Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/06/16
Area Forecast Discussion
National Weather Service Denver/Boulder CO
748 PM MDT MON SEP 5 2016
.UPDATE...
Issued at 748 PM MDT Mon Sep 5 2016
Quiet evening as a dry southwest flow aloft prevails over the
state. A cold front will drop south into northeast Colorado after
midnight. Latest HRRR model runs have moved up the frontal passage
time. Right now looks like the front will push through the Denver
area around 09z. This is expected to bring low clouds with areas
of fog possible. Will increase cloud cover and fog coverage due to
the earlier arrival of the cold front.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 415 PM MDT Mon Sep 5 2016
Warm dry air remains over northern Colorado under moderate
southwest flow aloft. Main issue for this forecast is the
interaction between the cold front dropping south into our area on
Tuesday and the moisture off to the east. Both air masses are cool
enough to have no convection yet today and will likely stay that
way, with warmer moist air limited to Kansas.
Easterly surface winds will likely continue over the northern part
of our area and will bring in the shallow moisture that gave fog
to the northeast corner this morning. Models hint at this
approaching Denver around sunrise. We could wind up with a
Denver cyclone-type circulation with the richer moisture coming in
from the north a few hours either side of sunrise. With clear
skies above it, this could result in dense fog again and that may
be most likely on the edge of the cloud bank which could be near
Denver.
The real cold front should come through during the day. This will
also have moist air behind it, though it could produce more mixing
as well. Not sure how all the details will play out as we could
have the stratus erode before the front and be mixed enough to
have sunshine, or both air masses could be cloudy and the real
cold front just reinforces the low level cool layer and maintains
the stratus at the top of it. Better bet of it being a cooler and
cloudy day on the northeast plains and I moved the forecast in
that direction. Less sure about Denver but cooler in the afternoon
looks pretty likely. If there is sun it could be 80 in the early
afternoon and then closer to 70 by late afternoon. Lots of
complications as far as convection goes, but the bottom line is
that the moisture and warmth will be in different places. Slim
chance of getting some return flow of moist and less cool air,
most likely in the southern part of our area by late afternoon, or
a later front timing hitting weakly capped air, but more likely
just too cool on the plains and too dry in the mountains.
The mountain valleys could be approaching red flag criteria for a
few hours Tuesday afternoon, but there should be a little more
humidity than today. Worst conditions will be around Kremmling and
Walden again. Low enough odds for no highlight at this time.
.LONG TERM...(Tuesday night through Monday)
Issued at 415 PM MDT Mon Sep 5 2016
Tuesday night will see any showers that develop over northeast
Colorado moving off to the northeast as drier air at mid-levels
moves into the state. Early on Tuesday evening, any showers that
have developed will have support from a fairly strong early season
jet in place over the region. Surface temperatures in the evening
will be cool, so the showers would be the result of elevated
instability. By midnight the shower activity should be moving out
of the state.
The rest of the week will see dry zonal flow aloft across the
state with dry and warm conditions. High temperatures could be
back in the mid and upper 80s by Thursday. On Friday, an intrusion
of cool air from the north will cut temperatures back into the
upper 70s. Over the weekend, warmer temperatures return. Early
next week looks like a shift in the pattern with a deep trough
developing over the northern Rockies. Will mention a slight chance
of showers on Monday, but questions remain about how much moisture
the approaching trough will initially contain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 748 PM MDT Mon Sep 5 2016
A slow moving boundary has finally moved southeast of KDEN.
Northeast winds behind it are expected to slowly turn to the north
to northwest through 06z. A cold front will push through the
Denver area around 09z. Winds will turn northeasterly behind it.
Low clouds will develop with ceilings of 500 to 2000 feet
expected. There is a chance for fog and ceilings below 500 feet
from 10z to 15z. Ceilings will slowly improve from 16z-20z.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Meier
SHORT TERM...Gimmestad
LONG TERM...Dankers
AVIATION...Meier
Area Forecast Discussion
National Weather Service Billings MT
859 PM MDT MON SEP 5 2016
.UPDATE...
Upper-low lifting northeastward and most of the showers have come
to an end. Still a few showers possible over far eastern Montana
closer to the better forcing. A few weak showers over the
Beartooths/Absarokas could result in a dusting of snow on the
higher peaks through the night. Hi-res models indicate some low
clouds and fog developing mainly from Treasure County east into
Fallon County in the pre-dawn hours. Although given the moist
boundary layer and clearing skies have decided to keep the
majority of central and eastern Montana with patchy fog. Walsh
&&
.SHORT TERM...valid for Tue and Wed...
Water vapor imagery shows upper trof axis still over the northern
Rockies, with stronger shortwave having departed to our northeast
but lingering PV over south central MT. Convective temps are
rather low and we are already seeing scattered showers develop
west of KBIL and tracking east. There is also an area of
thunderstorms in southeast Carter County extending to near Devils
tower that is along region of strong low level frontogenesis. This
stronger activity should push east of our cwa over the next couple
hours as front does likewise. Overall, expect isolated to
scattered showers and a few low-topped t-storms between now and
sunset courtesy of the cyclonic flow aloft and daytime heating,
along with abundant residual boundary layer moisture. Dry
conditions will prevail late tonight.
Main forecast concern in the short term is fog potential late
tonight into Tuesday morning. Looks like a good setup for fog as
sfc ridge settles in producing light winds and clearing skies. Low
temps tonight should fall below current dew pts, by several
degrees in some places, and HRRR has trended consistently towards
fog across parts of the cwa after midnight. SO, with confidence
have added patchy fog from 06-15z. A Billings upslope fog event is
possible.
We will see some theta-e return into southeast MT on Tuesday with
LIs near -2c by late in the day. Could see a shower/t-storm pop by
late afternoon but better chance of this will be thru the night as
next Pacific shortwave moves thru the area. Will keep isolated
pops for our west-central parts Tuesday night but much better
potential for pcpn will be east of sfc trof, i.e. Rosebud County
eastward, with activity extending into Wednesday morning before
energy shifts east.
We will see a gusty W-NW wind with good mixing in post-frontal
regime across the lower elevations on Wednesday. Gusts should
reach 25-35 mph. Drier air will advect into our cwa behind early
Wednesday shortwave, so will keep only isold pops for the high
terrain.
After a chilly night tonight with lows in the upper 30s to mid 40s
(dewpts are too high for a serious risk of a freeze), temps will
turn warmer the next two days with highs back to the upper 60s to
mid 70s across the lower elevations. This will be closer to normal
but still a few degrees on the cool side for early September.
JKL
.LONG TERM...valid for Thu...Fri...Sat...Sun...Mon...
Good agreement in the global models continues through the
extended period. Northwesterly upper level flow will keep
temperatures seasonably cool with a few showers as a weak
disturbance crosses the region Thursday afternoon into Friday.
Not expecting widespread precipitation with this disturbance, but
the better chance will be to the east and northeast of Billings,
and closer to the upper level low passing over northeastern
Montana. Expect a breezy Friday across the forecast area as the
disturbance quickly passes.
Conditions turn drier and warmer over the weekend with
temperatures nearing 80 on Saturday as a ridge of high pressure
moves overhead. By the end of the weekend, models are beginning to
agree on the next cool down. Global models suggest an upper level
low diving south across the forecast area. With good agreement in
this system being a cooler one, would not be surprised to another
chance for high elevation snow, so lowered temps and increased
precip chances for the higher terrain and nearby foothills. Dobbs.
&&
.AVIATION...
Areas of fog is expected to develop overnight producing MVFR/IFR
conditions. Areas of stratus are likely as well, especially E of
KBIL. The stratus will produce IFR to LIFR conditions E of KBIL.
VFR will return to much of the area after 15Z Tuesday. Lower
conditions may linger longer over KMLS. Expect areas of mountain
obscuration through this evening. Arthur/TWH
&&
.PRELIMINARY POINT TEMP/POPS...
Tue Wed Thu Fri Sat Sun Mon
-----------------------------------------------------------
BIL 044/073 052/072 049/073 048/070 048/079 053/074 045/058
10/U 21/N 11/B 11/U 10/U 12/W 33/W
LVM 037/071 043/070 043/070 041/068 042/077 045/073 039/053
21/U 21/N 11/B 21/U 11/U 13/W 33/W
HDN 042/075 048/074 045/075 045/072 043/081 048/076 042/062
11/U 21/B 11/B 11/U 10/U 02/W 22/W
MLS 044/073 052/073 049/074 048/069 047/080 052/076 047/063
20/U 33/T 11/B 23/W 20/U 02/W 22/W
4BQ 044/071 050/073 048/075 048/068 045/079 051/076 045/061
22/T 32/T 11/B 21/N 10/U 01/U 22/W
BHK 043/069 049/070 046/072 046/065 043/076 049/075 044/060
20/B 45/T 12/W 22/W 20/U 01/U 22/W
SHR 041/073 047/073 044/074 044/068 042/079 047/077 042/054
22/T 21/B 11/B 21/B 10/U 12/W 33/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Columbia SC
1046 PM EDT MON SEP 5 2016
.SYNOPSIS...
Fair weather expected to continue through this week, as dry high
pressure dominates. A frontal boundary will move into the region
this weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Upper ridging remains centered across the lower Mississippi River
Valley region, while surface high pressure remains centered north
of the area. Surface ridge axis pushes southward east of the
Appalachians down into northeastern Georgia. The center of the
high will push further southward towards the southeastern states
through tonight. This pattern will continue to push drier air
into the region from the north. No rainfall expected. Under
mostly clear skies and light/calm wind, near to slightly below
normal overnight lows expected in the middle 60s.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Fair weather to continue with a slight warming trend.
Upper/Surface low pressure to move very slowly offshore the NE
coast. Large upper level ridge to our west will slowly move
eastward through mid/late week. As heights slowly build...boundary
layer temperatures and H8 temperatures rise. Can expect a gradual
increase in temperatures through mid week. Airmass to remain
relatively dry as shown by bufkit time section. Expect some
afternoon cu each day with mostly sunny days and mainly clear
night. Temperatures gradually warming to above normal by midweek.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Upper ridge axis over our region through the later part of the
week into early Saturday. Surface high pressure across the area
will begin to move off the coast by Friday/Friday night. Dry
atmosphere to remain in place, with mid level capping and not
expecting any chance for precipitation through the end of the
week. Models indicating upper trough to dig into the E CONUS late
in the forecast period...Saturday/Sunday with appearance of a
frontal boundary or two entering our region. Latest model runs
trending towards the system having a little more moisture to work
with. Accepted latest blend of guidance which provides slight
chance pops late Sat/Sat night...trending up towards chance
Sun/Sunday night and continuing into Monday.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
VFR conditions expected through the 24 hour forecast period.
Surface high pressure will be dominant through the forecast period
with upper level ridging just west of the area. Overnight,
relatively dry air will inhibit fog formation. Model guidance may
be overly pessimistic bringing in mvfr visibilities early Tuesday
morning. The HRRR has been consistent with VFR visibilities
throughout the night.
Tuesday, the general wind field will be around 5 knots out of the
w/nw but may remain variable at TAF sites throughout the day.
Models suggest slightly higher dewpoints which will allow for a
few scattered afternoon cumulus clouds but no precipitation is
expected with synoptic subsidence in place.
EXTENDED AVIATION OUTLOOK...No significant impacts expected
through Saturday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Des Moines IA
628 PM CDT Mon Sep 5 2016
.SHORT TERM.../Tonight/
Issued at 344 PM CDT Mon Sep 5 2016
The primary concern will be convective trends later tonight. Much
of the precipitation has exited the state with the warm sector
surging northward and the best 0-2km moisture convergence now from
SD across southern MN. Heat indices are now into the mid 90s
central and south. The front is currently on the Siouxland
doorstep and impacts for IA weather will depend on whether it will
develop more surface based soon, or wait for more of an elevated
potential later this evening. Conditions are quite favorable for
supercell development just to our west, and the Bunkers motion
would suggest a more easterly motion if that were to occur. This
would eventually push the outflow and convergence farther south
into IA to be realized by the low level jet and associated
convergence. However examination of visible satellite imagery
currently shows little vertical development along the front.
The more likely scenario, and that supported by most models, is
that strong moisture transport along the 305K isent surface will
produce convection from the Siouxland area across southern MN fed
by 35- 45kts of inflow. The RAP mean wind suggests motion parallel
to the front with Corfidi vectors either neutral or weak from the
same direction. This supports a heavy rain potential just across
our border with precipitable water, specific humidity and
integrated water vapor transport all very near climatological
maxes. Have added heavy rain wording to the forecast north, but
held off on a headline for the moment due to this thinking and
high resolution models highlighting MN rather than IA as well.
.LONG TERM.../Tuesday through Monday/
Issued at 344 PM CDT Mon Sep 5 2016
Active weather pattern sets up this week with periodic severe
weather and heavy rain potential Tuesday into Wednesday. Utilized
a blend of the ECMWF/NAM Tuesday into Wednesday, and then a
ECMWF/GFS blend through the remainder of the forecast period.
Tuesday into Wednesday...Models continue to shift convection
further north during the day Tuesday with the frontal boundary
looking to drape across far northern Iowa into southern Minnesota.
The latest ESRL HRRR, NSSL WRF, and SPC WRF have all shifted the
convection further north and delayed the timing until late
Tuesday afternoon. There maybe some elevated convection that
develops during the afternoon within the WAA regime and theta-E
advection north of Highway 30. However, a fairly strong cap
remains in place and the stronger forcing looks to transition
further north into Minnesota through the day Tuesday. Shaved off
pops across the southern portions of the forecast area during much
of the day Tuesday. With the drier forecast, leaned toward
increasing winds and temperatures for Tuesday with the good mixing
and strong surface pressure gradient. The stronger winds are
likely to occur over the southern two-thirds of the CWA.
Strong moisture transport continues across the state Tuesday night
into Wednesday. Deep moisture convergence will be along or just
north of the Iowa/Minnesota border by 00z Wednesday and gradually
transitions south-southeast through 12z Wednesday as the front is
slow to move. By around 12z Wednesday, the front looks to remain
oriented from around MCW to ALO southwest to DNS to CRL area into
east-central Nebraska. A strong atmospheric river continues to
pump moisture into this area with warm layer clouds depths
remaining persistent around 4000 meters between 00-12z Wednesday
and even through much of the day Wednesday. Another shortwave
tracks across the state Wednesday providing additional
thunderstorm chances. Certainly a long duration moderate to heavy
rain threat and have introduced mention of heavy rain across
northern Iowa during this time. With the PWATs ranging from
1.5-2.0 inches Tuesday into Wednesday, slow storm motion and
possible training of thunderstorms, the potential exists for flash
flooding Tuesday night into Wednesday. River flooding is also
possible over portions of northern Iowa, but had low confidence to
issue any hydrologic related headline due to the uncertainty of
frontal boundary location as well as the delayed timing of the
convection. May need to consider at least a flash flood watch over
the far northern portions of the CWA for late Tuesday night into
Wednesday. Some of the contingency river forecasts (max QPF vs
min QPF) for the Cedar River Basin reach just over minor flood
stage (if at all) and not until late in the work week into the
weekend for any potential impacts. The only concerned location
would be Cedar Falls (CEDI4) if the max QPF forecast comes true in
this basin.
As far as the severe weather potential, agree with the Slight Risk
shifting further north where the boundary is located on
Tuesday/Tuesday night. 0-6km bulk shear ranges near 35-40 knots over
far northern Iowa Tuesday evening with decent MLCAPE values present.
Initial storm mode looks to be supercells but will likely quickly
transition into heavy rain producers. Cannot rule out the threat for
wind late tomorrow night into Wednesday morning over far northern
Iowa with the amount DCAPE present (500-1000J/kg). MCS maintenance
probability over the north ranges around 40-50% overnight into
Wednesday morning.
Thursday into Friday...Surface high pressure builds into the state
Thursday but is quickly removed a fairly decent surface low pressure
and mid-level shortwave moves northward into the state by Friday
morning. A strong trough and cold front move south late Friday night
into Saturday, with Saturday morning looking to be somewhat windy
behind the front. GFS is slightly more potent than the ECMWF, but
both are in agreement with the timing of the trough Friday night.
&&
.AVIATION.../For the 00Z TAFS through 00Z Tuesday evening/
Issued at 628 PM CDT Mon Sep 5 2016
Little impacts through 06z with northern sites KFOD/KMCW possibly
seeing convection between 06-14z into KALO closer to 12z as
late evening Minnesota/South Dakota storms move over southern MN
by 12z Tuesday. Main concern for most of the area aft 18z Tuesday
as more storms begin to develop along/north of US20 moving south
as front approaches. Southwest winds once again likely to be 12 to
25kts aft 19z most areas. Southern sites KDSM/KOTM will more
likely be affected with thunderstorms aft 00z Wed. Will monitor
overnight convection for timing north and update if needed timing
for southern sites at 06z. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Small
LONG TERM...Podrazik
AVIATION...rev
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
803 PM CDT MON SEP 5 2016
.UPDATE...
Most of the convection has moved off to the north. Only current
activity is approaching Dimmit County. Other storms south of our
CWA our dissipating rapidly. Have lowered POPs over most of the
CWA for the rest of tonight. Otherwise, have only adjusted hourly
grids to account for observational trends.
&&
.PREV DISCUSSION... /ISSUED 646 PM CDT MON SEP 5 2016/
UPDATE...
00Z Aviation Update Below.
AVIATION...
VFR conditions will prevail through the evening hours. MVFR to IFR
ceilings will develop again 06Z-08Z along the I-35 corridor and
west through the Hill Country and along the Rio Grande. Some LIFR
ceilings developed early this morning, and there again exists the
possibility of this from SAT-AUS between 10Z-14Z. Some patchy fog
may also produce IFR to MVFR ceilings near and east if the I-35
corridor during this time. MVFR ceilings then VFR conditions
re-develop 15Z-18Z.
SHRAs and TSTMs have exited South-Central Texas. Hi res ARW/NMM
and to lesser extent latest runs of the TT WRF and HRRR suggest
some possible re-development of isolated SHRAs during the day on
Tuesday up the I-37 and I-35 corridors.
PREV DISCUSSION... /ISSUED 230 PM CDT MON SEP 5 2016/
SHORT TERM (Tonight through Tuesday)...
Main highlight through tomorrow will be the daily isolated to
scattered afternoon showers and thunderstorms bringing brief
heavy downpours.
An active sea-breeze with an upper-level low over the Texas coast
coincident with PWATS near 1.7" is aiding shower and thunderstorm
development this afternoon along and east of US 281. Locally brief
heavy downpours will occur but storm motions are quick enough from
south to north not to worry about any flooding concerns. A
majority of the upper-level energy looks to pass into NE Texas
through mid to late afternoon and this may help slight subsidence
on the backside and limit coverage southward behind the ongoing
activity. Most of the ongoing activity will diminish through the
7-9pm range.
Low clouds and fog are expected to develop overnight with some
visibilities dropping to 3 miles in coastal plain areas. A few
showers my develop early where residual upper-level energy resides
across over the I-37/35 corridor. This residual energy combined
with weak instability Tuesday afternoon should foster some
additional shower/storm activity. Overall however, coverage should
be less than today.
LONG TERM (Wednesday through Monday)...
Drier and slightly warmer conditions expected mid- to late-week
as a ridge of high pressure develops over the region. A front will
approach the region next weekend but looks to stall just north of
South-Central Texas.
Higher geo-potential heights are centered over the Mid-Tennessee
Valley currently and the center, plus its influence, is expected
to shift southwest towards east Texas through mid-week. This will
help suppress afternoon convection with only isolated sea-breeze
activity making into the coastal plains. Have only placed a 20-30%
chance of rain in those locations through the week. High
temperatures will climb back into the low and mid 90s for most of
the region with still some upper 80s holding on in the Hill
Country. These readings will be near normal for this time of year
but lows will remain above normal as low to mid 70s remain given
ample SE moist flow still in place. With the ridge in place, the
moisture from a Pacific tropical system will be pushed farther
north and west away from south-central Texas and not pose a heavy
rain risk.
Differences remain in the GFS vs. EC long range output on the
potency of a trough axis across the central CONUS. GFS remains
quite sharp and strong while the EC is more muted. Regardless,
both models attempt to bring a front into Texas but it looks to
stall north of the region. Have continued the trend of low rain
chances (20-25%) for the northern areas for now given the lack of
southward frontal momentum next weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 76 91 76 91 76 / 10 30 20 10 10
Austin Bergstrom Intl Airport 75 91 75 91 75 / 10 30 20 20 10
New Braunfels Muni Airport 75 91 76 92 74 / 10 30 20 20 10
Burnet Muni Airport 74 89 74 90 74 / 10 20 10 10 10
Del Rio Intl Airport 76 92 76 95 75 / 10 20 10 10 -
Georgetown Muni Airport 75 90 76 90 75 / 10 20 10 10 10
Hondo Muni Airport 76 92 76 93 73 / 10 20 10 10 -
San Marcos Muni Airport 75 91 75 91 74 / 10 30 20 20 10
La Grange - Fayette Regional 76 92 76 92 76 / 10 30 20 20 10
San Antonio Intl Airport 77 91 77 92 76 / 10 20 10 10 10
Stinson Muni Airport 77 93 77 94 76 / 10 30 20 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Runyen
Synoptic/Grids...05
Public Service/Data Collection...Williams
Area Forecast Discussion
National Weather Service Grand Forks ND
957 PM CDT MON SEP 5 2016
.UPDATE...
Issued at 954 PM CDT Mon Sep 5 2016
Convection continues to expand from just south east of Moorhead
over to Walker MN, with storms remaining well below severe limits.
Latest HRRR guidance does keep this activity short lived and
weaken it after midnight...so will increase and adjust POPs in the
southern Valley through 09Z. A band of showers is also moving
along the Canadian border and have expanded scattered eastward
into NW Minnesota for the next several hours.
UPDATE Issued at 644 PM CDT Mon Sep 5 2016
A few non severe storms have popped up over the far southeast, as
expected...and not changes with scattered storms indicated in
current forecast. Temperatures look on track...made slight changes
to sky for aviation grids. No other changes expected.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 305 PM CDT Mon Sep 5 2016
Less weather impacts across the region through the short term.
Surface boundary hung up on the far eastern edge of the forecast
area this afternoon. Instability not impressive however around
500j/kg mu cape so will hold on to some pops this area. Farther
west sct shra in central ND associated with wave lifting through
western trough might clip parts of the DVL basin so kept pops
there. The remainder of the forecast area should remain between
above mentioned features and have pulled pops for the night. Low
temperatures tonight should be close to seasonal averages.
Surface high pressure builds into the forecast area tomorrow for a
quiet day. Relatively cool column in place so max temperatures
will range a bit blo average dependent on degree of cloud cover.
Will hold on to a narrow ribbon of pops across the far SE FA which
may be on the northern fringe of rain band to our south and east.
.LONG TERM...(Tuesday night through Monday)
Issued at 305 PM CDT Mon Sep 5 2016
Active pattern for the first week of September continues as Tuesday
night into Wednesday night will see another short wave move across
the area in the SW flow aloft. Lighter rainfall amounts are expected
with this system as Pwats are less and the system is more
progressive, lessening the potential duration and intensity. Most
likely scenario is that amounts will range from a tenth to a half an
inch.
Thursday into the next weekend...Another round of rain chances
enters the area thursday night and will linger through Friday
clearing out Friday night as 500mb trough digs into the northern
plains. Seasonal temperatures are expected with highs around 70 and
lows in the low 50 warming some on Sunday into the mid 70s as 500mb
ridging occurs ahead of another wave on Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 644 PM CDT Mon Sep 5 2016
MVFR conditions expected during the overnight hours and slow
recovery to VFR during the late morning and afternoon tomorrow.
Light winds through the 24-hour period.
&&
.FGF Watches/Warnings/Advisories...
ND...None.
MN...None.
&&
$$
UPDATE...Speicher
SHORT TERM...Voelker
LONG TERM...JK
AVIATION...Speicher
Area Forecast Discussion...UPDATED
National Weather Service Miami FL
953 PM EDT MON SEP 5 2016
.UPDATE 2...
Quick update to the forecast for tonight. Most of the
thunderstorms have ended late this evening over South Florida,
except for a few over the eastern areas. These thunderstorms will
continue to slowly dissipate through rest of the late evening
hours, but there could still be a few storms that develop in the
Atlantic waters that work into the east coast metro areas.
Therefore, the thunder threat will be lower to isolated coverage
for the eastern areas of South Florida, while the western areas of
South Florida will see mostly dry conditions after midnight.
&&
UPDATE 2...BNB/54
.PREV DISCUSSION... /issued 809 PM EDT MON SEP 5 2016/
UPDATE...
Scattered convection continues to slide southward over the CWA
this evening. Latest short range guidance decreases the coverage
and intensity of the storms at the night progresses. However, in
the short term, updated the grids to raise pops along Collier
County and the Gulf Coast waters. Otherwise, forecast looks on
track. The elongated moisture front sitting over the region will
persist through tomorrow and another active day of convection is
expected.
&&
PREV DISCUSSION... /issued 746 PM EDT MON SEP 5 2016/
AVIATION...
The winds will remain light and variable tonight over all of the
taf sites before increasing from the northeast to around 10 knots
on Tuesday. There should be some showers around tonight over the
east coast taf sites. Therefore, VCSH will be in the east coast
taf sites for tonight. For KAPF taf site, the VCSH will continue
until 02Z, then dry for rest of tonight. For Friday, VCTS will
start after 15Z for all of taf sites. The ceiling and vis will
also remain in VFR conditions through Tuesday for all of the taf
sites.
&&
AVIATION...54/BNB
PREV DISCUSSION... /issued 439 PM EDT MON SEP 5 2016/
SYNOPSIS...
Numerous showers and thunderstorms will continue into
early evening over most land areas. During the evening, showers will
slowly diminish with the loss of daytime heating. Through Friday,
as high pressure builds over the Atlantic, deep southeast flow
will favor an enhancement of shower/thunderstorm activity across
the interior and Gulf regions of South Florida. During the nights,
activity will favor the east coast. Expect near normal temperatures
for this time of year.
DISCUSSION...
Water vapor imagery continues to show a mid to upper level
moisture boundary draped east to west across South Florida.
Analyzing the 12Z morning sounding, there were multiple indicators
of an active day with respect to convection. First, CAPE values
were around 3500 J/KG, a sufficient amount for strong updrafts. No
appreciable temperature inversion (cap) could be seen, which had
favored early initiation. A PW value of 2.14 represented a very
moist atmosphere. This, in combination with weak winds in the low
to mid levels, has led to increase risk of flooding today in low
lying and poorly drained areas. The HRRR and Hi-Res WRF model keep
convection ongoing through at least early evening. Have left
likely pops in the grids over all land areas to account for this.
The water spout potential will remain elevated along the coastal
waters due to light winds in the lower levels. Tonight, after the
loss of diurnal heating, shower and storm activity should diminish
with highest chances remaining along the east coast. On Tuesday,
the 12Z GFS keeps the aforementioned mid and upper level moisture
front over the CWA with the highest PW near the very southern tip
of Florida. Thus, chance to likely pops have been added to this
region Tuesday afternoon. The main impacts from these storms will
again be heavy rain, brief gusty winds, and frequent lightning.
Wednesday through Thursday, high pressure building over the Atlantic
will bring a return to the more typical summerlike pattern to South
Florida with east flow prevailing. Expect highest chances of
afternoon, sea breeze driven showers and storms over the interior
and Gulf Coast. During the nights, activity may shift towards the
east coast. From Friday into the weekend, long range models
advect higher moisture up from the tropics and increase storm
activity.
Beaches: From this evening through Wednesday, models project a 3-4
foot 11-12 second swell, generated by Hermine, to drop southward
down our Atlantic coastal waters. This scenario would create
elevated surf along the Atlantic beaches and an enhanced rip current
risk. These conditions may warrant marine and rip current products
to be issued later this afternoon.
AVIATION...
Weak boundary sliding south into region helping to
generate SHRA/TSRA over ATLC that are occasionally brushing east
coast. Coverage increases across rest of region after 14Z becoming
sct-nmrs, but confidence in timing is low so will keep VCTS
rather than TEMPO groups. TEMPO MVFR conditions with most
activity, occasional IFR with heavier showers. Prevailing ENE flow
through the day.
MARINE...
High pressure ridge continues to build across the
Atlantic through late in the week with chance of showers and
thunderstorms throughout the period. A 11-12 second swell,
generated, by Hermine, will push south through the Atlantic
coastal waters late today through early Wednesday building seas
close to exercise caution to advisory along the Atlantic waters
late tonight into Tuesday. Seas could peak around 3-5 feet east of
Miami- Dade/Collier counties and 5-7 feet in the coastal waters
east of Palm County. Conditions will begin to improve by late
Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 77 88 76 88 / 30 40 30 40
Fort Lauderdale 77 89 77 88 / 30 50 40 40
Miami 77 89 77 90 / 30 60 40 40
Naples 75 90 73 89 / 20 50 20 50
&&
.MFL Watches/Warnings/Advisories...
FL...High Rip Current Risk through Wednesday evening for FLZ168-172-
173.
AM...Small Craft Advisory for hazardous seas until 8 AM EDT Wednesday
for AMZ650-670.
GM...None.
&&
$$
SHORT TERM...54/BNB
LONG TERM....27/JT
Area Forecast Discussion
National Weather Service Omaha/Valley NE
800 PM CDT MON SEP 5 2016
.UPDATE...
Issued at 742 PM CDT MON SEP 5 2016
Severe thunderstorm watch has been issued until 3 AM for seven
counties in northeast Nebraska. While some broken cumulus has
developed along front in northeast Nebraska from Antelope into
Knox counties, vigorous convection has been limited by weak low
level convergence and rather low mid level lapse rates. However
storms currently in southwest Nebraska and perhaps a few
developing in central Nebraska are expected to ride frontal zone
northeast into our area later this evening and past midnight.
Latest runs of HRRR have latched on to this scenario somewhat. Any
storms that make it into northeast Nebraska will have plenty of
instability to work with as 00Z Omaha sounding suggested nearly
3000 j/kg of CAPE was working into that area, along with effective
bulk shear near 40kt. Freezing levels are awfully high, around
15000ft off of Omaha sounding, so large hail will be confined to
more organized storms. Stabilizing boundary layer will also
inhibit strong winds initially, though fairly high Downdraft CAPE
values point to microburst potential. Will continue to monitor
situation.
&&
.SHORT TERM...(tonight through Thursday)
Issued at 337 PM CDT MON SEP 5 2016
Latest water vapor imagery in combination with RAP analysis shows
a mid level trough axis extending from southwestern Canada into
the Great Basin with a lead shortwave drifting northeast across
Wyoming and into into the western Dakotas. 12z upper air analysis
showed an 850mb thermal ridge extending from the southwestern
CONUS all the way into southern MN with dewpoints around +16 to 17C
aided by a 50kt southwesterly low level jet. PW`s remain high with
the 12Z observed sounding indicating 1.82". At the surface this
afternoon...a cold front extended northeast from lee side low
pressure over western Colorado across central Nebraska and into
northeast South Dakota. Latest visible satellite shows a
shrinking stratus deck over western and north central Nebraska
behind the frontal boundary with a congested CU field over
northeast Nebraska.
Focus for thunderstorms late this afternoon/evening will be along
the surface front with latest CAMs indicating development as
early as 20-22Z across northeast Nebraska. RAP analysis shows cap
is quickly diminishing in this area with MUCAPE values around
2500-3000 J/KG. This activity should persist for a few hours
before moving off to the northeast with the main activity
forecast to develop across northwestern Kansas and move along the
boundary overnight. CAMS also show potential MCS development
across north Central Nebraska overnight and sliding along the
Nebraska/South Dakota border. Thus, much of the CWA should remain
dry overnight except the north.
The front begins to slowly drift southeast Tuesday with increasing
potential for heavy rain along and behind the boundary.
Possibility for a few supercells does exist across a portion of
the northern CWA Tuesday afternoon where a slight risk has been
outlooked from SPC.
Front finally slides south Wednesday when mid level shortwave
kicks through. Again...the potential for heavy rain exists with
strong to severe thunderstorms. Wednesday night into Thursday
looks dry as the frontal boundary pushes south of the forecast
area.
.LONG TERM...(Thursday night through Monday)
Issued at 237 PM CDT MON SEP 5 2016
By Thursday night, the front begins to lift north as another mid
level shortwave ejects into the Central Plains. A stronger
shortwave trough will move through the Northern Plains Friday
pushing a much stronger cold front through the CWA leaving the
area dry for next weekend.
&&
.AVIATION...(00Z TAFS for KOFK...KLNK and KOMA.)
Issued at 652 PM CDT MON SEP 5 2016
Main concern is possible strong/svr TSRA later tonight. Latest sfc
obs reveal a boundary extending from srn MN to nw KS with convective
activity already moving into s-cntrl Neb. Given the models move
the boundary little overnight along with TSRA trajectory trends
the last couple hours...it appears the main threat for TSRA will
be at KOFK shortly after midnight. Believe potential for svr
storms by that time though will be minimal. Otherwise VFR cond
will prevail thru the fcst pd.
&&
.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&
$$
UPDATE...Dergan
SHORT TERM...Kern
LONG TERM...Kern
AVIATION...DEE
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php
Area Forecast Discussion
National Weather Service Albuquerque NM
328 AM MDT TUE SEP 6 2016
.SYNOPSIS...
Widespread storms are expected today and tonight mainly east of
the Continental Divide. Abundant amounts of moisture will lead to
heavy rain producing storms and potentially flash flooding. A
Flash Flood Watch is in effect for much of eastern New Mexico this
afternoon and overnight. In addition to the flooding concerns,
some storms may become briefly severe, producing hail and high
winds. Remnants of Hurricane Newton will move into western New
Mexico Wednesday and Wednesday night. More heavy rain is
possible, though now favoring the southwest and west central
mountains.
&&
.DISCUSSION...
Vort max associated with the thunderstorm cluster in Mexico 24-hours
ago has, as expected, shifted northward and produced yet another
cluster of thunderstorms in Mexico ahead of Hurricane Newton. There
is some concern this morning that the disturbance/vort max that will
be associated with the latest thunderstorm cluster will be a little
further west than what models indicate as it shifts over NM today.
This could mean greater storm coverage between the ContDvd and the
central mtn chain than forecast. Nonetheless, still believe the
greatest risk for heavy rain and flash flooding is along and east of
the central mtn chain this aftn/eve. Thunderstorms have persisted
much of the night across north central and northeast NM and some
areas have received quite a bit of rain. Therefore, have opted to
expand the Flash Flood Watch northward to the Colorado border to
cover these areas that now have saturated soils. Additionally, the
NAM, HRRR and local WRF are also showing signals of heavy rain
producing storms across the northeast. Though storm motion will be
pretty fast, training storms will be possible, similar to last night.
Secondary to the flash flooding concerns, models also show quite a
bit of instability and shear. Thus a few strong to severe storms are
possible again today as well.
As the vort max shifts across eastern NM, models have been
consistent at developing a cluster or broken line of storms across
the east central and southeast plains this evening. This is where
confidence is highest that heavy rainfall may produce problems as
copious amounts of moisture will be in place with ample lift.
Newton`s track appears to be a bit further east this morning and
therefore its remnants cross NM a bit sooner than originally
expected. By Wed afternoon, the center of Newton should be over SE
AZ, and as it shifts eastward into NM Wed night, it should open into
a trough. Heavy rainfall amounts are expected with Newton`s
remnants, mainly across the southwest and west central mountains.
Rainfall will be persistent, lingering pretty much all day Wednesday
and Wed night. Flash flood watches will likely be needed for this
area.
As the system weakens, it will continue to cross NM on Thursday, and
though it will cross slowly thru Thursday night, it no longer looks
like it will stall over the state. Additionally, it appears much
drier air will move in behind the system. Thus, after Thursday
morning, rain chances really taper off for the latter part of
Thursday and early Friday.
A back door front is still slated to come down the plains, though it
looks to be a bit slower, arriving late Friday afternoon across the
NE and quickly pushing south and west Friday night. Storms are still
possible along and behind the front across the east Friday evening,
though models are a bit less bullish this morning - likely owing to
the drier air aloft behind Newton`s remnants. Still looking for a
healthy east canyon wind Saturday morning in the Rio Grande Valley
replenishing low level moisture across the west. Yet another front
may arrive on Tuesday. Might start to feel like Fall.
34
&&
.FIRE WEATHER...
Moisture surges today and later Wednesday will bring widespread
wetting rains to northern and central New Mexico into Thursday.
There will be areas of heavy rain and localized flash flooding.
A ridge of high pressure to our east and a trough of low pressure to
our west are allowing increased moisture to advect north and
northeast into NM. An upper level disturbance over northern Mexico
will move northeast across the state today, significantly enhancing
shower and thunderstorm coverage through tonight. There will be
heavy rain with the potential for localized flash flooding. Only the
far northwest will be rainfree today with minimum RH values in the
teens. Ventilation will be mostly good to excellent. Highs today
will be cooler than Monday, close to normal.
The drying trend across the north for Wednesday is not as pronounced
now as the past few days have shown. This looks to be the result of
the faster moving remnants of Hurricane Newton, which brings a
healthy dose of moisture into our southwest zones by the end of
Wednesday. Wetting rains will be limited across the northern half of
our zones Wednesday, but will occur across the southern tier, and
rain could be heavy in the West Central Highlands. Vent rates will
take a hit Wednesday with mostly fair to good rates, with an area of
poor ventilation over the West Central Highlands. Highs will
continue to trend down, mostly below normal except for the
northeast.
The bulk of the precipitation from the remains of Newton will cross
NM Wednesday night. The closed low will quickly open up to a trough
of low pressure Thursday with precipitation beginning to diminish.
Ventilation will be fair to good Thursday, but again poor over the
West Central Highlands, and perhaps joined by small portions of the
northeast. Maximum RH will be fair to poor Wednesday night.
Friday will be dry with more sunshine and higher temperatures,
mostly a little above normal. A back door cold front is still
scheduled to arrive across the east Friday night and then spill into
the Rio Grande Valley Saturday. This fresh supply of low level
moisture will bring a return of showers and storms Friday night to
the east and across the south on Saturday.
Moisture will begin to return to the west Sunday, and expand north
and east Monday and especially Tuesday.
CHJ
&&
.AVIATION...
06Z TAF CYCLE
Very active period next 24hrs as a deep tap of tropical moisture
surges north into NM. Storms w/ +RA and gusty outflows continue
to move E/NE across northeast NM late tonight, while a few cells
attempt to push north into south central areas. Expecting low
cigs/vsbys to develop around KLVS where +RA occurred earlier.
Cigs near 015 also possible around KROW as occurred the past few
nights, but confidence not as high for tonight. Tuesday will see
storms develop by 18Z then move north into large clusters with
MVFR and brief IFR excursions from +RA.
Guyer
&&
.PRELIMINARY POINT TEMPS/POPS...
Farmington...................... 88 56 82 53 / 5 5 5 10
Dulce........................... 82 51 78 49 / 20 20 10 10
Cuba............................ 79 53 74 52 / 40 20 10 20
Gallup.......................... 85 49 78 48 / 5 10 20 30
El Morro........................ 79 51 71 50 / 10 20 30 60
Grants.......................... 82 52 75 49 / 20 20 20 60
Quemado......................... 81 54 72 52 / 30 20 60 70
Glenwood........................ 85 60 77 58 / 20 30 70 60
Chama........................... 74 46 72 46 / 30 20 10 10
Los Alamos...................... 76 56 75 52 / 60 40 20 20
Pecos........................... 75 55 75 53 / 70 50 20 20
Cerro/Questa.................... 75 52 74 50 / 50 30 10 5
Red River....................... 67 47 64 45 / 70 30 10 10
Angel Fire...................... 73 47 71 42 / 70 40 10 10
Taos............................ 79 52 76 46 / 40 30 10 5
Mora............................ 73 55 74 53 / 70 40 20 20
Espanola........................ 82 58 80 55 / 50 30 20 10
Santa Fe........................ 77 57 74 54 / 60 40 20 20
Santa Fe Airport................ 81 56 78 54 / 50 40 20 20
Albuquerque Foothills........... 82 61 78 58 / 50 40 20 40
Albuquerque Heights............. 84 62 80 59 / 40 40 20 40
Albuquerque Valley.............. 86 60 83 58 / 40 40 20 40
Albuquerque West Mesa........... 85 63 82 59 / 40 40 20 40
Los Lunas....................... 86 61 82 58 / 40 40 20 50
Rio Rancho...................... 85 62 82 59 / 40 40 20 40
Socorro......................... 84 63 83 62 / 40 50 40 70
Sandia Park/Cedar Crest......... 77 58 75 55 / 70 50 20 40
Tijeras......................... 81 59 77 55 / 60 50 20 40
Moriarty/Estancia............... 78 56 77 53 / 60 40 20 30
Clines Corners.................. 76 55 75 54 / 70 50 30 30
Gran Quivira.................... 76 57 74 56 / 60 50 40 50
Carrizozo....................... 80 60 79 60 / 50 50 40 50
Ruidoso......................... 72 56 72 56 / 80 70 60 50
Capulin......................... 79 57 80 55 / 60 30 10 5
Raton........................... 82 56 82 52 / 60 30 10 5
Springer........................ 82 58 83 53 / 60 30 10 5
Las Vegas....................... 78 54 78 53 / 60 40 20 10
Clayton......................... 85 63 85 61 / 50 40 10 5
Roy............................. 80 60 81 57 / 60 40 20 10
Conchas......................... 86 66 86 62 / 60 50 20 10
Santa Rosa...................... 85 64 85 62 / 60 50 30 20
Tucumcari....................... 89 66 88 64 / 40 60 30 20
Clovis.......................... 83 65 83 63 / 60 70 40 30
Portales........................ 83 66 83 65 / 60 80 40 30
Fort Sumner..................... 84 66 83 64 / 60 60 40 20
Roswell......................... 85 67 84 66 / 60 70 40 30
Picacho......................... 79 62 80 62 / 60 70 50 30
Elk............................. 73 59 75 59 / 70 80 60 40
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from noon MDT today through late tonight for the
following zones... NMZ515-526>540.
&&
$$
34
Area Forecast Discussion
National Weather Service Quad Cities IA IL
327 AM CDT TUE SEP 6 2016
.SYNOPSIS...
Issued at 135 AM CDT Tue Sep 6 2016
Much of the area was clear during the early morning hours, with
some clouds across far northeast Iowa. Showers and thunderstorms
continued well to the northwest, from eastern Nebraska into
northern Wisconsin. Early morning temperatures were mainly in the
low to mid 70s.
&&
.SHORT TERM...(Today and Tonight)
ISSUED AT 135 AM CDT Tue Sep 6 2016
The main forecast issues in the short term period are the heat and
humidity today, and coverage/timing of thunderstorms late this
afternoon and tonight.
In the near term, recent runs of the HRRR hint at some isolated
showers across the north this morning, and there have been some
light echoes developing to the north of the forecast area.
However, with such low probabilities have kept rain out of the
forecast and we can re-evaluate through daybreak.
For today`s highs, have boosted Monday`s temps 2 to 3 degrees most
areas with favorable southwest flow and warmer 850mb temps. That
yields highs in the 87 to 91 degree range. Based on trends upstream
and Monday`s observations, dewpoints in the 71 to 74 range look
reasonable for today, yielding widespread afternoon heat indices
of 95 to 100 degrees. There may be a few locations near or
slightly above the 100 degree advisory criteria for a few hours,
but these higher readings are not expected to be widespread enough
to warrant an advisory. We anticipate handling with a special
weather statement.
Showers and storms could spill into the Highway 20 corridor late
this afternoon, but are more favored later this evening and
overnight, especially across the northwest half of the forecast
area, associated with the nose of a 35 to 40 kt low level jet. The
overall severe weather threat is low, although gusty winds will be
possible with a few storms in the north.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 135 AM CDT Tue Sep 6 2016
Wednesday...Threat for heavy rainfall rates and localized flash
flooding are the main concerns. From a synoptic standpoint, the
atmospheric setup is quite favorable for extremely efficient rain
producing thunderstorms with rainfall rates possibly in excess of
2"/hr. There is also a marginal risk for severe thunderstorms.
Models are forecasting several key ingredients that are typically
associated with Predecessor Rainfall Events:
1) Moist 850-500mb sub-tropical flow from the western Gulf into the
Midwest manifest as an anomalously strong Atmospheric River. Put
into historical context, the NAEFS IVT (WV transport) is forecasting
near record values for September based on a 30-yr model climatology.
2) Additional mid-upper level moisture flux contribution from a
tropical system entering into SE Arizona and NW Mexico, could raise
PWATs near 2.25" -- also near record territory for early September.
The tropical system`s contribution to increased PWATs and mid to
upper level saturation is corroborated by 700-500mb advection of
greater than 90% RH from the Southwest U.S. into the Midwest. Also,
the influx of tropical air shows up as deep moist adiabatic sounding
profiles and increasing equilibrium levels to above 150mb.
3) Exceptionally warm cloud depths aiding precipitation efficiency.
The 0 C and -10 C isotherm heights are forecast at 15 kft and 20
kft, respectfully.
4) Lastly, forward-propagating Corfidi vectors (20 kts) are aligned
parallel to the boundary - suggesting training of storms.
Timing: Fortunately, duration of heavy rain should be limited
somewhat by transient nature of the cold front which will sink from
NW to SE through the forecast area. During the day, the best chances
for storms are over the NW third of the CWA. At night, the threat
zone for heavy rain shifts into the SE two-thirds.
Confidence: High that thunderstorms producing excessive rainfall
rates will occur, but low on exact placement because the most likely
scenario is for localized narrow zones -- a county or two wide -- to
be impacted by the enhanced rates.
Thursday...Front exits to the east, taking rain chances with it.
Still warm, though, with highs near 80 F northern CWA to mid 80s
south. Expect lower humidity behind the front, except in to SE where
dewpoints will be slow to fall out of the lower 70s.
Friday...The brief reprieve from shower and thunderstorm chances
ends quickly. Severe weather potential will be dependent on the
degree of instability attained and timing of a cold front. Deep
layer shear is forecast to exceed 35 kts. But with low confidence on
aforementioned parameters...too early to assess the severe threat.
Saturday and Sunday...Dry and cooler behind compact shortwave
trough. Highs in the 70s and lows in the 50s.
Monday...A bit warmer and more humid. Another cold front brings
chances for showers and storms.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
ISSUED AT 1125 PM CDT Mon Sep 5 2016
VFR conditions with fair skies and very warm conditions to prevail the
next 24 plus hours. South winds of 5 to 10 MPH overnight will increase
to 10 to 20 MPH by late morning on Tuesday, then diminish to 5 to 10
MPH after sunset.
&&
.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...RP Kinney
SHORT TERM...RP Kinney
LONG TERM...Uttech
AVIATION...Nichols
Area Forecast Discussion
National Weather Service Indianapolis IN
428 AM EDT TUE SEP 6 2016
.UPDATE...
The Aviation section has been updated below.
&&
.SYNOPSIS...
Issued at 346 AM EDT Tue Sep 6 2016
A warm and humid airmass is in place across central Indiana and
will remain so much of the week. Isolated thunderstorms cannot be
ruled out this afternoon and Wednesday afternoon, with storm
chances increasing late Wednesday night into the end of the week
as a frontal zone moves into the region. The front will finally
move out of the area late Saturday, bringing a cooler and drier
airmass back into the area toward the end of the forecast period.
&&
.NEAR TERM /Today/...
Issued at 346 AM EDT Tue Sep 6 2016
With isolated showers/storms forming yesterday afternoon,
dewpoints remaining in the upper 60s to low 70s, and HRRR
suggesting it, will add a 15 pop for isolated convection mainly
across the northern half of the area this afternoon. Otherwise,
expect some scattered cloud and hot conditions with heat indices
ranging from the mid 90s to around 100 at their peak this
afternoon.
Consensus temperatures looked a couple degrees too cool given
persistence, no change in airmass, and increasing 850 temps today.
&&
.SHORT TERM /Tonight through Thursday Night/...
Issued at 346 AM EDT Tue Sep 6 2016
May again see isolated convection in the afternoon Wednesday with
humid unstable airmass in place. Chances will then ramp up late
Wednesday night as the frontal zone approaches. Appears likely
that the boundary will stall somewhere in the region with a chain
of vort maxes riding along it Thursday into Thursday night. This
may bring multiple rounds of storms to the area toward the end of
the short term and continuing into the long term. Hydro may be the
primary concern with this as the area has been quite damp recently
and there may be at least a period with the 850 jet oriented
normal to the boundary late in the short term, which could set the
stage for some training of storms.
Consensus temperatures appeared to blunt the diurnal temperature
curve a bit and were adjusted accordingly.
&&
.LONG TERM /Friday through Monday/...
Issued at 220 AM EDT Tue Sep 6 2016
Potential for some pretty active weather for the start of the long
term as southwesterly low level flow off the Gulf and leftover
pieces of energy and associated moisture from Newton caught up in
southwest flow aloft, will precede a cold front that a blend has
sweeping across central Indiana Saturday. The 12z ECMWF and its
ensemble mean were 6-12 hours faster than the 00z GFS and its
ensemble mean. Long range precipitable water amounts were over 2
inches along and ahead of the front. With a good combo of lift and
moisture, will accept likely Regional blend pops and mention heavy
rain in the Hazardous Weather Outlook. It may be a bit pre-mature to
put heavy rain in the grids, however.
The Regional blend looks good with something of a blend in timing of
the quicker 12z ECMWF and slower 00z GFS with 40 percent pops
southeast and 20 percent northeast. Thunderstorm threat should be
over prior to 00z Sunday.
Went dry and cooler after Saturday, per the Regional Blend, as high
pressure moves in, in the wake of the front. Afternoon highs in the
lower to mid 80s Friday should only be in the mid and upper 70s
Sunday.
&&
.AVIATION /Discussion for the 060900Z IND TAF Update/...
Issued at 428 AM EDT Tue Sep 6 2016
No changes needed to the TAF.
Previous discussion follows...
Issued at 1200 AM EDT Tue Sep 6 2016
Diurnal cloud development based around 030 expected towards the midday
hours of Tuesday.
Crossover temperatures are within reach during the pre dawn hours of
Tuesday, so there may be some light fog for a few hours around daybreak
Tuesday. A light gradient lends to low confidence of IFR visibility
restrictions at this time.
Light surface winds overnight expected to become 210-230 degrees at 9-12
kts by midday Tuesday.
&&
.IND Watches/Warnings/Advisories...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM...MK
AVIATION...JAS
Area Forecast Discussion
National Weather Service Marquette MI
518 AM EDT TUE SEP 6 2016
.SHORT TERM...(Today and tonight)
Issued at 517 AM EDT TUE SEP 6 2016
WV imagery and RAP analysis indicated sw mid/upper level flow
from the cntrl plains to the nrn Great Lakes between a broad trough
over the wrn CONUS and a ridge from the Gulf of Mexico to the ern
Great Lakes. Strong 850 mb moisture transport as well as several
shrtwvs in the sw flow supported clusters of shra/tsra from srn MN
into wrn Upper Michigan and Lake Superior. A more prominent upstream
shrtwv over ern SD supported an MCS from se SD into sw MN. At the
surface, srly flow continued ahead of a slow moving front from cntrl
MN to low pres over northeast KS.
Today, radar trends suggest that sct/nmrs shra/tsra from will
gradually spread through the west half of Upper Michigan through mid
morning. As the SD shrtwv moves toward the area, and daytime heating
increases toward midday, expect the shra/tsra to increase in
coverage btwn 14z-17z with the convection spreading toward the ern
cwa. With some thinning in the clouds at times and surface heating
allowing temps to recover to near 80, MLCAPE values could recover
into the 1000-1500 J/Kg range. However, there is uncertainty with
the amount of heating/instability that will develop given the
extensive amount of ongoing convection and leftover clouds into the
early afternoon. Nevertheless, with 0-6km shear values into the 40-
50 knot range, there will be a risk of severe storms with damaging
winds and large hail.
Tonight, models suggest that there may be a lull in the shra/tsra as
the main shrtwv moves off to the ene with weak qvector div and
subsidence in its wake. However, chance pops were retained given the
lingering instability and uncertainty with the development/location
of additional weak shrtwvs moving into the area by late evening and
overnight.
&&
.LONG TERM...(Wednesday through Monday)
Issued at 419 AM EDT TUE SEP 6 2016
Active weather pattern in store from midweek into early next week as
the upper pattern is transitioning from the amplified western
trough/eastern ridge to a more zonal pattern across the CONUS.
SW upper flow on Wed into Wed evening will allow another series of
shortwaves to ride along stalled frontal boundary which will be just
south of Upper Mi during the day. There remain some model
differences in timing/position of these shortwaves but with the
proximity of front and track of shortwaves generally near the
southern portion of forecast area along with PWs near 2 inches expect
the southeast half of Upper Mi to have greatest chance of getting
rainfall and perhaps a potential of some heavier rainfall given high
PWs. Some of model guidance seems to suggest that the northwest half
of the cwa could see little to no pcpn Wed-Wed evening farther away
from frontal boundary and better shortwave dynamics and more
influenced by anticyclonic NE flow around sfc high over Northern
Ontario.
Models consistent showing a stronger shortwave from the Northern
Plains poised to move across the Upper Great Lakes late Wed night
into Thu. DPVA...upper diffluence and waa/isentropic ascent ahead of
the shortwave along with PWs aoa 1.5 inches will favor the northern
tier counties and particularly the nw portion of the cwa for the best
chc of rainfall Wed night into Thu morning.
Broad mid-upper level ridging and assoc Q-vector divergence/
subsidence in the wake of the shortwave Thu afternoon will allow for
a period of mostly dry weather Thu afternoon into Friday morning.
00z models trending much stronger with next shortwave approaching
from the Northern Plains in a zonal flow aloft for late Fri into Sat.
Deep layer q-vector convergence will bring another round of
showers/sct TS to the area late Friday into Saturday. Northwest winds
could get gusty on Sat with tightening gradient behind deepening sfc
low fcst to lift ne of Lake Superior Sat afternoon/evening. Model
soundings would suggest the potential for northwest wind gusts to 30
mph over the northern tier counties of the cwa and gusts to 40 mph
may even be possible over the tip of the Keweenaw and for shoreline
areas from Munising eastward. Would not be shocked to see a period of
gales over the eastern half of Lake Superior Sat afternoon into Sat
evening.
Ridging and subsidence behind Saturday`s shortwave and
assoc cold frontal passage should result in drier/cooler weather
later Sat night into Sun night. There is plenty of model uncertainty
with timing of next shortwave due to move in for early next week so
will continue to utilize model consensus pops next Mon into Tue.
Temps should remain near or slightly above normal from Wed through
Fri but then fall slightly below normal for the weekend in the wake
of the cold fropa Fri night. Dewpoints in the mid to upper 60s into
will make it feel quite humid into Thu, but then dewpoints should
fall back into a more comfortable 50s range for Fri into early next
week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 145 AM EDT TUE SEP 6 2016
As a steady SW flow advects very moist air into the Upr Great Lks,
expect conditions at the TAF sites to deteriorate into the MVFR
range. There wl also be clusters of showers and TS moving thru the
area. The most nmrs showers overngt wl impact IWD and CMX, but then
SAW later today ahead of a slowly aprchg cold fnt that wl pass the
wrn sites later today. With some daytime heating, SAW should see an
improvement to VFR ahead of the fnt/cluster of showers. In the wake
of the fropa, conditions should improve to VFR at CMX and IWD.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 517 AM EDT TUE SEP 6 2016
Winds through Fri night are expected to remain mainly at 20 kts or
less. The strongest winds will be Saturday with gusts up to 30 knots
out of the north and northwest as a deepening low pressure system
lifts to the e of Lake Superior. No gales are expected but cannot
rule out gale potential Saturday if the low pressure continues to
trend stronger.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Voss
AVIATION...KC
MARINE...JLB
Area Forecast Discussion
National Weather Service Norman OK
321 AM CDT TUE SEP 6 2016
.DISCUSSION...
Shortly after 3 am, most of Oklahoma and western north Texas were
void of cloud cover. Per RAP soundings, low clouds should form
around or before sunrise and spread northward. Clouds that form
will decrease through the morning with some Cu through the
afternoon.
Most of the forecast area should remain dry through the day, however
an isolated storm or two may form mainly across southwestern Oklahoma
during the late afternoon/evening with better chances to our
west.
A mid and upper level ridge, centered over Arkansas and Louisiana, will
gradually build west through about Thursday, so summer-like
temperatures will prevail. However, shower and storm chances will
increase Wednesday into Thursday as the remnants of Hurricane
Newton moves north and east over the next several days. Much
stronger upper level winds will remain west and north of the
area, but with an increase in mid to upper level moisture,
scattered showers and storms should form with better chances
across western and northern Oklahoma. The remnants of Newton will
track far enough north that it will accelerate and just skirt
northern parts of Oklahoma Thursday into Friday.
Meanwhile, a trough is expected to move quickly across the northern
Rockies and Plains Friday into Saturday. This system will push
a front into the southern Plains and bring better chances
of widespread showers and storms late Friday into early Saturday.
The GFS is a little slower with the frontal timing, so some
adjustments to likely/higher POPs may be needed.
Much needed relief from the heat and humidity will arrive just in
time for the weekend. Another system will begin to approach the
area late in the weekend into Monday. Moisture return and southerly
winds, may result in additional showers and storms early next
week. If the ECMWF is correct, a preview of fall-like temperatures
may arrive around Tuesday or Wednesday or next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 92 74 92 74 / 0 10 20 30
Hobart OK 93 74 93 73 / 10 20 30 30
Wichita Falls TX 95 74 96 75 / 0 0 10 10
Gage OK 91 73 90 69 / 10 20 40 20
Ponca City OK 93 76 92 75 / 0 0 20 50
Durant OK 93 73 94 74 / 0 0 0 0
&&
.OUN Watches/Warnings/Advisories...
OK...None.
TX...None.
&&
$$
Area Forecast Discussion
National Weather Service Albuquerque NM
538 AM MDT TUE SEP 6 2016
.AVIATION...
12Z TAF CYCLE
Very active period next 24hrs as a deep tap of tropical moisture
surges north into NM. Storms with +RA and gusty outflows will
again be possible this afternoon through tonight. Still expecting
low cigs/vsbys to develop around KLVS. Showers and storms will
begin to develop by 18z and continue through much of tonight. MVFR
to IFR CIGS in the stronger storms. CHJ
&&
.PREV DISCUSSION...328 AM MDT TUE SEP 6 2016...
.SYNOPSIS...
Widespread storms are expected today and tonight mainly east of
the Continental Divide. Abundant amounts of moisture will lead to
heavy rain producing storms and potentially flash flooding. A
Flash Flood Watch is in effect for much of eastern New Mexico this
afternoon and overnight. In addition to the flooding concerns,
some storms may become briefly severe, producing hail and high
winds. Remnants of Hurricane Newton will move into western New
Mexico Wednesday and Wednesday night. More heavy rain is
possible, though now favoring the southwest and west central
mountains.
&&
.DISCUSSION...
Vort max associated with the thunderstorm cluster in Mexico 24-hours
ago has, as expected, shifted northward and produced yet another
cluster of thunderstorms in Mexico ahead of Hurricane Newton. There
is some concern this morning that the disturbance/vort max that will
be associated with the latest thunderstorm cluster will be a little
further west than what models indicate as it shifts over NM today.
This could mean greater storm coverage between the ContDvd and the
central mtn chain than forecast. Nonetheless, still believe the
greatest risk for heavy rain and flash flooding is along and east of
the central mtn chain this aftn/eve. Thunderstorms have persisted
much of the night across north central and northeast NM and some
areas have received quite a bit of rain. Therefore, have opted to
expand the Flash Flood Watch northward to the Colorado border to
cover these areas that now have saturated soils. Additionally, the
NAM, HRRR and local WRF are also showing signals of heavy rain
producing storms across the northeast. Though storm motion will be
pretty fast, training storms will be possible, similar to last night.
Secondary to the flash flooding concerns, models also show quite a
bit of instability and shear. Thus a few strong to severe storms are
possible again today as well.
As the vort max shifts across eastern NM, models have been
consistent at developing a cluster or broken line of storms across
the east central and southeast plains this evening. This is where
confidence is highest that heavy rainfall may produce problems as
copious amounts of moisture will be in place with ample lift.
Newton`s track appears to be a bit further east this morning and
therefore its remnants cross NM a bit sooner than originally
expected. By Wed afternoon, the center of Newton should be over SE
AZ, and as it shifts eastward into NM Wed night, it should open into
a trough. Heavy rainfall amounts are expected with Newton`s
remnants, mainly across the southwest and west central mountains.
Rainfall will be persistent, lingering pretty much all day Wednesday
and Wed night. Flash flood watches will likely be needed for this
area.
As the system weakens, it will continue to cross NM on Thursday, and
though it will cross slowly thru Thursday night, it no longer looks
like it will stall over the state. Additionally, it appears much
drier air will move in behind the system. Thus, after Thursday
morning, rain chances really taper off for the latter part of
Thursday and early Friday.
A back door front is still slated to come down the plains, though it
looks to be a bit slower, arriving late Friday afternoon across the
NE and quickly pushing south and west Friday night. Storms are still
possible along and behind the front across the east Friday evening,
though models are a bit less bullish this morning - likely owing to
the drier air aloft behind Newton`s remnants. Still looking for a
healthy east canyon wind Saturday morning in the Rio Grande Valley
replenishing low level moisture across the west. Yet another front
may arrive on Tuesday. Might start to feel like Fall.
34
&&
.FIRE WEATHER...
Moisture surges today and later Wednesday will bring widespread
wetting rains to northern and central New Mexico into Thursday.
There will be areas of heavy rain and localized flash flooding.
A ridge of high pressure to our east and a trough of low pressure to
our west are allowing increased moisture to advect north and
northeast into NM. An upper level disturbance over northern Mexico
will move northeast across the state today, significantly enhancing
shower and thunderstorm coverage through tonight. There will be
heavy rain with the potential for localized flash flooding. Only the
far northwest will be rainfree today with minimum RH values in the
teens. Ventilation will be mostly good to excellent. Highs today
will be cooler than Monday, close to normal.
The drying trend across the north for Wednesday is not as pronounced
now as the past few days have shown. This looks to be the result of
the faster moving remnants of Hurricane Newton, which brings a
healthy dose of moisture into our southwest zones by the end of
Wednesday. Wetting rains will be limited across the northern half of
our zones Wednesday, but will occur across the southern tier, and
rain could be heavy in the West Central Highlands. Vent rates will
take a hit Wednesday with mostly fair to good rates, with an area of
poor ventilation over the West Central Highlands. Highs will
continue to trend down, mostly below normal except for the
northeast.
The bulk of the precipitation from the remains of Newton will cross
NM Wednesday night. The closed low will quickly open up to a trough
of low pressure Thursday with precipitation beginning to diminish.
Ventilation will be fair to good Thursday, but again poor over the
West Central Highlands, and perhaps joined by small portions of the
northeast. Maximum RH will be fair to poor Wednesday night.
Friday will be dry with more sunshine and higher temperatures,
mostly a little above normal. A back door cold front is still
scheduled to arrive across the east Friday night and then spill into
the Rio Grande Valley Saturday. This fresh supply of low level
moisture will bring a return of showers and storms Friday night to
the east and across the south on Saturday.
Moisture will begin to return to the west Sunday, and expand north
and east Monday and especially Tuesday.
CHJ
&&
.AVIATION...
06Z TAF CYCLE
Very active period next 24hrs as a deep tap of tropical moisture
surges north into NM. Storms w/ +RA and gusty outflows continue
to move E/NE across northeast NM late tonight, while a few cells
attempt to push north into south central areas. Expecting low
cigs/vsbys to develop around KLVS where +RA occurred earlier.
Cigs near 015 also possible around KROW as occurred the past few
nights, but confidence not as high for tonight. Tuesday will see
storms develop by 18Z then move north into large clusters with
MVFR and brief IFR excursions from +RA.
Guyer
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from noon MDT today through late tonight for the
following zones... NMZ515-526>540.
&&
$$
Area Forecast Discussion
National Weather Service Cleveland OH
1154 AM EDT TUE SEP 6 2016
.SYNOPSIS...
A ridge of high pressure will remain over the region into tonight.
The high will weaken by Wednesday which will allow waves of low
pressure to move across the Central Great Lakes Thursday into the
weekend.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Update...The HRRR shows isolated convection developing across the
area this afternoon. Not sure I buy it completely but capes do
get up to around 2000j/kg on the new NAM12 for the afternoon and
given the current isolated activity east seems reasonable to have
a slight chance pops most locations for the afternoon.
original...Short range models were correct in developing a few
showers this morning. Seems there is enough divergence aloft
combined with some moisture advection to generate lift for the
showers. Afternoon heating combined with the factors mentioned
above will likely generate some isolated thunder for central and
southeastern portions of the County Warning Area (CWA).
It will be another hot day. Temperatures should be another degree
or two warmer than yesterday with increased humidity.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
Humidity levels will increase on Wednesday as the southerly flow
increases a bit more. It appears 7H temperatures decrease a bit
on Wednesday so we are feeling a bit more confident to mention
some low chances of thunder. Thunderstorm chances will increase
Thursday afternoon/evening as a weakening cold front sags into the
area. It appears there will be a lull in the thunderstorm
activity Thursday night into early Friday as we await the next
piece of low pressure. This area of low pressure will track along
the stalled frontal boundary that may be located across the
central portions of the CWA. This should help to generate another
round of thunderstorms Friday afternoon into Friday night. Still
some uncertainty where the heaviest swath of rainfall will be
located so will not hoist any flood concerns. However some locally
heavy rainfall will be possible.
It will remain hot and humid across the region Wednesday into
Thursday. Still concerned that a heat headline may be needed
across portions of the region west of I-71. Best location for
exceeding heat indices of 100 degrees would be across NW Ohio.
Will place the mention in the HWO and let later shifts take
another look at this potential. Cooler on Friday with the next
wave of low pressure increasing cloud cover over the area. Highs
Friday should dip to within a couple degrees of 80.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
The pattern becomes less amplified and we begin to move systems
across the region faster. One such system will be a shortwave from
western Canada that will dig across the Northern Plains and cross
the Great Lakes over the weekend. This is projected to take a cold
front across the area on Saturday night. A seasonally cool airmass
follows in its wake...but with high pressure building in from the
southwest...vs northwest...the cool down will be short lived and the
flow will begin to back to the southwest for Monday. Expecting
enough cloud cover prior to the cold front Saturday to cap highs in
the lower 80s. Went with the warmer guidance for Sunday with the
position of the high...which tops us out in the lower and mid 70s.
Will gain a few more degrees back on Monday. Night lows in the 50s
inland.
&&
.AVIATION /12Z Tuesday THROUGH Saturday/...
High pressure beginning to give way to an advancing system from
the upper Midwest that will cross the area Thursday. There is an
outside chance of a shower/thunderstorm today but nothing to
include yet in the TAFs. VFR conditions expected with an afternoon
cumulus field that will become BKN for a time today. Light/variable
winds from overnight will become light southwest...with minor
gusts across TOL/FDY.
OUTLOOK...Periodic non-VFR possible Thursday through Saturday.
&&
.MARINE...
High pressure will still be overhead for today and Wednesday with
west-southwest winds of 10 to 15 knots. As the high shifts east and
a cold front approaches...winds Thursday will increase to 15 to 20
knots. Waves will respond and will be borderline small craft
advisory conditions. The fronts timing is on track for Thursday
evening...with winds diminishing behind the front and a brief stay
by high pressure on Friday. A warm front Friday night followed by a
cold front Saturday night brings the next chance for elevated winds
and possible small craft conditions.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Mullen
NEAR TERM...TK/Mullen
SHORT TERM...Mullen
LONG TERM...Oudeman
AVIATION...Oudeman
MARINE...Oudeman
Area Forecast Discussion
National Weather Service Cheyenne WY
520 AM MDT TUE SEP 6 2016
.SHORT TERM...(Today through Thursday)
Issued at 520 AM MDT Tue Sep 6 2016
Forecast challenges deal with severe thunderstorm potential today
followed by strong winds/fire weather conditions Wednesday and
Thursday.
As for severe thunderstorm potential today, NAM and GFS CAPE
showing a ribbon of around 1500 J/KG across Laramie County and the
southern Panhandle. Could be an issue with a capped environment
out in the southern Panhandle as GFS soundings show a strong cap
that will be really hard to break today. Better chances are over
here towards Cheyenne and Wheatland today where we will be better
able to break the cap. Impressive shear seen on the CYS sounding
on the GFS with southeasterly surface winds at 15kts and an upper
level jet near 95kts from the southwest. HRRR simulated radar
showing a supercell developing in southern Platte County that
moves northeast into Goshen County this afternoon after 21Z. Did
add severe thunderstorm wording in the forecast for this
afternoon. There is a tornado threat today with LCLs around
4500-5000 feet and SREH above 224 m2/s2. Day shift will need to
keep this in mind as we move into the afternoon.
Reluctant to remove the overnight fog tonight as we have seen it
happen the last three nights. Will leave it in for now and see
what the 12Z model guidance shows. Low level winds are forecast to
shift to the west, but surface winds remain out of the south. Have
a strong low level inversion, especially over the southern
Panhandle, so areas of fog are a threat again tonight.
Westerly winds on the increase Wednesday morning as strong
shortwave tracks across eastern Montana and northern Wyoming. GFS
700mb winds increase to 35kts and .5km agl humidities drop to
around 15 percent through the morning. Perfect setup for fire
weather conditions for our zones along and west of the Laramie
Range. Did issue a Fire Weather Watch for much of southeast
Wyoming for Wednesday.
Thursday looks even windier as 700mb winds increase to 40kts
across Carbon and Albany Counties. Critical fire weather
conditions could be further east with these strong winds
downsloping off the Laramie Range. Do think we will need fire
headlines for Thursday as well.
.LONG TERM...(Thursday night through Monday)
Issued at 520 AM MDT Tue Sep 6 2016
An upper trof will pass by Thursday night and Friday with a cool
front crossing the CWA Thursday night. Mainly dry and cooler
conditions for Friday then continued mild Saturday under wnw flow
aloft. Upper flow gradually backs to westerly and southwesterly
Sunday through Monday as the next upper system digs over the
northwest part of the country. Warm on Sunday then still looking
like a pretty good cold front passing across on Monday. Showers
should develop in post-frontal upslope flow Monday as the air mass
moistens.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 520 AM MDT Tue Sep 6 2016
Fairly widespread MVFR/IFR cigs east of the mtns this morning and
likely persisting across much of the Panhandle through the day in
moist upslope flow. Sctd showers and tstrms over the plains this
afternoon and evening.
&&
.FIRE WEATHER...
Issued at 520 AM MDT Tue Sep 6 2016
Elevated fire weather conditions along the Wyoming/Colorado border
today with gusty southwest winds and afternoon humidities falling
to around 15 percent in some areas. Overall though...think our
better chances for more widespread critical fire weather
conditions will be Wednesday as low pressure tracks across Montana
during the day. A Fire Weather Watch has been issued for a large
portion of southeast Wyoming for Wednesday with afternoon
humidities falling below 15 percent and winds gusting in excess of
30MPH. Stronger winds expected Thursday and critical fire weather
conditions could spread further east...possibly into the Panhandle
as a strong downsloping wind off the Laramie Range sets up.
&&
.CYS Watches/Warnings/Advisories...
WY...Fire Weather Watch from Wednesday afternoon through Wednesday
evening for WYZ301-303-304-306-308-309.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Quad Cities IA IL
642 AM CDT TUE SEP 6 2016
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 135 AM CDT Tue Sep 6 2016
Much of the area was clear during the early morning hours, with
some clouds across far northeast Iowa. Showers and thunderstorms
continued well to the northwest, from eastern Nebraska into
northern Wisconsin. Early morning temperatures were mainly in the
low to mid 70s.
&&
.SHORT TERM...(Today and Tonight)
ISSUED AT 135 AM CDT Tue Sep 6 2016
The main forecast issues in the short term period are the heat and
humidity today, and coverage/timing of thunderstorms late this
afternoon and tonight.
In the near term, recent runs of the HRRR hint at some isolated
showers across the north this morning, and there have been some
light echoes developing to the north of the forecast area.
However, with such low probabilities have kept rain out of the
forecast and we can re-evaluate through daybreak.
For today`s highs, have boosted Monday`s temps 2 to 3 degrees most
areas with favorable southwest flow and warmer 850mb temps. That
yields highs in the 87 to 91 degree range. Based on trends upstream
and Monday`s observations, dewpoints in the 71 to 74 range look
reasonable for today, yielding widespread afternoon heat indices
of 95 to 100 degrees. There may be a few locations near or
slightly above the 100 degree advisory criteria for a few hours,
but these higher readings are not expected to be widespread enough
to warrant an advisory. We anticipate handling with a special
weather statement.
Showers and storms could spill into the Highway 20 corridor late
this afternoon, but are more favored later this evening and
overnight, especially across the northwest half of the forecast
area, associated with the nose of a 35 to 40 kt low level jet. The
overall severe weather threat is low, although gusty winds will be
possible with a few storms in the north.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 135 AM CDT Tue Sep 6 2016
Wednesday...Threat for heavy rainfall rates and localized flash
flooding are the main concerns. From a synoptic standpoint, the
atmospheric setup is quite favorable for extremely efficient rain
producing thunderstorms with rainfall rates possibly in excess of
2"/hr. There is also a marginal risk for severe thunderstorms.
Models are forecasting several key ingredients that are typically
associated with Predecessor Rainfall Events:
1) Moist 850-500mb sub-tropical flow from the western Gulf into the
Midwest manifest as an anomalously strong Atmospheric River. Put
into historical context, the NAEFS IVT (WV transport) is forecasting
near record values for September based on a 30-yr model climatology.
2) Additional mid-upper level moisture flux contribution from a
tropical system entering into SE Arizona and NW Mexico, could raise
PWATs near 2.25" -- also near record territory for early September.
The tropical system`s contribution to increased PWATs and mid to
upper level saturation is corroborated by 700-500mb advection of
greater than 90% RH from the Southwest U.S. into the Midwest. Also,
the influx of tropical air shows up as deep moist adiabatic sounding
profiles and increasing equilibrium levels to above 150mb.
3) Exceptionally warm cloud depths aiding precipitation efficiency.
The 0 C and -10 C isotherm heights are forecast at 15 kft and 20
kft, respectfully.
4) Lastly, forward-propagating Corfidi vectors (20 kts) are aligned
parallel to the boundary - suggesting training of storms.
Timing: Fortunately, duration of heavy rain should be limited
somewhat by transient nature of the cold front which will sink from
NW to SE through the forecast area. During the day, the best chances
for storms are over the NW third of the CWA. At night, the threat
zone for heavy rain shifts into the SE two-thirds.
Confidence: High that thunderstorms producing excessive rainfall
rates will occur, but low on exact placement because the most likely
scenario is for localized narrow zones -- a county or two wide -- to
be impacted by the enhanced rates.
Thursday...Front exits to the east, taking rain chances with it.
Still warm, though, with highs near 80 F northern CWA to mid 80s
south. Expect lower humidity behind the front, except in to SE where
dewpoints will be slow to fall out of the lower 70s.
Friday...The brief reprieve from shower and thunderstorm chances
ends quickly. Severe weather potential will be dependent on the
degree of instability attained and timing of a cold front. Deep
layer shear is forecast to exceed 35 kts. But with low confidence on
aforementioned parameters...too early to assess the severe threat.
Saturday and Sunday...Dry and cooler behind compact shortwave
trough. Highs in the 70s and lows in the 50s.
Monday...A bit warmer and more humid. Another cold front brings
chances for showers and storms.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
ISSUED AT 640 AM CDT Tue Sep 6 2016
VFR conditions will continue through much of the TAF period with
an increasing southwest wind. Thunderstorms are expected to impact
KDBQ and KCID later tonight, and have added Prob30 groups. Lesser
chance of storms affecting KMLI and KBRL before 12z.
&&
.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...RP Kinney
SHORT TERM...RP Kinney
LONG TERM...Uttech
AVIATION...RP Kinney
Area Forecast Discussion
National Weather Service Lincoln IL
940 AM CDT TUE SEP 6 2016
.UPDATE...
Issued at 940 AM CDT Tue Sep 6 2016
Current forecast is on track and only required minor tweaks. Clear
skies this morning will start to fill in with the diurnal cumulus
over the next couple hours. Similar to yesterday, isolated
convection should start to develop around midday, with the latest
runs of the HRRR focusing on the Danville-Litchfield corridor with
the best chances through the afternoon. Some locally heavier
showers are possible as precipitable water values rise to around 2
inches this afternoon per latest RAP guidance. Any isolated
showers will help lower temperatures in a few lucky areas, but
overall highs should reach the lower 90s, with heat index values
in the 100-102 range.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 317 AM CDT Tue Sep 6 2016
Ridge of high pressure extending from the eastern Great Lakes to the
Gulf Coast will continue to dominate the weather across central
Illinois today. A warm/moist southerly flow on the back side of the
high will help boost high temperatures into the lower 90s. These
very warm readings combined with dewpoints in the lower to middle
70s will produce maximum heat index values of around 100 degrees.
Despite lack of synoptic scale forcing, several of the high-res
models are suggesting isolated convection may develop this afternoon
in the moderately unstable and uncapped airmass. Since a few
showers developed across the E/SE yesterday, have opted to include
isolated thunderstorms along/east of I-55 this afternoon. Any
diurnal convection will quickly dissipate toward sunset, with dry
conditions expected tonight.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 317 AM CDT Tue Sep 6 2016
Strong 594dm 500mb upper ridge will control the weather into
Wednesday, resulting in another hot day with highs reaching the
lower 90s. While cold front will remain well W/NW of the area, have
added isolated afternoon thunderstorms to the forecast due to
favorable instability and potential presence of mesoscale outflow
boundaries. As a short-wave trough tracking through the Plains
approaches, it will give the cold front a solid push eastward
Wednesday night into Thursday. Given decent convergence along the
boundary, increasing upper support, and deep-layer moisture
characterized by precipitable water values greater than 2
inches...have gone with high chance to likely PoPs along/northwest
of a Danville to Taylorville line Wednesday night. Further
southeast, precip may hold off until Thursday morning, so have
only gone with slight chance PoPs along/south of I-70.
00z Sep 9 models now show the front pushing further south than
previously forecast. NAM/GFS/ECMWF/GEM all indicate boundary will
sink into southern Illinois before stalling Thursday afternoon.
Given good model agreement, have dropped rain chances along/north of
I-72 during the afternoon. Most models keep the boundary south of
the area Thursday night, with the most widespread convection focused
across southern Illinois. The ECMWF is the lone exception,
suggesting the boundary will lift back northward and spread rain as
far north as northern Illinois overnight. Despite the ECMWF being
the odd model out, it is consistent with its previous runs...unlike
the other models that have shifted much further south with the
precip. As a result of this consistency, have spread rain chances
back across the entire CWA Thursday night...with PoPs ranging from
20-30 across the far north to 50 across the south.
Highest rain chances are still on target for Friday and Friday night
as a stronger short-wave trough finally pushes the persistent
frontal boundary out of the region. Have gone with likely PoPs
across the board accordingly. After that, front pushes well to the
east over the weekend...leading to cooler/drier weather for
Saturday through Monday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 634 AM CDT Tue Sep 6 2016
VFR conditions likely across the central Illinois terminals
through the 12Z TAF valid time. Diurnal cumulus buildup with bases
around 4000 feet AGL will produce scattered to broken coverage
during the afternoon. Isolated thunderstorms will be possible, but
coverage not expected to be high enough to warrant mention in TAFs
at this time. Cloud cover will decrease after sunset. Winds S up
to 10 kts...becoming SSW 10-15 kts with gusts to 20 kts after 17Z.
Winds decreasing to under 10 kts after 01Z.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Onton
Area Forecast Discussion
National Weather Service Indianapolis IN
1059 AM EDT TUE SEP 6 2016
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 346 AM EDT Tue Sep 6 2016
A warm and humid airmass is in place across central Indiana and
will remain so much of the week. Isolated thunderstorms cannot be
ruled out this afternoon and Wednesday afternoon, with storm
chances increasing late Wednesday night into the end of the week
as a frontal zone moves into the region. The front will finally
move out of the area late Saturday, bringing a cooler and drier
airmass back into the area toward the end of the forecast period.
&&
.NEAR TERM /Today/...
Issued at 1007 AM EDT Tue Sep 6 2016
This morning`s upper air indicates mid level temperatures are a
little cooler today than they were yesterday, especially over the
eastern and southeastern zones. As a result, will expand the small
chance PoPs for air mass type convection into these areas as well
for this afternoon.
Previous discussion follows.
With isolated showers/storms forming yesterday afternoon,
dewpoints remaining in the upper 60s to low 70s, and HRRR
suggesting it, will add a 15 pop for isolated convection mainly
across the northern half of the area this afternoon. Otherwise,
expect some scattered cloud and hot conditions with heat indices
ranging from the mid 90s to around 100 at their peak this
afternoon.
Consensus temperatures looked a couple degrees too cool given
persistence, no change in airmass, and increasing 850 temps today.
&&
.SHORT TERM /Tonight through Thursday Night/...
Issued at 346 AM EDT Tue Sep 6 2016
May again see isolated convection in the afternoon Wednesday with
humid unstable airmass in place. Chances will then ramp up late
Wednesday night as the frontal zone approaches. Appears likely
that the boundary will stall somewhere in the region with a chain
of vort maxes riding along it Thursday into Thursday night. This
may bring multiple rounds of storms to the area toward the end of
the short term and continuing into the long term. Hydro may be the
primary concern with this as the area has been quite damp recently
and there may be at least a period with the 850 jet oriented
normal to the boundary late in the short term, which could set the
stage for some training of storms.
Consensus temperatures appeared to blunt the diurnal temperature
curve a bit and were adjusted accordingly.
&&
.LONG TERM /Friday through Monday/...
Issued at 220 AM EDT Tue Sep 6 2016
Potential for some pretty active weather for the start of the long
term as southwesterly low level flow off the Gulf and leftover
pieces of energy and associated moisture from Newton caught up in
southwest flow aloft, will precede a cold front that a blend has
sweeping across central Indiana Saturday. The 12z ECMWF and its
ensemble mean were 6-12 hours faster than the 00z GFS and its
ensemble mean. Long range precipitable water amounts were over 2
inches along and ahead of the front. With a good combo of lift and
moisture, will accept likely Regional blend pops and mention heavy
rain in the Hazardous Weather Outlook. It may be a bit pre-mature to
put heavy rain in the grids, however.
The Regional blend looks good with something of a blend in timing of
the quicker 12z ECMWF and slower 00z GFS with 40 percent pops
southeast and 20 percent northeast. Thunderstorm threat should be
over prior to 00z Sunday.
Went dry and cooler after Saturday, per the Regional Blend, as high
pressure moves in, in the wake of the front. Afternoon highs in the
lower to mid 80s Friday should only be in the mid and upper 70s
Sunday.
&&
.AVIATION /Update to 061200z KIND TAF/...
Issued at 1056 AM EDT Tue Sep 6 2016
VFR with winds near or below 10 kts through the period.
With a few cumulus already forming, expect scattered cumulus
around 4000 feet the rest of the day.
Instability may spark an isolated storm at peak heating this
afternoon but coverage and location is too uncertain so no mention
is made in TAF.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD/JAS
SHORT TERM...NIELD
LONG TERM...MK
AVIATION...TUCEK
Area Forecast Discussion
National Weather Service Louisville KY
1008 AM EDT TUE SEP 6 2016
...Forecast Update...
Issued at 1005 AM EDT Tue Sep 6 2016
Removed the morning fog wording from the zones. The HRRR has been
insistent on some cells developing along the I-65 corridor this
afternoon. Yesterday had some over southeast IL. Latest model
precipitable water guidance indicates this area as along the edge of
a more moist airmass to the west. However, we also have an upper
ridge axis over that region, which should limit destabilization.
Also, latest total PW map from SSEC/WISC shows the more moist air
farther west. Combingin this info, cannot rule out an isolated small
shower, but will keep the main public forecast at less than 15
percent rain chance for now...that is, keep the ongoing forecast
with silent pops. Will monitor trends and amend if necessary.
Issued at 605 AM EDT Tue Sep 6 2016
Updated the forecast to add patchy fog for a few hours this
morning. Any light fog should quickly burn off after sunrise.
.SHORT TERM (Now through Wednesday)...
Issued at 245 AM EDT Tue Sep 6 2016
Hot and mostly dry conditions are expected today through Wed as
strong upper level ridging continues to influence our weather. While
we saw a few isld showers pop up yesterday afternoon, feel chances
for that happening today will be even less with greater capping
noted in soundings. Still won`t go with a zero POP, but think rain
chances are very slim.
Wed the ridging will back off a little and we may see a subtle
shortwave round the northern side which could spark very isld
convection. Went with only 10% POP since anything that does form
would be very isld.
Temperatures both today and Wed will soar into the lower 90s. With
dewpts in the upper 60s/lower 70s, max afternoon heat indices will
range through the mid to upper 90s. Low temps should fall into the
mid 60s to lower 70s.
.LONG TERM (Wednesday Night through Monday)...
Issued at 250 AM EDT Tue Sep 6 2016
Thursday - Saturday...
A weak front will approach the area Thu and become nearly stationary
over the region for Fri. Models vary on exactly where it will
settle over the region but most are near the Ohio River or north.
This will bring shower/storms to southern IN/central KY starting on
Thu and continue through Fri as multiple waves ride along the
boundary producing periodic rounds of scattered showers/storms. With
sfc temps remaining fairly warm in the upper 80s/lower 90s and a bit
more speed shear in the wind column, think that a few strong storms
may be possible Thu/Fri.
Fri night the boundary will lift north as a warm front before a
strong cold front and upper trough push through the region late Sat.
Will need to watch the timing on convection associated with this
front as wind shear looks decent enough to produce strong to
possibly severe storms given ample CAPE. Sat temps will be dependent
on timing of the front and storms as well with a wide range of high
temps possible at this point.
Sunday - Monday...
Sfc high pressure and a more zonal flow aloft look to dominate the
Ohio Valley for the beginning of next week. Expect cooler temps
behind Sat`s cold front with highs dropping back into the upper
70s/lower 80s for early next week. Night time lows will range from
the mid 50s to lower 60s.
&&
.AVIATION (12Z TAF Update)...
Issued at 630 AM EDT Tue Sep 6 2016
Some transient fog will affect BWG over the next couple of hours.
This will drop visibility as low as a half mile at times. The fog
should dissipate shortly after sunrise. Thereafter, VFR conditions
are expected at the TAF sites for the rest of the forecast period.
Winds will be out of the south to southwest and will increase to 7-
10 knots by early afternoon. Scattered cu is expected to develop
once again today.
&&
.LMK Watches/Warnings/Advisories...
KY...NONE.
IN...NONE.
&&
$$
Updates........RJS/AMS
Short Term.....AMS
Long Term......AMS
Aviation.......EER
Area Forecast Discussion
National Weather Service Marquette MI
740 AM EDT TUE SEP 6 2016
.SHORT TERM...(Today and tonight)
Issued at 517 AM EDT TUE SEP 6 2016
WV imagery and RAP analysis indicated sw mid/upper level flow
from the cntrl plains to the nrn Great Lakes between a broad trough
over the wrn CONUS and a ridge from the Gulf of Mexico to the ern
Great Lakes. Strong 850 mb moisture transport as well as several
shrtwvs in the sw flow supported clusters of shra/tsra from srn MN
into wrn Upper Michigan and Lake Superior. A more prominent upstream
shrtwv over ern SD supported an MCS from se SD into sw MN. At the
surface, srly flow continued ahead of a slow moving front from cntrl
MN to low pres over northeast KS.
Today, radar trends suggest that sct/nmrs shra/tsra from will
gradually spread through the west half of Upper Michigan through mid
morning. As the SD shrtwv moves toward the area, and daytime heating
increases toward midday, expect the shra/tsra to increase in
coverage btwn 14z-17z with the convection spreading toward the ern
cwa. With some thinning in the clouds at times and surface heating
allowing temps to recover to near 80, MLCAPE values could recover
into the 1000-1500 J/Kg range. However, there is uncertainty with
the amount of heating/instability that will develop given the
extensive amount of ongoing convection and leftover clouds into the
early afternoon. Nevertheless, with 0-6km shear values into the 40-
50 knot range, there will be a risk of severe storms with damaging
winds and large hail.
Tonight, models suggest that there may be a lull in the shra/tsra as
the main shrtwv moves off to the ene with weak qvector div and
subsidence in its wake. However, chance pops were retained given the
lingering instability and uncertainty with the development/location
of additional weak shrtwvs moving into the area by late evening and
overnight.
.LONG TERM...(Wednesday through Monday)
Issued at 419 AM EDT TUE SEP 6 2016
Active weather pattern in store from midweek into early next week as
the upper pattern is transitioning from the amplified western
trough/eastern ridge to a more zonal pattern across the CONUS.
SW upper flow on Wed into Wed evening will allow another series of
shortwaves to ride along stalled frontal boundary which will be just
south of Upper Mi during the day. There remain some model
differences in timing/position of these shortwaves but with the
proximity of front and track of shortwaves generally near the
southern portion of forecast area along with PWs near 2 inches expect
the southeast half of Upper Mi to have greatest chance of getting
rainfall and perhaps a potential of some heavier rainfall given high
PWs. Some of model guidance seems to suggest that the northwest half
of the cwa could see little to no pcpn Wed-Wed evening farther away
from frontal boundary and better shortwave dynamics and more
influenced by anticyclonic NE flow around sfc high over Northern
Ontario.
Models consistent showing a stronger shortwave from the Northern
Plains poised to move across the Upper Great Lakes late Wed night
into Thu. DPVA...upper diffluence and waa/isentropic ascent ahead of
the shortwave along with PWs aoa 1.5 inches will favor the northern
tier counties and particularly the nw portion of the cwa for the best
chc of rainfall Wed night into Thu morning.
Broad mid-upper level ridging and assoc Q-vector divergence/
subsidence in the wake of the shortwave Thu afternoon will allow for
a period of mostly dry weather Thu afternoon into Friday morning.
00z models trending much stronger with next shortwave approaching
from the Northern Plains in a zonal flow aloft for late Fri into Sat.
Deep layer q-vector convergence will bring another round of
showers/sct TS to the area late Friday into Saturday. Northwest winds
could get gusty on Sat with tightening gradient behind deepening sfc
low fcst to lift ne of Lake Superior Sat afternoon/evening. Model
soundings would suggest the potential for northwest wind gusts to 30
mph over the northern tier counties of the cwa and gusts to 40 mph
may even be possible over the tip of the Keweenaw and for shoreline
areas from Munising eastward. Would not be shocked to see a period of
gales over the eastern half of Lake Superior Sat afternoon into Sat
evening.
Ridging and subsidence behind Saturday`s shortwave and
assoc cold frontal passage should result in drier/cooler weather
later Sat night into Sun night. There is plenty of model uncertainty
with timing of next shortwave due to move in for early next week so
will continue to utilize model consensus pops next Mon into Tue.
Temps should remain near or slightly above normal from Wed through
Fri but then fall slightly below normal for the weekend in the wake
of the cold fropa Fri night. Dewpoints in the mid to upper 60s into
will make it feel quite humid into Thu, but then dewpoints should
fall back into a more comfortable 50s range for Fri into early next
week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 739 AM EDT TUE SEP 6 2016
As a steady SW flow advects very moist air into the Upper Great Lakes,
along with a few disturbances, expect clusters of showers and TS moving
thru the area. This will keep mainly mvfr or near mvfr conditions at
IWD and SAW. Abundant moisture from earlier rain along with upslope
flow that has produced fog and vsby blo aiport minimums, will give way
to improvment as winds veer and additional rain helps to scour out the
fog. Winds becoming nrly behind the front tonight will favor additional
fog development tonight with IFR possibly down to VLIFR conditions
late.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 517 AM EDT TUE SEP 6 2016
Winds through Fri night are expected to remain mainly at 20 kts or
less. The strongest winds will be Saturday with gusts up to 30 knots
out of the north and northwest as a deepening low pressure system
lifts to the e of Lake Superior. No gales are expected but cannot
rule out gale potential Saturday if the low pressure continues to
trend stronger.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Voss
AVIATION...JLB
MARINE...JLB
Area Forecast Discussion
National Weather Service Pueblo CO
446 AM MDT TUE SEP 6 2016
.SHORT TERM...(Today and tonight)
Issued at 446 AM MDT Tue Sep 6 2016
Moisture will continue to increase across southeast CO today as
tropical moisture gets caught up in southwesterly flow across
eastern AZ and NM and swept northeastward ahead of the western U.S.
upper trof. At the same time...upper trof out west will gradually
shift eastward putting increasing lift across CO during the late
afternoon and evening hours. Still a fairly dry airmass across
western sections of the area today where breezy southwest winds will
increase once more. There will be some marginal increase in
mid/high level moisture as the upper trof axis approaches. With
best moisture across the plains...along/east of a dry line across
the eastern counties...and along/north of a front in the proximity
of the Palmer Divide during the afternoon...these areas will stand
the best chance for thunderstorms this afternoon through evening. In
fact...latest sfc analysis shows front already approaching the
Palmer Divide this morning with stratus filling in across northeast
CO. Models mix this back northward during the afternoon...though
suspect GFS is a bit too aggressive with this idea and have leaned
grids towards the NAM12 and HRRR solutions. Greatest CAPE this
afternoon will once again be along/east of a dry line extending from
a line from roughly Kim to Las Animas to Eads where values of around
2000 J/kg will be in place. Another axis of higher CAPE (around 1000-
1500 J/kg) will be in the vicinity of the Palmer Divide this
afternoon. Deep layer shears will range from 20 kts across southern
sections to 40 kts across the north...so best severe thunderstorm
chances will be along/north of the front. Current SWODY1 carries a
marginal risk for severe across northern and eastern sections of the
plains...and in spite of marginal shear values across southeast
sections...copious amounts of CAPE may make up for this to some
degree. Damaging winds and hail to around 1 inch in diameter will
be the primary storm threats. This threat will increase into the
evening...particularly for northern sections of the southeast
plains as the front sags southward.
High res models move activity eastward through 06z with most
activity ending by early morning across far eastern sections. Front
makes another push into southeast CO tonight bringing the potential
for stratus and fog to develop across northern El Paso county
towards 06z. -KT
.LONG TERM...(Wednesday through Monday)
Issued at 446 AM MDT Tue Sep 6 2016
Relatively tranquil meteorological conditions are anticipated
during the longer term with primary meteorological issues being
temperatures in combination with gusty winds and generally low-
grade pops at times.
Recent longer range computer simulations...PV analysis and forecast
model soundings suggest that basically zonal to northwesterly upper
flow will prevail over the forecast district into early next
week...with primary deeper moisture from the remnants of Newton
expected to remain south of the forecast district. In
addition...north to northeasterly surface surges are anticipated
Wednesday night and Friday and then again by next Monday.
For sensible weather, will depict primarily isolated to scattered
showers and thunderstorms at times...especially by next week.
Also, the highest potential of gusty gradient winds should be
noted from later Saturday into Sunday.
Overall, maximum and minimum temperatures should run near and/or
above early to mid September climatological averages during the
longer term with warmest temperatures anticipated Wednesday,
Thursday and Sunday, while coolest conditions should be
experienced Saturday and then again by early next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 446 AM MDT Tue Sep 6 2016
VFR conditions expected at the terminals through the next 24 hours.
A slightly better chance for thunderstorms exists
today...particularly across El Paso county and eastern sections of
the southeast plains. Will carry VCTS at KCOS this afternoon and
evening with VFR CIGS possible. Erratic gusty winds will be the
primary threat...though as front shifts winds out of the north this
evening...this will bring a slightly better chance for thunderstorms
carrying VFR cigs/and potentially brief MVFR VIS with -TSRA.
Thunderstorms should pull east of the area after 06z with generally
VFR conditions returning. IFR CIGS will spread into northern El
Paso county late tonight behind the front but is expected to stay
north and east of the KCOS and KPUB terminals for now. Breezy
southwest winds 15-25 kts will spread into the KALS terminal this
afternoon...while KPUB and KCOS see more south to southeast winds in
the 10-20 KT range before winds shift out of the north this evening
as the front moves through. -KT
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
Area Forecast Discussion
National Weather Service Tucson AZ
442 AM MST TUE SEP 6 2016
.SYNOPSIS...Abundant moisture associated with Hurricane Newton will
bring periods of showers and thunderstorms this afternoon into
Wednesday evening. Locally heavy rainfall, flash flooding and strong
gusty winds at times will likely occur. A drying trend will begin
Thursday and continue into this weekend. However, lingering moisture
will maintain a few thunderstorms Thursday into this weekend.
&&
.DISCUSSION...IR satellite imagery and surface observations depicted
clear skies west of Tucson, and partly cloudy to cloudy skies from
the Tucson metro area eastward to the New Mexico border early this
morning. The present cloudiness moving northeastward mainly across
eastern locales is associated with a mesoscale convective system
that has mostly dissipated southeast of the area across northeastern
Sonora Mexico. A fairly dry surface regime still prevails early this
morning, with dewpoints at lower elevations valid 4 AM MST ranging
from the lower 30s northwest of Tucson, and into the upper 40s south-
to-southeast of Tucson. These temps were mostly 5-15 degs higher
versus 24 hours ago.
Meanwhile, the center of the large eye of Hurricane Newton was near
Cabo San Lucas, Mexico as per the latest Hurricane Advisory (Number
7) via the National Hurricane Center. Newton was moving toward the
north-northwest near 17 mph, and this general motion is expected to
continue through this morning. Newton is forecast to continue moving
over the southern portion of the Baja California peninsula through
this morning and afternoon, and move into northwestern Mexico early
Wednesday morning.
Regarding this forecast issuance, some fairly substantial
adjustments were made to the PoPs and QPFs for this forecast area,
especially for late tonight and Wednesday. These upward adjustments
were done based on the strength of Newton, which is a more potent
storm versus forecasts from 24 hours or longer ago. Please refer to
the latest Hurricane Newton Discussion (Number 7) that provides more
detailed information regarding the strength of this system, as well
as information regarding the GFS/ECMWF handling of this system.
Various 06/00Z Hi-res and global scale NWP guidance has also
suggested that rainfall will begin in this forecast area somewhat
earlier versus progs from 24 hours or longer ago.
As far as the forecast detail for southeast Arizona...
Have maintained precip-free conditions thru about 15Z-16Z today,
then showers/tstms should develop no later than early this afternoon
mainly south of Tucson. Showers and thunderstorms should then
increase in coverage the rest of this afternoon while moving and/or
developing generally northward or northwestward across the area. A
couple of the latest HRRR solutions suggest that some blowing dust
may be generated from these showers/tstms from near Tucson westward
and northwestward into the Tohono O`odham Nation and south-central
Pinal Co. Thus, have maintained patchy blowing dust in these locales
for late this afternoon and early this evening.
Based on various NWP guidance as well as coordination with WFO PSR
and the Weather Prediction Center, a Flash Flood Watch was issued
for all of southeast Arizona except Zone 501/Western Pima County
from late this afternoon through Wednesday evening. Given the
expected substantial moisture increase across the area later today
and into tonight, the belief is that conditions will become
increasingly favorable for flash flooding to occur.
The bulk of the heaviest and most widespread rainfall appears to now
be from late tonight into Wednesday afternoon or early Wednesday
evening. PoPs were adjusted upward to around 100 percent Wednesday
afternoon in north-south corridor from southeast Pinal County
southward across the Tucson metro area, and further south into Santa
Cruz County. However, PoPs are still fairly high elsewhere for
Wednesday afternoon. This period appears to be the time when the
remnant circulation moves northeastward across the area.
Another substantial increase to this forecast versus 24 hours or
longer ago was made to wind speeds, particularly for Wednesday. The
06/06Z MAV/MET MOS guidance for KTUS has sustained wind speeds of 20-
37 kts late Wednesday morning into Wednesday afternoon. KTUS has the
highest projected wind speeds versus KSAD/KOLS/KDUG, but gusty winds
should occur at those locales as well. Some gusty winds may linger
into Wednesday evening followed by markedly less wind late Wed night
into Thursday morning. The bulk of any heavy rainfall capable of
producing widespread flash flooding should end Wednesday evening as
the remnant circulation moves northeast of the area.
The so-called "storm total rainfall" or "event total rainfall"
amounts have been revised upward as well. Thus, the present
expectation is for 1-3 inches of rain across the valleys, and
locally heavier amounts in excess of 4 inches quite possible. The
favored "locally heavier amounts" loosely translates into mainly
near the mountains. Far western Pima County should have amounts
of mostly less than one inch.
By Thursday morning, the 06/00Z GFS/ECMWF/CMC were quite similar
with depicting nearly precip-free conditions across the area.
Moisture should be sufficient to isolated to scattered showers/tstms
Thursday afternoon, then mostly dry conditions across the area
Thursday evening into Friday night. Thereafter, GFS/ECMWF depict
high pressure aloft to expand over the southwestern CONUS this
weekend. These solutions as well as the official forecast depict
isolated to scattered showers/tstms to prevail this weekend.
High temps this afternoon should be about 10-15 degs cooler versus
Monday followed by even cooler temps Wednesday. A warming trend will
then prevail Thur-Sat, then high temps will remain closer to
seasonal normals Sun-Mon.
&&
.AVIATION...Valid thru 08/12Z.
Increasing moisture from the south will bring a steady increase in
mid and high clouds today with a chance of thunderstorms late this
morning through tonight. Local heavy rains and MVFR CIGS/VSBY with
strong storms. SFC winds generally southerly 8-15 kts. Beyond
07/12Z, the remains of Hurricane Newton will pass north across the
area Wednesday with heavy rains and potential for a period of strong
winds primarily affecting the KOLS, KALK and KTUS terminals.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Increasing moisture ahead of Hurricane Newton will
bring a few thunderstorms to the area this afternoon and evening
then periods of rain late tonight well into Wednesday night with
flooding rains possible. At this time it looks like zone 151 will
have the greatest impacts with storm total rains of 1-3 inches
possible in the valleys and in excess of 4 inches in the mountains,
especially the Santa Ritas. Strong winds could also be an issue as
the system moves north across the area during the day Wednesday.
Lingering moisture will result in a slight chance of showers and
thunderstorms Friday into Sunday.
&&
.CLIMATE...The lowest maximum daytime temperature on record for
Tucson International Airport on Wednesday, September 7, is 77
degrees set in 1919. The maximum recorded rainfall for Tucson
International Airport on Wednesday, September 7, is 1.15 inches set
in 2006.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from this afternoon through Wednesday evening
for Azz501>515.
&&
$$
DISCUSSION...Francis
AVIATION/FIRE WEATHER...Cerniglia
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service La Crosse WI
325 PM CDT TUE SEP 6 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 325 PM CDT Tue Sep 6 2016
The forecast that is most tangible is the next hours and into the
overnight. The greatest potential for flooding and heavy rain has
shifted south into northeast IA, MN-IA border, and
southwest/west-central WI. This is along the outflow boundary
from earlier storms that now lies along a KMCW-KDLL line.
The air mass over IA, south of the outflow boundary, is very ripe
with instability on the order of 3000 j/kg MU/SB CAPE. 19z surface
convergence has increased in nern IA over the past hour, and this
trend should continue. Low-level moisture transport at 850 mb
will increase in the 21Z to 02Z time frame, convergent right into
northeast IA and southwest WI. Air mass is going to be a near
record early September airmass for the Upper Miss Valley: 4.5-5km
warm cloud depth and just under 2" precipitable water. The rain
axis will probably be located very close to that boundary and near
the IA/MN border into central WI, just south of I-90. This air
mass could very easily produce 4-5" in 2-3 hours, with training
echo areas seeing higher than that. This could produce major
flooding if it sets up right. The guidance is pretty close to
consensus /CAMS included/ on this axis area. One possible saving
grace appears to be a faster veer to the low-level moisture
transport seen in the RAP/NAM runs, shifting the convergent nose
east after midnight. We shall see.
Our customers and partners should prepare for potentially
damaging flooding. Nighttime always makes me uncomfortable as
people drive into water without knowing.
Have updated our messaging through the day to focus on that
region a bit more south for flooding, damaging wind, and an
isolated tornado. At 19Z...mesoanalysis of the environment showed
the boundary was weakly capped but the shear environment
supported entry-level supercell tornadoes. We are preparing to
monitor storms very closely on that boundary when they initiate.
Further north the environment is a bit more muddled and while deep
shear is there...it appears bowing segments are preferred in the
more limited CAPE environment. So, away from the boundary,
damaging wind would be a threat through early evening.
Wednesday...Tough, as so much has to happen tonight that will
affect the forecast for Wednesday. After an active overnight
across southwest WI and northeast IA, there is suggestion that
this same area could be impacted by more heavy rain with shortwave
trough support Wednesday. The latest extension hours of the 06.19Z
RAP suggest the low-level moisture convergence will shift
southeast of the area Wednesday morning with a westerly low-level wind.
The 06.18Z nam is not so rapid to scour it east and looks to
develop convergence into southwest WI again in the morning,
intensifying it during the day into sw WI. The same heavy rain air
mass is in place, but the CAPE may be much less. Experience tells
me the rain will likely push the entire mesoscale southeast toward
Highway 20, reducing the heavy rain threat Wednesday. However,
confidence is not high enough yet to back out of forecast, but it
is something to consider.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 325 PM CDT Tue Sep 6 2016
The front becomes progressive and finally scours the soaker air
mass to our southeast by Thursday morning for a cooler less humid
day. It quickly rebounds Thursday night and Friday ahead of a
strong trough for renewed rain chances.
Friday night through Tuesday
Strong upper-level shortwave trough is forecast to move through the
Upper Midwest Friday into Saturday. Models are in much better
agreement than recent days with a broad surface low developing ahead
of the shortwave. 06.12z GFS and 06.00 ECMWF both bring strong low
to mid-level frontogenetical forcing across our area Friday night
into Saturday, providing a good chance of widespread rain showers.
CAPE appears to limited after sunset Friday evening. Saturday should
be cool and breezy, with a few light rain showers possibly lingering
across central Wisconsin as the upper-level shortwave and attendant
surface low depart the region to the east. Models continue to show
ridging through the region on Sunday ahead of a developing upper-
level longwave trough extending from Hudson Bay to the Pacific
Northwest. Both the GFS and ECMWF develop a cold front and bring it
through the Upper Midwest Monday into Tuesday, but the GFS is much
more progressive with this feature. At least scattered showers
and perhaps a few thunderstorms will be possible along and ahead
of the front, so will maintain low PoPs Monday and Tuesday for
now.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1247 PM CDT Tue Sep 6 2016
The showers and thunderstorms will move back into the TAF sites
between 06.21Z AND 06.23Z...and then continue through the night.
These showers and storms will likely lower visibilities and
ceilings into the IFR/MVFR range at times. This will be especially
the case from late this afternoon into the evening. In addition to
this, there will be the threat for severe storms during this time
frame. The main threats will be damaging winds and maybe an
isolated tornado.
During the overnight and Wednesday morning, ceilings and
visibilities along and north of Interstate 90 will likely remain
IFR/MVFR.
&&
.HYDROLOGY...
Issued at 325 PM CDT Tue Sep 6 2016
Biggest concerns are over the very heavy rain air mass over the
area through Wednesday night. Flood Watch was expanded to cover
the entire forecast area. Main axis of heavy rain should
be on KMCW-KDLL region. This may hit northeast IA again and the
terrain area of sern MN, western WI.
Rivers will all be on the rise into the later week.
Believe we will be able to cancel the Flood Watch in the
northwest after the threat diminishes overnight.
&&
.ARX Watches/Warnings/Advisories...
WI...Flood Watch through late Wednesday night for WIZ054-055-061.
Flood Watch through late Wednesday night for WIZ017-029-032>034-
041>044-053.
MN...Flood Watch through late Wednesday night for MNZ079-086>088-
094>096.
IA...Flood Watch through late Wednesday night for IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT/HOLLAN
AVIATION...BOYNE
HYDROLOGY...BAUMGARDT
Area Forecast Discussion
National Weather Service Cleveland OH
335 PM EDT TUE SEP 6 2016
.SYNOPSIS...
A ridge of high pressure will remain over the region tonight. The
high will weaken by Wednesday which will allow waves of low
pressure to move across the Central Great Lakes Thursday into the
weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Plenty of convective cu across the area today with dewpoints now
into the upper 60s and lower 70s. Radar shows isolated showers in
our area but more so just to our west. Movement is to the east so
would expect these showers to drift into the western counties late
afternoon/early evening. The HRRR also shows additions showers
popping up up central and east so for the evening will leave a
slight chance pop in place. Overnight there will be activity well
to our northwest and this should drift our way but do not expect
it to reach the area. Expect a muggy night with lows around 70.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
Wednesday the surface high will begin to weaken and the upper
heights begin to drop as well. Guidance is conflicted with the
MAV dry and the MET showing a chance or slight chance pop. Given
all that and the fact that capes are forecast to be 2500-3000j/kg
in the afternoon with very little CIN will bring in a chance pop
for the afternoon. Thursday morning thunder chances increase as
the high weakens further...low pressure moves through the central
lakes and a cold front sags toward the area from the north. Will
have low chance or slight chance in the morning but will move up
to high chance for the afternoon. Thursday evening will continue
chance pops...highest east...through the evening drying from the
west after midnight as drier air and high pressure briefly build
in. The front returns as a warm front Friday so will bring pops
back from the southwest during the day. Highs Wednesday upper 80s
to lower 90s...Thursday mid and upper 80s and Friday lower 80s.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
A more zonal pattern with somewhat cooler conditions is expected
during this period. A short wave with associated cold front is
expected to cross the region Saturday with fairly good timing
agreement between the GFS and ECMWF. Scattered to numerous showers
and thunderstorms can be expected with this front. High pressure
will build into the region Sunday and shift to the east on Monday.
850 mb temperatures cool down to 8-10C or slightly below normal.
This should produce surface temperatures slightly below normal too.
The zonal flow will continue into Tuesday with the approach of a
significant short wave across the upper Mississippi Valley. The
exact timing is in question with the ECMWF about a day slower in the
progression of the short wave and associated cold front across the
area Tuesday or Wednesday. It will be rather warm again ahead of the
front but strong cold advection can be expected after frontal
passage and the first feel of autumn.
&&
.AVIATION /18Z Tuesday THROUGH Sunday/...
A weak trough/humidity boundary triggered a few showers this
morning at the leading edge of a very warm and increasingly humid
air mass that is now spreading across the region. Generally VFR
conditions are expected into Wednesday with southwest winds of
8-12 knots with unrestricted vsby. Convective debris from
convection originating farther west may produce a sprinkle or
light shower over nw Ohio but timing and confidence is too low to
include in tafs for KTOL or KFDY. Will not mention any fog or haze
overnight given the recent dry spell which has dried out the
ground. The higher dewpoints and light sw flow tonight will
inhibit much radiational cooling. Expect fair weather cumulus to
dissipate before sun set and leave just scattered cirrus.
OUTLOOK...Periodic non-VFR possible Thursday through Saturday.
&&
.MARINE...
Tranquil conditions will prevail on Lake Erie into Wednesday with
high pressure located over the Tennessee Valley. We can expect
southwest winds of 5-15 knots. Winds will increase Thursday to
15-20 knots as a cold front approaches and crosses the lake
Thursday night. The front will return north as warm front Friday
night and another cold front will cross the lake Saturday night.
SCA conditions could develop Thursday evening and Saturday night.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...LaPlante
AVIATION...LaPlante
MARINE...LaPlante
Area Forecast Discussion
National Weather Service State College PA
604 PM EDT TUE SEP 6 2016
.SYNOPSIS...
A blocking ridge aloft over the region...and post tropical storm
Hermine east of the New Jersey Coast will keep central
Pennsylvania mainly dry and unseasonably warm, with slowly
increasing humidity as the week progresses. Isolated showers or
thunderstorms will become possible starting Wednesday...
especially across the western half of the state.
A cold front should pass through this weekend leading to a day or
two of seasonable temperatures before another warm-up occurs.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Flat cu were speckled about the mid afternoon sky as a
shallow/elevated layer of moisture streamed east into the region.
The moisture becomes deep enough to support more significant
convection across far swrn PA and eastern Ohio.
This warmer and more humid airmass will drift into the western
mountains of our CWA later tonight and Wednesday.
The past few runs of the HRRR are hinting at some isolated-sctd
showers moving into the region near and to the west of route 219
after midnight tonight. Precip amounts will be light and mainly
less than 0.10 of an inch.
Some patchy light valley fog will occur across central and nrn PA
late tonight/early Wednesday with temps dipping into the u50s and
l60s.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
PWATS increase and muggy works its way into the forecast again
for the mid to late week period as sfc dewpoints climb back to
near 70F over the entire area on Wed. Wed night will again be
humid.
Post TS Hermine should stay close enough east of the NJ coast to
create a north/south ribbon of subsidence/drying across the
Susq Valley and points east through the midday hours. Later Wed
afternoon and evening...the remnants of Hermine begin to
accelerate to the NE allowing deeper moisture to flood east across
Central and Ern PA.
Spread the chc for isolated-sctd showers east across the Central
Mtns and Susq Valley Wed afternoon...coinciding with the leading
edge of the muggy...2 inch PWAT air.
Pockets of sfc-based cape will climb to 2000-2500 j/kg...capable
of producing a few pulse tstorms after 17z.
Max temps Wednesday will once again be in the low-mid 80s across
the mtns...and upper 80s to around 90F elsewhere.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Hermine will meander over the Gulf Stream for the next couple of
days with the latest 12Z guidance agreeing that it will likely
take until late Thursday or early Friday before it finally begins
moving up off the Cape Cod coastal waters.
Upper ridging extending northward from the Gulf of Mexico will
keep the weather dry and warm to hot though at least midweek.
Active northern branch of the jet stream is forecast to send
multiple shortwaves eastward across the northern tier of the
conus...bringing an increase in the chances for
showers/thunderstorms for late in the week.
A stronger mid level trof/surface cold front is advertised for
later Saturday with Sunday bringing the hiest chances of pcpn
during the period. Behind the front, it will turning slightly
cooler and noticeably drier into early next week.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
High pressure should ensure VFR conds over most of central Pa
through Wednesday. The exception will be across the
western/central Mtns, where some early morning fog/low cigs
appear possible. Model soundings suggest 08Z-14Z is the most
likely time frame for reductions and KBFD appears most likely to
experience IFR reductions.
Although widespread VFR conds are expected Wed afternoon, sct tsra
could result in a brief vis reduction in a few spots.
Outlook...
Thu...Patchy AM fog possible. Isold PM tsra impacts possible.
Fri...AM low cigs possible w mtns.
Sat...Isold PM tsra impacts possible.
Sat evening/Early Sunday...A few showers/Tsra likely...especially
over NW PA as a cold front slides east across the region.
&&
.CLIMATE...
Interesting to note that MDT and IPT were both shy of their
record highs by just 4F on Monday. Records today: IPT=94 and
MDT=96.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...La Corte/Gartner
AVIATION...Fitzgerald/Lambert
CLIMATE...
Area Forecast Discussion
National Weather Service Cheyenne WY
211 PM MDT TUE SEP 6 2016
.SHORT TERM...(This evening through Thursday night)
Issued at 140 PM MDT Tue Sep 6 2016
Early afternoon water vapor loop showed a high amplitude ridge
over the southeastern CONUS and trough over the western CONUS.
Increasing southwesterly flow aloft prevailed over the Rockies
and plains. Surface front remains stalled from the Upper Midwest
through the central Great Plains and Rockies. Moist east-southeast
flow exists along and east of the Laramie Range with good low/mid
level wind shear and SBCAPES approaching 500 j/kg. The 18Z HRRR
develops a small complex of thunderstorms over Platte County after
20Z, tracking east across Goshen County through 00Z. CYS radar
detected a small thunderstorm southwest of Douglas. Will continue
to monitor radar trends through the late afternoon for additional
development with a marginal/isolated severe threat along the I-25
corridor and far southwest Nebraska Panhandle.
Scattered showers/thunderstorms will continue this evening along
and east of the Laramie Range, with convection ending after
midnight over the southern Nebraska Panhandle. The concern then
shifts to fog/low cloud development across the plains overnight
and early Wednesday morning. Winds veer around to southwest across
southeast Wyoming with drier low levels precluding fog formation.
Wednesday will be warmer with gusty westerly winds throughout the
day. Highs will range from the low 70s to low 80s. Thursday will
be a few degrees warmer but windier along and west of the Laramie
Range.
.LONG TERM...(Friday through Tuesday)
Issued at 140 PM MDT Tue Sep 6 2016
Friday...Progressive and sharp shortwave moving southeastward across
the Dakotas will send a dry cold front across our counties early in
the day, making for an autumnal feeling final day to the work week,
with high temperatures in the 60s to lower 70s.
Saturday...Another pleasant weekend on tap with northwest flow aloft
and a warming trend as heights and thicknesses rise. Maximum
temperatures just about perfect for this time of year for outdoor
activities. Continued dry with limited low and mid level moisture.
Sunday...Warming trend continues in the warm sector ahead of the
next potent cold front and shortwave. Maximum temperatures exceeding
80 degrees east of I-25 with dry airmass and downslope warming due
to west winds. Lack of low and mid level moisture precludes shower
and thunderstorm development.
Monday...Autumnal like feel again as a relatively strong cold front
passes early in the day, knocking high temperatures back into the
60s. The cold frontal passage itself will remain dry, however, moist
southwest flow aloft and localized upslope will aid in producing
scattered showers and thunderstorms in the afternoon, primarily
along and west of Interstate 25.
Tuesday...Shower and thunderstorm chances will gradually decrease
during the day as a ridge aloft develops and strengthens. Low level
southeast winds will keep cool upslope clouds and temperatures along
and east of I-25 with temperatures that may struggle to reach the 60s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1121 AM MDT Tue Sep 6 2016
Wyoming TAFS...VFR prevails, except at Cheyenne from 01Z to 06Z
when MVFR prevails.
Nebraska TAFS...Conditions improving to MVFR this afternoon, then
deteriorating to IFR again tonight from 04Z to 15Z, then VFR.
&&
.FIRE WEATHER...
Issued at 140 PM MDT Tue Sep 6 2016
Elevated fire weather conditions will continue this afternoon
along the Wyoming/Colorado border west of the Laramie range with
low humidities and gusty southwest winds. More widespread near
critical fire weather conditions will exist Wednesday afternoon
as low pressure tracks east across Montana during the day. A Fire
Weather Watch remains in effect for much of southeast Wyoming
with afternoon humidities falling to around 15 percent and west
winds gusting in excess of 25 mph. Stronger downslope winds and
lower humidities are forecast Thursday and critical fire weather
conditions could spread further east into the western Nebraska
Panhandle.
&&
.CYS Watches/Warnings/Advisories...
WY...Fire Weather Watch from Wednesday afternoon through Wednesday
evening for WYZ301-303-304-306-308-309.
NE...None.
&&
$$
SHORT TERM...MAJ
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...MAJ
Area Forecast Discussion
National Weather Service Des Moines IA
338 PM CDT Tue Sep 6 2016
.SHORT TERM.../Tonight/
Issued at 338 PM CDT Tue Sep 6 2016
Heavy rain threat, timing, and location were the main
concerns for this evening. Flash flooding seems feasible, especially
during the overnight hours along and north of Highway 20. Leaned
toward the latest couple runs of the HRRR as well as the 06.12z
ECMWF and even the 09.15z HopWRF have convection delayed until after
22z this afternoon. Thinking these have the best handle on
convective trends, but slightly too fast WRT initiation. Thus, cut
back on timing and nudged them further north late this afternoon
into the evening.
Water vapor portrays a nice atmospheric river into western to
northern Iowa and the GFS/NAM/ECMWF continue this trend throughout
the night. Frontal boundary extends from west-central Iowa north-
northeast through just south of Estherville into central Minnesota.
PWAT values range from 1.8-2.0 inches tonight into Wednesday morning
across northern Iowa which is about 200% above climatology for this
time of year. Strong moisture transport continues throughout night
and even increases with the LLJ increasing by around 03z Wednesday.
Warm layer cloud depths remain around 4000 meters with MCW BUFR
soundings suggesting fairly deep saturation across northern Iowa.
Surface dew points remain in the upper 60s to lower 70s overnight
with WAA persisting south of the frontal boundary. Decent moisture
convergence and enough forcing is likely late tonight and with the
above mentioned conditions, leaned toward a Flash Flood Watch along
and north of Highway 20. 3-hour Flash Flood Guidance is roughly just
over 2 inches in this area, and that could be realized over some of
the area tonight.
Confidence is low WRT to severe weather potential tonight as shear
remains unidirectional and the low level shear is fairly weak.
Certainly cannot rule out a brief incident of strong winds, but the
deep layer shear and instability looks too weak for any substantial
updraft to produce large hail. The main concern tonight is flash
flooding.
.LONG TERM.../Wednesday through Tuesday/
Issued at 338 PM CDT Tue Sep 6 2016
Thunderstorm chances will continue on Wednesday with the focus
area settling south into central Iowa. The biggest variable will
be overnight outflow boundaries and how far these may settle. Mid
level moisture transport (700-500 mb) streaming north from the
Pacific and low level moisture transport from the Gulf of Mexico
will converge over central Iowa by Wednesday morning and into the
afternoon. The deep moisture advection will push PWAT values up to
2.25 inches or nearly 250 percent of seasonal values. Storm
motions of 25 to 35 mph will allow storms enough residence time
for heavy rainfall due to expected high rainfall rates. In
addition, storm motions will become nearly parallel to the
boundary with the potential for training of storms. Current
headline likely will need to be shifted further south for
Wednesday but current headline will allow future updates based on
how the overnight convection evolves.
Severe weather will generally be low on Wednesday. Expect a mid to
high level cloud debris from overnight storms may linger over the
area much of Wednesday and limit the strength of instability and
reduce the severe weather threat. Saturating soundings will limit
the large hail threat thus the main threat for severe weather will
be damaging wind gusts.
Thunderstorm chances will linger over the southeast Wednesday
evening before drier air arrives leading to a dry Thursday.
Moisture advection will quickly move back north Thursday night
into Friday as the remnants of Hurricane Newton lifts into Kansas
and northern Missouri. As this occurs a strong short wave trough
will approach from the west bringing good forcing through the
region. Expect scattered elevated storms Thursday night followed
by surface based activity on Friday as the upper trough and
attendant surface boundary arrive. A few severe storms and locally
heavy rainfall will again be possible. Cooler and mostly dry this
weekend with the arrival of high pressure. Return flow develops
early next week as the high departs brining additional storm
chances.
&&
.AVIATION.../For the 18Z TAFS through 18Z Wednesday afternoon/
Issued at 1250 PM CDT Tue Sep 6 2016
Persistent MVFR ceilings look impact mainly FOD and possibly MCW
this afternoon into the evening. Anticipating convection to
initiate past 22z this afternoon and continue through much of the
evening. Have MVFR to IFR visibility tonight towards Wednesday
morning, more confident to keep these conditions going for an
extended time frame than sparse out a potential break. Additional
storms continue Wednesday morning, more likely further south
affecting DSM-ALO-OTM.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from 10 PM CDT this evening through Wednesday
evening for Black Hawk-Bremer-Butler-Cerro Gordo-Emmet-Franklin-
Grundy-Hamilton-Hancock-Hardin-Humboldt-Kossuth-Palo Alto-
Pocahontas-Webster-Winnebago-Worth-Wright.
&&
$$
SHORT TERM...Podrazik
LONG TERM...Donavon
AVIATION...Podrazik
Area Forecast Discussion...corrected typo
National Weather Service Detroit/Pontiac MI
306 PM EDT TUE SEP 6 2016
.DISCUSSION...
Hot and humid this afternoon as max temperatures reached around 90
degrees and dew pts reside in the low to mid 70s.
Upper level ridge in place (592 dam at 500 MB per 12z DTX raob) over
southeast Michigan will gradually weaken as multiple upper waves/pv
filaments stream out of the four corners region, allowing for
increasing chance of showers and thunderstorms over the next 48
hours as deep moisture plume and surface frontal boundary sags
south into southern Lower Michigan. Latest HRRR supports most of
the upstream activity dissipating as it encounters the ridge,
coupled with loss of daytime heating (which pushed MLcapes to 2000
J/kg per 18z spc mesoscale analysis). Isolated shower activity
noted this afternoon, roughly along and downwind of irish hills
where slightly better low level moisture resides. Unfavorable/general
subsidence underneath ridge axis, coupled with dry and warm mid
levels has and should continue to hold activity mostly in check.
Tomorrow remains challenging forecast as ridge still looks to be
holding up fairly well, as heights remain at or above 588 DAM, with
700 mb temps aoa 10 C. None-the-less, MLcapes on the order of 1000-
2000 J/kg with weakening to NIL Cap during the afternoon, and with
very moist airmass (PW values above 2 inches), will only takes a few
cells to get going with renewed activity on any outflow boundaries,
as highs are expected to be around 90 degrees again. With the
isolated activity generated this afternoon, felt compelled to
increase pops a little bit tomorrow (20 south to 55 near Saginaw
Bay), as there is surface trough/warm front noted in 12z euro
lifting through southeast michigan toward 00z Thursday. If night
shift has increased confidence in activity not materializing across
southern half of the cwa, may need heat advisory for Detroit Metro
Area as heat indices push toward 100 degrees once again.
Upper level trough axis over Pacific Northwest this afternoon will
move into the Upper Mississippi River Valley by Thursday morning,
helping to direct and capture an upper wave and associated tropical
moisture coming out of northern Mexico, with descent agreement
amongst Euro/Canadian/GFS/NAM, indicating a surface low tracking
through northern Lower Michigan or the Straights Wednesday
Evening/Night, driving cold front and tropical moisture (up to 8 c
dew pt at 700 mb) east through the cwa Thursday Morning, worthy of
high chance to likely pops. Jet forcing displaced to north is the
reason for more conservative pops farther south. If the front is a
bit slower and we get better surface heating on Thursday (forecasted
maxes currently low/mid 80s), severe storms will become concern as
0-6 KM Bulk shear ramps up through the day, exceeding 30 knots.
Surface high building in for Thursday night may set us up for fog as
enough surface/near surface moisture lingers and fails to mix out,
especially if we receive heavy rainfall Wednesday Night/Thursday.
Low pressure system moves up from the central plains Friday/Saturday
continuing chances for showers and thunderstorms for the first half
of the weekend. High pressure is expected for Sunday/Monday with
another weather system dropping out of the north toward mid-week.
High temps in the 70`s with lows in the 50`s through the period.
&&
.MARINE...
Prevailing southerly winds will remain modest in speed through
Wednesday as the region settles into a hot and humid stretch
downstream of a slowly approaching frontal boundary. Greatest
potential for thunderstorms through this time will exist along this
boundary stretching into central and northern sections of lake Huron.
Low pressure lifting along this boundary will bring an increasing
potential for thunderstorms all locations Wednesday night into early
Thursday. The passage of this low will prompt a brief increase in
southwest flow early Thursday, before diminishing as winds veer to
west and then northwest to finish the week.
&&
.PREV DISCUSSION...
Issued at 147 PM EDT Tue SEP 6 2016
AVIATION...
Expanding VFR diurnal cu field to blanket the region through the
evening period under hot and humid conditions. Little support to
suggest this environment will translate into shower/thunderstorm
development given the lack of forcing, but will continue to monitor
near term trends moving forward. There is a low probability that
ongoing convective activity upstream will funnel east rather than
hold to the northeast this evening/early tonight. This scenario
would introduce a chance of TSRA at mainly MBS during this time.
Otherwise, some degree of fog development likely given the uptick in
near surface moisture. Forecast still highlighting MVFR, but a
brief dip into IFR at one or more terminals certainly plausible.
For DTW...scattered to broken coverage of diurnal cu will settle
into the 5000 ft range through the afternoon. Mixed signal on how
quickly this cloud deck exits, will side with a gradual reduction in
coverage after 00z. Thunderstorm threat remains minimal through
early Wednesday.
//DTW Threshold Probabilities...
* Moderate for ceiling 5000 ft or less late afternoon into the
evening.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
DISCUSSION...SF/DE
MARINE.......MR
AVIATION.....MR
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Sioux Falls SD
321 PM CDT TUE SEP 6 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 319 PM CDT Tue Sep 6 2016
Tricky forecast in the short term with many different areas of
concern for the region. Current analysis shows a frontal boundary
set up across the southeast corner of the forecast area, roughly
from near Windom to Sioux City. Ahead of the front, dewpoints remain
in the lower 70s with temperatures creeping into the lower 80s. Most
models are having difficulty with the ongoing environment, however
the HRRR seems to have the best handle on the initial conditions and
precipitation trends. Instability is as high as 1500 j/kg in the
Storm Lake area, in a weakly capped environment. With bulk shear up
around 40 kt, think that severe weather will be possible in the
narrow corridor ahead of the front from around 5 pm to 9 pm this
evening.
Elsewhere, copious low stratus blankets the region near and west of
the boundary, and is even producing some patchy drizzle or
sprinkles. Think that precipitation chance this evening are fairly
low in the more stable environment. Expect isolated to scattered
showers with enough meager elevated instability to produce a few
lightning strikes through the evening.
Later tonight, the main upper level trough shifts into the northern
Rockies while a mid level shortwave lifts into the central and
northern high Plains. With stronger lift and support arriving after
midnight, showers and storms will again become likely, particularly
across far southeast SD, northwest IA and southwest MN late this
evening through the overnight hours. With the wave moving northeast,
scattered showers and storms remain in the picture through the day
on Wednesday, finally beginning to taper off in south central SD in
the afternoon. Severe threat looks very marginal for activity on
Wednesday. Shear is fairly high, but instability and meager lapse
rates may be more of a limiting factor. As it does not looks like
much of a break from the activity tonight into Wednesday, think that
clouds may limit the potential instability. Precipitable water
values remain somewhat high, but with the heaviest rainfall expected
southeast of where the recent heavy rainfalls occurred, do not think
there is enough of a threat of flash flooding for a watch at this
time.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 319 PM CDT Tue Sep 6 2016
High pressure will drift eastward into the CWA late Wednesday
afternoon, and should lead to fairly rapid downtrend in PoPs by the
evening. This break will be shortlived however as trends continue to
support increasing PoPs Thursday night into Friday as a rather
progressive upper wave pushes through the Northern Plains.
Instability is not that great, so severe weather risks are low. We
will be looking at scattered showers and occasional thunderstorms
into Friday afternoon.
Cooler Canadian high pressure will surge into the area late Friday
and race into the Ohio River Valley by Sunday. A pleasant and dry
weekend is anticipated. Temperatures will fall into the 40s to low
50s in many locations, with high temperatures in the lower 70s.
No strong push of return flow into next week, which should allow a
frontal boundary to move into the area on Monday with little
impact. A deeper surge of Pacific moisture arrives Monday night
and Tuesday, bringing an increased chance of rain to the forecast
in the outer periods of the forecast.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 103 PM CDT Tue Sep 6 2016
Wet weather pattern will leave low ceilings and occasional low
visibility in the picture throughout the TAF period. MVFR to IFR
ceilings blanket much of the area, however is expected to become
widespread overnight into late morning Wednesday. Showers with
embedded thunder will redevelop this evening and become more
widespread overnight. The exception will be across south central
SD where some higher ceilings and lower precipitation chances may
spread into the KHON area.
&&
.FSD Watches/Warnings/Advisories...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...
LONG TERM...Dux
AVIATION...
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
332 PM CDT TUE SEP 6 2016
.SHORT TERM...(This Evening through Wednesday)
Issued at 316 PM CDT TUE SEP 6 2016
Recent water vapor imagery showing southwest flow continuing
locally with upper wave rotating east into the Northern Rockies.
Some moisture aloft evident moving northeast across northwest Kansas
with diurnal cumulus field again developing in a moist atmosphere.
PW values were already near 1.8 inches per RAP analysis. Frontal
boundary was rather stationary from west central Kansas to northeast
Nebraska though little if any cumulus has formed there.
With little large scale forcing near it, the boundary looks to move
very little tonight into Wednesday afternoon. The main concern is
the increasing moisture through the column and any weak waves that
can move through the southwest flow to produce precipitation. The
models vary on this, but do steadily bring precip into the area
through the day Wednesday. Instability is rather limited with mid-
level lapse rates steadily decreasing with time. The warm and moist
atmosphere will keep some instability in place especially in the
daytime of Wednesday. With moderate winds aloft, enough shear will
be in place for at least minor concern for severe weather Wednesday
afternoon. Speeds aloft should be enough to keep precip moving, but
any activity able to train would present a heavy rain concern. At
this point, there aren`t any obvious training setups identified. In
the short term, will need to watch any activity to the west making
its way into north central Kansas this evening but this scenario
continues to be less likely in recent HRRR runs. In general have
slowed the onset of precip chances with time but most locations
should see decent chances for something by late Wednesday afternoon.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 316 PM CDT TUE SEP 6 2016
Wednesday Night through Saturday Morning...
For Wednesday night through Friday night, There is not much change
in the forecast thinking as models continue to show a moist and
modestly unstable airmass with deep layer shear on the order of 30
to 40 KT. By Friday evening, the cold front finally pushes through
the forecast area. So the period continues to look unsettled. The
biggest uncertainty is what forcing may impact the forecast area.
There is some spread in the models with the remnants of Newton
coming up from the southwest ranging from taking it to the south
across OK or bringing it across the forecast area. The NAM seems to
be the only solution taking the energy as far south as central OK.
Therefore think its solution is an outlier and prefer a blend of the
GFS/GEM/ECMWF. So there may be a subtle wave move across the area
Wednesday, remnants of Newton moving across the area Thursday, then
the front pushing through on Friday. The forecast has chance to
likely POPs through the period with them finally tapping off late
Friday night as the front starts to push out of the area. Increased
moisture and chances for precip argue for highs to be in the 80s.
This is supported by a gradual cooling in the 850MB temps and
lowering of 1000-500MB heights. Lows are forecast to remain mild
(lower 70s) Thursday and Friday morning as the cold air advection
holds off until Friday night.
Saturday Night through Tuesday...
A touch of "fall" will return for the upcoming weekend! Low
temperatures will dip into the low to middle 50s Saturday night.
High temperatures will remain comfortable in the upper 70s to near
80 Sunday afternoon! Thunderstorm chances return Monday afternoon
through Tuesday evening as a strong cold front pushes across the
area. Mid-level flow remains relatively weak with the frontal
passage, therefore do not expect severe weather. High temperatures
Tuesday afternoon are expected to be in the low 70s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1231 PM CDT TUE SEP 6 2016
VFR anticipated. Wind speeds not quite as strong as yesterday but
will again be gusty today. Conditions again set up for wind shear
from roughly 04Z-13Z. Precip chances do increase at the end of the
forecast but too little confidence for a mention yet.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...65
LONG TERM...Baerg/Wolters
AVIATION...65
Area Forecast Discussion
National Weather Service Tucson AZ
1015 AM MST TUE SEP 6 2016
.SYNOPSIS...A good chance of showers and thunderstorms today, then
abundant moisture associated with Hurricane Newton will bring
periods of showers and thunderstorms later tonight into Wednesday
evening. Locally heavy rainfall, flash flooding and strong gusty
winds at times will likely occur. Lingering moisture will maintain a
few thunderstorms Thursday into this weekend.
&&
.DISCUSSION...A strong moisture increase will see a marked increase
in thunderstorms this afternoon with strong outflows and possible
dust an issue. Brief heavy rain possible, especially in the
mountains. Focus for now is on areas near to south of Tucson. We
will probably see a break between this convection and the onset of
main influences from Newton.
As far as Newton, the table is set. Things have to happen just right
to have impact from a tropical system in southern Arizona, and all
analysis and model trends continue to point in the right direction.
The trough to our west and northwest is holding position just long
enough to finish guiding Newton into far northwest Sonora just south
of the border, and then looks like it gets out of the way to allow
Newton in instead of shearing the bulk of the remnants into New
Mexico.
One of the advantages that Newton has is it`s forward speed. There a
chance that he could reach the border as a minimal tropical storm
with sustained winds of 39 mph or a little higher. We are issuing a
wind advisory to address this issue, and will be watching trends to
make sure that will cover things.
The update also covered some timing issues, increasing the onset of
heavy precip by 3 or 4 hours with prime time looking like 06z to 21z
Wednesday for most of our area. QPF values are also increasing as we
gain higher confidence in the track. 1 to 3 inch rainfall amounts in
valleys with isolated amounts near 4 are possible. Some mountain
locations, especially closer to the border, could see up to 5
inches. The area that we are currently most concerned about is Santa
Cruz county, however it`s looking more and more likely that there
will be plenty of heavy rainfall potential for other areas as well.
The bottom line is Hurricane Newton is holding course and speed with
solid agreement between operational forecast models as well as most
tropical models. A quick look at 12z guidance including the UofA WRF-
NAM and latest HRRR is inspiring increasing confidence in
the forecast.
&&
.AVIATION...Valid thru 08/18Z.
Increasing moisture from the south will bring a steady increase in
mid and high clouds today with a chance of thunderstorms late this
morning through tonight. Local heavy rains and MVFR CIGS/VSBY with
strong storms. SFC winds generally southerly 8-15 kts. Beyond
07/12Z, the remains of Hurricane Newton will push north across the
area Wednesday with heavy rains and potential for a period of strong
winds primarily affecting the KOLS, KALK and KTUS terminals.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Increasing moisture ahead of Hurricane Newton will
bring a few thunderstorms to the area this afternoon and evening
then periods of rain late tonight well into Wednesday night with
flooding rains possible. At this time it looks like zone 151 will
have the greatest impacts with storm total rains of 1-3 inches
possible in the valleys and in excess of 4 inches in the mountains,
especially the Santa Ritas. Strong winds could also be an issue as
the system moves north across the area during the day Wednesday.
Lingering moisture will result in a slight chance of showers and
thunderstorms Friday into Sunday.
&&
.CLIMATE...The lowest maximum daytime temperature on record for
Tucson International Airport on Wednesday, September 7, is 77
degrees set in 1919. The maximum recorded rainfall for Tucson
International Airport on Wednesday, September 7, is 1.15 inches set
in 2006.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from this afternoon through Wednesday evening
for AZZ501>515.
Wind Advisory Wednesday for AZZ503-504-507-508-512>515.
&&
$$
Meyer/French/Leins
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