Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/21/16
Area Forecast Discussion
National Weather Service Albany NY
1034 PM EDT Thu Oct 20 2016
.SYNOPSIS...
A large slow moving storm system will impact the region through
the weekend bringing much needed rainfall to the area. Ahead of
the storm conditions will be mild, however strong and gusty winds
on the back side of the storm Saturday and Sunday will usher in
a much colder airmass. Some snow is possible across the higher
terrain of the southern Adirondacks and southern Green Mountains
Saturday night into Sunday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 1034 PM EDT...A warm front is draped across southern parts
of the region. Parts of the mid-Hudson Valley and NW CT are seeing
temps in the 60s with a S-SE wind, while the remainder of the area
is in the 50s with calm or light NE winds.
KENX and regional mosaic radar shows dry conditions over the
majority of the area. However, a slow moving band of rain is
located over central and western NY. This band is in place thanks
to favorable jet dynamics along with a slow-moving frontal zone.
This rain band is starting to reach into the western Adirondacks,
although the heaviest rainfall is still located west of the area
over central NY. The 00Z KALY sounding shows a PWAT of 1.09 inches
and KBUF showed 1.30 inches, so definitely some decent moisture
in place for mid-October. As a result, there have been some
locally heavy downpours with this rainfall and even some embedded
thunder as well, especially across the southern tier of NY and
into central PA.
Overnight, the warm front will continue to lift northward across
the area as the upper level trough to our west continues to
deepens tonight and move eastward. The associated surface low will
strengthen over the Ohio Valley and head towards western
NY/western PA by late tonight.
The band of rain over central NY will try to make some eastern
progress, but it will occur rather slowly. The 3km HRRR suggests
that the very heaviest rainfall remains west of our area,
although some light to moderate rain will occur across the far
western Mohawk Valley and western Adirondacks. Based on model
instability forecast, will not include thunder in our area, but
will continue to monitor upstream trends. The far northwestern
corner of our area in northern Herkimer County could see one to
two inches of rainfall overnight, but there is a tight gradient
between the heavier rainfall and seeing very little rainfall just
east of there due to the slow movement of the heavy rainfall
band.
Further south and east, can not rule out chances for showers
across the rest of the forecast, although most of the region will
remain rain-free, but still be cloudy, damp and misty at times.
Lows mainly will be in the 50s, which is similar to what the
normal highs are for mid October. Temps overnight will hold steady
or slowly rise as the warm front lifts through the area.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Much needed rainfall through Saturday night.
The upper trough will become negatively tilted and an upper level
low will form with a vertically stacked system developing Friday
night into early Saturday. The broad area of low pressure in the
tropical will be drawn toward the east coast and eventually being
absorbed/merged into the developing stacked system. The National
Hurricane Center states it could develop into a tropical system
before it gets incorporates into the large synoptic scale system.
Please refer to products issued by the National Hurricane Center
for details and forecasts. Either way it brings tropical moistures
into the system.
Chances for rainfall will increase from the northwest and southeast
Friday especially during the afternoon and as the storm develops and
its cold front moves across the region from the west and the tropical
moisture is drawn in off the coast. It will be very mild ahead of the
system with highs mainly in the 60s into the 70s.
With the passage of the cold front and rapidly deepening of the
system a much colder airmass will be ushered in a strong, brisk
and gusty winds. The surface low is forecast to go from 996 mb
00Z Sat to 979 mb 00Z Sun. A Wind Advisory may be needed, at this
time have wind gusts of 35 to 45 mph in the forecast for Saturday
into saturday night. Guidance has winds in the 40s at 30 feet above
ground level especially across the higher terrain. Will keep mention
in the Hazardous Weather Outlook.
As colder air is ushered in rain should change to snow across the
higher terrain of the southern Adirondacks and southern Green
Mountains with some snowfall accumulations possible Saturday night.
Will keep mention in the Hazardous Weather Outlook.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Deep and mature cyclone over Quebec will slowly drift northeast on
Sunday, and begin to weaken and fill. Behind this storm, the
combination of a lingering strong pressure gradient and good daytime
mixing will allow for some gusty winds on Sunday. W-NW winds will
gust 25-35 mph at times, especially over the higher elevations.
There may be a few lingering rain or snow showers over the
Adirondacks and Southern Green Mountains, otherwise it should be dry
on Sunday with a mix of sun and clouds. The most amount of sun will
be for valley areas, where some downsloping will aid in allowing for
more sunshine. Temps look to generally range between the mid 40s and
mid 50s across the area.
Within the quick northwest flow, another fast moving storm system
will approach the area for Sunday night into Monday. With both
warming temps aloft and in the boundary layer, most of this precip
looks to be rain showers, with the best chance for seeing precip
north and west of Albany. Any areas that see precip look to be
fairly light, generally just a tenth of an inch or less. Lows on
Sunday night will be in the mid 30s to mid 40s and highs on Monday
will be in the 40s and 50s (although a few upper 30s are possible
for the Adirondacks).
The upper through will remain over the area for Tuesday, keeping the
cool weather in place. There still could be a lingering rain or
snow shower for northwestern parts of the region, but most areas
will stay dry with a partly cloudy sky. Temps look to only reach
the 40s across much of the region.
High pressure look to build across the area for Wednesday into
Thursday, keeping the dry weather in place. Temps will gradually
increase each day, but still look to remain below normal through the
mid-week period, with highs generally in the 40s to low 50s and lows
in the 20s and 30s.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Steady rainfall has ended and only a few light scattered rain
showers are expected overnight, as a warm front lifts northward
across the area. Light NE or calm winds will become S-SE by later
tonight at 5-10 kts as the warm front crosses the area by late
tonight. Although there won`t be much precip overnight, flying
conditions will generally be MVFR due to lingering low-level
moisture allowing for plenty of stratus clouds. This will be
especially true for areas already south of the warm front, such as
near KPSF/KPOU, where a persistent S-SE flow may even allow for
IFR stratus by later tonight.
IFR/MVFR conditions will continue into Friday morning. However, some
breaks in the clouds by late Friday morning into Friday afternoon
may allow for a brief return to VFR conditions. However, a more
concentrated area of rain showers look to return to the area by
late Friday afternoon into Friday evening as a cold front starts
to approach from the west. SE winds at 5-10 kts will continue
through the entire day on Friday.
Outlook...
Friday Night: High Operational Impact. Definite SHRA...RA.
Saturday: High Operational Impact. Breezy Likely SHRA.
Saturday Night: Moderate Operational Impact. Breezy Chance of SHRA.
Sunday: Low Operational Impact. Breezy NO SIG WX.
Sunday Night: Low Operational Impact. Slight Chance of SHRA.
Monday: Low Operational Impact. Slight Chance of SHRA.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX
&&
.FIRE WEATHER...
A large slow moving storm system will impact the region through
the weekend bringing much needed rainfall to the area. Ahead of
the storm conditions will be mild, however strong and gusty winds
on the back side of the storm Saturday and Sunday will usher in
a much colder airmass.
&&
.HYDROLOGY...
A large slow moving storm system will impact the region through
the weekend bringing much needed rainfall to the area. The highest
QPF totals of 2 to 3 inches for tonight through Saturday night
are expected across the western Adirondacks and western Mohawk
Valley with even higher totals to the west. The lowest QPF of a
quarter of an inch to an inch are expected across the mid Hudson
Valley. Expecting significantly within bank rises. Leaves clogging
drains could result in some minor urban flooding particularly in
poor drainage and low low lying areas.
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...IAA
NEAR TERM...IAA/Frugis
SHORT TERM...IAA
LONG TERM...Frugis
AVIATION...Frugis
FIRE WEATHER...IAA
HYDROLOGY...IAA
Area Forecast Discussion
National Weather Service Bismarck ND
941 PM CDT Thu Oct 20 2016
.UPDATE...
Issued at 930 PM CDT Thu Oct 20 2016
Only change for late-evening update was to increase cloud cover over
the James River Valley as low clouds are starting to try and
spread back to the north, in line with latest HRRR guidance.
Updates have been sent.
UPDATE Issued at 634 PM CDT Thu Oct 20 2016
Low clouds over the James River Valley continue to dissipate while
higher clouds push in over an upper level ridge to the west. Weak
wave noted in the ridge pushes over the area tonight which may be
able to squeeze out a few light showers over northern locations.
&&
.SHORT TERM...(This evening through Friday)
Issued at 217 PM CDT Thu Oct 20 2016
Tonight, low clouds will move into the region again as another
upper level wave moves across North Dakota. The majority of
locations should remain dry. However, scattered light rain is
possible across far northern North Dakota where the best upper
level support and lift will be located.
Otherwise, temperatures will fall into the 30s and southerly winds
will shift out of the northwest.
During the day Friday a cold front will swing through North
Dakota. Behind the front, cold air advection and a westerly mixing
wind component will likely produce a breezy day. Winds 15-20 mph
with gusts as high as 35 mph seem likely. Even though cold air
advection will be taking place, compressional warming, plenty of
sunshine and downsloping winds will boost temperatures into the
60s.
.LONG TERM...(Friday night through Thursday)
Issued at 217 PM CDT Thu Oct 20 2016
Another wave moves through on Saturday. This time the surface low
is a bit deeper and focused across North Dakota. However, moisture
will be limited and precipitation chances should be confined to
far northern North Dakota once again. The main impact with this
system will likely once again be winds. Windy conditions are
possible Saturday evening as the trough moves through. A nice
pressure rise of 6 mb/3hour combined with a westerly downsloping
component and steep lapse rates could produce winds around 30 to
40 mph. However, models differ on the timing of the trough and
pressure rises. Some models don`t move the pressure bubble through
until after dark, limiting mixing of stronger winds.
Otherwise, an upper level ridge moves into the Northern Plains.
This will likely keep the weather rather quiet and mild through
early next week. The ridge begins to break down by next week and
several waves may impact the region, bringing chances for
precipitation back to North Dakota.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 634 PM CDT Thu Oct 20 2016
Areas of MVFR cigs remain over the James River Valley though are
expected to gradually erode this evening. Otherwise...VFR
conditions are expected.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...JJS
Area Forecast Discussion
National Weather Service Burlington VT
1006 PM EDT Thu Oct 20 2016
.SYNOPSIS...
Strengthening surface low pressure system has started bringing widespread
rain to the North Country and will continue to do so through Sunday.
Occasionally heavy rainfall is expected, especially this evening into
early Friday, across the Saint Lawrence Valley and Northern Adirondacks.
As the front pushes east of the area by early next week a return
to drier weather and seasonably cooler temperatures is expected.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 1006 PM EDT Thursday...Overall forecast in good shape with
just the need to sharpen up the precipitation gradient across the
area with categorical precipitation chances over the Saint
Lawrence Valley of New York to chance over eastern Vermont as
precipitation moving more north than east.
Previous Discussion...
The 500mb trough continues to dig south and east over the central
USA. The rain has been slightly more widespread, mainly in the St
Lawrence Valley and Adirondacks but Western VT is also seeing
precip moving through rather quickly from the SW. The main
question remains how far north and east it will spread before the
deepening trough and surface low riding up the frontal boundary
causes area of rain to pivot north and west sometime on Friday.
The HRRR continues to have the best handle on the near term precip
for the St Lawrence Valley, have adjusted the PoPs and QPF
slightly to show the heightened band of precip making it`s way
into VT.
Strong low level deformation associated with front moves into St
Lawrence later this afternoon and into tonight, leading to
heavier rainfall for Nrn NY overnight, before weakening on
Friday. Another consideration for Friday is sub- tropical system
weakening as it heads north far off the Carolina coast, but
moisture looks to get absorbed or wrapped into the low affecting
the Northeast, and could result in resurgence of heavier precip
over eastern VT late Friday into Friday night, per the 00Z ECMWF.
This may be dependent on when the 500mb trough becomes more
neutral or negatively tilted late Friday.
Winds another concern as strong low level jet enters the region
this afternoon. Southerly jet of 40-55kts at 850mb stays over the
North Country through Friday. This will lead to strong winds
across the higher terrain. Best chances for strong winds to mix
into the valleys would be early Friday as the precip shield pivots
slightly NW, allowing for breaks in precip over VT. Have gusts up
to 15-25kts across most of the area on Friday, before the surface
low tracks over the area.
In summary, cloudy and wet pattern expected throughout the near
term with temperatures in the mid 50s to mid 60s today as we
remain in the warm sector. Tonight temperatures remain mild in the
mid 40s to upper 50s. Forecast max temperatures will be very tricky
on Friday as the surface low and associated front traverse across
the North Country. Timing of FROPA will dictate wind shift of NW-N
and colder air filtering in, especially through the valleys and
lower terrain.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 406 PM EDT Thursday...Forecast highlight of the period
continues to be unsettled conditions and our first mixed
precipitation event with the challenge being timing of heaviest
QPF and transition from liquid to frozen form. Deep mid/upper
level trough shifting out of the Great Lakes Friday night becomes
negatively tilted and eventually closes off over the North Country
by Saturday morning. Meanwhile at the surface, weak low pressure
moving northeast along the frontal wave interacts with a broad
area of low pressure currently northeast of the central Bahamas,
developing a robust surface low over VT/NH/ME. The result for
Friday night is that the best low level deformation remains across
northern New York with widespread rains continuing, while points
eastward will be affected by a mid-level dry slot with less QPF
expected.
As the surface low intensifies, the system becomes vertically
stacked as it shifts north to the vicinity of Quebec City by days
end Saturday. Low/mid level flow shifts to the northwest, but
strong low level cold air advection lags a bit compared to
previous model runs. This difference in timing amongst the latest
hi-res CAMs and global models presents some issues in regards to
ptype transition Saturday afternoon as conditions become favorable
for upslope precipitation to develop as the 700mb low sits just
north of the CWA. Currently I`ve offered a blended approach which
brings in colder air Saturday night with the transition from rain
to snow mainly occurring above 1500 feet with several inches of
snow likely at the highest summit peaks. At the surface below 1500
feet, a dusting to perhaps an inch is possible, with basically
nothing in the deeper Champlain and St. Lawrence Valleys.
Additionally as a strong low level jet of 30-40kts develops, winds
will be increasingly gusty Saturday afternoon and night, gusting
to 20-30 mph, mainly across northern New York.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 350 PM EDT Thursday...The long term pattern will feature a general
mid/upper level trof across the ne conus supporting below normal
temperatures and terrain focused precip. Upslope parameters still
look very favorable thru 18z Sunday with deep 850 to 500mb
moisture and strong northwest flow of 35 to 50 knots...enhancing
lift along the northern Dacks and western slopes. Additional qpf
amounts will be a tenth to two tenths with highest amounts from Mt
Mansfield to Jay Peak. Based on sounding profiles snow levels
should be near the bases at 12z around 1500 feet...but lifting
above 2000 feet before tapering off by 18z Sunday afternoon.
Expecting only a minor additional snow accumulation. Progged 850
mb temps between -3 to -5c support highs only in the 20s mountains
to mid/upper 40s warmer valleys.
Large scale pattern supports additional free refills of mountain
snow showers on Monday into Weds...as moisture and short wave energy
rotates around mid/upper level trof across eastern Canada. The
cyclonic flow through all levels will promote favorable upslope flow
with terrain focused precip. Have mentioned high chance pops for
mountains and slight chance elsewhere for Sunday Night into Weds.
Progged 850mb temps stay below 0c and actually get colder during the
early part of next week with values between -7c and -9c. Little too
early for detailed snowfall amounts and qpf values...but would
expect the mountains to stay white for through mid week. Eventually
mid/upper level trof lifts and zonal flow aloft develops with temps
returning closer to normal...for Thursday. Next system arrives on
Thursday night into Friday with additional chances for precip.
Overall temps are in the 20s to mid 30s mountains to mid 40s valleys
with lows mainly in the lower 20s mountains to lower 30s valleys.
&&
.AVIATION /02Z Friday THROUGH Tuesday/...
Through 00z Saturday...VFR conditions quickly giving way to
MVFR/IFR and even some LIFR during the overnight. Earlier showers
have moved out with a much larger rain shield moving into NY and
eventually spreading into western VT overnight.
it will stay ifr with rain at KMSS and scattered showers at KSLK Friday
but will give way to MVFR and some temporary dry air across
champlain valley and VT til afternoon then cold front slowly
progresses east with north winds/low cigs/drizzle/rain for mvfr-
ifr aft 18z.
Northeast winds 8-15 kts for KMSS through duration...light
variable/SE 5-10kts for rest of area overnight with possibly going
south at 10-15 kts for KBTV and KMPV between 12-16z Fri then going
north through afternoon.
Rather confident of prolonged period of mvfr-ifr and even lifr but
lower confidence on exact details/timing.
Outlook 00z Saturday through Monday...
00z Saturday through 00z Monday: A prolonged period of unsettled
conditions is expected with widespread MVFR/IFR in periods of
rain.
00z Monday through 00z Tuesday: A mix of VFR/MVFR...with VFR/IFR
possible in showers.
&&
.HYDROLOGY...
As of 350 PM EDT Thursday...A widespread and long duration
rainfall of 1 to 3 inches with amounts near 4 inches across the
St Lawrence Valley from tonight through Sunday. There will be
some breaks throughout the event, especially across portions of
Vermont. Given most of the region is in moderate to severe
drought...we are not anticipating any widespread hydro issues.
However...some minor urban and street flooding is possible
associated with the heavier rainfall rates on Friday with leaves
clogging storm drains. Otherwise...some modest rises in local
rivers and streams are likely this weekend...but no widespread
flooding is anticipated. The latest guidance from the NERFC brings
Ausable River near minor flood stage by Saturday Afternoon.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...KGM/MV
NEAR TERM...Evenson/MV
SHORT TERM...Lahiff
LONG TERM...Taber
AVIATION...MV/SLW
HYDROLOGY...Taber/KGM
Area Forecast Discussion
National Weather Service State College PA
1137 PM EDT Thu Oct 20 2016
.SYNOPSIS...
A storm system will move into Western Pennsylvania later today and
this evening. The associated cold front will move slowly across
the state tonight and Friday. Windy and much colder weather will
move in for the weekend with the first bout of lake effect and
upslope rain and snow showers Saturday into Saturday night.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Storms continue over the western CWA this evening with a few
warnings. HRRR shows limiting convecxtive activity east of I-99
as we move later in the evening.
Previous:
Satellite indicates the warm air has mixed down over all but the
far NW and NE. High temps are indeed a bit ahead of earlier
expectations with a cloudier sky.
The meso anal shows inverted trough poking up into NWRN Pa. This
connects to a wavy front over SWRN Pa and extends down into at
least one wave on the front over sern Ohio.
The NW looks to remain the focus for the best rains into the
evening today as the leading wave of low pressure ripples up into
western Pa by nightfall. As the associated upper trough deepens
and moves toward the NERN US, the wavy front will slow down with
the best rains concentrating along and behind the front, in almost
classic anafront fashion. The models show a strengthening upper
jet entrance region which will support strong deep layer
frontogenetic forcing moving slowly across the forecast area,
mainly tonight through the first half of Friday.
We are outlooked for a Slight Risk of severe storms which is not
unreasonable given the strong surge of moisture and expected
development of several hundred Joules of Cape by mid to late
afternoon as the front enters western Pa. Model depicted deep
layer shear will be similarly intensifying under the deepening
upper trough so the potential for damaging wind gusts will be
enhanced in any convection that can manage to organize. The best
chance of this would seem to be some sort of narrow cold frontal
rain band feature as the front strengthens and moves eastward. The
big question will be if the intensifying dynamic forcing can
overcome the increasing stability that will be occurring after
the sun goes down.
The front and area of rain will progress slowly eastward
overnight. Have chosen to not hoist a flood watch at this time
given the expected progressive nature of any kind of concentrated
convection that may form along the front. Can`t rule out some
smaller scale nuisance flooding as it is the the time of year that
fallen leaves can clog storm drains.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
There`s good consensus that the wavy front will have cleared at
least the western half of the forecast area by mid day to be east
of the entire forecast area by nightfall. Showers along the front
will transition onto a steady moderate to heavy soaking rain as
the front passes. The wind will shift to the NW and become gusty
along with steady or falling temperatures after the frontal
passage.
By late day we should see the rain finally starting to taper off
and become more showery.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
A major change in the weather pattern is expected to occur early
in the period which could yield the first taste of snow over parts
of Central Pennsylvania. An anomalous upper level trough will
close off and take on a negative tilt, with a deepening coastal
surface low tracking from southern New England north and west into
eastern Quebec. Strong cold advection on the backside of the low
along with 100-150m height falls and dynamic cooling within a
pivoting deformation axis could result in a rain/snow transition
Friday night into Saturday morning. The 20/12Z operational
EC/GFS/NAM/CMC generate a coating to 1 inch of snow over parts of
the Alleghenies and Laurel Highlands. Confidence in accumulation
is still low but odds would seem to be increasing. For now will
continue to mention rain/snow in the wx grids with no accums.
A seasonably cold and brisk northwest flow will grip the area
into the weekend with lake effect and orographic rain and snow
showers likely over the Northwest Mtns and Laurel Highlands on
Saturday. There is still a low risk for coating into Saturday
night with accums very hard to come by during the daylight hours
this early in the season. 25-35 mph wind gusts will add an
additional blustery chill to below normal temps.
GFS/EC/CMC all show a fast-moving low diving through the Great
Lakes and Northeast into early next week. There is better
agreement with this system embedded in the WNW flow aloft passing
to the north of the area with max POPs over the far northern
tier. This feature will reinforce the cold air aloft at least into
Tuesday before strong warm advection commences through midweek.
The models show a low near the Great Lakes by the end of the
period with some hints a at a cold air damming pattern at low
levels with high pressure retreating into New England. Overall
not much pcpn expected Mon-Wed.
Temperatures will be noticeably colder by the weekend with highs
in the low 40s to mid 50s on Saturday. Expect some moderation on
Sunday followed by a steady to cooling trend with readings
averaging near to below normal through next Wednesday.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
Minor adjustments made to 03Z TAFS.
Earlier discussion below.
Band of heavy showers and isolated thunderstorms will give way
to widespread showers and lower ceilings and visibilities later
tonight into Friday, as a cold front moves into the area.
Front will be slow to move east of the area before late Friday.
Outlook...
Sat...Scattered showers with restrictions NW. Brisk NW wind.
Sun...No sig wx.
Mon...Mainly VFR. MVFR with rain showers possible NW.
Tue...No Sig Wx.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Friday afternoon for PAZ004>006-010-
011-017-024-033-037.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte/Tyburski
SHORT TERM...La Corte
LONG TERM...Steinbugl
AVIATION...Martin
Area Forecast Discussion
National Weather Service Dodge City KS
1037 PM CDT Thu Oct 20 2016
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
Issued at 1032 PM CDT Thu Oct 20 2016
WV imagery indicates an upper level trough of low pressure moving
eastward across the Central Plains. Meanwhile, upper level ridging
is slowly building across the Desert Southwest. Near the surface,
high pressure is shifting slowly eastward across central Kansas.
&&
.SHORT TERM...(This evening through Friday)
Issued at 223 PM CDT Thu Oct 20 2016
Temperatures are the main issue for early Thursday morning. As
usual there is plenty of variance between he NAM/WRF and RAP-
HRRR solutions for early Thursday. Current thinking is a few
locations, especially the lower lying areas may touch freezing
mark briefly with most broad areas remaining in the mid 30s.
South winds should be steady and light and a frost advisory has
been posted across portion of the western forecast area. Much
warmer temperatures in the low to mid 70s are likely Thursday
afternoon with abundant insolation and gusty afternoon winds
nearing 30 knots at times from Liberal to Hays and eastward. The
Syracuse-Johnson areas will remain closer to the surface trough
through the day and the winds will remain light.
.LONG TERM...(Friday night through Thursday)
Issued at 223 PM CDT Thu Oct 20 2016
Highs will rise into the low 80s for the weekend as a strong
upper ridge develops across the mid section of the country. A
chance for a short wave that affects the central plains exists
around the middle of late part of next week, with large
uncertainty in numerical model placement of forcing mechanisms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 536 PM CDT Thu Oct 20 2016
VFR conditions are expected. As surface high pressure moves east,
a trough of low pressure will develop in the lee of the Rockies.
Light northeast winds become south after midnight, then increase
by mid to late morning to 15-28kt.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 39 73 43 81 / 0 0 0 0
GCK 36 75 41 82 / 0 0 0 0
EHA 38 77 42 84 / 0 0 0 0
LBL 36 75 40 83 / 0 0 0 0
HYS 38 70 42 79 / 0 0 0 0
P28 42 70 43 78 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 4 AM CDT /3 AM MDT/ to 8 AM CDT /7 AM MDT/
Friday for KSZ043-044-061>063-074-075.
&&
$$
SYNOPSIS...JJohnson
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Kruse
Area Forecast Discussion
National Weather Service Green Bay WI
1050 PM CDT THU OCT 20 2016
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Friday
Issued at 229 PM CDT Thu Oct 20 2016
The latest RAP analysis and satellite/radar imagery show a large
high pressure system stretching from central Canada southward to the
Great Plains. Upper troughing is moving over the western Great
Lakes, with cold advection continuing off of Lake Superior
contributing to a widespread cu field. Partial clearing is
occurring over western WI, and some of this clearing should push into
parts of central WI later this afternoon. With north flow
continuing tonight into Friday, cloud trends are the main forecast
concern.
Tonight...High pressure will be slowly moving east over the northern
Mississippi Valley. Northerly winds will continue on the eastern
flank of the surface high, and produce clouds off Lake Superior.
Some clouds will likely dissipate over parts of eastern and central
with the loss of daytime heating. But then may see a surge of clouds
southward over central WI late. Low temps should range through
the 30s with a few upper 20s possible in the cold spots of north-
central WI.
Friday...The surface ridge axis will move across the state. As
light winds back to the west through the day, should see early
morning clouds retreat northward some, but think thermal troughing
should still lead to a persistent cu field over northern and
northeast WI. So will go with partly to mostly cloudy skies for the
morning, then increasing sunshine for the afternoon over central WI.
Temps near todays readings.
.LONG TERM...Friday Night Through Thursday
Issued at 229 PM CDT Thu Oct 20 2016
Northwest flow will continue this weekend as a shortwave tracking
through the northern Great Lakes brings a small chance for showers
across the extreme northern cwa on Sunday afternoon. The models
seem to have converged on a solution in targeting this time period
which is coincident with peak heating, which when combined with
some added moisture from the lakes, should lead to better chances
than a nighttime window.
Other than the brief chance for rain across the north Sunday
afternoon, the weather should be relatively quiet through early
next week. The next chance for widespread rain does not arrive
until later next week when a more active pattern emerges for the
middle part of next week. The first chances arrive late Monday
night and into Tuesday as a warm front lifts north across the
western Great Lakes with a surface low tracking to our south on
Wednesday night. Although the models differ on the exact placement
of this low, the timing is in the ballpark. Also this run with the
low to the south the warm air does not seem to intrude as far
north with very little instability to speak of this far north.
Therefore will remove thunder from the forecast next week as the
best instability remains to the south. The main concern this run
is any further southward jog of this system to the south would
push the best rain chances further south, with smaller chances or
a dry forecast across the north in this scenario. At this point
will stay with the superblend and refine further in subsequent
forecasts.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1049 PM CDT Thu Oct 20 2016
Low cloud trends are the main aviation forecast issue. Other than
a break in the clouds which developed in north-central Wisconsin,
cloud deck has remained solid. Still think some thinning of the
clouds and breaks in the clouds could develop over those portions
of east-central/northeast Wisconsin where the northwest flow will
have a weak downslope component, but confidence in that is waning.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kurimski
AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
833 PM EDT Thu Oct 20 2016
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 329 PM EDT Thu Oct 20 2016
Areas of rain southeast of Grand Rapids will slowly end overnight.
Then as colder air spreads across the region, scattered lake effect
rain showers will develop along the lake shore late tonight into
Friday night. Otherwise the remainder of Friday and Saturday will
be dry and cooler with daytime highs only in the low to mid 50s.
Patchy frost will be possible late Friday night east of U.S. 131.
The beginning of next week continues to look mainly dry, with the
next chance of rain holding off until Wednesday and Thursday. After
highs around 60 on Sunday we will cool to daytime highs in the mid
to upper 40s Monday through Thursday.
&&
.UPDATE...
Issued at 833 PM EDT Thu Oct 20 2016
Seems the clouds have not shown much sign of clearing this evening
even through models like the HRRR and RAP plus the NAM12 seem to
like the idea. Typically north northeast to north surface winds
with cold advection in the lower levels favors this sort of night
time clearing of the clouds inland of the lake shore. Against that
is that we are well within the upper level cold pool and I have
noted over the years there are many cases where in that situation
the low clouds do not clear. So for now I delayed the low clouds
breaking up over our central CWA till well after midnight. If this
does not happen we will have to increase our forecast overnightlow
temperatures too.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 329 PM EDT Thu Oct 20 2016
Rain of the southeast counties will continue into this evening, then
gradually dwindle overnight. Cooler air slipping in will cause some
lake effect showers, mainly Friday afternoon into Friday night.
Low pressure over the Oh/WV borders will only move slowly NE,
causing the rain over the BTL, LAN, JXN areas to continue this
evening. But as the low continues to pull away this rain will slowly
let up after midnight.
Cooler air will spark lake effect overnight however with a NNE flow
much of this will stay over the lake, perhaps clipping the Points
region. Into Friday the flow becomes more NNW and inversion heights
will come up as a short wave approaches. Feel the best timeframe
for showers over SW MI lake shore will come Friday afternoon and
evening. Then inversion heights come back down once the short wave
is through by late Friday night.
Cloud cover should gradually erode into Saturday, or may even take
until Saturday night as a surface ridge moves in.
The short waves and NW upper flow that follows will keep us cool
with highs only in the low and mid 50s Fri and Sat.
.LONG TERM...(Sunday through Thursday)
Issued at 329 PM EDT Thu Oct 20 2016
The long term begins rather nice with temperatures that will
moderate back into the 60s on Sunday. Although some guidance
suggests that we could reach the mid to upper 60s, there are a
couple of limiting factors. As the upper ridge becomes more
pronounced over the plains, the result is west to northwest flow
with a shortwave quickly dropping through the Great Lakes Region
Sunday afternoon. Much of the precipitation will remain over
Northern Lower Michigan, but afternoon clouds could play a role in
keeping temperatures in the upper 50s north of Grand Rapids. Most
location along and south of I-96 are likely to see more sunshine to
round out the weekend.
Once the shortwave moves through, upper level ridging to the west
keeps Lower Michigan in northwest flow with cooler temperatures to
start next week. Surface high pressure builds in from the plains
resulting in quiet and dry conditions Monday through much of the day
Tuesday.
The pattern may become a bit more active by the middle of next week
with a few showers possible along a warm front late Tuesday
afternoon. As of now, higher chances remain west over Wisconsin.
Another system may become better organized over the plains with the
core of the upper jet pushing eastward. The upper trough deepens
over the Great Lakes Wednesday into Thursday with rain becoming
likely late Wednesday into Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 725 PM EDT Thu Oct 20 2016
VFR cigs will prevail at MKG through the next 24 hours, GRR will
become VFR with cigs by 03z and then maintain that through Friday
night. AZO and BTL are on the west edge of the light rain showers
from the system and have low MVFR cigs, by 06z cigs should become
none alternate MVFR and then VFR by 12z. JXN will take the longest
to become VFR but even there cigs should become VFR by mid morning
Friday. Most of the rain has ended over the area but a few light
showers are still possible till midnight. They should not be
enough to lower the visibility.
&&
.MARINE...
Issued at 329 PM EDT Thu Oct 20 2016
Will maintain the lake headlines as cold advection and brisk north
to northwest flow continues.
&&
.HYDROLOGY...
Issued at 330 PM EDT Thu Oct 20 2016
Rivers continue to improve through much of the area. Rainfall has
played out today mostly as expected. Small rises may occur along
small streams in affected locations. Otherwise, overall
precipitation chances are rather limited through the next 5 days.
Better chances for rain exist through the middle of next week. River
levels are expected to continue to fall. No flooding is forecast.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 8 PM EDT Friday for LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...JAM
AVIATION...WDM
HYDROLOGY...JAM
MARINE...JK
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1153 PM EDT Thu Oct 20 2016
.SYNOPSIS...
After a stretch of record warmth, a cold front will cross the area
tonight through Friday morning, increasing rain chances mainly over
the mountains. Drier and much cooler conditions will set up across
the area over the weekend. A dry "back door" front will push through
from the north on Monday with cool high pressure remaining in place
through the middle of next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1030 pm Thursday: Surface analysis shows that the front is
right on our doorstep, pretty much along the VA/KY border stretching
southwest through the southern part of the NC/TN border. Have made
another few minor tweaks to temperatures for the late evening
update, but the bigger adjustments are to sky cover (lower) and PoPs
(also lower). HRRR and other CAMs are picking up pretty well on the
lack of precipitation across the mountains, as the initial weak band
that developed is pretty much gone now. Zero CAPE to speak of so in
addition to slowing down the incoming pops pretty drastically, have
removed all mention of thunder.
Otherwise, by late tonight, low pressure is forecast to deepen
across PA, sweeping the front across the southern Appalachians
during the early morning hours, reaching the central Carolinas by
sunrise. South-southwest winds should remain ahead of the front,
then veering from the northwest in the wake of the boundary. The
environment should yield marginal instability across the
Appalachians, supporting showers and thunderstorms. East of the
mtns, it appears that showers will be limited to the NC foothills
and northern Piedmont. Low clouds may remain across the TN border
counties through Friday morning.
By mid Friday morning, shallow mixing should provide enough momentum
transfer to support gusts around 20 kts, gradually strengthening
through early afternoon. By mid day Friday, gusts are expected to
regularly reach into the 30s to mid 40 kts across the high terrain
and east facing mtn slopes. The strongest gusts will likely occur in
the wake of the mtns, with the forecast development of a mtn wave.
At this time, the window of gusts and coverage appears too limited
to highlight with a Wind Advisory, but we will monitor trends in
guidance. Otherwise, Friday will feature much lower temperatures,
highs ranging nearly 20 degrees cooler that today. Using a blend of
guidance, highs should range from the upper 50s across the mtn
valleys to low 70s across the upper Savannah River Valley. NW flow
may support ISO to sct showers across the TN border counties well
into Friday afternoon, I will highlight with SCHC to CHC PoPs.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 220 PM EDT Thursday: A weak short wave will move through an
upper trough and across the area Friday night and Saturday. At the
surface, a tight pressure gradient will be over the area between the
departing cold front and high pressure over the Mid-South. The
result will be very windy conditions across the mountains and breezy
to windy conditions elsewhere. With the cold advection Friday night,
expect 850 mb temps to bottom out slightly sub-freezing across the
mountains, but low level moisture still does not look very
impressive. Will still feature a ridge top rain/snow mix Friday
night and cannot rule out some light accumulations on Mount Mitchell
by Saturday morning where temperatures should fall into the upper
20s. A widespread Saturday morning freeze does not look likely in
the NC mountains and winds will be too high for frost formation so
no frost/freeze products will be issued. Elevations above 4000 feet,
however, could well see plenty of lower 30s temperatures. Any
lingering mountain precip will end quickly Saturday morning with
clouds slowly dissipating through the day. Sunny to mostly sunny
skies expected elsewhere. Windy to breezy conditions will continue
across the area as well. Highs will be 5 to 10 degrees below normal.
Heights begin to rise Sunday as the trough axis moves east of the
area. The surface pressure gradient will relax as well the center of
high pressure moves along the Gulf Coast. Winds should diminish
Saturday night, but will pick back up a little on Sunday as a lee
trough develops. A better chance of frost develops Sunday morning
across the mountains with the continued cold conditions and
diminished winds. Will have to keep an eye on the normally colder
locations outside of the mountains for frost development as
radiational cooling conditions improve. Highs will bounce back to
near normal.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 200 PM EDT Thursday...the extended period begins Sunday night
with the area under the influence of WNW flow and a weak surface
high centered over the southeast. Plentiful insolation and some
continued weak downslope flow east of the mountains will allow max
temps on Monday to climb to about ten degrees above average. A
clipper system will sweep through well to our north during the day
on Monday, pushing a backdoor cold front through by Monday night.
Though the frontal passage will feature no QPF response in our area,
it will bring min and max temperatures down closer to average levels
on Tuesday. An upper ridge will build in from the west by the middle
of next weak, keeping the region dry. Guidance is currently
suggesting a surface wedge will set up during the middle of the next
work week, maintaining temperatures near average levels.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Only change to the KCLT TAF for the 03z
AMD is to remove the lower VFR Cu for this evening. Otherwise, only
restrictions continue for KHKY and KAVL in closer proximity to the
front. Rain chances still not high enough to include prevailing SHRA
at this time so continued VCSH. S to SSW winds should continue this
evening and early overnight ahead of the front, but veering around
to NW Friday morning (current timing at KCLT is 14z). Post-frontal
mixing still looks like enough momentum transfer for decent wind
gusts tomorrow and for Friday afternoon have increased some of the
gusts through the end of the period.
Outlook: Pressure gradient will remain remain across the western
Carolinas through Saturday with breezy conditions. Dry high pressure
will build across the region on Sunday into early next week.
Confidence Table...
04-10Z 10-16Z 16-22Z 22-00Z
KCLT High 100% High 97% High 100% High 100%
KGSP High 100% Med 75% High 100% High 100%
KAVL High 100% High 100% High 100% High 100%
KHKY High 100% High 100% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% Med 75% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.CLIMATE...
RECORDS FOR 10-20
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 83 1985 42 1961 62 1950 25 1981
1972
KCLT 86 1926 49 1989 66 1993 30 1972
1910
KGSP 86 1899 50 1989 68 1894 29 1972
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...LEV
NEAR TERM...TDP
SHORT TERM...RWH
LONG TERM...LEV
AVIATION...TDP
CLIMATE...
Area Forecast Discussion
National Weather Service Lincoln IL
904 PM CDT THU OCT 20 2016
.UPDATE...
Issued at 904 PM CDT Thu Oct 20 2016
Showers progressing toward Indiana, with the band of showers
extending from Effingham to Paris at 9 pm. Timing tools show all
precip should depart our forecast area by midnight. The next
focus is on low temps tonight and potential for frost. Clouds are
slowly continuing to clear from west to east in western Illinois,
with winds diminishing below 10mph after clearing develops.
Surface dewpoints upstream in Iowa are in the 32 to 35F range, so
we should see our frost advisory areas have enough time later
tonight to dip into the mid 30s. Updated the cloud clearing trends
to slow them down slightly from previous forecast. That may allow
for slightly higher low temperatures east of I-57. Made minor
adjustments there, otherwise low temps look on track. High
pressure should provide mostly clear and cooler conditions
tomorrow, with highs only in the mid to upper 50s, with persistent
NW winds.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 303 PM CDT Thu Oct 20 2016
A vigorous short-wave trough evident on 19z/2pm water vapor imagery
over southern Iowa/northern Missouri will continue to track eastward
across the area this afternoon and evening. Enough synoptic lift is
being generated by this feature that weak radar returns are showing
up, suggesting the possibility of a few light showers or sprinkles.
Both the NAM and GFS show measurable precip developing across the
E/SE KILX CWA this evening as the wave passes through. Think this
may be a bit too aggressive, but will mention isolated showers
along/east of the I-57 based on current radar trends. Clouds will
hold firm into the early evening hours before gradually clearing
from west to east overnight. HRRR has been handling cloud trends
quite well, so have followed its solution closely. Skies will clear
to the I-55 corridor by midnight, then to the Indiana border by dawn
Friday. With skies clearing and a cool/dry airmass flowing into the
region, overnight lows will dip into the middle to upper 30s across
the western CWA. Think winds will decrease enough to allow the
formation of frost across the Illinois River Valley toward dawn.
Have therefore issued a Frost Advisory for all counties along and
west of the Illinois River. Further east, clouds will hold on long
enough to keep lows in the lower 40s. High pressure will slide
overhead on Friday, resulting in sunny skies and cool high
temperatures in the middle to upper 50s.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 303 PM CDT Thu Oct 20 2016
High pressure ridge will sit right over the CWA Friday night, and
with clear skies and light winds, frost will be a concern. Based on
the forecasted ridge axis, believe the best area for frost will be
in the eastern half of the CWA. Will probably need an advisory for
Fri night, but will wait til tomorrow to issue. High pressure will
dominate the area with dry weather through most of the weekend. A
frontal system will slide across northern half of the CWA on Sunday,
but there will be a lack of moisture, so no precip is expected when
this moves through. Behind this weak front, cooler high pressure
will move into the area for the first couple of days of the week.
Dry weather will continue as well. The next real chance of precip
will be beginning Tue night after midnight and then continuing into
Wed night. Earlier model runs differed on timing and location of the
precip; however, now models in better agreement. This system is
expected to move through quickly, so Thursday of next week should be
dry.
Besides the cool temps Fri night, seasonable temps will continue for
Sat and Sat night. Temps will then warm to above normal for Sunday,
before becoming seasonable again after the second high pressure area
moves in for next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 651 PM CDT Thu Oct 20 2016
Showers have departed to the southeast of CMI and DEC in the last
hour, and dry conditions should prevail for the remainder of this
TAF period under advancing high surface pressure. Clouds will
continue to clear from west to east this evening, with all areas
clear by 05z/midnight. The only sites with MVFR clouds at TAF
issuance time are BMI, CMI and DEC, with improvement to VFR by
late evening. NW wind gusts of 15 to 25kt will diminish by 02z,
but sustained NW winds are expected to remain at 10-12kt for much
of the night for all sites except PIA. The pressure gradient in
western IL looks to become weak enough after 09z along and west of
the Illinois river for winds to diminish below 10kt and areas of
frost to form. NW winds will hover in the 08-12kt range tomorrow
under mostly clear skies.
&&
.ILX Watches/Warnings/Advisories...
Frost Advisory from 4 AM to 8 AM CDT Friday for ILZ027>031-036-
037-040-041-047.
&&
$$
UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Indianapolis IN
1020 PM EDT Thu Oct 20 2016
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 149 PM EDT Thu Oct 20 2016
Low Pressure over kentucky late this afternoon will push northeast
tonight...dragging a cold front along the Ohio River father
southeast. As the low departs the area...rain across Central
Indiana will taper off during the evening hours.
High pressure over the Central Plains states is expected to build
across the region...bringing a blast dry weather and seasonal
fall temperatures.
The dry weather is expected to persist through the weekend and at
least into early next week.
&&
.NEAR TERM /Rest of Tonight/...
Issued at 958 PM EDT Thu Oct 20 2016
UPDATE...
Current forecast is on track, so no changes were needed. Current
temps across the area are ranging from the low to mid 50s and are
projected to dip into the low to mid 40s. Current radar mosaic
shows some lingering showers across the forecast area, but they
should taper off overnight. Updated grids have been sent.
PREVIOUS DISCUSSION...
HRRR Continues to suggest lingering precipitation across the
forecast area through the late afternoon. However after 00z best
moisture will be rapidly departing the area. forecast soundings
and time heights do shows lower level moisture lingering through
the evening hours...but lift should be much weaker as best forcing
and dynamics should depart rapidly to the northeast. Best chance
for precip after 00z may be with the tail of the system...seen at
the moment as some light showers across Missouri. None the
less...will taper pops lower as the night progresses.
As the cold front sags southward...strong Cold air advection
continues to stream into central Indiana. 850MB temps show values
falling to near 2c by 12Z Friday. Thus will trend toward the
cooler MAVMOS lows.
&&
.SHORT TERM /Friday through Sunday/...
Issued at 149 PM EDT Thu Oct 20 2016
Dry weather is expected this period.
After the departure of the broad trough in place across the area
on Friday...GFS and NAM suggest Strong ridging to build across the
western plains and slowly spill eastward...placing The Ohio
valley in a broad area of lee side subsidence, Forecast soundings
through Sunday show a dry column....with fair weather CU/SC
expected on Friday...and unattainable convective temperatures on
Saturday and again on Sunday. Thus will aim for Partly sunny
Friday and Mostly sunny on Saturday and Sunday. The quick NW flow
aloft should allow a few passing high clouds through the
period...although this should have no impact.
As for temps...the Cool air in place behind the front will linger
across the area before Warm air advection is expected to begin on
Saturday. Furthermore additional sunshine on Saturday an Sunday
should allow a slow modification of the cooler air mass.
Additionally as the surface high passes to our east on Saturday
night and Sunday...Warmer return flow will develop within the
lower levels. Thus look for Friday to be the coolest day...with
daytime high trending higher each day through Sunday.
&&
.LONG TERM /Sunday Night Through Thursday/...
Issued at 201 PM EDT Thu Oct 20 2016
Models are close enough that the SuperBlend initialization was
accepted for most items.
A cold front will bring some cooler air early in the week, but
lack of moisture will keep conditions dry. The quiet weather can be
expected until mid week, when a low pressure system could bring some
showers to the area Wednesday afternoon into early Thursday.
Temperatures will be near to above average.
&&
.AVIATION (Discussion for the 210300Z IND TAF Update)...
Issued at 1020 PM EDT Thu Oct 20 2016
No changes needed to the TAF.
Previous discussion follows...
Issued at 702 PM EDT Thu Oct 20 2016
Kept VCSH or showers in the main group through 03z-04z. Moderate
confidence that MVFR ceilings will improve to VFR 08z-10z. Northwest
winds will remain around 10 knots and should keep fog from being an
issue. Finally, Cu development progs suggest diurnal VFR cu Friday
afternoon.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA/TDUD
SHORT TERM...PUMA
LONG TERM...50
AVIATION...MK
Area Forecast Discussion
National Weather Service Blacksburg VA
1030 PM EDT Thu Oct 20 2016
.SYNOPSIS...
A cold front will slowly move into the region from the west tonight,
then exit the area to the east late Friday morning. This will spread
showers and possibly a few thunderstorms across the Appalachians and
central mid Atlantic region later tonight into Friday. Strong gusty
winds behind the front will usher in much colder air for the weekend,
and some wet snowflakes are possible at the higher elevations west
of the Blue Ridge.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 915 PM EDT Thursday...
Have scaled pops back quite a bit over the next few hours. Short
range and longer range synoptic models really do not bring the
bulk of the precipitation into the CWA until 10Z or later, mainly
after 12Z. The exception is an area of scattered showers
developing out ahead of the main area across eastern WV southwest
into northeast TN and far southwest VA. This activity largely
driven by daytime heating and instability and will likely go away
in the new couple of hours, per HRRR and NSSL WRF. Also confined
mention of thunder to areas west of I-77, mainly during the next
3-4 hours before instability wanes to 400 J/kg of CAPE or less.
Temperatures across the Piedmont have cooled a little quicker than
areas further west where it is cloudy. Essentially a reversed
pattern from normal at this time of evening. Feel that Piedmont
temperatures will level off as clouds move in that direction, and
may actually increase slightly before the night is over as clouds
overspread that area as well. The net result will be min temps
fairly close to what was previously advertised. The other
consideration is max temps for Friday. Latest GFS/HRRR suggest
that it could still be well into the 70s across the eastern parts
of the Piedmont during the afternoon Friday.
As of 330 PM EDT Thursday...
Expect quiet weather into this evening before the cold front
approaching from the west can start to push some showers into the
region. Guidance continues to trend slower with this system and the
bulk of the precipitation looks to remain west of the Blue Ridge until
well after Midnight. However, there will be a tight gradient to the
precipitation so a few miles either way will make a big difference as
to whether locations far west of the Ridge making it into some decent
rainfall earlier tonight. Steep lapse rates aloft will also make for
the possibility of some embedded thunder especially far west, with the
thunder chances decreasing overnight.
The front looks to be right along the Ridge by daybreak, but the best
forcing will be shearing off to our north. This is expected to weaken
the precipitation considerably as it progresses east of the Ridge but
some redevelopment of convective elements will be possible in the
piedmont early in the afternoon. Conditions will improve as the front
departs, but upslope winds will keep scattered going west of the Ridge
through Friday afternoon.
Winds behind the front will shift around to the northwest and favorable
momentum transfer indicated in model soundings will make for quite
gusty conditions, especially at the higher elevations from the Blue
Ridge westward. Expect the winds to be on the increase after daybreak
and continue blowing throughout Friday.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 330 PM EDT Thursday...
This portion of the forecast to be dominated by sharp upper trough
rotating across the mid-Atlantic region with attendant cold front
pushing well off the east coast east Friday night into Saturday.
Lingering rain and few high elevation snow showers will persist into
early Saturday with a diminishing trend as the day progresses. 850mb
temps fall below 0C Friday night and should allow for some snow or
mixed precipitation in the elevations above 3000 ft. as noted.
Strong winds may well be the most notable feature of this system as
deepening low over the northeast increases pressure gradient through
Saturday. Wind gusts over 30 mph will be common through this period.
In addition some of the coolest temperatures of the season to date
are expected although that is not saying much given the
extraordinary persistence of above normal temperatures over the past
six to eight weeks. Lows Saturday morning upper 30s to low 40s and
similar on Sunday morning. No widepspread frost or freeze is
anticipated as clouds and wind Friday night and wind Saturday night
persist enough to maintain mixing and poor radiational conditions
both mornings. The lows in fact will be right around the long-term
normals for the 3rd week in October. Saturday will feel quite chilly
perhaps owing to clouds/wind and highs from mid-40s west to near 60
east. Those are 5-10F below normal.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 330 PM EDT Thursday...
Surface low pressure and associated upper system will be located
over southeast Canada on Sunday with the flow across the lower 48
beginning to flatten out into a zonal pattern. This will promote a
rather dry week ahead with few temperature extremes. A mostly dry
front will push south across the area on Monday with only the
slightest chances for some light precip in the far northwest. Not
until about late Thursday does another front organize over the
midwest and begin advancing eastward. This front looks to arrive
early Friday with timing not too dissimilar to tonights frontal
passage and again with best dynamics and deeper moisture to our
north.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
As of 750 PM EDT Thursday...
Clearly the main focus through this TAF valid period will be on a
strong frontal system and negatively tilted upper trough slated
to cross the region overnight and early Friday. Timing has slowed
down on all models and this is in good agreement with current
radar analysis. Thus, while some pop up showers are expected
across southwest VA/southeast WV over the next few hours per HRRR
and NSSL WRF, the main line of convection is not expected to reach
the western part of the CWA until just before daybreak, into the
KBCB/KROA area in the 12Z-13Z time frame, and into the Piedmont
between 14Z and 16Z. With this in mind, there should be little no
potential for any thunder as all instability of significance is
gone within the next few hours. Having said this, it is still
possible to get a rumble of thunder from elevated instability, but
not worth putting in the TAFs at this point.
Thus, cigs/vsbys are largely expected to remain VFR over the next
few hours, with BKN-OVC cigs AOA 040 mainly west of a KBCB-KLWB
line, with cigs AOA 050 further east across the Piedmont. Starting
around 09Z, -SHRA will arrive in the western parts of the CWA at
which points cigs will lower into the MVFR and then IFR range by
12Z with vsbys dropping into mainly the MVFR rain in -SHRA. Cigs
will drop into the MVFR range further east after 12Z accompanied
by a period of -SHRA and MVFR vsbys as well. The initial line of
showers/convection will lift out of the eastern areas by early
afternoon, but upslope showers will continue across the western
mountains. While there may be a brief break in the showers western
areas during the early afternoon, there is clear evidence of a
deformation zone and moisture wrapping back into these areas as
the upper trough takes on a negative tilt and rotates through the
region during the afternoon. At times, given the site setting at
KBLF, expect the cigs to drop to observation height and the cigs
to drop below 005 and vsbys to drop to LIFR.
Further east across the Piedmont, cigs should improve to high end
MVFR or low end VFR after 18Z with no further restrictions to
vsbys at that point.
Until the front passes daybreak or later, winds will be mostly
SSE-SSW 4-8kts, highest in the western areas. After the frontal
passage, winds will become WSW-WNW 10-15kts with gusts 22-30kts.
Winds will likely be stronger on Saturday with better mixing and
insolation than what we will see on Friday.
Medium confidence in cigs and vsbys throughout the TAF valid
period.
Medium to high confidence in wind direction/speed throughout the
TAF valid period.
Extended aviation discussion...
A return to VFR conditions is expected for most areas Friday
night into Saturday. The exception will be western parts of the
region where a healthy northwest upslope flow, and lingering low
level moisture, will prolong an IFR/MVFR ceiling during this time
period. Even the mountain areas will become VFR again for Sunday
and Monday.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...MBS
NEAR TERM...MBS/RAB
SHORT TERM...PC
LONG TERM...DS/PC
AVIATION...RAB
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Friday)
Issued at 212 PM CDT Thu Oct 20 2016
Mid level trough axis continues to translate eastward this afternoon
while a drier airmass upstream filters southward into northeast
Kansas. Most of the stratus deck has dissipated to the south with
some diurnal cumulus noted over north central areas. As the center
of the sfc ridge axis enters northern Kansas within the next few
hours, northerly winds will calm through the evening. Expect to see
clearing skies as temperatures quickly drop back into the 40s by
midnight. Some uncertainty on how well the low levels decouple
overnight as light northerly winds veer towards the south by
sunrise. Short term HRRR and RAP are not as cool with readings near
40 degrees while the MOS guidance is trending towards the middle 30s.
Went closer to MOS, especially with the calm winds and clear skies.
Patchy frost is possible generally east of highway 75 through
sunrise.
On Friday, dry northwest flow builds into the region at 500 mb.
Sfc trough deepens east into the western high plains, enhancing the
southerly winds over north central KS. Speeds between 15 and 20 mph
sustained are expected with gusts in excess of 25 mph possible.
Elsewhere, 10 to 15 mph sustained with gusts around 20 mph is
likely. Slightly better mixing with sunshine throughout the day
should result in highs from the lower 60s east to upper 60s west.
.LONG TERM...(Friday night through Thursday)
Issued at 212 PM CDT Thu Oct 20 2016
Sfc high pressure will slide off to the east Friday night leading
to warmer and windy conditions through Sat night. A weak cold
front will sag into the region on Sunday however lack of moisture
and large scale forcing will keep conditions dry and the only
impact will be a decrease in winds on Sunday. Return flow with
increasing south winds will establish across the region on Monday
with the next shortwave still forecast to move across the area
next Tues and Weds. Sufficient moisture should return to allow
some precip to develop ahead of the wave and associated sfc front
mainly Tues night into early Weds.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 616 PM CDT Thu Oct 20 2016
VFR conditions expected through the taf period. There may be
occasional wind gusts around 20 kts during the day tomorrow
especially at MHK.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Prieto
LONG TERM...Omitt
AVIATION...Sanders
Area Forecast Discussion
National Weather Service Goodland KS
203 AM MDT Fri Oct 21 2016
.SHORT TERM...(Today through Sunday night)
Issued at 202 AM MDT Fri Oct 21 2016
Early morning WV imagery and RAP analysis shows large scale
ridging building across the western US into the plains, with NW
flow over the Central High Plains. At the surface, high pressure
has slid east of our CWa towards the southern Missouri River
valley. Lee trough has redeveloped and southerly surface gradient
is in place over our CWA.
Regarding frost advisory this morning: Temps have already dropped
to low to mid 30s at multiple locations across our CWA (upper
bound of, which is already faster than the forecast diurnal curve
indicated. Southerly winds 10-15 mph are leading to better
mixing/higher temps elsewhere, but further decoupling should
result in a gradual decrease in winds by sunset. There is still
enough time for winds to drop off and temps to quickly fall to the
lower 30s across our entire CWA due to mostly clear skies and Tds
in the 20s to lower 30s. Will keep frost advisory in place as it
is, and let it run it`s course as frost conditions are still
likely through the morning.
Today-Sunday night: Mid to upper level ridging across the southern
US will dominate sensible weather. A very deep dry air mass will
remain in place, with cross mountain flow along northern part of
ridge. A shortwave trough rotating through the Northern Plains
near the US/Canada border, and it`s associated (weak) cold front
will drop south Saturday night. Despite periods of weak forcing
the dry/stable air mass will preclude any precipitation chances.
Above normal temperatures are expected through these periods with
the warmest day on Saturday when highs will reach the lower 80s
for parts of our CWA.
.LONG TERM...(Monday through Thursday)
Issued at 202 AM MDT Fri Oct 21 2016
Predominantly dry weather continues during the extended period
with above normal high temperatures in the 70s. Low temperatures
start off in the 40s to low 50s before decreasing into the upper
30s to mid 40s.
On Monday, the upper ridge dominating the pattern progresses east
of the region, keeping conditions dry. However, the ridge breaks
down on Tuesday as a stronger disturbance passes through the
southwesterly flow. This generates precipitation chances for the
central Plains. At this time, it appears the better chance for
precipitation will be east of the region, with only a slight
chance of showers and thunderstorms clipping the extreme eastern
portion of the forecast area Tuesday afternoon and evening. After
this brief opportunity for some rain, the ridge rebuilds over the
region, bringing near zero PoPs back to the forecast on Wednesday
and Thursday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1000 PM MDT Thu Oct 20 2016
For KGLD and KMCK, vfr conditions expected through the period.
KGLD, ASOS is reporting 3-4sm in haze, this is an incorrect report
and suspect its spider webs. We have the ability to turn it off
but am not sure how it impacts inbound and outbound flights. So,
will keep it on and have P6SM in the taf. Otherwise similar
forecast to 00z forecast. Winds from the south near 10kts veering
to the southwest then west through mid day Friday. After 18z winds
become northwest then northeast at speeds under 10kts as sfc
trough moves through. For the evening hours winds from the
southeast then southwest at speeds under 6kts. Only some high
clouds expected.
KMCK, similar scenario as KGLD regarding winds and timing of upper
trough passage. Speeds through the period under 10kts.
&&
.FIRE WEATHER...
Issued at 202 AM MDT Fri Oct 21 2016
Very dry air mass and above normal temperatures will lead to
afternoon RH values dropping to 15 percent or lower for parts of
our CWA. Daytime winds are not expected to reach or exceed
critical criteria. We could have a few brief periods of 20 mph
gusts midday Saturday, but this would likely occur while RH values
are still 20 percent or higher. Critical fire weather conditions
are not expected at this time.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Frost Advisory until 9 AM MDT /10 AM CDT/ this morning for
KSZ001>003-013>015-027>029-041-042.
CO...Frost Advisory until 9 AM MDT this morning for COZ090>092.
NE...Frost Advisory until 9 AM MDT /10 AM CDT/ this morning for
NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...JBH
AVIATION...99
FIRE WEATHER...DR
Area Forecast Discussion
National Weather Service Wilmington NC
403 AM EDT Fri Oct 21 2016
.SYNOPSIS...
Mild weather will prevail through today before chillier air behind a
cold front comes crashing into the eastern Carolinas Friday night.
The weekend will be characterized by seasonably cool temperatures
with lows in the 40s and highs remaining below 70 degrees Saturday
and Sunday. A brief warm-up Monday will be followed by a reinforcing
shot of dry and cool air Monday night. This will set the stage for
dry and fair conditions in the upcoming week with temperatures near
normal for the season.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Friday...Major changes on the way for the ILM CWA.
Morning will start out like previous mornings...mild with 60s for
temps. Some clouds may be seen across the western portions of the
ILM CWA due to the approaching eastward moving cold front. The main
dynamics associated with the upper s/w trof approaching stay north
of the ILM CWA as well as it`s associated sfc low. The further south
from the sfc low one goes, the moisture availability lowers. The FA
will be in the Right Rear quadrant of the upper jet this afternoon
and combined with strong frontal dynamics should produce 15 to 34
percent chance for showers with isolated thunderstorm possible
mainly across the ILM NC CWA. For the most part, HRRR and RAP models
remain on the lower side of pcpn chances whereas the Hi res wrf
is much more wetter. Will stay closer with the drier bias. The
strong cold front will reach the western portions of the ILM Late
this morning and by late this afternoon or early evening the cold
front will have pushed off the mainland.
Light sw-w winds ahead of the front will switch to the nw and
increase dramatically to w to nw 10 to 20 mph with hier gusts.
Winds will become nw thruout tonight at 10 to 20 mph speeds with the
hier speeds closer to the coast. The tightened sfc pg and caa will
combine to keep winds gusty at times thru the night. The caa can be
seen with 850mb temps that drop from roughly 13 to 15 degrees
celsius midday today to 4 to 5 degrees celsius by daybreak Sat.
This also goes along with the tight packing of various thickness
schemes that advect across the ILM CWA, ie. 1000-850mb thickness.
Stayed closer to the slightly hier European Mos guidance for todays
highs. However, did a blend of the various models for tonights mins.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 330 AM Friday...The change in the upper longwave pattern early
in this period will result in upper troffing affecting the Eastern
U.S. basically from the Great Lakes eastward and with upper ridging
across the western 2/3rds of the U.S. The mean upper trof axis will
lie off just off the East Coast of the U.S. No mid-level s/w trofs
are expected to affect the ILM CWA this period. With this pattern,
pcpn chances will be null and void. For Saturday, at the sfc, the FA
will be under continued gusty NW winds that will slowly abate during
the aftn and evening. With the center of high pressure progged to
drop to the Gulf Coast States for Sunday, winds will not totally
drop out but will subside from what transpired during the day on
Saturday. Sky conditions thru the period will be clear any cloud
that makes it across the Appalachians will scour out quickly under
NW downslope trajectory flow. For now will use a blend of the
available model data for max/min temps thruout this period. Not
entirely bought on any 1 Mos guidance given the change in airmass.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 300 AM Friday...A rebound in temps into the mid 70s for
early in the week in light W-SW flow will be knocked back down
once again as a dry cold front drops south through Mon aftn. This
boundary is barely evident when looking at pcp water field as the
values rise from around a half inch up to .75 inch right along it.
Do not expect any pcp with this front. N-NW will follow as High
pressure builds in behind it, but ridging in the upper atmosphere
and bright October sunshine will offset the cooling to produce
temps around 70 most places. High pressure will shift off the east
coast on Thurs with a W-SW return flow allowing temps to warm once
again. Overall dry weather with plenty of sunshine through the
week.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
As of 06Z...Enough shallow moisture combined with clear skies and
calm winds will produce another morning of fog across the terminals.
Expect fog to clear by 13z across terminals with light westerly
winds to start the day. A strong cold front will move through the
area from west to east on Friday. Winds will back slightly ahead of
front but will become gusty out of the west as it approaches and
although the front does not have much upper level support, have
included showers in vicinity. Cannot rule out a possible
thunderstorm. Look for fropa through mid aftn inland terminals and
late aftn to early eve coastal terminals with rapid clearing,
moderate cold air advection and gusty northwest winds to follow.
Extended Outlook...VFR to prevail Sat-Tue.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Friday...SCA has been raised for the SC waters by mid
afternoon and the NC waters by early evening.
The story for mariners will be initially the easterly swell
affecting the local waters from the low now roughly located about
400 miles southeast of Cape Fear. Weak showers rotating around this
low could reach the local waters from the east this morning before
drying up. This low is progged to turn NE, hooking up or in this
case getting absorbed with the strong cold front, well NE of the
local waters, associated with the progressive upper s/w trof.
The main story for mariners will be the passage of the strong cold
front late this afternoon or early evening followed by the tightened
sfc pg after the cfp that will last across the local waters thru
tonight. With excellent CAA after the cfp, this will combine with
the tightened sfc pg to produce strong SCA conditions with possible
Gale force wind gusts especially off Cape Fear or Cape Romain.
Significant seas will build late this afternoon and tonight due to
building wind driven waves.
The easterly swell from the exiting low will continue to affect the
local waters tonight which may boost seas a little higher than what
guidance is dictating.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 330 AM Friday...Winds are expected to remain active thruout
this fcst period. The highest NW winds are slated on Saturday due to
the tightened sfc pg and continued or reinforcing CAA across the
local waters. The center of the sfc hi drops to the Gulf Coast
States Saturday night and remains in this position into Monday.
The sfc pg does slightly relax additionally with neutral advection
to occur. Winds will peak Sat and lower to below SCA thresholds by
sunset Saturday for all waters. Winds will slightly lower further on
Sunday thru Sunday night backing to a more westerly direction around
15 kt. Significant seas will peak early Saturday then slowly drop
off as the easterly swell from the exiting low subsides and
partially decays. Wind driven waves will still remain the dominant
producer of the sig. seas thruout this fcst period. Should see a
nice range of seas Saturday thru Saturday evening then become more
uniform during Sunday into Sunday night.
LONG TERM /MONDAY THROUGH TUESDAY/...
As of 300 AM Friday...Light W-SW winds early Monday will veer to
the NW as a dry cold front moves across the waters Mon aftn.
Another surge of cool air as high pressure builds down from the
north behind front. Expect winds to kick up out of the N-NW from 15
to at least 20 KT Monday night shifting to the N-NE by Tues as
high pressure migrates east as it extends down from Canada. WNA
showing seas remaining below SCA thresholds running 2 to 3 ft
ahead of front early Mon and then jacked back up to 4 to 5 ft Mon
night into Tues in gusty northerly winds.
&&
.EQUIPMENT...
As of 300 AM Thursday...The ASOS at the Lumberton, NC airport
(KLBT) has no power and the emergency generator which had
maintained power since Hurricane Matthew has run out of fuel. LBT
is awaiting a fresh supply of fuel so the equipment can be up and
running again.
Observations and climate data from Lumberton will remain missing
until further notice.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
NEAR TERM...DRH
SHORT TERM...DRH
LONG TERM...RGZ
AVIATION...RGZ
Area Forecast Discussion
National Weather Service Melbourne FL
452 AM EDT Fri Oct 21 2016
.DISCUSSION...
...Much cooler temperatures tonight and into this weekend with lows
in the 50s...
Currently...Area of stratus/fog with localized visibilities of a
half a mile or less has developed over and west of the I-4 corridor
through Lake, Volusia, Seminole and Orange counties. Latest HRRR
shows this fog should persist and expand slightly, possibly into
northern Osceola County through sunrise, then quickly diminish into
mid morning. Will continue to monitor visibilities in this area and
dense fog becomes more widespread, may need to issue a short fused
Dense Fog Advisory for northern portions of east central Florida.
Today-Tonight...Low pressure (Invest 99L) well east of the area
will lift north-northeast today, eventually merging with a cold
front that will push off the eastern seaboard and across central
Florida into tonight. Airmass will be quite dry over the area
today with only a modest increase in moisture as front approaches,
but with winds already out of the N/NW little low level
convergence will exist for any precipitation with this boundary.
The exception will be over the coastal waters where models
indicate a few showers developing offshore into tonight as front
moves through. Highs will again be warmer than normal today, in
the mid to upper 80s, then much cooler air will filter in behind
the front overnight. Lows are forecast to drop below the 60 degree
mark over Volusia County and much of the interior for this first
time in 5 months, with min temps likely holding in the low-mid 60s
along coastal sections from Cape southward.
Sat-Sun...Behind the cold front, high pressure centered over the
lower Mississippi Valley will build eastward with a ridge axis
extending into the western Atlc. Thus, north winds on Sat will
veer to the northeast Sun. Low temps on Sunday are tricky near the
coast as 925 mb winds veer quickly to an onshore (NE) component,
while surface winds remain light NNW. Have trended cooler near the
coast (Brevard southward) but have stayed a couple/few degrees
warmer than GFS and ECMWF MOS. The coolest air since early May is
expected Sunday morning with lows dipping into the 50s over much
of the area, except low/mid 60s along the immediate coast south of
the Cape. Highs both days will be slightly below normal ranging
from the mid 70s to around 80 degrees.
Mon-Thu...The high pressure ridge just north of the area will
weaken Mon as a frontal boundary pushes off the eastern seaboard.
Strong high pressure over the Great Lakes will build south and
east and produce an increase in E/NE flow Tue through Wed.
Increasing moisture and onshore flow will produce higher shower
chances esp near the coast Tue night and Wed with the best chance
along the Treasure coast on Wed. The stronger and more persistent
onshore flow will produce milder temperatures in the lower 80s and
noticeably warmer low temps in the mid to upper 60s, except lower
70s along the coast.
&&
.AVIATION...IFR/localized LIFR conds will continue across much of
Lake, Volusia, Seminole, and Orange counties through daybreak
with area of stratus and fog that has formed over this region. Fog
may continue to expand slowly southward during this time, but
should quickly diminish after sunrise into mid morning.
Otherwise VFR conds are expected across the region into tonight. A
cold front will move across the area late day into tonight, but
any precipitation will be limited to the offshore waters.
&&
.MARINE...
Today/Tonight...Northwest winds up to 10-15 knots will continue
over the waters today with seas up to 6-7 feet away from the
coast. Winds and seas may diminish slightly for a brief period
late today, but a cold front will cross the waters tonight with a
surge in northerly winds, up to around 20 knots, expected behind
the boundary increasing seas to 7-8 feet offshore. Small Craft
Advisory for the offshore waters has been extended into tonight
for these hazardous boating conditions.
Sat-Tue...Northerly wind surge up to 20 knots behind the cold
front will continue into the first half of Saturday, keeping
boating conditions poor especially offshore and in the Gulf
Stream. Winds will veer and develop an onshore component by
Sunday while decreasing to around 15 knots. With a continued
northerly component, seas will remain choppy, especially in the
vicinity of the Gulf Stream.
Northeast flow 10-15 knots Mon-Tue with seas 3 to 4 feet.
&&
.HYDROLOGY...
The St. Johns River at Astor (2.85ft) remains in Minor Flood
Stage this morning. The river is forecast to fall below flood
stage (2.8 ft) today or tonight, but remain above Action Stage
(2.5ft) through this weekend.
At Geneva/above Lake Harney, the St. Johns River will remain near
7.0ft through this weekend, keeping it in Action Stage.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 87 58 75 53 / 10 0 0 0
MCO 87 59 77 55 / 0 0 0 0
MLB 85 63 78 59 / 0 0 0 0
VRB 85 64 78 59 / 0 10 0 0
LEE 86 59 76 52 / 0 0 0 0
SFB 87 59 77 55 / 0 0 0 0
ORL 87 60 77 58 / 0 0 0 0
FPR 86 63 80 59 / 0 10 0 0
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 8 PM this evening to 8 AM EDT Saturday
for Flagler Beach to Volusia-Brevard County Line 20-60 nm-
Sebastian Inlet to Jupiter Inlet 20-60 nm-Volusia-Brevard
County Line to Sebastian Inlet 20-60 nm.
Small Craft Advisory for hazardous seas until 8 PM EDT this
evening for Flagler Beach to Volusia-Brevard County Line 20-
60 nm-Sebastian Inlet to Jupiter Inlet 20-60 nm-Volusia-
Brevard County Line to Sebastian Inlet 20-60 nm.
&&
$$
SHORT TERM...Weitlich
LONG TERM....Kelly
Area Forecast Discussion
National Weather Service Marquette MI
431 AM EDT Fri Oct 21 2016
.SHORT TERM...(Today and tonight)
Issued at 426 AM EDT FRI OCT 21 2016
A mid-upper level trough over the area this morning will move east
of Upper Mi later this afternoon as it is replaced by a mid-upper
level ridge from the west. A northerly flow of colder air (h85 temps
to -5C) ahead of a sfc ridge centered over western Lake Superior has
generated isolated to scattered lake effect rain showers over nw and
n central Upper Mi early this morning. Not out of the question
that some light snow could briefly mix in over higher terrain areas
west of Marquette this morning.
Today, weakly cyclonic northerly flow and fairly deep moisture to
around 750 mb as noted on NAM and RAP fcst soundings will continue
to support isolated to scattered lake effect showers into this
afternoon over mainly central Upper Mi. Weakening northerly flow
with the eastward advance of the sfc ridge into central Upper Mi
along with a slightly lowering subsidence inversion should diminish
showers later this afternoon and end showers by the evening hours.
Expect highs in the 40s.
Tonight, Expect dry conditions with ridging aloft and at the sfc. A
shortwave now over the Northern Rockies is expected to ride across
the Canadian/northern CONUS border today and then weaken/shear out
as it moves through the mid-level ridge over the western Great Lakes
later tonight. Models fairly consistent showing best moisture and q-
vector convergence associated with incoming shortwave will be shunted
nw into Ontario. As a result, expect just some increase in mid clouds
over the west with dry conditions prevailing. Min temps will range
from the mid 20s over the central interior under cloud free skies of
the sfc ridge to the mid to upper 30s far west where increasing
clouds and onset of downsloping southerly winds on backside of
ridge will keep temps warmer.
.LONG TERM...(Saturday through Thursday)
Issued at 342 AM EDT FRI OCT 21 2016
A relatively benign wx pattern is expected to dominate in the
medium/extended range. The period into early Sun should be dry with
lingering sfc pres dominating. Some showers could impact Upr MI on
Sun ahead of an aprchg disturbance, with some lk effect showers psbl
on Sun ngt into Mon in its wake. But any pcpn should be lgt during
this period. Then sfc hi pres near the upr confluence on the wrn
flank of a deep, slow moving upr trof in Quebec is likely to bring a
period of dry wx later Mon thru at least Tue and perhaps Wed if the
next shrtwv moving toward the wrn Great Lks is shunted far enuf to
the sw by the slow moving hi pres. More showers are psbl at the end
of next week as another shrtwv aprchs fm the nw.
Sat...Some waa in the ssw flow btwn a sfc hi pres rdg over ern Upr
MI and a shrtwv/lo pres tracking thru far nw Ontario wl bring some
clds to the cwa. Some of the models even generate some lgt pcpn, but
lingering near sfc dry air associated with persistent h5 rdg axis/
the sfc hi pres rdg held in place on the wrn flank of deep lo pres
in New England and passage of the shrtwv/sharper forcing so far to
the n favor a dry fcst for Upr MI. H85 temps recovering to arnd 5C
over the wrn U.P. wl allow for a warmer aftn despite the clds.
Sat ngt thru Sun ngt...Most of the medium range guidance show a
fairly strong shrtwv embedded in the fast wnw flow aloft near the
Cndn border on the nrn flank of upr rdg in the Plains and associated
sfc lo pres moving near the Upr Lks during this time. Clds in
advance of this disturbance wl roll into the area on Sat ngt.
Despite some fairly impressive dpva/deep lyr cnvgc/band of h85-7
fgen ahead of this feature, absence of any sgnft mstr return wl
restrict accompanying pops/qpf. There are some fairly sharp
differences on the track/intensity of the shrtwv and sfc lo pres.
With a more confluent nw flow aloft just to the e on the wrn flank
of the deep lo pres track tracking slowly n thru Quebec, suspect the
weaker/quicker/farther s depiction of the sfc lo shown by the 00Z
GFS/12Z ECMWF is on the right track. This scenario would further
reduce pops. But considering the uncertainty in the fcst, maintained
consensus fcst for now. A colder nw flow in the wake of the
departing disturbance and in advance of trailing hi pres that wl
drop h85 temps toward -5 to -6C could bring a return of some lk
effect clds/showers on Sun ngt. Lowering invrn base under 5k ft agl
in the overall subsidence left in the wake of the departing shrtwv
wl restrict the intensity of any lk effect pcpn. But upped consensus
fcst pops into the lo chc category to reflect this potential in the
areas favored by the nw flow to the e of Marquette, where a longer
fetch acrs Lk Sup wl allow more moistening of the incoming airmass.
Shorter fetch into the w as well as a more acyc/diffluent llvl flow
closer to the incoming hi pres rdg should maintain dry wx there even
if there are some sc near the invrn base.
Next week...Some lk effect clds/showers could linger over the e into
Mon in the nw flow ahead of aprchg hi pres. But as this sfc hi pres
shifs into the Great Lks on Mon ngt into Tue under a bldg upr rdg
left in the wake of slowly departing upr trof/sfc lo pres in ern
Canada, expect a period of dry wx. If the hi pres rdg/axis of pwat
under 0.50 inch is ovhd on Mon ngt with lgt winds/moclr skies, Tue
mrng could be quite chilly. Many of the previous medium range models
showed waa clds invading the area by then on the wrn flank of a
faster exiting sfc hi pres along with some lgt pcpn on Tue, but
model trends appear to be for a slower moving sfc hi pres and dry wx
persisting thru Tue. Considering the deep lo pres near the Cndn
Maritimes/deep upr trof in Quebec, suspect the slower moving sfc hi
pres/longer dry period is the way to go. So lowered fcst min temps
at most places over the interior blo the consensus fcst. Although
another shrtwv is fcst to drift e thru the ncentral Plains toward
the Upr Midwest on Wed, the persistence of the slower moving sfc hi
pres/dry airmass may shunt the accompanying sfc lo pres/deeper mstr
far enuf to the s-sw to maintain dry wx over much of the cwa thru
Wed. Another shrtwv dropping into the Great Lks next Thu/Fri could
bring some showers then. Expect no sgnft temp departures fm normal
next week except for the potential for some chilly mrngs on Tue and
perhaps Wed if the sfc hi pres is more resilient.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 205 AM EDT FRI OCT 21 2016
Cold air moving through the area will generate lake effect clouds
and pcpn with variable CIGs and isolated showers. CIGs will lower
late tonight into Fri as a trough moves through the area, leading to
increased lake effect rain. Dry air will only slowly move in Friday
afternoon with a returned to sct clouds and VFR conditions from
west to east.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 426 AM EDT FRI OCT 21 2016
No significant low pressure systems are expected to move through the
Upper Great Lakes in the next several days. Winds will remain below
gales through the period. A tightening gradient between a deep low
pressure system moving through Quebec and a high pressure ridge
building into the Plains could lead to a period of nw winds to 30
knots over north central and eastern Lake Superior late Sunday into
Monday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Voss
LONG TERM...KC
AVIATION...JLB
MARINE...Voss
Area Forecast Discussion
National Weather Service Taunton MA
1031 AM EDT Fri Oct 21 2016
.SYNOPSIS...
Sub-tropical low pressure lifting north toward southern New
England will bring numerous showers and isolated t-storms with
locally heavy rainfall this afternoon and tonight. Additional
showers are likely Saturday as the storm moves into northern New
England along with strong winds developing late Saturday into
Saturday night. Dry but cool and blustery conditions Sunday into
early next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 am update...
Warm sector continues to surge northward thru the coastal plain of
CT/RI and southeast MA at 10 am. Some brief clearing in the warm
sector has allowed temps to soar into the low 70s at 10 am.
However this will be short lived as visible satellite imagery and
radar show clouds and showers just south of the islands and
streaming rapidly northward. Thus sunshine across eastern CT/RI
and southeast MA will be short lived and replaced by clouds and
showers midday or shortly thereafter.
Warm sector will continue advecting northward but will likely
stall somewhere across northern MA as pres falls and associated
cyclogensis evolve south of New England later today. Thus tricky
temp forecast across northern MA today. So expecting low clouds
and fog to lift across the interior but then may redevelop later
today as showers become more widespread.
Bands of rain showers across the interior...mainly west of the
I-95 corridor. These showers will exit northward into central New
England. However a new area of showers just south of the islands
will come onshore early this afternoon from south to north. More
importantly is area of convection farther offshore south of New
England...which appears to be expanding with time per latest
satellite imagery. This area is associated with moisture
streaming north of a subtropical low north of the bahamas.
Complexity to our forecast is the exact track of this convection
this afternoon. Consensus from the 00z global guidance including
much of the mesoscale guid including the NMM/HRRR and RAP is for
this convection to move across RI and eastern MA. However some of
the mesoscale guidance including the 00z ARW and NCAR ensembles is
to track offshore convection farther west into CT and central MA.
Will need to evaluate 12z guidance and latest satellite and radar
trends before we have a better handle. Thus no major changes to
previous forecast. Earlier discussion below.
===================================================================
Previous discussion...
Amplifying mid level trof moving into the Great Lakes will back
the flow across the NE which will slow the eastward progress of
the frontal boundary in New York state, while allowing subtropical
low to lift north toward New Eng. One area of heavy rainfall will
persist to the west assocd with the slow moving front and right
entrance region of the upper jet. A second area of heavier
rainfall with the subtropical low and high PWAT plume is likely
but location is still somewhat uncertain. Guidance is favoring RI
and eastern MA during the afternoon as area of strong omega lifts
north from the ocean with anomalous PWAT plume focused across SE
New Eng, but it still could be further west per some of the hi-res
guidance. The other factor to consider is the airmass will
destabilize this afternoon with SBCAPES around 500 J/kg and
strong deep layer shear which may lead to isold strong t-storms
developing. The hi-res guidance is indicating potential for
localized heavy rainfall of up to 3 inches but low confidence on
location if this occurs.
Warm front lifts to the north with SNE in the warm sector today.
Temps will warm into the upper 60s to lower 70s and it will be
quite humid with dewpoints in the mid 60s.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Tonight...
Localized heavy rainfall with thunder potential will linger into
the evening as the sub-tropical low lifts north across the
region, then models are signaling a dry slot moving into the
region during the second half of the night. Expect precip to taper
off with areas of drizzle and fog developing overnight. Very mild
and humid into the overnight with temps holding into the 60s, then
falling through the 50s western New Eng late tonight as cold front
approaches from the west. Temps may remain in the 60s all night in
eastern New Eng.
Saturday...
Potent neg tilt trof and mid level low over PA will lift NE into
New Eng during Sat. Strong QG forcing and mid level frontogenesis
with deep moisture moving into SNE will lead to sct to numerous
showers on Sat, especially western New Eng. High temps will occur
in the morning with 50s west and 60s east, then falling into the
40s and 50s in the afternoon as strong cold advection develops.
Strong winds will develop in the afternoon as the low pres deepens
across northern New Eng with strong pres gradient and strong cold
advection developing. Potential for westerly gusts up to 40 mph
by mid/late afternoon and up to 50 mph for Cape/Islands. Wind
advisories will likely be needed for portions of SNE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Highlights...
* Some rain lingers int Saturday night, along with strong winds.
* Cooler and dry by Sunday.
* Seasonably cool early next week.
Overview and model preferences... The reasonably good agreement that
models have shown for much of the mid and extended terms continue
again with the overnight 00Z update. Only toward the end of next
week, with a deepening clipper, do they begin to show more extreme
differences at the synoptic scale. Deep trof/cutoff slowly shifting
into Atlantic Canada suggests seasonably cooler conditions to follow
the rain/unsettled wx ending by Sat night. These conditions linger
into mid week thanks to a persistent draw of CP air out of central
Canada. Not entirely dry, as weak reinforcing shortwaves could
deliver a few shra on Mon, but definitely more fall like until the
latter portions of next week. Update will feature a blend of
operational guidance as well as persistence.
Details...
Sat night... Low pres will continue to rapidly deepening as it
shifts into N New England and QC, possibility dipping into the 970s.
Very pronounced trowal/comma head setup wrapping well to the S and W
of this low as the upper lvl cutoff lags the sfc low. Good lapse
rates above developing inversion will enhance the precip efficiency
in this region as well. Therefore, could see some fairly persistent
wrap-around precip lingering into the overnight hours Sat. While
the highest risk will be in the upslope regions of the Berkshires
could see some of it spill across the CT valley and into the
Worcester hills as well. Only eastern areas will begin to see an
end to the precipitation thanks to good downslope component with W-
NW flow. Dry air begins to entrain, so expect rapidly dropping
dwpts into the early morning hours on Sun. Mins are likely to hold
in the 40s and low 50s however, mainly due to delayed cold advection
and remnant cloud cover lingering beneath dry inversion aloft.
Also, may need to watch for strong W-NW flow as strong isallobaric
couplet forms overnight. LLJ is near 45 kt at H92 to as well.
Mixing overnight could see yield winds to 40 kt at least, therefore,
may need to have a wind advisory into Sun morning.
Sun and Sun night... Gradual improvement as the downsloping and
drier air aloft is able to finally force some of the moisture in the
low levels out allowing for some clearing. Winds remain a factor,
although may drop below wind advisory criteria by late morning,
expect mainly 25-35 mph out of the W through the daylight hours. H92
temps hover around +3C so expect highs in the 50s, while mins drop
into the 40s (held back by the continued pres gradient).
Mon and Mon night... Secondary shortwave rotates through the trof to
the NE, reinforcing the cyclonic flow briefly. Noting enough
moisture between the sfc and H7 for there to be a few shra during
the day with this passage, enhanced by additional mid lvl cold
advection. Flow gradually shifts from predominantly W, to the NW
after this frontal passage. Similar temps to Sun as the strongest
cold advection lags into the overnight hours.
Tue into Wed night... Definite return to cool fall conditions. H92
temps drop as low as -1C by early Wed morning (H85 as low as -6C).
Winds remain elevated Tue, but shift gradually to the N-NW with
gusts 20-30 mph. The winds weaken Tue night into Wed as high pres
crests over the region. Therefore, highs in the upper 40s and low
50s are likely each day, with overnight mins dropping to near or
below freezing across much of the region thanks to radiational
cooling.
Thu into Fri... Clipper system approaches from the W, however there
is uncertainty on the final track. GFS is to the S, leading to S
New England lying on the climatologically dry N tier. The ECMWF is
stronger and to the N, suggesting a more unsettled/wet passage. In
any case, will be including some POPs for the tail end of the
extended forecast.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
1030 am update...
Brief improvement to VFR across RI and southeast MA...possibly
into northeast MA but then likely trending back to MVFR and
eventually IFR/LIFR after 21z-22z. Across CT and central-western
MA upward trends will continue for this afternoon but then back
down to IFR/LIFR this evening.
Short Term /through Saturday/...
Today...High confidence on trends but lower confidence on exact
timing and details.
LIFR/IFR will continue across most sites through 15-18Z with some
areas lifting to higher IFR/MVFR through the afternoon. Mostly fog
this morning, but higher risk for showers and even a few
thunderstorms this afternoon, heavier/steadier rain arrives this
evening especially for E MA and RI.
Tonight...High confidence.
More IFR/LIFR likely in showers/drizzle and fog. Isold t-storm
possible.
Saturday...Moderate confidence. IFR/LIFR improving to MVFR with
pockets of VFR cigs possible in the afternoon. Improving vsbys.
Sct to numerous showers, especially west. Winds becoming W with
gusts 30-40 kt developing in the afternoon.
KBOS TAF...High confidence in trends.
KBDL TAF...High confidence in trends.
Outlook /Saturday Night through Tuesday/...
Sat night into early Sun...High confidence.
Lingering IFR/MVFR conditions persist even as rainfall gradually
recedes across the east but continues across the west. Lower CIGS
will be the primary cause of the lower categories. Other issue is
winds, gusts 30-40 kt possible at times out of the W, sustained 20-
30 kt. Winds off the deck remain high as well 40-50 kt at about
2000ft.
Sun into Tue...High confidence.
Fairly persistent weather for the period. W winds continue 15-20 kt
sustained with gusts 25-35 kt at times, diminishing by late Tue.
Mainly VFR. Although some low clouds during the day light hours may
come close to the upper end of MVFR.
&&
.MARINE...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
1030 am update...not much change from previous forecast. Heavy
showers with embedded thunder likely late this afternoon and
evening across the eastern MA waters...possibly westward into RI.
Short Term /through Saturday/...Moderate confidence.
Today...Mainly SE gusts to 20 kt as warm front lifts north of the
region. Low vsbys in areas of dense fog will improve somewhat
toward midday. Potential for locally heavy rainfall, especially
this afternoon.
Tonight...As center of low pres moves across the waters easterly
winds will diminish then become SW/W toward daybreak as the low
moves to the north. Vsby reduced at times in areas of rain and
fog.
Saturday...Gale force SW/W winds developing in the afternoon with
gusts 35-45 kt. Gale warnings issued.
Outlook /Saturday Night through Tuesday/...
Sun night into Mon night...High confidence.
W wind gusts continue, reaching 35-45 kt while staying sustained 25-
35 kt. Gale warnings are likely to continue through this entire
period. Seas reach 10-12 ft on the ocean waters.
Mon into Tue...High confidence.
W winds continue, although they will gradually shift to the NW late
Mon into Tue. Gusts reach 25-35 kt. Small craft advisories will
follow the Gales. Seas slowly diminish through the period, but
should remain between 5-8ft through much of the period on the ocean
waters.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Gale Warning from noon Saturday to 8 AM EDT Sunday for
ANZ231>235-237-250-251-254>256.
Gale Warning from 2 PM Saturday to 8 AM EDT Sunday for ANZ230-
236.
&&
$$
SYNOPSIS...KJC/Doody
NEAR TERM...KJC/Nocera/Doody
SHORT TERM...KJC
LONG TERM...Doody
AVIATION...KJC/Nocera/Doody
MARINE...KJC/Nocera/Doody
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
626 AM CDT Fri Oct 21 2016
.DISCUSSION...Showers continue to move steadily southward with the
front which is well south of the Rio Grande. Latest HRRR has
trended with all showers remaining south of the river this
morning so have decided to drop the mention of the showers. Will
hang on to the clouds with slow clearing in the Valley.
Temperatures will be tricky with not much cold air advection
developing as of this time so confidence is low for the RGV to
see only the lower 80s. zones out soon.
&&
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...The cold front along with showers and thunderstorms
are well south of the three regional airports. Any MVFR cigs will
be right along the Rio Grande River for the next few hours with
general VFR conditions anticipated for all areas the rest of the
day. VFR cigs will be slow to erode especially across the south
with drier air mixing to the surface and breaking up the overcast
this afternoon. Stronger north-northwest winds gusting 20-25
knots, mainly near the coast, to gradually become north-northeast
this evening and lower considerably.
&&
.PREV DISCUSSION... /issued 452 AM CDT Fri Oct 21 2016/
SHORT TERM (Today through Saturday):
Finally the cold front has passed through Deep South Texas and is
currently clearing the mouth of Rio Grande. The front is losing
some of its punch as the mid level trough over the central
portions of the country quickly moves east but, high pressure will
be building southward allowing for a fresh northerly wind and
drier and cooler air to overspread the CWA as expected. No more
100 degree days (this week) at Mcallen, that makes 90 so far this
year, with at least a 15 to 20 degree cool down in the west and 10
degrees in the east. Scattered showers and isolated thunderstorms
along the leading edge of the front will continue to drift south
with front with only a small chance of additional rain across the
lower valley this morning. Models continue to indicated the
baroclinic zone in the vicinity of the lower valley maintaining a
slight chance of rain through at least mid morning and a slow
clearing of clouds this afternoon.
Surface ridging makes its farthest southern approach spreading along
the coastal bend and the coastal plains tonight before tracking east
Saturday. Clear skies and light northerly winds most locations
tonight allow temperatures to drop into the 50s most locations with
lower 60s across the Lower Valley and along the immediate coast
as some patchy cloudiness and slightly higher winds hang in.
As mentioned surface ridge shifts east with surface winds already
returning from the east by the afternoon. Drier air aloft to mix
through any remaining surface moisture with a fairly dry and clear
and mild day after the nice cool morning. One concern is across the
Lower Valley where the NAM, more than the GFS, show an increase in
low level moisture which might lead to increasing clouds in the
afternoon. Confidence in an mostly cloudy afternoon is low so will
continue with mostly sunny to partly cloudy.
LONG TERM (Saturday Night through Thursday): Surface ridge
continues to sweep off into the southeastern us over the weekend,
with southeasterly flow returning by Sunday morning. Best moisture
reaches region Monday and Tuesday, in decent timing with the
adjustment of the H5 ridge aloft out of the region. Will continue
to indicate a small chance for showers Monday and Tuesday, but
chances remain thin with the lack of a substantial surface forcing
mechanism. By Wednesday, the next upper ridge shifts into the
region from the west, introducing more dry air aloft and
increasing subsidence. The latter half of the week will be similar
to earlier this week, with ample moisture trapped in the lowest
few thousand feet. This will bring daytime CU field through the
afternoons, with a minimal chance for a shower or two if the
seabreeze can get organized enough. Otherwise temperatures will
remain slightly above normal, reaching the upper 80s to lower 90s
each afternoon, while lows fall into the upper 60s to around 70.
MARINE:
Now through Friday: Winds are peaking this morning as the
pressure gradient is reaching its peak behind the front. Seas will
continue to build also peaking by mid morning. As high pressure
builds along the coastal bend by this evening a gradual lowering
of the northerly winds is expected. Small craft advisory
conditions persist much of the day with winds lowering over the
Laguna around mid day and offshore this evening. Higher seas may
linger through the overnight period with a possible extension of
the SCA. Much improved conditions Saturday as high pressure
spreads east and weakens.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 79 64 83 70 / 10 0 0 10
BROWNSVILLE 81 63 85 68 / 10 0 0 10
HARLINGEN 81 58 84 65 / 10 0 0 10
MCALLEN 82 59 87 66 / 10 0 0 10
RIO GRANDE CITY 82 56 86 64 / 10 0 0 0
SOUTH PADRE ISLAND 80 70 82 73 / 10 0 0 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 4 PM CDT this afternoon for
GMZ130-132-135.
Small Craft Advisory until 7 PM CDT this evening for GMZ150-155-
170-175.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
59...short term
64...long term
Area Forecast Discussion
National Weather Service Goodland KS
830 AM MDT Fri Oct 21 2016
.UPDATE...
Issued at 830 AM MDT Fri Oct 21 2016
Have updated the forecast the remove frost and cancel the frost
advisory. Latest obs from around the affected areas showing upper
30s to the lower 40s. Rest of the forecast unchanged as CWA will
see filtered sunshine and highs in the lower to mid 70s.
&&
.SHORT TERM...(Today through Sunday night)
Issued at 202 AM MDT Fri Oct 21 2016
Early morning WV imagery and RAP analysis shows large scale
ridging building across the western US into the plains, with NW
flow over the Central High Plains. At the surface, high pressure
has slid east of our CWa towards the southern Missouri River
valley. Lee trough has redeveloped and southerly surface gradient
is in place over our CWA.
Regarding frost advisory this morning: Temps have already dropped
to low to mid 30s at multiple locations across our CWA (upper
bound of, which is already faster than the forecast diurnal curve
indicated. Southerly winds 10-15 mph are leading to better
mixing/higher temps elsewhere, but further decoupling should
result in a gradual decrease in winds by sunset. There is still
enough time for winds to drop off and temps to quickly fall to the
lower 30s across our entire CWA due to mostly clear skies and Tds
in the 20s to lower 30s. Will keep frost advisory in place as it
is, and let it run it`s course as frost conditions are still
likely through the morning.
Today-Sunday night: Mid to upper level ridging across the southern
US will dominate sensible weather. A very deep dry air mass will
remain in place, with cross mountain flow along northern part of
ridge. A shortwave trough rotating through the Northern Plains
near the US/Canada border, and it`s associated (weak) cold front
will drop south Saturday night. Despite periods of weak forcing
the dry/stable air mass will preclude any precipitation chances.
Above normal temperatures are expected through these periods with
the warmest day on Saturday when highs will reach the lower 80s
for parts of our CWA.
.LONG TERM...(Monday through Thursday)
Issued at 202 AM MDT Fri Oct 21 2016
Predominantly dry weather continues during the extended period
with above normal high temperatures in the 70s. Low temperatures
start off in the 40s to low 50s before decreasing into the upper
30s to mid 40s.
On Monday, the upper ridge dominating the pattern progresses east
of the region, keeping conditions dry. However, the ridge breaks
down on Tuesday as a stronger disturbance passes through the
southwesterly flow. This generates precipitation chances for the
central Plains. At this time, it appears the better chance for
precipitation will be east of the region, with only a slight
chance of showers and thunderstorms clipping the extreme eastern
portion of the forecast area Tuesday afternoon and evening. After
this brief opportunity for some rain, the ridge rebuilds over the
region, bringing near zero PoPs back to the forecast on Wednesday
and Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 513 AM MDT Fri Oct 21 2016
VFR conditions will continue at KGLD and KMCK terminals through
the TAF period. KGLD ob showing vis 3SM HZ this morning is due to
faulty sensor (spider webs). Conditions are clear with no vis
restriction. There will be brief period of low level wind shear
at KMCK this morning as a LLJ transitions eastward across the
region. Prevailing winds should remain below 12kt through the TAF
period.
&&
.FIRE WEATHER...
Issued at 202 AM MDT Fri Oct 21 2016
Very dry air mass and above normal temperatures will lead to
afternoon RH values dropping to 15 percent or lower for parts of
our CWA. Daytime winds are not expected to reach or exceed
critical criteria. We could have a few brief periods of 20 mph
gusts midday Saturday, but this would likely occur while RH values
are still 20 percent or higher. Critical fire weather conditions
are not expected at this time.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JN
SHORT TERM...DR
LONG TERM...JBH
AVIATION...DR
FIRE WEATHER...DR
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1034 AM EDT Fri Oct 21 2016
.SYNOPSIS...
A cold front will cross the area this morning, ushering in a much
cooler and drier air mass for the weekend. Another cold front will
cross the region on Monday to reinforce the cooler temperatures.
After that front passes, high pressure will control our weather
through the middle of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1030 am: The HRRR and NAM12 show a pressure kink in the lee of
the mtns, suggesting a mtn wave will remain through most of daylight
hours. Latest vis sate loop shows some wave clouds over the adjacent
foothills from Caldwell south to Polk Co. Given daytime mixing and
support from a 6-7 mb pressure gradient across the mtns, I have
highlighted the gust winds with a Wind Advisory across the east
facing slopes and adjacent NC foothills hills through 6 PM.
Grandfather Mtn., with a high elevation site, had a gust to 65mph
last observation. Otherwise, a shallow cloud deck exist across
middle and eastern KY/TN under deep dry air. Moist llvl NW flow
should support iso to sct showers along the TN/NC line through much
of the day. Otherwise, the region will remain dry and cool.
630 am update: the cold front has been steadily pushing eastward
across the NC mts early this morning accompanied by scattered rain
showers. Winds are just now starting to veer around to NWLY over
far western NC and increase in speed. Otherwise, the fcst is still
pretty much on track for the rest of today and tonight.
As of 320 am Friday: precip has been fairly slow making its way
into the CWFA early this morning. So far, it has been confined
to the NC/TENN border zones. Cloud cover should continue to
increase thru the morning hours as the cold front pushes farther
east. Overall, the most recent model guidance is trending drier
with this fropa. Likely to categorical POPs are confined to the
NC/TENN border counties with slight to solid chance elsewhere.
By 00z Saturday, drier air will be advecting into the CWFA behind
the front and POPs dwindle. Winds will be gusty today and are
expected to remain out of the NW and blustery, especially over
the higher terrain, well into Saturday. By midday today, wind gusts
are expected to reach the upper 30s kts across the high terrain
and east facing mtn slopes. The strongest gusts will likely occur in
the wake of the mtns, with the forecast development of a mtn wave.
Based on the latest model guidance, I`ve lowered wind speeds a bit
from the previous fcst. Thus a Wind Advisory should not be needed,
however we will monitor trends if the guidance trends upward.
Otherwise, temps will be considerably cooler today and tonight with
highs and lows nearly 20 degrees cooler than yesterday.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 230 AM EDT Friday...the balance of the weekend looks cool and
relatively quiet, although Saturday should be a bit breezy. Think
any lingering small chance of precip will not linger past the middle
part of Saturday morning...thereafter sky will gradually clear
across the NC mtns. The main story will be the high temps...which
will be on the order of 7-10 degrees below normal...under a mostly
sunny to sunny sky. This will finally make it really feel like
Autumn across the region at long last.
The axis of the upper ridge will remain to our west through the rest
of the weekend, which will keep the wrn Carolinas under a cool NW
flow, and will support surface high pressure moving across the
Southeast. This should yield another seasonally cool night on
Saturday night with temps getting cold enough for more widespread
frost across the mtns once the wind dies down toward daybreak on
Sunday. There could even be some patchy frost outside the mtns in
the normally cooler and sheltered spots. Temps will moderate quickly
on Sunday afternoon...returning to near normal under sunny sky...and
will not be nearly as cold Sunday night ahead of a reinforcing cold
front dropping down from the NW.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 245 AM EDT Friday...not much change in thinking with regard to
the medium range. A reinforcing cold front will move through early
Monday, bringing in another high pressure air mass from the NW. The
timing of the frontal passage will have a big affect on the high
temp fcst that day, which at present remains above normal. This
could easily get knocked back several degrees if the front arrives
Sunday night. Either way, temps will be closer to normal thru
mid-week as surface high pressure moves past to the north.
Confidence slowly erodes through the end of the week as the model
guidance shows the next system moving across the Gt Lakes on
Thursday and pushing a cold front toward our region. There remains
consensus among the operational model solutions that the front will
dry up before arrival, so the fcst was kept dry. This might be more
bad news for people that need rain, but is not atypical of October
across the region.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: the cold front continues to push eastward
across the NC mts early this morning. A band of light showers
remain confined to the higher terrain, but should spread into the
foothills over the next few hours. The only restrictions included
for TAF period are MVFR cigs at KAVL from roughly 13z thru late
tonight and the possibility of visby restrictions if the site receives
much precip. Persistent gusty winds along and behind the cold front
will be the main concern for the period. Winds will veer around to NWLY
later this morning and remain NWLY for for the remainder of the period.
Speeds will be highest over the higher terrain include KAVL with sustained
speeds in the 15 to 20kt range and gusts around 25kts with some brief
higher gusts likely. The other sites should see slightly weaker values.
Outlook: the pressure gradient will remain tight across the western
Carolinas through Saturday with breezy conditions expected. Dry high
pressure will then spread across the region on Sunday and linger into
early next week.
Confidence Table...
14-20Z 20-02Z 02-08Z 08-12Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL Med 78% High 100% High 100% High 100%
KHKY High 100% High 100% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Wind Advisory until 6 PM EDT this evening for NCZ033-049-050-
053-065-501-503-505-507-509.
SC...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...NED
SHORT TERM...PM
LONG TERM...PM
AVIATION...JPT
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1038 AM EDT Fri Oct 21 2016
.SYNOPSIS...
A cold front will pass through the region today. An upper-level
trough will pass through the area Saturday and high pressure will
build into the region for Sunday. A reinforcing cold front will
pass through the area Monday with high pressure returning for the
middle portion of next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
The cold front is pushing through the Highlands as of mid-morning.
Narrow band of low topped convection is accompanying the front,
with a few gusts of 30-40 MPH observed. HRRR continue to shows
lightning possible as the line pushes east of the Blue Ridge this
afternoon, although poor lapse rates above 15kft should limit both
lightning and any potential of severe-level wind gusts. Morning
update largely focused in refreshing timing of all elements as the
front passes. Otherwise, the previous thinking is largely on
track. POPs have been tapered more slowly this evening due to the
HRRR/RAP showing better shower potential with the vort max. We
may need to consider both wind and freeze products for the
Highlands tonight.
Previous discussion:
The cold front will make its way through the Washington and
Baltimore Metropolitan areas between 1 and 4 pm this afternoon.
The cold front will pass through the Bay late this afternoon.
Showers are likely along and just ahead of the boundary as it
moves through the area. More showers are possible behind the cold
front as a potent upper-level disturbance pass through the region.
Confidence in max temp forecast is low since it will be highly
dependent on the timing of the frontal passage. Max temps are
forecast to range from the mid to upper 50s in the Allegheny
Highlands...to the upper 60s and lower 70s for valley locations
west of the Blue Ridge Mountains...to the upper 70s and lower 80s
near Washington and Baltimore into southern Maryland. Temperatures
are expected to drop quickly behind the cold front...into the 40s
and 50s this afternoon west of the Blue Ridge Mountains and into
the 50s and 60s east of the Blue Ridge Mountains by late this
afternoon.
The cold front will move off to the east this evening and the
upper-level disturbance associated with the boundary will pass
through during this time. Blustery northwest winds are also
expected behind the front and this will cause temperatures to
continue falling. A few showers are possible due to the passing of
the upper-level disturbance...but precipitation amounts will be
light.
The upper-level disturbance will develop into a closed upper-level
low overnight and the upper-level trough overhead will shift to a
negative tilt. This will cause surface low pressure to rapidly
intensify off to our north and east. A strengthening pressure
gradient will cause gusty northwest winds overnight. Wind gusts
around 50 mph are possible along the ridges of the Allegheny and
Potomac Highlands as well as the Blue Ridge and Catoctin
Mountains. A wind advisory may be needed for these areas.
Elsewhere...frequent gusts around 30 mph are expected. The
northwest flow will dry things out across most areas...but a few
rain/snow showers are possible along the ridge tops along and west
of the Allegheny Front. Snow may coat grassy surfaces above 3kft.
A freeze is possible overnight across the ridge tops of the
Allegheny and Potomac Highlands...mainly above 3kft.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Low pressure will continue to intensify as it tracks northward
into Ontario Saturday. High pressure will remain over the MIdwest
into the Gulf Coast States. A tight gradient between the departing
low and the building high will continue to cause windy conditions.
Cold advection will increase mixing...so wind gusts around 35 to
45 mph are expected. A wind advisory may be needed for portions of
the area. The best chance for wind gusts around 50 mph will be
along the ridges. Max temps Saturday will be much chillier due to
the northwest flow...ranging from the 40s in the mountains to the
upper 50s and lower 60s near Washington and Baltimore into
southern Maryland.
High pressure will build to our south Saturday night through
Sunday. Breezy conditions along with mainly clear skies are
expected. Sunday may be a bit milder due to a downsloping westerly
flow with highs in the 60s across most areas. A reinforcing cold
front will approach Sunday night...but it should remain to our
north. More dry and seasonable conditions are expected.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
A reinforcing cold front will cross the area on Monday. GFS/ECMWF
timing differ a bit. Splitting the difference suggests it may be a
morning fropa. Although moisture and upper level energy remain to
the northeast of the forecast area, nearer the lower heights in the
base of the trough axis, cold advection will sweep the area during
the day. As a result, the frontal passage should be dry, with
perhaps a few more clouds. After that, expect mostly sunny and
breezy conditions.
It may be difficult to get frost Monday night due to a breeze
(there`s still room for that to change), but temperatures should
drop into the 30s in the mountains, lower-mid 40s elsewhere. After a
day in the mid 50s-lower 60s Tuesday, radiational cooling should be
better Tuesday night as the center of high pressure builds toward
the Mid Atlantic. This may spell the end of the growing season for
outlying/rural areas.
The next storm system will be cutting across the Ohio Valley toward
the Great Lakes toward midweek. While is should stay north/west of
the area, its attendant cold front will approach by Thursday,
potentially bringing showers back to the area.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
A southerly flow will continue to ahead of a cold front through
this morning. Narrow band of MVFR/IFR cigs east of the Blue Ridge
is beginning to break up per visible satellite. However, low
confidence on whether this deck fully lifts before fropa.
A cold front will pass through the terminals...across KMRB
before noon...then across the rest of the terminals between 1 pm
and 4 pm. A wind shift to the northwest is expected behind the
front with gusts around 20 to 25 knots likely. A narrow line of
showers also may produce gusts of 30 kt and isolated lightning
east of the Blue Ridge. Showers may hang around into this evening
as an upper-level disturbance passes through. MVFR conditions are
possible in showers today.
Gusty northwest winds will continue through Saturday evening. The
highest gusts are expected Saturday when mixing will be strongest.
Gusts around 35 knots are likely. Winds will diminish Saturday
night...but breezy conditions will continue through Sunday as high
pressure settles to the south.
VFR conditions should prevail Monday-Tuesday. Could have some gusty
northwest winds on Monday behind a cold front.
&&
.MARINE...
A southerly flow will continue through early this afternoon ahead
of a cold front. Will continue with the Small Craft Advisory...but
it will be marginal. The cold front will pass through the waters
between 2 and 5 pm this afternoon. A wind shift to the northwest
is expected behind the boundary and winds will become gusty. A
line of showers will accompany the front. While most wind gusts
should be 20-30 kt, can`t rule out higher gusts, especially if
thunder is able to develop. Since the synoptic gale isn`t expected
until much later, these showers/storms could require Special
Marine Warnings.
Winds will increase as the pressure gradient strengthens tonight
through Saturday. A Gale Warning is in effect for the Bay and
lower tidal Potomac River tonight...and for all the waters
Saturday. The strongest winds are expected Saturday. Winds will
diminish a bit Saturday night...but a Small Craft Advisory will
likely be needed. More breezy conditions are expected Sunday into
Sunday night.
A cold front will cross the waters on Monday. Small Craft
Advisories seem likely from this vantage point behind the cold
front. Winds will be diminishing on Tuesday as the pressure
gradient relaxes.
&&
.TIDES/COASTAL FLOODING...
A south to southeast flow has caused tidal anomalies to increase
quickly this morning. Anomalies are still increasing to around 1
to 1.5 feet above normal this morning as the south to southeast
flow continues. A Coastal Flood Advisory is in effect for Anne
Arundel County with the current high tide. Minor flooding is
possible around high tide early this afternoon near Washington DC.
Will have to monitor anomalies this morning. South to southeast
winds will continue through early this afternoon before turning
quickly to the northwest by the end of the day. Minor flooding is
possible during the high tide cycle late this afternoon into this
evening...but confidence is low because of the northwest flow that
will be developing during this time.
Anomalies will drop sharply tonight and blowout tides are possible
for Saturday due to a strong northwest flow.
&&
.CLIMATE...
Record high minimum temperatures were set at DCA...BWI...and IAD
Thursday...October 20th. See the latest RER for more details. The
passage of a cold front should prevent records from being reached
once again today.
Records for Oct 21st...
DCA...High 85 in 1947...warm low 64 in 1984.
BWI...High 90 in 1947...warm low 63 in 1947.
IAD...High 86 in 1979...warm low 60 in 1979.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Coastal Flood Advisory until noon EDT today for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for
ANZ530>534-537>543.
Gale Warning from 6 PM this evening to 6 PM EDT Saturday for
ANZ530>534-537>543.
Small Craft Advisory until 6 AM EDT Saturday for ANZ535.
Gale Warning from 6 AM to 6 PM EDT Saturday for ANZ535-536.
Small Craft Advisory until 6 AM EDT Saturday for ANZ536.
&&
$$
SYNOPSIS...BJL
NEAR TERM...BJL/ADS
SHORT TERM...BJL
LONG TERM...HTS
AVIATION...BJL/ADS/HTS
MARINE...BJL/ADS/HTS
TIDES/COASTAL FLOODING...BJL/ADS
CLIMATE...HTS
Area Forecast Discussion
National Weather Service Raleigh NC
1050 AM EDT FRI OCT 21 2016
.SYNOPSIS...
An amplifying upper level trough and attendant cold front will track
east across the Carolinas today. A cooler and drier airmass will
advect into the region from the northwest in the wake of the
front tonight and Saturday.
&&
.NEAR TERM /TODAY AND TONIGHT/...
As of 1050 AM Friday...
Despite an impressive water vapor signature associated with the deep
upper wave crossing the Ohio/Tenn Valley, there is very little
precip on radar south of Roanoke VA, owing mainly to a lack of deep
moisture with PW at one inch or less. Still, with 170m height falls
at BNA this morning and intense FGEN showing up from 925mb through
700mb, there should be sufficient forcing to spark a band of showers
this afternoon. Latest HRRR runs have shown a small decrease in the
coverage of showers that develop along the cold front, which
currently extends through western VA to just west of the Triad, as
it approaches US 1 around 18Z and I-95 by 21Z. Given the amount of
dry air, the environment will be supportive of some 25-35kt wind
gusts through dry air entrainment and DCAPE increasing to around
800J/KG across the south, but this conditioned on whether or not any
deeper convection can develop without any appreciable instability,
which RAP forecast soundings don`t show much support for.
Changes to the forecast this morning as minor, mainly to reduce POPs
in the west this morning based on radar trends and adjust temps to
the lack of early precip. Have also nudged up sky cover in the
west with the slowly burning off of fog. Highs should still end up in
the upper 60s to upper 70s, with temps starting to fall by mid
afternoon the west.
-BS
Expect rapid clearing from west-east 3-6 hrs after the cold frontal
passage at any given location, with clear skies and a NW breeze
prevailing tonight. Lows Saturday morning will be driven by both
cold advection and radiational cooling, ranging from the low/mid 40s
N/NW to mid/upper 40s S/SE. -Vincent
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 300 AM Friday...
Cool, clear and breezy today due to cold advection in the wake of an
amplifying upper level wave tracking offshore the Carolina/Mid-
Atlantic coast tonight and Saturday. Expect clear skies and a breezy
NW wind with highs in the upper 50s to lower 60s, coolest NW
Piedmont. Chilly lows sat night in the lower 40s. -Vincent
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 315 AM Friday...
Dry and seasonably cool weather is expected from Sunday through mid
week. Gradually rising heights as high pressure builds in from the
south will provide us with a short-lived warming trend Sunday and
Monday, with highs warming to the mid and upper 60s Sunday, and
further into the low and mid 70s on Monday.
A reinforcing shot of dry and cooler air is expected as a cold front
moves south and through the area on Monday. This airmass will be
locked into place through the midweek as high pressure builds south
down the Atlantic coast. Highs Tuesday through Thursday will be
mostly 65 to 70 after morning lows mostly in the mid 40s.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
As of 600 AM Friday...
24-hr TAF Period: IFR/LIFR visbys in fog or low stratus will affect
eastern terminals (FAY/RWI/RDU) through 12-14Z before dissipating.
Shower activity and borderline MVFR/VFR ceilings are expected at all
terminals today as a cold front tracks east across central NC.
Expect the best chance for showers between 12-17Z at the INT/GSO
terminals, 16-21Z at the RDU/FAY terminals, and 17-22Z at the RWI
terminal. Southwesterly winds at ~10 kt will prevail in advance of
the cold front, shifting rapidly to the NW at 10-15 kt sustained
gusting 20-25 knots for 1-3 hours in the wake of the front. Somewhat
stronger winds will be possible at eastern terminals where fropa
timing will better coincide with peak heating.
VFR conditions will rapidly return in the wake of the front,
earliest at INT/GSO (this afternoon) and latest at RWI (this
evening).
Looking Ahead: Breezy NW winds will persist into Sat, sustained at
10-15 kt with gusts up to 20-25 kt, becoming westerly and weakening
on Sunday. VFR conditions are expected to rule for the remainder of
the weekend and through the majority of next week. -Vincent
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Vincent
NEAR TERM...Vincent/BS
SHORT TERM...Vincent
LONG TERM...MLM
AVIATION...Vincent
Area Forecast Discussion
National Weather Service State College PA
540 PM EDT Fri Oct 21 2016
.SYNOPSIS...
A wavy cold front will move east of the area this evening,
followed by windy and showery conditions for tonight through
Saturday night. The first bout of lake effect and upslope rain
and snow showers are possible over some of the higher ridge tops.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The cold front is entering the lower Susq Valley as of 2 PM with
a broken line of heavy gusty showers. The more spotty and less
organized lighter rains continue to feed north behind the the
front ahead of the approaching upper trough. The HRRR keeps the
off an on rain going this evening before finally beginning to wind
down for the second half of the overnight. Existing flooding
issues are reportedly beginning to improve so most of the flood
watch has been canceled.
Something to consider for later tonight into early Saturday will
be the potential for the season`s first accumulating snows over
the RIDGETOPS of the Laurels and Northern Mountains. The guidance
has been persistent in bringing the coldest 850mb temps of the
season to date in behind our deep upper low. The potential for a
light slushy inch over the ridges is shown in the HRRR and NCAR
ensemble. The deterministic NAM and GFS are showing chances for
light accums over larger more general areas of the west and north,
this seems too generous given surface temps will be relatively
warm. Am thinking we will try to emphasize a light slushy accum
over the higher elevations only.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
A cool and unsettled day is in store Saturday as persistent
northwest flow and progressively cooler boundary layer air is
forced into the region. In fact 850 mb temps remain
below 0 throughout the day throughout central PA...and we`ll
certainly be looking at a few wet snowflakes mixing in at times
with some of the showers over the higher terrain of the northwest
and northern mountains. Under scenarios such as what we expect,
the best chance for measurable precipitation usually favors these
western and northern higher terrain areas with little more than
sprinkles elsewhere.
Maxes will range from the lower 40s northwest to the lower to
middle 50s southeast.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
As the surface and mid level systems track through eastern Quebec,
a broad cyclonic/northwest flow pattern will continue into early
next week. Models forecast lingering deformation or lake-enhanced
pcpn to come to an end by early Sunday morning. Gusty winds will
should weaken a bit with peak gusts not as strong as Saturday.
Focus will shift upstream to a series of shortwaves diving
southeast from the Upper Midwest/Great Lakes through the Northern
Mid Atlantic region. Models show some varying QPF solutions with
these features, but with limited moisture look for max amounts in
the 0.10 to 0.25 range over north-central PA. Following a brief
moderation in sfc- 850mb temps on Sunday, the aforementioned
shortwaves will bring a reinforcing shot of chilly air into the
area with below normal temps forecast into the middle of next
week. High pressure should provide dry weather Tue-Wed with pcpn
probs increasing toward the end of the week, with GFS/EC models
and ensembles showing a low pressure system reaching the Great
Lakes/Ohio Valley by Thursday.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
Minor adjustments made to the 21Z TAF package.
Still some heavy showers across the far east for another few
hours.
Visibilities not bad, given fresh air moving in behind the
cold front. Main issue will be low clouds.
Earlier discussion below.
Widespread IFR/MVFR will continue behind the front today and
overnight as a slow moving cold front slides east across the
flying area. The wind will turn the NW behind and become gusty in
the 10-20kt range today.
Outlook...
Sun...No sig wx.
Mon...Mainly VFR. MVFR with rain showers possible NW.
Tue-Wed...No Sig Wx.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...La Corte
LONG TERM...Steinbugl
AVIATION...La Corte/Martin
Area Forecast Discussion
National Weather Service Green Bay WI
531 PM CDT FRI OCT 21 2016
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Saturday
Issued at 247 PM CDT Fri Oct 21 2016
The latest RAP analysis and satellite/radar imagery show a surface
ridge axis extending from north-central Ontario, across central WI
to central Texas early this afternoon. But despite the close
proximity of the surface high, a cold airmass and steep low level
lapse rates continues to lead to widespread low clouds, similar to
yesterday. Think this cloud cover will persist through the rest of
the afternoon, and likely into much of the evening over eastern WI.
Not out of the question that a spotty shower could occur over
Marinette and Door counties. Looking upstream, broken mid and high
clouds are pushing east over the northern Mississippi Valley in a
region of warm advection. A few weak returns are showing up over
eastern North Dakota and northern Minnesota. Forecast concerns
revolve around light precip chances and cloud trends.
Tonight...High pressure at the surface will be moving across the
region tonight. The high is not exactly clean however, so will keep
scattered wording over north-central WI into the evening. Otherwise,
think the broken cloud cover will persist over eastern WI through
much of the evening and possibly overnight over the Door. Deep upper
troughing will finally depart the area overnight, and the resultant
warm advection will bring a swath of broken mid and high clouds
across the area. The saturated layer is not really deep, so at best
think only a few sprinkles will be possible. Confidence is too low
for an inclusion of sprinkles into the forecast though, and will
leave the area dry instead. Lows mainly ranging from the mid 20s to
mid 30s.
Saturday...A layer of 5-6 kft clouds will shift east across the
region through the morning and into early afternoon with warm
advection lowering. The atmosphere becomes really dry above this
layer, so precip chances will be too small to mention. As the
clouds depart in the afternoon, should see the sun return along
with warmer temps. Highs in the mid to upper 50s.
.LONG TERM...Saturday Night Through Friday
Issued at 247 PM CDT Fri Oct 21 2016
Northwest flow will prevail into early next week, with generally
dry quiet weather expected. The main exception will be Sunday when
a mid level disturbance tracking through the northern Great Lakes
brings the chance for showers across the extreme northern cwa. The
next significant chance for widespread rain arrives during the
middle of next week as a low pressure system develops across the
central plains on Tuesday. This low will track to the south of the
area on Wednesday and Wednesday night, bringing rain to much of
the area. Being on the cold side of the system there could be a
few snowflakes mixed in with the rain at times Monday night and
Tuesday night across north-central Wisconsin, however the impact
is expected to be minimal. Although the low will be east of the
area late next week, additional shortwaves embedded in northwest
flow will bring a small chance for showers during this period.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 429 PM CDT Fri Oct 21 2016
As high pressure drifts slowly east tonight, a weak frontal
system will approach from the Northern Plains. A lower end VFR
clouds will linger over eastern Wisconsin tonight while mid to
high level clouds approach from the west. Little change in cloud
expected for saturday, with perhaps the higher end VFR clouds
become more dominate.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kurimski
AVIATION.......TDH
Area Forecast Discussion
National Weather Service Gray ME
533 PM EDT Fri Oct 21 2016
.SYNOPSIS...
A slow moving frontal boundary and a developing low pressure
center will bring wet weather and a cool onshore flow to the
region into Saturday. Later Saturday and Saturday night...the low
will gradually lift north into Quebec. On the backside of this
system...colder air will arrive on gusty northwest winds for the
latter part of the weekend and early next week. Some accumulating
snow will be possible in the mountains Saturday night into Sunday
night. A large Canadian high pressure system will then dominate
the region through midweek next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
530pm update... Main update at this time was to the PoP to more
closely reflect the radar returns showing rain pushing into
western new hampshire and keeping eastern sections lower.
Region of stronger convection /as seen by -60C IR cloud tops/ now
moving over the 70W/40N benchmark. Satellite trends and high res
guidance continues to point to it moving northwards into our area
around midnight. Heaviest rainfall would be from portland
eastwards to penobscot bay. While the rain looks to move through
relatively quickly, there is a slight chance for it to get hung
up along the coast which will need to be monitored.
Previous Discussion:
There are two main wx concerns for tonight...rnfl and fog.
For starters marine fog is already creeping back SWwd along the ME
coastline. Inland vsbys have improved slightly...but will trend
back down after dark and likely stay that way as low pressure
moves overhead. NARRE-TL hints at dense fog moving towards the
forecast area from the S after midnight...so at this point will
keep fog in the forecast and monitor for a potential dense fog
advisory.
Regarding the rnfl...the area to watch is developing S of Cape Cod
at this hour. A large area of convection continues to peel off of
the sub-tropical low pressure off the Carolinas...heading towards
New England. The low level moisture has already arrive across Srn
New England...with showers moving N thru the area. I have
increased PoP across Srn NH in the next couple of hours for these
showers. Satellite cloud patterns already suggest low pressure
circulation is developing within this convection...and model
guidance pivots this into Wrn ME this evening. Global guidance of
the GFS and ECMWF have finally come around to the idea of
potentially heavy rnfl along and E of the low pressure track. This
matches hi-res guidance like the HRRR and NCAR ensembles. Most
favorable area will be the border of NH and ME...and on Ewd thru
the night. Best period for potential heavy rnfl will be 00z to 06z
this evening...as the low level jet pivots NEwd.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Band of rnfl exits the forecast area early Sat...but with surface
trough overhead I do not expect much clearing. Stratus should
linger...and there may be drizzle in the early part of the day
with weak lift continuing in the dry slot.
Upper trof swings thru the region in the afternoon. An area of
showers is likely to be forced out ahead of this
feature...sweeping SW to NE across the forecast area in the
afternoon. It is near and after this time that winds will begin to
increase...especially as colder air filters into the area. Behind
the upper trof strong pressure rises may help to bring some gusty
winds...though that potential looks best across Srn New England.
As cold air deepens Sat night it is more likely that is when winds
begin to pick up across our forecast area. At this time it looks
to be a slow and gradual build up...before CAA really kicks in on
Sun. Snow levels will also be dropping Sat night...and some
accumulations are possible at the highest elevations late Sat. The
best shot is above 3000 feet...but elevations down to around 2000
feet may see some flakes as well. Winds and poor trajectory for
cold air delivery most likely keep the valleys well mixed enough
to preclude any snwfl.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Upcoming Potential Hazard: Strong, gusty winds on Sunday.
Winds align through a deep layer as a strong surface low (~980 mb)
exits into the Canadian Maritimes. The upper low shifts east of
New England as well, allowing for a deep, well mixed layer. Models
have shifted into agreement for the passage of the upper level
features. This passage, in combination with a strong gradient and
cold air advection will allow for very gusty winds Sunday. Wind
advisories may be needed as we continue to monitor the situation.
Wind gust over 45 mph would lead to scattered power outages.
Expect upslope rain showers to develop. Cold air advection and the
wet bulb affect will allow the rain showers to mix with and
change to snow showers at the higher elevations where a light
coating of snow is expected.
A short wave quickly races through the region Sunday evening,
bringing a reinforcing shot of cold air and continued very gusty
conditions along with moisture to the region.
The upper level low will remain over the Canadian Maritimes for
much of this upcoming work week. This will keep cool and breezy
conditions over the region as high pressure remains in control of
the Northeast.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
Short Term...Widespread LIFR conditions will continue thru
tonight. Some brief improvement to VFR and MVFR over parts of NH
will deteriorate again tonight as well. The low level jet lifting
over the region late this afternoon and evening will also yield
some marginal LLWS at the TAF sites. LIFR and IFR remains
widespread until late Sat when CAA will start to mix out the
wedged in low level air mass.
Long Term...Conditions will improve to VFR by Sunday morning
outside of the mountains, which will linger in MVFR to IFR briefly
in SHRA at KHIE through Sunday. Also look for NW winds of above
30+ kts on Sunday. VFR is expected at all terminals much of next
week.
&&
.MARINE...
Short Term...SCA conditions will continue into Sat...with brief
breaks in wind as low pressure center moves overhead. Eventually
CAA developing on the backside will increase winds to near gale
force on the outer waters late Sat.
Long Term...A period of gales is possible Sat night into Sunday
with winds diminishing a bit Sunday night into Monday morning.
Gale watches have been issued for the outer waters with borderline
gale conditions possible over the bays.
&&
.TIDES/COASTAL FLOODING...
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 8 PM EDT Saturday for ANZ150>154.
Gale Watch from Saturday evening through Sunday afternoon for
ANZ150-152-154.
&&
$$
SYNOPSIS...
NEAR TERM...Curtis
SHORT TERM...
LONG TERM...Cannon
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Lincoln IL
215 PM CDT FRI OCT 21 2016
.SHORT TERM...(This evening through Saturday)
ISSUED AT 215 PM CDT Fri Oct 21 2016
Sprawling ridge of high pressure currently extending from Ontario
to the Southern Plains will shift eastward across the area tonight,
providing mostly clear skies and light winds. The ridge axis will
be centered over the eastern KILX CWA by 12z Saturday, with some
light return flow developing further west across the Illinois River
Valley. As a result, am expecting the coldest overnight lows across
the E/NE counties near the Indiana border. Most model guidance
supports lows in the middle to upper 30s...and with dewpoints
currently ranging from the middle 30s west to the lower 40s east,
think these numbers look reasonable. Patchy frost will likely
develop overnight, especially east of the Illinois River where winds
will remain lightest. Given borderline temps in the middle to upper
30s and some high/thin clouds drifting overhead, do not think frost
will become widespread enough to warrant a Frost Advisory. Once the
ridge axis shifts further eastward, southerly return flow will bring
warmer air back into the area on Saturday. With south winds and
full sunshine, afternoon highs will reach the lower to middle 60s.
&&
.LONG TERM...(Saturday night through Friday)
ISSUED AT 215 PM CDT Fri Oct 21 2016
High pressure ridge will be east of the CWA Sat night and will
continue to move east Sunday, allowing southwesterly winds to return
to the area. In addition, a cold front will drop into the state from
the northwest and slowly slide through the CWA Sunday afternoon
through night. This front will come through dry since the
southwesterly flow will not bring any moisture back into the area.
Another high pressure area will drop into the state, but this one
will come from the Canadian area and will be cooler. This high
pressure will keep dry conditions in the CWA for Mon through
Tuesday. Then the next weather system and associated precip will
approach the area from the west. Showers and thunderstorms are
expected late Tue night through Wednesday as the cold front moves
into the area. Showers and thunderstorms will begin as only a
chance, but then increase to likely over most of the area during the
day Wednesday. The flow will become more zonal at this point and
this will allow another weather system to move toward the area for
the latter part of the week. This next system looks on the weak side
and will be moisture limited. So, for now will just have a slight
chance of precip, which will not get mentioned in the worded
forecast, but will show up in the grids.
Temps will become warm, above normal, for Sunday, ahead of the next
weather system. However, with the second high pressure area moving
into the region temps will drop back to more seasonable levels for
next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1248 PM CDT Fri Oct 21 2016
Low VFR ceilings persist at both KDEC and KCMI early this
afternoon...as low-level moisture continues to flow S/SW from
Lake Michigan. Based on latest visible satellite imagery showing
cloud cover becoming more widespread across east-central Illinois,
think the HRRR may be slightly too fast to clear things out later
today. As a result, have maintained 3500ft ceilings at KDEC
through 21z and KCMI through 23z. These diurnally driven clouds
will then dissipate by sunset. Skies will remain mostly clear at
the remaining terminals, although all models predict an area of
high/thin clouds will pass overhead tonight. Winds will initially
be from the NW at around 10kt this afternoon, then will back to
the SW by Saturday morning as high pressure drifts east of the
region.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Barnes
Area Forecast Discussion
National Weather Service Northern Indiana
256 PM EDT Fri Oct 21 2016
.SYNOPSIS...
Issued at 242 PM EDT Fri Oct 21 2016
Lake effect cloud and scattered rain showers will persist downwind
of Lake Michigan into this evening. A few lake effect rain showers
may also move off of Saginaw Bay and briefly approach portions of
south central Lower Michigan. Outside of any cloud cover,
temperatures will fall into the 30s for overnight lows with some
patchy frost possible. Locations that remain in the clouds will
see lows in the upper 30s to around 40. Clouds will slowly break
up during the day Saturday with highs in the 50s.
&&
.SHORT TERM...(This Evening through Saturday)
Issued at 240 PM EDT Fri Oct 21 2016
Deformation zone from low pressure moving into the NE states has
finally shifted well east of the area. North to northwest flow
over Lake Michigan has allowed lake effect clouds and scattered
rain showers to develop and now shift into SW Lower Michigan and
NW Indiana. HRRR has a decent handle on uptick in coverage and
intensity of diurnally driven pockets of brief moderate rainfall.
A few showers were even making a run at NE sections courtesy NE
flow off Lk Huron/Saginaw Bay. Lake Michigan activity will persist
into the late evening and even overnight hours but should lose
some of its coverage and intensity as inversion heights begin to
lower and diurnal impacts are felt. going no more than mid to high
chc pops to cover the main band.
On Saturday deeper moisture will begin to wane with inversion
heights continuing to lower, resulting in decreasing clouds and
lake effect impacts. Highs will be on the cooler side with
temperatures ranging from the lower 50s NE near the core of the
coldest air to the upper 50s in the SW.
&&
.LONG TERM...(Saturday Night through Friday)
Issued at 240 PM EDT Fri Oct 21 2016
Generally quiet period through mid week for the area with only
sensible weather issue being weak disturbance dropping through the
northern lakes that may bring a increase in cloud cover north of
US 6. Otherwise, main system will be mid to lake week as trough
rapidly develops across the western Great Lakes and deepens with
shower (thunderstorm?) chances increasing Weds afternoon into
Weds night. Generally went with Superblend of pops through the
period with lingering precip even into Thursday and Thursday
night as trough become negatively tilted. Temperatures will warm
towards more seasonable readings late in the period.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 101 PM EDT Fri Oct 21 2016
Cool northerly flow expected this afternoon into this evening in
wake of low pressure system. This cold advection over relatively
warm lake waters will keep lake effect stratocu around through
much of the period...especially this afternoon/evening at KSBN
when lake effect rain showers will be possible. Under the lake
effect bands CIGS will down between 2 kft and 3 kft. VFR outside
of the lake effect showers.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 5 AM EDT Saturday for LMZ043-046.
&&
$$
SYNOPSIS...Heidelberger
SHORT TERM...Fisher
LONG TERM...Fisher
AVIATION...Heidelberger
Visit us at www.weather.gov/iwx
Follow us on Facebook...Twitter...and YouTube at:
www.facebook.com/NWSNorthernIndiana
www.twitter.com/nwsiwx
www.youtube.com/NWSNorthernIndiana