Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/13/17
Area Forecast Discussion
National Weather Service Bismarck ND
1003 PM CST Sun Nov 12 2017
.UPDATE...
Issued at 951 PM CST Sun Nov 12 2017
Based on largely NDDOT webcam trends through 0330 UTC, cancelled
the Dense Fog Advisory for Wells county, but, extended it into
Renville and Bottineau counties. Still plenty of uncertainty in
how the fog will evolve across the north central, whether it will
continue a slow regression north with drier air in southeasterly
winds, or if it will hold more solidly as suggested by the 03 UTC
GFSLAMP.
UPDATE Issued at 757 PM CST Sun Nov 12 2017
Expanded the Dense Fog Advisory to include Burke and Divide
counties per observed trends through 0130 UTC and the consensus of
the 01 UTC RAP/NBM/GFSLAMP and the 00 UTC HRRR visibility
forecasts which favor dense fog focusing into far northwest North
Dakota through the night. The fog has been eroding across
portions of eastern McLean into Sheridan and Wells counties over
the past 1 to 2 hours. Thus, the Dense Fog Advisory may be
cancelled later this evening if trends continue for these counties.
In fact, the CAMs suggest that drier air with southeasterly winds
may erode the fog through Minot by 05-07 UTC.
UPDATE Issued at 552 PM CST Sun Nov 12 2017
Little change with this update. Some uncertainty exists how long
dense fog will last tonight across Sheridan, Wells and possibly
McLean counties with southeasterly winds advecting drier air into
the area. The 23 UTC RAP/NBM/GFSLAMP and 22 UTC HRRR within their
visibility forecasts suggest the fog for these areas decreasing
over the next 1-3 hours. Otherwise, the dense fog is favored by
the aforementioned guidance to remain solidly in place across the
northwest, and potentially expanding towards the international
border of the north central. Modifications to the current Dense
Fog Advisory are certainly possible through the night.
&&
.SHORT TERM...(This evening through Monday)
Issued at 428 PM CST Sun Nov 12 2017
The main forecast issue in the short term continues to be fog/no fog
issues, how dense any fog might become, as well as sky cover. Late
this afternoon decided to issue a dense fog advisory for portions of
northwest and north central ND, mainly along and north of Lake
Sakakawea to the Harvey area. Later shifts may need to expand this
advisory.
Currently, the surface high pressure center was off to our east in
Minnesota/Iowa, with the high pressure axis extending northwestward
into the Devils Lake Basin/Turtle Mountains area. Warm advection
southerly winds were established over western and most of central
North Dakota. Throughout the day, the area of low clouds and fog
that developed early this morning persisted until around noon CST
over northwestern and into parts of central ND...mainly from
McKenzie to Divide counties...east/southeast along Lake
Sakakawea...nearly making its way to the Minot area. There was a
large temperature spread across our area this afternoon, with lower
20s in the Turtle Mountain area to the lower 50s in parts of the
southwest.
The short term high res models continue to depict dense fog
(visibilities of 1/4 mile or less) in most of northwest North Dakota
this afternoon, but by mid-afternoon visibilities there had improved
around noon CST with most areas having visibilities above 3 miles.
It was only after 3 pm when visibilities began to drop. Some area
web cams continued to show some locales with lower visibilities in
fog, especially around Lake Sakakawea and a few points north. The
evolution of fog expansion is the main challenge for tonight.
The high res models indicate the area of low clouds and fog
expanding tonight and moving northward. Thus will have a mention of
widespread fog across all of northwest and north central ND.
The broad ridging aloft continues on Monday, along with southerly
winds. Low clouds and fog should erode from south to north on Monday
as was seen Sunday afternoon. Highs Monday should again be in the
low/mid 50s far southwest, but reach into the 30s in the Turtle
Mountains.
.LONG TERM...(Monday night through Sunday)
Issued at 428 PM CST Sun Nov 12 2017
Deterministic models are in reasonable agreement through mid week.
A cold front moves through the area on Tuesday afternoon/evening
bringing only minimal precipitation chances and a brief cooldown on
Wednesday north and east. Expecting breezy northwest winds late
Tuesday afternoon and night mainly across the northeast half of the
state.
Although there are some differences between the GFS/ECMWF with the
next wave that moves through Thursday/Friday, their solutions,
especially regarding the position of the northern upper trough, have
come into better agreement. We are expecting strong south winds
(especially the James Valley to Turtle Mountains and east) and
seasonable to mild conditions Thursday. Then the cold front moving
through Thursday night with northwest winds developing, and becoming
strong on Friday with colder air moving in. Highs Thursday from 30
to 50 northeast to southwest...cooling to highs Friday from lower
20s north to 30s south. Precipitation chances still look best to the
north and east of our area. Model consensus is still giving mainly
slight chances of light rain or snow for us.
The colder air Friday lingers into Saturday, with a moderate
recovery in the southwest on Sunday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 951 PM CST Sun Nov 12 2017
LIFR/VLIFR conditions in freezing fog will continue across much of
northwest and north central North Dakota tonight through Monday
morning. The fog may continue northwest into Monday afternoon.
Otherwise, VFR conditions are forecast across the southwest and
south central for the 00 UTC TAF cycle.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 6 AM CST Monday for NDZ001>004-009>012-
021-022.
&&
$$
UPDATE...PA
SHORT TERM...JV
LONG TERM...JV
AVIATION...PA
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
703 PM CST Sun Nov 12 2017
.DISCUSSION...Made a few relatively minor tweaks to the overnight
forecast to cover development and potential persistence of
precipitation in various locations across Deep South Texas/RGV and
the Lower Texas coastal waters. The forecast is tricky to say the
least as models are in mixed camps. The 18Z GFS came in with
fairly robust vertical motion in the low levels (sub-700 mb) along
the coast and over the Gulf waters for most of the night through
midday Monday before the energy shifts south by late afternoon.
The ECMWF and to some extent recent runs of the HRRR favor evening
to overnight development along the edge of the differential
diabatic heating zone (it was only in the lower 70s across the Rio
Grande Plains while along US 281 it popped into the mid 80s).
GFS shows some of this as well even at its solution is more
dominated by rainfall over the Gulf. The hunch here is that GFS
is picking up on low level (near surface?) speed convergence as
the midwestern ridge builds south and pressure rises a bit more
overnight than the ECMWF, which shoves its deeper moisture inland
sooner.
Given the unseasonably "soupy" low level airmass (surface
dewpoints in the 70-74 range) it won`t take much to get showers
going just about anytime and anywhere...but climatology favors
better overnight rainfall (QPF) toward the coast vs. inland and
have re-oriented the values that way, while giving a nod for near
0.1" averages over the Hidalgo/Brooks/northeast Starr/eastern Jim
Hogg area. Not enought to dent the drought but better than
nothing.
As for Monday...elected to nudge higher chances toward
Brownsville/Port Isabel in line with guidance consensus for the
morning hours, while keeping the waters south of Port Mansfield a
bit wetter than farther north. The moisture will get a southward
shove by late afternoon as northeast surface winds pick up with
nose ofthe ridge building southwest from the core in the Ohio
Valley, with skies tending toward overcast.
52/BSG
&&
.AVIATION...Similar to the discussion above, TAF forecast is a bit
difficult as well. Impacts, however, shouldn`t be - though can`t
rule out brief IFR visibility in any locally heavier showers that
pass by through the period.
Overall, the overnight should be fairly copacetic with mainly VFR
mid level ceilings. Elected to throw in a few TEMPO groups for
MVFR visibility when it does rain - briefly - since the nature of
the rain is rather tropical given the warm/humid low levels. For
Monday morning, more of the same; ceilings may touch MVFR but
should largely remain in the 3K foot dividing line. By afternoon,
the northeast winds pick up a bit...and would not be surprised to
see some 20 knot gusts but for now have kept sustained in the
10-13 knot range. May see ceilings settle in lower; for now, held
just above the MVFR/VFR line but OVC may be the sense of the sky
with a slight "cooling" compared with today.
52/BSG
&&
.PREV DISCUSSION... /issued 244 PM CST Sun Nov 12 2017/
SHORT TERM (Tonight through Monday Night): Mid level ridging
remains in place over northwest Mexico, extending east over deep
south Texas and the west Gulf. A surface cold front has pushed
into central Texas, but it should dissipate as the main supporting
high pressure over the plains slides off to the east. Some of the
continental high pressure will push out over the north Gulf
tonight, however, backing local wind to east or northeast through
the short term. Kept chance pops in the forecast for tonight and
Monday as coastal convergence and continuing low level moisture
support weak shower activity. By Monday night northeast winds will
be in control and the deepest moisture will be pushed to the
south. Skies should open up a little Monday night but will still
be partly cloudy. Warmer than normal temperatures will continue,
though not too extreme, with overnight lows still in the mid to
upper 60s, about ten degrees above normal, while Monday`s highs in
the lower 80s will be about 5 degrees above normal.
LONG TERM (Tuesday through Sunday): Most of the upcoming week
will be dominated by high pressure in the vicinity at the surface
and aloft. The H5 ridge will be building to the southwest,
providing drier northwest flow aloft, capping off the atmosphere.
At the surface, the ridge will stretch from south Texas all the
way to Maine, providing deeper moisture return into south Texas.
Temperatures will reach above average each afternoon, rising into
the mid to upper 80s. The main weather event is the arrival of the
next cold front sometime on Saturday. Models are still differing
on timing by a good 12 to 18 hours, but are agreeing on a
considerable improvement in temperatures for the latter half of
next weekend.
MARINE:
Now through Monday Night: Moderate northeast to east winds will
develop tonight, with slowly building seas across a long Gulf fetch
as continental high pressure filters south over the north Gulf
coast. The wave models have backed off slightly on the wave heights,
with 4 to 6 feet now forecast, instead of 5 to 7, for the offshore
waters Monday night.
Tuesday through Thursday: Tranquil weather expected for the marine
areas for the middle of the week as surface high pressure remains
just to the northeast. This keeps the gradient weaker, keeping
winds 10 to 15 knots and seas relaxing to around 3 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 71 78 69 81 / 50 60 10 0
BROWNSVILLE 69 80 68 83 / 50 60 10 0
HARLINGEN 69 80 67 82 / 40 50 10 0
MCALLEN 69 81 66 84 / 40 30 10 0
RIO GRANDE CITY 69 81 65 84 / 40 30 10 0
SOUTH PADRE ISLAND 72 77 71 79 / 60 60 10 0
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
Area Forecast Discussion
National Weather Service Columbia SC
935 PM EST Sun Nov 12 2017
.SYNOPSIS...
An approaching cold front will cross the area late tonight into
Monday morning. Dry high pressure will return to the region for
Monday night through Thursday. Another cold front will arrive
early Saturday.
&&
.NEAR TERM /THROUGH TONIGHT/..
Cold front moving into middle TN late this evening. Light
showers have developed ahead the front and are now moving into
the western Midlands. Little convergence will be associated with
the front because of the lingering surface ridging extending
into the area from the north. The main rain support will be an
h85 jet. The models display the greatest moistures and lift
around 100 am especially in the north section. The system is
progressive with little time for moisture recovery so we leaned
toward the lower guidance rainfall amounts. Expect light amounts
of mainly 0.1 south to 0.2 of an inch north. Latest HRRR
indicating the light showers moving slowly through the area
overnight and moving east of the area by around 14Z Monday.
Overnight lows will be mainly in the 40s.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
Monday...There may be lingering moisture associated with the
cold front in the east section early. Otherwise, expect drying
behind the cold front. It will be warmer with afternoon
sunshine. The guidance consensus supports highs in the lower 60s
north to upper 60s south. Lows Monday night will be mainly in
the upper 30s to the lower 40s.
Generally tranquil weather with seasonable temperatures
expected through mid week with broad upper troughing over the
eastern part of the country. Surface high pressure will
continue to build over the area Monday night through Wednesday
in the wake of the departing upper trough off the east coast.
500mb flow will be northwesterly across the forecast area with
north- northeasterly low level flow from the surface through
850mb.
Atmospheric moisture will be very limited with precipitable
water values below 0.5 inches throughout this period leading to
dry conditions enhanced by a strong subsidence inversion. A
fast moving shortwave trough will move through the Ohio Valley
Wednesday and to the Mid-Atlantic coast by late Wednesday night
but moisture associated with the system remains to our north or
precipitates on the upslope side of the Appalachians with
downsloping flow downwind of the higher terrain. Therefore will
continue to carry a dry forecast Wednesday night.
Temperatures will be near to slightly below normal with lows in
the upper 30s to lower 40s and highs in the 60s.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
The extended forecast features a transition to near to slightly
above normal temperatures for the end of the week as 500mb
heights flatten across the southern part of the country with
weak upper ridging over the Ohio Valley and Great Lakes region
ahead of a digging western upper trough. This upper trough will
translate eastward Fri/Sat bringing a cold front through the
forecast area sometime late Friday night or Saturday with
increasing chances of rain. The most recent medium range model
runs have trended a bit slower with ensemble support for slower
timing, while the GFS remains the fastest of them.
The fast moving nature of this trough/front will limit rainfall
potential and overall moisture is not that great with only a
narrow band of higher precipitable water (around 1.25-1.50
inches) immediately preceding the front. There is a relatively
strong 850mb jet around 40-50 knots which will result in breezy
conditions Saturday across the region. Operational models and
ensemble timing differences lead to lower confidence in rainfall
chances and amounts but Saturday is the most likely time frame
at this point. Instability looks minimal but will depend on the
timing of the front, with better instability possible if the
front moves through later Saturday.
High pressure builds into the region in the wake of the cold
front Saturday night through Sunday with dry weather expected.
Temperatures through the period will near to slightly above
normal with highs in the 60s to around 70 degrees and lows
generally in the 40s.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
MVFR to IFR CIGS, with MVFR VSBYs at times in light rain,
overnight into Monday morning, improving to VFR by midday
Monday.
Weak surface wedge of high pressure over the western and central
Carolinas and CSRA, with patches of light rain across the region.
Widespread MVFR CIGS in place over our forecast area (FA), with
IFR CIGS still confined just to the NW and N of our TAF sites
across NE GA and upstate SC. Frontal boundary back to our NW
will move through Monday and scour out the wedge and low cloud
cover. In the meantime, patches of light rain expected through
early Monday morning, with band of IFR CIGs progressing through
the FA as well,along with periods of MVFR VSBYS in light rain
and/or fog also possible at times late tonight and early Monday
morning. Conditions are expected to improve to VFR by midday
Monday.
EXTENDED AVIATION OUTLOOK...Dry high pressure is generally
expected to preclude aviation concerns during the outlook
period.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Grand Forks ND
919 PM CST Sun Nov 12 2017
.UPDATE...
Issued at 919 PM CST Sun Nov 12 2017
No updates needed.
&&
.SHORT TERM...(This evening through Monday)
Issued at 247 PM CST Sun Nov 12 2017
Temps are the main issue. Lower clouds in NW MN slowly clearing
eastward. Meanwhile high and mid clouds moving east and entering
NE ND. In general model RH progs have these handled pretty well.
In addition a band of low level RH from west central MN into
central/NW ND is lifting back north. It is very thin in nature in
E ND but more expansive in NW ND. HRRR has this band lifting north
into DVL basin this late aftn/eve, then moving north. Fog in NW
into central ND spreading north and should remain west of the
fcst area. However HRRR and other various short range models
indicate some fog possibly affecting far NW fcst area. Main focus
though is west of our fcst area.
How much fall in temps tonight in NE ND and far NW MN tonight? Low
level cloud cover going away but high/mid clouds moving in. Light
south wind. Should drop into the teens in the snowcover area
should occur but otherwise not a huge fall off tonight as warm
advection gets going in the low levels.
Monday will see mid/high level moisture moving through the area
and exiting the east. Warmer air moves in...with near 32F for
highs in NE ND to low 40s in non-snow areas.
.LONG TERM...(Monday night through Sunday)
Issued at 247 PM CST Sun Nov 12 2017
By Tuesday, a ridge aloft brings temperatures rebounding to near
normal values, with highs in the 30s to 40s and lows generally in
the 20s. Warming will be most dominant for areas without remaining
snowpack, generally along and south of the Highway 200 corridor. For
Tuesday night through early Wednesday, precipitation chances return
along and behind a cold front pushing across the Dakotas toward the
Great Lakes. Most model guidance suggests that this will be realized
mainly as light scattered cold rain, except for locations in
counties along the international border that could see light snow
mix in overnight and into Wednesday morning. For Wednesday, drier
high pressure builds through with a significant cooldown to highs in
the 20s to lower 30s.
Late in the week, the next hybrid low pressure system brings
precipitation chances as it pushes east from the Northern Plains to
the Great Lakes. Precipitation chances develop Thursday afternoon
and night, with better chances across the forecast area on Friday.
At this point, there is poor model confidence in the available
moisture content, so will not speculate other than to say snow
chances exist, especially for Friday in Minnesota. However there is
a signal for stronger winds as a low level jet moves through the
area Thursday night through Friday night, so the potential for
stronger winds coinciding with snowfall will need to be monitored in
the upcoming days.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 648 PM CST Sun Nov 12 2017
There are still MVFR clouds at KTVF and KBJI, and it is not
looking like they will move anywhere any time soon. May have to
linger them longer into the night. So far the fog has stayed to
the west of KDVL, but will have to monitor to see if it expands
back into the area tonight. Light winds continue.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Godon
SHORT TERM...Riddle
LONG TERM...BP
AVIATION...Godon
Area Forecast Discussion
National Weather Service Goodland KS
440 PM MST Sun Nov 12 2017
.SHORT TERM...(This evening through Monday)
Issued at 154 PM MST Sun Nov 12 2017
Once again main issues to address will be onset, location and
coverage of stratus and fog. Morning upper air soundings, surface
observations, and satellite showing a moist air mass remains to our
and southeast. This has been the same air mass that has been over
and near the area since the end of last week.
Currently lee side trough is developing as surface ridge has pulled
to the east. Tightening gradient and pressure falls seen on analysis
and captured by the model output. This is going to cause breezy
conditions over the western third of the area. This strengthening
southerly flow will pull the saturated air mass back into the region
during the night. Through the day the guidance has shown a little
tendency to start development a little further west. Hrrr and Rap
have been doing the best recently have caught onto this.
With latest trends have adjusted fog west through Monday morning
from earlier thoughts. Wherever this forms, it will likely become
dense since the air mass has not changed. Evening shift will have to
pin this down. Fog looks like it dissipates by late morning.
However, stratus looks to hang into the afternoon. Even with stratus
hanging on longer today, temperatures rebounded nicely. So kept the
temperatures near the blend except for the far west which has shown
a tendency to be too cool in this pattern.
.LONG TERM...(Monday night through Sunday)
Issued at 145 PM MST Sun Nov 12 2017
Progressive pattern in place as shortwave troughs move over an
upper ridge anchored over Mexico/southern Plains. As a result, no
major weather impacts are anticipated. The only mention of
precipitation will come on Friday, with a cold front bringing a
slight chance for rain showers. Friday may also be windy behind
the front. The rest of the period is dry. May see a little fog in
eastern areas Monday night/Tuesday morning with lingering moisture
associated with the current air mass.
Temperatures on Tuesday will be much above normal, return to near
normal on Wednesday behind a front, slightly above normal on
Thursday, slightly cooler on Friday behind the next front, then
near normal next weekend. Normal high temperatures for this time
of year are in the lower to middle 50s and normal low temperatures
are in the upper 20s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 440 PM MST Sun Nov 12 2017
For KGLD and KMCK, another difficult forecast pinpointing arrival
and departure of stratus and fog this evening through Monday
morning.
For KGLD currently have sub vfr conditions impacting the terminal
around 05z and continuing through 16z with winds from the
southeast to south at 8 to 14kts. After 17z vfr conditions return
with winds from the southwest around 10kts.
For KMCK have sub vfr conditions at the terminal in the 09z-20z
timeframe with winds from the southeast to south 10kts or less.
After 21z vfr conditions return with winds from the south near
10kts.
Updates to the forecast(s) for one or both terminals likely during
the evening as conditions warrant.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...024
AVIATION...99
Area Forecast Discussion
National Weather Service Wilmington NC
902 PM EST Sun Nov 12 2017
.SYNOPSIS...
A cold front will bring showers tonight and into Monday morning.
Canadian high pressure will slowly build across the Carolinas
in the wake of the front. Temperatures will be below normal
early in the week, then recover to seasonable levels late week.
Below normal temperatures will return with the passage of a strong
cold front late next weekend.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 900 PM Sunday...Clipper system over the Ohio Valley will
move rapidly east and offshore during Mon. System will be
followed by cool and dry Canadian high pressure. Guidance not
in the best of agreement regarding POPs or QPF for this event
with a drier GFS contrasting with a wetter solution offered by
the ECMWF and NAM.
Leaned on the wetter solution for the NW corner of the Forecast
Area with the highest confidence in measurable rainfall, up to
categorical POPs. As the showers pivot toward the coast
overnight and Mon morning, the higher resolution models are
kind of all falling on the band wagon with the risk for rainfall
shrinking from S to N as the robust mid-level shortwave begins
to weaken and lift out to the N. Given the short duration of
meaningful moisture, and the residual dry layer below 1 kft, will
keep QPF amounts light, around a tenth of an inch or less.
In the wake of this system, showers will end and a modest surge
of dry and cool air will follow. Even with thick clouds giving
way to increasing sunshine from W to E on Mon, highs will be no
higher than the upper 50s and lower 60s.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 300 PM Sunday...Shortwave over New England at the start
of the period will exit to the northeast Mon night. This
transitions the mid-level pattern over the Carolinas back to
more progressive or zonal flow. Meanwhile, at the surface,
Canadian high over the Ohio Valley at the start of the period
will slowly drift east, ending up over New England by the end of
the period. This will maintain northerly flow at the surface
while aloft the flow will be out of the west-northwest.
Precipitable water will remains under half an inch through the
period which will keep the region dry. In fact other than some
occasional cirrus skies will remain cloud free. Northerly flow
will help keep temperatures a few degrees below climo with highs
in the lower 60s and lows in the upper 30s to lower 40s. Tue
night could see typical cold spots dip several degrees lower as
radiational cooling will be more effective.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 300 PM Sunday...Weakening surface high pressure on Wednesday
to give way to a cold front and new high Thursday night into Friday.
With little to no moisture flux ahead of the boundary and zonal flow
aloft expecting no weather with FROPA. So weak and short-lived will
be the cold advection associated with the front that Friday`s highs
will be slightly warmer than Thursday. High pressure moves offshore
Friday night into Saturday not only strengthening the warm air
advection but also introducing healthy moisture advection. Healthy
cold front to arrive Saturday night or Sunday to bring some rain
chances, though overall model consensus is that QPF prospects will
be minimal.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 00Z...Only moderate confidence with respect to ceilings
and visibilities overnight, as well as the timing of precip, if
any. Models are not in good agreement, with one model taking us
down to LIFR. Think we will probably see IFR conditions, but
hopefully visibilities will remain 2SM or better. The HRRR model
depicts a narrow band of precip, associated with a weak cold
front. The precip should reach the western terminals by 10-12Z.
Look for conditions to improve during Monday morning, with MVFR
conditions expected by afternoon at the latest. Northerly flow
through the forecast period.
Extended Outlook...VFR tempo SHRA/MVFR/IFR Mon. VFR Tue-Fri.
&&
.MARINE...
NEAR TERM /THROUGH MONDAY/...
As of 900 PM Sunday...ENE to E winds of 5 to 15 kt will back to
the N around sunrise as a cold front moves offshore. There will
be a modest cool and dry northerly surge in the wake of this
system with Canadian high pressure slowly building toward the
waters beginning Mon. The pressure gradient will begin to tighten
on Mon and this will increase wind speeds to 15 to 20 kt by/during
the afternoon. Seas will respond, building from 2 to 3 ft tonight
to 3 to 4 ft Mon afternoon with some 5 ft seas late across the
outermost waters.
SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 300 PM Sunday...Northerly flow will remain on the high
end of the 15 to 20 kt range through the period. High pressure
over the Ohio Valley at the start of the period will shift east,
moving over New England as the period ends. The high building
down the coast will help keep the gradient pinched through Tue
night, maintaining speeds approaching 20 kt. Seas 3 to 4 ft with
occasional 5 ft Mon night will increase in response to extended
period of stronger northeast flow. Seas 4 to 5 ft will become
more common Tue with potential for widespread 5 or 6 ft seas and
the appropriate headlines late in the period.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
As of 300 PM Sunday...High pressure centered just west of the
waters to bring a moderate northerly flow on Wednesday. This
flow weakens Wednesday night into Thursday as the high
dissipates. A new center of high pressure becomes established
well to our north by Friday keeping a northerly component
dominant, though NW to NE all seem possible depending on the
shape and positioning of the high. No advisories are planned
through the period.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
NEAR TERM...REK/RJD
SHORT TERM...III
LONG TERM...MBB
AVIATION...DL
Area Forecast Discussion
National Weather Service Lincoln IL
908 PM CST Sun Nov 12 2017
.UPDATE...
Issued at 906 PM CST Sun Nov 12 2017
The main issues tonight center on the timing and coverage of
clearing, and the subsequent formation of dense fog. Fog as
actually already started to form under the stratus layer, mainly
north of a line from Champaign to Lincoln to Peoria. Utilizing
timing tools on the satellite loops shows the clearing line may
reach Peoria by 330 am, I-55 corridor by 7-730am, then down to
I-70 by early afternoon. However, HRRR updates are indicating a
blanket of stratus clouds could remain across all of our forecast
area into Monday afternoon. Not ready to shift that far toward
slowing the clouds, so have trended slower based on satellite
trends. The last couple of runs of the HRRR has also reduced the
coverage and eastward extent of dense fog. Have expanded Patchy
Fog to cover the current foggy areas, and limited the Areas of Fog
to NW of the Illinois river, where HRRR still focuses thicker fog.
Can`t rule out the possible need for a dense fog advisory NW of
the IL river, but confidence is not high enough to issue that with
the evening update.
Clearing could help low temps reach or forecast lows in the NW
counties, but the delayed clearing along and south of I-72 tonight
will create warmer lows there. Have increased low temps across the
south by several degrees.
The remainder of the forecast looks on track. Updated forecast
info is already available.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 316 PM CST Sun Nov 12 2017
Short-wave trough evident on 20z/2pm water vapor imagery over
northeast Illinois will track into Ohio by this evening. Synoptic
subsidence in the wake of the wave will lead to clearing skies
tonight:however, it appears this will be a slow process. Latest
visible satellite imagery shows the back edge of the low cloud
shield just now advancing east past Des Moines, Iowa. Based on
satellite timing tools, clearing will not arrive in west-central
Illinois until around midnight...and may not reach the Indiana
border until closer to daybreak. Once skies clear, the potential
for fog exists overnight thanks to very light winds and a moist
boundary layer. HRRR has been consistently showing widespread fog
along/west of the Mississippi River tonight...as has been trending
further east into central Illinois with subsequent runs. Have
therefore decided to include patchy fog in the forecast after
midnight along/west of a Champaign to Shelbyville line. With low
temperatures bottoming out in the upper 20s and lower 30s, there
could potentially be a few slick patches on sidewalks and
bridges/overpasses for the Monday morning commute. Once any early
morning fog dissipates, mostly sunny skies will prevail with high
temperatures climbing into the middle 40s.
.LONG TERM...(Monday night through Sunday)
ISSUED AT 316 PM CST Sun Nov 12 2017
Another mild and dry day will be on tap for Tuesday, with highs
reaching the upper 40s and lower 50s. The next approaching storm
system will come into the picture Tuesday night into Wednesday as
a short-wave trough and its associated cold front quickly swing
through the region. All models show FROPA around midday on
Wednesday, so have continued to focus highest PoPs late Tuesday
night into Wednesday morning. With modest MUCAPE values of
100-200J/kg in advance of the front, have included a slight chance
for thunderstorms across the western two-thirds of the KILX CWA
late Tuesday night. Once the front passes, rain chances will
quickly diminish from west to east by Wednesday afternoon/evening.
Dry conditions will prevail on Thursday before the mid-week
frontal boundary returns northward as a warm front Thursday night.
Model consensus keeps the area largely dry until late Thursday
night when showers and perhaps a few thunderstorms develop along
the advancing boundary.
Big questions still remain for the end of the period...with the
12z Nov 12 GFS continuing its recent slowing trend and the once
consistent ECMWF now slowing its solution by nearly 12 hours. The
latest GFS features an area of low pressure tracking out of the
Plains into southeast Wisconsin by 00z Sat...while the ECMWF takes
a similar track with the low arriving in southeast Wisconsin by
12z Sat. Both solutions place central Illinois within the warm
sector of the system Friday and/or Friday night...with the
potential for thunderstorms. Given considerable model spread, have
limited slight chance thunder to mainly during the day
Friday...lingering across east-central Illinois into Friday
evening. This obviously may need to be adjusted if the slowing
trend continues.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 559 PM CST Sun Nov 12 2017
IFR/MVFR clouds will continue through the evening, as a clearing
line slowly approaches central Illinois from the west. The center
of the upper level low has shifted into far western Indiana, and
subsident air flows have started to increase. The subsidence has
shut down all precip, but has also set up an inversion that could
trap the low stratus clouds a bit longer than the models want to
clear it out. Have slowed the clearing by an hour or two, but that
may not be enough. Depending on clearing timing and coverage,
dense fog could develop from west to east in the wake of the
clearing. Have introduced LIFR fog at PIA for now, but HRRR is
showing much more widespread VLIFR conditions as far east as DEC.
Will monitor cloud trends closely for fog potential.
Winds will be a non-factor to aviation, other than to be favorable
for dense fog formation.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Northern Indiana
831 PM EST Sun Nov 12 2017
.SYNOPSIS...
Issued at 825 PM EST Sun Nov 12 2017
A mixture of light rain and snow will shift east out of the area
well before sunrise. The precipitation may end as a brief period
of freezing drizzle east of Interstate 69. and possibly a touch of
freezing drizzle will quickly move east by midnight. Lows tonight
will be in the upper 20s and lower 30s. It will be dry with a
warming trend Monday and Tuesday as high pressure settles over the
area. Highs will reach into the upper 40s and lower 50s by
Wednesday. Additional rain showers, with even a possible
thunderstorm, will move through on Wednesday as a cold front
sweeps through the area. Yet another system will bring more rain
on Friday.
&&
.UPDATE...
Issued at 823 PM EST Sun Nov 12 2017
Updated grids to speed up departure of precipitation, add more of
a rain/snow mix with temps falling and surface obs and scattered
reports showing snow at several spots. Back edge of precip was
moving along at a decent clip, with HRRR showing everything
clearing near/just prior to 6Z. Have sped things up as a result
and may not be fast enough.
Still a chance of precip ending as some freezing drizzle in
eastern areas as low level lift continues but ice production lost
aloft.
&&
.SHORT TERM...(This Evening through Monday)
Issued at 405 PM EST Sun Nov 12 2017
Ramping height falls centroid to 80-90 m/12 hours through the
Ohio Valley through 06 UTC to hasten cyclogenesis with northern
wave moisture orphaned along with further whittling away of warm
Tw layer aloft. This will allow transition back to rain/snow mix
through the evening hours. Later tonight as primary mid level
shortwave moves eastward into the Lower Great Lakes, lagged
moisture depth to remove ice nucleation with precipitation
potentially ending as brief period of light freezing rain/drizzle.
Notable downtrend on prior enhanced shortwave cusp over northern
IL/Quad Cities region indicative of these trends as well. Overall
light qpf/high evening/early night pops wending west to east with
only low/dwindling pops beyond 06 UTC east of I-69. Dry conditions
Monday along with lack of strong cold air advection and at least
partial midday/afternoon insolation to allow surface temps to
embark on moderation trend.
&&
.LONG TERM...(Monday Night through Sunday)
Issued at 405 PM EST Sun Nov 12 2017
Good agreement with respect to continued moderation with high
belted partial ejection of northeast Pacific system into
Ontario/western Upper Great Lakes by midweek. Strong height falls
centroid in excess of 100 m/12 hrs along with low level jetlet
moving from northern MO eastward through central IL/central IN along
with higher pool of mid level lapse rates sufficient for a slight
chance mention of thunderstorms. With respect to early weekend
system, model blends and signals continue to point at
warm/convective system, though varying degree of timing and
strength. At some point thunder may need mentioned with this system
as well, but for now with many variables/lower confidence with defer
for now and continue to assess with time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 615 PM EST Sun Nov 12 2017
The discussion for the 18Z TAFs suggested deteriorating
conditions are likely for the overnight hours. The latest data
supports this thinking and thus our 00Z TAFs introduce a period of
IFR conditions.
Satellite and radar imagery depicts the back edge of precipitation
moving over SBN at this hour. Behind this, observations show
ceilings falling to IFR conditions; something guidance is a bit
slow on. This area of IFR ceilings ends near Madison, WI, at this
time. Therefore, we are led to believe MVFR conditions can return
early Monday morning at SBN.
FWA will face precipitation for the next several hours before the
back edge of precipitation lifts out. A few snowflakes can mix in
with rain, but we expect rain to be the dominant precipitation
type. At the time of this writing, FWA is reporting a temperature
of 35F. By the time this activity exits, we have a forecast
temperature of 34F. Then, we expect IFR conditions to unfold for
a time.
At FWA, we played the 12Z forecast ceilings a bit conservative,
but there are some solutions that suggest ceilings could be VFR.
At this time, we will pass this off to the next team to monitor.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...Fisher
SYNOPSIS...Murphy/Fisher
SHORT TERM...Murphy
LONG TERM...Murphy
AVIATION...Brown
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Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
932 PM CST Sun Nov 12 2017
.UPDATE...
932 PM CST
The main concern tonight is the threat of dense fog development
overnight into Monday morning.
At the moment skies remain cloudy across the area. However, the
back edge of the cloud cover is now beginning to approach north
central IL around Rockford. Expect this area of decreasing clouds
to continue towards the Chicago region by around 1 am. Surface
high pressure is expected to build over the area overnight, and
the associated light winds should allow temperatures to drop into
the upper 20s. Given the ample low-level moisture from todays
rain and snow, it appears likely that once the cloud cover clears
dense fog will develop overnight across north central IL. For this
reason, I plan to issue a dense fog advisory for north central IL
through Monday morning. If the fog develops farther west and
south, this advisory may need to be expanded later.
Some minor glazing may also occur with this dense fog tonight as
temperatures drop into the upper 20s. As a result, this could
result in some slippery conditions early Monday morning. The fog
should dissipate by midday.
KJB
&&
.SHORT TERM...
117 PM CST
Through Monday...
Precipitation will exit to the east this afternoon as our compact
and fairly potent upper wave continues into the Ohio valley.
Biggest question for the night is how quickly clouds will clear.
We are seeing a steady erosion of the lower clouds which linger
behind the higher precipitation-producing cloud shield. Light
winds with the high moving in and some recent precip may result in
a little fog. RAP does suggest a gradual thinning of the cloud
shield which may slow some at night, so will continue the general
clearing trend.
Monday looks like one of our nicer days of the week after a gray,
cold, and damp weekend. High pressure across the upper midwest
will become centered across northeast Illinois by Monday mid to
morning before shifting to the eastern Great Lakes region. This
should result in sunshine, light winds, and warmer though still
seasonally cool temperatures. Highs will reach the lower to mid
40s. As the high shifts east Monday afternoon, some increase in
higher clouds is expected.
KMD
&&
.LONG TERM...
211 PM CST
Monday night through Sunday...
High pressure expected to still be in place at the start of the
period, but will shift east Monday night into Tuesday. Southerly
flow/WAA will support continued warming trend with highs in the
upper 40s expected Tuesday. However, sky cover will increase
during the day Tuesday ahead of the next system to affect the
region. Next chance of precip arrives Tuesday night into Wednesday
with the approach of a deeper trough and surface trough/front.
All rain expected, and with increasing WAA and instability, slight
chance thunder wording still seems reasonable. Some slight and
brief cooling expected behind this system but once again only
brief, as WAA ramps back up in advance of the next system.
This system looks to arrive late in the work week into the early
part of the weekend. There are still some timing and placement
differences with this anticipated system, however, wet conditions
appearing likely for most locations within the CWA during this
time. Confidence with overall thunder trends still low. However,
did add slight chance thunder mention Thursday night into Friday.
It`s conceivable that at least a narrow moisture/instability axis
could be in place ahead of the strong/dynamic system, with thunder
a definite possibility. Will need to monitor the possibility for
more robust development somewhere in the region, given the
potential strength of the system. Anticipate colder air to move in
behind this system into next weekend.
Rodriguez
&&
.AVIATION...
For the 00Z TAFs...
530 pm...Main forecast concerns are cigs/vis/drizzle this evening
and then fog again Monday morning.
Cigs have continued to lower into ifr for many locations late this
afternoon with visibilities also lowering into ifr west of the
Chicago terminals. This area of lower cigs/vis will slowly work
its way southeast over the next few hours. Ifr cigs will slowly
lift into mvfr later this evening and scatter out as the back edge
of the cloud cover...currently from eastern WI to eastern IA...
moves across the area. Some patchy drizzle will also be possible
with the ifr cigs this evening.
Once skies clear...temps will likely drop to the dewpoints and
then continue falling by morning with fog developing...mainly west
of the Chicago terminals. Its possible some dense fog may develop
over northwest IL including rfd but confidence is low. Trends will
need to be monitored for fog potential further east for Monday
morning.
Northwest winds 6-9kts this evening will slowly diminish overnight
and turn more westerly Monday morning and then shift southerly
Monday afternoon...but speeds well under 10kts as high pressure
moves across the region. cms
&&
.MARINE...
211 PM CST
With a relaxed gradient in place, relatively lighter winds have
been in place today. Expect this overall trend to continue into
Monday with the arrival of high pressure. This will change going
into the middle part of the week as winds turn southerly and
increase ahead of the next system to affect the region. The
strongest southerly winds during this time expected to be Tuesday
night. Expect winds to mainly stay at or below 30 kt, however,
will need to monitor the possibility for at least a small window
of gales. Winds diminish after this system departs, but will once
again see an increase by late in the work week. Still some likely
variability with the forecast in the coming days, but at this
time, guidance indicating the possibility for higher end gales.
Rodriguez
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
533 PM CST Sun Nov 12 2017
.Updated for 00Z Aviation Discussion...
Issued at 522 PM CST Sun Nov 12 2017
&&
.SHORT TERM...(This evening through Monday)
Issued at 300 PM CST Sun Nov 12 2017
As surface ridging builds in from the west, we have been slowly
eroding away the clouds. Question for this evening with these clouds
is where does the west edge set up. The HRRR had been showing the
west edge setting up from Mille Lacs to the west of Eau Claire
through the night, but current satellite trends would support these
clouds getting east of the MPX area, meaning mainly clear skies for
us tonight. That may sound great, but with the surface ridge axis
overhead and dewpoints this afternoon in the upper 20s, we will have
to watch for the threat of seeing fog/low stratus develop tonight
across eastern MN into western WI. Though skies will be clear, lows
should not get too carried away tonight for a couple of reasons. For
one, dewpoints currently in the mid/upper 20s will help keep lows
from falling much below the mid 20s, while return flow will be
getting going tonight in western MN, where temperatures will likely
start rising before sunrise.
Monday, no precip is expected, though a weak short wave passing in
zonal flow will result in a mostly cloudy day thanks to its
associated mid/upper clouds. As the high moving through tonight
moves into the Great Lakes, increasing southeast winds through the
day will help push highs back up into the upper 30s in northwest WI
to near 50 out in southwest MN, which is pretty close to normal for
the time of year.
.LONG TERM...(Monday night through Sunday)
Issued at 300 PM CST Sun Nov 12 2017
Not much has changed in the general thinking for the extended,
with systems passing through Tuesday evening and again
Friday/Friday night. Tuesday will be the warmest day before the
cold front comes through, with a brief cool down Wednesday before
getting back into WAA Thursday. System for the end of the week
looks to deepen significantly into a "Gales of November" type
system for the Great Lakes this weekend, but locally looks to
bring mainly rain on Friday, followed by strong northwest winds
Friday night into Saturday. We will see a quick cool down behind
this system for next weekend, but temperatures look to moderate
again as we head toward Thanksgiving.
Though our warmest day, Tuesday won`t exactly be the nicest day of
the week. Both the GFS and NAM support dense low stratus the
entire day, while even through Tuesday night they lack moisture
above about 5k feet, which means any precip we see starting late
Monday night and lasting through the fronts passage would be in
the form of drizzle. Greatest moisture feed and threat for
drizzle/light rain still looks to be found across eastern MN into
WI, which is where highest PoPs continue, especially Tuesday
night, when we will finally get a little added lift from shortwave
coming across the northern Plains that will be catching up to the
front as it is heading out the east end of the MPX area. Tuesday
still looks to very well be the Twin Cities last chance this month
at cracking 50, though if we do it, it will be based purely on
advection, with overcast conditions expected all day. Blended
current SuperBlend with going forecast to pull a degree or two off
our highs for Tuesday, though still be warmer than blended
guidance.
For the end of the end of week system, models agree on a general
idea for large scale evolution, but still differ significantly on
timing of one of those features. Where there is good agreement is
that we will see a northern stream wave go off to our northwest
on Thursday night, which will help push a front into the upper
Midwest. Where differences lie in timing is with a much stronger
southern stream wave that will ride up along this boundary from
the central Plains into the Great Lakes. Our precip chances look
to be tied to the developing baroclinic leaf on the northwest side
of the southern stream wave. The ECMWF is a good 12 hours behind
the GFS with this wave. With either solution we look to get
precip, especially from south central MN up toward northern WI,
but it`s a question of does it come Friday morning/afternoon (GFS)
or Friday night (ECMWF). Though timing differences exist, both
solutions show it being warm enough to where the majority of
precip we see will be rain. Only change made to the SuperBlend was
to boost winds for the whole Thursday through Saturday period.
Saturday looks to have the greatest wind potential with strong
CAA. It`s not out of the question that we see gusts Saturday
between 40 and 50 mph before an approaching high finally knocks
winds down for Sunday.
As we get on to the backside of the low, we will see a quick hit
of cold air, with h85 temps dropping to around -15c Saturday into
Sunday, but with zonal flow/flat ridging building back in for next
week, we will quickly see temps moderate back near to a little
above normal as we work into the week of Thanksgiving.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 522 PM CST Sun Nov 12 2017
VFR conditions tonight with clear skies, light winds, and the
potential for some MVFR/IFR fog north of I-94. High clouds will
move across the region on Monday with southeast winds. Deeper low
level moisture will develop Monday night into Tuesday.
KMSP...
VFR conditions throughout. There is a chance for fog but at this
time did not include it in the TAF. Could see MVFR ceilings
develop Monday night.
/OUTLOOK FOR KMSP/
Tue...IFR/MVFR cigs. Chc -dz. Wind S 5-10 kts.
Wed...Chc MVFR. Wind NW 15G20 kts.
Thu...VFR with MVFR/-RASN possible late. Wind SE 10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...MPG
AVIATION...JRB
Area Forecast Discussion
National Weather Service Paducah KY
807 PM CST Sun Nov 12 2017
.UPDATE...
Issued at 807 PM CST Sun Nov 12 2017
With mounting evidence that we will keep overcast skies over the
entire region into at least Monday morning, have done a major
overhaul to the sky grids and in concert have increased
temperatures through the night. Some modest cold advection will
continue, but looking upstream it will be difficult to get
anything lower than the upper 30s even into the I-64 corridor. Not
sure what to do with the clouds Monday, but for now will just show
gradual clearing after 15Z.
Was hopeful that the 925mb RH forecast from the RAP would pan out,
with its rapid clearing over most of the region beginning around
midnight. The latest RAP forecast holds onto the low clouds
through the night over the eastern third of the area, but still
has the rapid clearing over the rest of the area. Will not be
surprised if this still pans out for most of the area, but those
satellite trends are difficult to discount at this point.
&&
.SHORT TERM...(Tonight through Tuesday night)
Issued at 301 PM CST Sun Nov 12 2017
A weak cold front/surface wind shift was well on its way across
the PAH forecast area this afternoon as a mid level trof axis
approached from the northwest. Lingering pcpn has ended in the
east. Some breaks in the clouds may occur for a few hours this
afternoon, mainly over parts of southeastern MO/western KY, but
should fill back in as the aforementioned trof creates a bit of
lift. Generally light surface winds should be out of the north to
northwest everywhere by around nightfall. As northwesterly flow
aloft and high surface pressure move into our region overnight, a
general reduction in cloudiness is expected to begin. Mon and Mon
night will be mostly clear and relatively cool, followed by a
modest warming trend for Tue/Tue night.
Tue night, another low-amplitude mid level shortwave is progged by
the models to move through the Dakotas and upper Midwest, dragging
a cold front eastward toward the PAH forecast area. As a result,
winds will gradually gain a more southerly component Tue/Tue
night. Clouds are forecast to increase from west to east Tue
night, with an accompanying increase in PoPs for showers after
midnight for most of the region. At this time, indications are
that instability will not be enough for lightning activity before
12Z.
.LONG TERM...(Wednesday through Sunday)
Issued at 301 PM CST Sun Nov 12 2017
Confidence in the Wednesday forecast remains fairly high. The models
are in good agreement moving a front through during the day, with
categorical PoPs for showers maintained, along with a continued
slight chance of thunder. The instability is weak, and difficult to
find until lifting parcels from h8 and especially h750. Mid level
lapse rates aren`t too bad either. The chances will end quickly by
early evening, with mainly dry weather Wednesday night through
Thursday morning. Left a token slight chance in along the TN/AR
border so we don`t discount the GFS completely. However the last few
runs of the ECMWF/CMC are definitely trending dry all areas. In the
afternoon, will maintain a low chance PoP over SEMO, probably not
much until dark as again, the ECMWF/CMC are slower to push the warm
front and associated moisture and lift back northeast into the area.
Thursday night, will gradually spread the chance of showers
northeast across the CWFA, with the front pushing northeast into the
area.
Same timing and confidence problems exist for the Friday through
early Saturday time frame. The 12z ECMWF and UKMET have slowed down
even more, suggesting the front may not move through until early
Saturday. This would leave Friday and early Friday night warm
sector, with lower PoPs in the wake of the warm front. The GFS
remains slightly faster though it slowed as well, as does the CMC
(not as fast). We have seen the EC/UKMET solutions slow down too
much in the past only to speed back up with time. Think a middle
ground approach remains the way to go, with just a trend slower.
Therefore once again, the ridiculous categorical blend PoPs here and
there are simply not appropriate for a low confidence forecast that
could shift 6-12 hours either way Day 6 and beyond, until we get
closer to the event. Therefore just high chance PoPs again Friday.
Went low end likely Friday evening, mainly to collaborate without
being too far off with other offices. Then we taper off PoPs after
midnight Friday night. Saturday through Sunday remain dry and cooler
in the wake of the front. If the slower solutions hold, Saturday
morning may be in question (not dry). The ensemble mean solutions
from the NAEFS, GEFS and ECENS all support not slowing down as much
as the latest 12z EC/CMC models. Temperatures will be highly tied to
how events unfold. So low confidence call here as well. Went close
to persistence and MOS to minimize the sway. We may be looking at
strong convection with the Friday/Friday night system. Still an
awful lot of question marks at this point.
&&
.AVIATION...
Issued at 510 PM CST Sun Nov 12 2017
Post frontal stratus will move from VFR to MVFR through the
evening for KCGI and KPAH, clearing after 06z Monday. A similar
situation will occur at KEVV and KOWB, but have much lower
confidence of clearing during the rest of the forecast period.
At this time, numerical models indicate that there is significant
moisture (greater than 90 percent) in the first 1500 feet agl for
each of the TAF sites. Given the lowered pressure deficits and
mixing in the layer, there is some potential that a low MVFR cloud
deck could persist for all of the WFO PAH TAF sites through
Monday. Do not have high confidence after 08z for cloud forecast.
Will monitor trends during the evening, especially for KEVV and
KOWB.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...DRS
SHORT TERM...DB
LONG TERM...CN
AVIATION...Smith