Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/19/16
Area Forecast Discussion
National Weather Service Albany NY
1054 PM EDT Tue Oct 18 2016
.SYNOPSIS...
A cold front approaching from the Great Lakes will cross the area
tonight into early Wednesday morning. Mainly isolated to scattered
showers will accompany the front. High pressure will build in on
Wednesday, with continued above normal temperatures. Low pressure
is then expected to develop and track northeastward from the Ohio
Valley region into the Northeast Thursday into Friday, bringing
much needed rainfall to much of the area.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Two lines of showers have now nearly coalesced into one. HRRR and
RAP continue to show a general weakening as line heads east. This
theme plays out in the forecast with likely POPS now, tapering to
slight chance overnight as line moves into central part of
forecast area. RAP shows some elevated instability with Showalters
near or just below zero. But activity remains fairly shallow. So,
have eliminated any mention of thunder.
10pm temperatures are remarkably warm with Albany and Poughkeepsie
still at 75. Even higher elevations still in the 70s with PSF at
71. These numbers were running a couple of degrees above trend.
Even so, too early in the night to raise low temperatures.
High temperature records were broken at our three climate sites
this afternoon...Albany (84), Poughkeepsie (84) and Glens Falls
(84).
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
High pressure will build into the region on Wednesday, providing dry
conditions. After some early clouds, increasing sunshine is expected
through the rest of the day. Temperatures will be cooler than
Tuesday, but still well above normal for this time of year with no
significant change in air mass behind the "cold" front. Temperatures
should top out 10-15 degrees above normal with a light W-NW breeze.
Dry conditions will persist Wednesday night, as high pressure
gradually shifts eastward to Maine by sunrise Thursday. Temps will
be cooler than recent nights, although still close to 10 degrees
above normal with increasing clouds.
Conditions should become more unsettled on Thursday, as an inverted
trough associated with developing low pressure across the Ohio
Valley moves into western/central NY. The main focus for low level
convergence will be the surface trough, so based on its forecast
position, areas mainly north and west of east central NY will
experience steady/heavy rainfall. However, there should be enough
forcing for at least some measurable rainfall for much of the area.
Axis of steadier/heavier rain could set up across far NW portions of
Herkimer/Hamilton counties, but there are some differences in
forecast models regarding the exact position. It will be mostly
cloudy and cooler with the clouds and showers around.
A more widespread and steadier rainfall could move into more of the
region Thursday night into Friday, as the low pressure system is
forecast to track NE across Upstate NY. Again there are some slight
model differences in the track, which would have an impact on what
areas receive more rainfall. However, even if the low tracks
slightly farther north, the upper level trough is expected to deepen
upstream, with good moisture transport into our area courtesy of a
strengthening 850 mb southerly jet. GEFS indicating both PWAT and
wind anomalies approaching +2 to +3 std dev. by Friday, with the
potential for a narrow cold frontal rainband possibly providing a
period of downpours. We will have to see how this system evolves
over the next few days, but there at least the potential for some
decent rainfall.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The period will be marked by persistent troughing across the eastern
U.S. This means some precipitation likely and temperatures trending
cooler/colder.
An upper level low cuts off near the forecast area Friday night and
pulls north through the weekend. A surface low will be pulling north
into eastern Canada by Saturday.
Moist cool/cold cyclonic flow around the upper low and surface
system will yield likely POPS across the area on Friday night,
tapering to chance into the weekend. There is the chance for some
snow or rain snow mix across the higher elevations of the
Adirondacks Saturday night through Sunday night. Not expecting any
significant accumulation.
Some differences in the models appear Sunday night with the ECMWF
scooting a clipper system across PA and NYC. While the CWA would be
on the north side of this system, 925mb temps look too warm for any
snow. The current forecast, from the SuperBlend, does not account
for this system keeping POPS dry on Sunday night.
While there are timing differences between the GFS and ECMWF on when
the core of the coldest air resides over the CWA, it is clear that
temperatures through the period will average 5-10 degrees below
normal. Look for high temperatures to struggle to get out of the 30s
across the Adirondacks Saturday-Tuesday.
The latest forecast from the National Hurricane Center on the system
east of the Bahamas calls for an 80 percent chance of development
over the next 5 days. The NHC forecast has the system heading
northeastward out to sea by the end of the week.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Most likely terminals to experience showers tonight are KALB and
KGFL. There have a prevailing MVFR flight category. At KPSF while
can`t rule out a shower, not sufficiently convinced so will offer
no more than VCSH. Shower activity at KPOU looks even less likely,
so no restrictions there.
With exception of POU, expect all terminals to see some IFR BF/FG
overnight with high dewpoints, some showers, and some breaks
developing in the clouds during the pre-dawn hours.
VFR conditions should return quickly between 12Z-15Z/WED with
clearing skies and strong subsidence with the frontal passage.
Outlook...
Wednesday Night: Low Operational Impact. NO SIG WX.
Thursday: High Operational Impact. Likely SHRA...RA.
Thursday Night: High Operational Impact. Likely RA.
Friday: High Operational Impact. Likely RA.
Friday Night: Moderate Operational Impact. Likely SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA.
Saturday Night: Low Operational Impact. Slight Chance of SHRA.
Sunday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
After a day of record-breaking warmth across the region, a cold
front approaching from the Great Lakes will cross the area tonight
into early Wednesday morning. Mainly isolated to scattered showers
will accompany the front. High pressure will build in on Wednesday,
with continued above normal temperatures. Low pressure is then
expected to develop and track northeastward from the Ohio Valley
region into the Northeast Thursday into Friday, bringing much
needed rainfall to much of the area.
Relative humidity values will increase to around 90 to 100 percent
tonight, then drop to minimum values of between 45 and 60 percent
Wednesday afternoon. RH values will increase to around 90 to 100
percent Wednesday night.
Winds tonight will be south-southwest around 10 to 20 mph with some
higher gusts this evening. Winds will shift to the west-northwest on
Wednesday around 5 to 10 mph. Winds will be light and variable
Wednesday night.
&&
.HYDROLOGY...
A cold front moves southeast across the region tonight into early
Wednesday, bringing mainly isolated to scattered showers. Overall,
rainfall amounts through will be light, generally less than one
tenth of an inch, but up to two tenths of an inch across portions of
the western Adirondacks.
Dry weather expected Wednesday into early Thursday morning, before a
developing low pressure system tracks northeast from the Ohio Valley
region, which should bring much needed soaking rainfall to at least
parts of the region Thursday through Friday. Best chance for
appreciable rainfall looks to be for areas north and west of the
Capital District.
The latest US Drought Monitor continues to show drought conditions
have worsen across portion of the area. Precipitation departures
this calendar year are 5 to 15 inches below normal, with the
greatest departures across southeastern parts of the HSA.
As a result, streamflow and ground water levels have been running
well below normal.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...JPV
NEAR TERM...OKeefe/JPV
SHORT TERM...JPV
LONG TERM...OKeefe
AVIATION...OKeefe
FIRE WEATHER...JPV
HYDROLOGY...11/JPV
Area Forecast Discussion
National Weather Service Bismarck ND
934 PM CDT Tue Oct 18 2016
.UPDATE...
Issued at 931 PM CDT Tue Oct 18 2016
Showers have ended, though low cloud cover has pushed further into
the area than previously thought as cooler airmass pushes in. HRRR
has had the best grasp on the progression of this cloud cover, and
it now looks like it has stopped pushing in over the west, though
will continue to push a bit further south over the James River
Valley. Have addressed this in latest forecast.
UPDATE Issued at 629 PM CDT Tue Oct 18 2016
A few light showers continue to linger in weak cyclonic flow over
south central North Dakota into the James River Valley, though
these will continue to dissipate with the lack of daytime heating.
Otherwise, quiet weather will prevail tonight with mostly cloudy
skies north, lesser cloud cover far south.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 113 PM CDT Tue Oct 18 2016
A cold front continues to slowly slide southeast across North
Dakota today. Occasional light rain may be possible along the
front, but the majority of North Dakota will remain dry this
afternoon and evening. Temperatures tonight will fall into the 30s
with a light, but chilly northwest wind.
A cool and mainly cloudy day can be expected tomorrow as cold air
advection behind the front continues.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 113 PM CDT Tue Oct 18 2016
Several weak upper level waves move through the region over the
next several days. Models differ widely on whether or not to
produce any precipitation from these waves. It appears by and
large the majority of the area will remain dry, with some isolated
rain here and there possible.
An upper level ridge moves in by the weekend. This will keep the
weather dry and warm. Temperatures will be above average with
readings in the 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 629 PM CDT Tue Oct 18 2016
MVFR with localized IFR cigs are expected to prevail tonight over
northern North Dakota in the wake of a slowly advancing cold
front. Further south, mainly VFR conditions are expected. By mid-
day Wednesday, most locations are expected to be VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...JJS
Area Forecast Discussion
National Weather Service Denver/Boulder CO
917 PM MDT Tue Oct 18 2016
.UPDATE...
Issued at 847 PM MDT Tue Oct 18 2016
A cold front appears to have moved through Greeley and Longmont
and will make its way into Denver around 04z. Upper trough moving
across srn WY/nrn CO overnight...mainly area of showers will be
north of Denver over Larimer and Weld Counties... although a few
sprinkles will be possible for a short time south towards Denver.
The latest HRRR keeps the main area of showers to the north and
moves it into Nebraska after 09z. Will keep some minimal snow
accumulations in the mountains north of I-70 overnight.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 245 PM MDT Tue Oct 18 2016
Area radars are showing a few showers mostly over Larimer and
northern Weld counties. Models have the upper trough push across
the CWA by Wednesday morning....then strong northwesterly flow
aloft in the afternoon. There is pretty decent upward QG Omega
over the CWA overnight, with the best around 06Z. There will be
pretty decent subsidence in the synoptic scale Wednesday
afternoon. There is a surge of northerly flow for the plains by
late evening. There are north-northwesterlies progged by 12Z
Wednesday morning. North-northwesterlies are progged on Wednesday.
For moisture, it is not great with the most over the mountains and
foothills. The plains will have very little moisture in the lower
levels. After 12Z Wednesday morning moisture decreases for all the
CWA. The QPF fields have some measurable snow in the mountains
over night, with very limited precipitation over the plains. For
pops, there is decent synoptic scale energy overnight, but
moisture is shallow. Will keep the "likely"s over the mountains
and northern foothills, but will lower plains pops in most areas
to 0-20%s. The exception being zone 38 where I will keep,
"chance"s. For temperatures, Wednesday`s highs will be 3-5 C
colder then this afternoon`s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 245 PM MDT Tue Oct 18 2016
Strong ridging over the western U.S. is going to bring a
continuation of warm and dry weather across the northern half of
the state. First off, clear skies and a dry airmass tomorrow night
will produce optimal radiational cooling conditions that allow the
temperatures to drop into the upper 20s and lower 30s across the
plains. A frost advisory may be necessary for that time period,
but it is a marginal situation at this point. Through the end of
the week, temperatures will be gradually warming with high
temperatures over the weekend in the upper 70s and lower 80s.
The next weather maker to affect the northern half of Colorado
will be next Monday night as the upper ridge is forecast to move
eastward with increasing southwesterly flow aloft over the region.
If this pattern comes to pass, the mountains will have the best
chance at receiving precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 847 PM MDT Tue Oct 18 2016
East/southeast winds will transition to north/northwesterly with
the passage of the cold front which may be closer to 04z. Lighter
northerly winds after 09z...with north/northwesterly winds on
Wednesday. VFR conditions...could see a brief period of cigs
070-080 kft agl 04-07z. VCSH at best...likely with or shortly
after the passage of the front.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Cooper
SHORT TERM...RJK
LONG TERM...Dankers
AVIATION...Cooper
Area Forecast Discussion
National Weather Service Billings MT
641 PM MDT Tue Oct 18 2016
.UPDATE...
Quiet weather around the cwa early this evening. Water Vapor
imagery shows shortwave approaching from the west, and there
exists a band of showers approaching GTF-BTM-DLN. Forcing is still
a few hours from reaching our west, so have trimmed back evening
pops based on current radar/satellite trends. For Billings, the
evening should stay dry, with best chance of pcpn between 09-15z,
and feel that we will see some light showers w/ passage of mid
level front, especially as low level downslope winds are not
strong. For the mountains, expect a few inches of snow as the wave
passes, with plenty of instability helping the cause (700-500mb
lapse rates in excess of 7C/KM). Further east, a weak backdoor
front will allow for a shift to light NE winds. This is something
to watch as there is a large area of lower cigs associated with
the cooler airmass just to our northeast. Some lower clouds could
advect into MLS-BHK-Ekalaka late tonight. It is also possible that
fog forms where stratus does not, given dew points in the mid to
upper 30s. Latest HRRR runs have been suggestive of fog in our NE
late tonight. Have raised sky cover and added mention of patchy
fog to these areas after 09z. JKL
&&
.SHORT TERM...valid for Wed and Thu...
The Pacific jet stream to our south is beginning to amplify as
ridging slowly builds up the Western US coast. As this trof pushes
southeast, showers will overspread the region from west to east
beginning tonight as jet-aided divergence crosses the forecast
area overhead. While most locations will see scattered rain
showers, a rain/snow mix possible in the hills above 4000ft and
north and west of Billings overnight. The high elevations above
6000ft in the Beartooths and Big Horns will see 4-6 inches of snow
through the morning with western facing slopes being the largest
recipients of snow. Cloudy conditions will persist through the
early afternoon before slowing clearing up from the west as the
ridge begins to take hold over the area on Wednesday. A few snow
showers could persist in the mountains until 6 pm but conditions
should quickly improve through the remainder of Wednesday night.
Winds will turn southwesterly over the forecast area on Thursday
morning and this will cue a warm up across the region. Weak
downslope conditions will move in and this will help temperatures
climb to around 60 across the forecast area. Lee-side troughing
along the Rocky-Mountain front will strengthen the pressure
gradient across Livingston which will bring an increase in the
winds through the afternoon. Held off on a wind advisory for now
but highlighted these wind concerns in the hazardous weather
outlook. Wind gusts up to 50 or 60 mph are possible late Thursday
afternoon. Currently it looks like these winds will begin to
decrease through Friday morning as the pressure gradient across
our western zones weakens. Dobbs
.LONG TERM...valid for Fri...Sat...Sun...Mon...Tue...
Upper-level ridging should dominate on Friday with dry and warm
weather. Gap winds near Livingston should decrease during the day
as the surface pressure gradient continues to relax.
Models bring a disturbance over central and northern MT on
Friday night. This disturbance could generate a few showers
mainly west and north of Billings.
Ridging should dominate again Saturday and Sunday. Ridge axis
looks to move east of the area early Monday, placing our area
under southwesterly flow aloft. Disturbances propagating in the
southwest flow can produce showers mainly over the mountains on
Monday and then extend to areas east of Billings on Tuesday. 700
mb flow looks southwesterly, which typically results in a local
drying effect near Billings due to downsloping.
Temperatures should be above normal Friday-Tuesday. RMS/BT
&&
.AVIATION...
VFR will prevail over the area tonight. Some showers are
beginning to develop western portions of the forecast area...but
stronger activity is expected to move in from the west yet this
evening, affecting KLVM by midnight. Showers will shift slowly
eastward overnight...reaching KBIL by early Wednesday morning.
This activity will produce localized MVFR conditions over the
lower elevations at times...with associated mountain obscurations
becoming common overnight. Patchy fog is also a concern in eastern
routes...including KMLS and KBHK...in the early morning hours
Wednesday. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
Wed Thu Fri Sat Sun Mon Tue
-----------------------------------------------------------
BIL 040/054 034/060 043/067 045/063 042/065 043/064 044/063
43/W 00/B 10/B 10/B 11/B 11/B 11/B
LVM 034/048 032/058 042/064 042/061 039/065 041/063 042/061
62/W 00/N 11/N 21/B 11/N 12/W 22/W
HDN 037/055 032/062 039/069 043/064 040/066 041/066 042/065
35/W 10/B 00/B 10/B 11/B 01/B 11/B
MLS 036/052 034/061 041/066 044/062 040/064 040/064 042/064
12/W 10/U 10/B 11/B 11/U 01/B 12/W
4BQ 035/050 032/062 039/068 042/065 040/068 041/069 043/068
14/W 10/U 00/B 00/B 11/U 01/B 12/W
BHK 032/049 031/059 037/064 041/061 037/063 038/063 040/063
03/W 10/U 00/B 11/B 11/U 01/B 12/W
SHR 033/050 027/060 037/067 040/065 037/068 039/067 039/065
35/W 10/B 10/B 00/U 11/B 01/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion...UPDATED
National Weather Service Columbia SC
1007 PM EDT Tue Oct 18 2016
.SYNOPSIS...
An upper-level ridge across the area will weaken allowing an
upper-level trough to cross the region Friday through Saturday.
Surface high pressure will be in control of the region through
Wednesday night. A cold front with will move across the area
Thursday night and Friday morning. Cooler and drier air will move
in behind the front for the weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Surface and upper level ridging will continue over the region
tonight. Latest infrared satellite imagery showing clear skies
across the forecast area. Atmospheric moisture is limited and
shallow but patchy fog may develop with strong radiational
cooling overnight. However a 15 to 20 knot low level jet may keep
the boundary layer mixed at times and may lead to patchy stratus.
HRRR indicating some possible stratus clouds may develop but
confidence is low. Lows will be in the upper 50s to lower 60s.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
Dry weather along with well above normal temperatures are forecast
to continue Wednesday and Thursday. An upper-level ridge
entrenched over the Deep South and Southeastern states will begin
to weaken Thursday as a deep trough digs into the Mississippi
Valley. Surface high pressure will also weaken Thursday as a cold
front approaches from the west. With strong insolation and
subsidence...model consensus indicated maximum temperatures above
normal in the mid to upper 80s. Despite strong radiational cooling
at night overnight temperatures above normal in the mid 50s to
lower 60s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Models are in good agreement with approaching upper level trough
crossing the region Thursday night into Friday night. This
progressive trough is forecast to amplify and become negatively
tilted Friday. Models are consistent with subtropical low moving
well offshore to the northeast as the upper trough approaches. A
cold front should move through the region early Friday with cold
advection developing during the day. Moisture appears limited
along the front and mos pop consensus continues to decrease. Have
indicated only a slight chance for showers late Thursday night
into Friday associated with frontal passage and upper trough. The
front may come through dry. Saturday appears dry across the region
with downslope flow. Dry and much cooler...more seasonable weather
is forecast behind the front through early next week as surface
high pressure returns to the region.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
The main forecast issue is the fog threat during the early morning
hours. Low-level moisture has increased slightly and with
nocturnal cooling stratus and fog may developing during the early
morning hours. However, the moisture will remain shallow and a
low-level jet as indicated by model time-height displays should
result in some continued mixing. There was consistency in the MAV
and MET MOS with a period of IFR fog at the river valley terminals
of AGS and OGB. We followed this guidance. The MAV and MET MOS and
crossover temperatures suggested a period of MVFR or IFR fog
elsewhere, but based on the low-level jet and HRRR we maintained a
VFR forecast but confidence is not high because of the mixed
signals in the guidance. Heating and mixing should dissipate fog
beginning around 13z. The pressure gradient will remain weak.
Followed the MAV and MET MOS for the wind forecast with west wind
less than 10 knots.
EXTENDED AVIATION OUTLOOK...MVFR or IFR stratus and fog possible
each morning through Thursday. Restrictions possible in scattered
showers Friday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Grand Forks ND
955 PM CDT Tue Oct 18 2016
.UPDATE...
Issued at 955 PM CDT Tue Oct 18 2016
Coordinated with DLH and BIS to up sky cover thru the overnight
into Wednesday midday for most of the area. Solid cloud mass
moving southeast in cold advection and looks like they will be
thicker and hang around longer than average RH model blends would
indicate.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 248 PM CDT Tue Oct 18 2016
How to handle spotty showers tonight will be the main issue for
the period.
Upper flow is nearly zonal, with several weak shortwaves moving
through. One shortwave was seen on water vapor loop right along
the ND/SD/MN border area, while there is another one evident
further west in central ND. Light showers have continued to
develop and then fizzle out as they move east today, but there is
now an upward trend in Barnes/Cass counties. The RAP and HRRR
develop more shower activity further to the north in the next few
hours as the shortwave over central ND approaches. Will expand the
POPs mention for this evening, but most of the showers should be
done before midnight as the shortwave exits off to the east.
Tomorrow will be quiet with a weak surface high over the region.
As for temperatures, a surge of cold air will begin to move in
from the north overnight, with 925mb temps dropping back below
zero. The northwestern counties will see the brunt of the cold air
advection but also will have some clouds for much of night, so
kept lows near the 30 mark. The southern counties should be a bit
higher in the upper 30s with less clouds but with some mixing
winds and a warmer start. The cool air mass will continue through
Wednesday with highs ranging from the low 40s north to low 50s
south.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 248 PM CDT Tue Oct 18 2016
Thursday through Friday...This time frame should be mainly dry
with a cool Thu followed by a milder Fri as mid level ridging
builds this way. A low POP for some mixed pcpn is included
vicinity of LOW for Thu morning as trough axis swings through that
area near time of min temps. Both the GFS and ECMWF agree on
timing and placement of this feature. The next hint of any more
precip would occur by Fri afternoon owing to weak WAA over mainly
northwest CWA.
Saturday through Tuesday...Still not a whole lot of activity as we
head through the weekend and into early next week. ECMWF brings a
reasonably robust short wave over northern forecast area later
Saturday into early Sunday; GFS solution is more of a slight
flattening of the ridge with much less QPF. Above freezing min
temps and a mild Sunday would make this an all liquid affair. The
ridging still seems to want to hang around into early next week
keeping temps on the mild side of normal, with a more
southwesterly flow leading to a possible showery period at the end
of our time frame.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 648 PM CDT Tue Oct 18 2016
Extensive MVFR cigs in cold advection Devils Lake basin and
northward. Unsure how these clouds will behave as they drop
southeast. Model RH progs indicate increasing moisture in the
925-850 mb layer tonight into Wed morning...whereas most short
range model cloud cover progs indicate deck will not fully drop
southeast. Played it a bit cloudier but for the time being kept
cigs in VFR range all but DVL tonight. Uncertainity with this does
exist.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Riddle
SHORT TERM...JR
LONG TERM...WJB
AVIATION...Riddle
Area Forecast Discussion
National Weather Service Houston/Galveston TX
823 PM CDT Tue Oct 18 2016
.DISCUSSION...
The combination of onshore winds and an increasingly moist airmass
has led to the formation of isolated showers off of the coast
early this evening. Model sounding forecasts show the best
potential off of the coast this evening and into the coastal
counties after midnight. The Texas Tech WRF and the RAP13 both
agree with this scenario while the HRRR has the rainfall potential
increasing over the coastal counties toward sunrise.
Revised the rain chances for this evening and overnight tonight.
40
&&
.PREV DISCUSSION... /ISSUED 622 PM CDT Tue Oct 18 2016/
AVIATION...
Generally VFR conds expected for this evening but clouds are
expected to begin to develop after 06z over the NW-N TAF sites. A
surge of slightly deeper moisture. Could see some showers begin to
develop near KGLS and KLBX prior to sunrise as a narrow convergent
zone develops near the coast. Think potential for showers will
exist on Wed aftn as PW values increase to 1.60 inches. Both the
RAP and the TT WRF show scattered showers across much of SE TX.
Will be watching short term model trends and might be adding a
VCSH with the 03z update. 43
PREV DISCUSSION... /ISSUED 343 PM CDT Tue Oct 18 2016/
DISCUSSION...
Another day of unseasonably warm weather expected tomorrow before
the arrival of the cold front on Thursday. We have already tied a
record this afternoon (GLS) and are close to another (CLL). As it
stands...records most likely to be reached/exceeded tomorrow will
be HOU/GLS. (see below)
No significant changes with the overall forecast as models remain
in fairly good agreement with the upcoming pattern shift. Weaken-
ing/eastward shifting upper ridge will allow for the passage of a
deep longwave trof Weds/Thur. This will then help to drag a long-
awaited cold front into/across the state Thur. The NNW flow aloft
in the wake of the front is then progged to segue into broad upp-
er level ridging by the weekend. Will have to keep an eye on this
pattern as the new week starts as there are hints (via ECMWF) the
ridge will be short-lived with the development/passage of a fair-
ly well-defined shortwave moving in from the CA Baja region. Will
this herald a more active pattern for next week? Long-range progs
from GFS (of a strong upper low/trof deepening just off the sout-
hern CA coast and its subsequent SW flow aloft here) seem to con-
trast sharply with the ECMWF extended patterns (of strong ridging
over the state). Hmmm. Upcoming runs should be interesting. 41
High Temperature Records
TODAY 10/18 WEDS 10/19
CLL 92-2004 97-1921
IAH 96-1895 94-2004
HOU 94-1947 90-2004
GLS 87-2007 86-2004
MARINE...
Tides are still running about a foot above normal. Will probably see
water come up to or slightly over the Highway 87 @ Highway 124
intersection between 5-10pm this evening and again Wed (around times
of the the more significant high tides). Doesn`t appear any other
locations should see any substantial issues.
Southerly to southeasterly flow of around 10-15kt is forecast to persist
for the next couple of days. A cold front will push off the coast on
Thursday, with northeasterly winds increasing to around 20-25kts and seas
reaching 6 to 8 feet in the offshore waters overnight Thursday night.
Winds will gradually shift onshore and weaken as seas slowly subside
throughout the weekend. 11
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 73 92 70 79 55 / 10 20 30 40 10
Houston (IAH) 71 91 71 85 57 / 10 20 30 40 10
Galveston (GLS) 78 87 77 83 65 / 20 30 30 50 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...40
Aviation/Marine...43
Area Forecast Discussion
National Weather Service Lincoln IL
905 PM CDT TUE OCT 18 2016
.UPDATE...
Issued at 902 PM CDT Tue Oct 18 2016
The cold front will continue to make steady progress to the
southeast overnight, with a few light rain showers possible along
and ahead of the front. Have continued with slight chances of rain
for our southeast counties, mainly SE of I-70 as the front
approaches Effingham to Terre Haute at 9pm. Mainly clear skies and
light northwest winds behind the front has allowed Galesburg to
drop to 56 already this evening. Have adjusted low temps downward
a couple degrees for areas NW of the IL river, with less
adjustments in low temps from I-55 and east.
The front is slowing down in its forward progression, which
matches with the HRRR and RAP guidance that shows the front
stalling out along the southern Indiana state border. That will
leave the front close enough that the next shortwave to ride NE
along the front will bring increasing chances of showers in our
forecast area during the day tomorrow, especially tomorrow
afternoon. That is handled well in the current forecast grids.
Updates for the evening with done to low temps, dewpoints,
weather/PoPs, and sky conditions. The latest info is already
available.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 255 PM CDT Tue Oct 18 2016
A cold front will continue to drift south over the forecast area
this evening, with a band of lower clouds just ahead of it...and a
slight chance for rain and thunder in the southeast this evening.
Cooler air filtering in behind the boundary will result in overnight
lows in the 50s north of the I-70 corridor...low 60s south. This
same boundary stalls in the region, near the Ohio River
valley/southern borders of the state later tonight. Small waves
rippling through the region bring a chance for showers along and
behind the boundary through the southern half of the state for
Wednesday. Models differing somewhat with the northern extent of the
showers through tomorrow afternoon before the bulk of the
wave/precip develops for the evening hours.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 255 PM CDT Tue Oct 18 2016
The cold front moving through central Illinois early this afternoon
is expected to slow down as it becomes parallel to the upper level
flow near the Ohio River Valley later tonight. A shortwave, seen on
water vapor imagery approaching the Rockies, is expected to approach
just west of the MS River Valley Wednesday evening. This will be
provide upper level support for showers and t-storms in parts of
central and southern Illinois - mainly south of a Springfield to
Danville line. Many of the models continue to show mainly elevated
storms north of the surface boundary, however south of I-70 CAPEs
are higher and wind shear sufficient for a few storms to become
strong or even severe with hail and wind gusts during the evening.
The GFS and European are similar with the timing and intensity of
the deepening upper level trough as the western shortwave moves east
of the MS River Valley Thursday. The NAM and Canadian are a bit
slower and are holding on to the rain longer into Thursday afternoon-
early evening. Prefer the quicker GFS/European blend and will only
hold on to lingering showers near the Indiana border Thursday
afternoon.
High pressure and a northwest upper level flow will allow
temperatures to drop toward more seasonable levels for Friday and
through the weekend. Will hold off on mentioning patchy frost for
Friday morning north of I-74 with temperatures in the upper 30s and
northwest winds around 5-10 mph.
After several days of dry weather through the weekend and into early
next week, the next shot at showers may be next Tuesday. The GFS has
warm front draped across parts of central IL. However, there is
fairly low confidence with this solution since the GFS Ensembles are
all over the place, and the inconsistent European is showing dry
weather. Thus, will only introduce a chance of showers near the
potential frontal boundary location around the Peoria area and to
the northwest.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 647 PM CDT Tue Oct 18 2016
The cold front has pushed south of all the terminal sites, and NW
winds have developed in its wake. Gusts have not been showing up
in the OBS so far behind the front, and expect that trend to
continue the rest of the night. High pressure building into
Illinois over the next 24 hours will set the stage for wind
directions to gradually shift from NW to N and then NE by sunrise.
Winds should remain NE through the day tomorrow, with speeds
generally remaining less than 10kt.
The frontal boundary will stall out in the Ohio River Valley, but
a weak shortwave lifting NE along the front will bring chances of
showers into SE IL. DEC and CMI may see a stray shower nearby
later in the afternoon, and thunder could also develop, but we just
added a VCSH late in the TAF period for now. VFR conditions will
prevail for the majority of the next 24 hours, barring any storms
at a terminal site.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...Miller
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
657 PM CDT Tue Oct 18 2016
.SHORT TERM...
140 PM CDT
Through Wednesday...
A cold front continues to push across the region this afternoon,
and stretches from roughly Gary through Pontiac at 18Z. Out
ahead of the front, temperatures in the upper 70s with dewpoints
in the mid 60s will contribute to close to 1000 J/kg MLCAPE by mid
afternoon, so cannot rule out a shower or isolated thunderstorm
developing but better chances will be off to our east where there
is very modest upper support associated a sheared shortwave
pushing across the Great Lakes. Behind the front, winds are
turning northwest and easing while skies are clearing out. Latest
runs of the RAP and HRRR continue to suggest a lake breeze will
form and push inland across NW Indiana and a little into Cook
County mid to late this afternoon which will hasten temperatures
dropping back through the 60s for those areas. Otherwise, expect
quiet weather this evening and overnight as high pressure builds
towards the mid/upper Mississippi Valley.
High pressure will continue to dominate most of the day Wednesday
providing light northeast flow and primarily dry conditions.
Despite the cold frontal passage, we will continue to experience
above normal temperatures Wednesday with mid to upper 60s north of
I-80 and low 70s along and south of I-80. An upper level
disturbance currently digging across the Inter-mountain West is
progged to lift across the central plains Wednesday. Weak mid
level height falls will begin to overspread the local area by mid
to late in the afternoon with increasing mid and high clouds.
Models do generate some QPF up through roughly the I-80 corridor
by 00Z tomorrow evening, though soundings show dry air persisting
below 700mb. Could be some high-based light showers or sprinkles
moving up from the south into the local CWA, but better chances
for showers will be closer to the baroclinic zone stretching from
downstate Illinois into southern/central Indiana.
Deubelbeiss
&&
.LONG TERM...
210 PM CDT
Wednesday night through Monday...
A transition back to more seasonal weather is on tap for the extended
period.
NAM/GFS both depict fairly strong frontogenesis with the cold
front Wednesday night in the clash between our anomalously warm
airmass of late and the colder continental air arriving from the northwest.
This will be coupled with strengthening low pressure from the
left rear quadrant of an upper level jet stream and should result
in an increasing precipitation shield across the region Wednesday
night. At this point the better co-location of forcing and
moisture will remain draped south and east of our area, but there
should be enough for some bands of lighter to even moderate rain
across the I-55 corridor southeastward and possibly even extending
farther into northeast IL. This forcing continues through the day
Thursday with the jet in the region, an approaching pacific
shortwave trough axis and a strengthening surface low continuing
the deformation precipitation across much of Indiana with some
lower chances across Northwest Indiana. Expect more clouds than
sun.
While colder air slowly bleeds in during the day Thursday, a secondary
surge of colder air will be shoved southeastward by a portion of
the Canadian upper trough will reinforce the changing airmass.
Models depict this will be a largely dry frontal passage, but do
portray some lake effect rain showers across northwest Indiana.
The convergence signal is somewhat weak and progressive and
moisture is but the thermodynamic signal is robust to suggest
there will be some lake effect showers with fairly high
confidence, but lowered confidence on how widespread and how long
lasting. Areas away from the lake will have sunshine but cool
conditions and area wide highs in the 50s, some low 50s north.
High pressure returns Friday night and Saturday which look dry,
in spite of the EC painting some light precip along an elevated
warm frontal boundary as the high approaches. An upper wave will
pass by to our north on Sunday which will initially lead to
slightly warmer conditions, though there are better indications of
a backdoor cold front sometime later Sunday into Monday. The front
holds off till after sunset on the GFS, midday/afternoon on the
EC/GFS. This will setup a frontal zone across the local area which
may serve as a focus for increased precipitation chances Tuesday
or into the middle of next week.
KMD
&&
.AVIATION...
For the 00Z TAFs...
Concerns with the aviation forecast are east-northeast winds on
Wednesday afternoon possibly reaching 8-10 kt, at least
occasionally, and the chance for light rain Wednesday evening.
A cool front that went through earlier had brought northwest
winds, but fairly weak. These will become light and variable
within the next hour and persist through Wednesday morning. In the
afternoon, a lake breeze or at least winds off the lake are
likely. Confidence on speed not exceeding 7 kt is medium. Mid-
level cloud cover will thicken late in the day into the evening. A
dry low-level may prevent any light rain from reaching the surface
and have leaned that way in the ORD TAF right now.
MTF
&&
.MARINE...
210 PM CDT
Today`s cold front has cleared the lake as low pressure across
northern Quebec exits the region. High pressure across the
Canadian Rockies will creep southeastward into the upper Midwest
and plains region over the next few days. Meanwhile, and area of
low pressure currently stretched across the Ohio valley and into
the southern Plains will lift northeast toward the latter half of
the week. In between these two systems a cold front will pass
south across the lake Wednesday night with a tightening pressure
gradient resulting in gusty north winds Thursday. With the
persistent north winds behind the front, expect waves to build on
the south end of Lake Michigan and result in dangerous conditions
for small craft Thursday into Friday. The high will weaken some
Friday as the low continues to strengthen across the northeastern
United States Friday. The high pressure ridge will move east of
Lake Michigan Sunday and will result in a shift to southerly winds
briefly before a backdoor cold front results in a shift back to
northeast winds.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Mobile AL
735 PM CDT Tue Oct 18 2016
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...
19/00Z issuance...VFR conditions will generally prevail through the
period. Ocassional thin high clouds will continue...with scattered to
occasionally broken cumulus tomorrow. Tonight some areas of ifr to
even lifr fog possible between 10z-14z...especially over eastern
sections of the forecast area. Light south to southeast surface winds
expected through tomorrow. 12/DS
&&
.PREV DISCUSSION... /issued 352 PM CDT Tue Oct 18 2016/
NEAR TERM /Now Through Wednesday/...An upper level ridge of high
pressure remains the dominant feature across much of the Gulf Coast
region this afternoon, while a surface ridge of high pressure
continues to extend from the Western Atlantic through the
Southeastern U.S. Large scale subsidence and deep layer dry air is
generally keeping the region rain-free this afternoon, with the
exception of a couple of very isolated small and brief showers near
the immediate coast. Visible satellite imagery otherwise shows a
decent cumulus field across the region this afternoon and surface
observations continue to indicate above normal temperatures with
readings in the mid 80s near the coast and in the upper 80s to around
90 inland.
The upper level ridge of high pressure will continue to build
eastward over the Central Gulf Coast region tonight and eventually
over the Southeastern U.S. Wednesday. Though a very isolated shower
cannot be entirely ruled out mainly over far western portions of the
forecast area late tonight and Wednesday, deep layer subsidence and
low precipitable water values will preclude mentionable rain chances
in the forecast through Wednesday. Forecast soundings indicate a very
shallow moist airmass in place across much of our area tonight, which
will be a favorable setup for fog formation late. High resolution
and probabilistic data, including the HRRR, RAP and SREF all
indicate the potential for patchy to areas of fog to develop late
tonight and early Wednesday morning, particularly over interior
portions of the region. Fog could at least become locally dense, and
later shifts will need to monitor trends for a potential Dense Fog
Advisory. We added fog mention to the weather grids for a few hours
late tonight into early Wednesday morning. Otherwise, an unseasonably
warm and humid airmass will remain in place across our region through
Wednesday. Lows tonight are forecast to range from the lower to mid
60s inland, and in the upper 60s to around 70 near the immediate
coast and beaches. Highs Wednesday will once again range from the mid
80s near the beaches to the upper 80s to around 90 inland. /21
SHORT TERM /Wednesday night Through Friday night/...Wednesday
through Thursday night, shortwave energy just east of the US Rockies
digs south over the Plains, then swings east, pushing a weakening
front across the fa Thursday night. At this point, guidance is
advertising the wind shift portion of the front staring across the
fa around 00z Fri and just southeast of the marine portion of the fa
by around 09z. Any chance for severe weather will be very low, with
instability being lost as the fa heads into the night time hours.
Enough instability may be present in the early to mid afternoon
(1000-1500j/kg) for a strong to severe storm, mainly along and west
of the Alabama/Mississippi state line with a bit better low level
southerly flow. Wind shear will be generally on the weak side,
though, with 0-3km helicities at 20 m^2/s^2 or less during the late
afternoon close to the front. Also, any decent upper support remains
well north of the fa, over central and northern Alabama. All in all,
am not going to raise the severe weather with this fropa, just a
keep an eye on the weather over Mississippi.
For the numbers for Wednesday through Thursday night, with the
continued southerly flow and an upper high slowly slowly shifting
east over the Southeast, temps well above seasonal, ranging from mid
60s inland to around 70 along the coast. Do not see shra lasting
much into the evening hours, if at all. With moisture levels on the
high side, overnight fog development is again likely, with a few
localities dipping into the dense category closer to sunrise. Temps
Friday remain well above seasonal levels as the upper high brings
enough subsidence when combined with the southerly flow to being
temps well above seasonal. Highs in the low to mid 80s expected with
a chance of shra/tsra. Thursday night, as the front crosses the fa,
temps drop closer to seasonal levels as the front and its rain moves
southeast of the fa and skies clear.
Friday through Friday night, cooler air overspreads the fa, bringing
temps around to a bit below seasonal to the area. /16
LONG TERM /Saturday Through Tuesday/...As the Thursday/Thursday
night weather making upper trough moves off the Eastern Seaboard
through the weekend, An upper ridge builds east over the Gulf of
Mexico and associated coastal areas. A ridge shifts east over the
Plains, pushing a surface high that settles over the Southeast
behind the front eastward a bit, but the moisture returning onshore
flow remains well west of the fa. Subsidence from the upper level
high pressure building/shifting over the fa will bring temps rising
back to well above seasonal levels, mainly during the day, but with
a dry airmass remaining over the fa, overnight lows around to a bit
below seasonal remain. /16
MARINE...Surface high pressure will continue to ridge across the
Western Atlantic and Southeast States through Wednesday night, before
weakening Thursday in advance of an approaching cold front. The front
is forecast to push across the marine area late Thursday evening into
Thursday night, and will be followed by building high pressure into
the Northern Gulf and Southeast States through the weekend. A
generally light to occasionally moderate southerly to southeasterly
flow this evening will gradually become southeasterly to easterly by
Wednesday. A moderate to strong offshore flow will spread across the
marine area Thursday night into Friday following frontal passage.
Wind speeds may reach advisory criteria Thursday night, potentially
lasting into Friday night over the offshore waters, and possibly some
of the bays and sounds. Winds should veer northeasterly to easterly
and slacken late Saturday night into Sunday as high pressure shifts
east and the gradient weakens. /21
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1051 PM CDT TUE OCT 18 2016
.UPDATE...
Issued at 1050 PM CDT Tue Oct 18 2016
Updated to include 06z aviation discussion below.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 341 PM CDT Tue Oct 18 2016
Most exciting thing happening during the short term is a weak cold
front currently up across central NODAK into northern MN will
work across the area tonight, exiting off to our southeast
Wednesday morning. Atmosphere is pretty dry in the wake of Mondays
front (which is now stretching from around St. Louis up into
western Quebec), so rainfall and even cloud cover will be lacking
with this front. However, a pocket of weak instability has
developed ahead of the front over central ND, with a few showers
noted on regional radar between Bismark and Fargo. RAP MUCAPE
forecast shows this pocket of instability weakening considerably
as it works toward MN, which means those showers in ND will be
quickly running out of steam as they cross into MN. As a result,
have kept the forecast dry, though a stray sprinkle or two can not
be ruled out up by Alexandria between 6pm and 10pm.
The passage of the cold front tonight will continue to chip away
at temperatures/dewpoints, with h85 temps dropping from around
+6C today to around +2C tomorrow. This will result in highs about
5 degrees colder than what we are seeing this afternoon. Did not
stray to far from SuperBlend temperatures tonight, with highs
tomorrow lowered slightly from SuperBlend values, closer to what
you get when mixing down from 900mb.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 341 PM CDT Tue Oct 18 2016
The Wednesday night through Tuesday forecast remains on track. Dry
weather is expected for nearly the entire period. Temperatures
on Thursday will be in the mid 40s to near 50, which is around 5
degrees below the seasonal average for mid-October. Temperatures
on Friday will rebound slightly, with above normal temperatures
expected Saturday through Tuesday.
Precipitation chances are near zero the entire period. A weak wave
will bring showers over the Missouri River Valley Wednesday
night, but these should stay south and west of the forecast period
so removed pops during this time frame. On Friday warm air
advection will bring a band of light rain across northern MN, but
not anticipating much if any rainfall in the Twin Cities forecast
area. Continued with a 15 to 20 percent chance, but nothing more.
Finally, the 18.12Z ECMWF has changed considerably from its 00Z
counterpart. It is much more amplified and slower with the precip
at the end of the period keeping Tuesday dry. The GFS is trending
this way as well. For now have a 30 to 50 percent chance of rain.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1050 PM CDT Tue Oct 18 2016
Solid VFR conditions expected through the next 24-30 hours with
only mid-to-high level SCT clouds expected from time to time. A
cold frontal passage is expected overnight through daybreak
Wednesday morning, resulting in winds going from light/variable
overnight to NW 5-10 kt on Wednesday.
KMSP...No significant weather impacts expected. Timing of frontal
passage looks to be in the 10z-14z timeframe Wednesday morning.
/OUTLOOK FOR KMSP/
Thu...VFR. Wind NW 5-10 kts.
Fri...VFR. Wind SE 5 kts.
Sat...VFR. Wind S 5 kts.
&&
.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&
$$
UPDATE...JPC
SHORT TERM...MPG
LONG TERM...JRB
AVIATION...JPC
Area Forecast Discussion
National Weather Service Marquette MI
807 PM EDT Tue Oct 18 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 349 PM EDT TUE OCT 18 2016
Water vapor imagery and RAP analysis show wsw flow extending from
the Great Basin to western Quebec. Pair of strong shortwaves that
brought the shra/tsra and heavy rainfall to parts of Upper Michigan
last night are over Quebec, powered ene by 120kt upper jet. Shallow
moisture behind these systems and the low sun angle at this time of
year allowed low clouds to persist over much of the area this
morning. Even this aftn, it`s been a slow process clearing the
clouds with only the sw portion of the area now seeing mostly sunny
skies. A few -shra have even developed recently in Delta and sw
Schoolcraft counties where some sunshine has resulted in a little
instability.
During the short term, broad shortwave trof moving across the
western CONUS will begin to sharpen up as it moves out over the
western Plains on Wed. Meanwhile, a separate trof over Manitoba will
shift over northern Ontario on Wed as well. As these changes occur
at the mid levels, very gradual caa will drop 850mb temps that are
currently 6-7C down to around 0C over the Keweenaw to 4C over the se
fcst area by 00z Thu. With western Lake Superior water temps roughly
down to around 10c, lake effect pcpn won`t be a concern during the
short term. Couple of weak shortwaves and an associated sfc trof may
generate a few -shra or sprinkles. Given the overall weak forcing
and lack of deep moisture will leave pcpn out of the fcst. However,
there are some -shra in ND this aftn, so it`s certainly not out of
the question that there could be some -shra/sprinkles late tonight
and Wed. Temps on Wed will still be above normal over the e half of
the fcst area with highs in the upper 50s/lwr 60s. Over the far w,
highs will be around 50F into the lwr 50s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 343 PM EDT TUE OCT 18 2016
Upper trough is forecast to deepen late this week from the middle
conus to the Great Lakes. Conditions will turn cooler across Upper
Michigan with daytime temperatures falling a little below normal in
the 40s Thu-Sat. Normal highs are upper 40s to lower 50s. Temps at
about 5kft or h85 should be around -4c to -6c. Those h85 temps with
Lk Superior water temps 8-13c will result in delta t/s 12-19c which
is sufficient for some lake effect precipitation. Best chance for
precip will be Thu night into Fri morning as deeper moisture arrives
and inversions rise up to 7-8kft. Additional support for precip will
be from at least weaker shortwave energy moving through and uptick
in low-level convergence as sfc trough works across Lk Superior and
northern Upper Michigan. Low-level flow looks more cyclonic than it
did 24 hr ago, so overall the setup will be favorable for light to
perhaps moderate lake effect. Location of strongest, persistent
convergence is subject to change but attm looks like would affect
north central Upper Michigan on Fri morning. Ptype in this area
should remain rain with close proximity to warmer Lk Superior waters
and as 1000-850mb thickness remain above 1300m and sfc temps stay
aoa 38-39F. Farther inland west, wbzero heights blo 1000agl and sfc
temps aob 35F would support some snow mixing in with the rain, but
attm the overall coverage and intensity of precip for these areas
looks minimal.
Mean trough then deepens further over Quebec and the northeast conus
through the weekend while nw flow aloft continues across the Great
Lakes. Still uncertainty on how weekend works out. Even though axis
of mean trough will be well to the east and heights will try to rise
some, there may be additional shortwaves digging across area serving
to keep at least weak troughing in place. Any upper level system
working through will be moisture starved though as deep moisture
will be wrapped up in strong low spinning over Quebec. Just slight
chance pops for the weekend into early next week with temps around
normal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 807 PM EDT TUE OCT 18 2016
With dry air moving into the region, expect VFR conditions through
the foreast period. There may be period of mid clouds and a few
sprinkles Wednesday as a weak cold front moves through. As the front
moves through winds will veer from w to nw.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 343 PM EDT TUE OCT 18 2016
Expect winds to remain 20-25 kts or less through the rest of the
week and into the weekend as a relatively weak pressure gradient
dominates.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
Area Forecast Discussion
National Weather Service Sioux Falls SD
424 AM CDT Wed Oct 19 2016
.SHORT TERM...(Today and Tonight)
Issued at 424 AM CDT Wed Oct 19 2016
Split flow regime will influence the weather today across the
forecast area. A short wave will move across Nebraska through the
day, most evident in the 700-500mb layer and shows up well with the
mid level QG forcing fields. But to the north, our area is largely
influenced by a subtle wave dropping southeastward on the southwest
periphery of an upper low in southeast Canada. This northern stream
wave will bring an associated surface cold front southward with it,
evidenced by falling 925-850mb temperatures through the day. The
atmosphere is moisture starved below about 750mb in our extreme
southern zones, with the moisture even higher based as you approach
I 90. The frontogenetic forcing is fairly strong in the 750-700mb
layer, but remains to our south. Due to the proximity of the
southern stream wave, have some likely pops in our extreme southern
zones, from southern Gregory county to near Yankton for light
rainfall. Measurable pops decrease rapidly heading north and
eastward from that axis, although some sprinkles could fall out of
the mid deck of clouds as far north as I 90 during the middle of the
day. Another item to watch at least this morning is the massive
stratus deck in ND and northern MN. Based near 925mb, the current
NAM and GFS do not have a very good handle on it, but the RAP does.
The RAP brings it down into our extreme northern zones this morning,
generally from northern Beadle county to near Marshall before it
mixes it out by midday. This should not have a major influence on
our highs as we will have abundant mid and high level clouds with
the two short waves anyway. Because of the cloud cover and cold air
advection, lowered highs a bit based on 925mb temperatures, ranging
from the mid 50s in our north, to lower 60s in Sioux City and Storm
Lake.
Tonight, the main feature to watch is another very weak mid level
wave moving down the northwest flow aloft, which primarily affects
our western zones. The wave should be enough to give mostly cloudy
conditions along and west of I 29, with a small chance for light
rain in our far west. Lowered a few lows in our extreme east from
Windom MN to Spencer IA below consensus temperatures, where sky
cover should be clearer coupled with light northerly winds.
.LONG TERM...(Thursday through Tuesday)
Issued at 424 AM CDT Wed Oct 19 2016
Main trough will continue to dig toward to mid and southern
Mississippi valley early Thursday, but a secondary bit of northern
stream energy falling into the Dakotas will keep a good deal of
clouds along with a low threat for light showers going across parts
of southeast South Dakota near and south of I-90 early in the day.
Cold advection will continue with greater focus into areas along and
east of I-29. Models, other than ECMWF or WRF-ARW, are not very
enthusiastic about stratus potential within zone of more northerly
flow. Historically, predictions of stratus fields generally far from
a strong point in the models. Have hedged in a greater degree of
cloud coverage in the afternoon over the initialization blend,
especially across southwest Minnesota and into northwest Iowa, but
would not be surprised in the least to get a far greater coverage of
stratus even westward from there.
Diurnal cycle and proximity of surface ridge should help to flush
out lingering clouds by early evening, and with light winds and
clear skies should get a few lows down toward the freezing point
across northwest Iowa. Building ridge aloft will start to increase
high- and a few mid-level clouds, and increasing southerly flow will
slow or halt the fall in temps later in the night.
Large scale upper ridge will continue to build across the area, with
likely enough influence from wave traversing ridge along the
international border to push a weak boundary across the area Friday
night. However, a rapid return to warm advective patterns Saturday
with a bit breezier south winds developing. Will certainly be above
normal tempwise, but perhaps by quite a bit as warmer air noses up
into southeast South Dakota ahead of next frontal boundary to our
west.
Models working to resolve some timing discrepancies from Saturday
onward, but generally that is the only significant difference with
the stronger upper ridging over the area until the axis shifts
eastward early next week. Increasing southerly flow at low levels
will bring greater moisture, along with threat for stratus
developing around Monday night or Tuesday. There will also come the
start of a precipitation threat by Tuesday with warm front lifting
into the area, but greater precipitation/thunder threat just beyond
the forecast period as jet energy pushes out across the plains and
cyclogenesis occurs over the plains. Temps will continue above
normal through the end of the forecast period, with an abundance of
60s for highs, and lows moderating from 30s to lower 40s, into the
mid 40s to around 50 by the time southerly flow Monday and Tuesday
night.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1031 PM CDT Tue Oct 18 2016
VFR conditions will prevail through the TAF period. Scattered
showers will develop across areas generally south of Interstate
90 on Wednesday, but ceilings and visibilities are expected to
remain in the VFR range.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...MJ
LONG TERM...Chapman
AVIATION...JM
Area Forecast Discussion
National Weather Service Goodland KS
221 AM MDT Wed Oct 19 2016
.SHORT TERM...(Today through Friday night)
Issued at 221 AM MDT Wed Oct 19 2016
Early morning WV imagery and RAP upper level analysis shows a
shortwave trough over Wyoming and Colorado, with a region of
subsidence/dry air moving northeast out of south central Colorado.
At the surface Lo pressure is in place with a surface trough axis
extending north across eastern Colorado. A cold front is over then
Northern plains, moving into northeast Wyoming and approaching
southern South Dakota.
The shortwave trough will move east and pass over our CWA today and
tonight. Region of subsidence may remain in place over our southern
CWA limiting chances there. Moisture profiles will be slow to
saturate, and dry lower levels may limit potential for precip to
reach the surface. Limited instability and a slow increase in
moisture depth/moisture profiles could eventually allow light
showers to develop. Guidance is still showing an overlapping
weak precip signal in our north and northeast today and tonight,
with dry conditions elsewhere. By Thursday the trough will be
east, and subsidence ahead of building ridge in the west will
overspread our CWA. Very dry/stable air will then remain in place
through the rest of the week.
Regarding temperatures: The cold front in the northern plains
should pass over our CWA this morning and Canadian high pressure
will slide out of the Rockies towards the Central High Plains
tonight, then eastward through Thursday night. The air mass change
will support cooler temperatures Today and Thursday (upper
50s/lower 60s), before the flow aloft shifts and WAA brings above
normal temps back to the region Friday (mid 70s).
A frost (or freeze) is possible Thursday and Friday
mornings. As surface high pressure remains just west, we may see
enough of a gradient that winds around 10 kt could limit peak
radiational conditions to all but the far west tonight. There is
also a small chance that stratus develops along forward edge of
ridge ahead of low BL Tds, and this could hold overnight lows up.
On Thursday night/Friday morning radiational conditions may
better better, but the air mass will also begin to moderate
lowering confidence in lows. Ultimately a frost advisory may be
needed (06- 15Z) tonight/Thursday morning and Thursday
night/Friday morning for our west. There is enough uncertainty
that after coordination, the decision was made to hold off for
now.
.LONG TERM...(Saturday through Tuesday)
Issued at 153 AM MDT Wed Oct 19 2016
An upper ridge looks to be the dominating feature this weekend into
early next week. This leads to dry weather persisting for the large
majority of the extended period.
The ridge progresses onto the Plains over the weekend, with its axis
moving east of the region on Monday. Southwesterly flow then
develops aloft as a trough advances onto the Pacific coast on
Tuesday, bringing some moisture towards the High Plains. Will
continue to monitor how models resolve discrepancies with the trough
as next week draws near, but this appears to be our next shot at
precipitation.
Temperatures generally follow a slight cooling trend during this
time frame. Highs start out in the upper 70s to low 80s on
Saturday and end mainly in the low to mid 70s Tuesday. Lows stay
in the upper 30s to 40s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1000 PM MDT Tue Oct 18 2016
For KGLD and KMCK, vfr conditions expected through the period.
For KGLD winds begin the period from the southeast near 10kts
becoming variable around 5kts by 11z as a front begins to
approach the terminal. By 13z winds expected from the northwest in
the 5-10kt range. Winds increase with gusts of 20 to 30 mph from
the north in the 18z-22z timeframe. After 23z winds remain from
the north near 11kts. No precipitation expected. There is the
possibility of mvfr cigs in the 15z-19z timeframe. Right now
confidence too low to mention the threat.
For KMCK winds remain light for the entire period. Should see
winds from the east near 5kts gradually backing to the northeast
by 11z then north after 16z. No precipitation expected.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JBH
AVIATION...99
AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
350 AM CDT Wed Oct 19 2016
.SHORT TERM...
An upper level ridge has expanded across the entire Gulf coast to
the western Atlantic. It was centered overhead yesterday but has
shifted further east, much like the surface high pressure. Onshore
flow continues to increase moisture across the region. Dewpoints
have been slowly increasing, now in the lower to mid 70s. The latest
UA sounding shows that precip water is holding steady at around 1.6"
with quite a bit of dry air aloft. A warm layer cap around 15kft
continues to be in place and slightly more pronounced than previous
days. This cap along with dry air aloft will likely keep convective
development limited in spatial coverage as well as intensity. The
HRRR and medium range models all show some scattered showers between
New Orleans and Baton Rouge today. So have adjusted pops
accordingly.
Temperatures will continue to be unusually hot with high pressure in
place, so have kept forecast highs in the mid to upper 80s for the
next couple days. Blended guidance has been to cool, so trended the
max temps closer to the MAV.
.LONG TERM...
Models are still showing the next significant weather impact to be a
cold front marching through the area Thursday afternoon and through
the overnight period. Exact timing of the initial wind shift has
been bouncing around from run to run but attm it looks to begin late
in the afternoon on Thursday. With this slightly slower solution,
precip likely not starting till late morning in nwrn zones, then
spreading southeast in the afternoon. It appears that coverage will
steadily decrease as the front progresses across the CWA, which is
fairly typical this time of year. In fact, its possible that areas
from New Orleans and southward may not see any rainfall at all. A
significant drop in temperatures is expected Friday through the
weekend. A 15-20 degree drop in highs and lows are likely if model
solutions don`t change much between now and then. Friday through
Saturday night look to be the coldest with highs in the lower to mid
70s and nighttime lows dropping into the upper 40s to mid 50s.
Temperatures will begin moderating Sunday onward as upper trough
exits and ridge builds back in from the west. Next chance of rain
not till maybe latter part of next week.
Meffer
&&
.AVIATION...
VFR at most terminals through this taf cycle. As a cold front moves
closer to the area tonight and Thursday, fog should not be an issue
if cloud cover can remain overnight. Will keep ceilings in at around
BKN080 by later today and overnight.
&&
.MARINE...
A cold front will move rapidly through much of Louisiana and
Mississippi before slowing to a crawl between Baton Rouge to New
Orleans. The front then gets reinforced and moves rapidly through
the coastal waters Thursday evening. Strong thermal discontinuity
and tight pressure gradient will cause winds to abruptly increase
immediately behind the front a it moves through. Small craft
advisories will likely be necessary by Thursday at the earliest.
Winds may stay elevated through a portion of the weekend before
easing by the start of the new week.
&&
DECISION SUPPORT...
DSS code: Green.
Deployed: None.
Activation: None.
Activities: None.
Decision Support Services (DSS) Code Legend
Green = No weather impacts that require action.
Blue = Long-fused watch, warning, or advisory in effect or
high visibility event.
Yellow = Heightened impacts with short-fused watch, warning
or advisory issuances; radar support.
Orange = High Impacts; Slight to Moderate risk severe; nearby
tropical events; HazMat or other large episodes.
Red = Full engagement for Moderate risk of severe and/or
direct tropical threats; Events of National Significance.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 88 68 84 57 / 20 10 50 10
BTR 88 70 87 59 / 20 10 40 10
ASD 89 67 86 59 / 10 0 20 20
MSY 88 70 87 64 / 10 10 20 20
GPT 86 68 83 61 / 10 10 10 20
PQL 88 64 85 60 / 10 10 10 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
400 AM EDT Wed Oct 19 2016
.SHORT TERM...(Today and tonight)
Issued at 357 AM EDT WED OCT 19 2016
00Z raobs/latest wv imagery and RAP analysis show some lo amplitude
upr troffing centered over Manitoba extending into the Upr Great
Lks. A shrtwv embedded in this flow/sfc cold fnt is moving toward Lk
Sup, and the accompanying weak dynamic support and mstr shown on the
00Z INL raob has resulted in a good deal of cld cover over nrn MN
moving into the nw cwa. But the relatively weak dynamic forcing/
fairly dry llvls has limited the accompanying pcpn to some isold
showers. Behind the cold fnt, 00Z h85 temps are as lo as -7C at The
Pas Ontario. There is a good deal of lo cld within the thermal trof
trailing the cold fnt.
Today...As the aprchg shrtwv/cold fnt cross Upr MI today, some of
the hi res models generate some lgt pcpn over the Keweenaw this
mrng with upslope w wind enhancing the llvl moistening. So wl add a
mention of some isold light showers in that area. Only some clds wl
accompany the fnt elsewhere. Following the fropa, h85 temps area fcst
to fall to arnd -2C over the w by 00Z Thu, not sufficiently cold for
lk effect pcpn with the wrn Lk Sup buoy reporting a water temp of 9C.
Although the sfc wnw flow wl turn more acyc, upstream sfc obs sug
some lo clds should dvlp/persist over at least the w with the upslope
flow behind the fropa even if the models seem to downplay the lo clds.
Downsloping of the wind should break up these clds over the central.
Max temps wl range fm the upr 40s over the w to the lo 60s over the
scntrl.
Tngt...As the upr trof deepens a bit into the Upr Lks, h85 temps are
progged to fall to -4C to -6C over the nrn tier of the cwa by 12Z
Thu in the nw llvl flow ahead of sfc hi pres moving toward MN. These
temps are sufficiently cold for some lk effect pcpn. Some negatives
for this pcpn are the larger scale acyc flow under fcst deep lyr
qvector dvgc/subsidence and inverted-v nature of the fcst llvl T/Td
profiles shown on the fcst sdngs blo moist lyr at subsidence invrn
base near h85. Since many of the hi res models show some isold
showers over mainly the e half with longer fetch acrs Lk Sup and
downwind of additional moistening off Lk Nipigon, opted to add some
lo chc pops for some showers in the favored nw wind locations e of
Munising. Sfc temps should be sufficiently warm for only rain in
this area given the warm lk temps, as hi as 13C at the Grand Marais
buoy.
.LONG TERM...(Thursday through Tuesday)
Issued at 323 AM EDT WED OCT 19 2016
Nam shows a 500 mb trough over the upper Great lakes 12z Thu that
digs into the ern U.S. Fri night. GFS and ECMWF show about the same
thing as well. 850 mb temperatures off the GFS and NAM over Lake
Superior drop to around -4C at 12z Thu and then fall to -4C to -6C
over Lake Superior Thu night and Fri. With lake temperatures from 9C
to 12C, this is still enough for lake effect pcpn and had to put in
some slight chance to low chance pops in to cover this into Fri
night. Overall, did not make too many changes to the going forecast
for temperatures or weather except to bump up pops a bit for lake
effect pcpn.
In the extended, GFS and ECMWF show a 500 mb ridge over the southern
plains 12z Sat with a deep 500 mb trough in the ern U.S. 850 mb
temperatures 12z Sat over Lake Superior are from -4C to -6C with
lake temperatures from 9C to 12C. This is still enough for lake
effect pcpn. A shortwave moves into the upper Great Lakes 12z Sun.
the 500 mb ridge builds into the northern plains 12z Mon and this
ridge builds into the upper Great Lakes on Tue. Temperatures will
remain near normal for this forecast period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 121 AM EDT WED OCT 19 2016
With dry air moving into the region, expect VFR conditions through
the foreast period. There may be period of mid clouds and a few
sprinkles Wednesday as a weak cold front moves through. Winds will
also veer from w to nw with the frontal passage.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 357 AM EDT WED OCT 19 2016
Expect winds to remain 20-25 kts or less through the rest of the
week and thru the weekend as a relatively weak pressure gradient
dominates.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...07
AVIATION...JLB
MARINE...KC
Area Forecast Discussion
National Weather Service Sioux Falls SD
626 AM CDT Wed Oct 19 2016
.SHORT TERM...(Today and Tonight)
Issued at 424 AM CDT Wed Oct 19 2016
Split flow regime will influence the weather today across the
forecast area. A short wave will move across Nebraska through the
day, most evident in the 700-500mb layer and shows up well with the
mid level QG forcing fields. But to the north, our area is largely
influenced by a subtle wave dropping southeastward on the southwest
periphery of an upper low in southeast Canada. This northern stream
wave will bring an associated surface cold front southward with it,
evidenced by falling 925-850mb temperatures through the day. The
atmosphere is moisture starved below about 750mb in our extreme
southern zones, with the moisture even higher based as you approach
I 90. The frontogenetic forcing is fairly strong in the 750-700mb
layer, but remains to our south. Due to the proximity of the
southern stream wave, have some likely pops in our extreme southern
zones, from southern Gregory county to near Yankton for light
rainfall. Measurable pops decrease rapidly heading north and
eastward from that axis, although some sprinkles could fall out of
the mid deck of clouds as far north as I 90 during the middle of the
day. Another item to watch at least this morning is the massive
stratus deck in ND and northern MN. Based near 925mb, the current
NAM and GFS do not have a very good handle on it, but the RAP does.
The RAP brings it down into our extreme northern zones this morning,
generally from northern Beadle county to near Marshall before it
mixes it out by midday. This should not have a major influence on
our highs as we will have abundant mid and high level clouds with
the two short waves anyway. Because of the cloud cover and cold air
advection, lowered highs a bit based on 925mb temperatures, ranging
from the mid 50s in our north, to lower 60s in Sioux City and Storm
Lake.
Tonight, the main feature to watch is another very weak mid level
wave moving down the northwest flow aloft, which primarily affects
our western zones. The wave should be enough to give mostly cloudy
conditions along and west of I 29, with a small chance for light
rain in our far west. Lowered a few lows in our extreme east from
Windom MN to Spencer IA below consensus temperatures, where sky
cover should be clearer coupled with light northerly winds.
.LONG TERM...(Thursday through Tuesday)
Issued at 424 AM CDT Wed Oct 19 2016
Main trough will continue to dig toward to mid and southern
Mississippi valley early Thursday, but a secondary bit of northern
stream energy falling into the Dakotas will keep a good deal of
clouds along with a low threat for light showers going across parts
of southeast South Dakota near and south of I-90 early in the day.
Cold advection will continue with greater focus into areas along and
east of I-29. Models, other than ECMWF or WRF-ARW, are not very
enthusiastic about stratus potential within zone of more northerly
flow. Historically, predictions of stratus fields generally far from
a strong point in the models. Have hedged in a greater degree of
cloud coverage in the afternoon over the initialization blend,
especially across southwest Minnesota and into northwest Iowa, but
would not be surprised in the least to get a far greater coverage of
stratus even westward from there.
Diurnal cycle and proximity of surface ridge should help to flush
out lingering clouds by early evening, and with light winds and
clear skies should get a few lows down toward the freezing point
across northwest Iowa. Building ridge aloft will start to increase
high- and a few mid-level clouds, and increasing southerly flow will
slow or halt the fall in temps later in the night.
Large scale upper ridge will continue to build across the area, with
likely enough influence from wave traversing ridge along the
international border to push a weak boundary across the area Friday
night. However, a rapid return to warm advective patterns Saturday
with a bit breezier south winds developing. Will certainly be above
normal tempwise, but perhaps by quite a bit as warmer air noses up
into southeast South Dakota ahead of next frontal boundary to our
west.
Models working to resolve some timing discrepancies from Saturday
onward, but generally that is the only significant difference with
the stronger upper ridging over the area until the axis shifts
eastward early next week. Increasing southerly flow at low levels
will bring greater moisture, along with threat for stratus
developing around Monday night or Tuesday. There will also come the
start of a precipitation threat by Tuesday with warm front lifting
into the area, but greater precipitation/thunder threat just beyond
the forecast period as jet energy pushes out across the plains and
cyclogenesis occurs over the plains. Temps will continue above
normal through the end of the forecast period, with an abundance of
60s for highs, and lows moderating from 30s to lower 40s, into the
mid 40s to around 50 by the time southerly flow Monday and Tuesday
night.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 623 AM CDT Wed Oct 19 2016
Mid and high level clouds will be abundant today. But despite
areas of light rainfall south of I 90 today, the low levels are
pretty dry, so conditions should be VFR. There is one thing to
watch however for the morning hours. There is MVFR stratus to the
north of the forecast area, currently in northeast SD and North
Dakota. All indications are, that the stratus will remain north
and east of the TAF sites, possibly affecting the Brookings SD
and Marshall MN areas by mid morning, exiting midday. With a
northerly flow continuing today, it will need to be watched to see
if any of this stratus sneaks into KHON or KFSD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...MJ
LONG TERM...Chapman
AVIATION...MJ
Area Forecast Discussion
National Weather Service Goodland KS
521 AM MDT Wed Oct 19 2016
.SHORT TERM...(Today through Friday night)
Issued at 221 AM MDT Wed Oct 19 2016
Early morning WV imagery and RAP upper level analysis shows a
shortwave trough over Wyoming and Colorado, with a region of
subsidence/dry air moving northeast out of south central Colorado.
At the surface Lo pressure is in place with a surface trough axis
extending north across eastern Colorado. A cold front is over then
Northern plains, moving into northeast Wyoming and approaching
southern South Dakota.
The shortwave trough will move east and pass over our CWA today
and tonight. Region of subsidence may remain in place over our
southern CWA limiting chances there. Moisture profiles will be
slow to saturate, and dry lower levels may limit potential for
precip to reach the surface. Limited instability and a slow
increase in moisture depth/moisture profiles could eventually
allow light showers to develop. Guidance is still showing an
overlapping weak precip signal in our north and northeast today
and tonight, with dry conditions elsewhere. By Thursday the trough
will be east, and subsidence ahead of building ridge in the west
will overspread our CWA. Very dry/stable air will then remain in
place through the rest of the week.
Regarding temperatures: The cold front in the northern plains
should pass over our CWA this morning and Canadian high pressure
will slide out of the Rockies towards the Central High Plains
tonight, then eastward through Thursday night. The air mass change
will support cooler temperatures Today and Thursday (upper
50s/lower 60s), before the flow aloft shifts and WAA brings above
normal temps back to the region Friday (mid 70s).
A frost (or freeze) is possible Thursday and Friday
mornings. As surface high pressure remains just west, we may see
enough of a gradient that winds around 10 kt could limit peak
radiational conditions to all but the far west tonight. There is
also a small chance that stratus develops along forward edge of
ridge ahead of low BL Tds, and this could hold overnight lows up.
On Thursday night/Friday morning radiational conditions may
better better, but the air mass will also begin to moderate
lowering confidence in lows. Ultimately a frost advisory may be
needed (06- 15Z) tonight/Thursday morning and Thursday
night/Friday morning for our west. There is enough uncertainty
that after coordination, the decision was made to hold off for
now.
.LONG TERM...(Saturday through Tuesday)
Issued at 153 AM MDT Wed Oct 19 2016
An upper ridge looks to be the dominating feature this weekend
into early next week. This leads to dry weather persisting for
the large majority of the extended period.
The ridge progresses onto the Plains over the weekend, with its
axis moving east of the region on Monday. Southwesterly flow
then develops aloft as a trough advances onto the Pacific coast on
Tuesday, bringing some moisture towards the High Plains. Will
continue to monitor how models resolve discrepancies with the
trough as next week draws near, but this appears to be our next
shot at precipitation.
Temperatures generally follow a slight cooling trend during this
time frame. Highs start out in the upper 70s to low 80s on
Saturday and end mainly in the low to mid 70s Tuesday. Lows stay
in the upper 30s to 40s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 521 AM MDT Wed Oct 19 2016
VFR conditions should prevail through the TAF period, with
upstream trends and current short range guidance no longer
favoring MVFR cigs this morning. A few light showers or virga will
be possible, mainly over southwest Nebraska (KMCK) this afternoon
through late tonight. Confidence in coverage was too low to
include mention in TAF. Winds will shift to the northeast as a
front moves through the region and increase to 10-12kt (a few
gusts to 20 kt at KGLD). Winds then decrease tonight and
eventually back towards the northwest as high pressure builds west
to east.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JBH
AVIATION...DR
Area Forecast Discussion
National Weather Service Marquette MI
Issued by National Weather Service Gaylord MI
1109 AM EDT Wed Oct 19 2016
.UPDATE...
Issued at 1109 AM EDT WED OCT 19 2016
12z composite analysis shows a surface cold front crossing western
Lake Superior/western Upper Michigan...trailing southwest back
into southern Wisconsin. Decent low level cold advection behind
this front pulling low clouds into far western Upper and the
Keweenaw Peninsula...12z INL sounding shows a moist layer trapped
between 900-825mb with gravity waves evident in the cloud deck
beneath a sharp inversion. Upper Peninsula lies north of a 130kt
jet axis lifting northeast out of Iowa/southern Wisconsin/northern
Lower Michigan...with general large scale subsidence across the
upper Great Lakes.
Front will continue to traverse the U.P. this afternoon with
winds shifting to the west/northwest in its wake. Biggest issue is
the upstream cloud cover...leading edge of this cloud deck should
continue to advance east this afternoon. Guidance suggests that a
back edge should develop over western Lake Superior and spreading
into western Upper Michigan later this afternoon. Not totally
enamored with this idea given current satellite trends...though
eventually should start to get into some more lake induced
cloudiness by this evening. But should be a decent afternoon
across much of southern/eastern Upper with temperatures well into
the 50s.
&&
.SHORT TERM...(Today and tonight)
Issued at 357 AM EDT WED OCT 19 2016
00Z raobs/latest wv imagery and RAP analysis show some lo amplitude
upr troffing centered over Manitoba extending into the Upr Great
Lks. A shrtwv embedded in this flow/sfc cold fnt is moving toward Lk
Sup, and the accompanying weak dynamic support and mstr shown on the
00Z INL raob has resulted in a good deal of cld cover over nrn MN
moving into the nw cwa. But the relatively weak dynamic forcing/
fairly dry llvls has limited the accompanying pcpn to some isold
showers. Behind the cold fnt, 00Z h85 temps are as lo as -7C at The
Pas Ontario. There is a good deal of lo cld within the thermal trof
trailing the cold fnt.
Today...As the aprchg shrtwv/cold fnt cross Upr MI today, some of
the hi res models generate some lgt pcpn over the Keweenaw this
mrng with upslope w wind enhancing the llvl moistening. So wl add a
mention of some isold light showers in that area. Only some clds wl
accompany the fnt elsewhere. Following the fropa, h85 temps area fcst
to fall to arnd -2C over the w by 00Z Thu, not sufficiently cold for
lk effect pcpn with the wrn Lk Sup buoy reporting a water temp of 9C.
Although the sfc wnw flow wl turn more acyc, upstream sfc obs sug
some lo clds should dvlp/persist over at least the w with the upslope
flow behind the fropa even if the models seem to downplay the lo clds.
Downsloping of the wind should break up these clds over the central.
Max temps wl range fm the upr 40s over the w to the lo 60s over the
scntrl.
Tngt...As the upr trof deepens a bit into the Upr Lks, h85 temps are
progged to fall to -4C to -6C over the nrn tier of the cwa by 12Z
Thu in the nw llvl flow ahead of sfc hi pres moving toward MN. These
temps are sufficiently cold for some lk effect pcpn. Some negatives
for this pcpn are the larger scale acyc flow under fcst deep lyr
qvector dvgc/subsidence and inverted-v nature of the fcst llvl T/Td
profiles shown on the fcst sdngs blo moist lyr at subsidence invrn
base near h85. Since many of the hi res models show some isold
showers over mainly the e half with longer fetch acrs Lk Sup and
downwind of additional moistening off Lk Nipigon, opted to add some
lo chc pops for some showers in the favored nw wind locations e of
Munising. Sfc temps should be sufficiently warm for only rain in
this area given the warm lk temps, as hi as 13C at the Grand Marais
buoy.
.LONG TERM...(Thursday through Tuesday)
Issued at 323 AM EDT WED OCT 19 2016
Nam shows a 500 mb trough over the upper Great lakes 12z Thu that
digs into the ern U.S. Fri night. GFS and ECMWF show about the same
thing as well. 850 mb temperatures off the GFS and NAM over Lake
Superior drop to around -4C at 12z Thu and then fall to -4C to -6C
over Lake Superior Thu night and Fri. With lake temperatures from 9C
to 12C, this is still enough for lake effect pcpn and had to put in
some slight chance to low chance pops in to cover this into Fri
night. Overall, did not make too many changes to the going forecast
for temperatures or weather except to bump up pops a bit for lake
effect pcpn.
In the extended, GFS and ECMWF show a 500 mb ridge over the southern
plains 12z Sat with a deep 500 mb trough in the ern U.S. 850 mb
temperatures 12z Sat over Lake Superior are from -4C to -6C with
lake temperatures from 9C to 12C. This is still enough for lake
effect pcpn. A shortwave moves into the upper Great Lakes 12z Sun.
the 500 mb ridge builds into the northern plains 12z Mon and this
ridge builds into the upper Great Lakes on Tue. Temperatures will
remain near normal for this forecast period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 723 AM EDT WED OCT 19 2016
An extensive area of lo clds/MVFR cigs upstream in MN wl impact IWD
and CMX for at least at time this mrng into the aftn with an
upslope wnw wind before some daytime heating/mixing causes these clds
to sct out. Daytime heating/mixing wl also allow for some gusty
winds today, mainly at the more exposed CMX site. With nocturnal
cooling tngt, expect more clds/MVFR cigs again under subsidence
invrn. Downslope nature of the wnw shifting nw flow at SAW should
result in predominant VFR conditions there.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 357 AM EDT WED OCT 19 2016
Expect winds to remain 20-25 kts or less through the rest of the
week and thru the weekend as a relatively weak pressure gradient
dominates.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...None.
Lake Superior... None.
Lake Michigan... None.
&&
$$
UPDATE...JPB
SHORT TERM...KC
LONG TERM...07
AVIATION...KC
MARINE...KC
Area Forecast Discussion
National Weather Service Pendleton OR
858 AM PDT WED OCT 19 2016
.UPDATE...Skies are mostly clear for much of the forecast area this
morning. Did add some patchy fog into the forecast through midday
for the higher mountain valleys in Oregon, including near Meacham,
Ukiah, Long creek, Seneca and John Day. Otherwise high clouds will
gradually increase from west to east over the region by this
afternoon...lowering and thickening toward evening. Only made minor
adjustments to the PoPs, QPF and WX for tonight...as the short term
forecast looks on track. A warm frontal boundary will move over the
CWA this evening bringing increasing moisture. The latest HRRR model
seemed too fast bringing rain showers into the Columbia Gorge prior
to 5 PM today...so for now the short term forecast was based largely
on a 12z NAM and GFS blend. Precipitation totals by daybreak
Thursday are expected to range from a few hundreths or less over the
Lower Columbia Basin and surrounding Foothills...with a quarter to
half inch possible along the East Slopes of the Washington Cascades.
On Thursday the frontal boundary remains nearly stationary over the
forecast area during the morning, then begins to slowly drop south
and east as a cool front in the afternoon. This will keep chances
for rain and showers in the forecast through the day for just about
the entire area. 77
&&
.PREV DISCUSSION... /issued 457 AM PDT WED OCT 19 2016/
SHORT TERM...Today through Friday...A brief ridge will build into
WA and OR today. A warm front will lift across the forecast area
tonight bringing back precipitation. The ridge will then flatten on
Thursday and allow a front to stall across the forecast area. The
front will slowly weaken over time. A few showers will linger Friday
along the frontal boundary. Temepratures will be slightly warmer
over the next three days with Thursday expected to be the warmest
day. Coonfield
LONG TERM...Friday night through Tuesday...An upper level trough
looks to linger off the west coast of the U.S. through this period.
This trough would keep a general southwesterly upper level flow
over the Pacific Northwest through Tuesday. A weak disturbance
within the southwest flow looks to move across the region Friday
night, then there may be a break on Saturday. For now will continue
to indicate some showers over our northeastern most zones Saturday,
though these may be done by mid morning. From Saturday night onward,
a series of disturbances look to swing across the region bringing
varying chances of showers. Snow levels will slowly lower Sunday
through Tuesday, reaching a range of 4500 to 5500 ft by Tuesday.
High temps look to run near to slightly below seasonal, while low
temps look to run near to slightly above seasonal. 90
AVIATION...12Z TAFs...VFR conditions are mainly expected during the
next 24 hours. A weak, transitory high pressure ridge will move east
across the region today. This ridge will be followed by the next
Pacific system tonight. Patchy MVFR clouds will continue near KDLS
early in this period. Otherwise expect fair conditions with
gradually increasing mid and high level clouds today into this
evening. Showers are expected to spread east of the Cascade crest
roughly after 20/00 UTC. Showers will be possible at KDLS and KYKM.
May see a few showers in the vicinity of KRDM, KPSC and KALW. Winds
will be generally 10 kts or less. 90
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 61 45 65 47 / 0 20 40 60
ALW 62 50 64 50 / 0 20 50 60
PSC 62 47 64 48 / 0 20 40 30
YKM 61 45 62 41 / 0 50 50 20
HRI 63 45 67 47 / 0 20 30 40
ELN 59 44 58 40 / 0 60 60 20
RDM 61 40 65 41 / 0 10 20 20
LGD 57 45 58 44 / 0 20 40 40
GCD 57 41 61 44 / 0 10 20 20
DLS 62 49 64 48 / 0 60 50 20
&&
.PDT Watches/Warnings/Advisories...
OR...None.
WA...None.
&&
$$
77/91/91
Area Forecast Discussion
National Weather Service Shreveport LA
1051 AM CDT Wed Oct 19 2016
.UPDATE...
Expand 18z pop in both time back to now 15z and also pm coverage.
&&
.DISCUSSION...
A weak disturbance over S TX can now be seen on the water vapor on
that sneaky SW flow. Generally, speeds aloft are lighter than
this time yesterday, but that is good for any rain makers that do
develop in that motion will be slower giving more needed rainfall.
The HRRR model is spot on and now a reflection of our expectation
with this mornings update to pop and weather over Deep E TX and
also the expansion in afternoon coverage now anticipated with peak
heating unfolding. Other forecast elements are in good shape. /24/
&&
.PREV DISCUSSION... /issued 808 AM CDT Wed Oct 19 2016/
AVIATION...
For the 19/12Z terminal forecast period, will start off with
IFR/MVFR flight categories and these will start to improve
to VFR in the late morning to mid day hours. VFR categories will
continue into the overnight hours until after 20/06z when a cold
front will be moving into parts of Southeast Oklahoma and
Southwest Arkansas with a chance of showers and thunderstorms.
IFR/MVFR ceilings will be moving North across East and Northeast
Texas and Northwest and North Central Louisiana with a chance of
showers and thunderstorms moving North. Showers and thunderstorms
will continue during the day Thursday as the surface boundary
moves Southeast. Surface winds will be South to Southwest
5-12 knots through the late afternoon and into the early evening.
Winds will be shifting to the West and Northwest with frontal
passage. /06/
PREV DISCUSSION... /issued 341 AM CDT Wed Oct 19 2016/
DISCUSSION...
WV imagery this morning shows upper trof digging esewd across the
Four Corners region, with the upper ridge centered over the nrn
Gulf Coast beginning to shift ewd in response. Cold front
associated with upper low over ern Canada currently draped across
srn MO/central OK will be pushed slowly swd today as the trof
moves into the Plains. This will trigger shwrs/tstms across SE OK
by this aftn, a few of which could be strong to severe. Very
little in the way of deep-layer shear will limit the longevity of
any severe storms as well as the potential for dmg wind gusts.
However, moderately steep lapse rates will make hail the most
likely threat with any severe storms. The front will finally get a
good swd kick as the trof digs further sewd tonight, and
convection will continue to accompany it. However, instability
during the overnight hours will likely be too meager to support a
severe threat. Models continue to indicate that much of the
overnight/morning tstms will be of the elevated, post-frontal
type, which will further limit any potential for severe weather.
Gusty nwly winds and falling temps in the wake of the front will
finally bring a more fall-like feeling to the region Thursday
afternoon/evening.
Sfc high will settle in over the region Friday as NW flow aloft
sets up in the wake of the trof, and below-normal temps will
continue through the weekend. However, temps will begin to warm
moving into next work week, as the sfc high moves ewd, sly flow
returns, and the upper ridge makes yet another comeback. /12/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 90 70 77 54 / 20 40 50 10
MLU 91 69 81 53 / 10 30 50 10
DEQ 89 64 75 48 / 20 60 20 0
TXK 89 67 74 51 / 20 50 30 10
ELD 88 67 74 50 / 20 40 50 10
TYR 89 67 76 52 / 10 50 30 0
GGG 88 68 75 52 / 20 50 50 10
LFK 91 70 79 54 / 20 30 50 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
24/06/12
Forecast discussion for routine afternoon forecast issuance
.SHORT TERM...Tonight and Thursday
Issued at 213 PM CDT Wed Oct 19 2016
The latest RAP analysis and satellite/radar imagery show a cold
front moving southeast from Red Wing to Rhinelander early this
afternoon. Temps are in the 60s ahead of the front, and fall back
into the 50s behind it. Some cu has developed along and behind the
boundary, but the widespread overcast conditions reside north of the
U.P. border and farther west into Minnesota. The rest of area is
seeing scattered mid and high clouds overhead, with a more
widespread batch over South Dakota that is struggling to move into
Wisconsin. With no precip expected along or behind the front, sky
and temp trends are the main forecast concerns.
Tonight...The cold front will be exiting eastern WI during the
evening. Little in the way of clouds associated with the front, but
scattered to broken mid and high clouds will continue to pass
overhead before departing overnight. Scattered lake clouds may also
move into far northern WI as 850mb temps fall to -5C over western
Lake Superior. Colder lows with a slight north wind into the low 30s
north to low 40s south.
Thursday...A large scale trough will be moving into the western
Great Lakes above a chilly airmass with brisk northwest winds. With
daytime heating and flow continuing off Lake Superior, should see
plenty of cloud cover develop over northern Wisconsin. Downsloping
should help keep eastern WI partly sunny. As a result, temps will
be cooler over the north, only into the low to mid 40s. Highs over
eastern WI should reach into the lower 50s.
.LONG TERM...Thursday Night Through Wednesday
Issued at 213 PM CDT Wed Oct 19 2016
Ridging will become established across the western Great Lakes
region by late this week, bringing a long period of dry weather
that is expected to last through the weekend and into early next
week. The main concern during this period will be temperatures, as
a cold airmass brings overnight lows into the upper 20s to middle
30s Thursday night and Friday night, with daytime highs on Friday
limited to the middle 40s to around 50 degrees. Once this cold
period is overcome, temperatures will slowly rebound during the
weekend and into early next week, with highs on Sunday reaching
the middle to upper 50s.
After the relatively dry, quiet period has passed a powerful low
pressure system will affect the western Great Lakes Tuesday and
next Wednesday. This system will bring the possibility of heavy
rain and some thunderstorms as modest instability advects north
Tuesday night and next Wednesday. There are still significant
model differences regarding the strength, timing and path of this
system so details are uncertain. However it appears more likely
that there will be a period of unsettled weather during this
portion of the extended.
&&
.AVIATION...for 18Z TAF Issuance
Issued at 1212 PM CDT Wed Oct 19 2016
Mainly vfr conditions will prevail across the taf sites
through the period. Mid and high clouds will push overhead across
much of the region through the evening before departing. Behind a
cold front, incoming colder air will likely bring in mvfr cigs over
northern WI late tonight into Thursday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kurimski
AVIATION.......MPC
Area Forecast Discussion
National Weather Service Lincoln IL
251 PM CDT WED OCT 19 2016
.SHORT TERM...(This evening through Thursday)
ISSUED AT 250 PM CDT Wed Oct 19 2016
19z/2pm surface analysis shows stationary frontal boundary extending
from southern Indiana southwestward into the Ozarks. Several
clusters of thunderstorms have developed along/north of the boundary
this afternoon, with the first cluster currently tracking across the
SE KILX CWA. Additional storms are noted further upstream around
St. Louis and across southwest Missouri. This convection will track
E/NE along the front and continue to impact mainly the southeast
half of the CWA tonight. Given a frontal position slightly further
north than previously forecast, have expanded higher PoPs further
northward as well. While minimal elevated instability exists across
all of central Illinois tonight, the highest values remain focused
closer to the baroclinic zone. As a result, have limited likely to
categorical PoPs and thunder mention to locations along and
southeast of a Springfield to Champaign line. Further northwest,
have only gone with chance PoPs for showers. Overnight lows will
range from the upper 40s far northwest around Galesburg to the upper
50s south of I-70.
As low pressure tracks along the frontal boundary into the Ohio
River Valley, precip chances will gradually decrease from west to
east across the region on Thursday. Will continue likely to
categorical PoPs along/east of I-57 through the morning, then will
decrease to just chance by afternoon before the showers taper off
and completely come to an end by evening. Total rainfall with this
system will be heaviest along the I-70 corridor where amounts of
1.50 to 1.75 will be common. Amounts will steadily drop off further
northwest, with just a couple hundredths of an inch expected from
the Peoria area northward. Skies will initially be overcast
Thursday morning, then will become mostly sunny along/west of I-55
by afternoon. Highs will generally be in the lower 60s, with cooler
upper 50s noted near the Indiana border where clouds/showers will
prevail throughout the day.
&&
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 250 PM CDT Wed Oct 19 2016
The upper level trough axis is forecast by all models to progress
east of the central/SE Illinois forecast area by Thursday evening
with subsidence and high pressure building into the area
subsequently. Northwesterly flow behind the departing trough will
bring in much cooler air...but also will keep a light breeze in
place through Thursday night. The lightest winds should be northwest
of the Illinois River nearest the approaching surface high pressure
center. As a result...patchy frost may develop by Friday morning
roughly northwest of a Havana to Bloomington line as temperatures
reach the mid 30s. Elsewhere...lows are expected to reach the upper
30s to lower 40s. Otherwise...slightly warmer temperatures and light
wind should prevent frost.
For Friday, clear skies, light winds, and cool temperatures are
expected as high pressure moves into the central IL area. Expect
highs in the mid to upper 50s, and lows Friday night near 40.
Fair weather will continue into early next week as high pressure
slowly slips into the southeastern U.S., upper level ridging builds
into the central U.S., and a warmer air mass begins to edge eastward
into the central IL area. Expect highs in the low to mid 60s
Saturday, and upper 60s to lower 70s Sunday through Tuesday...above
normal. Lows generally in the 40s to around 50...also slightly above
normal.
The next storm system to potentially impact the area looks to be
midweek according to a consensus of 12Z models. However...GFS and
ECMWF disagree on the amplitude of the responsible upper level wave
and therefore the speed of it`s progression. GFS ensembles also
break down consistency by the middle of next week implying low
predictability. Therefore...have slowly spread chance PoPs into
forecast through the day Wednesday and kept the higher Pops toward
areas west of the Illinois River.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1256 PM CDT Wed Oct 19 2016
Showers and a few thunderstorms will overspread parts of central
Illinois this afternoon/evening...as an area of low pressure
tracks along a frontal boundary stalled near the Ohio River. As
has been the case with the past few model runs, the latest data
suggests KPIA will be largely missed by the rain. As a result,
have maintained VFR conditions and only mentioned VCSH there.
Further southeast, showers will be more numerous and the chances
will be greater for MVFR conditions. Latest HRRR forecast hints at
periods of MVFR ceilings at both KDEC and KCMI this evening into
the overnight hours. Have therefore opted to include MVFR ceilings
down to 2500ft at both sites after 03/04z. While the greatest
instability will remain further south in closer proximity to the
boundary, enough elevated instability will be present to warrant
VCTS at all terminals except KPIA. As the low tracks further east
along the front, the area of showers will gradually pull further
eastward...resulting in an end to the precip from west to east
Thursday morning. Winds will initially be from the northeast at
around 10kt...then will back to the northwest by Thursday morning.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Onton
AVIATION...Barnes
Area Forecast Discussion
National Weather Service Mobile AL
316 PM CDT Wed Oct 19 2016
.NEAR TERM /Now Through Thursday/...An analysis of upper air features
today show a mid level pressure ridge extending from the Mid-Atlantic
to the northern Gulf. A broad trof axis is bringing lower heights
aloft across the central CONUS. At the surface, forecasters analyze a
surface ridge over the southeast while a quasi-stationary surface
front was draped from off the northeast US mainland, back across the
Ohio River Valley then crossing over into northern Texas.
In the near term, forecast remains governed by the synoptic scale
ridge over the southeast which will maintain a persistence type
forecast. For tonight, with dewpoints well into the 60`s, plenty of
boundary layer moisture coupled with light winds support the
development of overnight fog. Not overly confident we``ll see dense
fog, with advective pre-frontal clouds coming in from the northwest
to mitigate fog coverage but latest high resolution NAM and HRRR
guidance showing a strong signal of potentially widespread dense fog
formation (visibility <= 1/2mile) between midnight and sunrise. Dense
fog advisory may be required on next shift as observational trends
are assessed through the evening. Little change in overnight lows
with lower 60`s interior and 66 to 70 close to the coast.
Heading into the day Thursday, cold front is progged to begin
surging southeast, becoming aligned from across the Appalachians to
off the upper Texas coast by the close of the afternoon. The front,
looking to be knocking on the door-step of the northwest tier of
zones thru the afternoon, brings enough lift for the potential of a
slight chance of storms. Elsewhere, rain chances look very slim to
none. Daytime highs from 84 to 88 for Thursday will be the last day
we see these unseasonably warm temperatures for awhile. :) /10
.SHORT TERM /Thursday night Through Saturday night/...A major
shortwave trough now pushing east of the Rockies will push a cold
front across the region Thursday night. Lift along this boundary may
be able to develop some isolated to scattered thunderstorms in the
early evening hours otherwise only isolated light rainshowers are
expected overnight. Any precipitation will remain light. Cooler,
drier air will follow in the wake of the front along with at times
breezy northerly winds Friday. A big change in temperatures will
follow with afternoon high temperatures remaining in the 70s Friday
and Saturday...closer to normal for this time of year. Temperatures
Friday and Saturday night should range in the 50s along the coast
and 40s inland. /08
.LONG TERM /Sunday Through Wednesday/...Deep layer ridging expected
to persist over the region through at least Tuesday so have kept the
forecast dry. The surface high settles in over the southeastern
states so we should at least see a light onshore flow during the
afternoon. Daytime highs will climb into the mid 70s to near 80 on
Sunday then low to mid 80s through Wednesday. An uptick in morning
lows is also anticipated with lows along the coast generally in the
low to mid 50s near the coast and upper 40s to low 50s inland Tuesday
morning and upper 50s to mid 60s near the coast Wednesday morning and
low to mid 50s inland. Models indicate the potential of an upper
level shortwave trough moving through the flow Wednesday but lack of
run to run consistency and agreement between models so will leave
the forecast dry at this time. /08
&&
.MARINE...In the wake of a strong cold frontal passage Thursday
night into Friday, a moderate to strong offshore flow develops. Choppy
to rough conditions to develop on area bays and a building trend in
seas is expected over the open Alabama/northwest Florida Gulf
waters. The higher seas are forecast beyond 20 nautical miles out due
to the longer offshore fetch. Small craft advisories will likely be
required Thursday night into Friday. Offshore flow continues into
Saturday, but lessens in strength as axis of a large ridge of high
pressure builds east across the Mid-South. High pressure holds firm
across the southeast and the central Gulf coast Sunday and Monday.
/10
&&
.PRELIMINARY POINT TEMPS/POPS...
Mobile 64 86 59 77 / 0 10 30 10
Pensacola 67 85 63 78 / 0 10 20 10
Destin 70 84 65 78 / 0 10 20 10
Evergreen 61 88 57 76 / 0 10 20 10
Waynesboro 63 86 55 75 / 10 20 30 10
Camden 62 88 56 75 / 10 10 30 10
Crestview 61 87 61 78 / 0 10 20 10
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion
National Weather Service Nashville TN
244 PM CDT Wed Oct 19 2016
.DISCUSSION...
Focus for this forecast period remains the approaching upper
trough and associated cold front that will bring chances for
showers and thunderstorms Thursday through early Friday, along
with much cooler temperatures this weekend. Cold front is
currently stalled north of the Ohio River Valley, and will begin
to progress towards the southeast later today and tomorrow. The
front looks to start entering the mid state mid morning on
Thursday and be completely through the area by Thursday evening.
Before that, short term models such as the HRRR and WRF show
prefrontal showers impacting the area by 12Z Thursday, and the
latest run of the GFS also shows some precip signatures overnight
as well. Increased pops a bit to reflect this, but mainly looking
at the western 2/3 of the CWA with chance pops overnight for now.
On Thursday, the frontal forcing for showers and thunderstorms
should start in the northwest before noon, impact most of the mid
state during the afternoon, and cross the Plateau during the
evening. The SPC does have a marginal risk for severe
thunderstorms on Thursday, and the best shot for severe reports
will be during the afternoon when frontal forcing and peak heating
will combine to possibly help stronger convection develop. Most
models are on board with 1000-1500 J/kg of MUCAPE, and 40-50
knots of 0-6km shear. This will allow some prefrontal storms
and/or storms along the frontal boundary to possibly produce some
damaging wind gusts during the afternoon. Hail is a possibility
as well, but with the absence of steep lapse rates, not expecting
too much of a hail threat on Thursday. As the sun sets late in the
afternoon, instability drops off quickly, and this looks to end
the severe threat as the front continues southeastward. Left in
mention of thunderstorms on the Plateau before midnight, but after
that time, all trailing precip looks to just be shower activity.
Overnight Thursday into Friday precip chances will continue for
eastern areas, but also winds look to pick up a bit from Thursday
afternoon and into the day Friday. Surface pressure gradients
tighten up after FROPA, and mixing down 30 knot low level winds
should be pretty easy later on Thursday. Currently have sustained
winds as high as 15-20 mph in some locations with gusts over 25
mph at times. The strongest winds with current forecast thinking
will be Thursday evening, but winds will not let up much
overnight. Winds do not look strong enough for a wind advisory,
but look to be strong enough to mention between Thursday afternoon
and into the afternoon Friday.
Friday will have lingering chances for showers mainly along the
Plateau, but will clear out by the afternoon. High temperatures
will be much cooler, with highs only in the low to mid 60s for
most of the area and upper 50s on the Plateau. CAA behind the
front will bring in 4C-6C 850mb temps, so not expecting much
higher temps than the 60s on Friday and Saturday.
By Sunday, the upper trough slides further east and the upper
ridge tries to build in, and a warming trend will move in as
well. Sunday temps will hit the 70s again, and above average
temps will return to the mid state from Sunday through the end of
the forecast Wednesday. The GFS and ECMWF differ for Thursday`s
solution, but there may be chances for precip again next Wednesday
night into Thursday morning. Otherwise, after this event tomorrow
and early Friday, dry conditions will continue to dominate the
area.
&&
.AVIATION...
18Z TAF DISCUSSION.
Somewhat of a slow progression in overall wx pattern expected thru
20/18Z. Have reflected that in the terminals as diurnal driven
CU/AC along with streaming CI in swly upper level flow aloft,
should continue generally thru 20/00Z. Expect diurnal influences
to dissipate CU/AC fields generally after that, but as frontal
system approaches, a slow progression to VFR ceilings expected
20/05Z W to 20/11Z E with the potential of light shwrs maybe not
at TAF sites, but at least in the vicinity. Potential for MVFR
ceiling formation CKV/BNA possible by the 20/14Z-20/16Z time
frame, with categorical light shwrs reducing visibilities to MVFR
thresholds, and with the potential of enough instability in sfc
frontal vcnty CKV/BNA to led to tstm development. Sfc front might
move sw of CKV by 20/18Z, but timing uncertainties still remain,
so will continue mentioning of a swly low level wind flow
supporting generally sustained winds of 4 to 8 kts at all
terminals thru 20/18Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 67 78 51 63 42 / 30 80 60 10 0
Clarksville 64 72 46 61 39 / 30 70 40 0 0
Crossville 63 78 49 58 38 / 10 70 80 20 0
Columbia 66 79 49 63 40 / 30 80 60 0 0
Lawrenceburg 65 80 50 63 40 / 30 80 70 0 0
Waverly 65 72 48 61 41 / 30 70 40 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Barnwell
AVIATION........31
Area Forecast Discussion
National Weather Service Paducah KY
256 PM CDT Wed Oct 19 2016
.SHORT TERM...(Tonight through Friday night)
Issued at 256 PM CDT Wed Oct 19 2016
The primary surface boundary has lifted northwest of the entire
region this afternoon, which has allowed for plenty of sunshine
over the southern half of the area. Temperatures have climbed into
the upper 80s with dewpoints holding in the upper 60s to lower 70s
over most of the area. Besides breaking a few high temperature
records, this will result in more destabilization than previously
expected.
The bottom line is that a few severe thunderstorms will be
possible mainly over the northern half of our southeast Missouri
counties late this afternoon and into the early evening.
Marginally severe hail and a few damaging wind gusts will be
possible.
Precipitable water values will be near the 99th percentile
climatologically, so heavy rainfall will be a concern tonight and
Thursday. However, the storms should move at a decent clip, so
the primary heavy rainfall/flash flooding concern will be in areas
that experience training late this afternoon and tonight. This
will be most likely along the I-64 corridor in southern Illinois.
The front has pushed farther north than expected today, and
subsequently the 12Z models and later runs of the HRRR are slower
to bring the cold front back through the area. It will not likely
reach KCGI and KEVV until after 06Z tonight. With the primary
convective development tonight expected behind the front, much of
the area may end up dry through the evening. Will rapidly spread
the likely to categorical PoPs southeast through the area late
tonight. Thursday morning should be the wettest period for most
of the forecast area. The models are shifting the precipitation
east of the area by 00Z Friday. The remainder of the short term
forecast is dry.
Temperatures will be rather mild tonight with some cold advection
in the northwest late. However, there will be little recovery
Thursday, so it will feel drastically cooler with highs in the
60s, clouds and gusty northwest winds. Winds will stay up Thursday
night, so lows will be near normal, but the surface high will
settle overhead late Friday and Friday night. Friday will see
below normal temperatures despite full sun, and Friday night will
be see the coolest readings. Most of the area will be near 40,
with some locations dropping into the upper 30s. Dewpoints are
expected to be in the upper 30s throughout the area, so lows may
trend even lower with time. This could be the first potentially
frosty night of the fall.
.LONG TERM...(Saturday through Wednesday)
Issued at 256 PM CDT Wed Oct 19 2016
Above average confidence in the extended period. Recent operational
deterministic and ensemble mean runs are in agreement for the
general synoptic pattern over the weekend and through the beginning
of next week.
An H500 ridge moves in, bringing NW flow early Saturday behind the
deep, departing H500 trough. Daytime temperatures will be a bit
cooler than normal Saturday with highs in the mid to upper 60s. May
see 70 degrees in some locations, depending on how quickly southerly
sfc flow returns.
For Sunday through Tuesday, our forecast area remains in warm
southerly sfc flow and relatively dry northwest flow aloft. With a
clipper passing well to our northeast and high pressure set up in
the Southeast through this period, we will likely see a relatively
breezy Sunday. Overall this pattern means our forecast will stay
mild and dry through this period. Starting in the middle to the end
of next week, we start seeing hints of the next potential rain
chances, but uncertainty is still great as model solutions diverge
significantly regarding a deepening trough along the West Coast.
Temperatures bottom out Saturday morning with lows near 40 degrees.
Temperatures for Sunday through the middle of next week will be
slightly above normal, with highs in the lower to middle 70s, and
lows in the lower to middle 50s.
&&
.AVIATION...
Issued at 104 PM CDT Wed Oct 19 2016
The general trend in the guidance today is to hold off the arrival
of the cold front and any precipitation at the TAF sites. Will
therefore hold off on its arrival and any precipitation until the
overnight hours. Not sure how much TS there will be at this time,
so will maintain the VCTS treatment for 3-4 hours late tonight and
into the morning hours Thursday. Guidance is bullish for IFR
conditions behind the front, but confidence is not that great, so
have limited IFR to KEVV and KOWB in the morning hours. Gusty
northwest winds should develop at all sites through the morning.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...DRS
LONG TERM...BP2
AVIATION...DRS
Area Forecast Discussion
National Weather Service SAN ANGELO TX
331 PM CDT WED OCT 19 2016
.SHORT TERM...
(Tonight and Thursday)
It has been another warm day across West Central Texas with highs in
the mid and upper 80s, but that still makes it 5-10 degrees cooler
than the record readings from Tuesday for some locations. All eyes
on the cold front now moving through the Panhandle, where
temperatures are in the 60s as of 3 PM. Front should reach the
northern Big Country shortly before midnight, the Abilene and
Sweetwater areas shortly after midnight, and then race south to
along I-10 by sunrise. As we have mentioned in precious days,
forcing for convection looks to come mainly from the front itself,
which is something the models often have some difficulty handling.
The mesoscale HRRR and the TTU-WRF show scattered convection, mainly
across the eastern half of the area, and will use this as a first
guess for convection tonight. Already carrying chance PoPs and will
boost these slightly for the far eastern portions of the area around
Brownwood.
Convection may linger into Thursday morning across the southern half
of the area, but should be gone pretty quickly. Much cooler with
highs in the low to mid 70s. This is based on the idea that morning
stratus behind the front dissipates as drier air works its way into
the area. If this doesn`t happen, then highs may need to be adjusted
down a few degrees.
.LONG TERM...
(Thursday Night through Wednesday)
Post-frontal morning lows on Friday will be in the mid to upper
40s as upper high pressure and dry weather builds over the area
from the west. Highs on Friday will be in the mid 70s with
temperatures Saturday through Wednesday warming into the upper
70s to the lower 80s...normal highs for this time of year are in
the upper 70s. Morning lows will be in mid 50s on Monday with lows
in the lower 60s by Tuesday morning...normal lows being in the
lower 50s.
Dry weather will persist through mid-week. The upper level ridge
will broaden over the central states on Monday with the ridge
axis slowly moving over the eastern states by mid-week. Low to
mid-level moisture will begin building back over the forecast area
Sunday through mid-week. Precipitation chances should remain west
of the forecast area through the first half of next week...along
the dryline that will stretch from far West Texas northeast
across southeastern New Mexico and into the northern Panhandle.
15
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 57 72 47 73 / 40 10 0 0
San Angelo 59 74 46 75 / 30 20 0 0
Junction 61 72 46 74 / 30 20 0 0
Brownwood 61 73 46 73 / 40 20 0 0
Sweetwater 57 72 49 73 / 30 5 0 0
Ozona 60 73 46 74 / 20 20 0 0
&&
.SJT Watches/Warnings/Advisories...
None.
&&
$$