Wednesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 700 PM CDT Wed Jun 14 2017
VFR conditions are expected at the TAF sites through the period.
Look for winds to increase late Thursday morning into the 9 to 13
kt range and depending on how deeply the atmosphere mixes, we
could see a some gusts in the 25 to 30 kt range.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Boyne
LONG TERM...Boyne
AVIATION...Wetenkamp
Area Forecast Discussion
National Weather Service State College PA
1005 PM EDT Wed Jun 14 2017
.SYNOPSIS...
A front stalled over southwestern PA will begin to lift back to
the northeast as a warm front on Thursday and Friday. This will
keep the mention of showers and thunderstorms in the forecast
into the weekend.
&&
.NEAR TERM /THROUGH THURSDAY/...
RAP meso-anal still shows some modest instability over western
PA and the RADAR still shows a lonely cell over southern Somerset
county.
My Laurel Highlands zones remain the focus of where the best
chance of rain will be overnight, but the coverage should
remain fairly small with just isolated showers or a
thunderstorm.
It will be another mild night with lows averaging 5-10 deg
warmer than normal.
&&
.SHORT TERM /THURSDAY NIGHT/...
Shower/thunderstorm coverage increases on Thursday from west to
east with frontal boundary in the region with decent low level
moisture and CAPE in place. WPC shows western zones with a
marginal risk of excessive rainfall Thu. Given FFG values,
lowered by the recent spell of dry weather, coupled with
forecast rainfall, expect rainfall may be more beneficial than
problematic and any flooding threat to be very localized urban
or small stream issues. Will monitor going forward for the need
of a flash flood watch for western zones.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Model and ensemble guidance remain in good agreement on the
development of a modestly strong mid/upper level trough over the
Great Lakes by Monday, with multiple waves progressing around
the base of the trough and ejecting northeast into Canada. The
most likely period for showers and thunderstorms (Sun-Mon) will
focus along the associated surface cold front which is progged
to slowly push southeast and reach the Mid Atlantic coast by
20/12z. Temperatures are fcst to trend above average over the
weekend with max readings in the mid 80s to low 90s on Sunday.
Max heat index is projected to reach the mid 90s across portions
of the mid-lower Susquehanna Valley. Unlike the recent heat
episode, the duration of hot temperatures is expected to be
shorter (1 possibly 2 days max - with limited area /SEPA/ on
Monday). Lower humidity and near average temperatures are likely
following the cold frontal passage into the middle part of next
week.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR conditions for all TAF sites this afternoon and overnight.
Lower CIGS in showers and thunderstorms more likely on Thu/Thu
evening with frontal system in the area. Unsettled weather
continues Friday into Saturday.
.OUTLOOK...
Fri...Low cigs, showers/tstorms possible, mainly in the AM.
Sat-Sun...Patchy AM fog possible. Isold PM tsra impacts
possible.
&&
.CLIMATE...
Record high at Harrisburg (95F in 1956) was broken yesterday.
High at Harrisburg yesterday was 96 degrees. Record report
sent out.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...Ross
LONG TERM...Steinbugl
AVIATION...Ross/Ceru
CLIMATE...
Area Forecast Discussion
National Weather Service Wilmington OH
919 PM EDT Wed Jun 14 2017
.SYNOPSIS...
A warm and moist airmass will lead to an unsettled weather
pattern through the weekend. A drier and cooler airmass will
settle into the area early next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Line of showers and thunderstorms was moving into east-central
Indiana at 00Z. Just within the past hour or so, have observed
significantly less lightning and this adds support that this
line is weakening. Still, for at least a couple more hours,
there is the risk for strong gusty winds affecting areas of
east-central Indiana/far western Ohio. Then the risk will
diminish by late evening as suggested by most guidance,
although remnant showers may extend all the way toward central
Ohio by midnight.
Thereafter, models including high resolution guidance have
struggled with the potential for additional convection
overnight. There exists considerably higher uncertainty than
usual for a first period forecast. In this warm/moist
environment and with small scale boundaries lurking, certainly
can`t rule out the risk for overnight convection (am already
seeing some new development in south central Indiana that will
likely affect our southwest CWA), however am leaning toward the
idea that any stronger/more widespread convection that develops
for the overnight would remain to the southwest of the CWA as
some of the most recent HRRR runs are suggesting.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Although the evolution of scattered activity in the near term
period has a degree of uncertainty to it, the consensus on
Thursday`s activity is ironically a bit more focused.
Latest guidance has trended a bit slower with the weakly-defined
cold front expected to progress from west to east through the FA
during the short term period before it inevitably washes out
somewhere in the Ohio Valley. As such, trended PoPs a bit slower
for Thursday late afternoon and evening.
Destabilization will occur through the afternoon and evening
and convection will eventually develop during the heating of the
day before slowly progressing eastward through the evening. With
continued high PWATs in excess of 1.5," pockets of heavy rain,
and a corresponding localized flooding threat, will be possible.
Strongest activity will also yield a threat for locally
damaging winds. Will continue to highlight this potential in the
HWO.
With a bit less cloud cover expected through the first part of
the day on Thursday, temperatures may nudge up into the upper
80s in a few spots. Have trended highs several degrees above
guidance to account for this potential.
Drier conditions will return Thursday night as slightly drier
air moves in and best forcing most east of the FA. Slightly
cooler temperatures are expected, with lows generally in the
mid/upper 60s.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
The immediate long term period will feature a quasi-westerly flow
pattern aloft with embedded weak disturbances rippling through this
flow from time to time Friday into Saturday. Timing of these
disturbances is somewhat problematic and whether it will coincide
with max diurnal instability. As such, will maintain a low threat
for showers/storms during this period. It will remain warm and humid
both days with highs in the upper 80s to near 90 and lows in the 60s
to around 70.
It still looks like a bona fide mid level trough will be poised to
traverse the Great Lakes and Ohio Valley Sunday into Monday. A cold
front associated with this trough will interact with a moist and
unstable airmass to bring the highest confidence/coverage for
showers/thunderstorms, particularly Sunday into Sunday night. Will
continue with likely PoPs. It will be warm again on Sunday with
highs in the mid and upper 80s.
We should begin to dry out on Monday as the front moves east.
Surface high pressure is forecast to build into the Ohio Valley
Monday night, moving east on Tuesday. Temperatures will cool back
down into the upper 70s and lower 80s with lows in the 60s.
A weak front may swing into the region on a northwest flow Tuesday
night into Wednesday, bringing the next chance for showers and
thunderstorms. Temperatures will be near seasonal normals.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Line of showers and thunderstorms across central IN will
continue moving to the east through this evening. Highest
confidence of impact at a terminal will be DAY around or shortly
after 02z with reduced visibility and potential gusty winds.
Confidence with the line extending further south into the
CVG/LUK areas is lower and thus only have VCTS at this time. In
addition, further east toward the Columbus terminals, expect a
weakening trend late this evening and therefore only have
mention of VCSH after 03z.
Models, including high resolution guidance, have provided
differing solutions for overnight/Thursday. Some model runs have
suggested some renewed convective activity late tonight/early
Thursday while others have been suggesting generally dry
conditions with thunderstorms returning during the
afternoon/evening. Have leaned toward the latter solution at
this time, focusing on the greater likelihood of convection
linked to the diurnal cycle.
OUTLOOK...Thunderstorms are possible Saturday through Sunday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...KC
NEAR TERM...BPP
SHORT TERM...KC
LONG TERM...Hickman
AVIATION...BPP
Area Forecast Discussion
National Weather Service Lincoln IL
856 PM CDT Wed Jun 14 2017
.UPDATE...
Issued at 856 PM CDT Wed Jun 14 2017
The strength of the storms in our forecast area /FA/ has
decreased, with mainly showers and a few storms still active. A
few stronger updrafts just west of Scott County could maintain
strength as they approach the SW corner of our FA. An axis of
instability remains across our southern counties, so the Severe
Watch will be allowed to continue through 10 pm for now. Overall
trends show the focus for storms should shift south of our
counties by midnight, with spotty showers/storms still possible
farther north toward Peoria later tonight. The lack of a tangible
trigger for storms farther north lowers confidence on coverage,
but the high res models have been consistently showing a line of
showers from west to east near Peoria after 09z. So have continued
slight chance PoPs through the night even for our northern
counties.
Cold pool outflows from the evening convection have altered the
temperature profile across central Illinois, but the overall
flavor of the low temps should still hold. We expect upper 60s and low
70s for lows in general, which means some areas may see steady
temps for the rest of the night as the air mass recovers from
rainy-cooled air back toward the antecedent air conditions.
The main updates this evening were to PoPs and weather to match
expected trends. The remainder of the forecast looked on track.
Updated info is already available.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 259 PM CDT Wed Jun 14 2017
Potential for strong to severe storms will continue into the early
evening, as a 500mb shortwave lifts northeast across the area.
MUCAPEs of 3000-4000 J/kg late this afternoon will diminish
steadily this evening. Low level helicity of 150-200 m2/s2 will
provide some rotational tendencies in the stronger storms that
persist longer. However, DCAPE values of 1500-1700 J/kg will
dominate the convective mode and damaging winds appear the more
likely severe hazard. Half inch hail will be possible, but
freezing levels over 14000 FT will diminish the potential for
large hail. The melting hail could boost potential for very heavy
rainfall rates over short periods of time, where 1 inch of rain
falls in as short as 15 minutes. The ground is predominantly dry
to start, so flash flooding potential will be diminished in
general, but could still occur in low lying and poor drainage
areas.
Both of our Severe Thunderstorm Watches expire at 01z/8pm, but
our southeast counties could need an additional hour or two added
to the watch, if the NAM-nest model verifies. HRRR shows the
current wave exiting into Indiana by 23z/6pm, with another flare-
up of weaker storms west of I-55 between 01z-04z.
In addition, we are still seeing some indication of a late night
low level jet triggering a few showers/storms north of a line from
Rushville to Bloomington, so PoPs were continued in our NW
counties until 11z. Coverage may not be enough to warrant the
likely PoPs we previous had after 06z, so late night PoPs were
lowered a bit.
A few showers/storms could linger in our eastern counties Thursday
morning, mainly east of I-57 but possibly as far west as I-55
toward sunrise. Then some clearing is expected, setting the stage
for another hot and humid day. High temps will reach the 88 to 93F
range, with the cooler temps toward the Indiana border due to
morning convection. Muggy sfc dewpoints in the upper 60s and low
70s will linger another day.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 259 PM CDT Wed Jun 14 2017
A zonal flow south will prevail across the Midwest for the first
part of the extended forecast. That will allow the next wave in a
series of shortwaves to affect areas west of the Illinois River
late Thursday night, with storms expanding across the remainder of
Illinois on Friday. The overall strength of that system appears
weak, but instability will be supportive of isolated severe storms
late Friday afternoon into early evening, mainly west of I-55.
Another stronger wave is projected to arrive later Friday night
into Saturday, triggering additional storms, and prompting higher
chance and some low likely PoPs. An intensifying nocturnal LLJ may
increase potential of wind damage with those storms.
The last wave of the weekend will be a cold frontal passage
Saturday night into Sunday, bringing chances of strong storms once
again. The timing of that squall line looks to put areas west of
I-55 in the higher chance Sat evening, with high chances expanding
east of I-55 after midnight and continuing south of I-70 Sunday
morning.
That front will usher in a change in air mass for early next
week. Expect cooler weather for at least the first two days of
next week, with high temperatures in the lower 80s Monday and
Tuesday, and overnight lows dipping into the upper 50s and lower
60s. A few spotty showers/storms will be possible Tuesday
afternoon and evening due to a weak shortwave, but most areas
should remain dry. A warming trend will begin on Wednesday, as
southerly winds return and highs climb back toward the mid to
upper 80s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 639 PM CDT Wed Jun 14 2017
The storms have become focused in west-central Illinois, and there
appears to be enough of a mid-level trigger to keep those storms
progressing to the east and eventually S-SE. There is enough
instability that will continue above the stabilizing ground level
layer to fuel continued development of potentially severe storms.
SPI and possibly DEC may be affected by the current complex of
storms. Only included a tempo for IFR conditions at SPI, and will
monitor the need for one at DEC. The remaining TAF sites should
remain north of the storms, but a few showers could linger across
the remainder of central Illinois this evening. Overall, VFR
conditions will prevail for most of the next 24 hours, except for
during a thunderstorm if one hits a TAF site.
Tomorrow morning, a few showers/storms could develop east of I-57,
and possibly affect CMI. However, several high res models do not
show that morning wave of convection, so have not included any
precip after 12z at CMI.
Prevailing winds will remain south to southwest due to Illinois
remaining in the warm sector throughout this TAF period. Wind
speeds should remain 10kt or less, under a weak pressure gradient.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...Shimon
LONG TERM...Shimon
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Louisville KY
819 PM EDT Wed Jun 14 2017
...Updated Aviation Discussion...
.Forecast Update...
Issued at 636 PM EDT Wed Jun 14 2017
Outflow boundary reaching from northern Indiana to middle Tennessee
is slowly sliding to the west, and is entering Louisville at the
time of this writing. Showers and a few small thunderstorms are
being forced up by the boundary, but are remaining isolated and
relatively weak -- the gust front is not providing much of an
impetus as it moves only very slowly and has surface winds of only
around 10 mph behind it, plus AMDAR soundings show a cap around
12k`. As the sun continues to lower, thunderstorm chances will lower
as well, leading to a quiet evening for many.
Right now the convection in central Indiana is expected to stay just
north of the LMK CWA, but it will need to be watched for any
southward development as it encounters the gust front coming in from
the east.
Attention will then turn to the possibility of showers and
thunderstorms moving in from the northwest after midnight. Another
outflow boundary is currently seen in radar data from southwest
Indiana into central Illinois, and may help to focus convection
tonight.
&&
.Short Term (Now through Thursday Night)...
Issued at 210 PM EDT Wed Jun 14 2017
Sufficient heating and now some triggers expected to come upstream
to develop storms first this afternoon generally east of I-65 and
then more storms coming in this evening from the west. Downdraft
CAPEs are pretty high over our area according to RAP and LAPS data.
Would not be surprised to see a good cold pool organize and blast
into our energetic environment to maintain stronger storms into our
region. The line should decay as it progresses farther east later
this evening...or it may turn southward into central TN.
In the wake of this system, we should have a quiet morning Thursday,
but another wave moving in from the west in the afternoon should
allow for new development, as per the latest ARW-WRF. These storms
will have a little more wind aloft to work with, so they should move
faster than the more pulsy-type storms this afternoon. They may be
able to mix down a little stronger wind gusts. Lastly, precipitable
waters will be fairly high, so despite the faster motion, will have
to watch for localized flood potential.
Given cooling with the rains, will go a little lower for
temperatures in the morning, but given more insolation possible
during the day will bump temperatures up for the afternoon. Thursday
night, again in the wake of preceding rains for most of the region,
should once again cool down. Dewpoints dropping a few degrees will
help with that too.
.Long Term (Friday through Wednesday)...
Issued at 210 PM EDT Wed Jun 14 2017
The trend for Friday continues drier, despite a trough moving across
the region. Precipitable waters drop to the the low 1-inch range,
but with some better moisture trying to pull in from the west, but a
little behind the better forcing. Thus plan to keep the daytime
period dry Friday, which makes us warm again. Saturday, we get
another in a string of multiple disturbances move across us, but
this time with that better moisture out west over us instead. That
should set up isolated to scattered storms.
Better coverage is expected Sunday/Sunday night as a longwave trough
moves through the Midwest. The GEM/GFS/00Z Euro/GEFS all have good
consistency on a long swath of precip along a front associated with
this system. Timing here again could lead to some severe potential,
so something to watch for over the next several forecast cycles.
Temperatures both weekend days should continue above normal.
Behind this longer-wave system, we should cool off and dry out at
least to start the work week. Zonal flow with some disturbances
return again for midweek.
&&
.Aviation...(00Z TAF Issuance)
Issued at 751 PM EDT Wed Jun 14 2017
Convection that is currently in northeastern MO and western IL
is the greatest threat to aviation for SDF, LEX, and BWG. If this
system remains organized, it will start to move southeast towards
KY. Some models have been too optimistic today, so their arrival at
SDF and BWG has been pushed back to 9z and to 15z at LEX.
Uncertainty remains high to the exact timing and strength of showers
or thunderstorms. Thunderstorms were left out of the TAFs for this
reason. Wind will veer from south to southwest. Expect rain to move
out of central KY by tomorrow evening.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...13
Short Term.....RJS
Long Term......RJS
Aviation...KDW
Area Forecast Discussion
National Weather Service Nashville TN
904 PM CDT Wed Jun 14 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
A bit less convective activity tonight over the mid state compared
to last night, so quiet evening so far. Short term models such as
the HRRR are suggesting convection will move in from the northwest
before sunrise, so adjusted pops just a bit. Current MCS
developing near STL looks to be the culprit for development
overnight. Also added mention of fog in eastern zones since
dewpoint depressions on the Plateau are already under 3 degrees,
and would not be surprised to see a few areas see some patchy fog
development. Otherwise rest of the forecast looks to be on track.
&&
.AVIATION...
00Z TAF DISCUSSION.
Only some isolated showers across Middle Tennessee this afternoon
so will just mention VCSH at CSV. HRRR/NAM models insistent on an
MCS forming across MO/IL and diving south into our area late
tonight/Thursday morning, so will mention VCTS at all airports
and TSRA at CKV. Otherwise, light south to west winds are expected
along with VFR conditions.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Barnwell
AVIATION........Shamburger
Area Forecast Discussion...UPDATED
National Weather Service Norman OK
939 PM CDT Wed Jun 14 2017
.UPDATE...
Made small adjustments to hourly grids tonight.
&&
.DISCUSSION...
Chances for additional severe storms appear to be very low for the
rest of tonight. Increasing CINH with the loss of daytime heating
along with the lack of large scale lift have caused a decrease in
storm coverage and intensity this evening.
Generally kept 20% for storms for the rest of tonight in most
locations, generally east of a surface dryline from Cheyenne to
Woodward, and anywhere north of a Archer City, Texas to Ada line
where the cap may be just weak enough for isolated activity. The
low level jet may increase enough to allow for additional storms
to form, particularly over north central Oklahoma near Enid and
Ponca City based on latest operational and experimental HRRR runs.
Not confident that additional storms will occur tonight. However,
cannot completely rule out a stray strong or severe storms with
large hail, damaging winds, and locally heavy rainfall due to high
potential elevated instability (MUCAPE 2000-4000 J/kg) and
abundant low level moisture (surface dewpoints mainly in the upper
60s and lower 70s). Storm coverage should remain sparse.
Warm and muggy weather will prevail with overnight low
temperatures in lower to mid 70s across most locations tonight.
Products will be updated shortly.
MBS
&&
.PREV DISCUSSION... /issued 733 PM CDT Wed Jun 14 2017/
UPDATE...
Made a few adjustments tonight, mainly to alter rain chances
before midnight.
DISCUSSION...
Some severe thunderstorms remain possible tonight. Exact storm
evolution tonight remains very uncertain.
Latest satellite and radar imagery at 730 pm CDT depicted a line
of cumulus near a weak surface boundary/dryline from near Hollis
to Clinton to Fairview to Medford, Oklahoma. A few showers were
detected by radar near Clinton. Scattered severe storms were
located between Abilene and Lubbock, Texas.
So far, sufficient capping and the lack of large scale lift have
prevented storm development in Oklahoma and western north Texas.
This may change over the next 1-2 hours as latest models indicated
weak cooling at 700 mb (especially in northern Oklahoma) which
would weaken the low level cap. Also, a slight increase in the low
level jet could aid in lifting the air. The greatest potential
for storm development is near the dryline/surface boundary
mentioned above in the next 1-2 hours. Still, not sure about storm
coverage tonight due to the lack of large scale lift. Left moving
storms capable of large hail and heavy rainfall between Lubbock
and Abilene may move into far western north Texas (Knox county)
around 9 or 10 pm, assuming they hold together which is doubtful
as low level CINH may increase.
Rather high instability (MUCAPE 2000-4500 J/kg) and sufficient
shear (0-6 km 25-40 kt) would support severe thunderstorms (some
supercells and multicells) capable of very large hail and damaging
winds if storm initiation does occur in the next few hours.
Storms would generally move east around 20 mph. If enough storms
could occur, a cluster or two could form somewhere and dive south
or southeast later tonight. There would be an outside chance for
locally heavy rainfall and flash flooding as well if storms
develop tonight. Overall, kept 20% chance for storms tonight in
most areas southeast of the surface dryline.
Products will be updated soon.
MBS
PREV DISCUSSION... /issued 545 PM CDT Wed Jun 14 2017/
AVIATION...
VFR conditions to continue. Winds will relax some this evening with
a transition from northeast to southeast at GAG/WWR as sfc boundary
lifts back north across those sites. Otherwise, isolated storms may
occur this evening, but chances remain too low to mention at this
time.
30
PREV DISCUSSION... /ISSUED 335 PM CDT Wed Jun 14 2017/
DISCUSSION...
A weak surface boundary lies across Oklahoma this afternoon,
approximately from Medford to Clinton to Hollis. To the northwest
is somewhat less humid air, and slightly lower temperatures, along
with variable or northeast winds. Weak convergence along this
boundary may be sufficient to generate a few thunderstorms later
this evening. Substantial CAPE with a relatively weak vertical
wind profile should result mainly in disorganized storms with
hail/wind as the biggest threats.
Subtle features in the synoptic scale flow will have an effect on
exactly what happens tomorrow. Some models are enthusiastic about
a large MCS forming over Kansas and then moving south into
Oklahoma tomorrow evening, supported by a weak mid-level wave.
There is enough of a chance of this happening to warrant higher
PoPs tomorrow evening/night.
An upper-level ridge will then build over the region for Friday
and Saturday. It will be hot enough both days that we could see
a few "popup" storms, but nothing organized is expected.
An upper wave and associated surface front will bring another
chance of storms Sunday and perhaps into early next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 73 96 72 96 / 20 20 30 0
Hobart OK 73 97 73 99 / 20 20 20 10
Wichita Falls TX 75 97 75 99 / 20 10 20 0
Gage OK 70 99 70 98 / 10 30 20 10
Ponca City OK 73 96 71 96 / 20 20 50 10
Durant OK 76 95 75 96 / 10 10 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
17/30
Area Forecast Discussion
National Weather Service Tulsa OK
930 PM CDT Wed Jun 14 2017
...UPDATE...
.DISCUSSION...
Isolated convection had developed this evening along a surface
boundary located across the Texas Panhandle through Northwest
Oklahoma into Central and East Kansas. Weak upper flow had
provided a slow movement...around 15kt or so for the ongoing
storms across Western Oklahoma and Southeast Kansas. Ahead of this
activity...mostly clear skies and southerly winds were common
across Eastern Oklahoma and Northwest Arkansas.
Overnight tonight...the ongoing isolated convection is expected
to slowly develop into southward moving MCS while the surface
boundary retreats west northwestward. Latest short term model
solutions try to push this MCS south through Northeast Oklahoma.
Indications are that a second MCS could also develop over Eastern
Kansas/Western Missouri and move east southeast perhaps affecting
parts of far Northeast Oklahoma and Northwest Arkansas late
tonight. Last few HRRR model runs have shown a little more eastern
progression with this possible second MCS...keeping it mostly
north of the CWA. In response...have updated pops to account for
the ongoing storms potentially dropping south into the region with
lesser chances eastward overnight. Weak flow/shear and an
increasing cap should help to limit overall severe potentials.
However...an isolated strong/damaging wind gust will remain
possible mainly over Northeast Oklahoma.
Also overnight...increasing cloud cover combined with the
dewpoints remaining in the upper 60s/low 70s...low temperatures
tonight should again hold in the around 70 to mid 70 degree range
over the CWA. Added minor tweaks to temp/dewpoint/sky/wind grids
for the evening update to account for latest trends and
observations. The rest of the forecast for now seems to be on
track.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 76 96 73 93 / 40 20 40 10
FSM 74 96 74 96 / 20 20 20 20
MLC 75 93 74 94 / 10 20 20 10
BVO 72 94 68 93 / 30 20 50 10
FYV 71 90 69 90 / 30 30 20 20
BYV 73 91 70 90 / 40 30 20 20
MKO 73 94 72 92 / 20 20 30 10
MIO 73 94 72 92 / 30 20 40 10
F10 74 93 72 93 / 40 20 40 10
HHW 74 94 75 95 / 10 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...20
AVIATION.....30
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
525 PM MDT Wed Jun 14 2017
.DISCUSSION...(This Evening Through Wednesday)
Issued at 259 PM MDT Wed Jun 14 2017
Water vapor imagery shows upper low continuing to drift over south
central Canada north of North Dakota. A shortwave is sliding west
over north central Wyoming with storms developing on the leeside of
the Bighorns. Models show weak instability across northeast Wyoming
into western South Dakota...with Cape values under 500 J/KG. HRRR
shows the Wyoming storms moving into northeast Wyoming late this
afternoon and over the Black Hills in the early evening. Storms then
push eastward into central South Dakota by mid evening. Have
expanded areal coverage of isolated pops...but is expected to remain
isolated. Rest of the night will be dry and mostly clear with lows
in the 40s to mid 50s.
Weak ridging on the backside of the upper low will keep dry weather
across the CWA through Friday. Highs Thursday and Friday will be in
the upper 70s to upper 80s. There could be isolated shower/storms
develop across the Black Hills Friday afternoon. Upper flow will
become zonal through the weekend with several shortwaves crossing
the northern plains. A stronger shortwave is progged to cross
Montana/northern Wyoming late Friday night into Saturday along with
a cold front. This will bring the best chance of precipitation over
the next week...especially over northwest South Dakota. Cooler temps
behind the front are expected for the weekend with highs in the
upper 60s to upper 70s. Strong upper ridging will build back into
the region early next week with dry weather and a warming trend.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Thursday Evening)
Issued At 524 PM MDT Wed Jun 14 2017
VFR conditions will persist through the period. Gusty winds over
northwest SD will subside this evening. A patch of -SHRA/-TSRA
will move from northeast WY through the Black Hills into central
SD this evening.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION...13
AVIATION...Helgeson