Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/02/16
Area Forecast Discussion
National Weather Service Binghamton NY
825 PM EDT Sat Oct 1 2016
.SYNOPSIS...
Unsettled weather will continue for the remainder of this weekend
into Monday as a slow moving upper level low dominates our
weather. This low will keep a chance for showers in the forecast
through Monday evening. Drier conditions are expected to return by
the middle of the week as high pressure takes control.
&&
.NEAR TERM /THROUGH SUNDAY/...
815 pm update...Showers with even some embedded thunder currently
moving through central NY and this has been resulting in some
brief very heavy downpours putting down a quick half to three
quarter inches of rain in spots. We made some adjustments to
POP/QPF for the evening based on latest radar and trends. Main
idea was raising both POPs and QPF and also adding in mention of
thunder. Showers are moving fast enough that we are not expecting
any hydro issues.
330 pm Update...Radar imagery shows showers mainly over central
and north central PA early this afternoon associated with a plume
of moisture seen on the water vapor imagery. This moisture was
associated with a short wave that was riding north on the east
side of the upper level low over northern Indiana. These showers
will move north for the rest of this afternoon and affect mainly
the central southern tier of NY, western Finger lakes of NY and
Bradford county PA in the BGM forecast area. So have chance to
likely POPs in these areas for the rest of the afternoon.
For this evening, followed the HRRR which eventually brings this
plume of moisture and associated showers farther east to the I-81
corridor by around 00z-02z and then to the Catskills to upper
Mohawk Valley by 06z. Leaned heavily on the HRRR for hourly POP
timing. Used HRRR, plus blended with neighboring offices. Also
broadened the chances for light precipitation tonight as there
will be patchy drizzle as well with continued low-level south-
southeasterly flow and upsloping. Hence keep overcast skies in
through the night as there is little chance for any significant
breaks in the overcast to form given the present low-level flow
pattern. After 06z see just patchy drizzle or light showers and
have trended down POPs from west to east. Highest chances for
precipitation will be in the Catskills to upper Mohawk Valley late
tonight where there will be the most upslope.
Then for Sunday, low-level winds turn more southwesterly which
should lead to some breaks in the overcast. The upper level low
moves east and reaches the eastern Great Lakes between 21Z and
00Z. This will lead to more showers spreading into the Finger
Lakes late in the day. With the lower clouds breaking up chances
for drizzle will wane Sunday morning.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
3 PM Update...
Good model agreement with an upper level low moving slowly east
across upstate NY Sunday night to Monday night. Showers will
remain across the area into Monday evening. Some diurnal
thunderstorms also possible in the afternoon and evening both days
with some surface heating and cold air aloft. Best chances of
showers and thunderstorms in central NY. Rainfall less than half
an inch for this period. Deeper moisture stays to the southeast of
the cwa.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
3 PM Saturday update...
Forecast adjusted towards blend of latest models. Tuesday to
Thursday surface high pressure and a building ridge aloft.
Temperatures stay above normal.
Thursday night into the weekend has much uncertainty. Hurricane
Matthew is moving north up the east coast. By Wednesday WPC has
this off of North Carolina. GFS has a faster and further west
track while Euro is off the coast with rain not in the CWA. The
Canadian is wide right. The track will greatly depend on the speed
of the approaching upper level trough and surface cold front. This
cold front in central NY and central PA on Saturday.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Periods of rain/showers will affect the sites over the next 24
hours bringing restrictions. For this evening, area of showers is
moving through as of 0z and this may bring brief restrictions to
IFR mainly due to reduced visbys in heavy downpours. Otherwise,
generally expect MVFR conditions to persist in most places through
mid evening. However by late evening into the overnight, showers
will be winding down but moist SE flow will result in lowering
cigs with KAVP/KBGM/KELM/KITH dropping to IFR between 02-06z. In
fact cigs may even dip below alt mins overnight especially at KBGM
and KELM. KRME should drop to IFR cigs late tonight while KSYR
stays predominate MVFR cigs with tempo IFR near sunrise. For
Sunday, the flow will shift from SE to S/SW from west to east and
this will result in cigs beginning to lift. KSYR/KELM/KITH should
lift to low VFR by 17z while remaining sites to the east stay MVFR
most of the day.
Winds E/SE 5-10 knots tonight shifting to S/SW Sunday.
OUTLOOK...
Sun night-Monday...Occasional restrictions possible from lower
ceilings and scattered showers.
Tuesday-Thursday...Mostly VFR. Early morning fog possible at
KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/PCF
SHORT TERM...TAC
LONG TERM...TAC
AVIATION...DJN/PCF
Area Forecast Discussion
National Weather Service Caribou ME
1009 PM EDT Sat Oct 1 2016
.SYNOPSIS...
Low pressure will track southeast of the Gulf of Maine tonight
into Sunday. An upper level low will cross the region Sunday night
into Monday. High pressure will build across the region later
Monday through mid week.
&&
.NEAR TERM /THROUGH SUNDAY/...
930 PM Update... Adjusted the POPs northward a bit after midnight
as the HRRR and RAP both show some precip getting up toward
Houlton, as well as northern Penobscot and Piscataquis. This
matches up with both models showing a ribbon of higher 500mb
vorticity drifting up that way. Didn`t make huge changes, but did
introduce 25-30 POPs and sct shwrs as far north as Houlton and
Patten. However, rather dry layer below 750mb across much of the
CWA may limit how much of the radar returns actually reach the
ground, but overall expected moistening of the column will likely
lead to at least some drizzle or light rain in many spots. Did
also adjust QPF accordingly to introduce some QPF further north,
but didn`t change much toward the coast. Tweaked temps and dewpts
for current conditions, and did adjust lows a bit by blending prev
fcst with BC`d MOS consensus. Adjusted immediate sky conditions a
bit cloudier as well, but keep the chance for some pre-dawn
clearing up north.
Previous Discussion...
The models are in good agreement through the period. A high
pressure ridge will dominate the weather for much of the area
through the forecast period. A low over northern Kentucky with a
frontal system extending east into the north Atlantic through the
Cape Cod area. The warm front will move slowly north through the
period and will be over southwestern Maine and most of the Gulf of
Maine by the end of the period. A new low will form on the front
near Cape Cod by the end of the period.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
A weakening upper low will move across the region Sunday night
into Monday. Surface high pressure will begin to build south
across the region later Monday. Expect a slight chance/chance of
showers Sunday night, with the better chances across western
portions of the forecast area. Cloud cover will decrease across
northern areas Monday with building high pressure. Skies will
remain mostly cloudy Downeast Monday, with a chance of mostly
morning showers. High pressure will build across the region
Monday night through Tuesday. Expect mostly clear skies across
northern areas Monday night with decreasing clouds Downeast.
Mostly sunny skies are expected across the entire region Tuesday.
Temperatures will be at near normal levels Monday/Tuesday.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Quiet weather expected in this period as mid and surface high
pressure becomes anchored over the Northeast quadrant of the
CONUS. No real chance for rain through the Friday period, with
the chance for precipitation increasing by next weekend. There is
huge spread in model solutions in regards to Matthew at this
point, just went with a general chance for showers at this point
on Saturday. Temperatures will run above average this time of
year, especially Wednesday on as dewpoint temperatures increase,
preventing temperatures from dropping to normal lows. Could be a
valley fog pattern next week due to this.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: Aviation VFR conditions will continue for FVE, CAR,
PQI, and HUL through the period. VFR conditions for BHB and BGR
with light rain around the area. Ceilings will be above 6000 Ft to
start the period falling to around 3000 ft around midnight. After
midnight prevailing ceiling of 3000 ft will be further reduced in
precipitation to around 1500 ft for BHB and around 2500 for BGR as
a warm front and low passes to the south of the area. Conditions
will slowly improve towards the end of the period.
SHORT TERM: Occasional MVFR conditions are possible across mostly
central and Downeast portions of the region Sunday night into
early Monday, with VFR conditions across northern areas. VFR
conditions are expected across the entire region later Monday
into Wednesday.
&&
.MARINE...
NEAR TERM: An SCA for seas will be in effect from 4 AM to 1 PM
Sunday as a low pressure area tracks southeast of the Gulf of
Maine. Winds will increase to around 15 kts with gusts to around
22 kts during this time frame. Winds and seas below SCA during
other times during the period.
SHORT TERM: Conditions are expected to be below small craft
advisory levels Sunday night through Tuesday. Visibilities could
be reduced in any showers later Sunday night into early Monday.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory for hazardous seas from 4 AM to 1 PM EDT
Sunday for ANZ050-051.
&&
$$
Near Term...Hewitt/Kredensor/Norton
Short Term...Norcross
Long Term...Dumont
Aviation...Hewitt/Kredensor/Norton/Norcross
Marine...Hewitt/Kredensor/Norton/Norcross
Area Forecast Discussion
National Weather Service Cleveland OH
934 PM EDT SAT OCT 1 2016
.SYNOPSIS...
Low pressure over northern Indiana will lift north into lower
Michigan overnight then shift east into Ontario on Sunday and to
New England on Monday. A large area of high pressure will move
across the Great Lakes Monday and move off the New England Coast
late Tuesday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Scattered showers and a few embedded thunderstorms have been noted
on radar over the last several hours. As surface and upper level
low pressure system begin to slowly move east over Lake Erie, We
will continue to see a threat for scattered showers and
thunderstorms. 850 mb temperatures drop to between 6 and 8 degrees
C overnight making it cooler aloft. This should help to bring a
few more thunderstorms to the area with the cooler air aloft. Will
keep the chance with isolated wording mentioned for the
thunderstorms. No major changes to gridded forecast.
Previous Discussion...
With the close proximity of the upper low
now over northern Indiana we can expect scattered showers with
isolated thunderstorms to continue or develop this evening. For
the next few hours before sunset...the highest coverage and
likelihood of showers will be over northwest Ohio where
instability is greatest and also over north central Ohio as a
small vorticity lobe seen in the water vapor over central Ohio
lifts north. Later in the evening...the confidence in timing and
location of convective development is lower. The HRRR has varying
amounts of showers with little run to run consistency so again
confidence is low. Overall guidance POPs are high but specific
triggers are difficult to discern. Will continue with chance to
likely POPs overnight with the higher POPs in the northeast.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
Gradual improvement in the weather can be expected during this
period as the upper low departs the region. The center of the
upper low will be near DTW on Sunday morning and move to near SYR
on Monday and off the New England coast on Tuesday. As the upper
low moves away, drier more stable conditions will develop and
decrease the chance for rain. On Sunday morning we can expect the
highest POPs over northeast Ohio and nw PA with a gradual decrease
during the day. Further drying can be expected Sunday night and
early Monday with just a lingering shower over mainly northwest
PA. Finally by Monday afternoon the forecast should be dry as high
pressure fully builds into the region. Fair weather will continue
Tuesday and Tuesday night.
Temperatures on Sunday will be just a tad cooler than today as
850mb temperatures will be 2-3C degrees cooler. A slow warming
trend can then be expected with readings at 850 mb warming to
around 12C which will boost surface max temperatures into the 70s
for Tuesday.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The next cold front will approach the area later in the week. It
looks as though most of the models are showing a weakening front
advancing across the northern Great Lakes on Thursday. This front
will likely not cross the forecast area or perhaps just the
dissipating version of the front. Then we wait for a stronger front
to arrive.
The second front may get here on Saturday although not a lot of
confidence yet until we get the east coast tropical system out to
sea. Cannot rule out a shower getting to northwest Ohio on Thursday
but will cut back the pop to "slight chance" for Thursday across
northwest Ohio. A somewhat better chance for showers Friday night
into Saturday but will keep the pops modest for now given the
uncertainty on the timing of the front.
Raised forecast temperatures through Friday given the potential
slower arrival of the front. Highs in the 70s, could turn out to be a
real nice week.
&&
.AVIATION /00Z Sunday THROUGH Thursday/...
Low pressure over northern Indiana will move east across Lake Erie
on Sunday. Scattered showers remain possible at all terminals but
will continue to be hard to time. By Sunday afternoon, higher
chances of showers will be focused across northeast Ohio/northwest
Pennsylvania. Conditions are VFR at all sites to start the TAF
cycle with MVFR ceilings/visibilities likely at several sites in
the 08-13Z window. Ceilings should improve quickly on Sunday
except possibly down wind of the lake at ERI. Light south to
southeast winds tonight with shift to the southwest/west on
Sunday.
OUTLOOK...MVFR possible at times Sunday night and Monday.
&&
.MARINE...
Weakening low pressure will drift across Lake Erie later tonight
and early Sunday and winds will veer from southeast to southwest.
There may be enough surface convergence for waterspouts but not
enough confidence to put them in the forecast and will have to
monitor the possibility.
High pressure will build across the lake early in the week and
ridging will persist through at least mid week. Winds will veer from
northwest to northeast and eventually southeast but remain relatively
light.
The next cold front will arrive late in the week but no confidence
on the timing yet.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...DJB/LaPlante
NEAR TERM...LaPlante/Lombardy
SHORT TERM...LaPlante
LONG TERM...Kosarik
AVIATION...KEC
MARINE...Kosarik
Area Forecast Discussion
National Weather Service Wilmington NC
1051 PM EDT Sat Oct 1 2016
.SYNOPSIS...
A stationary front will waver along the coast through this
weekend, with shower and thunderstorm chances becoming confined
to the immediate coast. Weak high pressure will build in with
drier weather forecast early next week. The official NHC forecast
continues to bring Hurricane Matthew into the Bahamas on Wednesday,
bringing increasing waves and a heightened rip current risk to the
local beaches.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 1045 PM Saturday...This afternoon`s seabreeze merged with
the synoptic front and the two of them pushed inland to the
Interstate 95 corridor between Florence and Lumberton before
stalling this evening. The depth of moisture is obviously greater
than models are seeing given the continual redevelopment of
convection along this boundary. A mesonet station in Pembroke, NC
(Robeson County) has picked up a whopping 1.25 inches of rain this
evening. New cells near Dillon and Lumberton are moving north-
northeastward and I have been forced to issue updates to extend
high PoPs with this narrow zone of convection for the next couple
of hours. At some point soon the boundary should begin to push
eastward toward the coast. I am watching dewpoints closely in
Florence to see when this movement may begin, but there is yet no
sign of this movement.
More scattered showers developing across the warm Atlantic waters
east of Myrtle Beach should continue to advect onto the Brunswick
and New Hanover county coastline tonight. I have bumped PoPs up to
as high as 30-40 percent here. Although the HRRR has not
initialized well, it shows an expansion in coverage of showers
between 2-3 AM as the synoptic front may reach the SC beaches,
adding lift to the better instability that exists offshore.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
As of 400 PM Saturday...Anomalous upper low across the OH Valley
will, finally, eject slowly to the NE through the short term,
weakning and moving out of New England by the end of the period.
This will finally allow the cold front which has been plaguing this
area to push offshore, allowing drier and slightly cooler air to
filter all the way to the coast. While Sunday will still feature the
front wavering in the vicinity, by Monday it should lift enough to
the E/NE to bring drier weather to the coast as well. Will note that
the NAM keeps the front closer and has a wave of low pressure
develop with some showers on Monday, but this has been overdoing the
precip today and the GFS is preferred. This suggests gradually
lowering pop to silent through early week with continued nice fall
weather inland, and improving to seasonable norms at the coast.
Highs both days will still rise into the 80s, warmest inland, with
lows falling into the 50s inland, 60s at the coast.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 400 PM Saturday...High pressure will continue to build
into the area Tuesday into Wednesday which will allow for fairly
dry conditions inland for early to mid-week. As for the coastal
areas, onshore flow will continue to provide available low level
moisture for isolated showers each day. For the rest of the
forecast period, confidence remains low as all eyes remain on
Hurricane Matthew and it`s projected track. As disagreement
continues with the latest guidance, have only tweaked the
forecast for now, keeping with the potential for marine threats
at this point for increased waves, rip currents and minor coastal
flooding. High temperatures in the upper 70`s will continue
through the week, with overnight lows in the mid 60`s.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 00Z...Generally expect VFR conditions through much of the
taf period. There is an outside shot that a shower could affect
the coastal terminals in the next two to three hours.
Additionally, we could see a repeat performance regarding fog and
stratus tonight. Conditions forecast in the terminals are largely
based on persistence with IFR conditions possible at ILM and LBT
and MVFR at CRE and MYR. VFR conditions should develop rapidly
after sunrise, especially inland.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 1045 pm Saturday...Last night`s cold front pushed back
inland today and is currently stalled near Interstate 95 from
Florence to Lumberton. Model suggest the front will slowly push
eastward overnight and should reach the beaches late, spreading
light westerly winds across the coastal waters by sunrise. Ahead
of this front, southerly winds around 10 knots should continue.
Scattered showers are developing in the warm and unstable airmass
ahead of the front. These are moving steadily northeastward and
should move onshore from Oak Island and Bald Head Island, also
affecting the coastal waters in the Cape Fear area.
Seas are around 4 feet north of Cape Fear and in the Frying Pan
Shoals area, around 3 feet to the south. Spectral wave analysis
shows wave energy is evenly split between a 6-second southerly
wind wave and an 11 to 12 second east-southeasterly swell.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 400 PM Saturday...Cold front along the coast will stall and
waver across the coastal waters Sunday before finally pushing
offshore Monday as high pressure ridges down from New England. This
will keep winds Sunday light and variable, before shifting to the NW
and then increasing within a NE surge to 15 kts late Monday. Seas
will feature a 2-3 ft/8sec SE swell both days, but will become
increasingly wind-wave dominated, rising from 2-3 ft to 3-5 ft by
the end of the period.
LONG TERM /TUESDAY THROUGH THURSDAY/...
As of 400 PM Saturday...Small Craft Advisory possible by midweek.
North-northeasterly winds will continue through the
period, increasing to around 15 to 20 kts Tuesday into Wednesday.
Wednesday evening, winds increase to around 25 kts in the outer
waters. As for seas, 3 to 5 ft on Tuesday will shift to 4 to
6fters on Wednesday,with higher seas in the outer waters possible.
Things may change as we continue to monitor the track of Hurricane
Matthew, but will continue to monitor swell from the system.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...SGL
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...SGL
AVIATION...RAN
Area Forecast Discussion
National Weather Service Wilmington OH
919 PM EDT Sat Oct 1 2016
.SYNOPSIS...
An upper low will drift slowly northeast through the Great Lakes
this weekend. Under the influence of this upper low expect cool
temperatures and a chance for showers through Sunday. A warmer
and drier airmass will build into the region through the middle
part of next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
The upper level low continues to spin as it slowly lifts north
and is currently centered near the Indiana/Ohio/Michigan border.
Embedded pockets of energy rotating around the low is helping
to keep some isolated to scattered shower activity going across
the region. Will nudge up pops a bit through the near term to
account for this and even allow for a brief period of likely pops
across the northwest where some more concentrated showers should
rotate through over the next couple of hours. We could see some
partial clearing through early morning but the models are
suggesting some possible stratus and fog development later tonight.
Will continue with lows generally in the lower 50s for tonight.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Upper low drifts across the eastern Great Lakes and into the
Northeast states through Monday.
Influence from the upper low is expected to be less on Sunday.
After morning stratus, there may be some breaks in the clouds by
afternoon. Still can`t rule out a few showers, but coverage
should be more sparse and mainly in the isolated category on
Sunday. Dry weather and more sunshine are then expected for
Monday as the flow becomes increasingly anticyclonic.
Warming trend should also begin with highs near 70 Sunday and in
the lower to possibly mid 70s for Monday. Lows will be slightly
above average, favoring lower to mid 50s both Sunday night and
Monday night.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Upper level ridge extending from New England into the Gulf of Mexico
will keep dry and warm conditions across the region into Thursday. A
trough will move from the Plains into the Great Lakes and Ohio
Valley late in the week. 12Z models continue to show discrepancies
in timing which may be related to the handling of Hurricane Matthew
off the Atlantic coast. Have leaned toward ECMWF for timing which
would push a cold front through the region on Friday with a chance
of post-frontal showers. This will bring temperatures down closer to
normal by Saturday.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
Isolated to scattered shower activity is continuing to rotate around
the upper level low that is slowly lifting north into the southern
Great Lakes region. As we continue to lose the daytime heating,
expect to see some decrease in coverage through the overnight
hours. That being said, the RAP and the HRRR are suggesting that a
few showers may continue to affect at least the northern TAF sites
through the late evening and possibly into the early morning
hours. Otherwise, expect some MVFR to occasionally IFR cigs and
vsbys to redevelop once again later tonight into Sunday morning.
The upper level low will begin to shift more quickly off to the
east across the southern Great Lakes through the day on Sunday.
This could result in a few lingering showers, especially across
the north. However, the chance appears low enough to leave any
mention out of the TAFs for Sunday. Cigs should gradually lift
into VFR category as we head into Sunday afternoon.
OUTLOOK...No impacts to aviation expected.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...BPP
NEAR TERM...JGL
SHORT TERM...BPP
LONG TERM...
AVIATION...JGL
Area Forecast Discussion
National Weather Service Lincoln IL
1051 PM CDT SAT OCT 1 2016
.UPDATE...
Issued at 838 PM CDT Sat Oct 1 2016
The upper low that has plagued the Midwest for the past several
days bringing low clouds and scattered showers to our area was
edging slowly into southern lower Michigan early this evening.
Area still under the influence of the broad cyclonic flow from the
low with widely scattered showers occurring over parts of the area
this evening. We do expect those to end over the next few hours
with the main forecast challenge being the threat for some dense
fog late tonight. Still seeing some mid level clouds swirling
south around the upper low into our area which may tend to keep
the fog from getting to thick and widespread. Early evening dew
points were in the upper 50s to lower 60s, which was only a few
degrees from the current temperatures so any clearing overnight
should produce a quick reduction in visibilities. The HRRR since
late this afternoon has been quite aggressive in lowering the
visibilties across our area after midnight so will continue the
trend in bringing the fog in late tonight with areas of dense fog
possible during the early morning hours.
Have made some adjustments to the showers in the grid, extending
the threat through about 10 pm before the threat shifts off to our
east. We should have the updated zones out by 900 pm.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 246 PM CDT Sat Oct 1 2016
Upper low inching its way northward toward the northeast tip of
Indiana this afternoon. Scattered showers continue to rotate
southeast across the state as the next spoke of energy drops
southward across the Chicago metro. So far the thunder has pretty
much stayed across Indiana, but has approached the Illinois border
at times north of Danville. These will largely diminish with loss of
daytime heating, and have mainly gone with isolated early evening
showers, with slightly higher PoP`s north of I-74. With a light wind
flow and still plenty of low level moisture, areas of fog are likely
across most of the forecast area late tonight into Sunday morning.
Will have to monitor closely to see if dense fog will form, as
indicated by some of the higher resolution model guidance.
Upper low will track into southern Ontario Sunday morning, pulling
most of the showers with it. Most of the afternoon model guidance is
showing some isolated showers across southern Illinois, associated
with a weak trough trailing the low. Have added some small PoP`s
over the far south/southwest CWA early Sunday afternoon, but dry
weather will be the general rule. With an extensive cloud field
lingering, temperatures will rise a bit tomorrow but not get out of
hand, with lower 70s prevailing.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 246 PM CDT Sat Oct 1 2016
The upper level ridge behind our departing cut-off low will start to
move overhead Sunday night bringing quite calm winds and potential
for fog development as moisture remains trapped below weak
subsidence aloft. The ridge will remain over Illinois through Monday
providing fair weather with morning fog and stratus scattering out
to partly cloudy afternoon skies with afternoon heating.
An approaching longwave trough will initiate more of a southerly
flow Tuesday to Wednesday for an increasing temperature trend and
less cloudy skies. 12Z GFS/ECMWF have come into better agreement
ejecting a series of shortwaves and associated precipitation through
mainly western and central IL Wednesday through Thursday followed by
a delayed cold frontal passage early Friday. Therefore, have dry
conditions over IL through Wednesday morning then focused PoPs on
these areas with highest PoPs from I-55 west with around 60%
Wednesday night followed by 30-50% across most of central IL
Thursday and Thursday night. PoPs then slowly taper off to slight
chances Friday into Friday night. Highs Monday should range from the
low to mid 70s, increasing to the low 80s on Wednesday, followed by
cooling back to slightly below normal, or 65 to 70 degrees for
Friday and Saturday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1050 PM CDT Sat Oct 1 2016
Little change from previous thinking with the main forecast
concern being the potential for dense fog with IFR to LIFR
cigs/vsby into the mid morning hours of Sunday. Fog already
starting to develop in parts of west central Illinois late this
evening and expect this trend to continue overnight. Any areas
that have or do experience and brief period of clear skies
overnight may see more widespread dense fog early Sunday morning.
Forecast soundings suggest a rather shallow layer of moisture so
it appears the fog/low vsbys and stratus should begin to improve
after 14z with scattered to broken cumulus developing by late
morning/early afternoon with cig bases in the 4000-5000 foot level
by afternoon. Winds once again will not be much of a factor with
light and variable winds tonight and a light northwest wind
expected on Sunday with speeds less than 10 kts.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Smith
SHORT TERM...Geelhart
LONG TERM...Onton
AVIATION...Smith
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1105 PM EDT Sat Oct 1 2016
.UPDATE...
Issued at 1055 PM EDT SAT OCT 1 2016
A band of showers is rotating from the Bluegrass counties into
northeastern KY. Pops were updated for the next couple of hours
accordingly. Otherwise, no other changes were necessary at this
time.
UPDATE Issued at 815 PM EDT SAT OCT 1 2016
A band of showers is rotating from central into parts of eastern
KY at this time. Hourly pops have been increased across the
northwest part of the area for the next few hours. Also, hourly
temperatures and dewpoints have been adjusted slightly based on
recent observations. If and where clearing occurs later on
tonight, dense valley fog should again develop.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 315 PM EDT SAT OCT 1 2016
18z sfc analysis shows low pressure still holding over the Ohio
Valley beneath a gradually exiting upper low. These features have
been responsible for the plenty of clouds through the area once
again this afternoon along with sprinkles and a couple of
showers, though these were mainly confined to the northern and
western portions of the JKL CWA. Temperatures have made it into
the mid to upper 60s through the area while dewpoints are
generally in the low to mid 50s with light/variable winds.
The models are in good agreement aloft through the bulk of the
short term portion of the forecast. They all slowly take the deep
closed low north from the Ohio Valley and into the eastern Great
Lakes on Sunday. At this point, the model spread increases a bit as
the CMC scoots the low east faster than the consensus and has been
discounted - though the latest ECMWF seems to be a tad more
progressive than the rest, too. The departure of this closed low
will take its mid level energy with it, but not before Sunday
evening for most of the area allowing limited support for pcpn
around through the rest of the weekend. Given the model agreement
will favor a general blend with a lean toward the HRRR and NAM12
in the near term and some persistence mixed in.
Sensible weather will feature another cool and cloudy night with
sprinkles and a few showers around, similar to last night. Also,
like last night - anticipate fog for the valleys with locally
dense patches forming toward dawn. More clouds will be around on
Sunday with another potential for showers during the afternoon,
though most places will stay dry. Temperatures should be a notch
higher, as well. Look for another cool night into Monday morning
with a bit less in the way of clouds and as a result better
radiational conditions likely leading to more fog.
Used the CONSShort and ShortBlend as a starting point again for
most grids into Sunday morning with the SuperBlend used
thereafter. Made just some minor changes to the T grids based on
terrain with the clouds around tonight and slightly more changes
Sunday night. As for PoPs - ended up on the low side of a MOS
blend - closest to the MAV - through Monday morning.
.LONG TERM...(Monday through Saturday)
Issued at 300 PM EDT SAT OCT 1 2016
The extended portion of the forecast will be mostly dry, with very
pleasant temperatures through out. A ridge of high pressure will
influence the weather of eastern Kentucky through Thursday, with
partly cloudy to mostly clear skies and light winds expected across
our area. High temperatures each day through Thursday are forecast
to top out in the mid to upper 70s. A few locations may reach or
slightly exceed 80 degrees Tuesday through Thursday along and south
of the Hal Rogers Parkway and Highway 80 corridor. A cold front is
expected to move through the area Thursday night, bringing a few
rain showers to eastern Kentucky. Any lingering rain showers should
be exiting the area by late Friday morning. A much cooler air mass
is then expected to settle over the region to finish out the week.
Highs on Friday should be close to normal, with max values in the
low to mid 70s on tap. Nightly lows should bottom out in the 50s,
with readings in the mid to upper 40s possible for Friday morning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 830 PM EDT SAT OCT 1 2016
The upper level low continues to meander from the Ohio Valley
toward the Great Lakes. This is bringing bands of clouds and the
bands of showers/sprinkles to parts of the OH valley, although
the more substantive of these should remain north of the area.
Mainly VFR conditions will be the rule through the first few hours
of the period period with the exception of the far north and west
where stratus or stratocu are expected to develop overnight. This
should bring some MVFR or IFR CIGS to those areas including SME
and SJS between 6Z and 16Z. Elsewhere for the TAF sites, MVFR fog
is anticipated with IFR in deeper valley locations. The fog and or
low clouds should lift and dissipate by 16Z, with VFR conditions
and light and variable winds then prevailing through the end of
the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...JP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
906 PM CDT Sat Oct 1 2016
.UPDATE...
905 PM CDT
For evening update...
Going forecast appears largely on track this evening. Had made
some hourly pop/wx tweaks based on radar trends and shower
coverage, and did add an isolated thunder mention over southern
Lake Michigan this evening. Otherwise, no significant changes made
at this time. Also issued a marine weather statement for isolated
waterspout potential with development of weak lake-induced
convection next few hours as described below.
Evening water vapor imagery depicts closed upper low over northern
Indiana was starting to become more elongated from west-east, and
was beginning to shift off to the east. Axis of better 925-850 mb
moisture was north of the area across northern MI/Lake Michigan,
with showers becoming less numerous across the cwa. The exception
was across far southern Lake Michigan, where RAP analysis
indicated some weak lake-induced instability, where isolated to
scattered convective showers were developing. 00Z AMDAR aircraft
ascent sounding from ORD, modified for surface conditions at mid-
lake buoy, yielded a little over 400 J/kg of SBCAPE, supporting
RAP instability field. This weak instability, and a weak
convergent axis between northeast winds over open waters and
northerly winds along the shore will likely continue to produce
some isolated showers and a brief rumble of thunder through
midnight or so, before low level winds back more north-northwest
as the surface low moves slowly to the east-northeast. Overall
however, shower coverage should be fairly minimal farther to the
west, with higher chance pops focused across the lake and
northwest Indiana overnight.
Otherwise, have observed some decrease in high/mid cloud deck in
spots with forcing/moisture decreasing aloft. Would expect any
partial clearing to fill back in with low stratus and potentially
some fog given moist low levels and weak cyclonic flow. Fairly
uniform temperature field expected to persist in the upper
50s/around 60 degree range, though could see a few lower values
where clouds temporarily clear.
Ratzer
&&
.SHORT TERM...
300 PM CDT
Through Sunday...
We begin to finally see a shift in the weather system that has
impacted the weather much of this past week. This will mean
diminished rain chances, however the clouds are likely to stick
around, as will some potential for nightly fog. Brighter autumn
weather will arrive this coming work week.
The closed upper low is centered over northeast Indiana this mid-
afternoon and will continue to track northeast into tonight.
Corridors of forcing continue to rotate around this with
associated bands of showers, some of which are quite efficient
and temporarily heavy. Lightning in any shower activity this
afternoon has been confined to near the low center. Unlike recent
nights, the waves of forcing will becoming further spread out and
weaker, so chances for light showers look quite low by 9 pm or
so, and mainly in eastern areas.
Clouds should once again fill in during the evening with fairly
moist and light flow low-levels. Last night realized scattered holes
in that cloud shield, although those filled in with fog. Think
there is potential of that again tonight and have added patchy fog
wording overnight. Those areas that do see clearing would likely
see mid 50s, while those that stay completely cloud covered could
did to only around 60.
MTF
&&
.LONG TERM...
335 PM CDT
Sunday night through Saturday...
The upper level low high tails it to the northeast allowing high
pressure to build in Sunday night and Monday. Sunday night through
Tuesday night will be dry with a warming trend.
Attention then turns to the front that arrives mid week. The ECMWF
remains faster than the GFS, but the two are much closer than they
were 24 hours ago. Expecting a dying line of showers and storms to
spread east across the area Wednesday. The cold front lags well
behind the line. There should be ample cloud cover so have low
confidence in how long the storms will last and additional storm
development. The ECMWF has caught on to what the GFS has been
showing for a few days that scattered showers and perhaps some
storms will continue Wednesday night into Thursday. The GFS
features more upper level vort streamer support than the ECMWF.
The cold front finally comes through early Friday morning with the
final round of showers and storms. The GFS keeps precip over the
region into early Saturday morning while the ECMWF quickly pushes
the precip through Friday. With high pressure building in behind
the cold front, thinking the ECMWF`s timing is more realistic.
The severe outlook remains low for mid to next week as the models do
not feature a lot of CAPE. With the prolonged nature of the showers,
are more concerned that a potential flooding event may occur
depending on how strong and persistent the showers are.
For temps: temps warm while we sit under the upper level ridge
through Wednesday. High`s Wednesday will be in the upper 70s to low
80s and maybe even higher depending on cloud cover. Much cooler
upper level air moves in behind the cold front bringing us back to
more fall like temps in the 60s.
JEE
&&
.AVIATION...
For the 00Z TAFs...
Upper low is beginning to pull away from the region; however, low
ceilings and a few festering showers will remain over northern
Illinois and northwest Indiana this evening and tonight. Shower
coverage should continue to diminish through sunset, and think by
mid to late this evening that terminals should be dry. There is a
lot of variability in ceiling heights over the region this
evening, and while some spots may bounce up to VFR briefly this
evening, low stratus is expected to expand over the region late
this evening and tonight with lowering ceilings through the
predawn hours. Several models are suggesting we could fall to
LIFR/VLIFR early tomorrow, but guidance has in general been too
pessimistic the past couple nights. Expect diurnal improvement in
ceiling heights through the day tomorrow. As the low departs east,
high pressure will build into WI tomorrow causing winds to turn
back to the NE tomorrow afternoon.
BMD
&&
.MARINE...
303 PM CDT
Low pressure that has been anchored just south of the Great Lakes
region the past several days will begin to move northeast over the
eastern Great Lakes during Sunday. Winds will turn more
northwesterly in response. The pressure gradient is not that sharp
on the backside of this system, so only expecting some gusts to 20
kt. Winds will be light on Monday then turn southerly on Tuesday.
As for the threat of waterspouts tonight, the threat is certainly
less than it was this past Wednesday when numerous were seen, but
it does exist and there have been a couple surface boundaries
noted over/near the lake. So have a general marine weather
statement through this evening for the southern part of the lake
noting that possibility.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Melbourne FL
853 PM EDT SAT OCT 1 2016
.DISCUSSION...
Rest of Tonight...The HRRR model has done a good job capturing
the convective essence of the quasi-stationary boundary in
vicinity if the I-4 corridor late this afternoon and evening. The
boundary has been quite productive with rainfall, especially
across parts of southwest Seminole and northwest Orange counties.
Urban and small stream flooding has been a problem, but amounts of
2-3 inches in an hour with locally higher totals signaled the
potential for flash flooding. Some significant road/vehicular problems
have already occurred especially in the typically poor drainage
locations, but life/property remains in jeopardy until the
boundary rains itself out. The trend is for a gradual decreasing
in overall rain rates by 02-03z but not before another 1-2 inches
falls is spots.
The boundary should advance slowly northward through the overnight
as weak high pressure noses into the area from the east. A more
persistent onshore flow is expected near the coast as the atlc ridge
builds back in. This should keep min temps in the mid 70s at the
coast, otherwise temps bottom out in the low 70s. Will keep a
slight chance for showers overnight all locations.
Sun-Mon...(from previous) Zonal jet over central/eastern Canada
will drag an H100- H70 blocking ridge into the NW Atlc on Sunday.
This will allow the large H100-H70 cutoff low currently dominating
the WX pattern over the SE CONUS to lift north into the Great
Lakes region. There it will gradually become absorbed by the
northern stream by midday Monday. As the low lifts north, the Atlc
ridge axis over south FL will build north into the
panhandle...allowing mean winds through the H100-H70 lyr to shift
from E/SE on Sun to due E on Mon.
Source region has sufficient moisture to maintain at least sct PoPs
to start the week...PWat values increasing to 1.75"-2.00" by 18Z
Sun. PoPs 40-50pct on Sun as SE winds thru the H85-H70 lyr and
southerly winds abv H70 will tend to focus convection alng the spine
of the peninsula...while mid/upr lvl dynamic support will be
enhanced by the H85-H50 trof extending from the cutoff low into the
Deep South. PoPs decreasing to 40-50pct on Mon as a stronger erly
wind component thru the H100-H70 will tend to focus diurnal precip
over the west half of the peninsula...while dynamic support will be
waning as the cutoff low lifts north and dampens out. No change in
airmass...temps will be within a deg or two of recent readings with
maxes in the U80s/L90s...mins L/M70s.
Convective potential will be enhanced by relatively cool/unstable
mid lvl air...H70 temps btwn 8C-9C and H50 temps btwn -8C/-9C will
yield lapse rates of 6.5-7.0C/km thru the lyr.
&&
.AVIATION...VCTS thru 03-04Z for sites in vicinity of the I-4
corridor with occasional ceilings 025-035cb bkn/ovc. Otherwise,
improving conditions to VFR overnight but with isolated showers
lingering near inland sites thru 06z and near coastal sites 06-12z
due to marine showers.
&&
.MARINE...
Rest of Tonight...a convective boundary stretches southwest and
inland across Central Florida in vicinity of New Smyrna Beach.
Isolated showers will therefore remain over the Volusia County
coastal waters thru midnight, but additional isolated showers will
later develop elsewhere during the overnight. Prevailing winds
will be east to southeast at 5 to 10 knots with seas 3 feet
nearshore and up to 4 feet well offshore.
Sun-Mon...(from previous) Bermuda Ridge axis over the south FL
Peninsula will lift into the panhandle on Sun, then will steadily
erode as it is squeezed by a short wave trof over the ern seaboard
and by Hurricane Matthew`s approach from the south. A light to
gentle easterly breeze will prevail thru sunset Mon, freshening to
a gentle to moderate easterly breeze Mon night. The prevailing
easterly component will push a small swell into the lcl Atlc
waters that will enhance local wave heights. Seas 3-4ft thru Mon
evng, building to 4-5ft by daybreak Tue.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 72 87 73 86 / 20 40 20 40
MCO 73 88 74 87 / 20 50 20 50
MLB 74 88 75 87 / 20 40 20 40
VRB 72 88 75 88 / 20 40 20 40
LEE 71 89 72 87 / 20 50 20 50
SFB 73 89 73 87 / 20 50 20 50
ORL 74 88 74 88 / 20 50 20 50
FPR 73 88 73 88 / 20 40 20 40
&&
.MLB Watches/Warnings/Advisories...
FL...None.
AM...None.
&&
$$
SHORT TERM...DS
DSS/WARNINGS....AC
Area Forecast Discussion
National Weather Service Marquette MI
726 PM EDT Sat Oct 1 2016
.SHORT TERM...(This evening through Sunday)
Issued at 420 PM EDT SAT OCT 1 2016
WV imagery and RAP analysis indicated a mid/upper level low over
northeast Indiana and a ridge from the nrn plains to north of Lake
Superior. Radars indicated weak shortwave spokes to the north of the
low that supported bands of showers. At the surface, light northeast
winds prevailed between a ridge over nrn Ontario and low pres over
the s end of Lake Michigan.
Tonight, radar trends and short range models suggest that the area
of forcing to the southeast and 305k-310k isentropic lift will expand
back to the nw into the se half of the cwa during the evening.
However, enough dry air remains below 750 mb to limit the westward
extent of the pcpn. The clouds over the west may be thin enough for
radiational cooling and patchy fog. Otherwise, thicker mid clouds
will keep min temps from the mid 40s to the lower 50s central and
east.
Sunday, the mid level low will finally slide far enough off to the
east to the ern Great Lakes so that the pcpn will end and for skies
to gradually clear across the west half. However, there may be
some lingering light showers or sprinkles over the far east and south
early. With increasing sunshine, temps will remain above normal
with highs in the mid to upper 60s.
.LONG TERM...(Sunday night through Saturday)
Issued at 315 PM EDT SAT OCT 1 2016
No precip expected Sun night into Tue as high pressure ridging is in
control. Could see fog Sun night as ridge is overhead, then again
Mon night (especially over the southeastern CWA) as SE flow
increase.
Next chance of rain is late Tue night through Wed evening as a
shortwave and cold front move through. Not guaranteed as the
system will be pretty volatile.
Quite a lot of uncertainty after Wed as models show a series of
potent system, but are not in agreement on timing/strength/track.
Given this uncertainty, just stuck with blends and allocated time to
fixing some AWIPS issues.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 726 PM EDT SAT OCT 1 2016
A somewhat tricky forecast at KIWD tonight as there remains a
potential for fog development to produce MVFR/IFR visibilities along
with possible IFR ceilings. This will depend much upon how far west
and how long mid level cloud cover extends into the KIWD area. At
the present expect best chances for fog development to occur after
9Z with thinning of sky cover but have used tempo group to indicate
potential for fog prior to then. KSAW to deal with shower activity
through a good portion of the night and will also see cigs drop into
the MVFR range. Conditions at KSAW and KIWD to improve to VFR during
the late morning hours as a ridge builds into the area from the
west. KCMX to stay VFR through the forecast.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 420 PM EDT SAT OCT 1 2016
A weak pressure gradient across Lake Superior through Mon will keep
east to northeast winds at 20 kts or less. Southeast winds increase
over 20 kts Tue into Wed ahead of front moving out the Northern
Plains. The strongest winds will occur over north central and
eastern Lk Superior. Behind the front on Thu, west winds may gust
to near 25 kts.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Titus
AVIATION...RJT
MARINE...JLB
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php
Area Forecast Discussion
National Weather Service Wakefield VA
520 AM EDT Sun Oct 2 2016
.SYNOPSIS...
Low pressure moves north of the region today with its associated
frontal boundary moving off the coast this afternoon. A weak cold
front drops through the area tonight. High pressure builds north
of the area Monday into Tuesday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Latest MSAS showing the frontal boundary nearing the coast with
sct convection offshore. Weak low pressure is currently riding NE
across ern NC with the latest data supporting this activity
sliding NE across NERN NC and SERN VA next several hours. Thus,
updated the grids/zones to increase pops across those areas along
with adding slght chc tstms over NERN NE. Fog becoming sporatic
in nature but kept areas of fog in grids for now.
TSCTNS show abundant low and mid level moisture across the region
this morning with most areas now socked in with an ovc ST layer.
A blend of CONSshort and HRRR were loaded for the VSBY/SKY grids
thru 18Z with not much in the way of sunshine expected this
morning. Lowered temps a bit based on more clouds and less sun.
Highs 75-80 except lwr 80s across NE NC where the most sun is
anticipated.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
A secondary boundary pushes across the region tonight. This comes
through dry as any available moisture gets pushed offshore by 00Z.
Winds shift to more of a WNW direction allowing a somewhat cooler
airmass to filter across the fa. Mstly clr to pt cldy. Lows in the
mid 50s-lwr 60s.
High pressure builds into the area Mon thru Tues with the low-level
flow gradually becoming ne. Highs Mon in the upr 70s to near 80.
Lows Mon nite mid 50s-lwr 60s. Highs Tues mid-upr 70s.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
The mid week surface progs show a strong surface high over Maine
with ridging south into the Gulf Coast States. This high will
retreat to the northeast as a cold front approaches from the west
toward the end of the week. There will be 20 to 40 percent chance
for showers through the period especially across eastern portions
of the area...with the highest chances occurring on Friday.
Hurricane Matthew is expected to be nearly stalled over the
Bahamas around mid week and waiting for marching orders. The most
likely course at this time would be to the north or northeast but
uncertainty remains. Stay up to date on the latest forecast
information through the National Hurricane Center.
High temperatures are forecast to range from the lower 70s in the
Piedmont to the upper 70s in the southeast. Lows are expected to
range from the upper 50s to lower 60s well inland to the mid and
upper 60s in the southeast.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
Digital aviation grids will show a combo of CONSshort/HRR/ADJMAV
to account for the lower CIGS/VSBYS early this morning. Upshot
will be IFR CIGS/VSBYS at RIC/SBY/PHF. VRBL but mainly VFR east
of a frontal bounday at both ORF/ECG. A few shwrs may track north
along this boundary thru 18Z but timing difficult attm as no pcpn
is currently near any airfield. Latest high res data continues to
favor low clouds through the morning at inland sites with CIGS
BCMG mainly VFR by or shortly after 18Z.
OUTLOOK...Next chance for showers mainly toward the coast Wednesday
and Thursday.
&&
.MARINE...
Latest sfc analysis shows weak areas of low pressure over the
Great Lakes and off the New England coast. These lows will track
east today before high pressure builds in from the north through
midweek. Winds will be aob 10 kt and variable at times through
tonight, with north flow Mon transitioning to northeast Tue
through the end of the week. Expect winds/waves/seas to slowly
increase through the period with the high locked in place off the
New England coast and as Hurricane Matthew starts to move
northward off the SE coast. Expect at least sca conditions to
commence by Tue, continuing through the end of the week, with
other headlines also possible depending on the track of Matthew.
&&
.HYDROLOGY...
River flooding continues across the primary rivers of the Lower
MD Eastern Shore due to recent heavy rainfall, mainly the Pocomoke
and especially at Snow Hill. This flooding will likely continue
through Sunday based on latest levels and EM reports. See the
latest flood statements (FLWAKQ/FLSAKQ) for more details.
&&
.TIDES/COASTAL FLOODING...
Update (509 PM EDT)...
Coastal flood advisories have been extended for the following
areas: 1. MD Lower Eastern Shore (Ches Bay areas) 2. Northern Neck
Fresh water runoff due to excessive rainfall averaging 8 to 9
inches across the MD Lower Eastern Shore will keep tidal anomalies
elevated during the next one or two high tide cycles (early Sunday
morning and possibly early Sunday evening). Therefore, the coastal
flood advisory for this are has been extended through 700 AM. For
the Nrn Neck, Lewisetta just touched 3.5ft early this aftn and is
expected to crest around 3.2ft late tonight. A coastal flood
advisory for areas along the Potomac and wrn Ches Bay of the Nrn
Neck has been extended through 600 AM.
Otherwise, tidal anomalies will continue to decrease incrementally
by a few tenths of a foot with each passing high tide cycle
through early in the week. After which, a resurgence of persistent
and strong onshore/NE winds could exacerbate coastal flooding
concerns again by mid week (possibly beginning Tue night with the
initial surge in winds).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Coastal Flood Advisory until 7 AM EDT this morning for
MDZ021>023.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...MPR
MARINE...MAS
HYDROLOGY...
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Bismarck ND
344 AM CDT Sun Oct 2 2016
.SHORT TERM...(Today and tonight)
Issued at 344 AM CDT Sun Oct 2 2016
Another warm day is expected today, and in most areas it will be
dry, as well.
Early this morning, showers and weak thunderstorms are approaching
western ND in association with a weak, northeastward-moving short-
wave trough. This activity has been moving a bit faster than HRRR
and other convection-allowing model guidance has suggested, but
simple extrapolation suggests it will continue to move across the
western and especially northwest corner of the state through the
mid-morning hours. By afternoon, another, weaker vorticity maximum
embedded in southwest flow aloft is forecast to move from western
into north central ND, but we downplayed the chance of convection
with that wave since overall forcing is weak, and more importantly
both NAM and GFS forecast soundings suggest a notable mid-level
capping inversion will yield considerable MLCIN across the area
this afternoon and evening.
Highs today, based on the multi-model consensus but then weighted
toward the warmer side of the guidance envelope in the south where
we expect more sunshine, are forecast to mainly be in the 70s F. A
few 80 F readings are again possible in the south given mixing to
about 850 mb.
It will be mild tonight, and weak height falls will begin aloft.
However, the lack of a stronger low-level jet suggests the
probability of convection is rather low before daybreak Monday.
.LONG TERM...(Monday through Saturday)
Issued at 344 AM CDT Sun Oct 2 2016
Potential impacts in the long term forecast period include strong
southerly winds Monday in southern ND, the risk of strong to
isolated severe thunderstorms west and perhaps south central from
Monday afternoon through Monday evening, and a potential freeze in
many areas by Thursday night/Friday morning.
Synoptically, the 00 UTC global models were very closely clustered
in their depiction of a deep 500-mb low ejecting from the northern
Great Basin Monday morning, to near Billings by Monday evening. As
the cyclone occludes, it is then forecast to only slowly move into
southeastern Saskatchewan by 12 UTC Wednesday. The last 24 hours
of model cycles have strongly favored a stacked low that moves to
the west of the ND/MT state line, keeping western and central ND
in the dry conveyor belt of the system behind a Pacific cold front
forecast to cross the area Monday night. In fact, not one member
of the 00 UTC GFS ensemble even scraped western ND with the 500-mb
low. The 00 UTC ECMWF is a bit further east, and does suggest some
deformation-induced precipitation could impact extreme northwest
ND Tuesday night and Wednesday, but that solution is admittedly a
bit of an outlier. Suffice to say then that this forecast release
once again reduced the chance of precipitation this week, beyond
Monday night anyway, when showers and thunderstorms are likely in
the pre-frontal zone with significant height falls aloft.
On Monday, as the surface low deepens to around 990 mb or perhaps
a bit less in eastern MT, low-level southerly flow will intensify
over southwest and especially south central ND. Forecast sounding
profiles from both the 00 UTC NAM and GFS in places like Bismarck
and Jamestown suggest mean mixed-layer winds near 30 kt with peak
speeds around 40 kt Monday afternoon when mass flow adjustments
will likely be maximized. Moreover, NAEFS guidance supports 850-mb
wind speeds in the 97th+ percentile over south central ND, and so
we raised winds over the multi-model consensus (closer to gridded
GFS MOS output), and it`s possible a wind advisory may be needed
over parts of southern ND and the James River valley.
Guidance suggests showers and thunderstorms may occur throughout
the day Monday, especially in the west and north, in response to
low- and mid-level theta-E advection. However, more robust and
surface-based thunderstorm development is possible by late day
from eastern MT into northwest SD and eventually western ND, when
the air mass may be characterized by MLCAPE of 500-1200 J/kg with
surface dewpoints in the middle to upper 50s F (if enough warming
occurs in the boundary layer). Given 0-6-km bulk wind differences
of 40-50 kt, organized and rotating storms are possible and that
CAPE-shear setting supports a marginal risk of severe weather. A
cluster or linear mode is likely to the storms with wind profiles
in forecast soundings showing a veer-back-veer signature aloft.
Given that and marginal boundary layer moisture, we are not that
concerned about tornado potential despite near-surface veering of
the winds and 0-1-km bulk wind shear values near 20 kt. Hail and
wind of the marginally-severe variety is likely to be the focus.
We expect a wave of showers and storms to then shift northeast
across the area Monday night ahead of the cold frontal passage.
That`s the most likely time frame for wetting rains with this
system. The northern and eastward extent of any strong/severe
storm risk is dependent on the width of the instability axis,
which is somewhat uncertain.
Thereafter, cold air advection will occur through the week, and
guidance supports sub-zero 850-mb temperatures Wednesday night
through Friday. MOS-based guidance still strongly supports the
potential for a rather widespread and potentially hard freeze
Thursday night/Friday morning, especially in western ND in the
closest proximity to a surface ridge axis. Not one of the 00 UTC
GFS ensemble MOS members keeps temperatures above 32 F Thursday
night/Friday morning at Williston, Minot, Dickinson, Hettinger,
or Bismarck.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 344 AM CDT Sun Oct 2 2016
Scattered rain showers and possibly a VCTS possible early Sunday
morning over northwestern North Dakota. Added a VCSH for KISN for
now and will monitor and amend as needed. Additional showers
and/or storm possible northwest and north central Sunday afternoon
and evening, for now left weather mention nil. Overall VFR
conditions will prevail.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...NH
Area Forecast Discussion
National Weather Service Buffalo NY
438 AM EDT SUN OCT 2 2016
.SYNOPSIS...
An upper level low will slowly move into our region today, and
then exit into New England and weaken on Monday. This will keep
the weather unsettled through Monday with periods of rain showers.
High pressure will then bring a return to dry and warm weather
Tuesday through Thursday.
&&
.NEAR TERM /THROUGH TONIGHT/...
Steady showers have exited the region with just a few scattered
showers lingering across the Eastern Lake Ontario region early this
morning. A mid level dry slot will rotate around an upper level low
which is across Eastern Michigan. This will keep Western New York
mainly rain-free through daybreak.
Around daybreak large scale ascent and deeper moisture will
spread northeast across Lake Erie in advance of the mid/upper level
low. The increasing DPVA ahead of the system will bring some showers
into the Niagara Frontier this morning, but mesoscale guidance shows
the heaviest showers are likely to develop along a convergence
boundary just ahead of the surface low. This will combine with DPVA,
resulting in an area of rain which will enter Western New York late
this morning. This area of rain will continue to expand and spread
east across the Genesee Valley and western Finger Lakes during the
afternoon, reaching Central NY by early evening.
Model consensus is in fairly good agreement in timing the
progression of this low, and the precipitation associated with it.
Also, with the more significant dynamic forcing expect precipiation
today to be more persistent than yesterday even though there will be
areas of dry weather outside of the cluster of showers which is
expected to develop.
SBCAPE will rise into the 500-800J/kg range from both daytime
heating over the land and also from lake instability, supporting a
few scattered thunderstorms. Steep low/mid level lapse rates and
low wetbulb zero heights suggest some of these storms may produce
small hail. Modest shear in the lowest 10k feet of the atmosphere
will prevent any severe weather, although a few of the storms may
also contain gusts winds and brief, heavy downpours.
In addition, the airmass grows cold enough to support a lake
response as well, with lake induced equilibrium levels rising to
around 20k feet off Lake Erie in the afternoon with the approach
of the upper level low and associated cold pool. This should
support a plume of lake enhanced rain showers across the Niagara
Frontier.
The stacked low will slowly move across the region from west to east
tonight, with steadier showers lingering across the Eastern Lake
Ontario region. In addition, cool air aloft will continue to support
some lake effect showers across the Western Southern Tier and
southeast of Lake Ontario.
Winds will shift to the northwest behind the departing low late
tonight. This may result in some fog, especially south and east of
Lake Ontario where there will be the most low level moisture.
Highs today will be in the 60s in most areas, but may top 70 east of
Rochester due to the later arrival of rain showers. Cooler air will
build in tonight, however cloud cover and low moisture should
limit radiational cooling with lows in the upper 40s to lower 50s.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Water Vapor imagery displays an upper level closed low over the
western end of Lake Erie this early morning, and by the start of
Monday morning this feature will become an open wave, centered over
New York State.
Moisture depth will be greatest Monday morning where cloudy skies
will produce a few lingering showers and drizzle, especially over
the Genesee Valley and points eastward into CNY. A northerly flow
behind the upper level low will maintain upslope light precipitation
over the hills of the Finger Lakes and Tug Hill region. As upper
level heights rise through the day, and moisture field begins to
wane we should see a diminishment in the precipitation, through
moisture trapped in the lower levels will maintain a deck of stratus
over the region. These clouds and 925 hPa temperatures of around
+12C will bring highs ranging through the 60s.
By Monday night and Tuesday the low level moisture will continue to
diminish, now that we are on the back side of the upper level low.
We should be precipitation free as surface high pressure returns its
influence over the region from Northern New England, though moisture
remaining stubborn in the lower levels will likely linger clouds
through the night Monday, and possibly into Tuesday before daytime
mixing brings some sunshine back to the region.
Warm air advection on Tuesday, along with a diminishing low level
moisture field, and a now light easterly flow will allow for
temperatures to be a bit warmer, with highs now ranging from the
upper 60s into the lower 70s. Tuesday night we will see a return to
mostly clear skies, with over night lows in the 50s, with locations
within the interior So. Tier, and Eastern Lk Ont region dropping
into the upper 40s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A strong sub tropical ridge centered off the Mid Atlantic coast will
control much of our weather during this period. The heart of its
associated surface high pressure will initially be anchored near
Nova Scotia and will extend back across the Lower Great Lakes...but
as we head into the weekend...a vigorous shortwave crossing the
Upper Mississippi Valley will help to dislodge the expansive fair
weather feature.
The result of this will be fairly nice weather Wednesday through
Friday across our forecast area with abundant sunshine and
temperatures that will average well above normal. Max temps will
generally be in the 70s... which is about 10 deg F above early
October norms.
Things will start to get interesting as we push into the weekend...
particularly along the East Coast where Hurricane Matthew will be
chugging its way to the north. The good news for our forecast area
is that none of the new 00Z Global guidance packages are suggesting
a DIRECT impact from the tropical system for our region. The bad
news...if you want to call it that...is that a fairly vigorous
shortwave moving across the Upper Great Lakes will push a slow
moving cold front across our region. It is fairly reasonable to
assume that at least some of the tropical moisture from Matthew will
be entrained into the airmass ahead of the cold front. This will
enhance the potential for some moderate to heavy showers with the
frontal passages...so we will have to keep an eye on this. Best
timing for any showers and possible thunderstorms would be
late Friday night and into Saturday.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
There will be lots of low moisture nearby the region with dense
fog just upstream across Southern Ontario. This should largely
remain to the west with HRRR guidance suggesting it may clip IAG
early this morning. Meanwhile, IFR CIGS are likely to continue at
JHW until mid-morning.
An upper level low will approach this morning, and is likely to
bring a period of steady rain to all TAF sites as it slowly moves
from west to east. Cooler air aloft (and upstream obs) suggest the
potential for some embedded thunderstorms and locally heavier
rainfall with mainly MVFR but localized IFR conditions today.
This will linger into this evening further to the east at ART.
Conditions should improve some behind the low, but a southwesterly
flow combined with cool air aloft may result in some lake effect
showers and clouds with localized MVFR conditions at BUF this
evening.
Winds will shift to the northwest behind the low late tonight.
This may result in IFR or lower conditions south of Lake Ontario
with BUFKIT showing low level moisture pooling with the wind shift.
Outlook...
Monday...Areas of MVFR with scattered showers.
Tuesday through Thursday...Mainly VFR.
&&
.MARINE...
A diffuse surface low will slowly move across the lakes today,
following the west to east track of its supporting upper level
low. Winds will become southwest increase this afternoon on Lake
Erie and this evening on Lake Ontario. Winds should should remain
just below Small Craft Advisory criteria. Winds will diminish on
Monday as the surface low drifts towards New England and
dissipates. High pressure will then bring light winds Tuesday
through Thursday.
Conditions will become favorable for waterspouts through Monday
morning on Lakes Erie and Ontario as the upper level low
approaches and air cools aloft. The new run of the Szilagyi
waterspout forecast suggests a good chance of waterspouts today
and tonight on Lake Erie, and this afternoon and evening for Lake
Ontario.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...RSH/THOMAS
AVIATION...APFFEL
MARINE...APFFEL
Area Forecast Discussion
National Weather Service State College PA
435 AM EDT Sun Oct 2 2016
.SYNOPSIS...
A cut off upper low will drift east across the southern peninsula
of Ontario today...keeping a deep-moist southerly flow over the
region. A ridge of high pressure will build east into
Pennsylvania behind this system early next week, and will likely
remain over the area through the middle, and perhaps end of the
work week bringing mainly dry and slightly milder conditions
across Central Pennsylvania.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Early morning infrared satellite imagery and radar mosaic loop
shows widespread cloud cover with generally just some patchy
light drizzle and areas of 1/2-1 1/2sm fog across the higher
terrain (mainly AOA 1800 ft msl).
07Z HRRR indicates that the rest of the morning and early
afternoon hours will be cloudy and dry...with the exception of
the northwest mountains where a few showers are possible through
16Z.
Just some patchy drizzle e again be steady and nearly uniform
in the mid to upper 50s. Some locations across the higher terrain
will see temps dip into the lower 50s for several of the mid
morning hours.
Winds will be light and mainly from the south during the early to mid
morning hours.
Morning low clouds are likely to give way to brightening skies
by this afternoon, as the low level flow veers from the sse to
sw.
However, still expect to see plenty of clouds thanks to cooling
temps aloft. As the upper low and associated 700-500 mb thermal
trough tracks east into the area this afternoon, there will be an
increasing chc of showers across the Alleghenies between 16-19Z,
and across the rest of central Pa during the late afternoon and
early evening hours 20Z-00Z Monday. 02Z/00Z NAM and 02/04Z HRRR
paints a likelihood of showers across the central and NW mtns this
afternoon (with even a slight chance of a thunderstorm as MU capes
peak at 400-500 j/kg). Much of the Susq Valley and far Scent PA
will stay dry through about 21Z...before a few scattered showers
drift into that area toward dusk.
Temps will rebound a bit above Saturday`s levels, reaching the
mid 60s over the NW and ranging to the lower 70s over the SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Partial clearing is expected tonight across the south-central
cent mtns and Lower Susq Valley while plenty of clouds and a few
isolated to scattered showers drift across the region north of
Interstate 80.
lows tonight will vary from near 50F over the high terrain of the
north and west to the mid and upper 50s in the SE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Fair weather will follow with a slight chance for showers across
the north early next week.
Surface high pushing the cooler air our way slides off the New
England coast midweek, and creates an easterly low level flow once
again with a long fetch of moisture aimed at southern PA.
This should create plenty of clouds around, along with at least a
chance for light showers/areas of drizzle across southern half of
the CWA through midweek.
Latest on Hurricane Matthew in the 00z runs - Tremendous
differences have developed between the ominous GFS and the much
more benign forecast by the latest EC for the U.S. main-land.
The 00Z GFS brings a potent Matthew across the Western Bahamas
then has it paralleling the SE U.S. and Carolina coast late in
the week...before projecting it to get captured by a deepening
upper trough and accelerating north into Long Island next Sat/Sat
night. GEFS has roughly the same track, but as expected becomes
more diffuse through time with the location and intensity of the
storm`s center just off the East Coast.
The 30/12z operational ECMWF parked the storm over or just to the
north of the Bahamas for a prolonged period during the middle to
latter part of the upcoming week, which was a low confidence
solution.
The latest 01/00Z run of the EC now carries the hurricane well to
the northeast of the Bahamas Friday and on a steady course to the
Northeast toward Bermuda by the middle of next weekend. With such
drastic differences between the GFS/GEFS and the EC 5-7 days out,
we`ll continue to play the middle of the road and note just
scattered showers with the passage of a more definitive northern
stream shortwave and sfc cold front late next week or early next
weekend.
Temperatures will be slightly below normal through the latter half
of 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 SUNDAY THROUGH THURSDAY/...
Widespread IFR ceilings this morning with some drizzle and fog.
Gradual improvement to MVFR/VFR is projected by later this
afternoon. Scattered to numerous showers developing 15-18z across
the western 1/2 airspace moving east into ZNY sector after 20z.
Expect decreasing -SHRA coverage 00-03z with some clearing into
early Monday morning. Any clearing would likely result in fog
formation during the predawn hours and may address this with the
02/12z scheduled TAF issuance.
Outlook...
Mon...AM low clouds/fog, becoming VFR.
Tue...AM visibility reductions possible in patchy fog, then VFR.
Wed-Thu...Mainly VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Lambert/Gartner
AVIATION...Steinbugl
Area Forecast Discussion
National Weather Service Duluth MN
427 AM CDT SUN OCT 2 2016
.SHORT TERM...(Today through Monday)
Issued at 427 AM CDT Sun Oct 2 2016
The main challenges with this forecast involves the evolution of
clouds and low stratus this morning, the degree of clearing
tonight, and associated min temperatures.
Persistent cut-off upper low was centered over southern Lower
Michigan early this morning with a high amplitude ridge farther
west over the Central and Northern Plains and Upper Midwest. A
compact vort max was observed on water vapor imagery over
northwest Ontario, which was supporting an area of mid-level
stratus over north-central and western Minnesota. Weak northeast
winds off Lake Superior had advected fog and low stratus over
portions of northwest Wisconsin and adjacent areas of east-
central Minnesota once again. Several locations in the Twin Ports
and northwest Wisconsin have reported fog overnight with
visibilities less than 1/4 mile at times.
Expect fog and low stratus to lift and mix out through mid-
morning with increasing wind speeds and gradually warming
temperatures. Liked the slower warm up of the HRRR solutions this
morning, so trended hourly temps over Wisconsin toward HRRR blend.
Other lingering question for today is how long the clouds will
linger over northern Minnesota. The presence of the compact vort
max and available moisture seems to suggest skies will remain
partly cloudy to partly sunny into the afternoon. However,
mesoscale models have shown a consistent trend of dissipating the
cloud cover over northern Minnesota by late morning/early
afternoon. Trended toward clearing skies, as with the previous
forecast. As a result, we are still holding onto max temps this
afternoon near 70 in northern Minnesota with upper 60s in
northwest Wisconsin. Should the cloud cover be slower to
dissipate, forecast highs would be too warm.
The next concern is the redevelopment of fog and low stratus over
Wisconsin tonight and min temperatures. Winds will be less
favorable for advecting a marine layer inland overnight, so kept
fog/low stratus to portions of northwest Wisconsin adjacent to the
lake. Elsewhere, continued the clearing trend from previous
forecasts. Model consensus also indicates mainly clear to partly
cloudy skies overnight. With relatively light winds and mostly
clear skies anticipated, nudged min temps a bit cooler over
northwest Wisconsin and portions of the Arrowhead. This matches up
well with some of the high-resolution guidance and collaboration
with neighbors. Look for temps overnight around 40 in north-
central Wisconsin and far northeast Minnesota, and near 50 degrees
in my western zones.
The resident cut-off low will be well east of the Northland by
Monday morning while the next significant upper-level trough
pushes into the Rockies. Southerly breezes will develop through
the day with the approaching low and mainly sunny to partly cloudy
skies should be the norm. The southerly winds should result in
cooler temperatures over northeast Minnesota thanks to the
influence of Lake Superior. Look for highs in the upper 50s over
southern Lake and southern Cook Counties to the upper 60s to low
70s elsewhere.
.LONG TERM...(Monday night through Saturday)
Issued at 427 AM CDT Sun Oct 2 2016
A period of heavy rainfall expected mid-week followed by some of
the coldest temperatures so far this fall late-week. Another
chance for precipitation late-week, with some scenarios leading to
the first snowflakes of the season for parts of the Northland.
Temperatures gradually warm through next weekend but remain a few
degrees below normal.
On the synoptic scale an upper low gradually moving across the
Great Basin and northern Rockies will be the feature of interest
as a resulting surface low develops over the northern High Plains
into southern Saskatchewan and southern Manitoba mid-week. The
deepening low combined with a longwave mid-level ridge over New
England will result in strong southerly flow through much of the
column Monday through Wednesday ahead of a cold front, bringing
warm moist air to the upper Midwest. Precipitable water values
will rise to 1.20 to 1.45" - not especially notable if this were
mid-summer, but for early October these values are approaching the
90% percentile levels compared to climatology. As the surface cold
front approaches from the west late Tuesday and crosses the
Northland Tuesday night through Wednesday, rain is expected along
and ahead of the front. At this point guidance is in fairly good
agreement with the bulk of this precipitation occurring late
Tuesday night when a very strong low level jet (on the order of
50-60+ knots) will result in a period of heavy rainfall with
occasional thunder across parts of northern Minnesota. A narrow
north-south oriented corridor of 2"+ will be possible, and WPC has
included much of Minnesota within a Marginal risk for flash flood
potential, with a Slight risk for parts of central Minnesota near
the Brainerd Lakes and Lake Mille Lacs areas, which we agree with.
Temperatures ahead of the front will be very warm Tuesday with
highs in the mid 60s to low 70s - 10 to 15 degrees above normal
(though far from the record of 83 at Duluth). Low temperatures on
the other hand will be VERY warm in the 50s Monday night, mid 50s
to near 60 Tuesday night - near record values compared to the
average low in the upper 30s.
The cold front moves from west to east across the Northland
Wednesday leading to cooler temperatures, with rainfall possibly
lingering through the day. Another round of precipitation is
possible sometime Thursday into Friday as a mid-level shortwave
trough quickly lifts across the central Great Plains into the
upper Midwest (GFS a slower solution, ECMWF a bit faster). In
either scenario the cold front will be stalled across western Lake
Superior, and behind the front in the Minnesota Arrowhead a mix of
rain and snow is possible Thursday or Friday night due to near-
freezing temps at the surface and aloft. Should the precipitation
fall during the day temperatures would be too warm to support
snow, but any overnight precipitation across the Arrowhead either
night (more likely Fri night) could lead to some snow. Little to
no accumulation expected at this time. Temperatures still on the
mild side Wednesday with highs int he low to mid 60s (highs
possibly occurring early in the day with temps falling through the
afternoon depending on the frontal passage timing). Cooler behind
the front -lows in the 40s Wednesday night, highs in the 50s
Thursday then upper 30s to low 40s Thursday night. The coolest air
arrives Friday into Saturday with highs in the mid 40s and lows
Friday night in the mid to upper 30s - a few locations falling to
near freezing.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1228 AM CDT Sun Oct 2 2016
Main focus in the TAFs is the marine stratus layer advecting into
the region along with radiation fog. Expect the marine stratus
layer to impact HYR bringing LIFR ceilings and MVFR or lower
visibilities. The RAP/NAM/HRRR/DLHWRF have had the best handle on
the current situation, so have leaned on this guidance in the
latest TAF set. DLH still remains along the periphery of the
marine layer, but opted to go with the latest DLHWRF/RAP which
keep DLH out of the marine stratus. Still will need to closely
monitor as KCOQ is within this layer in VLIFR visibility/ceilings.
KHIB/KBRD will radiation fog due to light winds and relatively
clear skies.
Will see the marine stratus and radiation fog dissipate around
14Z- 15Z Sunday morning. Expect a return to VFR conditions with
winds less than 10 kts as high pressure builds over the region.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 67 47 65 52 / 0 0 0 0
INL 71 49 70 53 / 0 0 0 0
BRD 69 51 70 57 / 0 0 0 10
HYR 68 45 68 53 / 0 0 0 0
ASX 66 44 67 51 / 0 0 0 0
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...Huyck
LONG TERM...JJM
AVIATION...WL
Area Forecast Discussion
National Weather Service Lincoln IL
327 AM CDT SUN OCT 2 2016
.SHORT TERM...(Today and tonight)
ISSUED AT 324 AM CDT Sun Oct 2 2016
The initial concern is where dense fog will form early this morning.
Varying cloud cover is adding difficulty to that determination. Any
areas with a period of clearing have seen visibility drop to less
than a mile, while visibility in cloudy areas remains 5SM or better.
A dense fog advisory may be needed along and south of I-72 per the
HRRR guidance, but will hold off due to uncertainties in cloud cover
progression. Satellite loops confirm there are plenty of upstream
clouds to rotate south over our CWA, so that could preclude
widespread dense fog even in our south. Will monitor closely for
possible need for an advisory.
An elongated surface low from north to south in western
Indiana will linger nearby long enough today to keep plenty of cloud
cover in place across central and southeast Illinois. HRRR and RAP
output are pointing toward spotty showers or sprinkles possible in
most areas this afternoon, but the overall consensus of rain chances,
including the GFS/NAM/ECMWF models, seems to be along a trailing
lobe of low pressure across our southern forecast area. We kept
slight chance /20%/ PoPs going this afternoon south of Springfield
to Effingham to Robinson. We may see spotty sprinkles north of
there, but we left a dry forecast in place for today.
High surface pressure will progress into Illinois tonight, with dry
mid level air pushing into the area. However, time-height RH
analysis confirms that low level moisture content will remain high,
allowing for clouds to develop in any clearing areas that possibly
develop later this afternoon. Will continue to mostly cloudy skies
even Sunday night, which will limit the diurnal temperature range,
as lows bottom out in the middle 50s. Fog will likely form again
tonight, with areas of dense fog in areas that clear out for any
period of time.
&&
.LONG TERM...(Monday through Saturday)
ISSUED AT 324 AM CDT Sun Oct 2 2016
Large 564 dm 500 mb low pressure over southeast lower Michigan will
lift out into southern New England by sunset Monday, while upper
level ridge shifts east over IL and central Great Lakes. Weak
surface high pressure ridge of 1020 mb from MN south into AR will
drift east over IL and ohio valley tonight and into New England and
eastern Canada on Monday. Areas of fog and locally dense early
Monday morning will lift during mid Monday morning with skies
becoming partly sunny with lingering scattered to even broken
cumulus clouds. Seasonable highs Monday in the low to mid 70s.
Fair skies Monday night with lows of 53-58F, coolest near the
Indiana border where winds will be lighter closer to high pressure.
Patchy fog could develop over eastern IL later Monday night.
Cutoff upper level low pressure off the WA/OR coast will track into
eastern MT by sunrise Tue and eject northeast into southern Manitoba
on Wed, while upper level ridge shifts east to the eastern seaboard.
1030 mb high pressure over New England Tue/Tue night to ridge WSW
into the ohio valley and keep CWA dry and milder. Highs Tue in the
upper 70s to near 80F with southeast winds. Lows Tue night mostly in
the lower 60s with a few upper 50s from Champaign and Paris
northeast.
00Z models show a piece of energy ejecting northeast across the
upper Midwest on Wed and bringing good chances of showers and
thunderstorms to the IL river valley Wed and Wed night while just
slight chances over southeast IL later Wed afternoon into Wed night.
Warm highs Wed mostly in the lower 80s, ranging from 78F by
Galesburg to 84F by Lawrenceville. Models have trended slower with
arrival of cold front on Fri instead of Thu like yesterdays runs.
Therefore warmed highs on Thu quite a bit, into the upper 70s and
lower 80s. Also have higher pops over nw CWA on Thu and lower pops
in southeast IL further from the front. Models show surface low
pressure near KS/OK border on Thu ejecting northeast into the
western Great Lakes by Fri morning and then pulling the cold front
east over IL on Friday. This will continue chances of showers and
isolated thunderstorms on Friday and Fri evening, then diminishing
or ending overnight Friday night. High Fri range from mid 60s nw of
IL river by Galesburg to mid 70s near the Wabash river valley.
Upper level trof swings east across IL friday night then followed by
cooler and drier weather next weekend behind the cold front and
upper level trof. Highs Sat in the low to mid 60s and highs Sunday
in the mid to upper 60s. Lows Friday night and Saturday night in the
mid to upper 40s, so back to fall weather.
Powerful Category 4 Hurricane Matthew packing winds of 150 mph was
located at latitude 13.8 North and longitude 73.9 West at 2 am EDT,
moving NNW at 6 mph. Hurricane Matthew is forecast by the National
Hurricane Center (NHC) to track northward to eastern Cuba and
western Hispaniola Monday night, and near the eastern Bahamas by
Wed night. Stay tuned to later forecasts from the National
Hurricane Center if you have travel plans to the the Caribbean or
the East Coast.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1050 PM CDT Sat Oct 1 2016
Little change from previous thinking with the main forecast
concern being the potential for dense fog with IFR to LIFR
cigs/vsby into the mid morning hours of Sunday. Fog already
starting to develop in parts of west central Illinois late this
evening and expect this trend to continue overnight. Any areas
that have or do experience and brief period of clear skies
overnight may see more widespread dense fog early Sunday morning.
Forecast soundings suggest a rather shallow layer of moisture so
it appears the fog/low vsbys and stratus should begin to improve
after 14z with scattered to broken cumulus developing by late
morning/early afternoon with cig bases in the 4000-5000 foot level
by afternoon. Winds once again will not be much of a factor with
light and variable winds tonight and a light northwest wind
expected on Sunday with speeds less than 10 kts.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
Area Forecast Discussion
National Weather Service Marquette MI
452 AM EDT Sun Oct 2 2016
.SHORT TERM...(Today and tonight)
Issued at 452 AM EDT SUN OCT 2 2016
Water vapor imagery and RAP analysis show a mid level low over the
Great Lakes region with the center near Detroit. NW fringe of the
deep layer forcing associated with this feature and the minor
shortwaves rotating around it is generating a few shra across
eastern Lake Superior and the east half of Upper MI early this
morning. Coverage has diminished from the evening hrs. The w has
remained dry, and once again low clouds and fog are plaguing the far
w around KIWD as nne flow across western Lake Superior transports
warmer/more humid lake modified air upslope into the cooler air over
the land.
Mid level low will drift e across the Lower Great Lakes today. As it
does so, heights will begin to rise with deep layer q-vector
divergence/subsidence spreading across the fcst area. Thus, expect
lingering isold/sct -shra over roughly the east half of the fcst
area to end by aftn. With back edge of the clouds associated with
the mid level low currently over western Upper MI, skies will become
mostly sunny over at least the w and central fcst area today. High
temps will be in the 60s, warmest over the w half under less cloud
cover.
Sfc high pres ridge will shift over the fcst area tonight, providing
a quiet night. While some lingering clouds over the e along with a
stronger ene wind just off the sfc should reduce the potential of
fog development in that area tonight, mostly clear skies and lighter
winds under ridge axis over the w and central will lead to some fog
development tonight as temps fall back blo the expected minimum dwpt
readings this aftn. Light wind fields suggest flow off the Great
Lakes probably won`t be a factor in fog development. If there is any
marine influence, it would occur over n central Upper MI into the
Keweenaw under 950mb winds veering from ne to e. Min temps may slip
just blo 40F over the interior w tonight under best radiational
cooling. Highest readings will be along Lake Superior where temps
should mostly stay aoa 50F.
.LONG TERM...(Monday through Saturday)
Issued at 412 AM EDT SUN OCT 2 2016
Although a sfc hi pres rdg axis under a slowly progressive upr rdg
wl bring dry wx to Upr MI on Mon thru Tue ngt, lo clds in the slowly
veering e to sly llvl flow may prevail early in the week, especially
after sunset on Mon. The next chc of showers wl arrive on Wed ahead
of an aprchg warm conveyor belt/cold fnt associated with a sfc lo
pres riding newd thru scentral Canada. There is good agreement among
the guidance the fnt wl pass on Wed ngt, but the timing of a wave of
lo pres tracking to the ne along the stalled fnt on Thu/Fri under
the sw flow aloft to the w of persistent well above normal hgts that
could result in some heavier rain is still in question. Cooler wx
and perhaps some lk effect rain showers wl arrive next weekend in
the nw flow ahead of Cndn hi pres bldg into Ontarior.
Mon thru Tue ngt...Upr MI wl be under the influence of a slowly
progressive upr rdg btwn a deep trof moving thru the Rockies into
the Plains and the disturbance responsible for the showers this mrng
that wl be quickly exiting thru the ne states on Mon. At the sfc, a
hi pres center over far NW Quebec on Mon wl extend a sfc rdg axis
into the Upr Lks, resulting in dry wx under the large scale
subsidence. But as the llvl flow veers more to the se during the day
as the sfc hi pres drifts to the e, some of the models show incrsg
llvl mstr advctn and the potential for some lo clds to spread into
the area, especially the scentral with upsloping off Lk MI. As the
sfc hi pres moves into the Cndn Maritimes on Tue, the llvl flow wl
veer further to the s and incrs under the tightening pres gradient
btwn the hi and falling mslp in the nrn Plains ahead of the upr trof
shifting to the e. Even though the mid lvl dry air/subsidence under
the upr rdg wl allow continued dry wx, this s wind wl enhance llvl
mstr advctn under sharpening subsidence invrn into the cwa. Fcst
sdngs sug a good deal of lo clds wl prevail Mon ngt thru Tue ngt
with this setup. There could be some dense fog on Mon ngt over
mainly the scentral. Best chc for some breaks in this lo cld cover
wl be over the downslope areas near Lk Sup. H85 temps are fcst to
rise fm arnd 9C on Mon to as hi as 12C on Tue over the w, where the
sly flow wl downslope. So expect abv normal temps to prevail. With
the lo clds and steady s winds, the min temps anomaly fm normal wl
be most sgnft.
Wed thru Fri...While the nrn portion of the wrn trof is fcst to make
progress to the ene and allow a fairly deep sfc lo pres to move fm
the nrn Plains into Hudson Bay, many of the medium range models
indicate the srn portion of the trof wl hang back over the srn
Rockies thru at least Thu. As the lo ahead of the nrn portion of the
trof shifts to the ne, it is fcst to drag a cold fnt acrs the Upr
Lks on Wed ngt. Since the more impressive dpva/hgt falls are fcst to
pass to the nw of Upr MI, pcpn ahead of the cold fropa that wl
arrive w-e on Wed may not be too heavy despite fcst pwat up to about
1.5 inches under the warm conveyor belt in advance of the fnt. But
since the srn portion of the trof wl hang back to the w of a
lingering upr rdg/well abv normal hgts over the se states and
maintain a sw flow alf over the Great Lks, the fnt should stall not
far fm Upr MI. Depending on how quickly the srn portion of the trof
lifts to the ne, a sfc lo pres wave ahead of the disturbance could
ride ne along the stalled fnt into the Upr Great Lks and drop some
heavier rain on Thu/Fri as hinted by the 00Z GFS/12Z ECMWF. While
there wl be some cooling in the wake of the cold fropa after Wed and
perhaps toward normal by Fri, above normal temps should persist thru
this time, especially on Wed ahead of the cold fropa. Quick look at
the 00Z ECMWF shows a farther w track for the sfc lo pres late in
the week, which would result in a longer period of above normal
temps and perhaps some TS.
Sat/Sun...As an upr trof deepens with caa btwn the departing sfc lo
pres wave and hi pres bldg into nw Ontario, h85 temps are progged to
fall as lo as -4 to -6C next weekend. The arrival of this cooler air
over the relatively warm lk waters should result in a lk induced
trof and pcpn in the dvlpg cyc nw flow. Not out of the question some
sn could mix in with the lk effect rain showers over the hier
terrain, but expected near sfc temps appear too warm to support a
fcst of this ptype attm.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 131 AM EDT SUN OCT 2 2016
LIFR conditions continue at KIWD this morning with low clouds and
fog. These restrictions should improve after sunrise with VFR
conditions returning there by 14Z. There is some concern that the low
clouds and fog will return to KIWD late in the forecast with ridging
building in but will leave mention of this out for now. Lingering
showers at KSAW to continue through much of the night but should see
any lower ceilings and the showers end by 12Z with VFR conditions
prevailing through the rest of the forecast. VFR conditions to
prevail at KCMX.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 452 AM EDT SUN OCT 2 2016
Under a weak pressure gradient across Lake Superior, winds will be
mostly under 15kt through Mon. Southeast winds will then increase
Tue/Wed as a cold front approaches. Strongest winds, up to 20-25kt,
will occur Wed over eastern Lake Superior. Cold front will pass
across Lake Superior Wed aftn/evening. W to SW winds up to 15-25kt
should occur on Thu, strongest btwn Isle Royale and the
Keweenaw Peninsula.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...KC
AVIATION...RJT
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Morristown TN
339 AM EDT SUN OCT 2 2016
.SHORT TERM (Today and Tonight)...
The upper level closed low continues to be the main synoptic feature
in the short-term forecast. Current water vapor and RAP upper air
analysis indicates that the center of this low is now in Southern
Michigan. A surface low exist directly under the upper level low
with broad surface high pressure in place across the Southeastern
U.S. Low level moisture remains elevated across SW VA and NE TN with
light winds across the area. Therefore, expect some areas of patchy
fog this morning. Expect any ongoing fog will dissipate shortly
after sunrise.
Dry conditions will continue today with upper level heights
increasing as the upper level closed low continues to lift slowly to
the northeast. A weak upper level shortwave trough will rotate
around the based of the closed low today moving across the Southern
Appalachians. PW values remain around 0.9-1.1 inches. These values
are around normal for early October. In addition, there will be no
surface boundary across the area. With this said, just expect an
increase in cloud cover but no precipitation. High temperatures will
be a couple of degrees warmer due to the higher heights aloft. Highs
will top out near normal ranging from low 70s to low 80s.
.LONG TERM Monday through Saturday)...
The extended period will begin with a quiet weather pattern as a
ridge of high pressure continues to build into the area. With the
high in control though at least Thursday...plan on generally dry
conditions with warming temperatures. Afternoon highs should reach
into the upper 70s and 80s by mid week across the Tennessee Valley.
Model consistency has been quite poor late in the period and
confidence remains low. The overall pattern shows a weakening
frontal boundary approaching the area from the west and a tropical
system moving along the east coast. The models are trending slower
with the approach of the front...and current model runs do not
bring it into the area until late Friday or into Saturday. The
tropical system also seems a bit slower with its track along the
coast...but models are fairly consistent with associated precip
staying east of our area. As a result...will keep precip chance low
Friday and Saturday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 80 59 82 59 / 0 0 10 10
Knoxville McGhee Tyson Airport, TN 78 56 80 57 / 0 0 10 10
Oak Ridge, TN 78 57 80 57 / 0 0 10 10
Tri Cities Airport, TN 75 53 78 55 / 0 0 10 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&
$$
MA/MJB
Area Forecast Discussion
National Weather Service Albany NY
1004 AM EDT SUN OCT 2 2016
.SYNOPSIS...
An upper level low will continue to bring mostly
cloudy and cool conditions with isolated to scattered shower today
into Monday. The upper low will move east of the region Monday
night. High pressure will bring fair and dry weather for Tuesday
into Wednesday with temperatures trending above normal.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 10 AM EDT...H2O vapor loop and hourly RAP updates reveal a
mid level speed max quickly approaching. In fact, IR satellite
imagery shows some cooling cloud tops advecting northeast through
PA/NJ. This should at least enhance the cloud coverage across the
region through the day. Per BUFKIT profiles and HRRR/HRRRX, seems
enough mid level drying should hold off more scattered showers as
we will reduce PoPs back to slight chance with some drizzle.
Prev Disc...The next impulse rotating around the upper level low
arrives late in the day and into the evening with an increase in
isolated to scattered showers once again based on the
GFS/NAM/ECMWF. Pops were gradually increased from the west late in
the day...as the cutoff opens...and migrates downstream over
upstate NY. With the pocket of cold air aloft and some weak
elevated instability a slight chc of thunder was placed in the
forecast north of the Mohawk River Valley.
Highs today will be slightly warmer than yesterday with 60-65F
readings in the valley areas...and mid 50s to around 60F over the
hills and mountains.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
Tonight...The upper low drifts over upstate NY and western New
England. Isolated to scattered showers may continue to linger
associated with the cold pool and cyclonic vorticity advection
with the low. The coverage of showers should lessen
overnight...and a few breaks in the clouds with a saturated air
mass will promote some patchy fog. Lows will be cool in the upper
to mid 50s across the forecast area.
Monday...The core of the cold air with the upper level low will be
over the region. The h500 temps will be in the -18C to -20C range
with the cold pool. Instability showers and isolated
thunderstorms will be possible due to the steep mid level lapse
rates and weak amounts of instability. Wouldn`t rule out some pea
size hail with some of the thunderstorms. The good news is that
the upper low scoots east of the fcst area by the evening. The
showery activity should dwindle with the loss of the diurnal
heating. Highs will be warmer than Sunday with some intervals of
sunshine. Mid 60s to upper 60s will be common in most
locations...aside for some 70F readings in the mid-Hudson
Valley...and upper 50s to lower 60s over the mtns.
Monday night into Tuesday...The upper low finally loses its grip
on the region with mid-level ridging building in over the Northeast
and East Coast. A closed H500 anticyclone sets up over NY with
strong subsidence. A few isolated showers may linger into early
Tuesday over the Mid-Hudson valley and NW CT. After lows in the
mid 40s to lower 50s with clearing skies. High temps with some
sunshine with the ridge building will reach the mid to upper 60s
in the Hudson and Mohawk River Valleys...and upper 50s to mid 60s
over the hills and mountains.
Tuesday night...High pressure builds in aloft and at the sfc over
the Northeast with clearing skies and light to calm winds. Near
ideal radiational cooling conditions will produce highs in the
40s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A ridge of high pressure centered over Maine and Nova Scotia, and
ridging down the East Coast, should keep our weather fair Wednesday
through Friday, with temperatures averaging slightly above normal.
Expect high temperatures to range from the 60s to lower 70s, with
overnight lows mainly in the 40s to lower 50s. Biggest challenge
through early Friday will likely be potential for nighttime fog
formation, and morning dissipation times for any fog/low clouds.
Also low temperatures may be around 5F colder than currently
forecast if subsidence under high pressure mixes dry air to surface.
This drier air combined with longer October nights and light winds,
would make for ideal radiational cooling and min temps could be
lower.
For Saturday, the forecast will entirely depend on the ultimate
track of Matthew, as well as any possible northern stream
interactions with Matthew and associated tropical moisture. At
this time, Matthew still looks to be south of Cape Hatteras, NC on
Saturday, but due to considerable uncertainty lingering, have
indicated chc pops for rain during this period. Please refer to the
National Hurricane Center, as well as the Weather Prediction Center,
for more specific details related to the track/evolution of Matthew
and potential interactions of Matthew with tropical
moisture/northern stream systems.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
Large stacked low pressure system now over Michigan,
will continue to bring a moist southerly flow to the TAF sites
during this TAF period. Later today, the winds turn more south to
southwest, and some breaks in the overcast may occur as suns heating
mixes the atmosphere. Isolated to scattered showers and
thunderstorms are expected to develop in Central and Western new
York later today and may reach the TAF sites this evening before
dissipating. For now have left out of TAFs due to scattered coverage
of storms.
Mainly MVFR conditions expected this morning, improving to VFR at
KALB and KPOU later today. Low clouds forecast to linger at KGFL and
KPSF. Tonight, fog will develop where breaks in the clouds occur and
we have forecast low IFR at KALB and KPOU. Low clouds forecast to
hang tough at KGFL and KPSF with possibly some restrictions to
visibility in fog, but clouds look to limit dense fog there.
Winds will start out light from the southeast this morning
increasing to 5 to 10 knots from the south or southwest later today.
Winds will remain southerly Saturday night at 5 knots or less.
Outlook...
Monday Night: Low Operational Impact. Slight Chance of SHRA.
Tuesday to Friday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
An upper level low will continue to bring mostly
cloudy and cool conditions with isolated to scattered shower today
into Monday. The upper low will move east of the region Monday
night. High pressure will bring fair and dry weather for Tuesday
into Wednesday with temperatures trending above normal.
The min RH values will be high this afternoon and Monday in the
65 to 80 percent range. The RH values will rise to 90 to 100
percent tonight.
The winds will be east to southeast at 5 to 15 mph today...and
light and variable direction at 10 mph or less tonight...and north
to northeast at 5 to 10 mph on Monday.
&&
.HYDROLOGY...
No hydro problems in the Albany Hydro Service Area /HSA/ the next
5 days ending Thursday.
The latest US Drought Monitor continues to show drought conditions
across much of the region. Precipitation departures this calendar year
have been 3 to 12 inches below normal, with the greatest
departures across southeastern parts of the HSA. As a result,
streamflow and ground water levels have been running below normal.
Some additional rainfall is expected today into Monday associated
with a slow moving upper level low drifting across the area. Most
locations will see an additional tenth to half inch of rainfall
through Monday.
Dry weather will return for Tuesday into Thursday.
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...Wasula
NEAR TERM...BGM/Wasula
SHORT TERM...Wasula
LONG TERM...SND
AVIATION...SND
FIRE WEATHER...NAS/Wasula
HYDROLOGY...NAS/Wasula
Area Forecast Discussion
National Weather Service Bismarck ND
929 AM CDT Sun Oct 2 2016
.UPDATE...
Issued at 926 AM CDT Sun Oct 2 2016
Made some minor adjustments to sky cover and PoPs based on latest
satellite and radar trends. Main adjustment was to extend pops a
little farther east into the south central this morning but
diminishing before reaching the Missouri River. No adjustment to
temperatures at this time.
UPDATE
Issued at 647 AM CDT Sun Oct 2 2016
Updated POPs a bit to better reflect regional radar and trends,
otherwise the forecast remains on track.
&&
.SHORT TERM...(Today and tonight)
Issued at 344 AM CDT Sun Oct 2 2016
Another warm day is expected today, and in most areas it will be
dry, as well.
Early this morning, showers and weak thunderstorms are approaching
western ND in association with a weak, northeastward-moving short-
wave trough. This activity has been moving a bit faster than HRRR
and other convection-allowing model guidance has suggested, but
simple extrapolation suggests it will continue to move across the
western and especially northwest corner of the state through the
mid-morning hours. By afternoon, another, weaker vorticity maximum
embedded in southwest flow aloft is forecast to move from western
into north central ND, but we downplayed the chance of convection
with that wave since overall forcing is weak, and more importantly
both NAM and GFS forecast soundings suggest a notable mid-level
capping inversion will yield considerable MLCIN across the area
this afternoon and evening.
Highs today, based on the multi-model consensus but then weighted
toward the warmer side of the guidance envelope in the south where
we expect more sunshine, are forecast to mainly be in the 70s F. A
few 80 F readings are again possible in the south given mixing to
about 850 mb.
It will be mild tonight, and weak height falls will begin aloft.
However, the lack of a stronger low-level jet suggests the
probability of convection is rather low before daybreak Monday.
.LONG TERM...(Monday through Saturday)
Issued at 344 AM CDT Sun Oct 2 2016
Potential impacts in the long term forecast period include strong
southerly winds Monday in southern ND, the risk of strong to
isolated severe thunderstorms west and perhaps south central from
Monday afternoon through Monday evening, and a potential freeze in
many areas by Thursday night/Friday morning.
Synoptically, the 00 UTC global models were very closely clustered
in their depiction of a deep 500-mb low ejecting from the northern
Great Basin Monday morning, to near Billings by Monday evening. As
the cyclone occludes, it is then forecast to only slowly move into
southeastern Saskatchewan by 12 UTC Wednesday. The last 24 hours
of model cycles have strongly favored a stacked low that moves to
the west of the ND/MT state line, keeping western and central ND
in the dry conveyor belt of the system behind a Pacific cold front
forecast to cross the area Monday night. In fact, not one member
of the 00 UTC GFS ensemble even scraped western ND with the 500-mb
low. The 00 UTC ECMWF is a bit further east, and does suggest some
deformation-induced precipitation could impact extreme northwest
ND Tuesday night and Wednesday, but that solution is admittedly a
bit of an outlier. Suffice to say then that this forecast release
once again reduced the chance of precipitation this week, beyond
Monday night anyway, when showers and thunderstorms are likely in
the pre-frontal zone with significant height falls aloft.
On Monday, as the surface low deepens to around 990 mb or perhaps
a bit less in eastern MT, low-level southerly flow will intensify
over southwest and especially south central ND. Forecast sounding
profiles from both the 00 UTC NAM and GFS in places like Bismarck
and Jamestown suggest mean mixed-layer winds near 30 kt with peak
speeds around 40 kt Monday afternoon when mass flow adjustments
will likely be maximized. Moreover, NAEFS guidance supports 850-mb
wind speeds in the 97th+ percentile over south central ND, and so
we raised winds over the multi-model consensus (closer to gridded
GFS MOS output), and it`s possible a wind advisory may be needed
over parts of southern ND and the James River valley.
Guidance suggests showers and thunderstorms may occur throughout
the day Monday, especially in the west and north, in response to
low- and mid-level theta-E advection. However, more robust and
surface-based thunderstorm development is possible by late day
from eastern MT into northwest SD and eventually western ND, when
the air mass may be characterized by MLCAPE of 500-1200 J/kg with
surface dewpoints in the middle to upper 50s F (if enough warming
occurs in the boundary layer). Given 0-6-km bulk wind differences
of 40-50 kt, organized and rotating storms are possible and that
CAPE-shear setting supports a marginal risk of severe weather. A
cluster or linear mode is likely to the storms with wind profiles
in forecast soundings showing a veer-back-veer signature aloft.
Given that and marginal boundary layer moisture, we are not that
concerned about tornado potential despite near-surface veering of
the winds and 0-1-km bulk wind shear values near 20 kt. Hail and
wind of the marginally-severe variety is likely to be the focus.
We expect a wave of showers and storms to then shift northeast
across the area Monday night ahead of the cold frontal passage.
That`s the most likely time frame for wetting rains with this
system. The northern and eastward extent of any strong/severe
storm risk is dependent on the width of the instability axis,
which is somewhat uncertain.
Thereafter, cold air advection will occur through the week, and
guidance supports sub-zero 850-mb temperatures Wednesday night
through Friday. MOS-based guidance still strongly supports the
potential for a rather widespread and potentially hard freeze
Thursday night/Friday morning, especially in western ND in the
closest proximity to a surface ridge axis. Not one of the 00 UTC
GFS ensemble MOS members keeps temperatures above 32 F Thursday
night/Friday morning at Williston, Minot, Dickinson, Hettinger,
or Bismarck.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 926 AM CDT Sun Oct 2 2016
Scattered rain showers and possibly a VCTS possible this Sunday
morning over western and north central North Dakota. Updated to go
with a VCTS for KISN-KDIK through around 15 UTC. Additional
showers and/or storms possible northwest and north central Sunday
afternoon and evening, and again late in the period west. Overall
VFR conditions will prevail.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...TWH
Area Forecast Discussion...Updated
National Weather Service Billings MT
934 AM MDT Sun Oct 2 2016
.UPDATE...
Strong dynamics were forecast to move into the area today and
tonight as the pacific trough becomes negatively tilted. Upper
divergence from jet energy in the E side of the trough will
increase over the area through tonight as well as upper
diffluence. Waves will move through the flow as well, with strong
q-vector convergence reaching the W and central zones tonight.
Precipitable waters were highest in the E this morning, but will
spread out over much of the area through tonight. The above will
support increasing precipitation chances through tonight. Adjusted
morning PoPs based on radar and lightning data showing showers and
thunderstorms lifting out of SE ID and N WY into the forecast
area. The HRRR/CONSShort had a good handle on this situation.
Added slight chance of thunder to the SW mountains. For the
afternoon, RAP soundings showed some elevated instability into
KBIL and the SREF had possible 500 J/kg of MUCAPE along with
decent shear over much of the area. So, added slight chance of
thunder to the rest of the PoP area. Made small sky/wind
adjustments based on latest observed and model trends.
Precipitation chances will be much higher tonight as the stronger
dynamics reach the area. Arthur
&&
.SHORT TERM...valid for Tdy and Mon...
Some busy weather coming in the short term period.
Cold front has pushed east of our cwa with some trailing showers
and thunderstorms near Miles City and Baker as of 3 am, which
should exit our cwa by 12z. Stable surface high pressure is
building from the west, but there is weak PV lifting out of north
central WY which may produce some light post-frontal showers
across our south/east parts early this morning. Isentropic ascent
will spread up from western WY by 15z or so, see backed mid level
winds near KJAC, and would expect potential for showers to
increase over our southwest by then. Our west and south will be
the focus of shower potential this afternoon as upper flow
continues to back in response to approaching Pacific trof. Airmass
is certainly moist and unstable enough for showers and risk
thunder over our mountains and foothills, but easterly surface
winds associated with cool lee side surface high will result in
capping for our central and eastern lower elevations. So will keep
highest pops over our west today.
Things get much more interesting tonight as flow aloft becomes
increasingly diffluent and precipitable waters rise to anomalously
high levels (0.75-1.00 inches), with elevated instability. Will
keep likely pops w/ expectation of bands of showers and embedded
thunder through the night. Forcing will become quite strong Monday
into Monday night as upper low lifts from the northern great basin
into eastern Montana, and models are now in pretty good agreement
with this track. QG forcing will be strongest over the west half
of our cwa, and this is where heaviest and most widespread
precipitation will fall. Dry slot will surge out of northeast WY
and into our far eastern zones on Monday. Ahead of this dry push
and on eastern edge of developing sfc low, there is increased
potential for thunderstorms, a few of which may be strong as
lifted indices fall to near -3C with plenty of bulk shear. SPC has
an area from Ekalaka to Baker and Plevna in a marginal severe risk
on Monday, quite interesting for early October, and will add
mention of strong storms to our messaging today. Further west
where precipitation will be widespread, cold air will deepen
steadily through the day on Monday, and snow levels will fall.
Given the strong forcing and high moisture content, have issued a
winter storm watch for our western mountains from Monday thru
Tuesday, with greatest amounts of 12-18 inches possible above 8kft
in the Beartooth/Absaroka and Crazy Mountains. Accumulating
snowfall will impact recreation in the high country as well as
Beartooth Pass.
Total precipitation from today through Tuesday should be in excess
of an inch over much of our western cwa, with up to two inches in
orographically favored areas like the Crazy Mountains.
West to northwest winds will also steadily increase Monday and
Monday night as surface and upper lows become stacked over
northeast Montana. 850mb winds increase to in excess of 40 kts
across our north/east by 12z Tuesday per both the GFS and ECMWF.
Windy conditions will develop as precipitation begins to taper or
lighten late Monday night as low shifts north.
Cooling trend is underway and temperatures will max out in the
60s to mid 70s today in the post-frontal airmass. Highs on Monday
will not get out of the 50s in our west, with 40s possible in the
afternoon in fact, but we will see a surge of warmer air and temps
well into the 70s across our east from Broadus to Baker. Will be
an interesting temperature gradient from west to east for sure on
Monday.
JKL
.LONG TERM...valid for Tue...Wed...Thu...Fri...Sat...
The upper low will lift into northeast Montana on Tuesday,
putting the area under cyclonic flow aloft. Wrap-around showers
will transit the area during the day with the best precipitation
chances across the north. As the upper low lifts off to the north
and east, the pressure gradient will tighten across the area
allowing for gusty northwest surface winds to develop on Tuesday.
Shower activity will continue to decrease Tuesday night into
Wednesday, although showers remain possible across the west on
Wednesday as a shortwave drops south and east from the Pacific NW
and digs over the Great Basin, putting the area in a split flow.
Winds will not be as strong on Wednesday. Shortwave ridging then
looks to build in over the Northern Rockies for Thursday and
Friday bringing generally drier conditions. Another disturbance is
then progged to move through the region over the weekend bringing
some showers to the area, although there are model differences in
the timing and location of the wave.
High temperatures are expected to be in the 40s and 50s Tuesday
through Thursday for the lower elevations, with Wednesday being
the coolest day. The area may see the first freeze of the season
Wednesday night with low temperatures expected to be in the upper
20s to lower 30s. Temperatures will gradually warm into the lower
60s for the weekend. STP
&&
.AVIATION...
Light rain just starting at SHR will remain for the next hour or
two, but expect VCSH through mid-day. Webcams show a little BR and
broken 700 ft CIG around MLS but this should clear out within the
next hour. -SHRA moves in between 00Z-03Z at LVM,BIL,and SHR and
should reach MLS around 06Z. Walsh
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Mon Tue Wed Thu Fri Sat
-------------------------------------------------------
BIL 067 052/056 043/052 040/049 035/051 039/057 043/059
2/T 78/T 84/W 22/W 11/B 11/B 21/B
LVM 063 045/051 039/048 035/046 031/050 035/055 040/057
5/T 78/T 74/W 33/W 22/W 11/B 22/W
HDN 070 051/061 042/051 039/049 034/052 036/058 041/061
2/T 66/T 85/W 22/W 11/B 11/B 11/B
MLS 073 057/072 044/049 037/048 032/050 033/057 042/060
1/B 73/T 45/W 32/W 11/B 11/B 21/B
4BQ 074 057/076 042/053 036/049 030/050 032/057 040/063
1/B 43/T 32/W 11/E 11/B 11/B 11/B
BHK 073 055/073 043/051 036/046 030/048 030/053 038/059
1/B 45/T 32/W 22/W 11/B 11/U 11/B
SHR 072 051/065 042/052 037/049 033/050 034/056 039/061
3/T 54/T 53/W 22/W 11/B 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Watch in effect from Monday morning through
Tuesday afternoon FOR ZONES 67-68.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service State College PA
1142 AM EDT Sun Oct 2 2016
.SYNOPSIS...
An upper low will drift east across the southern peninsula of
Ontario today...keeping a deep-moist southerly flow over the
region. A ridge of high pressure will build east into Pennsylvania
behind this system early in the new week, and will likely remain
over the area through the middle, and perhaps end of the work week
bringing mainly dry and slightly milder conditions across Central
Pennsylvania.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As the upper low begins to kick out and move toward the St
Lawrence River Valley, at least one shortwave can be seen rotating
around the system and is kicking off some scattered showers that
are now moving into my western zones. The RAP meso anal shows some
marginal instability with mid level lapse rates in excess of 6C/km
over the NWRN 1/3 portion of the region.
HRRR takes the showers and tracks them eastward while showing an
overall tendency toward becoming more scattered and disorganized
as we move into the afternoon. Can`t rule out a rumble of thunder
given the smidgen of instability that is observed, but the lack
of sunshine will keep instability at a minimum.
Temps will rebound a bit above Saturday`s levels, reaching the
mid 60s over the NW and ranging to the lower 70s over the SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Partial clearing is expected tonight across the south-central
cent mtns and Lower Susq Valley while plenty of clouds and a few
isolated to scattered showers drift across the region north of
Interstate 80.
lows tonight will vary from near 50F over the high terrain of the
north and west to the mid and upper 50s in the SE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Fair weather will follow with a slight chance for showers across
the north early next week.
Surface high pushing the cooler air our way slides off the New
England coast midweek, and creates an easterly low level flow once
again with a long fetch of moisture aimed at southern PA.
This should create plenty of clouds around, along with at least a
chance for light showers/areas of drizzle across southern half of
the CWA through midweek.
Latest on Hurricane Matthew in the 00z runs - Tremendous
differences have developed between the ominous GFS and the much
more benign forecast by the latest EC for the U.S. main-land.
The 00Z GFS brings a potent Matthew across the Western Bahamas
then has it paralleling the SE U.S. and Carolina coast late in
the week...before projecting it to get captured by a deepening
upper trough and accelerating north into Long Island next Sat/Sat
night. GEFS has roughly the same track, but as expected becomes
more diffuse through time with the location and intensity of the
storm`s center just off the East Coast.
The 30/12z operational ECMWF parked the storm over or just to the
north of the Bahamas for a prolonged period during the middle to
latter part of the upcoming week, which was a low confidence
solution.
The latest 01/00Z run of the EC now carries the hurricane well to
the northeast of the Bahamas Friday and on a steady course to the
Northeast toward Bermuda by the middle of next weekend. With such
drastic differences between the GFS/GEFS and the EC 5-7 days out,
we`ll continue to play the middle of the road and note just
scattered showers with the passage of a more definitive northern
stream shortwave and sfc cold front late next week or early next
weekend.
Temperatures will be slightly below normal through the latter half
of 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 /16Z SUNDAY THROUGH THURSDAY/...
Widespread MVFR/IFR should slowly improve to MVFR/VFR by later
this afternoon. Scattered showers over western areas will progress
eastward into the afternoon hours and a rumble of thunder will be
possible, mainly over the NW.
Expect decreasing coverage of showers after 00Z with some
clearing into early Monday morning, mainly downwind of the
Alleghenies. Any clearing would likely result in patchy fog
formation during the predawn hours. Model guidance has sub-VFR
cigs redeveloping over the western 1/3 airspace late tonight into
early Monday given residual low level moisture and weak/moist
upslope flow
Outlook...
Mon...AM low clouds/patchy fog, becoming VFR.
Tue...AM visibility reductions possible in patchy fog, then VFR.
Wed-Thu...Mainly VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte/Lambert
NEAR TERM...La Corte/Lambert
SHORT TERM...Lambert
LONG TERM...Lambert/Gartner
AVIATION...La Corte/Steinbugl
Area Forecast Discussion
National Weather Service Duluth MN
640 AM CDT SUN OCT 2 2016
.SHORT TERM...(Today through Monday)
Issued at 427 AM CDT Sun Oct 2 2016
The main challenges with this forecast involves the evolution of
clouds and low stratus this morning, the degree of clearing
tonight, and associated min temperatures.
Persistent cut-off upper low was centered over southern Lower
Michigan early this morning with a high amplitude ridge farther
west over the Central and Northern Plains and Upper Midwest. A
compact vort max was observed on water vapor imagery over
northwest Ontario, which was supporting an area of mid-level
stratus over north-central and western Minnesota. Weak northeast
winds off Lake Superior had advected fog and low stratus over
portions of northwest Wisconsin and adjacent areas of east-
central Minnesota once again. Several locations in the Twin Ports
and northwest Wisconsin have reported fog overnight with
visibilities less than 1/4 mile at times.
Expect fog and low stratus to lift and mix out through mid-
morning with increasing wind speeds and gradually warming
temperatures. Liked the slower warm up of the HRRR solutions this
morning, so trended hourly temps over Wisconsin toward HRRR blend.
Other lingering question for today is how long the clouds will
linger over northern Minnesota. The presence of the compact vort
max and available moisture seems to suggest skies will remain
partly cloudy to partly sunny into the afternoon. However,
mesoscale models have shown a consistent trend of dissipating the
cloud cover over northern Minnesota by late morning/early
afternoon. Trended toward clearing skies, as with the previous
forecast. As a result, we are still holding onto max temps this
afternoon near 70 in northern Minnesota with upper 60s in
northwest Wisconsin. Should the cloud cover be slower to
dissipate, forecast highs would be too warm.
The next concern is the redevelopment of fog and low stratus over
Wisconsin tonight and min temperatures. Winds will be less
favorable for advecting a marine layer inland overnight, so kept
fog/low stratus to portions of northwest Wisconsin adjacent to the
lake. Elsewhere, continued the clearing trend from previous
forecasts. Model consensus also indicates mainly clear to partly
cloudy skies overnight. With relatively light winds and mostly
clear skies anticipated, nudged min temps a bit cooler over
northwest Wisconsin and portions of the Arrowhead. This matches up
well with some of the high-resolution guidance and collaboration
with neighbors. Look for temps overnight around 40 in north-
central Wisconsin and far northeast Minnesota, and near 50 degrees
in my western zones.
The resident cut-off low will be well east of the Northland by
Monday morning while the next significant upper-level trough
pushes into the Rockies. Southerly breezes will develop through
the day with the approaching low and mainly sunny to partly cloudy
skies should be the norm. The southerly winds should result in
cooler temperatures over northeast Minnesota thanks to the
influence of Lake Superior. Look for highs in the upper 50s over
southern Lake and southern Cook Counties to the upper 60s to low
70s elsewhere.
.LONG TERM...(Monday night through Saturday)
Issued at 427 AM CDT Sun Oct 2 2016
A period of heavy rainfall expected mid-week followed by some of
the coldest temperatures so far this fall late-week. Another
chance for precipitation late-week, with some scenarios leading to
the first snowflakes of the season for parts of the Northland.
Temperatures gradually warm through next weekend but remain a few
degrees below normal.
On the synoptic scale an upper low gradually moving across the
Great Basin and northern Rockies will be the feature of interest
as a resulting surface low develops over the northern High Plains
into southern Saskatchewan and southern Manitoba mid-week. The
deepening low combined with a longwave mid-level ridge over New
England will result in strong southerly flow through much of the
column Monday through Wednesday ahead of a cold front, bringing
warm moist air to the upper Midwest. Precipitable water values
will rise to 1.20 to 1.45" - not especially notable if this were
mid-summer, but for early October these values are approaching the
90% percentile levels compared to climatology. As the surface cold
front approaches from the west late Tuesday and crosses the
Northland Tuesday night through Wednesday, rain is expected along
and ahead of the front. At this point guidance is in fairly good
agreement with the bulk of this precipitation occurring late
Tuesday night when a very strong low level jet (on the order of
50-60+ knots) will result in a period of heavy rainfall with
occasional thunder across parts of northern Minnesota. A narrow
north-south oriented corridor of 2"+ will be possible, and WPC has
included much of Minnesota within a Marginal risk for flash flood
potential, with a Slight risk for parts of central Minnesota near
the Brainerd Lakes and Lake Mille Lacs areas, which we agree with.
Temperatures ahead of the front will be very warm Tuesday with
highs in the mid 60s to low 70s - 10 to 15 degrees above normal
(though far from the record of 83 at Duluth). Low temperatures on
the other hand will be VERY warm in the 50s Monday night, mid 50s
to near 60 Tuesday night - near record values compared to the
average low in the upper 30s.
The cold front moves from west to east across the Northland
Wednesday leading to cooler temperatures, with rainfall possibly
lingering through the day. Another round of precipitation is
possible sometime Thursday into Friday as a mid-level shortwave
trough quickly lifts across the central Great Plains into the
upper Midwest (GFS a slower solution, ECMWF a bit faster). In
either scenario the cold front will be stalled across western Lake
Superior, and behind the front in the Minnesota Arrowhead a mix of
rain and snow is possible Thursday or Friday night due to near-
freezing temps at the surface and aloft. Should the precipitation
fall during the day temperatures would be too warm to support
snow, but any overnight precipitation across the Arrowhead either
night (more likely Fri night) could lead to some snow. Little to
no accumulation expected at this time. Temperatures still on the
mild side Wednesday with highs int he low to mid 60s (highs
possibly occurring early in the day with temps falling through the
afternoon depending on the frontal passage timing). Cooler behind
the front -lows in the 40s Wednesday night, highs in the 50s
Thursday then upper 30s to low 40s Thursday night. The coolest air
arrives Friday into Saturday with highs in the mid 40s and lows
Friday night in the mid to upper 30s - a few locations falling to
near freezing.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 640 AM CDT Sun Oct 2 2016
VFR conditions will prevail through the TAF period throughout
northeast Minnesota...with IFR to VLIFR conditions this morning at
HYR, then VFR through the day. Morning fog/stratus at HYR will
stick around for a few hours this morning but should dissipate mid
to late morning. Scattered mid to high level clouds possible
through the day at all sites...but conditions will remain VFR.
Light east to southeast wind today and tonight at around 5 mph or
less. Late tonight fog may return to HYR but it does not look as
widespread or dense, so went with MVFR visibility for now.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 67 43 63 52 / 0 0 0 0
INL 71 48 70 54 / 0 0 0 0
BRD 71 48 70 56 / 0 0 0 10
HYR 69 42 69 54 / 0 0 0 0
ASX 63 42 65 54 / 0 0 0 0
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...Huyck
LONG TERM...JJM
AVIATION...JJM
Area Forecast Discussion
National Weather Service Grand Forks ND
936 AM CDT Sun Oct 2 2016
.UPDATE...
Issued at 936 AM CDT Sun Oct 2 2016
Spotty radar returns continue, and the HRRR and RAP have some
development continuing into this afternoon. Do not think much is
reaching the ground, but will continue with a sprinkle mention
through 18Z. Bumped up cloud cover a bit more during the late
morning, but still think there should be some clearing this
afternoon and kept highs in the 70s.
UPDATE Issued at 602 AM CDT Sun Oct 2 2016
Added some sprinkles in the morning across NW MN as a few occurred
in GF with an 30dBZ echo on radar. Most echos are probably virga
with very little reaching the ground. Otherwise the fog in the
east is confined to the Wadena and Staples areas with vsbys now
down to under a mile.
&&
.SHORT TERM...(Today and tonight)
Issued at 329 AM CDT Sun Oct 2 2016
Concern will continue to be temps with late day PoP chances in the
far western FA. Some morning fog in the east once again has
developed although for less of an area than past mornings as thin
cirrus has helped keep temps warmer overnight. That cirrus is
expected to slowly work its way to the east with a sunny day and
light SE winds as 500mb ridge axis weakly bends to the east.
Another 70 degree day is expected for the FA with upper 60s in the
east. Shortwave bringing showers and thunder to Montana this
morning may bring isolated showers to the Devils Lake basin this
evening and early tonight.
.LONG TERM...(Monday through Saturday)
Issued at 329 AM CDT Sun Oct 2 2016
Monday and into Tuesday will see the approach of stacked low
pressure system with increasing SE winds in response to
tightening pressure gradient force. 40 to 50kt LLJ developing
early Monday will lead to a windy and warm day with max temps in
the 70s as 850mb temps mix down efficiently. PoPs spread from
west to east Monday night into Tuesday after the prolonged strong
south winds increase PWats to 1.25 to 1.5 inches. Band of warm
advection or elevated showers will move across the FA with showers
and possibly some embedded thunder. Showalter values around zero
and some elevated CAPE warrant enough of a threat to keep a
thunder mention.
From Wednesday into Thursday the 500mb low is forecast to track from
southeast Saskatchewan toward Hudson Bay. The system is nearly
vertically stacked, as the surface low also tracks along the same
trajectory. This puts most of the FA in the dry slot throughout this
time frame. Therefore the main question is whether there will
actually be any light pcpn anywhere in the FA. Overall not a big
deal, but with 925mb temps dropping to near 0C over north central
ND by Thursday morning, it could bring a few flakes of snow to areas
northwest of Devils Lake. For the rest of the Thursday night through
Saturday time frame the same goes. Pcpn chances overall look pretty
minimal and inconsistent between the various models, although if
anything occurs it looks light. Daytime highs look well below normal
with overnight lows flirting with 32F. Therefore if any light pcpn
managed to fall during the overnight periods, a few flakes of snow
would be possible.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 602 AM CDT Sun Oct 2 2016
A few SCT CIGS at 8000ft with isolated SHRA this AM in NW MN.
Will see cirrus slowly shift to the east today with light SE
winds. Possibly a shower at DVL late this evening.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...JR
SHORT TERM...JK
LONG TERM...Godon/JK
AVIATION...JK
Area Forecast Discussion
National Weather Service Gray ME
1130 AM EDT Sun Oct 2 2016
.SYNOPSIS...
Weak low pressure will approach from the west today and will
dissipate as it crosses the region overnight into Monday. High
pressure will build in from the northeast Monday night through
Tuesday and will hold over the region through Friday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
---1125am Update---
Fog... stratus and drizzle just do not seem to want to go away
today. Will update the forecast package to add some patchy fog
and drizzle into the afternoon and increase afternoon cloud cover
a bit.
---925am Update--- Radar indicating mainly dry conditions
across northern New England. There are still a few isolated
locations reporting drizzle... but precipitation should be most
done for the majority of today. However... cloudy skies and
relatively cool temperatures will prevail. Have updated the
package to make only very minor changes to account for current
trends.
625 AM...Updated to better time pops of exiting showers to the
east, and to take DZ out of the forecast. Added slight chc pops
today, based on NAM12 and HRRR as we may get some SHRA popping up
as ridging aloft breaks down and we see some weak height falls.
Previously...Weak 500 mb ridging builds up this morning before
500 mb closed low over the midwest US begins to track NE and
increases 500 mb flow aloft, which slow produce little if, any
dynamic forcing, with weak relative ridging at the sfc. Ne flow
will wane during today, and conditions will be more stagnant, so
look for clouds to linger, although threat of showers will be very
limited through today. could see some drizzle this morning in the
weakening NE flow in CW ME and srn NH, but this looks limited, and
could even a few brief breaks of sun this afternoon, especially
away from the coast. Maxes will stay within a degree or two 60 in
most places.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
Tonight the filling closed low will open and approach the CWA as a
trough will will cross the region on Monday. Stagnant flow should
see a return of low clouds to most of the CWA, and maybe some fog
at the coast and in the river valleys. Could see a shower in the
mtns late tonight. Mins will generally be in the upper 40s to low
50s again.
As 500 mb trough crosses the CWA Monday could see a chance of a
shower, but also will see more subsidence as mid level flow shifts
to the north and some downsloping occurs. So, will see some breaks
of sun during the day despite a threat for showers. 850 mb temps
remain a little above normal, and temps should responds to some
mixing and some sun with highs reaching to the mid to upper 60s in
all but the mtns, where they will be limited to the the low 60s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
High pressure will build in from the northeast Monday night and
Tuesday. After a mostly cloudy Monday night expect low level
moisture to gradually diminish on Tuesday as onshore flow is
suppressed to the south. Lows Monday night will range through the
40s and highs on Tuesday will top out in the upper 50s to lower
60s.
Expect skies to become mostly clear Tuesday night as high pressure
continues to build in from the east. Lows will range from the upper
30s to the mid 40s.
High pressure will gradually weaken Wednesday through Thursday but
will remain in control of weather across the northeast with mostly
clear skies and moderating temps. Highs on Wednesday will top out
in the lower to mid 60s and Thursday will be slightly warmer with
highs in the mid to upper 60s. Overnight lows will be in the 40s.
High pressure will hold on for one more day on Friday with mostly
sunny skies and highs ranging through the 60s to near 70.
High pressure will pull off to the east Friday night allowing an
increasing onshore flow to push ocean stratus into southern New
Hampshire and southwestern Maine. Lows overnight will range from
the upper 40s in the north to the mid 50s in the south.
At this point attention turns to Matthew which is forecast to
head northward over the weekend. Models still showing a variety
of tracks but are slowly converging on a more northward
movement. How much affect this will have on northern New England
is too early to determine considering major differences between
model solutions. Shortwave swinging in from the west will add to
the complexity of the weekend forecast as it interacts with some
degree of tropical moisture. Potential will be there for some
much needed rainfall for parched sections of New England but exact
location of this rainfall is still very much in doubt.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
Short Term...Condition are quite variable at the terminals this
morning, but should see a trend toward IFR, at least briefly for a
few hours around sunrise. Improvement to MVFR is expected this
afternoon, before we see all terminals head to IFR or lower
around or shortly after sunset. Should see improvement to VFR
Monday morning.
Long Term...areas of MVFR/IFR ceilings Monday night...improving
to VFR on Tuesday. VFR Wednesday and Thursday.
&&
.MARINE...
Short Term...NE flow begins to weaken later this morning, but
lingering swell will keep the seas high through the afternoon.
After that, sfc high builds in and winds should remain light
through Monday, with slowly diminishing seas.
Long Term...High pressure will keep winds light over the waters
Monday night through Thursday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory for hazardous seas until 6 PM EDT this
evening for ANZ150-152-154.
&&
$$
Pohl
Area Forecast Discussion
National Weather Service Wilmington OH
1053 AM EDT Sun Oct 2 2016
.SYNOPSIS...
A large slow moving upper level low will drift slowly northeast
through the southern Great Lakes, resulting in a few lingering
showers today. High pressure will then build into the region,
leading to dry conditions and a warming trend through the middle
of the week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Not many changes to the forecast this morning as the upper level
low continues to eject northeast. Surface analysis revealed a
trough axis stretching from Toledo down to Indianapolis with weak
confluence along the axis. PWATs have fallen slightly since
Saturday (0.92" from KILN 02.12Z sounding) with slightly drier
650 mb to 300 mb moving in. ML Cape values on RAP and NAM forecast
soundings are around 100 J/kg with slightly higher values
anticipated by the NAM. Have limited PoPs to slight chance as
forcing from the trough axis appears to be weak. New zones already
out.
Prev Discussion->
Upper low evident on water vapor imagery centered over se lower
Michigan this morning. Model solns generally similar with the upper
low drifting ene into srn Ontario today. Expect to see more in the
way of sunshine. In the broad cyclonic flow around the periphery of
this low can not rule out afternoon showers. The best threat for
showers will occur across the ne counties. Expect highs today to
range from the upper 60s north to the lower 70s south.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
As the upper low drifts into se Canada and opens up, surface high
pressure begins to build into the region. With the upper low finally
losing it`s grip on the region, will end any mention of showers
early this evening. Clouds will scatter out with lows in the lower
50s.
Surface high pressure builds in from the west becoming centered over
the Great lakes Monday. Expect dry conditions with temperatures near
normal Monday. Highs to range from around 70 north to the
lower/middle 70s south.
Under the influence of this high expect mainly clear sky conditions
Monday night with lows in the lower and middle 50s.
The ridge axis slides a little east Tuesday with a southerly flow
developing. A warming trend will develop with highs in the mid and
upper 70s.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Upper level ridge extending from New England into the Gulf of Mexico
will keep dry and warm conditions across the region into Thursday. A
trough will move from the Plains into the Great Lakes and Ohio
Valley late in the week. 12Z models continue to show discrepancies
in timing which may be related to the handling of Hurricane Matthew
off the Atlantic coast. Have leaned toward ECMWF for timing which
would push a cold front through the region on Friday with a chance
of post-frontal showers. This will bring temperatures down closer to
normal by Saturday.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
Aviation continues to be affected by an upper low currently near
Detroit. Though most precip is now north of TAF sites and only a
few showers may occur in the vicinity of northern TAF sites, ceilings
as low as IFR have formed in the moist circulation around the
southern flank of the low. Ceilings will increase to VFR when
drier air begins to filter in by 18z as the low travels farther
northeast through the lower Great Lakes. As surface high pressure
builds in tonight, BR may reduce visibilities at ILN and LUK late
in the forecast period. Winds will shift from south to west with
speeds staying under 10 knots.
OUTLOOK...No impacts to aviation expected.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Haines/AR
NEAR TERM...Haines/AR
SHORT TERM...AR
LONG TERM...
AVIATION...Coniglio
Area Forecast Discussion
National Weather Service Lincoln IL
931 AM CDT SUN OCT 2 2016
.UPDATE...
Issued at 930 AM CDT Sun Oct 2 2016
Widespread stratus remains in place across the area this morning,
but earlier patchy dense fog has lifted to at least a few miles
visibility over most areas. Some thinning of the clouds seen in
visible satellite imagery around Bloomington and Peoria, and some
additional holes should break through with time, with partly sunny
skies expected by afternoon. Updated grids for the fog and sky
trends have been sent, and will follow up with some updated zone
forecasts once more of the fog has lifted.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 324 AM CDT Sun Oct 2 2016
The initial concern is where dense fog will form early this morning.
Varying cloud cover is adding difficulty to that determination. Any
areas with a period of clearing have seen visibility drop to less
than a mile, while visibility in cloudy areas remains 5SM or better.
A dense fog advisory may be needed along and south of I-72 per the
HRRR guidance, but will hold off due to uncertainties in cloud cover
progression. Satellite loops confirm there are plenty of upstream
clouds to rotate south over our CWA, so that could preclude
widespread dense fog even in our south. Will monitor closely for
possible need for an advisory.
An elongated surface low from north to south in western
Indiana will linger nearby long enough today to keep plenty of cloud
cover in place across central and southeast Illinois. HRRR and RAP
output are pointing toward spotty showers or sprinkles possible in
most areas this afternoon, but the overall consensus of rain chances,
including the GFS/NAM/ECMWF models, seems to be along a trailing
lobe of low pressure across our southern forecast area. We kept
slight chance /20%/ PoPs going this afternoon south of Springfield
to Effingham to Robinson. We may see spotty sprinkles north of
there, but we left a dry forecast in place for today.
High surface pressure will progress into Illinois tonight, with dry
mid level air pushing into the area. However, time-height RH
analysis confirms that low level moisture content will remain high,
allowing for clouds to develop in any clearing areas that possibly
develop later this afternoon. Will continue to mostly cloudy skies
even Sunday night, which will limit the diurnal temperature range,
as lows bottom out in the middle 50s. Fog will likely form again
tonight, with areas of dense fog in areas that clear out for any
period of time.
.LONG TERM...(Monday through Saturday)
ISSUED AT 324 AM CDT Sun Oct 2 2016
Large 564 dm 500 mb low pressure over southeast lower Michigan will
lift out into southern New England by sunset Monday, while upper
level ridge shifts east over IL and central Great Lakes. Weak
surface high pressure ridge of 1020 mb from MN south into AR will
drift east over IL and ohio valley tonight and into New England and
eastern Canada on Monday. Areas of fog and locally dense early
Monday morning will lift during mid Monday morning with skies
becoming partly sunny with lingering scattered to even broken
cumulus clouds. Seasonable highs Monday in the low to mid 70s.
Fair skies Monday night with lows of 53-58F, coolest near the
Indiana border where winds will be lighter closer to high pressure.
Patchy fog could develop over eastern IL later Monday night.
Cutoff upper level low pressure off the WA/OR coast will track into
eastern MT by sunrise Tue and eject northeast into southern Manitoba
on Wed, while upper level ridge shifts east to the eastern seaboard.
1030 mb high pressure over New England Tue/Tue night to ridge WSW
into the ohio valley and keep CWA dry and milder. Highs Tue in the
upper 70s to near 80F with southeast winds. Lows Tue night mostly in
the lower 60s with a few upper 50s from Champaign and Paris
northeast.
00Z models show a piece of energy ejecting northeast across the
upper Midwest on Wed and bringing good chances of showers and
thunderstorms to the IL river valley Wed and Wed night while just
slight chances over southeast IL later Wed afternoon into Wed night.
Warm highs Wed mostly in the lower 80s, ranging from 78F by
Galesburg to 84F by Lawrenceville. Models have trended slower with
arrival of cold front on Fri instead of Thu like yesterdays runs.
Therefore warmed highs on Thu quite a bit, into the upper 70s and
lower 80s. Also have higher pops over nw CWA on Thu and lower pops
in southeast IL further from the front. Models show surface low
pressure near KS/OK border on Thu ejecting northeast into the
western Great Lakes by Fri morning and then pulling the cold front
east over IL on Friday. This will continue chances of showers and
isolated thunderstorms on Friday and Fri evening, then diminishing
or ending overnight Friday night. High Fri range from mid 60s nw of
IL river by Galesburg to mid 70s near the Wabash river valley.
Upper level trof swings east across IL friday night then followed by
cooler and drier weather next weekend behind the cold front and
upper level trof. Highs Sat in the low to mid 60s and highs Sunday
in the mid to upper 60s. Lows Friday night and Saturday night in the
mid to upper 40s, so back to fall weather.
Powerful Category 4 Hurricane Matthew packing winds of 150 mph was
located at latitude 13.8 North and longitude 73.9 West at 2 am EDT,
moving NNW at 6 mph. Hurricane Matthew is forecast by the National
Hurricane Center (NHC) to track northward to eastern Cuba and
western Hispaniola Monday night, and near the eastern Bahamas by
Wed night. Stay tuned to later forecasts from the National
Hurricane Center if you have travel plans to the the Caribbean or
the East Coast.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 647 AM CDT Sun Oct 2 2016
The initial concern centers on IFR to LIFR cigs/vsby, which is
affecting CMI and SPI while lingering nearby the other terminal
sites. The fog will likely continue into the mid morning hours
before dissipating. Ceilings should then lift to MVFR levels until
afternoon, when VFR conditions should develop with the help of dry
air mixing down into the cloud-bearing layer. Forecast soundings
show a rather shallow layer of moisture, which will support VFR
conditions eventually developing with increased mixing.
High pressure building into Illinois for tonight will set the
stage for a subsidence inversion to trap low level moisture in
place. Therefore, it is likely that any areas that experience a
period of clear skies tonight will see another round of dense fog
after midnight.
Winds today appear to remain primarily NW, with speeds less than
10kt. Light and variable winds are expected tonight as the surface
ridge axis moves into Illinois, which will also support the
formation of dense fog and/or a low stratus layer.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1003 AM CDT Sun Oct 2 2016
.UPDATE...
1003 AM CDT
The only significant change made this morning was to add isolated
rain showers through the afternoon. Upper level vorticity
associated with the departing upper level low will rotate
overhead. Have already seen a few showers/sprinkles on radar and
think this trend will continue this afternoon. The HRRR is very
excited about the showers, but do not think they will be as
intense or frequent as the HRRR indicates. Few areas will see
measurable precip, but felt like isolated showers was more
representative than areas of sprinkles.
Otherwise the forecast is on track with cloudy conditions, light
winds, and highs in the mid to upper 60s.
JEE
&&
.SHORT TERM...
254 AM CDT
Through tonight...
Our upper low is finally beginning to shift east-northward, with
water vapor imagery early this morning showing the center
circulation now nearing KDTX (in southeastern lower MI). As a
result, this should dramatically reduce or chances for widespread
precipitation over the area. However, although today will be
mainly dry for most areas, I cant rule out the possibility of a
few isolated to widely scattered light showers or sprinkles from
time to time into the afternoon, but certainly nothing like
yesterdays rain. In spite of less precipitation potential today,
skies will likely again remain cloudy through the day. Some patchy
dense fog will also start the day early this morning in
northwestern Indiana. Temperatures this afternoon should top out
in the mid to upper 60s, which is near the seasonal average.
Skies look to try to break up some tonight and this, along with
the presence of abundant low-level moisture and light winds, may
set the stage for fog (some dense) across much of the area
overnight.
KJB
&&
.LONG TERM...
334 AM CDT
Monday through Saturday...
The main feature of interest during the extended period is the
upper low/trough currently digging onshore across the Pacific NW.
This system is expected to shift eastward across the Northern
Rockies and into the Northern High PLains on Monday. This should
induce a decent northeastward moving surface low over the western
Dakotas and southern portions of Manitoba Tuesday into Wednesday.
The main local effects from this system, at least initially, will
be the transition to a warmer air mass as breezy southerly flow
sets up over the central CONUS. This looks to push temperatures
up into the mid 70s in most areas by Tuesday, and the upper 70s
to near 80 on Wednesday and Thursday.
There will be increasing chances for some showers and
thunderstorms on Wednesday afternoon as a weakening cold front,
associated with the Canada low, approaches the area. Previous
model runs and forecasts suggested that this cold front would
move across the area in a stronger nature by late Thursday, and
essentially leaving the area colder and drier by Thursday night
into Friday. However, model and ensemble guidance are now begging
to suggest that another potent upper level disturbance, emanating
from the Northern Pacific, will dig southeastward across the
central Rockies by mid week. This could then support another
northward moving surface low over the Upper Midwest later in the
week. As a consequence of this, it appears that there could be
another wave of showers and storms into Friday before a strong
cold front pushes across the area. Cooler weather would then be
favored over the area next weekend. Given the latest trends in the
model guidance, we have upped shower and storm chances some into
Friday, but confidence on timing and specifics is low at this
time, especially given this disturbance is currently over the
North Pacific.
KJB
&&
.AVIATION...
For the 12Z TAFs...
Challenging forecast out the gate with highly variable ceilings
and visibility, but high confidence in IFR/LIFR conditions in
many locations to start the day. Earlier tonight cigs and vsbys
tanked with ORD and MDW both getting LIFR/VLIFR conditions on
cigs and even vis for a little while. High pressure is building
in from the west and with the low moving off to the east there is
enough gradient to keep conditions in the lower levels mixed
enough to prevent cigs and vsbys from holding at a particular
level but it seems like cigs are settling now. ORD/MDW are at LIFR
and expect that will be the case for a few hours. Precip to the
north will be slow moving, and most guidance does not bring much
of anything in this morning.
Will generally hold cigs in the 400-800 foot range for most of
the terminals this morning out the gate with conditions expected
to jump later this morning, possibly in a few hours if the precip
does not make it as There could be a few isolated showers today
as the last of the energy rotates southward on the back side of
the low. Limited moisture remains to preclude a mention in the
TAF as they would be brief. Winds should gradually veer NW and
towards N. Some guidance hints at a NE wind shift later
today/tonight. If that were to occur winds would still be on the
lighter side. Tonight the surface ridge will build in. Expect at
least some clearing, then with the weak onshore flow in place
expect some fog or stratus again tonight. Confidence on specifics
still low at this point but IFR/LIFR not out of the question.
KMD
&&
.MARINE...
224 AM CDT
The low pressure system that plagued the region for days will exit
to the eastern Great Lakes today, and off to New England tonight.
Several quiet days ensue as high pressure builds over Lake
Michigan tonight and then shifts to the eastern lakes Monday into
Tuesday. Southeast winds will increase Tuesday into Wednesday as
low pressure ejects northeastward from the central Rockies and
moves north of the lakes toward Hudson Bay. A weak cold front will
affect the north half of the lake mid week as the low moves well
north of the area. A stronger front will move across the lake late
in the week as low pressure moves northeastward Friday followed by
modest high pressure Saturday.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Marquette MI
745 AM EDT Sun Oct 2 2016
.SHORT TERM...(Today and tonight)
Issued at 452 AM EDT SUN OCT 2 2016
Water vapor imagery and RAP analysis show a mid level low over the
Great Lakes region with the center near Detroit. NW fringe of the
deep layer forcing associated with this feature and the minor
shortwaves rotating around it is generating a few shra across
eastern Lake Superior and the east half of Upper MI early this
morning. Coverage has diminished from the evening hrs. The w has
remained dry, and once again low clouds and fog are plaguing the far
w around KIWD as nne flow across western Lake Superior transports
warmer/more humid lake modified air upslope into the cooler air over
the land.
Mid level low will drift e across the Lower Great Lakes today. As it
does so, heights will begin to rise with deep layer q-vector
divergence/subsidence spreading across the fcst area. Thus, expect
lingering isold/sct -shra over roughly the east half of the fcst
area to end by aftn. With back edge of the clouds associated with
the mid level low currently over western Upper MI, skies will become
mostly sunny over at least the w and central fcst area today. High
temps will be in the 60s, warmest over the w half under less cloud
cover.
Sfc high pres ridge will shift over the fcst area tonight, providing
a quiet night. While some lingering clouds over the e along with a
stronger ene wind just off the sfc should reduce the potential of
fog development in that area tonight, mostly clear skies and lighter
winds under ridge axis over the w and central will lead to some fog
development tonight as temps fall back blo the expected minimum dwpt
readings this aftn. Light wind fields suggest flow off the Great
Lakes probably won`t be a factor in fog development. If there is any
marine influence, it would occur over n central Upper MI into the
Keweenaw under 950mb winds veering from ne to e. Min temps may slip
just blo 40F over the interior w tonight under best radiational
cooling. Highest readings will be along Lake Superior where temps
should mostly stay aoa 50F.
.LONG TERM...(Monday through Saturday)
Issued at 412 AM EDT SUN OCT 2 2016
Although a sfc hi pres rdg axis under a slowly progressive upr rdg
wl bring dry wx to Upr MI on Mon thru Tue ngt, lo clds in the slowly
veering e to sly llvl flow may prevail early in the week, especially
after sunset on Mon. The next chc of showers wl arrive on Wed ahead
of an aprchg warm conveyor belt/cold fnt associated with a sfc lo
pres riding newd thru scentral Canada. There is good agreement among
the guidance the fnt wl pass on Wed ngt, but the timing of a wave of
lo pres tracking to the ne along the stalled fnt on Thu/Fri under
the sw flow aloft to the w of persistent well above normal hgts that
could result in some heavier rain is still in question. Cooler wx
and perhaps some lk effect rain showers wl arrive next weekend in
the nw flow ahead of Cndn hi pres bldg into Ontarior.
Mon thru Tue ngt...Upr MI wl be under the influence of a slowly
progressive upr rdg btwn a deep trof moving thru the Rockies into
the Plains and the disturbance responsible for the showers this mrng
that wl be quickly exiting thru the ne states on Mon. At the sfc, a
hi pres center over far NW Quebec on Mon wl extend a sfc rdg axis
into the Upr Lks, resulting in dry wx under the large scale
subsidence. But as the llvl flow veers more to the se during the day
as the sfc hi pres drifts to the e, some of the models show incrsg
llvl mstr advctn and the potential for some lo clds to spread into
the area, especially the scentral with upsloping off Lk MI. As the
sfc hi pres moves into the Cndn Maritimes on Tue, the llvl flow wl
veer further to the s and incrs under the tightening pres gradient
btwn the hi and falling mslp in the nrn Plains ahead of the upr trof
shifting to the e. Even though the mid lvl dry air/subsidence under
the upr rdg wl allow continued dry wx, this s wind wl enhance llvl
mstr advctn under sharpening subsidence invrn into the cwa. Fcst
sdngs sug a good deal of lo clds wl prevail Mon ngt thru Tue ngt
with this setup. There could be some dense fog on Mon ngt over
mainly the scentral. Best chc for some breaks in this lo cld cover
wl be over the downslope areas near Lk Sup. H85 temps are fcst to
rise fm arnd 9C on Mon to as hi as 12C on Tue over the w, where the
sly flow wl downslope. So expect abv normal temps to prevail. With
the lo clds and steady s winds, the min temps anomaly fm normal wl
be most sgnft.
Wed thru Fri...While the nrn portion of the wrn trof is fcst to make
progress to the ene and allow a fairly deep sfc lo pres to move fm
the nrn Plains into Hudson Bay, many of the medium range models
indicate the srn portion of the trof wl hang back over the srn
Rockies thru at least Thu. As the lo ahead of the nrn portion of the
trof shifts to the ne, it is fcst to drag a cold fnt acrs the Upr
Lks on Wed ngt. Since the more impressive dpva/hgt falls are fcst to
pass to the nw of Upr MI, pcpn ahead of the cold fropa that wl
arrive w-e on Wed may not be too heavy despite fcst pwat up to about
1.5 inches under the warm conveyor belt in advance of the fnt. But
since the srn portion of the trof wl hang back to the w of a
lingering upr rdg/well abv normal hgts over the se states and
maintain a sw flow alf over the Great Lks, the fnt should stall not
far fm Upr MI. Depending on how quickly the srn portion of the trof
lifts to the ne, a sfc lo pres wave ahead of the disturbance could
ride ne along the stalled fnt into the Upr Great Lks and drop some
heavier rain on Thu/Fri as hinted by the 00Z GFS/12Z ECMWF. While
there wl be some cooling in the wake of the cold fropa after Wed and
perhaps toward normal by Fri, above normal temps should persist thru
this time, especially on Wed ahead of the cold fropa. Quick look at
the 00Z ECMWF shows a farther w track for the sfc lo pres late in
the week, which would result in a longer period of above normal
temps and perhaps some TS.
Sat/Sun...As an upr trof deepens with caa btwn the departing sfc lo
pres wave and hi pres bldg into nw Ontario, h85 temps are progged to
fall as lo as -4 to -6C next weekend. The arrival of this cooler air
over the relatively warm lk waters should result in a lk induced
trof and pcpn in the dvlpg cyc nw flow. Not out of the question some
sn could mix in with the lk effect rain showers over the hier
terrain, but expected near sfc temps appear too warm to support a
fcst of this ptype attm.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 745 AM EDT SUN OCT 2 2016
LIFR conditions at KIWD will give way to VFR conditions by late
morning as daytime heating helps to dissipate the fog. VFR
conditions will prevail at KCMX/KSAW into the evening hrs, though
not out of the question that there could be some MVFR cigs at KSAW
this morning as lingering -shra end. With sfc high pres ridge over
the area tonight, conditions should be favorable for radiation fog
development, more so at KCMX/KSAW where light low-level winds will
have an upslope component. If fog does develop, LIFR conditions seem
likely.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 452 AM EDT SUN OCT 2 2016
Under a weak pressure gradient across Lake Superior, winds will be
mostly under 15kt through Mon. Southeast winds will then increase
Tue/Wed as a cold front approaches. Strongest winds, up to 20-25kt,
will occur Wed over eastern Lake Superior. Cold front will pass
across Lake Superior Wed aftn/evening. W to SW winds up to 15-25kt
should occur on Thu, strongest btwn Isle Royale and the
Keweenaw Peninsula.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...KC
AVIATION...Rolfson
MARINE...Rolfson
Area Forecast Discussion
National Weather Service San Francisco Bay Area
726 AM PDT SUN OCT 2 2016
.SYNOPSIS...An approaching mid/upper level system will result in a
chance of rain showers and a potential thunderstorm or two over the
region today, especially across the San Francisco Bay Area. A second
system will bring another chance of rain showers to much of the
region on Monday along with cooler than average temperatures. Drier
conditions return by Tuesday with a gradual warming trend through
late in the week.
&&
.DISCUSSION...as of 03:53 AM PDT Sunday...Mainly clear skies
prevail over the region this morning with only low clouds showing
up on satellite imagery from Point Reyes southward down the San
Mateo coast. My see patchy to scattered clouds continue to develop
near the coast, yet most inland areas will remain clear ahead of
an approaching mid/upper level system. This system is currently
off of the Pacific Northwest coast this morning and as it
approaches the coast, rain showers continue to develop and move
inland from Humboldt County northward.
The forecast models show rain showers developing just after sunrise
over the North Bay and then spreading southward across the San
Francisco Bay Area late in the morning into the early afternoon as
the system pushes inland to our north. While rainfall amounts are
forecast to be light, generally a few hundredths of an inch or so,
the latest HRRR suggests the potential for locations impacted by the
rain showers to pick up a quick tenth of an inch or two. With that
said, not expecting widespread rainfall amounts greater than one-
tenth of an inch. Showers are then forecast to spread into the South
Bay and across the Santa Cruz Mountains by early afternoon with
similar rainfall amounts likely. May see a few showers extend as far
south as the Monterey Bay Region, yet activity is forecast to
diminish as the upper level system shifts inland. In addition, there
appears to be enough instability associated with this cold upper
level low for the potential for a thunderstorm or two over the
greater San Francisco Bay Area this afternoon. While lingering
showers are not out of the question this evening, the models have
trended toward a drying trend from mid afternoon through tonight as
the upper level feature shifts further inland.
Another system remains on track to quickly follow behind the first
and bring rain showers back to the region on Monday. This system is
forecast to have better moisture availability, yet the mid/upper
level support will weaken as it approaches the coast. Thus, cannot
rule out more widespread rain showers from late Monday morning into
the evening hours as this system quickly sweeps through the region.
Both systems will also bring cooler than average temperatures to the
entire region from Today into Monday along with increased cloud
cover.
Dry weather conditions will return by Tuesday with temperatures
warming slightly, yet still below seasonal averages. A gradual
warming trend will then persist through the remainder of the
upcoming workweek and allow temperatures to rebound back to near
normal for early October.
&&
.AVIATION...as of 5:04 AM PDT Sunday...Expect increasing MVFR
cigs through the morning due to lower level cooling on a moistening
air mass. A weak cool frontal boundary slides east through the
area later today coinciding with the passage of the southernmost
extent of an upper level low. Locally gusty winds observed this
morning over the higher terrain in the East Bay, winds subside
then become gusty again but over a larger part of the Bay Area
this afternoon. Winds subside this evening and become light SE by
Monday morning.
Vicinity of KSFO...Sct-bkn MVFR cig 12z-16z then bkn-ovc020 and
vcsh til 20z. Westerly winds increasing to approx 20 to 30 kt
beginning near 20z today. Drier air arrives later today with VFR
returning in the afternoon. MVFR cig possible again by 11z Monday.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Sct-bkn MVFR cig til 16z then bkn-ovc through
late morning and probably this afternoon as well. Gusty west winds this
afternoon and early evening.
&&
.MARINE...as of 03:53 AM PDT Sunday...A low pressure system over
the eastern Pacific will move southeast over Oregon today and
reach northern Nevada early Monday. The southern extent of this
low will combine with a cool front along the California coast and
pass eastward over the Bay Area today causing gusty winds to
develop over the bays this afternoon and evening. Winds over the
Monterey Bay may also become close to small craft advisory level
this afternoon. Unstable air today will result in a chance of
showers and a slight chance of a thunderstorm. Winds decrease
this evening and become southerly Monday prior to the arrival of
a warm front from the eastern Pacific.
&&
.FIRE WEATHER...as of 07:25 AM PDT Sunday... The core of an upper
low will dsecend into the region today and bring cooler
temperatures, improved humidities, locally breezy onshore winds,
and scattered rain showers across the district today. Isolated
thunderstorms will also be possible this afternoon and evening
primarily around the San Francisco Bay Area and norhtward. Cool
unsettled weather will continue into tomorrow as a second impulse
moved into the region late tomorrow into tomorrow night. Dry
weather will return midweek with near seasonal temperatures
expected.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tday...SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...SF Bay from 12 PM
&&
$$
PUBLIC FORECAST: DRP
AVIATION: Canepa
MARINE: Canepa
Visit us at www.weather.gov/sanfrancisco
Follow us on Facebook and twitter at:
www.Facebook.com/nwsbayarea
www.twitter.com/nwsbayarea
Area Forecast Discussion
National Weather Service Phoenix AZ
858 AM MST SUN OCT 2 2016
.SYNOPSIS...
A low pressure system moving through the Great Basin today and
tonight will bring a cold front through the Desert Southwest.
As the front passes through Arizona, scattered showers and a few
thunderstorms should affect south-central Arizona this afternoon and
evening. Temperatures will dip substantially with highs well below
normal through at least Tuesday. Dry weather will dominate the
weather pattern through the rest of this week while temperatures
gradually climb back toward normal by the end of the week.
&&
.DISCUSSION...
Moisture flux this morning is readily evident in the satellite data
as an expanding field of mid-level clouds from the south. Pockets of
enhanced lift contributing to more organized showers which are
currently moving through the Phoenix area. Rainfall amounts are
upwards of 1/10 of an inch, thus not too much but overall a cloudy
and showery morning. Further west, winds are just starting to pick
up and still expecting a breezy day there. Will be monitoring for any
blowing dust that develops across SE CA/SW AZ this afternoon.
Adjustments to gridded forecast were to raise PoPs/Sky cover in the
moisture plume area for today. Latest SREF and SSEO data support more
widespread precipitation but still looking at amount around 0.1"
(may see areas up to 0.3"). Of course more clouds and gave a strong
nudge on temperatures down to latest HRRR values. Instability values
vary wildly but SREF MLCAPE mean of around 300-400 J/kg seems quite
reasonable, which on the whole isn`t a tremendous amount and with
weak forcing overall allowed us to keep the threat of TS at a slight
chance.
&&
.PREVIOUS DISCUSSION...
The upper trough will weaken as it passes through the Great Basin
tonight while drier northwesterly flow takes over across the Desert
Southwest on Monday. Substantial cooling will take place behind the
cold front with lower desert highs only in the 80s for Monday and
Tuesday. Overnight lows into the 40s is likely across higher terrain
areas with most lower desert locations dipping into the 50s for
Monday night and possibly Tuesday night. Much of the western and
central U.S. will be under the influence of a large trough through at
least the middle of this week and this will keep our temperatures
below normal at least through Thursday. A gradual warming trend will
commence starting Wednesday while upper level ridging begins to work
into the Desert Southwest starting Thursday. The general model
consensus keeps our area dry into next weekend with temperatures
finally back to around normal by Friday or Saturday.
&&
.AVIATION...
South-Central Arizona Including KPHX, KIWA, and KSDL: Tropical
moisture spreading north and into the central deserts this morning,
will lead to scattered showers and isolated storms. Expected
convection to start affecting the terminals after 18z, but new
storms are firing early near Gila Bend so we may see storms into the
greater Phoenix area by mid morning. Expect CIGS to lower to 7-10k
feet during the morning as moisture spreads into the area and
showers develop. Gusty winds over 35 mph possible as well with any
storms today but attm confidence too low to mention in the TAFs. It
is possible that the storms to our southwest will dissipate before
reaching Phoenix as they outrun the area of best instability but we
will need to keep an eye on them and update TAFs as necessary.
Expect that most of the convection in the greater Phoenix area
should push off to the east after 02-03z.
Winds initially southeast, then turning to the south and they should
favor the south through most of the afternoon hours with some
gustiness as well. Winds may briefly try to swing to the southwest
later this afternoon but depending on how significant the showers
(and their outflows) are, winds may be turning back to the southeast
at times.
Southeast California/Southwest Arizona including KIPL and KBLH:
Little if any cloudiness expected next 24 hours but winds will be an
issue, especially at KIPL as west winds will pick up by mid/late
afternoon and gust to near 30kt at times. Similar winds at KBLH but
they should tend to favor the south to southwest. Do not expect
problems with blowing dust and low visibilities but cannot rule out
some lofted dust later today with visibilities briefly down below
5sm. Winds to taper off after 03Z but remaining breezy past midnight.
&&
.FIRE WEATHER...
Tuesday through Saturday:
Relatively dry air moving in from the west to keep skies mainly
clear through the entire period. Winds to remain on the light side
for the most part except for somewhat stronger northwest winds from
Wednesday night into Thursday as a weather disturbance passes by to
the north. Humidities to fall into the high single number-teen range
each day. Overnight recovery will only be fair. Highs in the 80s
across the lower deserts on Tuesday to rise into the low-mid 90s by
Thursday, then hold in that range through Saturday. Overall there
are no significant fire weather concerns through the period.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation will not be needed.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Iniguez/Kuhlman
AVIATION...CB
FIRE WEATHER...Percha/CB
Area Forecast Discussion
National Weather Service Raleigh NC
1055 AM EDT SUN OCT 2 2016
.SYNOPSIS...
A weak surface boundary will remain nearly stationary over
southeastern NC today then dissipate. High pressure will build
southeast into the region and persist through mid-week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1055 AM Sunday...Low clouds and fog across our NE Piedmont and
Northern Coastal Plain zones slow to burn off this morning, being
locked in, in-part, by NE flow north of the sfc trough. Latest HRRR
suggests this could hold on into the mid-day period, perhaps even
early afternoon while slowly burning off around the edges. As such,
may need to make subtle downward tweak to temps across the
aforementioned zones. Outside of the low clouds and fog, remainder
of the forecast remains on track, as described by prev near term
disc below.
prev near term disc as of 330 AM Sunday...A weak sfc trough aligned
north-south along our eastern periphery delineates a moist air mass
with dewpoints in the upper 60s to around 70 versus a drier more
comfortable air mass across the Piedmont where dewpoints were in the
50s to lower 60s. This boundary not expected to change much today.
This will support a narrow ribbon of modest instability and with a
few perturbations crossing the region in the west-sw flow aloft,
will see a few showers skirt northward in vicinity or east of I-95.
Elsewhere, while patches of mid-high level clouds will traverse the
Piedmont later today, the moisture in the entire column appears too
dry to support any showers.
Afternoon temps will be comparable to high temps observed
Saturday,mainly in the 80-85 degree range. Tonight, expect partly to
mostly cloudy skies though any showers occurring at sunset should
dissipate with loss of heating. Overnight temps 59-63.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 330 AM Sunday...
Deep mid/upper level low over the eastern Great Lakes slowly fills
Monday as it drifts across New England. Mean flow over central NC
becomes westerly, advecting a drier stable air mass. This will yield
mostly clear-partly cloudy skies and temperatures close to or
slightly above normal for early October. High temps Monday 77-82.
Min temps Monday night 57-62.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 325 AM SUNDAY...
Surface high centered over New England will ridge down the
Appalachians, while an upper level ridge remains across the East
Coast through Thursday. Expect this period to be mainly dry with
temperatures near normal Tuesday to slightly below normal Wednesday
and Thursday in persistent northeasterly flow.
Models in general agreement with regards to a trough lifting from
the Central Plains to the Northeast Friday through Sunday, though
differences in strength of this feature continue. Given the main
energy with the system will lift well north of the area, expect
little in the way of precipitation associated directly with the
front as it approaches our area. Complicating factor in our sensible
weather during the latter half of the week remains TC Matthew.
Ensemble guidance seems to have clustered toward a solution off the
East Coast, but continues a slowing trend with forward movement.
Given the potential impacts of tropical moisture, slight variability
in track will have considerable ramification on cloud cover and rain
chances in our area, and accordingly, temperatures. Also expect at
least some breeziness with increasing gradient between retreating
high and approaching TC.
Please refer to the National Hurricane Center for the latest
information on Matthew.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
As of 745 AM Sunday...
VFR conditions will persist across most if not all of the Piedmont
through tonight. Across the Sandhills and Coastal Plain, pockets of
MVFR/IFR visibility due to fog and IFR/LIFR ceilings early this morning
will lift/dissipate prior to 14Z.
Beyond 14Z, expect VFR across the entire area. Similar to Saturday
afternoon, there will be a few showers along and east of I-95
though probability of occurrence at KFAY and KRWI is less than
20 percent.
VFR conditions should be dominate through mid week as an area of
high pressure at the surface extends across the region.
The low level east-ne flow around this system will maintain a steady
stream of moisture off the Atlantic. This will support yield brief
periods of sub-VFR conditions early each morning due to fog and/or low
clouds, most probable at KRWI and KFAY, and less of a concern at
KGSO and KINT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...WSS
NEAR TERM...np/WSS
SHORT TERM...WSS
LONG TERM...30
AVIATION...WSS
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
902 AM EDT SUN OCT 2 2016
.UPDATE...
Moisture has increased across the Nature Coast counties and points
northward this morning compared to yesterday morning at this time
as evident in 12Z Raob data and water vapor imagery as remnant
frontal boundary which had been stalled across the central
peninsula drifts northward with weak high pressure north of the
region remaining in control. As for the rest of today ample
moisture combined with daytime heating will support convective
development during the afternoon as the east coast sea breeze
boundary moves west and interacts with the west coast boundary.
The net result will be scattered showers and storms focusing
along and west of the I-75 corridor during the late afternoon and
evening hours which is in line with the latest trends from the
HRRR and other hi-res convective model output.
Similar to yesterday slow storm movement will result in torrential
heavy downpours which may result in some localized flooding of
low lying and poor drainage areas, as well as the ponding of water
on roadways. In addition, strong gusty winds and frequent deadly
lightning strikes will accompany the storms. Current forecast is
on track so a morning update will not be required at this time.
&&
.AVIATION...
Mainly VFR expected although brief MVFR cigs from developing Cu
field may affect the terminals between 14-16Z this morning with
additional MVFR/Local IFR cigs/vsby possible between 21-01Z as
scattered SHRA/TSRA develop during the mid to late afternoon
hours. Have handled SHRA/TSRA chances with VCTS for now, but
brief Tempo groups may become necessary in later forecasts or
amendments. Light and variable winds early this morning will
become west to northwest at 6 to 8 knots at KTPA, KPIE, and KSRQ
terminals after 18Z, otherwise northeast winds at 6 to 8 knots
will prevail with higher gusts in the vicinity of TSRA.
&&
.MARINE...
Surface high pressure to the north of the marine waters will
maintain northeast to east winds around 10 knots with seas of 1 to
2 feet the remainder of today with an onshore sea breeze
component developing along the coast late in the afternoon.
Current forecast is in good shape with no changes expected in the
next forecast issuance around 10 AM this morning.
&&
.TBW Watches/Warnings/Advisories...
FL...Beach Hazards Statement through Monday evening for Coastal
Manatee-Coastal Sarasota.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...57/McMichael
UPPER AIR...09/Rude
DECISION SUPPORT...74/Wynn
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
208 PM AKDT SUN OCT 2 2016
.DISCUSSION...
Morning 12Z 500 dam analysis shows strong 560 dam high centered
over the Beaufort Sea. Broad upper low pressure at 519 dam was
seen centered over eastern Siberia, with troughing extending to
the east southeast with the trough axis extending from
Beringovsky to Gambell to Kodiak, with a 544 dam low centered
over Kodiak Island. A 538 dam low was seen over northwest Canada
over the Yukon/NW Territories boarder.
At the surface, morning analysis shows 979 mb low now centered
over the southern Chukotsk Peninsula, with troughing extending
eastward into the Alaska mainland. An ill-defined frontal system
extends from Point Hope to Galena to Anchorage. A ridge of high
pressure extends from the Siberian arctic southeastward across
the Beaufort Sea into the Canadian Archipelago. Another area of
low pressure was over the North Pacific
The 12Z suite of deterministic models in fair agreement over the
larger scale upper air pattern through about 96 hours, before
they begin to diverge on the timing and placement of the
positioning of the existing ridge. The upper low in eastern Siberia
will retreat further westward, with a shortwave trough to swing
around the low and move into the Yukon Delta tonight. This feature
combined with the decaying weather front over the western part of
the state will bring showers to the southwestern half of the state
through Monday, before precipitation chances begin to dwindle
significantly beginning Tuesday as the upper ridge reasserts
itself into the state. Another short wave trough will move into
the western Bering by Tuesday morning, then swing northward into
the Chukotsk Peninsula on Wednesday. Another weakening weather
front will move up the Bering Sea Tuesday and Tuesday night, which
will only bring very low chances of rain for the Yukon Delta and
St Lawrence Island. Other than the showery weather expected for
mainly the western half of the state into Tuesday, the building
ridge of high pressure will bring mainly fair weather to the North
Slope and central and eastern Interior for the upcoming work week.
Falling H85 temps between 0 to -4 will promote more seasonal
temperatures compared to what has been seen over the weekend.
Still watching the situation in the Bering sea for the latter part
of the work week. A strong piece of upper level energy will move
out of east Asia into the western Aleutians, to form deep low
pressure there at or below 970 mb per the current 12Z guidance.
As this low rotates northward toward the Gulf of Anadyr, recurving
typhoon Chaba, extratropical by this time, enters the western
Aleutians to ultimately merge with Bering Sea low. Exact track and
placement of these features remains uncertain given the lack of
run to run consistency with mainly the GFS, but more consistent
ECMWF/GEM and the EC/GEFS means continue to suggest the low to
remain to the south of our marine forecast area, promoting
offshore flow for southwest Alaska and little to no surge
problems. Biggest threat at this time appears to be just strong
wind and wave action for waters south of the Seward Peninsula.
North Slope: Area of fog and stratus has been very stubborn to
push out of the Wainwright and Barrow area this afternoon. A brief
period of clearing still remains possible late this afternoon and
evening as subtle diurnal mixing and dry air advection from the
southeast helps to erode the eastern edge of this fog bank. High
resolution HRRR guidance suggests fog moving back into the arctic
coast tonight from the north, which lends some support from trends
from current visible and fog satellite products. More bouts of
stratus and fog remain possible this week under surface high
pressure and very light onshore flow. A small craft advisory
remains for marine zone 245 as Brooks Range leeside trough
diminishes and high pressure builds into the eastern Beaufort Sea.
Coastal Hazard Potential Days 3 and 4...None.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory for PKZ210-PKZ245.
&&
$$
NTS OCT 16
Area Forecast Discussion
National Weather Service Albany NY
411 PM EDT SUN OCT 2 2016
.SYNOPSIS...
An upper level low will continue to bring mostly cloudy and cool
conditions with isolated to scattered showers and thunderstorms
through Monday. The upper low will move east of the region Monday
night. High pressure will bring fair and dry weather for Tuesday
into Wednesday with temperatures trending above normal.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Deep cloudiness and moisture feeding north through eastern NY and
western New England but some clearing in western and parts of
central NY. The clearing has stopped its progress as maritime low
level flow in eastern NY and western New England is providing
moisture and isentropic lift north of a low level dew point
boundary. Some very slow and gradual erosion seen in eastern PA
and central NY, suggesting that as the upper low and an axis of
subsidence or dry slotting around the periphery of the upper low
drifts east, it eventually supports some break up of the clouds
perhaps into the central Mohawk Valley, southern Adirondacks and
eastern Catskills before daybreak. There could be some patchy
light rain and drizzle this evening in eastern NY until the dry
slotting and subsidence breaks up some of the clouds.
Line of convection in western/central NY making steady progress
east. The HRRR suggests the convection in western/central NY
tracks east and affects the western Mohawk Valley and southern
Adirondacks this evening, perhaps the Lake George and Saratoga
regions around or after midnight if it holds together. Some
isolated showers or thunderstorms could extend southward into the
Eastern Catskills, Hudson Valley and Capital District. Lows
tonight around 50 to mid 50s most areas.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Upper low tracks across our region Monday and there should be
intervals of clouds and sun by late morning, then more clouds than
sun in the afternoon as convective temperatures are reached under
the upper cold pool. There will be scattered showers and
thunderstorms, perhaps with some small hail and locally heavy rain due
to the cold air aloft. Highs Monday in the mid 60s to around 70
but some lower 60s northern areas.
Any lingering showers exit Monday night and clouds exit through
Tuesday morning as the upper low exits, weakens and gets forced
south and east into the Atlantic. Upper ridging builds in from the
Great Lakes and southern Canada with sunny weather expected later
Tuesday morning through Wednesday. Boundary layer temperatures
cool a bit and winds are expected to be light proximate to the
center of the low level ridging. High temperatures Tuesday in the
mid to upper 60s and on Wednesday in the upper 60s to lower 70s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A deep-layered ridge of high pressure centered over Maine and Nova
Scotia, and ridging down the East Coast, should keep our weather
fair Wednesday night through Friday, with temperatures averaging
slightly above normal. Expect high temperatures to range from the
60s to lower 70s, with overnight lows mainly in the 40s to lower
50s. Biggest challenge through early Friday will likely be potential
for nighttime fog formation, and morning dissipation times for any
fog/low clouds. Also low temperatures may be around 5F colder than
currently forecast if subsidence under high pressure mixes dry air
to surface. This drier air combined with longer October nights and
light winds, would make for ideal radiational cooling and min temps
could be lower.
For Saturday-Sunday, the forecast will entirely depend on the
ultimate track of Matthew, a cold front approaching from the west,
and any possible northern stream interactions with Matthew and
associated tropical moisture. At this time, Matthew still looks to
remain south/southeast of Cape Hatteras, NC through Sunday, but due
to uncertainty lingering, have indicated chc pops for showers during
this period, mainly due to the possible cold front approaching from
the west. However, there is a possibility that with Matthew and
deeper tropical moisture remaining well to our southeast, moisture
availability could be limited with the front, leading to a drier
scenario for next weekend. Please refer to the National Hurricane
Center, as well as the Weather Prediction Center, for more specific
details related to the track/evolution of Matthew and potential
interactions of Matthew with tropical moisture/northern stream
systems.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
Combination of MVFR/IFR CIGS across the region as this should
prevail through the remainder of the afternoon and evening hours.
Not much showing up on the nearby radar scans, however, regional
radar views show a line of convection across western NY/PA that
continues to track northeast. Per the latest HRRR, seems these
showers may have the opportunity to impact KGFL-KALB-KPSF later
this evening into the early overnight period as we will place
a PROB30 at this time. Otherwise, mainly IFR conditions overnight
with CIGS and the VIS coming down as well.
Winds will generally be variable in direction at speeds 5kts or
less (even dropping to a period of calm overnight).
Outlook...
Monday Night: Low Operational Impact. Slight Chance of SHRA.
Tuesday to Friday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
An upper level low will continue to bring mostly cloudy and cool
conditions with isolated to scattered showers and thunderstorms
through Monday. The upper low will move east of the region Monday
night. High pressure will bring fair and dry weather for Tuesday
into Wednesday with temperatures trending above normal.
RH values through Tuesday afternoon are expected to be greater
than 55 percent with near 100 percent tonight and Monday night.
Winds will become north to northwest at less than 15 mph tonight,
becoming north Monday. Winds become east to northeast at less
than 15 mph Monday night and Tuesday.
&&
.HYDROLOGY...
No hydro problems in the Albany Hydro Service Area /HSA/ the next
5 days ending Thursday.
The latest US Drought Monitor continues to show drought conditions
across much of the region. Precipitation departures this calendar year
have been 3 to 12 inches below normal, with the greatest
departures across southeastern parts of the HSA. As a result,
streamflow and ground water levels have been running below normal.
Some additional rainfall is expected tonight into Monday
associated with a slow moving upper level low drifting across the
area. Most locations will see an additional tenth to half inch of
rainfall through Monday.
Dry weather will return for Tuesday into Thursday.
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...NAS
NEAR TERM...NAS
SHORT TERM...NAS
LONG TERM...KL
AVIATION...BGM
FIRE WEATHER...NAS
HYDROLOGY...NAS
Area Forecast Discussion
National Weather Service State College PA
625 PM EDT Sun Oct 2 2016
.SYNOPSIS...
An upper low will drift east across the southern peninsula of
Ontario today...keeping a deep-moist southerly flow over the
region. A ridge of high pressure will build east into Pennsylvania
behind this system Monday, and will likely remain over the area
through the middle, and perhaps even the end of the work week
bringing mainly dry and slightly milder conditions across Central
Pennsylvania.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Been watching showers and isolated thunderstorms on the radar
since I came in at 3 PM. Isolated thunder across the north.
Starting to see stronger returns now west of Harrisburg.
Adjusted pops, weather, and clouds some in the grids for this
evening and some time periods overnight.
Earlier discussion below.
As the upper low begins to kick out to the east, the influence of
at least one shortwave can be seen with an area of scattered
showers affecting about the western half of the CWA. The RAP meso
anal shows some modest instability with mid level lapse rates in
excess of 6C/km over the NWRN 1/3 portion of the region and a few
hundred Joules of Cape indicated area-wide. Visible shots are
showing some breaks in the overcast so it`s still possible to see
a taller tower cause some thunder and lightning.
Partial clearing can be expected tonight as the showers move east
and dissipate. Clouds will hang in longest over the north but
overall a drying trend will develop as the upper low kicks out to
the north and a westerly flow sets in.
Lows tonight will vary from near 50 over the high terrain of the
north and west to the mid 50s in the SE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
Adjusted cloud cover early on during the day on Monday.
Earlier discussion below.
Weak high pressure will build slowly down from the north Monday.
However cyclonic flow and cold air aloft should set up a fair
amount of self-destruct sunshine, especially over the northern
half of the forecast area. While a shower cannot be ruled out, I
used the more optimistic model blended pops that show little more
than an isolated shower early.
Highs will range from the mid 60s north to lower 70s over the
south.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Improving weather expected early in the week as upper ridging
builds northward over the region in the wake of departing upper
troffing that has controlled the weather for the last several
days. Abundant sunshine not expected however, as surface high
pushing the cooler air our way slides off the New England coast
midweek, and creates an easterly low level flow once again with a
long fetch of moisture aimed at southern PA. How extensive the
cloud coverage will be and if it will be sufficient to generate
drizzle of even rain is still a question. If part this will depend
on the northward influence of Hurricane Matthew.
The 00Z GFS brings a potent Matthew across the Western Bahamas
then has it paralleling the SE U.S. and Carolina coast late in the
week...before projecting it to get captured by a deepening upper
trough and accelerating north into Long Island next Sat/Sat night.
GEFS has roughly the same track, but as expected becomes more
diffuse through time with the location and intensity of the
storm`s center just off the East Coast.
The 30/12z operational ECMWF parked the storm over or just to the
north of the Bahamas for a prolonged period during the middle to
latter part of the upcoming week, which was a low confidence
solution.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Most spots across Central Pa should remain VFR this evening.
However, widely scattered showers could produce a brief reduction
in some locations. Main aviation concern will come late tonight,
as moist upsloping flow likely results in low cigs along the spine
of the Appalachians from KBFD south to KJST, while clearing skies
and a calm wind is likely to promote areas of fog across the
eastern part of the state. A blend of latest SREF, HRRR and
downscaled NAM support likely IFR conditions by around midnight at
most Central Pa airfields. Exception may be KUNV and KAOO, where
enough of a breeze could keep sig vis reductions at bay.
Diurnal heating/mixing within deepening boundary layer will cause
low cigs and fog to lift by late morning. All guidance pointing
toward widespread VFR conds and light wind for Monday afternoon.
Outlook...
Tue...AM visibility reductions possible in patchy fog, then VFR.
Wed-Fri..Mainly VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte/Martin
SHORT TERM...Lambert/Martin
LONG TERM...Lambert/Gartner
AVIATION...Fitzgerald/La Corte
Area Forecast Discussion
National Weather Service Huntsville AL
249 PM CDT Sun Oct 2 2016
.NEAR TERM...(Tonight)
Issued at 245 CDT Sun Oct 2 2016
Water vapor imagery and RAP H5 analysis showed an upper low
departing the Great Lakes region to the NE, with a building ridge
across much of the Central CONUS. Another upper low was coming
ashore in the PAC NW. At the sfc, high pressure remained in control
of the region, with light northerly winds across the TN Valley.
Tonight will be a near-repeat of last night without much of a
significant pattern change across the area. The scattered CU that
developed across the area today will subside with sunset this
evening, leaving only a few mid-level clouds overhead overnight.
Some patchy fog will be possible by sunrise as well, mainly in the
sheltered valley locations of NE AL and Srn Middle TN, but this
should be rather patchy in nature. Morning lows will be a few
degrees warmer than this morning, bottoming out in the lower to
middle 50s (as opposed to the middle/upper 40s to lower 50s).
.SHORT TERM...(Monday through Tuesday)
Issued at 245 PM CDT Sun Oct 2 2016
The surface high will shift east and southward slightly Monday
through Tuesday morning. Models do show an upper level trough (some
upper level energy) in the Gulf of Mexico edging northward during
this period. Models hint at a weak inverted trough axis forming
northward from that into Georgia or Alabama. As the high pushes
further east and a fairly strong upper level trough pushes into the
central U.S., more established southerly flow develops over northern
Alabama and Southern Middle Tennessee. This could produce some
additional cloud cover and maybe some isolated showers near I-65 by
Tuesday. The depth of moisture should still be too meager for more
than isolated showers.
.LONG TERM...(Tuesday night through Saturday)
Issued at 245 PM CDT Sun Oct 2 2016
Also by Tuesday, Hurricane Matthew should have moved north and be
near the coast of Puerto Rico. The high shifting off into the
western Atlantic should keep it moving very slowly. In fact, it looks
like it will keep Hurricane Matthew off the eastern coast of Florida
Tuesday night through Friday. This should enhance ridging aloft
Wednesday through Friday over northern Alabama and keep the front and
precipitation to our west through Friday. Models are in fairly good
agreement with this type of solution. However, increasing southerly
flow should allow morning lows to warm into the mid 50s to lower 60s.
Also, high temperatures due to the strong subsidence aloft will climb
back into the mid to upper 80s, about 5 to 10 degrees above normal.
Models move the front into the area sometime between Friday night
and Saturday morning. Little lift due to the weakening nature of the
front and very strong subsidence aloft should give us little chance
of any rainfall. The main impacts of this front will be a return to
near normal temperatures in the mid to upper 70s and cooler overnight
lows dropping back into the upper 40s to lower 50s.
&&
.AVIATION...
For 18Z TAFs: VFR conds will prevail thru the TAF period at both
terminals. SCT/BKN clouds arnd 4-5kft will linger through sunset this
evening, dissipating with just mid-level clouds streaming overhead
overnight. Patchy fog will be possible by sunrise Monday morning, but
is expected to remain to the east of both KHSV and KMSL. Lower-
level CU will redevelop tomorrow afternoon, but no degradation in
flight conditions are expected.
12
&&
.PRELIMINARY POINT TEMPS/POPS...
Huntsville 54 84 57 87 / 0 0 0 10
Shoals 54 83 56 87 / 0 0 0 0
Vinemont 54 83 55 85 / 0 0 0 10
Fayetteville 53 82 56 84 / 0 0 0 10
Albertville 54 83 57 84 / 0 0 0 20
Fort Payne 54 83 57 84 / 0 0 0 10
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Wilmington OH
324 PM EDT Sun Oct 2 2016
.SYNOPSIS...
An upper low across the eastern Great Lakes will help spark a few
showers this afternoon. The low will move into New England
by Monday. High pressure will then build into the region, leading
to dry conditions and a warming trend through the middle of the
week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Upper low resides across the Eastern Great Lakes this afternoon,
while a trough extends southwest from the low into central
Kentucky. Weak convergence near the trough will promote a few
showers through the afternoon across portions of Ohio and northern
Kentucky, mainly east of Interstate 71. This is depicted well by
most guidance including recent runs of the HRRR and RAP.
Showers will move to the east through the afternoon, and should
dissipate by early evening. There may be partial clearing during
the mid to late evening, but models indicate sufficient low level
moisture where stratus is likely to form again overnight along
with patches of fog. Lows will be close to the dewpoints...in the
lower to mid 50s.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Upper low opens up, and moves across New England Monday.
Meanwhile, flow will become more anticyclonic across the Ohio
Valley for the early week period.
CWA is likely to start Monday with cloudy skies and patchy fog,
but some sunshine (more than recent days) is expected during the
afternoon as high pressure builds in, with high temperatures in
the lower 70s.
High pressure remains in control Monday night through Tuesday
night. Result will be mostly clear skies at night/mostly sunny
skies during the day. Under high pressure, mostly clear skies and
light winds may promote patchy fog development both Monday night
and Tuesday night, particularly in fog prone areas.
For temperatures, a warming trend will also be noticed on Tuesday
as the center of the high will be to the east. High temperatures
are expected to rise into the mid and upper 70s for Tuesday.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Ridge axis to the east of the area at the surface and aloft will
keep warm and dry conditions across the region for the early part of
the period. A trough will emerge out of the Plains and cross the
Ohio Valley and Great Lakes Friday into Saturday. This will result
in a cold front crossing the area late Friday into Friday night.
Some post-frontal showers will be possible. It will dry out again
for the weekend with temperatures dropping to or slightly below
normal.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Most TAF sites are VFR as an upper level low continues to eject
northeast of the area. At the surface there is a weak trough axis
or area of convergence which has helped some weak showers to form.
Instability remains extremely limited so am expecting no thunder
(ML CAPE <200 J/kg). These weak showers will then come to an end
this evening as the sun goes down and the trough axis pushes east.
Overnight into Monday morning, forecast soundings on both the GFS
and NAM again indicate the potential for fog thanks to favorable
vertical humidity profiles and weak winds. The main uncertainty is
how much cloud cover will be around. Forecast soundings on both
the GFS and NAM hint at some clearing only to have low cigs and
fog form. If an MVFR deck forms this will inhibit fog formation.
Most high res guidance is in between these solutions. Showing
IFR/MVFR cig and vsby restrictions. Think this is the most likely
solution.
During the day Monday, GFS and NAM forecast soundings both show a
persistent MVFR deck hanging around until the end of the issuance.
Looking at what has happened today and high res guidance think
this is to pessimistic. Have trended all TAF sites VFR by the end
of the issuance.
OUTLOOK...No impacts to aviation expected.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...BPP
NEAR TERM...BPP
SHORT TERM...BPP
LONG TERM...
AVIATION...Haines
Area Forecast Discussion
National Weather Service Marquette MI
327 PM EDT Sun Oct 2 2016
.SHORT TERM...(This evening through Monday)
Issued at 327 PM EDT SUN OCT 2 2016
Water vapor imagery and RAP analysis show a mid level low over the
Lower Great Lakes region. NW fringe of the deep layer
forcing/moisture associated with this feature was still generating a
few shra across eastern Lake Superior and far eastern Upper MI this
afternoon. The rest of the cwa has remained dry under influence of
sfc ridge whose axis is centered just west of Upper Mi.
Sfc high pres ridge will shift over the fcst area tonight, providing
a quiet night. While some lingering clouds over the e along with a
stronger ene wind just off the sfc should reduce the potential of
fog development in that area tonight, mostly clear skies and lighter
winds under ridge axis over the w and central will lead to some fog
development tonight as temps fall back blo the expected minimum dew
point readings from this afternoon. Developing upslope/onshore
easterly wind could aid fog formation over the Keweenaw. Min temps
may slip just blo 40F over the interior w tonight under best
radiational cooling. Highest readings will be along Lake Superior
where temps should mostly stay aoa 50F.
Diurnal heating will burn off fog by late morning and prominent
ridging over the region will result in a pleasant day on Monday
under mostly sunny skies. Forecast mixing to near 875 mb should
yield high temps generally in the mid to upper 60s with warmest
readings for areas along Lake Superior favored by downsloping se
winds.
.LONG TERM...(Monday night through Sunday)
Issued at 324 PM EDT SUN OCT 2 2016
Most impactful weather in the long term is fog (possibly dense) Mon
night into Tue morning. Dew points will increase into the 50s to
around 60 Mon night before coming back down Wed night, which should
lead to fog mainly over central and eastern portions of Upper MI
where upslope SSE flow and moisture off Lake michigan will be
present.
A closed low will move well NW of the CWA in the middle of the week,
which will drag upper and SFC troughs and a SFC cold front through
the CWA on Wed. This results in a quick round of showers and
possibly a few thunderstorms mainly between 12Z Wed and 00Z Thu.
Moisture cuts out behind the cold front, but the warmer than average
airmass sticks around until after a more potent upper wave and SFC
reflection move through sometime late in the week (models disagree
on timing). Widespread rain would result as the system passes.
Along and behind the upper trough, models have 850mb temps dropping
below 0C, possibly as low as -5C as the GFS suggests. However,
models disagree on magnitude and duration of the colder air and the
wind directions. Could see some snow flakes over higher terrain
areas overnight Fri and/or Sat night, but it doesn`t look like
enough to accumulate at this point.
Utilized blends for much of the forecast.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 251 PM EDT SUN OCT 2 2016
With sfc high pres ridge over the area tonight, conditions should be
favorable for radiation fog development, more so at KCMX/KSAW where
light low-level winds will have an upslope component. If fog does
develop, LIFR conditions seem likely. Expect improvement to VFR by
late Monday morning with diurnal heating/mixing.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 327 PM EDT SUN OCT 2 2016
Under a weak pressure gradient across Lake Superior, winds will be
mostly under 15kt through Mon. Southeast winds will then increase
Tue/Wed as a cold front approaches. Strongest winds, up to 20-25kt,
will occur Wed over eastern Lake Superior. Cold front will pass
across Lake Superior Wed aftn/evening. W to SW winds up to 15-25kt
should occur Wed night into Thu, strongest between Isle Royale and
the Keweenaw Peninsula.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Voss
LONG TERM...Titus
AVIATION...Voss
MARINE...Voss
Area Forecast Discussion
National Weather Service Reno NV
255 PM PDT Sun Oct 2 2016
.SYNOPSIS...
A cold trough moves into the West Coast today bringing gusty winds
and temperatures well below seasonal averages along with the threat
for lower valley freezes through mid-week. Valley rain and mountain
snow showers are expected tonight and Monday night, with light
snow accumulations possible over the Sierra passes this evening.
Temperatures will warm back to near average by Friday.
&&
.SHORT TERM...
The main forecast concerns today are winds and humidities through
this evening (mainly along/south of I-80), possible slick conditions
over northern Sierra passes this evening, and sub-freezing temperatures
for the lower valleys of western Nevada in the next few nights.
Low pressure is dropping into northern California this afternoon
and a wind shift has moved into western Nevada. However, little
change in temperature or moisture has accompanied the shift so
believe the main surface front to be with a band of precipitation
(and solid wind shift/temperature change) nearing the northern
Sierra early this afternoon. Some light rain has moved into Lassen
and Plumas Counties this afternoon with a wet road indicated by
web cams over Fredonyer Summit. Wind-wise, gusts between 25 and 35
mph (locally 40-45 mph) are widespread for eastern California and
far western Nevada this afternoon. These winds should continue
well into evening. However, humidities should begin to recover
(and already have north of Tahoe in CA) as colder air filters into
the region. For more, see the fire weather discussion below.
Precipitation-wise, the initial frontal band of precipitation
should go through quickly. Because precipitation is moving into
the northern Sierra in the daytime, roads should remain mostly wet
even over the crest (where snow will fall) due to well above
freezing road surfaces. The main concern is between about sunset
and 11 PM in the northern Sierra (down to about Ebbetts Pass) when
widespread snow showers are expected under the upper low. The HRRR
model continues to show locally heavy convective showers.
However, it is hard to predict where narrow heavier bands will
form and threaten slushy accumulations over Tahoe/Alpine County
passes. Motorists should be prepared for slow travel over I-80, US
50, and for Mt Rose highway if they must wait until after dark to
travel.
Showers should taper off rapidly by midnight in the northern Sierra
as the upper trough axis passes to the east. Any slushy conditions
in the northern Sierra should abate quickly once showers taper off.
Outside of the northern Sierra, only a brief shot at some light
showers is expected tonight mainly just ahead of the trough axis.
Turning to freezing temperature concerns, the latest HRRR is casting
doubt that winds will calm down sufficiently or skies will remain
clear long enough for a widespread freeze (locally defined as 30
degrees or less) in western Nevada tonight. Still, with the colder
air filtering in valley temperatures should fall into the 30s to
around 40 even if they remain mixed so it won`t take much for a
dip to 30 degrees or so for a couple hours. Therefore, the freeze
warning for suburban and outlying valleys of far western NV will
remain up for late tonight and Monday morning.
Monday, a period of warm air advection/isentropic ascent is expected
Monday afternoon and evening. This will bring the threat for some
light showers, with snow levels rising generally above 7000 feet
by late in the day. No road impacts are expected as the showers
should be fairly light and the time of day is not ideal for road
accumulations.
Another brush-by system could bring a few more showers north of
I-80 Tuesday. However, the main focus will be late Tuesday night
and Wednesday morning temperatures for the lower valleys of
northeast California and western Nevada. Tuesday morning looks a
bit mixed up with a moist low level atmosphere so widespread
freezing temperatures are not expected. Wednesday, and especially
Thursday morning is a different story as drier air begins to
filter into the area with slackening winds. At this time, it looks
like Wednesday and/or Thursday morning will finally bring
widespread below freezing temperatures to many areas of western
Nevada. Snyder
.LONG TERM...Thursday through Sunday...
The long-term forecast calls for dry conditions Thursday through
Sunday with the storm track north of the Oregon border. Model
simulations do show weak impulses crossing the Sierra and western NV
from west to east which could create periods of mid-to-high level
cloudiness, mainly north of highway 50. There is a chance one of
these impulses could bring a period of showers north of Susanville,
but overall moisture looks to be quite limited so we maintained the
chances for precipitation less than 15%. Some model simulations
advertise a Pacific trough approaching the west coast Sunday which
could bring an increase in moisture to the Sierra by Sunday night (a
week from tonight), but this is a minority opinion.
A slow warming trend of afternoon highs is forecast Thursday through
Saturday or Sunday, although cloud thickness is a variable that could
possibly temper that trend. Highs for Saturday and Sunday could warm
into the mid to upper 70s in western NV and upper 60s to low 70s for
Sierra communities. JCM
&&
.AVIATION...
A cold front passage is creating gusty west winds through this
evening with peak gusts 30-40 kts from the lee of the Sierra out
into western Nevada and far northeast California. Expect Sierra
ridges to see gusts up to 60 kts through this evening along with
moderate turbulence near and in the lee of the Sierra.
A mix of rain and snow this evening could bring an inch or so of
slushy accumulation to KTRK and KTVL. Cigs/vsbys into the MVFR/IFR
range in the northern Sierra and northeast California are also
expected through this evening. To the east and south rain and snow
showers will be more scattered in nature but with IFR conditions
possible near the Sierra crest in Mono county. VFR conditions are
likely in western Nevada...but with some mountain obscurations.
Snow in the Sierra will taper off to showers by midnight. Showers
could linger into Monday as well and possibly Monday night north of
I-80. Ceilings should improve Monday and winds will be lighter. Light
precipitation is possible north of I-80 Tuesday and
Wednesday...but conditions should be no worse than MVFR. 11/20
&&
.FIRE WEATHER...
Gusty winds will continue into the early evening hours, as a cold
front pushes through the region. Red Flag Warning remains in place
for Mono-Alpine-Southern Lyon and Mineral Counties through 6PM.
Moisture is increasing to the north of Reno-Tahoe, with precipitation
and clouds already moving into the Truckee-Tahoe area. Wind gusts
of 35-45 mph have been observed so far this afternoon for all
areas, but the strongest winds have been mainly south of Carson
City and down to Mammoth Lakes. Drier conditions exist south of
Carson City with humidity in the low teens and even down to near
5% as you get near Mammoth Lakes/Benton/Bishop. Areas of critical
conditions have also expanded slightly further north to near
Minden/Gardnerville where firefighters are responding to a new
wildfire near Dresslerville and Highway 395.
Low pressure moving into northern CA/NV today will bring moisture
and showers into the Northern Sierra and Lake Tahoe Basin through
this evening. Snow levels will drop to around 5500-6000 feet this
evening, bringing light snow accumulations of up to a few inches to
the Northern Sierra above 7000 feet (mainly north of Ebbetts Pass
all the way north to Lassen Park and the Warner Mountains.
Breezy northwest flow will continue over the next couple days with
temperatures slowly warming each day. Lighter winds are expected by
Wednesday and Thursday as high pressure builds back over the region.
Hoon
&&
.REV Watches/Warnings/Advisories...
NV...Freeze Warning from 2 AM to 8 AM PDT Monday NVZ003.
Red Flag Warning until 6 PM PDT this evening NVZ459.
Lake Wind Advisory until 8 PM PDT this evening for Lake Tahoe in
NVZ002.
Lake Wind Advisory until 8 PM PDT this evening for Pyramid Lake
in NVZ004.
CA...Freeze Warning from 2 AM to 8 AM PDT Monday CAZ071.
Red Flag Warning until 6 PM PDT this evening CAZ273.
Lake Wind Advisory until 8 PM PDT this evening for Lake Tahoe in
CAZ072.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno