Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/30/16
Area Forecast Discussion
National Weather Service Binghamton NY
1036 PM EDT Thu Sep 29 2016
.SYNOPSIS...
Unsettled and occasionally wet weather will continue through the
weekend as a large and slow moving storm system impacts the
region. Drier conditions are expected early next week as that
system weakens.
&&
.NEAR TERM /THROUGH FRIDAY/...
1030 PM Update...
New area of rain over Eastern PA and NYC area finaly making more
progress into our area. The latest HRRR while slightly fast and
too far north, is handling this area of precipitation the best.
Much like last night however I had to tighten our gradient with
rain approaching so slowly. The 1036 MB high over eastern Quebec
is allowing enough ridging and drier air at low levels to really
impede the northward progression of the rain, much like it has
most of the past 24 hours. Slowly this shield of rain will move
northwest across our CWA but may not reach Binghamton area until
just after midnight. Rainfall amounts are fairly light, or just a
few tenths of an inch. The previous AFD is below.
130 pm update...
Two main weather players will remain dominant this period; the
large cutoff low in the Ohio Valley and the expansive surface high
over southeastern Canada. An east-southeast flow will continue
across central NY/northeastern PA around these features.
Showers are temporarily rotating northwestward and out of the
forecast area this afternoon. As somewhat drier air pushes in from
New England, we will be generally rain-free from late this
afternoon through a good portion of tonight.
Later tonight and Friday, another area of moisture and lift will
move in from the southeast (seen on radar imagery as an area of
steadier rain at this time over southern NJ and along the Delmarva
coast). This will lead to a lowering of clouds and increasing
coverage of light rain. Thus, shower probabilities will increase
into the likely range again for at least northeastern PA and NY`s
southern tier.
Highs Friday (similar to today), should range from the upper 50s-
mid 60s.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
415 PM Update...
Cutoff low will remain almost stuck in position through the
weekend. It will be initially parked over the Lower Ohio Valley to
Western Great Lakes, with shortwaves ahead around it from south to
north through our region. Showers will be possible at just about
anytime depending on timing of the individual waves, though with
enhancements during the daytimes due to the energy injected via
diurnal heating.
With the good deal of cloud cover through the weekend, the
temperature range will be fairly narrow. Highs will trend from
mainly lower-mid 60s Saturday, to mid 60s-near 70 Sunday. A few
spots in the northeastern zones could manage upper 40s for lows
Friday night, otherwise lows over the weekend will generally be
lower to mid 50s.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
415 PM Update...
Upper low will be filling in and weakening early next week. It
will try to progress through the area but there is uncertainty on
how long that will take. Temperatures will change little, and
there will still be a fair amount of clouds around. However, with
the upper low weakening, shower chances appear slight at best
early next week.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
VFR conditions across the board this evening will deteriorate
through the overnight hours, as another area of lower stratus
clouds and light rain moves in. MVFR clouds will spread northward
tonight and begin to impact KAVP around 08-10z. The low clouds
will slowly push north and impact KBGM, KELM and KITH through the
rest of the morning and into the early afternoon...with periods of
IFR possible. Areas to the north...KSYR and KRME will likely see VFR
conditions through the period...but a brief rain shower and
temporary MVFR cigs cannot be ruled out. Conditions should start
to improve around or just after 00Z Saturday.
Easterly surface winds 5-10 kt will persist with a few gusts to 15
kt in the morning.
OUTLOOK...
Saturday night-Sunday...Occasional restrictions possible from
lower ceilings and showers.
Monday-Tuesday...Mostly VFR. Early morning fog possible at KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MDP
NEAR TERM...Heden/MLJ
SHORT TERM...MDP
LONG TERM...MDP
AVIATION...BJT/MLJ
Area Forecast Discussion
National Weather Service Bismarck ND
933 PM CDT Thu Sep 29 2016
.UPDATE...
Issued at 930 PM CDT Thu Sep 29 2016
At 930 PM CDT Bowman radar indicated a few showers just southwest
of the state. The forecast is trending ok starting a slight chance
of showers just before midnight southwest. Temperatures and winds
look good. Current forecast trending ok.
UPDATE Issued at 633 PM CDT Thu Sep 29 2016
Surface low pressure across eastern Montana will be the focus for
scattered showers tonight west. Latest HRRR model continues to
show scattered showers southwest after 10 PM CDT. Currently skies
are clear but clouds will soon arrive from WY/MT. So far forecast
is trending well. Will only need to update current conditions.
&&
.SHORT TERM...(This evening through Friday)
Issued at 225 PM CDT Thu Sep 29 2016
Isolated to scattered showers tonight into Friday morning west
into the north central highlights the short term forecast.
The 12 UTC global and the high resolution rapidly updating suites
through 17 UTC are in agreement on a shortwave across Wyoming
this afternoon propagating northeast tonight into western North
Dakota. Isolated to scattered showers are forecast with this wave
across the west and north central tonight into Friday morning.
There is a small chance of a thunderstorm with steep mid level
lapse rates, however, not much lightning has been observed with
this wave thus far across Wyoming this afternoon.
.LONG TERM...(Friday night through Thursday)
Issued at 225 PM CDT Thu Sep 29 2016
Increasing precipitation potential early to mid next week
highlights the extended forecast.
The 12 UTC global suites are in general agreement on an upper
level low coming onshore to northern California or Oregon Sunday
potentially propagating into the Central or Northern Plains
Tuesday into Thursday. While there is a spread amongst the
guidance suite in the track of the low, the feature itself is
favored. This system will have to be monitored for potential
widespread precipitation including the slight chance for a few
snowflakes mixing in on the back side of the low Wednesday night
into Thursday morning. Prior to the arrival of the low Sunday
into Monday, there is a chance of showers and thunderstorms with
impulses embedded in southwest flow aloft.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 633 PM CDT Thu Sep 29 2016
Hazards to aviation include low level wind shear. Surface low
pressure across eastern Montana will move very slowly east tonight
and Friday. The low will be the focus for scattered showers over
western North Dakota tonight. Included wind shear for KISN-KMOT-
KBIS for increasing low level winds to 35kts at 2 thousand agl.
Otherwise VFR at all TAF sites.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
AVIATION...WAA
Area Forecast Discussion
National Weather Service State College PA
1127 PM EDT Thu Sep 29 2016
.SYNOPSIS...
Showery conditions will prevail overnight. Any flooding would be
localized and minor with little in the way of impacts. Unsettled
weather with occasional lighter rain showers will persist into the
weekend with a gradual drying trend by early next week.
&&
.NEAR TERM /UNTIL 8 AM FRIDAY MORNING/...
Still a neat little box around 95 pct of central PA where no
radar echoes exist. It is drizzly at may locations, but that stuff
is too low (and the droplets too tiny for most 10cm radars) to
pick up. A slight increase in radar echoes is starting to move in
from the south and precip in DE also sliding just a little to the
west of north. HRRR and RAP doing well with the first couple of
hours in the past few runs, so higher than normal confidence
exists that they will do well with the rest of the night. 00Z NAM
arriving and continues to make heavier rain than other mdls. The
placement of the heavier rain is mainly to the east of the Susq
and is an area where generally less rainfall occurred. That area
has also had a decent break of time since any real rain has
occurred. Grid work with this update was mainly to dip the POPs to
=<20pct in the north for the next few hrs. However, the guidance
is big on developing the precip associated with a wave moving up
the MidAtlantic coast. This area would then blossom as it enters
eastern PA and make the heaviest rain in the east for a few hours
either side of sunrise while lifting north. The northern mtns
should then have their best shot at some rain during the daytime
on Fri.
Prev...
Rainfall down to nil at the moment with central PA in the dry slot
between a higher plume of moisture to the east and another to the
west. Newest progs yield only light to what might be considered
modest amounts of rainfall through sunrise. 18Z NAM seems like a
high-end outlier on QPF amount - and only for a small area. Stream
response has been very little if anything on the medium to larger
streams. Even NAM amounts and placement will not cause widespread
flooding problems. The ground and still-growing vegetation are
gladly soaking it up. Have decided to chop the rest of the Flood
Watch off. Have adjusted POPs in the very near term to account for
the dry slot and GFS/HRRR/RAP evolution of the rain for the rest
of the night.
Prev...
2.5 to 3.5 inch amounts feel across southern tier overnight
through midday...with higher amounts likely on the east facing
slopes occurred across the southern tier. Flooding threat
remains...albeit low...with upslope areas susceptible to any
persistent upslope or training convective showers over the next
18 hours which could add another 1 to as much as 2 inches in some
spots.
Dry slot over western PA with high cloud covering eastern brought
transition to low topped open cellular activity propagating from
southeast to northwest today. Thus a more showery regime took over
with times of little or no rainfall and other times with brief
moderate to heavy rates accumulating a few tenths of an inch at
time.
Moderate PW transport along with some elevated instability will
maintain a favorable environment for mdt-heavy rain/efficient
rainfall processes through this evening, while increasingly
diffluent flow aloft supports some training bands in addition to
the trend to low topped open cellular character. In
fact...training bands have organized over nrn VA/MD at mid
afternoon and are moving into the Laurels and South Central
Mountains...as anticipated earlier.
Still expecting storm totals of 2-4" over the remaining flood
watch area with locally 5"+ possible along the east-facing slopes
and highest terrain. Very dry antecedent conditions resulting in
3-6hr FFG values of 4+ inches along with below normal stream flows
should help to mitigate flooding to some extent, however if the
higher end amounts are realized flooding impacts/runoff issues
could become more serious.
&&
.SHORT TERM /8 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
The Large low will be quasi stationary and will continue to stream
moisture into Southwestern PA through tomorrow. Strong E-SE LLJ
and above normal PW along with associated forcing on
east/southeast side of upper low favors scattered to numerous
lighter rain showers through the period. The mid range models are
keying in on a mid level short wave trough that forms to the east
of the low and should increase rainfall rates and amounts through
Central PA as it is coupled with the LLJ and the PWATS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
The upper level low will continue to spin slowly northward into MI
and continue on into Southern Canada. The low will slowly be
pulled into the upper level flow and cold air advection will
filter into the region early into next week. The final vestiges
of the low that has dominated our weather pattern this week will
finally lift and move off coast by mid next week by the upstream
amplifying trough over the central CONUS. High pressure should
regain control of the large scale pattern. The 12Z GFS comes more
into alignment with the EC however the EC continues the path of
the TC Matthew much slower and keeps it off the coast of Florida,
where the GFS brings the projected path up the Atlantic coast and
has the system nearing the NC coast by Thursday morning.
Temperatures will be slightly below normal through the weekend,
before shifting to slightly above normal by the middle of next
week.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
Minor changes made to 03Z TAFS.
Low clouds and areas of light rain, drizzle, and fog will
linger across the area, given strong easterly flow of moisture
off the ocean. MVFR to LIFR conditions will prevail into at
least Friday.
Again, not much change expected overnight or on Friday.
Outlook...
Sat...Low cigs/showers likely, mainly w mtns.
Sun...AM low cigs possible.
Mon...Showers/cig reductions possible at KBFD.
Tue...Fair.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...DeVoir/Steinbugl
NEAR TERM...Dangelo/DeVoir/Steinbugl
SHORT TERM...DeVoir/Ceru/Steinbugl
LONG TERM...Ceru/Steinbugl
AVIATION...Martin
Area Forecast Discussion
National Weather Service Duluth MN
645 PM CDT THU SEP 29 2016
.SHORT TERM...(This evening through Friday)
Issued at 340 PM CDT Thu Sep 29 2016
Despite a broad area of high pressure across the Upper Midwest, much
of northern Minnesota and parts of northwest Wisconsin are under a
stubborn cloud deck trapped within an inversion. Still, it looks
like late today this inversion should somewhat mix out resulting in
clearing across parts of the region, though by that point the high
pressure will departing to the north. Tonight clouds return as the
abundant boundary layer moisture condenses, resulting in a stratus
deck. While this still looks to be the coolest night of the week,
the cloud cover will limit lows to the mid 40s, though some spots
across the MN Arrowhead could fall to the low 40s if skies are not
as cloudy as currently anticipated. MOS guidance has been
consistently cooler with lows close to freezing in some runs, but
looking at the actual text bulletin, it appears MOS might not be
taking into account the stratus we expect to develop.
The upper level low responsible for all this low level moisture -
currently over the Tennessee Valley - decides to take a visit back to
the Great Lakes this weekend, and as it approaches from the
southeast, low level winds will be out of the east tonight into
Friday. This will result in the dry slot evident on water vapor and
visible satellite imagery to build into the Northland, finally
resulting in what should be a mostly sunny afternoon across the
Northland. Temperatures will be warmer with highs in the mid to
upper 60s, except near Lake Superior and especially in the Twin
Ports and along the south shore where winds off the lake will limit
highs to the upper 50s to near 60.
.LONG TERM...(Friday night through Thursday)
Issued at 340 PM CDT Thu Sep 29 2016
The forecast area will remain positioned between low pressure
rotating to our south near Chicago, and high pressure anchored to
the north over Ontario. This will keep majority of the Northland dry
through the weekend. The exception will be a chance for light rain
possibly pushing as far north as the Park Falls area in northern
Wisconsin Saturday.
The resulting pressure gradient will allow for east winds to prevail
across the Northland through the weekend. The flow will turn
southerly and strengthen through the beginning of next week as the
next low pressure system advances into the Dakotas.
Latest runs of the GFS/ECM are in surprisingly good agreement with
the low that will impact the region next week considering its out on
day 5 and beyond. The long wave trough, with closed 500hPa low, is
projected make landfall on the western coast Sunday, then migrate
east across the central US and into the Northern Plains by
Wednesday. This track will allow for a warm front to lift over the
region early in the week, bringing a surge of warm gulf air along
with a chance for showers and thunderstorms with it. Once the low
passes over the western Lake Superior region and cold air advection
makes a return for the upcoming weekend, a much cooler airmass with
850hPa temps well below zero will dive into the Northland. This may
be our first shot at light snow accumulations along the borderland.
However, suspect overall timing of the long wave trough and
associated stacked low/precipitation chances will be slower than
currently in forecast. This is due to model bias of typically
progressing closed systems too fast, as well as the impact of the
tropical storm approaching the east coast during this time; which
the GFS and ECM are showing large differences with.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 645 PM CDT Thu Sep 29 2016
High pressure centered just north of Lake Superior with a ridge
extending southwest through Minnesota will only move slightly
north through the period. VFR ceilings over northeast Minnesota
are expected to continue to slowly diminish per the latest RAP and
satellite supports a slow clearing trend. However, MVFR and IFR
ceilings are expected to expand in a persistent easterly flow. Fog
will also be possible tonight and we have a mention in the TAFs
later tonight into Friday morning. The lower ceilings and fog are
expected to lift Friday morning leading to VFR conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 43 60 49 62 / 0 0 0 0
INL 43 65 45 66 / 10 0 0 0
BRD 46 68 47 66 / 0 0 0 0
HYR 44 65 47 63 / 0 10 10 10
ASX 47 57 50 61 / 10 10 10 10
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...JJM
LONG TERM...Graning
AVIATION...Melde
AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
650 PM CDT Thu Sep 29 2016
...Updated Aviation Discussion...
.SHORT TERM.../This evening through Friday/
Issued at 334 PM CDT Thu Sep 29 2016
Little of concern tonight outside of possible fog redevelopment. The
Ohio Valley upper low should remain nearly stationary with clear
skies across Iowa. The broad low level cyclonic flow continues to
drawn in some lower humidities, especially east, however the latest
RAP shows somewhat higher 0-500m RH north and west. This is also
where early morning stratus and fog lingered so have introduced some
patchy fog wording there early in the morning with clear skies and
light wind.
.LONG TERM.../Friday night through Thursday/
Issued at 334 PM CDT Thu Sep 29 2016
The more likely window for sensible weather through this period will
be toward the middle of next week, although the current Ohio Valley
upper low may just brush Iowa with light precip over the weekend.
The models are in good agreement drifting the system back to
southern Lake Michigan by late Saturday. The forcing will be neutral
or subsident but increasing moisture 3km and below may be sufficient
to squeeze out some light showers east. The system should finally
depart to end the weekend as the western CONUS trough advances.
This will increase temps and moisture somewhat as return flow
begins and ridging enters Iowa. The GFS and ECMWF are now fairly
consistent and suggest deep forcing increasing west to east
Tuesday Night into Wednesday. Timing is still somewhat suspect
however with the ECMWF frontal passage much faster, so while the
best window appears to be around Wednesday have lingered some low
PoPs east into Thursday. Instability looks weak regardless of the
solution, but both deep and shallow shear are quite high. This
suggests somewhat of a weak, subtle fall QLCS tornado threat if
diurnal timing is favorable due to the high shear values 3km and
below.
&&
.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 650 PM CDT Thu Sep 29 2016
VFR conditions will prevail through the entire forecast period.
Fog is possible by Friday morning and may impact FOD and MCW, but
low confidence in mentioning attm.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Small
LONG TERM...Small
AVIATION...Podrazik
Area Forecast Discussion
National Weather Service Quad Cities IA IL
650 PM CDT THU SEP 29 2016
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 300 PM CDT Thu Sep 29 2016
18Z surface analysis has high pressure from the upper Great Lakes
into the southern Plains while a cut off upper low was over the
lower Ohio Valley. Dew points were in the 40s and 50s from the
Plains into the Ohio Valley.
&&
.SHORT TERM...(This Evening through Friday)
ISSUED AT 300 PM CDT Thu Sep 29 2016
Through sunset, mainly clear skies will be seen across much of the
area with clouds and isolated showers/sprinkles across the far
eastern parts of the area. After sunset and through much of the
evening, isolated sprinkles/showers will gradually decay across the
far east.
The upper low over Kentucky will remain there through Friday. Trends
with the RAP and other models indicate another surge of low clouds
will spread west again after midnight with widespread cloud cover
over the eastern two thirds of the area around sunrise Friday.
On Friday, several additional upper level disturbances will rotate
through the area. These disturbances will slowly spread isolated to
scattered rain showers west across the area during the day.
The initial dryness of the air indicates some chilly temperatures
are possible tonight, especially those areas that remain clear.
On Friday, cloud cover/precipitation will make temperatures very
interesting. High temperatures should eventually get into the 60s at
some point during the afternoon.
.LONG TERM...(Friday Night through Thursday)
ISSUED AT 300 PM CDT Thu Sep 29 2016
Forecast focus on chance of showers early in the extended then
chance of thunderstorms about the middle of next week.
Friday night through Saturday: Vertically stacked upper low in KY
will track slowly northward into northern Indiana. The cyclonic
flow/cold pocket around the low will bring a mostly cloudy sky to
the dvn cwa, along with scattered showers. The higher pops (40-50
pct) will be kept roughly along and east of the MS River, closer to
the low. In our far western counties pops will be in the 20-30 pct
range. Highs on Saturday should range from 65 to 70 due to the
extensive thick cloud cover.
Saturday night through Tuesday night: A pleasant stretch of weather
expected, dry with a warming trend. The upper low will be shifting
into the eastern Great Lakes during the weekend, while ridging aloft
builds into the cwa. Highs will be in the upper 60s to lower 70s on
Sunday, warming well into the 70s by Tuesday. Lows will be mainly in
the 50s.
Wednesday through Thursday: Low confidence due to potential Tropical
Storm or Hurricane Matthew moving up the East Coast (GFS) vs the
system still near the Bahamas (ECMWF). Both models sweep a negative-
tilt trough/strong cold front into the Midwest, accompanied by
showers and thunderstorms. So, there are two scenarios 1) the
tropical system slows the approaching trough or 2) the trough sweeps
to the east and merges with the tropical system. As of now, the ECM
with the slower movement to "Matthew" sweeps the cold front across
the cwa on Wednesday. On the other hand, with the tropical system
moving up the East Coast the GFS is about 24 hours later with the
arrival of the front. The consensus model has chance pops to cover
the two scenarios described above.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 644 PM CDT Thu Sep 29 2016
Wrap around clouds from a stalled upper low pressure system on the Ohio
valley will bring mostly bkn-ovc cigs with VFR conditions initially
dropping to 1-3K AGL or MVFR conditions toward morning into the late
morning hours before rising above 3k AGL. Winds will be north to northeast
at generally 10 to 15 MPH.
&&
.HYDROLOGY...
Issued at 1224 PM CDT Thu Sep 29 2016
Mississippi River:
Latest adjustments that were made was to slightly lower crest
forecasts at most points but minor to major flooding continues to be
on track. Forecast point DLDI4 Dubuque is expected to crest right at
flood stage with major flooding still expected at New Boston, Keithsburg,
Gladstone and Burlington. Majority of the crests are projected to
occur during the Saturday through Monday time frame. No significant
rain is expected through the middle of next week.
Cedar River...
Vinton: Forecast to fall below flood stage by Friday morning.
Cedar Rapids: Forecast to fall below major flood stage by late
tonight.
Conesville: Cresting near 18.1 feet through this evening
before beginning to slowly fall.
Wapsipinicon River...
Anamosa Shaw Rd: Forecast to fall below moderate flood stage by
the late evening.
De Witt 4S: Now into major flood stage. Thinking current crest
forecast at 13.4 feet is on the upper end of possible outcomes.
Reasonably high probability the final crest is a bit lower.
Iowa River...
Marengo: Moderate flood stage is forecast by Friday afternoon or
evening.
Columbus Junction: Major flooding is occurring. Rate of rise has
slowed but is forecast to increase tonight.
Oakville and Wapello: Moderate confidence is associated with the
crest forecasts. Current thinking is crest forecasts are toward the
upper range of what is possible; observed crests may come in lower.
Please follow forecast information closely throughout this event.
&&
.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...Haase
AVIATION...Nichols
HYDROLOGY...Haase/Uttech
Area Forecast Discussion
National Weather Service Northern Indiana
812 PM EDT Thu Sep 29 2016
.SYNOPSIS...
Issued at 805 PM EDT Thu Sep 29 2016
Low pressure will slowly drift back north into Michigan and
eventually Ontario over the next couple of days. Occasional showers
will occur overnight into Friday and then chances diminish
gradually through the weekend. then starting this evening and
persisting into Saturday. Highs will remain near to slightly
above normal in the middle 60s to lower 70s with lows in the 50s
for the next several days.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 237 PM EDT Thu Sep 29 2016
Thus far this afternoon convection has been to the north and west
of the area with other activity rotating towards the northwest
from eastern/central Ohio associated with the next wave. This
activity will pose the main concern mid evening into early Friday
with potential for pockets of moderate to heavy rain possible.
Before then expecting more of a hit and miss convective regime
with some potential expansion in the 21 to 00z window before
diminishing. Used HRRR experimental as it keyed in well yesterday
on convective development and has been overall decent today. May
need a further increase/expansion in pops given upstream trends
but for now have held no more than likely pops.
Coverage will increase even further Friday as strongest wave rotates
around the upper low and it moves back north across the area. Severe
weather not anticipated but could see some small hail with the
stronger cells.
&&
.LONG TERM...(Friday Night through Thursday)
Issued at 237 PM EDT Thu Sep 29 2016
Deep upper low will final begin to make a trek back towards the
north into Ontario Sunday and eventually New England by Tuesday.
Several pieces of energy will still be rotating around the low to
bring periodic chances for showers (storms?) into Saturday with
trends finally heading towards drier conditions Sunday and
especially Monday through Wednesday. While convection will mainly
be diurnally driven Sat afternoon/eve chance will exist just about
anytime so will maintain chance or slight chance pops outside time
frames with greatest potential.
A period of above normal temperatures will arrive with highs well
into the 70s through Wednesday as yet another trough digs into the
Plains with models differing on exact handling and timing as what
will likely be Hurricane Matthew may be raising havoc with the upper
level flow mid to late week. Slight chance to chance pops mainly
west Weds Ngt into Thursday as main dynamics remain to the west.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 810 PM EDT Thu Sep 29 2016
Stacked deep low pressure center over central Kentucky will
oscillate with a slow transition northward into far southern
Indiana by late Friday evening. First in a series of
circumferential channeled shortwaves to impact northern Indiana at
start of forecast period and expect a sharp drop in ceilings/shra
shortly and again another bout early Friday morning that should
saturate downward into predominately IFR primarily due to
ceilings. Cool/saturated airmass to likely lend very slow
improvement by midday and likely remain at or below fuel/
alternate levels for much of the daytime hours.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 6 PM EDT Friday for LMZ043-046.
&&
$$
SYNOPSIS...Murphy
SHORT TERM...Fisher
LONG TERM...Fisher
AVIATION...Murphy
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AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1050 PM EDT Thu Sep 29 2016
.UPDATE...
Issued at 1050 PM EDT THU SEP 29 2016
Showers continue to move NW across the Bluegrass and far eastern
KY and mean while the showers across the Lake Cumberland region
continue to diminish. The overall better coverage resides in the
Bluegrass where cloud tops actually cooled slightly this evening.
Therefore went categorical POPs in this region, and the HRRR
seemed to provide the best trend and initialization. However wane
these showers over the next 3 hours as models and analysis would
suggest including the HRRR. Also added patchy dense fog into the
grids and will be most prevalent in heavier showers and areas that
have seen more rain through the day. Other minor adjustments to
obs and trend will wrap up this update.
UPDATE Issued at 656 PM EDT THU SEP 29 2016
The more scattered coverage of showers and isolated storms
resides across the far east this evening and another area of just
showers across the Lake Cumberland region this hour. Between these
two areas is a relative lull and even clearing skies. This is all
being aided by a upper level low that is generally centered
across south central KY this evening. Overall think the forecast
package in the near term looks on track and will have to keep a
eye on radar trends through the night. Did opt to remove thunder
after 01Z, but kept in through then given the isolated strikes we
have seen in the far east toward Letcher and Martin Counties.
Otherwise only minor updates to latest obs and trends were
needed.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 440 PM EDT THU SEP 29 2016
19z sfc (and aloft) analysis shows a stacked low spinning over
Central Kentucky. This is clearly seen in the movement of the
scattered convection throughout the region as well as the clouds
on visible satellite. The convection was and is best developed in
far eastern Kentucky - particularly in RLX`s area where some
large hail has fallen. In fact, the storms to the east have been
well organized with decent low level rotation and evidence of
splitting cells. Will have to keep an eye on the far east and
northeast parts of the area into the evening. Temperatures did not
recover much from overnight lows today thanks to the clouds and
pcpn. At 3 pm readings varied from the mid 50s in the east with
the steadier rains to the lower 60s over the somewhat drier
Cumberland Valley. Winds have been light and variable through the
day with a tendency for them to come out of the north and
northwest while dewpoints have fallen into the low to mid 50s most
places.
The models are in good agreement aloft through the short term
portion of the forecast. They all depict a bowling ball of low
heights centered over Central Kentucky through midday Friday. This
feature will then meander back north to northwest into Saturday
morning. Plenty of energy accompanies the heart of the low and
will continue to spin over Kentucky. Late in the period there are
some differences starting to show up among the models with the
GFS the slowest to ease away from JKL and the NAM slightly
quicker. Given the similarities in guidance will favor a blended
solution with emphasis on the HRRR in the near term.
Sensible weather will feature a chilly and damp evening for most
with a potential for a couple of thunderstorms in the far east.
Some small hail cannot be ruled out from any stronger storm that
develop given the low freezing level. Fog will be possible
overnight and not just confined to the valleys as stratus is
expected to build down on the ridges, as well. Look for mainly a
few scattered showers around the fringes of the CWA later tonight
through Friday as the core of the upper low slips off to the west
and we start to dry out. Clouds will remain, though, limiting the
diurnal rise and fall through the rest of the forecast, but highs
should be a category or two higher than today.
Used the CONSShort and ShortBlend as a starting point for most
grids into Friday morning with the SuperBlend used thereafter.
Made only minor changes to the T grids based on our terrain. As
for PoPs - ended up similar to a MOS blend through Saturday
morning.
.LONG TERM...(Saturday through Thursday)
Issued at 325 PM EDT THU SEP 29 2016
The extended period should feature isolated rain showers to begin
the period Saturday and Sunday, as a slow moving area of low
pressure slowly rotates through the region. They system will have
only meager lift an moisture associated with it, so any showers that
form with it should be isolated to scattered at best, mainly for the
western and northern portions of the forecast area. Once the upper
low rotates out of the Ohio Valley and out of our area Sunday
evening, the remainder of the extended should be dry and pleasant. A
ridge of high pressure is forecast to settle over the region through
out the upcoming work week, which would bring mostly clear to partly
cloud skies, dry conditions, and light winds to eastern Kentucky.
Daily highs are expected to top out in the 70s for most locations. A
few spots along and south of the Hal Rogers Parkway and Highway
corridor may reach or slightly exceed 80 degrees Tuesday and
Wednesday. Nightly lows should bottom out in the 50s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 730 PM EDT THU SEP 29 2016
Starting out with lower CIGS at JKL,SYM, and SJS this evening and
western sites seeing VFR. Overall think areas that saw decent
rainfall today will stand the best chances for fog issues
overnight. Therefore went for a period of IFR VIS across site of
SYM and SJS. Other sites have been Trace and more hit or miss.
The other issue the forecast soundings would suggest the
potential for a stratus build down and therefore went at least
MVFR CIGs for all the sites. This will clear through the morning
on Friday as we get into the dry slot. Given the placement of the
upper level low winds will be light through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...DJ
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
928 PM CDT THU SEP 29 2016
.UPDATE...
Issued at 915 PM CDT Thu Sep 29 2016
Clouds will continue to rotate through our area for the rest of
tonight on the backside of the slow moving, deep upper level low
over KY. Scattered showers, mainly light were also moving through
parts of southwest IL and east central and southeast MO this
evening. Looking at the latest NAM and HRRR model runs it appears
that any showers late tonight will likely be confined to parts of
southwest IL. These clouds will help to keep the temperatures
from getting quite as cold as last night.
GKS
&&
.SHORT TERM... (Through Late Friday Afternoon)
Issued at 233 PM CDT Thu Sep 29 2016
Focus continues to low system over the OH Valley region.
This low will continue to linger in the area and actually move west
slightly thru Fri. Clouds will continue to spread across the area
tonight thru Fri with showers mainly east of the MS River. Latest
guidance continues to suggest a threat for thunder across far ern
portions of the CWA on Fri afternoon and have kept a slight chance
mention.
The extensive cloud cover will help to keep temps relatively warm
tonight and cool on Fri and have trended temps accordingly.
Tilly
.LONG TERM... (Friday Night through Next Thursday)
Issued at 233 PM CDT Thu Sep 29 2016
Models continue to have upper level low sit and spin over Ohio
Valley through first part of weekend, then begin to lift out to the
northeast Saturday night. So will have lingering precipitation
chances Friday night and Saturday in active cyclonic flow under
mostly cloudy skies.
Otherwise, temperatures to begin moderating for the last half of the
weekend and into early next week with highs in the mid to upper 70s,
maybe even low 80s for portions of the area by next Wednesday. In
the meantime, next system to approach the region by Wednesday, a bit
slower than previously forecast, so kept Tuesday night dry for
everyone now and lowered pops a bit on Wednesday. Best chances of
rain will be Wednesday night and Thursday as strong cold front moves
through.
Byrd
&&
.AVIATION... (For the 00z TAFs through 00z Friday Evening)
Issued at 552 PM CDT Thu Sep 29 2016
Nearly stationary upper level low and surface troughing was over
KY with an upper level ridge and surface ridging over the Plains.
Low level clouds along with a few light showers continue to rotate
through eastern MO and IL on the backside of the low. The MOS
guidance was consistent in lowering the cloud ceiling down to
around 1000 feet late tonight. The cloud ceilng should gradually
rise late Friday morning and afternoon, but not likely above
MVFR. More significant showers should remain east of the taf
sites tonight, with scattered showers for UIN and the St Louis
metro area Friday afternoon. N-nwly surface winds will continue
through the period.
SPECIFICS FOR KSTL: Nearly stationary upper level low and surface
troughing was over KY with an upper level ridge and surface
ridging over the Plains. Low level clouds along with a few light
showers continue to rotate through eastern MO and IL on the
backside of the low. The MOS guidance was consistent in lowering
the cloud ceiling down to around 1000 feet late tonight. The cloud
ceilng should gradually rise late Friday morning and afternoon,
but not likely above MVFR. More significant showers should remain
east of the taf sites tonight, with scattered showers for STL Friday
afternoon. N-nwly surface winds will continue through the period.
GKS
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 57 69 58 71 / 20 60 20 20
Quincy 54 67 58 69 / 10 30 30 30
Columbia 53 68 57 71 / 10 10 10 20
Jefferson City 53 68 57 71 / 10 10 10 20
Salem 54 67 54 70 / 40 60 40 20
Farmington 53 65 55 70 / 20 30 10 20
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service State College PA
526 AM EDT Fri Sep 30 2016
.SYNOPSIS...
Showery conditions will prevail today and tonight, especially
across the southern half of the state. Unsettled weather with
occasional light rain showers will persist through the weekend
with a gradual drying trend by early next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Two primary area of showers will continue through this morning,
mainly across southern and eastern portions of the forecast area.
The first plume of showers on a SE to NW axis across south-central
PA and the Laurel Highlands coincided with a strong 45 kt serly
LLJ, and enhanced upper level divergence/uvvel within the
thermally direct cell associated with the right entrance region
of a 90 kt/300 mb jet. The second area of mdt to hvy rain was
being created by a similarly strong, nearly 4 sigma, 40-45 kt
easterly 850 mb jet off the Atlantic transporting very high, 2-2.5
inch PWAT air over the coastal front.
Heaviest rainfall rates of 2-5 tenths of an inch per hour per
Dual Pol DPR product estimates are seen across the western Poconos
and portions of the Lower and Mid Susq River Valley.
The latest...07Z run of the HRRR tracks this area of enhanced
moderately heavy rain NWWD across the Middle and West branch
valleys of the Susq and north-central mtns during the mid to late
morning hours...before carrying it north of the PA/NY border by
14Z, leaving mainly scattered showers across the CWA for the
midday and afternoon hours.
Outside of these primary rain areas, look for overcast skies with
brief...scattered showers along with areas of drizzle and fog at
elevations AOA 1800 ft MSL.
Temps to start the day will be in the low-mid 50s in most
locations.
Winds will persist from the east to northeast at 8-12 kts.
The Large low will be quasi stationary and will continue to stream
moisture into Southwestern PA through much of today. Strong E-SE
LLJ and above normal PW along with associated forcing on
east/southeast side of upper low favors scattered to numerous
lighter rain showers through the period across the Laurels.
The highest rain chances this afternoon will once again be
focused across the SE half of the state, but should be generally
light and under 0.10 per hour, with 10-hour basin average amounts
mainly under 0.25 of an inch.
Afternoon max temps will only reach the upper 50s across the
higher terrain of the north and west...and lower 60s throughout
the valleys of central and southern PA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Greatest deep layer convergence appears to become focused across
the western mtns of PA tonight and early Saturday...before
shifting into Central PA for the late morning and afternoon hours
Saturday.
Expect to see rather low coverage of showers at any one time.
However, a few narrow north-south bands of mdt showers should
shift gradually east across the region during the day Saturday,
bringing additional light 12-hour rainfall amounts of 2 tenths or
less to many locations. A few locations could see over one half of
an inch where an hour or so of training showers occur.
Will follow the cooler EC and NAM guidance for max temps ranging
from the upper 50s across the higher...to mid 60s in the Susq
Valley on Saturday. GFS MOS guidance looks to be up to several deg
too warm considering solid overcast and persistent llvl easterly
flow.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
GEFS and latest operational models track the initially cut-off
upper level low slowly northward from the Lower Ohio Valley to
southern Lake Huron during the 12z Sat to 12z Sunday period.
The low will slowly blend into the upper level northwesterly flow
over Sern Canada Sun-Mon and cold air advection will filter into
the region early into next week.
The final vestiges of the low that has dominated our weather
pattern this week will finally slide off the New England coast by
the middle of next week thanks to an upstream amplifying trough
over the central CONUS.
High pressure should regain control of our weather here in PA for
Tue into early Thursday. The 00Z GEFS appears to be in close
agreement with the previous 12Z GFS and EC with a path of
Hurricane Matthew from the Bahamas to near the Outer Banks of NC
during the 12Z Wed to 12Z Friday timeframe. The main concern here
in Central PA would be a period of enhanced...deep easterly flow,
clouds and perhaps a few periods of rain late next week...before
the storm begins to drift NE and away from the Carolina and Mid
Atlantic Coast.
Temperatures will be slightly below normal through the weekend,
before shifting to slightly above normal by the middle of next
week...then possibly dipping back to near normal as clouds (at
least the mid and high variety) thicken-up to the NW of Matthew.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
Widespread MVFR-IFR conditions through tonight. Periods of rain
moving SE-NW across the airspace early today with decreasing
coverage by afternoon. Isolated LLWS possible 35-40KT from 090-120
degrees especially KBFD/KJST and may add with 09z update.
Outlook...
Sat...MVFR-IFR cigs. Ocnl -RA.
Sun...MVFR cigs. Chc -RA.
Mon-Tue...Gradual improvement likely.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Lambert/Steinbugl
AVIATION...Steinbugl
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
317 AM EDT FRI SEP 30 2016
.DISCUSSION...
The regional radar show another round of showers advancing across
much of the forecast area this morning. Recent radar trends indicate
that the intensity and thus rainfall amounts through the morning
rush hour will be much less than what occurred yesterday. This next
round of rain is still associated with the quasi stationary upper
low centered over Kentucky. The water vapor loop indicates good
upper difluent flow across the upper Ohio Valley and eastern Great
Lakes. There is also strong transport of Atlantic moisture extending
from the Mid Atlantic region into the eastern Great Lakes. These
factors are supporting the extensive swath of showers from Se Mi all
the way to wrn Virginia.
During the course of the day, the center of the upper low is
forecast to only inch up toward the Indiana/Kentucky border. A
strengthening of the cyclonically curved upper jet max to the east
of the mid level circulation (across the Upper Ohio Valley) is
forecast to increase upper divergence across Se Mi. This will then
trigger an increase in mid level deformation across Srn Lower Mi.
Model cross sections do show a rather deep layer of weak elevated
convective instability with respect to a saturated air parcel. This
does suggest the potential for the development of a rather deep mid
level frontal circulation. The main forecast uncertainty at this
point is the location of the more persistent mid level frontal
forcing and thus heaviest rainfall today. The NAM and GFS continue
to suggest this mid level frontal circulation focusing the more
persistent rainfall from the northern Detroit suburbs up through the
I-69 corridor into southern Saginaw county this afternoon into the
evening. The HRRR and especially the ARW suggest the frontal
dynamics will become established a little farther south (Metro
Detroit/Ann Arbor south to the Ohio border). Given the compact
nature of the upper low, it certainly seems possible for any mid
level frontal forcing to set up farther south closer to the mid
level low center.
So it seems possible for locations (generally south of a Saginaw to
Bad Axe line) to pick up another half inch to inch of rain, with
a few locals receiving up to an additional two inches of rain.
For this reason and and with some uncertainty where any nearly
stationary bands of more moderate rain will set up later today, the
current flood watch will remain intact.
The upper low will inch its way northward across Indian tonight. The
upper level divergence and better mid level frontal dynamics will
slide to the west of the forecast area, while the feed of the
Atlantic moisture fractures. This will lead to decreasing chances
for showers during the night. While there is of course some slight
differences amoung the 00Z model suite in the exact track of the
upper low, they all suggest it will lift into srn Lower Mi on
Saturday, then slowly depart to the east of the region Sunday into
Monday. The associated cold pool aloft and resulting steep mid level
lapse rates will reside over the forecast area Sat into at least
early Sunday. This will support some redevelopment of showers and a
few thunderstorms. The potential for deep convection within close
proximity to the slow moving upper low could certainly support some
additional localized heavy rainfall Sat into Sun. Ample cloud cover
and showers will maintain a low diurnal spread in temps over the
next three days (highs in the 60s and lows in the 50s). The
departure of the upper low will bring drier and warmer conditions to
the region for the first half of next week.
&&
.MARINE...
Stalled low pressure system south of the Great Lakes will maintain
persistent fresh onshore flow into Saturday morning. This will
warrant continuation of existing Small Craft Advisories for all
nearshore zones due to both winds and elevated waves. Easterly winds
will diminish in intensity and back to the northeast by the end of
the weekend as the low begins to lift out of the area.
&&
.HYDROLOGY...
The pattern today will remain largely unchanged from yesterday.
Rounds of showers will continue to pivot around a stalled low
pressure system with additional rainfall totals of 2 inches possible
on a local basis, including in the Detroit Metro area. The heaviest
rain is forecast to fall between noon and 6pm today, mainly along
and south of the I-69 corridor. Urban and small stream flooding will
once again be possible along with minor flooding on area rivers.
&&
.PREV DISCUSSION...
Issued at 1158 PM EDT Thu SEP 29 2016
AVIATION...
IFR ceiling will be widespread over SE Michigan during the night and
through the morning. This will be mixed with mostly MVFR restriction
in rain showers as they increase in coverage from Ohio. Nightfall
and infusions of moisture into the boundary layer from rain will
promote persistence of the low ceiling. MBS will have the best
chance to waver between IFR and MVFR within the farther north
reaches of the low pressure system and where the frequency of rain
will be lower until later in the day. IFR visibility will be more
dependent on coverage and duration of heavy rainfall as the surface
wind will remain moderate from the east and prevent much fog
component. Determination of coverage and duration of heavy rain
remains a challenge to pin down outside of the 0-3 hr time range in
this type of low pressure system. This is also the case for
otherwise low thunderstorm potential which will remain out of the
initial forecast and defer to later updates as needed. Ceiling and
visibility conditions are expected to progress upward into MVFR
assuming modest daytime heating during the afternoon will be
sufficient to lift ceiling outside of heavier showers.
For DTW... Ceiling on the cusp of IFR during the evening will settle
below 1000 ft during the night and remain there through the morning.
Visibility restriction remain mostly above 3 miles in moderate
showers. The main concern in the absence of thunderstorms will be
continued moderate northeast wind that will force traffic operations
to the northeast through Friday evening.
//DTW Threshold Probabilities...
* High for ceiling 5000 ft or less through Friday evening.
* Low for thunderstorms through Friday evening.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Flood Watch through this evening FOR MIZ060>063-068>070-075-076.
Lake Huron...Small Craft Advisory until midnight EDT tonight FOR LHZ422.
Small Craft Advisory until 5 AM EDT Saturday FOR LHZ421-441>443.
Lake St Clair...Small Craft Advisory until midnight EDT tonight FOR LCZ460.
Michigan waters of Lake Erie...Small Craft Advisory until midnight EDT tonight FOR LEZ444.
&&
$$
DISCUSSION...SC
MARINE.......JVC
HYDROLOGY....JVC
AVIATION.....BT
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Flagstaff AZ
1005 PM MST THU SEP 29 2016
.SYNOPSIS...Chances for showers and thunderstorms continue across
northern Arizona on Friday. Drier air is expected this weekend,
followed by increasing southwest winds and cooler temperatures
from a passing weather system early next week.
&&
.DISCUSSION...Showers and thunderstorms have decreased across
northern Arizona this evening. Will trim back POPS for eastern
sections tonight. HRRR and NAM12 do show more development across far
northwest Coconino County later tonight so will leave forecast alone
over the Kaibab Plateau.
&&
.PREV DISCUSSION /433 PM MST/...Satellite and radar imagery reveal
decreased shower activity and cloud cover across most of northern
Arizona south of Interstate 40. The remaining activity is expected
to decrease in intensity while dissipating from south to north
through the evening and overnight hours. With that said, some storms
may persist in the White Mountains region into the overnight hours
from convection moving northward from Graham and Greenlee counties.
On Friday, drying conditions are forecast behind a passing trough.
The forecast continues to call for chances of thunderstorms, but
coverage is expected to be considerably less than today. Over the
weekend, expect near average temperatures and dry weather as
southwest flow develops ahead of a deep low pressure system
approaching the west coast.
Models continue to indicate that a west coast low will pass north
of Arizona on Monday, pushing a cold front across the state.
Winds along and ahead of the front could become strong with gusts
40+ mph a possibility. Most of the moisture with the system
appears that it will stay north of the state at this point with
only low PoPs for our forecast area. Daytime highs early next week
should be around 10 degrees below average. Overnight lows have the
potential to be the coldest we have seen so far this season,
especially if overnight winds are able to diminish. Some areas
above 6000 feet could see the first hard freeze of the fall
Tuesday or Wednesday mornings.
&&
.AVIATION...For the 06Z package...Any remaining -shra/-tsra north
of KGCN and east of KSOW will dissipate by 07z-08z. Mainly clearing
skies overnight, patchy sc with bases 7-10kft agl. Patchy low clouds
and fog possible over higher elevation through 12z-14z. After 16z
Friday, expect sct-bkn cigs with bases from 8-10kft agl and isold
-shra/-tsra. Aviation discussion not updated for TAF amendments.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MAS/RR
AVIATION...BEP
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
335 AM EDT Fri Sep 30 2016
.SYNOPSIS...
A dry southwest flow of air will linger across the region through
this weekend. Progressively warmer temperatures are on tap through
early next week. The path of tropical cyclone Matthew will be
closely watched as it tracks north near the Atlantic coast next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Occasional convection continues to fire in the warm sector and move
N/NE early this morning, mainly near and east of the I-77 corridor.
Some of the cells have been quite strong and/or heavy rain
producers. This activity has been supported by a mid-upper level
speed max digging into the base of the trough extending from upper
low centered over the Ohio Valley. There`s been enough of an
eastward component to cell motion that training hasn`t been much of
an issue, yet. The latest mesoscale guidance suggests some semblance
of convective coverage will persist through daybreak. In fact, the
latest HRRR depicts an uptick in coverage around 12Z. Pops have been
increased to solid chance along much of the I-77 corridor through
sunrise. We aren`t expecting a whole lot out of this activity, but
will certainly need to watch for the training potential, especially
in the urban corridor along I-77.
The aforementioned speed max is expected to lower heights enough
such that the frontal boundary should finally nudge east of the
forecast area by early afternoon, spreading much drier air into the
NC Piedmont and northern foothills. Thus, deep convection in the
near term is expected to peak around daybreak, then diminish through
the morning, with nothing expected this afternoon. Some of the
mesoscale and short term guidance tries to develop some ridge top
convection this afternoon, but forecast soundings look positively
hostile to convective development, so we`re not buying it. Max temps
are expected to be (finally) right around normal, except along the
I-77 corridor, where maxes of a category or so above climo are still
expected. With the dry air mass in place, all areas are expected to
see around to a little below climo min temps tonight.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
At 240 AM Friday: GFS and ECMWF indicate that the center of a H5
closed low will lift north across the Great Lakes region this weekend. The
mid level pattern across the region will likely feature a Bermuda
High and a trof from the Ohio River valley south to the Mississippi
Delta. Short range guidance shows that a dry slot associated with
the Great Lakes low will rotate across the western Carolinas. This
pattern should result in dry conditions and high temperatures
ranging from the mid 70s within the mtn valleys to the low 80s east.
On Monday, it appears that an asymmetrical mid-level omega block
will develop over the northern CONUS, with the ridge axis over the
Mid West and Great Lakes. TC Matthew is expected to be tracking
north near the eastern tip of Cuba by late Monday. Sensible weather
across the CWA will remain unchanged from the dry weekend. High
temperature are forecast to warm a degree or two over values reached
on Sunday.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
As of 250 AM Friday: The path of TC Matthew will gain most of the
attention through the extended period. Both the GFS and ECMWF
indicate that Matthew will track north, tracking parallel along the
Atlantic coast from FL to NC. To the west, the northern tip of a H5
ridge will reach the southern Appalachians, sourced from a high over
Mexico. To the north, another deep low is expected to organize
across the nrn plains. The pattern does not appear to be supportive
of heavy rainfall across the CWA, developing ahead or west of
Matthews track. I will keep the forecast generally dry from Tuesday
through Thursday. Temperatures are forecast to remain between 3 to 5
degrees above normal.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
At KCLT and KHKY, surface front remains virtually stalled just west
of the terminals early this morning, with plenty of low level
moisture in place. This creates the very real potential for another
round of fog and/or low stratus this morning. In fact, KCLT was
already reporting a low MVFR cigs at issuance time, and there`s
plenty of IFR cigs not too far away. Meanwhile, SHRA were near the
KCLT airfield at 0530Z (tempo`d through 07Z), and this may result in
mixing out the lower cigs, at least for a little while. Based upon
observational trends, as well as signals from the guidance, there`s
enough confidence to add a mention of IFR cigs at both terminals
later this morning, but enough uncertainty exists such that these
conditions will be handled largely with tempos. The front is
expected to finally punch through by late morning, so improvement to
VFR should be rapid, with VFR conditions persisting through the end
of the period.
Elsewhere: It`s now looking doubtful that earlier forecast
restrictions will materialize at KAVL. An up-valley wind of 5-10 kts
is expected to persist, which should keep temp/dewpoint spreads
around or above 5 degrees. Suppose a brief IFR cig still cannot be
ruled out (and this is hinted at in the forecast with a tempo for
FEW008/SCT020), but all restrictions have been removed from the
forecast. With drier air lingering behind frontal boundary, all
sites are forecast to see VFR conditions persist for the next 24
hours.
Outlook: VFR conditions expected in most places through the
beginning of next week as dry high pressure settles in over the area.
Confidence Table...
07-13Z 13-19Z 19-01Z 01-06Z
KCLT Low 55% High 93% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 85% High 99% High 100% High 100%
KHKY Med 70% High 92% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...NED
NEAR TERM...JDL
SHORT TERM...NED
LONG TERM...NED
AVIATION...JDL
Area Forecast Discussion
National Weather Service Wilmington NC
505 AM EDT Fri Sep 30 2016
.SYNOPSIS...
A stationary front will waver along the coast through this
weekend. Periods of showers with an isolated thunderstorm are
possible along this front. Weak high pressure will build in
early next week. Hurricane Matthew may bring increasing waves
by the middle of next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Friday...The expansive cutoff Low centered over
Kentucky will be the main show affecting the ILM CWA this period.
The latest HRRR, RAP and HiResWrf models, all indicate to a
degree, the current pcpn breaking out and further increasing in
coverage and intensity during early this morning and continuing
thruout the day. This a result of dynamics from elongated mid-
level vorts from the tropics passing nearly overhead, the sfc
frontal boundary aiding low level forcing, and copious amounts of
moisture with flow from the sfc thru aloft mainly southerly
straight from the tropics. With the days heating and sfc based
instability becoming available, convection should breakout
further. The dry slot/tongue rotating around the cutoff low, will
slowly push the pcpn toward the east whereas the individual
showers and storms will be racing to the north. The back edge of
this main area of pcpn should push just east of the ILM CWA by
early this evening. Locations especially west of the I-95
corridor, will actually see drier air and lower temps due to the
dry slot. How much of this drier air and lower temps work eastward
are 1 of the main challenges of this forecast. For the overnight
period, have left a low POP along the immediate coast, basically
in the vicinity of where the stalled frontal boundary ends up.
At this point, have indicated in the Hazardous Weather Outlook
that heavy rainfall from todays convection will have the potential
to produce temporary flooding especially susceptible areas having
experienced a good dose of rainfall during the past few days.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 415 AM Friday...The cutoff low begins to very slowly fill as
it lifts to the north reaching the Eastern Great Lakes by the end
of this short term period. The direct affect from this cutoff low
will lessen with time. Models in agreement with the stalled sfc
front lying along or just off the coastline of the Carolinas. And
the dry air extending just shy of the immediate coast. Thus the
challenge of fcsting daily sfc temps and dewpoints. The moist air
will extend from the stalled front and offshore. The main
baroclinic zone and associated convection, to lie offshore from
SW to NE, parallel to the Carolina coastlines. Have indicated low
pops for the immediate coast to account for any onshore movement of
pcpn each night, and any development along the stalled front
during each day. As for temps, stayed closed to a consensus
amongst the avbl Mos Guidance with a slightly higher bias for max
temps each day. This will result in daily max temps a category
higher than climo norms and daily Mins 1 to 2 categories above the
norms.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 3 AM Friday...Temperatures will be quite seasonable to
slightly mild and rain chances minimal through the long term.
Moisture associated with frontal remains lingering offshore on
Monday and low level onshore flow could advect the stray shower to
mainly coastal areas. Weak upper troughiness may aid the coverage of
showers even though mid levels probably dry. Beyond Monday this
troughiness gets replaced by a slowly amplifying ridge and this
should cut down on the already paltry radar coverage. This low
coverage will be confined to coastal areas while inland zones stay
dry. Low level moisture trapped beneath the inversion will favor a
bit more in the way of clouds than `normal` through the period.
Currently it appears that Matthew stays far enough east to only have
marine effects locally. The GFS has been a very fast outlier from
other guidance though now Canadian is even faster. The EC has
shifted a bit farther east from previous runs. The overnight RI is
allowing convection to wrap around the center and so models may show
some improvement with the system stacking in the vertical.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
As of 06Z...Patches of IFR or lower now becoming less widespread
ahead of approaching pre-frontal band of showers and should remain
so for the rest of the overnight save for perhaps LBT where so much
rain fell recently. Showers streaming onshore to increase in
coverage predawn but only tend to MVFR with any IFR dips too brief
to warrant being in TAFs. Dry slot sweeps west to east across the
area this afternoon and clears things out. Slight chance of very
minor visibility restrictions returning Friday night.
EXTENDED OUTLOOK...Primarily VFR. Isolated to scattered afternoon
showers through much the period, although limited in strength and
coverage due to dry air aloft.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Friday...Sfc cold front across the inland Carolinas
will push to the coast late tonight and likely stall along the
immediate coast or just offshore Sat and subsequent periods.
This will be the dividing line for pcpn coverage. East of the
front pcpn will be more numerous and potent, and west of the
front isolated in coverage. Looking at S winds at 10 to 15 kt
today and SW 10 to 15 kt tonight, with speeds lower within the
actual frontal zone. Significant seas will be a healthy 3 to
possibly 4 ft, and comprised of mainly wind driven waves at 4 to 6
seconds. An underlying 1 foot ESE ground swell at 10-11 second
periods will be present.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 415 AM Friday...This time period will feature a stalled
frontal boundary either along the immediate coast of the Carolinas
or just offshore and parallel to the coastline. Thus the challenge
of either keeping winds from the S-SW or eventually having winds
become nearly variable in direction during this period. As
always, will try to acknowledge a dominate wind direction in lieu
of going variable. The sfc pg remains rather semi-relaxed thruout
this period, yielding either 5-10 kt or 10-15 kt. The latter will
occur at the beginning of this period and becoming 10 kt or less
as this period progresses. Significant seas will run around 3 ft
thruout this period. Wind driven wave input into the significant
seas will lower during this period. However, an easterly 2 to
possibly 3 foot ground swell at 10 to 12 second periods will
become the dominate input into the significant seas equation
during the day on Saturday and persisting thru Sunday night.
This illustrated nicely by Wavewatch3.
LONG TERM/MONDAY THROUGH TUESDAY/...
As of 3 AM Friday...A northeasterly wind wave and increasing ESE
ground swell energy to cause a gradual rise in seas over the long
term. Tough to say how high the wind speed and resulting short
period seas get though as most model guidance is seemingly too
fast with Matthew. Winds may end up being reduced this period
assuming the slow movement of the currently favored EC model comes
to pass. The aforementioned swell energy is less related to
Matthew and more energy from the long fetch developing. Any
Matthew swells (and there will be some!) may be slated for just
beyond the long term.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...MBB
NEAR TERM...DCH
SHORT TERM...DCH
LONG TERM...MBB
AVIATION...MBB
Area Forecast Discussion
National Weather Service Northern Indiana
310 AM EDT Fri Sep 30 2016
.SYNOPSIS...
Issued at 310 AM EDT Fri Sep 30 2016
A stalled upper level disturbance will bring periods of rain to the
area through the weekend. A few embedded thunderstorms are also
possible. Highs through the weekend will be in the 60s with lows in
the 50s. High pressure will bring slowly improving conditions early
next week.
&&
.SHORT TERM...(Today and Tonight)
Issued at 310 AM EDT Fri Sep 30 2016
Latest water vapor imagery clearly shows cutoff upper low
continues to wobble just south of our area, allowing continuous
feed of Atlantic moisture and shortwaves embedded in deep cyclonic
flow to maintain areas of rain and abundant clouds across the
southern Great Lakes. SCT/NUM showers will continue through at
least Saturday along with mostly cloudy skies and limited diurnal
temp ranges. Position of upper low continues to favor main axis of
steadier/heavier rain across southern Michigan where best
850-700mb theta-e ridge resides, along with better 295K system
relative isentropic ascent, midlevel deformation, and upper level
divergence. There is also a secondary area of fgen/deformation
across central IN/OH on immediate northern flank of cyclone.
Current regional radar mosaic shows these axes of better forcing
and moisture quite well and will continue to pivot eastward this
morning. Even outside of these two areas, the chance for SCT
showers will exist throughout the CWA given abundant moisture and
deep cyclonic flow. Best chances for most of the area will
probably be this afternoon and into the evening/early overnight.
Height fall centroid will begin to lift north during this time
given slow approach of west coast trough. Combination of robust
midlevel CVA and increasing instability due to cold pool aloft
will likely support numerous/widespread showers. A few embedded
thunderstorms certainly possible given around 500 J/kg of SBCAPE
during diurnal peak. Chance of thunder could even persist after
sunset given surface dewpoints around 60F and 500mb temps dropping
below -20C. No severe weather is anticipated. Locally
moderate/heavy rain may be possible if weak instability is
realized and any training develops with PW values around 1.25
inches and decent synoptic forcing, but not expecting any real
impacts. Basin-average QPF amounts expected to be around 0.25-0.5
inches through tonight. Expect high temps to remain in the
mid/upper 60s (assuming no breaks in the clouds) with lows tonight
generally in the mid 50s.
&&
.LONG TERM...(Saturday through Thursday)
Issued at 310 AM EDT Fri Sep 30 2016
Midlevel cold pool will be directly overhead on Saturday and this
will support another day of showers, and possibly thunderstorms,
given 500 J/kg SBCAPE and pinwheeling vort lobe overhead. Best
chances will likely be in the afternoon, during peak heating, but
again, no severe weather is expected given limited instability.
Activity will diminish overnight as instability wanes and upper low
begins to lift NE. Precip chances are lower on Sunday but can`t
completely rule out shower chances as several models indicate weak
vorticity spoke rotating through the area on backside of exiting
low. Deep/moist cyclonic flow will at least support mostly cloudy
skies and a few stray showers certainly possible in our N/NE
counties. Some peaks of sun possible in our south and could see some
lower 70s for max temps.
Improving conditions expected during the first half of next week.
Monday appears mainly dry, though still some residual cyclonic flow
so could still be a fair amount of clouds and a very low chance for
a sprinkle in our north. Ill effects of upper low will be fully
vanquished by Tuesday as longwave ridge develops over the Great
Lakes in response to deep trough over the Rockies/Central Plains.
Eventually this will send a cold front through our area but likely
not until Wednesday night/Thursday with questionable precip chances
based on latest GFS. Until then, expect slowly moderating temps and
mostly sunny conditions Tues and Wed.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1237 AM EDT Fri Sep 30 2016
Widespread mvfr/ifr conditions over nrn IN and upstream across srn
MI/nw OH attm. Not expecting any sgfnt improvement to conditions
early this morning, with upstream cigs/vsbys suggesting some
potential for further deterioration. Ocnl areas of shra should cont
to rotate around strong upr low now centered over nrn KY and fcst to
lift slowly north today/tonight. Some diurnal improvement to flight
conditions psbl today, but latest HRRR suggests another band of shra
will move through the area this aftn suggesting any improvement will
be fairly brief.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 6 PM EDT this evening for LMZ043-046.
&&
$$
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...JT
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Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
332 AM CDT FRI SEP 30 2016
.SHORT TERM...(Today and tonight)
Issued at 332 AM CDT Fri Sep 30 2016
Cut-off H5 low that drifted down into KY yesterday is already
starting to lift back to the NNW this morning. Biggest implication
for us is that the low stratus looks to return from the east faster
than initially indicated, with sky grids increased considerably this
afternoon in western WI/eastern MN and overnight for western MN. 925-
850 RH off the GFS/NAM/RAP shows cloud cover currently over SE WI
ending up in eastern SD by Saturday morning. Of interest though is
that the NAM in particular shows a wedge of dry air dropping down
from Lake Superior tonight, with skies actually clearing out some in
western WI tonight as the stratus is heading for SD. Given the
expected cloud cover, low 70s are unlikely again today out in
western WI.
Other issue more for this morning is a batch of low stratus coming
down off of Lake Superior. The HRRR shows this cloud cover getting
down to about the Twin Cities/Wilmar in the for of fog/low stratus.
Though this may result for a cloudy morning for much of central MN,
this looks to mix out by mid-late morning with a brief window of
sunny skies in the afternoon before cloud cover arrives from the
east.
Last change made in the short term was to keep the Eau Claire area
dry through 12z Saturday. CAMs and deterministic models alike keep
the MPX area dry, with any rainfall Friday night confined to eastern
WI where moisture on the 290-305k isentropic surfaces.
.LONG TERM...(Saturday through Thursday)
Issued at 332 AM CDT Fri Sep 30 2016
The period begins with a stubborn upper level low lifting slowly
northward across Indiana. Considerable cloudiness will occur
across the FA in the morning along with a few showers from the
southeast corner of MN through KEAU. The cloudiness should begin
to breakdown from the northeast in the afternoon as drier air
spreads in along with the upper level low beginning to drift east.
This leaves a horseshoe of higher cloud cover curving from
western MN through IA to eastern WI. The cloudiness will breakdown
Saturday night leaving us with a fine early fall day on Sunday.
High temperatures this weekend will be very close to seasonal
values with lows about 5 degrees above normal.
We have had a little bit of a roll reversal for next week between
the EC and GFS with regards to the weather system impacting the
FA in the Tuesday through Thursday period. The EC continues to
inch forward a bit on the leading edge of the rain on Tuesday
while the GFS is looking more like earlier runs of the EC on
keeping rain out of the Twin Cities until Wednesday afternoon. The
Canadian would also keep rain out of the local area until
Wednesday afternoon.
One of the differences noted is that the EC has more of a
positively tilted upper wave while the GFS and Canadian are more
negatively tilted. At this point, we allowed small pops into
western MN on Tuesday with the small pops working across eastern
MN and western WI Tuesday night. This will be too fast if the
latter solutions are correct. Another item noted is the strength
of the low level moisture transport Tuesday night and early
Wednesday across western MN. This area will likely see the most
rain from this event with amounts of a half inch to one inch
likely. The long term closes out with a cold front pushing east of
the FA with a breezy southwest wind occurring on Thursday.
High temperatures early next week will continue to be close to
seasonal normals. However, highs will trend downward thereafter,
with readings only in the middle 50s to lower 60s expected on
Thursday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1143 PM CDT Thu Sep 29 2016
Mainly clear skies and light winds are expected for the first half
of tonight, but we are watching an area of low stratus that is
starting to expand west-southwest. It is most likely at KSTC and
KAXN...but also possible at KMSP and KRNH. 300-600ft ceilings are
being observed with these clouds.
KMSP...
We are changing are tune about a clear morning. The low stratus in
northern WI and northern MN is making good progress W-SW, and
these 400-700ft ceilings could be close or over KMSP by sunrise
if the trends continue.
/OUTLOOK FOR KMSP/
Sat...VFR. Wind ENE at 5 kts.
Sun...VFR. MVFR possible. Wind NE at 5 kts.
Mon...VFR. Wind SE at 5-10 kts
&&
.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...RAH
AVIATION...CLF
Area Forecast Discussion
National Weather Service Morristown TN
326 AM EDT FRI SEP 30 2016
.SHORT TERM (Today and Tonight)...
The main feature throughout the short-term forecast will be the
upper level closed low currently centered across Central Kentucky.
At the surface, a boundary exists to the east of the mountains
across W NC and SW VA. Dewpoints to the east of this boundary are in
the upper 60s and low 70s and to the west in the 40s and 50s. The
highest dewpoints across the forecast area are in locations closest
to the boundary across Northeast Tennessee and Southwest Virginia.
Already seeing a few locations reporting fog this morning with low
dewpoint depressions across the area. Patchy fog is expected to
continue to develop throughout the early morning hours. Current
radar imagery indicates a few showers moving across Northeast
Tennessee and Southwest Virginia early this morning and have kept
at least a slight mention of precipitation for these area
throughout the early afternoon. The latest HRRR indicates an uptick
in precipitation across North Carolina later this morning. Most of
the activity is expected to stay to the east where the higher PW
air is but expect the moisture gradient will be right along the CWA
border. Most of the area will remain dry today as the upper low
drifts to the north. Highs will be slightly below normal ranging
from upper 60s to mid 70s. Dry conditions will continue overnight
with the surface boundary well to the east of the area. Cool
conditions are expected overnight with lows in the upper 40s to mid
50s.
.LONG TERM (Saturday through Thursday)...
As an upper low slowly pulls away from the area this weekend...a
stray shower may brush across our far northern Cumberland Plateau
area Saturday afternoon. Otherwise...high pressure builds into the
region and will be the main weather feature throughout the
extended. This will result in a quiet weather pattern with dry
conditions and valley temperatures warming back into the 80s for
the upcoming work week. Could see a weakening frontal boundary move
through late in the period. Models differ on the amount of moisture
and energy attached to the system. For now will only mention slight
chance of showers over portions of northern locations around the
Thursday time frame. Additionally...of concern is a tropical system
potentially moving along the east coast late in the extended.
Confidence quite low on track of this system and will continue to
monitor but for now...current model trends show track will have
little effect on weather across the Southern Appalachian Region.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 74 56 79 57 / 10 10 10 10
Knoxville McGhee Tyson Airport, TN 73 52 76 54 / 10 10 10 10
Oak Ridge, TN 73 53 76 55 / 10 10 10 10
Tri Cities Airport, TN 72 49 74 51 / 10 10 10 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&
$$
MA/MJB
Area Forecast Discussion
National Weather Service Blacksburg VA
344 AM EDT Fri Sep 30 2016
.SYNOPSIS...
A strong upper level area of low pressure will remain just west of
the mountains today before slowly lifting to the north later
tonight into Saturday. This system will combine with a residual
stationary front across the region to produce periods of showers
and thunderstorms into late tonight. The low will move northeast,
away from the region, resulting in drier weather this weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 245 AM EDT Friday...
Broken bands of heavy rain producing showers continue across the
west under the tail of a passing speed max and over the northeast
third with added low level convergence early this morning. Expect
this trend to persist through daybreak with main coverage likely
shifting into the northwest sections as multiple short band type
features merge. Then questions with added coverage through the day
as the upper low begins to shift back north while the jet aloft
remains strong over continued low level convergence espcly north
and east this afternoon. Will also have to watch for another band
to work north along the southern Blue Ridge this morning as
several solutions including the latest HRRR and 00z ECMWF paint
quite a bit of QPF extending north from the North Carolina
foothills into the west between 12-16z. This along a residual
convergence axis well to the south and eventually along the
eastward moving occluded front that will swing across the Blue
Ridge this afternoon. This along with some breaks and decent
instability southeast may allow one final heavier band of
shra/tsra to evolve across the north/east this afternoon given
strong veering with height and moist PWATS. However with
uncertainty wont hoist another watch at this point while allowing
the ongoing FFA to end with this package given only current
scattered nature to shra attm.
Otherwise again running with likely/cat pops today, except tapering
to chance heading into the southwest zones where will likely
remain in the dry slot aloft with limited added showers. Lowered
high temps a little under easterly flow and more clouds as
expecting a range from near 80 southeast to only the 60s far west.
Upper low should continue to trudge north toward the Ohio Valley
overnight allowing drier air aloft to gradually win out from
southwest to northeast behind the passing surface occluded
boundary. Think still decent coverage in the north/east during the
evening before showers fade late tonight with little focus
remaining. May even see some clearing work in from the southwest
after midnight so mostly chance pops tapering to spotty showers
northeast sections by dawn. Expect more clearing west to allow
temps to fall into the cool 40s in spots with overall low/mid 50s
elsewhere, except low 60s far east.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 305 AM EDT Friday...
Drying trend will continue over the weekend as the upper low
finally lifts farther north and weak high pressure slides in from
the west. May still have an isolated shower around early Saturday
over the north, otherwise cutting pops with more sunshine on tap
by the afternoon. Another spoke of energy looks to rotate around
the upper low Saturday night with this feature reaching the
western mountains later Sunday. Moisture quite limited with the
weak associated front but cant totally rule out an isolated shower
western slopes late Sunday into Sunday night. Otherwise expecting
mainly clear skies Saturday night and mainly sunny Sunday before
clouds invade the west late. High temps to remain mild under
west/southwest flow aloft with mostly 70s both Saturday and Sunday
and lows mostly 50s Saturday night given good radiational cooling
conditions.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 330 PM EDT Thursday...
The upper low will give way to ridging in the eastern US through the
early part of next week. This stall the approaching front and allow a
large area of high pressure to settle over New England and wedge down
the east side of the Appalachians. The big variable lies with the
potential track of TS Matthew as it is expected to turn north and move
up the Atlantic coast. The exact track of Matthew will determine how
much, if any, precipitation it can push into the region from the east
and how much overrunning precipitation will develop as it interacts
with the wedge. Right now, the most likely scenario is for some light
overrunning precipitation to develop by Tuesday and increase a bit into
Wednesday especially in the east, with any significant effects form
Matthew remaining to our east.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
As of 1250 AM EDT Friday...
Variable but overall sub-VFR conditions will prevail overnight
with cigs fluctuating between MVFR and low end IFR at times. Best
coverage of showers resulting in vsby restrictions look to occur
along the KLYH-KHSP corridor for the rest of the night. However
another narrow band of showers and storms may affect areas from
KBLF to KBCB/KROA into the early morning hours. Thus will include
either a vicinity or tempo mention with perhaps a brief prevailing
group of lower cigs/vsbys. Should finally see convection wane
before daybreak but still enough to keep thunder in a few western
sites over the next few hours.
Uncertainty continues with the degree of added convective coverage
on Friday with the upper low starting to retrograde while the
occluded boundary to the west shifts east and starts to cutoff
deeper moisture late. Models continue to focus showers and storms
across the northwest corridor Friday morning, then along and
north of a KLWB- KDAN line. Should see any IFR conditions slowly
improve to MVFR/VFR by midday/early afternoon though think places
like ROA/LYH/LWB will keep MVFR to the end of this taf period.
Will include more showers and storms given decent probability
during the afternoon in most locations with tapering of showers
by the evening as the main corridor of deeper lift slides north.
Extended aviation discussion...
A deep upper low will finally shift farther to the north by
Saturday and away from the region on Sunday. This should allow for
a gradual improvement in cigs after early sub-VFR Saturday with
widespread VFR Sunday as weak high pressure builds in. Looks like
overall VFR to then prevail into early next week outside of some
upslope low clouds Monday and perhaps along the Blue Ridge Tuesday
as another weak wedge develops under high pressure to the north.
&&
.HYDROLOGY...
As of 330 AM EDT Friday...
Overall convective bands have decreased in both coverage and
intensity early this morning so letting the watch go across the
north for now. Otherwise main concern again with the redevelopment
of heavier bands from the south/southeast through the day as
multiple areas of convergence pivot around the upper low to the
west. Likely looking at another inch or so of rainfall on average
across the north with locally higher amounts where deeper
convection mixes in. Also some concern along the Blue Ridge
through midday with possible very early morning redevelopment and
training as seen a few models. Given now saturated soil conditions
and elevated stream/creek levels will be easier for flooding or
flash flooding to develop while still appears most mainstem rivers
will stay below flood levels for now.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM...MBS
AVIATION...AMS/JH/WP
HYDROLOGY...JH
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
319 AM CDT FRI SEP 30 2016
.SHORT TERM...(Today and tonight)
Issued at 319 AM CDT Fri Sep 30 2016
Main features undergo minor changes today and tonight and bring some
forecast difficulties by late tonight. Upper low over the Ohio
Valley looks to lift a bit north with the low level ridge over the
Missouri Valley weakening somewhat. This should allow for slightly
more cirrus to reach eastern Kansas with time with the airmass
modifying a bit for slightly warmer high temps today. The ridge
weakens enough for winds off the surface to go more easterly this
evening, bringing the potential for the low cloud over eastern
portions of Iowa and Missouri early this morning to make their way
into northeastern Kansas late this evening. Models are in good
agreement with these trajectory trends and bring a decrease in
speeds late in the night. Depending on where the stratus ends up and
how far east and persistent the cirrus will be, at least patchy fog
seems possible for mainly northeastern locations after 08Z.
.LONG TERM...(Saturday through Thursday)
Issued at 319 AM CDT Fri Sep 30 2016
Saturday may see some patchy fog in northeast Kansas especially in
the lower elevations and river valleys. Surface ridge will be over
northeast Kansas Saturday morning with light winds expected and
clear skies. Highs on Saturday will mainly be in the lower to mid
70s across the area. Slightly warmer temperatures are expected on
Sunday with the return of southerly flow and rising heights. The
upper low in the Ohio Valley on Saturday will move off to the
northeast through Monday as an upper level trough move across the
western CONUS with a ridge over the Southern and Central Plains.
This will bring temperatures back into the lower 80s for Monday. By
Tuesday the upper trough will move out into the Plains with main
upper low moving northeast into the Northern Plains. Good
moisture return is forecast along with increasing shear and
instability. Best chances focus on Tuesday night into Wednesday for
thunderstorms. A cold front is forecast to move through central and
eastern Kansas on Wednesday as the upper trough moves across the
Plains. The upper trough axis looks to move through on early
Thursday. Expect precipitation to linger in the east Wednesday night
then dry out behind the front by Thursday morning. Cooler
temperatures in the low to mid 70s and lows in the 40s to lower 50s
Friday morning.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday)
Issued at 1129 PM CDT Thu Sep 29 2016
Forecast soundings prog any boundary layer moisture to remain very
shallow and the latest RAP soundings fail to saturate the surface.
Because of this will maintain a VFR forecast without adding a
mention of fog, but there may be a slight chance for some shallow
ground fog in the river valley.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...65
LONG TERM...53
AVIATION...Wolters
Area Forecast Discussion
National Weather Service Albany NY
1013 AM EDT FRI SEP 30 2016
.SYNOPSIS...
As a slow moving upper level low moves towards the area,
on and off rain showers are expected today through the weekend.
Along with plenty of clouds, temperatures will be a little cooler
than recent days. Some clearing is expected by the early to middle
part of next week once the slow moving storm system moves away from
the region.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Clouds have spread across the entire region and based on upstream
conditions, all areas should remain cloudy through the afternoon.
The steadier rain is still west of our region, from the Catskills
to the Tug Hill Plateau and southerly low level flow is steering
the rain almost due north. There are a few sprinkles and isolated
showers into the mid Hudson Valley, eastern catskills and western
Mohawk Valley. Radar and satellite data shows a very gradual
building east of the rain and some new development toward the mid
Hudson Valley that will track north and northeast through the
afternoon. So have adjusted rain chances and timing based on
current data and trends, with some HRRR forecast data
considerations as well. Some adjustments to sky cover and
temperatures, too, as temperatures are not likely to rise much
through the day. The previous AFD has a few more details and is
below...
Into the day today, there will be a chance for some light rain
showers, mainly across southern areas. Although the rainfall may
initially continue to fall as virga, the column should moisten up
enough for some showers to reach the surface. Decent warm air
advection/isentropic lift is expected to develop by later today,
which should allow for a more widespread and organized band of
showers to move up from the south by later this morning and into
this afternoon. The majority of these showers should be fairly
light in intensity, although cannot rule out some brief heavier
bursts by later today across far southern areas. While far
southern areas may pick up to a half inch of rain today, the bulk
of the region will see under a quarter of an inch.
High temps today will vary from north to south. While northern
areas may see highs in the low to mid 60s thanks to less precip
and thinner clouds, the rest of the area looks to see highs in the
mid 50s to low 60s.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
The upper level low will continue to sit and spin over the
Midwest/Ohio Valley tonight, keeping the stagnant upper level
pattern in place. Although the best isentropic lift will be
lifting northeast of the area by tonight, still cannot rule out
some light rain showers from time to time thanks to moist cyclonic
flow in place. With plenty of clouds in place, there won`t be much
of a diurnal range, with temps tonight only falling into the mid
40s to mid 50s.
During the weekend, the upper level low will only be slowly
shifting eastward. It looks to move to near to near Detroit by
Saturday Night and towards western New York by Sunday Night. As
it slowly starts to head our way, the upper level ridge axis will
also shift eastward and away from the area. Moist cyclonic flow
will continue to allow for additional showers from time to time
over the weekend. At this point, have mainly just gone with chc
pops, as it is rather difficult to pinpoint any particular
time/area more prone for showers.
With the persistent southerly flow in place, PWAT values will
continue to rise and reach near 1.50 inches (especially for
southern areas) on Saturday. As a result, any shower can briefly
have some heavier rainfall, but these rates won`t be high enough
to cause any flooding concerns and any bursts of heavier rainfall
should be relatively short lived.
Outside of any rain showers, it should be cloudy, damp and fairly
cool. Highs on Saturday look to be in the upper 50s to low 60s.
Lows on Saturday Night look to be upper 40s to mid 50s. Highs on
Sunday may be slightly higher with temps reaching upper 50s to mid
60s. Lows on Sunday night will be in the upper 40s to mid 50s.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
The long term forecast starts out unsettled on Monday and Tuesday
with fair weather expected for Wednesday and Thursday. Hurricane
Matthew is forecast to be about 500 miles southeast of the
Carolinas on Thursday so no local impact from Matthew expected during
this extended period.
Have continued the forecast of unsettled weather for Monday and
Tuesday with a chance of showers during the entire period. There is
good model consensus showing the persistent upper level low
near Lake Ontario on Monday and over southern New England on
Tuesday. Cyclonic flow, upper level cold pool and plenty of moisture
should conspire to produce occasional showers across the forecast
area. Highs on Monday generally in the 60s to near 70 with some
upper 50s in the higher terrain. Lows Monday night are expected to
be in the upper 40s to mid 50s with highs on Tuesday in the upper
50s to mid 60s.
Dry weather is then expected Wednesday and Thursday as a large area
of high pressure ridges in from northern New england. Highs on
Wednesday in the 60s to near 70. Lows Wednesday night are expected
to be in the 40s with highs on Thursday in the 60s to around 70.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Large, nearly stationary, low pressure system over Kentucky is
providing a deep southeasterly flow across the area. Main band of
rain stayed west of the TAF sites overnight, but should slowly
move eastward today. The combination of onshore flow and
precipitation should moisten the lower part of the atmosphere
later Today so this afternoon or evening expect MVFR Cigs/Vsbys
all TAF sites, which will continue through the overnight.
East to northeast surface winds are forecast to continue through
the TAF period /12Z Saturday/. Winds will generally be 5 to 10
knots, but there may be occasional gusts to 20 kts during the day
today.
Outlook...
Saturday through Monday Night: Moderate Operational Impact. Chance
of SHRA.
Tuesday: Low Operational Impact. Slight Chance of SHRA.
&&
.FIRE WEATHER...
Unsettled weather is expected over the next few days as a slow
moving upper level low moves across the area. As a result of this
storm, several days of cloudy weather is expected, with on and off
rain showers. The entire region is expected to see a wetting
rainfall through the weekend, with RH values each day generally
above 60 percent. E-NE winds of 5 to 15 mph are expected today and
tomorrow, with winds switching to the SE on Sunday at 5 to 10
mph.
&&
.HYDROLOGY...
The latest US Drought Monitor continues to show drought conditions
across much of the region. Precipitation departures this year have
been 3 to 12 inches below normal, with the greatest departures
across southeastern parts of the area. As a result, streamflow and
ground water levels have been running below normal.
Some needed rainfall is expected over the next few days, although
this rainfall will not be enough to end the drought by itself. A
slow moving upper level low will allow for on and off rain showers
through the weekend and possibly into early next week as a well.
Most locations will see at least a half inch of rainfall, with the
potential for over an inch across southeastern parts of the
region. Although rain may briefly fall moderate to heavy in
intensity, no flooding is expected.
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...Frugis
NEAR TERM...Frugis/NAS
SHORT TERM...Frugis
LONG TERM...SND
AVIATION...SND
FIRE WEATHER...Frugis
HYDROLOGY...Frugis
Area Forecast Discussion
National Weather Service Denver/Boulder CO
928 AM MDT Fri Sep 30 2016
.UPDATE...
Issued at 912 AM MDT Fri Sep 30 2016
showers this morning have moved further east on the plains than
indicated on the hrrr model...these showers will continue moving
slowly northeast...but will likely not drop much east of Sterling.
Hrrr suggests the activity will transition from the northern
plains today...to the palmer divide this evening with some
stronger convection also developing. this reflected in the
grids...will adjust pops a bit based on radar trends this morning.
&&
.SHORT TERM...(Today and tonight)
Issued at 424 AM MDT Fri Sep 30 2016
A stream of moist air is moving over the state this morning,
mainly over the mountains. Shower activity over the mountains
early this morning should increase through today as diurnal
warming helps the airmass become slightly unstable. Light radar
echoes have developed over the north central mountain counties,
but the heavier echoes so far have been over the west slope. The
moisture is moving over the state on deep south to southwesterly
flow as an upper ridge axis holds its position over western
Kansas. The southerly fetch will make it difficult for much
precipitation to move over northeast Colorado until later this
afternoon and evening. And even then, areas along the I-25
corridor may be the only ones to see any rainfall. The forecast
will have the highest chances of precipitation over the mountains.
By afternoon, the atmosphere may become unstable enough to support
thunderstorm activity, but only moderate rainfall is expected.
Temperatures today will be held back by the increasing cloud
cover, but still a couple degrees warmer than normal. Later
tonight, temperatures in the mountains will cool enough for snow
to fall at elevations above 8000 feet. Shower activity will be
winding down at that time, so no significant accumulations are
expected.
.LONG TERM...(Saturday through Thursday)
Issued at 424 AM MDT Fri Sep 30 2016
A flat upper level ridge will be over the area on Sat and will
become more swly on Sun as an upper level trough deepens over the
Pacific NW. There will be some mid lvl moisture over the rgn on
Sat with not as much on Sun. Over instability is not that great
either day with capes aob blo 500 j/kg. Overall the best chc of
convection looks to be on Sat over the higher terrain with only
isold activity over the plains. Temps will remain abv normal both
days with readings in the upper 70s to lower 80s across nern CO.
On Mon swly flow aloft will increase as an upper level low moves
into the Great Basin. Surface low pres will intensify east of the
mtns with gusty ssw winds expected over the plains with increasing
fire danger. Moisture will increase in the mtns by aftn mainly west
of the divide which will lead to a chc of showers and storms as some
mid lvl qg ascent moves in. As for highs temps will remain above
normal especially across nern CO as highs reach the lower to mid
80s.
For Mon Night into Tue the upper level low will move ene across WY
with the flow aloft becoming more wnw across nrn CO. Cross-sections
show best moisture will stay to the north of the area with downward
forcing in place. Will keep in a chc of showers mainly north of I-
70 across the higher terrain. Temps will be cold enough for some
snow in the mtns with a mix across the higher valleys. Over nern CO
will keep in a slight chc of rain showers. Winds will increase in
the foothills and across the plains as a bora type fnt moves across
late Mon Night into Tue morning. As for highs readings will drop
into the 60s across the plains.
By Tue Night into Wed the upper level low will move into the wrn
Dakota`s with wnw flow aloft remaining over the area. There are
some differences between the ECMWF and GFS with handling of
moisture. The GFS shows an increase in moisture Tue night into
early Wed morning while the ECMWF has this moisture increase late
Tue night thru the day on Wed. Overall should see a better chc of
snow in the mtns Tue night possibly into Wed depending on the
timing of this moisture as orographics will be favorable. Over the
nern CO will see a slight chc of showers. Winds will remain gusty
across the area as well. Highs over nern CO will remain in the
60s.
For Wed Night into Thu the flow aloft will continue wnw as drier air
spreads across the area. This should lead to a dry pattern with
temps warming back to nr seasonal levels.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 424 AM MDT Fri Sep 30 2016
Showers today will stay mostly north of the Metro area and over
the mountains...metro area aiports will have a slight chance of
showers after 21z. Will put vcts at kapa and kbjc vcsh at Kden.
Aviation impacts should be minimal...with mostly vfr ceilings and
spotty mvfr ceilings. Winds in the metro area will be light.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...RTG
SHORT TERM...Dankers
LONG TERM...RPK
AVIATION...Dankers
Area Forecast Discussion...Updated
National Weather Service Billings MT
927 AM MDT Fri Sep 30 2016
.UPDATE...
Shortwave moving through eastern MT this morning will generate
isolated showers and a few thunderstorms through the afternoon
over parts of the area. Expanded precipitation chances over
eastern zones late this morning/early this afternoon to cover the
path of the wave. CAPES on RAP soundings were 500 j/kg or lower
with no shear, but lapse rates were high today, so included a
slight mention of thunder in the afternoon. Kept some QPF over the
mountains through the day with orographic lift, the instability and
precipitable waters around /0.70/ inches. Precipitation will end
this evening. Temperatures were in good shape with mixing to
around 700 mb. Winds were higher than forecast in KLVM so have
increased wind speeds there. Arthur
&&
.SHORT TERM...valid for Tdy and Sat...
Shortwave lifting out of north central WY is producing some shower
activity near Billings and in eastern areas early this morning.
Though there has not been any lightning since evening, mid level
lapse rates remain steep at around 7.5c/km, and the airmass is
plenty moist (precipitable waters on the order of 150 pct of
normal), so isolated to scattered showers will continue and shift
east over the next several hours in response to the synoptic scale
ascent. Have expanded morning pops to account for the expected
shortwave timing. As showers end to our east we will see
subsidence spread over our west as main upper trof remains well to
our west and off the Pacific coast. Again per the moist airmass we
could see some weak showers/tstms develop over our western
mountains during the peak heating hours, otherwise it will be dry
today and tonight once forcing from the current shortwave exits.
Pacific shortwave will emerge from the western low and move thru
the northern great basin into western and central MT Saturday
afternoon and evening. This will bring our next period of showers
and isolated thunderstorms beginning in our west Saturday
afternoon and tracking eastward across the lower elevations after
00z with a frontal passage.
Temps will remain well above normal the next two days, but not
quite to record levels, as we remain under warm SW flow aloft.
Expect highs mostly in the upper 70s to mid 80s, along with mild
nights.
JKL
.LONG TERM...valid for Sun...Mon...Tue...Wed...Thu...
Models continue to prog an upper trough and associated low to
move onto the west coast on Sunday. As the trough and associated
low move inland, moisture and energy will be advected over the
region bringing increasing shower and thunderstorm chances through
the middle of next week. Much like previous model runs, the track
of the aforementioned low and location of the precipitation
remains somewhat uncertain. The GFS lifts the low out of the
Great Basin on Monday and through Wyoming on Tuesday, and
eventually off to the east into the Dakotas by Wednesday. The
ECMWF on the other hand is slightly different with the track of
the low. Like the GFS, the low lifts out of the Great Basin on
Monday, but takes the low on a quicker and more northern track,
lifting the low into southern Montana by Tuesday afternoon,
gradually moving into North Dakota by Wednesday evening. Shortwave
ridging is then progged to build in over the region for Thursday
and Friday bringing drier conditions to the area. The only
exception could be eastern areas where wrap-around precipitation
associated with the low could linger.
Given model differences in the track of the low, uncertainty
exists in the location of precipitation and precipitation amounts,
as well as temperatures and snow levels. If the ECMWF solution
were to pan out, it could mean a much cooler forecast with lower
snow levels. For now, have continued with a model blend until
details become more certain. Definitely something to watch though.
High temperatures across the plains on Sunday will start off in
the 60s to lower 70s for most locations, falling into the 50s and
potentially lower for most of the upcoming week. STP
&&
.AVIATION...
Mainly VFR conditions can be expected through today. A few areas
of showers will persist this morning east of Billings. Otherwise,
showers and isolated thunderstorms are possible once again this
afternoon and evening, mainly over the southwest mountains as
another weak disturbance moves over the area. STP/Hooley
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Sat Sun Mon Tue Wed Thu
-------------------------------------------------------
BIL 081 054/081 052/066 050/057 044/052 043/055 042/056
1/U 01/U 42/T 56/T 66/W 53/W 22/W
LVM 081 049/078 043/063 044/056 041/053 038/053 037/055
2/T 23/T 23/T 45/T 55/W 42/W 22/W
HDN 082 050/083 051/069 050/060 044/051 042/054 041/054
2/W 00/U 42/T 56/T 66/W 64/W 32/W
MLS 082 054/083 056/071 053/066 047/056 041/053 038/054
2/W 00/U 33/W 65/T 67/W 76/W 53/W
4BQ 081 053/083 053/070 052/070 046/053 040/052 038/055
2/W 00/U 22/W 55/T 66/W 65/W 53/W
BHK 077 049/078 051/070 051/069 048/057 041/051 037/051
2/T 00/U 23/T 56/T 66/W 66/W 63/W
SHR 080 048/082 051/068 049/063 044/050 039/051 038/054
1/B 10/U 23/T 45/T 66/W 54/W 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Duluth MN
908 AM CDT FRI SEP 30 2016
.UPDATE...
Issued at 908 AM CDT Fri Sep 30 2016
Updated the cloud cover forecast through tonight. It appears the
HRRR to be among the models best depicting the current low-level
stratus covering most of the Northland. The HRRR, and some other
models (such as the local WRF and 950 hpa RAP13 RH), are
indicating it will take longer to dissipate the stratus than the
previous forecast. Therefore, delayed its dissipation with the
latest update. Also, the HRRR, RAP, local WRF, and 4 km NAM
suggest the marine stratus, from the cool and humid easterly flow
from Lake Superior, will linger near the Twin Ports and Ashland
areas, so increased afternoon cloud cover for those areas. It then
looks like the marine stratus will surge back inland this evening,
so increased cloud cover into tonight, using the HRRR cloud cover
as a guide.
&&
.SHORT TERM...(Today through Saturday)
Issued at 344 AM CDT Fri Sep 30 2016
Stratus is continuing to be the major concern this morning. It is
developing over relatively warmer Lake Superior, where the average
surface water temperature is about 53 degrees, with the air
temperature now in the 40s where clouds have not formed. A lake
effect of sorts, with enough moisture and temperature differential
for clouds but not precipitation. The stratus downstream of Lake
Superior should continue early this morning, then gradually
dissipate late this morning as the airmass warms and mixing helps
get rid of it.
On the larger scale, the upper level low that we have been dealing
with for several days now is currently over the lower Ohio river
valley. This feature is expected to ease slowly north tonight and
Saturday, slowly pushing additional clouds and some chances for
precipitation into the southeastern portions of the forecast area
later tonight and Saturday. Otherwise, the ridge axis is expected
to linger over the northern portions of the area. Stratus may form
once again tonight, though the models are not picking up on it as
well as they did last night and have backed off on the cloud cover.
Higher clouds from the upper low may keep temperatures warm enough
to diminish the potential for stratus formation.
Temperatures today to be warmer than yesterday with the clouds
expected to clear, so have brought highs up into the mid-upper 60s
most locations. Tonight have kept things milder with lows in the
upper 40s south, and lower 40s north where there should be less
cloud cover. Saturday to be slightly cooler than today, depending
on exact cloud cover.
.LONG TERM...(Saturday night through Thursday)
Issued at 344 AM CDT Fri Sep 30 2016
The main focus on the extended initially will be a cutoff system
located in the central Great Lakes. The latest GFS/GEM/ECMWF
continues to be in excellent agreement for the weekend and early
next week bringing this feature northeastward into the eastern Great
Lakes/New England. Behind the cutoff, high pressure will nudge into
the Northland from north on Sunday. This will keep light winds out
of the east/northeast. Highs will be in the 60s throughout the
region.
The ridge axis will move east of the forecast area on Monday and
Tuesday, which will bring southerly warm air advection at 850 hPa
and result in a warming trend early in the week. Highs will be in
the mid to upper 60s on Monday and around 70 on Tuesday. As the
ridge departs, a trough will dig and deepen across the Western US
into the Plains. Ahead of the trough and area of low pressure will
develop in the Northern Plains and this feature will bring the
Northland the next chance of precipitation. This system will
gradually slide northeastward across the Northern Plains into
Ontario by late in the week. This will spread shower and
thunderstorm chances from southwest to northeast on Monday evening
through Wednesday. Removed thunderstorm mention for Thursday/Friday
as the system will be northeast of the CWA and instability will be
limited. Expect rain showers to linger around the backside of the
mature system. Still expect temperatures in the 60s on Wednesday,
but it will be cooler than Tuesday due to cloud cover.
Late in the week and heading into the weekend guidance continues to
show a cooling trend as northwest/westerly flow develops around the
back side of the system. This will bring near to below 0 degrees
Celsius 850 hPa temperatures for late on Thursday/Friday, which will
bring the coolest airmass of the Fall season to this point. Still
some run to run and model to model discrepancies with how cold of an
airmass will move in, with the latest ECMWF being the coldest and
farthest south at this point in time.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 704 AM CDT Fri Sep 30 2016
Will gradually see the IFR/LIFR stratus deck lift and scatter out
as the morning progresses per the latest NAM/RAP/HRRR guidance.
Expect VFR conditions at all terminals between 17Z to 20Z as the
stratus deck scatters out. Will see visibilities improve this
morning to VFR as fog lifts due to the mixed layer developing.
Guidance continues to hint at a stratus layer redeveloping late
tonight. Tried to account for this by hinting at IFR ceilings at
all terminals except for KDLH, where am fairly confident a stratus
deck will move in. Along with the stratus expect fog to develop
due to light winds.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 59 48 61 47 / 0 0 0 0
INL 63 45 64 45 / 0 0 0 0
BRD 67 48 67 47 / 0 0 0 0
HYR 64 48 64 46 / 0 0 0 0
ASX 58 51 59 49 / 10 0 0 10
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...Grochocinski
SHORT TERM...LE
LONG TERM...WL
AVIATION...WL
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1134 AM EDT FRI SEP 30 2016
.UPDATE...
Update for the potential for rainfall development through the
afternoon hours. Nearly all hires models advertise one or more
bands of showers to develop this afternoon through the evening
hours. Complex mid and upper level are keeping most of them from
zeroing in on any one corridor for the band/bands to set up making
it very difficult to adjust the going forecast right now. The
current water vapor images show this complex structure with
several trowel walls to possibly zero in on. Currently the radar
advertises 2 main bands to watch, one across the Saginaw Valley
and Thumb, with the other near the Ohio border. Current thinking
is that as the easterly 850mb jet peaks this afternoon and the
exit region of the cyclonic upper level jet max shifts closer to
SE MI, the mid level forcing will converge lower on the frontal
surface near the current Flood Watch is laid out. This will most
likely occur in the 18-00Z time frame. So no notable changes to
the forecast or Watch at this time. Additional chances for rain
overnight will be addressed at the 4pm issuance.
&&
.PREV DISCUSSION...
Issued at 646 AM EDT Fri SEP 30 2016
AVIATION...
Widespread IFR / borderline MVFR will persist through the day,
accompanied by gusty northeast wind and episodes of showers. Expect
general trend of IFR cig improving to MVFR with diurnal heating by
early afternoon with occasional returns to IFR within heavier
showers. Heaviest showers are expected south of KFNT mainly 19z-
23z...roughly in line with the latest HRRR and NAM runs. Just a low
chc of a thunderstorm not worthy of inclusion in the TAF attm.
For DTW...NE wind will be problematic through this evening and
potentially into late tonight. Wind is forecast to veer to a more SE
direction by Saturday morning. Episodic showers will continue
throughout this time.
//DTW Threshold Probabilities...
* High for cig aob 5kft.
* Low for tstorm impacting KDTW airspace mainly this evening.
PREV DISCUSSION...
Issued at 317 AM EDT Fri SEP 30 2016
DISCUSSION...
The regional radar show another round of showers advancing across
much of the forecast area this morning. Recent radar trends indicate
that the intensity and thus rainfall amounts through the morning
rush hour will be much less than what occurred yesterday. This next
round of rain is still associated with the quasi stationary upper
low centered over Kentucky. The water vapor loop indicates good
upper difluent flow across the upper Ohio Valley and eastern Great
Lakes. There is also strong transport of Atlantic moisture extending
from the Mid Atlantic region into the eastern Great Lakes. These
factors are supporting the extensive swath of showers from Se Mi all
the way to wrn Virginia.
During the course of the day, the center of the upper low is
forecast to only inch up toward the Indiana/Kentucky border. A
strengthening of the cyclonically curved upper jet max to the east
of the mid level circulation (across the Upper Ohio Valley) is
forecast to increase upper divergence across Se Mi. This will then
trigger an increase in mid level deformation across Srn Lower Mi.
Model cross sections do show a rather deep layer of weak elevated
convective instability with respect to a saturated air parcel. This
does suggest the potential for the development of a rather deep mid
level frontal circulation. The main forecast uncertainty at this
point is the location of the more persistent mid level frontal
forcing and thus heaviest rainfall today. The NAM and GFS continue
to suggest this mid level frontal circulation focusing the more
persistent rainfall from the northern Detroit suburbs up through the
I-69 corridor into southern Saginaw county this afternoon into the
evening. The HRRR and especially the ARW suggest the frontal
dynamics will become established a little farther south (Metro
Detroit/Ann Arbor south to the Ohio border). Given the compact
nature of the upper low, it certainly seems possible for any mid
level frontal forcing to set up farther south closer to the mid
level low center.
So it seems possible for locations (generally south of a Saginaw to
Bad Axe line) to pick up another half inch to inch of rain, with
a few locals receiving up to an additional two inches of rain.
For this reason and and with some uncertainty where any nearly
stationary bands of more moderate rain will set up later today, the
current flood watch will remain intact.
The upper low will inch its way northward across Indian tonight. The
upper level divergence and better mid level frontal dynamics will
slide to the west of the forecast area, while the feed of the
Atlantic moisture fractures. This will lead to decreasing chances
for showers during the night. While there is of course some slight
differences amoung the 00Z model suite in the exact track of the
upper low, they all suggest it will lift into srn Lower Mi on
Saturday, then slowly depart to the east of the region Sunday into
Monday. The associated cold pool aloft and resulting steep mid level
lapse rates will reside over the forecast area Sat into at least
early Sunday. This will support some redevelopment of showers and a
few thunderstorms. The potential for deep convection within close
proximity to the slow moving upper low could certainly support some
additional localized heavy rainfall Sat into Sun. Ample cloud cover
and showers will maintain a low diurnal spread in temps over the
next three days (highs in the 60s and lows in the 50s). The
departure of the upper low will bring drier and warmer conditions to
the region for the first half of next week.
MARINE...
Stalled low pressure system south of the Great Lakes will maintain
persistent fresh onshore flow into Saturday morning. This will
warrant continuation of existing Small Craft Advisories for all
nearshore zones due to both winds and elevated waves. Easterly winds
will diminish in intensity and back to the northeast by the end of
the weekend as the low begins to lift out of the area.
HYDROLOGY...
The pattern today will remain largely unchanged from yesterday.
Rounds of showers will continue to pivot around a stalled low
pressure system with additional rainfall totals of 2 inches possible
on a local basis, including in the Detroit Metro area. The heaviest
rain is forecast to fall between noon and 6pm today, mainly along
and south of the I-69 corridor. Urban and small stream flooding will
once again be possible along with minor flooding on area rivers.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Flood Watch until 8 PM EDT this evening FOR MIZ060>063-068>070-075-
076.
Lake Huron...Small Craft Advisory until midnight EDT tonight FOR LHZ422.
Small Craft Advisory until 5 AM EDT Saturday FOR LHZ421-441>443.
Lake St Clair...Small Craft Advisory until midnight EDT tonight FOR LCZ460.
Michigan waters of Lake Erie...Small Craft Advisory until midnight EDT tonight FOR LEZ444.
&&
$$
UPDATE.......DRK
AVIATION.....JVC
DISCUSSION...SC
MARINE.......JVC
HYDROLOGY....JVC
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Lincoln IL
1002 AM CDT FRI SEP 30 2016
.UPDATE...
Issued at 1002 AM CDT Fri Sep 30 2016
Upper low continues to spin near Louisville this morning, with
periodic showers pushing westward into Illinois. No real change
expected in this pattern expected through this evening, before the
low finally starts to move northward after midnight. Main updates
to the forecast generally involved massaging the PoP trends into
Saturday, with little change needed to temperatures.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 308 AM CDT Fri Sep 30 2016
07z/2am water vapor imagery shows center of persistent upper low
centered over central Kentucky. Scattered showers continue to pivot
around the low, with the most concentrated area of rain immediately
to the north of the center over southern Indiana/far northern
Kentucky. Based on recent radar loops, have opted to go with likely
PoPs along/south of a Paris to Effingham line early this
morning...with rain chances steadily decreasing further west toward
the Illinois River Valley. As the day progresses, additional
showers will develop further west, resulting in increasing PoPs
across the remainder of the KILX CWA. With upper low slowly lifting
back northward and lapse rates steepening, MUCAPE values are progged
to reach the 600-1000J/kg range across the east later today. As
a result, have mentioned isolated thunder along/east of I-55 this
afternoon. Given extensive cloud cover and scattered showers,
high temperatures will once again remain in the middle to upper
60s. Showery weather will continue tonight, although areal
coverage will decrease due to loss of daytime instability. Will
carry chance PoPs everywhere, with lows dropping into the middle
50s.
.LONG TERM...(Saturday through Thursday)
ISSUED AT 308 AM CDT Fri Sep 30 2016
Upper low will continue to lift northward into northern Indiana by
Saturday evening. With this feature still in the vicinity, am
expecting scattered showers and cool conditions to persist through
Saturday. After that, all model solutions track the low into the
Great Lakes by Sunday, resulting in rising heights across the
Midwest and a return to warmer/drier conditions for early next week.
With increasing amounts of sunshine, high temperatures will reach
the lower 70s on Sunday, then the middle 70s by Monday.
The next big weather question will revolve around how quickly a
western CONUS trough can translate eastward next week. The speed of
this system will likely be impacted by Hurricane Matthew as it
tracks northward off the North Carolina coast by the middle of next
week. Given the expected track/intensity of Matthew, think a slower
eastward progression of the trough is prudent. As a result, have
maintained dry conditions through Tuesday night, with only low
chance PoPs arriving across the western CWA by Wednesday. Wednesday
night into Thursday appears to be the primary time frame for precip
chances as the trough and its associated cold front gradually make
their way eastward into Illinois. Before the precip arrives
however, a couple of very warm days with temperatures well into the
70s and perhaps to around 80 degrees will be on tap for Tuesday and
Wednesday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 654 AM CDT Fri Sep 30 2016
An occluded low pressure system churning to the SE of our
forecast area will keep clouds and periodic showers in the TAFs
over the next 24 hours. IFR clouds will dominate the first few
hours of the 12z TAFs, with LIFR at BMI. Daytime heating will lift
the LCL, so that MVFR conditions prevail for the rest of the day.
There may be enough mixing to break a few holes in the clouds this
afternoon, but expect overcast conditions for the most part. IFR
clouds and MVFR visibility in fog will likely develop tonight as
the low pressure center lifts north into Indiana.
Rain chances will be hard to pinpoint, but the latest HRRR and
RAP models point toward a band of steadier rains arriving from the
east later this afternoon into the evening. Have focused that time
frame for prevailing rain for CMI and DEC. Outside of that, have
kept VCSH at the other terminals.
Surface winds will remain out of the north-northeast over the next
24 hours, with wind speeds increasing to 10 to 15 kts today. Look
for an occasional gust up to 20 kts at times, especially during
any showers that affect the TAF sites.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Melbourne FL
935 AM EDT FRI SEP 30 2016
.UPDATE...
Today...Weak frontal boundary extending from northeast Florida
through the Big Bend region into the Gulf of Mexico will only move a
little to the east today, so the real dry air behind it won`t reach
east central Florida. The highest precipitable water values will be
in the south though as some drier air aloft has filtered in over the
north.
The morning sounding at Tampa showed precipitable water 1.72 inches
with still cool temps aloft (500mb -8C). Southwest steering flow
was still around 15 knots but should decrease slightly through the
day. The GFS shows decent divergence aloft during the afternoon
with 500 mb temps cooling a degree or so.
The weakening frontal trough approaching will cause surface winds to
diminish so a sea breeze will develop and provide added lift over
the east side of the peninsula.
West coast sea breeze storms will push steadily inland this
afternoon, though probably not quite as fast as yesterday.
Additionally, there was a weak pre frontal convergence line from
north of Tampa to Lake George early this morning that may provide
additional focus for storms as they increase in coverage/intensity
while traversing the peninsula. The HRRR model has been showing an
increase in lightning and wind gusts near the east coast as
convection and boundaries moving across the peninsula interact with
the east coast sea breeze.
So several ingredients are coming into place for an active
afternoon. We have already outlined the potential for strong storms
in the Hazardous Weather Outlook along with a slight chance for a
severe storm or two. Little change to the previous products are
needed.
&&
.AVIATION...
Scattered storms will again spread west to east across the peninsula
again while increasing in coverage/intensity. Timing looks a little
later than yesterday. A few of the storms will again produce strong
wind gusts over 35 knots and frequent lighting strikes. The east
coast sea breeze will likely result in the strongest storms being at
the coastal terminals during the late afternoon and early evening.
&&
.MARINE...
Today...The pressure gradient will ease today as a weakening frontal
boundary moves very slowly eastward from northeast Florida and the
Big Bend region. This will cause southwest winds to diminish below
10 knots and a sea breeze will form this afternoon. Seas should be
less than 3 feet.
However, boaters will need to be alert for strong storms moving off
the coast by late afternoon. Expect Special Marine Warnings again.
&&
.MLB Watches/Warnings/Advisories...
FL...None.
AM...None.
&&
$$
FORECASTS...Lascody
IMPACT WX/AVIATION...Sedlock
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
513 AM CDT FRI SEP 30 2016
.SHORT TERM...(Today and tonight)
Issued at 332 AM CDT Fri Sep 30 2016
Cut-off H5 low that drifted down into KY yesterday is already
starting to lift back to the NNW this morning. Biggest implication
for us is that the low stratus looks to return from the east faster
than initially indicated, with sky grids increased considerably this
afternoon in western WI/eastern MN and overnight for western MN. 925-
850 RH off the GFS/NAM/RAP shows cloud cover currently over SE WI
ending up in eastern SD by Saturday morning. Of interest though is
that the NAM in particular shows a wedge of dry air dropping down
from Lake Superior tonight, with skies actually clearing out some in
western WI tonight as the stratus is heading for SD. Given the
expected cloud cover, low 70s are unlikely again today out in
western WI.
Other issue more for this morning is a batch of low stratus coming
down off of Lake Superior. The HRRR shows this cloud cover getting
down to about the Twin Cities/Wilmar in the for of fog/low stratus.
Though this may result for a cloudy morning for much of central MN,
this looks to mix out by mid-late morning with a brief window of
sunny skies in the afternoon before cloud cover arrives from the
east.
Last change made in the short term was to keep the Eau Claire area
dry through 12z Saturday. CAMs and deterministic models alike keep
the MPX area dry, with any rainfall Friday night confined to eastern
WI where moisture on the 290-305k isentropic surfaces.
.LONG TERM...(Saturday through Thursday)
Issued at 332 AM CDT Fri Sep 30 2016
The period begins with a stubborn upper level low lifting slowly
northward across Indiana. Considerable cloudiness will occur
across the FA in the morning along with a few showers from the
southeast corner of MN through KEAU. The cloudiness should begin
to breakdown from the northeast in the afternoon as drier air
spreads in along with the upper level low beginning to drift east.
This leaves a horseshoe of higher cloud cover curving from
western MN through IA to eastern WI. The cloudiness will breakdown
Saturday night leaving us with a fine early fall day on Sunday.
High temperatures this weekend will be very close to seasonal
values with lows about 5 degrees above normal.
We have had a little bit of a roll reversal for next week between
the EC and GFS with regards to the weather system impacting the
FA in the Tuesday through Thursday period. The EC continues to
inch forward a bit on the leading edge of the rain on Tuesday
while the GFS is looking more like earlier runs of the EC on
keeping rain out of the Twin Cities until Wednesday afternoon. The
Canadian would also keep rain out of the local area until
Wednesday afternoon.
One of the differences noted is that the EC has more of a
positively tilted upper wave while the GFS and Canadian are more
negatively tilted. At this point, we allowed small pops into
western MN on Tuesday with the small pops working across eastern
MN and western WI Tuesday night. This will be too fast if the
latter solutions are correct. Another item noted is the strength
of the low level moisture transport Tuesday night and early
Wednesday across western MN. This area will likely see the most
rain from this event with amounts of a half inch to one inch
likely. The long term closes out with a cold front pushing east of
the FA with a breezy southwest wind occurring on Thursday.
High temperatures early next week will continue to be close to
seasonal normals. However, highs will trend downward thereafter,
with readings only in the middle 50s to lower 60s expected on
Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 507 AM CDT Fri Sep 30 2016
Fog/low stratus has slowly built southwest from Lake
Superior through the night. Only MPX terminal that will
definitely be in it is STC, with AXN on the western edge of the
clouds and MSP/RNH/EAU near its southern edge. Followed the idea
of the HRRR that this fog will slowly mix out through the
morning, finally clearing out of central MN in the mid to late
morning, which is a bit slower than what LAMP guidance has. Of
course is this is going on, stratus has been rapidly pushing west
across WI through the night and will be moving from west to east
across the area today. Not expecting fog to be as much of an
issue tonight as forecast soundings show us going the route of a
2k-5k foot CIG.
KMSP...Fog/stratus has made it into the north metro and
northeast winds will continue to try an push it toward MSP. At
this point, not very confident of the stratus will reach MSP this
morning, so maintained a tempo group. Confidence is high that
status coming in late this afternoon will remain above 018.
/OUTLOOK FOR KMSP/
Sat...VFR. Wind ENE at 5 kts.
Sun...VFR. Wind NE at 5 kts.
Mon...VFR. Wind SE at 5-10 kts
&&
.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...RAH
AVIATION...MPG
Area Forecast Discussion
National Weather Service Blacksburg VA
726 AM EDT Fri Sep 30 2016
.SYNOPSIS...
A strong upper level area of low pressure will remain just west of
the mountains today before slowly lifting to the north later
tonight into Saturday. This system will combine with a residual
stationary front across the region to produce periods of showers
and thunderstorms into late tonight. The low will move northeast,
away from the region, resulting in drier weather this weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 245 AM EDT Friday...
Broken bands of heavy rain producing showers continue across the
west under the tail of a passing speed max and over the northeast
third with added low level convergence early this morning. Expect
this trend to persist through daybreak with main coverage likely
shifting into the northwest sections as multiple short band type
features merge. Then questions with added coverage through the day
as the upper low begins to shift back north while the jet aloft
remains strong over continued low level convergence espcly north
and east this afternoon. Will also have to watch for another band
to work north along the southern Blue Ridge this morning as
several solutions including the latest HRRR and 00z ECMWF paint
quite a bit of QPF extending north from the North Carolina
foothills into the west between 12-16z. This along a residual
convergence axis well to the south and eventually along the
eastward moving occluded front that will swing across the Blue
Ridge this afternoon. This along with some breaks and decent
instability southeast may allow one final heavier band of
shra/tsra to evolve across the north/east this afternoon given
strong veering with height and moist PWATS. However with
uncertainty wont hoist another watch at this point while allowing
the ongoing FFA to end with this package given only current
scattered nature to shra attm.
Otherwise again running with likely/cat pops today, except tapering
to chance heading into the southwest zones where will likely
remain in the dry slot aloft with limited added showers. Lowered
high temps a little under easterly flow and more clouds as
expecting a range from near 80 southeast to only the 60s far west.
Upper low should continue to trudge north toward the Ohio Valley
overnight allowing drier air aloft to gradually win out from
southwest to northeast behind the passing surface occluded
boundary. Think still decent coverage in the north/east during the
evening before showers fade late tonight with little focus
remaining. May even see some clearing work in from the southwest
after midnight so mostly chance pops tapering to spotty showers
northeast sections by dawn. Expect more clearing west to allow
temps to fall into the cool 40s in spots with overall low/mid 50s
elsewhere, except low 60s far east.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 305 AM EDT Friday...
Drying trend will continue over the weekend as the upper low
finally lifts farther north and weak high pressure slides in from
the west. May still have an isolated shower around early Saturday
over the north, otherwise cutting pops with more sunshine on tap
by the afternoon. Another spoke of energy looks to rotate around
the upper low Saturday night with this feature reaching the
western mountains later Sunday. Moisture quite limited with the
weak associated front but cant totally rule out an isolated shower
western slopes late Sunday into Sunday night. Otherwise expecting
mainly clear skies Saturday night and mainly sunny Sunday before
clouds invade the west late. High temps to remain mild under
west/southwest flow aloft with mostly 70s both Saturday and Sunday
and lows mostly 50s Saturday night given good radiational cooling
conditions.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 330 PM EDT Thursday...
The upper low will give way to ridging in the eastern US through the
early part of next week. This stall the approaching front and allow a
large area of high pressure to settle over New England and wedge down
the east side of the Appalachians. The big variable lies with the
potential track of TS Matthew as it is expected to turn north and move
up the Atlantic coast. The exact track of Matthew will determine how
much, if any, precipitation it can push into the region from the east
and how much overrunning precipitation will develop as it interacts
with the wedge. Right now, the most likely scenario is for some light
overrunning precipitation to develop by Tuesday and increase a bit into
Wednesday especially in the east, with any significant effects form
Matthew remaining to our east.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
As of 711 AM EDT Friday...
Variable but overall sub-VFR conditions will prevail this morning with
cigs fluctuating between MVFR and low end IFR at times. Best
coverage of showers/storms resulting in vsby restrictions look to
occur along the KBCB-KROA corridor this morning with weaker bands
elsewhere espcly around KLWB. Thus will include either a vicinity
or tempo mention with perhaps a brief prevailing group of lower
cigs/vsbys at these locations.
Uncertainty continues with the degree of added convective coverage
today with the upper low starting to retrograde while the
occluded boundary to the west shifts east and starts to cutoff
deeper moisture late. Models continue to focus showers and storms
across the northwest corridor through midday, then along and
north of a KLWB- KDAN line. Should see any IFR conditions slowly
improve to MVFR/VFR by midday/early afternoon though think places
like KROA/KLYH/KLWB will keep MVFR to the end of this taf period.
Will include more showers and storms given decent probability
during the afternoon in most locations with tapering of showers by
the evening as the main corridor of deeper lift slides north.
Extended aviation discussion...
A deep upper low will finally shift farther to the north by
Saturday and away from the region on Sunday. This should allow for
a gradual improvement in cigs after early sub-VFR Saturday with
widespread VFR Sunday as weak high pressure builds in. Looks like
overall VFR to then prevail into early next week outside of some
upslope low clouds Monday and perhaps along the Blue Ridge Tuesday
as another weak wedge develops under high pressure to the north.
&&
.HYDROLOGY...
As of 330 AM EDT Friday...
Overall convective bands have decreased in both coverage and
intensity across the north early this morning so letting the
watch go for now. Otherwise main concern again with the
redevelopment of heavier bands from the south/southeast through
the day as multiple areas of convergence pivot around the upper
low to the west. Likely looking at another inch or so of rainfall
on average across the north with locally higher amounts where
deeper convection mixes in. Also some concern along the Blue Ridge
through midday with possible very early morning redevelopment and
training as seen a few models. Given now saturated soil conditions
and elevated stream/creek levels will be easier for flooding or
flash flooding to develop while still appears most mainstem rivers
will stay below flood levels for now.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM...MBS
AVIATION...AMS/JH/WP
HYDROLOGY...WP
Area Forecast Discussion
National Weather Service Denver/Boulder CO
322 PM MDT Fri Sep 30 2016
.SHORT TERM...(Today and tonight)
Issued at 322pm MDT Fri Sep 30 2016
Today and tomorrow a weak upper trough will be slowly moving east
through the weak upper ridge over Colorado. The airmass over
Colorado is quite moist (GJT was over 200 percent of average this
morning) and there were numerous cloud levels over the mountains.
There is some clearing seen in the higher clouds over Colorado...
and we just now seeing lightning over the western mountains. At
the surface a low pressure center resides over southeast
Colorado...and an apparent front went through metro Denver this
morning and is seen moving through the Pueblo radar at 20z.
The boundary and the clouds resulted in slightly cooler
temperatures today.
New HRRR continues the idea of precipitation shifting to the
southeast this evening. That is reflected in the forecast so
no changes...scattered pops over the palmer divide this
evening...then showers diminishing across the cwa by midnight.
Tuesday will be similar...as the moisture will continue to reside
over the mountains and the southwest flow will continue. There
will be scattered showers and thunderstorms over mountains...with
a much lower chance over the plains. temperatures will be only a
degree or two higher than today.
LONG TERM...(Saturday through Thursday) Issued at
322 PM MDT Fri Sep 30 2016
Saturday night the upper level trough will be centered over the
Rocky Mountain Region...with a deep upper level low pressure trough
just off the west coast of the United States. On Sunday...the upper
ridge will shift eastward over the Central Plains as the upper level
storm system deepens over northern California. This pattern should
result in dry and warm weather across north central and northeastern
Colorado through the weekend...with only isolated showers and storms
in the mountains. On Monday...the upper trough deepens over the
Great Basin...with a moderate to strong southwesterly flow aloft
over Colorado. Models are showing a 100kt+ KT jet over western
Colorado by Monday Afternoon. Some orographics and lift from the
upper jet should produce scattered afternoon and evening showers and
storms over the high country...with dry and warm weather east of the
mountains.
On Tuesday...the center of the upper low tracks north of Colorado.
The GFS has it moving over Wyoming and the Dakotas...while the ECMWF
moves it over Montana. The combination of the frontal passage and
cold air advection from the upper trough will bring an end to the
unseasonably warm temperature across the region. Temperatures on
Tuesday should be 15 to 20 degrees colder than Monday`s readings.
Cold advection behind the front...combined with the gradient between
the upper high over the northern Rockies and higher pressure over
Colorado should produce gusty winds over the foothills and portions
of northeastern Colorado from early Tuesday morning through Tuesday
afternoon. The Sangster Model suggests the potential for strong
winds across the foothills. In addition...the northern mountains
should see a good chance for snow due to cold air advection and
orographic westerly flow.
Wednesday should be the coolest day of the week on the plains due to
increasing cloudiness and less downslope flow. We should still see
scattered snow showers in the mountains due to a continued westerly
orographic flow. The models also show an upper level disturbance
moving across the region...which could produce isolated showers
across the plains.
Warmer and drier weather is expected by Friday as upper level high
pressure rebuilds over the Rocky Mountain Region.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 224 AM MDT Fri Sep 30 2016
showers continue to move north of the metro area...we still think
there will be a transition to showers and possibly thunderstorms
developing over and near the palmer divide this evening. Metro
area airports will be VFR...but there could be spotty mvfr
ceilings near showers. With a surface low in southeast Colorado
the surface winds will remain northerly today...and most likely a
westerly drainage wind tonight.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...RTG
LONG TERM...Kalina
AVIATION...RTG
Area Forecast Discussion
National Weather Service Duluth MN
306 PM CDT FRI SEP 30 2016
.SHORT TERM...(This evening through Saturday)
Issued at 306 PM CDT Fri Sep 30 2016
Summary: Persistent easterly flow from Lake Superior will
maintain a similar weather pattern into Saturday. Marine stratus
will surge back inland this evening and overnight, only to linger
again Saturday morning before dissipating for inland areas
Saturday afternoon, but remaining over the Lake. Low temperatures
will again fall into the 40s tonight, and lower to middle 60s are
expected Saturday afternoon.
A large, vertically-stacked area of low pressure over Kentucky
will wobble its way north to Indiana/Ohio by Saturday, while a
ridge of surface high pressure will continue to extend from Quebec
through northern Ontario into Minnesota. This pattern will
maintain light easterly flow across the Northland, which will be
relatively humid because of the moisture contribution from Lake
Superior.
The Northland saw stratus from Lake Superior spread to most of
the Northland last night and early this morning, only to linger
well into the day. The Lake is fairly warm, with a surface
temperature in the low 50s, while temperatures inland fell into
the 40s last night. The relatively warm and humid air from the
lake easily clouded over as it ran over the cool air inland. The
stratus gradually dissipated through today to result in most areas
clearing, but it remained over Lake Superior and slightly inland
downwind of the Lake, such as near the shores of the Twin Ports
and Ashland. The overall weather pattern will not be changing to
any significant degree into tomorrow, so it looks like the
Northland is stuck in repeat mode. The HRRR has been handling the
stratus the best amongst the models, and it has the marine stratus
surging back inland this evening and overnight. Increased the
cloud cover forecast for tonight and tomorrow with a heavy
influence from the latest HRRR runs. Other models support/suggest
the marine stratus moving back inland tonight for most areas, too,
such as the 950 hpa RAP RH and the local WRF.
The Northland saw visibilities come down overnight due to the
stratus, but there were few observations meeting true fog (less
than 1 mile). Tonight will likely be similar. However, there could
be some spots with foggier conditions wherever the stratus is low
enough, such as in higher terrain, so have patchy fog moving
inland tonight.
The model soundings are indicating a brief period of deepening
stratus from near the Twin Ports into the Arrowhead, near and
shortly after dawn tomorrow. The GFS even has a little
precipitation. Added patchy drizzle for this area because it looks
like the stratus layer might be deep enough to squeeze out a
little moisture.
Bands of cloud cover from the upper-level low will swing west
into the southeast forecast area late today into early Saturday,
and it might produce some very light rain for the far southeast
forecast area, near Prentice and Ogema.
.LONG TERM...(Saturday night through Friday)
Issued at 306 PM CDT Fri Sep 30 2016
The forecast area will remain positioned between low pressure
rotating to our south near Chicago, and high pressure anchored
to the north over Ontario into next week. The flow will turn
southerly and strengthen through the beginning of next week as the
next low pressure system advances into the Dakotas.
Latest runs of the GFS/ECM are in surprisingly good agreement with
the low that will impact the region next week considering its
out on day 5 and beyond. The long wave trough, with closed 500hPa
low, is projected make landfall on the western coast Sunday, then
migrate east across the central US and into the Northern Plains by
Wednesday. This track will allow for a warm front to lift over the
region early in the week, bringing a surge of warm gulf air along
with a chance for showers and thunderstorms with it. Once the low
passes over the western Lake Superior region and cold air
advection makes a return for the upcoming weekend, a much cooler
airmass with 850hPa temps well below zero will dive into the
Northland. This may be our first shot at light snow accumulations
along the borderland.
However, suspect overall timing of the long wave trough and
associated stacked low/precipitation chances will be slower than
currently in forecast. This is due to model bias of typically
progressing closed systems too fast, as well as the impact of the
tropical storm approaching the east coast during this time; which
the GFS and ECM are showing large differences with.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1249 PM CDT Fri Sep 30 2016
The fog and LIFR ceilings slowly eroded through the morning, with
only KINL still being impacted into this afternoon. Elsewhere
vfr conditions with mostly sunny skies will prevail for remainder
of the day. Expect low clouds and areas of fog to redevelop
overnight. Wrap around mid level clouds, associated with an area
of low pressure to our south, will also lift into the forecast
area overnight and linger into Saturday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 49 61 46 63 / 0 10 0 0
INL 44 66 47 69 / 0 0 0 0
BRD 48 65 46 69 / 0 0 0 0
HYR 49 66 45 66 / 0 0 0 0
ASX 49 61 47 64 / 0 0 0 0
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...Grochocinski
LONG TERM...Graning
AVIATION...Graning
Area Forecast Discussion
National Weather Service Wichita KS
310 PM CDT FRI SEP 30 2016
.SHORT TERM...(This evening through Monday night)
Issued at 310 PM CDT Fri Sep 30 2016
Forecast highlights: Fairly quiet weather through Monday, with
shower/thunderstorm chances increasing Monday night- Wednesday
night. Quiet weather again by late week and next weekend.
Could see fog development later tonight into early Saturday
morning over portions of east-central and southeast Kansas, due to
light winds and clear skies atop surface ridge axis. RAP soundings
indicate potential for dense fog amidst a moistening boundary
layer, so evening shift will need to monitor.
Cannot rule out a few showers/thunderstorms west of I-135 Saturday
night into Sunday morning given increasing 850-700 warm advection
and moisture transport. Forcing and elevated instability are weak,
so not expecting widespread activity.
Otherwise, daytime temperatures will steadily warm through Monday
as southerly flow and atmospheric thickness gradually increase
ahead of a deepening western CONUS trough. Readings by Monday
should reach the 80s most areas, with stout/gusty south winds as
lee trough strengthens over the High Plains. Expecting
shower/thunderstorm chances to increase generally west of I-135
Monday night, as large scale ascent from deep western CONUS trough
and associated cold front approach from the west.
.LONG TERM...(Tuesday through Friday)
Issued at 310 PM CDT Fri Sep 30 2016
Per medium range model consensus, shower/thunderstorm chances
continue areawide Tuesday- Wednesday night, as the western CONUS
longwave trough and associated cold front moves across Mid-
America. Quite a bit of model spread regarding the evolution,
magnitude, timing and placement of various synoptic features, so
confidence on forecast specifics remains low. Despite moderate to
strong forcing and decent deep layer shear, thinking overall
threat for severe weather is on the low side throughout this event
given limited moisture return and associated poor instability.
Cooler and pleasant weather will return by late week in wake of
the cold front, with upper ridging building from the west.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1220 PM CDT Fri Sep 30 2016
VFR Weather is expected to persist during the TAF forecast valid
period. Light/variable winds are forecast with a surface ridge
continuing to stretch from Minnesota/Iowa to Eastern Kansas. Some
High-level cloudiness will continue to spread over central Kansas
from the west through Saturday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 51 76 56 79 / 0 0 10 10
Hutchinson 50 76 54 78 / 0 0 10 10
Newton 50 74 54 77 / 0 0 10 10
ElDorado 51 75 54 78 / 0 0 10 10
Winfield-KWLD 51 77 55 80 / 0 0 10 10
Russell 49 76 53 79 / 0 10 20 20
Great Bend 50 77 53 79 / 0 10 20 20
Salina 49 76 54 79 / 0 0 10 10
McPherson 50 75 54 78 / 0 0 10 10
Coffeyville 50 77 53 80 / 0 0 0 0
Chanute 50 75 52 78 / 0 0 0 0
Iola 50 74 52 77 / 0 0 0 0
Parsons-KPPF 50 76 51 79 / 0 0 0 0
&&
.ICT Watches/Warnings/Advisories...None.
&&
$$
SHORT TERM...ADK
LONG TERM...ADK
AVIATION...JMC
Area Forecast Discussion
National Weather Service Indianapolis IN
705 PM EDT Fri Sep 30 2016
.UPDATE...
The Aviation section has been updated below.
&&
.SYNOPSIS...
Issued at 245 PM EDT Fri Sep 30 2016
A strong upper low near Louisville will lift north across Indiana
tonight and Saturday before moving into the eastern great lakes
Sunday. This will result in more cool and showery weather through
Sunday. Thunderstorms will also be possible early evening and
Saturday and Saturday evening.
High pressure will bring a return to dry weather to the area
starting Sunday, and temperatures will warm to the 70s next week.
Finally, shower chances will return by Wednesday night as a frontal
system moves through from the west.
&&
.NEAR TERM /Remainder of the afternoon and tonight/...
Issued at 245 PM EDT Fri Sep 30 2016
Severe potential and pops are the main concerns through tonight as
an upper low sends several lobes of vorticity across central
Indiana.
Models handle upper low slightly different regarding positioning,
but all solutions and HRRR favor carrying good chance to likely pops
through early evening with the best chances across the northeast as
arcing band continues to spiral northeast across that area. After
that, model time sections show some mid level drying which, along
with loss of solar heating, favors lower pops after dark with chance
looking good most areas.
Models have a marginal risk of severe across areas our northeastern
counties with the southwest border over northeastern Boone county,
the northern border adjacent to IWX counties and the eastern border
adjacent with ILN counties. With upper and surface lows around along
with an occluded front, would not rule out brief isolated tornadoes
along with and maginally large hail per SPC Day1 Outlook. The threat
should be over by 8 pm as mentioned in the Hazardous Weather Outlook
and Weather Story.
Status and or fog will be an issue once again tonight per the SREF
and GFS LAMP. For now, went with patchy fog. Wording may need to be
stepped up for the evening update.
Favor lows on the warmer side of MOS with clouds hanging around.
&&
.SHORT TERM /Saturday and Saturday night/...
Issued at 245 PM EDT Fri Sep 30 2016
Main challenge to the short term will be pops.
Models have some difference, but a non-Canadian blend takes the
upper low over northern Indiana on Saturday and into southeastern
lower Michigan Saturday night. This blend is favored due to better
clustering with the ensembles. This suggests high pops once again on
Saturday and lower pops Saturday night with loss of heating and low
pulling away. Will continue to keep thunder in for the daytime and
early evening as has been the trend and par for the course for early
fall systems. The GFS and NAM had most unstable CAPEs to 1000 j/kg
at 18z Saturday and dropping off at 00z Sunday.
Will stick with afternoon highs on the lower side and overnight lows
on the warmer side of MOS due to extensive cloud cover.
&&
LONG TERM /Sunday through Friday/...
Issued at 238 PM EDT Fri Sep 30 2016
Sunday will be a transitional day as the upper low over the
eastern great lakes begins to move away from our region and
high pressure builds in from the plains. Models indicate
there could be a slight chance of showers most areas Sunday
with the possible exception of the far west.
Sunday night through Wednesday will be dry with a high
pressure ridge across our region. A cold front which will
be across the plains Wednesday will move to the Mississippi
river Thursday morning and across Indiana Thursday night.
The latest GFS...Canadian and European models indicate a
few showers may reach western Indiana late Wednesday night
and then scattered showers and a few thunderstorms Thursday
and early Thursday night. This front may bring a few showers
to eastern sections early Friday with dry and cooler weather
after that.
Concerning temperatures...models have trended a little cooler Sunday
with highs in the upper 60s to lower 70s. Highs will be mostly in
the 70s Monday through Thursday...but with some areas reaching
the lower 80s Wednesday. Then highs Friday will be in the upper
60s to lower 70s. Lows will be in the lower 50s Monday morning
warming to near 60 Wednesday and then cooling some days 6 and 7.
Raised high tempertures slightly Monday through Wednesday with
lots of sun and warm advection. Otherwise...stayed close to
Super Blend temperatures most other periods.
&&
.AVIATION /Discussion for the 01/00Z TAFs/...
Issued at 705 PM EDT Fri Sep 30 2016
VFR conditions will again deteriorate to MVFR or worse overnight.
Upper low continues to spin over the region, bringing showers,
isolated thunder, and widespread cloud cover. Expect ceilings to
deteriorate again tonight, with fluctuations likely.
Winds will be less than 10kt through the period, variable at times.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM...JH
AVIATION...NIELD
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
340 PM EDT Fri Sep 30 2016
.SHORT TERM...(This evening through Saturday night)
Issued at 340 PM EDT FRI SEP 30 2016
18z sfc analysis shows a broad area of low pressure through the
Ohio Valley and Southern Appalachians. Most of East Kentucky is in
the southwest quadrant of this system and pretty much dry slotted
keeping the showers and any storms west and northeast of the CWA.
Plenty of clouds and morning fog slowed the temperature rise
through eastern Kentucky today, but with more clear breaks the
sunshine is helping to send temperatures into the low and mid 60s.
Meanwhile, dewpoints are running in the low 50s for most places
with the winds light and variable.
The models are in good agreement aloft with their handling of the
fairly deep closed low wobbling over the Ohio Valley through the
weekend. They all have the low tracking slowly due north with some
minor divergence in solutions late in the short term. The GFS
moves the low to the Great Lakes a notch quicker than the others,
but strength is similar from all models. They all, also, have
ample mid level energy rotating through the low over head. Given
the agreement will favor a blended solution with the HRRR and
NAM12 leaned toward in the near term.
Sensible weather will feature another cool evening and overnight
as the clouds partially break up. This will make for varying
amounts of radiational cooling and better radiational fog
formation at times overnight. The latest CONSShort guidance keeps
the more extensive and thickest fog just to the west of the CWA
tonight. For this reason, will allow some mainly valley fog in
the grids toward midnight and through dawn with some locally dense
patches in the deeper valleys toward 12z. The next pinwheel of
energy aloft may bring some light showers to western parts of the
CWA overnight and into Saturday morning, but most of the area
should remain dry. Look for the fog to burn off Saturday morning
and a bit more sunshine should allow for temps to reach the upper
60s to low 70s most places. Similar conditions are anticipated
Saturday night with more valley centric patchy fog late. Also,
a couple stray showers may move in late Saturday into Sunday
morning as the upper low and sfc low start to move out.
Again used the CONSShort and ShortBlend as a starting point for
most grids into Saturday morning with the SuperBlend used
thereafter. Made only minor changes to the T grids based on our
terrain with the clouds around. As for PoPs - ended up on the low
side of a MOS blend through Sunday morning.
.LONG TERM...(Sunday through Friday)
Issued at 248 PM EDT FRI SEP 30 2016
The forecast for the extended should feature isolated rain showers
moving across eastern Kentucky, as an area of low pressure aloft
moves across the lower Ohio Valley region on Sunday, a period of dry
and pleasant weather, and possibly another round of rain Thursday
night into early Friday. A cold front would be the trigger for any
rain we may see toward the end of next week. Temperatures during the
period are expected to max out in the 70s each afternoon, and bottom
out in the 50s each night. A few spots may reach or slightly exceed
80 degrees Tuesday through Thursday, mainly along and south of the
Hal Rogers Parkway and Highway 80 corridor.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 210 PM EDT FRI SEP 30 2016
The lower cigs and last of the fog are clearing out of the TAF
sites ATTM. Expect most locations will go VFR for a time into the
early evening hours. However, we will see a round of shower
activity move toward eastern Kentucky from the west this evening
into tonight, but too much uncertainty remains in timing/spatial
extent of this activity to warrant mention for the TAFs at this
time. Cloud cover will remain variable through the forecast period
with some lowering of cigs anticipated overnight, but still
plenty of questions concerning the timing and occurrences of sub-
VFR conditions. Fog, locally dense, looks to be a good bet in
valleys tonight, but TAF sites will likely be limited to mainly
MVFR vis restrictions, at worst, through 13z Saturday. Following
this, anticipate improving conditions into Saturday afternoon with
mostly VFR cig and vis values. Winds will remain light and
variable through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
Area Forecast Discussion
National Weather Service Marquette MI
417 PM EDT Fri Sep 30 2016
.SHORT TERM...(This evening through Saturday)
Issued at 416 PM EDT FRI SEP 30 2016
WV imagery and RAP analysis indicated a mid/upper level low over far
srn Indiana and a ridge from the srn plains to the upper MS valley
and nrn Great Lakes. Radars indicated rain over much of the srn half
of lower MI associated with 700-300 mb qvector conv and 305-310k
isentropic lift to the north of the low. Some light showers or
sprinkles were also approaching MNM but had largely dissipated as
they moved into drier air and away from the stronger forcing.
Otherwise, mid clouds were gradually spreading into the srn cwa.
Diurnal stratocu had also developed over the cntrl cwa.
Tonight, expect light showers to continue to spread gradually to the
northeast with the potential for sct/isold -shra/sprinkles over the
srn cwa. With only weak forcing and a dry layer below 750 mb,
confidence is low with how far north any measurable pcpn will
develop. Increasing clouds will keep temps from falling off as much
with min readings from the upper 40s to mid 50s, coldest inland
west. Even though there is still enough low level moisture,
afternoon dewpoints in the mid 50s, to support patchy fog
development the clouds will reduce fog potential over the south and
east.
Saturday, with the mid level low drifting northward to far ne
Indiana by 00z/Sun, showers potential will also expand across the se
half of Upper Michigan. However, since the stronger forcing remains
farther to the se, only chance pops were mentioned. Despite the
thicker clouds over the area, high temps will remain above normal
with highs in the low to mid 60s.
.LONG TERM...(Saturday night through Friday)
Issued at 334 PM EDT FRI SEP 30 2016
Deep mstr arnd a slow moving closed lo pres in the Lower Lks could
cause some showers over the se half of Upr MI on Sat ngt into Sun,
but then an upr rdg shifting into the area wl bring dry wx into at
least Wed. The biggest uncertainty wl be on sky cover/potential for
lo clds during this time. As the cold fnt ahead of a deep, slow
moving wrn trof moves toward the area, shower chcs wl return later
in the week. Unseasonably warm air wl dominate the Upr Lks until
late next week, bringing continued above normal temps to Upr MI.
Sat ngt/Sun...Closed upr lo over far srn Lower MI on Sat evng is
fcst to lift slowly to the ne and thru far se Ontario on Sun.
Although the models are consistent showing a good deal of mstr
extending into the Upr Lks within the deep cyc ne flow on the nw
flank of this disturbance, the bulk of the larger scale deep lyr
cnvgc is progged to remain mostly to the se closer to the track of
the closed lo and impact only the ern portion of the cwa. Even this
forcing is progged to exit to the e on Sun as the closed lo drifts
in that direction away fm Upr MI. So the fcst wl continue to show no
more than chc pops over the se half, hiest on Sat ngt toward the
LOT/APX cwas and diminishing on Sun. Expect temps thru the weekend
to remain above normal, especially on Sat ngt with lots of clds in
the presence of h85 temps arnd 9C. The best chc for more sunshine on
Sun wl be over the w closer to slowly aprchg hi pres rdg axis if lo
clds associated with persistent near sfc mstr in that area do not
linger. Max temps on Sun should run mainly in the 60s even though
more persistent clds toward the e wl limit insolation.
Sun ngt into Wed...As the upr rdg to the e of a deep wrn trof shifts
into the wrn Great Lks early next week, a sfc rdg axis extending
swwd fm a hi pres center drifting fm over Hudson Bay into Quebec wl
dominate the Upr Lks. On Tue and Wed, this rdg wl shift the e,
causing a tightening pres gradient/strengthening sly flow over the
cwa to the e of falling mslp in the Plains associated with the
slowly progressive wrn upr trof. While dry wx wl prevail during
this time with larger scale subsidence under the upr rdg, some of
the medium range models have hinted at some lo clds/fog under
strengthening subsidence invrn with lgt ne winds off Lk Sup on Mon
and then the sly flow off Lk MI on Tue/Wed at a time of the year
dominated by lowering sun angle/diminished daytime mixing/longer
nocturnal cooling. The potential for this lo cld cover is the
biggest uncertainty during this period. Fcst h85 temps arnd 9C
rising toward 12C on Wed wl ensure temps run abv normal during this
time, but the presence or not of lo clds would alter the min/max
temp anomalies and diurnal ranges. Best chc for anomalously warm
daytime max temps wl be on Tue/Wed in the downslope areas near Lk
Sup, where the prospect for more sunshine wl be greatest and
could lift daytime max temps aoa 70.
Wed thru Fri...Although there remain some timing differences on how
quickly the wrn trof and cold fnt attendant to associated lo pres
lifting into scntrl Canada wl move toward the cwa, shower chcs wl be
on the incrs on Wed/Thu as this fnt/warm conveyor belt mstr ribbon
aprch. Some of the longer term guidance generates a good deal of
pcpn over the area, not out of the question considering pwats fcst
to rise as hi as about 1.50 inches under the warm conveyor belt and
relatively slow ewd progression of the features that would extend
residence time of the stronger sly flow/deeper mstr. On the other
hand, some of the models show the more sgnft hgt falls passing to
the nw with lighter pcpn over the wrn Great Lks. Considering these
important differences, ll not deviate fm the consensus fcst.
Following the eventual cold fropa, looks like much cooler air wl
invade the area late in the week. The 00Z ECMWF shows one of the
coolest scenarios with h85 temps dipping blo 0C by late Fri and
supporting some lk enhanced pcpn under lingering moist cyc nw flow.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 151 PM EDT FRI SEP 30 2016
Expect VFR conditions will continue to prevail through this evening
under the influence of dry high pres over nrn Ontario. Some
radiationa fog will be possible late tonight at IWD.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 416 PM EDT FRI SEP 30 2016
A weak pressure gradient across Lake Superior through the weekend
and early next week will keep east to northeast winds at 20 kts or
less. South-southeast winds may increase over 20 kts Tue into Wed
ahead of front moving out the Northern Plains. Strongest winds would
be over north central and eastern Lk Superior.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...- None -
LONG TERM...KC
AVIATION...JLB
MARINE...- None -