Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/19/17
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
548 PM MDT Sun Jun 18 2017
.AVIATION...
00Z TAF CYCLE
Isolated showers and thunderstorms are sluggishly taking shape over
the high terrain surrounding the continental divide of western New
Mexico and the far northern mountains early this evening. These
storms have been producing more wind than downpours, but activity
should steadily diminish after sunset. A similar weather regime will
persist into Monday with isolated showers and thunderstorms taking
shape over the high terrain in the afternoon. Prevailing breezes will
be light to moderate, but erratic and gusty conditions will be
possible in/near any showers or storms.
52
&&
.PREV DISCUSSION...310 PM MDT Sun Jun 18 2017...
...SIGNIFICANT HEAT WAVE TUESDAY THROUGH FRIDAY...
.SYNOPSIS...
The Four Corners high currently located over southern Nevada will
shift eastward during the next couple of days. Moist southeast winds
at the surface will keep isolated afternoon and evening showers and
thunderstorms possible through Tuesday, mainly mountains and east.
Temperatures will warm to near record or record levels Tuesday,
continuing through the work week. A strong backdoor cold front is
expected to bring relief to the hot conditions Friday night or
Saturday. Low level moisture will increase behind this front as well,
brining chances for showers and thunderstorms next weekend.
&&
.DISCUSSION...
Higher dewpoints all around today as a backdoor cold front brought
low level Gulf moisture to the east and central and north winds
brought Pacific moisture into far western areas this morning.
Unfortunately, the good lapse rates across wrn NM do not coincide
with the best low level moisture which is across ern NM. Isolated
showers and thunderstorms still possible mainly northern and western
mountains but they`ll be on the dry side. Low level sely flow
continues overnight, becoming more ely on Monday. This low level Gulf
moisture transport will keep isolated afternoon and evening showers
and thunderstorms possible, mainly over the southwest mountains and
central mountain chain, including the Jemez Monday.
Similar condtions are expected Tuesday. Main change Tuesday will be
the increased heat across western and northwestern areas as 700mb
temps climb to near 22C in response to the Four Corners high being
forced upright and farther east to the NM/AZ line. The latest heat
risk indices suggesting that heat advisories may be necessary for the
mid RGV Wednesday and Thursday as high temperatures reach the lower
100s in the ABQ metro both days. Much of eastern NM will be under the
heat gun Wednesday and Thursday as well with temperatures soaring to
between 105-112 degrees, so heat advisories likely there both days.
GFS is now on board with the ECMWF for Friday and beyond. An
unseasonably deep upper level clipper trough moving south and sewd
out of Canada and into the Northern Plains is forecast to send a
potent backdoor cold front into NM Friday night or Saturday. At the
same time, the upper level cool in nwly flow aloft as the Four
Corners high gets forced swwd to near the NM bootheel. This combo has
the potential to set the stage for a much cooler and wetter period
next weekend.
33
&&
.FIRE WEATHER...
...HEAT TO RETURN MONDAY AND BUILD STRONGLY TUESDAY THROUGH
THURSDAY...
The effects of the cooler and more humid air mass will be short
lived as a warming and drying trend commences Monday. The upper
ridge will expand eastward and strengthen over New Mexico this week,
with the high center of circulation shifting over western New Mexico
and eastern Arizona.
So far this afternoon, cumulus were most numerous over the western
mountains. The central mountain chain has been slow to destabilize,
but it appears some cumulus are beginning to sprout at this time. A
few mainly dry showers or storms with gusty winds are still possible
later this afternoon and early evening as indicated by the HRRR and
RAP over the west central/southwest mountains and along the central
mt chain, particularly the Sangre de Cristo mts. Movement would be
generally to the southeast or south if any cells do develop.
Overnight humidity recoveries will be good to excellent for most
areas tonight, although some locales over the far west may be an
exception. Despite a nightly slosh of low level moisture into
eastern New Mexico and possibly to the RGV, daytime humidities will
gradually return to single digit values over nearly all of the
forecast area by midweek as high temperatures heat up. At the same
time, overnight humidity recoveries worsen. Temperatures by midweek
will likely reach near or record values for many locales. Haines of
6 becomes widespread by Wednesday and persists through Friday, and
areas of Super Haines forecast west and central Thursday and Friday.
Some moisture will remain trapped under the upper ridge so isolated
to scattered thunderstorms are possible in the afternoons and early
evenings over the higher terrain through Wednesday before
diminishing Thursday. Some or a majority of those storms will likely
be drier with strong and gusty winds. In addition, some of the cells
may drift off the higher terrain and into the highlands and valleys
late in the afternoons and early evenings.
Vent rates, while generally good Monday and Tuesday, improve to
excellent overall Wednesday and Thursday as mixing heights rise
significantly.
Some relief from the heat may come at the end of this week. The
upper high center slips back to the south over Old Mexico, allowing
a moist front to push into the eastern plains and westward through
the RGV, similar to what was experienced last night/early this
morning.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Bismarck ND
951 PM CDT Sun Jun 18 2017
.UPDATE...
Issued at 951 PM CDT Sun Jun 18 2017
Quick update to blend in current conditions and adjust pops to
cover ongoing radar trends. The latest HRRR and NAM both suggest
lesser pops lingering late tonight, so shaved those back a little
too.
UPDATE Issued at 706 PM CDT Sun Jun 18 2017
Scattered showers and isolated thunderstorms continue early this
evening. A few strong storms have managed to develop from time to
time in a environment marked by SBCAPE of up to 1500 J/KG. The
earlier concern for a few funnel clouds has decreased with the
non-supercell tornado parameter weakening over the past few hours.
Main change for this update was to adjust pops to better match
current radar trends.
&&
.SHORT TERM...(This evening through Monday)
Issued at 305 PM CDT Sun Jun 18 2017
Scattered showers and isolated thunderstorms through this evening,
with some concern for weak funnels and/or a landspout in north
central ND. Another round of showers and isolated thunderstorms
are forecast Monday afternoon central ND.
For the near term, now through this evening, the latest SPC
mesoscale analysis indicates Non-Supercell Tornado Parameter
values between 2 and 4 centered over north central ND.
Contributions coming from strong surface vorticity combined with
surface based CAPE of 1000 J/Kg, steep low level lapse rates, and
little to no 0-6km shear. Will continue to monitor as isolated
showers/thunderstorms continue to develop over southeast Saskatchewan
and move into this environment. Except in the southwest, most
unstable Cape this afternoon is between 500-1000J/Kg with mid
level lapse rates at 6.5C/km. Effective Shear is weak, less than
20kt across all of western and central ND, which is expected to
remain that way for the rest of the afternoon per BUFKIT RAP
soundings. Thus, outside of the potential for weak funnels/landspout
in the north central mentioned above, expect pulse type/ordinary
showers/thunderstorms through the afternoon/evening east of
Highway 83, and also across southwest ND. The bulk of the
precipitation will wane after sunset. Some of the CAM`s suggest an
isolated shower may linger past midnight.
Latest water vapor imagery shows an upper ridge parked over
southern Nevada and an upper low circulating over Ontario. In
between, a northwest flow continues to dominate the northern high
plains. Upstream, another shortwave trough now over northern
Alberta will scoot southeast tonight through Monday. Large scale
ascent from the aforementioned shortwave and also by a 100kt 300mb
jet, per NAM/GFS Q-vector Divergence Field will shift from
central and northern ALberta into northern and central ND 12z
Monday-06z Tuesday. Scattered showers/isolated thunderstorms are
expected to initially develop across far north central ND 12z-18z
Monday, then shift southeast, mainly along and east of Highway 83
and into the southern James River Valley through 00Z Tuesday.
Instability Monday shows most unstable CAPE of around 500 J/kg
with 0-6Km Bulk Shear between 60kt-70kt. This low cape/high shear
environment may possibly favor isolated low-topped but highly
tilted thunderstorms.
.LONG TERM...(Monday night through Sunday)
Issued at 305 PM CDT Sun Jun 18 2017
Upper level flow transitions from northwesterly to zonal Monday
night into Wednesday, then back to northwesterly Thursday through
Sunday. Warm air advection increases Tuesday through Tuesday
night, ahead of a fast moving surface low and associated cold
front and riding along the northern border. A low level jet
briefly sets up Tuesday night per 850mb southerly winds of 40kt to
50kt. A high shear environment with 0-6km bulk shear of 60kt and
70kt and low CAPE becomes evident Tuesday night per GFS BUFKIT
soundings. A strengthening EML develops Tuesday night via
southwest to westerly winds between 5kft and 10kft. Enough of a
capping inversion below the EML, limited moisture through the
column and weak most unstable cape, will limit the threat of
elevated thunderstorms. For now, isolated thunderstorms are
favored in the southern James River Valley. Elsewhere, expect
isolated to scattered showers ahead of a cold front Tuesday night
from west to east, with the highest pops from the Turtle Mountains
into the James River Valley between 06z- 15z Wednesday. Expecting
a breezy to windy day Wednesday. The NAM is weaker with the winds
behind the cold front, while the GFS has a much stronger
northwest wind developing. Used a blend of the given guidance and
CONSMOS for now. Future shifts can evaluate this with the newer
data. Warmest air Tuesday will reside in the southwest with highs
in the mid 80s. This will shift into south central and southeast
ND Wednesday, with 70s across the north
For Thursday through Sunday, periodic showers and thunderstorms
with several shortwaves rotating through the northwest flow.
Cooler with highs in the upper 60s to lower 70s fro most of the
period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 951 PM CDT Sun Jun 18 2017
Scattered showers and isolated thunderstorms have been gradually
diminishing this evening. Confidence in them reaching a terminal
location is not high enough to add a tempo group, so will cover
with VCSH and monitor trends. Gusty west / northwest winds from
Sunday afternoon have diminished this evening. A few showers /
thunderstorms are again possible Monday afternoon, especially from
KMOT to KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...KS
LONG TERM...KS
AVIATION...CK
Area Forecast Discussion
National Weather Service Green Bay WI
634 PM CDT Sun Jun 18 2017
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Monday
Issued at 236 PM CDT Sun Jun 18 2017
The latest rap analysis and satellite/radar imagery show low
pressure lifting northeast away from the region over eastern Upper
Michigan. Back edge of the comma head associated with this cyclone
has moved north of the U.P. border, but additional showers are
popping up beneath broader cyclonic flow aloft with help from a
minor instability. Still some time for a few thunderstorms to
develop this afternoon with surface based capes growing above 600
j/kg over central WI. With upper troughing firmly in place across
the region, precip trends and thunderstorm chances are the primary
concerns in the short term.
Tonight...Upper troughing will remain centered over the western
Great Lakes region. Scattered showers and perhaps a thunderstorm
will linger into this evening, highest coverage across northern
WI. With loss of instability, should see shower coverage and
intensity diminish through the evening. Otherwise, clouds will
remain broken to overcast over northern WI tonight, while areas
over central and east-central WI should see more in the way of
breaks developing. Temps falling into the low 50s north to upper
50s near the Lake.
Monday...Models show a shortwave moving within the upper trough
and across the region during the afternoon. With daytime
instability, should see showers pop over central and north-central
WI by mid to late morning. Highest chances, however, will occur
over eastern WI where ml capes around 500 j/kg will be found
during the afternoon. Will continue the slight chance of a
thunderstorm in this area. Not expecting severe weather, though
any thunderstorms could contain small hail and brief gusty winds.
Highs remaining cool in the mid 60s to lower 70s.
.LONG TERM...Monday Night Through Sunday
Issued at 236 PM CDT Sun Jun 18 2017
Upper level flow will start off northwest Monday night then slowly
transition into a more zonal flow by Wednesday, with the zonal
flowing continuing into Saturday. Models show some differences
this weekend, as GFS/ECMWF turn the flow briefly to the southwest,
while the Canadian hangs on to more of a zonal flow. This is
mainly due to how deep the models dig a trough over the upper
Midwest. These differences should not have a huge impact on the
forecast but does increase uncertainty on how the precip chances
will play out.
A few chances for rain Monday night into Tuesday as weak pieces
of energy move across the area within the northwest flow, but
models have backed off a little on how widespread the shower/storm
chances will be. Will continue to carry low chances for precip,
but thinking much of the time will end of being dry. Brief ridging
moves across the state Tuesday night into Wednesday morning, so
will continue with a dry forecast. The ridge will quickly shift
east as a low pressure system crosses southern Canada, with
associated warm/cold front. These boundaries, along with a push of
warm air advection ahead of the system, looks to be the focus of
one or two areas of showers and storms, all shown by the
GFS/ECMWF/Canadian. Will introduce likely POPs for much of the
area Wednesday evening as models are converging on this period for
the best chance for widespread precip.
The cold front should make it far enough south of the area on
Thursday to keep most shower/storm activity across southern WI,
but can`t completely rule out a shower or storm across central and
east central WI, especially in the afternoon and evening if the
front gets hung up and as a shortwave trough approaches from the
northwest. Models not in the best agreement with this shortwave so
will see how things pan out. Model disagreement continues into
the rest of the long term, as flow becomes northwest again and
timing/location differences of shortwave troughs will need to be
sorted out before any real clarity on when the best chances for
precip will be.
Temperatures will start off below normal within the northwest
flow, climb to near or above normal on Thursday as the area
briefly gets into the warm sector, then settle back below normal
for the end of the week as the warm/hot air gets pushed well to
our south.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 632 PM CDT Sun Jun 18 2017
A broad upper trough will remain across the area the next couple
days. Expect clouds and showers to dissipate with the loss of
daytime heating, though they probably won`t go away completely. An
increase in clouds and showers is expected again by mid-late
morning tomorrow.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Bersch
AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Jackson MS
931 PM CDT Sun Jun 18 2017
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
Another round of thunderstorms and showers are already ongoing in
our northwest region, just north of I-20 and west of I-55, and
will continue to move south in the next couple of hours. Gusty
winds and localized flooding will once again be a concern. An
increase to the POPs over the entire region for the next few hours
have been made, otherwise the rest of the forecast hasn`t
changed. /12/
Prior discussion below:
Tonight through Monday afternoon
An upper level disturbance and a cold front will push southeast
through the forecast area over the next 24 hours. This will
maintain good rain chances across the forecast area from this
afternoon through at least Monday afternoon.
For the remainder of this afternoon through tonight, the disturbance,
coupled with instability from daytime heating in this moist airmass,
and marginal deep-layer wind shear over the CWA of around 30 knots,
will maintain the potential for some severe storms this afternoon
and evening, especially in the north along the Highway 82 corridor.
Storms that indeed reach severe limits will be capable of producing
damaging wind gusts, as well as hail. Frequent lightning and
heavy downpours can be expected with any storms.
Also, an outflow boundary, noted on radar dropping southeast across
Central Arkansas behind a complex of storms moving east across far
North Mississippi, could spark storms across the northern third of
the CWA late this afternoon, that could drop southeast into the
Jackson metro area and Interstate 20 corridor this evening. The
past several runs of the HRRR have repeatedly eluded to this
scenario. Thus, I`ll keep some rain chances in the forecast for much
of the forecast area through at least the first half of the tonight
period. Otherwise, look for partly to most cloudy skies tonight as
lows fall into the 70s.
The aforementioned cold front will begin making its run on the
northwest portion of the forecast area as day breaks on Monday.
Through the course of the day, shower and thunderstorm activity
along and ahead of it will overspread the CWA. Once again, with the
moderately unstable airmass over the region and forcing along the
front itself, could result in the some isolated severe storms across
the CWA during the course of the day Monday. Again, damaging wind
gusts will be the primary concern, with hail possible to a lesser
extent.
However, and perhaps of a larger concern, with precipitable H2O
values around the 2 inch mark on Monday, in addition to the general
west to east orientation of the front as it drops south through the
CWA during the course of the day, heavy rainfall rates could result
in localized flash flooding across the CWA. This will especially be
the case if slow-moving convection, producing high rainfall rates,
trains across the same locales. Soils across a good portion of the
CWA are already saturated from recent heavy rainfall that developed
across the CWA at the end of last week. Thus, any additional heavy
rainfall amounts could further increase flash flooding potential
across the area. As a result, I`ve introduce a "Limited" threat for
flooding across the CWA for Monday.
Surface winds will become northerly behind the front with slightly
drier air beginning to seep into the region. High pressure will
slowly build into northern portions of the CWA late in the day, with
rain chances gradually coming to an end across the north in its
wake. /19/
Monday night through the week...
By Monday evening, the front should be across the southern portions
of my CWA. Storms will likely be ongoing around the front, some of
which could be strong to severe at times. Given forecast PW levels
around 2.0-2.1 inches(nearing daily highs for June 19th), this could
lead to some locally heavy rainfall and localized flooding issues.
The front should eventually wash out by early Tuesday. Some drier
air may be possible generally along and north of the Natchez Trace
behind this front, which would drop PW values to around an inch.
However, no substantial dry air is expected. Dewpoints will drop to
the mid to upper 60s rather than the lower 70s.
The remainder of the long term completely hinges on what will occur
with the likely tropical system in the Gulf of Mexico. Currently,
the National Hurricane Center gives this a high likelihood of
developing into a tropical system within 48 hours. Confidence is
good that it will track into the Gulf but after this, models
continue to disagree. Some models linger the system just offshore of
the Texas to Mississippi coasts through Wednesday before the
developing ridge across the Atlantic pushes east across the
Southeast and causes the system to move inland to our west somewhere
within a weakness. Other models bring it ashore quicker. It is
simply too early to know what will occur with this system. Today`s
model runs mostly take it over our area and to our west, and not
east across Florida as the ridge pushes it further to the west. If
this occurs, drier air will not infiltrate our region. Instead, more
moisture(PW values nearing 2-2.7 inches for locations in the central
and eastern part of the state) will actually move in from the Gulf
as well as higher chances for rain. The official forecast for this
afternoon will include at least chance POPs for much of the mid to
latter parts of the week into the weekend. By the weekend, another
front looks to move through the region which will continue our
higher rain chances. Temperatures this week will remain the 80s as
rain and cloud cover should limit highs getting too much warmer and
overnight lows will remain mild in the lower to mid 70s. /28/
&&
.AVIATION...
00Z TAF discussion:
The proximity of a cold front will keep scattered to numerous
showers and thunderstorms in the forecast through the period. With
the inclement weather, mostly MVFR conditions will prevail.
Periodic IFR conditions will exist where convection manages to
impact a TAF location, but for the most part these will be
brief./26/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 73 87 71 87 / 52 68 26 25
Meridian 73 87 71 85 / 74 68 33 39
Vicksburg 74 86 71 88 / 42 67 14 12
Hattiesburg 72 89 72 84 / 61 52 34 47
Natchez 74 87 72 86 / 42 56 24 23
Greenville 74 84 68 88 / 52 62 4 3
Greenwood 73 84 68 87 / 55 62 7 4
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
12
Area Forecast Discussion
National Weather Service New Orleans LA
810 PM CDT Sun Jun 18 2017
.SOUNDING DISCUSSION...
A routine sounding terminated over the Joyce Wildlife Management
area southeast of Ponchatoula, Louisiana at a height of 110,000
feet or almost 21 miles above the surface.
Flight was launched after the passage across the station of an
outflow boundary that stabilized the boundary layer significantly.
Above the outflow, there was still about 1600 J/Kg of CAPE, and
the lifted index was -5. Lapse rates had relaxed to about 6.5C/km.
Precipitable water value remained high at 1.85 inches. Freezing
level at 14,400 feet, -20C was at 25,200 feet, and wet bulb zero
at 13,300 feet.
Generally west to southwest winds from launch through 700 mb,
light and variable between 700 and 500 mb, south winds backing to
northeast between 500 and 200 mb, then returning to a southerly
component above that. Peak wind of 37 knots out of the east-
northeast was measured at 34,000 feet. 35
&&
.PREV DISCUSSION... /issued 350 PM CDT Sun Jun 18 2017/
SHORT TERM...
Upper level analysis shows a broad trough extends from Canada to
nearly the central Gulf Coast and is moving eastward. Without any
ridging subsidence in place and ample moisture available, its
pretty much a guarantee showers and thunderstorms will be
developing this time of year.
Numerous showers and thunderstorms have developed across the area,
with the bulk of activity centered along a line from Baton Rouge to
Bogalusa. Movement of convection has been mostly cold pool driven
due to lack of a dominant wind direction in the column, seen on this
morning`s sounding. Latest radar trends would then show that the
stronger storms currently around Baton Rouge will propagate
southward over the next hour or so while storms to the south either
move north or dissipate.
After this current batch of convection wanes through the evening
hours, medium range models indicate that renewed showers may develop
over central MS and move south into the CWA from the north. The HRRR
shows this as well, but differs slightly in timing. The observed
solution will likely be something between those 2.
LONG TERM...
The aforementioned upper trough will slowly move east Monday and
Tuesday before reaching the east coast Wednesday. With little change
in the atmosphere from today to Monday, decided to bump up pops to
60% for SW Mississippi and adjacent Louisiana parishes.
The possibly biggest weather impact comes in the form of tropical
potential middle of this coming week. A tropical wave currently
southeast of the Yucatan Peninsula is likely to develop as it moves
north into the central to western Gulf of Mexico (90% chance of
development per NHC). As it does so, the upper trough will be moving
out of the country and fail to pull this tropical system northeast.
The GFS shows it pulling the feature some while the ECMWF basically
suggests little if any. This is why they have such a range in
placement of the tropical system on Tuesday (south of AL vs South of
Texas). A second upper trough will finally move across the country
mid week, which will bring the low/depression/tstorm inland. Because
of such uncertainty with where it will be in the northern Gulf, the
confidence in the QPF forecast is a blend of the possibilities and
rather low in confidence. Attm, have 3 to 6 inches forecasted across
the CWA from Tuesday through Thursday with highest amounts on the
coast. A NE gulf track and you can cut those amounts in half or
more. A NW gulf track and you can probably double those amounts.
MEFFER
AVIATION...
Lingering borderline MVFR CIGS around 030 at a couple airports
should mostly be prevailing VFR this afternoon into at least early
tonight. Scattered SHRA/TSRA will likely briefly impact terminals
with lower CIG/VSBY and possibly some wind gusts up near or above 30
KT, but for now have only placed VCTS in most of the TAFs. Will
likely update some terminals if more concentrated lines and clusters
of TSRA expand as has been the case early this afternoon along line
from near KMCB to northeast of KBTR. 22/TD
PREVIOUS DISCUSSION...MARINE...
A large degree of uncertainty exists with the forecast through the
end of the week depending of if a tropical low forms in the southern
Gulf or not over the next few days. Given the better run to run
consistency of the European model, have trended toward this model
for the marine forecast. As a result, expect to see a period of
small craft advisory conditions develop over the waters by tomorrow
night and then persist through Wednesday as the low passes to the
south of the coastal waters on the way toward the Texas or Mexico
coast. Currently expect to see the strongest winds over the open
Gulf waters on Tuesday when east winds of 20 to 30 knots with higher
gusts and seas of 8 to 11 feet could occur. For the latter part of
the week, an increased pressure gradient over the Gulf related to
the lingering low over Texas will keep southerly winds of 15 to 20
knots and seas of 4 to 6 feet in place. Tides will likely be above
normal beginning tomorrow night and persisting through the end of
the week.
DECISION SUPPORT...
DSS CODE...Blue.
DEPLOYED...None.
ACTIVATION...None.
ACTIVITIES...Monitoring river flooding.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TONIGHT RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 73 89 74 85 / 20 60 20 40
BTR 75 90 75 86 / 20 60 30 50
ASD 74 89 77 84 / 20 50 40 60
MSY 76 88 78 85 / 20 40 40 60
GPT 77 87 77 85 / 20 30 40 60
PQL 74 87 76 83 / 20 30 40 60
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
801 PM CDT Sun Jun 18 2017
.UPDATE...
801 PM CDT
Updated to include an isolated light shower mention mainly over
northeast IL/southern Lake Michigan next 1-2 hours, as a couple of
sprinkles light/showers have developed from closed-cell stratocu
field recently. Area of better cu development appears to be
correlated beneath tail of mid-level short wave rotating across NE
IL at this time and slight cooling of temps around 650-700 mb.
HRRR and RAP soundings suggest weak instability will diminish by
02-03Z making for a fairly small window for any isolated showers,
thus have updated to include a minimal 15 percent just through
mid-evening.
No other forecast changes anticipated at this time.
Ratzer
&&
.SHORT TERM...
228 PM CDT
Through Monday...
Stratocumulus clouds in the cold advection regime have filled in behind
upper level low pressure to our northeast. West winds will
continue gusting to 25-30 kt as a fairly tight pressure gradient
sits over northeast IL with a fairly deep summer time low over
upper Michigan. There are a few showers upstream, but the cu
field will be fairly shallow and coverage should be low.
Clouds thin tonight and west winds will ease, but expect a
similar situation tomorrow though with a bit lighter west wind as
the main surface low will shift farther northeast across Ontario.
We remain in northwest flow behind upper level low pressure, a
pattern that favors diurnally driven showers, but better shower
coverage potential is expected Monday as several models depict a
modest wave in the flow. A few thunderstorms are also possible,
with these showers forming as early as mid to late morning.
Temperatures look to fall slightly cooler than today`s, with
readings generally topping out in the mid 70s.
KMD
&&
.LONG TERM...
232 PM CDT
Monday night through Sunday...
Northwest flow still expected to be in place at the start of the
period, with broad upper level trough across the eastern half of
the CONUS. In this pattern, will see continued stream of mid level
energy move overhead with guidance trying to pick up on some more
energetic waves to move over the area. Some variability, but the
first stronger wave looks to arrive sometime Tuesday morning. This
could provide a more solid area of showers for the area, however,
looks to quickly depart to the east during the day. Instability
not appearing to be too high at this time but with the possible
stronger forcing, have continued mention of slight chance thunder.
CAA will be a persistent feature during this time, with near
normal temps expected Tuesday.
Upper level trough begins to shift to the east by mid week with
more zonal flow returning to the region. In this setup, region
would be favored for mid level energy to stream overhead, which
guidance is indicating into the end of the work week. Periods of
showers and thunderstorms will be once again possible, with more
widespread coverage returning by late Wednesday into Wednesday
night. This will be ahead of a developing trough of low pressure
and frontal boundary, with guidance indicating will remain across
the region Thursday into early Friday. This would make sense given
there does not appear to be any real big support to help kick
this out of the region. With this in place, additional
thunderstorm chances are possible during this time.
Rodriguez
&&
.AVIATION...
For the 00Z TAFs...
627 pm...Only forecast concern this period is a chance for
thunderstorms Monday afternoon.
An isolated shower is possible this evening but no mention in
this forecast with expected low coverage and short duration. A
few showers have developed over southern Lake Michigan late this
afternoon.
Cooler air aloft will spread across the region overnight into
Monday and as a weak upper wave moves across the area on Monday...
isolated thunderstorms are possible. Confidence on coverage is
somewhat low but there is enough of a signal for at least isolated
thunder to include prob mention. Its possible that coverage may
end up being more scattered with increased mention necessary with
later forecasts. Activity should be mainly diurnal with a
weakening and dissipating trend late Monday afternoon into Monday
evening.
Westerly winds will diminish quickly with sunset and then increase
again Monday morning with gusts up to 20kts possible. Its also
possible higher/localized gusts may occur with any thunderstorms
that develop Monday afternoon. cms
&&
.MARINE...
232 PM CDT
As low pressure just to the north of the lake has lifted north,
it has continued to strengthen. With this occurring, winds of 15
to 25 KT and even up to 30 KT are likely in place mainly over the
north half of the lake. Winds over the south half have approached
the 15 to 25 KT range, but do think winds have generally stay
confined to 10 to 20 KT. As this low lifts further to the
northeast tonight, expect winds to diminish across the entire
lake. Included in this diminishing trends are the current
hazardous conditions occurring over the nearshore. Westerly winds
in place on Wednesday, but with speeds expected to be lower over
the entire lake.
Rodriguez
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Memphis TN
706 PM CDT Sun Jun 18 2017
.UPDATE...
Updated to reduce pops across the northern and western portions of
the Mid South.
&&
.DISCUSSION...
The shortwave and associated mesoscale convective vortex has moved
to the east with showers and thunderstorms diminishing quickly
across northern and western sections. There may be some
redevelopment of showers and thunderstorms later tonight mainly
south of Interstate 40 as a cold front moves south. Later coverage
is still in question as the atmosphere remains worked over from
the afternoon convection. This will be monitored through the
evening and additional updates may be needed.
JLH
&&
.PREV DISCUSSION... /issued 309 PM CDT Sun Jun 18 2017/
Surface analysis this afternoon places a cold front from Lake
Huron back through Indiana, Southeast Missouri, then back through
Northwest Arkansas, and Eastern Oklahoma. Across the Lower
Mississippi Valley. A warm, moist, and unstable airmass is in
place across the Mid-South with temperatures as of 2 PM CDT
ranging from the upper 70s to middle 80s. Showers and
thunderstorms are occurring across much of the Mid-South with the
best coverage near the Memphis metro area as of discussion. Strong
to severe thunderstorm potential tonight into perhaps a portion
of the area tomorrow and rain chances for late this week into next
weekend are the primary concerns in this afternoon`s forecast.
Latest mesoanalysis trends indicate surface based CAPE values
between 3000-4000 J/kg over the forecast area, LI`s approaching -8
and precipitable water values around 2 inches. Strong to severe
thunderstorm potential is possible for the remainder of the
afternoon into early/mid evening across the Mid-South with the
best potential occurring over portions of West Tennessee and North
Mississippi. Damaging winds will remain the predominant severe
thunderstorm threat along with a potential for localized flash
flooding from heavy rainfall. 12Z WRF/GFS/ECMWF indicate a
potential for additional showers and thunderstorms to develop
along the slowly moving cold front across much of the area.
However, the latest HRRR run along with some of the CAM models
including the WRF-ARW and WRF-NMM indicate convective chances may
gradually shift to areas mainly across East Arkansas and North
Mississippi overnight. Evening shift will continue to monitor
trends and adjust forecast as needed. A marginal risk for severe
thunderstorms may extend into portions of Northeast Mississippi
into the day Monday. Meanwhile, drier air will begin filtering in
behind the front bringing a gradual end to rain chances for the
remainder of Monday through Wednesday night.
12Z GFS/ECMWF long term models indicate a tropical wave in the
Caribbean will move into the Gulf of Mexico this week but vary on
the direction it will move with a spread covering anywhere from
the Texas Gulf coast to the Mississippi/Alabama coast.
Nonetheless, models indicate this tropical moisture will
eventually move into the Lower Mississippi Valley towards next
weekend and combine with an approaching cold front to increase
shower and thunderstorm chances for the latter half of the period.
CJC
&&
.AVIATION...
00Z TAFs
TSRA chances will prevail at sub-mentionable levels this evening,
given airmass stabilization from earlier storms. SHRA may persist
into the overnight at TUP, in response to favorable upper jet
positioning and near saturation below FL050. Otherwise, main
challenge is flight conditions once precip and clouds exit.
Northerly winds will bring drier air toward 12Z, with conditions
likely rapidly transitioning to VFR at JBR, MEM and MKL with
daytime heating and mixing.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Norman OK
736 PM CDT Sun Jun 18 2017
.UPDATE...
Increased rain chances this evening across parts of central
and southeastern Oklahoma. Made minor changes tonight mainly to
hourly sky cover and surface temperatures.
&&
.DISCUSSION...
A few severe storms with large hail and damaging winds may occur
tonight mainly southeast of I-44. Locally heavy rainfall and
flash flooding are possible as well.
Latest radars indicated light echoes developing roughly near I-40
including the OKC metro area. These appear to be forming along the
850 mb front. Think this activity will grow upscale and move
south/southeast in the next few hours as the mid level cap around
700 mb weakens due to cold air advection at this level
(temperatures falling below +10C at this level). Latest HRRR
model runs support this solution with storms becoming more robust
and numerous somewhere near a Ada to McAlester line by 11 pm
this evening.
A few severe thunderstorms may occur tonight, mainly in the form
of large hail up to half dollar size as storms will be elevated in
nature, though not confident about this. The 00 UTC KOUN sounding
depicted MUCAPE of 1168 J/kg. MUCAPE values are generally
forecast to be 1000-3000 J/kg anywhere south of I-40 based on
latest RAP model analyses, but appears the cap will be too strong
for any storm development northwest of I-44. Current SPC Day 1
Convective Outlook handles this well. If enough storms could form,
there could be a few damaging wind gusts as well. Locally heavy
rainfall and flash flooding may be a bigger concern tonight with
precipitable water values 1.7-2.2", above the 90th percentile for
this of year, which will support rainfall rates of 1-4"/hr,
especially southeast of a Waurika to Pauls Valley to Shawnee line.
Products will be updated shortly.
MBS
&&
.PREV DISCUSSION... /issued 639 PM CDT Sun Jun 18 2017/
DISCUSSION...
The 00Z aviation discussion follows....
AVIATION...
A cold front now crossing Texas will be the source of lift later
this evening that will probably generate scattered showers and
thunderstorms near the Red River. Already, there is a line of
showers farther upstream along I-40, east of KSNL. As the front
continues to recede to the south, the convective activity is
expected to shift south into northern Texas, south of all our TAF
sites. A few areas of MVFR-level ceilings are likely near the Red
River this evening. Otherwise, expect VFR conditions and light
east/southeast winds overnight into Monday.
CmS
PREV DISCUSSION... /issued 227 PM CDT Sun Jun 18 2017/
DISCUSSION...
Cold front still working its way across south-central and
southeast Oklahoma this afternoon. Chances for scattered to
numerous post=frontal storms will increase this evening and
especially overnight near and just north of this front, primarily
across south-central and southeast Oklahoma, as height falls and
associated erosion of mid-level cap occurs. Large hail will be
possible with steep lapse rates and 20 to 30 knots of shear. Heavy
rain could also become an issue near the Red River of southeast
Oklahoma where models are more persistent on storm formation.
Our cool down will not last long as temperatures expected to rise
to and above seasonal averages by Tuesday. With southwest U.S. upper
ridge attempting to build into Southern Plains ahead of next upper
trough, likely to see 100s again across western Oklahoma and
western north Texas by the end of the week.
Models beginning to show some consistency on frontal timing late
in the week with strong cold front potential late Friday and
Saturday. Still some question on amount/potential of tropical
moisture associated with Gulf system to interact with this front,
but given approaching high amplitude trough, tropical system will
likley be kicked eastward before it can get up this far north.
Regardless, next chance for organized rain and hopefully more
widespread activity appears on tap for the first part of next
weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 62 87 66 92 / 20 0 0 10
Hobart OK 62 89 66 94 / 10 0 0 10
Wichita Falls TX 67 88 69 93 / 20 10 10 10
Gage OK 59 87 63 93 / 0 0 0 10
Ponca City OK 61 85 63 91 / 0 0 0 10
Durant OK 68 87 68 92 / 50 20 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
17/23
Area Forecast Discussion
National Weather Service Pittsburgh PA
917 PM EDT Sun Jun 18 2017
.SYNOPSIS...
Several rounds of showers and thunderstorms expected into Monday
morning as a cold front moves through. Less humid and cooler
weather is forecast early next week.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Showers and thunderstorms will continue overnight as a slow
moving cold front approaches from the west. Current convection
developed ahead of the surface front, and is beginning to fill
in spatially over eastern Ohio. Adjusted PoPs to current radar
trends and towards latest HRRR output, which has handled this
event well so far.
With the severe threat all but over, the focus overnight will
turn to the potential for localized water issues. The slow
moving boundary will allow areas to receive several rounds of
showers/thunderstorms into Monday morning. This is especially a
concern for areas still drying out after several rounds of rain
this past week. Will need to monitor the precipitation totals
closely overnight.
Temperatures will remain well above average, as we remain ahead
of the cold front with plenty of cloud coverage.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Front will finally be south of the ridges around noon Monday,
but a shortwaves digging through the upper trough may support
scattered showers/storms each afternoon through midweek. Surface
ridging may keep the best chances to north of PIT by Wednesday.
Upper trough will keep temperatures a degree or two below
seasonal averages Monday, but moderation back to normal is
expected by midweek.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Although the deep moisture is vacated, a mean upper trough will
be maintained in the Great Lakes region. This trough will
create a progressive flow across the Ohio Valley, leading to
daily chances for showers and storms through much of the week.
By Thursday, temperature will rebound to slightly above-normal
value as low-level moisture increases. The highest chance for
showers and storms will come toward the end of the long term
with the passage of a frontal boundary.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Additional showers and storms will move through the region tonight
and Monday as a cold front completes passage. Brief periods of
evening MVFR can be expected with deterioration thereafter as the
front encroaches. Overall rain coverage will diminish on Monday
morning and a slow improvement to VFR is anticipated although
scattered showers may linger.
.Outlook...
Brief restrictions are possible through mid week as an upper
trough slides over the region.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.
&&
$$
Area Forecast Discussion
National Weather Service Shreveport LA
943 PM CDT Sun Jun 18 2017
.UPDATE...
The quasi-stationary cold front has sagged southward from
southeast OK to across portions of extreme northeast TX tonight. A
few isolated showers have commenced to slowly develop across
northeast TX, whilst more well developed thunderstorms were
ongoing from near Oklahoma City, OK eastward to near Fort Smith,
AR. High-resolution models still hint at further development
along the slowly southward sagging cold front overnight, and if it
hold together, making it to the Interstate-20 corridor Monday
mid-morning. Have elected to maintain highest POPs across the
northern zones /near the front/ early tonight, but dropped POPs
below mentionable levels across portions of central LA given
latest radar trends. In addition, also tweaked the overnight temps
to show temps dropping into the upper 60s across the far northern
zones versus 70s elsewhere, due to the speed of the fropa.
&&
.PREV DISCUSSION... /issued 658 PM CDT Sun Jun 18 2017/
AVIATION...
For the 19/00z TAFs, next round of convection is expected to
develop tonight along a cold front that is currently located from
near KLZK, westward into Oklahoma, and southwest between KGYI and
KF00 towards the DFW Metroplex. These storms should enter the
area and begin impacting the TAF sites from north to south around
19/06z. Convection should be near the Interstate 20 corridor by
19/09z. Storms will continue to move south with the cold front
through the remainder of the TAF period. Model guidance suggests
the storms will weaken and become increasingly scattered Monday
afternoon. Therefore, impacts at KLFK are a bit more uncertain.
CN
PREV DISCUSSION... /issued 229 PM CDT Sun Jun 18 2017/
DISCUSSION...
Morning convection across our extreme northern most zones has
worked over the atmosphere with new convection trying to develop
along further north closer to the frontal boundary which as of 19z
extends from near an SPS/ADM/FSM/FLP line. The front has showed
very little movement over the last couple hours and given the fact
that the morning convection has stabilized the Middle Red River
Valley across Northeast Texas, Southeast Oklahoma and Southwest
Arkansas, timing of redevelopment across this region may be
delayed a few hours which if it`s delayed enough, could keep the
storms from becoming too severe. The HRRR is suggesting this
scenario with very little additional convection developing between
now and 7 pm but convection increasing quickly in coverage and
intensity after the 7pm hour. Regardless, the closer we get to
midnight, we should be seeing scattered to numerous showers and
thunderstorms north of the I-20 Corridor with this convection
making quick progress towards the I-20 corridor by sunrise Monday
Morning. Not going to say we will not see any severe convection
overnight but if we do see the delay in redevelopment later this
afternoon/evening, it mighty curtail the severity of the storms
somewhat.
The front should be near or just north of the I-20 Corridor by
sunrise and will be very slow to get out of our southern zones
during the daytime hours on Monday, perhaps not pushing completely
through our region until Monday Night. The slower frontal
progression will result in a slower progression of milder/drier
air into the region from the northeast but that atmosphere will
eventually spill into our region during the day Tuesday.
Beyond Tuesday and through the remainder of the upcoming work
week, we begin looking in the Gulf for a increase in tropical
moisture from the south and east. This increase in moisture will
begin first of all from a pinched off part of a longwave trough
which should remain anchored across the West Central and North
Central Gulf through at least Tuesday. Its the interaction between
this upper trough (non-tropical) and possible tropical development
somewhere near the Yucatan Peninsula that has been giving the
medium range progs fits over the last several days and today is no
different. Solutions range from steering a tropical system nearly
due westward into the Bay of Campeche next week to lifting a weak
tropical low north northeast from the Yucatan towards the Fla
Pnhdl. Other solutions want to bring a weak tropical low somewhere
near the S La coast or SE Tx coast. Have decided to handle this
with a gradual increase in pops beginning late on Wed and
continuing this trend through the end of the upcoming work week.
Needless to say this could change significantly once the medium
range progs begin to lock onto a solution but believe we need
something to develop first near the Yucatan which is no guarantee
given the strong upper level shear in place through early next
week.
Prelims to follow...13.
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 76 86 70 92 / 60 60 10 10
MLU 75 85 69 90 / 40 60 10 10
DEQ 67 87 63 92 / 60 20 10 10
TXK 70 86 67 92 / 60 30 10 10
ELD 70 85 66 91 / 60 40 10 10
TYR 75 87 71 93 / 60 50 10 10
GGG 76 86 70 93 / 60 50 10 10
LFK 76 91 73 93 / 20 40 20 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
29/09/13
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Monday)
Issued at 256 PM CDT Sun Jun 18 2017
Upper level ridging will build across the Desert Southwest on the
backside of our departing Northern Plains trough that helped fuel an
active weather pattern over the last few days. This will keep NE
Kansas under a dry and seasonal weather pattern for the beginning
of the work week. Surface high pressure over eastern Kansas will
meander over NE Oklahoma/SE Kansas through the day tomorrow, keeping
a light westerly flow over much of the area. We will see highs in
the mid 80s tomorrow, with increasing return flow possibly pushing
temps a few degrees higher west of Manhattan.
A mid-level cloud shield over western SD and SE Montana will slide
southeast into NE Kansas with the H500 flow tonight and tomorrow.
The RAP and HRRR in particular develop precip with this elevated
feature overnight. Synoptic support is marginal at best with rising
heights aloft and Td depressions near 20 C in the BL beneath the
thin moisture plume. Thus am expecting most if not all of the precip
to fall from this band as virga. As the cloud shield mixes out
during the day, steepening mid-level lapse rates may yield a few
spotty mid-afternoon showers, though the CAPE profiles are quite
short and barely reach the freezing level before encountering a
500mb cap. Did not raise POPs to mentionable levels quite yet given
the lack of CAM consistency in these showers developing (the NAM is
the most bullish).
.LONG TERM...(Monday night through Sunday)
Issued at 256 PM CDT Sun Jun 18 2017
The Monday night and Tuesday periods appear to be the most likely to
be dry at this point. Northwest flow continues aloft with one area
of weak surface high pressure moving off Monday night and a weak
boundary sinking toward the area as an upper wave rotates around the
eastern Canadian upper low. Increasing westerlies over the northern
Plains keeps this boundary from making too much progress into the
state with little if any instability or convergence to keep daytime
precip in check. West to southwest low-level flow allows for a
warmer day with highs around 90.
Models are similar in shallow mid-level isentropic upglide
developing Tuesday night into early Wednesday ahead of the next
shortwave in the northern Plains but differ on moisture
availability. Will keep precip chances low at this point but some
scattered storms seem possible in the overnight. This wave brings a
weak cold front into south central Nebraska in the late afternoon
Wednesday with continued low-level theta advection ahead of it to
create a narrow band of ML CAPE values above 1000 J/kg with CIN less
than 60 J/kg ahead of it. Could see convection fire there in late
afternoon and translate east and south in the nighttime as 850mb
winds increase to around 45 knots. Afternoon temps bump up a bit
more especially in the west with gusty south-southwest winds
returning.
The Thursday into Saturday periods look to bring a few more waves
across the northern states, with intensity increasing with time as
the upper flow amplifies downstream of West Coast ridging. This
brings several opportunities for convection, though timing of the
best chances is very difficult at this range. There is good
agreement with the final trough bringing cooler and drier conditions
by Sunday. The highest temps into the weekend should occur Wednesday
and Thursday with heat indices again nearing 100 degrees.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 616 PM CDT Sun Jun 18 2017
VFR conditions are expected throughout the period. Winds will be
light and variable overnight prevailing from the WSW after 16Z.
There is a chance for some light showers to move across far
northeast Kansas in the very early morning, but it looks like any
precipitation will stay north and east of the terminals.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Skow
LONG TERM...65
AVIATION...Heller
Area Forecast Discussion
National Weather Service Tulsa OK
937 PM CDT Sun Jun 18 2017
.DISCUSSION...
Narrow band of showers and thunderstorms has remained persistent
through the afternoon and evening roughly along the Interstate 40
corridor. The latest HRRR runs suggest that this band will finally
start shifting south over the next few hours, with any remaining
precipitation confined to far southeast Oklahoma by morning. A few
strong storms remain possible overnight, with the potential for
some marginally severe hail, especially later near the Red River.
Have updated pops and sky cover for current trends, with the rest
of the forecast looking good at this time. Update on the way.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...11
LONG TERM....05
PLATE