Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/15/19
Area Forecast Discussion
National Weather Service La Crosse WI
949 PM CDT Sat Sep 14 2019
.SHORT TERM...(This evening through Sunday)
Issued at 245 PM CDT Sat Sep 14 2019
At 2 PM, skies were partly to mostly cloudy across the Upper
Mississippi River Valley. Scattered showers and isolated storms
have developed along and north of the Interstate 90 corridor. The
most robust convection was north of the Twin Cities. This latter
precipitation is located on the nose of the 850 mb jet. This jet
is bringing an increase in the moisture and instability ahead of
a shortwave trough over northwest Minnesota.
Additional storms were located across central Iowa. This is
associated with a MCV that developed overnight in eastern
Nebraska. This convection with this system will likely remain
south of the area. Temperatures were in the mid and upper 60s
north of Interstate 94 and in the 70s elsewhere.
For this evening, the 14.12z models are in good agreement that
the nose of the 850 mb jet will move into the Upper Mississippi
Valley. As this occurs, the 0-1km ML CAPES will climb up into 1500
to 2500 J/kg. Soundings continue to suggest that any showers and
storms will be elevated. The 1-7 km shear is very marginal for the
potential development of elevated supercells. The main threat
would be gusty winds and hail. With precipitable water values
between 1.3 and 1.8 inches, these storms will be efficient rain
producers.
The CAMs are really struggling with the development and
the placement of showers and storms this afternoon, so confidence
is not extremely high on how this is exactly going to play out
this evening. Overall, the experimental ESRL HRRR seems to be
handling the precipitation the best at the this time, so trended
the PoPs toward it. It would suggest the current convection north
of I-94 would move east across Clark and Taylor counties early
this evening. Additional convection would then develop along and
south of the Interstate 90 corridor during the mid to late
evening.
For overnight, the nose of the 850 mb jet will veer and move east
of the area. As this occurs, expect the showers and storms to
progressively move south and east out of our area. With this area
being so wet, it would not take much rainfall to cause additional
flooding, so kept the Flash Flood going. Low temperatures tonight
will range from the mid 50s to mid 60s.
On Sunday, high pressure will gradually build across the region.
Skies will gradually clear from the west. High temperatures will
range from the mid 70s to mid 80s.
.LONG TERM...(Sunday night through Saturday)
Issued at 245 PM CDT Sat Sep 14 2019
From Monday into Tuesday night, temperatures look to be well above
normal. 850 mb temperatures are running 1 to 2 standard
deviations above normal. Due to this, went a couple of degrees
above the MOS.
From Tuesday into Wednesday, there continues to a lot of
uncertainty on the eastern extent of a mesoscale convective
complex. The GFS would move it through our area. The ECMWF would
move it northwest of our area from Tuesday night into Wednesday.
Meanwhile, the Canadian keeps much of its precipitation north of
Interstate 90. Due to these uncertainties, made little change to
the NBM precipitation chances.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 949 PM CDT Sat Sep 14 2019
Main aviation concerns are on scattered showers and storms tonight
and MVFR to IFR stratus late tonight into Sunday morning.
Scattered showers and storms will move across the area tonight
with most of this activity staying south of the TAF sites. Then
guidance is suggesting low stratus develops across the area mainly
after 09Z. Ceilings are expected to fall to around 600 ft at KRST
by 11Z and to around 1500 ft at KLSE around 11Z. High pressure
then builds into the area late Sunday morning into Sunday
afternoon with a return to VFR conditions.
&&
.HYDROLOGY...Tonight
Issued at 354 PM CDT Sat Sep 14 2019
Moderate to strong 850 mb moisture convergence will move into the
area this evening and then move quickly out of the area between
15.09z and 15.12z. With preciptable water values of 1.3 to 1.8
inches, these storms will be capable of producing heavy rain.
Rainfall amounts will range from a half to 1 inch, but repeat
thunderstorms over localized areas could produce higher amounts.
With the recent rainfall, soils are saturated, and creeks and rivers
are already running higher than normal. This means it will take less
rainfall to cause mudslides and flooding.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Flash Flood Watch until 7 AM CDT Sunday for WIZ053>055-061.
MN...Flash Flood Watch until 7 AM CDT Sunday for MNZ086-087-094>096.
IA...Flash Flood Watch until 7 AM CDT Sunday for IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...Boyne
LONG TERM...Boyne
AVIATION...Wetenkamp
HYDROLOGY...Boyne
Area Forecast Discussion
National Weather Service Birmingham AL
613 PM CDT Sat Sep 14 2019
.UPDATE...
For 00Z Aviation.
&&
.SHORT TERM...
/Updated at 0145 PM CDT Sat Sep 14 2019/
Thus far, temperatures have remained a little more tame as compared
to yesterday. (We ended up breaking record highs at all four climate
sites as a result.) Wouldn`t expect to approach the century mark
again today as subsidence & dry air isn`t as prevalent, though will
be quite warm regardless with a run for low to mid 90s currently
ongoing. Our RADAR & satellite trends have suggested that cumulus
fields are showing a little more coverage/vertical growth with
further development expected in the coming hours. Expecting the
greatest activity along the I-20/59 corridors, & into the
northeast, where best PWs are available (~1.8" as suggested by
latest RAP mesoanalysis) as well as proximity to a confluent axis
noted in the 850-700 mb layer. Evaluation of the 12 Z RAOB earlier
this morning did suggest that a few thunderstorms could produce
localized gusty winds, though the overall microburst threat
remains below a confidence threshold such that mention in the HWO
was not needed.
Nonetheless, this update yielded PoPs generally similar to the
previous forecast cycle with only minor tweaks made to account for
trends in the latest HREF means. Have maintained chance PoPs in a
northeast to southwest fashion through the I-20/59 corridors, with a
gradual decrease in coverage & intensity towards 9 PM as activity
moves southwestward. Outside of any rainfall through this evening, &
a stray shower or thunderstorm tomorrow afternoon, rain chances look
very low through the next several days as the synoptic pattern
suggests deep-layer ridging & above average temperatures to
unfortunately continue.
40/Sizemore
.LONG TERM...
/Updated at 0401 AM CDT Sat Sep 14 2019/
Sunday through Friday.
With Tropical Storm Humberto located to the east of Florida on
Sunday, Alabama will be on the drier side of the storm. However, a
stray shower or storm cannot be ruled out as a narrow axis of
enhanced moisture lingers along and south of I-59.
Drier air will wrap around the west side of Humberto on Monday and
Tuesday as subsidence increases across the region. Temperatures
should soar back toward the 100 degree mark with the forecast area
in the grips of an intensifying drought. Some relief may start to
show up across our eastern counties on Wednesday with models
indicating a wedge of high pressure along and east of the
Appalachians. After one last day of upper 90s in our western
counties on Wednesday, afternoon highs for Thursday and Friday
should be several degrees lower. Unfortunately, there is still no
rain in sight for the extended part of the forecast.
87/Grantham
&&
.AVIATION...
00Z TAF Discussion.
Isold showers and tstms will continue across central Alabama thru
02z, possibly impacting KTCL and KMGM. VFR conds will prevail thru
the period with no cig or vsby issues outside convective areas.
Thunderstorm chances less than 20 percent Sunday afternoon, and
did not include any diurnal storms beyond 18z.
58/rose
&&
.FIRE WEATHER...
Isolated to scattered showers and storms remain possible through
this evening before drier conditions return to Central Alabama. Best
rain chances through tonight will be across the north. Afternoon RH
values remain above 40 percent Sunday. Lower humidity and hotter
conditions should return for Monday and Tuesday. KBDI values will
remain elevated due to ongoing drought conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 68 94 65 97 66 / 30 10 0 0 0
Anniston 69 95 67 97 67 / 20 10 0 0 0
Birmingham 72 95 70 97 70 / 30 10 0 0 0
Tuscaloosa 73 95 70 97 70 / 30 10 0 0 0
Calera 71 95 68 97 68 / 20 10 0 0 0
Auburn 70 92 70 94 68 / 10 10 0 0 0
Montgomery 71 95 71 97 69 / 10 10 0 0 0
Troy 70 94 70 96 68 / 10 10 0 10 0
&&
.BMX WATCHES/WARNINGS/ADVISORIES/...
None.
&&
$$
Area Forecast Discussion
National Weather Service Quad Cities IA IL
621 PM CDT Sat Sep 14 2019
.UPDATE...
Issued at 614 PM CDT Sat Sep 14 2019
All our focus will be on the onset of the storms from central Iowa
later this evening in the west/northwest. On the latest RAP data
on SPC`s mesopage, we still see a cut off MUCAPE to nil over
eastern Iowa, thus, despite the storms close proximity to eastern
Iowa, I don`t expect a rapid intensification, nor widespread
development of storms into our area quite yet. Later tonight, the
storms should expand into an MCS with heavy rain over our area,
which still in somewhat in question on how far north or south this
tracks.
&&
.SYNOPSIS...
Issued at 312 PM CDT Sat Sep 14 2019
18Z surface data has a weak warm front running from eastern Iowa
back into the eastern Dakotas. Dew points were in the 50s across
the Great Lakes with 60s and 70s from the Mississippi Valley into
the Plains.
&&
.SHORT TERM...(This Evening through Sunday)
ISSUED AT 312 PM CDT Sat Sep 14 2019
Headline changes...the flash flood watch for Jo Daviess,
Stephenson and Carroll counties has been extended until 10 AM
Sunday morning.
Through late this afternoon...
A persistent decaying storm complex across Iowa will likely push
sprinkles or some isolated showers south of I-80 and north of
highway 34 through late afternoon in eastern Iowa.
Tonight and Sunday...
The persistent complex across Iowa today raises questions as to how
storms will develop and evolve tonight.
Two scenarios are possible tonight. What is common between either
scenario is high moisture levels, unstable air aloft and forcing
from a passing upper level disturbance that will result in heavy
rainfall.
Scenario 1 involves new storm initiation along the IA/MN border
during the evening that moves southeast overnight and exits the area
late Sunday morning.
If this scenario occurs then the internal signal points to the
heaviest rainfall occurring between highway 20 and highway 30
generally north of an Independence, IA to Sterling, IL line.
Scenario 1 is what the current forecast is based upon.
Scenario 2 would have new convection develop with the remnants of
the current system across Iowa. If this occurs then the heavier
rainfall would occur across southeast Iowa into west central
Illinois.
If scenario 2 occurs then the overall forecast message would need to
be changed considerably.
.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 312 PM CDT Sat Sep 14 2019
tarting the period off with adding some precipitation chances to
the southern areas for Sunday evening. The front will be situated
across the far southern part of the forecast area and with some
convergence and moisture pooling along the front, felt there is
enough of a chance for showers and thunderstorms to add a slight
chance in for the evening hours.
High pressure builds in at the surface through the day Monday with
return floe being seen over the plains into Western Iowa as the
upper level ridge is centered up and down the Mississippi River
valley. The setup looks good for patchy to even areas of fog with
good moisture at the surface under the inversion and mostly clear
skies Sunday night into Monday. The areas with the weakest low level
flow to support fog development will be across the northeast
quadrant of the forecast area so have limited the mention of fog do
those areas.
Temperatures on Monday will be a bit warmer than on Sunday and will
be well above normal in the 80s. Think that even if fog does form
and holds on longer into the morning, temperatures should recover
rather quickly to get those areas into the 80s.
The big story for the week will be hot and humid. The upper level
ridge sits in place through the week. Temperatures Monday through
Wednesday will be warmest with highs in the mid to upper 80s and
with dewpoints in the upper 60s to low 70s, it will be quite
uncomfortable for this time of year.
A few shortwave troughs will move through the flow to provide
chances for thunderstorms beginning on Wednesday and continuing
through the week. The chances for widespread thunderstorms is
highest Wednesday night as the primary wave of shortwave energy
moves across the area. Timing could change this to earlier or
later, which will need to be watched for any stronger storm
potential or heavy rain/flooding potential. Moving through the
remainder of the week, there will be minor weak shortwave energy
moving through the southwest flow across our area periodically,
but timing those pieces of energy is not anything that can be done
at this point with high confidence. Also, with high dewpoints
providing decent instability will likely lead to at least some
daily diurnal convection. Therefore thunderstorm chances are in
the forecast through all periods.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 614 PM CDT Sat Sep 14 2019
Storms will move east through eastern Iowa and northern Illinois
tonight as a warm front lifts over the region. Heavy rain, small
hail and gusty winds can be expected as storms push through. I
have conditions mainly VFR as far as cloud bases are concerned,
but visibility may drop to under 1 mile in storms. The
thunderstorms will exit the region in the 12Z to 15Z window Sunday
morning, and a VFR dry day should develop by mid morning.
&&
.HYDROLOGY...
Issued at 1129 AM CDT Sat Sep 14 2019
Routed water moving through the river systems along with
additional heavy rain potential tonight is causing forecast rises,
many within bank rises, across the area.
The hardest hit local basins have been the Pecatonica and Rock
River basins and we are getting a better handle on the flows from
rains that already fell, however there does remain a bit of
uncertainty on how high the crests will be. The Pecatonica in
Freeport is cresting currently and will fall less than a foot
before starting to go up again as more water moves down from
upstream.
On the Rock, the forecast for the gage at Como has gone down this
morning and the rate of rise has slowed, giving less confidence
that the river will hit the flood stage of 12.5 ft even though
it`s only a half foot from that level currently. Because of this,
opted to hold onto the flood watch and will re-evaluate this
afternoon. Downstream at Joslin, it may be noticed that the
hydrograph is now showing the river to rise to 14.1 feet. Think
the rise is going to be very near 14 ft, but don`t have enough
confidence that it will reach or exceed 14 ft to put out a new
flood warning for moderate flooding yet. Will continue to monitor.
There is a chance for heavy rains tonight, if heavier rains fall
than is expected, additional river flooding could occur.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flash Flood Watch through Sunday morning for Buchanan-Delaware-
Dubuque-Jackson-Jones.
IL...Flash Flood Watch through Sunday morning for Carroll-Jo Daviess-
Stephenson.
MO...NONE.
&&
$$
UPDATE...Ervin
SYNOPSIS...08
SHORT TERM...08
LONG TERM...Brooks
AVIATION...Ervin
Area Forecast Discussion
National Weather Service Fort Worth TX
627 PM CDT Sat Sep 14 2019
.AVIATION...
/00z TAFs/
Concerns: None major; VFR with east winds prevailing. Possible
SHRA/TS tomorrow afternoon across central and southern Texas.
VFR will prevail through the entire TAF valid period. High
pressure across the region will keep chances for precipitation
low, though a few showers and isolated thunderstorms may attempt
to develop east and south of D10 airspace tomorrow afternoon.
There is a small chance of a shower developing in the vicinity of
the Waco terminal after 19-20Z, however the confidence of this is
too low to include VCSH/VCTS in the TAF ATTM.
Light east to southeast winds under 10 knots should persist
through the period with diurnal CU between 060-080 tomorrow
afternoon.
Bonnette
&&
.SHORT TERM.../Issued 1251 PM CDT Sat Sep 14 2019/
/Through Sunday Evening/
Tranquil and unseasonably warm weather is anticipated over the
next 24 to 30 hours across North and Central Texas. There is a low
potential for a few showers across East and North Texas, but this
threat is far too low to include in the forecast.
Ridging continues to dominate the weather across the Southern
Plains early this afternoon. Surface high pressure was noted
across parts of southeast Oklahoma at this hour, and this has
resulted in an east to northeast flow regime across North and
Central Texas. This afternoon, temperatures will climb into the
mid 90s as boundary layer mixing continues. Some hi-res guidance
does imply the potential for a few showers, but the 12 UTC FWD
RAOB and RAP forecast soundings suggest that this potential is not
worthy of a mention in the forecast.
Tonight, clouds will diminish and light winds are forecast. This
should foster a decent radiational cooling episode with overnight
lows dipping into the 60s and 70s. Lows across the more urbanized
areas may remain in the mid 70s. Overall, it should be a pretty
pleasant overnight period. Sunday will feature another day of
quiet weather, though low level moisture may increase some as an
easterly wave currently across the Central Gulf of Mexico
continues to churn westward. The potential for showers/storms
still appears low, but there could be an increase in tropospheric
moisture (particularly across East Texas), and this may result in
a few more clouds. Regardless, it`s likely that temperatures will
still climb into the mid to upper 90s with the warmest conditions
across the Big Country (generally west of US HWY 281).
Bain
&&
.LONG TERM... /Issued 320 PM CDT Sat Sep 14 2019/
/Sunday Night through Saturday/
From Sunday Night through Tuesday, the upper level ridge will
remain centered to our northeast with an upper level trough
across the western half of the CONUS. In the Gulf of Mexico, a
weak upper level disturbance will slowly meander along the Texas
Coast, and then will likely dissipate around the middle of next
week. However, the presence of this upper level disturbance will
have transported higher moisture into the region with PWAT values
slightly above normal for this time of year. This will yield some
rain chances across mainly Central Texas Monday through Thursday,
but some isolated or scattered showers and/or storms may creep
into North Texas, too.
Rain chances Monday through Thursday range from 20-30 percent
across parts of North Texas, to 40-60 percent across parts of
Central Texas. The reason for the increase in rain chances is
largely do to increased consistency and confidence in rain
reaching Central Texas. The coverage should be scattered for the
most part, with possible small clusters occurring at times. This
does not mean everyone will see rain, but some locations in
Central Texas could receive half an inch or more of rain this
week. Widespread severe weather is not expected but gusty winds,
periods of heavy rainfall and possibly even some small hail will
be possible.
Temperatures will continue to be warm next week, but occasional
winds around 10 mph will provide some relief. Generally look for
highs in the lower to mid 90s with overnight lows in the upper 60s
to mid 70s. Heat index values will approach 100 degrees at times
next week, but are currently not expected to go much higher than
that. We may see some slightly cooler daytime temperatures by the
end of the week.
The upper level ridge will continue to largely dominate our
sensible weather heading into next weekend, while the principal
storm track remains well to our north. Remnants of the weak
disturbance that dissipates along the Texas Coast may be drawn
north late in the week, allowing for scattered showers and storms
to spread a little farther north. Widespread rain is still not
expected, and unfortunately not everyone will see rain this week.
JLDunn
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 74 98 75 97 76 / 5 0 0 0 5
Waco 71 99 74 97 74 / 5 0 5 10 10
Paris 71 96 73 94 72 / 0 0 0 0 0
Denton 73 97 73 96 74 / 5 0 0 0 0
McKinney 73 97 73 96 74 / 5 0 0 0 0
Dallas 77 99 76 97 77 / 5 0 0 0 5
Terrell 73 96 75 97 74 / 5 0 0 0 5
Corsicana 72 96 73 96 73 / 5 0 5 5 5
Temple 71 98 73 96 73 / 5 0 5 10 10
Mineral Wells 70 98 71 95 71 / 5 0 0 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
06/22
Area Forecast Discussion
National Weather Service Goodland KS
515 PM MDT Sat Sep 14 2019
.SHORT TERM...(This afternoon through Sunday Night)
Issued at 1245 PM MDT Sat Sep 14 2019
Today... A slight chance for showers and thunderstorms will be
possible this afternoon and evening mainly along and east of a line
from Leoti to Gove to Hill City, Kansas. Forecaster confidence
remains low on the potential for any storms to develop. However, if
storms do develop, there is a chance that those storms could be
severe with the greatest weather threat being damaging wind gusts up
to 60 mph. With an upper-level trough progressing eastward through
the Central Plains today, there could be some marginal support for
ascent more towards central Kansas. That flow pattern paired with
moderate instability with HRRR forecast CAPE values around 1000 to
1500 J/kg means that a small possibility for severe weather will be
present this afternoon and evening. The timing for any showers and
thunderstorms would be between 4 PM and 10 PM CDT. Afternoon highs
for Saturday will generally be in the upper 80s to lower 90s. Winds
will be fairly light and variable for this time of year except for
the region where showers and storms may be possible where some
southwesterly winds gusting to 20 kts will be possible through this
evening.
Tonight... Light and variable winds with clearing skies are expected
tonight as the aforementioned upper-level trough moves out of the
forecast area. Overnight lows tonight will be similar to the
previous night with temperatures down to the lower 50s expected in
Yuma County, Colorado increasing southeastward with lows in the
middle 60s in Graham County, Kansas. With light winds, clear skies,
and relatively moist air in place tonight, some patchy fog may be
possible late tonight and into the early morning hours Sunday. The
potential for fog will generally be limited to east of US Hwy 83
where there will be lighter winds and will be patchy at best.
Sunday... Any fog which forms early Sunday morning will dissipate
shortly after sunrise. Breezier southerly surface winds are expected
tomorrow from the late morning through the overnight hours as a
surface trough moves through the forecast area. Wind gusts will
generally be up to 20 to 25 kts across the Tri-State area. Mostly
clear skies are expected Sunday morning, however some partly cloudy
skies are expected to move in from the west Sunday afternoon and
persist into the overnight hours. No precipitation is expected
Sunday at this time. Generally, Sunday will be a pleasant and warm
early fall day with afternoon highs in the lower 90s.
Sunday Night... Partly cloudy skies will stick around through the
overnight hours Sunday and into early Monday morning, as well as
breezy southerly surface winds with gusts up to 20 to 25 kts. No
precipitation or fog is currently expected overnight Sunday as
slightly lower humidity values are forecast for that time period.
Overnight lows will only get down to the lower 60s farther northwest
and the upper 60s farther southeast with the forecast area.
.LONG TERM...(Monday through Saturday)
Issued at 151 PM MDT Sat Sep 14 2019
Forecast concern will be winds Monday and chances of precipitation
through the period. The rainfall forecast will be more difficult
than normal due to model differences on mid/upper level features
plus surface boundary positions which will be near or over the area.
Satellite showing an amplified patter across the Pacific which then
transitions to a more zonal/broad across the country.
Monday/Monday night...Strong south to southwest flow aloft is in
place. Tight pressure gradient along with 3 hour pressure falls
nearing 5 mb will cause windy conditions. After collaboration with
neighbors and loaded in Consmos for the winds.
Models show a rather strong system approaching/moving through the
area from the southwest. Also some weak jet lift in place. Some
surface lift provided with a surface trough/dryline near the
Colorado/Kansas border. Mid level moisture is available with 700 to
500 mb temperatures not high enough to cap the air mass as
surface/layer cinh also show. There is an adequate amount of Cape.
Storms that form will be high based but based on the above believe
there is enough there for a few thunderstorms to form. Models show
large amounts of Dcape and combined with the strong surface winds,
strong and gusty outflow winds will be a big threat. The blend gave
me no pops but did raise them to slight chance.
Tuesday/Tuesday night...Models in general are in good agreement with
a negative tilt shortwave system from the northern Great Basin into
the Pacific Northwest. However, they differ on how fast and strong
this system is. To start out the Ecmwf and Canadian are much
slower/stronger/further south than the more open Gfs, and the
fastest Nam. This trend continues through the period with the Ecmwf
the slowest, the Canadian in the middle, and then the Gfs.
Of course the Gfs is more in line with its ensembles even though it
is still more amplified than them. Main lift looks further north
than the day before but the northern stream shortwave will push a
cold front to help with the lift. Like the small forecast blend pops.
Wednesday through Saturday...Models keep the same general pattern of
troughiness in the western portion of the country. However by the
end of this period the models are not in strong agreement. Per the
amplified pattern in place and the teleconnections mentioned in the
PMDEPD, would support the more amplified solutions.
Considering the model differences and surface boundaries around, it
is hard to make a case to change the pops. Although there is
potential for pops to be higher. So left the pops alone in this
period. Also left the temperatures alone, despite a couple of
frontal passages, the air mass does not look likes it changes much.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 515 PM MDT Sat Sep 14 2019
For KGLD and KMCK, vfr conditions through the period. Light and
variable winds at taf issuance will continue overnight then
increase from the south (KGLD) with gusts around 25kts expected
Sunday afternoon. For KMCK winds become southeast 8-11kts after
18z Sunday.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...PATTON
LONG TERM...BULLER
AVIATION...99
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
628 PM CDT Sat Sep 14 2019
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...
00Z issuance...VFR conditions the next 24 hrs. A large upper
level low pressure system over the Gulf favors a continuation in
scattered to broken high level cirrus streaming westward over the
central Gulf coast. A mostly light northeast wind at MOB and BFM
continues tonight while at PNS, light southeast winds become
northeast overnight. A few shra, moving westward this evening
over the interior, expected to stay north of the terminals. /10
.PREV DISCUSSION... /issued 359 PM CDT Sat Sep 14 2019/
NEAR TERM /Now Through Sunday/...An easterly low to mid level flow
pattern will continue across the central Gulf Coast region tonight
and Sunday on the southern periphery of a deep layer ridge of high
pressure extending eastward across the Tennessee Valley and the
Eastern Seaboard. Moisture will remain a little more enhanced over
interior portions of southwest AL and southeast MS this afternoon,
where precipitable water values will range between 1.6" and 1.8" per
the latest RAP model guidance. A weak impulse moving west-
southwestward toward central and interior southwest AL may aid in
the development of isolated showers or thunderstorms over interior
portions of the forecast area late this afternoon into early this
evening, and will maintain a ~15% POP over these areas through early
evening. A brief shower or storm may also develop along the
seabreeze near the coast through around 7 PM or so. Clouds gradually
decrease late tonight and overnight lows should range from around 70
degrees to the lower 70s inland, with mid to upper 70s along the
immediate coast. Upper ridging will tend to build farther into
central portions of MS/AL on Sunday. A more subsident airmass
underneath this feature may tend to preclude convective development,
although an isolated shower or storm cannot be entirely ruled out,
especially near the coast along the seabreeze. Highs should range in
the lower to mid 90s. /21
SHORT TERM /Sunday night Through Tuesday night/...A large upper
ridge extending from the southeast states to across the Plains
remains in place over the region while the northern portion
advances into the eastern states. Tropical Storm Humberto will be
initially located approximately 225 miles east of Jacksonville,
Florida then continues further off into the western Atlantic
through Tuesday night. A surface ridge remains in place over the
eastern states through the period, which along with the western
fringe of Humberto`s circulation will promote a light northerly
surface flow over the area. Subsidence associated with the upper
ridge will maintain dry conditions over the forecast area and also
contribute to above seasonable daytime temperatures. Highs will
be mostly in the mid 90s on Monday followed by mid to upper 90s
on Tuesday. Lows will generally range from the lower 70s inland
to the mid 70s at the coast. A low risk of rip currents is
expected through the period. /29
LONG TERM /Wednesday Through Saturday/...An upper ridge will be
in place over the eastern states and into the south central states
through Saturday. A surface ridge strengthens from the mid
Atlantic coast into the southeast states through the period, which
causes a transition from a light northerly surface flow on
Wednesday to an easterly flow on Thursday. This is what`s known as
a back-door cold front, but despite the name only brings somewhat
of a respite to the hot temperatures. This feature will be
sufficient to produce isolated to possibly scattered showers and
storms over much of the area on Thursday, but otherwise dry
conditions prevail. Highs on Wednesday will be in the mid to upper
90s then highs each following day will be in the lower 90s. Lows
Wednesday night range from the lower 70s inland to the mid 70s at
the coast, then the following nights will see mid to upper 60s
inland ranging to the lower 70s near the coast. /29
MARINE...A ridge of high pressure will extend southwestward along
the northern Gulf through the remainder of the weekend, resulting in
a continued light to moderate easterly wind flow over the marine
area. Small craft may need to exercise caution again offshore late
tonight into Sunday. A light to occasionally moderate east to
northeast flow will prevail at night and early in the morning Monday
before becoming light onshore by Monday afternoon. Seas remain
elevated between 2-4 feet near shore and 3-5 feet offshore through
Sunday, before gradually subsiding into early next week. /21
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk until 5 AM CDT Sunday for ALZ265-266.
FL...High Rip Current Risk until 5 AM CDT Sunday for FLZ202-204-206.
MS...None.
GM...None.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion
National Weather Service Marquette MI
655 PM EDT Sat Sep 14 2019
.SHORT TERM...(This evening through Sunday)
Issued at 404 PM EDT SAT SEP 14 2019
Water vapor imagery and RAP analysis show the shortwave that brought
the widespread rain to the area late Thu into early Fri lifting into
Quebec. In its wake, flow has become more zonal across the northern
CONUS. In this flow, a well-defined shortwave is located vcnty of
the ND/MN/Manitoba border. This wave will be the next feature of
interest as it moves across the area late tonight/early Sun. Farther
s, rather strong isentropic ascent/theta-e adv was driving another
area of shra/tsra over IA. Closer to home, sunny skies have mostly
been the rule this aftn across the fcst area. After a cloudy morning
over the far eastern fcst area, clouds have now cleared out. Breezy
winds are also beginning to settle down as pres gradient relaxes
with arriving sfc high pres ridge.
Aformentioned shortwave approaching the area tonight will make for
an interesting and challenging fcst. In response to the shortwave,
the rather strong isentropic ascent/theta-e adv driving convection
across IA will shift ne toward Upper MI, though in a somewhat
weakened state. This ne advancing isentropic ascent/theta-e adv is
already causing a new area of shra/tsra development btwn KMPX and
KDLH. Meanwhile, small upper jet streak associated with the
shortwave will shift across Lake Superior while the leading edge of
another jet streak translates from ND across MN to northern
WI/western Upper MI by 12z Sun. Result is a coupling of the 2 jets
(right entrance of one and left exit of the other) to enhance upper
divergence over ne WI/Upper MI. Combined with advection of elevated
instability into the fcst area of at least a few hundred j/kg, looks
like a good setup for shra and some tsra to spread/develop across
Upper MI tonight, especially central and eastern Upper MI. Given the
forcing, wouldn`t be surprised if there are localized streaks of
fairly hvy pcpn with some of the tsra, similar to what the cams are
showing. If instability is on the higher end, NAM for example with
up to 1000j/kg of elevated instability advecting toward Upper MI,
estimated effective shear would be sufficient for a few organized
storms that would pose a hail risk.
Expect the shra/tsra to diminish w to e late tonight, leaving behind
abundant low clouds for much of Sun. There may be some fog and
patchy -dz during the morning, especially where light e to se winds
are upsloping. Weak nnw to sse oriented sfc trof will move across
the w half of Upper MI during the day on Sun. If there are
sufficient breaks in the clouds during the aftn to allow for a
little sfc based instability to develop, isold -shra may develop
vcnty of the trof.
.LONG TERM...(Sunday night through Saturday)
Issued at 414 PM EDT SAT SEP 14 2019
After feeling like September in August, the next week or so will
feel like August in September! Ridging will dominate most of the
long-term period around the Upper Great Lakes with anomalous warmth
as a result. There are a few rain chances this week but no
significant systems.
To start off Sunday night, surface high pressure will be overhead
which will lead to cool overnight lows - but not particularly cold
given warmer air advecting in aloft and NW cyclonic flow aloft both
contributing to lingering cloudiness. Have lows getting into the
mid to upper 40s west where more clearing is expected, and staying
above 50 everywhere else. The west is also most likely to see some
early morning ground fog, should any form. For now, have kept it all
patchy.
Despite some clouds around, the warming trend begins Monday. 12z 850
mb temps around 13-14 C, with additional warming during the day,
suggests that highs in the mid 70s to around 80 are possible Monday
even despite shallower mixing than we`d see in early-mid summer. The
GFS continues to resolve a ridge roller or similar feature Monday
night that triggers numerous showers, and the rest of the guidance
continues to buck that trend. Reluctantly drew in slight chance POPs
over the western arm of the lake and the Keweenaw but still not
really believing anyone will see rain Monday night.
The air aloft warms further on Tuesday. Depending on how many (if
any) lingering clouds, Tuesday could be even warmer with highs in
the low 80s west and central and mid to upper 70s east. With dew
points in the 60s too, it will actually feel somewhat uncomfortable
by Tuesday. The weather Tuesday night through Thursday then depends
on just how stubborn the ridge over us is. All of the models
indicate a weakness Tuesday night that mostly remains to our west
but could spark off a few showers and thunderstorms over the far
west. (The GFS breaks down the ridge quicker and soaks us Wednesday.
Once again, did not buy into that solution.) Eventually though the
ridge will weaken Thursday as a more potent mid-level short wave
lifts northeastward from the Northern Plains into northern Ontario.
It should drag a cold front across Upper Michigan Wednesday night or
Thursday, but how exact timing and just how strong remain uncertain
so mostly left NBM`s slight chance to chance POPs. Should be enough
CAPE for thunderstorms with this front.
High pressure builds in Friday as the upper-level ridge
restrengthens. Models split on how long that high persists into next
weekend so have left the NBM`s slight chance POPs in.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 655 PM EDT SAT SEP 14 2019
VFR conditions will prevail into the evening at all sites.
Disturbance moving into the Upper Great Lakes will spread sct shra
and a few tsra across Upper MI tonight. There is still some
uncertainty in where these shra will occur, so only VCSH was
included in the fcst. Right now, it appears KIWD and KSAW have the
better chc of being impacted. Later in the night into Sun morning,
expect a sharp drop in cigs with IFR developing at KSAW/KIWD and
MVFR at KCMX. Fog may also develop. IWD will go back to VFR late on
Sun while SAW stays down in IFR/LIFR while CMX will go to MVFR late.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 404 PM EDT SAT SEP 14 2019
After the recent windy conditions and gales on Lake Superior, a
quieter weather regime will mostly prevail for the next several
days. Winds are continuing to diminish w to e across Lake Superior
this aftn as sfc high pres ridge is moving into the Upper Lakes.
Winds across Lake Superior tonight are expected to be under 20kt,
though there may be some gusts to 20-25kt across central and eastern
Lake Superior late tonight/early Sun morning as a warm front
advances ne toward Upper MI. Winds will diminish to under 15kt Sun
aftn as pres gradient weakens. These lighter winds will then linger
into Mon. Expect winds under 20kt on Tue before an increase in winds
occurs on Wed ahead of an approaching cold front. Over the e half of
the lake, southerly winds gusts could increase to 25-30kt at high
obs platforms on Wed. Since cold front will weaken as it crosses
Lake Superior Wed night/Thu, winds will diminish heading into Thu.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Beach Hazards Statement until 8 PM EDT this evening for MIZ006.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...RJC
AVIATION...07
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Las Vegas NV
859 PM PDT Sat Sep 14 2019
.SYNOPSIS...Sunday will bring one more day of above normal
temperatures before a low pressure system dropping down from the
Pacific Northwest moves across the southern Sierra and Great Basin
on Monday bringing very windy conditions and significantly cooler
temperatures. Another weather system will follow a similar track and
bring more wind to the region Wednesday through Friday.
&&
.UPDATE...Another quite evening across the area thus far with warm
temperatures and light winds. Hires models have continued to show an
outflow boundary working its way into southern Mohave County this
evening from decaying thunderstorms over the FGZ/PSR CWAs. Evidence
of this is showing up in the 8 pm observation data where southeast
gusts up to 35 mph are being reported by a sensor on Highway 93 in
far southeast Mohave County. The HRRR forecasts these outflow winds
reaching into the Colorado River Valley later this evening and into
southern Clark County overnight. As the outflow boundary moved
across this sensor, temperatures dropped only about 3 degrees but
surface dewpoint temps rose from around 40 degrees into the upper
50s. RAP analysis shows a tongue of PWATs around an inch pushing
into far southern Mohave County but with limited instability. Radar
returns to this point have been weak but I can`t completely rule out
a light shower and/or a brief thunderstorm developing mainly along
the boundary as it rolls through. No updates were made to the
forecast for now.
&&
.PREVIOUS DISCUSSION...257 PM PDT...
.DISCUSSION...through next Saturday.
The main focus of the forecast through Monday evening is the wind
impacts expected from the incoming trough digging out of the Pacific
Northwest. The latest high res model wind fields indicate the
strongest belt of winds developing Monday afternoon and evening
across the southern Sierra and Inyo, Nye, Lincoln and northwest
Clark counties where gusts over 40 mph are likely. Even though
periods of downslope winds with gusts over 40 mph appear likely in
the southern Sierra and Owens Valley late Sunday afternoon through
Sunday night, the best potential for dangerously high winds gusting
over 60 mph will be Monday afternoon through early Monday evening
and a High Wind Watch has been issued to highlight this. The strong
winds, low relative humidity and dry fuels will create critical
fire weather conditions.
Winds are forecast to drop off fairly quickly Monday evening and
there is no indication of strong post frontal winds pushing into
southern Nevada since the upper level trough is forecast to lift
away across northeast Nevada and Northern Utah. Tuesday will provide
a brief break between systems before the next deep upper low is
projected to roll across the Great Basin Wednesday through Friday
providing another round of windy condition before lifting away to
the northeast by next weekend. Aside from the wind, this pattern
will keep temperatures subdued to near or slightly below normal.
A secondary concern exists over northwest Arizona where convection
this afternoon and evening around the central Arizona rim country is
expected to produce gusty winds which may push outflow and some
moisture toward the Colorado River Valley and up into central and
southern Mohave County tonight. This will lead to possible isolated
thunderstorms this evening over far southeast Mohave County near
Wikieup and Alamo Lake then chances for thunderstorms will exists
Sunday afternoon into Monday as somewhat moist and unstable air
holds over the eastern half of Mohave County.
&&
.FIRE WEATHER...A strong low pressure system will bring gusty
winds to Inyo County California beginning Sunday afternoon then
strong winds will spread across most of southern Nevada
Monday...leading to critical fire weather conditions. A Red Flag
Warning is in effect for Inyo County California zones from 3 PM
Sunday until 9 PM PDT Monday. High downslope winds gusting to at
least 60 mph will be possible along the eastern Sierra slopes and
adjacent areas of the Owens Valley early Monday afternoon through
early Monday evening. Southwest gusts over 35 mph will affect the
mountains of Death Valley National Park from Sunday afternoon
through Monday evening.
A Red Flag Warning is in effect for most southern Nevada zones from
11 AM Monday morning until 9 PM PDT Monday evening. A belt of strong
southwest winds gusting over 35 mph is forecast much of Nye,
northwest Clark and Lincoln counties from late Monday morning
through Monday evening.
The strong winds will be accompanied by minimum RH values in the
single digits to lower teens.
&&
.AVIATION...For McCarran...Typical light drainage winds expected
this evening, with light and variable winds for much of Sunday. Some
outflow from Arizona thunderstorms may push into the valley after
midnight tonight, but chances for this are decreasing. By Sunday
afternoon, a southerly push could advance across the valley, with
winds transitioning from light and variable to southerly around 8 to
12 kts. Southwest winds may begin increasing late in the evening
with stronger southwesterly winds for Monday. The primary hazards of
low-level wind shear and clear air turbulence look to be late Sunday
evening through Monday.
For the rest of southern Nevada, northwest Arizona and southeast
California...Generally light winds expected overnight for much of
the region. There remains an outside chance of gusty outflow winds
impacting areas southeast of Interstate 15 tonight. Expect southerly
winds to begin increasing across the region, especially the Owens
Valley tomorrow, bringing low-level wind shear and clear air
turbulence hazards.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Salmen
DISCUSSION/FIRE WEATHER...Adair
AVIATION..................Steele
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