Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/17/16
Area Forecast Discussion
National Weather Service Dodge City KS
633 PM CDT FRI SEP 16 2016
...Updated for Aviation...
.SHORT TERM...(This evening through Saturday)
Issued at 211 PM CDT Fri Sep 16 2016
A stubborn corridor of low stratus has persisted along the surface
cold front boundary this morning into the mid afternoon. These
clouds should improve along the central corridor, as the frontal
boundary eventually shifts east later this afternoon and tonight
while redeveloping farther east when the BL cools. The HRRR is
still holding on to chances for convection along what appears to
be a SE advancing radar fineline late this afternoon. The window
for isolated storms is small however with the loss of differential
heating.
By Saturday, weak high pressure settle in behind the surface
boundary which should be over western OK. That will mean generally
light and variable winds in central KS with more of and easterly
component for much of our area, and slightly warmer temperatures
around 80 with more abundant insolation.
.LONG TERM...(Saturday night through Friday)
Issued at 211 PM CDT Fri Sep 16 2016
Models indicate a shortwave moving out of the Rockies into the
Plains by late Saturday. The recent WRF runs are perhaps the most
robust in terms of driving initial surface based colorado
convection into western and even central Kansas Saturday night. It
is likely the mid level instability will be more of a factor in
sustaining storms this far east, as the surface dew points in the
far west have decreased significantly. The rest of the extended
period will generally be dry as a zonal flow and high pressure pattern
takes shape for the central Plains. However the model blends
suggest a return of thunderstorm chances late in the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 629 PM CDT Fri Sep 16 2016
VFR conditions are forecast. As surface high pressure moves east,
light winds will gradually become southeasterly after 15-17Z. Some
mid level clouds increase also.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 55 81 59 88 / 10 0 30 10
GCK 53 81 57 88 / 0 10 30 0
EHA 55 81 58 88 / 0 30 30 0
LBL 56 81 59 89 / 0 20 40 10
HYS 55 81 58 87 / 0 0 20 0
P28 61 83 61 87 / 20 0 20 10
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Kruse
Area Forecast Discussion
National Weather Service Quad Cities IA IL
657 PM CDT FRI SEP 16 2016
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 307 PM CDT Fri Sep 16 2016
More breaks in the clouds helped early afternoon temperatures warm
up into the lower 80s over much of the area. Areas behind a cold
front, from Freeport to Iowa City and points to the northwest,
were generally in the 70s. A broken line of showers and isolated
thunderstorms continued to develop along the cold front, near and
just west of the Mississippi River.
&&
.SHORT TERM...(This Evening through Saturday)
ISSUED AT 307 PM CDT Fri Sep 16 2016
The main forecast issued in the short term period are timing and
coverage of showers/thunderstorms through tonight.
Latest runs of the HRRR continue to model the current convective
development near the Mississippi River quite well and gradually
translate the broken line of showers and thunderstorms to the
east of the river through the early evening. Some isolated small
hail and gusty winds not out of the question with the strongest
storms, but the threat for severe weather remains low, mainly due
to relatively weak instability and deep layer shear. A few
showers/isolated storms will be possible again later tonight, but
have followed the 12z model trends in trimming back pops. Again,
areas along and east of the Mississippi will be most favored for
rain. Lingering cloud cover will influence lows tonight, with the
northwest Wapsi Valley areas favored for the most clearing. These
areas will likely dip into the mid 50s.
On Saturday, drier air will filter into the region behind the cool
front. Expect near normal highs from the low to mid 70s north, to
near 80 degrees south.
.LONG TERM...(Saturday Night through Friday)
ISSUED AT 307 PM CDT Fri Sep 16 2016
A shift toward a more zonal upper level flow, with the main jet
stream setting up along the U.S./Canadian border, will return
summer-like weather for much of next week. This will lead to
above to well above normal temperatures and seasonably high
humidity levels. Weak frontal systems will bring potential for
showers and thunderstorms Monday into Monday night, with a more
likely setup for widespread rain late in the week.
Sunday into Sunday night, the high shifts eastward with a breezy
return flow warming temperatures into the upper 70s to lower 80s.
Subsidence aloft and dry air should lead to mostly clear skies, but
winds should stay up enough overnight to result in warmer night with
mins from the upper 50s to lower 60s.
Monday, a shortwave passing well to the north is shown drawing
deeper moisture northward into the area, likely sufficient to
support at least scattered showers and thunderstorms with the
associated cold front in the afternoon and evening. Current timing
would allow enhanced prefrontal warming to boost temperatures into
the lower to mid 80s. High pressure that follows should allow mins
to return to the 50s over much of the area.
Tuesday will be between systems with slightly cooler temperatures.
Convection is shown by the ECMWF and especially the GFS setting
along a moisture convergence axis across the far north and NW late
Tue night into Wed. The developing southerly winds will bring
humidity back into the area with highs from the upper 70s north to
possibly mid 80s in the south through Friday. Rain chances increase
Thu and Fri as a the upper flow becomes more active from the
southwest ahead of a developing trough over the Pacific NW.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
ISSUED AT 643 PM CDT Fri Sep 16 2016
Drier air working in behind a weak cold front will lead to mainly
dry conditions through this TAF period. The lone exception is KBRL
where light showers are possible this evening into early tonight
as moisture streams up from the SW. Light southwest winds
overnight should preclude dense fog formation, but will re-
evaluate in next TAF update. Uttech
&&
.HYDROLOGY...
Issued at 127 PM CDT Fri Sep 16 2016
Adjustments were made this morning based on new forecasts and
increasing confidence of flooding enhanced by the heavy rainfall
that occurred last night over the upper reaches of the Cedar, Iowa
and Wapsipinicon river basins.
Along the Wapsipinicon River at DeWitt: New forecasts over the past
couple runs have indicated a change from expected minor to now
moderate flooding. With flood stage now looking increasingly more
likely to be surpassed within 48 hours, have upgraded the watch to a
warning for moderate flooding.
Along the Iowa River: At Marengo, will be continuing the flood watch
and monitor trends closely this afternoon as sharp rises continue
there and at points upstream. If current trends continue, the watch
may be upgraded to a warning for minor flooding this afternoon or
this evening. Further downstream, adjusted forecasts taking into
account release forecasts from Coralville no longer indicate
flooding at Wapello or other sites downstream from Iowa City.
including Wapello.
Minor flooding that began last night along the Cedar River near
Conesville continues this afternoon and the flood warning remains in
effect.
&&
.DVN Watches/Warnings/Advisories...
IA...None.
IL...None.
MO...None.
&&
$$
SYNOPSIS...RP Kinney
SHORT TERM...RP Kinney
LONG TERM...Sheets
AVIATION...Uttech
HYDROLOGY...Sheets
Area Forecast Discussion
National Weather Service Grand Forks ND
955 PM CDT FRI SEP 16 2016
.UPDATE...
Issued at 955 PM CDT Fri Sep 16 2016
Upper level low was located over northwest MN. Upper low forecast to
open up. Water vapor loop indicated one short wave was rotating
around the upper low and was located over north central MN.
Precipitation was decreasing in area and intensity with loss of
heating and upper low moving out. Decreased pops with decreasing
precip for overnight. Clearing was beginning over the far northwest
zones. Decreased low temps for northwest zones tonight.
UPDATE Issued at 659 PM CDT Fri Sep 16 2016
Tweaked pops, wind, sky, and qpf for tonight. No other changes at
this update.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 257 PM CDT Fri Sep 16 2016
The main forecast challenge will be the potential for any strong
to severe thunderstorms across southeast ND into west central MN
into the early evening. On the positive side, the SPC meso page
shows sfc based lifted indices just slightly below zero across
most of the FA. Some holes in the clouds have allowed temps to
rise into the upper 60s across southeast ND and west central MN,
with dew points in the upper 50s. This has resulted in sfc based
CAPE values of 500-1000 J/kg. Water vapor imagery shows another
wave moving toward southeast ND, rotating around the parent upper
low over east central ND. It appears this area is being picked up
somewhat by the non supercell tornado parameter on the SPC meso
page, depicting a weak circle over southeast ND.
On the negative side, 0-6km shear is weak, with the higher values
moving into eastern MN. 0-3km VGP values around 0.1 are more over
southwest MN, water vapor shows a more disjointed low, and the sfc
pattern is weak. SPC maintains a marginal risk for severe weather
over west central MN through early evening. The Mayville radar has
shown an increase in popcorn showers and weak thunderstorms over
the past hour. The HRRR continues to show this activity spreading
into west central MN through the evening. So there is still a
window from late afternoon into early evening where a few strong
to severe storms are possible. Otherwise the pcpn will slowly
decrease from west to east tonight into early Saturday.
.LONG TERM...(Saturday night through Friday)
Issued at 257 PM CDT Fri Sep 16 2016
A pleasant Saturday should be followed by similar weather on Sunday.
Some cloud cover is likely to stroll from west to east along the
International border by afternoon, but surface low pressure should
remain far to the north over central Manitoba along with
accompanying forcing vis a vis 500 mb short wave. So slight pops are
featured only along far northern parts of the forecast area.
Elsewhere a southwest breeze will boost the mercury well up into the
70s. On Monday this system will head farther to the north and east
leaving the region with partly sunny skies and near seasonable
temperatures.
High pressure and zonal flow translates to another sunny and
seasonal day Tuesday but on Wednesday there is a risk of some
isentropically induced -RA/-SH north of a boundary lurking just
south of the forecast area. By Thursday a closed "bowling ball"
feature has a good shot of moving out of the northern high plains,
affecting our region with perhaps an extended period of pcpn later
Thursday on into Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 659 PM CDT Fri Sep 16 2016
Mostly MVFR cigs were located over the northwest third of the area
or roughly northwest of a line from JMS to south of GFK to west of
ROX. An isolated IFR cig was in the above area. VFR cigs were also
moving into the far northwest zones or north and west of Cavalier
ND. the south and east zones had VFR cigs. Satellite loop indicated
some holes over the south and east zones. Expect the MVFR band to
the north and west to shift south and east overnight. May see more
IFR cigs as the night progresses in this band. The MVFR band should
shift out of the area by Sat afternoon.
&&
.FGF Watches/Warnings/Advisories...
ND...None.
MN...None.
&&
$$
UPDATE...Hoppes
SHORT TERM...Godon
LONG TERM...WJB
AVIATION...Hoppes
Area Forecast Discussion
National Weather Service Grand Rapids MI
738 PM EDT FRI SEP 16 2016
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 328 PM EDT Fri Sep 16 2016
A frontal system moving through the area tonight through Saturday
will bring some periods of showers and isolated storms through
Saturday morning. Rain should diminish from Northwest to Southeast
Saturday afternoon. There will be a small chance of a light rain
shower Sunday afternoon as a weak wave of low pressure passes
through.
Drier weather will move back in across the area later on Sunday
along with seasonable temperatures.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 328 PM EDT Fri Sep 16 2016
Our main focus is on the pcpn and thunder chcs and trends through
Saturday afternoon.
We are watching two areas of showers and a few storms that are
poised to move through portions of the area through Saturday.
The first one is the line that is currently developing across
central and eastern Wisconsin this afternoon. This line is just
ahead of the cold front, and is moving into a ribbon of 1000+ j/kg
of sfc based CAPE. We expect this line to move in this evening and
tend to weaken some as it moves through the area with the loss of
diurnal heating. A few spotty showers could develop ahead of this
with increasing moisture transport taking place in the mid levels.
There may be a lull in the activity after the line this evening.
We expect then that the area of showers and storms across KS and
MO will make it`s way up toward the SE half of the CWFA late
tonight and Sat morning. This pcpn will be drawn north toward the
area as the RRQ of an upper jet develops and moves through the
region. We expect most of the storm activity to remain south of
the area with the srn portion of the llj staying south. There is
enough instability that thunder will remain possible, but not
likely.
The cold front should then move through on Saturday with little
fanfare. The atmosphere will not have much of a chance to
destabilize before the front pushes through during the afternoon
hours due to the lingering clouds and rain earlier. The majority
of pcpn should be S and E of the CWFA by late afternoon.
We have left the small chance of light rain showers in the fcst
for Sun afternoon. We will see one more short wave move through
during peak heating on Sun. There is not a lot of instability with
just a couple hundred J/kg of CAPE. There is enough for a few
showers though. These will end late Sun afternoon, leaving Sun
night to be dry.
.LONG TERM...(Monday through Friday)
Issued at 328 PM EDT Fri Sep 16 2016
Guidance has been trending faster with the cold front next Monday,
associated with the nrn stream shortwave racing across the Lake
Superior region. Pops for showers and tstms are now warranted for
Monday afternoon in western sections, and may need to be expanded
for the entire area in later forecasts if the faster trend
continues. The current timing supports best pops on Monday night,
followed by dry weather Tuesday and Tuesday night as high pressure
impacts the area.
Things could turn active for the mid to late portion of next week as
models show a quasi-stationary sfc frontal boundary possibly setting
up over srn lwr MI. However confidence is low regarding the daily
position of this front, and location of best PoPs/FGEN forcing,
especially since previous runs had the front much farther north next
Thursday and Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 732 PM EDT Fri Sep 16 2016
Scattered thunderstorms early this evening may produce brief
reductions of visibility to IFR but otherwise cigs and visibility
will generally hold up in VFR or MVFR with this activity.
Overnight, a gradual reduction in cigs is strongly indicated by
the RAP model RH at 975 mb. It seems by 04z-06z the cigs will
begin dropping and by 09z there may be widespread IFR with LIFR
possible especially at LAN and JXN. Rain along with a few
thunderstorms moves in during the early to mid morning hours which
will help the IFR linger well into the mid to late morning.
&&
.MARINE...
Issued at 328 PM EDT Fri Sep 16 2016
We will be leaving the Small Craft Advisory and Beach Hazards
statements in effect with this forecast package. Conditions have
been somewhat marginal thus far with a slightly offshore component
to the wind. This will becoming a little more favorable this
evening as winds are fcst to turn a little more SSW before winds
come down later this evening. Winds will not settle down entirely,
with winds up to around 20 knots at times through Sat night, and
then increase again Sun night after a brief break.
&&
.HYDROLOGY...
Issued at 1158 AM EDT Fri Sep 16 2016
Rivers are running near to slightly above normal, but are stable
and remain well within their banks. Moisture will stream northward
out of the gulf late today into early Saturday, lending itself to
developing showers and a few thunderstorms. Some of the rain may
be locally heavy. Aerial averages should result in around one-
quarter of an inch. Widely scattered storms are possible Saturday
with lingering shower possible Sunday. Little additional
precipitation is expected. There are no flooding concerns through
the next several days with little to no signal of any bigger rain
producers.
&&
.GRR Watches/Warnings/Advisories...
MI...Beach Hazards Statement until 5 AM EDT Saturday for MIZ037-043-
050.
LM...Small Craft Advisory until 5 AM EDT Saturday for LMZ847>849.
&&
$$
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...Meade
AVIATION...Hoving
HYDROLOGY...JAM
MARINE...NJJ
Area Forecast Discussion
National Weather Service Houston/Galveston TX
937 PM CDT Fri Sep 16 2016
.DISCUSSION...
The weak surface low indicated on the water vapor imagery and
also noted on METAR observations in the northwestern Gulf, is
continuing to drift to the north. This system is keeping higher
forecasted PoPs over the eastern offshore waters this evening and
into the early morning. An isolated shower or thunderstorm cannot
be ruled out along the coast, especially along the eastern half of
the CWA. The 00z CRP and LCH soundings are still showing
precipitable waters between 2.10 to 2.50 inches for tonight.
Dewpoints are remaining in the upper 70s slightly inland within
the coastal counties, but the best saturation still sits well to
the east outside of our forecast area where the weak low is
providing onshore flow.
Short term guidance from both the RAP and HRRR are keeping the
potential for a localized heavy downpour or isolated shower over the
northern counties, until about 09Z this evening. Precipitation would
be associated with a weak boundary that is currently sitting to the
northwest that is slowly pushing into our area. This feature could
help to provide some lift overnight as it moves to the southeast.
Outflow is currently helping to drive convection along the boundary.
If the outflow continues to develop as it moves into our northern
counties, could be the mechanism helping to produce some of these
isolated showers or thunderstorms. The boundary is currently along
the I-20 corridor west of Dallas. Forecast soundings are showing
decent saturation in the lower levels up to about 850mb, starting
at about 03Z this evening and until tomorrow morning.
Tweaked our temperatures for tonight a degree or two. After taking a
preliminary look at model guidance, it appears as though guidance is
looking to be slightly drier for the weekend. Wont make any
wholesale changes just yet, but rain chances may need to be lowered,
and temperatures may need to be raised a tad in the early morning
forecast package. These changes would be due to the dry air that
is filtering in ahead of the weak boundary moving in from the
northwest, as well as subsidence pushing in along the backside of
the low pressure system sitting off to our east.
Hathaway
&&
.PREV DISCUSSION... /ISSUED /
AVIATION...
The main aviation concerns for the 17/00Z TAFs center around SHRA
near the central terminals early this evening, MVFR ceilings and
visibilities developing early Saturday morning north of the
Houston terminals, and SHRA potential near the terminals on
Saturday.
A few SHRA continue to fire along remnant outflow boundaries
early this evening near CXO and east of IAH/HOU, but expect this
activity to dissipate by mid-evening with loss of daytime heating.
SHRA and TSRA associated with a weak surface low south of Cameron,
LA (CWV) are expected to continue to drift inland away from
Galveston this evening, allowing light easterly flow to become
light and variable to light and southeasterly by Saturday morning
with speeds 10 knots or less through the period. Latest HRRR
ceiling progs show some IFR to MVFR ceilings developing as
moisture wraps around the surface low as it moves inland tonight
and may see brief category restrictions at UTS/CXO (possibly as
far west as CLL) as a result. Similar to last night, patchy fog
development near CXO/UTS is also possible and have included MVFR
tempo groups as a result.
Weak coastal convergence as southeast winds across the Gulf
becomes established tonight should result in isolated SHRA
developing near GLS early Saturday morning, with additional SHRA
development spreading inland along a weak sea breeze late morning
to early afternoon. Subsidence in the wake of the departing
surface low/ parent upper level disturbance is expected to
relegate greatest SHRA coverage to the coastal TAF sites on
Saturday, but with convective temperatures near 90 for the Houston
terminals may see a few showers farther north (IAH/SGR/CXO) during
the afternoon.
Huffman
PREV DISCUSSION... /ISSUED /
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 76 92 76 92 75 / 20 30 10 20 10
Houston (IAH) 76 89 76 91 74 / 20 50 20 30 10
Galveston (GLS) 81 86 81 87 79 / 30 50 30 40 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...08
Area Forecast Discussion
National Weather Service Wichita KS
853 PM CDT FRI SEP 16 2016
.UPDATE...
Issued at 846 PM CDT Fri Sep 16 2016
Updated to clean up pops and to insert fog for south central and
southeast KS.
Showers have exited southeast KS and the storms west of
Kingman/Harper have dissipated. Additional showers/storms are not
expected overnight. Did go ahead and insert fog for areas
generally along and southeast of the KS Turnpike. This will mainly
be a radiational fog scenario as the low levels remain fairly
moist with clouds clearing.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 305 PM CDT Fri Sep 16 2016
Forecast challenge - Precipitation for this evening and tonight as
the cold front pushes southeast.
Convection that began off of an outflow boundary from the overnight
activity ahead of the front has persisted in south central and
southeast Kansas throughout the day. Given the worked over
environment following this convection, it is not likely that there
will be widespread redevelopment in most of south central as the
front moves southeast. However, there was brief scattered
development along the front in the early afternoon. In the clearing
across southwest Kansas, scattered clouds have started to bubble
along front which may move into south central Kansas. Right now
reservation exists on how the evening will evolve. The HRRR and
other models show persistent activity in southeast Kansas which will
diminish after 0z with a complete exit by ~3z. Given the radar, it
could be even sooner.
Current thinking is the activity that would develop would be
mainly heavy rain producers for the area which could lead to
flooding. Ongoing convection falling onto the moist surface from
the storms of last evening has caused flooding problems in
southeast Kansas. Obviously any additional rainfall would
exacerbate the problem. Chances of precip were held through the
evening and overnight for now, yet anticipation in changes of the
current forecast are likely.
A ridge moves in for Saturday which will bring a pleasant day across
the Plains. Outdoor activities are encouraged to flourish. There is
a weak wave that will push through on Saturday night into early
Sunday, but this is a very subtle feature especially closer to the
surface. It is not out of the realm of possibility for scattered
shower and thunderstorm activity after midnight along the KS/OK
border. Slight chances were removed for the evening as the slight
possibility appears to be later.
.LONG TERM...(Tuesday through Friday)
Issued at 305 PM CDT Fri Sep 16 2016
A ridge builds back in for the first of the week and will encompass
a majority of the CONUS. The next trough will come from the Pacific
Northwest on Wednesday. There is another subtle wave along the lee
of the Rockies ahead of the main trough which will meander east for
the latter part of the week. Models have definitely come into better
agreement than yesterday with only slight timing differences; the
Northern Plains anticipated position will cap off the work week.
Current indications suggest this trough will be deepen more than the
system from this week. More changes are on the way for the evolution
of this system through model land.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 633 PM CDT Fri Sep 16 2016
Aviation concerns will be fog and low clouds tonight into Sat
morning.
Front currently extends from southeast Nebraska to between KDDC
and KICT. While there isn`t much temp gradient with the front,
there is a sharp dewpoint gradient, with moist low levels
remaining over the eastern half of KS. Showers are departing se
KS with the storms west of Pratt and Harper not expected to affect
any of the tafs sites. With moist low levels remaining overnight,
main concern will be developing fog and/or low clouds for all
sites with the exception of KRSL-KGBD. At this time KICT and KCNU
look to have the highest probability of seeing fog, especially if
clouds clear out this evening. To gets things started will run
with 4-6sm and MVFR cigs. May hit harder if 00z models runs
continue to look favorable.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 62 82 63 85 / 10 10 10 10
Hutchinson 60 82 61 85 / 10 10 10 10
Newton 61 81 61 84 / 10 10 10 10
ElDorado 63 82 61 84 / 10 10 10 10
Winfield-KWLD 64 83 63 86 / 10 20 20 10
Russell 54 81 59 87 / 10 10 10 10
Great Bend 54 82 59 87 / 10 10 10 10
Salina 59 82 60 86 / 10 10 10 10
McPherson 59 81 60 85 / 10 10 10 10
Coffeyville 65 84 62 86 / 50 20 20 20
Chanute 64 82 61 84 / 60 20 10 10
Iola 64 82 61 83 / 60 20 10 10
Parsons-KPPF 64 83 62 85 / 50 20 10 20
&&
.ICT Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...RBL
SYNOPSIS...VJP
SHORT TERM...VJP
LONG TERM...VJP
AVIATION...RBL
Area Forecast Discussion
National Weather Service Lincoln IL
914 PM CDT FRI SEP 16 2016
.UPDATE...
Issued at 910 PM CDT Fri Sep 16 2016
An elongated shortwave extending from central Illinois back to
central Missouri will continue to create rain and isolated storms
for the rest of the night. Areas east of the Illinois river will
be the primary area affected by the wave, which looks to maintain
some influence east of I-57 even up through mid-day on Saturday.
Severe weather is not expected, but locally heavy rainfall could
produce some ponding of water in low spots and poor drainage
areas. Have updated PoPs and weather to cover the ongoing rains
and expected progression of steady rains. Temps will be held
warmer with persistent cloud cover and rains, along with mild
dewpoints in the upper 60s to low 70s. Low temps may reach as low
as the mid 60s NW of the IL river, with upper 60s E of I-57. Winds
will remain SW through the night under the influence of WAA flows
ahead of the upper trough in the Plains. Updated forecast info is
already available.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 259 PM CDT Fri Sep 16 2016
Several disturbances ahead of a cold frontal boundary currently
extending from Minnesota southward through Oklahoma will be the main
features over the upcoming day. Presently, a small break between
thunderstorm clusters over central and southeast IL looks on track
for portions of the afternoon...then a disturbance currently over
Missouri looks to spread additional thunderstorms into the area for
the evening. latest HRRR model appears best on track with these
features and have used this solution as a guide for tonight bringing
back likely thunderstorms from around I-72 southward through the I-
70 corridor by 6 p.m. and 30-50 percent chance to the north.
Scattered thunderstorms should persist through the night...then
shifting slowly eastward through the day Saturday while tapering off
from west to east. Lows tonight in the mid to upper 60s in the moist
air mass ahead of the approaching cold front...then highs around 80
again Saturday as temperature contrast across the frontal boundary
is minimal compared with the change in dewpoint...which should begin
to drop into the upper 50s behind the front.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 259 PM CDT Fri Sep 16 2016
The cold front should finally move through the rest of the state
Saturday evening. With both the GFS and NAM hinting at additional
precip developing along the front, keeping a chance of showers and
storms in the forecast for the east and southeast parts of the CWA
is a good forecast. Dry weather is then expected for the rest of the
weekend and into the beginning of next week. However, with a
somewhat zonal flow, another weather system will approach the area
but will have limited moisture. The strongest part of this next
system is expected to move into the Great Lakes region, but a
trailing cold front will drop through the area Monday night. Will
maintain a chance of showers and storms in the northern part of the
CWA, mainly north of I-72. Another weather system is possible in the
zonal flow for the last half of the week, but again, moisture will
be limited. Also, models differ on placement and timing of the
precip so will just keep the model blend of 20 pct chance of precip
for Wed night through Friday.
Zonal flow across the northern half of the US, from the weekend and
through next week, will be conducive for an upper level high
pressure to build into the southern US. This will bring warmer temps
back into the area through most of the period. Expect highs during
the afternoon above normal, in the lower to middle 80s; with above
normal lows as well.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 700 PM CDT Fri Sep 16 2016
An extended period of forcing for precip will be affecting our
forecast area overnight, as a 500 mb shortwave progresses NE
across IL. The result will be steady rains and isolated
thunderstorms at the terminal sites overnight. There may be
periods of MVFR cloud and vis conditions during any heavier rains
or storms. IFR conditions should be short-lived if they develop at
all.
It appears the back edge of the main wave of precip will reach
SPI late tonight into Sat morning. That trend should provide
decreasing rain and storm chances for at least the western
terminals of SPI and PIA in the morning. Continued rain chances
may linger through mid-day at BMI, DEC and CMI. VFR conditions and
some clearing is expected later Sat afternoon.
Winds will be prevail from the southwest through tomorrow morning,
then shift westerly tomorrow afternoon. Wind speeds should prevail
at 10kt or less.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...Onton
LONG TERM...Auten
AVIATION...Shimon
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1041 PM EDT Fri Sep 16 2016
.UPDATE...
Issued at 1041 PM EDT FRI SEP 16 2016
Current forecast is generally on track. Overall seeing a
diminishing trend to shower and thunderstorm activity across the
entire area. However, had to extend timing of pops a couple of
hours in our south to account for lingering showers there. Still
anticipating the possible redevelopment of activity late tonight
in the north as shortwave energy tracks deeper into the Mid-West.
Otherwise adjusted grids for hourly obs and freshened up the zones
to remove evening wording.
UPDATE Issued at 810 PM EDT FRI SEP 16 2016
Adjustments to the forecast package was mainly for shower and
thunderstorm activity. Most of our activity this evening is
diurnally driven and has begun to dissipate with sunset. However,
shortwave approaching the Mid-West this evening is expected to
keep activity going further north and west of our area and may
impact our northernmost counties through the overnight. Based on
current trends believe this approaching feature is even now
helping to maintain ongoing activity along and west of I-75 and
across our Blue Grass counties. Did bring grids in line with
hourly trends. Also nudged grids later tonight towards latest
CONSShort blended solution, which appears to have a better handle
than usual on the current trends.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 311 PM EDT FRI SEP 16 2016
For the rest of this afternoon isolated showers and thunderstorms
will occur, mainly across the southern and eastern part of the
forecast area. Most areas will not see any rain this afternoon
though. Until forcing increases with the approach of the upper
level trough and surface cold front later in the weekend,
convection should remain scattered at best.
The models have not been handling the near term weather very
well. This includes the HRRR, which last night was more aggressive
with convection for today. As the day progressed the HRRR pulled
back on the afternoon convection but has recently been showing
more convection overnight, and even the GFS MOS is showing likely
probabilties of rain in spots tonight. Not surprisingly the CR
superblend came in with rather high probabilities tonight, but
mainly in the northeast part of the forecast area, with low
probability in the southwest. This at least makes sense with the
best chance for showers in the southwest this evening and the
northeast later tonight. With the model uncertainty in rain
chances will adjust the superblend precipitation probability with
the idea any convection will be spotty until Sunday and also
considering neighboring WFO forecasts.
.LONG TERM...(Sunday through Friday)
Issued at 311 PM EDT FRI SEP 16 2016
The period will begin with a shortwave trough moving across the
Great Lakes and Ohio Valley regions before pushing east of our
region by Monday morning. Nice weather, incident with height rises,
will ensue through midweek with upper level ridging building into
southeastern CONUS. This ridging is progged to remain in place
through the end of the period.
At the surface, a cold front will push through East Kentucky from
Sunday afternoon into Sunday night. High pressure will build in
behind the front on Monday and remain in place through Tuesday
morning. A quick-moving shortwave trough crossing through the Great
Lakes will push a weak cold front into the Ohio valley Tuesday
evening into Wednesday. This front is expected to wash out before
reaching our area and therefore shouldn`t provide the area with any
measurable precipitation. Another surface high builds into the
region Wednesday and should remain in place through the work week.
The only real chance for precipitation comes at the beginning of the
period with the trough and cold frontal passage. This combination
should produce showers and thunderstorms across the area Sunday
through Sunday night, with the best chance on Sunday afternoon when
there is plenty of instability for potential storms to tap into.
Beyond this frontal passage, the weather should remain warm and dry
with above normal temperatures, and slightly less humid conditions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 810 PM EDT FRI SEP 16 2016
Expect VFR conditions will prevail through the TAF forecast
period. Isolated to scattered showers and thunderstorms are
beginning to die down now that the sun has set. However,
approaching disturbance into the region appears to be helping to
maintain activity in the far west and into our Blue Grass areas.
Consequently will keep an eye on SYM in case some thunderstorm
activity manages to roll into that area later this evening. For
now went with VCSH through the overnight as thunderstorms have
been isolated in coverage in that area. Winds look light through
the overnight but will increase from the southwest Saturday ahead
of an approaching cold front. Looking further ahead, the best
chance for showers and thunderstorms still looks to be Sunday.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...SBH
LONG TERM...JVM
AVIATION...SBH/RAY
Area Forecast Discussion
National Weather Service Memphis TN
857 PM CDT FRI SEP 16 2016
.DISCUSSION...Water Vapor Satellite/WSR-88D Vad Wind profiles this
evening indicate a shortwave trough embedded within southwest flow
aloft moving across portions of the Middle and Lower Mississippi
Valleys this evening. This is resulting in showers and
thunderstorms from East Central Missouri back through Northwest
Arkansas and Eastern Oklahoma.
Latest 00Z WRF and HRRR indicate shower and thunderstorms should
begin to move into portions of Northeast Arkansas in the next 2-3
hours and across the remainder of the Mid-South overnight into
Saturday morning. It appears the best chances for showers and
thunderstorms will be mainly along and north of I-40 tonight and
areawide on Saturday. Will make some adjustments to rain chances
and any other elements as needed into tomorrow to account for
short term trends.
Updated grids will be available shortly.
CJC
&&
.PREV DISCUSSION... /issued 634 PM CDT FRI SEP 16 2016/
UPDATE...
Updated to include the 00z aviation discussion.
PREV DISCUSSION... /issued 320 PM CDT FRI SEP 16 2016/
DISCUSSION...
An upper ridge continues to bring hot summer time temperatures to
the Mid-South this afternoon. Temperatures are currently in the
lower to mid 90s. A few showers and thunderstorms have developed
mainly across northern portions of the Mid-South.
The ridge will break down tonight which will allow a cold front to
push into the Mid-South over the weekend. Numerous showers and
thunderstorms have developed along old outflow boundaries ahead of
the front across Missouri this afternoon. Latest HRRR, 4km NAM,
and WRF models show this convection pushing into Northeast
Arkansas later this evening. The convection will affect the
Missouri Bootheel and Northwest Tennessee during the overnight
hours.
Old outflow boundaries from this convection will likely then trigger
convection on Saturday afternoon. In fact, the WRF and 4km NAM
show redevelopment occurring roughly from the Ohio River
southward into Northeast Arkansas around 2-3 PM. However,
convection could develop anywhere at anytime on Saturday. Will go
with likely POPS across most of the CWA Saturday afternoon.
Chances for showers and thunderstorms will linger into Saturday
evening, but then expect a brief break early Sunday morning before
a shortwave moves into the area setting off additional showers and
thunderstorms. For now just have 30-40 POPS across the entire CWA
as too hard to pinpoint best timing and location. Highs may stay
in the mid to upper 80s over the weekend thanks to the convection
and abundance of cloud cover.
The shortwave will push east by Sunday evening as the cold front
washes out over North Central Mississippi. Surface high pressure
from the Ohio Valley will build into the area which will bring
drier air into region. However, there will be little reprieve from
the heat as the upper ridge gradually rebuilds over the region
from Monday through the end of next week. Temperatures will
return to the lower to mid 90s.
KRM
&&
.AVIATION...
/00z TAFs/
Sustained convection has had a difficult time across the Mid-South
this afternoon, but widespread showers and thunderstorms continue
to the north and west of the CWA. This activity will sag slowly
south and east overnight, gradually weakening with the loss of
heating and the corresponding increase in convective inhibition.
We do anticipate convection in the vicinity of KJBR by midnight,
but the remaining forecast terminals are likely to remain dry much
of the night. Scattered warm advection showers are expected to
develop during the early morning hours in the warm sector, with
additional convection forming in the vicinity of the approaching
cold front.
While drier air is expected to work in the KJBR area tomorrow
afternoon, the rest of the area will remain warm and humid with
scattered diurnal showers and thunderstorms. Winds will generally
be light from the south overnight, but should veer southwesterly
on Saturday. We should see northwest winds at KJBR by early
afternoon as the surface boundary passes.
Johnson
&&
.MEG Watches/Warnings/Advisories...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Omaha/Valley NE
1045 PM CDT FRI SEP 16 2016
.SHORT TERM...(Tonight through Monday)
Issued at 325 PM CDT FRI SEP 16 2016
Little in the way of impactful short term weather. Near surface
soil moisture is high across the area due to heavy rainfall Thursday
night into early Friday morning. RAP, SREF and HRRR and conditional
LAMP guidance each hinting at some patchy ground fog, with
visibilities perhaps dropping down into the 6 to 8 mile range.
Decided to introduce a period of patchy fog from about 09 UTC
through 13 UTC. Diurnal mixing will dissipate any ground fog that
may form.
Saturday night into early Sunday, there is a slight chance of
nocturnal convection, as short wave feature enhances isentropic
ascent 305-312K. Moisture appears limited to mid-levels so not
confident that coverage will be too great. As such kept PoPs
below slight chance.
Temperatures will be seasonal through the weekend, and forecast
guidance looked reasonable and accepted consensus. By late in the
short range, temperatures will be on the rise, as mid-level ridging
builds over the central U.S. Downslope component to wind will allow
max temperatures to jump 5-10 degrees from Sunday to Monday.
.LONG TERM...(Monday night through Friday)
Issued at 325 PM CDT FRI SEP 16 2016
Upper flow remains predominately zonal across northern plains,
with large scale H5 ridging entrenched over southern plains. H5
heights suggests temperatures will remain slightly above
normal through Wednesday. Deterministic and ensemble models are
consistent in moving a cold front across the region Wednesday
evening into Thursday. Best dynamic forcing will be well to the
north of the forecast area, and question how far south front will
push as it encounters mid- level ridging across the southern
plains. As such, some sort of boundary linger across the area
providing a focus for convection. Thermodynamic/diabatic effects
will be enough to generate some convection and consensus solution
of low chance PoPs entering amd remaining in the forecast from
Wednesday night into Friday looks reasonable.
&&
.AVIATION...(06Z TAFS for KOFK...KLNK and KOMA.)
Issued at 1045 PM CDT FRI SEP 16 2016
VFR conditions are expected through the period.
&&
.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&
$$
SHORT TERM...Fortin
LONG TERM...Fortin
AVIATION...Boustead
Area Forecast Discussion
National Weather Service Blacksburg VA
911 PM EDT Fri Sep 16 2016
.SYNOPSIS...
High pressure will keep a wedge in place over our area overnight.
By Saturday, high pressure will still be located in the area with
Julia stuck offshore of South Carolina. A cold front enters the
Ohio and Mid Mississippi Valley Sunday, moving through the mid-
Atlantic states Monday.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 845 PM EDT Friday...
Shallow wedge remains in place tonight with low clouds having
already filled back in along the Blue Ridge after loss of heating.
However less low deck over far southern sections where the evening
GSO raob showed a much drier boundary layer under a bit steeper
inversion aloft. Also some breaks showing up across the Mountain
Empire region along the periphery of the cool pool, and where
earlier spotty convection developed near the instability gradient.
Therefore still cant rule out an isolated shower far western
ridges through midnight given leftover weak
convergence/instability just west of the area, but since iffy wont
include. Otherwise expecting low clouds to become more widespread
again overnight as trapped low level moisture spreads out, while
eventually lowering enough to result in spotty fog/drizzle espcly
eastern slopes of the Blue Ridge by daybreak. Thus beefed up
clouds from the Blue Ridge east and included more fog and patchy
drizzle late. Also lowered temps a degree or two in spots,
although only expecting slow falls, mainly back into the 60s,
given cloudiness and higher dewpoints overnight.
Previous discussion as of 345 PM EDT Friday...
A dirty wedge continues to dominate the region as low clouds were
seen by most today. Some areas did see clearing over the course of
the day, but will more than likely cloud over again this evening
as little change to the pattern is expected through Saturday
afternoon. At that point, some clearing can be expected and
temperatures should rebound a bit through the mountains. Current
HRRR shows that the best chances for precip for the duration of
the day exist over the Grayson Highlands and the Northwest
Mountains of NC, however rainfall amounts look to be very minimal.
More widespread showery activity should be anticipated on Saturday
ahead of an upper level trof approaching the region.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 300 PM EDT Friday...
The weather pattern remains blocked with high pressure over the
western Atlantic. This blocking pattern will keep Tropical Storm
Julia hovering off the southeast coast and a cold front sitting over
the midwest Saturday night. A northern stream upper level trough
will begin to push the cold front slowly across the Ohio Valley
Sunday, then over the Mid Atlantic States Sunday night into Monday.
Prefrontal showers may clip the Greenbrier Valley Saturday night
into Sunday afternoon, but the bulk of the widespread light rain
will move across with the front Sunday night into Monday. Not much
forcing with the passage of this front, but enough lift may squeeze
out a half of an inch /0.50/ of rain across southeastern West
Virginia and around quarter of an inch /0.25/ over the southwestern
Virginia and northwest North Carolina mountains. The flow becomes
westerly fairly quickly as the front tracks across the mountains
Monday morning to limit rainfall to under a quarter of an inch east
of the Blue Ridge. A secondary line of showers may develop over the
piedmont Monday afternoon. At this time, models have this line
developing well east of Blacksburg CWA and in the coastal piedmont
of Virginia. Showers will taper off from west to east Monday
afternoon as the upper level trough pivots over the region.
Temperatures will warm above seasonal levels until the frontal
passage Monday.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 330 PM EDT Friday...
A cold front slides across the region Monday night, but clouds will
likely remains as theta-e ridging lingers over the area. The upper
level trough is expected to become a closed low over the
southeastern states as it begins to interact with Tropical Storm
Julia. An upper level ridge will build east from the Gulf States
Wednesday and center itself over the Carolinas by next weekend. This
ridge could take Julia westward across Florida and into the Gulf of
Mexico. For the immediate area, this ridge will bring several days
of warmer than normal temperatures and little chances for rain.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
As of 645 PM EDT Friday...
Variable cigs will continue into this evening with VFR to high end
MVFR across the western and eastern perimeters with MVFR central
sections closer to the Blue Ridge where the wedge remains deeper.
Isolated showers/storms could also affect KBLF in the next hour
or two before loss of heating so may need to include a vicinity
mention there. Otherwise plenty of uncertainty exists with the
fluctuation of cloud height and coverage this evening before the
wedge starts to deepen again overnight. This scenario as
suggested by most short term models and forecast soundings should
cause cigs to once again lower through MVFR to IFR most spots
overnight including the addition of some patchy fog and/or drizzle
late.
Wedge should erode a bit quicker on Saturday as the flow turns
more southerly allowing cigs to improve to VFR from west to east
into the afternoon. Only exception may again be along the Blue
Ridge and points northeast to around KLYH where sub-VFR cigs may
hang on longer. Therefore delayed improvement to VFR there until
early/mid afternoon. Appears any showers well ahead of the front
will remain confined to the far west including the KBLF-KLWB
vicinity, but since late in the valid TAF period wont include any
mention for now.
Extended aviation discussion...
Cold front edges east but remains well west of the mountains
Saturday night. Appears best chance of seeing pockets of sub- VFR
Saturday night will remain along the KBLF-KLWB corridor with
showers just ahead of the front. Otherwise appears mostly VFR cigs
Saturday night with some patchy fog around as moisture increases.
Sunday-Monday still looks unsettled as a cold front sags slowly
east across the region. Expect threat of showers and storms with
possible sub-VFR cigs/vsbys espcly later Sunday into Sunday night
mountains, and across the east later Sunday night into Monday.
Anticipating a return to more widespread VFR Tuesday into
Wednesday with weak high pressure building in behind the front
through midweek.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...RCS
NEAR TERM...JH/JR
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...AMS/JH/JR
Area Forecast Discussion
National Weather Service SAN ANGELO TX
654 PM CDT FRI SEP 16 2016
.AVIATION...
/00Z TAFS/
Scattered showers and thunderstorms are approaching the KABI
terminal early this evening and will affect the terminal between
00Z and 03Z. KSJT may see some SHRA/TS move into the area between
02Z and 05Z. Expect possible wind gusts to 45 KT, along with
temporary MVFR ceilings/visibilities. Confidence is lower across
the southern terminals regarding convection and will not mention
at this time. VFR conditions expected on Saturday, with scattered
afternoon convection developing mainly across the KABI and KSJT
terminals.
&&
.PREV DISCUSSION... /issued 314 PM CDT FRI SEP 16 2016/
SHORT TERM...
(Tonight and Saturday)
The NAM and GFS models both close an upper low off the southern
California/northern Baja coast overnight while an upper high
builds over southern Texas. This will place the forecast area in a
roughly zonal upper flow aloft. Both the HRRR and the NAM and to
some degree the GFS bring disturbances in the flow aloft over the
mid and upper portions of the CWA this evening. Will therefore
place the best chance of rainfall over the Big Country with lesser
POPs over the mid-section of the CWA. As the upper high over
southern Texas builds further northward and over the southern
portions of the CWA during the day on Saturday,the best chance of
rainfall will be relegated to the northern half of the forecast
area.
Will not see much change in the highs and lows over the area with
morning lows in the upper 60s to around 70 and the afternoon highs
around the 90 degree mark.
15
LONG TERM...
(Saturday night through next Friday)
Models have continued to trend drier for the long term forecast.
There is a weak shortwave currently moving southeast through the
ID/MT area this afternoon that is expected to make its way into
the southern plains by Saturday night. As this trough swings
through, an MCS may develop across the Caprock area and move
southeast into the northern half of our CWA late Saturday night
into Sunday morning. Will go ahead and keep slight chance to
chance PoPs in the forecast from Saturday night into Sunday for
this reason.
After Sunday, the ridge builds and strengthens from the Southern
Plains east into the Carolinas. This will return us to more
summer-like conditions, keeping our high temperatures 5 to 10
degrees warmer than normal, and precipitation chances low.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 70 89 69 93 / 50 30 20 20
San Angelo 70 92 69 94 / 30 20 10 10
Junction 70 93 70 95 / 10 20 10 10
Brownwood 71 91 70 93 / 40 30 10 20
Sweetwater 68 88 69 92 / 60 30 20 20
Ozona 71 92 69 93 / 20 20 10 10
&&
.SJT Watches/Warnings/Advisories...
None.
&&
$$
99/99/24
Area Forecast Discussion
National Weather Service Albuquerque NM
350 AM MDT SAT SEP 17 2016
.SYNOPSIS...
A heightened threat of severe thunderstorms is expected for one
more day across much of eastern New Mexico today before a drier
and much less active pattern develops Sunday and Monday. Much of
western New Mexico should remain storm free through the weekend. A
closed low aloft developing southward just offshore of far southern
California today will remain nearly stationary through Monday
before opening up and lifting northeast early next week. After the
drying trend to start the new week, this system will pull moisture
northward again and enhance thunderstorm chances from Tuesday
through Wednesday. A much stronger low pressure system could
deliver significant changes for late next week.
&&
.DISCUSSION...
Cluster of showers and thunderstorms in the vicinity of Los Alamos
and Santa Fe with isolated activity now beginning to develop/expand
farther east across the northeast highlands per latest model
trends. Latest RAP objective meso analyses suggest a fairly broad
region of modest upper level divergence just north of a 250-300mb
jet axis that continues to cut across southern New Mexico. That
coupled with lift ahead of positively tilted shortwave trough
crossing the central Rockies should provide favorable environment
through remainder of the morning for isolated to scattered
SHRA/TSRA. Made some minor adjustments to PoP/wx for NC/NE areas.
Elsewhere, areas of stratus have slowly expanded along/east of
the central mountain chain but have yet to see signs of convective
precip development for EC/SE zones. Appears the focus will be
just east of the NM/TX line but 06z NAM continues bullish trend
thru 18z.
Otherwise, main wx concern after 18z will be the potential for
severe storms across the east once again, especially the
southeast. Boundary layer flow veering to SW and surface dew
points in the 40s across the northeast may preclude significant,
sustained threat there. But backed low level flow looks to
maintain mid 50 to near 60 dew points east of the Pecos River and
south of the Caprock region beneath fast westerlies aloft where
severe potential should be greatest -- to include much of eastern
Lincoln, Chaves, De Baca, Curry and Roosevelt counties. That
being said, the latest NAM and GFS not overly impressive with QPF
despite impressive instability parameters. So coverage may be more
isolated across our CWA with better coverage with east/southward
extent. The west should again remain quiet save for the the
activity this morning and perhaps isolated activity over the
higher terrain NC/NW.
Sunday and Monday trending noticeably drier/less active areawide
as 50mb heights rise and drier air across the far west and Four
Corners advances eastward . Closed low aloft developing southward
just offshore of far southern California today will remain nearly
stationary through Monday before opening up and lifting northeast
early next week. Could get nice bump in moisture across the west
later Tuesday into Wednesday.
All eyes then shift to what could be an especially dynamic/impactful
stretch of weather late next week but significant model differences
keeping uncertainty quite high. The GFS continues to show an
anomalously deep/large upper low taking aim on the southern
Rockies while the 00Z ECMWF has trended deeper than its previous
run but weaker than the GFS and thus remains more progressive. We
often mention a secondary severe weather season this time of year,
and the pattern Thursday-Saturday fits that conceptual model
quite well even if the more progressive ECMWF were to verify. Stay
tuned... kj
&&
.FIRE WEATHER...
A dry west to northwest flow aloft will result in a dry day for all
but the far eastern plains today. Isolated thunderstorms will be
possible across the eastern plains this afternoon before drier air
from the west wins out all areas Sunday. Sunday continues to look
like the first day since sometime back in July with no
thunderstorms/lightning strikes anywhere in the state. Minimum
relative humidity values are forecast to drop below 15 percent across
all but the southeast plains Sunday and Monday afternoons.
Four Corners high is forecast to build northwestward late-day Sunday
into Monday, allowing temperatures to warm above seasonal averages
both days. Weather prediction models agree that the upper high will
get pushed east of New Mexico Tuesday. The upper high gets shoved
east as an upper level low drops into the PACNW, sending a weak
upper low off of the southern California coast northeastward.
Monsoon moisture will increase across western New Mexico in
southwest flow aloft head of the California low. This moisture and
the associated showers and thunderstorms spread east across the
remainder of the forecast area Wednesday and continue through at
least Friday.
Model solutions diverge next weekend. GFS wants to deepen the upper
trough/closed low as it drops southeastward into the Great Basin.
ECMWF is farther north until the trough moves east of the Rockies,
then it splits the low with the southern portion deepening over the
southern plains. These differences would result in major sensible
weather differences across NM next weekend. GFSensemble mean is not
too far removed from the operational GFS but the same is true for
the operational ECMWF and its ensemble mean.
33
&&
.AVIATION...
06Z TAF CYCLE
VFR conditions prevail and are forecast to persist at KFMN, KGUP,
KAEG, KABQ and KSAF. An east canyon/gap wind is peaking between
15-20kts sustained at KABQ currently, but will be trending down
over the next several hours. MVFR cigs are forecast to develop
overnight at KLVS and KROW, and possibly at KTCC. Improvement
Saturday morning at KROW should be slow. KROW may be impacted by
storms late Saturday afternoon moving southeast off of the higher
terrain to the west. 11
&&
.PRELIMINARY POINT TEMPS/POPS...
Farmington...................... 81 43 83 43 / 0 0 0 0
Dulce........................... 77 32 78 35 / 5 0 0 0
Cuba............................ 74 40 77 43 / 5 0 0 0
Gallup.......................... 79 33 82 35 / 0 0 0 5
El Morro........................ 76 34 78 39 / 0 0 0 5
Grants.......................... 80 37 81 41 / 0 0 0 5
Quemado......................... 78 42 80 46 / 0 0 5 5
Glenwood........................ 84 52 86 55 / 0 0 5 5
Chama........................... 70 33 71 36 / 10 5 0 0
Los Alamos...................... 74 46 77 48 / 20 5 0 0
Pecos........................... 74 44 77 47 / 30 10 0 0
Cerro/Questa.................... 72 38 75 42 / 20 10 0 0
Red River....................... 61 32 65 34 / 30 10 0 0
Angel Fire...................... 68 28 71 30 / 30 10 0 0
Taos............................ 74 36 77 39 / 20 10 0 0
Mora............................ 70 40 75 44 / 40 10 0 0
Espanola........................ 79 48 82 50 / 20 10 0 0
Santa Fe........................ 74 46 77 49 / 20 10 0 0
Santa Fe Airport................ 78 45 81 47 / 20 10 0 0
Albuquerque Foothills........... 81 52 82 52 / 5 5 0 0
Albuquerque Heights............. 83 54 84 55 / 5 5 0 0
Albuquerque Valley.............. 85 51 86 51 / 5 5 0 0
Albuquerque West Mesa........... 84 53 85 53 / 5 0 0 0
Los Lunas....................... 85 52 86 53 / 5 5 0 0
Rio Rancho...................... 84 51 85 53 / 5 5 0 0
Socorro......................... 87 54 87 55 / 5 5 5 0
Sandia Park/Cedar Crest......... 76 46 78 48 / 10 5 0 0
Tijeras......................... 80 45 81 51 / 10 5 0 0
Moriarty/Estancia............... 77 42 79 47 / 20 10 0 0
Clines Corners.................. 76 44 78 47 / 20 10 0 0
Gran Quivira.................... 78 48 80 51 / 10 10 5 0
Carrizozo....................... 82 54 84 56 / 10 10 10 5
Ruidoso......................... 75 48 78 52 / 10 20 20 5
Capulin......................... 74 44 80 47 / 40 30 0 0
Raton........................... 77 42 82 46 / 40 30 0 0
Springer........................ 77 42 83 45 / 40 20 0 0
Las Vegas....................... 74 44 80 47 / 30 10 0 0
Clayton......................... 79 53 85 53 / 40 40 0 0
Roy............................. 75 47 83 50 / 40 30 0 0
Conchas......................... 82 57 88 57 / 40 20 0 0
Santa Rosa...................... 82 54 87 55 / 30 20 0 0
Tucumcari....................... 84 58 90 57 / 40 30 0 0
Clovis.......................... 81 58 87 56 / 40 30 5 5
Portales........................ 80 59 87 57 / 30 30 5 5
Fort Sumner..................... 82 59 88 57 / 30 20 0 0
Roswell......................... 85 60 90 59 / 30 30 10 5
Picacho......................... 80 55 85 56 / 30 20 10 10
Elk............................. 77 52 80 54 / 20 20 10 10
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
41
Area Forecast Discussion
National Weather Service Buffalo NY
530 AM EDT SAT SEP 17 2016
.SYNOPSIS...
Showers and a few thunderstorms will bring wet weather ahead of a
slow moving cold front that will cross the region this weekend.
While the bulk of the rain is expected later today into tonight,
showers will linger into Sunday before drying out Monday. Another
cool front will swing through Tuesday, bringing a slight chance for
showers before high pressure brings more dry weather for the middle
of the coming week. Today will be the warmest day of the period with
80s in some locations today and 60s tonight. Temperatures will cool
somewhat behind the front, but will still run near to slightly above
average through much of the coming week.
&&
.NEAR TERM /THROUGH TONIGHT/...
A look at regional MRMS radar mosaic this morning illustrates the
broad synoptic picture quite nicely. An initial widely scattered
band of showers can be found along a warm front arcing from NE Ohio,
across Southern Ontario and across Georgian Bay into a surface low
centered near the Boundary Waters of Minnesota. A second, much more
consolidated and impressive band of rainfall can be found stretching
from the Middle Mississippi valley across Indiana and into Lower
Michigan. This second area of rainfall is occurring ahead of a cold
frontal boundary in an area of favorable synoptic lift with falling
heights and plenty of DPVA aloft courtesy of an upstream upper level
low and associated troughing over the upper Midwest. A robust SSW-
NNE oriented LLJ of 30-40kts at 850mb is advecting a healthy supply
of GOMEX moisture into the aforementioned pre-frontal zone, with
pwats exceeding 1.75 inches.
The aforementioned low pressure system will gradually track east-
northeast into Quebec over the next 24 hours. As for this
morning...a cluster of showers and thunderstorms over NE Ohio is
gradually moving up the Lake Erie shoreline towards PA/NY at the
moment and bears watching...however it is progged to fall apart by
HRRR guidance. While we may still see scattered shower activity
across portions of Western and North-Central New York this morning
as the associated warm frontal boundary lifts across the area, the
bulk of the rainfall will likely hold off until later this afternoon
and the arrival of the pre-frontal trough, low-level jet, and the
main slug of moisture. This band of rainfall will then gradually
makes its way across the forecast area overnight tonight.
Given the favorable dynamics, ample supply of GOMEX moisture, with
anomalously high pwats in excess of 1.75 inches, and the roughly
front-parallel flow in the upper levels, resulting slow forward
motion, the stage is set for the forecast area to receive some much
needed rainfall. Ensemble guidance suggests widespread accumulations
in excess of an inch are possible over the next 24 hours, with
localized amounts exceeding 2 inches across the higher terrain east
of the lakes through tonight.
In addition to the abundant rainfall, there will be at least a
marginal threat for severe weather, as would be expected given the
35-40kt 925-850mb jet that will be arriving over Western New York
late this afternoon into this evening. While instability will not be
overly impressive, with forecast CAPEs in the neighborhood of 500
j/kg, the abundant shear will be supportive of bowing segments that
may produce localized wind damage.
With plenty of warm and moist air advecting across the region ahead
of the cold front, it will be yet another warm September day across
the forecast area. The addition of gusty southerly winds and
associated downsloping will push the mercury even higher across the
Genesee valley and Lake Ontario plains, where the mercury will break
the 80 degree mark, with upper 70s expected elsewhere. The warm and
moist airmass will linger through tonight, with lows only expected
to fall into the mid to upper 60s across most areas.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Low pressure will track from eastern Ontario province on Sunday into
central Quebec Sunday night with a trailing cold front slowly
shifting east across western into central New York. A parent mid
level trough axis will shift east from the Midwest states to western
New York by Monday morning. A plume of seasonably high 1.25-1.50in
Pwats should be found ahead of the cold front suggesting plenty of
moisture available for shower potential although NAM BUFKIT point
soundings are showing a weak 700mb cap and limited instability of
500-1000 j/kg CAPE. This weak cap and modest instability will limit
any thunderstorm threat to just a few rumbles of thunder within
better organized cells Sunday focused toward the southern Finger
Lakes region into south-central NY. The lowest POPs have been placed
over the Niagara Frontier.
Temperatures will continue to run above mid-Sept normals with highs
ranging from the low 70s across the higher terrain to upper 70s
along the southern Lake Ontario shoreline and Genesee Valley.
Dewpoints in the mid 60s will add an elevated humidity factor as
well. Chances of showers will linger into Sunday along the slow
moving front. Low temps will also remain very mild only slipping
back into upper 50s/low 60s Sunday night.
On Monday the mid-level trough will cross New York pushing the front
and associated deeper synoptic moisture east into New England.
Incoming dry air and surface high pressure briefly building in
behind the departing front will help clear skies and provide mainly
dry weather with just a slight chance of a shower east of Lake
Ontario. Another frontal system will cross the central lakes Monday
night to just west of Buffalo. This second front is what will
finally knock back dewpoint temps into the more comfortable range of
50s F for midweek. Highs Monday will run in the mid to upper 70s for
most with a few isolated 80 degree readings possible toward the
Finger Lakes. Another mild night with lows only slipping back to
between the mid 50s inland to mid 60s toward the lake shores.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A near zonal flow along the Canadian border during this period will
mark the northern extent of a sub tropical ridge that will initially
be centered over the Southern Plains. As we progress deeper into the
week...the ridge will drift east and amplify over the Ohio Valley.
This whole scenario will guarantee that our temperatures will
average above normal throughout this period. In fact...the mercury
will be roughly 10 deg F above 30 year norms with highs generally in
the mid to upper 70s. These readings will be more typical of mid
August.
On a day to day basis... A weak cold front will cross our region on
Tuesday. The aforementioned sub tropical ridge will block any GOMEX
moisture from making its way int our region though...so the moisture
starved frontal passage will only be accompanied by sparse shower
activity. Have kept slight chance POPs for most with low chance pops
focused east of Lake Ontario.
High pressure over the upper Mid West Tuesday night will then push
east across the Lower Great Lakes for Wednesday. This will supply
our region with a period of fine weather with light winds and
comfortable temperatures.
As the surface high moves off the Mid Atlantic Coast...another weak
cold front will settle to the south across our region Thursday and
Friday. Again...the front will be moisture challenged and with
little frontogentic forcing expected...the opportunity for showers
again looks limited. Will continue to use low chance pops for the
bulk of the region.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
High clouds continue to overspread the region early this morning in
advance of a low pressure system currently centered along the
Minnesota/Ontario border. A warm front lifting north across the
region ahead of this system will bring a low chance of showers this
morning, however the bulk of any shower/thunderstorm activity will
likely hold off until this afternoon, mainly after 18Z, when the
main zone of lift and moisture associated with the system is
expected to move across the forecast area.
Expect mainly VFR conditions with periods of MVFR in heavier showers
this afternoon. In addition, there will be enough instability and
synoptic forcing to support at least a chance of thunderstorms this
afternoon and evening as the cold front associated with this system
nears the area. In addition to the MVFR conditions, expect gusty SW
winds to develop from 15Z onwards with gusts of 20-30kts possible
this afternoon. With increasing moisture across the area and
potential widespread rainfall, expect cigs to lower tonight to MVFR,
with IFR cigs developing across higher terrain of the Southern Tier
and the Tug Hill Plateau after 03Z.
Outlook...
Sunday...Conditions returning to mainly VFR with showers diminishing.
Monday...VFR.
Tuesday...Mainly VFR with a chance of showers.
Wednesday...VFR.
&&
.MARINE...
A warm front lifting across the region bringing freshening southerly
winds is building waves on the lakes this morning, however most of
this wave action is confined to Canadian waters. The one exception
is in eastern Lake Ontario, near the entrance to the Saint Lawrence
River, where waves are expected to build in excess of 4 feet today.
A small craft advisory for this area and accompanying Beach Hazard
Statement for Jefferson County have been issued through this
afternoon.
Otherwise, look for a brief lull in winds/waves across eastern Lake
Ontario late this afternoon into this evening as flow veers to the
WSW. The break will be short-lived however as the WSW winds freshen
and gradually veer more westerly tonight as a slow-moving cold front
crosses the lakes. Another round of small craft advisories, this
time including eastern Lake Erie as well, have been issued to cover
this. Winds and waves will gradually diminish through the day on
Sunday with more tranquil conditions on Monday as high pressure
transits the area.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Beach Hazards Statement until 2 PM EDT this afternoon for
NYZ007.
MARINE...Small Craft Advisory from 8 PM this evening to 5 AM EDT Sunday
for LEZ020-040-041.
Small Craft Advisory until 2 PM EDT this afternoon
for LOZ045.
Small Craft Advisory from 8 PM this evening to 8 AM EDT
Sunday for LOZ045.
&&
$$
SYNOPSIS...WOOD
NEAR TERM...WOOD
SHORT TERM...SMITH
LONG TERM...RSH/WOOD
AVIATION...WOOD
MARINE...WOOD
Area Forecast Discussion
National Weather Service Charleston SC
407 AM EDT Sat Sep 17 2016
.SYNOPSIS...
The region will remain situated between Tropical Depression Julia
meandering off the Southeast U.S. coast and inland high pressure
through early next week. A cold front will advance into the region
by the middle of next week, stalling just south of the region as
high pressure builds from the north.
&&
.NEAR TERM /THROUGH TODAY/...
An inland wedge of high pressure will hold firm today as Tropical
Depression Julia continues to meander well offshore and weaken.
Broad, synoptic-scale subsidence and extensive mid-level dry air
induced by a strong southwest-northeast oriented upper level
ridge extending from from the eastern Gulf of Mexico, across the
Southeast U.S coast to offshore the the Mid-Atlantic states will
support another dry and warm day. Lowered pops slightly from the
previous forecast, only showing 20% pops for parts of the
Charleston Tri-county area where both the RAP and H3R show a few
showers developing mid-late afternoon. K-indices are progged to
remain in the lower teens so the Troposphere still remains too
dry to support tstm development. Highs will range from around 90
across interior Southeast Georgia to the upper 80s elsewhere away
from the coast. Highs may be held down just a bit north of I-26
corridor where low-stratus advecting in from the northeast may
limit thermal rises after sunrise.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
Tonight: High pressure wedging will remain in tact as Julia
transitions to a remnant low well offshore. Temperatures will
drop steadily after sunset as any lingering cumulus away from the
coast should dissipate with the loss of insolation. Any isolated
showers that can spawn in the northeast low-level flow look to
remain confined to the coastal waters where boundary layer
moisture will be the most plentiful. Conditions favor another
round of stratus either developing over the area or propagating in
from the northeast after midnight. Most of the statistical
guidance show some degree of a stratus deck prior to sunrise,
which coincide with the low 1000 hPa condensation pressure
deficits noted in the 17/00z NAM12. The boundary layer will
decouple inland, so some of the stratus could translate to some
fog. Lows will range from the upper 60s well inland to the upper
70s at the beaches.
Sunday through Tuesday: Surface high pressure covering the
eastern United States and ridging aloft will cause the remnants of
Julia to further weaken offshore. Higher PWATs will remain further
offshore as the high pressure inland wins out. Though, isolated
showers associated with the weakening system may work across the
coastal waters and possibly reach the South Carolina beaches.
Heights aloft will begin to fall Sunday night as broad troughing
shifts eastward from the Great Plains. The remnants of Julia will
deteriorate rapidly into a wave as the upper level wind speeds
increase during this time. A cold front will approach the area
Monday, pushing the remnants of Julia out to sea. Increasing
moisture ahead of the front combined with increased instability
justify chance POPs by Monday. This should be the best day for
thunderstorm potential, especially in the afternoon. However, given
the low amplitude of the trough and the modest WAA ahead of the
front, the severe threat remains low.
The front will cross through our area Monday night and stay to our
south on Tuesday. High pressure building into our area from the
north will bring drier conditions.
Temps will be near to a few degrees above normal thanks to the ridge
overhead and increasing WAA early next week.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
The cold front will be far to our south Tuesday night while high
pressure to the north builds into our area and brings drier
conditions. The high will dominate our weather through the end of
next week. Showers should remain mostly confined to the coastal
waters. Though, it`s possible some could move onshore, especially
towards the end of this time period. Hence, we have periods
featuring slight chance POPs for the coastal counties while further
inland is dry. Temperatures will generally be near normal.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
KCHS: Short term models show another round of low-stratus
potentially impacting the terminal prior to sunrise. The bulk of
this looks to remain north in the KMNI-KMKS-KGGE vicinity, but may
drop into the terminal by 11-12z. Will carry a tempo group for
low-end MVFR cigs for now. VFR otherwise.
KSAV: VFR. Could see a very brief chance for MVFR cigs right
around sunrise, but current thinking most of the low-stratus will
remain to the north.
Extended Aviation Outlook: Showers may bring brief flight
restrictions Sunday and Monday, especially in the afternoon.
&&
.MARINE...
Today: The pressure gradient will remain pinched today between
inland high pressure and Tropical Depression Julia. The tightest
gradient will remain confined to the Charleston County and Georgia
offshore waters where NE winds 15-20g25 kt will persist. Expect
slightly lower winds elsewhere. Long period easterly swells from
Julia and wind wave will support combined seas 2-4 ft nearshore
waters from Edisto Beach south to the Georgia coast with 4-6 ft
over the Charleston (AMZ350) and Georgia offshore waters (AMZ374).
A Small Craft Advisory will remain in force for AMZ350-374 mainly
for seas and frequent gusts to 25 kt.
Tonight: Conditions will finally begin to improve as Julia
continues to wind down and inland high pressure holds form. The
tighter gradient looks to shift farther offshore which will allow
winds to gradually diminish. Seas will diminish a bit as well, but
6 ft seas will linger over the Charleston County and Georgia
offshore waters through this evening.
Sunday through Wednesday: Julia is forecasted to weaken off the
Southeast U.S. coast on Sunday. Our waters will remain on the
western periphery of the weakening circulation, which will allow
northeast winds to prevail. The remnants of Julia will be pushed
further offshore on Monday as a cold front approaches the waters.
The front will pass through our area Monday night, moving south of
our area on Tuesday. High pressure to our north will then build into
our area, generating a return to northeast winds. Seas are expected
to subside to 1-2 ft by Monday night.
Rip currents: Long period 10-11 second easterly swell from Julia
combined with astronomical influences from the current full moon
will keep the rip risk at moderate today. An elevated risk will
continue through Sunday as the swell from Julie slowly fades.
&&
.TIDES/COASTAL FLOODING...
Early morning extratropical storm surge guidance once again brings
both the Charleston Harbor and Fort Pulaski tide gages to shallow
coastal flooding thresholds with this morning`s high tide cycle,
but just barely. Since there is still a slight offshore component
with the low-level wind field and surface pressures are running
1-2 hPa higher than 24 hours ago, will once again hold off on the
issuance a Coastal Flood Advisory and monitor trends. The need for
an advisory will be reevaluated during the next several hours as
high tide approaches.
A Coastal Flood Advisory will likely be needed for all or portions
of the coast with the higher, evening high tide cycle.
Shallow salt water flooding will be possible once again Saturday,
mainly during the evening along the South Carolina coast. As we
move further from the full moon and the northeast flow decreases
as Julia weakens Sunday, the threat for shallow coastal flooding
should subside.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for AMZ350-
374.
&&
$$
ST/MS
Area Forecast Discussion
National Weather Service State College PA
548 AM EDT SAT SEP 17 2016
.SYNOPSIS...
A moist southerly flow ahead of a slow moving cold front will
bring an increasing chance for showers across the western half of
the state later this morning and this afternoon. The chance for
showers and scattered thunderstorms will increase elsewhere across
central the central mountains and Susq Valley late today into
Sunday.
Rainfall totals by late Sunday will likely be near one inch in
many locations. A few places could see slightly heavier amounts.
Improving conditions with decreasing humidity will occur Monday
through at least early Thursday as a large area of high pressure
builds in from the Midwest.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Areas of strato cu were noted across the South-Central Mtns...and
especially over the Lower Susq Valley where skies were bkn-ovc early
today as a result of a southerly 925-850 mb flow. Partly cloudy
skies in the form of cirrus were observed between the route 219
and I-99/RT 220 corridors.
Conditions will stay dry through 12z and beyond over most of the
CWA.
Low temps around sunrise will vary from around 50F over the
western Poconos, with mid to upper 50s over the northern and
western mtns. Readings over portions of the Middle and Lower Susq
Valley will be in the 60-65 degree range as a result of the bkn-
ovc strato cu deck.
Moisture will continue to increase today ahead of slow moving
frontal system approaching from the Ohio Valley overnight and
tomorrow.
The chance for showers will be on the increase during the late
morning/early afternoon hours west of the I-99 corridor...with
locations just east of the I-99/RT220 corridor likely staying dry
until 19-20Z per the last several runs of the HRRR that depict a
lead band of convection (showers and scattered TSRA) forming along
a prefrontal trough.
The deterministic NAM and SREF are most aggressive in bringing
showers east today, while the bulk of other operational guidance
(HRRR and GEFS) are slower and suggests more in the way of just
scattered showers and isolated thunderstorms in the increasingly
humid and unstable airmass.
A pair of weak/fast moving upper jetlets will lift NE from
eastern Ohio and cross far NW PA...bringing the most
frequent/heaviest showers and embedded tsra to that region this
afternoon/evening.
SPC has roughly the NW 1/3 of the CWA in a Marginal Risk for SVR
TSRA this afternoon and evening...thanks to a 30-40kt southerly
925-850 mb jet with decent streamline convergence just to the west
of this wind max. Further east...gradually weaker llvl winds and
slight diffluence/anticyclonic curvature to the flow should
minimize the areal coverage and intensity of the shra and tsra.
The showers through 21z will be confined mainly to the western
half of the state. 925-850 mb diffluent flow and speed divergence
will help to minimize the areal coverage rainfall amounts from
showers/isolated TSRA.
Highs this afternoon will be a few degrees warmer than Friday...
ranging from the mid 70s north to the lower 80s in the southeast.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
Cfront will gradually push east across the region after midnight
and slow as several weak waves of low pressure at the sfc and
aloft ripple newd along it. POPs through 12Z Sunday will be likely
to categorical across the NW half of the CWA...with 35 to 60 POPs
near and to the SE of Interstate 81.
Low temps early Sunday will be mild and in the 60s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Little change in the high probability for frequent showers and
scattered TSRA Sunday and Sunday night across Central and Sern PA
as the cfront edges slowly sewrd.
some drying and lower pops should spread into the NW mtns Sunday
afternoon/evening...but will maintain chc pops there through
around midnight.
Afterward, there are no other notable times in the long-term
period when it is worth drawing POPs over 20. Even then only over
the far northern tier as weak fronts try penetrate the force field
over central PA.
Low pressure rolls through northern Ontario and Quebec early in
the period. The associated cold front checks in but does not check
out of PA as the boundary layer and upper flow become nearly
parallel. PW does not quite reach 2 inches, but the constant
southerly flow around the high pressure off the coast will yield
a long period of deep moisture. The front finally pushes through
Sunday night and early Monday. This is a bit of a slow-down from
previous forecasts, but probably to be expected with an already-
sluggish front and no real kicker of an upper trough. A minor
surface wave tries to form over the central Appalachians and track
over MD/SE PA right as the front finally looks to move out. So,
the heaviest rain could come to the southeastern zones on Sunday
night and early Monday.
The first part of the new week looks dry, with a surface high
overhead. A very weak and moisture-starved front moves along in
the progressive westerly flow and could make a passing shower
across the far north on Tues. But, again, it holds almost no hope
of rainfall for anyone, as the Gulf is cut off and drought does
beget drought. A warm front and perhaps light precip will set up
just to our north later in the week as we go from temps "only" 0
to 5F above normal back to temps some 10F warmer than normal by
mid-week. There might even be a run at 90F in the far southeast
later in the week. There is a hint in many of the models that the
front just to our north may try to inch southward in backdoor
fashion on Friday. However, we will keep day7 dry for now. Temps
through the period will remain 5 to 10F above normals for maxes
and mins - and mins might be 10+ above normal during the weekend
with all the clouds and moisture.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
A return of sub VFR is likely again overnight into Saturday as
moisture begins to increase ahead of an approaching cold front.
SERN terminals are likely to remain VFR longest as showery rains
take their time progressing eastward.
Outlook...
Sun...Scattered impacts as a slow moving frontal system moves
through the region.
Mon-Wed...no sig wx.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Dangelo/Lambert
AVIATION...Ross/Gartner
Area Forecast Discussion
National Weather Service Hastings NE
416 AM CDT SAT SEP 17 2016
.SHORT TERM...(Today and tonight)
Issued at 351 AM CDT Sat Sep 17 2016
Today will be absolutely beautiful with light winds, mostly clear
skies, and highs in the upper 70s across south central Nebraska
to near 80 over north central Kansas. A sfc high will track east
across Kansas resulting in the light wind, which will shift from
westerly to southerly as we head through the day.
The primary forecast concern and point of uncertainty will
surround the chance of thunderstorms this evening. Moisture will
be very limited with dewpoints currently in the 40s to around 50
and these will climb only slightly by this evening into the the
lower 50s. A subtle hardly noticeable vort max/upper trough will
slide east off the high plains this evening. The 07Z HRRR is the
most aggressive with developing showers and thunderstorms across
eastern Colorado by late afternoon, which then push east into our
western zones predominately after 7 pm. Several WRF models also
indicate that this high plains convection could make it at least
into our western zones this evening. Therefore, have added a
chance of thunderstorms to the forecast for this evening leaning
towards the lower superblend POPs.
There will be at least a marginal severe weather threat off to our
west late this afternoon, but given our feeble instability
(SBCAPE 500-1000 J/KG) and the late hour of arrival as we lose
diurnal heating it seems that any storms should be weakening as
they make it into our western forecast zones. Given decent deep
layer shear of 30 kts and at least some initial limited
instability, can not completely rule out an initial strong storm
or two in our far west from Gothenburg, down to Beaver City, and
south into Plainville, KS.
Weakening thunderstorms will likely die out before midnight and
currently seem unlikely to make it any further east than Highway
281, but this should be watched and updated in future forecasts.
.LONG TERM...(Sunday through Friday)
Issued at 351 AM CDT Sat Sep 17 2016
Dry conditions remain in the forecast to start of the long term
period on Sunday, and are expected to continue into the first part
of the upcoming work week. By Sunday morning, models are in pretty
good agreement showing zonal to low amplitude northwesterly flow
having developed in the upper levels, in the wake of a departing
shortwave trough axis. Overall, not expecting a lot of change in the
overall pattern as we go through Sunday and even into
Monday/Tuesday. Upper level flow remains zonal, with the CWA set up
between high pressure building over the southern Plains and a
disturbance sliding east across Canada. Models not showing much in
the way of waves affecting our area, thus the forecast remaining
dry. At the surface, west-southwesterly winds are expected to be in
place during the day on Sunday, with high pressure over much of the
southeastern CONUS and a frontal boundary working its way in from
the west. This boundary looks to push through the area late Sunday
night into Monday, but not much in the way of impact is expected
outside of a switch to more northwesterly winds and lower dewpoints.
High pressure behind this boundary builds into the area for later
Monday/Monday night, before sliding off to the east, allowing for
southerly return flow for Tuesday. Forecast highs for Sun-Tues
remain in the 80s.
Looking to the mid-later portions of the week, there is more
uncertainty in the forecast, as precipitation chances make a return.
The upper level pattern across the Central Plains transitions to
southwesterly flow by Wednesday morning, as the ridge axis
associated with that southern Plains high gets pushed east of the
area by low pressure/troughing moving onto the West Coast. A more
organized upper level low pressure system is expected to start
working its way east into the Rockies through the Wed-Fri period,
but confidence isn`t the highest. There are notable differences
between models with the timing/track of this system, with the 00Z
ECMWF quicker/further north than the 00Z GFS. Hard to go higher than
20-30% chances at this point, lot of details with any lead
shortwaves are yet to be determined.
&&
.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Saturday night)
Issued at 1242 AM CDT Sat Sep 17 2016
VFR conditions will persist throughout the TAF valid period. The
wind will be rather light and shift from westerly to southerly
through the period as an area of sfc high pressure slides off to
the east. Low level wind shear will increase tonight (Saturday
night), but appears to be below the threshold where we would
include it in the TAF.
&&
.GID Watches/Warnings/Advisories...
NE...None.
KS...None.
&&
$$
SHORT TERM...Wesely
LONG TERM...ADP
AVIATION...Wesely
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
515 AM EDT Sat Sep 17 2016
.SYNOPSIS...
Tropical system Julia will linger just off the southeast coast over
the weekend then slowly dissipate, keeping the heavier rainfall
mainly over the coastal waters. A cold front will approach
the Western Carolinas Sunday, and move through the area early
Monday. Drier high pressure returns in its wake.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 230 AM...precip had yet to develop near the Blue Ridge, so
that has been eliminated for the time being, and we shall see if
upslope flow is strong enough to force anything in the pre-dawn
hours. Also in question is the development of low clouds and fog
from the east toward the Piedmont. Satellite imagery shows an area
of low stratus over the coastal plain moving slowly west, but it has
a way to go before reaching the fcst area. Temp trends look good for
now.
The next 24 hours look fairly quiet around the western Carolinas.
Although the upper ridge axis has moved well to our east and we come
under an increasing SW flow aloft with the broad upper trof located
over the Plains, our sensible weather will change very little from
yesterday. We remain under a weak sfc ridge in-between the
circulation of what is left of Julia off the Southeast Coast and a
cold front to the west. If anything, the boundary layer is expected
to be a bit drier this afternoon which will put an even greater
limit on deep convection over the mtns. Think it will be isolated at
best and close to the TN line. High temps should continue to run
about five degrees above normal. Most of the tonight period should
also be quiet, although the approach of a short wave from the west
and the development of some weak upper divergence suggest that
precip ahead of the cold front could encroach from the west toward
daybreak over the mtns. Precip chances start to ramp up before dawn
over the far W, otherwise most places should be dry. Min temps will
also remain seasonally mild.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 215 AM Saturday: A broad trough will push across the
Mississippi Valley on Sunday, as a high-amplitude upper ridge sits
over the western Atlantic. As the associated surface low pushes
toward Newfoundland, a cold front will trail it into the southeast
CONUS. The consensus of latest guidance brings this front through
our CWFA early Monday. Drier high pressure will build overhead in
its wake, though the impact on temperatures looks minimal.
Currently it appears we will remain in the prefrontal environment
through most if not all of the daytime hours Sunday. Winds are
expected to veer to west late in the day over the mountains
after peak heating. Unseasonably warm and humid conditions will
be felt at the surface. Lapse rates are not remarkably strong in
light of the incumbent ridge, but modestly unstable conditions
should develop. PoPs are allowed to increase diurnally, with the
mountains most likely to see precip before sunset. These chances
spread east and generally peak overnight as base of trough passes
and winds shift. It is expected that the drier and more subsident
air will settle over the NW half of the CWFA early enough on Monday
to permit a dry fcst there; over the Piedmont some instability
is expected to develop again, so a schc to low chc pop will
be maintained. Downsloping winds and actually slightly higher
thicknesses suggest Monday may be slightly warmer than Sunday at
some locations, though dewpoints will be a few degrees lower. Skies
should clear out Monday night though mins are expected to remain
several degrees above climo.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 130 AM Sat: As high pressure moves out of the northern Plains,
another weak cold front will push into the Ohio Valley Tuesday,
though global models suggest this will wash out before it reaches the
southern Appalachians. Low-level flow veers from northerly to
easterly over the CWFA through late week as that high migrates to the
East Coast. Warm and mostly sunny conditions will continue in this
pattern, with maritime moisture being shunted south of the area.
Temps will remain several degrees above normal, but dewpoints will be
more comfortable than they have been of late.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
At KCLT...VFR for the time being, but there are big questions about
the development of an IFR cloud deck to the east. Some of the model
guidance, in particular the LAMP, paints a very pessimistic picture
of widespread MVFR/IFR ceilings developing by daybreak, which has
yet to happen. The upslope flow does not look strong enough to force
that much low cloud development. Instead, the RUC idea that a low
cloud deck will move in from the east looks more plausible, which
agrees with satellite imagery at issuance time. Problem is, the RUC
brings the stratus and fog within sight of the air field before its
westward progress stops. The current motion of the low clouds seen
on satellite imagery has the leading edge reaching the air field
between 12Z and 13Z. Will bring in the low clouds at 12Z but keep
them sct for the time being, and await further developments. The low
clouds should scatter quickly by mid morning. Wind will begin ENE and
should switch to ESE in the mid afternoon, then go light and
variable after sunset.
Elsewhere...a low cloud deck near the Blue Ridge may result in some
VFR ceilings. Over the mtns, though, expect cloud bases to be lower
and in the MVFR range. Valley fog was already developing, so going
with a temporary IFR at KAVL is not a big stretch. This could easily
end up VLIFR by daybreak. The clouds should scatter by mid morning.
After that, VFR at all locations. Chances of showers this afternoon
are too small to mention.
Outlook: A cold front is expected to cross the area late in the
weekend, bringing small chances for showers, mainly to western
portions of the terminal forecast area on Sunday. Much drier air will
filter into the region early next week, which is expected to usher
in an extended period of VFR.
Confidence Table...
09-15Z 15-21Z 21-03Z 03-06Z
KCLT High 94% High 100% High 100% High 100%
KGSP High 87% High 96% High 100% High 100%
KAVL Med 77% High 83% High 100% High 100%
KHKY High 81% High 92% High 100% High 100%
KGMU High 85% Med 79% High 100% High 100%
KAND Med 75% High 92% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...Wimberley
NEAR TERM...PM
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...PM
Area Forecast Discussion
National Weather Service Lincoln IL
326 AM CDT SAT SEP 17 2016
.SHORT TERM...(Today and tonight)
ISSUED AT 326 AM CDT Sat Sep 17 2016
A band of showers and thunderstorms should be exiting east-central
and southeast Illinois early this morning, with the balance of the
forecast area likely to be dry through the period. The
showers/storms are associated with an upper-level disturbance
streaking across the area, along with an associated surface boundary.
While the model guidance suggests a dry day once the current
precipitation pushes east of the area, still a little concerned that
we may see a "surprise" shower/storm through tonight. An upper-level
low and associated troffing will still lie to our west for much of
the day, along with a surface cold front. These features are progged
to be weakening with time as they track east, but until they are
completely east of the area the threat of an isolated shower/storm
can`t be completely discounted. That being said, considering the
lack of precipitation and cloud cover upstream, and dryness of the
forecast soundings, do not plan to include PoPs beyond the current
morning rainfall. Notably cooler and less humid air will filter into
the region tonight behind the cold front, with low temperatures
tonight expected to fall into the 50s over most of the forecast area.
&&
.LONG TERM...(Sunday through Friday)
ISSUED AT 326 AM CDT Sat Sep 17 2016
Behind the exiting system, the forecast remains dry through the
remainder of the weekend, with mild temperatures. In the overnight
hours on Sunday, a narrow ridge at the sfc slips eastward and more
southerly winds at the sfc begin a short period of WAA, and slightly
warmer temps for Monday. ILX sits on the edge of a more zonal flow
across the northern tier of the country. A wave rippling through
that zonal flow across southern Canada drags a front through the
region later Monday/Monday pm. A bit of a wind shift with the front
and some minimal convergence at the sfc...warrants some low pops,
mainly for Mon night. Watching the timing for Mon afternoon,
particularly in the north. Mostly zonal flow just to the north
maintains the mild weather through mid week with warm temperatures
and quiet weather. Models portraying a pattern shift for the latter
half of the week as a large upper low digs out over the Pac NW and
amplifies the flow over the CONUS, putting the Midwest in
increasingly southwesterly flow. Typically, this would result in a
more active pattern with short waves rippling through the larger
scale trof. However, the GFS and ECMWF on the 00z runs are having
some differences in handling the western low. General consensus
breaks off part of the wave and isolates it in the southern high
plains...but major difference in the strength of the remaining
trof...as well as the location and potential cyclogenesis of the sfc
system associated with the cut off h5 low over the southern US.
Extended remains conservative at this point, there is a lot of
variability in the solutions for the forecast going into next
weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1150 PM CDT Fri Sep 16 2016
An extended period of forcing for precip will be affecting our
forecast area for the rest of the overnight, as a 500 mb
shortwave progresses NE across IL. The result will be steady rains
and isolated thunderstorms at the eastern terminal sites. HRRR and
upstream observations are pointing toward MVFR clouds developing
by 09z-10z, with IFR clouds near and shortly after sunrise
tomorrow.
It appears the back edge of the main wave of precip will reach
SPI and PIA before sunrise, with the other terminal sites seeing
rain tapering off by mid to late morning. Due to the upper trough
still affecting central IL, a few showers could develop for CMI
and DEC into early afternoon. However, most areas should see dry
conditions after 18z. VFR conditions and some clearing is
expected Sat afternoon from west to east.
Winds will be prevail from the southwest through tomorrow morning,
then shift westerly tomorrow afternoon. Wind speeds should prevail
at 10kt or less.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Bak
LONG TERM...HJS
AVIATION...Shimon
Area Forecast Discussion
National Weather Service North Platte NE
359 AM CDT SAT SEP 17 2016
.SHORT TERM...(Today and tonight)
Issued at 355 AM CDT Sat Sep 17 2016
The main concerns in the short term period centers around rain
showers/thunderstorms chances and the potential for strong and/or
severe thunderstorms. At the present time satellite imagery shows
clear skies and no significant weather occurring across the
forecast area. Warmer conditions are expected today, with highs
forecast in the lower 80s, about three to eight degrees above
normal. Above normal lows are then expected overnight, mid 40s in
the far western portion of the forecast area to low to mid 50s in
north central NE.
Weak 500 hPa height rises will be occurring at the start of the
period over western and north central NE as a broad 500 hPa
trough will be over the MN Arrowhead Region and far Upper Great
Lakes. The upper level trough will deamplify over the next 24
hours as it lifts eastward into the extreme eastern portion of
Ontario. In the meantime, a short wave trough is anticipated to
move east across south central WY to southwest NE to north
central KS by late this evening. This disturbance is expected to
provide weak large scale ascent and support convective
development as mid-level lapse rates steepen over northeast CO
and the NE Panhandle into western NE this afternoon and evening.
Meanwhile, broad surface high pressure currently over the Central
Plains will move eastward today and a weak lee side trough will
develop and deepen near the Front Range. Current thinking is that
convective development will be focused in this trough. Wherein
modest instability and sufficient moisture will combine with 0-6
km bulk shear generally about 20-35 kts that will be conducive
for organized multicells. Of which, moisture looks to be the
primary limiting factor and this could be attributable to the
amount of moisture being returned northward into the forecast
area today. Development is expected to move from northeast CO
into the forecast area and/or occur in southwest NE early-mid
evening with isolated to scattered coverage expected. Hi-res
deterministic guidance, HRRR and flavors of WRF, were in decent
agreement at the present time with forecast development shown
21-00Z today. Confidence in development is further increased
based on SPC SSEO output from the 00Z cycle today wherein a
strong signal appears present over southwest NE and northeast CO
for convection. The main risks will be strong winds and hail. Of
note, the latest SPC Day 1 Outlook has the southwest quad of the
forecast area in a marginal risk area, which seems appropriate if
storms can develop given aforementioned vertical wind shear.
Ultimately, a strong/severe storm or two could be possible today,
and cannot be ruled out. Any development is expected to taper
off/diminish in the late evening or move southeast out of the
area. After which, quiet conditions are expected.
.LONG TERM...(Sunday through Friday)
Issued at 355 AM CDT Sat Sep 17 2016
Generally upper level zonal flow overhead with a broad ridge
across the southern plains to begin the week. Thermal ridge Sunday
across the area with highs into the 80s. A weak cold front will
enter the picture on Monday. Models in disagreement on timing the
front through the southern part of the CWA. Expect the northern
part of the CWA to see about 5 degrees or so drop in temps from
Sunday, however less confidence for the area along and south of
I80. Forecast is conservative across the south and will continue
temps only a couple of degrees cooler, but would not be surprised
to see highs a degree or two warmer due to compressional heating
ahead of the front. Little moisture to work with and temps aloft
stay fairly warm for mid September and expect the passage of the
front to be dry with only some passing clouds. Thermal ridge
quickly rebuilds for Tuesday with temps expected to go back up.
Next upper level trough and sfc frontal passage is expected Wed.
Ahead of the front southerly winds will usher in some sfc moisture
which will aid in keeping lows very mild Wed morning, only falling
into the mid 50s and lower 60s. The return of sfc moisture will
result in a chance for precip with the passage of the front,
mainly in the east on Wed.
The trough will continue to push to the north with another trough
to dig to the west. The ridge will get shoved east with more SW
flow aloft. This will return some upper level moisture and bring a
better chance precip with several disturbances. Pops are low at
this time as model differences exist with waves. Expect at least
more mid and high clouds. Pending cloud cover which could keep
temps lower during the day, mos guidance still keeps afternoon
highs fairly close to seasonal averages or warmer.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1057 PM CDT Fri Sep 16 2016
Skies will mainly be clear across western and north central
Nebraska through midday Saturday. By Saturday afternoon, some mid
level clouds around 10000 FT AGL will begin to move into
southwestern and portions of western Nebraska. Some broken CIGS of
10000 FT AGL are possible at the KLBF terminal from 21z Saturday
through 02z Sunday. Isolated thunderstorms are possible across far
southwestern Nebraska during the late afternoon and early evening
hours on Saturday. However, at this time, activity is expected to
remain south and southwest of the KLBF terminal.
&&
.LBF Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...ET
LONG TERM...Masek
AVIATION...Buttler
Area Forecast Discussion
National Weather Service Lubbock TX
303 AM CDT SAT SEP 17 2016
.SHORT TERM...
Thunderstorms have started to develop along a weak surface
boundary/front across our southwestern zones. The boundary is hardly
discernible using surface obs as winds are light and vary variable,
but the boundary does show up on radar. This convective development
coincides with an upper level jet streak moving into the FA as shown
by WV imagery and a LLJ that has developed over the past few hours.
This activity is being pushed east northeastward by the mid and
upper level flow. The only model to pick up on this activity well is
the 00Z run of the TTU-WRF and keeps this activity going till after
sunrise before dissipating across our northeastern counties. The 06Z
run of the HRRR also shows this activity, but has it developed
further north than it currently is and pushes the convection
southeastward instead of northeastward and dissipated the convection
fairly quickly. Given the persistent and even strengthening LLJ, it
can be believed that convection could be sustained at least for the
next several hours.
Now for the big question: what will happen from later this morning
into tonight? Models have each given their thoughts on the matter,
and each thought is different from the other models. Given that the
higher res mesoscale models have performed the best recently, they
will be weighted more heavily in the forecast. An upper level
shortwave currently over northeastern UT/southwestern WY should
develop a lee trof by the late morning in CO, during which time
convection is progged to develop over the higher terrain of NM. The
terrain induced convection has the potential to push eastward into
the FA possibly merging with convection along the lee trof to form a
QLCS. The QLCS may push into our northern zones of the FA later this
evening , but current guidance keeps it northward in the TX and OK
Panhandles. For now chance PoPs for this evening will remain
unchanged due to the uncertainty of where the QLCS will go.
Aldrich
.LONG TERM...
The long term will serve up warm and dry weather as a change in
the upper pattern takes place early in the period. Upper level
ridging will build over the region Sunday with the center over or
near the region through Tuesday. Wednesday will see the ridge
shift to the east as an upper trough develops over the western
CONUS. It is looking more and more like energy from this trough
will remain well west of the forecast area, a trend noted in the
last several model runs. Really cannot pick out a period where
thunderstorm chances would be high enough to include in the
forecast, and will thus remove mention through Friday. Have again
trended temperatures toward MOS for Monday and Tuesday, slightly
higher than the model blend. Otherwise, the blend looks fine.
&&
.LUB Watches/Warnings/Advisories...
None.
&&
$$
51/07
Area Forecast Discussion
National Weather Service Paducah KY
344 AM CDT SAT SEP 17 2016
.SHORT TERM...(Today through Monday night)
Issued at 344 AM CDT Sat Sep 17 2016
Current radar trends indicate showers and isolated thunderstorms
moving across the region faster than previously forecast. The
latest HRRR and ECMWF seem to have a decent handle on the timing.
This lends itself to a quicker end to precip across the region,
with far western portions of the PAH forecast area precipitation
free by mid day, and all but far eastern portions dry by late
afternoon. Adjusted precipitation chances to reflect this trend,
and removed precipitation chances completely for late tonight and
Sunday. Temperatures will cool down just a little behind the cold
front to near seasonal readings.
High pressure will shift across our region for Sunday night into
Monday night. This will keep our region dry, and winds will shift
back to the south. Temperatures will warm back up to above
seasonal readings with highs Monday in the middle to upper 80s,
and lows Monday night middle to upper 60s.
.LONG TERM...(Tuesday through Friday)
Issued at 344 AM CDT Sat Sep 17 2016
Above average confidence through most of the period, then average
to below average at the very end due to model inconsistencies.
Very little to discuss and very few changes synoptically in the long
term period, especially if the ECMWF pans out. High pressure at the
surface and ridging aloft is forecast through the long term period
producing dry, warm, and humid conditions.
On Friday the GFS weakens and suppresses the upper ridge southward
allowing a back door cold front to sag into the far northern and
northeastern sections of our CWA and cranks out a bit of QPF in the
process. During the same time frame the ECMWF keeps the ridge
stronger and keeps all frontal boundaries and precipitation chances
well to our north. Will go with the more consistent ECMWF solution
for now and keep it dry every period.
Temperatures will remain at or above normal through the period.
&&
.AVIATION...
Issued at 1156 PM CDT Fri Sep 16 2016
Decaying MCS moving through southeast Missouri will continue to
weaken/dissipate as it moves slowly eastward overnight. TS has
really dropped off, and would be very unlucky to have even a stray
strike at KCGI or KPAH overnight. Not sure if there will be any
solid precipitation left as it tries to get to KEVV and KOWB
toward morning.
Latest HRRR guidance develops fresh band of convection near KEVV
around 15Z and pushes it eastward through KOWB through midday. Hit
this TS with a TEMPO group at both sites. Not sure if this will
develop back toward KPAH.
A weak surface trough/front will try to push through the area
Saturday, but ahead of it multiple outflow boundaries will muddle
wind fields overnight. Figure a southwest wind will develop most
locations in the morning, but not sure if it will ever really
shift to the northwest. KCGI is the best bet for a tangible wind
shift.
There is a strong signal for MVFR ceilings to develop in the
morning and persist for most of the day, if not into the evening.
Cannot even rule out IFR ceilings for awhile in the morning,
especially at KCGI.
&&
.PAH Watches/Warnings/Advisories...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...RST
LONG TERM...JP
AVIATION...DRS
Area Forecast Discussion
National Weather Service Pueblo CO
401 AM MDT SAT SEP 17 2016
.SHORT TERM...(Today and tonight)
Issued at 400 AM MDT Sat Sep 17 2016
...Threat of Severe Storms for the Southeast Plains Today...
Main concern today will be the threat of svr wx over the SE Plains
this afternoon. Will see CAPE of 1500-2000 j/kg and Bulk shear
around 40 Kts late this afternoon and early eve. A short wave
disturbance now seen on WV imagery moving into E UT-W CO will
push through SE CO this afternoon. This will set off SCT storms
over the Plains that will congeal into an MCS by early evening
over extreme E CO and W KS. The latest HRRR runs and the 4km
NAM are in good agreement with the evolution of convection this
afternoon. Storms will initially form from 18-19Z over the S Sangres
and Spanish Peaks Region, then coverage will expand to the NE
along a diffuse dry line. A broken line of storms should then
intensify and spread to the E-SE, moving into OK and SW KS by
early eve. Svr Parameters will support all types of severe
Wx...but the greatest threats will be for hail up to around golf
ball size, and wind gusts in excess of 60 mph. This threat will be
greatest over E Las Animas County and all of Baca County late this
afternoon.
Temps today will be considerably higher than yesterday...with highs
reaching the lower to mid 80s over the Plains and 60s-70s for the
Mts and high valleys. Expect clearing skies from W to E tonight,
which will lead to cool but seasonable overnight Lows, mainly in
the 40s-lower 50s for the Plains and 30s for the high valleys. Rose
.LONG TERM...(Sunday through Friday)
Issued at 400 AM MDT Sat Sep 17 2016
.Sunday and Monday...Upper level ridge develops over Colorado with
dry air aloft continuing to advect into the region from the west.
Anticipate warm and dry weather both days. With 700mb temperatures
around 10C to 12C, high temperatures will approach 90 degrees on
the plains both days, but temperatures will be at least several
degrees shy of the daily record highs.
.Tuesday...Upper trough moves into the Pacific Northwest on
Tuesday. Southwest flow ahead of the trough will bring moisture
northward into Colorado. Moisture appears to originate from a
potential tropical system which will develop off the coast of
Mexico. NHC currently has this system as a disturbance, and they
have a high probability of tropical cyclone formation. With a lee
trough over the plains keeping deeper low level moisture to the
east, chances for convection late Tuesday appear to be confined to
the mountains.
.Wednesday through Friday...GFS and EC start showing differences
with the track of the disturbance over the Pacific Northwest. EC
is faster moving the system to the east while the GFS is slower
and digs the trough into the Great Basin. Both models suggest that
diurnal convection will stay mostly over and near the mountains,
with generally downslope flow on the plains. The GFS brings a cold
front close to the northern portions of the CWA on Thursday. If
the front moves further south, upslope flow behind the front will
bring increased low level moisture with a better chance for
convection developing on the plains. --PGW--
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 400 AM MDT Sat Sep 17 2016
Some low cigs and patchy FG over the far SE Plains this
morning...mainly near the KS and OK borders, and should not affect
the TAF sites. Looks like storms today will be primarily well east of
I-25, so will leave mention of TS out of the TAFs, but an ISOLD
storm near the TAF sites cannot be ruled out this afternoon. Most of
the storms today will be SE of a line from KTAD to KLHX to KITR. Rose
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...ROSE
LONG TERM...PGW
AVIATION...ROSE
Area Forecast Discussion
National Weather Service Blacksburg VA
428 AM EDT Sat Sep 17 2016
.SYNOPSIS...
High pressure, both at the surface and aloft, will weaken and
shift east of the region through Sunday. An upper trough and
associated cold front will move into the region Sunday, taking
until Monday to move through the Piedmont. High pressure will
build over the region by Tuesday and linger through the end of
next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 400 AM EDT Saturday...
High pressure off the northern Mid-Atlantic coast will shift east
in response to an upstream trough/cold front approaching from the
Midwest. However, it will not do so soon enough to prevent another
mostly cloudy, relatively cool/mild day compared to most days this
month, which have been well above normal. The low clouds are
expected to erode across the Piedmont and west of the Alleghany
front by afternoon and in most areas by evening as the upper
trough/front continue to move into the region from the west.
However, this will not be soon enough to allow temperatures to
warm yet back to the pre-wedge levels we saw much of this past
week.
Precipitation is expected to be scarce again today. Most synoptic
and short-range models indicate that the best and initial dynamics
associated with the upper trough will move northeast toward the
Great Lakes/eastern OH valley. Showers and a few thunderstorms
will likely approach the northwest border of the CWA late in the
afternoon/evening but probably stop short of spreading into much,
if any, of the RNK CWA. The HRRR and NCEP WRF show little to no
precipitation spreading into the RNK CWA this afternoon/evening.
The first wave will go by overnight leaving us with just mid/high
clouds and little precipitation. Therefore, have confined pops to
slight chance/low chance along the western border to near zero
along and east of the Blue Ridge. Mentionable pops have generally
been confined to just the western most tier of counties, with the
highest pops from KBLF to west of KLWB.
As noted above, an increase in temperatures is expected today, but
should stop short of the 10F above normal readings we have seen
most days this month. Max temperatures today will be entirely
dependent on when the low clouds diminish. If this occurs late
morning, as opposed to the afternoon, advertised readings may be
too cool. Have leaned toward the cooler GFS gridded temperatures
as it seem to have the best depiction of the wedge air mass.
Minimum temperatures Sunday morning will be well above normal,
mostly in the 60s. We should be seeing lows in the 40s and 50s by
now!
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
As of 145 AM EDT Saturday...
The cold front that is expected to remain to our west today and
tonight, will make gradual headway eastward into and through the
region Sunday into Sunday night. Anticipate an increase in the
coverage of showers from west to east as the day progresses,
especially by the afternoon hours. Chances will be greatest in the
east during the evening and overnight hours. Model forecast
instability factors are not substantial, nor are they on the low
side. The forecast will reflect a slight chance for thunderstorms by
mid-day Sunday continuing only into the early Sunday evening hours.
The probability of showers will be in the likely category in areas
closest to the front.
By Monday morning, the front will have just exited, or be on the far
eastern edge of the forecast area. Slow progression eastward is
still forecast for this feature. It is expected to still be in close
enough proximity to allow for isolated to scattered showers across
eastern parts of the area. Forecast instability factors are more
impressive for thunderstorm development during the peak heating of
the day, especially the far eastern parts of the area by the late
afternoon. Other showers are forecast across the preferred upslope
regions of southeast West Virginia during the morning hours thanks
to residual low level moisture and an increasing upslope, northwest
flow in that region in the wake of the cold front.
Surface high pressure is expected to build across the Ohio Valley By
Monday night, and take on a west-east orientation with its axis
reaching the Delmarva peninsula by Tuesday night. Aloft, an upper
ridge is also expected to develop over the Tennessee and Ohio
Valleys. As geopotential heights build across the region, so too
will 850 mb temperatures.
Late night and early morning fog will be common through the period,
especially Sunday night and Monday night.
Despite the passage of a cold front, temperatures during this
portion of the forecast will continue to remain above normal for
this time of the year by five to ten degrees.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 PM EDT Friday...
High pressure, both surface and aloft, is expected to dominate
the region much of this period. An upper level trough is progged
to become a closed low over the southeastern states as it begins
to interact with Tropical Storm Julia, drifting west again back
toward the southeast U.S. coast. An upper level ridge will build
east from the Gulf States Wednesday and center itself over the
Carolinas by next weekend. This ridge could take Julia westward
across Florida and into the Gulf of Mexico. For the immediate
area, this ridge will bring several days of warmer than normal
temperatures and little chances for rain.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
As of 200 AM EDT Saturday...
Weak wedge holding across the area with widespread MVFR cigs
already in place. Main question will be whether or not these
evolve into any IFR cigs as the night progresses. Based on
guidance and current trends, this seems reasonable, so have
advertised about a four hour window of IFR cigs at most sites in
the 10Z-14Z time frame, after which cigs should improve to MVFR,
and most likely to VFR in the 16Z-18Z time frame as the wedge
continues to weaken. HRRR and other models show little in the way
of meaningful precipitation reaching the CWA today, so have not
advertised. Feel that this will remain west to northwest of the
CWA, closer to the upper dynamics with an approaching short wave
and not be able to penetrate the weakening wedge air mass to any
appreciable degree. The cloud cover will probably prevent fog
development to much extent, except possibly at KBCB and KLWB.
Areas of HZ may be expected in the ROA/BCB/LYH area through mid-
morning. Later today and into the evening, high clouds will begin
to overspread the region from the west. Winds will remain mostly
E-SE through the period at speeds of 5-7kts with low end gusts
possible during the daylight hours at KBLF.
Medium confidence in cigs throughout the TAF valid period. Medium
to high confidence in vsbys through 14Z, then high confidence in
VFR vsbys through the remainder of the TAF valid period. Medium to
high confidence in wind speed/direction through the TAF valid
period.
Extended aviation discussion...
Approaching cold front edges east but remains well west of the
mountains Saturday night. Wedge front dissipates. This will leave
improved ceilings overall Saturday night/Sunday morning in
comparison to today. However, widespread mid/high clouds will
overspread areas west of the Blue Ridge. Appears best chance of
seeing pockets of sub-VFR cigs early Sunday will remain along the
KBLF-KLWB corridor with showers just ahead of the front. Patchy
MVFR fog will be possible each of the Alleghany front early
Sunday.
Sunday-Monday still looks unsettled as a cold front drifts slowly
east across the region. Expect threat of showers and a few
thunderstorms with possible sub-VFR cigs/vsbys espcly later
Sunday into Sunday night mountains, and across the east later
Sunday night into Monday. Anticipating a return to more widespread
VFR Tuesday into Wednesday with weak high pressure building in
behind the front through midweek.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB
SHORT TERM...DS
LONG TERM...RCS
AVIATION...RAB
Area Forecast Discussion
National Weather Service SAN ANGELO TX
325 AM CDT SAT SEP 17 2016
.SHORT TERM...
(Today and Tonight)
Bulk of the evening convection has now dissipated across West
Central Texas early this morning. Models have struggled to handle
the convection over the last few days across West Central Texas,
with the HRRR handling the short term better than the other models.
Thus, will lean towards its solution as a first guess to start the
forecast, with scattered convection developing late this afternoon
across the western portions of the area, mainly west of an Abilene
to San Angelo line. Like has happened the last few days, expect this
convection to spread east across the area into the evening hours.
As for temperatures, will not deviate much from what we have seen
the last few days. Readings have managed to climb into the upper 80s
and lower 90s across the area, and should be in the same range
today.
.LONG TERM...
(Sunday through Friday)
On Sunday, an upper level ridge will be centered across South
Texas/northern Mexico. A subtle upper level shortwave trough is
forecast to swing across North Texas which may aid in the
development of scattered showers and thunderstorms Sunday afternoon,
mainly across the eastern half of the forecast area. Any shower and
thunderstorm activity should dissipate by early evening. High
temperatures will be well above seasonal normals, in the low to mid
90s.
An upper level ridge will dominate the weather across West Central
Texas through much of the upcoming work week. Generally dry
conditions are expected along with above normal temperatures. Highs
through the first part of the work week will be in the low to mid
90s, with overnight lows in the upper 60s to lower 70s. The center
of the upper level ridge is then forecast to shift toward the South
Atlantic states, which will result in slightly cooler temperatures
for the second half of the work week. Expect highs mainly in the
upper 80s to lower 90s, with overnight lows in the in the mid to
upper 60s. The next upper level trough is forecast to approach the
area next weekend, possibly bringing an increasing chance of showers
and thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 90 69 93 72 / 30 20 20 5
San Angelo 92 69 95 71 / 30 20 10 5
Junction 91 70 95 71 / 20 10 20 5
Brownwood 91 70 93 70 / 20 20 20 5
Sweetwater 89 69 91 71 / 30 20 10 5
Ozona 91 69 93 70 / 20 10 5 5
&&
.SJT Watches/Warnings/Advisories...
None.
&&
$$
07/Daniels
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
534 AM MDT SAT SEP 17 2016
.AVIATION...
12Z TAF CYCLE
Area of showers and storms continues across the northeast
highlands near KLVS northeastward to just south of KRTN. Isolated
storms will remain possible across the eastern plains through the
morning hours. Very dry air aloft will keep areas west of the
central mountains convection free today. Favored area for
afternoon storms will be across the southeast plains, including
KROW. A few afternoon storms are also possible across the far
northeast plains. Dry air will spread eastward overnight, ending
convection across the east after midnight.
33
&&
.PREV DISCUSSION...350 AM MDT SAT SEP 17 2016...
.SYNOPSIS...
A heightened threat of severe thunderstorms is expected for one
more day across much of eastern New Mexico today before a drier
and much less active pattern develops Sunday and Monday. Much of
western New Mexico should remain storm free through the weekend. A
closed low aloft developing southward just offshore of far southern
California today will remain nearly stationary through Monday
before opening up and lifting northeast early next week. After the
drying trend to start the new week, this system will pull moisture
northward again and enhance thunderstorm chances from Tuesday
through Wednesday. A much stronger low pressure system could
deliver significant changes for late next week.
&&
.DISCUSSION...
Cluster of showers and thunderstorms in the vicinity of Los Alamos
and Santa Fe with isolated activity now beginning to develop/expand
farther east across the northeast highlands per latest model
trends. Latest RAP objective meso analyses suggest a fairly broad
region of modest upper level divergence just north of a 250-300mb
jet axis that continues to cut across southern New Mexico. That
coupled with lift ahead of positively tilted shortwave trough
crossing the central Rockies should provide favorable environment
through remainder of the morning for isolated to scattered
SHRA/TSRA. Made some minor adjustments to PoP/wx for NC/NE areas.
Elsewhere, areas of stratus have slowly expanded along/east of
the central mountain chain but have yet to see signs of convective
precip development for EC/SE zones. Appears the focus will be
just east of the NM/TX line but 06z NAM continues bullish trend
thru 18z.
Otherwise, main wx concern after 18z will be the potential for
severe storms across the east once again, especially the
southeast. Boundary layer flow veering to SW and surface dew
points in the 40s across the northeast may preclude significant,
sustained threat there. But backed low level flow looks to
maintain mid 50 to near 60 dew points east of the Pecos River and
south of the Caprock region beneath fast westerlies aloft where
severe potential should be greatest -- to include much of eastern
Lincoln, Chaves, De Baca, Curry and Roosevelt counties. That
being said, the latest NAM and GFS not overly impressive with QPF
despite impressive instability parameters. So coverage may be more
isolated across our CWA with better coverage with east/southward
extent. The west should again remain quiet save for the the
activity this morning and perhaps isolated activity over the
higher terrain NC/NW.
Sunday and Monday trending noticeably drier/less active areawide
as 50mb heights rise and drier air across the far west and Four
Corners advances eastward . Closed low aloft developing southward
just offshore of far southern California today will remain nearly
stationary through Monday before opening up and lifting northeast
early next week. Could get nice bump in moisture across the west
later Tuesday into Wednesday.
All eyes then shift to what could be an especially dynamic/impactful
stretch of weather late next week but significant model differences
keeping uncertainty quite high. The GFS continues to show an
anomalously deep/large upper low taking aim on the southern
Rockies while the 00Z ECMWF has trended deeper than its previous
run but weaker than the GFS and thus remains more progressive. We
often mention a secondary severe weather season this time of year,
and the pattern Thursday-Saturday fits that conceptual model
quite well even if the more progressive ECMWF were to verify. Stay
tuned... kj
&&
.FIRE WEATHER...
A dry west to northwest flow aloft will result in a dry day for all
but the far eastern plains today. Isolated thunderstorms will be
possible across the eastern plains this afternoon before drier air
from the west wins out all areas Sunday. Sunday continues to look
like the first day since sometime back in July with no
thunderstorms/lightning strikes anywhere in the state. Minimum
relative humidity values are forecast to drop below 15 percent across
all but the southeast plains Sunday and Monday afternoons.
Four Corners high is forecast to build northwestward late-day Sunday
into Monday, allowing temperatures to warm above seasonal averages
both days. Weather prediction models agree that the upper high will
get pushed east of New Mexico Tuesday. The upper high gets shoved
east as an upper level low drops into the PACNW, sending a weak
upper low off of the southern California coast northeastward.
Monsoon moisture will increase across western New Mexico in
southwest flow aloft head of the California low. This moisture and
the associated showers and thunderstorms spread east across the
remainder of the forecast area Wednesday and continue through at
least Friday.
Model solutions diverge next weekend. GFS wants to deepen the upper
trough/closed low as it drops southeastward into the Great Basin.
ECMWF is farther north until the trough moves east of the Rockies,
then it splits the low with the southern portion deepening over the
southern plains. These differences would result in major sensible
weather differences across NM next weekend. GFSensemble mean is not
too far removed from the operational GFS but the same is true for
the operational ECMWF and its ensemble mean.
33
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
41
Area Forecast Discussion
National Weather Service Albany NY
1024 AM EDT SAT SEP 17 2016
.SYNOPSIS...
A low pressure system will gradually approach and move across the
region through Monday bringing much needed rainfall to the area.
Conditions will become warm and muggy with the passage of the
system`s warm front tonight. Temperatures will run 10 to 15
degrees above normal.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Current forecast in good shape.
Precipitation across western NY has been weakening as it moves
east in agreement with HRRR forecast. Nudged back POPs across NW
CWA slightly for late afternoon and early evening. Onset of
persistent precipitation looks like it will take until at least
03z to start.
Meanwhile, for the remainder of today, high level cirrus clouds
will continue to stream into the region well ahead of an
approaching low pressure system. Overall cloud coverage will be
on the increase thickening and lowering especially later in the
day. Chances for showers moving into the western Adirondacks and
western Mohawk Valley increase as the system`s warm front
approaches. Heights will begin to fall aloft as the weakening
upper ridge shifts farther offshore and a trough moves across the
Great Lakes region.
Southerly winds will increase across the area during the day
becoming gusty. Winds will funnel up the Hudson River Valley where
they should be the strongest.
Despite the increasing cloud cover, the southerly flow will help
boost temperatures to above normal again with highs a couple
degrees warmer than Friday. Also dew points will rise through the
50s as the warm front gets closer to the region.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
Much needed rainfall on the way as slow moving low pressure system
approaches and crosses the region.
The system`s warm front is expected to lift across the region
tonight ushering a humid airmass in with dew points rising into
the 60s. Then the area will be in the warm sector as the cold
front gradually approaches from the Great Lakes region. Aloft
will have broad southwest flow and will have to wait on a short
wave trough to help push the boundary through Monday.
Showers are expected to overspread the area tonight with numerous
showers along with chances for thunderstorms Sunday into Monday.
The better chances for rainfall will be to the south and east of
the Capital District Sunday night into Monday ahead of the cold
front as it moves across area. The threat for thunderstorms is
introduced tonight as negative showalter values move into the
region. The mention of thunder is maintain into Monday. 0-6 km
bulk shear values are expected to be 30 to 40 knots however the
mid level lapse rates remain rather weak 5.5-6 C/km.
Overall expecting a widespread rainfall of 1 to 1 1/2 inches
across the local area. The system will tap into tropical moisture
from the Gulf of Mexico with precipitable water levels increasing
to over 1.5 inches ahead of the cold front so some of the storms
could produce some heavy downpours leading to ponding of water in
low lying and poor drainage areas.
It will be warm and humid through the weekend into early next
week. Temperatures will be 10 to 15 degrees above normal with dew
points in the 60s until the passage of the cold/cool front during
the day Monday.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A relatively quiet extended forecast is expected into late next week
with a secondary cold front moving through on Tuesday...and high
pressure building in for the mid week into THU. A cold front may
bring some isolated to scattered showers late FRI.
TUE-TUE Night...An upper level trough impacts the region with
isolated showers to scattered instability showers mainly north and
west of the Capital District/Berkshires according to the latest
GFS/ECMWF/CAN GGEM. A secondary cold front will be moving through
the region with weak cold H850 cold advection...as H850 temps fall
to +6C to +8C from the Capital District north and west...and +8C to
+11C south and east. High pressure will be ridging in from the
Midwest and Great Lakes Region. Highs will start above normal in the
mid 70s to lower 80s in the valleys...and upper 60s to mid 70s over
the hills and mountains. Lows will range from the upper 40s to
lower 50s over the Catskills and southern Adirondacks to mid and
upper 50s over the rest of the region.
WED-THU...The mid and upper level flow becomes more zonal by WED
night. A large sfc anticyclone builds in over the Northeast...and
East Coast with lots of synoptic-scale subsidence. Highs will trend
closer to seasonal normals on WED but will still be about 5 degrees
above normal for late Sept. Lows WED night in a decent radiational
cooling environment will be in the upper 40s to mid 50s. Some weak
low/mid ridging tries to build in aloft for THU...and the sfc high
drifts off the New England Coast. Strong low to mid level warm
advection commences with H850 temps rising back a couple standard
deviations above normal with +13C to +15C readings. Highs on THU
with increasing high clouds will be in the upper 70s to around 80F
in the lower elevations...and upper 60s to mid 70s over the higher
terrain.
THU night-FRI...In the relatively flat mid level flow...a weak cold
front approaches THU night into FRI. The moisture convergence looks
weak with this boundary at this time. Only a slight chc of showers
was kept in the grids from the mid Hudson Valley north and west for
FRI. Temps will finish above normal and similar to THU.
Overall...temps look to be above normal...and pcpn below normal in
the long term.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
High pressure continues to move east of New England this morning. A
warm front will slowly lift north/northeast from the Great Lakes
Region and Ohio Valley today with some rain moving in tonight.
Some IFR/LIFR mist/fog will dissipate at KGFL/KPSF especially
between 12Z-13Z...with VFR conditions returning. VFR conditions will
remain into this evening at all sites. Mid and high clouds will
continue to gradually increase into this afternoon. It will be
breezy.
The leading edge of warm advection rainfall/showers should arrive
between 01Z-05Z/SUN. VCSH groups are used initially. The cigs and
vsbys should begin as VFR...but gradually lower to MVFR levels
overnight....and perhaps IFR btwn 09Z-12Z. For now...have MVFR
CIGS/VSBYS.
The winds will be light to calm at KGFL/KPOU/KPSF early this
morning...but southerly at around 10 kts at KALB due to the
funneling effect up the Hudson River Valley. The winds will increase
from the south at 8-15 kts with some gusts close to 25 kts at KALB
this afternoon. The winds will lighten slightly to 5-10 kts
overnight at KGFL/KPOU overnight...but will be 10-15 kts at
KPSF/KALB with gusts around 20 kts. Low-level wind shear maybe
needed at KGFL/KPOU after 06Z if confidence increases.
Outlook...
Sunday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
Wind gusts into 20s today and this evening...
A low pressure system will gradually approach and move across the
region through Monday bringing much needed rainfall to the area.
Showers are expected to overspread the area tonight with numerous
showers along with chances for thunderstorms Sunday into Monday.
The better chances for rainfall will be to the south and east of
the Capital District Sunday night into Monday. Overall expecting
a widespread rainfall of 1 to 1 1/2 inches across the local area.
&&
.HYDROLOGY...
A low pressure system will gradually approach and move across the
region through Monday bringing much needed rainfall to the area.
Showers are expected to overspread the area tonight with numerous
showers along with chances for thunderstorms Sunday into Monday.
The better chances for rainfall will be to the south and east of
the Capital District Sunday night into Monday. Overall expecting
a widespread rainfall of 1 to 1 1/2 inches across the local area.
The system will tap into tropical moisture from the Gulf of
Mexico with precipitable water levels increasing to over 1.5
inches ahead of the cold front so some of the storms could produce
some heavy downpours leading to ponding of water in low lying and
poor drainage areas.
Based on the USGS (waterdata.usgs.gov/nwis/rt) streamflow are
running at less than 25th percentile across most the hydrological
forecast area.
Precipitation departures so far this year:
Albany NY: -3.54 inches
Glens Falls NY: -6.28 inches
Poughkeepsie NY: -10.44 inches
Bennington VT: -7.24 inches
Pittsfield MA: -8.03 inches
The U.S. Drought Monitor was released on September 15th and shows
drought conditions have worsened across portions of the Northeastern
United States as much of the region experienced above-normal
temperatures and below-normal precipitation. A (local) Drought
Information Statement was issued Friday evening (ALBDGTALY).
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/OKeefe
SHORT TERM...IAA
LONG TERM...Wasula
AVIATION...Wasula
FIRE WEATHER...IAA
HYDROLOGY...IAA
Area Forecast Discussion
National Weather Service Columbia SC
1115 AM EDT SAT SEP 17 2016
.SYNOPSIS...
High pressure will ridge into the forecast area from the north
today. Julia will linger just off the South Carolina coast
through Sunday then dissipate. Moisture associated with Julia
will stay east of the Midlands. A weak cold front will cross the
area Monday. High pressure will return to the area by the middle
of next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Low clouds will linger over the Midlands through the remainder of
the morning, dissipating after noon.
Surface high pressure will continue to ridge into the Carolinas
and Georgia from the north with Julia meandering off the coast
today into tonight. A mid-level capping inversion will limit
convective development this afternoon. Scattered cumulus are
expected from daytime heating but are not likely to develop into
showers. The HRRR does show isolated showers moving inland from
the coast but dissipating before they reach the forecast area.
Tonight, upper level ridging over the southeastern states will
retreat to the southwest as a trough moves into the Mississippi
River Valley. Lows tonight will be in the mid 60s to lower 70s. Models
are suggesting deeper moisture and lighter low level winds. It is
likely that stratus and fog will develop again tonight through
late Sunday morning.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
Julia is forecast to linger off the South Carolina coast early
next week. An upper level trough crossing the Mississippi River
Valley Sunday will cross our area on Monday. The associated weak
cold front should move into the area Monday.
The models are consistent with shallow moisture Sunday. The NAM
and GFS MOS have pops less than 20 percent, so continued to
forecast dry conditions. The shallow moisture and nocturnal
cooling with light wind should result in areas of fog during the
early morning hours.
There should be increased instability Sunday night and Monday
associated with the upper trough. Have indicated a chance of
showers and thunderstorms Sunday night into Monday evening.
The temperature guidance was consistent with highs in the upper
80s and lower 90s along with lows in the upper 60s to lower 70s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The GFS and ECWMF show surface ridging extending into the forecast
area from the north through the medium-range period. An upper
trough is forecast move off the coast Tuesday with ridging
building into the area. Julia is shown lingering near the
Southeast coast at least through early in the period. Much of the
moisture associated with Julia or the trough is depicted to stay
east or south of the forecast area. The GFS and ECMWF MOS have
pops less than 30 percent through the period with temperatures
mainly above normal.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
IFR ceilings will dissipate over the next few hours. No convection
is expected to impact the terminals today. Models have been
consistent and are in good agreement indicating restrictions late
tonight and into Sunday morning. Deeper moisture and lighter low
level winds will support low stratus and fog development.
MVFR/IFR ceilings and visibilities likely after 07z tonight, with
the possibility of lifr by early Sunday morning.
EXTENDED AVIATION OUTLOOK...Early morning fog and stratus remain a
possibility through the period with a chance of mainly
afternoon/evening thunderstorms early next week.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Charleston SC
1016 AM EDT Sat Sep 17 2016
.SYNOPSIS...
The region will remain situated between Tropical Depression Julia
meandering off the Southeast U.S. coast and inland high pressure
through early next week. A cold front will advance into the region
by the middle of next week, stalling just south of the region as
high pressure builds from the north.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
An inland wedge of high pressure will hold firm today as Tropical
Depression Julia continues to meander well offshore and weaken.
Broad, synoptic-scale subsidence and extensive mid-level dry air
induced by a strong southwest-northeast oriented upper level ridge
extending from from the eastern Gulf of Mexico, across the
Southeast U.S coast to offshore the Mid-Atlantic states will
support another dry and warm day.
Only slight chance for a few afternoon showers across mainly the
Charleston Tri-County area as a sea breeze develops. Broad scale
subsidence and minimal instability will limit coverage and
intensity.
Extensive stratus this morning will slowly burn off through early
afternoon. Given a fairly high sun angle and warm thicknesses,
temps should rebound quickly once even a few breaks start to
develop. Thus, despite continued overcast skies in southern SC, we
feel confident that highs will reach the upper 80s by the end of
the day.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
Tonight: High pressure wedging will remain in tact as Julia
transitions to a remnant low well offshore. Temperatures will
drop steadily after sunset as any lingering cumulus away from the
coast should dissipate with the loss of insolation. Any isolated
showers that can spawn in the northeast low-level flow look to
remain confined to the coastal waters where boundary layer
moisture will be the most plentiful. Conditions favor another
round of stratus either developing over the area or propagating in
from the northeast after midnight. Most of the statistical
guidance show some degree of a stratus deck prior to sunrise,
which coincide with the low 1000 hPa condensation pressure
deficits noted in the 17/00z NAM12. The boundary layer will
decouple inland, so some of the stratus could translate to some
fog. Lows will range from the upper 60s well inland to the upper
70s at the beaches.
Sunday through Tuesday: Surface high pressure covering the
eastern United States and ridging aloft will cause the remnants of
Julia to further weaken offshore. Higher PWATs will remain further
offshore as the high pressure inland wins out. Though, isolated
showers associated with the weakening system may work across the
coastal waters and possibly reach the South Carolina beaches.
Heights aloft will begin to fall Sunday night as broad troughing
shifts eastward from the Great Plains. The remnants of Julia will
deteriorate rapidly into a wave as the upper level wind speeds
increase during this time. A cold front will approach the area
Monday, pushing the remnants of Julia out to sea. Increasing
moisture ahead of the front combined with increased instability
justify chance POPs by Monday. This should be the best day for
thunderstorm potential, especially in the afternoon. However, given
the low amplitude of the trough and the modest WAA ahead of the
front, the severe threat remains low.
The front will cross through our area Monday night and stay to our
south on Tuesday. High pressure building into our area from the
north will bring drier conditions.
Temps will be near to a few degrees above normal thanks to the ridge
overhead and increasing WAA early next week.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
The cold front will be far to our south Tuesday night while high
pressure to the north builds into our area and brings drier
conditions. The high will dominate our weather through the end of
next week. Showers should remain mostly confined to the coastal
waters. Though, it`s possible some could move onshore, especially
towards the end of this time period. Hence, we have periods
featuring slight chance POPs for the coastal counties while further
inland is dry. Temperatures will generally be near normal.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
KCHS: As expected, low stratus has reached the terminal a few
hours ago with cigs OVC006. Intermediate observations from the
ASOS ceilometer have been as low as OVC300-400 or below alternate
minimums. Expect LIFR to persist through 14z before rapidly
improving. The stratus layer is rather thin per RAP soundings.
Should see VFR through early evening. Conditions point to a
potentially more widespread stratus event tonight.
KSAV: The leading edge of a stratus deck is on target to reach the
terminal by 12z. Will highlight cigs just below alternate minimums
through about 1330z with conditions rapidly improving thereafter.
Expect VFR through this evening. Conditions point to a
potentially more widespread stratus event tonight.
Extended Aviation Outlook: Showers may bring brief flight
restrictions Sunday and Monday, especially in the afternoon.
&&
.MARINE...
Today: The pressure gradient will remain pinched today between
inland high pressure and Tropical Depression Julia. The tightest
gradient will remain confined to the Charleston County and Georgia
offshore waters where NE winds 15-20 g25 kt will persist. Expect
slightly lower winds elsewhere. Long period easterly swells from
Julia and wind wave will support combined seas 2-4 ft nearshore
waters from Edisto Beach south to the Georgia coast with 4-6 ft
over the Charleston (AMZ350) and Georgia offshore waters (AMZ374).
A Small Craft Advisory will remain in effect for AMZ350-374
mainly for seas and frequent gusts to 25 kt.
Tonight: Conditions will finally begin to improve as Julia
continues to wind down and inland high pressure holds form. The
tighter gradient looks to shift farther offshore which will allow
winds to gradually diminish. Seas will diminish a bit as well, but
6 ft seas will linger over the Charleston County and Georgia
offshore waters through this evening.
Sunday through Wednesday: Julia is forecasted to weaken off the
Southeast U.S. coast on Sunday. Our waters will remain on the
western periphery of the weakening circulation, which will allow
northeast winds to prevail. The remnants of Julia will be pushed
further offshore on Monday as a cold front approaches the waters.
The front will pass through our area Monday night, moving south of
our area on Tuesday. High pressure to our north will then build into
our area, generating a return to northeast winds. Seas are expected
to subside to 1-2 ft by Monday night.
Rip currents: Easterly swell from Julia combined with astronomical
influences from the current full moon will keep the rip risk at
moderate today. An elevated risk will continue through Sunday as the
swell from Julie slowly fades.
&&
.TIDES/COASTAL FLOODING...
A Coastal Flood Advisory will likely be needed for all or
portions of the coast with the evening high tide cycle.
Shallow salt water flooding will be possible once again Sunday,
mainly during the evening along the South Carolina coast. As we
move further from the full moon and the northeast flow decreases
as Julia weakens Sunday, the threat for shallow coastal flooding
should subside.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for AMZ350-
374.
&&
$$
NEAR TERM...JRL
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service State College PA
1159 AM EDT SAT SEP 17 2016
.SYNOPSIS...
A moist southerly flow ahead of a slow moving cold front will
bring an increasing chance for showers across the western half of
the state later this morning and this afternoon. The chance for
showers and scattered thunderstorms will increase elsewhere across
central the central mountains and Susq Valley late today into
Sunday.
Rainfall totals by late Sunday will likely be near one inch in
many locations. A few places could see slightly heavier amounts.
Improving conditions with decreasing humidity will occur Monday
through at least early Thursday as a large area of high pressure
builds in from the Midwest.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Showers in a wide line stretching from western NY into the
Laurels. The rainfall is not heavy by any means. Operational HRRR
and RAP keep insisting on weakening the showers in time. However,
some bit of expansion/filling-in has been noted over the last 4-5
hours. Again, this stuff is jnot heavy, but is going to dampen
many outdoor activities. The current trajectory of the rain is
just about stright to the NE. The motion and orientation of the
area of showers will keep it over the northern mountains for a
few hours. There is an area of clearing just to the west of KBFD
which stretches all the way into southern OH and is allowing for
better surface heating and advection of 70+ dewpoints to the
north. This is the area to watch for deep convection/thunder and
any worry of severe weather for later this afternoon and evening.
Prev...
Areas of strato cu were noted across the South-Central Mtns...and
especially over the Lower Susq Valley where skies were bkn-ovc early
today as a result of a southerly 925-850 mb flow. Partly cloudy
skies in the form of cirrus were observed between the route 219
and I-99/RT 220 corridors.
Conditions will stay dry through 12z and beyond over most of the
CWA.
Low temps around sunrise will vary from around 50F over the
western Poconos, with mid to upper 50s over the northern and
western mtns. Readings over portions of the Middle and Lower Susq
Valley will be in the 60-65 degree range as a result of the bkn-
ovc strato cu deck.
Moisture will continue to increase today ahead of slow moving
frontal system approaching from the Ohio Valley overnight and
tomorrow.
The chance for showers will be on the increase during the late
morning/early afternoon hours west of the I-99 corridor...with
locations just east of the I-99/RT220 corridor likely staying dry
until 19-20Z per the last several runs of the HRRR that depict a
lead band of convection (showers and scattered TSRA) forming along
a prefrontal trough.
The deterministic NAM and SREF are most aggressive in bringing
showers east today, while the bulk of other operational guidance
(HRRR and GEFS) are slower and suggests more in the way of just
scattered showers and isolated thunderstorms in the increasingly
humid and unstable airmass.
A pair of weak/fast moving upper jetlets will lift NE from
eastern Ohio and cross far NW PA...bringing the most
frequent/heaviest showers and embedded tsra to that region this
afternoon/evening.
SPC has roughly the NW 1/3 of the CWA in a Marginal Risk for SVR
TSRA this afternoon and evening...thanks to a 30-40kt southerly
925-850 mb jet with decent streamline convergence just to the west
of this wind max. Further east...gradually weaker llvl winds and
slight diffluence/anticyclonic curvature to the flow should
minimize the areal coverage and intensity of the shra and tsra.
The showers through 21z will be confined mainly to the western
half of the state. 925-850 mb diffluent flow and speed divergence
will help to minimize the areal coverage rainfall amounts from
showers/isolated TSRA.
Highs this afternoon will be a few degrees warmer than Friday...
ranging from the mid 70s north to the lower 80s in the southeast.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 AM SUNDAY/...
Cfront will gradually push east across the region after midnight
and slow as several weak waves of low pressure at the sfc and
aloft ripple newd along it. POPs through 12Z Sunday will be likely
to categorical across the NW half of the CWA...with 35 to 60 POPs
near and to the SE of Interstate 81.
Low temps early Sunday will be mild and in the 60s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Little change in the high probability for frequent showers and
scattered TSRA Sunday and Sunday night across Central and Sern PA
as the cfront edges slowly sewrd.
some drying and lower pops should spread into the NW mtns Sunday
afternoon/evening...but will maintain chc pops there through
around midnight.
Afterward, there are no other notable times in the long-term
period when it is worth drawing POPs over 20. Even then only over
the far northern tier as weak fronts try penetrate the force field
over central PA.
Low pressure rolls through northern Ontario and Quebec early in
the period. The associated cold front checks in but does not check
out of PA as the boundary layer and upper flow become nearly
parallel. PW does not quite reach 2 inches, but the constant
southerly flow around the high pressure off the coast will yield
a long period of deep moisture. The front finally pushes through
Sunday night and early Monday. This is a bit of a slow-down from
previous forecasts, but probably to be expected with an already-
sluggish front and no real kicker of an upper trough. A minor
surface wave tries to form over the central Appalachians and track
over MD/SE PA right as the front finally looks to move out. So,
the heaviest rain could come to the southeastern zones on Sunday
night and early Monday.
The first part of the new week looks dry, with a surface high
overhead. A very weak and moisture-starved front moves along in
the progressive westerly flow and could make a passing shower
across the far north on Tues. But, again, it holds almost no hope
of rainfall for anyone, as the Gulf is cut off and drought does
beget drought. A warm front and perhaps light precip will set up
just to our north later in the week as we go from temps "only" 0
to 5F above normal back to temps some 10F warmer than normal by
mid-week. There might even be a run at 90F in the far southeast
later in the week. There is a hint in many of the models that the
front just to our north may try to inch southward in backdoor
fashion on Friday. However, we will keep day7 dry for now. Temps
through the period will remain 5 to 10F above normals for maxes
and mins - and mins might be 10+ above normal during the weekend
with all the clouds and moisture.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
Showers passing rather slowly per earlier expectations.
Orientation and movement still keep them mainly to the NW of and
AOO-UNV-IPT line into the mid afternoon. MVFR cigs do cover a
large portion of the area, but clearing/VFR over the west will
likely self-destruct into TSRA later today. Have kept timing of
the major changes in flight categories and winds the same with 15z
update.
Prev...
A cluster of TSRA is already nearing KBFD, but weakening as they
do so. Other SHRA across SW PA are also tracking to the NE but
could brush KJST as they pass mainly to the north of that
location. Isolated to scattered SHRA will impact the western
terminals almost all morning, and heating will help to bubble up
additional SHRA/TSRA as the afternoon begins. The central
mountains including KAOO and KUNV will likely have a mainly dry
morning, but the next wave of forcing comes along in the early-to
mid-afternoon time frame. Heating will destabilize the atmos and
cause SHRA/TSRA in the afternoon - but mainly after 3 PM.
Steering flow will push the SHRA to the NE and may impact KIPT
mid- to late-afternoon. Low-end VFR and high-end MVFR cloud slab
over most of the eastern half of the area will lift some and break
up. But, heating will be limited - at least this morning - so
destabilization will be less likely until very late in the day.
Sunset will help to decrease the amount and coverage of showers,
but a focus of some sfc convergence remains over the NW and
central terminals. Expect KMDT and KLNS to keep dry for the
longest period, but by 12z Sun, they may also be wet. MOS guidance
for KIPT drops them into IFR cigs later tonight. With high
moisture and winds which go calm/light, this seems reasonable.
A frontal boundary will be tough to draw tonight into Sunday
night, but slightly drier air will work in Sunday night and
Monday. Until then, SCT SHRA and ISOLD TSRA are expected for most
of the area.
Outlook...
Sun...Scattered impacts as a slow moving frontal system moves
through the region.
Mon-Wed...no sig wx.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Dangelo/Lambert
SHORT TERM...Lambert
LONG TERM...Dangelo/Lambert
AVIATION...Dangelo
Area Forecast Discussion
National Weather Service Grand Forks ND
951 AM CDT SAT SEP 17 2016
.UPDATE...
Issued at 943 AM CDT Sat Sep 17 2016
Only minor tweaks needed to sky cover needed for this update. The
RAP 1000-850 mb RH field has a very good handle on the cloud
cover across the northeast area of the forecast area. This cloud
deck is progged to slowly move eastward out of the area by
mid-afternoon. High temperatures in the mid 50s in this area still
look on track with low to mid 70s across the valley and westward
with sunshine.
UPDATE Issued at 632 AM CDT Sat Sep 17 2016
Minor adjustments made to sky cover as the back edge of overcast
area associated with departing upper low gradually advects
eastward. Expectation is area clear out by mid-afternoon. Did
change wx type to drizzle in limited area of remaining POPs in the
far northeast.
&&
.SHORT TERM...(Today and tonight)
Issued at 229 AM CDT Sat Sep 17 2016
Primary challenge for the rest of tonight and today will be
departure of some light rain showers over northwest Minnesota
associated with an upper low/trough over wrn Ontario/northern MN.
An upstream short wave ridge will move move over the Dakotas today
and bring dry weather to the eastern Dakotas and RRV, with some
lingering showers through the morning in the far northeast.
Associated surface ridge will be over the Devils Lake basin at 12Z
this morning and move into the eastern zones by 00Z Sunday,
setting up return flow across the eastern Dakotas tonight. This
will bring much warmer overnight lows to western zones tonight,
generally in the mid 50s...about 10 deg warmer than last night.
.LONG TERM...(Sunday through Friday)
Issued at 229 AM CDT Sat Sep 17 2016
The next concern will be winds in the western zones on Sunday as a
sfc trough associated with low pressure moving across central
Canada moves east. A well mixed atmosphere by mid-day Sunday, with
the GFS showing an adiabatic layer to around 800 mb in Devils
Lake (as well as a potent jet max moving across ND), will bring
breezy conditions west of the RRV. Adjusted winds upward from
superblend solution to get wind gusts around 25 to 35 mph Sun
afternoon, much more representative than the superblend solution.
The strong westerlies will bring daytime highs into the upper 70s
to low 80s on Sunday. Kept a chance for some light showers or
storms along the Canadian border as the sfc trough moves across
southern MB, however best chances for precip remain north of the
intl border in region of the left exit region of the upper jet.
Subsiding winds will allow Sun night lows to drop into the lower
50s and cooler but dry air on Monday will drop temps back into the
lower 70s, possibly the upper 60s across along the intl border.
The upper level pattern transitions to SW flow aloft mid-week.
Southwest flow aloft will bring a wet period to the area mid to
late week. One 500 mb short wave will move northeast from Wyoming
into the Dakotas with increasing precipitation chances Wednesday.
Then attention turns to the main 500 mb short wave and low which
will move into the western US Thu-Sat period. Timing issues noted
between the 00z ECMWF and 00z GFS with the ECMWF more progressive
and faster in bringing in significant rainfall to the area Friday
whereas the GFS over time digs the upper low farther south into
New Mexico. But even GFS model would bring up enough moisture for
a potential significant rainfall event but more later into next
weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 632 AM CDT Sat Sep 17 2016
Clear within and west of the Red River Valley. MVFR-IFR east of
the valley with TVF on the edge of low cloud deck. Currently clear
but may see some more IFR cigs drift in from the north before
entire deck shifts east late morning and erodes this afternoon.
BJI will be last to clear out in the early aftn.
&&
.FGF Watches/Warnings/Advisories...
ND...None.
MN...None.
&&
$$
UPDATE...Lee
SHORT TERM...Speicher
LONG TERM...Speicher/Riddle
AVIATION...Speicher
Area Forecast Discussion
National Weather Service Hastings NE
533 AM CDT SAT SEP 17 2016
.SHORT TERM...(Today and tonight)
Issued at 351 AM CDT Sat Sep 17 2016
Today will be absolutely beautiful with light winds, mostly clear
skies, and highs in the upper 70s across south central Nebraska
to near 80 over north central Kansas. A sfc high will track east
across Kansas resulting in the light wind, which will shift from
westerly to southerly as we head through the day.
The primary forecast concern and point of uncertainty will
surround the chance of thunderstorms this evening. Moisture will
be very limited with dewpoints currently in the 40s to around 50
and these will climb only slightly by this evening into the the
lower 50s. A subtle hardly noticeable vort max/upper trough will
slide east off the high plains this evening. The 07Z HRRR is the
most aggressive with developing showers and thunderstorms across
eastern Colorado by late afternoon, which then push east into our
western zones predominately after 7 pm. Several WRF models also
indicate that this high plains convection could make it at least
into our western zones this evening. Therefore, have added a
chance of thunderstorms to the forecast for this evening leaning
towards the lower superblend POPs.
There will be at least a marginal severe weather threat off to our
west late this afternoon, but given our feeble instability
(SBCAPE 500-1000 J/KG) and the late hour of arrival as we lose
diurnal heating it seems that any storms should be weakening as
they make it into our western forecast zones. Given decent deep
layer shear of 30 kts and at least some initial limited
instability, can not completely rule out an initial strong storm
or two in our far west from Gothenburg, down to Beaver City, and
south into Plainville, KS.
Weakening thunderstorms will likely die out before midnight and
currently seem unlikely to make it any further east than Highway
281, but this should be watched and updated in future forecasts.
.LONG TERM...(Sunday through Friday)
Issued at 351 AM CDT Sat Sep 17 2016
Dry conditions remain in the forecast to start of the long term
period on Sunday, and are expected to continue into the first part
of the upcoming work week. By Sunday morning, models are in pretty
good agreement showing zonal to low amplitude northwesterly flow
having developed in the upper levels, in the wake of a departing
shortwave trough axis. Overall, not expecting a lot of change in the
overall pattern as we go through Sunday and even into
Monday/Tuesday. Upper level flow remains zonal, with the CWA set up
between high pressure building over the southern Plains and a
disturbance sliding east across Canada. Models not showing much in
the way of waves affecting our area, thus the forecast remaining
dry. At the surface, west-southwesterly winds are expected to be in
place during the day on Sunday, with high pressure over much of the
southeastern CONUS and a frontal boundary working its way in from
the west. This boundary looks to push through the area late Sunday
night into Monday, but not much in the way of impact is expected
outside of a switch to more northwesterly winds and lower dewpoints.
High pressure behind this boundary builds into the area for later
Monday/Monday night, before sliding off to the east, allowing for
southerly return flow for Tuesday. Forecast highs for Sun-Tues
remain in the 80s.
Looking to the mid-later portions of the week, there is more
uncertainty in the forecast, as precipitation chances make a return.
The upper level pattern across the Central Plains transitions to
southwesterly flow by Wednesday morning, as the ridge axis
associated with that southern Plains high gets pushed east of the
area by low pressure/troughing moving onto the West Coast. A more
organized upper level low pressure system is expected to start
working its way east into the Rockies through the Wed-Fri period,
but confidence isn`t the highest. There are notable differences
between models with the timing/track of this system, with the 00Z
ECMWF quicker/further north than the 00Z GFS. Hard to go higher than
20-30% chances at this point, lot of details with any lead
shortwaves are yet to be determined.
&&
.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Sunday morning)
Issued at 525 AM CDT Sat Sep 17 2016
VFR conditions will persist throughout the TAF valid period. The
wind will be light and shift from westerly to south southwest through
the period as an area of sfc high pressure slides off to the east.
Low level wind shear will increase tonight, but should be below
the threshold for including it in the TAF.
&&
.GID Watches/Warnings/Advisories...
NE...None.
KS...None.
&&
$$
SHORT TERM...Wesely
LONG TERM...ADP
AVIATION...Wesely
Area Forecast Discussion
National Weather Service Wilmington OH
1046 AM EDT Sat Sep 17 2016
.SYNOPSIS...
A moist airmass will remain in place ahead of a cold front, resulting
in periods of showers and thunderstorms today and tonight. The
front will push through the region Sunday bringing an end to the
thunderstorms from northwest to southeast. High pressure will
bring a dry and sunny day on Monday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Southwest flow at the surface and aloft continues ahead of a cold
front and upper trough across the Midwest. Ahead of these
features, a low level jet is evident over the Ohio Valley...on
the order of around 40 kt. Low level jet will help pump moisture
ahead of the front and also help to produce a decent coverage of
showers as is already depicted on radar.
Expect thunderstorms to enter the mix as well later today,
however overall instability is forecast to be on the weak side.
Best chance for higher instability (several hundred J/kg CAPE)
for thunderstorms looks to be along/east of Interstate 71.
Assuming some CAPE, this combined with the low level jet may allow
a few thunderstorms to produce strong to locally damaging wind
gusts. High moisture may also lead to heavy downpours although the
progressive movement of convection should limit the overall flash
flood risk. Still, heavy rainfall could produce localized minor
flooding.
Re-worked pops/wx based on latest radar trends (showers just now
entering far western CWA) and based on the latest HRRR which seems
a little faster than recent runs of the NAM or GFS. Also re-
worked temperatures, with highs in the mid to upper 70s through
the Whitewater/Miami Valleys and mid 80s toward south central
Ohio/northeast Kentucky.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
Convection gets hung up southeast of I-71 tonight as cdfnt works
into the region. Overall expect the coverage to diminish, but
there will be lingering chance overnight. Lows should drop back
into the mid 60s.
On Sunday, a secondary H5 s/w swings across the Ohio Valley. This
will help keep a chance of pcpn along and se of I-71. Highs should
only make the upper 70s. Finally as the upper trof swings through
Sunday night the pcpn chances will come to an end. Cooler/drier
air will begin to filter in and lows will range from about 55 to
60 degrees.
With high pressure across the region on Monday, expect the skies
to be mostly sunny. The sunshine should be enuf to push highs back
into the lower 80s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
High confidence that this period will be above normal in
temperatures and largely quiet in terms of weather. Ridging over the
southern US will expand and intensify as strong negative height
anomalies dig through southern Canada. A weak cold front will
slide through the Great Lakes on Tuesday. This feature will be
losing amplitude with time and thus low level forcing not overly
strong and mid level forcing is peeling away to the northeast the
shortwave trough deamplifies moving through/atop large scale
ridging. Did not introduce rain chances in this forecast but small
chances may need to be added in future forecasts. Wednesday and
Thursday largely looking dry as ridging continues to surge north -
and muggy air once again returns to the region by the end of week.
Questions begin to arise this late in the forecast on whether
shortwaves will track close enough to the area for rain chances
primarily Thurs night/Friday. Quite of bit of uncertainty and thus
forecast left largely dry save for some small rain chances in west
central Ohio closest to stronger flow/moisture advection.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
A shield of SHRA/TS will continue to push NE across IN and
northern OH through the AM. A few spotty lingering showers will be
possible through 15z, but expect terminals to be mostly dry
through late morning. Scattered SHRA/TS across central IN will
develop and push east toward western terminals by 15-18z. Activity
should push east of TAF sites by 00z Sunday. Brief MVFR VSBYs and
CIGs will be possible in heaviest pcpn.
Light southerly winds will increase in the late AM/early PM time
frame ahead of convection/pcpn as a weak sfc low tracks north of
the area. Winds may gust to 15-20kts during the afternoon, with
additional storm-driven gusts possible.
Expect scattered SHRA/TS to be mostly E of terminals by 00z, with
some spotty lingering activity still possible through 03z,
especially for eastern sites of KCMH and KLCK. The main concern after
03z will be the potential for MVFR CIGs and VSBYs area- wide as
model soundings show that low levels may become nearly saturated.
There exists the potential that CIGs and VSBYs may go below MVFR
after 06z Sunday, but confidence on timing or exact location
precludes inclusion in the TAFs at this time.
OUTLOOK...Thunderstorms are possible Sunday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...AR
NEAR TERM...BPP
SHORT TERM...Sites
LONG TERM...Binau
AVIATION...KC
Area Forecast Discussion
National Weather Service Indianapolis IN
1054 AM EDT SAT SEP 17 2016
.UPDATE...
The Aviation Section has been updated below.
&&
.SYNOPSIS...
Issued at 318 AM EDT Sat Sep 17 2016
A cold front will move through the area today, bringing showers and
thunderstorms. High pressure will briefly build in for Sunday into
Monday, but another front could bring some rain Monday night into
Tuesday. Another frontal system could bring more rain late in the
week. Temperatures will remain above average.
&&
.NEAR TERM /This afternoon/...
Issued at 926 AM EDT Sat Sep 17 2016
Surface Analysis late this morning shows a trough of low pressure
over Illinois and Lake Michigan. Water vapor shows a plume of
tropical moisture streaming across the lower Mississippi River
valley across Indiana to the eastern Great Lakes. Good subsidence
and drying was seen in the wake of the plume...across western
Illinois. Radar shows the best organized precip echos across
central Indiana...moving quickly east.
HRRR suggests the current band of precip will be the best threat
for the rest of the day. This area of precip should propagate east
of Indiana by early afternoon. HRRR suggests a few pop up type
showers and storms will be possible along and near the trough
passages this afternoon. Forecast sounding continue to keeps
decent moisture available through the afternoon with convective
temperatures in the middle 70s. Thus an isolated TSRA/shra
development cannot be ruled out...chances for precip are expected
to continue to diminish as the afternoon progresses and subsidence and
drying wets of Indiana continues to build to the east. With plenty
of clouds and ongoing rain expected today...trended high
temperatures cooler...closer to the 3 hourly mavmos.
&&
.SHORT TERM.../Tonight through Monday night/
Issued at 318 AM EDT Sat Sep 17 2016
Focus is on rain chances through the period. For most of the period,
models are close enough that a blend was used.
The cold front will still be passing through the area this evening,
so kept some low PoPs in during the evening, lingering into the
early overnight far south.
Surface high pressure will build in on Sunday, even as an upper
trough moves across aloft. With the high at the surface along with
limited moisture, kept a dry forecast Sunday.
Dry conditions will continue through the day Monday with the high in
control.
A cold front will move into the northern forecast area Monday night.
Moisture is limited and upper support weak. Thus only went some
slight chance PoPs north.
Generally stayed with a model blend for temperatures through the
period.
&&
.LONG TERM /Tuesday through Friday/...
Issued at 318 AM EDT Sat Sep 17 2016
A weak cold front may produce an isolated thundershower central and
south early Tuesday before it moves out of the area. Otherwise...
high pressure will bring dry weather rest of tuesday through Thursday
as it moves east across the area.
Models diverge some late next week as the GFS indicates a cold
front may move as far south as northern Indiana by Friday...while
the EURO with a stronger upper ridge across our region keeps this
front farther north. If the EURO is right it will be dry and quite
warm late next week. But given that the previous forecast already
has a slight chance of storms north and central next Friday...will
continue this slight chance for now.
Highs will be in the lower 80s next Tuesday and middle 80s or warmer
late next week. Lows will be in the upper 50s to near 60 Tuesday
night and in the 60s rest of the long term. Tweaked high
temperatures warmer late next week. Otherwise...stayed close to
super blend temperatures.
&&
.AVIATION /Discussion for 171500Z TAF Issuance/...
Issued at 1054 AM EDT Sat Sep 17 2016
For the update, removed any thunder mention for the day. Relevant
parts of previous discussion follow...
MVFR flight conditions or lower at times this morning. Then mostly
VFR until late tonight with IFR fog possible towards Sunday morning.
Could see periods of MVFR or IFR ceilings through early afternoon as
cold front moves across the region. Model soundings indicate
generally VFR ceilings of 4 thousand feet or higher from mid
afternoon on with clouds scattering out some areas tonight.
Could see areas of IFR Fog late tonight due to wet ground and
radiational cooling.
Winds will become southwest up to 10 knots by midday and light
tonight.
&&
.IND Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...PUMA
SHORT TERM...50
LONG TERM....JH
AVIATION...JH/CP
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1050 AM EDT Sat Sep 17 2016
.UPDATE...
Issued at 1050 AM EDT SAT SEP 17 2016
14Z sfc analysis shows high pressure off to the east of Kentucky
while a cold front and low pressure is approaching from the west.
Ahead of this front, an area of weakening showers are slowly
pressing eastward. For eastern Kentucky any potential for morning
convection has shifted off to the northeast with skies mostly
clear in the warm sector ahead of the cold front. The latest near
term models, including the HRRR, show pcpn holding off for our
CWA until at least late afternoon - awaiting the better support
associated with the front and mid level trough. Plenty of morning
sunshine should help send current temperatures in the mid 70s up
into the mid to upper 80s yet again. This will combine with
dewpoints in the mid 60s to generate a good amount of instability
by the time the front gets here. In addition, veering winds aloft
will support the storms becoming organized along and ahead of the
boundary. As a result, any of the convection that does develop
toward evening could become strong with gusty winds and heavy
rains - climbing PWS and slow boundary - the main threat. With the
morning clearing, winds have been able to mix down effectively
yielding southwest ones around 10 mph at the sfc with gust to
15-20 mph or so. Have updated the forecast through the afternoon
with the above in mind. These grids have been sent to the NDFD and
web servers. A freshened set of zones were also issued.
UPDATE Issued at 620 AM EDT SAT SEP 17 2016
Opted to slow down the arrival of precipitation a bit more today
based on latest hi-res model guidance. Many of the models have a
very slow movement to the east today and thus, a slower solution
seems reasonable. The HRRR seems to be the most progressive with
spreading things east, but based on the initialization, it doesn`t
seem to be matching current trends. Thus, opting to follow a
solution closer to the NSSL WRF/ARW/NMM.
&&
.SHORT TERM...(Today through Sunday)
Issued at 304 AM EDT SAT SEP 17 2016
A vort max passing across the region this morning has kicked off
some very isolated showers as its worked northward across the
area. This activity will continue to lift northward into northeast
Kentucky over the next few hours before exiting to the north.
Meanwhile...a cold front continues to slowly move eastward and
is currently aligned along the Ohio river bordering Illinois and
Kentucky with the front stretching northward across Indiana. This
front will make very little progress to the east today. Subsidence
ahead of the approaching boundary may keep eastern Kentucky dry
for much of the upcoming day. All the hi-res models keep
precipitation out of eastern Kentucky until at least after
21z...and many don`t have anything until after 00z. Thus, went
with a mainly dry forecast, but did bring some low pops into our
western zones very late in the day as the front nears. Main rain
chances will come tonight into Sunday morning as the front crosses
eastern Kentucky. Models continue to show plenty of moisture and
lift with the front and thus corresponding pops are quite high.
Given this setup, have opted to go with categorical pops as most
of the area will see measurable rain with this front. Front will
hang up over the area on Sunday, leading to rain chances through
the day. The front will finally start to push east late in the
day, with rain chances diminishing in the evening. PW`s will
approach 1.90 early Sunday, so some locally heavy rainfall will be
possible. However, instability remains weak through Sunday, so we
may not be able to realize the heavier rainfall potential if
instability does not materialize. Regardless, should see some much
needed rainfall.
Stayed above guidance on highs today as the delayed onset of rain
will allow the area to heat up once again today into the mid to
upper 80s. A few 90 degree readings are possible again today.
Stayed close to guidance on lows tonight with precipitation and
clouds across the area. Clouds and precipitation will hold for
Sunday, so have undercut guidance on the highs with temperatures
failing to make 80.
.LONG TERM...(Sunday night through Friday)
Issued at 430 AM EDT SAT SEP 17 2016
A poorly defined cold front will be in our area as the period
starts, and an upper level trough will be approaching from the
west. The additional upper level support arriving will be enough
to help the front make the jump across the Appalachians on Sunday
night. Before this happens, there will still be a potential for
showers and thunderstorms in the evening, mainly in the southeast
part of the forecast area. Drier air associated with weak ridging
will arrive from the west during the night. The surface portion of
this ridge breaks down early in the week, while an upper level
high remains anchored over the south central conus. A cold front
trailing from a large storm system rolling across Canada will drop
south, until stalling and dissolving in our area as it reaches the
southern edge of the prevailing westerlies aloft and encounters
the upper level high at mid week. The front will be moisture
starved and is not expected to generate any weather of
significance. The upper level high is then forecast to
build/transition to the southeast CONUS as surface high pressure
passes by to our northeast late in the week. This scenario should
keep our weather dry. Each cold front will try to bring a minor
influx of drier air, which will allow for seasonably cool early
morning temperatures, while sunshine results in warm afternoon
readings.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 620 AM EDT SAT SEP 17 2016
Expect mainly VFR conditions to prevail through this evening.
Winds will increase from the southwest today ahead of an
approaching cold front. This front will cross eastern Kentucky
tonight, with a round of showers and perhaps a few storms
expected. This could bring some temporary reductions in ceilings
and visibilities. As the front pushes across the area Sunday, we
could be looking at period of MVFR (and perhaps some IFR)
conditions immediately behind the front. With the front expected
to move very slowly, the restrictions to ceilings may persist
through much of Sunday, keeping conditions MVFR or worse.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
Area Forecast Discussion
National Weather Service North Platte NE
605 AM CDT SAT SEP 17 2016
.SHORT TERM...(Today and tonight)
Issued at 355 AM CDT Sat Sep 17 2016
The main concerns in the short term period centers around rain
showers/thunderstorms chances and the potential for strong and/or
severe thunderstorms. At the present time satellite imagery shows
clear skies and no significant weather occurring across the
forecast area. Warmer conditions are expected today, with highs
forecast in the lower 80s, about three to eight degrees above
normal. Above normal lows are then expected overnight, mid 40s in
the far western portion of the forecast area to low to mid 50s in
north central NE.
Weak 500 hPa height rises will be occurring at the start of the
period over western and north central NE as a broad 500 hPa
trough will be over the MN Arrowhead Region and far Upper Great
Lakes. The upper level trough will deamplify over the next 24
hours as it lifts eastward into the extreme eastern portion of
Ontario. In the meantime, a short wave trough is anticipated to
move east across south central WY to southwest NE to north
central KS by late this evening. This disturbance is expected to
provide weak large scale ascent and support convective
development as mid-level lapse rates steepen over northeast CO
and the NE Panhandle into western NE this afternoon and evening.
Meanwhile, broad surface high pressure currently over the Central
Plains will move eastward today and a weak lee side trough will
develop and deepen near the Front Range. Current thinking is that
convective development will be focused in this trough. Wherein
modest instability and sufficient moisture will combine with 0-6
km bulk shear generally about 20-35 kts that will be conducive
for organized multicells. Of which, moisture looks to be the
primary limiting factor and this could be attributable to the
amount of moisture being returned northward into the forecast
area today. Development is expected to move from northeast CO
into the forecast area and/or occur in southwest NE early-mid
evening with isolated to scattered coverage expected. Hi-res
deterministic guidance, HRRR and flavors of WRF, were in decent
agreement at the present time with forecast development shown
21-00Z today. Confidence in development is further increased
based on SPC SSEO output from the 00Z cycle today wherein a
strong signal appears present over southwest NE and northeast CO
for convection. The main risks will be strong winds and hail. Of
note, the latest SPC Day 1 Outlook has the southwest quad of the
forecast area in a marginal risk area, which seems appropriate if
storms can develop given aforementioned vertical wind shear.
Ultimately, a strong/severe storm or two could be possible today,
and cannot be ruled out. Any development is expected to taper
off/diminish in the late evening or move southeast out of the
area. After which, quiet conditions are expected.
.LONG TERM...(Sunday through Friday)
Issued at 355 AM CDT Sat Sep 17 2016
Generally upper level zonal flow overhead with a broad ridge
across the southern plains to begin the week. Thermal ridge Sunday
across the area with highs into the 80s. A weak cold front will
enter the picture on Monday. Models in disagreement on timing the
front through the southern part of the CWA. Expect the northern
part of the CWA to see about 5 degrees or so drop in temps from
Sunday, however less confidence for the area along and south of
I80. Forecast is conservative across the south and will continue
temps only a couple of degrees cooler, but would not be surprised
to see highs a degree or two warmer due to compressional heating
ahead of the front. Little moisture to work with and temps aloft
stay fairly warm for mid September and expect the passage of the
front to be dry with only some passing clouds. Thermal ridge
quickly rebuilds for Tuesday with temps expected to go back up.
Next upper level trough and sfc frontal passage is expected Wed.
Ahead of the front southerly winds will usher in some sfc moisture
which will aid in keeping lows very mild Wed morning, only falling
into the mid 50s and lower 60s. The return of sfc moisture will
result in a chance for precip with the passage of the front,
mainly in the east on Wed.
The trough will continue to push to the north with another trough
to dig to the west. The ridge will get shoved east with more SW
flow aloft. This will return some upper level moisture and bring a
better chance precip with several disturbances. Pops are low at
this time as model differences exist with waves. Expect at least
more mid and high clouds. Pending cloud cover which could keep
temps lower during the day, mos guidance still keeps afternoon
highs fairly close to seasonal averages or warmer.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 600 AM CDT Sat Sep 17 2016
VFR category prevails across western and north central NE at the
present time and VFR are expected to continue through the
aviation forecast time period. Clouds are expected to increase
across southwest Nebraska in the afternoon with broken ceilings
possible, wherein cloud bases around 7 kft to 10 kft are
expected. Isolated to scattered thunderstorms are possible across
southwest NE in the afternoon and evening, however, best chances
are expected to be west and south of KLBF. Therefore
showers/thunderstorms were not included in the KLBF TAF at this
time given low confidence and expected coverage. Winds will be
southwest and peak between 10 and 15 kts. Chances for
precipitation then diminish in the mid to late evening.
&&
.LBF Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...ET
LONG TERM...Masek
AVIATION...ET
Area Forecast Discussion
National Weather Service Lubbock TX
610 AM CDT SAT SEP 17 2016
.AVIATION...
LBB will start the morning with TSRA close and on the terminal
while PVW and CDS are under VFR conditions. Conditions at LBB
should improve by 12Z and remain VFR into the early afternoon at
least. TSRA will be possible at all three terminals this afternoon
and evening, however coverage and timing are highly uncertain. Due
to high uncertainty TSRA will be kept out of this TAF cycle. MVFR
CIGS will be possible towards the end of this TAF cycle tomorrow
morning.
&&
.PREV DISCUSSION... /issued 303 AM CDT SAT SEP 17 2016/
SHORT TERM...
Thunderstorms have started to develop along a weak surface
boundary/front across our southwestern zones. The boundary is hardly
discernible using surface obs as winds are light and vary variable,
but the boundary does show up on radar. This convective development
coincides with an upper level jet streak moving into the FA as shown
by WV imagery and a LLJ that has developed over the past few hours.
This activity is being pushed east northeastward by the mid and
upper level flow. The only model to pick up on this activity well is
the 00Z run of the TTU-WRF and keeps this activity going till after
sunrise before dissipating across our northeastern counties. The 06Z
run of the HRRR also shows this activity, but has it developed
further north than it currently is and pushes the convection
southeastward instead of northeastward and dissipated the convection
fairly quickly. Given the persistent and even strengthening LLJ, it
can be believed that convection could be sustained at least for the
next several hours.
Now for the big question: what will happen from later this morning
into tonight? Models have each given their thoughts on the matter,
and each thought is different from the other models. Given that the
higher res mesoscale models have performed the best recently, they
will be weighted more heavily in the forecast. An upper level
shortwave currently over northeastern UT/southwestern WY should
develop a lee trof by the late morning in CO, during which time
convection is progged to develop over the higher terrain of NM. The
terrain induced convection has the potential to push eastward into
the FA possibly merging with convection along the lee trof to form a
QLCS. The QLCS may push into our northern zones of the FA later this
evening , but current guidance keeps it northward in the TX and OK
Panhandles. For now chance PoPs for this evening will remain
unchanged due to the uncertainty of where the QLCS will go.
Aldrich
LONG TERM...
The long term will serve up warm and dry weather as a change in
the upper pattern takes place early in the period. Upper level
ridging will build over the region Sunday with the center over or
near the region through Tuesday. Wednesday will see the ridge
shift to the east as an upper trough develops over the western
CONUS. It is looking more and more like energy from this trough
will remain well west of the forecast area, a trend noted in the
last several model runs. Really cannot pick out a period where
thunderstorm chances would be high enough to include in the
forecast, and will thus remove mention through Friday. Have again
trended temperatures toward MOS for Monday and Tuesday, slightly
higher than the model blend. Otherwise, the blend looks fine.
&&
.LUB Watches/Warnings/Advisories...
None.
&&
$$
51
Area Forecast Discussion
National Weather Service Paducah KY
657 AM CDT SAT SEP 17 2016
.SHORT TERM...(Today through Monday night)
Issued at 344 AM CDT Sat Sep 17 2016
Current radar trends indicate showers and isolated thunderstorms
moving across the region faster than previously forecast. The
latest HRRR and ECMWF seem to have a decent handle on the timing.
This lends itself to a quicker end to precip across the region,
with far western portions of the PAH forecast area precipitation
free by mid day, and all but far eastern portions dry by late
afternoon. Adjusted precipitation chances to reflect this trend,
and removed precipitation chances completely for late tonight and
Sunday. Temperatures will cool down just a little behind the cold
front to near seasonal readings.
High pressure will shift across our region for Sunday night into
Monday night. This will keep our region dry, and winds will shift
back to the south. Temperatures will warm back up to above
seasonal readings with highs Monday in the middle to upper 80s,
and lows Monday night middle to upper 60s.
.LONG TERM...(Tuesday through Friday)
Issued at 344 AM CDT Sat Sep 17 2016
Above average confidence through most of the period, then average
to below average at the very end due to model inconsistencies.
Very little to discuss and very few changes synoptically in the long
term period, especially if the ECMWF pans out. High pressure at the
surface and ridging aloft is forecast through the long term period
producing dry, warm, and humid conditions.
On Friday the GFS weakens and suppresses the upper ridge southward
allowing a back door cold front to sag into the far northern and
northeastern sections of our CWA and cranks out a bit of QPF in the
process. During the same time frame the ECMWF keeps the ridge
stronger and keeps all frontal boundaries and precipitation chances
well to our north. Will go with the more consistent ECMWF solution
for now and keep it dry every period.
Temperatures will remain at or above normal through the period.
&&
.AVIATION...
Issued at 657 AM CDT Sat Sep 17 2016
MVFR to IFR cigs with VFR vsbys expected through the day ahead of
a cold front. Showers at KEVV/KOWB will move east of sites by 15z.
Isolated showers and storms possible through the day but chances
not high enough to include in TAFs. South to southwest winds at 3
to 7 kts will become northwest around 18z at KCGI/KOWB, and
between 22z-02z at KEVV/KOWB. Conditions will become VFR this
evening, with MVFR vsbys possible after 08z.
&&
.PAH Watches/Warnings/Advisories...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...RST
LONG TERM...JP
AVIATION...RST
Area Forecast Discussion
National Weather Service Charleston WV
1203 PM EDT SAT SEP 17 2016
.SYNOPSIS...
A cold front moves slowly across the area tonight and
Sunday...with widespread showers and scattered thunderstorms. High
pressure early next week brings only slightly cooler weather.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1100 AM Saturday...
Per hi res models and satellite/radar trends...have adjusted pops
remainder of today to only slight chance of an afternoon shower
or storm. Have also lowered sky cover somewhat with brief mid
level dry intrusion ahead of approaching front tonight.
As of 638 AM Saturday...
Made a whole bunch of edits to the POPs based on current radar
trends...the HRRR...and the RAP models. In the end...line of
showers with isolated storms will move east slowly this
morning with the boundary...dissipate into the afternoon with
only low chances across the area into tonight...and redevelop
later tonight as the cold front approaches. No POPs below 15 for
the near term however.
As of 255 AM Saturday...
Showers developing along the warm front this morning...expected
to make a slow drift eastward through the remainder of the morning
hours. Coverage should gradually increase during this time frame
as well. Once the warm front exits...a lull in the activity is
expected...largely until the cold front pushes into the middle
Ohio Valley. CWA will not be devoid of POPs in this transition
period.
In the meantime...southwest flow aloft will be on the
increase...with upper level support aiding in the development of
the convection later today in the far northwestern zones.
To the northwest...there will be a significant increase in the
low level flow with a 45kt 850mb jet setting up over northern
Ohio. With that...SPC includes the southeast Ohio counties in a
marginal risk of severe weather today for wind. This is ahead of
an upper trough embedded within the aforementioned southwest flow
aloft. Towards the 12Z Sunday time frame...expecting an increase
in the low level frontogenesis into the Tug Fork Valley...so
ramped up POPs sharply towards the transition to the short term
forecast.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 345 AM Saturday...
A good soaking rain is on tap for Sunday. Weak cold front and
associated shortwave will slowly press through the region.
Moisture advection in southwesterly flow will push PWATs near or
slightly above 1.75 inches. This is about 2 standard deviations
above normal...and although instability and forcing will be weak
there should at least be enough lift to develop some embedded
thunderstorms. Not thinking we will see flash flooding issues
since we have been very dry the past several weeks. However...if
a few storms could train over the same area then some minor flash
flooding could be possible and as such...WPC has highlighted our
area for a marginal risk for excessive rainfall.
High pressure and cooler air moves in for Monday...but with upper
trough overhead and northwesterly flow giving us some orographic
accent...there should be enough to kick off some isolated showers
in the Eastern Mountains. Other than that skies will clear Monday
night and make for a cool night where it may actually feel a bit
like Fall. Radiational valley fog will likely be widespread
overnight Monday and into Tuesday morning.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 150 PM Friday...
The long term is overall a quiet period, starting out with high
pressure in control. Both GFS and ECMWF show a weakening front
approaching Tuesday, but with dry air in place neither are showing
much in the way of QPF. Kept the forecast dry. High pressure settles
back in to end the work week.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
As of 11 AM Saturday...
Til 00Z... Warm front with scattered showers quickly exiting area
to the north at 15Z. Thereafter...a brief mid level dry intrusion
will limit afternoon convection to isolated...except over
southeast Ohio where a band of widespread showers and a few
thunderstorms will arrive well ahead of a cold front after 22Z.
Thus...have removed mention of showers and storms from major TAF
sites this period. Maintain VFR sct-bkn 4500-8000 foot AGL clouds
this afternoon...except MVFR where widespread showers arrive over
portions of Southeast Ohio late this afternoon and evening. South
winds 6 to 12 kts.
After 00Z...
The band of widespread showers and scattered thunderstorms well ahead
of a cold front...will slowly spread eastward across the area
with a slow moving strong upper level disturbance...reaching a
CKB-CRW-JKL line 10-12z. The cold front itself will lag far
behind the advancing so light south winds around 5 kts will can be
expected. VFR ceilings will lower to IFR in rain and fog as the
band of showers and storms arrive. Thus...PKB and HTS will lower
to IFR by 07Z...CKB and CRW by 12z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Timing of band of convection tonight may
be slower than currently forecast.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
EDT 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
CRW CONSISTENCY M M H H H H H H H H H M
HTS CONSISTENCY H H H H H H H H H H H M
BKW CONSISTENCY H M M H H H H H H H H M
EKN CONSISTENCY H H M L M H H H H M M M
PKB CONSISTENCY M M H H H H H H H H H M
CKB CONSISTENCY H M M L M H H H H M M M
AFTER 12Z SUNDAY... IFR possible in showers/storms with cold
front this weekend.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...JMV/MPK/26
NEAR TERM...26
SHORT TERM...MPK
LONG TERM...MZ
AVIATION...JMV/26
Area Forecast Discussion
National Weather Service Blacksburg VA
958 AM EDT Sat Sep 17 2016
.SYNOPSIS...
High pressure, both at the surface and aloft, will weaken and
shift east of the region through Sunday. An upper trough and
associated cold front will move into the region Sunday, taking
until Monday to move through the Piedmont. High pressure will
build over the region by Tuesday and linger through the end of
next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 950 AM EDT Saturday...
Models are backing off of mountain showers through this afternoon.
Morning showers over the Ohio Valley are tracking to the
northwest and there is no evidence that any will develop in their
wake. We will keep a small chance across SE WV late this afternoon
for the possibly of scattered showers forming from any outflow
boundaries during peak heating. The best chance for widespread
showers to enter the mountains will come Sunday morning as a cold
front approaches the area.
As of 400 AM EDT Saturday...
High pressure off the northern Mid-Atlantic coast will shift east
in response to an upstream trough/cold front approaching from the
Midwest. However, it will not do so soon enough to prevent another
mostly cloudy, relatively cool/mild day compared to most days this
month, which have been well above normal. The low clouds are
expected to erode across the Piedmont and west of the Alleghany
front by afternoon and in most areas by evening as the upper
trough/front continue to move into the region from the west.
However, this will not be soon enough to allow temperatures to
warm yet back to the pre-wedge levels we saw much of this past
week.
Precipitation is expected to be scarce again today. Most synoptic
and short-range models indicate that the best and initial dynamics
associated with the upper trough will move northeast toward the
Great Lakes/eastern OH valley. Showers and a few thunderstorms
will likely approach the northwest border of the CWA late in the
afternoon/evening but probably stop short of spreading into much,
if any, of the RNK CWA. The HRRR and NCEP WRF show little to no
precipitation spreading into the RNK CWA this afternoon/evening.
The first wave will go by overnight leaving us with just mid/high
clouds and little precipitation. Therefore, have confined pops to
slight chance/low chance along the western border to near zero
along and east of the Blue Ridge. Mentionable pops have generally
been confined to just the western most tier of counties, with the
highest pops from KBLF to west of KLWB.
As noted above, an increase in temperatures is expected today, but
should stop short of the 10F above normal readings we have seen
most days this month. Max temperatures today will be entirely
dependent on when the low clouds diminish. If this occurs late
morning, as opposed to the afternoon, advertised readings may be
too cool. Have leaned toward the cooler GFS gridded temperatures
as it seem to have the best depiction of the wedge air mass.
Minimum temperatures Sunday morning will be well above normal,
mostly in the 60s. We should be seeing lows in the 40s and 50s by
now!
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
As of 145 AM EDT Saturday...
The cold front that is expected to remain to our west today and
tonight, will make gradual headway eastward into and through the
region Sunday into Sunday night. Anticipate an increase in the
coverage of showers from west to east as the day progresses,
especially by the afternoon hours. Chances will be greatest in the
east during the evening and overnight hours. Model forecast
instability factors are not substantial, nor are they on the low
side. The forecast will reflect a slight chance for thunderstorms by
mid-day Sunday continuing only into the early Sunday evening hours.
The probability of showers will be in the likely category in areas
closest to the front.
By Monday morning, the front will have just exited, or be on the far
eastern edge of the forecast area. Slow progression eastward is
still forecast for this feature. It is expected to still be in close
enough proximity to allow for isolated to scattered showers across
eastern parts of the area. Forecast instability factors are more
impressive for thunderstorm development during the peak heating of
the day, especially the far eastern parts of the area by the late
afternoon. Other showers are forecast across the preferred upslope
regions of southeast West Virginia during the morning hours thanks
to residual low level moisture and an increasing upslope, northwest
flow in that region in the wake of the cold front.
Surface high pressure is expected to build across the Ohio Valley By
Monday night, and take on a west-east orientation with its axis
reaching the Delmarva peninsula by Tuesday night. Aloft, an upper
ridge is also expected to develop over the Tennessee and Ohio
Valleys. As geopotential heights build across the region, so too
will 850 mb temperatures.
Late night and early morning fog will be common through the period,
especially Sunday night and Monday night.
Despite the passage of a cold front, temperatures during this
portion of the forecast will continue to remain above normal for
this time of the year by five to ten degrees.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 PM EDT Friday...
High pressure, both surface and aloft, is expected to dominate
the region much of this period. An upper level trough is progged
to become a closed low over the southeastern states as it begins
to interact with Tropical Storm Julia, drifting west again back
toward the southeast U.S. coast. An upper level ridge will build
east from the Gulf States Wednesday and center itself over the
Carolinas by next weekend. This ridge could take Julia westward
across Florida and into the Gulf of Mexico. For the immediate
area, this ridge will bring several days of warmer than normal
temperatures and little chances for rain.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
As of 735 AM EDT Saturday...
Weak wedge continues to hold across the area with widespread MVFR
to high end IFR cigs in place across much of the CWA at this time.
Expect ceilings to improve to MVFR in the 14Z-16Z time frame, then
to VFR during in the 17Z-18Z time frame as the wedge erodes from
both the west and east ends. Do not expect the wedge to hold as
well as it did Friday as upstream trough/front encroaches on the
departing wedge. Latest model runs, including HRRR and NCEP WRF, show
little in the way of meaningful precipitation reaching the CWA
today, so have not advertised. Feel that this will remain west to
northwest of the CWA, closer to the upper dynamics with an
approaching short wave and not be able to penetrate the weakening
wedge air mass to any appreciable degree, at least not at the TAF
sites. Perhaps in Smyth/Tazewell area, so may need to watch KBLF
late in the day.
With the wedge gone overnight/Sunday morning, do not expect a
repeat of the low clouds and MVFR-IFR cigs. However, mid/high
clouds will spread into the region from upstream. These should be
mostly VFR cigs. The problem Sunday morning evolves east of the
Alleghany front, where cloud cover may be too sparse much of the
night to prevent ground fog development. Confidence is not high
enough to advertise IFR-LIFR conditions in fog Sunday morning, but
this is a possibility at KBCB and KLYH for sure. Showers and any
thunderstorms will hold off until well after this valid TAF
period. Winds will remain mostly E-SE through the period at
speeds of 5-7kts with low end gusts possible at KBLF until late
afternoon, especially this morning, however.
Medium confidence in cigs through the TAF valid period.
Medium to high confidence in vsbys through the TAF valid period.
Medium to high confidence in wind speed/direction through the TAF
valid period.
Extended aviation discussion...
Approaching cold front will move into the region Sunday, but take
until Monday to move completely east of the CWA. Wedge front
dissipates. Sub-VFR cigs will be possible Sunday as a result of
increasing showers and isold thunderstorms during the afternoon,
with patchy fog/low clouds in the morning.
High pressure will build back into the region early in the week,
so after the front exits the area Monday morning, expect most VFR
conditions for several days until late week. The exception will be
late night/early morning fog/low clouds, more likely toward the
end of the week as moisture begins to return around the departing
surface high.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB/RCS
SHORT TERM...DS
LONG TERM...RCS
AVIATION...RAB
Area Forecast Discussion
National Weather Service SAN ANGELO TX
613 AM CDT SAT SEP 17 2016
.AVIATION...
/12Z TAFS/
VFR conditions should prevail across West Central Texas terminals
through the period. However, scattered showers and thunderstorms
will again be possible. Latest model data suggests the San Angelo
(KSJT) has the best chances from seeing one of these storms,
although the odds remain low. Given the low odds, will not insert
in the forecast at this point but continue to monitor and see if
the model trend continues. Winds will remain light, but mainly out
of the south and southeast.
&&
.PREV DISCUSSION... /issued 325 AM CDT SAT SEP 17 2016/
SHORT TERM...
(Today and Tonight)
Bulk of the evening convection has now dissipated across West
Central Texas early this morning. Models have struggled to handle
the convection over the last few days across West Central Texas,
with the HRRR handling the short term better than the other models.
Thus, will lean towards its solution as a first guess to start the
forecast, with scattered convection developing late this afternoon
across the western portions of the area, mainly west of an Abilene
to San Angelo line. Like has happened the last few days, expect this
convection to spread east across the area into the evening hours.
As for temperatures, will not deviate much from what we have seen
the last few days. Readings have managed to climb into the upper 80s
and lower 90s across the area, and should be in the same range
today.
LONG TERM...
(Sunday through Friday)
On Sunday, an upper level ridge will be centered across South
Texas/northern Mexico. A subtle upper level shortwave trough is
forecast to swing across North Texas which may aid in the
development of scattered showers and thunderstorms Sunday afternoon,
mainly across the eastern half of the forecast area. Any shower and
thunderstorm activity should dissipate by early evening. High
temperatures will be well above seasonal normals, in the low to mid
90s.
An upper level ridge will dominate the weather across West Central
Texas through much of the upcoming work week. Generally dry
conditions are expected along with above normal temperatures. Highs
through the first part of the work week will be in the low to mid
90s, with overnight lows in the upper 60s to lower 70s. The center
of the upper level ridge is then forecast to shift toward the South
Atlantic states, which will result in slightly cooler temperatures
for the second half of the work week. Expect highs mainly in the
upper 80s to lower 90s, with overnight lows in the in the mid to
upper 60s. The next upper level trough is forecast to approach the
area next weekend, possibly bringing an increasing chance of showers
and thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 90 69 93 72 / 30 20 20 5
San Angelo 92 69 95 71 / 30 20 10 5
Junction 91 70 95 71 / 20 10 20 5
Brownwood 91 70 93 70 / 20 20 20 5
Sweetwater 89 69 91 71 / 30 20 10 5
Ozona 91 69 93 70 / 20 10 5 5
&&
.SJT Watches/Warnings/Advisories...
None.
&&
$$
07/99/07
Area Forecast Discussion...UPDATED
National Weather Service Tallahassee FL
1049 AM EDT SAT SEP 17 2016
.NEAR TERM [Through Today]...
The 8 am EDT regional surface analysis showed a ridge along the
Piedmont, and a weak trough (oriented north to south) centered
near Apalachicola. Vapor imagery and upper air data showed a weak
trough, an MCV from a large cluster of earlier thunderstorms,
centered along the LA coast. Higher heights were over east FL,
along with progressively drier air (from west to east). The RAP
analysis showed weak Q-G forcing over the western half of our
forecast area, and there were scattered light showers and isolated
thunderstorms, as well as abundant clouds in this region.
Our normally-reliable local CAM ensemble, as well as the NCAR CAM
ensemble, are drier than the rest of the NWP guidance, though
their PoP distribution matches the others. Why this is is unclear;
perhaps the cloud cover will mute the sea breeze forcing
somewhat? Nevertheless, this guidance has not initialized all that
well, and there is plenty of deep layer moisture to support
convection, though MLCAPE profiles are quite skinny (i.e. rather
low CAPE). Given these conflicting factors, we think it best to
just leave the previous forecasters` PoP/QPF forecasts alone,
sticking with high PoPs (50% or more) west of Tallahassee and
Albany. The only slight change we made was to nudge this
afternoon`s temperatures down a few degrees across much of the
region based on the extensive clouds.
&&
.PREV DISCUSSION [651 AM EDT]...
.SHORT TERM [Tonight Through Monday]...
Deep layer moisture will continue to increase through Sunday ahead
of a mid to upper level trough. The latest MOS PoP guidance
including MAV and local ensemble of CAMs are now in fairly good
agreement showing portions of our CWA with good to likely chance for
convection Sunday. Have increased PoPs mainly across our SE AL and
Florida zones but have undercut guidance for now. The trough is
forecast to sharpen as it passes over and just to our east Sunday
night through Monday. A much drier airmass will filter in from the
northwest in its wake. PoPs Monday will be tapered 20% north to
30-40% south. Max temps will be around 90 Sunday and the lower
90s Monday. Lows will be in the lower 70s.
.LONG TERM [Monday Night Through Saturday]...
As the upper trough slides off the eastern seaboard Monday night,
deep layer ridging builds in and quickly noses eastward to the
Mid-Atlantic states. The latest EURO has now come in line with
the GFS solution showing what will likely be the remnant of Julia
getting trapped under the ridge moving westward and inland across
SE GA/NE FL during the middle of next week. The moisture
associated with this feature would likely spread over our CWA
increasing or chances for convection. Still not sold on this
solution so PoPs will remain in the slight to chance range
(20-40%) through most of the period. Highs will be in the low to
mid 90s and lows in the low 70s to upper 60s.
.AVIATION [Through 12Z Sunday]...
MVFR ceilings are scattered about the region this morning.
Restrictions have only been included at ECP and DHN as they are
most likely to be impacted. VFR will prevail at all terminals
outside of showers and thunderstorms by mid-morning. Storms are
likely at ECP and DHN this afternoon.
.MARINE...
The pressure gradient will remain quite weak for the next several
days with light winds and low seas.
.FIRE WEATHER...
Hazardous fire weather conditions are not expected over the next
several days.
.HYDROLOGY...
The local rivers were below their "action" stages, and are expected
to remain so for the next several days.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 88 73 91 74 93 / 40 20 50 30 30
Panama City 84 76 86 76 88 / 60 20 40 40 30
Dothan 86 71 90 72 92 / 50 20 40 30 20
Albany 91 71 91 72 93 / 20 20 30 30 20
Valdosta 91 70 91 72 92 / 20 10 30 30 30
Cross City 89 72 89 73 90 / 30 20 50 30 40
Apalachicola 84 75 86 76 87 / 50 20 40 30 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Fournier
SHORT TERM...Barry
LONG TERM...Barry
AVIATION...Harrigan
MARINE...Barry
FIRE WEATHER...Harrigan
HYDROLOGY...Fournier
Area Forecast Discussion
National Weather Service Columbia SC
557 PM EDT SAT SEP 17 2016
.SYNOPSIS...
High pressure ridging into the forecast area from the north will
weaken ahead of an approaching cold front. The weak front will
move through the area Late Sunday night and Monday. Julia will
linger off the southeast coast but most of its associated moisture
will remain east of the forecast area through Monday.
&&
.NEAR TERM /THROUGH SUNDAY/...
Update: Mostly clear skies prevailed across The Midlands and CSRA
this evening. Expect stratus and fog to redevelop overnight with
deep low level moisture and light winds. No changes made to the
exsiting forecast.
Surface high pressure will continue to ridge into the Carolinas
and Georgia from the north with Julia meandering off the coast
today into tonight. A mid-level capping inversion will limit
convective development this afternoon. Scattered cumulus are
expected from daytime heating but are not likely to develop into
showers. The HRRR does show isolated showers moving inland from
the coast but dissipating before they reach the forecast area.
Tonight, upper level ridging over the southeastern states will
retreat to the southwest as a trough moves into the Mississippi
River Valley. Lows tonight will be in the upper 60s to lower 70s.
Models are suggesting deeper moisture and lighter low level winds.
It is likely that stratus and fog will develop again tonight
through late Sunday morning.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
The models show h5 troughing moving into the forecast area Sunday
and Sunday night with the trough over the region Monday. Difluent
h5 heights are depicted ahead of the trough Sunday and Sunday
night and a lead shortwave trough may move into the area Sunday.
The models are consistent with shallow moisture through early
Sunday. The shallow moisture and nocturnal cooling with light wind
should result in areas of fog during the early morning hours
Sunday. Moisture may become deep enough especially in the west
part for showers and thunderstorms Sunday afternoon. The NAM MOS
pops have trended upward and we have forecasted chance pops mainly
in the west part. There should be increased instability Sunday
night and Monday associated with the upper trough. However, low-
level convergence along the weak front should remain weak because
of the northwest flow on the backside of the offshore low. There
is high spread with the pop guidance. The GFS, NAM, ECMWF, and
EKD MOS have pops of 10 to 60 percent with the NAM highest. Kept
pops in the chance category because of the expected weak low-
level convergence. The NAM and GFS have surface-based LI values -4
to -8 with the GFS most unstable. Followed the guidance consensus
for the temperature forecast.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
There is low confidence during the medium-range period because of
model inconsistency. Previous runs of the GFS have displayed upper
ridging more dominate. The 12z run had an h5 cut-off low over the
area Tuesday through Friday with the upper feature beginning to
fill Friday. The latest run showed considerable wrap-around
moisture associated with low pressure near the coast with moisture
in an onshore flow continuing during much of the rest of the
period. The GFS MOS pops have increased to around 40 percent. The
GFS ensemble mean previously was 10 to 20 percent Tuesday and
Wednesday, and 20 to 30 percent during the rest of the period. The
GFS MOS high temperatures have also lowered. We have increased
pops and lower temperatures but not to quite the degree of the
latest guidance based on the inconsistency. Previous runs of the
ECMWF also indicated most of the moisture staying east and south
of the forecast area.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
No convection is expected to impact the terminals today. Models
have been consistent and are in good agreement indicating
restrictions late tonight and into Sunday morning. Deeper moisture
and lighter low level winds will support fog development and low
stratus. MVFR/IFR ceilings and visibilities likely after 08z
tonight. Higher confidence in LIFR early Sunday morning, included
in TAFS through mid Sunday morning.
EXTENDED AVIATION OUTLOOK...Early morning fog and stratus remain a
possibility through the period with a chance of mainly
afternoon/evening thunderstorms early next week.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
Area Forecast Discussion
National Weather Service Dodge City KS
342 PM CDT SAT SEP 17 2016
...Updated short term and long term discussion...
.SHORT TERM...(This evening through Sunday)
Issued at 335 PM CDT Sat Sep 17 2016
Shortwave trough was moving east southeast out of southern
Wyoming and northern Colorado this afternoon. Fairly cool mid
level temperatures around -15c associated with the wave is
helping destabilize the mid levels with clusters of strong to
severe thunderstorms breaking out over northeast and east central
Colorado. Farther southwest, convection was also breaking out over
the Raton Mesa. Instability axis has been situated over eastern
Colorado and south into far southwest Kansas and down through west
Texas. Better Bulk Shear values are also confined to the TX Panhandle
with marginal shear farther north. Best chance for severe should
be over the far southwest where parameters come together better.
A little more uncertainty as to how long convection over northeast Colorado
is sustained as it moves out into northwest and north central Kansas
this evening. Most model solutions have that convection dying out this
evening while the HRRR tends to sustain it all the way through central
Kansas. Storms could stay organized across southwest into south central
Kansas this evening and may need to increase pops across that area.
Things quiet down fairly quickly after midnight as the short wave trough
moves east out of the area.
Sunday will be mainly sunny as upper level ridging begins to build over
the central Plains. With increasing thickness values and weak low
level downslope, high temperatures should be a few degrees warmer
than today, around 85 to 90.
.LONG TERM...(Sunday night through Saturday)
Issued at 335 PM CDT Sat Sep 17 2016
Upper level ridging builds across the southern CONUS during the early
part of next week with the upper level westerly flow shunted
northward into the northern Plains and southern Canada. A shortwave
moving east along the US/Canadian border on Monday will push a
cold front south into the central Plains, possibly as far south as
I-70, on Monday afternoon. With a drier airmass in place by then,
the potential for storms looks minimal. Daytime high temperatures
should be up into the 90s during the first part of the week.
By mid week. the upper high gets suppressed a little farther south while
upper level southwesterly flow increases over the central Plains.
A shortwave lifts out over the central Plains on Wednesday. There
is some potential for perhaps some nocturnal storms across western
Kansas early Wednesday morning. This wave could push a boundary
into western Kansas during the day, providing focus for more
additional storm development. Temperatures should be cooling off
back into the 80s later in the week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1217 PM CDT Sat Sep 17 2016
Lingering scattered low clouds around Garden City should dissipate
rapidly at the beginning of the period. VFR conditions should prevail
through much of the period. Widely scattered to isolated thunderstorms
are expected to develop over eastern Colorado this afternoon and move
into western Kansas by late afternoon or early evening. Thinking that
the Garden City terminal will have the best chance for thunderstorm
impacts and have included a tempo group to reflect that this evening.
Less confident for thunderstorms around Dodge City and Hays but will
keep VCTS for a time at those locations this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 58 87 61 93 / 30 0 0 0
GCK 55 87 57 91 / 40 0 0 0
EHA 55 88 58 92 / 40 0 0 0
LBL 57 89 60 92 / 40 0 0 0
HYS 57 87 61 91 / 30 0 0 0
P28 60 86 66 93 / 30 10 0 0
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Gerard
LONG TERM...Gerard
AVIATION...Gerard
Area Forecast Discussion
National Weather Service Indianapolis IN
430 PM EDT SAT SEP 17 2016
.UPDATE...
The Aviation section has been updated below.
&&
.SYNOPSIS...
Issued at 147 PM EDT Sat Sep 17 2016
A cold front will sweep across central Indiana tonight and push
cooler and drier air into the state. Dry weather is expected in
the wake of the front for the second half of the weekend as High
pressure builds across the Ohio Valley.
The high will keep dry weather in place at least through Tuesday
and it slowly moves across Indiana to the Kentucky and Tennessee.
Another frontal system could bring more rain late in the week.
Tempertures will remain above average.
&&
.NEAR TERM /Tonight/...
Issued at 147 PM EDT Sat Sep 17 2016
Surface analysis early this afternoon shows a broad trough of low
pressure across Indiana. A cold front was found over NW
Illinois...and Central Wisconsin. Radar shows rain showers amid
the broad trough exiting central Indiana...although a few weak
showers were trying to develop within the troughy flow. a key
point can be seen within the water vapor imagery...were drying and
subsidence over Illinois was building east into Indiana...helping
to push a plume of moisture out of the state.
Main forecast challenge tonight will be ending precip chances and
dealing with temperatures.
This afternoon...the HRRR continues to suggest convective
development ahead of the cold front. It appears a bit over
aggressive. Still with forecast soundings showing reachable
convective temps...and isolated shra cannot be rules out. Thus
will keep some low chance pops in through 23z...as once heating is
lost precip threat will be over as subsidence will have pushed all
moisture well east of Indiana.
Forecast soundings and Time heights show excellent drying and
subsidence within the column through tonight as High pressure over
the plains builds eastward in the wake of the passing Cold front.
Time heights do show some lingering lower level moisture through
the night. Given the recent rains...light winds and limited
mixing...we will expect at least some patchy fog overnight as
models suggest dew point depressions of 1F or less. Given the weak
cold air advection...will trend lows at or slightly below mavmos.
&&
.SHORT TERM /Sunday through Tuesday/...
Issued at 147 PM EDT Sat Sep 17 2016
Main focus during this period will be temps. Aloft the models are
suggesting a broad trough passing across the state on Sunday.
however with high pressure in place at the surface...along with
dry continental flow...no rain will be expected wit this feature.
Forecast soundings remain dry as do the time height sections.
Convective temps in the mid and upper 70s should result in the
sct cu...but a mid level inversion should prevent any growth. Thus
will trend toward a partly cloudy sky and use a blend on HIghs.
Upper flow on Sunday night through tuesday suggests upper ridging
evolving to mainly a zonal flow by Tuesday. Forecast soundings
remain very dry as do the Time height sections. Meanwhile at the
surface...large and broad high pressure is expected to settle
across the Ohio valley. Furthermore...mid levels show good
subsidence through the period and strong high pressure building
through the Mississippi river valley. Thus will trend toward
partly cloudy days and mostly clear nights and a blend on temps.
&&
.LONG TERM /Tuesday night through Saturday/...
Issued at 232 PM EDT Sat Sep 17 2016
The long term will generally be controlled by a broad upper ridge
covering much of the central U.S. This will bring warmer than
normal temperatures and dry weather to the area. By the end of the
week a frontal system could approach, but the timing on this is
still very uncertain. Generally accepted the initialization of
slight chance pops coming in starting Friday night. Changes were
made to increase high temperatures from the initialization under
the upper ridging and southwesterly component flow from Thursday
on.
&&
.AVIATION /Discussion for 17/21z TAFs/...
Issued at 430 PM EDT Sat Sep 17 2016
Removed VCSH mention and raised conditions to VFR at IND per obs.
Previous discussion follows.
Issued at 108 PM EDT Sat Sep 17 2016
Off and on MVFR ceilings possible over the next few hours. A few
showers will still be around but for the most part sites should be
dry and will leave out any mention beyond vicinity. Then overnight
expect some fog to develop, especially in areas that saw the most
rainfall this morning. Will go with the lowest conditions at KBMG
with 1/2sm, 1sm at KIND and KHUF and stick with MVFR at KLAF.
Winds through the rest of the day should be 3-8 kts out of
220-270, with light and variable winds overnight.
&&
.IND Watches/Warnings/Advisories...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...CP
AVIATION...CP/NIELD
Area Forecast Discussion
National Weather Service Morristown TN
251 PM EDT SAT SEP 17 2016
.SHORT TERM (This Afternoon through Sunday)...
Another hot and dry day across the area with a cold front located
back to the west near the Mississippi River. Current water vapor
imagery and RAP upper air analysis indicates an upper level trough
moving into the Great Lakes region. Radar and satellite imagery
shows an area of showers/storms across Kentucky stretching southward
into North Alabama. Expect this line of shower/storms will weaken as
they continue to move to the northeast. Surface dewpoints across the
region are in the upper 50s to low 60s with PW values in the 1.3-1.6
inch range with the higher values across the Plateau. As for the
remainder of the afternoon, expect the best chance for showers/storms
will be across the Plateau where the best moisture values are. The
850 mb jet will increase slightly late tonight into tomorrow
morning and expect coverage will begin to increase during this
timeframe. Low level cloud cover and continued southerly flow will
keep temperatures up tonight into the mid 60s to low 70s.
Widespread cloud cover and precipitation is expected tomorrow ahead
of the advancing cold front. The widespread cloud cover should keep
high temperatures in the upper 70s to low 80s and reduced highs from
the previous forecast by about 5 degrees or so. PW values will
increase into the 1.7-2.0 inch range during the day tomorrow. These
values are well into the 99th percentile for mid-September.
Therefore, this will be the best chance for rain throughout the next
7 days. As for rainfall amounts, it looks as though 0.50-0.75 inches
with some locations possibly up to an inch. This should help briefly
with the ongoing drought conditions.
.LONG TERM (Sunday Night through Saturday)...
Front will finally push through the rest of the area Monday evening
and shower/thunderstorm chances will quickly diminish behind the
front from west to east. Not only do the rain chances go away
quickly, but the cooler temperatures will also quickly go away as
well. We will likely see temps climb back towards 90 degrees in many
locations by the middle of the week. Some of the models want to
generate light QPF at various times during the week with some
moisture in the area... But have gone ahead and left mention out of
the forecast for now since models have continued to over forecast
rainfall chances throughout this summer. Next best rain chances will
likely hold off until another frontal boundary moves towards the
area next weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 71 85 69 89 / 50 60 30 10
Knoxville McGhee Tyson Airport, TN 70 82 66 85 / 50 60 30 10
Oak Ridge, TN 69 82 67 86 / 60 70 30 10
Tri Cities Airport, TN 65 79 63 83 / 20 60 40 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&
$$
MA/ABM
Area Forecast Discussion
National Weather Service Paducah KY
241 PM CDT SAT SEP 17 2016
.SHORT TERM...(Tonight through Monday night)
Issued at 241 PM CDT Sat Sep 17 2016
Radar pretty quiet. Only spotty light rain/showers since mid
morning. Little activity currently. Will maintain a very low
chance PoP into the early evening over the east 2/3 of the area.
RAP shows limited elevated instability, thus will keep slight
chance TSRA. But overall, not much expected.
Next system will be a s/wv moving from the central Plains to the
TN Valley Sunday/Sunday evening. Most of the moisture stays to our
south, so dry forecast for now. Dry weather will continue Sunday
night through Monday night as well. In the wake of the s/wv, weak
high pressure will be in control.
Temps will be a blend a MOS blend. We will monitor the fog potential
overnight. It is in the forecast. Lows should cross over most areas.
Could be low clouds as well.
.LONG TERM...(Tuesday through Saturday)
Issued at 241 PM CDT Sat Sep 17 2016
Upper level ridge is in place from Wednesday into Friday. On Friday
heights fall slightly on all models as upper level low forms over
the northern Rockies. By 18z Saturday, the upper level low moves
into the northern plains with the GFS having a more negative tilt
than other models and ensembles and thus much faster with the cold
front.
More interesting to us is the moisture pattern forecast. Moisture
off the southeast coast early Tuesday is forecast to move under the
ridge toward the west and northwest. Although models vary on the
details including timing, it looks like the best chance for
precipitation will be on Saturday.
With the ridge over the area, expect temperatures to be well above
normal at least until Friday. Normal highs are in the lower 80s,
expect to see upper 80s to lower 90s during that time.
&&
.AVIATION...
Issued at 1204 PM CDT Sat Sep 17 2016
Widespread cloud cover over the region this afternoon, though
coverage decreases heading NW toward east central MO into west IL.
Will maintain low VFR to MVFR cigs. Radar also detects spotty
light showers / light rain, and will include in all but the KCGI
TAF based on trends. Will scatter out clouds tonight. However from
06z on, there could be some fog to deal with, with near calm
winds. Will indicate MVFR vsbys for now. Lower clouds cannot be
ruled out either. Taking a minimal mention approach for now so
later shifts can adjust accordingly.
&&
.PAH Watches/Warnings/Advisories...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
350 PM EDT SAT SEP 17 2016
.SYNOPSIS...
19Z water vapor and H4 RAP analysis shows broad mid/upper level
ridging over the Florida peninsula and eastern gulf this
afternoon. The main northern stream flow is well removed to our
north and northwest...and this is where it will stay through the
remainder of the weekend. The pattern overhead is fairly
seasonable for mid- september and will yield a fairly seasonable
forecast into the early portion of the the week. 12Z KTBW RAOB
sampled a pretty moist column between the surface and 400mb...with
lapse rates averaging near moist adiabatic...and a well above
average PW value around 2.25". The depth of moisture will once
again not hinder the development of convective cells across much
of the region...however...the poor lapse rates through a deep
layer of the trop will limit the strength of the convective
updrafts and potential for any abnormally strong thunderstorms.
At the surface...the Florida peninsula resides within a weak
pressure gradient between high pressure ridging down from the
southeastern states into the eastern Gulf of Mexico...and what is
left of tropical depression Julia still spinning off the
GA/Carolina coasts. Overall the pattern favors a light east/NE
wind flow across our area...however...the weak gradient and strong
diurnal heating will force a well-defined sea-breeze and turn
winds onshore near the coast for the majority of the
afternoon/early evening.
24-48 hours ago...the guidance was showing a decent swath of drier
mid-level air arriving over the Nature coast by this afternoon as
it pivoted down around the Julia circulation. If now appears as
though the driest of this air will be staying just to our north
and northeast...and the negative impacts on convection will not
be realized to the degree thought earlier.
Generally speaking...now that the sea-breezes have becomes fully
developed...and we are at peak heating...a scattering of storms
will continue to pop into the early evening...with storms tending
to come together along the I-75 corridor for the early evening.
This is a scenario shown by the HRRR for several runs now. Based
on the KTBW RAOB...winds are still light in the mid- levels...but
at least today there is a more defined direction...blowing
northeast to southwest. Would expect this motion toward the FL
west coast to be the majority storm movement once storms become
mature and are tall enough to feel this flow aloft.
&&
.SHORT TERM (Tonight through Sunday)...
Not a whole lot of change in the synoptic pattern as we head
through the overnight and into Sunday compared to what is
described above in the synopsis. Storms are likely to line up near
the I-75 corridor during the evening as both coast breezes
collide. These storms will then fade by 02-03Z and give way to a
mostly dry overnight period with slowly clearing skies (at least
initially). The light north to northeast flow advertised by the
guidance with abundant low level moisture and weak ridging aloft
is a favorable setup for some lower stratus development in the
pre-dawn hours across NE Florida that will then slowly expand
south and west toward the I-4 corridor. We saw a bit of this
stratus this past morning...and expect it once again. Latest SREF
ensembles are also showing elevated probabilities of lower cigs by
dawn. This stratus does not really impact the public forecast as
it burns off quickly once the sun rises...but can be quite
influential in early morning aviation operations.
Similar to today...A dry morning and early afternoon will give way
to a building cumulus field and eventually a scattering of showers
and storms for the later afternoon and early evening hours. Still
waiting for all the 12Z guidance to arrive...but planning on rain
chances Sunday afternoon in the 30-40% range for most
locations...with perhaps slightly higher numbers down toward
Charlotte, Highlands, and Lee counties. High temperatures across
the region on Sunday will top out in the upper 80s to around 90.
&&
.MID/LONG TERM...
Weak low-level flow to start the week will gradually transition as
surface and mid level high pressure looks to become re-established
across the region, bringing sustained east to northeast flow into
next weekend. There will be subtle changes from day-to-day in
regards to atmospheric moisture content but nevertheless PoPs will
be in the 40-60% range through the forecast period.
As the calendar turns to fall on Thursday, those hoping for some
"fall-like" weather can keep dreaming or look much further north as
it will continue to feel like summer across the area. Temperatures
near 90 each and everyday will continue with dewpoints in the low to
mid 70s keeping heat indices near 100.
&&
.AVIATION...
VFR for all terminals into the evening hours...other than the
potential for a brief thunderstorm. Any restrictions associated
with storms will be brief...with storms fading away within a
couple hours of sunset this evening. Similar to this
morning...areas of lower stratus are likely to migrate south and
west into the I-4 corridor around dawn...and possible down as far
as KPGD. Will continue to monitor guidance trends and hint at some
lower clouds with afternoon TAF package between 09Z- 13Z Sunday.
&&
.MARINE...
A quiet and seasonable weather pattern across the eastern Gulf of
Mexico through the early portion of next week...as weak high
pressure remains in control. Light easterly winds overnight and
during the morning hours will give way to developing onshore flow
near the coast each afternoon. Isolated to scattered storms can
also be expected in the vicinity of the coast late each afternoon
and early evening.
&&
.FIRE WEATHER...
No significant fire weather concerns are anticipated through the
early portion of the week. Generally light flow will remain in
place across the Florida peninsula...with abundant low level
moisture to keep relative humidity values above critical levels.
We are likely to see a daily scattering of afternoon storms...with
temperatures and rain potential near normal for this time of year.
Fog Potential...Some patchy fog is likely late tonight...especially
from I-4 northward across the Nature coast...however...No
significant areas of widespread or dense fog are anticipated.
&&
.Preliminary Point Temps/PoPs...
TPA 76 89 77 88 / 20 30 20 50
FMY 76 89 76 89 / 20 40 20 60
GIF 75 90 75 89 / 20 40 20 60
SRQ 77 87 76 87 / 20 30 20 50
BKV 74 90 73 89 / 30 40 20 50
SPG 77 89 78 88 / 20 30 20 40
&&
.TBW Watches/Warnings/Advisories...
FL...None.
Gulf waters...None.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...Mroczka
MID TERM/LONG TERM/DECISION SUPPORT...McKaughan
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
604 PM CDT SAT SEP 17 2016
.SHORT TERM...(This evening through Sunday)
Issued at 251 PM CDT Sat Sep 17 2016
After a round of morning fog, skies have become mostly sunny
across the area with highs reaching into the low 80s for most
locations. Convection has formed across the high plains of
Colorado and far western Kansas, and is slowly making its way
eastward. Upper wave associated with this development extends from
South Dakota into south central Colorado. Showers have bubbled up
over north central Kansas but have dissipated as they move east.
For tonight, will need to watch high plains convection, at this
time only have some slight chances for thunder mainly south and
west of Concordia. HRRR has been bullish at bringing convection to
just west of Manhattan, but most remaining guidance keeps CAP in
place and with not enough energy to develop elevated convection,
dissipates the northern storms and focuses more on the convection
rolling out of southern Colorado through the panhandles and
through northern Oklahoma. Overnight lows fall into the 50s. On
Sunday, not expecting a repeat of the fog given increasing
southerly winds through the period, with high temperatures a few
degrees warmer today in the middle 80s.
.LONG TERM...(Sunday night through Saturday)
Issued at 251 PM CDT Sat Sep 17 2016
No major changes or highlights to the previous forecast. Models are
in smilier agreement with the main jet stream carrying embedded
upper waves across the far northern CONUS while an upper ridge
dominates the southern plains and a cut off low rotates off the CA
coast. Unlike consensus guidance, the GFS consistently develops a
weak vort max from southern OK through the Great Lakes region Sunday
night. Forcing is weak and available moisture is non existent on
forecast soundings so I continued with a dry forecast. The heat is
expected to return Monday with the upper ridge expanding northward.
Southerly flow persists at 10 to 15 mph towards the sfc Monday and
Tuesday afternoons. A weak cold front is progged to pass through the
area dry Monday evening while weak winds veer back around to the
south Tuesday afternoon. The lack of cool air behind the boundary
and some compressional warming in the vicinity has raised guidance
values to the lower 90s for highs both afternoons.
Beginning Wednesday evening, sfc troughing over the western high
plains is anticipated ahead of a strong upper low building over the
northwest CONUS. Lead upper trough shifts over the central plains
Wednesday evening, introducing slight chances for thunderstorms. As
the above mentioned upper low approaches the region, occasional
storm chances continue before a strong cold front sweeps through the
area Friday evening. Throughout the week, highs in the middle 80s
and overnight lows in the upper 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 601 PM CDT Sat Sep 17 2016
VFR conditions are expected throughout the period. Fog is possible
near dawn tomorrow morning. However, current thinking is cloud
cover associated with the thunderstorms across western Kansas
shall move over the terminals overnight and hinder fog
development. Southerly winds will increase after 15Z to near 10
knots.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Prieto
AVIATION...Baerg