Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/07/16
See below for an updated aviation forecast discussion.
&&
.SHORT TERM...(This Evening through Saturday Night)
Issued at 330 PM CDT THU OCT 6 2016
Light rain continues to affect southern and eastern portions of the
CWA, with more activity heading north-northeast out of the FSD CWA.
Models handling this system fairly well and will continue to see
rain stream up the southern and eastern counties into the evening
hours. Main issue for the overnight period is the temperature
forecast. Rather difficult forecast overnight because clouds will be
across the area well into the evening hours. Although, there will be
clearing from west to east later tonight. Models do try to bring
down some more cloud cover from the northwest as well. So, not a lot
of confidence in temperature forecast tonight in that they have the
potential to be too cold in places where clouds linger the longest.
It certainly won`t take much clearing though for temps to tumble
fast given the cold air mass in place. Generally went with upper 20s
to lower 30s across the CWA, which lead to the issuance of
frost/freeze headlines.
Friday will be dry but continued cool with highs in the upper 40s to
mid 50s. Will once again be looking at frost/freeze potential late
Friday night into Saturday morning as the surface high lingers over
the area. Cool temperatures once again forecast on Saturday with
highs in the 50s and 60s. Warmer air finally returns to the region
to start off the extended period.
.LONG TERM...(Sunday through Thursday)
Issued at 330 PM CDT THU OCT 6 2016
Nearly zonal mid level flow will be dominant over the area until
around mid week, with a weak shortwave trough tracking across the
area Tuesday and Tuesday night. The flow becomes zonal again for a
brief time, then a stronger shortwave looks to affect the region
late in the period.
At the surface, the region will be between high pressure to the east
and low pressure to the west on Sunday. Dry conditions are expected
until the low finally works its way east and across the Northern
Plains, with its associated frontal boundary moving through Monday
night. May see some post frontal rain showers late Monday night into
Tuesday, mainly across the northern CWA. High pressure moves in and
brings a return to dry conditions until another low pressure system
moves in from the west on Thursday.
With somewhat warm southerly flow over the area during the early
part of the period, will see above normal temperatures with highs in
the mid 60s and 70s Sunday and Monday. Cooler air then moves in
behind the front with highs in the 50s to mid 60s Monday and Tuesday
before a return to warmer highs in the 60s to lower 70s on Thursday.
Overnight lows will be mainly in the 40s, but will see lows down
into the 30s in parts of the area Tuesday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 620 PM CDT THU OCT 6 2016
mvfr cigs/visbies are sneaking up into the KATY terminal this
hour while light to moderate rain continues. Will prolly see a
brush with sub-vfr for a few more hours early this evening at
KATY before rain begins to diminish and shift east into minnesota.
Elsewhere, vfr conditions should continue for most of the next 12
to 24 hours at KPIR/KMBG and KABR. Short range model guidance
continues to hint at the vfr/mvfr low clouds up over nern Montana
and nwrn North Dakota dropping southeast toward KMBG and KABR
Friday morning. Will continue to monitor.
&&
.ABR Watches/Warnings/Advisories...
SD...Freeze Warning from 1 AM CDT /midnight MDT/ to 10 AM CDT /9 AM
MDT/ Friday for SDZ003>007-009>011-015>020-022-033>037-045-
048-051.
Frost Advisory from 3 AM to 10 AM CDT Friday for SDZ008-021-023.
MN...Frost Advisory from 3 AM to 10 AM CDT Friday for MNZ039-046.
&&
$$
UPDATE...Dorn
SHORT TERM...TMT
LONG TERM...Parkin
AVIATION...Dorn
Area Forecast Discussion
National Weather Service State College PA
1153 PM EDT Thu Oct 6 2016
.SYNOPSIS...
A deepening 500 hPa trough and accompanying front will bring rain
to the State overnight Friday into Saturday. Cooler drier weather
is expected into early next week. A weak 500 hPa ridge moves back
in by the middle of next week ahead of another approaching trough.
Another cool air mass could enter the region later in the week.
Hurricane Matthew will remain far to our south and not directly
impact our weather.
&&
.NEAR TERM /UNTIL 9 AM FRIDAY MORNING/...
Minor changes to grids for fog and low clouds creeping in from the
south. Nudged temperatures a tad. The dew points are bit higher
than last night but should be chilly night mainly in the 40s to
lower 40s across the region.
Areas in central mountains and southwest will still be in the
thick of the low clouds and valley fog by 9 AM.
&&
.SHORT TERM /9 AM FRIDAY MORNING THROUGH SATURDAY/...
Morning clouds and fog should lift before 11-12 AM in most
locations. A good start to the day.
The easterly flow over southern Pennsylvania will enhance during
the day Friday as the high to our northeast moves over the western
Atlantic and the gradient between the high and the along the
Florida coast becomes stronger.
The easterly flow will enhance the upslope during the late morning
and early afternoon hours along the southern tier. The HRRR does
not go far enough out to see the afternoon impacts. But the RAP
does and clearly it will become cloudy near the Maryland border
and the upslope could produce drizzle in the southwest mountains
in the later afternoon and evening.
Most models imply the rainfall holds of in the southwest until the
evening. Then the probability of rainfall begins to increase.
Best chance of rain will be overnight into Saturday morning.
Increasing POPS overnight. The new 18Z GEFS shows the rain moving
southwest to northeast across the State in the 0000 UTC to 1200
UTC timeframe Friday night into Saturday morning.
By early morning Saturday there should be a good band of rain
across central Pennsylvania poised to move rapidly eastward. Our
forecast is in 3-hour chunks to show the rapid west to east
progression with morning POP maximum in west and early afternoon
POP max in the east. By evening most areas should be pretty much
rain free with cooler air working into the region.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Passage of the cold front Saturday afternoon and evening cold
will bring the coolest temperatures of the season, with
temperatures across all of PA dropping into the 40s, or cooler,
next Monday and Tuesday morning. The upper ridge is forecast to
build slowly back through next week ahead of a deepening upper
trof over north central Canada. So the cool down will be short
lived and dry weather will return for much of next week.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
Clear skies and a calm wind beneath high pressure ridge will cause
fog to form late tonight, similar to what occurred last night.
Blend of latest SREF, HREF, LAMP, downscaled NAM and persistence
all point toward IFR/LIFR vsbys late tonight, beginning as early
as around 04Z at KUNV and KIPT, around 06Z at KBFD/KAOO and
perhaps KMDT/KLNS between 06Z-09Z. The RIDGE TOP location of KJST
is unfavorable for radiation fog. However, a light sse flow could
potentially yield some low cigs in the 06Z-13Z time frame. Model
soundings indicate fog and low cigs will mix out to VFR in most
locations between 14Z-16Z, with good flying conds for the rest of
the day.
Outlook...
Sat...Showers reduced cigs, mainly in the morning.
Sun...No sig wx expected.
Mon-Tue...Patchy AM fog possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Grumm
NEAR TERM...Grumm
SHORT TERM...Grumm
LONG TERM...Ceru/Gartner
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Lincoln IL
859 PM CDT THU OCT 6 2016
.UPDATE...
Issued at 854 PM CDT Thu Oct 6 2016
An area of low pressure, currently centered over Iowa, is forecast
to race northeast to Lake Superior by daybreak Friday. The
trailing cold front should be moving into western portions of the
forecast area by daybreak as well. Showers/storms have been
increasing in coverage along the surface front, associated with a
vigorous upper-level trof and strengthening (currently 40kt) low-
level jet.
Most short-range/high resolution guidance suggests a significant
weakening and/or diminishing coverage of the upstream convection
overnight before the cold front gets here. This seems reasonable
and have only needed to make minor tweaks to tonight`s forecast
for the latest hourly trends.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 245 PM CDT Thu Oct 6 2016
Precipitation shield tracking northeast out of Missouri has been
shrinking over the last couple hours, with associated showers mainly
west of the Illinois River. However, an area of convection has
recently started to fire along the I-55 corridor. Main feature will
be later in the night though, as the cold front works its way
eastward. Latest HRRR shows main area of showers and thunderstorms
from southwest Wisconsin into southwest Missouri at midnight, but on
a weakening trend, and other high-resolution models show a similar
trend as the precipitation pushes into central Illinois. Have
largely limited the overnight PoP`s to areas along and west of the
Illinois River, and east of there to the Indiana border and north of
I-70 Friday morning into early afternoon.
The front itself should be near the Indiana border by midday,
resulting in a large temperature gradient across the forecast area.
Highs in the 70s still expected from about I-57 eastward with a few
80 degree readings near the Wabash Valley, while low-mid 60s prevail
from I-55 west.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 245 PM CDT Thu Oct 6 2016
500 mb trof axis forecast to shift to our east Friday night taking
any lingering threat for showers to our east early in the evening.
The upper flow will then transition more to a zonal flow into a good
portion of next week bringing mainly dry conditions with temperatures
slightly above normal for the second week of October. It appears the
coolest temperatures this period will be on Saturday when early morning
lows drop into the low and mid 40s with afternoon highs mainly in the
upper 60s. After that, we look for temperatures to rise back into the 70s
starting on Sunday and the continuing into the new work week.
As we head into the second half of the week, medium range models suggest
a trof will shift east into the Midwest bringing a front across the region.
However, moisture appears to be rather limited ahead of this feature, as a
result, will only be carrying low chance POPs for isolated showers ahead
of the trof Wednesday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 649 PM CDT Thu Oct 6 2016
The main aviation forecast problem revolves around a cold front
that will clear the area during the second half of the 00Z TAF
valid time. At this point it appears the most of central Illinois
should have a dry frontal passage, but a period of MVFR CIGS is
possible in the vicinity of the front, especially at KPIA, KBMI,
and KSPI. For now, have left precipitation mention out, and only
carried a few hour TEMPO for MVFR conditions at the western
terminals.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Bak
SHORT TERM...Geelhart
LONG TERM...Smith
AVIATION...Bak
Area Forecast Discussion
National Weather Service Northern Indiana
727 PM EDT Thu Oct 6 2016
.SYNOPSIS...
Issued at 223 PM EDT Thu Oct 6 2016
Dry conditions are expected overnight with lows around 60.
A passing cold front will then bring another chance for scattered
showers and isolated thunderstorms Friday afternoon and evening.
Much cooler weather is expected behind this front with highs on
Saturday near 60 degrees and lows near 40. Temperatures moderate
by next week though with dry conditions persisting.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 223 PM EDT Thu Oct 6 2016
Composite outflow from decaying convective complex that shifted
out of ne IL this morning firing isolated storms from here ne.
Better near term focus immediately upstream over ern IL within
area of enhanced sfc convergence and increasing cape. Prior hrrr
solutions along with 12Z SPC NNM initiate storms in this area this
aftn which then tracks ne into srn MI. Prior update followed this
idea and held.
Otherwise dry tonight into Fri am as dynamical focus shifts west
along approaching cold frontal boundary extending southward of
disturbance lifting up across the wrn lakes. Essentially slowed w-e
progression of pops Fri versus previous fcst. Best implied low
chance timed with peak diurnal destablization Fri aftn cntrl/ern IN
zones.
&&
.LONG TERM...(Friday Night through Thursday)
Issued at 223 PM EDT Thu Oct 6 2016
Brief but modest post frontal cold advection wraps in Sat
followed by rapid moderation thereafter as high zonal flow
develops across the Conus. Mos guidance temps have oscillated
somewhat last several cycles with latest blends looking a bit
underdone dys 5-7.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 724 PM EDT Thu Oct 6 2016
VFR this evening with just some mid level clouds. Isolated showers
remain away from terminals and no impact expected. Still a low
chance for some MVFR BR again overnight but winds in the 3-5kt
range may keep lower levels mixed just enough to limit radiational
cooling. No plans to add any BR at this time but winds will be
watched late evening for any additional decoupling.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...T/AGD
SHORT TERM...T
LONG TERM...T
AVIATION...Lashley
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Area Forecast Discussion
National Weather Service Norman OK
922 PM CDT THU OCT 6 2016
.DISCUSSION...
The strong cold front extended from near Stillwater to
Clinton/Weatherford to Elk City at 9 pm. It continues to advance
quickly to the southeast, generating strong thunderstorms as it
goes. The strongest storms, however, are ahead of the front,
between Duncan, Oklahoma and the Wichita Falls area of Texas. In
addition, a small mesolow has developed south of El Reno, helping
to produce strong winds along, and just south of, the Canadian
River between Hinton and Mustang. The front will eliminate this
mesolow within an hour.
The front is expected to continue its rapid advance, taking the
convection with it. Rain/storms will gradually end from northwest
to southeast (some rain will linger well behind the front)
overnight into Friday morning. Rain will finally end in our Texas
counties sometime late tomorrow morning.
We made some minor updates to the forecast earlier this evening,
and will continue to do so as needed.
CmS
&&
.PREV DISCUSSION... /issued 629 PM CDT THU OCT 6 2016/
DISCUSSION...
The 00Z aviation discussion follows....
AVIATION...
At 23Z a strong cold front was just entering the northwest corner
of Oklahoma (east of the Panhandle), approaching KGAG and KWWR.
Strong north winds will follow this front as it moves swiftly
south across Oklahoma and north Texas this evening and after
midnight tonight. In addition, scattered severe TSRA will precede
the front this evening, while a nearly solid line of TSRA is
expected near/behind the front as it advances southeast this
evening. TSRA/SHRA will gradually clear from north to south late
this evening through tomorrow morning. By Friday afternoon, all
our Oklahoma sites should be wide open VFR, and the north wind
will begin to diminish slowly. KSPS will be the last to
clear...probably Friday evening.
CmS
PREV DISCUSSION... /issued 248 PM CDT THU OCT 6 2016/
DISCUSSION...
A few storms have formed this afternoon near the Kansas and Oklahoma
border along and north of an outflow boundary. Farther west, a
few weak radar returns in western Oklahoma are associated
with increasing cloud cover & along an 9-85h moisture gradient.
Several HRRR runs develop storms across southwest/west central
Oklahoma this afternoon with increasing coverage as storms move
eastward through the early evening. Additional storms are expected
to form along a cold front in northwest/north central Oklahoma by
early evening.
35-40 kts of deep layer shear and moderate to high instability should
result in several severe storms, with the best chance during the
late afternoon and early evening. The best tornado
potential appears to be across far north central Oklahoma/southern
Kansas along and near a retreating outflow boundary (back winds &
lower LCL).
Storms will continue to form along a cold front during the evening
and overnight with a risk of hail and damaging winds. Showers
and storms may linger for several hours behind the surface front
as elevated instability will be around 500 J/KG.
Showers and storms will clear southern Oklahoma and north Texas by
mid to late Friday morning.
Showers and thunderstorm chances will increase Sunday into Monday
as a trough lifts across the central Plains.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 51 65 45 73 / 70 0 0 0
Hobart OK 51 65 44 72 / 60 10 0 0
Wichita Falls TX 55 67 48 75 / 90 30 0 0
Gage OK 42 66 40 75 / 10 0 0 0
Ponca City OK 49 66 40 74 / 80 0 0 0
Durant OK 61 70 53 79 / 90 30 0 0
&&
.OUN Watches/Warnings/Advisories...
OK...Flood Watch until midnight CDT tonight for OKZ007-008-012-013-
020.
TX...None.
&&
$$
23/23
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
400 AM EDT FRI OCT 7 2016
.DISCUSSION...
With the last of the overnight showers off to the north, expect dry
conditions through the morning and really not even much cloud cover
either. Full sun will then give a jump to already mild temperatures
that will start the day in the upper 50 to lower 60s which are not
too far from normal highs this time of year. Most locations will be
able to reach highs in the upper half of the 70s before the cold
front arrives and possibly touch the lower 80s closer to the Ohio
border judging by temperature performance yesterday. These readings
are still below record highs which are still running around 90 for
today.
The cold front remains on schedule to enter SE Michigan during mid
afternoon and to exit eastward by midnight. The various runs of
mesoscale and synoptic scale models in the 00Z package continue to
depict a subdued response of surface based convection despite the
frontal passage during peak heating. The HRRR and the NAM do offer a
narrow time window for initiation before transitioning to
postfrontal/elevated development. This is quite a bit different than
what was observed upstream yesterday as surface based convection had
greater coverage, some of which was still going over Wisconsin and
Illinois at issuance time. However, there will be time for warmer
air aloft to surge northward ahead of the front which may not be
strong enough for a cap but at least delay initiation and/or
minimize CAPE density. Model soundings hint at that occurring before
some cooling aloft arrives with the next upper wave and before
entrance region upper jet support catches up to the lower levels of
the frontal zone. A standard elevated pattern of showers should then
follow closely to model depictions with just enough elevated
instability to keep a rumble of thunder mentioned in the forecast.
Surface high pressure will then expand broadly over the Great Lakes
by Saturday with enough cold advection post front to bring
temperatures in check through the weekend. A return to readings at
or slightly below normal for early October will be accompanied by
dry weather into early next week.
&&
.MARINE...
A low pressure system over western Wisconsin will lift northeastward
through Lake Superior this morning. The low will pull a cold front
through the eastern Lakes this evening and early tonight. Increasing
southwest flow ahead of the front will result in a slight uptick in
winds but stability from warm air advection will limit gust
potential. Strongest winds today will occur over northern Lake Huron
closer to the low with Lakes St Clair and Erie gusts remaining below
15 knots. The frontal passage this evening and early tonight will
bring about a quick wind shift to the northwest while decreasing
stability due to colder air allows winds to increase slightly with
some gusts exceeding 20 knots. Wind direction should keep the higher
waves offshore enough so that a small craft advisory should not be
needed. In addition to the elevated winds, the front will produce
some showers and thunderstorms over Lake Huron this evening,
spreading southward across Lakes St Clair and Erie tonight. These
storms are not expected to be severe.
&&
.PREV DISCUSSION...
Issued at 1151 PM EDT Thu OCT 6 2016
AVIATION...
Lingering showers may bring period of MVFR cigs and/or vsbys To KMBS
early in the forecast. Otherwise, expect VFR conditions more or less
through the night into much of Friday. A cold front will then move
through the area 02z-04z or so Friday evening and bring the chance
of showers (possible thunder) with MVFR conditions. Southeast winds
will veer to the southwest by midday Friday and then northwest in
the wake of cold FROPA.
For DTW...VFR conditions are expected through the forecast with an
MVFR ceilings holding off until after 04z Friday as a cold front and
associated scattered showers work into the area.
//DTW Threshold Probabilities...
* Low for ceilings aob 5000 feet late Friday evening.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
DISCUSSION...BT
MARINE.......DRK
AVIATION.....DG
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Marquette MI
519 AM EDT Fri Oct 7 2016
.SHORT TERM...(Today and tonight)
Issued at 518 AM EDT FRI OCT 7 2016
WV imagery and RAP analysis indicated a mid/upper level low over
Manitoba with a trough extending southward through the plains. A
vigorous shortwave trough over srn MN was lifting quickly to the
northeast. At the surface, low pressure was located over wrn Upper
Michigan with a cold front to the sw through wrn WI. A band of
moderate to heavy shra and embedded ts was lifting quickly through
Upper Michigan supported by deep layer qvector conv ahead of the
shrtwv and 45-50 knot 850 inflow ahead of the 850 mb warm front.
Today, expect the pcpn to move out quickly over the w half of the
cwa but linger til afternoon over the east as the low moves away
from the area, per radar trends and short term high res models fcst.
A surge of strong west winds should develop behind the cold front
over the nw cwa btwn 12z-15z supported by a strong isallobaric
component with 5-6 mb/3 hr pres rise. Reduced stability with 850 mb
temps falling from 11C to -2C from 12z to 18z will also aid sfc wind
gust potential as the increasing pres gradient supports strong winds.
Fcst mixing heights suggest gusts in the 35-40 knot will develop over
the Keweenaw where a wind advisory was posted from 14z-21z.
Otherwise, wind gusts over the rest of the area should remain in the
20-30 mph range. Temps will fall from 12z highs into the upper 40s
and lower 50s during the afternoon.
Tonight, wrly flow with 850 mb temps dropping to near -3C and
increasing 850-700 mb moisture will support sct lake effect pcpn
over the nw cwa and locations along Lake Superior e of Munising.
With wet-bulb zero heights dropping below 1500 ft over the inland
west, some light snow/graupel may mix with the -shra but is not
expected to accumulate. The cold airmass will drop temps into the low
to mid 30s inland over the west half and into the upper 30s east.
.LONG TERM...(Saturday through Thursday)
Issued at 440 AM EDT FRI OCT 7 2016
After a trof lifts across the Great Lakes region today thru Sat, a
lower amplitude/more zonally oriented flow will develop early next
week. As a result, the shot of colder air/blo normal temps that
occurs behind the passing trof today thru Sat will be short lived
with moderation beginning on Sun. By mid to late week, 2 negative
height anomaly centers will emerge, one in central Canada and one in
the ne Pacific. A pair of shortwaves will track across southern
Canada as the central Canada trof deepens with the second assisting
in some amplification of the trof southward into the far northern
Plains and Upper Lakes mid week. Waa ahead of the 2 shortwaves will
bring a return of above normal temps for Mon/Tue, the theme for
autumn so far. Then, the slight ampification of the central Canada
trof will allow a cooler air mass to follow for Wed...temps back
down to around normal. Although there have been some inconsistency
in the details of the late week pattern from the GFS and ECMWF in
recent days, the overall consensus of those model runs has been for
the deepening ne Pacific negative height anomaly, which will be at a
lower latitude than the central Canada anomaly, to force some
retreat of the central Canada trof. As a result, it appears broad
wsw flow will develop across much of the CONUS downstream of the
deep ne Pacific trof, allowing above normal temps to return here
again late next week. The deep ne Pacific trof looks like it will be
a persistent feature thru the mid month period per CPC/NAEFS
outlooks, suggesting above normal temps should overall prevail thru
mid to even late Oct, and any periods of blo normal temps will be
short lived. As for pcpn, chilly air mass will lead to some lake
effect pcpn thru Sat night/Sun morning, then aforementioned pair of
shortwaves may generate some pcpn in the late Mon to Wed time frame.
Later in the week, energy swinging off the ne Pacific will probably
bring some shra at some point Fri/Sat.
Beginning Sat into Sat night...850mb temps of -2 to -3C over the
relatively warm waters of Lake Superior and a passing shortwave will
support at least sct lake effect -shra over nw Upper MI and the
eastern fcst area as w winds veer nw and even n with time. Shortwave
in question is actually a potent, very well-defined feature on water
vapor imagery over Vancouver Island. All models dramatically weaken
this shortwave as it tracks ese to the Great Lakes, so it`s not
likely to have much affect on ongoing lake effect pcpn as it passes
Sat evening. Not out of the question that there could be some snow
flakes mixed in Sat morning over the highest terrain s of the
Keweenaw and over higher terrain of western Marquette and Baraga
counties as wet bulb zero heights fall aob 1000ft. Away from lake
effect shra/clouds, some frost, maybe a freeze, will be possible Sat
night if there is not too much cloud cover. As a note, the
frost/freeze headline program for west and central Upper MI ends
today.
Any lingering lake effect shra will end Sun morning as high pres
passes. Attention then turns to developing waa/isentropic ascent
pattern downstream of a shortwave moving across sw into s central
Canada. As was the case yesterday, medium range guidance still shows
strongest isentropic ascent passing n of Upper MI late Sun into
early Mon. So, no pcpn is expected with this first shortwave as it
tracks into northern Ontario on Mon. Mon looks to be a warm day as
850mb temps rise to 12-14C. Expect highs at least into the mid/upper
60s. 70s certainly possible if the entire day ends up mostly sunny.
It should be breezy as well as mostly sunny skies and resulting
heating build mixed layer to tap into 30+kt winds. Wind will also be
enhanced isallobarically by a pres fall max of 4-5mb/3hr moving
across northern Ontario. For now, fcst will show gusts of 20-30mph
Mon.
As lead shortwave lifts ne Mon night, associated cold front will
move se, passing across Upper MI Tue aftn/night. At the same time,
second shortwave catching up to the front will bring a modest
increase in deep layer forcing. This should lead to some -shra
development Mon night thru Wed morning. At this time, looks like
shra coverage will not be widespread. Max temps in the 60s Tue ahead
of the front will fall back to the 50s behind the front for Wed.
Some lake effect -shra could follow into Wed night/Thu morning
depending on how cold the incoming air mass is. 00Z ECMWF/GFS are
cold enough to generate some lake effect pcpn as 850mb temps fall to
at least -4C.
00z medium range model runs are slower to bring the expected late
week warming trend to the area, so highs on Thu should be in the
50s. Temps likely to swing back above normal Fri/Sat, and there may
be some -shra depending on possible energy swinging off the ne
Pacific and across the CONUS.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 146 AM EDT FRI OCT 7 2016
IFR/LIFR Conditions will continue overnight as rain spreads across
Upper Michigan and southerly flow brings abundant low level moisture
and upslope conditions across the area. A few tsra are possible as
the heavier rain moves through overnight. Though flight conditions
improve on Friday, probably very quickly, the main issue will be
very strong west winds. West winds may gust to 30 kts at IWD and SAW
and 40 kts at CMX.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 422 PM EDT THU OCT 6 2016
After 30-35kts winds earlier, expect brief lull this evening.
Deepening low pressure system moves in late tonight. ESE winds to 30
kts with possible gale gusts will shift N late tonight then to the W
on Fri morning as the low moves north of Lk Superior. Expect W-NW
gales 35-40 kts across especially central and eastern Lk Superior on
Fri. Gale warnings are in effect for the entire lake, ending latest
on eastern Lk Superior. NW winds to 30 kts will linger Fri night
with winds to 25 kts on Sat. Winds will diminish to under 15kt late
Sat into early Mon as high pres moves across. SW winds will increase
to 30 kts later Mon and Mon night ahead of another low pressure
system then shift to the north to 25 kts behind the system on Tue.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Wind Advisory from 10 AM this morning to 5 PM EDT this afternoon
for MIZ001-003.
Lake Superior...
Gale Warning until midnight EDT tonight for LSZ243-244-264>267.
Gale Warning until 2 PM EDT /1 PM CDT/ this afternoon for LSZ162.
Gale Warning from 11 AM this morning to midnight EDT tonight for
LSZ249>251.
Gale Warning until 6 PM EDT this evening for LSZ245>248.
Gale Warning until midnight EDT /11 PM CDT/ tonight for
LSZ240>242-263.
Lake Michigan...
Gale Warning until 2 PM EDT this afternoon for LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...Rolfson
AVIATION...07
MARINE...JLA
Area Forecast Discussion
National Weather Service San Diego CA
300 AM PDT FRI OCT 7 2016
.SYNOPSIS...
Patchy low clouds and dense fog will occur along the San Diego County
Coast early this morning. Further inland, locally gusty northeast
winds will occur through and below passes and canyons this morning.
Otherwise, mostly clear skies with very warm weather and low
humidity inland will prevail through Sunday. A trough of low
pressure will develop next week and bring a cooling trend Monday
through Thursday, a return of coastal night and morning low
clouds and increasing westerly winds in the mountains and deserts.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Patchy stratus and fog formed in coastal San Diego County due to a
very shallow marine layer and some coastal dew points near 60, but
otherwise just a few high clouds were drifting over. Local WRF and
HRRR have the stratus/fog dissipating and/or retreating off the
coast early, though lack of offshore flow making it near the coast
before mid-morning could result in fog lingering along the immediate
coast until then. Where the offshore flow reaches today, which will
be most areas more than 10 miles inland, except closer to the coast
in parts of Orange County and northern San Diego County, it should
be quite warm, with most low-elevation temps in the upper 80s to mid
90s. High-res models show the winds not too strong, but some gusts
in the 40s should occur below Cajon Pass and possibly Banning Pass,
in the Santa Ana Mountains/Foothills and a few choice locations in
the San Diego County Mountains. The wind advisory will continue
until 2 PM today, though most areas will be a little below criteria.
Winds should decrease this afternoon, though lingering a few hours
longer until mid-afternoon in San Diego County, versus areas further
north.
The very warm weather will continue through Sunday, though with the
low humidity and limited clouds and wind, the nights will be cool,
with mostly 50s in the valleys. Right now, model guidance does not
have any stratus/fog returning to the coast tonight, with the most
likely chance of return being Sunday night. There will be troughing
forming over the East Pac early next week, which should move through
California Tuesday with possibly a stronger deeper trough around
Wednesday or Thursday. Moisture, which could be quite plentiful,
will remain well north of our area (northern California and points
north), so we should continue to be dry all of next week. With the
onshore flow and lower heights/thicknesses, temperatures will be
lower, probably a little below normal by about Wednesday. The marine
layer will become more dominant, with stratus possibly extending in
the valleys at night, and starting around Tue/Wed, gusty westerly
winds will occur from the mountain crests east into the deserts.
&&
.AVIATION...
070900Z...Low stratus clouds have formed along the coast in southern
Orange County and mainly northern San Diego County. There is a
slight risk that clouds will form inland enough to impact KSAN and
especially KCRQ. Bases are around 2-500 feet above mean sea level.
There is also some reduction in visibility in a few coastal areas as
well with prevailing visibility remaining 2-5 SM or greater, but
some isolated areas may drop under 1 Sm. The fog and low stratus
should burn off shortly after sunrise, to 071800Z at the latest.
Strong northeast winds possible in the mountains and foothills
between 071000-072000Z Friday, with 20 to 30 knots and gusts to 35
knots at times. LLWS at times at KONT. Otherwise VFR and mostly
clear conditions into Saturday.
&&
.MARINE...
Friday morning until around 10 or 11 am there is a risk of some low
stratus clouds and patchy fog, otherwise no hazardous marine weather
is expected through Monday.
&&
.FIRE WEATHER...
The Red Flag Warning continues through 2 PM today for the San
Bernardino and Riverside County Mountains, Inland Empire, Santa Ana
Mountains, and Inland Orange County.
Locally gusty northeast to east winds and widespread very low
humidity will continue in the mountains, foothills, and inland
valleys today. Minimum humidities will be mostly 5-10 percent with
local winds of 15-25 mph and gusts 35-45 mph. Winds will decrease
substantially between noon and 3 PM, with east-west passes/canyons
having the latest decrease of wind. Humidities will recover somewhat
tonight with slight moistening Saturday with min humidities of 10-15
precent and mostly light winds.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX Watches/Warnings/Advisories...
CA...Red Flag Warning until 2 PM PDT today for Orange County Inland
Areas-Riverside County Mountains-Including The San Jacinto
Ranger District Of The San Bernardino National Forest-San
Bernardino County Mountains-Including The Mountain Top And
Front Country Ranger Districts Of The San Bernardino
National Forest-San Bernardino and Riverside County Valleys
-The Inland Empire-San Gorgonio Pass Near Banning-Santa
Ana Mountains-Including The Trabuco Ranger District of the
Cleveland National Forest.
Wind Advisory until 2 PM PDT today for Orange County Inland
Areas-San Bernardino and Riverside County Valleys-The
Inland Empire-Santa Ana Mountains and Foothills.
PZ...None.
&&
$$
PUBLIC/FIRE WEATHER...Maxwell
AVIATION/MARINE...Pierce
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
617 AM EDT FRI OCT 7 2016
.AVIATION...
VFR conditions through much of the day with only increasing cloud
debris shed from upstream convection along a cold front. The front
will bring showers and possibly a few thunderstorms to the MBS and
FNT after about 22Z, spreading southeast toward the Detroit
terminals closer to 03-06Z. Models are still advertising a lower
coverage event thus keeping with the prob30 group for now. In
addition to shower and thunder chances, MVFR ceilings may occur
along the front for a few hours. Otherwise, dry air and clear skies
will quickly work back into the region with northwesterly flow
behind the front between 06-12Z Saturday morning.
For DTW...VFR conditions are expected through the forecast with an
MVFR ceilings holding off until after 04z Friday as a cold front and
associated scattered showers work into the area.
//DTW Threshold Probabilities...
* low for ceilings aob 5000 feet early tonight for a few hours.
&&
.PREV DISCUSSION...
Issued at 400 AM EDT Fri OCT 7 2016
DISCUSSION...
With the last of the overnight showers off to the north, expect dry
conditions through the morning and really not even much cloud cover
either. Full sun will then give a jump to already mild temperatures
that will start the day in the upper 50 to lower 60s which are not
too far from normal highs this time of year. Most locations will be
able to reach highs in the upper half of the 70s before the cold
front arrives and possibly touch the lower 80s closer to the Ohio
border judging by temperature performance yesterday. These readings
are still below record highs which are still running around 90 for
today.
The cold front remains on schedule to enter SE Michigan during mid
afternoon and to exit eastward by midnight. The various runs of
mesoscale and synoptic scale models in the 00Z package continue to
depict a subdued response of surface based convection despite the
frontal passage during peak heating. The HRRR and the NAM do offer a
narrow time window for initiation before transitioning to
postfrontal/elevated development. This is quite a bit different than
what was observed upstream yesterday as surface based convection had
greater coverage, some of which was still going over Wisconsin and
Illinois at issuance time. However, there will be time for warmer
air aloft to surge northward ahead of the front which may not be
strong enough for a cap but at least delay initiation and/or
minimize CAPE density. Model soundings hint at that occurring before
some cooling aloft arrives with the next upper wave and before
entrance region upper jet support catches up to the lower levels of
the frontal zone. A standard elevated pattern of showers should then
follow closely to model depictions with just enough elevated
instability to keep a rumble of thunder mentioned in the forecast.
Surface high pressure will then expand broadly over the Great Lakes
by Saturday with enough cold advection post front to bring
temperatures in check through the weekend. A return to readings at
or slightly below normal for early October will be accompanied by
dry weather into early next week.
MARINE...
A low pressure system over western Wisconsin will lift northeastward
through Lake Superior this morning. The low will pull a cold front
through the eastern Lakes this evening and early tonight. Increasing
southwest flow ahead of the front will result in a slight uptick in
winds but stability from warm air advection will limit gust
potential. Strongest winds today will occur over northern Lake Huron
closer to the low with Lakes St Clair and Erie gusts remaining below
15 knots. The frontal passage this evening and early tonight will
bring about a quick wind shift to the northwest while decreasing
stability due to colder air allows winds to increase slightly with
some gusts exceeding 20 knots. Wind direction should keep the higher
waves offshore enough so that a small craft advisory should not be
needed. In addition to the elevated winds, the front will produce
some showers and thunderstorms over Lake Huron this evening,
spreading southward across Lakes St Clair and Erie tonight. These
storms are not expected to be severe.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....DRK
DISCUSSION...BT
MARINE.......DRK
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1053 AM CDT Fri Oct 7 2016
.UPDATE...
1028 AM CDT
For Morning Update...
Little change to going forecast this morning, which appears to
remain in very good shape. Only minor tweak is to remove slight
chance pops for thunder this afternoon.
Surface cold front was pushing east across the Chicago metro area
at mid-morning, with a wind shift to the west-northwest, band of
post-frontal cloud cover, and temps falling into the 50`s noted
in the wake of the front. Currently, no precipitation was
occurring along/near the front, though various guidance members
including the 09z SREF, several recent HRRR runs, and the 00Z
ECMWF all try to squeeze out a little post-frontal light rain
through this afternoon. This appears to be associated with
forcing derived from the combination of the tail of the mid-level
short wave trough seen in water vapor imagery approaching the
Mississippi Valley, upper divergence in the right entrance region
to the 100+ kt southwesterly upper level jet streak translating
across the area this afternoon, and moderately strong
frontogenetic forcing within the elevated baroclinic zone around
850 mb behind the surface front. This looks to be fairly limited
in scope and intensity, though can`t argue with going slight
chance pops. Do think that the thunder threat will be non-existent
as what little weak MUCAPE depicted in SPC RAP-based mesoanalysis
will be east of the cwa shortly, and forecast soundings do not
indicate any substantial positive area.
Ratzer
&&
.SHORT TERM...
303 AM CDT
Through tonight...
A strong cold front will sweep across the region today ushering in
a cooler and much drier airmass. Early this morning, low
pressure is centered over northern Wisconsin with a cold front
stretching south into far eastern Iowa. Temperatures in the mid to
upper 60s are noted immediately ahead of the front across portions
of far eastern Iowa, then drop sharply into the low 40s behind the
front. The cold front is expected to push across the Rockford
area by mid morning and much of the Chicago metro area by late
morning or early afternoon. Given the unfavorable diurnal timing,
expect the front to pass through most of the CWA dry with only a
slight chance of a shower. This afternoon, very modest instability
is expected to develop mainly east of a Gary to Paxton line and
cannot rule out a few widely scattered showers or thunderstorms
developing.
High pressure builds in quickly behind the front resulting a
strong pressure gradient and isallobaric response which will drive
strong winds from late morning through the afternoon when gusts of
20 to 25 mph are expected with a few peak gusts near 30 mph
possible at times. Strong flow behind the front will help to
transport cooler temperatures into the region as well. For
portions of north central Illinois, high temperatures will be in
the low 60s early this morning with steady or falling temperatures
expected behind the front. Meanwhile, southeastern portions of the
CWA will warm into the low to mid 70s this afternoon before the
front passes through. A couple hours of post-frontal stratus
should give way to clearing skies as a notably drier air mass
advects into the region and winds will drop off late this evening
and overnight as the high settles across the mid-Missouri Valley
with ridging extending across northern Illinois and Indiana. With
favorable radiational cooling setup, expect overnight lows into
the 30s across portions of northern Illinois west of the Fox River
Valley with low to mid 40s farther east. Downtown Chicago and
immediate area should hold onto mid to upper 40s.
Deubelbeiss
&&
.LONG TERM...
303 AM CDT
Saturday through Thursday...
Strong area of high pressure will build into the upper Midwest and
Great Lakes over the weekend and gradually inch east becoming
centered over the eastern Great Lakes Monday. Expect a gradual
warming trend through this time frame with highs initially in the
low to mid 60s Saturday and eventually rising back into the low
70s Monday and Tuesday. Dry weather will prevail under the
influence of the high.
A strong upper wave is progged to dig across the Canadian Prairies
late Monday through Tuesday carving out an upper level trough
that will extend into portions of the Midwest and sending another
cool air mass towards the region. The GFS brings the 0C 850mb
isotherm into northern Illinois Wednesday while the ECMWF shunted
it nearly 150 miles farther north. If the GFS verifies, current
forecast temperatures will be considerably too warm, and would
expect to see a decent setup for frost Thursday morning with
surface high building into the region. Given model differences do
not have enough confidence to change from the consensus blend, but
will have to keep an eye on this timeframe for potential changes
to the forecast as it gets closer in time. Both the GFS and ECMWF
advertise a warmup for late in the week into next weekend, along
with the potential for more active weather.
Deubelbeiss
&&
.AVIATION...
For the 12Z TAFs...
The aviation forecast concerns for today are mainly through early
afternoon, with a cold frontal passage bringing gusty west-
northwest winds and then likely a few hour window of temporary to
prevailing MVFR cigs.
The cold front stretches from south central Wisconsin through
western Illinois as of 1130Z. This front will continue moving east
with mainly dry conditions along it, though cannot completely rule
out not receiving any rain. Immediately behind the front there has
been a fairly constant area of MVFR cigs, and even some IFR. Given
IFR is being observed along the IA/IL border, would expect it to
at least be close to Rockford by 13Z. MVFR cigs are now more
likely to make it into Chicago with medium confidence, though
timing/duration is low-medium confidence. But these should lift
and scatter at some point around or shortly after noon. West to
northwest winds will gust to 20-23 kt a good part of today in the
post frontal air mass.
MTF
&&
.MARINE...
152 AM CDT
Southerly winds over the lake early this morning will continue to
increase through mid-morning before making an abrupt turn to the
west-northwest behind a cold front. The low pressure driving this
is taking a favorable path for gales across the north, though its
magnitude/strength is not as deep as a typical gale event. So
gales are probable to be more occasional on the north end this
morning.
Behind the frontal passage, the winds will be gusty out of the
west with cooler air moving in helping to increase mixing. Small
craft advisory gusts of 22-25 kt are expected late this morning
and afternoon along the Illinois and Indiana nearshore with
medium-high confidence. Waves will likely remain above 4 ft along
a good part of the northwest Indiana shore through Saturday
morning.
Beyond, winds will turn northeast on Sunday behind a weak backdoor
cold front before turning back south again early next week with
the approach of the next low pressure system from the northern
Plains.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...Small Craft Advisory...INDIANA NEARSHORE WATERS UNTIL 10 AM Saturday.
Small Craft Advisory...ILLINOIS NEARSHORE WATERS UNTIL 7 PM Friday.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
744 AM EDT Fri Oct 7 2016
.SHORT TERM...(Today and tonight)
Issued at 518 AM EDT FRI OCT 7 2016
WV imagery and RAP analysis indicated a mid/upper level low over
Manitoba with a trough extending southward through the plains. A
vigorous shortwave trough over srn MN was lifting quickly to the
northeast. At the surface, low pressure was located over wrn Upper
Michigan with a cold front to the sw through wrn WI. A band of
moderate to heavy shra and embedded ts was lifting quickly through
Upper Michigan supported by deep layer qvector conv ahead of the
shrtwv and 45-50 knot 850 inflow ahead of the 850 mb warm front.
Today, expect the pcpn to move out quickly over the w half of the
cwa but linger til afternoon over the east as the low moves away
from the area, per radar trends and short term high res models fcst.
A surge of strong west winds should develop behind the cold front
over the nw cwa btwn 12z-15z supported by a strong isallobaric
component with 5-6 mb/3 hr pres rise. Reduced stability with 850 mb
temps falling from 11C to -2C from 12z to 18z will also aid sfc wind
gust potential as the increasing pres gradient supports strong winds.
Fcst mixing heights suggest gusts in the 35-40 knot will develop over
the Keweenaw where a wind advisory was posted from 14z-21z.
Otherwise, wind gusts over the rest of the area should remain in the
20-30 mph range. Temps will fall from 12z highs into the upper 40s
and lower 50s during the afternoon.
Tonight, wrly flow with 850 mb temps dropping to near -3C and
increasing 850-700 mb moisture will support sct lake effect pcpn
over the nw cwa and locations along Lake Superior e of Munising.
With wet-bulb zero heights dropping below 1500 ft over the inland
west, some light snow/graupel may mix with the -shra but is not
expected to accumulate. The cold airmass will drop temps into the low
to mid 30s inland over the west half and into the upper 30s east.
.LONG TERM...(Saturday through Thursday)
Issued at 440 AM EDT FRI OCT 7 2016
After a trof lifts across the Great Lakes region today thru Sat, a
lower amplitude/more zonally oriented flow will develop early next
week. As a result, the shot of colder air/blo normal temps that
occurs behind the passing trof today thru Sat will be short lived
with moderation beginning on Sun. By mid to late week, 2 negative
height anomaly centers will emerge, one in central Canada and one in
the ne Pacific. A pair of shortwaves will track across southern
Canada as the central Canada trof deepens with the second assisting
in some amplification of the trof southward into the far northern
Plains and Upper Lakes mid week. Waa ahead of the 2 shortwaves will
bring a return of above normal temps for Mon/Tue, the theme for
autumn so far. Then, the slight ampification of the central Canada
trof will allow a cooler air mass to follow for Wed...temps back
down to around normal. Although there have been some inconsistency
in the details of the late week pattern from the GFS and ECMWF in
recent days, the overall consensus of those model runs has been for
the deepening ne Pacific negative height anomaly, which will be at a
lower latitude than the central Canada anomaly, to force some
retreat of the central Canada trof. As a result, it appears broad
wsw flow will develop across much of the CONUS downstream of the
deep ne Pacific trof, allowing above normal temps to return here
again late next week. The deep ne Pacific trof looks like it will be
a persistent feature thru the mid month period per CPC/NAEFS
outlooks, suggesting above normal temps should overall prevail thru
mid to even late Oct, and any periods of blo normal temps will be
short lived. As for pcpn, chilly air mass will lead to some lake
effect pcpn thru Sat night/Sun morning, then aforementioned pair of
shortwaves may generate some pcpn in the late Mon to Wed time frame.
Later in the week, energy swinging off the ne Pacific will probably
bring some shra at some point Fri/Sat.
Beginning Sat into Sat night...850mb temps of -2 to -3C over the
relatively warm waters of Lake Superior and a passing shortwave will
support at least sct lake effect -shra over nw Upper MI and the
eastern fcst area as w winds veer nw and even n with time. Shortwave
in question is actually a potent, very well-defined feature on water
vapor imagery over Vancouver Island. All models dramatically weaken
this shortwave as it tracks ese to the Great Lakes, so it`s not
likely to have much affect on ongoing lake effect pcpn as it passes
Sat evening. Not out of the question that there could be some snow
flakes mixed in Sat morning over the highest terrain s of the
Keweenaw and over higher terrain of western Marquette and Baraga
counties as wet bulb zero heights fall aob 1000ft. Away from lake
effect shra/clouds, some frost, maybe a freeze, will be possible Sat
night if there is not too much cloud cover. As a note, the
frost/freeze headline program for west and central Upper MI ends
today.
Any lingering lake effect shra will end Sun morning as high pres
passes. Attention then turns to developing waa/isentropic ascent
pattern downstream of a shortwave moving across sw into s central
Canada. As was the case yesterday, medium range guidance still shows
strongest isentropic ascent passing n of Upper MI late Sun into
early Mon. So, no pcpn is expected with this first shortwave as it
tracks into northern Ontario on Mon. Mon looks to be a warm day as
850mb temps rise to 12-14C. Expect highs at least into the mid/upper
60s. 70s certainly possible if the entire day ends up mostly sunny.
It should be breezy as well as mostly sunny skies and resulting
heating build mixed layer to tap into 30+kt winds. Wind will also be
enhanced isallobarically by a pres fall max of 4-5mb/3hr moving
across northern Ontario. For now, fcst will show gusts of 20-30mph
Mon.
As lead shortwave lifts ne Mon night, associated cold front will
move se, passing across Upper MI Tue aftn/night. At the same time,
second shortwave catching up to the front will bring a modest
increase in deep layer forcing. This should lead to some -shra
development Mon night thru Wed morning. At this time, looks like
shra coverage will not be widespread. Max temps in the 60s Tue ahead
of the front will fall back to the 50s behind the front for Wed.
Some lake effect -shra could follow into Wed night/Thu morning
depending on how cold the incoming air mass is. 00Z ECMWF/GFS are
cold enough to generate some lake effect pcpn as 850mb temps fall to
at least -4C.
00z medium range model runs are slower to bring the expected late
week warming trend to the area, so highs on Thu should be in the
50s. Temps likely to swing back above normal Fri/Sat, and there may
be some -shra depending on possible energy swinging off the ne
Pacific and across the CONUS.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 744 AM EDT FRI OCT 7 2016
Sct shra are expected early in the period as a cold front moves
through with winds veering quickly to the west. Drier air behind the
front will result in VFR vsby. However, enough low level moisture
will linger for mainly MVFR cigs through tonight. Gusty west winds
will develop, especially at KCMX where gusts near 40 knots are
expected today.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 422 PM EDT THU OCT 6 2016
After 30-35kts winds earlier, expect brief lull this evening.
Deepening low pressure system moves in late tonight. ESE winds to 30
kts with possible gale gusts will shift N late tonight then to the W
on Fri morning as the low moves north of Lk Superior. Expect W-NW
gales 35-40 kts across especially central and eastern Lk Superior on
Fri. Gale warnings are in effect for the entire lake, ending latest
on eastern Lk Superior. NW winds to 30 kts will linger Fri night
with winds to 25 kts on Sat. Winds will diminish to under 15kt late
Sat into early Mon as high pres moves across. SW winds will increase
to 30 kts later Mon and Mon night ahead of another low pressure
system then shift to the north to 25 kts behind the system on Tue.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Wind Advisory until 5 PM EDT this afternoon for MIZ001-003.
Lake Superior...
Gale Warning until midnight EDT tonight for LSZ243-244-264>267.
Gale Warning until 2 PM EDT /1 PM CDT/ this afternoon for LSZ162.
Gale Warning from 11 AM this morning to midnight EDT tonight for
LSZ249>251.
Gale Warning until 6 PM EDT this evening for LSZ245>248.
Gale Warning until midnight EDT /11 PM CDT/ tonight for
LSZ240>242-263.
Lake Michigan...
Gale Warning until 2 PM EDT this afternoon for LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...Rolfson
AVIATION...JLB
MARINE...JLA
Area Forecast Discussion
National Weather Service State College PA
640 PM EDT Fri Oct 7 2016
.SYNOPSIS...
Rain will begin over the western highlands this evening as a a
cold front moves in from the west tonight. The3 front will pass
through the region during the day Saturday. Cooler and drier
weather is expected into early next week before a new but mainly
dry cold front approaches Thursday. Hurricane Matthew will remain
off the southeastern US coast and not directly impact our weather.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Tropical plume of moisture lifting into southwest PA ahead of 5h
shear axis lifting northward is bringing light showers to the
Laurel Highlands and West Central Mountains early this evening.
Isolated to scattered activity also detected over portions of the
South Central mountains. This moisture will slowly increase
tonight as southerly flow aloft between approaching Glaks trof and
offshore ridge directs it northward. Forcing remains rather
weak...and so showers will be most favored over the higher
terrain...but expect a gradual eastward progression to shower
chances as 1 to 1.5" PW increase late tonight into Saturday
morning.
With moisture increasing steadily through the night...expect
increasing low clouds and fog after midnight in the NW two-
thirds of the area. However...rain will likely take all night to
get past UNV and may not get to IPT before sunrise. The cold front
should be almost to Warren Co by sunrise. The QPF from the SREF
plumes is very widely dispersed, but the median & mean look close
and also close to the oprnl models. Up to an inch is possible in
the Alleghenies, esp the Laurels. Muggy and mild overnight in the
east.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
The front will move across the area Saturday as a weakening
feature. The band of rain before the front is likely going to
weaken as the front nears, with little moisture left for the
front to lift as it goes by. After a very dismal start to the day
- the NW will brighten nicely during the morning. It will take
much of the aftn for the rain to push east of the central mtns,
and another few hours to clear out. If the clearing happens before
sunset, the high ambient moisture may lead to very a foggy Sat
night. If clearing happens later, widespread fog is not likely.
But, it will almost certainly happen in ye olde valleys of the
north and west. Maxes in the 60s will be just a shade above
normal.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Any lingering showers will exit eastern Pennsylvania Saturday
night. Cold, dry air will advect into the area behind the front.
High pressure will build in behind the front and bring a period
of tranquil but cool weather that will last into the midweek. The
cold air will continue to filter in as the northwesterly flow
continues into Monday morning. This cold air advection could allow
for the first real chance for widespread frost of the season
Sunday night into Monday morning. Models continue to show 850
temps nearing zero with anomalously dry air and light wind
setting in. The main area of concern in through the Northern half
of Central Pennsylvania.
The only possible complication in the medium range could be for
the potential of low clouds returning in a developing maritime
flow by later Tuesday into Wednesday.
The next front is made to approach later Wednesday into Wednesday
night, with another chilly chunk of air expected to follow for
the last days of the work week. The GEFS and EC have significant
timing and placement differences for any significant confidence.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
A moist southeast flow into the Appalachian Mountains is producing
sct showers and MVFR cigs early this evening at KJST and KAOO.
Near term models suggest not much change the rest of the evening
with MVFR reductions possible at KJST/KAOO and VFR likely
elsewhere.
Deteriorating conditions appear likely late tonight, as a moistening
southeast flow results in lowering cigs and an approaching cold
front produces a band of showers from around KBFD south to KJST.
Model soundings and LAMP guidance support the idea of IFR cigs
developing at KBFD/KUNV/KJST/KAOO around 06Z, give or take a
couple hours. The lower elevation airfields further east are
likely to experience a dry night. However, MVFR cigs appear
possible late tonight associated with moistening southeast flow.
Not giving much credibility to the HRRR producing fog at KMDT/KLNS
after midnight, given amount of high clouds and large dwpt
depressions going into the evening.
Low cigs and showers appear likely across the Central Mtns into
early afternoon associated with slow moving cold front, then some
modest improvement is possible late in the day, as drier air
arrives. Across the eastern airfields from KIPT south through
KMDT/KLNS, it looks like MVFR conditions will predominate for much
of the day, with morning cigs in the 1-3KFT range, followed by
scattered rain showers with arrival of front in the afternoon.
Outlook...
Sun...No sig wx expected.
Mon-Wed...Patchy AM fog possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo/DeVoir
SHORT TERM...Dangelo
LONG TERM...La Corte/Ceru
AVIATION...Dangelo/Fitzgerald
Area Forecast Discussion
National Weather Service Omaha/Valley NE
251 PM CDT FRI OCT 7 2016
.SHORT TERM...(Tonight through Monday)
Issued at 250 PM CDT Fri Oct 7 2016
The main forecast concerns in this period are potential for
patchy frost tonight...mainly in our northern zones - and
precipitation chances from Sunday night into Monday.
Water vapor and IR satellite imagery early this afternoon in
combination with recent RUC model initializations showed fairly
quiet weather in our area behind the system that moved through
yesterday. A 100 knot jet max at 300 mb was noted over the Pacific
Northwest ar 12z, associated with a disturbance there. There was
also a disturbance noted moving into southern California. At the
surface...high pressure was noted over the region.
That high pressure will move east/southeast tonight. By sunrise
Saturday, the axis of the high should extend from western Oklahoma
into southeast Minnesota. Our area will be in southerly return
flow, which is expected to develop latest in our far northern
counties. Will mention some patchy frost mainly there, and also in
parts of western Iowa north of Interstate 80.
Southerly flow should bring in some warmer air for Saturday, and
with lots of sunshine we look for highs in the upper 60s and lower
70s. A weak cold front will try to push into our area from the
north Saturday night but then start to lift back north Sunday.
Highs Sunday should be in the lower 70s at most locations.
Southerly flow will strengthen a bit Sunday night into Monday,
bringing in a little more low level moisture and some instability.
Some energy aloft associated with a weak trough will move in from
the west/southwest, so some isolated showers and thunderstorms
appear possible.
.LONG TERM...(Monday night through Friday)
Issued at 250 PM CDT Fri Oct 7 2016
At the start of this period, there will be a blocking ridge in the
mid troposphere from just off the Pacific Northwest coast up into
the Yukon. That should help funnel some colder air from Canada down
into the Northern and Central Plains for Wednesday and Thursday.
The mid level ridge should break down by late in the week...with
temperatures moderating back closer to normal by Friday.
Opted to go with a dry forecast for Monday night but there may be
some isolated activity ahead of the front. Will keep an eye on
that for later forecasts. Did include some low rain chances later
in the week (Tuesday night into Wednesday) and then again from
Thursday into Friday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1238 PM CDT Fri Oct 7 2016
VFR conditions through the period. The low level jet increases
tonight in northeast Nebraska, so added llws to KOFK. These
stronger winds aloft will begin mix down Saturday morning.
&&
.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&
$$
SHORT TERM...Miller
LONG TERM...Miller
AVIATION...Zapotocny