Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/24/16
Area Forecast Discussion
National Weather Service Albany NY
932 PM EST Wed Nov 23 2016
.SYNOPSIS...
A weak low pressure system will slowly track eastward
through the Great Lakes region overnight. This low pressure system
will move through the area Thanksgiving Day through Friday, bringing
mainly light snow and rain to the region. Cool and unsettled
conditions will linger into the holiday weekend.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 932 PM EST...Low pressure is approaching from the western
Great Lakes Region...along with its associated warm front from the
OH Valley. High clouds have increased this evening...and the
clouds should continue to thicken and lower based on the upstream
observations and the IR satellite picture. The 00Z KALY sounding
exhibits a very dry low level air mass with the cloud deck around
20 kft AGL /cirrus/. PWAT is 0.25 inches with sfc dewpts around
the fcst area in the teens to lower 20s. It will take some time to
moisten the air mass. Upstream some light sleet or a mixture of
light snow/sleet is occurring at KBUF and KDSV in wester NY. Much
of the echoes further downstream over central NY is virga at this
time. Some very light rain is occurring at KAVP in northeast PA.
The only very light freezing rain report is at KBFD in the
northwest PA.
The onset of very light pcpn looks to be around 06Z/1 am west of
the Hudson River Valley...as the very light snow or sleet is
possible. The latest 00Z NAM and HIRES HRRR continues to show the
leading edge of the pcpn drying up from the Hudson River Valley
east prior to 12Z. We backed off the POPS until 12Z in these
areas. Any light snow mixed with a little sleet west of the Hudson
River Valley looks light prior to 12Z on the order of a tenth or
two. Temps have fallen off into the teens over the southern Dacks
with 20s across much of the region except some lower 30s in the
mid Hudson Valley/NW CT. Expect lows in the teens to 20s, and
temps to be steady overnight. Temps were retrended based on
observations, and a Top Down approach was used for ptypes into the
mid to late morning using the latest NAM data. Once again light
snow with a little sleet were the dominate ptypes with a
transition to rain by the late morning into the pm.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
The weather should remain dry through most of the overnight then
pops will gradually increase close to dawn Thanksgiving morning
as some modest isentropic lift/cyclonic vorticity advection
develops ahead of the system`s warm front. Thermal profiles from
forecast soundings continue to show snow as predominant ptype with
entire column below freezing, with a gradual warming of the
boundary layer by late morning into early afternoon, which will
allow for snow to change and mix with rain in most valley
locations. Snow will linger in the mountains through the day, with
accumulations ranging from a dusting to around half an inch for
most of the area. Snow accumulations of 1 to 3 inches is possible
across the higher terrain in the Western Adirondacks and Mohawk
Valley regions. Dendritic growth zone still looks fairly high
aloft around 15 kft, so snow to liquid ratios should not be large.
Temps will remain cool with the clouds/precip around with mainly
30s for highs, except south of Albany where some temps could sneak
into the lower 40s.
Low level moisture lingers Thursday night as upper level ridging
and drier air aloft moves in. This set up may result in spotty
light snow grains or freezing drizzle in some areas. Probability
for any accumulating freezing drizzle is low at this time, so will
not mention in the HWO. Temps will cool to near or slightly below
freezing across much of the area with cloudy skies persisting.
A stronger and more progressive short wave trough will be moving
eastward across the Great Lakes on Friday, bringing more light
snow and/or rain showers to the region. Best chances for
measurable precip will be for areas north of I-90. Thermal
profiles indicate mainly snow or a snow/rain mix for the higher
terrain and rain for the valleys. The precip could start out as
some wet snow or light freezing drizzle in the valleys if it
arrives earlier in the morning. The bulk of the precip should
occur during the afternoon and evening as cyclonic vorticity
advection increases ahead of the short wave trough. Temps should
be closer to normal with a southerly flow developing in the
boundary layer.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
This will be a period of near seasonable temperatures of highs
ranging from around 30 degrees in the mid 40s Saturday through
Monday. Then a warmup begins with highs Wednesday reaching into the
mid 40s to upper 50s range.
Broad low pressure moving through the forecast area will set off
showers of rain and snow through Saturday. Then brief high pressure
provides a period of dry weather...particularly from Sunday night
through Monday night.
Deep low pressure will head out of the northern plains to the Upper
Great Lakes and southern Ontario by Tuesday night. This system will
spread rain and possibly freezing rain across the forecast area...
but strong overrunning will change the precipitation to all rain
pretty quickly. Significant rainfall is possible...with a brief
mix back to snow possible across the northern third of the
forecast area before a pronounced warmup on Wednesday as a warm
front tries to push north into Pennsylvania and New Jersey
Wednesday night. Significant rainfall will still be quite
probable.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
High pressure continues to move slowly north and east of the
region tonight, as low pressure approaches from the Great Lakes
Region with its associated warm front. A light mix of mainly snow
and rain is expected during the morning and into the afternoon.
VFR conditions will continue until the early to mid-morning as
clouds thicken and lower ahead of the warm front and weak low
pressure system. The better warm advection and light pcpn mainly
in the form of snow initially based on the NAM and GFS thermal
profiles will be btwn 09Z-14Z. The CIGS/VSBYS will lower into the
MVFR range at KGFL/KALB/KPSF. The better forcing for light snowfall
will be toward KGFL...and the pcpn should taper towards 17Z. KPOU
may stay VFR prior to 21Z. As the weak wave gets closer...and the
boundary layer continues to warm a batch of showers or light rain
ahead of the wave will likely impact KPOU/KALB/KPSF between 21Z-
00Z/FRI. Widespread MVFR conditions are expected at this time.
There may be lapses briefly to IFR levels. KGFL may see the better
chance of some light rain after 00Z/FRI.
The winds will be light and variable in direction at 5 kts or
less or calm tonight. Light east to southeast winds around 5 kts
are expected late tomorrow morning into the afternoon.
Outlook...
Thursday Night: Moderate Operational Impact. Chance of RA...SN...DZ.
Friday: Moderate Operational Impact. Chance of DZ.
Friday Night: Moderate Operational Impact. Likely RA.
Saturday: Moderate Operational Impact. Chance of SHRA.
Saturday Night: Moderate Operational Impact. Chance of SHRA...SHSN.
Sunday: Low Operational Impact. Slight Chance of SHRA.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
High pressure will depart the area tonight as a weak low pressure
system slowly tracks eastward through the Great Lakes region. This
low pressure system will move through the area Thanksgiving Day
through Friday, bringing mainly light snow and rain to the region.
Cool and unsettled conditions will linger into the holiday
weekend.
&&
.HYDROLOGY...
The next chance of precipitation arrives late tonight into
Thanksgiving Day, with snow, rain and possibly a light wintry mix
in some spots. The precipitation is expected to be light and will
have no impact on rivers and streams. Continued chances for light
snow/rain continue into the holiday weekend, with very little
change in river/stream levels expected.
A few inches to over a foot of snow depth has built up across
many higher terrain locations from this past weekend into early
this week. Only gradual melting is expected, as temperatures will
continue to be below freezing each of the next several nights,
with daytime highs mainly in the 30s.
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...JVM/Wasula
NEAR TERM...Wasula
SHORT TERM...JVM
LONG TERM...ELH
AVIATION...Wasula
FIRE WEATHER...JVM
HYDROLOGY...11/JPV/JVM
AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
541 PM CST Wed Nov 23 2016
.SHORT TERM.../Tonight through Thursday/
Issued at 315 PM CST Wed Nov 23 2016
Satellite imagery and trends indicate that the large stratus shield
covering the region is not breaking up at all this afternoon, and
its back edge is only eroding very slowly over Nebraska. With
impending sunset it is likely that the erosion will stall and the
clouds will persist and thicken overnight. This is climatologically
favored and also depicted by several of the high-resolution models
such as the HRRR and RAP. Have increased cloud cover and bumped up
low temperatures a bit overnight as a result. There is some question
as to whether fog will develop late tonight, especially in the
northeast where dewpoint depressions and ceilings will be lower, but
given the light but organized winds and relative lack of radiational
cooling, have held off on a mention for now.
On Thanksgiving Day a surface ridge will cross Iowa bringing calm or
variable winds and likely helping the clouds to persist for the most
part. Late in the day the next storm system will approach from the
west and spread light precipitation into our far west/northwest
counties late in the afternoon. Forecast temperatures and soundings
indicate light rain initially, changing over to light snow in the
northwest by around sunset. Any impacts from this system will likely
come on Thanksgiving night as discussed in the long term section
below.
.LONG TERM.../Thursday night through Wednesday/
Issued at 315 PM CST Wed Nov 23 2016
Will see relatively strong QG forcing across central and northern
Iowa on Thursday night as shortwave crosses the state. Isentropic
lift is also decent across northern Iowa where pressure deficits
fall quickly during the evening. Anticipate precipitation to
spread across the northern third/half of Iowa during the evening
as max forcing crosses the state. May initially be a cold rain in
many locations but should quickly transition to snow as sounding
falls to freezing or below in the low levels. The precipitation
will linger across the northeast for a few hours after midnight
but precipitation should end rapidly in most areas during the
early morning hours on Friday. Accumulating snowfall is expected
along and north of Highway 20 with an inch or two north of state
Highway 3.
There is not much in the way of cold air on the backside of this
small system and in fact, warm advection will quickly resume by
Friday afternoon. This will persist into Saturday as upper ridging
builds across the central United States. Next system approaches on
Sunday with strong moisture advection into the state by Sunday
afternoon. Showers are expected to push into Iowa by Sunday
afternoon and persist into midday Monday as a strong system winds
up across the northern Midwest. Conditions will be quite windy
during this time with surface low central pressure dropping to
around 980mb in western Minnesota. After the system passes, strong
cold advection is expected by later Monday into the middle of next
week with colder temperatures but not much in the way of
precipitation as the airmass will be dry.
&&
.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 540 PM CST Wed Nov 23 2016
CIGS to remain low through the period, with MVFR expected to drop
to IFR/LIFR overnight. Should see some rising CIGS to MVFR again
during the day Thursday. Winds to remain out of the NW tonight,
before beginning to switch back to the SE toward the end of the
forecast period. Any precipitation looks to hold off until just
beyond the current forecast period Thursday evening into early
Friday.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Lee
LONG TERM...Cogil
AVIATION...Beerends
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
529 PM CST Wed Nov 23 2016
.Discussion...
Issued at 339 PM CST WED NOV 23 2016
The upper level pattern through the weekend is highly progressive
with warm air advection resulting in above average temperatures.
The sharp shortwave trough which brought scattered convection to the
region last night and an extensive stratus deck in its wake has
moved into the OH Valley. While visible satellite imagery has shown
a slow but steady eastward shift of the clearing line over KS am
expecting that to slow to a crawl once the sun goes down. Will hold
onto the stratus for most of tonight with the only clearing
occurring over the far southwestern counties. The clearing should
accelerate on Thursday as the surface high retreats to the east and
upper level ridging shifts east through the plains.
The next shortwave trough is moving east into the Northern and
Central Rockies with some lightning noted with the system. A weak
surface low will form over the Central High Plains tomorrow morning
in response to the approaching shortwave and track east. However,
the best lift/rain chances will pass to the north of the CWA so will
maintain the dry forecast. THe bulk of the cold air advection will
occur Thursday night and with systems moving so quickly there is
little time for any cold air to take up residence.
Water vapor imagery shows the next system which the medium range
models bring into the region by Sunday is currently pushing towards
the Pacific Northwest. GFS and ECMWF solutions have been similar for
the past few runs and generate a rather robust h8 southerly jet
across KS/MO on Sunday. Favorable downward mixing suggests the model
blend is too low with the winds so have significantly raised them.
Degree of instability is questionable for thunderstorms as moisture
from the Gulf of Mexico will be lacking. But believe dynamics and
isentropic ascent will be sufficient to generate scattered showers.
Cold air advection looks moderately strong once this system exits
the region on Monday. Think the model blend may be underestimating
the degree of cooling and won`t be surprised if later forecasts
come in colder.
&&
.Aviation...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 529 PM CST WED NOV 23 2016
MVFR cigs prevailing over the region this evening and latest model
trends suggest little hope for improvement during the overnight
hours. In fact, latest RAP and HRRR forecast soundings, along with RH
time sections reveal deteriorating conditions after the 06z time
frame. As a result...have elected to offer an IFR mention at all
sites with the exception of MKC...which will be further evaluated for
the 06z issuance. After we get through tonight...VFR conditions to
return areawide after 14z as high pressure builds into the area.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Discussion...MJ
Aviation...32
Area Forecast Discussion
National Weather Service Hastings NE
952 PM CST Wed Nov 23 2016
.UPDATE...
Issued at 910 PM CST Wed Nov 23 2016
Updated the forecast for tonight into Thanksgiving morning to hit
fog wording a little harder as the clearing stratus line has
stalled, and may possibly retrograde to the west soon. Therefore,
as the HRRR indicates, I hit the fog a little harder with some
patchy dense fog wording for a swath across the majority of our
CWA.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 209 PM CST Wed Nov 23 2016
The story of today has been an expansive area of stratus
encompassing a good portions of the plains states in between a
surface ridge axis building south from the Dakotas and a surface
trough axis across Missouri and Arkansas. The low clouds have held
temps in the 30s and 40s this afternoon while to the west in good
insolation, temperatures have reached the 50s. The stratus will
gradually erode west to east this evening into the first part of the
night. Have concerns for the potential for fog development on the
edge of the low clouds and a couple of short term models suggest the
fog may be dense. Have included patchy fog for our entire area
tonight and later shifts will need to monitor conditions for
stronger fog wording, depending on how things develop.
During the day on Thanksgiving, another band of low clouds are again
expected to develop ahead of an approaching cold frontal boundary.
The cold front moves through during the afternoon with winds
increasing from the northwest behind the boundary. Pressure rises
average 3 to 6 mb behind the front and wind gusts near 30 mph are
expected, with the strongest winds occurring across our western
zones.
Sprinkles or a brief rain shower is possible along the northern
fringes of our cwa in proximity of the shortwave trough translating
southeast from South Dakota into eastern Nebraska and Iowa. Just not
looking for much in the way of accumulation with this light
precipitation. Daytime temperatures for Thanksgiving are looking
fairly seasonal in the 40 to 50 degree range for much of Nebraska
and this will be dependent upon cloud cover again, with some
warmer temps in the low/mid 50s forecast for north central Kansas.
.LONG TERM...(Thursday night through Wednesday)
Issued at 209 PM CST Wed Nov 23 2016
The winds decrease Thursday night as surface high pressure builds
south along the high plains behind the departing cold front.
Temperatures Thursday night will be cold again, averaging in the
20s in the drier airmass (cold for black Friday shoppers).
For the end of the week into the first part of the weekend, the
airmass moderates with rising heights and ridging across the
interior CONUS. Conditions will remain dry with temperatures rising
above normal into the 50s to near 60 degrees for highs.
An upper trough moves inland over the weekend with flow
transitioning southwest Sunday ahead of the approaching system.
Extended models are in decent agreement that the upper low will
lift out onto the plains Sunday afternoon, tracking northeast into
South Dakota. Rain showers are possible Sunday in the warm air
advection/warm sector, then currently have small chances for snow
showers in the cold sector/back side of the system Sunday night.
Even though there is some snow in the forecast, chances look
minimal at this time for wintry precipitation for our area based
on the current northern track of the system.
A dry, cooler, troughy pattern settles in through middle of next
week with temperatures turning colder and more seasonal for this
time of year.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday evening)
Issued at 559 PM CST Wed Nov 23 2016
Toughest issue will be sky cover and how much and fast stratus
backs to the west, which will affect fog potential as well. Gave
my best guess as models are not handling this well.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
UPDATE...Heinlein
SHORT TERM...Fay
LONG TERM...Fay
AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Lincoln IL
904 PM CST Wed Nov 23 2016
.UPDATE...
Issued at 903 PM CST Wed Nov 23 2016
The cold front continues to make steady progress toward Indiana,
already reaching I-57 as of 9 pm. The only precip still being
detected on radar is patchy drizzle east of I-55. The apparent
coverage of precip based on radar has been steadily decreasing
over the last couple of hours. No additional measurable precip is
expected the rest of the evening, so we reduced PoPs to below
slight chance and went with patchy drizzle and fog for the eastern
counties through 06z. The HRRR and RAP have been consistent in
showing fog and drizzle progressing east into Indiana by 06z,
which matched what we already had going in the forecast for after
midnight.
Forecast soundings continue to advertise enough moisture in the
low levels to keep mostly cloudy to cloudy conditions the rest of
tonight and most of tomorrow. Therefore, we increased cloud cover
tomorrow across the board. Did not adjust high temps down tomorrow
to due less potential for sunshine, but update later tonight could
address that trend. Updated forecast info is already available.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 229 PM CST Wed Nov 23 2016
Surface low has moved to just northwest of Jacksonville as of 2 pm,
with a trailing cold front through the St. Louis metro into south
central Missouri. Steadier rains have continued much of the day
across the eastern CWA, but has been significantly diminishing west
of I-57 as of late. High-resolution models have been consistent in
shifting this area east of the Indiana border by 6 pm, and have
limited PoP`s to the 30% vicinity this evening ahead of the front
itself.
Areas further west have only seen some drizzle the last few hours as
visibilities have started to drop with the lighter winds. Have gone
with areas of fog in the grids for this afternoon and evening,
timing the decrease from west to east as the front passes and winds
increase, although gridded guidance has been focusing on the areas
from about Bloomington-Lawrenceville eastward as potentially being
the lowest visibility.
While the rain and fog move out by midnight, clouds will be much
slower to erode, as the subsidence inversion hangs tight. The NAM
model actually never really breaks out of the clouds the next couple
days per forecast soundings, while the GFS is more optimistic and at
least gets some peeks of sun by Thursday afternoon. Leaned more in
that direction for sky grids for Thursday, trying to make them
partly sunny. However, we are at that time of year where the sun
angle does little to help erode the low clouds, and currently the
cloud deck extends all the way back into central parts of Kansas and
Nebraska. WRF simulated satellite imagery doesn`t really show any
improvement in that regard as well. So, a more cloudy scenario would
not be a great surprise at this point.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 229 PM CST Wed Nov 23 2016
A fast moving shortwave trough remains progged to reach the upper
Midwest Friday morning...however precipitation with this feature
should remain north of the central IL forecast area. After the
feature progresses to the east over the weekend...an upper-level
high pressure ridge will build over the central U.S. bringing fair
weather through early in the weekend and a warming trend lasting
into early next week. Highs Friday should range from the mid to
upper 40s most areas to a few lower 50s from around Jacksonville to
Lawrenceville. After warming slowly through the weekend...highs
expected to range from the low to mid 50s across the area Sunday and
mid and upper 50s Monday. Lows mainly upper 20s and lower 30s
through the weekend...but up to lower 40s Monday.
An active weather pattern looks to set up for late Sunday into early
next week. Initially a deep closed low will lift into the upper
Midwest late Sunday into Monday dragging a warm front northward
across Illinois and setting up a strong warm advection pattern with
a moist southerly flow into Illinois. Precipitable water values look
to rise as high as 1.25 inches east of I-57 according to the 12Z GFS.
This will result in potential for steady moderate to heavy rain
until another low tracks northeastward into the area Tuesday. Cooler
and drier weather should return for the middle of next week as the
system moves off to the east. Potential rainfall amounts late Sunday
to early Tuesday in the 1.5 to 2.5 inch range look to target areas
east of I-55 in the latest forecast model runs...although
considerable model differences remain to indicate continued forecast
uncertainty in timing and track of the system. Afternoon forecast
package will carry likely PoPs for the warm frontal passage Sunday
night....and likely to categorical from the Illinois River eastward
for at least a period Monday afternoon into Tuesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 546 PM CST Wed Nov 23 2016
IFR/LIFR conditions will continue for a few hours early this TAF
period until the cold front pushes east of I-57. The cold front
has passed Peoria at 23z and will pass SPI by 0030z, eventually
reaching CMI around 04z. Prior to FROPA, drizzle and IFR/LIFR
clouds and fog will prevail. The rain shield has already pushed
east of I-57, so the terminal sites should mainly see trace
amounts of drizzle this evening. As the front arrives at each
terminal site, winds will diminish for a few hours, and with the
extensive moisture in place, will likely bring ceilings down to a
few hundred feet for a time. Have kept the dense fog limited to
BMI for now, but can not rule out a brief period of dense fog
at the other terminals east of PIA. Following the front, visibility
will improve with the stronger northwest winds, but ceilings will
be slower to respond. MVFR conditions should prevail late tonight
into Thursday morning, with some improvement in ceilings coming
from the southwest. The GFS advertises clearing Thursday
afternoon, while the NAM remains pessimistic with overcast
conditions through the end of this TAF period. There most likely
will be a few breaks in the ceilings Thursday afternoon toward SPI
and possibly PIA, but confidence in complete clearing to just
cirrus per the GFS is low.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...Geelhart
LONG TERM...Onton
AVIATION...Shimon
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1040 PM EST Wed Nov 23 2016
.UPDATE...
Issued at 1040 PM EST WED NOV 23 2016
Showers have devolved to scattered at best out there. HRRR
suggests a bit more activity during the late night hours, but for
the most part not much more rain is expected. Have adjusted PoPs
and Wx with this in mind and also tweaked the T/Td grids per the
current obs and trends. These grids have been sent to the NDFD
and web servers with an updated ZFP on its way mainly to remove
evening wording.
UPDATE Issued at 730 PM EST WED NOV 23 2016
23z sfc analysis shows a low pressure system rolling through the
Great Lakes with a cold front working into the Ohio Valley. The
front is pushing a band of mainly light rain into eastern
Kentucky. This much welcomed moisture will come up short for the
vast majority of the area, though, with general amounts of 0.15
inches or less expected. Temperatures vary across the area from
the mid and upper 50s ahead of the rain through the eastern
Cumberland Valley to the upper 40s to the northwest and some of
the deeper valleys to the east. The arrival of the light rain and
somewhat lower clouds will help to mix out those colder spots
over the next few hours. Dewpoints vary from the low 20s in the
far east to the low and mid 40s west as the higher humidity air
starts to spread east. Have updated the grids mainly to fine tune
the PoPs per the latest HRRR and radar trends into the rest of
the night and also to capture the latest obs and trends for the
T/Td grids. These have been updated and sent to the NDFD and web
servers. An updated HWO will be issued shortly to remove earlier
Fire Wx concerns.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 303 PM EST WED NOV 23 2016
Lower layers of the atmosphere remain very dry across eastern
Kentucky. Despite this rain showers will eventually move into the
area tonight ahead of an advancing cold front. The initial rain
falling out of mid level clouds will result in virga and will
also go to moisten up the lower layers. As low layers moisten up
more widespread rain will occur tonight. As has been the case with
the past several weather systems, rain chances will be high, but
rain amounts will be low. Most areas will see less then 0.20 inch
of rain, with some spots in the far east likely seeing less than
0.10 inch.
In addition to the lower atmosphere moistening up, an extensive
area of low clouds near and behind the cold front will spread into
the area early Thursday as the front presses across eastern
Kentucky. Low clouds and possibly some very light rain or drizzle
will persist into Thursday night. While there will not be much
rain over the next 36 hours, minimum relative humidity on Thursday
will be much higher than this afternoon, which will be helpful
with the ongoing wildfires. Temperatures will be only slightly
cooler behind the front on Thursday and Thursday night, remaining
above normal.
.LONG TERM...(Friday through Wednesday)
Issued at 228 PM EST WED NOV 23 2016
Considerable low level moisture will remain trapped beneath a
subsidence inversion Friday into Friday night. This will likely
mean another cloudy day on Friday with patchy drizzle before
clouds scatter out late Friday night into the day on Saturday. The
rest of the weekend looks decent with fair to partly cloudy skies
and highs warming from the chilly mid 40s to low 50s on Saturday
well into the 50s on Sunday.
As we begin the new work week, a deep trough will be carved out
over the Rockies with ridging over the eastern CONUS. This trough
will slowly migrate eastward through Wednesday sponsoring the
development of at least a couple of surface low pressure systems
which will track northeastward out of the Plains and into the
Great Lakes and/or Ohio Valley. This will result in an increasing
chance for rain beginning on Monday. However, from the looks of
the 12z models, much of our area stays downsloped Monday through
Tuesday afternoon and the blended guidance depicted this well with
highest PoPs over our northwest counties and lowest over southeast
Kentucky. I brought PoPs to a peak late Tuesday into Tuesday
evening when a cold front should pass through bringing a very
beneficial widespread wetting rainfall. As previous forecaster
noted, this will be a fairly dynamic system but instability is
lacking. I kept the thunderstorm mention in the Lake Cumberland
region but did not expand that northeastward yet due to that lack
of instability in the models.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 710 PM EST WED NOV 23 2016
High to mid level clouds continue to increase across the area in
advance of an approaching cold front. The air at the lower levels
remains very dry and as showers move into the area tonight we
expect ceilings to initially remain VFR, with little restriction
to visibility from the showers. As the cold front works its way
deeper into the area Thursday morning ceilings are forecast to
lower to MVFR and then IFR. MVFR to IFR ceilings are the expected
to persist into Thursday night. Winds will continue to be
generally light from the south to southwest through the forecast
period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...SBH
LONG TERM...ABE
AVIATION...SBH/GREIF
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
550 PM CST Wed Nov 23 2016
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...
00Z issuance...VFR conditions through this evening followed by MVFR
cigs and visibilities later tonight and early thu morning followed
by vfr cigs through 25.00. Lower cloud bases and visibilities mostly
ahead and along a weakening frontal boundary approaching from the
northwest. Winds will be southeast to south at 5 to 8 kt through
early this evening shifting southwest diminishing to 3 to 5 kts late
this evening and overnight then shifting south to southwest at 5 to
8 knots during the day on thu. 32/ee
&&
.PREV DISCUSSION... /issued 413 PM CST Wed Nov 23 2016/
NEAR TERM /Now Through Thursday/...Upper air map analysis shows a
sharp trof axis moving eastward around 25 knots across the
Mississippi River Valley. Within the trof axis, a surface front was
also positioned in the same areas mentioned above. A north to south
zone of precipitable water values (above the mean) extends from the
Upper Mid-West to the western Gulf. Within this zone, precipitable
water values from 1.1 to 1.4 inches, moving into the Lower
Mississippi River Valley, lies between 130 to 160% of normal.
Satellite trends indicate that clouds will be on the increase and
thicken in the near term as the frontal zone approaches from the
west. Although there is moisture available, a rapid movement of the
better dynamics across the local area and the high level energy
dampening a bit, frontal ascent weakens through Thursday suggesting
showers will be lowering to isolated coverages at best in the near
term. This is already being observed in radar with returns moving
eastward across southern Mississippi and southeast Louisiana. These
trends also noted in high resolution HRRR and 4KM NAM output.
Precipitation amounts look light, mostly less than 5 hundredths of an
inch. There is also a signal in the high resolution NAM12 and the
SREF of showing increased probabilities of developing late night fog.
Visibility could be reduced to less than a mile at times. Overnight
lows in the mid 50s interior to lower 60s coast. Daytime highs on
Thanksgiving Day mostly in the mid ranges of the 70s. /10
SHORT TERM /Thursday night Through Saturday night/...An upper level
ridge of high pressure will gradually shift eastward over the
southeastern U.S. and western Atlantic Ocean Thursday night into
Friday as a weak shortwave trough translates toward the Ohio and
Tennessee River Valley region. An associated weak cold front will
push southeastward into our forecast area during the day Friday.
Moisture and lift ahead of this boundary will be very limited, but
there may be just enough available to aid in the development of a few
isolated light rain showers early Friday morning. Lows Thursday night
should range from the upper 40s to mid 50s over most interior areas,
with upper 50s to lower 60s expected near the immediate coast. Highs
Friday should warm into the 70s area wide.
Surface high pressure will build from the Southern Plains to the
Mississippi and Tennessee Valley region Friday night into Saturday,
then across the southeastern states Saturday night. No precipitation
is expected during this time frame as a deeply dry airmass settles
into the region. Clearing skies and cooler temperatures are expected
Friday night through Saturday night. Lows Friday night should range
from the lower to mid 40s inland to the lower to mid 50s coast. Highs
Saturday should range from the mid 60s to around 70. Lows Saturday
night trend a little cooler in the mid 30s to around 40 over the
interior to the mid 40s to around 50 near the immediate coast and
beaches. /21
LONG TERM /Sunday Through Wednesday/...The operational 12Z runs of
the GFS and ECMWF have come into fairly decent agreement in their
solutions with the evolution of the upper air pattern late this
weekend into early next week. Dry weather is expected to continue
across the forecast area Sunday as shortwave ridging aloft builds
from the western Gulf of Mexico to the Great Lakes. Upper ridging
is then forecast to shift eastward over the southeastern U.S. and
into the western Atlantic Ocean early next week as a broad longwave
trough deepens over much of the central CONUS Monday and Tuesday.
Surface high pressure will also subsequently shift from the eastern
U.S. into the western Atlantic early next week as surface low
pressure deepens and lifts northeastward across the northern Plains
and Great Lakes region. A surface cold front should subsequently
advance eastward toward the Mississippi Valley and Gulf Coast states
Monday into Tuesday.
The GFS and ECMWF both show an organized area of convection
advancing eastward toward our forecast area along and ahead of the
cold front sometime during the Tuesday-Tuesday night time frame as a
fairly potent shortwave trough advances eastward toward the
Mississippi and Tennessee Valley region. A low CAPE/high shear
environment will likely be in place over our area ahead of these
approaching features, with MLCAPE values between 250-500 J/KG per the
latest GFS, a developing 45-60 kt low level jet, and increasing
0-1km helicity values between 200-400 m2/s2. It therefore looks like
we will have to monitor for severe weather potential as convection
rolls into the area Tuesday. Otherwise, this system is looking like
it will bring the best chance of rain to our area in a good long
while. We have POPs trending upward to 20-30% with potential for
isolated to scattered warm advection showers Monday-Monday night,
with 50-60% POPs on tap for Tuesday. Rain chances currently appear to
decrease Tuesday night into Wednesday as the cold front moves east of
the region. /21
MARINE...A weakening front approaches the lower Mississippi River
Valley tonight and begins to slow across the central Gulf Coast
region on Thursday. The front makes passage by Friday morning. A
light onshore flow is forecast thru Thursday with winds shifting to
westerly then northerly behind the front Friday. High pressure builds
back into the Southeast US over the weekend, establishing a light
return flow off the Gulf by later in the day Sunday. A more potent
storm system moving across the plains on Monday, combined with high
pressure over the southeast results in a strengthening onshore flow
and building seas early next week. /10
CLIMATOLOGY...A lengthy period of abnormally dry conditions has
resulted in worsening drought conditions over the central Gulf coast.
Since September 27th, Mobile Regional Airport went through a bone-dry
spell of 42 consecutive days with no measurable rain and 41 days at
Pensacola before it finally rained again on November 8th. As it
stands to this date since September 27th, 56 days at Evergreen
straight, without measurable rain. Current annual rainfall deficits
stand at between 6 and 9 inches below normal. Drought has worsened
with severe to extreme drought conditions being experienced over the
local area. A more potent storm system impacting the area early next
week brings the most promising rain potential seen in quite some
time, but this system looks to be progressing eastward rapidly
enough as to do very little in placing a significant dent in the
drought. Stay tuned. /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 Dodge City KS
301 AM CST Thu Nov 24 2016
.SHORT TERM...(Today and tonight)
Issued at 254 AM CST Thu Nov 24 2016
We will need to watch the areas around Hays early this morning for
the potential of fog or stratus development, as the latest fog
channel imagery has been indicating this across Rooks county. The
HRRR fields however suggest that will not occur at this time. Going
foreword, a vigourous shortwave will drive a pacific surface cold
front into the High Plains region later this morning. The short wave
vort lobe will be moving across the area just behind the front,
adding to subsidence and helping create strong northwest winds
sustained to 30 mph and higher gusts. Surface winds weaken rapidly
with the loss of insolation. Not alot of variance in the model
lows tonight, however MOS products are generally cooler in the
teens across the higher elevation far western counties.
.LONG TERM...(Friday through Wednesday)
Issued at 254 AM CST Thu Nov 24 2016
The large scale pattern will remain progressive in the medium range.
Between the ECMWF and GFS there appears to be a general agreement on
a large trough developing in the west, and a closed low most likely
to move into the Northern Plains around the end of the weekend.
This won`t rule out our area for seeing clouds and even a
possibility for precipitation, however the main forcing mechanisms
near the warm front would be too far north in the upper midwest
with these model runs. As the low develops to the north, Sunday
looks to be a particularly windy day with a strong surface
pressure gradient and strong subsidence aloft. The region could
remain in cyclonic flow aloft easily through mid week, supporting
generally cold temperatures (cooler than climo highs).
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1256 AM CST Thu Nov 24 2016
VFR conditions are expected through the entire TAF period. Outside
of that, the main impact for aviation will be wind shear early
this morning, then gusty surface winds in the afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 59 27 58 31 / 0 0 0 0
GCK 57 23 58 27 / 0 0 0 0
EHA 58 26 58 30 / 0 0 0 0
LBL 60 24 58 29 / 0 0 0 0
HYS 56 28 58 30 / 0 0 0 0
P28 62 32 59 32 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Russell
Area Forecast Discussion
National Weather Service Hastings NE
1215 AM CST Thu Nov 24 2016
.UPDATE...
Issued at 910 PM CST Wed Nov 23 2016
Updated the forecast for tonight into Thanksgiving morning to hit
fog wording a little harder as the clearing stratus line has
stalled, and may possibly retrograde to the west soon. Therefore,
as the HRRR indicates, I hit the fog a little harder with some
patchy dense fog wording for a swath across the majority of our
CWA.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 209 PM CST Wed Nov 23 2016
The story of today has been an expansive area of stratus
encompassing a good portions of the plains states in between a
surface ridge axis building south from the Dakotas and a surface
trough axis across Missouri and Arkansas. The low clouds have held
temps in the 30s and 40s this afternoon while to the west in good
insolation, temperatures have reached the 50s. The stratus will
gradually erode west to east this evening into the first part of the
night. Have concerns for the potential for fog development on the
edge of the low clouds and a couple of short term models suggest the
fog may be dense. Have included patchy fog for our entire area
tonight and later shifts will need to monitor conditions for
stronger fog wording, depending on how things develop.
During the day on Thanksgiving, another band of low clouds are again
expected to develop ahead of an approaching cold frontal boundary.
The cold front moves through during the afternoon with winds
increasing from the northwest behind the boundary. Pressure rises
average 3 to 6 mb behind the front and wind gusts near 30 mph are
expected, with the strongest winds occurring across our western
zones.
Sprinkles or a brief rain shower is possible along the northern
fringes of our cwa in proximity of the shortwave trough translating
southeast from South Dakota into eastern Nebraska and Iowa. Just not
looking for much in the way of accumulation with this light
precipitation. Daytime temperatures for Thanksgiving are looking
fairly seasonal in the 40 to 50 degree range for much of Nebraska
and this will be dependent upon cloud cover again, with some
warmer temps in the low/mid 50s forecast for north central Kansas.
.LONG TERM...(Thursday night through Wednesday)
Issued at 209 PM CST Wed Nov 23 2016
The winds decrease Thursday night as surface high pressure builds
south along the high plains behind the departing cold front.
Temperatures Thursday night will be cold again, averaging in the
20s in the drier airmass (cold for black Friday shoppers).
For the end of the week into the first part of the weekend, the
airmass moderates with rising heights and ridging across the
interior CONUS. Conditions will remain dry with temperatures rising
above normal into the 50s to near 60 degrees for highs.
An upper trough moves inland over the weekend with flow
transitioning southwest Sunday ahead of the approaching system.
Extended models are in decent agreement that the upper low will
lift out onto the plains Sunday afternoon, tracking northeast into
South Dakota. Rain showers are possible Sunday in the warm air
advection/warm sector, then currently have small chances for snow
showers in the cold sector/back side of the system Sunday night.
Even though there is some snow in the forecast, chances look
minimal at this time for wintry precipitation for our area based
on the current northern track of the system.
A dry, cooler, troughy pattern settles in through middle of next
week with temperatures turning colder and more seasonal for this
time of year.
&&
.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Thursday night)
Issued at 1215 AM CST Thu Nov 24 2016
If anything, this continues to look like a more challenging
complex and largely sub-VFR period with at least the first half of
the period largely dominated by MVFR/IFR (perhaps even some LIFR?)
ceiling and the potential for at least a 3-6 hour stretch of
MVFR/IFR (possibly worse?) visibility centered especially during
the 09z-15z time frame as fog develops. The ultimate question is:
How dense and persistent might fog be, as there are varying
solutions in the latest models/guidance? Essentially, this latest
issuance strikes a "middle ground" between the more optimistic
previous forecast and the more pessimistic solution especially
advertised by NAM/MET guidance, which suggests that at least MVFR
ceiling could stick around through the entire period.
In addition to the considerable ceiling/visibility challenges, at
least one model (NAM) is more robust than others in developing
light rain/drizzle especially during the 16-00z time frame.
Probably cannot completely rule out a few wet snowflakes either,
but for now will simply introduce -DZ as precip type as better
chances for light snow should focus slightly north of the
terminals.
Last but not least, as usual confidence is a bit higher in wind
trends, but even then there are some slight timing differences in
the passage of a fairly well-defined cold front this afternoon. In
general though, most of these first 12 hours will see a prevalent
southeast breeze at-or-below 12kt, followed by a brief period of
variable direction before a stronger/steadier northwest breeze
arrives by mid-late afternoon behind the front. This northwest
wind should be a bit stronger overall at KEAR than KGRI, with gust
potential to 20+KT. By sunset and after, sustained speeds will
gradually subside below 10kt.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
UPDATE...Heinlein
SHORT TERM...Fay
LONG TERM...Fay
AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Gray ME
327 AM EST Thu Nov 24 2016
.SYNOPSIS...
High pressure will crest over the region early this morning before
sliding offshore. A weakening area of low pressure will approach from
the west later today and tonight before passing out to sea to our
south. Another area of weak low pressure will approach from the
west on Friday and will push into New England Friday night. A
trough of low pressure will remain over the region on Saturday
through Sunday. High pressure will build in from the west Sunday
night and Monday. High pressure will crest over the region Monday
night and will shift off to the east on Tuesday.
&&
.NEAR TERM /THROUGH TODAY/...
At 07z...a 1029 millibar surface ridge was draped across New
England. A 1012 millibar low was centered over the Great Lakes.
GOES imagery showed lingering low cloud across the Connecticut
valley northward through the international border area. Middle and
high clouds were advancing rapidly eastward from the Great Lakes
ahead of a shortwave impulse situated over the upper midwest and
Great Lakes. For today...the surface ridge will slide offshore
this morning. Thicker clouds will arrive from west to east later
this morning in weak warm air advection ahead of the shortwave
impulse. NWS doppler radar mosaic showed a band of mixed precipitation
associated with this disturbance over the eastern Great Lakes at
moment. This precipitation should arrive during the afternoon and
evening hours with HRRR and other short term numericals placing
the bulk of the QPF...albeit light over the northern half of New
Hampshire into adjacent western Maine. Forecast soundings are cold
enough for frozen precipitation today...with the exception of where
the precipitation is extremely light and boundary layer temperatures
are several degrees above freezing with some rain or a rain/wet
snow mix possible. High temperatures today will be limited to the
30s by clouds and precipitation. Snow accumulations later today
should be an inch or two for the higher terrain with less than an
inch elsewhere.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
For tonight...snow tapers to scattered flurries as the weakening
shortwave impulse exits the area to our east overnight. With loss
of ice crystals we may also see some patchy drizzle and freezing
drizzle overnight depending on surface temperatures. On
Friday...we have a quiet start as we are initially between disturbances
with clouds and scattered flurries along with some patchy drizzle
or freezing drizzle. By afternoon...the next weak disturbance will
be approaching from the Great Lakes with the next batch of warm
air advection precipitation arriving. High temperatures will range
from 30s in the mountains to near 40 elsewhere. Any light accumulating
snows should be limited to the higher terrain...while we`ll see a
rain/snow mix elsewhere.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Low pressure will develop/strengthen near Nantucket Island Friday
night and move northeastward on Saturday as potent short wave
trough approaches from the west. As this occurs, at least light
precipitation should develop across the CWA. At this time, the
thermal profile across much of the CWA supports rainfall, with a
mix and/or snow across the far interior. As secondary mid level
low pressure develops further just to the east of the Maine coast
on Saturday, colder air will filter in from the west and perhaps
change the rain over to snow even on the coastal plain Saturday
evening. At this time it appears as though the best forcing for
ascent will be found to the northeast of our CWA at this time and
this should preclude a major snow event in our CWA. However, it is
worth noting that there is still a good amount of model spread in
short wave trough strength and speed, and this still could have an
effect on mesoscale features at this juncture. Therefore, we still
cannot rule out the occurrence of a brief band accumulating snow
moving across portions of the region between Saturday and Sunday
morning.
Low pressure will move away from the region on Sunday with weak
high pressure building in on Monday. The fair weather will be
short-lived however as there is strong model and ensemble
agreement that that weather will quickly become active again
Tue through Thurs. At this time, low pressure is expected to bring
mainly rainfall then.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Short Term /Through Friday/...Areas of MVFR ceilings for the
Connecticut valley...then conditions lowering to mvfr with lcl ifr
in snow and rain btw 16 and 22z. Widespread mvfr and areas of ifr
tonight in -shsn and areas of drizzle and fog...with patchy
freezing drizzle.
Long Term...MVFR to IFR conditions are expected Friday night
through Saturday night as low pressure develops off the Maine
coast. Improvement is foreseen on Sunday as low pressure moves
away from the region...with VFR conditions prevailing into
Monday.
&&
.MARINE...
Short Term /Through Friday/...Quiet on the waters with conditions
remaining below small craft as high pressure crosses the waters
today then weak low pressure passes well to the south of the
waters early Friday.
High pressure builds overhead
tonight...allowing winds and seas to continue to diminish. Winds
remain light thru Thu...with conditions expected to remain below
SCA thresholds.
Long Term...SCA conditions are expected Sat night through sun
night as low pressure departs.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
Schwibs/Ekster
Area Forecast Discussion
National Weather Service Lincoln IL
317 AM CST Thu Nov 24 2016
.SHORT TERM...(Today and tonight)
ISSUED AT 317 AM CST Thu Nov 24 2016
Showers associated with a passing cold front have come to an end
across central Illinois early this morning: however, cloud cover
continues to blanket the area. 09z/3am IR satellite imagery shows
low clouds from Illinois as far west as eastern Nebraska/Kansas.
With surface ridge axis building into the region today, very light
low-level flow will do little to push the clouds away. In addition,
a strengthening subsidence inversion will only act to keep the
clouds locked in place. As a result, have gone with a cloudy
forecast today with chilly highs in the lower to middle 40s.
A short-wave trough evident on latest water vapor imagery over
eastern Utah will track E/NE into the southern Great Lakes by Friday
morning. Any associated precip will remain well north of central
Illinois across Wisconsin and far northern Illinois late tonight.
Forecast soundings suggest low clouds will remain in place, so will
continue the cloudy conditions through tonight with lows dropping
into the middle 30s.
&&
.LONG TERM...(Friday through Wednesday)
ISSUED AT 317 AM CST Thu Nov 24 2016
A period of mild and dry weather will prevail through the weekend,
before the next significant storm system comes into the picture
early next week. A vigorous wave apparent on water vapor imagery
near the Aleutian Islands will pivot S/SE around a deep upper low
anchored off the coast of British Columbia. This feature is
expected to come onshore across southern California on Saturday,
creating pronounced upper ridging downstream across the central
CONUS. Rising upper heights will mean rising temps across central
Illinois, with highs climbing into the lower to middle 50s by
Sunday. As the wave tracks across the Southern Rockies, then turns
northeastward toward the Upper Midwest, it will eventually spread
showers into the area by late in the weekend. Models continue to
slow this process, with most solutions now suggesting a mostly dry
day on Sunday, followed by showers arriving Sunday night. Will hold
on to low chance PoPs west of I-55 for Sunday afternoon, but these
will likely be removed by later shifts if current trends continue.
Main rain event is still on track from Sunday night through Monday
night, as deep-layer southwesterly flow establishes itself from the
Southern Plains into the Ohio River Valley. After an initial push
of showers associated with the first short-wave Sunday night, a lull
in the precip is expected Monday morning before a more significant
wave arrives later in the day. Models are still differing on this
second feature, particularly where to place the heaviest rainfall
axis. As was seen with previous model runs, the latest GFS prefers
a more western solution across much of central Illinois...while the
ECMWF is further east across southeast Illinois into Indiana. In
addition, significant model differences arise concerning a potential
third wave Monday night into Tuesday. The GFS brings another round
of rain across the E/SE CWA during that time, while the ECMWF is
more progressive and does not show another wave at all. At this
time, will stick to the going forecast fairly closely...which
features the highest PoPs and heaviest rainfall east of the I-55
corridor through Tuesday morning. Storm total rainfall could be
significant, with the latest forecast suggesting 2-3 inches
along/south of I-70. This of course is subject to change pending
better model agreement.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1139 PM CST Wed Nov 23 2016
LIFR conditions will continue for a couple of hours early this
TAF period for BMI and CMI, with IFR at PIA. SPI and DEC have
improved to MVFR and should remain there for a majority of this
TAF period. The cold front has progressed into Indiana already,
and westerly winds have increased at all TAF sites, with some
gusts to 20kt. Drizzle has ended at all terminal sites, and CMI
is the only site with IFR fog still in place. HRRR and RAP both
continue to indicate that extensive low level moisture will
remain across central Illinois the rest of tonight and most of
tomorrow. That will mean cloudy skies with MVFR ceilings during
the day tomorrow. Tomorrow evening, some improvement in ceilings
is expected to arrive from the southwest. The GFS advertises
clearing Thursday afternoon, while the NAM remains pessimistic
with overcast conditions through the end of this TAF period. There
most likely will be a few breaks in the ceilings late Thursday
afternoon toward SPI and DEC, and possibly PIA, with VFR
conditions possible for several hours Thurs evening. Confidence is
low that clearing will be as strong as the GFS is indicating as
early as Thursday early afternoon, but not quite as pessimistic
as the NAM.
Winds will diminish tomorrow morning, with speeds in the 6-10kt
range from the W-NW. Winds will become light and variable around
sunset, due to the arrival of the surface ridge axis across
Illinois.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Shimon
Area Forecast Discussion
National Weather Service North Platte NE
334 AM CST Thu Nov 24 2016
.SHORT TERM...(Today and tonight)
Issued at 333 AM CST Thu Nov 24 2016
Today and Tonight...a weak short wave moving through ncntl Colo this
morning will collide with arctic drape across ncntl Neb producing
scattered rain showers across ncntl Neb. The HRRR...RAP and NAM are
in good agreement lifting a band of showers through Holt county this
afternoon. A pacific cold front moving through cntl WY will sweep
east into the Neb Panhandle this morning and scour out the arctic
air and clouds across ncntl Neb this afternoon.
A blend of bias corrected RAP and HRRR model temperatures produces
highs in the 40s. Bias corrected guidance produces lows in the teens
and 20s tonight under clear skies.
The dense freezing fog this morning is forming mainly on the wrn
fringe of the arctic drape. This hazard is short lived in most
locations but could last several hours this morning according to the
time lapsed HRRR model. Temperatures will gradually warm above
freezing this morning reducing the hazard. The freezing fog advisory
operates until 12z and will be reevaluated at that time for a
possible extension or down-grade to a dense fog advisory.
.LONG TERM...(Friday through Wednesday)
Issued at 333 AM CST Thu Nov 24 2016
Upper level ridging and surface high pressure remain over the region
through Sunday. This ridge will result in dry conditions across
central Nebraska through much of the weekend. In addition,
temperatures will have a brief warm-up this weekend. Highs Friday
start off in the low to mid 50s before rising up into the upper 50s
on Saturday. Cooler temperatures begin to filter into the region on
Sunday with highs only rising into the upper 40s across the north
and into the low 50s across the south.
The next weather system arrives on Sunday night bringing a potential
of some wintry precipitation to central Nebraska. Current model runs
show this system mostly missing the north central Nebraska forecast
area. Just a chance of some rain mainly across Holt and Boyd
counties in the afternoon Sunday. Precipitation will then switch
over to snow, however, the system will be north of the area by then.
Will keep just a slight chance of some snow across the
Nebraska/South Dakota border as moisture wraps around this system
on Sunday night.
The low pressure system moves north and east of the area by Monday
night allowing another weak high pressure system to build northward
into the central Plains for the middle of next week. Temperatures
remain cooler through mid-week with highs only rising into the mid
to upper 30s each day. Lows remain steady from Friday night through
Tuesday night in the mid 20s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1126 PM CST Wed Nov 23 2016
Low cloudiness will continue to push west overnight across western
and north central Nebraska. The leading edge of this stratus is
expected to make it as far west as a line from near KIML to 40
East of KCDR. Cigs below 1000 FT agl are likely east of this line
overnight into mid day on Thursday. For the KLBF terminal, expect
CIGS around 500 FT AGL through late morning Thursday. CIGS will
then remain MVFR through late afternoon Thursday before lifting
out mid evening Thursday. In addition to low cloudiness, fog is
possible overnight with VISBYS around 2 SM. For the KVTN terminal,
expect CIGS around 500 FT AGL overnight into Thursday morning.
There is a threat for light snow Thursday morning with VISBYS
temporarily dropping down to 2 to 5 SM. CIGS will continue to
improve into the afternoon hours with scattered high clouds
expected by Thursday evening.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Freezing Fog Advisory until 6 AM CST early this morning for
NEZ037-038-059-071.
&&
$$
SHORT TERM...CDC
LONG TERM...Kulik
AVIATION...Buttler
Area Forecast Discussion
National Weather Service Saint Louis MO
401 AM CST Thu Nov 24 2016
.SHORT TERM... (Through Late Tonight)
Issued at 313 AM CST Thu Nov 24 2016
A weak RIDGE aloft prevails over our region early this morning, with
a light northwest flow at the surface. A surface RIDGE axis extends
from eastern Nebraska into far western Missouri. An expansive area
of low cloudiness exists across much of the Midwest, with its
backedge just to the west of the surface RIDGE axis. This backedge
has not moved over the past several hours. Temperatures were in the
upper 30s to mid 40s across our region.
The 06/07z RAP runs as well as the updated 06z NAM seem to be
handling the low clouds the best and were used as primary guidance.
These models persist the low cloud field across our region into the
afternoon hours with some clearing occurring for some sections south
of Interstate 70 in central and southeast MO. With the low level
RIDGE axis sliding thru late this morning and early afternoon,
advection will be negligible in moving this cloud field and this
being late November, it is unlikely the sun will be able to
dissipate. A light southerly low level flow into central MO and
southeast MO during the afternoon look like the best opportunity for
limited clearing. Max temps will also be cool today for areas near
and north of I-70 where the clouds will persist, with conditional
climatology suggesting a mere 5 degree rise, and have strongly
preferred the MET MOS values in these areas with peak readings in
the 40s. Trended towards the MAV MOS in southern areas, with peak
readings in the low 50s.
Light winds becoming more northerly with time tonight will, if
anything, allow the low cloud field near and north of I-70 to drop
south again and recover lost ground. In addition, an upper level
disturbance will drop thru our region. Models generally show a
decently strong region of broadscale lift and some WAA that will
also bring in thicker ice-containing clouds. The system is rather
fast moving, however, and will work on a very dry column. The
column will be too warm for anything but liquid pcpn, but unless the
system can produce stronger lift than is currently being depicted,
it will be tough to get any pcpn going with this when it moves thru
tonight. Have continued the dry forecast. Went warm on min temps
tonight with lots of clouds persisting.
TES
.LONG TERM... (Friday through Wednesday)
Issued at 400 AM CST Thu Nov 24 2016
Low level clouds will clear out from west to east on Friday due to
increasing subsidence as a surface ridge builds into the area.
Colder temperatures are expected Friday night due to good
radiational cooling with a clear sky and light surface winds along
surface ridge axis. Lows Friday night will be at or slightly below
normal for late November. Warmer, above normal temperatures are
expected for the weekend beginning Saturday afternoon as an upper
level ridge shifts eastward into the central US, and the surface
wind becomes southerly as the surface ridge shifts east of the
region. Showers will spread into parts of northeast and central MO
and west central IL Sunday afternoon as low level temperature and
moisture advection increase over the area ahead of an upper level
low and associated surface low pressure system moving east-
northeastward into the northern Plains. Showers will shift through
the rest of the forecast area Sunday night with the best coverage
across west central IL as the storm system moves eastward through
the northern Plains with low level moisture convergence across this
area on the nose of a strong southwest low level jet. Showers will
continue Monday and Monday night, particularly across southeast MO
and southwest IL as a southern stream shortwave approaches from the
southern Plains and induces a surface wave along a nearly stationary
front across this area. Will continue pops on Tuesday, although the
model solutions differ with the ECMWF model shifting the
precipitation east of the forecast area by this time, while the GFS
is stronger/deeper and slower with the surface low moving
northeastward along the surface front and keeps precipitation going
across the southeast half of our forecast area through Tuesday. A
cooling trend is expected Tuesday through Wednesday as colder air
continues to filter southeastward into our area as a deepening upper
level trough shifts slowly eastward over the region.
GKS
&&
.AVIATION... (For the 06z TAFs through 06z Thursday Night)
Issued at 1139 PM CST Wed Nov 23 2016
Expect MVFR flight conditions with ceilings between 1000-2000FT to
continue to prevail through the night and into Thursday morning.
Ceilings will clear from southwest to northeast during the
afternoon as the low level flow turns to the south and warmer air
filters into the area.
SPECIFICS FOR KSTL:
MVFR ceilings will continue to prevail at Lambert until at least
early to mid afternoon. Ceilings will clear from southwest as the
wind turns southerly and warmer air filters into the area.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1111 PM CST Wed Nov 23 2016
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...
06Z issuance...VFR conditions through 25.06z. MVFR visibilities late
tonight through early thu morning. Lower visibilities mostly ahead
and along a weakening frontal boundary approaching from the
northwest. Winds will be southwest diminishing to 3 to 5 kts late
this evening and overnight then shifting south to southwest at 5 to 8
knots during the day on thu. 32/ee
&&
.PREV DISCUSSION... /issued 550 PM CST Wed Nov 23 2016/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...
00Z issuance...VFR conditions through this evening followed by MVFR
cigs and visibilities later tonight and early thu morning followed
by vfr cigs through 25.00. Lower cloud bases and visibilities mostly
ahead and along a weakening frontal boundary approaching from the
northwest. Winds will be southeast to south at 5 to 8 kt through
early this evening shifting southwest diminishing to 3 to 5 kts late
this evening and overnight then shifting south to southwest at 5 to
8 knots during the day on thu. 32/ee
PREV DISCUSSION... /issued 413 PM CST Wed Nov 23 2016/
NEAR TERM /Now Through Thursday/...Upper air map analysis shows a
sharp trof axis moving eastward around 25 knots across the
Mississippi River Valley. Within the trof axis, a surface front was
also positioned in the same areas mentioned above. A north to south
zone of precipitable water values (above the mean) extends from the
Upper Mid-West to the western Gulf. Within this zone, precipitable
water values from 1.1 to 1.4 inches, moving into the Lower
Mississippi River Valley, lies between 130 to 160% of normal.
Satellite trends indicate that clouds will be on the increase and
thicken in the near term as the frontal zone approaches from the
west. Although there is moisture available, a rapid movement of the
better dynamics across the local area and the high level energy
dampening a bit, frontal ascent weakens through Thursday suggesting
showers will be lowering to isolated coverages at best in the near
term. This is already being observed in radar with returns moving
eastward across southern Mississippi and southeast Louisiana. These
trends also noted in high resolution HRRR and 4KM NAM output.
Precipitation amounts look light, mostly less than 5 hundredths of an
inch. There is also a signal in the high resolution NAM12 and the
SREF of showing increased probabilities of developing late night fog.
Visibility could be reduced to less than a mile at times. Overnight
lows in the mid 50s interior to lower 60s coast. Daytime highs on
Thanksgiving Day mostly in the mid ranges of the 70s. /10
SHORT TERM /Thursday night Through Saturday night/...An upper level
ridge of high pressure will gradually shift eastward over the
southeastern U.S. and western Atlantic Ocean Thursday night into
Friday as a weak shortwave trough translates toward the Ohio and
Tennessee River Valley region. An associated weak cold front will
push southeastward into our forecast area during the day Friday.
Moisture and lift ahead of this boundary will be very limited, but
there may be just enough available to aid in the development of a few
isolated light rain showers early Friday morning. Lows Thursday night
should range from the upper 40s to mid 50s over most interior areas,
with upper 50s to lower 60s expected near the immediate coast. Highs
Friday should warm into the 70s area wide.
Surface high pressure will build from the Southern Plains to the
Mississippi and Tennessee Valley region Friday night into Saturday,
then across the southeastern states Saturday night. No precipitation
is expected during this time frame as a deeply dry airmass settles
into the region. Clearing skies and cooler temperatures are expected
Friday night through Saturday night. Lows Friday night should range
from the lower to mid 40s inland to the lower to mid 50s coast. Highs
Saturday should range from the mid 60s to around 70. Lows Saturday
night trend a little cooler in the mid 30s to around 40 over the
interior to the mid 40s to around 50 near the immediate coast and
beaches. /21
LONG TERM /Sunday Through Wednesday/...The operational 12Z runs of
the GFS and ECMWF have come into fairly decent agreement in their
solutions with the evolution of the upper air pattern late this
weekend into early next week. Dry weather is expected to continue
across the forecast area Sunday as shortwave ridging aloft builds
from the western Gulf of Mexico to the Great Lakes. Upper ridging
is then forecast to shift eastward over the southeastern U.S. and
into the western Atlantic Ocean early next week as a broad longwave
trough deepens over much of the central CONUS Monday and Tuesday.
Surface high pressure will also subsequently shift from the eastern
U.S. into the western Atlantic early next week as surface low
pressure deepens and lifts northeastward across the northern Plains
and Great Lakes region. A surface cold front should subsequently
advance eastward toward the Mississippi Valley and Gulf Coast states
Monday into Tuesday.
The GFS and ECMWF both show an organized area of convection
advancing eastward toward our forecast area along and ahead of the
cold front sometime during the Tuesday-Tuesday night time frame as a
fairly potent shortwave trough advances eastward toward the
Mississippi and Tennessee Valley region. A low CAPE/high shear
environment will likely be in place over our area ahead of these
approaching features, with MLCAPE values between 250-500 J/KG per the
latest GFS, a developing 45-60 kt low level jet, and increasing
0-1km helicity values between 200-400 m2/s2. It therefore looks like
we will have to monitor for severe weather potential as convection
rolls into the area Tuesday. Otherwise, this system is looking like
it will bring the best chance of rain to our area in a good long
while. We have POPs trending upward to 20-30% with potential for
isolated to scattered warm advection showers Monday-Monday night,
with 50-60% POPs on tap for Tuesday. Rain chances currently appear to
decrease Tuesday night into Wednesday as the cold front moves east of
the region. /21
MARINE...A weakening front approaches the lower Mississippi River
Valley tonight and begins to slow across the central Gulf Coast
region on Thursday. The front makes passage by Friday morning. A
light onshore flow is forecast thru Thursday with winds shifting to
westerly then northerly behind the front Friday. High pressure builds
back into the Southeast US over the weekend, establishing a light
return flow off the Gulf by later in the day Sunday. A more potent
storm system moving across the plains on Monday, combined with high
pressure over the southeast results in a strengthening onshore flow
and building seas early next week. /10
CLIMATOLOGY...A lengthy period of abnormally dry conditions has
resulted in worsening drought conditions over the central Gulf coast.
Since September 27th, Mobile Regional Airport went through a bone-dry
spell of 42 consecutive days with no measurable rain and 41 days at
Pensacola before it finally rained again on November 8th. As it
stands to this date since September 27th, 56 days at Evergreen
straight, without measurable rain. Current annual rainfall deficits
stand at between 6 and 9 inches below normal. Drought has worsened
with severe to extreme drought conditions being experienced over the
local area. A more potent storm system impacting the area early next
week brings the most promising rain potential seen in quite some
time, but this system looks to be progressing eastward rapidly
enough as to do very little in placing a significant dent in the
drought. Stay tuned. /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 Omaha/Valley NE
404 AM CST Thu Nov 24 2016
.SHORT TERM...(today through Saturday)
Issued at 345 AM CST Thu Nov 24 2016
Thanksgiving forecast concerns through the evening will be
cloudcover, temperatures, and light precipitation/precip type
through early evening.
Water vapor satellite imagery showed some enhanced mid level
moisture from north to south ahead of a longwave trough from
MT/WY/CO/AZ. Earlier in the evening, there was some lightning
ahead of the h5 shortwave over UT. WSR-88D reflectivities and obs
are picking us some snow over southeast WY/northern CO. This is
coincident with where the max omega and steepest lapse rates are.
The 130kt h3 jet was a little stronger than progged yesterday.
This jet will quickly work across Nebraska and into Iowa today
advancing the trough.
An extensive area of stratus was located across the forecast area.
This was in an area of high pressure with weak low level flow,
temperatures in the 30s and dewpoints in the 30s. Although not at
the obs, while driving around in the evening and on the way to
work, there was some light patchy drizzle. Surface low pressure
extended from Wyoming through Colorado.
Through today and early this evening lift increases with
steepening lapse rates with the progress of the longwave trough
and the short range models bring a local maximum of vorticity
across the forecast area. The models vary in if there will be
sufficient moisture for precipitation as well as the details of
where the best chance is. The GFS is mostly dry while the the NAM
has a quarter of an inch near the SD border. The EC is in
between. The latest hi-res SPC HRRR has light precipitation by
noon in northeast Neb in advance of the wave and continuing on a
sct basis through the afternoon and spreading southward to south
of Norfolk. The RAP/ESRL HRRR/SPC SREF are similar and have some
light precip as farther south...as far as Falls City and
northwest MO.
Have increasing pops this morning in northeast Nebraska with a
chance for rain or a rain/snow mix and continue this afternoon
with light precip exiting the area by 02Z or 03Z. For now did not
mention much for amounts and the short term forecaster will have
to assess how this is going.
Little temperature change today with highs in the 30s north and
40s south. Lowered highs due to extensive cloud cover. There may
be some breaks in the clouds near the KS border and temperatures
could be a little warmer there.
Decreasing clouds tonight with northwest winds, drier dewpoints
and subsidence behind the shortwave. Friday should be a bit warmer
in the 40s and 50s with more sunshine and Saturday warmer still
with the mid level ridge over the area.
.LONG TERM...(Saturday night through Wednesday)
Issued at 345 AM CST Thu Nov 24 2016
The mid tropospheric ridge will give way to lowering heights as
the Interior West trough moves into the Rockies. The low level jet
is forecast to strengthen from 20kts to Sunday at 12Z to 45kts by
00Z, transporting 7-9deg C h85 dewpoints northward into the
forecast area. Temperatures will be mild, however there will be increasing
clouds and some showers and possibly a rumble of thunder. The
track of the h5 low is well to the west...somewhere over SD/ND
with surface low pressure over CO tracking across Kansas into
central Neb by 00z Sunday evening to a 980/988MB low over
southeast SD by 06z. Colder air does get pulled in and depending
on how far north the system has shifted, some light snow may try
to work into northeast Nebraska and northwest Iowa Monday, or it
may be north of the area.
Sunday highs should be in the 50s with breezy to windy south winds
at 15 to 30 mph and gusty. Preliminary rain amounts would be a
trace to a quarter of an inch.
Cooler for Monday with highs in the 40s and 50s. Reinforcing cold
air will build in for Tuesday/Wednesday with highs in the 30s and
40s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1055 PM CST Wed Nov 23 2016
Expect clouds to hold at all three TAF sites overnight with
ceilings mainly from 800 to 1500 feet. Some fog will likely form
on the edge of the clearing farther west...but probably not
drop to IFR at KOFK or KLNK. Added mention of precipitation in a
tempo group for KOFK and have a prob group for KOMA. Chances at
KLNK seemed too low to mention for now.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Miller
Area Forecast Discussion
National Weather Service Portland Oregon
932 PM PST Wed Nov 23 2016
.SYNOPSIS...An active weather pattern will bring periods of valley
rain, mountain snow and windy conditions at the coast for the next
several days.
&&
.SHORT TERM...Tonight through Friday...Water vapor satellite imagery
reveals an impressive shortwave trough encompassing much of the Gulf
of Alaska this evening. Infrared satellite imagery shows plenty of
cooling cloud tops off the Pacific Northwest coast due to large scale
lift ahead of the shortwave trough and an advancing low level front.
A strong jet on the backside of the trough is beginning to result in
the shortwave trough digging. This will result in the approaching
front to become more oriented from southwest to northeast as it drops
southeastward across the area late tonight and Thursday.
A conditionally unstable airmass has led to numerous showers this
evening across the region. 3 hourly QPF has been relatively light
with just a couple hundredths of an inch in the Willamette Valley and
upwards of a quarter inch in the wettest spots near the coast and in
the Cascades. Snow levels continue to hover around 3500-4000` per
surface observations in the Cascades. It should be noted that
temperatures have fallen across the upper Hood River valley and we
could see precipitation begin to mix with snow above 2000-2500 ft
later tonight and Thursday morning. The NAM & WRF-ARW wet bulb zero
heights support this idea as cold air banks up against the Cascades.
Do not foresee major accumulations at these elevations, but still
something worth monitoring.
Relatively mild ocean temperatures have resulted in convection
continuing off the coast this evening. Given the high shear
environment, a few of these cells have shown some modest rotation a
couple thousand feet AGL so will continue to monitor radar the next
few hours. Mid level warm advection should diminish this threat
fairly quickly later this evening.
Gale force winds have spread across the waters in advance of an
approaching cold front. This cold front is beginning to make an
appearance on the KLGX radar in the form of a disorganized band of
higher echoes ~50 miles off the WA coast. Expect winds to strengthen
across the waters in advance of this front and then spread onto our
beaches and headlands towards midnight, particularly along the Oregon
coast. Pressure gradients remain oriented pretty offshore during this
event so it will be difficult for the strongest winds to reach the
coastline, but we should still see a few gusts around 60 mph in our
more exposed locations along the central & north Oregon coastline.
The current high wind warning covers this well.
Convergence along the front will continue to be quite strong. This
will likely produce a narrow band of locally heavy rain that will
slowly drop southeastward across the region on Thursday morning.
Interestingly, this atmospheric river event is not all that unusual
for this time of year in terms of return intervals for PW and IVT
values so it will likely take the front sitting over a basin or area
to produce higher rain totals. With that said, the NCAR Ensemble
puts greater than a 50% chance of seeing 1-hourly rainfall rates in
excess of 0.50" along portions of the coast Thursday afternoon. Even
the raw 1 hourly GFS output suggests rainfall rates will likely peak
out between 0.30"-0.50" along the coast. While our river basins can
handle an hour or two of these rainfall rates, if these rates
persist over any basin for more than a couple hours, the odds of a
river or two reaching minor flood stage increase dramatically. And
this is where the uncertainty lies...
Models have varied considerably on how fast this front will drop
southeastward across the area, which has led to considerable
uncertainty in the QPF and river forecasts. The GEM, EC & WRF-ARW
models hold the heaviest QPF over the Nehalem, Wilson, Nestucca &
Siletz River Basins on Thursday while the latest GFS & HRRR runs
suggest the front will likely drop southward through Thursday morning
and end up over the Alsea and Siuslaw River drainages by midday. The
GFS & HRRR runs would be less likely to produce river flooding as the
heaviest rainfall would likely not sit over any given drainage too
long. However, it`s hard to ignore the EC & GEM solutions so will
keep the current flood watch as is for now.
An embedded shortwave currently out near 150W will race towards the
region Thursday afternoon and evening. The EC and the GEM to some
degree insist this will remain an open wave while the GFS and its
followers such as the NAM, suggest a surface low pressure will deepen
to around 995mb and move northeastward towards the Washington coast
Thursday night. This latter scenario would likely bring a secondary
bout of high winds to our coastal zones Thursday evening while the
former scenario will increase winds along our coast during this
time, but not likely to high wind levels. Given the position of this
shortwave relative to the jet, a weaker and more open wave seem more
plausible, but confidence is certainly not high this will be the
case. As a result, will keep the high wind watch intact for our
coastal zones for Thursday evening.
Meanwhile, all this rain will fall in the form of snow across the
higher elevations Thursday and Thursday night. However, snow levels
will vary quite a bit across the Cascades during this time. Cold air
will likely be stubborn to scour out across the south Washington
Cascades especially near Mt Adams where 10-20" of snow appear likely
to fall above 3500` and somewhere between 15-30" above 4500`. Farther
south, warm air streaming northeastward ahead of the front should
result in snow levels rising to ~4500` Thursday afternoon and evening
across the Oregon Cascades. This process will be slowest to occur
near Mt Hood so the current Winter Wx Advisory looks on track. The
good news is that this should bring a period of improved travel
conditions for those traveling across the Cascade passes on Thursday.
Cool, but substantially quieter weather will likely follow on Friday
before more showers produce valley rain and mountain snow showers
above 3500-4000 feet Saturday and Saturday night. /Neuman
.LONG TERM...(Saturday night through Wednesday)...No Changes...
Previous Discussion from Wednesday afternoon follows...The active
weather pattern looks to continue through much of the long term
forecast as a series of storm systems move across the Pac NW. Models
continue to show an upper level trough moving across the forecast
area Saturday night and Sunday which will maintain showers over the
region. Snow levels look to lower to around 2500 ft on Sunday, with
an additional 3 to 6 inches possible at the Cascade passes. If you
are planning on traveling over the Cascades, prepare for hazardous
road conditions.
Models then show a weak upper level shortwave dropping southeastward
Sunday night and Monday. This system looks to bring another round of
rain to the area late Sunday/early Monday, with cool northwesterly
flow keeping showers going on Monday. High pressure looks to build
across the area Monday night and Tuesday bring with it a period of
quieter weather and raising snow levels to around 4500 ft. However,
this bring will be short as models show another upper level trough
dropping south out of the Gulf of Alaska Tuesday night and Wednesday
which could bring another round of heavy rain and Cascade snow, with
locally windy conditions. /64
&&
.AVIATION...Little change over the last several hours where
mainly VFR conditions prevail this evening with occasional dips to
MVFR both inland and at the coast. By later this evening most
terminals will drop to MVFR as the next slug of moisture moves
towards the area. Probably not much change to the MVFR Cigs for
much of Thursday. Cigs may rise back to VFR for several hours
Later Thursday afternoon and early evening.
Prefrontal winds have been underwhelming thus far but should
increase as the cold front approaches. Expect strongest southerly
frontal wind gusts along the coast near KONP around 40 knots and
around 30 knots at KAST. Should see 25 to maybe brief 30 knots for
the inland terminals peaking around 12Z with 20 to 25 knot gusts
the norm for the several hours around that. South winds appear to
increase again with gusts 30 to 40 knots Thursday afternoon and
evening but there is significant model uncertainty regarding the
track of a potential surface low and even it`s possible existence
versus on open surface trough.
KPDX AND APPROACHES...Conditions will bounce between MVFR and VFR
this evening before settling to VFR for most of the overnight
period. Lower cigs are not expected until Thursday afternoon as
the front approaches. Winds will increase overnight and peak 20g30
knots around 12Z Thu plus another possible similar peak after
25/04z. JBonk/Bentley
&&
.MARINE...Gale gusts are underway at the inner buoys and am
eagerly waiting on an evening ASCAT pass to confirm the potential
for the outer waters. Offshore flow still dominates the near
shore waters where small craft advisory winds appear to be the
norm for now. Have seen sporadic gusts 35-40 kt under convective
showers embedded within the rain bands. This is still covered by
the ongoing gale warning. The cold front is sitting just outside
of the coastal waters at this hour and will move east- southeast
over the next 5-7 hours reaching the Columbia mouth somewhere
around 3-5 am PST. Do expect the strongest winds will occur for a
couple hour period with the frontal passage. Latest hi- resolution
models hint there may be occasional gusts 45-50 knots with the
frontal passage. Given the brief and marginal nature, cannot
justify issuing a storm warning for tonight`s frontal passage.
Seas at buoy 46005 peaked at 23 feet several hours ago and was
likely driven by the local wind waves for a brief time before
settling down to around 20 feet for the following few hours.
Typical wave decay would bring that westerly swell in at 18-20
feet which remains in line with the current forecast for later
tonight. winds behind the front will drop of dramatically but
still likely sit in the SCA realm. The central waters, however,
have a chance at seeing low end gale gusts through the day
Thursday.
00z models have done little to change confidence fro the next
system to affect the waters later Thursday afternoon and Thursday
evening. The track and strength of this second system keeps
changing in small but impactful ways, leading to more uncertainty
with this second system. Have left the forecast from the previous
shift in place which would bring another round of gales, with a
chance for storm-force winds especially south of the Columbia
River Thursday evening and decreasing around 10pm Thursday night.
Have, unfortunately, still left the storm force watch in place
with the hopes the current front and the expected additional
satellite derived wind data will provide a clear picture. If a
choice had to be made right now, would be inclined to drop the
storm watch and go with a strongly worded gale warning...similar
to the current one with gusts primarily 40-45 kt and the
occasional gusts 50-55 kt possible. The current forecast would
bring seas back up to 20 to 25 ft Thursday evening with seas
starting to fall back down after the winds start to subside after
10pm Thursday night. Keep an eye on the forecast for this system
as it is subject to change.
Friday things start to calm down, with winds and seas coming back
down. Still think we will see small craft advisory winds through
most of the day on Friday, though winds should drop below 20 kt
by Friday evening. Seas should drop back down into the mid-teens
by Friday evening as well. Weaker fronts move across the waters
over the weekend, but generally seas expected to drop to around 9 ft
by Saturday night or Sunday, and winds stay fairly benign for this
time of year. JBonk/McCoy
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory from 4 AM Thursday to 4 AM PST Friday
for Northern Oregon Cascades.
High Wind Warning from 1 AM to 10 AM PST Thursday for Central
Oregon Coast-North Oregon Coast.
Flood Watch from Thursday morning through Friday evening for
Central Coast Range of Western Oregon-Central Oregon Coast-
Central Willamette Valley-Coast Range of Northwest Oregon-
Greater Portland Metro Area-North Oregon Coast-South
Willamette Valley.
High Wind Watch from Thursday afternoon through Thursday
evening for Central Oregon Coast-North Oregon Coast.
WA...Winter Storm Warning from 1 AM Thursday to 4 AM PST Friday for
South Washington Cascades.
Flood Watch from Thursday morning through Friday evening for
South Washington Coast.
High Wind Watch from Thursday afternoon through Thursday
evening for South Washington Coast.
PZ...Storm Watch from Thursday morning through Thursday evening for
Coastal Waters from Cape Shoalwater WA to Florence OR out
60 nm.
Gale Warning until 10 AM PST Thursday for Coastal Waters from
Cape Shoalwater WA to Florence OR out 60 nm.
Small Craft Advisory for Rough Columbia River Bar until 4 PM
PST Thursday.
&&
$$
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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. The area is
commonly referred to as the forecast area.
Area Forecast Discussion
National Weather Service Tulsa OK
337 AM CST Thu Nov 24 2016
.DISCUSSION...
Fog potential through mid to late morning is the primary forecast
concern. So far early this morning, any fog has been very patchy
and also very short lived at any one site. Both the experimental
and operational HRRR indicate this changing prior to sunrise
across portions of eastern Oklahoma and into the Arkansas River
Valley, in the cleared area on the western edge of the surface
ridge. Confidence is not high enough at this point to issue a
Dense Fog Advisory but we are prepared to issue one if
observations begin to support it. In addition to the dense fog
potential, a couple of sites have briefly reported freezing fog,
and as such, will include a patchy mention of freezing fog
generally from Claremore to Tahlequah to Sallisaw.
Southerly winds will return today as the surface ridge pushes to
the east, leading to above normal temperatures today. A fairly
fast moving, dry cold front will push through the region tonight,
with a brief decrease in temperatures following on Friday. Saturday
will be largely quiet with slightly warmer temperatures.
The next big weather maker will begin to affect the region Sunday
and into the early part of next week. Flow in advance of a large
trough over the western half of the country will lead to
increasing deep layer moisture and a resulting increase in shower
and thunderstorm potential. While activity should generally remain
scattered across the area into Sunday evening, better chances,
with some locally heavy rain potential, should arrive with a cold
front early Monday morning and into the day. Southeast Oklahoma
and into western Arkansas look to have the best shower and
thunderstorm potential during this time frame. The medium range
models differ somewhat with the handling of the system after
Monday, with the GFS lingering the front across the southeastern
half of the area, leading to rain chances into Monday night and
early Tuesday, whereas the ECMWF is more progressive with this
feature.
Much cooler temperatures and dry conditions will prevail toward
the middle of next week on the heels of the departing front.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 66 38 60 33 / 0 0 0 0
FSM 65 39 61 33 / 0 0 0 0
MLC 66 40 61 33 / 0 0 0 0
BVO 64 35 59 26 / 0 0 0 0
FYV 62 34 57 25 / 0 0 0 0
BYV 59 38 56 31 / 0 0 0 0
MKO 64 37 58 31 / 0 0 0 0
MIO 60 35 55 30 / 0 0 0 0
F10 65 38 59 33 / 0 0 0 0
HHW 66 41 62 35 / 0 0 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
LONG TERM....22
Area Forecast Discussion
National Weather Service Dodge City KS
606 AM CST Thu Nov 24 2016
.UPDATE...
Issued at 606 AM CST Thu Nov 24 2016
Updated to include areas of fog across more of the eastern CWA
this morning, and to increase sky cover to account for thickening
cirrus this morning. No other changes.
&&
.SHORT TERM...(Today and tonight)
Issued at 254 AM CST Thu Nov 24 2016
We will need to watch the areas around Hays early this morning for
the potential of fog or stratus development, as the latest fog
channel imagery has been indicating this across Rooks county. The
HRRR fields however suggest that will not occur at this time. Going
foreword, a vigourous shortwave will drive a pacific surface cold
front into the High Plains region later this morning. The short wave
vort lobe will be moving across the area just behind the front,
adding to subsidence and helping create strong northwest winds
sustained to 30 mph and higher gusts. Surface winds weaken rapidly
with the loss of insolation. Not alot of variance in the model
lows tonight, however MOS products are generally cooler in the
teens across the higher elevation far western counties.
.LONG TERM...(Friday through Wednesday)
Issued at 254 AM CST Thu Nov 24 2016
The large scale pattern will remain progressive in the medium range.
Between the ECMWF and GFS there appears to be a general agreement on
a large trough developing in the west, and a closed low most likely
to move into the Northern Plains around the end of the weekend.
This won`t rule out our area for seeing clouds and even a
possibility for precipitation, however the main forcing mechanisms
near the warm front would be too far north in the upper midwest
with these model runs. As the low develops to the north, Sunday
looks to be a particularly windy day with a strong surface
pressure gradient and strong subsidence aloft. The region could
remain in cyclonic flow aloft easily through mid week, supporting
generally cold temperatures (cooler than climo highs).
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 500 AM CST Thu Nov 24 2016
VFR with scattered cirrus expected through 12z Fri. The only
possible exception to this is a few hours of BR and/or stratus
at/near HYS this morning. Satellite imagery reveals widespread
stratus/fog north and east of the HYS terminal this morning, with
a general westward drift noted. RSL already reporting LIFR cigs.
Given this, included a TEMPO group for IFR or lower cigs at HYS
and reduced vis in BR. Strong shortwave will pass just north of SW
KS this afternoon, forcing a dry cold frontal passage across the
airports with strong gusty NW winds. NW winds will average 22-32
kts, with the strongest winds at GCK and the least at HYS. NW
winds will relax quickly around sunset.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 59 27 58 31 / 0 0 0 0
GCK 57 23 58 27 / 0 0 0 0
EHA 58 26 58 30 / 0 0 0 0
LBL 61 24 58 29 / 0 0 0 0
HYS 55 28 58 30 / 0 0 0 0
P28 63 32 59 32 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Turner
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Turner
Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
854 AM CST Thu Nov 24 2016
.UPDATE...
Issued at 854 AM CST Thu Nov 24 2016
Updated precipitation types and POPs to attempt to account for the
lake effect showers over portions of northwest Wisconsin this
morning. DLHWRF and RAP data suggest the low-level flow will back
northwesterly later this morning and into this afternoon. That
wind shift should change the one or two bands at present to
multiple, weaker bands later this morning with a northwest to
southeast orientation. Thermal profiles using lake temperatures of
45 degrees yield equilibrium levels below -10 degrees C, with
drier air farther aloft. It would seem ice crystal seeding is
difficult to achieve with these parameters and reports from
spotters indicate either -RA or DZ this morning. Updated precip
types to lean more heavily on the -RA/ZR potential through this
afternoon. Increased QPF by a few hundredths given the intensity
of the returns.
UPDATE Issued at 622 AM CST Thu Nov 24 2016
Updated to remove early morning wording and adjust POPs along
south shore in NW WI to account for the continuing precip band off
the lake. The area is slowly shrinking in area but will continue
into mid-morning.
UPDATE Issued at 543 AM CST Thu Nov 24 2016
Updated for the new 12Z Aviation Discussion below.
&&
.SHORT TERM...(Today through Friday)
Issued at 340 AM CST Thu Nov 24 2016
Main concerns for short term is a snow band this morning along
the south shore of Lake Superior and chances/Ptype tonight.
Current surface analysis indicates a precip band extending NE to
SW across eastern Douglas and Western Bayfield counties early this
morning. It is caused by an area of convergence in the area with
north winds from MN converging with NE winds along the lake. The
band is probably snow with some rain mixed in at times. Surface
obs in the affected area indicates temps 33-35 so there could be
mixture. There has been a slow eastward movement with the band.
Will put in up to a half of an inch of snow this morning. The band
will continue to move east and dissipate by mid-morning as the
convergence decreases.
Will keep fog in across most of the region this morning. With the
low clouds and abundant moisture in the low levels along with fog
being reported at some ob sites, fog will be a good bet.
The next concern will be a shortwave trough that will move across
the forecast area this tonight and early Friday morning. As
indicated by the previous shift, with the moisture in the region
along with some forcing and seeding from cirrus into the lower
levels, there could a possibility of snow showers along with some
possible freezing drizzle. It still looks the best chance for the
freezing drizzle will be in NW WI.
An area of high pressure will build into the region on Friday
which may bring some breaks in the clouds and near normal
temperatures.
.LONG TERM...(Friday night through Wednesday)
Issued at 340 AM CST Thu Nov 24 2016
The focus remains on a potential strong area of low pressure that
will likely affect the Northern Plains and Upper Midwest early next
week, potentially bringing the Northland periods of rain and snow
Sunday night through the middle of the week. The latest model runs
maintained a more northern low track and warmer temperatures,
compared to the model runs from 24 hours earlier, so it still
appears the pcpn will be more rain than snow, at least at first.
There should still be a transition to more snow than rain by the
middle of the week.
An upper-level ridge will build into the Upper Midwest this
weekend, with southerly flow pumping warmer air into the region.
Temperatures will increase to nearly 10 degrees above seasonal
normals, with highs well into the 30s Saturday and Sunday. This
will help melt any lingering snow and ice off the roads from the
recent rounds of snow.
A fast moving wave is expected to lift from the southwest US early
Sunday into the Great Plains Sunday and Sunday night. It will
develop a stacked low near eastern Colorado and lift into the
eastern Dakotas and/or Minnesota Monday. The low will bring a surge
of moisture into the Northland Sunday night and Monday, probably
mostly in the form of rain given the relatively warm temperatures
aloft. Think the threat of freezing rain is very low because the
cloud cover and moisture will help temperatures remain or rebound to
near or above freezing. This low track is farther north than earlier
runs, which is part of the reason for the greater favorability of
rain than snow. However, colder air will likely develop or filter
into the region towards the middle of the week, and possibly result
in periods of light to moderate snow Monday night through Wednesday.
The Canadian and GFS are much faster at pulling out the low than the
ECMWF, which lingers the low over Minnesota well into Wednesday, so
there is greater uncertainty for the weather for the middle of the
week.
At this time, not overly concerned about headline-worthy snowfall for
this coming storm system, as long as this latest more north track
and warmer air trend continues with subsequent model runs. Periods
of rain and melting will probably give breaks between the snowfall
accumulations.
Temperatures will likely return to about 5 degrees above normal by
Wednesday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 543 AM CST Thu Nov 24 2016
Widespread IFR/MVFR conditions are expected across northeast
Minnesota and northwest Wisconsin through tonight. Expect low
ceilings, very light wind flow, and occasional times of LIFR
ceilings.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 35 28 34 26 / 20 20 10 10
INL 34 25 34 23 / 20 20 10 10
BRD 34 27 35 23 / 20 30 10 0
HYR 36 27 35 23 / 20 30 10 10
ASX 38 29 36 26 / 60 30 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...Huyck/Stewart
SHORT TERM...Stewart
LONG TERM...Grochocinski
AVIATION...Grochocinski
Area Forecast Discussion
National Weather Service Gray ME
1043 AM EST Thu Nov 24 2016
.SYNOPSIS...
High pressure will crest over the region early this morning before
sliding offshore. A weakening area of low pressure will approach from
the west later today and tonight before passing out to sea to our
south. Another area of weak low pressure will approach from the
west on Friday and will push into New England Friday night. A
trough of low pressure will remain over the region on Saturday
through Sunday. High pressure will build in from the west Sunday
night and Monday. High pressure will crest over the region Monday
night and will shift off to the east on Tuesday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE 2...continue to tweak pops and raised max temps a degree or
two for today. Area of over running precip moving through the
forecast area. snow is light and should not accumulate much today.
The GYX sounding this morning was very dry in the mid levels so
much of what is on radar is evaporating as it falls.
Prev Disc...
At 07z...a 1029 millibar surface ridge was draped across New
England. A 1012 millibar low was centered over the Great Lakes.
GOES imagery showed lingering low cloud across the Connecticut
valley northward through the international border area. Middle and
high clouds were advancing rapidly eastward from the Great Lakes
ahead of a shortwave impulse situated over the upper midwest and
Great Lakes. For today...the surface ridge will slide offshore
this morning. Thicker clouds will arrive from west to east later
this morning in weak warm air advection ahead of the shortwave
impulse. NWS doppler radar mosaic showed a band of mixed precipitation
associated with this disturbance over the eastern Great Lakes at
moment. This precipitation should arrive during the afternoon and
evening hours with HRRR and other short term numericals placing
the bulk of the QPF...albeit light over the northern half of New
Hampshire into adjacent western Maine. Forecast soundings are cold
enough for frozen precipitation today...with the exception of where
the precipitation is extremely light and boundary layer temperatures
are several degrees above freezing with some rain or a rain/wet
snow mix possible. High temperatures today will be limited to the
30s by clouds and precipitation. Snow accumulations later today
should be an inch or two for the higher terrain with less than an
inch elsewhere.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
For tonight...snow tapers to scattered flurries as the weakening
shortwave impulse exits the area to our east overnight. With loss
of ice crystals we may also see some patchy drizzle and freezing
drizzle overnight depending on surface temperatures. On
Friday...we have a quiet start as we are initially between disturbances
with clouds and scattered flurries along with some patchy drizzle
or freezing drizzle. By afternoon...the next weak disturbance will
be approaching from the Great Lakes with the next batch of warm
air advection precipitation arriving. High temperatures will range
from 30s in the mountains to near 40 elsewhere. Any light accumulating
snows should be limited to the higher terrain...while we`ll see a
rain/snow mix elsewhere.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Low pressure will develop/strengthen near Nantucket Island Friday
night and move northeastward on Saturday as potent short wave
trough approaches from the west. As this occurs, at least light
precipitation should develop across the CWA. At this time, the
thermal profile across much of the CWA supports rainfall, with a
mix and/or snow across the far interior. As secondary mid level
low pressure develops further just to the east of the Maine coast
on Saturday, colder air will filter in from the west and perhaps
change the rain over to snow even on the coastal plain Saturday
evening. At this time it appears as though the best forcing for
ascent will be found to the northeast of our CWA at this time and
this should preclude a major snow event in our CWA. However, it is
worth noting that there is still a good amount of model spread in
short wave trough strength and speed, and this still could have an
effect on mesoscale features at this juncture. Therefore, we still
cannot rule out the occurrence of a brief band accumulating snow
moving across portions of the region between Saturday and Sunday
morning.
Low pressure will move away from the region on Sunday with weak
high pressure building in on Monday. The fair weather will be
short-lived however as there is strong model and ensemble
agreement that that weather will quickly become active again
Tue through Thurs. At this time, low pressure is expected to bring
mainly rainfall then.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
Short Term /Through Friday/...Areas of MVFR ceilings for the
Connecticut valley...then conditions lowering to mvfr with lcl ifr
in snow and rain btw 16 and 22z. Widespread mvfr and areas of ifr
tonight in -shsn and areas of drizzle and fog...with patchy
freezing drizzle.
Long Term...MVFR to IFR conditions are expected Friday night
through Saturday night as low pressure develops off the Maine
coast. Improvement is foreseen on Sunday as low pressure moves
away from the region...with VFR conditions prevailing into
Monday.
&&
.MARINE...
Short Term /Through Friday/...Quiet on the waters with conditions
remaining below small craft as high pressure crosses the waters
today then weak low pressure passes well to the south of the
waters early Friday.
High pressure builds overhead
tonight...allowing winds and seas to continue to diminish. Winds
remain light thru Thu...with conditions expected to remain below
SCA thresholds.
Long Term...SCA conditions are expected Sat night through sun
night as low pressure departs.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
UPDATE...TFH
Area Forecast Discussion
National Weather Service Wilmington NC
906 AM EST Thu Nov 24 2016
.SYNOPSIS...
High pressure will settle offshore this afternoon ahead of a
cold front that will cross the coast Friday. Much cooler air
will move into the region this weekend into early next week. A
warming trend develops Tuesday ahead of another cold front. This
front will bring a good chance of rain by the middle of next
week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 9 AM Thursday...The upper-level disturbance continues to
move to the east and at 12 UTC it was located from Lake Superior
to central North Carolina. The 06 UTC runs of the GFS continue
to show this feature off the coast by 18 UTC. Associated with
this wave is isolated showers mainly north of Lumberton to
Burgaw, and the HRRR is not showing an extension of these
showers to the South so expect the threat of any precipitation
will diminish.
As the short-wave shifts to the east the HRRR confirms the skies
clearing and high temperatures being able to rise in the lower
to mid 70s. Overnight with a strengthening subsidence inversion
aloft, and light low-level winds will set the stage for areas
of fog tonight, mainly after midnight, with lows 50-55.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 300 AM Thursday...A broad area of low pressure off the Mid-
Atlantic and New England coast will deepen into a stronger low off
New England Friday night into Saturday. This should pull a cold
front through the area late Friday night, with the next high
building in from the west Saturday. Expect a partly cloudy sky
Friday with residual low-level moisture and the subsidence inversion
still present up around 7000 feet AGL. It`s even possible that a few
of the daytime cumulus clouds could try to drop some sprinkles given
model progs of up to 100-150 J/kg of surface-based CAPE during mid
afternoon. Highs are expected to again reach 70-75.
Surprisingly, the slightly better chance of showers could arrive
with the cold front itself Friday night. Although moisture depth
will be meager and the bulk of the upper support remains well to the
north, forced lift along the front could produce a broken line of
showers, focused from late evening through about 3 AM. Forecast PoPs
are only 20 percent.
Dry weather and significantly cooler temperatures are expected for
Saturday into Saturday night as Canadian air again spreads southward.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 300 AM Thursday...Cool and dry high pressure over the
Carolinas on Sunday will shift off shore on Monday. A light
northerly flow Sunday morning will become lighter and more
variable through late Sunday, but without any change in air
mass, expect temps on the cool side, with most places not making
it to 60 during the day and dropping down into the 30s Sun
night.
As the high shifts off shore on Monday, a warmer and moister
return flow will set up. Temps will reach into the 60s with
plenty of sunshine. Dewpoint temps will start climbing Mon nigh
into Tues as southerly flow increases through the low to mid
levels. Clouds and shwrs will increase heading into mid week as
a cold front approaches from the west. The ECMWF is a bit slower
to bring the front through, but overall expect the best chc of
rain on Wed with a chance of some decent QPF across most of the
area. Could see pcp water values up over 1.5 inches on Wed.
Plenty of WAA will push temps above normal Tues and Wed.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
As of 12Z...Based on current observational trends and latest MOS
guidance, VFR is likely to continue this morning into this
afternoon. A few showers are possible this morning, mainly NC
terminals, but do not expect anything more than very light. There is
possibility of MVFR cigs around mid-morning, but confidence is low
as cloud layers today should be most predominate in the 4-9k range.
Light winds this morning will gradually increase and become S-SW at
the coastaL terminals and SW-WSW at the inland terminals 5-10 kt.
This evening as winds become light, fog development is likely but
mainly after midnight. Confidence is low but KCRE could have
temporary fog/sub VFR vsbys 3-6z. The best likelihood of dense fog
however should be at KFLO/KLBT after 09z under clear skies.
Lingering cloudiness at the coastal terminals should decrease the
likelihood of IFR.
Extended outlook...VFR condiitons expected through the period.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 9 AM Thursday...The high pressure area has shifted off the
east coast and the southerly winds over the coastal waters is
now established. Wind speeds currently are around 10 knots and
hrrr show this speed to continue with a veering of the wind
direction to the southwest by sunset.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 300 AM Thursday...A broad area of low pressure off the Mid-
Atlantic and New England coast will deepen into a stronger low off
New England Friday night into Saturday. This should pull a cold
front through the area late Friday night, leading to a period of
rather strong northerly winds lasting through most of Saturday. At
this time it appears wind speeds within 20 miles of shore will top
out around 20 knots with some 25 knot gusts around daybreak
Saturday, just below Small Craft Advisory thresholds. Winds should
remain around 15 knots from the north through Saturday night as he
next high builds in from the west.
LONG TERM /SUNDAY THROUGH MONDAY/...
As of 300 AM Thursday...Northerly flow on Sunday will diminish
and become very light and more variable as high pressure
migrates east over the waters through Monday. The center should
be moving off of Hatteras by Mon aftn allowing for a more
persistent on shore flow to set up by late Mon into Tues.
Overall winds will start out 10 to 15 kts Sun morning and then
diminish to under 10 kts Sun night through Mon with a trend
upward late Mon into Tues to 10 to 15 kts out of the E-SE. Seas
will follow similar trend diminishing from 3 to 4 ft on Sun
morning down to less than 2 ft by Mon aftn but rising steadily
Mon night into Tues in increasing on shore push.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
NEAR TERM...HAWKINS/TRA
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...MRR
Area Forecast Discussion
National Weather Service North Platte NE
856 AM CST Thu Nov 24 2016
.UPDATE...
Issued at 856 AM CST Thu Nov 24 2016
A pacific cold front is entering Western Nebraska. The front
should induce mixing...sweep moisture east and lift any remaining
fog. Visibility will continue to improve and the dense fog
advisory will be allowed to expire at 9 am CST.
UPDATE Issued at 547 AM CST Thu Nov 24 2016
The freezing fog advisory has been converted to a dense fog
advisory and expanded west through Chase county until 15z. Do
not be deceived by the improvement in visibility at North Platte
airport. The 200 foot ceiling likely represents 1/4 mile or less
visibility in the highlands north and south of town.
&&
.SHORT TERM...(Today and tonight)
Issued at 333 AM CST Thu Nov 24 2016
Today and Tonight...a weak short wave moving through ncntl Colo this
morning will collide with arctic drape across ncntl Neb producing
scattered rain showers across ncntl Neb. The HRRR...RAP and NAM are
in good agreement lifting a band of showers through Holt county this
afternoon. A pacific cold front moving through cntl WY will sweep
east into the Neb Panhandle this morning and scour out the arctic
air and clouds across ncntl Neb this afternoon.
A blend of bias corrected RAP and HRRR model temperatures produces
highs in the 40s. Bias corrected guidance produces lows in the teens
and 20s tonight under clear skies.
The dense freezing fog this morning is forming mainly on the wrn
fringe of the arctic drape. This hazard is short lived in most
locations but could last several hours this morning according to the
time lapsed HRRR model. Temperatures will gradually warm above
freezing this morning reducing the hazard. The freezing fog advisory
operates until 12z and will be reevaluated at that time for a
possible extension or down-grade to a dense fog advisory.
.LONG TERM...(Friday through Wednesday)
Issued at 333 AM CST Thu Nov 24 2016
Upper level ridging and surface high pressure remain over the region
through Sunday. This ridge will result in dry conditions across
central Nebraska through much of the weekend. In addition,
temperatures will have a brief warm-up this weekend. Highs Friday
start off in the low to mid 50s before rising up into the upper 50s
on Saturday. Cooler temperatures begin to filter into the region on
Sunday with highs only rising into the upper 40s across the north
and into the low 50s across the south.
The next weather system arrives on Sunday night bringing a potential
of some wintry precipitation to central Nebraska. Current model runs
show this system mostly missing the north central Nebraska forecast
area. Just a chance of some rain mainly across Holt and Boyd
counties in the afternoon Sunday. Precipitation will then switch
over to snow, however, the system will be north of the area by then.
Will keep just a slight chance of some snow across the
Nebraska/South Dakota border as moisture wraps around this system
on Sunday night.
The low pressure system moves north and east of the area by Monday
night allowing another weak high pressure system to build northward
into the central Plains for the middle of next week. Temperatures
remain cooler through mid-week with highs only rising into the mid
to upper 30s each day. Lows remain steady from Friday night through
Tuesday night in the mid 20s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 520 AM CST Thu Nov 24 2016
The widespread IFR/LIFR in very low cigs and fog will be swept
east as a pacific cold front moves through western and north
central Nebraska today. VFR is expected all areas around 21z.
Improvements in flight conditions will occur from west to east.
Pacific high pressure will build through the cntl High plains and
Rockies late this aftn and tonight presenting VFR to all areas.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...Kulik
AVIATION...CDC
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
451 AM CST Thu Nov 24 2016
.SHORT TERM... (Through Late Tonight)
Issued at 313 AM CST Thu Nov 24 2016
A weak RIDGE aloft prevails over our region early this morning, with
a light northwest flow at the surface. A surface RIDGE axis extends
from eastern Nebraska into far western Missouri. An expansive area
of low cloudiness exists across much of the Midwest, with its
backedge just to the west of the surface RIDGE axis. This backedge
has not moved over the past several hours. Temperatures were in the
upper 30s to mid 40s across our region.
The 06/07z RAP runs as well as the updated 06z NAM seem to be
handling the low clouds the best and were used as primary guidance.
These models persist the low cloud field across our region into the
afternoon hours with some clearing occurring for some sections south
of Interstate 70 in central and southeast MO. With the low level
RIDGE axis sliding thru late this morning and early afternoon,
advection will be negligible in moving this cloud field and this
being late November, it is unlikely the sun will be able to
dissipate. A light southerly low level flow into central MO and
southeast MO during the afternoon look like the best opportunity for
limited clearing. Max temps will also be cool today for areas near
and north of I-70 where the clouds will persist, with conditional
climatology suggesting a mere 5 degree rise, and have strongly
preferred the MET MOS values in these areas with peak readings in
the 40s. Trended towards the MAV MOS in southern areas, with peak
readings in the low 50s.
Light winds becoming more northerly with time tonight will, if
anything, allow the low cloud field near and north of I-70 to drop
south again and recover lost ground. In addition, an upper level
disturbance will drop thru our region. Models generally show a
decently strong region of broadscale lift and some WAA that will
also bring in thicker ice-containing clouds. The system is rather
fast moving, however, and will work on a very dry column. The
column will be too warm for anything but liquid pcpn, but unless the
system can produce stronger lift than is currently being depicted,
it will be tough to get any pcpn going with this when it moves thru
tonight. Have continued the dry forecast. Went warm on min temps
tonight with lots of clouds persisting.
TES
.LONG TERM... (Friday through Wednesday)
Issued at 400 AM CST Thu Nov 24 2016
Low level clouds will clear out from west to east on Friday due to
increasing subsidence as a surface ridge builds into the area.
Colder temperatures are expected Friday night due to good
radiational cooling with a clear sky and light surface winds along
surface ridge axis. Lows Friday night will be at or slightly below
normal for late November. Warmer, above normal temperatures are
expected for the weekend beginning Saturday afternoon as an upper
level ridge shifts eastward into the central US, and the surface
wind becomes southerly as the surface ridge shifts east of the
region. Showers will spread into parts of northeast and central MO
and west central IL Sunday afternoon as low level temperature and
moisture advection increase over the area ahead of an upper level
low and associated surface low pressure system moving east-
northeastward into the northern Plains. Showers will shift through
the rest of the forecast area Sunday night with the best coverage
across west central IL as the storm system moves eastward through
the northern Plains with low level moisture convergence across this
area on the nose of a strong southwest low level jet. Showers will
continue Monday and Monday night, particularly across southeast MO
and southwest IL as a southern stream shortwave approaches from the
southern Plains and induces a surface wave along a nearly stationary
front across this area. Will continue pops on Tuesday, although the
model solutions differ with the ECMWF model shifting the
precipitation east of the forecast area by this time, while the GFS
is stronger/deeper and slower with the surface low moving
northeastward along the surface front and keeps precipitation going
across the southeast half of our forecast area through Tuesday. A
cooling trend is expected Tuesday through Wednesday as colder air
continues to filter southeastward into our area as a deepening upper
level trough shifts slowly eastward over the region.
GKS
&&
.AVIATION... (For the 12z TAFs through 12z Friday Morning)
Issued at 450 AM CST Thu Nov 24 2016
Expansive cloud shield of MVFR CIGs is expected to persist for the
TAF sites thru much of the valid period with few exceptions.
Otherwise, light NW surface winds will become variable later today
with some improvement to CIGs between 2000-3000 feet as surface
RIDGE moves thru. With a new cold front moving thru late tonight,
this should finally push the low clouds to the east by the end or
just beyond the end of the valid period as surface winds resume
from the west-northwest.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Omaha/Valley NE
538 AM CST Thu Nov 24 2016
.SHORT TERM...(today through Saturday)
Issued at 345 AM CST Thu Nov 24 2016
Thanksgiving forecast concerns through the evening will be
cloudcover, temperatures, and light precipitation/precip type
through early evening.
Water vapor satellite imagery showed some enhanced mid level
moisture from north to south ahead of a longwave trough from
MT/WY/CO/AZ. Earlier in the evening, there was some lightning
ahead of the h5 shortwave over UT. WSR-88D reflectivities and obs
are picking us some snow over southeast WY/northern CO. This is
coincident with where the max omega and steepest lapse rates are.
The 130kt h3 jet was a little stronger than progged yesterday.
This jet will quickly work across Nebraska and into Iowa today
advancing the trough.
An extensive area of stratus was located across the forecast area.
This was in an area of high pressure with weak low level flow,
temperatures in the 30s and dewpoints in the 30s. Although not at
the obs, while driving around in the evening and on the way to
work, there was some light patchy drizzle. Surface low pressure
extended from Wyoming through Colorado.
Through today and early this evening lift increases with
steepening lapse rates with the progress of the longwave trough
and the short range models bring a local maximum of vorticity
across the forecast area. The models vary in if there will be
sufficient moisture for precipitation as well as the details of
where the best chance is. The GFS is mostly dry while the the NAM
has a quarter of an inch near the SD border. The EC is in
between. The latest hi-res SPC HRRR has light precipitation by
noon in northeast Neb in advance of the wave and continuing on a
sct basis through the afternoon and spreading southward to south
of Norfolk. The RAP/ESRL HRRR/SPC SREF are similar and have some
light precip as farther south...as far as Falls City and
northwest MO.
Have increasing pops this morning in northeast Nebraska with a
chance for rain or a rain/snow mix and continue this afternoon
with light precip exiting the area by 02Z or 03Z. For now did not
mention much for amounts and the short term forecaster will have
to assess how this is going.
Little temperature change today with highs in the 30s north and
40s south. Lowered highs due to extensive cloud cover. There may
be some breaks in the clouds near the KS border and temperatures
could be a little warmer there.
Decreasing clouds tonight with northwest winds, drier dewpoints
and subsidence behind the shortwave. Friday should be a bit warmer
in the 40s and 50s with more sunshine and Saturday warmer still
with the mid level ridge over the area.
.LONG TERM...(Saturday night through Wednesday)
Issued at 345 AM CST Thu Nov 24 2016
The mid tropospheric ridge will give way to lowering heights as
the Interior West trough moves into the Rockies. The low level jet
is forecast to strengthen from 20kts to Sunday at 12Z to 45kts by
00Z, transporting 7-9deg C h85 dewpoints northward into the
forecast area. Temperatures will be mild, however there will be increasing
clouds and some showers and possibly a rumble of thunder. The
track of the h5 low is well to the west...somewhere over SD/ND
with surface low pressure over CO tracking across Kansas into
central Neb by 00z Sunday evening to a 980/988MB low over
southeast SD by 06z. Colder air does get pulled in and depending
on how far north the system has shifted, some light snow may try
to work into northeast Nebraska and northwest Iowa Monday, or it
may be north of the area.
Sunday highs should be in the 50s with breezy to windy south winds
at 15 to 30 mph and gusty. Preliminary rain amounts would be a
trace to a quarter of an inch.
Cooler for Monday with highs in the 40s and 50s. Reinforcing cold
air will build in for Tuesday/Wednesday with highs in the 30s and
40s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 533 AM CST Thu Nov 24 2016
A mix of IFR and MVFR conditions continue at all 3 TAF sites, and
will likely continue for a good part of this forecast period.
Bases will again increase to MVFR through the day, but should
remain below VFR at all 3 sites. A weak storm system may bring
some rain to KOMA/KOFK this afternoon to early evening, but these
are expected to be very light. As winds become northwest tonight
behind the system we will likely start to clear out the stratus at
KOFK/KLNK late in the period, but will keep KOMA MVFR through 12Z
Friday.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Zapotocny
LONG TERM...Zapotocny
AVIATION...Boustead
Area Forecast Discussion
National Weather Service Paducah KY
918 AM CST Thu Nov 24 2016
.UPDATE...
Issued at 918 AM CST Thu Nov 24 2016
Aviation update.
UPDATE Issued at 852 AM CST Thu Nov 24 2016
After looking at the new data from the NAM/RAP, and given
satellite trends, will make significant changes to the cloud
forecast through tonight. Forecast soundings show moisture
trapped below a strong inversion just above the top of the cloud
layer, with rather weak flow unable to mix the below inversion
layer enough to warrant a decrease in the low cloud cover. This
may also affect temperatures. The HRRR data shows most areas
unable to reach 50 today. The other guidance has yet to catch on
to this possibility. Will trend lower/cooler, but not as low as
the HRRR just yet.
CN
&&
.SHORT TERM...(Today through Saturday night)
Issued at 229 AM CST Thu Nov 24 2016
In general, clouds/drizzle/fog are hanging tough, and slower to
clear/erode, than modeled/forecast. So we have trended the near
term for a little slower on the rate of dispersion, which leads in
turn to a little (overall) cloudier forecast, as the next (fast
moving/still dry passage) system incoming for Black Friday spills
clouds in even as we briefly clear from the system prior.
That is the primary change in the near term forecast, which
otherwise still shows High pressure building into/across the
lower Ohio river valley, a fast moving/dry cold frontal passage
Friday, and then surface High pressure again building into/across
the lower Ohio valley into the weekend. The forecast remains dry
with seasonal temps primarily in the 50s/30s for highs/lows each
day.
.LONG TERM...(Sunday through Wednesday)
Issued at 229 AM CST Thu Nov 24 2016
The medium range models and their ensembles are now in better
agreement than in previous days, so the rain event early next week
can be forecast with greater confidence.
An expansive mid/upper ridge will be in place across the CONUS at
the beginning of the extended period, with the center of high
surface pressure over the PAH forecast area. This high will drift
off toward the Carolinas throughout the weekend.
Southwesterly return flow (850 mb) of about 50 knots should get
established Sunday night in the PAH forecast area ahead of an
expansive mid level longwave trof which is progged to become more
and more dominant across the CONUS with time, setting up a prolonged
southwesterly flow aloft over the Midwest. As the parent stacked low
moves toward MN early Monday, the low level jet will combine with
fast winds aloft to create large scale lift over our area, enhanced
by difficult-to-time impulses in the flow aloft, which may or may
not be accompanied by a surface waves.
This should result in rain showers Sunday night for us, starting in
southeastern MO/southern IL and gradually moving eastward, though
the southeastern Pennyrile region may escape substantial rainfall
through much of Monday. There may be just enough instability for a
little lightning Monday through Monday evening, mainly in
southeastern MO/Purchase area of KY/southernmost IL.
As one likely impulse moves through, it appears the window for
highest PoPs and QPF for the region overall will be Monday afternoon
through Tuesday morning. The sustained pattern of southwesterly flow
will be conducive to two to three inches of total rainfall being
probable, with higher amounts possible. This could cause some minor
flooding issues. Pcpn is expected to taper off from west to east
late Tuesday. Some model indications are that additional impulses in
the cyclonic flow could generate more rain Wednesday, but the
forecast PoPs will be kept under 15% for now.
In this pattern, temps will continue to be mild, especially
Monday/Tuesday, when the lows will be above freezing and highs in
the upper 50s/lower 60s.
&&
.AVIATION...
Issued at 918 AM CST Thu Nov 24 2016
Significant changes to the cloud forecast, which will affect all
terminals. Model projections show little to no chance we will
erode the low cloud cover. Thus, kept MVFR cigs in for the entire
duration of the forecast. Light NNW winds today will become
variable by dark, near calm at times. VSBYS should generally be
VFR, though some brief MVFR vsbys cannot be ruled out entirely.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
Area Forecast Discussion
National Weather Service Portland Oregon
238 AM PST Thu Nov 24 2016
.SYNOPSIS...A strong frontal boundary will move into Southwest
Washington and far Northwest Oregon this morning then become nearly
stationary. A secondary low pressure area develops offshore along the
front this afternoon, reaching the North Washington coast Thursday
night. The frontal boundary weakens late Thursday night and Friday
morning with the main energy over Southwest Oregon. A cold upper
trough settles over the forecast area this weekend. The general
progressive pattern continues next week.
&&
.SHORT TERM...Today through Saturday...Complicated weather pattern
shaping up during the next 36-48 hours with below normal confidence
in some details due to continued model differences. Water vapor
satellite imagery early this morning shows an impressive shortwave
trough encompassing much of the Gulf of Alaska. More impressive is
the convective activity over the coastal waters and the South
Washington and North Oregon coast associated with a frontal boundary.
KLGX Doppler radar shows the impressive line extending from near
Raymond to about KTMK. Lightning detection showed up to 125 cloud to
ground strikes within this line from 08Z to 09Z.
A strong jet on the backside of the trough is beginning to result in
the shortwave trough digging. This will result in the approaching
front to become more oriented from southwest to northeast as it drops
southeastward across the area late tonight and Thursday. Biggest
forecast question today will be QPF. Models differ on location of the
QPF core within the baroclinic zone. The 06Z NAM has the front
stalling across SW Washington and far NW Oregon this afternoon, while
the ECMWF is a little more southeast, somewhat similar to the 00Z
GFS. However, the 06Z GFS is trending toward the 06Z NAM solution.
Another forecast issue will be coastal wind. 06Z NAM does show 70 kt
850 mb and 900 mb wind speeds off the North-Central Oregon coast 15Z
today. Wind speeds diminish from north to south later this morning as
the front sags southeast. Again, the main forecast challenge will be
the actual frontal location by early afternoon. There is also a high
wind watch valid late this afternoon through this evening. Overall
confidence in this event is less than optimum. 06Z NAM and GFS have
come more into line showing a secondary low pressure area developing
out near 140W early this morning and then continuing to deepen today
as it heads toward the Washington coast. The ECMWF does not have near
the surface reflection as the NAM or GFS. The NAM indicates 65-75 kt
850 mb and 900 mb wind speeds along the Central Oregon coast early
this evening. With the current warning in place, will punt to the day
shift on the high wind watch.
Snow levels continue to hover around 3500-4000 feet in the Cascades
per surface observations. It should be noted that temperatures have
fallen across the upper Hood River valley and we could see
precipitation begin to mix with snow above 2000-2500 feet this
morning. The NAM & WRF-ARW wet bulb zero heights support this idea as
cold air banks up against the Cascades. Do not foresee major
accumulations at these elevations, but still something worth
monitoring.
Models continue to vary considerably on what becomes of the
aforementioned baroclinic boundary, which leads to difficult QPF
forecast challenges. The GEM, EC & WRF-ARW models hold the heaviest
QPF over the Nehalem, Wilson, Nestucca and Siletz River Basins today
while the latest GFS & HRRR runs suggest the front will likely drop
southward this morning and end up over the Alsea and Siuslaw River
drainages by midday. The GFS & HRRR runs would be less likely to
produce river flooding as the heaviest rainfall would likely not sit
over any given drainage too long. The 06Z GFS has the heaviest rain
this afternoon over the North Oregon coast basins, then slowly shifts
the focus south late this afternoon and tonight. By Friday morning
the front has weakened with the primary dynamics over far SW Oregon
and NW California. But, the front never goes completely away. The
GFS, and to a certain extent the ECMWF, lift the frontal remains
north Fri evening and Fri night as a colder upper level trough pushes
toward the coast.
Snow levels will vary quite a bit across the Cascades today and
tonight. Cold air will likely be stubborn to scour out across the
south Washington Cascades especially near Mt Adams where 10-20 inches
of snow appear likely above 3500` and somewhere between 15-30 inches
above 4500`. Warm air streaming northeastward ahead of the front
should result in snow levels rising to around 4500 feet this
afternoon across the Oregon Cascades. This process will be slowest to
occur near Mt Hood so the current Winter Wx Advisory looks on track.
The good news is that this should bring a period of improved travel
conditions for those traveling across the Cascade passes today.
The cold upper trough Saturday will keep snow levels below the
passes. QPF will not be all that impressive, but snow will continue
to accumulate above the passes. Weishaar
.LONG TERM...(Saturday night through Wednesday)...No Changes...
Previous Discussion from Wednesday afternoon follows...The active
weather pattern looks to continue through much of the long term
forecast as a series of storm systems move across the Pac NW. Models
continue to show an upper level trough moving across the forecast
area Saturday night and Sunday which will maintain showers over the
region. Snow levels look to lower to around 2500 ft on Sunday, with
an additional 3 to 6 inches possible at the Cascade passes. If you
are planning on traveling over the Cascades, prepare for hazardous
road conditions.
Models then show a weak upper level shortwave dropping southeastward
Sunday night and Monday. This system looks to bring another round of
rain to the area late Sunday/early Monday, with cool northwesterly
flow keeping showers going on Monday. High pressure looks to build
across the area Monday night and Tuesday bring with it a period of
quieter weather and raising snow levels to around 4500 ft. However,
this bring will be short as models show another upper level trough
dropping south out of the Gulf of Alaska Tuesday night and Wednesday
which could bring another round of heavy rain and Cascade snow, with
locally windy conditions. /64
&&
.AVIATION...Primarily VFR early this morning with occasional MVFR
CIGS and VIS at the coast. This should trend toward more MVFR
conditions this morning at the coast. A band of thunderstorms
stretching from near KAST southwest over the coastal waters. If
current trends continue most of the coastal areas will see some
thunderstorms through about 15Z as the band shifts east. Southerly
wind gusting 30 to 40 kt right along the coast will ease later
this morning as a cold front moves ashore. South winds appear to
increase again with gusts 30 to 40 knots Thursday evening but
there is significant model uncertainty regarding the track of a
potential surface low and even it`s possible existence versus on
open surface trough. 06Z model runs are in better agreement but
still have significant differences in the details.
Inland areas remain generally VFR into this evening, but areas
from KSLE northward have better chances for MVFR CIGS and VIS
after 21Z Thu as heavier precipitation leans further inland.
KPDX AND APPROACHES...VFR prevailing through about 21Z Thu
then a good chance for MVFR CIGS in the 2000 to 3000 ft range to
occasionally affect the TAF sites. MVFR conditions may continue
through tonight into early Fri.
&&
.MARINE...A band of thunderstorms extending southwest from near
Astoria will continue to slide east as a cold front pushes toward
the coast. The cold front may be further back from the convection
but valuable information from buoy 46029 shows pressure rises and
a slight windshift and decrease in wind. Hires wind models are
fairly close to the observation and this will push the front
through Astoria around 4 am, then slide down the coast to Florence
by 10 am if not a couple of hours earlier. Seas appear to have hit
its peak around 20 ft around 1 am for the northern waters, but the
central Oregon coastal waters may still a bump to 22 ft early this
morning. Seas will gradually subside this morning but remain above
15 feet through Friday with a bump back up to near 20 ft this
evening with the next system.
Models have not done well with this system for Thu evening. The
track and strength of this second system keeps changing in small
but impactful ways, leading to more uncertainty. The 06Z models
are in slightly better agreement but confidence in the forecast is
still not very high. But a decision has to be made so will
convert the Storm Watch to a Gale Warning starting late this
afternoon through late evening. Feel fairly confident that the
waters south of Cascade Head will see gales, and possibly a short
period of near storm force gusts early this evening. North of
Cascade Head confidence is lower as model solutions vary from
Small Craft Advisory to Gale force winds.
Friday things start to calm down, with winds and seas coming back
down. Still think we will see small craft advisory winds through
most of the day on Friday, though winds should drop below 20 kt
by Friday evening. Seas should drop back down into the mid-teens
by Friday evening as well. Weaker fronts move across the waters
over the weekend, but generally seas expected to drop to around 9 ft
by Saturday night or Sunday, and winds stay fairly benign for this
time of year. /mh
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 4 AM PST Friday for Northern
Oregon Cascades.
High Wind Warning until 10 AM PST this morning for Central
Oregon Coast-North Oregon Coast.
Flood Watch from 10 AM PST this morning through Friday evening
for Central Coast Range of Western Oregon-Central Oregon
Coast-Central Willamette Valley-Coast Range of Northwest
Oregon-Greater Portland Metro Area-North Oregon Coast-
South Willamette Valley.
High Wind Watch from this afternoon through this evening for
Central Oregon Coast-North Oregon Coast.
WA...Winter Storm Warning until 4 AM PST Friday for South Washington
Cascades.
Flood Watch from 10 AM PST this morning through Friday evening
for South Washington Coast.
High Wind Watch from this afternoon through this evening for
South Washington Coast.
PZ...Gale Warning until 10 AM PST this morning for Coastal Waters
from Cape Shoalwater WA to Florence OR out 60 nm.
Gale Warning from 1 PM this afternoon to midnight PST tonight
for Coastal Waters from Cape Shoalwater WA to Florence OR
out 60 nm.
Small Craft Advisory for Rough Columbia River Bar until 4 PM
PST this afternoon.
&&
$$
Interact with us via social media:
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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. The area is
commonly referred to as the forecast area.
Area Forecast Discussion
National Weather Service Tulsa OK
545 AM CST Thu Nov 24 2016
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
IFR ceilings across nwrn AR sites will become VFR by late morning as
cloud deck erodes from west to east after sunrise. Variable
restricted flight conditions in fog/freezing fog over other sites
will also improve by late morning. All sites should be VFR with SCT-
BKN high clouds after 18z and wind becoming south/southeast. A weak
cold front will move through nern OK sites around 03z and through
MLC/FSM after 06z. WX NIL with the front.
&&
.PREV DISCUSSION... /Issued 337 AM CST Thu Nov 24 2016/
DISCUSSION...
Fog potential through mid to late morning is the primary forecast
concern. So far early this morning, any fog has been very patchy
and also very short lived at any one site. Both the experimental
and operational HRRR indicate this changing prior to sunrise
across portions of eastern Oklahoma and into the Arkansas River
Valley, in the cleared area on the western edge of the surface
ridge. Confidence is not high enough at this point to issue a
Dense Fog Advisory but we are prepared to issue one if
observations begin to support it. In addition to the dense fog
potential, a couple of sites have briefly reported freezing fog,
and as such, will include a patchy mention of freezing fog
generally from Claremore to Tahlequah to Sallisaw.
Southerly winds will return today as the surface ridge pushes to
the east, leading to above normal temperatures today. A fairly
fast moving, dry cold front will push through the region tonight,
with a brief decrease in temperatures following on Friday. Saturday
will be largely quiet with slightly warmer temperatures.
The next big weather maker will begin to affect the region Sunday
and into the early part of next week. Flow in advance of a large
trough over the western half of the country will lead to
increasing deep layer moisture and a resulting increase in shower
and thunderstorm potential. While activity should generally remain
scattered across the area into Sunday evening, better chances,
with some locally heavy rain potential, should arrive with a cold
front early Monday morning and into the day. Southeast Oklahoma
and into western Arkansas look to have the best shower and
thunderstorm potential during this time frame. The medium range
models differ somewhat with the handling of the system after
Monday, with the GFS lingering the front across the southeastern
half of the area, leading to rain chances into Monday night and
early Tuesday, whereas the ECMWF is more progressive with this
feature.
Much cooler temperatures and dry conditions will prevail toward
the middle of next week on the heels of the departing front.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 66 38 60 33 / 0 0 0 0
FSM 65 39 61 33 / 0 0 0 0
MLC 66 40 61 33 / 0 0 0 0
BVO 64 35 59 26 / 0 0 0 0
FYV 62 34 57 25 / 0 0 0 0
BYV 59 38 56 31 / 0 0 0 0
MKO 64 37 58 31 / 0 0 0 0
MIO 60 35 55 30 / 0 0 0 0
F10 65 38 59 33 / 0 0 0 0
HHW 66 41 62 35 / 0 0 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
LONG TERM....22
AVIATION...69
Area Forecast Discussion
National Weather Service Lincoln IL
159 PM CST Thu Nov 24 2016
.SHORT TERM...(This evening through Friday)
ISSUED AT 159 PM CST Thu Nov 24 2016
Expansive stratocumulus shield has started to erode over central and
western Missouri this afternoon. With the ridge overhead at the
moment, there are some doubts that this clearing will make it all
the way over here, as LAPS soundings still show a decent inversion
around 900 mb and RAP 925 mb humidity plots are pretty solid through
the night. So, will maintain the cloudy forecast overnight, followed
by some slow clearing on Friday once the upper wave currently over
the Dakotas passes by. With a bit of sunshine, temperatures should
get a little warmer on Friday, mainly mid to upper 40s with some 50
degree readings over the far southwest and southeast parts of the
CWA.
&&
.LONG TERM...(Friday night through Thursday)
ISSUED AT 159 PM CST Thu Nov 24 2016
Dry weather is expected the first part of the weekend as a
surface high pressure ridge moves across the area. As this high
pressure moves east into the southeastern US, a strong weather
system developing in the western plains will move out into the
plains and move northeast into the northern plains. The end of a
warm front should lift across a portion of central IL Sunday
afternoon and could bring showers to the western parts of the CWA.
As the main low pressure area lifts into the northern plains, warm
moist air will stream northward into the area the latter part of the
weekend and into the beginning of next week. This will cause
occasional showers across the area beginning Sunday night. There
could be a brief break in the precip Monday morning in the wake of
the first wave, but with models differing on how fast to bring the
secondary system into the area, will keep chance pops for Mon
morning. By Monday afternoon, the secondary system will lift out the
plains and bring heavier rain and rain showers to the most of the
CWA Monday afternoon through Monday night. Heavy rainfall will be
possible with this secondary wave, with around an inch possible in
southeast Illinois Mon afternoon through Mon evening. Moderate
rainfall will be possible north of this area over most of central
IL, with rainfall amounts exceeding over one half inch. Rain showers
will remain possible through Tuesday as the surface system pulls
away and the upper level system slowly moves northeast toward
Canada. Beyond this system, the ECMWF and GFS differ on if the area
will be dry or if there will be more showers somewhere in the area.
The ECMWF is showing more showers for the southeast Wed night, while
the GFS is dry. For now, will keep dry forecast since that is what
the ECMWF showed previously.
Temps will become unseasonably warm for the weekend and into the
beginning of next week as the main surface system stays to the west
and warm air is advected into the area. High temps are expected to
reach into the upper 50s to near 60 for Mon and Tue. Then temps will
drop back down to more seasonable levels for Wed and Thur.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1116 AM CST Thu Nov 24 2016
Expansive MVFR stratocumulus deck will continue much of the
forecast period. Some thin spots trying to form across Missouri,
but inversion will remain strong much of the time and currently do
not think any significant breaks in the clouds will occur until
Friday morning. Ceilings are very slowly rising, but VFR
conditions are not expected until mid to late morning on Friday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Geelhart
LONG TERM...Auten
AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Saint Louis MO
301 PM CST Thu Nov 24 2016
.SHORT TERM... (Through Late Friday Afternoon)
Issued at 258 PM CST Thu Nov 24 2016
Satellite imagery late this afternoon is showing that clouds are
eroding on the back side of the surface ridge across central
Missouri. This trend will likely continue to at least just west of
the Mississippi River before sunset when mixing ceases for the day.
Then RAP soundings are showing the low level profiles moistening
back up beneath 850mb overnight. This is part due to the area of low
clouds currently over Nebraska and northern Kansas ahead of a upper
trough moving across the northern Plains. This trough will move
across the Midwest bringing the moisture with it. Will go with
mostly cloudy to cloudy skies everywhere overnight before skies
clear out on Friday as drier air advects in from the northwest.
Should not be much drop in temperatures tonight with clouds holding
in place. Went warmer than MOS guidance in most locations. Clouds
will break out tomorrow morning helping highs climb to near GFS
MOS and SREF mean highs.
Gosselin
.LONG TERM... (Friday Night through Next Thursday)
Issued at 258 PM CST Thu Nov 24 2016
(Friday Night - Saturday Night)
An area of high pressure at the sfc will slide eastward from the
south-central Plains to near the confluence of the Ohio and
Mississippi Rivers by Saturday morning. This area of high pressure
will be accompanied by light winds and a clear sky...promoting a
good radiational cooling setup. Lows are expected to range from the
mid 20s to near freezing with the coldest conditions across the
eastern Ozarks. Favored cooler MET guidance for lows Friday
night...and even went a few degrees cooler than that for favored
terrain where model guidance has had a warm bias under similar
circumstances this fall.
As sfc high continues to slide predominantly eastward...southerly
return flow should be in full earnest by Saturday afternoon.
Temperatures should be 5+ degrees warmer on Saturday compared to
what is forecast for tomorrow. Look for highs in the 50s which is
back above normal for late November.
Lows on Saturday night will also be quite a bit warmer than the
previous night...mainly due to southerly sfc winds staying up around
5 knots all night long. Lows back above normal...and above the
freezing mark...are forecast areawide.
(Sunday - Next Thursday)
More active weather pattern will take shape for the end of the
weekend and into the next work week. Mid-Mississippi Valley will be
beneath southwest flow aloft with at least a couple of impulses
ejecting out of the longwave trough centered near the lee of the
Rockies. Two distinct rounds of rainfall are expected...one on
Sunday night with the highest chances across northern sections of
the CWFA...and the other Monday afternoon/night mainly for the
southeastern half of the CWA. Nothing that looks overly concerning
this far out in terms of hazardous weather. In fact...most parts of
the CWA have been running below to much below normal in the rainfall
department since the start of autumn. Therefore...a round or two of
widespread rainfall would actually be welcome from a hydrological
perspective...particularly for portions of southeast Missouri.
Temperatures will start off the period above normal and stay that
way through Tuesday. Temperatures are forecast to drop back to near
normal for Wednesday and next Thursday behind the second wave of
rainfall.
Gosselin
&&
.AVIATION... (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1125 AM CST Thu Nov 24 2016
MVFR clouds are expected to remain at all of the terminals through
at least mid morning on Friday as low level moisture remains
trapped in the lower atmosphere. High pressure moving across the
area will cause winds to be light and variable.
SPECIFICS FOR KSTL: MVFR clouds are expected through at least mid
morning on Friday with light and variable winds.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Morristown TN
237 PM EST Thu Nov 24 2016
.SHORT TERM (This Afternoon through Friday)...
Current water vapor imagery and RAP upper air analysis indicates a
shortwave ridge stretching across the Southern Appalachians
northwards into the Great Lakes. A trough is present both to the
east and west of this ridge with one across the Northeastern U.S.
and the other moving across the Rocky Mountains into the Central
Plains. At the surface, a surface boundary is located along the
Cumberland Plateau. This boundary has slowed since the ridge has
build into the region. Overall, the boundary is not very strong
with little to no cold air advection behind the boundary with
nothing more than shift to northwesterly winds. Expect mostly
cloudy skies will continue throughout the afternoon with plenty of
low level moisture around the surface boundary. The moisture is
only around 100mb deep and do not expect any precipitation across
the area this afternoon/evening. Smoke continues to be an issue
across the area but conditions have improved a great deal since
yesterday. Winds are currently in the 5- 10 mph at most
observations sites and this has helped disperse the smoke. However,
will continue with smoke in the forecast through the remainder of
the afternoon.
Patchy fog will become an issue tonight with low level moisture
remaining elevated around the surface boundary. Dewpoints are
currently in the low to mid 50s and expect low dewpoint depressions
overnight. Low level winds will also weaken as the boundary layer
begins to decouple tonight. Due to this, expect patchy fog will be
possible tonight across all of the forecast area. The smoke from the
recent wildfires will also act to decrease the visibilities as
well.
The surface boundary should push through the forecast area late
tonight into early tomorrow morning as an upper level trough moves
across the Central Plains into the Great Lakes. Could see a few
light showers/drizzle across SW VA as the boundary pushes through
with some weak low level convergence. As mentioned, the cold air
advection with the system is weak and highs will still top out in
the upper 50s to mid 60s.
.LONG TERM (Friday night through Thursday)...
High pressure builds into the region in the wake of the frontal
passage. Although a deeper trough digs over the northern Ohio
Valley dry conditions will persist. The models do indicate a more
promising trough digging over the southern Plains by Tuesday.
Differences in timing exist and with the deep amplitude of the
trough expected...will trend toward the slower solution. This will
bring the better chances of rain to the region on Tuesday afternoon
(thunder possible) and Tuesday night. This area sure could use the
precipitation! Nothing to get excited about but colder air on the
backside of this system could produce some areas of snow showers
limited to NE TN and SW VA for a few hours Thursday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 47 65 38 61 / 10 0 0 0
Knoxville McGhee Tyson Airport, TN 47 63 34 57 / 10 0 0 0
Oak Ridge, TN 46 63 36 58 / 10 0 0 0
Tri Cities Airport, TN 43 60 33 52 / 10 20 10 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&
$$
MA/AC
Area Forecast Discussion
National Weather Service Paducah KY
245 PM CST Thu Nov 24 2016
.SHORT TERM...(Tonight through Saturday night)
Issued at 245 PM CST Thu Nov 24 2016
Very difficult cloud forecast for the next 12-24 hours. The NAM
and RAP models show much greater moisture 950-925mb through Friday
while the GFS/ECMWF show a decrease. Satellite trends show
clearing corresponds fairly well with a 15kt westerly 850mb flow
serving to work drying in from above into a shallow moist layer.
We are only a couple of hours from sunset. So, this clearing may
slow given the weak flow. Or, there could be some low cloud
redevelopment where it clears (fog?). Will have to monitor
closely. Updates can be expected to clouds. If the clouds hold,
most areas should remain slightly above guidance lows.
Overall there should be a decrease in clouds Friday through Friday
night. Dry weather on through Saturday with high pressure in
control through the duration. Went slightly below guidance for
Friday`s highs given lingering cloud potential. Again lower
confidence call here. Chilly Friday night and Saturday night.
Stayed near MOS for highs Saturday.
.LONG TERM...(Sunday through Thursday)
Issued at 245 PM CST Thu Nov 24 2016
Ridging aloft and retreating high pressure during the latter half of
the weekend over the Midwest will give way to increasing
southwesterlies through a deep layer Sunday night. This should
result in a "comma head" of light pcpn Sunday night to the southeast
of a deepening stacked low that will be headed for the Dakotas or MN.
For Monday afternoon and night, a lobe of energy in the expansive
mid level longwave over 2/3rds of the CONUS is progged by the med
range models to enhance lift and result in more robust rainfall
across most of the PAH forecast area. This should be when the most
QPF occurs. At this time, lightning potential is very low, and was
left out of the extended forecast for now. Total QPF is now
generally 1 to 2 inches, with higher amounts possible (subject to
change).
The weather picture gets a bit more murky after that, since the med
range models do begin to differ in the finer details, though they
are in somewhat better agreement in the large scale pattern details.
An additional difficult-to-time impulse or two in the parent
longwave may or may not follow, causing rain showers to possibly
linger well into Tuesday, and perhaps Tuesday night. At this time,
Wednesday and Thursday is forecast to be dry, though the 12Z ECMWF
run suggests another impulse in the southwesterly flow aloft could
trigger another batch of showers.
Sunshine may return for a while on Tuesday afternoon, resulting in
temps possibly reaching the middle 60s in southwestern IN/western
KY. There should be a cooldown in the latter half of the week as mid
level heights fall and deep layer winds turn more northwesterly.
&&
.AVIATION...
Issued at 245 PM CST Thu Nov 24 2016
Clouds will continue to be the focus of the forecast through
Friday morning. Clearing has worked across central and southern
MO. How far east this will make it remains to be seen, and a tough
call. We are closing in on sunset in a couple of hours, and the
overall flow remains very weak. Will continue to keep cigs at the
terminals down in the MVFR category until we see a change. Later
shifts can update accordingly. Winds will be light.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$