Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/15/16
Area Forecast Discussion
National Weather Service La Crosse WI
615 PM CDT WED SEP 14 2016
.SHORT TERM...(Tonight through Thursday Night)
Issued at 248 PM CDT Wed Sep 14 2016
Surface to mid-level ridge of high pressure giving the area a
pleasant day. Scattered to broken stratocumulus were across central
WI...remnants of overnight Lake Superior/Michigan stratus.
Otherwise...mostly sunny elsewhere with temperatures as of 2 pm
ranging from the middle 60s to the lower 70s.
For tonight...surface high pressure centers itself across the Great
Lakes region with the ridge axis extending westward across our
area. This will provide for another quiet/cool night. Concerned
about stratocumulus advecting in here after midnight as surface to
1km winds turn to a more southeasterly direction. Various model RH
fields and NSSL WRF synthetic low cloud/fog imagery do indeed show
some stratocumulus moving in overnight. As such...have increasing
cloud cover after midnight mainly southwest of I-94. With lack of
clouds across the bog country of central WI...will likely see some
patchy fog as temperatures dip down into the lower/mid 40s. May also
see some river valley fog as well but not expecting it to be more
than patchy in nature. Lows away from the bog country expected to
fall off into the lower 50s.
For Thursday...will likely get most of the day in dry as high
pressure holds over the Great Lakes Region. Could see a few showers
and thunderstorms move into areas west of the Mississippi River
later in the afternoon as plume of 1.5-1.6 inch precipitable water
gets lifted ahead of ahead of an approaching mid-level wave. Showers
and thunderstorms then looking likely going into Thursday night as
broad 850mb moisture transport noses into the area in southwest
flow. Increasing cloud cover should hold high temperatures Thursday
in the low to middle 70s.
.LONG TERM...(Friday through Wednesday)
Issued at 248 PM CDT Wed Sep 14 2016
Vigorous mid-level trough pushes a cold front into the area Friday
afternoon. Main PV-advection tied to the trough rotates northeast
through northern MN/WI. Meanwhile...it appears convergence get
washed out along the surface cold frontal boundary across out area.
Still looks like ample moisture/cape for the front to work with
precipitable water values up in the 1.5-1.7 inch range. NAM showing
highest cape/shear values but looks a bit overdone compered to the
GFS/ECMWF. Needles to say...looks like showers and thunderstorms
will be scattered about but not anticipating anything severe at this
point. However...with abnormally high precipitable water values in
place...some storms will be capable of locally heavy rainfall.
Otherwise...Friday looks to be a rather humid/muggy with highs in
the 70s and dew points in the middle/upper 60s.
Bulk of showers/thunderstorms push east out of the area with the
front after midnight Friday night...leaving Saturday cooler/drier.
Sunday through Sunday night look dry as high pressure drifts across
the Upper Mississippi River Valley.
Latest GFS/ECMWF a bit at odds for Monday through Wednesday. ECMWF
would suggest warmer/dry conditions through the period with a broad
area of high pressure building over the central conus/ The GFS on
the otherhand shows a fairly high-zonal flow transitioning to
southwest flow aloft which then brings a couple troughs through the
area for on/off shower and thunderstorm chances. Will take the
consensus approach for now which yields 20-40 percent chance for
showers/storms.
Temperatures look to stay right around normal with highs in the 70s
and lows in the 50-60 degree range.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 615 PM CDT Wed Sep 14 2016
CU popped across southeast WI today, in response to a pool of low
level RH. NAM suggests this saturation would press west tonight as
winds become more southeasterly. This could manifest into mvfr cigs.
However, the GFS and RAP generally hold this potential across
eastern WI. Going to play the optimistic card and keep sky cover vfr
overnight.
If low stratus doesn`t move it, good radiational cooling and light
sfc winds suggest widespread river valley fog. A look at the
NAM/RAP/HRRR bufkit soundings for KLSE show increasing winds within
in a couple hundred feet of the sfc by 06z, persisting through 12z.
This usually holds any fog that forms in the Mississippi to the main
channel - not spreading across the airport. Will stay with BCFG for
a few hours for now, but see some potential for a stratus layer to
move in from the river...something like p6sm bcfg bkn003. Will have
to watch closely and amend if necessary.
Clouds will be on the increase from the west on Thu as a cold
front/low pressure system approach. Could see some -shra/ts chances
before 00z fri at KRST, but a better shot Thu night...so will hold
off on adding to the forecast for the moment.
&&
.ARX Watches/Warnings/Advisories...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....Rieck
Area Forecast Discussion
National Weather Service Bismarck ND
955 PM CDT Wed Sep 14 2016
.UPDATE...
Issued at 950 PM CDT Wed Sep 14 2016
Latest HRRR runs really muffle the leading convective system as
it moves into North Dakota around midnight tonight. The pops have
been adjusted accordingly reflecting the trend of delaying the
convection a bit. Did not want to throw out the whole current pop
forecast so blended with the pops towards morning. Overall small
changes.
UPDATE Issued at 623 PM CDT Wed Sep 14 2016
Based on the latest regional radar loops, the current forecast
that delays the onset of showers and thunderstorms across
southwest North Dakota until late this evening seems prudent.
Otherwise a well defined upper low in southeast Idaho on water
vapor imagery has a shortwave moving northeast into eastern
wyoming. This feature will move into southwest North Dakota
later tonight and will be the focus for widespread showers and
scattered thunderstorms mainly after midnight. Current forecast
looks good so far.
&&
.SHORT TERM...(Today through Friday afternoon)
Issued at 324 PM CDT Wed Sep 14 2016
Forecast highlights in the short term period will be showers and
thunderstorms developing late tonight, continuing Thursday and
Thursday night before ending Friday. A few stronger storms
Thursday aft/eve possible south central into the James River
Valley, along with the potential for excessive rainfall over much
of west/central ND Thursday & Thursday night will be the primary
focus.
Currently, short wave ridge extending into the Northern Plains
this afternoon results in a mostly clear sky and comfortable
temperatures in the 60s to lower 70s. High pressure which was over
the region yesterday now over the Great Lakes region resulting in
southerly return flow contributing to our warmer temperatures
(still cool) along with breezy southerly winds.
Deep area of low pressure now over the Intermountain West will
eject east-northeast into the Dakotas during the day on Thursday,
stalls then moves off to our east later in the day on Friday.
This feature will bring widespread showers and scattered
thunderstorms beginning tonight southwest, spreading north and
east across western and south central ND 06-12Z. For tomorrow,
narrow band of instability with MUCAPE forecast in the 1500-2500
J/kg range develops along to east of a surface trough across the
central Dakotas, over the south central and James River Valley
Thursday daytime, coinciding with marginal 0-6km shear values of
25-35KTs. Limiting factor on strong to possible severe convection
will be extensive clouds in place during the morning, although
models are hinting at a dry slot partially clearing the sky near
peak heating. SPC has far south central ND and the southern James
Valley in the marginal outlook, and would not be surprised to see
another northward adjustment when the new Day 1 is updated late
tonight.
WPC also has much of western and central ND in the marginal risk
for excessive rainfall for late tonight through Thursday/Thursday
night. Precipitable water increases from 0.77" from the 12Z KBIS
sounding this morning, to 1.1" - 1.4" during the day Thursday.
This value is near our daily max for mid September so plenty of
moisture in place. Synoptic and convective forcing mechanisms
aplenty so should be able to squeeze much of this moisture out of
the atmosphere. Will mention the threat for moderate to heavy
rainfall in the HWO and social media.
Precipitation ends from west to east on Friday as the mid level
low moves east into the upper midwest.
.LONG TERM...(Friday night through Wednesday)
Issued at 324 PM CDT Wed Sep 14 2016
Another short wave ridge moves across the region on Saturday,
followed by a short wave trough moving east across southern
Canada Sunday. Will maintain dry conditions both days. Highs in
the 70s Saturday then mid 70s to mid 80s for Sunday thanks to
southerly flow ahead of the aforementioned Canadian trough. Flow
becomes more active early to mid next week transitioning to
southwesterly as a potent long wave trough develops over the
western CONUS.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 623 PM CDT Wed Sep 14 2016
Widespread mvfr associated with showers and scattered
thunderstorms will spread over west and central North Dakota
around sunrise Thursday. IFR conditions are possible due to
ceilings KDIK-KBIS-KJMS after 10z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...NH
LONG TERM...NH
AVIATION...WAA
Area Forecast Discussion
National Weather Service Denver/Boulder CO
850 PM MDT WED SEP 14 2016
.UPDATE...
Issued at 830 PM MDT Wed Sep 14 2016
The thunderstorm that was warned earlier this evening continues to
move to the east northeast across northeast Weld County with a
lot of lightning. We still have showers and weak thunderstorms
moving across the mountains this evening...and these will likely
spill out to the plains...but we should not see any storms as
strong as what we saw earlier. By midnight...there may still be a
few showers or storms in far northeast Colorado or near the
Wyoming border...but expect the rest of the activity to have died
down.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 335 PM MDT Wed Sep 14 2016
Scattered showers have been moving across the mountains this
afternoon, but nothing has developed on the plains yet. Moderate
to strong southwest flow aloft continues ahead of the trough axis
which is moving into the northwest corner of the state at this
time. The latest HRRR model runs continue showing a round of
showers moving over the plains during the evening, so will stick
with that. Gusty winds, brief rain and small hail will be the main
threat. The airmass on the plains looks like it will remain capped
until the upper trough moves out of the mountains.
On Thursday, westerly flow aloft will continue in the wake of
tonight`s upper trough. Temperatures will be a few degrees cooler
than this afternoon, but the airmass will become unsettled in the
afternoon, leading to isolated showers developing again. Mountain
areas may see a little bit more shower activity than on the
plains.
.LONG TERM...(Thursday night through Wednesday)
Issued at 335 PM MDT Wed Sep 14 2016
The upper trof will begin to move out into the northern high
plains Thursday night and Friday. This trof send a weak frontal
surge through Northeast Colorado with shallow upslope flow and a
bit cooler temperatures for Friday. Overall the airmass will be
drier on Friday but with heating and some lingering moisture there
will still be isolated afternoon/evening showers mainly over
mountains and higher terrain areas.
For Saturday, some warming but weak trofiness upstream will still
help support showers and thunderstorms mainly mountains and Palmer
Divide.
For Sunday through Tuesday there will be a drier West to Southwest
flow over Colorado. This will result in warmer temperatures with
readings back into the 80s across the plains through early next
week. By next Wednesday the next upper trof will sweep across the
region with the bulk of the moisture remaining North of Colorado.
Certainly some cooler temperatures and a slight chance of showers
for now. The european solution is much slower and low confidence
at this time on any one solution.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday afternoon)
Issued at 848 PM MDT Wed Sep 14 2016
Winds have been a challenge tonight with thunderstorms and
boundaries. We are not totally done with the chaos as more showers
spill off the mountains in the next 2 or 3 hours. Another outflow
boundary could send westerly winds spreading across the metro
area...but for the most part we will see downslope flow this
evening and overnight.
The surface pattern will have a developing lee trough in eastern
Colorado...so winds tomorrow will be be northwesterly because of
the lee trough. There may be a few storms tomorrow but they should
be mostly over the Palmer Divide and foothills during the day.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...RTG
SHORT TERM...Dankers
LONG TERM...Entrekin
AVIATION...RTG
Area Forecast Discussion
National Weather Service Burlington VT
1016 PM EDT Wed Sep 14 2016
.SYNOPSIS...
A cold front has exited the region and high pressure will build in
tonight through Friday. We will see high temperatures a few degrees
below normal on Thursday despite plenty of sunshine. Temperatures
will climb a few degrees above normal on Friday with a continuation
of full sun. Our next chance of precipitation will come later on
Saturday and especially Saturday night into Sunday as a trough of
low pressure moves into the region.
&&
.NEAR TERM /UNTIL 11 AM THURSDAY MORNING/...
As of 1016 PM EDT Wednesday...No major changes made with this
update, though I did increase sky cover a bit through midnight in
the Adirondacks and the northern Green Mountains of the Vermont.
Satellite trends indicate a slow erosion of this stratocu field,
and some indication in FSO and MPV metars of some breaks in
overcast. Temperatures locally warmer underneath these clouds
despite the background lower-tropospheric cold/dry advection
regime in place. Given the satellite trends and as indicated in
RAP BUFKIT RH cross sections still feel that these clouds should
continue to erode with stronger cooling taking place across these
areas once they go clear. Rather strong northerly wind fields per
regional Doppler VWPs still support a later timing on river valley
fog potential, and so I`ve made no changes there. Lows also appear
on track in the upper 30s to upper 40s/around 50, with the
stronger cooling taking place overnight as skies fully clear.
Previous near-term discussion issued at 311 PM follows...
Trend will be for quieter weather with cold front exiting and
high pressure building in.
Tonight: Cold front is just about ready to exit south central
Vermont late this afternoon with a narrow band of showers and
isolated thunderstorms along it where narrow axis of instability
developed with highs climbing into the 70s. Sufficient deep layer
shear has existed over the area all day and it was just waiting
for some instability to enhance the convective potential. This
activity should exit the southern halves of Rutland and Windsor
counties by 5pm with just some lingering light showers possible
over Vermont through about 7pm. Gusty northwest winds across the
area will taper off toward midnight and some clearing is expected
to develop. This will allow fog to form in the favored locations
across the northern Adirondacks and the eastern half of Vermont.
Lows will generally be in the 40s to around 50 with some upper 30s
in the mountains.
Thursday: Fog burns off by mid-morning and a good deal of
sunshine should prevail for much of the day as high pressure
promotes subsidence. Weaker pressure gradient will also exist and
this will allow winds to generally be under 10 miles per hour for
a better part of the day. High temperatures will be a few degrees
cooler than normal with highs in the 60s to around 70.
&&
.SHORT TERM /11 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
As of 308 PM EDT Wednesday...Quiet weather continues into the
short term with expansive high pressure at the surface and aloft
dominating regional conditions. Mainly clear/sunny skies will be
the rule with patchy early morning fog a good bet in favored
locales Thursday night. Leaned toward bias- corrected MOS-based
output in regard to temperatures, especially at night when this
cluster of solutions tends to handle radiational effects better
than other guidance. This would support lows generally in the 35
to 45 range Thursday night with some variability, then somewhat
milder by Friday night (40s to lower 50s) as southerly return flow
on the back side of the departing high develop. Highs on Friday
mainly in the lower to mid 70s under wall to wall sunshine. Given
the cooler readings on Thursday night, some patchy light frost may
also be possible in the sheltered valleys of the northern
Adirondacks and far northeastern VT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 308 PM EDT Wednesday...Looking further out, a persistence
forecast will be offered for next weekend into early next week.
The primary weather features over the next 7 days will feature a
weak cold front and associated threat of showers/isolated thunder
later Saturday into Sunday, then a trend toward drier/warmer
conditions by much of next week as deep-layer ridging builds
across the area.
This morning`s medium range output still on track showing a
dampening mid-level shortwave trough and attendant surface front
tracking into the area by later Saturday into Saturday night. While
the baroclinic gradient along the surface boundary isn`t all that
impressive, modest height falls along with good low level moisture
transport (pwats to 1.75 inches) should ensure rather widespread
coverage of showers and have continued the idea of 60-80 percent
pops during this period. While surface-based instability is minimal,
quite an impressive low to mid level southerly jet in advance of the
boundary will transport slightly steeper mid-level lapse rates
northward into our area - fostering at least a low-end threat of a
few thunderstorms as well. Temperatures during this period will
average near or slightly above seasonal norms with highs Sat/Sun
mainly in the lower and mid 70s and overnight lows Saturday night in
the upper 50s to lower 60s.
After some lingering clouds and post-frontal scattered light
showers/sprinkles across the north Sunday night/Monday morning a
general trend toward dry and seasonably warm weather is expected for
much of next week. Minor differences in the northern stream still
exist among this morning`s GFS/Euro output, with the latter still
suggesting slightly flatter flow and possible weak additional
shortwave energy swinging quickly through by the middle of next
week. Given lack of consensus will maintain dry weather from Monday
afternoon onward along with slowly warming temperatures and clear to
partly cloudy skies. Indeed, a quick look at mean afternoon 925 mb
temperatures from Tuesday into late week suggests we (KBTV) may not
be done with the 80F readings quite yet.
&&
.AVIATION /02Z Thursday THROUGH Monday/...
Through 00Z Friday...A ridge of high pressure will build east from
the Great Lakes through the period. Mainly VFR conditions expected
through the period. The region will be under cold air advection
overnight. Winds above the surface appear to be strong enough
overnight to prevent the formation of fog in the sheltered valleys
of Vermont and northern New York overnight. Thus, have not
included any mention of fog in the TAFS overnight. Also, some
lingering cloud cover over the Adirondacks and northern Vermont
will also inhibit fog development overnight as well.
Outlook 00Z Friday through Monday...Expect VFR conditions from
00z Friday through 18z Saturday with high pressure over the area.
A trough of low pressure will move in Saturday afternoon through
Sunday and this will increase clouds and showers over the area
resulting in MVFR/IFR ceilings and visibilities. Conditions will
trend toward VFR by Monday.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Evenson
NEAR TERM...Evenson/Loconto
SHORT TERM...JMG
LONG TERM...JMG
AVIATION...Evenson/WGH
Area Forecast Discussion
National Weather Service Columbia SC
1018 PM EDT WED SEP 14 2016
.SYNOPSIS...
Moisture will remain over the region through much of the week in
the easterly flow between high pressure to the north and Tropical
Storm Julia just south of the area. This will result in unsettled
weather, especially across the southern Midlands and CSRA.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
TS Julia remains a minimal tropical storm located just offshore
Fripp Island at 5 pm based on radar imagery. Showers have become
widely scattered across the Midlands and CSRA this evening. Tight
moisture gradient across the west Midlands/Piedmont. Based on
latest HRRR guidance and radar trends...cut pops back overnight
from previous forecast.
Julia is forecast to gradually lift northeastward along the coast
while widespread stratus is expected to redevelop over the area.
The cloud cover and possible showers will limit radiational
cooling and overnight lows will be in the upper 60s to lower 70s.
If winds fall off enough over the northern and western Midlands
there could be some patchy fog that develops.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Tropical Storm Julia will continue to be the main focus
through the end of the week and into the weekend as it lingers
near the SC coast. Surface high pressure over the Great Lakes this
afternoon will continue to build east and south through the end of
the week. This will continue the moist onshore flow along the
coast and hold Julia or her remnants near the coast. All of the
short term models move Julia very slowly northward tonight into
Thursday...then seem unsure were Julia will move. The center
appears to wobble in the vicinity of srn SC/sern GA through the
weekend. Very tight precipitable water gradient across the area
this afternoon and expect this to continue through Thursday. Values
over 2.0 inches over much of the central and eastern Midlands into
the CSRA. This is approximately 125 to 150 percent of normal for
this time of year. So any showers/thunderstorms that develop over
the region will have the potential to produce locally heavy
rainfall. Kept the highest pops across the southeast Midlands into
the CSRA. Cloudiness should limit instability and with such a
moist atmosphere severe thunderstorm chances should remain low.
Followed the guidance consensus for high temperatures in the low
to mid 80s and lows in the upper 60s to lower 70s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The GFS and ECMWF indicate high moisture through much of the
medium-range period associated with a long-fetch easterly flow
south of pressure ridge...and remnants of Julia that become more
diffuse...off the east coast. A cold front approaching from the
northwest may move into the forecast area Monday. Expect mainly
scattered showers and thunderstorms especially near the times of
maximum heating with coverage limited by upper ridging. The GFS,
ECMWF, and EKD MOS support pops 30 to 50 percent. The MOS
indicates near normal temperatures through the medium-range
period.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Earlier scattered showers have diminished over our FA. TS Julia
centered near the SC coast. Most associated moisture and
precipitation south of our terminals, with drier air to the north
and west of the cyclone. Main near term concern involves expected
stratus development tonight due to E to NE low level flow and
moist low levels. Guidance in good agreement with stratus
formation. Current observations indicate stratus has developed
near the coast, and is drifting inland. For now, indicated IFR
CIGS. In addition, some fog could develop, mainly northern areas,
where winds are lighter and skies clearer. Also included mention
of MVFR fog at CAE/CUB, and at fog prone AGS. Expect a slow lift
to VFR by late morning to midday Thursday. Julia expected to move
very slowly near of just offshore the SC coast. Expecting mainly
diurnal scattered showers, and possible an isolated thunderstorm,
for our FA Thursday. For now, think VCSH will suffice.
EXTENDED AVIATION OUTLOOK...Chance of mainly afternoon/evening
thunderstorms, as well as late night/early morning fog/stratus.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Dodge City KS
1055 PM CDT WED SEP 14 2016
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
Issued at 1053 PM CDT Wed Sep 14 2016
WV imagery indicates a southwest flow aloft prevailing across the
Western High Plains as an upper level trough of low pressure moves
eastward across the Northern Rockies. Near the surface, a lee side
trough of low pressure is slowly developing across eastern Colorado.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 1244 PM CDT Wed Sep 14 2016
Water vapor loop and RAP analysis showed a mature mid-latitude
cyclone spinning over southeastern Idaho into adjacent western
Wyoming. There was also a subtropical jet streak nosing into western
Kansas, with a plume of mid level moisture extending from
southeastern Arizona through central New Mexico into the Central
Plains. There were a few sprinkles and very light rain showers over
southeastern Wyoming into the western Oklahoma Panhandle, but as of
midday, these were starting to dissolve. Low clouds were still
holding tough across far western into northern Kansas, which were
keeping temperatures down into the upper 50s to around 60. The low
level flow was very weak with a remnant surface high in place. This
will weaken and shift quickly east, being replaced by a leeside
trough across eastern Colorado. Strong and isolated severe
thunderstorms along and a little east of the I-25 Urban Corridor of
Colorado will shift east this evening, but will encounter an
increasingly stable atmosphere and should die off by the time they
reach the Colorado border. We will hold on to some 20-30 POPs across
the far western sections of the forecast area, mainly Elkhart to
Johnson to Syracuse. We will also continue POPs, but lower them a
bit over the remainder of west central and southwest KS, as it
appears the warm air advection will be strongest farther north into
Nebraska and northern Kansas.
For Thursday, a warm up is in store with a return to southerly winds
along with increased moisture. A trough axis will set up from east
central Colorado into central Nebraska, and this should be a focus
for late afternoon and evening thunderstorm development. Again, the
best focus should be farther north where stronger mid and upper
level winds will be. This is also where the SPC Day 2 Slight Risk
resides, which barely clips parts of west central KS (including
Wakeeney and Hays). Any thunderstorm activity south of this area
deeper into southwest KS should be isolated to widely scattered in
nature as far as coverage goes, given the weaker forcing for ascent.
.LONG TERM...(Thursday night through Wednesday)
Issued at 317 PM CDT Wed Sep 14 2016
On Friday, the best area for convective activity will be across far
south central KS as the frontal boundary tied to the Northern Plains
upper low continues to push south. A subtropical jet core will
extend from southern New Mexico into southern and eastern Kansas,
and would provide enough deep layer shear to support some organized
severe thunderstorm structures. That said, the low level kinematics
will be rather poor, so inflows into convective storms could be a
detriment to organized severe storms. The southern branch jet will
not change much on Saturday, but a weak surface high will have
greater influence, so precipitation chances Saturday look fairly
low, except perhaps along the Oklahoma border where better residual
moisture will reside. Weak upslope flow in southeastern Colorado may
initiate a few storms as well, which could roll into far southwest
KS by late afternoon/early evening.
Beyond Saturday, the synoptic pattern will shift back to northern
branch dominance, as a very strong Pacific jet noses into the
Pacific Northwest region and Northern Rockies. The synoptic pattern
will favor a warm up back into the 80s early next week, but overall
precipitation chances will be lower as there will be an absence of
forcing for ascent with only weak flow in the mid levels across the
Rockies. There is a big discrepancy between the deterministic ECMWF
and GFS going into mid next week, as the GFS shows a big trough
moving into the Central Rockies, whereas the ECMWF keeps the lowest
heights way out along the West Coast (and hence dry over our part of
the world).
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 659 PM CDT Wed Sep 14 2016
A surface trough will remain in the lee of the Rockies through the
period, resulting in southeast to south winds that will be
stronger during daytime heating. Low MVFR or IFR stratus may
develop after 09z as low level moisture influx from the south
combines with diurnal cooling. This should improve to MVFR/VFR by
16-17z with daytime heating. Thunderstorms may affect KHYS after
06z and then afternoon thunderstorms may affect any of the TAF
sites after 20z as an upper level trough traverses the central
plains.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 54 78 62 85 / 20 10 30 40
GCK 53 77 60 85 / 10 10 20 40
EHA 55 75 59 86 / 20 30 20 30
LBL 55 77 62 86 / 10 20 20 40
HYS 52 71 62 83 / 20 10 30 50
P28 57 79 65 85 / 30 10 30 40
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...JJohnson
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Finch
Area Forecast Discussion
National Weather Service Goodland KS
640 PM MDT WED SEP 14 2016
.UPDATE...
Issued at 640 PM MDT Wed Sep 14 2016
Minor adjustments were made to PoPs to account for current trends
on radar/satellite. Based on WV shortwave is still in place,
though it appears main region of forcing on RAP analysis will pass
north of our CWA. Short range/high resolution guidance continues
to favor the northern part of our CWA (in line with previous
forecast) and this continued to be favored. Main change was to
trend PoPs down and adjust timing.
During an earlier update fog was added based on strong signal in
most guidance. Consensus of high resolution and short range
guidance favors the west where clearing may take place and the
northeast where winds will be lighter. I have less confidence in
fog coverage for most locations due to mixing from BL winds
15-28kt.
&&
.SHORT TERM...(tonight and Thursday)
Issued at 127 PM MDT Wed Sep 14 2016
Latest upper air analysis shows a closed low over the Pacific
Northwest. Rotating around the closed low are numerous short wave
troughs. The short wave trough that will bring rainfall to High
Plains is already triggering scattered thunderstorms ahead of it in
Colorado. At the surface a trough was located over Eastern
Colorado, running parallel to I-25. As the short wave trough
approaches the surface boundary and the nose of the low level jet
develops overhead, thunderstorms should develop along it. However
just east of this surface boundary the environment is very stable,
as evidence by the wave clouds seen on satellite. Therefore do not
expect the storms to move very far into the Tri-State Area,
remaining mainly west of Highway 59.
The primary threats with any severe storms that develop will be
quarter size hail and wind gusts of 60 MPH, although am not very
optimistic with severe storms developing in the East Central CO
counties.
This evening the best rainfall chances will be north of Highway 36
as the short wave trough moves northeast into Nebraska, remaining
north of the Tri-State Area. There is some spotty lift which
extends over the area from the trough to the north, however the
environment will be too dry to support much beyond isolated storm
development. Toward morning another short wave trough develops just
east of the Tri-State Area. The best chances for storms with this
trough will be east of Highway 283.
Thursday any lingering rainfall will end from west to east as drier
air and subsidence move in behind the departing short wave trough.
With a warmer air mass moving in as well as clouds clearing,
temperatures will be much warmer that today. During the afternoon a
pre-frontal trough will move into the Tri-State Area from the north.
This may serve as a focus for storm development as an upper level
short wave trough develops overhead. However the best instability
will be east of the Tri-State Area. So while a few severe
thunderstorms cannot be ruled out during the afternoon, believe the
majority of the storm activity will be east of the Tri-State Area.
.LONG TERM...(Thursday night through Wednesday)
Issued at 127 PM MDT Wed Sep 14 2016
Cold front will slowly traverse the area Thursday night from west
to east with a chance for showers and thunderstorms. As the upper
low in the northern plains moves towards the Great Lakes on
Friday, precipitation chances will end early in the day. Will get
into more of a northwest flow on the backside of the system, with an
embedded weak shortwave trough bringing low chances of showers and
thunderstorms beginning late Friday night through Saturday. Deep
layer shear and instability profiles appear favorable Saturday
afternoon for a severe threat (shear around 50kts and instabilty
up to 2500 j/kg), although with the relatively weak forcing coverage
may not be that great.
Dry conditions are forecast for Sunday through Tuesday as a ridge
centered over the southern plains results in rising heights. The
ridge begins to break down late in the period with the next system
approaching the northern Rockies, with shower and thunderstorm
chances returning.
Temperatures will be slightly below normal Friday and Saturday,
then warm to slightly above normal for the remainder of the period
under the influence of the southern plains ridge.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 525 PM MDT Wed Sep 14 2016
Showers or possibly a thunderstorm may impact the KMCK terminal
late this evening and early Thursday morning. Confidence in
coverage of thunderstorms is limited, so I only included VCSH
group for now. Stratus is in the process of clearing at both
terminals, and a period of VFR conditions should prevail during
the evening. Stratus and fog should then redevelop and spread back
over KMCK after 05Z, with LIFR conditions returning by 11-12Z.
I have less confidence in sub VFR conditions at KGLD due to
winds in the 12-15kt range and low level wind shear, which could
help keep the lower levels drier. There could still be a period of
light fog or stratus around sunrise, but confidence in prevailing
conditions is low at KGLD and the stronger stratus/fog signal in
guidance is at KMCK. Both terminals should be VFR by late Thursday
morning as surface low pressure shifts east, moving main low level
axis out of the area of both terminals.
&&
.GLD Watches/Warnings/Advisories...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...JTL
LONG TERM...024
AVIATION...DR
Area Forecast Discussion
National Weather Service Lincoln IL
911 PM CDT WED SEP 14 2016
.UPDATE...
Issued at 910 PM CDT Wed Sep 14 2016
High surface pressure centered over the Great Lakes will help to
keep precip at bay in central Illinois the rest of the night. A
weak shortwave moving toward central Illinois from southern
Missouri will bring increasing rain chances west of I-55 Thursday
morning. We have kept the rest of the night dry in our forecast
area, with varying levels of mid and high cloud cover streaming
into Illinois from the southwest. There is some indication that
surface winds may trend southeast late tonight bringing increasing
low clouds and milder dewpoints. That would increase chances of
light fog later tonight, but widespread dense fog is not
anticipated. Lows tonight are expected to settle out in the upper
50s N of I-74, with low 60s in the remainder of our forecast area.
Rain chances should hold off until around sunrise with slight
chance PoPs west of Jacksonville to Rushville to start the day.
Rain chances will expand eastward during the day, but better
chances will remain west of Jacksonville to Galesburg.
Updates tonight were main to remove any lingering rain chances
from areas southeast of I-70, and to add patchy fog late tonight.
The remainder of the forecast looks on track. Updated info is
already available.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 254 PM CDT Wed Sep 14 2016
Satellite imagery depicts weak wave now from central IL into central
MO. This feature is aiding in triggering minor convection in the
best unstable air over southern IL. Best dew points and CU field
show unstable airmass over southeast CWA, with SBCAPES to near 2300.
As the wave moves through, should continue to have slight chance of
pcpn in the early evening.
As for overnight, subsidence behind the wave will aid in minor
clearing of high clouds. With ample moisture, this should be enough
for redevelopment of stratus and some fog over area by morning.
Models now bit quicker in moving overrunning back over front zone
and so will increase pops for tomorrow with this trend.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 254 PM CDT Wed Sep 14 2016
Low pressure moving from the northern Plains into the northern Great
Lakes Thursday night through Saturday night...and the attendant warm
front lifting northward through the area Thursday night and cold
front pushing eastward through the area Saturday will be the main
features for central IL weather to start the weekend. Expect periods
of showers and thunderstorms Thursday night through Friday as
central IL remains in the warm sector...then a more focused period
of thunderstorms ahead of the cold front Friday night into Saturday.
The cold front looks to reach Galesburg early Saturday morning and
Lawrenceville Sunday morning with showers ending behind the front.
High pressure building into the Midwest behind the front will bring
dry and mostly sunny conditions Sunday through at least Tuesday.
Timing of the next storm system continues to be highly uncertain.
The 12Z GFS model features a faster timing with a deep upper low
moving into the central U.S and developing precipitation by
Wednesday night for west central IL, while the 12Z ECMWF keeps the
upper low much farther west at that time, holding precipitation off
for a few more days. For now, have kept mentionable precipitation
out of most of the area through Wednesday.
Temperatures through the extended forecast are not expected to
fluctuate much with highs mainly upper 70s and lower 80s. Lows
should range from upper 50s to mid 60s. Overall, the coolest night
looks to be Sunday night in clear skies and light winds associated
with high pressure.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 657 PM CDT Wed Sep 14 2016
The moisture convergence axis has been lingering across our far
southeast counties, well south of the terminal sites. Isolated
showers and storms have trended down over the last hour, and that
should continue with loss of daytime heating. The low level flow
out of the northeast should help to keep the bulk of the boundary
layer moisture south of the TAF sites, but we can not rule out
some MVFR ceilings and/or MVFR vis in fog late tonight. Better
chances for MVFR conditions should be near the southern terminals
of SPI and DEC. The potential for light fog down to 5sm could
extend farther north per HRRR output, so have included light fog
in all terminals late tonight.
Cloud cover will be variable on Thursday as dry air mixing from
about the cloud layer, but cloud heights should rise to VFR
by 14-15z and remain VFR through the day.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...Goetsch
LONG TERM...Onton
AVIATION...Shimon
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
946 PM CDT WED SEP 14 2016
.UPDATE...
Issued at 940 PM CDT Wed Sep 14 2016
Short term forecast looks like it`s on track for the rest of the
night. Afternoon/early evening convection has dissipated. Weak
warm advection toward daybreak could produce some spotty showers
or thunderstorms...primarily west of the Mississippi River.
However, QPF is very light on the operational models and the ESRL
and operational HRRR models show only very isolated showers toward
12Z. Could see some patchy fog developing before sunrise, but with
pretty extensive cloud cover I don`t think it will get dense.
Carney
&&
.SHORT TERM... (Through Late Thursday Night)
Issued at 344 PM CDT Wed Sep 14 2016
(Tonight)
Have lingering PoPs this evening for portions of southeast Missouri
and southwest Illinois in closer proximity to sfc frontal boundary.
These showers/storms should fade with loss of instability. Could see
some isolated showers/storms again very late tonight as broad
warm/moist advection occurs at low levels. Lows tonight should be on
the mild side due to cloud cover and high dewpoints.
(Thursday - Thursday Night)
Subtle shortwave trough looks to eject out of the southern Plains
during the day on Thursday. This should help foster the development
of scattered showers and thunderstorms with the best chance being
across portions of central Missouri during the afternoon hours.
Highs tomorrow will be fairly similar to today or ranging from the
upper 70s across northern sections of the area to mid 80s.
Chances of thunderstorms continue to increase as we head into
Thursday night as low-level jet intensifies. Still however quite a
bit of model disagreement wrt timing and track of individual
vorticity maxima within the broad SW flow aloft both on Thursday and
Thursday night...so leaned more toward high chance or scattered
wording instead of likelies. Lows on Thursday night should once
again be mild for mid September and be on par with what is expected
of tonight.
Gosselin
.LONG TERM... (Friday through Next Wednesday)
Issued at 344 PM CDT Wed Sep 14 2016
(Friday-Saturday night)
The period begins with a short wave pushing through the southern
part of the CWA during the day on Friday. A cold front should push
into the area area on friday, but there are timing differences
noted between the GFS/NAM and ECMWF. The ECMWF has been consistent
in model to model runs lately, thus I put more weight toward it
for solution to frontal passage. The cold front will likely be
somewhere just south of the St. Louis area Friday night.
There will be some showers and thunderstorms ahead of the front on
friday. Additionally,there could also be some post frontal
showers and thunderstorms that linger well into Friday night over
parts of central missouri into IL The area will see highs in the
lower 80s on friday and saturday with lows in the lower 60s.
The cold front should clear the CWA at around just before 18z on
Saturday. I can not rule out some showers and thunderstorms during
the day on Saturday with close orientation of the boundary in the
extreme southern part of the CWA.
Kelly
(Sunday - Next Wednesday)
A relatively dry stretch of weather looks to be in store from Sunday
through next Tuesday with cold front that passed through earlier in
the weekend staying to the south of the CWA. Mid/upper level ridging
attempts to build in heading into next week which should lead to a
moderation in temperatures. Seasonably warm conditions appear likely
next Tuesday and Wednesday both day and night. GFS/ECMWF diverge a
bit for midweek next week as the GFS begins to break down the ridge
sooner with another frontal boundary approaching the CWA along with
a chance of storms. European model however keep the mild and dry
weather going at least through Wednesday with the ridge still in
control.
Gosselin
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 631 PM CDT Wed Sep 14 2016
Scattered thunderstorms over the eastern Ozarks into southwest
Illinois should dissipate over the next 2 to 3 hours with loss of
daytime heating. Weak low level southeast flow should allow for
increasing moisture and guidance is pretty insistent that low end
MVFR and possibly IFR ceilings will develop over the region after
06Z. These low ceilings and possibly widely scattered showers and
thunderstorms will likely persist into mid-morning Wednesday.
More widely scattered thunderstorms are possible Wednesday
afternoon.
SPECIFICS FOR KSTL:
Isolated thunderstorms southeast of Lambert should stay away from
the terminal this evening. Expecting MVFR and possibly IFR
ceilings to develop late tonight due to increasing low level
moisture on weak south-southeast flow. MVFR ceilings will likely
persist through 14-18Z before rising to VFR in the afternoon.
Widely scattered afternoon and evening thunderstorms are again
possible...but have not mentioned in TAF at this time as
confidence is low.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
353 AM CDT Thu Sep 15 2016
.SHORT TERM.../Today/
Issued at 349 AM CDT Thu Sep 15 2016
High pressure to push off to the East today and although the high
has been pushing in dry air...we will saturate and see precip today.
The models however...even the hi-res models...are having a tough
time resolving just where initially and how quickly this will
happen. However...it`s clear that NW Iowa and locations to the North
and West are already seeing saturation as a stratus deck has been
evident there since the beginning of the shift and now FSD is
reporting light rain and some fog.
The hi-res models that have picked up on this the best are the ARW
and NMM and as such I`ve modeled sky condition and pop trends along
those models solutions. I`ve increased pops this morning across the
Northwest and decreased them across the South central as a result.
By late morning into the early afternoon theta-e advection and
forcing move into the Western third of so of the state so I have
increased pops accordingly in these areas. The better forcing
outruns the better instability and shear so while we will see some
decent qpf amounts in the afternoon...the better chance for
strong/severe storms should remain to the West of the forecast
area...perhaps eclipsing the far Western portion of the forecast
area by later this afternoon. Some areas may see heavy rainfall
later in the afternoon but at this point I`m not thinking flash
flooding since it`s been some time since the last rainfall and PWATs
are under 1.75 inches. This may not be the case in later periods
since precip is expected to be continuing through Friday but I am
not considering any headlines for today. I did nudge highs down a
degree or so today from the expected thicker cloud cover.
.LONG TERM.../Tonight through Wednesday/
Issued at 349 AM CDT Thu Sep 15 2016
The primary concerns through the period will remain precip chances
into Friday, and then another potential window into the middle of
next week. At onset, remnants of current NE convection are expected
to persist into the immediate MO River Valley driven by weak to
moderate large scale forcing with contributions of diffluence aloft,
DPVA and theta-e advection. This will likely persist into the night
across IA in some form but remain fairly unfocused as IA is
essentially in the warm sector with little baroclinicity. Soundings
suggest it will be only slightly elevated, likely around 500m per
soundings, and driven by 20-30kts of inflow as shown along the 300K
isent surface. It is expected to remain sub-severe however as
instability should be relatively weak with minimal effective shear.
Additional more potent surface based convection may develop across
NE during peak heating but end up with a similar fate per the
reasoning above. Additional convection may develop into Friday
along and ahead of a rather unorganized frontal boundary, but
synoptic scale forcing contributions look weaker this far south
and mainly kinematic/mid based.
Rainfall may be more of a concern than severe. Precipitable water
and warm cloud depth values are not extreme versus climatology, but
there will be a more anomalous supply of 0-1km moisture which could
certainly boost rainfall amounts. The mean wind changes little Thu
Night into Fri and remains weak with only around 20kts of flow so
training is certainly possible. This could result in isolated 1-3
amounts possible before the precip diminishes NW-SE late Fri. The
00z GFS has lingered precip later into Fri Night and even early
Sat morning south with stronger forcing moving out of the Plains
but this is an outlier versus other solutions and is new from
previous runs so has been left out for now but is something to
watch.
After muggy weather tonight and Friday, fair weather and more
seasonal temperature and humidity levels are the offing for the
weekend as high pressure settles into Iowa behind the departing
Great Lakes upper low. The question will turn to when to introduce
precip again. The GFS and ECMWF have come into somewhat better
agreement since yesterday with a weak MO Valley short wave Sunday
followed by central Plains ridging into Tuesday. Forcing with the
wave is weak or neutral keeping the forecast dry. A weak wave will
top the ridge late Monday however with a front just dropping into
Iowa resulting in some brief low end PoPs by then, but appreciable
chances do not return to the forecast until around Wednesday when
heights lower ahead of the NW CONUS trough resulting in a fairly
strong surge of theta-e advection into the MO Valley. This will
also bring another bout of late summer humidities and slightly
above normal temperatures.
&&
.AVIATION.../For the 06Z TAFS through 06Z Thursday night/
Issued at 1150 PM CDT Wed Sep 14 2016
Large surface high pressure continues to provide dry air over the
forecast area and looks to ward off the MVFR stratus until mid to
late morning Thursday to mainly FOD and DSM. The latest HRRR has a
good handle on the ceiling trends and keeps ALO, OTM, and MCW in
VFR until the afternoon. Introduced MVFR visibility and ceilings
toward the end of the forecast period with the scattered showers
and thunderstorms expected over much of central Iowa.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...FAB
LONG TERM...Small
AVIATION...Podrazik
Area Forecast Discussion
National Weather Service Lincoln IL
300 AM CDT THU SEP 15 2016
.SHORT TERM...(Today and tonight)
ISSUED AT 300 AM CDT Thu Sep 15 2016
The weak cool front that pushed through southeast Illinois yesterday
afternoon has pushed well south of the Ohio River early this
morning. High pressure over the upper Great Lakes is governing our
weather this morning with slightly drier air filtering in from the
north. Meanwhile, a deep trof at 500 mb was edging slowly across
the northern Rockies this morning and this feature will be
bringing an increasing chance for showers and thunderstorms back
into our area, especially tonight and Friday. Will still be
carrying some slight chance POPs over extreme west central
Illinois today but those have been shifted further west than
previous forecasts as the surface high will continue to dominate
most of our area through this afternoon.
With the main forcing remaining out to our west from the 500 mb trof
into early this evening, have delayed the onset of the higher POPs,
especially across the east where it may take all night to see the
showers push into that area. Further west, closer to the better 850
mb theta-e advection, we should see high chance POPs push into west
central Illinois after midnight with dry conditions continuing in
areas east of the Interstate 57 corridor. With the drier look to
the soundings, especially in the low levels later this morning,
have edged afternoon highs at or just above guidance with most
areas seeing highs range from around 80 north to the middle 80s over
southeast Illinois.
&&
.LONG TERM...(Friday through Wednesday)
ISSUED AT 300 AM CDT Thu Sep 15 2016
Upper low currently over eastern Idaho should open up as it crosses
the Dakotas on Friday. Tropical moisture plume will continue to
surge in from the southwest ahead of the attendant cold front, with
precipitable water values in the 1.8 inch vicinity continuing
through much of Friday. Cluster of showers and thunderstorms which
should be ongoing across the western CWA by early morning will not
be in a great hurry to cross the area on Friday, so some locally
heavier rains will occur at times during the day. With the actual
front not expected to cross the area until Saturday, high rain
chances will continue over the southeast third of the forecast area
until early evening Saturday. Some variations among the models on
the back edge of the rain shield, with the GFS and Canadian models
keeping a wet scenario until the front actually passes, while the
ECMWF model has more of a sharper back edge and the NAM brings a few
more afternoon showers ahead of the front. Will continue to side
with the more consistent ECMWF solution and only mention slight
chances along and northwest of the Illinois River on Saturday.
Latest GFS and ECMWF are in reasonable agreement now for the first
half of the new week, with the main storm track close to the
Canadian border and an upper ridge starting to amplify from the
southern Plains into the mid-Mississippi Valley. Ridge-riding upper
waves are progged to mainly track around the forecast area, although
the GFS is much further south with the shower/storm threat Monday
night and early Tuesday. Right now, will limit any slight chance
PoP`s to the northwest half of the area Monday night, closer to the
fringe of the ECMWF solution.
Not a lot of change in temperatures through the period, with
temperatures near or just above normal. Some drier air will move
through Sunday and Sunday night, before dew points build once again.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1152 PM CDT Wed Sep 14 2016
High pressure centered to the northeast of our area will create a
northeast flow into central Illinois, bringing somewhat drier and
cooler air. Mid and high level clouds streaming into Illinois from
the southwest are the result of a weak shortwave drifting toward
Illinois over the top of the ridge established in the southeastern
states. Despite thin spots and breaks in the clouds, the overall
effect should be to reduce the potential of any dense fog later
tonight. HRRR has backed off on much in the way of fog at the TAF
sites, but will still include a few hours of MVFR 5SM BR
surrounding sunrise.
Southeast return flow will become established west of Illinois
tomorrow, keeping better rain/storm chances through the morning
and early afternoon west of our forecast area. The consensus of
the high res models show some showers reaching near Springfield
after 21z, so have included a VCSH for late afternoon at SPI.
Instability appears weak, so left thunder out for now.
Winds will start out light northeast across the board. As high
pressure pulls farther away to the east, winds will veer to the
southeast by late afternoon or early evening, when rain chances
start to increase from west to east. PIA could see a few showers
after 03z near the end of this TAF period.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Omaha/Valley NE
354 AM CDT THU SEP 15 2016
.SHORT TERM...(today through Saturday)
Issued at 214 AM CDT THU SEP 15 2016
Latest water vapor imagery and RAP 500mb analysis shows mid-level
low opening as it lifts northeast over the Northern Rockies and
toward the Northern Plains. Ahead of this, strong low-level moist
advection continues early this morning with surface dewpoints
currently in the lower to mid 60s with upper 60s forecast by this
afternoon. This is ahead of a fairly weak Pacific front which per
latest surface analysis, extends south from low pressure over
southwest North Dakota into far western Nebraska and eastern
Colorado. Early morning regional radar mosaic shows a thunderstorm
complex quickly pivoting northeast across north central Nebraska
in advance of lead shortwave impulse which will continue to slide
northeast into eastern South Dakota this morning. This particular
complex should stay out of much of the CWA early this morning but
may skirt our far northwestern counties. Otherwise, scattered
showers and isolated thunderstorms continue to develop on nose of
30kt 850mb jet across northeastern Nebraska and should continue
through a good chunk of the morning. In addition, low dewpoint
depressions have led to some areas of patchy fog this morning but
this should improve after sunrise.
As the previous mentioned mid-level low moves over the Dakotas
this afternoon, the Pacific front will slowly slide east and
extend south through the central Dakotas and central Nebraska by
00z/Friday. Increasing southwesterly mid-level flow in advance of
the upper trough, in addition to south/southeasterly low level
flow should significantly increase deep layer shear by afternoon.
Million dollar question will be how much clearing, if any, we
will see by this afternoon in wake of morning showers and
thunderstorms. Most recent runs of the CAMs indicate a few rounds
of thunderstorms before synoptic front moves into the area late this
afternoon and mainly this evening. In any case, a few severe
storms seem quite possible across portions of our northwestern CWA
later this afternoon where deep layer shear is highest.
Showers and thunderstorms should continue through the overnight as
another mid-level impulse pivots northeast through the CWA and the front
slides through the forecast area. This activity will also be
aided by a southwesterly nocturnal low level jet. Some heavy rain
potential seems likely across southeast Nebraska where flash flood
guidance is lower due to recent heavy rains. Will need to keep a
close eye on this area as pcpn may linger into the day Friday.
Quiet weather is expected into Saturday with surface high pressure
building overhead. Light winds, highs in the mid 70s and clear
skies should combine for a very pleasant Saturday.
.LONG TERM...(Saturday night through Wednesday)
Issued at 214 AM CDT THU SEP 15 2016
Near zonal flow aloft is forecast through early next weak with
heights building toward Tuesday ahead of an approaching shortwave
trough. Strong low level warm air advection pattern sets up later
Tuesday with increasing pops into Wednesday and Thursday.
&&
.AVIATION...(06Z TAFS for KOFK...KLNK and KOMA.)
Issued at 1157 PM CDT WED SEP 14 2016
Conditions could deteriorate to LIFR levels at KOFK tonight, with
IFR possible at KOMA and KLNK, as ceilings drop and fog develops
across central and northeastern Nebraska. Patchy drizzle or very
light rain will also be possible overnight and into the early
morning hours. Ceilings and visibilities should rebound to MVFR
levels by early afternoon, however shower and thunderstorm chances
will increase into Thursday afternoon. For now, continued to omit TS
mention due to uncertainty in storm coverage and timing.
&&
.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&
$$
SHORT TERM...Kern
LONG TERM...Kern
AVIATION...KG
Area Forecast Discussion
National Weather Service SAN ANGELO TX
418 AM CDT THU SEP 15 2016
.SHORT TERM...
(Today and Tonight)
Afternoon heating combined with weak disturbances in southwest flow
aloft will be the main mechanism for isolated to scattered showers
and thunderstorms. Short range model HRRR indicate the best chance
of storms in the Big Country along and north of the I-20 corridor
with more isolated storms south. The main weather impact will be
localized flooding as precipitable waters are in the 1.40 to 1.75
range in a tropical-like environment.
Temperatures today will be similar to Wednesday with highs in the
upper 80s to around 90 and lows in the upper 60s to around 70.
.LONG TERM...
(Friday through Thursday)
Looks like a chance of rain through the weekend across much of West
Central Texas. The combination of weak upper level disturbances
moving northeast, afternoon and early evening instability and
abundant tropical moisture(PW values 1.5 to 1.75 inches) will
result in scattered showers and thunderstorms Friday and Saturday.
The best coverage of showers of storms will probably be across the
Big Country, northern Concho Valley and northern Heartland. The
storms will produce heavy rainfall, localized flooding and
dangerous lightning.
An upper level high pressure ridge will begin building across much
of Texas extending northeast into the mid Mississippi and Tennessee
valleys next week. This will bring a drying trend and warm
temperatures to West Central Texas. However, still keeping mainly
slight chance Pops going for Monday through Wednesday, mainly due to
some instability during the afternoon hours. Otherwise, upper level
forcing is weak and no significant front in the area. Highs will be
in the upper 80s to lower 90s with lows in the upper 60s to around
70.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 88 70 89 68 / 30 30 30 40
San Angelo 89 69 92 68 / 20 20 20 30
Junction 90 69 91 69 / 20 20 20 20
Brownwood 89 70 91 69 / 30 20 20 30
Sweetwater 87 69 89 68 / 30 30 30 50
Ozona 88 70 89 69 / 20 20 20 20
&&
.SJT Watches/Warnings/Advisories...
None.
&&
$$
04/21
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
357 AM CDT THU SEP 15 2016
.SHORT TERM...(Today and tonight)
Issued at 349 AM CDT Thu Sep 15 2016
The upper low appears to be moving into the northern Rockies per the
08z water vapor imagery. The better PVA looks to be occurring over
the NEB panhandle and SD while there may be some energy further
south along the TX/NM state line. At the surface, high pressure
remains over central and eastern KS but it continues to weaken and
any boundary is pretty hard to distinguish. Models and profiler data
show the stronger 850MB winds have set up from western KS into
central NEB. Some speed convergence and isentropic upglide may be
helping some elevated showers that have formed just north of the
forecast area.
For today and tonight, models show plenty of moisture in place for
more precip and there is not a great deal of inhibition to
convection with modest instability progged by the afternoon. Think
there are two potential sources of precip. First is the possibility
for elevated showers and thunderstorms this morning. Models show
some isentropic upglide over the area but it does not appear to be
very deep or very strong. Because of this, I`m not sure how
widespread shower activity may be this morning. The HRRR is showing
only isolated precip. With this in mind, think precip may remain
more isolated to scattered and will carry a chance POP through the
morning and adjust if it becomes more obvious storms will be more
widespread. The second chance for precip, and what appears to be the
better chance of the two, looks to be overnight tonight. The
thinking is that storms will develop to the west within the surface
trough axis and modest low level convergence and form into a
convective cluster moving east across the forecast area. The NAM
which has no inhibition for a boundary layer parcel, appears to be a
little to eager to generate precip through the day. If there was a
better defined wave over west TX, I may be inclined to follow the
NAM more closely. But the ARW and NMM seem to favor storms forming
to the west late in the afternoon and moving across the area
overnight. Confidence in timing storms is not that high because of a
moist unstable airmass in place and the lack of a strong forcing
mechanism. So there is a chance for showers and storms just about
any time of day.
Since the forecast anticipates storm development to the west of the
forecast area, think the potential for severe storms is limited.
Models once again show weak 0-6km shear. So the best chance for
severe weather may be as storms develop with peak instability from
day time heating. There may be a wind risk if storms organize into a
linear MCS. Will have to keep an eye on this. Perhaps the greater
hazard will be additional heavy rainfall. Models show PWs remaining
in the 1.5 to 2 inch range. So storms are likely to be efficient
rain producers once again. Since overall confidence in how storms
will evolve over the next 24 hours is low, it`s difficult to
pinpoint where the heavy rainfall may occur. So will not issue a
flash flood watch at this time, but it may be something the day
shift can consider.
Have not made any big changes to the temp forecast for today. Model
progs of 850MB temps around 17C and no significant change to the
airmass support the previous forecast of highs around 80. Southern
winds and the moist airmass holding in place overnight should lead
to lows remaining in the mid 60s.
.LONG TERM...(Friday through Wednesday)
Issued at 349 AM CDT Thu Sep 15 2016
By Friday, the upper level trough will be located over the Dakotas
and forecast to move northeast through the day. By early afternoon,
a surface front will be located near northeast Kansas and will
continue to progress across the area throughout the afternoon and
evening. With a front in the area and a moderately unstable airmass
in place, thunderstorms may develop along the boundary in the
afternoon. Shear values indicate organized convection is possible,
so any storm that forms Friday afternoon has the potential to be
strong. With storms forecast in earlier periods, and PWATS over 1.5
inches Friday afternoon, heavy rain will be possible with any storm
and may lead to localized flooding.
The GFS is still the slowest to exit precipitation out of the area
Saturday morning keeping chances for storms mainly located to east
central Kansas Saturday morning/afternoon. High pressure over the
area looks to keep Saturday night dry before a shortwave is progged
to move over the area Sunday bringing chances back. From here,
upper level ridging is forecast with some weak disturbances bringing
slight chances for precipitation through the end of the period.
High temperatures stay near climatology for the beginning of the
period in the upper 70s and low 80s before warming up slightly at
the start of the work week. Lows generally stay in the lower 60s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1148 PM CDT Wed Sep 14 2016
Minor changes to previous forecast. Some clearing between
scattered lower cloud and cirrus allowing for some drop in
visibilities already. Though winds still look to be increasing in
the top of the boundary layer, mixing looks to be weak enough for
some MVFR to IFR BR to form. Have kept VCTS going around 15Z but
confidence in timing and persistence of convection remains low.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Heller
AVIATION...65
Area Forecast Discussion
National Weather Service GLASGOW MT
916 AM MDT THU SEP 15 2016
.SHORT TERM...for northeast Montana...today through Sat...
Update: Latest radar image along with the latest HRRR run support
continued convective development along the lower Yellowstone
valley and adjoining areas. Thus updated to increase pops there,
also spread isolated pops westward given ongoing light shower
activity west of Glasgow. Temps and sky were unchanged. Gilchrist
Previous discussion: Upper low over western Wyoming expected to
clip eastern Montana as it lifts into North Dakota today. Surface
boundary already in western North Dakota and will linger through
the day, providing a focus for shower and thunderstorm
development.
Overnight some weak shortwave energy slides through the northwest
flow out of Alberta. Mainly expect an area of cloud to move across
the region with this wave.
Friday and Saturday will be transition days as the flow backs to
the west in response to a strong jet pushing through the north
Pacific. Dry and warm conditions expected, especially on Saturday
when flow becomes downslope dominated. Ebert
.LONG TERM...Sat night through Thu...
The extended forecast period begins with a very general zonal flow
aloft and a tighter pressure gradient in place.
Saturday night through Sunday night: Model consensus indicates
that an abrupt cold front with gusty winds will push through NE
Montana. Should be a relatively dry cold front with only isolated
or scattered rain showers possible. West winds of 25 to 35 mph
will also be possible, which indicates that a Lake Wind Advisory
may be needed for Fort Peck Lake.
Monday through Tuesday morning: A brief period of short-wave
ridging will keep precipitation away from most of the region -
especially south of US Highway 2.
Tuesday night and beyond: A more active weather pattern is
expected as the flow aloft turns more from the SW and a low
pressure system digs through the northern Rockies. Forecast
confidence for any further details remain characteristically vague
this far out due to significant model disagreements. Tried
basically to paint a broad picture of a wetter weather pattern for
this time frame.
BMickelson
&&
.AVIATION...
FLIGHT CATEGORY: VFR to MVFR
SYNOPSIS: A circulating low pressure system with its center over
the western Dakotas will push periods of rain showers and a few
thunderstorms through the region today. KSDY, KGDV, and points E
and SE could experience ceilings of 6000 feet with isolated
thunderstorms between 15Z and 00Z today. Where Thunder does occur
brief reduction in visibility could reach MVFR conditions.
WINDS: Northeast around at 5 to 15 kts this afternoon, calming to
less than 10 kts overnight.
BMickelson/GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1127 AM EDT Thu Sep 15 2016
.SYNOPSIS...
Tropical system Julia will linger over the southeast coast today
into Friday with the deeper moisture associated with the system
expected to remain mostly over the coastal waters. Meanwhile, a back
door cold front will settle southward through tonight as high
pressure moves over New England. Another cold front is expected to
approach the Western Carolinas late in the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1115 AM, The latest mesoscale/convection-allowing models
continue the trend of backing off of convective chances for the high
terrain later today. Forecast soundings do appear quite suppressed,
and it appears if anything does fire, it will be most likely in the
along and SW of the Balsams. Very little change was made to pops,
although any mention above slight chance has been removed. One
recent development in the HRRR has been to allow a few popcorn
showers to develop over the Piedmont within a convergence/confluence
zone just east of the forecast area. Since this is a relatively new
development, will hold off on introducing any slight chances to the
I-77 corridor, and revisit that for the 18Z update. Temps will once
again increase to the upper 80s/lower 90s across much of the
Piedmont and foothills, with mid-80s expected in the lower mtn
valleys.
Otherwise, the center of circulation of tropical system Julia
remains roughly due east of Savannah GA, with all attendant
convection wrapping mainly over the coastal and offshore waters east
of the system. A back door frontal boundary will get a better push
southward across the forecast area later tonight as the surface high
center builds over New England. This will permit improving low level
easterly flow and associated better moisture to gradually spread
southward along the northern Blue Ridge overnight. However, the
deeper moisture and stronger upslope will remain generally north of
the area through the near term. Expect another night of well above
climo minimum temperatures.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
At 200 AM Thursday: On Friday morning an upper ridge will extend
from FL to the Great Lakes, while a positively tilted upper ridge
will extend from CA to ND. By Saturday the eastern ridge becomes
positively tilted as well, extending from FL to the Gulf Stream off
the East Coast, while the western trough starts to go out of phase,
with it`s southern portion remaining over CA, and it`s northern
portion reaching the Great Lakes. By Sunday morning the ridge
flattens and retrogresses over the Gulf States, while the northern
trough reached Quebec, and a northern ridge reaches MN and Ontario.
meanwhile, closed upper low meanders southwest of CA.
At the surface, on Friday morning a surface ridge will be along the
eastern seaboard, and the Western Carolinas and Northeast Georgia
will be between a stalled surface front in VA and Tropical System
Julia off the South Carolina Coast. The models suggest moisture
associated with Julia will spread north and inland to our area
between Saturday morning and Sunday morning, but WPC forecasts keep
precipitation closer to the coast. Meanwhile a cold front will
slowly approach our area from the northwest, crossing the OH river
valley by Sunday. Initially forecast precipitation be kept in the
piedmont nearer to affects from Julia, then precipitation will be
allowed to spread over the Blue Ridge in advance of the front, with
light precipitation over the whole area by Friday night. Temperatures
will exhibit a reduced diurnal trend ostensibly due to cloud cover
and moisture.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
At 200 AM Thursday: On Sunday morning a flat upper ridge will extend
from TX to the NC Coast, while nearly zonal flow aloft remains over
the northern tier of if the USA, and upper troughs and ridges cross
Canada. By Tuesday the southern ridge retrogrades and amplifies over
the Southern Plains, while an upper trough amplifies off the East
Coast. By Wednesday the upper ridge progresses more or less to TN,
while the eastern trough moves well offshore, and an upper trough
amplifies along the west coast.
At the surface, on Sunday a cold front approaches our area from the
northwest, while Tropical System Julia, or remains thereof, appears to
meander off the SC coast. The models differ on when the front
crosses our area, with the GFS brining it off the cast on Monday,
and the ECMWF stalling it just to our south on Tuesday. Both models
bring a ridge of high pressure down the Eastern Seaboard by mid weak
in the wake of the front, but the ECMWF solutions would support
lingering precipitation to the north of the stalled boundary, which
the current WPC precipitation forecast appears to support. With only
weak isentropic upglide and upslope flow depicted by the ECMWF,
excessive precipitation is not supported at this time. Temperatures
will continue to exhibit a reduced diurnal trend due to persistent
clouds and moisture per the ECMWF/WPC solutions.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
At KCLT: Early morning low clouds are flirting with areas just east
of the airfield, but sunrise should limit the westward expansion of
the stratus deck. Will hint at low clouds for the morning hours but
keep conditions VFR. Otherwise, expect steady NE winds with
occasional low end gusts with mixing this afternoon. Drier air
wrapping west around the Julia circulation should keep the terminal
precipitation free this afternoon. Another episode of nearby low
clouds will be possible in NE flow tonight, and MVFR cigs will be
advertised after 09Z.
Elsewhere: The potential for low clouds and fog remains a bit
elevated across the mountain valleys where winds are light and
boundary layer moisture is a touch greater than elsewhere. Any
restrictions should be quite brief in the valleys and will probably
not form across the foothills given the trends on the IR satellite
low cloud product. Winds will be mainly NE at the foothill sites,
and mainly NW at KAVL. Isolated shower chances will be greatest over
the higher ridge tops but still too low to mention at KAVL.
Outlook: The moisture associated with tropical system Julia will
need to be closely monitored through Friday. Otherwise, a back door
cold front will settle south across the region late tonight. Moist
easterly flow may redevelop behind the front. The chance of
restrictions will increase, especially during the morning hours from
Friday through the weekend.
Confidence Table...
15-21Z 21-03Z 03-09Z 09-12Z
KCLT High 100% High 100% High 100% High 84%
KGSP High 100% High 100% High 100% High 95%
KAVL High 100% High 100% High 100% Low 57%
KHKY High 100% High 100% High 100% High 84%
KGMU High 100% High 100% High 100% High 95%
KAND High 100% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...HG
NEAR TERM...HG/JDL
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...HG
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
945 AM EDT Thu Sep 15 2016
.UPDATE...
Issued at 945 AM EDT THU SEP 15 2016
The latest trends and RAP data suggest the stratus deck over the
northern most part of the forecast area will linger into the
afternoon. The southern edge of the stratus is lifting and
eroding, and this trend will continue. Following these ideas have
made adjustments to the hourly sky and temperature forecast grids,
with a slower temperature rise where the stratus is expected to
linger.
UPDATE Issued at 634 AM EDT THU SEP 15 2016
Tricky forecast for the near term with fog/stratus issues this
AM. Fog channel has continued to show an area of of low stratus
that was progressing more SW most of the night generally along and
north of the I-64 corridor. However the stratus has started to
trend more south over the past hour. This is likely tied to the
left over boundary that is likely within the vicinity. Models have
struggled all night to latch on to this, but overall best model has
been the RAP. This is also playing havoc with hourly temps this
morning as they rise with the progression of the low deck. Made
updates to the Sky grids to establish a trend, with mostly hand
edits considering the lack of model help including the Consshort.
Also Amd JKL/SJS to better deal with the latest trends. Also
adjusted hourly temps to reflect the warming trends under the
stratus.
&&
.SHORT TERM...(Today through Friday)
Issued at 339 AM EDT THU SEP 15 2016
In terms of the upper levels a broad upper level ridge axis will
swing east across the region. This ridge axis will progress east
into the Mid Atlantic by Friday, as a upper level low ejects into
the Upper Plains. Surface wise we will see a high pressure to our
north across the Great Lakes progress east into the Mid Atlantic
by tonight into early Friday.
Sensible weather wise this morning we will see a thin ribbon of
low level stratus drift SW across the far north. Otherwise most
will see mostly clear skies with a few high clouds. This afternoon
would suspect some CU would develop along with high clouds. The
airmass does modify with the weak boundary, as 850mb temps
dropping into the 16 to 17C range. Therefore did not go as hot as
yesterday, but we will still see mid to upper 80s. Tonight will
remain mostly clear and calm, so typical valley fog issues seem
reasonable. Friday the airmass makes a recovery as heights rise,
850 mb temps rise into the 18 to 19C range and return flow sets
in. Therefore did opt to go for a few 90s for highs in the
afternoon. Also return flow could be enough to pop off isolated
storms in the far east, and this was hinted at in the GFS and
several CAMs. While these storms will be isolated in nature they
could produce heavy rainfall given little to no steering flow.
.LONG TERM...(Friday night through Wednesday)
Issued at 338 AM EDT THU SEP 15 2016
Our recent stretch of dry weather looks to come to a temporary
halt this weekend as a shortwave trough moves across the central
plains and into the Ohio river valley. A corresponding cold front
will accompany this feature as it tracks across the region.
Models are slowly coming into better agreement on the progression
of this feature, but there are still some slight differences,
mostly involving precipitation chances Friday night into early
Saturday. Showers and storms will likely form ahead of the
boundary late Friday and drop south and east across
Indiana/Ohio/Northern Kentucky Friday night into early Saturday.
This convection will likely outrun the existing cold front and
fade away as it sinks southeast into eastern Kentucky. How
quickly this happens remains a bit cloudy, but there will be at
least some small chances for showers and storms arriving as early
as Saturday morning with the best chances to the north and west,
and fading as you head southeast. After this early day activity,
looks like activity will reorganize back to the northwest along
the approaching front, which may spell a break from any showers
or storms through Saturday afternoon/evening.
The front will then work south and east into and across
eastern Kentucky late Saturday night through Sunday. This will
likely be our period for highest rain chances as operational
models all agree on a wet period on Sunday. Overall rainfall
totals look to be on the light side with under a quarter of an
inch for most areas. Certainly won`t be enough rainfall to offset
our deficits we have seen the past several weeks.
The thing that has changed is the front is much more progressive
in both the GFS and ECMWF and it looks like rain chances will
quickly diminish heading into Sunday evening as the front exits
south. The idea of a ECMWF southern stream wave is much more
suppressed to the south, so it looks like we can dry out the
forecast by late Sunday night and Monday. While there remains
some uncertainty into the evolution of the upper level pattern
next week, it looks fairly certain we will enter another
prolonged dry period which will last through the week. In fact,
the ECMWF solution has a very strong ridge over the eastern US
for much of the week with 850mb temps approaching +21C by
Wednesday and Thursday and lasting into the following weekend. If
this were to occur, we`d be looking at another period of well
above normal temperatures, approaching record high for at least a
few days.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 648 AM EDT THU SEP 15 2016
Biggest issue this AM has been the fog/stratus deck that continues to
progress south. It has been difficult to establish a trend given
the change in direction over the past hour or 2. Right now only
expect this stratus to only affect SYM/JKL/SJS, but some of these
sites are or could see airport minimums reached. This is likely
riding along a left over boundary based on wind shift. Overall the
only decent model support has been the RAP and therefore leaded
toward this for some of the trends. Would think that this deck
will burn off by late morning and this matches the RAP trends
right now. Otherwise high clouds have moved in and would suspect
afternoon VFR CU would also develop. Fog may be a issue in the
valleys but should burn off through the morning. Winds will remain
light through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...DJ
LONG TERM...KAS
AVIATION...DJ
Area Forecast Discussion
National Weather Service Melbourne FL
11 AM EDT THU SEP 15 2016
.DISCUSSION...
A weak surface trough has pushed into northern sections
(Lake/Volusia) assocd with a band of stratus and a wind shift out of
the NW but speeds are light, less than 10 mph. Have shaved PoPs a
little lower across north Lake/northern Volusia but agree that the
focus for storms will be over metro Orlando/Cape this afternoon.
Expect this boundary to interact with the east coast sea breeze as
it pushes inland along with outflows moving in from the west. Like
the depiction of our local 6km WRF showing mid to late aftn storms
pushing east across Orlando/Cape. The Cape and Tampa soundings show
2.0-2.2" precipitable water and with numerous boundaries and
sufficient surface heating, the HRRR has looked too low with its
coverage of storms. Temps aloft remain quite warm with +10C at 700
mb and -5C at 500 mb so severe weather is not expected. And the
winds aloft are not as strong so do not expect to see as many bowing
structures as we saw yesterday. Lightning and heavy rain will be the
primary threats.
&&
.AVIATION...
IFR/MVFR stratus from MCO north will gradually lift as mixing
heights increase by 16Z or so. Light offshore flow will turn onshore
in a sea breeze at all coastal terminals this afternoon. Boundary
collisions will produce scattered to numerous shra/tsra across north
and interior sections so TEMPO groups look fine from MCO-SFB-DAB.
&&
.MARINE...
Made some adjustments to winds as a weak frontal trough has pushed
into the northern marine zone (adjacent to Volusia county). A light
N/NW flow there will turn NE in a sea breeze this afternoon.
Elsewhere, W/SW flow will turn E/SE in a sea breeze from the Cape
southward. Seas are generally 2 feet this morning but a long period
swell from the east is forecast to build this afternoon and tonight
with seas reaching up to 4 feet offshore. Low coverage of
showers/storms during the day over the Atlantic then storms should
push offshore early this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 90 75 89 76 / 60 30 50 20
MCO 90 75 91 75 / 60 30 50 20
MLB 90 76 89 76 / 50 30 40 20
VRB 89 76 89 76 / 30 20 40 20
LEE 89 75 91 75 / 50 20 50 20
SFB 90 75 91 75 / 60 30 50 20
ORL 90 75 91 75 / 60 30 50 20
FPR 90 76 89 76 / 30 20 30 20
&&
.MLB Watches/Warnings/Advisories...
FL...None.
AM...None.
&&
$$
Kelly/Bragaw
Area Forecast Discussion
National Weather Service Omaha/Valley NE
629 AM CDT THU SEP 15 2016
.SHORT TERM...(today through Saturday)
Issued at 214 AM CDT THU SEP 15 2016
Latest water vapor imagery and RAP 500mb analysis shows mid-level
low opening as it lifts northeast over the Northern Rockies and
toward the Northern Plains. Ahead of this, strong low-level moist
advection continues early this morning with surface dewpoints
currently in the lower to mid 60s with upper 60s forecast by this
afternoon. This is ahead of a fairly weak Pacific front which per
latest surface analysis, extends south from low pressure over
southwest North Dakota into far western Nebraska and eastern
Colorado. Early morning regional radar mosaic shows a thunderstorm
complex quickly pivoting northeast across north central Nebraska
in advance of lead shortwave impulse which will continue to slide
northeast into eastern South Dakota this morning. This particular
complex should stay out of much of the CWA early this morning but
may skirt our far northwestern counties. Otherwise, scattered
showers and isolated thunderstorms continue to develop on nose of
30kt 850mb jet across northeastern Nebraska and should continue
through a good chunk of the morning. In addition, low dewpoint
depressions have led to some areas of patchy fog this morning but
this should improve after sunrise.
As the previous mentioned mid-level low moves over the Dakotas
this afternoon, the Pacific front will slowly slide east and
extend south through the central Dakotas and central Nebraska by
00z/Friday. Increasing southwesterly mid-level flow in advance of
the upper trough, in addition to south/southeasterly low level
flow should significantly increase deep layer shear by afternoon.
Million dollar question will be how much clearing, if any, we
will see by this afternoon in wake of morning showers and
thunderstorms. Most recent runs of the CAMs indicate a few rounds
of thunderstorms before synoptic front moves into the area late this
afternoon and mainly this evening. In any case, a few severe
storms seem quite possible across portions of our northwestern CWA
later this afternoon where deep layer shear is highest.
Showers and thunderstorms should continue through the overnight as
another mid-level impulse pivots northeast through the CWA and the front
slides through the forecast area. This activity will also be
aided by a southwesterly nocturnal low level jet. Some heavy rain
potential seems likely across southeast Nebraska where flash flood
guidance is lower due to recent heavy rains. Will need to keep a
close eye on this area as pcpn may linger into the day Friday.
Quiet weather is expected into Saturday with surface high pressure
building overhead. Light winds, highs in the mid 70s and clear
skies should combine for a very pleasant Saturday.
.LONG TERM...(Saturday night through Wednesday)
Issued at 214 AM CDT THU SEP 15 2016
Near zonal flow aloft is forecast through early next weak with
heights building toward Tuesday ahead of an approaching shortwave
trough. Strong low level warm air advection pattern sets up later
Tuesday with increasing pops into Wednesday and Thursday.
&&
.AVIATION...(12Z TAFS for KOFK...KLNK and KOMA.)
Issued at 623 AM CDT THU SEP 15 2016
CIGs will lower to MVFR category at KLNK/KOMA this morning and
remain IFR at KOFK. In addition a few showers are possible at all
3 sites through at least mid morning. Some thunder is possible
this morning, especially at KOFK but will lead out of KOMA/KLNK
due to limited confidence. By mid-afternoon CIGS should improve
to VFR at all 3 sites. TSRA may develop late this afternoon and
impact the OFK TAF site first into early evening, and then
KOMA/KLNK late evening into the early morning hours and have
included a tempo group for all 3 sites.
&&
.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&
$$
SHORT TERM...Kern
LONG TERM...Kern
AVIATION...Boustead
Area Forecast Discussion
National Weather Service Charleston WV
1000 AM EDT THU SEP 15 2016
.SYNOPSIS...
High pressure passes to the north today. Next cold front arrives
Sunday. High pressure early next week brings only slightly cooler
weather.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1000 AM Thursday...
Low stratus still hanging tough along and west of the I-79
corridor. Relied heavily on the HRRR to update sky grids and
linger for a couple more hours. Still expecting it to break up
late this morning. Also used a HRRR/MET blend for highs
today...going a bit cooler under the current cloud shield.
As of 130 AM Thursday...
A wavy thin line of low stratus in the vicinity of the decaying
frontal boundary will meander across the area into the morning
hours before mixing out. We remain sort of between synoptic
surface features today with high pressure anchored over the
Northeast and a tropical low along the SE coast. There will be
some slightly cooler air aloft which combined with healthy cu...should
shave a few degrees off from yesterdays numbers. A lee side trof
over the W VA may provide enough convergence for a few shra/tsra
over Nicholas/Pocahontas Counties this afternoon...otherwise have
a dry fcst coded up.
Low level moisture banks up against the mountains on developing SE
flow for quite a bit of stratus overnight in the E slopes and
perhaps some spotty dz or light shra.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 420 AM Thursday...
High pressure moves off the New England coast Friday, well to the
northeast of the forecast area, which allows a return south to
southeast flow of warmer and more humid air to develop. There may
be an upslope shower along the eastern slopes of the WV mountians.
A cold front approaching from the west will give rise to an
increasing chance for showers and thunderstorms this
weekend. A weak lead upper level short wave trough could bring
showers into the area as early as overnight Friday night. Beyond
that, timing will be tough, as several more weak ripples move
through the upper level southwest flow, ahead of the main, better
defined short wave trough that pushes the cold front through the
area sometime on Sunday.
Temperatures at or a little above previous package based on latest
guidance trends.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 827 AM Tuesday...
Generally used WPC thinking with some tweaks. Main changes from
WPC are PoPs near the end of the period. WPC Frontal Progs for
Days 6 & 7 suggest high pressure will be in charge across the
region. However...WPCGuide grids keep low PoPs across the area
well behind the front. Expect airmass should be too dry to support
precipitation...so have left region dry from late Monday through
Tuesday.
End result will be a cold front should approach the area Saturday
and Saturday night...before pushing southeast Sunday into Sunday
Night. High Pressure should then take control Monday and remain
in place for Tuesday.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
As of 1000 AM Thursday...
IFR hanging on longer than forecast, so have updated grids and
TAFs. Rather low confidence on exactly when this will break up
over the next couple hours.
VFR conditions return late this morning after any low stratus and
fog mix out with a healthy cu field thru the aftn. Tonight low
level SE flow develops which should keep low stratus banked up
against the mountains...probably affecting KBKW with IFR CIGS just
beyond the taf period.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Timing of low stratus erosion differ.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 12 13 14 15 16 17 18 19 20 21 22 23
EDT 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
CRW CONSISTENCY M M H H H H H H H H H M
HTS CONSISTENCY M M M M H H H H H H H M
BKW CONSISTENCY H H H H H H H H H H H M
EKN CONSISTENCY H H H H H H H H H H H M
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY L L M H H H H H H H H M
AFTER 12Z FRIDAY...
May get IFR in isolated morning valley fog late this week. IFR
possible in showers/storms with cold front this weekend.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...TRM/30
NEAR TERM...MZ/30
SHORT TERM...TRM
LONG TERM...JSH
AVIATION...MZ/30
Area Forecast Discussion
National Weather Service SAN ANGELO TX
637 AM CDT THU SEP 15 2016
.AVIATION...
/12Z TAFS/
Occasional MVFR light fog and ceilings will rise to VFR late
morning. Added a VCTS at KABI mid-afternoon to early evening for
scattered thunderstorms. Southeast to south winds will otherwise
prevail at 10 KTS or less.
&&
.PREV DISCUSSION... /issued 418 AM CDT THU SEP 15 2016/
SHORT TERM...
(Today and Tonight)
Afternoon heating combined with weak disturbances in southwest flow
aloft will be the main mechanism for isolated to scattered showers
and thunderstorms. Short range model HRRR indicate the best chance
of storms in the Big Country along and north of the I-20 corridor
with more isolated storms south. The main weather impact will be
localized flooding as precipitable waters are in the 1.40 to 1.75
range in a tropical-like environment.
Temperatures today will be similar to Wednesday with highs in the
upper 80s to around 90 and lows in the upper 60s to around 70.
LONG TERM...
(Friday through Thursday)
Looks like a chance of rain through the weekend across much of West
Central Texas. The combination of weak upper level disturbances
moving northeast, afternoon and early evening instability and
abundant tropical moisture(PW values 1.5 to 1.75 inches) will
result in scattered showers and thunderstorms Friday and Saturday.
The best coverage of showers of storms will probably be across the
Big Country, northern Concho Valley and northern Heartland. The
storms will produce heavy rainfall, localized flooding and
dangerous lightning.
An upper level high pressure ridge will begin building across much
of Texas extending northeast into the mid Mississippi and Tennessee
valleys next week. This will bring a drying trend and warm
temperatures to West Central Texas. However, still keeping mainly
slight chance Pops going for Monday through Wednesday, mainly due to
some instability during the afternoon hours. Otherwise, upper level
forcing is weak and no significant front in the area. Highs will be
in the upper 80s to lower 90s with lows in the upper 60s to around
70.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 88 70 89 68 / 30 30 30 40
San Angelo 89 69 92 68 / 20 20 20 30
Junction 90 69 91 69 / 20 20 20 20
Brownwood 89 70 91 69 / 30 20 20 30
Sweetwater 87 69 89 68 / 30 30 30 50
Ozona 88 70 89 69 / 20 20 20 20
&&
.SJT Watches/Warnings/Advisories...
None.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
633 AM CDT THU SEP 15 2016
...AVIATION UPDATE...
.SHORT TERM...(Today and tonight)
Issued at 349 AM CDT Thu Sep 15 2016
The upper low appears to be moving into the northern Rockies per the
08z water vapor imagery. The better PVA looks to be occurring over
the NEB panhandle and SD while there may be some energy further
south along the TX/NM state line. At the surface, high pressure
remains over central and eastern KS but it continues to weaken and
any boundary is pretty hard to distinguish. Models and profiler data
show the stronger 850MB winds have set up from western KS into
central NEB. Some speed convergence and isentropic upglide may be
helping some elevated showers that have formed just north of the
forecast area.
For today and tonight, models show plenty of moisture in place for
more precip and there is not a great deal of inhibition to
convection with modest instability progged by the afternoon. Think
there are two potential sources of precip. First is the possibility
for elevated showers and thunderstorms this morning. Models show
some isentropic upglide over the area but it does not appear to be
very deep or very strong. Because of this, I`m not sure how
widespread shower activity may be this morning. The HRRR is showing
only isolated precip. With this in mind, think precip may remain
more isolated to scattered and will carry a chance POP through the
morning and adjust if it becomes more obvious storms will be more
widespread. The second chance for precip, and what appears to be the
better chance of the two, looks to be overnight tonight. The
thinking is that storms will develop to the west within the surface
trough axis and modest low level convergence and form into a
convective cluster moving east across the forecast area. The NAM
which has no inhibition for a boundary layer parcel, appears to be a
little to eager to generate precip through the day. If there was a
better defined wave over west TX, I may be inclined to follow the
NAM more closely. But the ARW and NMM seem to favor storms forming
to the west late in the afternoon and moving across the area
overnight. Confidence in timing storms is not that high because of a
moist unstable airmass in place and the lack of a strong forcing
mechanism. So there is a chance for showers and storms just about
any time of day.
Since the forecast anticipates storm development to the west of the
forecast area, think the potential for severe storms is limited.
Models once again show weak 0-6km shear. So the best chance for
severe weather may be as storms develop with peak instability from
day time heating. There may be a wind risk if storms organize into a
linear MCS. Will have to keep an eye on this. Perhaps the greater
hazard will be additional heavy rainfall. Models show PWs remaining
in the 1.5 to 2 inch range. So storms are likely to be efficient
rain producers once again. Since overall confidence in how storms
will evolve over the next 24 hours is low, it`s difficult to
pinpoint where the heavy rainfall may occur. So will not issue a
flash flood watch at this time, but it may be something the day
shift can consider.
Have not made any big changes to the temp forecast for today. Model
progs of 850MB temps around 17C and no significant change to the
airmass support the previous forecast of highs around 80. Southern
winds and the moist airmass holding in place overnight should lead
to lows remaining in the mid 60s.
.LONG TERM...(Friday through Wednesday)
Issued at 349 AM CDT Thu Sep 15 2016
By Friday, the upper level trough will be located over the Dakotas
and forecast to move northeast through the day. By early afternoon,
a surface front will be located near northeast Kansas and will
continue to progress across the area throughout the afternoon and
evening. With a front in the area and a moderately unstable airmass
in place, thunderstorms may develop along the boundary in the
afternoon. Shear values indicate organized convection is possible,
so any storm that forms Friday afternoon has the potential to be
strong. With storms forecast in earlier periods, and PWATS over 1.5
inches Friday afternoon, heavy rain will be possible with any storm
and may lead to localized flooding.
The GFS is still the slowest to exit precipitation out of the area
Saturday morning keeping chances for storms mainly located to east
central Kansas Saturday morning/afternoon. High pressure over the
area looks to keep Saturday night dry before a shortwave is progged
to move over the area Sunday bringing chances back. From here,
upper level ridging is forecast with some weak disturbances bringing
slight chances for precipitation through the end of the period.
High temperatures stay near climatology for the beginning of the
period in the upper 70s and low 80s before warming up slightly at
the start of the work week. Lows generally stay in the lower 60s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 633 AM CDT Thu Sep 15 2016
Forecast soundings from the NAM and GFS show the boundary layer
mixing out by 15Z, so have conditions improving by then. However
the RAP soundings keep the boundary layer saturated for a little
longer. Will monitor trends this morning and make adjustments as
needed. Confidence in TS impacting the terminals today is to low
to include a mention if the forecast at this time. Think TS may be
more likely late in the forecast period, but will let the next
shift evaulate the latest model data before adding it to the
forecast. So once the fog and stratus clear out, think VFR
conditions should prevail for much of the day.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Heller
AVIATION...Wolters
Area Forecast Discussion
National Weather Service La Crosse WI
145 PM CDT Thu Sep 15 2016
.SHORT TERM...(Tonight through Friday Night)
Issued at 145 PM CDT Thu Sep 15 2016
Deep/vigorous closed low and trough over the entering the Northern
Plains from MT/WY per latest water vapor imagery/RAP 500mb analysis.
Southwest flow ahead of this trough with embedded weak shortwave
activity was interacting with higher precipitable water
values/CAPE...producing some thunderstorm activity across
southwestern MN. Weaker showers were popping out ahead of
this...west of the Mississippi River on eastern fringe of increasing
850mb moisture transport. Otherwise...temperatures this afternoon
across the local area were hovering near seasonal normals in the
70s.
For tonight...latest HRRR convective allowing model....which was
handling convection best across southwest MN...take this complex of
storms and marches it into southeast MN/northeast IA by early this
evening and then across the rest of the area later this
evening/overnight. Latest RAP/NAM showing respectable amount of
CAPE in the 1000-1500J/kg range mainly south of I-90 but bulk shear
was lacking...generally hovering in the 20-25kt range. Thinking we
could see mainly pulse type/multicellular mode storms with a few of
the stronger storms capable of producing some sub-severe hail and
wind gusts. With higher precipitable water values increasing into to
around 1.5 inches...these storms will also be capable of heavier
rainfall. Not anticipating any flooding threat as these storms will
be fairly progressive in nature.
Mid-level low/trough pushes a cold front through the area Friday but
with ongoing convection/cloud cover/less cape and lack of good
convergence along the front and mid-level pv forcing heading north
of the area...not anticipating any severe threat. Main threat again
would be some heavier downpours and localized gusty winds.
A few lingering showers/isolated storms still possible mainly east
of the Mississippi River Friday evening...but then convection
expected to clear the area after midnight.
.LONG TERM...(Saturday through Thursday)
Issued at 145 PM CDT Thu Sep 15 2016
Cooler/drier air overspreads the area on Saturday. Given cyclonic
mid-level flow/cooler air aloft...expecting a fair amount of cumulus
development...mainly along/north of I-94. Also kept a small chance
of showers across Taylor county in north central WI. Look for highs
ranging from the upper 60s to the lower 70s.
Ridge of high pressure will provide a pleasant Sunday with highs
topping off in the 70s.
High-zonal mid-level flow will bring a trough across the Northern
Plains Sunday night with warm air advection taking place into our
area. Latest GFS/ECMWF showing some hint of light shower activity
pushing in...but not expecting anymore than isolated coverage.
A cold front slides through the area for Monday into Monday night
for a chance of showers and thunderstorms. May have to keep an eye
on this for a possible severe treat with GFS/EC showing 1500-
3000J/kg of MUCAPE and 0-3km bulk shear of 30-40kt.
Looks like another chance of showers and thunderstorms for Wednesday
into Thursday as both the GFS/ECMWF showing low pressure/warm front
pushing into the region.
Temperatures from Monday through Thursday look to be right around
or slightly above normal with highs in the 70s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1206 PM CDT Thu Sep 15 2016
Good VFR expected thru the afternoon in S-SE gradient flow and
deeper diurnal warming/mixing keeping the lowest clouds sct and
mostly in the 3500-4500 ft range.
By this evening, deeper moisture arrives, along with some
instability and deeper layered forcing/lift. Rounds of SHRA/TSRA
looking to move across the area much of tonight thru Friday. First
round expected to move into SE MN early this evening, then into the
KLSE area late this evening. However, if ongoing convection over SW
MN/NW IA takes more of a right turn, SHRA/TSRA could be in the KRST
area late this afternoon then into KLSE early this evening. Present
convection should lift NE of the area and trended TAFs toward the
early evening arrival at KRST and later evening arrival at KLSE.
MVFR cigs/vsbys with lcl IFR cigs/vsbys in stronger TSRA and rain
cores. Much uncertainty after the first round of SHRA/TSRA goes by
after 08z-10z tonight into Fri morning. Trended the 08-10z thru 15z
period with VCSH and MVFR cigs/vsbys until convective details become
clearer. With diurnal warming/mixing carried VFR after 15z Wed for
now.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...RRS
Area Forecast Discussion
National Weather Service Dodge City KS
249 PM CDT THU SEP 15 2016
.SHORT TERM...(This evening through Friday)
Issued at 203 PM CDT Thu Sep 15 2016
The short term convective allowing models, specifically the WRF
runs have shifted their solutions more toward what the HRRR had
been forecasting through the day in terms of convection. That
keeps the bulk of the storm initiating mid afternoon across
eastern colorado, as just isolated cells, but growing upscale into
north west and northcentral Kansas including the I-70 corridor by
mid evening). These storms will be initiating along the weak cold
front/surface convergence zone.
The aforementioned cold front will move into the area tonight,
probably reaching the southeast 1/3 or so of the DDC forecast
area by midday Friday. This will act to decrease highs by around
10 degrees from Today as well as act as a convergence zone for
potential late day surface based convection again on Friday. In
either case, the set up in weak opt moderate CAPE/instability and
very weak shear in the absence of an jets.
.LONG TERM...(Friday night through Thursday)
Issued at 203 PM CDT Thu Sep 15 2016
The best chance for weekend precipitation appears late Saturday
or Saturday night with a signal in the GFS of elevated shower and
thunderstorms set of by a moderate shortwave in the westerlies.
Otherwise, a mainly zonal upper flow and overall dry regime is in
place for the medium to extended period. A warming trend is also
forecast, with models and consensus blends indicated highs back toaround
90 degrees by early next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1223 PM CDT Thu Sep 15 2016
Mainly a VFR forecast until later tonight and early Friday
morning where lower stratus will be possible but not certain,
mainly near HYS. In the meantime, convective chances for any
terminals remain highly uncertain as the model have high
variability on storm initiation, and coverage. Some models, not
all , initiate convection by late afternoon across east central
Colorado, with more areal coverage as storms move east into
central Kansas by late evening. By contrast, some models keep the
area convection free as they drive the initial storms farther
north into north central Kansas.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 61 81 58 79 / 40 30 30 20
GCK 58 76 55 78 / 30 20 20 20
EHA 58 77 56 78 / 20 20 30 30
LBL 61 80 58 80 / 20 30 30 30
HYS 60 77 55 78 / 50 20 20 10
P28 66 82 63 81 / 20 50 50 30
&&
.DDC Watches/Warnings/Advisories...NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Russell
Area Forecast Discussion
National Weather Service Quad Cities IA IL
320 PM CDT THU SEP 15 2016
.SYNOPSIS...
Issued at 320 PM CDT Thu Sep 15 2016
Increasingly warm and humid air moved into the area through early
afternoon. Temperatures ranged from the upper 70s to lower 80s
under a partly sunny sky. The bulk of the shower and thunderstorm
activity was confined to northwest Iowa into southern Minnesota.
&&
.SHORT TERM...(This Evening through Friday)
ISSUED AT 320 PM CDT Thu Sep 15 2016
Main forecast issues in the short term period
In the near term, isolated showers continue to pop up across the
southern counties. Given the weak layer shear and more favorable
forcing to the west, any storms that do develop should have a hard
time sustaining themselves. The western fringe of the forecast
area would be most favored for additional isolated development
before 00Z, but the bulk of the rain is expected to hold off until
late evening and overnight. Morning runs of the HRRR continue to
verify reasonably well, albeit a bit slow, and were generally
followed for pops through tonight. SPC has pushed the marginal
risk area to the west of the forecast area, with unfavorable
timing for much in the way of a severe threat. The main issue will
continue to be locally heavy rain, with a well above normal
precipitable water feed over 1.5 inches poised to stream into the
forecast area tonight.
On Friday, the most favorable moisture will shift along and east
of the Mississippi River, and additional localized heavy rain is
more likely in the south. Again, no severe storms are expected.
Abundant cloud cover will limit insolation and should keep
afternoon highs down in the mid to upper 70s.
.LONG TERM...(Friday Night through Thursday)
ISSUED AT 320 PM CDT Thu Sep 15 2016
Thunderstorm chances continue for much of Friday night into early
Saturday morning along and ahead of the cold front pushing through
the region. Highest pops and greatest thunderstorm chances are kept
in the evening period, which then wane overnight through Saturday
morning with less favorable diurnal timing, weak shear and limited
forcing. Will keep at least low pops for showers going through
Saturday morning across the southeast based on the timing of the
attendant upper level shortwave trough axis. Breezy west to NW
winds and clearing skies will then follow for Saturday afternoon
with incoming lower dewpoints and highs limited to the mid and
upper 70s. The surface ridge that follows Saturday night will
provide mostly clear skies, light winds and min temperatures in
the 50s, if not around 50 across the cooler northern valleys.
Sunday through Thursday will be marked by a warming trend that will
see temperatures back into the lower 80s by midweek as the upper
level flow becomes zonal and then SW with the passage of a broad
upper ridge to the south. There are significant model difference
with the track of a passing surface low late Monday into early
Tuesday leading to low chances for showers and thunderstorms, which
may need to be increased if the more southerly trending ECMWF and
Canadian solutions continue. Beyond, chances for thunderstorms
remain in the forecast for Wed into Wed night, where the latest GFS
and ECMWF were beginning to suggest a more northerly depiction of a
slow moving front. If this trend continues, then the pops for
these periods may be overdone. Thursday into Saturday looks like
an active period with continued above normal temperatures and
thunderstorm chances with moisture flowing into the region under
an active west to sw flow aloft.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
ISSUED AT 1240 PM CDT Thu Sep 15 2016
Expect mainly low VFR ceilings through this evening. Any isolated
showers through early evening to not warrant a mention in TAFS at
this time. More widespread storms expected to develop between 04z
and 08z tonight with periods of mainly MVFR ceilings and
visibilities, briefly IFR in heavier rain. Have framed a 5 hour
window of most likely rain at each site, extending into Friday
morning at KMLI and KBRL.
&&
.HYDROLOGY...
Issued at 320 PM CDT Thu Sep 15 2016
High river levels, due to recent heavy rains that fell over portions
of east central and especially north central and northeast Iowa,
continued to affect eastern Iowa tributaries. The greatest impact is
along portions of the Cedar and Wapsipinicon rivers.
Along the Wapsipinicon: Routed flow and the contribution from
forecast QPF over the basin the next couple days is currently
forecast to lead to minor flooding at Dewitt beginning late
Sunday. Confidence in this occurring remains low, due to both
uncertainty in the routed flow and the variability of rainfall
coverage and intensity in the current convective environment.
Thus, will continue to hold off on any watches and warnings for
this site.
On the Cedar River near Conesville: An approaching upstream crest is
forecast to pass the site just below flood stage, although there is
a still a potential that it could still push the river into minor
flooding Friday afternoon, which will be watched closely.
&&
.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...RP Kinney
SHORT TERM...RP Kinney
LONG TERM...Sheets
AVIATION...RP Kinney
HYDROLOGY...Sheets
Forecast discussion for routine afternoon forecast issuance
.SHORT TERM...Tonight and Friday
Issued at 354 PM CDT Thu Sep 15 2016
Partly sunny skies with temperatures in the upper 60s to middle
70s prevailed across the region at mid afternoon. The fair weather
cumulus clouds will dissipate around sunset. However, high clouds
will be on the increase during the evening and overnight. At this
time, the latest HRRR model now suggesting precipitation will not
arrive until after midnight. Have small chances of showers late
this evening across the west, with showers likely with a slight
chance of thunderstorms after midnight. Northeast and east-central
Wisconsin should remain dry through the night due to an abundant
amount of dry air in this region.
The rain will make a slow progress eastward into north-central and
central Wisconsin late tonight and should work into northeast
Wisconsin Friday morning. Again, dry air may slow its arrival and
may delay it to mid or late morning. The best chances for rain
will be Friday afternoon and evening as upper level system moves
across the region. The risk for severe weather appears to be very
low due to cloud cover and ongoing rain. If stronger storms were
to be found, they would be across northeast and east-central
Wisconsin where this region will have a chance to warm up before
the rain arrives.
Due to expected rain and low clouds, lowered high temperatures
on Friday across portions of north-central Wisconsin. Across
northeast and east-central Wisconsin, high temperatures will be
around late morning into mid afternoon before the rain arrives.
.LONG TERM...Friday Night Through Thursday
Issued at 354 PM CDT Thu Sep 15 2016
NWP models continue to be fairly consistent in clearing out
showers and thunderstorms from west to east Friday night as a cold
front departs the region to the east. Despite the passage of this
surface feature, the mid level trough will not track through the
area until Saturday, bringing a continued chance for showers to
the region during the first part of the weekend. The best chances
will be across north central Wisconsin given better moisture and
proximity to the mid level trough, however the latest model runs
indicate chances will extend south into central Wisconsin during
the afternoon hours given a bit better moisture than was
previously forecast.
A ridge of high pressure is forecast to build in across the
western Great Lakes on Sunday, bringing drier weather to the
region. However the latest model runs do generate some showers
near the Michigan border with lingering steep low level lapse
rates and meager moisture. Despite this model trend there does not
appear to be much in the way of forcing and as was mentioned
moisture is meager, therefore will keep the forecast dry for the
second half of the weekend with an eye on model trends.
In the early part of next week another low pressure system will
track through the western Great Lakes, bringing a renewed chance
for showers and thunderstorms Monday and Monday night. Moisture
with this system will be fairly meager, therefore will maintain
chancy pops for this period.
A stronger low pressure system with more moisture is set to impact
the western Great Lakes during the middle to late part of the
week. Despite continued model discrepancies, there appears to be
some convergence late in the forecast with the ECMWF and GFS
bringing precipitation to the area Wednesday and next Thursday.
Therefore confidence is a bit higher this run with respect to pops
which is reflected in the pop grids.
&&
.AVIATION...for 18Z TAF Issuance
Issued at 1119 AM CDT Thu Sep 15 2016
Fair weather cumulus clouds between 2500 and 4000 feet expected
across much of the area this afternoon. The fair weather cumulus
clouds will dissipate around sunset. Meanwhile, a cold front will
approach Wisconsin from the west later tonight. The showers should
arrive across portions of central and north-central Wisconsin
after midnight. Look for areas of fog to form. Ceilings will drop
into the ifr/mvfr category late tonight across portions of central
and north-central Wisconsin and continue through much of Friday
morning. There is some uncertainties on Friday morning on how far
east the rain will get into northeast Wisconsin as very dry air
should remain in place. The gfs model moves to the rain to near
Green Bay and Appleton and then dries it up with main rain coming
during the afternoon and evening. Will depict this scenario in
the 18z tafs with more rain and low clouds in the western taf
sites (KRHI/KAUW/KCWA) and higher ceilings and less rain in
the eastern taf sites (KATW/KMTW/KGRB). The rain should end
late Friday night or Saturday morning with improving ceilings
expected on Saturday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....Eckberg
LONG TERM......Kurimski
AVIATION.......Eckberg
Area Forecast Discussion
National Weather Service SAN ANGELO TX
337 PM CDT THU SEP 15 2016
.SHORT TERM...
(Tonight and Friday)
Latest HRRR continues to show embedded disturbances in the flow
aloft tracking eastward primarily across the northern half of the
forecast area into this evening. Totals approaching 3 inches have
already fallen this afternoon over the eastern Big Country. The
northern half of the forecast area will remain the primary target
for additional rainfall through tomorrow. The main weather impact
will continue to be localized flooding.
Morning lows tomorrow will be a few degrees warmer than this
morning with temperatures mostly in the lower 70s. Afternoon highs
tomorrow should also be a few degrees warmer than today with
temperatures in the lower 90s expected.
15
.LONG TERM...
(Friday night through next Thursday)
A summer-like pattern will control the weather in west central
Texas in the long term. Upper level ridging is in place from
southeastern Texas east across the Gulf of Mexico region.
Although there are weak disturbances embedded within this ridge,
these are not expected to affect west central Texas over the next
week.
This ridging puts our area right on the eastern edge of stronger
southwest flow. This flow, combined with abundant low level
moisture, and weak cold fronts and/or leftover boundaries from
previous convection will continue to result in a chance for
showers and thunderstorms for our area from Friday night into
Saturday evening with diminishing chances into early next week.
The best chances at this time appear to be late Friday night into
Saturday morning, depending on the timing of a disturbance moving
through the area Friday night, along with the southern reach of a
cold front expected to move into the Texas Panhandle region.
Following this, upper level ridging becomes centered more over
Texas from Sunday through the middle of next week. This will lower
our rain chances for next week, and result in warmer than normal
temperatures across the area.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 70 89 69 89 / 20 30 50 40
San Angelo 70 93 70 91 / 20 10 30 20
Junction 70 92 70 93 / 20 5 20 30
Brownwood 70 91 70 91 / 20 20 40 40
Sweetwater 70 89 69 88 / 30 30 50 30
Ozona 70 90 69 90 / 20 10 20 20
&&
.SJT Watches/Warnings/Advisories...
None.
&&
$$